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Biomedical subjects

S Roy

Publications and source records attributed to S Roy.

At least 811 records · Page 45Linked to original sources
PubMed1980

Termination of early gestation with a single vaginal suppository of (15S)-15-methyl-prostaglandin F2alpha methyl ester.

Abortion was induced in 20 women who were less than 49 days pregnant with a vaginal suppository containing 3.0 mg (15S)-15-methyl-prostaglandin F2alpha methyl ester. Peripheral serum levels of (15S)-15-methyl F2alpha free acid, beta hCG and progesterone were measured before, during the 10 hours after treatment and over the next 14 days. Eighteen of the subjects had a complete follow-up: ten were aborted (53%), three had incomplete abortions and five were failures. There was a correlation between serum levels of F2alpha (15S)-15-methyl-prostaglandin F2alpha free acid, and the incidence of success. Progesterone was significantly reduced in all three groups of subjects and, therefore, could not be utilized to judge the success of the procedure. A small but insignificant reduction of betahCG occurred in all subjects regardless of outcome during the ten-hour observation period. Since minor side effects of diarrhea and vomiting occurred in less than half of the aborted and only a few of the not aborted subjects, a larger amount of drug might improve the success rate.

Abortion, Induced↗
PubMed1980

The action of leukotriene B4 (LTB4) on the lung.

The actions of leukotriene B4 (LTB4), a member of a newly discovered pathway of metabolism of arachidonic acid, were investigated both on the guinea-pig perfused lung preparation and on the parenchymal strip and compared to histamine and Slow Reacting Substance of Anaphylaxis (SRS-A). LTB was prepared from human polymorphonuclear leukocytes, extracted and purified by chromatography (Silicic acid and HPLC) and its purity was determined by gas chromatography and mass spectrometry. LTB4 is three times more potent than histamine (molar concentration) to contract the parenchymal strips and the contraction to LTB4 as well as to SRS-A lasted longer. The contraction to LTB4 is blocked by indomethacin (20 micrograms/ml), reduced by polyphloretin phosphate (50 micrograms/ml) and unaffected by FPL-55712 (1 micrograms/ml). Following its injection in the pulmonary artery of a perfused lung, LTB4 (1 microgram) induced the release of RCS (Rabbit Aorta Contracting Substance: a mixture of prostaglandins and thromboxanes) which can be abolished by indomethacin (1 microgram/ml). These findings suggest (a) that in the lung, LTB4 is a myotropic agent three times more powerful than histamine (b) that LTB4 stimulated a receptor which is different of histamine of SRS-A receptors, and (c) that its contractile action in the lung is mediated by prostaglandins and thromboxanes.

Animals↗
PubMed1980

Hydrophobic basis of packing in globular proteins.

The self-assembly of globular proteins is often portrayed as a nucleation process in which the hydrogen bonding in segments of secondary structure is the precondition for further folding. We show here that this concept is unlikely because both the buried interior regions and the peptide chain turns of the folded protein (i.e., inside and outside) are predicted solely by the hydrophobicity of the residues, taken in sequential order along the chain. The helices and strands span the protein, and this observed secondary structure is seen to coincide with the regions predicted to be buried from hydrophobicity considerations alone. Our evidence suggests that linear chain regions rich in hydrophobic residues serve as small clusters that fold against each other, with concomitant or even later fixation of secondary structure. A helix or strand would arise in this folding process as one of a few energetically favorable alternatives for a given cluster, followed by a shift in the equilibrium between secondary structure conformers upon cluster association. the linera chain hydrophobicity alternates between locally maximal and minimal values, and these extrema partition the polypeptide chain into structural segments. This partitioning is seen in the x-ray structure as isodirectional segments bracketed between peptide chain-turns, with the segments expressed most often as helices and strands. the segment interactions define the geometry of the molecular interior and the chain-turns describe the predominant features of the molecular coastline. The segmentation of the molecule by linear chain hydrophobicity imposes a major geometric constraint upon possible folding events.

Amino Acids↗
PubMed1980

Demonstration of luteinizing hormone/human chorionic gonadotrophin receptor-binding inhibitor in aqueous extracts of frozen human corpus luteum.

Aqueous extracts of frozen human corpora lutea were tested for the presence of an inhibitor of luteinizing hormone-receptor site binding (LHRBI) and for the subsequent effect on the stimulatory response of luteinizing hormone (LH) on progesterone synthesis by sheep ovarian cells. In the presence of human corpus luteum extract of normal menstrual cycle (30,000-g supernatant), the binding of 125I human chorionic gonadotrophin (hCG) to granulosa and luteal cells of sheep ovaries was markedly reduced, but the ability of rat testicular LH receptors to bind labelled hCG was less affected. However, extracts of corpora lutea of the first trimester of pregnancy appeared to be less inhibitory on the binding of LH/hCG to ovarian cells and had no effect on the binding of rat testicular cells compared to those of normal menstrual cycle. Addition of both extracts separately inhibited the LH-stimulated in vitro progesterone synthesis by granulosa cell cultures and by incubated sheep corpus luteum slices. These findings provide evidence for the presence of LHRBI in human corpus luteum.

