Injury Risk Functions for the Midsized Male Wrist and Elbow as a Result of Behind Shield Blunt Trauma.

Ballistic shields protect users from a variety of threats, including projectiles. Shield back-face deformation (BFD) is the result of the shield deflecting or absorbing a projectile and deforming toward the user. Back-face deformation can result in localized blunt loading to the upper extremity, where the shield is supported by the user. Two vulnerable locations along the upper extremity were investigated-the wrist and elbow-on eight postmortem human subjects (PMHS) using a pneumatic impacting apparatus for investigating the fracture threshold as a result of behind shield blunt trauma (BSBT). Impacting parameters were established by subjecting an augmented WorldSID anthropomorphic test device (ATD) positioned behind a ballistic shield to ballistic impacts. These data were used to form the impact parameters applied to PMHS, where the wrist most frequently fractured at the distal radius and the elbow most frequently fractured at the radial head. The fracture threshold for the wrist was 5663±1386 N (mean±standard deviation), higher than the elbow at 4765±894 N (though not significantly, p = 0.15). The failure impact velocity for wrist impacts was 17.7±2.1 m/s, while for the elbow, the failure impact velocity was 19.5±0.9 m/s. An approximate 10% risk of fracture threshold was identified on the modified WorldSID ATD (no flesh analogue included) to inform future protective standards.

Mycoplasma bovis testing for the screening of semen imported into New Zealand.

AIMS: To evaluate the fitness of three PCR assays for the detection of Mycoplasma bovis in dilute (extended) bovine semen, and a reverse transcriptase-PCR (RT-PCR) adaptation as a proxy for viability. MATERIALS AND METHODS: Four commercial kit-based methods for nucleic acid extraction were compared to test for the presence of PCR inhibitors in nucleic acid extracted from undiluted and diluted semen. Then, analytical sensitivity, analytical specificity, and diagnostic specificity of two real-time PCR and one conventional PCR were evaluated for the detection of M. bovis DNA in semen and compared against microbial culture. Furthermore, an RT-PCR was adapted to detect RNA only and tested on viable and non-viable M. bovis to establish its ability to discriminate between the two. RESULTS: No significant PCR inhibition was detected from the dilute semen. All DNA extraction methods except one were equivalent, regardless of semen dilution. The analytical sensitivity of the real-time PCR assays was estimated as 45.6 cfu per 200 µL semen straw (2.2 × 102 cfu/mL). The conventional PCR was 10 times less sensitive. No cross-reactivity was observed for the real-time PCR for any of the bacteria tested and the diagnostic specificity was estimated as 100 (95% CI = 94.04-100) %. The RT-PCR was poor in distinguishing between viable and non-viable M. bovis. The mean quantification cycle (Cq) values for RNA extracted from different treatments to kill M. bovis remained unchanged 0-48 hours after inactivation. CONCLUSION AND CLINICAL RELEVANCE: The real-time PCR were fit for the purpose of screening dilute semen for the detection of M. bovis to prevent incursion via importation of infected semen. The real-time PCR assays can be used interchangeably. The RT-PCR could not reliably indicate the viability of M. bovis. Based on the results from this study, a protocol and guidelines have been produced for laboratories elsewhere that wish to test bovine semen for M. bovis.

Recurrent life-threatening reactions to platelet transfusion in an aplastic anaemia patient with a paroxysmal nocturnal haemoglobinuria clone.

A 60-year-old woman was diagnosed with non-severe aplastic anaemia when she presented with anaemia and thrombocytopenia. She developed recurrent life-threatening hypotensive reactions during transfusion of leukodepleted platelet concentrates, and washed platelet concentrates prevented the development of such reactions subsequently. A paroxysmal nocturnal haemoglobinuria clone was detected on investigating for aplastic anaemia, which has been speculated to play a role in the recurrent hypotensive reactions.

Injury Risk for the Hand and Forearm Under Loading Representative of Behind Shield Blunt Trauma.

