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Biomedical subjects

P Phanuphak

Publications and source records attributed to P Phanuphak.

At least 19 recordsLinked to original sources
PubMed1995

HIV-1 subtypes and male-to-female transmission in Thailand.

We examined the risk factors for heterosexual transmission of HIV in a case-control study of couples in Thailand. 90 HIV-positive men and their regular sex partners were enrolled at the immune clinic, Chulalongkorn Hospital, where 92% of male index cases had HIV-1 serotype A (subtype E). Most index cases had acquired HIV through sexual intercourse. 95 couples were enrolled at 15 detoxification clinics, where 79% of them had HIV-1 serotype B (subtype B). Most men had acquired HIV through injecting drug use (IDU).

Case-Control Studies↗
PubMed1994

Knowledge, attitudes and behaviour among HIV-positive and HIV-negative clients of a confidential HIV counselling and testing centre in Thailand.

OBJECTIVE: To describe the clients, operation and impact of an Asian public HIV counselling and testing centre. DESIGN AND SETTING: Analysis of samples from clients attending the Thai Red Cross Anonymous Clinic (TRC-AC) in Bangkok, Thailand in 1993. SUBJECTS: HIV-positive and HIV-negative consecutive clients (250 of each). MAIN OUTCOME MEASURES: HIV seroprevalence rates, knowledge, attitudes and behaviour. RESULTS: Overall HIV-1 prevalence was 16%; 13% in men and 24% in women. Reasons for requesting an HIV test were high-risk behaviour (21%), feeling unwell (20%), checking a previous HIV test result (18%), a planned marriage or new relationship (10%), and planning a baby (5%). Heterosexual risk behaviour was reported by 85% of clients, while in each case only 1% reported male homosexual or intravenous drug use risk behaviour. Factors associated with HIV infection on univariate analysis included a history of sexually transmitted disease, not using condoms, a low level of education and salary, and being female. Knowledge about HIV transmission risks and AIDS prevention measures was good, and most clients expressed a caring attitude towards people with HIV and AIDS. A former negative HIV test result was associated with higher levels of condom use, and most clients expressed the intention to reduce their HIV risk behaviour in response to a positive or negative HIV test result (more so if positive). CONCLUSIONS: Our study demonstrates the demand for and the feasibility of confidential HIV counseling and testing services in Thailand and illustrates the value of these services in achieving behaviour changes. Such services should be considered as an additional approach for reducing HIV transmission in Asia, especially in areas with high HIV seroprevalence rates.

Adult↗
PubMed1994

Standardization of methacholine inhalation challenge by a reservoir method.

Standardization of methacholine inhalation challenge (MIC) by a reservoir method was performed at Respiratory Unit, Chulalongkorn Hospital. One hundred subjects, including 20 non-smoking healthy subjects, 20 patients with isolated chronic cough, 20 patients with isolated allergic rhinitis, 20 patients with stable chronic obstructive bronchitis, and 20 patients with mild bronchial asthma, were scheduled to perform the test. The aerosolized methacholine was produced by an atomized nebulizer of the Provocation test I (Pari-Starnberg) and the aerosol was kept in a reservoir bag. It was inhaled by each subject via a slow vital capacity. Increasing concentrations of methacholine (0, 0.5, 1, 5, 10, and 25 mg/ml were used. None of the healthy subjects had increased bronchial hyperresponsiveness (BHR). Sixty percent of patients with chronic cough, 60% of patients with allergic rhinitis, 95% of patients with chronic obstructive bronchitis, and 100% of patients with asthma were found to be positive in the MIC tests. No serious effect from methacholine during and after the tests was found. It was concluded that MIC can be easily performed by a reservoir with reproducible results to demonstrate BHR.

Adult↗
PubMed1994

Should travellers in rabies endemic areas receive pre-exposure rabies immunization?

A questionnaire survey was conducted in 1,882 foreign travellers, 74% of which were Europeans, after being in Thailand for an average of 17 days, about the history of potential rabies exposure during their visits. Dog bite and dog lick were experienced in 1.3% and 8.9% of the travellers respectively. The exposed individuals tended to stay in Thailand longer and the incidents occurred mainly in cities rather than in the rural areas. Thirty-one (1.6%) of all travellers had a history of rabies vaccination, 9 as a result of dog bite or dog lick in Thailand whereas the remaining 22 had already received the vaccine prior to coming to Thailand. Such high prevalences of potential rabies exposure and rabies vaccination may justify the inclusion of rabies vaccine into the multiple vaccination program for travellers to rabies endemic countries. This was favoured by over half of the travellers interviewed.

Adult↗
PubMed1993

Strong immunogenicity of a multicomponent peptide vaccine developed with the branched lysine oligopeptide method for human immunodeficiency virus infection.

