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Biomedical subjects

A Bassi

Publications and source records attributed to A Bassi.

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

Reduced susceptibility to oxidation of low-density lipoprotein in patients with overproduction of nitric oxide (Bartter's and Gitelman's syndrome).

BACKGROUND: The oxidation of low-density lipoprotein (LDL) might play an important role in the development of atherosclerosis. OBJECTIVE: To establish whether greater than normal production of nitric oxide (NO) in vivo protects LDL from oxidation. PATIENTS AND METHODS: We studied nine subjects affected by Bartter's and Gitelman's syndrome (both characterized by greater than normal production of NO), and 10 subjects matched for age, sex and lipid levels as controls. LDL particles were isolated from plasma by density gradient ultracentrifugation. Susceptibility of LDL to oxidation was evaluated after incubation with copper sulfate solution, by measuring the formation of conjugated dienes, the thiobarbituric acid-reactive substances, and the volatile peroxidation products of n-3 (propanal) and n-6 (pentanal and hexanal) polyunsaturated fatty acids. Phospholipid fatty acid composition of LDL was determined by gas chromatography. LDL alpha-tocopherol concentrations were measured. RESULTS: Patients with Bartter's and Gitelman's syndrome had LDL particles smaller and/or denser than those of controls [Rf = 0.38 +/- 0.03 versus 0.42 +/- 0.02 (mean +/- SD), P < 0.01], which hence were assumed to be more oxidizable. The phospholipid fatty acid composition of LDL and the alpha-tocopherol concentrations did not significantly differ between patients and controls. The duration of the lag phase, which is the time preceding formation of conjugated dienes, did not differ between groups, but the lag phase times were related to urinary excretion of nitrite/nitrate from patients (r = 0.66, P < 0.05). Moreover, patient LDL had produced less thiobarbituric acid-reactive substances after 5 h (P < 0.04), and less pentanal and hexanal after 5 and 6 h (P < 0.04 and P < 0.02, respectively) than had that of controls. CONCLUSIONS: Greater than normal production of NO in vivo is associated with lower than normal susceptibility of LDL to oxidation in vitro, suggesting that NO plays a protective role in the development of atherosclerosis.

Adult↗
PubMed1997

Interhemispheric differences of hand muscle representation in human motor cortex.

Focal magnetic transcranial stimulation (TCS) is employed for mapping of the motor cortical output to abductor digiti minimi (ADM) muscle. The aim of this study was to evaluate the interhemispheric asymmetries in normals. Motor maps were obtained through motor evoked potentials (MEPs) recordings from ADM muscle in 20 healthy subjects in right and left hemispheres TCS. Measurement of several indexes such as excitability threshold, MEPs amplitude, MEPs latency, and silent period duration did not show differences between the hemispheres. Moreover, no interhemispheric asymmetries were found when the amplitude ratio values were analyzed. The hand motor cortical area, as represented by the number of responsive sites (3.6 vs. 3.5) and the "hot spot" site localization presented a fairly symmetrical organization. Absolute values displayed a relatively wide intersubject variability, while their interhemispheric differences were extremely restricted. This observation can offer a new tool in diagnosing and following up neurological disorders affecting the central motor system, mainly for those concerning monohemispheric lesions.

Adult↗
PubMed1997

Effects of increasing doses of apomorphine during stereotaxic neurosurgery in Parkinson's disease: clinical score and internal globus pallidus activity. Short communication.

We analysed the firing activity of internal globus pallidus cells in two Parkinson's disease patients undergoing stereotaxic surgery. Both patients showed an advanced rigid-akinetic syndrome with disabling levodopa induced dyskinesias. Apomorphine, intraoperatively administered at doses (1-2 mg) inducing a short but clear clinical improvement without involuntary movements, reduced the pallidal discharge rate by > 50% in both patients. An higher apomorphine dose (2.5 mg), tested in one hemisphere, blocked the firing activity with a time course independent from the occurrence of dyskinesias. These finding suggest that the reduction of internal pallidus excitability is one of the mechanisms underlying the efficacy of dopaminergic therapy, but also that changes in other basal ganglia stations are likely to be involved in dyskinesias.

Antiparkinson Agents↗
PubMed1997

Pharmacological evidence that the activation of the Na(+)-Ca2+ exchanger protects C6 glioma cells during chemical hypoxia.