Animals↗
PubMed1980

Schwannoma of the brain stem: case report.

A case of intramedullary schwannoma of the brain stem is reported, and its possible origin discussed. The importance of a biopsy in brain-stem tumors is emphasized.

Adolescent↗
PubMed1980

Bacteremia in post-Cesarean section endomyometritis: differential response to therapy.

Presented are blood culture results obtained from 200 patients with post-cesarean section endomyometritis treated with either penicillin-gentamicin or clindamycin-gentamicin. Their clinical course is correlated to their blood culture results by the fever index. Fifty-three percent of the 60 organisms isolated from 48 patients were anaerobic bacteria. Patients from whose blood cultures anaerobic bacteria were recovered had higher fever indexes than did those with aerobic isolates (P less than .05). Clindamycin-gentamicin patients from whose blood cultures anaerobic organisms were isolated had less febrile morbidity than did comparable penicillin-gentamicin patients. Patients with Bacteroides fragilis bacteremia had the highest fever indexes overall. Therefore, patients with post-cesarean section endomyometritis have less febrile morbidity if they are initially treated with a drug effective against anaerobic bacteria, especially B fragilis.

Anti-Bacterial Agents↗
PubMed1980

Interaction of dantrolene with the hepatic mixed function oxidase system.

Dantrolene pretreatment of rats (100 mg/kg/day for five days) causes a fifty percent decrease in hepatic mixed function oxidase (MFO) system activity and a fifty percent decrease in cytochrome P450 content. Recovery of hepatic MFO system activity after discontinuing dantrolene therapy is slow (only sixty-three percent recovery in ten days) and greatly exceeds the half-life of dantrolene in rats (thirty-one minutes). The inactivation of the hepatic MFO system and the slow-recovery of its activity is apparently caused by dantrolene binding and forming a stable complex with hepatic proteins. 14C-dantrolene (1.0 mg/kg) administered i.v. eighteen hours before sacrificing the rats forms a stable complex with hepatic microsomal and soluble proteins. The dantrolene binding to hepatic proteins is decreased by phenobarbital pretreatment and is enhanced by diethylmaleate pretreatment.

Animals↗
PubMed1979

"Incessant ovulation" and ovarian cancer.

A case-control study of 150 ovarian cancer patients under the age of 50 and individually matched controls was done to study the influence of fertility and oral contraceptive use on the risk of ovarian cancer. The risk decreased with increasing numbers of live births, with increasing numbers of incomplete pregnancies, and with the use of oral contraceptives. These three factors can be amalgamated into a single index of protection--"protected time"--by considering them all as periods of anovulation. The complement of protected time--viz., "ovulatory age", the period between menarche and diagnosis of ovarian cancer (or cessation of menses) minus "protected time"--was strongly related to risk of ovarian cancer. Other factors found to be associated with increased ovarian cancer risk were obesity, cervical polyps, and gallbladder disease. Women who had an "immediate" intolerance to oral contraceptive use had a fourfold increased risk of ovarian cancer. 7 patients, but no controls, could recall a family history of ovarian cancer.

Abortion, Spontaneous↗
PubMed1979

Comparison of three different models of the copper T intrauterine contraceptive device.

A random sequential comparative study of three models of the Copper T intrauterine contraceptive device (IUD) was undertaken in 1,792 women. For 7 months, the TCu 300 and TCu 220C were randomly inserted, and then the TCu 380A and 220C were randomly inserted for the next 12 months. The log-risk method of life-table analysis of event rates was performed at the end of each of the first 3 years of use of each device. The TCu 380A had the lowest pregnancy rate during each year of use, although the difference was not significant. At the end of each of the first 2 years, the TCu 300 was removed significantly less than the TCu 220C and TCu 380A for bleeding and pain. At the end of three years, the rates of removal for bleeding and pain for the TCu 380A and TCu 300 were similar and lower than that for the TCu 220C, but the overall difference was not significant. There were no differences among the devices for any other relevant use-related reasons. The TCu 380A was removed for other medical reasons significantly more frequently than the other devices at the end of 2 and 3 years. Adjusting for parity did not alter the results. The findings of this study suggest that the copper sleeves along the horizontal arms together with copper wire on the vertical arm in the TCu 380A model provide greater protection against intrauterine pregnancy, whereas the copper sleeves along the vertical arm as in the TCu 220C caused increased removals for bleeding and pain. The TCu 380A should be studied in a larger number of patients for a longer period of time to determine its clinical effectiveness. It may become the IUD of choice for all women irrespective of parity.

Female↗
PubMed1979

A comparison of clindamycin-gentamicin and penicillin-gentamicin in the treatment of post-cesarean section endomyometritis.

A random comparison of clindamycin-gentamicin (C-G) and penicillin-gentamicin was made in 200 women who developed endomyometritis following cesarean section. All pretreatment profiles indicated similar populations. The clinical response was more favorable in the women receiving clindamycin-gentamicin. The implications of these results upon clinical practice is discussed.

Adult↗