Biomedical subjects
Publications and source records attributed to H Samnegård.
Somatostatin, 0.2-1.0 microgram . kg-1 . min-1, was administered i.v. in 5 anesthetized dogs. Following 9-min infusions, hepatic bile output was found to decrease by approximately 50% after a latency of 6 min. The mode of action suggests that somatostatin inhibits hormone-induced bile output.
Circulatory effects of gastrointestinal hormones and related peptides are surveyed. Only experiments using low peptide dosages, non-extensive surgery and intravenous infusions give relevant data in this field. Glucagon, secretin, vasoactive intestinal peptide, gastrin, cholecystokinin, Substance P and Somatostatin are vasoactive within the splanchnic area, each fraction in a specific pattern.
The effect of intravenous administration of 0.3 g of Xantinoli nicotans (Complamin) and 40 mg of papaverine on internal carotid artery (ICA) blood flow in 17 conscious, newly operated patients was studied with the aid of electromagnetic flowmetry. A flow probe was attached to the ICA after carotid reconstruction. Administration of Complamin resulted in a significant decrease in arterial mean pressure and a corresponding decrease in ICA flow. The arterial mean pressure also diminished after administration of papaverine, but the decrease was moderate and did not influence ICA flow. The results indicate that the cerebral vascular autoregulation may be impaired in the early postoperative period. Vasoactive substances, which cause decreased arterial pressure, also influence ICA flow and should be avoided in patients newly operated upon for occlusive disease of the carotid artery.
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The effect of physical exercise on internal carotid artery (ICA) blood flow in conscious man was studied with the aid of electromagnetic flowmetry. A flow probe was implanted on the ICA in 25 patients after reconstruction of the artery. ICA mean blood flow and brachial artery mean blood pressure were continuously monitored in supine (25 patients) and sitting (24 patients) position at rest, during 5-6 minutes exercise on a bicycle ergometer and at rest after exercise. Arterial carbon dioxide tension (PaCO2) was studied in 6/25 work tests in supine and 7/24 in sitting position. Cardiac output was measured at rest and during exercise in 10/25 patients in supine and 8/24 patients in sitting position. In the supine group, ICA flow increased significantly within 1 minute and reached a maximal flow 15% above control flow within 2 minutes after the onset of exercise. The ICA flow then gradually declined, but remained almost significantly elevated, 7.5% above control, on termination of exercise. At rest, after exercise, the ICA flow decreased almost significantly to a level of 5% below the control flow within 5 minutes. There was a significant PaCO2 increase of 2.6 mmHg during exercise and a highly significant increase (72%) in cardiac output during exercise. The ICA flow at rest, before exercise, was about 15% lower in the sitting group than in the supine group. It increased in average 11.5% with 2 minutes of exercise and then gradually diminished. At rest, after exercise, ICA flow decreased further to a level of 8% below control flow within 5 minutes. PaCO2 increased significantly in average 1.6 mmHg during exercise. Cardiac output increased highly significantly (85%) during exercise. The ICA flow changes obtained during exercise in the present study indicate the presence of a regulatory mechanism counteracting the increasing perfusion pressure, but it is unable to compensate the decreased perfusion pressure when the body position was altered from supine to sitting. The cerebral vascular bed in the present patient material seems to operate above and below the lower limit of its pressure range for an adequate autoregulation.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.