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Biomedical subjects

S Paul

Publications and source records attributed to S Paul.

At least 253 records · Page 14Linked to original sources
PubMed1989

Prognostic factors in the surgical treatment of azoospermia.

Surgery for male obstructive infertility is not always successful. A number of clinical and operative findings, not previously reported, may influence the outcome. We have studied 182 patients with azoospermia who underwent vasoepididymostomy. The pre-operative and operative findings which adversely affected the function of the anastomosis were identified. The presence of spermatozoa in the semen sample was taken to mean a successful anastomosis. Abnormal testicular histology was an adverse pre-operative finding. Adverse operative findings included non-canalisation of the epididymal tubules and hypoplasia of the epididymis; both factors were associated with a high failure rate (almost 100%). The anastomosis was a failure in 78% of the patients when no fluid was seen on sectioning the epididymis. In the absence of adverse findings the success rate of vasoepididymostomy was 59%. Pre-operative testicular biopsy, together with careful observation and recording of findings before and during surgery, are recommended to avoid needless exploration and anastomosis.

Adult↗
PubMed1989

[Virulence factors of animal pathogenic Salmonellae with reference to plasmid typing].

All the representatives of the genus Salmonella belong to one pathogenic species S. enterica. The virulence intensification of Salmonella are due mainly to endo-, entero- and cytotoxins, fimbria, cilia, the invasion capacity and the serum resistance. The plasmid code is among a series of virulence factors. Studies about the plasmid profile of the salmonella strains is of great importance to the characterisation of the isolates from the epidemiological point of view as well as for research purposes.

Animals↗
PubMed1989

Caffeine potentiates the renin response to furosemide in rats. Evidence for a regulatory role of endogenous adenosine.

Adenosine is a potent inhibitor of renin release. It has therefore been suggested that endogenous adenosine may play a role in the regulation of renin release. Sodium-chloride transport at the level of the macula densa has been proposed as the primary source of endogenous adenosine. Evidence to support a modulatory role of adenosine on renin release in vivo is, however, limited. We therefore wanted to determine if: 1) adenosine modulates furosemide-induced renin release and 2) sodium-chloride reabsorption at the macula densa is essential for adenosine actions. To test these hypotheses, three groups of rats were pretreated either with saline or the adenosine receptor antagonists caffeine or 1,3-dipropyl-8-(p-sulfophenyl)xanthine (both at a dose of 30 mg/kg followed by 450 micrograms/kg/min). Rats then received furosemide (50 mg/kg i.v.). In the vehicle group, furosemide increased urinary volume, sodium and potassium excretion and increased plasma renin activity from 6 +/- 1 to 45 +/- 11 ngAl/ml/hr. Caffeine and 1,3-dipropyl-8-(p-sulfophenyl)xanthine potentiated the increase in plasma renin activity produced by furosemide (to 120 +/- 15 and 147 +/- 21 ng Al/ml/hr, respectively), whereas having no significant effects on urinary volume, sodium excretion or blood pressure. These results suggest that furosemide-induced renin release in vivo is restrained by endogenous adenosine. In as much as furosemide blocks sodium-chloride transport in the thick ascending limb of Henle's loop and the macula densa cells, it appears that under the conditions of this study sodium transport across these segments is not essential to initiate adenosine-mediated mechanisms.

Adenosine↗
PubMed1988

Receptor binding of guinea pig and pig vasoactive intestinal peptides by rat lung.

Guinea pig vasoactive intestinal peptide (gpVIP) differs from other mammalian VIPs in four of its 28 amino acid residues. In the present study, the gpVIP displaced 125I-labelled pig VIP (pVIP) binding by rat lung membranes with 7.7-fold lower potency than pVIP. Degradation of gpVIP by rat lung membranes, assessed by radioimmunoassay and h.p.l.c., was 1.9-fold greater than that of pVIP. This difference in degradation of the two peptides was not large enough to account for the lower receptor-binding potency of gpVIP. The amino acid residues that distinguish pVIP from gpVIP are likely to contribute to the interaction of VIP with receptors and peptide hydrolases in lung membranes.

Animals↗
PubMed1988

Surgical unit time utilization review: resource utilization and management implications.

As health care providers seek ways to reduce the cost of health care services, hospital operating rooms (ORs) have been identified as potential areas for cost reduction efforts. Cost containment efforts which have shifted significant portions of the inpatient population to ambulatory areas have resulted in an inpatient population which is sicker and more procedure-intensive. Efficient management of operating rooms has assumed even greater importance in this environment. Inefficient or inaccurate scheduling of OR time often results in delays of surgery or cancellations of procedures, which are costly to the patient and the hospital. Approaches to efficient use of ORs include computerized scheduling, utilization monitoring, and refinement of scheduling policies and procedures. In the absence of commercially available software to meet operating room management information needs, Johns Hopkins developed its own system in 1983. This software provides detailed information for daily OR management and long-term planning. The computerized operating room scheduling and monitoring system is described in this article and an operational measure of scheduling accuracy is proposed. Suggestions are made for incorporating this measure into planning and allocation decisions.

