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Biomedical subjects

Y Baba

Publications and source records attributed to Y Baba.

At least 19 recordsLinked to original sources
PubMed2000

Fast separation of oligonucleotide and triplet repeat DNA on a microfabricated capillary electrophoresis device and capillary electrophoresis.

A laser-induced fluorescence detection system coupled with a highly sensitive silicon-intensified target (SIT) camera is successfully applied to the imaging of a band for DNA fragment labeling by fluorescence dye in a microchannel, and to the visualizing of the separation process on a microfabricated chip. We demonstrated that an only 6 mm separation channel is sufficient for the separation of triplet repeat DNA fragment and DNA molecular marker within only 12 s. The separation using the microfabricated capillary electrophoresis device is confirmed to be at least 18 times faster than the same separation carried out by conventional capillary electrophoresis with 24.5 cm effective length. The use of a short capillary with 8.5 cm effective length is also efficient for fast separation of DNA; however, the microchip technology is even faster than capillary electrophoresis using a short capillary.

DNA↗
PubMed2000

The role of endoscopic retrograde cholangiopancreatography in infants with cholestasis.

BACKGROUND/PURPOSE: Endoscopic retrograde cholangiopancreatography (ERCP) was assessed in the diagnosis of cholestatic liver disease in infants. METHODS: ERCP was performed in 50 infants who had prolonged cholestasis. Their ages ranged from 25 to 274 days (mean, 69 days), and their weight ranged from 2.6 to 6.7 kg (mean, 4.7 kg). Incomplete visualization of the biliary tree or visualization of only the pancreatic duct was followed by exploratory laparotomy. In those in whom the biliary tree was visualized completely, the caliber of the bile duct was compared with that of the pancreatic duct. RESULTS: ERCP was completed in 43 patients (success rate, 86%) without complications. In the 7 patients in whom ERCP failed, 6 had biliary atresia (BA) diagnosed by exploratory laparotomy. The other patient had congenital biliary dilatation (CBD). In 29 of the 43 patients, the biliary tree was seen partially or only the pancreatic duct was visualized. These patients had BA diagnosed by laparotomy. Complete visualization of the biliary tree was obtained in 14 patients. Of these, 9 had neonatal hepatitis (NH), 2 had a paucity of intrahepatic bile ducts (PIBLD), and 3 had CBD. In all of the patients with NH, cholestasis improved spontaneously. The 2 patients with PIBLD had biopsy-proven disease. The caliber of the bile duct was larger than that of the pancreatic duct in NH. This relationship was not observed in PIBLD. CONCLUSIONS: ERCP is safe in infants. It is useful in the diagnosis of prolonged cholestasis.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed2000

Localization of insulinomas. Comparison of conventional arterial stimulation with venous sampling (ASVS) and superselective ASVS.

PURPOSE: To examine the value of superselective arterial stimulation venous sampling (ASVS) to localize insulinomas. MATERIAL AND METHODS: Superselective ASVS (SS-ASVS) was performed in 9 patients with insulinoma. Injection of secretagogue (calcium gluconate: 0.01 mEq Ca++/kg) was performed into the gastroduodenal, splenic (proximal and distal), and superior mesenteric arteries in 9 patients and additionally into the dorsal pancreatic artery in 6 patients. Sampling from the hepatic vein was performed to measure serum insulin concentrations at 30, 60 and 120 s after each injection of secretagogue into these arteries. SS-ASVS results were correlated with surgical findings, compared to those of conventional ASVS. RESULTS: Insulinomas were correctly localized to the head, body or tail of the pancreas by SS-ASVS in 8 patients (89%). Conventional ASVS detected insulinomas in 7 patients (78%), although it could not distinguish whether the insulinoma was located in the pancreatic body or tail in 4 of the 7 patients. There were eight-fold or more increases in serum insulin levels in hepatic venous samples related to the artery supplying the tumor in 8 patients. Localization of the insulinomas was verified at surgery in all patients. CONCLUSION: SS-ASVS is a useful method for detailed evaluation of overproduction of insulin from pancreatic insulinomas and their localization. When the pancreatic insulinoma is situated in the pancreatic body or tail, the localization is more accurately made by SS-ASVS than by conventional ASVS.

