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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 829 records · Page 46Linked to original sources
PubMed1987

Interface pressures in above-knee sockets.

The interface pressures in above-knee sockets of amputee patients were measured during the stance phase of the gait cycle. The pressures were monitored with a pneumatic sensor array that covered the inside of the socket. A pressure map of the socket surface was developed. This map has been related to the fit of the prosthetic socket. The pressures generated by the quadrilateral socket and the Normal Shape Normal Alignment (NSNA) socket were compared. Significant variations were noted in pressure distribution between the two sockets, but the magnitudes of the pressures in well-fitting sockets of both types were similar. Thus, magnitude of pressure in an above-knee socket may provide a more useful guide than distribution for predicting the fit of an appliance.

Artificial Limbs↗
PubMed1987

Moderately elevated blood lead levels: effects on neuropsychologic functioning in children.

Investigations of moderately elevated lead levels and children's cognitive functioning have yielded conflicting results, although studies showing no effects used measures of limited sensitivity and breadth. In this study, a comprehensive neuropsychologic battery was used to determine whether deficits would be revealed. An experimental group of 15 children with a past history of moderately elevated lead levels, but subsequently without increased lead levels for at least a year, were compared with a control group matched by residential area, socioeconomic status, parental IQ, age, and gender. The experimental groups' performance was lower on the battery overall and on measures of motor skill, memory, language, advanced spatial functions, and concentration. The results suggest that exposure to moderately elevated lead levels exerts significant and nontransient effects on cognitive functions.

Child↗
PubMed1987

Treatment of seasonal affective disorder with morning light.

Three subjects afflicted with seasonal affective disorder (winter depression) were treated with 2-hour morning light exposures. Within 2 to 5 days, all responded, and remission of their symptoms was sustained during the 2-month treatment period.

Adult↗
PubMed1987

The effect of dietary protein restriction on the progression of diabetic nephropathy. A 12-month follow-up.

Eight patients with insulin-dependent diabetes mellitus and progressive renal dysfunction as determined by serial serum creatinine values were placed on a diet containing 40 g of high-biologic-value protein. Selected factors of renal function were determined over a 12-month interval. After the first 12 months of the protein-limited diet, creatinine clearance was not significantly changed. The rate of decline in renal function during the dietary protein restriction slowed from the rate over the prior 12 months in seven patients. Five of these seven demonstrated improvement in renal function. Daily urinary protein excretion decreased significantly, from 2105 +/- 1355 to 142 +/- 164 mg/d (2.11 +/- 1.36 to 0.14 +/- 0.16 g/d). Body weight did not change significantly, whereas serum albumin level increased significantly from a mean of 3.5 +/- 0.6 to 4.3 +/- 0.3 g/dL (35 +/- 6 to 43 +/- 3 g/L). These findings suggest that dietary protein restriction has a beneficial role in treating patients with diabetic nephropathy.

Adult↗
PubMed1986

Familial malignant melanoma.

Characteristics associated with familial compared with nonfamilial malignant melanoma were assessed. These data were obtained from consecutive prospectively completed questionnaires on 1169 cases of cutaneous malignant melanoma. Of these, 69 patients indicated a positive family history for this cancer. Among the various clinical and histological variables compared, those that significantly correlated with the familial occurrence of malignant melanoma include younger age at first diagnosis, smaller diameter of the lesion, lower Clark level, decreased frequency of nonmelanoma skin cancer, and reduced prevalence of noncutaneous cancer. Increased awareness of malignant melanoma among family members could account for some of these observations. Identification of the familial variety of malignant melanoma has practical implications concerning early detection and prompt intervention.

Age Factors↗
PubMed1986

Regulation of glucokinase activity in the domestic fowl.

The factors which regulate soluble and particulate glucokinase and hexokinase activity in the liver of domestic chickens has been investigated. Pretreatment with oral administration (via tube feeding) of glucose plus injection of insulin resulted in a significant increase in the activity of soluble (p less than 0.01) and particulate (p less than 0.01) glucokinase activity whereas fasting for 48 hours reduced glucokinase and hexokinase activity (p less than 0.01) in the particulate fraction only. Treatment of fed chickens for 2 weeks with thyroxine (50 micrograms: i.m. daily) plus triiodothyronine (50 micrograms) resulted in a marginal decrease (NS) in soluble glucokinase activity but significantly increased soluble hexokinase (p less than 0.05) activity. Thyroidectomized animals showed a decline in both soluble glucokinase (p less than 0.01) and hexokinase (p less than 0.025) activity. There was no effect of thyroid hormone manipulation on particulate glucokinase activity although there was a significant reduction in particulate hexokinase activity (p less than 0.05) in thyroidectomized birds. These data establish a physiological role for the glucokinase enzyme activity in avian carbohydrate metabolism and suggest that in contrast with the mammal, the particulate fraction is the more physiologically important enzyme.

Animals↗
PubMed1986

Interaction of nonsteroidal anti-inflammatory drugs with antihypertensive and diuretic agents. Control of vascular reactivity by endogenous prostanoids.

