Optimising adjacent membrane segmentation and parameterisation in multicellular aggregates by piecewise active contours.

In fluorescence microscopy imaging, the segmentation of adjacent cell membranes within cell aggregates, multicellular samples, tissue, organs, or whole organisms remains a challenging task. The lipid bilayer is a very thin membrane when compared to the wavelength of photons in the visual spectra. Fluorescent molecules or proteins used for labelling membranes provide a limited signal intensity, and light scattering in combination with sample dynamics during in vivo imaging lead to poor or ambivalent signal patterns that hinder precise localisation of the membrane sheets. In the proximity of cells, membranes approach and distance each other. Here, the presence of membrane protrusions such as blebs; filopodia and lamellipodia; microvilli; or membrane vesicle trafficking, lead to a plurality of signal patterns, and the accurate localisation of two adjacent membranes becomes difficult. Several computational methods for membrane segmentation have been introduced. However, few of them specifically consider the accurate detection of adjacent membranes. In this article we present ALPACA (ALgorithm for Piecewise Adjacent Contour Adjustment), a novel method based on 2D piecewise parametric active contours that allows: (i) a definition of proximity for adjacent contours, (ii) a precise detection of adjacent, nonadjacent, and overlapping contour sections, (iii) the definition of a polyline for an optimised shared contour within adjacent sections and (iv) a solution for connecting adjacent and nonadjacent sections under the constraint of preserving the inherent cell morphology. We show that ALPACA leads to a precise quantification of adjacent and nonadjacent membrane zones in regular hexagons and live image sequences of cells of the parapineal organ during zebrafish embryo development. The algorithm detects and corrects adjacent, nonadjacent, and overlapping contour sections within a selected adjacency distance d, calculates shared contour sections for neighbouring cells with minimum alterations of the contour characteristics, and presents piecewise active contour solutions, preserving the contour shape and the overall cell morphology. ALPACA quantifies adjacent contours and can improve the meshing of 3D surfaces, the determination of forces, or tracking of contours in combination with previously published algorithms. We discuss pitfalls, strengths, and limits of our approach, and present a guideline to take the best decision for varying experimental conditions for in vivo microscopy.

Misclassification of stunting, underweight and wasting in children 0-5 years of South Asian and Dutch descent: ethnic-specific v. WHO criteria.

OBJECTIVE: Several authors have questioned the suitability of WHO Child Growth Standards (WHO-CGS) for all ethnic groups. The aim of this study was to identify potential misclassification of stunting, underweight and wasting in children of Surinamese Asian Indian, South Asian (Pakistan/India) and Dutch descent. DESIGN: A series of routine cross-sectional measurements, collected 2012-2015. South Asian-specific normative growth references for weight-for-age and weight-for-length/height were constructed using the LMS method based on historic growth data of Surinamese Asian Indians born between 1974 and 1976. WHO-CGS and ethnic-specific references were applied to calculate z-scores and prevalence of stunting, underweight and wasting. SETTING: Youth HealthCare, providing periodical preventive health check-ups. PARTICIPANTS: 11 935 children aged 0-5 years. RESULTS: Considerable deviations from WHO-CGS were found, with higher-than-expected stunting rates, especially in the first 6 months of life. Surinamese Asian Indian children showed stunting rates up to 16·0 % and high underweight and wasting over the whole age range (up to 7·2 and 6·7 %, respectively). Dutch children consistently had mean WHO-CGS z-scores 0·3-0·5 sd above the WHO baseline (>6 months). The application of ethnic-specific references showed low rates for all studied indicators, although South Asian children were taller and larger than their Surinamese Asian Indian counterparts. CONCLUSIONS: WHO-CGS misclassify a considerable proportion of children from all ethnic groups as stunted in the first 6 months of life. Underweight and wasting are considerably overestimated in Surinamese Asian Indian children. Ethnic-specific growth references are recommended for Surinamese Asian Indian and Dutch children. The considerable differences found between South Asian subpopulations requires further research.

