916 resultados para enzyme polymorphism
Resumo:
Feathers confer protection against biophysical agents and determine flying ability. The geometry and arrangement of the barbs, together with the keratin and pigments deposited in the feathers, determine the mechanical stability of the vane, and its stiffness and resistance to abrasive agents. In colour-polymorphic species, individuals display alternative colour morphs, which can be associated with different foraging strategies. Each morph may therefore require specific flying abilities, and their feathers may be exposed to different abrasive agents. Feathers of differently coloured individuals may thus have a specific structure, and colour pigments may help resist abrasive agents and improve stiffness. We examined these predictions in the barn owl (Tyto alba), a species for which the ventral body side varies from white to dark reddish pheomelanic, and in the number and size of black spots located at the tip of the feathers. White and reddish birds show different foraging strategies, and the size of black feather spots is associated with several phenotypic attributes. We found that birds displaying a darker reddish coloration on the ventral body side deposit more melanin pigments in their remiges, which also have fewer barbs. This suggests that wear resistance increases with darkness, whereas feathers of lighter coloured birds may bend less easily. Accordingly, individuals displaying a lighter reddish coloration on the ventral body side, and those displaying larger black spots, displayed more black transverse bars on their remiges: as larger-spotted individuals are heavier and longer-winged birds also have more transverse bars, these bars may reduce feather bending when flying. We conclude that differently coloured individuals produce wing feathers of different strengths to adopt alternative behavioural and life history strategies
Resumo:
Codeine is commonly used in North America in the postpartum period for pain associated with episotomyand caesarean section. Analgesic properties of codeine are mainly due to its metabolisation intomorphine (5-10%) via CYP2D6. This enzyme is subject to genetic variability, which can alter theamount of active narcotic excreted into breastmilk. A recent case report highlighted this issue, reportingfatal consequences in a newborn whose mother was taking codeine for episiotomy-related pain (1-2). New-born's blood (post-mortem) and mother's milk showed high morphine concentrations. Genotypeanalysis classified the mother as a CYP2D6 ultrarapid metabolizer, a genotype associated withenhanced formation of morphine from codeine. The authors concluded "clinical and laboratory picturewas consistent with opioid toxicity leading to neonatal death". Subsequent comments expressed reasonnabledoubts on this conclusion, though (3-4). Since, anxiety increased about the safety of codeineduring breastfeeding and genetic screening was proposed as a prevention strategy.STIS position:? Codeine with paracetamol is not a usual pain prescription in the postpartum period in Switzerland.This markedly reduces codeine use during lactation in our country, and may partly explain why webarely collected 3 codeine exposures through breastmilk in 15 years at the STIS (all reported afterabove case's publication and without side effects).? Other centrally acting analgesics are not considered safer (5) than codeine during lactation andrequire close observation for somnolence in both the mother and the infant in case of repeated maternaldosage. A lack of monitoring was salient in the case reported above (1).? If the incidence of CYP2D6 polymorphism (1-10% of individuals in Western Europe) (6) can beconsidered of clinical significance, it is not the exclusive predisposing factor to toxic effects. Healthynewborns can be particularly sensitive to even usual doses of narcotic analgesics because of immaturedrug disposition (7). Conditions leading to impaired clearance or increased susceptibility inthe infant (e.g. preterm birth, metabolic diseases) represent further risk factors for opioid toxicity,regardless of the molecule.In conclusion, when prescribed on a large scale, codein can be rarely associated with adverse drugreactions in breastfed infants (8-9). However, other central acting analgesics cannot be considered asinvariably safer. Therefore, paracetamol and well documented NSAID should be used in 1st choiceduring lactation. In case of severe pain, codeine (with paracetamol) remains an acceptable choice butrequires close monitoring, and breastfeeding mothers should be educated regarding risks related toaccumulation in the newborn. Finally, it is doubtful whether CYP2D6 genetic screening would preventall toxic effects, as other risk factors exist for opioids toxicity
Resumo:
Colorectal cancer is one of the most prevalent cancers in developed countries. However, the genetic factors influencing its appearance remain far from being fully characterized. Recently, a G>A functional transition mapping the 3' untranslated region of the CXCL12 gene (rs1801157) has been found to be under-represented among rectal cancer patients when compared to colon cancer patients from a Swedish series. Here we present the results from an independent analysis of CXCL12 rs1801157 in a larger CRC series of Spanish origin in order to analyse the robustness of this association within a different European population. No significant difference was observed between controls and colon or rectal cancer patients. We were also unable to find a correlation between rs1801157 and different prognostic markers such as metastasis development or disease-free survival time. The epidemiologic data involving CXCL12 rs1801157 in colorectal cancer risk are discussed.
