Committee experiences of using formal consensus in healthcare guidelines: a longitudinal qualitative study.

BACKGROUND: This feasibility study has the primary aim of capturing and comparing participant expectations and experiences of using a formal consensus method (FCM) and to explore whether these views change following participation within a guideline committee where FCM are used. METHODS: Twelve healthcare committee members and associated technical team members participated in semi-structured qualitative interviews before and after using FCM during guideline committee meetings. Interviews also focused on past experiences and expectations of informal consensus methods. RESULTS: Participants said formal consensus included a greater range of evidence. They described positive reactions and found it a useful way to encourage involvement by balancing group power dynamics. Group discussion time was identified as important to clarify ideas, supported by good group chairing. However, participants reported that undertaking FCM required additional resources and suggested targeting its use for low quality evidence, limited committee expertise, or where the evidence is controversial. CONCLUSIONS: FCM is an acceptable alternative to informal consensus methods that has qualities specifically helpful to healthcare guidelines such as encouraging participation, inclusivity of a broad range of evidence, and managing group dynamics. More research is required to better understand when using formal consensus is most appropriate and effective.

A demonstration of using formal consensus methods within guideline development; a case study.

BACKGROUND: Recommendations within guidelines are developed by synthesising the best available evidence; when limited evidence is identified recommendations are generally based on informal consensus. However, there are potential biases in group decision making, and formal consensus methods may help reduce these. METHODS: We conducted a case study using formal consensus, to develop one set of recommendations within the Neonatal Parenteral Nutrition guideline being produced for the National Institute for Health and Care Excellence. Statements were generated through identification of published guidelines on several topics relating to neonatal parenteral nutrition. Ten high quality guidelines were included, and 28 statements were generated; these statements were rated by the committee via two rounds of voting. The statements which resulted in agreement were then used to develop the recommendations. RESULTS: The approach was systematic and provided transparency. Additionally, a number of lessons were learnt; including the value of selecting the appropriate topic, giving adequate time to the process, and ensuring methodologies are understood by the committee for their value and relevance. CONCLUSION: Formal consensus is a valuable option for use within guideline development when specific criteria are met. The approach provides transparent methodology, ensuring clarity on how recommendations are developed.

The deposition of metal nanoparticles on carbon surfaces: the role of specific functional groups.

The enormous complexity of a typical heterogeneous catalyst makes understanding the development and properties of any active nanoparticles present extremely challenging. In the case of carbon based catalysts that difficulty is compounded by the variability of the carbon powders used. We have previously developed a strategy that addresses these problems by mimicking the catalyst preparation conditions very closely but using highly ordered pyrolytic graphite crystals (HOPG) as a model surface. This enables us to examine the effects of specific functional groups on nanoparticle formation. We report here an extension of our work characterising functional groups on the HOPG surface, using XPS and AFM to explore the deposition of gold from aqueous solution onto HOPG surfaces treated in a variety of ways to alter the surface functionality. The structure and oxidation state of the resulting nanoparticles depend critically on the nature of the functional groups present and offers some insight into the development of catalysts based on these materials. Hydroxyls are identified as key functional species, reducing gold ions to their metallic state whilst being oxidised themselves to carbonyls. Carbonyls meanwhile promote the nucleation of Au3+, creating a network of islands at the HOPG surface. The results have relevance not only to catalysts using activated carbons but also the new generation of materials based on graphene and carbon nanotubes.

Early first trimester uteroplacental flow and the progressive disintegration of spiral artery plugs: new insights from contrast-enhanced ultrasound and tissue histopathology.

