Clinical science and molecular medicine. Supplement最新文献

1. Mucociliary clearance has been measured over a 6 h period by using the radioaerosol technique in seven normal male subjects lying supine, both during the day when awake, and during the night when asleep. 2. The percentage of radioaerosol cleared during the night, when asleep, was significantly less than during the day when awake (P less than 0.02). 3. A comparison of radioaerosol clearance before and after the time of onset of sleep demonstrates that reduced clearance occurred during sleep, indicating that this is probably a sleep-related phenomenon and not merely a result of diurnal variation. 4. This finding has important implications for patients with chronic bronchitis or asthma, in whom early morning cough or wheeze may be a predominant feature.

1. The response of active and inactive plasma renin to orthostasis and frusemide and to inhibition of prostaglandin synthesis by indomethacin was tested in normal human volunteers. 2. Active renin increased by orthostasis and frusemide and decreased by indomethacin. The latter also blunted the increase of active renin after stimuli. 3. Inactive renin was slightly increased by orthostasis, but was not significantly influenced by acute administration of frusemide or inhibition of prostaglandin synthesis by indomethacin. 4. The results show differences in the response of active and inactive renin to stimuli and suppression. Opposite changes of active and inactive renin were not observed in the experimental conditions studied.

1. Anaesthetized cats were subjected to two 10 min trials of head-up tilting spaced 30 min. Arterial pressure, heart rate, blood flow to an innervated kidney and to the contralateral denervated one, and renin release from both kidneys were measured. 2. The same haemodynamic changes and comparable increases in renin release from innervated kidneys occurred during both episodes of tilting when cats were subjected to sham cervical vagotomy between the two tilting trials. 3. Bilateral cervical vagotomy, performed after the first episode of head-up tilting, did not affect the haemodynamic response to the change in posture, but significantly and markedly reduced the increase in renin release from the innervated kidney. 4. After sino-aortic denervation a marked and sustained arterial hypotension occurred during tilting, and the postural increase in renin release from the innervated kidney was even greater. 5. In no condition, even during the marked fall in blood pressure in sino-aortic denervated cats, did head-up tilting increase renin release from the denervated kidney. 6. It is concluded that maintenance of arterial pressure during tilting is mainly due to sino-aortic reflexes, whereas vagal reflexes are mostly responsible for the postural increase in renin release.

1. Average supine circulating total catecholamine concentrations were found to be higher than the normal range in about 50% of patients with labile hypertension and in about 30% of patients with sustained essential hypertension. 2. These higher resting concentrations were mainly due to an increase in adrenaline in labile hypertension and to an increase in noradrenaline in sustained hypertension. 3. Patients with elevated catecholamine concentrations were also characterized by a higher heart rate, by an increased myocardial contractility and by greater hypotensive response after treatment with beta-adrenoreceptor blocking agents. 4. These studies suggest the existence of sub-groups of hypertensive patients with increased sympathetic tone.

1. Baroreflex sensitivity was tested in three normal, three borderline and one hypertensive subject before and during mental arithmetic, the prolongation of pulse interval caused by a provoked rise in blood pressure being used as a measure of baroreflex sensitivity. 2. Baroreflex sensitivity was significantly decreased during mental arithmetic. 3. During mental arithmetic the arterial pressure fluctuated markedly. 4. These findings suggest that in man, as well as animals, the defence of alerting reaction depresses baroreflex control and thus contributes to the rise in blood pressure seen at this time.

1. We have recorded ambulant intra-arterial blood pressure in five normo- and 14 hyper-tensive subjects over 24 h, particular attention being paid to the time of arousal. 2. The data were edited beat-by-beat before storing systolic, diastolic, and mean blood pressure +/- SD for every 2 min period on a computer file. 3. When pooled hourly mean data are plotted there is a rise of 52.9 mmHg systolic and 22.3 mmHg diastolic pressure from 03.00 hours to 11.00 hours in the 14 hypertensive subjects. 4. When the data are plotted in 20 min periods for the hours before and after arousal it is clear that the major rise in pressure occurs abruptly at that time. The 2 h period before arousal shows only a small rise in pressure, i.e. 6.9 mmHg systolic and 2.9 mmHg diastolic. 5. It is suggested that the apparent rapid early morning rise of blood pressure is an artifact of the method of analysis.

1. The role of vasopressin in blood pressure control and in the pathogenesis of one-kidney Goldblatt hypertension in the conscious dog was investigated. 2. Infusion of synthetic arginine vasopressin to elevate plasma levels approximately five-fold caused bradycardia in normal dogs and increase in mean arterial blood pressure in dogs with pharmacological autonomic blockade. 3. A similar degree of elevation of plasma vasopressin concentration was observed after mild non-hypotensive haemorrhage. 4. Renal artery constriction in unilaterally-nephrectomized dogs caused a rise in plasma renin activity and only a doubling of plasma vasopressin concentration, but a marked rise in mean arterial blood pressure. 5. Vasopressin may play a role in normal cardiovascular homeostatic responses, but its role in the pathogenesis of this form of hypertension is unlikely to be significant.

1. Variables involved in the genesis of hypertension in male broad-breasted white turkeys include social environment, obesity and high salt intake. 2. The hypertension is characterized by low plasma renin activity and, with increasing age, normal to high plasma aldosterone. 3. Medionecrosis of the abdominal aorta is a common pathological finding. 4. The absence of atherosclerotic plaques is probably related to the high concentrations of alpha-lipoproteins.