Conjugation of IL-33 to Microporous Annealed Particle Scaffolds Enhances Type 2-Like Immune Responses In Vitro and In Vivo

The inflammatory foreign body response (FBR) is the main driver of biomaterial implant failure. Current strategies to mitigate the onset of a FBR include modification of the implant surface, release of anti-inflammatory drugs, and cell-scale implant porosity. The microporous annealed particle (MAP) scaffold platform is an injectable, porous biomaterial composed of individual microgels, which are annealed in situ to provide a structurally stable scaffold with cell-scale microporosity. MAP scaffold does not induce a discernible foreign body response in vivo and, therefore, can be used a "blank canvas" for biomaterial-mediated immunomodulation. Damage associated molecular patterns (DAMPs), such as IL-33, are potent regulators of type 2 immunity that play an important role in tissue repair. In this manuscript, IL-33 is conjugated to the microgel building-blocks of MAP scaffold to generate a bioactive material (IL33-MAP) capable of stimulating macrophages in vitro via a ST-2 receptor dependent pathway and modulating immune cell recruitment to the implant site in vivo, which indicates an upregulation of a type 2-like immune response and downregulation of a type 1-like immune response.

Microporous Annealed Particle (MAP) Scaffold Pore Size Influences Mesenchymal Stem Cell Metabolism and Proliferation Without Changing CD73, CD90, and CD105 Expression Over Two Weeks

Scaffold pore architecture is shown to influence stem cell fate through various avenues. It is demonstrated that microporous annealed particle (MAP) microgel diameter can be tuned to control scaffold pore size and, in turn, modulate mesenchymal stem cell (MSC) survivability, proliferation, metabolism, and migration, thereby enhancing bioactivity and guiding future applications of MAP for regenerative medicine.

De novo tissue formation using custom microporous annealed particle hydrogel provides long-term vocal fold augmentation

Biomaterial-enabled de novo formation of non-fibrotic tissue in situ would provide an important tool to physicians. One example application, glottic insufficiency, is a debilitating laryngeal disorder wherein vocal folds do not fully close, resulting in difficulty speaking and swallowing. Preferred management of glottic insufficiency includes bulking of vocal folds via injectable fillers, however, the current options have associated drawbacks including inflammation, accelerated resorption, and foreign body response. We developed a novel iteration of microporous annealed particle (MAP) scaffold designed to provide persistent augmentation. Following a 14-month study of vocal fold augmentation using a rabbit vocal paralysis model, most MAP scaffolds were replaced with tissue de novo that matched the mixture of fibrotic and non-fibrotic collagens of the contralateral vocal tissue. Further, persistent tissue augmentation in MAP-treated rabbits was observed via MRI and via superior vocal function at 14 months relative to the clinical standard.

Activating an adaptive immune response from a hydrogel scaffold imparts regenerative wound healing

Microporous annealed particle (MAP) scaffolds are flowable, in situ crosslinked, microporous scaffolds composed of microgel building blocks and were previously shown to accelerate wound healing. To promote more extensive tissue ingrowth before scaffold degradation, we aimed to slow MAP degradation by switching the chirality of the crosslinking peptides from L- to D-amino acids. Unexpectedly, despite showing the predicted slower enzymatic degradation in vitro, D-peptide crosslinked MAP hydrogel (D-MAP) hastened material degradation in vivo and imparted significant tissue regeneration to healed cutaneous wounds, including increased tensile strength and hair neogenesis. MAP scaffolds recruit IL-33 type 2 myeloid cells, which is amplified in the presence of D-peptides. Remarkably, D-MAP elicited significant antigen-specific immunity against the D-chiral peptides, and an intact adaptive immune system was required for the hydrogel-induced skin regeneration. These findings demonstrate that the generation of an adaptive immune response from a biomaterial is sufficient to induce cutaneous regenerative healing despite faster scaffold degradation.

Patient experiences of receiving arthroscopic surgery or personalised hip therapy for femoroacetabular impingement in the context of the UK fashion study: a qualitative study

BACKGROUND

UK FASHIoN was a multicentre randomised controlled trial comparing hip arthroscopic surgery (HA) with personalised hip therapy (PHT, physiotherapist-led conservative care), for patients with hip pain attributed to femoroacetabular impingement (FAI) syndrome. Our aim was to describe the treatment and trial participation experiences of patients, to contextualise the trial results and offer further information to assist treatment decision-making in FAI.

METHODS

We conducted in-depth semi-structured telephone interviews with a purposive sample of trial participants from each of the trial arms. They were interviewed after they received treatment and completed their first year of trial participation. Thematic analysis and constant comparison analytical approaches were used to identify themes of patient treatment experiences during the trial.

RESULTS

Forty trial participants were interviewed in this qualitative study. Their baseline characteristics were similar to those in the main trial sample. On average, their hip-related quality of life (iHOT-33 scores) at 12 months follow-up were lower than average for all trial participants, indicating poorer hip-related quality of life as a consequence of theoretical sampling. Patient experiences occurred in five patient groups: those who felt their symptoms improved with hip arthroscopy, or with personal hip therapy, patients who felt their hip symptoms did not change with PHT but did not want HA, patients who decided to change from PHT to HA and a group who experienced serious complications after HA. Interviewees mostly described a trouble-free, enriching and altruistic trial participation experience, although most participants expected more clinical follow-up at the end of the trial.

