The prevalence and persistence of human parvovirus B19 infection in thalassemic patients

Human parvovirus B19 infection was studied in 60 thalassemic patients in Thailand. Seroprevalence, persistence of parvovirus B19 and their genotypes were identified in blood samples. Prevalence of anti-parvovirus B19 IgG and DNA found in thalassemic patients were 38% and 13%, respectively. Anti-parvovirus B19 IgM could be detected in 4% of these positive anti-parvovirus B19 IgG patients. The seroprevalence and parvovirus B19 DNA in patients with a history of blood transfusion were not significantly higher than those without such a history (44% vs. 34% and 20% vs. 9%, respectively). Phylogenetic analysis of NS1 nucleotide sequences of three parvovirus B19 samples revealed that they were parvovirus B19 genotype 1. They showed low genetic diversity from prototype (Au) strain. We concluded that acute and chronic persistent parvovirus B19 infection were found in the thalassemic Thai patients. Chronic persistence of parvovirus B19 infection might play important clinical role in thalassemic patients because of the high prevalence of parvovirus B19 DNA. Blood transfusion had no significant influence to increase the prevalence of parvovirus B19 infection in thalassemic patients.     

Shiga toxin- and enterotoxin-producing Escherichia coli isolated from subjects with bloody and nonbloody diarrhea in Bangkok,Thailand

A total of 314 stool samples collected from 92 subjects with bloody diarrhea, 119 subjects with non-bloody diarrhea and 103 normal subjects in Bangkok, Thailand, were investigated for the presence of Shiga toxin-producing Escherichia coli (STEC) and enterotoxin-producing E. coli (ETEC) by multiplex PCR assay. Virulence genes and cytotoxic effect to Vero cells of STEC were also determined. STEC (5 isolates) and ETEC (18 isolates) were detected in 3 and 14 subjects, respectively. Among subjects containing ETEC, only one person belonged to normal control group. The detected STEC included two isolates (serotypes O26:H(-) and O111:H(-)) of Shiga toxin type 1 (Stx1-only) STEC from a child with non-bloody diarrhea, two isolates (Stx1-Stx2 STEC and Stx1-only STEC) from an adult with bloody diarrhea, and one isolate of Stx1-Stx2v STEC (O157:H7) from normal child. Only Stx1-Stx2 STEC isolate was found to exhibit toxicity to Vero cells and carry hlyA gene. The intimin encoding gene locus eaeA was not detected in any isolate. These results indicate that most of STEC isolates in Thailand were low virulent.     

Cytotoxic T lymphocyte responses to vaccinia virus antigens but not HIV-1 subtype E envelope protein seen in HIV-1 seronegative Thais

The HIV-1 prime boost phase I/II vaccine trial using a recombinant canarypox vector, vCP1521, containing subtype E env (gp120), and subtype B env (gp41), gag and protease has started in Thailand. We have demonstrated that although 4 from 15 human immunodeficiency virus type 1 (HIV-1) seronegative Individuals showed cytotoxic T lymphocyte (CTL) responses to vaccinia virus antigens, none of them showed specific CTL responses to subtype E Env after in vitro stimulation. This preliminary study suggests that specific CTL responses to subtype E envelope detected in HIV-1 seronegative Individuals after vaccination should be considered as specific responses to the immunization.     

Application of ImageJ program to the enumeration of Orientia tsutsugamushi organisms cultured in vitro

The ImageJ program was applied to the enumeration of Orientia tsutsugamushi organisms in cell culture using indirect immunofluorescence assay (IFA). The highest correlation (r=0.984) was observed between manual counting methods and the ImageJ program (MaxEntropy threshold algorithm). This software-based methodology is cheaper, more standardised and better reproducible than a manual-based approach.     

Detection of new genotypes of Orientia tsutsugamushi infecting humans in Thailand.

PCR screening of blood specimens taken from 195 patients with serologically confirmed scrub typhus in three Thai provinces detected the 56-kDa protein-encoding gene from Orientia tsutsugamushi in ten (5%) patients. Significant genetic diversity was found among the ten amplicons, with nine new genotypes identified that were different from those found previously in Thailand. Phylogenetically, the ten sequences obtained in the present study and sequences from 71 strains characterised previously were distributed into several clusters that included the Karp, Gilliam, Kuroki, Saitama, Kawasaki and Kato clusters. Two of the new genotypes found in the present study clearly belonged to the Karp cluster. However, the other new genotypes formed three different clusters, including one cluster that appeared to be distant from all previously known clusters, and which may therefore be representative of a previously undescribed serotype. Other genotypes formed two other clusters that may also be associated with undescribed serotypes.     