Resumo:
Angiostrongylus costaricensis has a broad geographic distribution spanning from North to South America and the infections of vertebrates with this nematode can result in abdominal complications. Human infections are diagnosed by histological or serological methods because the isolation of larvae from feces is not feasible, as most parasites become trapped in intestinal tissues due to intense eosinophilic inflammation. Because A. costaricensis is difficult to maintain in the laboratory, an immunodiagnostic IgG enzyme-linked immunosorbent assay (ELISA) using antigens from the congeneric Angiostrongylus cantonensis species was evaluated against a panel of serum samples from patients who were histologically diagnosed with A. costaricensis infections. Sera from uninfected individuals and individuals infected with other parasites were used as controls. The sensitivity and specificity of the assay were estimated at 88.4% and 78.7%, respectively. Because the use of purified or cloned antigens has not been established as a reliable diagnostic tool, the use of heterologous antigens may provide a viable alternative for the development of an ELISA-based immunodetection system for the diagnosis of abdominal angiostrongyliasis.
Resumo:
BACKGROUND Temporomandibular disorder (TMD) is a multifactorial syndrome related to a critical period of human life. TMD has been associated with psychological dysfunctions, oxidative state and sexual dimorphism with coincidental occurrence along the pubertal development. In this work we study the association between TMD and genetic polymorphisms of folate metabolism, neurotransmission, oxidative and hormonal metabolism. Folate metabolism, which depends on genes variations and diet, is directly involved in genetic and epigenetic variations that can influence the changes of last growing period of development in human and the appearance of the TMD. METHODS A case-control study was designed to evaluate the impact of genetic polymorphisms above described on TMD. A total of 229 individuals (69% women) were included at the study; 86 were patients with TMD and 143 were healthy control subjects. Subjects underwent to a clinical examination following the guidelines by the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Genotyping of 20 Single Nucleotide Polymorphisms (SNPs), divided in two groups, was performed by multiplex minisequencing preceded by multiplex PCR. Other seven genetic polymorphisms different from SNPs (deletions, insertions, tandem repeat, null genotype) were achieved by a multiplex-PCR. A chi-square test was performed to determine the differences in genotype and allelic frequencies between TMD patients and healthy subjects. To estimate TMD risk, in those polymorphisms that shown significant differences, odds ratio (OR) with a 95% of confidence interval were calculated. RESULTS Six of the polymorphisms showed statistical associations with TMD. Four of them are related to enzymes of folates metabolism: Allele G of Serine Hydoxymethyltransferase 1 (SHMT1) rs1979277 (OR = 3.99; 95%CI 1.72, 9.25; p = 0.002), allele G of SHMT1 rs638416 (OR = 2.80; 95%CI 1.51, 5.21; p = 0.013), allele T of Methylentetrahydrofolate Dehydrogenase (MTHFD) rs2236225 (OR = 3.09; 95%CI 1.27, 7.50; p = 0.016) and allele A of Methionine Synthase Reductase (MTRR) rs1801394 (OR = 2.35; 95CI 1.10, 5.00; p = 0.037). An inflammatory oxidative stress enzyme, Gluthatione S-Tranferase Mu-1(GSTM1), null allele (OR = 2.21; 95%CI 1.24, 4.36; p = 0.030) and a neurotransmission receptor, Dopamine Receptor D4 (DRD4), long allele of 48 bp-repeat (OR = 3.62; 95%CI 0.76, 17.26; p = 0.161). CONCLUSIONS Some genetic polymorphisms related to folates metabolism, inflammatory oxidative stress, and neurotransmission responses to pain, has been significantly associated to TMD syndrome.
