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Lei Tian,1 Li-Sheng He,1 Bhavesh Soni,2 Hong-Tao Shang11Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, China; 2Maxillofacial Unit, Morriston Hospital, Swansea, Wales, UKAbstract: Osteoradionecrosis (ORN) in the head and neck area is the most devastating long-term complication of radiotherapy, with slow progression and inability to heal spontaneously. ORN can lead to intolerable pain, fractures, and sequestration of devitalized bone and fistulae, making oral feeding impossible and causing facial deformation. In spite of its notorious reputation over at least 90 years, the precise pathogenesis of ORN has not been fully clarified, which has led to obstacles in the management of the disease. Several theories about its pathogenesis have been formulated, and radiation-induced fibrosis is the newest one. According to this theory, ORN is essentially a type of fibrosis induced by radiotherapy, and antifibrosis therapy has been shown to be effective in its treatment. We assumed that ORN, like fibrosis in other organs, is the result of a process of fibrogenesis in which myofibroblasts are the key effector cells. The uninterrupted accumulation of myofibroblasts and consequent persistent excess production of collagenous extracellular matrix and tensile force result in loss of normal function and ultimately radiation-induced fibrosis. During this process, myofibroblasts may be protected from apoptosis by acquiring an immune-privileged capacity, which allows continuous matrix synthesis. If this hypothesis proves to be correct, it would enable better understanding of the cellular and molecular mechanisms underlying the pathogenesis and progression of ORN, and would help improve our ability to prevent occurrence of ORN, give an earlier diagnosis, and treat it more effectively.Keywords: osteoradionecrosis, apoptosis, fibrosis, mandible, myofibroblast

The National Grid Project has been under development at the NSF Engineering Research Center at Mississippi State University since 1991. A summary of the progress to date is presented. The project utilizes Non-Uniform Rational B-Splines (NURBS) for the geometry with a solid modeling Boundary Representation (B-Rep) data structure to represent topology. Geometry can be imported into the system via the Initial Graphics Exchange Specification (IGES), discrete XYZ's (interpolated into NURBS), or can be internally created by CAD operations. The NURBS are used parametrically both the structured and unstructured grid generation. Volumetric structured and unstructured grids are generated, visualized, and evaluated within the program, allowing the user the flexibility and control of the grid process.

The B-spline approximation techniques applicable to surface grid generation pertinent to computational field simulations are presented. A systematic procedure to first correct design process errors and then unite selected surface patches yielding an overall continuous approximation is developed. The applications of these techniques to surface grid redistribution, automatic remapping, and elliptic refinement is presented.

Vaidyanathan Subramanian, Bakulesh Madhusudan Soni Northwest Regional Spinal Injuries Centre, Southport and Formby District General Hospital, Southport, UKCorrespondence: Vaidyanathan Subramanian, Email subramanian.vaidyanathan@merseywestlancs.nhs.ukMethods: We used a Urethrotech catheterisation device in 57 male patients with spinal cord injury, in whom urethral catheterisation was unsuccessful or previous catheterisation was difficult.Results: Urethrotech catheter could be inserted in 51 patients. No patient developed urinary tract infection. In one patient, the guidewire could not be introduced into the bladder, and a coude Foley catheter was inserted. In two patients, the guidewire was inserted into the bladder, but a 16 CH catheter could not be advanced over the guidewire. Emergency suprapubic cystostomy was performed in one case; in the other, urethral stricture was dilated; a size 12 CH catheter was inserted. In three patients, the guidewire curled back into the urethra because of severe spasm of the urethral sphincter. Catheterisation with a Tiemann catheter was successful after administration of diazepam and/or stretching of the anal sphincter by another health professional, which caused reflex relaxation of the urethral sphincter. Complications of Urethrotech catheterisation included urethral bleeding, haematuria, pain, doubling back of the guidewire due to spasm of the urethral sphincter or from an empty bladder. We adopted variations in technique, eg filling the bladder with saline prior to catheterisation when feasible, insertion of the guidewire by the side of the old catheter, use of Tiemann tip catheters, administration of antibiotics, diazepam to control spasms, nifedipine to control autonomic dysreflexia, analgesics, stretching of the anal sphincter to induce reflex relaxation of the urethral sphincter, urgent imaging studies to confirm correct positioning of the catheter, omitting anticoagulants and monitoring patients, who developed bleeding.Conclusion: Use of Urethrotech in spinal injury patients warranted adaptations to the technique, which required expertise, experience, and backup facilities. To ensure patient safety, Urethrotech catheter should be used in a hospital setting, and by medical personnel with experience in the management of spinal cord injury patients.Keywords: urethral catheterisation, male, patient, urinary bladder, urethral sphincter, paraplegia, patient safety

Vaidyanathan Subramanian, Bakulesh Madhusudan Soni Regional Spinal Injuries Centre, Southport and Formby District General Hospital, Town Lane, Southport, Merseyside, PR8 6PN, UKCorrespondence: Vaidyanathan Subramanian, Email subramanian.vaidyanathan@nhs.netAbstract: We used a safety-valve (Trans-Urethral Catheterisation Safety Valve, Class Medical, Limerick, Ireland) to prevent urethral trauma due to inflation of the anchoring balloon in the urethra during catheterisation of male spinal cord injury patients in a spinal unit. The safety-valve is attached to the balloon channel of a Foley catheter. If the balloon is inflated when it is in the urethra, the pressure valve is activated. Any fluid pushed into the balloon channel leaks out and balloon inflation stops, indicating that the balloon is not inside the bladder. The safety-valve was used in 44 catheterisations. There was leakage of water during three catheterisations. In the first case, the health professional did not inflate and deflate the balloon prior to its use. This “pre-valve inflation” step overcomes the baseline resistance pressure of the balloon and prevents fluid leaking from the valve when the catheter is in the correct position. In the second instance, the valve was found to be defective. In the third case, the catheter had been misplaced; it was removed and repositioned; there was no leakage of water during inflation of the balloon. In one out of 44 catheterisations, the catheter had been misplaced; leakage of water from the safety-valve stopped inflation of the balloon and prevented iatrogenic urethral trauma. The safety-valve may be used during catheterisation of male patients in the spinal unit to prevent urethral trauma caused by inflation of the balloon of Foley catheter in the urethra. However, health professionals should remember the few shortcomings of the catheter safety-valve.Keywords: spinal cord injury, urethral catheterisation, patients, iatrogenic, catheter, urethra

The cross-section of 186W(n,γ)187W reaction has been measured at an average neutron energy of 20.02±0.58 MeV by using activation technique. The 27Al(n,α)24Na and 115In(n,n')115mIn reactions have been used for absolute neutron flux measurement. Theoretically the reaction cross-sections have been calculated by using the TALYS-1.9 code. The results from the present work and the EXFOR based literature data have been compared with the evaluated data and calculated data from TALYS-1.9 code. [ABSTRACT FROM AUTHOR]