Biomedical subjects

Y Hirai

Publications and source records attributed to Y Hirai.

At least 19 recordsLinked to original sources

PubMed1992

Evidence for in vivo clonal proliferation of unique population of blood CD4-/CD8- T cells bearing T-cell receptor alpha and beta chains in two normal men.

Rare T lymphocytes bearing CD3 surface antigen and T-cell receptor (TCR) alpha and beta chains, but lacking both CD4 and CD8 antigens, viz, TCR alpha beta+CD4-8- cells, appear at a frequency of 0.1% to 2% in peripheral blood TCR alpha beta+ cells of normal donors. Here we report two unusual cases, found among 100 healthy individuals studied, who showed an abnormally elevated frequency of these T cells, ie, 5% to 10% and 14% to 19%. Southern blot analyses of the TCR alpha beta+CD4-8- clones all showed the identical rearrangement patterns for each individual, demonstrating that these are derivatives of a single T cell. The same rearrangement patterns were also observed for the freshly isolated lymphocytes of TCR alpha beta+CD4-CD8- fraction, which excludes the possible bias in the processes of in vitro cloning. These TCR alpha beta+CD4-8- T cells were found to express other mature T-cell markers such as CD2, CD3, and CD5 antigens, as well as natural killer (NK) cell markers (CD11b, CD16, CD56, and CD57 antigens) for both individuals. Further, although lectin-dependent or redirected antibody-dependent cell-mediated cytotoxicities were observed for both freshly sorted lymphocytes of TCR alpha beta+CD4-8- fraction and in vitro established clones, NK-like activity was not detected.

Antigens, CD↗

PubMed1992

Epimorphin: a mesenchymal protein essential for epithelial morphogenesis.

A novel 150 kd protein expressed on the surface of mesenchymal cells of mouse embryonic tissues was identified. A monoclonal antibody to this molecule inhibited various processes of epithelial morphogenesis, such as hair follicle growth and lung epithelial tubular formation, in organ cultures of these tissues. Sequence analysis of cDNA encoding this protein revealed that it had 289 amino acids with a hydrophobic stretch at the C-terminus. NIH 3T3 cells transfected with the cDNA of this protein expressed the exogenous 150 kd protein on their surface. When lung epithelial cells were cocultured with these transfected cells, they showed normal tubular morphogenesis, but not with untransfected NIH 3T3 cells. These results indicate that this protein, termed epimorphin, plays a central role in epithelial-mesenchymal interactions.

Amino Acid Sequence↗

PubMed1992

A simple and rapid method for HLA-DQA1 genotyping by polymerase chain reaction-single strand conformation polymorphism and restriction enzyme cleavage analysis.

A simple and rapid method for identification of alleles at the human leucocyte antigen (HLA)-DQA1 locus is described. The polymorphic second exon of the HLA-DQA1 locus was amplified by the polymerase chain reaction (PCR) method. The amplified DNA was analyzed by single-strand conformation polymorphism (SSCP) and restriction enzyme cleavage assay. Using this method, the eight known DQA1 alleles could be distinguished from each other. This paper suggests that the method can be used for quick genotyping of DQA1 alleles, but detecting point mutations at various positions in a fragment as well as new HLA-DQA1 genotypes should also be possible.

Alleles↗

PubMed1992

Functional implications of interleukin-1 beta based on the three-dimensional structure.

The molecular structure of interleukin-1 beta, a hormone-like cytokine with roles in several disease processes, has been determined at 2.0 A resolution and refined to a crystallographic R-factor of 0.19. The framework of this molecule consists of 12 antiparallel beta-strands exhibiting pseudo-3-fold symmetry. Six of the strands make up a beta-barrel with polar residues concentrated at either end. Analysis of the three-dimensional structure, together with results from site-directed mutagenesis and biochemical and immunological studies, suggest that the core of the beta-barrel plays an important functional role. A large patch of charged residues on one end of the barrel is proposed as the binding surface with which IL-1 interacts with its receptor.

Humans↗

PubMed1992

Proteolytic digestion of alpha-lactalbumin: physiological implications.

