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Biomedical subjects

T Azuma

Publications and source records attributed to T Azuma.

At least 199 records · Page 11Linked to original sources
PubMed1992

Membrane region of surface IgM is not sufficient for transducing growth inhibitory signals in an immature B cell line WEHI-231.

The murine B lymphoma line WEHI-231 is representative of immature B cells. Like normal immature B cells, WEHI-231 is susceptible to growth arrest following cross-linking of surface IgM (sIgM). Previously, we have shown using a WEHI-231 immunoglobulin (Ig) delta-transfectant that sIgD cross-linking failed to initiate growth arrest, in contrast to sIgM. In this report, we extend our research to investigate the structural requirement of Ig mu chain for regulating growth inhibition. Recombinant, chimeric Ig molecules delta/mu m and mu/delta m consisting of exons encoding extracellular delta and mu domains and membrane regions of different isotypes were constructed and introduced into WEHI-231 cells. A similar approach was used for sIgG2b-expressing transfectants. Our findings indicate that the mu m region is not sufficient for regulation of growth inhibition in WEHI-231 cells and suggest that additional extracellular region(s) of mu chain may be required for this response.

Animals↗
PubMed1992

Isolation of a gramicidin S hyperproducing strain of Bacillus brevis by use of a fluorescence activated cell sorting system.

A gramicidin S (GS) hyperproducing mutant of Bacillus brevis was isolated by using a protein-staining fluorescence dye (fluorescein isothiocyanate, FITC), and a fluorescence-activated cell sorting system (FACS). By flow cytometry (FCM) analysis after staining with FITC, higher producing cells of the wild-type had higher fluorescence signals than cells with low productivity or cells from a GS non-producing mutant. Staining with FITC did not affect the viability of cells under the conditions chosen for FCM analysis. This enabled us to recover viable cells after sorting. After wild-type cells were mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine, mutants with higher fluorescence than the parental strain were obtained by cell sorting. Among them, strain 18 was chosen as a GS hyperproducer; it produced 590 micrograms GS/ml compared to 350 micrograms/ml by the wild-type strain. This method has the advantage of being able to screen large numbers of cells in a short time. Furthermore, use of the fluorescence dye technique will expand the use of FACS to the improvement of other cultures that produce metabolites that do not have a specific fluorescence or strong enough fluorescence for normal cell sorting.

Bacillus↗
PubMed1992

Anterior sagittal anorectoplasty for rectovestibular and anovestibular fistula.

Rectovestibular (or anovestibular) fistula is the most common form of anorectal anomaly in female infants. In the surgical repair of these malformations, anal transplantation has been in widespread conventional use. Based on the idea of posterior sagittal anorectoplasty, we devised a new approach, anterior sagittal anorectoplasty, in which, in the lithotomy position, the anterior portion of sphincter muscles are cut through a median perineal skin incision and then the rectum is pulled through the center of these muscles to make its opening at the normal position. The operation has been performed in 12 patients with satisfactory results.

Anal Canal↗
PubMed1992

Kinetics of inter-heavy chain disulfide bond formation of liganded and unliganded human immunoglobulin G by radioimmunoassay.

