The Learning Curve of Third-Generation Percutaneous Chevron and Akin Osteotomy (PECA) for Hallux Valgus.

The learning curve to reach technical proficiency for third-generation percutaneous or minimally invasive chevron and Akin osteotomies (PECA/MICA) is recognized to be steep however it is poorly defined in the literature. This study is a retrospective review of the first 58 consecutive PECA cases of a single surgeon. The primary outcome was the number of cases required to reach technical proficiency as defined by the operation time. Secondary outcomes included radiation exposure, radiographic deformity correction, and complication rates. Between November 2017 and March 2019, 61 consecutive PECA cases were performed with outcome data available for 58 of these (95%). Technical proficiency was reached after 38 cases. Operation time and radiation exposure significantly decreased after this transition point (p < .05). There was no difference in complication rate or radiographic deformity correction regardless of position along the learning curve (p > .05). In conclusion, the mean number of cases required to reach technical proficiency in third-generation PECA is 38 cases. The complication rate does not correlate to the number of cases performed, therefore surgeons interested in learning minimally invasive surgery can be reassured that there is unlikely to be an additional risk of harm to a patient during the learning curve.

Drosophila melanogaster and worker honeybees (Apis mellifera) do not require olfaction to be susceptible to honeybee queen mandibular pheromone.

Eusociality is characterised by the reproductive division of labour; a dominant female (queen) or females are responsible for the majority of reproduction, and subordinate females are reproductively constrained. Reproductive constraint can be due to behavioural aggression and/or chemical cues, so-called queen pheromones, produced by the dominant females. In the honeybee, Apis mellifera, this repressive queen pheromone is queen mandibular pheromone (QMP). The mechanism by which honeybee workers are susceptible to QMP is not yet completely understood, however it is thought to be through olfaction via the antennae and/or gustation via trophallaxis. We have investigated whether olfaction is key to sensing of QMP, using both Drosophila melanogaster- a tractable non-eusocial insect which is also reproductively repressed by QMP- and the target species, A. mellifera worker honeybees. D. melanogaster are still capable of sensing and responding to QMP without their antenna and maxillary palps, and therefore without olfactory receptors. When worker honeybees were exposed to QMP but unable to physically interact with it, therefore required to use olfaction, they were similarly not reproductively repressed. Combined, these findings support either a non-olfactory based mechanism for the repression of reproduction via QMP, or redundancy via non-olfactory mechanisms in both D. melanogaster and A. mellifera. This study furthers our understanding of how species are susceptible to QMP, and provides insight into the mechanisms governing QMP responsiveness in these diverse species.

Evolution of the Torso activation cassette, a pathway required for terminal patterning and moulting.

Embryonic terminal patterning and moulting are critical developmental processes in insects. In Drosophila and Tribolium both of these processes are regulated by the Torso-activation cassette (TAC). The TAC consists of a common receptor, Torso, ligands Trunk and prothoracicotropic hormone (PTTH), and the spatially restricted protein Torso-like, with combinations of these elements acting mechanistically to activate the receptor in different developmental contexts. In order to trace the evolutionary history of the TAC we determined the presence or absence of TAC components in the genomes of arthropods. Our analyses reveal that Torso, Trunk and PTTH are evolutionarily labile components of the TAC with multiple individual or combined losses occurring in the arthropod lineages leading to and within the insects. These losses are often correlated, with both ligands and receptor missing from the genome of the same species. We determine that the PTTH gene evolved in the common ancestor of Hemiptera and Holometabola, and is missing from the genomes of a number of species with experimentally demonstrated PTTH activity, implying another molecule may be involved in ecdysis in these species. In contrast, the torso-like gene is a common component of pancrustacean genomes.

The honeybee as a model insect for developmental genetics.

Honeybees are an important component of modern agricultural systems, and a fascinating and scientifically engrossing insect. Honeybees are not commonly used as model systems for understanding development in insects despite their importance in agriculture. Honeybee embryogenesis, while being superficially similar to Drosophila, is molecularly very different, especially in axis formation and sex determination. In later development, much of honeybee biology is modified by caste development, an as yet poorly understood, but excellent, system to study developmental plasticity. In adult stages, developmental plasticity of the ovaries, related to reproductive constraint exhibits another aspect of plasticity. Here they review the tools, current knowledge and opportunities in honeybee developmental biology, and provide an updated embryonic staging scheme to support future studies.

