Material properties of common suture materials in orthopaedic surgery

Suture materials in orthopaedic surgery are used for closure of wounds, repair of fascia, muscles, tendons, ligaments, joint capsules, and cerclage or tension band of certain fractures. The purpose of this study was to compare the biomechanical properties of eleven commonly used sutures in orthopaedic surgery. Three types of braided non-absorbable and one type of braided absorbable suture material with different calibers (n=77) underwent biomechanical testing for maximum load to failure, strain, and stiffness. All samples were tied by one surgeon with a single SMC (Seoul Medical Center) knot and three square knots. The maximum load to failure and strain were highest for #5 FiberWire and lowest for #0 Ethibond Excel (p<0.001). The stiffness was highest for #5 FiberWire and lowest for #2-0 Vicryl (p<0.001). In all samples, the failure of the suture material occurred at the knot There was no slippage of the knot in any of the samples tested. This data will assist the orthopaedic surgeon in selection and application of appropriate suture materials and calibers to specific tasks.

Secondary collisions revisited: real-world crash data and relationship to crash test criteria

Objectives: Previous research conducted in the late 1980s suggested that vehicle impacts following an initial barrier collision increase severe occupant injury risk. Now over 25years old, the data are no longer representative of the currently installed barriers or the present US vehicle fleet. The purpose of this study is to provide a present-day assessment of secondary collisions and to determine if current full-scale barrier crash testing criteria provide an indication of secondary collision risk for real-world barrier crashes. Methods: To characterize secondary collisions, 1,363 (596,331 weighted) real-world barrier midsection impacts selected from 13years (1997-2009) of in-depth crash data available through the National Automotive Sampling System (NASS) / Crashworthiness Data System (CDS) were analyzed. Scene diagram and available scene photographs were used to determine roadside and barrier specific variables unavailable in NASS/CDS. Binary logistic regression models were developed for second event occurrence and resulting driver injury. To investigate current secondary collision crash test criteria, 24 full-scale crash test reports were obtained for common non-proprietary US barriers, and the risk of secondary collisions was determined using recommended evaluation criteria from National Cooperative Highway Research Program (NCHRP) Report 350. Results: Secondary collisions were found to occur in approximately two thirds of crashes where a barrier is the first object struck. Barrier lateral stiffness, post-impact vehicle trajectory, vehicle type, and pre-impact tracking conditions were found to be statistically significant contributors to secondary event occurrence. The presence of a second event was found to increase the likelihood of a serious driver injury by a factor of 7 compared to cases with no second event present. The NCHRP Report 350 exit angle criterion was found to underestimate the risk of secondary collisions in real-world barrier crashes. Conclusions: Consistent with previous research, collisions following a barrier impact are not an infrequent event and substantially increase driver injury risk. The results suggest that using exit-angle based crash test criteria alone to assess secondary collision risk is not sufficient to predict second collision occurrence for real-world barrier crashes.

Transmission of Chlamydia trachomatis through sexual partnerships: a comparison between three individual-based models and empirical data

Chlamydia trachomatis is the most common bacterial sexually transmitted infection (STI) in many developed countries. The highest prevalence rates are found among young adults who have frequent partner change rates. Three published individual-based models have incorporated a detailed description of age-specific sexual behaviour in order to quantify the transmission of C. trachomatis in the population and to assess the impact of screening interventions. Owing to varying assumptions about sexual partnership formation and dissolution and the great uncertainty about critical parameters, such models show conflicting results about the impact of preventive interventions. Here, we perform a detailed evaluation of these models by comparing the partnership formation and dissolution dynamics with data from Natsal 2000, a population-based probability sample survey of sexual attitudes and lifestyles in Britain. The data also allow us to describe the dispersion of C. trachomatis infections as a function of sexual behaviour, using the Gini coefficient. We suggest that the Gini coefficient is a useful measure for calibrating infectious disease models that include risk structure and highlight the need to estimate this measure for other STIs.

