Real Time Volumetric MRI for MR-Guided 3D Motion Tracking via Sparse Prior-Augmented Neural Representation Learning

PURPOSE/OBJECTIVE(S)

To reconstruct volumetric MRI from orthogonal cine acquisition aided by sparse priors of 2 static 3D MRI through implicit neural representation (NeRP) learning, with the goal of eliminating large-scale training datasets for data-driven sparse MRI reconstruction and supporting clinical workflow of real time 3D motion tracking during MR-guided radiotherapy.

MATERIALS/METHODS

A multi-layer perceptron network was trained to learn the NeRP of a patient-specific MRI dataset, where the network takes 4D data coordinates of voxel locations and motion states as inputs and outputs corresponding voxel intensities. By first learning the NeRP of 2 static 3D MRI with different breathing motion states, prior knowledge of patient breathing motion was embedded into network weights through optimization. The prior knowledge was then augmented from 2 to 31 motion states by querying the optimized network at interpolated/extrapolated motion state coordinates. Starting from the prior-augmented network as an initialization point, the network was further trained using sparse samples of 2 orthogonal cine slices. The final volumetric reconstruction was obtained by querying the trained network at desired 3D spatial locations. We evaluated the proposed method using 5-minute volumetric MRI time series with 340 ms temporal resolution collected from 7 liver carcinoma patients. The time series was acquired using golden-angle radial MRI sequence and reconstructed through retrospective sorting. Two MRI with inhale and exhale states respectively were selected from the first 30 sec of the time series for prior embedding and augmentation. The remaining 4.5-min time series was used for volumetric reconstruction evaluation, where we retrospectively subsampled each MRI to 2 orthogonal slices and compared network-reconstructed images to ground truth images in terms of image quality and the capability of supporting 3D target motion tracking.

RESULTS

Across the 7 patients evaluated, the peak signal to noise ratio between model reconstruction and ground truth was 54.66 ± 6.16 dB and the structural similarity index measure was 0.99 ± 0.01. Gross tumor volume (GTV) contours estimated by deforming a reference state MRI to model-reconstructed and ground truth MRI showed good consistency. The 95-percentile Hausdorff distance between GTV contours was 1.89 ± 1.13 mm, which is less than the voxel dimension. The mean GTV centroid position difference between ground truth and model estimation was less than 1 mm in all 3 orthogonal directions.

CONCLUSION

Volumetric MRI from orthogonal cine acquisition with sparse priors is feasible by modeling prior knowledge through implicit neural representation learning. The model-reconstructed images showed sufficient accuracy in supporting 3D motion tracking of abdominal targets. By eliminating the need for large scale training datasets, the method promises to enable clinical implementation of 3D motion tracking for precision radiation therapy.

P–724 The association between use of assisted reproductive techniques and childhood asthma: a Swedish nationwide register-based cohort study

Study question

Are the previously reported greater risks of childhood asthma in children conceived by assisted reproductive techniques due to the intervention or unmeasured parental confounding?

Summary answer

After accounting for both measured and unmeasured parental factors we found no indication that the use of assisted reproductive techniques increases children’s risk of asthma.

What is known already

Several earlier studies have reported a higher risk of childhood asthma among children conceived by ART. However, only one previous study has attempted a sibling comparison to account for infertility as well as parental background factors, and their findings need to be replicated. Little is thus known on what underlies the higher risk of childhood asthma.

Study design, size, duration

In this nationwide register-based cohort, we identified all 1,671,532 live births between 1997 and 2013 in the Swedish Medical Birth Register (MBR) and followed them to the end of 2018.

Participants/materials, setting, methods

Infertility and ART use were ascertained from IVF clinic reporting, clinical diagnosis, and maternal self-report during the first antenatal visit. Childhood asthma was identified from diagnosis in hospitalization and outpatient specialist care records, and dispensations of asthma medication. Cox proportional hazard regression was used to estimate the association of ART and asthma in the population, in children of couples with known infertility, and in a sample of siblings conceived with and without ART (differentially exposed).

