Cervical dilation at time of caesarean delivery in nulliparous women: a population-based cohort study.

OBJECTIVES: Our objective was to describe contemporary practice patterns in the timing of caesarean delivery in relation to cervical dilation, overall and by indication for caesarean. Our secondary objective was to examine how commonly caesarean delivery was performed for labour dystocia at dilations below 4 cm or without the use of oxytocin, overall and between hospitals. DESIGN: Retrospective, population-based cohort study. SETTING: Ontario, Alberta, and British Columbia, Canada, 2008-2012. POPULATION: Nulliparous women in labour who delivered term singletons in cephalic position. METHODS: Histograms were used to examine the distribution of cervical dilation at time of caesarean delivery, overall and by indication for caesarean. Funnel plots were used to illustrate variation in hospital-level rates of caesarean deliveries for labour dystocia that were performed early (<4 cm dilation) or without the use of oxytocin. MAIN OUTCOME MEASURES: Cervical dilation (in centimetres) at time of caesarean delivery. RESULTS: The population-based cohort comprised 392 025 women, of whom 18.8% had a caesarean delivery. Of first-stage caesareans for labour dystocia in women who entered labour spontaneously, 13.6% (95% CI 12.9, 14.2) had dilations <4 cm [hospital-level inter-quartile range (IQR): 6.2% to 20.0%] and 29.5% (95% CI 28.6, 30.4) did not receive oxytocin to treat their dystocia (hospital-level IQR: 22.1-54.6%). CONCLUSIONS: The proportion of caesareans done before 4 cm dilation or without oxytocin varies substantially across hospitals and suggests the need for institutions to review their practices and ensure that management of labour practice guidelines are followed. TWEETABLE ABSTRACT: Many caesareans for labour dystocia are performed early during labour (<4 cm dilation) or without oxytocin.

Accessing fertility treatment in New Zealand: a comparison of the clinical priority access criteria with a prediction model for couples with unexplained subfertility.

BACKGROUND: In New Zealand, public funding for assisted reproductive technology (ART) is restricted to subfertile women who are unlikely to conceive spontaneously, based on clinical and social criteria known as the clinical priority access criteria (CPAC) score. The objective of this study was to compare this CPAC score with a prediction model for predicting spontaneous conception, developed in the Netherlands (the Hunault model). METHODS: We performed a cohort study and included couples with unexplained subfertility and assessed the measure of agreement and the performance of the CPAC score and the Hunault prediction score. RESULTS: Of 663 couples referred, 249 (38%) couples had unexplained subfertility. Of 246 women with full follow-up data, there were 143 women (58%) who had a live birth during the follow-up period, 65 (26%) after fertility treatment and 78 (32%) after natural conception. There were 100 couples (41%) who had a Hunault prediction score of <30%, which is the Dutch treatment threshold, and 36 couples (15%) who had a CPAC score of >65, which is the New Zealand threshold for publically funded treatment. There were 69 couples (28%) who meet the threshold for treatment in the Netherlands but did not meet the New Zealand threshold for public funding. The kappa coefficient as a measure of agreement of the two scores and their treatment thresholds was 0.30, suggesting a fair agreement. The area under the curve for the CPAC and Hunault scores were both 0.63, but the Hunault model performed better in calibration. CONCLUSIONS: The CPAC score correlates fairly with the Hunault prediction score, although using the Hunault prediction model 26% more couples would be recommended for ART. The discriminative capacities of both scores were comparable, but the Hunault prediction score performed better in calibration. Funding models in New Zealand should consider treating those women with unexplained subfertility who are least likely to conceive spontaneously.

Pathways to immunity: temporal dynamics of the bumblebee (Bombus terrestris) immune response against a trypanosomal gut parasite.

Immune response dynamics in insects from natural host-parasite associations are poorly understood, despite accumulating evidence of ecological immune phenomena in these systems. Using a gene discovery approach, we have identified genes relating to signalling, enzymatic processes and respiration that were up-regulated in the bumblebee, Bombus terrestris, during infection with the trypanosomatid parasite, Crithidia bombi. In addition, we have mapped dynamic changes in the temporal expression of these genes and three candidate antimicrobial peptide (AMP) immune genes, Abaecin, Defensin and Hymenoptaecin, from 1 to 24 h after C. bombi infection. We show that dynamic changes in expression occur for individual genes at distinct phases of the immune response to C. bombi that correspond to early, intermediate and late stages of infection.

Hypofractionated Stereotactic Ablative Radiotherapy for Recurrent or Oligometastatic Tumours in Children and Young Adults.

