94 resultados para Ricardo Rojas


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The cranial base, composed of the midline and lateral basicranium, is a structurally important region of the skull associated with several key traits, which has been extensively studied in anthropology and primatology. In particular, most studies have focused on the association between midline cranial base flexion and relative brain size, or encephalization. However, variation in lateral basicranial morphology has been studied less thoroughly. Platyrrhines are a group of primates that experienced a major evolutionary radiation accompanied by extensive morphological diversification in Central and South America over a large temporal scale. Previous studies have also suggested that they underwent several evolutionarily independent processes of encephalization. Given these characteristics, platyrrhines present an excellent opportunity to study, on a large phylogenetic scale, the morphological correlates of primate diversification in brain size. In this study we explore the pattern of variation in basicranial morphology and its relationship with phylogenetic branching and with encephalization in platyrrhines. We quantify variation in the 3D shape of the midline and lateral basicranium and endocranial volumes in a large sample of platyrrhine species, employing high-resolution CT-scans and geometric morphometric techniques. We investigate the relationship between basicranial shape and encephalization using phylogenetic regression methods and calculate a measure of phylogenetic signal in the datasets. The results showed that phylogenetic structure is the most important dimension for understanding platyrrhine cranial base diversification; only Aotus species do not show concordance with our molecular phylogeny. Encephalization was only correlated with midline basicranial flexion, and species that exhibit convergence in their relative brain size do not display convergence in lateral basicranial shape. The evolution of basicranial variation in primates is probably more complex than previously believed, and understanding it will require further studies exploring the complex interactions between encephalization, brain shape, cranial base morphology, and ecological dimensions acting along the species divergence process.

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The evolution and population dynamics of avian coronaviruses (AvCoVs) remain underexplored. In the present study, in-depth phylogenetic and Bayesian phylogeographic studies were conducted to investigate the evolutionary dynamics of AvCoVs detected in wild and synanthropic birds. A total of 500 samples, including tracheal and cloacal swabs collected from 312 wild birds belonging to 42 species, were analysed using molecular assays. A total of 65 samples (13%) from 22 bird species were positive for AvCoV. Molecular evolution analyses revealed that the sequences from samples collected in Brazil did not cluster with any of the AvCoV S1 gene sequences deposited in the GenBank database. Bayesian framework analysis estimated an AvCoV strain from Sweden (1999) as the most recent common ancestor of the AvCoVs detected in this study. Furthermore, the analysis inferred an increase in the AvCoV dynamic demographic population in different wild and synanthropic bird species, suggesting that birds may be potential new hosts responsible for spreading this virus.

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Traveling wave ion mobility mass spectrometry (TWIM-MS) is shown to be able to separate and characterize several isomeric forms of diterpene glycosides stevioside (Stv) and rebaudioside A (RebA) that are cationized by Na(+) and K(+) at different sites. Determination and characterization of these coexisting isomeric species, herein termed catiomers, arising from cationization at different and highly competitive coordinating sites, is particularly challenging for glycosides. To achieve this goal, the advantage of using CO2 as a more massive and polarizable drift gas, over N2 , was demonstrated. Post-TWIM-MS/MS experiments were used to confirm the separation. Optimization of the possible geometries and cross-sectional calculations for mobility peak assignments were also performed. Copyright © 2015 John Wiley & Sons, Ltd.

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The present review addresses certain important aspects regarding nanoparticles and the environment, with an emphasis on plant science. The production and characterization of nanoparticles is the focus of this review, providing an idea of the range and the consolidation of these aspects in the literature, with modifications on the routes of synthesis and the application of the analytical techniques for characterization of the nanoparticles (NPs). Additionally, aspects related to the interaction between the NPs and plants, their toxicities, and the phytoremediation process, among others, are also discussed. Future trends are also presented, supplying evidence for certain possibilities regarding new research involving nanoparticles and plants.

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To determine the effects of radiotherapy on salivary BPIFA expression and to investigate the role of BPIFA in the development of known radiotherapy side effects. Unstimulated whole-mouth saliva was collected from 45 cancer patients (1 week before treatment, during the treatment, and 1 week after completion of radiotherapy) and from 20 controls. BPIFA1 and BPIFA2 expression was detected by western blotting and analyzed along with clinicopathologic data and side effects from the radiotherapy. A facial radiation field was associated with lower salivary flow during and after radiotherapy and correlated with side effects, mainly mucositis. Salivary BPIFA1 expression levels were similar between the control group and the patient group before treatment. On the other hand, BPIFA2 levels were higher in the patient group before treatment compared with the control group. BPIFA concentration was modified by radiotherapy as BPIFA1 levels increased (P = .0081) and BPIFA2 decreased (P < .0001). Higher levels of BPIFA1 were associated with the presence of mucositis (P = .0363) and its severity (P = .0500). The present study found that levels of BPIFA1 and glycosylated forms of BPIFA2 are affected by radiotherapy, suggesting that these proteins may play a role in the oral microenvironment in irradiated patients with head and neck cancer.

