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Biomedical subjects

I Baba

Publications and source records attributed to I Baba.

At least 19 recordsLinked to original sources
PubMed2001

A novel C1-using denitrifier alcaligenes sp. STC1 and its genes for copper-containing nitrite reductase and azurin.

A novel denitrifier Alcaligenes sp. STC1 was identified. The strain efficiently denitrifies under an atmosphere of 10% oxygen (O2) where Paracoccus denitrificans, one of the most studied aerobic denitrifiers, had less denitrifying activity, indicating that the strain has an O2-torelant denitrifying system. It denitrified by using C1-carbon sources such as formate and methanol as well as glucose, glycerol, and succinate. The genes for the copper-containing nitrite reductase and azurin of this C1-using denitrifier were cloned. Their predicted products of them were similar to those of their counterparts and the maximum similarities were 90% and 92%, respectively.

Alcaligenes↗
PubMed2000

Involvement of deregulated epiregulin expression in tumorigenesis in vivo through activated Ki-Ras signaling pathway in human colon cancer cells.

To identify the genes located downstream of the activated Ki-Ras signaling pathways in human colon cancer cells, a PCR-based cDNA subtraction library was constructed between HCT116 cells and HCT116-derived activated Ki-ras-disrupted cells (HKe3). One of the genes in HCT116 that was evidently up-regulated was epiregulin, a member of the epidermal growth factor family that is expressed in many kinds of human cancer cells. HKe3-stable transfectants expressing activated Ki-Ras regained over-expression of epiregulin. To further elucidate the biochemical structure and significance of epiregulin expression in tumorigenesis, HKe3-stable transfectants expressing epiregulin (e3-pSE cells) were established. Epiregulin existed as highly glycosylated membrane-bound forms, and TPA rapidly induced ectodomain shedding of epiregulin. Furthermore, the conditioned medium of e3-pSE cells showed more DNA synthesis for 32D cells expressing epidermal growth factor receptor (DER) cells than that of HKe3. Although anchorage-independent growth in soft agar was not observed for e3-pSE cells, tumorigenicity in nude mice was observed evidently, and their growth rate was correlated with each amount of exogenous epiregulin expression. These results suggested that activated Ki-Ras will be one of the factors contributing to the overexpression of epiregulin in human colon cancer cells, and that epiregulin will play a critical role in human tumorigenesis in vivo.

Animals↗
PubMed2000

Bis[N,N-bis(2-hydroxyethyl)dithiocarbamato]dimethyltin(IV).

The title compound, [Sn(CH(3))(2)(C(5)H(10)NO(2)S(2))(2)], has crystallographic mirror symmetry (C-Sn-C on mirror plane) and the coordination polyhedron around the Sn atom is a tetrahedron [C-Sn-C 139.3 (2) degrees and S-Sn-S 82.3 (1) degrees ] distorted towards a skew-trapezoidal bipyramid owing to an intramolecular Sn.S contact [3.0427 (6) A]. The molecules are linked into a linear chain by intermolecular O-H.O hydrogen bonds [O.O 2.646 (3) A].

Journal Article↗
PubMed1998

Induction of cytokine-induced neutrophil chemoattractant in response to various stresses in rat C6 glioma cells.

The effect of stress on the production of cytokine-induced neutrophil chemoattractant (CINC) was examined in rat C6 glioma cells. We studied the production of CINC, an interleukin-8 (IL-8) family protein, with bacterial endotoxin, H2O2, and tumor necrosis factor-alpha (TNF-alpha). Each stress induced CINC mRNA in a concentration-dependent manner. Since stress activates the protein kinases regulating nuclear transcription factors, we examined the effects of protein kinase inhibitors and the over-expression of dominant-negative Ras on CINC mRNA expression. Neither over-expression of dominant-negative Ras nor pretreatment with PD98059 (MEK-1 inhibitor), SB203580 (p38MAPK inhibitor), or GF109203X (protein kinase C (PKC) inhibitor) altered stress-induced CINC mRNA expression. This suggests that the Ras-MAPK, p38MAPK, and PKC pathways are not involved in CINC mRNA expression in glial cells. On the other hand, pretreatment with herbimycin A, a potent tyrosine kinase inhibitor, or Ro31-8220, a non-selective serine/threonine kinase inhibitor, suppressed stress-induced CINC mRNA expression. This indicates that stress-induced CINC mRNA expression is mediated by herbimycin A-, or Ro31-8220-sensitive kinases in glial cells. Since stress activates NF-kappaB and NF-IL6, we examined that the effect of herbimycin A, which suppresses CINC mRNA expression, on NF-kappaB and NF-IL6 activation. Herbimycin A suppressed NF-kappaB but not NF-IL6. These results suggest that in rat glial cells, the factors that induce CINC mRNA expression are mediated by herbimycin A-sensitive NF-kappaB activation, but not through the PKC, Ras-MAPK or p38 MAPK pathways.

