Biomedical subjects

S Hata

Publications and source records attributed to S Hata.

At least 145 records · Page 8Linked to original sources

PubMed1991

Amino-terminal presequence of the precursor of peroxisomal 3-ketoacyl-CoA thiolase is a cleavable signal peptide for peroxisomal targeting.

To examine the function of the amino-terminal presequence of rat peroxisomal 3-ketoacyl-CoA thiolase precursor, fusion proteins of various amino-terminal regions of the precursor with non-peroxisomal enzymes were expressed in cultured mammalian cells. On immunofluorescence microscopy, all constructs carrying the presequence part exhibited punctate patterns of distribution, identical with that of catalase, a peroxisomal marker. Proteins lacking all or a part of the prepiece were found in the cytosol. These results indicate that the presequence of the thiolase has sufficient information for peroxisomal targeting.

Acetyl-CoA C-Acyltransferase↗

PubMed1991

Identification of epitopes recognized by a panel of six anti-human IgG2 monoclonal antibodies.

Human IgG2 contains several subclass specific amino acid residues or deletions in the CH1 and CH2 domains and also in the hinge region. These substituted residues are the structural correlates for IgG2 specific epitopes. Since human IgG2 has different biological properties from other subclasses, some IgG2 epitopes may be located in regions correlating with sites determining the biological functions. Previously, we produced three anti-IgG2 monoclonal antibodies (mAbs) with highly specific and interesting reactivities using improved immunization protocols. However, it has been almost impossible to identify epitopes conventionally, because human IgG2 is so resistant to proteolysis that various proteolytic fragments could not be isolated. In this study, we identified the epitopes recognized by anti-IgG2 mAbs by SDS-PAGE, Western blotting, amino acid sequence analysis and peptide/mAb binding ELISA, thus overcoming the need for fragment isolation. A panel of six anti-human IgG2 mAbs, including the current WHO/IUIS specificity standards (HP6002, HP6008, HP6014) and our own (HG2-6A, HG2-30F, HG2-56F), reacted with distinct epitopes. The residues essential to expression of the epitopes recognized by the mAbs were: Pro234, Val235 and Val309 for HG2-56F, HG2-30F and HP6008, respectively. HP6014 reacted with the epitope expressed by Thr214 and its neighboring residues. HG2-6A was reactive with the hinge region, and HP6002 was assumed to be directed against discontinuous epitopes requiring intact Fc for expression. Through these studies, the pepsin and papain cleavage sites of human IgG2 were also clarified.

Amino Acid Sequence↗

PubMed1991

cDNA cloning of a novel cdc2+/CDC28-related protein kinase from rice.

A cDNA clone, named R2, has been isolated by screening a rice cell cDNA library with a redundant oligonucleotide probe derived from the conserved ATP binding site of cdc2+/CDC28 protein kinases. The cDNA contained the entire coding sequence for a 424 amino acid polypeptide with a molecular mass of 47.6 kDa. The R2 mRNA, 2.1 kb in size, was expressed in both cultured rice cells and rice seedlings at similar levels. The predicted R2 protein has canonical motifs for ATP binding and catalysis, and is significantly homologous (up to 47%) to members of the cdc2+/CDC28 subfamily of serine/threonine protein kinase. The R2 protein is a novel member of the subfamily.

Amino Acid Sequence↗

PubMed1991

Highly conserved structure of proliferating cell nuclear antigen (DNA polymerase delta auxiliary protein) gene in plants.

In a previous paper [Suzuka, I., Daidoji, H., Matsuoka, M., Kadowaki, K., Takasaki, Y., Nakane, P. K. & Moriuchi, T. (1989) Proc. Natl Acad. Sci. USA 86, 3189-3193], we demonstrated the presence of a rice genomic-DNA fragment which hybridized with a rat proliferating-cell nuclear antigen (PCNA) cDNA probe, and proposed that plants possess the homolog of the PCNA gene which plays an essential role in DNA replication in mammals. Here we show that the sequence of the rice PCNA gene supports this proposal. The rice gene consists of four exons. The 5'-flanking region contains a variety of sequences similar to several consensus sequences believed to be important for the regulation of gene expression in eukaryotes. Determination of the transcription-start site and the structure of the 3'-flanking region of the gene indicated that the coded mRNA is 1073 bases. The rice PCNA genomic and cDNA clones are composed of 789 nucleotides; they encode a putative protein of 263 amino acids having a molecular mass of 29275 Da. Comparison of the coding regions of rice PCNA and rat PCNA revealed about 64% similarity at the nucleotide level and about 62% similarity at the amino acid level. Furthermore, comparison of the predicted amino acid sequence of the soybean PCNA with the rice PCNA sequence indicated a high degree of similarity (88%). The structural similarity between PCNA from plants and animals, despite the distant evolutionary relationship, indicates a strong selection pressure for conservation of this structure and suggests the presence of conserved DNA-replication mechanisms throughout the eukaryotes.