AIMS: Cancer remains a leading cause of death in children and adolescents in the developed world. Despite advances in oncological management, rates of primary treatment failure remain significant. Radiation of recurrent or metastatic disease improves survival in adults but there is little data to support clinical decision making in the paediatric/teenage and young adult population. MATERIALS AND METHODS: We present a retrospective case series of 14 patients treated with stereotactic ablative body radiotherapy or stereotactic radiosurgery at The Royal Marsden Hospital from September 2011 to December 2015. Eligible patients were aged <25 years, with Lansky/Karnofsky performance status ≥60 with confirmed relapsed or metastatic tumour in fewer than three sites. Follow-up was in accordance with standard clinical care and included regular outpatient review and radiological surveillance. Local control, progression-free survival and overall survival are presented. RESULTS: Data for 14 patients with 18 treated lesions were included. The median patient age was 15 years (range 5-20 years). Nine patients were treated for local recurrence and five for metastatic lesions. All patients had already undergone multiple previous treatments. Eleven patients had undergone previous radiotherapy. The median interval between the completion of initial radiotherapy and reirradiation was 29.0 months (range 0.2-49.5 months). The median follow-up was 3.4 years (range 0.28-6.4 years). The 1-year local control rate was 78.6% and the 2-year local control rate was 57.1%. Overall median survival was 58.4 months (95% confidence interval 33.8-82.9 months). Cumulative biologically effective doses (BED) over 200 Gy were associated with late toxicity (P = 0.04). CONCLUSION: Radical doses of short-course hypofractionated radiotherapy can achieve excellent local control and may contribute to the prolongation of overall survival. There is a need for prospective trials exploring the use of ablative radiotherapy in metastatic disease in paediatric/teenage and young adult patients in order to establish safe and effective treatment schedules.

Noise reduction in oncology FDG PET images by iterative reconstruction: a quantitative assessment.

UNLABELLED: Tumor detection depends on the contrast between tumor activity and background activity and on the image noise in these 2 regions. The lower the image noise, the easier the tumor detection. Tumor activity contrast is determined by physiology. Noise, however, is affected by many factors, including the choice of reconstruction algorithm. Previous simulation and phantom measurements indicated that the ordered-subset expectation maximization (OSEM) algorithm may produce less noisy images than does the usual filtered backprojection (FBP) method, at equivalent resolution. To see if this prediction would hold in actual clinical situations, we quantified noise in clinical images reconstructed with both OSEM and FBP. METHODS: Three patients (2 with colon cancer, 1 with breast cancer) were imaged with FDG PET using a "gated replicate" technique that permitted accurate measurement of noise at each pixel. Each static image was acquired as a gated image sequence, using a pulse generator with a 1-s period, yielding 40 replicate images over the 10- to 15-min imaging time. The images were or were not precorrected for attenuation and were reconstructed with both FBP and OSEM at comparable resolution. From these data, images of pixel mean, SD, and signal-to-noise ratio (S/N) could be produced, reflecting only noise caused by the statistical fluctuations in the emission process. RESULTS: Noise did not vary greatly over each FBP image, even when image intensity varied greatly from one region to the next, causing S/N to be worse in low-activity regions than in high-activity regions. In contrast, OSEM had high noise in hot regions and low noise in cold regions. OSEM had a much better S/N than did FBP in cold regions of the image, such as the lungs (in the attenuation-corrected images), where improvements in S/N averaged 160%. Improvements with OSEM were less dramatic in hotter areas such as the liver (averaging 25% improvement in the attenuation-corrected images). In very hot tumors, FBP actually produced higher S/Ns than did OSEM. CONCLUSION: We conclude that OSEM reconstruction can significantly reduce image noise, especially in relatively low-count regions. OSEM reconstruction failed to improve S/N in very hot tumors, in which S/N may already be adequate for tumor detection.

Evaluation of pre- and post-reconstruction count-dependent Metz filters for brain PET studies.

In this study we evaluated pre- (PR-R) and post-reconstruction (PO-R) count-dependent Metz filters for PET brain studies in order to increase signal-to-noise ratio. A set of studies using a 3D Hoffman brain phantom was performed at various count levels, and a reference image set was created from extremely high count images. Several combinations of PR-R and PO-R filtering were considered to find the optimal means of processing, including: Hann filter alone; PR-R Metz filter without or with a PO-R low pass filter; and PO-R Metz filter without or with a PR-R low pass filter. A formula was established to correlate the optimal PO-R Metz filter order with the net counts. Resolution [full width at half-maximum (FWHM) and fill width at tenth maximum (FWTM)], normalized residual mean square differences (NRMSD) between the ideal and the processed images, noise reduction and contrast were used as parameters for the evaluation of the different filter combinations. Resolution is decreased by all filter combinations that can effectively control noise; however, FWTM increases less than FWHM. NRMSD indicates that the use of Hann and (optimal) PO-R Metz filter is the most powerful combination from among those tested. A close correlation (r = 0.969) was found between the net counts and the optimal order of the PO-R Metz filter. At the count levels of clinical studies the PO-R Metz filter was found to control noise much more effectively and enhance the contrast when compared to the routinely used Hann filter alone, and produced images of better quality.

