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Biomedical subjects

M McDermott

Publications and source records attributed to M McDermott.

161 records · Page 9Linked to original sources
PubMed1973

Rubidium influx into rat skeletal muscles in relation to electrical activity.

1. Rates of (86)Rb influx were compared in vivo over 2, 4 and 6 hr periods in various tonic and phasic muscles of rat following its I.P. injection. During the 2 hr period its influx rate into soleus was about 4 times that of the vastus with the EDL muscles at an intermediate rate. Uptake by diaphragm was fastest reaching equilibrium within 2 hr.2. Unilateral section of the sciatic nerve 48 hr before (86)Rb injection reduced isotope uptake into soleus to about 50% of its contralateral control muscle over a 4 hr period. In EDL muscles on the other hand nerve section increased influx by about 75% of control in conscious rats and more than doubled influx in anaesthetized rats.3. Tenotomy of soleus reduced (86)Rb influx to 40% of control, but tenotomy in EDL was without effect in influx.4. Uptake of urea into muscles within 5 min of its I.V. injection was used to determine the possibility of muscle blood flow determining (86)Rb influx. Accumulation of urea was not significantly different in control and denervated EDL muscles nor between soleus and vastus muscles in anaesthetized rats, so it seems unlikely that blood flow is important here.5. Membrane depolarization in response to addition of 30 mM rubidium to external bathing fluid was greater in the case of denervated than in control EDL muscles which was in keeping with the greater (86)Rb influx seen in the former muscles. The ouabain sensitivity of rubidium-induced depolarization in the denervated EDL muscles would suggest, however, that rubidium enters the fibres actively.

Animals↗
PubMedDate not supplied

Thyroid-stimulating hormone stimulation tests in cardiomyopathic Doberman pinschers: a retrospective study.

Thyroid-stimulating hormone (TSH) response tests were performed in 152 Doberman Pinschers. Seventy-nine dogs had cardiomyopathy (46 were in congestive heart failure [CHF] and 33 were not in CHF). Seventy-three dogs were presented for noncardiac problems (15 with skin disease, 21 with neurologic disease, 20 with internal medicine disorders, and 17 with other problems), although some may have had cardiomyopathy. The TSH response test results in the cardiomyopathic group were interpreted as normal or euthyroid-sick in 45 (57%) dogs, abnormal in 23 (29%) dogs, and equivocal in 11 (14%) dogs. The prevalence of hypothyroidism in the CHF and non-CHF cardiomyopathy groups was not different. Among the dogs presented for noncardiac problems, 27 (37%) were assessed as normal or euthyroid-sick, 29 (40%) as hypothyroid, and 17 (23%) as equivocal. No significant differences were found in the prevalence of hypothyroid test results among the subgroups of these dogs. The prevalence of hypothyroidism was not higher in the cardiomyopathic group compared to the other group, and 63 and 49% of cardiomyopathic dogs with or without CHF, respectively, tested as either euthyroid or euthyroid-sick.

Animals↗
PubMedDate not supplied

The possible biological role of aldosterone metabolites.

Following the incubation of aldosterone with microsomes from liver of adrenalectomized male rates, a previously unidentified polar neutral metabolite of aldosterone, designated "peak A" material, was isolated and purified using high pressure liquid chromatography. This peak A material, which contains a reduced hydroxylated metabolite of aldosterone, was shown to possess 2% to 3.5% of the mineralocorticoid activity relative to aldosterone. When bovine adrenal glomerulosa cells were incubated with peak A material (3 and 10 micrograms/ml), the binding of 125I-angiotensin II was inhibited by 20% and 36%, respectively. The mineralocorticoid activity of the six possible ring A reduced metabolites was tested. The 5 alpha-reduced metabolites were more potent than the 5 beta-, and the 3 alpha- were more potent than the 3 beta-reduced metabolites. The renal and extrarenal transformations of aldosterone to the polar and nonpolar (reduced) metabolites and their possible role in the accepted mechanism of action of aldosterone is discussed.

Adrenal Glands↗
PubMedDate not supplied

Living alone after myocardial infarction. Impact on prognosis.

OBJECTIVE: To determine if the presence of a disrupted marriage or living alone would be an independent prognostic risk factor for a subsequent major cardiac event following an initial myocardial infarction. DESIGN: Prospective evaluation in the placebo wing of a randomized, double-blind drug trial in patients with an enzyme-documented acute myocardial infarction who were admitted to a coronary care facility. Data for living alone and/or a marital disruption were entered into a Cox proportional hazards model constructed from important physiologic and nonphysiologic factors in the same database. SETTING: Multicenter trial in a mixture of community and academic hospitals in the United States and Canada. PATIENTS: All consenting patients who were 25 to 75 years of age and without other serious diseases were enrolled (placebo, N = 1234) within 3 to 15 days of the index infarction and followed for a period of 1 to 4 years (mean, 2.1 years). Nine hundred sixty-seven patients were followed for 1.1 years and 530 for 2.2 years. PRIMARY OUTCOME MEASURE: Recurrent major cardiac event (either recurrent nonfatal infarction or cardiac death). RESULTS: Living alone was an independent risk factor, with a hazard ratio of 1.54 (95% confidence interval, 1.04 to 2.29; P less than .03). Using the Kaplan-Meier statistical method for calculation, the recurrent cardiac event rate at 6 months was 15.8% in the group living alone vs 8.8% in the group not living alone. Risk remained significant throughout the follow-up period (P = .001). A disrupted marriage was not an independent risk factor. CONCLUSION: Living alone but not a disrupted marriage is an independent risk factor for prognosis after myocardial infarction when compared with all other known risk factors.

Adult↗
PubMedDate not supplied

Adenocarcinoma of minor salivary gland origin with skeletal metastasis in a child.

Primary epithelial neoplasms of the salivary gland in children are uncommon but are well recognized and occur principally in the major salivary glands. The purpose of this report is to document our experience with an adenocarcinoma of the buccal submucosa (one of several sites of minor salivary gland tissue) that metastasized to multiple bones as the initial sites of distant disease after a local recurrence. The clinical history, imaging studies, and microscopic sections including immunoperoxidase studies were evaluated from the primary tumor, local recurrence, and a metastatic lesion from the femur. The histopathologic features and immunohistochemical phenotype of the adenocarcinoma in the buccal submucosa supported its salivary gland origin. This case of adenocarcinoma of the intraoral buccal tissues independent of the parotid gland in a 12-year-old female is an unusual clinical presentation of a salivary gland neoplasm in childhood, and its ability to metastasize to distant skeletal sites is also remarkable in terms of a primary salivary gland carcinoma regardless of age at diagnosis.

Adenocarcinoma↗