Main results and the role of chance

Of the 1,671,532 live births in the cohort, 11.7% were born to couples with known infertility, and 3.5% were conceived with ART. Compared with all other children, children conceived by ART had a small, elevated risk of asthma (adjusted hazard ratio (aHR)=1.14, 95% Confidence interval (CI) 1.11 to 1.16). When the comparison was restricted to children of couples with known infertility the difference in risk was even smaller (aHR=1.07, 95% CI 1.05 to 1.10), and in the comparison of siblings conceived with and without ART no difference in risk was seen (aHR=0.98, 95% CI 0.86 to 1.13). Among children conceived with ART, those in which intra-cytoplasmic sperm injection (ICSI) had been used had a slightly lower risk of asthma (aHR=0.93, 95% CI 0.90 to 0.97), and no difference in risk was seen between use of fresh and frozen-thawed embryo transfer.

Limitations, reasons for caution

Sibling comparison is sensitive to potential misclassification, unmeasured confounding and carryover effects, so should be interpreted with this in mind. Differences in treatment implementation across time and settings could affect the ability to extrapolate the conclusions to another clinical context (where e.g., single-embryo transfer policy is not implemented).

Wider implications of the findings: This study found a modestly elevated risk of asthma in children conceived with ART to be largely explained by confounding from parental background factors. There were further no indications of adverse influence from increasingly utilized ART procedures such as ICSI or embryo-freezing, with respect to asthma in childhood.

Trial registration number

Not applicable

Range of motion in the talo-navicular and the calcaneo-cuboid joints evaluated by ultrasound during clubfoot treatment with normal references up to the age of four years

PURPOSE

Previous ultrasound studies of clubfeet have mainly focused on the first year of life. The purpose of this study was to improve the evaluation of the talo-navicular and calcaneo-cuboid joints by adding new variables, evaluating the repeatability of ultrasound measurements for normal feet and clubfeet and establishing values for normal feet up to four years of age.

METHODS

A control group of 105 children divided into ten age groups, and 71 clubfeet in 46 children were examined. Four new variables were introduced: medial malleolus-Talar head-Navicular distance, medial tangent of the talus to the medial border of the navicular distance, the angle between the longitudinal axis of the talus and a line from the centre of the talar head to the medial corner of the navicular, the angle between the lateral borders of the calcaneus and the cuboid. The mobility in the talo-navicular and the calcaneo-cuboid joints was assessed by comparing measurements with the foot in adduction and abduction.

RESULTS

The variables could be assessed with fair to very good intra- and inter-observer repeatability (intraclass correlation coefficient > 0.8 and ≥ 0.6, respectively), with a few exceptions. There was less movement in talo-navicular and calcaneo-cuboid joints in clubfeet than in controls.

CONCLUSION

Morphology of normal feet and clubfeet, as well as mobility in the talo-navicular and calcaneo-cuboid joints, can be assessed by ultrasound with a fair to very good reliability from birth to the age of four years.

LEVEL OF EVIDENCE

III.

The Quest for Welfare-Friendly Feeding of Broiler Breeders: Effects of Daily vs. 5:2 Feed Restriction Schedules

Restricted feeding of broiler breeders is required for improved long-term health and welfare. Because feeding frustration and hunger are major welfare concerns during rearing, many suggestions have been made to decrease the negative feelings of hunger while maintaining suitable growth rates and reproductive health. Non-daily ("skip-a-day") feeding schedules are commonly used around the world to increase portion sizes at meal times while restricting intake but these practices are prohibited in many countries due to welfare concerns on fasting days. We compared birds raised on a non-daily feeding schedule (2 non-consecutive fasting days per week, 5:2), previously suggested as a welfare-friendlier non-daily alternative, to birds raised on daily feed restriction. We found signs of increased physiological stress levels in 5:2 birds, including elevated heterophil to lymphocyte ratios (1.00 for 5:2 vs. 0.75 for daily fed at 12 weeks of age), increased adiposity (0.21% lean body weight [LBW] for 5:2 vs. 0.13% LBW for daily fed), and reduced muscle growth (pectoral muscle 5.94% LBW for 5:2 vs. 6.52% LBW for daily fed). At the same time, 5:2 birds showed signs of lower anxiety before feeding times (activity was reduced from 10.30 in daily fed to 4.85) which may be a result of the lower feed competition associated with larger portion sizes. Although we found no difference in latency to first head movement in tonic immobility between the treatments (136.5 s on average for both groups), 5:2 birds generally showed more interest in a novel object in the home pen which indicated increased risk taking and reduced fear while fasting. The 5:2 birds in this study showed no signs of learning the feeding schedule, and this unpredictability may also increase stress. Taken together, the effects of 5:2 vs. daily feed restriction on the welfare of broiler breeder pullets remain inconclusive and differ between feeding and fasting days. In addition to reducing stress by minimizing the number of fasting days, we suggest that a shift to more predictable schedules may help improve the welfare of broiler breeder pullets.

