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Biomedical subjects

A Girolami

Publications and source records attributed to A Girolami.

At least 235 records · Page 13Linked to original sources
PubMed1994

Prothrombin Padua I: incomplete activation due to an amino acid substitution at a factor Xa cleavage site.

An individual and an affected brother previously identified as having the variant prothrombin Padua I were studied in order to identify underlying genetic defects. A heterozygous mutation in the prothrombin gene exon 8 was identified as substitution of A for G at nucleotide position 7,312 (Arg271 (CGT) to His (CAT)). An abolished RsaI restriction site was used to confirm heterozygosity for the defect. Lack of the requisite cleavage of the His271-Thr272 bond in prothrombin Padua I could prevent release of fragment 2 and block the conversion of the intermediate meizothrombin des fragment 1 to alpha-thrombin, providing an explanation of reduced potential for clotting activity and for the observed mild bleeding tendency.

Amino Acid Sequence↗
PubMed1994

Heterozygous type I plasminogen deficiency is associated with an increased risk for thrombosis: a statistical analysis in 20 kindreds.

The prevalence of thrombosis in patients with heterozygous type I plasminogen deficiency was studied. Fifteen kindreds described in the literature and a further five additional kindreds from the authors' Department were gathered. The prevalence of thrombotic events in all the patients with plasminogen deficiency was 23.6% (22 out of 93 patients), which decreased to 9.5% (seven of 74 patients) when the propositi were excluded. The 95 unaffected siblings were asymptomatic. The comparison between the prevalence of thrombosis in patients with plasminogen deficiency, with or without inclusion of the index patients, and in unaffected family members was statistically significant in both instances (P < 0.0001 and P = 0.002, respectively). Analogous results were obtained from construction of thrombosis-free survival curves, which showed that in plasminogen deficient patients, either with or without inclusion of the propositi, the probability of developing thrombotic manifestations is significantly higher than in unaffected siblings (P = 0.002 and P = 0.043, respectively). It is concluded that congenital heterozygous plasminogen deficiency should be considered a risk factor for thrombosis, even though the probability of having a thrombotic event seems to be lower than in other thrombophilic conditions, such as hereditary defects of clotting factor inhibitors.

Adolescent↗
PubMed1994

Re-evaluation of the therapeutic efficacy of DDAVP in type IIB von Willebrand's disease.

With few exceptions, 1-desamino-8-D-arginine vassopressin (DDAVP) has been shown to be useful in securing haemostasis in patients with von Willebrand's disease (vWd). In type IIB vWd, DDAVP has been reported to have no beneficial effects and to be contraindicated because it causes or worsens thrombocytopenia, due to in vivo platelet aggregation. Nevertheless, it was previously demonstrated that DDAVP may have clinical utility in some patients with type IIB vWd. Additional findings obtained in seven type IIB vWd patients of different kindreds undergoing minor surgical procedures are now reported. It was observed that DDAVP corrected the bleeding time in every case, with effects lasting for 2 h. Mean platelet counts decreased 30 min after DDAVP to variable degrees, depending on the anticoagulant used for blood collection, but were normal 2 h later. Furthermore DDAVP normalized FVIII, von Willebrand factor (vWf) antigen (vWf:Ag), and to a lesser extent, vWf ristocetin cofactor activity (vWf:RCoF). Intermediate and large vWf multimers appeared after 30 min. There were no bleeding complications during or after surgery, nor evidence of thrombosis. It was thus confirmed that DDAVP has clinical utility in the prevention of bleeding symptoms in different type IIB vWd patients. Therefore, despite the transitory thrombocytopenia and the incomplete restoration of larger vWf multimers, the use of this drug should be reconsidered for patients with type IIB vWd.

Deamino Arginine Vasopressin↗
PubMed1994

Essential thrombocythemia and pregnancy: a report of six normal pregnancies in five untreated patients.

OBJECTIVE: To report our experience with essential thrombocythemia complicating pregnancy. METHODS: Over a 5-year period, we studied 21 women of reproductive age affected by essential thrombocythemia. Diagnoses were based on previously published Polycythemia Vera Study Group criteria. RESULTS: Five of our 21 patients became pregnant (total six pregnancies). All pregnancies were carried to term, with uncomplicated deliveries of normally formed infants. No thrombotic or hemorrhagic complications were encountered. CONCLUSION: Normal pregnancy and delivery is readily possible in patients with essential thrombocythemia.

