Albumin is an Independent Predictor of up to 9-Year Mortality for Intracapsular Femoral Neck Fractures Aiding in Decision-Making for Total Hip Arthroplasty or Hemiarthroplasty

BACKGROUND

Intracapsular femoral neck fractures in the geriatric population are usually treated with hemiarthroplasty or total hip arthroplasty. The patients' medium-term to long-term mortality is a consideration to help decide which procedure to perform. The aim of this study is to examine whether easily identifiable serum investigations and patient identifiable factors on admission are associated with medium-term and long-term mortality.

METHODS

A consecutive series of 331 patients who sustained intracapsular femoral neck fractures and were over the age of 55 years were identified and retrospectively reviewed. American Society of Anesthesiologists (ASA) grade, cognitive function, gender, age, mobility status, and admission serum investigations were considered.

RESULTS

Low albumin levels, advanced age, men, and a combination of high ASA with lower mobility status were independent predictors of mean 5-year mortality. Similarly, low albumin levels and a combination of high ASA with lower mobility status were found to be independent predictors of longer term mortality (7-9 years). The optimal albumin cut-off to identify patient survival was >42 g/L with an area under the curve of 0.71.

CONCLUSION

We suggest that serum albumin on admission can be utilized as a factor to identify patients who are likely to survive at up to 9-year mean follow-up, to guide decision for total hip arthroplasty over hemiarthroplasty.

Filamentation and focusing of electron beams due to interactions with plasma waves

Results of numerical modeling of the interaction of an electron beam propagating across relativistic plasma waves indicate that electron beam filamentation and focusing may occur under certain conditions. The model is based on solving the relativistic equation of motion in three dimensions for the individual electrons in a tenuous Gaussian beam, as they pass through a relativistic plasma wave. Several electron beam and plasma wave parameters were varied, and the results are summarized. One of the results is that the spacing of the electron beam filaments correlates with the wavelength of the plasma wave. The electron beam filaments appear as vertical slabs after the beam exits the plasma waves. The electron beam also compresses to a focus after it exits the plasma, and the focal distance depends on several parameters including the electron beam energy and phase velocity of the relativistic plasma wave. It is suggested that these focusing and filamentation phenomena may be the basis for diagnostics schemes for laser plasma interactions. The parameters used in the model were electron beam energies in the 5-50 keV range and plasma wave properties typical for the beat-wave produced by CO₂ lasers, which correspond to the facilities available in our laboratory. The limitations of these results to lower energy density beam and plasma regimes and to higher energy density regimes will be discussed.

The innominate tubercle of the femur is a consistent surgical landmark and shows no variation between sex and side: An osteological study

INTRODUCTION

During direct anterior approach hip arthroplasty, the innominate tubercle (IT) of the femur is used as a reference point for femoral neck osteotomy. A recent study found that IT dimensions are unaffected by femoral length, neck-shaft angle, and neck length. This study investigated the position of the tubercle relative to femoral side, sex and femoral neck dimensions.

MATERIALS AND METHODS

One hundred and ninety femora (95 pairs, complete with biographical data) from St. Bride's Church, London, were photographed with the apex of the tubercle marked. Using imaging software, axes were superimposed onto the image, allowing the X and Y co-ordinates of the tubercle apex to be derived. Statistical analysis was carried out.

RESULTS

The position of the tubercle did not vary significantly and did not correlate with femoral side (p > .05). P values for variation of the X and Y coordinates were 0.351 and 0.996 in left and right femora, respectively. The tubercle position did not vary significantly with sex (p > .05). p Values for variation of the X and Y coordinates were 0.254 and 0.634 in males and females, respectively. There was little variation between tubercle position and femoral neck dimensions: correlation coefficient -0.20 (x coordinate) and -0.12 (y coordinate).

CONCLUSIONS

The data showed that the position of the IT did not vary significantly with either sex or side and that, therefore, the tubercle can be considered a reliable surgical landmark during arthroplasty surgery.