The kinetics of the partial digestion of bovine alpha-lactalbumin (alpha-LA) by trypsin, alpha-chymotrypsin, and pepsin was monitored by lactose synthase activity, HPLC, and difference spectrophotometry. The relative stabilities of the various metal-bound states of alpha-LA to trypsin and chymotrypsin at 37 and 5 degrees C decrease in the following order: Ca(II)-alpha-LA greater than Zn(II), Ca(II)-alpha-LA greater than apo-alpha-LA. The HPLC digestion patterns of Ca(II)-alpha-LA and Zn(II), Ca(II)-alpha-LA at 5 and 37 degrees C were similar, while the corresponding digestion patterns for apo-alpha-LA were quite different, reflecting the existence of the thermally induced denaturation states of apo-alpha-LA within this temperature region. Occupation of the first Zn(II)-binding site in Ca(II)-loaded alpha-LA slightly alters the HPLC digestion patterns at both temperatures and accelerates the digestion at 37 degrees C due to Zn(II)-induced shift of the thermal transition of alpha-LA, exposing some portion of thermally denatured protein. The results suggest that the binding of Zn(II) to the first Zn(II)- (or Cu(II)-specific site does not cause any drastic changes in the overall structure of alpha-LA. The acidic form of alpha-LA (at pH 2.2 and 37 degrees C) was digested by pepsin at rates similar to that for the apo- or Cu(II), Ca(II)-loaded forms by trypsin or alpha-chymotrypsin at neutral pH. Complexation of alpha-LA with bis-ANS affords protection against pepsin cleavage. It is suggested that the protective effects of similar small lipophilic compounds to alpha-LA may have physiological significance (e.g., for nutritional transport).

Animals↗

PubMed1992

Frequency of mutant T lymphocytes defective in the expression of the T-cell antigen receptor gene among radiation-exposed people.

The frequency of mutant T lymphocytes defective in T-cell receptor gene (alpha or beta) expression was measured using the 2-color flow cytometric technique. Results for a total of 203 atomic bomb survivors, 78 of whom were proximally exposed (DS86 doses of greater than or equal to 1.5 Gy) and 125 of whom were distally exposed (DS86 dose of less than 0.005 Gy), showed that the mutant frequency was significantly higher in males than in females. No significant dose effects were observed. In contrast, a significant increase of mutant frequency was observed for 6 patients treated with Thorotrast, a contrast medium containing thorium-232 formerly used for radioligands. In addition, thyroid disease patients treated with 131I showed a dose-related increase of mutant frequency. It was suggested that the present T-cell receptor mutation assay has a unique characteristic as a biological dosimeter for measurement of recent exposures to genotoxic agents.

Adult↗

PubMed1992

Development of a flow-cytometric HLA-A locus mutation assay for human peripheral blood lymphocytes.

A flow-cytometric technique was developed to measure the frequency of variant lymphocytes lacking expression of HLA-A2 or A24 allele products among donors heterozygous for HLA-A2 or A24. It was found that the variant frequency of lymphocytes in peripheral blood was of the order of 10(-4) and increased with donor age. Molecular analyses of mutant clones revealed that about one-third were derived from somatic recombinations and that the remaining two-thirds did not show any alterations after Southern blotting analysis. In contrast, mutants obtained after in vitro X-ray mutagenesis study were found to be mostly derived from large chromosomal deletions. A small-scale study on atomic bomb survivors did not show a significant dose effect.

Adult↗

PubMed1992

Soybean protein isolate and soybean lectin inhibit iron absorption in rats.

Inhibitory effects of soybean protein isolate (SPI) and soybean lectin on the intestinal absorption of nonheme iron were investigated by in vivo studies in rats. Rats fed the SPI-based diet absorbed significantly less iron than did control rats fed the casein-based diet. Supplementing the SPI diets with 8% D-galactose significantly increased the incorporation of iron into liver ferritin, although D-galactose did not significantly increase iron absorption. Heat treatment of SPI significantly increased iron absorption. Ascorbate did not enhance iron absorption in rats fed the SPI-based diet. The presence of lectin in an aqueous extract of SPI was suggested by hemagglutination activity as well as by immunoreactivity with soybean lectin antibody. Soybean lectin introduced into ligated segments of the upper small intestine of rats inhibited ferrous iron absorption. This inhibitory effect, especially in the mucosal uptake, was significantly improved by addition of N-acetyl-D-galactosamine to soybean lectin. Soybean lectin had no effect on ferric iron absorption. Our results suggest that a portion of the reduction in iron absorption in rats fed SPI may be due to lectins.

