Quantifying the effectiveness of ultraviolet-C light at inactivating airborne Mycobacterium abscessus

BACKGROUND

Mycobacterium abscessus (MABS) group are environmental organisms that can cause infection in people with cystic fibrosis (CF) and other suppurative lung diseases. There is potential for person-to-person airborne transmission of MABS among people with CF attending the same care centre. Ultraviolet light (band C, UV-C) is used for Mycobacterium tuberculosis control indoors; however, no studies have assessed UV-C for airborne MABS.

AIM

To determine whether a range of UV-C doses increased the inactivation of airborne MABS, compared with no-UVC conditions.

METHODS

MABS was generated by a vibrating mesh nebulizer located within a 400 L rotating drum sampler, and then exposed to an array of 265 nm UV-C light-emitting diodes (LED). A six-stage Andersen Cascade Impactor was used to collect aerosols. Standard microbiological protocols were used for enumerating MABS, and these quantified the effectiveness of UV-C doses (in triplicate). UV-C effectiveness was estimated using the difference between inactivation with and without UV-C.

FINDINGS

Sixteen tests were performed, with UV-C doses ranging from 276 to 1104 μW s/cm². Mean (±SD) UV-C effectiveness ranged from 47.1% (±13.4) to 83.6% (±3.3). UV-C led to significantly greater inactivation of MABS (all P-values ≤0.045) than natural decay at all doses assessed. Using an indoor model of the hospital environment, it was estimated that UV-C doses in the range studied here could be safely delivered in clinical settings where patients and staff are present.

CONCLUSION

This study provides empirical in-vitro evidence that nebulized MABS are susceptible to UV-C inactivation.

Role of Nose to Pelvis Imaging in the Evaluation of Foreign Body Ingestion: A Case of Magnet Ingestion in a 2-Year-Old

Foreign body ingestion (FBI) of small-rare-earth-magnets (SREM) sets are associated with high morbidity and mortality, as these tend to cause significant mucosal injury. Current clinical guidelines for the evaluation of FBI do not include imaging of the nose and neck. A 2-year-old patient presented with known SREM ingestion, with location confirmed in the right lower quadrant on imaging at the time of initial evaluation. Subsequent imaging involving the neck revealed additional magnets lodged in the patient's hypopharynx, which were missed on initial evaluation. This case highlights the importance of considering advanced imaging of the nose and neck to uncover extraintestinal foreign bodies.

Investigating surface binding effects: antibacterial efficacy of bound 8-hydroxyquinoline against Staphylococcus aureus and Escherichia coli

AIMS

To investigate the binding of the antimicrobial compound 8-hydroxyquinoline (8HQ) to a material interface and to determine whether immobilization affects the antibacterial efficacy.

METHODS AND RESULTS

The 8HQ derivative 5-carboxy-8-hydroxyquinoline (5C8HQ) was attached to silica beads through amide bond coupling at the carboxyl moiety of 5C8HQ. Attachment of 5C8HQ was confirmed using a combination of mass spectrometry, thermogravimetric analysis, colorimetric testing and Soxhlet extraction. Computational modelling results indicated that this substitution did not compromise the active sites on the molecule, whereas other positions on the ring system could potentially inhibit antimicrobial activity. The antibacterial effect of 8HQ and the 5C8HQ-modified silica complex against Escherichia coli 15597 (ATCC^® 25922) and Staphylococcus aureus (ATCC 25923) was evaluated.

CONCLUSIONS

The test results show that the immobilized 8HQ continues to exhibit antibacterial activity, however, quantifying the efficacy compared to free 8HQ bears further investigation. The expected antibacterial mechanism requires that the metal chelation site of 8HQ be retained and available after attachment to a surface. The retention of antibacterial activity after surface bonding represents a novel mechanism of action not previously reported.

SIGNIFICANCE AND IMPACT OF THE STUDY

Recent changes in regulations due to environmental concerns prompted many companies and organizations to explore antimicrobial treatments that are chemically bound to the product. Chemically bonding biocidal compounds to a surface limits environmental release; however, molecular mechanisms that drive antibacterial activity when compounds are immobilized are limited. The results reported here demonstrate that the 8HQ reactive site retains antibacterial efficacy even after covalent attachment to a surface. This approach supersedes other antimicrobial treatments where the active component is gradually released from the material surface in order to elicit antimicrobial effects. This specific antibacterial activity of bound 8HQ represents a novel mechanism of action not previously reported, and a potential conduit to a new class of bound antimicrobial materials.

Thermionic Cooling of the Target Plasma to a Sub-eV Temperature

Contemporary models of bounded plasmas assume that the target plasma electron temperature far exceeds the temperature of the cold electrons emitted from the target, T_{emit}. We show that when the sheath facing a collisional plasma becomes inverted, the target plasma electron temperature has to equal T_{emit} even if the upstream plasma is hotter by orders of magnitude. This extreme cooling effect can alter the plasma properties and the heat transmission to thermionically emitting surfaces in many applications. It also opens a possibility of using thermionic divertor plates to induce detachment in tokamaks.

Sources and dynamics of fluorescent particles in hospitals

Fluorescent particles can be markers of bioaerosols and are therefore relevant to nosocomial infections. To date, little research has focused on fluorescent particles in occupied indoor environments, particularly hospitals. In this study, we aimed to determine the spatial and temporal variation of fluorescent particles in two large hospitals in Brisbane, Australia (one for adults and one for children). We used an Ultraviolet Aerodynamic Particle Sizer (UVAPS) to identify fluorescent particle sources, as well as their contribution to total particle concentrations. We found that the average concentrations of both fluorescent and non-fluorescent particles were higher in the adults' hospital (0.06×10⁶ and 1.20×10⁶  particles/m³ , respectively) than in the children's hospital (0.03×10⁶ and 0.33×10⁶  particles/m³ , respectively) (P<.01). However, the proportion of fluorescent particles was higher in the children's hospital. Based on the concentration results and using activity diaries, we were able to identify sources of particle production within the two hospitals. We demonstrated that particles can be easily generated by a variety of everyday activities, which are potential sources of exposure to pathogens. Future studies to further investigate their role in nosocomial infection are warranted.

Environmental contamination and hospital-acquired infection: factors that are easily overlooked

There is an ongoing debate about the reasons for and factors contributing to healthcare-associated infection (HAI). Different solutions have been proposed over time to control the spread of HAI, with more focus on hand hygiene than on other aspects such as preventing the aerial dissemination of bacteria. Yet, it emerges that there is a need for a more pluralistic approach to infection control; one that reflects the complexity of the systems associated with HAI and involves multidisciplinary teams including hospital doctors, infection control nurses, microbiologists, architects, and engineers with expertise in building design and facilities management. This study reviews the knowledge base on the role that environmental contamination plays in the transmission of HAI, with the aim of raising awareness regarding infection control issues that are frequently overlooked. From the discussion presented in the study, it is clear that many unknowns persist regarding aerial dissemination of bacteria, and its control via cleaning and disinfection of the clinical environment. There is a paucity of good-quality epidemiological data, making it difficult for healthcare authorities to develop evidence-based policies. Consequently, there is a strong need for carefully designed studies to determine the impact of environmental contamination on the spread of HAI.

