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Biomedical subjects

P Sardo

Publications and source records attributed to P Sardo.

29 records · Page 2Linked to original sources
PubMed1992

Accumbens-caudate-septal circuit as a system for hippocampal regulation: involvement of a GABAergic neurotransmission.

Hippocampal-based epileptiform activity may reach the basal ganglia via the nucleus accumbens. Previous data suggested that caudate nucleus is able to influence hippocampal epilepsy, probably sending a projection to the septum. In order to test the hypothesis of a retrograde activation of accumbens-caudate pathway in hippocampal regulation, we electrically stimulated both caudate nucleus and nucleus accumbens and studied modifications of hippocampal EEG in the feline focal epilepsy model. We also performed bilateral electrolytic lesion of nucleus accumbens and repeated caudate stimulation. Results showed that nucleus accumbens stimulation was ineffective in modifying hippocampal epilepsy; on the contrary, caudate stimulation caused a statistically significant decrease of hippocampal spike frequency and amplitude. On the other hand, in accumbens-lesioned animals caudate activation consistently reduced hippocampal epilepsy to a significant degree. As the caudate nucleus influences hippocampal activity and the septum may constitute a relay station of this functional relation, a possibility was tested concerning a GABAergic mediation. To this end, after a stable caudate-induced effect was reached, an intraseptal microinjection of picrotoxin (GABA receptor antagonist) was made and caudate stimulation repeated at the same parameters. Such a study showed that after intraseptal picrotoxin, caudate stimulation failed to elicit any type of modification of hippocampal activity. Experimental findings support the notion that the striatal modulation on hippocampus is mediated by an anterograde rather than a retrograde pathway, and underline the possibility of a GABAergic caudate-septal influence.

Animals↗
PubMed1991

Dopaminergic control of feline hippocampal epilepsy: a nigro hippocampal pathway.

Substantia nigra is a mesencephalic structure inserted along several circuits which appear to play a key role in epilepsy. In previous researches we postulated that substantia nigra pars compacta (SNpc) may be the site of a precise control of hippocampal epilepsy while substantia nigra pars reticulata (SNpr) may exert a modulation of both neocortical epilepsy and spreading of hyperactivity toward a motor target. In order to better understand mechanisms subserving nigral action in feline hippocampal epilepsy we electrically stimulated SNpc (dopaminergic), before and after sulpiride (dopamine receptor-antagonist) intravenous injection. Furthermore we compared hippocampal epileptiform activity prior to and after apomorphine (dopamine receptor-agonist) intrahippocampal injection as well as prior to and after SNpc electrolytic destruction. Results showed that SNpc is able to regulate hippocampal epilepsy. This effect is selectively antagonized by sulpiride while apomorphine exerts, synergically with SNpc stimulation, inhibitory effects. On the contrary SNpc lesions induces a significant enhancement of hippocampal epileptiform spikes. Experimental findings suggest that SNpc represents a strategic region for the control of hippocampal excitability and that this regulation appears to be dopaminergic in nature.

Animals↗
PubMed1988

[Diagnostic and therapeutic role of angiography in acute vascular insufficiency of the superior mesenteric artery].

Sixteen patients were studied with acute arterial ischemia of the superior mesenteric artery: 2 thrombosis, 8 embolisms, and 6 non-occlusive ischemias. Six patients had intra-arterial selective perfusion of papaverine. Angiographic patterns of acute arterial ischemia of the superior mesenteric artery are described. The technique of intra-arterial injection of papaverine (fast bolus followed, if needed, by slow perfusion) is also described. The diagnostic value of plain abdominal radiography and arteriography, and the therapeutical value of pharmacoangiography are discussed.

Aged↗
PubMedDate not supplied

Neuropsychology of selective attention and magnetic cortical stimulation.

Informed volunteers were asked to perform different neuropsychological tests involving selective attention under control conditions and during transcranial magnetic cortical stimulation. The tests chosen involved the recognition of a specific letter among different letters (verbal test) and the search for three different spatial orientations of an appendage to a square (visuo-spatial test). For each test the total time taken and the error rate were calculated. Results showed that cortical stimulation did not cause a worsening in performance. Moreover, magnetic stimulation of the temporal lobe neither modified completion time in both verbal and visuo-spatial tests nor changed error rate. In contrast, magnetic stimulation of the pre-frontal area induced a significant reduction in the performance time of both the verbal and visuo-spatial tests always without an increase in the number of errors. The experimental findings underline the importance of the pre-frontal area in performing tasks requiring a high level of controlled attention and suggest the need to adopt an interdisciplinary approach towards the study of neurone/mind interface mechanisms.

Adult↗
PubMedDate not supplied

[Doppler spectrum analysis and traditional angiography in the study of the extracranial tract of the internal carotid artery].

Examination of 88 extracranial carotid arteries using CW Doppler spectrum analysis is compared with the findings of transfemoral conventional arteriography. There is no significant difference (P greater than 0.05) between CWD and angiographic results, although sensitivity, specificity and accuracy are superior for the latter technique. CWD spectrum analysis can underestimate complete occlusion and misinterpret the degree of stenosis, however it is a cheap and rapid procedure that can be used to judge whether particular symptoms are due to identifiable disease and whether selective carotid arteriography is advisable.

Carotid Artery Diseases↗