A study to implement early diagnosis of HIV infection in infants born to infected mothers

A protocol for detecting HIV DNA from specimens collected on filter papers and the effect of storage temperatures on determination of HIV DNA from dried blood spots has been developed and optimized. Blood specimens collected from HIV-1 infected and normal persons were spotted onto blood collection cards (Whatman BFC 180). The HIV DNA was extracted by phenol-chloroform-isoamyl alcohol and was detected for C2V4 of HIV-1 env by nested polymerase chain reaction (nested PCR). One set was stored at -20 degrees C for 14 weeks, another at 37 degrees C for 1 week and then kept at -20 degrees C for 13 weeks and a third set at 25 degrees C for I week and then -20 degrees C for 13 weeks. The dried blood spots from each set were detected for the HIV DNA every 2 weeks for 14 weeks. The C2V4 region of HIV env DNA was determined from small amounts of the dried blood collected on the filter papers. The nested PCR procedure could detect as few as 5 copies of HIV proviral DNA, and HIV DNA could be detected from specimens with viral loads of 2x 10(4) copies/ml. HIV DNA could be detected from specimens collected at all temperatures tested for at least 14 weeks. Therefore, laboratory diagnosis of HIV infection can be done by PCR on dried blood spots. These techniques will be useful as a tool for studying the epidemiology of HIV infection among populations of interest such as mother to child infection using newborn screening specimens.     

Phenylketonuria detected by the neonatal screening program in Thailand

Neonatal screening for phenylketonuria (PKU) was introduced as a pilot project in Thailand from 1992--1995, and mass screening was started in 1996 by the Department of Medical Sciences, Ministry of Public Health. Blood samples were collected by heelprick on filter paper either at 48 hours of life or before discharge from the hospital. Elevated blood phenylalanine was identified by screening with the Guthrie method, then followed by the fluorometric method: All infants with a phenylalanine level equal to or greater than 4 mg/dl were recalled and retested using the fluorometric method and confirmed by plasma amino acid analysis and urinary pterins for tetrahydrobiopterin deficiency. A total of 1,062,676 newborns were screened from October 1992--March 2001, with 5 cases confirmed with PKU. The incidence was 1 in 212,535. All patients have been treated with low phenylalanine diet. The results of this study confirm the benefit of early detection and treatment of PKU through the screening program.     

Leeaoside,a new megastigmane diglycoside from the leaves of <Emphasis Type="Italic">Leea thorelii</Emphasis> Gagnep

A new megastigmane diglycoside, leeaoside, was isolated along with four known compounds; benzyl O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside, quercetin 3-O-α-l-rhamnopyranoside, myricetin 3-O-α-l-rhamnopyranoside and citroside A from the leaves of Leea thorelli. The structure determinations were based on physical data and spectroscopic evidence.     

Stability of genomic DNA in dried blood spots stored on filter paper

The stability of DNA in dried blood samples obtained from the neonatal screening program in Thailand was retrospectively studied in order to determine the conditions necessary for the long term storage of samples for DNA banking. Specimens from 1991 to 2001, which had been kept in the ambient conditions at the Department of Medical Science, Ministry of Public Health, Thailand, were randomly sampled and used for the study. Genomic DNA was extracted from the samples and DNA fragments of the PAX8 and beta-globin genes were amplified by PCR to determine DNA stability. The study showed that 255-bp and 674-bp fragments of the PAX8 gene could be amplified from all the samples. The DNA fragment of 1,039 bp of the beta-globin gene could be detected in all of the samples for the years 1993 to 2001, but only in seven and five out of the ten studied samples for each of the years 1991 and 1992, respectively. Our study shows that genomic DNA is stable in dried blood stored on filter paper at ambient tropical conditions for at least 11 years. However, DNA quality for amplification of larger DNA fragments decreased when the specimens were stored for longer than 10 years.     

Pediatric brain tumor cancer stem cells: cell cycle dynamics, DNA repair, and etoposide extrusion

Reliable model systems are needed to elucidate the role cancer stem cells (CSCs) play in pediatric brain tumor drug resistance. The majority of studies to date have focused on clinically distinct adult tumors and restricted tumor types. Here, the CSC component of 7 newly established primary pediatric cell lines (2 ependymomas, 2 medulloblastomas, 2 gliomas, and a CNS primitive neuroectodermal tumor) was thoroughly characterized. Comparison of DNA copy number with the original corresponding tumor demonstrated that genomic changes present in the original tumor, typical of that particular tumor type, were retained in culture. In each case, the CSC component was approximately 3-4-fold enriched in neurosphere culture compared with monolayer culture, and a higher capacity for multilineage differentiation was observed for neurosphere-derived cells. DNA content profiles of neurosphere-derived cells expressing the CSC marker nestin demonstrated the presence of cells in all phases of the cell cycle, indicating that not all CSCs are quiescent. Furthermore, neurosphere-derived cells demonstrated an increased resistance to etoposide compared with monolayer-derived cells, having lower initial DNA damage, potentially due to a combination of increased drug extrusion by ATP-binding cassette multidrug transporters and enhanced rates of DNA repair. Finally, orthotopic xenograft models reflecting the tumor of origin were established from these cell lines. In summary, these cell lines and the approach taken provide a robust model system that can be used to develop our understanding of the biology of CSCs in pediatric brain tumors and other cancer types and to preclinically test therapeutic agents.     

