Caretakers' barriers to pediatric antiretroviral therapy adherence in Vietnam - A qualitative and quantitative study.

BACKGROUND: Poor antiretroviral therapy (ART) adherence leads to drug resistance and treatment failures. The options for second and third line ART regimens, particularly for pediatric patients, are very limited in low and middle-income countries. HIV-infected children are mostly passive drug-takers, thus caretakers play a very important role in assuring ART adherence. Pediatric ART adherence is still a challenging problem in Vietnam since non-adherence is the major risk factor for treatment failure. Our study explores and measures caretakers' barriers in order to improve pediatric ART adherence in future. METHODS: Exploring caretakers' barriers was conducted through a qualitative study with Focus Group Discussion (FGD) on two topics: 1. Current society - family support and difficulties in taking care children under ART; 2. Stigma experience. Based on the finding from the qualitative study a quantitative study measuring caretakers' barriers was conducted through a designed questionnaire. Study methods strictly followed the consolidated criteria with 32-item checklist for interviews and focus groups. RESULTS: In total eight FGDs with 53 participants were conducted. Common caretakers' barriers to children's ART adherence, were financial burden, lack of ART KP (Knowledge-Practice), stigma, depression, shifting caretaker, drug taste and side effects, lack of family support, fixed health check-up schedule and HIV non-disclosure. In the questionnaire study a total of 209 caretakers participated. The most commonly reported caretakers' barriers were: financial burden (144; 69%), KP burden (143; 68%), depression (85; 41%) and stigma (30; 14.8%). Some caretakers' characteristics that significantly associated with reported barriers (p<0.05). Rural caretakers reported significantly more financial burden (OR=2.26) and stigma (OR=3.53) than urban. Caretakers with under high school level education reported significantly more financial burdens (OR=2.08) and stigma (OR=4.15) compared to caretakers with high school education or over. CONCLUSION: Financial burden, KP burden, depression and stigma were common reported caretakers' barriers to pediatric ART adherence. Family residence, caretaker's education level and job were considered as the key factors determining caretakers' barriers related to financial burden and stigma. These findings may be important for policy makers and researchers in order to develop effective interventions regarding to caretakers' burdens and associated factors. Furthermore, a tool for nurses in monitoring caretakers' barriers to pediatric ART adherence was developed first with FDG, and then interview questionnaire. This tool could be applied and modified easily in any pediatric ART clinic settings in accordance to economic, social and cultural circumstances.

The use of the RESPeRATE device to lower blood pressure in inner city obese adolescents and children: a pilot feasibility study.

The RESPeRATE device was tested for feasibility of use in a population of overweight and obese children and adolescents (n = 10) in San Francisco, CA. After a 2-week and then a 2-month period, participants were interviewed on their frequency of use and attitudes towards the device. A high percentage stated that they enjoyed using the device at 2 months (90%) and 80% stated that they would recommend use to a friend or relative. Future studies are needed to assess the efficacy of the RESPeRATE device in lowering blood pressure and helping with weight loss/weight management in obese and overweight children.

Mannan-binding lectin is a determinant of survival in infective endocarditis.

Mannan-binding lectin (MBL) is a collectin plasma protein activating the lectin pathway of the complement system, enhancing opsonophagocytosis and modulating the cytokine response to inflammation. Deficiency of MBL, caused by structural mutations or promoter polymorphisms in the MBL2 gene, has been associated with increased susceptibility to infection and autoimmune disease. Thus, as infective endocarditis remains a severe disease requiring intensive and long-term treatment with antibiotics, we examined whether there was an association between MBL and clinical outcome in 39 well-characterized patients with infective endocarditis. Five patients (13%) had MBL concentrations < 100 microg/l and were considered MBL-deficient. This proportion was similar to that in a healthy control group of blood donors. Mortality 3 months after diagnosis was 20% in patients with MBL-deficiency and 9% in patients with normal MBL. The 5-year mortality was 80% and 25%, respectively. MBL-deficiency was on univariate survival statistics associated with significantly higher mortality on follow-up (P=0 x 03). In conclusion, this is the first report of an association between MBL-deficiency and survival in infective endocarditis. The present observation is important, as replacement therapy in MBL-deficient patients is possible. For certain high-risk subgroups, it opens new perspectives for improvement of treatment and outcome in infective endocarditis.

Common genetic variation in a basal promoter element alters DDAH2 expression in endothelial cells.