CONCLUSION

Both HA and PHT were experienced as beneficial by participants in the trial. Treatment success appeared to depend partly on patients' prior own expectations as well as their outcomes, and future research is needed to explore this further. Findings from this study can be combined with the primary results to inform future FAI patients.

TRIAL REGISTRATION

Arthroscopic surgery for hip impingement versus best conventional care ( ISRCTN64081839 ). 28/02/2014.

Selective and Improved Photoannealing of Microporous Annealed Particle (MAP) Scaffolds

Microporous annealed particle (MAP) scaffolds consist of a slurry of hydrogel microspheres that undergo annealing to form a solid scaffold. MAP scaffolds have contained functional groups with dual abilities to participate in Michael-type addition (gelation) and radical polymerization (photoannealing). Functional groups with efficient Michael-type additions react with thiols and amines under physiological conditions, limiting usage for therapeutic delivery. We present a heterofunctional maleimide/methacrylamide 4-arm PEG macromer (MethMal) engineered for selective photopolymerization compatible with multiple polymer backbones. Rheology using two classes of photoinitiators demonstrates advantageous photopolymerization capabilities. Functional assays show benefits for therapeutic delivery and 3D printing without impacting cell viability.

Systematic review of the current status of cadaveric simulation for surgical training

Background

There is growing interest in and provision of cadaveric simulation courses for surgical trainees. This is being driven by the need to modernize and improve the efficiency of surgical training within the current challenging training climate. The objective of this systematic review is to describe and evaluate the evidence for cadaveric simulation in postgraduate surgical training.

Methods

A PRISMA‐compliant systematic literature review of studies that prospectively evaluated a cadaveric simulation training intervention for surgical trainees was undertaken. All relevant databases and trial registries were searched to January 2019. Methodological rigour was assessed using the widely validated Medical Education Research Quality Index (MERSQI) tool.

Results

A total of 51 studies were included, involving 2002 surgical trainees across 69 cadaveric training interventions. Of these, 22 assessed the impact of the cadaveric training intervention using only subjective measures, five measured impact by change in learner knowledge, and 23 used objective tools to assess change in learner behaviour after training. Only one study assessed patient outcome and demonstrated transfer of skill from the simulated environment to the workplace. Of the included studies, 67 per cent had weak methodology (MERSQI score less than 10·7).

Conclusion

There is an abundance of relatively low‐quality evidence showing that cadaveric simulation induces short‐term skill acquisition as measured by objective means. There is currently a lack of evidence of skill retention, and of transfer of skills following training into the live operating theatre.

Enhanced In Vivo Delivery of Stem Cells using Microporous Annealed Particle Scaffolds

Delivery to the proper tissue compartment is a major obstacle hampering the potential of cellular therapeutics for medical conditions. Delivery of cells within biomaterials may improve localization, but traditional and newer void-forming hydrogels must be made in advance with cells being added into the scaffold during the manufacturing process. Injectable, in situ cross-linking microporous scaffolds are recently developed that demonstrate a remarkable ability to provide a matrix for cellular proliferation and growth in vitro in three dimensions. The ability of these scaffolds to deliver cells in vivo is currently unknown. Herein, it is shown that mesenchymal stem cells (MSCs) can be co-injected locally with microparticle scaffolds assembled in situ immediately following injection. MSC delivery within a microporous scaffold enhances MSC retention subcutaneously when compared to cell delivery alone or delivery within traditional in situ cross-linked nanoporous hydrogels. After two weeks, endothelial cells forming blood vessels are recruited to the scaffold and cells retaining the MSC marker CD29 remain viable within the scaffold. These findings highlight the utility of this approach in achieving localized delivery of stem cells through an injectable porous matrix while limiting obstacles of introducing cells within the scaffold manufacturing process.

The prevalence of cam hip morphology in a general population sample

OBJECTIVE

Cam hip morphology is associated with femoroacetabular impingement (FAI) syndrome and causes hip osteoarthritis (OA). We aimed to assess the prevalence of cam hip morphology in a sample representative of the general population, using a measure with a predefined diagnostic accuracy.

DESIGN

Patients aged 16-65, who were admitted to a major trauma centre and received a computed tomography (CT) pelvis were retrospectively screened for eligibility. Subjects with proximal femoral, acetabular or pelvic fractures and those who were deceased were excluded. Eligible subjects were divided into 10 groups based on gender and age. 20 subjects from each group were included. Subjects' index of multiple deprivation (IMD) and ethnicity were recorded. CT imaging was assessed and alpha angles (a measure of cam morphology) measured in the anterosuperior aspect of the femoral head neck junction. An alpha angle greater than 60° was considered to represent cam morphology. This measure and technique has a predefined sensitivity of 80% and specificity of 73% to detect cam morphology associated with FAI syndrome. The prevalence of cam morphology was reported as a proportion of subjects affected with 95% confidence intervals.

RESULTS

200 subjects were included. The sample was broadly representative of the UK general population in terms of IMD. 155 subjects (86%) identified as white. Cam morphology was present in 47% (95% CI 42,51) of subjects.

