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Biomedical subjects

Z Brown

Publications and source records attributed to Z Brown.

48 records · Page 3Linked to original sources
PubMed1983

Stress induced suppression of maintenance but not of acquisition of ethanol consumption in rats.

Male Wistar rats were given a free-choice between water and increasing concentrations of ethanol from 3% to 11% (v/v) during the acquisition phase. Thereafter, animals were maintained on a choice between water and 11% ethanol for the balance of the experiment. For 5 days prior to and for periods during the acquisition and maintenance phases, the animals were exposed to electric footshock, restraint or no stress. The results showed no differences in ethanol drinking patterns among the groups during the acquisition phase. However, in the maintenance phase, both footshock and restraint suppressed the increase in ethanol intake seen in the no-stress control group.

Alcohol Drinking↗
PubMed1983

First trimester serum zinc concentrations in human pregnancy.

Serum zinc concentrations in the 1st trimester of human pregnancy were evaluated in 106 women whose dates of conception were precisely determined by basal body temperature monitoring and human chorionic gonadotropin levels. Data are reported by intervals of postovulatory days. Sera were analyzed for zinc by atomic absorption spectrophotometry after acid digestion. Mean 1st trimester serum zinc concentrations, determined by 20-day increments from ovulation, were 0.97 +/- 0.22, 0.68 +/- 0.14, 0.77 +/- 0.18, and 0.70 +/- 0.15 micrograms/ml; differences between means were significant at p less than 0.005, less than 0.005, and less than 0.01, respectively. These differences could not be related to diet, supplement use, or hematocritic changes. No differences were apparent between diabetic and nondiabetic subjects. Of the 25 samples from women who aborted spontaneously, zinc concentration of seven were lower than interval means.

Abortion, Spontaneous↗
PubMed1983

Reversibility of the analgesic effect of meptazinol in volunteers.

A double-blind randomized placebo-controlled study was carried out in 8 healthy volunteers to determine whether the analgesic and other actions of meptazinol could be reversed by naloxone or hyoscine. Heart rate, blood pressure, respiratory rate, pupil diameter, forearm ischaemic exercise tolerance and dental pain threshold were measured before and up to 45 minutes after intramuscular meptazinol 100 mg or placebo, when 'reversal' was attempted with intravenous naloxone 2 mg, hyoscine 1.6 mg or placebo. Meptazinol caused mild pupillary constriction which is unlikely to be clinically significant. Forearm ischaemic exercise tolerance failed to show any analgesic effect of meptazinol. Measurement of dental pain threshold strongly suggested reversal of meptazinol analgesia by naloxone but not by hyoscine, but inter-subject variation in analgesic response was great and these results require confirmation in a group pre-selected for consistent response.

Adult↗
PubMed1982

Recurrent genital herpes simplex virus infection in pregnancy: infant outcome and frequency of asymptomatic recurrences.

Eighty pregnant patients with a history of recurrent genital herpes simplex virus (HSV) infection were followed up with frequent genital examinations and cultures for HSV during their pregnancies. Recurrences of genital HSV during pregnancy were documented in 67 patients. Ninety-six percent of these had external genital lesions noted at some time during their pregnancy. One hundred eighty-six (93%) of the 199 recurrences of the disease were associated with external genital lesions. Of 13 episodes of asymptomatic viral shedding documented in this patient population, six were from the vulva alone, five were from the cervix alone, and two were from both the vulva and the cervix. Of 11 episodes of cervical HSV shedding, seven were asymptomatic and four were associated with external symptomatic lesions. Despite frequent recurrences of genital HSV infection during pregnancy, all study patients were delivered at term, and although they had a high rate of delivery by cesarean section (32.5%), the outcome of their infants was good.

Adolescent↗
PubMed1982

Impaired lymphocyte transformation in minimal change nephropathy in remission.

A group of 37 patients with minimal change nephropathy (MCN) in remission for a mean period of 4.9 years (range 0.25-10) and on no current treatment were found to have a lymphocyte response to the mitogen Concanavalin A which was significantly lower than normal (P less than 0.001). This reduction in lymphocyte transformation was mainly due to the 24 patients who had received in addition to steroids a course of cyclophosphamide from 1 to 12 years (mean 6.7 years) previously (P less than 0.005 when compared t normal). Although the lymphocyte response of the remaining group of 13 patients who had not been treated with cyclophosphamide was not significantly lower than normal, there were three whose lymphocyte response to Concanavalin A was below the normal range. Our findings indicate that remission of MCN may be accompanied by a persistence of the abnormal lymphocyte function which is present during the nephrotic phase, and that cyclophosphamide may cause or add to this defect by a long-term effect on lymphocytes.