Pre-clinical and clinical walking kinematics in female breeding pigs with lameness: A nested case-control cohort study

Gait profiles were investigated in a cohort of female pigs experiencing a lameness period prevalence of 29% over 17 months. Gait alterations before and during visually diagnosed lameness were evaluated to identify the best quantitative clinical lameness indicators and early predictors for lameness. Pre-breeding gilts (n= 84) were recruited to the study over a period of 6 months, underwent motion capture every 5 weeks and, depending on their age at entry to the study, were followed for up to three successive gestations. Animals were subject to motion capture in each parity at 8 weeks of gestation and on the day of weaning (28 days postpartum). During kinematic motion capture, the pigs walked on the same concrete walkway and an array of infra-red cameras was used to collect three dimensional coordinate data of reflective skin markers attached to the head, trunk and limb anatomical landmarks. Of 24 pigs diagnosed with lameness, 19 had preclinical gait records, whilst 18 had a motion capture while lame. Depending on availability, data from one or two preclinical motion capture 1-11 months prior to lameness and on the day of lameness were analysed. Lameness was best detected and evaluated using relative spatiotemporal gait parameters, especially vertical head displacement and asymmetric stride phase timing. Irregularity in the step-to-stride length ratio was elevated (deviation  ≥ 0.03) in young pigs which presented lameness in later life (odds ratio 7.2-10.8).

Intercalation of trichloroethene by sediment-associated clay minerals

The objective of this research was to examine the potential for intercalation of trichloroethene (TCE) by clay minerals associated with aquifer sediments. Sediment samples were collected from a field site in Tucson, AZ. Two widely used Montmorillonite specimen clays were employed as controls. X-ray diffraction, conducted with a controlled-environment chamber, was used to characterize smectite interlayer d-spacing for three treatments (bulk air-dry sample, sample mixed with synthetic groundwater, sample mixed with TCE-saturated synthetic groundwater). The results show that the d-spacing measured for the samples treated with TCE-saturated synthetic groundwater are larger (~26%) than those of the untreated samples for all field samples as well as the specimen clays. These results indicate that TCE was intercalated by the clay minerals, which may have contributed to the extensive elution tailing observed in prior miscible-displacement experiments conducted with this sediment.

Nonideal transport of contaminants in heterogeneous porous media: 10. Impact of co-solutes on sorption by porous media with low organic-carbon contents

The impact of co-solutes on sorption of tetrachloroethene (PCE) by two porous media with low organic-carbon contents was examined by conducting batch experiments. The two media (Borden and Eustis) have similar physical properties, but significantly different organic-carbon (OC) contents. Sorption of PCE was nonlinear for both media, and well-described by the Freundlich equation. For the Borden aquifer material (OC=0.03%), the isotherms measured with a suite of co-solutes present (1,2-dichlorobenzene, bromoform, carbon tetrachloride, and hexachloroethane) were identical to the isotherms measured for PCE alone. These results indicate that there was no measurable impact of the co-solutes on PCE sorption for this system. In contrast to the Borden results, there was a measurable reduction in sorption of PCE by the Eustis soil (OC=0.38%) in the presence of the co-solutes. The organic-carbon fractions of both media contain hard-carbon components, which have been associated with the manifestation of nonideal sorption phenomena. The disparity in results observed for the two media may relate to relative differences in the magnitude and geochemical nature of these hard-carbon components.

Alteration of scapula lateral rotation for subjects with the reversed anatomy shoulder replacement and its influence on glenohumeral joint contact force

It has previously been reported that motion of the scapula varies for subjects with shoulder joint pathologies and is different from that of normal subjects. In this study, an electromagnetic tracking device was used to measure the three-dimensional scapula motion of nine patients with Bayley-Walker (B-W) reverse anatomy joint replacements. The data were then compared to scapula kinematics of 12 normal subjects with no known shoulder pathology. The scapula kinematics for each subject was determined and a regression analysis to find the mean scapula lateral rotation (SLR) for B-W and normal subjects was performed. The regression model which showed the highest change compared to normal was identified and was used in the biomechanical shoulder model to predict the glenohumeral joint contact force. A high variability of the scapula kinematics was observed, with some subjects having a maximum SLR smaller than that of the normal subjects and some similar to the normal subjects. It was found that scapula may move in such a way to keep the deltoid length at its optimum. The change in the scapula kinematics affected the predicted joint force and its point of application. Hence, knowledge of scapular kinematics is essential for realistic modelling of implanted shoulders.

Reverse anatomy shoulder replacement: comparison of two designs

The aim of this study was to use a biomechanical model of the shoulder to examine the characteristics of two concepts of reverse anatomy implant; those that preserve the natural glenohumeral centre such as the Bayley-Walker (B-W) replacement and those medializing it such as Delta. A biomechanical model of the shoulder was used to evaluate the biomechanical characteristics of these prostheses. The moment arms of the shoulder muscles were predicted for the implanted models over a wide workspace and were compared to those of natural anatomy. The deltoid muscle moment arms through almost all of the range of motion in the Delta model were greatest. As a result the shoulder joint contact force was decreased for this implant. Furthermore, although the B-W model predicted similar moment arms to natural anatomy, the contact force decreased owing to change in the joint constraints. Finally, it was concluded that the reverse anatomy can compensate for loss of rotator cuff muscles in terms of joint stability, yet the shoulder function depends on the individual's musculature.

Absence of truncating BRIP1 mutations in chromosome 17q-linked hereditary prostate cancer families

Background:

In a genome-wide scan (GWS) of 175 multiplex prostate cancer (PCa) families from the University of Michigan Prostate Cancer Genetics Project (PCGP), linkage was observed to markers on chromosome 17q21–24, a region that includes two breast cancer susceptibility genes, BRCA1 and BRIP1. BRIP1 is a Fanconi anaemia gene (FANCJ) that interacts with the BRCT domain of BRCA1 and has a role in DNA damage repair. Protein truncating mutations in BRIP1 have been identified in hereditary breast and ovarian cancer families, and a recent report suggested that a recurrent truncating mutation (R798X) may have a role in PCa susceptibility.

Methods:

We examined the role of BRIP1 mutations in hereditary PCa through sequence analysis of 94 individuals from PCGP families showing linkage to 17q.

Results:

A total of 24 single-nucleotide polymorphisms, including 7 missense variants but no protein truncating mutations, were observed.

Conclusion:

The data presented here suggest that BRIP1 truncating mutations are uncommon in PCa cases and do not account for the linkage to chromosome 17q observed in our GWS. Additional investigation is needed to determine the significance, if any, of the observed BRIP1 missense variants in hereditary PCa.

Application of bag sampling technique for particle size distribution measurements

Bag sampling techniques can be used to temporarily store the aerosol and therefore provide sufficient time to utilize sensitive but slow instrumental techniques for recording detailed particle size distributions. Laboratory based assessment of the method was conducted to examine size dependant deposition loss coefficients for aerosols held in Velostat bags conforming to a horizontal cylindrical geometry. Deposition losses of NaCl particles in the range of 10 nm to 160 nm were analysed in relation to the bag size, storage time, and sampling flow rate. Results of this study suggest that the bag sampling method is most useful for moderately short sampling periods of about 5 minutes.