STUDY QUESTION: Does the use of a vascular contrast agent facilitate earlier detection of maternal flow to the placental intervillous space (IVS) in the first trimester of pregnancy? SUMMARY ANSWER: Microvascular filling of the IVS was demonstrated by contrast-enhanced ultrasound from 6 weeks of gestation onwards, earlier than previously believed. WHAT IS KNOWN ALREADY: During placental establishment and remodeling of maternal spiral arteries, endovascular trophoblast cells invade and accumulate in the lumen of these vessels to form 'trophoblast plugs'. Prior evidence from morphological and Doppler ultrasound studies has been conflicting as to whether the spiral arteries are completely plugged, preventing maternal blood flow to the IVS until late in the first trimester. STUDY DESIGN, SIZE, DURATION: Uteroplacental flow was examined across the first trimester in human subjects given an intravenous infusion of lipid-shelled octofluoropropane microbubbles with ultrasound measurement of destruction and replenishment kinetics. We also performed a comprehensive histopathological correlation using two separately archived uteroplacental tissue collections to evaluate the degree of spiral artery plugging and evaluate remodeling of the upstream myometrial radial and arcurate arteries. PARTICIPANTS/MATERIALS, SETTING, METHODS: Pregnant women (n = 34) were recruited in the first trimester (range: 6+3 to 13+6 weeks gestation) for contrast-enhanced ultrasound studies with destruction-replenishment analysis of signal intensity for assessment of microvascular flux rate. Histological samples from archived in situ (Boyd Collection, n = 11) and fresh first, second, and third trimester decidual and post-hysterectomy uterine specimens (n = 16) were evaluated by immunohistochemistry (using markers of epithelial, endothelial and T-cells, as well as cell adhesion and proliferation) and ultrastructural analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Contrast agent entry into the IVS was visualized as early as 6+3 weeks of gestation with some variability in microvascular flux rate noted in the 6-7+6 week samples. Spiral artery plug canalization was observed from 7 weeks with progressive disintegration thereafter. Of note, microvascular flux rate did not progressively increase until 13 weeks, which suggests that resistance to maternal flow in the early placenta may be mediated more proximally by myometrial radial arteries that begin remodeling at the end of the first trimester. LIMITATIONS REASONS FOR CAUTION: Gestational age was determined by crown-rump length measurements obtained by transvaginal ultrasound on the day of contrast-enhanced imaging studies, which may explain the variability in the earliest gestational age samples due to the margin of error in this type of measurement. WIDER IMPLICATIONS OF THE FINDINGS: Our comprehensive in situ histological analysis, in combination with the use of an in vivo imaging modality that has the sensitivity to permit visualization of microvascular filling, has allowed us to reveal new evidence in support of increasing blood flow to the IVS from 6 weeks of gestation. Histologic review suggested the mechanism may be blood flow through capillary-sized channels that form through the loosely cohesive 'plugs' by 7 weeks gestation. However, spiral artery remodeling on its own did not appear to explain why there is significantly more blood flow at 13 weeks gestation. Histologic studies suggest it may be related to radial artery remodeling, which begins at the end of the first trimester. STUDY FUNDING/COMPETING INTEREST(S): This project was supported by the Oregon Health and Science University Knight Cardiovascular Institute, Center for Developmental Health and the Struble Foundation. There are no competing interests.

Functional imaging of the nonhuman primate Placenta with endogenous blood oxygen level-dependent contrast.

PURPOSE: To characterize spatial patterns of T2* in the placenta of the rhesus macaque (Macaca mulatta), to correlate these patterns with placental perfusion determined using dynamic contrast-enhanced MRI (DCE-MRI), and to evaluate the potential for using the blood oxygen level-dependent effect to quantify placental perfusion without the use of exogenous contrast reagent. METHODS: MRI was performed on three pregnant rhesus macaques at gestational day 110. Multiecho spoiled gradient echo measurements were used to compute maps of T2*. Spatial maxima in these maps were compared with foci of early enhancement determined by DCE-MRI. RESULTS: Local maxima in T2* maps were strongly correlated with spiral arteries identified by DCE-MRI, with mean spatial separations ranging from 2.34 to 6.11 mm in the three animals studied. Spatial patterns of R2* ( = 1/ T2*) within individual placental lobules can be quantitatively analyzed using a simple model to estimate fetal arterial oxyhemoglobin concentration [Hbo,f] and a parameter viPS/Φ, reflecting oxygen transport to the fetus. Estimated mean values of [Hbo,f] ranged from 4.25 mM to 4.46 mM, whereas viPS/Φ ranged from 2.80 × 105 cm-3 to 1.61 × 106 cm-3 . CONCLUSIONS: Maternal spiral arteries show strong spatial correlation with foci of extended T2* observed in the primate placenta. A simple model of oxygen transport accurately describes the spatial dependence of R2* within placental lobules and enables assessment of placental function and oxygenation without requiring administration of an exogenous contrast reagent. Magn Reson Med 76:1551-1562, 2016. © 2015 International Society for Magnetic Resonance in Medicine.

