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Biomedical subjects

G Pizzolato

Publications and source records attributed to G Pizzolato.

At least 19 recordsLinked to original sources
PubMed2004

Does liver-disease aetiology have a role in cerebral blood-flow alterations in liver cirrhosis?

BACKGROUND: Studies using brain-imaging techniques have shown changes in regional blood flow (rCBF) in patients with liver cirrhosis. It remains unknown whether the aetiology of liver disease accounts for these changes. AIMS: To evaluate whether the aetiology of liver cirrhosis is associated with different patterns of rCBF. MATERIALS AND METHODS: A total of 50 patients with end-stage liver disease and no overt encephalopathy were studied. Thirteen age-matched subjects admitted to the neurology department for headache were used as controls. Exclusion criteria were focal brain lesions, severe brain atrophy and any abnormalities found on computed tomography scan suggesting other central nervous system diseases, alcohol intake or use of neuroactive drugs for at least 6 months. rCBF was assessed using single-positron-emission tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (99mTc-HM-PAO) as a tracer in all patients and controls. The Mann-Whitney U test was used for statistical analysis. RESULTS: The liver-disease aetiology was as follows: alcoholic (A) in 19 patients; viral (V) (hepatitis B virus, hepatitis D virus, hepatitis C virus) in 14 patients; alcoholic with concomitant viral (A + V) in five patients; and cholestatic (C) (primary biliary cirrhosis, primary sclerosing cholangitis) in 12 patients. SPECT showed significantly lower rCBF in cirrhotic patients than in controls for most cortical and subcortical regions and in alcoholic and viral patients than in cholestatic liver disease patients for some cortical regions. When patients were grouped according to previous alcohol abuse (including cases with a concomitant viral aetiology), rCBF was significantly lower in the frontal superior, medial and temporal inferior regions in the alcoholic group. CONCLUSIONS: Cerebral blood flow is significantly lower in patients with liver cirrhosis than in controls and, among cirrhotics, it is lower in alcoholic and viral cirrhosis than in cholestatic liver disease. In patients with previous alcohol abuse, cerebral blood flow was significantly more reduced in the frontal and temporal regions compared with patients without previous alcohol abuse.

Adult↗
PubMed2004

Thiethylperazine-induced parkinsonism: in vivo demonstration of dopamine D2 receptors blockade.

Thiethylperazine (Torecan) is a piperazine phenothiazine employed to relieve vertigo. Its use may be associated with extrapyramidal side effects (dystonia, akathisia, tardive dyskinesia) (Sulkava, 1984), but parkinsonism has rarely been described. We describe a woman who, 1 month after the onset of thiethylperazine treatment, developed parkinsonism that disappeared 2 months after withdrawal of the drug. However, cerebral single-photon emission computed tomography (SPECT) with the dopamine (DA) D2 receptors ligand 123I-iodobenzamide (123I-IBZM) revealed a persistent reduced DA D2 receptors activity (by 45%) in the basal ganglia (BG), which may be clinically not effective.

Basal Ganglia↗
PubMed2002

Combined analysis of CSF betaA42 peptide and tau protein and serum antibodies to glycosaminoglycans in Alzheimer's disease: preliminary data.

Neuropathological hallmarks of Alzheimer's disease (AD) are amyloid plaques and neurofibrillary tangles, containing betaA(42) peptide and tau protein, respectively. Amyloid plaques contain also glycosaminoglycans (GAGs). Whereas cerebrospinal fluid (CSF) levels of betaA(42) peptide and tau protein have been demonstrated as potential markers of Alzheimer's disease (AD), no data are available for GAGs. We determined (Elisa) tau and betaA(42) CSF levels, as well as serum antibodies to GAGs in 9 AD patients, and the values were analyzed in relation to age and severity of the disease. Beta-A42 and tau CSF levels were significantly reduced and increased, respectively, in AD patients when compared to controls, but they did not correlate with the severity of the disease. Despite their role in amyloidogenesis, we did not find evidence for the use of GAGs as diagnostic marker of AD.

Aged↗
PubMed2002

A short review of cognitive and functional neuroimaging studies of cholinergic drugs: implications for therapeutic potentials.