Effect of neighbourhood socioeconomic status on overweight and obesity in children 2-15 years of different ethnic groups.

BACKGROUND: Studies on the influence of neighbourhood socioeconomic status (N-SES) on overweight and obesity rates in children from different ethnic backgrounds are scarce. This study investigated the differential effect of N-SES on overweight (including obesity) and obesity prevalence in different ethnic groups, and if N-SES explains ethnic differences in the prevalence of overweight and obesity. DESIGN: A population based study of 109 766 body mass index (BMI) measurements of 86 209 children 2-15 years of Dutch, Turkish, Moroccan and South Asian descent. BMI class was determined with The International Obesity Task Force, and South Asian specific BMI cut-offs. WHO BMI criteria were applied for reference purposes. The effect of N-SES on prevalence rates was studied with generalized linear mixed models. RESULTS: Neighbourhood SES was negatively associated with overweight and obesity. However, the effect of N-SES on overweight was stronger in Dutch children (OR 0.75, 95% CI 0.73-0.77) than in Turkish (OR 0.86, 95% CI 0.82-0.90), Moroccan (OR 0.91, 95% CI 0.86-0.97) and South Asian (OR 0.90, 95% CI 0.84-0.96) children. The influence of N-SES on obesity showed a similar pattern, except for Moroccan children in whom obesity prevalence remained stable over the whole N-SES range. At the same N-SES, overweight and obesity prevalence was significantly higher in Turkish, Moroccan and especially South Asian children compared with Dutch children. Adjusting for N-SES attenuated the ethnic differences. CONCLUSIONS: Neighbourhood SES was negatively associated with overweight and obesity rates in all ethnic groups, but only partly explained the ethnic differences in overweight and obesity prevalence.

Tracking of thinness and overweight in children of Dutch, Turkish, Moroccan and South Asian descent from 3 through 15 years of age: a historical cohort study.

BACKGROUND: Overweight is shown to track (= to maintain a relative position in a distribution) from childhood to adulthood, but is mostly studied in preobesogenic cohorts and in single ethnic groups. Little is known about tracking of thinness by ethnicity. OBJECTIVES: to determine (differences in) tracking of BMI (class) from 3 through 15 years and the prediction of BMI class at 13-15 years of age in contemporary Dutch, Turkish, Moroccan and South Asian children living in the Netherlands. METHODS: Historical cohort of 7625 children, born 1994-1997, with 24,376 measurements of BMI. BMI z-score and BMI class was analysed using universal criteria. South Asian children were also assessed using ethnic specific BMI criteria. Diagnostic odds ratios (OR) and test properties were calculated to estimate the ability of BMI class at 3-4 years to predict BMI class at 13-15 years. RESULTS: Tracking of thinness between 3 and 15 years was stronger than that of overweight, as indicated by a generally higher diagnostic OR. BMI trajectories between 3 and 15 years of age of thin, normal weight and overweight adolescents were, although significantly different, quite similarly shaped in children of Dutch, Turkish and Moroccan descent. The South Asian BMI trajectory deviated considerably from the other ethnic groups, but the differences disappeared when South Asian specific BMI criteria were applied. A substantial proportion of overweight developed between 5-10 years, after which less children shifted to other BMI classes. A total of 55-78% of children with overweight at 3-4 years retained their overweight at 13-15 years, and 10-20% of 3-4 year olds with thinness remained thin. CONCLUSIONS: In all ethnic groups, overweight and especially thinness highly tracked into adolescence. South Asian children differed from the other ethnic groups when universal BMI criteria were applied, but with South Asian specific BMI criteria tracking patterns became more concordant.

BMI-for-age in South Asian children of 0-20 years in the Netherlands: secular changes and misclassification by WHO growth references.

