Characterization of rotavirus infection in children with acute gastroenteritis in Bengo province, Northwestern Angola, prior to vaccine introduction.

BACKGROUND: Rotavirus group A (RVA) is considered the leading cause of pediatric diarrhea, responsible for the high burden of diarrheal diseases in sub-Saharan Africa. Despite recent studies, the existent data are scarce for some African countries like Angola, a country with one of the highest RVA-related death estimates. The aim of this study was to determine the RVA detection rate and circulating genotypes in children less than five years of age with acute gastroenteritis attended at the Bengo General Hospital in Caxito, Bengo province, Angola, before vaccine introduction. METHODS: Between September 2012 and December 2013, 342 fecal specimens were collected from children enrolled. Positive samples for RVA by immunochromatographic rapid test were G and P-typed by hemi-nested type-specific multiplex PCR, and subgrouped for the VP6 gene. VP4 and VP7 genes from a subset of samples were sequenced for phylogenetic analysis. RESULTS: During the study period, a high RVA detection rate was registered (25.1%, 86/342). The age group most affected by RVA infection includes children under 6 months of age (p<0.01). Vomiting was highly associated with RVA infection (72.1%; p<0.001). From the 86 RVA-positive samples, 72 (83.7%) were genotyped. The most prevalent genotype was G1P[8] (34/72; 47.2%), followed by the uncommon G1P[6] (21/72; 29.2%), and G2P[4] (9/72; 12.5%). Only two G-types were found: G1 (60/72; 83.3%) and G2 (11/72; 15.3%). Among the P-genotypes, P[8] was the most prevalent (34/72; 47.2%), followed by P[6] (22/72; 30.6%) and P[4] (9/72; 12.5%). In the phylogenetic trees, the identified G and P-types clustered tightly together and with reference sequences in specific monophyletic groups, with highly significant bootstrap values (≥92%). CONCLUSION: This pre-vaccination study revealed, for the first time for Bengo province (Angola), the RVA genotype profile, including phylogenetic relationships, and a high RVA detection rate, supporting the immediate introduction of a RVA vaccine in the national immunization programme.

Comparing concentration methods: parasitrap® versus Kato-Katz for studying the prevalence of Helminths in Bengo province, Angola.

BACKGROUND: Helminth intestinal parasitoses are responsible for high levels of child mortality and morbidity. Hence, the capacity to diagnose these parasitoses and consequently ensure due treatment represents a factor of great importance. OBJECTIVES: The main objective of this study involves comparing two methods of concentration, parasitrap and Kato-Katz, for the diagnosis of intestinal parasitoses in faecal samples. METHODS: Sample processing made recourse to two different concentration methods: the commercial parasitrap® method and the Kato-Katz method. RESULTS: We correspondingly collected a total of 610 stool samples from pre-school and school age children. The results demonstrate the incidence of helminth parasites in 32.8% or 32.3% of the sample collected depending on whether the concentration method applied was either the parasitrap method or the Kato-Katz method. We detected a relatively high percentage of samples testing positive for two or more species of helminth parasites. We would highlight that in searching for larvae the Kato-Katz method does not prove as appropriate as the parasitrap method. CONCLUSION: Both techniques prove easily applicable even in field working conditions and returning mutually agreeing results. This study concludes in favour of the need for deworming programs and greater public awareness among the rural populations of Angola.

Foxn1 regulates key target genes essential for T cell development in postnatal thymic epithelial cells.

Thymic epithelial cell differentiation, growth and function depend on the expression of the transcription factor Foxn1; however, its target genes have never been physically identified. Using static and inducible genetic model systems and chromatin studies, we developed a genome-wide map of direct Foxn1 target genes for postnatal thymic epithelia and defined the Foxn1 binding motif. We determined the function of Foxn1 in these cells and found that, in addition to the transcriptional control of genes involved in the attraction and lineage commitment of T cell precursors, Foxn1 regulates the expression of genes involved in antigen processing and thymocyte selection. Thus, critical events in thymic lympho-stromal cross-talk and T cell selection are indispensably choreographed by Foxn1.

Cell Growth Dynamics in Embryonic and Adult Mouse Thyroid Revealed by a Novel Approach to Detect Thyroid Gland Subpopulations.