Generation and analysis of random point mutations in an antibody CDR2 sequence: many mutated antibodies lose their ability to bind antigen.

We have investigated the impact of mutations on the binding functions of the phosphocholine (PC)-specific T15 antibody in the absence of antigen selection pressure. The H chain complementarity determining region 2 (CDR2) sequence of T15 antibody was saturated with point mutations by in vitro random mutagenesis. From the mutant library, 289 clones were screened by direct DNA sequencing. The point mutations generated by this method were randomly distributed throughout the CDR2 region and included all kinds of substitutions. 46 unique mutant antibodies, containing one to four point mutations each, were expressed in SP2/0 myeloma cells. Functional analysis on these antibodies has provided insights into several aspects of somatic mutation. (a) The majority (26/46) of mutant antibodies either lost (20/46) or had reduced (6/46) ability to bind PC-protein conjugates or R36a, a PC-expressing strain of Streptococcus pneumoniae. In contrast, none of the mutant antibodies displayed increased binding for these PC antigens. Taken together with calculations of destructive mutations elsewhere in the V region, the data suggest that somatic mutation may cause extensive wastage among B cells during clonal expansion after antigen stimulation. (b) The frequency of binding-loss mutants increased sharply when a second mutation was introduced into the CDR2 sequence; it appears that, in some cases, two or more mutations are needed to destroy binding. (c) The mutant antibodies were tested for their reactivity to 11 non-PC antigens as well as to three PC analogues. None of the mutants gained new reactivity or changed their ability to discriminate structural analogues, supporting the notion that the major role of somatic mutation is to increase or decrease affinity rather than to create new specificities. (d) Mutations in at least five different positions in CDR2 were deleterious, suggesting that these residues may be essential for antigen binding. Three of these positions are novel in that they had not been identified to be important for binding PC by previous crystallographic analysis. (e) Introduction of mutations into two highly conserved residues in CDR2 did not alter the overall conformation of the V region as judged by antiidiotypic analysis, and, in some cases, did not affect the antigen binding function. The results thus indicate that even nonconservative substitutions of invariant residues need not be deleterious, suggesting that their conservation may be due to reasons other than maintaining antibody structure or specificity.

Children and television watching: a qualitative study of New Zealand parents' perceptions and views.

BACKGROUND: Television (TV) viewing is one of the most pervasive sedentary pursuits among children and adolescents. Research studies have shown that higher TV viewing hours are associated with a number of negative effects such as being overweight and obese, attention and behavioural problems, and impaired academic performance. Most interventions to reduce time spent watching TV have been school-based and little is known about the strategies that families use to control TV watching time. METHODS: Six focus groups with Maori, Pacific and non-Maori non-Pacific parents were conducted to examine New Zealand parents' perceptions of their children's TV watching. Focus groups explored attitudes towards TV viewing, strategies used to reduce viewing, and opinion on two different electronic monitors that can be used to restrict TV viewing. Focus group discussions were transcribed and a content analysis was conducted. RESULTS: Parents described TV as playing a dominant role in their family's lives, and highlighted several barriers to reducing children's TV viewing, such as parents not willing to reduce their own TV watching, a lack of safe alternatives to TV and the need to use TV as a babysitting tool. Limiting access to TV, making TV viewing a reward and finding alternative activities were current strategies parents employed to limit TV viewing; however, the barriers highlighted by parents make implementing such strategies difficult. Attitudes towards electronic monitor use to reduce TV viewing were mixed, but suggest further investigation of these devices is needed. CONCLUSIONS: Electronic devices that restrict the amount and content of TV viewing have some potential to support interventions and merit further investigation. It is imperative for interventions aimed at reducing TV viewing to consider the role TV plays within a family context, ensuring parental perceptions around the benefits and barriers of reducing TV are accounted for.

