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S Isomura

Publications and source records attributed to S Isomura.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Epidemiology of pertussis and studies on culture positive pertussis cases in Japan].

The number of pertussis patients has decreased steadily in the late 1960s and was extremely small in early 1970s. During 1973-74 the first national survey on pertussis cases confirmed by culture was conducted, when whole cell pertussis vaccine was used. The study revealed that 33.3% of culture positive cases had 2-4 doses of DT combined with whole cell pertussis vaccine. Acellular pertussis vaccine was introduced in 1981 and for the last several years the number of pertussis patients became low for the second time. During 1988-92 exactly the same study was conducted as the previous one. Among 2501 pertussis cases diagnosed clinically 403 were culture positive. Most of the patients were below 1 year of age. Most of the patients were below 1 year of age. Clinical symptoms of those infants were more serious than those of older children. Only 7 out of 403 (1.8%) had a history of 2-4 doses of DT combined with acellular pertussis vaccine. This proved that the acellular pertussis vaccine is by far more effective than the whole cell pertussis vaccine. Serotypes of 377 Bordetella pertussis were identified and 370/377 (98.1%) were serotype 1-3 group.

Adolescent↗
PubMed1996

Sequence variation in the 18S rRNA gene, a target for PCR-based malaria diagnosis, in Plasmodium ovale from southern Vietnam.

Field surveys of malaria were performed in southern Vietnam by using an acridine orange staining method for rapid diagnosis and a PCR-based, microtiter plate hybridization method for accurate diagnosis. A total of three patients of Plasmodium ovale infection were detected, but PCR-amplified DNA of the P. ovale isolates from two of the patients did not hybridize with the P. ovale-specific probe. Analysis of the target sequence in the 18S rRNA gene indicated that in the DNA of isolates from both patients three nucleotides in the probe region from the typical P. ovale sequence were different, with deletions of two nucleotides and the substitution of one nucleotide. These results may suggest that in addition to molecular biological methods, careful microscopic examination of stained thin blood films is still required in studies of the prevalence of different malaria species.

Animals↗
PubMed1995

Bactericidal effect of rat cystatin S on an oral bacterium Porphyromonas gingivalis.

We tested antibacterial and antiviral activities of rat cystatin S, a cysteine proteinase inhibitor, belonging to the family 2 cystatins against 18 different bacterial species and poliovirus type 1 (Sabin). Rat cystatin S specifically inhibited the growth of a human oral anaerobic bacterium Porphyromonas gingivalis due to a bactericidal effect.

Amino Acid Sequence↗
PubMed1995

Isolation of cytopathic small round virus (Aichi virus) from Pakistani children and Japanese travelers from Southeast Asia.

Aichi virus was isolated in Vero cells from 5 (2.3%) of 222 Pakistani children with gastroenteritis but none was found in 91 healthy children. Aichi virus was also isolated from 5 (0.7%) of 722 Japanese travelers returned from tours to Southeast Asian countries and complained of gastrointestinal symptoms at the quarantine station of Nagoya International Airport in Japan. Of 5 Japanese travelers, 3 were returning from Indonesia, and 2 from Thailand or Malaysia. These results indicate that Aichi virus or a similar agent is endemic in Southeast Asian countries and is a cause of gastrointestinal symptoms in children in these areas or in Japanese travelers who visit there.

Adolescent↗
PubMed1995

Immunogenicity and reactogenicity of the component acellular pertussis vaccine produced by a combination of column purified pertussis toxin and filamentous haemagglutinin.

This is the report on a prospective, single blind, comparative study of a component acellular pertussis vaccine produced by a combination of detoxified, column purified pertussis toxin (PT) and filamentous hemagglutinin (FHA) combined with diphtheria and tetanus toxoids (DTcaP) and the traditional acellular pertussis vaccine produced with essentially the same method as described by Sato with DT (DTaP) of the same manufacturer. A total of 616 infants and children received DTcaP and a total of 289 received DTaP. In all age groups for both vaccines values of serum antibodies to PT and FHA after two doses of the vaccines were comparable to those of convalescent sera. Incidences of systemic and local reactions were, in general, not greatly different between DTcaP and DTaP recipients. In Japan the use of traditional acellular vaccines replaced whole cell vaccines in 1981. Protective antigens of Bordetella pertussis have now been specified and thus component vaccines have become theoretically possible. This is the first component vaccine which has been developed in Japan. Several other component vaccines are now under investigation in the world.

Antibodies, Bacterial↗
PubMed1994

Differentiation between wild and vaccine-derived strains of poliovirus by stringent microplate hybridization of PCR products.

