Oestrous synchronization, ovarian superovulation and intraspecific transfers from a closed breeding colony of inbred SLA miniature pigs

The inbred SLA miniature pig is a unique animal model developed for organ transplantation studies and pre-clinical experimental purposes. Reported oestrous synchronization and superovulation treatments were examined in two SLA haplotypes (AA and DD) to allow collection of embryos for both practical embryo transfer and experimental technologies from a closed breeding colony. Pre-puberal miniature pigs were poor responders to oestrous synchronization treatments, while post-puberal sows were equivalent to commercial sows. Following superovulation, the ovulation number (corpora .hemorrhagica) was higher (p < 0.05) in the cycling sows when compared with non-cycling sows. Ovulations were equivalent to commercial pre-puberal gilts and non-cycling sows (p > 0.05). No difference in ovulation number between haplotypes was observed, which differs from the previous report (DD>AA). Collection of zygotes for pronuclear injection was the highest in the non-cycling post-puberal miniature pig group (p < 0.05), although significantly lower when compared with the commercial pig treatment groups (p < 0.05). The incidence of cystic endometrial hyperplasia in our colony was equivalent to rates observed in commercial pigs. Pronuclear visualization following centrifugation was the highest in the non-cycling miniature sow group and approximates to about 25% of ovulations and about half the rate observed in the commercial pigs (50%). Miniature pig embryos transferred between SLA haplotypes and transfer of DD embryos to commercial pigs resulted in live births at a higher efficiency than previously reported. This study demonstrates the feasibility of undertaking assisted reproductive technologies in a closed breeding colony of inbred SLA miniature pigs without compromise to the breeding programmes.

Novel polymeric coatings with the potential to control in-stent restenosis--an in vitro study

Restenosis following percutaneous coronary intervention (PCI) is a considerable problem in long-term performance of cardiovascular stents, with a functional endothelial cell monolayer being important in its prevention. This study evaluates the influence of polymer coatings on human aortic endothelial cells (HAEC) and coronary artery smooth muscle cells (HCASMC) in vitro, in terms of morphology, cell number, and phenotype. It was demonstrated that the polymer coatings can be tailored to enhance adhesion and growth of HAECs whilst suppressing that of HCASMCs. It is concluded that one of the polymer coatings (BTL 01015) shows potential as a stent coating to enhance re-endothelialization.

Studies of whole blood coagulation by oscillatory shear, thromboelastography and free oscillation rheometry

We report studies of the coagulation of samples of whole human blood by oscillatory shear techniques, including Fourier Transform Mechanical Spectroscopy (FTMS). These techniques are used herein to identify the Gel Point of coagulating blood in terms of the Chambon-Winter Gel Point criterion which provides a rheometrical basis for detecting the establishment of an incipient clot. A comparison of the results of FTMS with those obtained from measurements involving a Thromboelastograph (TEG) and a Free Oscillation Rheometer (FOR) indicate that the latter techniques are not capable of detecting the incipient clot, whose establishment occurs several minutes prior to TEG or FOR-based assessments of clot formation time. The results of the present study suggest that FTMS is a useful tool in blood clotting research, being capable of providing a global coagulation profile in addition to detecting the instant of incipient clot formation.

Rheometry and associated techniques for blood coagulation studies

This review considers various rheometrical approaches that have been adopted to study blood coagulation, with special reference to the rheological assessment of clotting time and studies of the evolution of viscoelasticity during the course of fibrin polymerization and cross-linking. The significance of the Gel Point in blood coagulation studies is discussed as a common feature of many of these studies in that they attempt to detect a liquid-to-solid transition during coagulation. Coagulation studies based on various forms of complex shear modulus measurements are considered, the latter being based principally on controlled stress and controlled strain rheometers. Also considered are the long established technique of thromboelastography and several emerging techniques such as wave propagation measurements, free oscillation rheometry, quartz crystal microbalance measurements and surface plasmon resonance.