Cell death gene expression profile: role of RIPK2 in dengue virus-mediated apoptosis

Dengue virus (DENV) is a major emerging arthropod-borne pathogen, which infects individuals in both subtropical and tropical regions. Patients with DENV infection exhibit evidence of hepatocyte injury. However, the mechanisms of hepatocyte injury are unclear. Therefore we examined the expression of cell death genes during DENV-infection of HepG2 cells using real-time PCR arrays. The expression changes were consistent with activation of apoptosis and autophagy. Expression of the up-regulated genes, including RIPK2, HRK, TGF-β, PERK, and LC3B, was confirmed by quantitative real-time PCR. RIPK2 belongs to the receptor-interacting protein family of serine/threonine protein kinases, which is a crucial mediator of multiple stress responses that leads to the activation of caspase, NF-κB and MAP kinases including JNK and p38. RIPK2 activity is inhibited by the p38 MAPK pathway inhibitor SB203580. The effect of SB203580 on RIPK2 expression and DENV-induced apoptosis was tested in DENV-infected HepG2 cells. The inhibition of RIPK2 expression by SB203580 significantly reduced apoptosis. SB203580 also significantly reduced DENV capsid protein (DENVC)-mediated apoptosis. Suppression of endogenous RIPK2 in DENV-infected HepG2 cells by small interfering RNA (siRNA) significantly decreased apoptosis suggesting for the first time that RIPK2 plays a role in DENV-mediated apoptosis.     

Impaired interaction of alpha-haemoglobin-stabilising protein with alpha-globin termination mutant in a yeast two-hybrid system

Alpha-thalassaemia caused by alpha-globin gene termination codon mutations (alphaT-globin) has been explained by their inherent mRNA instability and by oxidative damage arising from the presence of membrane-bound alphaT-globin chains. To better understand the latter phenomenon, a yeast two-hybrid system was used to assay the interaction between alphaT-globin and its molecular chaperone, alpha-haemoglobin-stabilising protein (AHSP) and impaired binding of alphaT-globin with AHSP compared with alpha(wild-type)-globin was observed.     

An Evaluation of Phosphate Buffer Saline as an Alternative Liquid-Based Medium for HPV DNA Detection

Objective: HPV detection has been proposed as part of the co-testing which improves the sensitivity of cervical screening. However, the commercially liquid-based medium adds cost in low-resource areas. This study aimed to evaluate the performance of ice-cold phosphate buffer saline (PBS) for HPV detection. Methods: HPV DNA from SiHa cells (with 1-2 copies of HPV16 per cell) preserved in ice-cold PBS or PreserveCyt solution at different time points (24, 36, 48, 72, 120 and 168 h) was tested in triplicate using Cobas 4800. The threshold cycle (Ct) values of both solutions were compared. An estimated false negative rate of PBS was also assessed by using the difference in Ct values between both solutions (∆Ct) and Ct values of HPV16-positive PreserveCyt clinical samples (Ctsample) at corresponding time points. Samples with a (Ctsample+∆Ct) value > 40.5 (the cutoff of HPV16 DNA by Cobas 4800) were considered as false negativity. Results: The Ct values of HPV16 DNA of SiHa cells collected in PBS were higher than PreserveCyt ranging from 0.43 to 2.36 cycles depending on incubation times. There was no significant difference at 24, 72, 120, and 168 h.  However, the Ct values were statistically significantly higher for PBS than PreserveCyt at 36 h (31.00 vs 29.26), and 48 h (31.06 vs 28.70). A retrospective analysis in 47 clinical PreserveCyt collected samples that were positive for HPV16 DNA found that 1 case (2%) would become negative if collected in ice-cold PBS. Conclusions: The PBS might be an alternative collecting medium for HPV detection in the low-resource areas. Further evaluations are warranted.     

Chemical constituents of the Thai medicinal plant, <Emphasis Type="Italic">Dioecrescis erythroclada</Emphasis> (Kurz) Tirveng

Six compounds were isolated from the leaves and branches of Dioecrescis erythroclada and identified as apodanthoside, mussaenoside, gardenoside, benzyl alcohol O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside, phenethyl alcohol O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside, and oct-1-en-3-ol α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside. The structures were determined based on physical data and spectroscopic evidence.