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Biomedical subjects

Y Chiba

Publications and source records attributed to Y Chiba.

At least 73 records · Page 4Linked to original sources
PubMed2000

Primary aortosigmoid fistula treated by descending thoracic aortofemoral bypass.

Primary aortoenteric fistula is a rare disease with a fatal outcome unless it is diagnosed accurately and treated surgically. We present an elderly patient with primary aortosigmoid fistula confirmed by endoscopy. Descending thoracic aortofemoral bypass was performed and the aortoiliac aneurysm and sigmoid colon were then resected in continuity. The patient maintains a good quality of life 6 years after the operation with good graft patency and no sign of graft infection.

Aged↗
PubMed2000

[A case of head metastases of breast cancer successfully treated with radiation therapy and docetaxel].

A 68-year-old female underwent radical mastectomy for left breast cancer in April, 1995. She was treated with conventional combination chemotherapy (CEF) before and after surgery as an adjuvant therapy. She was treated with oral tamoxifen (TAM) and/or medroxyprogesterone (MPA) and doxifluridine daily after surgery. In May, 1998, she was found to have developed a subcutaneous tumor of the head and skull-bone, and a meningeal metastasis. We treated her with 80 mg docetaxel (TXT) one time with radiation (total dose 50 Gy), and with 70 mg two times. After the combination therapy, she achieved partial remissions of the metastases and a decrease in serum CEA. Adverse reactions to TXT were grade 3 alopecia, grade 3 to 4 neutropenia, grade 2 to 3 stomatitis, and grade 2 diarrhea. All were tolerable and reversible. The combination therapy of radiation and TXT may be a good strategy for recurrent breast cancer.

Aged↗
PubMed1999

Evidence for autoregulation of cystathionine gamma-synthase mRNA stability in Arabidopsis.

Control of messenger RNA (mRNA) stability serves as an important mechanism for regulating gene expression. Analysis of Arabidopsis mutants that overaccumulate soluble methionine (Met) revealed that the gene for cystathionine gamma-synthase (CGS), the key enzyme in Met biosynthesis, is regulated at the level of mRNA stability. Transfection experiments with wild-type and mutant forms of the CGS gene suggest that an amino acid sequence encoded by the first exon of CGS acts in cis to destabilize its own mRNA in a process that is activated by Met or one of its metabolites.

Amino Acid Sequence↗
PubMed1999

Enhanced rectal absorption of insulin-loaded Pluronic F-127 gels containing unsaturated fatty acids.

The objective of this study was to prepare and to evaluate Pluronic F-127 (PF127) gel containing unsaturated fatty acids such as oleic acid (18:1), eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6) as a potential formulation for rectal delivery of insulin. The hypoglycemic effect of insulin was examined following rectal administration of the various formulations in normal rats. Rectal insulin absorption was markedly enhanced, and marked hypoglycemia was induced by all PF127 gels (insulin dose, 5 U/kg) containing different unsaturated fatty acids. PF127 gels containing unsaturated fatty acids presented low tmax mean values indicating that the absorption of insulin occurred very rapidly in the rectum. The relative hypoglycemic efficacy of PF127 gel formulations containing fatty acids such as oleic acid, eicosapentaenoic (EPA) and docosahexaenoic (DHA) were 28.4+/-8.1, 26.8+/-14.3 and 23.1+/-5.7%, respectively. The finding demonstrated that 20% PF127 gels containing unsaturated fatty acids are potential formulations for rectal delivery of insulin.

Administration, Rectal↗
PubMed1999

Molecular and enzymic properties of recombinant 1, 2-alpha-mannosidase from Aspergillus saitoi overexpressed in Aspergillus oryzae cells.