BACKGROUND: The thyroid is composed of endocrine epithelial cells, blood vessels, and mesenchyme. However, no data exist thus far on absolute cell numbers, relative distribution, and proliferation of the different cell populations in the developing and mature thyroid. The aim of this study was therefore to establish a flow cytometry protocol that allows detection and quantification of discrete cell populations in embryonic and adult murine thyroid tissues. METHODS: Cell-type anti-mouse specific antibodies were used for erythroid cells (Ter119), hematopoietic cells (CD45), epithelial cells (EpCam/CD326, E-cadherin/CD324), thyroid follicular cells and C-cells (Nkx2-1), endothelial cells (Pecam/CD31, Icam-1/CD54), and fibroblasts (PDGFRa/CD140a). Proliferating cells were detected after labeling with 5-bromo-2'-deoxyuridine (BrdU). For flow cytometry analyses, micro-dissected embryonic (E) and adult thyroids were pooled (E13.5, n = 25; E15.5, n = 15; E17.5, n = 15; adult, n = 4) in one sample. RESULTS: The absolute parenchymal cell numbers per mouse thyroid (M ± SD), excluding the large number of CD45(+) and Ter119(+) cells, increased from 7425 ± 1338 at E13.5 to 271,561 ± 22,325 in adult tissues. As expected, Nkx2-1(+) cells represented the largest cell population in adult tissues (61.2 ± 1.1%). Surprisingly, at all three embryonic stages analyzed, thyroid follicular cells and C-cells accounted only for a small percentage of the total thyroid cell mass (between 4.7 ± 0.4% and 9.4 ± 1.6%). In contrast, the largest cell population at all three embryonic stages was identified as PDGFRa/CD140a(+) fibroblasts (61.4 ± 0.4% to 77.3 ± 1.1%). However, these cells represented the smallest population in adult tissues (5.2 ± 0.8%). Pecam/CD31(+) endothelial cells increased from E13.5 to E15.5 from 3.7 ± 0.8% to 8.5 ± 3.0%, then remained stable at E17.5 and adult tissues. Proliferation rates were sizable during the entire organogenesis but differed between cell populations, with distinct proliferative peaks at E13.5 in epithelial cells (32.7 ± 0.6% BrdU(+) cells), and at E15.5 in endothelial cells (22.4 ± 2.4% BrdU(+) cells). Fibroblasts showed a constant proliferation rate in embryonic tissues. In adult tissues, BrdU(+) cells were between 0.1% and 0.4% in all cell types. CONCLUSIONS: Using a novel flow cytometry-based method, a previously unobserved highly dynamic growth pattern of thyroid cell populations during embryogenesis was uncovered. This approach will provide a useful new tool for cell function analyses in murine thyroid disease models.

Dynamic spatio-temporal contribution of single ß5t+ cortical epithelial precursors to the thymus medulla.

Intrathymic T-cell development is critically dependent on cortical and medullary thymic epithelial cells (TECs). Both epithelial subsets originate during early thymus organogenesis from progenitor cells that express the thymoproteasome subunit ß5t, a typical feature of cortical TECs. Using in vivo lineage fate mapping, we demonstrate in mice that ß5t(+) TEC progenitors give rise to the medullary TEC compartment early in life but significantly limit their contribution once the medulla has completely formed. Lineage-tracing studies at single cell resolution demonstrate for young mice that the postnatal medulla is expanded from individual ß5t(+) cortical progenitors located at the cortico-medullary junction. These results therefore not only define a developmental window during which the expansion of medulla is efficiently enabled by progenitors resident in the thymic cortex, but also reveal the spatio-temporal dynamics that control the growth of the thymic medulla.

Adult Thymic Medullary Epithelium Is Maintained and Regenerated by Lineage-Restricted Cells Rather Than Bipotent Progenitors.

Medullary thymic epithelial cells (mTECs) play an essential role in establishing self-tolerance in T cells. mTECs originate from bipotent TEC progenitors that generate both mTECs and cortical TECs (cTECs), although mTEC-restricted progenitors also have been reported. Here, we report in vivo fate-mapping analysis of cells that transcribe ß5t, a cTEC trait expressed in bipotent progenitors, during a given period in mice. We show that, in adult mice, most mTECs are derived from progenitors that transcribe ß5t during embryogenesis and the neonatal period up to 1 week of age. The contribution of adult ß5t(+) progenitors was minor even during injury-triggered regeneration. Our results further demonstrate that adult mTEC-restricted progenitors are derived from perinatal ß5t(+) progenitors. These results indicate that the adult thymic medullary epithelium is maintained and regenerated by mTEC-lineage cells that pass beyond the bipotent stage during early ontogeny.

