815 resultados para Reversal of sex
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Two feeding experiments and in vitro hind gut fermentation tests were carried out to study the effect of processing sorghum grain on digestion of starch and on the gastrointestinal (GI) tract environment of the horse. In experiment 1, 12 yearling Australian stock horses were blocked on the basis of sex then randomly divided into four equal groups, each containing one castrated male and two females of approximately the same age and weight. Horses were offered at 0800 and 1500 h, 3 kg medium quality liverseed grass (Urochloa panicoides) hay and 2 kg of either oats (O), dry rolled sorghum (DRS), steam-flaked sorghum (SFS) or expanded sorghum (ES). Lanthanum was used as external solid marker for the measurements of apparent total tract digestibility. Fresh water was available ad libitum. Horses were allowed 18 days to adapt to the diets followed by a 3-day faecal collection period. Digestibility of dry matter (DM), and acid detergent fibre (ADF) were higher (P
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The schizophrenia research community has shared a belief that the incidence of schizophrenia shows little variation. This belief is related to the dogma that schizophrenia affects all individuals equally, regardless of sex, race, or nationality. However, there is now robust evidence that the incidence of schizophrenia is characterized by substantial variability. There is prominent variation in the incidence of schizophrenia between sites. The incidence of schizophrenia is significantly higher in males than in females (male:female ratio = 1.4). Migrants and those living in urban areas have a higher incidence of schizophrenia. The incidence of schizophrenia has fluctuations across time. In addition, the prevalence of schizophrenia is also characterized by prominent variation. The realization that schizophrenia is characterized by rich and informative gradients will serve as a catalyst for future research.
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Research has suggested that semantic processing deficits in Parkinson's disease (PD) are related to striatal dopamine deficiency. As an investigation of the influence of dopamine on semantic activation in PD, 7 participants with PD performed a lexical-decision task when on and off levodopa medication. Seven healthy controls matched to the participants with PD in terms of sex, age, and education also participated in the study. By use of a multipriming paradigm, whereby 2 prime words were presented prior to the target word, semantic priming effects were measured across stimulus onset asynchronies (SOAs) of 250 Ins and 1,200 Ins. The results revealed a similar pattern of priming across SOAs for the control group and the PD participants on medication. In contrast, within-group comparisons revealed that automatic semantic activation was compromised in PD participants when off medication. The implications of these results for the neuromodulatory influence of dopamine on semantic processing in PD are discussed.
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Reduction in levels of sex hormones at menopause in women is associated with two common, major outcomes, the accumulation of white adipose tissue, and the progressive loss of bone because of excess osteoclastic bone resorption exceeding osteoblastic bone formation. Current antiresorptive therapies can reduce osteoclastic activity but have only limited capacity to stimulate osteoblastic bone formation and restore lost skeletal mass. Likewise, the availability of effective pharmacological weight loss treatments is currently limited. Here we demonstrate that conditional deletion of hypothalamic neuropeptide Y2 receptors can prevent ongoing bone loss in sex hormone-deficient adult male and female mice. This benefit is attributable solely to activation of an anabolic osteoblastic bone formation response that counterbalances persistent elevation of bone resorption, suggesting the Y2-mediated anabolic pathway to be independent of sex hormones. Furthermore, the increase in fat mass that typically occurs after ovariectomy is prevented by germ line deletion of Y2 receptors, whereas in male mice body weight and fat mass were consistently lower than wild-type regardless of sex hormone status. Therefore, this study indicates a role for Y2 receptors in the accumulation of adipose tissue in the hypogonadal state and demonstrates that hypothalamic Y2 receptors constitutively restrain osteoblastic activity even in the absence of sex hormones. The increase in bone formation after release of this tonic inhibition suggests a promising new avenue for osteoporosis treatment.
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Purpose: To assess repeatability and reproducibility, to determine normative data, and to investigate the effect of age-related macular disease, compared with normals, on photostress recovery time measured using the Eger Macular Stressometer (EMS). Method: The study population comprised 49 healthy eyes of 49 participants. Four EMS measurements were taken in two sessions separated by 1 h by two practitioners, with reversal of order in the second session. EMS readings were also taken from 17 age-related maculopathy (ARM), and 12 age-related macular degeneration (AMD), affected eyes. Results: EMS readings are repeatable to within ± 7 s. There is a statistically significant difference between controls and ARM affected eyes (t = 2.169, p = 0.045), and AMD affected eyes (t = 2.817, p = 0.016). The EMS is highly specific, and demonstrates sensitivity of 29% for ARM, and 50% for AMD. Conclusions: The EMS may be a useful screening test for ARM, however, direct illumination of the macula of greater intensity and longer duration may yield less variable results. © 2004 The College of Optometrists.
