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Biomedical subjects

R Villani

Publications and source records attributed to R Villani.

At least 37 records · Page 2Linked to original sources
PubMed1990

Morphology and neurophysiology of focal axonal injury experimentally induced in the guinea pig optic nerve.

A new model of focal axonal injury was reproduced by rapid and controlled elongation (uniaxial stretch) of the guinea pig optic nerve. Light microscopy study of optic nerve specimens after horseradish peroxidase injection into the vitreous of the animal's eye showed that axonal lesions were identical to those seen in human and primate post-traumatic diffuse axonal injury (DAI). The lesions were characterized by the formation of terminal clubs in severed axons and focal axonal enlargements in those axons that were lesioned-in-continuity. Visual-evoked potentials upon flash stimulation were recorded before and after injury. Mean amplitude and mean latency of occipital peaks were significantly elongated in the acute post-traumatic phase. Electron microscopy examination showed that the main axonal changes observed in this model were cytoskeleton disorganization, accumulation of axoplasm membrane-bound bodies at the site of terminal balls and dilatations-in-continuity and detachment of the axolemma from the myelin sheath. Such axonal alterations were similar to those found in many other biological models of central and peripheral axonal injuries in which the lesion was produced by invasive methods. This model is unique since it reproduces the same mechanism of injury and the identical lesions that have been demonstrated in humans and primates with post-traumatic (DAI).

Animals↗
PubMed1990

Treatment of intracranial meningiomas in patients over 70 years old.

The neurosurgeon often finds himself in the position to having to decide whether or not to operate on an elderly patient suffering from intracranial meningioma. The decision is rarely easy and the results often disappointing. We studied 46 cases of intracranial meningioma in patients over 70 years of age, 34 patients were operated on while 12 patients were not, although both groups were subjected to long term follow-up. The operative mortality rate was 12%, a rate which increased to 20% at 3 months follow-up. Various unfavourable prognostic factors were taken into consideration, the most significant of which were: poor overall clinical condition, peritumoral oedema, the presence of diabetes mellitus and the duration of surgery. A scored grading system was created to standardize surgical indications in elderly patients with cerebral meningioma. An analysis of the grading system, when applied to patients submitted to surgery, showed that the decreased patients within 3 months of surgery had a score which varied from 7 to 12, with a mean score of 10. The surviving patients had a score averaging from 10 to 16 with a mean of 13. The patients with the lowest scores (7-9) had a 100% mortality rate while those in the upper ranges (13-16) demonstrated a mortality rate of 0%. Among the conservatively treated patients the worst outcome was seen in patients with a grading equal to or less than 12.

Aged↗
PubMed1990

[Anesthesia, awareness and wakefulness].

Drugs used in anesthesia do not always produce the expected neurophysiological results. By studying those cases in which the reappearance of intraoperative awareness is most common, an attempt was made to estimate how many and which levels of cerebral function could be identified. Four levels were recognised: awareness with or without memory, and wakefulness with or without dreams. These conditions are related to greater or lesser cortical activity. They can be identified using Tunstall's technique and by carefully interviewing the patient immediately after the operation.

Adult↗
PubMed1989

Primary intracranial rhabdomyosarcoma: report of two cases.

Primary intracranial rhabdomyosarcoma (RMS) is a rare tumor in infancy and childhood that is found in various locations in the central nervous system. The clinical course worsens rapidly, and the final outcome is poor, with a median survival time of 8-10 months. Invasion of the meninges, spontaneous intratumoral bleeding, spinal leptomeningeal CSF spreading of tumor cells, and early recurrence of the mass are the distinctive features of RMS. Diagnosis of RMS may be missed: immunohistochemical staining using specific markers (myoglobin, myosin, desmin, vimentin, enolase), along with ultrastructural studies, provide the basis for making the final diagnosis. Treatment of RMS includes surgical excision, craniospinal radiation therapy, and chemotherapy. We report two cases of primary RMS in the CNS located in the posterior fossa and frontotemporal area. Both children underwent total surgical removal of the mass. Early recurrence of the tumor mass was noticed in both patients 2 months after surgery. Both children died shortly thereafter.