Coinfections identified from metagenomic analysis of cervical lymph nodes from tularemia patients

BACKGROUND

Underlying coinfections may complicate infectious disease states but commonly go unnoticed because an a priori clinical suspicion is usually required so they can be detected via targeted diagnostic tools. Shotgun metagenomics is a broad diagnostic tool that can be useful for identifying multiple microbes simultaneously especially if coupled with lymph node aspirates, a clinical matrix known to house disparate pathogens. The objective of this study was to analyze the utility of this unconventional diagnostic approach (shotgun metagenomics) using clinical samples from human tularemia cases as a test model. Tularemia, caused by the bacterium Francisella tularensis, is an emerging infectious disease in Turkey. This disease commonly manifests as swelling of the lymph nodes nearest to the entry of infection. Because swollen cervical nodes are observed from many different types of human infections we used these clinical sample types to analyze the utility of shotgun metagenomics.

METHODS

We conducted an unbiased molecular survey using shotgun metagenomics sequencing of DNA extracts from fine-needle aspirates of neck lymph nodes from eight tularemia patients who displayed protracted symptoms. The resulting metagenomics data were searched for microbial sequences (bacterial and viral).

RESULTS

F. tularensis sequences were detected in all samples. In addition, we detected DNA of other known pathogens in three patients. Both Hepatitis B virus (HBV) and Human Parvovirus B-19 were detected in one individual and Human Parvovirus B-19 alone was detected in two other individuals. Subsequent PCR coupled with Sanger sequencing verified the metagenomics results. The HBV status was independently confirmed via serological diagnostics, despite evading notice during the initial assessment.

CONCLUSION

Our data highlight that shotgun metagenomics of fine-needle lymph node aspirates is a promising clinical diagnostic strategy to identify coinfections. Given the feasibility of the diagnostic approach demonstrated here, further steps to promote integration of this type of diagnostic capability into mainstream clinical practice are warranted.

Assessment of the ankle joint in clubfeet and normal feet to the age of four years by ultrasonography

PURPOSE

To establish reproducible posterior ultrasonographic projections for evaluation of the movement in the talocrural joint in clubfeet and normal feet from the perinatal period up to the age of four years.

METHODS

The feet in 105 healthy children and 46 patients (71 clubfeet and 21 normal feet) were examined. In all, 14 feet in seven patients were examined twice by two examiners independently to evaluate the repeatability of the ultrasonography scans. A posterior sagittal projection was used. The distance from the posterior aspect of the tibial physis to the posterior border of the talocalcaneal joint (Tib. phys - TCJ) was measured with the foot in neutral position and dorsiflexion. In plantar flexion the shortest distance between the tibial physis and the calcaneus was measured. The distance from the skin to the tibial epiphyses and the talus was measured in neutral position. The intraclass correlation coefficient (ICC) was calculated to evaluate the repeatability of the measurements.

RESULTS

The interexaminer reliability was 0.71 to 0.89 ICC. The intra- and interobserver reliability measured as ICC was 0.68 to 0.99 for all measurements. The correlation between Tib. phys. - TCJ and clinical dorsiflexion varied much between the age groups.

CONCLUSION

Ultrasonography of the posterior aspect of the ankle joint can be done with high interexaminer reliability. The repeatability of image evaluation was high. Correlation to clinical measurements varied, therefore dynamic ultrasound in real time is clinically more useful than single measurements on frozen ultrasound images.

Translational Modeling to Guide Study Design and Dose Choice in Obesity Exemplified by AZD1979, a Melanin-concentrating Hormone Receptor 1 Antagonist

In this study, we present the translational modeling used in the discovery of AZD1979, a melanin‐concentrating hormone receptor 1 (MCHr1) antagonist aimed for treatment of obesity. The model quantitatively connects the relevant biomarkers and thereby closes the scaling path from rodent to man, as well as from dose to effect level. The complexity of individual modeling steps depends on the quality and quantity of data as well as the prior information; from semimechanistic body‐composition models to standard linear regression. Key predictions are obtained by standard forward simulation (e.g., predicting effect from exposure), as well as non‐parametric input estimation (e.g., predicting energy intake from longitudinal body‐weight data), across species. The work illustrates how modeling integrates data from several species, fills critical gaps between biomarkers, and supports experimental design and human dose‐prediction. We believe this approach can be of general interest for translation in the obesity field, and might inspire translational reasoning more broadly.