BACKGROUND: South Asians are prone to cardiometabolic disease at lower BMI levels than most other ethnic groups, starting in childhood. The magnitude of BMI misclassifications is unknown. AIM: To compare the BMI distribution of contemporary South Asian 0-20 year olds in the Netherlands with: (1) The South Asian norm reference (secular trends); and (2) The WHO child growth standard and reference. SUBJECTS AND METHODS: The BMI-for-age distribution of 6677 routine measurements of 3322 South Asian children, aged 0-20 years, was described with the LMS method and BMI z-scores. RESULTS: The BMI distribution in South Asian 0-4 year olds was almost similar to the norm reference (mean BMI z-score = 0.11, skewness = 0.31, SD = 1.0), whereas in 5-19 year olds the distribution had shifted upwards (mean = 0.53) and widened (skewness = -0.12, SD = 1.08). Overweight (incl. obesity) and obesity peaked at 8-10 years, at 45-48% and 35-37%, respectively. Relative to the WHO references, the BMI distribution was left-shifted at ages 0-4 years (mean BMI z-score = -0.46, skewness = 0.23, SD = 0.98) and widened at ages 5-20 years (mean = 0.05; skewness = -0.02, SD = 1.40). At most ages, thinness rates were significantly higher and obesity rates lower than based on South Asian norms. CONCLUSIONS: A secular change of BMI-for-age in South Asian children mostly affected children >4 years. WHO references likely under-estimate overweight and obesity rates in South Asian children.

Outcome of liver transplantation in patients with hereditary bleeding disorders: a single centre UK experience.

INTRODUCTION: Patients with hereditary bleeding disorders who have developed end-stage liver disease as a consequence of hepatitis C infection (HCV) acquired from factor concentrates prior to the introduction of viral inactivation continue to be referred for liver transplantation. METHODS: A retrospective review of case notes and electronic records was performed on all patients with bleeding disorders who have undergone liver transplantation at the University Hospital Birmingham (UHB). RESULTS: Between 1990 and 2014, 35 liver transplants have been performed in 33 patients with hereditary bleeding disorders. The indication for transplantation was mainly end-stage liver disease secondary to HCV. Five patients had human immunodeficiency virus (HIV) co-infection. No excess mortality due to bleeding occurred in the peri or postoperative period. Median overall survival post transplant is 9.7 years. Overall survival rates at 1, 3 and 5 years are 90%, 72% and 64% respectively. The predominant cause of mortality was liver failure secondary to either recurrent HCV or recurrent hepatocellular carcinoma (HCC). The median overall survival in patients with HIV co-infection is shorter than in those with mono-infection but this is not statistically significant. Patients with a pre-existing HCC had a statistically significant shorter survival (2.4 years vs. 13.6 years, P = 0.007). CONCLUSION: Liver transplantation has become an accepted treatment option for patients with hereditary bleeding disorders and HCV associated end-stage liver disease with survival rates similar to non-bleeding disorder patients.

Role of focused assessment with sonography for trauma as a screening tool for blunt abdominal trauma in young children after high energy trauma.

BACKGROUND: The objective of the study was to review the utility of focused assessement with sonography for trauma (FAST) as a screening tool for blunt abdominal trauma (BAT) in children involved in high energy trauma (HET), and to determine whether a FAST could replace computed tomography (CT) in clinical decision-making regarding paediatric BAT. METHOD: Children presented at the Trauma Unit of the Red Cross War Memorial Children's Hospital, Cape Town, after HET, and underwent both a physical examination and a FAST. The presence of free fluid in the abdomen and pelvis was assessed using a FAST. Sensitivity, specificity, and positive and negative predictive values (PPV and NPV) for identifying intraabdominal injury were calculated for the physical examination and the FAST, both individually and when combined. RESULTS: Seventy-five patients were included as per the criteria for HET as follows: pedestrian motor vehicle crashes (MVCs) (n = 46), assault (n = 14), fall from a height (n = 9), MVC passenger (n = 4) and other (n = 2). The ages of the patients ranged from 3 months to 13 years. The sensitivity of the physical examination was 0.80, specificity 0.83, PPV 0.42 and NPV 0.96. The sensitivity of the FAST was 0.50, specificity 1.00, PPV 1.00 and NPV 0.93. Sensitivity increased to 0.90 when the physical examination was combined with the FAST. Nonoperative management was used in 73 patients. Two underwent an operation. CONCLUSION: A FAST should be performed in combination with a physical examination on every paediatric patient involved in HET to detect BAT. When both are negative, nonoperative management can be implemented without fear of missing a clinically significant injury. FAST is a safe, effective and easily accessible alternative to CT, which avoids ionising radiation and aids in clinical decision-making.

