Assessment of pediatric shoulder range of motion and loading response to evaluate the biofidelity of the Large Omni-directional Child (LODC) anthropomorphic test device (ATD) shoulder design

The shoulder girdle complex, through engagement with the seat belt, influences motor vehicle occupant upper body movement during frontal impacts, affecting the movement of the head and spine. The recently developed Large Omni-directional Child (LODC) anthropomorphic test device (ATD) was designed with flexible shoulder girdle structures that capture the unique kinematics in pediatric occupants. However, the LODC shoulder has not been evaluated for biofidelity due to the lack of biomechanical data available on pediatric shoulder responses. This study evaluated quasi-static pediatric shoulder girdle complex responses through non-invasive displacement measurements. These data were obtained to evaluate, and, if necessary, improve the biofidelity of the LODC ATD. Shoulder range of motion and anthropometric measurements were obtained from 25 pediatric volunteers, ages 8-12 years old. Loads were applied bilaterally exclusively to the shoulder complexes in increments of 25 N up to 150 N per shoulder at 90 and 135 degrees of shoulder flexion. Still photos were used to determine shoulder displacement in the sagittal plane from images captured prior to and following the load applications. Data analysis consisted of motion tracking to evaluate the absolute and relative displacement of the right acromion and T1. The displacements for each volunteer were normalized based on the volunteer's shoulder width compared to the shoulder width of the LODC ATD. For the 90° load, the acromion moved relative to T1 an average of 28.1 mm forward and 3.1 mm downward at maximum displacement. For the 135° load, the acromion moved relative to T1 an average of 15.5 mm forward and 42.7 mm upward at maximum displacement. Similar displacements at higher loads indicated that the volunteers achieved their maximum range of motion. The results of this study will be compared to the LODC ATD, assessing the biofidelity of the shoulder complex.

Effect of naturalistic seating postures and seatbelt routing on booster-seated Q6 ATD kinematics and kinetics in frontal impacts

RESEARCH QUESTIONS / OBJECTIVE

Test protocols evaluate restraint performance with pediatric ATDs placed in an ideal seating posture. However, real-world evidence suggests that ideal test conditions do not always reflect actual occupant positions. Prior studies have also shown that booster seat designs affect the position of the seatbelt around the child. Occupants in naturalistic seating postures, coupled with potentially unfavorable seatbelt positions, could result in adverse kinematics and kinetics in a crash. Therefore, the aim of this study was to quantify the effect of different naturalistic seating postures on the response of the Q6 ATD restrained on boosters with varying initial static belt fit in a frontal impact.

METHODS/DATA SOURCES

The Q6 ATD was positioned on two booster seats of similar design but varying static belt fit metrics in three seating postures: reference, leaning forward, and leaning inboard. These booster seats were chosen from extensive belt fit studies on human volunteers and ATDs, and were defined as follows:The booster-seated ATD was restrained on the simulated Consumer Reports test buck (2010 Ford Flex 2nd row seat) with a front blocker plate using a 3-point lap-shoulder belt with a retractor and pretensioner. The sled environment was subjected to the FMVSS 213 frontal impact pulse, and each booster and seating posture was evaluated twice (n = 12 sled tests). Kinematic and kinetic measures were recorded. A linear regression analysis was conducted across postures on each booster. Further, a paired t-test analysis was conducted across booster seats for each seating posture.

RESULTS

Across seating postures, the reference posture exhibited similar or higher kinematic and kinetic metric values compared to the leaning forward and leaning inboard postures on both boosters. However, both leaning forward (Booster A = 279.5 ± 21.6 mm; Booster B = 298.8 ± 1.5 mm) and leaning inboard (Booster A = 308.7 ± 1.1 mm; Booster B = 331.4 ± 8.5 mm) postures generally resulted in greater head excursion than the reference posture (Booster A = 285.0 ± 16.9 mm; Booster B = 288.1 ± 1.5 mm), indicating greater potential for head contact. Between boosters, Booster A resulted in significantly lower head 3 ms clip acceleration (p = 0.0026), HIC15 (p = 0.0008), upper neck tensile force (F_z)(p = 0.0057), chest 3 ms clip acceleration (p = 0.0013), and right abdominal pressure (p = 0.0163), and significantly higher left ASIS force (F_x)(p = 0.0150) and left (p = 0.0489) and right (p = 0.0088) ASIS moment (M_y) than Booster B. Upper neck tensile forces on Booster B crossed the 20% and 50% thresholds for AIS3 + injury. Lower abdominal pressure and higher ASIS forces and moments on Booster A suggest that the lap belt loaded the ASIS appropriately, and hence, relatively better kinematics than Booster B.

SIGNIFICANCE OF RESULTS

This study shows that booster design affects static belt fit which can have an effect on dynamic crash performance and assessment criteria. By connecting static belt fit to dynamic performance, these effects may have the potential to help guide booster seat design.

POS0842 NON-INVASIVE COHERENT RAMAN IMAGING OF INVOLVED FOREARM SKIN REVEALS ALIGNED COLLAGEN IN DERMIS OF SYSTEMIC SCLEROSIS PATIENTS

Background

Systemic sclerosis (SSc) is an immune-mediated connective tissue disease with clinical hallmark of inflammation, vasculopathy and fibrosis resulting in abnormal collagen and intercellular matrix formation in the dermis and internal organ. Skin severity correlates with systemic complications and mortality in SSc.

Many skin assessment tools studied do not fulfilled all standards set by OMERACT which include criterion validity, construct validity, discrimination, responsiveness, reliability and feasibility.

Modified Rodnan skin score (mRSS) is commonly used as outcome measure in clinical trials of SSc. It is however, limited by inter-rater variability. Studies also showed that skin biopsy samples from body part of SSc patients with clinically normal mRSS had demonstrable pathological deposition of collagen. While repeat skin biopsy to track longitudinally, may be unacceptable to patients. Hence, ongoing research for non-invasive tools are encouraged.

Objectives

We follow through our previous work studying commercially available non-invasive imaging tools in SSc skin assessment by using Coherent-Raman scattering microscopy (CRS).

