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Biomedical subjects

S Isomura

Publications and source records attributed to S Isomura.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Establishment of hybridoma cells with natural killer(NK)-like activity against syngenic tumor cells.

The 4D1D4 hybridoma cells were derived from the fusion of spleen cells from BALB/c nude mice with NS-1 mouse myeloma cells. The surface phenotypes of 4D1D4 hybridoma cells were Thy-1.2+, L3T4 (CD4)-, Lyt-2 (CD8)-, Asialo GM1+ and p-55 interleukin-2 (IL-2) receptor (CD25)-. This phenotypic pattern was consistent with the surface phenotype of NK cells. The 4D1D4 cells showed the definite killer activity against a syngenic tumor cell line, RL male-1, but not against an allogenic YAC-1 line. The killer activity of the 4D1D4 cells was not affected by the addition of exogenous IL-2. It was, therefore, suggested that 4D1D4 cells might be representative of resting NK cells with expression of no functional IL-2 receptors. The hybridoma technology might be useful for establishment of the cloned NK cells.

Animals↗
PubMed1992

[Rapid detection of motile Salmonella in chicken meat by the 1-2 Test].

The 1-2 Test (BioControl) is an enrichment culture/immuno-diffusion assay for detecting Salmonella in foods by use of poly-H-antibodies. The performance of the 1-2 Test was compared with that of the traditional culture method on 85 chicken meat samples. The results were as follows: The detection frequency of Salmonella by the 1-2 Test 24-hour assay (28/85, 32.9%) was greater than that by the 8-hour assay (16/85, 18.8%) and almost equal to that by the traditional method (26/85, 30.6%). The 8-hour assay gave a 46.2% sensitivity and 93.2% specificity. The 24-hour assay gave an 84.6% sensitivity and 89.8% specificity. Detection appeared to show some influence from the number of Salmonella, number of viable cells (SPC) and coliform groups. Differences in serotypes of Salmonella detected by the 1-2 Test and the traditional methods were also observed. Although there were some differing results between the 1-2 Test and the traditional method, this system appears to be useful for detecting Salmonella in foods, since results can be obtained at least 24 hours earlier than by the conventional procedures.

Animals↗
PubMed1992

The low rate of HIV infection in Japanese homosexual and bisexual men: an analysis of HIV seroprevalence and behavioural risk factors.

OBJECTIVE: To assess the seroprevalence of HIV-1 infection in homosexual and bisexual men in Nagoya City, Japan. DESIGN: A prospective study ongoing since April 1986. METHODS: Nine hundred and thirty-eight serum samples were collected from 531 participants in August 1990 in an anonymous, confidential testing programme. A self-administered questionnaire was completed and all participants anonymized by a code number. Interviews were conducted and HIV-antibody test results given by telephone, except for the positive test results, which were given in person and counselling offered. RESULTS: Two out of the 531 participants (0.38%) were found to be seropositive for HIV-1, although the seroprevalences of sexually transmitted diseases, including hepatitis B, syphilis, chlamydia infection and amoebiasis, were remarkably high. A small number of participants had had sexual contact with individuals from countries where HIV infection rates are high. No patient had had a recent episode of intravenous drug use. Numbers of male sexual partners were decreasing and unsafe sexual practices, such as anal intercourse without condom use, were also decreasing. CONCLUSIONS: The apparent low-risk behaviour of the men studied here (low levels of sexual contact with foreigners, absence of intravenous drug use, decreasing numbers of sexual partners and unsafe sexual practices) may explain the low prevalence of HIV infection.

Adolescent↗
PubMed1979

Echocardiographic evaluation of right ventricular anterior wall motion in the Wolff-Parkinson-White syndrome.

Echocardiographic motions of right ventricular anterior wall (RVAW) were investigated in 71 patients with Wolff-Parkinson-White (WPW) syndrome. According to the criteria of Rosenbaum et al the electrocardiograms were classified as type A in 35 patients and type B in 36. Sixteen type B patients exhibited abnormal RVAW motion, which was characterized by an early onset of the posterior movement before S1 andl also by a premature peak formation before S2. A small step or hump nearly coincident with S1 was observed in 10 of these 16 patients. These findings seem to suggest that both contraction and relaxation of RVAW begin earlier than normal due to anterior right ventricular pre-excitation. RVAW motion was normal in all of type A patients. Echocardiographic investigation of RVAW motion appears to be useful in non-invasive estimation of the site of pre-excitation, especially in type B WPW patients.