Ballistic shields protect users from a variety of threats, including projectiles. Shield back-face deformation (BFD) is the result of the shield absorbing energy from a projectile and deforming towards the user. Back-face deformation can result in localized blunt loading to the upper extremity, where the shield is supported by the user and may cause injury through behind armour blunt trauma (BABT) mechanisms. Post-mortem human subject (PMHS) responses are critical to identify the injury risk in these high-rate scenarios and are used to quantify the injury tolerance. Two vulnerable locations along the upper extremity were investigated-the hand and forearm-using eight PMHS to identify the fracture threshold resulting from shield BABT loading conditions. Impacts delivered to the hand at 16.4 ± 0.8 m/s resulted in failure loads of 3818 ± 897 N, whilst the forearm impacts delivered at a similar velocity of 16.9 ± 1.9 m/s had lower failure loads at 3011 ± 656 N. The corresponding 10% risk of hand and forearm fractures (as measured on a modified WorldSID Anthropomorphic Test Device) were identified as 11.0 kN and 8.1 kN, respectively, which should be used when evaluating future designs of composite ballistic shields. This study is the first known investigation of the upper extremity to this high loading rate scenario and provides the foundation for future biomechanical research in the area of behind shield blunt trauma.

The effects of chlorhexidine, povidone-iodine and vancomycin on growth and biofilms of pathogens that cause prosthetic joint infections: an in-vitro model.

BACKGROUND: Chlorhexidine gluconate (CHG) and povidone-iodine (PI) are commonly used to prevent prosthetic joint infection (PJI) during total joint replacement; however, their effective concentrations and impact on biofilms are not well defined. AIM: To determine: (1) the in-vitro minimum inhibitory concentration of CHG and PI against model PJI-causing organisms and clinical isolates; (2) their impact on biofilm formation; (3) whether there is a synergistic benefit to combining the two solutions; and (4) whether adding the antibiotic vancomycin impacts antiseptic activity. METHODS: We measured in-vitro growth and biofilm formation of Staphylococcus epidermidis, meticillin-sensitive and meticillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, as well as recent clinical isolates, in the presence of increasing concentrations of CHG and/or PI. Checkerboard assays were used to measure potential synergy of the solutions together and with vancomycin. FINDINGS: CHG and PI inhibited growth and biofilm formation of all model organisms tested at concentrations of 0.0004% and 0.33% or lower, respectively; highly dilute concentrations paradoxically increased biofilm formation. The solutions did not synergize with one another and acted independently of vancomycin. CONCLUSION: CHG and PI are effective at lower concentrations than typically used, establishing baselines to support further clinical trials aimed at optimizing wound disinfection. There is no synergistic advantage to using both in combination. Vancomycin is effective at inhibiting the growth of S. epidermidis and S. aureus; however, it stimulates P. aeruginosa biofilm production, suggesting in the rare case of P. aeruginosa PJI, it could exacerbate infection.

Behind Shield Blunt Trauma: Characterizing the Back-Face Deformation of Shields with a Focus on Upper Limb Loading.

Shield back-face deformation (BFD) is the result of composite ballistic shields deflecting or absorbing a projectile's energy and deforming towards the user. BFD can result in localized loading to the upper extremity, where the shield is secured to the user. An augmented anthropomorphic test device upper extremity was used to quantify this applied load. Four locations along the upper extremity were tested-the hand, wrist, forearm, and elbow-for investigating differing boundary conditions and their effect on resultant load. Varying stand-off distances, the distance between the back of the shield and the force sensor, were investigated. Digital image correlation was also conducted to measure the dynamic displacement of the shield. The mean peak back-face velocity of the shield was 208.4 ± 38.8 m/s, while the average affected area was 1505 ± 158.3 mm2. Impulse was not significantly affected by anatomical location for the same stand-off distance; however, as stand-off distance decreased, the measured force significantly increased (p < 0.05). Notably, impact duration did not differ significantly for any of the impact scenarios. This is the first step in developing injury criteria for this region resulting from behind shield blunt trauma, and these data will be used for developing injury thresholds in post-mortem human surrogates.

