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V Silvani

Publications and source records attributed to V Silvani.

At least 19 recordsLinked to original sources
PubMed1991

A study on the biological behavior of human brain tumors. Part II: Steroid receptors and arachidonic acid metabolism.

The significance of steroid receptors (SR) in human brain tumors is presently a field of intense investigation in order to clarify some aspects of the biological behavior of these neoplasms. We studied the relationship between the presence of steroid receptors and the production of metabolites of the arachidonic acid cascade which have been reported to have a role in the biological behavior of some human tumors. We found that some metabolites of arachidonic acid are produced in different amounts in brain tumors which either did or did not express some steroid receptors. In particular the PGE2 were higher in estrogen receptors (ER) positive meningiomas than in ER negative ones and 6-keto-PGF1 alpha, the stable metabolite of prostacyclin, is significantly higher in androgen receptors (AR) negative meningiomas than in AR positive ones. In neuroepithelial tumors the glucocorticoid receptors (GR) positive cases synthesized more TxB2 and less PGE2 than the GR negative ones. Our data seem to suggest that some correlations exist between the presence of some steroid receptors and arachidonic acid metabolite production.

Arachidonic Acid↗
PubMed1991

Concentrations of VP16 and VM26 in human brain tumors.

VP16 and VM26 were determined by high pressure liquid chromatography in intracerebral tumors, adjacent normal brain tissue, plasma and CSF samples from 24 patients given the two drugs before surgical resection of the tumor. The drugs were administered at doses of 100-150 mg/m2 as a 1-hour i.v. infusion, between 1.5 and 12 hours before surgery. Concentrations of VP16 ranged between 1.05 and 3.28 micrograms/g in tumors in the series of patients who received the drug 1.5-3 hours before surgery and between less than 0.05 and 1.12 micrograms/g in four patients who received the drug 9-13 hours before surgery. Tumor concentrations of VM26 also varied, ranging from less than 0.05 to 1.68 micrograms/g between 1.5 and 12 hours before surgery. VP16 and VM26 in the apparently normal brain tissue surrounding the tumor were low or undetectable except in one patient who had received radiotherapy, in whom we found 3.1 micrograms/g.

Adult↗
PubMed1990

Experimental isobaric subarachnoid hemorrhage: regional mitochondrial function during the acute and late phase.

Patients treated for aneurysmal subarachnoid hemorrhage show, in the long-term follow up, an elevated rate of cognitive disturbances that are mainly related to the impact of the initial bleeding: the neurotoxic effects of blood deposition in subarachnoidal spaces may result in a diffuse encephalopathy, but the intrinsic mechanism and the biochemical correlates are not known. In the present study we have evaluated mitochondrial function after experimental induction of subarachnoid hemorrhage. Mitochondrial function was evaluated in four different rat brain areas (frontal cortex, occipital cortex, hippocampus, and brain stem) after experimental isobaric subarachnoid hemorrhage in rats. Subarachnoid hemorrhage was induced by injecting 0.07 mL of arterial autologous blood into the cisterna magna. Intracranial pressure did not significantly increase. The nonsynaptic mitochondrial fraction was isolated from different rat brain areas, and the maximal rate of enzymatic reactions of some key enzymatic activities related to the Krebs cycle [nicotinamide adenine dinucleotide (oxidized form) (NAD+)-isocitrate dehydrogenase, citrate synthase, and succinate dehydrogenase] and of the electron transfer chain (cytochrome oxidase) were evaluated. The nonsynaptic mitochondrial fraction was utilized also to check parameters related to the mitochondrial respiration: state 3, state 4, uncoupled state, respiratory control ratio, and adenosine 5'-diphosphate/oxygen ratio. The biochemical parameters were measured at 1 and 72 hours after the subarachnoidal injection of blood. Subarachnoid hemorrhage did not affect the mitochondrial enzymatic activities both at 1 and 72 hours, while the mitochondrial enzymatic activities parameters were significantly affected: in particular, a significant decrease of respiratory control ratio in all tested brain areas was demonstrated. The increased mitochondrial vulnerability in the delayed phases could be one of the biochemical correlates of post-hemorrhagic encephalopathy.

