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T Azuma

Publications and source records attributed to T Azuma.

At least 163 records · Page 9Linked to original sources
PubMed1996

Biochemical properties of the monomeric mutant of human cathepsin E expressed in Chinese hamster ovary cells: comparison with dimeric forms of the natural and recombinant cathepsin E.

Cathepsin E (CE) is the only known aspartic proteinase that exists as a homodimer consisting of two fully catalytically active monomers, which are covalently bound by a disulfide bond between two cysteine residues at the NH2-terminal region (Cys43 in human pro-CE). To understand the physiological significance of the dimer formation, the monomeric mutant of human CE was constructed by site-directed mutagenesis (Cys43 ->Ser43) and expressed in Chinese hamster ovary (CHO) cells. Immunolocalization of the mutant protein at both the light and electron microscopic levels revealed the monomeric CE to be associated predominantly with the endoplasmic reticulum and the non-lysosomal endocytic organelles. The cellular localization of the monomeric protein was compatible with that of the wild-type (dimeric form) of recombinant human CE expressed in the same cells. The monomeric protein was generated primarily as the 46-kDa pro-CE with a high-mannose-type oligosaccharide chain in the cells. In addition to the maximal activation at around pH 3.5, a substantial proportion of the monomeric pro-CE was converted to the mature form by incubation at pH 7 and 37 degrees C for 5 min. In contrast, the dimeric pro-CE was scarcely activated by treatment at pH7. Although catalytic properties of the in vitro-activated monomeric CE appeared to be indistinguishable from those of the dimeric forms of natural and recombinant CE, the monomeric form was more unstable to pH and temperature changes than these dimeric forms. These results indicate that the dimerization of CE is not necessarily required for proper folding to express activity, correct intracellular localization and carbohydrate modification, but that it may be essential to structurally stabilize the molecule in vivo.

Amino Acid Sequence↗
PubMed1996

Cross-sectional analysis of Alzheimer disease effects on oral discourse in a picture description task.

To examine the relation of dementia severity to the quality and quantity of oral discourse of individuals with Alzheimer disease (AD), a picture description task was administered to elicit oral discourse samples from 63 AD subjects, five individuals with very mild cognitive impairment, and 52 normal controls. Eight measures of discourse were used: total words, information units, conciseness, circumlocutions, frustrations, aborted phrases, revisions, and ideational repetitions. Information units, which decreased with increased dementia severity, proved to be the best measure for evaluating the effects of AD on oral descriptive discourse. The conciseness index also decreased with increased dementia severity, and a significantly greater proportion of AD discourse samples contained ideational repetitions. Circumlocutions and frustrations rarely occurred, and although the discourse of AD subjects was more likely to contain an aborted phrase, the frequency of aborted phrases did not vary by stage of dementia. Revisions were commonly observed in the discourse of both normal controls and AD subjects and did not differentiate the two groups.

Aged↗
PubMed1996

Cytotoxin and urease activities of Helicobacter pylori isolates from Japanese patients with atrophic gastritis or duodenal ulcer.

The vacuolating cytotoxin and urease secreted by Helicobacter pylori are thought to be virulent factors. Because vacuolation is potentiated by the presence of ammonium ion, which is produced by urease in vitro, it is of interest to examine whether cytotoxin and urease work reciprocally in the development of atrophic gastritis or duodenal ulcer. In the present study, patients (all H. pylori-positive) were divided into four groups: mild atrophic gastritis (group 1; nine patients), severe atrophic gastritis (group 2; 36 patients), duodenal ulcer with mild atrophic gastritis (group 3; 19 patients) and duodenal ulcer with severe atrophic gastritis (group 4; 12 patients). Cytotoxin production and urease activity of H. pylori isolated from these patients were analysed. Cytotoxin production was observed in four of nine (44.4%), 28 of 36 (77.8%), 11 of 19 (57.9%) and eight of 12 (66.7%) isolates from groups 1, 2, 3 and 4, respectively. Cytotoxin-producing H. pylori isolates were found significantly more in patients with severe atrophy than in patients with mild atrophy (P = 0.048). The mean of relative activity of cytotoxin in H. pylori isolate was 1.6 +/- 2.3, 7.9 +/- 7.4, 5.8 +/- 6.0 and 9.0 +/- 9.1 in groups 1, 2, 3 and 4, respectively. Helicobacter pylori isolates from severe atrophy or duodenal ulcer patients in groups 2 or 4 possessed significantly higher activity than those from non-ulcer patients in group 1 (P = 0.017 and 0.030, respectively). The mean of urease activity was 8.6 +/- 4.6, 10.0 +/- 5.9, 10.0 +/- 8.5 and 11.2 +/- 7.7 IU/mg in groups 1, 2, 3 and 4, respectively. These differences indicated no statistical significance. In each H. pylori isolate, the production of cytotoxin and urease were independent, which indicated that there was no reciprocal effect between them in vivo. Thus, cytotoxin-producing H. pylori isolates were more prevalent in patients with severe atrophic gastritis and the cytotoxin activities of H. pylori isolates from the patients with severe atrophic gastritis or duodenal ulcer were much higher than those from the patients with mild atrophic gastritis, which suggested that vacuolating cytotoxin may be a disease-inducing factor.

