842 resultados para systematic toxicological analysis


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The model of development and evolution of complex morphological structures conceived by Atchley and Hall in 1991 (Biol. Rev. 66:101-157), which establishes that changes at the macroscopic, morphogenetic level can be statistically detected as variation in skeletal units at distinct scales, was applied in combination with the formalism of geometric morphometrics to study variation in mandible shape among populations of the rodent species Thrichomys apereoides. The thin-plate spline technique produced geometric descriptors of shape derived from anatomical landmarks in the mandible, which we used with graphical and inferential approaches to partition the contribution of global and localized components to the observed differentiation in mandible shape. A major pattern of morphological differentiation in T. apereoides is attributable to localized components of shape at smaller geometric scales associated with specific morphogenetic units of the mandible. On the other hand, a clinal trend of variation is associated primarily with localized components of shape at larger geometric scales. Morphogenetic mechanisms assumed to be operating to produce the observed differentiation in the specific units of the mandible include mesenchymal condensation differentiation, muscle hypertrophy, and tooth growth. Perspectives for the application of models of morphological evolution and geometric morphometrics to morphologically based systematic biology are considered.

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The aim of this meta-analysis was to compare the efficacy of gonadotrophin antagonist (GnRH-ant) versus GnRH agonist (GnRHa) as coadjuvant therapy for ovarian stimulation in poor ovarian responders in IVF/intracytoplasmic sperm injection cycles. Search strategies included on-line surveys of databases such as MEDLINE, EMBASE and others. A fixed effects model was used for odds ratio (OR) and effect size (weighted mean difference, WMD). Six trials fulfilled the inclusion criteria (randomized controlled trials). There was no difference between GnRH-ant and GnRHa (long and flare-up protocols) with respect to cycle cancellation rate, number of mature oocytes and clinical pregnancy rate per cycle initiated, per oocyte retrieval and per embryo transfer. When the mete-analysis was applied to the two trials that had used GnRH-ant versus long protocols of GnRHa, a significantly higher number of retrieved oocytes was observed in the GnRH-ant protocols [P = 0.018; WMD: 1.12 (0.18, 2.05)]. However, when the meta-analysis was applied to the four trials that had used GnRH-ant versus flare-up protocols, a significantly higher number of retrieved oocytes (P = 0.032; WMD: -0.51, 95% CI -0.99, -0.04) was observed in the GnRHa protocols. Nevertheless, additional randomized controlled trials with better planning are needed to confirm these results.

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This study aims to compare the efficacy of recombinant LH (rLH) supplementation for ovarian stimulation in gonadotrophin-releasing hormone-antagonist protocol for IVF/intracytoplasmic sperm injection cycles. Search strategies included online surveys of databases. The fixed effects model was used for odds ratio (OR) and effect size (weighted mean difference, WMD). Five trials fulfilled the inclusion criteria. When the meta-analysis was carried out, advantages were observed for the LH supplementation protocol with respect to higher serum oestradiol concentrations on the day of human chorionic gonadotrophin administration (P < 0.0001; WMD: 514, 95% CI 368, 660) and higher number of mature oocytes (P = 0.0098; WMD: 0.88, 95% CI 0.21, 1.54). However, these differences were not observed in the total amount of recombinant FSH (rFSH) administered, days of stimulation, number of oocytes retrieved, the clinical pregnancy rate per oocyte retrieval, the implantation rate and miscarriage rate. This result demonstrates that the association of rLH with rFSH may prevent any decrease in oestradiol after antagonist administration and that a significantly higher number of mature oocytes was available for laboratory work. Nevertheless, it failed to show any statistically significant difference in clinically significant end-points in IVF (implantation and pregnancy rates). Additional randomized controlled trials are needed to confirm these results further. © 2007 Published by Reproductive Healthcare Ltd.

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Preterm birth is a major problem in public health in developed and developing countries and the search for risk factors of this event is important. The aim of this study was to review the effect of periodontal treatment on the incidence of preterm delivery. A wide research was executed considering an evaluation period between November of 1998 and October of 2009 at MEDLINE/PUBMED databases. The selection strategy consisted of the search for the following key-words: periodontal therapy or periodontal disease and pregnancy outcome or preterm birth. The search was limited for articles written in English. The randomized clinical trials that evaluated the effect of the non-surgical periodontal treatment on the incidence of Preterm Low Birth Weight (PLBW) were selected. In a total of 7 papers selected, the incidence of PLBW was lower in groups of women who were submitted to periodontal treatment. Reductions of Preterm Birth (PTB) ranged from 0.8% to 28.01%, while reduction of Low Birth Weight (LBW) ranged from 0.44% to 33%. In studies that analyzed these two variables together, there was variation between 4.57% to 71.5% in rates reduction. Due to heterogeneity of the data, the meta-analysis was not applied. The majority of the studies concluded that non-surgical periodontal treatment in pregnant women reduces incidence of preterm babies with low weight.

