Biomedical subjects

T Tsuda

Publications and source records attributed to T Tsuda.

At least 127 records · Page 7Linked to original sources

PubMed1999

MUC1 mucin mRNA expression in stage I lung adenocarcinoma and its association with early recurrence.

BACKGROUND: MUC1 is a membrane-bound mucin with an extensively O-glycosylated core protein and is developmentally regulated and aberrantly expressed by carcinomas. A high level of MUC1 mucin expression and secretion is associated with high metastatic potential and a poor prognosis. We studied the expression of MUC1 messenger ribonucleic acid (mRNA) in stage I lung adenocarcinoma by reverse transcriptase-polymerase chain reaction and examined its correlation with early recurrence. METHODS: The expression of MUC1 mRNA, in surgical specimens from 33 patients with stage I lung adenocarcinoma was determined by reverse transcriptase-polymerase chain reaction. The MUC1 and beta-actin sequences were subsequently coamplified to analyze the semiquantitative determination by polymerase chain reaction. The ratio of MUC1 to beta-actin product was used for further analysis. RESULTS: An analysis of the disease-free survival (median follow-up, 33.4 months) revealed that a high expression of MUC1 was associated with early recurrence (p = 0.0191). Six of the 33 patients had recurrence within 2 years after operation. The recurrence sites suggested hematogenic metastasis. CONCLUSIONS: Our results indicate that MUC1 mRNA level may be useful as a marker of early recurrence in stage I lung adenocarcinoma.

Adenocarcinoma↗

PubMed1999

Prevention of postoperative air leakage from lungs using a purified human collagen membrane-polyglycolic acid sheet.

BACKGROUND: Human amnion has useful biomedical applications because it contains a large amount of human collagen fibers. We prepared purified human collagen membrane (HCM) from human amnion and used it to develop a new sheet by combining it with synthetic bioabsorbable polyglycolic acid (PGA) mesh. We evaluated its efficacy in preventing air leakage from the lungs of dogs. METHODS: In 20 dogs, HCM-PGA sheet (n = 5), sheets using fibrin glue with a separate application method (n = 5), a mixed application method (n = 5), and fibrin glue alone (n = 5), were used as dressing materials after partial lung resection. RESULTS: The HCM-PGA sheet using fibrin glue with a separate application method was shown to be significantly more effective by an air leakage pressure test than the other three methods. These results indicate that the HCM-PGA sheet is useful for preventing air leakage from the lung. CONCLUSIONS: The HCM-PGA sheet is more effective than conventional fibrin glue for controlling postoperative air leakage.

Amnion↗

PubMed1999

Inhibition of eosinophil activation in bronchoalveolar lavage fluid from atopic asthmatics by Y-24180, an antagonist to platelet-activating factor.

We examined the effects of Y-24180, a potent and long-acting antagonist to platelet-activating factor (PAF) receptor, on the expression of adhesion molecules in peripheral blood and bronchoalveolar lavage fluid (BALF) eosinophils from atopic asthmatics. Y-24180 (20 mg/day) was administered to 4 atopic asthmatics for 8 weeks. The number of eosinophils, the level of eosinophil cationic protein (ECP), the bindings of soluble intercellular adhesion molecule-1 (sICAM-1) and fibronectin (FN), and the expressions of CD11b (alpha chain of Mac-1) and CD49d (alpha chain of VLA-4) on eosinophils were evaluated in peripheral blood (n=4) and BALF (n=3) before and after the administration of Y-24180. The infiltration of eosinophils into the bronchial wall was also examined by taking biopsies. Eosinophil count, sICAM-1 and FN binding to eosinophils in BALF significantly decreased after the administration of Y-24180 (p<0.05). The level of CD11b expression also decreased remarkably after the administration (n=2). In peripheral blood, eosinophil count and ECP level did not change. The binding of sICAM-1 and FN, and expression of CD11b on eosinophils in peripheral blood showed a tendency to decrease after the administration. The level of CD49d expression on eosinophils changed neither in BALF nor in blood. Eosinophil infiltration into the bronchial wall markedly decreased in one out of 3 cases after the administration. These results suggest that Y-24180 inhibits the activation of eosinophils by antagonizing the actions of PAF in atopic asthmatics.