CONCLUSIONS

In this sample, broadly representative of the UK general population 47% of subjects had cam hip morphology; a hip shape associated with FAI syndrome and OA.

The Warwick Agreement on femoroacetabular impingement syndrome (FAI syndrome): an international consensus statement

The 2016 Warwick Agreement on femoroacetabular impingement (FAI) syndrome was convened to build an international, multidisciplinary consensus on the diagnosis and management of patients with FAI syndrome. 22 panel members and 1 patient from 9 countries and 5 different specialties participated in a 1-day consensus meeting on 29 June 2016. Prior to the meeting, 6 questions were agreed on, and recent relevant systematic reviews and seminal literature were circulated. Panel members gave presentations on the topics of the agreed questions at Sports Hip 2016, an open meeting held in the UK on 27-29 June. Presentations were followed by open discussion. At the 1-day consensus meeting, panel members developed statements in response to each question through open discussion; members then scored their level of agreement with each response on a scale of 0-10. Substantial agreement (range 9.5-10) was reached for each of the 6 consensus questions, and the associated terminology was agreed on. The term 'femoroacetabular impingement syndrome' was introduced to reflect the central role of patients' symptoms in the disorder. To reach a diagnosis, patients should have appropriate symptoms, positive clinical signs and imaging findings. Suitable treatments are conservative care, rehabilitation, and arthroscopic or open surgery. Current understanding of prognosis and topics for future research were discussed. The 2016 Warwick Agreement on FAI syndrome is an international multidisciplinary agreement on the diagnosis, treatment principles and key terminology relating to FAI syndrome.Author note The Warwick Agreement on femoroacetabular impingement syndrome has been endorsed by the following 25 clinical societies: American Medical Society for Sports Medicine (AMSSM), Association of Chartered Physiotherapists in Sports and Exercise Medicine (ACPSEM), Australasian College of Sports and Exercise Physicians (ACSEP), Austian Sports Physiotherapists, British Association of Sports and Exercise Medicine (BASEM), British Association of Sport Rehabilitators and Trainers (BASRaT), Canadian Academy of Sport and Exercise Medicine (CASEM), Danish Society of Sports Physical Therapy (DSSF), European College of Sports and Exercise Physicians (ECOSEP), European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA), Finnish Sports Physiotherapist Association (SUFT), German-Austrian-Swiss Society for Orthopaedic Traumatologic Sports Medicine (GOTS), International Federation of Sports Physical Therapy (IFSPT), International Society for Hip Arthroscopy (ISHA), Groupo di Interesse Specialistico dell'A.I.F.I., Norwegian Association of Sports Medicine and Physical Activity (NIMF), Norwegian Sports Physiotherapy Association (FFI), Society of Sports Therapists (SST), South African Sports Medicine Association (SASMA), Sports Medicine Australia (SMA), Sports Doctors Australia (SDrA), Sports Physiotherapy New Zealand (SPNZ), Swedish Society of Exercise and Sports Medicine (SFAIM), Swiss Society of Sports Medicine (SGMS/SGSM), Swiss Sports Physiotherapy Association (SSPA).

Particle Hydrogels Based on Hyaluronic Acid Building Blocks

The extracellular matrix (ECM) provides tissues with the mechanical support, space, and bioactive signals needed for homeostasis or tissue repair after wounding or disease. Hydrogel based scaffolds that can match the bulk mechanical properties of the target tissue have been extensively explored as ECM mimics. Although the addition of microporosity to hydrogel scaffolds has been shown to enhance cell/tissue-material integration, the introduction of microporosity often involves harsh chemical methods, which limit bioactive signal incorporation and injectability. Particle hydrogels are an emerging platform to generate in situ forming microporous scaffolds. In this approach, μgel particles are annealed to each other to form a bulk scaffold that is porous because of the void space left by the packed microgels. In the present work, we discuss the formation of hyaluronic acid-based microfluidic generated microgels for the generation of a completely biodegradable material. The generation of particle scaffolds requires two orthogonal chemistries, one for microgel generation and one for microgel annealing and scaffold formation. Here we explore three orthogonal annealing chemistries based on an enzymatic reaction, light based radical polymerization, and amine/carboxylic acid based cross-linking to demonstrate the versatility of our particle hydrogels and explore potential physical differences between the approaches. We explore the connectivity of the generated pores, the pore area/void fraction of the resulting scaffold, the mechanical properties of the scaffold, and cell spreading within scaffolds formed with the three different annealing mechanisms.

Protocol for a multicentre, parallel-arm, 12-month, randomised, controlled trial of arthroscopic surgery versus conservative care for femoroacetabular impingement syndrome (FASHIoN)

INTRODUCTION

Femoroacetabular impingement (FAI) syndrome is a recognised cause of young adult hip pain. There has been a large increase in the number of patients undergoing arthroscopic surgery for FAI; however, a recent Cochrane review highlighted that there are no randomised controlled trials (RCTs) evaluating treatment effectiveness. We aim to compare the clinical and cost-effectiveness of arthroscopic surgery versus best conservative care for patients with FAI syndrome.