Resumo:
The CTLA-4 protein is expressed in activated T cells and plays an essential role in the immune response through its regulatory effect on T cell activation. Polymorphisms of the CTLA-4 gene have been correlated with autoimmune, neoplastic and infectious illnesses. This work aimed to verify possible associations between single nucleotide polymorphisms (SNPs) in CTLA-4, -318C/T in the promoter and +49A/G in exon 1 and paracoccidioidomycosis (PCM) caused by Paracoccidioides brasiliensis. For this purpose, 66 chronic form PCM patients and 76 healthy controls had their allele, genotype and haplotype frequencies determined. The genetic admixture structure of the patients and controls was evaluated to eliminate ancestral bias. The comparison of frequencies indicated no significant differences between patients and controls that could link the SNPs to PCM. Groups were admixture matched with no difference observed in population ancestry inference, indicating that the absence of association between CTLA-4 polymorphisms and PCM could not be attributed to ancestral bias. This study showed that there was no association between the CTLA-4 SNPs -318 and +49 and the resistance or susceptibility to PCM.
Resumo:
MDL 100,240, a dual inhibitor of angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP), was administered intravenously to two panels of four healthy males in a four-period, dose-increasing (0, 1.56, 6.25, and 25 mg, and 0, 3.13, 12.5, and 50 mg, respectively) double-blind, placebo-controlled study. Plasma ACE activity and blood-pressure response to exogenous angiotensin I and angiotensin II i.v. challenges and safety and tolerance were assessed over a 24-h period. MDL 100,240 induced a rapid, dose-related, and sustained inhibition of ACE (>70% over 24 h at doses > or =12.5 mg). The time integral of ACE inhibition was related to the dose but with near-maximal values already attained at doses > or =12.5 mg. Systolic and diastolic blood-pressure responses to exogenous angiotensin I challenges were inhibited in a dose-dependent fashion, whereas the effects of angiotensin II remained unaffected. Mean supine blood pressure decreased transiently (3 h) at doses > or =3.125 mg and < or =24 h with the 25- and 50-mg doses, but not significantly. MDL 100,240 was well tolerated. In healthy subjects, MDL 100,240 exerts a dose-dependent and long-lasting ACE-blocking activity, also expressed by the inhibition of the pressor responses to exogenous angiotensin I challenges. The baroreceptor reflex, assessed by the response to exogenous angiotensin II challenge, remains unaltered.
Resumo:
Heteroduplex mobility assay, single-stranded conformation polymorphism and nucleotide sequencing were utilised to genotype human parvovirus B19 samples from Brazil and Paraguay. Ninety-seven serum samples were collected from individuals presenting with abortion or erythema infectiosum, arthropathies, severe anaemia and transient aplastic crisis; two additional skin samples were collected by biopsy. After the procedure, all clinical samples were classified as genotype 1.
