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排序方式: 共有1693条查询结果,搜索用时 15 毫秒
141.
142.
Joana Cristina Medeiros Tavares Deborah Afonso Cornélio Naisandra Bezerra da Silva Carlos Eduardo Bezerra de Moura Jana Dara Freires de Queiroz Juliana Carvalho Sá Clodomiro Alves Junior Silvia Regina Batistuzzo de Medeiros 《Toxicology》2009
Titanium (Ti) is currently the most widely used material for the manufacture of orthopedic and dental implants. Changes in the surface of commercial pure Ti (cp Ti) can determine the functional response of cells, and is therefore a critical factor for the success of the implant. However, the genotoxicity of titanium surfaces has been poorly studied. Thus, the purpose of this study was to evaluate the genotoxic potential of a new titanium surface developed by plasma treatment using argon-ion bombardment and compare it with an untreated titanium surface. Accordingly, comet assay, analysis of chromosomal aberrations (CAs), and Cytokinesis Block Micronucleus (CBMN) assay were carried out, using CHO-K1 (Chinese hamster ovary) cells grown on both titanium surfaces. Our results show that the untreated titanium surface caused a significant increase in % tail moment, in the number of cells with CAs, tetraploidy, micronucleus frequency, and other nuclear alterations when compared with the negative control and with the plasma-treated titanium surface. This difference may be attributed to increased surface roughness and changes in titanium oxide layer thickness. 相似文献
143.
Andrighetti-Fröhner CR de Oliveira KN Gaspar-Silva D Pacheco LK Joussef AC Steindel M Simões CM de Souza AM Magalhaes UO Afonso IF Rodrigues CR Nunes RJ Castro HC 《European journal of medicinal chemistry》2009,44(2):755-763
Despite clinical importance of leishmaniasis, an infectious disease that affects 12 thousand million people in 88 countries, the treatment is still unsatisfactory due to its limited efficacy, cost expensive and undesirable side effects. Aiming to develop new antileishmanial lead compounds, we used a rational approach to synthesize a new set of sulfonamide 4-methoxychalcone derivatives (3a-3i) and evaluate the sulfonamide and methoxy moieties as promising adding-groups to chalcones. For that purpose we tested this new set against Leishmania braziliensis promastigotes and intracellular amastigotes and determined its cell toxicity profile. Interestingly all compounds presented a concentration-dependent antileishmanial profile and the benzylamino derivative (3i) showed a biological activity better than pentamidine. None of these compounds affected Trypanosoma cruzi epimastigotes, which suggests a specific antileishmanial profile. The structure-activity analysis of these sulfonamide 4-methoxychalcone derivatives pointed the molecular volume, the HOMO density concentrated in the chalcone moiety and the conformational structure of the compounds as important structural and stereoelectronic features for the antileishmanial activity. In addition, these compounds also fulfilled Lipinski rule of 5 and presented druglikeness similar to antileishmanial drugs. Altogether these results point the sulfonamide 4-methoxychalcone derivatives as potential lead compounds for designing new candidates for leishmaniasis treatment. 相似文献
144.
Silva AC Lee JH Wu CW Tucciarone J Pelled G Aoki I Koretsky AP 《Journal of neuroscience methods》2008,167(2):246-257
Changes in manganese-enhanced MRI (MEMRI) contrast across the rodent somatosensory cortex were compared to the cortical laminae as identified by tissue histology and administration of an anatomical tracer to cortex and thalamus. Across the cortical thickness, MEMRI signal intensity was low in layer I, increased in layer II, decreased in layer III until mid-layer IV, and increased again, peaking in layer V, before decreasing through layer VI. The reeler mouse mutant was used to confirm that the cortical alternation in MEMRI contrast was related to laminar architecture. Unlike in wild-type mice, the reeler cortex showed no appreciable changes in MEMRI signal, consistent with absence of cortical laminae in histological slides. The tract tracing ability of MEMRI was used to further confirm assignments and demonstrate laminar specificity. Twelve to 16 h after stereotaxic injections of MnCl(2) to the ventroposterior thalamic nuclei, an overall increase in signal intensity was detected in primary somatosensory cortex compared to other brain regions. Maximum intensity projection images revealed a distinctly bright stripe located 600-700 microm below the pial surface, in layer IV. The data show that both systemic and tract tracing forms of MEMRI are useful for studying laminar architecture in the brain. 相似文献
145.