Analysis of Variance↗
PubMed1989

Experimental subarachnoid hemorrhage. Lipid peroxidation and Na+,K(+)-ATPase in different rat brain areas.

Subarachnoid hemorrhage (SAH) was produced in Sprague Dawley rats by injection of 0.30 mL of autologous arterial blood into the cisterna magna. Tissue lipid peroxide, quantified as thiobarbituric acid reactive material (TBAR), and Na+,K(+)-ATPase activity were assayed in three different rat brain areas (cerebral cortex, hippocampus, and brain stem) of sham-operated rats and in four hemorrhagic rat groups at 30 min, 1 h, 6 h, and 2 d after SAH. Na+,K(+)-ATPase activity decreased in the cerebral cortex at 30 min, 1 h, and 6 h and in the brain stem at 1 h after SAH induction, whereas enzymatic activity was unchanged in the hippocampus. There was no evident difference in lipid peroxide content between sham-operated animals and hemorrhagic animals. These results indicate that little modifications in lipid peroxidative process (as expressed in TBAR) are not responsible for changes in the ATPase activity.

Animals↗
PubMed1989

Phosphatases and cathepsin D activities after vasogenic oedema: an experimental study.

The role of two phosphatases (acid and alkaline phosphatase) and a lysosomal aspartyl endopeptidase (cathepsin D) in producing rat brain oedema was studied in 3 different rat cerebral areas (i.e. frontal cortex, hippocampus and striatum) at 1, 2 and 3 d after vasogenic brain oedema induction. The percentage of water content in the frontal cortex increased immediately, 1 d after oedema induction and remained high for 2 and 3 d after oedema induction. In the hippocampus and the striatum the water content only increases 3 d after oedema induction. In the oedematous hemisphere (right), when compared to the contralateral hemisphere (left), the acid phosphatase activity decreases in the hippocampus, while the alkaline phosphatase increases in the frontal cortex and striatum; cathepsin D increases only in the striatum. The changes caused by the enzymatic activities were significant only 2 and 3 d after oedema induction. The results of this study show that: (i) the vasogenic oedema induced in experimental conditions was not sufficient to cause a massive liberation of lysosomal enzymes and (ii) brain areas adjacent (below) to the site of the experimental oedematous lesion (frontal cortex) were influenced by oedema induction.

Acid Phosphatase↗
PubMed1988

Cell kinetics aspects of human malignant neuroepithelial tumors: a follow-up study.

The prognostic value of proliferative activity and DNA distribution (ploidy), determined by flow cytometry (FCM), was evaluated in 38 cases of human malignant neuroepithelial tumors. No statistically significant correlation was found between flow cytometric data and clinical outcome. In particular, there was no significant difference between mean survival in cases with percentage of cells in S-phase lower and higher than 5%, respectively. In 21 cases with unimodal DNA distribution, the mean survival was 11.7 months; in 17 cases with bimodal DNA distribution, the mean survival was 12.5 months. The difference was not statistically significant. In our experience, proliferative activity and ploidy do not correlate well with the clinical course and survival of patients with malignant neuroepithelial tumors. However, application of FCM may provide, aside from histopathologic examination, additional biologic information that may be valuable in understanding the variation observed in the course of individual patients.

Adult↗
PubMed1988

Effect of nimodipine on mitochondrial respiration in different rat brain areas after subarachnoid haemorrhage.

