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Y Baba

Publications and source records attributed to Y Baba.

At least 91 records · Page 5Linked to original sources
PubMed1999

Capillary affinity gel electrophoresis: new technique for specific recognition of DNA sequence and the mutation detection on DNA.

The present state of studies on capillary affinity gel electrophoresis, which is a new technique for the specific recognition of a target DNA sequence, is reviewed. This article includes the principle, theory, methods, and applications of this technology. The great potential of capillary affinity gel electrophoresis for the sequence-specific recognition of DNA and the detection of mutations in specific genes is illustrated.

Adenine↗
PubMed1999

Unusual capillary electrophoretic behavior of triplet repeat DNA.

We investigated the electrophoretic behavior of triplet repeat DNA fragments by capillary electrophoresis and found triplet repeat DNA fragments showed unusual mobilities compared with those of commercially available DNA molecular marker. The electrophoretic data are analyzed by means of Ogston model and the mechanism of a change in mobility of triplet repeat DNA is discussed. The unusual mobilities are caused by the characteristic higher-order structure formed by GC-rich triplet repeat DNA.

DNA↗
PubMed1999

Dendritic Ca2+ transient increase evoked by wind stimulus in the cricket giant interneuron.

In vivo Ca2+ imaging was applied to the cricket median giant interneuron (MGI), to visualize the dendritic processing of mechanosensory signals. Wind stimulation (air-puff) to the cerci induced a transient increase in the cytosolic Ca2+ concentration ([Ca2+]i) in the MGI with a latency of a few seconds, suggesting the release of Ca2+ from the intracellular store site in the MGI. The amplitude of the transient increase in [Ca2+]i in the dendrites depended on the direction of the air-puff, and the increase in [Ca2+]i evoked by the air-puff was suppressed by the hyperpolarizing current injection which blocked the generation of action potentials. These results indicate that the action potential is necessary to the direction-sensitive increase in [Ca2+]i induced by wind stimulation.

Animals↗
PubMed1999

Factors that predict intrahepatic recurrence of hepatocellular carcinoma in 81 patients initially treated by percutaneous ethanol injection.

BACKGROUND: In Japan, where liver transplantation has not been used to treat patients with hepatocellular carcinoma (HCC), percutaneous ethanol injection (PEI) has been employed for those with small HCCs that are not amenable to surgical resection. In the current study, the authors evaluated PEI as a treatment for HCC patients by studying recurrence rates and survival after treatment. They then examined the clinicopathologic factors that predicted patterns of local and distant intrahepatic recurrence. METHODS: For 81 patients who underwent PEI as initial therapy between 1990 and 1997, the cumulative recurrence and survival rates and their correlations with 16 clinicopathologic factors were studied using the Kaplan-Meier method. RESULTS: The 3-year overall cumulative rates of intrahepatic recurrence and survival were 81% and 84%, respectively. At the end of the observation period, intrahepatic recurrence was detected in 56 patients (69%). In 21 (38%) of 56 patients, local recurrences were significantly associated with earlier stages of underlying cirrhosis, decreased indocyanine green retention at 15 minutes (ICG R15), larger tumor size, and histologically advanced tumor grade. Distant intrahepatic recurrence was also significantly associated with liver function and ICG R15. CONCLUSIONS: PEI is most effective as the initial treatment for patients with well-differentiated HCC when the tumor is less than 15 mm in greatest dimension. However, local recurrence depends predominantly on the biologic characteristics of the tumor, regardless of the efficacy of PEI. Surgical resection of HCC should be considered, especially for patients with mild liver dysfunction.

Aged↗
PubMed1999

Identification of the SH2 domain binding protein of Bruton's tyrosine kinase as BLNK--functional significance of Btk-SH2 domain in B-cell antigen receptor-coupled calcium signaling.

Bruton's tyrosine kinase (Btk) is a critical component in the B-cell antigen receptor (BCR)-coupled signaling pathway. Its deficiency in B cells leads to loss or marked reduction in the BCR-induced calcium signaling. It is known that this BCR-induced calcium signaling depends on the activation of phospholipase Cgamma (PLCgamma), which is mediated by Btk and another tyrosine kinase Syk and that the SH2 and pleckstrin homology (PH) domains of Btk play important roles in this activation process. Although the importance of the PH domain of Btk has been explained by its role in the membrane targeting of Btk, the functional significance of the SH2 domain in the calcium signaling has remained merely a matter of speculation. In this report, we identify that one of the major Btk-SH2 domain-binding proteins in B cells is BLNK (B-cell linker protein) and present evidences that the interaction of BLNK and the SH2 domain of Btk contributes to the complete tyrosine phosphorylation of PLCgamma.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1999

Bruton's tyrosine kinase activity is negatively regulated by Sab, the Btk-SH3 domain-binding protein.