Local vibrations and negative thermal expansion in ZrW2O8.

We present an x-ray pair distribution function (XPDF) analysis and extended x-ray absorption fine structure (EXAFS) data for ZrW2O8 (10-500 K) with a focus on the stiffness of the Zr-O-W linkage. The XPDF is highly sensitive to W-Zr and W-W correlations, but much less so to O-O or W-O correlations. The Zr-W peak in the XPDF data has a weak temperature dependence and, hence, this linkage is relatively stiff and does not permit bending of the Zr-O-W link. We propose that the low energy vibrational modes that lead to negative thermal expansion involve correlated rotations of ZrO6 octahedra that produce large <111> translations of the WO4 tetrahedra, rather than a transverse motion of O atoms that imply a flexible Zr-O-W linkage.

Antiferromagnetic order and its interplay with superconductivity in CaK(Fe1-xMnx)4As4.

The magnetic order for several compositions of CaK(Fe1-xMnx)4As4has been studied by nuclear magnetic resonance (NMR), Mössbauer spectroscopy, and neutron diffraction. Our observations for the Mn-doped 1144 compound are consistent with the hedgehog spin vortex crystal (hSVC) order which has previously been found for Ni-dopedCaKFe4As4. The hSVC state is characterized by the stripe-type propagation vectors(π0)and(0π)just as in the doped 122 compounds. The hSVC state preserves tetragonal symmetry at the Fe site, and only this SVC motif with simple antiferromagnetic (AFM) stacking alongcis consistent with all our observations using NMR Mössbauer spectroscopy, and neutron diffraction. We find that the hSVC state in the Mn-doped 1144 compound coexists with superconductivity, and by combining the neutron scattering and Mössbauer spectroscopy data we can infer a quantum phase transition, hidden under the superconducting dome, associated with the suppression of the AFM transition temperature (TN) to zero forx ≈ 0.01. In addition, unlike several 122 compounds and Ni-doped 1144, the ordered magnetic moment is not observed to decrease at temperatures below the superconducting transition temperature (Tc).

The UK Haemophilia Doctors Organisation triennial audit of UK Comprehensive Care Haemophilia Centres.

Under the auspices of the United Kingdom Haemophilia Doctors Organisation (UKHCDO) the UK Comprehensive Care Haemophilia Centres (CCCs) have undergone a three yearly formal audit assessment since 1993. This report describes the evolution of the audit process and details the findings of the most recent audit round, the sixth since inception. The audit reports from the 2009 audit round were reviewed by the audit organizing group and a structured analysis of the data was compiled. CCCs in the UK offer a high standard of comprehensive care services. The main areas of concern were the state of the premises (seven centres), lack of dental services (seven centres), physiotherapy (seven centres) and social work support (11 centres). Major concerns were identified at eight centres requiring a formal letter from the chairman of UKHCDO to the chief executive of the host trust. Since inception of the triennial audit process centre report recommendations have resulted in major improvements in the services available at UK CCCs. The audit process is considered to be a highly effective means of improving the quality of care for patients with bleeding disorders and can be used as a model for the introduction of a similar process in other countries.

Randomized, prospective, observational simulation study comparing residents' needle-guided vs free-hand ultrasound techniques for central venous catheter access.

