No abstract

A short period of ischemia and reperfusion, called ischemic preconditioning, protects various tissues against subsequent sustained ischemic insults. We previously showed that apoptosis of hepatocytes and sinusoidal endothelial cells is a critical mechanism of injury in the ischemic liver. Because caspases, calpains, and Bcl-2 have a pivotal role in the regulation of apoptosis, we hypothesized that ischemic preconditioning protects by inhibition of apoptosis through down-regulation of caspase and calpain activities and upregulation of Bcl-2. A preconditioning period of 10 minutes of ischemia followed by 15 minutes of reperfusion maximally protected livers subjected to prolonged ischemia. After reperfusion, serum aspartate transaminase (AST) levels were reduced up to 3-fold in preconditioned animals. All animals subjected to 75 minutes of ischemia died, whereas all those who received ischemic preconditioning survived. Apoptosis of hepatocytes and sinusoidal endothelial cells, assessed by in situ TUNEL assay and DNA fragmentation by gel electrophoresis, was dramatically reduced with preconditioning. Caspase activity, measured by poly (adenosine diphosphate ribose) polymerase (PARP) proteolysis and a specific caspase-3 fluorometric assay, was inhibited by ischemic preconditioning. The antiapoptotic mechanism did not involve calpain-like activity or Bcl-2 expression because levels were similar in control and preconditioned livers. In conclusion, ischemic preconditioning confers dramatic protection against prolonged ischemia via inhibition of apoptosis through down-regulation of caspase 3 activity, independent of calpain-like activity or

Genitourinary Tuberculosis (GUTB) is the second most common extra-pulmonary manifestation of tuberculosis (Tb) and an isolated involvement of genital organs is reported in 5–30% of the cases. Genital involvement results from primary reactivation of latent bacilli either in the epididymis or the prostate or by secondary spread from the already infected urinary organs. The epididymis are the commonest involved organs affected primarily by a hematogenous mode of spread. Tb is characterized by extensive destruction and fibrosis, thus an early diagnosis may prevent function and organ loss. The gold standard for diagnosis is the isolation and culture of mycobacterium tuberculosis bacilli and in the cases of suspected GUTB, it is commonly looked for in the urinary samples. All body fluid specimens from possible sites of infection and aspirates from nodules must also be subjected to examination. Radiologic investigations including ultrasonography and contrast imaging may provide supportive evidence. Anti-tubercular chemotherapy is the first line of management for all forms of genital Tb and a 6 months course is the standard of care. Most patients with tubercular epididymo-orchitis respond to antitubercular therapy but may require open or percutaneous drainage. Infertility resulting from the tubercular affliction of the genitalia is multifactorial in origin and may persist even after successful chemotherapy. Multiple organ involvement with obstruction at several sites is characteristic and most of these cases are not amenable to surgical reconstruction. Thus, assisted reproduction is usually required. Post treatment, regular annual follow up is recommended even though, with the current multi drug therapy, the chances of relapse are low.

Hepatic damage following ischemia-reperfusion injury involves polymorphonuclear leukocytes (PMN) and platelet sequestration, however the mechanisms of adhesion remain elusive. In this study, using gene-targeted deficient mice, we evaluated P-selectin and its contribution to PMN and platelet adhesion in hepatic damage. In an in vivo warm ischemia model, hepatic injury was assessed by serum transaminase levels, survival, PMN adhesion by histological analysis, and platelet sequestration by immunostaining. Serum transaminase levels were strikingly reduced (by up to threefold) in the P-selectin deficient mice, particularly at 90 minutes of ischemia, when compared with wild-type controls. PMN adhesion and platelet sequestration was also significantly decreased in P-selectin deficient mice following 90 minutes of partial ischemia. Animal survival was significantly improved after 75 minutes of total hepatic ischemia in P-selectin deficient mice when compared with wild-type mice. Survival was also achieved after 90 minutes of ischemia in the mutant mice whereas none of the wild-type animals survived. These data show that P-selectin plays a critical role in PMN and platelet adhesion following ischemia-reperfusion injury to the liver. (HEPATOLOGY 1999; 29:1494-1502.)The pathogenesis of cell damage following reperfusion of ischemic tissue is an incompletely understood series of events. 1,2 Various mechanisms have been proposed including enhanced production of inflammatory mediators, 3-5 recruitment of polymorphonuclear leukocytes (PMN), 6,7 and blockage of blood flow. 7-9 The leukocyte-endothelial interaction that occurs following ischemia/reperfusion (I/Rp) injury has been shown to be important for microvascular dysfunction and release of cytotoxic mediators such as reactive oxygen intermediates and a variety of proteases. 10-12 We 13 and others 5,6,9,14,15 have shown leukocyte accumulation to be a critical determinant of hepatic I/Rp injury. Other blood elements including platelets adhere to the hepatic sinusoids in conditions of ischemia, 16,17 but little is known about their contribution to the injury.The adhesion of PMN and platelets to the vascular endothelium involves a variety of adhesion receptors. [18][19][20][21] The selectin family (P-, E-, and L-selectin) are the first to be engaged in the process, 19 with P-selectin acting at the earliest stage of interaction between PMN and the endothelium. P-selectin is found in the ␣ granules of resting platelets and Weibel-Palade bodies of endothelial cells, 18 and expression of P-selectin on the cell surface can occur within minutes under stimulation by mediators of inflammation such as thrombin, histamine, complement, and peroxide. 22 P-selectin is able to tether leukocytes to the endothelial surface through its ligand P-selectin glycoprotein ligand-1 (PSGL-1), which leads to their activation. 23 Once leukocytes attach, they can interact with flowing PMN and platelets through the action of P-and L-selectin, 23 which may lead to further adhesion of PMN and platelets as we...

Leukocytes recruited during ischemia-reperfusion to the liver are important mediators of injury. However, the mechanisms of leukocyte adhesion and the role of adhesion receptors in hepatic vasculature remain elusive. L-selectin may critically contribute to injury, priming adhesion for later action of intercellular adhesion molecule-1 (ICAM-1). Paired experiments were performed using mutant mice (L-selectin −/−, ICAM-1 −/−, and L-selectin/ICAM-1 −/−) and wild-type mice (C57BL/6) to investigate leukocyte adhesion in the ischemic liver. Leukocyte adhesion and infiltration were assessed histologically. Aspartate aminotransferase levels were significantly reduced (2- to 3-fold) in mutant vs. wild-type mice in most groups but most significantly after 90 min of partial hepatic ischemia. Leukocyte adhesion was significantly reduced in all mutant mice. Areas of microcirculatory failure, visualized by intravital microscopy, were prevalent in wild-type but virtually absent in L-selectin-deficient mice. After total hepatic ischemia for 75 or 90 min, survival was better in mutant L-selectin and L-selectin/ICAM-1 mice vs. wild-type mice and ICAM-1 mutants. In conclusion, L-selectin is critical in the pathogenesis of hepatic ischemia-reperfusion injury. Poor sinusoidal perfusion due to leukocyte adhesion and clot formation is a factor of injury and appears to involve L-selectin and ICAM-1 receptors.