METHODS

We will conduct a multicentre, pragmatic, assessor-blinded, two parallel arm, RCT comparing arthroscopic surgery to physiotherapy-led best conservative care. 24 hospitals treating NHS patients will recruit 344 patients over a 26-month recruitment period. Symptomatic adults with radiographic signs of FAI morphology who are considered suitable for arthroscopic surgery by their surgeon will be eligible. Patients will be excluded if they have radiographic evidence of osteoarthritis, previous significant hip pathology or previous shape changing surgery. Participants will be allocated in a ratio of 1:1 to receive arthroscopic surgery or conservative care. Recruitment will be monitored and supported by qualitative intervention to optimise informed consent and recruitment. The primary outcome will be pain and function assessed by the international hip outcome tool 33 (iHOT-33) measured 1-year following randomisation. Secondary outcomes include general health (short form 12), quality of life (EQ5D-5L) and patient satisfaction. The primary analysis will compare change in pain and function (iHOT-33) at 12 months between the treatment groups, on an intention-to-treat basis, presented as the mean difference between the trial groups with 95% CIs. The study is funded by the Health Technology Assessment Programme (13/103/02).

ETHICS AND DISSEMINATION

Ethical approval is granted by the Edgbaston Research Ethics committee (14/WM/0124). The results will be disseminated through open access peer-reviewed publications, including Health Technology Assessment, and presented at relevant conferences.

TRIAL REGISTRATION NUMBER

ISRCTN64081839; Pre-results.

Prevalence of cam hip shape morphology: a systematic review

OBJECTIVE

Cam hip shape morphology is a recognised cause of femoroacetabular impingement (FAI) and is associated with hip osteoarthritis. Our aim was to systematically review the available epidemiological evidence assessing the prevalence of cam hip shape morphology in the general population and any studied subgroups including subjects with and without hip pain.

DESIGN

All studies that reported the prevalence of cam morphology, measured by alpha angles, in subjects aged 18 and over, irrespective of study population or presence of hip symptoms were considered for inclusion. We searched AMED, MEDLINE, EMBASE, CINAHL and CENTRAL in October 2015. Two authors independently identified eligible studies and assessed risk of bias. We planned to pool data of studies considered clinically homogenous.

RESULTS

Thirty studies met inclusion criteria. None of the included studies were truly population-based: three included non-representative subgroups of the general population, 19 included differing clinical populations, while eight included professional athletes. All studies were judged to be at high risk of bias. Due to substantial clinical heterogeneity meta analysis was not possible. Across all studies, the prevalence estimates of cam morphology ranged from 5 to 75% of participants affected. We were unable to demonstrate a higher prevalence in selected subgroups such as athletes or those with hip pain.

CONCLUSIONS

There is currently insufficient high quality data to determine the true prevalence of cam morphology in the general population or selected subgroups. Well-designed population-based epidemiological studies that use homogenous case definitions are required to determine the prevalence of cam morphology and its relationship to hip pain.

Accelerated wound healing by injectable microporous gel scaffolds assembled from annealed building blocks

Injectable hydrogels can provide a scaffold for in situ tissue regrowth and regeneration, yet gel degradation before tissue reformation limits the gels' ability to provide physical support. Here, we show that this shortcoming can be circumvented through an injectable, interconnected microporous gel scaffold assembled from annealed microgel building blocks whose chemical and physical properties can be tailored by microfluidic fabrication. In vitro, cells incorporated during scaffold formation proliferated and formed extensive three-dimensional networks within 48 h. In vivo, the scaffolds facilitated cell migration that resulted in rapid cutaneous-tissue regeneration and tissue-structure formation within five days. The combination of microporosity and injectability of these annealed gel scaffolds should enable novel routes to tissue regeneration and formation in vivo.

Hybrid photopatterned enzymatic reaction (HyPER) for in situ cell manipulation

The ability to design artificial extracellular matrices as cell-instructive scaffolds has opened the door to technologies capable of studying the fate of cells in vitro and to guiding tissue repair in vivo. One main component of the design of artificial extracellular matrices is the incorporation of biochemical cues to guide cell phenotype and multicellular organization. The extracellular matrix (ECM) is composed of a heterogeneous mixture of proteins that present a variety of spatially discrete signals to residing cell populations. In contrast, most engineered ECMs do not mimic this heterogeneity. In recent years, photo-deprotection has been used to spatially immobilize signals. However, this approach has been limited mostly to small peptides. Here we combine photo-deprotection with enzymatic reaction to achieve spatially controlled immobilization of active bioactive signals that range from small molecules to large proteins. A peptide substrate for transglutaminase factor XIII (FXIIIa) was caged with a photo-deprotectable group, which was then immobilized to the bulk of a cell-compatible hydrogel. With focused light, the substrate can be deprotected and used to immobilize patterned bioactive signals. This approach offers an innovative strategy to immobilize delicate bioactive signals, such as growth factors, without loss of activity and enables in situ cell manipulation of encapsulated cells.

The effect of surgical approach on the histologyof the femoral head following resurfacing of the hip: Analysis of retrieval specimens

OBJECTIVES

We aimed to determine the effect of surgical approach on the histology of the femoral head following resurfacing of the hip.

METHODS

We performed a histological assessment of the bone under the femoral component taken from retrieval specimens of patients having revision surgery following resurfacing of the hip. We compared the number of empty lacunae in specimens from patients who had originally had a posterior surgical approach with the number in patients having alternative surgical approaches.