Methods

Skin biopsies of 4mm were obtained from SSc (n=3) and HC (n=1). Skin samples were collected at anterior surface of forearm from newly diagnosed diffuse SSc which were treatment naïve. Samples were frozen at -80c prior to analysis under CRS at skin depth of 150-200um. The laser setting was 3% pump (802nm) and 6% stokes (1045nm) to avoid tissue burn. 3 contrast methods used are Coherent anti-Stokes Raman scattering (CARS) for imaging of lipids, Second Harmonic Generation (SHG) for collagen and Two-Photon Fluorescence (TPF) for elastin fibers. We analysed collagen and elastin fibers in the skin samples which is disease relevant end products of fibroblast activation in SSc. Descriptive study of the skin CRS characteristics is reported.

Results

The SHG analysis revealed denser collagen fibers in dermal layer of diseased skin. It also appears that the collagen deposition occurs in more superficial layers of the skin. Peak of collagen curve were at depth of 110-130um HC vs 75-90um in SSc. Collagen fibres were more aligned in the SSc (Figure 1).

Figure 1.

Microscopy analysis of SSc (B) vs HC (A) skin. I: 3D image of biopsy samples with three contrasts. Red is CARS for lipid, blue is SHG for collagen and green is TPF for elastin fibers. II. SHG. Imaging revealed denser and more aligned collagen fibers in SSc.

Furthermore, TPF revealed larger number of disordered elastin fibres in the dermal layer of SSc than HC.

Conclusion

Nailfold capillaroscopy is used to define and stage micro-vasculopathy in SSc. Inflammatory pro-fibrotic processes on the other hand cause abnormal collagen and intercellular matrix formation in the dermis and internal organ.

With the demand of better tools in diagnosis of early SSc and therapeutic research, our work with CRS prove better in objective evaluation of skin changes at the molecular level. Here, we demonstrate that the SHG is altered in the early diffuse SSc skin with increased and aligned collagen in the SSc dermis compatible with mRSS score. Others have observed this alignment of the collagen, and we have published that SSc fibroblasts migrate/invade along aligned collagen and modify the underlying extracellular matrix, adding collagens I and III, cross-linking enzymes and other factors including TSP-1.

Our future work include:

1.Generating a computer module in defining pathological collagen level

2.Analysis of metabolites and pathological pathways in SSc

3.In-vivo trials with novel therapeutic peptides.

4.Lastly, manufacturing of non-invasive handheld device that is capable of diagnosis subclinical SSc and for outcome measure in clinical-therapeutic research

References

[1]Abignano G, et al. Virtual skin biopsy by optical coherence tomography: the first quantitative imaging biomarker for scleroderma. Ann Rheum Dis. 2013

[2]Ahmed Abdi B, et.al. Use of Patterned Collagen Coated Slides to Study Normal and Scleroderma Lung Fibroblast Migration. Sci Rep. 2017

Acknowledgements

We want to acknowledge our colleagues and patients in Royal Free Hospital, to make this project a success.

Disclosure of Interests

None declared

417 Vibrational Spectroscopy: A Rapid Tool for Soft Tissue Sarcoma Assessment

Aim

Soft tissue sarcomas (STS) are a comparatively unusual cluster of tumours; they arise from mesenchymal tissues. Surgery remains the primary and the only potentially curative treatment for most STS subtypes.

Existing intraoperative margin assessment techniques are inadequate and the current gold standard for resection margin assessment of STS is post-operative histopathology, but this takes weeks to finalize. Consequently, an augmented surgical technique established by real-time non-destructive recognition of clear margins is essential to diminish the risk of local relapse, decrease the resection area, and enhance the effectiveness of surgical resection of STS.

Vibrational spectroscopy (VS) is a non-destructive evaluation of the atomic oscillation within a molecule. Every molecule has a unique set of vibrational modes called molecular fingerprint. We aim to use Raman spectroscopy to analyse biomolecular spectra of sarcoma and develop a potential tool for intra operative margin assessment

Method

Human sarcoma was tissue obtained from the biobank at QEHB. The samples were identified as Lipoma and Liposarcoma. The samples underwent spectral measurement with the Raman microscope and the tissue samples were then sent for histopathological analysis.

Results

The spectral evaluation clearly demonstrates the biomolecular difference between the two groups and has a potential to become an intraoperative tool.

Conclusions

A positive resection margin is the ultimate prognosticator of local relapse. There is a need for a rapid and reliable tool that can offer surgeons with instant feedback during primary procedure.

Characterization of the motion of booster-seated children during simulated in-vehicle precrash maneuvers

Objective: Precrash occupant motion may affect head and trunk position and restraint performance in a subsequent crash, particularly for young children. Others have studied seat belt-restrained adult drivers and adult and adolescent passengers in precrash maneuvers. For younger children, optimal restraint includes a belt-positioning booster seat, which in precrash maneuvers may contribute in unique ways to the overall body motion. Therefore, the objective of this study was to quantify booster-seated child occupant kinematic, kinetic, and muscle responses during precrash maneuvers and characterize booster movement with respect to the overall occupant kinematics.Methods: Vehicle maneuver tests were conducted with a recent model year sedan at the Transportation Research Center Inc. (TRC, Marysville, Ohio). Three precrash vehicle maneuvers were simulated: Automated and manual emergency braking (AEB and MEB) and oscillatory swerving or slalom (SLA). Each maneuver was repeated twice for each participant. Seven 6- to 8-year-old booster-seated children participated in the study and all subjects were seated in the right rear seat. Vehicle dynamics (i.e., motion, position, and orientation) were measured with an inertial and Global Positioning System navigation system (Oxford RT 3003). Kinematic data from human volunteers were collected with an 8-camera 3D motion capture system (Optitrack Prime 13 200 Hz, NaturalPoint, Inc.). Photoreflective markers were placed on participants' head and trunk. Electromyography (EMG; Trigno EMG Wireless Delsys, Inc., 2,000 Hz) sensors were placed on bilateral muscles predicted to be most likely involved in bracing behaviors.Results: Children demonstrated greater head and trunk velocity in MEB (head 123.7 ± 13.1 cm/s, trunk 77.6 ± 14.1 cm/s) compared to AEB (head 45.31 ± 11.5 cm/s, trunk 27.1 ± 5.5 cm/s; P < .001). Participants also showed greater head motion in MEB (18.9 ± 1.4 cm) vs. AEB (15.1 ± 4.8 cm) but the differences were not statistically significant (P < .1). Overall, the booster seats themselves did not move substantially (<3 cm) in the braking maneuvers. During the SLA, however, the booster seat moved laterally up to 5 cm in several subjects, contributing substantially to peak trunk (6.5-14.0 cm) and head (9.9-21.4 cm) excursion during the maneuver. Booster-seated children also exhibited a greater activation of biceps and deltoid muscles and abdominal and middle trapezii muscles than the sternocleidomastoids during these maneuvers.Conclusions: The quantification of booster seat motion and neuromuscular control and the relationship between kinematics and muscle activation in booster-seated children in precrash maneuvers provides important data on the transition between the precrash and crash phases for this young age group and may help identify opportunities for interventions that integrate active and passive safety.

