Biomedical subjects

M Iha

Publications and source records attributed to M Iha.

9 recordsLinked to original sources

PubMed2000

Properties of fucoidan from Cladosiphon okamuranus tokida in gastric mucosal protection.

To elucidate the anti-ulcer potential of Cladosiphon fucoidan, anti-peptic activity, bFGF stabilizing activity and inflammatory properties of this and related substances were investigated. Anti-peptic activity was observed with this and other sulfated polysaccharides such as dextran sulfate, carrageenan, and Fucus fucoidan. However, non-sulfated polysaccharides such as mannan and dextran did not exert the anti-peptic activity. The loss of bFGF bioactivity was prevented by all sulfated polysaccharides tested except chondroitin sulfate, at pH 7.4 and at pH 4.0. At pH 2.0, only heparin protected the bFGF activity. The generation of superoxide by macrophages and PMNs was stimulated by dextran sulfate, carrageenan, and Fucus fucoidan, whereas Cladosiphon fucoidan, heparin and chondroitin did not. Dextran sulfate, carrageenan, and Fucus fucoidan also stimulated the secretion of TNFalpha from macrophages, while Cladosiphon fucoidan did not. Thus, Cladosiphon fucoidan is a sulfated polysaccharide without inflammatory action. These results suggest that Cladosiphon fucoidan is a safe substance with potential for gastric protection.

Animals↗

PubMed1999

HLA genes and haplotypes in Ryukyuans suggest recent gene flow to the Okinawa Islands.

Polymorphism of HLA genes was investigated in a population sample of Ryukyuans living on the main island of Okinawa (n = 197), in the southwestern islands of Japan. Serological typing was applied to class I loci (HLA-A, -B, and -C) and to HLA-DRB1; nucleotide sequence-level typing was performed using PCR microtiter plate hybridization and PCR single-strand conformation polymorphism methods. Ryukyuans showed a higher frequency of DRB1*0405 and lower frequencies of DRB1*1502 and DRB1*1302 compared with Hondo Japanese living on main islands. Principal components and phylogenetic analyses of 12 East Asian populations, including Ryukyuans, were performed based on the allele frequencies of HLA-A, -B, and -DRB1. In the principal components analysis 3 Japanese populations (Ryukyuans, Hondo Japanese, and Ainu) formed a cluster and showed the highest affinity to 2 Korean populations. In the phylogenetic tree Ryukyuans and Ainu were neighbors, but the genetic distance between them was larger than the distances between Ryukyuans and Hondo Japanese and between Ryukyuans and Korean populations. The geographic cline of the predominant haplotype in Ryukyuans, A*24-B*54-DRB1*0405, suggests that an ancestral population possessing A*24-B*54-DRB1*0405 moved into the Okinawa Islands after the divergence of Ryukyuans from the Ainu. Such a recent gene flow, probably from South China to the Okinawa Islands, is considered the major cause of difference in genetic characteristics between Ryukyuans and the Ainu.

Adult↗

PubMed1995

The primary structure of a hemorrhagic factor, HR2b, from the venom of Okinawa habu (Trimeresurus flavoviridis).

The complete amino acid sequence of a hemorrhagic factor, HR2b, from the venom of Okinawa habu was determined. The hemorrhagic factor was fragmented by CNBr cleavage, trypsin, staphylococcal protease V8 and lysyl endopeptidase digestions. The resulting peptides were purified on high performance chromatography, and sequenced by Edman degradation. HR2b was composed of 204 amino acids with pyroglutamyl residue at the amino terminus, and the calculated mol. wt based on the amino acid composition was 23,335. There are three disulfide linkages in the primary structure. The consensus sequence (His-Glu-Xaa-Xaa-His) for zinc-binding site of zinc-requiring metalloproteinases was found in the structure. The primary structure of HR2b shows a significant similarity with that of HR2a of Amami habu venom; 98.5% identity.

Amino Acid Sequence↗

PubMed1993

Helicobacter pylori infection and chronic atrophic gastritis among Japanese blood donors: a cross-sectional study.

To evaluate an association between Helicobacter pylori (H. pylori) infection and chronic atrophic gastritis (CAG), an established precursor of gastric cancer, we performed a cross-sectional study using IgG antibody against H. pylori and pepsinogens of blood donors in four prefectures in Japan. Although a geographic correlation between the age-adjusted prevalence rates for H. pylori infection and those for CAG was not seen, the age-adjusted odds ratios (OR) of H. pylori infection for CAG were high in each area (around five for men and from four to 12.6 for women). The association between them weakened with advancing age; the ORs in the youngest age group (16-29 yrs) and in the oldest age group (50-64 yrs) were 12.5 and 2.8 for men, and 11.5 and 5.2 for women, respectively. These findings suggest that H. pylori infection is strongly associated with CAG, while there are some other factors interacting in the development of CAG. A prospective cohort study in which CAG and H. pylori infection are taken into account will be necessary to assess the risks of gastric cancer.

