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Biomedical subjects

W Bishop

Publications and source records attributed to W Bishop.

At least 19 recordsLinked to original sources
PubMed1996

Acute effects of digitalis and enalapril on the neurohormonal profile of chagasic patients with severe congestive heart failure.

Chagasic patients with congestive heart failure are usually treated with digitalis and converting enzyme inhibitors. According to the neurogenic and dysautonomic theories, chagasic patients would not benefit from these drugs. To clarify this controversial issue, we have studied patients with congestive heart failure and suspected Chagas' heart disease. All patients received intravenous methyl-digoxin for 24 h and oral enalapril for 96 h. Blood samples for plasma norepinephrine, aldosterone and renin were taken at baseline, after acute digitalization and following enalapril. Based on the serology for Chagas' disease, the patients were divided into non-chagasic and chagasic patients. In the chagasic group three patients were in functional class III and 3 were in functional class IV. In the non-chagasic group five patients were in functional class III and 2 were in functional class IV. Both groups had a marked and quantitatively similar degree of neurohormonal activation. All patients improved at least one functional class and lost more than 5 kg of body weight with treatment. The chagasic patients had a statistically significant reduction in plasma norepinephrine (2262 +/- 1407 to 865 +/- 390, P < 0.008, pg/ml, M +/- S.D.), plasma aldosterone (330 +/- 168 to 155 +/- 75, P < 0.01, pg/ml, M +/- S.D.) and plasma renin activity (14 +/- 13 to 2 +/- 1.6 ng/ml per h, M +/- S.D., P < 0.05), with digitalis. Following enalapril, norepinephrine and aldosterone there was a further but non-significant reduction, when compared to postdigitalis values. These results indicated that chagasic patients do benefit from digitalis and enalapril. Furthermore, the prominent and significant reduction in all three neurohormones suggest that the parasympathetic and sympathetic systems of these chagasic and non-chagasic patients, are responding to the neuromodulatory effects of digitalis and enalapril.

Aldosterone↗
PubMed1996

Cytokines regulate apolipoprotein B secretion by Caco-2 cells: differential effects of IL-6 and TGF-beta 1.

A variety of cytokines are found in the intestinal mucosa of individuals with inflammatory diseases. The potential role of cytokines in mediating lipoprotein assembly and secretion in the human intestinal cell line, Caco-2, was investigated. Interleukin-1 beta, interleukin-6 (IL-6), and tumor necrosis factor-alpha all decreased the basolateral secretion of apolipoprotein B (apo B), with IL-6 being the most potent. IL-6 was also found to inhibit triacylglycerol secretion. In contrast, transforming growth factor-beta 1 (TGF-beta 1) increased the secretion of apo B and triacylglycerol. In pulse-chase experiments, IL-6 decreased the rate of synthesis and secretion of apo B-100 and apo B-48 without altering the rate of apo B degradation, whereas TGF-beta 1 increased the rate of synthesis and secretion of apo B-100 and apo B-48. Degradation of apo B was also not affected by TGF-beta 1. The abundance of apo B mRNA in cells incubated with IL-6 was decreased, whereas cells incubated with TGF-beta 1 had higher levels of apo B mRNA. In conditions of small intestinal inflammation, cytokines could contribute to the observed malabsorption of fat and other nutrients by the small intestine.

Animals↗
PubMed1996

[Leydig cell function in hyper- or hypoprolactinemic states in healthy men].

In the present investigation the function of the Leydig cells, as the response of gonadal steroids to the injections i.m. of 2000 UI of hCG, was studied in 11 normal men, before and after the induction of hyper or hypoprolactinemia with sulpiride and bromocriptine treatments respectively. The normal response to hCG, showed an increment of serum estradiol concentration 24 h and another of serum testosterone 72 h after the administration of the gonadotropin. The serum FSH concentration decreased during the test. An increase of serum LH levels was observed in the hypoprolactinemic state, but the increment of estradiol was lower after injection of hCG. On the other hand, the hyperprolactinemia induced a low basal level of testosterone with a higher response of this steroid to hCG. The results suggest that hyperprolactinemia interfers the estradiol synthesis by Leydig cells while the loss of the trophic effect of prolactin on gonadal steroidogenesis, as seen in hypoprolactinemia produces a decrease of basal testosterone levels without any alteration of the response of this steroid to hCG. We conclude that prolactin plays an important role in the steroidogenesis of Leydig cells in normal men.

