130 research outputs found
Building the field of health policy and systems research: framing the questions.
In the first of a series of articles addressing the current challenges and opportunities for the development of Health Policy & Systems Research (HPSR), Kabir Sheikh and colleagues lay out the main questions vexing the field
Codes of Fair Competition: The National Recovery Act, 1933-1935, and the Women’s Dress Manufacturing Industry
Controversial issues prevalent in today’s ready-to-wear apparel industry include the right of workers to join unions, the proliferation of sweatshops and sweatshop conditions, and design piracy. The idea of forming codes of conduct to establish criteria of ethical business practices is not new to the apparel industry. Indeed, the women’s dress manufacturing industry discussed and debated codes of fair competition under the New Deal Policies of the National Recovery Act (NRA) of 1933 to 1935. Primary sources for this study included governmental hearings in the establishment of the NRA Dress Code, The New York Times, Women’s Wear Daily, and the Journal of the Patent Office Society. The history of the NRA codes implemented in the U.S. women’s ready-to-wear apparel industry provides an important case study highlighting the difficulties and complexities of creating and achieving industry-wide standard practices through self-regulation. The failure of the NRA demonstrates that even with the joint cooperation of industry, labor, and consumer groups and the backing of the force of law, codes of fair competition proved impossible to enforce
Host Alternation Is Necessary to Maintain the Genome Stability of Rift Valley Fever Virus
Arthropod-borne viruses are transmitted among vertebrate hosts by insect vectors. Unusually, Rift Valley fever virus (RVFV) can also be transmitted by direct contacts of animals/humans with infectious tissues. What are the molecular mechanisms and evolutionary events leading to adopt one mode of transmission rather than the other? Viral replication is implied to be different in a vertebrate host and an invertebrate host. The alternating host cycle tends to limit virus evolution by adopting a compromise fitness level for replication in both hosts. To test this hypothesis, we used a cell culture model system to study the evolution of RVFV. We found that freeing RVFV from alternating replication in mammalian and mosquito cells led to large deletions in the NSs gene carrying the virulence factor. Resulting NSs-truncated viruses were able to protect mice from a challenge with a virulent RVFV. Thus, in nature, virulence is likely maintained by continuous alternating passages between vertebrates and insects. Thereby, depending on the mode of transmission adopted, the evolution of RVFV will be of major importance to predict the outcome of outbreaks
Sequential and Coordinated Actions of c-Myc and N-Myc Control Appendicular Skeletal Development
BACKGROUND: During limb development, chondrocytes and osteoblasts emerge from condensations of limb bud mesenchyme. These cells then proliferate and differentiate in separate but adjacent compartments and function cooperatively to promote bone growth through the process of endochondral ossification. While many aspects of limb skeletal formation are understood, little is known about the mechanisms that link the development of undifferentiated limb bud mesenchyme with formation of the precartilaginous condensation and subsequent proliferative expansion of chondrocyte and osteoblast lineages. The aim of this study was to gain insight into these processes by examining the roles of c-Myc and N-Myc in morphogenesis of the limb skeleton. METHODOLOGY/PRINCIPAL FINDINGS: To investigate c-Myc function in skeletal development, we characterized mice in which floxed c-Myc alleles were deleted in undifferentiated limb bud mesenchyme with Prx1-Cre, in chondro-osteoprogenitors with Sox9-Cre and in osteoblasts with Osx1-Cre. We show that c-Myc promotes the proliferative expansion of both chondrocytes and osteoblasts and as a consequence controls the process of endochondral growth and ossification and determines bone size. The control of proliferation by c-Myc was related to its effects on global gene transcription, as phosphorylation of the C-Terminal Domain (pCTD) of RNA Polymerase II, a marker of general transcription initiation, was tightly coupled to cell proliferation of growth plate chondrocytes where c-Myc is expressed and severely downregulated in the absence of c-Myc. Finally, we show that combined deletion of N-Myc and c-Myc in early limb bud mesenchyme gives rise to a severely hypoplastic limb skeleton that exhibits features characteristic of individual c-Myc and N-Myc mutants. CONCLUSIONS/SIGNIFICANCE: Our results show that N-Myc and c-Myc act sequentially during limb development to coordinate the expansion of key progenitor populations responsible for forming the limb skeleton
Evaluation of Urine CCA Assays for Detection of Schistosoma mansoni Infection in Western Kenya
Although accurate assessment of the prevalence of Schistosoma mansoni is important for the design and evaluation of control programs, the most widely used tools for diagnosis are limited by suboptimal sensitivity, slow turn-around-time, or inability to distinguish current from former infections. Recently, two tests that detect circulating cathodic antigen (CCA) in urine of patients with schistosomiasis became commercially available. As part of a larger study on schistosomiasis prevalence in young children, we evaluated the performance and diagnostic accuracy of these tests—the carbon test strip designed for use in the laboratory and the cassette format test intended for field use. In comparison to 6 Kato-Katz exams, the carbon and cassette CCA tests had sensitivities of 88.4% and 94.2% and specificities of 70.9% and 59.4%, respectively. However, because of the known limitations of the Kato-Katz assay, we also utilized latent class analysis (LCA) incorporating the CCA, Kato-Katz, and schistosome-specific antibody results to determine their sensitivities and specificities. The laboratory-based CCA test had a sensitivity of 91.7% and a specificity of 89.4% by LCA while the cassette test had a sensitivity of 96.3% and a specificity of 74.7%. The intensity of the reaction in both urine CCA tests reflected stool egg burden and their performance was not affected by the presence of soil transmitted helminth infections. Our results suggest that urine-based assays for CCA may be valuable in screening for S. mansoni infections
