PubMed Health⌕ Search

Biomedical subjects

R L Schmitt

Publications and source records attributed to R L Schmitt.

14 recordsLinked to original sources
PubMed2004

First results from the Cryogenic Dark Matter Search in the Soudan Underground Laboratory.

We report the first results from a search for weakly interacting massive particles (WIMPs) in the Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory. Four Ge and two Si detectors were operated for 52.6 live days, providing 19.4 kg d of Ge net exposure after cuts for recoil energies between 10 and 100 keV. A blind analysis was performed using only calibration data to define the energy threshold and selection criteria for nuclear-recoil candidates. Using the standard dark-matter halo and nuclear-physics WIMP model, these data set the world's lowest exclusion limits on the coherent WIMP-nucleon scalar cross section for all WIMP masses above 15 GeV/c2, ruling out a significant range of neutralino supersymmetric models. The minimum of this limit curve at the 90% C.L. is 4 x 10(-43) cm2 at a WIMP mass of 60 GeV/c2.

Journal Article↗
PubMed2000

Immune function in female elite rowers and non-athletes.

OBJECTIVE: To compare immune function in female rowers and controls in the resting state, and then correlate the results with a two month history of upper respiratory tract infection (URTI). METHODS: Subjects included 20 elite female rowers located at the ARCO Olympic Training Centre in Chula Vista, California, and 19 non-athletic female controls. These two groups were compared cross sectionally for immune function and infection rates. RESULTS: Granulocyte/monocyte phagocytosis, oxidative burst activity, and plasma cytokine concentrations (interleukin-6, tumour necrosis factor-alpha, and interleukin-1 receptor antagonist) did not differ significantly between groups. Phytohaemagglutinin induced lymphocyte proliferative response (adjusted whole blood method) was significantly higher (31% and 36% for optimal and suboptimal concentrations respectively) in rowers than in controls. Natural killer cell activity was substantially higher (1.6-fold for total lytic units) in the female rowers than in controls. Two month health logs disclosed 5.2 (1.2) and 3.3 (1.1) days with URTI symptoms for the rowers and controls respectively (p = 0.268). For all 39 subjects combined, and for the 20 rowers separately, none of the immune parameters correlated significantly with number of days with URTI symptoms. CONCLUSIONS: In this cross sectional comparison of elite female rowers and non-athletes, a group difference was found for natural killer cell activity and phytohaemagglutinin induced proliferative response (whole blood technique), but not other measures of immune function. The number of days with URTI symptoms during the spring season did not differ between groups, and variations in blood measures of immunity were unrelated to URTI.

Adolescent↗
PubMed1997

Carbohydrate and the cytokine response to 2.5 h of running.

This randomized, double-blind, placebo-controlled study was designed to determine the influence of 6% carbohydrate (C) vs. placebo (P) beverage ingestion on cytokine responses (5 total samples over 9 h) to 2.5 h of high-intensity running (76.7 +/- 0.4% maximal O2 uptake) by 30 experienced marathon runners. For interleukin-6 (IL-6), a difference in the pattern of change between groups was found, highlighted by a greater increase in P vs. C immediately postrun (753 vs. 421%) and 1.5 h postrun (193 vs. 86%) [F(4,112) = 3.77, P = 0.006]. For interleukin-1-receptor antagonist (IL-1ra), a difference in the pattern of change between groups was found, highlighted by a greater increase in P vs. C 1.5 h postrun (231 vs. 72%) [F(2,50) = 6.38, P = 0.003]. No significant interaction effects were seen for bioactive IL-6 or IL-1 beta. The immediate postrun plasma glucose concentrations correlated negatively with those of plasma cortisol (r = -0.67, P < 0.001); postrun plasma cortisol (r = 0.70, P < 0.001) and IL-6 levels (r = 0.54, P = 0.003) correlated positively with levels of IL-1ra. Taken together, the data indicate that carbohydrate ingestion attenuates cytokine levels in the inflammatory cascade in response to heavy exertion.

Adult↗
PubMed1988

Dieldrin-induced changes in isoenzyme composition in the livers of CF-1 mice.

