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Biomedical subjects

C Wasi

Publications and source records attributed to C Wasi.

At least 73 records · Page 4Linked to original sources
PubMed1992

Geographic diversity of human immunodeficiency virus type 1: serologic reactivity to env epitopes and relationship to neutralization.

The antibody recognition of the major neutralization epitopes of human immunodeficiency virus type 1 (HIV-1) in 829 HIV-1-seropositive subjects from North America (106), Europe (241), Africa (342), and Asia (100) was investigated. Peptides derived from diverse published V3 loop sequences were used as antigen, and serum reactivity was detected by sensitive ELISAs. Antibody binding to peptides derived from the V3 loop sequence of HIV-1 isolates varies considerably depending on the geographic origin of the antibody and is associated with neutralization titer against homologous isolates. Serotype reactivity to peptides may be a simple and rapid approach to investigation of HIV-1 env diversity worldwide and may assist the choice of immunogen for development of future AIDS vaccines.

Africa↗
PubMed1992

Immunoglobulin G antibody capture enzyme-linked immunosorbent assay: a versatile assay for detection of anti-human immunodeficiency virus type 1 and 2 antibodies in body fluids.

In tests on specimens of dried blood, saliva, and urine from 55 human immunodeficiency virus (HIV)-seropositive and 55 HIV-seronegative patients, an immunoglobulin G capture enzyme immunoassay for the detection of antibodies to HIV types 1 and 2, GACELISA, gave 109 of 110, 109 of 109, and 109 of 110 correct results, respectively. This performance, achieved in a laboratory previously unfamiliar with the assay, suggests that GACELISA is a useful new epidemiological tool for the study of HIV infection, equally applicable to all three kinds of specimen.

Body Fluids↗
PubMed1991

Human herpesvirus 6 (HHV-6) infection and exanthem subitum in Thailand.

Of 50 patients in Thailand suspected clinically of having exanthem, subitum, 31 (62%) were serodiagnosed as HHV-6 infection. Sixteen strains of HHV-6 from 31 patients (52%) whose antibody titers had converted during convalescence were isolated during the acute phase. The disease occurred in infants from 3 months to 1 year of age and most frequently at age 4-6 months. Antibody only to HHV-6 converted in 23 of 50 patients (46%), and seroconversion to HHV-6 and dengue virus was observed in 7 patients (14%), and to HHV-6 and Coxsackie B virus in 1 case (2%). In the 23 patients in whom seroconversion only to HHV-6 was observed, all had fever and rash which appeared after subsidence of the fever. Lymphadenopathy and relative lymphocytosis were recognized, associated with diarrhea, vomiting, running nose, cough and hepatomegaly. Febrile convulsions were seen in some cases. All patients recovered completely within a week.

Antibodies, Viral↗
PubMed1991

Molecular epidemiology of rotaviruses associated with pediatric diarrhea in Bangkok, Thailand.

Rotavirus diarrhea in 453 pediatric patients (29.8% of 1,518) was studied in greater Bangkok during 1985 to 1987. The disease persisted all year, increasing in incidence from August to January (30 to 50%). Polyacrylamide gel electrophoresis of rotavirus RNA from these patients and from an additional 46 patients of a 1982 to 1983 epidemic revealed 26 electropherotypes, 4 with short (S) and 22 with long (L) RNA profiles. Of the analyzed specimens, 85.5% were L forms. Only one or a few electropherotypes predominated in each epidemic, whereas others appeared sporadically at low frequencies. Shifts in the predominant electropherotypes were observed in every epidemic. Of these, 126 strains were tested for subgroup and serotype by monoclonal antibody enzyme immunoassay. Serotype 4 prevailed from 1982 to 1983, while serotype 1 was encountered more frequently than serotypes 2 and 4 from 1985 to 1987. A complete correlation was found between the electrophoretic migration of segments 10 and 11 and the serologically defined subgroup specificity. Distinct electropherotypes occurred within the same serotype, and strains with the identical electropherotype always showed the same serotype specificity. No specific electropherotype or serotype correlated with patient age. In this study, atypical rotaviruses and mixed infections with different rotaviruses were identified.

Adolescent↗
PubMed1991

Childhood diarrhoea in a low-income urban community in Bangkok: incidence, clinical features, and child caretaker's behaviours.

