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Biomedical subjects

S Solomon

Publications and source records attributed to S Solomon.

At least 325 records · Page 18Linked to original sources
PubMed1978

Biosynthesis of prostaglandins and thromboxane B2 by fetal lung homogenates.

The conversion of arachidonic acid to prostaglandins (PG's) and thromboxane B2 (TXB2) was investigated in homogenates from fetal and adult bovine and rabbit lungs. Adult bovine lungs were very active in converting arachidonic acid (100 microgram/g tissue) to both PGE2 (10.7 microgram/g tissue) and TXB2 (6.2 microgram/g tissue. Smaller amounts of PGF2alpha (0.9 microgram/g) and 6-oxoPGF1alpha were formed. Homogenates from fetal calf lungs during the third trimester of pregnancy were quite active in converting arachidonic acid to PGE2, but formed very little TXB2, PGF2alpha or 6-oxoPGF1alpha. Homogenates from rabbit lungs converted arachidonic acid (100 microgram/g) mainly to PGE2, both before and after birth. The amount of PGE2 formed increased during gestation to a maximum of about 6 microgram/g tissue at 28 days of gestation. It then decreased to a minimum (1.5 microgram/g) which was observed 8 days after birth, followed by an increase to about 4 microgram/g in older rabbits.

Animals↗
PubMed1978

Isolation fo 15alpha-hydroxypregnenolone and 15alpha-hydroxydehydroisoandrosterone from human pregnancy urine.

15alpha-Hydroxydehydroisoandrosterone and 15alpha-hydroxypregnenolone were isolated from hydrolyzed extracts of human late pregnancy urine and identified by means of the isotope dilution technique. In two separate determinations the excretion rate of 15alpha-hydroxydehydroisoandrosterone was found to be 1.7 and 3.2 microgram per day while that of 15alpha-hydroxypregnenolone was 1.7 and 2.9 microgram per day. It is postulated that 15alpha-hydroxydehydroisoandrosterone might serve as a precursor of 15alpha-hydroxylated estrogens already isolated from late pregnancy urine. Similarly, 15alpha-hydroxypregnenolone might be an endogenous precursor of 15alpha-hydroxyprogesterone.

17-alpha-Hydroxypregnenolone↗
PubMed1978

Formation of 15alpha-hydroxyestriol and 15alpha-hydroxyestradiol from C19 15alpha-hydroxylated precursors in human pregnancy.

A mixture of 3H-15alpha-hydroxyandrostenedione and 14C-15alpha-hydroxydehydroisoandrosterone was injected intravenously into two subjects in the third trimester of pregnancy and, in a second study, directly into two fetuses in utero during transfusion for erythroblastosis fetalis. The urine was collected for 4-5 days and steroid conjugates in the urine were hydrolyzed into sulfate and glucosiduronate fractions. From the glucosiduronate fraction 15alpha-hydroxyestriol, 15alpha-hydroxyestradiol, 15alpha-hydroxyandrostenedione and 15alpha-hydroxydehydroisoandrosterone were isolated. No metabolites were identified in the sulfate fraction of the urine. A marked difference was observed in the metabolism of 15alpha-hydroxyandrostenedione and 15alpha-hydroxydehydroisoandrosterone which is dependent on the route of administration of the substrates. Both substrates were converted to 15alpha-hydroxyestriol and 15alpha-hydroxyestradiol, and the 3H/14C ratios and percentage conversions suggest that 15alpha-hydroxyandrostenedione seems to be a better precursor of the urinary 15alpha-hydroxylated estrogens than 15alpha-hydroxydehydroisoandrosterone. The 3H/14C ratios also suggest that 15alpha-hydroxydehydroisoandrosterone was converted to 15alpha-hydroxyestriol via 15alpha-hydroxyandrostenedione, and that the formation of 15alpha-hydroxyestradiol from 15alpha-hydroxydehydroisoandrosterone via 15alpha-hydroxyandrostenedione is a pathway of minor importance. Finally, 15alpha-hydroxydehydroisoandrosterone was recovered from the urine only when the precursors were injected into the maternal circulation. Also, an unknown metabolite containing only 14C was detected in the glucosiduronate fraction of the urine of each subject.

Androstenedione↗
PubMed1978

Control of respiration as a means of controlling responses to threat.

After a 30-minute rest period, (a) subjects in a respiration tracing condition began replicating their breathing patterns from the rest period; (b) subjects in an attention tracing condition participated in a comparable task that did not involve the control of respiration; and (c) subjects in a no-tracing condition were not assigned to perform any task. After the tracing manipulation was introduced, half of the subjects were assigned to a threat condition and informed that they would receive a series of painful electric shocks, whereas the other subjects were assigned to a no-threat condition and informed that they would receive red light stimulation. Analyses of heart rate and self-report data indicated that (a) the threat manipulation was effective; (b) controlling respiration did not reduce subjects' stress responses; and (c) subjects in the no-tracing condition were the only stressed subjects to show decreases in physiological arousal over time, an effect that may have been due to their use of a cognitive coping strategy (situation redefinition). These findings do not provide evidence that control of respiration is an effective strategy for controlling stress but do suggest that, when not interferred with, subjects can employ relatively effective, self-generated cognitive coping strategies.