Effect of automated versus manual emergency braking on rear seat adult and pediatric occupant precrash motion

Objective: Emergency braking can potentially generate precrash occupant motion that may influence the effectiveness of restraints in the subsequent crash, particularly for rear-seated occupants who may be less aware of the impending crash. With the advent of automated emergency braking (AEB), the mechanism by which braking is achieved is changing, potentially altering precrash occupant motion. Further, due to anatomical and biomechanical differences across ages, kinematic differences between AEB and manual emergency braking (MEB) may vary between child and adult occupants. Therefore, the objective of this study was to quantify differences in rear-seated adult and pediatric kinematics and muscle activity during AEB and MEB scenarios. Methods: Vehicle maneuvers were performed in a recent model year sedan traveling at 50 km/h. MEB (acceleration ∼1 g) was achieved by the driver pressing the brake pedal with maximum effort. AEB (acceleration ∼0.8 g) was triggered by the vehicle system. Inertial and Global Positioning System data were collected. Seventeen male participants aged 10-33 were restrained in the rear right passenger seat and experienced each maneuver twice. The subjects' kinematics were recorded with an 8-camera 3D motion capture system. Electromyography (EMG) recorded muscle activity. Head and trunk displacements, raw and normalized by seated height, and peak head and trunk velocity were compared across age and between maneuvers. Mean EMG was calculated to interpret kinematic findings. Results: Head and trunk displacement and peak velocity were greater in MEB than in AEB in both raw and normalized data (P ≤ .01). No effect of age was observed (P ≥ .21). Peak head and trunk velocities were greater in repetition 1 than in repetition 2 (P ≤ .006) in MEB but not in AEB. Sternocleidomastoid (SCM) mean EMG was greater in MEB compared to AEB, and muscle activity increased in repetition 2 in MEB. Conclusions: Across all ages, head and trunk excursions were greater in MEB than AEB, despite increased muscle activity in MEB. This observation may suggest an ineffective attempt to brace the head or a startle reflex. The increased excursion in MEB compared to AEB may be attributed to differences in the acceleration pulses between the 2 scenarios. These results suggest that AEB systems can use specific deceleration profiles that have potential to reduce occupant motion across diverse age groups compared to sudden maximum emergency braking applied manually.

A protein-truncating R179X variant in RNF186 confers protection against ulcerative colitis

Protein-truncating variants protective against human disease provide in vivo validation of therapeutic targets. Here we used targeted sequencing to conduct a search for protein-truncating variants conferring protection against inflammatory bowel disease exploiting knowledge of common variants associated with the same disease. Through replication genotyping and imputation we found that a predicted protein-truncating variant (rs36095412, p.R179X, genotyped in 11,148 ulcerative colitis patients and 295,446 controls, MAF=up to 0.78%) in RNF186, a single-exon ring finger E3 ligase with strong colonic expression, protects against ulcerative colitis (overall P=6.89 × 10(-7), odds ratio=0.30). We further demonstrate that the truncated protein exhibits reduced expression and altered subcellular localization, suggesting the protective mechanism may reside in the loss of an interaction or function via mislocalization and/or loss of an essential transmembrane domain.

Thiopurine withdrawal during sustained clinical remission in inflammatory bowel disease: relapse and recapture rates, with predictive factors in 237 patients

BACKGROUND

Thiopurines (azathioprine and mercaptopurine) remain integral to most medical strategies for maintaining remission in Crohn's disease (CD) and ulcerative colitis (UC). Indefinite use of these drugs is tempered by long-term risks. While clinical relapse is noted frequently following drug withdrawal, there are few published data on predictive factors.

AIM

To investigate the success of planned thiopurine withdrawal in patients in sustained clinical remission to identify rates and predictors of relapse.

METHODS

This was a multicentre retrospective cohort study from 11 centres across the UK. Patients included had a definitive diagnosis of IBD, continuous thiopurine use ≥3 years and withdrawal when in sustained clinical remission. All patients had a minimum of 12 months follow-up post drug withdrawal. Primary and secondary end points were relapse at 12 and 24 months respectively.

RESULTS

237 patients were included in the study (129 CD; 108 UC). Median duration of thiopurine use prior to withdrawal was 6.0 years (interquartile range 4.4-8.4). At follow-up, moderate/severe relapse was observed in 23% CD and 12% UC patients at 12 months, 39% CD and 26% UC at 24 months. Relapse rate at 12 months was significantly higher in CD than UC (P = 0.035). Elevated CRP at withdrawal was associated with higher relapse rates at 12 months for CD (P = 0.005), while an elevated white cell count was predictive at 12 months for UC (P = 0.007).

CONCLUSION

Thiopurine withdrawal in the context of sustained remission is associated with a 1-year moderate-to-severe relapse rate of 23% in Crohn's disease and 12% in ulcerative colitis.