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Avian Pathogenic Escherichia coli (APEC) strains are extra-intestinal E. coli that infect poultry and cause diseases. Nitrite is a central branch-point in bacterial nitrogen metabolism and is used as a cytotoxin by macrophages. Unlike nitric oxide (NO), nitrite cannot diffuse across bacterial membrane cells. The NirC protein acts as a specific channel to facilitate the transport of nitrite into Salmonella and E. coli cells for nitrogen metabolism and cytoplasmic detoxification. NirC is also required for the pathogenicity of Salmonella by downregulating the production of NO by the host macrophages. Based on an in vitro microarray that revealed the overexpression of the nirC gene in APEC strain SCI-07, we constructed a nirC-deficient SCI-07 strain (ΔnirC) and evaluated its virulence potential using in vivo and in vitro assays. The final cumulative mortalities caused by mutant and wild-type (WT) were similar; while the ΔnirC caused a gradual increase in the mortality rate during the seven days recorded, the WT caused mortality up to 24h post-infection (hpi). Counts of the ΔnirC cells in the spleen, lung and liver were higher than those of the WT after 48 hpi but similar at 24 hpi. Although similar number of ΔnirC and WT cells was observed in macrophages at 3 hpi, there was higher number of ΔnirC cells at 16 hpi. The cell adhesion ability of the ΔnirC strain was about half the WT level in the presence and absence of alpha-D-mannopyranoside. These results indicate that the nirC gene influences the pathogenicity of SCI-07 strain.

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BACKGROUND: Strictureplasty is an alternative surgical procedure for Crohn?s disease, particulary in patients with previous resections or many intestinal stenosis. AIM: To analyze surgical complications and clinical follow-up in patients submitted to strictureplasty secondary to Crohn?s disease. METHODS: Twenty-eight patients (57.1% male, mean age 33.3 years, range 16-54 years) with Crohn?s disease and intestinal stenosis (small bowel, ileocecal region and ileocolic anastomosis) were submitted to strictureplasty, at one institution, between September 1991 and May 2004. Thirteen patients had previous intestinal resections. The mean follow-up was 58.1 months. A total of 116 strictureplasties were done (94 Heineke-Mikulicz - 81%, 15 Finney - 13%, seven side-to-side ileocolic strictureplasty - 6%). Three patients were submitted to strictureplasty at two different surgical procedures and two in three procedures. RESULTS: Regarding to strictureplasty, postoperative complication rate was 25% and mortality was 3.6%. Early local complication rate was 57.1%, with three suture leaks (10.7%) and late complication was present in two patients, both with incisional hernial and enterocutaneous fistulas (28.6%). Patients remained hospitalized during a medium time of 12.4 days. Clinical and surgical recurrence rates were 63% and 41%, respectively. Among the patients submitted to another surgery, two patients had two more operations and one had three. Recurrence rate at strictureplasty site was observed in 3.5%, being Finney technique the commonest one. Presently, 19 patients had been asymptomatic with the majority of them under medical therapy. CONCLUSION: Strictureplasties have low complication rates, in spite of having been done at compromised site, with long term pain relief. Considering the clinical course of Crohn?s disease, with many patients being submitted to intestinal resections, strictureplasties should be considered as an effective surgical treatment to spare long intestinal resections.

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BACKGROUND: Restorative proctocolectomy is the procedure of choice to treat familial adenomatous polyposis, however it can be associated to short-term and long-term postoperative complications. AIM: To evaluate the occurrence of complications related to the surgical treatment of familial adenomatous polyposis with ileal pouch technique. METHODS: Retrospective study of 69 patients with familial adenomatous polyposis after rectocolectomy with ileal reservoir between 1984 and 2006, operated on Coloproctology Group, Medical Sciences Faculty, State University of Campinas, Campinas, SP, Brazil. The median follow-up period was 82 (2-280) months. Data obtained were surgical techniques and postoperative complications. RESULTS: The morbidity and mortality were 63.8% and 2.9%, respectively. The most frequent complications were small-bowel obstruction (17.4%), anastomotic stricture (15.9%) and pelvic sepsis (10.1%). Acute ischemia of the ileal pouch (4.3%), pouchitis (2.9%) and ileal pouch-related fistula (2.9%) had poorer frequency than others. CONCLUSIONS: The morbid-mortality was similar to the literature?s data and it is acceptable for a complex surgery in two terms like the ileal reservoir-anal anastomosis. The small-bowel obstruction was the most frequent complication. However, ischemia of the reservoir, pouchitis and pelvic sepsis were important complications and was related to the failure of the ileal reservoir.

