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Biomedical subjects

M Watanabe

Publications and source records attributed to M Watanabe.

At least 253 records · Page 14Linked to original sources
PubMed2001

Sclerosing cholangitis and systemic lymphadenopathy.

A 48-year-old man was admitted to our hospital with jaundice and systemic lymphadenopathy. Cholangiographic findings and liver histology disclosed the presence of sclerosing cholangitis. The patient also had a marked polyclonal increase in IgG levels. The cholangiographic findings, the systemic lymphadenopathy, and the increase in IgG levels resolved completely after treatment with prednisolone. This case suggests that there is an association between sclerosing cholangitis and immunologic abnormalities, and that corticosteroid treatment is useful for this disorder.

Cholangitis, Sclerosing↗
PubMed2001

Nonrotation of the midgut with appendiceal mucocele in an adult.

Nonrotation of the midgut in adults and appendiceal mucocele are both rare pathological conditions. We report here the first case of nonrotation of the midgut associated with appendiceal mucocele. The patient was a 51-year-old man admitted to hospital with ileus. An upper gastrointestinal series and a barium enema revealed nonrotation of the midgut without midgut volvulus and with a mass in the ileocecal area. Laparotomy revealed an appendiceal mucocele adhering to the urinary bladder and the rectum. The mucocele had partly ruptured; yellowish mucinous material had entered the abdominal cavity, resulting in pseudomyxoma peritonei. Histological examination revealed a mucinous tumor of the appendix with borderline malignancy. In this patient, the ileus was caused by the appendiceal mucocele rather than being caused by nonrotation of the midgut.

Appendix↗
PubMed2001

Bilirubin calculi crushing by laser irradiation at a molecular oscillating region wavelength based on infrared absorption spectrum analysis using a free-electron laser: an experimental study.

We investigated a new laser technique of crushing bilirubin calculi, our aim being to crush calculi in isolation using a minimally invasive procedure. Infrared absorption spectrum analysis of the bilirubin calculi was conducted, revealing maximum absorption spectrum at a wavelength of the C=O stretching vibration of ester binding that exists within the molecular structure of bilirubin calcium. As an experiment to crush calculi using the free-electron laser, we set the laser at the effective irradiation wavelength of ester binding, and conducted noncontact irradiation of the bilirubin calculi. The calculi began to slowly ablate until the irradiated site had been completely obliterated after 20s of irradiation. Moreover, absorption spectrum analysis of the irradiated site, from a comparison of absorption peak ratios, revealed that absorption peak intensities decreased over time at the absorption wavelength of ester binding. These findings suggest that irradiation of molecular oscillating region wavelengths peculiar to calculi based on infrared absorption spectrum analysis results in the gradual crushing of calculi in isolation by breaking down their molecular structure.

Bilirubin↗
PubMed2001

An obstructed venous aneurysm presenting as an abdominal mass: report of a case.

We report herein the case of a 32-year-old woman found to have a venous aneurysm originating from the ovarian vein. The patient presented with a 9-cm abdominal tumor, and surgery was performed under the preoperative diagnosis of a mesenteric cyst. The tumor was easily ablated from the mesentery and resected with the right ovarian artery and vein. Histologically, the wall of the cyst showed the structure of a vein, and the diagnosis of a venous aneurysm was made. This disease is difficult to diagnose preoperatively when a patient presents with no symptoms other than a palpable mass, or when the lumen is obstructed by thrombus. This report serves to demonstrate that a venous aneurysm should be considered in the differential diagnosis of an asymptomatic abdominal mass.

Adult↗
PubMed2001

Direct evidence for genome segment reassortment between concurrently-circulating human rotavirus strains.

Extensive heterogeneity in electropherotypes observed among group A human rotaviruses has been considered as a result of two major mechanisms; i.e., the accumulation of point mutations and genetic reassortment between concurrently-circulating strains. However, no evidence was reported thus far indicating that any one of field isolates of rotavirus was formed by direct reassortment of concurrently circulating two parental strains. Comparison of the genome of human rotavirus specimens collected over a six year period by electropherotyping and by the sequencing of selected gene segments identified two reassortants that were generated in nature between strains circulating co-dominantly in the same epidemic season. This is the first report directly showing that at least some part of electrophoretic diversity observed among rotavirus strains was explained by genetic reassortment between strains concurrently circulating in the human population. This supports the hypothesis that genetic reassortment among co-circulating strains operates as a key mechanism for the genetic variability of rotaviruses in nature.

Base Sequence↗
PubMed2001

Expression of Fas and Fas ligand in human gastric adenomas and intestinal-type carcinomas: correlation with proliferation and apoptosis.

