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S Brown

Publications and source records attributed to S Brown.

At least 685 records · Page 38Linked to original sources
PubMed1982

Antimicrobial susceptibility of gonococci isolated in the Central African Republic.

Using agar dilution techniques, we determined the minimum inhibitory concentrations (MIC) of 11 antimicrobials for 70 isolates of Neisseria gonorrhoeae obtained in Bangui, Central African Republic. These gonococci were found to be fairly susceptible to commonly used antibiotics: only 3 isolates (4%) had a penicillin MIC >/= 1.0 mug/ml and 6 (9%) had a tetracycline MIC >/= 2.0 mug/ml. With regard to other antibiotics, 54 isolates (77%) had an erythromycin MIC >/= 0.25 mug/ml, all had a spectinomycin MIC </= 16 mug/ml, and 32 (46%) had a sulfamethoxazole/trimethoprim MIC >/= 9.5/0.5 mug/ml. None of these isolates produced penicillinase.This study has helped to provide a rational basis for establishing national gonorrhoea treatment recommendations in the Central African Republic.

Anti-Bacterial Agents↗
PubMed1981

Real-time ultrasound observation of breathing and movements in the fetal lamb.

In seven pregnant ewes with catheters chronically implanted in the fetus, real-time ultrasound observations of fetal breathing and body movements were correlated with direct measurements of fetal arterial and tracheal pressures, heart rate, and intrauterine pressure. There was excellent correlation between the ultrasound record of fetal breathing and recordings of intratracheal pressure changes even when breath amplitude was low or frequently was high. Fetal body movements (stretches, rolls, kicks) were observed during both breathing and nonbreathing periods; vigorous movements were accompanied by rapid deflections of the amniotic and tracheal pressure traces. Movement was frequently accompanied by transient increases or decreases in heart rate. The results indicate that real-time ultrasound is an accurate method of observation of fetal movement in pregnant sheep and is particularly valuable when combined with direct measurements of fetal physiologic parameters.

Animals↗
PubMed1981

Brief clinical report: 46,XX, del (18p) with amenorrhea, hypothyroidism, and ptosis.

A 17-year-old girl was initially evaluated because of primary amenorrhea and lack of sexual development. Chromosome studies demonstrated the presence of 46,XX, del (18p). The patient is now 21 years old and still has not menstruated. This is the first reported case of 46,XX, del (18p) presenting with primary amenorrhea. The case is of additional interest in that ptosis, a common finding in this syndrome, was not present at birth but was first noted at age 9.

Adult↗
PubMed1981

Human suppressor cells: evidence of functionally distinct subsets.

Human suppressor cells (SC) differing in both kinetic characteristics and degree of specificity were induced in vitro either by Concanavalin A (CON A) (10 microgram/ml) or by repeated stimulation with allogeneic cells. CON A SC caused a characteristic early peak in blastogenesis (Day 2) when cocultured with fresh autologous cells in the presence of either CON A or augmented response fell rapidly to values 50--90% below positive controls by the usual optimal day for the particular stimulus. Treatment with 5-bromodeoxyuridine and light during rapid proliferation ablated the early responses but increased the later responses (i.e., reduced the suppression). The cells mediating both the early rise and late suppression were found to belong to a subset of T cells that lost their ability to form SRBC rosettes (theophylline sensitive) in the presence of the phosphodiesterase inhibitor, theophylline, and were inactivated by mitomycin C. In contrast, SC induced by repeated allogenic stimulation were suppressive in MLC but not CON A cultures, did not initiate early blastogenesis in the presence of naive cells and were partially mitomycin resistant. The mitomycin resistant SC induced by allogeneic stimulation are found in the theophylline resistant T-cell subset. These data are consistent with a model of human SC differentiation in which at least two subsets may be present: (1) a mitomycin sensitive, nonspecific cell that participates in an obligatory early autologous recognition event (induction?) and (2) a later occurring, more mitomycin resistant effector cell that appears to acquire specificity for the response that it affects.

Bromodeoxyuridine↗
PubMed1981

Increased activity of rat intestinal lactase due to increased intake of alpha-saccharides (starch, sucrose) in isocaloric diets.

The adaptability of intestinal microvillar alpha-disaccharidases to the variation of alpha-saccharide content in the diets is well established, but the influence of these sugars on the activity of microvillar lactase (neutral beta-galactosidase) has heretofore been considered negligible or non-existing. In two experiments rats were fed isocaloric diets where the carbohydrate (starch or sucrose) content versus fat content was varied. (High carbohydrate diets: 71% of calories as carbohydrate and 5% of calories as fat; low carbohydrate diets: 6 and 73% calories, respectively). Experiment 1: male and female rats had access to experimental diets only from day 12 postnatally and were killed at age 56 days. Experiment 2: male rats were fed experimental diets starting on day 73 postnatally and killed 3, 7, 14 and 28 days later. Rats fed the high carbohydrate diets exhibited a significant increase in activity (specific and total per segment) of lactase in all three intestinal segments compared to rats fed the low carbohydrate diets. Changes in the activity of sucrase and maltase paralleled those of lactase activity. These experiments have thus demonstrated clearly the influence of variation in alpha-saccharide content in the diet upon lactase activity. Further experiments are needed to determine the active principle of this dietary adaptation.

