Search PubMed⌕ Search

Biomedical subjects

R Nakamura

Publications and source records attributed to R Nakamura.

At least 451 records · Page 25Linked to original sources
PubMed1982

[Clinical study of preoperative chemotherapy of primary breast cancer. 1. Efficacy of a combined use of CPA (endoxan) and FT-207 (or 5-FU dry syrup)].

In twenty-nine cases of primary breast cancer preoperative treatment using CPA and FT-207 (or 5-FUDS) was performed to determine their efficacy. Daily dose of each anticancer drugs was as follows: CPA 50-200 mg, FT-207 200-600 mg, 5-FUDS 200 mg, p.o.. The total doses were CPA 1.8 g, FT-207 5.0g, 5-FUDS 3.4 g in average. In 11 cases (37.9%) reduction in tumor size was obtained. According to Ohboshi's criteria, over Grade II a effect was seen in 5 cases (17.2%), while Grade III effect was not seen in any of the cases. Effective cases were more frequently observed among those which received CPA at 25 mg/kg or more, or FT-207 (5-FUDS) at 80 mg/kg or more. Main side effects were G. I tract symptoms such as anorexia and nausea. To obtain definitive conclusion on the clinical significance of use of CPA and FT-207 (5-FUDS) as preoperative chemotherapy for breast cancer, further studies are required.

Adult↗
PubMed1982

Reaction time of elbow flexion during passive movements.

The effect of passive movements of the elbow on biceps EMG reaction time (RT) was studied in 10 normal subjects. Each subject was required to perform a simple RT task, flexing the left elbow to a tone stimulus, under three different conditions: (a) during passive flexion (PFLX) of the elbow, (b) during passive extension (PEXT), and (c) without passive movements (STAT). A forearm-rotator was used to produce a constant movement with angular velocity of 20 deg/sec, and in each condition the tone stimulus was always presented at the same angle of the elbow joint. Significant differences in mean EMG-RTs were found between the three conditions; the shortest EMG-RT of all was observed in the PFLX condition (77.0 +/- 15.0 msec), followed by that in STAT (93.1 +/- 11.8 msec) and lastly in PEXT (116 +/- 23.1 msec). Neurophysiological mechanisms underlying these phenomena are discussed.

Adult↗
PubMed1981

Fine structure of the central myelin sheath in the myelin deficient mutant Shiverer mouse, with special reference to the pattern of myelin formation by oligodendroglia.

The central myelin sheaths of the recessive autosomal mutant mouse, Shiverer, were investigated by electron microscopy with special reference to the pattern of myelin formation. The results obtained may be summarized as follows: (1) the major dense line of myelin lamellae generally failed to be formed, but the axons were enclosed by tri-lamellar structures of about 14 nm in width, which were composed of one central membrane formed by fusion of outer leaflets of adjacent cytoplasmic sheets of oligodendroglia, corresponding to the intraperiod line, and two outer membranes which were identical with inner leaflets of adjacent cytoplasmic sheets and became highly electron-dense. However, major dense lines were sporadically observed; (2) the myelin sheath was not generally formed by spiralling of one cytoplasmic process of the oligodendroglia, but by enclosing an axon with several stratified layers of cytoplasmic sheets, some of which were certainly formed by the splitting of one process; and (3) aberrant myelination frequently occurred around the soma of oligodendroglia, not related to any axons.

Animals↗
PubMed1981

I. Maternal cardiovascular and metabolic responses in normal pregnancy.

We investigated cardiovascular and metabolic responses in 23 healthy pregnant volunteers in their third trimester prior to, during, and after a 15-minute period of treadmill exercise. The energy utilization of this exercise was 2.33 MET with an oxygen consumption under 0.5 L/minute. Exercise induced a significant increase in maternal heart rate and a shortening of the R time intervals; both returned to baseline by 30 minutes of recovery. This light exercise also induced a significant increase in glucagon, norepinephrine, and epinephrine concentrations, all of which were transitory and reversed within 30 minutes of the recovery period. No change in glucose or cortisol concentration resulted from this exercise. We conclude that light exercise of brief duration elicits appropriate and transitory cardiovascular and metabolic responses in normal pregnancy.

Adult↗
PubMed1981

Effect of aging on single nephron renin content in rats.

To investigate the relation between renin content in each juxtaglomerular apparatus and reduction of plasma renin activity (PRA) with aging, the PRA and microdissected superficial or juxtamedullary single nephron renin content (SNRC) were determined in 5 young (3-6 months) and 5 aged (13-18 months) rats fed on a normal salt diet. The mean value of the PRA in the aged group was significantly lower than that of the young group. A highly significant correlation was found between the RPA and mean values of the superficial SNRC. The mean values of both the superficial and deep SNRC in the aged rats were significantly lower than those of the corresponding zones in the young rats. It is suggested that decreased synthesis of renin in each juxtaglomerular apparatus is an important factor in the decreased PRA observed with aging.