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BACKGROUND: Total rectocolectomy and ileal pouch-anal anastomosis is the choice surgical procedure for patients with ulcerative colitis. In cases of Crohn's disease post-operative diagnosis, it can be followed by pouch failure. AIM: To evaluate ileal pouch-anal anastomosis long-term outcome in patients with Crohn's disease. METHODS: Between February 1983 and March 2007, 151 patients were submitted to ileal pouch-anal anastomosis by Campinas State University Colorectal Unit, Campinas, SP, Brazil, 76 had pre-operative ulcerative colitis diagnosis and 11 had post-operative Crohn's disease diagnosis. Crohn's disease diagnosis was made by histopathological biopsies in nine cases, being one in surgical specimen, two cases in rectal stump, small bowel in two cases, ileal pouch in three and in perianal abscess in one of them. The median age was 30.6 years and eight (72.7%) were female. RESULTS: All patients had previous ulcerative colitis diagnosis and in five cases emergency colectomy was done by toxic megacolon. The mean time until of Crohn's disease diagnosis was 30.6 (6-80) months after ileal pouch-anal anastomosis. Ileostomy closure was possible in 10 cases except in one that had ileal pouch fistula, perianal disease and small bowel involvement. In the long-term follow-up, three patients had perineal fistulas and one had also a pouch-vaginal fistula. All of them were submitted to a new ileostomy and one had the pouch excised. Another patient presented pouch-vaginal fistula which was successfully treated by mucosal flap. Three patients had small bowel involvement and three others, pouch involvement. All improved with medical treatment. Presently, the mean follow-up is 76.5 months and all patients are in clinical remission, and four have fecal diversion. The remaining patients have good functional results with 6-10 bowel movements/day. CONCLUSION: Crohn's disease diagnosis after ileal pouch-anal anastomosis for ulcerative colitis may be usual and later complications such fistulas and stenosis are common. However, when left in situ ileal pouch is associated with good function.

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Two cases of giant intracavernous aneurysms treated by high flow bypass with saphenous vein graft between the external carotid artery (ECA) and branches of the middle cerebral artery (MCA) are presented. Very often these aneurysms are unclippable because they are fusiform or have a large neck. Occlusion of the internal carotid artery (ICA) is the treatment of choice in many cases. This procedure has however a high risk of brain infarction. Revascularization of the brain by extra-intracranial anastomosis between the superficial temporal artery (STA) and branches of the MCA is frequently performed. This procedure provides however a low flow bypass and brain infarction may occur. We report two cases of giant cavernous sinus aneurysms treated by high flow bypass and endovascular balloon occlusion of the ICA. Immediate high flow revascularization of MCA branches was achieved and the patients showed no ischemic events. Follow-up of 8 and 14 months after operation shows patency of the venous graft and no neurological deficits. Angiographic control examination showed complete aneurysm occlusion in both cases.

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Administration of fractionated doses of irradiation is part of the adjutant therapy for CNS tumours such as craniopharyngiomas and pituitary adenomas. It can maximise cure rates or expand symptom-free period. Among the adverse effects of radiotherapy, the induction of a new tumour within the irradiated field has been frequently described. The precise clinical features that correlate irradiation and oncogenesis are not completely defined, but some authors have suggested that tumors are radiation induced when they are histologically different from the treated ones, arise in greater frequency in irradiated patients than among normal population and tend to occur in younger people with an unusual aggressiveness. In this article, we report a case of a papillary astrocytoma arising in a rather unusual latency period following radiotherapy for craniopharyngioma.

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We report the case of a 73-year-old female who presented facial numbness and pain in the first division of the trigeminal nerve, ptosis, diplopia and visual loss on the right side for the previous four months. The neurological, radiological and histological examination demonstrated a rare case of invasive fungal aspergillosis of the central nervous system, causing orbital apex syndrome, later transformed in temporal brain abscess. She died ten months later due to respiratory and renal failure in spite of specific antimycotic therapy.

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Nitric oxide ( NO) is a substance that acts as a second-messenger and is associated with a number of important physiological functions such as regulation of the vascular tonus, immune modulation and neurotransmission. As a physiological mediator, alteration of its concentration level may cause pathophysiological disfunctions such as hypertension, septic shock and impotence. Possible therapeutic approaches are being developed to control NO levels in vivo. We review herein the main physical and chemical properties of NO, its biological functions and available chemical interventions to reduce and increment its physiological concentration levels. Recent developments in the field are also highlighted.

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MIPs are synthetic polymers that are used as biomimetic materials simulating the mechanism verified in natural entities such as antibodies and enzymes. Although MIPs have been successfully used as an outstanding tool for enhancing the selectivity or different analytical approaches, such as separation science and electrochemical and optical sensors, several parameters must be optimized during their synthesis. Therefore, the state-of-the-art of MIP production as well as the different polymerization methods are discussed. The potential selectivity of MIPs in the extraction and separation techniques focusing mainly on environmental, clinical and pharmaceutical samples as applications for analytical purposes is presented.