Adult↗
PubMed1992

[In vitro stimulation of Leydig cells with human chorionic gonadotropin in adult rats of different ages].

We studied the functional reserve of Leydig cells in adult rats of different ages in vitro. Suspensions of Leydig cells after digestion by collagenase were stimulated with Human Chorionic Gonadotropin (hCG) during different times (1, 3 and 5 hours). We observed that response of Leydig cells, expressed by the testosterone concentration in the culture medium, showed a similar pattern in all studied group, and the highest response was seen at three hours of incubation. On the other hand, the testosterone response to hCG varied with age of animal. Thus, it was higher in the group of 14 months old (middle aged) than young animals (5 month old) and decreased in old animals (21 months old). These results suggest that a primary testicular lesion occurs with aging.

Age Factors↗
PubMed1985

Attempts to isolate N-nitroso compounds from Chinese-style salted fish.

Various types of salted fish have been collected from Hong Kong and analyzed for volatile nitrosamines and bacterial mutagenicity. Both of these parameters were low in the samples as collected. Exposure of these samples to nitrite yields substantial quantities of nitrosamines and mutagenic activity.

Animals↗
PubMed1984

Inhibition of in vitro human chorionic gonadotropin-stimulated testosterone production in testis and of ovulation in the rat by charcoal-treated rat testicular extract.

Previously, we described the presence of a factor obtained from a 105,000 X g supernatant of rat testis that was found to inhibit human chorionic gonadotropin (hCG) binding to gonadal receptors. In the present study, similarly prepared testicular extract was tested for its effects on in vitro hCG-stimulated testosterone production by isolated testis interstitial cells and for its effect on spontaneous ovulation in the rat. Incubation of interstitial cells with charcoal-treated extract significantly inhibited the steroidogenic response to hCG in a dose-related manner. This inhibition was also apparent after heating the extract for 10 min at 100 degrees C. Preincubation of the cells with charcoal-treated extract resulted in an inhibitory effect that was not readily reversed by subsequent addition of hCG, revealing an element of irreversibility in the mechanism of inhibition. A single i.p. injection of testicular extract given between 1430-1630 h of proestrus inhibited spontaneous ovulation in the rat. This effect was also observed after heating the extract for 10 min at 100 degrees C; in contrast, no significant effect was obtained with the injection of a similar dose of liver extract. Administration of 5 IU hCG after pretreatment with the testicular extract did not reverse the inhibitory effect on ovulation, indicating that this effect was probably not exerted at the hypothalamus-pituitary level. It is concluded that the aqueous testicular extract contains a factor able to antagonize the physiological events mediated by luteinizing hormone (LH)/hCG, and that this factor is consistent with the presence of an LH/hCG-binding inhibitory activity in rat testis.

Animals↗
PubMed1983

Plasma bupivacaine concentrations in children during caudal epidural analgesia.

Plasma bupivacaine concentrations were measured in 45 children, whose ages ranged from 4 months to 12 years, following administration of caudal epidural analgesia. Using 3 mg/kg of bupivacaine 0.25%, mean blood levels of 1.2-1.4 microgram/ml were reached, which are well within the limits of projected toxic levels. Simultaneous arterial and venous sampling showed a small but significant difference between these two sampling sites fo the first fifteen minutes.

Age Factors↗
PubMed1983

Plasma lignocaine concentrations following topical laryngeal application.

Lignocaine 4%, 4 mg/kg, was sprayed onto the larynx and subglottic area of 96 children aged from 2 weeks to 12 years and plasma lignocaine concentrations were measured. While the majority were well within the accepted safe range (4.5 micrograms/ml) occasional concentrations over 8 micrograms/ml appeared in all groups. Simultaneous arterial and venous sampling showed a small but significant difference in the first 10 minutes.

Administration, Topical↗