Appointments and Schedules↗
PubMed1988

Human autoantibody to vasoactive intestinal peptide: increased incidence in muscular exercise.

Specific autoantibodies to vasoactive intestinal peptide were present in plasma from 29.6% healthy human subjects who habitually performed muscular exercise, compared to 2.3% healthy subjects who did not. Saturation analysis of VIP binding by the plasmas suggested the presence of 1 and 2 classes of autoantibodies in 5 and 3 high exercise subjects, respectively, distinguished by their equilibrium affinity constants (Ka). The mean Ka values for the high and low affinity autoantibody classes were, respectively, 1.3 x 10(8) M-1 and 0.8 x 10(7) M-1. These values are lower than the Ka range reported previously for tissue VIP receptors (G. Rosselin. Peptides 7, Suppl. 1, 89, 1986) but are larger than the inverse Michaelis constant (1/Km) for VIP-degrading proteases (T.N. Keltz, E. Straus, R.S. Yalow. Biochem. Biophys. Res. Commun. 92, 669, 1980). The autoantibodies may not interfere with VIP-receptor binding but are potential inhibitors of the proteolytic inactivation of VIP.

Adult↗
PubMed1988

A simple liquid-chromatographic method applied to determine caffeine in plasma and tissues.

In this simple, reliable assay for quantifying caffeine in plasma and tissues, methylxanthines are first partly purified from plasma and acid extracts of tissue by passage through solid-phase columns. The ease of this extraction method permits a relatively large number of samples to be processed daily. Quantification is by reversed-phase high-pressure liquid chromatography (mobile phase: acetic acid/acetonitrile/water, 2/6/92 by vol). Caffeine is eluted in 20 min. The reliability of this method allows its automation. This method has been adapted to measure caffeine in brain and kidney extracts and in as little as 10 microL of plasma. After 10 days of oral administration of caffeine (1 g/L, in drinking water) to six rats, the mean (+/- SEM) concentrations of caffeine in plasma, brain, and kidney were 18.6 +/- 6.0 micrograms/mL, 16.2 +/- 1.5 micrograms/g, and 18.9 +/- 2.0 micrograms/g, respectively. Correlations were linear between concentrations of caffeine in plasma and brain (r = 0.86) and between concentrations in plasma and kidney (r = 0.91). This method should be useful in studying the effects and mechanisms of actions of methylxanthines.

Animals↗
PubMed1988

Self-care behaviors and informational needs of seropositive homosexual/bisexual men.

Patients with acquired immune deficiency syndrome (AIDS) or AIDS-related complex (ARC) are developing beliefs, behaviors, and a knowledge bases that may affect their health status, sense of well-being, and health care needs. However, little documentation of these changes exists. Consequently, the purpose of this study was to describe AIDS beliefs, behaviors, and informational needs of homosexual/bisexual human immunodeficiency virus (HIV) seropositive patients 7 years into the epidemic. Data were collected once from 178 patients using a modified version of the AIDS Beliefs and Behaviors Questionnaire (ABBQ). Study results showed that in 1987, most outpatients (73%) in an AIDS epicenter wanted more information about building their immune systems. Few patients (12%) wanted more explicit information about safe sexual behaviors, although 3 years into the epidemic this information was a central concern. Results suggest that health professionals need to take an active role in monitoring and addressing patients' changing informational needs.

AIDS-Related Complex↗
PubMed1987

High affinity peptide histidine isoleucine-preferring receptors in rat liver.

Peptide Histidine Isoleucine (PHI) is generally considered a low affinity agonist for Vasoactive Intestinal Peptide (VIP) receptors. In this study, we investigated the presence and characteristics of [125I]PHI binding sites on rat liver membranes. Detergents at nonsolubilizing concentrations (1 mM CHAPS or 0.01% Tween-20) were included in the assay buffer to reduce adsorptive loss of PHI to acceptable levels and permit measurement of PHI-binding to receptors. Under these conditions, binding of PHI to liver membranes was time- and temperature-dependent, reversible and saturable. Unlabeled PHI was 9.7-fold more potent than VIP, and 357-fold more potent than secretin in displacing [125I]-PHI binding. Scatchard analysis suggested the presence of two classes of PHI receptors, with Kd 27 pM and 512 pM. The data from [125I]-PHI and [125I]-VIP binding studies suggested that one class of receptors was PHI-preferring, and the other, equally reactive with PHI and VIP. The concentration of immunoreactive PHI, measured by radioimmunoassay, in blood from the hepatic portal vein of anesthetized rats was 2-fold higher than that from the hepatic vein, suggesting uptake of circulating PHI by the liver.