Synthesis of the vasodilator nitric oxide (NO) can be inhibited by the endogenous methylarginines L-NMMA and ADMA. ADMA is elevated in a number of cardiovascular disorders in which NO availability is reduced. Elimination of ADMA from the body occurs primarily by enzymatic breakdown through the action of DDAH, of which two isoforms exist, DDAH1 and DDAH2. In this study we have identified a core promoter region of the DDAH2 gene, and transcription factor sites that play an important role in the regulation of DDAH2 expression. Using PCR-SSCP analysis we also identified six common polymorphisms. One of these polymorphisms (an insertion/deletion at position -871) within the core promoter element influenced basal transcription. The discovery of a functional polymorphism within the DDAH2 promoter suggests that there may be common, individual differences in the ability to metabolise ADMA in vivo, that in turn, might underlie susceptibility to cardiovascular disease.

Do hair care practices affect the acquisition of tinea capitis? A case-control study.

OBJECTIVE: To determine the influences of hair-grooming practices and environmental factors as risk factors for the acquisition of tinea capitis (TC) in children. DESIGN: Case-control study comparing children with culture-proved TC with age-, sex-, and race-matched control subjects without scalp disease. SETTING: A multicenter study involving 3 urban referral centers in the United States. PARTICIPANTS: A convenience sample of 66 patients aged 12 years and younger presenting to pediatric dermatology clinics with clinical evidence of TC were enrolled as cases. Matched control subjects (n = 68), without known scalp disease, were enrolled from the outpatient pediatric clinics at the same institutions. RESULTS: Significant associations with TC in the conditional logistic regression model were a prior history of TC (odds ratio, 3.11; 95% confidence interval, 1.02-9.43; P =.04) and exposure to TC (odds ratio, 16.32; 95% confidence interval, 3.55-75.16; P =.001). The use of a hair conditioner was statistically significant in the univariable model but not in the multivariable model (odds ratio, 0.46; 95% confidence interval, 0.20-1.08; P =.07). Hairstyling, frequency of washing, use of oils or grease, and other hair care practices were not shown to be associated with the presence of TC. CONCLUSIONS: Hair-grooming practices do not appear to play a major role in the acquisition of TC. Hair conditioners may be protective in children at risk for TC, but further studies are needed to confirm this finding.

Chromosomal localization, gene structure, and expression pattern of DDAH1: comparison with DDAH2 and implications for evolutionary origins.

Endogenously produced asymmetrically methylated arginine residues are competitive inhibitors of all three isoforms of nitric oxide synthase (NOS). The enzyme dimethylarginine dimethylaminohydrolase (DDAH) specifically hydrolyzes these asymmetrically methylated arginine residues to citrulline and methylamines. Previously we have proposed that regulation of asymmetric methylarginine concentration by DDAH may provide a novel mechanism for the regulation of NOS activity in vivo. Recently we reported the cloning of human DDAH and identified a novel human DDAH isoform (DDAH I and DDAH II, respectively). Here we report that the DDAH1 gene maps to chromosome 1p22 and confirm that DDAH2 maps to the MHC III region of chromosome 6p21.3. Extensive analysis of the distribution of DDAH1 and DDAH2 mRNA in 50 human tissues indicates differential expression of DDAH isoforms in brain regions, in immune cells, and during development. DDAH2 expression predominates in highly vascularized tissues that express the endothelial NOS isoform and in immune tissues that can express iNOS. Whereas DDAH2 is expressed at relatively high levels in all fetal tissues examined, DDAH1 expression varies little between fetal and adult tissues. The chromosomal localization of the DDAHs is consistent with gene duplication, and consistent with this, comparison of the gene structures indicates that the intron/exon organization is highly conserved. Phylogenetic analysis of DDAH sequences from diverse species suggests that DDAH gene duplication occurred prior to the emergence of bony fish some 400 million years ago. Overall the data suggest that DDAH2 may be the more ancient of the two genes.

The epidemiology of typhoid fever in the Dong Thap Province, Mekong Delta region of Vietnam.

A population-based surveillance for typhoid fever was conducted in three rural communes of Dong Thap Province in southern Vietnam (population 28,329) for a 12-month-period starting on December 4, 1995. Cases of typhoid fever were detected by obtaining blood for culture from residents with fever > or = 3 days. Among 658 blood cultures, 56 (8.5%) were positive for Salmonella typhi with an overall incidence of 198 per 10(5) population per year. The peak occurrence was at the end of the dry season in March and April. The attack rate was highest among 5-9 year-olds (531/10(5)/year), and lowest in > 30 year-olds (39/10(5)/year). The attack rate was 358/10(5)/year in 2-4 year-olds. The isolation of S. typhi from blood cultures was highest (17.4%) in patients with 5 to 6 days of fever. Typhoid fever is highly endemic in Vietnam and is a significant disease in both preschool and school-aged children.

Requirement for EphA receptor signaling in the segregation of Xenopus third and fourth arch neural crest cells.

