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Biomedical subjects

V Calabrese

Publications and source records attributed to V Calabrese.

At least 55 records · Page 3Linked to original sources
PubMed1996

Residual and recurrent acoustic neuroma in hearing preservation procedures: neuroradiologic and surgical findings.

Magnetic resonance imaging with gadolinium DTPA is currently the most accurate method for detecting small intracanalicular yestibular schwannomas. This imaging modality is not nearly as clear in diagnosis of a small residual or recurrent neuroma after a hearing preservation procedure. This study looked for gadolinium-enhanced MRI images mimicking recurrent lesions in 104 consecutive cases of unilateral acoustic neuroma removed with a hearing preservation technique by the retrosigmoid transmeatal approach. A number of cases with enhancing MRI images in the internal anditory canal were reoperated, permitting the histologic examination of the enhancing tissue. Criteria for the MRI diagnosis of residual-recurrent acoustic neuroma are presented, along with the short-to mid-term rate of "residual-recurrent" tumor.

Journal Article↗
PubMed1996

Neuropsychological assessment in a case of pseudoneurologic symptamology.

A 35-year-old woman undergoing an evaluation for possible multiple sclerosis had deficits in motor coordination, information processing speed, memory, verbal fluency and executive functions on neuropsychological testing Although presenting symptoms and cognitive impairments suggested multiple sclerosis, clinical history, personality features and neurologic workup were more consistent with a somatoform disorder This case illustrates the importance of interpreting neuropsychological deficits within a broad clinical context.

Journal Article↗
PubMed1996

Effects of Metadoxine on cellular status of glutathione and of enzymatic defence system following acute ethanol intoxication in rats.

The aim of the study was to determine whether a combination of pyridoxine and pyrrolidone carboxylate (PCA) could influence the antioxidant defence system in hepatic and extrahepatic tissues during acute ethanol administration. The results showed that ethanol treatment led to a significant depletion of reduced glutathione and increase in oxidized glutathione (GSSG) in the different organs, associated with decreased activity of glutathione reductase. Pretreatment of animals with Metadoxine (PCA + pyridoxine) one hour before ethanol administration produced a significant protection against glutathione (GSH) depletion in the different organs examined. This was consistent with an increase in glutathione reductase activity. In view of the fact that free thiol compounds such as glutathione are vital in cellular defence against oxidants and that decreases in reduced glutathione precede lethal cell injury resulting from free radical accumulation, our study supports the effectiveness of Metadoxine as a useful therapeutic agent effective in the management of all those pathological conditions where a severe imbalance of cellular redox state seems to take place as a result of the generation of free radical species.

Alcoholic Intoxication↗
PubMed1996

Changes in endogenous lipoperoxidation and antioxidant enzyme status induced by cysteine in the substantia Nigra.

It is generally accepted that reactive oxygen species have a major role in the mediation of cell damage and that free sulfhydryl groups are vital in cellular defence against endogenous or exogenous oxidants. Modification of cellular oxidant/antioxidant balance has been involved in the neuropathogenesis of several diseases, e.g., stroke, Parkinson's disease, Alzheimer's disease and physiological ageing. An increasingly important area of antioxidant defence is based on sulfhydryl chemistry, owing to the role of -SH groups in the function of macromolecular structures such as enzymes and cellular membranes. Thiols, however, may themselves generate deleterious free radicals. In the present study we provide experimental evidence suggesting a selective effect of cysteine in promoting reactions of oxidative stress in the brain areas of substantia nigra and septum, but not in other different areas which were associated with corresponding changes in the activity of antioxidant enzymes.

Animals↗
PubMed1995

Intratemporal hemangiomas involving the facial nerve: diagnosis and management.

Intratemporal vascular tumors involving the facial nerve are rare benign lesions. Because of their variable clinical features, they are often misdiagnosed preoperatively. This study presents a series of 21 patients with such lesions managed from 1977 to 1994. Facial nerve dysfunction was the most common complaint, present in 60% of the cases, followed by hearing loss, present in 40% of cases. High-resolution computed tomography, magnetic resonance imaging with gadolinium, and a high index of clinical suspicion is required for preoperative diagnosis of these lesions. Early surgical resection of these tumors permits acceptable return of facial nerve function in many patients.

Journal Article↗
PubMed1995

Effect of pyrrolidone carboxylate (PCA) and pyridoxine on liver metabolism during chronic ethanol intake in rats.

Rats subjected to chronic ethanol intake for a period of 28 days showed significant elevation in blood ethanol levels, a marked decrease in hepatic reduced glutathione (GSH) content and a decrease in liver tryptophan pyrrolase (TPO) activity. A daily intraperitoneal injection of a combined solution of pyrrolidone carboxylate (PCA) and vitamin B6 (pyridoxine hydrochloride) (0.3 mmoles/kg) into ethanol-treated rats resulted in the blood ethanol levels becoming significantly reduced, while the hepatic GSH content and TPO activity were markedly elevated. Our results support the view that PCA and pyridoxine operate to restore the redox imbalance of the hepatocytes caused by chronic alcohol intake.

