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G Tomei

Publications and source records attributed to G Tomei.

At least 37 records · Page 2Linked to original sources
PubMed1998

Neuroendocrine, immunohistochemical, and ultrastructural study of pineal region tumors.

Thirteen patients with tumors in the pineal region were submitted to pre- and post-operative blood sampling (08:00, 14:00, 20:00, and 02:00 hr) for three or four consecutive days. A single cerebrospinal fluid (CSF) sample was collected at surgery, and melatonin levels determined. In all patients, serum and CSF beta subunit of human chorionic gonadotrophin (betaHCG), carcino embryonic antigen (CEA), and alpha-fetoprotein (AFP) levels were measured. Histology revealed four pineocytomas, one pineoblastoma, four germinomas, one immature teratoma, one pilocytic astrocytoma, one lymphoma, and one meningioma. Serum and CSF levels of serological biomarkers were normal, except for one of the germinoma cases. In most patients, alteration either in the circadian rhythm or in the melatonin concentration was observed before surgery. In benign neoplasms the circadian rhythm was conserved. In pineoblastoma, lymphoma, and three out of four germinomas, melatonin concentrations were undetectable. In one case of germinoma, melatonin levels were high, with the circadian rhythm being abolished. According to conventional histology, all germinomas were similar. Therefore, in a rare case of pineal germinoma with high melatonin levels, the tissue was subjected to an in depth investigation (immunohistochemical and ultrastructural) in order to determine the pathology and the possible differences from the other typical germinomas. Results were compared to those provided from other pineal neoplasms. Electron microscopy examination detected the presence of clusters of intermediate filaments and numerous electrondense granules only in the case of a germinoma producing melatonin.

Adult↗
PubMed1997

Long-term results of treatment for craniopharyngioma in children.

Results of the treatment of 27 children with craniopharyngioma are reported. A subfrontal pterional approach was used in 55.6% of cases, a transsphenoidal and a transcallosal or transcortical approach in 25.9% and 18.5% of cases, respectively. Radical removal was the goal of surgery and was achieved in 70.8% of cases treated as primary surgery. The operative mortality was 3.7% and was due to hypothalamic failure. Most (81.4%) patients were followed up, for a mean of 7 years. Patients were evaluated according to a functional evaluation scale and outcome categories proposed by us. The scale takes account of tumor (recurrences and their eventual evolution); visual functions; endocrine functions (mainly hypothalamic), attainment of endocrine balance and drug regimen; headache; and psychosocial function. Recurrences were observed in 17.6% of patients treated with radical surgery and in 42.8% of those treated with limited surgery plus radiotherapy. A progressive amelioration of visual, endocrine and neuropsychosocial functions from the intervention to follow-up was observed in the majority of patients. Complete tumor excision was associated in 85% of cases with a low score on the functional scale, reflecting a high functional performance. Adequate substitution therapy maintained endocrine balance in 81% of patients. Since the intervention a progressive decrease in the number and dosages of medications has been observed. The majority of patients were again able to lead a normal social life. Small stature, obesity, headache, and emotional and sexual disturbances were frequent cause of long-term disability even despite adequate drug regimens. The functional evaluation scale we propose is a simple and effective tool that can be easily used during routine evaluation of patients with craniopharyngioma.

Adolescent↗
PubMed1997

Transcallosal approach to tumors of the third ventricle. Surgical results and neuropsychological evaluation.