The safety and efficacy of neuromodulation using percutaneous electrical nerve stimulation for the management of trigeminal-mediated headshaking in 168 horses.

BACKGROUND: Early results from the use of neuromodulation by percutaneous electrical nerve stimulation for the management of trigeminal-mediated headshaking in horses were promising but lacked sufficient case numbers and long-term follow-up. The neuromodulatory procedure has since been established as EquiPENS™. OBJECTIVES: The aim of this study was to report long-term results from a larger number of cases and to investigate for predictors of outcome. STUDY DESIGN: Prospective case series using international, multi-centre data. METHODS: Eligible cases were horses with a veterinary diagnosis of trigeminal-mediated headshaking, which received EquiPENS™ neuromodulation at trained centres between August 2013 and November 2017. The standard protocol was an initial three-procedure course, with additional procedures should a horse go into remission but then relapse. Data collected included signalment, history, diagnostic tests performed, details of any complications, whether horses had gone into remission and the length of remission. RESULTS: Results were obtained from 168 horses, with 530 procedures. The complication rate was 8.8% of procedures. In all but one case, complications were mild and transient, without self-trauma. Remission of headshaking following the initial course occurred in 53% (72/136) of horses. Median length of time recorded in remission was 9.5 weeks (range 2 days to 156 weeks ongoing). Where signs recurred, most horses went back into remission following additional procedures, usually for longer than from the previous procedure. No predictors for outcome were determined. MAIN LIMITATIONS: No placebo or control group, owner-assessed results. CONCLUSIONS: EquiPENS™ neuromodulation can be an effective and safe treatment for the management of trigeminal-mediated headshaking in some horses. An increased understanding of neuromodulation could help optimise the technique. Advances in treatment for trigeminal-mediated headshaking will remain limited until there is a greater understanding of the aetiopathogenesis of the condition.

Effect of increasing maternal body mass index on oxidative and nitrative stress in the human placenta.

Maternal obesity is an increasing problem in obstetrics associated with adverse pregnancy outcomes and delivery complications. As an inflammatory state, where elevated levels of pro-inflammatory cytokines are found, obesity can lead to the increased incidence of oxidative and nitrative stress. These stresses may result in protein oxidation and protein nitration respectively, which are post- translational covalent modifications that can modify the structure and subsequently alter the function of a protein. The objective of this study was to examine whether placental oxidative and nitrative stress increase with increasing maternal body mass index. Placental tissue was collected from three groups of patients categorized as lean, overweight and obese. The presence of nitrotyrosine residues, a marker of nitrative stress, and antioxidant enzymes, as markers of oxidative stress, were assessed by immunohistochemistry, Western blot and ELISA. Protein carbonyl formation, a specific measure of protein oxidation, was measured by OxyBlot kit. Nitrotyrosine residues were increased in obese compared to lean and overweight groups although localization was unaltered across the three groups. Superoxide dismutase enzyme expression, localization and activity was unaltered between the groups. Protein carbonyl formation was greater in the lean compared to the overweight individuals. This study demonstrates that with increasing maternal body mass index there is an increase in placental nitrative stress. There does not appear to be a corresponding increase in oxidative stress and indeed we demonstrate some evidence of a decrease in oxidative effects in these placenta samples. Potentially the formation of peroxynitrite may be consuming reactive oxygen species and reducing oxidative stress. There may be a shift in the balance between nitrative and oxidative stress, which may be a protective mechanism for the placenta.

Metalloantibodies.

A metalloantibody has been constructed with a coordination site for metals in the antigen binding pocket. The Zn(II) binding site from carbonic anhydrase B was used as a model. Three histidine residues have been placed in the light chain complementarity determining regions of a single chain antibody molecule. In contrast to the native protein, the mutant displayed metal-dependent fluorescence-quenching behavior. This response was interpreted as evidence for metal binding in the three-histidine site with relative affinities in the order Cu(II) greater than Zn(II) greater than Cd(II). The presence of metal cofactors in immunoglobulins should facilitate antibody catalysis of redox and hydrolytic reactions.