Striatal mRNA expression patterns underlying peak dose L-DOPA-induced dyskinesia in the 6-OHDA hemiparkinsonian rat.

L-DOPA is the primary pharmacological treatment for relief of the motor symptoms of Parkinson's disease (PD). With prolonged treatment (⩾5 years) the majority of patients will develop abnormal involuntary movements as a result of L-DOPA treatment, known as L-DOPA-induced dyskinesia. Understanding the underlying mechanisms of dyskinesia is a crucial step toward developing treatments for this debilitating side effect. We used the 6-hydroxydopamine (6-OHDA) rat model of PD treated with a three-week dosing regimen of L-DOPA plus the dopa decarboxylase inhibitor benserazide (4 mg/kg and 7.5 mg/kgs.c., respectively) to induce dyskinesia in 50% of individuals. We then used RNA-seq to investigate the differences in mRNA expression in the striatum of dyskinetic animals, non-dyskinetic animals, and untreated parkinsonian controls at the peak of dyskinesia expression, 60 min after L-DOPA administration. Overall, 255 genes were differentially expressed; with significant differences in mRNA expression observed between all three groups. In dyskinetic animals 129 genes were more highly expressed and 14 less highly expressed when compared with non-dyskinetic and untreated parkinsonian controls. In L-DOPA treated animals 42 genes were more highly expressed and 95 less highly expressed when compared with untreated parkinsonian controls. Gene set cluster analysis revealed an increase in expression of genes associated with the cytoskeleton and phosphoproteins in dyskinetic animals compared with non-dyskinetic animals, which is consistent with recent studies documenting an increase in synapses in dyskinetic animals. These genes may be potential targets for drugs to ameliorate L-DOPA-induced dyskinesia or as an adjunct treatment to prevent their occurrence.

Ionising radiation exposure in patients with circular frame treatment of distal tibial fractures.

Total radiation exposure accumulated during circular frame treatment of distal tibial fractures was quantified in 47 patients treated by a single surgeon from February 2007 until Oct 2010. The radiation exposures for all relevant radiology procedures for the distal tibial injury were included to estimate the radiation risk to the patient. The median time of treatment in the frame was 169 days (range 105-368 days). Patients underwent a median of 13 sets of plain radiographs; at least one intra operative exposure and 16 patients underwent CT scanning. The median total effective dose per patient from time of injury to discharge was 0.025mSv (interquartile range 0.013-0.162 and minimum to maximum 0.01-0.53). The only variable shown to be an independent predictor of cumulative radiation dose on multivariate analysis was the use of CT scanning. This was associated with a 13-fold increase in overall exposure. Radiation exposure during treatment of distal tibial fractures with a circular frame in this group was well within accepted safe limits. The fact that use of CT was the only significant predictor of overall exposure serves as a reminder to individually assess the risk and utility of radiological investigations on an individual basis. This is consistent with the UK legal requirements for justification of all X-ray imaging, as set out in the Ionising Radiation (Medical Exposure) Regulations 2000 [1].

The importance of early life in childhood obesity and related diseases: a report from the 2014 Gravida Strategic Summit.

Obesity and its related non-communicable diseases (NCDs), such as type 2 diabetes, heart disease and cancer, impose huge burdens on society, particularly the healthcare system. Until recently, public health and policy were primarily focused on secondary prevention and treatment of NCDs. However, epidemiological and experimental evidence indicates that early-life exposures influence the risk of childhood obesity and related diseases later in life, and has now focused attention on the health of both mother and child. During pregnancy and the early neonatal period, individuals respond to their environment by establishing anatomical, physiological and biochemical trajectories that shape their future health. This period of developmental plasticity provides an early window of opportunity to mitigate the environmental insults that may increase an individual's sensitivity to, or risk of, developing obesity or related diseases later in life. Although much investigation has already occurred in the area of Developmental Origins of Health and Disease research, the science itself is still in its infancy. It remains for researchers to tackle the important outstanding questions and translate their knowledge into workable solutions for the public good. The challenge, however, is to decide which areas to focus on. With these opportunities and challenges in mind, the 2014 Gravida Summit convened to examine how its early-life research program can determine which areas of research into mechanisms, biomarkers and interventions could contribute to the international research strategy to fight childhood obesity and its related diseases.