Adult↗
PubMed1994

Specific antiplatelet autoantibodies in patients with antiphospholipid antibodies and thrombocytopenia.

By means of immunoblotting and monoclonal antibody immobilization of platelet antigens (MAIPA) we have studied the specificity of antiplatelet antibodies in patients with antiphospholipid antibodies and thrombocytopenia defined as presence of anticardiolipin IgG and a platelet count below 100 x 10(9)/l. The study group consisted of 10 patients with systemic lupus erythematosus (SLE), 8 patients with primary anti-phospholipid syndrome (PAPS) and 16 patients with idiopathic thrombocytopenic purpura (ITP). The comparison group was formed by 17 patients with classical chronic ITP without anticardiolipin IgG. We identified the 80-100, 130-150 and 150-170 KD surface proteins that comigrate with GPIIIa, GPIIb and GPIb and a 50-70 KD cytoplasm band by immunoblot. In patients with classical chronic ITP, the prevalence of the antiplatelet antibodies against GPIIIa was 53% on immunoblot assay and 47% on MAIPA. In ITP patients who had also anti-phospholipid antibodies in serum, the percentage of reactivity to GPIIIa declined to 37% on immunoblot and 21% on MAIPA but it was not statistically different from the percentage observed in patients with classical ITP. Autoantibodies to platelet surface glycoproteins were almost absent in SLE and PAPS patients, who showed a significant prevalence (78%) of IgG reactivity to the 50-70 KD internal platelet protein which was frequently encountered also in patients with ITP and aPL (56%). Our study provides additional evidence that platelet antigens in patients with phospholipid-associated secondary immune thrombocytopenia are different from those of primary ITP, and that surface glycoproteins were not involved.

Adult↗
PubMed1994

EDTA dependent pseudothrombocytopenia caused by antibodies against the cytoadhesive receptor of platelet gpIIB-IIIA.

AIMS: To clarify the mechanisms involved in the development of EDTA dependent pseudothrombocytopenia, particularly the platelet receptors. METHODS: Platelets were measured in 33 patients with pseudothrombocytopenia, using different anticoagulants to collect blood samples (direct test). The results were compared with the counts obtained by adding patients' serum or immunoglobulins to normal blood samples (indirect test). The role of platelet function was explored using ASA, PGE1, and apyrase as platelet inhibitors. The contribution of platelet receptor/s was investigated using antigens to gpIb-IX and gpIIb-IIIa monoclonal antibodies. Immunoglobulin class was estimated by the ability of IgG, IgA, and IgM antibodies to prevent platelet clumping. RESULTS: Agglutinating antibodies were IgA in 40%, IgG in 30%, and IgM in 10% of patients studied. Both patients' serum and immunoglobulins induced platelet clumping in normal samples anticoagulated with EDTA (indirect test). This was prevented by incubation of blood samples at 37 degrees C and almost completely inhibited by the platelet inhibitors ASA, PGE1, and apyrase. Pseudothrombocytopenia was also entirely prevented by an antigen to gpIIb-IIIa monoclonal antibody that recognises fibrinogen and the von Willebrand factor binding site. Pseudothrombocytopenia was almost completely abolished after the addition of RGD peptide, the recognition sequence of cytoadhesive proteins. CONCLUSIONS: These findings suggest that EDTA dependent pseudothrombocytopenia is caused by agglutinating antibodies that recognise cytoadhesive receptors on platelet gpIIb-IIIa and that an efficient platelet metabolism is required.

Adult↗
PubMed1994

Acquired factor VIII:C inhibitor in a patient with Sjögren's syndrome: successful treatment with steroid and immunosuppressive therapy.

A 57-year-old woman affected with Sjögren's syndrome without bleeding history developed spontaneous hematomas at the arms, the left foot and the thigh, cutaneous hemorrhages and hematuria. Routine coagulation tests showed a prolongation of activated partial thromboplastin time associated with a marked reduction of factor VIII activity (VIII: C 5%). Other deficiencies of blood coagulation factors, especially von Willebrand factor, were excluded. Measurement of factor VIII inhibitor revealed an activity of 26.4 Bethesda units/ml. These findings were consistent with the diagnosis of acquired hemophilia A due to the presence of a factor VIII inhibitor. The patient was treated with a combination of prednisone and azathioprine. The therapy led, in a few months, to a significant reduction of factor VIII: C inhibitor and she did not require replacement therapy. Furthermore, there was a complete remission of the bleeding tendency. Long-term therapy for about 3 years induced the complete disappearance of the inhibitor and a full normalization of coagulation tests.

