Physiological research
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Physiological research · Jan 1996
Laryngeal patency and expiration reflex following focal cold block of the medulla in the cat.
The involvement of the intermediate area and Bötzinger complex (BOT) of the rostral ventral respiratory group (r-VRG) in laryngeal control and generation of the expiration reflex were studied in anaesthetized non-paralyzed cats Focal cooling (to 20 degrees C) of the nucleus paraambigualis (NPA) caused changes in the frequency and timing of breathing with the concomitant rise in laryngeal resistance. Cooling of the nucleus ambiguus resulted in a consistent drop in laryngeal resistance. ⋯ The expiration reflex was inhibited by cooling of either the NPA or BOT. The role of these medullary regions in the control of laryngeal patency and central integration of the expiration reflex is discussed.
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Physiological research · Jan 1995
The effect of combination therapy with cyclosporine A and hydrocortisone on glucose metabolism in diabetic rats following pancreatic islet transplantation.
Glucose tolerance, insulin secretion and in vitro insulin action were examined in streptozotocin-induced diabetic rats following pancreatic islet allotransplantation treated with combination of oral cyclosporine A (10 mg/kg) and hydrocortisone (1.5 mg/kg) intramuscularly. 1400 pure islets from multiple donors were implanted either into the portal vein (n = 10) or under the renal capsule (n = 11). Ten sham-operated non-diabetic animals receiving the same immunosuppressive therapy, 8 healthy animals without any treatment and 10 diabetic animals without immunosuppression following islet transplantation were used as controls. In all transplanted animals blood glucose was normalized by day 3 after transplantation with lower levels in those transplanted intraportally (p < 0.05). ⋯ In vitro insulin action determined by the incorporation of labelled glucose into adipose tissue was impaired only in animals in which islets were transplanted into the liver (p < 0.05 vs other groups). In conclusion, therapy with cyclosporine A and hydrocortisone prevents allogeneic islet rejection in rats during a short-term experiment. Although glucose tolerance is not completely normalized following transplantation, slight impairment is also demonstrable in healthy animals on the same drug therapy.
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Physiological research · Jan 1992
Heart rate and arterial pressure variability in humans during different orthostatic load.
The influence of posture on the rhythms in blood pressure, heart rate and respiration was tested by means of spectral analysis in 14 healthy subjects. During squatting, standing and sitting, the finger blood pressure was recorded by the non-invasive Penáz technique together with cardiac intervals and respiratory movements. The power spectra obtained from five-minute samples showed that the respiratory components of cardiac interval and pulse pressure were reduced significantly in standing. Compared to squatting, a significant increase of total power in the medium frequency band (0.05-0.15 Hz) for cardiac interval, diastolic and mean pressure could be detected.