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Biomedical subjects

M Ikawa

Publications and source records attributed to M Ikawa.

At least 73 records · Page 4Linked to original sources
PubMed1985

A combination fluorescence assay and Folin-Ciocalteau phenol reagent assay for the detection of paralytic shellfish poisons.

Paralytic shellfish poison (PSP) profiles of crude shellfish extracts were determined by linear gradient elution from a Bio-Rad AG-50-X4 strong cation-exchange resin mini-column. STX, GTX2 and GTX3 were detected by fluorescence assay. NeoSTX and GTX1/GTX4 were detected with a Folin-Ciocalteau phenol reagent assay. The major toxicity associated with extracts of Mytilus edulis and Mya arenaria collected during a 1972 red tide off Hampton, New Hampshire, was due to the presence of GTX1/GTX4, with some activity associated with neoSTX, GTX2 and GTX3. STX was also present. Correlations to mouse toxicity are provided.

Amino Acids↗
PubMed1985

Trichothecene structure and toxicity to the green alga Chlorella pyrenoidosa.

Using the paper-disk method with Chlorella-seeded agar plates, 15-acetoxyscirpenol, HT-2 toxin, acetyl T-2 toxin and neosolaniol inhibited growth at a concentration of 1 mg/ml, whereas verrucarol, T-2 tetraol, nivalenol, fusarenon-X, deoxynivalenol and 3-acetyldeoxynivalenol were inactive. Taking into account that verrucarin A, roridin A, T-2 toxin and diacetoxyscirpenol had previously been found to strongly inhibit Chlorella growth, esterification at R15 appears to be important for growth inhibitory activity. The most active agents are also esterified at R4. Inhibition of protein synthesis appears to be involved in the toxicity.

Chlorella↗
PubMed1984

Molecular abnormality of an inactive aldehyde dehydrogenase variant commonly found in Orientals.

Usual human livers contain two major aldehyde dehydrogenase [(ALDH) aldehyde:NAD+ oxidoreductase] isozymes--i.e., a cytosolic ALDH1 component and a mitochondrial ALDH2 component--whereas approximately equal to 50% of Orientals are "atypical" and have only the ALDH1 isozyme and are missing the ALDH2 isozyme. We previously demonstrated that atypical livers contain an enzymatically inactive but immunologically crossreactive material (CRM) corresponding to the ALDH2 component. The enzymatically active ALDH2 obtained from a usual liver and the CRM obtained from an atypical liver were reduced, S-carboxymethylated, and digested by trypsin. Separation of their digests by high-performance reverse-phase chromatography and by two-dimensional paper chromatography and electrophoresis revealed that ALDH2 contained a peptide sequence of -Glu-Leu-Gly-Glu-Ala-Gly-Leu-Gln-Ala-Asn-Val-Gln-Val-Lys- and that the glutamine adjacent to lysine was substituted by lysine in CRM. All other tryptic peptides, including eight peptides containing S-carboxymethylcysteine, were common in ALDH2 and CRM. It is concluded that a point mutation in the human ALDH2 locus produced the glutamine leads to lysine substitution and enzyme inactivation.

Aldehyde Dehydrogenase↗
PubMed1983

Isolation and characterization of aldehyde dehydrogenase isozymes from usual and atypical human livers.

Usual human livers contain two major aldehyde dehydrogenase isozymes, cytosolic ALDH1 component and mitochondrial ALDH2 component, while human livers with "atypical" phenotype have only ALDH1 isozyme and are missing ALDH2 isozyme. Approximately 50% of orientals are atypical in respect to ALDH isozymes. We previously demonstrated an existence of enzymatically inactive but immunologically cross-reactive material (CRM) in atypical oriental livers. ALDH1 and ALDH2 isozymes were purified to homogeneity from usual livers, and ALDH1 and CRM were purified from atypical oriental livers. Amino acid compositions of ALDH1 and ALDH2 were similar to, but not identical with, each other. Amino acid compositions of ALDH2 and CRM were identical within analytical errors. Subunit molecular size of ALDH1 estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 56,200 daltons, and that of ALDH2 was 52,600 daltons. The two isozymes did not contain a common subunit. Subunit molecular weight of CRM was identical with that of ALDH2. Double immunodiffusion precipitation revealed that ALDH1 and ALDH2 were immunologically analogous but not identical, and that CRM and ALDH2 were immunologically indistinguishable. These results support the genetic model that CRM is an abnormal defective protein resulting from a mutation of the ALDH2 locus.

Aldehyde Dehydrogenase↗
PubMed1982

Change of enzyme properties caused by cross-linking treatment of human erythrocytes.