Adolescent↗
PubMed1989

Neuropsychological outcome of patients operated upon for an intracranial aneurysm: analysis of general prognostic factors and of the effects of the location of the aneurysm.

One hundred and fourteen patients operated on for an intracranial aneurysm were followed up in order to investigate their neuropsychological outcome and to detect if there were any clinical features assessed around the time of operation that had prognostic significance. The neuropsychological examination evaluated language, apraxia, memory, intelligence and spatial ability. In the statistical analysis the overall severity of neuropsychological disorder was studied. "Late surgery timing" had a negative influence upon the neuropsychological outcome. There was not a difference between different aneurysm sites. Several patients with an apparently good clinical outcome showed neuropsychological deficits. Neuropsychological assessment is important in the evaluation of outcome after subarachnoid haemorrhage.

Adolescent↗
PubMed1989

[Diffuse traumatic cerebral injuries in children].

A consecutive series of 41 patients aged less than 16 and admitted to the Department of Neurosurgery of the University of Milan in the period 1977-1978 following serious cranioencephalic trauma with Glasgow Coma Score (GCS) less than or equal to 7, duration of coma longer than 24 h and CT picture of diffuse lesion has been examined. These patients account for 5% of the paediatric cranial traumas observed in the same period and 66% of those in a state of coma. The CT picture made it possible to split patients into 3 groups: a) those without visible cerebral lesions and with subarachnoid and cisternal spaces present; b) those with small hyperdense lesions due to intraparenchymal or median/paramedian subcortical shearing lesions; c) those with marked constriction or absence of the 3rd ventricle and of the perimesencephalic cisterns. The first two pictures (a, b) were considered to be the expression of diffuse axonal damage, the last (c) of diffuse cerebral swelling. Intracranial pressure was monitored in about 50% of patients. The overall outcome of the series was favourable in more than 68% of cases with total mortality of 26.8%. Analysis of individual tomographic categories, however, showed that whereas the group of patients with diffuse axonal lesion presented nil mortality, those with diffuse cerebral swelling had 52% mortality owing to the onset of refractory intracranial hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Monitoring of brain function by means of evoked potentials in cerebral aneurysm surgery.

Deliberate arterial hypotension is currently used to operate upon cerebral aneurysms. However, it is not ascertained whether this practice is really safe for all patients, especially those presenting with preoperative vasospasm. 50 patients, requiring surgical treatment for cerebral aneurysm, have been submitted, during surgery, to the recording of Somatosensory Evoked Potentials (SEPs) on median nerve stimulation. This technique allows the functional evaluation of neural pathways mediating the somatosensory stimuli and of primary somatosensory cortex; it is known that a decrease of cerebral perfusion may affect the SEP waveforms in terms of reduced subcortical conduction velocity (i.e., increased central conduction time, CCT) and of reduced cortical response amplitude. These changes may be apparent before a permanent neurological damage is produced. Preoperative SEP recording demonstrated a prolonged CCT, possibly related to vasospasm, in 9 patients, a normal clinical evaluation notwithstanding (grade I and II). During intraoperative deliberate hypotension, a SEP change has always been produced. No postoperative damage has been observed, however, as long as the CCT did not exceed 9 msec for 10 minutes (maximum normal CCT value is 6.7 msec) and as the cortical response had been visible throughout the whole surgical procedure. The critical value of CCT has been reached at a mean arterial pressure (MAP) lower than 60 Torr in patients with a normal preoperative SEP recording; at the opposite, in patients presenting with a prolonged preoperative CCT, the value of 9 msec was arrived at with a MAP value that is generally accepted as safe for all patients (75 Torr).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1988

Pattern reversal visual evoked potentials in phenylketonuria.

The pathogenesis of brain dysfunction in phenylketonuria (PKU) is still under investigation. Hyperphenylalaninaemia results in increased turnover of myelin. In order to demonstrate the derangement of myelinization in PKU we studied the visual evoked potentials (VEP) in 14 PKU patients and in 20 normal subjects. VEP findings were correlated with the metabolic control of the disease and with the electroencephalographic findings. VEP were more sensitive than the EEG in detecting a neurological dysfunction. VEP are influenced by dietary control and are normal only in children with good metabolic control.

Adolescent↗
PubMed1987

Pattern-reversal visual evoked potentials in phenylketonuric children.