Animals↗

PubMed1992

A latex agglutination test for the detection of Mycoplasma pneumoniae in respiratory exudates: a comparative study with a commercially available DNA-probe test.

We prepared polyclonal antibody specific to Mycoplasma pneumoniae. Using this antibody, we developed a latex agglutination test (LAT) for detecting the organism in respiratory exudates as rapid diagnosis of M. pneumoniae infection. Further, LAT was compared with DNA-probe test (DP) which was the only commercially available test for the rapid detection of the organism. In LAT, both M. pneumoniae and M. genitalium give positive agglutination, but the titer of M. genitalium was significantly lower than that of M. pneumoniae. The detection limit of LAT was 2 x 10(5) CFU/ml and that of DP was 5 x 10(4) CFU/ml in vitro. It was considered that target molecules in LAT were accumulated in the pharyngeal portion of the patients, because of their long half-life at 37 C. However, ribosomal RNA which was target molecule in DP was destroyed at 37 C much sooner, and the accumulation could not be expected. Actually, positive rate in LAT was higher than that in DP among clinical specimens in which M. pneumoniae was detected by culture method. The procedure of LAT is much easier and more rapid than that of DP in which radioactive isotope is required. LAT could be the choice of test for rapid diagnosis of M. pneumoniae infection.

Antigens, Bacterial↗

PubMed1992

Studies on osmotic stability of liposomes prepared with bacterial membrane lipids by carboxyfluorescein release.

The authors measured the osmotic stability of liposomes prepared with membrane lipids of bacteria, using the osmotic-shock release of entrapped carboxyfluorescein as an indicator. The sub-second physical changes of liposomes suspended in a solution of low osmotic pressure were examined by stopped flow spectrophotometry. The entrapped carboxyfluorescein was released when the liposomes burst on inflow of excess water. Liposomes prepared with the lipids of a stable Staphylococcus aureus L-form strain were more resistant to low osmotic pressure than those prepared from the wild strain of S. aureus, and liposomes prepared from Mycoplasma orale were even more resistant. Cardiolipin enhanced the lipid membrane stability in S. aureus and cholesterol in M. orale. The stability of lipid membranes to low osmotic pressure could be precisely determined by the present method.

Cardiolipins↗

PubMed1992

Induction of cytokines in human peripheral blood mononuclear cells by mycoplasmas.

Various species of mycoplasmas were tested for their ability to induce cytokine production in human peripheral blood mononuclear cells (PBMC). Human PBMC were incubated with Mycoplasma pneumoniae, M. hyorhinis, M. arginini, M. salivarium, M. orale, M. gallisepticum or A. laidlawii for 48 hr, and the activities of interleukin-1 beta (IL-1 beta), IL-2, IL-4, IL-6, tumor necrosis factor-alpha (TNF-alpha) and interferon (IFN) in the supernatants were determined by ELISA or bioassay. All mycoplasma species induced IL-1 beta, IL-6 and TNF-alpha, although IL-2 was induced only by M. pneumoniae. IFN was induced by 5 of the 7 species, and the IFN produced was antigenically confirmed to be mainly IFN-alpha. On the other hand, mycoplasma-stimulated cultures did not contain detectable amounts of IFN-beta and IL-4 activities. Furthermore, the cytokines were induced by mycoplasmal contaminating cells in human PBMC as well as by mycoplasma alone. These results suggest that many kinds of cytokines induced by mycoplasma contamination in cell culture affect immunological experiments in vitro.

Biological Assay↗

PubMed1992

Changes in bone mineral density and fracture prevalence in Japanese women after oophorectomy.

