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Biomedical subjects

T Azuma

Publications and source records attributed to T Azuma.

At least 55 records · Page 3Linked to original sources
PubMed1995

A new nitric oxide (NO) releaser: spontaneous NO release from FK409.

The remarkable vasorelaxant and anti-platelet effects of FK409 have been reported to be due to nitric oxide (NO) release. The purpose of the present study is to investigate the spontaneous NO-releasing pathway of FK409 in aqueous solutions. 1H-NMR spectra of FK409 suggested that the compound underwent a time-dependent elimination of the hydrogen atom at alpha-position of the nitro moiety (at the 5-position) in weakly alkaline solutions. In addition, the degradation of FK409 monitored by HPLC showed a pH-dependency accelerating with an increase of pH. These results revealed that the first step in the degradation of FK409 might be the hydroxyl ion-dependent subtraction of the hydrogen atom at the 5-position. On the other hand, NO release from FK409 also exhibited a pH-dependency, and the velocity of NO liberation was markedly enhanced above pH 6. Furthermore, a linear relationship between the rate of FK409 degradation and that of NO formation was observed, indicating that the rate-limiting step for NO formation is the same as that for degradation. Thus, the rate-limiting process of NO formation from FK409 is due to the deprotonation reaction of the hydrogen atom at the 5-position by hydroxyl ions. The deprotonation process appears to be an essential step for both FK409 degradation and NO release. On the basis of the results, a possible kinetic scheme for NO release from FK409 is proposed.

Buffers↗
PubMed1995

Antagonistic peptides against human anaphylatoxin C5a.

Multivalent synthetic peptides derived from C5a were prepared in order to examine their effects on the C5a receptor (C5aR). Multiple antigen peptide (MAP) of the C5a C-terminal region (MAP61-74) bound to cells expressing C5aR with high affinity. On the other hand, N-terminal peptides (MAP3-16 and MAP12-26) and one with a sequence from the mid-portion of C5a (MAP37-53) did not bind to the cells. In addition, MAP61-74 inhibited Ca2+ mobilization and release of beta-hexosaminidase by C5a from dibutyryl cAMP-activated U937 cells. This Ca2+ mobilization was also inhibited by MAP12-26 and Mono61-74, the monomeric C-terminal peptide. Taken together, these data indicate that C5a binds to the C5aR via its C-terminal region. Furthermore, MAP61-74, a 14mer peptide that has additional amino acids at the N-terminal compared with the C-terminal octapaptide, can bind to C5aR and can be considered an antagonist of C5a which may prove useful as an agent for controlling the allergic response caused by complement activation.

Amino Acid Sequence↗
PubMed1995

[AIDS control in industry in Okinawa Prefecture, Japan].

To see how industry is responding to AIDS, an anonymous questionnaire survey was conducted on member companies (n = 407) of the chamber of commerce with 50 or more employees in three large cities in Okinawa, during February to March, 1994. Responses were obtained from 221. The questionnaire looked at type of industry, number of employees, number of business trips to foreign countries, specialists for health management, AIDS control, attitudes and actions taken toward infected persons and AIDS patients, etc. The main results were as follows; In 73 companies foreign business trips had been made. The rate of appointment of specialists in health management was below 50%. In 80% of the companies, AIDS control was not in place. About 1/2 of the companies responded that there was a need to grapple with AIDS control while 40% of the companies were undecided. The majority of the companies felt that there was no chance of their employees having HIV infection within five or six years. Many companies had no regulations for dealing with employees who are infected with HIV. From the survey, three points were made clear: 1. Industry does not have an adequate plan to deal with AIDS. 2. There is no awareness of a crisis. 3. There is insufficient dissemination of information regarding AIDS. HIV/AIDS is predicted to increase in industries in our country and management will be hard-pressed to deal with the intricate problems that arise. HIV/AIDS is not exclusively an individual problem, but should be the concern of industries and society as well.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Measures for infection in multiple myeloma].

