Search PubMed⌕ Search

Biomedical subjects

S Ota

Publications and source records attributed to S Ota.

At least 73 records · Page 4Linked to original sources
PubMed1999

Cloning and characterization of a novel Rab-family gene, Rab36, within the region at 22q11.2 that is homozygously deleted in malignant rhabdoid tumors.

Malignant rhabdoid tumors (MRTs) are rare, pediatric soft-tissue tumors. Homozygous deletions at chromosome 22q11.2 are a recurrent cytogenetic characteristic of MRTs, an indication that this locus may harbor one or more genes conferring tumor-suppressor activity. We constructed a deletion map of the relevant part of 22q11.2 from a panel of seven MRT cell lines, and isolated a novel gene from the center of the region. As it showed a high degree of sequence homology to genes of the Rab family, we designated it Rab36. The protein encoded by Rab36 was localized at the Golgi body. Sequencing of Rab36 cDNAs from three cell lines that retained at least one allele of this gene revealed no nonsense or frameshift mutations. Experiments to induce over-expression of Rab36 by transfection to an MRT cell line similarly failed to justify designation of this gene as a tumor suppressor that would contribute to tumorigenesis by a loss-of-function mechanism.

Amino Acid Sequence↗
PubMed1999

Endoscopic variceal ligation is a sufficient procedure for the treatment of oesophageal varices in patients with hepatitis C liver cirrhosis: comparison with injection sclerotherapy.

AIMS: Endoscopic variceal ligation (EVL) is a recently developed alternative to endoscopic injection sclerotherapy (EIS) for the treatment of oesophageal varices. Endoscopic variceal ligation and EIS were compared in an attempt to clarify the efficacy and safety of EVL for patients with cirrhosis due to hepatitis C. METHODS: Endoscopic variceal ligation was performed in 60 patients and EIS in 30. Varices were eradicated in all patients by EVL and 87% (26 out of 30) by EIS. RESULTS: There was no significant difference between EVL and EIS in relation to the incidence of bleeding and the 5 year survival rate after treatment. There were no severe complications except mild substernal pain after EVL, while pulmonary embolism occurred in one patient receiving EIS. CONCLUSIONS: Endoscopic variceal ligation is a safe and effective technique for eradicating oesophageal varices in patients with hepatitis C cirrhosis.

Esophageal and Gastric Varices↗
PubMed1999

Massive gastrointestinal hemorrhage in systemic lupus erythematosus: successful treatment with corticosteroid pulse therapy.

Although mesenteric vasculitis due to systemic lupus erythematosus (SLE) is relatively uncommon, it is the most dangerous manifestation associated with high mortality. We describe the case of a SLE patient with life-threatening gastrointestinal hemorrhage due to mesenteric vasculitis in whom methylprednisolone pulse therapy was quite effective in controlling the hemorrhage and resulted in a satisfactory long term outcome. A 47-yr-old woman presenting with high fever, rash, and melena was diagnosed with SLE from positive antinuclear antibodies, anti-dsDNA, and low complement titers. Although fever and rash subsided with administration of prednisolone, massive hematemesis appeared with melena. Endoscopy demonstrated bleeding ulceration of the antrum, which was intractable despite intensive antiulcer therapy and transfusion. Surgical exploration revealed ileal penetration, and multiple bleeding ulcerations were observed over the resected ileum as well as the antral ulceration. However, bleeding persisted after surgery and surgical findings prompted us to select methylprednisolone pulse. Hemorrhage responded promptly to the therapy, and the patient has remained well since then for >10 yr. Our report indicates that corticosteroid pulse may serve as one of the therapeutic options for SLE with massive hemorrhage due to widespread mesenteric vasculitis.

Anti-Inflammatory Agents↗
PubMed1999

A new quantitative method for rabies virus by detection of nucleoprotein in virion using ELISA.

We have developed a new quantitative method for rabies virus (RV) detection using enzyme-linked immunosorbent assay (ELISA). The method named N-ELISA was based on the quantitation of nucleoprotein (N) in RV virions captured by RV-specific polyclonal antibodies on an ELISA plate. Both infective and defective interfering (DI) particles of RV could be detected by this method. When viruses were propagated in a medium of pH 7.4 adjusted with 7% NaHCO3, N-ELISA could detect them with titers of more than 10(6) pfu/ml, though the result did not correlate highly with that of the infectivity assay. The reason for this was considered to be that RVs included spikeless and damaged particles which were produced under conditions of low or high pH. However, in the time course of virus yield, titers of N-ELISA correlated well with those of the infectivity assay.