Characterization of the PilN, PilO and PilP type IVa pilus subcomplex.

Type IVa pili are bacterial nanomachines required for colonization of surfaces, but little is known about the organization of proteins in this system. The Pseudomonas aeruginosa pilMNOPQ operon encodes five key members of the transenvelope complex facilitating pilus function. While PilQ forms the outer membrane secretin pore, the functions of the inner membrane-associated proteins PilM/N/O/P are less well defined. Structural characterization of a stable C-terminal fragment of PilP (PilP(Δ71)) by NMR revealed a modified ß-sandwich fold, similar to that of Neisseria meningitidis PilP, although complementation experiments showed that the two proteins are not interchangeable likely due to divergent surface properties. PilP is an inner membrane putative lipoprotein, but mutagenesis of the putative lipobox had no effect on the localization and function of PilP. A larger fragment, PilP(Δ18-6His), co-purified with a PilN(Δ44)/PilO(Δ51) heterodimer as a stable complex that eluted from a size exclusion chromatography column as a single peak with a molecular weight equivalent to two heterotrimers with 1:1:1 stoichiometry. Although PilO forms both homodimers and PilN-PilO heterodimers, PilP(Δ18-6His) did not interact stably with PilO(Δ51) alone. Together these data demonstrate that PilN/PilO/PilP interact directly to form a stable heterotrimeric complex, explaining the dispensability of PilP's lipid anchor for localization and function.

Ovine FABP4 Variation and Its Association With Flystrike Susceptibility.

Flystrike is a major cost and a welfare issue for the New Zealand sheep industry. There are several factors that can predispose sheep to flystrike, such as having fleecerot, a urine-stained breech, and "dags" (an accumulation of fecal matter in the wool of the breech). The FABP4 gene (FABP4) has been associated with variation in ovine fleecerot resistance, with a strong genetic correlation existing between fleecerot and flystrike occurrence. In this study, blood samples were collected from sheep with and without flystrike for DNA typing. PCR-SSCP analyses were used to genotype two regions of ovine FABP4. Sheep with the A 1 variant of FABP4 were found to be less likely (odds ratio 0.689, P = 0.014) to have flystrike than those without A 1. The likelihood of flystrike occurrence decreased as copy number of A 1 increased (odds ratio 0.695, P = 0.006). This suggests that FABP4 might be a candidate gene for flystrike resilience in sheep, although further research is required to verify this association.

Situational analysis of varying models of adherence support and loss to follow up rates; findings from 27 treatment facilities in eight resource limited countries.

OBJECTIVES: Large-scale provision of ART in the absence of viral load monitoring, resistance testing, and limited second-line treatment options places adherence support as a vital therapeutic intervention. We aimed to compare patient loss to follow up rates with the degree of adherence support through a retrospective review of patients enrolled in the AIDSRelief program between August 2004 and June 2005. METHODS: Loss to follow up data were analysed and programs were categorised into one of four tiered levels of adherence support models: Tier I, II, III, and IV which increase from lowest to highest support. Bivariate and t-test analyses were used to test for significant differences between the models. RESULTS: 13,391 patients at 27 treatment facilities from six African and two Caribbean countries began antiretroviral therapy within the first year of the AIDSRelief program. The mean loss to follow up within the first year was 7.5%. Eight facilities were Tier I, three (Tier II), nine (Tier III), and seven (Tier IV). Facilities in Tier I had a loss to follow up rate of 14%, Tier II (10%), Tier III (5%), and Tier IV (1%). The proportion of loss to follow up for Tier I and Tier III were significantly different from each other (P < 0.02), as were Tier I and Tier IV (P < 0.006). There were differences between Tier II and Tier IV (P < 0.009) as well as Tier III and Tier IV (P < 0.017). CONCLUSION: These data strongly support the use of proactive adherence support programs, beyond routine patient counselling and defaulter tracking to support the'public health approach'to ART.

