42 resultados para Steroid Hydroxylases


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We present three common variable immunodeficiency (CVID) patients with
severe inflammatory bowel disease of unknown aetiology, resistant to steroid
treatment, treated with infliximab.After exclusion of any infection, infliximab
was given at a dose of 5 mg/kg every 4 weeks for a 3 month induction followed
by every 4–8 weeks depending on clinical response. Two of these patients had
predominantly small bowel disease; they both showed clinical response to
infliximab with weight gain and improvement of quality of life scores. The
third patient had large bowel involvement with profuse watery diarrhea; this
patient improved dramatically within 48 hours of having infliximab
treatment. All three patients have been maintained on infliximab treatment
for between 5 and 53 months (mean 37 months) with no evidence of increased
susceptibility to infections in the patients with small bowel disease, although
the third patient developed two urinary tract infections and a herpes zoster
infection following therapy. This is the first small case series to show that
infliximab is a useful addition to current therapy in this rare group of patients
with potentially life threatening enteritis.

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Understanding how elephants respond to potentially stressful events, such as relocation, is important for making informed management decisions. This study followed the relocation of eight Asian elephants from the Cocos (Keeling) Islands to mainland Australia. The first goal of this study was to examine patterns of adrenocortical activity as reflected in three different substrates: serum, urine, and feces. We found that the three substrates yielded very different signals of adrenocortical activity. Fecal glucocorticoid metabolites (FGM) increased as predicted post-transport, but urinary glucocorticoid metabolites (UGM) were actually lower following transport. Serum cortisol levels did not change significantly. We suggest that the differences in FGM and UGM may reflect changes in steroid biosynthesis, resulting in different primary glucocorticoids being produced at different stages of the stress response. Additional studies are needed to more thoroughly understand the signals of adrenocortical activity yielded by different substrates. The second goal was to examine individual variation in patterns of adrenal response. There was a positive correlation between baseline FGM value and duration of post-transfer increase in FGM concentration. Furthermore, an individual's adrenocortical response to relocation was correlated with behavioral traits of elephants. Elephants that were described by keepers as being “curious” exhibited a more prolonged increase in FGM post-transfer, and “reclusive” elephants had a greater increase in FGM values. Future research should investigate the importance of these personality types for the management and welfare of elephants.

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1. Sex allocation theory has received considerable attention, yet the mechanism(s) by which mothers skew offspring sex ratios remain unknown. In birds, females are the heterogametic sex, which potentially gives them control of whether gametes will be male or female. How females might control the sex of the gamete is unclear, but one possibility is that variation in steroid hormones may mediate this process. 2. We experimentally altered circulating levels of corticosterone in female Gouldian finches (Erythrura gouldiae), a species that demonstrates both extreme stress responses and extreme offspring sex ratio biases when breeding with a low-quality (genetically incompatible) partner. 3. During egg production, individual females received both corticosterone and metyrapone (a corticosterone-synthesis inhibitor) implants, in random order, to induce both high and low levels of circulating stress hormones (within physiological limits). 4. We found that females with elevated corticosterone levels produced male-biased sex ratios, but when the same females were treated with metyrapone they produced female-biased offspring sex ratios. 5. These stress responses are adaptive because females constrained to breeding with low-quality males can substantially increase their fitness by overproducing sons. Changes in maternal corticosterone levels during stressful situations, such as the quality of a breeding partner, may provide an endocrine mechanism that can be exploited for strategic sex allocation.

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1.Sex allocation theory has received considerable attention, yet the mechanism(s) by which mothers skew offspring sex ratios remain unknown. In birds, females are the heterogametic sex, which potentially gives them control of whether gametes will be male or female. How females might control the sex of the gamete is unclear, but one possibility is that variation in steroid hormones may mediate this process. 2.We experimentally altered circulating levels of corticosterone in female Gouldian finches (Erythrura gouldiae), a species that demonstrates both extreme stress responses and extreme offspring sex ratio biases when breeding with a low-quality (genetically incompatible) partner. 3.During egg production, individual females received both corticosterone and metyrapone (a corticosterone-synthesis inhibitor) implants, in random order, to induce both high and low levels of circulating stress hormones (within physiological limits). 4.We found that females with elevated corticosterone levels produced male-biased sex ratios, but when the same females were treated with metyrapone they produced female-biased offspring sex ratios. 5.These stress responses are adaptive because females constrained to breeding with low-quality males can substantially increase their fitness by overproducing sons. Changes in maternal corticosterone levels during stressful situations, such as the quality of a breeding partner, may provide an endocrine mechanism that can be exploited for strategic sex allocation.

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The aim of this study was to examine whether parenting behaviors are associated with child nutrition amongst pre-school children receiving treatment for acute lymphoblastic leukemia (ALL), and to determine whether this association differs from that observed amongst a healthy population. Participants were 73 parents of children aged 2–6 years. The children were either a) receiving treatment for ALL (n = 43), or b) had no major medical history (n = 30). Participants completed psychometrically validated questionnaires that assessed parenting behaviors and child diet. Increased parental overprotection was associated with higher fruit and vegetable consumption for the control group but lower fruit and vegetable consumption for the ALL group. Parental overprotection, inconsistent discipline and emotional feeding were positively associated with non-core (“junk”) food consumption for the ALL group, particularly those who had recently received steroid treatment. To the best of our knowledge, this is the first study to show that certain parenting behaviors may be associated with poor nutrition during treatment for ALL. In light of these results, parenting interventions, specifically targeting parenting behaviors such as assertive discipline, may be a mechanism for nutrition promotion amongst this vulnerable group.

