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C Wasi

Publications and source records attributed to C Wasi.

At least 55 records · Page 3Linked to original sources
PubMed1996

V3 peptide enzyme immunoassay for serotyping HIV-1 infected pregnant Thais.

Previous molecular epidemiological studies show that at least 2 subtypes of HIV-1 circulate in Thailand. HIV-1 subtype B or Thai genotype B was associated with an early epidemic and was prevalent in intravenous drug users. Meanwhile, HIV-1 subtype E or Thai genotype A was becoming widespread among heterosexuals. We studied the HIV subtypes of 161 HIV-1 seropositive pregnant women. Of these, 143 pregnant patients (88.8%) tested positive for subtype E alone and 8 women (5.0%) had evidence of infection with subtype B alone. There was serologic evidence of infection with a mixture of subtypes in 7 women while the infecting subtype could not be identified in the remaining 3 women. This result agrees with previous information that subtype E predominates in Thai heterosexuals.

Female↗
PubMed1996

Lymphocyte immunophenotype reference ranges in healthy Thai adults: implications for management of HIV/AIDS in Thailand.

Lymphocyte immunophenotype reference ranges for T, B, and NK subsets were determined for healthy adult Thais in a multi-center study in Bangkok. Immunophenotyping was by flow cytometry using lysed whole blood. A standard protocol for flow cytometry instrumentation, reagents and quality control was used to minimize site differences and to facilitate comparison of the Thai reference values to those found for Caucasians in previous studies. Major differences were determined for CD3(T), CD4 (T helper/inducer) and CD16+56 (NK) lymphocyte percentages and CD4 lymphocyte absolute counts. Age trends and sex differences were also observed. Compared to Caucasians, Thais, particularly Thai males, had lower CD3 and CD4 T lymphocyte percentages and absolute numbers whereas the percentage of NK lymphocytes was higher. Heterogeneity attributed to biological variation of CD4 T lymphocyte but not other immunophenotype subset distributions was also observed in a well defined geographic population. This study demonstrates the importance of ethnicity, age, sex and possibly environment as factors that influence distribution characteristics of normal lymphocyte immunophenotype reference values. These observations have important implications for the use of lymphocyte subsets-particularly CD3+ CD4+ T lymphocyte measurements as applied to HIV disease staging, AIDS definition and the overall clinical management of HIV/AIDS in Thailand.

Adult↗
PubMed1996

Acute hemorrhagic conjunctivitis outbreak in Thailand, 1992.

The 260 cases of acute hemorrhagic conjunctivitis seen at Siriraj Hospital during October to December, 1992 were studied. Evidence of coxsackie virus A24 variant (CA24v) infections was demonstrated in 76.8% of 95 cases. The isolation rates from conjunctival swabs and throat swabs were 68.2% and 32.8%, respectively. A four-fold rising titer of neutralizing antibody was shown in 59.5% of 42 cases. The disease was characterized by a short incubation period, sudden onset, a mild and self-limited course within 5 days without ocular sequelae. Lacrimation, swelling lida, itching, foreign body sensation and periorbital pain were common features with bilateral involvement in the majority of cases. Approximately 48% of eyes had a mucopurulent discharge. Preauricular lymphadenopathy, keratitis and subconjunctival hemorrhage were observed in 16.2%, 12.6%, and 10.1% of affected eyes, respectively. Respiratory disturbances accompanied the eye signs in some cases. Only one case developed neurological complications: facial palsy was observed for three months without recovery.

Adolescent↗
PubMed1995

Determination of HIV-1 subtypes in injecting drug users in Bangkok, Thailand, using peptide-binding enzyme immunoassay and heteroduplex mobility assay: evidence of increasing infection with HIV-1 subtype E.