Amino Acid Sequence↗

PubMed1991

Isolation and characterization of cDNA clones for plant cyclins.

We have isolated and sequenced a carrot cDNA and two soybean cDNAs encoding mitotic cyclin homologs. The soybean clones were derived from nearly identical cognate genes. The carrot cyclin and soybean cyclins were slightly more similar to A-type and B-type cyclins thus far defined, respectively. However, they had divergent amino acid sequences in the portion that is most highly conserved in known cyclins and we could not easily include them in either of the phylogenetic types. Since the homology between carrot and soybean cyclins was low, each of them might define a novel and distinct type. The mRNA of carrot cyclin, 1.5 kb in length, was expressed concomitant with somatic embryogenesis of cultured cells. Expression of soybean cyclin mRNAs, 1.6 kb in length, was localized in proliferating parts of seedlings. As in the case of cyclin genes of marine invertebrates, microinjection of a synthetic mRNA for the soybean cyclin induced the maturation of Xenopus oocytes. Other cyclin genes may be present because, on Southern blot analysis of soybean genomic DNA, the isolated soybean cDNA probe hybridized with additional genes under low stringency.

Amino Acid Sequence↗

PubMed1990

Anti-oxidative profile of lobenzarit disodium (CCA).

The effects of lobenzarit disodium (CCA) on various species of activated oxygen were investigated in chemiluminescence experiments. CCA showed a quenching effect against hydroxyl radicals generated by Fenton reaction. The inhibition of CCA was much more intense than that of mefenamic acid which is an anti-inflammatory drug and an analogous compound to CCA. CCA also showed a quenching effect against singlet oxygen generated in enzymatic systems. However, CCA had no effect against superoxide anion radicals generated in the xanthine oxidase-hypoxanthine system. As a model of lipid peroxidation and protein alteration induced by activated oxygen, we examined the auto-oxidation of linolenic acid and the UV irradiation of immunoglobulin G (IgG). CCA inhibited the production of lipid peroxide; however CCA did not show a direct quenching action against lipid radicals which had been previously generated. CCA also inhibited the IgG alteration induced by UV irradiation. These results indicate that CCA has anti-oxidative actions with specificity for activated oxygen species and that CCA protects against lipid and protein damage induced by activated oxygen.

Antioxidants↗

PubMed1990

Suppression of developmental anomalies by maternal macrophages in mice.

We tested whether nonspecific tumoricidal immune cells can suppress congenital malformations by killing precursor cells destined to cause such defects. Pretreatment of pregnant ICR mice with synthetic (Pyran copolymer) and biological (Bacillus Calmette-Guérin) agents significantly suppressed radiation- and chemical-induced congenital malformations (cleft palate, digit anomalies, tail anomalies, etc.). Such suppressive effects were associated with the activation of maternal macrophages by these agents, but were lost either after the disruption of activated macrophages by supersonic waves or by inhibition of their lysosomal enzyme activity with trypan blue. These results indicate that a live activated macrophage with active lysosomal enzymes can be an effector cell to suppress maldevelopment. A similar reduction by activated macrophages was observed in strain CL/Fr, which has a high spontaneous frequency of cleft lips and palates. Furthermore, Pyran-activated maternal macrophages could pass through the placenta, and enhanced urethane-induced cell killing (but not somatic mutation) in the embryo. It is likely that a maternal immunosurveillance system eliminating preteratogenic cells allows for the replacement with normal totipotent blast cells during the pregnancy to protect abnormal development.

Abnormalities, Drug-Induced↗

PubMed1990

A T cell-specific transcriptional enhancer within the human T cell receptor delta locus.

The T cell antigen receptor (TCR) delta gene is located within the TCR alpha locus. A T cell-specific transcriptional enhancer, distinct from the TCR alpha enhancer, has been identified within the J delta 3-C delta intron of the human T cell receptor delta gene. This enhancer activates transcription from the V delta 1 and V delta 3 promoters as well as from heterologous promoters. Enhancer activity has been localized to a 250-bp region that contains multiple binding sites for nuclear proteins. Thus, transcriptional control of the TCR delta and TCR alpha genes is mediated by distinct regulatory elements.

Base Sequence↗

PubMed1990

A selected ion monitoring method for quantifying simvastatin and its acid form in human plasma, using the ferroceneboronate derivative.

