Biomechanical and ergonomic risks associated with cervical musculoskeletal dysfunction amongst surgeons: A systematic review

INTRODUCTION

Surgeons are at high risk of developing musculoskeletal symptoms due to a range of factors including, maladaptive positioning and surgical ergonomics. Cervical muscle strain and biomechanical load is most prevalent due to repetitive motions and prolonged static neck positioning. This issue is apparent through reports of prevalence between 10 and 74.4% among surgeons. The aim of this systematic review is to provide an objective assessment of the clinical evidence available and a descriptive analysis of the effects of kinematics and surgical ergonomics on the prevalence of surgeons' cervical musculoskeletal pain.

METHODS

This is PRISMA-compliant systematic review of clinical studies assessing the prevalence of cervical musculoskeletal dysfunction in surgeons by searching PUBMED and Ovid EMBASE databases from inception to 19th October 2023. Study quality was graded according to the National Institutes of Health study quality assessment tools.

RESULTS

A total of 9 studies were included in the final qualitative analysis. The use of loupes, open surgery and excessive neck flexion (>30°) were associated with cervical dysfunction. Comparison of study outcomes was challenging due to heterogeneity within study methods and the paucity of methodological quality.

CONCLUSION

The current literature assessing ergonomic and biomechanical factors predisposing surgeons to cervical musculoskeletal dysfunction is insufficient to provide reliable guidance for clinicians. Although the literature identifies factors contributing to work-related cervical dysfunction, few attempt to evaluate interventions for improved surgical ergonomics. An objective assessment of interventions that prompt postural correction with the aim to improve neck pain in surgeon cohorts is warranted.

The correlation between altmetric score and traditional measures of article impact for studies pertaining to spine trauma

PURPOSE

It is becoming increasingly common for researchers to share scientific literature via social media. Traditional bibliometrics have long been utilized to measure a study's academic impact, but they fail to capture the impact generated through social media sharing. Altmetric Attention Score (AAS) is a weighted count of all the online attention garnered by a study, and it is currently unclear whether a relationship with traditional bibliometrics exists.

METHODS

We identified the five highest-rated spine-specific and five highest-rated general orthopedic journals by Scopus CiteScore 2020. We then identified all the spine trauma studies across a 5-year span (2016-2020) within these journals and compared AAS with traditional bibliometrics using Independent t-tests and Pearson's correlational analyses.

RESULTS

No statistically significant relationships were identified between AAS and traditional bibliometrics for articles pertaining to spine trauma: Level of Evidence (R = - 0.02, p = 0.34), H-Index Primary Author (R =  < - 0.01, p = 0.50), H-Index Senior Author (R = - 0.04, p = 0.24), and Number of Citations (R = 0.01, p = 0.40). The top five articles by AAS include those pertaining to motorcycle injuries (AAS = 687), orthosis in thoracolumbar fractures (AAS = 199), golfing injuries (AAS = 166), smartphone-based teleradiology (AAS = 41), and auto racing injuries (AAS = 39).

CONCLUSION

The lack of overlap between these types of metrics suggests that AAS or similar alternative metrics should be used to measure an article's social impact. The social impact of an article should likewise be a factor in determining an article's overall impact along with its academic impact as measured by bibliometrics.

CRISPR-Cas9 In Vivo Gene Editing of KLKB1 for Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a rare genetic disease that leads to severe and unpredictable swelling attacks. NTLA-2002 is an in vivo gene-editing therapy based on clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9. NTLA-2002 targets the gene encoding kallikrein B1 (KLKB1), with the goal of lifelong control of angioedema attacks after a single dose.

METHODS

In this phase 1 dose-escalation portion of a combined phase 1-2 trial of NTLA-2002 in adults with hereditary angioedema, we administered NTLA-2002 at a single dose of 25 mg, 50 mg, or 75 mg. The primary end points were the safety and side-effect profile of NTLA-2002 therapy. Secondary and exploratory end points included pharmacokinetics, pharmacodynamics, and clinical efficacy determined on the basis of investigator-confirmed angioedema attacks.

RESULTS

Three patients received 25 mg of NTLA-2002, four received 50 mg, and three received 75 mg. At all dose levels, the most common adverse events were infusion-related reactions and fatigue. No dose-limiting toxic effects, serious adverse events, grade 3 or higher adverse events, or clinically important laboratory findings were observed after the administration of NTLA-2002. Dose-dependent reductions in the total plasma kallikrein protein level were observed between baseline and the latest assessment, with a mean percentage change of -67% in the 25-mg group, -84% in the 50-mg group, and -95% in the 75-mg group. The mean percentage change in the number of angioedema attacks per month between baseline and weeks 1 through 16 (primary observation period) was -91% in the 25-mg group, -97% in the 50-mg group, and -80% in the 75-mg group. Among all the patients, the mean percentage change in the number of angioedema attacks per month from baseline through the latest assessment was -95%.

CONCLUSIONS

In this small study, a single dose of NTLA-2002 led to robust, dose-dependent, and durable reductions in total plasma kallikrein levels, and no severe adverse events were observed. In exploratory analyses, reductions in the number of angioedema attacks per month were observed at all dose levels. (Funded by Intellia Therapeutics; ClinicalTrials.gov number, NCT05120830.).

Response to "isolated head tremor: A DAT SPECT and somatosensory temporal discrimination study."

In response to Ferrazano and colleagues' observation of normal DAT binding in patients with isolated head tremor but with abnormal STDT, we report normal 123-IBZM SPECT in a cohort of patients with adult-onset idiopathic focal dystonia with cervical dystonia and their unaffected first-degree relatives both with normal and abnormal TDTs. We discuss molecular imaging findings in dystonia.

931 COVID-19 and the Irish National Spinal Injuries Unit: Impact on Service Provision and Strategies to Protect Urgent Care

Introduction

The COVID-19 pandemic has had a dramatic impact on the provision of healthcare worldwide. The delivery of a national spinal service for emergent surgery, elective surgery and outpatient assessment has been incredibly challenging.

Method

Prospectively collected data regarding referrals to, and operative workload of, the Irish National Spinal Injuries Unit (NSIU) during the period of national lockdown in response to the COVID-19 pandemic was compared to the same period in 2019.

Results

During the period of national lockdown there was a 47% decrease in the number of urgent referrals to the NSIU and a 61% reduction in the number of surgical cases performed. A particularly concerning finding was that for surgical cases there was a 400% increase in attempted suicide as the cause of injury with this cohort representing 11% of all surgical cases performed during the pandemic lockdown. The introduction of a national instant messaging application (Siilo) referral group resulted in a median time to first response by a National Spinal Injuries Unit (NSIU) surgeon of 15.5 minutes.

Conclusions

The COVID-19 pandemic has had a significant impact on the provision of a national spinal service, however innovative strategies have been adopted to protect the capacity to provide urgent care.

