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K Numazawa

Publications and source records attributed to K Numazawa.

6 recordsLinked to original sources
PubMed1994

[A study on the interstitial level of endogenous adenosine and its cardioprotective effect during ischemia/reperfusion in the canine heart].

The role of endogenous adenosine on the functional recovery of the heart reversibly injured by ischemia/reperfusion (stunned myocardium) was studied in in vivo canine hearts. Anesthetized open-chest dogs (n = 37) were subjected to 15-min left anterior descending artery (LAD) occlusion followed by 60-min reperfusion. Group 1 (n = 13) received saline and group 3 (n = 9) received an adenosine potentiator, dipyridamole (20 micrograms/kg/min, i.v.), from 15 min before LAD occlusion for 45 min. Group 2 (n = 8) and group 4 (n = 7) were pretreated with an adenosine blocker, 8-phenyltheophilline (8-PT; 10 mg/kg, i.v.), before the saline or dipyridamole infusion, respectively. Interstitial levels of adenosine and its metabolites were measured using cardiac microdialysis technique. Regional cardiac function in the ischemic area was assessed by segment shortening (%SS) with ultrasonic crystals. The dialysate concentration of adenosine in the ischemic region increased from 0.32 to 1.90 microM by the 15-min LAD occlusion in group 1. Dipyridamole enhanced this increase in adenosine to 5.51 microM, with a significant improvement of %SS (36.8 vs. 61.0% at 60 min after reperfusion in group 1 and group 3, respectively; each preischemic level: 100%). Pretreatment with 8-PT did not modify the change of adenosine level in groups 2 and 4, however, significantly deteriorated %SS compared with groups 1 and 3, respectively. Hemodynamic parameters were not statistically different among 4 groups throughout the experiment. Thus, endogenous adenosine was clearly demonstrated to protect stunned myocardium against ischemia/reperfusion. The enhancement of cardiac interstitial level of adenosine with adenosine potentiators, such as dipyridamole, may be expected to ameliorate cardiac function during coronary recanalization therapy or cardiac surgery.

Adenosine↗
PubMed1993

[Effects of intravenous injection of ioversol, a nonionic contrast medium, on circulating blood volume: comparison among different combinations of its dose and volume injected].

Effects on circulating blood volume (CBV) of the intravenous injection of a nonionic contrast medium, ioversol, with various doses were assessed in order to find a way of injection with less effects on systemic circulation. Ioversol was injected as a bolus to 20 mongrel dogs at doses of A: 3.75 ml/kg (n = 8) or B: 2 ml/kg (n = 6) of a solution containing 320 mg iodine per ml, or C: 2 ml/kg (n = 6) of a 240 mgI/ml solution. Colloid oncotic pressure (COP) of the bloods drawn before and 1, 2, 3, 5 min after the injection of ioversol was measured by a needle type osmometer, and changes in CBV were calculated using the COP values. Upon injection of ioversol CBV increased rapidly and then gradually returned to the preinjection levels. The change in CBV induced by ioversol was significantly less than those reportedly induced by an ionic contrant medium, iothalamate, and a nonionic medium, iopamidol, and comparable to that by another nonionic medium, iohexol. The degree of increase in CBV and the blood concentration of ioversol were related to the amount, but not the volume, of ioversol injected. Thus, ioversol proved to be one of the low osmotic nonionic contrast media with less effects on CBV. Furthermore, it is suggested that the amount, rather than volume, of contrast medium should be taken into consideration when the angiography of the patients with reduced cardiac function, children or aged patients is performed in whom the contrast medium-induced CBV expansion needs to be as less as possible.

Animals↗
PubMed1987

[A case of carcinoma in situ of the renal pelvis].

A case of carcinoma in situ of the renal pelvis in a 70-year-old female is reported. The patient was admitted with the complaints of macrohematuria and left back pain. Urine cytology, which was carried out three times using urine samples collected directly from the urinary bladder proved to be negative. Drip infusion pyelography (DIP) and retrograde pyelography (RP) disclosed stenosis of the left ureter at the level of L3-L4. Selective renal angiography revealed no abnormalities. Based on the DIP and RP findings, the diagnosis of tumor in the left ureter was made, and left total nephroureterectomy with partial cystectomy was performed. The removed kidney showed signs of mild hydronephrosis but no tumor was found macroscopically. The stenosed site of the ureter had scar-like tissue. Microscopic examination revealed that the stenosed ureter consisted of nonspecific granulation tissue but the mucosa of the renal pelvis showed grade III transitional epithelial cell carcinoma, At 24 months after operation, there is no evidence of tumor recurrence, and urine cytology is also negative.

Aged↗
PubMed1980

Normotensive primary aldosteronism.

A very unusual case of normotensive primary aldosteronism is described. A 25 year old woman first noticed numbness of both hands followed by a typical tetany attack. The blood pressure was within normal ranges. The results of other physical examinations were negative except for the findings of Trousseau's sign. Hypokalemi, increased potassium clearance, disturbed urine concentration and increased circulating plasma volume were noticeable. Diagnosis was established by (1) increased levels of plasma aldosterone, (2) low plasma renin activity, (3) normal adrenocortical function and (4) typical aldosterone-producing adenoma. After removal of the adenoma, the abnormalities subsided. The lack of hypertension in primary aldosteronism is a rare condition. Several possible causes of normotension must be considered, such as the early phase of primary aldosteronism, essential hypotension associated with primary aldosteronism and lack of concomitant secretion of other mineralocorticoids from the adenoma, but these were all negligible. As blood pressure response to the administration of angiotensin II was lower than is typical for primary aldosteronism, and the patient transiently suffered from frequent attacks of blackouts soon after the operation, the cause of normotension was thought to be due to the existence of a hypotensive mechanism which counteracts the increase in blood pressure in primary aldosteronism.

Adenoma↗