Simvastatin, a pro-drug lactone, forms the open carboxylic acid as a major metabolite that inhibits the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase. Simvastatin and the acid in plasma were quantified by a gas chromatography/mass spectrometry/selected ion monitoring (GC/MS/SIM) method. These drugs were separated by solid-phase extraction and independently converted into a 1,3-diol-type compound. This compound reacted with ferroceneboronic acid to yield the cyclic boronate that gave satisfactory mass spectra for GC/MS/SIM measurements. The serum was dominated by the molecular ion appearing as the base peak, thereby leading to a sensitive and selective assay. The calibration curves for simvastatin and the acid were linear in their concentration range of 0.1-10 ng ml-1, where the values of coefficient of variation for both drugs were below 8%, except for the value of 11% for simvastatin at a concentration of 0.1 ng ml-1. The quantification limit for both drugs was 0.1 ng ml-1 on the basis of a signal-to-noise ratio of 4:1.

Ferrous Compounds↗

PubMed1990

Gene cloning of an Actinobacillus actinomycetemcomitans Y4 antigen which reacts with peripheral blood sera in patients with advanced destructive periodontitis.

Actinobacillus actinomycetemcomitans has been implicated in the aetiology of juvenile periodontitis and advanced destructive periodontitis. Levels of IgG antibody against A. actinomycetemcomitans in peripheral blood sera of patients with advanced destructive periodontitis are high, as are those against Bacteroides gingivalis. To clone the genes of antigens reactive with sera of such patients, a library of the A. actinomycetemcomitans strain Y4 DNA in lambda L47 was constructed and then screened, using an immunochemical detection method, with serum from a patient with the advanced disease. Six clones from among nearly 1000 reacted with the serum and also with that of another patient. They were designated 3, 4, 6, 7, 8 and 9. Restriction enzyme and Southern blot analyses indicated that clones 8 and 9 were identical and that all the clones were overlapping because they shared in common the 4 and 5 kbp HincII DNA fragments of A. actinomycetemcomitans. The cloned DNA fragment hybridized to the DNA of two other strains of A. actinomycetemcomitans but not to those of six periodontopathic bacteria examined. These findings suggest that a DNA sequence encoding an A. actinomycetemcomitans strain Y4 antigen strongly reactive with sera of patients with advanced destructive periodontitis was cloned. This sequence is present specifically in A. actinomycetemcomitans but not in other bacteria isolated from patients with periodontal diseases. Thus, the cloned DNA could serve as a probe for the diagnosis of periodontitis.

Actinobacillus↗

PubMed1990

Unusual varicella zoster virus infection in a patient with colon carcinoma and Evans syndrome--delayed virus shedding generalized recurrent necrotic herpes zoster.

A 53-year-old Japanese woman with Evans syndrome and colon cancer had two episodes of herpes zoster. The first painful vesicular rashes involved the right lower abdomen and buttock and healed in one month. After one more month, a second attack occurred on the right thigh and leg and developed into generalized hemorrhagic lesions, which became crusted in about 90 days. The patient died 131 days after the second attack, when the lesions had almost subsided. Varicella-zoster virus (VZV) was isolated on the 59th day of the second attack. Her intracutaneous reactions to VZV antigen was negative, but the humoral antibodies were continuously positive.

Anemia, Hemolytic↗

PubMed1990

Sebaceous trichofolliculoma on scrotum and penis.

A case of unique sebaceous trichofolliculoma on scrotum and penis is reported. Until now, this tumor has been reported as a solitary tumor only on the nose. The patient showed many small soft nodules for several years, then they became large, while some of them amassed. Histological examination showed many cystic cavities with many sebaceous follicles connected to them. No cell atypia or recurrence after excision was noted. A diagnosis of sebaceous trichofolliculoma was made based on histological findings.

Adult↗

PubMed1990

Biochemical mechanisms of enhanced inhibition of fluoride on the anaerobic sugar metabolism by Streptococcus sanguis.

The effect of fluoride on acid production by Streptococcus sanguis ATCC 10556 was compared under anaerobic and aerobic conditions. The rate of acid production under constant-pH and pH-free-fall conditions was determined during glucose metabolism by resting cells. Anaerobic glycolysis was inhibited more strongly by fluoride than was aerobic glycolysis. Intracellular levels of 3-phosphoglyceric, 2-phosphoglyceric, and phosphoenolpyruvic acids were lower under anaerobic conditions than under aerobic conditions. Thus, S. sanguis had a low phosphoenolpyruvate (PEP) potential under anaerobic conditions. This low PEP potential was suggested to account for the more effective fluoride inhibition of enolase and, consequently, the reduced transport of sugar by the PEP-dependent phosphotransferase system of this micro-organism.

Fluorides↗

PubMed1989

A novel polypeptide secreted by activated human T lymphocytes.

