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Biomedical subjects

V Pengo

Publications and source records attributed to V Pengo.

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

High blood ketone body concentration in type 2 non-insulin dependent diabetic patients.

To assess the metabolic disturbances, and, in particular, the occurrence of high blood ketone body concentration in post-absorptive Type 2 (non-insulin-dependent) diabetic patients as compared to a matched normal population, a study was carried out in a group of 78 Type 2 diabetic outpatients matched for age and sex and in 78 normal individuals. In all subjects we measured HbA1c, and fasting levels of glucose, FFA, lactate, pyruvate, glycerol, alanine, 3-hydroxybutyrate, acetoacetate, uric acid, total cholesterol, triglycerides, creatinine, growth hormone, cortisol, glucagon, free insulin, and C-peptide. Multistix strips were used for urine ketone determination. As expected HbA1c, and plasma glucose were higher in Type 2 diabetics. This was associated with multiple metabolic disturbances as shown by higher circulating concentrations of FFA, glycerol and gluconeogenic precursors. Similarly, blood levels of ketones (351 +/- 29 vs 159 +/- 15 umol/l; P < 0.0001) were increased, in spite of higher plasma free-insulin (77 +/- 7 vs. 49 +/- 14 pmol/l; p < 0.0001) and C-peptide concentration (0.63 +/- 0.03 vs. 0.46 +/- 0.07 nmol/l; P < 0.05) and no differences in plasma levels of cortisol, and growth hormone. Plasma glucagon levels were higher in Type 2 diabetics. Blood ketone body levels were directly correlated with both plasma glucose and FFA concentrations. These observations clearly show that Type 2 diabetes is a pathologic condition characterised by multiple metabolic disturbances which are fully apparent in the basal state. Furthermore, we emphasise that Type 2 diabetic patients, though not insulin deficient, may present a significant increase in their fasting levels of ketone bodies.

Aged↗
PubMed1996

Autoantibodies to phospholipid-binding plasma proteins in patients with thrombosis and phospholipid-reactive antibodies.

Anti-phospholipid (aPL) antibodies are defined as antibodies detected in systems employing phospholipids (PL). This general definition is misleading as it comprises a large group of autoimmune phospholipid-reactive antibodies that are directed against specific phospholipid-binding plasma proteins, such as beta 2-glycoprotein I (beta 2GPI) and prothrombin. Definition of phospholipid-reacting antibodies according to the plasma protein against which they are directed appears more appropriate and could be useful in understanding clinical events and pathogenic mechanisms. Using ELISA systems we have studied the presence of antibodies directed against specific phospholipid-binding proteins in a series of 22 patients with thrombosis and phospholipid-reactive antibodies of the IgG isotype. High levels of anti-beta 2 GPI IgG were detected in all 22 patients. Normal values were calculated on the basis of OD values at 405 nm (OD405) obtained for 22 age- and sex-matched healthy subjects (cut off value = 0.401). Levels of anti-beta 2 GPI antibodies were linearly correlated with those of cardiolipin-reactive (aCL) antibodies. Eleven out of 22 patients (50%) had values of anti-prothrombin antibodies exceeding the cut-off value of 0.250. No relationship was found between the levels of anti-beta 2GPI and anti-prothrombin antibodies. Tests for antibodies against two natural inhibitors of blood coagulation, protein C and protein S, revealed elevated levels of anti-protein C IgG and anti-protein S IgG in 4 and 12 patients, respectively. A highly significant correlation between anti-protein C IgG and anti-protein S IgG values as well as between antibody titers against the two studied natural coagulation inhibitors and anti-prothrombin IgG was found. When comparing patients positive for aCL and presence or absence of a previous thrombotic episode (aCL+/T+ vs aCL+/T-), the positivity of anti-beta 2GPI IgG was found to be statistically associated with thrombosis. Conversely, among patients with previous thromboembolism with or without aCL (aCL+/T+ vs aCL-/T+ vs aCL-/T+) the positivity of anti-beta 2GPI IgG was strictly associated with the positivity of aCL, thus identifying the aPL antibody syndrome. These data demonstrate that anti-beta 2GPI antibodies are a marker of "autoimmune" thrombosis. Anti-prothrombin antibodies are not a marker of thrombosis and are closely associated with antibodies to protein C and protein S.

Antibodies, Antiphospholipid↗
PubMed1995

Binding of autoimmune cardiolipin-reactive antibodies to heparin: a mechanism of thrombosis?

