991 resultados para Crustacean Endocrinology
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Skin kininogens from bombinid toads encode an array of bradykinin-related peptides and one such kininogen from Bombina maxima also encodes the potent bradykinin B2-receptor antagonist, kinestatin. In order to determine if the skin secretion of the closely-related toad, Bombina orientalis, contained a bradykinin inhibitory peptide related to kinestatin, we screened reverse phase HPLC fractions of defensive skin secretion using a rat tail artery smooth muscle preparation. A fraction was located that inhibited bradykinin-induced relaxation of the preparation and this contained a peptide of 3198.5 Da as determined by MALDI-TOF MS. Automated Edman degradation of this peptide established the identity of a 28-mer as: DMYEIKGFKSAHGRPRVCPPGEQCPIWV, with a disulfide-bridge between Cys18 and Cys24 and an amidated C-terminal Val residue. Peptide DV-28 was found to correspond to residues 133–160 of skin pre-kininogen-2 of B. orientalis that also encodes two copies of (Thr6)-bradykinin. The C-terminal residue, Gly-161, of the precursor open-reading frame, acts as the C-terminal amide donor of mature DV-28. DV-28 amide thus represents a new class of bradykinin inhibitor peptide from amphibian skin secretion.
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Here we report the primary structure of a novel peptide, named helokinestatin-5 (VPPPLQMPLIPR), from the venom of the Gila monster (Heloderma suspectum). Helokinestatin-5 differs in structure from helokinestatin-3 by deletion of a single prolyl residue in the N-terminally located polyproline region. Two different biosynthetic precursors were consistently cloned from a venom-derived cDNA library. The first encoded helokinestatins 1–4 and a single copy of C-type natriuretic peptide, as previously described, whereas the second was virtually identical, lacking only a single prolyl codon as found in the mature attenuated helokinestatin-5 peptide. Helokinestatins 1–3 and 5 were synthesized by solid-phase fmoc chemistry and each synthetic replicate was found to antagonize the relaxation effect induced by bradykinin on rat tail artery smooth muscle. Helokinestatins thus represent a novel family of vasoactive peptides from the venom of helodermatid lizards
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Background: Male infertility is a common cause of reproductive failure in humans. In mice, targeted deletions of the genes coding for FKBP6 or FKBP52, members of the FK506 binding protein family, can result in male infertility. In the case of FKBP52, this reflects an important role in potentiating Androgen Receptor (AR) signalling in the prostate and accessory glands, but not the testis. In infertile men, no mutations of FKBP52 or FKBP6 have been found so far, but the gene for FKBP-like (FKBPL) maps to chromosome 6p21.3, an area linked to azoospermia in a group of Japanese patients.
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CCK receptors represent potential targets in a number of diseases. Knowledge of CCK receptor binding sites is a prerequisite for the understanding of the molecular basis for their ligand recognition, partial agonism, ligand-induced trafficking of signalling. In the current paper, we report studies from our laboratory and others which have provided new data on the molecularbasis of the pharmacology and functioning of CCK1 and CCK2 receptors. It has been shown that: 1) homologous regions of the two receptors are involved in the binding site of CCK, however, positioning of CCK slightly differs in agreement with distinct phannacophores of CCK toward the two receptors and receptor sequence variations; 2) Binding sites of most of non-peptide agonists/ antagonist are buried in the pocket formed by transmembrane helices and overlap that of CCK; Aromatic amino acids within and near the binding site, especially in helix VI, are involved in receptor activation; 4) Like for other members of family A of G-protein coupled receptors, residues of the binding sites as well as of conserved motifs such as E/DRY, NPXXY are crucial for receptor activation. (c) 2007 Elsevier B.V. All rights reserved.
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During the development of PCR primer sets for icrosatellite marker loci from enriched genomic libraries for three squat lobster species from Galatheidae (Decapoda: Anomura); Munida rugosa (Fabricius, 1775), M. sarsi (Huus, 1935), and Galathea strigosa (Linnaeus, 1761) (collectively known as squat lobsters), a number of unforeseen problems were encountered. These included PCR amplification failure, lack of amplification consistency, and the amplification of multiple fragments. Careful examination of microsatellite containing sequences revealed the existence of cryptic repeated elements on presumed unique flanking regions. BLAST analysis of these and other VNTR containing sequences (N 5 252) indicates that these cryptic elements can be grouped into families based upon sequence similarities. The unique features characterising these families suggest that different molecular mechanisms are involved. Of particular relevance is the association of microsatellites with mobile elements. This is the first reported observation of this phenomenon in crustaceans, and it also helps to explain why microsatellite primer development in galatheids has been relatively unsuccessful to date. We suggest a number of steps that can be used to identify similar problems in microsatellite marker development for other species, and also alternative approaches for both marker development and for the study of molecular evolution of species characterised by complex genome organisation. More specifically, we argue that new generation sequencing methodologies, which capitalise on parallel and multiplexed sequencing may pave the way forward for future crustacean research.
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Aims: Pre-pregnancy care optimizes pregnancy outcome in women with pre-gestational diabetes, yet most women enter pregnancy unprepared. We sought to determine knowledge and attitudes of women with Type 1 and Type 2 diabetes of childbearing age towards pre-pregnancy care.
Methods: Twenty-four women (18 with Type 1 diabetes and six with Type 2 diabetes) aged 17–40 years took part in one of four focus group sessions: young nulliparous women with Type 1 diabetes (Group A), older nulliparous women with Type 1 diabetes (Group B), parous women with Type 1 diabetes (Group C) and women with Type 2 diabetes of mixed parity (Group D).
