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Biomedical subjects

A Girolami

Publications and source records attributed to A Girolami.

At least 433 records · Page 24Linked to original sources
PubMed1984

Clearance and in vivo release by heparin of human platelet factor 4 (PF4) in the rabbit.

13 male New Zealand rabbits were injected with two different doses (25 micrograms/Kg and 100 micrograms/Kg) of human platelet factor 4 antigen (PF4). The disappearance of the protein was extremely fast with an half-life for the fast component of 1.07 +/- 0.16 and 1.76 +/- 0.11 min respectively. The half-life for the slow component, detectable only with the highest dosage, was 18.8 min. The administration of 2500 I.U. of heparin 30 min after PF4 administration induced a partial release of the injected protein and its clearance from plasma was slow, with half-life of 23.3 +/- 5.9 min and 30.9 +/- 2.19 min respectively.

Animals↗
PubMed1984

Prothrombin evaluation as obtained by kinetics studies of antigen-antibody reaction in a laser nephelometer.

Laser nephelometry is a technique which allows the evaluation of the concentration of several serum proteins and clotting factors. By means of this technique it is also possible to study the kinetics of the reaction between antigen and antibody. We studied the kinetics of the reaction between prothrombin and an antiprothrombin antiserum using several prothrombins namely: Prothrombin Padua, prothrombin Molise, which are two congenital dysprothrombinemias, cirrhotic, coumarin or normal prothrombins. Different behaviors in the kinetics of the reactions were shown even when the concentration of prothrombins was about the same in all plasma tested. These differences were analyzed by means of a computer (Apple II 48 RAM) programmed to solve four unknown equations (Rodbard's equation). From the data so obtained one can see that when voltages at the beginning and at the end of the reaction are in all cases about the same, a clear difference in the time required to reach half the maximum value of the voltage can still be demonstrated. This parameter, which is expressed in minutes, is longer in coumarin and prothrombin Molise than in controls. On the contrary it is shorter in prothrombin Padua and has about the same value of controls in the cirrhotic patient. Moreover the time at which the maximum rate is obtained is longer in coumarin and prothrombin Molise than in controls and shorter in liver cirrhosis and prothrombin Padua. In conclusion data obtained show that coumarin prothrombin behaves in a different way from cirrhotic prothrombin and also that there is a different behaviour between the two congenital dysprothrombinemias.

Anticoagulants↗
PubMed1984

Effects of low-molecular-weight heparin on platelets as compared with commercial heparin.

Five subjects were injected with 5,000 IU of commercial heparin and low-molecular-weight heparin at an interval of 20 days after each injection. Both heparins produced the same platelet factor 4 release immediately after administration (commercial heparin 114.6 +/- 21.6 ng/ml, low-molecular-weight heparin 113.1 +/- 22.1 ng/ml). However, commercial heparin induced a more evident potentiating effect on ADP-induced platelet aggregation and was still present 60 min after injection. Low-molecular-weight heparin had a higher anti-Xa-specific activity than that determined by activated partial thromboplastin time. The opposite was true for the commercial preparation.

Adenosine Diphosphate↗
PubMed1984

The role of laser nephelometer in the study of abnormal clotting factors: characterization of two abnormal antithrombins (AT III Padua and AT III Padua2).

The immunologic concentration of two abnormal antithrombins III (AT III), namely antithrombin III Padua (AT III Padua) and antithrombin III Padua2 (AT III Padua2) and the kinetics of the reaction of these two ATs III with an anti AT III antiserum was investigated by means of a laser nephelometer. The immunologic concentration of these two AT III both in presence (0.2 IU/mL) or absence of heparin was normal. On the contrary, the analysis of kinetics behavior demonstrated that AT III Padua is radically different from pooled normal plasma both in presence or in absence of heparin. This was not the case for AT III Padua2, which showed no difference from pooled normal plasma regardless of the presence or absence of heparin. Both abnormal antithrombins III reached the plateau of the reaction at about the corresponding value of pooled normal plasma, indicating a normal antigen level. These experimental data were analyzed by means of a computer (Apple II 48 RAM) programmed to solve a four unknowns equation (Rodbard's equation). This analysis showed that the time needed to reach half of the maximum voltage, i.e., the parameter C, which is expressed in minutes, is clearly longer in the case of AT III Padua samples (heparinized or not) as compared with pooled normal plasma. Moreover, the time at which the maximum rate was reached was also longer. On the contrary, in the case of AT III Padua2 there is no difference from pooled normal plasma. These data confirm the view that a different kind of defect is present in these two AT III abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-Antibody Reactions↗
PubMed1984

The contact phase of blood coagulation and renin activation in essential hypertension before and after captopril.

