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Biomedical subjects

M Miller

Publications and source records attributed to M Miller.

At least 253 records · Page 14Linked to original sources
PubMed1998

Social network characteristics as mediators in the relationship between sexual abuse and HIV risk.

Recent research suggests that sexual abuse may be a potent risk factor for engaging in HIV risk behaviors for women. This relationship is likely mediated by the long term sequelae of sexual abuse. One plausible causal pathway posits that specific social network characteristics increase HIV risk exposure opportunities. This is premised on the belief that previous sexual abuse predisposes some women to become members of risk networks characterized by deviant behaviors and that HIV risk occurs in the context of these networks. One hundred and thirty women opiate users were systematically recruited from methadone maintenance and syringe exchange programs in New York City. The women participated in a one hour interview and provided information on drug use and frequency, HIV drug and sex risk behaviors, social network characteristics, and sexual abuse histories. Univariate and logistic regression techniques were used to test the relationship between sexual abuse and increased HIV risk as mediated by social network characteristics. Previous sexual abuse was strongly related to all social network characteristics examined. Moreover, these network characteristics appeared to affect patterns of drug use in identifiable ways. Social isolation was the only network characteristic associated with both HIV drug and sex risk behaviors. However, although a history of sexual abuse was significantly associated with five of the seven specific HIV risk behaviors examined, the relationship between sexual abuse and HIV risk behaviors remained unchanged when social network characteristics were included in the statistical model. Overall, the results suggest that a sexual abuse experience or its aftermath influence behavior far into the future. However, the results of this study did not show social network characteristics mediating the relationship between sexual abuse and HIV risk. Rather, previous sexual abuse and social network characteristics appear to be independent contributors to HIV risk behaviors for women.

Adult↗
PubMed1998

Normal triglyceride levels and coronary artery disease events: the Baltimore Coronary Observational Long-Term Study.

OBJECTIVES: This study sought to evaluate long-term predictors of coronary events in men and women with arteriographically defined coronary artery disease (CAD). BACKGROUND: There is conflicting evidence of the role of triglycerides (TGs) as a prognosticator of CAD, and no studies have examined the long-term outcome of "normal" levels in predicting new coronary events. METHODS: This was a retrospective cohort study that evaluated 740 consecutive patients presenting for diagnostic coronary arteriography between 1977 and 1978. Beginning in 1988, patients with arteriographic CAD (n=350) were recontacted and asked to complete detailed medical questionnaires. Case and control patients were stratified by development of new coronary events, including death from ischemic heart disease, nonfatal myocardial infarction and revascularization. RESULTS: There were 199 events during the 18-year follow-up period. The mean high density lipoprotein cholesterol (HDL-C) was significantly lower (35 vs. 39 mg/dl; p=0.002) and TGs higher (160 vs. 137 mg/dl; p=0.03) in case patients than in control patients; After adjusting for age, gender and beta-adrenergic blocking agent use, multiple logistic regression analysis revealed the following independent predictors of CAD events: diabetes mellitus (relative risk [RR] 2.1, 95% confidence interval [CI] 1.4% to 3.1%), HDL-C <35 mg/dl (RR 1.5, 95% CI 1.1% to 2.00) and TGs >100 mg/dl (RR 1.5, 95% CI 1.1% to 2.1%). A Kaplan-Meier analysis revealed significantly reduced survival from CAD events in patients with baseline TG levels > or = 100 mg/dl compared with TG levels <100 mg/dl (p=0.008). CONCLUSIONS: TG levels previously considered "normal" are predictive of new CAD events. The cutpoints established by the National Cholesterol Education Program for elevated TGs (>200 mg/dl) may need to be refined.

Coronary Disease↗
PubMed1998

Effects of peroxide on the fluorescence of the Ca2+ probe Fluo 3 and the pH probe BCECF.

