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Biomedical subjects

J Xavier

Publications and source records attributed to J Xavier.

10 recordsLinked to original sources

Mesencephalo-diencephalic angioanatomy in arteriovenous malformations. Endovascular management of transmesencephalic vs subependymal supply in 954 cases between 1982 and 1994.

This report presents the arteries of the mesencephalo-diencephalic region and their different role in the supply to the cerebral structures. Among them, the authors distinguish the subependymal and transmesencephalic arteries to which they pay a special attention since these vessels present a specific angiographic aspect. The importance of their differentiation is emphasized. The authors discuss the management of subependymal and (trans)mesencephalic arteries during endovascular neuro-intervention illustrative cases.

Cerebral Angiography↗

[The status of hemoglobin concentration and hematocrit in Angola children].

Hemoglobin-concentration (Hb) and hematocrit (Ht) were determined in 622 Angolean children between ages of 3 months and 13 years. The children were divided into two groups: group I (n = 530) of low social and economic state, group II (n = 92) children enjoyed good living conditions. 38.9% of all children had a Hb below 6.8mmol/l. 218 of which were part of group I, only 18 were out of group II. An extensive anemia (less than Hb 4.3mmol/l) existed in only 3% of all children. 51.7% of children were below 3 years. Between age groups of 3 months to over 10 years there was a continual rise in Hb of 17.6 +/- 6.6% (boys) and 9.5 +/- 3% (girls). Using the Ht values the percentage of anemic children was only 16.4%. It existed a relationship, especially, clearly observed in group I, between physical development and aemia frequency. Children of group I were more anemic than children of group II.

Anemia↗

[Dysembryoplastic neuroepithelial tumors].

INTRODUCTION: The dysembryoplastic neuroepithelial tumors tend to occur in young patients, with partial complex partial seizures which is refractory to medical treatment. These are stable lesions, with defined histological features, specially with clinical data corroboration. CLINICAL CASES: The clinical, imagiological, operative, and histopathological data of six patients with proved dysembryoplastic neuroepithelial tumors were reviewed. All patients had seizures with age at onset ranged from 7 to 27 years. Five lesions were located in the temporal lobe and one in the parietal lobe. Common features included cortical to subcortical location, low density in CT-scan, very low signal intensity on T1-weighted images and high signal on T2-weighted images. Calcification occurred in two lesions, and three showed contrast enhancement. Complete resection of the tumor was performed in three cases, and subtotal resection in other three cases. Pathological features included oligodendroglial-like cells, glioneural component, and few cases showed dysplastic cortical disorganization. The postoperative period of follow-up ranged from 2 to 18 months. Four patients were seizure free, two of which had subtotal resection of the lesion. The remaining two patients maintained seizures. CONCLUSIONS: The clinical, imagiological and histopathological data of the six cases presented are generally compatible with those of the reports reviewed by the authors. The imagiological features are nonspecific. Surgical treatment permits histological diagnosis and epilepsy control.

Adolescent↗

[Isolation of Mycoplasma bovis during an outbreak of bovine mastitis at a dairy farm in the province of Buenos Aires. 1st report in the Republic of Argentina].

Several mycoplasma species produce various diseases in different animal species. M. bovis has been described as the cause of mastitis, arthritis, pneumonia and infertility in cattle. Furthermore, this species has been the most frequently isolated agent producing bovine mastitis. The objective of this study was to isolate and typify mycoplasma strains from a clinical mastitis outbreak in a dairy farm of Buenos Aires Province. A total of 279 samples were studied (276 from pooled quarter milk of cows with clinical mastitis that did not respond to antibiotic therapy, 1 from bulk tank milk and 2 preputial swabs from bulls). The isolated mycoplasma strains (n = 12) were further characterized by biochemical analysis, serological studies and electrophoretic analysis of the protein profiles (SDS-PAGE). Based upon these studies, the isolated strains were identified as Mycoplasma bovis. This is the first report of isolation of this microorganism in Argentina. Therefore the results described here could be very useful to improve mastitis control in dairy farms.

Animals↗

[Vascularization of the skull base--review of the literature and illustrative cases].