OBJECTIVES: To evaluate the sensitivity and specificity of peptide-binding enzyme immunoassay (PEIA) and heteroduplex mobility assay (HMA) for the determination of HIV-1 subtypes B and E; to determine the proportions of infections due to subtypes B and E over time; and to generate data on DNA sequences of the C2-V3 region of the env genes. METHODS: HIV-1 subtyping was conducted by PEIA and HMA on blood specimens obtained from 97 injecting drug users (IDU) infected with HIV between 1988 and 1993. Genetic sequencing was performed on 84 specimens. RESULTS: Both laboratory methods were highly sensitive and specific for the determination of HIV-1 subtypes B and E. The two tests were complementary; samples which could not be typed by HMA were correctly typed by PEIA and vice versa. While subtype B accounted for 80.4% (78 out of 97) of infections overall, the proportion of new infections due to subtype E increased from 2.6% (one out of 38) in 1988-1989 to 25.6% (11 out of 43) in 1990-1991, and to 43.8% (seven out of 16) in 1992-1993 (chi 2 for linear trend, P < 0.001). CONCLUSIONS: HMA and PEIA are practical, sensitive and specific laboratory methods for the determination of HIV-1 subtypes in Thailand, and may be useful in other geographic areas to define the molecular epidemiology of the global HIV-1 pandemic. Data suggest that the proportion subtype E infections have increased among Bangkok IDU from 1988 through 1993.

Adult↗
PubMed1995

The evolving molecular epidemiology of HIV-1 envelope subtypes in injecting drug users in Bangkok, Thailand: implications for HIV vaccine trials.

OBJECTIVE: To genetically characterize HIV-1 strains in injecting drug users (IDU) in Bangkok, Thailand in 1994, and compare these with strains found earlier in Thai IDU; such information is essential for HIV-1 vaccine development and evaluation. METHODS: Peripheral blood mononuclear cells were collected from 84 IDU attending 14 drug treatment clinics in Bangkok in 1994. DNA was amplified using a nested polymerase chain reaction (PCR) procedure and sequenced directly (without cloning) from the PCR products. The V3 and flanking regions (345 nucleotides) of the env gene were analyzed using a neighbor-joining tree. RESULTS: Only one (1%) strain was a typical subtype B virus, 69 (82%) were genetically distinct subtype B' viruses (Thai B), and 14 (17%) were subtype E strains (Thai A). Persons with recently acquired infection were more likely to have subtype E viruses (P < 0.001) than those in our 1991 survey, who were more likely to have subtype B' viruses. Pairwise intra-subtype differences within subtypes E and B' were 5.3 and 4.3%, respectively, compared with 3.4 and 3.5% among strains collected in 1991 in Thailand. CONCLUSION: The genetic diversity within subtypes B' and E in Thailand and the proportion of new infections due to subtype E viruses among Bangkok IDU are increasing significantly. These data highlight the importance of monitoring the molecular epidemiology of HIV-1 in populations being considered for HIV-1 vaccine trials.

AIDS Vaccines↗
PubMed1995

Serological response to respiratory syncytial virus infection in pediatric patients with a comparison to immunofluorescence and virus isolation.

The serological response to respiratory syncytial virus (RSV) in 125 pediatric patients hospitalized with acute lower respiratory infection was investigated by enzyme linked immunosorbent assay (ELISA) for specific immunoglobulin (Ig) A, IgG, and IgM and complement fixation (CF) test. By ELISA, a 4-fold rise in IgG titre in paired sera was most commonly found, followed by a rise in IgA and IgM titres. Investigation by ELISA and CF leads to the suggestion that major CF activity against RSV antigens resides in the IgG and not the IgA and IgM classes. No case with CF activity failed to be diagnosed by ELISA. The youngest infant who could develop seroconversion was one month old, nevertheless two children older than two years could not. When the three diagnostic methods were compared, ELISA serology was the most sensitive followed by indirect immunofluorescence (IIF) for antigen detection and virus isolation, respectively, ELISA could diagnose RSV infection in 45% of the study cases, whereas IIF and virus isolation only diagnosed 26% and 14%, respectively. Half of the cases was diagnosed by all of the three methods together.

Child, Preschool↗
PubMed1995

Seroprevalence of human herpesvirus 6 and 7 infections in the Thai population.