The mitochondrial respiration was evaluated in three different rat brain areas (cerebral cortex, hippocampus and brain stem) after experimental subarachnoid haemorrhage (SAH). The haemorrhage was induced by injecting 0.35 ml of autologous arterial blood into cisterna magna. Intravenous administration of Nimodipine (2 micrograms/kg/min for 30 minutes) was started immediately after the haemorrhage induction. At the set time (1 hour after SAH procedure), animals were sacrificed and non-synaptic mitochondria from the above mentioned areas were isolated. The following respiratory parameters were evaluated utilizing glutamate plus malate and succinate plus rotenone as substrates: state 3, state 4, uncoupled state, respiratory control ratio (RCR) and ADP/O ratio. SAH significantly influences respiratory parameters, mainly RCR; the cerebral cortex and brain stem seem to be more sensitive during the acute phase of vasospasm which follows SAH procedure. Nimodipine treatment significantly ameliorates mitochondrial respiratory conditions.

Animals↗
PubMed1988

Trazodone for deafferentation pain. Comparison with amitriptyline.

We report a clinical multicentre experience with antidepressant agents (trazodone and amitriptyline) in the treatment of chronic pain due to deafferentation. Forty five patients were admitted to the study; most of them with oncological peripheral nerve lesions. Almost all of them were already being treated with NSAID in association with weak or strong opioids. A random double blind study was performed: 23 patients were treated with trazodone, 22 with amitriptyline. In the assessment of results, pain intensity, hours of sleep, hours standing and lying, side effects, mood, anxiety and weakness were all taken into consideration. The therapeutic analgesic efficacy of the two drugs proved to be similar.

Adult↗
PubMed1988

Bioenergetics of different brain areas after experimental subarachnoid hemorrhage in rats.

We studied energy metabolism after experimental subarachnoid hemorrhage in rats. Four different cerebral areas were tested: frontal cortex, occipital cortex, hippocampus, and brainstem. Vmax of the following enzymatic activities was evaluated: in the homogenate: hexokinase, phosphofructokinase, and lactate dehydrogenase for the glycolytic pathway, and glucose-6-phosphate dehydrogenase for the hexose monophosphate shunt; in the purified nonsynaptic mitochondria: NAD+-isocitrate dehydrogenase, citrate synthase, and succinate dehydrogenase for the Krebs cycle, and cytochrome oxidase for the electron transfer chain. We also evaluated some parameters related to the respiration of nonsynaptic mitochondria (State 3, State 4, uncoupled state, respiratory control ratio, and ADP:O ratio). Subarachnoid hemorrhage did not significantly affect Vmax of the enzymatic activities related to anaerobic and aerobic metabolism; however, mitochondrial respiration was affected, particularly in the presence of NADH-producing substrates (glutamate + malate).

Adenosine Diphosphate↗
PubMed1988

CSF leukotriene C4 following subarachnoid hemorrhage.

Leukotrienes derive from arachidonic acid metabolism via the lipoxygenase pathway and modulate several cellular events. In the central nervous system, leukotrienes are mainly synthesized in the gray matter and in vascular tissues. Their production is enhanced in ischemic conditions and in experimental subarachnoid hemorrhage (SAH). Previous studies have indicated the ability of the leukotrienes C4 and D4 to constrict arterial vessels in vivo and in vitro and have suggested their involvement in the pathogenesis of cerebral arterial spasm. In the present study, the authors measured lumbar and cisternal cerebrospinal fluid (CSF) levels of leukotriene C4 in 48 patients who had suffered aneurysmal SAH. In 12 of the cases, symptomatic and radiological spasm was evident. The mean lumbar CSF level of immunoreactive-like activity of leukotriene C4 (i-LTC4) was significantly higher (p less than 0.005) than in control cases, while the cisternal CSF level was higher than the lumbar mean concentration (p less than 0.005). Patients presenting with vasospasm had significantly higher levels of i-LTC4 compared to patients without symptomatic vasospasm. This is the first report concerning monitoring of i-LTC4 levels in the CSF after SAH. The results of this study suggest that: 1) metabolism of arachidonic acid via the lipoxygenase pathway is enhanced after SAH; 2) the higher cisternal CSF levels of i-LTC4 may be part of the biological response in the perianeurysmal subarachnoid cisterns after the hemorrhage; and 3) the higher CSF levels of i-LTC4 in patients presenting with vasospasm suggest that a relationship exists between this compound and arterial spasm and/or reflect the development of cerebral ischemic damage.