A randomised trial of bilateral erector spinae plane block vs. no block for thoracolumbar decompressive spinal surgery

Major spinal surgery causes significant postoperative pain. We tested the efficacy and safety of bilateral erector spinae block on quality of recovery and pain after thoracolumbar decompression. We randomly allocated 60 adults to standard care or erector spinae block. Erector spinae block improved the mean (SD) quality of recovery-15 score at 24 postoperative hours, from 119 (20) to 132 (14), an increase (95%CI) of 13 (4-22), p = 0.0044. Median (IQR [range]) comprehensive complication index was 1 (0-3 [0-5]) in the control group vs. 1 (0-1 [0-4]) after block, p = 0.4. Erector spinae block reduced mean (SD) area under the curve pain during the first 24 postoperative hours: at rest, from 78 (49) to 50 (39), p = 0.018; and on sitting, from 125 (51) to 91 (50), p = 0.009. The cumulative mean (SD) oxycodone consumption to 24 h was 27 (18) mg in the control group and 19 (26) mg after block, p = 0.20. In conclusion, erector spinae block improved recovery and reduced pain for 24 h after thoracolumbar decompression surgery.

Global loss of Tfr2 with concomitant induced iron deficiency greatly ameliorates the phenotype of a murine thalassemia intermedia model

β-thalassemias result from mutations in β-globin, causing ineffective erythropoiesis and secondary iron overload due to inappropriately low levels of the iron regulatory hormone hepcidin. Mutations in transferrin receptor 2 (TFR2) lead to hereditary hemochromatosis (HH) as a result of inappropriately increased iron uptake from the diet, also due to improperly regulated hepcidin. TFR2 is also thought to be required for efficient erythropoiesis through its interaction with the erythropoietin receptor in erythroid progenitors. Transmembrane serine protease 6 (TMPRSS6), a membrane serine protease expressed selectively in the liver, participates in regulating hepcidin production in response to iron stores by cleaving hemojuvelin (HJV). We have previously demonstrated that inhibiting TMPRSS6 expression with a hepatocyte-specific siRNA formulation, induces hepcidin, mitigates anemia, and reduces iron overload in murine models of β-thalassemia intermedia and HH. Here, we demonstrate that Tmprss6 siRNA treatment of double mutant Tfr2^Y245X/Y245X HH Hbb^th3/+ thalassemic mice induces hepcidin and diminishes tissue and serum iron levels. Importantly, treated double mutant animals produce more mature red blood cells and have a nearly 50% increase in hemoglobin compared to untreated β-thalassemic mice. Furthermore, we also show that treatment of Tfr2^Y245X/Y245X HH mice leads to increased hepcidin expression and reduced total body iron burden. These data indicate that siRNA suppression of Tmprss6, in conjunction with the targeting of TFR2, may be superior to inhibiting Tmprss6 alone in the treatment of the anemia and secondary iron loading in β-thalassemia intermedia and may be useful as a method of suppressing the primary iron overload in TFR2-related (type 3) hereditary hemochromatosis.

Auto-Decompression - Preserved Neurological Function in Bilateral Cervical Facet Dislocations

Introduction Bilateral cervical facet dislocation (BCFD) is an uncommon injury with a high incidence of severe neurological impairment. We describe 4 cases of BCFD with preserved neurological function. Cases Case 1: A 78-year-old female who suffered two ground level falls (GLFs). Pre-operative American Spinal Injury Association (ASIA) Score was C5D. Imaging revealed a BCFD at C6/C7 and a C6 laminar fracture. Case 2: A 63-year-old male suffered a fall down 14 steps. Pre-operative ASIA score was E. Imaging demonstrated a BCFD at C7/T1, and a C6 laminar fracture. Case 3: A 46-year-old male collided with a tree while descending a hill on a bicycle. Pre-operative ASIA score was C6D. Imaging revealed a BCFD at C7/T1 and a C7 laminar fracture. Case 4: A 67-year-old male suffered a GLF while exiting a stationary car. Pre-operative ASIA score on admission was E. Imaging revealed a BCFD at C6/C7 with bilateral laminar fractures at C5 and C6. Outcome All cases underwent 2-stage surgical fixation. All cases maintained or had an improved ASIA score post-operatively. Conclusion In all cases, the presence of concurrent laminar fractures resulted in an auto-decompression of the spinal canal, preserving neurological function.

Mild iron deficiency does not ameliorate the phenotype of a murine erythropoietic protoporphyria model

Reduced ferrochelatase activity in erythropoietic protoporphyria (EPP) causes the accumulation of protoporphyrin IX (PPIX) leading to acute cutaneous photosensitivity and liver injury. Many EPP patients also have a mild hypochromic, microcytic anemia and iron deficiency. Iron deficiency can lead to decreased PPIX accumulation in another erythropoietic porphyria, congenital erythropoietic porphyria (CEP). Expression of the iron regulatory peptide hepcidin is negatively regulated by the serine protease TMPRSS6. Hepcidin induction by siRNA-mediated inhibition of TMPRSS6 expression reduces iron availability and induces iron deficiency. To interrogate the therapeutic potential of iron deficiency to modify EPP, we treated an ethylnitrosourea-induced mouse model of EPP, Fech ^m1Pas , with a GalNAc-conjugated Tmprss6 siRNA and PPIX levels, anemia and iron parameters were monitored. The GalNAc-RNAi therapeutic reduces Tmprss6 expression and induces mild iron deficiency in Fech ^m1Pas animals. However, decreases in erythrocyte PPIX levels and liver PPIX accumulation were not seen. These results indicate short-term induction of iron deficiency, at least in a murine model of EPP, does not lead to decreased PPIX production.

Operative Management of Perinatal Lumbar Disc Herniation and Cauda Equina Syndrome: A Case Series

Introduction Perinatal lumbar discectomy for lumbar disc herniation or cauda equina syndrome is a rare clinical scenario. This case series outlines the surgical management of this clinical scenario at a national tertiary referral centre over a 10-year period Methods A retrospective review of all females who underwent discectomy / decompression for lumbar disc herniation or cauda equina syndrome in the perinatal period at a national tertiary referral centre for spine surgery over a 10-year period between January 2008 to December 2017. Results 6 cases required surgical intervention. All patients were successfully managed with surgical decompressive procedures and recovered well in the postoperative period without complication. Conclusions The principles of management remain the same in the pregnant and non-pregnant populations, although treatment options are complicated by the desire to avoid risk to the developing foetus. Surgical intervention is safe to both mother and baby and if performed promptly is associated with an excellent functional outcome.

RNAi-mediated reduction of hepatic Tmprss6 diminishes anemia and secondary iron overload in a splenectomized mouse model of β-thalassemia intermedia

Diminished β-globin synthesis in β-thalassemia is associated with ineffective erythropoiesis, leading to secondary iron overload caused by inappropriately low levels of hepcidin and to splenomegaly in the symptomatic thalassemias. Splenectomy is often employed in patients with β-thalassemia to reduce hemolysis. Expression of the iron regulatory peptide hormone hepcidin is repressed by the serine protease TMPRSS6. Hepcidin induction by RNAi-mediated inhibition of TMPRSS6 expression reduces iron overload and mitigates anemia in murine models of β-thalassemia intermedia. To interrogate the efficacy of RNAi-mediated reduction of Tmprss6 in splenectomized β-thalassemia, splenectomized β-thalassemic Hbb^th3/+ animals were treated with a GalNAc-conjugated siRNA targeting Tmprss6 (GalNAc-Tmprss6) and their hematological and iron parameters monitored. We demonstrate that treatment with GalNAc-Tmprss6 significantly diminishes Tmprss6 expression and appropriately elevates hepcidin expression in splenectomized Hbb^th3/+ animals. Similar to unsplenectomized animals, treated animals have markedly improved anemia due to diminished ineffective erythropoiesis and reduced iron loading in both serum and tissue. These results suggest that RNAi-mediated reduction of Tmprss6 may have positive outcomes even in splenectomized β-thalassemia patients.