Neurosarcoidosis presenting as acute infarction on diffusion-weighted MR imaging: summary of radiologic findings

A 36-year-old woman presented with acute-onset right lower extremity paresthesias, dysarthria, right facial droop, and right hemiparesis. CT and MR imaging of the brain revealed extensive white matter disease and left basal ganglia infarction with dural and leptomeningeal enhancement. Differential considerations included vasculitis, granulomatous disease, and neoplasm. Chest, abdomen, and pelvis CTs were normal. Right temporal lobe biopsy revealed noncaseating granulomatous inflammation consistent with neurosarcoidosis.

The effect of silica nanoparticulate coatings on serum protein adsorption and cellular response

Serum protein adsorption on colloidal silica surfaces was investigated using a quartz crystal microbalance with dissipation (QCM-D) monitoring. The amount of serum proteins adsorbed on colloidal silica-coated surfaces was not significantly different from the control silica surfaces, with the exception of 21nm colloidal silica which experienced significantly less (P<0.05) fibrinogen adsorption compared with control silica. The adhesion and proliferation of human endothelial cells (C11STH) on nano-scale colloidal silica surfaces were significantly reduced compared with control silica surfaces, suggesting that the conformation of adsorbed proteins on the colloidal silica surfaces plays a role in modulating the amount of cell binding. Fibronectin is one of the main extracellular matrix proteins involved in endothelial cell attachment to biomaterial surfaces. There was reduced binding of a monoclonal anti-fibronectin antibody, that reacted specifically with the cell-binding fragment, to fibronectin-coated colloidal silica surfaces compared with control silica surfaces. This suggests that the fibronectin adsorbed on the colloidal silica-coated surfaces was conformationally changed compared with control silica reducing the availability of the cell-binding domain of fibronectin.

Rheometrical and computational studies of blood viscoelasticity during coagulation

The rheological behaviour of coagulating human blood has been measured using multiple strain wave frequencies. The results indicate that coagulating blood, prior to the point of incipient clot formation, can be modelled by a modified form of the Gross-Marvin 'ladder' model, and the benefits of such modeling for blood coagulation are discussed.

Polyurethanes as potential substrates for sub-retinal retinal pigment epithelial cell transplantation

Transplantation of cultured retinal pigment epithelial (RPE) cells under the failing macular is a potential treatment for age related macular degeneration. An important step in the development of this procedure is the identification of a suitable membrane on which to grow and transplant the cells. This paper evaluates the potential of using polyurethanes in this application since they possess several of the required properties, such as, flexibility, robustness, biostability and good biocompatiblilty although their hydrophobicity can limit cell adhesion. Three commercially available polyether urethanes (Pellethane, Tecoflex and Zytar) were evaluated in terms of their wettability using dynamic contact angle analysis and their ability to support a monolayer of functioning RPE cells (ARPE-19) . Furthermore Pellethane and Tecoflex were treated with a simple air plasma treatment and analysed as above. In the "as received condition" only a few RPE cells attached to the Pellethane and Tecoflex and remained clumped. RPE cells grew to confluence on the Zytar substrate by 7 days without further surface modification. Air gas plasma treatment of both Pellethane and Tecoflex increased the wettability of the surfaces and this resulted in the growth of a monolayer of well-spread RPE cells on both materials. Morphologically these cells grew with a normal 'cobblestone' phenotype. These results demonstrate the potential of these polyurethanes for this application.

Congenital pulmonary lymphangiectasia presenting as nonimmune fetal hydrops and severe respiratory distress at birth: not uniformly fatal

Pulmonary lymphangiectasia is a rare cause of respiratory distress in the newborn associated with a very poor outcome. We describe three premature newborns presenting at birth with nonimmune hydrops, bilateral chylothorax, and severe respiratory distress in the immediate newborn period secondary to pulmonary lymphangiectasia. We review the similarities of these cases and discuss their antenatal and neonatal course. One patient survived and is thriving at 9 months of age. With continuing advances in antenatal and neonatal care, an improved outcome may be possible in what was previously described as a uniformly fatal condition.