A series of 34 patients with tumours of the third ventricle were operated on by a transcallosal route. Basal extrinsic lesions compressing or invading the ventricle as well as tumours located in the pineal area were excluded from this review. Tumours were approached by a transforaminal entry in 16 cases (47%), by an interforniceal route in 11 (32%), by a subchoroidal entry in 4 (14%) and by a combined transforaminal and subchoroidal entry in 3 (9%). Four out of 34 patients were submitted to a second operation, through the same approach corridor: 2 for an incomplete removal of an intrinsic tumour and 2 for a late regrowth. Postoperative mortality rate accounted for 5.8% (2 patients). Major post operative complications were hemiparesis (4 patients) and diabetes insipidus (4 patients), that were transient in 3. Akinetic mutism like status was observed in only 1 patient. Postoperative psychic disturbances were noticed in 5 cases. Nine out of 21 patients (62%) with preoperative hydrocephalus required a permanent CSF shunt. Histology revealed that 21 tumours (62%) were intraaxial (4 pilocitic astrocytoma, 10 low grade glioma, 1 giant cell astrocytoma, 1 subependymoma, 4 ependymoma/ependymoblastoma, 1 neurocitoma) and 13 (38%) were extraaxial (8 colloid cyst, 2 craniopharingioma, 1 ectopic pituitary adenoma, 1 lymphocytic hypophysitis and 1 metastasis). Total excision of third ventricle tumours was achieved in all patients with extraaxial tumours and in 62% and 71% of intraaxial tumours with the first and second surgical procedure respectively. Ten out of 34 patients of this series were submitted to a complete neuropsychological evaluation at an interval of 2-9 years after surgery. Memory tests were pathological in 2. Disconnection signs were constantly absent. Control function were preserved. Transcallosal approach remains the best microsurgical method of third ventricle tumours treatment. This route provides the capability for a superior visualization of the entire cavity of the third ventricle through different corridors. Permanent neurological and neuropsychological deficits are not frequent. Epilepsy, that accounted for 28% in patients submitted to transcortical transventricular approach to third ventricle tumours, was never noticed in this series operated on through a transcallosal route.

Adolescent↗
PubMed1995

Central nervous system trans-synaptic effects of acute axonal injury: a 1H magnetic resonance spectroscopy study.

N-acetylaspartate (NAA) has previously been proposed as a neuronal marker. 1H magnetic resonance spectroscopy (MRS) is able to detect NAA in brain, and decreases of NAA have been documented after brain injury. The reason for this decrease is not fully understood and neuron loss damage and "dysfunction" have all been proposed. It is hypothesized that acute central nervous system (CNS) deafferentation causes a trans-synaptic NAA decrease and that high resolution 1H MRS is able to detect such a decrease. To test this hypothesis, an experimental model was used in which axonal lesions were obtained by stretch injury in guinea pig right optic nerve (95-99% crossed fibers). The trans-synaptic concentration of NAA, total creatine (Cr), and the NAA/Cr ratio in lateral geniculate bodies (LGB) and superior colliculi (SC) sample extracts were measured 72 h later by high resolution 1H MRS. In the left LGB/SC, which is where right optic nerve fibers project, reductions of NAA and NAA/Cr were found whereas Cr levels were normal. NAA, NAA/Cr, and Cr values were all normal in the right LGB/SC. Histology and EM findings revealed no abnormalities. At 7 days, left LGB/SC NAA and NAA/Cr values were in the normal range. It was concluded that 1) acute deafferentation in the CNS causes a trans-synaptic decrease of NAA levels that can be detected by 1H MRS and 2) NAA decrease may be due to changes of NAA metabolism caused by functional neuronal inactivity rather than neuronal loss, injury or "dysfunction." 1H MRS is a potential tool for the study of functional effect of CNS lesions in vivo.

Animals↗
PubMed1995

Long-term outcome in aqueductal stenosis.

In this study, 78 patients with aqueductal stenosis were submitted to detailed neurodevelopmental assessment with a follow-up of 5-25 years. Sixty-eight percent of patients were categorized as normal; they either attended normal school courses or had regular jobs. Among these, 34% had some motor abnormalities (ataxia, mild hemiparesis, visual disturbances). Twenty-four percent (19 cases) were moderately disabled (trainable retardation) and 8% (6 cases) were severely handicapped. Epilepsy was observed in 13% of the cases. Incidence of recurrent and generalized seizures paralleled neurodevelopmental outcome (5% in normal, 16% in moderately disabled and 50% in severely disabled patients). Endocrine dysfunctions were evident in 28% of the cases and were characterized by precocious or delayed puberty, amenorrhea and somatic underdevelopment. No patient with ventricular enlargement and a cortical mantle width below 20 mm showed a good outcome. Large ventricles were compatible with normal mental development when compensated with a corresponding cranial vault enlargement. In patients with normal mental status and motor abnormalities, long-term CT scan findings revealed the presence of focal brain abnormalities (poroencephaly, brain atrophy, calcifications, extracerebral collections).