BACKGROUND: Fas (APO-1/CD95), a member of the tumor necrosis factor/nerve growth factor receptor superfamily, mediates apoptosis in response to agonistic antibodies or Fas ligand (FasL) binding. Previous reports indicated an up-regulation of FasL in gastric carcinomas to evade host immune attack. Fas/FasL expression, however, has not been analyzed in terms of apoptosis and proliferation in gastric adenoma and carcinoma. METHODS: This study was conducted on seven human gastric carcinoma cell lines, 47 gastric adenomas, and 75 intestinal-type adenocarcinomas (48 early and 27 advanced carcinomas). Fas/FasL expression was examined by immunohistochemistry, apoptosis by the terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling (TUNEL) method, and Fas gene mutation by a reverse transcriptase (RT) polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and sequencing method. RESULTS: Fas and FasL expressions were noted in 18 (38.3%) and 17 (36.2%) adenomas, in 21 (43.8%) and 33 (68.8%) early carcinomas, and in 10 (37.0%) and 19 (70.4%) advanced carcinomas, respectively. The frequency of FasL expression was significantly higher in advanced carcinomas than in the early carcinomas and adenomas; in contrast, there was no significant difference in Fas expression among the three groups. The mean apoptotic index (AI) was 4.96+/-0.51 in the adenomas, 2.96+/-0.23 in the early carcinomas, and 1.67+/-0.17 in the advanced carcinomas. A significantly higher Al was noted in the lesions with Fas expression than in those without Fas expression in all three groups. No missense mutations of the Fas gene were detected in any of the gastric carcinoma cell lines, or in the gastric adenomas or carcinomas. CONCLUSIONS: Upregulation of FasL may correlate with the progression of gastric carcinoma. Apoptosis in gastric adenoma and carcinoma cells may occur via Fas-dependent and -independent pathways, but further clarification is needed.

Adenocarcinoma↗
PubMed2001

Biomechanical behaviour of bovine temporomandibular articular discs with age.

The purpose was to evaluate age-associated changes in the creep and restoration properties of bovine temporomandibular joint (TMJ) discs under and after sustained tensile stress. Forty discs were obtained from 7- and 10-year-old cattle, referred to as the adult and mature adult groups, respectively. Tension of 1.0 MPa was applied and sustained for 20 min to specimens from ten right discs and of 1.5 MPa to specimens from ten left discs. After the period of tension for the study of creep, the specimens were removed from the tension devices and their restoration observed for 20 min. For comparative purposes the relevant results for a young adult group were recruited from data on 3-year-old bovine TMJ discs reported in a previous study on viscoelastic properties. In all the specimens the time-dependent creep curves showed a marked change in strain during the initial 5 s, but the elastic moduli at the onset of stress were significantly larger in the mature adult group than in the other groups. After 20-min creep, the strains were decreased in relation to the age of the specimen and were significantly smaller in the mature adult than in the young adult. With regard to regional differences, the medial specimens exhibited significantly smaller strains than the central ones in all three age groups. Furthermore, the residual strains after 20-min restoration also decreased slightly with age. It is concluded that the bovine TMJ disc becomes stiff and acquires the capacity to recover from continuous deformation during growth and maturation. These findings suggest that the TMJ disc can modify its viscoelasticity in order to withstand extrinsic functional stresses.

Aging↗
PubMed2001

Genetic deletions of NCAM and PSA impair circadian function in the mouse.

The adult suprachiasmatic nuclei (SCN) express neural cell adhesion molecule (NCAM) that carries polysialic acid (PSA), a carbohydrate polymer which controls plastic cell-cell interactions in neural tissues. Expression of the three major isoforms of NCAM [180 (principal PSA carrier), 140, and 120 kDa) varies with developmental and physiological state. The requirements for NCAM and PSA in circadian timekeeping function were assessed among three transgenic mutant strains with differing expressions of PSA and NCAM. These included: NCAM(tm3Ciw) mice lacking only NCAM 180; NCAM(tm1Cwr) mice lacking NCAM 180, 140, and PSA; and NCAM(tm1Cgn) mice lacking all NCAM isoforms and PSA. Locomotor activity was stably entrained to a 12-h light/dark cycle (LD) in the NCAM(tm3Ciw) and NCAM(tm1Cwr) mutants, but not in NCAM(tm1Cgn) mutants, where the daily onset and offset of activity were irregular or lost. Under constant darkness (DD), the free-running rhythmicity of the NCAM(tm3Ciw) mutants expressing PSA was similar to wild-type controls, but was markedly disrupted in the majority of the NCAM(tm1Cwr) and NCAM(tm1Cgn) mutants lacking PSA. This analysis indicates that PSA and its NCAM carrier are necessary for stable free-running circadian rhythmicity under DD, and that NCAM, but not PSA, is needed for synchronization to LD. Notably, when NCAM 180 is deleted, NCAM 140 compensates as the PSA carrier, and may assume other SCN-related functions of the NCAM 180 isoform.

