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Biomedical subjects

S Solomon

Publications and source records attributed to S Solomon.

At least 289 records · Page 16Linked to original sources
PubMed1982

Influence of protein deficiency in rats on hormonal status and cytoplasmic glucocorticoid receptors in maternal and fetal tissues.

The influence of dietary protein deficiency on maternal plasma corticosterone and progesterone levels as well as on maternal and fetal liver and lung cytoplasmic glucocorticoid receptors has been studied in Sprague-Dawley rats during the last 3 days of gestation. Plasma corticosterone levels of control but not protein-deficient rats increased on days 20 and 21 of gestation; corticosterone levels of protein-deficient rats decreased on day 21 of gestation. Maternal adrenalectomy caused only a moderate decrease in corticosterone levels in both groups of pregnant rats. Fetal corticosterone levels of the two groups of rats were similar. Progesterone levels were consistently lower in protein-deficient than in control animals from day 20 of gestation until 2-12 h after parturition. There were no differences in the binding of [3H]dexamethasone to liver cytosol of non-pregnant control and protein-deficient rats. However, receptor levels were lower in pregnant controls than in pregnant protein-deficient rats. Maternal protein deficiency led to an increase in fetal liver glucocorticoid receptor levels but exerted no significant effect on receptor levels in fetal lung. It is suggested that lower levels of plasma corticosterone and progesterone and high levels of liver glucocorticoid receptors in protein-deficient rats might be related to some of the adverse consequences of maternal malnutrition on fetal development.

Animals↗
PubMed1982

Indications and methods for therapeutic apheresis.

Technological advancements in the biomedical field have recently afforded the clinician opportunities to safely treat disease processes that previously defied conventional medicine. Therapeutic apheresis is one such application of these advancements and offers potential benefit to patients suffering from various hematological, renal, rheumatic, and neuromuscular disorders. Research is continually being done to clearly define the role of this new therapy. New protocols are continually being developed and evaluated in the attempt to find out and control the variables necessary to nesure that each disease process is treated in the most effective manner possible.

Autoimmune Diseases↗
PubMed1982

Excretion of ammonia by rat kidney during metabolic alkalosis.

In rat kidney, proximal tubular and final urinary ammonia concentration are finite. They are lower in animals with metabolic alkalosis than in controls. A positive correlation between ammonia concentration and water removal (as indicated by fluid to plasma ratios for inulin) was found. A comparison of tubular fluid to plasma concentration ratios for inulin and ammonia indicates that more ammonia enters proximal tubular fluid than appears in the final urine. These observations indicate that ammonia is probably secreted primarily at the level of the proximal tubule and then undergoes reabsorption at distal sites of the nephron.

Alkalosis↗
PubMed1981

Isolation and characterization of corticotropin- and melanotropin-related peptides from the neurointermediary lobe of the rat pituitary by reversed-phase liquid chromatography.

A novel procedure utilizing reversed-phase high-performance liquid chromatography for the extraction and purification of peptides from biological tissues has been applied to the isolation of corticotropin-like intermediary lobe peptide (CLIP) and alpha-melanocyte-stimulating hormone (alpha-MSH) from the neurointermediary lobe of the rat pituitary. The isolation and characterization of two major forms of CLIP and two major forms of alpha-MSH are described. The isolated peptides have been identified by using enzymatic digestions and peptide mapping. The main form of ClIP is a peptide which has been modified by phosphorylation of the serine residue at position 31. This is the first peptide of endocrine origin reported to be modified in such a manner. A non-phosphorylated form of CLIP was also present at lower concentrations. The main form of alpha-MSH was found to be N,-O-diacetyl-alpha-MSH, with the more familiar mono-N-acetyl-alpha-MSH present to a much smaller extent. Thus, in the rat neurointermediary lobe, the two main corticotropin-related peptides present are mostly in modified forms which are the result of posttranslational modifications. It is only by the use of methodology such as that described in this paper that small alterations in peptide structure may be identified.

Adrenocorticotropic Hormone↗
PubMed1981

Isolation and analysis of human parathyrin in parathyroid tissue and plasma. Use of reversed-phase liquid chromatography.

Reversed-phase liquid chromatography techniques have been used to extract and purify human parathyrin from parathyroid adenomas and to analyse the circulating forms of human parathyrin in plasma. Both the supernatant from tissue homogenates, and plasma were extracted with octadecylsilyl-silica (ODS-silica) in a batch procedure. Extracts were subjected to reversed-phase high-pressure liquid chromatography (h.p.l.c.) employing solvent systems composed of aqueous acetonitrile containing trifluoroacetic acid or heptafluorobutyric acid as hydrophobic ion-pairing reagents. The volatile solvents facilitated the radioimmunoassay, bioassay in vitro and amino acid analysis of column fractions and permitted monitoring for u.v. absorbance at 210nm. Isolated glandular parathyrin was found to be homogeneous by sodium dodecyl sulphate/urea/polyacrylamide-gel electrophoresis, to have an amino acid composition conforming to that of human parathyrin-(1--84)-tetraoctacontapeptide and to be bioactive in both renal adenylate cyclase and cytochemical bioassays. ODS-silica extraction permitted examination of large plasms samples by reversed-phase h.p.l.c., facilitating the resolution of the various circulating molecular forms of parathyrin according to their hydrophobic character. Because of its rapidity, excellent recovery and high resolving power, the methodology utilized is uniquely suited to the purification and analysis of parathyrin in tissues and body fluids.