Debris-flow activity in abandoned channels of the Manival torrent reconstructed with LiDAR and tree-ring data

Hydrogeomorphic processes are a major threat in many parts of the Alps, where they periodically damage infrastructure, disrupt transportation corridors or even cause loss of life. Nonetheless, past torrential activity and the analysis of areas affected during particular events remain often imprecise. It was therefore the purpose of this study to reconstruct spatio-temporal patterns of past debris-flow activity in abandoned channels on the forested cone of the Manival torrent (Massif de la Chartreuse, French Prealps). A Light Detecting and Ranging (LiDAR) generated Digital Elevation Model (DEM) was used to identify five abandoned channels and related depositional forms (lobes, lateral levees) in the proximal alluvial fan of the torrent. A total of 156 Scots pine trees (Pinus sylvestris L.) with clear signs of debris flow events was analyzed and growth disturbances (GD) assessed, such as callus tissue, the onset of compression wood or abrupt growth suppression. In total, 375 GD were identified in the tree-ring samples, pointing to 13 debris-flow events for the period 1931–2008. While debris flows appear to be very common at Manival, they have only rarely propagated outside the main channel over the past 80 years. Furthermore, analysis of the spatial distribution of disturbed trees contributed to the identification of four patterns of debris-flow routing and led to the determination of three preferential breakout locations. Finally, the results of this study demonstrate that the temporal distribution of debris flows did not exhibit significant variations since the beginning of the 20th century.

Common mechanisms of auditory hallucinations-perfusion studies in epilepsy

Auditory hallucinations (AH) occur in various neurological and psychiatric disorders. In psychosis, increased neuronal activity in the primary auditory cortex (PAC) contributes to AH. We investigated functional neuroanatomy of epileptic hallucinations by measuring cerebral perfusion in three patients with AH during simple partial status epilepticus. Hyperperfusion in the temporal lobe covering the PAC occurred in all patients. Our perfusion data support the hypothesis of PAC being a constituting element in the genesis of AH independent of their aetiology.

Acinetobacter baumannii isolates from pets and horses in Switzerland: molecular characterization and clinical data

OBJECTIVES: We investigated whether Acinetobacter baumannii isolates of veterinary origin shared common molecular characteristics with those described in humans. METHODS: Nineteen A. baumannii isolates collected in pets and horses were analysed. Clonality was studied using repetitive extragenic palindromic PCR (rep-PCR) and multilocus sequence typing (MLST). PCR and DNA sequencing for various beta-lactamase, aminoglycoside-modifying enzyme, gyrA and parC, ISAba1 and IS1133, adeR and adeS of the AdeABC efflux pump, carO porin and class 1/2/3 integron genes were performed. RESULTS: Two main clones [A (n = 8) and B (n = 9)] were observed by rep-PCR. MLST indicated that clone A contained isolates of sequence type (ST) ST12 (international clone II) and clone B contained isolates of ST15 (international clone I). Two isolates of ST10 and ST20 were also noted. Seventeen isolates were resistant to gentamicin, 12 to ciprofloxacin and 3 to carbapenems. Isolates of ST12 carried bla(OXA-66), bla(ADC-25), bla(TEM-1), aacC2 and IS1133. Strains of ST15 possessed bla(OXA-69), bla(ADC-11), bla(TEM-1) and a class 1 integron carrying aacC1 and aadA1. ISAba1 was found upstream of bla(ADC) (one ST10 and one ST12) and/or bla(OXA-66) (seven ST12). Twelve isolates of different STs contained the substitutions Ser83Leu in GyrA and Ser80Leu or Glu84Lys in ParC. Significant disruptions of CarO porin and overexpressed efflux pumps were not observed. The majority of infections were hospital acquired and in animals with predisposing conditions for infection. CONCLUSIONS: STs and the molecular background of resistance observed in our collection have been frequently described in A. baumannii detected in human patients. Animals should be considered as a potential reservoir of multidrug-resistant A. baumannii.