Autoimmune CL-rA need a plasma protein, beta 2GPI, to bind anionic PL. While beta 2GPI could be the true antigen, beta 2GPI binding to solid phase heparin did not determine its recognition by CL-rA when using patient plasmas. We tested plasmas from four patients with antiphospholipid syndrome in this study and no CL-rA binding to heparin sepharose was obtained. On the contrary, when CL-rA were first purified from the plasmas by means of a CL-octyl sepharose column, the purified material bound to the heparin sepharose column. Thus, after recognizing beta 2 GPI, CL-rA bind heparin. 'In vivo' CL-rA binding to heparin like-substances could inhibit the anti-thrombotic properties of endothelial cells.

Adult↗
PubMed1995

Anti beta 2-glycoprotein I antibodies in a patient with catastrophic antiphospholipid syndrome.

Autoimmune antiphospholipid antibodies are a hallmark of patients with antiphospholipid syndrome, and require a protein cofactor, beta 2-glycoprotein I, to bind anionic phospholipids. In these same patients, moreover, IgG directly binding beta 2-glycoprotein I are described. We found high plasma titres of both IgM and IgG anti beta 2-glycoprotein I antibodies in a patient with catastrophic antiphospholipid syndrome. After passing plasma through a Sephacryl S-300 column, an identical distribution pattern between anti beta 2- glycoprotein I and anticardiolipin antibodies was observed. Moreover, when IgG immunocomplexes were isolated from a high molecular fraction, IgM anti- beta 2-glycoprotein I and anticardiolipin antibodies were detected. Thus IgG, IgM ad IgG-IgM complexes of anti-beta 2-glycoprotein I antibodies are present at the same time in a patient with antiphospholipid syndrome.

Acute Disease↗
PubMed1995

Autoimmune antiphospholipid antibodies are directed against a cryptic epitope expressed when beta 2-glycoprotein I is bound to a suitable surface.

The antiphospholipid antibodies (aPL) present in autoimmune disorders are associated with thromboembolic episodes, and their binding to phospholipids (PL) is mediated by a plasma cofactor, beta 2-glycoprotein I (beta 2GPI). Both PL and beta 2GPI seem necessary for binding, thus indicating that the two components comprise the epitope against which aPL are directed. Using an anti-beta 2GPI antibody ELISA with the antigen adsorbed onto polyvinylchloride (PVC) plates, we detected high antibody titres in 12 out of 12 plasma from patients with the antiphospholipid syndrome. No or very low positivity was obtained when the same ELISA was carried out in polystyrene (PST) plates, while an increasing positivity was found when processed (i.e. more hydrophilic) or COOH-surface PST plates were used. When beta 2GPI dependent IgG-aPL were purified using agarose-immobilized cardiolipin, 4 out of 4 preparations were highly positive in anti-beta 2GPI antibody ELISA using PVC plates, while beta 2GPI was not fully recognized by aPL-IgG when adsorbed onto PST plates. These findings demonstrate that aPL are, in fact, anti-beta 2GPI antibodies directed against a cryptic epitope which is expressed when beta 2GPI is bound to anionic phospholipid, or another suitable surface.

Adolescent↗
PubMed1994

IPO-V2: a prospective, multicenter, randomized, comparative clinical investigation of the effects of sulodexide in preventing cardiovascular accidents in the first year after acute myocardial infarction.

OBJECTIVES: This study was conducted to assess the efficacy of sulodexide, a glycosaminoglycan compound with antithrombotic properties, in preventing death and thromboembolic events after acute myocardial infarction. BACKGROUND: Antithrombotic therapy has been found to play an important role in the prevention of cardiovascular events and death after acute myocardial infarction. Glycosaminoglycan-containing compounds, including sulodexide, show profibrinolytic and antithrombotic properties that render them suitable for use in patients after infarction. METHODS: A total of 3,986 patients who had recovered from acute myocardial infarction were randomized to receive either the standard therapy routinely administered at each study center, excluding antiplatelet and anticoagulant drugs (control group, 1,970 patients), or the standard therapy plus sulodexide (treated group, 2,016 patients). Between 7 and 10 days after the episode of acute myocardial infarction, sulodexide was administered as a single daily 600-lipoprotein-lipase-releasing unit (LRU) intramuscular injection for the 1st month, followed by oral capsules of 500 LRU twice daily. Patients were evaluated for > or = 12 months. RESULTS: At the end of the study, 140 deaths (7.1%) were recorded in the control group and 97 (4.8%) in the sulodexide group (32% risk reduction, p = 0.0022, chi-square test). A total of 90 patients (4.6%) in the control group had a further infarction, compared with 66 (3.3%) in the sulodexide group (28% risk reduction, p = 0.035). Furthermore, a reduction in left ventricular thrombus formation (evaluated by echocardiography) was observed in the sulodexide group (n = 12; 0.6%), compared with values in the control group (n = 25; 1.3%) (53% risk reduction, p = 0.027). Sulodexide was well tolerated and devoid of significant adverse events. All significant results were confirmed by "actual treatment" analyses. CONCLUSIONS: The study provides evidence that long-term therapy with sulodexide started early after an episode of acute myocardial infarction is associated with reductions in total mortality, rate of reinfarction and mural thrombus formation.

