119 research outputs found

    Prevalence of HCV Infections Among Hemodialysis Patients in Al Gharbiyah Governorate, Egypt

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    Introduction: Hepatitis C virus (HCV) is a significant problem for patients undergoing hemodialysis (HD) treatment. This medical problem has never been studied in Al Gharbiyah Governorate; this study was conductedaiming to estimate the prevalence of anti-HCV positive patients and the incidence of seroconversion in its different HD units.Methods: All 2351 patients maintained on HD in the eight towns of Al Gharbiyah Governorate were interviewed and their anti-HCV status was tested by a third-generation enzyme immunoassay. Patients whotested negative for anti-HCV at the start of the study were re-assessed monthly for HCV seroconversion and at the end of the study all patients were screened for HCV antibodies. Results: At the start of our study in March 2011, we found that 824 out of 2351 patients (35%) were anti-HCV reactive. At the end of study in November 2011, we found that HCV seroconversion occurred in 168 out of1527 patients (11%) who were HCV free at the start of the study. By the end of the study, a total of 42.2% were found to be anti-HCV reactive.Conclusion: The study demonstrated high prevalence of anti-HCV in HD units in Al Gharbiyah Governorate. Similar studies must be conducted in all Egyptian governorates’ HD units to evaluate this major health problem all over Egypt. We also encourage strict application of preventive strategies for HCV infection in all health institutes, especially HD units

    Multi-level selection and the issue of environmental homogeneity

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    In this paper, I identify two general positions with respect to the relationship between environment and natural selection. These positions consist in claiming that selective claims need and, respectively, need not be relativized to homogenous environments. I then show that adopting one or the other position makes a difference with respect to the way in which the effects of selection are to be measured in certain cases in which the focal population is distributed over heterogeneous environments. Moreover, I show that these two positions lead to two different interpretations – the Pricean and contextualist ones – of a type of selection scenarios in which multiple groups varying in properties affect the change in the metapopulation mean of individual-level traits. Showing that these two interpretations stem from different attitudes towards environmental homogeneity allows me to argue: a) that, unlike the Pricean interpretation, the contextualist interpretation can only claim that drift or selection is responsible for the change in frequency of the focal trait in a given metapopulation if details about whether or not group formation is random are specified; b) that the traditional main objection against the Pricean interpretation – consisting in arguing that the latter takes certain side-effects of individual selection to be effects of group selection – is unconvincing. This leads me to suggest that the ongoing debate about which of the two interpretations is preferable should concentrate on different issues than previously thought

    Evolutionary connectionism: algorithmic principles underlying the evolution of biological organisation in evo-devo, evo-eco and evolutionary transitions

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    The mechanisms of variation, selection and inheritance, on which evolution by natural selection depends, are not fixed over evolutionary time. Current evolutionary biology is increasingly focussed on understanding how the evolution of developmental organisations modifies the distribution of phenotypic variation, the evolution of ecological relationships modifies the selective environment, and the evolution of reproductive relationships modifies the heritability of the evolutionary unit. The major transitions in evolution, in particular, involve radical changes in developmental, ecological and reproductive organisations that instantiate variation, selection and inheritance at a higher level of biological organisation. However, current evolutionary theory is poorly equipped to describe how these organisations change over evolutionary time and especially how that results in adaptive complexes at successive scales of organisation (the key problem is that evolution is self-referential, i.e. the products of evolution change the parameters of the evolutionary process). Here we first reinterpret the central open questions in these domains from a perspective that emphasises the common underlying themes. We then synthesise the findings from a developing body of work that is building a new theoretical approach to these questions by converting well-understood theory and results from models of cognitive learning. Specifically, connectionist models of memory and learning demonstrate how simple incremental mechanisms, adjusting the relationships between individually-simple components, can produce organisations that exhibit complex system-level behaviours and improve the adaptive capabilities of the system. We use the term “evolutionary connectionism” to recognise that, by functionally equivalent processes, natural selection acting on the relationships within and between evolutionary entities can result in organisations that produce complex system-level behaviours in evolutionary systems and modify the adaptive capabilities of natural selection over time. We review the evidence supporting the functional equivalences between the domains of learning and of evolution, and discuss the potential for this to resolve conceptual problems in our understanding of the evolution of developmental, ecological and reproductive organisations and, in particular, the major evolutionary transitions

    Socioeconomic position and overweight among adolescents: data from birth cohort studies in Brazil and the UK

