Comparison between the C5 or C6-Cz electrode assembly and C3 or C4-Cz assembly for transcranial electric motor activation of muscular response of the contralateral facial nerve

We used an assembly of electrodes C3 and C4-Cz in order to activate the motor cortical area of the corticobulbar tract to elucidate the motor-evoked potential of the contralateral mentalis muscle. We compared this setup to that of an assembly with electrodes C5 or C6-Cz using a train of electrical pulses and a single electrical pulse. This analysis was made in 23 consecutive patients who underwent several varied surgeries and were prospectively operated on at Santa Paula Hospital between January and June 2011. The results showed that the assembly with C5 or C6-Cz produced a multisynaptic motor-evoked potential in the contralateral mentalis muscle in 86.9 % of the patients, whereas 82.6 % of patients stimulated at points C3 or C4-Cz presented the same response. However, both assemblies showed similar behavior with the use of a single electrical pulse for peripheral contralateral nerve stimulation. We concluded that the C5 or C6-Cz assembly was similar to C3 or C4-Cz in obtaining a multisynaptic response in the contralateral mentalis muscle, although it required less intensive stimulation than the C3 or C4- Cz assembly.

Glycosaminoglycans modulate C6 glioma cell adhesion to extracellular matrix components and alter cell proliferation and cell migration

Abstract Background Adhesion to extracellular matrix (ECM) components has been implicated in the proliferative and invasive properties of tumor cells. We investigated the ability of C6 glioma cells to attach to ECM components in vitro and described the regulatory role of glycosaminoglycans (GAGs) on their adhesion to the substrate, proliferation and migration. Results ECM proteins (type IV collagen, laminin and fibronectin) stimulate rat C6 glioma cell line adhesion in vitro, in a dose-dependent manner. The higher adhesion values were achieved with type IV collagen. Exogenous heparin or chondroitin sulfate impaired, in a dose-dependent manner the attachment of C6 glioma cell line to laminin and fibronectin, but not to type IV collagen. Dextran sulfate did not affect C6 adhesion to any ECM protein analyzed, indicating a specific role of GAGs in mediating glioma adhesion to laminin and fibronectin. GAGs and dextran sulfate did not induce C6 glioma detachment from any tested substrate suggesting specific effect in the initial step of cell adhesion. Furthermore, heparin and chondroitin sulfate impaired C6 cells proliferation on fibronectin, but not on type IV collagen or laminin. In contrast, both GAGs stimulate the glioma migration on laminin without effect on type IV collagen or fibronectin. Conclusion The results suggest that GAGs and proteoglycans regulate glioma cell adhesion to ECM proteins in specific manner leading to cell proliferation or cell migration, according to the ECM composition, thus modulating tumor cell properties.

Enhancement of blood-tumor barrier permeability by Sar-[D-Phe8]des-Arg9BK, a metabolically resistant bradykinin B1 agonist, in a rat C6 glioma model

Abstract Background While it is well known that bradykinin B2 agonists increase plasma protein extravasation (PPE) in brain tumors, the bradykinin B1 agonists tested thus far are unable to produce this effect. Here we examine the effect of the selective B1 agonist bradykinin (BK) Sar-[D-Phe8]des-Arg9BK (SAR), a compound resistant to enzymatic degradation with prolonged activity on PPE in the blood circulation in the C6 rat glioma model. Results SAR administration significantly enhanced PPE in C6 rat brain glioma compared to saline or BK (p < 0.01). Pre-administration of the bradykinin B1 antagonist [Leu8]-des-Arg (100 nmol/Kg) blocked the SAR-induced PPE in the tumor area. Conclusions Our data suggest that the B1 receptor modulates PPE in the blood tumor barrier of C6 glioma. A possible role for the use of SAR in the chemotherapy of gliomas deserves further study.

Retroviral transfer of the p16INK4a cDNA inhibits C6 glioma formation in Wistar rats

Abstract Background The p16INK4A gene product halts cell proliferation by preventing phosphorylation of the Rb protein. The p16INK4a gene is often deleted in human glioblastoma multiforme, contributing to unchecked Rb phosphorylation and rapid cell division. We show here that transduction of the human p16INK4a cDNA using the pCL retroviral system is an efficient means of stopping the proliferation of the rat-derrived glioma cell line, C6, both in tissue culture and in an animal model. C6 cells were transduced with pCL retrovirus encoding the p16INK4a, p53, or Rb genes. These cells were analyzed by a colony formation assay. Expression of p16INK4a was confirmed by immunohistochemistry and Western blot analysis. The altered morphology of the p16-expressing cells was further characterized by the senescence-associated β-galactosidase assay. C6 cells infected ex vivo were implanted by stereotaxic injection in order to assess tumor formation. Results The p16INK4a gene arrested C6 cells more efficiently than either p53 or Rb. Continued studies with the p16INK4a gene revealed that a large portion of infected cells expressed the p16INK4a protein and the morphology of these cells was altered. The enlarged, flat, and bi-polar shape indicated a senescence-like state, confirmed by the senescence-associated β-galactosidase assay. The animal model revealed that cells infected with the pCLp16 virus did not form tumors. Conclusion Our results show that retrovirus mediated transfer of p16INK4a halts glioma formation in a rat model. These results corroborate the idea that retrovirus-mediated transfer of the p16INK4a gene may be an effective means to arrest human glioma and glioblastoma.