Evaluation of GalNAc-siRNA Conjugate Activity in Pre-clinical Animal Models with Reduced Asialoglycoprotein Receptor Expression

The hepatocyte-specific asialoglycoprotein receptor (ASGPR) is an ideal candidate for targeted drug delivery to the liver due to its high capacity for substrate clearance from circulation together with its well-conserved expression and function across species. The development of GalNAc-siRNA conjugates, in which a synthetic triantennary N-acetylgalactosamine-based ligand is conjugated to chemically modified siRNA, has enabled efficient, ASGPR-mediated delivery to hepatocytes. To investigate the potential impact of variations in receptor expression on the efficiency of GalNAc-siRNA conjugate delivery, we evaluated the pharmacokinetics and pharmacodynamics of GalNAc-siRNA conjugates in multiple pre-clinical models with reduced receptor expression. Despite greater than 50% reduction in ASGPR levels, GalNAc conjugate activity was retained, suggesting that the remaining receptor capacity was sufficient to mediate efficient uptake of potent GalNAc-siRNAs at pharmacologically relevant dose levels. Collectively, our data support a broad application of the GalNAc-siRNA technology for hepatic targeting, including disease states where ASGPR expression may be reduced.

Characterization of Community-Acquired Staphylococcus aureus Infections in Children

Background:

Limited data exist concerning characteristics of community-acquired Staphylococcus aureus infections (CA-SAI) in central and eastern Kentucky.

Objective:

To describe the incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections from January 1, 2004 through December 31, 2005, compare the number of CA-MRSA infections between years, and contrast treatment interventions and antibiotic susceptibility patterns of CA-SAI.

Methods:

A concurrent and retrospective study was conducted in 125 patients less than 18 years of age with CA-SAI admitted to the hospital/clinic based on criteria from the Centers for Disease Control and Prevention. Data on demographics, length of stay, antibiotic therapy, and antibiotic susceptibilities were collected.

Results:

Seventy patients were included for analysis (CA-MRSA, n = 51; community-acquired methicillin-susceptible S. aureus [CA-MSSA], n = 19). No statistically significant differences were noted between the number of CA-MRSA infections and the total CA-SAI (9/15 in 2004 vs 42/55 in 2005; p = 0.15). Approximately 75% of patients with CA-SAI were admitted to the hospital with no significant difference in length of stay. Ninety percent of CA-SAI were skin and soft tissue infections. There was a significant difference between groups with cutaneous abscesses (CA-MRSA, n = 37 vs CA-MSSA, n = 6; p = 0.002). Greater than 95% of all isolates were susceptible to vancomycin and trimethoprim/sulfamethoxazole. Half of CA-MRSA patients received inappropriate antibiotic therapy with β-lactam antibiotics or clindamycin without confirmatory disk diffusion test. Twenty-five (49%) patients with CA-MRSA received surgical debridement (S/D) and/or incision and drainage (I/D) with concomitant antibiotic therapy. Four patients with CA-MRSA were rehospitalized for subsequent infections; all 4 received appropriate antibiotic therapy.

Conclusions:

A noticeable increase in CA-MRSA infections with cutaneous abscess between 2004 and 2005 was noted. In patients receiving inappropriate antibiotic therapy, treatment success was attributed to concomitant S/D and I/D. Further analysis should focus on the impact of antibiotic therapy alone or in combination with S/D and I/D on the incidence of subsequent CA-MRSA infections.

Analysis of Morbidity in Liver Transplant Recipients following Human Albumin Supplementation: A Retrospective Pilot Study

Objectives

To assess incidence of morbidity (ie, documented infection, acute renal failure, acute graft rejection, acute cardiovascular events, and hospital read-mission rates) 6 months following liver transplantation using linear regression as a function of cumulative albumin dose.

Design

Retrospective chart review.

Setting

A 473-bed tertiary care teaching facility with a solid-organ transplantation center.

Patients

Forty liver transplant recipients examined from January 1 to December 31, 2003.

Measurements and Results

Data from 40 liver transplant recipients were collected. Mean albumin dose administered was 190.9 ± 162.3 g. No statistical differences were identified in patients receiving less than 140 g (n = 20) or more than 140 g (n = 20) with respect to demographic data other than gender and ethnicity. The mean APACHE III (Acute Physiology and Chronic Health) score was 69.7 ± 24.3. Approximately 70 episodes of morbidity and 23 readmissions were observed. Regardless of the APACHE III score, albumin was associated with increased overall morbidity and cardiovascular complications. Liver transplant recipients receiving more than 140 g had a longer hospital stay (14 vs 8 days, P = .025) and intensive care unit stay (6 vs 3 days, P = .051) than patients receiving 140 g or less. No correlation with risk of acute rejection was seen with albumin or tacrolimus.

Conclusion

Albumin supplementation among liver transplant recipients was associated with a significant risk for cardiovascular complications and overall number of complications regardless of APACHE III score. Future prospective studies are needed to further define the potential risk for complications in this patient population.

Preclinical evaluation of RNAi as a treatment for transthyretin-mediated amyloidosis

ATTR amyloidosis is a systemic, debilitating and fatal disease caused by transthyretin (TTR) amyloid accumulation. RNA interference (RNAi) is a clinically validated technology that may be a promising approach to the treatment of ATTR amyloidosis. The vast majority of TTR, the soluble precursor of TTR amyloid, is expressed and synthesized in the liver. RNAi technology enables robust hepatic gene silencing, the goal of which would be to reduce systemic levels of TTR and mitigate many of the clinical manifestations of ATTR that arise from hepatic TTR expression. To test this hypothesis, TTR-targeting siRNAs were evaluated in a murine model of hereditary ATTR amyloidosis. RNAi-mediated silencing of hepatic TTR expression inhibited TTR deposition and facilitated regression of existing TTR deposits in pathologically relevant tissues. Further, the extent of deposit regression correlated with the level of RNAi-mediated knockdown. In comparison to the TTR stabilizer, tafamidis, RNAi-mediated TTR knockdown led to greater regression of TTR deposits across a broader range of affected tissues. Together, the data presented herein support the therapeutic hypothesis behind TTR lowering and highlight the potential of RNAi in the treatment of patients afflicted with ATTR amyloidosis.

Post operative complications in a dedicated elective orthopaedic hospital: transfers requiring specialist critical care support

We aim to report our experience with out of hospital transfers for postoperative complications in a stand-alone elective orthopaedic hospital. We aim to describe the cohort of patients transferred, the rate of transfer and assess the risk factors for transfer. Patients were identified who were transferred out of the hospital to another acute hospital for management of non-routine medical problems. Patient data was collected relating to age, BMI, ASA, type of surgery, nature of the complication, timing and the outcome of transfer. In 2012, 2,853 inpatient surgical procedures were carried out, 51 patients (1.8%) developed a postoperative complication that required out of hospital transfer. Mean age of patients transferred was 67 (12-86) years, mean age of the overall case mix 58 years (0-96) (p = 0.01). 37.7% of the overall case mix of surgeries was made up of primary hip and knee arthroplasty procedures, these patients made up 63.7% of patients transferred out (p = 0.001). Mean BMI recorded was 31.7 (22-48) compared to the mean BMI of the total arthroplasty case mix of 28.8 (20-44) (p = 0.02). 59% of all patients at our institution were ASA category II or III. 76% of patients transferred were ASA category II or III (p = 0.005). We can conclude that patients requiring transfer are typically older. Arthroplasty patients are more likely to require transfer than patients undergoing other orthopaedic procedures. Among the arthroplasty cohort transferred patients will typically have a higher BMI than average. Patients with ASA category II or III make up nearly three quarters of those patients transferred. The mean age of patients transferred is typically older by 9 years.

