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Biomedical subjects

T Hirayama

Publications and source records attributed to T Hirayama.

At least 37 records · Page 2Linked to original sources
PubMed2001

Helicobacter pylori-mediated transcriptional regulation of the human beta-defensin 2 gene requires NF-kappaB.

Human beta-defensin 2 (hBD-2) is an antimicrobial peptide involved in host defence against bacterial infection in epithelial tissues. Its levels are dramatically increased after bacterial infection. The involvement of NF-kappaB in Helicobacter pylori-mediated induction of hBD-2 promoter activity was examined. A luciferase reporter plasmid containing the hBD-2 promoter extending from -2110 base pairs to -1 was transiently expressed in MKN45 cells, and promoter activity was determined after incubation with H. pylori for 6 h. Deletion or mutation of the NF-kappaB site at -208 abolished activation of the hBD-2 promoter. Only H. pylori strains carrying a cag pathogenicity island (PAI) induced activation of the NF-kappaB site of the hBD-2 promoter gene. By gel retardation analyses, H. pylori increased NF-kappaB binding to hBD-2 promoter gene sequences. Supershift analysis demonstrated that whereas H. pylori activated NF-kappaB p65-p65 and p50-p50 homodimers, and the p65-p50 heterodimer of NF-kappaB, only the p65-p65 homodimer bound to the NF-kappaB site of the hBD-2 promoter. Thus, specific NF-kappaB proteins are important cis-elements for induction of hBD-2 gene transcription by H. pylori.

Cell Line↗
PubMed2001

Examination of electrostatic potential distribution across an implanted p-n junction by electron holography.

In the manufacture of semiconductor microelectronic devices, a p-n junction is formed usually by implanting a high concentration of impurity into a less heavily doped region and then heat annealing. A Si/Si p-n junction test sample has been made following the above practical process and thinned for electron holographic observation by using argon ion-milling. From the reconstructed phase image, the phase shift induced by potential drop across p-n junction can be seen clearly. To characterize quantitatively this potential drop, the mean inner potential V0 of silicon was measured precisely by electron holographic method. By measuring 25 different crystalline silicon spheres with diameter ranging from 40 to 170 nm, an average result of V0 = 12.16 +/- 0.83 V was obtained. By using this V0 value, a quantitative measurement yields the potential drop approximately 0.70 V, which is reasonably consistent with expected Si/Si junction parameter. The thickness of electric dead layer in depletion region produced from this measuring is approximately 20 nm on each sample surface.

Journal Article↗
PubMed2001

Hyperosmotic stress induces a rapid and transient increase in inositol 1,4,5-trisphosphate independent of abscisic acid in Arabidopsis cell culture.

Phospholipid metabolism is involved in hyperosmotic-stress responses in plants. To investigate the role of phosphoinositide-specific phospholipase C (PI-PLC)-a key enzyme in phosphoinositide turnover-in hyperosmotic-stress signaling, we analyzed changes in inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) content in response to hyperosmotic shock or salinity in Arabidopsis thaliana T87 cultured cells. Within a few s, a hyperosmotic shock, caused by mannitol, NaCl, or dehydration, induced a rapid and transient increase in Ins(1,4,5)P3. However, no transient increase was detected in cells treated with ABA. Neomycin and U73122, inhibitors of PI-PLC, inhibited the increase in Ins(1,4,5)P3 caused by the hyperosmotic shock. A rapid increase in phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) in response to the hyperosmotic shock also occurred, but the rate of increase was much slower than that of Ins(1,4,5)P3. These findings indicate that the transient Ins(1,4,5)P3 production was due to the activation of PI-PLC in response to hyperosmotic stress. PI-PLC inhibitors also inhibited hyperosmotic stress-responsive expression of some dehydration-inducible genes, such as rd29A (lti78/cor78) and rd17 (cor47), that are controlled by the DRE/CRT cis-acting element but did not inhibit hyperosmotic stress-responsive expression of ABA-inducible genes, such as rd20. Taken together, these results suggest the involvement of PI-PLC and Ins(1,4,5)P3 in an ABA-independent hyperosmotic-stress signal transduction pathway in higher plants.

Abscisic Acid↗
PubMed2001

Induction of monocyte chemoattractant protein 1 by Helicobacter pylori involves NF-kappaB.

