Derek B. Frewin

Vascular responses in the hands of Parkinson's disease patients

The response of oral temperature and hand heat elimination to the placement of one arm in a water bath at 44°C was studied in normal women of different ages and in parkinsonian patients with or without levodopa therapy. The patients, whether or not receiving medication, had very low heat eliminations compared with the controls. In two patients with unilateral disease, the vascular responses in the affected hand were reduced in comparison with those in the unaffected side. These findings suggest that there is an abnormality of vascular control in Parkinsons disease caused by autonomic dysfunction, either in the central nervous system or efferent sympathetic pathways.

Dopamine-β-hydroxylase activity in plasma obtained from the pulmonary artery and left ventricle of man

Abstract Dopamine-β-hydroxylase activity (DBH) has been measured in plasma obtained simultaneously from the pulmonary artery and left ventricle of fourteen patients who underwent diagnostic cardiac catheterisation. In the majority of these subjects the levels of enzyme activity in the arterial and venous blood were similar, indicating that inactivation of DBH had not occurred in its passage through the pulmonary circulation. One patient with pulmonary hypertension had a large a-v difference in enzyme activity that may have been caused by altered pulmonary haemodynamics. Three of the five subjects that undertook a standardised exercise test on a bicycle ergometer showed a significant increase in plasma DBH activity. There was no correlation between the increases in DBH activity and in cardiac index and heart rate.

A Comparison of the Efficacy of Captopril and Enalapril Given Once Daily for the Treatment of Hypertension: A Study Using 24-Hour Ambulatory Blood Pressure Monitoring

Sixteen patients who had essential hypertension were stabilized on either captopril or enalapril monotherapy and had 24‐hour blood pressure profiles monitored by using one of two automatic, non‐invasive ambulatory systems: Spacelabs 5300 (Squibb, Princeton, NJ) or PAR Physioport II (Kardiotec, Mannheim). In four subjects (group 1), ambulatory pressures were repeated 4 to 6 weeks later using the same equipment and the same drug. In four subjects (group 2), the drug was changed (dose ratio: captopril:enalapril, 5:1) after the first measurement, but the monitoring equipment was not changed. In four subjects (group 3), the drug was constant, but the equipment was changed for the second measurement of ambulatory pressure. In four subjects (group 4), both drug and equipment were reversed after the first measurement. The results showed that both drugs (given once daily) controlled blood pressure during the 24‐hour period, with no clinically significant difference between them.