Adolescent↗
PubMed1978

Acute infantile gastroenteritis caused by rotavirus in Japan.

We had an outbreak of acute infantile gastroenteritis accompanied by milky-white stool (called Hakuri in Japanese) during the winters of 1976 and 1977. Stool specimens collected from 72 cases of Hakuri were studied by negative-staining electron microscopy. Rotavirus was detected with a very high frequency (89%). Rotavirus obtained from one of the patients was isolated and passaged in cultures of primary human embryonic kidney cells. Viral antigens could be detected in the cytoplasm of the cells by indirect immuno-fluorescence. The fluorescence-positive cells increased in number with repeated passage. Serum anti-viral activities in 11 patients were titrated by indirect immuno-fluorescence, using the cells infected with the passaged rotavirus. All 11 patients developed IgM responses in the convalescent phase. However, in 4 of the 11 patients, no IgG responses were detected even 2--3 weeks after the onset of illness. The reinfection which has occasionally be seen in our country may be related to these poor IgG responses.

Acute Disease↗
PubMed1978

An epidemiological study of subacute sclerosing panencephalitis in Japan, 1976.

The National Registry for subacute sclerosing panencephalitis (SSPE) of Japan was established in 1976 at the Research Institute for Microbial Diseases, Osaka University, under the auspices of the Ministry of Health and Welfare. By March 1977, forty five clinically confirmed cases of SSPE were reported to the Registry, with onset of symptoms occurring between 1966 and 1976. Histories of measles were available in 42 of these cases. Thirty nine patients with known histories had measles prior to onset of SSPE and 3 had no history of measles illness. Twenty eight (71.7%) of the 39 patients had measles before the age of 2 years. All cases were 1 to 14 years old at the time of onset of SSPE and the mean interval between measles and SSPE was 6.1 years. One of the 3 cases with no history of measles was a recipient of measles killed vaccine, but no case of SSPE was reported among recipients of measles live, attenuated vaccine.

Adolescent↗
PubMed1977

Protective efficacy of vaccination in children in four episodes of natural varicella and zoster in the ward.

It was previously reported that a live varicella vaccine (Oka strain) has been developed and that the immediate vaccination of hospitalized children was effective for prevention of spread of varicella in a ward. Six to nine months later, there were four separate episodes of varicella and zoster in the same ward. Eighteen children (11 with nephrotic syndrome, 6 with nephritis, and 1 with hepatitis) with no history of varicella were inoculated with a live vaccine before or immediately after admittance or occurence of the varicella and zoster cases. Twelve of them had been receiving steroid therapy and 15 of the 18 were found to be seronegative by complement fixation and neutralization tests before the vaccination. All of them became seropositive after vaccination without any clinical symptoms. The longest period between vaccination and exposure was nine months. None of the vaccinees exhibited varicella symptoms after exposure. Serological follow-up of ten vaccinated children was done, and booster responses were observed in some of them after exposure. These results suggest that the live vaccine affords immunity to the recipients. If hospitalized children are vaccinated before or immediately after exposure, isolation of the patient is unnecessary.

Adolescent↗
PubMed1977

[Effects of electrical stimulus upon L-strain cells. (Part 2)--Response of the cells to alternative current prior to cultivation (author's transl)].

In order to examine the effects of voltage, current time and frequency of the alternative current on cell multiplication and morphology during initial stage of cell cultivation, alternative currents of varying intensity were applied to the L-strain cells in the tissue culture medium, i.e. YLH solution supplemented with 5% bovine serum which was considered as an electrolyte solution. The following results were obtained: 1) The rates of cell multiplication depended on the frequency (0.01 Hz-10 KHz), when voltage and current time were kept constant. In particular, they were remarkably depressed in the low frequency range. In a certain frequency range, a maximum value of the rates of cell multiplication was recorded. It was considered that there is certainly a least inhibitive frequency range in the rates of cell multiplication. 2) The lower and the shorter the voltage and current time were, the lower were the frequency level at the threshold of marked inhibition of the rates of cell multiplication brought. 3) An arbitrary equation for the relationship between the rates of cell multiplication and frequency was determined: The rates of cell multiplication upon cell multiplication were proportional to (A + log F), where A was a constant value and F was the applied frequency. According to the equation above, the depression upon cell multiplication was calculated, when the values of voltage and current time were given. 4) It was found that the results of the rates of cell multiplication were parallel to the results of the morphological observations. It was presumed that the main factor governing cell multiplication during application of the alternative current was due to change of the compositions of medium which was electrolyzed.

Animals↗