Chronic compartment syndrome, an important cause of work-related upper limb disorder

OBJECTIVES

Work-related upper limb disorders (WRULD) are common and disabling complaints in industry, but a tissue diagnosis can be difficult where the pain is diffuse and variable, and this prevents effective treatment. Diffuse arm pain is frequently found in those doing rapid or strenuous repetitive work, such as factory assembly workers or keyboard operators. Similar symptoms occur in the legs in athletes, where chronic compartment syndrome (CCS) is a recognized entity, so we investigated the possibility that this might also be caused by prolonged repetitive work.

METHODS

Patients were selected if they were unable to continue with work because of chronic forearm pain. They were divided into three groups: 42 patients with symptoms consistent with CCS as defined in the text, 15 volunteers and patients with other arm complaints, and 10 asymptomatic arms of patients with unilateral CCS. We measured the pressure inside the extensor muscle compartment of the forearm at rest and after a 2 min repetitive gripping exercise using an electronic pressure-sensitive probe.

RESULTS

The results show that CCS is a common and disabling forearm complaint associated with prolonged repetitive work. Fifteen patients have now had decompressive surgery on the extensor muscle compartment with good relief of symptoms.

CONCLUSION

CCS is responsible for chronic peripheral neurological dysfunction in addition to muscle pain, and awareness of this diagnosis allows early identification and treatment of a currently unrecognized disorder with potential resolution of a long-lasting arm disability.

Stability of plasma-treated silicone rubber and its influence on the interfacial aspects of blood compatibility

Medical-grade polydimethylsiloxane elastomer was subjected to low-powered plasma treatment in the presence of four different gases: O(2), Ar, N(2) and NH(3). Changes to the surface chemistry immediately after processing and the stability of the treatments following ageing in phosphate buffered saline or air for up to 1 month were investigated using X-ray photoelectron spectroscopy and dynamic contact angle analysis. Changes in surface morphology were assessed using optical microscopy and atomic force microscopy. All treatments resulted in an increase in wettability, attributed to major changes in chemistry combined with modest etching. Furthermore, the primary site of attack of the plasma species appeared to be dependent upon the feed gas implemented. The two main chemical changes observed after ageing were due to reactions with the storage media and relaxation processes resulting in further changes in wettability. The influence of the surface modifications on the blood compatibility of the materials was investigated by assessing contact phase activation using a partial thromboplastin time assay. It was demonstrated that the O(2) and Ar plasma treatments reduced the performance of the silicone but the N(2) and NH(3) treatments had a significantly beneficial effect on the activation of the coagulation cascade.

Long-term local effects of carbon fibre in the knee

A radiological and histological analysis of five knee joints after a minimum of 15 years following the implanting of carbon fibre, which had been used as a treatment for knee instability, was undertaken. All patients underwent total knee replacement for secondary osteoarthritis. Histological analysis demonstrated a variable amount of macroscopically visible carbon particles in the synovium, hyaline cartilage and menisci. At microscopy these particles were found in association with fibrous tissue adjacent to bone with no acute inflammatory changes. No intact carbon fibre ligament was noted within the joint, small portions of the old ligament were covered with a thin fibrous layer but there was no evidence of any structure resembling neo-ligament. Extra articularly the carbon fibre was covered with a thick fibrous sheath with no active inflammation changes inflammation. In the bone tunnels, the carbon fibre-bone interface showed an apposition of the bone to the carbon fibre without any interposing fibrous sheath. Carbon fibre bonds directly with the bone without fibrous interposition.

The effect of silica nanoparticulate coatings on cellular response

The current techniques used to create patterned materials at the nanometer scale such as electron beam lithography are restricted to patterning small areas, which can be expensive and time consuming. A simple, cost-effective approach has been developed to create a reproducible surface topography to influence the cellular response. In this study, the cellular response of murine fibroblasts to 7, 14 and 21 nm colloidal silica particles were investigated over one, three and seven days and up to seven weeks. The surface topography and wettability of the surfaces were also studied. The results confirmed that silica particles create a nanoscale topography, which initiates a distinctive cellular response affecting the morphology, adhesion and proliferation of the fibroblasts. The effect was evident up to seven weeks with no adverse effects on cell viability.