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    <p>Abstract</p> <p>Background</p> <p>Developed and developing countries are facing rapid increases in overweight and obesity among children and adolescents. The patterns of overweight/obesity differ by age, sex, rural or urban residence and socioeconomic position (SEP) and vary between and within countries.</p> <p>Methods</p> <p>We investigated patterns of SEP – overweight status association among adolescents from the UK (ALSPAC) and Brazil (the 1982 and 1993 Pelotas birth cohort studies).</p> <p>All analyses were performed separately for males and females. Logistic regression analysis was used to examine the relationships between overweight status and two SEP indicators – family income and maternal education.</p> <p>Results</p> <p>A strong positive association was observed in 11-year-old boys from the 1993 Pelotas cohort, with higher prevalence of overweight among the least poor and among those whose mothers had more years of schooling (<it>x</it><sup>2 </sup>for linear trend p < 0.001). In ALSPAC study higher prevalence of overweight was seen among boys whose mothers had lower educational achievement (<it>x</it><sup>2 </sup>for linear trend p = 0.006). Among 11 year-old girls from 1993 Pelotas cohort study there was a positive association (higher prevalence of overweight in the higher socioeconomic and educational strata, <it>x</it><sup>2 </sup>for linear trend p < 0.001 and p = 0.01, respectively) while an inverse association was found in the ALSPAC study (<it>x</it><sup>2 </sup>for linear trend p < 0.001). Among males from the 1982 cohort study, overweight at 18 years of age showed a positive association with both SEP indicators while among females, the reverse association was found.</p> <p>Conclusion</p> <p>The results of this study demonstrate that the social patterning of overweight varies between and within populations over time. Specific approaches should be developed within populations in order to contain the obesity epidemic and reduce disparities.</p

    Characteristics of mentally ill offenders from 100 psychiatric court reports

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    <p>Abstract</p> <p>Background</p> <p>There is an increasing probability that the psychiatrist will, willingly or not, come into contact with mentally ill offenders in the course of their practice. There are increasing rates of violence, substance abuse and other psychiatric disorders that are of legal importance. Therefore, the aim of this work was to investigate the rates of different mental disorders in 100 court reports and to investigate the characteristics of mentally ill offenders.</p> <p>Methods</p> <p>All cases referred from different departments of the legal system to the forensic committee for assessment of legal accountability over 13-months duration were included. A specially designed form was prepared for data collection. Cases were classified into five groups: murder, robbery, financial offences, violent and simple offences and a group for other offences. Data were subjected to statistical analysis and comparisons between different groups of subjects were performed by analysis of variance (ANOVA).</p> <p>Results</p> <p>Men constituted 93% of cases. In all, 73% of offenders were younger than 40 years old. Schizophrenia cases made up 13% of the total, substance related cases constituted 56% and amphetamine cases alone made up 21%; 10% of cases were antisocial personality disorders, and 51% of cases were classified as having a low education level. Unemployment was found in 34% of cases. The final decision of the forensic committee was full responsibility in 46% of cases and partial responsibility in 11% of cases, with 33% considered non-responsible. A total of 58% of cases had had contact with psychiatric healthcare prior to the offence and in 9% of cases contact had been in the previous 12 weeks. A history of similar offences was found in 32% of cases. In all, 14% of the offences were murders, 8% were sexual crimes, and 31% were violent/simple crimes.</p> <p>Conclusions</p> <p>The ability of the legal system to detect cases was good, while the ability of the healthcare system to predict crimes and offences was weak, as 58% of cases had had previous contact with the healthcare system previously. Substance abuse, especially amphetamine abuse, played an important role.</p

    Evolvable Neuronal Paths: A Novel Basis for Information and Search in the Brain

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    We propose a previously unrecognized kind of informational entity in the brain that is capable of acting as the basis for unlimited hereditary variation in neuronal networks. This unit is a path of activity through a network of neurons, analogous to a path taken through a hidden Markov model. To prove in principle the capabilities of this new kind of informational substrate, we show how a population of paths can be used as the hereditary material for a neuronally implemented genetic algorithm, (the swiss-army knife of black-box optimization techniques) which we have proposed elsewhere could operate at somatic timescales in the brain. We compare this to the same genetic algorithm that uses a standard ‘genetic’ informational substrate, i.e. non-overlapping discrete genotypes, on a range of optimization problems. A path evolution algorithm (PEA) is defined as any algorithm that implements natural selection of paths in a network substrate. A PEA is a previously unrecognized type of natural selection that is well suited for implementation by biological neuronal networks with structural plasticity. The important similarities and differences between a standard genetic algorithm and a PEA are considered. Whilst most experiments are conducted on an abstract network model, at the conclusion of the paper a slightly more realistic neuronal implementation of a PEA is outlined based on Izhikevich spiking neurons. Finally, experimental predictions are made for the identification of such informational paths in the brain