Bacterial Proteins↗
PubMed1996

Diagnosis of Helicobacter pylori infection.

A number of diagnostic tests have been developed for the detection of H. pylori. Diagnostic techniques can be divided into invasive and noninvasive methods. The invasive methods require upper gastrointestinal endoscopy and involve culture of gastric biopsy specimens, examination of stained biopsies and detection of urease activity in the biopsies themselves. In addition, we have developed endoscopic diagnosis of H. pylori infection in gastric mucosa using phenol red dye-spraying. The noninvasive methods include urea breath test and serological techniques. Although there has been considerable improvement in the techniques, a combination of at least two different techniques should be used in order to optimize the diagnostic yield. We recommend the use of one rapid test in the combination. The rapid urease test, cytology and the phenol red dye-spraying endoscopy give results available before the patient leaves the endoscopy suite.

Helicobacter Infections↗
PubMed1996

Human pregnancy serum suppresses the proliferative response of lymphocytes to autologous PHA-activated T lymphoblasts.

PROBLEM: We have previously demonstrated that human serum can suppress the proliferative response in autologous mixed lymphocyte reaction (AMLR) in which phytohemagglutinin (PHA)-activated T lymphoblasts act as stimulators (T-TPHA AMLR). The aim of the present work was to determine whether pregnancy serum (PS) possesses an inhibitory capacity similar or different in magnitude. METHODS: Sixteen PS were added to T-TPHA AMLR cultures and the proliferative response was compared with that in the presence of human serum. The effect of PS on the IL-2 dependent proliferation of PHA-activated T Lymphoblasts was examined as well. RESULTS: PS induced a significantly more pronounced suppression of T-TPHA AMLR than human serum (P < 0.05). One PS tested was not inhibitory but rather stimulatory. This PS was obtained from a woman who subsequently had IUGR. The inhibition is related to the existence of a serum inhibitory factor and not to the lack of a serum supporting factor. PS inhibited not only T-TPHA AMLR of the same woman but also T-TPHA AMLR of other individuals as well, implying that the inhibitor is a non-MHC restricted factor. IL-2 dependent cell proliferation was not inhibited by PS, implying that the inhibitor detected in T-TPHA AMLR is not a general cell proliferation inhibitor. CONCLUSIONS: These results suggest that a non-MHC restricted inhibitory factor present in PS may play an important biological role in regulating local immune responses in the fetal-placental unit mediated by autoreactive T cells restricted to autologous activated T lymphocytes.

Antilymphocyte Serum↗
PubMed1996

Cellular uptake and biological effects of antisense oligodeoxynucleotide analogs targeted to herpes simplex virus.

In this study, we synthesized antisense oligodeoxynucleotides (ODNs) with phosphodiester, phosphorothioate (S-ODNs), or methylphosphonate linkages complementary to the splicing acceptor site of immediate-early pre-mRNA 5 of herpes simplex virus type 1 (HSV-1). The antiviral activity of each analog on cytopathic effect in cells infected with HSV-1 or HSV-2 was assessed and compared with the cellular uptake of the analog. We found that antisense S-ODNs showed the most potent antiherpetic activity, with 50% inhibitory concentrations of 5 microM for HSV-1 and 0.25 microM for HSV-2. The antiviral effect of antisense S-ODNs was stronger and longer acting than that of acyclovir. Cell association of S-ODNs was the highest and paralleled antiviral activity. Furthermore, some fluorescein isothiocyanate (FITC)-labeled S-ODNs were recognized in the nuclei in HSV-1 infected cells by confocal laser scanning microscopy. S-ODNs located in the nucleus could access the targeted mRNA, which might be responsible for the antiviral activities. Although our study also showed non-sequence-specific activity, which implies that multiple mechanisms are involved, S-ODNs are a promising novel anti-herpetic agent.

