Kinetics and activation of phospholipase C by P2Y purinergic agonists and guanine nucleotides

Membranes prepared from [3H]inositol-labeled turkey erythrocytes express a phospholipase C that is markedly stimulated by stable analogs of GTP (Harden, T. K., Stephens, L., Hawkins, P. T., and Downes, C. P. (1987) J. Biol. Chem. 262, 9057-9061). We now report that P2-purinergic receptor-mediated regulation of the enzyme occurs in the membrane preparation. The order of potency of a series of ATP and ADP analogs for stimulation of inositol phosphate formation, i.e. 2-methylthioadenosine 5'-triphosphate (2MeSATP) greater than adenosine 5'-O-(2-thiodiphosphate) greater than adenosine 5'-O-(3-thiotriphosphate) greater than ATP greater than 5'-adenylyl imidodiphosphate approximately ADP greater than alpha, beta-methyleneadenosine 5'-triphosphate greater than beta, gamma-methyleneadenosine 5'-triphosphate, was consistent with that for the P2Y-purinergic receptor subtype. Agonist-stimulated effects were completely dependent on the presence of guanine nucleotide. Activation of phospholipase C by guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) occurred with a considerable time lag. The rate of activation followed first order kinetics and was markedly increased by increasing concentrations of a P2Y receptor agonist; in contrast, the rate of activation at a fixed agonist concentration was independent of guanine nucleotide concentration. Addition of guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) prior to addition of agonist and GTP, 5'-guanylyl imidodiphosphate (Gpp(NH)p), or GTP gamma S blocked in a concentration-dependent manner the stimulatory effect of guanine nucleotide. GDP beta S, added subsequent to preactivation of membranes with 2MeSATP and GTP gamma S or Gpp(NH)p had only small inhibitory effects on the rate of inositol phosphate production observed over the subsequent 10 min. In contrast, addition of GDP beta S to GTP-preactivated membranes resulted in a rapid return of enzyme activity to the basal state within 60 s. Taken together, the data are consistent with the idea that P2Y receptor activation increases the rate of exchange of GTP and GTP analogs for GDP on the relevant guanine nucleotide regulatory protein. Once the active enzymic species is formed, hydrolysis of guanine nucleotide reverts the enzyme to the inactive state

Is the Screening Test of the French Version of the Dementia Quality of Life Questionnaire Indispensable?

The aim of this study was to evaluate the usefulness of the screening questions in the French version of the Dementia Quality of Life (DQoL) questionnaire. To assess the psychometric properties of the French DQoL, 155 patients with mild-to-moderate dementia were recruited. Here, we compared the psychometric properties of the instrument between patients who passed the screening test (n = 109) and the whole study population (n = 155). The French DQoL version showed a good test-retest reliability at a 2-week interval (0.95 ≤ intraclass correlation coefficients ≤ 1.0), and an average internal consistency (0.58 ≤ Cronbach's α ≤ 0.87) for the 2 study groups. Significant differences were observed in the 2 groups for 4 dimensions of the DQoL regarding dementia severity (Cornell scale), and for 3 dimensions evaluating depression (MMSE). Convergent validity with the Duke Health Profile revealed many significant correlations between dimensions not only in the 109 patients, but also in the whole study population. Our study demonstrated that patients who failed the screening procedure nonetheless seemed to be able to answer the DQoL questionnaire, the whole study group showing acceptable psychometric properties

Single-stranded genomic architecture constrains optimal codon usage

Viral codon usage is shaped by the conflicting forces of mutational pressure and selection to match host patterns for optimal expression. We examined whether genomic architecture (single- or double-stranded DNA) influences the degree to which bacteriophage codon usage differ from their primary bacterial hosts and each other. While both correlated equally with their hosts' genomic nucleotide content, the coat genes of ssDNA phages were less well adapted than those of dsDNA phages to their hosts' codon usage profiles due to their preference for codons ending in thymine. No specific biases were detected in dsDNA phage genomes. In all nine of ten cases of codon redundancy in which a specific codon was overrepresented, ssDNA phages favored the NNT codon. A cytosine to thymine biased mutational pressure working in conjunction with strong selection against non-synonymous mutations appears be shaping codon usage bias in ssDNA viral genomes

Purification of an AlF4- and G-protein beta gamma-subunit-regulated phospholipase C-activating protein.

