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Biomedical subjects

A Girolami

Publications and source records attributed to A Girolami.

At least 415 records · Page 23Linked to original sources
PubMed1985

The evaluation of factor VIII antigen by means of a simple slide test.

Factor VIII von Willebrand may be detected by a Ristocetin-dependent platelet agglutination reaction. The authors have measured plasma levels of Factor VIII-related Ristocetin cofactor (VIIIR:RCoF) using formalin-fixed platelets tested by an aggregometric method or by a new, commercially available glass slide test. Plasmas were obtained from patients with von Willebrand's disease and Cushing's syndrome, and from normal controls. Von Willebrand factor (vWf) levels varied between 0-500% of the normal. A good correlation (r = 0.95) was found comparing the results obtained by the two methods over the entire range. If all patients were considered, a satisfactory correlation was obtained between VIIIR:RCoF and VIII-related antigen (VIIIR:Ag), both by the aggregometric method (r = 0.79) and by the glass slide method (r = 0.88). On the contrary, if values below 25% of the normal are taken into account, only a mild correlation was found between VIIIR: RCoF (aggregometric method) and VIIIR:Ag and no correlation between VIIIR:RCoF (glass slide method) and VIIIR:Ag. No correlation, regardless of the method used, was found between VIIIR:RCoF and VIIIR:Ag for values above 120%.

Antigens↗
PubMed1985

Fibrinolytic study in plasma and ascitic fluid of cirrhotic patients before and after ascites concentration; reinfusion technique.

Management of cirrhosis with massive ascites involves particular difficulties. The introduction of a peritoneovenous shunt and reinfusion of concentrated ascitic fluid techniques allows increased diuresis and improves renal function. However, these procedures have frequently been associated with disseminated intravascular coagulation and/or activation of fibrinolysis. Factor VIII activity, antigen and ristocetin cofactor, plasminogen, antiplasmin, plasminogen activator activity and plasmin-antiplasmin complex were investigated both in the ascitic fluid and plasma of cirrhotic patients before and after the concentration-reinfusion technique. Our results indicated that no hyperfibrinolysis was seen in the plasma of cirrhotic patients and that activation of fibrinolysis exists in ascites. Significantly higher levels of plasmin-antiplasmin complex and plasminogen activator activity were found in ascitic fluid than in plasma. In post-reinfusion much higher levels of all three Factor VIII components were observed in cirrhotic plasma than in normal plasma. In conclusion, activation of fibrinolysis could explain coagulation complications occurring after ascites reinfusion. Antifibrinolytic treatment could render the concentration-reinfusion technique more acceptable.

Adult↗
PubMed1985

Effect of heparin and aspirin on platelet and clotting activation during leukapheresis.

Beta-thromboglobulin (beta TG), serotonin (5HT) and fibrinopeptide A (FPA) were assessed in twenty-two normal donors before, during, and at the end of leukapheresis. Seven procedures were carried out adding heparin to the circuit, and seven adding acetyl salicylic acid (ASA). The remaining eight procedures were carried out using only citrate and served as controls. Plasma beta TG increased both during and after the apheresis, together with a significant decrease of the intra-platelet content. Platelet 5HT did not show significant changes whereas FPA increased significantly. Using heparin, we obtained a complete prevention of FPA cleavage during the entire procedure, while beta TG increased at the middle of the procedure. No significant effects were observed using ASA both on beta TG and FPA levels. These features clearly indicate the activation of platelets and the thrombin generation in the apheresis circuit. Nevertheless, the activation of the clotting system seems to be predominant, as supported by the improved effect of heparin on beta TG and FPA amounts.

Adult↗
PubMed1985

PF 4 versus beta TG as evidence for platelet activation in myeloproliferative disorders.

19 patients with MPD have been studied. As described in normals, an age-related increase in beta thromboglobulin (beta TG) release is observed. Such release, however, is greater in patients with myeloproliferative disorders (MPD). MPD seem therefore to cause platelet activation, allowing an earlier and more evident manifestation of physiologic ageing phenomena. PF 4 levels are near zero both in controls and patients, regardless of platelet number. This suggests that increased levels of PF 4 represent only a laboratory artifact, caused by platelet activation in vitro. Mean ability in producing thromboxane B2 (TxB2) is increased, but is perfectly normal in patients with normal platelet count and decreased in 3 thrombocythaemic patients, who seem to present an increased thrombotic risk. TxB2 is reduced almost to zero by the administration of aspirin plus dipyridamole; contrarily, all other parameters were unaffected, either by such drugs or by AD 6, a new coumarin derivative with antiplatelet properties.

Adult↗
PubMed1985

Factor X Padua: a 'new' congenital factor X abnormality with a defect only in the extrinsic system.