Fluorescence probes are invaluable tools in monitoring intracellular ion concentrations. They have also been used for studying how reactive oxygen species alter these concentrations and yet there are no studies indicating how reactive oxygen species directly affect the characteristics of the probes. Our concern was that if reactive oxygen were to affect characteristics of these probes, these measurements would be inconsequential. Therefore, we examined the effects of peroxide on the Ca2+-sensitive dye Fluo 3 and the pH sensitive dye BCECF. Peroxide concentrations below 10 mM did not alter fluorescence or binding characteristics of either dye. Since the concentrations of peroxide used in most pathophysiological experiments are in the micromolar range, we conclude that these probes are appropriate for monitoring the effects of peroxide on intracellular ion concentrations.

Aniline Compounds↗
PubMed1998

Determinants of rifabutin-associated uveitis in patients treated with rifabutin, clarithromycin, and ethambutol for Mycobacterium avium complex bacteremia: a multivariate analysis. Canadian HIV Trials Network Protocol 010 Study Group.

Uveitis occurred in a substantial proportion of AIDS patients receiving rifabutin, 600 mg daily, together with clarithromycin and ethambutol for treatment of Mycobacterium avium complex bacteremia. A case-control study was undertaken to examine potential risk factors for developing uveitis. Of eight parameters examined, only baseline body weight predicted the development of uveitis by both univariate and multivariate analyses (P = .001). The incidence of uveitis was 14% in patients weighing >65 kg, 45% in patients between 55 and 65 kg, and 64% in patients <55 kg. Concomitant therapy with fluconazole, a drug known to raise serum rifabutin concentrations, was not associated with an increased incidence of uveitis. The risk of uveitis was markedly reduced when rifabutin was given at 300 mg daily in combination with clarithromycin and ethambutol.

AIDS-Related Opportunistic Infections↗
PubMed1998

Tuberculosis, hepatitis B, rubella, rubeola, and varicella infection and immunity among medical school employees.

OBJECTIVE: To assess baseline health status of a medical school employee population and to assess this population's acceptance of vaccination and other interventions to reduce risk of disease transmission. DESIGN: A retrospective review of an employee health records database for a 4-year period. SETTING: A large, urban university hospital. PARTICIPANTS: 5,007 employees screened by employee health for immunity to vaccine-preventable illnesses and tuberculosis. RESULTS: 9.4% of the employees had positive tuberculin skin tests, with a conversion rate of 6.4% for those who had negative tests within the previous 2 years. Two individuals were identified who had active pulmonary tuberculosis. Fewer than 10% of the individuals for whom isoniazid chemoprophylaxis was recommended completed the 6 months of therapy. Most clinical employees (96.1%) did not have a history of prior hepatitis B virus (HBV) infection or immunization, but 77% of them subsequently completed the vaccination series. Most employees with a negative history for infection with or immunization against rubella, rubeola, and varicella had serological evidence of immunity (90.2%, 97.9%, and 87.2%, respectively). CONCLUSIONS: Review of aggregate employee health databases may assist individuals who must establish strategies for prevention of occupational illness and disease transmission in this specialized setting. While many employees at risk for HBV complete the vaccination series, strategies for improving this rate could be helpful. Substantial work is needed to analyze reasons why so few individuals for whom isoniazid chemoprophylaxis is recommended complete the therapy, and strategies tailored to the impediments identified should be implemented.

Adolescent↗
PubMed1998

An NCEP II diet reduces postprandial triacylglycerol in normocholesterolemic adults.

We compared the fasting and postprandial response to a National Cholesterol Education Program (NCEP) II diet with that of a diet high in total (40% of energy) and saturated fat. In free-living conditions, 17 healthy normolipidemic, normoglycemic men and women consumed a high-fat diet, a maintenance diet and the NCEP II diet, for 1 mo each. At the completion of each dietary period, an oral fat load (70 g/m2 body surface area) was administered and plasma triacylglycerol (TAG) determined every 2 h for 8 h. Compared with the high-fat phase, the NCEP II diet was associated with significantly lower energy intake (12.1 +/- 1.1 vs. 7 +/- 0.7 MJ/d) and final body weight (78 +/- 3.8 vs. 76.3 +/- 3.5 kg) (P < 0.01). Plasma high density lipoprotein cholesterol, apolipoprotein (apo) A-I and ApoB concentrations were also significantly lower when subjects consumed the NCEP II diet rather than the high-fat diet (P </= 0.004). There were no significant differences in subjects fasting TAG, glucose or insulin concentration between the high fat and NCEP II diet periods. However, the postprandial plasma TAG response to the fat load was lower after completing the NCEP II than after the high-fat diet period (P = 0.045). Under free-living conditions, a NCEP II diet was associated with weight loss and a decrease in postprandial but not fasting TAG. Because dietary alteration may not affect fasting TAG levels, thorough assessment of a dietary intervention should include measurements of postprandial TAG.