The isoenzyme composition of lactic dehydrogenase (LDH), pyruvate kinase (PK) and alanine-aminotransferase was determined in the livers of CF-1 mice exposed to 0, 5 or 10 ppm dieldrin in the diet, over a period of 14 months. This study was carried out to evaluate whether the liver tumor promoter dieldrin advances the biological age of CF-1 mouse liver. Oral dieldrin exposure induced a dose-dependent shift towards the fetal types of lactic dehydrogenase and pyruvate kinase, within 1.5 months of initiation of treatment. After the initial shift, no additional dieldrin-dependent changes were found in CF-1 mouse liver throughout the experimental observation period. Thus, the initial shifts in isoenzyme composition of LDH and PK appear to reflect the adaptation of the liver to increased functional demands imposed by dieldrin treatment. The expression of the cytoplasmic A-alanine-aminotransferase isoenzyme decreased with age in untreated control mice. Dieldrin treatment enhanced this process in a dose-dependent manner. These data suggest that dieldrin treatment can accelerate age-dependent changes in gene expression.

Aging↗
PubMed1986

Evaluation of the efficacy of piracetam in treating information processing, reading and writing disorders in dyslexic children.

Piracetam, a new class of drug (nootropil) thought to enhance specific cognitive skills, was given in a 3300 mg daily dose to half of a group of fifty-five dyslexic boys aged 8-13 years, in a 12-week, double-blind, placebo-controlled study. The other half of the subjects received placebo. All subjects met the following criteria: normal intelligence, normal educational opportunities, no severe emotional problems, no neurological handicaps, good physical health, not taking other psychotropic medication, and scoring at least one and one half years below their mental age equivalent on the Gilmore Oral Reading Test. Non-verbal (auditory and visual) and verbal perceptual, and memory skills were examined, and reading, spelling, language and writing abilities were measured using standardized instruments. Compared to the placebo control group, individuals treated with Piracetam did not show statistically significant improvements above their baseline scores on measures of perception, memory, language, reading accuracy or comprehension, or writing accuracy. However, reading speed and numbers of words written in a timed period were significantly enhanced in subjects treated with Piracetam as compared to placebo. Effective reading and writing ability, taking both rate and accuracy into consideration, were also significantly improved in the Piracetam as compared to the placebo treatment group. The medication was well-tolerated and medical examinations showed no significant adverse reactions. These results encourage further study of Piracetam to determine more precisely the mechanism of action by which specific cognitive skills are affected.

Adolescent↗
PubMed1983

Increased plasma ammonia may inhibit cellular release of branched-chain amino acids in systemic portal encephalopathy.

Plasma amino acid patterns were determined before and after hemofiltration (HF) and hemodialysis (HD) in 6 patients with portal systemic encephalopathy (PSE) and compared with the plasma AA patterns of 16 patients with chronic renal failure (CRF) treated either by HF or HD. The branched-chain amino acids (BCAA) increased paradoxically in PSE patients during HF but not with HD. There were no differences in BCAA's with HF as compared to HD in the CRF patients. The amount of amino acids lost was the same with both treatment modalities and in both patient groups. Much of the amino acids lost were released from the intracellular space. The BCAA release was significantly higher in PSE patients during HF. No correlation was found between plasma insulin, glucagon, and cortisol levels and BCAA release. An inverse correlation was found between the amount of BCAA's released from the intracellular space and the plasma ammonia levels. It is suggested that a selective cellular transport mechanism for BCAA exists which is inhibited by high plasma ammonia levels in PSE.

Adult↗
PubMed1981

Adult marijuana use and Becker's social controls.

Adults who smoke marijuana regularly but who are conventional in other respects are the subjects of study. The objective was to determine how a sample of adults handle the three social controls facing marijuana smokers depicted by Becker. A content analysis of the results of a self-administered questionnaire show that while some subjects are more concerned than others about these controls, they all use coping devices to deal with them.

Adult↗
PubMed1980

The assessment of stigma: implications for theory and intervention.

Self-disclosure data from marijuana smokers are considered. Attention is given to disclosure patterns in relation to four types of reference individuals and to feelings about disclosure. Users were most likely to disclose and to feel comfortable about disclosing to high intimate and nonauthority reference individuals. They were less likely to disclose and to feel comfortable about disclosing (1) to low intimate and nonauthority reference individuals, and (2) to authority-reference individuals--irrespective of their intimacy with them. The implications of a self-disclosure-reference-individual strategy for the study of stigma and for intervention purposes are discussed.

Adult↗