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Biomedical subjects

Y Nishida

Publications and source records attributed to Y Nishida.

538 records · Page 30Linked to original sources
PubMedDate not supplied

Alternative origin for "gain-of-function" by mutant SOD enzyme and for conformational change of normal prion protein.

Capillary electrophoresis and ESI-Mass spectrometry methods have revealed that a hydroperoxo-copper(II) complex with (tpa) (=tris(2-pyridylmethyl)amine) reacts with carbonic anhydrase or amyloid beta-peptide (1-40) as a nucleophile to induce the conformational change of the protein structure, while the Cu(bdpg)-complex ((bdpg)=N,N-bis(2-pyridylmethy)-beta-alanineamide) acts as an electrophile toward the proteins to degrade them under the same experimental conditions. This will lead to suggest that enhanced nucleophilic attack by a copper(II)-peroxide adduct to peptide bonding may be one of the serious origins for the "gain-of-function" by mutant superoxide dismutase and for conformational change of normal prion protein.

Electrophoresis, Capillary↗
PubMedDate not supplied

Negligible ability of oxygen and peroxide ion activation by Al(III) ion is essential for Al(III)-induced neurodegeneration.

The electron densities of the atoms in Fe(II)- or Al(III)-tyrosine hydroxylase (THO) containing oxygen and pterin were calculated by the DFT (Density-functional theory) method. The results obtained are consistent with our previous proposal that oxygen activation in THO proceeds through the formation of an intermediate derived from Fe(II), oxygen, and pterin. Electron donation from substrate to the oxygen molecule is important to cleave the O-O bond, and to give the hydroxylated product. Based on these results, it was concluded that hydroxylation of the aromatic ring does not proceed in the Al(III)-containing THO, and a relationship exists between Al(III) ion and neurodegeneration.

Aluminum↗
PubMedDate not supplied

HTLV-I-associated myelopathy (HAM) in Tokushima Prefecture--geographical and clinical studies in an area between endemic and non-endemic areas of HTLV-I infection.

The geographic distribution and clinical features of patients with HTLV-I-associated myelopathy (HAM) in Tokushima prefecture were investigated. Nine patients were found prior to December 1990. The minimal prevalence was estimated as 1.1 per 100,000 in the general population, and 1 per 1,309 in HTLV-I-seropositive persons. Seven patients were found in the southern district facing the Pacific Ocean, but only 1 patient each was found in the northern and western districts. The age at disease onset ranged from 15 to 53 yr (average 33 yr). The ratio of male to female patients was 1:8. Adult T cell leukemia was associated with HAM in 1 patient, and Hashimoto's disease in 2 patients. These cases have not been reported previously. The route of transmission of HTLV-I was concluded to be vertical in 4 patients and horizontal in 4 patients, but was uncertain in 1 patient. No evidence of transmission by blood transfusion was found in these patients.

Adult↗
PubMedDate not supplied

Angiotensin II-dependent hypertension and the arterial baroreflex.

Angiotensin II (ANG II)-dependent hypertension involves the resetting of the heart rate (HR) and sympathetic baroreflex toward higher pressures in conscious rabbits. The resetting of the HR baroreflex function occurs within minutes of the administration of ANG II, while the resetting of the sympathetic baroreflex requires several days. In conscious rabbits, an intact area postrema (AP) is required for the resetting of either the HR or sympathetic baroreflex function. Data is also presented showing that pretreatment with an alpha-1 adrenergic receptor antagonist prevents the early resetting of the HR baroreflex.

Angiotensin II↗
PubMedDate not supplied

A case of pancreatic serous cystadenoma obstructing the distal pancreatic duct.

We present a case of resected serous cystadenoma of the pancreas inducing marked dilatation of the main distal pancreatic duct. A 68-year-old woman, previously diagnosed with chronic pancreatitis, presented with upper abdominal pain. Abdominal US revealed a highly echoic mass in the pancreas. A CT scan disclosed a low density mass in the pancreas and dilatation of the main peripheral pancreatic duct. The mass demonstrated homogeneous and high signal intensity on T2-weighted magnetic resonance imaging (MRI). Selective abdominal arteriography showed the mass strained by the celiac artery. The tumor markers were CEA (2.4 ng/ml) and CA19-9 (6.1 U/ml). After the diagnosis of serous cystadenoma of the pancreas, the patient underwent distal pancreatectomy and splenectomy. The tumor (2.5 cm in diameter) consisted of grayish-white nodules and occupied the body of the pancreas. The tail of the pancreas was atrophic. Histopathological examination of the specimen showed a multilocular lesion containing numerous cysts with the inner surfaces evenly lined by one layer of cuboid or flat epithelial cells which stained positive for periodic acid-Schiff (PAS), evidencing serous cystadenoma. The patient is doing quite well one and a half years after the operation.

Aged↗
PubMedDate not supplied

Structural variety of copper(II)-peroxide adducts and its relevance to DNA cleavage.

