In vivo electrochemical characterization and inflammatory response of multiwalled carbon nanotube-based electrodes in rat hippocampus

Stimulating neural electrodes are required to deliver charge to an environment that presents itself as hostile. The electrodes need to maintain their electrical characteristics (charge and impedance) in vivo for a proper functioning of neural prostheses. Here we design implantable multi-walled carbon nanotubes coating for stainless steel substrate electrodes, targeted at wide frequency stimulation of deep brain structures. In well-controlled, low-frequency stimulation acute experiments, we show that multi-walled carbon nanotube electrodes maintain their charge storage capacity (CSC) and impedance in vivo. The difference in average CSCs (n = 4) between the in vivo (1.111 mC cm(-2)) and in vitro (1.008 mC cm(-2)) model was statistically insignificant (p > 0.05 or P-value = 0.715, two tailed). We also report on the transcription levels of the pro-inflammatory cytokine IL-1 beta and TLR2 receptor as an immediate response to low-frequency stimulation using RT-PCR. We show here that the IL-1 beta is part of the inflammatory response to low-frequency stimulation, but TLR2 is not significantly increased in stimulated tissue when compared to controls. The early stages of neuroinflammation due to mechanical and electrical trauma induced by implants can be better understood by detection of pro-inflammatory molecules rather than by histological studies. Tracking of such quantitative response profits from better analysis methods over several temporal and spatial scales. Our results concerning the evaluation of such inflammatory molecules revealed that transcripts for the cytokine IL-1 beta are upregulated in response to low-frequency stimulation, whereas no modulation was observed for TLR2. This result indicates that the early response of the brain to mechanical trauma and low-frequency stimulation activates the IL-1 beta signaling cascade but not that of TLR2.

Surgical management of glomus jugulare tumors: a proposal for approach selection based on tumor relationships with the facial nerve Clinical article

Object. The goal of this paper is to analyze the extension and relationships of glomus jugulare tumor with the temporal bone and the results of its surgical treatment aiming at preservation of the facial nerve. Based on the tumor extension and its relationships with the facial nerve, new criteria to be used in the selection of different surgical approaches are proposed. Methods. Between December 1997 and December 2007, 34 patients (22 female and 12 male) with glomus jugulare tumors were treated. Their mean age was 48 years. The mean follow-up was 52.5 months. Clinical findings included hearing loss in 88%, swallowing disturbance in 50%, and facial nerve palsy in 41%. Magnetic resonance imaging demonstrated a mass in the jugular foramen in all cases, a mass in the middle ear in 97%, a cervical mass in 85%, and an intradural mass in 41%. The tumor was supplied by the external carotid artery in all cases, the internal carotid artery in 44%, and the vertebral artery in 32%. Preoperative embolization was performed in 15 cases. The approach was tailored to each patient, and 4 types of approaches were designed. The infralabyrinthine retrofacial approach (Type A) was used in 32.5%; infralabyrinthine pre- and retrofacial approach without occlusion of the external acoustic meatus (Type B) in 20.5%; infralabyrinthine pre- and retrofacial approach with occlusion of the external acoustic meatus (Type C) in 41 W. and the infralabyrinthine approach with transposition of the facial nerve and removal of the middle ear structures (Type D) in 6% of the patients. Results. Radical removal was achieved in 91% of the cases and partial removal in 9%. Among 20 patients without preoperative facial nerve dysfunction, the nerve was kept in anatomical position in 19 (95%), and facial nerve function was normal during the immediate postoperative period in 17 (85%). Six patients (17.6%) had a new lower cranial nerve deficit, but recovery of swallowing function was adequate in all cases. Voice disturbance remained in all 6 cases. Cerebrospinal fluid leakage occurred in 6 patients (17.6%), with no need for reoperation in any of them. One patient died in the postoperative period due to pulmonary complications. The global recovery, based on the Karnofsky Performance Scale (KPS), was 100% in 15% of the patients, 90% in 45%, 80% in 33%, and 70% in 6%. Conclusions. Radical removal of glomus jugulare tumor can be achieved without anterior transposition of the facial nerve. The extension of dissection, however, should be tailored to each case based on tumor blood supply, preoperative symptoms, and tumor extension. The operative field provided by the retrofacial infralabyrinthine approach, or the pre- and retrofacial approaches. with or without Closure of the external acoustic meatus, allows a wide exposure of the jugular foramen area. Global functional recovery based on the KPS is acceptable in 94% of the patients. (DOI: 10.3171/2008.10.JNS08612)

