Semaphorins and Plexins are cognate ligand-receptor families that regulate important steps during nervous system development. The Plexin-B2 receptor is critically involved in neural tube closure and ...cerebellar granule cell development, however, its specific ligands have only been suggested by in vitro studies. Here, we show by in vivo and in vitro analyses that the two Semaphorin-4 family members Sema4C and Sema4G are likely to be in vivo ligands of Plexin-B2. The Sema4C and Sema4G genes are expressed in the developing cerebellar cortex, and Sema4C and Sema4G proteins specifically bind to Plexin-B2 expressing cerebellar granule cells. To further elucidate their in vivo function, we have generated and analyzed Sema4C and Sema4G knockout mouse mutants. Like Plexin-B2−/− mutants, Sema4C−/− mutants reveal exencephaly and subsequent neonatal lethality with partial penetrance. Sema4C−/− mutants that bypass exencephaly are viable and fertile, but display distinctive defects of the cerebellar granule cell layer, including gaps in rostral lobules, fusions of caudal lobules, and ectopic granule cells in the molecular layer. In addition to neuronal defects, we observed in Sema4C−/− mutants also ventral skin pigmentation defects that are similar to those found in Plexin-B2−/− mutants. The Sema4G gene deletion causes no overt phenotype by itself, but combined deletion of Sema4C and Sema4G revealed an enhanced cerebellar phenotype. However, Sema4C/Sema4G double mutants showed overall less severe cerebellar phenotypes than Plexin-B2−/− mutants, indicating that further ligands of Plexin-B2 exist. In explant cultures of the developing cerebellar cortex, Sema4C promoted migration of cerebellar granule cell precursors in a Plexin-B2-dependent manner, supporting the model that a reduced migration rate of granule cell precursors is the basis for the cerebellar defects of Sema4C−/− and Sema4C/Sema4G mutants.
Semaphorins and their receptors, plexins, carry out important functions during development and disease. In contrast to the well-characterized plexin A family, however, very little is known about the ...functional relevance of B-type plexins in organogenesis, particularly outside the nervous system. Here, we demonstrate that plexin B1 and its ligand Sema4d are selectively expressed in epithelial and mesenchymal compartments during key steps in the genesis of some organs. This selective expression suggests a role in epithelial-mesenchymal interactions. Importantly, using the developing metanephros as a model system, we have observed that endogenously expressed and exogenously supplemented Sema4d inhibits branching morphogenesis during early stages of development of the ureteric collecting duct system. Our results further suggest that the RhoA-ROCK pathway, which is activated downstream of plexin B1, mediates these inhibitory morphogenetic effects of Sema4d and suppresses branch-promoting signalling effectors of the plexin B1 signalling complex. Finally, mice that lack plexin B1 show early anomalies in kidney development in vivo. These results identify a novel function for plexin B1 as a negative regulator of branching morphogenesis during kidney development, and suggest that the Sema4d-plexin B1 ligand-receptor pair contributes to epithelial-mesenchymal interactions during organogenesis via modulation of RhoA signalling.
The International Knockout Mouse Consortium (IKMC) has produced a genome-wide collection of 15,000 isogenic targeting vectors for conditional mutagenesis in C57BL/6N mice. Although most of the ...vectors have been used successfully in murine embryonic stem (ES) cells, there remain a set of nearly two thousand genes that have failed to target even after several attempts. Recent attention has turned to the use of new genome editing technology for the generation of mutant alleles in mice. Here, we demonstrate how Cas9-assisted targeting can be combined with the IKMC targeting vector resource to generate conditional alleles in genes that have previously eluded targeting using conventional methods.
Abstract Background HIV-1 RNA is a key parameter for reliable diagnosis and treatment of HIV-1 infection. The determination of HIV-1 RNA reduces the pre-seroconversion period in the diagnosis of ...HIV-1 infection and supports clinical management of HIV-1-infected patients. Objectives and study design The COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test combines automated extraction of total nucleic acids on the COBAS® AmpliPrep Instrument with real-time PCR on the COBAS® TaqMan® Analyzer, thus greatly reducing hands-on time during sample preparation and amplification/detection. The test was evaluated for sensitivity, dynamic range, precision, subtype inclusivity, interfering substances, diagnostic and analytical specificity, as well as correlation with three other commercial tests for HIV-1 RNA quantification. Results The COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test demonstrated an assay sensitivity of 40 copies/mL, a greater than 5 log10 measuring range of 40–1.0E+07 copies/mL (1.6–7.0 log10 ) and a reliable determination of HIV-1 group M and N subtypes in EDTA plasma. Quantification results were highly correlated with those obtained by the COBAS® AMPLICOR® HIV-1 MONITOR Test v1.5, the COBAS® AmpliPrep/COBAS® AMPLICOR® HIV-1 MONITOR Test v1.5 and the VERSANT® HIV-1 RNA 3.0 assay. Conclusions The COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test excellently satisfies the requirements for reliable quantification of HIV-1 RNA in clinical specimens by a broad linear measuring range and a fully automated quantification procedure. It is highly appropriate for therapy monitoring and routine management of HIV-1 infection.