BACKGROUND: Short-axis ultrasound-guided placement of central venous catheters (CVCs) is widely accepted as safe practice. However, utilizing the long-axis approach could further improve safety, as it allows for better visualization of the needle as it is advanced to the target vessel. However, the long-axis approach has not widely been used due to the technical difficulty. Recently, a new needle guidance device has become available to aid in the long-axis approach. We hypothesized that the use of a needle guide paired with the long-axis approach would facilitate puncture of the target vessel in a simulation model more effectively than similar free-hand techniques. METHODS: A prospective observational study of anaesthesia residents using a CVC partial-task training device was conducted. Each resident performed needle puncture of the target vessel with three different techniques, assigned in random order: short-axis free hand (S-FH), long-axis free hand (L-FH), and long-axis needle guide (NG). To prove the effectiveness of the needle guide, the fraction of time the needle tip remained in view of the ultrasound was recorded and compared. Time required for completing the task and the number of needle sticks and needle re-directions were compared. RESULTS: Thirty-three residents participated in the study. The fraction of time the needle tip remained in view of the ultrasound was significantly higher for the residents using NG [0.90 (0.10)] compared with residents using the other techniques [L-FH: 0.36 (0.20), S-FH: 0.18 (0.10)] (P<0.001). For each resident, the use of the needle guide in the long-axis approach increased visualization by 352 (276)% compared with that of L-FH and by 1028 (1804) % compared with that of S-FH. There was no significant difference in time required to puncture the target between NG [23.7 (14.6) s] and L-FH [30.3 (36.5) s] (P=0.21); however, both were significantly longer than S-FH [17.0 (13.3) s] (P=0.012). The numbers of needle sticks and of needle re-directions did not differ among the groups. CONCLUSIONS: The needle guide device used in the long-axis approach improved the needle visualization compared with free-hand techniques. The needle guide used in the long-axis technique, however, did not facilitate puncture of the target vessel in this simulation model when compared with free-hand techniques.

Experience of four UK comprehensive care centres using FEIBA® for surgeries in patients with inhibitors.

Increasing evidence indicates that factor VIII (FVIII) inhibitor bypassing agents (FEIBA® and NovoSeven®) can provide effective peri-operative haemostasis in haemophilia patients with high-responding inhibitors. We report the collected experience of all major and minor surgeries, conducted between December 1998 and September 2008, at four UK haemophilia Comprehensive Care Centres with FEIBA® as the first-line bypassing agent in patients with inhibitors. A total of 26 surgical procedures were performed in 18 patients of ages 34-83 years including five patients with acquired FVIII inhibitors. A single pre-operative infusion of FEIBA was followed by 6-12 h interval dosing for major surgeries at the discretion of the physician to approximate a maximum of 200 U kg(-1) day(-1), with tapering when postoperative haemostasis and wound healing permitted. Haemostatic outcomes were retrospectively reviewed against European consensus thresholds for blood loss and duration of treatment compared with expectations for equivalent procedures in non-inhibitor patients. Peri-operative haemostatic outcome with FEIBA was rated excellent or good in 78% of 18 major surgeries in 12 patients, including 11 major orthopaedic procedures. Haemostatic outcome was rated excellent in all seven procedures in five patients with acquired FVIII inhibitors and in all eight minor surgical procedures in six patients. FEIBA was well tolerated with no intra-operative haemostatic complications. A single, transient postoperative thrombotic adverse event occurred in a patient with cerebrovascular disease. This case series adds significantly to existing evidence that FEIBA can provide adequate, well-tolerated, peri-operative haemostatic cover for a wide variety of major and minor surgical procedures.

UKHCDO guidelines on the management of HCV in patients with hereditary bleeding disorders 2011.

Chronic HCV infection continues to be of significant clinical importance in patients with hereditary bleeding disorders. This guideline provides information on the recent advances in the investigation and treatment of HCV infection and gives GRADE system based recommendations on the management of the infection in this patient group.

The risk of variant Creutzfeldt-Jakob disease among UK patients with bleeding disorders, known to have received potentially contaminated plasma products.

