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Biomedical subjects

A Girolami

Publications and source records attributed to A Girolami.

At least 253 records · Page 14Linked to original sources
PubMed1993

Platelet aggregation induced by plasma from type IIB von Willebrand's disease patients is associated with an increase in cytosolic Ca2+ concentration.

The effect of type IIB von Willebrand's factor (vWF) on platelet cytosolic Ca2+ ion concentration, measured by means of the probe fura 2, was investigated. Seven patients with type IIB von Willebrand disease (vWD) were studied. Addition of type IIB vWD plasma to platelet suspensions induced a cytosolic calcium increase accompanied by platelet aggregation. Both processes were completely abolished by addition of the calcium-chelating agent EGTA, indomethacin, peptide RGDS, and monoclonal antibodies blocking the vWF binding site on GPIb-IX (LJIB1) or the cytoadhesive receptor on GPIIb-IIIa (LJCP8). The ADP-scavenger apyrase and the protein kinase C-inhibitor staurosporine partially inhibited the rate of the cytosolic calcium increase. No direct correlation between the extent of Ca2+ rise and the phenotypic expression of IIB vWD, such as the degree of spontaneous platelet aggregation or thrombocytopenia was apparent. It is suggested that aggregation and cytosolic Ca2+ increase in platelets exposed to plasma from type IIB vWD patients is mediated by a self-potentiating mechanism involving both GPIb and GPIIb-IIIa receptors as well as the thromboxane biosynthetic pathway.

Amino Acid Sequence↗
PubMed1993

Comparison of real-time B-mode ultrasonography and Doppler ultrasound with contrast venography in the diagnosis of venous thrombosis in symptomatic outpatients.

In a prospective study, we compared real-time B-mode ultrasonography, using the simple criteria of common femoral and popliteal vein compressibility (Compression US), and Doppler ultrasound, using a standardized technique (Doppler US), with contrast venography in 158 consecutive outpatients symptomatic for deep-vein thrombosis of the lower limbs (DVT). For proximal vein thrombosis, the sensitivities documented for Compression US and Doppler US were 100% (95% CI: 90% to 100%) and 89% (95% CI: 76% to 96%), respectively. This difference is not statistically significant (p = 0.056). For all thrombi (including isolated calf-vein thrombosis), however, the sensitivity of Compression US was significantly higher than that of Doppler US (95% and 76%, respectively; p < 0.04). Compression US was normal in all patients with normal venogram (specificity, 100%; 95% CI: 95% to 100%), while Doppler US was abnormal in two patients with normal venogram (specificity, 98%; 95% CI: 92% to 100%). The specificities of the two tests did not differ significantly. The results of our comparison suggest that Compression US is superior to Doppler US in the detection of DVT in symptomatic outpatients.

Adult↗
PubMed1993

The dysfunction of coagulation factor VIIPadua results from substitution of arginine-304 by glutamine.

This study addresses whether a mutation in the factor VIIPadua gene could explain the reduced activity of the inherited variant protein. All nine exons of the normal and Padua factor VII gene were amplified using the polymerase chain reaction, cloned into pUC19 and sequenced. A point mutation (G to A at nucleotide position 10828) was found which results in the substitution of a glutamine (CAG) for arginine (CGG) at amino acid position 304. This substitution creates a PvuII restriction site useful in screening for the defect and in demonstrating homozygosity. This substitution involves an arginine residue in the catalytic domain within a Leu*****Pro******Cys motif which occurs in conserved region 5 in up to 16 coagulation and other serine proteinases. On the basis of conformational homology among serine proteinases, it is suggested that the observed amino acid substitution in factor VIIPadua could cause structural changes affecting its activation and/or catalytic activity.

Amino Acid Sequence↗
PubMed1993

A novel dysfunctional protein C (protein C Padua 2) associated with a thrombotic tendency: substitution of Cys for Arg-1 results in a strongly reduced affinity for binding of Ca++.

A dysfunctional protein C (PC) molecule (Protein C Padua 2) was found in a 40-year-old man presenting with recurrent deep vein thrombosis/pulmonary embolism and a family history of thrombotic disease. The patient exhibited a normal PC antigen level, normal chromogenic activity (using Protac as PC activator) but markedly reduced coagulometric activity. After adsorption of patient plasma onto Al(OH)3, between 30% and 45% PC antigen/chromogenic activity but no coagulometric activity was detectable in the supernatant. The dysfunctional molecule exhibited reduced affinity for a Ca++ dependent anti-protein C monoclonal antibody as detected by specific ELISA assay. Immunoblotting experiments showed that PC Padua 2 had an increased MW (95 kD v 65 kD for normal PC). The lesion responsible was determined by PCR/direct sequencing to be a heterozygous CGT/TGT transition in exon 3 of the protein C gene resulting in the substitution of Arg by Cys at residue--1 in the pro-peptide leader sequence. The presence of a high MW PC was consistent with the fact that (part of) the propeptide (at least Cys-1) still was attached to the protein C molecule. This finding could also explain the strongly reduced affinity of PC Padua 2 for the Ca++ dependent anti-protein C monoclonals.

