Nitric oxide mediated effects of nebivolol in myocardial infarction: the source of nitric oxide.

OBJECTIVE: After MI pathological LV remodeling is one of the major causes of death. We previously showed the NO mediated beneficial effects of nebivolol in rat MI model, in this study we aimed to evaluate the NOS related mechanisms in this phenomenon. MATERIALS AND METHODS: Rats were divided into four groups: sham operated (sham-control), MI-induced (MI-control), immediate nebivolol loaded (MI-neb1), orally nebivolol treated (MI-neb2). MI was induced by the ligation of the LAD. Loading dose of nebivolol (0.1 mg/kg) was administrated i.v. during reperfusion and continuation dose was administrated orally (2 mg/kg) by gastric gavages once daily. NOS related mechanisms were assessed either in acute (2nd day) and sub-acute (28th day) period of MI by histologic, hemodynamic and biologic studies. RESULTS: Compared to MI-control rats, physiological functions of LV (LVEDP, Δ±dp/dt) were prevented in both nebivolol treated groups. Improvements in anatomical parameters (LEV, HW, LVW/HW) were consistent with functional improvement too. Moreover, oxidative (characterized by decreased MDA and increased SOD levels) and nitrosative (characterized by decreased ONOO- levels) damage were limited in these groups. Compared to MI-control rats, most marked change was seen in the nNOS labelling in the nebivolol treated groups. The decrease in iNOS labelling was also prominent in these groups too. CONCLUSIONS: NOS mediated mechanisms of nebivolol can be summarized as: 1) diminishing iNOS expression together with restoration of MI induced eNOS activation both in vascular bed and myocytes at the acute period of MI, and 2) prevention of deterioration in nNOS expression in myocardial cells at the sub-acute period of MI.

Effects of lipopolysaccharide on the blood-brain barrier permeability in prolonged nitric oxide blockade-induced hypertensive rats.

The authors investigated the effects of lipopolysaccharide (LPS) on the blood-brain barrier (BBB) integrity and the activity of astrocytes during the Nw-nitro-L-arginine methyl ester (L-NAME) hypertension followed by angiotensin (ANG) II in rats. They measured the changes in the BBB permeability using the Evans blue (EB) dye and concomitantly in the levels of TNF-a, IL-1b, and IL-6 in serum and nitric oxide in plasma. The authors performed two tight junction-specific proteins, zonula occludens-1 and occludin, and glial fibrillary acidic protein, by using immunohisto-chemical method. The serum levels of TNF-a, IL-1 IL-6, and the plasma level of nitric oxide significantly increased in LPS-treated rats (p<.01). The EB dye extravasation increased in cerebellum (p<.001) and diencephalon (p<.05) of L-NAME plus ANG II-treated animals. However, LPS reduced the increased EB dye extravasation in the brain regions of L-NAME-induced hypertensive rats treated with ANG II (p<.001). In L-NAME, there was a considerable loss of staining in both zonula occludens-1 and occludin. Staining for zonula occludens-1 and occludin was highly intensive in animals treated with LPS. Glial fibrillary acidic protein staining was seen in a few astrocytes in brains of L-NAME-treated animals. However, this staining showed an increased intensity in the brain sections of animals treated with LPS. This study indicates that, in L-NAME hypertensive rats, ANG II leads to an increase in the extravasation of EB dye to brain as a result of decreased activity of tight junction proteins and astrocytes, and LPS could significantly attenuate the EB dye transport to the brain through the increased activity of tight junction proteins and astrocytes.

Evaluation of ultrastructural changes in paranasal sinus mucosa after functional endoscopic sinus surgery in patients with chronic rhinosinusitis.

The purpose of this study was to compare the preoperative and postoperative ultrastructural changes of paranasal sinus mucosa in patients treated with functional endoscopic sinus surgery for chronic rhinosinusitis. Twelve patients undergoing functional endoscopic sinus surgery for the treatment of chronic rhinosinusitis were involved. The ethmoid sinus mucosa was sampled during the operation and approximately 6 months after the operation. The ciliated epithelium of sinus mucosa was evaluated with transmission electron microscopy. The samples were taken at the Otolaryngology Department of Istanbul University School of Medicine. Electron microscopic study was performed at the Histology and Embryology Department of the same University. Preoperatively, ciliated epithelial cells of the sinus mucosa of the patients showed degenerated ultrastructure with decreased number of cilia, cytoplasmic protrusions, cisternal dilatations of endoplasmic reticulum, and mitochondrial swellings. Remnants of degenerated cells and cellular separations at cell junctions were evident in the diseased epithelium. Goblet cells were frequent along the epithelial lining. Postoperatively, normal architecture and ultrastructure of the ciliated epithelium was restored. These observations showed that unlike other surgical operations, paranasal sinus mucosa can regenerate and the ciliated epithelium can return to normal after functional endoscopic sinus surgergy.

MRI of cerebral alveolar echinococcosis.

Cerebral alveolar echinococcosis is rare. We report a case with multiple intracranial masses which show cauliflower-like contrast enhancement pattern on MRI. The lesions originated from hepatic involvement with invasion of the inferior vena cava.

Participation of CD45, NKR-P1A and ANK61 antigen in rat hepatic NK cell (pit cell)mediated target cell cytotoxicity.

AIM:Several triggering receptors have been described to be involved in natural killer (NK) cell-mediated target cytotoxicity. In these studies, NK cells deriv ed from blood or spleen were used. Pit cells are liver-specific NK cells that possess a higher level of natural cytotoxicity and a different morphology when compared to blood NK cells. The aim of this study was to characterize the role of the NK triggering molecules NKR P1A, ANK61 antigen, and CD45 in pit cell medi ated killing of target cells.METHODS:( 51) Crrelease and DNA fragmentation were used to quantify target cell lysis and apoptosis, respectively.RESULTS:Flow cytometric analysis showed that pit cells expressed CD45, NK R P1A, and ANK61 antigen. Treatment of pit cells with monoclonal antibody (mAb)to CD45 (ANK74) not only inhibited CC531s or YAC 1 target lysis but also apopt osis induced by pit cells. The mAbs to NKR P1A (3.2.3) and ANK61 antigen (ANK61 )had no effect on pit cell mediated CC531s or YAC 1 target cytolysis or apopto sis, while they did increase the Fcgamma receptor positive (FcgammaR(+)) P815 cytolysi s and apoptosis. This enhanced cytotoxicity could be inhibited by 3,4 dichloroi socoumarin, an inhibitor of granzymes.CONCLUSION:These results indicate that CD45 participates in pit cell med iated CC531s and YAC-1 target cytolysis and apoptosis. NKR-P1A and ANK61 antigen on pit cells function as activation structures against Fc gammaR( +) P 815 cells, which was mediated by the perforin/granzyme pathway.