Effect of nitric oxide on the contractile function of rat reperfused skeletal muscle

BACKGROUND: The involvement of nitric oxide (NO) in ischemia-reperfusion injury remains controversial and has been reported to be both beneficial and deleterious. The purpose of this study was to examine the contribution of NO and superoxide to skeletal muscle function using an ischemic revascularized hind limb model in rats. PATIENTS AND MATERIALS: Warm ischemia produced by vascular pedicle clamping was sustained for 3 h. The animals were divided into four groups according to the solution administrated: (1) saline, (2) N-methyl-L-arginine acetate (L-NMMA), (3) L-NMMA + N-(N-L-g-glutamyl-S-nitroso-l-cysteinyl)glycine (S-nitrosoglutathione), or (4) superoxide dismutase (SOD). Saline, L-NMMA, or L-NMMA + S-nitrosoglutathione was infused for the first 2 h of reperfusion. The SOD was administered as an intravenous bolus 5 min before the onset of reperfusion. Postischemic blood flow was measured by a Doppler flow meter. Muscle contractile function was determined after 24 h of reperfusion. RESULTS: Postischemic blood flow was significantly decreased by the L-NMMA infusion compared with that in the saline-treated group. No significant difference in postischemic blood flow was noted in the saline-, L-NMMA + S-nitrosoglutathione-, and SOD-treated groups. Contractile function of the gastrocnemius muscle in the L-NMMA-and SOD-treated groups, but not in the L-NMMA + S-nitrosoglutathione group, was significantly better than that in the saline-treated group. CONCLUSION: Limiting postischemic blood flow and SOD infusion are both beneficial in decreasing the ischemia-reperfusion injury of skeletal muscle. S-Nitrosoglutathione infusion following suppression of endogenous NO production does not reduce ischemia-reperfusion injury.     

L-arginine and nitroglycerin restore hypercapnia-induced cerebral vasodilation in rabbits after its attenuation by ketamine

Although it has been reported that ketamine attenuates hypercapnia-induced cerebral vasodilation, the mechanism remains unknown. Because nitric oxide is involved in cerebral CO2 reactivity, we studied the effects of L-arginine and nitroglycerin on ketamine-mediated attenuation of vascular responses to hypercapnia. Under pentobarbital anesthesia, 16 rabbits underwent closed cranial window preparation. Hypercapnic challenges were repeated after IV saline, ketamine (10 mg/kg, followed by 20 mg x kg(-1) x h(-1)), or ketamine plus either L-arginine (150 mg/kg, followed by 100 mg x kg(-1) x h(-1); n = 8) or nitroglycerin (5 microg x kg(-1) x min(-1) infusion; n = 8). Ketamine reduced hypercapnia-induced cerebral vasodilation (1.27%/mm Hg +/- 0.45%/mm Hg [saline] versus 0.82%/mm Hg +/- 0.53%/mm Hg [ketamine]: P < 0.05), but L-arginine restored reactivity (1.28%/mm Hg +/- 0.73%/mm Hg: P < 0.05 versus ketamine), as did nitroglycerin (1.14%/mm Hg +/- 0.73%/mm Hg [saline] versus 0.56%/mm Hg +/- 0.63%/mm Hg [ketamine]: P < 0.05, and 1.15%/mm Hg +/- 0.74%/mm Hg [ketamine plus nitroglycerin]: P < 0.05 versus ketamine). This indicates that ketamine attenuates cerebral CO2 reactivity, at least in part, via suppression of nitric oxide-cyclic guanosine monophosphate mechanisms in the cerebral vasculature. IMPLICATIONS: The attenuation of cerebral vasodilation to hypercapnia seen under ketamine anesthesia is reversed by L-arginine or nitroglycerin infusion.     

New titanium spacer for cervical laminoplasty: initial clinical experience. Technical note

Many commercially available hydroxyapatite (HA) spacers for cervical laminoplasty have been introduced but have disadvantages such as lack of plasticity, easy cracking, and occasional difficulty in fixation by sutures. Here we present the short-term results of a newly designed titanium spacer (Laminoplasty Basket) in open-door cervical laminoplasty, and evaluated clinically and radiologically. The titanium box-shaped spacer with two arms for fixation was easily inserted and fixed into the laminoplasty space with 4-mm or 5-mm length screws after the posterior cervical arch was repositioned for the canal expansion. Twenty-one patients with cervical myelopathy due to spondylosis or ossification of the longitudinal ligament or developmental narrow canal observed for more than 6 months postoperatively were enrolled in this study. The neurological condition of these patients improved from 9.4 points on the Japanese Orthopaedic Association scale preoperatively to 13.5 points at 6 months after surgery. Postoperative radiological evaluation showed no laminar closure or implant failure and cervical spine curvature was maintained. These results seemed to have no significant difference compared with those using HA spacers. This titanium spacer is a potential substitute for conventional HA or other similar devices in cervical laminoplasty.     

Specific Antibiotic Prophylaxis Based on Bile Cultures Is Required to Prevent Postoperative Infectious Complications in Pancreatoduodenectomy Patients Who Have Undergone Preoperative Biliary Drainage

Background Preoperative biliary drainage (PBD) is associated with bacterial contamination of bile, but the effects of PBD on morbidity after pancreatoduodenectomy remain controversial. The aim of this study was to characterize bile contamination to develop successful specific antibiotic prophylactic strategies for pancreatoduodenectomy. Methods Ninety-one consecutive patients who underwent pancreatoduodenectomy for periampullary tumor were prospectively evaluated. Prophylactic antibiotics were selected based on preoperative bile cultures. Bile cultures and postoperative complications were compared in 46 patients who underwent PBD (drainage group) versus 45 patients who did not (nondrainage group). Results The incidence of positive bile cultures was higher in the drainage group (78%) than in the nondrainage group (36%) (P < 0.001). In the drainage group, positive bile cultures were frequently polymicrobial (61%) and demonstrated resistance to several antibiotics, including cefazolin (83%), cefmetazole (72%), and cefpirome (64%). Overall morbidity (30% and 22%) and infectious morbidity (13% and 11%) did not differ significantly between the drainage and nondrainage groups, respectively. Conclusions PBD had a notable influence on bile microbial contamination, including a higher rate of antibiotic resistance. Therefore, specific antibiotic prophylaxis based on bile culture is required for preventing infectious complications in pancreatoduodenectomy patients who undergo PBD.     