Identification of reference genes for RT-qPCR in ovine mammary tissue during late pregnancy and lactation and in response to maternal nutritional programming.

The mammary gland is a complex tissue consisting of multiple cell types which, over the lifetime of an animal, go through repeated cycles of development associated with pregnancy, lactation and involution. The mammary gland is also known to be sensitive to maternal programming by environmental stimuli such as nutrition. The molecular basis of these adaptations is of significant interest, but requires robust methods to measure gene expression. Reverse-transcription quantitative PCR (RT-qPCR) is commonly used to measure gene expression, and is currently the method of choice for validating genome-wide expression studies. RT-qPCR requires the selection of reference genes that are stably expressed over physiological states and treatments. In this study we identify suitable reference genes to normalize RT-qPCR data for the ovine mammary gland in two physiological states; late pregnancy and lactation. Biopsies were collected from offspring of ewes that had been subjected to different nutritional paradigms during pregnancy to examine effects of maternal programming on the mammary gland of the offspring. We evaluated eight candidate reference genes and found that two reference genes (PRPF3 and CUL1) are required for normalising RT-qPCR data from pooled RNA samples, but five reference genes are required for analyzing gene expression in individual animals (SENP2, EIF6, MRPL39, ATP1A1, CUL1). Using these stable reference genes, we showed that TET1, a key regulator of DNA methylation, is responsive to maternal programming and physiological state. The identification of these novel reference genes will be of utility to future studies of gene expression in the ovine mammary gland.

Comprehensive survey of developmental genes in the pea aphid, Acyrthosiphon pisum: frequent lineage-specific duplications and losses of developmental genes.

Aphids exhibit unique attributes, such as polyphenisms and specialized cells to house endosymbionts, that make them an interesting system for studies at the interface of ecology, evolution and development. Here we present a comprehensive characterization of the developmental genes in the pea aphid, Acyrthosiphon pisum, and compare our results to other sequenced insects. We investigated genes involved in fundamental developmental processes such as establishment of the body plan and organogenesis, focusing on transcription factors and components of signalling pathways. We found that most developmental genes were well conserved in the pea aphid, although many lineage-specific gene duplications and gene losses have occurred in several gene families. In particular, genetic components of transforming growth factor beta (TGFbeta) Wnt, JAK/STAT (Janus kinase/signal transducer and activator of transcription) and EGF (Epidermal Growth Factor) pathways appear to have been significantly modified in the pea aphid.

Using underwater cameras to assess the effects of snorkeler and SCUBA diver presence on coral reef fish abundance, family richness, and species composition.

The results of underwater visual fish censuses (UVC) could be affected by fish changing their behavior in response to the snorkeler or diver conducting the survey. We used an underwater video camera to assess how fish abundance, family richness, and community composition were affected by the presence of snorkelers (n = 12) and self-contained underwater breathing apparatus (SCUBA) divers (n = 6) on a coral reef in Thailand. The total number of families, abundance of some fish families, and overall species composition showed significant differences before and during snorkeling disturbances. We did not detect significant and consistent changes to these parameters in the presence of a SCUBA diver; however, this could be a result of lower statistical power. We suggest that the use of a stationary video camera may help cross-check data that is collected through UVC to assess the true family composition and document the presence of rare and easily disturbed species.

The importance of supratidal habitats for wintering shorebirds and the potential impacts of shrimp aquaculture.

