identifier: Whitten, Rhonda Joyce <https://research.library.mun.ca/view/creator_az/Whitten=3ARhonda_Joyce=3A=3A.html>   (1995) Alcohol modulation of GABAA receptors : subunit requirements and structure-activity relationships.  Masters thesis, Memorial University of Newfoundland.

abstract: Alcohols are believed to exert their behavioural effects at least in part by a selective enhancement of γ-aminobutyric acid type A (GABAA) receptor activity. However, the mechanism(s) by which ethanol and other alcohols facilitate GABAA receptor function have remained elusive. Historically,  alcohols have been thought to act by partitioning into membrane lipids to cause changes in the function of membrane  proteins. However, more recent evidence suggests that alcohols interact selectively with hydrophobic regions of specific membrane proteins or phospholipids to alter their function. If a drug-protein interaction is involved in the effects of alcohols on GABAA receptor function, it was hypothesized that stereoisomers of a simple straight-chain alcohol might show differential effects on receptor function. Alternatively, there may be differences in the effects of closely related alcohols that are not predicted by differences in lipid solubility, and/or a significant influence of the subunit composition of the GABAA receptor itself. To test these hypotheses concerning the mechanisms of action of alcohols, cloned subunits of human GABAA receptors were expressed in Xenopus laevis oocytes, and the two-electrode voltage-clamp technique was used to quantify the membrane current response to GABA in the presence and absence of different alcohols. -- 1-butanol and 2-butanol differentially potentiated GABA responses in both α₁β₂γ₂L and  α₂β₂γ₂L receptor constructs, with 2-butanol being significantly more potent than 1-butanol as a modulator of GABAA receptor function. However, 2-butanol has a lower membrane/buffer partition coefficient, and is therefore less  lipid soluble than 1-butanol. Thus, the structure of the alcohol, rather than simple lipid solubility, was more important as a predictor of modulation of GABAA receptor function. In contrast, the stereoisomers (R)-2-butanol and (S)-2-butanol did not differ in their modulation of receptor  function. 1-butanol and 2-butanol were also significantly more potent as modulators at α₂β₂γ₂L compared to α₁β₂γ₂L GABAA  receptor constructs. Thus, the subunit composition of the receptor protein also influences modulation of receptor function by alcohols. The γ₂L subunit, which is reported to be necessary for ethanol to potentiate GABAA receptor activity, was not required for 1-butanol or 2-butanol to increase GABA-mediated responses. Low concentrations (20 mM)  of ethanol potentiated GABAA receptor function at α₁β₂γ₂L receptors. Ethanol potentiation of GABAA receptor function was blocked by 0.5 μM Ro15-4513, a benzodiazepine receptor partial inverse agonist. However, Ro15-4513 at concentrations up to 5 μM did not block potentiation of GABAA receptor activity by butanol, heptanol, or the non-volatile anesthetic propofol. -- Differential effects of alcohols on GABAA receptor function in response to changes in subunit composition or structure of the alcohol suggest specific interactions of these agents with the receptor complex. In addition, it appears that longer-chain (≥ 4 carbons) alcohols act at a different site and/or induce a different conformational change in the receptor compared to ethanol. In conclusion, these data support the idea that alcohols have specific interactions with the GABAA receptor,  rather than simply disordering membrane lipids. In addition,  there may be at least two distinct mechanisms and/or sites by which alcohols can act to modulate activity at the GABAA receptor.


identifier: Skanes, Verna M. Robbins <https://research.library.mun.ca/view/creator_az/Skanes=3AVerna_M=2E_Robbins=3A=3A.html>   (1983) Allotypes of the fourth component of complement in healthy and disease families.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

type: Thesis NonPeerReviewed

format: application/pdf application/pdf

abstract: 1857 serum samples from healthy individuals, patients, and their families were characterized with respect to C4 polymorphic variants, the relationship between genotype and C4 concentration, associations between C4 haplotypes and other MHC variants, and the inheritance of C4 and other MHC allotypes in multiple sclerosis (MS) and insulin-dependent diabetes (IDDM) families. -- Patterns obtained were consistent with (i) two gene products, C4A (Rg+) and C4B (Ch+), (ii) two loci, A and B, per chromosome, (iii) at least five alleles at each locus, A3 and B1 being the most common, and (iv) moderately frequent null alleles, AQO and BQO. Some individuals with the rare patterns A3A2 and B2B1 appeared to have two A or two B genes per chromosome. For two rare products, B3 and B4, the appropriate Chido antigen could not always be demonstrated. -- Null alleles could not  be excluded from many A3B1 phenotypes. Measurement of relative amounts of C4A and C4B products per individual and of total serum C4 is of limited value in predicting the number of genes an individual possesses. Factors other than MHC-linked genes are likely to be important in determining serum C4 levels. -- Frequencies of C4 haplotypes and of C4*A  and C4*B genes were estimated from 1048 founder haplotypes. Five A-B combinations had frequencies > 2% and were non-randomly associated. -- Many MHC alleles, C4-C2-BF complotypes, and extended MHC supratypes showed high positive linkage disequilibria. The associations suggest that the C4 loci are between HLA-B and HLA-DR, closer to HLA-DR. The frequent clustering of rare C4, BF, and C2 alleles in the same supratype indicates that some may be hypermutable. -- Supratypes of patients were compared with non—disease supratypes from the same families. HLA-B7 C4*A3B1 BF*S C2*1 HLA-DR2 was increased in MS-patient supratypes. This is likely to reflect strong associations among these alleles and between MS and HLA-DR2 suggesting that an MS susceptibility gene is very closely linked to HLA-DR. C4*AQ0B1 and C4*B3 occurred more frequently in IDDM supratypes. These associations may also be secondary to strong associations reported for IDDM and HLA-DR or, because  other rare complement variants are associated with IDDM, may  indicate a direct role for particular complement variants in  this disease.


identifier: Doshi, Sharat <https://research.library.mun.ca/view/creator_az/Doshi=3ASharat=3A=3A.html>   (1990) An epidemiological study of dental disease and dental health behaviour of school children 6-7 and 13-14 years of age in rural Newfoundland, Canada.  Masters thesis, Memorial University of Newfoundland.

abstract: KEYWORDS: epidemiology; oral; behaviour; prevalence; dental caries; DMF index; rural Canada; ethnicity; socioeconomic factors; utilization of services; periodontal disease -- A cross-sectional epidemiological study was carried out in 1985 to investigate the prevalence of and risk factors associated with dental disease in school children aged 6 - 7  and 13 - 14 years living in Coastal Labrador and remote parts of the Island of Newfoundland. -- The participants were selected by means of a stratified two-stage probability  cluster sampling design. Strata consisted of seven geographic areas. Schools within each area were the primary sampling units. Within the schools selected for the study, a  sample of school children within each of the relevant grades  was selected. -- Information about the relevant clinical, sociodemographic and behavioural data was gathered through an oral examination of the children and a questionnaire administered either to the children or their parents. Data concerning the dependent variable, oral health status, included measurement of decayed, missing and filled tooth surfaces (DMFS), orthodontic status and prevalence and severity of periodontal disease (Russell's PI). -- Response to request for participation in the study was 285 (82.9%) in  the 6 - 7 year olds and 294 (86.7%) in the 13 - 14 year olds. The number and (%) of the consented that were examined, recorded and subsequently analysed was 244 (85.6%) in the younger age group and 229 (77.9%) in the older students. -- The analyses of data from 473, 6 - 7 and 13 - 14 year old school children residing in remote districts of the Province of Newfoundland, Canada, resulted in the following conclusions: -- 1. In both 6 - 7 and 13 - 14 year age groups, increased parental education level was associated with a significant decrease in DMFS index, largely due to decrease in decayed and missing surfaces. In addition, in 13 -14 year olds, increased parental education level also indicated a significant increase in level of treatment. -- 2. Compared with students having little or no exposure to fluoridated water, the 13 - 14 year old students  with histories of one or more years of residence in fluoridated communities had significantly less caries experience and significantly lower levels of treatment manifested by restorations; the 6 - 7 year olds with similar  histories of residence in fluoridated communities had significantly less filled surfaces. -- 3. Compared with similar aged school children living in other areas of the province, remote children had a greater average number of teeth decayed and missing due to caries, and a lower average  number of teeth filled; remote children had a greater need for treatment as measured by the mean number of teeth per student needing various types of treatment; and remote children had a greater proportion of students requiring various dental services. -- 4. Russell's periodontal index (PI) was higher in remote children in both 6 - 7 and 13 - 14  year age groups than similar aged children residing in less remote parts of the province. -- 5. Compared with 6 - 7 and 13 - 14 year old Native Indian children, settler (predominantly Caucasian) children in remote areas in both age groups had significantly greater caries experience and significantly more missing surfaces. -- 6. No significant difference in caries experience was found between Inuit and settler (predominantly Caucasian) children in remote areas in the 13 - 14 year old age group. -- In remote areas of the  Province of Newfoundland, the risk of developing dental caries (tooth decay), the most prevalent of the chronic oral  diseases, appears to be low for those children having a history of exposure to fluoridated water and for those children indicating a high parental education level. The data from this study support the notion that water fluoridation is the principal choice among the alternatives available for the prevention and control of this main dental  disease. In future studies, the effectiveness and efficacy of diet, education, tooth-brushing, water fluoridation and other preventive programs in reducing the incidence and prevalence of dental caries, and in erasing the differences in dental caries rates between the different social classes,  should be examined.


identifier: Roberts, Patricia Margaret <https://research.library.mun.ca/view/creator_az/Roberts=3APatricia_Margaret=3A=3A.html>   (1983) An evaluation of the usefulness of Rodbard's sphygmomanometric method in cardiovascular epidemiology.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: The purpose of this study was to test the hypothesis that Rodbard's method of noninvasively determining the anacrotic slope of the brachial artery pressure pulse wave is useful in cardiovascular epidemiology. -- The materials were the raw records obtained for two groups of subjects aged 55 years living an Göteborg in 1969/70, and the cardiovascular disease information registered for these subjects in the following ten years. The method of checking on the hypothesis was to determine if there was a significant relationship between any of the eleven variables used to quantify the anacrotic slope obtained for each subject and his cardiovascular history in the follow-up period. Because an understanding of the physiological mechanisms was essential for the correct interpretation of any significant results, these mechanisms were evaluated by first submitting  the variables to factor analysis and covariance analysis. -- The means and the factor score coefficients of the variables were not found to be related to the development of cardiovascular disease in the follow-up period. However, a significant relationship was found between one pair of vari-ables in combination (systolic pressure and the gradient of the initial, linear portion of the anacrotic slope) and the subject's risk of experiencing a stroke in the follow-up period. -- It was concluded that Rodbard's method has the potential to be useful in cardiovascular epidemiology because one member of the pair of variables determined to be  of value (the gradient of the initial, linear portion of the  anacrotic slope) can be easily obtained only by Rodbard's method. -- Two important additional conclusions arose from the use of factor analysis and covariance analysis: it is possible to estimate peripheral resistance noninvasively where systolic pressure and the gradient of the initial, linear portion of the anacrotic slope are known, and it is not necessary to correct the variables for differences in heart rate.