Seroprevalence of human herpesvirus 6 (HHV-6) and 7 (HHV-7) was estimated in the Thai population using indirect immunofluorescence assay to determine serum antibodies to HHV-6 and HHV-7. A total of 333 serum samples obtained from umbilical cord blood and venous blood of healthy persons at Siriraj Hospital and Krabi Hospital during 1990-1993 were investigated. Of 73 infants aged 0-1 month, 73% and 78% were found tob e positive for HHV-6 and HHV-7 antibodies, respectively. Antibody to HHV-6 was detected in age groups 2-3 months (38%), 4-5 months (14%), 6 months (44%), 7-11 months (66%), 1-2 year (84%), 3-4 years (82%), 5-9 years (83%), 10-19 years (83%), 20-29 years (80%), 30-39 years (67%), and over 40 years (58%), respectively. This positive rates of HHV-7 antibody in age groups 2-3 months, 4-5 months, 6 months, 7-11 months, 1-2 years, 3-4 years, 5-9 years, 10-19 years, 21-29 years, 30-39 years, and over 40 years were 50%, 21%, 10%, 37%, 47%, 82%, 75%, 72%, 72%, 67%, and 67%, respectively. At 6 months of age as the starting time of infections, 34% (14/41) and 9% (3/41) of infants had presumed primary infections of HHV-6 and HHV-7, respectively. In the follow-up study, 53% (20/38) of children were infected with HHV-6 prior to HHV-7 and only 5% vice versa. Eighty-four percent of children had acquired antibody to HHV-6 by 1-2 years old while 82% of children had acquired antibody to HHV-7 by 3-4 years old. These results suggest that HHV-6 and HHV-7 are prevalent viruses in the Thai population. The infections of both viruses begin at 6 months of age. However, infection of HHV-7 in most children begins later. The data also provided evidence that antigenic distinction between HHV-6 and HHV-7 existed with a limited cross-reactivity in an antibody test. The antibody responses to HHV-6 and HHV-7 occurred independently.

Adolescent↗
PubMed1994

A simplified and economical intradermal regimen of purified chick embryo cell rabies vaccine for postexposure prophylaxis.

Healthy volunteers were randomized to receive either intradermal purified chick embryo cell rabies vaccine (PCEC) alone (0.1 ml at each of two sites on days 0, 3 and 7, and at one site on days 28 and 90) (n = 81), or intradermal PCEC with one dose of human rabies immunoglobulin (HRIG) intramuscularly at 20 IU kg-1 on day 0 (n = 52). Neutralizing antibody (NAB) was detectable in every volunteer, in both groups, from day 14 up to day 365. The peak NAB occurred on day 28 in both groups. No significant suppressive effects of HRIG on NAB response were observed. Side-effects were mild and self-limiting. These preliminary results suggest that this simplified low-dose intradermal regimen could be an alternative schedule in rabies postexposure prophylaxis, resulting in lower overall costs.

Administration, Cutaneous↗
PubMed1994

Syncytium-inducing and non-syncytium-inducing capacity of human immunodeficiency virus type 1 subtypes other than B: phenotypic and genotypic characteristics. WHO Network for HIV Isolation and Characterization.

