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T Kikuchi

Publications and source records attributed to T Kikuchi.

At least 415 records · Page 23Linked to original sources
PubMed1993

Fine structure of the lamina basilaris of guinea pig cochlea.

The lamina basilaris of guinea pig cochlea was studied with SEM after trypsin treatment, and with TEM of resin sections and deep-etching replicas. The lamina consists of radial, evenly compacted filaments in the zona arcuata, and radial, discretely bundled filaments in the zona pectinata. In both zones, elementary filaments measured about 12 nm in thickness on the replica. The filaments formed more or less irregular passing bridges with each other and, eventually, a three-dimensional network which was continuous with the basement membrane under the supporting cells.

Animals↗
PubMed1993

Multiple pathways lead to activation of the survival mechanism in quiescent BALB/c-3T3 cells.

The survival of density-arrested quiescent murine BALB/c-3T3 cells in serum-free Dulbecco's medium requires the presence of cell growth factors or second messenger agonists. The protein synthesis inhibitor anisomycin blocks the survival-mediating action of the basic fibroblast growth factor (bFGF) and of 12-O-tetradecanoylphorbol 13-acetate (TPA), but has little or no effect on the protective action of platelet-derived growth factor or 8-bromoadenosine 3':5'-cyclic monophosphate (Br-cAMP). The effects of anisomycin are concentration dependent in the range from 2.5 to 25 microM and show that the survival-enhancing abilities of bFGF and TPA critically require protein synthesis, whereas those of platelet-derived growth factor and Br-cAMP do not. The survival-mediating action of bFGF and TPA can also be blocked with the RNA synthesis inhibitors actinomycin D and 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), whereas the action of platelet-derived growth factor and Br-cAMP is largely resistant. Results on the time course of action of DRB, a selective inhibitor of the synthesis of mRNA precursor molecules, suggest that the RNA required for the survival-enhancing action of bFGF and TPA is present in cells at the time of serum withdrawal and addition of the survival factor and has a half-life greater than 3 h. The new evidence provides further support for the hypothesis that protection of serum-deprived, density-arrested BALB/c-3T3 fibroblasts against death can be achieved either via pathways that entail the synthesis of protein and RNA (e.g., via diacylglycerol-protein kinase C) or via pathways that do not involve de novo biosynthesis (e.g., via cAMP-protein kinase A).

3T3 Cells↗
PubMed1993

Pharmacologic profile of endothelinA/B antagonist, [Thr18, gamma methyl Leu19]endothelin-1.

The pharmacologic profile of [Thr18,gamma methyl Leu19]endothelin-1 (TM ET-1) was investigated in several in vitro and in vivo studies. We found that TM ET-1 inhibited 125I-ET-1 binding in porcine cardiac membrane (ETA receptor) and in bovine brain membrane (ETB receptor), with IC50 values of 0.7 and 0.25 nM, respectively. These values were almost comparable to those for ET-1. TM ET-1 had no effect on intracellular Ca2+ concentration ([Ca]i) in A10 cells mediated by ETA receptors, even at 10(-5) M, or in mouse peritoneal macrophages (MPMs) mediated by ETB receptors, even at 10(-6) M. Increases in [CA]i in A10 cells by ET-1 and in MPMs by ET-3 were completely blocked by pretreatment with 10(-7) M of TM ET-1. In porcine right coronary arteries (PCAs) and in great cardiac veins (PCVs), TM ET-1 caused no contraction at concentrations < or = 10(-6) and 10(-7) M, respectively, although it competitively inhibited ET-1-induced contraction of PCAs and Ala1,3,11,15-ET-1-induced constriction of PCVs with pA2 values of 7.0 and 9.2, respectively. Furthermore, TM ET-1 was more potent than BQ123, an ETA-specific antagonist, in inhibiting the rise in perfusion pressure in a hind-limb preparation in vitro and the increase in blood pressure in rats. These results suggest that TM ET-1 is a potent ETA and ETB antagonist without agonistic effects and can be used in future studies to help clarify the physiological role of ET.

