Célia Silva

O trauma raquimedular

A medula espinhal dos mamiferos adultos nao permite a regeneracao de axonios. Por razoes ainda desconhecidas, as fibras neurais falham em cruzar o sitio da lesao, como se nao houvesse crescimento, desde a primeira tentativa. Quais mecanismos poderiam explicar a perda da capacidade de regeneracao? As cicatrizes formadas pelas celulas da glia seriam uma consequencia da falha na regeneracao ou a causa? Diversas linhas de evidencia sugerem que a regeneracao da medula espinhal seria impedida no sistema nervoso central pela acao de fatores locais no sitio da lesao, e que o sistema nervoso central nao-lesado e um meio permissivo para o crescimento axonal, na direcao de alvos especificos. Uma vez que os axonios sao induzidos adequadamente a cruzar a lesao com o auxilio de implantes, farmacos ou celulas indiferenciadas, as fibras em regeneracao podem encontrar a via especifica e estabelecer conexoes corretas. O que ainda nao se sabe e que combinacao de moleculas induz/inibe o potencial de regeneracao do tecido e que mecanismos permitem aos neuronios formarem conexoes especificas com os alvos com os quais sao programados a fazer.

Anti-dyskinetic effect of the neuronal nitric oxide synthase inhibitor is linked to decrease of FosB/deltaFosB expression.

Rodents with lesion of dopaminergic pathway when receiving repeated l-3,4-dihydroxiphenylalanine (l-DOPA) treatment develop abnormal involuntary movements called dyskinesia. We demonstrated that nitric oxide synthase (NOS) inhibitors mitigate l-DOPA-induced dyskinesia in rodents. The aim of the present study was to verify if the in vivo preferential neuronal NOS (nNOS) inhibitor 7-nitroindazole (7-NI) affect the expression of the transcription factor FosB/ΔFosB in the lesioned striatum, an indicator of neuronal activity associated with dyskinesia. Male Wistar rats with unilateral microinjection (medial forebrain bundle) of either the neurotoxin 6-hydroxidopamine (6-OHDA; n=4-6/group) or saline (sham; n=6/group) were provided with l-DOPA (30mg/kg plus benserazide 7.5mg/kg/day, oral gavage), once a day during 22 days. 6-OHDA-lesioned animals developed abnormal involuntary movements (AIMs) classified as axial, limb, orofacial and locomotive dyskinesia and presented FosB/ΔFosB increase in the dopamine-depleted striatum. Administration of 7-NI (30mg/kg, i.p.), 30min prior to l-DOPA reduced the severity of AIMs (≈65% for axial, limb and orofacial and 74% for locomotive AIMs scores), without interfering with the rotarod performance. Simultaneously, 7-NI attenuated the expression of FosB/ΔFosB in dopamine-depleted striatum (≈65% in medial and ≈54% in lateral striatum, bregma 0.48mm). FosB/ΔFosB expression in lateral striatum was correlated with l-DOPA-induced dyskinesia. The findings described here corroborate a new approach to the management of l-DOPA-therapy in Parkinsons disease (PD) treatment.

Procedimento de Lecompte para a correção de transposição das grandes artérias, associada à comunicação interventricular e obstrução de via de saída do ventrículo esquerdo

OBJECTIVE: To evaluate the Lecompte procedure used for the correction of transposition of the great arteries (TGA) associated with ventricular septal defect (VSD) and left ventricle outflow tract obstruction (LVOTO) and to present the intermediate and long-term results of the surgery. METHODS: Between February 1994 and July 2005, seven patients with ages between 2 and 8 years (median: 3.0) suffering from TGA, VSD and LVOTO underwent corrective surgery. In six cases, the Lecompte procedure was performed. This technique consists in right ventriculotomy, extensive resection of the conal septum and construction of a ventricular tunnel connecting the left ventricle to the aorta (LV-Ao). The remaining case presented with obstruction of a valvular prosthesis implanted between the right ventricle and the pulmonary artery (RV-PA) and RV failure. This case was converted to the Lecompte procedure. RESULTS: The cardiopulmonary bypass time varied from 105 to 194 minutes (Median: 130) and the aortic clamping time varied from 65 to 90 minutes (Median: 78). There was one death in the immediate post-operative period due to coagulopathy followed by RV failure. Six patients were released from hospital between the 5th to 30th postoperative days (Median: 11) and the follow up period was from 12 to 144 months (Median: 73.6). CONCLUSIONS: The Lecompte procedure presents the following advantages: 1. Surgical indication for infants, 2. Low morbidity and mortality rates, 3. Free from reoperation over the long term. 4. Possibility of conversion of the Rastelli procedure into the Lecompte procedure.

Operação de Blalock-Taussig modificada para o tratamento paliativo de cardiopatias congênitas com hipofluxo pulmonar

From January 1990 to November 1994, 72 patients with congenital heart defects and low pulmonary flow underwent modified Blalock-Taussig produce. There were 44 (61.1%) males and 28 (38.8%) females with ages ranging from 2 days to 11 years (average 9 months). Thirty eight (52,8%) patients had Tetralogy of Fallot; 7 (9,7%) had pulmonary atresia with intact ventricular septum (PA/IVS); 6 (8.4%), had transposition of the great arteries (TGA) with pulmonary stenosis (PS); 6 (8,4%) had tricuspid atresia (TA) with PS; 6 (8.4%) had double inlet of right ventricle (RV) or left ventricle (LV) and PS; 3 (4.2%) had corrected transposition of the great arteries (CTGA) with ventricular septal defects (VSD) and PS; 2 (2.7%) had double outlet of RV or LV and PS; 2 (2.7%) had atrio-ventricular canal defects (A-VC) and PS; 2 (2.7%) patients had right or left Isomerism and PS. The decision to surgical indication was based on: a) new borns with ductus dependent heart defects; b) lactents with important cianosis or hypoxia; c) infants with heart defects without possibilities of biventricular correction. The surgical technique employed was the Blalock-Taussig operation using 4 or 5 mm Polytetrafluoroethy (PTFE) prosthesis in 69 (94.5%) cases, umbilical vein in 3 (4.1%) cases and bovine thoracic artery in 1 (1.4%) case. Before the arteries were clamped 1 mg/kg of heparine was given without mobilization, with protamine, after the procedure. During the post-operative period, anticoagulants were not given. The prosthesis obstruction was the main cause of death and was related to artery anatomy: subclavian and pulmonary artery diameter and/or problems with the technique. The modified Blalock-Taussig operation showed itself to be a reliable palliative treatment to heart defects with low pulmonary flow