Cisterna Magna↗
PubMed1987

Association of BK virus with human brain tumors and tumors of pancreatic islets.

BK virus (BKV) DNA was detected by Southern blot hybridization in 19 out of 74 (25.6%) human brain tumors and in 4 out of 9 (44.4%) human tumors of pancreatic islets. BKV DNA was free, in an episomal state and generally in a low copy number (0.2 to 2 genome equivalents per cell). Only occasional tumors contained 10 to 20 genome copies per cell. Viral DNA sequences integrated into cellular DNA were not detected. A number of tumors expressed BKV-specific RNA and T antigen. By transfection of total tumor DNA into human embryonic fibroblasts, viruses with the biological and antigenic properties of BKV were rescued from 6 brain tumors and from 2 tumors of pancreatic islets. Restriction endonuclease mapping of the genomes of the rescued viruses showed that they differ from wild-type BKV. They are all similar to each other and to BKV-IR, a virus previously rescued from a human tumor of pancreatic islets, suggesting the possible association of a BKV variant with specific types of human neoplasms. The significance of the relationship of these BKV variants to human tumors and their possible etiologic role in human oncogenesis are discussed.

Adenoma, Islet Cell↗
PubMed1987

Arachidonic acid metabolic profiles in human meningiomas and gliomas.

We determined arachidonic acid (AA) cyclooxygenase metabolic profiles in specimens of human intracranial tumors (gliomas and meningiomas) and, when available, normal brain tissue. Samples were collected at surgery and immediately frozen in liquid nitrogen. The five stable metabolites of AA (PGE2, PGD2, PGF2 alpha, 6-keto-PGF1 alpha and TXB2) were measured by high-resolution gas chromatography-mass spectrometry after ex vivo metabolism of endogenous AA by tissue homogenates. The absolute amounts of AA metabolites varied widely between samples, though meningiomas and gliomas showed characteristic profiles. Compared to the slow-growing benign meningiomas, the rapidly-growing infiltrating gliomas had higher synthesis of TXA2 (reported as a procancer metabolite) and lower synthesis of PGD2 and PGI2 (reported as anticancer metabolites). A higher overall synthesis capacity, preferentially toward TXA2, was found in glioblastomas than in non-pathological brain tissue.

Arachidonic Acid↗
PubMed1987

Cisternal and lumbar CSF levels of arachidonate metabolites after subarachnoid haemorrhage: an assessment of the biochemical hypothesis of vasospasm.

Several naturally occurring compounds have been identified in human cerebrospinal fluid (CSF) after subarachnoid haemorrhage (SAH) as possible vasoactive agents involved in the biochemical mechanism of vasospasm. The authors have measured, in 30 patients admitted for SAH, CSF concentrations of two arachidonic acid metabolites. Prostacyclin and Prostaglandin D2, as representative of vasodilator and vasoconstrictor compounds. CSF samples were made available by lumbar punctures and intraoperative cisternal punctures. Nine patients presented with symptomatic vasospasm: lumbar CSF Prostaglandin D2 levels are significantly higher than in patients without vasospasm. The Cisternal Prostaglandin D2 level is significantly higher than the lumbar CSF concentration; CSF Prostacyclin levels do not significantly differ in the two groups of patients. These data suggest the presence of an imbalanced biochemical situation responsible for promoting vasospasm. The evaluation of cisternal levels of arachidonate metabolites support the hypothesis of the clotting phenomenon around the ruptured aneurysm wall as an important predictive pattern of vasospasm onset after SAH, as shown in computed tomography.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Antidepressants for cancer pain and other painful syndromes with deafferentation component: comparison of amitriptyline and trazodone.

