947 resultados para nucleotide repeat
Resumo:
A number of mathematical models for predicting growth and final height outcome have been proposed to enable the clinician to 'individualize' growth-promoting treatment. However, despite optimizing these models, many patients with isolated growth hormone deficiency (IGHD) do not reach their target height. The aim of this study was to analyse the impact of polymorphic genotypes [CA repeat promoter polymorphism of insulin-like growth factor-I (IGF-I) and the -202 A/C promoter polymorphism of IGF-Binding Protein-3 (IGFBP-3)] on variable growth factors as well as final height in severe IGHD following GH treatment. DESIGN, PATIENTS AND CONTROLS: One hundred seventy eight (IGF-I) and 167 (IGFBP-3) subjects with severe growth retardation because of IGHD were studied. In addition, the various genotypes were also studied in a healthy control group of 211 subjects.
Resumo:
Listeria monocytogenes is among the most important food-borne pathogens and is well adapted to persist in the environment. To gain insight into the genetic relatedness and potential virulence of L. monocytogenes strains causing central nervous system (CNS) infections, we used multilocus variable-number tandem-repeat analysis (MLVA) to subtype 183 L. monocytogenes isolates, most from ruminant rhombencephalitis and some from human patients, food, and the environment. Allelic-profile-based comparisons grouped L. monocytogenes strains mainly into three clonal complexes and linked single-locus variants (SLVs). Clonal complex A essentially consisted of isolates from human and ruminant brain samples. All but one rhombencephalitis isolate from cattle were located in clonal complex A. In contrast, food and environmental isolates mainly clustered into clonal complex C, and none was classified as clonal complex A. Isolates of the two main clonal complexes (A and C) obtained by MLVA were analyzed by PCR for the presence of 11 virulence-associated genes (prfA, actA, inlA, inlB, inlC, inlD, inlE, inlF, inlG, inlJ, and inlC2H). Virulence gene analysis revealed significant differences in the actA, inlF, inlG, and inlJ allelic profiles between clinical isolates (complex A) and nonclinical isolates (complex C). The association of particular alleles of actA, inlF, and newly described alleles of inlJ with isolates from CNS infections (particularly rhombencephalitis) suggests that these virulence genes participate in neurovirulence of L. monocytogenes. The overall absence of inlG in clinical complex A and its presence in complex C isolates suggests that the InlG protein is more relevant for the survival of L. monocytogenes in the environment.
Resumo:
Upshaw-Schulman syndrome (USS) is a rarely reported congenital form of thrombotic thrombocytopenic purpura (TTP) that results from mutations in the ADAMTS13 gene. Many USS patients are diagnosed during the second or third trimester of their first pregnancy. We present a patient diagnosed with USS following retinal detachments and intrauterine fetal demise at 34 weeks of gestation. The patient's plasma was tested for ADAMTS13 activity, inhibitor, and antibody. Subsequently, she and her first-degree relatives had ADAMTS13 gene sequencing. Initially, the patient was found to have an ADAMTS13 activity of <5% in the absence of an ADAMTS13 inhibitor (FRETS assay) or antibody (immunoassay). Repeat studies in the months following hospital discharge showed persistent, undetectable ADAMTS13 activity and she was given a clinical diagnosis of USS. Molecular sequencing demonstrated two novel missense mutations in the ADAMTS13 gene: one in the maternal exon 17 (p.Ala690Thr due to nucleotide substitution c.2068 G>A) and another in the paternal exon 22 (p.Arg915Cys due to nucleotide substitution c.2746 C>T). In addition to being compound heterozygous for two ADAMTS13 mutations, the patient also had two maternally inherited single nucleotide polymorphisms: p.P618A (exon 16) and p.A732V (exon 18). Her parents and only sister had normal or near-normal ADAMTS13 activity. Each was heterozygous for one of the novel missense mutations. This case highlights the importance of molecular analysis of the ADAMTS13 gene in patients and family members when the severe ADAMTS13 deficiency does not appear to be autoimmune in nature. J. Clin. Apheresis, 2012. © 2012 Wiley Periodicals, Inc.
