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P Severi

Publications and source records attributed to P Severi.

17 recordsLinked to original sources
PubMed1999

Pre-operative plasma levels of soluble fibrin polymers correlate with the development of deep vein thrombosis after elective neurosurgery.

The role of blood tests in identifying patients at high risk for post-operative venous thromboembolism is undefined. The aim of this study was to evaluate the correlation between pre-operative plasma levels of soluble fibrin polymers (SFP), as determined by a recently developed enzyme-linked immunosorbent assay (ELISA) assay (TpP), and the incidence of deep vein thrombosis (DVT) after elective neurosurgery. Blood samples for SFP assay were withdrawn on the day before surgery from 157 consecutive patients undergoing elective neurosurgery for brain or spinal tumour. Patients were randomized to subcutaneous enoxaparin (40 mg once daily) or placebo given for at least 7 days. All patients wore compression stockings. DVT was assessed by bilateral venography, performed on day 8 +/- 1. Thirty-four patients (21.7%) were found to have a DVT, proximal in 11 (7%) and isolated distal in 23. Patients with and without DVT had a plasma pre-operative SFP levels of 6.2 +/- 4.6 and 1.9 +/- 1.5 mg/ml respectively (mean +/- SD) (P < 0.001). SFP levels in patients with proximal and isolated distal DVT were 7.6 +/- 5.1 and 5.5 +/- 4.4 microg/ml, respectively (P = 0.22). SFP cut-off levels categorized patients into three classes of DVT incidence. The incidence of DVT was 7.4% (6 of 81) for SFP levels < 2 microg/ml, 20.4% (11 of 54) for levels between 2 and 4.5 microg/ml, and 77.3% (17 of 22) for levels > 4.5 microg/ml (P= 0.001, Cochran-Mantel-Haenszel test). We conclude that pre-operative SFP levels correlate with post-operative DVT in elective neurosurgery patients. Further studies are required to define whether pre-operative SFP measurement could be useful in patient management.

Adult↗
PubMed1998

Enoxaparin plus compression stockings compared with compression stockings alone in the prevention of venous thromboembolism after elective neurosurgery.

BACKGROUND: Compression stockings are recommended for prophylaxis against venous thromboembolism in patients undergoing neurosurgery, but anticoagulant agents have not gained wide acceptance because of concern about intracranial bleeding. METHODS: In a multicenter, randomized, double-blind trial, we assessed the efficacy and safety of enoxaparin in conjunction with the use of compression stockings in the prevention of venous thromboembolism in patients undergoing elective neurosurgery. Enoxaparin (40 mg once daily) or placebo was given subcutaneously for not less than seven days beginning within 24 hours after the completion of surgery. The primary end point was symptomatic, objectively confirmed venous thromboembolism or deep-vein thrombosis assessed by bilateral venography, which was performed in all patients on day 8+/-1. Bleeding side effects were carefully assessed. RESULTS: Among the 307 patients assigned to treatment groups, 129 of the 154 patients receiving placebo (84 percent) and 130 of the 153 patients receiving enoxaparin (85 percent) had venographic studies adequate for analysis. An additional patient in the placebo group died before venography of autopsy-confirmed pulmonary embolism. In this analysis, 42 patients given placebo (32 percent) and 22 patients given enoxaparin (17 percent) had deep-vein thrombosis (relative risk in the enoxaparin group, 0.52; 95 percent confidence interval, 0.33 to 0.82; P=0.004). The rates of proximal deep-vein thrombosis were 13 percent in patients receiving placebo and 5 percent in patients receiving enoxaparin (relative risk in the enoxaparin group, 0.41; 95 percent confidence interval, 0.17 to 0.95; P=0.04). Two patients in the placebo group died of autopsy-confirmed pulmonary embolism on days 9 and 16. Major bleeding occurred in four patients receiving placebo (intracranial bleeding in all four) and four patients (intracranial bleeding in three) receiving enoxaparin (3 percent of each group). CONCLUSIONS: Enoxaparin combined with compression stockings is more effective than compression stockings alone for the prevention of venous thromboembolism after elective neurosurgery and does not cause excessive bleeding.

Adult↗
PubMed1997

Pharmacologically distinct GABAB receptors that mediate inhibition of GABA and glutamate release in human neocortex.