1. In C6 glioma cells exposed to chemical hypoxia a massive release of lactate dehydrogenase (LDH) occurred at 3 and 6 h, coupled with an increased number of propidium-iodide positive dead cells. 2. Extracellular Na+ removal, which activates the Na(+)-Ca2+ exchanger as a Na+ efflux pathway and prevents Na+ entrance, significantly reduced LDH release and the number of propidium iodide positive C6 cells. 3. During chemical hypoxia, in the presence of extracellular Na+ ions, a progressive increase of [Ca2+]i occurred; in the absence of extracellular Na+ ions [Ca2+]i was enhanced to a greater extent. 4. The blockade of the Na(+)-Ca2+ exchanger by the amiloride derivative 5-(N-4-chlorobenzyl)-2',4'-dimethylbenzamil (CB-DMB), lanthanum (La3+) and the Ca2+ chelator EGTA, completely reverted the protective effect exerted by the removal of Na+ ions on C6 glioma cells exposed to chemical hypoxia. 5. The inhibition of the Na(+)-Ca2+ antiporter enhanced chemical hypoxia-induced LDH release when C6 glioma cells were incubated in the presence of physiological concentrations of extracellular Na+ ions (145 mM), suggesting that the blockade of the Na(+)-Ca2+ antiporter during chemical hypoxia can lead to increased cell damage. 6. Collectively, these results suggest that activation of the Na(+)-Ca2+ exchanger protects C6 glioma cells exposed to chemical hypoxia, whereas its pharmacological blockade can exacerbate cellular injury.

Amiloride↗
PubMed1997

Migraine with and without aura in the same patient: expression of a single clinical entity?

Migraine with aura and migraine without aura may be different clinical expressions of one disease. This theory is debated, however. In order to further address the issue, we administered a standardized questionnaire to 45 migraineurs. The results indicate a significant overlap between migraine with and without aura, most importantly with respect to response to therapy; 70% of patients had similar responses.

Adult↗
PubMed1997

Autotransfusion in major orthopaedic surgery: experience with 1785 patients.

Using a prospective audit, we have evaluated the efficacy of an integrated autotransfusion regimen which comprised predepositing and intra- and postoperative blood salvage in major orthopaedic surgery. We examined prospectively the records of 1785 patients (1198 females, 5867 males, mean age 62 (range 16-90) yr, preoperative haemoglobin concentration 13.4 (SD 1.4) g dl-1) undergoing total hip arthroplasty (THA, 1229 patients), THA after removal of internal fixation devices (RFD + THA, 18 patients), total knee arthroplasty (TKA, 263 patients), revision surgery of the hip (HR cup + stem revision, 197 patients; cup revision, 53 patients; stem revision, 16 patients) and total knee revision (TKR, nine patients). We estimated that the number of predonations (MSBOS = maximum surgery blood order schedule) was 2 u. for THA, TKA and TKR, and 3 u. for partial or total hip revision and total hip arthroplasty with fixation removal. We found that it was possible to obtain the MSBOS in 1597 patients (89.5%). Homologous red blood cell (HRBC) transfusions were carried out in 131 patients (7.3%). We found that the need to use HRBC was significantly associated with failure to meet the number of MSBOS, female sex, lower preoperative haemoglobin concentration, use of calcium heparin for antithrombosis prophylaxis, more extensive surgery, higher ASA rating and co-existing diseases such as coronary artery disease.

Adolescent↗
PubMed1997

Mapping of motor cortical reorganization after stroke. A brain stimulation study with focal magnetic pulses.