Pattern-reversal visual evoked potentials (PR-VEPs) and EEG were recorded in 14 phenylketonuric (PKU) children on a low-phenylalanine (phe) diet; the data obtained were correlated with metabolic parameters, namely, the actual phe plasma level, the mean phe plasma level in the last year, an the beginning of the diet. PR-VEPs seem to be more sensitive than EEG in detecting neurophysiological derangements in these subjects; in fact PR-VEPs were pathological in six patients while EEG detected three; no significant alterations were found in the neurophysiological tests among the children with good metabolic control, and only one child was abnormal among the six on an early dietetic regimen; in contrast, six of the nine subjects presenting with high mean phe plasma levels (greater than 10 mg/100 ml) and five of the eight whose diet started after the 2nd month of life showed pathological PR-VEPs.

Adolescent↗
PubMed1987

Solitary plasmacytoma of the calvarium: two cases treated by operation alone.

Two cases of solitary plasmacytoma of the calvarium operated on with radical removal are reported. The two patients were not submitted to postoperative radiotherapy, unlike other cases reported in the literature. The authors stress that solitary plasmacytoma of the calvarium may have a good prognosis if radically removed, and in these cases radiotherapy is not necessary.

Adult↗
PubMed1986

[Right cardiac echinococcosis with coronary compression. Description of a clinical case].

An outstanding case of cardiac echinococcosis is described. Clinical symptomatology was characterized by typical nitroglycerin-responsive crisis of angina pectoris associated to an electrocardiographic pattern of negative T wave on anterolateral and inferior leads. The diagnosis was suspected on the basis of thoracic computerized tomography and coronary arteriography. The anatomical localization was mainly pericardial but the right ventricle was involved too. Left anterior descending artery was dislocated and squeezed.

Adult↗
PubMed1985

Changes in visual evoked potentials in children on chronic dialysis treatment.

Visual evoked potentials (VEP) were recorded in 20 children undergoing dialysis for chronic renal failure. VEP before treatment (72 h after last dialysis) were pathological in 17 patients (85%); responses obtained 3 h after treatment were abnormal in only 6 cases (30%). Furthermore, all patients improved after treatment, except two who were unchanged. However, VEP recorded immediately after dialysis were worse in 4 of 7 patients than before treatment, probably as an effect of the dysequilibrium syndrome; they improved spontaneously afterwards. The acute changes caused by dialysis seem to be more evident in children than in adults. No correlations have been found between blood chemistry indexes and VEP modifications. Finally, VEP have proved to be more sensitive than EEG in identifying a central nervous system (CNS) dysfunction in these uremic patients.

Adolescent↗
PubMed1983

Multiple forms of protein kinase from normal human brain and glioblastoma.

The biochemical characteristics of the protein kinase (PK; adenosine triphosphate-protein phosphotransferase, EC 2.7.1.37) isozymes in subcellular preparations from normal human brain cortex and glioblastoma were investigated after chromatography on diethylaminoethyl cellulose, and the following results have been obtained. Two major isozyme forms, eluted by 50 and 200 mM phosphate buffer, are present in both cytosol and membrane-derived preparations from cerebral cortex. Furthermore, these isozyme forms have properties similar to those referred to as type I and type II cyclic adenosine 3':5'-monophosphate-dependent PK. In these chromatographic isozymes, cyclic adenosine 3';5'-monophosphate is more active in stimulating the basal PK enzyme than is cyclic guanosine 3':5'-monophosphate. In glioblastoma, the PK activity from cytosol and particulate preparations is resolved by diethylaminoethyl cellulose in four peaks. In cytosol, the major portion of the enzyme is eluted with a 300 mM buffer (about 50% of the total basal PK activity) and is cyclic nucleotide dependent. On the contrary, in glioblastoma particulate, the PK enzyme is mainly eluted at 50 and 100 mM buffer; neither of these isozymes is cyclic nucleotide dependent. As for cytosol, only the particulate isozyme eluted at 300 mM buffer is strongly activated by cyclic nucleotides. Finally, in both glioblastoma subcellular preparations, only a type II cyclic adenosine 3':5'-monophosphate-dependent PK is present.

Brain↗