Adult↗
PubMed1998

Inter-clinician agreement on clinical data abstracted from patients' medical charts.

PURPOSE: The purpose of this study was to determine the inter-observer repeatability of retrospective chart reviews. METHODS: Retrospective abstraction of corneal transplant patients' medical records by two independent observers was performed at the University of California, Davis, Department of Ophthalmology, Sacramento, CA. The sample consisted of 100 consecutive patients who underwent penetrating keratoplasty, and the primary outcome measure was the degree of agreement between the 2 independent observers on clinical ocular data abstracted from patients' medical charts. RESULTS: Even when given specific criteria for abstraction of data from patients' medical charts, inexperienced but trained observers exhibited a small degree of disagreement (range 0 to 12%) on patient demographic variables (e.g., gender, age, and date of birth) to be used for data analysis. Larger amounts of disagreement (range 3 to 26%) were found on frequently occurring variables (e.g., predisposing ocular conditions, surgical complications, and classification of corneal staining). CONCLUSIONS: Based on these data, inter-observer repeatability for retrospective chart review studies is good, but investigators using this study methodology must be quite specific about the data to be collected and should be aware of standardization techniques to enhance observer repeatability.

Abstracting and Indexing↗
PubMed1998

Arginine vasopressin levels in nursing home residents with nighttime urinary incontinence.

OBJECTIVES: To examine the relationship between diurnal urine volume and plasma arginine vasopressin levels (AVP) in nursing home residents with nighttime urinary incontinence and a comparison group of frail but nondemented, continent geriatric board and care residents. DESIGN: Case series. SETTING: Four nursing homes and two board and care facilities. PARTICIPANTS: Sixty-two nursing home residents and 27 board and care residents. MEASUREMENTS: Daytime (7:00 a.m. to 7:00 p.m.) and nighttime (7:00 p.m. to 7:00 a.m.) urine volumes of incontinent nursing home residents were measured over 3 days and 3 nights by reweighing preweighed adults diapers and toileting inserts emptied by research staff for the comparison group. AVP levels were drawn in the early morning (5:00 a.m. to 7:00 a.m.) before subjects arose and in the evening after an hour of lying in bed (8:00 p.m. to 11:00 p.m.), and plasma levels were determined by radioimmunoassay. RESULTS: Half of the nursing home residents and 82% of the comparison group had night/total urine volume ratios > or = 50%. Forty-nine percent of the total of 89 subjects had undetectable morning AVP levels, 61% had undetectable evening AVP levels, and 42% had undetectable AVP levels in both morning and evening. There were no significant differences in AVP levels between those with night/total urine volume ratios > or = 50% and < 50% in either the nursing home or comparison groups though the small number of comparison group subjects with ratios < 50% may have limited our statistical power to detect differences. CONCLUSION: Our data suggest that a substantial proportion of both nursing home residents with nighttime incontinence and frail geriatric patients with a reversal of the normal diurnal pattern of urine excretion have an accompanying deficiency in AVP production and/or secretion. More detailed physiologic studies are needed to understand better the pathophysiology of geriatric nocturia and nighttime incontinence and the role that AVP deficiency may play in these conditions. Until such studies are carried out, we do not recommend the routine use of exogenous AVP for geriatric patients with unexplained nocturnal polyuria.

Aged↗
PubMed1998

The use of fluorogenic substrates to measure fungal presence and activity in soil.