1. The release of endogenous gamma-aminobutyric acid (GABA) and glutamic acid in the human brain has been investigated in synaptosomal preparations from fresh neocortical samples obtained from patients undergoing neurosurgery to reach deeply located tumours. 2. The basal outflows of GABA and glutamate from superfused synaptosomes were largely increased during depolarization with 15 mM KCl. The K(+)-evoked overflows of both amino acids were almost totally dependent on the presence of Ca(2+) in the superfusion medium. 3. The GABAB receptor agonist (-)-baclofen (1, 3 or 10 microM) inhibited the overflows of GABA and glutamate in a concentration-dependent manner. The inhibition caused by 10 microM of the agonist ranged from 45-50%. 5. The effect of three selective GABAB receptor antagonists on the inhibition of the K(+)-evoked GABA and glutamate overflows elicited by 10 microM (-)-baclofen was investigated. Phaclofen antagonized (by about 50% at 100 microM; almost totally at 300 microM) the effect of (-)-baclofen on GABA overflow but did not modify the inhibition of glutamate release. The effect of (-)-baclofen on the K(+)-evoked GABA overflow was unaffected by 3-amino-propyl (diethoxymethyl)phosphinic acid (CGP 35348; 10 or 100 microM); however, CGP 35348 (10 or 100 microM) antagonized (-)-baclofen (complete blockade at 100 microM) at the heteroreceptors on glutamatergic terminals. Finally, [3-[[(3,4-dichlorophenyl) methyl]amino]propyl] (diethoxymethyl) phosphinic aid (CGP 52432), 1 microM, blocked the GABAB autoreceptor, but was ineffective at the heteroreceptors. The selectivity of CGP 52423 was lost at 30 microM, as the compound, at this concentration, inhibited completely the (-)-baclofen effect on both GABA and glutamate release. 5. It is concluded that GABA and glutamate release evoked by depolarization of human neocortex nerve terminals can be affected differentially through pharmacologically distinct GABAB receptors.

Aged↗
PubMed1996

Human brain N-methyl-D-aspartate receptors regulating noradrenaline release are positively modulated by HIV-1 coat protein gp120.

OBJECTIVE: To investigate the effect of HIV-1 gp120 on the function of glutamate receptors of the N-methyl-D-aspartate (NMDA) type in the human brain. DESIGN: The monitoring of neurotransmitter release from superfused isolated nerve endings is widely recognized as a technique appropriate for the study of neurotransmitter release and to attribute a precise localization to the site(s) of action of drugs able to modulate release. METHODS: Synaptosomes (pinched-off nerve endings) were prepared from fresh human brain tissue samples removed during neurosurgery, labelled with [3H]-noradrenaline and superfused at a rate of 0.5 ml/min with NMDA in the presence of gp41, gp160, gp120 or the V3 loop, with or without NMDA receptor antagonists. Fractions of superfusate were collected and measured for radioactivity. RESULTS: NMDA elicited a glycine-sensitive release of [3H]-noradrenaline from human brain synaptosomes. HIV-1 gp120 potentiated the NMDA (1 mM)-evoked [3H]-noradrenaline release (maximal effect approximately 110% at 1 nM). The release elicited by NMDA plus gp120 was prevented by the classical NMDA receptor antagonists dizocilpine or 7-chlorokynurenic acid, as well as by memantine. The potentiation by gp120 of the NMDA-evoked [3H]-noradrenaline release was mimicked by gp160 but not by gp41. The effect of gp120 was retained by the V3 loop. Finally, gp120 reversed (1 nM) and surmounted (10nM) the antagonism by 10 microM 7-chlorokynurenate of the NMDA-evoked [3H]-noradrenaline release. CONCLUSION: gp 120 binds directly through the V3 loop at noradrenergic axon terminals in human brain neocortex and may alter the function of presynaptic NMDA receptors mediating regulation of noradrenaline release.

Adult↗
PubMed1996

Human brain somatostatin release from isolated cortical nerve endings and its modulation through GABAB receptors.