A survey of the management of needlestick injuries from incapacitated patients in intensive care units.

The Human Tissue Act 2004 and Mental Capacity Act 2005 resulted in a change in the management of needlestick injuries sustained from incapacitated patients. It appears unlawful to test for blood-borne viruses without a patient's consent for the sole benefit of the healthcare worker. This survey of intensive care units within England, Wales and Northern Ireland investigated how needlestick injuries from incapacitated patients had been managed within the previous year. Of the 225 intensive care units surveyed, 99 (44%) responded. Sixty-two (62.6%) reported a needlestick injury to a healthcare worker from an incapacitated patient. Thirty-six (64.3%) patients were tested for blood-borne viruses without consent. Sixteen (25.8%) patients tested positive for blood-borne viruses. Only 19 (30.6%) healthcare workers took post-exposure prophylaxis following the injury. These results show that needlestick injuries from incapacitated patients are common and that the majority of patients were tested for blood-borne viruses without consent.

Genetics of O-antigen biosynthesis in Pseudomonas aeruginosa.

Pathogenic bacteria produce an elaborate assortment of extracellular and cell-associated bacterial products that enable colonization and establishment of infection within a host. Lipopolysaccharide (LPS) molecules are cell surface factors that are typically known for their protective role against serum-mediated lysis and their endotoxic properties. The most heterogeneous portion of LPS is the O antigen or O polysaccharide, and it is this region which confers serum resistance to the organism. Pseudomonas aeruginosa is capable of concomitantly synthesizing two types of LPS referred to as A band and B band. The A-band LPS contains a conserved O polysaccharide region composed of D-rhamnose (homopolymer), while the B-band O-antigen (heteropolymer) structure varies among the 20 O serotypes of P. aeruginosa. The genes coding for the enzymes that direct the synthesis of these two O antigens are organized into two separate clusters situated at different chromosomal locations. In this review, we summarize the organization of these two gene clusters to discuss how A-band and B-band O antigens are synthesized and assembled by dedicated enzymes. Examples of unique proteins required for both A-band and B-band O-antigen synthesis and for the synthesis of both LPS and alginate are discussed. The recent identification of additional genes within the P. aeruginosa genome that are homologous to those in the A-band and B-band gene clusters are intriguing since some are able to influence O-antigen synthesis. These studies demonstrate that P. aeruginosa represents a unique model system, allowing studies of heteropolymeric and homopolymeric O-antigen synthesis, as well as permitting an examination of the interrelationship of the synthesis of LPS molecules and other virulence determinants.

Conserved, unstructured regions in Pseudomonas aeruginosa PilO are important for type IVa pilus function.

Pseudomonas aeruginosa uses long, thin fibres called type IV pili (T4P) for adherence to surfaces, biofilm formation, and twitching motility. A conserved subcomplex of PilMNOP is required for extension and retraction of T4P. To better understand its function, we attempted to co-crystallize the soluble periplasmic portions of PilNOP, using reductive surface methylation to promote crystal formation. Only PilOΔ109 crystallized; its structure was determined to 1.7 Å resolution using molecular replacement. This new structure revealed two novel features: a shorter N-terminal α1-helix followed by a longer unstructured loop, and a discontinuous ß-strand in the second αßß motif, mirroring that in the first motif. PISA analysis identified a potential dimer interface with striking similarity to that of the PilO homolog EpsM from the Vibrio cholerae type II secretion system. We identified highly conserved residues within predicted unstructured regions in PilO proteins from various Pseudomonads and performed site-directed mutagenesis to assess their role in T4P function. R169D and I170A substitutions decreased surface piliation and twitching motility without disrupting PilO homodimer formation. These residues could form important protein-protein interactions with PilN or PilP. This work furthers our understanding of residues critical for T4aP function.