For the construction of an overexpression system of the intracellular 1,2-alpha-mannosidase (EC 3.2.1.113) gene (msdS) from Aspergillus saitoi (now designated Aspergillus phoenicis), the N-terminal signal sequence of the gene was replaced with that of the aspergillopepsin I (EC 3.4.23.18) gene (apnS) signal, one of the same strains as described previously. Then the fused 1, 2-alpha-mannosidase gene (f-msdS) was inserted into the NotI site between P-No8142 and T-agdA in the plasmid pNAN 8142 (9.5 kbp) and thus the Aspergillus oryzae expression plasmid pNAN-AM1 (11.2 kbp) was constructed. The fused f-msdS gene has been overexpressed in a transformant A. oryzae niaD AM1 cell. The recombinant enzyme expressed in A. oryzae cells was purified to homogeneity in two steps. The system is capable of making as much as about 320 mg of the enzyme/litre of culture. The recombinant enzyme has activity with methyl-2-O-alpha-d-mannopyranosyl alpha-D-mannopyranoside at pH 5.0, while no activity was determined with methyl-3-O-alpha-D-mannopyranosyl alpha-D-mannopyranoside or methyl-6-O-alpha-D-mannopyranosyl alpha-D-mannopyranoside. The substrate specificity of the enzyme was analysed by using pyridylaminated (PA)-oligomannose-type sugar chains, Man9-6(GlcNAc)2-PA (Man is mannose; GlcNAc is N-acetylglucosamine). The enzyme hydrolysed Man8GlcNAc2-PA (type 'M8A') fastest, and 'M6C' {Manalpha1-3[Manalpha1-2Manalpha1-3(Manalpha1-6) Manalpha1-6]Manbeta1- 4GlcNAcbeta1-4GlcNAc-PA} slowest, among the PA-sugar chains. Molecular-mass values of the enzyme were determined to be 63 kDa by SDS/PAGE and 65 kDa by gel filtration on Superose 12 respectively. The pI value of the enzyme was 4.6. The N-terminal amino acid sequence of the enzyme was GSTQSRADAIKAAFSHAWDGYLQY, and sequence analysis indicated that the signal peptide from apnS gene was removed. The molar absorption coefficient, epsilon, at 280 nm was determined as 91539 M-1.cm-1. Contents of the secondary structure (alpha-helix, beta-structure and the remainder of the enzyme) by far-UV CD determination were about 55, 38 and 7% respectively. The melting temperature, Tm, of the enzyme was 71 degrees C by differential scanning calorimetry. The calorimetric enthalpy, DeltaHcal, of the enzyme was calculated as 13.3 kJ.kg of protein-1. Determination of 1 g-atom of Ca2+/mol of enzyme was performed by atomic-absorption spectrophotometry.

Amino Acid Sequence↗
PubMed1999

Tumor angiogenesis, apoptosis, and p53 oncogene in stage I lung adenocarcinoma.

The purpose of this study was to clarify which factors are important as predictors not only of patient survival but also of hematogenic metastasis in 15 patients with stage I lung adenocarcinoma who underwent curative operation. The relationship between tumor angiogenesis, apoptosis, and p53 oncogene was also studied. A total of 15 patients were divided into two groups: surviving group (n = 7) and nonsurviving (metastasis) group (n = 8). We studied the medical charts, operative records, pathologic reports, and tumor specimens taken at surgical resection. We measured the apoptotic index using the ApopTag kit and the intratumoral microvessel count using an anti-CD34 monoclonal antibody. In addition, immunohistochemical staining for the expression of p53 was conducted simultaneously. The clinicopathological characteristics, including age, sex, tumor size (pT), and histological differentiation, were not significantly different between the surviving and the nonsurviving group. The microvessel count was significantly higher in nonsurviving group than in the surviving group. The apoptotic index and the expression of p53 was not significantly different between the two groups. An inverse correlation between the apoptotic index and microvessel count, and a positive correlation between the expression of p53 and microvessel count, were observed. Angiogenesis may be an important prognostic factor in patients with stage I lung adenocarcinoma.

Adenocarcinoma↗
PubMed1999

Postoperative inflammatory reactions of impregnated Dacron grafts.

The clinical efficacy of Dacron grafts that are impregnated with collagen or gelatin has been well demonstrated, but inflammatory reactions during the first few postoperative weeks have been reported. We experienced two patients, an 87-year-old man with a reconstruction of an abdominal aorta and a 7-year-old boy with a reconstruction of aortic arch with a collagen-impregnated graft (Hemashield), who continued to demonstrate a high fever with a high serum level of C-reactive protein (CRP) and immunoglobin for more than 5 months. The body temperature, the white blood cell (WBC) counts, and the serum level of CRP were compared on the seventh and 14th postoperative day among the 37 patients who underwent a reconstruction of either a thoracic or abdominal aorta using the Hemashield graft (Hemashield group) and a nonimpregnated graft (control group) in our hospital. An elevation of body temperature above 38 degrees C was seen 29% of the patients in the Hemashield group and 0% in the control group. No significant differences were seen in the WBC counts, but the serum level of CRP was significantly higher on the 14th postoperative day in the Hemashield group. We should therefore pay careful attention to inflammatory reactions after the implantation of the impregnated grafts.