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Background: Paradoxical cases of psoriatic lesions induced or exacerbated by anti-tumor necrosis factor (TNF)-α therapy have been reported more frequently in recent years, but data related to inflammatory bowel disease (IBD) are rare. A systematic literature review was performed to provide information about this adverse effect in patients with IBD who receive anti-TNF therapy. Methods: Published studies were identified by a search of Medline, Embase, Cochrane, SciELO, and LILACS databases. Results: A total of 47 studies (222 patients) fulfilled the inclusion criteria and were selected for analysis. Clinical and therapeutic aspects varied considerably among these reports. Of the 222 patients, 78.38% were diagnosed with Crohn's disease, and 48.20% were female. The mean patient age was 26.50. years, and 70.72% of patients had no history of psoriasis. Patients developed psoriasiform lesions (55.86%) more often than other types of psoriatic lesions, and infliximab was the anti-TNF-α therapy that caused the cutaneous reaction in most patients (69.37%). Complete remission of cutaneous lesions was observed in 63.96% of the cases. Conclusions: We found that psoriatic lesions occurred predominantly in adult patients with Crohn's disease who received infliximab and had no previous history of psoriasis. Most patients can be managed conservatively without discontinuing anti-TNF-α therapy. © 2012 European Crohn's and Colitis Organisation.

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The specific identification and systematic of triatomines have been based fundamentally on morphological observations. These organisms are classified into complexes and specific subcomplexes, principally for morphological parameters and geographical disposition. The use of cytogenetic analyzes has been represented as a tool in systematic and taxonomy of triatomines. Thus, the present work, through the analysis of spermiogenesis, aims to characterize this stage of spermatogenesis in triatomines little studied, and especially to compare it among the species Triatoma lenti and T. sherlocki, to assist in the diagnosis of differentiation of these insects. The presence of the heteropyknotic corpuscle is shown as a diagnostic tool to differentiate T. sherlocki and T. lenti, since it is absent in T. lenti. The analysis of the spermiogenesis in T. sherlocki also allowed us to address morphological differences between elongating cells, which were relatively smaller and more filamentous when compared to T lenti. Furthermore, the flagellum was observed in all stages of cell differentiation and elongation. This structure, which helps in the locomotion of the sperm, is hardly observed in cytogenetic analysis, especially throughout spermiogenesis. Thus, although other comparative approaches should be taken, this paper allowed emphasizing the analysis of spermiogenesis as an important cytotaxonomic tool that assists in the differentiation of morphologically related species, such as T. lenti and T. sherlocki. © 2013 Académie des sciences.

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The leaf-cut ants are important agricultural pest, because they can cause intense defoliation in plants and destroy large areas cultivated. Although there are several works for the control of these insects by examining the toxicity of natural chemical compounds on various species of ants, few are focused on analyses of morphological changes caused in the affected organs. The aim of this study was to evaluate the effects of hydramethylnon on Atta sexdens rubropilosa workers through toxicological bioassays and morphological analysis of the post-pharyngeal glands, midgut, and Malpighian tubules of these ants. Hydramethylnon dissolved either in acetone (HA) or in a mixture of acetone and soy oil (HAO) was added to the artificial diet at a concentration of 200 μg/mL. The workers fed daily with the diet containing hydramethylnon showed higher mortality than the controls, especially when HAO was used. Moreover, light and electron microscopy revealed morphological alterations in the midgut and Malpighian tubules of workers treated with HA, whereas alterations of the post-pharyngeal glands were observed in the HAO-treated group. These results indicated that the presence of soy oil provided an alternate route for the ingestion of the formicide's active ingredient and corroborated previous studies that suggested a role for the post-pharyngeal glands in lipid metabolism. Our findings suggest that the oil may carry hydramethylnon to the gland lumen, resulting in lower quantity of the active ingredient in the intestinal lumen and Malpighian tubules that explains the lower degree of morphological alterations in these structures in the workers treated with HAO. These results may provide insight into the toxicological effects of hydramethylnon on leaf-cutting ants and the use of vegetable oil as an adjuvant in baits to control ants. © 2012 Elsevier Ltd.

