European Working Time Directive: implications for surgical training.

The forthcoming implementation of the European Working Time Directive (EWTD) for non-consultant hospital doctors (NCHDs) poses a number of challenges in the areas of patient care, training, service provision and quality of life for workers. Surgery, as a craft-based speciality, will face a greater impact on training of future surgeons as operating time could be lost to service provision. The EWTD acts a stimulus for reform of current working practices and re-configuration of services. It will necessitate transformation of the way in which surgeons are trained, if current standards are to be maintained.

Coracoid impingement syndrome: a treatable cause of anterior shoulder pain.

BACKGROUND: Coracoid Impingement Syndrome is a relatively uncommon but generally treatable cause of anterior shoulder pain that can be easily overlooked. It typically presents with anterior shoulder joint pain in activities involving forward flexion, adduction and internal rotation. AIMS: To assess the outcome of a cohort of patients diagnosed with Coracoid Impingement Syndrome. METHODS: Patients were investigated clinically and radiologically. They received appropriate therapeutic measures and were followed-up in an orthopaedic outpatient setting. RESULTS: Twelve patients were identified over a four-year period. All patients have made good progress. Thus far, none have needed operative intervention for symptom relief. CONCLUSION: Coracoid impingement syndrome is an uncommon cause of anterior shoulder pain but diagnosed patients can expect good symptomatic relief following referral to a dedicated shoulder unit. An increase in clinical awareness of the condition may prevent undue diagnostic delay in such cases.

Discrete pathways for arachidonic acid release from tannin versus beta-glucan-stimulated rabbit alveolar macrophages.

Previously, we observed both tannin and beta-glucan to be agonists for arachidonic acid (AA) release from rabbit alveolar macrophages. Although tannin inhibited reincorporation of exogenous AA, beta-glucan had no apparent effect, suggesting separate signal transduction pathways leading to elevated AA levels. In this study alveolar macrophages were pretreated with the tyrosine phosphatase inhibitor sodium orthovanadate then stimulated with either condensed tannin or beta-glucan. Vanadate exerted opposing effects on AA release. Furthermore, vanadate reversed the ability of tannin to inhibit reacylation. Additional studies using the phospholipase A probe bis-BODIPY-C11-PC indicated that although the known phospholipase A2 activators, calcium ionophore A23187, insoluble immune complexes, and beta-glucan, generated an increase in fluorescence consistent with phospholipase A activation, tannin had no effect. These findings suggest the increase in free AA resulting from stimulation of macrophages by either tannin or beta-glucan is produced via two different mechanisms.

Physical and biological properties of cationic triesters of phosphatidylcholine.

The properties of a new class of phospholipids, alkyl phosphocholine triesters, are described. These compounds were prepared from phosphatidylcholines through substitution of the phosphate oxygen by reaction with alkyl trifluoromethylsulfonates. Their unusual behavior is ascribed to their net positive charge and absence of intermolecular hydrogen bonding. The O-ethyl, unsaturated derivatives hydrated to generate large, unilamellar liposomes. The phase transition temperature of the saturated derivatives is very similar to that of the precursor phosphatidylcholine and quite insensitive to ionic strength. The dissociation of single molecules from bilayers is unusually facile, as revealed by the surface activity of aqueous liposome dispersions. Vesicles of cationic phospholipids fused with vesicles of anionic lipids. Liquid crystalline cationic phospholipids such as 1, 2-dioleoyl-sn-glycero-3-ethylphosphocholine triflate formed normal lipid bilayers in aqueous phases that interacted with short, linear DNA and supercoiled plasmid DNA to form a sandwich-structured complex in which bilayers were separated by strands of DNA. DNA in a 1:1 (mol) complex with cationic lipid was shielded from the aqueous phase, but was released by neutralizing the cationic charge with anionic lipid. DNA-lipid complexes transfected DNA into cells very effectively. Transfection efficiency depended upon the form of the lipid dispersion used to generate DNA-lipid complexes; in the case of the O-ethyl derivative described here, large vesicle preparations in the liquid crystalline phase were most effective.

Expression pattern of CK7, CK20, CDX-2, and villin in intestinal-type sinonasal adenocarcinoma.