Diets containing inulin but not lupins help to prevent swine dysentery in experimentally challenged pigs

Swine dysentery is a contagious mucohemorrhagic diarrheal disease caused by the intestinal spirochete Brachyspira hyodysenteriae that colonizes and induces inflammation of the cecum and colon. It has been reported that a diet containing chicory root and sweet lupin can prevent swine dysentery. This experiment was conducted to test the hypothesis that inulin in the chicory root rather than galactans in lupins was responsible for protective effects. An experiment with a 2 × 2 factorial arrangement of treatments was undertaken using pigs fed barley- and triticale-based diets, with the main effects being protein source [185 g/kg of canola meal (decreased galactans) or 220 g/kg of lupins (greater galactans)] and inulin supplementation (0 or 80 g/kg). Forty Large White × Landrace pigs weighing 21 ± 3 kg, with 10 pigs per diet, were allowed to adapt to the diets for 2 wk, and then each pig was challenged orally 4 times with a broth culture containing B. hyodysenteriae on consecutive days. Pigs were killed when they showed clinical signs of dysentery or 6 wk postchallenge. Pigs fed diets without inulin had 8.3 times greater risk (P = 0.017) of developing swine dysentery and were 16 times more likely (P = 0.004) to have colon contents that were culture-positive for B. hyodysenteriae, compared with the pigs fed a diet with 80 g/kg of inulin. Diets containing lupins did not prevent pigs from developing clinical swine dysentery; however, inclusion of lupins or inulin or both in the diets delayed the onset of disease compared with the diet based mainly on canola meal (P < 0.05). Diet did not influence the total concentration of organic acids in the ileum, cecum, or upper and lower colon; however, the molar proportions of the organic acids were influenced (P < 0.05). Consequently the pH values in the cecum, and upper and lower colon were not influenced (P > 0.05) by diet. However the pH values of the ileal digesta were decreased in pigs fed the diet with both lupins and inulin compared with the diet containing only lupins (P < 0.05). In conclusion, this study shows that diets supplemented with highly fermentable carbohydrates from inulin protected pigs against developing swine dysentery.

How good is zoom endoscopy for assessment of villous atrophy in coeliac disease?

BACKGROUND AND STUDY AIMS

The advent of magnification endoscopy may allow the macroscopic detection of unrecognised villous atrophy in patients with unsuspected coeliac disease. In addition, it may also be possible to use this method to assess the degree of villous atrophy. The aim of this study was to determine the accuracy of zoom endoscopy for the macroscopic evaluation of villous atrophy, in comparison with histological evaluation.

PATIENTS AND METHODS

The zoom endoscope provided a magnification capability of x 115. A scoring system (Z score) was devised for grading the appearances of villous atrophy: "Z1" for normal mucosa, "Z2" for stunted villi, "Z3" for markedly stunted villi (with ridges and pits) and "Z4" for a flat mucosa. A total of 53 consecutive patients with treated coeliac disease were followed up over almost 2 years using the Olympus GIF-Q240Z zoom endoscope; a total of 80 procedures were carried out. Four biopsies from the second part of the duodenum were taken from each patient for histological assessment. Histological assessment of villous atrophy was made by a pathologist blinded to the Z score. The correlation between the Z score and the histological score was assessed using the weighted kappa method.

RESULTS

The kappa score for the correlation between the macroscopic assessment of villous atrophy and the histology was 0.631, indicating fair to good reproducibility. Agresti's method revealed a very strong baseline association between the two methods ( P < 0.001). Zoom endoscopy had a positive predictive value of 83 % and a negative predictive value of 77 % in detecting villous atrophy.

CONCLUSIONS

Our findings suggest that zoom endoscopy may be valuable in assessing the degree of villous atrophy. However, further studies are needed to assess its efficacy in routine practice as a screening or case-finding tool.

Conducting population behavioral health surveillance by using automated diagnostic and pharmacy data systems

INTRODUCTION

The Walter Reed Army Institute of Research used the Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE) to conduct population-based behavioral health surveillance among military-health-system beneficiaries. The study analyzed the effectiveness of using prescribing patterns of psychotropic medications to monitor changes in a community's behavioral health status.

OBJECTIVES

The objectives of this study were to 1) determine the feasibility of tracking psychiatric illnesses by monitoring prescriptions for psychiatric medications; 2) assess how often psychiatric medications are prescribed for patients with no record of psychiatric illness; 3) determine at what types of clinics these medications are prescribed most often and what other diagnoses are attributed to these patients; and 4) analyze data for potential changes in the population's mental health after high-stress events.

METHODS

Correlation analysis and calculations of sensitivity and specificity were used to determine how well prescription medications correlate with outpatient diagnoses and how well they serve as proxies for outpatient diagnoses. A descriptive analysis was conducted of the types of clinics (e.g., primary care, behavioral health, or other specialty clinics) treating patients and the associated percentage of concurrence between prescriptions and diagnostic codes.

RESULTS

In military treatment facilities, a diagnosis of depression or anxiety correlated significantly (r = 0.82) with antidepressant or anxiolytic prescriptions. Sensitivity of prescriptions when compared with outpatient visits was 0.76, and specificity was 0.94. Among those patients who visited a primary care clinic either the day before or the same day as an antidepressant or anxiolytic prescription was filled, 60.1% did not receive a diagnosis of any mental health disorder. Behavioral health clinics had the highest correlation between diagnoses and prescriptions; specialty clinics had the lowest.

CONCLUSIONS

Behavioral health trends in a population can be monitored by automated analysis of prescribing patterns alone. This method might be a rapid indicator of needed mental health interventions after acute stress-inducing events and be more sensitive than tracking diagnoses alone.

Genetic variation at the chromosome 16 chemokine gene cluster: development of a strategy for association studies in complex disease

The chemokine gene cluster [CCL22, CX3CL1, CCL17] (previously known as [SCYA22, SCYD1, SCYA17]) is a candidate locus for one of the susceptibility genes for inflammatory bowel disease that are located in the peri-centromeric region of chromosome 16. Screening for sequence variation at this locus led to the detection of 14 single nucleotide polymorphisms (SNPs). An efficient experimental and computational approach was developed to estimate allele frequencies and pairwise linkage disequilibrium relationships between SNPs at this locus, and to test them for association with inflammatory bowel disease. The 12 common SNPs were assigned to 5 distinct linkage disequilibrium groups. Genotyping of one SNP from each linkage disequilibrium group in a large cohort of families with inflammatory bowel disease did not provide convincing evidence of association with either Crohn's disease or ulcerative colitis. We describe an efficient experimental design from SNP screening to association testing. This strategy can be used to test candidate genes for involvement in susceptibility to complex disease.

