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Biomedical subjects

S Solomon

Publications and source records attributed to S Solomon.

At least 307 records · Page 17Linked to original sources
PubMed1980

In situ micropuncture study of pancreatic duct pH.

The pH and chloride concentration in the extralobular duct system of the rabbit pancreas was investigated by using glass-membrane pH microelectrodes and microsampling techniques. The response of pH microelectrodes was compared to that of a pH macroelectrode system in buffer solutions containing common interfering substances and it was found that the electrodes were insensitive to these substances. Final pancreatic juice electrolyte concentrations and osmolality were found to be similar to that observed by others. Under free-flow conditions, a significant pH gradient was found between small extralobular ducts (7.47) and final juice (8.03). This gradient was nearly obliterated on stimulation with secretin. Duct chloride concentrations were found to be similar in all duct sizes and final juice under unstimulated conditions and after stimulation with secretin. It is concluded that glass-membrane pH microelectrodes are reliable and accurate indicators of pH in this system. The present experiments suggest that the entire extralobular ductal system may participate in the secretion of an alkaline fluid.

Animals↗
PubMed1980

Effects of prostaglandins on the adenylate cyclase activity of lungs from fetal rabbits.

Prostaglandin E1 (PGE1) and PGI2 stimulate adenylate cyclase activity in lungs from fetal rabbits (29 days of gestation) with EC50 values of 4.4 and 2.6 X 10(-7) M, respectively. PGE2, PGD2, PGF2 alpha, and 6-oxoPGF1 alpha are active only at much higher concentrations. The response of adenylate cyclase to PGE1 rises gradually from 16% to 60% above basal between days 21-26 of gestation. Between days 26-27 of gestation, there is a sharp increase in stimulated activity to 120% above basal (P < 0.001). This level is maintained until 3 days after birth. A further increase was observed 8 days after birth. Stimulation of adenylate cyclase by fluoride increases gradually from about 100% to nearly 400% above basal activity between 21 days of gestation and 8 days after birth. During this time there are no significant changes in basal activity. The increased response of adenylate cyclase to PGE1 between days 26-27 of gestation occurs at a time when unbound plasma cortisol and synthesis of pulmonary surfactant start to increase in the fetal rabbit. It is possible that cortisol sensitizes adenylate cyclase to prostaglandins, which could explain some of the its actions on surfactant synthesis.

Adenylyl Cyclases↗
PubMed1980

Placental hormones, nutrition, and fetal development.

Fetal growth retardation due to maternal malnutrition is widespread especially in the Third World. Little is known about the mechanisms that regulate the growth of the fetus and placenta during protein malnutrition. It is known that the placental size and levels of circulating placental hormones such as human chorionic gonadotrophins (hCG), human placental lactogen (hPL), and estrogens are affected by the nutritional status of the mother. There is suggestive evidence that during malnutrition, hPL may increase lipolysis and exert a glucose sparing effect in the mother, thereby promoting glucose availability to the fetus. We have studied the influence of dietary protein deficiency on the binding of dexamethasone to the specific cytosol receptors in adult and fetal tissues. A low protein diet in adult male rats is associated with a decrease in dexamethasone binding to liver cytosol receptors. On the other hand, protein deprivation in pregnant female rats leads to an increase in dexamethasone binding to liver cytosol receptors of both the mother and fetus. However, the influences of maternal protein deprivation on dexamethasone receptors in the fetal liver and lungs are not similar. At 21 days gestation the binding of dexamethasone to fetal lung receptors of protein-deficient mothers is lower than that in the controls. These differences at a critical time in the fetal lung development indicate that a fall in receptors for dexamethasone may lead to impaired phospholipid synthesis in fetuses of protein-deficient mothers and point to the importance of nutritional factors in the biochemistry of fetal development.

Animals↗
PubMed1979

How one hospital broke its inflation fever.

The Johns Hopkins Hospital has demonstrated that hospital costs can be decreased without governmental intervention (controls). From 1975 to 1978, the hospital inflation rate was cut by half. One key factor, according to Solomon, was a move to decentralize management which was accompanied by a detailed system for monitoring costs. Also instrumental were administration's consistent reminders to physicians and managers about keeping costs down. The hospital was reorganized from a system of clinical departments that behaved, says Solomon, like "fiefdoms" into 14 autonomous departments that function under their own budgets. Each department controls about 85% of its costs (up from 30%), and is set up to function "like a small business." A breakdown of where cost reductions took place shows a savings of $5 million in overhead and $1.5 million in malpractice claims (Hopkins self-insured). Individual departments have also achieved some dramatic reductions: the Department of Medicine decreased the number of laboratory tests ordered; and the Department of Gynecology and Obstetrics built a new facility with fewer beds than the old one.

Cost Control↗
PubMed1979

Exocrine ductal pCO2 in the rabbit pancreas.

An improved pCO2 microelectrode has been evaluated and used to investigate whether a significant barrier to diffusion of CO2 exists in the rabbit pancreas. The results of this study show the improved Carter and Caflisch pCO2 microelectrode to be an accurate and reliable tool for measuring pancreatic venous and ductal pCO2. The similarities between pCO2 values from the pancreatic ducts and small pancreatic veins suggest that there is no barrier to CO2 diffusion between small veins and exocrine ducts in the rabbit pancreas, and that ductal pCO2 is probably strongly influenced by the CO2 tension of the small pancreatic blood vessels.