Resumo:
The histidine triad nucleotide-binding (Hint2) protein is a mitochondrial adenosine phosphoramidase expressed in liver and pancreas. Its physiological function is unknown. To elucidate the role of Hint2 in liver physiology, the Hint2 gene was deleted. Hint2(-/-) and Hint2(+/+) mice were generated in a mixed C57Bl6/J x 129Sv background. At 20 weeks, the phenotypic changes in Hint2(-/-) relative to Hint2(+/+) mice were an accumulation of hepatic triglycerides, decreased tolerance to glucose, a defective counter-regulatory response to insulin-provoked hypoglycaemia, an increase in plasma interprandial insulin but a decrease in glucose stimulated insulin secretion and defective thermoregulation upon fasting. Leptin mRNA in adipose tissue and plasma leptin were elevated. In mitochondria from Hint2(-/-) hepatocytes, state 3 respiration was decreased, a finding confirmed in HepG2 cells where HINT2 mRNA was silenced. The linked complex II to III electron transfer was decreased in Hint2(-/-) mitochondria, which was accompanied by a lower content of coenzyme Q. HIF-2α expression and the generation of reactive oxygen species were increased. Electron microscopy of mitochondria in Hint2(-/-) mice aged 12 months revealed clustered, fused organelles. The hepatic activities of 3-hydroxyacyl-CoA dehydrogenase short chain and glutamate dehydrogenase (GDH) were decreased by 68% and 60%, respectively, without a change in protein expression. GDH activity was similarly decreased in HINT2-silenced HepG2 cells. When measured in the presence of purified sirtuin 3, latent GDH activity was recovered (126% in Hint2(-/-) vs. 83% in Hint2(+/+) ). This suggests a greater extent of acetylation in Hint2(-/-) than in Hint2(+/+) . Conlusions: Hint2 positively regulates mitochondrial lipid metabolism and respiration, and glucose homeostasis. The absence of Hint2 provokes mitochondrial deformities and a change in the pattern of acetylation of selected proteins. (HEPATOLOGY 2012.).
Resumo:
Click chemistry is a powerful technology for the functionalization of therapeutic proteins with effector moieties, because of its potential for bio-orthogonal, regio-selective, and high-yielding conjugation under mild conditions. Designed Ankyrin Repeat Proteins (DARPins), a novel class of highly stable binding proteins, are particularly well suited for the introduction of clickable methionine surrogates such as azidohomoalanine (Aha) or homopropargylglycine (Hpg), since the DARPin scaffold can be made methionine-free by an M34L mutation in the N-cap which fully maintains the biophysical properties of the protein. A single N-terminal azidohomoalanine, replacing the initiator Met, is incorporated in high yield, and allows preparation of "clickable" DARPins at about 30 mg per liter E. coli culture, fully retaining stability, specificity, and affinity. For a second modification, we introduced a cysteine at the C-terminus. Such DARPins could be conveniently site-specifically linked to two moieties, polyethylene glycol (PEG) to the N-terminus and the fluorophore Alexa488 to the C-terminus. We present a DARPin selected against the epithelial cell adhesion molecule (EpCAM) with excellent properties for tumor targeting as an example. We used these doubly modified molecules to measure binding kinetics on tumor cells and found that PEGylation has no effect on dissociation rate, but slightly decreases the association rate and the maximal number of cell-bound DARPins, fully consistent with our previous model of PEG action obtained in vitro. Our data demonstrate the benefit of click chemistry for site-specific modification of binding proteins like DARPins to conveniently add several functional moieties simultaneously for various biomedical applications.
Resumo:
To determine sirolimus steady-state pharmacokinetics, and to assess the relationship between time-normalized trough sirolimus concentration (C(min,TN)) and evidence of efficacy (rejection and death) and adverse reactions (stomatitis and pneumonia) in liver allograft patients.
