Spectrum of mutations in Gitelman syndrome

Gitelman's syndrome (GS) is a rare, autosomal recessive, salt-losing tubulopathy caused by mutations in the SLC12A3 gene, which encodes the thiazide-sensitive NaCl cotransporter (NCC). Because 18 to 40% of suspected GS patients carry only one SLC12A3 mutant allele, large genomic rearrangements may account for unidentified mutations. Here, we directly sequenced genomic DNA from a large cohort of 448 unrelated patients suspected of having GS. We found 172 distinct mutations, of which 100 were unreported previously. In 315 patients (70%), we identified two mutations; in 81 patients (18%), we identified one; and in 52 patients (12%), we did not detect a mutation. In 88 patients, we performed a search for large rearrangements by multiplex ligation-dependent probe amplification (MLPA) and found nine deletions and two duplications in 24 of the 51 heterozygous patients. A second technique confirmed each rearrangement. Based on the breakpoints of seven deletions, nonallelic homologous recombination by Alu sequences and nonhomologous end-joining probably favor these intragenic deletions. In summary, missense mutations account for approximately 59% of the mutations in Gitelman's syndrome, and there is a predisposition to large rearrangements (6% of our cases) caused by the presence of repeated sequences within the SLC12A3 gene.     

Role for interferon-gamma release assays in latent tuberculosis screening before TNF-α antagonist therapy

TNF-α antagonist therapy is associated with a risk of severe, extrapulmonary, disseminated tuberculosis, which is fatal in 10% of cases. The risk of tuberculosis is increased four-fold in patients on TNF-α antagonist therapy. The main risk factors are a history of untreated or inadequately treated primary tuberculosis, recent contact with a tuberculosis patient, and residence in or travel to a high-endemicity region. Infection surveillance agencies throughout the world have issued recommendations to ensure the detection and treatment of latent tuberculosis before TNF-α antagonist initiation. These recommendations have returned the incidence of tuberculosis to the level seen before the introduction of TNF-α antagonists. Nevertheless, there is still room for improvement. Recommendations about latent tuberculosis screening include the use of tuberculin skin tests. However, these tests are positive in individuals vaccinated with the BCG vaccine, which leads to overuse of tuberculosis chemoprophylaxis and, therefore, to unnecessary patient exposure to hepatotoxic effects. Furthermore, tuberculin skin tests may be falsely negative in immunosuppressed patients, leading to underuse of tuberculosis prophylaxis. These shortcomings of tuberculin skin tests have generated interest in interferon-gamma release assays (IGRAs). In patients with overt tuberculosis, IGRAs are more sensitive and more specific than tuberculin skin tests. However, the accuracy of IGRAs for diagnosing latent tuberculosis remains unknown, because no reference standard is available. In addition, patients taking immunosuppressant agents to treat systemic disease may exhibit anergia, which complicates the interpretation of IGRAs. Until additional data become available, caution requires that IGRAs be used only when a positive or negative result, as assessed on a case-by-case basis, will help to decide whether tuberculosis chemoprophylaxis is in order.     

The mouse cerebellar cortex in organotypic slice cultures: an in vitro model to analyze the consequences of mutations and pathologies on neuronal survival, development, and function

Thin acute slices and dissociated cell cultures taken from different parts of the brain have been widely used to examine the function of the nervous system, neuron-specific interactions, and neuronal development (specifically, neurobiology, neuropharmacology, and neurotoxicology studies). Here, we focus on an alternative in vitro model: brain-slice cultures in roller tubes, initially introduced by Beat G?hwiler for studies with rats, that we have recently adapted for studies of mouse cerebellum. Cultured cerebellar slices afford many of the advantages of dissociated cultures of neurons and thin acute slices. Organotypic slice cultures were established from newborn or 10-15-day-old mice. After 3-4 weeks in culture, the slices flattened to form a cell monolayer. The main types of cerebellar neurons could be identified with immunostaining techniques, while their electrophysiological properties could be easily characterized with the patch-clamp recording technique. When slices were taken from newborn mice and cultured for 3 weeks, aspects of the cerebellar development were displayed. A functional neuronal network was established despite the absence of mossy and climbing fibers, which are the two excitatory afferent projections to the cerebellum. When slices were made from 10-15-day-old mice, which are at a developmental stage when cerebellum organization is almost established, the structure and neuronal pathways were intact after 3-4 weeks in culture. These unique characteristics make organotypic slice cultures of mouse cerebellar cortex a valuable model for analyzing the consequences of gene mutations that profoundly alter neuronal function and compromise postnatal survival.     

