Publications

Racial and ethnic disparities exist in both incidence and stage detection of colorectal cancer (CRC). We hypothesized that cultural practices (i.e., communication norms and expectations) influence patients' and their physicians' understanding and talk about CRC screening. We examined 44 videotaped observations of clinic visits that included a CRC screening recommendation and transcripts from semistructured interviews that doctors and patients separately completed following the visit. We found that interpersonal relationship themes such as power distance, trust, directness/ indirectness, and an ability to listen, as well as personal health beliefs, emerged as affecting patients' definitions of provider-patient effective communication. In addition, we found that in discordant physician-patient interactions (when each is from a different ethnic group), physicians did not solicit or address cultural barriers to CRC screening and patients did not volunteer culture-related concerns regarding CRC screening.

The accessory Sec system of Streptococcus gordonii is essential for transport of the glycoprotein GspB to the bacterial cell surface. A key component of this dedicated transport system is SecA2. The SecA2 proteins of streptococci and staphylococci are paralogues of SecA and are presumed to have an analogous role in protein transport, but they may be specifically adapted for the transport of large, serine-rich glycoproteins. We used a combination of genetic and biochemical methods to assess whether the S. gordonii SecA2 functions similarly to SecA. Although mutational analyses demonstrated that conserved amino acids are essential for the function of SecA2, replacing such residues in one of two nucleotide binding folds had only minor effects on SecA2 function. SecA2-mediated transport is highly sensitive to azide, as is SecA-mediated transport. Comparison of the S. gordonii SecA and SecA2 proteins in vitro revealed that SecA2 can hydrolyze ATP at a rate similar to that of SecA and is comparably sensitive to azide but that the biochemical properties of these enzymes are subtly different. That is, SecA2 has a lower solubility in aqueous solutions and requires higher Mg(2+) concentrations for maximal activity. In spite of the high degree of similarity between the S. gordonii paralogues, analysis of SecA-SecA2 chimeras indicates that the domains are not readily interchangeable. This suggests that specific, unique contacts between SecA2 and other components of the accessory Sec system may preclude cross-functioning with the canonical Sec system.

BACKGROUND

Home management of malaria-the presumptive treatment of febrile children with antimalarial drugs-is advocated to ensure prompt effective treatment of the disease. We assessed the effect of home delivery of artemether-lumefantrine on the incidence of antimalarial treatment and on clinical outcomes in children from an urban setting with fairly low malaria transmission.

METHODS

In Kampala, Uganda, 437 children aged between 1 and 6 years from 325 households were randomly assigned by a computer-generated sequence to receive home delivery of prepackaged artemether-lumefantrine for presumptive treatment of febrile illnesses (n=225) or current standard of care (n=212). Randomisation was done by household after a pilot period of 1 month. After randomisation, study participants were followed up for an additional 12 months and information on their health and treatment of illnesses was obtained by use of monthly questionnaires and household diaries, which were completed by the participants' carers. The primary outcome was treatment incidence density per person-year. Analysis of the primary outcome was done on the modified intention-to-treat population, which included all participants apart from those excluded before data collection. This trial is registered with ClinicalTrials.gov, number NCT00115921.

FINDINGS

Eight participants in the home management group and four in the standard care group were excluded before data collection; therefore, the primary analysis was done in 217 and 208 participants, respectively. The home management group received nearly twice the number of antimalarial treatments as the standard care group (4.66 per person-year vs 2.53 per person-year; incidence rate ratio [IRR] 1.72, 95% CI 1.43-2.06, p<0.0001), and nearly five times the number given to children with microscopically confirmed malaria in a comparable cohort of children (4.66 per person-year vs 1.03 per person-year, IRR 5.19, 95% CI 4.24-6.35, p<0.0001). Clinical data were available for 189 children in the home management group and 176 in the control group at study end; the main reasons for exclusion were movement out of the study area or loss to follow-up. The proportion of participants with parasitaemia at final assessment in the intervention group was lower than in the control group (four [2%] vs 17 [10%], p=0.006), but there were no other differences in standard malariometric indices, including anaemia. Serious adverse events were captured retrospectively. One child died in each group (home management-severe pneumonia and possible septicaemia; standard care-presumed respiratory failure).

INTERPRETATION

Although home management of malaria led to prompt treatment of fever, there was little effect on clinical outcomes. The substantial over-treatment suggests that artemether-lumefantrine provided in the home might not be appropriate for large urban areas or settings with fairly low malaria transmission.

FUNDING

Gates Malaria Partnership.

Protein disulfide isomerases (PDIs) aid protein folding and assembly by catalyzing formation and shuffling of cysteine disulfide bonds in the endoplasmic reticulum (ER). Many members of the PDI family are expressed in mammals, but the roles of specific PDIs in vivo are poorly understood. A recent homology-based search for additional PDI family members identified anterior gradient homolog 2 (AGR2), a protein originally presumed to be secreted by intestinal epithelial cells. Here, we show that AGR2 is present within the ER of intestinal secretory epithelial cells and is essential for in vivo production of the intestinal mucin MUC2, a large, cysteine-rich glycoprotein that forms the protective mucus gel lining the intestine. A cysteine residue within the AGR2 thioredoxin-like domain forms mixed disulfide bonds with MUC2, indicating a direct role for AGR2 in mucin processing. Mice lacking AGR2 were viable but were highly susceptible to colitis, indicating a critical role for AGR2 in protection from disease. We conclude that AGR2 is a unique member of the PDI family, with a specialized and nonredundant role in intestinal mucus production.

BACKGROUND

Developmental, physiological and tissue engineering studies critical to the development of successful myocardial regeneration therapies require new ways to effectively visualize and isolate large numbers of fluorescently labeled, functional cardiomyocytes.

METHODOLOGY/PRINCIPAL FINDINGS

Here we describe methods for the clonal expansion of engineered hESCs and make available a suite of lentiviral vectors for that combine Blasticidin, Neomycin and Puromycin resistance based drug selection of pure populations of stem cells and cardiomyocytes with ubiquitous or lineage-specific promoters that direct expression of fluorescent proteins to visualize and track cardiomyocytes and their progenitors. The phospho-glycerate kinase (PGK) promoter was used to ubiquitously direct expression of histone-2B fused eGFP and mCherry proteins to the nucleus to monitor DNA content and enable tracking of cell migration and lineage. Vectors with T/Brachyury and alpha-myosin heavy chain (alphaMHC) promoters targeted fluorescent or drug-resistance proteins to early mesoderm and cardiomyocytes. The drug selection protocol yielded 96% pure cardiomyocytes that could be cultured for over 4 months. Puromycin-selected cardiomyocytes exhibited a gene expression profile similar to that of adult human cardiomyocytes and generated force and action potentials consistent with normal fetal cardiomyocytes, documenting these parameters in hESC-derived cardiomyocytes and validating that the selected cells retained normal differentiation and function.

CONCLUSION/SIGNIFICANCE

The protocols, vectors and gene expression data comprise tools to enhance cardiomyocyte production for large-scale applications.