Mass removal and low-concentration tailing of trichloroethene in freshly-amended, synthetically-aged, and field-contaminated aquifer material

This study investigates the effect of contaminant aging on the sorption/desorption and transport of trichloroethene in a low organic-carbon content aquifer material, comparing mass removal and long-term, low-concentration elution tailing for field-contaminated, synthetically-aged (contact times of approximately four years), and freshly-amended aquifer material. Elution of trichloroethene exhibited extensive low-concentration tailing, despite minimal retention of trichloroethene by the aquifer material. The observed nonideal transport behavior of trichloroethene is attributed primarily to rate-limited sorption/desorption, with a smaller contribution from nonlinear sorption. It is hypothesized that interaction with physically condensed carbonaceous material, comprising 61% of the aquifer material's organic-carbon content, mediates the retention behavior of trichloroethene. The elution behavior of trichloroethene for the field-contaminated and aged treatments was essentially identical to that observed for the fresh treatments. In addition, the results of three independent mass-balance analyses, total mass eluted, solvent-extraction analysis of residual sorbed mass, and aqueous-phase concentration rebounds following stop-flow experiments, showed equivalent recoveries for the aged and fresh treatments. These results indicate that long-term contaminant aging did not significantly influence the retention and transport of trichloroethene in this low organic-carbon aquifer material.

A framework for the definition of standardized protocols for measuring upper-extremity kinematics

BACKGROUND

Increasing interest in upper extremity biomechanics has led to closer investigations of both segment movements and detailed joint motion. Unfortunately, conceptual and practical differences in the motion analysis protocols used up to date reduce compatibility for post data and cross validation analysis and so weaken the body of knowledge. This difficulty highlights a need for standardised protocols, each addressing a set of questions of comparable content. The aim of this work is therefore to open a discussion and propose a flexible framework to support: (1) the definition of standardised protocols, (2) a standardised description of these protocols, and (3) the formulation of general recommendations.

METHODS

Proposal of a framework for the definition of standardized protocols.

FINDINGS

The framework is composed by two nested flowcharts. The first defines what a motion analysis protocol is by pointing out its role in a motion analysis study. The second flowchart describes the steps to build a protocol, which requires decisions on the joints or segments to be investigated and the description of their mechanical equivalent model, the definition of the anatomical or functional coordinate frames, the choice of marker or sensor configuration and the validity of their use, the definition of the activities to be measured and the refinements that can be applied to the final measurements. Finally, general recommendations are proposed for each of the steps based on the current literature, and open issues are highlighted for future investigation and standardisation.

INTERPRETATION

Standardisation of motion analysis protocols is urgent. The proposed framework can guide this process through the rationalisation of the approach.

The biomechanics of reverse anatomy shoulder replacement--a modelling study

BACKGROUND

Reverse anatomy shoulder prostheses, in which a partial sphere is attached to the scapula and a socket to the humerus, have become popular for the treatment of arthritic shoulders with severe rotator cuff arthropathy. While they have been in relatively common use, their biomechanical aspects have not been fully investigated.

METHODS

This study uses an adaptation of a 3D biomechanical shoulder model to describe the DELTA reverse prosthetic shoulder geometry and to investigate its properties. The muscle configuration was modified to represent the pathology and joint contact forces were computed for standardised activities.The model also uses a contact detect algorithm to record the impingement of the prosthesis with the scapula.

FINDINGS

Results showed that the reverse design increases the deltoid function compensating for the dysfunctional rotator cuff muscles by providing sufficient moment arm (increased by 42%) to elevate the arm. It also restores joint stability by reversing the envelope of the joint contact forces and reacting to the increased shear forces. Despite these advantages, the model also confirms impingement and predicts bone notches from the contact of the prosthesis with the scapula border. Results indicate that optimised fixation and design alterations can reduce the problem but is difficult to eliminate it without compromising the joint stability.

INTERPRETATION

The study provides a deep understanding of the function of the reverse designs highlighting their advantages in irreparable rotator cuff arthropathy but also the associated problems that compromise their use. Despite the limitations results indicate that reverse designs can be optimised to provide maximum functionality.

Characterization of expiration air jets and droplet size distributions immediately at the mouth opening

Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 μm and it was 16.0 μm for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm^-3 per cough and 0.004-0.223 cm^-3 for speaking.

Characterization of expiration air jets and droplet size distributions immediately at the mouth opening

Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 μm and it was 16.0 μm for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm^-3 per cough and 0.004-0.223 cm^-3 for speaking.

Particle and gaseous emissions from commercial aircraft at each stage of the landing and takeoff cycle

A novel technique was used to measure emission factors for commonly used commercial aircraft including a range of Boeing and Airbus airframes under real world conditions. Engine exhaust emission factors for particles in terms of particle number and mass (PM2.5), along with those for CO2 and NOx, were measured for over 280 individual aircraft during the various modes of landing/takeoff (LTO) cycle. Results from this study show that particle number, and NOx emission factors are dependent on aircraft engine thrust level. Minimum and maximum emissions factors for particle number, PM2.5, and NOx emissions were found to be in the range of 4.16 x 10(15)-5.42 x 10(16) kg(-1), 0.03-0.72 g.kg(-1), and 3.25-37.94 g.kg(-1), respectively, for all measured airframes and LTO cycle modes. Number size distributions of emitted particles for the naturally diluted aircraft plumes in each mode of LTO cycle showed that particles were predominantly in the range of 4-100 nm in diameter in all cases. In general, size distributions exhibit similar modality during all phases of the LTO cycle. A very distinct nucleation mode was observed in all particle size distributions, except for taxiing and landing of A320 aircraft. Accumulation modes were also observed in all particle size distributions. Analysis of aircraft engine emissions during LTO cycle showed that aircraft thrust level is considerably higher during taxiing than idling suggesting that International Civil Aviation Organization (ICAO) standards need to be modified as the thrust levels for taxi and idle are considered to be the same (7% of total thrust) (Environmental Protection, Annex 16, Vol. II, Aircraft Engine Emissions, 2nd ed.; ICAO--International Civil Aviation Organization: Montreal, 1993).

Algorithms for exact multi-object muscle wrapping and application to the deltoid muscle wrapping around the humerus

Lines of action of muscle forces imply the function and performance of muscles acting around joints. It is not always possible to determine muscle force lines of action in vivo, and so computational techniques are often used to predict them. It is common to model a muscle as a taut elastic string that follows the shortest geodesic path between attachments over the wrapping geometry. A number of studies have been concerned with wrapping paths over single wrapping objects, and those that have considered more objects have applied the single-object solutions with iterative approaches to the search for a solution. This study presents a more efficient methodology for finding the exact solutions to a certain class of wrapping problems in which the path is constrained by multiple surfaces. It also introduces a more general wrapping technique based on the idea of energy minimization, which has been successfully validated against the exact solution. These methods are applied to the case of an element of the deltoid wrapping around the humerus modelled as a composite sphere—cylinder. Comparison of results with those obtained from approximated single-object solutions demonstrates the need to include correct multi-object wrapping algorithms in biomechanical models.