The contact phase of blood coagulation in a group of patients suffering from essential hypertension was studied before and after captopril administration. The baseline levels of factor XII, factor XI and plasminogen were significantly higher than in normals and correlated with baseline diastolic blood pressure levels. On the contrary, plasma prekallikrein was not significantly different from normal. These results suggest the presence of a hypercoagulable state in essential hypertension. After captopril administration, factor XII, factor XI and prekallikrein rapidly decreased, perhaps as a consequence of the drug's effect on the vascular endothelial surface. There was no correlation between the changes of active and inactive renin and the changes of prekallikrein and plasminogen levels. Our data do not support the view that factor XII-plasma kallikrein or plasmin dependent pathways are involved in the activation of inactive renin in vivo. Captopril, by provoking rapid pressure changes, appears to be able to affect the clotting system.

Adult↗
PubMed1984

Effect of atenolol and metoprolol on the anticoagulant activity of acenocoumarin.

In patients receiving long-term acenocoumarin treatment, the effect on anticoagulant activity of atenolol (100 mg once-daily) and metoprolol (100 mg twice daily) was compared in a randomised within-patient open trial. No significant differences were demonstrated between mean prothrombin time and Thrombotest during treatment with atenolol, metoprolol or placebo. These data do not suggest the existence of an interaction between acenocoumarin and the moderately lipophilic beta-adrenoceptor blocker metoprolol, or the hydrophilic beta-adrenoceptor blocker atenolol. The results are discussed in the light of published data for the highly lipophilic beta-adrenoceptor blocker propranolol.

Acenocoumarol↗
PubMed1984

Antithrombin III Trento. A 'new' congenital AT III abnormality with a peculiar crossed-immunoelectrophoretic pattern in the absence of heparin.

A family with a new congenital abnormality of antithrombin III (AT III) is presented. 5 members, all females, were affected. The proposita has had several thrombotic manifestations. The other patients, so far, are asymptomatic. Antithrombin activities were all decreased regardless of the method used (chromogenic or clotting) and regardless of the presence or absence of heparin in the assay system. AT III antigen, on the contrary, was normal in all patients regardless of the method used (electroimmunoassay, radial immunodiffusion or Laser nephelometer). The crossed immunoelectrophoresis without heparin showed in plasma the presence of an abnormal peak which was more anodal than the normal counterpart. The same pattern was seen in serum. In the heparin-modified cross-immunoelectrophoresis a normal pattern was seen in plasma and an abnormal one in serum. In the latter the anodal peak was in fact larger than the normal counterpart. Chromatographic studies using Heparin-Sepharose column failed to show changes in heparin affinity, and indicated that both the normal and the abnormal proposed to describe this abnormality. These studies further emphasize the great heterogeneity of AT III defects. This is the first AT III abnormality to show an abnormal crossed-immunoelectrophoresis in the absence of heparin.

Adult↗
PubMed1984

Clinical significance of beta-thromboglobulin in patients with high platelet count.

The aim of the study was to investigate the relevance of beta-thromboglobulin (beta tg) measurement in patients with thrombocytosis. We have, therefore, studied the level of plasma and platelet beta tg in 74 patients with high platelet count in addition to the evaluation of platelet aggregation and platelet serotonin (5-HT) content. The determinations of platelet serotonin content and aggregation are confirmed to be useful in the differentiation between primary and secondary forms of thrombocytosis. The mean plasma level of beta tg in patients with myeloproliferative disease was significantly raised, but the amount observed in subjects with secondary thrombocytosis is increased too. Considering the amount of beta tg in relation to whole blood platelet count (beta tg ratio), no difference was observed between all patients and controls. The beta tg ratio allowed the identification of a group of patients with an increased ratio and a decreased beta tg platelet content who showed the highest occurrence of thrombosis (66%).

Adult↗
PubMed1984

Blood viscosity studies in native and reconstituted polycythemic blood.

