Allergen sensitisation among chronic respiratory diseases in urban and rural areas of the south of Viet Nam.

OBJECTIVE: To evaluate the prevalence of and risk factors for allergen sensitisation among patients with chronic respiratory disease (CRD) in southern Viet Nam. DESIGN: An environmental questionnaire and skin prick tests for airborne and food allergens were administered to patients with CRD, defined as individuals with respiratory symptoms and lung function defects. RESULTS: Of 610 CRD patients, 56% had chronic obstructive pulmonary disease and 31% were asthma patients; 80% were males. The most frequent sensitisers were dust mites (Dermatophagoides farinae 22%, Blomia tropicalis 19%, D. pteronyssinus 18%) and cockroach droppings (13%). Among study participants, 37% were from rural settings and 36% from urban areas, whereas 27% had migrated from rural to urban areas. Compared with people from rural areas, being born in an urban area was a risk factor for sensitisation to mites (OR 1.56, 95%CI 1.11-2.20, P < 0.02). In multivariate analysis, place of birth remained a risk factor for mite sensitisation. Compared with the native urban population, the risk of mite sensitisation was not significantly different among patients born in rural areas and those migrating to urban areas. CONCLUSION: Dust mites and cockroach droppings were the most frequent allergens among people with CRD in the south of Viet Nam. Compared with the urban population, being native to a rural area was protective against mite sensitisation, but this effect ceased to be significant after migration from rural to urban areas.

[Practical problems related to the management of febrile urinary tract infection in Vietnamese children]. / Difficultés de prise en charge des infections urinaires fébriles chez l'enfant vietnamien.

BACKGROUND: To describe the practical problems related to urinary tract infection (UTI) management in febrile Vietnamese children. METHODS: During a prospective 28-month inclusion period, 143 febrile children with significant bacteriuria were treated for UTI in the nephrology department of Nhi Dong 2 children's hospital in Ho Chi Minh City, Vietnam. Patients were treated after blood and urine samples had been taken for culture, according to a local antibiotic protocol, parenterally with ceftriaxone 75mg/kg/day. Oral treatment with cefixime 8mg/kg/day was started after 48h of apyrexia for 2 weeks. According to local protocol, antibiotic therapy was only changed if children did not respond clinically to treatment regardless of antibiogram results. RESULTS: Among these 143 children, 51% were girls and 80% of them had their first UTI before the age of 2 years. The commonest causative agent was Escherichia coli (80% of cases) with a high resistance rate to ampicillin (91%) and cotrimoxazole (74%). Extended-spectrum ß-lactamase (ESBL) production was observed in 52% of Enterobacteriaceae isolates. According to antibiotic susceptibility, the initial treatment with ceftriaxone was found to be inappropriate in 63% of cases. CONCLUSIONS: E. coli was responsible for 80% of UTIs in Vietnamese children with a high rate of resistance to first-line antibiotics. ESBL production was found to be extremely high in this study. Based on these data, we propose a new empiric treatment schedule for Vietnamese children suspected of UTI.

Transformation in the methylotrophic yeast Pichia methanolica utilizing homologous ADE1 and heterologous Saccharomyces cerevisiae ADE2 and LEU2 genes as genetic markers.

Development of transformation systems for methylotrophic yeasts is the starting point for research aimed at developing molecular genetics of these genera and will be the key to their further successful use in biotechnology. We transformed Pichia methanolica using selector genes ADE2 and LEU2 from Saccharomyces cerevisiae and ADE1 (homologue of S. cerevisiae ADE2 gene) from P. methanolica which was cloned and sequenced in our laboratory (Hiep et al., 1991). Lithium transformation of P. methanolica strains was inefficient with intact plasmids. Linearization of plasmids at a unique restriction site within the ADE1 gene prior to transformation substantially increased its frequency. Transformation with linear ADE1, ADE2 or LEU2 gene fragments was even more effective. Introduced DNA fragments either circularized in vivo, irrespective of the structures of their ends, giving unstable transformants; or integrated at different sites of the host genome. Using this transformation system, we obtained a disruption of the ADE1 gene on the chromosome by inserting the S. cerevisiae LEU2 gene. The disruption mutation ade1::LEU2 was used to study the mechanism of intragenic recombination in P. methanolica.

The 5-aminoimidazole ribonucleotide-carboxylase structural gene of the methylotrophic yeast Pichia methanolica: cloning, sequencing and homology analysis.

The ADE1 gene of the yeast Pichia methanolica encodes phosphoribosyl-5-aminoimidazole-carboxylase (AIRC, EC 4.1.1.21), which is involved in purine biosynthesis. The gene was cloned by complementation of an ade2 mutation in Saccharomyces cerevisiae and a 3077 nucleotide DNA fragment was sequenced. The sequence possessed a single open reading frame, corresponding to a 543 amino acid sequence. The sequence of this putative protein has been compared to the proteins of homologous genes from S. cerevisiae, Schizosaccharomyces pombe, Escherichia coli, chicken and man. The analysis revealed remarkable homology between yeast AIRCs, while for other proteins homology was limited to defined regions.