Traumatic paraplegia in snowboarders

STUDY DESIGN: Patients with traumatic paraplegia resulting from snowboarding accidents were reviewed. OBJECTIVE: To understand the clinical features and mechanisms of paraplegic snowboarding injuries. SUMMARY OF BACKGROUND DATA: The recent explosion in the popularity of snowboarding has resulted in dramatically increased numbers of snowboarding injuries. However, little information is available as to the types and mechanisms of snowboard-related spinal injuries and their neurologic involvement. METHODS: The subjects of this study were six male patients, with an average age of 23.7 years, referred to the authors' institution for neurologic deficits associated with spinal injuries between January 1996 and March 1999. The clinical features of these patients were reviewed with respect to the mechanism of the injury, fracture pattern, neurologic status, treatment, and clinical outcome. The mean follow-up period was 23.7 months. RESULTS: The six snowboarders with traumatic paraplegia constituted a very homogenous group with the following features: They were all young men between the ages of 23 and 25 years. All the injuries had occurred at the vertebral junctions. The primary mechanism of the fractures was a backward fall from an intentional jump. The fracture patterns were of the flexion-distraction type. These homologous features suggest that this snowboarding group is at high risk for severe spinal injury. CONCLUSION: The high risk of traumatic paraplegia for a group within the snowboarding population requires the development and provision of injury prevention strategies specific to this group.     

Regulation of branched-chain alpha-keto acid dehydrogenase kinase expression in rat liver

Branched-chain amino acids are toxic in excess but have to be conserved for protein synthesis. This is accomplished in large part by control of the activity of the branched-chain alpha-keto acid dehydrogenase complex by phosphorylation/dephosphorylation. Regulation of the activity of the hepatic enzyme appears particularly important, at least in rats, since an exceptional high activity of the complex in this tissue makes the liver the primary clearing house for excess branched-chain alpha-keto acids released by other tissues. The degree to which the branched-chain alpha-keto acid dehydrogenase complex is inactivated by phosphorylation is determined by the activity of the branched-chain alpha-keto acid dehydrogenase kinase, which is itself regulated by allosteric effectors as well as factors that affect its level of expression. Well established among these are the alpha-keto acid produced by leucine transamination, which is a potent inhibitor of the kinase, and starvation for dietary protein, which causes increased expression of the branched-chain alpha-keto acid dehydrogenase kinase. The latter finding resulted in the working hypothesis that nutrients and hormones regulate expression of the branched-chain alpha-keto acid dehydrogenase kinase. Evidence has been obtained for the involvement of thyroid hormone, glucocorticoids and ligands for peroxisome proliferator-activated receptor alpha. Thyroid hormone induces, whereas glucocorticoids and peroxisome proliferator-activated receptor alpha ligands repress, expression of the kinase. Increased blood levels of thyroid hormone are proposed to be responsible for increased expression of branched-chain alpha-keto acid dehydrogenase kinase in animals starved for protein.     

Pharmacological discrimination between effects of carbamazepine on hippocampal basal, Ca(2+)- and K(+)-evoked serotonin release

To elucidate mechanisms of hippocampal serotonin release and possible mechanisms of clinical action of carbamazepine (CBZ), we determined interaction between antagonists of N-type (omega-conotoxin GVIA:GVIA), P-type (omega-agatoxin IVA:IVA) Ca(2+) channels, Na(+) channel (tetrodotoxin: TTX) and CBZ on hippocampal basal, Ca(2+)- and K(+)-evoked serotonin releases, using microdialysis in freely moving rats. Basal release was reduced by TTX, GVIA and IVA (GVIA>IVA). Ca(2+)-evoked release was reduced by GVIA but unaffected by TTX and IVA. K(+)-evoked release was reduced by TTX, GVIA and IVA (GVIA相似文献   

Effect of E3040, an inhibitor of 5-lipoxygenase and thromboxane synthase, on rat bowel damage induced by lipopolysaccharide

