Biomedical subjects

T Hayakawa

Publications and source records attributed to T Hayakawa.

At least 109 records · Page 6Linked to original sources

PubMed2001

Clinical results and development of variable-stiffness video colonoscopes.

BACKGROUND AND STUDY AIMS: This study was designed to assess the usefulness of variable-stiffness video colonoscopes, compared with conventional videoscopes. PATIENTS AND METHODS: The first prototype XCF-QAY1 and the latter prototype XCF-Q240A1 used in this study can be varied to 4 levels of stiffness of tube insertion during examination. In 352 consecutive colonoscopic examinations performed using these and two conventional scopes, the following data were recorded: time for intubation to the cecum, frequency of changes in the patients' posture, frequency of abdominal pressure attempts, and pain score. The degree of stiffness of the insertion tube and the examiners' impressions score were recorded only in procedures where the variable-stiffness scopes were used. RESULTS: There was no significant difference between colonoscopes in the pain score. Total colonoscopy rate was 97.4%. The frequency of usage of the varying stiffness control in the colon according to site was as follows: descending colon, 57.3%; transverse colon, 32.8%, sigmoid colon, 7.6%; and ascending colon, 2.3%. A significant difference in the mean time for intubation to the cecum between the XCF-Q240A1 and conventional scopes was observed. Moreover, there were significant differences in the frequency of abdominal pressure attempts and changes in the patient's posture between conventional scopes and the new scopes. CONCLUSIONS: These results suggest that only one scope, the XCF-Q240A1, is needed for any colonic examination by any examiner.

Aged↗

PubMed2001

Structural analysis of sulfated N-linked oligosaccharides in erythropoietin.

We previously demonstrated that high-performance liquid chromatography with electrospray ionization mass spectrometry (LC/MS) equipped with a graphitized carbon column (GCC) is useful for the structural analysis of carbohydrates in glycoproteins. Using LC/MS with GCC, sulfated N-linked oligosaccharides were found in erythropoietin (EPO) expressed in baby hamster kidney cells. Sulfation occurs in a part of the N-linked oligosaccharides in the EPO. Sulfated monosaccharide residue in the sulfated N-linked oligosaccharide was determined by exoglycosidase digestion followed by sugar mapping by LC/MS. The linkage position and branch-location of the sulfate group in the tetraantennary oligosaccharide were analyzed by (1)H-nuclear magnetic resonance. It was suggested that sulfation occurs on the C-6 position of GlcNAc located in the GlcNAcbeta1-4Manalpha1-3 branch.

Animals↗

PubMed2001

A Ca(2+)-dependent protein kinase that endows rice plants with cold- and salt-stress tolerance functions in vascular bundles.

A rice Ca(2+)-dependent protein kinase, OsCDPK7, is a positive regulator commonly involved in the tolerance to cold and salt/drought. We carried out in situ detection of the transcript and immunolocalization of the protein. In the wild-type rice plants under both stress conditions, OsCDPK7 was expressed predominantly in vascular tissues of crowns and roots, vascular bundles and central cylinder, respectively, where water stress occurs most severely. This enzyme was also expressed in the peripheral cylinder of crown vascular bundles and root sclerenchyma. Similar localization patterns with stronger signals were observed in stress-tolerant OsCDPK7 over-expressing transformants with the cauliflower mosaic virus 35S promoter. The transcript of a putative target gene of the OsCDPK7 signaling pathway, rab16A, was also detected essentially in the same tissues upon salt stress, suggesting that the OsCDPK7 pathway operates predominantly in these regions. We propose that the use of the 35S promoter fortuitously strengthened the localized expression of OsCDPK7, resulting in enhancement of the stress signaling in the inherently operating regions leading to improved stress tolerance.

Adaptation, Physiological↗

PubMed2001

Fatal bleeding from a residual vein at the esophageal ulcer base after successful endoscopic variceal ligation.