Tryptophan Scanning Analysis of the Membrane Domain of CTR-Copper Transporters
Membrane proteins of the CTR family mediate cellular copper uptake in all eukaryotic cells and have been shown to participate in uptake of platinum-based anticancer drugs. Despite their importance for life and the clinical treatment of malignancies, directed biochemical studies of CTR proteins have been difficult because high-resolution structural information is missing. Building on our recent 7Å structure of the human copper transporter hCTR1, we present the results of an extensive tryptophan-scanning analysis of hCTR1 and its distant relative, yeast CTR3. The comparative analysis supports our previous assignment of the transmembrane helices and shows that most functionally and structurally important residues are clustered around the threefold axis of CTR trimers or engage in helix packing interactions. The scan also identified residues that may play roles in interactions between CTR trimers and suggested that the first transmembrane helix serves as an adaptor that allows evolutionarily diverse CTRs to adopt the same overall structure. Together with previous biochemical and biophysical data, the results of the tryptophan scan are consistent with a mechanistic model in which copper transport occurs along the center of the trimer
Electromagnetic Field Effect or Simply Stress? Effects of UMTS Exposure on Hippocampal Longterm Plasticity in the Context of Procedure Related Hormone Release
Harmful effects of electromagnetic fields (EMF) on cognitive and behavioural features of humans and rodents have been controversially discussed and raised persistent concern about adverse effects of EMF on general brain functions. In the present study we applied radio-frequency (RF) signals of the Universal Mobile Telecommunications System (UMTS) to full brain exposed male Wistar rats in order to elaborate putative influences on stress hormone release (corticosteron; CORT and adrenocorticotropic hormone; ACTH) and on hippocampal derived synaptic long-term plasticity (LTP) and depression (LTD) as electrophysiological hallmarks for memory storage and memory consolidation. Exposure was computer controlled providing blind conditions. Nominal brain-averaged specific absorption rates (SAR) as a measure of applied mass-related dissipated RF power were 0, 2, and 10 W/kg over a period of 120 min. Comparison of cage exposed animals revealed, regardless of EMF exposure, significantly increased CORT and ACTH levels which corresponded with generally decreased field potential slopes and amplitudes in hippocampal LTP and LTD. Animals following SAR exposure of 2 W/kg (averaged over the whole brain of 2.3 g tissue mass) did not differ from the sham-exposed group in LTP and LTD experiments. In contrast, a significant reduction in LTP and LTD was observed at the high power rate of SAR (10 W/kg). The results demonstrate that a rate of 2 W/kg displays no adverse impact on LTP and LTD, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background. Our findings suggest that UMTS exposure with SAR in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg) cannot be excluded
Rates and Predictors of Treatment Failure in Staphylococcus aureus Prosthetic Joint Infections According to Different Management Strategies: A Multinational Cohort Study—The ARTHR-IS Study Group
Introduction: Guidelines have improved the management of prosthetic joint infections (PJI). However, it is necessary to reassess the incidence and risk factors for treatment failure (TF) of Staphylococcus aureus PJI (SA-PJI) including functional loss, which has so far been neglected as an outcome. Methods: A retrospective cohort study of SA-PJI was performed in 19 European hospitals between 2014 and 2016. The outcome variable was TF, including related mortality, clinical failure and functional loss both after the initial surgical procedure and after all procedures at 18 months. Predictors of TF were identified by logistic regression. Landmark analysis was used to avoid immortal time bias with rifampicin when debridement, antibiotics and implant retention (DAIR) was performed. Results: One hundred twenty cases of SA-PJI were included. TF rates after the first and all surgical procedures performed were 32.8% and 24.2%, respectively. After all procedures, functional loss was 6.0% for DAIR and 17.2% for prosthesis removal. Variables independently associated with TF for the first procedure were Charlson >= 2, haemoglobin 30 kg/m(2) and delay of DAIR, while rifampicin use was protective. For all procedures, the variables associated with TF were haemoglobin < 10 g/dL, hip fracture and additional joint surgery not related to persistent infection. Conclusions: TF remains common in SA-PJI. Functional loss accounted for a substantial proportion of treatment failures, particularly after prosthesis removal. Use of rifampicin after DAIR was associated with a protective effect. Among the risk factors identified, anaemia and obesity have not frequently been reported in previous studies. [GRAPHICS]
Targeted Inactivation of Cerberus Like-2 Leads to Left Ventricular Cardiac Hyperplasia and Systolic Dysfunction in the Mouse
Previous analysis of the Cerberus like 2 knockout (Cerl2(-/-)) mouse revealed a significant mortality during the first day after birth, mostly due to cardiac defects apparently associated with randomization of the left-right axis. We have however, identified Cerl2-associated cardiac defects, particularly a large increase in the left ventricular myocardial wall in neonates that cannot be explained by laterality abnormalities. Therefore, in order to access the endogenous role of Cerl2 in cardiogenesis, we analyzed the embryonic and neonatal hearts of Cerl2 null mutants that did not display a laterality phenotype. Neonatal mutants obtained from the compound mouse line Cer2(-/-)Fundacao para a Ciencia e Tecnologia (FCT); IBB/CBME [PEst-OE/EQB/LA0023/2011]; FCT [SFRH/BD/62081/2009]info:eu-repo/semantics/publishedVersio
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