Surface EMG analysis on normal subjects based on isometric voluntary contraction.

The objective of this study was to compute reference SEMG values for normal subjects of 13 parameters extracted in the time, frequency and bispectrum domain, from the Biceps Brachii (BB) muscle generated under isometric voluntary contraction (IVC). SEMG signals were recorded from 94 subjects for 5s at 10, 30, 50, 70 and 100% of maximum voluntary contraction (MVC). The Wilcoxon signed rank test was applied to detect significant differences or not at p<0.05 between force levels for each of the 13 parameters. The main findings of this study can be summarized as follows: (i) The time domain parameters turns per second and number of zero crossings per second increase significantly with force level. (ii) The power spectrum median frequency parameter decreases significantly with force level, whereas maximum power and total power increase significantly with force level. (iii) The bispectrum parameter, maximum amplitude, increases significantly with force level with the exception the transition from 30% to 50% MVC. Although, the tests for Gaussianity and linearity show no significant difference with force level, the SEMG signal exhibits a more Gaussian distribution with increase of force up to 70% MVC. The SEMG linearity test, which is a measure of how constant the bicoherence index is in the bi-frequency domain, shows that the signal's bicoherence index is less constant (hence, the signal is less linear) at 70% of MVC compared to 10, 30, 50 and 100% MVC. (iv) The time domain parameters have good correlation between them as well as, between each one of them and maximum and total power. The median frequency has a good (negative) correlation with the bispectrum peak amplitude. (v) No significant differences exist between values based on gender or age. The findings of this study can further be used for the assessment of subjects suffering with neuromuscular disorders, or in the rehabilitation laboratory for monitoring the elderly or the disabled, or in the occupational medicine laboratory.

Caudal compression of the infraorbital nerve: a novel surgical technique for treatment of idiopathic headshaking and assessment of its efficacy in 24 horses.

UNLABELLED: REASONS FOR DESIGNING AND REPORTING TECHNIQUE: Idiopathic headshaking has remarkable similarities to human neuropathic facial pain syndromes associated with post herpetic and trigeminal neuralgia. These derive from abnormal sensory function within the peripheral or central pathways of the trigeminal nerve (TgN). Limiting input from the TgN can be helpful in controlling the perception of pain. Rhizotomy of the infraorbital branch of the TgN as it emerges from the infraorbital canal has been reported but has a poor efficacy. A novel technique involves compression of the nerve at a more caudal location within the infraorbital canal and the technique requires validation. HYPOTHESIS: Caudal compression of the infraorbital nerve with platinum coils, performed in horses diagnosed with idiopathic headshaking, results in a decrease in clinical signs. METHODS: Caudal compression of the infraorbital nerve, using platinum embolisation coils, was performed under fluoroscopic guidance. Clinical records of 24 idiopathic headshakers that had undergone this procedure were reviewed. Follow-up information was obtained by telephone questionnaire with the owner or referring veterinary surgeon. RESULTS: All 24 horses had at least one surgical procedure. Median follow-up time was 6 months. There were 2 horses which had surgery 2 weeks before follow-up and these were excluded from the analysis of outcome. Following one surgery, 13/22 horses (59.0%) had a successful outcome. Of the 9 horses that did not improve, surgery was repeated in 6 cases. Two of these horses had a successful outcome. Overall, a successful outcome was obtained in 16/19 horses (84.2%). CONCLUSIONS: This surgical technique is likely to prevent input from the TgN at a more caudal location then the previously described infraorbital neurectomy. The technique requires refinement.

Protein nitration in placenta - functional significance.