Bruton's tyrosine kinase (Btk) is a cytoplasmic tyrosine kinase that is crucial for human and murine B cell development, and its deficiency causes human X-linked agammaglobulinemia and murine X-linked immunodeficiency. In this report, we describe the function of the Btk-binding protein Sab (SH3-domain binding protein that preferentially associates with Btk), which we reported previously as a newly identified Src homology 3 domain-binding protein. Sab was shown to inhibit the auto- and transphosphorylation activity of Btk, which prompted us to propose that Sab functions as a transregulator of Btk. Forced overexpression of Sab in B cells led to the reduction of B cell antigen receptor-induced tyrosine phosphorylation of Btk and significantly reduced both early and late B cell antigen receptor-mediated events, including calcium mobilization, inositol 1, 4,5-trisphosphate production, and apoptotic cell death, where the involvement of Btk activity has been demonstrated previously. Together, these results indicate the negative regulatory role of Sab in the B cell cytoplasmic tyrosine kinase pathway.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Involvement of wiskott-aldrich syndrome protein in B-cell cytoplasmic tyrosine kinase pathway.

Bruton's tyrosine kinase (Btk) has been shown to play a role in normal B-lymphocyte development. Defective expression of Btk leads to human and murine immunodeficiencies. However, the exact role of Btk in the cytoplasmic signal transduction in B cells is still unclear. This study represents a search for the substrate for Btk in vivo. We identified one of the major phosphoproteins associated with Btk in the preB cell line NALM6 as the Wiskott-Aldrich syndrome protein (WASP), the gene product responsible for Wiskott-Aldrich syndrome, which is another hereditary immunodeficiency with distinct abnormalities in hematopoietic cells. We demonstrated that WASP was transiently tyrosine-phosphorylated after B-cell antigen receptor cross-linking on B cells, suggesting that WASP is located downstream of cytoplasmic tyrosine kinases. An in vivo reconstitution system demonstrated that WASP is physically associated with Btk and can serve as the substrate for Btk. A protein binding assay suggested that the tyrosine-phosphorylation of WASP alters the association between WASP and a cellular protein. Furthermore, identification of the phosphorylation site of WASP in reconstituted cells allowed us to evaluate the catalytic specificity of Btk, the exact nature of which is still unknown.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1999

Interferon-gamma inhibits the myofibroblastic phenotype of rat palatal fibroblasts induced by transforming growth factor-beta1 in vitro.

Interferon-gamma (IFN-gamma), a multifunctional cytokine, has been noted as a potential therapeutic agent for various fibrotic disorders, including excessive scar tissue formation. We previously reported that transforming growth factor-beta1 (TGF-beta1) induced the myofibroblastic phenotype in palatal fibroblasts derived from palatal mucosa, and that such effects might have a close link to palatal scar formation. In the present study, we examined the effects of IFN-gamma on TGF-beta1-pretreated palatal fibroblasts for the purpose of clarifying the suppressive potency against myofibroblastic phenotype expression in vitro. IFN-gamma significantly altered the spindle morphology of TGF-beta1-pretreated palatal fibroblasts into the polygonal one that was similar to the non-treated palatal fibroblasts. This change was parallel with a decrease in the expression of alpha-smooth muscle actin protein, a marker for myofibroblast, as determined by immunoblot analysis. Northern blot analysis showed that IFN-gamma inhibited proalpha2(I) collagen mRNA expression that was stimulated by TGF-beta1 pretreatment for 24 h. Furthermore, IFN-gamma decreased the cell contractility enhanced by TGF-beta1 pretreatment for 24 h in a three-dimensional collagen gel culture system. These results suggest that IFN-gamma may have negative effects with regard to controlling the myofibroblastic phenotype induced by TGF-beta1 in palatal fibroblasts.

Actins↗
PubMed1999

Tranilast inhibits the proliferation of human coronary smooth muscle cell through the activation of p21waf1.

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) occurs due to vascular smooth muscle cell proliferation and migration. Recently, tranilast, an anti-allergic drug, has been used for the prevention of restenosis after PTCA. To determine the molecular mechanism involved, the effect of tranilast on the proliferation of human coronary smooth muscle cells (SMCs) was investigated. Tranilast arrested the proliferation of human coronary SMCs at the G0/G1 phase of the cell cycle. In association with this inhibitory effect, tranilast increased p21waf1 and p53 tumor suppressor factor, and decreased cyclin-dependent kinase 2 (CDK2) activity. These results suggest that tranilast inhibits the proliferation of human coronary SMCs during restenosis after PTCA via an induction of p21waf1 and p53. Tranilast may thus allow us to prevent restenosis after PTCA by interfering with this mechanism.

Anti-Allergic Agents↗
PubMed1999

Ipecac alkaloids from Cephaelis acuminata.