Animals↗
PubMed1999

[Screening of prostate cancer with PSA and transperineal six sextant biopsy].

OBJECT: The objectives of this study are to examine how many cancer patients we can detect among the outpatients whose PSA values are above 4.0 ng/ml, and to compare the usefulness of transperineal six sextant biopsy (ss-biopsy) with that of transrectal one. METHODS: All the male outpatients (above 50 years old) were inspected Tandem-R PSA levels and digital rectal examination (DRE). Among them, 129 patients showed more than 4.0 ng/ml of PSA values and/or positive finding of DRE, and underwent subsequent transperineal ss-biopsy. RESULTS: Cancers were detected in 52 patients (40.3%) without major complications. Among 64 gray zone (PSA 4.1-10.0 ng/ml) patients, 17 (26.6%) were found to be cancer by ss-biopsy, meanwhile only 2 cancer patients (8.9%) were detected from 23 gray zone ones by traditional directed biopsy. Application of PSA density could not be found practicable to eliminate unnecessary biopsies in the gray zone group. CONCLUSION: Prostate cancer could be found nearly a fourth in the gray zone group of the outpatients. To enhance the detection rate, obtaining at least 6 core samples are recommended from either perineal or rectal root.

Aged↗
PubMed1998

Phosphorylation of CrkII adaptor protein at tyrosine 221 by epidermal growth factor receptor.

CrkII adaptor protein becomes tyrosine-phosphorylated upon various types of stimulation. We examined whether tyrosine 221, which has been shown to be phosphorylated by c-Abl, was phosphorylated also by other tyrosine kinases, such as epidermal growth factor (EGF) receptor. For this purpose, we developed an antibody that specifically recognizes Tyr221-phosphorylated CrkII, and we demonstrated that CrkII was phosphorylated on Tyr221 upon EGF stimulation. When NRK cells were stimulated with EGF, the tyrosine-phosphorylated CrkII was detected at the periphery of the cells, where ruffling is prominent, suggesting that signaling to CrkII may be involved in EGF-dependent cytoskeletal reorganization. The EGF-dependent phosphorylation of CrkII was also detected in a c-Abl-deficient cell line. Moreover, recombinant CrkII protein was phosphorylated in vitro by EGF receptor. These results strongly suggest that EGF receptor directly phosphorylates CrkII. Mutational analysis revealed that the src homology 2 domain was essential for the phosphorylation of CrkII by EGF receptor but not by c-Abl, arguing that these kinases phosphorylate CrkII by different phosphorylation mechanisms. Finally, we found that the CrkII protein phosphorylated upon EGF stimulation did not bind to the phosphotyrosine-containing peptide and that CrkII initiated dissociation from EGF receptor within 3 min even with the sustained tyrosine phosphorylation of EGF receptor. This result implicated phosphorylation of Tyr221 in the negative regulation of the src homology 2-mediated binding of CrkII to EGF receptor.

Animals↗
PubMed1998

Monoclonal origin of an esophageal carcinosarcoma producing granulocyte-colony stimulating factor: a case report.

BACKGROUND: Carcinosarcomas are comprised of carcinomatous and sarcomatous elements, and their histogenesis remains unclear. The authors examined the serum concentrations of hematopoietic growth factors and performed immunohistochemical studies on an esophageal carcinosarcoma from a patient with marked granulocytosis to determine its histopathogenesis and clonality. METHODS: The authors examined the case of a 63-year-old man with a polypoid tumor of the esophagus associated with marked leukocytosis (131 x 10(9) per liter). Immunohistochemical staining of the esophageal tumor was performed using monoclonal antibodies against granulocyte-colony stimulating factor (G-CSF), keratin, epithelial membrane antigen (EMA), and vimentin. RESULTS: The patient's leukocyte count was increased (124 x 10(9) per liter) on admission. Because mature granulocytes predominantly were increased despite the absence of apparent infection, the patient's serum G-CSF concentration was examined and found to be 286.0 pg/mL and to increase with time. After thoracic esophagectomy was performed, granulocyte count and serum G-CSF concentration rapidly normalized. G-CSF concentration was 50-fold higher in the tumor tissue extract than in the extract from normal esophageal tissue. Microscopic examination of the resected specimens revealed that the tumor was comprised of squamous cell carcinoma (SCC) and spindle-shaped sarcomatous elements, and transitional features were observed within these two components. Immunohistochemical examination disclosed cells that were positive for keratin and EMA in the carcinomatous element and vimentin positive cells in the sarcomatous element. However, both types of tumor cells were positive for G-CSF. CONCLUSIONS: The presence of G-CSF in both SCC cells and spindle-shaped sarcomatous cells indicated that these two components originated from a single clone.

