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M Colucci

Publications and source records attributed to M Colucci.

101 records · Page 6Linked to original sources
PubMedDate not supplied

Reduced fibrinolytic activity in glomeruli isolated from rabbits infused with tumor necrosis factor.

Glomerular fibrin deposition may result from local activation of blood coagulation and/or impaired removal by the fibrinolytic system. We evaluated the fibrinolytic activity of glomeruli isolated from rabbits infused for 5 h with tumor necrosis factor (TNF) at the doses of 0.8 micrograms/kg/h (n = 5) and 8 micrograms/kg/h (n = 3) or with endotoxin (8 micrograms/kg/h, n = 7). Animals infused with vehicle (n = 11) served as control group. Plasminogen activator (PA) activity of glomerular extracts from rabbits infused with 8 micrograms/kg/h of TNF or endotoxin was significantly lower than that of samples from control animals (p = 0.013 and p = 0.003, respectively). At the dose of 0.8 micrograms/kg/h, TNF caused a reduction in glomerular PA activity which, however, did not reach statistical significance. Neither plasminogen-independent activity nor PA inhibitor activity was detected in glomerular extracts. Fibrin autography of control extracts revealed the presence of two main fibrinolytic activities comigrating with purified urokinase-type and tissue-type PAs. In treated samples, the bands corresponding to free PAs were markedly reduced, with no evidence of enzyme-inhibitor complex formation. Local reduction of fibrinolytic capacity may contribute to intraglomerular fibrin deposition during endotoxemia or in renal inflammatory diseases associated with TNF production.

Animals↗
PubMedDate not supplied

Hemostatic variables in homozygous familial hypercholesterolemia. Effect of regular plasma cholesterol removal by low density lipoprotein apheresis.

Plasma levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) and the in vitro ability of platelets to aggregate and of monocytes to express procoagulant (tissue factor) activity (PCA) were evaluated in five patients who are homozygous for familial hypercholesterolemia (FH) before and after a single and a regular 5-month cholesterol removal by low density lipoprotein (LDL) apheresis. The biweekly procedure resulted in a 25% to 30% reduction (approximately 150 mg/dl) in total and LDL cholesterol (both were greater than 550 mg/dl at the beginning of the study). The basal levels of t-PA antigen and fibrinolytic activity before and after 10 minutes of venous stasis, basal PAI activity, and PAI-1 antigen were comparable to controls and were not affected by LDL apheresis. Likewise, regardless of the cholesterol removal, the PCA of freshly isolated monocytes and that of monocytes incubated with lipopolysaccharide did not differ from control values. Finally, the pre-apheresis sensitivity of platelets to adenosine diphosphate, arachidonic acid, and collagen was 1.5 to 2 times the normal value. This ratio was unchanged throughout the 5-month procedure. We conclude that fibrinolysis and monocyte PCA are normal in FH patients, whereas platelet aggregation is abnormally high, and none of these parameters is significantly affected by a 25% to 30% reduction in total and LDL cholesterol by LDL apheresis. Furthermore, our data suggest that removal of cholesterol from plasma by LDL apheresis is important for gaining insight into the mechanisms involved in the ischemic complications of arteriosclerosis in FH patients.

Adolescent↗
PubMedDate not supplied

A role for platelets and thrombin in the juvenile stroke of two siblings with defective thrombin-adsorbing capacity of fibrin(ogen).

Binding of iodine-125-labeled thrombin to fibrin clots from two siblings with juvenile stroke was 30% of normal, and abnormally high amounts of the radioligand (not adsorbed by fibrin) were found in the supernatant. In concordance with this finding, supernatants from the patients' fibrin clots caused abnormal enhancement of platelet aggregation, ATP secretion, and binding of 125I-fibrinogen to platelets exposed to subthreshold concentrations of ADP or epinephrine. Hirudin suppressed the enhancing effect of the patients' supernatants, and substitution of gamma-thrombin for alpha-thrombin led to normalization of platelet responses. Under some experimental conditions, degradation of the patients' fibrinogen by plasmin was impaired. However, the euglobulin lysis time, the rate of fibrin degradation by plasmin, and the lysis of the patients' plasma clots by human melanoma tissue-type plasminogen activator were normal. Patients' plasmas, as well as purified fibrinogen, showed a prolonged thrombin time (partially corrected by 10 mM CaCl2) and an impaired release of fibrinopeptide A in response to thrombin. However, the release in response to reptilase was normal, and the reptilase, ancrod, and thrombin coagulase times were within control (normal) values. In addition, the patients' fibrinogen showed normal polymerization of preformed fibrin monomers, normal sialic acid content, and normal binding to ADP or epinephrine-stimulated platelets. Our studies support the concept that thrombin and platelets play an important role in the occurrence of stroke in these patients and suggest a direction to be followed to identify the mechanism(s) contributing to thrombosis in subjects with abnormal fibrinopeptide release.

Adenosine Diphosphate↗
PubMedDate not supplied

Reduction of the plasma levels of tissue plasminogen activator after infusion of a lipid emulsion in humans.

A lipid emulsion of soybean oil, egg lecithin, and glycerol, widely used as a standard component of parenteral nutrition regimens, has been reported to induce changes in some hemostatic parameters known to be associated with increased thrombotic risk. We studied the effect of a single infusion of this lipid emulsion (500 mL of a 10% emulsion, give over 5 to 6 hours) on the plasma levels of tissue plasminogen activator and plasminogen activator inhibitor 1 antigens in 12 patients with various diseases. Twelve matched patients, not treated with lipid, served as controls. In patients receiving the lipid emulsion, tissue plasminogen activator was markedly reduced at the end of the infusion (p < .001) and remained significantly lower than the basal levels 24 hours later (p < .05). By contrast, in control patients, the activator was slightly but significantly increased (p < .01) at the time interval corresponding to the postinfusion sample. Plasminogen activator inhibitor 1 was similar in control and treated patients at all intervals. The release of tissue plasminogen activator in response to 10 minutes of venous stasis, evaluated in six lipid-treated patients at the end of the infusion, was not different from that observed in six control patients. It is concluded that the lipid emulsion induces a marked decrease in the circulating levels of tissue plasminogen activator.

Adult↗
PubMedDate not supplied

[Expression of tissue factor and vascular endothelial growth factor in colorectal carcinoma].

Tissue factor (TF) and vascular endothelial growth factor (VEGF) play an important role in tumor progression and metastasis. We analyzed their expression in the carcinoma and normal mucosa of 53 colorectal cancer patients. VEGF levels were significantly higher in the tumor and correlated with TF expression. No correlation was found with tumor stage. TF may influence tumor growth and metastasis by modulating VEGF expression and neoangiogenesis.

Adenocarcinoma↗