Helicobacter pylori stimulates secretion of monocyte chemoattractant protein 1 (MCP-1) from gastric epithelial cells. Secretion of this chemokine may be instrumental in monocyte infiltration of the gastric epithelium that characterizes H. pylori gastritis. The aim of this study was to identify the mechanism by which H. pylori induces MCP-1 production. Induction of MCP-1 mRNA was assessed by reverse transcription-PCR. We used luciferase reporter assays to monitor activation of the MCP-1 gene promoter and electrophoretic mobility shift assays to explore binding of transcription factors to this promoter. H. pylori infection increased MCP-1 mRNA expression from gastric epithelial cells. Induction of MCP-1 mRNA relies on an intact cag pathogenicity island. We identified two closely spaced NF-kappaB-binding sites within the MCP-1 distal enhancer as required for H. pylori-induced MCP-1 gene transcription. H. pylori infection led to the specific activation of NF-kappaB complexes containing p50 and p65. Kinase-deficient mutants of NF-kappaB-inducing kinase (NIK) and IkappaB kinases (IKK) caused suppression of MCP-1 distal enhancer-dependent reporter activity following H. pylori infection. H. pylori infection induces the activation of NF-kappaB via the NIK-IKK signaling complex, leading to MCP-1 gene transcription in gastric epithelial cells.

Chemokine CCL2↗
PubMed2001

Expression of human beta-defensin 2 (hBD-2) in Helicobacter pylori induced gastritis: antibacterial effect of hBD-2 against Helicobacter pylori.

BACKGROUND: Human beta-defensin 2 (hBD-2) plays a role in the innate defence system at mucosal surfaces. Colonisation of Helicobacter pylori in the stomach is an important pathological factor in gastrointestinal illnesses, including gastritis, peptic ulcer, and gastric adenocarcinoma. AIMS: To evaluate the antibacterial role of hBD-2 against H pylori infection in the gastric mucosa. SUBJECTS: Biopsied gastric mucosa specimens from H pylori positive (n=6) and H pylori negative (n=6) individuals were used. H pylori was determined by the presence of urease activity and microscopic examination. METHODS: The specimens were examined for hBD-2 expression by reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, and in situ hybridisation. The antibacterial effect of hBD-2 against H pylori was evaluated by the number of colony forming units of H pylori after incubation with 0, 10(-9), 10(-8), 10(-7), 10(-6), or 10(-5) M of hBD-2 peptide. RESULTS: All six H pylori positive specimens expressed a high level of hBD-2 mRNA while hBD-2 mRNA was not detected in the H pylori negative specimens by RT-PCR. Immunohistochemistry using anti-hBD-2 antiserum revealed that hBD-2 was expressed in the surface epithelium of H pylori infected specimens. In gastric specimens obtained after H pylori eradication, hBD-2 immunoreactivity had dramatically decreased. In situ hybridisation confirmed that hBD-2 transcripts were localised in the epithelium of H pylori infected gastric specimens. Incubation with hBD-2 reduced the growth rate of cultured H pylori in a dose dependent manner, and incubation with 10(-5) M hBD-2 completely inhibited the proliferation of H pylori. CONCLUSIONS: H pylori infection induces hBD-2 expression in the human gastric epithelium. hBD-2 inhibited the growth of H pylori in vitro, suggesting that hBD-2 plays an antibacterial role in H pylori induced gastritis.

Aged↗
PubMed2001

Dynamin is involved in human epithelial cell vacuolation caused by the Helicobacter pylori-produced cytotoxin VacA.

The Helicobacter pylori-produced cytotoxin VacA induces intracellular vacuolation. To elucidate the molecular mechanism of vacuole formation by VacA, we examined the participation of dynamin, a GTPase functioning in intracellular vesicle formation, in human HeLa cells. Immunocytochemistry revealed that endogenous dynamin was localized to vacuoles induced by VacA. In cells transiently transfected with a GTPase-defective (dominant-negative) dynamin mutant, VacA failed to induce vacuolation. In contrast, VacA did induce vacuolation in cells transiently transfected with wild-type dynamin. Furthermore, under VacA treatment, neutral red dye uptake, a parameter of VacA-induced vacuolation, was inhibited in cells stably transfected with the dominant-negative dynamin mutant. In contrast, uptake was markedly enhanced in cells stably transfected with wild-type dynamin. Moreover, VacA cytopathic effects on the viability of HeLa cells were inhibited in cells stably transfected with dominant-negative dynamin-1. Sequential immunocytochemical observation confirmed that expression of dominant-negative dynamin did not affect VacA attachment to or internalization into HeLa cells. We suggest that dynamin is involved in the intracellular vacuolation induced by VacA.