Supporting content-based image retrieval and computer-aided diagnosis systems with association rule-based techniques

In this work, we take advantage of association rule mining to support two types of medical systems: the Content-based Image Retrieval (CBIR) systems and the Computer-Aided Diagnosis (CAD) systems. For content-based retrieval, association rules are employed to reduce the dimensionality of the feature vectors that represent the images and to improve the precision of the similarity queries. We refer to the association rule-based method to improve CBIR systems proposed here as Feature selection through Association Rules (FAR). To improve CAD systems, we propose the Image Diagnosis Enhancement through Association rules (IDEA) method. Association rules are employed to suggest a second opinion to the radiologist or a preliminary diagnosis of a new image. A second opinion automatically obtained can either accelerate the process of diagnosing or to strengthen a hypothesis, increasing the probability of a prescribed treatment be successful. Two new algorithms are proposed to support the IDEA method: to pre-process low-level features and to propose a preliminary diagnosis based on association rules. We performed several experiments to validate the proposed methods. The results indicate that association rules can be successfully applied to improve CBIR and CAD systems, empowering the arsenal of techniques to support medical image analysis in medical systems. (C) 2009 Elsevier B.V. All rights reserved.

Evaluation of Adult Chronic Chagas` Heart Disease Diagnosis by Molecular and Serological Methods

Chagas` disease caused by Trypanosoma cruzi is endemic in Latin America. T. cruzi presents heterogeneous populations and comprises two main genetic lineages, named T. cruzi I and T. cruzi II. Diagnosis in the chronic phase is based on conventional serological tests, including indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA), and diagnosis in the acute phase based on parasitological methods, including hemoculture. The objective of this study was to evaluate the diagnostic procedures of Chagas` disease in adult patients in the chronic phase by using a PCR assay and conventional serological tests, including TESA-blot as the gold standard. Samples were obtained from 240 clinical chronic chagasic patients. The sensitivities, compared to that of TESA-blot, were 70% for PCR using the kinetoplast region, 75% for PCR using the nuclear repetitive region, 99% for IIF, and 95% for ELISA. According to the serological tests results, we recommend that researchers assess the reliability and sensitivity of the commercial kit Chagatest ELISA recombinant, version 3.0 (Chagatest Rec v3.0; Wiener Lab, Rosario, Argentina), due to the lack of sensitivity. Based on our analysis, we concluded that PCR cannot be validated as a conventional diagnostic technique for Chagas` disease. These data have been corroborated by low levels of concordance with serology test results. It is recommended that PCR be used only for alternative diagnostic support. Using the nuclear repetitive region of T. cruzi, PCR could also be applicable for monitoring patients receiving etiologic treatment.

Whole-Brain Voxel-Based Morphometry in Kallmann Syndrome Associated with Mirror Movements

BACKGROUND AND PURPOSE: There are 2 main hypotheses concerning the cause of mirror movements (MM) in Kallmann syndrome (KS): abnormal development of the primary motor system, involving the ipsilateral corticospinal tract, and lack of contralateral motor cortex inhibitory mechanisms, mainly through the corpus callosum. The purpose of our study was to determine white and gray matter volume changes in a KS population by using optimized voxel-based morphometry (VBM) and to investigate the relationship between the abnormalities and the presence of MM, addressing the 2 mentioned hypotheses. MATERIALS AND METHODS: T1-weighted volumetric images from 21 patients with KS and 16 matched control subjects were analyzed with optimized VBM. Images were segmented and spatially normalized, and these deformation parameters were then applied to the original images before the second segmentation. Patients were divided into groups with and without MM, and a t test statistic was then applied on a voxel-by-voxel basis between the groups and controls to evaluate significant differences. RESULTS: When considering our hypothesis a priori, we found that 2 areas of increased gray matter volume, in the left primary motor and sensorimotor cortex, were demonstrated only in patients with MM, when compared with healthy controls. Regarding white matter alterations, no areas of altered volume involving the corpus callosum or the projection of the corticospinal tract were demonstrated. CONCLUSION: The VBM study did not show significant white matter changes in patients with KS but showed gray matter alterations in keeping with a hypertrophic response to a deficient pyramidal decussation in patients with MM. In addition, gray matter alterations were observed in patients without MM, which can represent more complex mechanisms determining the presence or absence of this symptom.