Combination therapy with a Tmprss6 RNAi-therapeutic and the oral iron chelator deferiprone additively diminishes secondary iron overload in a mouse model of β-thalassemia intermedia

β-thalassemias result from diminished β-globin synthesis and are associated with ineffective erythropoiesis and secondary iron overload caused by inappropriately low levels of the iron regulatory hormone hepcidin. The serine protease TMPRSS6 attenuates hepcidin production in response to iron stores. Hepcidin induction reduces iron overload and mitigates anemia in murine models of β-thalassemia intermedia. To further interrogate the efficacy of an RNAi-therapeutic downregulating Tmprss6, β-thalassemic Hbb^th3/+ animals on an iron replete, an iron deficient, or an iron replete diet also containing the iron chelator deferiprone were treated with Tmprss6 siRNA. We demonstrate that the total body iron burden is markedly improved in Hbb^th3/+ animals treated with siRNA and chelated with oral deferiprone, representing a significant improvement compared to either compound alone. These data indicate that siRNA suppression of Tmprss6, in conjunction with oral iron chelation therapy, may prove superior for treatment of anemia and secondary iron loading seen in β-thalassemia intermedia. Am. J. Hematol. 90:310–313, 2015. © 2015 The Authors. American Journal of Hematology Published by Wiley Periodicals, Inc.

A competitive enzyme-linked immunosorbent assay specific for murine hepcidin-1: correlation with hepatic mRNA expression in established and novel models of dysregulated iron homeostasis

Mice have been essential for distinguishing the role of hepcidin in iron homeostasis. Currently, investigators monitor levels of murine hepatic hepcidin-1 mRNA as a surrogate marker for the bioactive hepcidin protein itself. Here, we describe and validate a competitive, enzyme-linked immunosorbent assay that quantifies hepcidin-1 in mouse serum and urine. The assay exhibits a biologically relevant lower limit of detection, high precision, and excellent linearity and recovery. We also demonstrate correlation between serum and urine hepcidin-1 values and validate the competitive enzyme-linked immunosorbent assay by analyzing plasma hepcidin response of mice to physiological challenges, including iron deficiency, iron overload, acute blood loss, and inflammation. Furthermore, we analyze multiple murine genetic models of iron dysregulation, including β-thalassemia intermedia (Hbb(th3/+)), hereditary hemochromatosis (Hfe(-/-), Hjv(-/-), and Tfr2(Y245X/Y245X)), hypotransferrinemia (Trf(hpx/hpx)), heterozygous transferrin receptor 1 deficiency (Tfrc(+/-)) and iron refractory iron deficiency anemia (Tmprss6(-/-) and Tmprss6(hem8/hem8)). Novel compound iron metabolism mutants were also phenotypically characterized here for the first time. We demonstrate that serum hepcidin concentrations correlate with liver hepcidin mRNA expression, transferrin saturation and non-heme liver iron. In some circumstances, serum hepcidin-1 more accurately predicts iron parameters than hepcidin mRNA, and distinguishes smaller, statistically significant differences between experimental groups.

Healthcare Costs Associated With Chronic Opioid Use and Fibromayalgia Syndrome

BACKGROUND

Fibromyalgia (FM) is an idiopathic, functional syndrome characterized by chronic, widespread pain and diffuse tenderness. This disorder affects more than 6 million patients in the United States and is associated with significant clinical and economic burdens.

OBJECTIVES

The objectives of this study were to: 1) estimate the costs associated with a FM diagnosis; and 2) estimate the impact of chronic opioid use on the costs of FM patients.

RESEARCH DESIGN

Case-control study.

METHODS

Subjects were identified in a large nationally representative database of commercially insured patients. Propensity score-matched analyses included 445,912 FM-control pairs in the first analysis, while the second analysis included 48,333 chronic opioid users with the FM-control pairs. Primary outcomes of interest were the medical and prescription costs compared between matched pairs, based on propensity for being a case as evidenced by coefficients obtained from a first-stage logistic regression. Patient characteristics considered include: state of residence, diagnosing provider type, comorbid conditions, and concurrent medication use.

RESULTS

When controlling for propensity to receive a FM diagnosis, the actual diagnosis has a small effect on medical (-$83.54 [95% CI, -152.55 to -16.53]) and prescription ($120.31 [95% CI, 109.98-130.62]) costs. However, the effect of chronic opioid use in FM patients on medical ($9094.05 [95% CI, 8924.79-9263.31]) and prescription ($3391.81 [95% CI, 3368.84-3414.79]) costs is much more substantial.

CONCLUSIONS

While the differences seen in FM patients and controls are marginal, those attributed to chronic opioid use in these patients are significantly higher. Chronic opioid therapy to treat FM is a practice based not on evidence available to practitioners, but on other variables.

Safety and efficacy of RNAi therapy for transthyretin amyloidosis

BACKGROUND

Transthyretin amyloidosis is caused by the deposition of hepatocyte-derived transthyretin amyloid in peripheral nerves and the heart. A therapeutic approach mediated by RNA interference (RNAi) could reduce the production of transthyretin.

METHODS

We identified a potent antitransthyretin small interfering RNA, which was encapsulated in two distinct first- and second-generation formulations of lipid nanoparticles, generating ALN-TTR01 and ALN-TTR02, respectively. Each formulation was studied in a single-dose, placebo-controlled phase 1 trial to assess safety and effect on transthyretin levels. We first evaluated ALN-TTR01 (at doses of 0.01 to 1.0 mg per kilogram of body weight) in 32 patients with transthyretin amyloidosis and then evaluated ALN-TTR02 (at doses of 0.01 to 0.5 mg per kilogram) in 17 healthy volunteers.

RESULTS

Rapid, dose-dependent, and durable lowering of transthyretin levels was observed in the two trials. At a dose of 1.0 mg per kilogram, ALN-TTR01 suppressed transthyretin, with a mean reduction at day 7 of 38%, as compared with placebo (P=0.01); levels of mutant and nonmutant forms of transthyretin were lowered to a similar extent. For ALN-TTR02, the mean reductions in transthyretin levels at doses of 0.15 to 0.3 mg per kilogram ranged from 82.3 to 86.8%, with reductions of 56.6 to 67.1% at 28 days (P<0.001 for all comparisons). These reductions were shown to be RNAi-mediated. Mild-to-moderate infusion-related reactions occurred in 20.8% and 7.7% of participants receiving ALN-TTR01 and ALN-TTR02, respectively.