Positively charged amino acid substitutions at positions 11 and 25 within the loop of the third variable region (V3) of HIV-1 subtype B envelope have been shown to be associated with the syncytium-inducing (SI) phenotype of the virus. The present study was designed to examine SI and NSI-associated V3 mutations in HIV-1 subtypes other than B. HIV-1 RNA was isolated from 53 virus stocks and 26 homologous plasma samples from 53 recently infected individuals from Brazil, Rwanda, Thailand, and Uganda. The C2-V3 region of the viral envelope was converted to cDNA, amplified, and sequenced. Of 53 primary virus stock samples 49 were biologically phenotyped through measurement of the syncytium-inducing capacity in MT-2 cells (to differentiate between SI and NSI phenotypes). In addition, after passage of primary isolates through PHA stimulated donor PBMC, the replication capacity was determined in U937-2, CEM, MT-2, and Jurkat-tat cell lines (to differentiate rapid/high and slow/low phenotypes). According to the sequence analysis 9 (17.0%) of the viruses belonged to subtype A, 15 (28.3%) to subtype B, 1 (1.9%) to subtype C, 13 (24.5%) to subtype D, and 15 (28.3%) to subtype E. Sequence analysis of virus RNA, obtained from 26 homologous plasma samples, confirmed the homogeneity of sequence populations in plasma compared to primary virus isolates. Of the 49 viruses tested 12 had the SI phenotype, 5 were confirmed to be rapid/high, and 4 appeared to be slow/low pattern 3 replicating. Of 49, 29 had the NSI phenotype, 24 were confirmed to be slow/low pattern 1 or 2, and 3 appeared to be slow/low pattern 3 replicating. Analysis of mutations at V3 loop amino acid positions 11 and 25 revealed that 10/12 (83.3%) of the SI viruses had SI-associated V3 mutations and that 28/29 (96.6%) of the NSI viruses lacked these mutations. V3 loop heterogeneity, length polymorphism, and a high number of positively charged amino acid substitutions were most frequently found among subtype D variants. These results indicate that both the phenotypic distinction between SI and NSI viruses and the association of biological phenotype with V3 mutations is present among HIV-1 subtypes other than B.

Adult↗
PubMed1994

Was the 1988 HIV epidemic among Bangkok's injecting drug users a common source outbreak?

OBJECTIVE: To describe and understand the genesis of the explosive 1988 HIV epidemic among Thai injecting drug users (IDU) in Bangkok. DESIGN: Two cross-sectional HIV seroprevalence sample surveys (SP-1 and SP-2) of drug users, including IDU at various stages of treatment. SP-1, a 10-week estimate of prevalence, was conducted by the Bangkok Metropolitan Administration (BMA) in their detoxification clinics from 5 January to 7 March 1988. SP-2 estimated prevalence in 1 week, 12-15 September 1988, in the same 18 BMA clinics. Both surveys included an administered questionnaire that gathered demographic and behavioral information. METHODS: Analysis of HIV prevalence by clinic in both SP-1 and SP-2, and the relationships between demographic data, behavioral variables, arrest history and HIV positivity in SP-1. RESULTS: Data from individual clinics in SP-1 show significant increases in HIV prevalence among IDU sampled from early February 1988. Of IDU sampled in five 'early' clinics before 9 February, 2% were positive; in the 13 'late' clinics sampled from 9 February until 7 March, 27% were positive. By September 1988, however, the early and late clinics were no longer heterogeneous for HIV prevalence. For current IDU, HIV-positivity was associated with the sharing of injection equipment in SP-1 [odds ratio (OR), 1.82; 95% confidence limits (CL), 1.31-2.53] and recent jail or prison stay (OR, 2.15; 95% CL, 1.18-3.98). CONCLUSIONS: The behavioral factors associated with the HIV epidemic among Bangkok's IDU are similar to those described elsewhere. The monthly incidence of 5% from February to September 1988 suggests extensive needle or injection equipment sharing networks among IDU in Bangkok. Additionally, the pattern of HIV-positivity by detoxification clinic over time in early 1988, and then in September 1988 is consistent with a relationship to the prison amnesty of early December 1987. Shortly after that date, an undisclosed number of former IDU, a substantial number of whom were still injecting, and may have become HIV-positive while in custody, returned to resume injecting within existing drug-using networks throughout Bangkok and elsewhere in Thailand.

Adolescent↗
PubMed1994

Flow cytometric three-color determination of CD4 T-lymphocytes on blood specimens from AIDS patients who have a large number of contaminating non-lymphocytes.

