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Biomedical subjects

T Iwata

Publications and source records attributed to T Iwata.

At least 343 records · Page 19Linked to original sources
PubMed1985

Morphologic study of three cases of insulinoma. Histochemical and ultrastructural studies.

Ultrastructural and immunocytochemical features of three human insulinomas, one with metastases and the other two with psammoma bodies and amyloid, respectively, are described. Neoplastic cells of all patients reacted with antihuman insulin antibody using the peroxidase-antiperoxidase (PAP) method. Ultrastructurally, neoplastic cells consisted of light cells and dark cells, both of which had a large number of secretory granules, microfilaments, ceroid bodies, and phagolysosomes. Psammoma bodies seemed to originate from neoplastic cell debris in one tumor. In another case, amyloid fibrils appeared to be produced by tumor cells, and there was a close association of amyloid with secretory granules.

Adenoma, Islet Cell↗
PubMed1985

Effects of renal denervation on renin release induced by intracerebroventricular administration of biological active peptides in conscious rats.

Experiments were performed to determine whether the renal nerve mediates the renin release induced by intracerebroventricular administration of angiotensin II (ANG II), bradykinin (BK), leucine-enkephalin (Leu-ENK) and neurotensin (NT). In sham-operated rats, both ANG II and NT suppressed plasma renin activity (PRA), BK did not affect PRA, and Leu-ENK increased PRA. Renal denervation abolished the increase in PRA by Leu-ENK. Suppression of PRA by ANG II was attenuated in denervated rats. Renal denervation did not influence the renin release by BK or NT. These results suggest that the renal nerve plays an important role in elevating PRA after central stimulation by Leu-ENK. Although suppression of PRA is mainly mediated by mechanisms other than the renal nerve, the renal nerve partially participates in suppression of PRA by ANG II.

Angiotensin II↗
PubMed1985

Efficacy of an acellular pertussis vaccine in Japan.

To assess the efficacy of an acellular pertussis vaccine that has been used in Japan since 1981, 283 patients with pertussis were selected among patients with suspected pertussis seen at hospitals located around the Tokyo Metropolitan area from 1981 to 1983. The survey of secondary cases in household contacts showed that attack rates in children 0 to 6 years of age were 73.1% in unimmunized children, 15.0% in those fully immunized by whole-cell vaccines, and 15.4% in those given acellular vaccines. The efficacy of Japanese acellular pertussis vaccines was 79% and was not different from that of whole cell vaccines.

Diphtheria Toxoid↗
PubMed1985

Changes of plasma renin activity following intracerebroventricular administration of biologically active peptides in two-kidney, one clip hypertensive rats.

We studied the effects of intracerebroventricular (ICV) administration of angiotensin II (ANG II), bradykinin (BK), leucine-enkephalin (Leu-ENK) and neurotensin (NT) on plasma renin activity (PRA), blood pressure and heart rate in acute (less than 4 weeks) and chronic (more than 12 weeks) two-kidney, one clip (2K-1C) hypertensive rats. These four peptides all produced pressor responses. The pressor responses caused by ICV injection of ANG II, BK, Leu-ENK and NT in hypertensive rats did not differ significantly from the response in normal rats. In both acute and chronic 2K-1C hypertensive rats, ANG II and BK significantly suppressed PRA, NT did not affect PRA, and Leu-ENK produced a significant increase in PRA followed by a significant decrease in PRA. As compared to normal rats, suppression of PRA by ANG II and NT was attenuated or abolished but BK and Leu-ENK produced significant reductions in PRA in 2K-1C hypertensive rats. The results indicate that the effects of these four centrally administered peptides on blood pressure, heart rate and PRA in acute and chronic 2K-1C hypertensive rats were not essentially different from those in normal rats.

Angiotensin II↗
PubMed1985

[The effects of aorto-coronary bypass grafting to totally occluded coronary arteries on left ventricular contractility].

