Search PubMed⌕ Search

Biomedical subjects

P Picozzi

Publications and source records attributed to P Picozzi.

At least 37 records · Page 2Linked to original sources
PubMed1986

Quantitative measurement of cerebral blood flow and cerebral blood volume after cerebral ischaemia.

CBF obtained by the hydrogen clearance technique and cerebral blood volume (CBV) calculated from the [14C]dextran space were measured in three groups of rats subjected to temporary four-vessel occlusion to produce 15 min of ischaemia, followed by 60 min of reperfusion. In the control animals, mean CBF was 93 +/- 6 ml 100 g-1 min-1, which fell to 5.5 +/- 0.5 ml 100 g-1 min-1 during ischaemia. There was a marked early postischaemic hyperaemia (262 +/- 18 ml 100 g-1 min-1), but 1 h after the onset of ischaemia, there was a significant hypoperfusion (51 +/- 3 ml 100 g-1 min-1). Mean cortical dextran space was 1.58 +/- 0.09 ml 100 g-1 prior to ischaemia. Early in reperfusion there was a significant increase in CBV (1.85 +/- 0.24 ml 100 g-1) with a decrease during the period of hypoperfusion (1.33 +/- 0.03 ml 100 g-1). Therefore, following a period of temporary ischaemia, there are commensurate changes in CBF and CBV, and alterations in the permeability-surface area product at this time may be due to variations in surface area and not necessarily permeability.

Animals↗
PubMed1986

Recirculation after cerebral ischemia. Simultaneous measurement of cerebral bloodflow, brain edema, cerebrovascular permeability and cortical EEG in the rat.

The 4-vessel occlusion rat model of cerebral ischemia was modified to permit the simultaneous measurement of cerebral blood flow (hydrogen clearance), brain edema (specific gravity), cerebrovascular permeability (14C-AIB) and electrocardiogram. Surgery was performed in one stage in the anesthetised, paralysed and ventilated rat and severe hemispheric ischemia was produced in all animals. Electrode implantation did not alter cortical specific gravity or Ki for 14C-AIB. During 4-vessel occlusion mean cortical CBF was 5.8 +/- 1.4 ml-1 100 g-1 min. and this was associated with an isoelectric ECoG; 15 min of ischemia produced a significant reduction in mean cortical specific gravity (increase in brain edema). Following 15 min ischemia, 180 min of recirculation were permitted. Post-ischemic blood flow showed an immediate hyperemia (CBF = 202 +/- 12 ml-1 100 g-1 min.) followed by hypoperfusion (CBF = 58 +/- 8 ml-1 100 g-1 min). There was an early further decrease in cortical specific gravity. Further recirculation led to a significant increase in cortical specific gravity (resolution of brain edema). The transfer constant (Ki) for 14C-AIB was not altered at any stage in recirculation. This appears to be a model of pure cytotoxic edema until 180 min recirculation after 15 min cerebral ischemia. Recirculation permitted return of cortical electrical activity.

Animals↗
PubMed1985

Regional blood-brain barrier permeability changes after restoration of blood flow in postischemic gerbil brains: a quantitative study.

A quantitative technique utilising [14C]alpha-aminoisobutyric acid as a tracer was used to study cerebrovascular permeability in 22 Mongolian gerbils. Seven other animals were used to measure cerebral blood volumes. Global cerebral ischaemia was produced by temporary bilateral carotid artery occlusion (60 min) in 16 gerbils that were sacrificed at 1, 2, and 3 h following reperfusion. The blood-to-brain transfer constant was significantly increased after 2 h of reperfusion in the ischaemic zones and also in structures, like the cerebellum, not supplied by the carotid artery and not ischaemic during the vessel occlusion. The blood-brain barrier (BBB) alterations were coincident with the onset of ischaemia--induced seizures that were accompanied by sudden "spikes" of systemic blood pressure. Epilepsy may play an important role in the development of BBB damage in this ischaemic model, and this factor must be considered in the interpretation of BBB damage data in gerbils.

