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V Porter

Publications and source records attributed to V Porter.

11 recordsLinked to original sources
PubMed1998

Recruitment strategies in the women's health trial: feasibility study in minority populations. WHT:FSMP Investigators Group. Women's Health Trial:Feasibility Study in Minority Populations.

The Women's Health Trial:Feasibility Study in Minority Populations (WHT:FSMP) examined the feasibility of recruiting postmenopausal women from a broad range of racial and socioeconomic backgrounds into a primary prevention trial requiring marked reductions in dietary fat. Postmenopausal women aged 50-79 yr who had no history of cardiovascular disease or cancer and who consumed 36% or more total energy from fat qualified to participate. We randomized the women into dietary intervention (60%) or control (40%) groups; we aimed to randomize 750 women in 18 months in each of the three clinical centers. All centers achieved goals for randomization based on ethnicity, and two centers exceeded overall recruitment goals. The greatest source of randomized participants was mass mailing, followed by items in the media, referrals, and community outreach. Recruitment yields were generally similar for the ethnic groups but lower for less-educated participants. The experience of WHT:FSMP indicates that postmenopausal women from the African-American, Hispanic, and non-Hispanic white communities can be recruited into dietary intervention studies for the prevention of disease.

Black or African American↗
PubMed1996

gamma-Aminobutyric acidA receptors and spinally mediated antinociception in rats.

Experiments were performed on rats with lumbar subarachnoid catheters, using four agonist drugs [gamma-aminobutyric acid (GABA), muscimol, midazolam and 5-hydroxytryptamine (5-HT)] and two GABA(A) antagonists (bicuculline and SR-95531) given intrathecally. All four agonists caused dose-related antinociception assessed by the electrical current threshold test. These effects were spinally mediated because the agonists caused increases in nociceptive thresholds in the skin of the tail and not the neck. In the same experiments, 5-HT and GABA caused simultaneous increases in tail-flick latency and electrical current thresholds in the tail. Both GABA(A) antagonists caused dose-related suppression of the antinociceptive effects of equieffective doses of all four agonists. Tail-flick latency increases caused by 5-HT were not suppressed by bicuculline in the same experiments in which bicuculline had suppressed the electrical current threshold effects of intrathecal 5-HT. The log dose-response curves for both antagonists for suppression of GABA effects were coincident, having a very shallow slope and covering the whole range of doses effective against the other agonists. The two GABA(A) antagonists were very different in relative potency for suppression of the spinally mediated antinociceptive effects of the other three agonists. The rank order of potency for bicuculline suppression of the effects of equieffective doses of the other agonists was muscimol > 5-HT > midazolam, whereas the rank order for SR-95531 was muscimol >> midazolam > 5-HT. We conclude that there exist in the spinal cord at least three different GABA(A) receptors responsible for spinally mediated antinociception caused by intrathecal injections of midazolam, muscimol and 5-HT. These are all targets for endogenous GABA.

Animals↗
PubMed1990

Left ventricular hypertrophy reversal with labetalol and propranolol: a prospective randomized, double-blind study.

Hypertensive patients with left ventricular hypertrophy (LVH) have increased cardiovascular morbidity and mortality. Experimental studies indicate the importance of both the alpha and beta components of the adrenergic nervous system in the development and reversal of LVH. Therefore labetalol (L), a combined alpha and beta blocker, and propranolol (P), a nonselective beta blocker, were evaluated in a randomized, double-blind study of 35 hypertensive patients with echocardiographic evidence of LVH. Following 2 weeks of placebo, L or P was titrated as needed and tolerated to maximum total daily doses of 1600 mg and 640 mg, respectively. A thiazide diuretic was added if necessary for blood pressure control. M-mode echocardiograms were performed at baseline and after 1, 3, 6, and 12 months of blood pressure control. The echocardiograms were read independently by two blinded observers for end-diastolic dimension and wall thicknesses, and left ventricular mass. Fractional shortening, cardiac output, and peripheral vascular resistance were derived using standard formulas. Both drugs reduced blood pressure significantly and comparably. Significant changes in the echocardiographic measurements were observed as early as 1 month and usually persisted throughout the study. Both drugs decreased posterior wall thickness; however, only the decrease in propranolol group achieved statistical significance. Septal wall thickness was reduced by L at 3 and 12 months. End-diastolic dimension increased significantly in the L-treated group at 3, 6, and 12 months of therapy, whereas P had no effect on this measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Aerobic capacity of Polish soldiers.

Performances on 1.5-mile and 12-minute runs were used to compare aerobic fitness in groups of Polish, Austrian, and U.S. male military members. The Polish soldiers achieved better times than either the Americans or the Austrians, and both Polish and Austrians logged better times than the Americans, a possible indication of better fitness. Non-smokers performed better than smokers. Since coronary heart disease (CHD) is the leading non-accidental cause of death in the U.S. Armed Forces, higher levels of physical fitness may decrease the incidence of CHD in the U.S. military. A healthy lifestyle and motivation seem to have positive effects on physical fitness.

Adult↗
PubMed1975

Fermentation reactions of Actinobacillus and Pasteurella in commercial media.

The applicability, reliability and accuracy of various carbohydrate media in the determination of fermentation reactions of 16 Pasteurella and Actinobacillus isolates were investigated. Laboratory prepared and commercially prepared carbohydrate media were inoculated with known test organisms and results were compared with those obtained at the Center for Disease Control (CDC). Only two of the 15 media tested reproduced more than 90 per cent of the reactions obtained at CDC. Significant differences in performance were noted depending on source and type of dehydrated media, manufacturer, type of carbohydrate and isolate studied. Considerations for media selection are summarized.

Actinobacillus↗
PubMedDate not supplied

Decline in CD28+ T cells in centenarians and in long-term T cell cultures: a possible cause for both in vivo and in vitro immunosenescence.

The dramatic decline in immune function with age, especially in T cell proliferative activity, has been documented extensively in experimental animal models and in clinical studies of the elderly. A similar proliferative decline is also seen in long-term T lymphocyte cultures used to study in vitro cellular senescence. We have compared the peripheral blood T lymphocytes of centenarians and younger controls for the cell surface expression of CD28, a costimulatory molecule that is required for optimal activation and proliferation following engagement of the T cell receptor. Our analysis shows a significant decrease (p < 0.001) in the percentage of T cells expressing CD28 in the elderly cohort, with values ranging from 44% to 90%, as compared to the mean control value of 91%. The decline in the percentage of CD28+ T cells correlates with a reduction in the CD4/CD8 ratio (r2 = 0.695, p < 0.0001). Concommitantly, experiments using an in vitro T cell culture system showed a progressive loss of CD28 expression with culture "age." The concordance of proliferative decline and loss of CD28 in the centenarians and in the in vitro cultures suggest that a Hayflick phenomenon may operate in vivo leading to immunosenescence.

Adult↗