Monitoramento por imagem de ressonância magnética do crescimento tumoral no modelo C6 de glioblastoma com perspectivas de avaliação da terapia de magnetohipertemia

Objetivo: Estabelecer um padrão de crescimento tumoral (volume) em ratos Wistar submetidos ao modelo C6 de glioblastoma multiforme por meio de imagens de ressonância magnética para posterior verificação de redução de volume tumoral com a terapia de magnetohipertermia. Métodos: Para o modelo C6, utilizamos ratos Wistar, machos, jovens, pesando entre 250 e 300 g. Após anestesiados (cetamina 55 mg/kg e xilazina 11 mg/kg) foram injetadas estereotaxicamente células tumorigênicas linhagem C6 suspensas em meio de cultura (105 células em 10 µL) no córtex frontal direito (coordenadas a partir do bregma: anteroposterior = 2,0 mm; látero-lateral = 3,0 mm; profundidade = 2,5 mm) com uma seringa Hamilton. No Grupo Controle, houve a injeção do meio de cultura sem as células. Posteriormente, foram feitas imagens mediante a técnica de imagem por ressonância magnética em 14, 21 e 28 dias após a injeção em um escâner de imagem por ressonância magnética 2.0 T (Bruker BioSpec, Germany). Para o exame, os animais foram anestesiados com cetamina 55 mg/kg e xilazina 11 mg/kg. Multifatias coronais foram adquiridas utilizando uma sequência spin-echo padrão com os seguintes parâmetros: TR/TE = 4,000 ms/67,1 ms, FOV = 3,50, Matrix 192, slice thickness = 0,4 mm e slice separation = 0 mm. Resultados: A análise das imagens de ressonância magnética do tumor possibilitou a clara visualização da massa tumoral, sendo possível ainda estabelecer parâmetros de volume tumoral nos diferentes dias analisados. O volume de 14 dias após a indução do foi de 13,7 ± 2,5 mm3 . Aos 21 dias, o volume alcançado foi de 31,7 ± 6,5 mm3 e, aos 28 dias, a massa tumoral atingiu 122,1 ± 11,8 mm3 . Conclusão: Estes resultados mostraram a possiblidade de avaliação do volume tumoral no modelo C6 em ratos, o que possibilitará, no futuro, a aplicação da terapia de magnetohipertermia bem como verificação de seus resultados.

Monitoramento in vivo por imagem por ressonância magnética de células C6 de glioma marcadas com nanopartículas superparamagnéticas de óxido de ferro

OBJECTIVE: The aim of the current study was to monitor the migration of superparamagnetic iron oxide nanoparticle (SPION)-labeled C6 cells, which were used to induce glioblastoma tumor growth in an animal model, over time using magnetic resonance imaging (MRI), with the goal of aiding in tumor prognosis and therapy. METHODS: Two groups of male Wistar rats were used for the tumor induction model. In the first group (n=3), the tumors were induced via the injection of SPION-labeled C6 cells. In the second group (n=3), the tumors were induced via the injection of unlabeled C6 cells. Prussian Blue staining was performed to analyze the SPION distribution within the C6 cells in vitro. Tumor-inducing C6 cells were injected into the right frontal cortex, and subsequent tumor monitoring and SPION detection were performed using T2- and T2*-weighted MRI at a 2T field strength. In addition, cancerous tissue was histologically analyzed after performing the MRI studies. RESULTS: The in vitro qualitative evaluation demonstrated adequate distribution and satisfactory cell labeling of the SPIONs. At 14 or 21 days after C6 injection, a SPION-induced T2- and T2*-weighted MRI signal reduction was observed within the lesion located in the left frontal lobe on parasagittal topography. Moreover, histological staining of the tumor tissue with Prussian Blue revealed a broad distribution of SPIONs within the C6 cells. CONCLUSION: MRI analyses exhibit potential for monitoring the tumor growth of C6 cells efficiently labeled with SPIONs.