Resumo:
Recent research has provided evidence of a link between behavioral measures of social cognition (SC) and neural and genetic correlates. Differences in face processing and variations in the oxytocin receptor (OXTR) gene have been associated with SC deficits and autism spectrum disorder (ASD) traits. Much work has examined the qualitative differences between those with ASD and typically developing (TD) individuals, but very little has been done to quantify the natural variation in ASD-like traits in the typical population. The present study examines this variation in TD children using a multidimensional perspective involving behavior assessment, neural electroencephalogram (EEG) testing, and OXTR genotyping. Children completed a series of neurocognitive assessments, provided saliva samples for sequencing, and completed a face processing task while connected to an EEG. No clear pattern emerged for EEG covariates or genotypes for individual OXTR single nucleotide polymorphisms (SNPs). However, SNPs rs2254298 and rs53576 consistently interacted such that the AG/GG allele combination of these SNPs was associated with poorer performance on neurocognitive measures. These results suggest that neither SNP in isolation is risk-conferring, but rather that the combination of rs2254298(A/G) and rs53576(G/G) confers a deleterious effect on SC across several neurocognitive measures. Copyright 2014. Published by Elsevier Ltd.
Resumo:
Efforts have been made to provide a scientific basis for using environmental services as a conceptual tool to enhance conservation and improve livelihoods in protected mountain areas (MtPAS). Little attention has been paid to participatory research or locals’ concerns as environmental service (ES) users and providers. Such perspectives can illuminate the complex interplay between mountain ecosystems, environmental services and the determinants of human well-being. Repeat photography, long used in geographical fieldwork, is new as a qualitative research tool. This study uses a novel application of repeat photography as a diachronic photo-diary to examine local perceptions of change in ES in Sagarmatha National Park. Results show a consensus among locals on adverse changes to ES, particularly protection against natural hazards, such as landslides and floods, in the UNESCO World Heritage Site. We argue that our methodology could complement biophysical ecosystem assessments in MtPAS, especially since assessing ES, and acting on that, requires integrating diverse stakeholders’ knowledge, recognizing power imbalances and grappling with complex social-ecological systems.
Resumo:
To date, investigations of genetic diversity and the origins of domestication in sheep have utilised autosomal microsatellites and variation in the mitochondrial genome. We present the first analysis of both domestic and wild sheep using genetic markers residing on the ovine Y chromosome. Analysis of a single nucleotide polymorphism (oY1) in the SRY promoter region revealed that allele A-oY1 was present in all wild bighorn sheep (Ovis canadensis), two subspecies of thinhorn sheep (Ovis dalli), European Mouflon (Ovis musimon) and the Barbary (Ammontragis lervia). A-oY1 also had the highest frequency (71.4%) within 458 domestic sheep drawn from 65 breeds sampled from Africa, Asia, Australia, the Caribbean, Europe, the Middle East and Central Asia. Sequence analysis of a second locus, microsatellite SRYM18, revealed a compound repeat array displaying fixed differences, which identified bighorn and thinhorn sheep as distinct from the European Mouflon and domestic animals. Combined genotypic data identified 11 male-specific haplotypes that represented at least two separate lineages. Investigation of the geographical distribution of each haplotype revealed that one (H6) was both very common and widespread in the global sample of domestic breeds. The remaining haplotypes each displayed more restricted and informative distributions. For example, H5 was likely founded following the domestication of European breeds and was used to trace the recent transportation of animals to both the Caribbean and Australia. A high rate of Y chromosomal dispersal appears to have taken place during the development of domestic sheep as only 12.9% of the total observed variation was partitioned between major geographical regions.
Resumo:
Single nucleotide polymorphisms (SNPs) may be used in biodiversity studies and commercial tasks like traceability, paternity testing and selection for suitable genotypes. Twenty-seven SNPs were characterized and genotyped on 250 individuals belonging to eight Italian goat breeds. Multilocus genotype data were used to infer population structure and assign individuals to populations. To estimate the number of groups (K) to test in population structure analysis we used likelihood values and variance of the bootstrap samples, deriving optimal K from a drop in the likelihood and a rise in the variance plots against K.