Surface modification of a segmented polyetherurethane using a low-powered gas plasma and its influence on the activation of the coagulation system

A medical grade segmented polyetherurethane (PEU) was treated with a low-powered gas plasma using O(2), Ar, N(2) and NH(3) as the treatment gases. Changes in the surface functional group chemistry were studied using X-ray photoelectron spectroscopy. The wettability of the surfaces was examined using dynamic contact angle measurements and the surface morphology was evaluated using atomic force microscopy. The influence of the surface modification to the polyurethane on the blood response to the polyetherurethane was investigated by measuring changes in the activation of the contact phase activation of the intrinsic coagulation cascade. The data demonstrate that the plasma treatment process caused surface modifications to the PEU that in all cases increased the polar nature of the surfaces. O(2) and Ar plasmas resulted in the incorporation of oxygen-containing groups that remained present following storage in an aqueous environment. N(2) and NH(3) plasmas resulted in the incorporation of nitrogen-containing groups but these were replaced with oxygen-containing groups following storage in the aqueous environment. In all plasma treatments there was a lowering of contact phase activation compared to the untreated surface, the N(2) and NH(3) treatments dramatically so.

Diffusion thermopower of a two-dimensional hole gas in SiGe in a quantum Hall insulating state

Both the temperature dependence of resistivity and thermopower of a two-dimensional hole gas in SiGe show a reentrant metal-insulator transition at filling factor nu=1.5, but with strikingly different behavior of the two coefficients. As the temperature is decreased in the insulating state, the resistivity diverges exponentially while the thermopower decreases rapidly, suggesting that the insulating state is due to the presence of a mobility edge rather than a gap at the Fermi energy.

Expression of leukocyte-endothelial cell adhesion molecules on monocyte adhesion to human endothelial cells on plasma treated PET and PTFE in vitro

We used a coculture model to evaluate the inflammatory potential of ammonia gas plasma modified PET and PTFE by flow cytometry and immunohistochemistry. In these studies, human endothelial cells from umbilical cord (HUVEC) and promonocytic U937 cells were used. HUVECs grown on polystyrene tissue culture coverslips and HUVECs stimulated with tumour necrosis factor (TNF-alpha) were used as controls. U937 adhesion to endothelium on each surface was evaluated at day 1 and day 7. To further investigate the role of leukocyte-endothelial cell adhesion molecules (CAMs) in cell-to-cell interaction on material surfaces, the expression of the leukocyte-endothelial CAMs: ICAM-1, VCAM-1, PECAM-1, and E-selectin on HUVECs were evaluated after U937 cell adhesion. The results demonstrated that plasma treated PET (T-PET) and treated PTFE (T-PTFE) did not increase U937 cell adhesion compared to the negative control. Maximal adhesion of U937 cells to HUVEC was observed on TNF-alpha stimulated endothelium with significant differences between day 1 and day 7, which is consistent with our prior observation that T-PET and T-PTFE did not cause HUVECs to increase the expression of adhesion molecules. After U937 cell adhesion, the expression of ICAM-1 and VCAM-1 of HUVECs were not different on T-PET and T-PTFE compared with the negative control. However, the expression of E-selectin was reduced on day 1, but not on day 7. The effects of plasma treated PET and PTFE on HUVEC adhesion and proliferation were also studied. On day 1 there were slight increases in the growth of HUVECs on both of T-PET and T-PTFE but this was not statistically significant. On day 7, the cell number increased significantly on the surfaces compared to the negative control. The results demonstrate that the plasma treatment of PET and PTFE with ammonia improves the adhesion and growth of endothelial cells and these surfaces do not exhibit a direct inflammatory effect in terms of monocyte adhesion and expression of leukocyte-endothelial CAMs. The monocyte adhesion to endothelial cells on surfaces can be used as a tool for the evaluation of material surface modification and further to study the mechanisms of cell-to-cell interactions in response to surfaces.

Common injuries of the foot and ankle

This article is aimed at accident and emergency and orthopaedic senior house officers. It emphasizes key points of the safe initial management of common foot and ankle injuries.