Adenoma↗
PubMed1981

Biosynthesis of phosphorylated forms of corticotropin-related peptides.

Phosphorylated forms of corticotropin[ACTH (1-39)], corticotropin-like intermediary lobe peptide[CLIP, ACTH (18-39)], and the common precursor for ACTH and beta-lipotropin (beta-LPH) have been identified in extracts of rat pituitaries, 32P-Labeled inorganic phosphate was successfully incorporated into ACTH (1-39), CLIP, and the ACTH/beta-LPH precursor in rat neurointermediary lobe explants and into ACTH (1-39) in isolated rat anterior pituitary cells. After peptidase digestion of the labeled CLIP and ACTH, the radioactive phosphate was recoverable as O-phosphoserine. The serine residue at position 31 was the only amino acid found to be phosphorylated in CLIP and ACTH (1-39). The unphosphorylated forms of both peptides were also synthesized. The demonstration of he incorporation of [32P]phosphate into CLIP, ACTH (1-39), and the ACTH/beta-LPH precursor is consistent with the hypothesis that, within the rat intermediary lobe, phosphorylated CLIP is derived from a phosphorylated form of the common precursor, with phosphorylated ACTH (1-39) acting as a biosynthetic intermediate.

Adrenocorticotropic Hormone↗
PubMed1981

pH and temperature dependence of glutamine uptake, carbon dioxide and ammonia production in kidney slices from acidotic rats.

1. The effects of medium pH and temperature on glutamine uptake, NH3 production and CO2 production were examined using kidney cortex slices from normal and acidotic rats. 2. Uptake of glutamine by kidney slices from normal rats shows a pH optimum of 7.5 at 25 degrees C and 7.3 at 37 degrees C. Uptake is optimal, however, at a constant OH-/H+ ratio of 10. 3. In slices from acidotic rats greatest uptake was at pH 6.8 at 25 degrees C and 6.6 at 37 degrees C. Optimal OH-/H+ ratio was 0.4 and constant at both temperatures. 4. CO2 production from glutamine was greatest at pH 7.0 at 37 degrees C in slices from control rats. No pH optimum was detected at 25 degrees C. With slices from acidotic animals, optimal pH for CO2 production became identical with that for uptake. 5. Both basal and glutamine-stimulated NH3 production showed no optimal pH but were significantly higher in slices from acidotic rats compared with those from controls. 6. Dependence of glutamine penetration on optimal OH-/H+ ratio is considered to reflect a general membrane phenomenon which is produced by either an increase in carrier-substrate complexes or an increase in the number of carriers at this ratio. 7. Cellular penetration of glutamine does not appear to be a limiting factor in production of NH3 in vitro.

Acid-Base Equilibrium↗
PubMed1980

Separation of collagen cyanogen bromide-derived peptides by reversed-phase high-performance liquid chromatography.

A new technique for separation of the CNBr cleavage products of collagen is described. It involves the use of a 30 nm pore reversed-phase high-performance liquid chromatography column eluted with a linear gradient of acetonitrile/water containing 0.01 M-heptafluorobutyric acid. The separation of type I, type II and type III CNBr peptides is described. Resolution is particularly good for the low-molecular-weight peptides. The method is fast, quantitative and sensitive, and the complete volatility of the eluent facilitates the recovery of the separated peptides.

Acetonitriles↗
PubMed1980

Supervision in liaison and consultation psychiatry.

This paper reports special problems and techniques of teaching liaison and consultation psychiatry to psychiatric residents. It has become apparent that traditional methods of resident training are inadequate, and that specialized techniques of supervision are required to help the resident deal with the unique aspects of the liaison and consultation environment. Specific recommendations are made and discussed.

Countertransference↗
PubMed1980

Behavior control over aversive events: does control that requires effort reduce anxiety and physiological arousal?

Although it has been suggested that the ability to control (avoid) an aversive event will reduce arousal, it may be that the effort associated with exercising the control will offset the arousal reduction associated with avoidance. To determine whether the amount of effort required to control an aversive event influenced the amount of anxiety and physiological arousal associated with the aversive event, 89 subjects participated in a 3 (unavoidable threat, avoidable threat, no threat) X 2 (high-effort task performance, low-effort task performance) X 2 (anticipation period, performance period) factorial experiment. The results indicated that (a) the aversive event (threat of electrical shock) increased subjects' anxiety and physiological arousal; (b) exercising control was effective for decreasing subjects' anxiety to the non-threat level but only when low effort was required; (c) the prospect of control decreased subjects' physiological arousal to the no-threat level while the subjects were waiting to exercise control over the aversive event; however, (d) while actually exercising the control, subjects showed high physiological arousal like that of subjects who could not control the event. These findings impose important qualifications on the speculations concerning the influence of control.

Anxiety↗