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Biomedical subjects

A Tirelli

Publications and source records attributed to A Tirelli.

At least 19 recordsLinked to original sources
PubMed2001

Effects of beta-endorphin and met-enkephalin on platelet activity.

In the present study, beta-endorphin and met-enkephalin were tested for their antiplatelet activity in human platelet-rich plasma (PRP). Blood samples were obtained from 15 healthy subjects. The results of the study show that these two endogenous opioids (200 pg/ml final concentration) reduce platelet aggregation when it is induced by ADP at low dose (0.5 microM). It is likely due to conformational changes on the platelet membrane that cause a non-specific decreased susceptibility to platelet-aggregating agonists.

Adenosine Diphosphate↗
PubMed2000

Biclonal gammopathy and platelet antibodies in a patient with chronic hepatitis C virus infection and mixed cryoglobulinemia.

The presence of biclonal gammopathy [immunoglobulin (Ig)Mk + IgAlambda] and platelet antibodies in a patient with chronic hepatitis C virus (HCV) infection is reported. A type-II cryoglobulinemia (IgMk and polyclonal IgG) has also been detected. The IgAlambda monoclonal component still persists after removal of the cryoprecipitate. Two populations of atypical lymphoid cells with plasmocytoid features in bone marrow have been detected. They express IgM with k restriction and IgA with lambda restriction, respectively. These cells are CD19+, CD5+, bc12+, and Ki67-. Liver biopsy shows lymphoid infiltrates with features of B follicles. Thrombocytopenia with platelet antibodies but without splenomegaly is also present. This case is interesting because two hematologic extrahepatic manifestations simultaneously occur in a patient with HCV infection. Moreover the association between HCV and biclonal gammopathies has never been reported.

Antibodies↗
PubMed2000

Computer-assisted EEG monitoring during carotid endarterectomy.

The purpose of this study was to develop a reliable method of EEG analysis during carotid endarterectomy. EEGs of 104 patients under general anesthesia were processed by three different methods: a) "on-line" visual analysis during surgery, b) "off-line" visual analysis in laboratory, and c) computer analysis. To identify pathological EEGs, variability and asymmetry indexes of the 0.5-3.5 Hz and 8-15 Hz bands, absolute power and variability indexes of spectral edge frequency (SEF), and main dominant frequency were evaluated. On-line visual analysis showed clamp-related modifications in 29 EEGs (27.9%). Off-line visual analysis detected 24 pathological EEGs (23.1%): 18 with major changes and 6 with moderate changes. Computer analysis showed 21 EEGs (20.19%) with at least one altered index and 7 (6.7%) with altered variability for both SEF and 8-15 Hz power. The statistical analysis was significant for SEF variability and for 8-15 Hz power variability and asymmetry (P < 0.0001, analysis of variance test). While SEF and 8-15 Hz power variability did not appear influenced by anesthesia and single electrode artifacts, 8-15 Hz power asymmetry index was confounded by the presence of contralateral internal carotid occlusion. The data show that the use of these spectral indexes adds objective information to visual analysis, supporting and making easier intraoperative strategies. Their routine clinical use does not involve additional costs remaining technical requirements unchanged compared to traditional recording.

Aged↗
PubMed1998

Improved method for the determination of furosine in food by capillary electrophoresis.

A previously described method for determination of furosine by capillary zone electrophoresis in food has been improved for greater accuracy and sensitivity. Acid-hydrolyzed samples are subjected to solid phase extraction; then they are dried and redissolved before injection. The electrophoresis separation is performed in a fused silica capillary tube (50 microns inside diameter) with an extended-path-length detection cell using a 3-(N-morpholino)-2-hydroxypropanesulfonic acid solution at pH 7.0 as run buffer. The in-laboratory repeatability was within +/- 7.1% at the 95% confidence level when the amount of furosine ranged between 8 and 250 mg per 100 g protein. The values of both repeatability and sensitivity fulfill the requirements stated in the EU and Italian regulations for furosine determination in pasteurized milk and Mozzarella cheese. The data obtained on 48 different food samples including heat-treated milk, cheeses, and durum wheat products were comparable with those obtained by an HPLC method and proved to be accurate for furosine values up to at least 400 mg per 100 g protein. The furosine values found in cultured fresh cheese samples suggest that the use of this furosine index holds promise for the characterization of this type of cheese.