Microsomal glutathione transferase 1 in anticancer drug resistance

Glutathione transferases (GSTs) are often upregulated in tumors and have been suggested to play an important role in multiple drug resistance in cancer chemotherapy. As a consequence GST-dependent pro-drugs and inhibitors are being developed. Little is known, however, on the potential role of membrane-bound GSTs in drug resistance despite the fact that detoxication of cytostatic drugs and upregulation in tumors has been demonstrated. Therefore, we have studied the involvement of membrane-bound microsomal GST1 (MGST1) in cellular resistance to anticancer drugs. As a tool we have developed a cell system utilizing MCF7 cells stably overexpressing MGST1. Here, we show for the first time that MGST1 can protect cells from several cytostatic drugs, chlorambucil, melphalan and cisplatin in an acute toxicity test (MTT assay) as well as a long-term colony forming efficiency cytotoxicity test. It is of note that these cells do not overexpress multidrug transporters, a prerequisite for protection with certain other GSTs investigated in this system. The cytostatic drugs used comprise both those that are known/predicted to be substrates as well as non-substrates. Thus, the mechanism most probably entails both direct detoxication and downstream protection of the cells from oxidative stress.     

Prevalence of HPV infection in hypopharyngeal and laryngeal squamous cell carcinoma at Thailand's largest tertiary referral center

Background

Following the well-established relationship between human papillomavirus (HPV) and cervical carcinoma, the carcinogenicity of this virus has also been confirmed in subsets of head and neck carcinoma (HNCA), but mainly in the oropharynx. Other subsites of HNCA with less known association to HPV have never been studied in Thailand. Accordingly, the aim of this study was to investigate the prevalence of HPV DNA in hypopharyngeal and laryngeal squamous cell carcinoma in Thai population.

Methods

This cross-sectional study included hypopharyngeal and laryngeal squamous cell carcinoma patients diagnosed and treated at the Department of Otorhinolaryngology, Siriraj Hospital during the September 2011–December 2013 study period. Presence of HPV genome was confirmed by polymerase chain reaction from pathologically-confirmed fresh specimens. Demographic data and risk factors of HPV infection were evaluated.

Results

Eighty patients were included, and 95% of those were male. Only one patient was noted with positive HPV-62 serotype. Most patients consumed tobacco and/or alcohol. Five patients had no risk factors for cancer development. Risk of HPV infection was evaluated by self-reporting questionnaire. The mean age of sexual debut was 20.17 years. Forty-eight patients had multiple sexual partners. Sixteen and seven patients had history of sexually transmitted disease infection and habitual oral sex contact, respectively.

Conclusion

There was no oncogenic HPV DNA detected within pathologic specimens of laryngeal and hypopharyngeal cancers in this study. Compared to rates reported from developed countries, the prevalence of HPV-related HNCA in Thailand is very low.

     

Effects of lifestyle modification on oxidized LDL,reactive oxygen species production and endothelial cell viability in patients with coronary artery disease

ObjectivesWe evaluated the effects of lifestyle modification (LM) on lipid profile, oxidative stress and serum-stimulated human coronary artery endothelial cell (HCAEC) viability in coronary artery disease (CAD) patients after 6 months.Design and methodsThirty patients with CAD were randomly assigned to LM intervention (n = 15) and usual care control (n = 15) groups. LM-intervened patients were instructed to consume low-fat, high-antioxidants and fiber diets. Moderate exercise and stress management were also advised. Group support to maintain patients' compliance was applied.ResultsSerum cholesterol, triglyceride, oxidized LDL and protein carbonyl were decreased in LM group. Serum triglyceride was increased in control group. HCAEC viability was increased, while intracellular reactive oxygen species was decreased, by serum from the LM group.ConclusionLM is capable of improving lipid profile, reducing oxidative stress and increasing HCAEC survival in the patients with CAD, hence lowering a risk for the future cardiovascular event.