Postnatal cellular contributions of the hippocampus subventricular zone to the dentate gyrus, corpus callosum, fimbria, and cerebral cortex

The rodent dentate gyrus (DG) is formed in the embryo when progenitor cells migrate from the dentate neuroepithelium to establish a germinal zone in the hilus and a secondary germinal matrix, near the fimbria, called the hippocampal subventricular zone (HSVZ). The developmental plasticity of progenitors within the HSVZ is not well understood. To delineate the migratory routes and fates of progenitors within this zone, we injected a replication-incompetent retrovirus, encoding the enhanced green fluorescent protein (EGFP), into the HSVZ of postnatal day 5 (P5) mice. Between P6 and P45, retrovirally-infected EGFP(+) of progenitors migrated into the DG, established a reservoir of progenitor cells, and differentiated into neurons and glia. By P6-7, EGFP(+) cells were observed migrating into the DG. Subsets of these EGFP(+) cells expressed Sox2 and Musashi-1, characteristic of neural stem cells. By P10, EGFP(+) cells assumed positions within the DG and expressed immature neuronal markers. By P20, many EGFP(+) cells expressed the homeobox prospero-like protein Prox1, an early and specific granule cell marker in the CNS, and extended mossy fiber projections into the CA3. A subset of non-neuronal EGFP(+) cells in the dentate gyrus acquired the morphology of astrocytes. Another subset included EGFP(+)/RIP(+) oligodendrocytes that migrated into the fimbria, corpus callosum, and cerebral cortex. Retroviral injections on P15 labeled very few cells, suggesting depletion of HSVZ progenitors by this age. These findings suggest that the early postnatal HSVZ progenitors are multipotent and migratory, and contribute to both dentate gyrus neurogenesis as well as forebrain gliogenesis.     

Bridging Health Care and the Workplace: Formulation of a Return-to-Work Intervention for Breast Cancer Patients Using an Intervention Mapping Approach

Purpose An increasing number of breast cancer (BC) survivors of working age require return to work (RTW) support. Objective of this paper is to describe the development of a RTW intervention to be embedded in the care process bridging the gap between hospital and workplace. Method The Intervention Mapping (IM) approach was used and combined formative research results regarding RTW in BC patients with published insights on occupational therapy (OT) and RTW. Four development steps were taken, starting from needs assessment to the development of intervention components and materials. Results A five-phased RTW intervention guided by a hospital-based occupational therapist is proposed: (1) assessing the worker, the usual work and contextual factors which impacts on (re-)employment; (2) exploration of match/differences between the worker and the usual work; (3) establishing long term goals, broken down into short term goals; (4) setting up tailored actions by carefully implementing results of preceding phases; (5) step by step, the program as described in phase 4 will be executed. The occupational therapist monitors, measures and reviews goals and program-steps in the intervention to secure the tailor-made approach of each program-step of the intervention. Conclusion The use of IM resulted in a RTW oriented OT intervention. This unique intervention succeeds in matching individual BC patient needs, the input of stakeholders at the hospital and the workplace.     

Nutrition intervention and adequate hygiene practices to improve iron status of vulnerable preschool Burkinabe children

ObjectiveTo determine the impact of an intervention that combined an increase in dietary and bioavailable iron intakes and an improvement in hygiene behaviors on the iron status of preschool children from Burkina Faso.MethodsThirty-three orphans and vulnerable children from 11 families who were 1–6 y old, were non-anemic, or had mild to moderate anemia were enrolled in an 18-wk trial. Using the probability approach for planning diets in an assisted-living facility, bioavailable iron intake was increased from 0.4 to 0.9 mg/d by increasing the amounts of meat and citrus fruits and by adding iron-rich condiments to the diet, for an estimated cost of U.S. $0.59/mo. Hygiene behaviors were modified by implementing hand-washing before meals and by the use of individual plates for meals. Iron status indicators were measured twice and means at enrollment and after intervention were compared.ResultsAfter intervention, hemoglobin concentration increased from 98.7 to 103.8 g/L (P = 0.006). There was a decrease in total iron binding capacity (107 to 91 μmol/L, P = 0.05) and a marginal increase in transferrin saturation (13% to 17%, P = 0.06). Significant improvement was not observed for serum ferritin concentration or prevalence of depleted iron stores, likely due to the confounding effect of infection. Anemia and iron-deficiency anemia were decreased from 64% to 30% and from 61% to 30%, respectively.ConclusionDietary modification associated with adequate hygiene behaviors could be a relevant strategy to control iron deficiency and anemia in areas where infection is a major health problem.