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Weight loss in advanced cancer patients is refractory to conventional nutritional support. This may be due to metabolic changes mediated by proinflammatory cytokines, hormones, and tumor-derived products. We previously showed that a nutritional supplement enriched with fish oil will reverse weight loss in patients with pancreatic cancer cachexia. The present study examines the effect of this supplement on a number of mediators thought to play a role in cancer cachexia. Twenty weight-losing patients with pancreatic cancer were asked to consume a nutritional supplement providing 600 kcal and 2 g of eicosapentaenoic acid per day. At baseline and after 3 wk, patients were weighed and samples were collected to measure serum concentrations of interleukin (IL)-6 and its soluble receptor tumor necrosis factor receptors I and II, cortisol, insulin, and leptin, peripheral blood mononuclear cell production of IL-1 beta, IL-6, and tumor necrosis factor, and urinary excretion of proteolysis inducing factor. After 3 wk of consumption of the fish oil-enriched nutritional supplement, there was a significant fall in production of IL-6 (from median 16.5 to 13.7 ng/ml, P = 0.015), a rise in serum insulin concentration (from 3.3 to 5.0 mU/l, P = 0.0064), a fall in the cortisol-to-insulin ratio (P = 0.0084), and a fall in the proportion of patients excreting proteolysis inducing factor (from 88% to 40%, P = 0.008). These changes occurred in association with weight gain (median 1 kg, P = 0.024). Various mediators of catabolism in cachexia are modulated by administration of a fish oil-enriched nutritional supplement in pancreatic cancer patients. This may account for the reversal of weight loss in patients consuming this supplement.
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Cachexia is a wasting syndrome often associated with malignancy, characterised by alterations in host metabolism and significant catabolism of host adipose tissue and skeletal muscle. The MAC16 murine adenocarcinoma is profoundly cachexigenic, inducing host weight-loss at relatively small tumour burden without the induction of anorexia. A 4DkDa factor capable of inducing lipolysis in vitro via an activation of adenylate cyclase (AC) has been isolated from the MAC16 tumour, and the urine of cachectic cancer patients, using a series of ion exchange and gel exclusion chromatography procedures. This lipid-mobilising factor (LMF) has been demonstrated to stimulate lipolysis in adipocytes dose-dependently via a signal transduction pathway involving, possibly, β3-adrenoceptors. Oral administration of the n-3 polyunsaturated fatty acid (PUFA) eicosapentaenoic acid (EPA) attenuated the progression of cachexia, but not the production of LMF, in MAC16 tumour-bearing mice, and was significantly incorporated into plasma phospholipids, skeletal muscle and adipose tissue. EPA supplemented cancer patients also demonstrated significantly increased plasma EPA concentrations. Decreased plasma membrane AC activity in response to LMF was observed in adipocytes isolated from mice receiving EPA. Incubation in vitro of adipocytes, or plasma membranes, with PUFAs significantly altered membrane fatty acid composition and attenuated the induction of both lipolysis, and AC activity, by LMF. The inhibitory actions of EPA, but not docosahexaenoic acid, are probably the consequence of an interaction with guanine nucleotide binding proteins (G-proteins). Progression of the cachectic state induced an up-regulation of adipocyte membrane expression of stimulatory G-proteins, allied with a concomitant down-regulation of inhibitory G-proteins, thus facilitating the catabolic actions of LMF, implying some tumour-mediated effect. A reversal of such alterations was observed upon oral administration of EPA, suggesting that the primary mechanism of action of this fatty acid is an inhibition of the end organ effects of LMF.