Endoscopic variceal band ligation (EVL) is now one of the accepted treatment options for esophageal varices, and the safety of this procedure has been proved. However, we experienced a patient who had a fatal massive bleeding after successful EVL for ruptured esophageal varix. Postmortem study revealed a residual vein at the base of the esophageal ulceration associated with the ligation, which was believed to be the site of the fatal bleeding. His platelet counts and prothrombin time were not very impaired. Our case indicates that fatal massive bleeding can occur in patients after successful EVL without specific risk factors and indicates the importance of the awareness of the possibility of these complications.

Esophageal and Gastric Varices↗

PubMed2001

Urinary excretion of trypsinogen activation peptide (TAP) in taurocholate-induced pancreatitis in rats.

Trypsinogen activation peptide (TAP) is a useful marker of severe acute pancreatitis. However, it is sometimes difficult to detect an elevation of plasma TAP in patients with acute pancreatitis because TAP is rapidly cleared from plasma. Therefore, urine TAP has been evaluated to provide an accurate prediction of the outcome of pancreatitis. In the present study, we examined the time course of plasma and urine TAP simultaneously after induction of taurocholate-induced pancreatitis in rats. Plasma TAP levels peaked at 1 hour after the induction of pancreatitis and then gradually decreased, but was still higher than prepancreatitis levels at 48 hours. Significant increases in urine TAP levels were seen at 0-6, 6-12, and 30-36 hours after induction of pancreatitis. The peak level of urine TAP output and TAP/creatinine ratio was observed at 6-12 and 30-36 hours, respectively. Urine TAP concentration showed a significant correlation with both urine TAP/creatinine ratio and TAP output in urine (p < 0.01). In conclusion, plasma TAP increased immediately after the induction of pancreatitis, but excretion of TAP into urine was delayed several hours in taurocholate-induced pancreatitis in rats. The measurement of urine TAP concentration alone sufficiently can reflect the amount of TAP liberated in the pancreas at initial stage of acute pancreatitis.

Acute Disease↗

PubMed2001

Elevation of serum cystatin C concentrations in patients with chronic liver disease.

OBJECTIVE: We examined serum cystatin C concentrations in patients to explore the possible clinical application of cystatin C as a marker of disease severity in cases of chronic liver diseases. METHODS: Serum cystatin C concentrations were determined by an enzyme-linked immunosorbent assay kit in 103 patients with various chronic liver diseases and compared with concentrations in healthy control volunteers. RESULTS: The mean cystatin C concentration was 0.68 +/- 0.03 mg/l in chronic hepatitis patients, 1.13 +/- 0.09 mg/l in liver cirrhosis patients and 1.16 +/- 0.10 mg/l in hepatocellular carcinoma patients, all significantly higher than concentrations in the control volunteers (P < 0.0001). Significant correlations were observed between cystatin C concentrations and total bilirubin levels, albumin levels, platelet levels, type IV collagen levels and hyaluronic acid levels. Serum cystatin C concentrations correlated well with histological stages despite the lack of correlation with histological grades. CONCLUSION: Our results show that serum cystatin C increases with the progression of chronic liver disease and that it is a potential marker for liver fibrosis.

Bilirubin↗

PubMed2001

Asymptomatic inflammatory bowel disease with special reference to ulcerative colitis in apparently healthy persons.