In twelve subjects with Polycythemia vera (P.V.) whole blood, plasma and relative viscosities and the main factors capable of influencing such parameters (Hct, RBCs, WBCs and platelet count, total proteins, gamma-globulins and fibrinogen) were investigated. Ten normal subjects of similar age and sex were studied as control. Whole blood viscosity was determined both in basal conditions and after reconstitution of Hct to normal values by adding some autologous plasma. After the reconstitution of Hct the subjects studied were divided into two groups on the basis of the correlation between Hct and whole blood viscosity. The first group (group A) had a good correlation between Hct and whole blood viscosity; on the other hand the second group (group B) did not show any significant correlation between these two parameters after reconstitution. In basal conditions none of the parameters capable of influencing whole blood viscosity or plasma viscosity permitted any discrimination between the two groups. The relative viscosity, which represents an indirect index of red blood cell deformability, appears to be more elevated in group B. Therefore, the different behaviour of polycythemic blood after reconstitution of Hct might be conceived to be due to a difference in red cell deformability.

Blood Cell Count↗
PubMed1984

Serum of normal subjects contains IgG with antibody-like specificity for phospholipids.

Using counterimmunoelectrophoresis, sera from normal subjects display precipitin activity against liposomes made by phosphatidic acid, phosphatidyl ethanolamine, phosphatidyl serine and cardiolipin. No activity is detected by using liposomes made with phosphatidyl choline, sphingomyelin and phosphatidyl inositol. The same pattern of precipitation is obtained when pure IgG from normal subjects is tested against phospholipids. No precipitin activity is found by using pure IgM. The precipitin reaction is prevented by preincubating liposomes with Fab obtained from normal IgG.

Adolescent↗
PubMed1984

The importance of simple coagulation tests (fibrinogen assays and thrombin coagulase clotting time) in the diagnosis of liver cancer.

Dysfibrinogenemia in 36 patients with primary hepatocarcinoma and in 25 patients with cirrhosis of the liver was studied by means of reptilase time, thrombin coagulase time, fibrin polymerization and fibrinogen assays. Both groups of patients were similar in age, sex and incidence of HBs Ag. No electrolyte or fluid imbalances were present. Prolonged reptilase time and prolonged polymerization time were found in both groups; however, thrombin coagulase time was prolonged in 80% of the hepatocarcinoma group, but was normal in almost all patients with cirrhosis (p less than 0.001). In the hepatocarcinoma group, a difference of more than 100 mg per 100 ml was present between the immunologic and coagulative methods of fibrinogen determination in 36.1% of the cases, but in the cirrhotic group this difference was not present in any of the patients (p less than 0.01). We also found that by simply measuring fibrinogen levels by the Mancini method, we could distinguish hepatocarcinoma from cirrhosis in most cases.

Adult↗
PubMed1984

A microplate enzyme-linked immunospecific assay (ELISA) detecting unbound anti-platelet antibodies.

A microplate immune-enzymatic method was developed for detecting serum antiplatelet antibodies. The method involves the use of antigen-coated platelets and alkaline phosphatase-labeled antihuman immunoglobulin. Linear correlation was obtained between the titer of platelet antibodies and substrate conversion. Twenty-four patients with immune thrombocytopenia and 40 normal controls were studied. Eighteen patients and one control were positive. Therefore, sensitivity and specificity were 75% and 97% respectively. ELISA also was found to be more sensitive than the indirect antiglobulin consumption assay (ACA) and appears to be a practical and easy method for routine evaluation of antiplatelet antibodies.

Binding Sites, Antibody↗
PubMed1983

A family with heterozygous factor X Friuli defect outside Friuli.

Three members of the same family were found to have a clotting defect consistent with the diagnosis of heterozygous factor X Friuli disorder. The main features of the defect were a mild prolongation of prothrombin time and partial thromboplastin time, but a normal Stypven-Cephalin clotting time. Factor X activity was 40-50% of normal using tissue thromboplastin, but was perfectly normal using Russell's viper venom and cephalin. Using chromogenic substrate S-2222 the level was 30% of normal. Immunologically, factor X was normal. Bleeding manifestations were mild if any. The hereditary pattern was autosomal. The family comes from an area far away from Friuli and represents the first example of factor X Friuli discovered outside the Friuli.

Adult↗
PubMed1983

A new family with classical factor X deficiency as demonstrated by electroimmunoassay.

A new family with classical factor X deficiency is described. The proposita is a 6 year old girl who presented with occasional epistaxis and a hematoma after an intramuscular injection. The main laboratory features consisted in a prolongation of partial thromboplastin, prothrombin and Stypven clotting times corrected by the addition of normal serum. Factor X activity varied between 3 and 6%. Factor X amydolytic activity was 15% of normal. Electroimmunoassay failed to show the presence of factor X antigen. No inhibitor was found in the proposita plasma. Parents and other family members showed intermediate levels of factor X activity and antigen and were considered to be heterozygotes. No consanguineity was found in the family.

Antigens↗