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INTRODUCTION AND AIM: To understand health service access and needs of people who use performance and image enhancing drugs (PIED) in regional Queensland. DESIGN AND METHODS: Semi-structured interviews were conducted with 21 people (n = 19 men) who reported the use of a range of PIEDs, including anabolic-androgenic steroids, human chorionic gonadotropin, growth hormone, clenbuterol, tamoxifen, insulin and peptides. RESULTS: Participants reported accessing a range of services, including needle and syringe programs and pharmacies, for sterile injecting equipment. While PIEDs users attributed some stigma to needle and syringe programs, they were seen as an important service for injecting equipment. Participants reported receiving either positive care from health-care providers, such as general practitioners (GP), or having negative experiences due to the stigma attached with PIED use. Few participants reported disclosing their PIED use to their GP not only because of the concerns that their GP would no longer see them but also because they felt their GP was not knowledgeable about these substances. DISCUSSION AND CONCLUSION: Participants in the study reported no difficulty in accessing health services based on living in a regional area, with their concern focused more upon how they were viewed and treated by service staff. [Dunn M, Henshaw R, Mckay F. H. Do performance and image enhancing drug users in regional Queensland experience difficulty accessing health services? Drug Alcohol Rev 2015;00:000-000].

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The means by which stress influences reproduction is not clearly understood, but may involve a number of endocrine, paracrine and neural systems. Stress impacts on the reproductive axis at the hypothalamus (to affect GnRH secretion) and the pituitary gland (to affect gonadotrophin secretion), with direct effects on the gonads being of less importance. Different stressors have different effects and there are differences in response to short- and long-term stress. Many short-term stresses fail to affect reproduction and there are reports of stimulatory effects of some 'stressors'. There are species differences in the way that specific stressors affect reproduction. Sex differences in the effects of a particular stressor have been delineated and these may relate to effects of stress at different levels of the hypothalamo-pituitary axis. The significance of stress-induced secretion of cortisol varies with species. In some instances, there appears to be little impact of short-term increases in cortisol concentrations and protracted increases in plasma concentration seem to be required before any deleterious effect on reproduction is apparent. Issues of sex, sex steroid status, type of stressor and duration of stress need to be considered to improve understanding of this issue.

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Classic physiology studies dating to the 1930s demonstrate that moderate or transient glucocorticoid (GC) exposure improves muscle performance. The ergogenic properties of GCs are further evidenced by their surreptitious use as doping agents by endurance athletes and poorly understood efficacy in Duchenne muscular dystrophy (DMD), a genetic muscle-wasting disease. A defined molecular basis underlying these performance-enhancing properties of GCs in skeletal muscle remains obscure. Here, we demonstrate that ergogenic effects of GCs are mediated by direct induction of the metabolic transcription factor KLF15, defining a downstream pathway distinct from that resulting in GC-related muscle atrophy. Furthermore, we establish that KLF15 deficiency exacerbates dystrophic severity and muscle GC-KLF15 signaling mediates salutary therapeutic effects in the mdx mouse model of DMD. Thus, although glucocorticoid receptor (GR)-mediated transactivation is often associated with muscle atrophy and other adverse effects of pharmacologic GC administration, our data define a distinct GR-induced gene regulatory pathway that contributes to therapeutic effects of GCs in DMD through proergogenic metabolic programming.

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Understanding the mechanisms that afford invasive species their ecological success as important agents of global change is key to addressing their biodiversity impacts. Species invasions that occur on small islands are especially detrimental and suggest that invaders intensify their ecological impacts by exploiting novel ecological functions. However, it remains unknown whether such strong impacts are also a consequence of an invader's indirect effect (e.g. causing physiological stress or reproductive failure) on island species. Therefore, it is valuable to quantify the physiological mechanisms through which invasive species can exert indirect effects on the performance, and ultimately the fitness of island endemics. In this study, we investigated whether the invasive cane toad (Rhinella marina) caused indirect competitive impacts on the endemic Fijian ground frog (Platymantis vitiana) on the small (60 ha) Viwa Island, Fiji. We used large (4 × 10 000 m2), natural and replicated enclosures to monitor ground frog stress hormone levels, reproductive hormone cycle, body condition, breeding and survival in the presence/absence of the cane toad. We conducted monthly sampling to analyse annual patterns in testosterone for males, estradiol and progesterone for females, corticosterone for both sexes and body condition of ground frogs in replicated enclosures or natural habitats with high/low cane toad densities. We also measured survival and reproductive success of ground frogs in enclosures. Results showed that in both enclosures and natural habitats with high cane toad densities, ground frogs had a significant reduction in body condition, increased urinary corticosterone metabolites and suppressed sex steroid metabolites. Most importantly, annual field surveys showed significant reduction in ground frog reproductive success (fewer eggs were laid in enclosures with toads present); however, survival was not severely reduced. Our study clearly demonstrated that on small islands, invasive species may exploit broader ecological roles with strong indirect effects that amplify their impacts beyond those seen on continents. Overall, the effects of cane toad competition had the capacity to strongly reduce ground frog reproductive success. We strongly advocate management actions that either minimize invasion or limit the strength of invasive-native species interactions (e.g. through habitat conservation) to prevent further extinctions on islands.