UNLABELLED: 1. The release of somatostatin-like immunoreactivity (SRIF-LI) in the human brain was studied in synaptosomal preparations from fresh neocortical specimens obtained from patients undergoing neurosurgery to remove deeply sited tumours. 2. The basal outflow of SRIF-LI from superfused synaptosomes was increased about 3 fold during exposure to a depolarizing medium containing 15 mM KCl. The K(+)-evoked overflow of SRIF-LI was almost totally dependent on the presence of Ca2+ in the superfusion medium. 3. The GABAB receptor agonist, (-)-baclofen (0.3 - 100 microM), inhibited the overflow of SRIF-LI in a concentration-dependent manner (EC50 = 1.84 +/- 0.20 microM; maximal effect: about 50%). The novel GABAB receptor ligand, 3-aminopropyl(difluoromethyl)phosphinic acid (CGP 47656) mimicked (-)-baclofen in inhibiting the SRIF-LI overflow (EC50 = 3.06 +/- 0.52 microM; maximal effect: about 50%), whereas the GABAA receptor agonist, muscimol, was ineffective up to 100 microM. 4. The inhibition by 10 microM (-)-baclofen of the K(+)-evoked SRIF-LI overflow was concentration-dependently prevented by two selective GABAB receptor antagonists, 3-amino-propyl (diethoxymethyl)-phosphinic acid (CGP 35348) (IC50 = 24.40 +/- 2.52 microM) and [3-[[(3,4-dichlorophenyl) methyl]amino]propyl] (diethoxymethyl) phosphinic acid (CGP 52432) (IC50 = 0.06 +/- 0.005 microM). 5. The inhibition of SRIF-LI overflow caused by 10 microM CGP 47656 was abolished by 1 microM CGP 52432. 6. When human synaptosomes were labelled with [3H]-GABA and depolarized in superfusion with 15 mM KCl, the inhibition by 10 microM (-)-baclofen of the depolarization-evoked [3H]-GABA overflow was largely prevented by 10 microM CGP 47656 which therefore behaved as an autoreceptor antagonist. 7. IN CONCLUSION: (a) the characteristics of SRIF-LI release from synaptosomal preparations of human neocortex are compatible with a neuronal origin; (b) the nerve terminals releasing the neuropeptide possess inhibitory receptors of the GABAB type; (c) these receptors differ pharmacologically from the GABAB autoreceptors present on human neocortex nerve terminals since the latter have been shown to be CGP 35348-insensitive but can be blocked by CGP 47656.

Adult↗
PubMed1994

Urokinase thrombolytic therapy of pulmonary embolism in neurosurgically treated patients.

Pulmonary embolism (PE) is a severe complication in neurosurgery. The best treatment of PE is thrombolytic therapy, but the presence of either intracranial neoplasm or recent neurosurgical procedures is considered a major contraindication to this therapy. We have used urokinase thrombolytic therapy in nine of our patients with severe PE that occurred from 7 to 34 days after a neurosurgical operation. All patients survived. No intracranial hemorrhage occurred. We also advocate thrombolytic therapy for severe PE in patients who were recently operated on by neurosurgical procedure.

Adult↗
PubMed1994

Fenfluramine releases serotonin from human brain nerve endings by a dual mechanism.

Fenfluramine is the most widely used anorexigenic drug in humans. In animal experiments d-fenfluramine has been shown to act as a potent releaser of brain serotonin [5-hydroxytryptamine (5-HT)]. Here we have investigated the effects of d-fenfluramine on the release of [3H]5-HT from isolated nerve endings of human neocortex. The drug elicited release of unmetabolized [3H]5-HT, and this effect was concentration dependent. However, the mechanism of release seems to differ profoundly depending on the concentrations of d-fenfluramine used. At 5 microM, the release of [3H]5-HT was blocked by the 5-HT transporter inhibitor fluoxetine and was Ca2+ independent and insensitive to the human autoreceptor 5-HT1D agonist sumatriptan. The release of [3H]5-HT elicited by 0.5 microM d-fenfluramine was similarly blocked by fluoxetine, but it was strongly Ca2+ dependent and sensitive to sumatriptan. It is suggested that, at relatively high concentrations, d-fenfluramine largely diffuses into serotonergic terminals and causes release of 5-HT through the 5-HT carrier working in the inside-outside direction; at relatively low concentrations d-fenfluramine enters the terminals through the 5-HT transporter but elicits release of 5-HT by an exocytotic-like mechanism.

Calcium↗
PubMed1994

Intraventricular pneumocephalus after posterior fossa and CSF shunting surgery. Case report.