We have identified two cDNA clones, I-309 and G-26, which define genes expressed abundantly in activated human PBMC, but at low or undetectable levels in resting PBMC. Based upon nucleotide sequence analysis, both clones are predicted to encode small, structurally related polypeptides, each containing a hydrophobic leader sequence characteristic of secreted proteins and a motif of four conserved cysteine residues. Further, I-309 and G-26 are structurally related to a growing family of genes that apparently encode small polypeptides whose secretion is induced upon cell activation. I-309 represents a previously undescribed human gene. We have generated an anti-peptide antiserum to the I-309 gene product which recognizes proteins in culture supernatants of an activated T cell clone and of COS cells transfected with the I-309 cDNA, supporting the idea that I-309 encodes a secreted protein. Because I-309 encodes a small protein secreted by activated T cells that displays structural features similar to other cytokines, we believe that it defines a novel cytokine with as yet unknown function.

Amino Acid Sequence↗

PubMed1989

Diversity and organization of human T cell receptor delta variable gene segments.

Previous studies of the human TCR-delta gene identified a single commonly used V delta segment, denoted V delta 1. To better understand the extent of the human TCR-delta V gene repertoire, TCR-delta transcripts and gene rearrangements were examined in a new panel of cloned human TCR-gamma/delta lymphocytes. Through this analysis we identified and determined the structures of two new V delta segments, denoted V delta 2 and V delta 3. These V delta segments are different from previously characterized V alpha segments, supporting the notion that the human V delta and V alpha repertoires are distinct. Examination of V gamma gene segment usage in these cells reveals that the V delta 2 gene segment is used in conjunction with the V gamma 2 gene segment. Blot hybridization indicates that the V delta 2 gene segment lies between V delta 1 and D delta-J delta-C delta, and within 100 kb of the latter. Analysis of genomic clones indicates that the V delta 3 gene segment lies in an inverted orientation, approximately 2 kb 3' of C delta. This implies that rearrangement of V delta 3 to D delta-J delta-C delta occurs by inversion. Together with previous mapping studies, these results indicate that human V delta segments are dispersed, rather than clustered, within the TCR-alpha/delta locus. The analysis of rearrangements in polyclonal thymocyte DNA suggests that there may be a limited number of additional V delta gene segments yet to be characterized.

Amino Acid Sequence↗

PubMed1989

Detection of human papillomavirus type 16 DNA and papillomavirus genus-specific antigens in vulva and cervix from patients with Bowenoid papulosis.

The warty disordered lesions of the vulva in three female patients were diagnosed as Bowenoid papulosis on the basis of clinical and histopathological findings. In all three vulvar lesions, human papillomavirus type 16 (HPV 16) DNA was identified by Southern blot hybridization and papillomavirus genus-specific (PGS) antigen was detected in one case immunohistochemically. Furthermore, colposcopic examination revealed the presence of abnormal uterine cervical lesions in two cases. They were found to be intraepithelial neoplasia which harbored HPV 16 DNA and were positive for PGS antigen.

Adult↗

PubMed1989

[Geographic localization of three variants of herpes simplex virus type 1 in Japan].

We previously reported that a variant of herpes simplex virus type 1 (HSV-1) designated variant type A was isolated at a much higher frequency in Western Japan than in Eastern Japan. We examined the localization of two other variant types designated B and C. The proportion of the type B and type C variants among 553 fresh HSV-1 isolates from 10 areas in Japan were 5.4% and 1.3%, respectively. The isolation frequency of type B variant in Eastern Japan was 8.3%. It was as high as 20.5% in Iwate area. The frequency in Western Japan was only 3.0%. Type C variant showed no specific geographic localization. These results were discussed in terms of characteristic mode of HSV infection and the history of the Japanese nation.

Genetic Variation↗

PubMed1989

Difference in amounts between titratable acid and total carboxylic acids produced by oral streptococci during sugar metabolism.

The acid produced by the resting cells of Streptococcus mutants NCTC 10449 and HS 6 and S. sanguis ATCC 10556 during sugar metabolism was estimated with a pH-stat and a carboxylic acid analyzer. Lactic, formic, acetic, pyruvic, and carbonic acids were detected in the reaction mixtures, but propionic, citric, succinic, iso-butyric, butyric, iso-valeric, and valeric acids were not detected. The amount of titratable acid estimated by alkaline titration with the pH-stat was larger than the amount of total carboxylic acids estimated with the carboxylic acid analyzer. The difference in quantity between the titratable and the total carboxylic acids increased significantly with an increase in the period of incubation with sugar. Moreover, the value of the alkaline titration of standard lactic, formic, acetic, and pyruvic acids was equal to the amount analyzed with the carboxylic acid analyzer. The results indicated that these two streptococci produced not only these carboxylic acids but also other acid(s), possibly non-carboxylic acid(s), during their sugar metabolism.

Carboxylic Acids↗