identifier: Qian, Hong <https://research.library.mun.ca/view/creator_az/Qian=3AHong=3A=3A.html>   (1995) Investigation of signal transduction mechanisms regulating CD14 expression and shedding by monocyte derived macrophages.  Masters thesis, Memorial University of Newfoundland.

abstract: CD14 expression and shedding are important in the regulation  of cellular responses to lipopolysaccharide (LPS) and concomitant production of cytokines and related immunological and pathophysiological changes. The rapid shedding of CD14 from monocytes, subsequent to contact with LPS, has led us to hypothesize that signalling events through the CD14 receptor complex are involved in the activation of enzymes responsible for the cleavage and loss of CD14 from the cell surface. This then ultimately regulates cellular responses to lipopolysaccharide. This hypothesis was tested using a number of signal transduction modulating agents to inhibit or activate secretions of the CD14 signalling pathway. Besides LPS, two other natural ligands tumour necrosis factor α (TNF-α) and formyl-methionyl-leucyl-phenylalanine (f MLP) were investigated to observe if they also had a role in regulating CD14 expression or loss. TNF-α, a cytokine released rapidly following LPS contact with CD14 on monocytes, was suspected of having a negative feedback control on monocytes by blocking LPS signalling or increasing CD14 loss from the monocyte surface. The other ligand, f MLP, was known to have  chemotactic activity for both monocytes and neutrophils. Although f MLP has its own receptor, it activates monocytes in a number of ways that are similar but not identical to LPS and may share common signalling pathways. In these studies only early events, up to 4 hours, were investigated using FACS analysis to follow CD14 expression, and immunoprecipitation and 2D-SDS PAGE analysis of membrane and  soluble CD14 to confirm the mechanism and characterize the products released from cells. It was found that the most active pharmacological agents, inducing loss of membrane CD14 from monocytes, were regulators of PKC or cytoplasmic calcium levels. It was also found that fMLP was able to induce a rapid loss of membrane CD14 expression from monocytes. TNF-α, on the other hand, had reverse effect and caused a rapid increase in CD14 expression by monocytes. -- As a result of the initial investigations into the action of  various signalling pathway inhibitors on CD14 expression and  shedding, an interesting observation was made with calphostin C, a photoactivated protein kinase C inhibitor. This compound was found to induce 100% loss of CD14 expression from normal human peripheral blood mononuclear cells and the human monocytic leukaemia cell line, THP-1, through membrane vesicle shedding or apoptosis. Further investigation found that Ca²⁺ dependent K⁺ channels were also involved in the regulation of apoptosis induced by calphostin C. These data were presented at the Paris Conference on Apoptosis in AIDS and CANCER (Qian,H., Liepins,A., Richardson,V.J., p113. Dec.2-4, 1993, Paris, France. Abstract attached to the following page). -- Finally, ouabain, an inhibitor of Na⁺/K⁺-ATPase, was also found to induce a rapid and complete loss of membrane CD14. Using 2D-SDS-PAGE analysis, this did not appear to be due to  apoptosis or shedding of CD14 into the media.


identifier: Crooks, R. Peter <https://research.library.mun.ca/view/creator_az/Crooks=3AR=2E_Peter=3A=3A.html>   (1996) Ischemic preconditioning provides histological but not behavioral protection in the gerbil.  Masters thesis, Memorial University of Newfoundland.

abstract: It has been demonstrated that brief duration (e.g. 1.5-2 min) ischemia can provide neuroprotection against subsequent insults of longer duration.  This phenomenon of ischemic tolerance or ischemic preconditioning was first reported in 1990 and has since received tremendous attention.  The purpose of this investigation was to determine what effect ischemic preconditioning has on post-ischemic brain temperature, to assess whether histological preservation translates into functional protection and to observe whether there is a decline in neuroprotection with a longer survival time in a gerbil model of global ischemia. -- This study clearly demonstrated that preconditioning episodes of short duration ischemia provided significant histological protection of CA1 pyramidal cells against a subsequent ischemic insult that would typically produce roughly 95% necrosis of these neurons.  Interestingly, histological protection in preconditioned ischemic animals did not result in concurrent behavioral protection.  Preconditioned ischemic animals displayed a consistent habituation deficit when placed in the open field and were not different from untreated ischemic gerbils.  A significant decline in CA1 preservation in preconditioned animals was observed when survival time was extended from 10 (81% protection) to 30 (53% protection) days.  The lack of functional protection within the first 10 days postischemia, concomitant with the decline of cellular preservation over time suggests that this paradigm may not provide permanent protection if assessed at 2 or 3 months later. -- Consistent damage was observed in sector CA2 of the hippocampus in 21/22 preconditioned gerbils.  Tolerance to ischemia failed to be induced in these neurons.  In addition, several preconditioned animals displayed damage in the subiculum.  Preconditioning ischemia did not affect the degree of hyperthermia observed following the lethal occlusion but did significantly reduce the duration of hyperthermia.  However, this effect was small and thus ischemic preconditioning does not appear to be acting via a temperature mediated process. -- In light of the present findings, future research must be directed towards determining if the histological protection observed at 30 days is permanent or whether cell death would continue with longer survival times.  Electrophysiological recording from CA1 would also help determine if these preserved” CA1 neurons are fully functional.  In the future the mechanisms of ischemic tolerance may be able to be activated pharmacologically thereby providing a novel therapy for the treatment of stroke.


identifier: Jahagirdar, Ravindra V. <https://research.library.mun.ca/view/creator_az/Jahagirdar=3ARavindra_V=2E=3A=3A.html>   (1994) Isolation and characterization of an operon, exeAB, containing two genes which are required for extracellular protein secretion in Aeromonas hydrophila.  Masters thesis, Memorial University of Newfoundland.

abstract: Aeromonas hydrophila secretes many proteins into the extracellular milieu.  Strain C5.84 is a Tn5-751 insertion mutant of this bacterium which is unable to secrete extracellular proteins, instead accumulating them in the periplasm (Jiang and Howard, 1991).  A 3.5 kb Bgl II fragment which complements the mutation in C5.84 was isolated from the chromosome of the wild type strain and sequenced.  Computer analysis of this fragment revealed an operon-like structure with two complete genes, exeA and exeB, a promoter 5' to the exeA gene and a 13 base pair inverted repeat immediately 3' to the exeB gene.  Although the transposon had inserted in exeA, provision of a wild type copy of this gene alone in trans did not restore competence for export to C5.84.  Complementation required the presence of both exeA and exeB, and marker exchange mutagenesis further established the requirement for both gene products for extracellular secretion.  In addition, immunoblots with an anti-ExeB serum demonstrated that the Tn5-751 insertion in exeA had a polar effect on the expression of exeB. -- In vivo and in vitro expression studies confirmed that there is a promoter 5' to exeA and that exeA and exeB form an operon.  Analysis of the deduced amino acid sequence of ExeA indicated that it is a hydrophilic 60 kDa protein with a consensus ATP-binding site.  ExeB is a 25 kDa basic protein which shares limited homology with PulB, a protein of unknown function associated with the maltose regulon of Klebsiella oxytoca, and OutB, a protein which has been shown to be required for efficient secretion in Erwinia chrysanthemi.  The hydropathy analysis of these proteins and preliminary localization studies suggested that both ExeA and ExeB may be anchored to the inner membrane. -- These results demonstrate the requirement of a second operon encoding a putative ATP-binding protein in the secretion of extracellular proteins from Gram-negative bacteria, and further suggest that the cytoplasmic compartment may play a greater role in protein translocation across the outer membrane from the periplasm than previously thought.


identifier: Maitra, Rajatavo <https://research.library.mun.ca/view/creator_az/Maitra=3ARajatavo=3A=3A.html>   (1995) Interaction between propofol and benzodiazepine site ligands to potentiate GABAA receptor activation in human recombinant receptors expressed in Xenopus oocytes.  Masters thesis, Memorial University of Newfoundland.

abstract: Potentiation of inhibitory synaptic transmission mediated by  γ-aminobutyric acid (GABA) acting at the GABA type A (GABAA)  receptor is increasingly regarded as a primary site of action for anesthetic drugs. GABAA receptors across different brain regions can have a different protein subunit  composition, which influences the pharmacological sensitivity of the receptor complex. The intravenous general  anesthetic propofol is frequently combined with benzodiazepines, and there are reports of synergism in the production of anesthesia. However, the nature of this interaction is unknown. The purpose of this study was therefore to examine the interaction between propofol and the benzodiazepine receptor agonist flurazepam at the receptor level. In addition, preliminary studies on the influence of subunit composition on the potentiation of GABAA receptor function by propofol have been carried out. Two-electrode voltage-clamp recording of GABA-activated membrane currents were performed in Xenopus laevis oocytes expressing human recombinant GABAA receptors. -- Propofol was found to produce similar potentiation of GABA (3 μM) receptor-activated currents in receptors composed of α₁β₂γ₂L and α₂β₂γ₂L subunits. Propofol appears to increase the affinity of GABAA receptors for GABA without changing the maximal current. In contrast, propofol potentiation of GABA currents was influenced by the γ₂L subunit. Receptors composed of α₂β₂ subunits were potentiated to a greater extent than receptors composed of α₂β₂γ₂L subunits. The time course of GABAA receptor desensitization can be described by  a double exponential function. Propofol was found to reduce receptor desensitization by significantly prolonging the slow time constant of current decay, resulting in a large increase in the steady-state current activated by a high GABA concentration. -- The interaction between propofol and flurazepam was examined in receptors composed of α₂β₂γ₂L (x =  1 or 2) subunits. Currents activated by GABA (3-30 μM) were potentiated by low concentrations of propofol (0.5-10 μM) plus flurazepam (0.25 and 0.5 μM) to levels which were significantly greater than expected from an additive response. At higher concentrations of propofol (20 μM) or flurazepam (1 μM) the potentiation of GABA receptor-activated currents was not different than expected from an additive response. The benzodiazepine receptor partial inverse agonist RO15-4513 was found to abolish the flurazepam potentiation of GABA-activated membrane currents without affecting the propofol response. Zopiclone, a cyclopyrrolone derivative which is classified as a full agonist at benzodiazepine receptors, did not produce the same greater than additive interaction with propofol. In fact, zopiclone (100 nM) combined with propofol (1-10 μM) produced an enhancement of the GABA current which was significantly less than the expected additive response. -- These results suggest that propofol has multiple effects on GABAA receptor function: An increase in the affinity of the receptor for GABA plus a decrease in receptor desensitization at higher GABA concentrations. The type of α   subunit contained in the receptor does not appear to have a major influence on the ability of propofol to modulate GABAA  receptor function. However, propofol was significantly less effective in the presence of a γ₂L subunit. Thus similarly to many other modulators, potentiation of GABAA receptor function by propofol does exhibit subunit dependence. Synergism observed clinically by the combination of propofol  or propofol plus benzodiazepines can be explained by an interaction at the receptor level. In addition to increasing  the affinity for GABA, flurazepam increased the affinity of the receptor for propofol, resulting in a greater than expected potentiation of GABAA receptor function. This interaction between propofol and benzodiazepines was not due  to simple potentiation of GABAA receptor activity, since zopiclone failed to produce the supra-additive effect when combined with propofol.


