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Biomedical subjects

R Solomon

Publications and source records attributed to R Solomon.

At least 91 records · Page 5Linked to original sources
PubMed1985

Atriopeptin stimulation of rectal gland function in Squalus acanthias.

The rectal gland of the shark plays a significant role in the homeostasis of extracellular volume. Regulation of rectal gland function is under hormonal control, but the precise identity of the humoral mediator is unknown. Atriopeptin stimulates rectal gland chloride secretion in vivo. This stimulation of epithelial transport is accompanied by systemic and local hemodynamic effects. Atriopeptin also stimulates chloride secretion by the in vitro perfused rectal gland, an effect that is not accompanied by hemodynamic changes. Extracts of shark heart, but not muscle, brain, kidney, or intestine, contain a heat-stable trypsin-sensitive substance capable of in vitro stimulation of rectal gland chloride secretion. Electron micrographic analysis reveals multiple neurosecretory-like granules in atrial cardiocytes that are only rarely seen in ventricular cardiocytes. By using the in vitro perfused gland as a biologic assay, serum obtained after extracellular volume expansion reveals the presence of a rectal gland stimulatory factor that is not present in serum before expansion. These results are consistent with the hypothesis that atriopeptin is present in shark cardiocytes and is released during volume expansion. The atriopeptin stimulates rectal gland chloride secretion, providing a negative feedback mechanism for the regulation of extracellular volume.

Animals↗
PubMed1985

Stress fractures of the second metatarsal involving Lisfranc's joint in ballet dancers. A new overuse injury of the foot.

We reviewed the cases of four female ballet dancers with a stress fracture of a type that has not been reported previously. This fracture occurs in the proximal portion of the second metatarsal and involves the volar and medial aspects of Lisfranc's joint. A differential diagnosis of pain in the middle part of the foot in a dancer should include a consideration of this entity, which can be very difficult to diagnose on initial assessment. Oblique radiographs, tomograms, and a bone scan may be necessary to confirm the diagnosis. With early recognition and diagnosis, in three of the four patients the fracture healed with immobilization and modified training. One patient required surgical resection because of persistent non-union of the necrotic fracture fragment.

Adolescent↗
PubMed1984

Relation of titers of antibodies to CMV in blood donors to the transmission of cytomegalovirus infection.

Titers of antibody to cytomegalovirus (CMV) of 529 persons whose blood had been supplied to 51 selected patients who underwent open-heart surgery were determined by indirect hemagglutination (IHA) and IgM-specific indirect immunofluorescence (IFA). Twenty-eight patients showed evidence of active CMV infection after transfusion (seroconversion or a fourfold rise in titer by IHA), whereas 23 showed no serological change. Patients with active CMV infections had received, on average, a greater number of blood units (12.9 vs. 7.9), of which more were seropositive (6.9 vs. 3.5), than did patients who showed no serological change. Those seropositive units of blood that had been transfused into the group that showed evidence of active infection, however, had a lower geometric mean titer than did those transfused into the group that showed no serological change (1:654 vs. 1:1,360). Seven (1.3%) of the 529 blood donors had CMV-specific IgM titers (by IFA) of greater than or equal to 1:16; each of the seven recipients of their blood subsequently showed evidence of active CMV infection. This study suggests that donor blood with high IHA titers may prevent transmission of CMV infection, whereas blood from donors with IgM antibody to CMV may transmit CMV.

Antibodies, Viral↗
PubMed1984

In vivo effect of volume expansion on rectal gland function. I. Humoral factors.

The spiny dogfish Squalus acanthias responds to volume expansion by increasing the rate of chloride secretion by its rectal gland. The response is elicited by intravascular infusion of either isotonic shark Ringer solution, a 1 M hypertonic sodium chloride solution, or an isotonic hyponatremic solution containing equal volumes of shark Ringer solution and 10% mannitol. The effect of volume expansion was evoked in explanted glands connected to a host fish only by the arterial supply, indicating that the response is mediated by a humoral factor. The explanted gland responded to theophylline (2.5 X 10(-3) M) and adenosine 3',5'-cyclic monophosphate (5 X 10(-4) M) by increasing the rate of secretion of chloride by an amount similar to that induced by volume expansion of the perfusing fish. Theophylline at concentrations (10(-6) to 5 X 10(-5) M) that are known to inhibit the effect of adenosine in isolated perfused glands failed to inhibit the effect of volume expansion on explanted glands. Somatostatin (4.5 X 10(-6) M), which inhibits the effect of vasoactive intestinal peptide (VIP) in the isolated perfused gland, completely prevented the secretory response to volume expansion in explanted glands. Volume expansion is a major stimulus for chloride secretion by the rectal gland. The effect is mediated by a humoral factor that appears to be VIP.

Animals↗
PubMed1983

A double-blind study of oxprenolol once and twice daily in hypertensive patients.