The risk of variant Creutzfeldt-Jakob disease (vCJD) from potentially infected plasma products remains unquantified. This risk has been assessed for 787 UK patients with an inherited bleeding disorder prospectively followed-up for 10-20 years through the UK Haemophilia Centre Doctors' Organisation (UKHCDO) Surveillance Study. These patients had been treated with any of 25 'implicated' clotting factor batches from 1987 to 1999, which included in their manufacture, plasma from eight donors who subsequently developed clinical vCJD. Variant CJD infectivity of these batches was estimated using plasma fraction infectivity estimates and batch-manufacturing data. Total potential vCJD infectivity received by each patient has been estimated by cumulating estimated infectivity from all doses received during their lifetime. Of 787 patients, 604 (77%) were followed-up for over 13 years following exposure to an implicated batch. For these 604 patients, the estimated vCJD risk is ≥ 1% for 595, ≥ 50% for 164 and 100% for 51. This is additional to background UK population risk due to dietary exposure. Of 604 patients, 94 (16%) received implicated batches linked to donors who developed clinical vCJD within 6 months of their donations. One hundred and fifty-one (25%) had received their first dose when under 10 years of age. By 1st January 2009, none of these patients had developed clinical vCJD. The absence of clinical vCJD cases in this cohort to date suggests that either plasma fraction infectivity estimates are overly precautionary, or the incubation period is longer for this cohort than for implicated cellular blood product recipients. Further follow-up of this cohort is needed.

FEIBA prophylaxis in haemophilia patients: a clinical update and treatment recommendations.

In patients with severe haemophilia and inhibitors, regular factor VIII inhibitor bypassing activity (FEIBA) prophylaxis has been shown to reduce the frequency of bleeding by up to 85% and to improve patient quality of life. FEIBA is well tolerated; the incidence of thrombotic events and of allergic reactions is extremely low. The concept of prophylaxis in haemophilia patients with inhibitors is relatively new and some clinicians may be unsure of how to use FEIBA in this context. These treatment recommendations, based on published evidence plus the collective experience of a group of haematologists (with practical knowledge of managing inhibitor patients with FEIBA prophylaxis), are intended to provide guidance to clinicians considering initiating and maintaining patients on FEIBA prophylaxis with specific focus on practical aspects of patient selection, dosing, monitoring and stop criteria.

Risk reduction strategies for variant Creutzfeldt-Jakob disease transmission by UK plasma products and their impact on patients with inherited bleeding disorders.

SUMMARY: The appearance and rapid evolution of BSE in UK cattle in the mid 1980s, with compelling data supporting variant Creutzfeldt-Jakob disease (vCJD) as its human manifestation, pose a potentially severe threat to public health. Three clinical cases and one asymptomatic case of vCJD infection have been reported in UK recipients of non-leucodepleted red cell transfusions from donors subsequently diagnosed with vCJD. Plasma from both these and other donors who later developed vCJD has contributed towards plasma pools used to manufacture clotting factor concentrate. The United Kingdom Haemophilia Centre Doctors' Organisation (UKHCDO) Surveillance Study has detected asymptomatic vCJD postmortem in a haemophilic patient treated with UK plasma products including two batches of clotting factor linked to a donor who subsequently developed vCJD. Over 4000 bleeding disorder patients treated with UK plasma products are recorded on the UKHCDO National Haemophilia Database. The risk of vCJD transmission by plasma products is not known. However, public health precautions have been implemented since 2004 in all UK inherited bleeding disorder patients who received UK-sourced plasma products between 1980 and 2001 to minimize the possible risk of onward vCJD transmission. We evaluate vCJD surveillance and risk management measures taken for UK inherited bleeding disorder patients, report current data and discuss resultant challenges and future directions.

Long-term outcome of successful percutaneous transluminal angioplasty of the fibular artery in diabetic foot syndrome and single-vessel calf perfusion depends on doppler wave pattern at the forefoot.