Noninvasive estimation of the aorta input function for measurement of tumor blood flow with.

Quantitative measurement of tumor blood flow with [15O]water can be used to evaluate the effects of tumor treatment over time. Since quantitative flow measurements require an input function, we developed the profile fitting method (PFM) to measure the input function from positron emission tomography images of the aorta. First, a [11C]CO scan was acquired and the aorta region was analyzed. The aorta diameter was determined by fitting the image data with a model that includes scanner resolution, the measured venous blood radioactivity concentration, and the spillover of counts from the background. The diameter was used in subsequent fitting of [15O]water dynamic images to estimate the aorta and background radioactivity concentrations. Phantom experiments were performed to test the model. Image quantification biases (up to 15%) were found for small objects, particularly for those in a large elliptical phantom. However, the bias in the PFM concentration estimates was much smaller (2%-6%). A simulation study showed that PFM had less bias and/or variability in flow parameter estimates than an ROI method. PFM was applied to human [11C]CO and [15O]water dynamic studies with left ventricle input functions used as the gold standard. PFM parameter estimates had higher variability than found in the simulation but with minimal bias. These studies suggest that PFM is a promising technique for the noninvasive measurement of the aorta [15O]water input function.

The approximate inverse and conjugate gradient: non-symmetrical algorithms for fast attenuation correction in SPECT.

Hybrid methods have been known for a long time as very efficient algorithms for attenuation correction in single-photon emission computed tomography, but only recently have efforts been made to formulate them with more rigorous mathematics. This has allowed us to explain their efficiency in terms of approximate inversion, and to establish a convergence condition. The present study focuses on the convergence problem and emphasizes the question of symmetry. Hybrid method operators are not symmetrical; therefore the convergence condition is not easily verified. New schemes based on a modified conjugate gradient method are presented. Convergence is proved and performances are shown to be at least as good as the standard hybrid schemes on perfect and noisy simulated data.

A retrospective study of circovirus infection in pigeons: nine cases (1986-1993).

Circovirus infections were diagnosed in 12 pigeons from the United States 4 pigeons from Australia, and 1 pigeon from Canada (1986-1993). Circovirus was identified by electron microscopic examination of basophilic botryoid cytoplasmic inclusions that had a histologic appearance similar to that of psittacine beak and feather disease virus inclusions. Inclusions were seen in splenic, bursal, gut-associated, and bronchus-associated lymphoid tissue macrophages and in bursal epithelial cells. Inclusions were composed of paracrystalline arrays of tightly packed, nonenveloped icosahedral virions 14-17 nm in diameter. Histologic changes in the spleens ranged from lymphofollicular hyperplasia with mild discrete lymphocellular necrosis to lymphoid depletion and diffuse histiocytosis. Lesions in the bursa of Fabricius ranged from mild lymphocellular necrosis to severe cystic bursal atrophy. Remaining histologic findings coincided with concurrent bacterial, viral, fungal, and parasitic infections. Immunoperoxidase staining and DNA in situ hybridization demonstrated that pigeon circovirus is distinct from psittacine beak and feather disease virus; however both viruses apparently share some homologous DNA sequences. Clinical and diagnostic findings indicate that pigeon circovirus may be similar to psittacine beak and feather disease virus with respect to acquired immunodeficiency and subsequent multiple secondary infections.

Pathology of the skeleton and tendons of broiler chickens reared to roaster weights. I. Crippled chickens.

The incidence of cripples among broiler chickens kept until 74 days of age was greatest in chickens fed ad libitum and kept in batteries. The incidence was lower in chickens kept in floor pens and was reduced by feed restriction. Crippling was due to long-bone distortion, rupture of the gastrocnemius tendon, and spondylolisthesis. Long-bone distortion was the most common defect and could be divided into valgus and varus deformation. The former was more important in chickens less than 7 weeks of age, and the latter was more important in older chickens. Tibial dyschondroplasia was found in some chickens with long-bone distortion, and the possible significance of this abnormal cartilage as a cause of long-bone distortion is discussed.

Rickets in turkey poults.

Fifteen outbreaks of rickets were diagnosed in turkey poults in Saskatchewan between 1978 and 1981. No relationship to farm, source of poults, or source of feed was apparent. Most outbreaks started when the poults were between 10 and 14 days of age, and they had recovered by 28 days of age. Losses varied from 1% to 14% of poults started. Skeletal lesions were characteristic of a vitamin D or calcium deficiency. On the basis of chemical analyses, adequate levels of calcium and phosphorus and proper amounts of vitamin premixes were present in the feed, but in five outbreaks biological feed tests implicated feed as a causative factor. The severity of rickets in poults fed defective feeds was markedly reduced by providing the poults with extra vitamin D in the drinking water or by injection. Two premixes used in different feeds contained adequate available vitamin D on the basis of biological testing. In some of the outbreaks, the rickets may have resulted from inadequate distribution of vitamin D in the feed, destruction of vitamin D during feed processing, or some unknown factor in the feed interfering with vitamin D utilization.