Intensive black tiger shrimp (Penaeus monodon) aquaculture ponds have replaced significant areas of coastal wetlands throughout tropical Asia. Few studies have assessed potential impacts on avian foraging habitats. At Khao Sam Roi Yod National Park, Thailand, seminatural wetlands have been converted to either shrimp ponds or to salinization ponds that provide saline water for shrimp aquaculture. Although shorebirds cannot feed in aquaculture ponds, hypersaline ponds can provide productive foraging areas. Thus, the overall impact of the shrimp industry on shorebirds depends partly on the relative quality of the salt ponds compared to seminatural wetlands. In this study, we examined wintering shorebird use of tidal (N = 5 sites) and supratidal areas (four wetland sites, four salt pond sites) and compared the shorebird community (14 species), prey availability, profitability, and disturbance rates between wetlands and salt ponds. Two shorebird species fed in higher densities in wetlands, whereas seven species were more abundant in salt ponds. Large juvenile fish and dragonfly larvae were more abundant in wetlands, whereas there were more small Chironomid midge and fly larvae in salt ponds. We conclude that salt ponds might provide higher-quality foraging habitats compared to wetlands for small shorebirds species because of the abundance of small larvae. However, the shrimp aquaculture industry reduces habitat availability for shorebirds feeding on larger prey. This study demonstrates a comprehensive, multispecies approach to assess the impacts of a large-scale change in coastal habitats for wintering shorebirds.

Early embryo patterning in the grasshopper, Schistocerca gregaria: wingless, decapentaplegic and caudal expression.

Although the molecular pathways that pattern the early embryo of Drosophila melanogaster are well understood, how these pathways differ in other types of insect embryo remains largely unknown. We have examined the expression of three markers of early patterning in the embryo of the African plague locust Schistocerca gregaria, an orthopteran insect that displays a mode of embryogenesis very different from that of Drosophila. Transcripts of the caudal gene are expressed maternally and are present in all cells that aggregate to form the early embryonic rudiment. First signs of a posterior-to-anterior gradient in the levels of caudal transcript appear in the early heart-stage embryo, shortly before gastrulation. This gradient rapidly resolves to a defined expression domain marking segment A11. The decapentaplegic (dpp) gene, which encodes a transforming growth factor beta family ligand, is first expressed in a circle of cells that delimit the margins of the embryonic primordium, where embryonic and extra-embryonic tissues abut. Patterned transcription of wingless reveals that the first segments are delineated in the Schistocerca embryo substantially earlier than previously thought, at least 14-16 hours before the onset of engrailed expression. By the late heart-stage, gnathal and thoracic segments are all defined. Thus, with respect to the molecular patterning of segments, the short germ Schistocerca embryo differs little from intermediate germ embryos. The expression of these marker genes suggests that embryonic pattern formation in the grasshopper occurs as cells move together to form the blastodisc.

New blast weapons.

Over the last decade a large number of weapon systems have appeared that use blast as their primary damage mechanism. This is a notable trend; until recently very few warheads relied on blast as their primary output. Most warheads in service use explosives to drive metal such as fragments and shaped charge jets to engage targets. New technologies are now being integrated into warheads that claim to have enhanced blast performance. Blast weapons could have been designed to fill a gap in capability; they are generally used for the attack of 'soft' targets including personnel, both in the open and within protective structures. With the increased number and range of these weapons, it is likely that UK forces will have to face them in future conflicts. This paper briefly describes fuel-air explosive blast weapons and reviews a range of enhanced blast weapons that have been developed recently. The paper concludes with a brief discussion on the reasons why enhanced blast technologies may be proliferating and how this could affect the Defence Medical Services.

dTcf antagonises Wingless signalling during the development and patterning of the wing in Drosophila.

Members of the Tcf family of HMG box-containing transcriptional regulators mediate Wnt signalling in the nucleus. Current models suggest that in the absence of Wnt signalling, Tcf interacts with the repressor protein Groucho and suppresses the expression of Wnt targets. Wnt signalling leads to increases in the level of cytoplasmic beta catenin, which enters the nucleus, displaces Tcf from Groucho and leads to transcriptional activation. In order to test this model we have studied the effects of Drosophila Tcf (dTcf) on signalling by Wingless, a Drosophila member of the Wnt family. We show that overexpression of wild-type dTcf during the development and patterning of the wing antagonises Wingless signalling. Furthermore, increases in the concentration of Armadillo, the Drosophila homologue of beta catenin, do not appear to be sufficient to trigger the change from antagonism to activation. This leads us to suggest that the inactivation of the repressive activity of dTcf requires the activity of Wingless in a manner that is independent of Armadillo. We observe that a Groucho molecule devoid of the WD40 repeats can interact with dTcf and acts as a dominant repressor of Wingless signalling in vivo and in vitro. Coexpression of this molecule with dTcf however, does not lead to enhancement of the repressive effects of dTcf alone. This observation suggests that repression by dTcf might not simply be mediated by an interaction with Groucho but that dTcf may have an intrinsic repressive activity that has to be antagonised by Wingless signalling.