Immunoglobulin (Ig)G1 and IgG4 anti-cyclic citrullinated peptide (CCP) associate with shared epitope, whereas IgG2 anti-CCP associates with smoking in patients with recent-onset rheumatoid arthritis (the Swedish TIRA project)

Given the possible importance of anti-citrullinated peptide/protein antibodies (ACPA) for initiation and progression of rheumatoid arthritis (RA), extended knowledge about the different isotypes and subclasses is important. In the present study, we analysed the immunoglobulin (Ig)G subclasses regarding reactivity against cyclic citrullinated peptides (anti-CCP) among 504 clinically well-characterized patients with recent-onset RA in relation to smoking habits, shared epitope (SE) status and IgA and pan-IgG anti-CCP antibodies. All patients, regardless of pan-IgG anti-CCP status, were analysed for IgG1-4 CCP reactivity. Sixty-nine per cent were positive in any IgG anti-CCP subclass, and of these 67% tested positive regarding IgG1, 35% IgG2, 32% IgG3, and 59% IgG4 anti-CCP. Among ever-smokers the percentages of IgG2 anti-CCP (P = 0·01) and IgA anti-CCP (P = 0·002)-positive cases were significantly higher compared to never-smokers. A positive IgG anti-CCP subclass -negative cases. Combining SE and smoking data revealed that IgG1 and IgG4 anti-CCP were the IgG anti-CCP isotypes associated with expression of SE, although the lower number of patients positive for IgG2 or IgG3 anti-CCP could, however, have influenced the results. High levels of IgG2 anti-CCP were shown to correlate with expression of the 'non-SE' allele human leucocyte antigen (HLA)-DRB1*15. In conclusion, in this study we describe different risk factor characteristics across the IgG anti-CCP subclasses, where IgG2 appears similar to IgA anti-CCP regarding the predominant association with smoking, while IgG1 and IgG4 related more distinctly to the carriage of SE genes.

Titanium ions form particles that activate and execute interleukin-1β release from lipopolysaccharide-primed macrophages

BACKGROUND AND OBJECTIVE

Peri-implantitis is a destructive inflammatory process characterized by destruction of the implant-supporting bone. Inflammasomes are large intracellular multiprotein complexes that play a central role in innate immunity by activating the release of proinflammatory cytokines. Although inflammasome activation has previously been linked to periodontal inflammation, there is still no information on a potential association with peri-implantitis. The aim of this study was to examine cytotoxic and proinflammatory effects, including inflammasome activation, of metals used in dental implants, in an in vitro model, as well as from clinical tissue samples.

MATERIAL AND METHODS

Human macrophages were exposed to different metals [titanium (Ti), cobalt, chromium and molybdenum] in a cell-culture assay. Cytotoxicity was determined using the neutral red uptake assay. Cytokine secretion was quantified using an ELISA, and the expression of genes of various inflammasome components was analysed using quantitative PCR. In addition, the concentrations of interleukin-1β (IL-1β) and Ti in mucosal tissue samples taken in the vicinity of dental implants were determined using ELISA and inductively coupled plasma mass spectrometry, respectively.

RESULTS

Ti ions in physiological solutions stimulated inflammasome activation in human macrophages and consequently IL-1β release. This effect was further enhanced by macrophages that have been exposed to lipopolysaccharides. The proinflammatory activation caused by Ti ions disappeared after filtration (0.22 μm), which indicates an effect of particles. Ti ions alone did not stimulate transcription of the inflammasome components. The Ti levels of tissue samples obtained in the vicinity of Ti implants were sufficiently high (≥ 40 μm) to stimulate secretion of IL-1β from human macrophages in vitro.

CONCLUSION

Ti ions form particles that act as secondary stimuli for a proinflammatory reaction.

