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Biomedical subjects

M Iwaya

Publications and source records attributed to M Iwaya.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Study of cockroach allergy in asthmatic children. The positive rates and antigenicity of cockroach allergen].

The specific IgE antibodies to 4 species of cockroach were measured in sera from 51 asthmatic children 6 to 16 years old by RAST and CAP system. Positive rates of RAST to Periplaneta fuliginosa, Blattela germanica, Periplaneta americana and Periplaneta japonica were 17.6%, 29.4%, 19.6% and 15.7%, respectively and those of CAP system to Periplaneta fuliginosa and Blattela germanica were 15.7%, respectively. Among those with positive RAST to 4 species of cockroach there were significant correlations. Significant correlations were observed also between the RAST titer for the whole bodies and feces of Periplaneta fuliginosa and Blattela germanica and immunoblotting analysis of sera obtained from two cockroach-positive patients revealed common sensitive fraction between whole body and feces. Immediate bronchial response was detected by bronchial provocation test. RAST inhibition study indicated no cross-reacting allergenicity between cockroach and mite. Collectively, cockroach is one of important inhalent allergens in asthmatic children.

Adolescent↗
PubMed1994

[Bronchial hypersensitivity and development of bronchial asthma in children with atopic dermatitis].

Using histamine inhalation tests, we followed changes in bronchial hypersensitivity in 48 children with atopic dermatitis (AD) who were nonasthmatic on their initial visit. Twenty-three of these subjects became asthmatic during the follow-up period. The respiratory thresholds to histamine RT-Hist) of children with AD were widely distributed, ranging from 156 to more than 5000 micrograms/ml. There was a statistical difference in RT-Hist, as those who became asthmatic showed lower levels (< or = 625 micrograms/ml) at 2-6 yr of age. The percentage of peripheral eosinophil counts and IgE level was significantly elevated in those who became asthmatic. Subjects who developed asthma were more likely to have had positive D.p. RAST when they were less than 2 yr of age. The development of asthma in children with AD showed no significant relationship with family history of bronchial asthma.

Age of Onset↗
PubMed1994

[Bronchial hypersensitivity to histamine in asthmatic children longitudinal study from first visit to remitted state].

In order to examine the changes in bronchial hypersensitivity, histamine inhalation tests were evaluated in 27 asthmatic children who remitted. The respiratory threshold to histamine (RT-Hist) 2-3 yrs after remission was higher than in the initial test, in their worst periods of the asthma and just before remission (p < 0.001, p < 0.001, p < 0.005, respectively). Eleven subjects (40.7%), showed no improvement of bronchial hypersensitivity 2-3 yrs after remission (RT-Hist was 1250 micrograms/ml or lower). In this group, the asthma score per year two and three years before symptom-free state was higher than in the group with improved bronchial hypersensitivity (p < 0.05). There was no significant difference between % fall of FEV1.0 in RT-Hist in the worst periods of the asthma and 2-3 yrs after remission. FEV1.0/VCP, %V50, %V25 and V25/Ht 2-3 yrs after remission were higher than those in the worst periods of the asthma.

Adolescent↗
PubMed1994

[A case of anaphylaxis caused by sunflower seed].

A 14 years old boy experienced an anaphylactic reaction of dyspnea, vomiting, urticaria and hypotension after he ate sunflower seeds. Specific IgE-mediated hypersensitivity to sunflower seen extract was demonstrated by skin tests and radioallergosorbent test (RAST). By immunoblotting test analysis (SDS-PAGE, Western blotting method), the allergenic activity of sunflower seem were shown to be in the MW range of 13.5 Kd.

Adolescent↗
PubMed1991

Molecular studies of chronic myelogenous leukemia using the polymerase chain reaction.

Thirty-two cases of chronic myelogenous leukemia (CML) were studied to determine whether there was a correlation between the position of the chromosome breakpoint within the breakpoint cluster region (bcr) on chromosome 22 and the type of chimeric mRNA expression. One case with the chromosome breakpoint in zone 2 of the major bcr (Mbcr) and six cases with breakpoints in zone 3 expressed Mbcr exon 2-abl (b2-a) mRNA, and they were in distinguishable at the level of mRNA expression. The remaining ten cases with breakpoints in zone 3 and all ten cases with breakpoints in zone 4 expressed Mbcr exon 3-abl (b3-a) mRNA with or without b2-a mRNA. Three cases with breakpoints in zone 5 expressed b3-a mRNA, and none of these expressed Mbcr exon 4-abl(b4-a) mRNA. The cases with breakpoints in zones 4 or 5 had b3-a mRNA expression indistinguishable from those with breakpoints in zone 3. In two patients, the breakpoint in the bcr could not be determined by Southern hybridization using the 3' bcr probe or the large bcr probe. However, when analyzed for chimeric mRNA expression, both of them exhibited b3-a chimeric mRNA, suggesting the possibility that the entire Mbcr is deleted in the majority of leukemic cells in these patients. These studies indicate that Southern hybridization analysis combined with the polymerase chain reaction assay is a useful approach to understanding the pathologic role of bcr-abl gene recombination and expression in the development of CML.