Our objective was to determine if 4-methylumbelliferyl-labelled enzyme substrates could be used to detect and quantify specific components of chitinase and cellulase activities as specific indicators of the presence and activity of fungal biomass. The fluorogenic substrates 4-methylumbelliferyl (MUF) N-acetyl-beta-D-glucosaminide and MUF beta-D-lactoside were used for the detection and quantification of beta-N-acetylglucosaminidase (EC 3.2.1.30) (NAGase) and endo 1,4-beta-glucanase (EC 3.2.1.4)/cellobiohydrolase (EC 3.2.1.91) (CELase), respectively. Culture screenings on solid media showed a widespread ability to produce NAGase among a taxonomically diverse selection of fungi on media with and without added chitin. NAGase activity was expressed only in a limited number of bacteria and on media supplemented with chitin. The CELase activity was observed only in a limited number of fungi and bacteria. Bacterial CELase activity was expressed on agar media containing a cellulose-derived substrate. In soil samples, NAGase activity was significantly correlated with estimates of fungal biomass, based on the content of two fungus-specific indicator molecules, 18:2 omega 6 phospholipid fatty acid (PLFA) and ergosterol. CELase activity was significantly correlated with the PLFA-based estimate of fungal biomass in the soil, but no correlation was found with ergosterol-based estimates of fungal biomass.

Acetylglucosaminidase↗
PubMed1998

Actinobacillus actinomycetemcomitans leukotoxin induces apoptosis in HL-60 cells.

Actinobacillus actinomycetemcomitans leukotoxin (Ltx) is a member of the repeats-in-toxin (RTX) family of pore-forming toxins and kills human immune cells. Currently, it remains unclear whether toxin-mediated killing of target cells involves the induction of necrosis or apoptosis. Therefore, the goal of this investigation was to determine whether Ltx is capable of causing apoptotic cell death in toxin-sensitive promyelocytic HL-60 cells. Multiparameter flow cytometric analysis of toxin-treated cells stained with Hoechst 33258 (or 33342) and 7-aminoactinomycin D allowed us to identify four populations: viable cells, early apoptotic cells, late apoptotic and/or secondarily necrotic cells, and a final population that was composed of cellular debris. Compared with control cells, HL-60 cells treated with Ltx exhibited a gradual decrease in forward light scatter with a coincident increase in side light scatter, indicative of a decrease in cell size and organelle condensation, respectively. Additional experiments demonstrated that Ltx-treated cells showed evidence of internucleosomal DNA fragmentation and phosphatidylserine translocation. The results of our studies clearly demonstrate that Ltx can kill HL-60 cells by inducing apoptosis. We hypothesize that elimination of acute inflammatory cells via this mechanism plays a critical role in the pathogenesis of diseases caused by A. actinomycetemeomitans.

Aggregatibacter actinomycetemcomitans↗
PubMed1998

Apolipoprotein A-I(Zavalla) (Leu159-->Pro): HDL cholesterol deficiency in a kindred associated with premature coronary artery disease.

We investigated the molecular defect causing high density lipoprotein cholesterol (HDL-C) deficiency in a male proband and his family members. Amplification and sequencing of genomic DNA disclosed a novel base-pair substitution at residue 159 in the apolipoprotein (apo) A-I gene. This substitution resulted in the loss of an AviII restriction site and a predicted substitution of leucine with proline at residue 159. Restriction enzyme analysis demonstrated absence of the AviII site in 19 of 40 biological family members. Compared with familial controls, subjects with the apoA-I(Zavalla) variant had reduced HDL-C (1.16 versus 0.27 mmol/L, P<0.0001), apoA-I (38.7 versus 124.4 mg/dL, P<0.0001), and apoA-II (14.3 versus 19.0 mg/dL, P<0.0001) levels. Two subjects who have developed coronary artery disease to date possess additional cardiovascular risk factors. Other heterozygotes for apoA-I(Zavalla) are presently without symptomatic coronary artery disease. This study identifies a monogenic cause of hypoalphalipoproteinemia, with the single base-pair substitution having a dominant effect on the low HDL-C phenotype. In addition, it extends recent observations that HDL-C deficiency states may be more prone to the development of premature coronary artery disease when accompanied by additional cardiovascular risk factors.

Adolescent↗
PubMed1998

Economic analysis of fluconazole versus amphotericin B for the treatment of candidemia in non-neutropenic patients.