We synthesized one V3 peptide each from HTLV-IIIB, Thai A and Thai B, conjugating them to the T cell epitope of the env region, and we also synthesized a p17 protein peptide of the gag region (HGP-30). These peptides were then coupled to 8-lysine copolymers using N-succinimidyl maleimido carboxylate (M(r) = ca 60,000). We designated this the branched lysine oligopeptide method. The large peptide complexes constructed from these four macromolecular peptides were used with aluminium hydroxide or complete Freund's adjuvant to immunize mice and rabbits four times. ELISA assay showed high titres of anti-peptide antibodies to each V3 loop peptide and the HGP-30 peptide. Strong inhibition of CD4+ dependent cell fusion was obtained with these antisera when IIIB, Thai A and Thai B strains of the human immunodeficiency virus (HIV) were used. Strong anti-fusion inhibition was also observed with two other HIV strains. In addition, an increase of the anti-HIV effect was observed when we used sera obtained by multicomponent vaccine immunization. The same kind of inhibition was also observed in p24 assay systems using these immunized antisera. Activation of IL-2 production in lymphocytes was observed in mice immunized with this vaccine. These results suggest that immunization with macromolecular peptide complexes can result in strong immunogenicity towards HIV-1.

AIDS Vaccines↗
PubMed1992

Genetic variants of HIV-1 in Thailand.

Serosurveys conducted prior to 1988 indicated a very low level of HIV-1 infection in Thailand, even among high-risk groups. The Ministry of Health has reported a dramatic increase in HIV-1 infection during the last three years. The geographic and demographic distribution of the epidemic is broad, involving multiple provinces and risk groups. Foci of higher incidence and prevalence have been noted in the urban center of Bangkok and in the northern provinces of Chiang Mai and Chiang Rai. Here we report the results of genetic characterization of 16 HIV-1 isolates from Thailand using a combination of polymerase chain reaction (PCR) typing and DNA sequencing. The complete sequence of gp160 (env) of five isolates, partial env sequence of six additional isolates, and the gag gene of two isolates were determined. Two highly distinct HIV-1 variants were found. One variant resembled those prevalent in North America and Europe; five of the isolates were of this type. The remaining eleven isolates were very similar to one another and represented a variant unlike any previously described. Phylogenetic tree analysis of complete env and gag genes placed the two variants on widely separated branches. Protein sequence comparisons indicate both general and specific features that distinguish the Northern Thailand variant both from the Bangkok variant and from virtually all previously sequenced HIV-1 isolates. A simple PCR test for distinguishing the two variants has been developed for use in epidemiologic surveys.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Clinical correlation of the immunological markers of HIV infection in individuals from Thailand.

OBJECTIVE: To evaluate the usefulness of T-cell subsets, beta-microglobulin (B2M), p24 antigen and anti-p24 antibodies as differentiating and prognostic markers in HIV-infected Thai patients. DESIGN: Sixty-one HIV-infected patients in various stages of disease (six AIDS, three AIDS-related complex, 34 persistent generalized lymphadenopathy and 18 HIV-asymptomatic) were followed prospectively for 2 years. Patients were examined and immunological markers assessed every 6 months at least. Any HIV-related complications were treated symptomatically and clinical staging was re-evaluated at each visit. Due to financial constraints, none of the patients were given antiretroviral drugs. METHODS: T-cell subsets were enumerated by indirect immunofluorescence using OKT4 or OKT8 for T-helper and T-suppressor cells, respectively. beta 2M and p24 antigen were quantified by enzyme-linked immunosorbent assay and anti-p24 antibodies were by immunoblot assay. RESULTS: Our preliminary study revealed that the decrease in CD4+ T-cells or anti-p24 titre and the increase in p24 antigen or beta 2M correlated well with disease staging, as defined by the Centers for Disease Control. Absolute number and percentage of CD4+ T-cells, absolute number of CD8+ T-cells, beta 2M level and p24 antigen and anti-p24 antibody levels at entry could be used as reliable prognostic markers for HIV progression. The combination of p24 antigen with the number of CD4+ T-cells substantially increased the prognostic value, compared with either used alone. CONCLUSIONS: The annual rate of clinical progression from asymptomatic to symptomatic HIV infection in our study was 6.8%. The results we obtained in this preliminary study may be used as baseline data for planning future therapeutic interventions in Asian patients.

Adolescent↗
PubMed1992

Cells with natural killer activity in human rabies.

Cytotoxic lymphocyte function in 13 patients with rabies was studied by counting the number of CD56 cells and assessing natural killer (NK) cell activity. There was no significant difference in the number of killer cells between rabies patients and 31 normal controls (P greater than 0.05). Two of six non-fatal encephalitic patients due to causes other than rabies had reduced CD56 numbers. Base-line NK cell responses versus K562 cell targets did not differ among the normal control and rabies groups (P greater than 0.05). Study of the non-rabies encephalitis group showed heterogeneous results with wide variation. Significant enhancement of NK activity was seen in four rabies patients and in 10 normal control subjects tested after interferon-alpha (IFN-alpha) and IL-2. None of the four patients with encephalitis due to causes other than rabies showed such enhancement. Our results suggest that NK cells of rabies patients are not fully stimulated and that this might contribute to the virulence of rabies. The cause of this phenomenon remains unknown.

Adolescent↗
PubMed1991

Immune response to rabies vaccine in Thai dogs: a preliminary report.

