Pornsawan Amarapal

Mahidol University, Bangkok, Bangkok, Thailand

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Publications (7)4.25 Total impact

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    ABSTRACT: The human immunodeficiency virus Tat regulatory protein is essential for virus replication and for the efficient transcription of HIV-1 provirus, and in the pathogenesis of AIDS. The role of the tat gene was investigated in 300 samples. It was found that 71.7% were subtype CRF_01AE, 9.3% were subtype B, while 11.7 and 7.3% of them were cross-reactive and non-typeable, respectively. Moreover the results from peptide ELISA also showed that a low CD4 cell count was related to a low anti-Tat antibody (p < 0.05), which may be due to the progression of HIV-1, which can be found predominantly in AIDS patients. The results of nested PCR showed that the second Tat exon might also play a role in T-cell activation. Reverse transcription polymerase chain reaction (RT-PCR) was used to measure HIV-1 mRNA expression in PBMC. RT-PCR negative results were found mostly in the asymptomatic HIV-seropositive group (88%). HIV-1 mRNA expression was found to correlate with current immunologic status. The differences in Tat protein sequences from DNA sequencing between the patients who had anti-Tat antibody positive and anti-Tat antibody negative, were not significant (p > 0.05). These results suggested that the Tat amino acid sequences were conserved among each group of samples and did not change significantly compared with the consensus sequence in previous studies. Several factors make Tat an attractive target for vaccine design.
    The Southeast Asian journal of tropical medicine and public health 04/2005; 36(2):352-61. · 0.61 Impact Factor
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    ABSTRACT: The development of Isospora belli, a human coccidian parasite, was studied in different cell lines. Merozoites were observed in all kinds of cells, whereas sporogony was demonstrated only in Hct-8. This implied that not only the human cell line can be infected, but also some animal cell lines. Unizoites could be found in Vero cells. The merozoites were transferred to a new culture cell for three passages and maintained for two weeks, but no oocyst production was observed in any culture cells during cultivation.
    The Southeast Asian journal of tropical medicine and public health 01/2005; 35(4):796-800. · 0.61 Impact Factor
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    ABSTRACT: This study describes the development of Cryptosporidium parvum in MDCK, MA-104, Hep-2 and Vero cell lines. Differences in susceptibility, infectivity, and the methodology of excystation were determined. Various solutions were considered to determine the factors which enhanced the excystation (eg with and without sodium hypochlorite, trypsin or sodium taurocholate). It was shown that the sporozoites could be excysted in media either with or without trypsin and sodium taurocholate, but the number of sporozoites in the latter solution was less than the former one. Only oocysts digested by sodium hypochlorite and trypsin can enter the culture cells. Numerous meronts and oocysts were demonstrated and persisted for 9 days. Asexual stages were not observed in MA-104. Only few oocysts could be detected 1-3 days post-inoculation. There was a significant difference between the number of oocysts, which invaded MDCK, MA-104, and Hep-2 cells. MDCK gave the highest susceptibility to oocyst invasion among the three cell lines and asexual stages were also found. Among the 25 isolates, which had been cultivated, 23 isolates could infect MDCK and Hep-2. Only 2 isolates could not infect the MDCK cell. These 2 isolates could infect the Vero cell and yielded high numbers of trophozoites. Praziquantel (PZQ), doxycycline, and paromomycin (PRM) were tested on the infecting parasites. The drugs were added either with the inoculum or 24 hours after inoculation. None of them was effective, including PRM, which had been previously reported as effective.
    The Southeast Asian journal of tropical medicine and public health 10/2004; 35(3):540-6. · 0.61 Impact Factor
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    ABSTRACT: Fifty periodontitis patients and 30 healthy patients with oral cavities were selected from the Faculty of Dentistry, Mahidol University, Bangkok, Thailand, from March 2001 to November 2002. Their ages varied between 15 and 70 years. Among the periodontitis patients, specimens were collected from both disease and healthy sites. All samples were evaluated for the presence of CMV, HHV-6, and EBV-1 by nested PCR. Among the periodontitis patients, CMV was found in 34%, of which 8% were at the disease sites, 10% were at the healthy sites, and 16% were from both sites. EBV was not found in this group of the patients, while HHV-6 was found in 4%, at the disease sites only. CMV was found in one (3.3%) healthy control while HHV-6 and EBV-1 were not found. The depth of sample sites, various demographic and baseline characteristics eg sex, age, occupation and root planning were not associated with the presence of these viruses.
    The Southeast Asian journal of tropical medicine and public health 10/2004; 35(3):635-40. · 0.61 Impact Factor
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    ABSTRACT: Prevalence of CMV and toxoplasmosis antibodies were determined among normal newborn infants, suspected congenital neonates and pregnant women. Seropositive rates of CMV and toxoplasmosis were similar. Most of the pregnant women had CMV antibodies. The in-house ELISA for detection of Toxoplasma antibodies was developed and compared with the commercial kit with sensitivity and specificity of 90.47% and 96.74% respectively.
    The Southeast Asian journal of tropical medicine and public health 10/2001; 32(3):466-9. · 0.61 Impact Factor
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    ABSTRACT: Four hundred and forty-one blood and serum samples were collected during August to October 1998 from the blood donors at the blood bank of Rajvithi Hospital, Bangkok, Thailand. Their ages were varied between 18-55 years. All specimens were tested by immunostaining and ELISA methods. Forty-seven specimens (10.66%) gave positive results by immunostaining. Among these, 20 cases were seropositive and 27 cases were seronegative. The age group between 41-50 years had a high percentage of CMV infection as judged by the immunostaining method, more than the other age groups. By ELISA, 231 cases (52.38%) had positive IgG antibody to CMV, 42 cases (9.52%) were IgM antibody positive and 39 cases (8.84%) were positive for both IgG and IgM antibodies. The age groups between 36-40 years had a higher percentage of IgM antibody positives than the other age groups. Since the immunostaining method can detect early CMV infection, screening for the presence of antibodies alone is not enough to rule out CMV infection. Immunostaining along with ELISA detection of antibodies was useful for determining a decrease in CMV infection.
    The Southeast Asian journal of tropical medicine and public health 04/2001; 32(1):148-53. · 0.61 Impact Factor
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    ABSTRACT: Immunostaining was compared with PCR for diagnosis of congenital CMV infection. IgM and IgG antibody assays were also performed in parallel. Immunostaining gave sensitivity and specificity of 60% and 97% respectively. Correlations among immunostaining, PCR and the presence of IgM antibody was reported. Immunostaining can be used for early diagnosis of congenital CMV infection in parallel with detection of IgM antibody.
    The Southeast Asian journal of tropical medicine and public health 04/2001; 32(1):154-7. · 0.61 Impact Factor

Publication Stats

20 Citations
4.25 Total Impact Points

Institutions

  • 2005
    • Mahidol University
      • Department of Microbiology and Immunology
      Bangkok, Bangkok, Thailand