Adaptation, Psychological↗
PubMed1978

Precursor role of 15alpha-hydroxyestradiol and 15alpha-hydroxyandrostenedione in the formation of estetrol.

Studies were designed to elucidate the origin of estetrol (15alpha-hydroxyestriol (estra-1,3,5(10)triene-3,15alpha,17beta-tetrol) or E4) during late human pregnancy. 3H-Labelled 15alpha-hydroxyestradiol (3,15alpha-dihydroxyestra-1,3,5(10)-trien-17-one or 15E2) and 14C-labelled 17beta-estradiol (estra-1,3,5(10)-triene-3,17beta-diol or E2) were infused into the fetus during transfusion in utero for erythroblastosis fetalis, and in another study the same substrates were injected intravenously into the maternal circulation. In a third study, 3H-labelled 15alpha-hydroxyandrostenedion (15alpha-hydroxyandrost-4-ene-3,17-dione or 15delta4) and 14C-labelled E2 were infused into the fetus. Maternal urine was collected for 5--6 days, and after Glusulase hydrolysis, the following metabolites were isolated: estriol (estra-1,3,5(10)-triene-3,16alpha,17beta-triol or E3) containing 14C only and 15alpha-hydroxyestrone (3,15alpha-dihydroxyestra-1,3,5(10)-trien-17-one or 15E1), 15E2, and E4, all containing both labels. From the isotope content of these metabolites, it was concluded that E4 was derived from both fetal E2 and 15delta4 and only partially via 15E2. When administered to the fetus E2 and 15delta4 contributed approximately equal amounts to urinary E4. The yield of 15alpha-hydroxylated estrogens from E2 injected into the mother was very low indicating the predominantly fetal origin of the 15alpha-hydroxylase. 15delta4 was a better precursor than E2 for urinary 15E2.

Androstenedione↗
PubMed1978

Contamination of prolactin preparations by antidiuretic hormone and oxytocin.

Since impurities consisting of neurohypophysical hormones in prolactin powder may be responsible for the vascular and renal effects attributed to prolactin, rat (NIH-RP-1), ovine (NIH-P-S-10, S-12), and bovine (NIH-P-B4) prolactin preparations were examined for their content of ADH and oxytocin by rat antidiuresis, milk-ejection, and blood pressure assays. Activities were identified as due to ADH or oxytocin by incubation of prolactin solutions with antisera against ADH, oxytocin, and prolactin, or with pregnancy plasma. The ADH content of rat, ovine (P-S-10, P-S-12) and bovine prolactin was found to be 104.5 +/- 7.1 (means +/- SE), 2.5 +/- 0.2, 1.6 +/- 0.1, and 1.6 +/- 0.5 mU/mg powder, respectively; the corresponding values for oxytocin content were 155.3 +/- 3.5, 1.2 +/- 0.1, 0.5 +/- 0.1, and 1.2 +/- 0.01 mU/mg powder, respectively. Because antidiuretic, milk-ejection, and blood pressure activities of the various prolactins were eliminated after incubation with antisera against ADH and oxytocin, or with pregnancy plasma, but not with prolactin antisera, it is concluded that the reported vascular and renal prolactin effects are attributable to ADH contamination of the prolactin preparation rather than to the prolactin molecule itself. These findings have implications for renal and vascular prolactin research.

Animals↗
PubMed1978

Changes in structure and function of rat kidney slices produced by low sodium.

The effects of a low Na medium on PAH transport, renal morphology, and acetate stimulation of PAH transport have been studied. Low Na inhibits PAH uptake and induces vacuolar formation in tubular cells. Both processes are reversible by reincubating in a high Na medium. Vacuolization appears temperature dependent being much greater at 37 than at 25 degrees C. Acetate uptake consists of a passive and an active component, neither of which is sodium dependent. Acetate stimulation of PAH uptake does, however, require Na. This latter observation suggests that Na may act by altering cell metabolism.

Acetates↗
PubMed1978

Dependence of glutamine metabolism and ammonia synthesis on sex in rat kidney slices.

The uptake and metabolism of glutamine, production of ammonia and consumption of O2 were studied in kidney slices isolated from mature, gonadectomized and newborn male and female rats in the presence of 0.05, 0.5, 2 and 5 mM-glutamine. Slices isolated from mature intact female rats showed significantly greater conversion of glutamine into CO2 and NH3 without any change in the total uptake of glutamine when compared with all other experimental groups. No difference in O2 consumption was found between mature male and female animals. Ovariectomy reduced glutamine metabolism, NH3 production and O2 consumption without any effect on the total uptake of glutamine. In contrast, castration did not significantly affect glutamine metabolism and production of NH3 but did reduce O2 consumption. Newborn (20- to 21-day-old) rats showed no sex-dependent differences in glutamine uptake and metabolism, production of NH3 and consumption of O2, but values for all these parameters were lower in kidney slices from newborn animals than in kidney slices from mature, intact or gonadectomized male and female rats. It is concluded that in female rats, metabolism of glutamine and production of NH3 may be influenced by ovarian sex hormones.

Aging↗