Crucial roles of the placenta are disrupted in early and mid-trimester pregnancy loss, preeclampsia, eclampsia and intrauterine growth restriction. The pathophysiology of these disorders includes a relative hypoxia of the placenta, ischemia/reperfusion injury, an inflammatory response and oxidative stress. Reactive oxygen species including nitric oxide (NO), carbon monoxide and superoxide have been shown to participate in trophoblast invasion, regulation of placental vascular reactivity and other events. Superoxide, which regulates expression of redox sensitive genes, has been implicated in up-regulation of transcription factors, antioxidant production, angiogenesis, proliferation and matrix remodeling. When superoxide and nitric oxide are present in abundance, their interaction yields peroxynitrite a potent pro-oxidant, but also alters levels of nitric oxide, which in turn affect physiological functions. The peroxynitrite anion is extremely unstable thus evidence of its formation in vivo has been indirect via the occurrence of nitrated moieties including nitrated lipids and nitrotyrosine residues in proteins. Formation of 3-nitrotyrosine (protein nitration) is a "molecular fingerprint" of peroxynitrite formation. Protein nitration has been widely reported in a number of pathological states associated with inflammation but is reported to occur in normal physiology and is thought of as a prevalent, functionally relevant post-translational modification of proteins. Nitration of proteins can give either no effect, a gain or a loss of function. Nitration of a range of placental proteins is found in normal pregnancy but increased in pathologic pregnancies. Evidence is presented for nitration of placental signal transduction enzymes and transporters. The targets and extent of nitration of enzymes, receptors, transporters and structural proteins may markedly influence placental cellular function in both physiologic and pathologic settings.

Spectroscopic and kinetic study of the gas-phase CH3I-Cl and C2H5I-Cl adducts.

Time-resolved UV-visible absorption spectroscopy has been coupled with UV laser flash photolysis of Cl2/RI/N2/X mixtures (R = CH3 or C2H5; X = O2, NO, or NO2) to generate the RI-Cl radical adducts in the gas phase and study the spectroscopy and reaction kinetics of these species. Both adducts were found to absorb strongly over the wavelength range 310-500 nm. The spectra were very similar in wavelength dependence with lambda(max) approximately 315 nm for both adducts and sigma(max) = (3.5 +/- 1.2) x 10(-17) and (2.7 +/- 1.0) x 10(-17) cm(2) molecule(-1) (base e) for CH3I-Cl and C2H5I-Cl, respectively (uncertainties are estimates of accuracy at the 95% confidence level). Two weaker bands with lambda max approximately 350 and 420 nm were also observed. Over the wavelength range 405-500 nm, where adduct spectra are reported both in the literature and in this study, the absorption cross sections obtained in this study are a factor of approximately 4 lower than those reported previously [Enami et al. J. Phys. Chem. A 2005, 109, 1587 and 6066]. Reactions of RI-Cl with O2 were not observed, and our data suggest that upper limit rate coefficients for these reactions at 250 K are 1.0 x 10(-17) cm(3) molecule(-1) s(-1) for R = CH3 and 2.5 x 10(-17) cm(3) molecule(-1) s(-1) for R = C2H5. Their lack of reactivity with O2 suggests that RI-Cl adducts are unlikely to play a significant role in atmospheric chemistry. Possible reactions of RI-Cl with RI could not be confirmed or ruled out, although our data suggest that upper limit rate coefficients for these reactions at 250 K are 3 x 10(-13) cm(3) molecule(-1) s(-1) for R = CH3 and 5 x 10(-13) cm(3) molecule(-1) s(-1) for R = C2H5. Rate coefficients for CH3I-Cl reactions with CH3I-Cl (k9), NO (k22), and NO2 (k24), and C2H5I-Cl reactions with C2H5I-Cl (k14), NO (k23), and NO2 (k25) were measured at 250 K. In units of 10(-11) cm(3) molecule(-1) s(-1), the rate coefficients were found to be 2k9 = 35 +/- 12, k22 = 1.8 +/- 0.4, k24 = 3.3 +/- 0.6, 2k14 = 40 +/- 16, k23 = 1.8 +/- 0.3, and k25 = 4.0 +/- 0.9, where the uncertainties are estimates of accuracy at the 95% confidence level.

Prevalence of headshaking within the equine population in the UK.