Genetic variation in the IGSF6 gene and lack of association with inflammatory bowel disease

The immunoglobulin superfamily 6 gene (IGSF6) on chromosome 16p11-p12 has been investigated as a positional and functional candidate for inflammatory bowel disease (IBD) susceptibility. Screening of the six exons of IGSF6 for single nucleotide polymorphisms (SNPs) detected four novel SNPs, and validated three of six SNPs listed in the international SNP database (dbSNP). The seven SNPs in IGSF6 formed five distinct linkage disequilibrium groups. There was no evidence for association of the common SNPs with disease in a large cohort of patients with IBD. The novel SNPs and the linkage disequilibrium map will be a useful resource for the analysis of IGSF6 in other immune disorders.

Diagnosis of trisomy 21 in preimplantation embryos by single-cell DNA fingerprinting

Many couples presenting for preimplantation genetic diagnosis (PGD) for a single gene disorder are of advanced reproductive age (>35 years) and have a greater chance of producing embryos with chromosomal aneuploidies. The most common chromosomal aneuploidy observed in newborns is trisomy 21, or Down's syndrome. Consequently, the availability of a highly reliable system that simultaneously detects the heritable gene disorder and trisomy 21 would be beneficial to couples at specific risk. A pentaplex chromosome 21 (Ch 21) single-cell DNA fingerprinting system was developed in a multiplex fluorescence polymerase chain reaction (FL-PCR) on single cells. High reliability and accuracy rates were observed, together with low allele dropout (ADO) and preferential amplification rates on diploid buccal cells, trisomy 21 buccal cells and blastomeres derived from Ch 21 aneuploid embryos. A combined multiplex FL-PCR format was optimized with the common cystic fibrosis delta F508 mutation and validated on single buccal cells from a carrier of the cystic fibrosis delta F508 mutation. This new test is a very powerful technique, which also allows confirmation of the embryo parentage and the identification of extraneous DNA contamination that could cause a misdiagnosis in PGD cases.

Absence of a genetic association between IL-1RN and IL-1B gene polymorphisms in ulcerative colitis and Crohn disease in multiple populations from northeast England

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract of unknown aetiology, phenotypically categorized into ulcerative colitis (UC) and Crohn disease (CD). Genetic factors are of considerable importance in both. The genetic relationship between IBD and the interleukin-1 receptor antagonist and interleukin-1beta genes (IL-1RN, and IL-1B, respectively) has been extensively studied. However, the quality and outcome of the genetic association studies, in particular the association with IL-1RN*2, have been variable and these associations remain controversial. The aim of the present study was to re-investigate these two candidate genes in a large series of IBD patients from a genetically homogeneous population with low levels of population admixture, and provide a definitive answer to this question.

METHODS

A total of 529 northern European Caucasoid patients with IBD (347 UC, 182 CD) and 289 racially and geographically matched healthy controls were studied. The IL-1RN and IL-1B genotypes, allele frequencies and most probable haplotypes were determined by standard PCR protocols.

RESULTS

There were no significant differences in the distributions of the IL-1RN and IL-1B genotypes, allele frequencies or haplotypes in either patient series compared to healthy controls or between clinical subsets. Genotype distribution and frequency data for allele 2 (IL-1RN*2) in particular showed no significant differences across all patient groups for all three series.

CONCLUSION

The findings of this study lead us to reject the IL-1RN*2 association with IBD.

The RPM1 plant disease resistance gene facilitates a rapid and sustained increase in cytosolic calcium that is necessary for the oxidative burst and hypersensitive cell death

Early events occurring during the hypersensitive resistance response (HR) were examined using the avrRpm1/RPM1 gene-for-gene interaction in Arabidopsis challenged by Pseudomonas syringae pv. tomato. Increases in cytosolic Ca2+ were measured in whole leaves using aequorin-mediated bioluminescence. During the HR a sustained increase in Ca2+ was observed which was dependent on the presence of both a functional RPM1 gene product and delivery of the cognate avirulence gene product AvrRpm1. The sequence-unrelated avirulence gene avrB, which also interacts with RPM1, generated a significantly later but similarly prolonged increase in cytosolic Ca2+. Accumulation of H2O2 at reaction sites, as revealed by electron microscopy, occurred within the same time frame as the changes in cytosolic Ca2+. The NADPH oxidase inhibitor diphenylene iodonium chloride did not affect the calcium signature, but did block H2O2 accumulation and the HR. By contrast, the calcium-channel blocker LaCl3 suppressed the increase in cytosolic Ca2+ as well as H2O2 accumulation and the HR, placing calcium elevation upstream of the oxidative burst.

Infrared and Raman imaging of biological and biomimetic samples

Established methods for imaging of biological or biomimetic samples, such as fluorescence and optical microscopy, magnetic resonance imaging (MRI), X-ray tomography or positron emission tomography (PET) are currently complemented by infrared (both near-IR and mid-IR) as well as Raman spectroscopic imaging, whether it be on a microscopic or macroscopic scale. These vibrational spectroscopic techniques provide a wealth of information without a priori knowledge of either the spectral data or the composition of the sample. Infrared radiation does not harm the organism, no electric potential needs to be applied, and the measurements are not influenced by electromagnetic fields. In addition, no extrinsic labeling or staining, which may perturb the system under investigation, has to be added. The immense volume of information contained in spectroscopic images requires multivariate analysis methodologies in order to effectively mine the chemical and spatial information contained within the data as well as to analyze a time-series of images in order to reveal the origin of a chemical or biochemical process. The promise and limitations of this new analytical tool are surveyed in this review.

Early events in host-pathogen interactions

Research focused on early events in host-pathogen interactions has provided new insights into fundamental aspects of microbial pathogenicity and plant responses. Considerable progress has been made in understanding regulation of the delivery of pathogenicity determinants from bacteria into plant cells, signal cascades involved in fungal pathogenicity, the co-ordinating role of the plant cytoskeleton in plant defence and calcium flux as a primary signalling function during the hypersensitive reaction.