The Authors report a clinical multicentre experience with antidepressant agents (trazodone and amitriptyline) in the treatment of chronic cancer pain with deafferentation component. Forty-five patients were admitted to the study: 27 with oncological peripheral nerve lesions, 6 with post herpetic neuralgias, 10 with not oncological nerve lesions, 2 with central nervous lesions. Almost all of them were already being treated with NSAID associated with weak or strong opioids. A random double blind study was performed: 23 patients were treated with trazodone, 22 with amitriptyline. In the assessment of results, pain intensity, hours of sleep, hours standing and lying, side effects, mood, anxiety, weakness were all taken into consideration. The therapeutic analgesic efficacy of the two drugs proved to be similar.

Adult↗
PubMed1987

Nitrosourea derivatives-induced pulmonary toxicity in patients treated for malignant brain tumors. Early subclinical detection and its prevention.

Nitrosourea derivatives, such as BCNU and CCNU, are considered useful chemotherapeutic agents in malignant brain tumors combined therapy. Pulmonary toxicity is one of the major side effects demonstrated both in experimental animal models and in human autoptic findings. Pulmonary fibrosis is the end point of progressive functional disorder of respiratory mechanism and alveolo-capillary gas exchanges. Authors present the results of a randomized, double-blind trial of 40 patients previously treated with surgery and radiotherapy and who subsequently underwent BCNU therapy for primary intracranial glioma. Patients underwent functional respiratory examinations at each chemotherapy course interval. Twenty patients received ambroxol (120 mg/day) for 40 days after chemotherapy course. Control patients received placebo with the same schedule and showed a significant reduction of pulmonary functional parameters (DLCO, MMEF, MEF 25%), whereas in the treated group there is no significant variation of these functional parameters. The mechanism of ambroxol is commonly related to the surfactant synthesis enhancement and to the action on bronchiolar pathways.

Adult↗
PubMed1987

Vertebral osteomyelitis with chronic cervical extradural abscess in a heroin addict.

Chronic extradural abscess at C5-C6 level due to vertebral osteomyelitis is reported. The patient, a 26-year-old woman who had taken heroin intravenously for four years, developed progressive tetraparesis. Blood cultures and, at operation, the culture of the abscess drainage, grew Staphylococcus aureus. High resolution CT scan allowed for prompt diagnosis. Decompressive laminectomy and complete removal of the extradural mass were performed immediately, followed by multiple subtotal somatectomy (MSS) in order to obtain anterior decompression and mechanical reconstruction of the cervical column. The pathogenetic, diagnostic and surgical problems of spinal extradural abscess are discussed. Multiple subtotal somatectomy and its indication are described.

Abscess↗
PubMed1987

Ploidy and proliferative activity of human brain tumors. A flow cytofluorometric study.

Ploidy and proliferative characteristics were estimated by flow cytometry of the nuclear DNA content of 92 human brain tumors. Samples were frozen at -20 degrees C immediately after surgery and single cell suspensions were obtained with a mechanical dissociation technique. Propidium iodide was employed for nuclear DNA staining. Human normal brain tissue was used as internal diploid reference standard. 86% of benign tumors had unimodal DNA distribution with a DNA index (DNA I = modal channel of the G0/1 peak of the studied population/modal channel of the G0/1 peak of the normal brain) usually within the diploid or near-diploid range. 14.0% had aneuploidy, with an additional cell peak having a median DNA I of 1.60. Among malignant tumors, these figures were 61.2 and 38.8% (p less than 0.001). The percentage of S phase cells was higher in malignant (median = 3.6) than in benign tumors (median = 2.0, p less than 0.01), without correlation to histological tumor subtype. Flow cytometry appears to be a useful method for evaluating differences in DNA distribution in tumors of the central nervous system.

Adolescent↗