Adult↗
PubMed1993

Unusual thrombotic-like retinopathy (Coats' disease) associated with congenital plasminogen deficiency type I.

A new kindred with heterozygous plasminogen deficiency type I is described. The proband, a 17-year-old male, showed a peculiar thrombotic-like retinal picture compatible with Coats' disease. Extensive coagulation studies revealed decreased levels of both plasminogen activity and antigen to about 50% of normal values. Five out of 13 family members from the paternal side showed the same fibrinolytic defect. In two cases, a history of recurrent phlebites of the lower limbs was present. One unaffected patient also had a superficial phlebites at a young age; her plasminogen levels were shown to be within normal limits, but a long-standing oestroprogestinic intake could have influenced and normalized the results. No other family member showed retinal abnormality. This is the first case of hypoplasminogenaemia associated with Coats' disease. A possible role of the fibrinolytic defect in the pathogenesis of this unusual retinopathy is suggested. Finally, the occurrence of thrombotic manifestations in other affected family members supports the opinion that plasminogen deficiency should be considered as a potential risk factor for thrombosis.

Adolescent↗
PubMed1993

A simple ultrasound approach for detection of recurrent proximal-vein thrombosis.

BACKGROUND: The objective of this study was to develop a simple ultrasound method for measuring thrombus regression in patients with proximal deep-vein thrombosis (DVT) and to test its utility for the detection of DVT recurrence. METHODS AND RESULTS: The study comprised a cross-sectional survey and a prospective investigation (149 and 145 patients, respectively). In both phases, the normalization rate of a previously abnormal ultrasound test, applying the criterion of full compressibility of the common femoral and popliteal veins (C-US method), was assessed. In the prospective study, the vein diameter under maximum compression (thrombus thickness) was measured in the abnormal venous segments at scheduled times (1, 3, 6, and 12 months). In patients presenting with suspected DVT recurrence, the procedure was repeated and results were compared with those available from the previous examination. Noncompressibility of a previously normal(ized) venous segment and enlargement of thrombus thickness (> or = 2 mm) were considered diagnostic of proximal DVT recurrence. The diagnostic accuracy of the C-US method alone, as well as of the combined ultrasound methods (C-US + thrombus thickness), was assessed against contrast phlebography. C-US test normalization occurred in only 30% of patients within 1 year. A significant reduction of the thrombus mass (P < .0001) was recorded throughout the entire study period. However, a major decrease in thrombus mass (> 50%) was recorded within the first 3 months. Of 29 patients who developed a suspected recurrent DVT, phlebography confirmed diagnosis in 11. The C-US method alone showed an excellent accuracy (100%) but was applicable in only 6 patients (21%). Both the sensitivity and the specificity for proximal DVT recurrence of the combined ultrasound methods were 100% (95% confidence interval, 69% to 100% and 81% to 100%, respectively) and were applicable in all patients. CONCLUSIONS: The serial ultrasound measurement of thrombus mass after an acute episode of DVT may allow the correct identification of patients who develop a recurrent proximal-vein thrombosis.

Cross-Sectional Studies↗
PubMed1993

The effect of a single course of alpha-2B-interferon in patients with HIV-related and chronic idiopathic immune thrombocytopenia.

13 patients with HIV-related immune thrombocytopenia (HIV-ITP) and 10 patients with chronic idiopathic thrombocytopenic purpura (C-ITP) were treated with a single course of alpha-2b-Interferon (IFN 3 x 10(6) IU subcutaneously for 12 d). The patients had platelet counts lower than 40 x 10(9)/L and thrombocytopenia persisting for over 1 year (range 1-22 years); 7 patients were refractory to previous conventional therapy, 5 were responsive, and 11 had not been previously treated. The response to IFN was complete in 8 patients (platelets > 100 x 10(9)/L), partial in 7 (platelets 50-100 x 10(9)/L); 8 patients showed no response. The treatment with IFN was stopped after 4 d in one patient due to a fall in platelet count. The maximal platelet count (median peak 116 +/- 55 SD x 10(9)/L platelets) was obtained after 13.7 +/- 2.98 d and the improvement in platelet count was maintained for 22.8 +/- 8.6 d. No difference in platelets response was observed between HIV-ITP and C-ITP. The response to IFN seems to be related to the one obtained with previous treatments. Indeed 80% of the patients who were responsive to previous steroids, high dose immunoglobulins or azidothymidine (HIV-ITP) showed a complete or partial response while only 43% of the refractory patients showed a partial response; the positive response rate in previously untreated patients was 73%.