A peculiarity of infection, as a complication of multiple myeloma in hematopoietic malignancies, is discussed. The Hanshin Study Group of Hematopoietic Disorders and Infection treated 3346 cases of bacterial infection during the past 13 years. Myeloma patients showed a low rate of 3.0% as compared with 28.2% of acute myelogenous leukemia patients. In patients with long term administration of antibiotics or bone marrow suppression, it is necessary to watch for fungus infection. Recently, new combination chemotherapy (DMVM-IFN alpha) is widely used in Japan. A high complete remission rate has been achieved by this regimen, but the incidence of infection tends to increase. Measures for infection in multiple myeloma should therefore be similar to that acute leukemia.

Bacterial Infections↗
PubMed1995

Immunogenetic analysis of the human leukocyte antigen DQA1 locus in patients with duodenal ulcer or chronic atrophic gastritis harbouring Helicobacter pylori.

AIM: To examine the human leukocyte antigen (HLA)-DQA1 locus in patients harbouring Helicobacter pylori with chronic atrophic gastritis or duodenal ulcer as part of an investigation into immunogenetic differences in the host. SUBJECTS AND METHODS: We examined 116 patients harbouring H. pylori (55 patients with chronic atrophic gastritis, 61 with duodenal ulcers) and 28 H. pylori-negative healthy controls for HLA-DQA1 genotypes. H. pylori infection was determined by culturing biopsy samples from the gastric body and antrum and by enzyme-linked immunosorbent assay. HLA-DQA1 typing was carried out by the polymerase chain reaction-restriction fragment length polymorphism method. RESULTS: The allele frequency of DQA1*0102 was significantly higher in H. pylori-negative controls (0.250) than in H. pylori-positive duodenal ulcer patients (0.090). In contrast, the allele frequency of DQA1*0301 was significantly lower in H. pylori-negative controls (0.214) than in H. pylori-positive duodenal ulcer patients (0.418). CONCLUSION: These results suggest that there are genetic differences in the HLA-DQA1 locus between H. pylori-positive duodenal ulcer patients and H. pylori-negative healthy controls.

Adult↗
PubMed1995

Differences in urease activity in live Helicobacter pylori cultured from patients with gastroduodenal diseases.

AIM: To develop a reliable method for measuring urease activity in live bacteria, and to determine whether there are any differences in urease activity among the Helicobacter pylori strains involved in gastroduodenal disease. DESIGN: The stability of the method was examined in the first phase of the study, and in a second phase the mean urease activity in clinical isolates from different groups of patients was compared. MATERIALS AND METHODS: To assess the stability and reliability of the method, we assessed the relationship between bacterial proliferation and urease activity, the relationship between the number of bacteria and the optical density, and differences in urease activity among bacterial generations. Ten of the 3-day-old colonies in the third generation were suspended in phosphate-buffered saline, and urease activity was measured as 10(5) colony-forming units/ml bacteria. RESULTS: The assay system appeared to be effective, because the urease activity of live bacteria in the logarithmic growth period was constant, the number of bacteria and the optical density showed a linear correlation on a bilogarithmic graph and there was no significant difference in urease activity over three generations. With this method, urease activity varied from 0.192 to 80.42 mIU/10(5) colony-forming units of bacteria/ml. There was no significant difference in the mean urease activity of live bacteria from controls, gastric ulcer patients and duodenal ulcer patients. However, the mean urease activity in bacteria from cancer patients was significantly higher than that of controls or duodenal ulcer patients. CONCLUSIONS: H. pylori strains derived from cancer patients, which have relatively high levels of urease activity, might easily colonize the stomach and lead to much mucosal damage during the long course of H. pylori infection.

Adult↗
PubMed1995

Genetic differences between duodenal ulcer patients who were positive or negative for Helicobacter pylori.

This study investigated genetic differences between Helicobacter pylori-positive and -negative duodenal ulcer patients. Seventy-two patients with duodenal ulcer (61 H. pylori positive and 11 H. pylori negative) were examined for HLA-DQA1 genotype. The allele frequency of DQA1*0102 was higher in H. pylori-negative than in H. pylori-positive patients. Moreover, the genotypes that possessed the DQA1*0102 allele were significantly more common in H. pylori-negative than in H. pylori-positive patients. In contrast, the allele frequency of DQA1*0301 was lower in H. pylori-negative than H. pylori-positive patients. The genotypes that possessed DQA1*0301 were significantly more common in H. pylori-positive than in H. pylori-negative patients. These results suggest that there are genetic differences between H. pylori-positive and -negative duodenal ulcer patients and that immunogenetic factors for susceptibility or resistance to H. pylori infection exist in the host.