CONCLUSIONS

ALN-TTR01 and ALN-TTR02 suppressed the production of both mutant and nonmutant forms of transthyretin, establishing proof of concept for RNAi therapy targeting messenger RNA transcribed from a disease-causing gene. (Funded by Alnylam Pharmaceuticals; ClinicalTrials.gov numbers, NCT01148953 and NCT01559077.).

Cortical cross-frequency coupling predicts perceptual outcomes

Functional networks are comprised of neuronal ensembles bound through synchronization across multiple intrinsic oscillatory frequencies. Various coupled interactions between brain oscillators have been described (e.g., phase-amplitude coupling), but with little evidence that these interactions actually influence perceptual sensitivity. Here, electroencephalographic (EEG) recordings were made during a sustained-attention task to demonstrate that cross-frequency coupling has significant consequences for perceptual outcomes (i.e., whether participants detect a near-threshold visual target). The data reveal that phase-detection relationships at higher frequencies are dependent on the phase of lower frequencies, such that higher frequencies alternate between periods when their phase is either strongly or weakly predictive of visual-target detection. Moreover, the specific higher frequencies and scalp topographies linked to visual-target detection also alternate as a function of lower-frequency phase. Cross-frequency coupling between lower (i.e., delta and theta) and higher frequencies (e.g., low- and high-beta) thus results in dramatic fluctuations of visual-target detection.

Do less effective teachers choose professional development does it matter?

BACKGROUND

In an ongoing effort to improve teacher quality, most states require continuing education or professional development for their in-service teachers. Studies evaluating the effectiveness of various professional development programs have assumed a normal distribution of quality of teachers participating in the programs. Because participation in many professional development programs is either targeted or voluntary, this article suggests past evaluations of the effectiveness of professional development may be subject to selection bias and policy recommendations may be premature.

RESEARCH DESIGN

This article presents an empirical framework for evaluating professional development programs where treatment is potentially nonrandom, and explicitly accounts for the teacher's prior effectiveness in the classroom as a factor that may influence participation in professional development. This article controls for the influence of selection bias on professional development outcomes by generating a matched sample based on propensity scores and then estimating the program's effect.

RESULTS

In applying this framework to the professional development program examined in this article, less effective teachers are found to be more likely to participate in the program, and correcting for this selection leads to different conclusions regarding the program's effectiveness than when ignoring teacher selection patterns.

Health-related quality of life and functional outcomes following nerve transfers for traumatic upper brachial plexus injuries

We report the patient-scored Health-Related Quality of Life (HRQoL) and functional outcomes of a cohort of 21 consecutive patients undergoing nerve transfer surgery for traumatic upper brachial plexus injuries. Outcomes were assessed using the British Medical Research Council power grading system, Short-Form 36, Disability of Arm, Shoulder and Hand questionnaire, and Pain Visual Analogue Scale (PVAS). The mean age of our cohort was 29.8 years (range 18-53 years), with a mean follow-up period of 42.9 months. At follow-up, elbow flexion ≥ M3 strength was achieved in 17/21 patients. Shoulder abduction ≥ M3 was achieved in 14/19 patients. External rotation ≥ M3 strength was achieved in 11/15 patients. Delayed surgical repair correlated negatively with HRQoL outcomes. Higher injury severity scores and smoking were associated with higher PVAS scores. These findings provide key prognostic information for patients and peripheral nerve surgeons embarking upon this intensive pathway to potential recovery.

Neural correlates of oddball detection in self-motion heading: a high-density event-related potential study of vestibular integration

The perception of self-motion is a product of the integration of information from both visual and non-visual cues, to which the vestibular system is a central contributor. It is well documented that vestibular dysfunction leads to impaired movement and balance, dizziness and falls, and yet our knowledge of the neuronal processing of vestibular signals remains relatively sparse. In this study, high-density electroencephalographic recordings were deployed to investigate the neural processes associated with vestibular detection of changes in heading. To this end, a self-motion oddball paradigm was designed. Participants were translated linearly 7.8 cm on a motion platform using a one second motion profile, at a 45° angle leftward or rightward of straight ahead. These headings were presented with a stimulus probability of 80-20 %. Participants responded when they detected the infrequent direction change via button-press. Event-related potentials (ERPs) were calculated in response to the standard (80 %) and target (20 %) movement directions. Statistical parametric mapping showed that ERPs to standard and target movements differed significantly from 490 to 950 ms post-stimulus. Topographic analysis showed that this difference had a typical P3 topography. Individual participant bootstrap analysis revealed that 93.3 % of participants exhibited a clear P3 component. These results indicate that a perceived change in vestibular heading can readily elicit a P3 response, wholly similar to that evoked by oddball stimuli presented in other sensory modalities. This vestibular-evoked P3 response may provide a readily and robustly detectable objective measure for the evaluation of vestibular integrity in various disease models.

Health-related quality of life, surgical and aesthetic outcomes following microvascular free flap reconstructions: an 8-year institutional review

INTRODUCTION

Microvascular free flap reconstruction has revolutionised the reconstruction of complex defects of traumatic, oncological, congenital and infectious aetiologies. Complications of microvascular free flap procedures impact negatively on patient post-operative course and outcome.

METHODS

We performed a retrospective analysis of 102 consecutive patients undergoing 108 free flap procedures at a tertiary referral centre over an 8-year period. Logistic regression analysis was used to identify factors predictive of free flap complications. Health-related quality of life (HRQoL) and aesthetic outcomes were assessed using the Short Form 36 questionnaire and a satisfaction visual analogue scale respectively.

RESULTS

In total, 108 free tissue transfers were performed; 23% were fasciocutaneous free flaps, 69% musculocutaneous and 8% osteoseptocutaneous. The overall flap success rate was 92.6%. Over a third of patients (34.3%) had flap-related complications ranging from minor wound dehiscence to total flap loss. ASA (American Society of Anesthesiologists) grade ≥2 (OR: 16.9, 95% CI: 15.3-18.1, p<0.009), history of smoking (OR: 6.1, 95% CI: 5.5-7.2, p<0.049), body mass index ≥25 kg/m(2) (OR: 21.3, 95% CI: 20.8-22.1, p<0.003), low albumin (odds ratio [OR]: 2.2, 95% confidence interval [CI]: 1.2-3.9, p<0.003) and peripheral vascular disease (OR: 6.9, 95% CI: 5.9-7.5, p<0.036) were identified as factors independently predictive of free flap complications.

CONCLUSIONS

Patients undergoing uncomplicated free flap surgery and those reporting superior post-operative flap aesthesis have higher HRQoL scores. Microvascular free tissue transfer has revolutionised our approach to the reconstruction of complex defects, providing a safe, reliable procedure to restore functionality and quality of life for patients.

Patient interpretations of prescription order quantitative statements

OBJECTIVES

To characterize the variability in patient understanding and interpretation of quantitative statements from prescription orders and to evaluate the influence of sociodemographic characteristics on how patients interpret quantitative statements.

METHODS

Participants were recruited in both a clinic and pharmacy setting in Kentucky. Patients were given a survey that asked for general background information and two questions pertaining to their experience with topical products. Then, patients were read a scenario and asked to use a provided tube of cream and squeeze out what they considered a small amount.

