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Biomedical subjects

S Roy

Publications and source records attributed to S Roy.

At least 703 records · Page 39Linked to original sources
PubMed1985

Injuries of exercise.

This article presents a brief overview of a few of the conditions that may affect the exercising individual. An accurate diagnosis and a positive attitude toward exercise on the part of the physician is stressed.

Adult↗
PubMed1985

Estrogen and progestin effects on urinary calcium and calciotropic hormones in surgically-induced postmenopausal women.

Seventeen surgically-induced postmenopausal (PM) women were randomized to receive either 0.625 mg of conjugated estrogens (CE) daily or 150 mg of intramuscular depomedroxyprogesterone acetate (DMPA) every 3 months. Urinary calcium/creatinine ratios were significantly higher than ratios of premenopausal controls before treatment, but were lower in all patients 2 months after both types of treatment. Compared to controls, all PM patients had similar levels of serum PTH and 25 hydroxy vitamin D before and after treatment. As a group, PM patients had lower levels of 1.25-dihydroxyvitamin D. In 5 patients who had levels which were below the normal range, 3 were treated with CE and 2 received DMPA. These patients all had significant increases in 1,25-dihydroxyvitamin D after treatment. Serum calcitonin did not change with either CE or DMPA treatment. These data suggest that, while both CE and DMPA lower calcium excretion in PM women, the mechanism(s) for the effects of hormonal treatment on bone resorption remain unsettled.

Adult↗
PubMed1985

Effects of anti-glutamate-binding protein antibodies on synaptic membrane ion flux, glutamate transport and release, and L-glutamate binding activities.

Antibodies (Abs) raised against the L-glutamate-binding protein (GBP) purified from bovine brain were used to define the possible physiologic activity of GBP in synaptic membranes. Three processes were examined for their sensitivity to the Abs: the excitatory amino acid stimulation of thiocyanate (SCN-) flux, the transport of L-glutamic acid across the synaptic membrane, and the depolarization-induced release of L-glutamate. Only the amino acid-induced changes in ion flux were inhibited by the anti-GBP Abs. The change in membrane potential produced by exposure of synaptic membranes to excitatory amino acids was measured as the increase in the uptake of the lipophilic anion SCN-. The L-glutamate-induced SCN- influx was 40 times more sensitive to inhibition by the anti-GBP Abs than the stimulation of ion flux by kainate, and 60 times more sensitive than that produced by quisqualate. The anti-GBP Abs did not inhibit the activation of ion flux produced by N-methyl-D-aspartate. The inhibition of glutamate-stimulated ion fluxes by the Abs was complete, whereas the inhibition of L-glutamate binding to either the rat or bovine brain GBP was not. The results obtained indicated that although the majority of the anti-GBP Abs were not directed against the glutamate recognition site of the GBP and of presumed synaptic membrane receptors, they were effective in blocking the activation of receptor-associated ion channels. Thus, the GBP may be considered a component of some excitatory amino acid receptor complexes.

Animals↗
PubMed1985

Comparison of lipid and androgen levels after conjugated estrogen or depo-medroxyprogesterone acetate treatment in postmenopausal women.

Thirty-five women who had undergone a natural or surgical menopause were randomized to receive either 0.625 mg of conjugated estrogen to be ingested for 25 days each month or 150 mg of depo-medroxyprogesterone acetate intramuscularly every three months. Plasma lipids were determined before and after one year of therapy. Serum androgens were measured before and after six months of therapy. Conjugated estrogens and depo-medroxyprogesterone acetate had similar effects on plasma lipids. Cholesterol was decreased (P less than .02 for conjugated estrogen therapy and P less than .01 for depo-medroxyprogesterone acetate therapy), as was low-density lipoprotein cholesterol (P less than .02 for conjugated estrogen and P less than .05 for depo-medroxyprogesterone acetate). Conjugated estrogens also significantly increased high-density lipoprotein cholesterol (P less than .02). High-density lipoprotein cholesterol levels were unchanged after depo-medroxyprogesterone acetate therapy. Serum androgens were generally unchanged after depo-medroxyprogesterone acetate or conjugated estrogen therapy. The data from this study suggest that long-term conjugated estrogen and depo-medroxyprogesterone acetate treatment have similar effects on lipid and androgen levels except that high-density lipoprotein cholesterol was not significantly increased by depo-medroxyprogesterone acetate.

Adult↗
PubMed1985

Reliability of urinary pregnancy tests in the diagnosis of ectopic pregnancy.