Animals↗
PubMed1996

Profile of Helicobacter pylori cytotoxin derived from two areas of Japan with different prevalence of atrophic gastritis.

BACKGROUND AND AIM: To clarify the roles of Helicobacter pylori cytotoxin in gastric atrophy, the cytotoxin positive rate and cytotoxin activity in Fukui and Okinawa, where the prevalence of atrophic gastritis and gastric cancer risk are quite different, were studied. MATERIALS: Seventy three strains from Fukui and 51 from Okinawa were examined. METHODS: The validation of atrophy was done by endoscopy, being confirmed with histology. The supernatant of liquid H pylori culture media was concentrated 20-fold, serially diluted, using doubling dilutions, and scored from 1 to 8. The semi-quantitated cytotoxin activity was expressed as the maximum dilution score yielding > 50% A431 cell vacuolation, being standardised with bacterial density. RESULTS: The cytotoxin activity of the strains from Fukui was highly diverse compared with that from Okinawa, although the cytotoxin positive rate was not different. In Fukui strains, the grade of atrophy and the cytotoxin activity were correlated (p < 0.05). In addition, the cytotoxin activity of the strains from all patients in Okinawa, most of whom showed closed-type/mild atrophy, was significantly lower than that of the strains from the patients with open-type/severe atrophy in Fukui (6.46 (5.53) v 9.76 (8.80), p < 0.05), (mean (SEM)). CONCLUSION: The difference in profile of the cytotoxin activity in the two areas was related to the difference in the prevalence of atrophic gastritis.

Adult↗
PubMed1996

[Thoracoscopic extended thymectomy in conjunction with a collar incision of the neck for cases of myasthenia gravis].

Extended thymectomy in conjunction with a collar incision of the neck was performed thoracoscopically for a 64-year-old women with myasthenia gravis. Although this patient had Osserman type II B myasthenia gravis not associated with a thymoma, the clinical symptoms were alleviated after the surgery. Although this surgical procedure has the disadvantage such as of being time-consuming, it also has various advantages such as: 1) extended thymectomy can be performed without a midsternotomy, 2) the wound is small and not prominent, 3) surgical invasiveness is slight, and 4) postoperative pain is mild. This method was considered to be an extremely useful surgical method which should be used in future for cases of myastenia gravis not associated with a thymoma.

Endoscopy↗
PubMed1996

[A surgical treatment for congenital bile duct dilatation with intrahepatic calculi].

A total of 141 cases of congenital bile duct dilatation (excluding those with cancer) were treated at the Department of gastroenterological Surgery of Tokyo Women's Medical College in the past 27 years. The lesion was morphologically classified as Todani type I in 93 patients, type II in 1, type III in 2, type IV-A in 42, and type V or multiple dilatation of the peripheral bile ducts in 3. Cholangiectasis was accompanied by intrahepatic stones in 1 type I patient, 18 type IVA patients, and 2 type V patients. None of type II and type III patients had intrahepatic stones. Of the 21 patients with intrahepatic stones, only 2 (both type IVA) had no history of surgery. In these patients, a common bile duct stone was considered to be the cause of intrahepatic stone formation. Nineteen patients had undergone surgery, comprising cholecystectomy in 2 type V patients, bypass surgery in 5 type IVA patients, and excision of the extrahepatic bile ducts with biliary tract reconstruction in 1 type I and 11 type IVA patients. Of the 12 patients who underwent excision of the extrahepatic bile ducts with biliary tract reconstruction, intrahepatic stone formation was considered to be ascribable to stenosis at the choledocho-jejunostomy site in 3 and to insufficient excision of the extrahepatic bile ducts in 4. Therefore, when performing excision of the extrahepatic bile ducts and biliary tract reconstruction in patients with congenital cholangiectasis, we now take care to achieve thorough excision of the extrahepatic bile ducts and not leave any stenotic region in the porta hepatis. For choledocho-jejunostomy, we join the left and right hepatic ducts as necessary or incise the hepatic duct axialy so as to make the anastomotic orifice large enough. In the 5 remaining patients, intrahepatic stone formation was considered to be due to persistence of intrahepatic bile duct dilatation or stenosis, although there were no technical problem with excision of the extrahepatic ducts and biliary tract reconstruction. In 4 of the 5 patients, partial hepatectomy was performed to remove the intrahepatic stones, but new stones formed again in 2 of them. When intrahepatic bile duct dilatation or stenosis is localized at the periphery of lobule, hepatectomy is indicated. However, when intrahepatic bile duct dilatation or stenosis is extensive in both lobes, no curative technique is available and bile duct dilatation or stenosis wil persist in the liver after surgery. In such cases, the disease may become further complicated by cholangitis and intrahepatic stone formation, making it very difficult to control. Therefore, patients with extensive intrahepatic bile duct dilatation or stenosis should be monitored very carefully even after surgery.