In the last 20 years a cholinergic dysfunction has been the major working hypothesis for the pharmacology of memory disorders. Cholinergic antagonists and lesions impair and different classes of cholinomimetics (i.e. acetylcholine precursors, cholinergic agonists and acetylcholinesterase inhibitors) enhance attention and memory in experiment animals, healthy human subjects and Alzheimer disease patients. In addition, acetylcholinesterase inhibitors improve different cognitive (i.e. visuospatial and verbal) functions in a variety of unrelated disorders such as dementia with Lewy bodies, Parkinson disease, multiple sclerosis, schizoaffective disorders, iatrogenic memory loss, traumatic brain injury, hyperactivity attention disorder and, as we recently reported, vascular dementia and mild cognitive impairment. In animals, different cholinomimetics dose-dependently increased regional cerebral metabolic rates for glucose (rCMRglc) and regional blood flow (rCBF), two indices of neuronal function, more markedly in subcortical regions (i.e. thalamus, hippocampus and visual system nuclei). In both healthy human subjects and Alzheimer disease patients acetylcholinesterase inhibitors increased rCMRglc and rCBF in subcortical and cortical brain regions at rest but attenuated rCBF increases during cognitive performances. Hence, acetylcholinesterase inhibitors may enhance cognition and rCMRglc by acting primarily on subcortical regions that are involved in attentional (i.e. thalamus) and memory (i.e. hippocampus) processes; such an effect probably is not specific for Alzheimer disease and can be beneficial in patients suffering from a wide array of neuropsychiatric disorders.

Alzheimer Disease↗
PubMed2001

Role of the distal balloon protection technique in the prevention of cerebral embolic events during carotid stent placement.

BACKGROUND AND PURPOSE: We sought to quantitatively and qualitatively evaluate the release of atheromatous plaque debris induced by carotid stenting procedures. METHODS: Eight patients with severe carotid atheromatous stenoses were treated by stent implantation under distal balloon protection. Blood samplings were obtained after stent deployment in the blood pooled below the inflated protection balloon. The samples were centrifuged and evaluated for plaque debris with the use of light microscopy. The debris release was quantitatively estimated by dividing the total volume of debris obtained by the mean debris size. Five patients without endovascular procedure were used as a control group. RESULTS: The 2 main debris types found were nonrefringent cholesterol crystals (4 to 389 microm; 115 to 8697 in number) and lipoid masses (7 to 600 microm; 341 to 34 000 in number). There was a statistically significant difference compared with the samples obtained in the control group (P:=0.017). CONCLUSIONS: Blood samples collected during stent implantation procedures contain a large quantity of atheromatous plaque debris. This emphasizes the role of distal protection techniques in avoiding migration of this plaque material into the cerebral circulation.

Angioplasty, Balloon↗
PubMed2000

Effects of acute and chronic treatment with fluoxetine on regional glucose cerebral metabolism in rats: implications for clinical therapies.

The wide therapeutic spectrum of fluoxetine (e.g., antidepressant, antipanic, antiphobic, antiobsessive, analgesic, antimigraine) requires long-term administration and adaptive changes. To test whether adaptation involves the serotonin (5-HT) transporters, we measured the effects of fluoxetine on the regional cerebral metabolic rate for glucose (rCMRglc) in control rats or in rats pretreated for 2 weeks with fluoxetine (8 mg/kg, i.p., daily, 2 days wash out); rCMRglc was measured in 56 brain regions, using the quantitative [14C]deoxyglucose technique, at 30 min after i.p. administration of fluoxetine 0.4, 4 or 40 mg/kg, i.p., to non-pretreated rats or fluoxetine 4 mg/kg to pretreated rats. In non-pretreated rats, fluoxetine reduced rCMRglc in a dose-dependent fashion in 4 (7%, mean decrease 11%), 28 (50%, mean decrease 23%) and 37 (66%, mean decrease 32%) brain regions. In chronic fluoxetine-pretreated rats, fluoxetine decreased rCMRglc to a substantially lesser degree (eight regions, 14%; mean decrease, 10%). Subcortical brain regions (i.e., hypothalamic paraventricular, locus coeruleus and basal ganglia nuclei) that mediate the physiological responses to stress were very sensitive to fluoxetine acutely and subsensitive after chronic treatment. As kinetic tolerance to fluoxetine does not occur during chronic administration, the diminished rCMRglc responsivity to fluoxetine reflects dynamic, adaptive tolerance of 5-HT transporters and, consequently, increased synaptic 5-HT concentrations; the findings suggest that fluoxetine may be therapeutic by increasing the 5-HT-negative modulation upon areas that drive the abnormally hyperactive responses to stress found in several neuropsychiatric conditions.