Adolescent↗
PubMed1994

Expression of the interleukin-6 (IL-6), IL-6 receptor, and gp130 genes in acute leukemia.

Expression patterns of interleukin-6 (IL-6), IL-6 receptor (IL-6R), and gp130 genes in 39 patients with acute myeloid leukemia (AML), in 23 patients with acute lymphoblastic leukemia (ALL), and in 7 patients with acute mixed lineage leukemia (AMLL) were studied by quantitative reverse transcriptase-polymerase chain reaction. Significant levels of IL-6 were expressed in 8 (21%) of 39 AML patients and in 2 (29%) of 7 AMLL patients, whereas in ALL, the expression of IL-6 was almost negligible. IL-6R was expressed in all patients with AML and AMLL, whereas only half of ALL patients expressed low levels of IL-6R as compared with those with AML and AMLL. However, gp130 was ubiquitously expressed in all the leukemia patients, and there was no significant difference in gp130 expression among AML, ALL, and AMLL. Significant correlation was observed between the expression of IL-6R and gp130 in AML. When tested for in vitro response to IL-6, the leukemic cells from 3 of 7 AML, none of 3 ALL, and both of 2 AMLL patients significantly responded to IL-6, showing the correlation between the expression levels of IL-6R and gp130 and the responsiveness of leukemic cells to IL-6. These results showed that quantitation of IL-6R and gp130 expression by reverse transcriptase-polymerase chain reaction is useful for the rapid prediction of the responsiveness of leukemic cells to IL-6, especially in cases of administration of IL-6.

Adolescent↗
PubMed1994

Isolation of the bile canalicular actin-myosin II motor.

Cytoskeleton-rich canalicular membranes (CCMs) with preserved cytoskeleton and demembranated CCMs, consisting only of cytoskeletal elements, were used to examine the relationship of pericanalicular microfilaments, myosin II phosphorylation, and canalicular contraction. The components of CCMs were visualized by fluorescence microscopy using the filamentous actin probe rhodamine-phalloidin and by electron microscopy, before and after incubation in 1 microM Ca2+/1 mM ATP (contraction solution). Canalicular contraction (luminal closure) was evaluated by morphometric analysis. Myosin II was extracted from CCMs, purified by immunoprecipitation, and analyzed on Western blots. In sequential experiments, autoradiographs of gels from [gamma-32P]-ATP-treated CCMs in the presence or absence of Ca2+ were examined after 0.25, 0.50, 1, 2, 3, 5, and 10 min, and the effects of W7 (a calmodulin antagonist) and ML9 (a myosin light chain kinase inhibitor) were evaluated. The results showed that phosphorylation of the 20-kDa protein was low in controls but enhanced beginning 0.25-0.50 min after addition of contraction solution. Both W7 and ML9 significantly inhibited this reaction and inhibited canalicular contraction. The results indicate that phosphorylation of the regulatory 20-kDa myosin light chain of canaliculus-associated myosin II coincides with or precedes contraction of the canaliculus. We conclude that the canalicular contractile apparatus is composed of actin filaments and a myosin II motor.

Actins↗
PubMed1994

The gene responsible for LEC hepatitis, located on rat chromosome 16, is the homolog to the human Wilson disease gene.

We identified the rat homolog to the human Wilson disease (WD) gene as the gene responsible for hepatitis (hts) in the Long Evans Cinnamon (LEC) rat. A genetic study using fifty-three backcross progenies showed that the rat WD gene detected by Southern blotting using the human WD gene as a probe was tightly linked to the hts phenotype of the LEC rat with no recombination. LEC is a transcriptionally deficient mutant because no transcript of the rat WD gene could be found in the LEC rat by Northern blotting. This rat WD gene was mapped to 16q12.23-12.3 by fluorescence in situ hybridization and mouse x rat somatic cell hybrid analysis.