Aging↗
PubMed1981

Effect of angiotensin I converting enzyme inhibitor, SQ 14225, on renin production and release.

Renin production and release induced by angiotensin I converting enzyme inhibitor (CEI), SQ 14225, were studied in male Wistar rats. Acute studies on the effects of CEI (4.6 mumol/kg, i.m. every 6 h for 48 H) in rats revealed a significant reduction in angiotensin II levels and a marked increase in plasma renin activity (PRA). There were no appreciable changes in renal content (RRC) and the juxtaglomerular cell granulation index (JGI). In rats which had received CEI in their drinking water (0.92 mumol/ml) for 12 days, angiotensin II levels were decreased markedly and urinary excretion of sodium was increased, but the reduction in blood pressure was slight. PRA, JGI and RRC were markedly increased in these animals. The kidneys of CEI-treated rats exhibited conspicuous vascular dilatation. CEI treatment of sodium-depleted rats resulted in a reduction of the increased JGI and RRC and in a further increase in PRA. Our findings suggest that CEI administration may initially effect stimulation of renin release from the juxtaglomerular apparatus and that prolonged CEI administration results in a gradual stimulation of renin production.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1981

Effects of angiotensin II analog on blood pressure, renin and aldosterone in women on oral contraceptives and toxemia.

The role of the renin-angiotensin system in the development of hypertension was studied by infusing an angiotensin II analog, 1-Sar, 8-Ile angiotensin II, in women with toxemia and women on estrogen-containing oral contraceptives or estrogen treatment. In 3 of 4 women who developed hypertension on oral contraceptives or estrogen treatment, the blood pressure was reduced with the infusion of 1-Sar, 8-Ile angiotensin II. In 3 women who remained normotensive on oral contraceptives or estrogen treatment, the blood pressure was not reduced, although there was no significant difference in plasma renin activity (PRA) between the women who developed hypertension and those who remained normotensive on oral contraceptives. In 6 pregnant women who developed hypertension, the blood pressure increased remarkably with the infusion of 1-Sar, 8-Ile angiotensin II, although PRA was increased significantly in all of them. In these women, however, sodium excretion was less than that in normal pregnant women. In 4 normal pregnant women, the blood pressure remained unchanged or increased slightly, and PRA was almost similar to that of women who developed hypertension. The above results suggest that increased PRA in women who developed hypertension whilst on estrogen-containing oral contraceptives or estrogen treatment is more closely related to the development or maintenance of hypertension than that in pregnant women who develop hypertension, although there remains a possibility that the response of blood pressure to 1-Sar, 8-Ile angiotensin II in pregnant women who develop hypertension is influenced by sodium retention.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1981

Effects of branched chain fatty acids of iso-C12:0 to iso-C16:0 on gastric secretion and experimental ulceration in rats.

We examined the inhibitory activities of branched-chain fatty acids of iso-C12:0 to iso-C16:0 on gastric secretion in rats. Consequently, iso-C13:0 and iso-C15:0 were found to have strong inhibitory activities on gastric secretion in rats. In the case of intraduodenal administration, iso-C15:0 also showed a significant inhibition of gastric juice secretion. Therefore, the effects of iso-C13:0 and iso-C15:0 on ulceration in pylorus-ligated rats and aspirin-induced ulcer were examined. At the doses of 10 and 25 mg/kg, iso-C13:0 and iso-C15:0 significantly decreased the ulcer index in pylorus-ligated rats, and aspirin-induced ulcer was also significantly inhibited at the doses of 25 and 50 mg/kg. Finally, effect of iso-C15:0 on pepsin, Mg++-ATPase and carbonic anhydrase, which are considered to play an important role in the mechanism of gastric juice secretion, was examined in vitro, centering around iso-C15:0 which showed a marked effect in gastric juice secretion inhibitory and anti-ulcerogenic activities. Iso-C15:0 showed inhibitory activity on pepsin and Mg++-ATPase, but entirely no activity on inhibiting carbonic anhydrase.

Adenosine Triphosphatases↗
PubMed1981

Action of fragments of human parathyroid hormone on blood pressure in rats.

To investigate localization of the action on blood pressure in the peptide chain of parathyroid hormone (PTH), we determined the effect of seven fragments of human (h) PTH-(1-34) fragments on blood pressure in anesthetized rats. hPTH-(1-7) and -(28-34) fragments had no effect up to 1 X 10(-6) mole/kg. hPTH-(8-34), -(13-34), -(18-34), and -(23-34) fragments showed significant hypotensive activity. The decrease in the chain length lowered the hypotensive activity. The results indicate that some amino acids in position 23-34 are necessary for the hypotensive activity. This accords with the previous report suggesting that 5 amino acids in position 24-28 are essential. In addition hPTH-(8-34) and -(13-34) fragments showed initial transient hypertensive activities. hPTH-(1-13) fragment had only hypertensive action, suggesting that some amino acids in position 8-13 are necessary for hypertensive activity.

Animals↗