Arm↗
PubMed1994

Changing features of proximal vein thrombosis over time.

Recently, the sensitivity of impedance plethysmography (IPG) for the diagnosis of acute deep-vein thrombosis (DVT) in symptomatic outpatients has been questioned. In order to verify whether a change in the venographic pattern of DVT has occurred over years, accounting for the decreased sensitivity of IPG, the authors compared two series of consecutive venograms demonstrating proximal DVT, performed between 1984-1988 (166 patients) and 1990-1992 (140 patients). They evaluated both the extension and the occlusiveness of deep-vein thrombi in the two series. Moreover, changes in the referral characteristics of patients were investigated. In the second series of venograms a significant decrease in thrombi extension, expressed by a lower prevalence of iliac vein thrombosis (29% versus 43%; P = 0.0074) was observed; moreover, a significant increase in the prevalence of nonocclusive thrombi (22% versus 8%; P = 0.0004) was also recorded in the second series when compared with the first. During the study period, among the referral characteristics of patients, the authors observed both a significant decrease in the prevalence of proximal DVT (from 31% to 24%; P < 0.01) and a slight and not statistically significant decrease in the median time elapsed between onset of symptoms and referral for objective testing (from eight and a half to seven days). In conclusion, proximal deep-vein thrombi are currently less extensive and occlusive than observed in the past. These results might depend on earlier referral of less symptomatic patients and might explain the recently reported decrease in IPG sensitivity for proximal DVT.

Analysis of Variance↗
PubMed1994

Post-polycythemia myeloid metaplasia: experience with a large cohort of patients.

The common origin of myeloproliferative disorders can explain the possible evolution of polycythemia vera to post-polycythemia myeloid metaplasia (PPMM). Such a possible event is usually considered linked to the use of myelosuppressive agents in particular 32P. Occasionally, myelofibrosis following essential thrombocythemia has also been described. We report here 19 cases of post-polycythemia myeloid metaplasia out of 214 polycythemia vera patients (8.8%). The majority of these patients received 32P therapy. However, busulfan also seems to have some role in the modification of polycythemia vera. In particular, the association of more than one myelosuppressive agent may favour the evolution of PPMM.

Adult↗
PubMed1994

Symptomatic versus asymptomatic patients in congenital hypoplasminogenemia: a statistical analysis.

In the present study, the prevalence of thromboembolic events in patients suffering from type I plasminogen deficiency was evaluated. One hundred and twelve affected subjects belonging to twenty-eight kindreds were gathered from the literature and from personal observations. The incidence of thrombosis found in this group was compared with those seen in: a) 86 unaffected family members; b) 100 hospitalized patients; c) 100 outpatient clinic patients. In the latter two groups, congenital clotting disorders were excluded. Thrombotic manifestations were found in 25.8% of patients with plasminogen deficiency, a figure which was statistically different from those found in unaffected family members (1.16%, p < 0.001), hospitalized patients (3%, p < 0.001) and outpatient clinic patients (5%, p < 0.001). In twenty-four kindreds with hypoplasminogenemia, data concerning the actuarial ages at first thrombotic event were available for construction of thrombosis-free survival curves by the Cutler-Ederer method. The difference between the two curves, corresponding to affected and unaffected family members respectively, were statistically significant (p < 0.01). In conclusion, although the incidence of thromboembolic events in type I plasminogen deficiency is certainly lower than that described in other congenital clotting disorders such as AT III, protein C and protein S, patients with hypoplasminogenemia should be considered at risk for thrombosis, particularly when triggering factors are present.

Family Health↗
PubMed1994

A new variant of von Willebrand's disease (type I Padua): doublet-organized plasma von Willebrand factor oligomers in the presence of all size multimers.