REASON FOR PERFORMING STUDY: Headshaking in horses has been reported to be most commonly due to idiopathic neuropathic facial pain (trigeminal-mediated headshaking). The prevalence of headshaking in horses in the UK is unknown. OBJECTIVES: To estimate owner-reported prevalence of headshaking in horses in the UK and to report their case background and disease characteristics, as reported by owners. STUDY DESIGN: Cross-sectional web based owner questionnaire. METHODS: The questionnaire was advertised online via social media, horse forums, veterinary websites and equestrian magazines from 17th June 2016, until >1000 responses had been obtained. All UK horse owners were eligible to complete the questionnaire, however only one questionnaire could be completed per owner. RESULTS: The estimated prevalence of owner-reported headshaking in the sample population of horses (n = 1014), within the last year, was 4.6% (95% confidence interval 3.5-6.1), whereas 6.2% (95% confidence interval 4.9-7.9) of horses were reported by their owners to have shown signs of headshaking at any time-point since ownership. There was no association of sex or breed. Nineteen percent of headshaking horses were reported to show headshaking at rest. Fewer than one-third (30.2%, n = 19) of headshaking horses had been examined by a veterinarian for headshaking. Of horses seen by a veterinarian, the cause for headshaking remained unknown in the majority of cases (57.9% responses) and trigeminal-mediated headshaking was reported as a diagnosis in just one case. MAIN LIMITATIONS: The accuracy in data reporting by horse owners was not verified in this study. There may be a potential for bias towards over-reporting due to the nature of survey participation. CONCLUSIONS: Within this sample, owner-reported prevalence of signs of headshaking within the last year, in horses in the UK was 4.6%. Over two-thirds of owners of headshaking horses did not seek veterinary intervention for headshaking. Trigeminal-mediated headshaking was rarely reported by owners as a diagnosis.

Purinergic receptor expression and activation in first trimester and term human placenta.

Intracellular calcium concentration ([Ca(2+)](i)) is an important signalling molecule in the human placenta and regulation of [Ca(2+)](i) must be tightly controlled to ensure normal cell function and in order to meet the changing demand for calcium with increased fetal growth over gestation. Little is known about the receptors and mechanisms involved in intracellular calcium signalling in the human placenta but in isolated cytotrophoblast cells members of the P2 purinergic receptor family have been shown to mediate an ATP-stimulated rise in [Ca(2+)](i). In this study we examined activation and expression of several of the purinergic receptor subtypes in human placental villous fragments at two stages of gestation, first trimester and term. We demonstrate mRNA and protein expression of the P2X(4), P2X(7) and P2Y(2) subtypes but found no evidence of P2Y(4) protein in the placenta. Using fluorescent calcium imaging we demonstrate that 300 microM ATP, 450 microM UTP and 300 microM BzATP significantly elevate [Ca(2+)](i) in villous fragments with a significant increase in agonist-induced response seen in the term compared to the first trimester fragments (ATP, P<0.0001; UTP, P=0.018; BzATP, P=0.015). The roles of the purinergic receptors within the human placenta are not known but it seems likely for this study that calcium handling through these receptors is altered with advancing gestation. This may be due to the need to meet increased fetal Ca(2+) requirements due to growth or as a secondary function to alterations in placental [Ca(2+)](i) signalling.

Post-Translational Modifications of the P2X(4) purinergic receptor subtype in the human placenta are altered in preeclampsia.

P2X(4) receptors are activated by extracellular ATP to raise intracellular calcium, thus altering cell signalling. ATP release occurs under pathophysiological, stress and adverse cell conditions; these are all increased in preeclampsia. Although P2X(4) is abundantly expressed in normal placenta neither the differences in the amount of protein nor its post-translational modifications have been studied in placentae from pregnancies complicated by preeclampsia. Thus we examined P2X(4) protein expression, localization and post-translational modifications in normotensive controls, term and preterm preeclamptic placentae. Densitometric analysis of Western blots showed a significant increase in P2X(4) protein expression in both term (p=0.002) and preterm preeclamptic (p=0.0008) placental samples compared to normotensive controls however the tissue localization of this receptor subtype was unaltered across the groups. Our data showed that P2X(4) is a nitrated protein in the placenta and this nitration is upregulated in preterm preeclamptic placenta compared to normotensive controls (p=0.03). We also demonstrated that P2X(4) is heavily glycosylated in the placenta by deglycosylation with PNGase F which reduced the protein product size by 23 kDa. We propose that P2X(4) acts within the syncytiotrophoblast to alter intracellular calcium and subsequent signalling pathways thereby restoring placental cell homeostasis following ATP-induced changes during pathophysiological conditions such as preeclampsia. We also propose that the post-translational modifications of nitration and glycosylation are required for the normal functioning of P2X(4).