RESULTS

We found a statistically significant increase in the percentage of empty lacunae in retrieval specimens from patients who had the posterior approach compared with other surgical approaches (p < 0.001).

CONCLUSIONS

This indicates that the vascular compromise that occurs during the posterior surgical approach does have long-term effects on the bone of the femoral head, even if it does not cause overt avascular necrosis. Cite this article: Bone Joint Res 2013;2:200-5.

Steric effects in peptide and protein exchange with activated disulfides

Disulfide exchange is an important bioconjugation tool, enabling chemical modification of peptides and proteins containing free cysteines. We previously reported the synthesis of a macromer bearing an activated disulfide and its incorporation into hydrogels. Despite their ability to diffuse freely into hydrogels, larger proteins were unable to undergo in-gel disulfide exchange. In order to understand this phenomenon, we synthesized four different activated disulfide-bearing model compounds (Mn = 300 Da to 10 kDa) and quantified their rate of disulfide exchange with a small peptide (glutathione), a moderate-sized protein (β-lactoglobulin), and a large protein (bovine serum albumin) in four different pH solutions (6.0, 7.0, 7.4, and 8.0) to mimic biological systems. Rate constants of exchange depend significantly on the size and accessibility of the thiolate. pH also significantly affects the rate of reaction, with the faster reactions occurring at higher pH. Surprisingly, little difference in exchange rates is seen between macromolecular disulfides of varying size (Mn = 2 kDa - 10 kDa), although all undergo exchange more slowly than their small molecule analogue (MW = 300 g/mol). The maximum exchange efficiencies (% disulfides exchanged after 24 h) are not siginificantly affected by thiol size or pH, but somewhat affected by disulfide size. Therefore, while all three factors investigated (pH, disulfide size, and thiolate size) can influence the exchange kinetics and extent of reaction, the size of the thiolate and its accessibility plays the most significant role.

Synthesis of photodegradable macromers for conjugation and release of bioactive molecules

Hydrogel scaffolds are used in biomedicine to study cell differentiation and tissue evolution, where it is critical to control the delivery of chemical cues both spatially and temporally. While large molecules can be physically entrapped in a hydrogel, moderate molecular weight therapeutics must be tethered to the hydrogel network through a labile linkage to allow controlled release. We synthesized and characterized a library of polymerizable ortho-nitrobenzyl (o-NB) macromers with different functionalities at the benzylic position (alcohol, amine, BOC-amine, halide, acrylate, carboxylic acid, activated disulfide, N-hydroxysuccinyl ester, biotin). This library of polymerizable macromers containing o-NB groups should allow direct conjugation of nearly any type of therapeutic agent and its subsequent controlled photorelease from a hydrogel network. As proof-of-concept, we incorporated the N-hydroxysuccinyl ester macromer into hydrogels and then reacted phenylalanine with the NHS ester. Upon exposure to light (λ = 365 nm; 10 mW/cm(2), 10 min), 81.3% of the phenylalanine was released from the gel. Utilizing the photodegradable macromer incorporating an activated disulfide, we conjugated a cell-adhesive peptide (GCGYGRGDSPG), a protein that exhibits enzymatic activity (bovine serum albumin (BSA)), and a growth factor (transforming growth factor-β1 (TGF-β1)) into hydrogels, controlled their release with light (λ = 365 nm; 10 mW/cm(2), 0-20 min), and verified the bioactivity of the photoreleased molecules. The photoreleasable peptide allows real-time control over cell adhesion. BSA maintains full enzymatic activity upon sequestration and release from the hydrogel. Photoreleased TGF-β1 is able to induce chondrogenic differentiation of human mesenchymal stem cells comparable to native TGF-β1. Through this approach, we have demonstrated that photodegradable tethers can be used to sequester peptides and proteins into hydrogel depots and release them in an externally controlled, predictable manner without compromising biological function.

Photo-selective delivery of model therapeutics from hydrogels

Hydrogels are commonly used in biomedical applications to sequester and release therapeutics. Covalently tethering therapeutic agents to a hydrogel through a degradable linkage allows their controlled release, but temporally separating the release of multiple therapeutics from a single hydrogel remains a major challenge. In this report, we use of a series of photodegradable ortho-nitrobenzyl (o-NB) groups with varying structures to link model therapeutic agents (fluorescein, rhodamine and aminomethylcoumarin acetate) to poly(ethylene glycol) macromers. We polymerized the macromers into hydrogel networks via redox polymerization and quantified the apparent rate constants of degradation (k_app) of each of the photoreleasable compounds. By exploiting differences in reactivity of the different o-NB groups, we are able to create complex, multi-stage release profiles. We demonstrate the ability to switch between concurrent and biased release of model therapeutics simply by switching wavelengths. We also demonstrate a complex four-stage release profile in which the release of three separate model therapeutics is controlled by varying wavelength, intensity and exposure time. This is the first report of photo-selective release of therapeutics from a hydrogel, allowing user-dictated real-time spatial and temporal control over multiple chemical signals in a cell microenvironment in 2D and 3D.