Viral hepatitis in domestic geese in Saskatchewan.

Up to 25% mortality occurred in goslings between 8 and 28 days of age in three sequential hatches from a closed breeder flock on a single farm. The birds died suddenly with minor ascites, subcutaneous and myocardial hemorrhages, and pale, mottled livers with petechial hemorrhages. Liver necrosis associated with intranuclear inclusion bodies was seen on histology. Virus particles were found on examination of the inclusion bodies with an electron microscope. Liver homogenates caused variable mortality 7 to 17 days postinoculation in goose embryos, some of which had hepatic necrosis and intranuclear inclusion bodies. Experimental goslings inoculated with material from these infected embryos died from hepatitis.

Studies on the pathogeneis of tibial dyschondroplasia in chickens. IV. Some features of the vascular supply to the growth plates of the tibiotarsus.

Several features of the vascular supply to the growth plates of the tibiotarsus were compared in two strains of broiler chickens selected for a high and low incidence of tibial dyschondroplasia. No difference was found between the two strains in the area of the proximal growth plate of the tibiotarsus or in the distance of the nutrient foramen from the same growth plate. Vascular tunnels invading the zone of hypertrophy were significantly fewer in the proximal growth plate than in the distal growth plate, and tunnels invading the zone of hypertrophy of each growth plate were also fewer in the high-incidence chickens than in the low-incidence chickens.

The development of tibial dyschondroplasia in broiler chickens.

Two strains of broiler chickens selected for a high and a low incidence of tibial dyschondroplasia were fed a standard broiler starter ration with and without added chloride. Development of tibial dyschondroplasia was studied by radiography and serial necropsies. Lesions of tibial dyschondroplasia were mild in the low-incidence strain, regardless of ratio. The defect was more severe in the high-incidence strain and most severe in those birds fed the high-chloride ration. An abnormal thickening of the growth plate was apparent in the high-incidence strain as early as 2 weeks of age and became progressively more severe with age. No significant differences were noted in serum calcium, phosphorus, alkaline phosphatase, pCO2, or bone ash between strains of birds or between birds of the same strain fed different rations. Birds fed the high-chloride ration had a higher serum chloride and a lower serum bicarbonate and blood pH than birds on the standard ration.

Studies on the pathogenesis of tibial dyschondroplasia in chickens. I. Production of a similar defect by surgical interference.

The prehypertrophic cartilage in the proximal growth plate of the tibiotarsus in chickens persisted after surgical destruction of the metaphyseal blood supply. The persistent cartilage was grossly and histologically similar to abnormal cartilage from natural cases of tibial dyschondroplasia.

Studies on the pathogenesis of tibial dyschondroplasia in chickens. III. Effect of body weight.

Surgical severance of the gastrocnemius and flexor tendons on the posterior aspect of the tibiotarsal-tarsometatarsal joint in one leg resulted in unilateral lameness in chickens that were susceptible to tibial dyschondroplasia. Perotic-like deformation developed in the operated leg, while the tibiotarsus in the unoperated leg was thicker and bowed in an anterior direction. In nine of 43 chickens with tibial dyschondroplasia the severity of the lesion differed markedly between the operated and unoperated legs. The more severe lesion was in the operated leg in 6 birds, and in the unoperated leg in 3 birds. No evidence was found to support the hypothesis that weight-bearing may be important in the pathogenesis of tibial dyschondroplasia.

Studies on the pathogenesis of tibial dyschondroplasia in chickens. II. Growth rate of long bones.

The growth rate of the tibiotarsus, tarsometatarsus, and humerus was studied in two strains of chickens selected for a high and low incidence of tibial dyschondroplasia. The proximal growth plates grew more rapidly than the distal growth plates. The proximal growth plate of the tibiotarsus grew fastest, while those of the tarsometatarsus and humerus had growth rates that were respectively 4 and 33% slower. The bones averaged slightly faster growth in the high-incidence strain than in the low-incidence strain. A slowed growth decreased the incidence of tibial dyschondroplasia. However, lack of correlation between growth rate and the development of tibial dyschondroplasia in individual chickens suggested that growth rate may be no more than a contributing factor.

Toxicity of dimetridazole in waterfowl.

Dimetridazole at a concentration of 1.0 g/l in drinking water caused mortality in both ducklings and goslings. When given to goslings at a concentration of 0.5 g/l, the drug caused growth depression and nervous signs characterized by excess activity, abnormal head attitudes, and ataxia.