Recently a new generation of urinary pregnancy tests with increased sensitivity and specificity for beta-human chorionic gonadotropin (beta-HCG) was introduced. The clinical sensitivity of seven of these tests was evaluated in patients with surgically proven ectopic pregnancy. Two enzyme-linked immunosorbent assays (Tandem Visual, Hybritech; Mod C1, Monoclonal Antibodies), with a sensitivity of 50 mIU of beta-HCG, were positive in 90% of ectopic pregnancies. The three-tube tests (Sensitex, Roche; UCG Beta Stat, Wampole; beta-Neocept, Organon), with a sensitivity of 150-250 mIU of beta-HCG, were positive in 81-85% of ectopic pregnancies. Two slide tests (UCG Beta Slide, Wampole, and Sensislide, Roche), with a sensitivity of 500-800 mIU of beta-HCG, were positive in 51-61% of ectopic pregnancies. Both the immunosorbent assays and the tube tests were statistically more sensitive than the slide tests (P less than .001). There was no statistically significant increase in sensitivity between the tube tests and the immunosorbent assays. The sensitivities of these tube tests in ectopic pregnancy are similar to those of tube tests from other manufacturers previously reported on.

Adolescent↗
PubMed1985

The role of interleukins in viral inhibition of lymphocyte mitogenesis.

Several different types of retroviruses have been shown to inhibit the lectin-driven blastogenesis of co-incubated mouse spleen cells. This abrogation of responsiveness is infection-independent, and can be obtained using live as well as UV-inactivated virus particles. Levels of both interleukin-1 (IL-1) and T-cell growth factor (TCGF) activities are greatly reduced in cultures of virus co-incubated cells. However, the inclusion of indomethacin in the culture medium, together with virus, enables responsiveness to Concanavalin A to occur at moderately efficient levels. The addition of exogenous IL-1 activity to virus co-incubated cells is also partially restorative to Con A-driven lymphocyte responsiveness, while at the same time restoring levels of detectable TCGF activity to near-control levels. Finally, the inclusion of exogenous TCGF activity also leads to efficient lymphocyte mitogenesis but does not result in increased levels of IL-1.

Animals↗
PubMed1984

Monovalent cation-induced phospholipid vesicle aggregation: effect of ion binding.

Aggregation of acidic phospholipid vesicles induced by monovalent cations was studied for vesicles of small and large sizes. It was found that there were two phases in the aggregation of large acidic phospholipid vesicles. In the initial phase, observed in the range of 0.1-0.4 M monovalent salts, aggregation took place spontaneously after a change in salt concentration; in the second phase (greater than 0.4 M salt), aggregation progressed gradually with time. The order of capability for monovalent cations to induce the initial phase of aggregation of large phosphatidylserine vesicles (more than 1000 A in diameter) was Li+ greater than Na+ greater than K+ greater than TEA+. However, for the second phase of aggregation, the order was Na+ greater than Li+ greater than K+ greater than TEA+, which was the same as that to induce massive aggregation of small phosphatidylserine vesicles (250 A in diameter). A similar reversal in the order was observed in studies of the surface potential of the phosphatidylserine monolayer. In these studies, the order of the binding strength of monovalent cations was deduced from the change in surface potential produced by successive additions of MgCl2 to the subphase solution, which contained a certain level of monovalent salt initially. These measurements were carried out with monolayers that had a range of areas per molecule. The order was Na+ greater than Li+ greater than K+ for monolayers of large area (greater than 80 A2) per molecule and was Li+ greater than Na+ greater than K+ for those of small area (less than 80 A2) per molecule.(ABSTRACT TRUNCATED AT 250 WORDS)

Cations, Monovalent↗
PubMed1984

Nitrogen-15-labeled yeast tRNAPhe: double and two-dimensional heteronuclear NMR of guanosine and uracil ring NH groups.

5N1-Labeled hypoxanthine and 1,3-15N-labeled uracil were synthesized chemically and used to prepare labeled yeast tRNAPhe biosynthetically. Maps (500 MHz) of 15N chemical shift vs. proton chemical shift were obtained, for each ring NH group, by means of INDOR (difference heterodecoupling) and also by means of a proton-observe two-dimensional method involving coherences of forbidden resonances of the NH system. Resonances of GC11, T54-m1A58, GU4, and A psi 31 were confirmed, assigned, or reassigned. psi 39 was found to be in anti conformation, not syn as previously stated. Almost all the uracil NH group resonances could be separated, but most of the GC resonances are too close even in two dimensions to be separately resolved with the observed 20-Hz 15N line width.

Guanosine↗
PubMed1984

Central and peripheral metabolites of norepinephrine and dopamine in postmenopausal women.

Urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) sulfate and glucuronide reflect, in part, central norepinephrine activity while urinary 3-methoxy-4-hydroxymandelic (VMA) reflects peripheral norepinephrine activity. Urinary MHPG and VMA were measured, together with homovanillic acid (HVA), in 20 symptomatic and seven asymptomatic postmenopausal women and 10 premenopausal control women. Urinary HVA reflects, in part, central dopamine metabolism. After nine of the symptomatic women were treated for 2 months with 0.625 mg of conjugated estrogens, urinary catecholamine measurements were repeated. Serum estrogen levels were not different in symptomatic and asymptomatic patients. Urinary MHPG, VMA, and HVA were similar in symptomatic women before and after estrogen treatment and were not different from levels of asymptomatic postmenopausal and control subjects. The ratios of MHPG:VMA, MHPG:HVA, and VMA:HVA also were similar. While body weight and estrogen did not correlate with urinary catecholamines, there was a significant positive correlation between MHPG and age in postmenopausal subjects (r = 0.56, p less than 0.005).

Adult↗
PubMed1984

Hypercalciuria in children with hematuria.

Urinary calcium excretion was assessed in 83 consecutive children with gross or microscopic hematuria in whom the presence of proteinuria or urinary-tract infection had been excluded. Twenty-three children had hypercalciuria. Clinical features that were more commonly associated with hypercalciuria included gross hematuria and a family history of urolithiasis. No clinical or pathological basis for the hematuria was determined in 22 of the 23 children with hypercalciuria or in 38 of the 60 children with normal calcium excretion. Urolithiasis developed in two children with hypercalciuria during the period of study. Oral calcium-loading tests were performed in all 23 children with hypercalciuria. Absorptive hypercalciuria was demonstrated in 10 children, whereas 13 had renal (fasting) hypercalciuria. Hematuria resolved during anticalciuric therapy in 20 of the 23 patients with hypercalciuria. We conclude that determination of urinary calcium excretion is warranted in the routine evaluation of children with hematuria.

Adolescent↗
PubMed1984

Long-term reversible contraception with levonorgestrel-releasing Silastic rods.

Subcutaneously placed Silastic capsules containing levonorgestrel are effective for 5 years and have a higher continuation rate than other methods of reversible contraception. Six 3 cm capsules are required to achieve satisfactory circulating levels of levonorgestrel. Two 4 cm covered Silastic rods containing levonorgestrel, which are easier to manufacture, insert, and remove than the capsules, produce similar in vitro release rates. This study compared clinical and metabolic effects as well as bleeding patterns in 23 women using either six capsules (n = 11) or two covered rods (n = 12). Serum levels of levonorgestrel, lipids, and lipoproteins as well as frequency of elevated progesterone levels were compared in serum samples obtained before treatment and 1, 6, 12, 18, and 24 months after insertion with the two systems. While bleeding patterns were similar for users of the two systems, rod users had slightly higher serum levels of levonorgestrel and a lower incidence of cycles with elevated progesterone levels. Therefore, rods could replace capsules as a long-term, reversible contraceptive method.

Adolescent↗
PubMed1984

Functional characteristics of L-glutamate, N-methyl-D-aspartate and kainate receptors in isolated brain synaptic membranes.

L-Glutamic acid (L-Glu) and other excitatory amino acids and amino acid analogs enhanced [35S]thiocyanate (SCN-) uptake in isolated-resealed synaptic membrane vesicles. The SCN- uptake was used as a measure of membrane depolarization to evaluate the characteristics of functional excitatory amino acid receptors in the synaptic membranes. N-Methyl-D-aspartate (NMDA) and L-Glu produced additive effects on SCN- accumulation indicating the presence of distinct L-Glu and NMDA receptors. On the other hand, kainic acid (KA) and L-Glu shared either common receptor sites or ion channels. The effects of antagonists on NMDA, L-Glu, and KA stimulation of SCN- influx were consistent with previously reported electrophysiologic observations in intact neurons.

Animals↗
PubMed1984

Coarctation of the aorta and renal artery stenosis in tuberous sclerosis.

Among neurocutaneous disorders, coarctation of the abdominal aorta and renal artery stenosis have traditionally been associated with neurofibromatosis. We report a 5-year-old girl who, during the evaluation of asymptomatic hypertension, was discovered to have bilateral renal artery stenosis, coarctation of the abdominal aorta, renal cysts and typical skin lesions of tuberous sclerosis. Renal vascular hypertension has not been reported previously in tuberous sclerosis. We conclude that the tuberous sclerosis complex should be expanded to include vascular malformations and that hypertension should not be assumed to be secondary to renal hamartomata or cysts in patients with tuberous sclerosis.

Aortic Coarctation↗