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Biomedical subjects

T Kaneko

Publications and source records attributed to T Kaneko.

At least 289 records · Page 16Linked to original sources
PubMed1999

Time dependency of the ratio of umbilical vein/maternal artery concentrations of vecuronium in caesarean section.

BACKGROUND: The ratio of umbilical vein (UV) and maternal artery (MA) concentrations of vecuronium may more accurately determine the placental transfer ratio during caesarean section. This ratio potentially correlates with the time from induction of anaesthesia to delivery (I-D time). The aim of this study was to determine the UV/MA ratio of vecuronium and its relationship with the I-D time. METHODS: Eighteen pregnant women at full term undergoing caesarean section were studied. The parturient was given intravenously 0.01 mg/kg vecuronium as a priming dose, followed 180 s later by 0.11 mg/kg vecuronium as an intubation dose and 4 mg/kg thiamylal. The time from the injection of the intubation dose to the clamping of the umbilical cord was regarded as the I-D time. At the time of clamping the umbilical cord, blood samples were collected and the UV and MA of vecuronium were measured. RESULTS: The UV/MA ratio and the I-D time, expressed as the mean (SD), were 0.056 (0.016) and 280 (57) s, respectively. The regression equation indicated y = 0.0083 + 0.00017 x (R2 = 0.381, r = 0.617, P = 0.0063, I-D time (s) = x, UV/MA = y). CONCLUSION: The present study demonstrated that the UV/MA ratio of vecuronium as an index of the placental transfer becomes smaller as the delivery time after injection of this drug becomes shorter during caesarean section.

Adult↗
PubMed1999

Are there any relationships between the fecundity of bilateral ovaries in an individual patient and the incidence of apoptotic granulosa cells?

Many researchers have discussed fecundity on a per patient or per ovarian follicle basis. In contrast, this study was undertaken on a per ovary basis, and tests the hypothesis that there is a relationship between the fecundity of the bilateral ovaries in an individual patient and the incidence of apoptotic granulosa cells. The two ovaries of 10 women undergoing ovulation induction for in-vitro fertilization (IVF) with gonadotrophin-releasing hormone analogue (GnRHa) and gonadotrophins were compared. There was no difference in apoptotic index in granulosa cells and various hormones in the follicular fluids. Our results indicate that, in the ovulation induction protocol for IVF, GnRHa and gonadotrophins, there is no predisposition of one ovary over the other in an individual patient in terms of apoptosis at the time of aspiration, even though the number of oocytes in each ovary is different, because the number of oocytes retrieved may reveal ovarian fecundity before stimulation with GnRHa + human menopausal gonadotrophin (HMG).

Apoptosis↗
PubMed1999

Human renin-binding protein is the enzyme N-acetyl-D-glucosamine 2-epimerase.

The existence of human renin-binding protein (RnBP) in the kidney has been shown by the isolation and characterization of a complex of porcine renin-human RnBP [S. Takahashi et al. (1985) J. Biochem. 97, 671-677]. However, the properties of the free form of human RnBP had not been understood, because of the limitation of materials. In the present study, we have expressed human RnBP in Escherichia coli JM 109 cells under the transcriptional control of taq promoter and purified it by conventional column chromatographies. The purified recombinant human RnBP (rhRnBP) exists as a dimer and inhibits porcine renin activity through formation of a complex of porcine renin with rhRnBP, the so-called high-molecular-weight renin. Moreover, the rhRnBP catalyzes the interconversion between N-acetyl-D-glucosamine (GlcNAc) and N-acetyl-D-Mannosamine (ManNAc) with the apparent Km values of 21.3 mM for GlcNAc and 12.8 mM for ManNAc, and 0.13 mM for effector ATP. ATP is essential for the GlcNAc 2-epimerase activity of human RnBP. These results indicate that the human RnBP is a GlcNAc 2-epimerase.

Amino Acid Sequence↗
PubMed1999

Identification of cysteine-380 as the essential residue for the human N-acetyl-D-glucosamine 2-epimerase (renin binding protein).

Renin binding protein (RnBP) is a proteinous renin inhibitor firstly isolated from porcine kidney. Recently, the protein was identified as the enzyme, N-acetyl-D-glucosamine (GlcNAc) 2-epimerase. The GlcNAc 2-epimerase activity of recombinant human RnBP was specifically inhibited by SH-reagents such as N-ethylmaleimide, 5, 5'-dithiobis-2-nitrobenzoate, and iodoacetic acid, indicating that the most probable reactive site is a cysteine residue. To identify the active site residue(s), we have constructed ten cysteine residue mutants (C41S, C66S, C104S, C125S, C210S, C239S, C302S, C380S, C386S, and C390S) for human GlcNAc 2-epimerase and expressed them in Escherichia coli cells. The relative specific activities of C41S, C66S, C125S, C210S, C239S, C302S, C386S, and C390S are nearly the same to that of the wild-type enzyme. The specific activity of the C104S mutant is 26% of that of the wild-type enzyme. The expression of the C380S mutant in E. coli cells was detected on Western blotting, whereas GlcNAc 2-epimerase activity was not detected in the extract. These results indicate that Cys380 is essential for the enzymatic activity of human GlcNAc 2-epimerase.

