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Biomedical subjects

L A Fletcher

Publications and source records attributed to L A Fletcher.

10 recordsLinked to original sources
PubMed2005

Acute exposure to cyclosporine does not increase plasma homocysteine in rats.

There is interest in the postulate that cyclosporine a (CsA) contributes to the elevated homocysteine levels seen in organ transplant recipients, as hyperhomocysteinemia is now considered an independent risk factor for cardiovascular disease (CVD) and may partially explain the increased prevalence of CVD in this population. The main purpose of this investigation was to determine the effect of CsA administration on plasma homocysteine. Eighteen female Sprague Dawley rats (4 months old) were randomly assigned to either a treatment or a control group. For 18 days the treatment group received of CsA (25 mg/kg/d) while the control group received the same volume of the vehicle. Blood samples obtained following sacrifice to measure CsA, total homocysteine, and plasma creatinine. There were no significant differences in plasma homocysteine (mean values +/- SD: treatment = 4.79 +/- 0.63 micromol/L, control = 4.46 +/- 0.75 micromol/L; P = .37). Homocysteine was not significantly correlated with final CsA concentrations (r = .17; P = .69). There was a significant difference in plasma creatinine values between the two groups (treatment = 60.44 +/- 7.68 micromol/L, control = 46.33 +/- 1.66 micromol/L; P < .001). Furthermore, plasma homocysteine and creatinine were positively correlated with the treatment group (r = .73; P < .05) but not the controls (r = -.10; P = .81). In conclusion, CsA does not influence plasma homocysteine concentrations in rats.

Animals↗
PubMed2003

The transmission of tuberculosis in confined spaces: an analytical review of alternative epidemiological models.

Tuberculosis (TB) is a disease that is closely associated with poverty, with transmission occurring in situations where infected persons are in close contact with others in confined spaces. While it is well recognised that overcrowding increases the risk of transmission, this increased risk has not been quantified and the relationship between overcrowding and duration of exposure is not well understood. This paper analyses three epidemiological models that have been used to predict the transmission of airborne disease in confined spaces: the Mass Action model, Riley, Murphy and Riley's model and Gammaitoni and Nucci's model. A study is presented to demonstrate the range of applicability of each model and show how they can be applied to the transmission of both TB and diseases with short incubation periods such as measles. Gammiatoni and Nucci's generalised formulation is shown to be the most suitable for modelling airborne transmission in ventilated spaces, and it is subsequently used in a parametric study to evaluate the effect of physical and environmental factors on the rate of disease transmission. The paper also presents reported quanta production data for several TB outbreaks and demonstrates that the greatest risk of TB infection is during clinical procedures that produce large quantities of aerosol, such as bronchoscopy or intubation.

Disease Transmission, Infectious↗
PubMed2000

Alcohol home delivery services: a source of alcohol for underage drinkers.

OBJECTIVE: This study describes the use of alcohol home delivery services by underage drinkers, and characteristics of grocery and liquor stores that deliver alcohol. The availability of alcohol home delivery services across the United States is also described. METHOD: Individuals surveyed were from 15 small- and medium-sized midwestern communities. Of all enrolled 12th graders, 83.5% (N = 4,487) responded, and of a randomly selected cohort of 18- to 20-year-olds, 93.9% (N = 1,721) responded. All grocery stores that sold alcohol and liquor stores in the corresponding communities were invited to participate in the study and 124 (92.5%) of those businesses completed surveys regarding outlet characteristics and practices. Data for the surveys were based on a nested cross-sectional design with individual respondents nested within the 15 communities. RESULTS: Purchases of delivered alcohol were made by 10% of 12th graders and 7.3% of 18- to 20-year-olds within the past year; 20.2% of outlets delivered alcohol. Using bivariate analyses, purchasing delivered alcohol was associated with male gender, high-risk drinking (drinking five or more drinks on an occasion), more recent and more frequent drinking. Providing delivery services was more common among outlets selling keg beer and/or single servings. Multivariate analyses revealed positive associations between purchasing delivered alcohol and male gender for the 12th graders, and high risk and more recent drinking for both the 12th graders and 18- to 20-year-olds. For outlets, selling keg beer was positively associated with providing delivery services. A separate survey indicated that home delivery services appear to be available in many areas of the country. CONCLUSIONS: Home delivery is a previously unidentified source of alcohol for underage drinkers that could be curtailed with effective alcohol policies.

Adolescent↗
PubMed1998

Exercise training reduces myocardial lipid peroxidation following short-term ischemia-reperfusion.