Animals↗
PubMed1994

Secretion of human intracellular aspartic proteinase cathepsin E expressed in the methylotrophic yeast, Pichia pastoris and characterization of produced recombinant cathepsin E.

The human gastric cathepsin E (CTSE), a dimeric aspartic proteinase, was expressed in the methylotrophic yeast Pichia pastoris by placing the CTSE cDNA under the control of the methanol inducible alcohol oxidase promoter. The human CTSE expressed in P. pastoris was secreted into the culture medium as an active enzyme directed by its native signal sequence despite its intracellular localization in mammalian cells. The time course analysis of the culture supernatant of the P. pastoris transformant expressing human CTSE revealed that the recombinant human CTSE was secreted as a 90 kDa molecule and then converted via an 84 kDa intermediate to an 82 kDa mature molecule. A large-scale culture of the transformant was performed in a high cell density fermentor and the recombinant human CTSE was highly purified from the culture supernatant. The purified recombinant cathepsin E had the molecular mass of 82 kDa with the amino-terminal sequence starting with Ile37 of the sequence deduced from its cDNA sequence, suggesting that the human cathepsin E was accumulated in the culture supernatant as mature dimeric enzyme. The result of endoglycosidase-H digestion followed by Western blot analysis of the purified recombinant cathepsin E suggested that the human cathepsin E expressed in P. pastoris received N-linked high-mannose type glycosylation. The enzymatic properties of the recombinant enzyme were comparable to those of natural human CTSE.

Base Sequence↗
PubMed1994

Comparison of somatic mutation frequency among immunoglobulin genes.

We analyzed the frequency of somatic mutation in immunoglobulin genes from hybridomas that secrete anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) monoclonal antibodies. A high frequency of mutation (3.3-4.4%) was observed in both the rearranged VH186.2 and V lambda 1 genes, indicating that somatic mutation occurs with similar frequency in these genes in spite of the absence of an intron enhancer in lambda 1 chain genes. In contrast to the high frequency in J-C introns, only two nucleotide substitutions occurred at positions -462 and -555 in the 5' noncoding region in one of the lambda 1-chain genes and in none of the other three so far studied. Since a similar low frequency of somatic mutation was observed in the 5' noncoding region of inactive lambda 2-chain genes rendered inactive because of incorrect rearrangement, this region may not be a target or alternatively, may be protected from the mutator system. We observed a low frequency of nucleotide substitution in unrearranged V lambda 1 genes (approximately 1/15 that of rearranged genes). Together with previous results (Azuma T., N. Motoyama, L. Fields, and D. Loh, 1993. Int. Immunol. 5:121), these findings suggest that the 5' noncoding region, which contains the promoter element, provides a signal for the somatic mutator system and that rearrangement, which brings the promoter into close proximity to the enhancer element, should increase mutation efficiency.

Animals↗
PubMed1994

High prevalence of neutralizing activity to Helicobacter pylori cytotoxin in serum of gastric-carcinoma patients.

Helicobacter pylori infection is causally related to chronic type-B gastritis, and may also be associated with an increased risk of gastric carcinoma. Vacuolating cytotoxin, which is an 87-kDa protein secreted by H. pylori, induces eukaryotic cell vacuolation in vitro. To determine whether there is an association between H. pylori vacuolating cytotoxin and gastric carcinoma, we investigated several characteristics of H. pylori infection, i.e., isolation of H. pylori from gastric biopsies, antibodies specific for H. pylori, detection of neutralizing activity to vacuolating cytotoxin in serum and immunological detection of cytotoxin by serum. Out of 6 sera from gastric-carcinoma patients, all showed the neutralizing activity to vacuolating cytotoxin, in contrast to 3 of 5 sera from peptic-ulcer patients. Normal individuals showed no neutralizing activity. All sera possessing the neutralizing activity recognized an 87-kDa protein band by Western blot analysis. Our results confirmed that cytotoxin-neutralizing activity in human sera was associated with immunodetection of an 87-kDa protein. To further evaluate neutralizing activity in serum from gastric-carcinoma patients, we retrospectively analyzed frozen-stocked serum samples from 22 gastric-carcinoma patients. Sera from 21 of these 22 patients exhibited neutralizing activity. These sera were also checked for antibodies to H. pylori, using an ELISA; 16 sera showed positive results. Our results indicate that detection of cytotoxin-neutralizing activity in sera is strongly associated with H. pylori infection, and probably with gastric carcinoma, and is also of interest in the diagnosis of H. pylori infection.