Does Medial Overhang of the Greater Trochanter Influence Femoral Stem Position During Cemented Hip Arthroplasty? A Retrospective Radiological Review

Purpose We investigate the effect that variation in the anatomy of the greater trochanter (GT), in particular the medial overhang, can have on femoral stem alignment in total hip arthroplasty (THA). Methods Pre- and post-operative anteroposterior pelvic radiographs of 576 consecutive patients undergoing THA were retrospectively analysed. Medial overhang of the GT relative to the lateral femur diaphysis was measured. The femoral morphology was classified according to Dorr classification. The alignment of the femoral stem axes on post-operative radiographs was recorded. Results Following exclusions, 500 THAs performed by six surgeons all using the same cemented polish tapered stems were analysed: 320 THAs were performed via the posterior-lateral approach and 180 via the direct-lateral approach. Mean stem varus was 0.53° (range: -7 to 7°). Mean medial overhang was 21 mm (range: 8-43 mm). An overhang of <20 mm had a mean varus of -0.1°, an overhang of 20-30 mm had a mean varus of 0.8° and an overhang of >30 mm had a mean varus of 2.33°. Those with an overhang of <20 mm had a 2% chance of significant varus (≥4°), increasing to 9.5% for 20-30 mm and 44.4% for >30 mm. One-way analysis of variance comparison of these groups returned a p-value of <0.0001. Dorr type A femora had a mean varus of 0.52°, Dorr B had a mean varus of 0.54° and Dorr C had a mean varus of 0.46°. The posterior-lateral approach had a mean varus of 1.05° (range: -7 to 7°) compared to -0.40° (range: -5 to 5°) for direct-lateral approach. The t-test comparing approach was p < 0.0001. Discussion The extent of medial overhang of the GT can adversely affect the final stem position in THA, resulting in a statistically significant increase in mean stem varus. There is a linear relationship between stem position and GT overhang, with an increased chance of significant varus malposition (44.4% with >30 mm of overhang). Conclusions Scrutiny of pre-operative radiographs to determine high-risk patients is important, and we propose a classification system of GT anatomy to aid assessment.

CRISPR-Cas9-mediated labelling of the C-terminus of human laminin β1 leads to secretion inhibition

Objectives

The laminins (LM) are a family of basement membranes glycoproteins with essential roles in supporting epithelia, endothelia, nerves and muscle adhesion, and in regulating a range of processes including cell migration, stem cell maintenance and differentiation. However, surprisingly little is known about the mechanisms of turnover and remodelling of LM networks due to lack of appropriate tools to study these processes at the necessary resolution. Recently, the nematode C. elegans ortholog of human the LMβ1 chain was labelled at the C-terminus with the photoconvertible fluorophore Dendra2. Here we used genome editing to establish a similar system in a mammalian cell line as proof of concept for future mammalian models.

Results

CRISPR-Cas9 was used to introduce the Dendra2 sequence at the C-terminus of LMβ1 in the human lung adenocarcinoma cell line A549. Despite expression of the tagged protein within cells, no detectable LMβ1-Dendra2 protein was deposited to the extracellular matrices or conditioned media of edited cells. Moreover, the edited cells displayed reduced proliferation rates. Together, these data suggest that, in humans, addition of C-terminal Dendra2 tag to LMβ1 inhibits LM secretion, and is not a viable approach for use in animal models.

Proposed Scheme to Generate Bright Entangled Photon Pairs by Application of a Quadrupole Field to a Single Quantum Dot

Entangled photon sources are crucial for quantum optics, quantum sensing, and quantum communication. Semiconductor quantum dots generate on-demand entangled photon pairs via the biexciton-exciton cascade. However, the pair of photons are emitted isotropically in all directions, thus limiting the collection efficiency to a fraction of a percent. Moreover, strain and structural asymmetry in quantum dots lift the degeneracy of the intermediate exciton states in the cascade, thus degrading the measured entanglement fidelity. Here, we propose an approach for generating a pair of entangled photons from a semiconductor quantum dot by application of a quadrupole electrostatic potential. We show that the quadrupole electric field corrects for the spatial asymmetry of the excitonic wave function for any quantum dot dipole orientation and fully erases the fine-structure splitting without compromising the spatial overlap between electrons and holes. Our approach is compatible with nanophotonic structures such as microcavities and nanowires, thus paving the way towards a deterministic source of entangled photons with high fidelity and collection efficiency.