A one-year surveillance study of childhood diarrhoea in a low-income urban community in Bangkok revealed an annual incidence of 2.2 episodes per child among infants, and that the overall annual incidence among children under five years of age was 0.9 per child. Rotavirus, Salmonella and Campylobacter jejuni were common aetiologic agents. In children less than one year, diarrhoea was caused mostly by rotavirus and Salmonella. In 1-2 year old children, the major causative agent was rotavirus while E. coli, Campylobacter jejuni and Shigella were subsequent aetiologic agents. In grown up children (aged 2-5 years), the more common diarrhoeal pathogens were Shigella and E. coli. The clinical characteristics of diarrhoeal illness due to different pathogens were shown. The sources of drugs and the usage of available facilities in treating diarrhoea are also described. Caretakers treated childhood diarrhoea with ORS (53%), antibiotics (10%), and a combination of these in 15% of cases. These findings imply that the available facilities in this community can be better utilised to obtain more effective control of diarrhoeal morbidity and mortality.

Child, Preschool↗
PubMed1991

Follow-up of protective antibody level after post-exposure vaccination with purified tissue culture rabies vaccine (PCEC) small doses intradermally.

Twenty-nine vaccinees, 18 males, 11 females, aged 2-61 years (median 12 years) received PCEC intradermally for post-exposure prophylaxis during February to May 1989. Twenty-one cases received 4 sites of 0.1 ml ID on days 0, 3, 7 and 1 site ID on days 28 and 90. Four cases received 4 sites ID on days 0, 3, 7 and 1 site on days 14 and 28. The other 4 cases got the different schedules of ID by the poor compliance. Blood specimens were taken from these vaccinees at 2, 6 or 7, 9, 12 and 16 months after the initial dose. Neutralizing antibodies were measured by standard mouse neutralization test used WHO rabies antiserum as reference. All 65 tested sera showed positive neutralizing antibody. The GMT of antibodies at months 2, 6 or 7, 9, 12 and 16 were 17.68, 2.01, 1.56, 0.88 and 0.56 IU/ml respectively. Mild itching at injection sites was reported in 3 cases and low fever with malaise in 1 case.

Adolescent↗
PubMed1991

Epstein-Barr virus serological markers for nasopharyngeal carcinoma in Thailand.

The present study reports on the prevalence of specific IgA and IgG antibodies to EBV viral capsid antigen in nasopharyngeal carcinoma (NPC) patients with different histological types of carcinoma and their age-matched controls by the indirect immunofluorescence test, using the B-95-8 lymphoblastoid cell line as source of viral capsid antigen. EBV specific IgG was found in almost all the study cases, and antibody titers were significantly higher in the NPC patients than in non-cancer controls. GMT of anti-EBV IgG in NPC patients, patients with other malignant diseases, and those with non-malignant diseases were 371.5, 97.7 and 35.5, respectively. Anti-EBV specific IgA was more specific to NPC than was IgG, and was present in 86.5% (83 of 96) cases of NPC patients, 6.6% (2 of 30) of patients with other cancers, and 3.1% (3 of 97) cases of non-malignant diseases. A weak correlation between level of anti-EBV IgA in NPC patients was observed (r = 0.3). EBV IgA was found in all histological types of NPC, ie, WHO types 1, 2 and 3, but WHO type 1 was rare among NPC patients in Thailand. Use of anti-EBV IgA for monitoring cancer therapy is to be further investigated.

Adolescent↗
PubMed1990

Importance of salmonellae and Campylobacter jejuni in the etiology of diarrheal disease among children less than 5 years of age in a community in Bangkok, Thailand.

The etiology of diarrhea in children less than 5 years of age in a low-income housing project in Bangkok, Thailand, was determined over 1 year. Nontyphoidal salmonellae (13%), Campylobacter jejuni (12%), rotavirus (12%), enterotoxigenic Escherichia coli (7%), shigellae (6%), E. coli that hybridized with the enteropathogenic E. coli adherence factor probe (3%), and enteroinvasive E. coli (1%) were identified in 345 episodes of diarrhea in children less than 5 years of age. Salmonellae were identified in 17% and C. jejuni was identified in 15% of 54 children less than 6 months of age with diarrhea. Shigellae, enteroinvasive E. coli, enteropathogenic E. coli adherence factor, and enterotoxigenic E. coli were not isolated from children less than 6 months of age. Since salmonellae and C. jejuni were the most common bacterial pathogens identified in children less than 6 months of age, efforts to prevent transmission of salmonellae and campylobacter to young children should be a public health priority in Bangkok.

Campylobacter Infections↗
PubMed1990

Haemophilus influenzae and Streptococcus pneumoniae in children with acute respiratory infection.

