867 resultados para Practice as an Curricular Component
Resumo:
Cellulose nanofibers are an attractive component of a broad range of nanomaterials. Their intriguing mechanical properties and low cost, as well as the renewable nature of cellulose make them an appealing alternative to carbon nanotubes (CNTs), which may pose a considerable health risk when inhaled. Little is known, however, concerning the potential toxicity of aerosolized cellulose nanofibers. Using a 3D in vitro triple cell coculture model of the human epithelial airway barrier, it was observed that cellulose nanofibers isolated from cotton (CCN) elicited a significantly (p < 0.05) lower cytotoxicity and (pro-)inflammatory response than multiwalled CNTs (MWCNTs) and crocidolite asbestos fibers (CAFs). Electron tomography analysis also revealed that the intracellular localization of CCNs is different from that of both MWCNTs and CAFs, indicating fundamental differences between each different nanofibre type in their interaction with the human lung cell coculture. Thus, the data shown in the present study highlights that not only the length and stiffness determine the potential detrimental (biological) effects of any nanofiber, but that the material used can significantly affect nanofiber-cell interactions.
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In this study, we evaluated the potential use of entomopathogenic nematodes as a control for the beetle Aethina tumida Murray (Coleoptera: Nitidulidae). In particular, we conducted 1) four screening bioassays to determine nematode (seven species, 10 total strains tested) and application level effects on A. tumida larvae and pupae, 2) a generational persistence bioassay to determine whether single inoculations with nematodes would control multiple generations of A. tumida larvae in treated soil, and 3) a field bioassay to determine whether the nematodes would remain efficacious in the field. In the screening bioassays, nematode efficacy varied significantly by tested nematode and the infective juvenile (IJ) level at which they were applied. Although nematode virulence was moderate in screening bioassays 1-3 (0 - 68% A. tumida mortality), A. tumida mortality approached higher levels in screening bioassay 4 (nearly 100% after 39 d) that suggest suitable applicability of some of the test nematodes as field controls for A. tumida. In the generational persistence bioassay, Steinernema Hobrave Cabanillas, Poinar & Raulston 7-12 strain and Heterorhabditis indica Poinar, Karunaka & David provided adequate A. tumida control for 19 wk after a single soil inoculation (76-94% mortality in A. tumida pupae). In the field bioassay, the same two nematode species also showed high virulence toward pupating A. tumida (88-100%) mortality. Our data suggest that nematode use may be an integral component of an integrated pest management scheme aimed at reducing A. tumida populations in bee colonies to tolerable levels.
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Protein is an essential component for life, and its synthesis is mediated by codons in any organisms on earth. While some codons encode the same amino acid, their usage is often highly biased. There are many factors that can cause the bias, but a potential effect of mononucleotide repeats, which are known to be highly mutable, on codon usage and codon pair preference is largely unknown. In this study we performed a genomic survey on the relationship between mononucleotide repeats and codon pair bias in 53 bacteria, 68 archaea, and 13 eukaryotes. By distinguishing the codon pair bias from the codon usage bias, four general patterns were revealed: strong avoidance of five or six mononucleotide repeats in codon pairs; lower observed/expected (o/e) ratio for codon pairs with C or G repeats (C/G pairs) than that with A or T repeats (A/T pairs); a negative correlation between genomic GC contents and the o/e ratios, particularly for C/G pairs; and avoidance of C/G pairs in highly conserved genes. These results support natural selection against long mononucleotide repeats, which could induce frameshift mutations in coding sequences. The fact that these patterns are found in all kingdoms of life suggests that this is a general phenomenon in living organisms. Thus, long mononucleotide repeats may play an important role in base composition and genetic stability of a gene and gene functions.
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Airway management for successful ventilation by laypersons and inexperienced healthcare providers is difficult to achieve. Bag-valve mask (BVM) ventilation requires extensive training and is performed poorly. Supraglottic airway devices (SADs) have been successfully introduced to clinical resuscitation practice as an alternative. We evaluated recently introduced (i-gel™ and LMA-Supreme™) and established SADs (LMA-Unique™, LMA-ProSeal™) and BVM used by laypeople in training sessions on manikins.
