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Biomedical subjects

J D Brown

Publications and source records attributed to J D Brown.

At least 109 records · Page 6Linked to original sources
PubMed1986

Stress and well-being in adolescence: the moderating role of physical exercise.

Adolescence is quite often a period of personal adjustment and stress, and previous research has found that adolescents are vulnerable to the negative effects of stressful life events. The present research sought to determine whether a subset of adolescent girls, those who routinely engage in physical exercise, escape stress-induced disturbances in physical and psychological well-being. Self-report measures of stressful life events, physical and emotional well-being, and exercise habits were obtained from 220 females of secondary school age. In accordance with experimental hypotheses, stress had a substantial debilitating effect on physical and emotional health among persons who reported exercising infrequently but not among those who reported exercising regularly. Potential mediating mechanisms are identified and implications of the findings for primary prevention programs targeted toward adolescents are discussed.

Adolescent↗
PubMed1986

Critically ill polyneuropathy: electrophysiological studies and differentiation from Guillain-Barré syndrome.

A polyneuropathy of varying severity has been observed in association with sepsis and critical illness in 15 patients. Since clinical evaluation is often difficult, electrophysiological studies provided definitive evidence for polyneuropathy. These revealed reductions in the amplitudes of compound muscle and sensory nerve action potentials, the most marked abnormality. Near-nerve recordings confirmed such reductions for sensory fibres. Needle electromyography revealed signs of denervation of limb muscles. Phrenic nerve conduction and needle electromyographic studies of chest wall muscles suggested that the polyneuropathy partially explained difficulties in weaning patients from the ventilator, an early clinical sign. No defect in neuromuscular transmission was demonstrated, despite the use of aminoglycoside antibiotics in some patients. In those who survived the critical illness, clinical and electrophysiological improvement occurred. The 15 critically ill polyneuropathy patients were compared with 16 Guillain-Barré syndrome patients observed during the same period. The analysis showed that the two polyneuropathies are likely to be separate entities that can be distinguished in most instances by the predisposing illness, electrophysiological features and cerebrospinal fluid results.

Aged↗
PubMed1985

Rapid enzyme system for the identification of pathogenic Neisseria spp.

Gonochek II is a combination of three enzyme substrates in one tube which will give a rapid identification (30 min) of those pathogenic Neisseria spp. which can be isolated on Thayer Martin or similar selective media. Eighty isolates were tested by Gonochek II and a carbohydrate utilization method; total agreement was achieved between the two methods.

Aminopeptidases↗
PubMed1984

Increased prevalence of mitral valve prolapse in patients with migraine.

Patients with classic migraine (69 women and 31 men) selected randomly from a practice list of over 1000 were matched for age, sex and neighbourhood with 100 people who did not have headache problems, and both groups underwent M-mode and two-dimensional echocardiography and clinical examination by cardiologists blinded to the subjects' clinical status. The mean ages were 34.9 +/- 11.3 years for the migraine group and 33.1 +/- 9.9 years for the control group. Definite and possible mitral valve prolapse (MVP), diagnosed according to predefined echocardiographic criteria, were found about twice as often in the migraine group as in the control group (in 15 v. 7 and 16 v. 8 patients respectively); the echocardiograms were definitely normal in 69 migraine patients and 85 controls (chi 2 = 8.39, p less than 0.025). Altogether 25% of the migraine group and 11% of the control group had evidence of MVP from a combination of the echocardiographic and auscultatory findings (chi 2 = 5.72, p less than 0.025). The odds ratio was 2.7, with 95% confidence limits of 1.17 and 6.29. The association between migraine and MVP has implications for the understanding of platelet abnormalities and episodes of cerebral ischemia occurring in both these conditions.

Adult↗
PubMed1984

Pyomyositis. Report of 18 cases in Hawaii.

Eighteen patients with pyomyositis were seen at a large hospital in Hawaii. Most were healthy young men or boys, and eight had never traveled abroad. Fever, muscle pain and swelling, and leukocytosis were common, but only seven had erythema or fluctuance. A single large muscle was infected in 14, and two to three muscles were infected in the others. Pyomyositis mimicked cellulitis, muscle hematoma, thrombophlebitis, appendicitis, and neoplasm. Staphylococcus aureus was found in 13, and Streptococcus pyogenes was found in two. Bacteremia occurred in 29% (5/17). Drainage and antimicrobial agents were usually effective therapy, but one patient died and another had CNS damage. The pathogenesis is uncertain, but 12 had nonpenetrating muscle injury and 13 had pyoderma, suggesting that bacteria invade injured muscle via the bloodstream or lymphatic system.