A 150-kDa phospholipase C has previously been purified from turkey erythrocytes and has been shown by reconstitution with turkey erythrocyte membranes to be a receptor- and G-protein-regulated enzyme (Morris, A. J., Waldo, G. L., Downes, C.P., and Harden, T. K. (1990) J. Biol. Chem. 265, 13501-13507; Morris, A.J., Waldo, G.L., Downes, C.P., and Harden, T.K. (1990) J. Biol. Chem. 265, 13508-13514). Combination of this 150-kDa protein with phosphoinositide substrate-containing phospholipid vesicles prepared with a cholate extract from purified turkey erythrocyte plasma membranes resulted in conferrence of AlF4- sensitivity to the purified phospholipase C. Guanosine 5'-3-O-(thio)triphosphate also activated the reconstituted phospholipase C in a manner that was inhibited by guanosine 5'-2-O-(thio)-diphosphate. The magnitude of the AlF4- stimulation was increased with increasing amounts of plasma membrane extract, and was also dependent on the concentration of purified phospholipase C. Using reconstitution of AlF4- sensitivity as an assay, the putative G-protein conferring regulation to the 150-kDa phospholipase C was purified to near homogeneity by sequential chromatography over Q-Sepharose, Sephacryl S-300, octyl-Sepharose, hydroxylapatite, and Mono-Q. Reconstituting activity co-purified with an approximately 43-kDa protein identified by silver staining; lesser amounts of a 35-kDa protein was present in the final purified fractions, as was a minor 40-kDa protein. The 43-kDa protein strongly reacted with antiserum against a 12-amino acid sequence found at the carboxyl terminus of Gq and G11, the 35-kDa protein strongly reacted with G-protein beta-subunit antiserum, and the 40-kDa protein reacted with antiserum that recognizes Gi3. Immunoprecipitation of the 43-kDa protein resulted in loss of phospholipase C-stimulating activity of the purified fraction. The idea that this is a phospholipase C-regulating G-protein is further supported by the observation that co-reconstitution of G-protein beta gamma-subunit with the purified phospholipase C-activating fraction resulted in a beta gamma-subunit-dependent inhibition of AlF(4-)-stimulated phospholipase C activity in the reconstituted preparation

Memory for expectation-violating concepts:The effects of agents and cultural familiarity

Previous research has shown that ideas which violate our expectations, such as schema-inconsistent concepts, enjoy privileged status in terms of memorability. In our study, memory for concepts that violate cultural (cultural schema-level) expectations (e.g., "illiterate teacher", "wooden bottle", or "thorny grass") versus domain-level (ontological) expectations (e.g., "speaking cat", "jumping maple", or "melting teacher") was examined. Concepts that violate cultural expectations, or counter-schematic, were remembered to a greater extent compared with concepts that violate ontological expectations and with intuitive concepts (e.g., "galloping pony", "drying orchid", or "convertible car"), in both immediate recall, and delayed recognition tests. Importantly, concepts related to agents showed a memory advantage over concepts not pertaining to agents, but this was true only for expectation-violating concepts. Our results imply that intuitive, everyday concepts are equally attractive and memorable regardless of the presence or absence of agents. However, concepts that violate our expectations (cultural-schema or domain-level) are more memorable when pertaining to agents (humans and animals) than to non-agents (plants or objects/artifacts). We conclude that due to their evolutionary salience, cultural ideas which combine expectancy violations and the involvement of an agent are especially memorable and thus have an enhanced probability of being successfully propagated. © 2014 Porubanova et al

Joint synthesis of conditionally related multiple outcomes makes better use of data than separate meta-analyses

Background: When there are structural relationships between outcomes reported in different trials, separate analyses of each outcome do not provide a single coherent analysis, which is required for decision-making. For example, trials of intrapartum anti-bacterial prophylaxis (IAP) to prevent early onset group B streptococcal (EOGBS) disease can report three treatment effects: the effect on bacterial colonisation of the newborn, the effect on EOGBS, and the effect on EOGBS conditional on newborn colonisation. These outcomes are conditionally related, or nested, in a multi-state model. This paper shows how to exploit these structural relationships, providing a single coherent synthesis of all the available data, while checking to ensure that different sources of evidence are consistent. Results: Overall, the use of IAP reduces the risk of EOGBS (RR: 0.03; 95% Credible Interval (CrI): 0.002-0.13). Most of the treatment effect is due to the prevention of colonisation in newborns of colonised mothers (RR: 0.08, 95% CrI: 0.04-0.14). Node-splitting demonstrated that the treatment effect calculated using only direct evidence was consistent with that predicted from the remaining evidence (p=0.15). The findings accorded with previously published separate meta-analyses of the different outcomes, once these are re-analysed correctly accounting for zero cells. Conclusion: Multiple outcomes should be synthesised together where possible, taking account of their structural relationships. This generates an internally coherent analysis, suitable for decision making, in which estimates of each of the treatment effects are based on all available evidence (direct and indirect). Separate meta-analyses of each outcome have none of these properties

Qualidade de vida nas pessoas com esquizofrenia: a influência das características sociodemográficas e clínicas e da satisfação com o suporte social