Animals↗
PubMed1999

Cortical regions contributing to the anterior commissure in man.

The human anterior commissure is believed, by extrapolation from data obtained in macaque monkeys, to convey axons from the temporal and orbitofrontal cortex. Reports of interhemispheric transfer and sexual dimorphism related to the anterior commissure, however, make more precise data on the human anterior commissure desirable. We investigated the connectivity of the human anterior commissure in six adults (male and female) that had circumscribed hemispheric lesions in temporal, frontal, parietal or occipital cortices or in infrapallidal white matter using the Nauta for anterogradely degenerating axons. Axons originating in the inferior part of temporal or occipital lobes, occipital convexity and possibly central fissure and prefrontal convexity were found to cross the midsagittal plane in the anterior commissure. The largest contingent of commissural axons originated in the inferior part of the temporal lobe; it displayed a roughly topographic organization, preferentially running through the inferior part of the commissure. The inferior temporal contingent seemed to reach homotopic and heterotopic targets in the opposite hemisphere. Among the latter were the amygdala and possibly the orbitofrontal cortex. The present data suggest that the human anterior commissure conveys axons from much larger territories than expected from work on non-human primates. Similarly to the human and non-human primate corpus callosum, the anterior commissure is roughly topographically organized and participates in heterotopic connectivity.

Aged↗
PubMed1999

Evaluation of trimethoprim and sulphamethoxazole as monotherapy or in combination in the management of toxoplasmosis in murine models.

The combination of trimethoprim (TMP) and sulphamethoxazole (SMX) is commonly used for the prevention of cerebral toxoplasmosis although there is no firm experimental basis to support this regimen. We used strain RH tachyzoites for challenge in the acute murine model of toxoplasmosis and found that TMP administered as a single agent, failed to eradicate toxoplasma even at the highest dose (70 mg/kg per day). SMX alone at 600 mg/kg per day, protected ten out of ten mice, although inoculation of brain from surviving animals to naive mice resulted in the development of an encephalitis. When combined, TMP (60 mg/kg per day) and SMX (300 mg/kg per day) protected ten out of ten mice and gave a 'cure' in four out of four mice. In the chronic cystogenic murine models, the combination TMP plus SMX administered from day 5 for 15 days or from day 28 for 288 days, gave protection and even apparent toxoplasmal eradication ('cure') at the highest dosing (60/300 mg/kg per day). However, microscopic severe encephalitis was found in mice classified as 'cured' after reinoculation. This result makes the interpretation of 'cure' very difficult. In conclusion TMP and SMX act synergistically, SMX being the more active arm of the combination. The combination was efficient in preventing the lethal development of chronic toxoplasma encephalitis, but did not guarantee complete recovery.

Animals↗
PubMed1999

Pediatric medulloblastoma: prognostic value of p53, bcl-2, Mib-1, and microvessel density.

The aim of this study was to retrospectively assess the prognostic value of p53 and bcl-2 protein expression, cell proliferation index (Mib-1 index), and tumor microvessel density (factor VIII-related antigen) in pediatric medulloblastoma patients. Tumor specimens of 55 patients (age 2-18 years) with medulloblastoma treated with a curative intent between 1972 and 1991 were studied. Slides of paraffin embedded tissue were stained with monoclonal antibodies (mAb) and examined under high power light microscopy for the presence of immunoreactivity. Microvessel density was scored both in the area of most intense staining ('Angio-max') and in 3 additional randomly selected areas. The sum of these 4 scores was termed 'Angio-total'. 'Angio-max' and 'Angio-total' were evaluated separately by two independent investigators to assess reproducibility. None of the parameters studied, i.e. p53 or bcl-2 expression, Mib-1 index or microvessel density scores were associated with patient survival. Microvessel scores between observers were significantly but weakly correlated, with correlation coefficients (r) < 0.5 for both 'Angio-max' and 'Angio-total'. Leptomeningeal spread at diagnosis was the only independent factor associated with a poor survival (p = 0.003). There was no association of leptomeningeal metastasis with any of the biological markers tested in this study.