A gellan-based fluid gel carrier to enhance topical spray delivery

Autologous cell transplantation was introduced to clinical practice nearly four decades ago to enhance burn wound re-epithelialisation. Autologous cultured or uncultured cells are often delivered to the surface in saline-like suspensions. This delivery method is limited because droplets of the sprayed suspension form upon deposition and run across the wound bed, leading to uneven coverage and cell loss. One way to circumvent this problem would be to use a gel-based material to enhance surface retention. Fibrin systems have been explored as co-delivery system with keratinocytes or as adjunct to 'seal' the cells following spray delivery, but the high costs and need for autologous blood has impeded its widespread use. Aside from fibrin gel, which can exhibit variable properties, it has not been possible to develop a gel-based carrier that solidifies on the skin surface. This is because it is challenging to develop a material that is sprayable but gels on contact with the skin surface. The manuscript reports the use of an engineered carrier device to deliver cells via spraying, to enhance retention upon a wound. The device involves shear-structuring of a gelling biopolymer, gellan, during the gelation process; forming a yield-stress fluid with shear-sensitive behaviours, known as a fluid gel. In this study, a formulation of gellan gum fluid gels are reported, formed with from 0.75 or 0.9% (w/v) polymer and varying the salt concentrations. The rheological properties and the propensity of the material to wet a surface were determined for polymer modified and non-polymer modified cell suspensions. The gellan fluid gels had a significantly higher viscosity and contact angle when compared to the non-polymer carrier. Viability of cells was not impeded by encapsulation in the gellan fluid gel or spraying. The shear thinning property of the material enabled it to be applied using an airbrush and spray angle, distance and air pressure were optimised for coverage and viability. STATEMENT OF SIGNIFICANCE: Spray delivery of skin cells has successfully translated to clinical practice. However, it has not yet been widely accepted due to limited retention and disputable cell viability in the wound. Here, we report a method for delivering cells onto wound surfaces using a gellan-based shear-thinning gel system. The viscoelastic properties allow the material to liquefy upon spraying and restructure rapidly on the surface. Our results demonstrate reduced run-off from the surface compared to currently used low-viscosity cell carriers. Moreover, encapsulated cells remain viable throughout the process. Although this paper studies the encapsulation of one cell type, a similar approach could potentially be adopted for other cell types. Our data supports further studies to confirm these results in in vivo models.

Quantitation of class IA PI3Ks in mice reveals p110-free-p85s and isoform-selective subunit associations and recruitment to receptors

Class IA PI3Ks have many roles in health and disease. The rules that govern intersubunit and receptor associations, however, remain unclear. We engineered mouse lines in which individual endogenous class IA PI3K subunits were C-terminally tagged with 17aa that could be biotinylated in vivo. Using these tools we quantified PI3K subunits in streptavidin or PDGFR pull-downs and cell lysates. This revealed that p85α and β bound equivalently to p110α or p110β but p85α bound preferentially to p110δ. p85s were found in molar-excess over p110s in a number of contexts including MEFs (p85β, 20%) and liver (p85α, 30%). In serum-starved MEFs, p110-free-p85s were preferentially, compared with heterodimeric p85s, bound to PDGFRs, consistent with in vitro assays that demonstrated they bound PDGFR-based tyrosine-phosphorylated peptides with higher affinity and co-operativity; suggesting they may act to tune a PI3K activation threshold. p110α-heterodimers were recruited 5-6× more efficiently than p110β-heterodimers to activated PDGFRs in MEFs or to PDGFR-based tyrosine-phosphorylated peptides in MEF-lysates. This suggests that PI3Kα has a higher affinity for relevant tyrosine-phosphorylated motifs than PI3Kβ. Nevertheless, PI3Kβ contributes substantially to acute PDGF-stimulation of PIP3 and PKB in MEFs because it is synergistically, and possibly sequentially, activated by receptor-recruitment and small GTPases (Rac/CDC42) via its RBD, whereas parallel activation of PI3Kα is independent of its RBD. These results begin to provide molecular clarity to the rules of engagement between class IA PI3K subunits in vivo and past work describing "excess p85," p85α as a tumor suppressor, and differential receptor activation of PI3Kα and PI3Kβ.

