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Biomedical subjects

M Homma

Publications and source records attributed to M Homma.

At least 19 recordsLinked to original sources
PubMed1992

Characterization of autoantibodies that recognize U4/U6 small ribonucleoprotein particles in serum from a patient with primary Sjögren's syndrome.

We identified autoantibodies that recognize the U4/U6 snRNPs in a serum from a 63-year-old Japanese patient (TT) with primary Sjögren's syndrome. This patient's serum immunoprecipitated U4 and U6 sn-RNAs exclusively from 32P-labeled HeLa cell extracts and a newly identified 120-kDa protein along with the Sm core proteins (B'/B, D, E, F, and G) from [35S] methionine-labeled HeLa cell extracts. Immunoblotting demonstrated that only the 120-kDa protein was recognized by this unique serum. In glycerol density gradient centrifugation, the 120-kDa protein reactive with TT serum cosedimented with U4 and U6 snRNAs, suggesting that the 120-kDa protein is a unique component of the U4/U6 snRNP particle. In the same study, the U4/U6 snRNP precipitated by TT serum sedimented only in the lower density, whereas anti-Sm antibodies precipitated U4/U6 snRNAs in a broad range of the gradient. This result suggests the presence of at least two molecular forms of the U4/U6 snRNP particles; larger particles, probably the U4/U5/U6 snRNP complex, and free particles. Thus, the U4/U6 snRNP recognized by TT serum includes the U4 and U6 snRNAs, with Sm core proteins, and the novel 120-kDa protein, and appears to be a free particle not associated with larger complexes.

Autoantibodies↗
PubMed1992

Genomic structure of the ME491/CD63 antigen gene and functional analysis of the 5'-flanking regulatory sequences.

Genomic structure of the ME491/CD63 antigen gene and promoter activity of the 5'-flanking regulatory sequences were studied. The antigen gene consists of eight exons that span 4 kilobase-pairs. Primer extension analysis with RNA from cultured human cells identified three major transcription initiation sites. The 5'-flanking region of exon 1 has features characteristic to promoters of many house-keeping genes and growth-regulating genes. The region is highly GC rich and contains potential binding sites for transcription factors such as Sp1 and ETF, but not a TATA box. The 5'-flanking sequence exerted strong promoter activity when linked to a reporter gene. Deletion mutant analysis of the 5'-flanking sequence has strongly suggested that a potential binding site for AP-1 plays an important role in positively regulating the gene expression.

Amino Acid Sequence↗
PubMed1992

Autoantibodies to small nuclear and cytoplasmic ribonucleoproteins in Japanese patients with inflammatory muscle disease.

OBJECTIVE: To elucidate the profile and clinical significance of autoantibodies to small nuclear and small cytoplasmic ribonucleoproteins in Japanese patients with polymyositis and dermatomyositis (PM/DM). METHODS: Radioimmunoprecipitation assays were performed with sera from 91 patients with various inflammatory muscle diseases and from 254 control patients with other rheumatic diseases. Patients with PM/DM were categorized according to autoantibody specificities, and clinical comparisons were made. RESULTS: Antibodies to aminoacyl transfer RNA (tRNA) synthetases and the signal recognition particle (SRP) were found to be specific for PM/DM: PM/DM patients with antibodies to 3 aminoacyl-tRNA synthetases (histidyl, threonyl, and glycyl) appeared to form a distinct clinical subset, associated with chronic interstitial lung disease, polyarthritis, and myositis, while 3 patients with antibodies that bound the SRP had severe myositis that was resistant to corticosteroid therapy. In general, the frequency and clinical correlations of anti-aminoacyl-tRNA synthetase antibodies in Japanese patients were similar to those in North American populations. In contrast, among this Japanese cohort, the occurrence of anti-PM/Scl appeared to be reduced in frequency, whereas anti-Ku and anti-U2 RNP antibodies were accentuated in patients with overlap syndromes. CONCLUSION: We conclude that racial groups differ somewhat in their characteristic autoimmune responses to individual autoantigens. These differences could reflect variation in immunogenetic background or different etiologic mechanisms which might occur at different geographic locations.