OBJECTIVE: We examined cases of asymptomatic inflammatory bowel diseases, particularly asymptomatic ulcerative colitis, which were found in apparently healthy Japanese persons who underwent general health screening. METHODS: Patients with positive immunological fecal occult blood test (IFOBT) among approximately 236,000 persons participating in the health screening program at the Aichi Prefectural Center for Health Care for the past 9 yr underwent total colonoscopy. In patients with ulcerative colitis, we investigated the sex and age distributions, extent of lesion, endoscopic activity, incidence rate, and clinical course. RESULTS: In all, 35 cases of inflammatory bowel disease were detected, and 274 cases of colorectal cancer (not discussed here) were detected in the same population. The 35 cases of inflammatory bowel disease consisted of 19 cases of ulcerative colitis (12 of asymptomatic and minimally symptomatic ulcerative colitis, and seven of symptomatic or with past history of ulcerative colitis); five of intestinal tuberculosis; two of Crohn's disease; two of amebic colitis; and seven of endoscopic colitis. The 12 patients with asymptomatic and minimally symptomatic ulcerative colitis consisted of 11 men and one woman aged 36-63 yr (mean 46.2 yr). We classified these cases into three grades of severity according to endoscopic findings: four cases were mild, eight moderate, and none severe. Of these 12 cases, three were found endoscopically because of positive IFOBT, although barium enema was normal. Anatomic types of colitis cases included three of total colitis, three left-sided colitis, two proctitis, and four right-sided or segmental colitis. In one case, the disease extended proximally during the course of observation. CONCLUSIONS: We found 35 cases of inflammatory bowel disease because of positive IFOBT performed as part of a general health screening. Of these, 19 cases were ulcerative colitis. These included many asymptomatic and minimally symptomatic cases, which could be very important in helping to elucidate the natural history of ulcerative colitis; thus, long-term follow up is necessary.

Adult↗

PubMed2001

Associations of alcohol drinking and nutrient intake with chronic pancreatitis: findings from a case-control study in Japan.

OBJECTIVE: The aim of this study was to examine the association of alcohol drinking and nutrient intake with chronic pancreatitis in a hospital-based case-control study. METHODS: From July, 1997, to December, 1998, 91 male patients, who were newly diagnosed as having chronic pancreatitis, were recruited as cases, and 175 controls were individually matched to each case for gender, age (+/-5 yr), hospital, and time of the first visit to a hospital (+/-1 yr). Information on demographic characteristics, smoking and drinking, and dietary habits were collected by a self-administered questionnaire. The strength of associations was examined by odds ratios (ORs) and 95% CIs calculated from conditional logistic regression models. RESULTS: Our study showed that the more the daily amount of alcohol drinking, the larger the OR. Men who consumed > or =100 g ethanol/day were at an approximately 11-fold increased risk as compared with nondrinkers. Long-term alcohol consumption (>35 yr) was associated with the increased risk (OR = 4.0). Risk of chronic pancreatitis remarkably increased with increasing cumulative alcohol consumption (trend p = 0.0001). Intakes of saturated fatty acid and vitamin E were negatively associated with the risk (trend p = 0.05 for saturated fatty acid and 0.03 for vitamin E). CONCLUSION: Our study clearly demonstrated that prolonged heavy alcohol consumption was an important and independent risk factor, and suggested a role of lower nutrient intakes in the development of chronic pancreatitis.

Adult↗

PubMed2001

Interferon responsiveness in patients infected with hepatitis C virus 1b differs depending on viral subtype.

BACKGROUND: Genotype 1b of hepatitis C virus (HCV) comprises mainly three subtypes, each named for its geographic prevalence (worldwide, W; Japan, J; and not in Japan, NJ). AIM: To characterise the newly identified subtypes of genotype 1b and to review factors associated with response to interferon (IFN) for each subtype. PATIENTS: Chronic hepatitis patients (80 men and 41 women; mean age 48.5 years, range 20.7--69.3) with HCV genotype 1b (W type, n=41; J type, n=38) or genotype 2a (n=42) were treated according to the same IFN protocol. Forty four patients (36.4%) negative for serum HCV RNA six months after cessation of treatment were considered complete responders. METHODS: Factors associated with complete response were investigated. RESULTS: Genotype 2a patients had lower viral loads (odds ratio 0.11 (95% confidence intervals (CI) 0.049--0.256)) and a better IFN response (odds ratio 0.25 (95% CI 0.117--0.552)) than genotype 1b patients whereas W type and J type patients had similar viral loads and responses to IFN. IFN response in W type patients was associated with female sex (odds ratio 0.23 (95% CI 0.055--0.983)) and low viral load (odds ratio 84.00 (95% CI 14.04--502.6)) whereas response in J type patients was related to transfusion history (odds ratio 7.20 (95% CI 1.443--35.91)), low viral load (odds ratio 117.0 (95% CI 17.82--768.3)), and genetic mutation in the interferon sensitivity determining region of the virus (odds ratio 0.08 (95% CI 0.013--0.553)). Multivariate analysis found low viral load (odds ratio 64.19 (95% CI 14.66--281.06)) to be the only significant independent factor associated with IFN response. CONCLUSIONS: Factors associated with IFN responsiveness in HCV infection differ with viral subtype.