Adult↗

PubMed1999

Induction of blood-brain barrier properties in immortalized bovine brain endothelial cells by astrocytic factors.

The blood-brain barrier (B-BB) protects the free passage of substances into the brain and maintains the homeostasis of the central nervous system. It is commonly accepted that astrocytes surrounding brain endothelial cells influence the B-BB formation and the exhibition of B-BB function of capillaries. To begin the in vitro study on the B-BB, it is essential to obtain a homogenous and sufficient supply of brain endothelial cells as well as astrocytes. We thus immortalized the bovine brain endothelial cell (BBEC) by transfection of the SV40 large T antigen and obtained a single clone, t-BBEC-117, which retained the brain endothelial cell phenotype. Astrocyte in co-culture was found to tighten the intercellular contacts of the immortal cells resulting in a reduced L-glucose permeability, and its conditioned medium (CM) augmented a B-BB phenotype, alkaline phosphatase (ALP) activity. Among known astrocytic factors, only fibroblast growth factor-basic (bFGF) could mimic the actions of astrocytes as measured by L-glucose permeability and ALP activity. Moreover, anti-bFGF antibody canceled 90% of ALP activation by astrocyte CM. Basic FGF, however, failed to induce other B-BB phenotypes such as the expressions of multidrug resistance (mdr) and glucose transporter (GLUT-1) genes. These data suggest that bFGF is one of the most plausible astrocytic factors to induce the B-BB properties of immortal brain endothelial cells together with some unknown factors in the astrocyte CM.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

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

Presenilin-1 mutations downregulate the signalling pathway of the unfolded-protein response.

Missense mutations in the human presenilin-1 (PS1) gene, which is found on chromosome 14, cause early-onset familial Alzheimer's disease (FAD). FAD-linked PS1 variants alter proteolytic processing of the amyloid precursor protein and cause an increase in vulnerability to apoptosis induced by various cell stresses. However, the mechanisms responsible for these phenomena are not clear. Here we report that mutations in PS1 affect the unfolded-protein response (UPR), which responds to the increased amount of unfolded proteins that accumulate in the endoplasmic reticulum (ER) under conditions that cause ER stress. PS1 mutations also lead to decreased expression of GRP78/Bip, a molecular chaperone, present in the ER, that can enable protein folding. Interestingly, GRP78 levels are reduced in the brains of Alzheimer's disease patients. The downregulation of UPR signalling by PS1 mutations is caused by disturbed function of IRE1, which is the proximal sensor of conditions in the ER lumen. Overexpression of GRP78 in neuroblastoma cells bearing PS1 mutants almost completely restores resistance to ER stress to the level of cells expressing wild-type PS1. These results show that mutations in PS1 may increase vulnerability to ER stress by altering the UPR signalling pathway.

Alzheimer Disease↗

PubMed1999

Nitrile hydratase involved in aldoxime metabolism from Rhodococcus sp. strain YH3-3 purification and characterization.

Nitrile hydratase responsible for aldoxime metabolism from the E-pyridine-3-aldoxime degrading bacterium, Rhodococcus sp. strain YH3-3 was purified and characterized. Addition of cobalt ion was necessary for the formation of enzyme. The enzyme activity was highly induced not only by nitriles and amides but also by several aldoxime compounds. The enzyme was purified approximately 108-fold with a 16% yield from the cell-free extract of the strain. The native enzyme had a Mr of approximately 130 000 and consisted of two subunits (alpha-subunit, 27 100; beta-subunit, 34 500). The enzyme contained approximately 2 mol cobalt per mol enzyme; it showed a maximum activity at 60 degrees C and at 40 degrees C under the rate assay and end-point assay conditions, respectively, and was stable over a wide range of pH (pH 2.5-11.0). The enzyme had a wide substrate specificity: it acted on aliphatic saturated and unsaturated as well as aromatic nitriles. The N-terminus of the beta-subunit showed good sequence similarities with those of other nitrile hydratases. Nitrile hydratase is part of the metabolic pathway for aldoximes in microorganisms.