Adult↗
PubMed1994

Histological studies on the rheumatoid synovial membrane irradiated with a low energy laser.

The beneficial effects of low energy laser irradiation on rheumatoid arthritis (RA) joints have been reported, but the mechanisms of action of low energy lasers in RA are unclear. The synovial membrane in cases of RA was studied histologically to observe the effects of low energy laser irradiation. Fourteen knee joints of RA cases, which had been scheduled for arthroplasty, were irradiated with a gallium-aluminium-arsenide (Ga-Al-As) laser (790 nm in wavelength and 10 mW of output power) prior to the surgical operation, at six points of the external aspect of the knee joint for 80 seconds at each points once a day for 6 days. On the day following the last irradiation, pieces of synovial membrane from the lateral irradiated area and from the median nonirradiated area as a control were resected during the arthroplasty. The histological findings of the irradiated synovial membrane showed flattening of epithelial cells, decreased villous proliferation, narrowed vascular lumen, and less infiltration of inflammatory cells compared with those of nonirradiated synovia. The evaluation of slides was done in a blinded manner, and significant differences was seen by Wilcoxon's t-test (P < 0.01). Histological findings suggested that the low energy laser irradiation induced suppression of inflammation in the synovial membrane of RA.

Arthritis, Rheumatoid↗
PubMed1994

The effect of donor-specific transfusion and cyclosporin A on small bowel transplantation in the rat.

Pre-transplant blood transfusions are given as a means of desensitization to reduce the required dose of cyclosporin A (CsA). In this study, the effect of pretransplant blood transfusion on host survival and T-cell function against alloantigen were investigated. Male Lewis rats (RT1(1)) were used as the recipients in all experiments, and male DA rats (RT1a) were used as the blood and small bowel donors, and as a source of allogeneic stimulator cells. Male BUF rats (RT1b) were used as donors of third party blood, and of allo-stimulator cells in a delayed-type hypersensitivity (DTH) response. In our experimental design, Lewis rats were divided into the following groups according to the type of administration: (1) a donor-specific blood transfusion (DST) 8 days preoperatively and a concurrent 5-day course of CsA at 10 mg/kg per day; (2) a nonspecific third party blood transfusion (NST) and CsA at 10 mg/kg per day from day 8 to day 4 preoperatively; (3) CsA alone from day 8 to day 4 preoperatively; (4) DST alone 8 days preoperatively; or (5) no treatment, being the control group. Postoperative treatment consisted of CsA at 2.5 mg/kg per day for 30 days. Rats conditioned with NST plus CsA, CsA alone, DST alone, and the untreated control rats survived for 7.2 +/- 1.2, 9.0 +/- 2.2, 6.8 +/- 0.4, and 7.4 +/- 1.6 days, respectively. In contrast, the five rats conditioned with DST plus CsA survived for 100 days or more.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A case of quadruplet pregnancy containing complete mole and three fetuses.

A case of a quadruplet pregnancy containing a complete mole and three fetuses is reported. A 29-year-old Japanese woman who had received clomiphene therapy was delivered of a complete mole, one dead and two living fetuses, and three placentas. Deoxyribonucleic acid fingerprint analysis proved the androgenesis of molar tissue and the trizygosity of the three fetuses.

Adult↗
PubMed1994

A case of ovarian Brenner tumor with stromal estrogenic activity.

An 88-year-old menopausal Japanese female suffering from atypical genital bleeding received a left oophorectomy for a tumor of the left ovary. A vaginal smear before removal of the tumor revealed high estrogenic activity. The patient's ovarian tumor was a benign Brenner tumor and contained theca-like cells in its stroma. The pathological findings relating to these theca-like cells suggested their estrogenic activity, and a vaginal smear after removal of the tumor revealed that estrogenic activity had disappeared.

Aged↗