Indomethacin and some other nonsteroidal anti-inflammatory drugs partially antagonize the blood pressure lowering effect of drugs used to treat hypertension. They can also produce a mild elevation of blood pressure in normotensive individuals. The elevated arterial pressure caused by these agents is associated with increases in the vascular resistance of mainly the renal and splanchnic beds. This may be due to direct inhibition of the synthesis of vasodilator prostanoids, or it may be due to indirect potentiation of the action of the sympathetic nervous system or of angiotensin II. Nonsteroidal anti-inflammatory drugs also cause renal retention of sodium and this probably contributes to their hypertensive effects. In humans, the sodium retention may involve increased reabsorption in the proximal tubule. Although a direct tubular action is possible, these drugs may change proximal sodium reabsorption by their vascular effects. However, the exact mechanism is not understood. These interactions are clinically significant and may complicate the treatment of common diseases.

Animals↗
PubMed1986

Does angiotensin-II protect against strokes?

In the Medical Research Council trial for the treatment of mild hypertension, bendrofluazide showed an unexpected and sizeable benefit compared with propranolol in the reduction of stroke. It is suggested that this difference reflects the opposing actions of these drugs on the renin-angiotensin system. The hypothesis that angiotensin-II protects the distal smaller cerebral vessels, which are the usual site of vessel rupture in intracerebral haemorrhage, indicates that long-term benefit of angiotensin-converting-enzyme inhibitors in the treatment of hypertension cannot be assumed.

Angiotensin II↗
PubMed1986

Use of M-mode echocardiography in the diagnosis of congestive cardiomyopathy in Doberman pinschers.

M-mode echocardiography performed on 3 groups of Doberman Pinschers--healthy, early cardiomyopathy, and advanced cardiomyopathy (pulmonary edema present). Echocardiographic measurements in those dogs with advanced cardiomyopathy were typical of the disease in human beings and other breeds of dogs. Significant differences were detected between dogs with early cardiomyopathy and those with advanced disease. The E-point septal separation was determined to be the most sensitive and specific criterion for the recognition of early cardiomyopathy.

Age Factors↗
PubMed1986

Thermoradiotherapy for persistent cancer in previously irradiated fields.

Among some 300 patients undergoing clinical trails with localized radiofrequency hyperthermia, 42 whose cancers had persisted or recurred after conventional radiotherapy were selected for additional limited radiation plus hyperthermia. There were 10 complete responses to therapy, 13 partial responses and one patient was considered nonevaluable. In the remaining 18 patients there was minor regression, stabilization or progression of the tumor. After completion of treatment, five of the tumors appeared operable and surgical resection was accomplished in four. The results of this study support the concept that hyperthermia has a potentiating effect when used in conjunction with radiation therapy.

Adenocarcinoma↗
PubMed1986

Human-human hybridomas secreting monoclonal antibodies to the Mr 195,000 Plasmodium falciparum blood stage antigen.

Using the human lymphoblastoid cell line, GM 4672, and PBL of Gambian adults immune to Plasmodium falciparum (Pf) malaria, we have produced human-human hybridomas and selected those that produce mAb against Pf antigens. The fusion frequency, using PWM-stimulated donor lymphocytes was between 6.8 X 10(-5) and 1.5 X 10(-6). Using immune fluorescence, immune precipitation, and Pf in vitro growth inhibition, we cloned four hybridomas that reacted with the Pf Mr 195,000 schizont/merozoite protein. The differences in proteins immune precipitated and in growth inhibition indicate that, during development of protective immunity against Pf malaria, a spectrum of antibodies is produced reacting with different epitopes on the same antigen. Only a portion of these antibodies exhibits biological activity, suggesting that the recognition of certain epitopes is required for the development of a protective immune response.

Animals↗
PubMed1986

Oocyte maturation inhibitor activity in human follicular fluid: quantitative determination in unstimulated and clomiphene citrate- and human menopausal gonadotropin-stimulated ovarian cycles.

Since removal of the oocyte from the intrafollicular milieu allows meiotic resumption and germinal vesical breakdown to proceed, the concept of an intrafollicular oocyte maturation inhibitor (OMI) has evolved. Accordingly, we asked the following questions: Is there OMI activity in human follicular fluid? Does OMI activity change with ovarian hyperstimulation? and Does OMI activity correlate with oocyte fertilization or the concentration of steroids in the corresponding follicular fluid? Fresh cumulus enclosed porcine oocytes from small follicles were incubated with human follicular fluid aspirates from normally menstruating patients with or without treatment: unstimulated follicles (N = 10), clomiphene citrate (150 mg/day) (N = 10)-treated cycles, and human menopausal gonadotropin (hMG) (N = 12)-treated cycles. A lyophylized porcine follicular fluid standard and serum-free culture media were used as positive and negative controls, respectively. After a 40-hr incubation with test materials, the oocytes were fixed, stained, and evaluated for oocyte maturation as determined by germinal vesical breakdown. Human follicular fluid, estradiol, progesterone, androstenedione, and testosterone levels were determined by radioimmunoassay. The 50% inhibitory dose (ID50) for OMI activity in follicular fluid from untreated, spontaneously menstruating women was less than that for follicular fluid from clomiphene-stimulated patients, which was less than that for follicular fluid from hMG-stimulated patients. The difference between OMI values from untreated and hMG-stimulated follicular fluids was statistically significant. Human oocytes removed from follicular fluid with higher OMI activity tended not to fertilize in vitro compared to the relatively lower OMI activity present in follicular fluid yielding oocytes which did fertilize.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