Alcoholism↗
PubMed1995

Effects of metadoxine on cellular formation of fatty acid ethyl esters in ethanol treated rats.

Free fatty acids (FFA) and fatty acid ethyl esters (FAEE) were extracted from different organs of rats administered ethanol, which was found to have induced FAEE formation, which reached its highest levels in the heart, followed by kidney, brain and liver; the ethanol administration resulted also in a marked increase of total FFA content, particularly in brain, kidney, heart and liver. Pretreatment of animals with Metadoxine one hour before ethanol administration inhibited significantly both FAEE and FFA accumulation in all organs examined. These effects were concomitant with the decreased levels of ethanol in blood found in alcohol-intoxicated rats pretreated with Metadoxine. Our results point to the role of fatty acid ethyl esters as possible mediators in the production of alcohol-dependent syndromes, especially in organs lacking oxidative pathways. Administration of Metadoxine, through an increment in alcohol metabolism and turnover, greatly reduces this metabolic abnormality, warranting its potential usefulness as a pharmacological tool in alcoholism management.

Animals↗
PubMed1995

Compatibility of reduced glutathione (GSH) with different solutions currently used in anesthesia and reanimation.

BACKGROUND: Reduced glutathione (GSH) an antioxidant used for i.v. or i.m. administrations, prepared as powder to be diluted in distilled water just before injection (Tationil 600), could lose its antioxidant properties when added to various infusions currently utilized in anesthesia and reanimation. AIM OF THE WORK: Evaluate in vitro the compatibility of the compound marketed under the trade nome "Tationil 600" with the intravenous infusions in common use in anesthesia and reanimation. MATERIALS AND METHODS: 10 mg GSH (Tationil 600) were added to 10 ml of different solutions: 0.9% saline (I), 5% glucosate solution (II), Normosol-M and 5% glucose (III), 3.5% Emagel (IV), Propofol 10 mg/ml (V), in order to obtain a final solution containing 1 mg og GSH per ml of solution. The different solutions were incubated and aliquots taken at different times and analyzed. RESULTS: GSH in its commercial preparation proved to be compatible with all solutions examined with exception of solution III, because of the interference of sodium bisolfite. CONCLUSIONS: Reduced glutathione (Tationil 600) was compatible with solutions I, II, IV and V, used for i.v. administrations in anesthesia and reanimation, and revealed to maintain its antioxidant properties when studied over a period of 24 hours.

Anesthesia↗
PubMed1994

Changes in cerebrospinal fluid levels of malondialdehyde and glutathione reductase activity in multiple sclerosis.

The chemical composition of human cerebrospinal fluid (CSF) is considered to reflect brain metabolism. In this study we measured malondialdehyde (MDA) levels and the activity of enzymes involved in antioxidative processes, glutathione reductase and glutathione peroxidase, in human cerebrospinal fluid of multiple-sclerosis (MS) patients and normal healthy volunteers. Our results indicated that the cerebrospinal fluid in MS showed significantly higher endogenous levels of MDA than the control, as well as a much greater resistance to in-vitro stimulation test. In addition, we found the activity of GSH reductase significantly increased, about twice the control values, whereas the activity of glutathione peroxidase was markedly decreased as compared to control values. Our findings suggest that in MS the activity of antioxidant enzymes is modified, and indicates the conceivable possibility of a pathogenic role of oxidative stress in the determinism of the disease.

Antioxidants↗
PubMed1993

Effects of metadoxine on cellular free fatty acid levels in ethanol treated rats.

Free fatty acids (FFA) and fatty-acid ethyl esters (FAEE) were extracted from different organs of rat after ethanol administration. The results showed that ethanol treatment increased the concentration of saturated and mono-unsaturated FFA and FAEE while decreasing the poly-unsaturated fatty-acid content. Pretreatment of animals with Metadoxine one hour before ethanol administration inhibited the increased formation of saturated and mono-unsaturated FFA. While ethanol administration induced a marked increase in glutathione (GSH) S-transferase activity correlated with increased formation of FAEE in different rat tissues examined, pretreatment of such rats with Metadoxine reduced considerably the increased enzyme activity of their GSH S-transferase. Elevated concentrations of saturated and mono-unsaturated FFA conceivably reflect changes in the composition of lipid membranes. Hence, the cellular response to ethanol would be the formation of highly-packed rigid membrane structures. Pretreatment with Metadoxine causes an inhibition in the formation of elevated quantities of saturated and mono-unsaturated fatty acids. This condition could result in a lower degree of adaptability to ethanol intake and perhaps a decreased level of tolerance to ethanol.

Animals↗
PubMed1991

Subtotal parathyroidectomy for secondary hyperparathyroidism in chronic renal failure.