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Femoroacetabular impingement is a well-described pre-arthritic condition with two main types; cam and pincer. Studies using the open treatment for impingement have described patterns of articular cartilage wear specific to cam and pincer impingement. Assessing articular damage in the hip joint is an important component of treatment. Intravenous gadolidium allows radiologists to perform an indirect assessment of articular cartilage glycosaminoglycan (GAG) content by using a technique called dGEMRIC. Using this indirect assessment of articular cartilage, we compared the dGEMRIC indices in a group of six cam and seven pincer patients to a control group (n = 12) of asymptomatic controls that had no plain MRI findings of osteoarthritis. The superior portion of the hip joint was divided into seven regions from 9 to 3 o'clock. These regions were then subdivided into peripheral and central regions. The cam and pincer groups both had statistically lower dGEMRIC values compared to the control group. The cam group demonstrated not only peripheral but also central involvement of the joint and this was concentrated in the anterior portion of the joint. The pincer group exhibited more global hip involvement with all areas of the hip averaging a dGEMRIC index 28% less than controls. With the use of dGEMRIC more specific patterns of cartilage wear can be elicited in patients with impingement, which may improve patient selection and help better understand the progression of osteoarthithis throughout the hip joint.
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Objectives To compare the use of pair-wise meta-analysis methods to multiple treatment comparison (MTC) methods for evidence-based health-care evaluation to estimate the effectiveness and cost-effectiveness of alternative health-care interventions based on the available evidence. Methods Pair-wise meta-analysis and more complex evidence syntheses, incorporating an MTC component, are applied to three examples: 1) clinical effectiveness of interventions for preventing strokes in people with atrial fibrillation; 2) clinical and cost-effectiveness of using drug-eluting stents in percutaneous coronary intervention in patients with coronary artery disease; and 3) clinical and cost-effectiveness of using neuraminidase inhibitors in the treatment of influenza. We compare the two synthesis approaches with respect to the assumptions made, empirical estimates produced, and conclusions drawn. Results The difference between point estimates of effectiveness produced by the pair-wise and MTC approaches was generally unpredictable—sometimes agreeing closely whereas in other instances differing considerably. In all three examples, the MTC approach allowed the inclusion of randomized controlled trial evidence ignored in the pair-wise meta-analysis approach. This generally increased the precision of the effectiveness estimates from the MTC model. Conclusions The MTC approach to synthesis allows the evidence base on clinical effectiveness to be treated as a coherent whole, include more data, and sometimes relax the assumptions made in the pair-wise approaches. However, MTC models are necessarily more complex than those developed for pair-wise meta-analysis and thus could be seen as less transparent. Therefore, it is important that model details and the assumptions made are carefully reported alongside the results.
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Diagnostics imaging is an essential component of patient selection and treatment planning in oral rehabilitation by means of osseointegrated implants. In 2002, the EAO produced and published guidelines on the use of diagnostic imaging in implant dentistry. Since that time, there have been significant developments in both the application of cone beam computed tomography as well as in the range of surgical and prosthetic applications that can potentially benefit from its use. However, medical exposure to ionizing radiation must always be justified and result in a net benefit to the patient. The as low a dose as is reasonably achievable principle must also be applied taking into account any alternative techniques that might achieve the same objectives. This paper reports on current EAO recommendations arising from a consensus meeting held at the Medical University of Warsaw (2011) to update these guidelines. Radiological considerations are detailed, including justification and optimization, with a special emphasis on the obligations that arise for those who prescribe or undertake such investigations. The paper pays special attention to clinical indications and radiographic diagnostic considerations as well as to future developments and trends.
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The glycine deportation system is an essential component of glycine catabolism in man whereby 400 to 800mg glycine per day are deported into urine as hippuric acid. The molecular escort for this deportation is benzoic acid, which derives from the diet and from gut microbiota metabolism of dietary precursors. Three components of this system, involving hepatic and renal metabolism, and renal active tubular secretion help regulate systemic and central nervous system levels of glycine. When glycine levels are pathologically high, as in congenital nonketotic hyperglycinemia, the glycine deportation system can be upregulated with pharmacological doses of benzoic acid to assist in normalization of glycine homeostasis. In congenital urea cycle enzymopathies, similar activation of the glycine deportation system with benzoic acid is useful for the excretion of excess nitrogen in the form of glycine. Drugs which can substitute for benzoic acid as substrates for the glycine deportation system have adverse reactions that may involve perturbations of glycine homeostasis. The cancer chemotherapeutic agent ifosfamide has an unacceptably high incidence of encephalopathy. This would appear to arise as a result of the production of toxic aldehyde metabolites which deplete ATP production and sequester NADH in the mitochondrial matrix, thereby inhibiting the glycine deportation system and causing de novo glycine synthesis by the glycine cleavage system. We hypothesize that this would result in hyperglycinemia and encephalopathy. This understanding may lead to novel prophylactic strategies for ifosfamide encephalopathy. Thus, the glycine deportation system plays multiple key roles in physiological and neurotoxicological processes involving glycine.