Adolescent↗
PubMed1998

Needle muscle biopsy in the investigation of neuromuscular disorders.

We have evaluated needle muscle biopsies in 220 patients with various neuromuscular disorders, using a method developed previously at Tuft's University. The method uses a 14-gauge needle propelled by an automatic device. An average of 3.5 samplings were taken per patient. Muscle samples were used for histological and molecular genetic analysis, and for the isolation of muscle satellite cells for in vitro cultures. The biopsy is well tolerated by the patients who never declined multiple samplings. Complications were few and minor, with no sequelae. In most cases the small size of the muscle specimen (ca. 15 mg per sampling) was sufficient to perform the various procedures and to yield a diagnosis. Specimens were considered insufficient for histological results in 9 patients (4%), due to technical artifacts or insufficient material. We now routinely use this method, which has several advantages over the surgical technique for most muscle biopsies.

Adolescent↗
PubMed1998

Epidermoid cyst of the skull with nonpulsatile tinnitus.

We report an intradiploic epidermoid cyst of the skull responsible for transverse sinus compression and presenting with nonpulsatile tinnitus. Plain films and CT both demonstrated the tumour. Cerebral angiography showed best the degree of narrowing of the right transverse sinus, accompanied with turbulent flow probably leading to tinnitus. MRI demonstrated accurately both the tumour and the dural sinus compression. The tumour was totally removed, cranioplasty was performed, and the patient was discharged free of symptoms.

Adult↗
PubMed1998

Regional cerebral blood flow changes in patients with cirrhosis assessed with 99mTc-HM-PAO single-photon emission computed tomography: effect of liver transplantation.

BACKGROUND/AIMS: Previous studies showed contrasting results with regard to alterations of regional cerebral blood flow/metabolism in subjects with liver cirrhosis. The aim of the study was to extend these findings in a larger series of patients. In addition, we wanted to determine whether such alterations are reversed by successful liver transplantation. METHODS: The study group comprised 23 patients with liver cirrhosis and 13 normal controls. At entry to the study, all subjects underwent a complete neurological examination, EEG recordings and SPECT scanning. The severity of liver disease was determined according to the Child-Pugh score. Fourteen patients underwent a second SPECT examination 1 year after liver transplantation. RESULTS: Significant rCBF reductions, ranging from 6% to 7%, were found in the majority of the cortical regions of the whole group of patients with cirrhosis, as compared to controls. These reductions were more diffuse in patients with alcoholic liver disease, comprising almost all the assayed regions. Liver transplantation normalized cortical rCBF deficits so that postoperative perfusion indexes were superimposable on control values. However, the frontal cortex remained significantly more impaired in patients with alcoholic cirrhosis than in those with non-alcoholic cirrhosis. The differences in frontal rCBF between the two groups of patients ranged from 6 to 11%. CONCLUSIONS: Liver cirrhosis was associated with rCBF defects that depend upon the etiology of liver disease and that subsided after successful liver transplantation. The frontal defects in alcoholic cirrhosis either before or after surgery may imply a neurotoxic, possibly irreversible, action of ethanol.

Adult↗
PubMed1998

Well differentiated cerebellar tissue within a mature cystic teratoma.

We describe the case of a 27 year-old woman presenting with acute abdominal pain due to torsion of a right ovarian cyst. Histopathological examination of the excised lesion revealed a mature cystic ovarian teratoma consisting primarily of a highly organized cerebellar component, an exceedingly rare finding. The possibility of a malignant neuroepithelial tumor arising from immature precursor cells within this neural tissue justifies complete excision of such lesions.

Adult↗
PubMed1998

Etoposide-carboplatin association as 'emergency' up-front chemotherapy in a case of life-threatening adult medulloblastoma.