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The effect of cancer cachexia on host metabolism has been studied in mice transplanted with either the MAC16 adenocarcinoma which induces profound loss of host body weight and depletion of lipid stores or, the MAC13 adenocarcinoma which is of the same histological type, but which grows without an effect on host body weight. Oxidation of D-[U-14C]glucose was elevated in both tumour-bearing states irrespective of cachexia, when compared with non tumour-bearing controls. Both the MAC16 and MAC13 tumours in vivo utilised glucose at the expense of the brain, where its use was partially replaced by 3-hydroxybutyrate, a ketone body. Oxidation of both [U-14C]palmitic acid and [1-14C]triolein was significantly increased in MAC16 tumour-bearing animals and decreased in MAC13 tumour-bearing animals when compared with non tumour-bearing controls, suggesting that in cachectic tumour-bearing animals, mobilisation of body lipids is accompanied by an increased utilisation by the host. Weight loss in MAC16 tumour-bearing animals is associated with the production of a lipolytic factor. Injection of this partially purified lipolytic factor induced weight loss in recipient animals which could be maintained over time in tumour-bearing animals. This suggests that the tumour acts as a sink for the free fatty acids liberated as a result of the mobilisatation of adipose stores. Lipids are important as an energy source in cachectic animals because of their high calorific value and because glucose is being diverted away from host tissues to support tumour growth. Their importance is further demonstrated by the evidence of a MAC16 tumour-associated lipolytic factor. This lipolytic factor is the key to understanding the alterations in host metabolism that occur in tumour-induced cachexia, and may provide future alternatives for the reversal of cachexia and the treatment of cancer itself.
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Background Abnormalities in incentive decision making, typically assessed using the Iowa Gambling Task (IGT), have been reported in both schizophrenia (SZ) and bipolar disorder (BD). We applied the Expectancy-Valence (E-V) model to determine whether motivational, cognitive and response selection component processes of IGT performance are differentially affected in SZ and BD. Method Performance on the IGT was assessed in 280 individuals comprising 70 remitted patients with SZ, 70 remitted patients with BD and 140 age-, sex-and IQ-matched healthy individuals. Based on the E-V model, we extracted three parameters, 'attention to gains or loses', 'expectancy learning' and 'response consistency', that respectively reflect motivational, cognitive and response selection influences on IGT performance. Results Both patient groups underperformed in the IGT compared to healthy individuals. However, the source of these deficits was diagnosis specific. Associative learning underlying the representation of expectancies was disrupted in SZ whereas BD was associated with increased incentive salience of gains. These findings were not attributable to non-specific effects of sex, IQ, psychopathology or medication. Conclusions Our results point to dissociable processes underlying abnormal incentive decision making in BD and SZ that could potentially be mapped to different neural circuits. © 2012 Cambridge University Press.
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Background: Age-related macular disease is the leading cause of blind registration in the developed world. One aetiological hypothesis involves oxidation, and the intrinsic vulnerability of the retina to damage via this process. This has prompted interest in the role of antioxidants, particularly the carotenoids lutein and zeaxanthin, in the prevention and treatment of this eye disease. Methods: The aim of this randomised controlled trial is to determine the effect of a nutritional supplement containing lutein, vitamins A, C and E, zinc, and copper on measures of visual function in people with and without age-related macular disease. Outcome measures are distance and near visual acuity, contrast sensitivity, colour vision, macular visual field, glare recovery, and fundus photography. Randomisation is achieved via a random number generator, and masking achieved by third party coding of the active and placebo containers. Data collection will take place at nine and 18 months, and statistical analysis will employ Student's t test. Discussion: A paucity of treatment modalities for age-related macular disease has prompted research into the development of prevention strategies. A positive effect on normals may be indicative of a role of nutritional supplementation in preventing or delaying onset of the condition. An observed benefit in the age-related macular disease group may indicate a potential role of supplementation in prevention of progression, or even a degree reversal of the visual effects caused by this condition.
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Neuroimaging (NI) technologies are having increasing impact in the study of complex cognitive and social processes. In this emerging field of social cognitive neuroscience, a central goal should be to increase the understanding of the interaction between the neurobiology of the individual and the environment in which humans develop and function. The study of sex/gender is often a focus for NI research, and may be motivated by a desire to better understand general developmental principles, mental health problems that show female-male disparities, and gendered differences in society. In order to ensure the maximum possible contribution of NI research to these goals, we draw attention to four key principles—overlap, mosaicism, contingency and entanglement—that have emerged from sex/gender research and that should inform NI research design, analysis and interpretation. We discuss the implications of these principles in the form of constructive guidelines and suggestions for researchers, editors, reviewers and science communicators.
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Christianity has historically incorporated numerous strands of thinking on sexuality; in some cases, problematizing sexuality through the endorsement of celibacy and asceticism while at other historical and contextual moments, marriage and procreation become ideals (Price 2006). Contemporary Christians negotiate many sexual scripts (including ‘secular’ ones), but ‘appropriate’ Christian sexuality is still usually defined in terms of monogamy, the containment of sex within marriage, and heterosexuality. This chapter will explore the attitudes, beliefs and practices toward sexuality of young Christian women and men aged between 18 and 25 and living in the UK, based on a qualitative and quantitative research project entitled Religion, Youth and Sexuality: A Multi-faith Exploration, which utilized questionnaires, in-depth interviews and video diaries. The chapter will consider the variations in attitude between young people from different Christian denominations in relation to three themes: sex outside of marriage, celibacy and monogamy.