Adult↗

PubMed2001

Role of cholecystokinin in the intestinal phase of pancreatic circulation in dogs.

The regulatory mechanisms of postprandial pancreatic hyperemia are not well characterized. The aim of this study is to clarify the role of cholecystokinin (CCK) in the intestinal phase of pancreatic circulation. Pancreatic, gastric, and intestinal blood flows were measured by ultrasound transit-time blood flowmeters in five conscious dogs. Pancreatic and gastric secretion and blood pressure were also monitored. Synthetic CCK octapeptide (CCK-8) or gastrin heptadecapeptide (gastrin-17) was infused intravenously, and milk was infused into the duodenum with or without loxiglumide, a specific CCK-A receptor antagonist. CCK-8 induced dose-related increases of pancreatic, but not gastric or intestinal, blood flow and protein secretion without affecting systemic blood pressure. Gastrin-17 did not affect pancreatic blood flow. An intraduodenal infusion of milk increased pancreatic and intestinal blood flows and pancreatic protein secretion. Loxiglumide completely inhibited pancreatic blood flow and protein responses to CCK-8 and milk but not the intestinal blood flow response. CCK is a potent and specific pancreatic vasodilator, with its effect mediated by CCK-A receptors. CCK plays an important role in the regulation of the intestinal phase of the pancreatic circulation in dogs.

Animals↗

PubMed2001

5-hydroxytryptamine strongly inhibits fluid secretion in guinea pig pancreatic duct cells.

We studied the distribution of 5-hydroxytryptamine- (5-HT-) containing cells in the guinea pig pancreas and examined the effects of 5-HT on fluid secretion by interlobular pancreatic ducts. The 5-HT-immunoreactive cells with morphological characteristics of enterochromaffin (EC) cells were scattered throughout the duct system and were enriched in islets of Langerhans. The fluid secretory rate in the isolated interlobular ducts was measured by videomicroscopy. Basolateral applications of 5-HT strongly but reversibly reduced HCO(3)-dependent, as well as secretin- and acetylcholine- (ACh-) stimulated, fluid secretion, whereas 5-HT applied into the lumen had no such effects. Secretin-stimulated fluid secretion could be inhibited by a 5-HT(3) receptor agonist, but not by agonists of the 5-HT(1), 5-HT(2), or 5-HT(4) receptors. Under the stimulation with secretin, 5-HT decreased the intracellular pH (pH(i)) and reduced the rate of pH(i) recovery after acid loading with NH(4)(+), suggesting that 5-HT inhibits the intracellular accumulation of HCO3(-). The elevation of intraductal pressure in vivo reduced secretin-stimulated fluid secretion, an effect that could be attenuated by a 5-HT(3) receptor antagonist. Thus, 5-HT, acting through basolateral 5-HT(3) receptors, strongly inhibits spontaneous, secretin-, and ACh-stimulated fluid secretion by guinea pig pancreatic ducts. 5-HT released from pancreatic ductal EC cells on elevation of the intraductal pressure may regulate fluid secretion of neighboring duct cells in a paracrine fashion.

Acetylcholine↗

PubMed2001

Preparation of and tissue response to DNA-lipid films.

DNA-containing films have the potential to form complexes with antibiotics or cytokines by intercalation or groove-binding. This principle can be highly relevant for regenerative wound-healing around oral implants and in periodontology. In this study, we prepared DNA-lipid films and examined tissue responses to them as an indicator of their biological properties. The lipids were synthesized from the reaction of L-alanine, n-alkyl alcohol, and p-toluenesulfonic acid. We prepared the self-standing, water-insoluble DNA-lipid films by casting the DNA-lipid complex from chloroform/ethanol solution. The DNA-lipid complexes, which had 1:1 ratios of phosphate anions to cationic lipid, were found to have a double-helical B-form structure. The DNA-lipid films were almost dissolved 3 days after subcutaneous implantation in the backs of rats. There were no inflammatory reactions or inhibition of new tissue formation. We concluded that DNA-lipid films can be prepared by simple methods, and that they do not cause an unfavorable tissue response.