A role for Fringe in segment morphogenesis but not segment formation in the grasshopper, Schistocerca gregaria.

Studies of somitogenesis in vertebrates have identified a number of genes that are regulated by a periodic oscillator that patterns the pre-somitic mesoderm. One of these genes, hairy, is homologous to a Drosophila segmentation gene that also shows periodic spatial expression. This, and the periodic expression of a zebrafish homologue of hairy during somitogenesis, has suggested that insect segmentation and vertebrate somitogenesis may use similar molecular mechanisms and possibly share a common origin. In chicks and mice expression of the lunatic fringe gene also oscillates in the presomitic mesoderm. Fringe encodes an extracellular protein that regulates Notch signalling. This, and the finding that mutations in Notch or its ligands disrupt somite patterning, suggests that Notch signalling plays an important role in vertebrate somitogenesis. Although Notch signalling is not known to play a role in the formation of segments in Drosophila, we reasoned that it might do so in other insects such as the grasshopper, where segment boundaries form between cells, not between syncytial nuclei as they do in Drosophila. Here we report the cloning of a single fringe gene from the grasshopper Schistocerca. We show that it is not detectably expressed in the forming trunk segments of the embryo until after segment boundaries have formed. We conclude that fringe is not part of the mechanism that makes segments in Schistocerca. Thereafter it is expressed in a pattern which shows that it is a downstream target of the segmentation machinery and suggests that it may play a role in segment morphogenesis. Like its Drosophila counterpart, Schistocerca fringe is also expressed in the eye, in rings in the legs, and during oogenesis, in follicle cells.

Maternal expression and early zygotic regulation of the Hox3/zen gene in the grasshopper Schistocerca gregaria.

In insects, a key step in the early patterning of the egg is to distinguish the primordium of the embryo proper from those regions that will form extra-embryonic membranes. In Drosophila, where these processes are well understood, the structure of the extra-embryonic membranes is highly derived. The distinct amnion and serosa typical of lower insects is replaced by a single, fused, and much reduced membrane, the amnioserosa, which never secretes an embryonic cuticle. We have used the Zen gene as a marker to study the formation of the extra-embryonic membranes, and other aspects of early embryonic patterning, in the grasshopper Schistocerca gregaria (African Plague Locust). Zen genes are derived from Hox genes, but in Drosophila they appear to have lost any role in patterning the A/P axis of the embryo; instead, they are involved in D/V patterning and the specification of the extra-embryonic membranes. We show that the Schistocerca zen gene is expressed during embryogenesis in three distinct phases. The first of these is during cleavage, when Sgzen is transiently expressed in all energids that reach the cell surface. The second phase of expression initiates in a ring of "necklace cells" that surround the forming embryo, and demarcate the boundary between the amnion and serosa. This leads to expression throughout the serosa. The final phase of expression is in the amnion, after this has separated from the serosa. This complex pattern implies that the role of Sgzen in Schistocerca is not limited solely to the specification of cell identity in the extra-embryonic membranes. We also report that the Schistocerca zen gene is expressed maternally, unlike its Drosophila and Tribolium counterparts. A distinct maternal transcript, and maternal Zen protein, accumulate in the developing oocyte from early post-meiotic stages. They remain uniformly distributed in the oocyte cytoplasm until late vitellogenic stages, when the protein and RNA become somewhat concentrated at the egg cortex and in the posterior polar cap of the oocyte, probably by passive exclusion from the yolk. The cytoplasmic localization of Sgzen protein in the oocyte, and at some stages during embryogenesis, implies that nuclear exclusion of this transcription factor is specifically controlled.

Developmental evolution: Axial patterning in insects.

The Drosophila bicoid gene is well known for encoding a protein that forms a morphogenetic gradient with a key role in anterior patterning of the fruitfly embryo. Recent results suggest the evolution of bicoid might have involved dramatic changes in function - essentially the invention of a new regulatory protein.