Intravenous administration of lipopolysaccharide to rats that had been immunized with lipopolysaccharide induced hemorrhagic damage in the large intestine. We investigated the role of 5-lipoxygenase and thromboxane synthase products in the damage of the large intestine induced by lipopolysaccharide. In the large intestine of lipopolysaccharide-immunized rats, intravenous injection of lipopolysaccharide increased the vascular permeability, production of leukotriene B(4), leukotriene C(4)/D(4), thromboxane B(2) and prostaglandin E(2), and also increased the activity of myeloperoxidase, a marker enzyme of neutrophils. Oral administration of E3040 (6-hydroxy-5,7-dimethyl-2-(methylamino)-4-(3-pyridylmethyl)benzothiazole), a novel dual inhibitor of 5-lipoxygenase and thromboxane synthase, at 30 and 100 mg/kg inhibited the increase in vascular permeability induced by lipopolysaccharide in the large intestine. E3040 inhibited the production of leukotriene B(4) and thromboxane B(2) and tended to increase the production of prostaglandin E(2) in the large intestine. Sulfasalazine (500 mg/kg) and prednisolone (10 mg/kg), drugs used for the treatment of inflammatory bowel disease, had no significant effect on eicosanoid production and vascular permeability. These results indicate that E3040 inhibits the production of both leukotriene B(4) and thromboxane B(2) and prevents lipopolysaccharide-induced damage in the large intestine of lipopolysaccharide-immunized rats.     

Application of pressure-controlled colon delivery capsule to oral administration of glycyrrhizin in dogs

A colon delivery system has been used to improve the bioavailability of glycyrrhizin, a glycoside of glycyrrhetic acid. The bioavailability of glycyrrhizin is low when administered in conventional oral galenic dosage forms because glycyrrhizin is enzymatically hydrolysed both in the stomach and in the intestine. It was reasoned that if large amounts of glycyrrhizin were directly delivered to the colon, enzymatic activity should be reduced due to saturation so that intact glycyrrhizin could be absorbed into the systemic circulation. Based on this assumption, pressure-controlled colon delivery capsules (PCDCs) were used as a colon delivery system. Eight types of glycyrrhizin solution were prepared and were introduced into PCDCs. After oral administration of the test PCDCs to beagle dogs, blood samples were obtained over 24 h and plasma glycyrrhizin concentrations were measured by an HPLC method. With PCDCs containing aqueous glycyrrhizin and propylene glycol solutions, plasma glycyrrhizin levels were extremely low and the bioavailabilities of glycyrrhizin were 0.6% and 0.4%, respectively. When Labrasol was added to both types of glycyrrhizin solution, the bioavailability was improved to 4.6% for aqueous solution and 3.8% for propylene glycol solution. When a surfactant, Polysorbate 80, was added in combination with Labrasol, synergistic effects were not obtained. Furthermore, dose-dependent effects of Polysorbate 80 were not obtained. Labrasol, which is a component of self-emulsifying drug delivery systems (SEDDS), has been shown to strongly improve the bioavailability of glycyrrhizin from the colon.     

Acute up-regulation of brain-derived neurotrophic factor expression resulting from experimentally induced injury in the rat spinal cord

Brain-derived neurotrophic factor (BDNF), a member of the nerve growth factor family of trophic factors, has multiple functions including a role in the promotion of neuronal survival and nerve fiber elongation in both the central and the peripheral nervous systems. We assessed the expression of endogenous BDNF following an experimentally induced compression injury to the spinal cord. Expression of BDNF mRNA was increased following the spinal cord injury; reaching maximum levels 24 h after the injury. Expression of BDNF mRNA returned to the levels observed in sham-operated control animals within 3 days of the injury. Using the in situ hybridization technique, we observed a wide distribution of BDNF expression among the different cell types in the spinal cord, including motor and sensory neurons, and in glia cells, including astrocytes. We also observed expression of BDNF in putative macrophages and/or microglia; however, this effect was not observed until day 7 following spinal cord injury. These results suggest that BDNF is synthesized in both neurons and astrocytes during the acute response to injury to the spinal cord, functioning in a mainly neuroprotective role. This is followed by a later phase of expression in which BDNF is produced by macrophages and/or microglia, apparently functioning in a restorative capacity.     

The outcome of volume reduction surgery according to the underlying type of emphysema

Lung volume reduction surgery (VRS) is widely performed to improve symptoms in patients with severe pulmonary emphysema; however, it remains unclear whether or not the underlying type of emphysema affects the surgical results. A total of 58 patients with advanced symptomatic emphysema underwent thoracoscopic VRS of emphysematous lung tissue. The resected lung tissue was examined microscopically, and the patients were classified into two groups according to the predominant pathological findings, as having either centrilobular-type or panacinar-type emphysema. A predominant pathological type was identified in only 34 patients (59%), 19 of whom had centrilobular-type emphysema and 15, panacinar-type emphysema. Patients with predominately panacinar emphysema had more compromised total lung capacity and residual volume than those with centrilobular emphysema. Significant improvements in forced expiratory volume in 1 s were evident 3 months after surgery in the group with centrilobular emphysema (+515 ± 141 ml) compared with that in the group with panacinar-type emphysema (+109 ± 40 ml, P = 0.03). The results of lung VRS were found to depend on the underlying type of emphysema, as the benefits of surgery for panacinar emphysema were less marked than those for centrilobular emphysema. Received: February 25, 2000 / Accepted: March 6, 2001     

