Genetic specification of left-right asymmetry in the diaphragm muscles and their motor innervation.

The diaphragm muscle is essential for breathing in mammals. Its asymmetric elevation during contraction correlates with morphological features suggestive of inherent left-right (L/R) asymmetry. Whether this asymmetry is due to L versus R differences in the muscle or in the phrenic nerve activity is unknown. Here, we have combined the analysis of genetically modified mouse models with transcriptomic analysis to show that both the diaphragm muscle and phrenic nerves have asymmetries, which can be established independently of each other during early embryogenesis in pathway instructed by Nodal, a morphogen that also conveys asymmetry in other organs. We further found that phrenic motoneurons receive an early L/R genetic imprint, with L versus R differences both in Slit/Robo signaling and MMP2 activity and in the contribution of both pathways to establish phrenic nerve asymmetry. Our study therefore demonstrates L-R imprinting of spinal motoneurons and describes how L/R modulation of axon guidance signaling helps to match neural circuit formation to organ asymmetry

Kinetic study of the selective hydrogenation of styrene over a Pd egg-shell composite catalyst

This is a study on the kinetics of the liquid-phase hydrogenation of styrene to ethylbenzene over a catalyst of palladium supported on an inorganic–organic composite. This support has a better mechanical resistance than other commercial supports, e.g. alumina, and yields catalysts with egg-shell structure and a very thin active Pd layer. Catalytic tests were carried out in a batch reactor by varying temperature, total pressure and styrene initial concentration between 353–393 K, 10–30 bar, and 0.26–0.60 mol L−1. Kinetic models were developed on the assumptions of dissociative hydrogen chemisorption and non-negligible adsorption of hydrogen and styrene. Final chemical reaction expressions useful for reactor design were obtained. The models that best fitted the experimental data were those ones that considered the surface reaction as the limiting step. In this sense, a two-step Horiuti–Polanyi working mechanism with half hydrogenation intermediates gave the best fit of the experimental data. The heats of adsorption of styrene and ethylbenzene were also estimated.The authors are gratefully indebted to CONICET, ANPCyT and Universidad Nacional del Litoral for financially sponsoring this research work

Cohabitation : the Pan-America View

In this concluding chapter we reflect on a series of issues of both a methodological and substantive nature encountered in this research project. Firstly, we must realize that the use of individual census records not only opened vast possibilities, but also entails a number of limitations. Secondly, the very large sample sizes allowed for the disaggregation of national trends into far more detailed spatial, ethnic and educational patterns. This, in its turn, allowed us to adopt a "geo-historical" view of the rise of cohabitation for almost the entire American continent, from Alaska to Tierra del Fuego. Furthermore, statistical analyses could be performed at the individual and contextual levels simultaneously. Results show that the effects of social stratification, religion and ethnicity are continuing to be of major importance. This not only holds at the individual level, but at the contextual level as well. Nevertheless, an entirely new wave of change started rolling over the pre-existing patterns from the 1970s onward. These trends are following a firm course, irrespective of the economic ups and downs. The Americas, as opposed to many Asian societies and Africa, are now following in the European footsteps, be it with their own distinct and path-dependent characteristics associated with regionally varying historical antecedents

Redes Sociais e Comportamento Sexual: para uma visão relacional da sexualidade, do risco e da prevenção

Com base num inquérito representativo da população portuguesa entre 18 e 65 anos, realizado em 2007, este estudo investiga o impacto de fatores de rede social sobre os comportamentos sexuais dos indivíduos. Através da percepção normativa dos inquiridos sobre a moral sexual dos seus amigos e familiares e de indicadores relativos à caracterização da rede de confidência sexual, tais como o número, a identidade, o gênero, a idade e o comportamento dos confidentes em matéria de sexualidade e prevenção face ao risco de infecção por DSTs, obtivemos um retrato multidimensional das redes sociais dos indivíduos. A realização de análises de regressão linear e logística permitiu avaliar o impacto preditivo da rede sobre o número de parceiros sexuais, as relações sexuais ocasionais e o uso do preservativo. Os dados mostram que os fatores de rede são importantes para explicar o comportamento sexual dos indivíduos. Redes constituídas por amigos e mais liberais em termos de moral sexual tendem a influenciar o comportamento sexual, levando a um maior experimentalismo, sobretudo no caso das mulheres. Por outro lado, a homologia entre o comportamento sexual dos confidentes e o dos inquiridos é relevante para explicar o recurso ao preservativo nas relações sexuais ocasionais, especialmente no caso dos homens. Tanto numa perspectiva relacional da sexualidade como numa óptica epidemiológica, a análise das redes sociais dos indivíduos constitui um aspecto importante para a compreensão e explicação da variedade de experiências sexuais, mais restritas ou mais plurais, e para os riscos de infecção que daí podem advir

SURF1 deficiency causes demyelinating Charcot-Marie-Tooth disease

Objective: To investigate whether mutations in the SURF1 gene are a cause of Charcot-Marie-Tooth (CMT) disease. Methods: We describe 2 patients from a consanguineous family with demyelinating autosomal recessive CMT disease (CMT4) associated with the homozygous splice site mutation c.107-2A>G in the SURF1 gene, encoding an assembly factor of the mitochondrial respiratory chain complex IV. This observation led us to hypothesize that mutations in SURF1 might be an unrecognized cause of CMT4, and we investigated SURF1 in a total of 40 unrelated patients with CMT4 after exclusion of mutations in known CMT4 genes. The functional impact of c.107-2A>G on splicing, amount of SURF1 protein, and on complex IV activity and assembly was analyzed. Results: Another patient with CMT4 was found to harbor 2 additional SURF1 mutations. All 3 patients with SURF1-associated CMT4 presented with severe childhood-onset neuropathy, motor nerve conduction velocities G mutation produced no normally spliced transcript, leading to SURF1 absence. However, complex IV remained partially functional in muscle and fibroblasts. Conclusions: We found SURF1 mutations in 5% of families (2/41) presenting with CMT4. SURF1 should be systematically screened in patients with childhood-onset severe demyelinating neuropathy and additional features such as lactic acidosis, brain MRI abnormalities, and cerebellar ataxia developing years after polyneuropathy