The effects of aorto-coronary bypass grafting (ACBG) on totally occluded coronary arteries (TOCA), postocclusion vessels of which were demonstrated angiographically through collaterals and left ventricular contractility were studied in eleven patients consisted of nine with transmural myocardial infarction (TMMI) on ECG in the area perfused by TOCA and without TMMI. Of eleven ACBG consisting of eight left anterior descending coronary arteries (LAD) and three right coronary arteries (RCA), all eight grafts to LAD were patent, whereas two of three to RCA were obstructed on the postoperative angiogram. The following evaluations were undertaken in the cases with patent grafts. In seven cases with TMMI (six LAD, one RCA), left ventricular ejection fraction (EF) increased from 0.56 +/- 0.08 (Mean +/- SD) to 0.65 +/- 0.07 (p less than 0.01). PLVSP/LVESV slightly increased, but not significantly. Mean Vcf increased from 1.07 +/- 0.33 to 1.83 +/- 0.88 circ/sec (p less than 0.02). Left ventricular segmental wall motion also improved from 23.1 +/- 6.8 to 29.5 +/- 7.2% (p less than 0.01), markedly in the anterior and apical segment. In two cases without TMMI, all of EF, PLVSP/LVESV, Mean Vcf and segmental wall motion improved much more than the cases with TMMI. In conclusion, it was suggested that ACBG to TOCA, especially LAD visualized angiographically through collaterals resulted in the excellent graft patency rate and the significant improvement of left ventricular contractility, even in the cases with TMMI.

Adult↗
PubMed1985

[A case of ossifying fibroma of the skull].

A 23-year-old woman was admitted to our hospital because of a soft, painful mass in the right parietal region for a month. Neurological examination revealed no abnormality. Laboratory data including serum Ca, P and alkaline phosphatase were normal. Skull x-ray film showed a partially osteolytic, not well circumscribed lesion in the right frontal, parietal and occipital bone. No remarkable sclerotic area was seen in the lesion. CT scan showed that the lesion was located in the diploë, destroying both inner and outer tables of the bone. Right external carotid angiogram revealed that the lesion is supplied by the branches of superficial temporal artery and middle meningeal artery. 99mTc bone scan showed increased uptake in the lesion. The patient underwent a right parietal craniectomy. The skull bone was invaded by the tumor, which was yellow-brown in color, thickened and fragile. We could easily perforate it through. The tumor didn't invade the dura mater or periosteum. It was extensively removed with an airtome and rongeurs. A cranioplasty was carried out using a plastic resin. The pathological specimen showed that the tumor was mainly composed of mature, regularly-aligned bone and intermingled fibrous tissue. Neither mitosis nor atypical cellular features was seen. These findings were compatible with the diagnosis of ossifying fibroma. The postoperative course was uneventful and the patient was discharged in a good condition. There was no evidence of local recurrence 10 months later. Ossifying fibroma is a rare, benign bone tumor that mainly involves the craniofacial bone. The differential diagnosis of ossifying fibroma versus fibrous dysplasia is difficult. These diseases can be differentiated on combined clinical, radiological and morphological grounds.

Adult↗
PubMed1984

Cytotoxic action of retinoidal butenolides on mouse neuroblastoma and rat glioma cells.

Proliferation and death were measured in cultures of mouse neuroblastoma N18TG -2 and rat glioma C6BU -1 cells when treated with up to 100 micron retinoidal butenolides (RB 1-6). The number of viable cells in each case was measured with various concentrations of the compounds, of which RB-3 (5-hydroxy-4-[2-(2,6,6,-trimethyl-l- cyclohex en-l-yl) ethenyl ]-2(5H)- furanone ) was the most potent in destroying the cells after 2 days' incubation. ED50 of RB-3 was about 5 X 10(-7) M for both types of cell. RB-3 was 80 times more potent than retinoic acid. Ten analogues of RB-3 had a similar inhibitory effect on DNA synthesis in N18TG -2 cells. The degenerative changes caused by RB-3 in C6BU -l cells were irreversible even when the cells were exposed to it for 2 h. Tumor weights of N18TG -2 cells that had been inoculated subcutaneously onto the backs of A/J mice were 30-40% lower than those of untreated controls after 14 days of single daily i.p. injections of RB-3 doses of 100 mg/kg of body weight. The results indicate that RB-3 is cytotoxic in murine tumor cells originating from the nervous system and has an inhibitory effect on neuroblastoma-tumor growth in mice.

Animals↗