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Therapeutic Drug Utilization Review (DUR) is an important component of state-level pharmaceutical assistance programs.
A prospective study of the impact of air pollution on respiratory symptoms and infections in infants
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Rationale: There is increasing evidence that short-term exposure to air pollution has a detrimental effect on respiratory health, but data from healthy populations, particularly infants, are scarce. Objectives: To assess the association of air pollution with frequency and severity of respiratory symptoms and infections measured weekly in healthy infants. Methods: In a prospective birth cohort of 366 infants of unselected mothers, respiratory health was assessed weekly by telephone interviews during the first year of life (19,106 total observations). Daily mean levels of particulate matter (PM10), nitrogen dioxide (NO2), and ozone (O3) were obtained from local monitoring stations. We determined the association of the preceding week's pollutant levels with symptom scores and respiratory tract infections using a generalized additive mixed model with an autoregressive component. In addition, we assessed whether neonatal lung function influences this association and whether duration of infectious episodes differed between weeks with normal PM10 and weeks with elevated levels. Measurements and Main Results: We found a significant association between air pollution and respiratory symptoms, particularly in the week after respiratory tract infections (risk ratio, 1.13 [1.02-1.24] per 10 μg/m(3) PM10 levels) and in infants with premorbid lung function. During times of elevated PM10 (>33.3 μg/m(3)), duration of respiratory tract infections increased by 20% (95% confidence interval, 2-42%). Conclusions: Exposure to even moderate levels of air pollution was associated with increased respiratory symptoms in healthy infants. Particularly in infants with premorbid lung function and inflammation, air pollution contributed to longer duration of infectious episodes with a potentially large socioeconomic impact.
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This project was an experiment in widening the traditional borders of study in the field and looking at the phenomenon of Gothic taste in many genres and kinds of art. The Gothic taste was a major element in the cultural image of the Enlightenment both in western Europe and in Russia. It was an essential component in the world outlook of an educated person and without studying this phenomenon it is impossible to fully understand the thinking of artistic professionals, amateurs and users in Russian society in the 18th century. Mr. Khatchatourov first analysed the reasons for the importance of Gothic taste in the culture of the European Enlightenment and then studied its linguistic and lexicographic evolution in 18th century Russian culture. He sought to determine the semantic context which actively formed the human mind set in the Enlightenment, including potential users and producers of articles in the Gothic taste. He then looked at the process of absorption of this concept by those forms of art which express it most strongly, in particular architecture and the theatre. His study was based on a comprehensive historical and culturological study using a wide range of sources, a formal stylistic method approach considering the interaction of non-classical styles of the Enlightenment with the dominant classicism, and an iconographic approach which revealed the essential aspects in a new image synthesis of the culture of the Enlightenment.
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PURPOSE: This study was conducted to elucidate the impact of loss of heterozygosity (LOH) for chromosomes 1p36 and 19q13 on the overall survival of patients with diffusely infiltrating WHO grade 2 gliomas treated without chemotherapy. PATIENTS AND METHODS: We assessed the LOH status of tumors from patients harboring WHO grade 2 gliomas diagnosed between 1991 and 2000. Patients were either followed after initial biopsy or treated by surgery and/or radiation therapy (RT). Overall survival, time to malignant transformation, and progression-free survival were last updated as of March 2005. RESULTS: Of a total of 79 patients, LOH 1p36 and LOH 19q13 could be assessed in 67 and 66 patients, respectively. The median follow-up after diagnosis was 6 years. Loss of either 1p or 19q, in particular codeletion(s) at both loci, was found to positively impact on both overall survival (log-rank P < .01), progression-free survival, and survival without malignant transformation (P < .05). Tumor volume (P < .0001), neurologic deficits at diagnosis (P < .01), involvement of more than one lobe (P < .01), and absence of an oligodendroglial component (P < .05) were also predictors of shorter overall survival. The extent of surgery was similar in patients with or without LOH 1p and/or 19q; RT was more frequently resorted to for patients without than for patients with LOH 1p/19q (30% v 60%). CONCLUSION: The presence of LOH on either 1p36 or 19q13, and in particular codeletion of both loci is a strong, nontreatment-related, prognostic factor for overall survival in patients with diffusely infiltrating WHO grade 2 gliomas.