Monoclonal antibodies (mAbs) to the hinge region of human IgG1 immunoglobulins were prepared by immunization with a proteolytic fragment of hinge segment coupled to keyhole limpet hemocyanin. A mAb, 4G3, was obtained capable of binding to intact IgG but not to partially reduced IgG. Using this mAb, inter-heavy (H) chain disulfide bond formation from partially reduced anti-tetanus antibodies (Abs) in the presence or absence of antigens (Ags) was studied by solid phase radioimmunoassay. When the Abs were partially reduced in solution and then coated to plastic plates, only 10% regeneration of inter-H chain disulfide bonds occurred after reoxidation, although 100% formation occurred in solution [Kishida et al., J. Biochem. (Tokyo) 79, 91-105 (1976)]. This difference in the extent of disulfide bond formation can be explained by the fact that there are two convertible isomers in solution, Conformer I and II, one of which (Conformer I) can form disulfide bonds but is present as a minor component. Since the motion of IgG molecules on plates is restricted by hydrophobic interactions, the two conformers are not convertible as in solution. Therefore only Conformer I which existed before coating formed inter-H chain disulfide bonds. Similar kinetic measurements were performed using plates coated with tetanus toxoid. Abs, partially reduced in solution and then allowed to react with Ags on the plate were able to completely regenerate their inter-H chain disulfide bonds, although the rate of reaction was slow. These results can also be explained by the fact that the two isomers are convertible since Ag-Ab complexes are dissociable. Ag-binding therefore did not significantly perturb conformation of the hinge segments. In addition, no difference between liganded and unliganded Abs was observed in the binding of anti-hinge mAbs. These results imply little or no contribution of the hinge region to transmission of the signal produced by Ag-binding to Fc.

Amino Acid Sequence↗
PubMed1992

Detection of a polymorphism within the pepsinogen C gene with PCR: construction of a linkage map around PGC from 6p11-6p21.3.

An insertion/deletion polymorphism between exons 7 and 8 of the pepsinogen C gene (PGC), previously detectable with Southern analysis, was formatted for detection with PCR. Alleles were rapidly typed by UV irradiation of ethidium bromide-stained agarose gels. Whereas Southern analysis revealed two alleles, the smaller fragments generated with PCR allowed the resolution of three alleles that were previously scored as a single allele and increased the heterozygosity of the system from 0.20 to 0.53. After a set of reference families was genotyped with the PCR-based polymorphism, a linkage map around the PGC gene on chromosome 6 was constructed. This included the HLA cluster and the highly informative D6S223 locus. PGC lies 22 cM proximal to HLA-DPB and between D6S5 and D6S4 at distances of 4.5 and 13.1 cM, respectively.

Base Sequence↗
PubMed1992

In vitro anti-tumor activity of anti-c-erbB-2 x anti-CD3 epsilon bifunctional monoclonal antibody.

With the aim of developing an effective cancer immunotherapy for common epithelial cancer, a new class of bifunctional antibody (BFA) was developed; one arm of this BFA recognized c-erbB-2 gene product, and the other arm recognized CD3 epsilon, a T-cell specific surface antigen. Application of this BFA with human peripheral blood lymphocytes exhibited specific anti-tumor activity in vitro on a breast tumor cell line, ZR-75-1, which expressed abundant c-erbB-2 gene product on its cell surface. These results indicate that BFA recognizing an oncogene product on cell surface is a potential new agent for cancer immunotherapy.

Antibodies, Monoclonal↗
PubMed1992

Serotype 2 reoviruses from the feces of cats with and without diarrhea.

During a virus survey carried out in the period 1989-90 with 148 fecal samples collected from cats in Japan, three reovirus strains were isolated in feline cell cultures. Two strains (Nos. 114 and 140) were from 48 diarrheal fecal samples and another strain (No. 32/41) was from 100 normal fecal samples. The strains grew in feline and simian cell cultures with producing typical intracytoplasmic inclusion bodies in which virus particles were densely packed. All strains, especially Nos. 32/41 and 140 strains, showed trypsin-dependent growth in vitro. Their ultrastructural and genomic properties were characteristic of genus reovirus in the Reoviridae. All strains agglutinated erythrocytes of human type O but not of bovine. Although they were identified as serotype 2 by hemagglutination-inhibition test with the hyperimmune sera against human reovirus prototype strains, No. 114 strain was typical and the other two strains were atypical serotype 2 reoviruses. Furthermore, from the reason that Nos. 32/41 and 140 strains possessed some common properties though derived from cats in distant locations, they were considered to be reoviruses having been maintained in the cat population. Seroepizootiologic survey revealed that the prevalence of serotype 3 infection was most widespread and serotype 2 was least among three serotypes of reovirus in a cat population.