Animals↗
PubMed2001

Increase of CD5(+) B cells during adolescence in female mice.

We examined physiological changes in CD5(+) B lymphocytes in mice associated with aging (from 1 or 5 to 50 weeks of age). The most predominant populations of lymphocytes among these mice were mainly CD5(-) B cells in the spleen and peritoneal cavity, and T cells in the thymus. However, in the spleen, CD5(+) B cells increased from 1 to 15 weeks, and then decreased with aging. In the thymus, CD5(+) B cells increased from 3 to 9 weeks of age, and subsequently became more predominant than CD5(-) B cells. In the peritoneal cavity, CD5(+) B cells increased from 5 to 9 weeks of age, became the most predominant population in lymphocytes at 7 to 9 weeks of age, and decreased with aging. The proportion of CD5(+) B cells in total B cells increased from 5 to 7 or 9 weeks of age, and then decreased with aging, with the highest proportion at 9 weeks of age in the spleen (15%), thymus (94%), and peritoneal cavity (54%). These findings indicate that CD5(+) B cells increase physiologically during mouse adolescence, and subsequently decrease with aging.

Aging↗
PubMed2001

Calcium phosphate invert glass-ceramic coatings joined by self-development of compositionally gradient layers on a titanium alloy.

A glass-ceramic layer containing beta-Ca3(PO4)2 crystals could be joined easily with a new type of titanium alloy (Ti-29Nb-13Ta-4.6Zr) consisting of a beta-titanium phase by heating the metal, on which glass powders with a composition of 60CaO x 30P2O5 7Na2O x 3TiO2 were placed, at 800 degrees C in air. Measurement of tensile bonding strength revealed that the joining between the coating layer and the substrate is very strong. Even after the large deformation (e.g., approximately 90 degrees in bending angle) of the titanium alloy, the coating layer was not peeled off from the substrate. A compositionally gradient layer in the TiO2-P2O5-Na2O-CaO system is developed automatically on the titanium alloy during the heating, resulting in the formation of the strong joining. By soaking in simulated body fluid at 37 degrees C, hydroxyapatite phase was formed newly on the surface of the coating layer.

Alloys↗
PubMed2001

Postprandial middle cerebral arterial vasoconstriction in cirrhotic patients. A placebo, controlled evaluation.

BACKGROUND/AIMS: The objective of this study was to determine whether cerebral arterial vasoconstriction occurs in relation to postprandial splanchnic blood pooling in cirrhotic patients. METHODS: The pulsatility and the resistive indexes and blood flow in the middle cerebral artery were measured by magnetic resonance imaging in 21 cirrhotics and 14 controls. These measurements were repeated 30 min after ingestion of a 400 kcal liquid meal or placebo. Seven controls and 14 patients received the meal, and seven controls and seven patients received placebo. RESULTS: In the fasting conditions, cirrhotics had a greater pulsatility index (0.81 +/- 0.10 vs. 0.67 +/- 0.05, P < 0.001) and a greater resistive index (0.61 +/- 0.04 vs. 0.53 +/- 0.04, P < 0.001) and a lower blood flow (127 +/- 42 ml/min vs. 167 +/- 37 ml/min, P < 0.03) in the middle cerebral artery compared with controls. Meal ingestion significantly increased the pulsatility index (P < 0.03) and the resistive index (P < 0.01) and decreased blood flow (P < 0.03) in the middle cerebral artery in cirrhotics but not in controls. In contrast, placebo ingestion had no effect on the hemodynamic parameters in the middle cerebral artery in the two groups. CONCLUSIONS: Results support the hypothesis that middle cerebral arterial vasoconstriction seen in cirrhotic patients is one of the cerebral artery's homeostatic responses to underfilling of the splanchnic arterial circulation.

Adult↗
PubMed2001

Daily variation of azygos and portal blood flow and the effect of propranolol administration once an evening in cirrhotics.