What impact have NICE guidelines had on the trends of hip arthroplasty since their publication? The results from the Trent Regional Arthroplasty Study between 1990 and 2005.

The National Institute for Clinical Excellence (NICE) published the guidelines on the selection of prostheses for primary hip replacement in 2000. They supported the use of cemented hip prostheses to the exclusion of uncemented and hybrid implants. The information from the Trent (and Wales) Regional Arthroplasty Study has been examined to identify retrospectively the types of hip prostheses used between 1990 and 2005, and to assess the impact that the guidelines have had on orthopaedic practice. The results show that the publication of the NICE guidelines has had little impact on clinical practice, with the use of uncemented prostheses increasing from 6.7% (137) in 2001 to 19.2% (632) in 2005. The use of hybrid prostheses has more than doubled from 8.8% (181) to 22% (722) of all hips implanted in the same period. The recommendations made by NICE are not being followed, which calls into question their value.

A 15-year follow-up study of 4606 primary total knee replacements.

This is a 15-year follow-up observational study of 4390 patients with 4606 primary total knee replacements (TKRs) implanted in the Trent health region between 1990 and 1992. The operations were performed in 21 hospitals, including both district general and teaching hospitals, with 77 different surgeons as named consultant. The main objective was to analyse the survival of the patients and of the prostheses, and to evaluate what impact different variables have on survival. In addition, the 1480 patients (33.7%) (1556 TKRs) alive at 15 years following operation were sent a self-administered questionnaire which examined their level of satisfaction, of pain, and their quality of life at 15 years. Completed responses were received from 912 TKRs (58.6%). Three survival curves were constructed: a best-case scenario based on the patients entered into the life tables, another included failures not reported in the revision database, and a third worst-case scenario based on all patients lost to follow-up presumed to have had a failed primary TKR. In the best-case scenario survival at 15 years was 92.2%, and in the worst-case scenario was 81.1%. Survival was significantly increased in women and older patients (Mantel-Cox log-rank test, p < 0.005 and p < 0.001, respectively). Revision as a result of infection was required in 40 TKRs (18.8%) representing 0.87% of the original cohort. The limited information available from the questionnaire indicated that satisfaction was less frequent among men, patients with osteoarthritis and those who required revision (chi-squared test, p < 0.05, p < 0.05 and p < 0.0001, respectively). With regard to pain, older patients, females and patients who still had their primary replacement in place at 15 years, reported the least pain (chi-squared test for trends, p < 0.0005, p < 0.005 and p < 0.0001, respectively). The reported quality of life was not affected by any variable.

Anatomical variations in vastus medialis obliquus and its implications in minimally-invasive total knee replacement. An MRI study.

The emergence of minimally-invasive total knee replacement (TKR) has led to the refinement of several surgical approaches, including the quadriceps-sparing and sub-vastus. There is some disagreement as to the precise definition of the term 'minimally-invasive', especially in regard to the preservation of vastus medialis obliquus (VMO). It is known that the termination of VMO is variable and may make these approaches difficult. We have attempted to assess the factors influencing the insertion of VMO and the impact which they have on the approach for TKR. The MR scans of 198 knees were examined to assess the variation in the insertion of VMO in relation to the patella and the effect of variables such as age, gender and the presence of concurrent osteoarthritis of the knee on the insertion. Our findings showed that both age and the presence of osteoarthritis were contributing factors to changes in the level of insertion of VMO. Therefore, not all capsular incisions which extend proximal to the midpole of the patella will violate the quadriceps tendon.