Using population-based data to enhance clinical practice guideline development

OBJECTIVES

Working with the College of Physicians and Surgeons of Manitoba, and using tonsillectomies as a basis of inquiry, MCHPE examined surgical rates and patterns of practice. This project had three major aims: to review whether current patterns of delivery provide optimal care; to enhance the development of clinical guidelines; and to inform and influence physician practice.

RESEARCH DESIGN

Both a population-based method of inquiry (which permits comparisons across population groups) and a provider-based approach (which offers insights into differences in the nature of care offered by different types of hospitals and physicians) were used.

MEASURES

Synergies between these two approaches offered useful insight into aspects of quality and efficiency of care.

RESULTS

Consistent with other jurisdictions, there was a high degree of variability across regions. However, there were also a number of surprising findings, including high rates of surgery in females, in older children, and among residents of rural areas. Data analysis raised a number of quality-of-care issues related to small caseload volumes, performance of procedures in very young children, and patterns of postoperative care in rural hospitals. The analyses provided impetus for addressing these issues in the guideline and suggested that the target audience for intervention should be rural physicians rather than urban specialists.

CONCLUSIONS

This project demonstrated that data analysis can provide a powerful adjunct to the development and implementation of clinical practice guidelines.

Expression of avrPphB, an avirulence gene from Pseudomonas syringae pv. phaseolicola, and the delivery of signals causing the hypersensitive reaction in bean

Protein production encoded by the avirulence gene avrPphB from Pseudomonas syringae pv. phaseolicola was examined. Incorporation of [35S]-labeled methionine into the AvrPphB protein indicated processing of the full-length peptide in Escherichia coli to give a major 28-kDa product. The 28-kDa native peptide was isolated from E. coli following over-expression of avrPphB and found not to elicit the hypersensitive response (HR) after infiltration into bean leaves. Antiserum raised to the 28-kDa peptide allowed expression of avrPphB and processing of AvrPphB protein to be examined in P. syringae pv. phaseolicola; immunoreactive peptides of both 35 and 28-kDa were detected in races 3 and 4 (which contain avrPphB) only after induction in minimal medium + 10 mM sucrose. Antiserum raised to a synthetic peptide, derived from the sequence of the 62 amino acids found to be cleaved from the full-length AvrPphB protein, revealed the accumulation of peptides corresponding to the smaller cleavage products, in both E. coli and P. syringae pv. phaseolicola. Biochemical localization experiments showed that all AvrPphB peptides were cytoplasmic in P. syringae pv. phaseolicola. No AvrPphB peptides were produced in a hrpL mutant unless expression of the gene was directed by a strong vector promoter; induction kinetics similar to wild type were observed in a hrpY- strain, although it also failed to cause a confluent HR. Growth of P. syringae pv. phaseolicola under inducing conditions removed the requirement for rifampicin-sensitive mRNA synthesis by bacteria to allow HR development (the induction time) in bean and lettuce leaves. Constitutive expression of hrpL reduced but did not remove the induction time. Expression of the hrp gene cluster of P. syringae pv. phaseolicola from plasmid pPPY430 in E. coli enabled phenotypic expression of avrPphE (also carried by pPPY430) and avrPphB (if over-expressed from pPPY3031). Despite constitutive expression of the hrp and avr genes in E. coli, a protein synthesis dependent induction time was still required for development of the HR in bean genotypes with matching resistance genes. The significance of processing for the function of AvrPphB peptides and the delivery of elicitors of the HR are discussed.

TNF2, a polymorphism of the tumour necrosis-alpha gene promoter, is a component of the celiac disease major histocompatibility complex haplotype

Celiac disease (CD) is an immune disease triggered by the cereal antigen gliadin, resulting in villous atrophy in the small intestine. Susceptibility to the development of CD is strongly influenced by genes in the major histocompatibility complex, in particular alleles of the DQ genes in the class II region. However recent evidence has suggested that the major histocompatibility complex (MHC) class III region may be linked to celiac disease independently of the class II region. Among the genes located in this area is TNF-alpha, which encodes the cytokine tumor necrosis factor-alpha which has a broad range of pro-inflammatory, immunomodulatory and catabolic activities. Therefore, aberrant expression of TNF-alpha could be important in the pathogenesis of MHC-associated immune disorders. A TNF-alpha variant with a polymorphism in its promoter region has been described and designated TNF2. TNF2 has been associated with a variety of MHC-linked diseases, including systemic lupus erythematosus, dermatitis herpetiformis and insulin-dependent diabetes mellitus (IDDM), as well as parasitic infections. TNF2 has previously been shown to be associated with the MHC haplotype HLA A1-B8-DR3-DQ2, which confers susceptibility to CD. We have analyzed the distribution of TNF2 alleles in a group of celiac patients (n = 52) compared to controls (n = 52) in an effort to evaluate its role, if any, in susceptibility to the condition. TNF2 has a frequency of 0.5000 (SE +/- 0.0490) in CD, compared to 0.1635 (+/- 0.0362) in a control sample (p < 10(-6)). Of 52 patients, 44 carried one or more TNF2 alleles. Analysis indicates that the distribution of TNF2 is best explained by assuming 100% allelic association between it and HLA-DQB1*0201 (frequency = 0.7791 +/- 0.0447). However, the number of TNF2 heterozygotes significantly exceeds expectations and measurements of linkage disequilibrium confirm that allelic associations spanning the DQ and TNF regions are strongly maintained in CD. Taken together, these results indicate that TNF2 may have a role in the pathogenesis of CD; however, since it is not an independent association, the possibility that TNF2 constitutes a passive component of the CD haplotype cannot be excluded.