Amino Acid Sequence↗

PubMed1999

Interleukin-4-producing cells in idiopathic pulmonary fibrosis: an immunohistochemical study.

OBJECTIVE: Interleukin-4 stimulates collagen synthesis in fibroblasts in vitro. The purpose of this study was to clarify the role of interleukin-4 in the pathogenesis of idiopathic pulmonary fibrosis. METHODOLOGY: We compared interleukin-4 expressing cells in tissues from 11 patients with pathologically confirmed idiopathic pulmonary fibrosis with early stage inflammatory lesions versus advanced lesions. We also performed double staining in order to elucidate which inflammatory cells produce interleukin-4 in idiopathic pulmonary fibrosis. RESULTS: Greater numbers of interleukin-4 positive cells were observed in the advanced lesions than in the early lesions. We also found that early stage lesions showed a predominance of CD3/interleukin-4 double positive cells whereas, the advanced stage lesions had higher percentages of the EG2/interleukin-4 double positive cells and the tryptase/interleukin-4 double positive cells. CONCLUSIONS: Our results suggest that interleukin-4 may be involved in progression of interstitial fibrosis in idiopathic pulmonary fibrosis, in which we confirmed a significant contribution of eosinophils and mast cells to interleukin-4 production.

Adult↗

PubMed1999

Cloning and expression of a human gene encoding an N-acetylgalactosamine-alpha2,6-sialyltransferase (ST6GalNAc I): a candidate for synthesis of cancer-associated sialyl-Tn antigens.

The sialyl-Tn (sTn) antigen is a well known cancer-associated antigen, the expression of which is related to the prognosis of cancer patients. We aimed to isolate a human gene encoding an N -acetylgalactosamine alpha2,6-sialyltransferase which synthesizes sTn antigen, and to characterize the enzyme. Degenerate primers encoding sialyl motifs were used for the polymerase chain reaction to amplify complementary DNAs prepared from RNAs of human pyloric mucosae with intestinal metaplasia, which abundantly expressed sTn antigen, followed by screening of full-length cDNAs using the amplified DNA fragment as a probe. We isolated two human cDNA clones, long-form (2.46 kb) and short-form (2.23 kb) cDNAs. The former encodes an active enzyme with a predicted 600 amino acid sequence. The latter, a splice-variant of the long-form, encodes an inactive enzyme. HCT15 human colorectal cancer cells stably expressing the long-form cDNA expressed sTn epitopes on O -glycans. The long form cDNA was considered to encode a human homologue of chick ST6GalNAc I for the following reasons: (1) the putative amino acid sequence showed greater homology to that of chick ST6GalNAc I (55%) compared to other sialyltransferases, (2) it encodes the extraordinarily long stem region that is a typical feature of chick ST6GalNAc I, and (3) the substrate specificity was very similar to that of chick ST6GalNAc I. In situ hybridization demonstrated that the localization of transcripts correlated well with that of sTn antigen in gastric cancer cells and Goblet cells in intestinal metaplastic glands. Thus, we determined that the long-form cDNA of the human ST6GalNAc I gene encodes the probable candidate for the human sTn synthase(s).

Acetylglucosamine↗

PubMed1999

Effect of temporary hepatic venous occlusion on hepatic arterial embolization. An experimental study.