Abstract P1-07-22: Infectious disease hospitalization in breast cancer patients: Risk and impact on prognosis

Background: Infection-related hospitalizations are a serious complication in breast cancer patients, resulting in treatment delay, prolonged hospitalization and future morbidity and mortality. Little, however, is known about the actual risk, clinical characteristics and outcomes of infection-related hospitalizations in this patient population.

Methods: We conducted a prospective population-based study including 7071 women diagnosed with primary invasive non-metastatic breast cancer between 2001 and 2008 in the Stockholm-Gotland region (Sweden), with complete follow-up until 2010. Standardized incidence ratios (SIRs) for infection-related hospitalizations (overall and by site) were estimated using background rates from the general female population, matched on age and calendar period. Associations with clinical characteristics and breast cancer outcomes (breast cancer death, distant metastasis and locoregional recurrence) were analysed using flexible parametric survival models.

Results: During a medium follow-up of 5.3 years, 657 hospital admissions with infections were observed and 1,2 and 5-year cumulative risks were 3.4, 4.7 and 8.1% respectively. Rates of infection-related hospitalizations were increased compared to the general female population (SIR = 2.12; 95% CI = 1.96-2.29) and site-specific SIRs were most pronounced for sepsis (SIR = 3.65; 95% CI = 3.13-4.26) and skin infections (SIR = 2.93; 95% CI = 2.35-3.64). The overall risk of infections was highest during the first year (SIR = 5.06; 95% CI, 4.46-5.74), and recurrent disease contributed to the long-term risk observed. Older age at diagnosis, chemotherapy, axillary radiotherapy, comorbidities and markers of tumor aggressiveness (large tumors, estrogen receptor negative tumors and lymph node positive tumors) were independent predictors of infectious disease risk. Analyses evaluating the prognostic impact of infections revealed an independent effect on breast cancer death and distant metastasis, associations that were mainly driven by sepsis (HR = 4.53; 95% CI, 3.25-6.33 and 1.69; 95% CI, 1.04-2.79 respectively). No association was found with future risk of locoregional recurrence.

Conclusions: Physicians and patients should be aware of the risk of serious infections which persists beyond the initial treatment period. Infection-related hospitalizations are an independent marker of poor prognosis. Further research is needed to elucidate the role of sepsis in breast cancer progression.

Citation Format: Brand JS, Colzani E, Johansson A, Giesecke J, Clements M, Bergh J, Hall P, Czene K. Infectious disease hospitalization in breast cancer patients: Risk and impact on prognosis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-22.

Oral appliance treatment in moderate and severe obstructive sleep apnoea patients non-adherent to CPAP

The aim of this retrospective study was to evaluate the effect of individually adjusted custom‐made mandibular advancement device/oral appliance (OA) in treatment of patients with moderate and severe obstructive sleep apnoea (OSA), who were non‐adherent to continuous positive airway pressure (CPAP) therapy. During 2007‐2013, 116 patients with moderate (n = 82) and severe (n = 34) OSA non‐adherent to CPAP treatment were referred for dental management with an individually adjusted OA at a specialist sleep clinic. Ten of the participants (8·6%) were lost to follow‐up, leaving the data set to consist of 106 patients (71 men/35 women, mean age 57 year, range 28‐90). Nocturnal respiratory polygraphic recordings were performed at baseline and follow‐up. Average time between baseline polygraphy and follow‐up was 12 months. A successful OA treatment outcome was based on polygraphy at the follow‐up and divided into three groups: 1 = AHI <5; 2 = 5 ≤ AHI <10 and >50% reduction in baseline AHI; and 3. >50% reduction in baseline AHI. If there was a ≤ 50% reduction in baseline AHI at the follow‐up, the treatment was considered as a failure. The overall treatment success rate was 75%. There was no significant difference in success rates between patients in the moderate and severe categories (69% and 77%, respectively). Low oxygen saturation (SpO_{2 nadir)} had a high predictive value for OA treatment failure. OA treatment of patients non‐adherent to CPAP is efficient and especially promising for the severe OSA group who are at greatest risks for developing serious comorbidities, if left untreated.