Photodegradable macromers and hydrogels for live cell encapsulation and release

Hydrogel scaffolds are commonly used as 3D carriers for cells because their properties can be tailored to match natural extracellular matrix. Hydrogels may be used in tissue engineering and regenerative medicine to deliver therapeutic cells to injured or diseased tissue through controlled degradation. Hydrolysis and enzymolysis are the two most common mechanisms employed for hydrogel degradation, but neither allows sequential or staged release of cells. In contrast, photodegradation allows external real-time spatial and temporal control over hydrogel degradation, and allows for staged and sequential release of cells. We synthesized and characterized a series of macromers incorporating photodegradbale ortho-nitrobenzyl (o-NB) groups in the macromer backbone. We formed hydrogels from these macromers via redox polymerization and quantified the apparent rate constants of degradation (kapp) of each via photorheology at 370 nm, 10 mW/cm(2). Decreasing the number of aryl ethers on the o-NB group increases kapp, and changing the functionality from primary to seconday at the benzylic site dramatically increases kapp. Human mesenchymal stem cells (hMSCs) survive encapsulation in the hydrogels (90% viability postencapsulation). By exploiting the differences in reactivity of two different o-NB linkers, we quantitatively demonstrate the biased release of one stem cell population (green-fluoroescent protein expressing hMSCs) over another (red-fluorescent protein expressing hMSCs).

Scintigraphic assessment of bone status at one year following hip resurfacing: Comparison of two surgical approaches using SPECT-CT scan

Objectives

To study the vascularity and bone metabolism of the femoral head/neck following hip resurfacing arthroplasty, and to use these results to compare the posterior and the trochanteric-flip approaches.

Methods

In our previous work, we reported changes to intra-operative blood flow during hip resurfacing arthroplasty comparing two surgical approaches. In this study, we report the vascularity and the metabolic bone function in the proximal femur in these same patients at one year after the surgery. Vascularity and bone function was assessed using scintigraphic techniques. Of the 13 patients who agreed to take part, eight had their arthroplasty through a posterior approach and five through a trochanteric-flip approach.

Results

One year after surgery, we found no difference in the vascularity (vascular phase) and metabolic bone function (delayed phase) at the junction of the femoral head/neck between the two groups of patients. Higher radiopharmaceutical uptake was found in the region of the greater trochanter in the trochanteric-flip group, related to the healing osteotomy.

Conclusions

Our findings using scintigraphic techniques suggest that the greater intra-operative reduction in blood flow to the junction of the femoral head/neck, which is seen with the posterior approach compared with trochanteric flip, does not result in any difference in vascularity or metabolic bone function one year after surgery.

Establishing a range of motion boundary for total hip arthroplasty

Range of motion of the hip joint is a major contributor to dislocation post total hip replacement. Impingement is often treated as a surrogate for dislocation and occurs – prosthetically – when the neck of the femoral component contacts with the rim of the pelvic acetabular cup. This impingement is caused by movement of the leg during activities of daily living. This article analyses hip joint range of motion and its implication for impingement. A systematic literature review was undertaken with the purpose of establishing a range of motion benchmark for total hip replacement. This paper proposes a method by which a three-dimensional range of motion boundary established from the literature can be presented. The nominal boundary is also validated experimentally using a number of configurations of a neutral hip joint coordinate frame.

New aids for the non-invasive prenatal diagnosis of achondroplasia: dysmorphic features, charts of fetal size and molecular confirmation using cell-free fetal DNA in maternal plasma

OBJECTIVES

To improve the prenatal diagnosis of achondroplasia by constructing charts of fetal size, defining frequency of sonographic features and exploring the role of non-invasive molecular diagnosis based on cell-free fetal deoxyribonucleic acid (DNA) in maternal plasma.

METHODS

Data on fetuses with a confirmed diagnosis of achondroplasia were obtained from our databases, records reviewed, sonographic features and measurements determined and charts of fetal size constructed using the LMS (lambda-mu-sigma) method and compared with charts used in normal pregnancies. Cases referred to our regional genetics laboratory for molecular diagnosis using cell-free fetal DNA were identified and results reviewed.

RESULTS

Twenty-six cases were scanned in our unit. Fetal size charts showed that femur length was usually on or below the 3(rd) centile by 25 weeks' gestation, and always below the 3(rd) by 30 weeks. Head circumference was above the 50(th) centile, increasing to above the 95(th) when compared with normal for the majority of fetuses. The abdominal circumference was also increased but to a lesser extent. Commonly reported sonographic features were bowing of the femora, frontal bossing, short fingers, a small chest and polyhydramnios. Analysis of cell-free fetal DNA in six pregnancies confirmed the presence of the c.1138G > A mutation in the FGRF3 gene in four cases with achondroplasia, but not the two subsequently found to be growth restricted.

CONCLUSIONS

These data should improve the accuracy of diagnosis of achondroplasia based on sonographic findings, and have implications for targeted molecular confirmation that can reliably and safely be carried out using cell-free fetal DNA.

Brachmann-de Lange syndrome: definition of prenatal sonographic features to facilitate definitive prenatal diagnosis

OBJECTIVE

The objective was to improve the prenatal diagnosis of Brachmann-de Lange syndrome (BDLS) by defining the sonographic criteria.