BACKGROUND: Infections after liver transplantations are the most important cause of morbi-mortality. In this study, we assessed the main characteristics of these infections in a southern Brazilian university hospital. METHODS: We conducted a retrospective cohort with 55 patients who underwent orthotopic liver transplantation between 1996 and 2000 in the "Hospital de Clínicas de Porto Alegre", Porto Alegre, RS, Brazil, to characterize the infections that occurred in the group. RESULTS: One or more infections (average 2.10) were diagnosed in 47 patients, especially during the first month after transplantation. The most common were bacteremia, intra-abdominal infections and pneumonia, predominantly with bacteria, especially Staphylococcus sp (and particularly S. aureus) and E. coli. The mortality rate attributed to infections was high: 17 cases of all deaths (total 27 deaths). Significant risk factors for infections included reoperation, diabetes, biliary stenosis and higher Child-Pugh scores. CONCLUSION: Infections remain a severe threat in liver transplant patients, and special efforts should be made to prevent and manage them correctly. 相似文献
146.
147.
Pedro M. Rodrigues Marta B. Afonso André L. Simão Tawhidul Islam Maria M. Gaspar Colm J. O'Rourke Monika Lewinska Jesper B. Andersen Enara Arretxe Cristina Alonso Álvaro Santos-Laso Laura Izquierdo-Sanchez Raúl Jimenez-Agüero Emma Eizaguirre Luis Bujanda Maria J. Pareja Carina Prip-Buus Jesus M. Banales Cecília M. P. Rodrigues Rui E. Castro 《Liver international》2023,43(10):2256-2274
Background and Aims
The mechanisms governing the progression of non-alcoholic fatty liver disease (NAFLD) towards steatohepatitis (NASH) and hepatocellular carcinoma (HCC) remain elusive. Here, we evaluated the role of hsa-miRNA-21-5p in NASH-related hepatocarcinogenesis.Methods
Hepatic hsa-miR-21-5p expression was evaluated in two cohorts of patients with biopsy-proven NAFLD (n = 199) or HCC (n = 366 HCC and n = 11 NAFLD-HCC). Serum/liver metabolomic profiles were correlated with hsa-miR-21-5p in NAFLD obese patients. Wild-type (WT) and Mir21 KO mice were fed a choline-deficient, amino acid-defined (CDAA) diet for 32 and 66 weeks to induce NASH and NASH-HCC, respectively.Results
In obese individuals, hsa-miR-21-5p expression increased with NAFLD severity and associated with a hepatic lipotoxic profile. CDAA-fed WT mice displayed increased hepatic mmu-miR-21-5p levels and progressively developed NASH and fibrosis, with livers presenting macroscopically discernible pre-neoplastic nodules, hyperplastic foci and deregulated cancer-related pathways. Mir21 KO mice exhibited peroxisome-proliferator-activated receptor α (PPARα) activation, augmented mitochondrial activity, reduced liver injury and NAS below the threshold for NASH diagnosis, with the pro-inflammatory/fibrogenic milieu reversing to baseline levels. In parallel, Mir21 KO mice displayed reduced number of pre-neoplastic nodules, hepatocyte proliferation and activation of oncogenic signalling, being protected from NASH-associated carcinogenesis. The hsa-miRNA-21-5p/PPARα pathway was similarly deregulated in patients with HCC- or NASH-related HCC, correlating with HCC markers and worse prognosis.Conclusions
Hsa-miR-21-5p is a key inducer of whole-spectrum NAFLD progression, from simple steatosis to NASH and NASH-associated carcinogenesis. The inhibition of hsa-miR-21-5p, leading to a pro-metabolic profile, might constitute an appealing therapeutic approach to ameliorate NASH and prevent progression towards HCC. 相似文献148.