Overcoming the obstacles of implementing infection prevention and control guidelines

Reasons for a successful or unsuccessful implementation of infection prevention and control (IPC) guidelines are often multiple and interconnected. This article reviews key elements from the national to the individual level that contribute to the success of the implementation of IPC measures and gives perspectives for improvement. Governance approaches, modes of communication and formats of guidelines are discussed with a view to improve collaboration and transparency among actors. The culture of IPC influences practices and varies according to countries, specialties and healthcare providers. We describe important contextual aspects, such as relationships between actors and resources and behavioural features including professional background or experience. Behaviour change techniques providing goal-setting, feedback and action planning have proved effective in mobilizing participants and may be key to trigger social movements of implementation. The leadership of international societies in coordinating actions at international, national and institutional levels using multidisciplinary approaches and fostering collaboration among clinical microbiology, infectious diseases and IPC will be essential for success.

Genomic analyses of Francisella tularensis strains confirm disease transmission from drinking water sources, Turkey, 2008, 2009 and 2012

Waterborne epidemics of tularaemia caused by Francisella tularensis are increasingly reported in Turkey. We have used whole genome sequencing to investigate if F. tularensis isolated from patients could be traced back to drinking water sources. Tonsil swabs from 33 patients diagnosed with oropharyngeal tularaemia in three outbreaks and 140 water specimens were analysed. F. tularensis subsp. holarctica was confirmed by microagglutination and PCR in 12 patients and five water specimens. Genomic analysis of three pairs of patient and water isolates from outbreaks in Sivas, Çorum, and Kocaeli showed the isolates to belong to two new clusters of the F. tularensis B.12 genetic clade. The clusters were defined by 19 and 15 single nucleotide polymorphisms (SNPs) in a multiple alignment based on 507 F. tularensis genomes. One synonymous SNP was chosen as a new canonical SNP (canSNP) for each cluster for future use in diagnostic assays. No SNP was identified between the genomes from the patient–water pair of isolates from Kocaeli, one SNP between the pair of isolates from Sivas, whereas the pair from Çorum differed at seven SNPs. These results illustrate the power of whole genome sequencing for tracing F. tularensis patient isolates back to their environmental source.

Phylogeographical pattern of Francisella tularensis in a nationwide outbreak of tularaemia in Norway, 2011

In 2011, a nationwide outbreak of tularaemia occurred in Norway with 180 recorded cases. It was associated with the largest peak in lemming density seen in 40 years. Francisella tularensis was isolated from 18 patients. To study the geographical distribution of F. tularensis genotypes in Norway and correlate genotype with epidemiology and clinical presentation, we performed whole genome sequencing of patient isolates. All 18 genomes from the outbreak carried genetic signatures of F. tularensis subsp. holarctica and were assigned to genetic clades using canonical single nucleotide polymorphisms. Ten isolates were assigned to major genetic clade B.6 (subclade B.7), seven to clade B.12, and one to clade B.4. The B.6 subclade B.7 was most common in southern and central Norway, while clade B.12 was evenly distributed between the southern, central and northern parts of the country. There was no association between genotype and clinical presentation of tularaemia, time of year or specimen type. We found extensive sequence similarity with F. tularensis subsp. holarctica genomes from high-endemic tularaemia areas in Sweden. Finding nearly identical genomes across large geographical distances in Norway and Sweden imply a life cycle of the bacterium without replication between the outbreaks and raise new questions about long-range migration mechanisms.

Phylogeographical pattern of Francisella tularensis in a nationwide outbreak of tularaemia in Norway, 2011

In 2011, a nationwide outbreak of tularaemia occurred in Norway with 180 recorded cases. It was associated with the largest peak in lemming density seen in 40 years. Francisella tularensis was isolated from 18 patients. To study the geographical distribution of F.tularensis genotypes in Norway and correlate genotype with epidemiology and clinical presentation,we performed whole genome sequencing of patient isolates. All 18 genomes from the outbreak carried genetic signatures of F. tularensis subsp. holarctica and were assigned to genetic clades using canonical single nucleotide polymorphisms. Ten isolates were assigned to major genetic clade B.6 (subclade B.7),seven to clade B.12, and one to clade B.4. The B.6 subclade B.7 was most common in southern and central Norway, while clade B.12 was evenly distributed between the southern, central and northern parts of the country. There was no association between genotype and clinical presentation of tularaemia, time of year or specimen type. We found extensive sequence similarity with F. tularensis subsp. holarctica genomes from high-endemic tularaemia areas in Sweden.Finding nearly identical genomes across large geographical distances in Norway and Sweden imply a life cycle of the bacterium without replication between the outbreaks and raise new questions about long-range migration mechanisms.