The incidence of Haemophilus influenzae and Streptococcus pneumoniae in children with acute respiratory infection (ARI) under 5 years was carried out by throat swab culture, blood culture, body fluid or tissue culture in 688 patients from a community, 744 patients from a teaching hospital in Bangkok, 766 normal children from the community and 303 children from a hospital well baby clinic. H. influenzae was found in the throats of 15-20% of patients and in the throats of 4-6% of normal children (p less than 0.001 for both hospital and community patients). Only 12/332 strains (3.6%) of H. influenzae were type b. The rest of H. influenzae were non type b. The most common biotype of H. influenzae non type b was biotype II. S. pneumoniae was found in hospital patients in highly significant numbers compared to the controls (12% vs 4%). No significant difference was observed in strains from the community patients.

Bacterial Typing Techniques↗
PubMed1990

Behavior of urban based child caretakers in the home treatment of diarrheal diseases.

Behaviors of low income urban mothers and child caretakers in the treatment of childhood less than 5 year diarrhea were analysed from a surveillance study conducted between August 1988 and July 1989. Help seeking behaviors of mothers and caretakers for 412 episodes of child diarrhea were as follows: investigators 37.1%, drug stores 18.2%, wait and see or self treatment 17.0%, private clinics 12.6%, near by hospital 10.2%, and local health center 4.9%. Major treatment practices included ORT alone (54%) and ORT plus antibiotics and/or antidiarrheal drug (22%). Overall ORT usage was 76%. Twelve percent of diarrheal episodes no treatment was given to the children. Antimicrobials were believed to be essential in addition to ORT especially when diarrhea was associated with fever, vomiting and bloody stools. Thirty-six percent of invasive diarrhea cases (Shigella, Salmonella, Campylobacter) were treated with antibiotics. Only 18.2% of noninvasive diarrhea received antibiotics, most of this antibiotic use being in rotavirus diarrhea where vomiting and some fever are prominent. Availability of oral rehydration salts (ORS) and good experience with ORT were the key to the extensive use or ORT in this study. A surprisingly small number of mothers and child caretakers (4.9%) sought help from the local health center when their children had diarrhea.

Anti-Bacterial Agents↗
PubMed1989

Pre-exposure vaccination with purified chick embryo cell rabies vaccines in children.

Children who have close contact with rabid dogs, with a history of neither being bitten nor scratched nor licked on broken skin or on mucous membranes were given purified chick embryo rabies vaccine as pre-exposure prophylaxis. Thirteen children received 0.5 ml of the vaccine, while 12 children received 1 ml of the vaccine intramuscularly on days 0, 7 and 28. The rabies antibody level was measured by a standard mouse neutralization test. Before vaccination, all vaccinees had no detectable level of antibody to rabies. On day 14, all children had antibody levels higher than 0.5 IU/ml; the titer peaked from day 28 to day 56 and then was lower on day 90. Children of the 1 ml group had antibody levels higher than the 0.5 ml group, but there was no statistically significant difference. No serious reaction occurred. At 2-3 years of follow up, all children were doing well.

Adolescent↗
PubMed1989

Rabies and post-exposure prophylaxis in Thai children.

Thailand is an endemic area for rabies, with approximately 300 human deaths reported annually. More than half of the rabies patients are children under 14 years of age. This paper reports clinical data of paediatric rabies cases occurring from 1980 to 1986, and the protective efficacies of human diploid cell rabies vaccine (HDCV) and purified Vero cell rabies vaccine (PVRV) in children exposed to rabid animals. The analysis of 120 medical records revealed that rabies in children had incubation periods which ranged from less than fifteen days to more than three months, but generally between one to three months. The most frequent symptoms observed in the patients were hydrophobia, restlessness, fever, vomiting and aerophobia. Most of the rabid children admitted to hospital died within 24 hours. HDCV was administered to 50 children exposed to rabies with the cumulative dosages of 327 ml. All patients survived without serious adverse effects during a-two year follow-up. Mild reactions were seen in 1.5 percent (5/327 doses). Unfortunately, levels of rabies antibody in these vaccinees were not determined. Among another series of children exposed to rabid animals, comprising 27 individuals who received a total of 168 doses of PVRV, only mild local reactions were seen in 6 subjects. No rabies deaths were reported in 2 years of follow-up. The children who received PVRV either with or without human rabies immune globulin developed similar levels of rabies neutralizing (NT) antibody, which reached the high titers on day 30. At one year after the first dose of vaccination, all vaccinees still had NT antibody at titers higher than 0.5 IU/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Polyacrylamide gel electrophoresis and silver staining for detection of rotavirus in stools from diarrheic patients in Thailand.

Detection of rotavirus by polyacrylamide gel electrophoresis in combination with silver staining and by enzyme-linked immunosorbent assay showed 96.7% identical results in tests with 1,304 stool specimens from diarrheic patients. The polyacrylamide gel electrophoresis method can be modified to reduce cost and working time. Phenol extraction of stools, however, is essential in maintaining the sensitivity of the method.

Diarrhea↗