Animals↗
PubMed1999

Studies on the cell-type specific expression of RBP-L, a RBP-J family member, by replacement insertion of beta-galactosidase.

The RBP-L gene encodes a DNA binding protein that is structurally related to RBP-J, the mammalian homolog of Drosophila Suppressor of Hairless. Although the RBP-L protein binds the same DNA sequence as RBP-J, the in vivo function of this protein remains largely unknown. In order to investigate the role of this protein, we generated RBP-L mutant mice by targeted disruption involving replacement of the protein-coding sequence in the first exon with an in-frame fusion of the nlacZ cDNA. The homozygous mutant mice appeared morphologically normal and fertile. Unexpectedly, we found the possible existence of additional promoter(s) downstream of the first exon whose activity was not fully disrupted in the mutant mice. The promoter upstream of the first exon is regulated in a cell type-specific manner so that transcription is active in neurons but almost inactive in lung where the downstream promoter is active. The specific expression of the beta-galactosidase fusion protein was detected in layer VI of the cerebral cortex, in the pyramidal cell layer of the hippocampus, and in the granule cell layer of the dentate gyrus. Furthermore, we found that the upstream promoter activity in neurons might be regulated by some neuronal activity.

Amino Acid Sequence↗
PubMed1999

Percolation in ionic fluids and formation of a fractal structure.

The size of a dense region in the nonuniform distribution of particles generated in an ionic fluid can develop under certain conditions, as the charge on each particle increases. To derive this result, it is assumed that such a dense region is an ensemble of particles linked to each other as particle pairs that satisfy the condition E(ij)+u(ij)(r)< or =0, where E(ij) is the relative kinetic energy for i and j particles and u(ij)(r) the Coulomb potential. The percolation of the ensemble can be estimated analytically. The result described above has been derived from this estimation. According to the pair connectedness function derived for analytic estimation of the percolation, the dense region resulting from the contribution of the Coulomb attractive force between positive and negative particles can produce a fractal structure with a fractal dimension of 1.5. Furthermore, a configuration of charged particles, which can be approximately drawn from a characteristic of the pair connectedness function, agrees with that of the Bjerrum theory.

Journal Article↗
PubMed1999

Mucosa-associated lymphoid tissue (MALT) lymphoma of the rectum with chromosomal translocation of the t(11;18)(q21;q21) and an additional aberration of trisomy 3.

A rare case of primary mucosa-associated lymphoid tissue lymphoma (MALT) of the rectum is reported. A 56-yr-old man was referred to our hospital for further examination and treatment of rectal neoplasm. A physical examination and laboratory data showed no special abnormalities. However, endoscopic colorectal observation revealed multiple red and slightly elevated nodular lesions with erosive changes of the rectum. The lesions were composed of diffuse, small atypical lymphoid cells (i.e., centrocyte-like cells) and were stained with L26 and BCL-2 but not cyclin D1. Surface markers of cells obtained from biopsy specimens were CD5-, CD10-, CD19+, CD20+, kappa+, and lambda-. No BCL-2 gene rearrangement was observed. The clonal karyotype of t(11;18)(q21;q21) was observed in six of nine lymphoid cells. Trisomy was also identified two of 144 cells by fluorescence in situ hybridization. We report a rare case of the rectal MALT lymphoma bearing characteristic chromosomal aberrations; t(11;18)(q21;q21) and trisomy 3. We suggest that chromosomal analysis using biopsy specimens may be useful for the diagnosis of MALT lymphoma.

Chromosomes, Human, Pair 11↗
PubMed1999

Primary intraosseous carcinoma of the mandible with probable origin from reduced enamel epithelium.

This report describes a case of primary intraosseous carcinoma (PIOC) arising de novo in the mandible. The patient was a 74-year-old woman and an early PIOC was found incidentally during histopathological examination of the pericoronal tissue obtained at extraction of a deeply impacted third molar. The curetted soft tissues consisted of a microinvasive, keratinizing squamous cell carcinoma with scattered foci of carcinoma cells showing calcification; stromal osseous metaplasia was also observed. After additional treatment, the patient has remained free of disease for 2 years. Since the tumor was completely enclosed in the bone, the only identifiable source of the present PIOC is the reduced enamel epithelium. Despite its rarity, this case emphasizes the importance of careful histologic examination of all apparently innocuous dental follicles that are removed surgically.