Dental status and self-assessed chewing ability in 70- and 80-year-old subjects in Sweden

The objective was to compare two cohorts of elderly people, 70 and 80 years old, with respect to dental status and self-assessed chewing ability. The hypotheses were as follows: (i) dental status is associated with self-assessed chewing ability; (ii) chewing ability is poorer among the 80- than the 70-year-old subjects. Identical questionnaires were in 2012 sent to all subjects born in 1942 and 1932, living in two Swedish counties. The response rate was 70.1% resulting in samples of 5697 70- and 2922 80-year-old subjects. Answers to questions on self-assessed chewing ability, dental status and some other factors have been analysed. Dental status varied but was in general good; 72% of the 70- and 60% of the 80-year-old subjects reported that they had all or only few missing teeth. Rate of edentulism was 3% and 7%, respectively. Removable partial dentures were reported by 6% and 10%, respectively, implant treatment by 13% in both cohorts. Self-assessed chewing ability was mostly good and correlated with the number of teeth (Spearman rho = 0.46). A majority of the edentulous subjects assessed their chewing ability as very or fairly good. Logistic regression showed that self-assessed chewing ability was significantly associated with a number of dental variables but also with general health. In conclusion, dental status was relatively good at both ages but somewhat poorer in the older cohort. Dental status, some other dental variables and being healthy were in both age groups significantly associated with self-assessed chewing ability.

Clinical Decision Making on Extensive Molar Restorations

Extensive loss of posterior tooth substance, which traditionally was restored with amalgam or indirect restorations, is more commonly being restored with resin-based composite restorations. Using a questionnaire, we aimed to survey dentists' clinical decision making when restoring extensive defects in posterior molar teeth. The questionnaire, which included questions on background information from the dentists, clinical cases with treatment options, and general questions about restoring extensive posterior defects, was sent to 476 dentists. The response rate was 59%. Multiple logistic regressions were used to investigate the different associations. Most of the respondents preferred a direct composite restoration when one cusp was missing, while indirect restorations were most preferred when replacing three or four cusps. Younger dentists and dentists working in the private sector had a greater tendency to choose an indirect technique compared with older colleagues. Generally, the most important influencing factor in clinical decision making was the amount of remaining tooth substance. Factors that appeared to be less important were dental advertisements, use of fluoride, and dietary habits. Female dentists perceived factors such as oral hygiene, patient requests, and economy to be more important than did their male colleagues.

Validity of the relativistic phase shift model for the extrinsic spin Hall effect in dilute metal alloys

Recently, a generalized relativistic phase shift model was proposed (Fedorovet al 2013 Phys. Rev. B 88 085116) for the description of the skew-scattering contribution to the spin Hall effect caused by impurities. Here, we inspect this model by means of a systematic comparison with the results of first-principles calculations performed for several metallic host systems with different substitutional impurities. It is found that for its proper application, the differences between impurity and host phase shifts should be used as input parameters. Generally, the model provides good qualitative agreement with ab initio results for hosts with a free-electron-like Fermi surface and a relatively weak spin-orbit coupling, but fails otherwise.

Proficiency of drug susceptibility testing of Mycobacterium tuberculosis against pyrazinamide: the Swedish experience

BACKGROUND

Pyrazinamide (PZA) is a key drug in the treatment of tuberculosis (TB), including multidrug-resistant TB. Drug susceptibility testing (DST) of Mycobacterium tuberculosis against PZA is not included in the World Health Organization's yearly proficiency testing. There is an increasing need to establish quality control of PZA DST.

OBJECTIVE

To evaluate the performance of PZA DST and to introduce a quality assurance system for the test in Sweden.

METHOD

Panels with PZA-susceptible and -resistant isolates were used in three rounds of proficiency testing in all five Swedish clinical TB laboratories and our reference laboratory. All laboratories used the MGIT 960 system. Minimum inhibitory concentrations (MICs) were determined and the pncA gene was sequenced to further characterise the 52 panel strains.

RESULTS

Good agreement was seen between the phenotypic PZA DST and pncA sequence data, and MIC determination confirmed high levels of resistance. However, in contrast to other drugs, for which correct proficiency test results were observed, specificity problems occurred for PZA DST in some laboratories.