Animals↗
PubMed1998

Denitrification by actinomycetes and purification of dissimilatory nitrite reductase and azurin from Streptomyces thioluteus.

Many actinomycete strains are able to convert nitrate or nitrite to nitrous oxide (N2O). As a representative of actinomycete denitrification systems, the system of Streptomyces thioluteus was investigated in detail. S. thioluteus attained distinct cell growth upon anaerobic incubation with nitrate or nitrite with concomitant and stoichiometric conversion of nitrate or nitrite to N2O, suggesting that the denitrification acts as anaerobic respiration. Furthermore, a copper-containing, dissimilatory nitrite reductase (CuNir) and its physiological electron donor, azurin, were isolated. This is the first report to show that denitrification generally occurs among actinomycetes.

Ascomycota↗
PubMed1991

Characterization of platelet aggregation induced by the human melanoma cell line HMV-I: roles of heparin, plasma adhesive proteins, and tumor cell membrane proteins.

We investigated the in vitro mechanism of platelet aggregation induced by HMV-I human melanoma cells. HMV-I cells, in the absence of exogenous plasma proteins, induced platelet aggregation, followed by the release reaction. Heparin at an anticoagulant concentration had no effect on the aggregation. Calcium ion was essential for this tumor cell-platelet interaction and could not be replaced by magnesium. Among the adhesive proteins containing RGD sequences that have been reported to enhance experimental metastasis, fibrinogen and thrombospondin significantly enhanced the aggregation induced by HMV-I cells, fibronectin and von Willebrand factor inhibited it, and vitronectin had no effect. To identify the platelet-aggregating factor(s) of the tumor cells, we have developed a monoclonal antibody against HMV-I cells that can inhibit HMV-I cell-induced platelet aggregation. Immunoprecipitation analysis revealed that this antibody recognized an Mr 71,000 membrane protein. These results suggest that the association between the tumor cells and platelets is mediated by the Mr 71,000 membrane protein recognized by this monoclonal antibody.

Antibodies, Monoclonal↗
PubMed1990

[A well differentiated fibrosarcoma arising in left neck region].

The frequency of a fibrosarcoma, based on current criteria, is less than 10% of soft tissue sarcomas. It is most common in the region of extremities and the trunk and relatively rare in the head and neck region. Therefore, of interest is a case of a well differentiated fibrosarcoma arising in left neck region of a 69-year-old woman that is reported. The excised tumor consisted of a firm, partially lobulated mass with a fibrous capsule that measured 8 cm at its greatest diameter. Histologically, the tumor tissue was rather uniform and often had a fasciculated growth pattern consisting of spindle shaped cells and interwoven collagenous fiber in a parallel fashion. To achieve a diagnosis, it was necessary to differentiate this type of fibrosarcoma from aggressive fibromatosis and myogenic tumor (leiomyoma or leiomyosarcoma).

Aged↗
PubMed1980

H-reflex of the upper extremities in cervical myelopathy.

A study was made of the H-reflex in the upper extremities to express objectively the degree of spastic paralysis in cases of cervical myelopathy. This reflex cannot normally be elicited in healthy persons. The H-reflex was elicited in 63 out of 80 patients with advanced symptoms of cervical myelopathy and was most frequently recorded from the median nerve. The H/M amplitude ratio is used to express the degree of spastic paralysis, the higher the ratio the more severe the dysfunction. The longer the clinical history the greater the tendency for the H-type of reflex to change to the HF-type and the higher the H/M amplitude ratio. The decrease rate of the pre- and post-operative H-reflex was high amongst soft disc cases whilst that in spondylosis and ossification of the posterior longitudinal ligament was low compared to the improvement in symptoms. It is concluded that the H-reflex in the upper extremities is a good method of expressing the degree of spastic paralysis in cervical myelopathy.

Aged↗
PubMed1975

[Studies on the relationship between dental plaque and the hard tissues of healthy and diseased teeth].

1. Dental plaques were detected in all the teeth under investigation, with the exception of impacted teeth. 2. The appearance of the plaques is regular. They occur chiefly in certain zones of the tooth crown and in retention areas. The film thickness ranges from 10 to 60 mum. 3. No alterations of the structure or of the primary texture of the hard tissues were observed on healthy and periodontally diseased teeth. The plaques infiltrate but slightly into the surface. 4. Carious teeth have a different appearance. The plaques infiltrate more or less deeply. They even penetrate into the macroscopically free zones of the enamel as well as of the dentine. The infiltrate is diffuse, especially in regions where the relationship between mineral and organic constituents is distrubed.

Dental Caries↗