Independent prescriber physiotherapist led balance clinic: the Southport and Ormskirk pathway.

OBJECTIVE: To report the introduction and impact of non-medical prescribing, initiated to improve patient pathways for those presenting with dizziness and balance disorders. METHODS: The Southport and Ormskirk physiotherapy-led vestibular clinic sees and treats all patients with dizziness and balance disorders referred to the ENT department. Letters are triaged by an audiologist, who also performs an otological examination and hearing test; this is followed by an assessment with the independent prescriber physiotherapist. An ENT consultant is nearby if joint consultation is needed. Diagnoses, treatments and patient satisfaction were studied, with an analysis of the impact of medication management (stopping or starting medicines) on patients and service. RESULTS: In 12 months, 413 new patients with dizziness and balance disorders had appointments. The most common diagnoses were benign paroxysmal positional vertigo and vestibular migraine. Eighty-four per cent of patients required self-management strategies, 50 per cent exercise therapy, 48 per cent medication management and 24 per cent a particle repositioning manoeuvre. Patient satisfaction was high (99 per cent). CONCLUSION: Having an independent prescriber physiotherapist leading the balance clinic has reduced the number of hospital visits and onward referrals. Nearly half of all patients required medication management as part of their dizziness or balance treatment.

Association between variation in faecal egg count for a natural mixed field-challenge of nematode parasites and TLR4 variation.

Research has shown that Toll-like receptor 4 (TLR4) is important in immune responses to some helminth parasites. In sheep, variation in the PAMP region of TLR4 may result in structurally and thus functionally different TLR4 molecules, and this may consequently lead to variation in the TLR4 response to parasite infections. This study involved three separate, but related sheep breeds (Merino, Polwarth and Corriedale sheep) and a total of 885 lambs from five New Zealand farms that underwent a mixed field-challenge from gastro-intestinal parasites. Faecal samples were collected at approximately 4 and 9 months of age and faecal egg counts (FECs) for Nematodirus spp. and Strongyle species determined, along with the total number of eggs per gram (EPG). Analysis of the five farms collectively revealed an association (P=0.023) between the presence of TLR4 variant *02 (mean 24 EPG) and the absence of the variant (mean 32 EPG) at 9 months of age. Conversely the presence of *03 had a significantly (P=0.047) higher mean Nematodirus spp. FEC (mean 42 EPG) compared to the absence (mean 28 EPG) at 9 months of age. More associations were revealed when the data were split according to the dominant faecal parasite species. With a predominantly Trichostrongylus spp. FEC group of lambs at 9 months of age, the presence of TLR4 variant *02 was found to have significantly (P=0.003) lower Nematodirus spp. FEC (mean 4 EPG), and also significantly (P=0.033) lower total FEC (mean 312 EPG) when compared to sheep without the variant (mean 15 EPG and 449 EPG, respectively). The presence of TLR4 variant *03 and *04 were associated or tended to be associated (P=0.010 and P=0.088, respectively) with higher Nematodirus spp. FEC (mean 25 EPG and 22 EPG, respectively) when compared to lambs without the variant (mean 10 EPG and 11 EPG, respectively). These results suggest that TLR4 variation may be affecting the immune response to gastro-intestinal parasites in sheep, although principally to Nematodirus spp. infections and not Strongyle species infections.

Adjuvant interferon in high-risk melanoma: the AIM HIGH Study--United Kingdom Coordinating Committee on Cancer Research randomized study of adjuvant low-dose extended-duration interferon Alfa-2a in high-risk resected malignant melanoma.