BACKGROUND/AIMS: Esophageal variceal bleeding occur more often at night, however, the mechanism for this remains unclear. This study investigated the daily variation of azygos blood flow (AzBF) and portal blood flow (PBF) and the effects of propranolol administration given once in evening in cirrhotics. METHODS: Blood flow were measured using magnetic resonance imaging. Hemodynamic parameters were determined at 08:00, 16:00 24:00 and again 08:00 h, and were measured at baseline and after 14 days oral administration of propranolol (30 mg, n = 7) or placebo (n = 7) at 19:00 h in 14 patients. RESULTS: A daily fluctuation of AzBF and PBF was observed, peaking at 24:00 h in nine patients. In three other patients, peak AzBF and PBF were observed both at 16:00 and 24:00 h. Two patients were constant throughout the day. When the daily variation was compared, ANOVA showed a significant difference (P < 0.001). Propranolol administration at 19:00 h reduced AzBF (-40.7 +/- 17.9% vs. baseline, P < 0.001) and PBF (-26.5 +/- 10.7% vs. baseline, P < 0.01) at 24:00 h. CONCLUSIONS: We found that in most cirrhotics, AzBF and PBF peaks at midnight. Dosing of propranolol in the evening may be important for its role in preventing variceal bleeding.

Adrenergic beta-Antagonists↗
PubMed2001

Accumulation status of persistent organochlorines in albatrosses from the North Pacific and the Southern Ocean.

Current status of contamination by persistent organochlorines (OCs) such as polychlorinated biphenyles (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), isomers of hexachlorocyclohexane (HCHs), hexachlorobenzene (HCB) and chlordane compounds (CHLs) were examined in 61 individuals belonging to eight albatross species collected from the North Pacific and the Southern Ocean. Generally high OC concentrations were found in albatrosses from the North Pacific than those from the Southern Oceans. Black-footed albatrosses had noticeably high PCBs and DDTs concentrations with mean values of 92 and 33 micrograms/g wet weight in subcutaneous fat, respectively. Among the other OCs, concentration of CHLs was higher than that of HCB in North Pacific albatrosses. HCHs accumulation was the lowest among all the OCs analyzed. Species-specific differences were observed for HCB, CHLs and DDTs in some species in the Southern Ocean. No significant difference of gender and age-related accumulation was observed in total OCs. However, PCB concentrations were higher in mature birds than those from immature ones in the Southern Ocean. Species-specific accumulation patterns of OCs in albatrosses were closely related with their feeding, migration, age and geographical ranges.

Age Factors↗
PubMed2001

X-ray spectral simulation and experimental detection of phosphorus segregation to grain boundaries in the presence of molybdenum.

A fundamental limitation of X-ray energy-dispersive (EDS) spectrometry is the detection and quantitative analysis of characteristic X-rays from one element, in the presence of an overlapping peak from another element. This problem is particularly acute when the unambiguous detection of one element is crucial to ensuring the mechanical performance of the material, such as the presence of an embrittling species. This paper addresses the specific problem of defining the conditions of specimen composition and thickness under which phosphorus can be detected in the presence of molybdenum, since the Mo L1 and the P Kalpha elemental peaks are separated by 2eV. This separation is significantly below the resolution limit of X-ray spectrometry in the electron microscope. Simulations of the X-ray spectra from low-alloy steels have been performed via Desk-Top Spectrum Analyzer and compared with experimental measurements on a field-emission gun VG HB 603 dedicated scanning transmission electron microscope.

Electron Probe Microanalysis↗
PubMed2001

Solving the binding problem of the brain with bi-directional functional connectivity.

We propose a neural network model which gives one solution to the binding problem on the basis of 'functional connectivity' and bidirectional connections. Here, 'functional connectivity' is dynamic neuronal connectivity peculiar to temporal spike coding neural networks with coincidence detector neurons. The model consists of a single primary map and two higher modules which extract two different features shown on the primary map. There exist three layers in each higher module and the layers are connected bi-directionally. An object in the outer world is represented by a 'global dynamical cell assembly' which is organized across the primary map and the two higher modules. Detailed, but spatially localized, information is coded in the primary map, whereas coarse, but spatially extracted information or globally integrated information is coded in the higher modules. Computer simulations of the proposed model show that multiple cell assemblies sharing the same neurons partially can co-exist. Furthermore, we introduce a three-dimensional J-PSTH (Joint-Peri Stimulus Time Histogram) which is capable of tracking such cell assemblies, altering its constituent neurons as in our proposed model.

Action Potentials↗
PubMed2001

Enantioselective synthesis and absolute configuration of (-)-1-(benzofuran-2-yl)-2-propylaminopentane, ((-)-BPAP), a highly potent and selective catecholaminergic activity enhancer.

Enantioselective synthesis and absolute configuration of (-)-1-(benzofuran-2-yl)-2-propylaminopentane ((-)-BPAP), which is a highly potent and selective catecholaminergic activity enhancer (CAE) substance, are described. The synthetic approach consists of the coupling reaction of benzofuran with (R)-N-tosyl-2-propylazirizine or (R)-N-methoxy-N-methylnorvaliamide, followed by appropriate modifications of the resulting coupling products. As the results, (-)-BPAP turned out to have the R configuration, which was finally confirmed by X-ray crystallographic analysis.

Azirines↗