Adolescent↗
PubMed1981

Long-term impairment of suppressor-cell function by cyclophosphamide in minimal-change nephropathy and its association with therapeutic response.

Lymphocyte suppressor-cell function was studied by induction with concanavalin A in 31 patients with minimal-change nephropathy (MCN) in remission. 21 patients had been treated with cyclophosphamide 0.5--12.0 years previously (mean 6.5 years) and had been in remission for 0.5--9.0 years (mean 5.1 years). The remaining 10 patients had never received cyclophosphamide and had been in remission for 1--10 years (mean 5.3 years). The cyclophosphamide-treated group had significantly less suppressor-cell function than either the controls or the non-cyclophosphamide-treated group, the latter being not significantly different from normal. When patients who had received cyclophosphamide were divided into those who had relapsed after taking this drug (10 patients) and those who had not (11 patients), suppressor-cell function was significantly impaired in the non-relapsing group. This association of impaired suppressor-cell function with failure to relapse may indicate that suppressor cells have a pathogenetic role in MCN and that the therapeutic effect of cyclophosphamide in this disease is to diminish their function. Alternatively, the impaired suppressor-cell function in the non-relapsing group may be simply a marker of effective treatment with cyclophosphamide. The finding of long-term suppression of lymphocyte function after cyclophosphamide coupled with this drug's risks of causing malignancy and gonadal dysfunction reinforces the need for caution in its use in MCN.

Adolescent↗
PubMed1981

Depression of normal lymphocyte transformation by sera of patients with minimal change nephropathy and other forms of nephrotic syndrome.

Sera from patients with the nephrotic syndrome due to minimal change nephropathy (11 patients), membranous nephropathy (14 patients) and focal glomerulosclerosis (15 patients) inhibited the response of normal lymphocytes to the mitogen Concanavalin A. Although there was a tendency for the sera of patients with minimal change nephropathy to be more inhibitory than sera from the other two forms of nephrotic syndrome, this effect of nephrotic sera on normal lymphocytes is not confined to minimal change nephropathy. Until the exact nature of the inhibitor(s) is established, it is therefore not possible to state that impaired lymphocyte transformation by serum plays a pathogenetic role specifically in minimal change nephropathy. The susceptibility of nephrotic patients to infection may be due in part to the sera of the patients causing reduced lymphocyte function in vivo which leads to a defective immune response.

Adolescent↗
PubMed1978

Effects of catecholamine manipulations on three different self-stimulation behaviors.

Rats with self-stimulation electrodes in the medial part of lateral hypothalamus (LH) or in the lateral part of LH were trained to bar press, to run in a continuous, square-shaped runway, and to move their tails from side to side while otherwise restrained, all using LH stimulation on an FI 2 sec schedule as the reinforcement. At low doses of pimozide (a dopaminergic blocker) or of FLA-57 (a dopamine beta-hydroxylase inhibitor) different effects on rates of responding were observed on each of the three tasks at the two electrode placements, indicating that the rate reductions were not the results of specific performance effects of the drugs. The patterns of rate changes suggested that the effects of LH stimulation on behavior in the runway were primarily, but not exclusively mediated by a dopaminergic system; that the effects of LH stimulation on tail movement were primarily, but not exclusively mediated by a noradrenergic system; and that the effect of LH stimulation on bar pressing was mediated by both, or either of these substrates. These results suggest that the reinforcement of behavior by LH stimulation is flexibly mediated by at least two different neural systems.

Animals↗
PubMed1978

Effects of catecholamine manipulations on three different self-stimulation behaviors.

Rats with self-stimulation electrodes in the medial part of lateral hypothalamus (LH) or in the lateral part of LH were trained to bar press, to run in a continuous, square-shaped runway, and to move their tails from side to side while otherwise restrained, all using LH stimulation on an FI 2 sec schedule as the reinforcement. At low doses of pimozide (a dopaminergic blocker) or of FLA-57 (a dopamine beta-hydroxylase inhibitor) different effects on rates of responding were observed on each of the 3 tasks at the 2 electrode placements, indicating that the rate reductions were not the results of specific performance effects of the drugs. The patterns of rate changes suggested that the effects of LH stimulation on behavior in the runway were primarily, but not exclusively mediated by a dopaminergic system; that the effects of LH stimulation on tail movement were primarily, but not exclusively mediated by a noradrenergic system; and that the effect of LH stimulation on bar pressing was mediated by both, or either of these substrates. These results suggest that the reinforcement of behavior by LH stimulation is flexibly mediated by at least 2 different neural systems.

Animals↗