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Browsing NCIR - Artigos by Author "Barbosa, MD"
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- Amplified and Homozygously Deleted Genes in Glioblastoma: Impact on Gene Expression LevelsPublication . Crespo, I; Tão, H; Nieto, AB; Rebelo, O; Domingos, P; Vital, AL; Patino, MC; Barbosa, MD; Lopes, MC; Resende de Oliveira, C; Orfão, A; Tabernero, MDBACKGROUND: Glioblastoma multiforme (GBM) displays multiple amplicons and homozygous deletions that involve relevant pathogenic genes and other genes whose role remains unknown. METHODOLOGY: Single-nucleotide polymorphism (SNP)-arrays were used to determine the frequency of recurrent amplicons and homozygous deletions in GBM (n = 46), and to evaluate the impact of copy number alterations (CNA) on mRNA levels of the genes involved. PRINCIPAL FINDINGS: Recurrent amplicons were detected for chromosomes 7 (50%), 12 (22%), 1 (11%), 4 (9%), 11 (4%), and 17 (4%), whereas homozygous deletions involved chromosomes 9p21 (52%) and 10q (22%). Most genes that displayed a high correlation between DNA CNA and mRNA levels were coded in the amplified chromosomes. For some amplicons the impact of DNA CNA on mRNA expression was restricted to a single gene (e.g., EGFR at 7p11.2), while for others it involved multiple genes (e.g., 11 and 5 genes at 12q14.1-q15 and 4q12, respectively). Despite homozygous del(9p21) and del(10q23.31) included multiple genes, association between these DNA CNA and RNA expression was restricted to the MTAP gene. CONCLUSIONS: Overall, our results showed a high frequency of amplicons and homozygous deletions in GBM with variable impact on the expression of the genes involved, and they contributed to the identification of other potentially relevant genes.
- Choroid plexus tumours: a surgically treated seriesPublication . Barbosa, MD; Rebelo, O; Barbosa, P; Lacerda, A; Fernandes, RChoroid plexus tumours-carcinomas and papillomas are rare, especially in adults, and they pose some problems in their diagnosis and management. We have reviewed a series of nine cases from our institution surgically treated during the last 18 years. Their clinical charts, neuroradiological examinations, surgical technique, neuropathology and follow-up were analysed. In only one case total removal proved to be impossible, but even in cases of total removal recurrence appeared in two cases (one carcinoma and one papilloma). Morbility is especially associated with posterior fossa tumours. These rare tumours are managed surgically. They are usually associated with hydrocephalus, and it is difficult to forecast whether or not permanent CSF drainage will be required. A long-term follow-up is needed in patients with this type of tumour.
- Craniectomia descompressiva na enfarte cerebral malignoPublication . Cabrita, F; Pereira, R; Carvalho, M; Cordeiro, G; Barbosa, MD
- Cystic intraventricular schwannoma: case report and review of the literaturePublication . Barbosa, MD; Rebelo, O; Barbosa, P; Gonçalves, J; Fernandes, RIntraventricular schwannoma is an exceedingly rare tumour with only 6 cases described in the literature. One case of a cystic intraventricular schwannoma operated on at our Institution is analyzed and the other cases reported in the literature are reviewed. Complete removal was achieved and no recurrence was noted after a follow-up period of 10 years. Intraventricular schwannomas are rare tumours that are amenable to complete surgical removal, having a good prognosis without the need of adjuvant therapy.
- Epilepsia pós-traumática: Conceitos médico-legaisPublication . Barbosa, MD; Costa, G
- Hemorragia Subaracnoideia e Angiografia Cerebral por Tomografia ComputorizadaPublication . Santos, N; Machado, E; Carvalho, S; Barbosa, MD; Martins, FWe present a review of 57 cases of nontraumatic subarachnoid hemorrhagesubmitted to CT angiography of the cerebral vessels. The purpose of our study was to estimate the value of CT angiography in the detection of intracranial aneurysms. These findings were compared with those from selective angiography. The results showed that CT angiography is a rapid, low-risk technique with a low level of invasiveness and high specificity and sensitivity in the detection of cerebral aneurysms, allowing the planning of endovascular intervention and surgical approach.