First Identification of Culex flavivirus (Flaviviridae) in Brazil

Introduction: Culex flavivirus (CxFV) was first isolated in 2007 from Culex pipiens in Japan and then identified in several other countries. Characterization of the CxFV showed that all strains are related to the cell fusing agent virus. In this manuscript we report the first identification of CxFV in South America. Material and Methods: We have collected Culex sp. mosquitoes using BG-Sentinel traps and manual aspirators. They were pooled according to genus, species, sex and location. Viral RNA was extracted and multiplex nested PCR was performed to test the presence of Flavivirus. The positive samples were isolated in C6/36 cells and sequenced for phylogenetic analyses. Results: 265 female Culex mosquitoes pooled in 83 pools were tested with specific CxFV, Saint Louis encephalitis virus (SLEV) and West Nile virus (WNV) primers. Our sequence data indicated maximum sequence similarity of 97% with CxFV. Discussion: In this study we report the circulation of CxFV in an urban setting where SLEV had previously caused an outbreak. In terms of public health, this is an important finding due to the assumption that the previous exposition of mosquitoes to CxFV might lessen the susceptibility of these mosquitoes to other flaviviruses. Copyright (C) 2012 S. Karger AG, Basel

Prognostic value of thumb pain sensation in birth brachial plexopathy

Objective: To evaluate the prognostic value of absent thumb pain sensation in newborns and young infants with birth brachial plexopathy. Methods: We evaluated 131 patients with birth brachial plexopathy with less than two months of age. Pain sensation was evoked by thumb nail bed compression to evaluate sensory fibers of the upper trunk (C6). The patients were followed-up monthly. Patients with less than antigravity elbow flexion at six months of age were considered to have a poor outcome. Results: Thirty patients had absent thumb pain sensation, from which 26 showed a poor outcome. Sensitivity of the test was 65% and specificity was 96%. Conclusion: Evaluation of thumb pain sensation should be included in the clinical assessment of infants with birth brachial plexopathy.

RESULTS OF ULNAR NERVE NEUROTIZATION TO BICEPS BRACHII MUSCLE IN BRACHIAL PLEXUS INJURY

Objective: To evaluate the factors influencing the results of ulnar nerve neurotization at the motor branch of the brachii biceps muscle, aiming at the restoration of elbow flexion in patients with brachial plexus injury. Methods: 19 patients, with 18 men and 1 woman, mean age 28.7 years. Eight patients had injury to roots C5-C6 and 11, to roots C5-C6-C7. The average time interval between injury and surgery was 7.5 months. Four patients had cervical fractures associated with brachial plexus injury. The postoperative follow-up was 15.7 months. Results: Eight patients recovered elbow flexion strength MRC grade 4; two, MRC grade 3 and nine, MRC <3. There was no impairment of the previous ulnar nerve function. Conclusion: The surgical results of ulnar nerve neurotization at the motor branch of brachii biceps muscle are dependent on the interval between brachial plexus injury and surgical treatment, the presence of associated fractures of the cervical spine and occipital condyle, residual function of the C8-T1 roots after the injury and the involvement of the C7 root. Signs of reinnervation manifested up to 3 months after surgery showed better results in the long term. Level of Evidence: IV, Case Series.

Upper Brachial Plexus Injuries: Grafts vs Ulnar Fascicle Transfer to Restore Biceps Muscle Function

BACKGROUND: Nerve transfers or graft repairs in upper brachial plexus palsies are 2 available options for elbow flexion recovery. OBJECTIVE: To assess outcomes of biceps muscle strength when treated either by grafts or nerve transfer. METHODS: A standard supraclavicular approach was performed in all patients. When roots were available, grafts were used directed to proximal targets. Otherwise, a distal ulnar nerve fascicle was transferred to the biceps branch. Elbow flexion strength was measured with a dynamometer, and an index comparing the healthy arm and the operated-on side was developed. Statistical analysis to compare both techniques was performed. RESULTS: Thirty-five patients (34 men) were included in this series. Mean age was 28.7 years (standard deviation, 8.7). Twenty-two patients (62.8%) presented with a C5-C6 injury, whereas 13 patients (37.2%) had a C5-C6-C7 lesion. Seventeen patients received reconstruction with grafts, and 18 patients were treated with a nerve transfer from the ulnar nerve to the biceps. The trauma to surgery interval (mean, 7.6 months in both groups), strength in the healthy arm, and follow-up duration were not statistically different. On the British Medical Research Council muscle strength scale, 8 of 17 (47%) patients with a graft achieved >= M3 biceps flexion postoperatively, vs 16 of 18 (88%) post nerve transfers (P = .024). This difference persisted when a muscle strength index assessing improvement relative to the healthy limb was used (P = .031). CONCLUSION: The results obtained from ulnar nerve fascicle transfer to the biceps branch were superior to those achieved through reconstruction with grafts.

