Effects of heparan-sulphate administration on clotting parameters and serum thromboxane B2 levels in cholesterol fed rabbits.

We evaluated the effects of heparan-sulphate administration on clotting times, thromboelastographic parameters and serum thromboxane B2 levels in hypercholesterolemic rabbits with aortic atherosclerotic lesions (sudanophilic areas). 24 New Zealand male rabbits were divided into three groups of 8 animals each. Group A and B were fed a rabbit chow diet containing 0.7% of cholesterol whereas Group C was fed a standard rabbit diet without cholesterol. Group A was treated by subcutaneous route with 6 mg/kg/day of heparan sulphate. At the beginning of the study and after 3 and 6 months of treatment, serum cholesterol and thromboxane B2 levels were tested. Furthermore, at the end of the experiment, we evaluated plasma fibrinogen, aPTT, PT and TT values. The administration of heparan-sulphate in cholesterol fed rabbits produced: a reduction of plasma fibrinogen levels, without modifying aPTT and TT; a protective effect vs the lengthening in PT values, likely induced by cholesterol rich diet; a reduction of plasma thrombophilic activities and of aortic atheromasic involvement induced by dietetic cholesterol intake. However, increased serum thromboxane B2 levels, likely through a proaggregant activity were observed. We suggest that heparan-sulphate administration, in cholesterol fed rabbits, has a favourable effect on clotting parameters, while contrasting effects were found on platelet activity.

Progression of induced aortic atherosclerosis in rabbits fed a high cholesterol diet.

In this study we have evaluated the progression of atheromatosis in aortic arch, thoracic aorta and abdominal aorta in rabbits fed a high cholesterol diet. The aortic atheromatosis decreased progressively from the aortic arch to the abdominal aorta after 6 months of high cholesterol diet. It is possible that a different segmental resistance to hypercholesterolemic damage may be involved in the cranio caudal progression of atheromatosis in rabbits.

Relationship between serum cholesterol and thromboxane B2 levels and atherosclerotic lesions in rabbits fed a high cholesterol diet.

The aim of our study was to evaluate the effects of diet induced hypercholesterolemia and associated atherosclerosis in rabbits on serum thromboxane B2 levels. We have determined thromboxane B2 in serum of hypercholesterolemic rabbits with atherosclerosis and in normocholesterolemic rabbits without atherosclerosis. Our data show only a mildly higher serum thromboxane levels in hypercholesterolemic rabbits and extensive atherosclerosis than in controls without atherosclerosis. In conclusion, these results show that diet induced hypercholesterolemia was not associated with thromboxane B2 generation, in spite of a diffuse experimental atheromatosis.

Alterations of calcium metabolism in spontaneously hypertensive rats.

We have examined the femurs of eight male spontaneously hypertensive rats and eight male Wistar Kyoto rats, aged 24 weeks. The mineral density of the bones was determined at the mid-point of the femurs by dual photon absorptiometry and the calcium content was estimated on bone ash by atomic absorption spectrophotometry. The data show that spontaneously hypertensive rats have lower bone density and calcium content than do age-matched Wistar Kyoto rats.

Amikacin-induced liver toxicity: correlations between biochemical indexes and ultrastructural features in an experimental model.

In previous studies, aminoglycosides (AG) as gentamicin (G), dibekacin (D), tobramycin (T), netilmicin (N) and Sysomicin (S) were proved to induce ultrastructural alterations in the liver of experimental animals. The aim of this studies is to investigate the effect of amikacin (AK) on rabbit liver which is commonly used in infections resistant to other AG; this was done studying both the common blood parameters and ultrastructural changes. The study was accomplished in 24 New-Zealand rabbits, twelve received 20 mg/kg AK every 12 hours for 2 weeks. Thereafter the animals were anesthesized and liver slices were obtained for transmission electron microscopy. As results obvious signs of primary and secondary microcholestasis associated to mitochondrial cristae detachment and phospholipid aggregations were noted; this last finding was less marked when compared to previous studies employing other AG. In the AK treated group, blood tests showed a significant increased in only Blood Urea Nitrogen (BUN) and an insignificant rise in AST levels. Our findings are consistent with an AK induced liver toxicity albeit less evident with respect to the other AG.

[Ultrastructural study of the liver in rabbits treated with diclofenac]. / Studio ultrastrutturale epatico in conigli trattati con diclofenac.

The existence of alterations of common indexes of hepatic function, and the case-reports of acute hepatitis after the use of diclofenac sodium are the rationale for this experimental study, in which 8 rabbits were given 15 mg/kg day of diclofenac, to check ultrastructural modifications with respect to a control group. The analysis showed the typical signs of primary and secondary microcholestasis, indicating the existence of liver distress. This finding, from a clinical standpoint, suggests caution in the administration of this drug, chiefly in the hepatopathic patients.