RESULTS

100 eligible patients participated in the study, with the majority having previous counseling on the use of topical products. The mean (±SD) cream weight representing a small amount was 0.36 ± 0.50 g. Regression analysis demonstrated a significant nonlinear relationship for two of the patient characteristics, age and body mass index (BMI), with the greatest effect in the middle of age and BMI distributions (at approximately age 50 years and BMI 30 kg/m²). No evidence indicated that gender, race, education, or previous experience with or education about topical products had any effect on cream weight perception.

CONCLUSION

Patients demonstrated tremendous variability in the interpretation of a small amount of topical product cream. Further research should be conducted to determine whether policy changes are warranted to require more specific prescription order instructions in the outpatient setting.

Using linked household-level data sets to explain consumer response to bovine spongiform encepalopathy (BSE) in Canada

Household-level Canadian meat purchases from 2002 to 2008 and a Food Opinions Survey conducted in 2008 were used to explore consumer responses to bovine spongiform encephalopathy (BSE) at the national level in Canada. Consumption in terms of the number of unit purchases was analyzed with a random-effects negative binomial model. In this study, household heterogeneity in meat purchases was partially explained using data from a self-reported food opinions survey. Of special interest was the hypothesis that consumers responded consistently to BSE in a one-time survey and in actual meat purchase behavior spanning years. Regional differences appeared, with consumers in eastern Canada reacting most negatively to BSE. Consumers responded more to the perception that food decision makers are honest about food safety than to the perception that they are knowledgeable, in maintaining beef purchases during BSE events.

H1N1 infection in emergency surgery: A cautionary tale

Pandemic 2009 influenza A H1N1 has spread rapidly since its first report in Mexico in March 2009. This is the first influenza pandemic in over 40 years and it atypically affects previously healthy young adults, with higher rates of morbidity and mortality. The medical literature has been inundated with reports of H1N1 infection, the majority found in critical care and internal medicine journals with a relative paucity in the surgical literature. Despite this, it remains an important entity that can impact greatly on acute surgical emergencies. We present a case of previously healthy 31-year-old male who underwent open appendectomy. His post-operative recovery was complicated by acute respiratory distress syndrome secondary to H1N1 infection. This case report highlights the impact that H1N1 virus can have on acute surgical emergencies and how it can complicate the post-operative course.

Targeted delivery of RNAi therapeutics with endogenous and exogenous ligand-based mechanisms

Lipid nanoparticles (LNPs) have proven to be highly efficient carriers of short-interfering RNAs (siRNAs) to hepatocytes in vivo; however, the precise mechanism by which this efficient delivery occurs has yet to be elucidated. We found that apolipoprotein E (apoE), which plays a major role in the clearance and hepatocellular uptake of physiological lipoproteins, also acts as an endogenous targeting ligand for ionizable LNPs (iLNPs), but not cationic LNPs (cLNPs). The role of apoE was investigated using both in vitro studies employing recombinant apoE and in vivo studies in wild-type and apoE(-/-) mice. Receptor dependence was explored in vitro and in vivo using low-density lipoprotein receptor (LDLR(-/-))-deficient mice. As an alternative to endogenous apoE-based targeting, we developed a targeting approach using an exogenous ligand containing a multivalent N-acetylgalactosamine (GalNAc)-cluster, which binds with high affinity to the asialoglycoprotein receptor (ASGPR) expressed on hepatocytes. Both apoE-based endogenous and GalNAc-based exogenous targeting appear to be highly effective strategies for the delivery of iLNPs to liver.

The long-term functional outcome of type II odontoid fractures managed non-operatively

Odontoid fractures currently account for 9-15% of all adult cervical spine fractures, with type II fractures accounting for the majority of these injuries. Despite recent advances in internal fixation techniques, the management of type II fractures still remains controversial with advocates still supporting non-rigid immobilization as the definitive treatment of these injuries. At the NSIU, over an 11-year period between 1 July 1996 and 30 June 2006, 66 patients (n = 66) were treated by external immobilization for type II odontoid fractures. The medical records, radiographs and CT scans of all patients identified were reviewed. Clinical follow-up evaluation was performed using the Cervical Spine Outcomes Questionnaire (CSOQ). The objectives of this study were to evaluate the long-term functional outcome of patients suffering isolated type II odontoid fractures managed non-operatively and to correlate patient age and device type with clinical and functional outcome. Of the 66 patients, there were 42 males and 24 females (M:F = 1.75:1) managed non-operatively for type II odontoid fractures. The mean follow-up time was 66 months. Advancing age was highly correlated with poorer long-term functional outcomes when assessing neck pain (r = 0.19, P = 0.1219), shoulder and arm pain (r = 0.41, P = 0.0007), physical symptoms (r = 0.25, P = 0.472), functional disability (r = 0.24, P = 0.0476) and psychological distress (r = 0.41, P = 0.0007). Patients >65 years displayed a higher rate of pseudoarthrosis (21.43 vs. 1.92%) and established non-union (7.14 vs. 0%) than patients <65 years. The non-operative management of type II odontoid fractures is an effective and satisfactory method of treating type II odontoid fractures, particularly those of a stable nature. However, patients of advancing age have been demonstrated to have significantly poorer functional outcomes in the long term. This may be linked to higher rates of non-union.

Folding of tetrameric p53: oligomerization and tumorigenic mutations induce misfolding and loss of function

The physiologically active form of p53 consists of a tetramer of four identical 393-amino-acid subunits associated via their tetramerization domains (TDs; residues 325-355). One in two human tumors contains a point mutation in the DNA binding domain (DBD) of p53 (residues 94-312). Most existing studies on the effects of these mutations on p53 structure and function have been carried out on the isolated DBD fragment, which is monomeric. Recent structural evidence, however, suggests that DBDs may interact with each other in full-length tetrameric forms of p53. Here, we investigate the effects of tumorigenic DBD mutations on the folding of p53 in its tetrameric form. We employ the construct consisting of DBD and TD (amino acids 94-360). We characterize the stability and conformational state of the tumorigenic DBD mutants R248Q, R249S, and R282Q using equilibrium denaturation and functional assays. Destabilizing mutations cause DBD to misfold when it is part of the p53 tetramer, but not when it is monomeric. This conformation is populated under moderately destabilizing conditions (10 degrees C in 2 M urea, and at physiological temperature in the absence of denaturant). Under those same conditions, it is not present in the isolated DBD fragment or in the presence of the TD mutation L344P, which abolishes tetramerization. Misfolding appears to involve intramolecular DBD-DBD association within a single tetrameric molecule. This association is promoted by destabilization of DBD (caused by mutation or elevated temperature) and by the high local DBD concentration enforced by tetramerization of TD. Disrupting the nonnative DBD-DBD interaction or transiently inhibiting tetramerization and allowing p53 to fold as a monomer may be potential strategies for pharmacological intervention in cancer.