Objective: To evaluate the relationship of sociodemographic and clinical characteristics and satisfaction with social support with the quality of life of schizophrenic patients. Methodology: This study included a sample of 268 participants. An interview was conducted to obtain sociodemographic and clinical data, supplemented with two assessment tools used to evaluate quality of life (World Health Organization Quality of Life instrument-Abbreviated version – WHOQOL-Bref) and satisfaction with social support (Social Support Satisfaction Scale – SSSS). Descriptive and inferential analyses were performed. Results: Most individuals were male (63.4%), with a mean age of 45.4 years, single (85.4%), living with their family (62.3%) and unemployed (90.3%). As for clinical characteristics, most had the disease for less than 20 years (50.7%), and 55.6% had at least one hospitalization within the last 5 years. Being employed and having had no hospitalization within the last 5 years were positively correlated with one or more WHOQOL-Bref domains. The results of the variables intimacy (p<0.001) and satisfaction with friends (p<0.001) were independently related to the total WHOQOL-Bref score. Conclusion: Having a job, having had no hospitalization within the last 5 years and having greater satisfaction with social support are factors that positively influence quality of life among schizophrenics. It is therefore crucial that the psychosocial rehabilitation of patients with schizophrenia take these factors into account, increasing the support network, preventing relapses and promoting occupational activities.Objetivo: Avaliar a relação entre as características sociodemográficas e clínicas e a satisfação com o suporte social com a qualidade de vida dos doentes com esquizofrenia. Métodos: A amostra do estudo é de 268 participantes. Foi realizada uma entrevista para obter os dados sociodemográficos e clínicos e aplicados dois questionários para avaliar a qualidade de vida (World Health Organization Quality of Life instrument-Abbreviated version – WHOQOL-Bref) e a satisfação com o suporte social (Escala de Satisfação com o Suporte Social – ESSS). Foram efetuadas análises descritivas e inferenciais. Resultados: A maioria dos indivíduos era do gênero masculino (63,4%), com uma média de idade de 45,4 anos, solteiros (85,4%), vivendo com a família (62,3%) e desempregados (90,3%). Relativamente às características clínicas, 50,7% tinham a doença há menos de 20 anos, e 55,6% estiveram internados pelo menos uma vez nos últimos 5 anos. Os resultados demonstraram que estar empregado e não ter sido internado nos últimos 5 anos estão positivamente relacionados com um ou mais domínios da WHOQOL-Bref. A satisfação com a intimidade (p<0,001) e a satisfação com os amigos (p<0,001) foram independentemente associados ao escore total da WHOQOL-Bref. Conclusão: Ter emprego, não ter hospitalizações nos últimos 5 anos e estar satisfeito com o suporte social são fatores que influenciam positivamente a qualidade de vida dos doentes com esquizofrenia. Por conseguinte, é crucial que esses fatores sejam levados em conta nos programas de reabilitação com o suporte social, aumentando a rede de suporte, evitando recaídas e promovendo atividades ocupacionais.publishe

OSTα deficiency: A disorder with cholestasis, liver fibrosis and congenital diarrhea

Solute carrier family 51 alpha subunit (SLC51A ) encodes the alpha subunit of the heteromeric organic solute transporter alpha–beta (OSTα–OSTβ), an important contributor to intestinal bile acid (BA) reabsorption in the enterohepatic circulation.1, 2 Here, we identified the first case of OSTα deficiency in a child with unexplained elevated liver transaminases, cholestasis, and congenital diarrhea

Predicting consumer biomass, size-structure, production, catch potential, responses to fishing and associated uncertainties in the world's marine ecosystems

Existing estimates of fish and consumer biomass in the world’s oceans are disparate. This creates uncertainty about the roles of fish and other consumers in biogeochemical cycles and ecosystem processes, the extent of human and environmental impacts and fishery potential. We develop and use a size-based macroecological model to assess the effects of parameter uncertainty on predicted consumer biomass, production and distribution. Resulting uncertainty is large (e.g. median global biomass 4.9 billion tonnes for consumers weighing 1 g to 1000 kg; 50% uncertainty intervals of 2 to 10.4 billion tonnes; 90% uncertainty intervals of 0.3 to 26.1 billion tonnes) and driven primarily by uncertainty in trophic transfer efficiency and its relationship with predator-prey body mass ratios. Even the upper uncertainty intervals for global predictions of consumer biomass demonstrate the remarkable scarcity of marine consumers, with less than one part in 30 million by volume of the global oceans comprising tissue of macroscopic animals. Thus the apparently high densities of marine life seen in surface and coastal waters and frequently visited abundance hotspots will likely give many in society a false impression of the abundance of marine animals. Unexploited baseline biomass predictions from the simple macroecological model were used to calibrate a more complex size- and trait-based model to estimate fisheries yield and impacts. Yields are highly dependent on baseline biomass and fisheries selectivity. Predicted global sustainable fisheries yield increases ≈4 fold when smaller individuals (< 20 cm from species of maximum mass < 1kg) are targeted in all oceans, but the predicted yields would rarely be accessible in practice and this fishing strategy leads to the collapse of larger species if fishing mortality rates on different size classes cannot be decoupled. Our analyses show that models with minimal parameter demands that are based on a few established ecological principles can support equitable analysis and comparison of diverse ecosystems. The analyses provide insights into the effects of parameter uncertainty on global biomass and production estimates, which have yet to be achieved with complex models, and will therefore help to highlight priorities for future research and data collection. However, the focus on simple model structures and global processes means that non-phytoplankton primary production and several groups, structures and processes of ecological and conservation interest are not represented. Consequently, our simple models become increasingly less useful than more complex alternatives when addressing questions about food web structure and function, biodiversity, resilience and human impacts at smaller scales and for areas closer to coasts