BACKGROUND AND PURPOSE: Focal transcranial magnetic stimulation (TCS) is used for noninvasive and painless mapping of the somatotopical organization of the motor cortex. TCS mapping of motor cortical output to the abductor digiti minimi (ADM) muscle was followed up in monohemispheric stroke patients by evaluating motor evoked potentials (MEPs). This approach allowed noninvasive investigation of the functional reorganization of hand motor areas. METHODS: Motor maps were constructed for 15 subacute stroke patients about 2 months from the ictus by recording MEPs from the ADM muscle via focal TCS in the affected hemisphere (AH) and unaffected hemisphere (UH) at the beginning of (T1) and after 8 to 10 weeks of neurorehabilitation (T2). Barthel Index and Canadian Neurological Scale scores were evaluated as well. An age-sex matched group of 15 healthy control subjects was enrolled to establish normative data. RESULTS: MEP excitability threshold was significantly higher in the AH of stroke patients than in normal subjects and in the UH (P < .001); excitability threshold was not significantly different between normal subjects and UH. In the AH, MEPs were significantly (P < .001) delayed in latency both in T1 and T2, with a significant decrease of the extenuation of motor output area to the ADM muscle (P < .05) in T1 versus control group and UH. This area was significantly enlarged (P < .05) in T2. Amplitude of MEPs from the AH, both at rest and during voluntary contraction, was significantly lower than normal in T1 (P < .001); it increased in T2 (P < .01) during relaxation but was still smaller than normal during contraction (P < .001). In combination with these findings, an improvement of Barthel Index and Canadian Neurological Scale scores (P < .001) was observed between T1 and T2 (P < .001). Central conduction time was prolonged in stroke patients both in T1 and T2. Changes in the shape of motor maps in the AH during follow-up in T2 were either isolated (therefore increasing the interhemispheric asymmetry) or also were "mirrored" on the UH. CONCLUSIONS: Our neurophysiological data are consistent with the presence of a rearrangement of the motor cortical output area and correlate well with an improvement of motor performances. These findings confirm the existence in adults of a "plasticity" in the central nervous system that is still operating between 2 and 4 months from the acute ictal episode. The observed neurophysiological modifications are significantly correlated with clinical improvement of disability and clinical scores.

Adult↗
PubMed1996

Toxicity evaluation of waters from a tributary of the River Po using the 7-Day Ceriodaphnia dubia test.

Seven-day toxicity tests with Ceriodaphnia dubia were used to assess ambient water toxicity in the River Lambro, a tributary of the River Po, and in the corresponding stretch of the main river located downstream from their confluence. About once a month, toxicity tests were conducted on water samples of the River Lambro, using as dilution water the water of the main river collected upstream from the confluence. With a lower frequency, the downstream stretch of the River Po was tested for ambient toxicity at four sites located at 6, 11, 16, and 21 km from the emission of the tributary. The River Lambro demonstrated variable toxicity in different time periods, although the most frequent effects were sublethal, on both reproduction and growth. Ammonia, nickel, and zinc can be indicated as possible toxicants. Acute toxic effects to C. dubia were observed with spring samples only, when the action of some pesticides, likely insecticides, have to be taken into account. Tests conducted on downstream water gave limited results, seemingly because the dilution capacity of the River Po reduced Lambro toxicity to a level close to and often below the detection limit of the 7-day test. Accordingly, toxic effects at downstream sites could only be observed on the growth of C. dubia, which was found to be the most sensitive endpoint. Fairly good agreement was found between predictions based on toxicity tests of the River Lambro and the effects observed for downstream samples.

Ammonia↗
PubMed1996

Selenium, zinc, and thyroid hormones in healthy subjects: low T3/T4 ratio in the elderly is related to impaired selenium status.

Iodothyronine 5' deiodinase, which is mainly responsible for peripheral T3 production, has recently been demonstrated to be a selenium (Se)-containing enzyme. The structure of nuclear thyroid hormone receptors contains Zinc (Zn) ions, crucial for the functional properties of the protein. In the elderly, reduced peripheral conversion of T4 to T3 with a lower T3/T4 ratio and overt hypothyroidism are frequently observed. We measured serum Se and RBC GSH-Px (as indices of Se status), circulating and RBC Zinc (as indices of Zn status), thyroid hormones and TSH in 109 healthy euthyroid subjects (52 women, 57 men), carefully selected to avoid abnormally low thyroid hormone levels induced by acute or chronic diseases or calorie restriction. The subjects were subdivided into three age groups. To avoid under- or malnutrition conditions, dietary records were obtained for a sample of 24 subjects, randomly selected and representative of the whole population for age and sex. Low T3/T4 ratios and reduced Se and RBC GSH-Px activity were observed only in the older group. A highly significant linear correlation between the T3/T4 ratio and indices of Se status was observed in the older group of subjects (r = 0.54; p < 0.002, for Se; r = 0.50; p < 0.002, for RBC GSH-Px). Indices of Zn status did not correlate with thyroid hormones, but RBC Zn was decreased in older as compared with younger subjects. We concluded that reduced peripheral T4 conversion is related to impaired Se status in the elderly.

Adult↗
PubMed1996

Influences of lipid and non-lipid nutritional parameters on factor VII coagulant activity in normal subjects: the Nove study.

