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1.  Emergency reversal of anticoagulation: from theory to real use of prothrombin complex concentrates. A retrospective Italian experience 
Blood Transfusion  2012;10(1):87-94.
Prothrombin Complex Concentrates (PCC) are administered to normalise blood coagulation in patients receiving oral anticoagulant therapy (OAT). Rapid reversal of OAT is essential in case of major bleeding, internal haemorrhage or surgery.
The primary end-point was to evaluate whether PCC in our hospital were being used in compliance with international and national guidelines for the reversal of OAT on an emergency basis. The secondary end-point was to evaluate the efficacy and safety of PCC.
Materials and methods
All patients receiving OAT who required rapid reversal anticoagulation because they had to undergo emergency surgery or urgent invasive techniques following an overdose of oral anticoagulants were eligible for this retrospective observational study.
Forty-seven patients receiving OAT who needed rapid reverse of anticoagulation were enrolled in our study. The patients were divided in two groups: (i) group A (n=23), patients needed haemostatic treatment before neurosurgery after a head injury and (ii) group B (n=24), patients with critical haemorrhage because of an overdose of oral anticoagulants. The International Normalised Ratio (INR) was checked before and after infusion of the PCC. The mean INR in group A was 2.7 before and 1.43 after infusion of the PCC; in group B the mean INR of 6.58, before and 1.92 after drug infusion. The use of vitamin K, fresh-frozen plasma and red blood cells was also considered. During our study 22 patients died, but no adverse effects following PCC administration were recorded.
In our study three-factor-PCC was found to be effective and safe in rapidly reversing the effects of OAT, although it was not always administered in accordance with international or national guidelines. The dose, time of administration and monitoring often differed from those recommended. In the light of these findings, we advocate the use of single standard protocol to guide the correct use of PCC in each hospital ward.
PMCID: PMC3258994  PMID: 22044952
prothrombin complex concentrate; oral anticoagulant therapy; reversal of anticoagulation guidelines
2.  Fibroblast Growth Factor-2 and the HIV-1 Tat Protein Synergize in Promoting Bcl-2 Expression and Preventing Endothelial Cell Apoptosis: Implications for the Pathogenesis of AIDS-Associated Kaposi's Sarcoma 
Kaposi's sarcoma (KS) is a vascular tumor frequently occurring in Human Immunodeficiency Virus- (HIV-) 1-infected individuals. Our previous work indicated that the angiogenic fibroblast growth factor (FGF)-2 and the Tat protein of HIV-1, both expressed in KS lesions of HIV-infected patients, synergize at inducing angioproliferative, KS-like lesions in mice. Here we show that the development of angioproliferative lesions promoted in mice by combined Tat and FGF-2 associates with an increase in the levels of expression of the antiapoptotic Bcl-2 protein. Upregulation of Bcl-2 expression by combined FGF-2 and Tat occurs also in vitro, and this protects human primary endothelial cells from programmed cell death. As Bcl-2 is expressed in human KS lesions in a fashion paralleling the progression of the disease, these findings suggest a molecular mechanism by which Tat and FGF-2 cooperate in KS maintenance and progression in HIV-infected individuals.
PMCID: PMC3189568  PMID: 22007303
3.  Emergency reversal of anticoagulation with a three-factor prothrombin complex concentrate in patients with intracranial haemorrhage 
Blood Transfusion  2011;9(2):148-155.
Intracranial haemorrhage is a serious and potentially fatal complication of oral anticoagulant therapy. Prothrombin complex concentrates can substantially shorten the time needed to reverse the effects of oral anticoagulants. The aim of this study was to determine the efficacy and safety of a prothrombin complex concentrate for rapid reversal of oral anticoagulant therapy in patients with intracranial haemorrhage.
Patients receiving oral anticoagulant therapy and suffering from acute intracranial haemorrhage were eligible for this prospective cohort study if their International Normalised Ratio (INR) was higher than or equal to 2.0. The prothrombin complex concentrate was infused at doses of 35–50 IU/kg, stratified according to the initial INR.
Forty-six patients (25 males; mean age: 75 years; range 38–92 years) were enrolled. The median INR at presentation was 3.5 (range, 2–9). At 30 minutes after administration of the prothrombin complex concentrate, the median INR was 1.3 (range, 0.9–3), and the INR then declined to less than or equal to 1.5 in 75% of patients. The benefit of the prothrombin complex concentrate was maintained for a long time, since the median INR remained lower than or equal to 1.5 (median, 1.16; range, 0.9–2.2) at 96% of all post-infusion time-points up to 96 hours. No thrombotic complications or significant adverse events were observed during hospitalisation; six patients (13%) died, but none of these deaths was judged to be related to administration of the prothrombin complex concentrate.
Prothrombin complex concentrates are an effective, rapid and safe treatment for the urgent reversal of oral anticoagulation in patients with intracranial haemorrhage. Broader use of prothrombin complex concentrates in this clinical setting appears to be appropriate.
PMCID: PMC3096857  PMID: 21251465
intracranial haemorrhage; oral anticoagulants; prothrombin complex concentrates
4.  HIV-1 Tat Regulates Endothelial Cell Cycle Progression via Activation of the Ras/ERK MAPK Signaling PathwayD⃞ 
Molecular Biology of the Cell  2006;17(4):1985-1994.