A family with a new factor X defect is reported. The proposita is a 56-year-old female. She is asymptomatic and no consanguinity is present between the parents. The main features of the defect are: prolongation of prothrombin time and derivative tests but normal partial thromboplastin time. Factor X was found to be low (about 25-30% of normal) only if tissue thromboplastins were used in the assay system. Chromogenic substrate S-2222 also yielded decreased factor X levels. However, factor X activity was normal with cephalin and cephalin-RVV mixture. Factor X antigen was normal in three immunological systems (electroimmunoassay, an Elisa method and laser nephelometry). Crossed immunoelectrophoresis and antigen-antibody kinetics recorded in a laser nephelometer failed to show major differences from normal factor X. Both sons of the proposita, the father and other family members showed slightly decreased factor X levels and normal factor X antigen and were considered heterozygous for the abnormality. The toponym factor X Padua is proposed to indicate this peculiar abnormality.

Factor X Deficiency↗
PubMed1985

Interaction of asialo von Willebrand factor with glycoprotein Ib induces fibrinogen binding to the glycoprotein IIb/IIIa complex and mediates platelet aggregation.

von Willebrand factor (vWF) is necessary for the initial attachment of platelets to exposed subendothelium, particularly under flow conditions like those prevailing in the microcirculation. Little is known about its possible participation in subsequent events leading to formation of platelet thrombi at sites of vascular injury. We addressed this question by studying the mechanisms by which desialylated vWF induces platelet aggregation in the absence of any other stimulus. Asialo vWF, unlike the native molecule, does not require ristocetin to interact with platelets. Agglutination induced by ristocetin is largely independent of active platelet metabolism and only partially reflects physiological events. We have shown here that binding of asialo vWF to platelets was accompanied by release of dense granule content and subsequent ADP-dependent fibrinogen binding to receptors on the glycoprotein (GP) IIb/IIIa complex. The initial interaction of asialo vWF with platelets was mediated by GPIb, as shown by blocking obtained with monoclonal antibody. Inhibition of this initial interaction completely abolished platelet aggregation induced by asialo vWF. The same effect was obtained with a monoclonal anti-GPIIb/IIIa antibody. This, however, did not block asialo vWF binding to platelets, but rather inhibited subsequent fibrinogen binding induced by asialo vWF. Therefore, the latter process was also essential for platelet aggregation under the conditions described. At saturation, asialo vWF induced binding of between 3.2 and 27.7 X 10(3) fibrinogen molecules/platelet, with an apparent dissociation constant between 0.28 and 1.18 X 10(-6) M. This study shows that asialo, and possibly native, vWF acts as a platelet agonist after its binding to GPIb and induces aggregation through a pathway dependent on GPIIb/IIIa-related receptors.

Asialoglycoproteins↗
PubMed1985

Excess of factor X antigen versus clotting counterpart in coumarin treated patients as determined by an Elisa method.

Factor X antigen was assayed by means of an Elisa (sandwich) method in 36 patients on long-term anticoagulant therapy. The average value observed was 31.4% +/- 12.2. In almost every instance the antigen level was higher than the clotting counterpart (14.4% +/- 4.5). In a few instances no major difference was noted between factor X antigen and factor X activity. The method correlated fairly well with other immunological methods (electroimmunoassay and Laser Nephelometer). Therefore, factor X Elisa method appears to be a suitable method for factor X antigen evaluation.

Antigens↗
PubMed1985

Contact phase of coagulation in diabetes mellitus after aspirin administration.

The purpose of our study was to investigate the connection between platelets and the contact phase of coagulation. In 17 patients affected by diabetes mellitus we studied the behaviour of prekallikrein, factor XII and factor XI before and after aspirin administration. To evaluate the activity of aspirin we measured platelet production of thromboxane B2 using a radioimmunoassay. In our diabetic patients a hypercoagulable state was confirmed: PK, factor XII and XI levels were significantly higher as compared with normal controls. After aspirin administration a significant decrease of PK levels was found. After 7 days of aspirin administration and 7 days after stopping aspirin a modest but not significant improvement of factor XII and factor XI was observed. In conclusion, we believe that the contact phase of coagulation is another index of the hypercoagulable state in diabetes mellitus. In addition, the decrease of PK obtained by aspirin administration could support the possible connection between the contact phase of coagulation and platelets.

Aspirin↗
PubMed1985

Antithrombin III deficiency: a report of 14 cases belonging to three different kindreds.

A hereditary deficiency of AT III is described in 14 subjects belonging to three different kindreds. There is no consanguineity in any of the families investigated. The pattern of inheritance of defect appears autosomal dominant. Seven of the affected subjects presented thrombotic episodes (deep vein thrombosis, splanchnic thrombosis, pulmonary embolization). The main laboratory features were: normal routine clotting tests, decreased AT III activity in all assay systems and concomitantly reduced AT III antigen levels. Crossed immunoelectrophoresis showed only reduced peaks with respect to normal in both plasma and serum. No correlation was found between age of patients and AT III levels.

Adult↗
PubMed1985

Haemorheological parameters in alopecia areata.

Whole blood, plasma and relative viscosities and red cell filterability have been investigated in 15 patients with Alopecia areata (A.A.) and in 9, age and sex-matched, normal subjects. Erythrocyte filtration time resulted to be significantly increased in alopecic subjects as compared to the normal subjects. Such parameter also showed a good correlation (r = 0.752) with relative viscosity. Whole blood, plasma and relative viscosities were not significantly different from normal subjects.