Adolescent↗
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↗
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

Clinicoradiological and therapeutic considerations in severe diffuse traumatic brain injury in children.

Forty-one children with severe head injuries and diffuse brain lesions were selected from a consecutive series of 62 children in traumatic coma (21 focal mass lesions) and studied. According to the CT pattern, two main types of intracranial lesions were considered: diffuse axonal injury (DAI) and diffuse brain swelling (DBS). High mortality, due to secondary increases of intracranial pressure (ICP), correlated well with the patterns of severe DBS, absence of perimesencephalic cisterns, and obliteration of the ventricles. However, children with normal CTs, and/or obvious shearing injuries indicative of DAI, had favorable outcomes; there was no mortality if increased ICP was not present. We conclude that although there does not seem to be any routine indications for ICP monitoring in children with pure DAI, early ICP monitoring and aggressive management of increasing ICP should be considered in comatose children with DBS, especially when associated with subarachnoid hemorrhage and respiratory or circulatory failure.

Adolescent↗
PubMed1989

Cerebral blood flow velocity and cerebrospinal fluid pressure after single bolus of propofol.

The effects of propofol on cerebral blood flow velocity, cerebrospinal fluid pressure, cerebral perfusion pressure and mean arterial pressure were studied during induction in 25 patients scheduled for elective craniotomy. Premedication consisted of only atropine sulphate 0.007 mg/kg (im) 45 min before induction. Measurements were made or derived at time zero and 1, 2, 3, 4 and 5 min after an induction dose of propofol (2.5 mg/kg). Patients were retrospectively stratified into two groups, according to cerebrospinal pressure basal values: (i) lower than 10 mmHg (10 pts) and (ii) higher than 10 mmHg (15 pts). Cerebral blood flow velocity, measured by transcranial Doppler, fell in all the patients, but the reduction was significant at 1, 2, 3 and 4 min only in the group with high CSF pressure, while it never reached the critical value of 10 cm/s. Cerebrospinal fluid pressure and mean arterial pressure decreased in both groups of patients and the fall reached a statistical significance at 1 and 2 min in the group with higher baseline CSF pressure, only at 1 min: a parallel decrease of CPP was recorded, but it was not significant. Thus propofol decreases CSF pressure without hazardous effects on cerebral blood velocity and on cerebral perfusion pressure and seems to be a suitable anaesthetic agent in controlling high cerebrospinal fluid pressure in neuroanaesthesia.

Adult↗
PubMed1989

Axonal injury in the optic nerve: a model simulating diffuse axonal injury in the brain.

A new model of traumatic axonal injury has been developed by causing a single, rapid, controlled elongation (tensile strain) in the optic nerve of the albino guinea pig. Electron microscopy demonstrates axonal swelling, axolemmal blebs, and accumulation of organelles identical to those seen in human and experimental brain injury. Quantitative morphometric studies confirm that 17% of the optic nerve axons are injured without vascular disruption, and horseradish peroxidase (HRP) studies confirm alterations in rapid axoplasmic transport at the sites of injury. Since 95% to 98% of the optic nerve fibers are crossed, studies of the cell bodies and terminal fields of injured axons can be performed in this model. Glucose utilization was increased in the retina following injury, confirming electron microscopic changes of central chromatolysis in the ganglion cells and increased metabolic activity in reaction to axonal injury. Decreased activity at the superior colliculus was demonstrated by delayed HRP arrival after injury. The model is unique because it produces axonal damage that is morphologically identical to that seen in human brain injury and does so by delivering tissue strains of the same type and magnitude that cause axonal damage in the human. The model offers the possibility of improving the understanding of traumatic damage of central nervous system (CNS) axons because it creates reproducible axonal injury in a well-defined anatomical system that obviates many of the difficulties associated with studying the complex morphology of the brain.

Animals↗