Aminoisobutyric Acids↗
PubMed1985

The role of cerebral blood volume changes in brain specific-gravity measurements.

Cerebral blood volume (CBV) was calculated in gerbils from specific-gravity (SG) changes between normal and saline-perfused brains. Furthermore, changes in CBV were investigated during ischemia using carbon-14-labeled dextran (MW 70,000) as an intravascular marker. Both data were used to evaluate the possible error due to a change in CBV on the measurement of ischemic brain edema by the SG method. The methodological error found was 0.0004 for a 100% CBV change. This error is insignificant, being less than the standard deviation in the SG measured for the gerbil cortex (SG 1.0494 +/- 0.0006). Thus, CBV changes are not responsible for the SG variations observed during the first phase of ischemia. These variations are better explained as an increase of brain water content during ischemia.

Animals↗
PubMed1982

Relation of cerebral vasospasm to operative findings of subarachnoid blood around ruptured aneurysms.

An investigation was carried out in 28 patients in order to evaluate the relationship between angiographically documented vasospasm, amount of subarachnoid blood found at surgery around ruptured intracranial aneurysms, and delayed ischaemic deficits. Angiography was performed at time intervals ranging between 5 and 17 days, and surgery not later than 21 days following subarachnoid haemorrhage. The absence of subarachnoid clots was associated in ten patients, with no or minor vasospasm and no or mild neurological deficits. Thin clots were found in eight patients; one of them had no vasospasm, six had minor vasospasm, and one showed severe vessel narrowing. Major clinical signs were absent in these cases. All ten patients with thick clots developed severe vasospasm, and eight of them severe neurological signs. The important aetiological role of local subarachnoid clots developed severe vasospasm, and eight of them severe neurological signs. The important aetiological role of local subarachnoid clots in determining vasospasm in emphasized in view of surgical timing.

Adult↗
PubMed1982

Neuroradiological findings in multiloculated hydrocephalus.

The characteristic neuroradiological features of multiloculated hydrocephalus following neonatal meningitis and ventriculitis in five infants are presented. The role of ventriculography and computerized tomography in detecting multiloculated and enlarged ventricles and paraventricular cavities, as well as complete and incomplete septa, is emphasized for early diagnosis and surgical management. CT scan also provides clues indicating the presence of thin but not visualized septa. It is suggested that post-meningitic hydrocephalus should be repeatedly followed-up for detection of multiloculated transformation. Probably this entity occurs less uncommonly than was thought in the past. The CT scan appears the most helpful and safe procedure for the serial evaluation, but ventriculography may be usefully combined with it in order to plan the most suitable operative approach for fenestration of membranes.

Cerebral Ventriculography↗
PubMed1982

Paramedian hourglass epidermoid extending above and below the tentorium.

The case of a 22-year-old woman with a large hourglass epidermoid tumor extending both below and above the tentorium is presented. The tumor was located in the suprasellar region, left middle cranial fossa, and posterior fossa on the left side. Conventional computerized tomographic (CT) scanning was inconclusive as to the actual extension of the tumor, whereas air encephalography was more helpful. The subtemporal transtentorial approach made it possible to achieve a seemingly radical excision of the tumor. Nevertheless, the CT scan one year later showed the presence of a small tumor mass. The diagnostic and surgical implications are discussed in light of few similar cases reported in the literature.

Adult↗
PubMed1981

Choroid plexus papilloma of the third ventricle.

Choroid plexus papillomas are rarely located in the third ventricle. The case of a 49-year-old man who had a total microsurgical excision of such a lesion is reported. The neuroradiological features and the surgical results are discussed, with a review of 25 other cases reported in the literature. Microsurgical technique made possible a good exposure and successful complete removal of the tumor.

Cerebral Ventricle Neoplasms↗