Adolescent↗
PubMed1991

Sex identification by polymerase chain reaction using X-Y homologous primer.

A method of sex identification using the polymerase chain reaction technique is described. Using a pair of nucleotide primers from an X-Y homologous region, both the X and the Y sequences can be amplified simultaneously, and more importantly, they result in fragments of different lengths. The success of the procedure is therefore monitored by the presence of a X-specific band while sex is identified by the presence or absence of a Y-specific band.

Base Sequence↗
PubMed1991

A repeating unit of the DYZ1 family on the human Y chromosome consists of segments with partial male-specificity.

An average-sized human Y chromosome contains about 3,000 copies of the repeating DNA family DYZ1. A major repeating unit of the family, pHY10, has been cloned and an entire 3,564-bp sequence has already been determined by Nakahori et al. (1986). In the present study, pHY10 was divided into six consecutive segments, A to F, which were independently amplified by the PCR technique to see if they were strictly male-specific. pHY10 appears to consist of segments of various male-specificity. The B segment was apparently male-specific; however, the use of additional techniques (Southern-blot analysis or second PCR amplification in combination with the standard PCR) revealed homologous sequences in some females. None of the six segments of pHY10 may be male-specific in a strict sense. Different segments appear to be conserved during evolution to different extents. The 323-bp E segment appears to be the least conserved and to be responsible for the generation of most variations within the DYZ1 family.

Base Sequence↗
PubMed1991

Gene amplification of Japanese non-Hodgkin lymphoma with involvement of the BCL2 gene.

Twenty cases of Japanese non-Hodgkin's lymphoma with B cell markers were studied with respect to their immunoglobulin heavy (IgH) chain gene loci on chromosome 14 and BCL2 loci on chromosome 18. All of the 20 cases showed IgH gene rearrangement on at least one of the alleles. Molecular analysis using two chromosome 18-specific DNA probes (pFL1 and pFL2) showed rearrangement of the BCL2 region in three of 20 cases. As these three samples showed the rearranged allele of the IgH gene comigrating with that of the BCL2 gene, polymerase chain reaction (PCR) was carried out to amplify the juncture between IgJH on chromosome 14 and BCL2 on chromosome 18. In all of these three cases, gene amplification between the two loci was found to occur, indicating that molecular mechanisms involved in this type of chromosomal translocation in Japan might be similar to cases in the United States (U.S.) in a limited number of cases. Furthermore, this amplification technique revealed minimal tumor cells circulating in peripheral blood, even though lymphoma cells could not be identified morphologically. Thus, the PCR technique is useful for both the detection of minimal tumor cells as well as for the determination of the molecular nature of chromosomal translocation in some of Japanese cases.

Base Sequence↗
PubMed1979

Temperature-sensitive 6-aminopenicillanic acid-resistant mutants of Escherichia coli.

Wild-type Escherichia coli cells became spherical in the presence of low concentrations of 6-aminopenicillanic acid (APA). Higher concentrations of APA caused inhibition of cell division (filamentation) and lysis. Spontaneous temperature-sensitive APA-resistant mutants were isolated and characterized. These mutants also possessed increased resistance to mecillinam but not to benzylpenicillin, ampicillin, and cephaloridine. They formed round or pleomorphic cells at the nonpermissive temperature and possessed thermolabile penicillin-binding protein 2 activity. Temperature-resistant revertants of these mutants had normal rod-shaped morphology, normal levels of sensitivity to APA and mecillinam, and thermostable penicillin-binding protein 2 activity. The mutation conferring APA resistance cotransduced with lip and mapped, therefore, close to 14 min on the E. coli linkage map. APA appears to be more specific than mecillinam as a selective agent for the isolation of penicillin-binding protein 2 mutants.

Drug Resistance, Microbial↗
PubMed1978

Mapping of the mecillinam-resistant, round morphological mutants of Escherichia coli.