Adaptation, Physiological↗
PubMed1981

Airway reactivity in cotton bract-induced bronchospasm.

Most healthy subjects challenged with cotton bract extract demonstrate some degree of bronchospasm. This response has been associated with the endogenous production of histamine by the inhalation of cotton bract extract. We examined whether this responsiveness reflects increased sensitivity to histamine. Thirty-one healthy subjects were screened for sensitivity to cotton bract extract administered by nebulization. Pulmonary function was measured using partial expiratory flow-volume curves on which flows at 60% of the control vital capacity below total lung capacity were measured (MEF40%(P)). Responders were defined as subjects who exhibited a 20% or greater decrease in MEF40%(P) after 10 min inhaling cotton bract extract. Of those screened, 10 subjects were responders. From the remaining nonresponders, 11 consecutive subjects were selected. The maximal decrease in MEF40%(P) in responders was 40.5 +/- 5.1%, compared to 10.9 +/- 2.2% in nonresponders. The dose-response relationship for histamine was measured in all subjects, using inhalations of progressively more concentrated histamine solutions. The mean +/- SEM threshold for the responders was 38.4 +/- 7.4 mg of histamine per ml, compared to 42.2 +/- 6.8 mg of histamine per ml for responders (difference not significant). The percentage decrease in MEF40%(P) at the threshold dose was 27.6 +/- 3.7% for responders and 32.4 +/- 5.2% for nonresponders (difference not significant). We conclude that healthy subjects sensitive to cotton bract extract do not exhibit increased reactivity to histamine. This suggests that responders are not, in general, subclinical asthmatics, and that the difference between responders and nonresponders to CBE is not due to increased histamine sensitivity among responders.

Adult↗
PubMed1980

Spontaneous increase in erythropoietin and hematocrit value associated with transient liver enzyme abnormalities in an anephric patient undergoing hemodialysis.

An anephric patient undergoing hemodialysis experienced an increase in his hematocrit value (19 +/- 1 per cent to 31 +/- 1 per cent) as a result of increased erythropoiesis (reticulocyte count 1.8 per cent to 7.4 per cent). This increase occurred in concert with an elevation of the patient's liver enzyme levels and was maintained for four months. The hematocrit value returned to its base line only after the liver function tests showed improvement. During the period when the hematocrit value was increasing, the circulating level of erythropoietin was elavated to 71.0 mU/ml--a level higher than that seen in either anephric or nephric patients undergoing dialysis. When the hematocrit value and liver enzyme levels had returned to their base line values, the erythropoietin level was 4.3 mU/ml--a level in the range seen in anephric patients undergoing dialysis. The observations in this patient suggest that under certain circumstances, the liver can produce erythropoietin in the anephric patient; and, more importantly, that the bone marrow of at least some uremic patients is capable of responding to the endogenous erythropoietin.

Bone Marrow↗
PubMed1980

Ticrynafen in anephric patients: effects on uric acid and pharmacokinetics.

Ticrynafen was given to 6 anephric patients undergoing maintenance hemodialysis. Ticrynafen was given daily for the 3 days between hemodialyses. Ticrynafen had no effect on the interdialysis rise in serum uric acid levels. Ticrynafen did not accumulate in serum, but levels of metabolites continued to rise over the 3 days. Hemodialysis (5 hr) reduced levels of ticrynafen by 38% but had less effect on metabolite levels. There was no effect on serum cholesterol or triglycerides.

Adult↗
PubMed1980

Mechanism and prevention of cardiac arrhythmias in chronic hemodialysis patients.

We monitored, by the Holter method, 23 clinically stable maintenance hemodialysis patients for 5 +/- (SEM) 2 hours before hemodialysis, 5.0 +/- 0.5 hours during hemodialysis, and 13 +/- 3 hours after hemodialysis. Of 23 patients, 9 (39%) had unexpected frequent or complex ventricular arrhythmias recorded and after hemodialysis with a potassium dialysate bath concentration of 2.0 mEq/liter. Patients with ventricular arrhythmias were more likely to be using digoxin (8/9 vs. 1/4) and to have evidence of left ventricular hypertrophy (9/9 vs. 7/4 than were those patients without arrhythmias. Of these 9 patients with arrhythmias, 6 underwent repeat Holter monitoring during multiple dialysate protocols. Of the 6 patients, 4 had a significant reduction in the frequency of ventricular ectopy when a dialysate of 3.5 mEq/liter potassium was used (P < 0.05), but of these 6, 3 still had complex arrhythmias. The use, however, of a 3.5 mEq/liter potassium dialysate plus the administration of a 400-mg dose of quinidine sulfate orally 45 min prior to hemodialysis was successful in reducing ventricular ectopic frequency and complexity in all the patients studied. Conclusion. Maintenance hemodialysis patient using digoxin and with left ventricular hypertrophy have an unexpectdly high indicence of occult, potentoial serious, ventricular arrhythmias during and after hemodialysis, revealed by Holter monitoring. There is preliminary evidence that a low-potassium bath concentration may play a role in predisoposing patients to these arrhythmias. Further prospective studies with largaer number of patients will be needed, however, to evaluate the significance of these findings.

Adult↗