identifier: Soneira Ruiz, Carlos Francisco <https://research.library.mun.ca/view/creator_az/Soneira_Ruiz=3ACarlos_Francisco=3A=3A.html>   (1994) Senile plaque formation and severe cardiovascular disease.  Masters thesis, Memorial University of Newfoundland.

abstract: Senile plaques are considered by many to be the most consistent neuropathologic feature of Alzheimer's disease, but they are also present in the brains of non-demented, elderly subjects.  Recent reports (Sparks et al, 1990, 1993) suggest that non-demented patients with critical coronary artery disease show a higher prevalence of senile plaques than non-demented subjects without heart disease.  The present study analyzes 40 autopsy brains which were divided into three groups according to the clinico-pathological findings:  an Alzheimer's disease group (n=12), a severe cardiovascular disease group (n=17) and a control group (n=11).  The brain areas examined were the middle frontal gyrus, the superior and inferior watershed areas, the hippocampal formation with the transentorhinal cortex, the primary visual cortex, the head of the caudate nucleus and the anterior lobe of the cerebellum.  Consecutive sections were stained with cresyl violet, the modified Bielschowsky method and immunohistochemistry for amyloid beta-protein.  Senile plaques and neurofibrillary tangles were counted in three and six microscopic fields at X100 and X200 magnification, respectively, and the mean values of the counts were calculated and used for statistical analysis.  Patients with severe cardiovascular disease (critical coronary artery disease and/or hypertension) showed a higher prevalence of senile plaques than the non-demented controls.  In the cardiovascular disease group senile plaque counts were significantly larger in the inferior watershed area, dentate gyrus, subiculum and transentorhinal cortex.  Control and cardiovascular disease patients showed no difference regarding the prevalence and number of neurofibrillary tangles.  In the sample examined, cardiovascular disease patients occupied an intermediate position in the spectrum of senile plaque formation between Alzheimer's disease and non-heart disease patients.  These results suggest that there might be a cardiovascular component in the genesis of senile plaques and that study of patients with severe cardiovascular disease may help to clarify the origin and evolution of these lesions.


identifier: Miller, Margaret <https://research.library.mun.ca/view/creator_az/Miller=3AMargaret=3A=3A.html>   (1989) The effect of chemical denervation on the action of acetylcholine and substance P in the isolated perfused mesenteric arterial bed of the rat.  Masters thesis, Memorial University of Newfoundland.

abstract: Vascular endothelial cells respond to certain vasoactive agents by releasing factors which act on medial smooth muscle to cause relaxation or contraction of blood vessels.  One of the substances responsible for endothelium-dependent relaxation to acetylcholine has recently been identified as nitric oxide.  We have tested the hypothesis that the ability of vascular endothelium to cause relaxation in response to stimulation by vasoactive agents is related in some way to the pattern of perivascular innervation.  The actions of acetylcholine and substance P were tested in the presence of methoxamine induced tone in the isolated perfused mesenteric arterial bed of the rat.  Tissues were tested from untreated normal 12 week old Sprague-Dawley rats and from rats which had been treated from birth with capsaicin to prevent the development of peptidergic perivascular innervation or 6-hydroxydopamine to prevent development of catecholaminergic innervation.  Concentration dependent endothelium-dependent relaxations were observed in response to acetylcholine.  The concentration response curve to acetylcholine was shifted 1.2 log units to the right in the capsaicin-treated group but no change was observed with 6-hydroxydopamine treatment.  Substance P caused a dose dependent potentiation of the methoxamine induced tone which was not dependent on the presence of an intact endothelium.  Relaxations to substance P were not observed at any dose.  Sympathectomy with neonatal 6-OHDA treatment resulted in an increase in the substance P pressor response, but no changes were observed with capsaicin treatment.  Thus, it appears that altering the peptidergic perivascular innervations results in a decreased sensitivity of the mesenteric arterial bed to acetylcholine and changes in the catecholaminergic fibre plexus result in an enhancement of the substance P modulation of adrenergic vasoconstriction.


identifier: King, Shelley R. <https://research.library.mun.ca/view/creator_az/King=3AShelley_R=2E=3A=3A.html>   (1994) The effect of peripheral deafferentation on specific axonal systems and glial elements in the main olfactory bulb of the rat.  Masters thesis, Memorial University of Newfoundland.

abstract: Heterotypic collateral sprouting of neurotransmitter systems  has been observed in many regions of the CNS following injury. The olfactory bulb (OB) receives direct input from the olfactory epithelium and its neuroanatomy and neurotransmitter content have been well characterized. Thus,  the OB may provide a useful cortical model of lesion-induced  plasticity. The present study has tested the hypothesis that  heterotypic collateral sprouting of specific axonal systems,  especially the serotonergic axons from the raphe, will occur  following peripheral deafferentation of the OB. In addition,  we hypothesized that an increase in the number of astrocytes  would occur following deafferentation of the OB. In this study, serotonin, dopamine beta-hydroxylase, glial fibrillary acidic protein (GFAP) and S-100 (serotonergic growth factor) immunocytochemistry was performed to elucidate the response of different axonal systems and glial  elements to peripheral deafferentation of the OB. -- Deafferentation of the right OB was achieved by application of ZnSO₄ to the olfactory epithelium (OE) of adult male rats  and postnatal day (PND) 10 rat pups. The effectiveness of the lesion was determined by the degree of the loss of tyrosine hydroxylase (TH) immunoreactivity in the periglomerular cells which require the presence of the OE to  express the TH phenotype. The deafferentation resulted in a decrease in the density of serotonergic fibres in the deeper  regions of the lesioned OB in adult animals which is in contrast to the increase in density evident in the PND 31 animals. The density of astrocytes expressing S-100, a proposed serotonergic growth factor, did not correlate with the density of serotonergic innervation. In contrast to the serotonergic system, the density of noradrenergic fibres in the lesioned OB was increased in the adult animals, but remained unchanged in PND 31 rat pups. The densities of GFAP  positive astrocytes in the lesioned OB of adult and PND 31 animals were similar to those of control animals. These results suggest that deafferentation of the OB of adult animals did not induce heterotypic sprouting of intact serotonergic fibres in the three week time period. On the contrary, the serotonergic fibres were selectively decreased, perhaps due to the potential neurotoxicity of zinc to these fibres. It appears, however, that the serotonergic fibres in the younger animals are capable of sprouting in response to OB deafferentation and this response may be related to the indirect neuromodulatory effects of zinc.


identifier: Gosse, Verena Florence <https://research.library.mun.ca/view/creator_az/Gosse=3AVerena_Florence=3A=3A.html>   (1988) Hardiness, sense of coherence, and potency : their relationship to each other, and to health practices.  Masters thesis, Memorial University of Newfoundland.

abstract: In recent years, considerable attention has been paid to personality dimensions as modifiers of the stress-illness relationship.  Included amongst those modifiers investigated have been hardiness, sense of coherence, and potency.  The purpose of this study was to investigate the apparent similarity among these three constructs, and among their components.  As well, the relationship between the three personality constructs and the occurrence of health protective behaviours was examined. -- Questionnaires measuring the personality constructs and health behaviours were administered to 314 subjects.  The results indicated that there was a positive and substantial relationship among the three personality constructs, and among their components.  The hypothesized relationship between the personality constructs and health protective behaviours was also supported.


identifier: Butler, John Spencer <https://research.library.mun.ca/view/creator_az/Butler=3AJohn_Spencer=3A=3A.html>   (1995) Health care resource utilization in Newfoundland.  Masters thesis, Memorial University of Newfoundland.

abstract: Health care delivery is not subject to the economic forces which achieve productive and allocative efficiencies in competitive markets. Allocative efficiency is addressed in the context of a methods review for measuring hospital bed utilization. Productive efficiency is addressed by examining  the utilization of ciprofloxacin, an expensive antibiotic. -- The reliability and validity of several methods of measuring hospital bed utilization were assessed. Nurse (A) prospectively collected data on the clinical condition and care plans of 80 patients at an acute care hospital, and identified and classified inappropriate days using her clinical judgement. In the same way, a second nurse (B), experienced in appropriateness evaluation, independently rated the same cases as did a third nurse (C), using a modified version of the Appropriateness Evaluation Protocol (AEP). Nurse A's data was also independently rated by a panel (P). Agreement for the number of inappropriate hospital days per case as measured using the Intraclass Correlation Coefficient (Rx) was excellent: Nurse A v P = 0.95, Nurse A v C = 0.87, P vs C = 0.88, B v A = 0.87, B v P  = 0.79, B v C = 0.72. Reliable and valid judgements of inappropriateness can thus be made by any of these methods. -- In the second study, an academic panel and an industry panel used guidelines to assess the appropriateness of 278 ciprofloxacin prescriptions which were generated through chart review and interview of 72 physicians. Ciprofloxacin was considered to be appropriately prescribed in 42% of cases by the academic panel, and in 62% by the industry panel. The only diagnoses where the two panels differed significantly were nursing home-acquired pneumonia (p < 0.0005) and acute exacerbation of chronic bronchitis (AECB) (p < 0.0001). Agreement between the two panels was fair (K =  0.36), but agreement increased to moderate when cases of nursing home-acquired pneumonia and AECB were removed (K = 0.58). -- Inappropriate prescription of ciprofloxacin inhibits productive efficiency in the health care system and  stems from a combination of lack of knowledge of pharmacotherapy for common infections, as well as a lack of knowledge or concern for the cost differential among antibiotic alternatives. Physician education through academic detailing is needed to disseminate price information and appropriate guidelines with the intent of improving physician prescribing behaviour.