The dural vascularization of the skull base and proximal nervous structures, depends on the external carotid artery, internal carotid artery and vertebral artery branches. The authors describe these branches, emphasizing possible anastomoses between them, and present images from their own experience. Such arterio-arterial anastomosis represent incomplete regressions of embryologic arterial connections and are always present, but functionally inactive. It is usually in the presence of pathologic situations (stroke, tumours, dural fistulas) that they become active and, therefore, special care is necessary if endovascular procedures with embolic material are to be performed.

Brain↗

[Endovascular treatment of dissecting aneurysms of the posterior cerebral artery].

In the literature, there are few reports of posterior cerebral artery aneurysms resulting from isolated dissections. In these cases the treatment is still a matter of discussion and includes anticoagulation, surgical intervention, endovascular techniques and conservative management. We present five cases of Posterior Cerebral Artery (PCA) aneurysms, with angiographic criteria of dissection (double lumen, proximal narrowing), all being situated at the P2 segment, three being close to the P1/P2 junction. In one case, a large aneurysm ruptured during the attempted catheterization with subsequent death of the patient. In three patients occlusion of the parent vessel was performed with Guglielmi detachable coils located proximal to the aneurysm, with no new neurological deficits. In the other case there was spontaneous thrombosis of the aneurysm. Occlusion of the parent vessel by endovascular techniques in dissecting PCA aneurysms has a low probability of neurological deficits and seems to be an appropriate approach for these aneurysms.

Adult↗

[Dural fistulas of the anterior cranial fossa].

Dural arterio-venous shunts (DAVS) of the anterior cranial fossa are quite rare. There are only a few cases reported in the literature. The authors present 5 cases of dural arterio-venous shunts (DAVS) of the anterior cranial fossa, allowing more data for later reviews of this rare and aggressive localisation of DAVS. The clinical set, imaging findings (with emphasis in diagnostic angiography), treatment and outcome in these 5 patients are described. Haemorrhage was the presenting form in 4 patients; the other case presented was investigated for headache. There were bilateral symmetric feeders in two patients, unilateral feeders in another two and unilateral predominant feeders in one; contribution of the external carotid artery, when present, was always minimal. Venous drainage included one or combinations of these: superior sagittal sinus, sylvian veins and cavernous sinus. Three patients had venous aneurysms in anterior cranial fossa; of these, two presented with haemorrhage, but the third one of them has been asymptomatic for 7 years. Three patients were treated by surgical exclusion of the shunt and became clinical and angiographicaly normal. According to the literature, our cases confirm the highly aggressive behaviour of these DAVS. Surgical treatment is an efficacious method of therapy and should be done as soon as possible. Embolization can be attempted but is technically difficult and eventually too expensive.

Adult↗

[Ischemic optic neuropathy following a dural arteriovenous fistula. Vascular steal phenomenon].

CASE REPORT: We report the case of a 46-year-old patient, with a dural arteriovenous fistula in the left cavernous sinus fed by dural branches of both carotid siphons, by recurrent branches of the left ophthalmic artery (LOA) and by dural branches of the left external carotid artery. Twenty-four hours after arterial embolisation with polyvinyl alcohol particles, the patient suffered visual loss in the left eye. All feeders were embolized except the recurrent branches of the LOA, which became hypertrophied. Fluorescein angiography of the retina was normal. Transocular Doppler ultrasound showed a turbulent, inverted, low resistance flow in the LOA distal part, and a high resistance anterograde flow in the left central artery of the retina, which accounted for an ischemic optic neuropathy. CONCLUSIONS: The ischemic optic neuropathy resulted from a vascular steal phenomenon. Hypertrophy of recurrent branches of the LOA, after embolization of the remaining feeders, contributed to a low resistance shunt between the LOA proximal part and the left cavernous sinus. This shunt caused the inversion of flow in the distal part of the artery and the subsequent decrease of retrobulbar blood supply.

Central Nervous System Vascular Malformations↗

[How our pediatric services work].

The results of a questionnaire sent by the College of Pediatrics of the Portuguese Doctors Association (Ordem dos Médicos) to the pediatric departments all over the country are presented. From the answers of fifty-one services, physical conditions, equipment, human resources, assistancial and scientific activities developed are characterized.

Child↗