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Biomedical subjects

A Murray

Publications and source records attributed to A Murray.

At least 397 records · Page 22Linked to original sources
PubMed1977

Peripheral and autonomic nerve function in newly diagnosed diabetes mellitus.

Peripheral and autonomic nerve function was assessed in 10 newly diagnosed male diabetics (six insulin-treated and four sulfonylurea-treated) with repeated observations over the subsequent six months. There was significant impairment of motor-conduction velocity in the common peroneal nerve at diagnosis in both treatment groups, with improvement following treatment in only the insulin-treated patients. In contrast, although the blood glucose level fell in both groups, the mean level was significantly lower in the sulfonylurea-treated patients at two months and at each subsequent visit. In the autonomic function tests significant abnormality was found in the electrocardiographic R-R-interval (beat-to-beat) variation in resting heart rate in two of the insulin-treated patients and all of the sulfonylurea-treated group, with improvement in only one of the latter. One patient in the sulfonylurea-treated group also showed an abnormal response to the Valsalva maneuver (expressed as the Valsalva ratio), and this remained abnormal throughout the period of study. All other patients had normal responses to the Valsalva maneuver and sustained handgrip test. None of the patients had postural hypotension. Abnormalities in autonomic nerve function in diabetics at diagnosis have not been previously reported.

Adolescent↗
PubMed1977

Electron microscopic detection of phleomycin during different waves of replication in regenerating skeletal muscle of mice following staining with mercuric chloride.

Phleomycin has devastating effects on regeneration of skeletal muscle when applied during an early wave of replication in the pre-myotube (new fibre) period of the reaction. The effect cannot be explained from the contribution of dividing cells to myotubes. Phleomycin's effects on regeneration are much less severe when the challenge coincides with a later wave of pre-myotube proliferation, effects that can be explained from the contribution of such cells to new muscle. An attempt has been made, by means of electron microscopy, to explain how phleomycin distributes early versus late wave cells, using a mercury substitution stain to detect the antibiotic. Cells of the two periods showed conspicuous differences in the staining characteristics of their chromatin. Positive staining reactions outside the nucleus were confined mainly to ribosomes. Exceptions included materials in transit across nuclear and cytoplasmic membranes.

Animals↗
PubMed1976

[Frequency and prevention of ventricular arrhythmias after acute myocardial infarct].

In a controlled study using mexiletine and placebo, the incidence of ventricular arrhythmias after acute myocardial infarction (AMI) has been compared. The study covered 40 male patients who had sustained AMI and who in the first 48 h after onset of infarction had exhibited ventricular tachycardia, R on T-, multiform or close-coupled ventricular ectopic beats. Half of the patients were given either mexiletine (250 mg 8-hourly) or placebo. On the 4th and 10th day after onset of infarction a continuous 24-hour ECG was performed. 76% of the patients receiving placebo showed serious ventricular arrhythmias compared with 32% receiving mexiletine (p less than 0.05). These results demonstrate (1) the frequency of ventricular arrhythmias in a group of patients already at risk, and (2) the efficacy of an oral antiarrhythmic agent like mexiletine in the management of these rhythm disorders.

Arrhythmias, Cardiac↗
PubMed1976

Peripheral and autonomic nerve function in diabetic ketoacidosis.

Peripheral and autonomic nerve function was assessed at intervals over a 3-month period in seven diabetics after ketoacidosis. There was marked improvement in motor conduction velocity and terminal latency of both ulnar and common peroneal nerves in all patients. Five had one or more abnormal autonomic function tests but there were no consistent changes during the same period. It is postulated that peripheral nerves may be more susceptible to acute metabolic damage than autonomic fibres.

Adolescent↗
PubMed1976

Interaction between cardiovascular responses to sustained handgrip and Valsalva manoeuvre.

Interactions between the cardiovascular responses to the Valsalva manoeuvre and sustained handgrip were analysed in 5 men with untreated mild hypertension and 4 young normal subjects. Though set at a higher level, there was a normal blood pressure response to the Valsalva manoeuvre during concurrent sustained handgrip in 4 of the 5 hypertensive subjects. At the end of the handgrip period in which the Valsalva manoeuvres were performed, the blood pressure was higher and the heart rate lower than in the control period of sustained handgrip. The fifth subject developed a 'square wave' Valsalva response, which returned to a normal response when sustained handgrip was discontinued. Analysis of RR interval changes in the normal subjects showed that both the tachycardia during, and the bradycardia after, the Valsalva strain period were significantly reduced during simultaneous sustained handgrip. These results show that the two reflexes interact, but only to a minor extent, and that the baroreflex response is modified by sustained handgrip, rather than overridden as had previously been suggested. In view of the effect on the blood pressure and heart rate, subjects should avoid performing a Valsalva manoeuvre during sustained handgrip testing.

Adult↗
PubMed1976

A day school approach to aggressive adolescents.

A day school for aggressive adolescents, organized cooperatively by a school system, a youth guidance center, and a state hospital, is providing an effective alternative to institutionalization. Education and therapy are combined in a supportive setting.

Adolescent↗
PubMed1975

Comparison of procainamide and mexiletine in prevention of ventricular arrhythmias after acute myocardial infarction.

The incidence of ventricular arrhythmias after myocardial infarction has been compared in a controlled study of procainamide, mexiletine, and placebo. Sixty male patients who has sustained a myocardial infarction and had received lignocaine for ventricular tachycardia or ventricular ectopic beats which were R-on-T, multiform, or close-coupled took part. The efficacy of the drugs was evaluated by continuous 24-hour recordings of the electrocardiogram on the 4th and 10th days after admission to the study. Procainamide was given as 500 mg. 4-hourly and mexiletine as 250 mg. 8-hourly with corresponding placebo regimens for 12 days. 77% of patients receiving placebo showed serious ventricular rhythm disorders compared with 33% receiving antiarrhythmic therapy (p smaller than 0.05). Although only 35% of patients receiving procainamide achieved accepted therapeutic plasma concentrations compared with 95% of those receiving mexiletine, both drugs were equally effective antiarrhythmically. The only major adverse effect of therapy noted was development of a positive antinuclear factor in a procainamide-treated patient. These results demonstrate the efficacy of oral antiarrhythmic agents in the management of ventricular arrhythmias after acute myocardial infarction. Mexiletine has the advantage of less frequent administration and lower toxicity.

Administration, Oral↗
PubMed1975

Letter: safe sport.

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Coronary Disease↗
PubMed1975

RR interval variations in young male diabetics.

The beat-to-beat (RR interval) variation in resting heart rate was used to detect possible autonomic nerve damage in a group of 42 young asymptomatic male diabetics, employing a sensitive electrocardiographic computer technique. Compared with 25 age-matched controls, the diabetics showed both a significantly smaller mean RR interval (P less than 0.005) and less RR interval variation (P less than 0.001). Whereas only 4 of the diabetic subjects had shorter mean RR intervals, 22 (52%) of the diabetics had RR interval variations that were less than any of the normal subjects. This reduction in heart rate variation has not been previously reported in diabetics without clinical features of autonomic neuropathy and might provide a sensitive method of assessing early autonomic nerve involvement in diabetes.

Adult↗