Aged↗
PubMed1999

Flow dependence and time constant of the change in nitric oxide concentration measured in the vascular media.

It has been considered that the concentration of endothelium-derived nitric oxide (NO) in the arterial vascular wall changes in response to flow-induced shear stress. In the present study, using an NO-sensitive electrode, the aim was to directly evaluate the relationship between perfusion rate and NO concentration in the arterial vascular wall. The NO microelectrode (diameter: 100 microns) was inserted into the vascular media of isolated canine femoral arteries, and the vessel was perfused with a Krebs-Henseleit buffer solution. A flow-related change in NO concentration in the vascular media was then evaluated by changing perfusion rate. NO concentration attained a peak value with a first-order time delay by a stepwise increase in perfusion rate, and the peak-level NO concentration was linearly correlated with perfusion rate in each vessel (10-154 pA at 2.1-72.3 ml min-1; n = 7, r2 = 0.89-0.99, p < 0.03). The average time constant for an increase in NO current with a stepwise increase in perfusion rate was 24 +/- 3 s (n = 5). NO production was increased by perfusing a solution containing 1 mmol l-1 L-arginine and was attenuated by 100 mumol l-1 NG-nitro-L-arginine, indicating the intactness of the endothelium, proper insertion of the NO electrode and selective detection of NO by the electrode. It is concluded that the NO microelectrode is applicable to NO measurement in the vascular media where NO controls vascular tone and that the concentration of NO in the arterial vascular media changes with perfusion rate in a rate-dependent manner as well as with a time constant of about 24 s for a stepwise increase in flow.

Animals↗
PubMed1999

Preoperative transcatheter arterial chemoembolization and prognosis of patients with hepatocellular carcinomas: retrospective analysis of 120 cases.

To clarify whether preoperative transcatheter arterial chemoembolization (TAE) improves the prognosis of patients with hepatocellular carcinoma (HCC) after surgery, 120 patients who had undergone hepatectomy for HCC from 1988 to 1994 and satisfied the criteria of stages II and III were enrolled in this study. Forty-four patients underwent preoperative TAE (group A) and 76 patients did not (group B). No significant differences in the outcomes were observed between these two groups. To rectify the comparison, patients with tumors 2 to 8 cm were assigned to groups A1 (n = 24) and B1 (n = 57), and those with tumors > 8 cm were assigned to groups A2 (n = 20) and B2 (n = 19), respectively. Although no significant differences in survival between groups A1 and B1 were found, group A2 presented superior 1-, 2-, and 3-year tumor-free survival rates of 80%, 55%, and 32% and 1-, 3-, and 5-year cumulative survival rates of 90%, 53%, and 42%. These figures are in comparison with the tumor-free survival rates of 50%, 22%, and 11% (p = 0.06), and the cumulative survival rates of 72%, 33%, and 11% (p = 0.01) during the same periods for group B2, respectively. The Cox regression model revealed that for patients with tumors > 8 cm, the relative risk of preoperative TAE for overall survival was 0.38 (p = 0.017), indicating that preoperative TAE might benefit patients with tumors > 8 cm but not those with tumors 2 to 8 cm.

Adult↗
PubMed1999

Enzyme-linked immunosorbent assay detection of prostate-specific antigen messenger ribonucleic acid in prostate cancer.

OBJECTIVES: To develop a rapid, sensitive, reverse transcriptase-polymerase chain reaction (RT-PCR) prostate-specific antigen (PSA) messenger ribonucleic acid (mRNA) detection method by applying colorimetric enzyme-linked immunosorbent assay (ELISA). METHODS: Total RNA was extracted from 16 urogenital cancer cells (including PSA-producing LNCaP cells) from pelvic and inguinal lymph node aspiration biopsy samples from patients with prostate, bladder, and penile cancer, as well as from blood samples of 500 patients with urogenital cancer. We used rTth polymerase for RT and PCR. The RNA target was amplified by RT-PCR with dinitrophenyl-labeled primer. The PCR product was denatured and hybridized on a PSA-specific probe-coated microwell plate. RESULTS: In 1 6 cancer cell lines, only LNCaP cells expressed especially high PSA mRNA values, with an optical density (OD) greater than 3. In other cell lines, two testicular cells had relatively high ODs, 1.909 and 0.987, respectively. A high PSA mRNA value was obtained by fine needle aspiration from pelvic lymph node specimens of cytologically positive lymph nodes from patients with prostate cancer but not from patients with cytologically proved bladder or penile cancer. Sensitivity and specificity of fine needle aspiration samples were 70% and 100%, respectively. Blood tests obtained from patients with prostate cancer demonstrated high PSA mRNA values. CONCLUSIONS: The PSA mRNA RT-PCR ELISA method provides a sensitive photometric enzyme immunoassay for the detection of PSA mRNA, using nonradioactive techniques.