In a randomized double-blind study of 175 patients with mild-to-moderate hypertension, oxprenolol hydrochloride (160-480 mg) given once daily was compared with the same drug given twice daily for efficacy, safety, and tolerability. Of these patients, 123 (58 receiving the once daily regimen and 65 receiving the twice daily regimen) were included in the analysis of efficacy. Both groups showed similar significant (p less than 0.01) reductions in mean blood pressure during the 6-week titration period and for the remainder of the trial. A comparison of mean standing diastolic blood pressure and supine systolic and diastolic blood presses showed no significant difference between groups during the fixed dosage period. The number of patients reporting adverse experiences was not significantly different for the two regimens. Plasma triglycerides increased in both groups, but there were no other laboratory abnormalities related to treatment. This study shows that oxprenolol given once daily is effective, safe, and well tolerated in the treatment of mild-to-moderate hypertension.

Adult↗
PubMed1983

Effect of age and diet on insulin secretion and insulin action in the rat.

The effects of aging on various aspects of insulin secretion and action were studied in male Sprague-Dawley rats, maintained from 1 1/2 to 12 mo of age on conventional rat chow, sucrose-rich, or calorie-restricted diets. In chow-fed rats, islet volume increased as the animals grew from 1 1/2 to 12 mo of age, but glucose-stimulated insulin secretion (per volume islet) declined over the same interval. In addition, in vivo insulin-stimulated glucose utilization fell in these rats. However, the plasma insulin response to an oral glucose challenge was sufficient to prevent frank decompensation of glucose tolerance (presumably due to an increase in total pancreatic endocrine cell mass). All these changes, with the exception of the decline in glucose-stimulated insulin secretion per volume islet, were accentuated by feeding sucrose. Thus, 12-mo-old sucrose-fed rats had larger islets and higher plasma insulin levels in response to an oral glucose challenge, and the rats were more insulin-resistant than chow-fed rats. However, glucose-stimulated insulin release per volume islet was similar in 12-mo-old chow-fed and sucrose-fed rats. In contrast, calorie restriction led to an amelioration in all but one of the age-related changes, i.e., islets from calorie-restricted rats were comparable in size to those of 2-mo-old rats, the animals had lower plasma insulin levels in response to an oral glucose load, and they were less insulin resistant than the other two groups of 12-mo-old rats. On the other hand, glucose-stimulated insulin secretion per volume islet was similar to that of the other 12-mo-old rats. These results suggest that aging leads to marked changes in both insulin secretion and insulin action. The decline in glucose-stimulated insulin secretion per unit endocrine pancreas appears to be an inevitable consequence of the aging process. In contrast, the age-related changes in islet size, insulin response to a glucose load, and in vivo insulin-stimulated glucose uptake are extremely responsive to variations in amount and kind of calories. DIABETES 32:175-180, February 1983.

Aging↗
PubMed1983

Demonstration of a relationship between level of physical training and insulin-stimulated glucose utilization in normal humans.

The relationship between level of physical training and in vivo insulin-stimulated glucose utilization was investigated in 33 healthy nonobese subjects. Status of physical training was estimated by maximal oxygen consumption (VO2 max) during graded bicycle ergometry, and insulin action by the insulin clamp technique. Within the study population we defined a significant (r = 0.63, P less than 0.001) correlation between these two variables. This relationship was independent of age and obesity and accounted for over 40% of the variance in insulin-stimulated glucose utilization among these subjects. In addition, significant correlations existed between VO2 max and the plasma glucose (r = -0.35, P less than 0.05) and insulin (r = -0.37, P less than 0.05) responses to an oral glucose load. These results suggest that differences in level of physical training play a regulatory role in control of in vivo insulin action.

Adult↗
PubMed1982

Functional homogeneity of pancreatic islets of aging rats.

Islest from different regions of pancreases of aging rats were compared for size and variations of response to glucose stimulation. The results show that pancreatic islets from the ventral-duodenal and splenic regions of 12-mo-old retired breeder. Spraque dawley rats are comparable in all respects measured: thus, pancreatic regional differences cannot explain the age-associated reduction in beta cell secretory response noted in previous studies.

Aging↗
PubMed1980

Papillary solute concentrations in acute ureteral obstruction. The effect of prostaglandin inhibition.

Complete unilateral and bilateral ureteral obstruction (24 hr) was produced in rats to evaluate the pathogenesis of the renal concentrating defect. Papillary solute concentration was significantly altered by both. The tissue osmolality of the papilla of the obstructed kidney was depressed to 50% of that found in an unobstructed kidney as a result of a marked reduction in tissue sodium and urea concentrations. No effects on tissue potassium concentration were observed. The administration of indomethacin and meclofenamate did not prevent the derangement in tissue solute concentration produced by obstruction. We conclude that prostaglandins do not seem to contribute to the concentrating defect produced by ureteral obstructions.