Evaluation of computational methods for the reconstruction of HLA haplotypes

Human leukocyte antigen (HLA) haplotypes are frequently evaluated for population history inferences and association studies. However, the available typing techniques for the main HLA loci usually do not allow the determination of the allele phase and the constitution of a haplotype, which may be obtained by a very time-consuming and expensive family-based segregation study. Without the family-based study, computational inference by probabilistic models is necessary to obtain haplotypes. Several authors have used the expectation-maximization (EM) algorithm to determine HLA haplotypes, but high levels of erroneous inferences are expected because of the genetic distance among the main HLA loci and the presence of several recombination hotspots. In order to evaluate the efficiency of computational inference methods, 763 unrelated individuals stratified into three different datasets had their haplotypes manually defined in a family-based study of HLA-A, -B, -DRB1 and -DQB1 segregation, and these haplotypes were compared with the data obtained by the following three methods: the Expectation-Maximization (EM) and Excoffier-Laval-Balding (ELB) algorithms using the arlequin 3.11 software, and the PHASE method. When comparing the methods, we observed that all algorithms showed a poor performance for haplotype reconstruction with distant loci, estimating incorrect haplotypes for 38%-57% of the samples considering all algorithms and datasets. We suggest that computational haplotype inferences involving low-resolution HLA-A, HLA-B, HLA-DRB1 and HLA-DQB1 haplotypes should be considered with caution.

MHM assay: molecular sexing based on the sex-specific methylation pattern of the MHM region in chickens

Bird sex determination using molecular methods has proved to be a valuable tool in different studies. Although it is possible to sex most birds by coupling the CHD assay with others available methods, no sex-determining gene like SRY in mammalians has been identified in birds. The male hypermethylated (MHM) region on the Z chromosome has been found to be hypermethylated in males and hypomethylated in females in birds of the order Galliformes. We analyzed the DNA from feathers of 50 adult chickens to verify the methylation pattern of the MHM region by PCR and the restriction enzyme HpaII (a method named MHM assay). The results, visualized in agarose gel, were compared with PCR amplification of the CHD-Z and CHD-W genes (polyacrylamide gel) and with the birds` phenotype. All males (25) showed hypermethylation of the MHM region, and all females (25) showed hypomethylation. The sexing by MHM assay was in according with phenotype and CHD sexing. To our knowledge, this is the first study that uses the MHM region for sexing birds. Although the real role of the MHM region in the sex determination is still unclear, this could be a universal marker for sexing birds and may be involved in sex determination by its influence on transcriptional processes. The MHM assay could be a good alternative for CHD assay in developmental studies.

Who were the male founders of rural Brazilian Afro-derived communities? A proposal based on three populations

Background: Brazilian Quilombos are Afro-derived communities founded mainly by fugitive slaves between the 16(th) and 19(th) centuries; they can be recognized today by ancestral and cultural characteristics. Each of these remnant communities, however, has its own particular history, which includes the migration of non-African derived people. Methods: The present work presents a proposal for the origin of the male founder in Brazilian quilombos based on Y-haplogroup distribution. Y haplogroups, based on 16 binary markers (92R7, SRY2627, SRY4064, SRY10831.1 and .2, M2, M3, M09, M34, M60, M89, M213, M216, P2, P3 and YAP), were analysed for 98 DNA samples from genetically unrelated men from three rural Brazilian Afro-derived communities-Mocambo, Rio das Ras and Kalunga-in order to estimate male geographic origin. Results: Data indicated significant differences among these communities. A high frequency of non-African haplogroups was observed in all communities. Conclusions: This observation suggested an admixture process that has occurred over generations and directional mating between European males and African female slaves that must have occurred on farms before the slaves escaped. This means that the admixture occurred before the slaves escaped and the foundation of the quilombo.