Biochemical and mutational analysis of the histidine residues of staphylococcal enterotoxin A

The goal of this study was to examine the role of histidine residues in the biological activities of staphylococcal enterotoxin A (SEA). Carboxymethylated SEA was unable to stimulate murine T-cell proliferation but was resistant to monkey stomach lavage fluid degradation, suggesting that native conformation was intact. Site-directed mutagenesis of the histidine residues of SEA was subsequently performed. SEA-H44A (SEA with histidine 44 replaced with alanine), SEA-H44D, SEA-H50A, SEA-H50D, SEA-H114A, SEA-H114D, SEA-H187A, and SEA-H187D retained superantigen and emetic activities, whereas SEA-H225A and SEA-H225D were defective in the ability to stimulate T-cell proliferation. These mutants were unable to compete with SEA for binding to Raji cells, suggesting that the defect in SEA-H225A and SEA-H225D is due to impaired major histocompatibility complex class II binding. SEA-H225D provoked an emetic response in monkeys only if fed at high doses, while SEA-H225A did not provoke an emetic response at low or high doses. In comparison, SEA-H61A and SEA-H61D were defective in emetic activity but not in the ability to stimulate murine T-cell proliferation. Overall, these studies show that the carboxy-terminal histidine at residue position 225 of SEA is important for both the superantigen and emetic activities of this enterotoxin. Histidine 61 appears to be important for emetic activity but not for superantigen activity, consistent with the hypothesis that the two activities are separable in staphylococcal enterotoxins.

Neural network classification of infrared spectra of control and Alzheimer's diseased tissue

Artificial neural network classification methods were applied to infrared spectra of histopathologically confirmed Alzheimer's diseased and control brain tissue. Principal component analysis was used as a preprocessing technique for some of these artificial neural networks while others were trained using the original spectra. The leave-one-out method was used for cross-validation and linear discriminant analysis was used as a performance benchmark. In the cases where principal components were used, the artificial neural networks consistently outperformed their linear discriminant counterparts; 100% versus 98% correct classifications, respectively, for the two class problem, and 90% versus 81% for a more complex five class problem. Using the original spectra, only one of the three selected artificial neural network architectures (a variation of the back-propagation algorithm using fuzzy encoding) produced results comparable to the best corresponding principal component cases: 98% and 85% correct classifications for the two and five class problems, respectively.

Characterization of avrPphE, a gene for cultivar-specific avirulence from Pseudomonas syringae pv. phaseolicola which is physically linked to hrpY, a new hrp gene identified in the halo-blight bacterium

The avirulence gene matching the R2 gene for resistance to halo-blight disease in Phaseolus was cloned and sequenced from race 4 strain 1302A of Pseudomonas syringae pv. phaseolicola. The predicted 41-kDa AvrPphE protein is hydrophilic, has no features that indicate function, and no similarity to other protein sequences. The promoter region of avrPphE contains a "harp box" motif. The gene was expressed more strongly in minimal than in nutrient-rich media. Lower concentrations of the phytoalexin phaseollin accumulated in tissue undergoing the hypersensitive reaction (HR) determined by avrPphE than by avrPphB. Homologs of avrPphE were detected in strains representing eight races of P. s. pv. phaseolicola including those virulent on cultivars with the R2 resistance gene, and in P. s. pv. tabaci but not in P. cichorii or P. s. pvs. coronafaciens, glycinea, maculicola, pisi, or syringae. Disruption of avrPphE prevented induction of the HR but did not appear to affect basic pathogenicity. Transposon mutagenesis and DNA sequencing showed that avrPphE was linked to hrpY a hrp locus identified at the left end of the hrp gene cluster. Sequence analysis showed that the region linked to avrPphE was very similar to DNA containing hrp genes from P. s. pv. syringae including hrpJ, hrpL, and hrpK.

Quantitative assessment of four men using above-elbow prosthetic control

We studied the relationship between kinematically unconstrained activities of daily living (ADL) tasks and a kinematically constrained task in above-elbow (AE) amputee subjects using myoelectrically controlled prostheses. Four men, 24 to 49 years old, with unilateral AE amputation wore a prosthesis interfaced to a programmable controller to emulate two different elbow control schemes, conventional velocity and a new "natural" controller. Subjects were timed during three ADL tasks--cutting meat, donning socks, and rolling dough--with both controllers. The prosthesis emulator was then connected to a crank device with a handle, and the subjects turned the crank from bottom to top positions in a vertical plane using each controller. Synergistic shoulder-elbow joint coordination required for crank turning was quantified as the maximum slope of the change in elbow torque versus the change in crank-angle. Performance between the two controllers differed significantly for the crank test but not for ADL tasks. One subject did not complete all crank turning tests. Positive canonical correlation of 0.77 was found between time and crank domain measures. We conclude that biomechanical assessments should be integrated with time-based clinical tests to comprehensively evaluate performance of AE amputee subjects with a myoelectric device.

Functional homologs of the Arabidopsis RPM1 disease resistance gene in bean and pea

We showed that a bacterial avirulence (avr) gene function, avrPpiA1, from the pea pathogen Pseudomonas syringae pv pisi, is recognized by some, but not all, genotypes of Arabidopsis. Thus, an avr gene functionally defined on a crop species is also an avr gene on Arabidopsis. The activity of avrPpiA1 on a series of Arabidopsis genotypes is identical to that of the avrRpm1 gene from P.s. pv maculicola previously defined using Arabidopsis. The two avr genes are homologous and encode nearly identical predicted products. Moreover, this conserved avr function is also recognized by some bean and pea cultivars in what has been shown to be a gene-for-gene manner. We further demonstrated that the Arabidopsis disease resistance locus, RPM1, conditioning resistance to avrRpm1, also conditions resistance to bacterial strains carrying avrPpiA1. Therefore, bean, pea, and conceivably other crop species contain functional and potentially molecular homologs of RPM1.

Gene-for-gene interactions between Pseudomonas syringae pv. phaseolicola and Phaseolus

The gene for cultivar-specific avirulence to Phaseolus vulgaris cv. Tendergreen in races 3 and 4 of Pseudomonas syringae pv. phaseolicola was isolated and sequenced. Genomic clones from libraries of race 3 in pLAFR1 and race 4 in pLAFR3, which altered the phenotype of race 5 from virulent to avirulent in Tendergreen, were found to possess a common approximately 15-kb region of DNA that contained the determinant of avirulence. Subcloning and insertion mutagenesis with Tn1000 located an avirulence gene within a 1.4-kb BglII/HindIII DNA fragment in races 3 and 4. Comparison of the nucleotide sequences of regions of DNA that confer avirulence confirmed that both races have an identical gene for avirulence (designated avrPph3) comprising 801 base pairs (bp) and predicted to encode a cytoplasmic protein of 28,703 Da. A sequence, TGCAACCGAAT, 91% homologous to the motif found in promoter regions of avrB and avrD from P. s. pv. glycinea was located 89-99 bp upstream of the start of the open-reading frame 1. Hybridization experiments showed that avrPph3 was not plasmid-borne and was absent from isolates of P. s. pv. phaseolicola races 1, 2, 5, 6, 7, and 8, P. cichorii, P. s. pvs. coronafaciens, glycinea, maculicola, pisi, syringae, and tabaci. Cosegregation studies of crosses between cultivars resistant (Tendergreen) and susceptible (Canadian Wonder) to races 3 and 4 and transconjugants of race 5 confirmed that a gene-for-gene relationship controls specificity in the interaction between Tendergreen and races 3 and 4 of P. s. pv. phaseolicola.