Animals↗
PubMed1997

Effect of insulin on blood rheology in non-diabetic subjects and in patients with Type 2 diabetes mellitus.

We evaluated the effect of insulin on platelet function, blood viscosity, and filterability in healthy subjects and in patients with Type 2 (non-insulin-dependent) diabetes mellitus. Fifteen diabetic patients were free from cardiovascular complications (group A), while the other 15 patients had both clinical and measured evidence of coronary or peripheral vascular disease (group B); 15 non-diabetic subjects served as controls. On blood samples taken without stasis, maximal platelet aggregation to 1.25 micromol l(-1) ADP, blood and plasma viscosity, and blood filterability were measured in basal conditions, and after incubation of blood, plasma or platelet-rich plasma with insulin at two physiological concentrations (120 and 480 pmol l(-1)). Compared with healthy subjects, the diabetic patients of group B had higher values of blood (p < 0.01) and plasma (p < 0.05) viscosity, and platelet aggregation response to ADP (p < 0.01), as well as lower values of blood filterability (p < 0.01). The diabetic patients of group A had values intermediate between normal subjects and the patients of group B. In non-diabetic subjects, insulin significantly decreased platelet aggregation and blood viscosity at low shear rates (22.5 s(-1)) (p < 0.01 for both), and had no significant effects on other parameters. In the diabetic patients of group A, insulin decreased blood viscosity at high (225 s(-1)) rates of shear (p < 0.01) and increased blood filterability (p < 0.01). The effects of insulin were not dose-related. In the diabetic patients of group B, none of the parameters evaluated was significantly influenced by insulin. Type 2 diabetic patients present many abnormalities of the rheologic properties of blood. The beneficial effects of insulin on platelet aggregation and blood viscosity are not evident in Type 2 diabetic patients, especially those with vascular complications and this may be relevant to the development of those complications.

Adenosine Diphosphate↗
PubMed1997

[Blood flow assessment with Doppler color ultrasonography in primary and secondary tumors of the liver].

Our study was aimed at measuring hemodynamic changes in liver perfusion in patients with HCC and hepatic metastases using color Doppler US, a noninvasive investigation technique. Eighty-seven patients were examined: 14 of them had HCC and 34 had metastases; the control group consisted of 39 people. Blood flow was measured in the common hepatic artery and portal vein and the ratio of hepatic arterial to total liver blood flow (HPI = hepatic perfusion index) and the ratio of hepatic arterial to portal venous blood flow (A/V ratio) were calculated. HPI and A/V values were changed in HCC patients (HPI = 0.23, range: 0.16-0.35; A/V = 0.32, range: 0.19-0.55) as a consequence of reduced portal venous blood flow (9.76 +/- 2.51 cm3/s) and of increased hepatic arterial flow (2.78 +/- 0.46 cm3/s). HPI and A/V values were significantly changed also in the patients with hepatic metastases (HPI = 0.24, range: 0.11-0.38; A/V = 0.34, range: 0.12-0.61) compared with the control group. These changes were correlated with increased hepatic arterial blood flow (3.16 +/- 1.35 cm3/s) and decreased portal venous blood flow (10.39 +/- 3.81 cm3/s). These results prove the role of color Doppler US in the study of primary liver cancer and metastases. Additional examinations are nevertheless necessary to assess the diagnostic value of color Doppler US in the early detection of and discrimination between benign and malignant tumors.

Adolescent↗
PubMed1995

Hyperbaric oxygen, oxygen-ozone therapy, and rheologic parameters of blood in patients with peripheral occlusive arterial disease.