Bacterial Proteins↗
PubMed2001

Evaluation of the effective drugs for the prevention of nausea and vomiting induced by morphine used for postoperative pain: a quantitative systematic review.

Postoperative nausea and vomiting (PONV) with morphine therapy develops in more than 60% of patients after surgery, markedly reducing patient QOL. The prophylactic effect of several antiemetics has already been studied, but evaluations, and even those using the same drug, are not uniform. The present research involved a meta-analysis of randomized controlled trials on prophylactic drug therapy for PONV in patients receiving morphine for the treatment of postoperative pain. The efficacy of the prophylactic administration of the drugs was examined. As a result, meta-analysis of five drugs was possible and the evidence of efficacy was shown for three drugs ranked in order of an increasing odds ratio (OR) and confidence interval (CI): dexamethasone (OR: 0.23, 95% CI: 0.15-0.35, p < 0.00001), droperidol (OR: 0.27, 95% CI: 0.21-0.34, p < 0.00001), and metoclopramide (OR: 0.48, 95% CI: 0.30-0.75, p < 0.001). These results suggest that the three drugs are effective in prophylactic treatment for PONV. Of them, dexamethasone used as a prophylactic drug for PONV provided the best results. Dexamethasone was shown to reduce the incidence of PONV from 66-80% to 16-50% with a dose of 1.25 to 10 mg and to be suitable as a first drug of choice.

Antiemetics↗
PubMed2001

[A case of a left atrial primary malignant fibrous histiocytoma].

Primary malignant fibrous histiocytoma (MFH) of the heart is very rere. We report a case of a primary intracardiac MFH. A 50-year-old woman underwent an operation for congestive heart failure due to left atrial (LA) tumor. Cardiac echocardiogram showed the tumor attached to the septal wall and posterior wall of LA. We extendedly resected the tumor with septal and partially posterior wall and reconstructed there with pericardial substitute. Pathological diagnosis was MFH. Although she did well postoperatively, cardiac echocardiogram showed a recurrent tumor in the LA at 10 days after operation. She developed respiratory failure, and chest and abdominal CT demonstrated metabolism to the lung, liver and bladder at post operative 47 days. At 77 days after operation, she expired. The prognosis of MFH is poor despite surgery. We recommend extended surgery, if the LA tumor had wide base attached to the septal or posterior wall.

Echocardiography↗
PubMed2001

[Clinical effects of meropenem on infectious diseases in obstetrics and gynecology].

The efficacy and the safety of meropenem (MEPM) were examined in obstetric and gynecological infections and the results shown below were obtained. 1. The subjects were patients with infectious diseases during a non-pregnant period (n = 14), a pregnant period (n = 13) and a puerperal period (n = 11). After intravenous drip infusion of MEPM at 1-2 g/day, the response rate was 38/39 (97.4%) (Excellent: 13/39 (33.3%), Effective: 25/39 (64.1%)). 2. The response rates in a group receiving 1 g/day, a group receiving 2 g/day and a group receiving a combination of both were, respectively, 25/26 (96.2%), 9/9 (100%) and 4/4 (100%). 3. In cases that did not respond to previous treatments, the response rate to MEPM was 20/20 (100%). 4. In clinical efficacy classified by causative organisms, the rate of Excellent was 10/23 (43.5%) and the rate of Effective was 13/23 (56.5%), and the bacterial eradication rate was 21/23 (91.3%). 5. No subjective and objective adverse reactions or abnormalities in clinical laboratory tests due to administration of MEPM were observed.

Adult↗
PubMed2001

[Clinical investigation of cefpirome for perinatal infection and infection prevention].

Effectiveness and safety of cefpirome (CPR) were studied in perinatal infection and prevention of postoperative infections. 1. Enrolled in the study of perinatal infections were the total 62 cases comprising 47 of chorioamnionitis, 10 of puerperal intrauterine infections, 1 of infectious abortion and 4 of others. The effective rate of CPR 2 g/day given in drip infusion was 61/62 (98.4%). In bacteriological studies, the bacterial elimination rate was 57/61 (93.4%). Unchanged and remained were 3 strains of Gram-positive bacteria and 1 strain of Bacteroides spp. 2. Enrolled in the study of prevention of postoperative infections during perinatal period were the total 88 cases comprising 74 who underwent cesarean section and 14 others. The effective rate of CPR 2 g/day given in drip infusion was 87/88 (98.9%). 3. With respect to subjective and objective adverse affects due to the agent, drug eruption was observed in 1/150 (0.7%). No abnormal result of clinical laboratory tests was found. The above results suggested the usefulness of CPR for treatment of perinatal infections and prevention of postoperative infections.

