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Biomedical subjects

M M Brown

Publications and source records attributed to M M Brown.

At least 163 records · Page 9Linked to original sources
PubMed1985

Cerebral systemic lupus erythematosus presenting with catatonia.

A 13 year old girl with catatonia resulting from cerebral lupus is described. She had concurrent minor epileptic status, but abolition of her seizure activity failed to influence her catatonic state. She recovered after treatment with corticosteroids and immunosuppressive agents. Cerebral lupus should be considered in the differential diagnosis in patients presenting with catatonia.

Adolescent↗
PubMed1984

MIF-1 (Pro-Leu-Gly-NH2) decreases activity in Siamese fighting fish (Betta splendens).

The effects of MIF-1 (Pro-Leu-Gly-NH2) on activity and aggression of male Siamese Fighting Fish ( Betta splendens) were considered. Animals were given intraperitoneal injections of 0.0 or 10.0 mg/kg MIF-1. After a 10-minute delay, they were placed in a 10 gallon aquarium and their activity was monitored for 60 minutes. Although aggressive responses in the presence of suitable opponents were not reliably affected, as significant decrease in general activity was produced. This is compatible with differential effects of MIF-1 across species.

Aggression↗
PubMed1984

Effect of indomethacin on cerebral blood flow, carbon dioxide reactivity and the response to epoprostenol (prostacyclin) infusion in man.

Cerebral blood flow (CBF) has been measured using a non-invasive Xenon133 clearance technique in six normal subjects after 2 days pretreatment with oral indomethacin at a dose of 100 mg/day. The results were compared with placebo given in a double blind balanced cross-over design. Indomethacin was found to result in a reduction in resting CBF of about 25% but the reactivity of the cerebrovascular circulation to carbon dioxide was preserved at normal levels. Infusions of epoprostenol (prostacyclin, PGI2) at a dose of 5 ng/kg/min resulted in a reduction of CBF of about 10% after placebo but no significant change in CBF after indomethacin. The results suggest that prostaglandins are involved in the maintenance of cerebrovascular tone but not in the mechanism of cerebral vasodilation accompanying hypercapnia. The combination of indomethacin and PGI2 has been proposed as a treatment of cerebral artery spasm and the findings suggest that the combination therapy would not be accompanied by undesirable intracerebral steal.

Adult↗
PubMed1984

Effect of dietary fat on food intake, growth and body composition in rats.

The long-term ingestion of a fat-rich diet caused severe obesity in adult rats. Severe obesity developed in these animals without them having to increase caloric intake. Evidence for this comes from the observation that voluntary intake averaged 36,113 +/- 410 calories/rat per 60 wk for rats eating a high-fat diet (42% of calories from fat) compared to a value of 36,125 +/- 500 calories/rat per 60 wk for those eating a diet of Purina chow. Despite a similar caloric intake, carcass fat averaged 51 +/- 1% for rats eating the fat-rich diet but only 30 +/- 1% body fat for control animals eating the low-fat diet of Purina chow. These results indicate that a fat-rich diet does not always cause rats to overeat. Further, they clearly demonstrate that severe obesity can develop in the absence of hyperphagia provided the animals eat a fat-rich diet. Finally, a correlation coefficient of r = 0.76 between body weight and lean body mass was obtained for the Purina chow-fed rats and that of r = 0.66 was obtained for the fat-fed rats.

Animals↗
PubMed1984

Improper topical self-administration of ocular medication among patients with glaucoma.

Possible sequelae of improper administration of eyedrops include treatment failure, unnecessary use of additional medications and spread of infection. To determine the extent of improper topical self-application of ocular medications, 150 patients with glaucoma who were already using eyedrops were studied. Employing their customary methods of administration 19 (13%) of the patients were unable to place drops in both eyes after one or more attempts, and 120 (80%) of the patients failed to maintain the bottle's sterility during application. No significant relation was found between performance and age, sex, educational level, visual acuity or field, intraocular pressure, length of time the patient had been using eyedrops or, among the 100 clinic patients, whether the patient had received prior instruction in their use. The 50 private practice patients had all received prior instruction, by one physician, whereas only 62% of the clinic patients had, and there had been several instructors at the clinic. Significantly more (p less than 0.05) of the clinic patients than of the private practice patients failed to wash their hands before instilling the drops (97% v. 78%) and were unable to properly instil the drops in both eyes after one or more attempts (18% v. 2%). Therefore, uniform teaching probably improves the ability of patients to topically administer ocular medication.

Administration, Topical↗
PubMed1982

Effect of plasma exchange on blood viscosity and cerebral blood flow.

The effects of plasma exchange using a low viscosity plasma substitute on blood viscosity and cerebral blood flow were investigated in eight subjects with normal cerebral vasculature. Plasma exchange resulted in significant reductions in plasma viscosity, whole blood viscosity, globulin and fibrinogen concentration without affecting packed cell volume. The reduction in whole blood viscosity was more pronounced at low shear rates suggesting an additional effect on red cell aggregation. Despite the fall in viscosity there was no significant change in cerebral blood flow. The results support the metabolic theory of autoregulation. Although changes in blood viscosity appear not to alter the level of cerebral blood flow under these circumstances, plasma exchange could still be of benefit in the management of acute cerebrovascular disease.