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Tonic conductance mediated by extrasynaptic GABAA receptors has been implicated in the modulation of network oscillatory activity. Using an in vitro brain slice to produce oscillatory activity and a kinetic model of GABAA receptor dynamics, we show that changes in tonic inhibitory input to fast spiking interneurons underlie benzodiazepine-site mediated modulation of neuronal network synchrony in rat primary motor cortex. We found that low concentrations (10 nM) of the benzodiazepine site agonist, zolpidem, reduced the power of pharmacologically-induced beta-frequency (15–30 Hz) oscillatory activity. By contrast, higher doses augmented beta power. Application of the antagonist, flumazenil, also increased beta power suggesting endogenous modulation of the benzodiazepine binding site. Voltage-clamp experiments revealed that pharmacologically-induced rhythmic inhibitory postsynaptic currents were reduced by 10 nM zolpidem, suggesting an action on inhibitory interneurons. Further voltage -clamp studies of fast spiking cells showed that 10 nM zolpidem augmented a tonic inhibitory GABAA receptor mediated current in fast spiking cells whilst higher concentrations of zolpidem reduced the tonic current. A kinetic model of zolpidem-sensitive GABAA receptors suggested that incubation with 10 nM zolpidem resulted in a high proportion of GABAA receptors locked in a kinetically slow desensitized state whilst 30 nM zolpidem favoured rapid transition into and out of desensitized states. This was confirmed experimentally using a challenge with saturating concentrations of GABA. Selective modulation of an interneuron-specific tonic current may underlie the reversal of cognitive and motor deficits afforded by low-dose zolpidem in neuropathological states.
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This article uses a research project into the online conversations of sex offenders and the children they abuse to further the arguments for the acceptability of experimental work as a research tool for linguists. The research reported here contributes to the growing body of work within linguistics that has found experimental methods to be useful in answering questions about representation and constraints on linguistic expression (Hemforth 2013). The wider project examines online identity assumption in online paedophile activity and the policing of such activity, and involves dealing with the linguistic analysis of highly sensitive sexual grooming transcripts. Within the linguistics portion of the project, we examine theories of idiolect and identity through analysis of the ‘talk’ of perpetrators of online sexual abuse, and of the undercover officers that must assume alternative identities in order to investigate such crimes. The essential linguistic question in this article is methodological and concerns the applicability of experimental work to exploration of online identity and identity disguise. Although we touch on empirical questions, such as the sufficiency of linguistic description that will enable convincing identity disguise, we do not explore the experimental results in detail. In spite of the preference within a range of discourse analytical paradigms for ‘naturally occurring’ data, we argue that not only does the term prove conceptually problematic, but in certain contexts, and particularly in the applied forensic context described, a rejection of experimentally elicited data would limit the possible types and extent of analyses. Thus, it would restrict the contribution that academic linguistics can make in addressing a serious social problem.
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Sex work is a subject of significant contestation across academic disciplines, as well as within legal, medical, moral, feminist, political and socio-cultural discourses. A large body of research exists, but much of this focuses on the sale of sex by women to men and ignores other performances, practices, meanings and embodiments in the contemporary sex industry. A queer agenda is important in order to challenge hetero-centric gender norms and to develop new insights into how gender, sex, power, crime, work, migration, space/place, health and intimacy are understood in the context of commercial sexual encounters. Queer Sex Work explores what it might mean to 'be', 'do' and 'think' queer(ly) in the study and practice of commercial sex. It brings together a multiplicity of empirical case studies - including erotic dance venues, online sex working, pornography, grey sexual economies, and BSDM - and offers a variety of perspectives from academic scholars, policy practitioners, activists and sex workers themselves. In so doing, the book advances a queer politics of sex work that aims to disrupt heteronormative logics whilst also making space for different voices in academic and political debates about commercial sex. This unique and multidisciplinary volume will be indispensable for scholars and students of the global sex trade and of gender, sexuality, feminism and queer theory more broadly, as well as policymakers, activists and practitioners interested in the politics and practice of sex work in local, national and international contexts.