Adolescent↗
PubMed1985

The use of laser-nephelometry in evaluating fibrinogenaemia in patients with hepatocarcinoma and cirrhosis.

In the present study fibrinogen was assayed by the immunonephelometric method in 19 patients afflicted with hepatocarcinoma and 24 patients afflicted with cirrhosis. The two groups were similar in age, sex and presence of HbsAg. The incidence of values above the norm was significantly greater in patients with hepatocarcinoma (p less than 0.05). Then, the concentration of fibrinogen was measured in all using two other immunological methods (Laurell and Mancini) and two coagulative methods (Clauss and Ratnoff). A dysfibrinogenemia (an excess of fibrinogen assayed by immunological methods to be greater than 100 mg/dl with respect to biological methods). is more frequent using the Nephelometer-Clauss (p less than 0.01) and Mancini-Clauss (p less than 0.01) methods in patients with hepatocarcinoma with respect to those with cirrhosis. The study of the kinetics of antifibrinogen antigen-antibody reaction failed to show differences between patients with hepatocarcinoma or cirrhosis and normal subjects.

Carcinoma, Hepatocellular↗
PubMed1985

The effect of different doses of 32P in the treatment of primary thrombocytosis.

We report on a follow up in 23 patients with primary thrombocytosis treated with two different doses of 32phosphorus phosphate (32P). Ten patients with essential thrombocytosis (ET) received 2 mCi and 13 patients with polycythemia vera (PV) received the standard dose of 0.1 mCi/kg b.w. The patients were listed as having a complete response (CR), partial response (PR) or no response (NR) considering platelet count at 3 and 12 months after 32P injection. The results indicate the existence of a clear correlation of the rate of remission with the 32P injected dose. PV patients show, in fact, a percentage of complete remission higher than ET patients. However, the use of higher doses induces more early and long-term complications.

Adult↗
PubMed1985

Behaviour of antithrombin III abnormalities in the crossed immunoelectrophoresis system.

Antithrombin III (AT III) abnormalities can be characterized by means of crossed immunoelectrophoresis. In the past, it was thought that the abnormalities could be demonstrated only if heparin is present in the system. Now some conditions (AT III Trento, for example) are known to show an abnormal pattern only in the absence of heparin. This indicates that some of the changes are heparin-independent. Furthermore, it could be demonstrated that in some cases the abnormality is present only in serum (AT III Vicenza, for example). Therefore, the test should be carried out as a screening procedure both in plasma and serum and in the presence or absence of heparin in every case of suspected AT III abnormality.

Antithrombin III↗
PubMed1985

Platelet factor 4 release induced by intravenous administration of heparin.

When heparin is injected intravenously, it can induce an immediate release of platelet factor 4 PF4), probably from the non-platelet pool of endothelial cells. We evaluated this release in a group of normal subjects and patients with cardiovascular disorders or thrombocytosis after an intravenous injection of a bolus of 5,000 I.U. of a commercial mucous heparin. The mean level in normals was 102 +/- 32 (range 50-160) ng/ml and no correlation was found before and after heparin injection between PF4 and heparin level, body weight or platelet count. Only three cardiovascular patients had an elevated level of PF4 released by heparin (HR-PF4) that could be the expression of an increased platelet turnover, whereas all the patients with thrombocytosis had an extremely elevated level of HR-PF4. These patients have much more PF4 available for the binding sites of endothelial cells since only a small percentage of potential binding sites are normally occupied "in vivo". Although no correlation could be found between platelet count and HR-PF4 in subjects with a normal platelet count or in patients with thrombocytosis there was a positive correlation, however, when all the cases were considered together. The other proteins with heparin affinity, B-thromboglobulin, antithrombin III and fibronectin were not influenced by a bolus of heparin and did not correlate in normals as well in patients with HR-PF4.

Adolescent↗
PubMed1985

Effects of ticlopidine on blood fibrinogen and blood viscosity in peripheral atherosclerotic disease.

Ten patients with peripheral atherosclerotic disease(PAD) treated with 750 mg/d of 5-(2-chlorophenylmethyl)-4,5,6,7-tetrahydrothieno (3,5-c-pyridine) hydrochloride (ticlopidine, Tiklid) were studied for three months. As control was studied a similar group of patients treated with a traditional vasodilator (nicotinate). The aim of our study was to evaluate the effect of ticlopidine both on the clinical evolution of the disease and on rheologic, coagulative and platelet parameters. A progressive increase of maximal walking distance was noted during the three months of therapy with ticlopidine and limited to the first 30 days of treatment with nicotinate. The fibrinogen levels resulted significantly lowered during 90 days of treatment with ticlopidine, while that was not evident in the nicotinate group. There was also a slight improvement of blood viscosity in the ticlopidine group (not evident in the nicotinate group), but it was not statistically significant. No further modifications of investigated data were found in the two groups of patients. The clinical benefit of ticlopidine in PAD without adverse reactions can be confirmed at least at the dosage of 750 mg/d instead of the usual dose of 500 mg/d. A direct or indirect action of ticlopidine on plasma fibrinogen is suggested. This observation may supply new clues for the understanding of the mechanism of action of this drug.

Aged↗