identifier: James, Bonita Maria <https://research.library.mun.ca/view/creator_az/James=3ABonita_Maria=3A=3A.html>   (1990) Needlestick injuries in nursing and laboratory personnel.  Masters thesis, Memorial University of Newfoundland.

abstract: This study was designed to increase understanding of needlestick injuries in order to make recommendations for appropriate preventive measures. -- Needlestick injury rates  for the period 1985-1989 were calculated for nursing and laboratory employees at three tertiary care hospitals, using  staff health records and an anonymous self-administered questionnaire. -- In 1989, hospital-recorded needlestick rates ranged from 12 to 24 per 100 FTE (full-time equivalents) for nurses and 4 to 23 per 100 for laboratory employees in the study hospitals. No decline in rates of reported needlesticks for all hospital employees or for nurses was seen; a decline in needlestick frequency was seen  in two of the three laboratories. -- A random sample of nurses who ordinarily use needles in their work and all laboratory employees who regularly collect blood were invited to participate in a survey describing needle use patterns and needle injury experiences. Responses were received from 86% of nurses and 83% of laboratory employees contacted, for a total of 342 survey participants. -- Rates of self-reported needlesticks for the previous twelve months  were 74 per 100 nurses and 24 per 100 laboratory employees. Forty-one percent of nurses and 20% of laboratory employees had one or more injuries in the last year. The risk of needlestick injury was not associated with an employee's sex, education level, job status, knowledge and beliefs about needlesticks, or personal health practices. Factors associated with having been injured included: -- 1) need to carry used needles to a disposal container, -- 2) recapping used needles using two hands, -- 3) inconsistent discarding of uncapped needles, -- 4) work area, -- 5) working experience, -- and 6) number of needles used. -- Most needlestick injuries occurred after the needle had been used; 42% involved recapping the used needle. Most of the recent needlesticks experienced by nurses involved disposable syringes or automatic spring-loaded lancets. Almost all needlesticks described by laboratory employees involved vacuum-tube blood collection equipment. -- Programs  to reduce needlestick injuries should include: -- 1) point-of-use placement of disposal containers; -- 2) attention to equipment and situations requiring special handling, e.g., devices needing disassembly; -- 3) education strategies targeted at groups at higher risk, such as newly employed nurses; -- 4) evaluation of the efficacy of needlestick prevention programs.


identifier: Wright, Jonathan Mark Campion <https://research.library.mun.ca/view/creator_az/Wright=3AJonathan_Mark_Campion=3A=3A.html>   (1984) Negative transcriptional control of the ornithine decarboxylase gene (SpeC) by cyclic AMP in Escherichia coli.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: The putrescine biosynthetic enzyme, ornithine decarboxylase (E.C. 4.1.1.17), is negatively regulated by cAMP in Escherichia coli.  The specific activity of ornithine decarboxylase was determined in crude extracts prepared from wild-type strains of E. coli and from strains carrying a mutation in the adenylate cyclase (E.C. 4.6.1.1) structural gene (cya).  These strains were grown with various carbon sources in the presence and absence of cAMP.  In wild-type strains ornithine decarboxylase activity was was less after growth on glycerol than after growth on glucose.  When cya strains were grown on glucose or glycerol, ornithine decarboxylase activity was the same.  Addition of 1 mM cAMP to a glucose-based medium repressed ornithine decarboxylase activity by approximately 50% in both wild-type and cya strains.  Furthermore, cAMP exerts its negative control through the cAMP receptor protein (CRP), because a strain carrying a lesion in the crp structural gene failed to exhibit repressed ornithine decarboxylase activity in response to elevated cAMP.  These results suggested that negative regulation of ornithine decarboxylase is exerted at the level of transcription.  Negative control was shown not to be mediated by a cAMP-induced repressor because synthesis of ornithine decarboxylase in E. coli minicells, and in a cell-free protein synthesizing system, was repressed by cAMP.  Repression of ornithine decarboxylase synthesis by cAMP in vitro required functional CRP as evidenced by the lack of repression in a CRP deficient reaction system.  The tetracycline resistance of E. coli wild-type and cya strains harbouring a tetracycline resistance gene (tet) under control of the speC promoter was repressed by cAMP.  Cyclic AMP had no effect, on the tetracycline resistance of crp strains bearing the speC:tet gene fusion, nor on wild-type strains bearing a normal tet gene.  These results indicate that cAMP and its receptor protein interact with the speC promoter region to facilitate negative transcriptional control of the speC gene.  Negative control of speC transcription by cAMP was confirmed by analysis of steady-state levels of ornithine decarboxylase mRNA in cya and crp strains of E. coli.  Ornithine decarboxylase mRNA levels were repressed approximately 80% when cya strains were grown in the presence of 2 mM cAMP.  No repression of ornithine decarboxylase mRNA levels was seen in a crp strain cultured in the presence of cAMP.


identifier: Daniel, Enoch S. <https://research.library.mun.ca/view/creator_az/Daniel=3AEnoch_S=2E=3A=3A.html>   (1995) Multiple factors shape the TCR Vβ repertoire in humans.  Masters thesis, Memorial University of Newfoundland.

abstract: Contributions to the human peripheral TCR Vβ repertoire were  assessed by a semi-quantitative PCR method. Lymphocytes were  expanded by PHA using a stimulation protocol that did not alter the Vβ repertoire. Marked differences in PCR-priming efficiencies of 23 Vβ segments were identified. Significant correlations between priming efficiencies and the observed Vβ repertoire were found and therefore the data were corrected for differences in priming efficiencies. Vigorous statistical analysis showed that non-genetic factors were responsible for significant differences between total T cell Vβ repertoires of monozygotic twin pairs and unrelated pairs. In preliminary analysis, however these influences were misinterpreted as having a genetic basis. No evidence was obtained that genetics (including HLA) influenced the total T cell Vβ repertoires. However, the role of genetics in influencing the Vβ repertoire of CD4⁺ or CD8⁺ T cell subsets could be detected at the level of a few Vβs. -- Large families were studied to delineate the effects of HLA on the TCR Vβ repertoire. The results of these studies indicated that HLA influenced the Vβ repertoire but that non-HLA factors also have a significant influence. -- Further, it was found that particular Vβs (15,16,18) were expressed at a constant level and several Vβs (particularly 10 and 12) were typically highly variable in expression levels. This was true for all individuals irrespective of the genetic background (including HLA) and irrespective of the T cell type. Still other Vβs tended to be highly variable in expression in CD4⁺ or CD8⁺ subsets but not in both. -- These studies unequivocally document that influences on the Vβ repertoires are complex. Genetics including HLA seem to play a role, however non-genetic influences can also have a major role in determining the TCR  Vβ repertoire.


identifier: Samuels, Lewis <https://research.library.mun.ca/view/creator_az/Samuels=3ALewis=3A=3A.html>   (1995) The effect of pre-existing antibody on the result of immunization of mice with human B cell lines and transfected mouse cell lines.  Masters thesis, Memorial University of Newfoundland.

abstract: Henry and Jerne (1968) described an interesting phenomenon, when SRBC's were used as antigen, the presence of IgG antibody prior to injection of antigen led to a suppressed response. In contrast, pre-existing IgM resulted in an increase of the primary immune response. The aims of this project were twofold, to determine if the same phenomenon is  observed when using either human B cells or mouse transfected fibroblasts, as antigens; to study the feasibility of using IgM enhancement to improve the yield of  antigen-specific hybridomas from mice against HLA-DP and DR.  -- Studies were conducted using mice immunised either with a  mouse transfectant cell line expressing HLA-DP (L25.4) or a human B cell line (RAJI). Preliminary experiments uncovered an unexpected reverse dose response when L25.4 cells were used as immunogen. Pre-treatment of mice with antibodies to monomorphic HLA-DP determinants increased and suppressed the  responses as predicted; were statistically significant with both Raji and L25.4. In a second experiment, doubling of the  IgM dose led to an unexpected diminution of the primary response against L25.4 and revealed that the half life of the administered IgM antibody appeared to be lengthened. -- Experiments were then conducted to determine the value of IgM pretreatment in the creation of hybridomas specific for HLA-DP and HLA-DR epitopes. Mice were pretreated with varying amounts of IgM antibody and then immunized. Three days later their spleens were removed, cells counted and fusions performed. Spleen size was found to be increased in a stepwise fashion with increasing doses of IgM past a previously described antigen induced plateau. The low dose of IgM produced spleens predominately composed of B cells, increasing the IgM dose decreased the B cells but increased the T cells. The IgM pretreated animals gave a 22.8% yield of specific hybridomas whereas the control group produced an  8%yield of specific hybridomas. Within the IgM pretreatment group, 96%of the selected hybrids originated from the low dosage group, indicating that there may exist an optimum pretreatment dose for IgM. These preliminary experiments support the potential of specific antibody pretreatment in the modulation of the primary response and the development of antigen-specific hybridomas.


identifier: Hancock, Scott Stephen <https://research.library.mun.ca/view/creator_az/Hancock=3AScott_Stephen=3A=3A.html>   (1995) The effects of nerve-contact, membrane excitability, and synaptic activity on the regulation of sodium and potassium voltage gated ion channels in embryonic Xenopus muscle cells after one day in culture.  Masters thesis, Memorial University of Newfoundland.

abstract: The kinetics, density and distribution of ion channels on myocytes are altered significantly during development, by genetic cues and extrinsic factors such as excitability, synaptic activity, and nerve-contact. The effects of such extrinsic factors on the developmental expression of ion channels in embryonic Xenopus myocytes is the focus of this work. Whole cell currents were recorded from embryonic Xenopus muscle cells after one day in culture using a List patch clamp and standard recording conditions. (Moody-Corbett and Gilbert, Dev. Br. Res., 1990, 55: 139-142). Na⁺ currents (INa) and three types of K⁺ currents inward rectifier (IR), inactivating (IIK), and non-inactivating (IK) outward rectifiers were recorded from both nerve-contacted and non-innervated muscle cells. The influence of membrane excitability and synaptic activity were examined by  adding tetrodotoxin (TTX) and/or α-bungarotoxin (α-BTX) to the culture medium at the time of plating. Nerve-contact significantly increased the proportion of cells which displayed an INa and this increased expression was blocked when membrane excitability or synaptic activity was blocked.  These results suggest that INa was maintained by a positive feedback mechanism while the upregulation of INa following nerve-contact was dependent on synaptic function. Nerve-contacted muscle cells had a significantly increased probability of expressing IIK than non-contacted muscle cells and this increase was not blocked when membrane excitability or synaptic activity was blocked. These results  suggest that IIK was maintained by a separate mechanism than  INa. It was concluded that nerve-contact, membrane excitability, and synaptic activity all play distinct and different roles in altering Na⁺ and K⁺ current expression.