The reactivity of copper (II) compounds with several tetradentate ligands towards some spin-trapping reagents was studied in the presence of hydrogen peroxide. The compounds used in this study are roughly divided into two groups based on the reactivity towards 2,2,6,6-tetramethyl-4-piperidinol (and also 2,2,6,6-tetramethyl-4-piperidone), which are trapping agents for singlet oxygen. 1O2(1deltag); The A-group compounds exhibited a high activity to form the corresponding nitrone radical, which was detected by ESR spectroscopy, but corresponding activity of the B-group compounds was very low. The A-group compounds defined as above exhibited high activity for cleavage of DNA (supercoiled) Form I) in the presence of hydrogen peroxide, yielding DNA Form II (relaxed circular) or Form III (linear duplex) under our experimental conditions ([Cu (II)] = 0.1 approximately 0.5 mM). On the other hand, the B-group compounds effected complete degradation of the DNA (double-strand scission) under the same experimental conditions, formation of Form II or Form III DNA was negligible. Two different DNA cleavage patterns observed for A- and B-group compounds were elucidated by the different structural property of the copper (II)-peroxide adducts, which is controlled by the interaction through both DNA and the peripheral group of the ligand system.

Copper↗
PubMedDate not supplied

Spindle cell carcinoma of the pancreas: a case report.

We report on a resected case of spindle cell carcinoma of the pancreas in a 73 year-old Japanese male who has a history of diabetes mellitus. The patient visited his neighborhood hospital complaining of abdominal pain and was referred to our hospital for further examination of a pancreatic tumor discovered by abdominal ultrasonography. Upon the diagnosis of ductal carcinoma, a distal pancreatectomy with splenectomy was performed. Microscopically, the tumor was composed of spindle cells arranged in interlacing bundles with frequent mitotic figures. The diagnosis of spindle cell carcinoma of the pancreas was confirmed by immunohistochemical studies. To our knowledge, our case is the first resected case of spindle cell carcinoma arising from the pancreas in the English literature.

Aged↗
PubMedDate not supplied

Expression of nitrotyrosine is associated with angiogenesis in esophageal squamous cell carcinoma.

BACKGROUND: In our previous study, it was suggested that nitrotyrosine, a product of nitrogen species, found in esophageal squamous cell carcinoma (ESCC), may contribute to the progression of esophageal cancer. MATERIALS AND METHODS: To clarify whether nitrotyrosine expression is associated with apoptosis and/or angiogenic factors in ESCC, we have analyzed the relationship between nitrotyrosine presence and the apoptosis-related proteins, Bcl-2 and Bax, or CD34, the marker of vascular endothelial cells, by an immunohistochemical approach. RESULTS: Nitrotyrosine was detected in 21 out of 55 esophageal cancers. The correlation between nitrotyrosine presence and Bcl-2, Bax expression or apoptotic index (AI) was not significant. In contrast, nitrotyrosine presence was significantly correlated with the microvessel density (MVD); nitrotyrosine-positive specimens tended to show a high MAD, while nitrotyrosine-negative specimens tended to be associated with a low MVD (p<0.05). CONCLUSION: Our data suggest that NO induces progression of esophageal carcinoma through its effect on angiogenesis, rather than its effect on tumor apoptosis.

Adult↗
PubMedDate not supplied

Accumulation of mast cells and macrophages in focal active gastritis of patients with Crohn's disease.

BACKGROUND/AIMS: Recent studies have shown that focal active gastritis seems to be the typical gastric pathology in Crohn's disease. The aim of this study was to compare the incidence of focal active gastritis, Helicobacter pylori infection and distribution of gastric mast cells and macrophages in patients with Crohn's disease, ulcerative colitis and H. pylori gastritis without inflammatory bowel disease. METHODOLOGY: Patients with histologically confirmed Crohn's disease (n = 25) or ulcerative colitis (n = 25) and control patients without inflammatory bowel disease (n = 25) were included in this study. Biopsy specimens were obtained from the antrum and corpus of each patient, and stained with hematoxylin and eosin and immunostained using antibodies to tryptase (AA1) and CD68. The number of mast cells and macrophages located in the lamina propria was determined. RESULTS: Focal active gastritis was detected in 54% of H. pylori-negative patients with Crohn's disease, but it was not found in patients with ulcerative colitis nor in the control group. The density of mast cells and macrophages in the lamina propria of H. pylori-positive patients was significantly higher than in H. pylori-negative patients in all groups. In the Crohn's disease group, the number of mast cells (antrum; 83 +/- 11, body; 89 +/- 11/mm2) and macrophages (antrum; 94 +/- 22, body; 92 +/- 17/mm2) in the lamina propria of H. pylori-negative patients with focal active gastritis was halfway between that in H. pylori-positive and H. pylori-negative patients. In focal active gastritis, mast cells accumulated at the border of focal active gastritis, whereas macrophages accumulated in the center of such lesions. CONCLUSIONS: Our findings indicated that the diagnosis of focal active gastritis, using immunostain for mast cells and macrophages, is the histological hallmark of gastric Crohn's disease. Macrophages might be associated with the formation of focal active gastritis in patients with Crohn's disease.