BACKGROUND: Intestinal-type sinonasal adenocarcinoma (ITAC) is an uncommon neoplasm, which resembles adenocarcinoma of the gastrointestinal tract. ITAC occurs sporadically or in association with occupational exposure to hardwood dust and other agents. AIMS: To investigate the phenotype and possible pathogenetic mechanisms of primary sinonasal and nasopharyngeal adenocarcinomas by staining for cytokeratin 7 (CK7), CK20, CDX-2, and villin. METHODS: Twelve sporadic sinonasal and nasopharyngeal adenocarcinomas were stained with monoclonal antibodies to CK7, CK20, CDX-2, and villin. The ITACs were classified as papillary, colonic, solid, mixed, or mucinous types. RESULTS: The diagnosis of ITAC was confirmed in 10 cases: five were colonic type and five were papillary. One was a sinonasal papillary low grade adenocarcinoma, and one a papillary nasopharyngeal adenocarcinoma, and these tumours were CK7 positive, but CK20, CDX-2, and villin negative. All ITACs were positive for CK20, CDX-2, and villin, and six were CK7 positive. One ITAC had a focus of intestinal metaplasia away from the invasive carcinoma. CONCLUSIONS: Sinonasal ITACs have a distinctive phenotype, with all cases expressing CK20, CDX-2, and villin. Most ITACs also express CK7, although a proportion of tumours are CK7 negative. ITAC seems to be preceded by intestinal metaplasia of the respiratory mucosa, which is accompanied by a switch to an intestinal phenotype. Although ITACs are morphologically similar, differences in cytokeratin expression patterns suggest two distinct types. The expression pattern of CK7, CK20, CDX-2, and villin positive may be useful in separating these tumours from other non-ITAC adenocarcinomas of the sinonasal tract and nasopharynx.

A computed tomography evaluation of two hundred normal ankles, to ascertain what anatomical landmarks to use when compressing or placing an ankle syndesmosis screw.

Classical AO teaching recommends that a syndesmosis screw should be inserted at 25-30 degrees to the coronal plane of the ankle. Accurately judging the 25/30 degree angle can be difficult, resulting in poor operative reduction of syndesmosis injuries. The CT scans of 200 normal ankles were retrospectively examined. The centroid of the fibula and tibia in the axial plane 15mm proximal to the talar dome was calculated. A force vector between the centroid of the fibula and the tibia in the axial plane should not displace the fibula relative to the tibia when surfaces are parallel. Therefore, a line connecting the two centroids was postulated to be the ideal syndesmosis line. This line was shown to pass through the fibula within 2.5mm of the lateral cortical apex of the fibula and the anterior half of the medial malleolus in 100% of the ankles studied. The results support the concept that in the operatively reduced syndesmosis, the anterior half of the medial malleolus can be used as a reliable guide for aiming the syndesmosis drill hole, provided that the fibular entry point is at/or adjacent to the lateral fibular apex. The screw should also remain parallel to the tibial plafond in the coronal plane.

Fixation of tibial plateau fractures with synthetic bone graft versus natural bone graft: a comparison study.

PURPOSE: The goal of this study was to determine differences in fracture stability and functional outcome between synthetic bone graft and natural bone graft with internal fixation of tibia plateau metaphyseal defects. METHODS: Hydroxyapatite calcium carbonate synthetic bone graft was utilised in 14 patients (six males and eight females). Allograft/autograft were utilised in the remaining 10 patients (six males and four females). All the 24 patients had clinical, radiological and subjective functional score assessments. RESULTS: There was no significant statistical difference between the groups for post-operative articular reduction, long-term subsidence, and WOMAC scores. The degree of subsidence was not related to age or fracture severity. Maintenance of knee flexion was found to be better in the allograft/autograft group (p = 0.048) when compared between the groups. Multivariate analysis compared graft type, fracture severity, post-operative reduction, subsidence rate, range of movement and WOMAC score. The only finding was a statistical significant association with the graft type related to the 6-month range of movement figures. CONCLUSIONS: Use of autologous or allogenic bone graft allows better recovery of long-term flexion, possibly due to reduced inflammatory response compared with synthetic bone composites. However, all other parameters, such as maintenance of joint reduction and subjective outcome measures were comparable with the use of hydroxyapatite calcium carbonate bone graft. This study shows that synthetic bone graft may be a suitable alternative in fixation of unstable tibia plateau fractures, avoiding risk of disease transmission with allograft and donor site morbidity associated with autograft.