Genes responsible for round morphology in mecillinam-resistant, round morphological mutants of Escherichia coli have been mapped. Three mutants, called rodX, mapped at around 14 min, and two, called rodY, mapped at around 70 min by P1 transduction. These are either the same or very close to the loci reported, respectively, for the rodA (H. Matsuzawa, K. Hayakawa, T. Sato, and K. Imahori, J. Bacteriol. 115:436-442, 1973) and envB genes (B. Westling-Häggström and S. Normark, J. Bacteriol. 123:75-82, 1975). This suggests that mecillinam can be used very efficiently to select for found morphological mutants of rodA and envB after nitrosoguanidine treatment.

Amdinocillin↗
PubMed1978

Morphology of an Escherichia coli mutant with a temperature-dependent round cell shape.

Mutants of Escherichia coli capable of growing in the presence of 10 microgram of mecillinam per ml were selected after intensive mutagenesis. Of these mutants, 1.4% formed normal, rod-shaped cells at 30 degrees C but grew as spherical cells at 42 degrees C. The phenotype of one of these rod(Ts) mutants was 88% cotransducible with lip (14.3 min), and all lip+ rod(Ts) transductants of a lip recipient had the following characteristics: (i) growth was relatively sensitive to mecillinam at 30 degrees C but relatively resistant to mecillinam at 42 degrees C; (ii) penicillin-binding protein 2 was present in membranes of cells grown at 30 degrees C in reduced amounts and was undetectable in the membranes of cells grown at 42 degrees C. The mecillinam resistance, penicillin-binding protein 2 defect, and rod phenotypes all cotransduced with lip with high frequency. Thus the mutation [rodA(Ts)] is most likely in the gene for penicillin-binding protein 2 and causes the organism to grow as a sphere at 42 degrees C, although it grows with normal rodlike morphology at 30 degrees C. At 42 degrees C, cells of this strain were round with many wrinkles on their surfaces, as revealed by scanning electron microscopy. In these round cells, chromosomes were dispersed or distributed peripherally, in contrast to normal rod-shaped cells which had centrally located, more condensed chromosomes. The round cells divided asymmetrically on solid agar, and it seemed that the plane of each successive division was perpendicular to the preceding one. On temperature shift-down in liquid medium many cells with abnormal morphology appeared before normal rod-shaped cells developed. Few abnormal cells were seen when cells were placed on solid medium during temperature shift-down. These pleiotropic effects are presumably caused by one or more mutations in the rodA gene.

Amdinocillin↗
PubMed1977

Simultaneous deletion of D-alanine carboxypeptidase IB-C and penicillin-binding component IV in a mutant of Escherichia coli K12.

Mutants of Escherichia coli with much decreased activity of D-alanine carboxypeptidase (peptidyl-D alanine hydrolase, EC 3.4.12.11) were found among E. coli K12 extensively mutagenized with nitrosoguanidine treatment by assaying individual colonies for the enzyme activity. One such mutant with only 10-12% residual activity was characterized extensively. The soluble carboxypeptidase activity (corresponding to D-alanine carboxypeptidase IC of Tamura T., Imae, Y. & Strominger, J.L. [(1976) J. Biol. Chem. 251, 414-423] was deleted. This enzyme activity in the particulate fraction was markedly reduced but transpeptidase activity was normal. However, penicillin-binding component IV was deleted from the particulate fraction. Both the physiology and penicillin sensitivity of the organism were relatively normal, except that mutant cells were markedly more stable to penicillin-induced lysis, suggesting the possibility that carboxypeptidase IC really functions as an endopeptidase. The possible relationship of the deleted carboxypeptidase activity and the deleted penicillin binding component are discussed.

Ampicillin↗
PubMed1973

Mechanism of replication of single-stranded PhiX174 DNA. VII. Circularization of the progeny viral strand.

Linear phiX174 single-stranded DNA can be isolated from phiX phage particles produced under various conditions. About half of the linear strands have a dGMP residue at the 5' end, the remaining have roughly comparable amounts of dCMP, dTMP, and dAMP. The linear strands can be converted to covalently closed circular molecules by polynucleotide ligase, but only after they have been incubated with T4 DNA polymerase and deoxynucleoside triphosphates. Experiments with endonuclease R, the restriction enzyme from Haemophilus influenzae, indicated that the nucleotides incorporated into the DNA during this reaction were found predominantly in a limited region of the genome. The results suggest that the normal intermediate in single-stranded phiX174 DNA synthesis may be a single-stranded linear molecule which is shorter than unit length and is intrinsically capable of circularization.

Centrifugation, Density Gradient↗