Twenty-seven patients on chronic haemodialysis and with secondary hyperparathyroidism underwent subtotal parathyroidectomy during the period 1985-1989. The operation was indicated by severe clinical symptoms and evidence of radiological abnormalities not responsive to conservative treatment (low phosphorus diet, phosphate binding substances, oral calcium and vitamin D). If despite intensive medical management, inadequate control of parathyroid hyperplasia continues surgical intervention becomes necessary. Ultra-sonography was performed pre-operatively in all 27 cases and detected 42 of 99 glands (42.5 per cent). Also scintigraphy was carried out in every patient but it gave a relatively low detection rate (24.5 per cent). Surgery was followed by improvement in 20 patients and progression of hyperparathyroidism in seven cases. Three of the seven patients failed to improve after subtotal parathyroidectomy, necessitating a re-intervention; the remaining four responded sufficiently to medical therapy. From our experience we conclude that subtotal parathyroidectomy for renal hyperparathyroidism is recommended.

Adult↗
PubMed1991

[Central and peripheral monitoring of the cellular redox state after reduced glutathione administration in the rat].

In this study we measured reduced glutathione as DTNB reactive material in different brain areas as well as in liver and kidney of rat, before and after exogenous administration of GSH. Treatment with GSH produced an increase in DTNB positive material as well as a decrease of lipoperoxidation, in central and peripheral organs of rat, suggesting the possibility of an exogenous modulation of redox balance in mammalian cells.

Animals↗
PubMed1989

Primary malignant melanoma of the oral cavity.

Primary mucosal melanomas of the upper aero-digestive tract are uncommon and represent only 1.7 to 3 per cent of all primary melanomas. The most frequent localizations are the nasal fossae, the paranasal sinuses and the oral cavity where melanomas most often arise from the palate and alveolar ridge, buccal mucosa, lips, tongue and floor of mouth. The authors describe a case of malignant melanoma of the uvula, review the literature and discuss the aetiology, pathology and diagnostic and therapeutic problems.

Combined Modality Therapy↗
PubMed1989

[Effects of modulation of the redox system on endogenous lipoperoxidation in the rat central nervous system].

In this study we have measured malonaldehyde (MDA) as an index of endogenous lipoperoxidation, the latter being a relevant aspect of oxidative stress that occurs in different neuronal systems. Our results clearly demonstrate that in physiological conditions specific neuronal systems exhibit a different rate of MDA formation among which substantia nigra neurons show a particular vulnerability to oxidative stress. Chronic ethanol treatment significantly enhances MDA production, particularly at the level of cholinergic structures (septum) as well as in the dopaminergic system (substantia nigra) and cortex. On the other hand, treatment with glutathione is able to decrease MDA formation, pointing out the possibility of an exogenous modulation of redox balance in brain cells.

Animals↗
PubMed1988

Antibody to human and simian retrovirus, HTLV-I, HTLV-II, HIV, STLV-III, and SRV-I not increased in patients with multiple sclerosis.

We have tested sera from patients with multiple sclerosis, matched controls, and those with other neurological diseases, as well as sera from patients with the acquired immunodeficiency syndrome and controls and patients with tropical spastic paraparesis (TSP) and controls for antibody to human T-lymphotropic virus type I (HTLV-I), HTLV-II, human immunodeficiency virus (HIV), simian T-lymphotropic virus type III, or simian retrovirus type I by immunofluorescent activity test, and for HTLV-I and HIV by the ELISA method. Sera from patients with multiple sclerosis and matched controls, and from patients with optic neuritis and Parkinson's or other neuromuscular diseases did not have antibody to any of the retroviruses tested. Specimens from TSP patients and some controls contained HTLV-I antibody. We conclude from our study that only TSP patients had serological evidence of infection with one of the retroviruses studied.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Serologic studies of MS patients, controls, and patients with other neurologic diseases: antibodies to HTLV-I, II, III.

We have studied the frequency of human retrovirus antibody (HTLV-I, II, III) in the serum and CSF of patients with MS, matched controls, and patients with optic neuritis, idiopathic and postencephalitic Parkinson's disease, neuropathies, polymyositis, ALS, and postpoliomyelitis. Except for the postpoliomyelitis samples, all samples were collected prior to 1980. Contrary to a previous published report, no significant levels of antibody to HTLV-I, II, or III were found in the MS patients or controls. No retrovirus antibody was detected in patients with the other neurologic diseases.

Antibodies, Viral↗
PubMed1988

Intratemporal vascular tumours.

Hemangiomas of the temporal bone are uncommon benign tumours, occurring most frequently at two sites: the internal auditory meatus (IAM) and the geniculate ganglion. In this paper the authors discuss the pathology, clinical onset and features, and the therapeutic management of two of these lesions. A review of the literature is also presented, paying attention to the controversy regarding the origin, pathogenesis and histologic classification of this rare lesion of the temporal bone.

Adult↗