Aged↗
PubMed1999

Induction of anti-thymocyte/T lymphocyte antibodies in mice injected with lipopolysaccharides from periodontopathic bacteria.

We examined the levels of anti-thymocyte/T lymphocyte autoantibody (ATA) in the serum of mice injected intraperitoneally with lipopolysaccharides (LPS) from periodontopathic bacteria; Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Capnocytophaga ochracea, and non-oral Escherichia coli. All of the LPS induced IgM-ATA. Among these, LPS from C. ochracea induced the highest level of IgM-ATA, whereas that of P. gingivalis induced the lowest. The peritoneal T lymphocytes of mice injected with LPS were bound by IgM-ATA. Peritoneal B-1 (CD5+B) cells stimulated by each LPS produced much more IgM-ATA than splenic B-2 (CD5-B) cells, suggesting that B-1 cells might be responsible for the production of these antibodies. Serum of mice injected with C. ochracea and F. nucleatum LPS showed cytotoxicity against thymocytes in the presence of rabbit complements. Binding and cytotoxicity were confirmed by IgM purified from serum of the mice injected with C. ochracea LPS. Furthermore, serum of mice treated with C. ochracea, F. nucleatum or A. actinomycetemcomitans LPS inhibited the proliferation of thymocytes. However, purified IgM from the serum of mice treated with C. ochracea LPS failed to produce the same inhibition. Our results suggest that LPS from certain species of periodontopathic bacteria can induce IgM-ATA in the serum and these antibodies may modulate the local immune network in periodontal tissues.

Aggregatibacter actinomycetemcomitans↗
PubMed1999

Effective intra-arterial chemotherapy for acinar cell carcinoma of the pancreas.

A 41-year-old man with a huge pancreatic tumor (acinar cell carcinoma) was treated by intra-arterial infusion chemotherapy with 5-fluorouracil (5-FU), mitomycin C (MMC) and cisplatin (CDDP). The tumor was significantly reduced, and he underwent a pancreaticoduodenectomy with complete excision of the tumor. Unfortunately multiple metastatic liver tumors were noted 5 months after resection. These tumors could also be markedly reduced by intra-arterial chemotherapy and the survival period was prolonged to 18 months. He suddenly died of sepsis but not from the pancreatic carcinoma. This case shows that intra-arterial infusion chemotherapy with 5-FU, MMC and CDDP can be an effective regimen for the treatment of acinar cell carcinoma of the pancreas.

Adult↗
PubMed1999

Calcification in untreated non-Hodgkin's lymphoma of the jejunum.

A 69-year-old Japanese female was admitted to our hospital due to a 2-month history of vomiting after eating. Examination of the small intestinal tract revealed a tumor with calcification in the inner portion, from the horizontal portion to the ascending portion of the duodenum, and jejunojejunostomy was performed. The pathological findings of the tumor gave a diagnosis of non-Hodgkin's lymphoma, diffuse small cleaved cell (Working Formulation classification), B cell type, of the jejunum. Calcification is rarely found in untreated malignant lymphoma and 15 cases of untreated malignant lymphoma with calcification have been reviewed.

Adolescent↗
PubMed1999

Superoxide mediates cigarette smoke-induced infiltration of neutrophils into the airways through nuclear factor-kappaB activation and IL-8 mRNA expression in guinea pigs in vivo.

We examined the hypothesis that superoxide mediates infiltration of neutrophils to the airways through nuclear factor (NF)-kappaB and interleukin-8 (IL-8) after acute exposure to cigarette smoke (CS) in vivo. Male Hartley strain guinea pigs were exposed to air or 20 puffs of CS and killed 5 h after the exposure. The differential cell count of bronchoalveolar lavage fluid and specific myeloperoxidase enzyme assay demonstrated that acute exposure to CS caused neutrophil accumulation to the airways and parenchyma, respectively. Acute exposure to CS increased DNA-binding activity of NF-kappaB in the lung. Acute exposure to CS also increased IL-8 messenger RNA (mRNA) expression in the lung. Pretreatment of guinea pigs with recombinant human superoxide dismutase (rhSOD) aerosols reduced the CS-induced neutrophil accumulation to the airways. Both activation of NF-kappaB and increased IL-8 mRNA expression were also inhibited by the pretreatment of rhSOD aerosols. Strong immunoreactivities for p65 and p50 were detected in the nuclei of alveolar macrophages after acute exposure to CS. The signal for IL-8 mRNA expression was demonstrated in the alveolar space after acute exposure to CS. Neither significant immunoreactivities for p65 and p50 nor IL-8 mRNA signals were observed in airway epithelium. These observations suggest that acute exposure to CS initiates superoxide-dependent mechanism that, through NF-kappaB activation and IL-8 mRNA expression, produces infiltration of neutrophils to the airways in vivo. It was also suggested that the alveolar macrophage is one potential source of NF-kappaB activation and IL-8 mRNA expression after acute exposure to CS.