Afonso RC Hidalgo R Paes AT Zurstrassen MP Fonseca LE Pandullo FL Rezende MB Meira-Filho SP Ferraz-Neto BH 《Transplantation proceedings》2008,40(3):800-801
There are various options to help overcome the organ shortage, including performing transplants using grafts from marginal donors with characteristics previously described as unacceptable because of the high risk of graft failure. Nowadays, expanded criteria donors for liver transplantation (OLT) is a strategy used routinely by many teams. Some donor features have been suggested to jeopardize initial function or survival; when these features are aggregated, they may impact prognosis. The aim of this study was to evaluate the impact of donor risk factors on early patient survival and retransplantation. Donor risk factors were considered to be older than 60 years, body mass index > 30, serum sodium level > 155 mEq/L, cold ischemia time > 12 hours, and intensive care unit stay > 4 days. We prospectively recorded data from 139 patients who underwent 152 OLT from March 2003 to May 2007. Patients were classified into four groups: I, no risk factors; II, one risk factor; III, two risk factors; IV, three or more risk factors. Retransplantation or OLT due to acute liver failure was considered to be an exclusion criterion. Early overall survival rate was 83.76%; 12 retransplantations were required (10.25%). Comparing the four groups, patient survivals (P = .41) and retransplantation rates (P = .518) were similar. In conclusion, cumulative risk factors showed no impact on early (30-day) recipient survival and or on the necessity of retransplantation after OLT. 相似文献
149.
Afonso V Champy R Mitrovic D Collin P Lomri A 《Joint, bone, spine : revue du rhumatisme》2007,74(4):324-329
Reactive oxygen species (ROS) are produced in many normal and abnormal processes in humans, including atheroma, asthma, joint diseases, aging, and cancer. The superoxide anion O(2)(-) is the main ROS. Increased ROS production leads to tissue damage associated with inflammation. Superoxide dismutases (SODs) convert superoxide to hydrogen peroxide, which is then removed by glutathione peroxidase or catalase. Thus, SODs prevent the formation of highly aggressive ROS, such as peroxynitrite or the hydroxyl radical. Experimental models involving SOD knockout or overexpression are beginning to shed light on the pathophysiological role of SOD in humans. Although the antiinflammatory effects of exogenous native SOD (orgotein) are modest, synthetic SOD mimetics hold considerable promise for modulating the inflammatory response. In this review, we discuss new knowledge about the role of the superoxide anion and its derivates as mediators of inflammation and the role of SODs and SOD mimetics as antioxidant treatments in joint diseases such as rheumatoid arthritis, osteoarthritis, and crystal-induced arthropathies. 相似文献
150.
C Amaro I Freitas P Lamarão A Afonso M Skrzypczak W Heinritz 《Journal of the European Academy of Dermatology and Venereology》2010,24(7):844-846
Background Trichoepitheliomas are benign neoplasms with follicular differentiation. They may present as a solitary lesion or as multiple lesions. Multiple trichoepitheliomas are inherited in an autosomal dominant pattern within families, with both variable penetrance and expressivity. Recent investigations support that mutations in CYLD, the gene affected in familial cylindromatosis as well as in Brooke–Spiegler syndrome, are also responsible for multiple trichoepitheliomas. Objective The authors report the case of a 9‐year‐old African girl with multiple facial trichoepitheliomas in whom a mutation in the CYLD gene was hypothesised. Materials and methods After genomic DNA extraction from the peripheral blood, a molecular analysis of the CYLD gene was performed by PCR, DHPLC and automated sequencing. Results A novel heterozygous mutation in exon 18 of the CYLD gene (c.2449delT) was identified, with a deletion of one nucleotide resulting in a premature translational termination codon at amino acid position 831 on the affected allele (p.Cys817Valfs X15). Conclusions The predominating tumours define the classification of these three entities. Nevertheless, studies suggest that they can simply represent phenotypic variations of the same disease spectrum, sharing common genetic mutations. 相似文献