Animals↗
PubMed1993

[Evaluation of the cases of benign disease with high accumulation on the examination of 18F-fluorodeoxyglucose PET].

In this study 39 cases of abdominal benign disease were examined by PET using 18F-fluorodeoxyglucose (FDG), and 11 cases of them (i.e. 4 cases of liver abscess, 1 of pelvic abscess, 1 of omental abscess, 2 of chronic pancreatitis, 1 of inflammatory pseudotumor of liver, 1 of retroperitoneal leiomyoma and 1 of solid and cystic tumor of pancreas) which showed as high accumulation of FDG as malignant lesion were investigated of their clinical and pathological feature. We used Ci/Cp ratio as index to express the accumulation of FDG in the lesion, which was calculated from radioactivities of the lesion (Ci) and the plasma (Cp) at 60 mins after injection of FDG. The Ci/Cp ratio of the 11 cases was 3.64 +/- 0.77. The pathological feature of the 9 inflammatory cases was high accumulation of inflammatory cells and that of the 2 benign tumor cases was solid proliferation of tumor cells. The serum of the 9 inflammatory cases showed high CRP value. It was considered that the high accumulation of FDG in inflammatory lesions was due to piles of FDG uptake of the many inflammatory cells, while the 2 benign tumors of high accumulation were considered that the tumor cell had as high glucose metabolism as malignancies.

Chronic Disease↗
PubMed1993

[Effects of MRX-III on chronic renal failure in rats].

The effects of MRX-III, a new amino acid solution for renal failure, on survival, progression of renal insufficiency, metabolism of calcium and phosphorous, and nutritional status were studied in rats with chronic renal failure induced by 7/8 renal ablation. These rats were injected intraperitoneally with MRX-III, an essential amino acid solution for renal failure (Amiyu; Sol. A) or a general amino acid solution (Moripron-F; Sol. M) for 12 weeks under the condition of a 3.5% protein diet, and these effects were compared with those in control rats infused with Sol. M under a 22% protein diet.1) Infusion of MRX-III or the other solutions under a low protein diet prolonged survival time and improved the uremic status indicated by azotemia, polyuria, albuminuria, hypocalcemia and hypertension. 2) Increase in body weight and tissue weight of rats treated with MRX-III or Sol. A was better than those in rats treated with Sol. M. MRX-III as well as Sol. A showed a tendency to provide a better nutritional effect in comparison with Sol. M.

Amino Acids, Essential↗
PubMed1993

Pulmonary vascular disease and operative indications in complete atrioventricular canal defect in early infancy.

Pulmonary vascular disease was morphometrically analyzed in 67 patients (mean age, 19 months) with isolated complete atrioventricular canal defect. Complete obstruction of the small pulmonary arterial lumen resulting from acute fibrous proliferation and atrophy of the peripheral arterial media, which were considered absolute operative contraindications, were characteristic in six patients with Down's syndrome. Morphometric analysis of medial thickness revealed that thinning of the media of the small pulmonary arteries is generally observed at around 6 months of age in patients with complete atrioventricular canal defect and that the media in patients who have complete atrioventricular canal defect and Down's syndrome was thinner than that in such patients without Down's syndrome. These results suggest that thinning of the media as a result of two factors--Down's syndrome and aging--facilitates the rapid occurrence of fibrous intimal proliferation. Therefore intracardiac repair is desirable within 6 months of life, before medial thinning, in patients with complete atrioventricular canal defect and Down's syndrome. Excluding patients with absolute operative contraindications, the scores of the index of pulmonary vascular disease in operative survivors were below 2.0 and death occurred when scores were more than 2.2. The pulmonary vascular resistances measured in room air and by the oxygen inhalation and tolazoline tests in patients with operative contraindications were more than 7.3, 3.8, and 6.6 units.m2, respectively. We thus conclude that lung biopsy should be undertaken for patients in whom pulmonary vascular resistance is beyond these values to determine the appropriateness of surgical intervention.

