Effect of ischemic preconditioning on skeletal tissue tolerance after warm venous ischemia.

PURPOSE: Free muscular flaps are commonly used in plastic surgery. The main reason of failure is thrombosis induced by a phenomenon called ischemia reperfusion. Preconditioning showed an interest to prevent ischemia reperfusion injury in transplantation surgery. The aim of the study is to evaluate the effect of ischemic preconditioning on skeletal tissue tolerance after warm venous ischemia. MATERIALS AND METHODS: We realized an experimental study with latissimus dorsi flaps of 12 pigs, divided in 6 groups in function of their time of preconditioning and duration of warm venous ischemia. A morphologic analysis was performed measuring cell's diameter and interstitial tissue area and notifying the presence or absence of neutrophils, necrosis or intravascular thrombosis. To detect inflammation, necrosis or hypoxia, immunohistochemistry was effectuated using the follow primary antibodies, AIF, HIF1 alpha, caspase 3, SOD 1 and PKC epsilon. TUNEL assay showed apoptosis cells, were realized. One way Anova test was performed to compare the quantitative evolution over time of histological parameters and rate of apoptosis. RESULTS: Preconditioning of 40min or 1hour allowed to reduced ischemia reperfusion lesions: no cellular or interstitial oedema, reduction of neutrophils infiltrate and intravascular thrombus. TUNEL assay showed a higher rate of apoptosis nucleus for the control group E compared to preconditioning group C and D. Immunohistochemistry results were no relevant. CONCLUSION: We showed a diminution of lesions of ischemia reperfusion for experimental groups with preconditioning: diminution of interstitial oedema, of cellular oedema, diminution of neutrophils infiltrated and level of apoptosis cells. Preconditioning of 40minutes were as efficient as one hour.

Cloning and expression of activator of CREM in testis in human testicular tissue.

Activator of cAMP-responsive element modulator (CREM) in testis (ACT) has recently been found in the mouse testis where it activates CREM, a transcription factor essential for the differentiation of spermatids into mature spermatozoa. The importance of CREM in human spermatogenesis prompted us to examine whether ACT was also present in the human testis. Western blot analysis, performed with an anti-mouse ACT serum, showed the presence of a single immunoreactive band of a size similar to murine ACT. A library screening resulted in the isolation and characterization of the complete cDNA which showed 88% homology with the mouse counterpart. The human ACT gene is composed of five coding exons, being the first untranslated, and the mRNA spans 835 nucleotides coding for a 284 amino acid protein. Expression studies by RT-PCR confirmed that ACT is present in normal human testis. The human ACT gene is localized on the chromosome 6.

Bovine seminal RNase induces apoptosis in normal proliferating lymphocytes.

Bovine seminal ribonuclease is a member of the RISBAses (ribonucleases with special biological actions) family. It exerts specific anti-tumor, embryotoxic, aspermatogenic and immunosuppressive activities. The cytotoxic effect of bovine seminal ribonuclease on tumor cells is accompanied by the induction of apoptosis. We provide ultrastructural and flow cytometry evidence of apoptotic death following bovine seminal ribonuclease treatment, in normal cells and phytohemagglutinin-stimulated lymphocytes. Transmission and scanning electron microscopy, which were fully supported by flow cytometry data, showed typical features of apoptosis, such as decreased cell size, chromatin condensation, fragmentation in micronuclei, and the presence of apoptotic bodies.