Total knee arthroplasty in patients with prior adjacent multi-organism osteomyelitis

Joint degeneration may make a total knee replacement a requirement for pain relief and function, however the presence of adjacent osteomyelitis makes management extremely challenging. We describe a series of four patients with a mean age of 50 with multi-organism osteomyelitis who underwent single-stage total knee replacements at an average of 63 months following eradication. Three patients did well but had complications associated with poor skin and soft tissues, and abnormal bone anatomy. One patient developed an infection and following a re-revision had an arthrodesis. The final mean Knee Society Score and Oxford Knee Score was 62 (54-66) and 34 (29-38) respectively. We have highlighted that these are a difficult cohort of patients to manage and their care is optimised through a multi-disciplinary approach by a high volume surgeon.

Annexin-enriched osteoblast-derived vesicles act as an extracellular site of mineral nucleation within developing stem cell cultures

The application of extracellular vesicles (EVs) as natural delivery vehicles capable of enhancing tissue regeneration could represent an exciting new phase in medicine. We sought to define the capacity of EVs derived from mineralising osteoblasts (MO-EVs) to induce mineralisation in mesenchymal stem cell (MSC) cultures and delineate the underlying biochemical mechanisms involved. Strikingly, we show that the addition of MO-EVs to MSC cultures significantly (P < 0.05) enhanced the expression of alkaline phosphatase, as well as the rate and volume of mineralisation beyond the current gold-standard, BMP-2. Intriguingly, these effects were only observed in the presence of an exogenous phosphate source. EVs derived from non-mineralising osteoblasts (NMO-EVs) were not found to enhance mineralisation beyond the control. Comparative label-free LC-MS/MS profiling of EVs indicated that enhanced mineralisation could be attributed to the delivery of bridging collagens, primarily associated with osteoblast communication, and other non-collagenous proteins to the developing extracellular matrix. In particular, EV-associated annexin calcium channelling proteins, which form a nucleational core with the phospholipid-rich membrane and support the formation of a pre-apatitic mineral phase, which was identified using infrared spectroscopy. These findings support the role of EVs as early sites of mineral nucleation and demonstrate their value for promoting hard tissue regeneration.

Genomic modelling of the ESR1 Y537S mutation for evaluating function and new therapeutic approaches for metastatic breast cancer

Drugs that inhibit estrogen receptor-α (ER) activity have been highly successful in treating and reducing breast cancer progression in ER-positive disease. However, resistance to these therapies presents a major clinical problem. Recent genetic studies have shown that mutations in the ER gene are found in >20% of tumours that progress on endocrine therapies. Remarkably, the great majority of these mutations localize to just a few amino acids within or near the critical helix 12 region of the ER hormone binding domain, where they are likely to be single allele mutations. Understanding how these mutations impact on ER function is a prerequisite for identifying methods to treat breast cancer patients featuring such mutations. Towards this end, we used CRISPR-Cas9 genome editing to make a single allele knock-in of the most commonly mutated amino acid residue, tyrosine 537, in the estrogen-responsive MCF7 breast cancer cell line. Genomic analyses using RNA-seq and ER ChIP-seq demonstrated that the Y537S mutation promotes constitutive ER activity globally, resulting in estrogen-independent growth. MCF7-Y537S cells were resistant to the anti-estrogen tamoxifen and fulvestrant. Further, we show that the basal transcription factor TFIIH is constitutively recruited by ER-Y537S, resulting in ligand-independent phosphorylation of Serine 118 (Ser118) by the TFIIH kinase, cyclin-dependent kinase (CDK)7. The CDK7 inhibitor, THZ1 prevented Ser118 phosphorylation and inhibited growth of MCF7-Y537S cells. These studies confirm the functional importance of ER mutations in endocrine resistance, demonstrate the utility of knock-in mutational models for investigating alternative therapeutic approaches and highlight CDK7 inhibition as a potential therapy for endocrine-resistant breast cancer mediated by ER mutations.

Acetic Acid as Part of a Debridement Protocol During Revision Total Knee Arthroplasty

BACKGROUND

Thorough debridement is mandatory in revision for infected total knee arthroplasties (TKA). We investigated a novel adjuvant chemical debridement strategy using acetic acid (AA) that seeks to create a hostile environment for microorganisms. We report the first orthopedic in vivo series using an AA soak in infected TKAs. We also investigated the in vitro efficacy of AA against bacteria isolated from these knees.