Animals↗
PubMed1992

[Microalbumin excretion in the group of patients with asymptomatic hematuria].

Urine albumin was determined in patients with chronic glomerular injuries with normal renal function, who had shown positive test of microhematuria but negative test of proteinuria at any time of our renal clinic. The subjects were divided into 4 groups: (1) IgA nephropathy (IgAN); 13, (2) asymptomatic hematuria (AS); 18, (3) nephrotic syndrome in complete remission (CR); 21 and (4) age matched normal subjects; 44. Urine albumin concentration was measured with radioimmunoassay in the ambulatory urine, and, in some cases, in the urine obtained after supine position for 30 minutes to demonstrate the effect of ambulatory physical movement on albumin excretion. Also urine alanine aminopeptidase (AAP) and N-acetyl-beta-D-glucosaminidase (NAG) were estimated by monitoring the absorbance of products released by the enzyme, as the indices of tubular function. The results indicated that urine albumin were 8.4 +/- 7.3 mg/g Cr (Mean +/- SD) in normal subjects, and 8.8 +/- 8.9 mg/g Cr in CR (vs. controls: N.S.), 18.9 +/- 14.5 mg/g Cr in AS (P = 0.0071), and 22.2 +/- 14.9 mg/g Cr in IgAN (P = 0.0063). The albumin excretion had no relation with the grade of microhematuria and also with the ambulatory physical movement. Moreover, AAP and NAG excretion in each group had shown no significant alterations. These results indicate that urine albumin increases in IgAN and AS with normal renal function and with microhematuria alone, but not in CR. Urine albumin is probably glomerular origin, since no abnormality is found in the tubular functions.

Acetylglucosaminidase↗
PubMed1992

A basic study on removal of nutrient salts in wastewater using plants (removal by mung beans; Phaseolus radiatus L).

Many studies have reported on the removal of pollutants from wastewater using aquatic plants. The water hyacinth has been the most widely used and its system is the most well established. This system however, has a few problems in practical use. The purpose of this study is to obtain basic information on a new system that can substitute for a conventional system or be used as a secondary system to assist the conventional one. We first envisioned a model of this new system and then conducted a preliminary experiment using a small experimental unit to simulate the new system. The experiment showed that mung beans were a suitable plant for our study. Their removal rate of pollutants was the highest before they developed leaves and started photosynthesis. We found that nutrients were expelled outside the plant root when nutrient concentration inside the plant tissue became too high.

Absorption↗
PubMed1992

A spigelian hernia in an infant.

The case of a two-month old Japanese girl with a left side Spigelian hernia that developed during the course of recovery from the surgical treatment of a meningomyelocele and ventriculo-peritoneal shunting (V-P shunting) is reported on. At this time, to our knowledge, 20 cases involving infants and children have been reported on in world-wide medical literature. Of these cases, 4 cases were caused by trauma, 1 by abdominal surgery, and the others had no evident causes. Our patient had a meningomyelocele, and underwent a V-P shunting. However, a cause and effect relationship between the Spigelian hernia and the treatment of the meningomyelocele followed by V-P shunting is inconceivable. We doubt any relationship between the preceding neurosurgery and the development of the hernia. This is the first case of infantile Spigelian hernia reported on in Japan.

Female↗
PubMed1992

[Epidemiology, prognosis and causes of death in rheumatoid arthritis].

The prevalence of RA in Japan has been reported to be approximately 0.3% of general population and the ratio of male to female patients is 1 to 4. The course of RA is classified into 3 types, those are monocyclic, polycyclic and progressive. The polycyclic and progressive courses of RA would have been ameliorated by the recent progress of medical and surgical treatment and an increased number of patients in monocyclic course would be expected. The mortality rate among RA patients is higher than that of population control. There are causes of death directly related to rheumatoid process itself and resulted from drug treatment. The former includes secondary amyloidosis and basilar impression and the latter includes infection, renal failure and GI bleeding.

Adolescent↗