Does pet ownership in infancy lead to asthma or allergy at school age? Pooled analysis of individual participant data from 11 European birth cohorts

Objective To examine the associations between pet keeping in early childhood and asthma and allergies in children aged 6–10 years. Design Pooled analysis of individual participant data of 11 prospective European birth cohorts that recruited a total of over 22,000 children in the 1990s. Exposure definition Ownership of only cats, dogs, birds, rodents, or cats/dogs combined during the first 2 years of life. Outcome definition Current asthma (primary outcome), allergic asthma, allergic rhinitis and allergic sensitization during 6–10 years of age. Data synthesis Three-step approach: (i) Common definition of outcome and exposure variables across cohorts; (ii) calculation of adjusted effect estimates for each cohort; (iii) pooling of effect estimates by using random effects meta-analysis models. Results We found no association between furry and feathered pet keeping early in life and asthma in school age. For example, the odds ratio for asthma comparing cat ownership with “no pets” (10 studies, 11489 participants) was 1.00 (95% confidence interval 0.78 to 1.28) (I2 = 9%; p = 0.36). The odds ratio for asthma comparing dog ownership with “no pets” (9 studies, 11433 participants) was 0.77 (0.58 to 1.03) (I2 = 0%, p = 0.89). Owning both cat(s) and dog(s) compared to “no pets” resulted in an odds ratio of 1.04 (0.59 to 1.84) (I2 = 33%, p = 0.18). Similarly, for allergic asthma and for allergic rhinitis we did not find associations regarding any type of pet ownership early in life. However, we found some evidence for an association between ownership of furry pets during the first 2 years of life and reduced likelihood of becoming sensitized to aero-allergens. Conclusions Pet ownership in early life did not appear to either increase or reduce the risk of asthma or allergic rhinitis symptoms in children aged 6–10. Advice from health care practitioners to avoid or to specifically acquire pets for primary prevention of asthma or allergic rhinitis in children should not be given.

Common obesity risk alleles in childhood attention-deficit/hyperactivity disorder

Children with attention-deficit/hyperactivity disorder (ADHD) have a higher rate of obesity than children without ADHD. Obesity risk alleles may overlap with those relevant for ADHD. We examined whether risk alleles for an increased body mass index (BMI) are associated with ADHD and related quantitative traits (inattention and hyperactivity/impulsivity). We screened 32 obesity risk alleles of single nucleotide polymorphisms (SNPs) in a genome-wide association study (GWAS) for ADHD based on 495 patients and 1,300 population-based controls and performed in silico analyses of the SNPs in an ADHD meta-analysis comprising 2,064 trios, 896 independent cases, and 2,455 controls. In the German sample rs206936 in the NUDT3 gene (nudix; nucleoside diphosphate linked moiety X-type motif 3) was associated with ADHD risk (OR: 1.39; P = 3.4 × 10(-4) ; Pcorr  = 0.01). In the meta-analysis data we found rs6497416 in the intronic region of the GPRC5B gene (G protein-coupled receptor, family C, group 5, member B; P = 7.2 × 10(-4) ; Pcorr  = 0.02) as a risk allele for ADHD. GPRC5B belongs to the metabotropic glutamate receptor family, which has been implicated in the etiology of ADHD. In the German sample rs206936 (NUDT3) and rs10938397 in the glucosamine-6-phosphate deaminase 2 gene (GNPDA2) were associated with inattention, whereas markers in the mitogen-activated protein kinase 5 gene (MAP2K5) and in the cell adhesion molecule 2 gene (CADM2) were associated with hyperactivity. In the meta-analysis data, MAP2K5 was associated with inattention, GPRC5B with hyperactivity/impulsivity and inattention and CADM2 with hyperactivity/impulsivity. Our results justify further research on the elucidation of the common genetic background of ADHD and obesity.

Centennial mineral dust variability in high-resolution ice core data from Dome C, Antarctica

