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Biomedical subjects

K Katayama

Publications and source records attributed to K Katayama.

At least 505 records · Page 28Linked to original sources
PubMed1981

Hypocalcemic effect of zinc and mechanism in rats.

The effect of zinc on serum calcium was investigated after a single oral administration of zinc sulfate in rats. Zinc (5, 10, and 20 mg Zn/100 g body weight) administration produced a significant decrease of serum calcium. This effect of zinc was not inhibited by thyroparathyroidectomy. Zinc administration resulted in a significant increase in calcium content of lungs and muscle but it was not significant in liver, kidneys, spleen and heart. Intestinal calcium absorption and bile calcium excretion was not affected by zinc administration. However, the urinary calcium excretion after zinc administration decreased markedly. On the other hand, zinc administration caused a remarkable elevation of calcium content in gastric secretion. This effect was dose-dependent (5 and 10 mg Zn/100 g). However, an increase in gastric calcium after zinc administration was completely prevented by atropine (0.1 micrograms/100 g) treatment, which also showed a marked inhibition of hypocalcemic effect of zinc. Meanwhile, acetylcholine (4.0 micrograms/100 g) administration caused a significant decrease of serum calcium by zinc administration is mainly based on an increase in gastric calcium secretion.

Acetylcholine↗
PubMed1981

[Left ventricular end-systolic pressure and wall thickness relation for the assessment of regional myocardial contractility in man (author's transl)].

In 28 patients (pts) (5 normal subjects (N), 12 pts with valvular heart disease, 6 with cardiomyopathy, and 5 with ischemic heart disease), left ventricular (LV) pressure was measured using Millar's catheter tip transducer simultaneously with LV posterior wall thickness (W) by echocardiography. After the control recording, LV peak systolic pressure was altered by about 30 mmHg from the control level by angiotensin (20 ng/kg/min) or nitroprusside (1 gamma/kg/min) to attain two (18 pts) or three (10 pts) different end-systolic pressure points, determined after the steady state was achieved. LV end-systolic pressure and wall thickness (P-W) relation a the three different end-systolic pressure points was found to be linear (r = 0.996) in each of the 10 pts, suggesting that end-systolic P-W relation is independent of afterload. Isoproterenol infused in 4 pts, which led to an increase in peak positive (+) dp/dt by a mean of 28%, increased the slope of the P-W relation by 43.4% of the control value (P less than 0.001), while propranolol, which led to a decrease in peak (+) dp/dt by a mean of 16.7%, reduced the slope by 27.3% (p less than 0.001). This indicates the sensitiveness of the slope of P-W relation to the inotropic change of the myocardium. In N, the slope of the P-W relation was -29.7 +/0 6.0 mmHg/mm (mean +/- SD), while the value in 4 pts with decreased functional capacity (NYHA III or IV) was significantly lower (-13.7 +/- 2.9 mmHg/mm; p less than 0.001). Thus, the present study suggests that the slope of the end-systolic P-W relation is useful in assessing regional myocardial contractility in man.

Adult↗
PubMed1980

Inhibitory effect of progesterone on follicular growth and induced superovulation in the rat.

We investigated the effect of exogenous progesterone on follicular growth and pregnant mares' serum gonadotropin and human chorionic gonadotropin (PMS-HCG) induced superovulation in intact and hypophysectomized immature rats. Although the administration of progesterone during PMS-HCG injections had no effect on superovulation, the administration of progesterone beginning 3 days before PMS injection inhibited superovulation in both intact and hypophysectomized rats. In order to study the mechanism of inhibition of superovulation by pretreatment with progesterone, an autoradiographic study using tritiated thymidine was done in hypophysectomized rats just before PMS injection. The labelling indices of granulosa cells were significantly decreased by the administration of progesterone (p < 0.001). Treatment with progesterone resulted in an increase of the follicles in early stages of atresia with pycnotic nuclei in granulosa cells surrounding apparently normal oocytes. Ovarian histology and serum and ovarian tissue concentrations of estradiol were then examined in hypophysectomized rats 20 h after HCG injection. Large Graafian follicles and corpora lutea were rarely seen in rats previously given progesterone, whereas many large Graafian follicles and corpora lutea were observed in the control rats. The concentrations of estradiol in the progesterone-pretreated rats were significantly reduced in serum (p < 0.02) and slightly reduced in ovarian tissues when compared with controls.

Animals↗
PubMed1980

Effects of a new adenosine deaminase inhibitor, isocoformycin, on toxicity, antitumor activity and tissue distribution of formycin A and 9-beta-D-arabinofuranosyladenine.

Single intraperitoneal and intravenous injections of isocoformycin at 1,200 mg/kg did not cause the death of mice. Isocoformycin which inhibited adenosine deaminase enhanced significantly the toxicity of formycin A and ara-A at various combination ratios. Isocoformycin potentiated antitumor activity of formycin A and ara-A against L1210 leukemia. Formycin A and ara-A disappeared rapidly from the blood and tissues and could not be found in any tissues even 0.5 hour after a single intraperitoneal injection. However, when used in combination with isocoformycin both were detected in the blood and tissues, especially at high concentration in liver and kidney. These indicate that the deamination of formycin A and ara-A is blocked by isocoformycin in vivo.

Adenosine Deaminase Inhibitors↗
PubMed1979

Clinical evaluation of thyroid CT values in various thyroid conditions.

CT scans of the thyroid were performed with a Hitachi CT-W2 device. The CT value of the region of interest (ROI) was obtained from CT images of the thyroid. Mean and standard deviation was 112 +/- 10 in 44 normals. Out of 27 cases of hyperthyroidism, the CT value of 13 untreated cases of 58 +/- 4, and that of 13 cases under treatment was 73 +/- 7 in average. The CT value of the single cured case was 100. Twelve cases of chronic thyroiditis and 5 cases of hypothyroidism showed averages of 57 +/- 11 and 36 +/- 13, respectively. The results of the above-mentioned clinical study indicate the estimation of the CT value of the thyroid is useful for diagnosis of various thyroid conditions.

Humans↗