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Biomedical subjects

S Yamai

Publications and source records attributed to S Yamai.

At least 73 records · Page 4Linked to original sources
PubMed1989

Entamoeba polecki infection in a Southeast Asian refugee in Japan.

We report the first human case of Entamoeba polecki infection found in Japan. Cysts of E. histolytica-like amoeba were detected in a stool sample from a female Cambodian refugee. The cysts were morphologically investigated after stained by the modified Kohn's method. The amoeba was identified as E. polecki by the findings that the cyst had frequently an inclusion mass, usually one or very rarely two nuclei, frequently a darkly stained nucleus, and some other characteristics. This protozoan parasite is essentially non-pathogenic to humans, but it is morphologically similar to and often confused with E. histolytica, a pathogenic species. Therefore, it is very important in laboratory diagnosis to differentiate the former from the latter.

Adult↗
PubMed1981

Preservation and transportation of bacteria by a simple gelatin disk method.

A wide range of bacterial species, e.g., Enterobacteriaceae and Neisseria, Streptococcus, Branhamella, Haemophilus, Gemella, Pseudomonas, Flavobacterium, and Bacteroides species, were successfully preserved for 1 to 5 years by our gelatin disk drying method. The beta-lactamase activity of penicillinase-producing Neisseria gonorrhoeae was retained for more than 3 years with this method. Good results were also obtained upon airmailing many strains of N. gonorrhoeae embedded in gelatin disks from Japan to the United States. Neisseria, Branhamella, Gemella, and Haemophilus organisms suspended in the reagent used in the preparation of the gelatin disks could be preserved for 6 to 12 months after freezing the cell suspensions at -20 degrees C. Furthermore, modification of our gelatin disk preservation method made possible the safe long- and short-distance transportation of clinical isolates. Our methods can be used by any small laboratory, since they require only conventional instruments and reagents.

Bacterial Infections↗
PubMed1980

Simplified purification and biophysicochemical characteristics of Kanagawa phenomenon-associated hemolysin of Vibrio parahaemolyticus.

Kanagawa phenomenon-associated hemolysin (K-hemolysin) was purified by Sephadex gel and ion-exchange column chromatography, after the culture supernatant had been adsorbed on and eluted from diethylaminoethyl-Sepharose CL-6B, and acid precipitated. K-hemolysin was a heat-stable and trypsin-susceptible protein with an apparent molecular weight of 44,000, the subunit of which was 22,000. The isoelectric point was 4.9. The minimum hemolytic dose was 0.1 mug/ml. The fifty percent lethal dose by intravenous injection was 1.4 mug. Electron microscopy of the small intestine of suckling mice orally challenged with the highest dose (50 mug) not only showed disappearance of epithelial cell microvilli, but also structural disturbances of the endoplasmic reticulum and mitochondrial swelling. One blueing dose representing permeability factor activity was 0.3 mug, and positive reaction in the rabbit ileal loop appeared at above 125 mug. Besides these data in experimental models, we discovered the appearance of an antibody in patients which neutralizes K-hemolysin during the course of the disease. This finding reinforces our view that K-hemolysin plays a most significant role in the pathogenesis of this enteric human disease.

Amino Acids↗
PubMed1979

Preservation of Neisseria gonorrhoeae by the gelatin-disc method.

Studies of Neisseria gonorrhoeae are difficult to perform because of the organism's poor survival in vitro. To solve this problem we tried to preserve the organism by a gelatin-disc method. The rate of survival and changes of variations in some biochemical properties of eight strains of N. gonorrhoeae were followed for three years. These studies proved that preservation was satisfactory with only a 1/10 reduction of the living cells. Another trial showed that the organism survived for over six months after being frozen at -20 degrees C. The colonial types, agglutination against red cells from rabbit and guinea pig, and antibiotic susceptibility to penicillin, chloramphenicol, tetracycline, kanamycin, and streptomycin did not change after three years' preservation.

Anti-Bacterial Agents↗