The bone changes after gynecological surgery during the early phase of recovery were examined. The subjects were randomly selected from women who had undergone bilateral oopho-hysterectomies (OOX, n = 98, 46.0 +/- 5.0 year-old) or hysterectomies (HX, n = 75, 43.6 +/- 4.6 year-old) within 4 years prior to entering the study. The ovarian functions in the HX group were presumed to be intact following the hysterectomies, judging from the cytological evaluation of the vaginal pap smears. The bone morphological changes in both groups were examined to measure the cortical thickness of the metacarpal bone (MCI) on hands X-ray film using microdensitometry, and the posterior/anterior height ratios (P/A ratio) of the entire vertebral bodies, on vertebral X-ray films using a digitizer. The changes in bone mineral densities in both groups were measured by dual energy X-ray absorptiometry at lumbar vertebrae (L2-4 BMD) and by microdensitometry at the metacarpal cortical bone; the bone densities of metacarpal bone were referenced by the density of aluminum step wedge on the same X-ray films. The prevalence of vertebral body fractures (P/A ratio greater than 1.4) in the OOX group (5.1%) was 3.9 times higher than that in the HX group (1.3%). There was a significant decrease in MCI in the OOX group compared with the HX group (p less than 0.01). L2-4 BMD in the OOX and HX group were 1.07 +/- 0.15 and 1.16 +/- 0.13 g/cm2, respectively (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

The immunohistochemical localization of new membrane-associated placental tissue proteins (MP2 A, B, C, D, and E) in human and cynomolgus monkey placentae.

New membrane-associated placental tissue proteins (MP2 A, B, C, D, and E) were investigated by avidin-biotin immunoperoxidase technique in the human and cynomolgus monkey placentae, decidua and umbilical cords. In human early placentae, MP2 A, B, C, and E were localized mainly in the membrane of villous syncytiotrophoblasts and cytotrophoblasts. Histiocytes in the villous stroma were positive for MP2 A, B, D, and E. In human term placentae, obvious positive staining for MP2 A, B, C, and E was observed in the membrane of villous syncytiotrophoblasts, in the amniotic epithelium, and in the umbilical cord sheath. Histiocytes in the villous stroma were positive for MP2 A, B, C, E, and especially for MP2 D. Importantly, MP2 A, C, and E were positive in polymorphonuclear neutrophils, since most of these common antigens are also carcinoma-associated, suggesting clinical usage of MP2 proteins as a new tumor marker. In the cynomolgus monkey placentae, similar immuno-staining results were obtained. The monkey can thus serve as a experimental model for the investigation of the placental proteins.

Amnion↗

PubMed1992

Preliminary experience with gadolinium-enhanced dynamic MR imaging for uterine neoplasms.

Usefulness of gadopentetate dimeglumine in magnetic resonance (MR) imaging of uterine neoplasms was evaluated in 53 patients with endometrial carcinoma and 15 patients with cervical carcinoma. T1- and T2-weighted MR images were obtained before the contrast material was administered. After a bolus injection of gadopentetate dimeglumine, dynamic MR images were acquired, followed by static T1-weighted images. Gadolinium-enhanced MR images revealed relatively small endometrial carcinomas in the uterine cavity as high signal intensity in four cases and invasion of the myometrium as low signal intensity in 20 cases. In eight cases, endometrial tumors showed irregular, early enhancement compared with that of the myometrium on dynamic images; these cases were associated with poor prognosis. Tumor extension into the lower part of the uterus, parametrium, and paracervical fat was well seen on enhanced images in cases of cervical carcinoma. The authors believe that gadolinium-enhanced MR imaging will prove helpful in the staging of uterine neoplasms.

Adenocarcinoma↗

PubMed1992

[Effects of bufadienolides and some kinds of cardiotonics on guinea pig hearts].