Whole body MRI in the diagnosis of chronic recurrent multifocal osteomyelitis.

Chronic recurrent multifocal osteomyelitis (CRMO) is a diagnosis of exclusion primarily in children and adolescents. As part of the essential criteria for the diagnosis of CRMO, multifocal lesions must be identified. We present the case of an 11-year-old boy with CRMO, whose diagnosis was facilitated by the use of whole body magnetic resonance imaging (WBMR), but not isotope bone scanning.

Radiological outcomes of distal radius extra-articular fragility fractures treated with extra-focal kirschner wires.

INTRODUCTION: The classical colles fracture (extra-articular, dorsally angulated distal radius fracture) in patients with osteoporotic bone is becoming increasingly more frequent. There still appears to be no clear consensus on the most appropriate surgical management of these injuries. The purpose of this study is to appraise the use of percutaneous extra-focal pinning, in the management of the classical colles fracture. METHODS: We retrospectively analysed 72 consecutive cases of colles fractures treated with inter-fragmentary k-wire fixation, in female patients over 60 years of age, in two orthopaedic centres, under the care of 12 different orthopaedic surgeons. We correlated the radiographical distal radius measurements (ulnar variance, volar tilt, and radial inclination) at the pre-operative and intra-operative stages with the final radiographical outcome. RESULT: Mean dorsal angulation was 21 degrees at time of presentation. Closed reduction significantly improved fracture position to a mean of 2.7 degrees volar angulation (p<0.05). Mean angulation at time of k-wire removal was 1.6 degrees dorsal, this was not significant in comparison to post-reduction measurements (p<0.05). Mean ulnar variance at time of presentation was 2.5mm (range 7.4 to -4.2). Reduction improved fracture displacement to a mean of 0mm, which was statistically significant (p<0.05). Mean ulnar variance at time of k-wire removal was 2.4mm (p<0.05). 56.8% of cases demonstrated radial shortening of 2mm or more. CONCLUSION: In female patients over 60 years of age, the best predictor of radial length, when k-wire fixation is to be used, is the radial length prior to fracture reduction. Thus if there is radial shortening visible in the initial radiographs as measured in terms of ulnar variance, one should consider a method of fixation other than inter-fragmentary k-wires.

Evaluation of enzyme-linked immunosorbent assay for the serodiagnosis of amebiasis.

This report describes the development and evaluation of an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to Entamoeba histolytica. Highly sensitive and reproducible results were obtained in antigen-coated plates prepared by air-drying at 37 degrees C. Comparison of the ELISA with indirect fluorescent antibody and indirect hemagglutination techniques showed that the former was slightly more sensitive than the two latter methods. The specificity was evaluated by testing specially chosen population groups. ELISA was negative in 96.4% of 693 normal adults and children and in 96.6% of 377 patients with various parasitic, bacterial, mycotic, and other clinical diseases. The assay was positive in 26% of 461 patients with suspected amebiasis and in all of 53 patients with amoebic liver abscess. The ELISA was found to be a specific, highly sensitive, and reliable procedure for detecting anti-E. histolytica antibodies in humans.

Contributions of myristoylation to calcineurin structure/function.

Calcineurin is a serine/threonine protein phosphatase composed of a catalytic subunit, calcineurin A (58 kDa), and a NH2-terminal myristoylated regulatory subunit, calcineurin B (19 kDa). In order to study the effect of myristoylation on calcineurin structure/function, a dual plasmid transfection system was used to generate myristoylated and nonmyristoylated calcineurin B. Both metabolic labeling of calcineurin B with radiolabeled myristic acid and electrospray mass spectral analysis confirmed that myristic acid was covalently and stoichiometrically linked to calcineurin B. Myristoyl and non-myristoyl calcineurin B were reconstituted with recombinant calcineurin A to form native-like heterodimers, and the properties of the two calcineurin forms were examined. Myristoylation had no effect on enzymatic activity, calcineurin-immunosuppressant/immunophilin interactions, or Ca2+ binding. Surprisingly, myristoylation also had no effect on calcineurin heterodimer association with phospholipid monolayers. Fatty acylation, however, significantly influenced the thermal stability of calcineurin, with an approximate 10 degrees C increase in t1/2 observed for myristoyl calcineurin when compared to the non-myristoyl form. Myristoylation of calcineurin B therefore appears to provide structural stability to the calcineurin heterodimer.

