Mutational analyses of K-ras exon 2 in Thailand colorectal cancer tissue samples.

Objective: The main purpose of this study was to elucidate the genotype of K-ras gene in Thailand colorectal cancer tissue samples, especially in exon 2, which has never before been reported. Methods: 106 patients’ samples in formalin fixed paraffin embedded tissue blocks were investigated in this study. DNA was extracted and PCR was performed by using primers specific for the K-ras gene at exon 2. Direct sequencing was performed in a Genetic Analyser ABI3130 with specific software. Results: The mutation of K-ras exon 2 gene in Thailand colorectal cancer samples accounted for 37.7% of the total. The most common mutation found in this series was the G"A transition which accounted for 70%. Conclusion: The incidence of K-ras exon 2 mutation in Thailand colorectal cancer samples was remarkedly similar to previous reports.

Antiproliferative effect of cucurbitacin B extracted from trichosanthes cucumerina L. on human cancer cell lines.

Objective: To determine the antiproliferative effect of cucurbitacin B extracted from Trichosanthes cucumerina L. on human cancer cell lines. Methods: Two human lung non-small cell (adenocarcinoma) cancer cell lines i.e., LK87, and QG95, two human colon adenocarcinoma cell lines i.e., HCT15, and HT29, including one renal cancer cell line, A498, and one pancreatic cancer cell line, NOR-P, were used in this study. The viability of cells was assessed by using WST-8 which is based on detection of LDH released from damaged cells and reacts with WST-8 to form a yellow color. Cells were treated with the compound at various concentration from 1 through 100 µg/ml. Results: The ED50 values (effective doses that are required for 50% inhibition growth of tumor cells) of the compound on human cancer cell lines ranged from approximately 69 µg/ml in HCT15 cells up to 231 µg/ml in QG95 cells. The inhibition of proliferation of this compound on these human cancer cell lines was observed to be in a dose dependent manner. Conclusion: It could be concluded from this observation that this compound has a modest direct toxic effect to these cell lines with the highest toxic effect on human colon cancer cells.

Comparison of conventional manual methods with the ADVIA 120 automated method for counting of red and white blood cells in cerebrospinal fluid.

Objective: To evaluate the correlation and agreement of erythrocyte and leukocytes count in cerebrospinal fluid (CSF) among two different manual methods and automated method. Methods: We evaluated the correlations and agreements of the CSF RBC counts, WBC counts and WBC differential counts between two manual methods and automated method by using the ADVIA 120 CSF assay. Results: We studied 83 CSF specimens in all methods. Absolute cell counts showed a high correlation and agreement between methods, with correlation coefficient (rs) for all absolute counts of more than 0.89 and intraclass correlation (ICC) more than 0.9. The correlation and agreement of WBC differential counts from CSF specimens which had more than 20 WBCs/µL were also evaluated, which revealed good results only for polymorphonuclear cells, neutrophils and lymphocytes (rs = 0.796, 0.835 and 0.779, respectively and ICC = 0.954, 0.899 and 0.907, respectively). When WBC counts more than 5 cells/µL in automated method were used as a cut-off point, the sensitivity is 100% but specificity is very low (60.87%). The cut-off point of 5 WBCs/µL for manual method and 11 WBCs/µL for automated method gave the highest agreement (Kappa 0.874, sensitivity 91.43% and specificity 95.65%). Conclusion: The ADVIA 120 CSF assay provide a useful and efficient method for excluding the normal CSF specimens at cut-off 5 WBCs/µL.

Lymphocyte and NK cell subpopulations in HIV seronegative Thais.

Lymphocyte subpopulations, i.e. T, B and natural killer (NK) cells including NK cell subsets which express CD16 molecules (with or without co-expression of CD56 molecules) and NK cell subsets which express CD56 molecules (with or without co-expression of CD16 molecules) were enumerated by two color-flow cytometry in a total of 125 HIV seronegative Thai adults. The study demonstrated relatively low CD4 counts in the subjects, i.e. 26.3% of them had a CD4 count of less than 500 cells/microl. In contrast, their NK cell counts were relatively high. Statistical analyses of the percentage values showed that females had significantly higher CD3 (total T cells), but lower NK cell counts as compared to males (p < 0.05). Regarding age variation, an increase of 1.1% of CD4 cells per decade was seen. It was roughly estimated that about 86% of NK cells harbored both CD16 and CD56 molecules. Collective data from several studies including the present one suggest that high NK cell counts may be a compensation for low CD4 cell counts in Mongoloid people. Thus, the role of NK cells in the defense cascade against viral infections, especially human immunodeficiency virus infections deserves further investigation.

Peripheral blood type 1 and type 2 T cells in Thai children with atopic diseases.

Several studies have shown that decreased IFN γ or increased IL 4 secretion by Tcells are associated with allergy and these can predict the development of atopic diseases. We compared the production of IL 4 and IFN γ in atopic Thai children with appropriate controls. Twenty five atopic patients and twenty four non-atopic subjects were enrolled. Production of IFN γ and IL 4 by peripheral blood mononuclear leukocytes was measured under stimulating conditions (phorbol myristate acetate). The atopic group comprised 6 atopic asthmatics and 19 allergic rhinitis patients. The results showed no significant difference in the IFN γ/ IL 4 ratio between atopic asthmatics, and allergic rhinitis patients and controls. However, the difference between asthmatics and controls was larger than between the other groups. In this study, a nonsignificant trend of overproduction of IL 4 compared with IFN γ is shown only in asthmatic children as compared to those with rhinitis and controls.