Choroid plexus ependymal cells host neural progenitor cells in the rat

We previously demonstrated that choroid plexus epithelial (modified ependymal) cells (CPECs) differentiated into astrocytes after grafting into the spinal cord. In the present study, we examined whether CPECs from rats at postnatal 1 day (P1), 7 day (P7), and 8 weeks (P8W) can function as neural progenitor cells that give rise to neurons and glial cells. Cell spheres were produced in cultures of whole tissue of the choroid plexus from the fourth ventricle of rats at each postnatal period. beta-tubulin class III (Tuj-1), glial fibrillary acid protein (GFAP)-, and O4-positive cells differentiated from cell spheres in the differentiation medium. We produced a monoclonal antibody 3E6 specifically labeling microvilli of CPECs. Using this monoclonal antibody, CPECs were isolated from the choroid plexus of P8W rats by cell sorter (FACS). Immunocytochemistry confirmed that there was no contamination from fibroblasts, endothelial cells, macrophages, or Schwann cells in the FACS-isolated 3E6-labeled cells. Cell spheres formed in the cultures of these 3E6-labeled CPECs. After expansion, these cell spheres gave rise to Tuj-1- (5%), GFAP- (45%), and O4-positive cells (0.16%). The remaining cells (45%) were unlabeled neural or glial markers. Some CPECs of the P8W rat were immunohistochemically stained with lineage-associated markers of Musashi-1 and epidermal growth factor-receptor (EGF-R). In addition, infusion of EGF or fibroblast growth factor-2 (FGF2) into the ventricle increased the number of bromodeoxyuridine (BrdU)-positive cells among CPECs from 0.03% (untreated) to 1.14% (38-fold, EGF) and 1.03% (35-fold, FGF2), respectively. These findings indicate that neural progenitor cells exist among CPECs in the rat.     

Inhibition of integrin alphavbeta3 reduces blood-brain barrier breakdown in focal ischemia in rats

Ischemic stroke is a major cause of morbidity and mortality in industrialized nations. We tested the effect of postischemic treatment of cyclo-RGDfV (cRGDfV), a selective inhibitor of integrin alphavbeta3, in the middle cerebral artery occlusion (MCAO) model of ischemic stroke in rats. Rats were randomly divided into three groups: sham operation (n = 13), MCAO with no treatment (n = 18), and MCAO with cRGDfV treatment (n = 28). Focal ischemia was induced with the suture occlusion method for 2 hr, and treatment was given 1 hr after reperfusion (3 hr after ischemia). All animals were sacrificed 24 hr after reperfusion. Assessment included neurological scores, infarction volumes, brain water content, Evans blue exudation, IgG exudation, histology, immunohistochemistry, and Western blotting. Treatment with cRGDfV ameliorated neurological deficits, reduced brain edema, and reduced exudation of Evans blue dye and IgG, but failed to reduce infarction volumes. Western blotting showed a reduction in phosphorylation of one subset of vascular endothelial growth factor (VEGF) receptors in the cRGDfV treatment group. Western blotting also demonstrated a significant reduction of fibrinogen in the cRGDfV treatment group. We conclude that poststroke treatment with cRGDfV reduces blood-brain barrier breakdown in focal ischemia, possibly through inhibition of VEGF-mediated vascular breakdown.     

High-grade invasive urothelial carcinoma with focal plasmacytoid differentiation successfully treated by transurethral resection followed by chemoradiotherapy

We report a case of high-grade invasive urothelial carcinoma with plasmacytoid differentiation of the urinary bladder. A 75-year-old woman was referred to our hospital because of macroscopic hematuria. Cystoscopy detected a solid pedunculated bladder tumor, and a transurethral resection of the bladder tumor (TUR-Bt) and the image findings showed pT1N0M0 bladder cancer. The histopathological examination revealed the coexistence of a large component of high-grade invasive urothelial carcinoma and a small component of plasmacytoid carcinoma. Following the TUR-Bt, external beam radiotherapy and chemotherapy with gemcitabine and nedaplatin were carried out. The bladder tumor has not recurred for 2 years after the TUR-Bt.     

Cricopharyngeal myotomy for primary cricopharyngeal dysfunction caused by a structural abnormality localized in the cricopharyngeus muscle: Report of a case

Primary cricopharyngeal dysfunction (PCD) is a rare idiopathic disorder of the upper esophageal sphincter (UES), characterized by oropharyngeal dysphagia, frequent aspiration, and narrowing at the level of the UES. Cricopharyngeal myotomy (CPM) has been used to treat oropharyngeal dysphagia of different causes including anatomic, neuromuscular, iatrogenic, inflammatory, neoplastic, and idiopathic; however, the indications for CPM and predictors of its outcome are not clearly defined. We report a case of PCD with hypertonic UES caused by a structural abnormality localized in the cricopharyngeus muscle, visualized as a cricopharyngeal bar, which we treated successfully by CPM, achieving long-term relief.