Results: Content analysis of transcribed focus groups revealed that, while women were well informed about the need to plan pregnancy, awareness of the rationale for planning was only evident in parous women or those who had actively sought pre-pregnancy advice. Within each group, there was uncertainty about what pre-pregnancy advice entailed. Despite many women reporting positive healthcare experiences, frequently cited barriers to discussing issues around family planning included unsupportive staff, busy clinics and perceived social stereotypes held by health professionals.
Conclusions: Knowledge and attitudes reported in this study highlight the need for women with diabetes, regardless of age, marital status or type of diabetes, to receive guidance about planning pregnancy in a motivating, positive and supportive manner. The important patient viewpoints expressed in this study may help health professionals determine how best to encourage women to avail of pre-pregnancy care
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Aims/hypothesis: The aim of this study was to investigate the evidence of an increased risk of childhood-onset type 1 diabetes in children born by Caesarean section by systematically reviewing the published literature and performing a meta-analysis with adjustment for recognised confounders.
Methods: After MEDLINE, Web of Science and EMBASE searches, crude ORs and 95% CIs for type 1 diabetes in children born by Caesarean section were calculated from the data reported in each study. Authors were contacted to facilitate adjustments for potential confounders, either by supplying raw data or calculating adjusted estimates. Meta-analysis techniques were then used to derive combined ORs and to investigate heterogeneity between studies.
Results: Twenty studies were identified. Overall, there was a significant increase in the risk of type 1 diabetes in children born by Caesarean section (OR 1.23, 95% CI 1.15-1.32, p<0.001). There was little evidence of heterogeneity between studies (p=0.54). Seventeen authors provided raw data or adjusted estimates to facilitate adjustments for potential confounders. In these studies, there was evidence of an increase in diabetes risk with greater birthweight, shorter gestation and greater maternal age. The increased risk of type 1 diabetes after Caesarean section was little altered after adjustment for gestational age, birth weight, maternal age, birth order, breast-feeding and maternal diabetes (adjusted OR 1.19, 95% CI 1.04-1.36, p=0.01).
Conclusions/interpretation: This analysis demonstrates a 20% increase in the risk of childhood-onset type 1 diabetes after Caesarean section delivery that cannot be explained by known confounders.
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Aim: Flow-mediated dilation (FMD) is a surrogate marker of endothelial function, which has been proposed as a barometer of vascular health. Impaired microvascular response to reactive hyperaemia is thought to be the mechanism behind reduced shear stress and subsequently impaired FMD, which has been associated with cardiovascular events. This study aims to assess the effect of pioglitazone on the vasculature of patients with impaired glucose tolerance (IGT).
Materials and Methods: Forty IGT patients with no cardiovascular disease were compared with 24 healthy age- and sex-matched controls. Endothelial function was assessed using FMD of the brachial artery. Adiponectin (ADN) levels were measured and insulin sensitivity was calculated using homeostasis model assessment of insulin resistance (HOMA-IR). A randomised double-blind placebo-controlled trial of the IGT subjects was then performed, with subjects receiving either pioglitazone 30 mg od or matched placebo for 12 weeks before the measurements were repeated.
Results: The IGT subjects had a significantly impaired FMD compared with the controls (p < 0.001). Diastolic shear stress (DSS) was also significantly reduced in IGT (p = 0.04). High molecular weight (HMW) ADN was significantly lower in the IGT group than in controls (p = 0.03). On analysis of the IGT group after 12 weeks treatment, FMD was significantly increased in the pioglitazone group compared with placebo (p = 0.03) as was endothelium-independent dilation (EID) (p = 0.03). A significant increase in total ADN (p < 0.001), HMW ADN (p < 0.001) and HMW/total ratio (p = 0.001) occurred in the pioglitazone group compared with placebo.
Conclusions: Pioglitazone improved endothelial function in IGT. Treatment with pioglitazone may reduce the risk of cardiovascular disease in this patient group.
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OBJECTOVE - To examine mortality rates and causes of death among subjects diagnosed with type I diabetes aged
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Background: The marked increases in the incidence of type 1 diabetes in recent decades strongly suggest the role of environmental influences. These environmental influences remain largely unknown.
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Aims To determine whether children with infections in early life (recorded routinely in general practice) have a reduced risk of Type 1 diabetes, as would be expected from the hygiene hypothesis.
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OBJECTIVE:Diabetes during pregnancy is a strong risk factor for obesity in the offspring, but the age at which this association becomes apparent is unknown. The purpose of this study was to examine the relation of glycemia during pregnancy with anthropometry in offspring of nondiabetic pregnant women from the Belfast U.K. center of the multinational Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study.
RESEARCH DESIGN AND METHODS: Women from the HAPO Study were invited to participate in follow-up of their offspring aged 2 years. Measurements included height, weight, and thickness of triceps, subscapular, and suprailiac skinfolds. RESULTS: A total of 1,165 offspring (73% of eligible children; 598 boys and 567 girls) were seen from ages 22-30 completed months. The only association that reached statistical significance was between categories of maternal 1-h glucose and BMI Z score =85th percentile at 2 years (P = 0.017). Overall the correlations between maternal glucose during pregnancy and BMI Z score at age 2 years were weak (fasting glucose r = 0.05, P = 0.08; 1-h glucose r = 0.04, P = 0.22; 2-h glucose r = 0.03, P = 0.36; and area under the curve for glucose r = 0.04, P = 0.18).
CONCLUSIONS: This study found little association between maternal glucose during pregnancy and obesity in the offspring at this young age. These findings are not unexpected given that study results for young offspring whose mothers had diabetes during pregnancy were indistinguishable from those for normal offspring at this age. It will be interesting to see whether, as these children age, maternal glucose during pregnancy in the ranges included in the HAPO Study will be associated with obesity in their children. © 2010 by the American Diabetes Association.