    Studying Language Change Using Price Equation and Pólya-urn Dynamics

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    Language change takes place primarily via diffusion of linguistic variants in a population of individuals. Identifying selective pressures on this process is important not only to construe and predict changes, but also to inform theories of evolutionary dynamics of socio-cultural factors. In this paper, we advocate the Price equation from evolutionary biology and the Pólya-urn dynamics from contagion studies as efficient ways to discover selective pressures. Using the Price equation to process the simulation results of a computer model that follows the Pólya-urn dynamics, we analyze theoretically a variety of factors that could affect language change, including variant prestige, transmission error, individual influence and preference, and social structure. Among these factors, variant prestige is identified as the sole selective pressure, whereas others help modulate the degree of diffusion only if variant prestige is involved. This multidisciplinary study discerns the primary and complementary roles of linguistic, individual learning, and socio-cultural factors in language change, and offers insight into empirical studies of language change

    Estrogen regulation of apoptosis: how can one hormone stimulate and inhibit?

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    The link between estrogen and the development and proliferation of breast cancer is well documented. Estrogen stimulates growth and inhibits apoptosis through estrogen receptor-mediated mechanisms in many cell types. Interestingly, there is strong evidence that estrogen induces apoptosis in breast cancer and other cell types. Forty years ago, before the development of tamoxifen, high-dose estrogen was used to induce tumor regression of hormone-dependent breast cancer in post-menopausal women. While the mechanisms by which estrogen induces apoptosis were not completely known, recent evidence from our laboratory and others demonstrates the involvement of the extrinsic (Fas/FasL) and the intrinsic (mitochondria) pathways in this process. We discuss the different apoptotic signaling pathways involved in E2 (17β-estradiol)-induced apoptosis, including the intrinsic and extrinsic apoptosis pathways, the NF-κB (nuclear factor-kappa-B)-mediated survival pathway as well as the PI3K (phosphoinositide 3-kinase)/Akt signaling pathway. Breast cancer cells can also be sensitized to estrogen-induced apoptosis through suppression of glutathione by BSO (L-buthionine sulfoximine). This finding has implications for the control of breast cancer with low-dose estrogen and other targeted therapeutic drugs

    Regional research priorities in brain and nervous system disorders

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    The characteristics of neurological, psychiatric, developmental and substance-use disorders in low-and middle-income countries are unique and the burden that they have will be different from country to country. Many of the differences are explained by the wide variation in population demographics and size, poverty, conflict, culture, land area and quality, and genetics. Neurological, psychiatric, developmental and substance-use disorders that result from, or are worsened by, a lack of adequate nutrition and infectious disease still afflict much of sub-Saharan Africa, although disorders related to increasing longevity, such as stroke, are on the rise. In the Middle East and North Africa, major depressive disorders and post-traumatic stress disorder are a primary concern because of the conflict-ridden environment. Consanguinity is a serious concern that leads to the high prevalence of recessive disorders in the Middle East and North Africa and possibly other regions. The burden of these disorders in Latin American and Asian countries largely surrounds stroke and vascular disease, dementia and lifestyle factors that are influenced by genetics. Although much knowledge has been gained over the past 10 years, the epidemiology of the conditions in low-and middle-income countries still needs more research. Prevention and treatments could be better informed with more longitudinal studies of risk factors. Challenges and opportunities for ameliorating nervous-system disorders can benefit from both local and regional research collaborations. The lack of resources and infrastructure for health-care and related research, both in terms of personnel and equipment, along with the stigma associated with the physical or behavioural manifestations of some disorders have hampered progress in understanding the disease burden and improving brain health. Individual countries, and regions within countries, have specific needs in terms of research priorities.Fil: Ravindranath, Vijayalakshmi. Indian Institute of Science; IndiaFil: Dang, Hoang Minh. Vietnam National University; VietnamFil: Goya, Rodolfo Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Mansour, Hader. University of Pittsburgh; Estados Unidos. Mansoura University; EgiptoFil: Nimgaonkar, Vishwajit L.. University of Pittsburgh; Estados UnidosFil: Russell, Vivienne Ann. University of Cape Town; SudáfricaFil: Xin, Yu. Peking University; Chin
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