A three-color flow cytometric determination of CD4 T-lymphocytes on whole blood specimens from AIDS patients which contain a high proportion of non-lymphocyte elements is described. Peripheral blood cells were stained by a three-color method using monoclonal antibodies conjugated respectively with fluorescein isothiocyanate (FITC)-CD3, phycoerythrin (PE)-CD4 and peridinin chlorophyll protein (PerCP)-CD45. CD45 stains all leukocytes with the highest fluorescence expression of CD45 antigen in lymphocytes. By combining light scatter with CD45 in the fluorescence 3 (FL3) channel, a light scattering window can be drawn to include almost all bright CD45 lymphocytes. This live gate of lymphocytes was then acquired and analysed simultaneously using other irrelevant two-color (FITC/PE) antibodies of CD3 and CD4 in the FITC and PE channels, respectively. This method is easy and straightforward, and gives successful analysis of CD4 T-lymphocytes in AIDS blood specimens contaminated with an unusually large number of non-lymphocytic cells.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Incidence of Mycoplasma pneumoniae, Chlamydia trachomatis, and viral infections in pneumonia cases under six months of age, Bangkok, Thailand.

The incidence of infections by Mycoplasma pneumoniae, Chlamydia trachomatis and respiratory viruses was investigated in 76 pneumonic patients aged under 6 months who attended Ramathibodi and Siriraj Hospitals in Bangkok during two study periods. M. pneumoniae infection was not found in any case from either hospital by serological diagnosis. By the isolation method, C. trachomatis infection was found in 7(16.7%) of 42 patients from Ramathibodi Hospital and 5(21.7%) of 23 patients from Siriraj Hospital with the average male:female ratio of 2.6:1; and 91.7% of the infected cases were under 3 months old. Laboratory diagnosis of respiratory virus infection was performed by indirect immunofluorescence (IIF), isolation, and by antibody detection. Data from Ramathibodi Hospital showed that 11 (24.4%), 4 (8.9%), 3 (6.7%) of the 45 patients were infected by respiratory syncytial virus (RSV), adenoviruses, parainfluenza virus type 3, and some other viruses, respectively; infection rates of 10 (32.3%), 4 (12.9%), 1 (3.2%) and 1 (3.2%) by those viruses respectively, were observed in the 31 patients from Siriraj Hospital.

Chlamydia Infections↗
PubMed1994

Detection of human cytomegalovirus in urine of infants by polymerase chain reaction.

Polymerase chain reaction (PCR), viral isolation and serological methods were used to diagnose HCMV infection in infants. Specimens of urine and clotted blood were collected from suspected cases of congenital or HCMV infection who attended the Pediatric Clinic, Siriraj Hospital. Prevalence of HCMV infection was found in 3 per cent of infants aged under 14 days and increased to 48 per cent in infants aged over 14 days. PCR was the most sensitive technique, it could detect HCMV infection in 29 per cent of the study infants, whereas, detection rate by isolation was 17 per cent and by specific IgM ELISA was 15 per cent. Sensitivity and specificity of PCR compared with isolation and/or serology were 93 per cent and 96 per cent, respectively. Detection of HCMV in urine by PCR can be used as a sensitive and rapid test for diagnosis of HCMV infection in infants.

Base Sequence↗
PubMed1993

Detection of Epstein-Barr virus DNA and HHV-6 DNA in tissue biopsies from patients with nasopharyngeal carcinoma by polymerase chain reaction.

A total of 34 tissue biopsies were collected from nasopharyngeal carcinoma (NPC) patients and 5 controls with non-NPC. Extracted DNA from tissue biopsies were analyzed for presence of specific gene sequences to EBV type A and type B, and HHV-6 by polymerase chain reaction (PCR). The different sequences of EBV type A and B were parts from the highly divergent forms of the EBV nuclear antigen 2 (EBNA 2). The PCR amplified products for EBNA 2A and EBNA 2B were 115 and 119 base pairs respectively whereas that of HHV-6 DNA was 776 base pairs. The results demonstrated that EBV DNA was detected in 32 of 34 cases (94.1%): 28 (82.3%) with type A, 2 (5.9%) with type B, and 2 (5.9%) with both types. EBV DNA of type A could be detected 1 (20%) of 5 controls. HHV-6 DNA was in 5 of 34 samples (14.7%) whereas HHV-6 DNA was not detectable in biopsy tissues from controls. The results show that in the NPC patient group, A type of EBV is predominant. Detection of HHV-6 DNA in patients group only might be resulted from reactivation of a latent infection or association with EBV-induction of NPC.