A comparative investigation of ultrafine particle number and mass emissions from a fleet of on-road diesel and CNG buses

Particle number, particle mass, and CO2 concentrations were measured on the curb of a busy urban busway used entirely by a mix of diesel and CNG operated buses. With the passage of each bus, the ratio of particle number concentration and particle mass concentration to CO2 concentration in the diluted exhaust plume were used as measures of the particle number and mass emission factors, respectively. With all buses accelerating pastthe monitoring point, the results showed that the median particle mass emission from CNG buses was less than 9% of that from diesel buses. However, the median particle number emission from CNG buses was 6 times higher than the diesel buses, and the particles from the CNG buses were mainly in the nanoparticle size range. Using a thermodenuder to remove the volatile material from the sampled emissions showed that the majority of particles from the CNG buses, but not from the diesel buses, were volatile. Approximately, 82% of the particles from the CNG buses and 38% from the diesel buses were removed by heating the emissions to 300 degrees C.

A plume capture technique for the remote characterization of aircraft engine emissions

A technique for capturing and analyzing plumes from unmodified aircraft or other combustion sources under real world conditions is described and applied to the task of characterizing plumes from commercial aircraft during the taxiing phase of the Landing/Take-Off (LTO) cycle. The method utilizes a Plume Capture and Analysis System (PCAS) mounted in a four-wheel drive vehicle which is positioned in the airfield 60 to 180 m downwind of aircraft operations. The approach offers low test turnaround times with the ability to complete careful measurements of particle and gaseous emission factors and sequentially scanned particle size distributions without distortion due to plume concentration fluctuations. These measurements can be performed for individual aircraft movements at five minute intervals. A Plume Capture Device (PCD) collected samples of the naturally diluted plume in a 200 L conductive membrane conforming to a defined shape. Samples from over 60 aircraft movements were collected and analyzed in situ for particulate and gaseous concentrations and for particle size distribution using a Scanning Particle Mobility Sizer (SMPS). Emission factors are derived for particle number, NO(x), and PM2.5 for a widely used commercial aircraft type, Boeing 737 airframes with predominantly CFM56 class engines, during taxiing. The practical advantages of the PCAS include the capacity to perform well targeted and controlled emission factor and size distribution measurements using instrumentation with varying response times within an airport facility, in close proximity to aircraft during their normal operations.

Surface immunoglobulin characteristics of B-lymphocyte developmental states and B-lymphocyte colony-forming cells

B-lymphocyte colony-forming cells and various B-lymphocyte developmental states were examined for expression of surface immunoglobulin. B-lymphocyte colony-forming-cells appeared to possess a significantly greater amount of surface immunoglobulin than did newborn 'virgin' B lymphocytes. In terms of surface immunoglobulin content and physical property characteristics (established previously) B-lymphocyte colony-forming cells resembled a more mature B-lymphocyte subset. This subset, as characterized in previous studies, consists of mature virgin B cells that develop from the newborn virgin B cells via a process of nonspecific antigen-induced differentiation. An alternative possibility that B-lymphocyte colony-forming cells are memory B lymphocytes has not been eliminated by this study.

Varicella-zoster virus-specific immune responses in elderly recipients of a herpes zoster vaccine

BACKGROUND

A double-blind, placebo-controlled trial that involved 38,546 subjects > or =60 years old demonstrated efficacy of a high-potency live-attenuated Oka/Merck varicella-zoster virus (VZV) vaccine. The trial included an immunology substudy to determine the relationship of VZV-specific immune responses to vaccination and clinical outcome.

METHODS

The immunology substudy enrolled 1395 subjects at 2 sites where blood samples obtained prior to vaccination, at 6 weeks after vaccination, and at 1, 2, and 3 years thereafter were tested for VZV-specific cell-mediated immunity (VZV-CMI) by gamma-interferon ELISPOT and responder cell frequency assays and for VZV antibody by glycoprotein ELISA.

RESULTS

VZV-CMI and VZV antibodies were significantly increased in vaccine recipients at 6 weeks after vaccination. The vaccine-induced increases in VZV-CMI persisted during the 3 years of follow-up, although their magnitude decreased over time. The magnitude of these VZV-specific immune responses was greater in subjects 60-69 years old than in subjects > or =70 years old.

CONCLUSIONS

The zoster vaccine induced a significant increase in VZV-CMI and VZV antibody. The magnitude and duration of the boost in VZV-CMI in vaccine recipients and the relationship of this boost to age paralleled the clinical effects of the vaccine observed during the efficacy trial. These findings support the hypothesis that boosting VZV-CMI protects older adults against herpes zoster and postherpetic neuralgia.

Qualitative and quantitative descriptions of glenohumeral motion

Joint modelling plays an important role in qualitative and quantitative descriptions of both normal and abnormal joints, as well as predicting outcomes of alterations to joints in orthopaedic practice and research. Contemporary efforts in modelling have focussed upon the major articulations of the lower limb. Well-constrained arthrokinematics can form the basis of manageable kinetic and dynamic mathematical predictions. In order to contain computation of shoulder complex modelling, glenohumeral joint representations in both limited and complete shoulder girdle models have undergone a generic simplification. As such, glenohumeral joint models are often based upon kinematic descriptions of inadequate degrees of freedom (DOF) for clinical purposes and applications. Qualitative descriptions of glenohumeral motion range from the parody of a hinge joint to the complex realism of a spatial joint. In developing a model, a clear idea of intention is required in order to achieve a required application. Clinical applicability of a model requires both descriptive and predictive output potentials, and as such, a high level of validation is required. Without sufficient appreciation of the clinical intention of the arthrokinematic foundation to a model, error is all too easily introduced. Mathematical description of joint motion serves to quantify all relevant clinical parameters. Commonly, both the Euler angle and helical (screw) axis methods have been applied to the glenohumeral joint, although concordance between these methods and classical anatomical appreciation of joint motion is limited, resulting in miscommunication between clinician and engineer. Compounding these inconsistencies in motion quantification is gimbal lock and sequence dependency.

Glenohumeral motion: review of measurement techniques

Measurement of upper limb motion is problematic, not least because of the large range of path dependent description of motion of the joints, and the multiple non-cyclical unstandardised motion tasks measured. Furthermore, appreciation of shoulder motion specifically is obscured by overlying soft tissue. In order to satisfy the complexity of a clinically useful model of the movement of the joint, input data must be acquired from a set of pre-determined movements using a non-invasive technique with a high level of accuracy. Descriptive and predictive modeling of the glenohumeral joint requires input of high-fidelity data into a 6 degree of freedom representation, without which, the application of the tool is of limited clinical significance to the advancement of both operative and non-operative management of shoulder pathology. Electromagnetic, linkage and radiographic techniques have previously been used, however, an optimal solution is yet to be described.

A model for the prediction of the forces at the glenohumeral joint

The design, validation, and application of a three-dimensional musculoskeletal model of the upper limb is presented here, for the study of joint, muscle, and ligament forces during selected tasks of daily living. Much of the model was constructed using data gathered from real cadavers, including the extensive 'visible human' data set, together with information gathered from published post mortem studies on cadavers. Validation was carried out through comparison of model outcomes with available data in the literature. The model was then used to examine the glenohumeral joint loading during ten previously selected activities of daily living. The predicted glenohumeral joint contact forces during everyday activities were found to range from 23 to 75 per cent body weight. A linear regression method for estimating the joint load from externally measured kinetics was developed, giving a 95 per cent confidence interval in predicted joint forces of 8 per cent body weight. The model presented here, namely the Newcastle shoulder model, provides a basis for future studies into biomechanical problems relating to the understanding of musculoskeletal pathology and implant design and performance.

