Beta-amyloidolysis and glutathione in Alzheimer's disease.

In this review, we hypothesized the importance of the interaction between the brain glutathione (GSH) system, the proteolytic tissue plasminogen activator (t-PA)/plasminogen/ plasmin system, regulated by plasminogen activator inhibitor (PAI-1), and neuroserpin in the pathogenesis of Alzheimer's disease. The histopathological characteristic hallmark that gives personality to the diagnosis of Alzheimer's disease is the accumulation of neurofibroid tangles located intracellularly in the brain, such as the protein tau and extracellular senile plaques made primarily of amyloidal substance. These formations of complex etiology are intimately related to GSH, brain protective antioxidants, and the proteolytic system, in which t-PA plays a key role. There is scientific evidence that suggests a relationship between aging, a number of neurodegenerative disorders, and the excessive production of reactive oxygen species and accompanying decreased brain proteolysis. The plasminogen system in the brain is an essential proteolytic mechanism that effectively degrades amyloid peptides ("beta-amyloidolysis") through action of the plasmin, and this physiologic process may be considered to be a means of prevention of neurodegenerative disorders. In parallel to the decrease in GSH levels seen in aging, there is also a decrease in plasmin brain activity and a progressive decrease of t-PA activity, caused by a decrease in the expression of the t-PA together with an increase of the PAI-1 levels, which rise to an increment in the production of amyloid peptides and a lesser clearance of them. Better knowledge of the GSH mechanism and cerebral proteolysis will allow us to hypothesize about therapeutic practices.

Use of sulodexide in patients with peripheral vascular disease.

Sulodexide is a highly purified glycosaminoglycan containing a combination of heparan sulfate with affinity for antithrombin III and dermatan sulfate with affinity for heparin cofactor II. This antithrombotic and antithrombin activity is of great pharmacologic interest and makes sulodexide a suitable drug for the prophylaxis and treatment of arterial and venous peripheral diseases. In arterial pathology, changes in the Winsor Index, improvement in peripheral blood flow, and reduction in pain-free walking distance confirm that treatment with oral sulodexide is effective. Lipid components linked to the genesis of peripheral vascular processes, including triglycerides, total cholesterol, and low-density lipoprotein fractions, as well as plasma and blood viscosity, are reduced by the administration of sulodexide, whereas the high-density lipoprotein fraction increases. Sulodexide inhibits aggregation and adhesion of platelets at the level of the vascular wall, reduces plasma fibrinogen concentrations, reduces plasminogen activator inhibitor-1, and increases tissue plasminogen activator, as well as systemic fibrinolytic and thrombolytic activity, thereby demonstrating efficacy in the treatment of thromboembolic disease. There is no interaction between sulodexide and other drugs used as long-term treatment for peripheral vascular disease. It is well tolerated, and the adverse reactions described after oral administration are related mainly to transient gastrointestinal intolerance, ie, nausea, dyspepsia, and minor bowel symptoms. Sulodexide may become the treatment of choice when dealing with vascular diseases and their complications, as well as for the prevention of venous thromboembolic disease, being particularly indicated in elderly patients, due to its good tolerability and ease of management.

[Do we use thromboprophylaxis rationally in minimally invasive laparoscopic surgery?]. / Utilizamos racionalmente la tromboprofilaxis en la cirugía mínimamente invasiva por laparoscopia?

The case of a patient who developed deep venous thrombosis of the lower extremities in the late postoperative course after laparoscopic cholecystectomy is presented. Thrombosis occurred in spite of correct prophylactic therapy. Factors influencing and predisposing to thromboembolism are reviewed, in particular the effect of pneumoperitoneum. Longer prophylaxis is probably required.

[Spontaneous retroperitoneal hemorrhage induced by anticoagulation treatment]. / Hemorragia retroperitoneal espontánea inducida por tratamiento anticoagulante.

Contribution of one case of spontaneous retroperitoneal haemorrhage presented after therapy with anticoagulants. Review of causes of transperitoneal haemorrhage, relative frequency, as well as signs and symptoms, and diagnosis. The sparse number of haemorrhagic complications after anticoagulant therapy with heparin and urokinase-associated adjusted heparin are described. Treatment is instituted based on precipitating condition and, in the present case, with suppression of medication and volume replacement together with an strict evolutive monitoring by means of ultrasound, computerized axial tomography (CT) and magnetic nuclear resonance (MNR).

[The fibrinolytic system and total parenteral nutrition]. / Sistema fibrinolítico y nutrición parenteral total.

A study is presented which was carried out in twenty-five patients operated on in a surgical service, and who received total parenteral nutrition. Samples were taken to check modifications to the fibrinolytic system occurring after administration of hyperosmotic solutions, principally lipidic emulsions, from a contemporary standpoint. We performed three extractions: on day one, day five and following the withdrawal of the fat emulsion, with study of modifications to antithrombin III, alpha 2 antiplasmin, plasminogen, C protein, plasminogen tissular activator (t-PA), plasminogen tissular activator inhibitor (PAI 1), fibrinogen, and fibrinogen/fibrin degradation products. The laboratory techniques used are shown, along with the results obtained: increased for alpha 2 antiplasmin and antigenic t-PA with significant values (p < 0.05) on the day of withdrawal in comparison with pre-PN values, plus increased values for plasminogen, fibrinogen/fibrin degradation products and t-PA activity. In conclusion, it is suggested that antithrombin III deficiency, along with reduction in C protein levels and increased fibrinogen and PAI 1 concentration predispose patients with t-PA release defects to thrombo-embolic complication.

[Importance of portal hypertension in the release of tissue plasminogen activator (t-PA): experimental study in the rat]. / Importancia de la hipertensión portal en la liberación de activador tisular del plasminógeno (t-PA): estudio experimental en la rata.

Tissue plasminogen activator (t-PA) activity was studied in three different experimental models of male Wistar rats; hepatic lesion without portal hypertension, portal hypertension without hepatic lesion and portal hypertension plus function liver suppression by ligation of both portal vein and hepatic artery. t-PA activity was higher in animals with portal hypertension alone than in animals with only hepatic lesion (146%). Maximal values were present in animals with functional liver suppression (1.774% vs. controls, 248% vs. hepatic lesion and 169% vs. portal hypertension only). These results suggest that both reduced hepatic t-PA clearance and portal hypertension could be involved in the increased t-PA activity normally appearing in chronic liver disease.