Aged↗
PubMed1993

Purification of anticardiolipin and lupus anticoagulant activities by using cardiolipin immobilized on agarose beads.

We describe a novel method for the purification of aPL, in which pure CL is immobilized on octyl-sepharose beads by hydrophobic interaction. No lipid contamination was present in eluates, and the system could be reutilized three times without loosing extracting capacity. Four patients with antiphospholipid syndrome were studied. A marked decrease in aCL and LA activities was found in all patient plasmas after the passage through a CL-octyl-sepharose column. Both activities were recovered in eluates which contained beta 2-GP-I and IgGs. beta 2-GP-I was also present in normal plasma eluates, which showed no aCL and slight LA activity. This method represents an improvement in the purification of aPL, and could be useful in explaining the mechanism of action of antibodies that are obtained using pure phospholipid as extracting matrix.

Adolescent↗
PubMed1993

Antiphospholipid antibodies are not present in the membrane of gel-filtered platelets of patients with IgG anticardiolipin antibodies, lupus anticoagulant and thrombosis.

To explore the possibility of an interaction between platelets and antiphospholipid antibodies and its relationship with thromboembolic events, platelets from six patients with IgG anticardiolipin antibodies, lupus anticoagulant and thrombosis were isolated by gel filtration. Five patients had primary antiphospholipid syndrome and one had a form secondary to systemic lupus erythematosus. Two patients had mild thrombocytopenia. The six platelet membrane eluates contained less than 1.09 GPL units of anticardiolipin antibodies and displayed no lupus anticoagulant activity. Similarly, lysates of disrupted platelets did not show anticardiolipin or lupus anticoagulant activity. These results suggest that antiphospholipid antibodies do not interact with circulating platelets, at least in patients on oral anticoagulant treatment with no evidence of acute thrombosis.

Adult↗
PubMed1993

Reversal of excessive effect of regular anticoagulation: low oral dose of phytonadione (vitamin K1) compared with warfarin discontinuation.

To determine the best way to reverse the excessive effect of regular anticoagulation in patients with INR > 5 and no bleeding complications, 23 patients with INR > 5 were randomly subdivided into two groups: group A (n = 12) discontinued warfarin for one day and group B (n = 11) received 2 mg of vitamin K1 orally in addition to the usual warfarin dose. INR was determined after 24 h (day 1), after which both groups continued with their usual dose of warfarin. After 48 h (day 2), warfarin dosage was changed according to the INR value. On day 9, INR values were determined again. Five out of twelve patients in group A had INR values > 5 on day 1. One patient in group A had an INR value < 5 both on days 1 and 2. All eleven patients in group B had INR values < 5 on day 1, and all but one on day 2. On day 9, INR values were acceptable (INR 2.0-4.5) in ten group A patients and eight group B patients. These findings suggest that a low oral dose of vitamin K1 is a convenient treatment for excessive anticoagulation in patients with no bleeding complications.

Adult↗
PubMed1992

PAIMS 2: alteplase combined with heparin versus heparin in the treatment of acute pulmonary embolism. Plasminogen activator Italian multicenter study 2.