Novel method for on-road emission factor measurements using a plume capture trailer

The method outlined provides for emission factor measurements to be made for unmodified vehicles driving under real world conditions at minimal cost. The method consists of a plume capture trailer towed behind a test vehicle. The trailer collects a sample of the naturally diluted plume in a 200 L conductive bag and this is delivered immediately to a mobile laboratory for subsequent analysis of particulate and gaseous emissions. The method offers low test turnaround times with the potential to complete much larger numbers of emission factor measurements than have been possible using dynamometer testing. Samples can be collected at distances up to 3 m from the exhaust pipe allowing investigation of early dilution processes. Particle size distribution measurements, as well as particle number and mass emission factor measurements, based on naturally diluted plumes are presented. A dilution profile relating the plume dilution ratio to distance from the vehicle tail pipe for a diesel passenger vehicle is also presented. Such profiles are an essential input for new mechanistic roadway air quality models.

A systematic review of the Tardieu Scale for the measurement of spasticity

BACKGROUND

The Tardieu Scale has been suggested a more appropriate clinical measure of spasticity than the Ashworth or modified Ashworth Scales. It appears to adhere more closely to Lance's definition of spasticity as it involves assessment of resistance to passive movement at both slow and fast speeds.

OBJECTIVE

To review the available literature in which the Tardieu Scale has been used or discussed as a measure of spasticity, with a view to determining its validity and reliability.

STUDY DESIGN

A systematic review of all literature found related to the Tardieu Scale (keywords: Tardieu scale, spasticity) from Pubmed and Ovid databases, including medline, CINAHL, EMBASE, Journals at Ovid full text, EBM reviews and Cochrane database of systematic reviews. Hand searching was also used to track the source literature.

CONCLUSIONS

In theory, we can acknowledge that the Tardieu Scale does, in fact, adhere more closely to Lance's definition of spasticity. However, there is a dearth of literature investigating validity and reliability of the scale. Some studies have identified the Tardieu Scale to be more sensitive than other measures, to change following treatment with botulinum toxin. Further studies need to be undertaken to clarify the validity and reliability of the scale for a variety of muscle groups in adult neurological patients.

Particle number emissions and source signatures of an industrial facility

The work presented was conducted within the scope of a larger study investigating impacts of the Stuart Oil Shale project, a facility operating to the north of the industrial city of Gladstone, Australia. The aims of the investigations were threefold: (a) the identification of the plant signatures in terms of particle size distributions in the submicrometer range (13-830 nm) through stack measurements, (b) exploring the applicability of these signatures in tracing the source contributions at locations of interest, at a distance from the plant, and (c) assessing the contribution of the plant to the total particle number concentration at locations of interest. The stack measurements conducted for three different conditions of plant operation showed that the particle size distributions were bimodal with average modal count median diameters (CMDs) of 24 (SD 4) and 52 (SD 9) nm. The average of all the particle size distributions recorded within the plant sector at a site located 4.5 km from the plant, over the sampling period when the plant was operating, also showed a bimodal distribution. The modal CMDs in this case were 27 and 50 nm, similar to those at the stack. This bimodal size distribution is distinct from the size distribution of the most common ambient anthropogenic emission source, which is vehicle emissions, and can be considered as a signature of this source. The average contribution of the plant (for plant sector winds) was estimated to be (10.0 +/- 3.8) x 10(2) particles cm(-3) and constituted approximately a 50% increase overthe local particle ambient concentration for plant sector winds. This increase in particle number concentration compared to the local background concentration, while high compared to the clean environment concentration, is not significant when compared to concentrations generally encountered in the urban environment of Brisbane.

Correlation of virus replication in tissues with histologic lesions in Atlantic salmon experimentally infected with infectious salmon anemia virus

We have studied the replication of virus in tissues and development of lesions associated with infectious salmon anemia virus (ISAV) infection in Atlantic salmon using in situ hybridization (ISH) with a riboprobe targeting ISAV RNA segment 7 messenger RNA. Fish were infected with three ISAV isolates (U5575-1, RPC-01-0593-1, Norway 810/9/99) and then euthanatized sequentially at 3, 6, 10, and 13 days postinoculation (dpi) and thereafter once a week for 8 weeks. Severe histopathologic lesions were observed in tissues from all groups beginning at the onset of mortality. The severe histopathologic lesions correlated with maximum intensity and frequency of ISH signals (P < 0.001). There was a strong association between the hybridization signals and severity of lesions in the liver, kidney, and heart (R = 0.81, 0.70, and 0.78, respectively; P < 0.001). The distribution of ISH signals indicated the presence of a viremia because signals were observed predominantly in individual blood cells and endothelial cells, and possibly hematopoietic cells of head kidney, but not in the necrotic hepatocytes and renal epithelium. Of the organs sampled, the heart was the first and last to show ISH signals, possibly because of increased activity of the endocardial endothelial cells and the underlining macrophages, which continuously trap and remove circulating virus, and therefore represents the best tissue sample for screening of suspected infected fish. On the basis of mortality, severity of lesions, and intensity and frequency of ISH signals, ISAV isolate Norway 810/9/99 was the most virulent and U5575-1 the least virulent isolate studied.

A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults

BACKGROUND

The incidence and severity of herpes zoster and postherpetic neuralgia increase with age in association with a progressive decline in cell-mediated immunity to varicella-zoster virus (VZV). We tested the hypothesis that vaccination against VZV would decrease the incidence, severity, or both of herpes zoster and postherpetic neuralgia among older adults.

METHODS

We enrolled 38,546 adults 60 years of age or older in a randomized, double-blind, placebo-controlled trial of an investigational live attenuated Oka/Merck VZV vaccine ("zoster vaccine"). Herpes zoster was diagnosed according to clinical and laboratory criteria. The pain and discomfort associated with herpes zoster were measured repeatedly for six months. The primary end point was the burden of illness due to herpes zoster, a measure affected by the incidence, severity, and duration of the associated pain and discomfort. The secondary end point was the incidence of postherpetic neuralgia.

RESULTS

More than 95 percent of the subjects continued in the study to its completion, with a median of 3.12 years of surveillance for herpes zoster. A total of 957 confirmed cases of herpes zoster (315 among vaccine recipients and 642 among placebo recipients) and 107 cases of postherpetic neuralgia (27 among vaccine recipients and 80 among placebo recipients) were included in the efficacy analysis. The use of the zoster vaccine reduced the burden of illness due to herpes zoster by 61.1 percent (P<0.001), reduced the incidence of postherpetic neuralgia by 66.5 percent (P<0.001), and reduced the incidence of herpes zoster by 51.3 percent (P<0.001). Reactions at the injection site were more frequent among vaccine recipients but were generally mild.

CONCLUSIONS

The zoster vaccine markedly reduced morbidity from herpes zoster and postherpetic neuralgia among older adults.

Theoretical and methodological considerations in the measurement of spasticity

PURPOSE

To discuss the measurement of spasticity in the clinical and research environments, make recommendations based on the SPASM reviews of biomechanical, neurophysiological and clinical methods of measuring spasticity and indicate future developments of measurement tools.