Effects of bufadienolides such as bufalin (BF) and cinobufagin (CB), the main components of Senso (Ch'an Su), on myocardial Na+,K(+)-ATPase activity, the cardiotonic activity in vivo and the action potential of isolated guinea pig papillary muscle cells were compared with those of other cardiotonic drugs. 1) The rank order of potency for inhibition of myocardial Na+,K(+)-ATPase activity was BF greater than digoxin (DG) greater than digitoxin (DT) greater than telocinobufagin greater than gamabufotalin greater than cinobufotalin greater than CB greater than g-strophanthin (GS) greater than digitoxigenin (DTG) greater than resibufogenin (RB) when compared at the 50% inhibitory concentration. 2) In isolated papillary muscle cells, CB shortened the action potential duration (APD) dose-dependently. The order of potency for shortening of APD was GS greater than CB greater than DTG much greater than DT. 3) In open-chest guinea pigs, intraduodenal administration of BF or CB increased the myocardial contractile force (MCF), but did not affect the heart rate. The order of potency for increase in MCF was as follows: methyldigoxin, proscillaridin greater than BF greater than CB greater than DG greater than Senso much greater than DT, DTG, RB. These results indicate that CB has a shortening effect on APD and an inhibitory effect on Na+,K(+)-ATPase activity along with its cardiotonic effect, like GS.

Action Potentials↗

PubMed1992

[Pharmacological effects of Gosha-jinki-gan-ryo extract: effects on experimental diabetes].

Pharmacological effects of Gosha-jinki-gan-ryo extract (KJE) on experimental diabetes induced by cyproheptadine (CPH), aldose reductase activity, and experimental peripheral neuropathy were studied. The effects of KJE were compared with those of Hachimi-jio-gan-ryo extract (HJE). KJE at 417 mg/kg/day (5 times the daily dose in humans) and HJE at 367 mg/kg/day (5 times the daily dose in humans) significantly inhibited the decrease in glucose tolerance by CPH. KJE and HJE inhibited aldose reductase activity, when DL-glyceraldehyde was used as substrate, with IC50 values of 2.68 x 10(-5) g/ml and 4.45 x 10(-5) g/ml, respectively and when D-glucose was used as substrate, with IC50 values of 1.04 x 10(-4) g/ml and 1.55 x 10(-4) g/ml, respectively. KJE at 209 mg/kg/day (2.5 times the daily dose in humans) and HJE at 367 mg/kg/day significantly reduced peripheral neuropathy induced by crushing the sciatic nerve in rats. The potency of these effects of KJE was stronger than that of HJE, when a comparison was made on the basis of the daily dose.

Aldehyde Reductase↗

PubMed1992

Isolation of substance P binding protein from rat brain.

Substance P (SP) binding protein of rat brain was solubilized by digitonin. The solubilized proteins were then purified by sequential gel filtration, concanavalin A lectin Sepharose, and SP-affinity chromatography. The calculated molecular weight of this purified SP binding protein was 76-74 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The rabbits were immunized with the purified protein and resulting polyclonal anti-sera were tested. The immune serum significantly inhibited [3H]SP binding to the 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate solubilized membrane fractions from rat brain, whereas pre-bleed antiserum failed to inhibit the binding. This polyclonal antibody also inhibited the activity of 45Ca influx into astroglioma cells stimulated by SP, but does not inhibit that stimulated by histamine. Furthermore, this polyclonal antibody recognized the 76-74 kDa band as assessed by Western blotting. These data strongly suggest that this polyclonal antibody could recognize a part of the natural SP receptor site.

Animals↗

PubMed1992

Measurement of urinary delta-aminolevulinic acid (ALA) by fluorometric HPLC and colorimetric methods.

We devised a fluorometric HPLC method for determining delta-aminolevulinic acid (ALA) in the urine of lead-exposed workers. With this fluorometric HPLC method and the conventional colorimetric method, the concentrations of urinary ALA in 84 lead workers were determined and compared. In the measurement of urinary ALA at lower levels (< or = 5 mg/1), the value of urinary ALA obtained by the fluorometric HPLC method was much lower than that obtained by the conventional colorimetric method, indicating that the colorimetric method also measures urinary ALA-like compounds such as aminoacetone. On the other hand, the measurement of urinary ALA at higher levels (> 5 mg/1) demonstrated that the ALA value obtained by the fluorometric HPLC method corresponded well with that of the conventional colorimetric method. A correlation coefficient between the fluorometric HPLC method and the colorimetric method was 0.856 for 60 urine samples with ALA < or = 5 mg/1, and 0.996 for 24 urine samples with ALA > 5 mg/1.

Aminolevulinic Acid↗