The relationship between suture number and the healing process of end-to-end arterial anastomosis

In spite of the grate experience accumulated in vascular repairing, the ideal number of sutures for vascular anastomosis remains controversial. It is generally thought that the more stitches applied in a vascular anastomosis, the lesser resistant the anastomosis will be. The purpose of this study was to test this hypothesis in 20 rabbits, in which both carotid arteries were cross sectioned and repaired by end-to-end anastomosis with 8 interrupted sutures in one side (G1) and 16 in the other side (G2). After 3 and 15 days, the animals were randomly allocated for tensile strength, hydroxyproline determination (7 animals) and for histologic analysis of the anastomosis (3 animals). Conventional staining procedures (hematoxylin-eosin and Masson methods) and the picrosirius red polarization (PSP) technique for collagen type determination were used. From 3 to 15 days, the tensile strength increased in both groups, from 265.0±-44.4g to 391.2±-49.0g in G1 and from 310.0±-71.5g to 348.7±-84.0g in G2 (p<0.005), with no statistical difference between the groups in each period of study. The hydroxyproline content, expressed as hydroxyproline/protein ratio, varied from 0.04±-0.01 to 0.05±-0.02 in G1 and from 0.05±-0.01 to 0.05±-0.02 in G2, with no significant difference between periods and groups. The histology showed similar inflammatory and reparative aspects in both groups. In both groups and periods the PSP technique demonstrated predominantly type I collagen in relation to type III collagen in the anastomosis. We concluded that even doubling the number of stitches, the healing process and strength did not change in the arterial anastomosis

Liver response to low-hexachlorobenzene exposure in protein- or energy-restricted rats

The individual effects of protein deficiency and energy restriction on liver response to low-hexachlorobenzene (HCB) exposure were investigated in adult male Wistar rats. In rats fed either the low-protein or control diet, the only effect caused by HCB was a decrease in paralysis time following an ip injection of zoxazolamine. This decrease was similar for both groups. In the animals subjected to energy restriction, HCB induced a greater decrease in paralysis time, an increase in the size of centrilobular hepatocytes, a lower liver DNA content and an increased concentration of HCB in the adipose tissue, compared with the control and protein-deficient groups. Our data suggest that energy restriction increases liver response to HCB, while protein deficiency does not impair the hepatic reaction to small doses of HCB exposure