METHOD

Using the results of the systematic reviews of the biomechanical, neurophysiological and clinical approaches, methods were evaluated across three dimensions: (1) validity, reliability and sensitivity to change; (2) practical quality such as ease of use and (3) qualities specific to the measurement of spasticity, for example ability to be applied to different muscle groups. Methods were considered in terms of applicability to research and clinical applications.

RESULTS

A hierarchy of measurement approaches was identified from highly controlled and more objective (but unrelated to function) to ecologically valid, but less objective and subject to contamination from other variables. The lack of a precise definition of spasticity may account for the problem of developing a valid, reliable and sensitive method of measurement. The reviews have identified that some tests measure spasticity per se, some phenomena associated with spasticity or consequential to it and others the effect of spasticity on activity and participation and independence.

CONCLUSIONS

Methods appropriate for use in research, particularly into the mechanism of spasticity did not satisfy the needs of the clinician and the need for an objective but clinically applicable tool was identified. A clinical assessment may need to generate more than one 'value' and should include evaluation of other components of the upper motor neurone syndrome. There is therefore a need for standardized protocols for 'best practice' in application of spasticity measurement tools and scales.

Does spasticity result from hyperactive stretch reflexes? Preliminary findings from a stretch reflex characterization study

PURPOSE

To characterize the stretch reflex response of the biceps brachii in stroke patients with elbow spasticity (prior to or within 15 min of treatment with botulinum toxin) and non-impaired volunteers with the aim of quantifying the stretch reflex excitability and observe the differences between the groups.

METHODS

A cross-sectional study. Stretch reflexes from the biceps brachii were elicited following a controlled elbow extension. The amplitude, latency, rise time and duration, calculated from surface EMG recordings from the biceps brachii, were used to characterize the stretch reflex response.

RESULTS

Seventeen non-impaired and 14 stroke patients participated. The amplitude was significantly lower in stroke patients than in non-impaired volunteers (p<0.05). The latency was significantly shorter in stroke patients than in non-impaired volunteers (p<0.05). There were no significant differences in rise time or duration (p>0.10).

DISCUSSION

Reduction in the amplitude in stroke patients was unexpected suggesting the stretch reflex is not necessarily hyper-excitable in people with clinically diagnosed spasticity. Latency differences suggest decreased presynaptic inhibition and/or increased motor neurone excitability can occur following a stroke. However, carry over effects from previous botulinum toxin treatment may have confounded amplitude measurements. Further work evaluating the excitability of the stretch reflex independent of Botulinum toxin and its contribution to resistance to passive stretching is being conducted.

Performance specification for lower limb orthotic devices

OBJECTIVE

To establish the range of forces and moments applied to lower limb orthoses during ambulation by routine users.

DESIGN

Well-established gait analysis techniques were used to determine the loading at the major joints. It was assumed that the joint moments were transmitted by the orthosis encompassing any particular joint. Two hundred and five assessments of 164 patients were successfully completed by a consortium of four gait laboratories in Europe. The orthosis specification and patient clinical data were also recorded.

BACKGROUND

The design and development of orthoses has occurred largely by evolution rather than by formal engineering methods. In particular, formal design has been hampered by a lack of information on the forces and moments applied during ambulation.

METHODS

A standard gait analysis procedure was employed to capture the data. In-house biomechanical models were used to calculate the joint loading. Data were normalised with respect to patient weight and leg length.

RESULTS

It was found that the median maximum normalised ankle moment transmitted by an ankle foot orthosis was 0.15 and the maximum knee moment was 0.09. The greatest moment transmitted by the hip joint of a hip knee ankle foot orthosis was also 0.09. There was a wide variation in the data due to differences in the impairments of the test subjects.

CONCLUSION

It is possible to estimate the loads transmitted by an orthosis using established gait analysis procedures without the need for load measurement transducers. There is now a need both to collect a larger representative dataset and to perform validation studies with transducers.

First Report of Swiss Needle Cast Caused by Phaeocryptopus gaeumannii on Douglas-Fir in Turkey

Two 15-year-old Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) test plantations at Artvin, in the eastern Black Sea Coast Region of Turkey, were inspected in July 2003. Trees in both plantations had yellow-to-brown foliage, and most trees retained only the current year's needles, resulting in sparse tree crowns. Numerous minute, black fruit bodies were present along the rows of stomata on the lower surfaces of needles from both plantations. Laboratory examination revealed that the fruiting bodies that emerged through the stomata were those of Phaeocryptopus gaeumannii [Rohde] Petrak, the causal agent of Swiss needle cast (SNC). Although low infection levels are relatively harmless, heavily infected trees lose all but the current year's foliage, with resulting average volume growth reductions of 23 to 52% (2,3). The pathogen occurs throughout the natural range of Douglas-fir in western North America, where it is native, as well as in eastern North America, Europe, Australia, and New Zealand, where both host and fungus have been introduced (1,2). The pathway of introduction of the pathogen to Turkey is unknown. Douglas-fir is the only known host of P. gaeumannii, and the pathogen is not known to be seedborne. Where P. gaeumannii has been introduced outside of western North America, infected nursery stock has been considered the most probable source (1). However, the affected Artvin plantations were established with seedlings produced in Turkey by using seed obtained from various sources. Earlier Douglas-fir plantations in Turkey date from 1953 and were established by using seed originating from France. The possibility that the pathogen could have arrived with untracked Douglas-fir seedlings from outside Turkey imported by arboreta or private nurseries cannot be excluded. Alternatively, scattered Douglas-fir plantations could have served as links between the Artvin infestation and known infested areas in central and eastern Europe, with spread occurring via windborne ascospores, similar to the spread of the pathogen to Denmark from the British Isles (ca. 1930) (1). Presence of severe SNC infections in Douglas-fir test sites at Artvin could hamper efforts to use this species in operational forestry in Turkey. To our knowledge, this is the first report of the occurrence of Swiss needle cast on Douglas-fir in western Asia. Voucher specimens have been deposited in the Oregon State University herbarium (OSC 106394-106403). References: (1) J. S. Boyce. Phytopathology 30:649, 1940. (2) E. M. Hansen et al. Plant Dis. 84:773, 2000. (3) D. Maguire et al. West. J. Appl. For. 17:86, 2002.

Evolution of catabolic pathways for synthetic compounds: bacterial pathways for degradation of 2,4-dinitrotoluene and nitrobenzene

The pathways for 2,4-dinitrotoluene (2,4-DNT) and nitrobenzene offer fine illustrations of how the ability to assimilate new carbon sources evolves in bacteria. Studies of the degradation pathways provide insight about two principal strategies for overcoming the metabolic block imposed by nitro- substituents on aromatic compounds. The 2,4-DNT pathway uses novel oxygenases for oxidative denitration and subsequent ring-fission. The nitrobenzene pathway links facile reduction of the nitro- substituent, a novel mutase enzyme, and a conserved operon encoding aminophenol degradation for mineralization of nitrobenzene. Molecular genetic analysis with comparative biochemistry reveals how the pathways were assembled in response to the recent appearance of the two synthetic chemicals in the biosphere.

