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Biomedical subjects

A Rider

Publications and source records attributed to A Rider.

8 recordsLinked to original sources
PubMed2005

Genetic determinants on rat chromosome 6 modulate variation in the hypercapnic ventilatory response using consomic strains.

To understand the genetic basis of pathways involved in the control of breathing, a large scale, high-throughput study using chromosomal substitution strains of rats is underway. Eight new consomic rat stains (SS-2(BN), SS-4(BN), SS-6(BN), SS-7(BN), SS-8(BN), SS-11(BN), SS-12(BN), SS-14(BN), SS-Y(BN)), containing one homozygous BN/NHsdMcwi (BN) chromosome on a background of SS/JrHsdMcwi (SS), were created by PhysGen (http://pga.mcw.edu) Program for Genomic Applications. Male and female rats were studied using standard plethysmography under control conditions and during acute hypoxia (inspired oxygen fraction = 0.12) and hypercapnia (inspired CO(2) fraction = 0.07). The rats were also studied during treadmill exercise. Both male and female BN rats had a significantly lower ventilatory response during 7% CO(2) compared with SS rats of the same gender. SS-6(BN) female rats had a significantly reduced ventilatory response, similar to BN rats due primarily to a reduced tidal volume. Male SS-6(BN) rats had a significantly reduced tidal volume response to hypercapnia but a slightly increased frequency response during hypercapnia. Gene(s) on the Y chromosome may play a role in this increased frequency response in the male rats because the SS-Y(BN) hypercapnic ventilatory response involves a significantly increased frequency response. Several chromosomal substitutions slightly altered the ventilatory responses to hypoxia and exercise. However, genes on chromosomes 6 and Y of those studied are of primary importance in aspects of ventilatory control currently studied.

Animals↗
PubMed1989

Relationship between carotenoids and cancer. The Multiple Risk Factor Intervention Trial (MRFIT) Study.

We evaluated the baseline serum levels of beta carotene, total carotenoids, vitamin A and E, and retinol-binding protein among 156 initially healthy men who participated in the Multiple Risk Factor Intervention Trial (MRFIT) and who subsequently died of cancer and 311 controls individually matched for age, smoking status, randomization group, date of randomization, and clinical center. Both total carotenoids and beta carotene levels were lower in the 66 lung cancer cases than in their matched controls. For all cancer deaths combined, there were no significant differences in total carotenoids or beta carotene between cases and controls. The relationship between lower serum carotenoid levels and lung cancer persisted after adjusting for the number of cigarettes, alcohol intake, serum thiocyanate levels, and cholesterol levels in the blood. Serum levels of retinol, alpha tocopherol, and retinol-binding protein were not related to any cancer site. The results of this study provide further evidence for a possible protective effect of beta carotene against lung cancer among cigarette smokers.

Adult↗
PubMed1968

Absorption of L-methionine from the human small intestine.

Absorption of L-methionine was measured in all parts of the human small intestine using transintestinal intubation and perfusion. In four normal subjects, adsorption was higher in the proximal than in the distal intestine. In two patients with nontropical sprue in relapse, there was a proximal zone of low absorption with higher absorption distally. In all parts of the small intestine, absorption showed rate-limiting kinetics as methionine concentration was increased. In normal subjects, the proximal K(m) (Michaelis constant) was more than 3 times higher than the distal, which suggests a difference in transport mechanisms between the two segments.

Adult↗
PubMedDate not supplied

Systemic lupus erythematosus in 49 Israeli males: a retrospective study.

Forty-nine male SLE patients, diagnosed and followed in seven medical centers in Israel between 1954 and 1983, were studied and analyzed retrospectively in order to determine whether the disease in males was clinically different from that reported in females both in Israel and in the world literature. The primary clinical and laboratory manifestations, the severity of the disease at the onset or at any time during the course of the disease, and the 1-15 year survival rates were not different from those described before in female SLE, although neurological involvement, nephritis, thrombocytopenia, vasculitis and hepatosplenomegaly were more prevalent in our series. However, more than half of the male patients (53%) had a benign course of disease characterized by long remissions requiring minimal or no medication. Long-term remission of serious renal involvement was observed completely in 14 and partially in 5 out of 33 patients. These results suggest that the male sex might alter the clinical course of SLE.

Adolescent↗