Performing Amateurism: A Study of Camgirls’ Work

International audienc

Long-Term Potentiation in the CA1 Hippocampus Induced by NR2A Subunit-Containing NMDA Glutamate Receptors Is Mediated by Ras-GRF2/Erk Map Kinase Signaling

BACKGROUND: NMDA-type glutamate receptors (NMDARs) are major contributors to long-term potentiation (LTP), a form of synaptic plasticity implicated in the process of learning and memory. These receptors consist of calcium-permeating NR1 and multiple regulatory NR2 subunits. A majority of studies show that both NR2A and NR2B-containing NMDARs can contribute to LTP, but their unique contributions to this form of synaptic plasticity remain poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we show that NR2A and NR2B-containing receptors promote LTP differently in the CA1 hippocampus of 1-month old mice, with the NR2A receptors functioning through Ras-GRF2 and its downstream effector, Erk Map kinase, and NR2B receptors functioning independently of these signaling molecules. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that NR2A-, but not NR2B, containing NMDA receptors induce LTP in pyramidal neurons of the CA1 hippocampus from 1 month old mice through Ras-GRF2 and Erk. This difference add new significance to the observation that the relative levels of these NMDAR subtypes is regulated in neurons, such that NR2A-containing receptors become more prominent late in postnatal development, after sensory experience and synaptic activity

A metabolic signature for NADSYN1-dependent congenital NAD deficiency disorder

Nicotinamide adenine dinucleotide (NAD) is essential for embryonic development. To date, biallelic loss-of-function variants in 3 genes encoding nonredundant enzymes of the NAD de novo synthesis pathway — KYNU, HAAO, and NADSYN1 — have been identified in humans with congenital malformations defined as congenital NAD deficiency disorder (CNDD). Here, we identified 13 further individuals with biallelic NADSYN1 variants predicted to be damaging, and phenotypes ranging from multiple severe malformations to the complete absence of malformation. Enzymatic assessment of variant deleteriousness in vitro revealed protein domain–specific perturbation, complemented by protein structure modeling in silico. We reproduced NADSYN1-dependent CNDD in mice and assessed various maternal NAD precursor supplementation strategies to prevent adverse pregnancy outcomes. While for Nadsyn1+/– mothers, any B3 vitamer was suitable to raise NAD, preventing embryo loss and malformation, Nadsyn1–/– mothers required supplementation with amidated NAD precursors (nicotinamide or nicotinamide mononucleotide) bypassing their metabolic block. The circulatory NAD metabolome in mice and humans before and after NAD precursor supplementation revealed a consistent metabolic signature with utility for patient identification. Our data collectively improve clinical diagnostics of NADSYN1-dependent CNDD, provide guidance for the therapeutic prevention of CNDD, and suggest an ongoing need to maintain NAD levels via amidated NAD precursor supplementation after birth.</p

Awareness and knowledge of sexually transmitted diseases (STDs) among school-going adolescents in Europe: a systematic review of published literature

Samkange-Zeeb FN, Spallek L, Zeeb H. Awareness and knowledge of sexually transmitted diseases (STDs) among school-going adolescents in Europe: a systematic review of published literature. BMC public health. 2011;11(1): 727.BACKGROUND: Sexually transmitted diseases (STDs) are a major health problem affecting mostly young people, not only in developing, but also in developed countries.We conducted this systematic review to determine awareness and knowledge of school-going male and female adolescents in Europe of STDs and if possible, how they perceive their own risk of contracting an STD. Results of this review can help point out areas where STD risk communication for adolescents needs to be improved. METHODS: Using various combinations of the terms "STD", "HIV", "HPV", "Chlamydia", "Syphilis", "Gonorrhoea", "herpes", "hepatitis B", "knowledge", "awareness", and "adolescents", we searched for literature published in the PubMed database from 01.01.1990 up to 31.12.2010. Studies were selected if they reported on the awareness and/or knowledge of one or more STD among school-attending adolescents in a European country and were published in English or German. Reference lists of selected publications were screened for further publications of interest. Information from included studies was systematically extracted and evaluated. RESULTS: A total of 15 studies were included in the review. All were cross-sectional surveys conducted among school-attending adolescents aged 13 to 20 years. Generally, awareness and knowledge varied among the adolescents depending on gender.Six STDs were focussed on in the studies included in the review, with awareness and knowledge being assessed in depth mainly for HIV/AIDS and HPV, and to some extent for chlamydia. For syphilis, gonorrhoea and herpes only awareness was assessed. Awareness was generally high for HIV/AIDS (above 90%) and low for HPV (range 5.4%-66%). Despite knowing that use of condoms helps protect against contracting an STD, some adolescents still regard condoms primarily as an interim method of contraception before using the pill. CONCLUSION: In general, the studies reported low levels of awareness and knowledge of sexually transmitted diseases, with the exception of HIV/AIDS. Although, as shown by some of the findings on condom use, knowledge does not always translate into behaviour change, adolescents' sex education is important for STD prevention, and the school setting plays an important role. Beyond HIV/AIDS, attention should be paid to infections such as chlamydia, gonorrhoea and syphilis