Asian People↗
PubMed1992

Autoantigenic epitopes of the B polypeptide of Sm small nuclear RNP particles. Identification of regions accessible only within the U1 small nuclear RNP.

OBJECTIVE: To analyze the autoantigenic epitopes of the Sm B polypeptide of the U1 small nuclear RNP (snRNP) using complementary DNA (cDNA) clones. METHODS: Expression of Sm B fusion proteins in lambda phage vectors, immunoblots, immunoprecipitations, and affinity purification of antibodies. RESULTS: Immunoblots using antibodies affinity-purified from B fusion proteins demonstrated that there were cross-reactive epitopes between the B'/B and A polypeptides of the U1 snRNP. Immunoprecipitation assays suggested that there were at least 3 different autoantigenic epitopes on the B polypeptide that could be classified into 2 general groups based upon autoantibody reactivity. The first group of autoantibodies, which bound 2 separate autoantigenic epitopes (BU1-1, BU1-2), participated in immunoprecipitation of the U1 snRNP alone. The second group, which bound the third type of autoantigenic epitope (BSm-1), immunoprecipitated all the abundant Sm snRNPs. CONCLUSION: There is at least 1 region on the B proteins that is accessible to antibodies only within the structure of the U1 snRNP, as well as a region that is accessible on all Sm snRNPs. These data support the notion that the native U1 RNP, perhaps containing B proteins in a different conformation than those found on other Sm snRNPs, may drive the humoral immune response in systemic lupus erythematosus.

Amino Acid Sequence↗
PubMed1992

Correlation between the virulence of Francisella tularensis in experimental mice and its acriflavine reaction.

Correlation between the virulence of Francisella tularensis in experimental mice and its acriflavine reaction was studied. The cultures derived from all four strains (Ebina, CMB2, Schu, and N9) that had long been subcultured on agar media yielded two types of colonies, i.e., acriflavine reaction-positive (acf+) and acriflavine reaction-negative (acf-) colonies. All acf+ colonies, regardless of their parent strains, were shown to be low virulent in mice. Acf- colonies were shown to be either high (Ebina, CMB2) or low (Schu, N9) virulent. The low-virulent acf- colonies gained virulence during several passages in mice, whereas the acf+ colonies remained low virulent even after the animal passages.

Acriflavine↗
PubMed1992

A strategy for discovering biologically active compounds with high probability in traditional Chinese herb remedies: an application of saiboku-to in bronchial asthma.

A novel strategy for discovering biologically active components in traditional Chinese herb remedies was performed from a pharmacokinetic view. The hypothesis was that the active compounds should appear in blood and urine with appropriate blood concentrations and urinary excretion rates after the administration of herbal-extract mixtures. In this research, we applied our procedures to Saiboku-To, one of the most popular Chinese herbal medicines in Japan. Consisting of 10 different plant extracts, it is used for the treatment of bronchial asthma. The analytical method adopted was a rapid-flow fractionation (RFF) for extraction-fractionation of lipophilic components in urine followed by silica-gel high-performance liquid chromatography (HPLC) equipped with a multichannel ultraviolet (uv) absorption detector. beta-D-Glucuronidase-treated urine samples collected before and after the administration of Saiboku-To to healthy and asthmatic subjects were treated with the RFF apparatus to afford three pH-dependent fractions: strongly acidic (S), weakly acidic (W), and neutral (N). HPLC of these fractions, monitored by the multichannel uv detector, showed three new peaks in the postadministrative urine: one in the N fraction, two in the W fraction, and none in the S fraction. A compound in the N fraction was identified with authentic magnolol, a major component in Magnolia officinalis. Two compounds in the W fraction were identified by comparison with authentic samples as 8,9-dihydroxydihydromagnolol and liquiritigenin, metabolites previously isolated from M. officinalis and Glycyrrhiza glabra, respectively.

Administration, Oral↗
PubMed1992

Mutation of the HANA protein of Sendai virus by passage in eggs.