METHODS

Twenty-three patients with infected TKA were treated with a standard debridement protocol and chemical debridement with a 20-minute AA soak. In parallel, bacteria from infected TKAs were cultured for in vitro susceptibility testing with AA solutions of different concentrations to understand its potential mechanism of action.

RESULTS

Intraoperatively, there were no physiological responses during the AA soak or on release of the tourniquet. Postoperatively, there was no increase in analgesic requirements or wound or soft-tissue complications. Clinical follow-up continued for 24 months to monitor recurrent infection. In vitro, zones of inhibition were formed on less than 40% of the organisms, demonstrating that AA was not directly bactericidal against the majority of the isolates. However, when cultured in a bacterial suspension, AA completely inhibited the growth of the isolates at concentrations as low as 0.19% vol/vol.

CONCLUSION

This study has shown that the use of 3% AA soak, as part of a debridement protocol is safe in patients. While the exact mechanism of action is yet to be determined, AA concentrations as low as 0.19% vol/vol in vitro are sufficient to completely inhibit bacterial growth.

Comparison of fruit and vegetable intakes during weight loss in males and females

BACKGROUND/OBJECTIVES

Globally, fruit and vegetable intakes are well below recommendations despite ample evidence to link insufficient intake with increased risk of overweight and obesity. Intakes of fruits and vegetables in the general population differ between males and females, and although there is growing evidence of intakes in men and women during weight loss, evidence that directly compares intakes in men and women during weight loss is lacking. This study aimed to identify any differences between males and females in fruit and vegetable intakes and plasma carotenoid concentrations during weight loss, and determine whether there is a relationship between any changes in fruit and vegetable intakes and weight change in both males and females.

SUBJECTS/METHODS

Men and women (n=100; body mass index 25-40 kg/m(2)) aged 18-60 years were selected for the study. Dietary intake of fruits and vegetables was assessed using the Australian Eating Survey and fasting blood was collected to assess plasma carotenoids, which were determined by high-performance liquid chromatography.

RESULTS

There was little change in fruit or vegetable intakes during weight loss, although men tended to increase fruit intakes. Changes in intakes were influenced by baseline intakes, with males and females with the highest intakes at baseline reducing intakes. Males had better correlations between fruit and vegetable intakes and plasma carotenoid concentrations than females, and fruit and vegetable intakes during weight loss appear to predict weight loss for males but not females.

CONCLUSIONS

Fruit and vegetable intake during weight loss does not appear to differ largely between males and females.

Effectiveness of weight loss interventions--is there a difference between men and women: a systematic review

Effective strategies are required to reduce the prevalence of overweight and obesity; however, the effectiveness of current weight loss programmes is variable. One contributing factor may be the difference in weight loss success between men and women. A systematic review was conducted to determine whether the effectiveness of weight loss interventions differs between men and women. Randomized controlled trials published up until March 2014 were included. Effect sizes (Hedges' g) were used to examine the difference in weight outcomes between men and women. A total of 58 studies met the eligibility criteria with 49 studies of higher quality included in the final data synthesis. Eleven studies that directly compared weight loss in men and women reported a significant sex difference. Ten of these reported that men lost more weight than women; however, women also lost a significant amount of weight. Analysis of effect sizes found small differences in weight loss favouring men for both diet (g = 0.489) and diet plus exercise (g = 0.240) interventions. There is little evidence from this review to indicate that men and women should adopt different weight loss strategies. Current evidence supports moderate energy restriction in combination with exercise for weight loss in both men and women.

StayFuse for proximal interphalangeal joint fusion

BACKGROUND

Proximal interphalangeal (PIP) joint fusion is a commonly performed procedure for lesser-toe deformities. There are various techniques described to accomplish it. We report the results of PIP joint fusion carried out with an intramedullary fusion device in 150 consecutive toes. The aim of our study was to evaluate the outcomes of PIP joint fusion with this technique.

METHOD

A total of 150 toes in 140 consecutive patients who underwent PIP joint fusions of the lesser toes with a StayFuse implant were included in our study. The mean age of the patients was 69.5 years, and the mean follow-up was 18 months. Clinical, radiologic, and subjective evaluations as well as preoperative and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) scores were carried out.