Adult↗
PubMed1993

Prevalence of specific thrombotic accidents in patients with thrombocytosis.

The prevalence of specific thrombotic accidents recognized in 260 patients with thrombocytosis are reported. Ninety one were affected by PV, 86 by ET, 20 by MF and 63 by ST. The highest incidence of thrombosis was in the PV group. About half of ET and MF patients experienced a thrombosis. In all the patients thrombosis preferentially affected the cerebrovascular district (17.3% of the cases). Coronary artery disease occurred in PV while peripheral vascular disease was frequent in ET. Portal vein district thrombosis is not rare during the course of all MPD (7.1%). Apparently, deep vein thrombosis occurs in all patients with both primary and secondary thrombocytosis.

Adult↗
PubMed1993

Mild haemophilia A fails to protect from coronary artery disease: the report of two cases.

The description of two additional cases of coronary artery disease in haemophiliacs is reported. Both patients are affected by mild haemophilia A. The first one was not aware of his coagulation disorder and therefore he had never been treated with FVIII concentrates, despite the occurrence of severe and recurrent articular and gastric bleeding episodes. He underwent cardiac catheterization that gave evidence of extensive coronary atherosclerosis. Percutaneous transluminal coronary angioplasty (PTCA) was then performed. The second patient had an inferior myocardial infarction. Influence of cardiovascular risk factors in haemophiliacs and the possible role of thrombosis in the pathogenesis of atherosclerosis are discussed.

Angioplasty, Balloon, Coronary↗
PubMed1993

Protein C, factor VII and prothrombin time as early markers of liver function recovery or failure after liver transplantation.

Irreversible initial non-function of the graft liver is a life-threatening early complication of orthotopic liver transplantation (OLT), which needs immediate retransplantation if the patient is to survive. Since protein C (PC) is a vitamin K dependent protein synthesized in the liver and with the same half-life as factor VII (FVII), the behaviour of PC in patients undergoing OLT was studied in comparison with prothrombin time (PT) and FVII. Twelve OLT patients were divided into two groups on the basis of clinical outcome: group A (six cases) in which OLT was successful, and group B (six cases) who developed initial non-function of the graft liver. PT, FVII activity (FVII:act) and antigen (FVII:Ag) and PC activity (PC:act) and antigen (PC:Ag) were carried out on six blood samples collected during the operation. At baseline, coagulation disorders were in agreement with the underlying liver disease, but no differences were seen between the two groups when all tests were considered. Ten minutes, 1, 2 and 3 h after liver reperfusion, mean PT and FVII:act were always significantly increased in good responder patients compared to non-responders. FVII:Ag and PC:Ag were significantly higher in group A than in group B starting 2 h after the liver graft reperfusion; no difference was seen in PC:act levels between the two groups. In addition, PC:Ag mean levels were increased with respect to corresponding PC:act values in non-responder patients, suggesting a qualitative rather than quantitative defect of protein synthesis due to liver damage. In conclusion, PT and FVII:act were more sensitive than PC activity as early prognostic indices of clinical outcome in OLT.

Adult↗
PubMed1993

The importance of serial immunoglobulin evaluations in HIV-seropositive haemophiliacs.

The aim of our investigation was to evaluate whether the alteration of immunoglobulins (Igs) may be a predictive marker of the evolution of HIV infection in seropositive haemophiliacs. For this purpose two groups of haemophiliac patients (16 seronegative and 21 seropositive) were compared to evaluate the variations of the Ig profile over a period of 5 years (1985-1989). The two populations were similar for the number of transfusions of blood products and for the severity of post-transfusional hepatic disorders. The IgM increase, in the first stages of HIV infection, appears to be more discriminant than polyclonal elevation of IgG, which is already present in seronegative polytransfused haemophiliac patients.

Biomarkers↗
PubMed1993

Bleeding as a cause of death in HIV-seropositive patients with congenital clotting disorders.

The causes of death in a group of HIV-seropositive patients suffering from congenital clotting disorders (cCD) were studied. During the past 6 years, we have followed 19 patients with cCD and HIV infection. Eight patients fulfilled revised CDC criteria for AIDS, 6 subjects reached stage III of CDC, and 5 remained asymptomatic (CDC stage II). All patients who developed AIDS died. In 5 patients, the terminal cause of death was a severe haemorrhage (hematemesis, melena or haemoptysis) after gastrointestinal or lung opportunistic infections. Two other patients died as a consequence of disseminated infections but without significant bleeding. Only one subject died due to neoplastic disease. In the first stages of CDC (II and III), no increase in bleeding symptoms were seen in cCD HIV infected patients. The risk of haemorrhages is, however, increased in AIDS patients. Adequate replacement therapy should be started early whenever severe opportunistic infections appear.

AIDS-Related Opportunistic Infections↗