Adult↗
PubMed2001

[Postoperative right ventricular function after repair of tetralogy of Fallot with respect to the method of right ventricular outflow tract reconstruction].

We evaluated postoperative right ventricular function in the sixty-four consecutive patients with tetralogy of Fallot underwent total correction. The patients were divided to three groups according to the method of right ventricular outflow tract reconstruction: transannular patching (TA group; n = 31); right ventricular outflow patching with preservation of pulmonary valve ring (RV group; n = 12) and transatrial-transpulmonary approach without right ventriculotomy (no-RV group; n = 21). The early results of postoperative cardiac catheterization and echocardiography were compared among the three groups. Degree of pulmonary regurgitation was significantly low in the RV group and no-RV group compared with TA group (p < 0.005). Right ventricular ejection fraction was the highest in the no-RV group (p < 0.002). The repair without right ventriculotomy for tetralogy of Fallot can provide the best results with respect to postoperative right ventricular function.

Cardiac Surgical Procedures↗
PubMed2001

[Survival after oozing type cardiac rupture associated with subepicardial aneurysm evaluated by echocardiography: a case report].

A 64-year-old woman was admitted to our hospital with acute myocardial infarction. She underwent emergent percutaneous transluminal coronary angioplasty. Transthoracic echocardiography revealed mild pericardial effusion on the third day. Pericarditis or cardiac rupture were suspected, so transthoracic echocardiography was repeated serially. On the sixth day, transthoracic echocardiography showed increasing pericardial effusion and abrupt interruption of the apical myocardium of the left ventricle and intact epicardial imaging with systolic expansion. The diagnosis was oozing type cardiac rupture of a subepicardial aneurysm. Surgical treatment was successful and the accuracy of the echocardiographic diagnosis was established.

Angioplasty, Balloon, Coronary↗
PubMed2001

[Surgical management of non-tuberculous mycobacteriosis and tuberculosis of the lung].

From 1990 to 1999, three patients with non-tuberculous mycobacteriosis and 14 patients of tuberculosis underwent pulmonary resection in the National Sanatorium Ehime Hospital. Of the patients with tuberculosis, two were multiple drug-resistant cases and twelve cases were suspected of lung cancer before diagnostic resection. All three patients with non-tuberculous mycobacteriosis were symptomatic, had chest cavities in the lung, and were sputum-culture positive. There were no operative death in all patients, and one case of post-operative complication. Two patients, one with non-tuberculous mycobacteriosis and another with tuberculosis, failed in sputum negative conversion. The former had been treated for a long time preoperatively. Early resection in patients of pulmonary non-tuberculous mycobacteriosis and of pulmonary multiple drug-resistant tuberculosis is recommended to prevent further progression of pulmonary lesions.

Adult↗
PubMed2001

Estimation of vacuolating cytotoxin secreted by different strains of Helicobacter pylori using bead enzyme-linked immunosorbent assay & its correlation with bacterial genotype.

BACKGROUND & OBJECTIVES: A highly sensitive bead enzyme-linked immunosorbent assay was applied for the quantitative determination of vacuolating cytotoxin (VacA) released in the culture supernatant of 40 well characterized Helicobacter pylori strains in order to clarify the significance of allelic combination of the vacA gene as the predictor of the level of toxin secretion and also to determine the most appropriate genotype of H. pylori associated with high VacA release. Attempts were also made for the detection of VacA in the gastric juice of patients for the rapid diagnosis of H. pylori infection. METHODS: The genotypes of 40 H. pylori strains cultured from the gastric biopsy samples were determined by specific PCRs. The cell-free culture supernatant of the strains as well as the gastric juice of the patients were used for bead-ELISA and the purified VacA from the H. pylori strain ATCC49503 was used as positive control. RESULTS: Ninety per cent of the strains with vacAs1m1 allele combination secrete on an average 146.4 ng/ml of VacA while the corresponding value was 19.1 ng/ml for s1m2 strains. None of the s2m2 as well as the ice negative H. pylori strains produced detectable VacA in the medium while strains expressed the toxin irrespective of the presence or absence of cagA gene. Fifteen of 22 gastric juice samples yielded positive bead-ELISA results. INTERPRETATION & CONCLUSION: vacAs1, vacAm1 and iceA1 could be considered as the determinants of high VacA secretion. Also, the detection of VacA by bead-ELISA in the gastric juice could be considered as an alternative approach in the diagnosis of H. pylori infection.

Adult↗