We describe here the isolation of a full-length cDNA encoding a Xenopus orthologue of the mammalian EphA2 receptor tyrosine kinase and investigate its role in cranial neural crest migration. We show that the primary sites of Xenopus EphA2 expression are rhombomere 4 of the developing hindbrain, migratory cranial neural crest cells and mesoderm of the visceral arches. To interfere with EphA2 and related receptors during cranial neural crest migration, we took a dominant negative approach. Overexpression of kinase-deficient EphA2 receptor variants led to abnormal migration of cranial neural crest cells. Neural crest cells of the third arch were found to mismigrate posteriorly, resulting in the failure of third and fourth arch neural crest to separate into distinct streams. These defects could be rescued by expression of full-length EphA2 receptors. A comparison of the expression domains of EphA2-binding proteins mapped by receptor affinity probe (RAP) in situ staining with those for EphA2 receptors revealed co-expression of ligands and receptors in the visceral arch mesenchyme. Taken together, these results suggest that EphA receptors may mediate attractive or adhesive signals during migration of cranial neural crest cells.

Differential expression of MHC class II molecules by microglia and neoplastic astroglia: relevance for the escape of astrocytoma cells from immune surveillance.

There is increasing evidence that microglia serve as antigen presenters in the human CNS. Although the occurrence of MHC class II immunoreactive cells has been reported in astrocytic gliomas, the relative contribution of microglia to this cell population has not been studied in detail. Using computer-assisted image analysis, we have investigated the expression of MHC class II molecules and of the microglia/macrophage markers Ki-MIP, RCA-1, KP1 and iba1, in 97 astrocytic gliomas comprising all WHO grades to answer the question whether there is a correlation between tumour grade and the number of MHC class II positive microglia/macrophage profiles. Microglia expressing MHC class II were common in astrocytomas and anaplastic astrocytomas but rare in pilocytic tumours although there was significant variation within each group. MHC class II immunoreactivity was reduced in highly cellular areas of glioblastomas where large numbers of cells expressing macrophage markers were still present. Thus, there was no simple relationship between tumour grade and microglial/macrophage MHC class II expression. In addition, up to 55% of astrocytic gliomas contained MHC class II immunoreactive tumour cells. Microglia but not tumour cells were found to express the BB1/B7 costimulator. We conclude that microglia in astrocytic gliomas are well equipped to function as antigen presenting cells. Yet, neoplastic astroglia appear to acquire the capacity to downregulate microglial MHC class II expression and, at the same time, may induce T-cell clonal anergy through aberrant expression of MHC class II molecules.

The replication behavior of Saccharomyces cerevisiae DNA in human cells.

We studied the replication of random genomic DNA fragments from Saccharomyces cerevisiae in a long-term assay in human cells. Plasmids carrying large yeast DNA fragments were able to replicate autonomously in human cells. Efficiency of replication of yeast DNA fragments was comparable to that of similarly sized human DNA fragments and better than that of bacterial DNA. This result suggests that yeast genomic DNA contains sequence information needed for replication in human cells. To examine whether DNA replication in human cells would initiate specifically at a yeast origin of replication, we monitored initiation on a plasmid containing the yeast 2-micron autonomously replicating sequence (ARS) in yeast and human cells. We found that while replication initiates at the 2-micron ARS in yeast, it does not preferentially initiate at the ARS in human cells. This result suggests that the sequences that direct site specific replication initiation in yeast do not function in the same way in human cells, which initiate replication at a broader range of sequences.

Autonomous DNA replication in human cells is affected by the size and the source of the DNA.

We previously developed short-term and long-term assays for autonomous replication of DNA in human cells. This study addresses the requirements for replication in these assays. Sixty-two random human genomic fragments ranging in size from 1 to 21 kb were cloned in a prokaryotic vector and tested for their replication ability in the short-term assay. We found a positive correlation between replication strength and fragment length, indicating that large size is favored for efficient autonomous replication in human cells. All large fragments replicated efficiently, suggesting that signals which can direct the initiation of DNA replication in human cells are either very abundant or have a low degree of sequence specificity. Similar results were obtained in the long-term assay. We also used the same assays to test in human cells a random series of fragments derived from Escherichia coli chromosomal DNA. The bacterial fragments supported replication less efficiently than the human fragments in the short-term and long-term assays. This result suggests that while the sequence signals involved in replication in human cells are found frequently in human DNA, they are uncommon in bacterial DNA.

Hepatitis B virus particles of plasma and liver contain viral DNA-RNA hybrid molecules.