Tat, the transactivator of HIV-1 gene expression, is released by acutely HIV-1-infected T-cells and promotes adhesion, migration, and growth of inflammatory cytokine-activated endothelial and Kaposi's sarcoma cells. It has been previously demonstrated that these effects of Tat are due to its ability to bind through its arginine-glycine-aspartic (RGD) region to the α5β1 and αvβ3 integrins. However, the signaling pathways linking Tat to the regulation of cellular functions are incompletely understood. Here, we report that Tat ligation on human endothelial cells results in the activation of the small GTPases Ras and Rac and the mitogen-activated protein kinase ERK, specifically through its RGD region. In addition, we demonstrated that Tat activation of Ras, but not of Rac, induces ERK phosphorylation. We also found that the receptor proximal events accompanying Tat-induced Ras activation are mediated by tyrosine phosphorylation of Shc and recruitment of Grb2. Moreover, Tat enabled endothelial cells to progress through the G1 phase in response to bFGF, and the process is linked to ERK activation. Taken together, these data provide novel evidence about the ability of Tat to activate the Ras-ERK cascade which may be relevant for endothelial cell proliferation and for Kaposi's sarcoma progression.
PMCID: PMC1415297  PMID: 16436505
5.  Angiogenic Effects of Extracellular Human Immunodeficiency Virus Type 1 Tat Protein and Its Role in the Pathogenesis of AIDS-Associated Kaposi's Sarcoma 
Clinical Microbiology Reviews  2002;15(2):310-326.
The Tat protein of human immunodeficiency virus (HIV) type 1 is a transactivator of viral gene expression that is required for virus replication and spread. Moreover, Tat is released by acutely HIV-infected cells via a leaderless secretory pathway and in a biologically active form that exerts effects on both HIV-infected and uninfected cells from different organs and systems. This review focuses on the activities of extracellular Tat protein on endothelial cells, on angiogenesis, and on the pathogenesis of AIDS-associated angioproliferative diseases such as Kaposi's sarcoma. In particular, we discuss results from different groups indicating that Tat mimics the proangiogenic activities of extracellular matrix molecules and that it enhances the effects of angiogenic factors.
PMCID: PMC118071  PMID: 11932235
6.  Immunoreactivity to Putative B-Cell Epitopes of Hepatitis G Virus Polyprotein in Viremic and Nonviremic Subjects 
The hepatitis G virus (HGV) polyprotein was scanned by computer-aided prediction of antigenicity to search for B-cell epitopes. Four polypeptide sequences, V37D (amino acids [aa] 1685 to 1721), V36S (aa 2102 to 2137), P37R (aa 2156 to 2192), and C40P (aa 2280 to 2319), were identified and synthesized for use in immunoassays. Antibodies to these peptides were searched for in a panel of 239 serum samples, which were also tested for anti-E2 antibodies and HGV RNA. Furthermore, the course of HGV markers was studied prospectively in four patients who had been transfused with HGV RNA-positive blood. There was a negative association between immunoreactivity to V37D and P37R and presence of HGV RNA (2 of 53 and 1 of 53, respectively; P < 0.05); none of the subjects with dual antibody positivity was HGV RNA positive. Anti-V37D and anti-P37R antibodies compared favorably with anti-E2 antibodies as markers of recovery from HGV infection. These results might be useful for the development of new, more sensitive diagnostic assays.
PMCID: PMC95730  PMID: 10391865
7.  Activation of Matrix-Metalloproteinase-2 and Membrane-Type-1-Matrix-Metalloproteinase in Endothelial Cells and Induction of Vascular Permeability In Vivo by Human Immunodeficiency Virus-1 Tat Protein and Basic Fibroblast Growth Factor 
Molecular Biology of the Cell  2001;12(10):2934-2946.
Previous studies indicated that the Tat protein of human immunodeficiency virus type-1 (HIV-1) is a progression factor for Kaposi's sarcoma (KS). Specifically, extracellular Tat cooperates with basic fibroblast growth factor (bFGF) in promoting KS and endothelial cell growth and locomotion and in inducing KS-like lesions in vivo. Here we show that Tat and bFGF combined increase matrix-metalloproteinase-2 (MMP-2) secretion and activation in endothelial cells in an additive/synergistic manner. These effects are due to the activation of the membrane-type-1-matrix-metalloproteinase and to the induction of the membrane-bound tissue inhibitor of metalloproteinase-2 (TIMP-2) by Tat and bFGF combined, but also to Tat-mediated inhibition of both basal or bFGF-induced TIMP-1 and -2 secretion. Consistent with this, Tat and bFGF promote vascular permeability and edema in vivo that are blocked by a synthetic MMP inhibitor. Finally, high MMP-2 expression is detected in acquired immunodeficiency virus syndrome (AIDS)-KS lesions, and increased levels of MMP-2 are found in plasma from patients with AIDS-KS compared with HIV-uninfected individuals with classic KS, indicating that these mechanisms are operative in AIDS-KS. This suggests a novel pathway by which Tat can increase KS aggressiveness or induce vasculopathy in the setting of HIV-1 infection.
PMCID: PMC60146  PMID: 11598182

Results 1-7 (7)