Adult↗
PubMed1982

Effect of epoprostenol (prostacyclin, PGI2) on cerebral blood flow in man.

Cerebral blood flow has been measured using the non-invasive Xenon133 clearance technique in eight normal subjects during an infusion of epoprostenol (prostacyclin, PGI2) at a dose of 5 ng/kg/min. The results were compared with a control infusion of saline given in a balanced order. PGI2 was found to result in a reduction in cerebral blood flow of about 8%. PGI2 also caused a small drop in diastolic blood pressure and it is proposed that the fall in cerebral blood flow may have been the result of disturbed autoregulation. The findings suggest that the therapeutic use of PGI2 in patients with cerebral artery spasm would not be accompanied by undesirable intracerebral steal.

Adult↗
PubMed1982

Renin and aldosterone at high altitude in man.

Measurements have been made of hormonal changes relevant to salt and water balance during prolonged exposure to hypoxia to improve our understanding of the syndrome of acute mountain sickness. We have attempted to delineate the detailed inter-relationships between the renin-aldosterone and the vasopressin systems by a metabolically controlled study, involving an orthostatic stress (45 degrees head-up tilt) and an injection of a standard dose of ACTH to test adrenal responsiveness. Three Caucasian medical students underwent a 7-day equilibration at 150 m (Lima, Peru), followed by a 6-day sojourn at 4350 m (Cerro de Pasco, Peru) and a final 7 days at 150 m. Measurements were made of sodium and potassium balance, body weight and the 24-h renal excretion of vasopressin, cortisol and aldosterone 18-glucuronide. These variables showed little change, except for that of aldosterone 18-glucuronide, which fell sharply at altitude and rebounded even more sharply on return to sea level. At altitude, basal plasma levels of renin activity and aldosterone fell, and the response to orthostasis was attenuated, but the fall of plasma renin activity, as compared to plasma aldosterone, was delayed; on return to sea level this dissociation was exacerbated with the return of normal renin responsiveness lagging behind that of aldosterone. We suggest that unknown factors which dissociate the orthodox renin-aldosterone relationship, other than the activity of the angiotensin I-converting enzyme, are operative on exposure to hypoxia.

Adult↗
PubMed1980

Skin immunopathology in system lupus erythematosus.

The role of skin immunopathology in the evaluation and management of patients with systemic lupus erythematosus (SLE) remains controversial. Four simultaneous biopsy specimens from nine patients with SLE (two from buttock and two from forearm skin) were evaluated. Specimens from eight of nine patients showed symmetrical deposits. A poor correlation of skin biopsy score and clinical activity score was noted. A positive correlation was noted between serum C3 levels and skin biopsy score, but a poor correlation was noted with criteria for active nephritis with the exception of microscopic hematuria. In most instances, findings from a single skin biopsy specimen are sufficient and of diagnostic value but correlate poorly with other measurements of disease activity. Serial studies suggested that persistence of cutaneous deposits for many months after flares of SLE may in part explain poor correlation with active disease.

Antigen-Antibody Complex↗
PubMed1980

Lack of side effects from topically administered 10% phenylephrine eyedrops. A controlled study.

A prospective double-blind study was designed to determine the systemic hypertensive effects of topically administered 10% aqueous buffered phenylephrine hydrochloride vs topically administered 1% aqueous tropicamide, a belladonna alkaloid devoid of vasopressor effect. One hundred persons received phenylephrine, while 50 persons received tropicamide. One drop of coded drug was administered in both eyes of each patient at two-minute intervals over a four-minute period. Blood pressure and pulse rate were measured immediately prior to drop instillation, and 5, 15, and 30 minutes following instillation of the final set of drops. Mean blood pressure and pulse rate dropped from baseline values in both groups at 5, 15, and 30 minutes after drug administration. There was no statistically significant difference between the experimental and control groups with respect to drug effect on either blood pressure or pulse rate throughout the study.

Adolescent↗
PubMed1980

Strength training effects on aerobic power and short-term endurance.

Nine men participated in an exercise program (five days a week for 10 weeks) that was designed to strengthen the quadriceps muscles. This study was undertaken to determine if heavy resistance training results in an increase in endurance, Vo2max and whether the differences that are normally observed during bicycle and treadmill Vo2max measurements in the same individuals are strength-related. Following training, endurance time to exhaustion significantly increased while cycling (47%) and while running (12%), when the subjects exercised at 100% of their pretraining Vo2max. There was a small increase in Vo2max (4%, P < 0.05) during bicycle exercise (3.40 l.min-1 to 3.54 l.min-1) after training, but no significant differences were observed when expressed in (ml.kg-1.min-1). Strength training had no effect on Vo2max when measured during treadmill exercise. Absolute differences between bicycle and treadmill Vo2max were essentially the same after training as before. Lactate concentration in blood after the bicycle and treadmill endurance tests were not elevated to a greater extent after training. Thigh girth increased significantly and muscle strength increased 40% with the training. These findings provide evidence that HRT is capable of dramatically increasing short-term endurance, when the muscles involved in the training are used almost exclusively during the testing without an accompanying increase in Vo2max. These data also suggest that the differences in Vo2max between bicycle and treadmill exercise are not the result of inadequate muscle strength.

Adolescent↗