RATIONALE AND OBJECTIVES: The authors evaluated the effect of hepatic venous occlusion on hepatic arterial embolization in rats. METHODS: A Lipiodol-Iopamidol mixture was injected into the proper hepatic artery in rats during clamping the right side of the hepatic venous confluence. The distribution of Lipiodol-Iopamidol mixture in the sinusoids was analyzed by histological examination with en bloc silver impregnation. The extent of the distribution of Lipiodol-Iopamidol mixture was compared in sinusoids with hepatic venous occlusion and in sinusoids without hepatic venous occlusion. RESULTS: Lipiodol-Iopamidol mixture was more widely distributed in the lobules with hepatic venous occlusion than in the lobules without occlusion. CONCLUSIONS: Hepatic venous occlusion may enhance the effect of hepatic arterial embolization using Lipiodol emulsions and could be useful in the treatment of hepatocellular carcinoma.

Animals↗

PubMed1999

Hepatic extraction fraction of hepatobiliary radiopharmaceuticals measured using spectral analysis.

Measuring the hepatic extraction fraction (HEF) of a hepatobiliary radiopharmaceutical helps to differentiate hepatocyte from biliary tract diseases, and it is generally performed using deconvolution analysis. In this study, we measured HEF using spectral analysis. With spectral analysis, HEF was calculated from (the sum of the spectral data obtained by spectral analysis--the highest frequency component of the spectrum) divided by (the sum of the spectral data) x 100 (%). We applied this method to dynamic liver scintigraphic data obtained from six healthy volunteers and from 46 patients with various liver diseases, using 99Tcm-N-pyridoxyl-5-methyltryptophan (PMT). We also measured HEF using deconvolution analysis, in which the modified Fourier transform technique was employed. The HEF values obtained by spectral analysis correlated closely with those obtained by deconvolution analysis (r = 0.925), suggesting our method is valid. The HEF values obtained by spectral analysis decreased as the severity of liver disease progressed. The values were 100.0 +/- 0.0%, 94.7 +/- 13.6%, 76.2 +/- 27.4%, 45.7 +/- 15.6%, 82.7 +/- 24.2% and 95.2 +/- 11.8% (mean +/- S.D.) for the normal controls (n = 6), mild liver cirrhosis (n = 16), moderate liver cirrhosis (n = 11), severe liver cirrhosis (n = 5), acute hepatitis (n = 8) and chronic hepatitis groups (n = 6), respectively. The HEF was obtained more simply and rapidly by spectral analysis than by deconvolution analysis. The results suggest that our method using spectral analysis can be used as an alternative to the conventional procedure using deconvolution analysis for measuring HEF.

Aged↗

PubMed1999

Increased 8-hydroxyguanine in DNA and its repair activity in hamster and rat lung after intratracheal instillation of crocidolite asbestos.

Asbestos and man-made-mineral fibers are known to increase one type of oxidative DNA damage, 8-hydroxyguanine (8-OH-(Gua), in vitro. In this study, we analyzed the 8-OH-Gua level in DNA and its repair activity after a single intratracheal instillation of fibers (crocidolite or glass) or saline to Syrian hamsters or Wistar rats. The 8-OH-Gua level was measured with a high-performance liquid chromatography-electrochemical detector (HPLC-ECD) system. The 8-OH-Gua repair enzyme activity was determined with an endonuclease nicking assay using a 32P-labeled or fluorescently labeled 22mer DNA that contains 8-OH-Gua at a specific position. A significant increase in the 8-OH-Gua level in the lung DNA was observed 1 day after the exposure to crocidolite, as compared to the saline control. The repair activity was increased significantly at 7 days. On the other hand, after exposure to glass fibers, little or no increase of these carcinogenicity indicators was detected. These assays of 8-OH-Gua and its repair activity in short-term animal experiments will be useful for evaluating the carcinogenicity of fibers. This is the first report of the increase of 8-OH-Gua and its repair activity in the animal lung after the instillation of asbestos fibers.

Animals↗

PubMed1999

Identification and PCR-restriction fragment length polymorphism analysis of a variant of the Ibaraki virus from naturally infected cattle and aborted fetuses in Japan.