A study was made to elucidate the effect of host cells on the HANA protein of Sendai virus. Two strains of Sendai virus were isolated from an epidemic in an animal laboratory by inoculating the lung homogenate of a moribund mouse either into LLC-MK2 cells (Oh-L) or into the allantoic cavity of embryonated eggs (Oh-E). Oh-E agglutinated chicken red blood cells at 37 degrees (HA37+), while Oh-L did not (HA37-). When Oh-L was passaged in eggs, conversion of the HA37- virus to the HA37+ virus readily occurred. A single point mutation was recognized on the HANA protein of the HA37+ virus either at position 525 (Gln----Arg) or at position 198 (Leu----Phe). Hl test with monoclonal antibody revealed conformational changes around the receptor binding site. Neuraminidase activity was also affected by these mutations. The changes in these biological activities of the HANA protein seemed to allow the HA37+ virus to replicate in eggs. On the contrary, the HA37+ virus replicates as efficiently as the HA37- virus in LLC-MK2 cells and no reversion to the HA37- virus was observed. The overall results indicate that the passage of Sendai virus in eggs resulted in selection of viruses possessing a specific mutation on the HANA protein. The pneumopathogenicity in mice was not significantly different between the HA37- virus and the HA37+ virus, suggesting the existence of genes other than the HANA gene that determine mouse pathogenicity.

Amino Acids↗
PubMed1992

Evaluation of a protease activation mutant of Sendai virus as a potent live vaccine.

A protease activation mutant of Sendai virus, TR-5, was investigated as a candidate for a live vaccine. Vaccination with TR-5 which had been activated by chymotrypsin beforehand (active TR-5) elicited protective immunity against otherwise lethal challenge infection with wild-type Sendai virus in DBA/2, C3H and ICR strains of mice. Less of the active TR-5 was required to confer protection on mice compared with an ordinary ether-inactivated Sendai virus vaccine (split vaccine). The protective immunity elicited by TR-5 lasted longer and the booster effect was more prominent compared to the split vaccine. No seroconversion was observed with contact mice when housed in a cage with mice vaccinated with the active TR-5. The overall results show that the active TR-5 is an effective and safe live vaccine of Sendai virus in mice.

Administration, Inhalation↗
PubMed1992

Immunoblotting analysis of sera from patients with candidal vaginitis and healthy females.

Antigenic components of Candida albicans were extracted from whole cells with a buffer containing SDS and 2-mercaptoethanol, and separated by SDS-polyacrylamide gel electrophoresis. The components reactive with IgG, IgA, IgM and IgE antibodies in sera from patients with (14 subjects) and without (15 subjects) C. albicans in the vagina, and from healthy females (34 subjects), were investigated by immunoblotting using immunoglobulin class-specific antibodies. Many components reacted with IgG and IgA in all sera tested; the major antigens that reacted strongly with the sera were 67, 62, 29 and 25 kDa components. Several components were observed which reacted with IgM in 63% of the sera; the 67, 62 and 25 kDa components that reacted with IgG and IgA also reacted with IgM. No components reacting with IgE were detected in any of the sera. No striking differences in antibody binding profiles to whole cell antigens were detected among the C. albicans positive and negative patients or the healthy subjects. On the other hand, IgG against extracellular proteinase was more frequently detected in the C. albicans positive patients than in the C. albicans negative group or the healthy subjects. This may suggest that vaginal infection with C. albicans contributes to a rise in anti-proteinase antibody levels.

Adult↗
PubMed1992

Estimation of chromosome number and size by pulsed-field gel electrophoresis (PFGE) in medically important Candida species.

The chromosomal DNAs of eight medically important Candida species, C. albicans, C. stellatoidea, C. tropicalis, C. parapsilosis, C. krusei, C. guilliermondii, C. kefyr and C. glabrata, were analysed by pulsed-field gel electrophoresis under various conditions. The corresponding bands in the gels were assigned by three kinds of DNA probe which hybridized to DNA of all the species: rDNA, TUB2 and PEP4. The best conditions for separating the chromosomal DNAs were investigated and the numbers and molecular sizes of the chromosome bands were determined for each species. The chromosomal DNAs of the species were separated into 5-14 bands ranging in size from 0.5 to 4.5 Mb. Based on the quantification of the chromosome band intensities using a laser fluorescent gel scanner, the chromosome numbers were estimated. The apparent average total number of chromosomes per cell was 16 for C. albicans, 16 for C. stellatoidea, 12 for C. tropicalis, 14 for C. parapsilosis, 8 for C. krusei, 8 for C. guilliermondii, 18 for C.kefyr, and 14 for C. glabrata; the total chromosomal DNA size of each species per cell was calculated at about 31 Mb, 33 Mb, 31 Mb, 26 Mb, 20 Mb, 12 Mb, 29 Mb and 14 Mb, respectively.