Provider: - Institution: - Data provided by Europeana Collections- München, Technische Universität München, Diss., 2011- All metadata published by Europeana are available free of restriction under ...the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Thyroid cancer is the most common endocrine malignancy. Despite having a good prognosis in the majority of cases, when the tumor is dedifferentiated it does no longer respond to conventional ...treatment with radioactive iodine, the prognosis worsens significantly. Treatment options for advanced, dedifferentiated disease are limited and do not cure the disease. Autophagy, a process of self-digestion in which damaged molecules or organelles are degraded and recycled, has emerged as an important player in the pathogenesis of different diseases, including cancer. The role of autophagy in thyroid cancer pathogenesis is not yet elucidated. However, the available data indicate that autophagy is involved in several steps of thyroid tumor initiation and progression as well as in therapy resistance and therefore could be exploited for therapeutic applications. The present review summarizes the most recent data on the role of autophagy in the pathogenesis of thyroid cancer and we will provide a perspective on how this process can be targeted for potential therapeutic approaches and could be further explored in the context of multimodality treatment in cancer and personalized medicine.
The importance of a sustainable health workforce is increasingly recognised. However, the building of a future health workforce that is responsive to diverse population needs and demographic and ...economic change remains insufficiently understood. There is a compelling argument to be made for a comprehensive research agenda to address the questions. With a focus on Europe and taking a health systems approach, we introduce an agenda linked to the 'Health Workforce Research' section of the European Public Health Association. Six major objectives for health workforce policy were identified: (1) to develop frameworks that align health systems/governance and health workforce policy/planning, (2) to explore the effects of changing skill mixes and competencies across sectors and occupational groups, (3) to map how education and health workforce governance can be better integrated, (4) to analyse the impact of health workforce mobility on health systems, (5) to optimise the use of international/EU, national and regional health workforce data and monitoring and (6) to build capacity for policy implementation. This article highlights critical knowledge gaps that currently hamper the opportunities of effectively responding to these challenges and advising policy-makers in different health systems. Closing these knowledge gaps is therefore an important step towards future health workforce governance and policy implementation. There is an urgent need for building health workforce research as an independent, interdisciplinary and multi-professional field. This requires dedicated research funding, new academic education programmes, comparative methodology and knowledge transfer and leadership that can help countries to build a people-centred health workforce.
In individuals with mammary carcinoma, the most relevant prognostic predictor of distant organ metastasis and clinical outcome is the status of axillary lymph node metastasis. Metastases form ...initially in axillary sentinel lymph nodes and progress via connecting lymphatic vessels into postsentinel lymph nodes. However, the mechanisms of consecutive lymph node colonization are unknown. Through the analysis of human mammary carcinomas and their matching axillary lymph nodes, we show here that intrametastatic lymphatic vessels and bulk tumor cell invasion into these vessels highly correlate with formation of postsentinel metastasis. In an in vitro model of tumor bulk invasion, human mammary carcinoma cells caused circular defects in lymphatic endothelial monolayers. These circular defects were highly reminiscent of defects of the lymphovascular walls at sites of tumor invasion in vivo and were primarily generated by the tumor-derived arachidonic acid metabolite 12S-HETE following 15-lipoxygenase-1 (ALOX15) catalysis. Accordingly, pharmacological inhibition and shRNA knockdown of ALOX15 each repressed formation of circular defects in vitro. Importantly, ALOX15 knockdown antagonized formation of lymph node metastasis in xenografted tumors. Furthermore, expression of lipoxygenase in human sentinel lymph node metastases correlated inversely with metastasis-free survival. These results provide evidence that lipoxygenase serves as a mediator of tumor cell invasion into lymphatic vessels and formation of lymph node metastasis in ductal mammary carcinomas.
Sarcoidosis is believed to represent a genetically primed, abnormal immune response to an antigen exposure or inflammatory trigger, with both genetic and environmental factors playing a role in ...disease onset and phenotypic expression. In a population of firefighters with post-World Trade Center (WTC) 9/11/2001 (9/11) sarcoidosis, we have a unique opportunity to describe the clinical course of incident sarcoidosis during the 15 years postexposure and, on average, 8 years following diagnosis.
Among the WTC-exposed cohort, 74 firefighters with post-9/11 sarcoidosis were identified through medical records review. A total of 59 were enrolled in follow-up studies. For each participant, the World Association of Sarcoidosis and Other Granulomatous Diseases organ assessment tool was used to categorize the sarcoidosis involvement of each organ system at time of diagnosis and at follow-up.
The incidence of sarcoidosis post-9/11 was 25 per 100,000. Radiographic resolution of intrathoracic involvement occurred in 24 (45%) subjects. Lung function for nearly all subjects was within normal limits. Extrathoracic involvement increased, most prominently joints (15%) and cardiac (16%) involvement. There was no evidence of calcium dysmetabolism. Few subjects had ocular (5%) or skin (2%) involvement, and none had beryllium sensitization. Most (76%) subjects did not receive any treatment.
Extrathoracic disease was more prevalent in WTC-related sarcoidosis than reported for patients with sarcoidosis without WTC exposure or for other exposure-related granulomatous diseases (beryllium disease and hypersensitivity pneumonitis). Cardiac involvement would have been missed if evaluation stopped after ECG, 48-h recordings, and echocardiogram. Our results also support the need for advanced cardiac screening in asymptomatic patients with strenuous, stressful, public safety occupations, given the potential fatality of a missed diagnosis.
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