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Biomedical subjects

R Cruz

Publications and source records attributed to R Cruz.

68 records · Page 4Linked to original sources
PubMed1981

The mass spectra of 13C labelled methylene derivatives of steroids--IV.

The mass spectra of the 3-ethylene ketal of delta 5-pregnan[20-13C]methylene-3-one and 17 beta-acetoxyl[3-13C]methyleneandrost-1-ene have been examined. In both cases there are some fragments which show either relatively large retention or elimination of 13C label and these can be assigned to some fragmentation paths which generally follow those found for diterpenic and steroidal hydrocarbons, and are in good agreement with the empirical fragmentations rules in mass spectrometry.

Carbon Isotopes↗
PubMedDate not supplied

[Behavior characterization of a model of Huntington's disease in rats, induced by quinolinic acid].

INTRODUCTION: Huntington's disease (HD) is a progressive neurodegenerative disorder, characterized by severe degeneration of basal ganglia neurons. Behavioral symptoms of HD include abnormal, uncontrollable and constant choreiform movements, impaired cognitive function and emotional disturbance. OBJECTIVE: In order to explore the changes of cognitive and motor functions induced by quinolinate lesion we realized this experiment. MATERIALS AND METHODS: We studied the behavior of rats with unilateral quinolinate induced lesions of the medial striatum. Intact 3 months old male rats (n = 23) were trained in the Morris Water Maze during three consecutive days, eight trials/day (acquisition), and before surgery they were randomly assigned either to intact or lesion groups. Fifteen days after the lesion the rats were tested using retention test (one day/four trials, with the escape platform in the same position as in acquisition test), on the next three days the rats were tested in the transfer test (three days/eight trials-day, with the platform in the new position). The Paw reaching test and the asymmetrical rotational behavior test in respond to amphetamine were also tested in these rats. RESULTS: Lesioned animals exhibited deficient retrieval of stored memories of visuospatial skills and impaired transfer of learning. In relation with motor activity the lesioned rats showed a profound impairment in the skill of the left forelimb for reaching food compared with its right forelimb as well as with the forelimb abilities of intact rats. The lesioned animals showed significant rotational behavior induced by amphetamine agonist, ipsilateral to the lesioned striatum. CONCLUSIONS: These results are consistent with the notion that the striatal degeneration could sufficiently account for the cognitive abnormalities associated with HD, and with the key role played by basal ganglia in enabling voluntary and postural adjustment of the movements.

Animals↗
PubMedDate not supplied

[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↗
PubMedDate not supplied

[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↗
PubMedDate not supplied

[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↗
PubMedDate not supplied

[Glutathione in cognitive function and neurodegeneration].

OBJECTIVE: To review the main findings on the glutathione role in cognitive function and synaptic plasticity processes, as well as, its involvement in neurotrophic and neurodegenerative events in rodents. DEVELOPMENT: The tripeptide glutathione and its related enzymes participate in the maintenance of oxidant homeostasis in aerobic cells. Oxidative damage to neuronal components underlies the molecular basis of neurodegeneration and brain aging. Several biomolecules with redox dependent activity are involved in the neuronal plasticity events that have a role in learning and memory functions. The maintenance of normal glutathione level is important for acquisition, but not consolidation, of spatial memory. Glutathione unavailability induces failures in hippocampal synaptic plasticity mechanisms, which are possibly related to a spatial memory deficit. On the other hand, several studies have suggested that the beneficial effects of neurotrophic treatments are mediated by the modulation of antioxidant defense mechanisms. In fact, nerve growth factor treatment to cognitively impaired rats stimulates glutathione reductase and can prevent the increases in glutathione peroxidase activity, pointing these enzymes as possible intracellular targets of neurotrophin actions on oxidant homeostasis. CONCLUSION: There is a closed link between glutathione metabolism and oxidant homeostasis, which is expressed in learning and synaptic plasticity deficits in conditions of low glutathione content, as well as, in neurodegeneration induced glutathione metabolism changes that can be prevented by neurotrophic treatment

Aging↗