Animals↗
PubMed1999

In vivo sequential changes in chloride cell morphology in the yolk-sac membrane of mozambique tilapia (Oreochromis mossambicus) embryos and larvae during seawater adaptation

Changes in chloride cell morphology were examined in the yolk-sac membrane of Mozambique tilapia (Oreochromis mossambicus) embryos and larvae transferred from fresh water to sea water. By labelling chloride cells with DASPEI, a fluorescent probe specific for mitochondria, we observed in vivo sequential changes in individual chloride cells by confocal laser scanning microscopy. In embryos transferred from fresh water to sea water 3 days after fertilization, 75 % of chloride cells survived for 96 h, and cells showed a remarkable increase in size. In contrast, the cell size did not change in embryos and larvae kept in fresh water. The same rate of chloride cell turnover was observed in both fresh water and sea water. Using differential interference contrast (DIC) optics and whole-mount immunocytochemistry with anti-Na(+)/K(+)-ATPase, we classified chloride cells into three developmental stages: a single chloride cell without an apical pit, a single chloride cell with an apical pit, and a multicellular complex of chloride and accessory cells with an apical pit. DIC and immunofluorescence microscopy revealed that single chloride cells enlarged and were frequently indented by newly differentiated accessory cells to form multicellular complexes during seawater adaptation. These results indicate that freshwater-type single chloride cells are transformed into seawater-type multicellular complexes during seawater adaptation, suggesting plasticity in the ion-transporting functions of chloride cells in the yolk-sac membrane of tilapia embryos and larvae.

Journal Article↗
PubMed1999

Digestibility of the hydrogenated derivative of an isomaltooligosaccharide mixture by rats.

The digestibility of the hydrogenated derivative of an isomaltooligosaccharide mixture (IMO-H) was investigated. In an in vitro experiment, the digestibility of IMO-H was examined by models of the digestive system. IMO-H was resistant to two types of alpha-amylase and to artificial gastric juice. Enzymes in the rat small intestinal mucosa hydrolyzed tri-, tetra- and higher saccharide alcohols to disaccharide alcohol, removing successive glucose units from the non-reducing ends of the chains. The hydrolysis ratio for IMO-H was intermediate between the values for maltose and maltitol. In an in vivo study, growing rats were fed on an experimental diet containing IMO-H, maltitol, or hydrogenated palatinose in the range from 5% to 20%. The growth parameters of the rats fed on the test sugar show that the availability of IMO-H was about 1.2 to 1.25 times that of maltitol or hydrogenated palatinose.

Animals↗
PubMed1999

Protective effect of flavonoids on endothelial cells against linoleic acid hydroperoxide-induced toxicity.

The protective effect of flavonoids against linoleic acid hydroperoxide (LOOH)-induced cytotoxicity was examined by using cultured endothelial cells. When the cells were incubated with both LOOH and flavonoids, most flavonols protected the cells from injury by LOOH. Flavones bearing an ortho-dihydroxy structure also showed a protective effect against the cytotoxicity of LOOH. However, flavanones had no effect. The structure-activity relationship revealed the presence of either the ortho-di-hydroxy structure in the B ring of the flavonoids or 3-hydroxyl and 4-oxo groups in the C ring to be important for the protective activities. The interaction between flavonoids and a-tocopherol was also examined in this system. Flavonoids that were protective against LOOH-induced cytotoxicity had at least an additive effect on the action of alpha-tocopherol against LOOH-induced damage.

Antioxidants↗
PubMed1999

Simultaneous evaluation of spatial working memory and motivation by the allocentric place discrimination task in the water maze in rats.

In order to evaluate learning and memory deficits separately from and simultaneously with motivational, motor and sensory impairments in identical animals, we developed the allocentric place discrimination task test using a water maze in rats. For this assessment task, two similar, visible platforms, one was fixed and the other was floating, were simultaneously present in a pool, and the working memory of the allocentric place discrimination task was evaluated. After training, the task accuracy was high about 85% correct and animals were used repeatedly. The accuracy decreased significantly when the pool was surrounded with a black curtain. Muscarinic receptor antagonist scopolamine 0.5 mg/kg selectively impaired the accuracy. Muscle relaxant dantrolene 10 mg/kg selectively decreased swimming speed. Under low motivational condition (warm water), still time increased and swimming speed decreased, but the accuracy was not affected. Similar to warm water, opioid receptor agonist morphine 15 mg/kg increased still time and decreased swimming speed. These results suggest that the allocentric place discrimination task is useful in evaluating spatial working memory ability independently of and concurrently with also visual, motor ability and motivation in identical animals.

Analgesics, Opioid↗