Aire-expressing thymic medullary epithelial cells originate from ß5t-expressing progenitor cells.

The thymus provides multiple microenvironments that are essential for the development and repertoire selection of T lymphocytes. The thymic cortex induces the generation and positive selection of T lymphocytes, whereas the thymic medulla establishes self-tolerance among the positively selected T lymphocytes. Cortical thymic epithelial cells (cTECs) and medullary TECs (mTECs) constitute the major stromal cells that structurally form and functionally characterize the cortex and the medulla, respectively. cTECs and mTECs are both derived from the endodermal epithelium of the third pharyngeal pouch. However, the molecular and cellular characteristics of the progenitor cells for the distinct TEC lineages are unclear. Here we report the preparation and characterization of mice that express the recombinase Cre instead of ß5t, a proteasome subunit that is abundant in cTECs and not detected in other cell types, including mTECs. By crossing ß5t-Cre knock-in mice with loxP-dependent GFP reporter mice, we found that ß5t-Cre-mediated recombination occurs specifically in TECs but not in any other cell types in the mouse. Surprisingly, in addition to cTECs, ß5t-Cre-loxP-mediated GFP expression was detected in almost all mTECs. These results indicate that the majority of mTECs, including autoimmune regulator-expressing mTECs, are derived from ß5t-expressing progenitor cells.

MicroRNAs control the maintenance of thymic epithelia and their competence for T lineage commitment and thymocyte selection.

Thymic epithelial cells provide unique cues for the lifelong selection and differentiation of a repertoire of functionally diverse T cells. Rendered microRNA (miRNA) deficient, these stromal cells in the mouse lose their capacity to instruct the commitment of hematopoietic precursors to a T cell fate, to effect thymocyte positive selection, and to achieve promiscuous gene expression required for central tolerance induction. Over time, the microenvironment created by miRNA-deficient thymic epithelia assumes the cellular composition and structure of peripheral lymphoid tissue, where thympoiesis fails to be supported. These findings emphasize a global role for miRNA in the maintenance and function of the thymic epithelial cell scaffold and establish a novel mechanism how these cells control peripheral tissue Ag expression to prompt central immunological tolerance.

Tratamento do hirsutismo com acetato de ciproterona e estrógenos conjugados em esquema sequencial reverso / Treatment of hirsutism with cyproterone acetate and conjugate estrogens by the reverse sequencial cheme

Os autores trataram 37 mulheres hirsutas com acetato de ciproterona e estrógenos conjugados em esquema sequencial reverso. Os resultados cosméticos foram excelentes e houve diminuiçäo dos níveis plasmáticos de Testosterona, DHEAS e 17 -OHP evaliados por radioimunoensaio

Indice de seletividade da proteinúria como indicador da resposta ao corticosteróide em crianças e adolescentes com síndrome nefrótica idiopática

Foi estudada a correlaçäo entre o índice de seletividade da proteinúria (ISP) e a resposta terapêutica ao corticosteróide em 47 portadores de síndrome nefrótica idiopática (SNI), com idade de 2 a 18 anos, durante um seguimento de 6 anos. O ISP foi determinado pelo método de Cameron (clearance da IgG/clearance da transferina) e classificado em proteinúria altamente seletiva (AS), medianamente seletiva (MS) e pobremente seletiva (PS), de acordo com os valores: < ou = 0,15;0,15 - 0,30 e > 0,30, respectivamente. Antes de iniciar o tratamento com prednisona, 30 pacientes apresentavam AS, 11 MS e 6 PS. Foram corticosensíveis (CS) 87% dos AS, 18% dos MS e nenhuma dos PS. O número de casos que respondeu ao corticosteróide foi significantemente maior no grupo AS do que o observado nos grupos MS e PS (p < 0,001). Näo houve diferença significativa entre MS e PS. Dos 28 pacientes CS, 14(50%) recidivaram a síndrome nefrótica, sendo 12 AS e 2 MS. Dos 12 AS recidivantes, 66,7% mantiveram o padräo da seletividade (AS) e todos evoluíram com funçäo renal normal e boa resposta a prednisona. Os 2 MS mantiveram o clearance de creatinina normal durante todo o seguimento. Três dos 6 pacientes com PS evoluiram para IRC e 2 deles ingressaram em programa de diálise. Esses resultados evidenciam que o ISP pelo método de Cameron, é um bom marcador do tipo de resposta ao corticosteróide e constitui um parâmetro útil no acompanhamento de crianças portadoras de SN