The effect of local-scale physical heterogeneity and nonlinear, rate-limited sorption/desorption on contaminant transport in porous media

Nonideal transport of contaminants in porous media has often been observed in laboratory characterization studies. It has long been recognized that multiple processes associated with both physical and chemical factors can contribute to this nonideal transport behavior. To fully understand system behavior, it is important to determine the relative contributions of these multiple factors when conducting contaminant transport and fate studies. In this study, the relative contribution of physical-heterogeneity-related processes versus those of nonlinear, rate-limited sorption/desorption to the observed nonideal transport of trichloroethene in an undisturbed aquifer core was determined through a series of miscible-displacement experiments. The results of experiments conducted using the undisturbed core, collected from a Superfund site in Tucson, AZ, were compared to those obtained from experiments conducted using the same aquifer material packed homogeneously. The results indicate that both physical and chemical factors, specifically preferential flow and associated rate-limited diffusive mass-transfer and rate-limited sorption/desorption, respectively, contributed to the nonideal behavior observed for trichloroethene transport in the undisturbed core. A successful prediction of trichloroethene transport in the undisturbed core was made employing a mathematical model incorporating multiple sources of nonideal transport, using independently determined model parameters to account for the multiple factors contributing to the nonideal transport behavior. The simulation results indicate that local-scale physical heterogeneity controlled the nonideal transport behavior of trichloroethene in the undisturbed core, and that nonlinear, rate-limited sorption/desorption were of secondary importance.

Outcome measures of spasticity

Spasticity is characterized by a velocity-dependent increase in muscle resistance, in response to a passive stretch. Whilst clinical scales probably represent the most common approach to its measurement, these are limited by poor reliability and difficulties with some definitions. However, recently, a simple system has been used to provide the clinician with a measure of the force applied during the Ashworth Test. The Wartenberg Pendulum Test has been devised for measuring spasticity at the knee, but has been shown to be unsuitable for measuring more severe spasticity. Powered systems have been used in research studies, but are rarely considered suitable for routine clinical use. However, one method of interest, using a low inertia torque motor to measuring stiffness at the wrist, has been shown to provide rapid measurements which correspond to the degree of spasticity defined by other scales. Clinical gait analysis may have an important role to play in assessing spasticity - since there are clear associations between lower limb spasticity and gait problems - but it does not provide a true measure of the condition. In summary, while scales remain the most common method of measuring spasticity, there is considerable potential in instrumented techniques that can provide greater reliability and precision of measurement.

Assessing motor deficits in neurological rehabilitation: patterns of instrument usage

To describe current patterns in the use of clinical scales and measurement technology for the assessment of motor deficits in neurological rehabilitation. Questionnaire, sent to the 2,556 members of the World Forum for Neurological Rehabilitation, distributed over 75 countries. Sixty-eight questionnaires were returned. Generally, participants indicated that the centres where they were based used a number of different clinical assessment scales (median, three), most frequently with a small proportion of patients. The (Modified) Ashworth Scale, the FIM, and the Fugl-Meyer were used most frequently. Only 35 respondents stated that their centre used one or more scales in >75% of their patients, but the choice of such routinely applied instruments varied between centres. The application of measurement technology was restricted, with video and goniometry being used most frequently. The main barriers to more frequent use of assessment tools were perceived to be a lack of resources, information, and training. The (albeit limited) results from this survey suggest that the assessment of motor deficits in neurological rehabilitation is currently mostly qualitative and lacks standardisation. More resources and education are required to support a more routine application of assessment tools and to integrate measurement technology further in neurological rehabilitation to assist in the process of quantification of outcomes.

Biomechanical examination of a commonly used measure of spasticity

BACKGROUND

An increase in the prevalence of neurological disability puts pressure on service providers to restrict costs associated with rehabilitation. Spasticity is an important neurological impairment for which many novel and expensive treatment options now exist. The antispastic effects of these techniques remain unexplored due to a paucity of valid outcome measures.

AIM

To develop a biomechanical measure of resistance to passive movement, which could be used in routine clinical practice, and to examine the validity of the modified Ashworth scale.

STUDY DESIGN

Repeated measure cross-section study on 16 subjects who had a unilateral stroke one-week previously and had no elbow contractures.

OUTCOME MEASURES

Simultaneous measurement of resistance to passive movement using a custom built measuring device and the modified Ashworth scale. Passive range of movement and velocity were also measured. The "catch", a phenomenon associated with the modified Ashworth scale, was identified by the assessor using a horizontal visual analogue scale and biomechanically quantified using the residual calculated from a linear regression technique.

RESULTS

Half the study population had a modified Ashworth score greater than zero. The association between the two measures was poor (kappa=0.366). The speed and range of passive movement were greater in subjects with modified Ashworth score "0" (P<0.05). Resistance to passive movement was higher in the impaired arm (P<0.05) and tended to decrease with repeated measures and increasing speeds.

CONCLUSIONS

A device to measure resistance to passive movement at the elbow was developed. The modified Ashworth scale may not provide a valid measure of spasticity but a measure of resistance to passive movement in an acute stroke population.

RELEVANCE

Spasticity is an important neurological impairment for which many novel and expensive treatment options are being made available. There is a paucity of clinically usable outcomes to measure spasticity. A device to measure resistance to passive movement at the elbow, which was more reliable than the modified Ashworth scale was developed. This device may provide a much needed objective clinical measure to evaluate the efficacy of antispasticity treatment.

Oxidative transformation of aminodinitrotoluene isomers by multicomponent dioxygenases

The electron-withdrawing nitro substituents of 2,4,6-trinitrotoluene (TNT) make the aromatic ring highly resistant to oxidative transformation. The typical biological transformation of TNT involves reduction of one or more of the nitro groups of the ring to produce the corresponding amine. Reduction of a single nitro substituent of TNT to an amino substituent increases the electron density of the aromatic nucleus considerably. The comparatively electron-dense nuclei of the aminodinitrotoluene (ADNT) isomers would be expected to be more susceptible to oxygenase attack than TNT. The hypothesis was tested by evaluating three nitroarene dioxygenases for the ability to hydroxylate the ADNT isomers. The predominant reaction was dioxygenation of the ring to yield nitrite and the corresponding aminomethylnitrocatechol. A secondary reaction was benzylic monooxygenation to form aminodinitrobenzyl alcohol. The substrate preferences and catalytic specificities of the three enzymes differed considerably. The discovery that the ADNT isomers are substrates for the nitroarene dioxygenases reveals the potential for extensive bacterial transformation of TNT under aerobic conditions.

The tyrosine phosphatase SHP-2 is required for mediating phosphatidylinositol 3-kinase/Akt activation by growth factors

SHP-2 is a ubiquitously expressed non-transmembrane tyrosine phosphatase with two SH2 domains. Multiple reverse-genetic studies have indicated that SHP-2 is a required component for organ and animal development. SHP-2 wild-type and homozygous mutant mouse fibroblast cells in which the N-terminal SH2 domain was target-deleted were used to examine the function of SHP-2 in regulating Phosphatidylinositol 3-Kinase (PI3K) activation by growth factors. In addition, SHP-2 and various mutants were introduced into human glioblastoma cells as well as SHP-2(-/-) mouse fibroblasts. We found that EGF stimulation and EGFR oncoprotein (DeltaEGFR) expression independently induced the co-immunoprecipitation of the p85 subunit of PI3K with SHP-2. Targeted deletion of the N-terminal SH2 domain of SHP-2 severely impaired PDGF- and IGF-induced Akt phosphorylation. Ectopic expression of SHP-2 in U87MG gliobastoma cells elevated EGF-induced Akt phosphorylation, and the effect was abolished by mutation of its N-terminal SH2 domain. Likewise, the reconstitution of SHP-2 expression in the SHP-2(-/-) cells enhanced Akt phosphorylation induced by EGF while rescuing that induced by PDGF and IGF. Further lipid kinase activity assays confirmed that SHP-2 modulation of Akt phosphorylation correlated with its regulation of PI3K activation. Based on these results, we conclude that SHP-2 is required for mediating PI3K/Akt activation, and the N-terminal SH2 domain is critically important for a "positive" role of SHP-2 in regulating PI3K pathway activation.