BACKGROUND: In the diabetic foot syndrome (DFS) due to peripheral artery disease, the fibular artery is often the only vessel which can be revascularised. Because the fibular artery does not have a direct connection to the plantar arch, the clinical result of fibular artery PTA is dependent upon the extent of collateralization at the ankle. Therefore, successful PTA of the fibular artery with resulting biphasic doppler waves at the ankle can lead to either biphasic or monophasic post-occlusive doppler wave patterns at the forefoot. We evaluated prospectively the association of the forefoot doppler wave form on long-term clinical outcome in patients with DFS after successful PTA of the fibular artery. PATIENTS AND METHODS: 44 patients with occluded calf vessels and DFS Wagner 2-4 underwent primary successful fibular artery PTA resulting in biphasic ankle doppler wave. According to doppler wave form at the forefoot, patients were divided into 1) a biphasic or 2) a monophasic group. Up to 45 months, we documented doppler wave forms, clinical course, restenosis, reinterventions, wound healing, major- and minor amputations. RESULTS: PTA resulted in a biphasic doppler wave at the forefoot in 26 (59 %), in 18 (41 %) in a monophasic wave pattern. Biphasic forefoot doppler wave was strongly correlated with longer event-free survival (35 bi- vs. 5.5 months monophasic, p = 0.0018) and complete wound healing (69 % s bi- vs. 44 % vs. monophasic p = 0.0309). Major amputations: 2 / 26 (8 %) in the biphasic and in 3 / 18 (17 %) in the monophasic group. Second revascularisation procedures were more often necessary in the monophasic group (7 / 18 (39 % vs. 2 / 26 (8 %)). CONCLUSION: After successful PTA of the fibular artery, monophasic doppler wave patterns at the forefoot denote insufficient collateralization and are associated with poor outcome. If successful fibular artery PTA results only in monophasic forefoot doppler, additional crural or pedal bypass should be strongly contemplated.

Phenotypic approaches to gene mapping in platelet function disorders - identification of new variant of P2Y12, TxA2 and GPVI receptors.

Platelet number or function disorders cause a range of bleeding symptoms from mild to severe. Patients with platelet dysfunction but normal platelet number are the most prevalent and typically have mild bleeding symptoms. The study of this group of patients is particularly difficult because of the lack of a gold-standard test of platelet function and the variable penetrance of the bleeding phenotype among affected individuals. The purpose of this short review is to discuss the way in which this group of patients can be investigated through platelet phenotyping in combination with targeted gene sequencing. This approach has been used recently to identify patients with mutations in key platelet activation receptors, namely those for ADP, collagen and thromboxane A2 (TxA2). One interesting finding from this work is that for some patients, mild bleeding is associated with heterozygous mutations in platelet proteins that are co-inherited with other genetic disorders of haemostasis such as type 1 von Willebrand's disease. Thus, the phenotype of mild bleeding may be multifactorial in some patients and may be considered to be a complex trait.

Consensus protocol for the use of recombinant activated factor VII [eptacog alfa (activated); NovoSeven] in elective orthopaedic surgery in haemophilic patients with inhibitors.

Patients with haemophilia complicated by inhibitors have a significant burden of joint disease, which is associated with a negative impact on their quality of life. Successful elective orthopaedic surgery can result in decreased bleed frequency into a new joint, less time spent in hospital, increased mobility and improved well being. This paper describes a new protocol for use of recombinant activated factor VII (rFVIIa) in elective orthopaedic surgery, based on a review of published data as well as the personal experience of a group of expert physicians. The protocol offers guidance on the planning of the surgery and preoperative testing as well as the bolus schedule for rFVIIa and advice on the concomitant use of antifibrinolytic agents and fibrin sealants. A total of 10 operations involving 13 procedures in eight patients in five comprehensive care centres have been undertaken until now using the protocol, which employs an initial bolus dose of rFVIIa in the range of 120-180 microg kg(-1) to cover surgery. The clinical experience reported here encompasses all cases of elective orthopaedic surgery using rFVIIa as initial treatment carried out in the UK and Republic of Ireland over the last 2 years. In all cases, there was good control of haemostasis during surgery and the final outcome was rated as 'excellent' or 'extremely satisfactory' by the reporting clinicians. Although the initial cost of product to cover surgery such as arthroplasty is high, it needs to be borne in mind that this may be offset in subsequent years by savings resulting from avoidance of bleeding episodes in the affected joint.