Hepatitis B virions in plasma (Dane particles) are known to contain small circular DNA molecules. The experiments described here indicate that virions in plasma, as well as particles from hepatitis B virus-infected human liver, also contain viral DNA-RNA hybrid molecules, and deoxynucleotides can be incorporated into the DNA of these hybrids by DNA polymerase activities in the virions. Thus, two viral DNA synthetic reactions appear to take place in virions: repair of the single-stranded region of circular DNA molecules and synthesis or elongation of the DNA strand of DNA-RNA hybrid molecules. Centrifugation of virion nucleic acid to equilibrium in Cs2SO4 density gradients revealed the presence of viral DNA-RNA hybrid molecules over a density range of 1.45 to 1.60 g/cm3. Distinct species of hybrid molecules were found with an average density of 1.57 g/cm3 in Dane particles and 1.52 and 1.57 g/cm3 in particles from liver. Fractionation of nucleic acid from Cs2SO4 density gradients by gel electrophoresis demonstrated that the majority of hybrid molecules migrated faster than molecules with the density of pure DNA (1.42 g/cm3). One notable exception was the finding of DNA-RNA hybrid molecules migrating slower than open circular viral DNA. Characterization of viral DNA-RNA hybrids by heat denaturation Cs2SO4 density gradient fractionation, and recombinant M13-HBV single-stranded probe hybridization revealed that the hybrid molecules consisted of viral plus-strand RNA hydrogen bonded to viral minus-strand DNA sequences. Data obtained by pancreatic ribonuclease digestion revealed that the hybrid molecules at density 1.45 to 1.52 g/cm3 contained HBV RNA strands base paired over only part of their length in contrast to the hybrid species at density 1.57 g/cm3 which contained RNA strands apparently base paired over most of their length. Further characterization showed that the hybrid at 1.57 g/cm3 contained genome-length minus-strand viral DNA. The experiments rule out the possibility that the hybrid molecules are transcriptional complexes. Data presented in a companion manuscript indicate that the hybrid molecules may represent intermediates in the synthesis of viral DNA in the endogenous DNA polymerase reaction.

Characterization of low potassium-resistant mutants of the Madin-Darby canine kidney cell line with defects in NaCl/KCl symport.

Three independent mutants of the Madin-Darby canine kidney cell line (MDCK) have been isolated which were capable of growth in media containing low concentrations of potassium. All three mutants were deficient to varying extents in furosemide- and bumetanide-sensitive 22Na+, 86+b+, and 36Cl- uptake. The two mutants most resistant to low K+ media had lost essentially all of the 22Na+, 86Rb+, and 36Cl- uptake activities of this system. The third mutant was partially resistant to low K+ media and had reduced levels of bumetanide-sensitive uptake for all three ions. Extrapolated initial uptake rates for 22Na+, 86Rb+, and 36Cl- revealed that the partial mutant exhibited approximately 50% of the parental uptake rates for all three ions. The stoichiometries of bumetanide-sensitive uptake in both the parental cell line and the partial mutant approximated 1 Rb+:1 Na+:2 Cl-. The results of this study provide genetic evidence for a single tightly-coupled NaCl/KCl symporter in MDCK cells. The correlation between the ability to grow in low K+ media and decreased activity of the bumetanide-sensitive co-transport system suggests that the bumetanide-sensitive transport system catalyzes net K+ efflux from cells in low K+ media. The results of 86Rb+ efflux studies conducted on ouabain-pretreated mutant and parental cells are consistent with this interpretation. Cell volume measurements made on cells at different densities in media containing normal K+ concentrations showed that none of the mutants differed significantly in volume from the parental strain at a similar cell density. Furthermore, all three mutants were able to readjust their volume after suspension in hypotonic media. These results suggest that in the MDCK cell line, the bumetanide-sensitive NaCl/KCl symport system does not function in the regulation of cell volume under the conditions employed.

Pituitary response of prepuberal lambs to oestradiol-17 beta.

In two experiments 48 prepuberal Merino ewe lambs were injected with oestradiol-17 beta (E2) or saline to study the effect of E2 on their plasma LH levels and on oestrus and ovulation. In the three groups which received 30 (experiment I), 50 and 30 (experiment II) microgram E2 respectively, 27 out of 28 lambs showed an LH response, the corresponding mean LH peaks being 64.3 +/0 22.5, 153.6 +/-33.4 and 91.7 +/- 16.9 ng/ml at mean intervals of 11.1, 11.2 and 10.5 h, respectively, after injection. None of the 20 lambs in the control groups had an LH level higher than 18 ng/ml 12 h after injection. In the three E2 groups, 41.7, 62.5 and 37.5% of animals showed oestrus within 26 h of injection while in the control groups only one animal showed oestrus. Of 13 animals showing oestrus in the E2 groups, 11 failed to ovulate. The mean pre-injection plasma FSH level in experiment I was 102.7 ng/ml, and in four 5--7-month-old lambs over several weeks uas 155.3 ng/ml. Despite these high pre-injection levels of FSH, it appears that the follicles were unable to respond to the LH peak which followed the E2 injection.