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Background: In the past 10 years, new anticoagulants (NACs) have been studied for venous thromboembolism (VTE) prophylaxis. Objective: To evaluate the risk/benefit profile of NACs versus enoxaparin for VTE prophylaxis in major orthopedic surgery. Methods: A systematic review of double-blind randomized phase III studies was performed. The search strategy was run from 2000 to 2011 in the main medical electronic databases in any language. Independent extraction of articles was performed by 2 authors using predefined data fields, including study quality indicators. Results: Fifteen published clinical trials evaluating fondaparinux, rivaroxaban, dabigatran, and apixaban were included. Primary efficacy (any deep vein thrombosis [DVT], nonfatal pulmonary embolism, or all-cause mortality) favored fondaparinux (relative risk [RR] 0.50; 95% CI, 0.39, 0.63) and rivaroxaban (RR, 0.50; 95% CI, 0.34, 0.73) over enoxaparin, although significant heterogeneity was observed in both series. The primary efficacy of dabigatran at 220 mg, apixaban, and bemiparin were similar, with RRs of 1.02 (95% CI, 0.86, 1.20), 0.63 (95% CI, 0.39, 1.01), and 0.87 (95% CI, 0.65, 1.17), respectively. The primary efficacy of dabigatran at 150 mg (RR, 1.20; 95% CI, 1.03, 1.41), was inferior to enoxaparin. The incidence of proximal DVT favored apixaban (RR, 0.45; 95% CI, 0.27, 0.75) only. Rivaroxaban (RR, 0.45; 95% CI, 0.27, 0,77) and apixaban (RR, 0.38; 95% CI, 0.16, 0.90) produced significantly lower frequencies of symptomatic DVT. The incidence of major VTE favored rivaroxaban (RR, 0.44; 95% CI, 0.25, 0.81), only. Bleeding risk was similar for all NACs, except fondaparinux (RR, 1.27; 95% CI, 1.04, 1.55), which exhibited a significantly higher any-bleeding risk compared with enoxaparin, and apixaban (RR, 0.88; 95% CI, 0.79, 0.99), which was associated with a reduced risk of any bleeding. Alanine amino transferase was significantly lower with 220 mg of dabigatran, (RR, 0.67; 95% CI, 0.79, 0.99) than with enoxaparin. Conclusions: NACs can be considered alternatives to conventional thromboprophylaxis regimens in patients undergoing elective major orthopedic surgery, depending on clinical characteristics and cost-effectiveness. The knowledge of some differences concerning efficacy or safety profile, pointed out in this systematic review, along with the respective limitations, may be useful in clinical practice. © 2013 Elsevier Inc. All rights reserved.

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Introduction: The goal of implant treatment is the formation of a direct bone-implant interface contact. Purpose: This study aimed to evaluate the possibilities of immediate loading treatment for edentulous patients rehabilitated with mandibular and maxillary overdentures. Material and methods: A literature review using the PubMed and BIREME databases between the periods of 1977 and 2011 was performed. Results: From an initial yield of 218 titles, 78 articles were selected for text analysis, finally resulting in 23 studies (16 prospective, 6 prospective randomized, and 1 prospective multicenter) that met the inclusion criteria. Conclusion: The immediate loading protocol through which the implants are subjected to occlusal function immediately after their placement was introduced to overcome this limitation. © 2013 Springer-Verlag Berlin Heidelberg.

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PURPOSE: This systematic review aimed to assess changes on spatiotemporal gait parameters due to fatigue. MATERIAL AND METHOD: A search was carried out in literature published from 1950 to December 2010 and retrieved 771 articles using terms referring to walking and fatigue in the title, abstract or keywords. Two researchers assessed the selection and quality of each article independently. RESULTS: Seven studies were selected for this systematic review, two of which reported on the same data set. Several spatiotemporal parameters were reported to change with fatigue, but the few variables studied in multiple studies, gait speed and stride or step length and stride time, were affected only in single studies. Fatigue appears to modulate spatiotemporal gait parameters, but the effects of fatigue appear to be dependent on the muscles that were fatigued, and age that appears to be a moderator of the effects of fatigue on gait. © 2013 - IOS Press and the authors. All rights reserved.

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Rationale and aim The aims of the Cochrane systematic reviews are to make readily available and up-to-date information for clinical practice, offering consistent evidence and straightforward recommendations. In 2004, we evaluated the conclusions from Cochrane systematic reviews of randomized controlled trials in terms of their recommendations for clinical practice and found that 47.83% of them had insufficient evidence for use in clinical practice. We proposed to reanalyze the reviews to evaluate whether this percentage had significantly decreased. Methods A cross-sectional study of systematic reviews published in the Cochrane Library (Issue 7, 2011) was conducted. We randomly selected reviews across all 52 Cochrane Collaborative Review Groups. Results We analyzed 1128 completed systematic reviews. Of these, 45.30% concluded that the interventions studied were likely to be beneficial, of which only 2.04% recommended no further research. In total, 45.04% of the reviews reported that the evidence did not support either benefit or harm, of which 0.8% did not recommend further studies and 44.24% recommended additional studies; the latter has decreased from our previous study with a difference of 3.59%. Conclusion Only a small number of the Cochrane collaboration's systematic reviews support clinical interventions with no need for additional research. A larger number of high-quality randomized clinical trials are necessary to change the 'insufficient evidence' scenario for clinical practice illustrated by the Cochrane database. It is recommended that we should produce higher-quality primary studies in active collaboration and consultation with global scholars and societies so that this can represent a major component of methodological advance in this context. © 2012 John Wiley & Sons Ltd.