Community-based studies have suggested that the dietary intake of total fat influences factor VII coagulant activity (FVIIc), a predictor of fatal events from coronary heart disease (CHD). Nevertheless, the question whether the quality of dietary fats, with special reference to fatty acids (FAs), influences FVIIc is unsolved. The authors investigated in 90 healthy volunteers living in Nove, a village near Vicenza (northern Italy), the relationships between FVIIc and the plasma concentration of individual FAs. Several indices of other nutritional factors that have recently received increasing attention as determinants of CHD risk (antioxidant vitamins A and E, oligoelements) were also included in the multivariate analysis. The stepwise multiple linear regression analysis revealed body mass index (BMI), and the concentrations of plasma stearic acid (C18:0) and serum copper as significant independent predictors of a substantial proportion of FVIIc variability (R = 0 center dot 52; R2 = 0 center dot 27; P < 0 center dot 001). This study substantially supports the role of the plasma concentration of stearic acid as an important factor in modulating FVIIc.

Adult↗
PubMed1996

Use of high sumatriptan dosages during episodic cluster headache: three clinical cases.

The authors describe three patients with episodic cluster headache whose attacks were all treated with subcutaneous sumatriptan. The patients described had a high frequency of attacks (more than two per day); therefore, far higher dosage of the drug was taken than commonly used in cluster headache. The patients did not experience any particular side effects, neither during the treatment period nor on abrupt withdrawal of the drug. Moreover, neither tachyphylaxis nor addiction were observed. The authors point out both the efficacy of sumatriptan, confirmed in all the treated attacks, and its safety even at higher dosages than recommended.

Adult↗
PubMed1996

Cryoglobulinemia in hepatitis C virus chronic active hepatitis: effects of interferon-alpha therapy.

We investigated the prevalence of mixed cryoglobulinemia (MC) in 100 cases of chronic hepatitis C virus (HCV) infection and the effect of a 6-month treatment with interferon-alpha (IFN-alpha). Cryoglobulins were detected on admission in 36 of 100 patients and appeared during observation in a further 18 cases. Cryocrit ranged from 0.5% to 20%. Patients with MC were older and had a higher incidence of cirrhosis than those without MC. Immunologic characterization of the cryoprecipitate showed the presence of type II in 84% of cases and type III in 16%. The patients received IFN-alpha (6 MU three times per week) for 6 months. Fifty-seven were responders (i.e., reached normal aminotransferase levels), 26 of these relapsed within 2 months after IFN withdrawal, and 30 did not relapse. After IFN-alpha treatment, cryoglobulinemia disappeared in 11 of the 21 evaluable responders, but in none of the 15 nonresponder patients (p < 0.003). The clearance of MC was associated in all cases with clearance of HCV RNA. The delayed appearance of cryoglobulinemia in responders seems to be associated with a higher probability of relapse.

Adjuvants, Immunologic↗
PubMed1996

Short-term diabetic ketosis alters n-6 polyunsaturated fatty acid content in plasma phospholipids.

At present, no information is available about the possibility that acute loss of metabolic control might be able to modify fatty acid composition in IDDM patients. Therefore, the aim of this study was to determine whether a short-term period of ketosis has any effect on the composition of fatty acid of plasma phospholipids in a group of insulin-dependent diabetes mellitus (IDDM) patients. Eleven IDDM patients and nine healthy volunteers were studied. Patients were studied over a 2-day period; each 2-day period consisted of initial baseline measurements followed by a day of hyperglycemia and mild ketosis, which was promptly alleviated by insulin infusion. No significant difference in baseline percent fatty acid composition was observed between normal controls and IDDM patients. In IDDM patients, ketosis induced a significant decrease in percent arachidonic acid (20:4 n-6) content, with a significant parallel decline in n-6 total polyunsaturated fatty acids. A significant inverse correlation between the prevailing plasma glucose and the relative content of arachidonic acid in plasma phospholipids was observed (r = -0.35; P = 0.0488). A highly significant inverse correlation was observed between the change from baseline condition to ketosis of the ratio C20:4/C20:3, the product/precursor ratio for the reaction catalyzed by delta5-desaturase, and the values of hemoglobin A1c,(r = -0.855; P = 0.0015). In conclusion, short term diabetic ketosis is associated with a significant decrease in n-6 polyunsaturated fatty acid content in plasma phospholipids, especially arachidonic acid. This decrease in arachidonic acid appears to be related to the degree of metabolic derangement, whereas the influence of short-term diabetic ketosis on the ratio of C20:4 to C20:3 seems to be due to the degree of long-term metabolic control.