Type I von Willebrand's disease (vWd) is characterized by a concomitant decrease in plasma of von Willebrand factor antigen (vWf:Ag) and vWf ristocetin cofactor activity (vWf:RCoF), associated with the presence of all-size multimers. As a rule, there is no evidence of intrinsic abnormality in vWf. We describe a family with type I vWd with an abnormal plasma vWf multimer pattern. Analysis of plasma vWf multimeric structure by short-SDS-agarose gel electrophoresis showed an abnormal banding pattern for each vWf oligomer, which was organized as a doublet instead of the normal triplet. The electrophoretic mobility of each component appeared to be normal. Multimeric analysis on a long gel showed all the bands that were detectable in normal subjects, but unlike normals the fast moving satellite stained as the major component. The platelet vWf multimer pattern was normal. The infusion of DDAVP normalized vWf:Ag, vWf:RCoF and VIII:C, but not the abnormal multimer pattern observed on both short- and long-gel electrophoresis. The return of factor VIII/vWf complex to the baseline condition was more rapid than that observed in normal subjects or classic type I vWd patients. Analysis of the subunit fragments in the patients' plasma vWf demonstrated a relatively greater proportion, compared to the normal counterpart, of a 115(140)-kD fragment, which derives from the aminoterminal region of the mature molecule; in contrast, no intact subunit was detectable. These findings indicate a new, previously unreported, variant of type I vWd, which is characterized by plasma vWf oligomers organized as doublets, instead of triplets. The reduced post-DDAVP half-life, and the abnormal subunit fragments of vWf, suggest a molecule characterized by an increased susceptibility to proteolytic degradation. As a result, the decrease in circulating vWf levels may be due to an instability of the abnormal vWf, rather than, or in addition to, a decrease in its synthesis.

Adult↗
PubMed1994

Report on a 3-year follow-up zidovudine (AZT) treatment in a group of HIV-positive patients with congenital clotting disorders.

Eleven (50%) of 22 HIV-seropositive patients suffering from congenital coagulation defects and followed at the Hemophilia Center of Padua met the eligibility criteria for zidovudine (AZT) therapy. A 3-year clinical and laboratory follow up is described. Mean length of AZT treatment was 14.3 +/- 11 months. Three patients were enrolled at the latest stages (CDC stage IV) of HIV disease. They showed no clinical improvement after AZT administration and died with AIDS. One CDC stage III patient died from a high-grade non-Hodgkin's lymphoma (NHL) which suddenly developed 3 months after starting AZT. Seven patients began antiretroviral treatment when they were mild or asymptomatic for HIV infection (CDC stage II and III). None developed any sign of HIV disease progression on the basis of CDC criteria. Moreover, AZT administration induced an improvement of the humoral markers related to HIV disease, as CD4 T-lymphocyte count, serum beta 2-microglobulin (B2M) and, although only for few months, neopterin (Np) levels. A mild thrombocytopenia due to HIV infection was detected in 5 patients. In all cases AZT treatment was effective in increasing and/or normalizing the platelet count. Reduced daily dose AZT (600-500 mg/day) appeared to be well tolerated and of minimal toxicity as compared to the higher dose (1200 mg/day). In our study, the zidovudine-induced bone marrow suppression, namely severe anemia or pancytopenia, was the major side-effect limiting tolerance of the higher dose AZT.

Adolescent↗
PubMed1994

Microheterogeneity of antithrombin III: effect of single amino acid substitutions and relationship with functional abnormalities.

Microheterogeneity of antithrombin III (AT-III) was investigated by crossed immunoelectrofocusing (CIEF) on eleven molecular variants. A normal pattern was found in five variants while two different abnormal CIEF patterns were found in the other four and two variants, respectively. Point mutations causing a major pI change (exceeding 4.0) of the amino acid substituted lead to alterations in the overall microheterogeneity. The variants thus substituted share a first type of abnormal CIEF pattern with alterations throughout the pH range, regardless of the location of the mutation (reactive site and adjacent regions or heparin binding region). Minor amino acid pI changes in these regions do not alter the AT-III overall microheterogeneity, whatever the resulting functional defect. However, if the mutation is placed in the region around positions 404 or 429, then even minor changes of the amino acid pI seem able to alter the overall charge, leading to a second type of abnormal CIEF pattern with the main alteration at pH 4.8-4.6. Neuraminidase treatment leads to disappearance of microheterogeneity except for the variants with the Arg393 to Cys substitution. Addition of thrombin induces CIEF modifications specifically related to the functional defect. A normal formation of thrombin-antithrombin complexes induces a shift towards the more acid pH range, whereas in the variants substituted at the reactive site the CIEF pattern is substantially unaffected by thrombin; variants substituted at positions 382-384 show a maximal thrombin-induced increase of the isoforms at pI 4.8-4.6. Therefore mutant antithrombins with different functional abnormalities but sharing a common CIEF pattern were well distinguished.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