[Effects of hyperventilation on acid base equilibrium and cerebral metabolism in experimental focal ischemic lesions].
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Acid-Base Equilibrium↗
Biomedical subjects
S Passero
Publications and source records attributed to S Passero.
[Repeated measurements of local cerebral flow during normal ventilation and hyperventilation in occlusion of the middle cerebral artery in the cat].
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Animals↗
Quantitative EEG mapping, regional cerebral blood flow, and neuropsychological function in Alzheimer's disease.
The relations between quantitative EEG, regional cerebral blood flow (rCBF), severity of disease and neuropsychological data were analyzed in 31 patients in different stages of Alzheimer's disease (AD). As a group the demented patients had higher delta and theta activities, lower alpha activity and lower alpha peak frequency than control subjects. rCBF was reduced in all regions studied but mainly in the temporoparietal areas. An analysis of correlations showed a close relationship between rCBF and certain quantitative EEG parameters in AD patients, mainly the power of the theta and delta bands. Both rCBF evaluation and quantitative EEG provide functional information related to the severity of cognitive impairment.
Aged↗
Platelet embolism in rabbit brain.
Transient cerebral ischemia was induced in rabbits by selective infusion of arachidonic acid (0.35 mg/kg in 15 sec) into the internal carotid artery. Platelet emboli caused transient ischemia of the brain, reaching a maximum within a few seconds after injection. After embolism the EEG flattened, blood flow stopped in almost the entire injected hemisphere, cortical pH gradually fell from 7.31 +/- 0.09 to 7.05 +/- 0.10 and cortical K+ activity rose from 4.7 +/- 1.8 to 12.7 +/- 6.4 mmol/kg H2O. Complete ischemia lasted 3-5 min; then cerebral circulation was gradually restored without reactive hyperemia. Forty-five min after embolization, circulation had been resumed in almost the entire injected hemisphere, whereas metabolic changes were still disturbed. Eighty percent of the animals recovered complete neurological function and 20% showed permanent damage confirmed by histological examination after 1 week of recovery.
Animals↗
Animal model of TIA: an experimental study with intracarotid ADP infusion in rabbits.
Adenosine diphosphate (8 mg per minute for five minutes) was infused into the carotid artery of 63 rabbits. The effects were twofold: systemic hypotension and platelet aggregation in the cerebral circulation. As a consequence of the last effect, platelet emboli were produced which occluded cerebral arteries in a number and size sufficient to cause cerebral ischemia. Areas of focal ischemia were observed through a cranial window, and documented with antipyrine autoradiography. Platelet thrombi were almost entirely transient, being fragmented and removed within a very short time of cessation of ADP infusion. Consequently, no permanent tissue damage ensued. This experimental model approaches the spontaneous transient ischemia attacks (TIAs) in man, demonstrating that these can be caused by pure platelet emboli. A high cholesterol diet administered for two months prior to ADP infusion did not enhance the effect of the procedure or make the platelet aggregation and the following ischemia longer in duration or more severe.
Adenosine Diphosphate↗
[CAT and MRI in the study of partial epilepsy: comparison of the 2 methods and correlations with EEG].
Seventy five adult patients suffering from partial epilepsy were investigated by MRI. Results were then compared with those obtained with CT scan and EEG analysis. The interval between the two neuroradiological studies did not exceed five years. MRI and CT showed abnormalities respectively in 45 and 55% of patients, MRI showed a better sensitivity in detecting ischemic or atrophy-gliosis chronic focal alterations. In the remaining lesions such as tumors, vascular malformations, cysts and diffuse atrophies, where often an urgent diagnosis is necessary, both tests were equally sensitive. EEG showed alterations in 80% of patients and agreed with results of CT scan and MRI in about 80% of cases.
Adolescent↗
[Ophthalmoparesis as a presentation form of subacute euthyroid thyroiditis].
The present study describes a case of subacute thyroiditis characterized by involvement of ocular motility that appeared many months before bioumoral findings of the disease. The authors believe that when the etiological diagnosis of an ophthalmoparesis, especially when isolated, is uncertain, one must carefully evaluate the function of the thyroid and levels of the specific antibodies, in order to start the appropriate treatment.
Female↗
[Maps of somatosensory evoked potentials from the arm in patients with neoplasms and post-traumatic brain lesions].
Short-latency somatosensory evoked potentials by the stimulation of the median nerve at the wrist, were recorded in six patients (four with cerebral tumors and two with post-trauma lesions). The electrodes were placed on the scalp following the 10-20 International System. A reference electrode was placed on earlobe contralateral to the site of the stimulation. Eleven normal subjects were used as control (mean age 64.4 +/- 12.05). We used the Brain-Surveyor-Basis Trade system which allowed us to elaborate the results by coloured mapping through linear interpolation of signal amplitudes. The following parameters were investigated: peak latencies of the N13, N20, P22, N30 waves; amplitudes of the post-rolandic P14-N20, N20-P25, pre-rolandic P22-N30 components and the central conduction time N13-N20 (CCT). The evaluation of latencies was not significant in determining the lesion site. On the contrary, the evaluation of amplitudes revealed expressive asymmetry, though it did not define the nature of alteration (increase or decrease due to lesion), and the correlation between these variations and the site of the lesion. The authors discussed the possibility that amplitude abnormalities in patients with tumors were related either to the tumors and/or drug effects.
Adult↗
[Palm stimulation in carpal tunnel syndrome].
In order to verify the sensory nerve conduction velocity (SNCV) by median nerve palmar stimulation regard to each single finger, we tested 48 patients with typical CTS symptoms, confirmed by neurophysiological examination. The control group consisted of twenty-seven healthy volunteers, of similar mean age. The SNCVs were obtained by stimulating the II finger (M2), III (M3), IV (M4) and II and III intermetacarpo-phalangeal site (respectively P2 and P3) for median nerve; IV finger (U4) and IV intermetacarpophalangeal site (P4) for ulnar nerve. Data show that P2 was normal in 3 cases (6.2%), as was M2; M3 in 2 cases (4.2%) and P3 only in one case (2.1%). No sensory nerve action potential was recorded in 3 case (6.2%) during P3 stimulation, in comparison to 14 cases (29.2%) during M4 stimulation. When each case was examined separately, the behaviour of palmar SNCV resulted similar to the corresponding fingers. Finally, the ratio between SNCV values of P2/P3, with respect to controls, showed a further more severe damage of P3 compared to the P2, generally preferred by other authors.
Action Potentials↗
Bilateral vestibular loss in vertebrobasilar dolichoectasia.
Bilateral vestibular loss (BVL) is a relatively uncommon syndrome that may produce problems of balance; unsteady gait, especially in the dark; and visual disorders and/or oscillopsia associated with walking and head movements. Sometimes patients with BVL remain asymptomatic. Ototoxic drugs are the most frequently identified cause of BVL, but there are many other possible causes. The aetiology remains unknown in a large percentage of patients. In some, vascular aetiology may be suspected. Here we report 4 cases of vertebrobasilar dolichoectasia (VBD) and symptomatic BVL. In 3 subjects, hearing was preserved, but in the 4th, there was retrolabyrinthine hearing loss. In our opinion, VBD may be the cause of BVL associated or not associated with hearing loss, the reason being that since the anterior vestibular artery is small and has no anastomoses, the horizontal semicircular canal is selectively susceptible to ischemia.
Aged↗