Child↗
PubMed1993

[Ring eosinophils in patients with lowered eosinophil peroxidase activity].

Leucocyte cytograms were obtained by using a Technicon H6000 (Technicon Instrument Corporation, Tarrytown, NY, USA) in conjunction with an automated flow-cytochemical analyser by which leucocytes can be differentiated by cytochemical (peroxidase activity) and optical (cell size) methods. By analysis of cytograms obtained in this way, we found twelve cases of lowered eosinophil peroxidase activity among approximately 600,000 blood samples-days between 1984 and 1989. Ring eosinophils were observed on the peripheral blood smears in 2 out of 12 cases. The first case was a 41-year-old female confined to hospital with Hashimoto's disease, and the other a 54-year-old female hospitalized for trauma. In both cases, the percentage of eosinophils was normal, although some had ring-shaped nuclei with a large central nuclear hole and a nuclear ring formed with a thin nuclear chromatin bridge. Ring eosinophils previously have been described in patients with hematological malignancy, hypereosinophilic syndrome or severe alcoholism. Recently we observed ring eosinophils in a healthy individual for the first time. Although ring eosinophils may not have specific diagnostic significance, these cases are reported because they displayed a rare phenomenon.

Adolescent↗
PubMed1993

[Lateral medullary syndrome due to cavernous malformation in the brain stem].

A 59-year-old female was admitted with complaints of vertigo, dysarthria and dysphagia. On neurological examination, right-sided cranial nerve signs included ptosis, Bruns's nystagmus, decreased corneal sensation, diminished facial pain and temperature sensation, decreased palatal excursion and loss of gag reflex. There was no evident motor weakness, but deep tendon reflexes were slightly exaggerated on the left extremities. Coordination testing showed right cerebellar signs. Sensory examination of the remaining parts of the body was quite normal. X-ray CT scan showed multiple high density areas in the right medulla, right pons, right temporal and frontal lobes. T2 weighted MRI demonstrated these lesions as mixed signal intensity areas with marked low signal intensity rim. There were multiple black dots in the bilateral frontal and temporal lobes, cerebellar hemispheres on T2-weighted images. Carotid and vertebral angiograms showed no abnormality. This is the first report of the cavernous malformation presenting as lateral medullary syndrome.

Cavernous Sinus↗
PubMed1993

[A case report of Konno's operation for discrete type subaortic stenosis associated with previous VSD closure and repair of coarctation].

A patient, 1 year and 3 month old boy, underwent Konno's operation for severe discrete type subaortic stenosis, which had developed after the coarctation repair (Subclavian Flap Method) at 15 day old and VSD closure at 21 day old. Konno's operation was performed successfully with SJM 21A and postoperative course was uneventful. The discrete type subaortic stenosis may also develop after VSD closure complicating with coarctation complex. Konno's operation is an acceptable method and stenotic left ventricular outflow tract can be enlarged sufficiently in even young infants. This is the youngest patient treated successfully with Konno's operation in Japan.

Aorta, Thoracic↗
PubMed1992

Woodfruticosin (woodfordin C), a new inhibitor of DNA topoisomerase II. Experimental antitumor activity.

Woodfruticosin (woodfordin C) (WFC), a new inhibitor of DNA topoisomerase II (topo-II), was isolated from methanol extract of Woodfordia fruticosa Kurz (Lythraceae) and studied for in vitro and in vivo antitumor activities in comparison with Adriamycin (ADR) and etoposide (ETP), well known inhibitors of topo-II. The inhibitory activity against DNA topo-II shown by WFC was much stronger than that shown by ETP or ADR. WFC inhibited strongly intracellular DNA synthesis but not RNA and protein synthesis. On the other hand, WFC had a weaker growth inhibitory activity against various human tumor cells than ETP or ADR, but it showed remarkable activity against PC-1 cells and moderate activity against MKN45 and KB cells. Furthermore, WFC had in vivo growth inhibitory activity against s.c. inoculated colon38. These results indicate that the mechanism by which WFC exhibits antitumor activity may be through inhibition of topo-II.

Animals↗