Risk of Potential Drug-Drug Interactions among Brazilian Elderly A Population-Based, Cross-Sectional Study

Background: Drug-drug interactions (DDIs) are one of the main causes of adverse reactions related to medications, being responsible for up to 23% of hospital admissions. However, only a few studies have evaluated this problem in elderly Brazilians. Objectives: To determine the prevalence of potential DDIs (PDDIs) in community-dwelling elderly people in Brazil, analyse these interactions with regard to severity and clinical implications, and identify associated factors. Methods: A population-based cross-sectional study was carried out involving 2143 elderly (aged 60 years) residents of the metropolitan area of Sao Paulo, Brazil. Data were obtained from the SABE (Saude, Bem estar e Envelhecimento [Health, Well-Being, and Aging]) survey, which is a multicentre study carried out in seven countries of Latin America and the Caribbean, coordinated by the Pan-American Health Organization. PDDIs were analysed using a computerized program and categorized according to level of severity, onset, mechanism and documentation in the literature. The STATA software statistical package was used for data analysis, and logistic regression was conducted to determine whether variables were associated with PDDIs. Results: Analysis revealed that 568 (26.5%) of the elderly population included in the study were taking medications that could lead to a DDI. Almost two-thirds (64.4%) of the elderly population exposed to PDDIs were women, 50.7% were aged >= 75 years, 71.7% reported having fair or poor health and 65.8% took 2-5 medications. A total of 125 different PDDIs were identified; the treatment combination of an ACE inhibitor with a thiazide or loop diuretic (associated with hypotension) was the most frequent cause of PDDIs (n=322 patients; 56.7% of individuals with PDDIs). Analysis of the PDDIs revealed that 70.4% were of moderate severity, 64.8% were supported by good quality evidence and 56.8% were considered of delayed onset. The multivariate analysis showed that the risk of a PDDI was significantly increased among elderly individuals using six or more medications (odds ratio [OR] 3.37) and in patients with hypertension (OR 2.56), diabetes mellitus (OR 1.73) or heart problems (OR 3.36). Conclusions: Approximately one-quarter of the elderly population living in Sao Paulo could be taking two or more potentially interacting medicines. Polypharmacy predisposes elderly individuals to PDDIs. More than half of these drug combinations (57.6%, n = 72) were part of commonly employed treatment regimens and may be responsible for adverse reactions that compromise the safety of elderly individuals, especially at home. Educational initiatives are needed to avoid unnecessary risks.

Stroke awareness in Brazil - Alarming results in a community-based study

Background and Purpose-Stroke is the leading cause of death in Brazil. This community-based study assessed lay knowledge about stroke recognition and treatment and risk factors for cerebrovascular diseases and activation of emergency medical services in Brazil. Methods-The study was conducted between July 2004 and December 2005. Subjects were selected from the urban population in transit about public places of 4 major Brazilian cities: S (a) over tildeo Paulo, Salvador, Fortaleza, and Ribeir (a) over tildeo Preto. Trained medical students, residents, and neurologists interviewed subjects using a structured, open-ended questionnaire in Portuguese based on a case presentation of a typical patient with acute stroke at home. Results-Eight hundred fourteen subjects were interviewed during the study period (53.9% women; mean age, 39.2 years; age range, 18 to 80 years). There were 28 different Portuguese terms to name stroke. Twenty-two percent did not recognize any warning signs of stroke. Only 34.6% of subjects answered the correct nationwide emergency telephone number in Brazil (# 192). Only 51.4% of subjects would call emergency medical services for a relative with symptoms of stroke. In a multivariate analysis, individuals with higher education called emergency medical services (P=0.038, OR=1.5, 95%, CI: 1.02 to 2.2) and knew at least one risk factor for stroke (P<0.05, OR=2.0, 95% CI: 1.2 to 3.2) more often than those with lower education. Conclusions-Our study discloses alarming lack of knowledge about activation of emergency medical services and availability of acute stroke treatment in Brazil. These findings have implications for public health initiatives in the treatment of stroke and other cardiovascular emergencies.

Focal and linear endocardial and epicardial catheter-based cryoablation of normal and infarcted ventricular tissue

