RESUMEN

Polyvinyl alcohol/chitosan (PVA/Ch) hydrogels containing 1 and 3wt% of lignin nanoparticles (LNPs) were prepared through a freezing-thaw procedure. Results from microstructural, thermal and mechanical characterization of LNPs based PVA/Ch demonstrated that the lowest amount of LNPs (1wt%) was beneficial, whereas the presence of agglomerates at higher LNP content limited the effect. Moreover, a different swelling behaviour was observed for hydrogels containing LNPs with respect of PVA/Ch, due to the formation of a porous honeycomb-like structure. A synergic effect of Ch and LNPs was revealed in terms of antioxidative response by DPPH (1,1-Diphenyl-2-picryl-hydrazyl) activity of migrated substances, whereas results from antimicrobial tests confirmed LNPs as effective against Gram negative bacteria (E. coli) when compared to Gram positive (S.aureus and S. epidermidis) strains. The obtained results suggested the possible use of produced PVA/Ch hydrogels incorporating LNPs in many different sectors, such as drug delivery, food packaging, wound dressing.

Asunto(s)

RESUMEN

The study investigates whether combination therapy of sildenafil with imatinib at a low dose (20 mg/kg) further ameliorates pulmonary hypertension (PH) in rats. The effects on right ventricle pressure (RVP), and right ventricle hypertrophy (RVH) were assessed in experimental monocrotaline (MCT)-induced pulmonary hypertension. Combined therapy reversed the MCT-induced increase in RVP more than each drug alone and decreased RV hypertrophy (RV/LV+ S ratio), significantly. Such additive effects toward improvement of PH may result from both pharmacodynamic and pharmacokinetic drug-drug interactions, however, further studies are required to assess its mechanistic background.

Asunto(s)

RESUMEN

The object of this study was to investigate the influence of midazolam on the plasma concentrations and pharmacokinetic parameters of lidocaine in rabbits. Lidocaine levels were determined by the immunofluorescence polarization method, using Abbott reagents. After intravenous administration of a combined dose of midazolam (0.2 mg kg(-1)i.v.) with lidocaine (1 mg kg(-1)i.v.) a statistically perceivable decrease of lidocaine concentration, together with an increase of the constant rate of its elimination and reduction of the biological half-life with average time of lidocaine remaining in the system were observed. Midazolam administered intravenously together with lidocaine shortens the residence time of the drug.

Asunto(s)

RESUMEN

Some of anesthetic drugs cause cardiac arrhythmia, myocardial depression, blood pressure as well as hepatic and renal blood flow decrease. The aim of the following research study was the evaluation of midazolam effect on hemodynamic parameters in propranolol-treated rabbits. The following parameters: cardiac output and stroke volume, peripheral blood resistance, heart rate and blood pressure were estimated in the hemodynamics study. Blood pressure was significantly higher in case of propranolol and midazolam therapy as compared with midazolam alone. Blood pressure inconstancy did not exceed 20% of the initial value. Midazolam did not improve the depressive effect of propranolol on heart rate. The peripheral vascular resistance in coherent propranolol and midazolam therapy oscillated at the values observed after sole midazolam administration. After midazolam administration with propranolol, insignificant increase of cardiac output and stroke volume during the first minutes of experimental protocol correlated with marked decrease of peripheral blood resistance at the same time.

Asunto(s)

RESUMEN

Cardiac arrhythmia can be a serious complication during general anaesthesia of patients suffering from cardiac arrhythmias and using antiarrhythmic drugs. The aim of the present experiments was to establish the way in which lidocaine and verapamil influence haemodynamic parameters of rabbits after midazolam anaesthesia. The experiments were performed on rabbits. Heart rate was counted according to ECG. Blood pressure was measured directly in the carotid artery. Cardiac output, stroke volume, and total peripheral resistance were estimated using the method of human 125J albumin dilution. Midazolam caused a gradual fall of arterial blood pressure till 30 min of the experiment. The decrease of blood pressure in the first 45 min of the experiment might be a result of decreasing peripheral resistance, and after 60 min should be rather attributed to a decrease of cardiac output and stroke volume. Lidocaine did not change the influence of midazolam on the blood pressure and heart rate. The consequence was a decrease of blood pressure after midazolam and lidocaine administration. Combined administration of midazolam and lidocaine decreased the influence of both midazolam and lidocaine on the total peripheral resistance. An injection of midazolam with verapamil resulted in a significant decrease of blood pressure. Combined administration of midazolam and verapamil caused a significant decrease of heart rate as compared with the initial value and administration of midazolam alone.

Asunto(s)

RESUMEN

The course of Bietti's crystalline retinopathy, which has an autosomal-recessive mode of inheritance, is described with reference to three families. Initially, crystals appear in the inner and middle layers of the retina; in the third decade of life atrophy of the retinal pigment epithelium and of the choroid sets in. Secondary degeneration of the center of the retina results in the disappearance of the crystals in the degenerated areas.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

Studies were conducted to determine the role of bacteria and algae in the degradation of urea in industrial waste waters. The microflora accompanying algae in continuous cultures on waste waters from the nitrogen fertilizers industry was found to include bacteria capable of intensive degradation of urea. Urea hydrolyzing bacteria are with time eliminated from the algal culture. This elimination can be attributed to algal metabolites which inhibit the development of sensitive bacteria. The Chlorella vulgaris strain used in the treatment of wast waters from the nitrogen fertilizers industry did not hydrolyse urea.

Asunto(s)