The authors report a case of tension intraventricular pneumocephalus developed six months after the removal of an acoustic neuroma and a CSF ventriculoperitoneal shunt procedure due to a concomitant hydrocephalus. A review of the literature show only 19 cases of CSF shunt complicating pneumocephalus. The authors discuss both about the etiology of pneumocephalus and its therapeutic options. In our case we were unable to preoperatively localize the cranial base communication allowing intracranial air antry. The literature show however that eroded or thinned bone areas may be multiple and even diffuse their development depending upon several factors. We suggest in these cases a direct surgical repair through a craniotomy, as reported by others, is not mandatory. According to the etiology of pneumocephalus a temporary extraventricular drainage and the revision of the shunting pressure regimen may represent an effective treatment of this complication.

Cerebrospinal Fluid Shunts↗
PubMed1988

Electrical stimulation of the motor tracts in cervical spondylosis.

Motor action potentials evoked by percutaneous electrical stimulation of the scalp and of the cervical (or lumbar) vertebral region were recorded from the biceps, thenar and tibialis anterior muscles in 30 patients with cervical spondylosis. Twelve normal controls were matched for age and height. Abnormalities of central motor conduction (absence or increased central delay of cortical responses) for at least one muscle were observed in all (but one) the patients with myelopathy alone or combined with radiculopathy. An increase in latency of the responses evoked by cervical stimulation occurred in 40% of patients with radiculopathy or myelo-radiculopathy. Changes of motor conduction occurred even in the absence of abnormalities of somatosensory evoked potentials, while the opposite was never observed. Direct stimulation of the motor tracts may be of value in the functional assessment of the motor pathways in cervical spondylosis.

Adult↗
PubMed1986

Exostosis as a cause of spinal cord compression.

A patient harboring multiple hereditary exostoses with a long-lasting tetraparesis owing to intraspinal osteochondroma is described. The results of surgical treatment were poor in contrast to the results achieved by other previous authors performing decompression of the spinal cord. The related literature is briefly reviewed and conclusions are drawn in favor of computed tomographic examination of the spine of patients with vertebral complaints.

Adult↗
PubMed1985

Spinal carcinomatous metastases. Retrospective study of 67 surgically treated cases.

A series of 67 surgically treated spinal carcinomatous metastases is reviewed in order to establish the role played by surgery in the management of such a disease. The authors compare the results achieved in two groups of patients treated with a different therapeutic approach: either surgery alone or surgery associated with other therapies (mainly radiotherapy). On this basis, although no ideal treatment for spinal epidural metastases can be established, the authors suggest decompressive laminectomy as a first choice approach in the treatment of patients bearing a scarcely radiosensitive spinal metastasis with a rapidly deteriorating motor function.

Combined Modality Therapy↗
PubMed1985

Long-term prognosis of subarachnoid hemorrhages of unknown etiology.

Forty-nine patients who suffered a spontaneous subarachnoid hemorrhage (SAH), and in whom panangiography did not show the cause of the bleeding, were evaluated after a long follow-up (median 8 years). No relationship was found between outcome and antifibrinolytic treatment or blood pressure level. Angiography was repeated in cases with spasm or after rebleeding: one aneurysm was found (7%). The authors suggest that angiography should be repeated in these circumstances. The early mortality was 2%. Late functional capacity was normal in 94% of the patients. No particular restrictions should therefore be recommended.

Adult↗
PubMedDate not supplied

[Primary vertebral hydatidosis. Case report and brief review of the literature].

The authors report a case of primary spinal hydatid cyst. A primary vertebral involvement occurs in about 1% of cases of Echinococcus granulosus infestations. In Italy only 23 cases have been reported to date. The diagnosis of spinal hydatidosis is often available only at the time of surgery because this disease has not specific characteristics as regards other more common causes of spinal cord compression. Surgery is mandatory but the wide bone infiltration makes difficult the radical excision and subsequently there is a high incidence of recurrences.

Echinococcosis↗
PubMedDate not supplied

[Basic behavior and behavior after stimulation of inflammatory cellular response, leukocytary chemotaxis and phagocytosis in aged subjects with depression of cellular immunity].

A larger group of 70--75 years aged subjects was studied by means of various cutaneous tests, by E-rosette formation and by blastogenic response and 18 people showing a depressed cellular immunity were selected. These subjects and a similar control group with normal C.M.I. were further investigated in various condition of stimulation for cellular response in inflammation, chemotaxis, phagocytic activity and polysaccharide content in the granulocyte citoplasm. In general the former activity was not depressed, chemotaxis and phagocytic values were deficient, polysaccharide content appeared the same in the normal (control) and in the immune deficient group.

Age Factors↗