Base Sequence↗
PubMed1993

The abbreviated 2-1-1 schedule of purified chick embryo cell rabies vaccination for rabies postexposure treatment.

During August 1988 to January 1990, the immunogenicity and safety of purified chick embryo cell rabies vaccine (PCEC) given by the conventional and abbreviated regimens in 82 vaccinees moderately to severely exposed to laboratory proven rabid animals were studied. The 16 vaccinees received PCEC six doses as conventional schedule on days 0, 3, 7, 14, 28 and 90, the 11 vaccinees received six doses of PCEC plus human rabies immune globulin (HRIG) on day 0. The 29 vaccinees received an abbreviated schedule of PCEC as two doses on day 0, one dose each on days 7 and 21 and the 26 cases received PCEC abbreviated schedule plus HRIG on day 0. The kinetics of the neutralizing antibodies on days 0, 7, 14, 28, 56, 180 and 365 were studied for comparative purpose. All vaccinees had high antibody levels from day 14 which last longer than a year and were safe after one year follow up. The adverse reactions of the vaccine were mild and self-limited.

Adolescent↗
PubMed1993

Prevalence of IgA specific antibodies to Epstein-Barr virus capsid and early antigens in nasopharyngeal carcinoma.

Ninety-one patients with nasopharyngeal carcinoma (NPC), and 164 age-matched healthy controls were tested for presence of IgA antibodies to Epstein-Barr virus capsid antigen (VCA) and early antigen (EA) in their sera by indirect ELISA using "EBViral DETECT" commercial test kit. IgA anti-VCA was found in 76 (83.5%) of NPC patients and 16 (9.8%) of the controls. Meanwhile, IgA anti-EA was found in 72 (79.1%) of NPC patients and 21 (12.8%) of the controls. In a parallel study by indirect immunofluorescence test (IIF), IgA anti-VCA was found in 77 of 91 (84.6%) NPC patients and 22 of 142 (15.5%) controls. The prevalence rates of anti-VCA as screened by ELISA and IIF were very similar suggesting that neither one of the two tests can be used alternatively depending on the purpose and facilities in each individual laboratory. IgA antibodies to VCA and EA were more prevalence in NPC patients than those in the controls, the finding which again supported the association between EBV and NPC as was suggested in many other reports.

Adult↗
PubMed1993

Prevalence of human herpesvirus 6 in Thai people and its correlation with human immunodeficiency virus type 1 infection.

Human herpesvirus 6 (HHV-6) is a human herpesvirus isolated from patients with various lymphoproliferative disorders and acquired immunodeficiency syndrome (AIDS). The prevalence of HHV-6 infection and its correlation as a cofactor in pathogenicity of HIV infection was investigated in serum samples from 365 healthy volunteers at various age groups, 50 persons at risk for HIV-1 infection, and 90 HIV-1 seropositive individuals. Sera were screened and titrated for antibodies against HHV-6 by a standard indirect immunofluorescence assay on an acetone fixed HHV-6 infected HSB2 cells. The data show high prevalence of HHV-6 in Thailand (71.7%) and the infection is acquired early in life. Prevalence of anti-HHV-6 IgG antibodies was not strikingly different among people at risk for HIV infection, asymptomatic HIV-1 infected cases, and aged-matched controls with low risk for HIV-1 infection. The AIDS cases showed high titers of anti-HHV-6 IgG antibody and high rates for presence of anti-HHV-6 IgM antibody (33.3%) which suggests higher prevalence of HHV-6 infection by either reactivation of an earlier HHV-6 infection or a new primary infection.

Acquired Immunodeficiency Syndrome↗