We have devised a bidirectional respiratory flowmeter using the hot-wire principle. The flow-direction sensor consists of a pair of tungsten wires strung parallel to the platinum hot-wire one on each side of the platinum wire. When the gas stream passes through the transducer, the upstream wire is cooled and the downstream wire is heated by the gas stream producing a temperature difference between the two tungsten wires. The difference in resistance thus produced between them is detected and amplified by a differential amplifier whose output serves as a triggering signal of flow inversion. The switching times of the flow inversion of the present instrument are 3 ms during panting and 10 ms during quiet breathing, when the distances from the platinum wire to the tungsten wires are 1.6 mm. Artifacts produced by the delay in switching are practically negligible. The flowmeter can be adapted for many kinds of respiratory flow measurement, except under the condition when inflammable gases are used.
Atherosclerosis is one of the diseases related to metabolic syndrome which is caused by obesity. Previous reports have shown that green tea and its components have anti-obesity effect. We examined whether catechins and caffeine can prevent the development of atherosclerosis by oral administration, singly or in combination to the atherosclerosis model mice. Results demonstrated that the number of atherosclerotic regions in the aorta was significantly reduced by the combined treatment, and the atherosclerotic area was also improved. Serum HDL-C increased by caffeine single treatment, but no effect on the TG and TC by any treatments. Moreover, ECG illuviated to atheromatous lesions in aorta and the illuviation was enhanced by caffeine. The mRNA expression levels of LOX-1 and TNF-α showed a tendency to suppress by the combined treatment. These results indicated that the combined administration of catechins and caffeine has the inhibitory effect on the development of atherosclerosis in mice.
The effects of the calcium entry blocker nicardipine on CBF, CMRO2, and neurologic outcome following 10 min of complete cerebral ischemia were examined in dogs. In CBF and CMRO2 studies, the CBF in the untreated group (seven dogs) and the nicardipine group (seven dogs; 20 micrograms kg-1 at 30 min postischemia and a subsequent infusion of 2 micrograms kg-1 min-1 for 90 min) initially increased to 300-400% and then returned to preischemic values at 30 min postischemia. Thereafter the CBF in the untreated group significantly decreased to 50% of preischemic values for the following 90-min period (hypoperfusion), while the CBF in the nicardipine group did not differ from preischemic values. The CMRO2 in both groups decreased to approximately 50-80% of preischemic values after 15 min postischemia and did not differ between the groups throughout the study. In neurologic outcome studies, 18 dogs were divided into three groups (of six dogs each): untreated; saline infusion only, posttreated; nicardipine as in CBF and CMRO2 studies, pretreated; nicardipine 20 micrograms kg-1 at 2 min preischemia and a subsequent infusion of 2 micrograms kg-1 min-1 from immediately postischemia to 120 min postischemia. Nicardipine treatment initiated either before or after ischemia failed to improve neurologic outcome at 48 h postischemia. Thus, the increase of postischemic global CBF by nicardipine is not accompanied by neurologic recovery in a canine model of complete cerebral ischemia.
The effects of lung traction on arterial blood pressure and plasma prostacyclin concentrations were studied in five patients undergoing partial pneumonectomy or lobectomy. After manual traction of a lung segment, mean arterial blood pressure decreased from 77 +/- 5 mm Hg (mean +/- SEM, before lung traction) to 59 +/- 5 mm Hg. The concentrations of 6-keto prostaglandin F1 alpha (a stable breakdown product of prostacyclin) increased significantly from 46 +/- 6 pg/mL (mean +/- SEM, before thoracotomy) to 593 +/- 91 pg/mL. Four of five patients showed facial flushing and palmar erythema. Arterial blood pressure returned to pretraction value, and both the facial flushing and palmar erythema disappeared within 30 min after lung traction. These results suggest that traction of the lung stimulates release and/or production of prostacyclin, which results in facial flushing, palmar erythema, and decrease in arterial blood pressure.
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