Adolescent↗

PubMed1993

Correlation between the prevalence of gastritis and gastric cancer in Japan.

To verify the hypothesis that chronic atrophic gastritis (CAG) is a precancerous lesion for gastric cancer, we investigated the correlation between the prevalence rates for CAG determined by levels of serum pepsinogens (I and II) of randomly selected, healthy, blood donors and the mortality rates for gastric cancer among four prefectures (Akita, Iwate, Miyagi, and Okinawa) in Japan. The prevalence rates for CAG according to a criterion that the level of pepsinogen I is below 70 ng/ml and the pepsinogen I to pepsinogen II ratio is below 3.0, were the highest in Akita for both sexes (38.8 percent in males, 37.8 percent in females) and the lowest in Okinawa (13.9 percent in males, 12.3 percent in females), where mortality rates for gastric cancer are the highest and the lowest in Japan, respectively. The correlation between the prevalence rates for CAG and the standardized mortality ratios for gastric cancer among these four prefectures was statistically significant in males (r = 0.97, P = 0.03), but less significant in females (r = 0.92, P = 0.08). These data strongly support the hypothesis that CAG is a precancerous lesion. The limitations of our cross-sectional study and the advantages of measuring the levels of serum pepsinogens in epidemiologic studies and in mass-screening programs for gastric cancer are discussed.

Adolescent↗

PubMed1991

Characterization of three hemorrhagic factors from the venom of Okinawa habu (Trimeresurus flavoviridis).

Three hemorrhagic factors, HR1, HR2a and HR2b, of Okinawa habu venom were characterized in terms of their subunit structure, amino acid composition, metal content and immunological properties. HR1 is a dimer (mol. wt 90,000) consisting of two identical subunits at 25 degrees C, but polymerizes to form a tetramer at 4 degrees C. Two peaks corresponding to the dimer and the tetramer were observed upon ultracentrifugation analysis at 20 degrees C. HR2a and HR2b are monomers (mol. wt 24,000 and 19,000, respectively). HR1, HR2a and HR2b contain 407, 203 and 161 amino acids, respectively and the respective mol. wt based on the amino acid composition are 45,988, 23,075 and 18,457. The hemorrhagic factors contain Zn2+, Ca2+ and Mg2+, and were irreversibly inhibited by incubation with chelating reagents. The three hemorrhagic factors were immunologically distinguished from each other, and the hemorrhagic activities were inhibited by the respective antiserum. The activity of HR2a was also inhibited by the antiserum against HR2b.

Amino Acids↗

PubMed1990

Orosomucoid (ORM) typing by isoelectric focusing: an analysis of ORM haplotypes.

A new separator isoelectric focusing method for typing of orosomucoid (ORM) was developed. This method provided a superior resolution of ORM patterns: two close bands of ORM1*5.2 products were clearly separated. A total of 364 subjects from Okinawa (Japan) were classified into 21 ORM phenotypes determined by 6 ORM1 and 7 ORM2 alleles including a polymorphic silent allele, ORM2*QO, and 2 new rare variants, ORM2*18 and ORM2*19. These phenotypes were also explained by 12 ORM haplotypes, half of which were polymorphic.

Gene Frequency↗

PubMed1988

Purification and crystallization of hemorrhagic factor, HR2b, from the venom of Trimeresurus flavoviridis (habu).

The hemorrhagic factor, HR2b, was purified from the venom of Trimeresurus flavoviridis (habu) by a combination of gel filtration, cation exchange column chromatography and high performance liquid chromatography. The purified HR2b was homogeneous by the criteria of ultracentrifugation and SDS-disc electrophoresis. The mol. wt of HR2b was 18,000 and 18,500 by gel filtration on Sephadex G-50 and by SDS-disc electrophoresis, respectively, indicating a monomer structure for the hemorrhagic factor. Crystals of HR2b, taking the form of thin plates, were obtained in the presence of ammonium sulfate.

Animals↗

PubMed1988

Factor I (C3b inactivator) polymorphism among five populations in Eurasia.

Factor I (C3b inactivator) polymorphism in the Japanese (in Western and Southern Japan), Taiwanese, Nepalese and French was studied using isoelectric focusing on polyacrylamide gels. The exposure of passively blotted nitrocellulose membranes to glutaraldehyde vapor facilitated the subsequent immunodetection of a low concentration of factor I and permitted the reliable identification of the three phenotypes determined by two codominant alleles FI*A and FI*B. The data indicated a west-to-east genocline, ranging from France to Western Japan, in which FI*A changed from 0.006 to 0.120.

Alleles↗