- Intramedullary cervical cavernous angiomaPublication . Barbosa, MD; Fernandes, R; Seabra-Santos, H
- Intraventricular LesionPublication . Bastos-Lima, P; Marques, C; Cabrita, F; Barbosa, MD; Rebelo, O; Rio, F
- Intraventricular neurocytoma: a clinical and pathological study of three cases and review of the literaturePublication . Barbosa, MD; Balsitis, M; Jaspan, T; Lowe, JThree patients with a recently described tumor of neuronal origin, intraventricular neurocytoma, are presented. These tumors occur as intraventricular lesions in young patients, and the prognosis after surgical treatment is favorable. The initial pathological diagnosis of intraventricular neurocytoma may be difficult because of the striking resemblance of these tumors to oligodendroglioma and, to a lesser extent, ependymoma on light microscopic examination. Despite the use of wide-ranging panels of monoclonal antibodies, previous authors have not found any characteristic immunohistochemical staining patterns, but in our three patients, the use of synaptophysin, glial fibrillary acidic protein, and Leu-7 demonstrated staining patterns that may be useful in the diagnosis of this tumor. The monoclonal antibody Ki-67 was used to stain one tumor and showed a low cell proliferation rate. We have reviewed the clinical, radiological, and pathological features of these 3 patients and 17 previously described patients in an attempt to determine the important diagnostic features of intraventricular neurocytoma. Intraventricular neurocytoma should be considered in any young patient with symptoms of raised intracranial pressure and radiological evidence of an intraventricular lesion. Pathological diagnosis requires the use of electron microscopy to show features of neuronal differentiation; however, immunohistochemical demonstration of a neuronal phenotype is also a useful adjunct to diagnosis. Failure to use specialized techniques for pathological diagnosis will lead to misdiagnosis of these lesions as oligodendrogliomas, as was the initial diagnosis in 2 of our patients before review.
- The novel 5-lipoxygenase inhibitor ABT-761 attenuates cerebral vasospasm in a rabbit model of subarachnoid hemorrhagePublication . Barbosa, MD; Arthur, AS; Louis, RH; MacDonald, T; Polin, RS; Gazak, C; Kassell, NFOBJECTIVE: Eicosanoids have been implicated in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). Leukotrienes, 5-hydroxyperoxyeicosatetraenoic acid, and 5-hydroxyeicosatetraenoic acid are part of this group of substances, resulting from the 5-lipoxygenase activity on arachidonic acid metabolism. This study examined the effects of ABT-761, a new 5-lipoxygenase inhibitor, on cerebral vasospasm in an in vivo rabbit model of SAH. METHODS: A total of 48 rabbits were assigned to one of six groups: SAH + placebo (n = 8), SAH + ABT-761 20 mg/kg (n = 8), SAH + ABT-761 30 mg/kg (n = 8), control + placebo (n = 8), control + ABT-761 20 mg/kg (n = 8), and control + ABT-761 30 mg/kg (n = 8). Drug administration was initiated 30 minutes after induction of SAH and repeated 24 hours later. The animals were killed 48 hours after SAH, using the perfusion-fixation method. The cross sectional areas of basilar artery histological sections were measured by an investigator blinded to the treatment groups of the individual samples. RESULTS: In placebo-treated animals, the average luminal cross sectional area of the basilar artery was reduced by 68% after SAH as compared with controls (P < 0.0001). After SAH, the vasospastic response was attenuated in animals treated with 20 or 30 mg/kg representing a 28 or 35% reduction, respectively (P = 0.0011 and P = 0.0038). CONCLUSION: The results demonstrated that ABT-761 is effective in attenuating experimental cerebral vasospasm, indicating that this new drug represents a potential therapeutic agent for the treatment of vasospasm after SAH.