Determinants of calcineurin binding to model membranes.

The biochemical factors that lead to membrane targeting of the Ser/Thr protein phosphatase calcineurin were examined using model phospholipid membranes. The interaction of myristoyl- and non-myristoylcalcineurin with lipid surfaces was investigated as a function of negatively charged phospholipids, diacylglycerol, Ca2+, and calmodulin. The data indicate that calcineurin binding to phospholipid monolayers both is myristoyl-independent and is mediated by anionic phospholipids and/or diacylglycerol. Although the effect of Ca2+ on calcineurin-lipid binding is minor, calmodulin altered the binding of calcineurin to the lipid membrane in a Ca2+-dependent manner. Experiments with a constitutively active form of calcineurin that does not bind calmodulin indicated that the effect required the interaction of calcineurin with calmodulin. Our results suggest that phosphatidylserine, diaclyglycerol, and calmodulin may mediate the lipid binding properties of calcineurin in vivo.

Encapsulation of bilayer vesicles by self-assembly.

Vesicles of lipid bilayers have been investigated as drug-delivery vehicles for almost 20 years. The vesicles' interior space is separated from the surrounding solution because small molecules have only limited permeability through the bilayer. Single-walled (unilamellar) vesicles are made by a variety of non-equilibrium techniques, including mechanical disruption of lamellar phases by sonication or extrusion through filters, or chemical disruption by detergent dialysis or solvent removal. These techniques do not, however, allow the encapsulation of a specific volume, nor can they be used to encapsulate other vesicles. Here we show that molecular-recognition processes mediated by lipophilic receptors and substrates (here the biotin-streptavidin complex) can be used to produce a multicompartmental aggregate of tethered vesicles encapsulated within a large bilayer vesicle. We call these encapsulated aggregates vesosomes. Encapsulation is achieved by unrolling bilayers from cochleate cylinderss which are tethered to the aggregate by biotin-streptavidin coupling. These compartmentalized vesosomes could provide vehicles for multicomponent or multifunctional drug delivery; in particular, the encapsulating membrane could significantly modify permeation properties, or could be used to enhance the biocompatibility of the system.

Factors governing the assembly of cationic phospholipid-DNA complexes.

The interaction of DNA with a novel cationic phospholipid transfection reagent, 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine (EDOPC), was investigated by monitoring thermal effects, particle size, vesicle rupture, and lipid mixing. By isothermal titration calorimetry, the heat of interaction between large unilamellar EDOPC vesicles and plasmid DNA was endothermic at both physiological and low ionic strength, although the heat absorbed was slightly larger at the higher ionic strength. The energetic driving force for DNA-EDOPC association is thus an increase in entropy, presumably due to release of counterions and water. The estimated minimum entropy gain per released counterion was 1.4 cal/mole- degrees K (about 0.7 kT), consistent with previous theoretical predictions. All experimental approaches revealed significant differences in the DNA-lipid particle, depending upon whether complexes were formed by the addition of DNA to lipid or vice versa. When EDOPC vesicles were titrated with DNA at physiological ionic strength, particle size increased, vesicles ruptured, and membrane lipids became mixed as the amount of DNA was added up to a 1.6:1 (+:-) charge ratio. This charge ratio also corresponded to the calorimetric end point. In contrast, when lipid was added to DNA, vesicles remained separate and intact until a charge ratio of 1:1 (+:-) was exceeded. Under such conditions, the calorimetric end point was 3:1 (+:-). Thus it is clear that fundamental differences in DNA-cationic lipid complexes exist, depending upon their mode of formation. A model is proposed to explain the major differences between these two situations. Significant effects of ionic strength were observed; these are rationalized in terms of the model. The implications of the analysis are that considerable control can be exerted over the structure of the complex by exploiting vectorial preparation methods and manipulating ionic strength.