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BACKGROUND: Fever in neutropenia (FN) is a frequent complication in pediatric oncology. Deficiency of mannose-binding lectin (MBL), an important component of innate immunity, is common due to genetic polymorphisms, but its impact on infections in oncologic patients is controversial. This study investigated whether MBL serum levels at cancer diagnosis are associated with the development of FN in pediatric cancer patients. PROCEDURE: Serum MBL was measured using ELISA. Frequency, duration, and cause of FN were assessed retrospectively. Association with MBL level was analyzed using uni- and multivariate Poisson regression taking into account both intensity and duration of chemotherapy. RESULTS: In 94 children, with a cumulative follow-up time of 81.7 years, 177 FN episodes were recorded. Patients with both very low MBL levels (<100 microg/L; risk ratio (RR), 1.93; 95% CI, 1.14-3.28; P = 0.014) and normal MBL levels (>/=1,000 microg/L; RR, P = 0.011) had significantly more frequent FN episodes than patients with low MBL levels (100-999 microg/L). Patients with very low MBL levels had significantly more episodes of FN with severe bacterial infection (bacteremia or pneumonia; RR, 4.49; 1.69 = 11.8; P = 0.003), while those with normal MBL levels had more FN episodes with no microbial etiology identified (RR, 1.85; 1.14 = 3.03; P = 0.014). CONCLUSIONS: Very low MBL levels are associated with more frequent FN episodes, mainly due to severe bacterial infections. The surprising finding that children with normal MBL levels had more frequent FN episodes than those with low MBL levels needs testing in prospective studies. Pediatr Blood Cancer (c) 2006 Wiley-Liss, Inc.
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Despite a growing awareness that the herbaceous layer serves a special role in maintaining the structure and function of forests, this stratum remainsan underappreciated aspect of forest ecosystems. In this article I review and synthesize information concerning the herb layer’s structure,composition, and dynamics to emphasize its role as an integral component of forest ecosystems. Because species diversity is highest in the herb layeramong all forest strata, forest biodiversity is largely a function of the herb-layer community. Competitive interactions within the herb layer candetermine the initial success of plants occupying higher strata, including the regeneration of dominant overstory tree species. Furthermore, the herblayer and the overstory can become linked through parallel responses to similar environmental gradients. These relationships between strata varyboth spatially and temporally. Because the herb layer responds sensitively to disturbance across broad spatial and temporal scales, its dynamics canprovide important information regarding the site characteristics of forests, including patterns of past land-use practices. Thus, the herb layer has asignificance that belies its diminutive stature.
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Activated platelets bind numerous adhesive and procoagulant proteins by receptor-mediated processes. Although there is little evidence to suggest that these processes are heterogeneous in platelets, we previously found that platelets co-stimulated with collagen and thrombin express functional alpha-granule factor V only on a subpopulation of cells. Here we show that these cells, referred to as 'COAT-platelets', bind additional alpha-granule proteins, including fibrinogen, von Willebrand factor, thrombospondin, fibronectin and alpha2-antiplasmin. These proteins are all transglutaminase substrates, and inhibitors of transglutaminase prevent the production of COAT-platelets. A synthetic transglutaminase substrate (CP15) also binds to COAT-platelets, and analysis by high performance liquid chromatography/mass spectrometry shows that a product is formed with a relative molecular mass (Mr) equal to CP15 plus 176. Serotonin, an abundant component of platelet-dense granules, has an Mr of 176, and fibrinogen isolated from COAT-platelets contains covalently linked serotonin. Synthetic bovine serum albumin-(serotonin)6 binds selectively to COAT-platelets and also inhibits the retention of procoagulant proteins on COAT-platelets. These data indicate that COAT-platelets use serotonin conjugation to augment the retention of procoagulant proteins on their cell surface through an as yet unidentified serotonin receptor.