Cobalt ions induce chemokine secretion in primary human osteoblasts

Chemokines are major regulators of the inflammatory response and have been shown to play an important role in periprosthetic osteolysis. Titanium particles have previously been shown to induce IL-8 and MCP-1 secretion in osteoblasts. These chemokines result in the chemotaxis and activation of neutrophils and macrophages, respectively. Despite a resurgence in the use of cobalt-chromium-molybdenum alloys in metal-on-metal arthroplasty, cobalt and chromium ion toxicity in the periprosthetic area has been insufficiently studied. In this study we investigate the in vitro effect of cobalt ions on primary human osteoblast activity. We demonstrate that cobalt ions rapidly induce the protein secretion of IL-8 and MCP-1 in primary human osteoblasts. This elevated chemokine secretion is preceded by an increase in the transcription of the corresponding chemokine gene. Using a Transwell migration chemotaxis assay we also demonstrate that the chemokines secreted are capable of inducing neutrophil and macrophage migration. Furthermore, cobalt ions significantly inhibit osteoblast function as demonstrated by reduced alkaline phosphatase activity and calcium deposition. In aggregate these data demonstrate that cobalt ions can activate transcription of the chemokine genes IL-8 and MCP-1 in primary human osteoblasts. Cobalt ions are not benign and may play an important role in the pathogenesis of osteolysis by suppressing osteoblast function and stimulating the production and secretion of chemokines that attract inflammatory and osteoclastic cells to the periprosthetic area.

Structural and thermodynamic analysis of a conformationally strained circular permutant of barnase

Circular permutation of a protein covalently links its original termini and creates new ends at another location. To maintain the stability of the permuted structure, the termini are typically bridged by a peptide long enough to span the original distance between them. Here, we take the opposite approach and employ a very short linker to introduce conformational strain into a protein by forcing its termini together. We join the N- and C-termini of the small ribonuclease barnase (normally 27.2 A distant) with a single Cys residue and introduce new termini at a surface loop, to create pBn. Compared to a similar variant permuted with an 18-residue linker, permutation with a single amino acid dramatically destabilizes barnase. Surprisingly, pBn is folded at 10 degrees C and possesses near wild-type ribonuclease activity. The 2.25 A X-ray crystal structure of pBn reveals how the barnase fold is able to adapt to permutation, partially defuse conformational strain, and preserve enzymatic function. We demonstrate that strain in pBn can be relieved by cleaving the linker with a chemical reagent. Catalytic activity of both uncleaved (strained) pBn and cleaved (relaxed) pBn is proportional to their thermodynamic stabilities, i.e., the fraction of folded molecules. The stability and activity of cleaved pBn are dependent on protein concentration. At concentrations above approximately 2 microM, cleaving pBn is predicted to increase the fraction of folded molecules and thus enhance ribonuclease activity at 37 degrees C. This study suggests that introducing conformational strain by permutation, and releasing strain by cleavage, is a potential mechanism for engineering an artificial zymogen.

The increased need for liaison psychiatry in surgical patients due to the high prevalence of undiagnosed anxiety and depression

BACKGROUND

Depression is the most common mental disease in patients hospitalized with physical illness. Disorders of anxiety and depression in general hospitals are frequently underdiagnosed and inappropriately treated.

AIM

To assess the prevalence of undiagnosed anxiety and depression in surgical inpatients and assess the referral rate and utilization of liaison psychiatry services.

METHODS

A prospective study of surgical admissions (n = 96) to two surgical services at two separate institutions between 01/01/05 and 31/12/05. The Hospital Anxiety and Depression (HADS) scale was used to evaluate all patients.

RESULTS

About 12.5% of patients had significant depression, 18.75% had significant anxiety, and 8.3% had significant mixed anxiety and depression. About 22.9% of patients warranted referral to liaison psychiatry services for further assessment and management.

CONCLUSIONS

Anxiety and depression are highly prevalent in surgical inpatients. An increased awareness of the possibility of undiagnosed psychiatric disorders is required, along with prompt and appropriate use of liaison psychiatry services.

Dynamics of equilibrium structural fluctuations of apomyoglobin measured by fluorescence correlation spectroscopy

The spectra of equilibrium chain conformation fluctuations of apomyoglobin (apoMb) as a function of folding, from the acid-denatured state at pH 2.6 through the stable molten globule state pH approximately 4.1 to the folded state at pH 6.3, are reported, as measured by fluorescence correlation spectroscopy. The conformational fluctuations, which are detected by quenching of an N-terminal fluorescent label by contact with various amino acids, can be represented by superpositions of decaying exponentials with time scales ranging from approximately 3 to approximately 200 micros. Both the time scales and amplitudes of the fluctuations increase with the degree of acid denaturation, with principal shifts associated with the transition across the molten globule state. Measurements of the diffusion of apoMb confirm theoretical values showing a approximately 40% increase in the hydrodynamic radius upon acid denaturation. This study uses the model protein apoMb to illustrate the complex scope of folding associated structural dynamics.

Zn2+-Dependent Misfolding of the p53 DNA Binding Domain

The DNA binding domain (DBD) of p53 folds by a complex mechanism that involves parallel pathways and multiple intermediates, both on- and off-pathway. This heterogeneity renders DBD particularly susceptible to misfolding and aggregation. The origins of parallel folding mechanisms are not well understood. DBD folding heterogeneity may be caused by the presence of the single bound Zn2+. To test that hypothesis, we carried out kinetic folding studies of DBD in its Zn2+-free form (apoDBD) and in the presence of various concentrations of free Zn2+ and the Zn2+-nitrilotriacetate (NTA) complex. Folding kinetics of apoDBD and DBD are similar, although apoDBD folds faster than DBD at some urea concentrations. The principle consequence of Zn2+ removal is to accelerate unfolding and simplify it from two exponential phases to one. Metal binding interactions are therefore not responsible for the observed complexity of the folding reaction. A slight stoichiometric excess of free Zn2+ arrests folding and traps the protein in a misfolded state in which Zn2+ is bound to nonphysiological ligands. Folding can be rescued by providing metal ions in the form of the NTA-Zn2+ complex, which simultaneously protects against misligation and provides a source of Zn2+ for regenerating the functional protein. This chemical metallochaperone strategy may be an effective means for improving folding efficiency of other metal binding proteins. The findings suggest that, in vivo, DBD must fold in an environment where free Zn2+ concentration is low and its bioavailability is carefully regulated by cellular metallochaperones.

Folding and misfolding mechanisms of the p53 DNA binding domain at physiological temperature

p53 modulates a large number of cellular response pathways and is critical for the prevention of cancer. Wild-type p53, as well as tumorigenic mutants, exhibits the singular property of spontaneously losing DNA binding activity at 37 degrees C. To understand the molecular basis for this effect, we examine the folding mechanism of the p53 DNA binding domain (DBD) at elevated temperatures. Folding kinetics do not change appreciably from 5 degrees C to 35 degrees C. DBD therefore folds by the same two-channel mechanism at physiological temperature as it does at 10 degrees C. Unfolding rates, however, accelerate by 10,000-fold. Elevated temperatures thus dramatically increase the frequency of cycling between folded and unfolded states. The results suggest that function is lost because a fraction of molecules become trapped in misfolded conformations with each folding-unfolding cycle. In addition, at 37 degrees C, the equilibrium stabilities of the off-pathway species are predicted to rival that of the native state, particularly in the case of destabilized mutants. We propose that it is the presence of these misfolded species, which can aggregate in vitro and may be degraded in the cell, that leads to p53 inactivation.

Spinal injuries in Irish rugby: a ten-year review

This study assessed the frequency of acute injury to the spinal cord in Irish Rugby over a period of ten years, between 1995 and 2004. There were 12 such injuries; 11 were cervical and one was thoracic. Ten occurred in adults and two in schoolboys. All were males playing Rugby Union and the mean age at injury was 21.6 years (16 to 36). The most common mechanism of injury was hyperflexion of the cervical spine and the players injured most frequently were playing at full back, hooker or on the wing. Most injuries were sustained during the tackle phase of play. Six players felt their injury was preventable. Eight are permanently disabled as a result of their injury.