Serum neutralizing antibody to rabies virus was determined in previously unvaccinated Thai pet dogs after receiving one subcutaneous dose of inactivated tissue culture rabies vaccine (Rabdomun, Coopers Animal Health Company, Germany, 4.55 IU ml-1 potency). Geometric mean titres on days 14, 30, 60, 180 and 360 were 2.14, 2.30, 0.45, 0.14 and 0.05 IU ml-1, respectively, by the rapid immunofluorescent focus inhibition test. Titres of neutralizing antibody to rabies virus did not correlate with the age of the dog at the time of vaccination or with the presence or absence of anaemia or blood parasites. Six out of 50 (12%), 11 out of 43 (25.6%) and 13 out of 31 (42%) dogs had no detectable rabies antibody in serum 60, 180 and 360 days, respectively, after vaccination. Three of these antibody-negative dogs were given another dose of vaccine. Antibody reappeared on day 14 but rapidly declined within 60 days. These data suggest that one dose of tissue culture vaccine in dogs by the subcutaneous route of injection is not adequate to maintain rabies neutralizing antibody in serum for 1 year.

Animals↗
PubMed1991

Comparison of the sensitivity of various anti-HIV tests in early seroconversion sera.

Paired sera from 4 patients with proven HIV infection whose initial specimens obtained 14-51 days earlier were indeterminate were simultaneously retested with 7 screening anti-HIV test kits and the immunoblot assay. The study aimed to evaluate the sensitivity of various new and old anti-HIV screening tests. The test kits evaluated were 4 ELISA test kits from Wellcome (Wellcozyme), Organon (Vironostika anti-HTLV-III), Pasteur (Rapid Elavia) and Diagnostic Biotechnology (DB, HIV-1 ELISA), 2 rapid tests based on microfiltration enzyme immunoassay procedure from Rapport (SUDS) and Disease Detection International (SeroCard), and 1 particle agglutination (PA) test (Serodia-HIV). Immunoblot strips from Diagnostic Biotechnology (HIV-1 Western blot) were used to confirm the HIV infection in these serum specimens. Out of the 4 initial serum specimens tested, all were positive by PA, 2 by SUDS, Wellcome and Pasteur, 1 by SeroCard and DB, and none by Organon. When tested by immunoblot, 1 was negative (i.e., completely without any bands) whereas 3 were indeterminate (i.e., 1 with very weak band for p18, 1 with weak band for p24, 1 with very weak band for gp160. All repeat specimens obtained 14-51 days later (mean 32.5 +/- 16 days) were positive by all screening tests as well as immunoblot. Therefore, with these 4 early seroconversion sera, the sensitivity of the PA was 100%, that of SUDS, Wellcome and pasteur was 50%, of that SeroCard and DB was 25%, and Organon, 0%. None of these sera was considered positive by immunoblot.

AIDS Serodiagnosis↗
PubMed1990

What happens if intradermal injections of rabies vaccine are partially or entirely injected subcutaneously?

Reported are the results of a study with the Thai Red Cross two-site intradermal purified Vero-cell rabies vaccine (PVRV) schedule that was deliberately injected into subcutaneous tissue. The 44 healthy nonimmune Thai adults who were enrolled in the study were randomly assigned to the following groups and given PVRV as shown: group A (two intradermal injections on days 0, 3, and 7); group B (one intradermal and one subcutaneous injection on days 0, 3, and 7); and group C (two subcutaneous injections on days 0, 3, and 7). Neutralizing antirabies antibody titres were determined on day 14 using the rapid fluorescent focus inhibition test. High rabies antibody titres were obtained for all three groups. These results suggest that the economical and safe Thai Red Cross intradermal PVRV regimen could be used in selected general health care facilities.

Adolescent↗
PubMed1989

Regional distribution of rabies viral antigen in central nervous system of human encephalitic and paralytic rabies.

We studied the distribution of rabies viral antigen in the brain and spinal cord of 7 patients with rabies by immunohistochemical techniques. Four patients presented with encephalitis, the remaining 3 had paralysis. Neither the rabies viral antigen distribution nor inflammation paralleled clinical presentations. Patients who had survival times of 7 days or less (4/7) had a greater amount of antigen-positive neurons in brainstem and spinal cord regardless of the clinical type. Neuroglial cells were also found to contain rabies antigen. Our findings suggest that virus localization may not account for the difference in clinical manifestations.

Adolescent↗
PubMed1989

Immunoenhancement with combined rabies and aluminium-adjuvanted tetanus vaccines.

The effect of combining tetanus toxoid in the same syringe with purified Vero cell rabies vaccine (PVRV) was investigated in the 2-1-1 regimen of PVRV. The 2-1-1 regimen alone was as immunogenic as the five-dose regimen, while saving one dose of vaccine and two clinic visits. When aluminium hydroxide-adsorbed tetanus toxoid was used to dissolve PVRV on days 0 (one of the two doses) and 21, the anti-rabies antibody was significantly increased. Aluminium-free tetanus toxoid was ineffective, suggesting that immunoenhancement was due to aluminium adjuvant. In addition, anti-tetanus antibody was unaffected and the side-effects were not increased by such mixing.

Adjuvants, Immunologic↗