Acute Disease↗
PubMed1978

Bile acids in tissues: binding of lithocholic acid to protein.

Human liver contains two forms of lithocholic acid. One form is readily extractable by 95% ethanol/0.1% ammonia (soluble lithocholate, SL), while the other remains firmly bound to the residue (tissue-bound lithocholate, TBL). TBL could be hydrolytically released using clostridial cholanoylamino acid hydrolase, suggesting a peptide link between lithocholate and protein. With bovine serum albumin (BSA), lithocholic acid showed spontaneous amino group-modifying activity. When small molecular weight lysine (alpha-t-BOC-1-lysyl-beta-naphthylamide) and arginine peptides (alpha-CBZ-di-arginyl-beta-naphthylamide) were used in place of BSA, lithocholate bound specifically to the lysine peptide. The unusual affinity for lysine suggested that this amino acid might be involved as a residue in TBL. Synthesis of lithocholyl lysines and comparison with products of acid hydrolysis of TBL established epsilon-lithocholyl lysine as the predominant form in which lithocholic acid is found in tissue bound form.

Amino Acids↗
PubMed1977

Ouabain inhibition of gill Na-K-ATPase: relationship to active chloride transport.

Ouabain circulating in blood inhibits Na-K-ATPase in the gills of seawater eels at a concentration similar to that necessary for inhibition in vitro. By contrast, a much higher concentration is required when ouabain is applied to the exterior of the gill. Inhibition by external ouabain occurs only when the drug gains access to the circulation of the fish, as evidenced by simultaneous inhibition of Na-K-ATPase in the kidney. These results suggest that the Na-K-ATPase of gill chloride cells faces inward, lining intracytoplasmic tubular channels continuous with the extracellular fluid. Inhibition of gill Na-K-ATPase by ouabain in intact salt water eels results in almost complete inhibition of the efflux of both Na+ and Cl-. The efflux is tritiated water was much less reduced, to 60% of normal. Since chloride is actively transported outward across the gill of seawater teleosts, it is suggested that active chloride transport is coupled to Na-K-ATPase. A neutral sodium chloride carrier is postulated that is energized by the movement of sodium from extracellular fluid down its electrochemical gradient into the chloride cell.

Adenosine Triphosphatases↗
PubMed1977

Pharmacokinetics of mercaptopurine.

The anatomical distribution of mercaptopurine was investigated in rats at dose levels of 2.5 and 25 mg/kg iv. The plasma and tissues were analyzed by radioisotopic dilution and spectrofluorometric techniques. The tissue-plasma ratios were: liver-plasma, approximately 4.0; kidney-plasma, approximately 2.4; spleen-plasma, approximately 1.7; muscle-plasma, approximately 1.4; gut lumen-plasma, approximately 3; and bone marrow-plasma, approximately 0.35. Physiologically based pharmacokinetic models were developed to simulate concentrations of mercaptopurine in plasma, kidneys, liver, muscle, spleen, bone marrow, and gut lumen. The agreement between experimental and predicted plasma and tissue profiles was good. Human plasma levels of mercapto-purine were predicted and, when compared with clinical data, demonstrated reasonable agreement.

Animals↗
PubMed1977

Roles and expectations for mental health professionals in law enforcement agencies.

To assess consumer needs for and attitudes toward mental health services within law enforcement agencies, a questionnaire composed of a comprehensive list of mental health services potentially available to police departments was administered to populations of police officers and mental health workers. Respondents rated the services according to perceived utility of the service for law enforcement needs. Generally, police officers seemed receptive to several kinds of mental health service, although they were less enthusiastic about the value of the services than professionals. The implication of these data for the community mental health worker are discussed in terms of establishing and maintaining effective, mutually satisfying relationships with law enforcement agencies.

Attitude↗
PubMed1976

The training of paraprofessionals as behavior modifiers: a review.

Paraprofessionals are increasingly being employed in the mental health field. While much interest has focused on their roles and functioning, little systematic attention has been devoted to an examination of training practices. Because a particularly compatible relationship may exist between paraprofessionals and the behavioral model of intervention, this review focuses on the training and use of paraprofessionals as behavior modifiers. Paraprofessional populations reviewed include psychiatric aides and nurses, college students, inpatients, and community and indigenous workers. The review concludes that a strong case can be made for the administrative feasibility of training and utilizing diverse groups of paraprofessionals as behavior modifiers. The lack of consistent, solid outcome evidence prohibits a conclusion relative to the effectiveness of these paraprofessionals at this point in time. Numerous researchable questions concerning the effectiveness of various forms of training with paraprofessionals, optimal length of training for various purposes, training resistances, etc., are unanswered. Beyond this, a serious lack of communication of the basic process of training is revealed, and the perhpas questionable roles paraprofessionals are being trained for is discussed.

Allied Health Personnel↗