METHODS

Retrospective review of Fetal Medicine Unit (FMU) notes from 1998 to 2009 to identify all cases seen with a final diagnosis of BDLS. Literature review undertaken to ascertain all cases where sonographic features of BDLS had been described. Information was pooled to define the most common features.

RESULTS

Seven cases were identified from review of FMU records. The diagnosis was suspected prenatally in four of the seven. All had asymmetrical forearm defects with oligodactyly/polydactyly, five had intrauterine growth restriction (IUGR) and five had abnormal facial features including micrognathia and/or a long overhanging philtrum. A further 28 cases were identified in the literature, but the diagnosis was only suspected prenatally in nine. Overall the most common feature was IUGR (80%); upper limb anomalies were detected in nearly half of cases. Other common features included facial anomalies (40%), diaphragmatic hernia (34%), increased nuchal translucency/fold (37%) and cardiac anomalies (14%).

CONCLUSIONS

Identification of asymmetrical oligodactyly with or without forearm anomalies associated with microcephaly and/or IUGR or diaphragmatic hernia are findings that should arouse suspicion of BDLS, although definitive diagnosis at present would have to await delivery in the majority of cases.

Cancellation of elective surgery – any improvement after ten years?

Cancellation of elective operations represents a waste of resources and a poor standard of service to patients who may already have spent several months on a waiting list. The purpose of this study was to determine the extent of the problem in a typical district general hospital, how it has changed over a period of ten years and whether alterations in resource management in the admission process have led to improvements in service.

New evidence of animal consciousness

This paper reviews evidence that increases the probability that many animals experience at least simple levels of consciousness. First, the search for neural correlates of consciousness has not found any consciousness-producing structure or process that is limited to human brains. Second, appropriate responses to novel challenges for which the animal has not been prepared by genetic programming or previous experience provide suggestive evidence of animal consciousness because such versatility is most effectively organized by conscious thinking. For example, certain types of classical conditioning require awareness of the learned contingency in human subjects, suggesting comparable awareness in similarly conditioned animals. Other significant examples of versatile behavior suggestive of conscious thinking are scrub jays that exhibit all the objective attributes of episodic memory, evidence that monkeys sometimes know what they know, creative tool-making by crows, and recent interpretation of goal-directed behavior of rats as requiring simple nonreflexive consciousness. Third, animal communication often reports subjective experiences. Apes have demonstrated increased ability to use gestures or keyboard symbols to make requests and answer questions; and parrots have refined their ability to use the imitation of human words to ask for things they want and answer moderately complex questions. New data have demonstrated increased flexibility in the gestural communication of swarming honey bees that leads to vitally important group decisions as to which cavity a swarm should select as its new home. Although no single piece of evidence provides absolute proof of consciousness, this accumulation of strongly suggestive evidence increases significantly the likelihood that some animals experience at least simple conscious thoughts and feelings. The next challenge for cognitive ethologists is to investigate for particular animals the content of their awareness and what life is actually like, for them.

Is the universe designed? Yes and no

Addressing the title's question from the perspective of Whitehead's process theology, fourteen basic notions of which are explained, I argue that the universe is not designed in six common senses of that notion: It was not created out of nothing, all at once, through punctuated creationism, from a blueprint, solely for humans, or even with humans specifically in mind. But it is designed in two looser senses of the term: It reflects a divine aim at richness of experience, and it involved a divine establishment of this cosmic epoch's fundamental contingent principles--an idea that is consistent with process theism's view of divine power as purely persuasive.

Asymmetric ketone reduction with immobilized yeast in hexane: biocatalyst deactivation and regeneration

There is a need to develop methods for producing enantiomerically pure pharmaceuticals because the racemic mixtures made today will probably not be allowed in the future. Synthetic chiral catalysts are being developed for this purpose, as well as new product separation techniques. Another possible option is to use biocatalysts, such as purified enzymes or whole microbial cells, since these can result in the production of mostly a single enantiomer. This study emphasizes the use of alginate-entrapped yeast cells to catalyze the reduction of ketones as a model system. The emphasis is on the factors that might limit the reactivity of such cells, such as equilibrium conditions, substrate or product inhibition, solvent toxicity, loss of cell viability, or the degradation of intracellular levels of enzymes or cofactors. It was found that there was a progressive loss of catalytic activity of the immobilized yeast cells, which appeared to be mainly associated with a loss of cell viability and a decline of intracellular NAD(H) levels during the reaction. The other factors investigated did not have a large effect. A regeneration scheme was developed in order to replenish the intracellular NAD(H) lost during the reaction, which involved removing the biocatalyst from the reaction and supplying the cells with a nutrient source. This resulted in an increase in the NAD(H) to initial levels and also resulted in a maintenance of the ketone reduction rate over time.

Prenatal features of Noonan syndrome

We report six cases of Noonan syndrome which presented prenatally with sonographic abnormalities. These included increased nuchal fluid, short femora, pleural effusions, hydrops, cardiac and renal abnormalities. A review of all cases of Noonan syndrome seen at two regional genetics centres confirms the association with these sonographic abnormalities. These cases demonstrate the diversity of prenatal presentation of Noonan syndrome and highlight the need to consider this diagnosis, particularly when faced with a fetus with a normal karyotype and varying degrees of oedema or hydrops, with a short femur length.