Animals↗
PubMed1979

Effects of paced respiration and expectations on physiological and psychological responses to threat.

While waiting to receive electric shocks, 105 males either (a) regulated their breathing at one half the normal rate, (b) regulated their breathing at the normal rate, or (c) did not regulate their breathing rate. Half of the subjects in each breathing condition were told that their breathing task would aid them in relaxing, whereas the other half were not given that expectation. Subjects in a no threat condition were not threatened with shocks, did not regulate their breathing, and were not provided with expectations. The results indicated that slowing respiration rate reduced physiological arousal as measured by skin resistance and finger pulse volume (but not heart rate) and reduced self-reports of anxiety. Expectations did not influence arousal. These data provide evidence for the effectiveness of paced respiration as a coping strategy, and they resolve the conflicting findings of previous investigations.

Adult↗
PubMed1979

Congenital complete heart block in the newborn associated with maternal systemic lupus erythematosus and other connective tissue disorders.

Four babies with complete heart block associated with maternal systemic lupus erythematosus (SLE) are described, together with a 5th baby whose mother had serological abnormalities only. One baby had a rapidly fatal outcome, one has required digoxin for heart failure, and the remaining 3 are asymptomatic but remain in complete heart block. Additional manifestations were present in 2 of them. The spectrum of neonatal abnormalities that may occur in association with maternal SLE and related connective tissue disorders is discussed, together with the possible causes and the prognosis. We conclude that congenital heart block is more common than had previously been appreciated.

Adult↗
PubMed1979

Renal response to Ringer expansion in developing rats.

Male rats were studied between 20 and 60 days of age. Standard renal clearance techniques were used. The efficiency of the diuretic response, the sodium response, and the potassium response were calculated as defined previously. Results indicate that both diuretic and sodium efficiency is lower between the ages of 20 and 30 days as compared to 40 and 60 days of age, whereas potassium efficiency shows no age dependence. In morphological studies, it has been observed that the proximal tubule cells of 22-day-old rats show changes in lateral intercellular spaces with comparable features to those of mature animals. The spaces widened during volume expansion. The change is quantitatively the same as that found in mature rats. Both blood pressure and hematocrit show continuous increase with age. The response of Ringer infusion in both immature and mature animals may be a mixed response involving changes in physical factors and renal responses to volume expansion per se.

Age Factors↗
PubMed1979

Evidence that the renal response to volume expansion involves a blood-borne factor.

The effect of blood volume expansion in immature rats by blood from infants (J to J expansion) and mature animals (A to J) has been studied. A to J expansion results in an increased renal response to expansion which is greater than J to J, but not as great as when mature animals are expanded with blood from other matures (A to A) or pooled blood from infants (J to A). A to A and J to A expansions show no significant differences in renal responsiveness. The lack of an immature response is not due to differences in animal hydration since 2.5% volume expansion is on the flat part of dose response curve. Part of the scatter of the adult response is related to absolute levels of GFR which might indicate the existence of a filterable natriuretic factor or, alternatively, a dependence of renal responsiveness on filtered load. These results are interpreted to indicate that mature rats contain a natriuretic factor or an inhibitor of an antinatriuretic factor which is blood borne and is probably secreted in blood volume expanded rats.

Age Factors↗
PubMed1979

Antigenic subtypes of HBsAg: their distribution and pattern of occurence among blood donors and patients with liver diseases and leprosy in Tamilnadu, India.

One hundred and seventy hepatitis B Surface antigen positive sera derived from blood donors, patients with liver diseases and leprosy were antigenically subtyped by Rheophoresis and 107 of them by agar-gel diffusion. For the first time in India HBsAg/adr as a predominant subtype (64.0%) is documented. Of the two methods adopted, Rheophoresis showed a greater sensitivity of typing, namely 82.3% in contrast to 39.2% only by agar-gel diffusion (p less than 0.001). Analysis of the Hepatitis Be antigen and antibody (anti HBe) positive sera for subtype predeliction revealed the same pattern as in HBe system negative sera.

Blood Donors↗
PubMed1978

Formation of 20-hydroxyprostaglandins by lungs of pregnant rabbits.

Homogenates or particulate fractions (1,000 to 100,000 X g) from lungs of pregnant rabbits were incubated with prostaglandins or prostaglandin metabolites and the products were purified by chromatography and identified by gas chromatography-mass spectrometry. In the presence of NADPH, particulate fractions from pregnant rabbit lungs converted prostaglandins E1, E2, and F2alpha as well as 13,14-dihydro-15-oxoprostaglandin E2 and 13, 14-dihydro-15-oxoprostaglandin F2alpha to their 20-hydroxy derivatives. In the cases of the 3 primary prostaglandins, the corresponding omega-carboxylic acids were also isolated. The omega-hydroxylation reaction occurred in the presence of the microsomal fraction. The mitochondrial fraction was much less active whereas the cytosol fraction converted prostaglandins to their 13, 14-dihydro-15-oxo derivatives. When prostaglandin F2alpha was incubated with homogenates of lungs from pregnant rabbits, omega-oxidation was combined with oxidation of the 15-hydroxyl group and reduction of the 13, 14-double bond to give 13, 14-dihydro-20-hydroxy-15-oxoprostaglandin F2alpha as well as the corresponding derivative with an omega-carboxylic acid group. Lungs from nonpregnant rabbits were much less active than lungs from pregnant rabbits in the omega-oxidation of prostaglandins.

Animals↗