Candida↗
PubMed1992

Detection of intracellular forms of secretory aspartic proteinase in Candida albicans.

The extracellular proteinase (EPR) of Candida albicans was induced in a medium containing bovine serum albumin as sole nitrogen source. There were two intracellular forms in cells induced to produce EPR, a 43 kDa protein (EPR) and a 45 kDa protein (cross-reacting material of EPR; CRM-EPR); these were detected by immunoblotting using anti-EPR antiserum. The 43 kDa protein (EPR) may be the same as the extracellular form judging by molecular mass, and the 45 kDa protein (CRM-EPR) may be a precursor form of EPR. Many dense granules were observed by electron microscopy near the plasma membrane of the mother cells in EPR-producing cells. Both the 43 and 45 kDa proteins were recovered in a membrane fraction and were solubilized by Triton X-100. When the membrane fraction was further fractionated by sucrose density gradient centrifugation, the 43 and 45 kDa proteins were differentially fractionated. This suggests that they were located in different membrane-bound structures and is consistent with an assumption that the 45 kDa protein is a precursor for EPR.

Aspartic Acid Endopeptidases↗
PubMed1992

Clonal variation of chromosome size derived from the rDNA cluster region in Candida albicans.

Of the eight Candida albicans chromosomes, chromosome 2, assigned by the MGL1 probe, is more variable in size than the other chromosomes among strains. We found that the clonal variation of chromosome 2, which carries a rDNA gene, occurred at a frequency of up to 10% of the progeny clones. After total chromosomal digestion with XhoI, which has no recognition sites within the rDNA repeat unit, the fragments containing the rDNA cluster were detected by Southern hybridization. The difference in fragment sizes corresponded to the clonal size variation of chromosome 2. The intensity of hybridization with rDNA also correlated with the difference in size. In addition, there was no size change in the non-rDNA region as detected by NotI digestion of chromosome 2, and there was no observed change in the individual rDNA basic repeat unit size. From these lines of evidence, we confirmed that the clonal size variation of chromosome 2 which occurs at high frequency is derived from the size change of the rDNA cluster.

Candida albicans↗
PubMed1992

Isolation and characterization of a repeated sequence (RPS1) of Candida albicans.

A repeated sequence, named RPS1, approximately 2 kb in size, is found mainly in chromosome 6, the second most variable chromosome among the eight chromosomes of Candida albicans. Most of the RPS1 units of chromosome 6 seem to be located within a single region of about 100 kb in strain FC18. In both strains FC18 and NUM812, a part of RPS1 is apparently tandemly repeated. A unit of RPS1 has been cloned and sequenced. It consists of 2114 bp and has a GC content of 40 mol%. The repeat unit contains smaller repeats of about 80-170 bp which are called REP1, REP2, REP3, REP4 and REP5; REP2 is duplicated. The small repeats are classified into two groups by their homology. One comprises REP1, REP2 and REP5, and the other REP3 and REP4. They are termed the REP1 and REP3 families, respectively. The two families both contain a common 29 bp sequence, called COM29. The dispersed repetitive sequence RPS1 may be involved in chromosomal rearrangements and may in part explain chromosome polymorphism in C. albicans. The origin of RPS1 was not determined.

Base Sequence↗
PubMed1992

Gelatin particle agglutination test for early serodiagnosis of Japanese spotted fever.