Bile Ducts↗
PubMed1996

[Gene analysis of acid proteases].

We described gene analysis of acid proteinases, cathepsin E (CTSE), pepsinogen A (PGA), and pepsinogen C (PGC), and demonstrated the clinical significance of these genes. CTSE was highly expressed in pancreatic cancer and can be a tumor marker for pancreatic cancer. PGC gene polymorphism was associated with gastric ulcer and can be a subclinical marker of the genetic predisposition to gastric ulcer.

Amino Acid Sequence↗
PubMed1995

Antigen-driven differentiation of naive Ig-transgenic B cells in vitro.

We have established a culture system in which naive B cells bearing a transgenic, chicken OVA (cOVA)-specific Ig differentiate to plasma cells in vitro after interaction with cOVA plus cOVA-specific helper T cells. B cell-enriched populations from Ig-transgenic mice, but not from nontransgenic mice, proliferated after presenting nanomolar concentrations of cross-linked cOVA to DO11.10 (cOVA plus IAd-specific) T cells. After 6 to 9 days of culture with Ag and specific T cells, the B cells acquired a plasma cell phenotype and secreted the transgene-derived Ig at high levels. Engagement of B cell surface Ig was not essential for primary B cell differentiation. Differentiating B cells enlarged, clustered, and acquired two plasma cell markers, Syndecan and CD43. B cell CD45 isoform expression changed: the B220 isoform was lost in a T cell-dependent manner, whereas the CD45RB isoform was gained in a T-independent manner. Although unstimulated B cells survived less than 72 h in vitro, those in Ag-stimulated cultures showed reduced early death, a surge of proliferation at 3 to 5 days, and increased death late in the culture. Using a large population of naive B cells of defined antigenic specificity permits us to study a primary immune response to an Ag, rather than to less physiologic polyclonal stimuli. Because all steps of differentiation occurred in vitro, they are easily accessible for study. This coculture system provides an opportunity to observe Ag-specific T cell-B cell collaboration.

Animals↗
PubMed1995

Hemostatic, inflammatory, and fibroblast responses are blunted in mice lacking gelsolin.

Gelsolin, an 82 kDa actin-binding protein, has potent actin filament-severing activity in vitro. To investigate the in vivo function of gelsolin, transgenic gelsolin-null (Gsn-) mice were generated and found to have normal embryonic development and longevity. However, platelet shape changes are decreased in Gsn- mice, causing prolonged bleeding times. Neutrophil migration in vivo into peritoneal exudates and in vitro is delayed. Gsn- dermal fibroblasts have excessive actin stress fibers and migrate more slowly than wild-type fibroblasts, but have increased contractility in vitro. These observations establish the requirement of gelsolin for rapid motile responses in cell types involved in stress responses such as hemostasis, inflammation, and wound healing. Neither gelsolin nor other proteins with similar actin filament-severing activity are expressed in early embryonic cells, indicating that this mechanism of actin filament dynamics is not essential for motility during early embryogenesis.

Actins↗
PubMed1995

Expression of human cathepsin E in methylotrophic yeast, Pichia pastoris.

The human gastric cathepsin E (CTSE) 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 efficiently secreted into the culture medium as an active enzyme directed by its native signal sequence, whereas CTSE has been shown to be retained in mammalian tissue cells. The recombinant human CTSE was secreted as a 90-kDa molecule and then converted via an 84-kDa intermediate to an 82-kDa molecule. The 90-kDa molecule and the 82-kDa molecule were considered to be the proenzyme and the mature enzyme as dimeric forms, respectively.

Amino Acid Sequence↗
PubMed1995

Purification and characterization of recombinant human cathepsin E.

The human cathepsin E was purified from the culture supernatant of Pichia pastoris strain transformed with a human cathepsin E expression plasmid. Purification was performed by a three-step procedure, TSKgel Phenyl-5PW, Toyopearl HW55S and TSKgel DEAE-5PW column chromatographies. The purified recombinant cathepsin E had the molecular mass of around 82-kDa with the amino-terminal sequence started with Ile37 of the predicted amino acid sequence, suggesting the human cathepsin E was accumulated in the culture suparnatant as the mature dimer 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 Pichia pastoris received N-linked high-mannose type glycosylation.

Cathepsin E↗