Background: This study of a chronic porcine postinfarction model examined whether linear epicardial cryoablation was capable of creating large, homogenous lesions in regions of the myocardium including scarred ventricle. Endocardial and epicardial focal cryolesions were also compared to determine if there were significant differences in lesion characteristics. Methods: Eighty focal endocardial and 28 focal epicardial cryoapplications were delivered to eight normal caprine and four normal porcine ventricular myocardium, and 21 linear cryolesions were applied along the border of infarcted epicardial tissue in a chronic porcine infarct model in six swines. Results: Focal endocardial cryolesions in normal animals measured 9.7 +/- 0.4 mm (length) by 7.3 +/- 1.4 mm (width) by 4.8 +/- 0.2 mm (depth), while epicardial lesions measured 10.2 +/- 1.4 mm (length) by 7.7 +/- 2 mm (width) by 4.6 +/- 0.9 mm (depth); P > 0.05. Linear epicardial cryolesions in the chronic porcine infarct model measured 36.5 +/- 7.8 mm (length) by 8.2 +/- 1.3 mm (width) by 6.0 +/- 1.2 mm (depth). The mean depth of linear cryolesions applied to the border of the infarct scar was 7 +/- 0.7 mm, as measured by magnetic resonance imaging. Conclusions:Cryoablation can create deep lesions when delivered to the ventricular epicardium. Endocardial and epicardial cryolesions created by a focal cryoablation catheter are similar in size and depth. The ability to rapidly create deep linear cryolesions may prove to be beneficial in substrate-based catheter ablation of ventricular arrhythmias.

Comparative analysis of rabies virus isolates from Brazilian canids and bats based on the G gene and G-L intergenic region

Rabies virus (RABV) isolates from two species of canids and three species of bats were analyzed by comparing the C-terminal region of the G gene and the G-L intergenic region of the virus genome. Intercluster identities for the genetic sequences of the isolates showed both regions to be poorly conserved. Phylogenetic trees were generated by the neighbor-joining and maximum parsimony methods, and the results were found to agree between the two methods for both regions. Putative amino acid sequences obtained from the G gene were also analyzed, and genetic markers were identified. Our results suggest that different genetic lineages of RABV are adapted to different animal species in Brazil.

Tooth Tissue Engineering: Optimal Dental Stem Cell Harvest Based on Tooth Development

Our long-term objective is to devise reliable methods to generate biological replacement teeth exhibiting the physical properties and functions of naturally formed human teeth. Previously, we demonstrated the successful use of tissue engineering approaches to generate small, bioengineered tooth crowns from harvested pig and rat postnatal dental stem cells (DSCs). To facilitate characterizations of human DSCs, we have developed a novel radiographic staging system to accurately correlate human third molar tooth developmental stage with anticipated harvested DSC yield. Our results demonstrated that DSC yields were higher in less developed teeth (Stages 1 and 2), and lower in more developed teeth (Stages 3, 4, and 5). The greatest cell yields and colony-forming units (CFUs) capability was obtained from Stages 1 and 2 tooth dental pulp. We conclude that radiographic developmental staging can be used to accurately assess the utility of harvested human teeth for future dental tissue engineering applications.

Oral squamous cell carcinoma: status of tight junction claudins in the different histopathological patterns and relationship with clinical parameters. A tissue-microarray-based study of 136 cases

Aims Claudins are integral transmembrane proteins of the tight junctions, critical for maintaining cell adhesion and polarity. Alterations in the expression of individual claudins have been detected in carcinomas and appear to correlate with tumour progression. Methods In this study, a panel of anti-claudin antibodies (anti-claudins 1, 2, 3, 4, 5 and 7) was employed to map claudin expression in 136 cases of oral squamous cell carcinoma (OSCC) organised in a tissue microarray. Results Claudins were expressed in a reticular pattern up to the prickle layer in normal mucosal epithelium. In OSCC, claudins were strongly present in well-differentiated tumours, they presented mild and low expression in moderately differentiated OSCC, and were negative in poorly differentiated OSCC; the absences of claudin 1 (p = 0.002) and claudin 4 (p<0.001) were associated with moderately/poorly differentiated tumours. Strong expression of claudin 4 was associated with decreased perineural infiltration (p = 0.024). Claudins 5 and 7 were mostly negative or weakly expressed in all cases studied. Expression of claudin 7 was associated with the early clinical stages of the disease, whereas loss of claudin 7 tended to be more frequent in advanced stages of OSCC (p = 0.054). Absence of claudin 7 was also associated with absent vascular infiltration (p = 0.045) and with presence of recurrence (p = 0.052). Conclusions Claudin expression patterns showed a strong correlation with histological type of OSCC; claudin expression was decreased in areas of invasion, and negative in poorly differentiated tumours. This pattern may be related to evolution and prognosis of these tumours, especially in the case of claudin 7, which seems to be associated with a poor prognosis in OSCC.