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Many Caribbean youth are doing reasonably well. They live in loving and caring families, attend school and are involved in various social activities in their communities. The health and well-being of the children and youth1 in the Caribbean is, and has been, the centre of attention of many studies, meetings and policy directives set at the regional, subregional and national levels. Programmes have been put in place to address the basic needs of young children in the areas of health and education and to provide guidance and directives to youth and adolescents in the area of professional formation and transition to adulthood. Critical issues such as reproductive health and family planning combined with access to education and information on these topics have been promoted to some extent. And finally, the Caribbean is known for rather high school enrolment rates in primary education that hardly show any gender disparities. While the situation is still good for some, growing numbers of children and youth cannot cope anymore with the challenges experienced quite early in their lives. Absent parents, instable care-taking arrangements, violence and aggression subjected to at home, in schools and among their friends, lack of a perspective in schools and the labour-market, early sexual initiation and teenage pregnancies are some of those issues faced by a rising number of young persons in this part of the world. Emotional instability, psychological stress and increased violence are one of the key triggers for increased violence and involvement in crime exhibited by ever younger youth and children. Further, the region is grappling with rising drop-out rates in secondary education, declining quality schooling in the classrooms and increasing numbers of students who leave school without formal certification. Youth unemployment in the formal labour market is high and improving the quality of professional formation along with the provision of adequate employment opportunities would be critical to enable youth to complete consistently and effectively the transition into adulthood and to take advantage of the opportunities to develop and use their human capital in the process. On a rather general note, the region does not suffer from a shortage of policies and programmes to address the very specific needs of children and youth, but the prominent and severe lack of systematic analysis and monitoring of the situation of children, youth and young families in the Caribbean does not allow for targeted and efficient interventions that promise successful outcomes on the long term. In an effort to assist interested governments to fill this analytical gap, various initiatives are underway to enhance data collection and their systematic analysis2. Population and household censuses are conducted every decade and a variety of household surveys, such as surveys of living conditions, labour force surveys and special surveys focusing on particular sub-groups of the population are conducted, dependent on the resources available, to a varying degree in the countries of the region. One such example is the United Nations Children’s Fund (UNICEF)-funded Multi-Indicator Cluster Surveys (MICS) that assess the situation of children and youth in a country. Over the past years and at present, UNICEF has launched a series of surveys in a number of countries in the Caribbean3. But more needs to be done to ensure that the data available is analyzed to provide the empirical background information for evidence-based policy formulation and monitoring of the efficiency and effectiveness of the efforts undertaken.

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By means of a meta-analysis, this article sets out to estimate average values for the income and price elasticities of gasoline demand and to analyse the reasons for the variations in the elasticities reported by the literature. The findings show that there is publication bias, that the volatility of elasticity estimates is not due to sampling errors alone, and that there are systematic factors explaining these differences. The income and price elasticities of gasoline demand differ between the short and long run and by region, and the estimation can appropriately include the vehicle fleet and the prices of substitute goods, the data types and the estimation methods used. The presence of a low price elasticity suggests that a fuel tax will be inadequate to control rising consumption in a context of rapid economic growth.

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PURPOSE: Systematic reviews are criticized for frequently offering inconsistent evidences and absence of straightforward recommendations. Their value seems to be depreciated when the conclusions are uncertain. To describe an alternative approach of evaluating case series studies in health care when there is absence of clinical trials. METHODS: We provide illustrations from recent experiences. Proportional meta-analysis was performed on surgical outcomes: (a) case series studies, (b) use of cryoablation or radiofrequency ablation, and (c) patients with small renal cell carcinoma. The statistically significant difference between both interventions studied was defined if their combined 95% confidential interval (CI) did not overlap. RESULTS: As demonstrated by the example, this analysis is an alternative approach to provide some evidence of the intervention´s effects under evaluation and plotting all available case series in the absence of clinical trials for the health field. CONCLUSIONS: Although we are leading to a low level of evidence to determine efficacy, effectiveness and safety of interventions this alternative approach can help surgeons, physicians and health professionals for a provisionally decision in health care along with their clinical expertise and the patient´s wishes and circumstances in the absence of high-quality primary studies. It´s not a replacement for the gold standard randomized clinical trial, but an alternative analysis for clinical research.