CONCLUSIONS

In Sweden, using panel testing, differences were seen in the proficiency of TB laboratories in correctly identifying PZA susceptibility. Improved results were noted in the third round; PZA has therefore been included in yearly proficiency testing.

Early inflammatory response in soft tissues induced by thin calcium phosphates

The inflammatory response to titanium and hydroxyapatite (HA)-coated titanium in living tissue is controlled by a number of humoral factors, of which monocyte chemoattractant protein-1 (MCP-1) has been specifically linked to the recruitment of monocytes. These cells subsequently mature into tissue-bound macrophages. Macrophages adhering to the proteins adsorbed at the implant surface play a pivotal role in initiating the rejection or integration of the foreign material. Despite this, little is known about the initial inflammatory events that occur in soft tissues following the implantation of titanium and HA-coated titanium implants. In this study, circular discs of commercially pure titanium (c.p. Ti) with either a thin crystalline HA coating or amorphous HA coating or uncoated were implanted subcutaneously into rats. The implants were retrieved after 24 and 72 h. The lactate dehydrogenase (LD) activity, DNA content, expression of MCP-1, interleukin-10 (IL-10), tumor necrosis factor α (TNF-α), as well as monocyte and polymorphonuclear granulocyte counts in the exudate surrounding the implants were analyzed. There were significantly higher DNA and LD levels around the titanium implants at 24 h compared with HA-coated titanium. A rapid decrease in MCP-1 levels was observed for all the implants over the period of observation. No statistically significant differences were found between the two HA-coated implants. Our results suggest a difference in the early soft-tissue response to HA-coated implants when compared with titanium implants, expressed as a downregulation of inflammatory cell recruitment. This suggests that thin HA coatings are promising surfaces for soft tissue applications.

Interim analysis of long-term intraduodenal levodopa infusion in advanced Parkinson disease

BACKGROUND

This interim 12-month analysis is a part of an open-label, observational, prospective study on health outcomes and cost impact of levodopa/carbidopa intestinal gel (LCIG, Duodopa) in Parkinson disease (PD). The specific aim was to investigate clinical and health-related quality of life (HRQoL) effects in routine care.

METHODS

Unified PD rating scale (UPDRS) was the primary efficacy measurement. PD QoL questionnaire 39 (PDQ-39) assessed HRQoL. Subjects were assessed at baseline, ≥3 months after surgery, and then every 3 months.

RESULTS

Twenty-seven treatment-naïve subjects when started with LCIG showed a decrease in UPDRS score that was statistically significant throughout the year: UPDRS total score (mean ± SD), baseline = 52.1 ± 16.1, N = 27, month 0 (first visit; at least 3 months after permanent LCIG) = 43.1 ± 16.7, N = 27, P = 0.003; month 12 = 42.5 ± 22.6, n = 25, P = 0.017. PDQ-39 results also showed a tendency for improvement: PDQ-39 (mean ± SD), baseline = 33.6 ± 10.8, N = 27, month 0 = 27.1 ± 11.8, N = 27, P = 0.001; 12 months = 28.8 ± 12.8, n = 23, P = 0.126.

CONCLUSIONS

LCIG provides functional improvement beginning at first visit that is sustained for 12 months.

Alcohol and aggressive behavior in men--moderating effects of oxytocin receptor gene (OXTR) polymorphisms

We explored if the disposition to react with aggression while alcohol intoxicated was moderated by polymorphic variants of the oxytocin receptor gene (OXTR). Twelve OXTR polymorphisms were genotyped in 116 Finnish men [aged 18-30, M = 22.7, standard deviation (SD) = 2.4] who were randomly assigned to an alcohol condition in which they received an alcohol dose of 0.7 g pure ethanol/kg body weight or a placebo condition. Aggressive behavior was measured using a laboratory paradigm in which it was operationalized as the level of aversive noise administered to a fictive opponent. No main effects of the polymorphisms on aggressive behavior were found after controlling for multiple testing. The interactive effects between alcohol and two of the OXTR polymorphisms (rs4564970 and rs1488467) on aggressive behavior were nominally significant and remained significant for the rs4564970 when controlled for multiple tests. To the best of our knowledge, this is the first experimental study suggesting interactive effects of specific genetic variants and alcohol on aggressive behavior in humans.