identifier: Liu, Mingfeng <https://research.library.mun.ca/view/creator_az/Liu=3AMingfeng=3A=3A.html>   (1995) The effects of AGGGAAGGGA pentanucleotide repeat on JC virus gene expression and the isolation and characterization of a cDNA encoding an AGGGAAGGGA binding protein.  Masters thesis, Memorial University of Newfoundland.

abstract: Human JC virus (JCV) is the etiologic agent of progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disorder of the central nervous system.  Although JCV is a widely-distributed polyomavirus and is oncogenic in animals, its strict dependence for viral growth and expression of JCV on human fetal glial cells has hindered detailed studies of the regulation of JCV early and late gene expression.  Previous reports have shown that gene expression of JCV is regulated by viral T antigen and cellular transactivating factors, such as NF1.  To date, several cellular factors regulating JCV early and late gene expression have been identified and isolated, and their binding site sequences or motifs in JCV DNA have been characterized. -- The AGGGAAGGGA pentanucleotide (penta) repeat motif of the JCV control region has been suggested to positively (stimulate) and negatively (inhibit) regulate JCV early and late gene expression.  A similar sequence that negatively regulates the expression of c-myc was also identified in the upstream region of the c-myc gene.  Several proteins ranging from 25 to 80 kDa have been identified which specifically interact with this penta repeat motif.  Among them, a 56 kDa protein has been suggested to act as a repressor for the JCV late gene expression and a 70 to 80 kDa protein has been shown to be required for the early gene expression.  Thus, there are several proteins interacting with this penta repeat motif and differentially regulating the JCV early and late gene expression.  Therefore, it would be very helpful to isolate and characterize such penta repeat motif binding proteins. -- To study the regulation by the penta repeat motif for JCV expression, I cloned JCV promoter-enhancer fragments containing mutated penta repeat motif into a CAT reporter plasmid and transfected the plasmid into P19 cells differentiated by retinoic acid into glial cells and U87MG human glioblastoma cells.  CAT assays showed that the pentanucleotide repeat motif within the JCV promoter-enhancer region upregulated JCV late expression and downregulated JCV early expression.  Mobility shift assays revealed two protein complexes specifically bound to the wild type penta repeat motif in both glial and nonglial cell extracts.  Two proteins of approximately 60 and 45 kDa were detected by UV crosslinking.  The penta repeat motif was then used to isolate a penta repeat motif binding factor by screening a cDNA expression library from retinoic acid-differentiated P19 glial cells.  One positive cDNA clone (RP1) was found to specifically bind to the penta repeat motif.  To characterize RP1, Southwestern blots with a β-galactosidase (β-gal) fusion protein indicated that this RP1 cDNA encoded the protein that specifically binds to the penta sequence.  Consistent with my mutation results, preliminary in vivo results showed that the protein encoded by this cDNA could negatively regulate JCV early gene expression.  The sequence of RP1 cDNA was found to contain sequences that were predicted to code for a protein containing seven putative zinc finger motifs in the carboxyl terminus two-thirds of the protein.  Based on my data and the results of others, I proposed a model for the interaction of RP1 with JCV penta repeat motif as a complex in glial and nonglial cells, suggesting that this interaction contributes to the glial cell specificity of JCV.  This model would involve RP1-penta acting in concert with other sites and factors in the JCV promoter-enhancer to prevent JCV gene expression in nonglial cells.


identifier: Gamberg, Jane C. <https://research.library.mun.ca/view/creator_az/Gamberg=3AJane_C=2E=3A=3A.html>   (1996) Post-fusion selection of antigen-specific hybridomas.  Masters thesis, Memorial University of Newfoundland.

abstract: The ability to create monoclonal antibodies has allowed great strides to be made in research and clinical medicine, and continues to contribute to progression in many areas.  However, the technology involved is labor-intensive and often inefficient.  A typical cell hybridization procedure will generate thousands of hybridomas, with the great majority being irrelevant.  Conventional technology requires maintenance and testing of the total population, in order to identify the very few hybrids that are secreting antibody of the desired specificity.  Particularly for antigens of low immunogenicity, this is clearly inefficient. -- The purpose of this study is to explore methods for selecting antigen-specific hybridomas soon after the fusion procedure.  This would eliminate the unnecessary maintenance of irrelevant hybrids, reducing much of the time, effort and materials that are currently consumed in this technology. -- For these fusions, transfectant cells expressing HLA-DP molecules were the immunogens.  Monoclonal antibodies recognizing DP polymorphisms were desired as serologic reagents, for matching donor-recipient pairs in bone marrow transplantation.  Fused cells were grown as bulk cultures and Ag-specific selection was attempted, using the antigen as a probe for hybridomas expressing specific immunoglobulin receptors.  Two methods were tested: immunomagnetism (by use of antigen-coated immunometallic beads), and panning (by use of the immunizing transfectant cells).  The yield of antigen-specific hybridomas was compared to that obtained in conventional fusions. -- The results indicate that panning, using the procedure outlined in this study, is not a useful method for selecting DP-specific hybridomas from a post-fusion bulk population.  Immunomagnetism, on the other hand, produced satisfactory results, offering a potentially useful way to increase the efficiency of monoclonal antibody generation.


identifier: Bagchi, Tamishraha <https://research.library.mun.ca/view/creator_az/Bagchi=3ATamishraha=3A=3A.html>   (1986) Subcellular compartmentalization of mRNAs.  Masters thesis, Memorial University of Newfoundland.

abstract: The importance of the cytoskeleton in protein synthesis was studied in differentiating L6 rat myoblasts.  Soluble and cytoskeletal fractions obtained after gentle, non-ionic detergent lysis of myoblasts and myotubes were analysed for the presence of ribosomes and mRNPs.  The role of the cytoskeleton in compartmentalization of specific mRNPs in myoblasts and myotubes was investigated. -- mRNPs in polysomal arrays were primarily associated with the cytoskeleton.  In addition, the cytoskeletal fraction also contained mRNA in the form of free mRNPs.  Therefore, the association of mRNA with the cytoskeleton did not seem to depend on the presence of ribosomes for attachment.  Furthermore, analysis of specific mRNAs in the various subcellular fractions of myoblasts and myotubes revealed differences in the distribution pattern of these mRNAs. -- The effects of depolymerizing the microfilaments with cytochalasin B in myoblasts, was investigated.  Treatment of myoblasts with cytochalasin B did not result in movement of ribosomes or specific mRNPs from the cytoskeletal fraction to the soluble fraction.  This indicates that in L6 myoblasts, ribosomes and mRNPs are not associated with microfilaments.  In addition, it was observed that cytochalasin B inhibited the incorporation of precursor into RNA and not protein.  The effect on RNA synthesis, however, was due to an inhibition of uptake of precursor uridine, which was found to be reversible.


identifier: Chowdhury, Badrul Alam <https://research.library.mun.ca/view/creator_az/Chowdhury=3ABadrul_Alam=3A=3A.html>   (1988) Prevention of cadmium induced immunopathology by zinc in mice.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: Cadmium is an ubiquitous toxic metal to which everyone is exposed at low levels. It is toxic to almost every organ system of the body including the immune system. In this study, the effects of a relatively low dose of cadmium on the immune system of mice and the effects of a moderately large dose of zinc on cadmium-induced immunopathology were studied. Six-week old C57BL/6 male mice were exposed to 50 ppm cadmium in drinking water for 3 weeks, and killed 0, 3 and 6 weeks after cessation of treatment. In some groups, 500 ppm zinc was added to the drinking water with or after cadmium treatment. The number of IgM and IgG antibody-forming cells in the spleen was higher in cadmium-treated mice as compared to non-treated controls at 0 week. Concurrent zinc administration prevented the enhancement of antibody-forming cell response. Proliferative response of spleen cells to the T cell mitogens phytohaemagglutinin and concanavalin A tended to be high in cadmium-treated mice and  zinc administration after exposure to cadmium tended to lower it. The number of CD8⁺ cells in the spleen was lower and the ratio of CD4⁺ to CD8⁺ cells, reflecting the balance of immunoregulatory T lymphocytes, was higher in cadmium treated mice. Concurrent zinc administration prevented the alteration of T cell subsets. Suppressor cell activity tended to be low in cadmium treated mice. Natural-killer cell activity in the spleen was low in cadmium treated mice and concurrent zinc treatment prevented the suppression. B cell count in the spleen and antibody production by splenic lymphocytes on pokeweed mitogen stimulation was not altered by cadmium or zinc treatment. Cadmium and zinc treatment had  no effect on liver, kidneys, spleen and thymus weights and lymphocyte content of spleen, thymus and peripheral blood. Use of immunofluorescence with anti-mouse IgG and complement  C3 showed no evidence of autoimmune reaction in kidney sections. On electron microscopic examination, ultrastructural alterations were seen in proximal tubular epithelial cells of the cadmium treated mice. Mitochondria were increased in number and the cisternae were distorted, and inside several cells electron dense materials were seen.  Liver and kidney cadmium concentrations were high in cadmium-treated mice as compared to non-treated controls. Tissue cadmium levels were lower in mice treated with both zinc and cadmium than in those treated with cadmium alone. The results suggest that a relatively low dose of cadmium exposure produces immune alterations in mice that can be prevented by a moderately large dose of zinc. -- INDEXING KEY WORDS: cadmium; zinc; cellular immunity


identifier: Toumishey, Laura Hope <https://research.library.mun.ca/view/creator_az/Toumishey=3ALaura_Hope=3A=3A.html>   (1978) Punishing the pregnant innocents : single pregnancy in St. John's, Newfoundland.  Masters thesis, Memorial University of Newfoundland.