Carcinosarcoma↗
PubMed1998

NRP/B, a novel nuclear matrix protein, associates with p110(RB) and is involved in neuronal differentiation.

The nuclear matrix is defined as the insoluble framework of the nucleus and has been implicated in the regulation of gene expression, the cell cycle, and nuclear structural integrity via linkage to intermediate filaments of the cytoskeleton. We have discovered a novel nuclear matrix protein, NRP/B (nuclear restricted protein/brain), which contains two major structural elements: a BTB domain-like structure in the predicted NH2 terminus, and a "kelch motif" in the predicted COOH-terminal domain. NRP/B mRNA (5.5 kb) is predominantly expressed in human fetal and adult brain with minor expression in kidney and pancreas. During mouse embryogenesis, NRP/B mRNA expression is upregulated in the nervous system. The NRP/B protein is expressed in rat primary hippocampal neurons, but not in primary astrocytes. NRP/B expression was upregulated during the differentiation of murine Neuro 2A and human SH-SY5Y neuroblastoma cells. Overexpression of NRP/B in these cells augmented neuronal process formation. Treatment with antisense NRP/B oligodeoxynucleotides inhibited the neurite development of rat primary hippocampal neurons as well as the neuronal process formation during neuronal differentiation of PC-12 cells. Since the hypophosphorylated form of retinoblastoma protein (p110(RB)) is found to be associated with the nuclear matrix and overexpression of p110(RB) induces neuronal differentiation, we investigated whether NRP/B is associated with p110(RB). Both in vivo and in vitro experiments demonstrate that NRP/B can be phosphorylated and can bind to the functionally active hypophosphorylated form of the p110(RB) during neuronal differentiation of SH-SY5Y neuroblastoma cells induced by retinoic acid. Our studies indicate that NRP/B is a novel nuclear matrix protein, specifically expressed in primary neurons, that interacts with p110(RB) and participates in the regulation of neuronal process formation.

Adult↗
PubMed1998

Nonsteroidal anti-inflammatory drugs may delay the repair of gastric mucosa by suppressing prostaglandin-mediated increase of hepatocyte growth factor production.

Prostaglandins (PGs), hepatocyte growth factor (HGF), and induction of cyclooxygenase (PG synthetase, COX) play important roles in the repair process of gastric mucosa. We hypothesized that nonsteroidal anti-inflammatory drugs (NSAIDs), including indomethacin (IND), retard the healing of ulcers by suppressing these factors. In this study, we investigated the effects of cytokines, growth factors, and IND on production of PG and HGF, and induction of COX using cultured human gastric fibroblasts. Exogenous PGs significantly increased HGF production in a dose-dependent manner. Among various potential stimulants tested, interleukin-1 beta (IL-1 beta) dramatically increased PGE2 production and significantly stimulated HGF production. IL-1 beta induced COX-2 but not COX-1 protein. IND significantly reduced both basal and IL-1 beta-induced PGE2 release and HGF production. These results suggest that the IL-1 beta-PG-HGF pathway plays a role in the repair process of gastric mucosa. Further, NSAIDs may delay the healing of gastric mucosal ulcer, in part through suppression of HGF expression via inhibition of endogenous PG production.

Alprostadil↗
PubMed1998

Regulation of cyclin D-dependent kinase activity in rat liver regeneration.

The regulation of cyclin D-dependent kinase activity in tissue regeneration in vivo has not been fully described. In young adult rat liver after 70% partial hepatectomy, the association of cyclin D1 with cdk4 was significantly promoted during G1 phase and was maximal at 18 hr, corresponding mainly to late G1. Cyclin D1-dependent kinase activity also strongly increased during G1 phase. The timing of the induction of cyclin D1 / cdk4 complex assembly correlated well with that of cyclin D1-dependent kinase activity. At 18 hr after partial hepatectomy, the amounts of CDK inhibitors p21(CIP1) and p27(KIP1) were also maximal, while only one-tenth of p21(CIP1) and of p27(KIP1) was associated with cyclin D1. These findings suggest that cyclin D1, cdk4 and their association act as promoting factors, and that both p21(CIP1) and p27(KIP1) may have physiological functions as adaptor proteins in additions to their roles as CDK inhibitors in rat liver regeneration.