PURPOSE: The purpose of these experiments was to test the hypothesis that endurance exercise training will reduce myocardial lipid peroxidation following short-term ischemia and reperfusion (I-R). METHODS: Female Sprague-Dawley rats (4 months old) were randomly assigned to either a sedentary control group (N = 13) or to an exercise training group (N = 13). The exercise trained animals ran 4 d.wk-1 (90 min.d-1) at approximately 75% V02max. Following a 10-wk training program, animals were anesthetized, mechanically ventilated, and the chest was opened by thoracotomy. Coronary occlusion was achieved by a ligature around the left coronary artery; occlusion was maintained for 5 min followed by a 10-min period of reperfusion. RESULTS: Although training did not alter (P > 0.05) myocardial activities of antioxidant enzymes (superoxide dismutase and glutathione peroxidase), training was associated with significant increase (P > 0.05) in heat shock protein (HSP72) in the left ventricle. Compared with controls, trained animals exhibited significantly lower levels (P < 0.05) of myocardial lipid peroxidation following I-R. CONCLUSION: These data support the hypothesis that exercise training provides protection against myocardial lipid peroxidation induced by short-term I-R in vivo.

Animals↗
PubMed1997

A clinical tool for rating response to civil commitment for substance abuse treatment.

OBJECTIVE: The objectives of this study were to develop a measure to assess patients' response to civil commitment, to test this measure on two groups of dually diagnosed patients (medically ill alcoholics and patients with dual mental and substance use disorders), and to identify patient characteristics associated with a positive response to commitment. METHODS: The outcome of 38 male veterans civilly committed to inpatient substance abuse treatment for an average of six months was rated by their treating clinicians. Raters used the Commitment Response Form (CRF), a scale anchored to behavioral descriptions that was developed for the study and that measures outcome in five areas: patients' attitude toward recovery, substance use, medical condition, engagement in substance abuse treatment, and independence of functioning. Each patient's medical records were reviewed by two clinical staff members who made independent retrospective ratings and a joint rating using the CRF. They also made independent and joint dichotomous ratings of whether the patient was a positive responder or a nonresponder to civil commitment. RESULTS: The CRF showed superior reliability when compared with the dichotomous rating of outcome. The scale demonstrated reasonable psychometric properties. Mean scale scores did not differ significantly by patient group; slightly more than half were rated as having a good to excellent overall response. Better outcome was associated with longer periods of previous abstinence from alcohol and a higher level of education. CONCLUSIONS: Use of a scale anchored to behavioral descriptions improved reliability of outcome determinations by clinical staff. Civil commitment resulted in good to excellent outcome in many but not all committed patients.

Adult↗
PubMed1996

The use of alcohol home delivery services by male problem drinkers: a preliminary report.

Alcohol home delivery services (AHDS) provide convenient and confidential access to alcohol, yet little is known about their use. The purpose of this report is to present preliminary data describing the use of AHDS by problem drinkers. We surveyed 174 males regarding social and demographic characteristics, alcohol use history, and use of AHDS. Use of AHDS was most common among problem drinkers. When statistically controlling for the effects of demographic and social characteristics, regular drinkers without a history of alcohol problems were significantly less likely to have had alcohol delivered than problem drinkers, p = .0036. Contrary to expectation, medically ill alcoholics with advanced and disabling medical complications of heavy drinking were not more likely than other problem drinkers to have alcohol delivered. Living in an urban area and not having a vehicle available were associated with the use of AHDS. The public health and safety considerations of alcohol availability via home delivery are discussed.

Adult↗
PubMed1982

Minimal velocities necessary for perforation of skin by air gun pellets and bullets.

A series of tests were conducted to determine the velocities necessary for lead air gun pellets (calibers .177 and .22) and caliber .38 lead bullets to perforate skin. Human lower extremities were used. Caliber .177 air gun pellets weighing 8.25 grains required a minimum velocity of 101 m/s (331 ft/s) to perforate skin. The energy per area of presentation ratio E/a was 1:86 m X kg/cm2. Caliber .22 air gun pellets weighing 16.5 grains needed a minimum velocity of 75 m/s (245 ft/s). The E/a was 1:3 m X kg/cm2. A round nose, caliber .38 lead bullet weighing 113 grains perforated skin at 58 m/s (191 ft/s). The E/a was 1.95 m X kg/cm2. These studies appear to indicate that lightweight projectiles need greater velocity to perforate skin than do larger caliber, heavier bullets.

Forensic Medicine↗