abstract: The primary objectives of this study are to determine, from data obtained from 40 single pregnant girls in the city of St. John's, -- (a) to what extent social and emotional factors are inhibitory to a healthy pregnancy outcome for all persons concerned. -- (b) whether the established and generally accepted social norms for sex-related behavior are relevant to the attitudes and behaviour of young people living in St. John's today. -- The primary concerns of those interviewed, were closely related to their own perceptions of anticipated responses from significant others, i.e. parents, sexual partners and social groups etc.  Data analysis also served to identify significant emotional milestones along the route to, and during an illegitimate pregnancy. -- A discussion of the role and responsibility of any society, mainly through use of the family, to prepare its youth for future sex relationships, motherhood and parenthood revealed that, in reality, there were serious discrepancies, irrelevancies and serious shortcomings in attitudes and programming within the existing and generally accepted socialization process. -- A breakdown of this process served to better isolate and identify the level of "educational" input provided for each of three major age groups.  These were pre-puberty, early adolescence and young adulthood.  A fourth group, single pregnant women, was then discussed to determine if the process, so described, plus the existing programming and services currently provided in this community were sufficiently adequate to (a) ensure the conformity of today’s youth to the established sex-related behavioral norms and (b) provide for the re-entry, without social and emotional jeopardy of those who inadvertently, temporarily, and sometimes deliberately, deviate from these norms. -- Grounded Theory as described by Glaser and Strauss (1967)¹ was used to generate a formal theory called - Punishing the Pregnant Innocents.  The extent to which specific punishments are imposed upon these "social deviants" are described in this study.  The question is raised as to whether such punishments are justified or are they in response to a sense of frustration over the inability of society to prepare, control and appropriately direct the sex-related behavior of its youth. -- Recommendations for changes in social attitudes and approaches to the problems associated with illegitimate pregnancies in the city of St. John's, are included.  These are suggested in the hope that they may contribute in the alleviation of the physical, social and emotional traumas too often experienced by these pregnant young women and their children. -- ¹Glaser, B.G., Strauss A.  The Discovery of Grounded Theory: Strategies for Qualitative Research, Aldine Publishing Co., Chicago, 1967.


identifier: Osborne, Perry Alonzo <https://research.library.mun.ca/view/creator_az/Osborne=3APerry_Alonzo=3A=3A.html>   (1996) Purification and characterization of mouse bispecific monoclonal antibodies recognizing carcinoembryonic antigen (CEA) and doxorubicin.  Masters thesis, Memorial University of Newfoundland.

abstract: Bispecific hybrid-hybridomas have been developed previously from an anti-carcinoembryonic antigen (CEA) hybridoma (11-285-14) and spleen cells from mice inoculated with doxorubicin-bovine serum albumin (DOX-BSA) conjugate. Seven hybrid-hybridomas were selected on the basis of binding to both CEA and DOX. The purpose of this study was to purify and characterize these antibodies. -- Each hybridoma was separately injected into Balb/c mice intraperitoneally and ascitic fluid collected. The pooled fluid was then Protein A  affinity purified and then further purified using an hydroxylapatite, high performance liquid chromatography (HPLC) column. Fractions from HPLC separations were tested using various enzyme linked immunosorbent assays in order to  determine the location of the bispecific antibodies. Positive fractions were pooled and used in microcytostasis assays using the high CEA expressing (SKC01) and low CEA expressing (COLO 320 DM) cell lines. One particular hybridoma (26-61-10) was selected for these in vitro assays.  The bispecific antibody ⁴ DOX test was able to significantly  decrease the IC₅₀ of DOX with SKCOI. The IC₅₀ with the COLO 320 DM was not altered, illustrating the specificity of the bispecific antibody for a CEA expressing cell line. The specificity of the results were confirmed when DOX was used in conjunction with a non-specific antibody (Ag8). Bispecific antibody on its own or control antibody on its own, did not have a significant effect on the viability of the cell lines. This supported the theory of the bispecific antibody delivering the drug directly to the CEA expressing cancer cells and that the increased toxicity was not due to direct antibody killing of cells. -- These results provide the first demonstration that the drug doxorubicin can be targeted to a colonic cancer cell line expressing CEA by a bispecific antibody recognising CEA and the drug.


identifier: Venkatakrishnan, Annapurna <https://research.library.mun.ca/view/creator_az/Venkatakrishnan=3AAnnapurna=3A=3A.html>   (1990) Pseudocholinesterase and its relationship to serum lipoproteins in diabetes mellitus.  Masters thesis, Memorial University of Newfoundland.

abstract: The activities of pseudocholinesterase (PChE) were compared in the serum of type I and type II diabetic patients and non-diabetic subjects.  Both type I and type II diabetic patients showed increased serum PChE activity concomitant with the presence of hyperlipidemia.  Pearsons correlation analysis showed a positive correlation between triglycerides (TG) and PChE in both type I (P=0.499) and type II (P=0.526) diabetic patients. -- Induction of chemical diabetes in rats with Streptozotocin (SZ) and alloxan also increased the serum PChE activity which paralleled the development of diabetes mellitus.  Serum triglycerides, apo-B containing lipoproteins (total low density lipoproteins TLDL) and glycerol concentrations also increased.  When the hyperglycemia produced in streptozotocin induced diabetic rats was controlled by administration of insulin, the levels of TG, glycerol and PChE activity all reverted to pre-diabetic levels.  When insulin treatment was withdrawn hyperglycemia developed again and serum levels of PChE activity, TG, glycerol and TLDL also increased.  The concentration of TG in the liver of SZ-diabetic rats was significantly higher compared to the normal rats.  Adipose tissue and liver PChE activity were not significantly different in these SZ-diabetic rats. -- Gold thioglucose (GTG) treated mice, which are type II diabetic models, also showed a significant increase in serum PChE activity and lipids similar to the SZ induced type I diabetic models.  Inhibition of PChE activity in GTG treated mice was associated with a decrease in serum glycerol, TG and TLDL levels.  Liver PChE activity was markedly higher in the GTG treated mice compared to the untreated control mice.  Administration of Iso-OMPA to GTG treated mice inhibited both liver and adipose tissue PChE activity. -- Heparin treatment of SZ-diabetic rats significantly reduced serum TG levels without affecting PChE activity, cholesterol, HDL-C or TLDL levels. -- Administration of Iso-OMPA, a specific PChE inhibitor, to SZ-diabetic and normal rats produced a significant reduction in serum TG, glycerol and TLDL levels.  Withdrawal of iso-OMPA inhibition in the diabetic rats resulted in an increase in the lipid levels to those previously present in the diabetic state.  PChE activity and TG levels were also reduced in the iso-OMPA treated diabetic and normal rat livers compared to the untreated rats.  Adipose tissue PChE activity was also inhibited in the iso-OMPA treated diabetic and normal rat. -- Inhibition of PChE activity with iso-OMPA failed to produce an accumulation of choline or cholinesters in the liver, serum or to affect their excretion in the urine of normal rats. -- The results indicate that changes in PChE activity parallel changes in TG metabolism, particularly during the perturbances that accompany diabetes mellitus.  Whether PChE has a role in very low density TG (VLDL-TG) metabolism remains to be determined but is of considerable interest.


identifier: Hasnadka, Raghuram V. <https://research.library.mun.ca/view/creator_az/Hasnadka=3ARaghuram_V=2E=3A=3A.html>   (1995) The role of ACTGCT motif in the expression of the minimal constitutive enhancer of the human papillomavirus type 18 in C33A cervical carcinoma cells.  Masters thesis, Memorial University of Newfoundland.

abstract: The activity of the human papillomavirus type 18 minimal constitutive enhancer (nucleotides 7508-7738) was studied in  C33A cervical carcinoma cells . Unidirectional deletion mutations were performed to delineate the minimal constitutive enhancer (MCE) region that is important for the  human papillomavirus type 18 expression. Maximum reduction in the activity was seen when region V (nucleotides 7673-7738) was deleted. The deletion mutant enhancer pBK8315 (nucleotides 7508-7664) expressed only 6.5 percent of the full length MCE activity. Though the expression was the least with this mutant, all the regions appeared to be a requirement for the full activity of the MCE. Gel retardation assays with the full length MCE using C33A nuclear extract showed two complexes. Gel retardation assays  were performed with deletion mutants having regions I-IV (nucleotides 7508-7664) and region V using C33A nuclear extract. The slower migrating complex associated with regions I-IV, while the faster migrating complex was bound to region V. To identify the important motif of region V and  thereby the factor responsible for the expression, site directed mutagenesis was performed. The ACTGCT motif at nucleotides 7679-7684 was mutated. The in vivo activity of this site-directed mutant plasmid pBBl55 was reduced to the extent similar to pBK8315, signifying the importance of this  motif in the context of the full length MCE. When gel retardation assay was performed with the site-directed mutant using C33A nuclear extract, the faster migrating complex was abolished, while the slower migrating complex was present. The mutant MCE competed with the slower migrating complex, while the faster migrating complex was still present. The in vitro binding assays correlated with the in vivo activity in C33A cells. To further investigate the binding property of the mutant motif, UV crosslinking was performed using C33A nuclear extracts with MCE sequences  from nucleotides 7667-7693. A band present with the wild type sequence was absent when the mutant sequence was used in the reaction. These experiments demonstrate the importance of the ACTGCT motif at nucleotides 7679-7684 and suggest the involvement of an ACTGCT binding protein (ABP) in the regulation of HPV 18 MCE activity.


identifier: Power, Roberta Patricia <https://research.library.mun.ca/view/creator_az/Power=3ARoberta_Patricia=3A=3A.html>   (1993) The role of capsaicin-sensitive neuropeptides and the intrinsic cardiac ganglia on cardiodynamics and atrial natriuretic peptide (ANP) release.  Masters thesis, Memorial University of Newfoundland.