Adult↗
PubMedDate not supplied

Renal impairment in urate excretion in patients with Down's syndrome.

Uric acid and creatinine clearance studies were performed in nine subjects with Down's syndrome and in eight mentally retarded controls. The urate clearance was significantly decreased in subjects with Down's syndrome compared with controls. Their mean creatinine clearances were also significantly lower than the controls. No significant differences were shown in erythrocyte lactate dehydrogenase activity, in blood lactate and in blood beta-hydroxybutyrate levels between 20 subjects with Down's syndrome and 16 controls. Glomerular dysfunction would seem to contribute to hyperuricemia in Down's syndrome.

Adolescent↗
PubMedDate not supplied

A clonal human chondrosarcoma cell line produces an anti-angiogenic antitumor factor.

Previously we reported that rabbit costal chondrocytes in primary culture produced an anti-angiogenic anti-tumor factor. We also established a clonal human chondrosarcoma cell line, HCS-2/8, which had typical cartilage phenotypes. In the present study, we investigated whether HCS-2/8 cells produce an anti-angiogenic anti-tumor factor. Serum-free medium conditioned by exposure to HCS-2/8 cells in culture inhibited the proliferation of bovine pulmonary artery endothelial cells in culture. The inhibition was not due to general cytotoxicity because the endothelial cells started to proliferate after the conditioned medium was removed from the cultures. The factor in conditioned medium also inhibited DNA synthesis in bovine pulmonary artery endothelial cells, but not in B16 melanoma cells, normal rat kidney cells or chick embryo fibroblasts. Production of the factor by HCS-2/8 cells did not change during serial passages. It also inhibited angiogenesis in the chorioallantoic membrane of chick embryos induced by B16 melanoma and growth of the tumor transplanted onto the membrane. Treatment with protease destroyed the inhibitory activities of conditioned medium on angiogenesis and tumor growth. These findings suggest that HCS-2/8 cells produce a peptide factor with anti-angiogenic, antitumor activity and that the cell line should be a useful source of the factor.

Animals↗
PubMedDate not supplied

A new anticoagulant medication in cardiac valve replacement.

1. In the mitral valve replacement with Starr-Edwards prosthetic ball valve, the major thromboembolism occurred in 20% of the patients with the silastic ball valve series compared with 6% in those with a metal ball valve series. 2. The anticoagulant effect of Warfarin became stable and the occurrence of thromboembolism was reduced by the addition of Bucolome.

Barbiturates↗
PubMedDate not supplied

A gouty family with increased phosphoribosylpyrophosphate synthetase activity: case reports, familial studies, and kinetic studies of the abnormal enzyme.

Two male patients with urate overexcretion and clinical gout in a family showed activity of phosphoribosylpyrophosphate (PRPP) synthetase in erythrocyte lysates (3.1-fold) greater than that found in normal subjects. Hemolysates from 5 female persons in this family contained (2.7-fold) increased enzyme activity suggesting X-linked dominant transmission of the abnormality. Increased maximal velocity of the enzyme, aberrant protein pattern in polyacrylamide electrophoresis, and increased thermolability in purified enzyme suggested that this enzyme is a mutant one. From these findings, it was assumed that the characteristics of this enzyme were different from 4 previously reported enzymes.

Adenosine Diphosphate↗
PubMedDate not supplied

[Indications for percutaneous transvenous mitral commissurotomy: evaluation according to the Sellors classification].

Fifty-eight consecutive patients underwent percutaneous transvenous mitral commissurotomy (PTMC) for mitral stenosis from August 1987 to June 1990. Patients were divided by echocardiographic characteristics of the mitral valve according to the Sellors classification into three groups: group 1 (mobile cusps, 20 patients), group 2 (thickened cusps, 34 patients), group 3 (rigid cusps, 4 patients). Immediately after PTMC, the mitral valve area increased significantly from 1.41 +/- 0.37 to 2.07 +/- 0.38 cm2 (p < 0.01) in group 1 and from 1.09 +/- 0.21 to 1.64 +/- 0.25 cm2 (p < 0.01) in group 2. The mitral valve area did not increase significantly in group 3 (from 0.82 +/- 0.27 to 1.10 +/- 0.22 cm2). Mitral regurgitation developed or increased in severity in four patients (100%) in group 3 (p < 0.01 vs group 1, 20% and group 2, 21%). The symptomatic improvement was 0% for group 3 (p < 0.01 vs group 1, 90% and group 2, 91%). At follow-up period (mean 24.6 months), symptomatic improvement was maintained in 44 patients (76%) of the total patient population. The mitral valve area was maintained well in group 1 and group 2, but three patients in group 2 showed recurrence of symptoms due to valvular restenosis. PTMC is an effective nonsurgical treatment for patients with mobile or with thickened cusps. Surgical method is preferable for patients with rigid cusps.

Adult↗