Fibrous connection to bone after immediate repair of the canine infraspinatus: the most effective bony surface for tendon attachment

The purpose of this histologic study was to identify the most effective bony surface for fibrous connection to bone after immediate repair of the canine infraspinatus. Light microscopic views were used to evaluate collagen fiber development. The left infraspinatus tendon of 15 dogs was transected and repaired to 3 different bone surfaces: a tendon end adjacent to the tendon insertion (group 1, n = 5), a calcified fibrocartilage layer (group 2, n = 5), and a cancellous surface (group 3, n = 5). Tendon repair to distal tendon ends restored the 4-layered enthesis in the healing period, whereas tendon repair to the calcified fibrocartilage layer considerably delayed fiber development into bone. Fiber connection to cancellous surface developed according to the remodeling of trabecular bone. Secure fiber connection into the thickened trabecular bone developed by 16 postoperative weeks. On the basis of these results, in clinical settings, ruptured tendon ends should be attached to the remaining distal tendon end or to a cancellous surface; they should not be attached to a calcified fibrocartilage layer.     

Laparoscopic biliopancreatic diversion with a duodenal switch for morbid obesity: a feasibility study in pigs

BACKGROUND and PURPOSE: Biliopancreatic diversion with a duodenal switch is an emerging open procedure that appears as effective as other bariatric operations. Our goal was to determine the safety and feasibility of performing this procedure using a laparoscopic approach in a porcine model. MATERIALS and METHODS: Six 50-kg pigs underwent surgery. Intake was restricted with a sleeve gastrectomy, and malabsorption was obtained by creating a Roux-en-Y. The Roux limb served as a 150-cm alimentary channel following anastomosis to a transected proximal duodenum, while the other limb, or biliopancreatic channel, transported digestive juices. Where the two limbs joined, a 100-cm common channel was formed. RESULTS: The operation was completed in a mean time of 4.5 hours. Two of the six pigs had an intraoperative duodenoenterostomy anastomotic leak detected on methylene blue testing. This leakage was thought to be related to pig anatomy and is not expected to be a problem in humans. At necropsy, all anastomoses were patent, and there were no enteroenterostomy leaks or mesenteric torsions. CONCLUSION: On the basis of the porcine model, laparoscopic biliopancreatic diversion with a duodenal switch is anticipated to be feasible and safe in humans. Substantial weight loss combined with the benefits of laparoscopic surgery can be expected.     

Myxomatous degeneration of the ligamentum flavum of the lumbar spine

STUDY DESIGN: Report of two cases of acute lumbar nerve root compression caused by myxomatous degeneration of the ligamentum flavum. OBJECTIVE: To report a rare cause of acute lumbar nerve root compression. SETTING: Orthopaedic department, Osaka, Japan. SUMMARY OF BACKGROUND DATA: Two patients, both 50-year-old men presenting with signs and symptoms suggestive of acute lumbar nerve root compression were found to have a ligamentum flavum mass. The masses were removed and the patients regained normal function postoperatively. METHODS: To reveal the nature of the mass, histopathological studies were made. Continuous sections were prepared from the removed mass lesions. The sections were stained with hematoxylin and eosin, van Gieson's stain, azan stain, periodic acid Schiff reaction, Alcian blue stain and von Kossa's stain. RESULTS: Histological examination revealed myxomatous degeneration of the ligamentum flavum. No elastic fibers were found at the degeneration site. Diffuse mucopolysaccharide deposition was found at the degeneration site, however, no cyst was found. Collagen fibers were not increased. Hypertrophy or ossification of the ligamentum flavum was not recognized in the sections. At a follow-up examination over 2 years later, the patients were free of symptoms and the findings of a neurological examination were normal. CONCLUSION: Two cases of myxomatous degeneration of the ligamentum flavum of the lumbar spine were reported, which have seldom been described as the cause of acute lumbar nerve root compression.