abstract: Atrial natriuretic peptide (ANP) is a circulating hormone, released from the heart, whose natriuretic and diuretic actions play an important role in cardiovascular homeostasis. It is stored as a prohormone in cardiac myocytes and converted to a circulating form upon release from the myocytes. Numerous factors have been shown to modulate ANP release, however the principal stimulus for release is believed to be stretch of the atrial wall. -- Recently it has been demonstrated that the capsaicin-sensitive peptidergic innervation of the rat heart, namely the substance P (SP) and calcitonin gene-related peptide (CGRP) fibers, is a component modulating the release of immunoreactiveANP (irANP). This research project initially investigated the role of the intrinsic cardiac ganglia on cardiodynamics and irANP release. In Sprague-Dawley rats, in  vitro electrical stimulation of epicardial regions dense with cardiac ganglia (50Hz, 15-20μs, 4μA delivered in 5s trains), referred to as 'ganglionic' stimulation, resulted in a dramatic decrease in heart rate followed by a transient  period of tachycardia. Cardiodynamic effects were accompanied by a significant increase in irANP release. Results from stimulation of epicardial regions lacking the presence of cardiac ganglia, termed 'non-ganglionic' stimulation indicated that heart rate changes were attributable to excitation of particular components of the ganglia at the site of stimulation, and not simply to spread  of an electrical current over the epicardium. -- Also investigated were the effects of neonatal capsaicin treatment (capsaicin is a chemical that abolishes SP and CGRP cardiac innervation in rats when administered neonatally) on irANP release in the model of cardiac ganglia  stimulation and in other models previously demonstrated to release irANP, such as stretch of the right atrium. In ganglionic stimulation experiments, release of irANP was independent of changes in heart rate. The presence of innervation by immunoreactive SP and CGRP was shown to be imperative for significant increase in irANP release after ganglionic stimulation and after stretch of the right atrium. -- Pharmacological studies were carried out to gain insight into the role of acetylcholine and noradrenaline in the biphasic change in heart rate and release of irANP after  ganglionic stimulation. The initial decrease in heart rate was shown to be associated with parasympathetic innervation and similarly, tachycardia was associated with sympathetic innervation. However, release of irANP was demonstrated to be independent from either decreases or increases in heart rate. It is hypothesized that if SP and CGRP innervation are   involved in irANP release, and if capsaicin depletes these peptides, then an acute treatment of capsaicin should release stores of SP and CGRP and yield an increased release   of irANP. This was the case when vehicle-treated animals were administered an acute dose of capsaicin, however the tissues from animals treated neonatally with capsaicin showed no release of irANP. Acute capsaicin administration had no effect on heart rate in either group. -- Finally, Northern blot analysis of ANP messenger ribonucleic acid (mRNA) production was performed to ascertain if neonatal capsaicin treatment was affecting synthesis of ANP and if levels of mRNA expression were equivalent in vehicle- and capsaicin-treated animals. -- It was concluded that electrical stimulation of the intrinsic cardiac ganglia results in a biphasic change in heart rate associated with the sympathetic and parasympathetic cardiac innervation. Also, in the models used here, the SP and CGRP cardiac innervation seem responsible for the modulation of the release of irANP. Some preliminary data also suggest that SP  and CGRP may be modulating irANP release in in vivo models of atrial pacing as well. Further studies are necessary before conclusions can be drawn regarding the effects of capsaicin on ANP synthesis. -- KEY WORDS and PHRASES: atrial  natriuretic peptide; electrical stimulation of cardiac ganglia; atrial stretch; atrial pacing; substance P; calcitonin gene-related peptide; mRNA for ANP


identifier: Jacobs, Frederik Andre <https://research.library.mun.ca/view/creator_az/Jacobs=3AFrederik_Andre=3A=3A.html>   (1985) Regulation of ribosome biogenesis during myogenesis of rat myoblasts.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: The ribosome is an organelle which translates the genetic information provided by the nucleus into proteins.  Because of its central role in gene expression, the production of the numerous ribosomal components must be coordinated for the efficient assembly of the ribosome so that it may perform effectively.  The rat-derived muscle cell line L6-5 provides an excellent system in which to study ribosome biogenesis since, after terminal differentiation, ribosome accumulation rates are much reduced. -- The synthesis rates of rRNA and ribosomal proteins (r-proteins) were investigated in proliferating L6-5 myoblasts and terminally differentiated myotubes.  The rRNA and r-proteins were coordinately produced in myoblasts, with little detectable turnover of the individual components.  In myotubes, however, the rate of rRNA synthesis was reduced by approximately 75% while the r-proteins continued to be synthesized at levels near those observed for myoblasts.  The production of rRNA and r-proteins, which was coordinate in myoblasts, became uncoupled in myotubes. -- Various possible explanations of the uncoupling of rRNA and r-protein production in myotubes were explored.  It was determined that the levels of the r-protein mRNA’s (rp-mRNA's) were similar in myoblasts and myotubes, suggesting that their translational efficiencies were unaltered by terminal differentiation.  It therefore appeared that the rate of r-protein synthesis was determined by cellular rp-mRNA levels. -- To ascertain whether altered rp-mRNA metabolism accounted for the uncoupling of r-protein and rRNA synthesis in myotubes, the half lives of the rp-mRNA's were measured.  The results reveal that the stability of rp-mRNA’s were similar in myoblasts and myotubes, with half lives of approximately 11 hours.  The data indicate that the rate of r-protein synthesis was regulated at the level of r-protein gene transcription, which suggests that rRNA and r-protein production was uncoupled at the transcriptional level in myotubes. -- The uncoupling of rRNA and r-protein gene transcription in myotubes was demonstrated by measuring their transcription rates in vitro.  It was determined that rRNA genes in myotubes were transcribed at approximately 30% of the rate found in myoblasts when compared to rp-mRNA genes.  These results directly demonstrated the differential expression of these two gene families in L6-5 cells.  The implications of these findings with respect to the regulation of ribosome biogenesis and myogenesis are discussed.


identifier: Brown, Sandra A. <https://research.library.mun.ca/view/creator_az/Brown=3ASandra_A=2E=3A=3A.html>   (1991) Testosterone masculinizes the development of the substance P-immunoreactive innervation of the rat limbic forebrain.  Masters thesis, Memorial University of Newfoundland.

abstract: Marked sex differences in the substance P-immunoreactive (SPir) innervation of the most posterior divisions of both the medial nucleus of the amygdala (MEPD) and medial bed nucleus of the stria terminalis (BSTMP) have recently been described in adult rats.  The present study has examined the effects of early postnatal testosterone exposure on the development of the SPir innervation of these regions and on certain cell groups within the medial amygdala and the BSTMP.  Four groups of animals (n=4/group) were compared.  Males were either gonadectomized (GM) or sham-operated (SM) on day 1, while females were injected subcutaneously with either vehicle (SF) or 500 ug testosterone propionate (TF) on days 2 and 5.  All animals were killed before puberty at day 27.  Alternate sections were either stained with cresyl violet or for SP using the peroxidase-anti-peroxidase method.  The areas of dense SPir fiber staining and of relevant cell groups (cresyl staining) were measured using a microcomputer-based image analysis system. -- Marked sex differences were seen in the medial amygdale and medial posterior bed nucleus before puberty.  The areas of the discrete, darkly-staining fields of SPir fibers in MEPD (MEPD-SP) and in the most medial part of BSTMP (BSTMPM-SP) were larger in sham males than in sham females, as they are in adults.  The cell groups MEPD, BSTMP, and the lateral division of BSTMP, BSTMPL, were also significantly larger in sham males than in sham females.  The early postnatal treatments completely reversed these sex differences for features of the BSTMP, i.e. measures from groups SM and TF were similar and larger than measures from groups SF and GM which were also similar.  Similar results were seen for the sexually dimorphic features of the amygdala, MEPD and MEPD-SP.  The areas of these features were not significantly different in groups SF and GM and were smaller than in groups SM and TF.  However, these features were larger in group SM than in group TF.  Thus injecting newborn females with testosterone did not completely masculinize MEPD and MEPD-SP.  Unexpectedly, it was also found that certain features of the medial amygdala and medial bed nucleus were larger in the left than in the right hemisphere. -- The sex differences described here are consistent with the results of recent studies which describe a sexually dimorphic system of heavily interconnected cell groups which includes the vomeronasal olfactory pathway, the most posterior parts of the medial amygdala and medial bed nucleus, and the medial preoptic nucleus.  These regions have been implicated in the regulation of a number of sexually differentiated brain functions in the rat.  The present data are important because they suggest that SPir neurons form an important part of this sexually dimorphic circuitry, and demonstrate that these sex differences are present before puberty.


identifier: Woolgar, Jane R. (Jane Ruth) <https://research.library.mun.ca/view/creator_az/Woolgar=3AJane_R=2E_=28Jane_Ruth=29=3A=3A.html>   (1988) The development and interaction of catecholaminergic and peptidergic perivascular nerve fibres in the rat mesenteric vascular bed.  Masters thesis, Memorial University of Newfoundland.

abstract: The hypothesis that different fibre systems interact during the development of innervation of the mesenteric vascular bed was examined.  It is proposed that this interaction may be essential to the development of each innervating system and in turn affect the development of the vasculature.  Immunohistochemistry was used to allow differentiation of different fibre types.  Electron microscopy was used to determine relationships between axons.  Although it is still premature to draw a final conclusion, the results of the present studies suggest that peptide-containing and noradrenergic nerves follow different patterns of development and that they interact during development.  It appears as if peptidergic innervation limits the proliferation of catecholaminergic fibres, whereas catecholaminergic fibres are necessary for the full development of peptidergic fibres.  The peptidergic fibres are normally found in large bundles whereas the catecholaminergic fibres are found in small bundles.  A mixing of these catecholaminergic and peptidergic fibres can occur.  Colocalization of peptidergic and catecholaminergic substances in the same fibre also appears to be possible.


identifier: Howlett, Susan E. <https://research.library.mun.ca/view/creator_az/Howlett=3ASusan_E=2E=3A=3A.html>   (1982) The mechanical and histochemical characteristics of an in vivo nerve-muscle preparation of normal and dystrophic avian muscle : effects of sex, disease and age.  Masters thesis, Memorial University of Newfoundland.

abstract: An in vivo nerve-muscle preparation of the posterior latissimus dorsi muscle (PLD) has been used extensively to study contractile, pharmacological and electrophysiological characteristics of avian muscles affected by hereditary muscular dystrophy.  The use of the preparation is limited since there is no convenient artery for cannulation to assess the acute effects of substances of potential therapeutic value.  A preparation that appears to meet this requirement, the extensor digitorum communis (EDC) muscle preparation, is developed in the present study.  The mechanical and histochemical characteristics of the EDC muscle compare favorably to those reported for normal and dystrophic avian muscle in the PLD preparation. -- The gene for muscular dystrophy in chickens is thought to be autosomal recessive but personal observations and communications with some workers in the area suggest that the gene is expressed differently in males and females.  The mechanical characteristics of the EDC muscle have been examined in old and young groups (old = greater than 6 months; young = 6-9 weeks) of normal and dystrophic chickens with respect to sex.  Results showed that age-related sex differences were apparent for mechanical parameters known to distinguish normal and cystrophic birds, that is ability to rise from the supine position, wing apposition score, post-tetanic potentiation, twitch-tetanus ratio and post-tetanic contracture.  The sex differences observed in young birds indicate that the females were more severely affected by the disease than were the males.  In the older birds the contractile responses of the EDC in males showed classic signs of dystrophy while females were often not significantly different from normal.  If the inheritance pattern is truly autosomal recessive then perhaps there is an endogenous "protective" factor in the mature female.  It is suggested that the lowered plasma cholesterol in the egg laying hen could account for the observed sex differences.  Defects have been reported in a variety of membranes in human and animal muscular dystrophies.  Since cholesterol is known to decrease membrane fluidity and since increases in plasma cholesterol have been reported in dystrophic chickens, a dramatic decrease in plasma cholesterol could perhaps improve the dystrophic condition.