Absorbable Implants↗

PubMed2001

Cellular localization of group IIA phospholipase A2 in rats.

It has been known that group II phospholipase A2 (PLA2) mRNA and protein are present in the homogenates of the spleen, lung, liver, and kidney in normal rats, but the cellular origin of this enzyme has not been yet identified. At present, five subtypes of group II PLA2 have been identified in mammals. Antibodies or mRNA probes previously used for detecting group II PLA2 need to be evaluated to identify the subtypes of group II PLA2. In this study we tried to identify group IIA PLA2-producing cells in normal rat tissues by in situ hybridization (ISH) using an almost full-length RNA probe for rat group IIA enzyme. Group IIA PLA2 mRNA was detected in megakaryocytes in the spleen and Paneth cells in the intestine by ISH. These cells were also immunopositive for an antibody raised against group IIA PLA(2) isolated from rat platelets. Group IIA PLA2 mRNA-positive cells were not detected in lung, liver, kidney, and pancreas. Under normal conditions, group IIA PLA2-producing cells are splenic megakaryocytes and intestinal Paneth cells in rats.

Animals↗

PubMed2001

Dai-kenchu-to enhances accelerated small intestinal movement.

The present study was conducted to clarify the effects of Dai-kenchu-to on accelerated small intestinal movement. We evaluated the effects of Dai-kenchu-to and its constituent herbs (dried ginger root, ginseng, zanthoxylum fruit, and malt sugar) on carbachol-accelerated mouse small intestinal transit, and contractions induced by low-frequency electrostimulation (ESC), KCl, or acetylcholine (ACh) using isolated guinea pig ileum. Dai-kenchu-to (10-300 mg/kg, p.o.) significantly improved carbachol-accelerated small intestinal transit in a dose-dependent manner. Using a concentration with the compounded rate for Dai-kenchu-to 300 mg/kg, carbachol-accelerated small intestinal transit was also significantly improved with a single dose of dried ginger root or ginseng. At a concentration of 3 x 10(-5) g/ml or less, Dai-kenchu-to, dried ginger root, and ginseng all inhibited ESC but not KCl- or ACh-induced contractions. However, at a higher concentration of Dai-kenchu-to (10(-4) g/ml) or zanthoxylum fruit (10(-5) g/ml or more) the ESC were enhanced. Both Dai-kenchu-to and dried ginger root at 10(-3) g/ml remarkably inhibited the KCl-induced contractions. These results indicate that Dai-kenchu-to improves accelerated small intestinal movement and that dried ginger root and ginseng may be involved in this effect. It is also thought that the mechanisms mainly involve the direct inhibition of smooth muscle but with a contribution from neural inhibition.

Acetylcholine↗

PubMed2001

Coronary heart disease mortality among men aged 35-44 years by prefecture in Japan in 1995-1999 compared with that among white men aged 35-44 by state in the United States in 1995-1998: vital statistics data in recent birth cohort.

The levels of risk factors for coronary heart disease (CHD) in men in the post World War II (WWII) birth cohort are almost similar between Japan and the USA, except for the considerably higher prevalence of cigarette smoking in Japan and the much higher prevalence of obesity in the USA. The present study evaluated the CHD mortality among men in the post WWII birth cohort by prefecture in Japan in 1995-1999 and then compared the data with those for white men in different states in the USA. There was a greater than 2-fold difference in CHD mortality among men aged 35-44 by prefecture in Japan: 5.3/100,000 in Kumamoto vs 12.6/100,000 in Tochigi. CHD mortality among men aged 35-44 in the top 3 prefectures in Japan is about half that of white men in the USA and is similar to that of white men in the lowest 3 states. The much lower CHD mortality in Japan does not appear to be caused by differences in the classification of causes of death and the results suggest that there may be strong and important protective factors that reduce the risk of CHD in Japan.