Resumo:
The recognition of pathogen-derived structures by C-type lectins and the chemotactic activity mediated by the CCL2/CCR2 axis are critical steps in determining the host immune response to fungi. The present study was designed to investigate whether the presence of single nucleotide polymorphisms (SNPs) within DC-SIGN, Dectin-1, Dectin-2, CCL2 and CCR2 genes influence the risk of developing Invasive Pulmonary Aspergillosis (IPA). Twenty-seven SNPs were selected using a hybrid functional/tagging approach and genotyped in 182 haematological patients, fifty-seven of them diagnosed with proven or probable IPA according to the 2008 EORTC/MSG criteria. Association analysis revealed that carriers of the Dectin-1(rs3901533 T/T) and Dectin-1(rs7309123 G/G) genotypes and DC-SIGN(rs4804800 G), DC-SIGN(rs11465384 T), DC-SIGN(7248637 A) and DC-SIGN(7252229 C) alleles had a significantly increased risk of IPA infection (OR = 5.59 95%CI 1.37-22.77; OR = 4.91 95%CI 1.52-15.89; OR = 2.75 95%CI 1.27-5.95; OR = 2.70 95%CI 1.24-5.90; OR = 2.39 95%CI 1.09-5.22 and OR = 2.05 95%CI 1.00-4.22, respectively). There was also a significantly increased frequency of galactomannan positivity among patients carrying the Dectin-1(rs3901533_T) allele and Dectin-1(rs7309123_G/G) genotype. In addition, healthy individuals with this latter genotype showed a significantly decreased level of Dectin-1 mRNA expression compared to C-allele carriers, suggesting a role of the Dectin-1(rs7309123) polymorphism in determining the levels of Dectin-1 and, consequently, the level of susceptibility to IPA infection. SNP-SNP interaction (epistasis) analysis revealed significant interactions models including SNPs in Dectin-1, Dectin-2, CCL2 and CCR2 genes, with synergistic genetic effects. Although these results need to be further validated in larger cohorts, they suggest that Dectin-1, DC-SIGN, Dectin-2, CCL2 and CCR2 genetic variants influence the risk of IPA infection and might be useful in developing a risk-adapted prophylaxis.
Resumo:
BACKGROUND Data on which to base definitive recommendations on the doses and duration of therapy for genotype 3 HCV/HIV-coinfected patients are scarce. We evaluated the efficacy of a lower peginterferon-α 2a dose and a shorter duration of therapy than the current standard of care in genotype 3 HCV/HIV-coinfected patients. METHODS AND FINDINGS Pilot, open-label, single arm clinical trial which involved 58 Caucasian HCV/HIV-coinfected patients who received weekly 135 µg peginterferon-α 2a plus ribavirin 400 mg twice daily during 20 weeks after attaining undetectable viremia. The relationships between baseline patient-related variables, including IL28B genotype, plasma HCV-RNA, ribavirin dose/kg, peginterferon-α 2a and ribavirin levels with virological responses were analyzed. Only 4 patients showed lack of response and 5 patients dropped out due to adverse events related to the study medication. Overall, sustained virologic response (SVR) rates were 58.3% by intention-to-treat and 71.4% by per protocol analysis, respectively. Among patients with rapid virologic response (RVR), SVR and relapses rates were 92.6% and 7.4%, respectively. No relationships were observed between viral responses and ribavirin dose/kg, peginterferon-α 2a concentrations, ribavirin levels or rs129679860 genotype. CONCLUSIONS Weekly 135 µg pegIFN-α 2a could be as effective as the standard 180 µg dose, with a very low incidence of severe adverse events. A 24-week treatment duration appears to be appropriate in patients achieving RVR, but extending treatment up to just 20 weeks beyond negativization of viremia is associated with a high relapse rate in those patients not achieving RVR. There was no influence of IL28B genotype on the virological responses.
Resumo:
Reliable molecular markers are essential for a better understanding of the molecular epidemiology of Plasmodium vivax, which is a neglected human malaria parasite. The aim of this study was to analyze the genetic diversity of P. vivax isolates from the Brazilian Amazon using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the highly polymorphic merozoite surface protein-3alpha (PvMSP-3α) gene. To accomplish this, 60 isolates of P. vivax from different endemic areas in the Brazilian Amazon were collected. The PvMSP-3α gene was amplified by nested-PCR. Three major types of the PvMSP-3α locus were detected at different frequencies: type A (68%), B (15%) and C (17%). A single sample showed two PCR fragments, which corresponded to infection with types A and C. PCR-RFLP analysis using the HhaI restriction enzyme for 52 isolates clearly identified 11 haplotypes, eight of which were from type A, two from type B and only one from type C. Seven other isolates did not show a clear pattern using PCR-RFLP. This result might be due to multiple clone infections. This study showed a high diversity of the PvMSP-3α gene among P. vivax isolates from the Brazilian Amazon, but also indicated that the detection performance of PCR-RFLP of the PvMSP-3α gene may not be sufficient to detect multiple clone infections.