identifier: Gillespie, Mona English <https://research.library.mun.ca/view/creator_az/Gillespie=3AMona_English=3A=3A.html>   (1989) Waiting list analysis of a tertiary care hospital.  Masters thesis, Memorial University of Newfoundland.

abstract: The research for this thesis has 2 components; a descriptive analysis of the waiting list for a tertiary care hospital for the fiscal year, 1983/84, and a chart review of patients who were admitted to hospital after being on the waiting list for extended time periods. -- For the descriptive analysis of the waiting list, 3,275 cases were analyzed.  2,886 of the cases were admitted to hospital.  The median wait time for those patients was 9 days.  There were variances in waiting time for different medical services.  At the end of the study period 589 patients remained on the waiting list.  51 percent of those had waited longer than 3 months for admission. -- The chart review was conducted on the most frequent occurring diagnoses in the services of orthopaedics, neurosurgery and cardiovascular surgery.  Patients in this review had waited 0 - 30 days, 30 - 90 days and 90+ days for admission.  Criteria were used to determine differences, if any, in the process of care during hospitalization for the patients admitted with the selected diagnoses. -- The results of the analysis showed a difference for one criteria only, length of stay was longest across the three groups for those who waited 30-90 days.


identifier: Edwards, Alison Christine <https://research.library.mun.ca/view/creator_az/Edwards=3AAlison_Christine=3A=3A.html>   (1992) Validity of self-reported medical care utilization.  Masters thesis, Memorial University of Newfoundland.

abstract: The objective of this thesis was to study the validity of self-reported medical care utilization.  Hospitalization and physician visit data for a twelve month recall period were obtained from both an interview and official records.  The self-reported information was collected by a telephone survey applied to all adults over 20 years of age in a probabilistic sample of households in metropolitan St. John's (3,300 subjects, 85% response rate).  Verification data were later obtained for 2,994 subjects (91%) from the provincial hospitalization database and health insurance plan. -- The utilization data were used to categorize the subjects into those in agreement, the underreporters and the overreporters.  A variable denoting level of accuracy was derived.  Socio-demographic variables (sex, age and education) and health status variables (self-assessed health status, number of chronic conditions, satisfaction with physical health, and emotional status) were used in a descriptive analysis to compare those in  agreement, the under- and overreporters. -- Logistic regression was utilized to investigate the probabilities of being in disagreement on utilization and to compare those who were accurate in self-recall with those who were not. -- The analyses showed that most subjects (97.3%) were in agreement on hospitalizations in the recall period whereas 84.1% agreed on physician visits.  The observed rates of overreporting were 16.2% for hospitalizations and 9.7% for physicians, and for underreporting, 7.3% for hospitalizations and 10.0% for physicians. -- For hospitalizations, 1) subjects in disagreement had, usually, less education and more chronic conditions than those in agreement, 2) underreporters tended to be older than either overreporters or those in agreement, and 3) the less accurate at reporting were generally more likely to report several chronic conditions, fewer years of education, lower emotional and self-assessed health status and were older. -- For physician visits, 1) subjects found to be in disagreement were in general male, had better emotional and self-assessed health status, and reported fewer chronic conditions, 2) underreporters tended towards higher self-assessed health status, lower education and fewer chronic conditions than those in agreement, and 3) those more prone to be inaccurate in reporting the number of visits were generally female, had lower self-assessed health status, were less educated and had more chronic conditions.


identifier: Payne, Shawn <https://research.library.mun.ca/view/creator_az/Payne=3AShawn=3A=3A.html>   (1994) Variability of TNF-α secretion by peripheral blood mononuclear cells from healthy males.  Masters thesis, Memorial University of Newfoundland.

abstract: Tumor necrosis factor-α (TNF-α) is a cytokine with inflammatory and regulatory properties produced by monocytes  and activated T-cells. Levels of TNF-α secretion in vitro by peripheral blood mononuclear cells (PBMC) stimulated with bacterial lipopolysaccharide (LPS) orphorbol 12-myristate 13-acetate (PMA) plus concanavalin A (ConA) have been reported to vary among individuals and to be associated with  HLA-DR alleles, namely HLA-DR2 with low levels of TNF-α secretion and HLA-DR3 and DR4 with high levels. -- In this study we have measured levels of TNF-α secreted by LPS-stimulated PBMC from 72 healthy young males. There was a large degree of variation in the level of secreted TNF-α and  this interindividual variation was relatively stable in four  individuals tested 2 to 4 times. The study panel was also typed for HLA-DR, -A, -B and -C antigens. A weak association  was shown between HLA-DR3 and low levels of TNF-α secretion (p = 0.014, uncorrected). No association was shown between levels of TNF-α secretion and HLA-DR2, -DR4 or HLA-B antigens. -- We further explored the possibility that differences in levels of TNF-α secretion might be due to (1)  individual differences in the kinetics of TNF-α secretion and/or (2) differences in the relative number of TNF-α secreting cells when different stimulants were used. The kinetics of 20μg/ml LPS-induced and 1ng/ml LPS-induced TNF-α  secretion by PBMC were very similar but the total amounts secreted were higher with 20 μg/ml LPS. The kinetics of TNF-α secretion were quite different when PBMC were stimulated by LPS or ConA plus PMA. LPS-induced TNF-α peaked at 3 to 6 hours while ConA/PMA-induced TNF-α secretion did not reach an obvious peak in our experiments but was low at 3 hours and continued to rise at 53 hours. Five individuals were classified as high to low secretors using the 3-hour, 20 μg/ml LPS, stimulation protocol. This classification changed  dramatically when the ConA/PMA, 53-hour protocol was used and three individuals classified high became low or vice versa. This is an important observation and must be considered when investigating associations between levels of  TNF-α secretion and HLA antigens. -- To investigate if differences in secretion might be due to individual differences in the number of TNF-α secreting cells, a two-color immunofluorescence assay was developed to monitor cell  phenotype and cytoplasmic TNF-α by flow cytometry. There was  no consistent relationship between the proportion of CD14 monocytes in the samples staining positive for cytoplasmic TNF-α and the levels of secreted TNF-α by LPS-stimulated PBMC from two individuals tested, but this may have been due  to technical difficulties. However, differential counts of the male study panel PBMC samples by flow cytometry for the subsets CD14 monocytes, CD4 T-cells, CD8 T-cells and CD45RO T-cells showed no correlation between the relative numbers of cells in each subset and secreted TNF-α levels.


identifier: Oake, Elizabeth Ann <https://research.library.mun.ca/view/creator_az/Oake=3AElizabeth_Ann=3A=3A.html>   (1991) Validation and reliability-testing of a breakfast-eating survey instrument.  Masters thesis, Memorial University of Newfoundland.

abstract: The short-term consequences of breakfast omission entail physiological, psychological and cognitive alterations in some children.  Errors in school achievement tests and attention-maintenance tasks increase over the morning hours if breakfast is omitted.  Physiological manifestations of fasting include lowered blood glucose levels and a decrease in work capacity. -- Behavioural decrements in the child who skips breakfast are similar to those of the hungry child: irritability, listlessness and social isolation are often present.  The sociology of hunger suggests that breakfast-skipping and other negative environmental factors which impact on the child may ultimately result in school failure. -- Methods of obtaining accurate information of food intake in the young elementary school child have usually incorporated the parent (mother) as a surrogate respondent, despite evidence showing that children are accurate reporters of their own intake in terms of types of foods eaten, but not necessarily quantities of food consumed. -- This study examined the validity and reliability of a breakfast-eating questionnaire assessed on a convenience sample of elementary school children enrolled in grades 1, 2 and 3 in the Halifax-Dartmouth area.  The questionnaire made use of symbols to avoid problems associated with limited reading ability present in this age group.  The validated instrument will be used to obtain information about breakfast habits from children in grades 1, 2 and 3, residing in Nova Scotia. -- Key words: breakfast; children; questionnaire; reliability; validity; cognition; recall.


identifier: Patel, Ashwinkumar <https://research.library.mun.ca/view/creator_az/Patel=3AAshwinkumar=3A=3A.html>   (1986) Pharmacological characterisation of calcium channels in vascular smooth muscle from hypertensive and normotensive animals.  Masters thesis, Memorial University of Newfoundland.

abstract: A consistent feature of hypertension is an increase in peripheral vascular tone which is ultimately controlled by intracellular calcium levels. Over the past decade, evidence  has emerged indicating an abnormality in ion handling by vascular smooth muscle as a possible cause of the elevated vascular tone. Various lines of evidence have led to the suggestion that there is an increased calcium influx in hypertension. The present work attempted to characterise calcium influx through receptor operated (ROC) and potential  operated channels (POC) in tail artery from SHR and WKY rats, using nifedipine, a calcium antagonist, as a probe. -- Potassium induced responses, were significantly more sensitive to nifedipine than norepinephrine responses in both SHR and WKY. However there was no difference in sensitivity to nifedipine, of either potassium or norepinephrine responses, between SHR and WKY at both ED₁₀₀ or ED₅₀ levels of stimulation. These results suggest a normal role for POC and ROC function in SHR animals. -- The calcium sensitivity of the vessels was higher in SH rats when activated by ED₅₀ levels of norepinephrine but not potassium, suggesting ROC alteration. The study also suggest  that submaximal (ED₅₀) levels of agonists should be used, in addition to ED₁₀₀ doses of agonists. Low concentrations of nifedipine (0.05nM) significantly reduced calcium sensitivity in potassium (ED₁₀₀) activated arteries from SH, but not WKY rats. Higher concentrations of nifedipine were required to significantly reduce calcium sensitivity in norepinephrine activated vessels from both SHR and WKY. Maximal calcium responses in norepinephrine (ED₁₀₀) activated  SHR vessels were more resistant to nifedipine than WKY vessels. These results suggest alterations in POCs and ROCs. -- No differential sensitivity to nifedipine was found in young 'prehypertensive' (5 week old) animals. At the 10-12 week age group, SH rats were more sensitive, compared to WKY, at high doses of nifedipine. Wistar normotensive rats were more insensitive to nifedipine than WKY rats. Surprisingly the differential sensitivity, to nifedipine, between SHR and WKY was reduced at the 20 week age group. These results suggest that enhanced calcium influx may not precede development of high blood pressure. As blood pressure increases calcium influx may sustain the high vascular tone, although direct evidence is still lacking. -- Collectively the results presented provide further indirect,  evidence for altered calcium channel function in hypertension.