Cu(GlyGlyHis) effects on MCF7 cells: Copper uptake, reactive oxygen species generation and membrane topography changes

Elevated levels of copper have been detected in various types of human cancer cells, such as breast cancer cells, and a number of mechanisms have been proposed to explain the action and influence of copper on tumor progress. In this work, we found that stimulating the proliferation of mammary epithelial MCF7 cells with the high-redox-potential copper complex Cu (GlyGlyHis) is associated with the copper-induced intracellular generation of reactive oxygen species (ROS) that induces lipid peroxidation and causes increased roughness of external cell membranes, which leads to the formation of larger cell domes. The results presented herein provide new insights into the molecular link between copper and the proliferation of breast cancer cells and, consequently, into the mechanism by which changes in redox balance and ROS accumulation regulates cell membrane roughness. (C) 2012 Elsevier Inc. All rights reserved.

Self-Assembly of Poly(4-vynil-N-alkylpyridinium) Bromide onto Silica: Effect of Side-Chain Length on Structural Aspects at a Molecular Level

Self-assembly of poly(4-vynil-N-alkyl)pyridinium bromide with alkyl side chains of 2, 5, 7, 10, or 16 carbons from ethanolic solutions onto flat silica surfaces was studied by means of ellipsometry, atomic force microscopy (AFM), contact angle measurements, and sum-frequency generation (SFG) vibrational spectroscopy in the CH3 and CH2 stretch region. Ab initio quantum-chemical calculations on the N-alkylpyridinium side-group with restricted Hartree-Fock (RHF) method and 6-311G (d,p) basis set were C one to estimate the charge distribution along the pyridinium ring and the alkyl side-chain. SFG results showed that longer side chains promote the disorientation of the alkyl groups at the surface, corroborating with the contact angle values. AFM images revealed film homogeneity, regardless the alkyl side group. However, after 24 h contact with water, ringlike structures appeared on the film surfaces, when the polycation alkyl side chain had 7 or less carbons, and as the alkyl chain increased to 10 or 16 carbons, the films dewetted because the hydrophobic interactions prevailed over the electrostatic interactions between the pyridinium charged groups and the negatively charged SiO2 surface. Under acid conditions (HCl 0.1 mol.L-1), the film mean thickness values decreased up to 50% of original values when the alkyl side chains were ethyl or pentyl groups due to ion-pair disruption, but for longer groups they remained unchanged. Quantum-chemical optimization and Mulliken electron population showed that (i) from C2 to C15 the positive charge at the headgroup (HG) decreased 0.025, while the charge at combined HG + alpha-CH2 increased 0.037; and (ii) for C6 or longer, the alkyl side group presents a tilt in the geometry, moving away from the plane. Such effects summed up over the whole polymer chain give support to suggest that when the side chains are longer than 7 carbons, the hydrophobic interaction decreases film stability and increases acid resistance.

Resultado da neurotização do nervo ulnar para o músculo bíceps braquial na lesão do plexo braquial

OBJETIVO: Avaliar de forma crítica os fatores que influenciam os resultados da neurotização do nervo ulnar no ramo motor do músculo bíceps braquial, visando a restauração da flexão do cotovelo em pacientes com lesão do plexo braquial. MÉTODOS: 19 pacientes, 18 homens e uma mulher, com idade média de 28,7 anos foram avaliados entre fevereiro de 2003 e maio de 2007. Oito pacientes apresentavam lesão das raízes C5-C6 e 11, das raízes C5-C6-C7. O intervalo de tempo médio entre a injúria e o tratamento cirúrgico foi 7,5 meses. Quatro pacientes apresentavam fraturas cervicais associadas à lesão do plexo braquial. O seguimento pós-operatório foi de 15,7 meses. RESULTADO: Oito pacientes recuperaram força de flexão do cotovelo MRC grau 4; dois, MRC grau 3 e nove, MRC < 3. Não houve prejuízo da função prévia do nervo ulnar. CONCLUSÃO: Os resultados da cirurgia de neurotização do nervo ulnar no ramo motor no músculo bíceps braquial são dependentes: do intervalo decorrido entre a lesão do plexo e o tratamento cirúrgico, da presença de fraturas associadas da coluna cervical e côndilo occipital, da função residual das raízes de C8-T1 após o trauma e do acometimento da raiz de C7. Sinais de reinervação manifestados até 3 meses no pós cirúrgico mostram melhores resultados ao longo prazo. Nível de Evidência: IV, Série de Casos.