BACKGROUND: The effect of alteplase versus heparin in pulmonary embolism has not been studied extensively with serial pulmonary angiograms. OBJECTIVES: The aim of this randomized, open trial was to evaluate the efficacy and safety of alteplase followed by heparin, versus heparin alone, in 36 patients with angiographically documented pulmonary embolism. METHODS: Twenty patients were allocated randomly to a 2-h infusion of alteplase (10 mg bolus, then 90 mg over 2 h) followed by heparin; the other 16 patients were given intravenous heparin at a continuous infusion rate of 1,750 IU/h. RESULTS: The vascular obstruction, assessed by the Miller index at pulmonary angiography, decreased significantly in alteplase-treated patients (p less than 0.01) from a baseline of 28.3 +/- 2.9 to a value of 24.8 +/- 5.2 2 h after the start of infusion; in the heparin group there was no change (from 25.3 +/- 5.3 to 25.2 +/- 5.4). Mean pulmonary artery pressure decreased significantly from a baseline of 30.2 +/- 7.8 mm Hg to 21.4 +/- 6.7 in the alteplase group and increased in the heparin group (from 22.3 +/- 10.5 to 24.8 +/- 11.2 mm Hg). For a subset of patients, lung scans were performed at baseline and on days 7 and 30. There were no differences between the two groups in the follow-up lung scans, but there were significant decreases from the baseline values. Bleeding occurred in 14 of 20 alteplase-treated patients and in 6 of 16 in the heparin group (p = NS). There were three major bleeding episodes in the alteplase group and two in the heparin group. Two patients died after fibrinolysis (one of acute renal failure after cardiac tamponade and one of cardiac arrest after cerebral hemorrhage) and one patient in the heparin group died of recurrent pulmonary embolism. CONCLUSIONS: Alteplase resulted in a greater and faster improvement of the angiographic and hemodynamic variables compared with heparin. However, the high frequency of bleeding observed with alteplase in this trial suggests that patients should be carefully selected before thrombolytic therapy is given.

Acute Disease↗
PubMed1990

Renal artery thrombosis and hypertension in a 13 year old girl with antiphospholipid syndrome.

The case of a 13 year old girl with renal artery thrombosis and hypertension is described. A cerebrovascular accident and a probable occlusion of the superior mesenteric artery also occurred. Very high levels of 'lupus anticoagulant', anticardiolipin antibodies as well as false positive Venereal Disease Research Laboratory tests were repeatedly shown. Moreover, the patient fulfilled at least four classification criteria for systemic lupus erythematosus, but only a slight positivity for antinucleolar antibodies was present. The striking relation between antiphospholipid antibody levels and clinical events and the treatment of this complex syndrome are discussed.

Adolescent↗
PubMed1990

A brief contact of native whole blood with adenosine diphosphate (ADP) promotes the release of the contents of platelet alpha granules but not dense bodies and increases platelet retention to glass bead columns.

We have previously demonstrated that a brief contact of native whole blood with ADP, promotes a dose dependent release of the contents of platelet alpha granules. In the present study we have shown that in our system there is not a parallel release of the contents of platelet dense bodies as measured by the release of serotonin (5 HT). This early and partial platelet activation determines an increase in platelet retention in glass bead columns. After exactly 15 seconds of activation of native whole blood from 6 healthy volunteers with ADP, in fact, there was a significant fall in the platelet count following the flow of native whole blood across glass beads. A significant decrease (from x = 182,000 +/- 13,700 to x = 120,000 +/- 8,00/microliters p less than 0.001) was present when the blood was stimulated with 0.4 microM ADP final concentration. These results suggest that early, partial platelet activation by ADP could facilitate their possible adhesion to a suitable surface exposed along the vascular tree.

Adenosine Diphosphate↗
PubMed1989

The optimal therapeutic range for oral anticoagulant treatment as suggested by fibrinopeptide A (FpA) levels in patients with heart valve prostheses.

Fibrinopeptide A is a good marker of in vivo thrombin formation. The aim of oral anticoagulants (OA) is to lower in vivo thrombin formation. We therefore assessed FpA levels on several occasions in 38 patients receiving OA for artificial heart valve prostheses and in 20 patients receiving OA for biological heart valve prostheses. The mean FpA level, 1.82 ng ml-1 (SEM 0.14, n = 176), in patients with artificial valves was significantly higher than the mean, 1.02 ng ml-1 (SEM 0.4), obtained in 41 healthy subjects (P = 0.01). FpA mean value for biological valves was 1.41 ng ml-1 (SEM 0.14, n = 76), which was not significantly higher than controls (P = 0.08). A decrease in FpA levels, for both artificial and biological heart valve prostheses, was associated with a parallel increase in the intensity of anticoagulation. When considering FpA values obtained in the optimal therapeutic range for oral anticoagulant treatment, (International Normalized Ratio [INR] between 3 and 4.5), the mean level for artificial valves, 1.87 ng ml-1 (SEM 0.18, n = 102), was significantly higher than the mean value, 1.25 ng ml-1 (SEM 0.16, n = 55), obtained for biological valves. From a biological point of view, this indicates that artificial valves should be kept at a higher intensity of anticoagulation.