Adolescent↗
PubMed1984

Internuclear ophthalmoplegia and "optic neuritis": paraneoplastic effects of bronchial carcinoma.

A 56-year-old man developed bilateral internuclear ophthalmoplegia and "optic neuritis" as remote effects of a bronchial carcinoma. These clinical findings correlated pathologically with secondary demyelination of the medial longitudinal fasciculus and with round cell infiltration and adhesive arachnoiditis of the optic nerve. There was no evidence of CNS metastasis. "Optic neuritis" and internuclear ophthalmoplegia may be paraneoplastic effects of systemic cancer.

Carcinoma, Bronchogenic↗
PubMed1983

Neoplastic conversion of rat liver epithelial cells in culture by ethionine and S-adenosylethionine.

Rat liver epithelial cells were grown in the presence of the hepatocarcinogen, DL-ethionine, for 12 weeks. The cells were then cultured for an additional 32 weeks in carcinogen-free medium. At approximately monthly intervals, the cells were tested for transformation by assaying their ability to grow in soft agar and to produce tumors when injected s.c. into irradiated syngeneic rats. After a total of 34 weeks in culture, cells treated with 7.5 mM DL-ethionine were transformed according to both criteria. The experiment was repeated using medium in which methionine was replaced by its metabolic precursor, homocysteine. The cells were treated for 12 weeks with L-ethionine and its metabolite, S-adenosyl-L-ethionine (L-AdoEt), then cultured in their absence in methionine-containing medium for an additional 24 weeks. After a total of 20 weeks in culture, cells treated with 0.375 mM L-ethionine and cells treated with 0.2 mM L-AdoEt produced tumors following their injection into animals. Positive growth in soft agar was observed 5 and 11 weeks later, respectively. A total of 31 weeks in culture was required before cells treated with 0.2 mM L-ethionine became tumorigenic. Furthermore, tumors resulting from the injection into animals of cells treated with 0.2 mM L-ethionine arose 8-10 weeks later than did the corresponding tumors arising from the cells treated with 0.2 mM L-AdoEt. Thus, the results indicate that AdoEt may be a proximal carcinogenic metabolite of ethionine.

Adenosine↗
PubMed1982

Heredofamilial syndrome of spastic paraplegia, dysarthria and cutaneous lesions in ive siblings.

Five children, three sisters and two brothers aged between three months and 12 years, are described. They all developed a facial desquamating rash of butterfly distribution at the age of about two months, and motor retardation which later was characterized by spasticity, predominantly affecting the lower limbs. The three children who were old enough for speech to be tested had dysarthria. There was no family history of neurological disease, nor was there consanguinity among the parents or grandparents. EEGs were diffusely abnormal in four of the five children, but did not show any specific or diagnostic features. Plasma immunoglobulin tests were normal, and tests for collagen disease were negative. The authors are not aware of previous reports of this condition, but believe that it is a variant of familial spastic paraplegia, with atypical features.

Child↗
PubMed1980

Kober reaction kinetics and their influence on the design of assays for oestrogens in urine during pregnancy.

Rates of reaction of different oestrogens in Kober reagent vary greatly. Rate constants were measured between 100 degrees C and 150 degrees C. Oestradiol, oestrone, 16-oxo-oestradiol, 16 alpha hydroxyoestrone, 16-epioestriol and urine pool show two sequential first order reactions at 100 degrees C; oestriol and its conjugates give a single reaction (slower than the other oestrogens except for the very slow oestretrol). Above 120 degrees C differences decrease, all oestrogens having one rate for Kober product formation: the decay reaction, which is also first order, becomes significant. Oestriol and its conjugates have relatively high apparent activation energies in the Kober reaction (120-138 kJmol-1) compared to other oestrogens studied (105-124 kJmol-1). The apparent activation energy for the decay reaction is the same within experimental error (115 +/- 3 kJmol-1). This is consistent with a common product formed from oestrogen reacting with Kober reagent. Analytical methods must respond similarly to major urinary oestrogens. Appropriate conditions include 100 degrees C for at least 20 min or 135 degrees C for 3 to 4 minutes.

Autoanalysis↗