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BackgroundCT coronary angiography (CTCA) is an emerging diagnostic tool in the assessment of patients with suspected coronary artery disease. It has several advantages over conventional coronary angiography (CCA); however, its use is not yet widespread in large teaching centres.AimsTo determine what proportion of patients who have CTCA, do not require subsequent CCA.MethodsA prospective analysis of all patients referred for CTCA from the start of the service in January 2008 to April 2010.ResultsCTCA provided definitive diagnostic images in 85% of patients. Overall only 12% (n?=?33) of patients had subsequent CCA. The proportion of patients who subsequently had CCA reduced with time reflecting increasing confidence with the clinical service.ConclusionsA CTCA service can be successfully established out with a large teaching centre hospital. Close working between cardiologists and radiologists leads to increased confidence in the service and obviates the need for CCA in a large proportion of patients.

AIMS: The aims of the present study were to characterise the renal effects of the α2-adrenergic agonist, xylazine, in the rat and to test the role of changes in glomerular filtration rate, glucosuria, and arginine vasopressin (AVP) in its mechanism of action.METHODS: Male Wistar rats were anaesthetised with pentobarbitone sodium (50 mg/kg), and polyethylene cannulae were surgically placed for blood pressure measurement and for blood and urine collection. Rats were given xylazine and other α2 agonists by bolus intravenous dose, and the effects of the drugs were monitored in the presence and absence of the selective α2 antagonist, yohimbine, the α1,α2B antagonist, prazosin, and the V2-receptorantagonist, d(CH2)5 [D-I1e2,Ile4,Ala-NH29]AVP.RESULTS: Xylazine at 2.5 mg/kg caused a significant and prolonged dose-dependent increase in urine flow rate and sodium excretion but had only short-lasting effects on blood pressure, heart rate, and glomerular filtration rate. Prazosin had no effect on the measured responses. Although plasma glucose concentration and glucose excretion rate were increased by xylazine, the magnitudes of these increases were insufficient to account for the diuresis observed. Xylazine, and 2 other α2 agonists, clonidine and oxymetazoline, increased urine flow and/or sodium excretion despite the presence of d(CH2)5 [D -Ile2,Ile4,Ala-NH29]AVP.CONCLUSIONS: Xylazine causes a diuretic and natriuretic α2A-adrenergic response in the rat that is independent of changes in glomerular filtration rate, the development of glucosuria, or AVP action on the distal nephron of the kidney.CLINICAL RELEVANCE: The adverse effects of xylazine on salt and water balance need to be considered and possibly compensated for by fluid replacement or post-surgical administration of α2-receptor antagonists.

Compression testing of cadaver specimens showed that excision of the radial head allowed proximal radial displacement. The insertion of a metallic radial head restored normal mechanics, while a silicone rubber implant did not. We reviewed 31 of 36 comminuted fractures of the radial head, 21 associated with dislocation or ulnar fracture, which had been treated by primary replacement with a Vitallium prosthesis. At a mean follow-up of 4.5 years, there was reliable restoration of stability and prevention of proximal radial migration. There had been no dislocations or prosthetic failures, but two implants had been removed for loosening. The prosthesis is recommended for use as a spacer to stabilise the elbow after severe injuries while the soft tissues heal.

Eighteen patients with marginal depressed or comminuted fractures of the head of the radius, nine of whom had an associated posterior dislocation of the elbow, had a Silastic replacement carried out shortly after injury. After an average follow-up of twenty-six months satisfactory clinical results were observed in seventeen cases; three prostheses broke. The prosthesis has been particularly effective in the group with an associated posterior dislocation of the elbow.

The calcaneal tendons of rabbits were excised and either replaced with a carbon or polyester fibre implant, or left as controls. The strength of the neotendons and their mode of failure under tension were examined at intervals up to six months after operation. Return to near normal strength took six months to develop, suggesting that patients having ligament or tendon reconstructions should not resume normal activity for several months. Carbon fibre-based neotendons showed progressive elongation which, unless avoided by a sufficient period of immobilisation, would affect the functional result.

The effects of synovectomy and excision of the radial head in 40 elbows affected by rheumatoid arthritis have been assessed. In contrast with many reports indicating minimal side-effects of this procedure, a common pattern of deterioration from what was often a satisfactory initial result has been demonstrated. A biomechanical theory of one of the factors responsible for failure has been put forward and the importance of conserving or replacing the radial head emphasised.

Carbon-fibre and polyester-fibre implants of comparable dimensions were used to replace the calcaneal tendon in 30 sheep. The neotendon produced in proximity to the polyester fibres was denser, more collagenous and more closely adherent than that in the carbon-based neotendon. Fragmentation of the carbon caused continuing cellular reaction which was associated with a poor collagen response.

The anterior cruciate ligament was replaced in rabbits, using implants of carbon or polyester filaments with known mechanical properties. The biocompatibility of the implants was assessed in detail using light microscopy, and scanning and transmission electron microscopy. Mechanical tests were made of stability, in comparison with normal joints and controls after excision of the ligament. Some carbon fibre implants broke down in vivo, allowing instability; the fragments caused chronic inflammation. Intact carbon implants did not induce the formation of neoligaments; they were covered by tissue, but there was no ingrowth. Polyester did not degrade mechanically and supported early collagenous ingrowth within the implant, even in the mid-joint space. It was concluded that there was no justification for the use of carbon fibres as anterior cruciate replacements; polyester appeared to be suitable.

Computed tomography (CT) coronary angiography is now a widely available and reliable test accessible on basic CT platforms that can exclude coronary heart disease with confidence. It is fast, cheap and, if properly carried out by trained and accredited staff in carefully selected patients, useful information can be obtained with acceptably low radiation exposure in some cases.