Procedures for differentiation between wild and vaccine-derived strains of poliovirus are required, particularly in countries where wild and vaccine-related strains coexist. For this differentiation, we tested the method of Inouye and Hondo (S. Inouye and R. Hondo, Arch. Virol. 129:311-316, 1993) for discrimination of closely related viruses by using stringent microplate hybridization of PCR products. We used a pair of primers with enterovirus common sequences (between these primers there is a variable region for capsid proteins) for PCR using templates from wild and vaccine-derived poliovirus strains which were isolated in tissue culture and serotyped by neutralization assay. We also used the same primers for preparation of probes, which were labelled by incorporation of biotin-dUTP in the PCR, with the three original Sabin vaccine virus strains used as templates. The amplified DNAs from the isolates were immobilized on microplate wells and were then hybridized with the labelled probes. We found that, under the usual hybridization conditions, the Sabin vaccine virus strain probes hybridized with both wild and vaccine-derived viruses, but under stringent conditions, they reacted only with vaccine-derived viruses of the same serotype, clearly differentiating these from wild-type viruses.

Base Sequence↗
PubMed1993

Pulsed-field gel electrophoretic analysis of Campylobacter jejuni DNA for use in epidemiological studies.

The cleavage patterns of the genomic DNA of 42 clinical isolates of Campylobacter jejuni determined by pulsed-field gel electrophoresis (PFGE) were compared with their Lior and TCK serotypes. The fragment patterns of DNA obtained with SalI and SmaI restriction enzymes did not always accord with the corresponding serotypes but strains of the same serotype could be further divided into subtypes by their cleavage patterns. This PFGE method may prove useful for subclassifying C. jejuni.

Campylobacter jejuni↗
PubMed1993

Virological and serological studies on poliomyelitis in Karachi, Pakistan. I. Outbreaks in 1990-91.

Between October 1989 and September 1991, 124 cases of poliomyelitis visited the Department of Paediatrics, Civil Hospital Karachi, Pakistan. The majority of them were between 6 months and 2 years of age and the epidemics occurred during the hot seasons. The dominant serotype was poliovirus type 1 during the epidemic season in 1990 and type 2 in 1991. All the polioviruses isolated from the patients were wild-type. Virological studies also disclosed that enteroviruses other than polioviruses were prevalent among healthy children as well as among diarrheal and polio patients. A serological survey to elucidate the serological efficacy of oral polio vaccine (OPV) showed that: (i) in 112 unimmunized children, after disappearance of transplacental maternal antibody during early infancy, antibody prevalence increased gradually and > 80% of the children were seropositive against all three types of polioviruses at 5 years of age; (ii) in 201 children immunized with full doses of OPV in their infancy, the decrease in antibody titer during infancy was less and seroprevalence rose sharply afterwards: at 2 years of age, > 80% of them were seropositive against all three types of the virus. The rapid increase of seroprevalence might be the effect of OPV administration. However, the prevalence was lower than that in developed countries.

Antibodies, Viral↗
PubMed1993

Prevalence of newly isolated, cytopathic small round virus (Aichi strain) in Japan.

Cytopathic small round virus (Aichi strain), isolated from a patient with oyster-associated gastroenteritis, showed no reaction in the polymerase chain reaction method for enteroviruses or in the enzyme-linked immunosorbent assay (ELISA) for the five serotypes of astroviruses. Our ELISA was sensitive in detecting the Aichi strain antigen in stool samples, but there was no reaction in this ELISA with any non-Aichi strains of enteric viruses, with such origins as enterovirus, rotavirus, Norwalk virus, calicivirus, or astrovirus. In the ELISA, 13 of 47 stool samples from adult patients in five of nine oyster-associated gastroenteritis outbreaks were positive, but only 1 of 397 pediatric stool samples in Aichi Prefecture was positive. The prevalence rate for Aichi strain antibody was found to be 7.2% for persons aged 7 months to 4 years. The prevalence rate for antibody to Aichi strain increased with age, to about 80% in persons 35 years old. On the basis of the results of the present study, it was hypothesized that Aichi strain could be a new type of small round virus that mainly produces diarrhea in patients in the 15- to 34-year-old age group, 50 to 76% of whom possess neutralizing antibody.

Adolescent↗
PubMed1993

Measles and measles vaccine in Japan.

Before the introduction of measles vaccine in 1971, measles was a common and well-recognized disease in Japanese children. Seroepidemiological studies conducted before the general use of the vaccine disclosed that measles epidemics differed from community to community; in rural areas, epidemics appeared at intervals of several years with the accumulation of susceptibles, and in urban areas, measles was endemic affecting younger children. The measles vaccines developed in Japan showed excellent safety and efficacy in the clinical trials for general use. Since 1978 measles vaccines have been routinely given to children aged 12 months or older, and incidence of measles decreased dramatically. However, the vaccine acceptance rate has been only as high as 85% to 90% and small-scale outbreaks of measles have been observed periodically among unimmunized children: Measles is far from being eradicated in Japan. This is primarily due to the insufficient vaccine acceptance rate, and more efforts towards mobilization of parents to have their children vaccinated are now in progress.

Adolescent↗
PubMed1992

A 2-year survey of the prevalence of enteric viral infections in children compared with contamination in locally-harvested oysters.

We studied, for two years, the prevalence of indigenous human enteric viruses in wild oysters gathered each month from the bottom of Mikawa Bay, Aichi Prefecture, Japan. Viruses were detected periodically in 9 out of 54 oyster pools prepared by the acid or polyethylene glycol precipitation method although all these 9 pools met current national bacteriological safety standards. Since most of the serotypes of the enteric viruses detected in the oysters were identical with those of viruses isolated from sick children living in the area, it is suggested that contamination of enteric viruses in the oysters would depend on the prevalence of enteric viral infections in the local inhabitants.