PURPOSE: To evaluate low-dose extended duration interferon alfa-2a as adjuvant therapy in patients with thick (> or = 4 mm) primary cutaneous melanoma and/or locoregional metastases. PATIENTS AND METHODS: In this randomized controlled trial involving 674 patients, the effect of interferon alfa-2a (3 megaunits three times per week for 2 years or until recurrence) on overall survival (OS) and recurrence-free survival (RFS) was compared with that of no further treatment in radically resected stage IIB and stage III cutaneous malignant melanoma. RESULTS: The OS and RFS rates at 5 years were 44% (SE, 2.6) and 32% (SE, 2.1), respectively. There was no significant difference in OS or RFS between the interferon-treated and control arms (odds ratio [OR], 0.94; 95% CI, 0.75 to 1.18; P =.6; and OR, 0.91; 95% CI, 0.75 to 1.10; P =.3; respectively). Male sex (P =.003) and regional lymph node involvement (P =.0009), but not age (P =.7), were statistically significant adverse features for OS. Subgroup analysis by disease stage, age, and sex did not show any clear differences between interferon-treated and control groups in either OS or RFS. Interferon-related toxicities were modest: grade 3 (and in only one case, grade 4) fatigue or mood disturbance was seen in 7% and 4% respectively, of patients. However, there were 50 withdrawals (15%) from interferon treatment due to toxicity. CONCLUSION: The results from this study, taken in isolation, do not indicate that extended-duration low-dose interferon is significantly better than observation alone in the initial treatment of completely resected high-risk malignant melanoma.

A randomized double-blind study of fluoxetine versus placebo in the treatment of dysthymia.

OBJECTIVE: The purpose of this study was to assess the efficacy of fluoxetine, a selective serotonergic antidepressant, in the treatment of dysthymia. METHOD: Thirty-five patients who met criteria for dysthymia, but not major depression, began randomized, double-blind 8-week trials of fluoxetine or placebo. RESULTS: Of 32 patients who completed the study, 10 (62.5%) of the 16 patients given fluoxetine and three (18.8%) of the 16 given placebo responded to treatment. Response was defined as 1) 50% or greater decrease in Hamilton Rating Scale for Depression score and 2) a score of 1 or 2 on the Clinical Global Impression (CGI) improvement subscale. Fluoxetine subjects showed significantly greater improvement at week 8 than placebo subjects on the Hamilton depression and CGI scales, but not on the Hopkins Symptom Check-list (58-item) or the Cornell Dysthymia Rating Scale. CONCLUSIONS: When compared to placebo, fluoxetine showed short-term effectiveness in treating dysthymic symptoms.

Production of recombinant soluble human integrin alpha4beta1.

Integrin alpha4beta1 is a major leukocyte adhesion receptor that is a key target for the development of anti-inflammatory therapeutics. With the dual long-term goals of developing a reagent for use in high-throughput inhibitor screening assays and for crystallisation trials and subsequent structure determination, we have generated a recombinant soluble alpha4beta1 receptor. Both subunits were truncated prior to the transmembrane domains by site-directed mutagenesis and expressed using baculovirus infection of insect cells. The molecular weights of the recombinant subunits were as expected for post-translationally unmodified protein. In addition, as observed for the native subunit, a proportion of the alpha4 subunit was proteolytically processed into two fragments. ELISA and solid phase ligand-binding assays were performed to investigate the folding and functionality of the soluble integrin. The data suggest that the receptor was correctly folded and that it bound recombinant ligands with similar kinetics to the native molecule.

Regulation of the extracellular ligand binding activity of integrins.

Integrins are a large heterodimeric family of cell surface adhesion receptors that bind extracellular matrix and cell surface ligands. The extracellular ligand binding activity of integrins is a dynamic and highly regulated event involving the induction of conformational changes within the integrin structure. The adhesive properties of integrins can be controlled by altering the activation state of the integrin, either through conformational change or receptor clustering, using mechanisms that are regulated by intracellular proteins. In this review, we will discuss what is currently known about integrin structure and the ligand binding sites present within the receptor. In addition, the mechanisms by which the ligand binding event is regulated through conformational change will be addressed, and the potential role of intracellular cytoplasmic proteins will be discussed.