Enzyme-Linked Immunosorbent Assay↗
PubMed1999

Experimental determination of the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass.

This study investigated the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass in a canine model. The adequacy of cerebral oxygenation was determined from the adenosine concentration, the oxygen saturation of cerebral venous blood and brain oxyhemoglobin level. In experiment 1, nine beagles were cooled on bypass to a nasopharyngeal temperature of 18 degrees C and the perfusion flow rate was reduced in a stepwise fashion every 30 min from 100 to 50, 30, 20 and 10 ml/kg per min. In experiment 2, six beagles were cooled on bypass as in experiment 1, and flow was maintained at 30 ml/kg per min for 120 min. At a perfusion flow rate of 30 ml/kg per min, adequate cerebral oxygenation was maintained for 120 min. In contrast, perfusion flow rates of 20 and 10 ml/kg per min were associated with cerebral ischemia.

Adenosine Triphosphate↗
PubMed1999

Low-potassium University of Wisconsin solution for cardioplegia: improved protection of the isolated ischemic neonatal rabbit heart.

Recovery of cardiac function and high-energy phosphates following ischemia and reperfusion were determined for hearts perfused with low potassium University of Wisconsin solution, high potassium University of Wisconsin solution, St Thomas' solution, or subjected to hypothermia alone. Isolated hearts were arrested for either 3 h at 15 degrees C or 6 h at 20 degrees C (n = 7 for each group) with one of the four solutions and then reperfused. Aortic flow after ischemic arrest at 20 degrees C was 40.3 +/- 13.3%, 79.3 +/- 10.0%, 64.3 +/- 11.9% and 43.9 +/- 15.9% of control values for high potassium University of Wisconsin solution, low potassium University of Wisconsin solution, St Thomas' solution and hypothermia alone, respectively. Similar results were observed in hearts subjected to ischemic arrest at 15 degrees C. Myocardial adenosine triphosphate and creatine phosphate after reperfusion tended to be higher in the low potassium University of Wisconsin solution group. It is concluded that low potassium University of Wisconsin solution may provide reliable cardioplegia during surgery that requires prolonged cardiac arrest in neonates and infants.

Adenosine↗
PubMed1999

Augmented acetylcholine-induced, Rho-mediated Ca2+ sensitization of bronchial smooth muscle contraction in antigen-induced airway hyperresponsive rats.

Treatment with acetylcholine (ACh) of a beta-escin-permeabilized intrapulmonary bronchial smooth muscle of the rat induced force when the Ca2+ concentration was clamped at 1 microM. The ACh-induced Ca2+ sensitization of myofilaments was significantly greater in antigen-induced airway hyperresponsive rats than in control rats. The ACh-induced Ca2+ sensitization was completely blocked by treatment with Clostridium botulinum C3 exoenzyme, an inactivator of Rho family of proteins. Moreover, the protein level of RhoA in the intrapulmonary bronchi was significantly increased in the airway hyperresponsive rats. Thus, increased airway smooth muscle contractility observed in asthmatics may be related to augmented agonist-induced, Rho-mediated Ca2+ sensitization of myofilaments.

Acetylcholine↗
PubMed1999

Molecular cloning and functional expression of the human Golgi UDP-N-acetylglucosamine transporter.

We have cloned the human UDP-N-acetylglucosamine (UDP-GlcNAc) transporter cDNA, which was recognized through a homology search in the expressed sequence tags database (dbEST) based on its similarity to the human UDP-galactose transporter. The chromosomal location of the UDP-GlcNAc transporter gene was assigned to chromosome 1p21 by fluorescence in situ hybridization (FISH). The transporter was expressed ubiquitously in every tissue so far examined. Expression of the transporter cDNA in CHO-K1 cells in its native and in a C-terminally HA-tagged form indicated that the human UDP-GlcNAc transporter was localized in the Golgi apparatus. The membrane vesicles prepared from yeast cells expressing the cDNA product exhibited UDP-GlcNAc-specific transporting activity. Comparison among UDP-galactose, CMP-sialic acid, and UDP-GlcNAc transporters from several organisms enabled us to identify residues highly conserved among the transporters and residues specific for each group of transporters.

Amino Acid Sequence↗