Adenoviridae↗
PubMed1992

Genetic relatedness of hepatitis A virus strains recovered from different geographical regions.

A pairwise comparison of the nucleic acid sequence of 168 bases from 152 wild-type or unique cell culture-adapted strains of hepatitis A virus (HAV) revealed that HAV strains can be differentiated genetically into seven unique genotypes (I to VII). In general, the nucleotide sequence of viruses in different genotypes differs at 15 to 25% of positions within this segment of the genome. Viruses from four of the genotypes (I, II, III and VII) were recovered from cases of hepatitis A in humans, whereas viruses from the other three genotypes (IV, V and VI) were isolated only from simian species developing a hepatitis A-like illness during captivity. Among non-epidemiologically related human HAV strains, 81 were characterized as genotype I, and 19 as genotype III. Within each of these major genotypes, there were two distinct groups (subgenotypes), which differed in sequence at approximately 7.5% of base positions. Each genotype and subgenotype has a characteristic amino acid sequence in this region of the polyprotein, with the most divergent genotypes differing at 10 of 56 residues. Strains recovered from some geographical regions belonged to a common (endemic) genotype, whereas strains from other regions belonged to several, probably imported, genotypes. Thus, HAV strains recovered in North America were for the most part closely related at the nucleotide sequence level, whereas in other regions, such as Japan and Western Europe, HAV strains were derived from multiple genotypes or sub-genotypes. These data indicate that patterns of endemic transmission can be differentiated from situations in which infections are imported due to travel.

Amino Acid Sequence↗
PubMed1992

Adenovirus infection and specific secretory IgA responses in the intestine of infants.

We investigated adenovirus (Ad) infection of the intestine and Ad group-specific fecal IgA antibody responses in seven infants who were followed up from birth to 16 months to seven years of age. We isolated in tissue culture from fecal samples not only enteric Ad type 41 but also other Ads (types 2, 3, 5, 6, and 12). We also detected Ad antigens in the feces by ELISA at the times of infection with even non-enteric Ads, suggesting that a large amount of antigens were produced in the intestine. We found that repeated Ad infections with different serotypes were occurring and there were good fecal IgA antibody responses at each time. The infection seemed usually mild or asymptomatic: only one out of 23 occasions of the detected infections required hospitalization.

Adenovirus Infections, Human↗
PubMed1992

Epidemiological studies on measles in Karachi, Pakistan--mothers' knowledge, attitude and beliefs about measles and measles vaccine.

In order to gather information on the factors affecting the spread of measles vaccine in Pakistan, 287 mothers living in Karachi were interviewed concerning their knowledge, attitude and beliefs about measles and measles vaccine. Measles had been highly prevalent, mainly among infants between 9 and 18 months of age. The severity of the illness and the frequency of complications were well known and the importance of immunizations was well recognized. In traditional combined families grandparents had made the decision to take children for immunization, but many mothers had begun to feel that they were responsible for participation in the programme. The vaccine acceptance rate had increased sharply in recent years, primarily due to local health educators' activities and mass media such as TV programmes. The present findings confirm the importance of continuous effort toward promotion of primary health care by collaboration of motivated mothers and community health workers.

Adult↗
PubMed1992

[Family-acquired hepatitis A--prevalence of hepatitis A among the family in Aichi Prefecture, 1990].

We studied the transmission of hepatitis A virus (HAV) in 45 families, which members were diagnosed as hepatitis A in 8 hospitals in 1990. Feces and sera from 50 patients and their 126 family members were tested for HAV-specific antigen and IgM antibody by ELISA or polymerase chain reaction (PCR) technology. From the interval of the onset of hepatitis or detection of HAV antigen in feces, HAV transmission was recognized in 11 (24.4%) of 45 families. The transmission was found to be concerned with contacts of the children and that from children to parents was found in 4 families and the reverse in 2. HAV antigen was detected from feces of 4 family members before onset of icterus by ELISA and furthermore, 3 by PCR. It was indicated that these methods would be used to prevent the transmission in a family, day-care centers, or institutions for the mentally retarded.

Adolescent↗
PubMed1992

[Rapid diagnosis of influenza infection by PCR method--detection of influenza virus HA gene in throat swab].

We studied the detection of the HA gene of human influenza viruses in throat swabs obtained from the outbreaks of influenza in school children utilizing the polymerase chain reaction (PCR) method. Sensitivity and specificity of the PCR method was compared to conventional virus isolation using MDCK cells. Three pairs of primers for PCR in detecting the HA genes of AH1, AH3, and B influenza viruses showed both subtype and type specificity. The dilution experiments showed that influenza viruses, as few as 1.1-3.5 plaque-forming units per 50 microliters, were sufficient for the detection of HA genes by PCR method and the detection rate by PCR method was 2-3 fold higher than that by conventional method. Our results showed that the PCR method was a fast, sensitive and reliable method for the diagnosis of influenza infections.

Base Sequence↗