Animals↗
PubMed1998

Hepatocyte growth factor accelerates restitution of intestinal epithelial cells.

Many cytokines are involved in the repair of damaged tissue, and one of these, hepatocyte growth factor (HGF), is involved not only with liver regeneration but also in the repair of other tissues. To investigate the importance of HGF in the repair of the small intestine, we evaluated its effect and that of other growth factors in IEC-6 cells, an intestinal epithelial cell line derived from normal rat small intestine. Round "wounds" were made in confluent monolayers of IEC-6 by silicon rubber-tipped steel rods and various cytokines; transforming growth factor alpha (TGF-alpha), transforming growth factor beta1 (TGF-beta1), keratinocyte growth factor (KGF), and HGF, were added. We photographed the repaired monolayers every 24 h and calculated the ratios of areas not covered by cells to initial areas. Cell proliferation with TGF-alpha, TGF-beta, KGF, or HGF was examined in terms of [3H]-thymidine uptake. Finally, we determined c-met (the HGF receptor) mRNA in the IEC-6 cells by Northern blot hybridization. HGF was the most potent of the cytokines in accelerating repair of the damaged monolayer of IEC-6. HGF was also 1.34 times more effective than control the medium for inducing cell proliferation of IEC-6. By Northern blot hybridization, three bands of mRNA bound to c-met cDNA. These results suggest that HGF is important in the repair of the small intestine.

Animals↗
PubMed1998

Soluble interleukin-2 receptor in children with reflux nephropathy.

PURPOSE: Serum soluble interleukin-2 receptor level is a sensitive and quantitative marker of lymphocyte activation. We determined levels of serum soluble interleukin-2 receptor in children with reflux nephropathy to evaluate its clinical significance in the prediction for the progression of renal injuries. MATERIALS AND METHODS: Serum soluble interleukin-2 receptor values were determined in 63 children with reflux nephropathy. The group consisted of 37 boys and 26 girls 10 to 18 years old. T cells (naive and memory), B cells and macrophages were evaluated immunohistochemically in the scarred kidneys of 4 other patients (3 boys and 1 girl 5 to 16 years old) who underwent nephrectomy due to severe reflux nephropathy with little function seen on (99m)technetium-dimercapto-succinic acid (DMSA) renal scan. Levels of serum soluble interleukin-2 receptor were measured by an enzyme-linked immunosorbent assay. We simultaneously determined serum levels of creatinine and beta2-microglobulin, and urinary levels of alpha1-microglobulin and microalbumin. Individual functions of the right and left kidneys were estimated by renal dimercaptosuccinic acid uptake. RESULTS: Levels of serum soluble interleukin-2 receptor in the patients who had low total uptake of DMSA (right uptake plus left uptake) were significantly higher than those from patients with normal total uptake. Levels of serum soluble interleukin-2 receptor correlated significantly with levels of creatinine (r=0.616, p <0.0001) and beta2-microglobulin (r=0.803, p <0.0001), and levels of urinary alpha1-microglobulin (r=0.753, p <0.0001) and microalbumin (r=0.673, p <0.0001). A significant negative correlation was observed between levels of serum soluble interleukin-2 receptor and total DMSA uptake values (right uptake plus left uptake r=-0.678, p <0.0001). In the scarred kidneys leukocyte infiltrates were markedly increased in fibrosed spaces. The predominant cell type in these lesions was memory T cells. CONCLUSIONS: These results suggest that elevated levels of serum soluble interleukin-2 receptor are likely to reflect activated T cells in the kidneys of patients with reflux nephropathy and may be a useful predictor of progression of renal injury in these children.

Adolescent↗
PubMed1998

Enzymatic analysis of acetylpolyamine.

An enzymatic method was proposed for measuring acetylpolyamine (AcPA) alone, even when non-acetylated polyamine co-exists. The method consisted of four enzymatic reactions. First, AcPA was hydrolysed by acylpolyamine amidohydrolase to yield acetate; followed by the other three reactions coupled with three enzymes, respectively, acetate kinase, pyruvate kinase, and lactate dehydrogenase; the acetate formation caused a decrease in NADH. The quantity of AcPA was then evaluated as the change in absorbance at 340 nm. The reagent composition of the reaction mixture was determined, and characteristics of the method were investigated. The validation tests produced satisfactory results. The co-existence of non-acetylated polyamine gave no effect on the measurement. The present method was found to be used easily, rapidly and reliably for the selective determination of AcPA itself.

