Effects of melatonin and lactulose on the liver and kidneys in rats with obstructive jaundice

The negative effects of obstructive jaundice (OJ) on the liver and kidneys cause high morbidity and mortality. In this study, the effects of melatonin (M) and lactulose (L) on the liver and kidneys were investigated by inducing OJ in 30 rats in five groups (n = 6): controls, sham, M, L, and M + L. In the treatment group, after the rats' biliary canals were tied and cut, 10 mg/kg M IM and 2 ml/day L p.o. was administered for 7 days. The histopathologic findings in the liver and kidneys, tissue malonyl dialdehyde (MDA) levels, and serum biochemistry were evaluated. In the M group, pathological histologic findings were less marked than in the other groups; investigation of kidney cross-sections revealed no significant differences among groups. In the jaundiced rats liver MDA levels were significantly higher compared to the control group ( P < 0.001), but no such difference was observed in kidney MDA levels ( P > 0.05). L did not cause any significant changes in tissue MDA levels. There were no differences among groups with regard to serum levels of liver enzymes and bilirubin. Serum urea was significantly less in the group that received L ( P < 0.001), but the groups showed no significant differences with respect to creatinine values ( P > 0.05). The increase in serum total cholesterol was significantly less in the M + L group than in the other groups ( P < 0.001). We conclude that in the rats in which obstructive jaundice was induced, M administration reduced liver and kidney injury, but L and M + L did not lead to significant improvement.     

Mechanical and microarchitectural analyses of cancellous bone through experiment and computer simulation

The relationship between microarchitecture to the failure mechanism and mechanical properties can be assessed through experimental and computational methods. In this study, both methods were utilised using bovine cadavers. Twenty four samples of cancellous bone were extracted from fresh bovine and the samples were cleaned from excessive marrow. Uniaxial compression testing was performed with displacement control. After mechanical testing, each specimen was ashed in a furnace. Four of the samples were exemplarily scanned using micro-computed tomography (μCT) and three dimensional models of the cancellous bones were reconstructed for finite element simulation. The mechanical properties and the failure modes obtained from numerical simulations were then compared to the experiments. Correlations between microarchitectural parameters to the mechanical properties and failure modes were then made. The Young’s modulus correlates well with the bone volume fraction with R ² = 0.615 and P value 0.013. Three different types of failure modes of cancellous bone were observed: oblique fracture (21.7%), perpendicular global fracture (47.8%), and scattered localised fracture (30.4%). However, no correlations were found between the failure modes to the morphological parameters. The percentage of error between computer predictions and the actual experimental test was from 6 to 12%. These mechanical properties and information on failure modes can be used for the development of synthetic cancellous bone.