Aged↗
PubMed2000

Early glottic squamous cell carcinoma. Predictive value of MR imaging for the rate of 5-year local control with radiation therapy.

PURPOSE: To evaluate MR findings in early (T1 and T2 stages) glottic carcinomas and the predictive value of MR imaging for the rate of 5-year local control with radiation therapy. MATERIAL AND METHODS: Eighty-three patients with early glottic carcinomas were prospectively examined with MR at 1.5 T. MR investigation included unenhanced T1-weighted, T2-weighted, dynamic and contrast-enhanced T1-weighted images. Three patients with presumed advanced diseases on MR were initially treated with total laryngectomy and were excluded from the study. The remaining 80 patients were treated with radiation therapy with curative intent. Tumor detectability, size and relationship to the thyroid cartilage were determined on MR images. The MR findings were then correlated with the rate of local control. RESULTS: Forty-eight of 80 lesions (60%) were detected on MR imaging. All detected lesions but 1 demonstrated increased signal on T2-weighted images. The lesions were best delineated on dynamic images (statistically significant). The 5-year local control rate with radiation therapy was 72%. Univariate analysis revealed clinical T stage, MR detectability, tumor size and relationship to the thyroid cartilage as significant predictors. Multivariate analysis revealed that the relationship to the thyroid cartilage was an independent factor. CONCLUSION: MR provides prognostic information about the results of definitive radiation therapy. To evaluate the tumor extension in lesions detected on precontrast MR images, contrast-enhanced dynamic images should be obtained.

Adult↗
PubMed2000

[Percutaneous mechanical thrombectomy for thrombosed vessels with a hydrolyser (hydrodynamic thrombectomy catheter): clinical experience].

A hydrodynamic thrombectomy catheter was prospectively evaluated for the treatment of thrombosed vessels. Seven patients (7 males: age range from 56 to 82 years; mean age: 79 years) presenting with acute or chronic occlusion of peripheral native arteries (n = 6) and dialysis shunt (n = 1) were treated with the hydrolyser (Cordis, Johnson and Johnson, Japan). Mean occlusion time was 135 days (range: 2-300 days), and mean thrombus length 16 cm (range: 5-20 cm). Removal of the thrombus was successful in five patients (71%), regardless of the length of the thrombus. Mean procedure time was 20 minutes (range: 15-30 minutes). No major complications occurred. Adjunctive thrombolysis was required for persistence of the residual thrombosed distal vessel in one patient. Adjunctive balloon angioplasty was performed in two patients (one native vessel and one dialysis shunt), and stent placement was performed in one patient (dialysis shunt). In two unsuccessful cases, the hydrolyser could not be advanced to the distal side because of the solid thrombus. Therefore, thrombolytic therapy was chosen. However, this therapy failed because the guidewire did not pass within the thrombus. Surgery was performed in these two patients. We conclude from this clinical experience that percutaneous thrombectomy with a hydrolyser is a promising technique for the treatment of thrombosed vessels. Especially in the acute stage of thrombosed occlusion, percutaneous thrombectomy with a hydrolyser is superior to thrombectomy with a Fogarty balloon catheter because of its shorter procedure time and fewer complications.

Acute Disease↗
PubMed2000

[Giant osteoma of the temporal bone with otitis media: a case study].

A 71-year-old female presented with a giant osteoma of the right temporal bone and otitis media. Computed tomography (CT) and magnetic resonance imaging (MRI) confirmed the presence of the giant osteoma. An operation was performed to alleviate the difficult-to-treat otitis media and to address the related cosmetic problem. During the operation, three-dimensional CT (3D-CT) was very helpful in understanding the relationship between the tumor and the peripheral structures. Removal of the tumor improved the patient's otitis media. Osteoma of the temporal bone is rare. Only twenty-one cases of mastoid osteoma have been reported in Japan. In the present study, we review osteomas of the temporal bone and discuss their management.

Aged↗
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↗