[Hokkaido igaku zasshi] The Hokkaido journal of medical science
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Hokkaido Igaku Zasshi · Sep 1994
[Pharmacological studies on alterations in myocardial beta-adrenoceptors and their intracellular signal transduction in experimental diabetic rats].
The present study was undertaken to determine abnormalities which are responsible for the diminished functional responsiveness to beta-adrenoceptor stimulation in experimental diabetic rats. Rats were given an intravenous injection of 45mg/kg streptozotocin and hearts were removed from 4 to 6 weeks later. The positive inotropic effects of isoproterenol, norepinephrine and epinephrine were markedly depressed in diabetic rat papillary muscles. ⋯ To test this hypothesis, incorporation of [32P]-inorganic phosphate into phospholamban in sarcoplasmic reticulum was examined in Langendorff-perfused hearts. Isoproterenol (100nM) increased phosphorylation of phospholamban threefold in control hearts, but did not cause a significant change in the phosphorylation state in diabetic hearts. From these findings it is concluded that the decreased functional responses to cyclic AMP-increasing agents like beta-adrenoceptor agonists in diabetic hearts may be associated with impaired phosphorylation of cardiac regulatory phosphoproteins including phospholamban.
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Hokkaido Igaku Zasshi · May 1994
Rapid inhalation induction with high concentration of sevoflurane using a new vaporizer.
Sevoflurane allows a moderately rapid induction with only slight problems of induction. However, it has not been possible to conduct tests with more than 2.6 minimum alveolar concentration (MAC) of sevoflurane (4.5%) because of the limitations in the performance of the currently available vaporizer. We tested the performance of a new vaporizer and tried it with single breath induction. ⋯ Although coughing was observed in two subjects, laryngospasm, breath holding, and secretions did not occur during induction by this method. All subjects except one would be willing to undergo similar induction again. This study demonstrate that the new vaporizer can be used to administer 7.5% concentration of sevoflurane and to adequately perform smooth and rapid inhalation induction of anesthesia in young volunteers without premedication.
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Hokkaido Igaku Zasshi · Mar 1994
[Effects of megadose methylprednisolone therapy on acute spinal cord injury in rats].
Present study was performed to confirm the protective effect of megadose methylprednisolone therapy for the posttraumatic spinal cord ischemia. Seventeen Wistar-King rats weighing 215-330 g were divided into four groups which were normal group (n = 5), injury group treated by saline (control group, n = 4), treated by methylprednisolone (MP) 30 mg/kg (n = 4) and treated by MP 60 mg/kg (n = 4). Animals were anesthetized aspirating 1.5% Halothane and made epidural clipping injury (140 g for 3 seconds) at Th7/8 after laminectomy of Th7,8. ⋯ SCBF of the white matter adjacent to the injury site was not decreased, but preserved within normal range or rather slightly hyperemic. These condition may cause the secondary damage in the adjacent spinal cord. It is considered that megadose of methylprednisolone, if it is effective for the spinal cord injury, would suppress the SCBF of white matter of adjacent to the injury site at the acute phase and prevent the progression of secondary damage.
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Hokkaido Igaku Zasshi · Sep 1993
[Effects of acidosis on the neuronal function following oxygen-glucose deprivation in the rat hippocampal slices].
This study was designed to examine 1) whether cerebral ischemic damage is aggravated by accompanying acidosis and 2) which has more potential to cause neural damage between respiratory and metabolic acidosis. To investigate these points, inhibition and recovery of hippocampal evoked potentials were studied in vitro with different pH solutions. Population spike (PS) activity was recorded from CA 1 region after stimulation of the Schaffer collaterals of the 400 microns hippocampal slices from young Wister rats. ⋯ By addition of CO2, the recovery of PS following OGD was inhibited to a similar degree as with 30 mM lactic acidosis. It is concluded that concomitant acidosis has divergent effects on the cerebral ischemic damage depending on the pH; mild acidosis had a protective effect but profound acidosis had an aggravating effect, the cross over point being at around pH 6.0. Lactate and CO2 potentiated the aggravating effects of acidosis even though the extracellular pH remained the same.
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Hokkaido Igaku Zasshi · Jul 1993
Randomized Controlled Trial Clinical Trial[Behavioral control of breathing and the effect of endogenous opiates in chronic obstructive pulmonary disease].
Dyspnea is a common symptom in patients with chronic obstructive pulmonary disease (COPD) but its mechanism is unclear. It is known that the opiate antagonist, naloxone, restores in some patients with COPD the ability to compensate for a flow-resistive load (N Engl J Med 1981; 304; 1190-5). We studied the effect of naloxone on the threshold of resistive load detection (RLD) and on sensation of breathlessness in patient with COPD. ⋯ P: 0.89 +/- 0.44 during P vs 0.97 +/- 0.54 during NLX, NS. Gf/VE: 0.76 +/- 0.57 during P vs 1.38 +/- 0.62 during NLX, P < 0.01). FRC, VE, f, T1, TE and P0.1 did not significantly change after NLX.(ABSTRACT TRUNCATED AT 250 WORDS)