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Linoleic acid (LA) is a major constituent of low-density lipoproteins. An essential fatty acid, LA is a polyunsaturated fatty acid, which is oxidised by endogenous enzymes and reactive oxygen species in the circulation. Increased levels of low-density lipoproteins coupled with oxidative stress and lack of antioxidants drive the oxidative processes. This results in synthesis of a range of oxidised derivatives, which play a vital role in regulation of inflammatory processes. The derivatives of LA include, hydroxyoctadecadienoic acids, oxo-​octadecadienoic acids, epoxy octadecadecenoic acid and epoxy-keto-octadecenoic acids. In this review, we examine the role of LA derivatives and their actions on regulation of inflammation relevant to metabolic processes associated with atherogenesis and cancer. The processes affected by LA derivatives include, alteration of airway smooth muscles and vascular wall, affecting sensitivity to pain, and regulating endogenous steroid hormones associated with metabolic syndrome. LA derivatives alter cell adhesion molecules, this initial step, is pivotal in regulating inflammatory processes involving transcription factor peroxisome proliferator-activated receptor pathways, thus, leading to alteration of metabolic processes. The derivatives are known to elicit pleiotropic effects that are either beneficial or detrimental in nature hence making it difficult to determine the exact role of these derivatives in the progress of an assumed target disorder. The key may lie in understanding the role of these derivatives at various stages of development of a disorder. Novel pharmacological approaches in altering the synthesis or introduction of synthesised LA derivatives could possibly help drive processes that could regulate inflammation in a beneficial manner. Chemical Compounds: Linoleic acid (PubChem CID: 5280450), 9- hydroxyoctadecadienoic acid (PubChem CID: 5312830), 13- hydroxyoctadecadienoic acid (PubChem CID: 6443013), 9-oxo-​octadecadienoic acid (PubChem CID: 3083831), 13-oxo-​octadecadienoic acid (PubChem CID: 4163990), 9,10-epoxy-12-octadecenoate (PubChem CID: 5283018), 12,13-epoxy-9-keto-10- trans -octadecenoic acid (PubChem CID: 53394018), Pioglitazone (PubChem CID: 4829).

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Environmental temperature has profound effects on animal physiology, ecology, and evolution. Glucocorticoid (GC) hormones, through effects on phenotypic performance and life history, provide fundamental vertebrate physiological adaptations to environmental variation, yet we lack a comprehensive understanding of how temperature influences GC regulation in vertebrates. Using field studies and metaand comparative phylogenetic analyses, we investigated how acute change and broadscale variation in temperature correlated with baseline and stress-induced GC levels. Glucocorticoid levels were found to be temperature and taxon dependent, but generally, vertebrates exhibited strong positive correlations with acute changes in temperature. Furthermore, reptile baseline, bird baseline, and capture stressinduced GC levels to some extent covaried with broadscale environmental temperature. Thus, vertebrate GC function appears clearly thermally influenced. However, we caution that lack of detailed knowledge of thermal plasticity, heritability, and the basis for strong phylogenetic signal in GC responses limits our current understanding of the role of GC hormones in species’ responses to current and future climate variation.

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BACKGROUND: Perinatal depression has a significant impact on both mother and child. However, the influence of hormonal changes during pregnancy and the postpartum period remains unclear. This article provides a systematic review of studies examining the effects of maternal cortisol function on perinatal depression. METHOD: A systematic search was conducted of six electronic databases for published research on the relationship between cortisol and perinatal depression. The databases included; MEDLINE complete, PsychINFO, SCOPUS, Psychology and Behavioural Sciences, Science Direct and EBSCO, for the years 1960 to May 2015. Risk of bias was assessed and data extraction verified by two investigators. RESULTS: In total, 47 studies met criteria and studies showed considerable variation in terms of methodology including sample size, cortisol assays, cortisol substrates, sampling processes and outcome measures. Those studies identified as higher quality found that the cortisol awakening response is positively associated with momentary mood states but is blunted in cases of major maternal depression. Furthermore, results indicate that hypercortisolemia is linked to transient depressive states while hypocortisolemia is related to chronic postpartum depression. DISCUSSION AND CONCLUSION: Future research should aim to improve the accuracy of cortisol measurement over time, obtain multiple cortisol samples in a day and utilise diagnostic measures of depression. Future studies should also consider both antenatal and postnatal depression and the differential impact of atypical versus melancholic depression on cortisol levels, as this can help to further clarify the relationship between perinatal depression and maternal cortisol function across pregnancy and the postpartum period.