Aragon et al [4] reported that rat erythrocytes can be cross-linked and permeabilized without significant inactivation or alterations of several enzymes in the glycolytic pathway. If this is the case, in situ kinetic analysis of the red cell enzymes in normal human red cells and abnormal red cells associated with hemolytic problems could be performed. However, we found that the treatment of human red cells with several bifunctional cross-linking reagents under various conditions always caused a certain extent of inactivation and a change in kinetic properties of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and lactate dehydrogenase. Thus, the cross-linking and permeabilization method, as it stands, is not satisfactory for in situ kinetic analysis of red cell enzymes.

Cell Membrane Permeability↗
PubMed1982

Comparison of the toxins of the blue-green alga Aphanizomenon flos-aquae with the Gonyaulax toxins.

A toxic strain of Aphanizomenon flos-aquae (NH-1), isolated from a toxic bloom in a pond in Durham, New Hampshire, has been mass cultured in the laboratory. The toxin was extracted by ultrasonic disruption of the cells and purified by; (a) filtration through a 10 kilodalton filter, and (b) chromatography on a strong cation exchange resin column using 0.01 M, then 0.1 M, pH 5, sodium acetate buffer followed by 0.75 M hydrochloric acid. Mouse assays and fluorescence generated by hydrogen peroxide oxidation were used to monitor the fractions. Only a nonfluorescent toxic peak followed immediately by a fluorescent less-toxic peak were detected, both eluting with the hydrochloric acid fractions. The toxins were identical in behavior to neosaxitoxin and saxitoxin, respectively, when compared with elution profiles of the paralytic shellfish poisons from Gonyaulax tamarensis var. excavata and by paper electrophoretic and thin-layer chromatographic comparisons. The toxin profile appears to be different from that of a previously isolated strain of A. flos-aquae from Kezar Lake.

Animals↗
PubMed1982

[Experimental and clinical studies of cefmenoxime in the field of obstetrics and gynecology].

The study group was organized to evaluate the usefulness of cefmenoxime (CMX) injection, a new synthetic cephalosporin, for the treatment of infections in the field of obstetrics and gynecology. Fundamental and clinical studies were made by the society and the following results were obtained. 1. The peak distribution of CMX's MIC for E. coli, Klebsiella sp., Enterobacter sp., Bacteroides sp. and Peptococcus sp. isolated from obstetrical and gynecological infections with relatively high frequencies area 0.1, less than or equal to 0.05, 0.2, 3.13, 1.56 micrograms/ml, respectively, with an inoculation of 10(6) cells/ml. 2. When 1 g of CMX is administered by intravenous drip infusion for 1 hour, the maximum concentrations in various tissues of female genital organs were as follows: 14.2 and 13.2 micrograms/g in ovary and oviduct, respectively, at 1.20 hours after the start of administration, and 16.9 and 26.3 micrograms/g in corpus uteri and cervix uteri, respectively, after 1 hour. As for the transfer to the exudate in the pelvic dead cavity, the peak concentration was 15.6 micrograms/ml after 2.13 hours. 3. In the clinical studies, CMX was given to 258 cases with female genital organ infections and others. As for the clinical effects, with exclusion of 3 cases in which other antibiotics are concomitantly used, responses were excellent in 76 cases, good in 162 cases and poor in 17 cases, among 255 cases in total. The efficacy rate was 93.3%. The efficacy rates by diseases were 97.1% (68/70) for intrauterine infections, 88.8% (79/89) for intrapelvic infections, 98.4% (62/63) for adnexitis, and 100% (23/23) for infections of external genital organs. As for the clinical effects on causative bacteria, the efficacy rates were 100% (19/19) for single infections due to Gram-positive bacteria, 94.8% (55/58) for single infections due to Gram-negative bacteria, and 88.2% (15/17) for single infections due to anaerobic bacteria. And its efficacy rates were 89.6% (69/77) for mixed infection cases. Side effects were observed in 2 cases (0.8%); 1 case with eruption, and 1 case with diarrhea and vomiting. As for abnormal laboratory findings, lower white blood cell count was observed in 2 cases and elevation of the values regarding hepatic functions in 9 cases. All cases were returned to the normal after the completion of the administration. Cefmenoxime showed a satisfactory clinical efficacy and a potent bacteriological effect in treatment of the infections in the field of obstetrics and gynecology, and it has been concluded that cefmenoxime will be useful addition to the antibiotics for the therapy of these infections.

Adolescent↗
PubMed1980

Effect of fatty acids on action of polyene antibiotics.

Fatty acids cause a decrease in the absorption spectra of the antifungal polyene macrolide antibiotics nystatin, filipin, candicidin, and amphotericin B. For nystatin, filipin, and candicidin, this decrease in absorption could be correlated with the activity of the fatty acids in protecting the yeast Saccharomyces cerevisiae against the action of these antibiotics. With amphotericin B a correlation was observed between the decrease in absorption caused by certain derivatives of fatty acids and the protective action of these derivatives against the activity of amphotericin B on yeast. It is concluded that, like the sterols, fatty acids also interact with the polyene antibiotics and thereby reduce their effective concentrations.

Amphotericin B↗