Resumo:
In human heart failure (HF) peroxisome proliferator-activated receptor alpha (PPAR alpha) is downregulated and consequently, the expression of genes involved in fatty acid oxidation repressed. The L162V (rs1800206) is a functional polymorphism of the human PPAR alpha gene (PPARA). In the present study we have investigated whether this polymorphism is associated with the development of stage C of HF.
Resumo:
RAPPORT DE SYNTHESE La dégénérescence maculaire liée à l'âge (DMLA) est une maladie très fréquente qui représente la cause principale de cécité légale chez les sujets de plus de 50 ans en Occident. Bien que l'étiologie exacte de cette affection ne soit pas complètement connue, des facteurs environnementaux et génétiques influencent sa survenue et son évolution. A ce sujet, de récentes recherches ont notamment montré une association marquée à une variante du gène CFH, Y402H. Nous ignorons toutefois si le polymorphisme Y402H est associé à un phénotype particulier de la maladie. Cette étude a pour but d'établir si cette variante du gène CFH est associée à certaines caractéristiques phénotypiques précoces. L'étude porte sur quatre cent vingt patients atteints de DMLA qui ont été phénotypés sur la base de photographie du fond d'oeil (International Classification and Grading system for age- related macular degeneration) et génotypés à partir d'ADN leucocytaire à la recherche de la variante Y402H du gène CFH. Ces données ont ensuite fait l'objet d'une analyse statistique de l'association génotype-phénotype (le génotype de 50 sujets-contrôle a été utilisé pour confirmer l'association du polymorphisme avec la DMLA). Les résultats obtenus, corrigés pour l'âge et le sexe, montrent un odds ratio (OR) de développer une DMLA de 2.95 en présence d'au moins un allèle à risque C et de 9.05 pour les homozygotes CC. Par contre, aucune influence n'est observée sur les stades de la maladie (précoce-tardif)? Une association significative entre le génotype CC et la présence de druses périphériques (p=0.028), ainsi que la localisation centrale des druses (p=0,049) a été mise en évidence. Aucune autre tendance n'a été dégagée concernant les critères restants (taille, surface totale recouverte, localisation nasale des druses) ou les changements pigmentaires. Cette étude a permis de confirmer l'association entre la variante Y4G2H et la DMLA dans la population suisse et de conclure que la variante Y402H du gène CFH présente une association géno-phénotypique pour certaines caractéristiques des druses. Il est probable que d'autres facteurs génétiques encore influencent le phénotype de la DMLA. De nouvelles recherches seront nécessaires pour préciser l'influence de ces autres facteurs génétiques ou environnementaux, en vue d'une meilleure compréhension de la pathogenèse de cette affection, et pour développer des mesures thérapeutiques et prophylactiques adaptées.
Resumo:
It is widely accepted that pharmacologic reduction of the blood pressure of hypertensive patients reduces the risk of at least some of the major cardiovascular complications (1-5). All major studies were carried out before orally active converting enzyme inhibitors had become available. In other words, very effective antihypertensive drugs have been around for quite some time and have already proven their efficacy. Therefore, the considerable enthusiasm that has developed during the very recent years for the new converting enzyme inhibitors should be evaluated in the light of previously available antihypertensive drugs, the more so, as drugs cheaper than converting enzyme inhibiting agents are presently available. Thus, the increased expense when using this new class of antihypertensive compounds should be justified by a therapeutic gain. When evaluating a class of antihypertensive drugs such as converting enzyme inhibitors, there are basically three main considerations: What is their efficacy in long-term use? This includes the effect on blood pressure, on heart, on hemodynamics, and on blood flow distribution. What are the metabolic effects? What is the effect on sodium and potassium excretion? How are the serum lipids affected by its use? Are there any untoward effects related either to the chemical structure of the compound per se or rather to the approach? In particular, are there any central effects of the drug which can cause discomfort to the patient? The following discussion has the principal aim to review these aspects with chronic use of oral converting enzyme inhibiting agents without, however, even attempting to provide an exhaustive review of the subject.