RESULTS

Of the PIP joints, 95.3% were clinically asymptomatic, but the radiologic fusion was 73%. The mean preoperative AOFAS score improved from 22.9 to 81.6 at follow-up. There were implant-related complications in 8 toes. Ninety-five percent of the patients were satisfied with the procedure, and 3.3% of the patients needed revision surgery.

CONCLUSION

This technique maintained PIP joint alignment and provided rotational and angular stability with high patient satisfaction and low complication and reoperation rates. We conclude that this is a reproducible technique and an alternative for PIP joint fusions.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Enhanced photonic crystal cavity-waveguide coupling using local slow-light engineering

This Letter introduces an enhanced cavity-waveguide coupling architecture based upon slow-light engineering in a two-port photonic crystal system. After analyzing the system transmittance using coupled-mode theory, the system is probed experimentally and shown to have increased transmittance due to the enhanced cavity-waveguide coupling. Such a coupling architecture may facilitate next-generation planar lightwave circuitry such as onchip quantum information processing or high precision light-matter sensing applications.

Culture of Iris Pigment Epithelial Cells on Expanded-Polytetrafluroethylene (ePTFE) Substrates for the Treatment of Age-Related Macular Degeneration

Introduction:

Transplantation of an intact differentiated retinal pigment epithelial (RPE) cell layer may provide a means to treat Age-Related Macular Degeneration (AMD). However, harvesting RPE cells can be a technically complicated procedure. Our current work aimed to prepare intact differentiated iris pigment epithelial (IPE) cell layers, which are easy to obtain and have the same embryonic origin and similar properties as RPE cells, on ePTFE substrates for transplantation purposes to rescue deteriorated photoreceptors in AMD.

Methods:

IPE cells isolated from rat eyes were seeded on different substrates, including fibronectin n-heptylamine (HA) ePTFE substrates, HA ePTFE substrates, ePTFE substrates and fibronectin tissue culture polystyrene (TCPS) as control. Cell number and morphology were assessed at each time interval. The formation of tight junction was examined by immunostaining of junction proteins.

Results:

An obvious increasing trend of cell number was observed in IPE cells on fibronectin n-heptylamine (HA) ePTFE substrate, exhibiting heavy pigmentation and epithelial morphology. At Day 28, tight junction formation was indicated by cell-cell junctional proteins along cell borders.

Conclusion:

Harvested IPE cells cultured on fibronectin HA-ePTFE substrates can differentiate and form a cell monolayer that may be suitable for transplantation.

Selective epitaxy of semiconductor nanopyramids for nanophotonics

We present a detailed study of the parameters which affect the geometrical perfection of nanopyramids used for the site-selected nucleation of quantum dots. Through an understanding of crystal facet formation, we demonstrate that undesirable high index planes can be suppressed using carefully optimized lithography together with properly orientated source fluxes in the growth reactor. High quality InP nanopyramids are reported with individual InAs/InP quantum dots positioned with high precision. This represents an important milestone for the fabrication of complex quantum dot based nanophotonic devices.

Friction transfer of polytetrafluoroethylene (PTFE) to produce nanoscale features and influence cellular response in vitro

A large number of cell types are known to respond to chemical and topographical patterning of substrates. Friction transfer of polytetrafluoroethylene (PTFE) onto substrates has been shown to produce continuous, straight, parallel nanofibres. Ammonia plasma treatment can be used to defluorinate the PTFE, decreasing the dynamic contact angle. Fibroblast and epithelial cells were elongated and oriented with their long axis parallel to the fibres, both individually and in clusters. The fibres restricted cell migration. Cell alignment was slightly reduced on the plasma-treated fibres. These results indicated that although surface topography can affect cellular response, surface chemistry also mediates the extent of this response.

The comparative effectiveness of group and individually contingent free time with inner-city junior high school students

A major purpose of the study was to assess the relative effects of group versus individually contingent free time in modifying student behaviors. Other purposes were to determine the effectiveness of well-planned lesson activities and tokens without back-up reinforcers. Eight students in an inner-city seventh-grade class of 32 blacks served as subjects. Well-organized lesson activities and success feedback via tokens did not produce high levels of desirable behavior. In contrast, group and individually contingent free time produced substantially higher levels of appropriate behavior than did the baseline conditions. The group reinforcement procedure appeared to be slightly more effective than individual reinforcement.

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.