One hundred fourteen field isolates of the Ibaraki virus (IBAV), a member of the epizootic hemorrhagic disease virus serotype 2 (EHDV-2), were isolated from blood samples of affected and apparently healthy cattle and Culicoides biting midges and from blood samples of dams and internal organs of aborted fetuses during an outbreak of Ibaraki disease in the southern part of Japan in 1997. In this outbreak, 242 cattle showed typical symptoms of the disease, and several hundred dams had miscarriages or stillbirths. The viruses that induced typical Ibaraki disease and reproductive problems among cattle were identical and were antigenically closely related to but distinct from previous isolates of IBAV and EHDV-2. The virus was considered to be a putative agent of this outbreak. Reverse transcription-PCR based on segment 3 of the RNA genome of EHDV-2 and restriction fragment length polymorphism analysis of the PCR products were conducted to compare the genomes of the viruses. The results suggested that the virus isolated in 1997 was a variant of IBAV and might be exotic.

Abortion, Veterinary↗

PubMed1999

Perceived job stress and mental health in precision machine workers of Japan: a 2 year cohort study.

OBJECTIVES: To determine whether perceived job stress affects mental health in occupational settings. METHODS: A 2 year cohort study was conducted. Initially, a survey including the general health questionnaire (GHQ) and a questionnaire about perceived job stress was carried out. Of 462 workers who initially showed a GHQ score of < or = 7,310 were successfully followed up for 2 years. The 2 year risks of developing mental ill health (a GHQ score > or = 8) were assessed relative to perceived job stress. To control for potential confounding factors, multiple logistic regression analyses were conducted. RESULTS: The overall 2 year risk for developing mental ill health was high at 57.7%. Workers who reported aspects of perceived job stress showed a greater 2 year risk than those without stress. Multiple logistic regression analyses showed that some components of perceived job stress were associated with a higher 2 year risk, among which "not allowed to make mistakes" showed the largest adjusted odds ratio (OR) (95% confidence interval (95% CI) of 2.37 (1.32 to 4.29). "Poor relationship with superior" had a significant effect on mental health only in women, with an adjusted OR (95% CI) of 3.79 (1.65 to 8.73). CONCLUSIONS: Certain specific items of perceived job stress seem to be associated with mental ill health in workers. These could broadly be described as job strain, or job demand items. The type of job stress that predicts mental health may be dependent on the characteristics of the workplace investigated.

Adult↗

PubMed1999

Combined effect of cigarette smoke and mineral fibers on the gene expression of cytokine mRNA.

To investigate which parameters are stimulated by mineral fibers and whether cigarette smoke enhanced a fiber-induced response, we examined the level of cytokine mRNA from alveolar macrophages (AMs) and lungs of rats exposed to mineral fibers and cigarette smoke in vivo. Male Wistar rats were given a single intratracheal instillation of 2 mg of Union Internationale Contre le Cancer chrysotile or refractory ceramic fiber (RF1). The animals then inhaled a side stream of smoke 5 days per week for 4 weeks. The expression of manganese superoxide dismutase, inducible nitric oxide synthase (iNOS), basic fibroblast growth factor (bFGF), interleukin-1[alpha] (IL-1[alpha]), interleukin-6 (IL-6), and tumor necrosis factor-[alpha] (TNF[alpha]) mRNA from lipopolysaccharide-stimulated AMs and lungs of rats exposed to mineral fibers and/or cigarette smoke were assessed using semiquantitative reverse-transcriptase polymerase chain reaction. Exposure only to cigarette smoke increased in IL-1[alpha] mRNA levels in AMs. Chrysotile stimulated the expression of IL-1[alpha], TNF[alpha], and IL-6 in AMs, and the expression of bFGF in lungs. RF1 resulted in increased expression of IL-1[alpha] and TNF[alpha] in AMs. Cigarette smoke stimulated the gene expression of iNOS in AMs and IL-6 and bFGF in lungs treated with chrysotile; IL-1[alpha] in AMs and bFGF in lungs did the same in lungs with RF1. Among these cytokines, message levels of IL-1[alpha], iNOS, and bFGF were increased in rats stimulated with mineral fibers, and the stimulating effects of mineral fibers were enhanced by cigarette smoke. Therefore, IL-1[alpha], iNOS, and bFGF would be the possible parameters of the lung remodeling induced by mineral fibers.