A gelatin particle agglutination (PA) test for Japanese spotted fever has been developed. Gelatin particles were sensitized with a sonicated causative rickettsia and used as antigens. The antibodies by PA test were detected as early as days 4-7 after the onset, whereas those by indirect immunoperoxidase (IP) test were detected after days 8-11. In addition, PA titers were higher than IP titers before days 20-23. The agglutinins detected by PA test were proven to be IgM because they were all sensitive to dithiothreitol. PA test was, however, less specific than IP test, giving a little nonspecific reaction to the sera from patients with scrub typhus and from individuals unrelated to those two rickettsioses. Nevertheless, PA test, which is simple, rapid, and easy to interpret the results, is useful for the early serodiagnosis of Japanese spotted fever.

Agglutination Tests↗
PubMed1992

Enteric adenovirus type 41 isolates: cloning, physical maps and diversity in restriction enzyme cleavage pattern.

Adenovirus (Ad) type 40 and 41 DNAs were directly extracted from stool specimens of children with gastroenteritis. Two new strains of Ad41, Sanekata and Ehime strain, were cloned and their restriction maps were constructed. The left terminal end of the cloned Ad41 genome, EcoRI-E fragment of the Sanekata strain and EcoRI-F fragment of the Ehime strain, had transforming ability in rat 3Y1 cells. Only one of the 35 isolates of Ad40 tested showed a different restriction profile, while three different restriction profiles were found in DNAs from Ad41 isolates.

Adenovirus Infections, Human↗
PubMed1992

Identification of Candida albicans antigens reactive with immunoglobulin E antibody of human sera.

Candida albicans antigens which reacted with immunoglobulin E (IgE) antibodies of 57 allergic patients were detected by immunoblotting. Of the various antigens, the 175-, 125-, 46-, 43-, and 37-kDa antigenic components reacted most frequently with the patient sera. To purify the major antigens, C. albicans cells were fractionated. The 46-, 43-, and 37-kDa antigens were recovered in cytoplasmic fractions, but the 175- and 125-kDa antigens were not recovered in any fraction. The 46-, 43-, and 37-kDa antigens were purified from cytoplasmic fractions by DEAE and P11 ion-exchange chromatography. Antigens were isolated by cutting bands out of sodium dodecyl sulfate-polyacrylamide gels. The purified components confirmed by immunoblotting were next processed for amino acid sequencing. Parts of the sequences of the 46-, 43-, and 37-kDa antigens had significant levels of homology with Saccharomyces cerevisiae glycolytic enzyme enolase, phosphoglycerate kinase, and aldolase, respectively. Rabbit IgG antibodies prepared against the 46- and 43-kDa antigens strongly cross-reacted with the homologous proteins of S. cerevisiae. However, S. cerevisiae enolase and phosphoglycerate kinase did not cross-react with IgE of patient sera. This result suggests that IgE antibodies against only small parts of their epitopes are elevated in the allergic patients. Since enolase is reported to be a major antigen for systemic candidiasis, this enzyme may be the immunodominant protein in both allergies and fungal infections.

Adolescent↗
PubMed1992

Glucocorticoid receptor and inhibition of 3-O-methyl-D-glucose uptake by glucocorticoids in peripheral blood leukocytes from normal humans: correlation between receptor level and hormone effect in vitro.

We have measured the glucocorticoid receptor concentration in mononuclear and polymorphonuclear leukocytes, both of which were isolated from peripheral blood from ten healthy male volunteers. In parallel, the inhibitory effect of dexamethasone on 3-O-methyl-D-glucose uptake was assayed in the corresponding mononuclear leukocytes. The glucocorticoid receptor levels in mononuclear leukocytes correlated with those in polymorphonuclear leukocytes, and there was a linear relationship between the cellular glucocorticoid receptor levels and glucocorticoid-mediated inhibition of the uptake of 3-O-methyl-D-glucose in mononuclear leukocytes. When mononuclear leukocytes were incubated in the presence of 8-bromo-cAMP, cellular glucocorticoid receptor levels increased and a more pronounced inhibitory effect of dexamethasone was observed on the transport of 3-O-methyl-D-glucose. We conclude that the cellular glucocorticoid receptor levels in peripheral blood leukocytes reflect in vitro responsiveness to glucocorticoids in mononuclear leukocytes from healthy males, and that the individual responsiveness may alter upon changes in the cellular levels of glucocorticoid receptor.

3-O-Methylglucose↗