Complications of arthroscopy of the hip

Although arthroscopy of the hip is being carried out increasingly, little is known about the rate of associated complications. We describe a prospective study of 640 consecutive procedures in which a consistent technique was used. The overall complication rate was 1.6%. Complications, none of which was major or long-term, included transient palsy of the sciatic and femoral nerves, perineal injury, bleeding from the portal wounds, trochanteric bursitis and intra-articular breakage of the instrument. We believe that it is possible to undertake this operation safely using the technique described.

Diagnostic and therapeutic impact of MRI and arthrography in the investigation of full-thickness rotator cuff tears

Investigation of shoulder pain is important before surgical treatment. The presence or absence of a full-thickness rotator cuff tear (FTRCT) may determine the type of surgical treatment. Both MRI and conventional arthrography can be used, but little is known about their relative diagnostic and therapeutic impact. We performed a prospective trial assessing: (a) the influence of MRI and arthrography results on the clinician's diagnostic thinking (diagnostic impact); (b) the influence of the results on the clinician's therapeutic thinking (therapeutic impact); and (c) the diagnostic performance of the two techniques in patients with surgical confirmation. A total of 104 consecutive patients with shoulder problems referred to a specialist orthopaedic shoulder clinic underwent pre-operative investigation with MRI and arthrography. The surgeon's diagnosis, diagnostic confidence and planned treatment were measured before the investigation, and then again after the results of each investigation. Before the presentation of the investigation, results, the patients were randomised into two groups. In one group MRI was presented first; in the other group, arthrography. The MRI results led to fewer changes in diagnostic category (14 of 46, 30%) than arthrography (20 of 54, 37%), but the difference was not significant (P > 0.5). Magnetic resonance imaging led to slightly more changes in planned management (17 of 47, 36%) than arthrography (14 of 55, 25%), but again the difference was not statistically significant (P > 0.3). The results of the second investigation always had less diagnostic and therapeutic impact than the first. The accuracy of MRI for FTRCT in 38 patients with surgical confirmation was 79%, sensitivity 81% and specificity 78%; the accuracy of arthrography was 82%, sensitivity 50% and specificity 96%. The clinical diagnosis and management plan can be adequately defined by a single radiological investigation. Magnetic resonance imaging and arthrography had fairly similar diagnostic and therapeutic impact and comparable accuracy, although MRI was more sensitive and less specific. Magnetic resonance imaging may be the preferred investigation because of its better demonstration of soft tissue anatomy.

Postherpetic neuralgia: impact of famciclovir, age, rash severity, and acute pain in herpes zoster patients

New and previously reported analyses of the data from a placebo-controlled trial of famciclovir are reviewed in light of recently proposed recommendations for the analysis of pain in herpes zoster trials. The analyses examined the effect of famciclovir treatment on the duration of postherpetic neuralgia (PHN), which was defined as pain persisting after rash healing, pain persisting > 30 days after study enrollment, or pain persisting > 3 months after study enrollment; the baseline characteristics of patients in the famciclovir and placebo groups who developed PHN; the impact of famciclovir treatment on the duration of PHN, while controlling for significant covariates; and the prevalence of PHN at monthly intervals from 30 to 180 days after enrollment. The results of these analyses indicated that greater age, rash severity, and acute pain severity are risk factors for prolonged PHN. In addition, they demonstrated that treatment of acute herpes zoster patients with famciclovir significantly reduces both the duration and prevalence of PHN.

A comparison of the relative costs of cast treatment and intramedullary nailing for tibial diaphyseal fractures in the UK

A retrospective study was undertaken to compare the costs of treating tibial diaphyseal fractures non-operatively in a cast or operatively with locked intramedullary nailing. In total 39 patients with isolated closed or grade I open, two-part, displaced tibial diaphyseal fractures were studied. Of these, 18 were treated by manipulation under anaesthesia and cast immobilization, and 21 by closed, reamed, locked intramedullary nailing. A detailed analysis of the cost of treatment of each patient was performed and analysed in terms of the in-hospital costs and the overall costs, taking into account time off work. The mean hospital costs were 2226 pounds for plaster treatment and 3727 pounds for intramedullary nailing (significantly different, p < 0.05). The mean time off work was 9 weeks longer in the plaster group and when the cost of lost production through time off work was added to the hospital costs, the overall costs of plaster treatment and intramedullary nailing were 6810 Pounds and 6592 Pounds (difference not significant). This study suggests that the cost to the hospital of treating these fractures is less with plaster treatment but that the overall cost to the community is no different.

Windows on animal minds

The simple kinds of conscious thinking that probably occur in nonhuman animals can be studied objectively by utilizing the same basic procedure that we use every day to infer what our human companions think and feel. This is to base such inferences on communicative behavior, broadly defined to include human language, nonverbal communication, and semantic communication in apes, dolphins, parrots, and honeybees. It seems likely that animals often experience something similar to the messages they communicate. Although this figurative window on other minds is obviously imperfect, it is already contributing significantly to our growing understanding and appreciation of animal mentality.

Prenatal ultrasound findings in a fetus with otopalatodigital syndrome type II

We describe the prenatal diagnosis and post mortem findings, including fetal radiographs and bone histology, in a fetus with oto-palato-digital syndrome type II. The differential diagnosis and recurrence risks are discussed.