Administration, Oral↗
PubMed1989

[Advantages of a cardiologic ambulatory care facility specifically organized for patients undergoing treatment with oral anticoagulant drugs].

In patients with artificial heart valve prosthesis oral anticoagulants reduce but not eliminate the thromboembolic complications however, they do increase the risk of bleeding. In the present study, the incidence of thromboembolic and hemorrhagic complications in two homogeneous groups of patients with artificial heart valves on long term oral anticoagulant treatment has been evaluated. Group A (99 patients; total follow-up = 309 years) were resident in the Triveneto regions and received a questionnaire while group B (104 patients; total follow-up = 370 years) were referred to our department's centre for the control of oral anticoagulant treatment. Both groups were kept at a therapeutic range of 20-30% in terms of prothrombin activity. The incidence of thromboembolic and hemorrhagic complications is expressed as the number of episodes per 100 patient/years. Thromboembolic episodes were 2.6 (1.3 fatal) in group A while they were 1.08 (0.27 fatal) in group B; the reduction of fatal thromboembolic events was statistically significant (p less than 0.05). Hemorrhagic episodes were 1.9 (0.63 fatal) in group A while they were 0.81 (0 fatal) in group B. We concluded that an organized control of oral anticoagulant treatment in patients with artificial heart valves is advantageous as it significantly reduces fatal thromboembolism. Moreover, it could reduce the incidence of total thromboembolic and hemorrhagic episodes by more than 50%.

Administration, Oral↗
PubMed1987

Immunological specificity and mechanism of action of IgG lupus anticoagulants.

Although observations have implied that lupus anticoagulants have immunologic specificity toward anionic phospholipids, this assumption has been directly demonstrated in only one patient with a monoclonal IgM paraprotein. We tested the generality of this hypothesis directly by isolating five IgG lupus anticoagulants from patients with lupuslike syndromes and/or thrombosis. IgG lupus anticoagulant fractions were isolated free of other plasma proteins and free of contaminating phospholipid by adsorption to and elution from cardiolipin-cholesterol-dicetyl phosphate liposomes, followed by chromatography on protein A-Sepharose. Cardiolipin liposomes, but not phosphatidylcholine liposomes, were capable of removing all, or nearly all, lupus anticoagulant activity from patient plasma. The affinity-purified IgG preparations reacted with cardiolipin, phosphatidylserine, phosphatidylinositol, and phosphatidic acid, but not with phosphatidylcholine or phosphatidylethanolamine, and inhibited calcium-dependent binding of prothrombin and of factor X to phosphatidylserine-coated and to cardiolipin-coated surfaces. F(ab')2 fragments retained lupus anticoagulant activity and bound to cardiolipin in an enzyme-linked immunosorbent assay (ELISA). Anticardiolipin and lupus anticoagulant activity were both present in acidic fractions on isoelectric focusing. These data strongly suggest that most, if not all, lupus anticoagulants are antibodies that have immunologic specificity towards anionic phospholipids, thereby blocking the calcium-mediated binding of vitamin K-dependent coagulation factors to coagulation-active phospholipid surfaces.

Antibodies↗
PubMed1986

Adenosine diphosphate (ADP)-induced alpha-granules release from platelets of native whole blood is reduced by ticlopidine but not by aspirin or dipyridamole.

A brief contact between native whole blood and ADP promotes a dose-dependent release of platelet alpha-granules without a fall in the platelet number. We assessed the "ex vivo" effect of three widely used antiplatelet drugs, aspirin dipyridamole and ticlopidine, on this system. Aspirin (a single 800 mg dose) and dipyridamole (300 mg/die for four days) had no effect, while ticlopidine (500 mg/die for four days) significantly reduced the alpha-granules release for an ADP stimulation of 0.4 (p less than 0.02), 1.2 (p less than 0.01) and 2 microM (p less than 0.01). No drug, however, completely inhibits this early stage of platelet activation. The platelet release of alpha-granules may be related to platelet shape change of the light transmission aggregometer and may be important "in vivo" by enhancing platelet adhesiveness and by liberating the platelet-derived growth factor.

Adenosine Diphosphate↗