Acetate Kinase↗
PubMed1998

Constitutive association of EGF receptor with the CrkII-23 mutant that inhibits transformation of NRK cells by EGF and TGF-beta.

Crk belongs to the adapter proteins that participate in many signalling pathways from cell surface receptors. We have characterised the CrkII-23 mutant that inhibits the transformation of NRK cells induced by epidermal growth factor (EGF) and transforming growth factor (TGF)-beta. To study the biochemical difference, cDNAs of the wild-type CrkII and the CrkII-23 mutant were introduced stably into NIH 3T3 cells expressing EGF receptor (EGFR). Both CrkII and CrkII-23 were phosphorylated on tyrosine upon EGF simulation with similar time course and dose dependency. Whereas the wild-type CrkII bound to EGFR only after EGF stimulation, CrkII-23 bound to EGFR from before stimulation. Mutation in the Src homology (SH) 2 or amino-terminal SH3 domain did not abolish the binding of CrkII-23 to EGFR in the quiescent cells, suggesting that the binding is mediated by a novel mechanism. These CrkII-23-derived mutants, however, did not suppress transformation of NRK cells by EGF and TGF-beta. Hence, both the SH2 and amino-terminal SH3 domains are required to inhibit transformation of NRK cells. These results suggest that persistent signalling from CrkII-23 bound to EGFR suppresses transformation by EGF and TGF-beta in NRK23 cells.

3T3 Cells↗
PubMed1998

A carrier for clinical use of recombinant human BMP-2: dehydrothermally cross-linked composite of fibrillar and denatured atelocollagen sponge.

The clinical applicability of a dehydrothermally cross-linked composite of fibrillar and denatured atelocollagen sponge (DCFD-AS), as a carrier of recombinant human bone morphogenetic protein-2 (rhBMP-2) was evaluated in the rat subcutaneous pouch. After four weeks, DCFD-AS with rhBMP-2 formed compact bone, without undergoing significant changes in shape and size, by means of intramembranous ossification. The ultimate size, shape and location of induced new bone was accurately controlled by the carrier. Low antigenicity of soluble atelocollagen, cross-linking without chemicals, the combination of gelatin with fibrillar collagen, and the spongy structure probably all contributed to new bone formation through intramembranous ossification without inducing an inflammatory response. Atelocollagen sponge is easily sterilized, can be stored at room temperature, and can act as a rhBMP-2 carrier without the need for complex procedures.

Animals↗
PubMed1998

Endoscopic ligation for non-esophageal variceal upper gastrointestinal hemorrhage.

BACKGROUND: Endoscopic ligation can be used for bleeding lesions in non-fibrotic tissue; however, only small numbers of patients with non-esophageal variceal upper gastrointestinal hemorrhage have been treated in this way. To evaluate the utility of the technique, we performed the procedure to treat hemorrhage not from esophageal varices during emergency endoscopy. PATIENTS AND METHODS: Bleeding was identified from gastric Dieulafoy's ulcers (n=4), duodenal ulcers (n=3), gastric angiodysplasia (n=2) and Mallory-Weiss tears (n=3). The bleeding points were aspirated and controlled by endoscopic ligation and complete hemostasis was achieved in all cases. RESULTS: Although these lesions were located in difficult areas where endoscopic injection therapy and clipping sometimes fail, endoscopic ligation was performed easily and effectively without complications. Six of the patients had severe underlying disease, including acute and chronic myelogenous leukemia, liver cirrhosis and chronic renal failure; none suffered deterioration in their general condition after endoscopic ligation. CONCLUSIONS: Our findings suggest that endoscopic ligation is an easy and effective method of treatment for patients with gastrointestinal hemorrhage not from esophageal varices, and is safe even in patients with poor general health.

Adult↗
PubMed1998

Follow-up of improvement in regional cerebral blood flow and mental status in Alzheimer's disease: a case report.

Cerebral SPECT imaging has the potential to make important contributions in the follow-up care of patients with Alzheimer's disease. An unusual case of a patient who showed a follow-up cerebral blood flow pattern different from that routinely seen in Alzheimer's disease patients is reported here. Qualitative and voxel-based objective evaluation of follow-up scans revealed improvement in parietotemporal deficits that had been observed on a baseline study. This change was observed without significant further deterioration in ratings by dementia batteries. This case shows that a baseline regional cerebral blood flow study might be necessary for reference and comparison in the proper follow-up care of Alzheimer's disease patients.

Aged↗