Application of spherical and cylindrical wrapping algorithms in a musculoskeletal model of the upper limb

In the modelling of the upper limb, many muscles cannot be represented as a straight line from origin to insertion due to the complex morphology causing them to wrap around passive structures. The majority of bony contours that form these obstructions can be described adequately as simple geometric shapes such as spheres and cylinders.A novel technique for the parameterisation of muscle paths as they wrap around such shapes has been developed for use in an upper limb model. The new method involves the definition of moving co-ordinate systems in which the path of a wrapped muscle does not move, allowing simplified specification. In addition, an analytical calculation of the wrapping path around a cylinder is presented over previous approximate methods. Muscle moment arms were pre-calculated from vector considerations and within SIMM by tendon excursion. Close agreement between the two suggests that the proposed implementations accurately follow the theoretical relationship and can be used with confidence in musculoskeletal models.

Learning motor control in the upright position: a mechanical engineering approach

Motor control problems that result from damage to the central nervous system can make it difficult to learn functional activities. Although several therapeutic approaches attempt to address such problems there is little evidence of their efficacy. Targeted Training is a new approach, based on a biomechanical analysis of the problem, which usually relies on specifically designed equipment. This paper describes the underlying theory, the development of functional specifications, the translation of these specifications into an engineering design and the clinical results of applying the equipment. The promotion of head and trunk control provides an example of the process.

The design of a five-degree-of-freedom powered orthosis for the upper limb

In response to the need for a sophisticated powered upper-limb orthosis for use by people with disabilities and/or limb weakness or injury, the MULOS (motorized upper-limb orthotic system) has been developed. This is a five-degree-of-freedom electrically powered device having three degrees of freedom at the shoulder, one at the elbow and one to provide pronation/supination. The shoulder mechanism consists of a serial linkage having an equivalent centre of rotation close to that of the anatomical shoulder; this is a self-contained module in which power transmission is provided by tensioned cables. The elbow and pronation/supination modules are also self-contained. The system has been designed to operate under three modes of control: 1. As an assistive robot attached directly to the arm to provide controlled movements for people with severe disability. In this case, it can be operated by a variety of control interfaces, including a specially designed five-degree-of-freedom joystick. 2. Continuous passive motion for the therapy of joints after injury. The trajectory of the joints is selected by 'walk-through' programming and can be replayed for a given number of cycles at a chosen speed. 3. As an exercise device to provide strengthening exercises for elderly people or those recovering from injury or surgery. This mode has not been fully implemented at this stage. In assistive mode, prototype testing has demonstrated that the system can provide the movements required for a range of simple tasks and, in continuous passive motion (CPM) mode, the programming system has been successfully implemented. Great attention has been paid to all aspects of safety. Future work is required to identify problems of operation, and to develop new control interfaces.

Glenohumeral subluxation, scapula resting position, and scapula rotation after stroke: a noninvasive evaluation

OBJECTIVES

To determine whether scapular downward tilt (ScDT) and dynamic scapular lateral rotation (ScLR) in subjects with and without stroke is associated with subluxation, and to prove the reliability of a Scapula Locator System in an elderly population.

DESIGN

Repeated measures of ScLR by 2 observers.

SETTING

Outpatient rehabilitation department of a district general hospital.

PARTICIPANTS

To test device reliability, 5 healthy men (mean age +/- standard deviation, 72 +/- 5 yr). To test scapula position, 30 stroke patients (19 men, 11 women; mean age, 73 +/- 6 yr) and 15 healthy controls (12 men, 3 women; mean age, 62 +/- 6 yr).

INTERVENTIONS

The control subjects' ScDT was compared with stroke subjects' ScDT after stratification according to 3 patterns of ScLR symmetry and the presence of palpable glenohumeral subluxation.

MAIN OUTCOME MEASURES

For device reliability, 3-way analysis of variance. For scapula position, triangulated location by Scapula Locator System of acromion, inferior angle, and root of the scapular spine; then measurement of scapula motion to determine symmetry, lag, or lead.

RESULTS

The inter- and intraobserver reliability of the Scapula Locator System device was high (1% of variance each). Normal ScDT was positive (left side: 10.94 degrees +/- 2.62 degrees; right side: 9.69 degrees +/- 4.36 degrees ), indicating a downward-facing glenoid fossa. This finding was unchanged by stroke (10.46 degrees +/- 2.42 degrees ). All controls and 16 stroke subjects had symmetry between shoulders for ScLR rate and ScDT. Two other patterns (p <.01) of ScLR were found after stroke: 8 subjects had a slower rate of affected arm ScLR (lag) with a correspondingly greater ScDT on the affected side (2.61 degrees +/- 6.7 degrees ); 6 subjects had a faster rate of affected arm ScLR (lead) but with an upward-facing glenoid fossa on the affected side (ScDT: -11.84 degrees +/- 8.48 degrees ). No significant inter- or intrasubject difference in ScDT existed in the 6 cases of glenohumeral subluxation.

CONCLUSIONS

The scapula normally tilts downward with or without stroke. The effect of stroke is similar on tonic (ScDT) and phasic (ScLR) control of scapula position. Subluxation is not linked with a particular scapular resting position after stroke.

Abdominal aortic aneurysm in women

OBJECTIVE

The purpose of this study was to compare abdominal aortic aneurysm (AAA) associations in men and women.

METHODS

Veterans aged 50 to 79 years without a previous history of AAA underwent ultrasound screening for AAA after completing a questionnaire on demographic information and potential risk factors.

RESULTS

A total of 122,272 men and 3450 women were successfully screened. An AAA of 3.0 cm or greater in diameter was found in 4.3% of men and 1.0% of women (P <.001). Contrary to a previous report, we did not find suprarenal aortic enlargement accompanying AAA to be more common in women. The principal associations that we have previously reported for AAA in this cohort (age, smoking, family history of AAA, and a negative association with diabetes) were all similar in women compared with men. In age- and smoking-adjusted models, the interaction terms indicated that black race and cancer were more strongly associated with AAA in women than men (P <.05). Height and cerebral vascular disease were also more strongly associated with AAA in women than in men, but these interaction terms did not reach statistical significance (P <.10). Although the other differences were unexpected and require confirmation, the trend toward a stronger association of cerebral vascular disease with AAA in women is consistent with two previous reports.

CONCLUSIONS

Despite the much lower prevalence of AAA in women, the most important associations with AAA are similar to those seen in men. Our data provide some support for a previous finding that cerebrovascular disease may be more closely associated with AAA in women than in men.