Gene-for-gene interactions between Pseudomonas syringae pv. phaseolicola and Phaseolus

The gene for cultivar-specific avirulence to Phaseolus vulgaris cv. Tendergreen in races 3 and 4 of Pseudomonas syringae pv. phaseolicola was isolated and sequenced. Genomic clones from libraries of race 3 in pLAFR1 and race 4 in pLAFR3, which altered the phenotype of race 5 from virulent to avirulent in Tendergreen, were found to possess a common approximately 15-kb region of DNA that contained the determinant of avirulence. Subcloning and insertion mutagenesis with Tn1000 located an avirulence gene within a 1.4-kb BglII/HindIII DNA fragment in races 3 and 4. Comparison of the nucleotide sequences of regions of DNA that confer avirulence confirmed that both races have an identical gene for avirulence (designated avrPph3) comprising 801 base pairs (bp) and predicted to encode a cytoplasmic protein of 28,703 Da. A sequence, TGCAACCGAAT, 91% homologous to the motif found in promoter regions of avrB and avrD from P. s. pv. glycinea was located 89-99 bp upstream of the start of the open-reading frame 1. Hybridization experiments showed that avrPph3 was not plasmid-borne and was absent from isolates of P. s. pv. phaseolicola races 1, 2, 5, 6, 7, and 8, P. cichorii, P. s. pvs. coronafaciens, glycinea, maculicola, pisi, syringae, and tabaci. Cosegregation studies of crosses between cultivars resistant (Tendergreen) and susceptible (Canadian Wonder) to races 3 and 4 and transconjugants of race 5 confirmed that a gene-for-gene relationship controls specificity in the interaction between Tendergreen and races 3 and 4 of P. s. pv. phaseolicola.

Practical phase identification by convergent beam electron diffraction

The purpose of this article is to present a practical guide to the identification of phases in the analytical electron microscope with the aid of convergent beam electron diffraction. There is included a step-by-step approach to phase analysis, from the possible choices of the form of the specimen through how to explore reciprocal space in order to perform a full phase identification, either by symmetry analysis or by simple comparison of a pattern observed in the microscope with a previously recorded pattern (fingerprinting). There is a strong emphasis on practical hints and useful shortcuts.

Treatment with dexamethasone of androgen excess in adolescent patients

Fourteen hirsute girls, ages 12 to 22 years (mean +/- SD: 17.2 +/- 2.6 years), in whom 21-hydroxylase deficiency was excluded by a 1-hour intravenous alpha 1-24 corticotropin test, were evaluated by a 4-day dexamethasone test and then treated with a bedtime dose of dexamethasone (0.5 mg in 10 patients, 0.25 mg in four) for 0.6 to 3.4 years (1.3 +/- 0.8 years). Hirsutism decreased in four patients, did not change in nine, and increased in one. Of the 10 patients with irregular menses, only three developed regular cycles while taking dexamethasone. During long-term dexamethasone therapy, serum levels of testosterone decreased from 102 +/- 22 to 72 +/- 27 ng/dL, free testosterone from 35 +/- 11 to 19 +/- 8 pg/mL, and dehydroepiandrosterone sulfate from 396 +/- 138 to 171 +/- 101 micrograms/dL. Although free testosterone decreased to less than 15 pg/mL in eight of 14 patients with the suppression test, only four patients had free testosterone levels less than 15 pg/mL during therapy. Two of the 14 patients have had no recurrence of hirsutism or increase in serum androgens after 28 and 29 months, respectively, after dexamethasone therapy was discontinued. Oral contraceptives were given to nine patients inadequately responsive to bedtime dexamethasone therapy. The mean percent decrease of testosterone and free testosterone levels during oral contraceptive therapy was significantly greater than during long-term treatment with dexamethasone, and hirsutism lessened in all. We conclude that a single bedtime dose of dexamethasone is satisfactory only in patients who maintain serum free testosterone values less than 15 pg/mL without side effects. For other patients, either another glucocorticoid or, in most cases, ovulation suppression should be prescribed for adolescents with progressive hirsutism and elevated androgen levels.

The relationships of calculated percent body fat, sports participation, age, and place of residence on menstrual patterns in healthy adolescent girls at an independent new England high school

A prospective study was undertaken to determine normal menstrual patterns in healthy girls in an independent high school and assess the effects of exercise (type and hours per day), age (chronologic and gynecologic), calculated estimate of body fat, and place of residence (boarding and day students) on menstrual function. Three hundred twenty-seven girls (means age 15.5 +/- 1.1 years) answered a questionnaire on menstrual history; 306 (93.6%) were postmenarchal and 21 (6.4%) premenarchal. Calculated estimate of percent body fat was significantly lower in premenarchal than postmenarchal girls (22.4% versus 27.3% p less than 0.0001). Ninety-three percent of adolescents reported flow lasting 4-7 days; 59.7% dysmenorrhea; and 63% premenstrual symptoms. There was no correlation between estimated body fat or hours per day of exercise and the regularity of menses, duration of flow, or dysmenorrhea. With the exception of gymnastics and dancing, sports participation had little or no impact on menstrual patterns. Follow up questionnaires and menstrual calendars were obtained from 87 girls eight to fifteen months after the initial questionnaires. All girls whose cycles had changed from regular to irregular were boarding students, confirming previous anecdotal reports that separation from home may be a significant stress for adolescents.