Animals↗

PubMed1999

Craniofacial skeletal abnormalities in anomalous calves with clefts of the face.

Thirteen anomalous calves with clefts of the face were morphologically examined, and craniofacial skeletons were studied in detail. According to the type and site of the cleft, four groups could be distinguished: median cleft lip and jaw (CLJ); median cleft lip, jaw, and palate (CLJP); lateral CLJ; and cleft palate (CP), including unilateral and bilateral type. Craniofacial skeletal abnormalities were observed in several bones at the roof, wall, and floor of the nasal cavity and at the boundary portion between the nasal and cranial cavities. Fissure formation at the cranial sutures, partial absence of the nasal process of the incisive bone, and opening of the bony palate were characteristic changes in median CLJ and CLJP, lateral CLJ, and CP, respectively. Furthermore, various associated changes were recognized in the median and paramedian skeletal elements of the face and other organs. The morphological changes of craniofacial skeletons with various types of clefts of the face depended on the site and degree of the cleft formation and reflected developmental errors of the facial embryonic segments. These changes would suggest disorders of the correlated development of facial processes and of other fetal organs of the face. For these conditions, etiologically hereditary cases were negative.

Animals↗

PubMed1999

Therapeutic efficacy of transcranial magnetic stimulation for hereditary spinocerebellar degeneration.

We applied transcranial magnetic stimulation (TMS) as a therapeutic approach for patients with spinocerebellar degeneration (SCD). The subjects were four familial SCD patients (three men and one woman) aged from 27 to 76 years old. They were genetically analysed as two spinocerebellar ataxia type 6 (SCA 6), one SCA 1, and one SCA 7. The durations of their illness ranged from 1 to 7 years. Ten consecutive magnetic pulses were delivered over the scalp corresponding to the right cerebellar hemisphere, the middle of the cerebellum and the left cerebellar hemisphere, respectively, every day for 21 days. In all patients, the time and the number of steps required for a 10 m walk examination were significantly decreased after TMS trial compared with those before TMS. The number of feasible steps in tandem gait test increased. The total length of tracing body balance for 30 seconds measured by gravinometer was significantly decreased. However, nystagmus, dysarthria or incoordination of the upper limbs did not change after TMS trial. It is of interest that the blood flow of the cerebellar hemisphere, putamen and pons were significantly increased during the TMS trial. Although we do not know the exact mechanism by which TMS improved the ataxic gait, we speculate the increase of blood flow in the cerebellum, putamen and pons takes part in the improvement. These findings suggest that TMS over the cerebellum may be an effective therapy for patients with SCD.

Adult↗

PubMed1999

The role of perceived job stress in the relationship between smoking and the development of peptic ulcers.

Although smoking has been considered a risk factor in causing pepticulcers, no study has examined the effects of job stress on the relationship between peptic ulcers and smoking. To establish a link between gastric or duodenal ulcers over two years and a state of perceived job stress, a questionnaire, including questions on demographics, smoking, history of peptic ulcer and perceived job stress was conducted. Follow-up surveys were carried out every six months to accumulate the data for this analysis and the time span of this follow up study was two years. To examine the role of perceived job stress on the relationship between smoking and peptic ulcers, stratified analyses were performed. Some specific causes of perceived job stress such as "Too much competition," "Schedule is too tight or pressed to work too hard" had high estimated relative risks: 2.13 with 95% confidence interval (CI) of 1.09-4.16 and 2.50 with 95% CI of 0.98-6.40, respectively. Stratified analyses suggested an effect-measure modification of perceived job stress in the relationship between peptic ulcers and smoking. Multiplicative and additive models suggest positive interaction between perceived job stress and smoking. These results suggest that specific perceived job stress is an effect modifier in the relationship between the history of the peptic ulcer and smoking.

Adult↗