Medulloblastoma is a rare tumor in the adult population. Current therapies include surgery and irradiation. Unlike in children, chemotherapy is not commonly used, and its potential has poorly been investigated to date. We report the case of an adult patient with disseminated medulloblastoma and fulminant neurological deterioration, precluding craniospinal irradiation. Emergency chemotherapy consisting of carboplatin (400 mg/m2) and etoposide (500 mg/m2) with intrathecal (i.t.) administration of cytosar and hydrocortisone was initiated. Impressive clinical response was achieved after the first cycle of chemotherapy, with the complete disappearance of the lesions detected by MRI. After 3 courses of chemotherapy, the patient underwent craniospinal irradiation (36 Gy to the entire neuraxis and 54 Gy to the posterior fossa). Two years after surgery, the patient was well, with complete clinical recovery, and a new MRI confirmed the disappearance of the lesions. Given the dramatic efficacy of the etoposide-carboplatin association (combined with i.t. cytosar), this regimen has to be considered in an emergency setting and seems to be a very attractive candidate to be investigated as first line therapy for poor risk medulloblastoma in adults.

Adult↗
PubMed1998

An unusual case of Creutzfeldt-Jakob disease.

A patient with histopathologically verified sporadic Creutzfeldt-Jakob disease (CJD) presented initially with diplopia, sleep disturbances, and L-dopa-responsive parkinsonism. After more than a year of slow progression, he did not become demented, and failed to fulfill the clinical criteria for possible CJD. No clinical examinations currently proposed to detect CJD showed the disease. CJD should be in the differential diagnosis of "parkinson plus" syndromes until a different etiology has been found or a histopathologic examination performed.

Creutzfeldt-Jakob Syndrome↗
PubMed1997

The effects of propofol on cerebral high energy metabolites, lactate, and glucose in normoxic and severely hypoxic rats.

Study was performed in Fischer-344 rats to test the effects of the intravenous anesthetic propofol on cerebral content of high-energy metabolites, glucose, and lactate in normoxic and severely hypoxic rats. General and local anesthetics (isoflurane, N(2)O 70%, pancuronium bromide, bupivacaine hydrochloride) were used for surgery (tracheostomy, femoral artery and vein cannulation, skull exposure, ligature of right-sided carotid and EEG needle electrodes only in rats devoted to the hypoxia study). For normoxia study, four groups of 7 rats each were treated for 60 min as it follows: the control group with N(2)O plus propofol vehicle and the other three with propofol 12.5, 25, or 50 mg x kg(-1) x h(-1) respectively. For the hypoxia-study five groups of 7 rats each were planned to have two control (one normoxic) and three propofol-treated groups, drug treatments being the above indicated and of 80 min. During the last 20 min Pa(O(2)) was lowered to 15-20 mmHg. Pa(CO(2)) was maintained between 35-40 mmHg, rectal temperature at 37 degrees C, MABP near to 100 mmHg and pH on the basal values during the whole procedure. Then brains were frozen in vivo, and cortical tissue was excised and analyzed for labile metabolites using fluorometric techniques. Propofol, at all the doses tested, did not alter the concentrations of adenine nucleotides, phosphocreatine, lactate, pyruvate, or glucose in normoxic rats. In rat brain, hypoxia did not produce significant changes in the concentrations of adenine nucleotides. PCr concentration was decreased both in the ligated and unligated side, and lactate levels exceeded 21 and 18 micromol/g in the right and left cortices, respectively. While the lowest dose of propofol was ineffective in preventing PCr decrease and lactate increase, both 25 and 50 mg x kg(-1) x h(-1) significantly reduced those adverse effects of hypoxia.

Adenine Nucleotides↗
PubMed1997

Randomised, double-blind, placebo-controlled study of pivagabine in neurasthenia.

One hundred and eighteen patients with neurasthenia, as defined by ICD 10 (International Classification of Diseases), participated in a randomised, double-blind, placebo-controlled trial of pivagabine (4-[(2,2-dimethyl-1-oxopropyl)amino]butanoic acid, CAS 69542-93-4, Tonerg). Pivagabine 1800 mg/d was administered orally for four weeks. At the end of the trial, active medication was significantly superior to placebo on the Clinical Global Impression (CGI) improvement of illness scale. In addition, pivagabine treatment reduced the physical and mental fatigability of patients, and increased their sense of well-being.

Adolescent↗