For many years, clinical practice has consolidated the use of both hyperbaric oxygen and oxygen-ozone therapy in the treatment of peripheral occlusive arterial disease (POAD). We investigated the influence of these treatments on hemorrheologic parameters that play an important role in the pathogenesis and the clinical course of arteriosclerosis. Two groups of 15 patients suffering from POAD, assigned at random either to a cycle of HBO therapy or O2-O3 therapy, were evaluated for blood viscosity, erythrocyte filterability, hematocrit value, fibrinogen concentration, and thrombin time. The O2-O3 therapy caused a significant increase of erythrocyte filterability and a significant decrease of blood viscosity. By contrast, HBO therapy did not produce any significant change. The increase of lipid peri-oxidation, proved by raised malonyldialdehyde plasma levels, seems a likely mechanism involved in the hemorrheologic effects of O2-O3 therapy.

Aged↗
PubMed1994

Hemorheological and cardiovascular responses to beta-endorphin and naloxone in healthy subjects and in patients with essential hypertension.

The purpose of the present study was to determine if opioid agonism (beta-endorphin) and antagonism (Naloxone) exert rheological and cardiovascular effects in normal humans and in patients with essential hypertension. Eight hypertensive patients were matched for age, sex, and body habitus (body mass index, waist to hip ratio) with eight normotensive healthy subjects. In all subjects, heart rate and blood pressure (continuous automatic recording), blood and plasma viscosity, fibrinogen, hematocrit, and platelet aggregation to ADP were evaluated during an infusion of human synthetic beta-endorphin (0.5 mg/h). On a different day and in randomized order, the subjects were submitted to another beta-endorphin infusion preceded by an i.v. naloxone bolus (5 mg in 5 min). beta-Endorphin and naloxone failed to significantly alter heart rate or blood pressure in both normotensive and hypertensive subjects. In hypertensive patients, beta-endorphin significantly increased blood viscosity and ADP-induced platelet aggregation, but only the former effect was naloxone-sensitive. In normotensive subjects, beta-endorphin caused a transient but significant decrease of platelet aggregation that was reversed by naloxone. These data suggest that beta-endorphin may play some role in the inhibitory control of platelet aggregation in normal subjects. An altered responsiveness of some rheological determinants to beta-endorphin seems to be present in human hypertension.

Adenosine Diphosphate↗
PubMed1992

Glutathione (GSH) improved haemostatic and haemorheological parameters in atherosclerotic subjects.

Blood samples from ten patients with clinically evident manifestations of atherosclerotic disease were used to evaluate in vitro the effects of exogenous glutathione (GSH) on platelet aggregation and on blood filtration and viscosity. In two groups, each of ten atherosclerotic patients, matched for sex, age, prevalent localization, duration and gravity of disease, the effects of GSH infusion (600 mg every day for seven days) on the haemocoagulative pattern, platelet aggregation and blood filtration and viscosity were evaluated in a double-blind, placebo cross-over trial. The GSH in vitro addition resulted in a significant increase in blood filtration and a significant decrease in blood viscosity and platelet aggregation. The venous GSH infusion both significantly decreased blood viscosity and increased blood filtration. Partial thromboplastin time was lengthened after GSH infusion even thought it remained in the normal range.

Aged↗
PubMed1985

[Accentuated and irregular post-maximal deflection in thromboelastographic tracings: occurrence in various pathologies].

The increased and irregular post-maximal deflection of the two limbs of thromboelastographic traces has been variably interpreted by the Authors who utilize TEG as a global screening test for haemostasis evaluation. These thromboelastographic patterns have been attributed either to enhanced fibrinolytic activity or to raised clot's rectractility or even to incorrect technique. In our study, 1701 TEG's traces carried out in the last five years have been reviewed in order to evaluate the incidence of such patterns in both healthy subjects and in patients affected by different diseases. The data obtained show that such irregular post-maximal deflection's patterns are quite absence in healthy subjects while reaches a statistically significant incidence only in patients affected by diabetes mellitus, obesity or systemic hypertension. The results seem to suggest that the increased and irregular post-maximal TEG deflection is not a simply product of technique's mistake but may represent an useful index of some haemostatic alterations which need further studies.

Adult↗
PubMed1984

[Effects of low O2 tension on platelet aggregation].