Fluconazole (FLU) is an alternative to amphotericin B (AMB) for the treatment of candidemia in non-neutropenic patients. This agent has similar clinical efficacy but significantly reduced adverse effects compared with AMB. Using the database from a Canadian randomised multicentre comparative trial of FLU versus AMB in the treatment of non-neutropenic patients with candidemia, an economic analysis of antifungal therapy was conducted from a Canadian hospital perspective. Patient records were examined for information containing hospital resource consumption. This included the costs for primary intravenous therapy with either AMB or FLU, laboratory tests, patient clinical monitoring and adverse effects management. The robustness of the baseline results were then tested by a comprehensive sensitivity analysis. The mean duration of therapy in the AMB and FLU arms was 17.1 and 23.7 days, respectively (p < 0.001). Assuming that all of the FLU was administered intravenously, the outcomes of the baseline economic analysis revealed that the treatment cost for patients randomized to receive FLU was approximately 50% higher than that for patients treated with AMB [AMB: $Can2370 vs FLU: $Can3578; p = 0.001 ($Can = Canadian dollars)]. In the sensitivity analysis, substitution to oral FLU after 7 days of intravenous therapy produced economic differences that were no longer statistically significant (AMB: $Can2370 vs FLU: $Can2705; p = 0.10). These results suggest that the FLU administration regimen used in the Canadian randomized trial for the treatment of candidemia in non-neutropenic patients may result in increased hospital costs compared with AMB. However, comparable expenditures could be realized if FLU is administered intravenously for the first 7 days and then orally in patients whose condition allows for reliable oral therapy.

Adult↗
PubMed1998

Evaluation of an approach for adults with profound learning difficulties.

A local day care unit for adults with profound learning disabilities is a popular community project. It receives many visits from students and volunteers and is also visited by a variety of support staff. The presence of these visitors makes an impact on the Unit's communication environment. A nursing and speech and language therapy project used photography to address the visitors' perceptions of the clients' communication and identify the visitors' information needs about the clients' communication skills. As a result of this evaluation the induction policy was changed and the leaflets were introduced. The time commitment to the initial project for therapy and nursing staff is discussed in relation to the effective and alternative use of therapeutic time for this client group.

Adult↗
PubMed1998

Learning with technology: use of case-based physical and computer simulations in professional education.

This presentation will clarify contemporary ideas on the role of technology in education and how it can be employed to improve student learning experiences and outcomes. The paper will emphasise RMIT's role in providing quality education that is relevant to today's world and professional practice. It will examine a specific collaborative (RMIT & ACU), interdisciplinary project 'Pregnancy Simulator: Developing and Enhancing Student Learning of Assessment Skills'. This project consist of a physical pregnancy model connected to a multi-media computer-assisted learning package for the purpose of enhancing student learning of abdominal assessment skills. Our paper outlines an innovative technology-based teaching project and includes current educational issues or problems encountered in professional education, steps already taken to address these difficulties and how this project intends to facilitate learning. It identifies expected learning outcomes for midwives, nurses and medical students, and examines pedagogical principles applied to technological applications designed to provide guided discovery for allowing students to build confidence and competence in professional education. The case-based physical and computer simulations contextualise learning to assist transfer of learning to real world situations. This paper will also discuss how technology-based projects can be evaluated and integrated into university curricula to enhance student learning.

Computer Simulation↗
PubMed1998

Learning with technology: use of case-based physical and computer simulations in professional education.

This paper describes a multimedia technology project in midwifery education and how it is being developed to improve student learning experiences and outcomes. The role of the university providing quality education relevant to today's world and professional practice is emphasised. A collaborative (Royal Melbourne Institute of Technology and Australian Catholic University) interdisciplinary project 'Pregnancy Simulator: Developing and Enhancing Student Learning of Pregnancy Assessment Skills' was developed with university and direct Commonwealth support. This project consists of a physical simulation of a pregnant woman at term and case-based multimedia computer simulations designed to develop and enhance student learning of abdominal assessment skills. A key feature of the development has been to design a learning experience explicitly on an authoritative theory-based view of teaching, in this case Diana Laurillard's 'Conversational Framework'.

Computer Simulation↗