Ice core data from Antarctica provide detailed insights into the characteristics of past climate, atmospheric circulation, as well as changes in the aerosol load of the atmosphere. We present high-resolution records of soluble calcium (Ca2+), non-sea-salt soluble calcium (nssCa2+), and particulate mineral dust aerosol from the East Antarctic Plateau at a depth resolution of 1 cm, spanning the past 800 000 years. Despite the fact that all three parameters are largely dust-derived, the ratio of nssCa2+ to particulate dust is dependent on the particulate dust concentration itself. We used principal component analysis to extract the joint climatic signal and produce a common high-resolution record of dust flux. This new record is used to identify Antarctic warming events during the past eight glacial periods. The phasing of dust flux and CO2 changes during glacial-interglacial transitions reveals that iron fertilization of the Southern Ocean during the past nine glacial terminations was not the dominant factor in the deglacial rise of CO2 concentrations. Rapid changes in dust flux during glacial terminations and Antarctic warming events point to a rapid response of the southern westerly wind belt in the region of southern South American dust sources on changing climate conditions. The clear lead of these dust changes on temperature rise suggests that an atmospheric reorganization occurred in the Southern Hemisphere before the Southern Ocean warmed significantly.

The common G-allele of interleukin-18 single-nucleotide polymorphism is a genetic risk factor for atopic asthma. The SAPALDIA Cohort Study

BACKGROUND: IL-18 is a pleiotrophic cytokine involved in both, T-helper type 1 (Th1) and Th2 differentiation. Recently genetic variants in the IL-18 gene have been associated with increased risk of atopy and asthma. OBJECTIVE: To examine the relationship of a genetic, haplotype-tagging promotor variant -137G/C in the IL-18 gene with atopic asthma in a large, well-characterized and population-based study of adults. METHODS: Prospective cohort study design was used to collect interview and biological measurement data at two examination time-points 11 years apart. Multivariate logistic regression analysis was used to assess the association of genotype with asthma and atopy. RESULTS: The G-allele of the IL-18 promotor variant (-137G/C) was associated with a markedly increased risk for the prevalence of physician-diagnosed asthma with concomitant skin reactivity to common allergens. Stratification of the asthma cases by skin reactivity to common allergens revealed an exclusive association of IL-18 -137 G-allele with an increased prevalence of atopic asthma (adjusted odds ratio (OR): 3.63; 95% confidence interval: (1.64-8.02) for GC or GG carriers vs. CC carriers), and no according association with asthma and concomitant negative skin reactivity (adjusted OR: 1.13; 0.66-1.94). The interaction between IL-18 -137G/C genotype and positive skin prick test was statistically significant (P=0.029). None of 74 incident asthma cases with atopy at baseline exhibited the CC genotype. CONCLUSION: Our results strongly suggest that this variant of the IL-18 gene is an important genetic determinant involved in the development of atopic asthma.

Estimating Multiple Tumor Transition Rates Based on Data from Survival/Sacrifice Experiments

In this paper, we focus on the model for two types of tumors. Tumor development can be described by four types of death rates and four tumor transition rates. We present a general semi-parametric model to estimate the tumor transition rates based on data from survival/sacrifice experiments. In the model, we make a proportional assumption of tumor transition rates on a common parametric function but no assumption of the death rates from any states. We derived the likelihood function of the data observed in such an experiment, and an EM algorithm that simplified estimating procedures. This article extends work on semi-parametric models for one type of tumor (see Portier and Dinse and Dinse) to two types of tumors.

RANDOM EFFECTS MODELS IN A META-ANALYSIS OF THE ACCURACY OF DIAGNOSTIC TESTS WITHIN A GOLD STANDARD IN THE PRESENCE OF MISSING DATA

In evaluating the accuracy of diagnosis tests, it is common to apply two imperfect tests jointly or sequentially to a study population. In a recent meta-analysis of the accuracy of microsatellite instability testing (MSI) and traditional mutation analysis (MUT) in predicting germline mutations of the mismatch repair (MMR) genes, a Bayesian approach (Chen, Watson, and Parmigiani 2005) was proposed to handle missing data resulting from partial testing and the lack of a gold standard. In this paper, we demonstrate an improved estimation of the sensitivities and specificities of MSI and MUT by using a nonlinear mixed model and a Bayesian hierarchical model, both of which account for the heterogeneity across studies through study-specific random effects. The methods can be used to estimate the accuracy of two imperfect diagnostic tests in other meta-analyses when the prevalence of disease, the sensitivities and/or the specificities of diagnostic tests are heterogeneous among studies. Furthermore, simulation studies have demonstrated the importance of carefully selecting appropriate random effects on the estimation of diagnostic accuracy measurements in this scenario.