Adult↗
PubMed1996

Anomalous phospholipid n-6 polyunsaturated fatty acid composition in idiopathic calcium nephrolithiasis.

Anomalies in the erythrocyte transport of anions and cations have been described in idiopathic calcium oxalate nephrolithiasis and seem to play a pathogenetic role in this disease. In consideration of the hypothesis that the complex array of ion flux cell abnormalities is an epiphenomenon of an anomaly in the composition of cell membranes, this study investigated cell-membrane lipid composition. In idiopathic calcium oxalate renal stone formers, in which ion transport abnormalities were present, and in healthy control subjects, plasma and erythrocyte membrane lipid composition, the erythrocyte oxalate exchange, and Na/K/2Cl cotransport activity were evaluated. Furthermore, in stone formers, the effect of a 30-day fish-oil diet supplementation on plasma lipids, erythrocyte oxalate exchange, oxaluria, and calciuria was investigated. The effect of archidonic acid released by phospholipase A2 on anion-carrier phosphorylation and activity in erythrocytes was evaluated as well. Patients had a lower content of linoleic and higher concentration of archidonic acids in both plasma and erythrocyte membrane phospholipids, and an increased archidonic/linoleic acid ratio. The archidonic acid level correlated with the erythrocyte oxalate exchange and sodium cotransport activity. Fish-oil supplementation lowered calcium and oxalate urine excretion, and normalized the erythrocyte oxalate exchange. Phospholipase A2 increased the erythrocyte anion-carrier protein phosphorylation and the oxalate exchange. This study shows that idiopathic calcium nephrolithiasis in the patient group reported here is characterized by a systemic defect in phospholipid archidonic acid levels that might provide an answer to the link between genetic background, dietary habits, and renal lithiasis.

Adult↗
PubMed1996

[Assessment of complications of major orthopedic surgery: comparison of indobufen, calcium heparin, and low molecular heparin].

OBJECTIVE: Evaluation of incidence of postoperative thrombotic and haemorrhagic complications in autotrasfused patients undergoing blood predepositing, hemodilution, intra and postoperative blood saving and treated with indobufen, heparin calcine and low molecular weight heparin (enoxeparin). EXPERIMENTAL DESIGN: Comparative study. Length of follow up: 6 months. SETTING: Three division of Orthopaedic Surgery related to 1st Anaesthesiology and Intensive Care Unit of Rizzoli Orthopaedic Institute. PATIENTS: 980 consecutive patients admitted to hospital from 1-1-1992 to 30-6-1994 (321 males and 159 females), aged between 20 and 90 years (mean 62 +/- 11 years), with basal hemoglobin at 13.4 +/- 1.4 g/dI (range 6.7-17.9), who had undergone antithromboembolic prophylaxis with indobufen (Indo, 668), heparin calcine (CaHe, 200) and low molecular weight heparin (LMWH). INTERVENTIONS: Total hip (714) and knee (121) arthroprosthesis and hip replacements (cup 33, stem 10, cup and stem 102). MEASUREMENTS: The incidence of death, thromboembolic complications (pulmonary embolism, deep vein thrombosis), hemorrhage (hematoma and homologous transfusions), cardiac ischaemia. ANOVA and contingency tables (CT) were used for statistical. RESULTS: The absence of complications was significantly greater in patients treated with indobufen (Indo 94.3% vs CaHe 83.5% vs LMWH 85.7%, CT: p = 0.0001); the incidence of thromboembolic complications was significantly higher in patients treated with heparin calcine and low molecular weight heparin; in patients treated with heparin calcine the incidence of haemorrhagic complications was significantly higher. Due to bleeding brought about by the use of heparin calcine, one patient with coronary heart disease suffered from anemia and severe hypotensions by myocardiac infarction and cardiogenous shock which led to the patient's death. The use of homologous transfusions was significantly higher in patients treated with heparin calcine (Indo 4.2% vs CaHe 14.5% vs LMWH 4.5%, CT: p = 0.0001). CONCLUSIONS: In patients undergoing autotransfusion and hemodilution, indobufen has a lower of haemorrhagic complications compared to heparine calcine and low molecular weight heparin and it is more effective in the prevention of thrombotic complications at clinical evidence.

Adult↗