Several studies in animals suggest a link between haemocoagulative patterns and blood gas changes. Furthermore platelet functions seem to be affected by O2 concentrations. In the present study we have evaluated "in vitro" the effect of low PO2 concentrations on platelet aggregation in man. In 15 normal subjects (mean age 32 +/- 5) platelet aggregation ADP (end conc. 1,25 microM) and collagen induced 2 micrograms/Ml) was determined before and after exposition to low PO2 concentrations (O2 conc. 5,04%). The results show that low PO2 concentrations determine a significant increase (P less than 0,001) of platelet aggregation as compared to controls. Although the mechanism of the direct influence of PO2 concentrations upon human platelet is unclear, this finding suggest new therapeutic approaches in chronic lung obstructive diseases.

Adenosine Diphosphate↗
PubMed1984

P50 values determined by tonometry and by simplified techniques.

Actual determination of the position of the oxygen hemoglobin dissociation curve (P50) was compared to three methods of estimating P50 in 39 patients with various diseases. There was a significant correlation between determined and estimated P50 values (P less than 0,001) for each of the methods studied. The data suggest that calculating P50 is reliable and may replace the need for actual measurement.

Adult↗
PubMed1984

Depressed antithrombin III biological activity in opiate addicts.

Antithrombin III activity was significantly decreased in opiate addicts, but no difference was found between addict and control groups in antithrombin III plasma concentration. Moreover, glycosylated haemoglobin concentration was increased in opiate addicts, but no correlation between glycosylated haemoglobin and antithrombin III activity was found. These data show that in opiate addicts there is depressed biological activity of antithrombin III. Further characterisation of the molecular changes in antithrombin III in addicts is needed to establish whether the impaired activity is affected by altered glucose metabolism.

Adolescent↗
PubMed1984

Rapid decrease of platelet aggregation (ADP--and collagen--induced) and of platelet circulating aggregates by the artificial pancreas in insulin-dependent diabetics.

The aim of the present study was to evaluate the role of the strict metabolic control achieved with the aid of an artificial pancreas (Biostator, Miles) on platelet functions in insulin-dependent diabetics (n = 20). Platelet aggregation responses to both ADP and collagen, as well as circulating platelet aggregates according to Wu and Hoak, were determined before and after 24 hours of complete metabolic control; as control group, 18 insulin-dependent diabetics were only monitored without attempts to normalize their blood glucose behaviour. A significant decrease in ADP induced aggregation (p less than 0.01) and circulating platelet aggregates (p less than 0.001) was observed in diabetics during the period of strict metabolic control. No changes were observed in the control group. The present data suggest that the increased platelet activity in diabetes is a consequence of the metabolic derangement of the disease.

Adenosine Diphosphate↗
PubMed1983

[Changes in mean erythrocyte volume and 2,3-diphosphoglycerate in two groups of diabetic subjects].

Mean corpuscular volume and Red Blood Cell 2-3, diphosphoglycerate in insulin dependent diabetics and in non insulin dependent diabetics were evaluated. Only in insulin dependent diabetics an increased mean corpuscular volume was found while in non insulin dependent diabetics red blood cell 2-3, DPG level appears to be reduced. These findings were not correlated with the metabolic parameters neither they seemed to be dependent upon sex, age or vascular disease. The Authors suggest that the increase of mean corpuscular volume might be indicative of a tendency to macromegaloblastosis in insulin dependent diabetics; with regard to RBC 2-3, DPG level it seems to be extremely variable in dependence on oxygen request at the tissue level.

2,3-Diphosphoglycerate↗
PubMed1983

[Effect of pentoxifylline on the dissociation curve of oxyhemoglobin].

In 9 subjects with peripheral vascular insufficiencies the AA. have studied the behaviour of the oxyhaemoglobin dissociation curve before and after pentoxyphilline infusion. After this drug no variations were observed as it regards MCHC, 2-3-DPG and so on; however a positive correlation was found between 2-3-DPG and the Hill number. These results suggest that 2-3-DPG may influence the Hill number (which is the expression of the gradient of the oxyhaemoglobin dissociation curve) and therefore may interfere with O2 transport.

Aged↗