Animals↗
PubMed1987

Characterization of receptors for vasoactive intestinal peptide solubilized from the lung.

The zwitterionic detergent CHAPS was used to solubilize functional receptors for vasoactive intestinal peptide (VIP) from guinea pig lung. The solubilized receptors were resolved by high performance gel filtration in 3 mM CHAPS into two active fractions with apparent Stokes radii of 5.9 +/- 0.1 and 2.3 +/- 0.1 nm. The binding of 125I-VIP to the two receptor fractions was time-dependent, reversible, and saturable. Trypsin destroyed the binding activity of the receptor fractions, indicating their proteinic nature. Unlabeled VIP competitively displaced the binding of 125I-VIP to the 5.9-nm fraction (IC50 = 240 pM) and the 2.3-nm fraction (IC50 = 1.2 microM). Scatchard analysis indicated a single class of binding sites in each receptor fraction, with Kd values 300 pM and 0.97 microM for the 5.9- and 2.3-nm Stokes radii fractions, respectively. When the high affinity, 5.9-nm Stokes radius fraction was rechromatographed in 9 nM CHAPS, 46% of the binding activity eluted in the low affinity, 2.3-nm Stokes radius fraction, indicating that the latter is a product of dissociation of the high affinity receptor complex. GTP inhibited the binding of 125I-VIP to the high affinity complex but not the low affinity species. Scatchard plots of VIP binding by the high affinity receptors treated with GTP suggested the presence of two distinct binding sites (Kd 4.4 and 153 nM), compared to a single binding site (Kd = 0.3 nM) obtained in untreated receptors. The nonhydrolyzable GTP analog, guanyl-5'-yl-imidodiphosphate, inhibited VIP binding by the high affinity receptor fraction with potency nearly equivalent to that of GTP. These observations suggest that GTP-binding regulatory proteins are functionally coupled to the VIP-binding subunit in the high affinity receptor complex. The peptide specificity characteristics of the two receptor fractions were different. Peptide histidine isoleucine and growth hormone releasing factor, peptides homologous to VIP, were 87.5- and 22.9-fold less potent than VIP in displacing 125I-VIP binding by the high affinity receptor complex, respectively. On the other hand, growth hormone-releasing factor was more potent (22.7-fold) and peptide histidine isoleucine was less potent (31.3-fold) than VIP in displacing the binding by the low affinity species.

Animals↗
PubMed1987

Environmentally-induced modification of the benzodiazepine/GABA receptor coupled chloride ionophore.

The benzodiazepine/GABA receptor coupled chloride ionophore was examined in brain membranes of rats maintained in either a conventional animal facility or a "protected" (low-stress) environment. Following a 10 min ambient temperature swim, animals maintained in both environments had qualitatively similar increases in the number (Bmax) of [35S]t-butylbicyclophosphorothionate (TBPS) binding sites, the apparent affinity of this radioligand, and the efficacy and potency of Cl- to enhance [3H]flunitrazepam binding. Nonetheless, the Bmax of [35S]TBPS and efficacy of Cl- to enhance [3H]flunitrazepam binding were significantly lower in animals housed in the protected environment compared to those maintained in a conventional facility both before and after swim stress. Furthermore, in rats housed in a protected environment, sequential removal of animals from a common cage (cohort removal), produced a very rapid increase (less than or equal to 15 s) in Cl(-)-enhanced [3H]flunitrazepam binding in cortical and hippocampal but not cerebellar membranes. Cohort removal also produced a sequential increase in the number of [35S]TBPS binding sites and apparent affinity of this radioligand in cerebral cortical membranes. The effects of cohort removal were not observed in animals subjected to ambient temperature swim or if animals were removed from different cages. Changes in the benzodiazepine/GABA receptor coupled chloride ionophore produced by cohort removal from a common cage preceded any statistically significant changes in circulating levels of alpha-MSH, beta-endorphin, ACTH or corticosterone. These findings suggest that the benzodiazepine/GABA receptor chloride ionophore complex (supramolecular complex) is under both tonic and acute regulation by the environment, and may subserve a physiologically relevant function in the response to stressful or anxiety producing stimuli.

Animals↗
PubMed1987

CSF corticotropin-releasing hormone in depressed patients and normal control subjects.

The authors studied CSF corticotropin-releasing hormone (CRH) and plasma cortisol in 22 depressed patients and 18 normal control subjects. CRH levels were similar in the two groups. Depressed patients who were nonsuppressors on the dexamethasone suppression test had significantly higher levels of CRH than suppressors did. The depressed patients' CRH levels were significantly correlated with 4:00 p.m. postdexamethasone plasma cortisol levels. While the inclusion of a depressed patient with an outlier CRH value resulted in the loss of statistical significance for both of these findings, the authors suggest that these results support the hypothesis that hypercortisolism in depressed patients in part reflects a defect at or above the hypothalamus, resulting in hypersecretion of CRH.

Adult↗