Analysis of gene order data supports vertical inheritance of the leukotoxin operon and genome rearrangements in the 5' flanking region in genus Mannheimia

BACKGROUND: The Mannheimia subclades belong to the same bacterial genus, but have taken divergent paths toward their distinct lifestyles. For example, M. haemolytica + M. glucosida are potential pathogens of the respiratory tract in the mammalian suborder Ruminantia, whereas M. ruminalis, the supposed sister group, lives as a commensal in the ovine rumen. We have tested the hypothesis that vertical inheritance of the leukotoxin (lktCABD) operon has occurred from the last common ancestor of genus Mannheimia to any ancestor of the diverging subclades by exploring gene order data. RESULTS: We examined the gene order in the 5' flanking region of the leukotoxin operon and found that the 5' flanking gene strings, hslVU-lapB-artJ-lktC and xylAB-lktC, are peculiar to M. haemolytica + M. glucosida and M. granulomatis, respectively, whereas the gene string hslVU-lapB-lktC is present in M. ruminalis, the supposed sister group of M. haemolytica + M. glucosida, and in the most ancient subclade M. varigena. In M. granulomatis, we found remnants of the gene string hslVU-lapB-lktC in the xylB-lktC intergenic region. CONCLUSION: These observations indicate that the gene string hslVU-lapB-lktC is more ancient than the hslVU-lapB-artJ-lktC and xylAB-lktC gene strings. The presence of (remnants of) the ancient gene string hslVU-lapB-lktC among any subclades within genus Mannheimia supports that it has been vertically inherited from the last common ancestor of genus Mannheimia to any ancestor of the diverging subclades, thus reaffirming the hypothesis of vertical inheritance of the leukotoxin operon. The presence of individual 5' flanking regions in M. haemolytica + M. glucosida and M. granulomatis reflects later genome rearrangements within each subclade. The evolution of the novel 5' flanking region in M. haemolytica + M. glucosida resulted in transcriptional coupling between the divergently arranged artJ and lkt promoters. We propose that the chimeric promoter have led to high level expression of the leukotoxin operon which could explain the increased potential of certain M. haemolytica + M. glucosida strains to cause a particular type of infection.

International registry on factor XIII deficiency: a basis formed mostly on European data

FXIII deficiency is known as one of the rarest blood coagulation disorders. In this study, the phenotypic and in part genotypic data of 104 FXIII-deficient patients recorded from 1993 - 2005 are presented. The most common bleeding symptoms were subcutaneous bleeding (57%) followed by delayed umbilical cord bleeding (56%), muscle hematoma (49%), hemorrhage after surgery (40%), hemarthrosis (36%), and intracerebral bleeding (34%). Prophylactic treatment was initiated in about 70% of all patients. FXIII-B subunit-deficient patients had a milder phenotype than patients with FXIII-A subunit deficiency. The most frequent mutation affecting the F13A gene was a splice site mutation in intron 5 (IVS5-1G>A). This mutation was found in eight (17%) of 46 analyzed families. The haplotype analysis of patients carrying the IVS5-1A allele was consistent with a founder effect. The international registry (http://www.f13-database.de) will provide clinicians and scientists working on FXIII deficiency with a helpful tool to improve patient care and direct future studies towards better understanding and treatment of the disease.

An integrated approach for reconstructing surface models of the proximal femur from sparse input data for surgical navigation

A patient-specific surface model of the proximal femur plays an important role in planning and supporting various computer-assisted surgical procedures including total hip replacement, hip resurfacing, and osteotomy of the proximal femur. The common approach to derive 3D models of the proximal femur is to use imaging techniques such as computed tomography (CT) or magnetic resonance imaging (MRI). However, the high logistic effort, the extra radiation (CT-imaging), and the large quantity of data to be acquired and processed make them less functional. In this paper, we present an integrated approach using a multi-level point distribution model (ML-PDM) to reconstruct a patient-specific model of the proximal femur from intra-operatively available sparse data. Results of experiments performed on dry cadaveric bones using dozens of 3D points are presented, as well as experiments using a limited number of 2D X-ray images, which demonstrate promising accuracy of the present approach.