From the dried roots of Cephaelis acuminata, five ipecac alkaloids, neocephaeline, 7'-O-demethylcephaeline, 10-O-demethylcephaeline, 2'-N-(1"-deoxy-1"-beta-D-fructopyranosyl)cephaeline and 2'-N-(1"-deoxy-1"-beta-D-fructopyranosyl)neocephaeline, were isolated, along with emetine, cephaeline, psychotrine, protoemetine, 9-demethylprotoemetinol and isocephaeline. Structures were determined by spectroscopic and chemical means.

Ipecac↗
PubMed1999

Quantitative analysis of interleukin 6 (IL-6) in patients with IgA nephropathy after tonsillectomy.

The biological response to tonsillectomy was studied in 21 patients suffering from chronic tonsillitis with or without IgA nephropathy (IgAN). Serum and urinary interleukin-6 (IL-6) levels were measured before and after tonsillectomy. Serum IL-6 levels in case of IgAN peaked 3 h after tonsillectomy and more rapidly than control cases. No significant differences were observed between two cases through the time. Urinary IL-6 levels were significantly higher before and at 6 and 48 h after tonsillectomy in IgAN cases. Stimulation of tonsils caused serum IL-6 elevation and changes in urinary IL-6 levels in IgAN cases. Elevation of urinary IL-6 levels after tonsillectomy in patients with IgAN may reflect an increase in the production of IL-6 in the kidneys. Measurement of urinary IL-6 levels after tonsillectomy is useful to elucidate the efficacy of tonsillectomy in IgAN patients.

Adolescent↗
PubMed1999

Direct measurement of DNA by means of AFM.

We have demonstrated that the electrostatic stretch-and-positioning method is useful for the analysis of a long DNA molecule by means of atomic force microscopy (AFM). DNA molecules were stretched parallel to the field line, and immobilized onto the aluminum electrodes patterned on a glass plate. Through AFM observation, we confirmed the immobilization of individual DNA molecules, not aggregate.

Bacteriophage lambda↗
PubMed1999

DNA analysis by microfabricated capillary electrophoresis device.

The LIGA (Lithographie Galvanoformung Abformung) process using synchrotron radiation lithography is applied to the microfabrication of capillary array electrophoresis (CAE) device. Laser-induced fluorescence detection system for the CAE device has been constructed by the modification of laser confocal fluorescence microscopy. DNA molecules were detected during migrating in the microchannels filled with polymer separation matrices under electric field to optimize the separation conditions for DNA analysis. Based on this observation, we demonstrated that microfabricated CAE device is realized the fast separation of DNA.

DNA↗
PubMed1999

Dynamic magnetic resonance imaging of head and neck lesions.

Dynamic magnetic resonance imaging (MRI) has been used to improve the detection of tumors, to determine the tumor extension, and to make differential diagnosis. Most malignant lesions of the head and neck show early enhancement and early washout of contrast media on dynamic MRI, but the tumor characterization remains unclear. Pharmacokinetic analysis of dynamic MRI can provide information about the permeability of Gd-DTPA in the tumor that may reflect the oxygen concentration of the tumor and the amount of drug delivered to the tumor. This information may be useful in the prediction of radiation and/or chemotherapy response of the tumor.

Algorithms↗
PubMed1999

[The incidences of virulence genes in Escherichia coli strains from sporadic diarrheal children].

To investigate the incidence of diarrheagenic Escherichia coli among E. coli strains screened by commercially available O-antigen antisera, we used PCR to isolate 8 virulence genes (eae, bfpA, IpaH, LT, ST, VT1, VT2, and aggR) in 184 E. coli strains sampled from sporadic diarrheal children in our district. eae and bfpA are the localized adherence factor genes of enteropathogenic E. coli (EPEC). IpaH is the invasion antigen gene of enteroinvasive E. coli (EIEC), LT and ST are the toxin genes of enterotoxigenic E. coli (ETEC), VT1 and VT2 are the toxin genes of enterohemorrhagic E. coli (EHEC), and aggR is the adherence factor gene of enteroaggregative E. coli (EAggEC). The results were as follows: eae, 7 (3.8%); bfpA, 0 (0%); IpaH, 0 (0%); LT, 0 (0%); ST, 2 (1.1%); VT, 5 (2.7%); aggR, 8 (4.3%). Seven isolates with eae did not have bfpA, and did not show a localized adherence to HeLa cells. Seven of the 8 isolates with aggR showed aggregative adherence to HeLa cells, while their O-serotypes of them were O111:H21 or O111:HUT. Because of the low incidence of the virulence gene, the commercially available O-antigen antisera was not expected to be useful for the screening of diarrheagenic E. coli, except for EHEC and EAggEC. EAggEC may be important as a pathogen of sporadic diarrhea of children as well as EHEC.

Child↗