Adult↗

PubMed2001

Mechanism of atropine-resistant contraction induced by Dai-kenchu-to in guinea pig ileum.

To clarify the contractile mechanism of Dai-kenchu-to, the effects of hydroxy beta-sanshool (an ingredient of Zanthoxylum fruit), Zanthoxylum fruit (a constituent herb of Dai-kenchu-to) and Dai-kenchu-to were studied in mucosa-free longitudinal muscle of guinea pig ileum. Hydroxy beta-sanshool at 10(-7)-10(-5) g/ml induced dose-related contractions accompanied by autonomous contraction and produced an initial contraction at a concentration of 10(-4) g/ml or more. The contraction induced by hydroxy beta-sanshool (10(-5) g/ml) was significantly inhibited by tetrodotoxin or the capsaicin-receptor antagonist capsazepine. Although atropine or the substance P antagonist spantide tended to inhibit the contraction, a combination of atropine and spantide almost abolished the contraction by hydroxy beta-sanshool. The P2-purinoceptor antagonist pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid did not affect hydroxy beta-sanshool-induced contraction in the presence or absence of spantide. The tonic contractions by Zanthoxylum fruit (2 x 10(-4) g/ml) and Dai-kenchu-to (10(-3) g/ml) were significantly inhibited or tended to be inhibited by atropine, spantide, tetrodotoxin or capsazepine and were remarkably suppressed by the combination of atropine and spantide. These results suggested that acetylcholine release from intrinsic cholinergic nerves and tachykinins from sensory neurons are involved in the contractions induced by hydroxy beta-sanshool and that tachykinins may be involved in the atropine-resistant contraction by Dai-kenchu-to.

Animals↗

PubMed2001

Induction and secretion of RNA-degrading enzymes by phosphate deficiency in Pholiota nameko.

Changes in activity of RNA-degrading enzyme and amounts of phosphorus in mycelia and culture filtrate during Pi-sufficient and -deficient cultures of Pholiota nameko were investigated. The results showed that the intracellular and extracellular activities are controlled by the Pi concentration in the medium. Moreover, the induction and secretion of RNA-degrading enzymes under the Pi-deficient condition were analyzed by activity staining.

Acid Phosphatase↗

PubMed2001

Impaired nitric oxide production and enhanced autoregulation of coronary circulation in young spontaneously hypertensive rats at prehypertensive stage.

In the current study, we investigated the NO-generation pathway in response to mechanical stimuli in SHR at the prehypertensive stage. To examine the role of NO in coronary autoregulation, we evaluated the effects of L-NAME on the coronary flow in SHR at both the prehypertensive and hypertensive stages. Isolated perfused hearts from 5- and 15-week-old SHR and from age-matched Wistar-Kyoto rats (WKY) were used. After stabilization at 60 mmHg, perfusion pressure was immediately raised to 90 mmHg to record the change in coronary flow for 10 min without (control) or with NO synthesis blockade by Nomega-nitro-L-arginine methyl ester (L-NAME). NOx- (nitrite/nitrate) was measured in coronary effluent. At 5 weeks of age, SHR did not have hypertension, while the coronary autoregulation was enhanced. L-NAME did not affect this enhanced autoregulation in 5-week-old SHR. At perfusion pressures of both 60 and 90 mmHg, 5-week-old SHR showed less coronary NOx- production than age-matched WKY. At 15 weeks, SHR showed a higher blood pressure than WKY. The coronary autoregulation in SHR remained higher than that in WKY, but was below that in 5-week-old SHR. NOx- production in 15-week-old SHR recovered to the level of age-matched WKY. These results indicate that NOx- production induced by mechanical stimulation was markedly reduced in 5-week-old SHR at the prehypertensive stage, which may have enhanced coronary autoregulation. An impaired nitric oxide production may precede the onset of hypertension in SHR.

Animals↗