Trends in RTA related spinal injuries: the post penalty points era

BACKGROUND

On October 31st 2002 a system of cumulative penalty points for road traffic offences was introduced. Early evidence suggested a reduction in road traffic accident (RTA) related morbidity.

AIMS

To evaluate the persistence of the initial reduction in RTA related spinal injuries following penalty points introduction.

METHODS

Retrospective review of all acute spinal trauma admissions to the NSIU between November 1st 1998 and October 31st 2004 (n = 966). Patient demographics and injury aetiology were assessed. Follow-up questionnaires evaluated RTA circumstances.

RESULTS

RTA related spinal injuries accounted for 39.3% of NSIU admissions. These injuries were significantly more common in males aged 16-24, drivers (70.8%), on routine journeys (77.5%) and rural roads (48.8%). The highest proportion of accidents occurred during weekends (64.3% from Fri-Sun) and from midnight to 6am (29.3%).

CONCLUSIONS

The initial reduction in RTA related spinal injuries has not been sustained. Young male drivers are the greatest at risk group.

Modular enzyme design: regulation by mutually exclusive protein folding

A regulatory mechanism is introduced whereupon the catalytic activity of a given enzyme is controlled by ligand binding to a receptor domain of choice. A small enzyme (barnase) and a ligand-binding polypeptide (GCN4) are fused so that a simple topological constraint prevents them from existing simultaneously in their folded states. The two domains consequently engage in a thermodynamic tug-of-war in which the more stable domain forces the less stable domain to unfold. In the absence of ligand, the barnase domain is more stable and is therefore folded and active; the GCN4 domain is substantially unstructured. DNA binding induces folding of GCN4, forcibly unfolding and inactivating the barnase domain. Barnase-GCN4 is thus a "natively unfolded" protein that uses ligand binding to switch between partially folded forms. The key characteristics of each parent protein (catalytic efficiency of barnase, DNA binding affinity and sequence specificity of GCN4) are retained in the chimera. Barnase-GCN4 thus defines a modular approach for assembling enzymes with novel sensor capabilities from a variety of catalytic and ligand binding domains.

Kinetic partitioning during folding of the p53 DNA binding domain

The DNA-binding domain (DBD) of wild-type p53 loses DNA binding activity spontaneously at 37 degrees C in vitro, despite being thermodynamically stable at this temperature. We test the hypothesis that this property is due to kinetic misfolding of DBD. Interrupted folding experiments and chevron analysis show that native molecules are formed via four tracks (a-d) under strongly native conditions. Folding half-lives of tracks a-d are 7.8 seconds, 50 seconds, 5.3 minutes and more than five hours, respectively, in 0.3M urea (10 degrees C). Approximately equal fractions of molecules fold through each track in zero denaturant, but above 2.0M urea approximately 90% fold via track c. A kinetic mechanism consisting of two parallel folding channels (fast and slow) is proposed. Each channel populates an on-pathway intermediate that can misfold to form an aggregation-prone, dead-end species. Track a represents direct folding through the fast channel. Track b proceeds through the fast channel but via the off-pathway state. Track c corresponds to folding via the slow channel, primarily through the off-pathway state. Track d proceeds by way of an even slower, uncharacterized route. We postulate that activity loss is caused by partitioning to the slower tracks, and that structural unfolding limits this process. In support of this view, tumorigenic hot-spot mutants G245S, R249S and R282Q accelerate unfolding rates but have no affect on folding kinetics. We suggest that these and other destabilizing mutants facilitate loss of p53 function by causing DBD to cycle unusually rapidly between folded and unfolded states. A significant fraction of DBD molecules become effectively trapped in a non-functional state with each unfolding-folding cycle.

Factors Leading Patients to Discontinue Multiple Sclerosis Therapies

OBJECTIVES

To determine the percentages of patients who discontinued treatment with the multiple sclerosis medications intramuscular interferon beta-1a (IFN-beta-1a; Avonex-Biogen), interferon beta-1b (IFN-beta-1b; Betaseron-Berlex), and glatiramer acetate (Copaxone-Teva) and to determine the factors that led to discontinuation of the medications.

DESIGN

Cross-sectional study.

SETTING

University-based neurology clinic.

PATIENTS

108 patients with multiple sclerosis who were prescribed intramuscular interferon beta-1a, subcutaneous interferon beta-1b, or subcutaneous glatiramer acetate.

INTERVENTION

Telephone survey.

MAIN OUTCOME MEASURES

Discontinuation percentages and the factors that contributed to discontinuation.

RESULTS

There was no significant difference between the percentages of patients who discontinued and did not restart treatment with the products (interferon beta-1b, 41%; intramuscular interferon beta-1a, 34%; and glatiramer acetate, 28%). Four main reasons for medication discontinuation emerged: adverse effects (52%), physician-documented disease progression (40%), patient perception of drug ineffectiveness (20%), and cost (4%). No statistical differences were identified among the three agents for any of the reasons for discontinuation.

CONCLUSION

Patient education on adverse effects and realistic patient expectations may be potential areas of study to improve discontinuation percentages with these agents.

Bacteriophage P22 Tail Accessory Factor GP26 Is a Long Triple-stranded Coiled-coil

P22 is a well characterized tailed bacteriophage that infects Salmonella enterica serovar Typhimurium. It is characterized by a "short" tail, which is formed by five proteins: the dodecameric portal protein (gp1), three tail accessory factors (gp4, gp10, gp26), and six trimeric copies of the tail-spike protein (gp9). We have isolated the gene encoding tail accessory factor gp26, which is responsible for stabilization of viral DNA within the mature phage, and using a variety of biochemical and biophysical techniques we show that gp26 is very likely a triple stranded coiled-coil protein. Electron microscopic examination of purified gp26 indicates that the protein adopts a rod-like structure approximately 210 angstroms in length. This trimeric rod displays an exceedingly high intrinsic thermostability (T(m) approximately 85 degrees C), which suggests a potentially important structural role within the phage tail apparatus. We propose that gp26 forms the thin needle-like fiber emanating from the base of the P22 neck that has been observed by electron microscopy of negatively stained P22 virions. By analogy with viral trimeric coiled-coil class I membrane fusion proteins, gp26 may represent the membrane-penetrating device used by the phage to pierce the host outer membrane.

Functional outcome of burst fractures of the first lumbar vertebra managed surgically and conservatively

We retrospectively reviewed 31 neurologically intact patients with burst L1 fractures. We obtained a follow-up clinical evaluation after a mean of 43 (14-80) months from 26 patients--11 treated surgically and 15 managed non-surgically. Patients were assessed with regard to pain, employment status, recreational activities and overall satisfaction. At final follow-up of 15 patients managed non-surgically, six had little or no pain; 12 had returned to work with six declaring little or no restrictions, and eight had returned to the same level of recreational activity as prior to injury with seven declaring little or no restrictions. Of 11 patients treated surgically, four had little or no pain; seven had returned to work with three declaring little or no restrictions, three had returned to the same level of recreational activity as prior to injury and four declared little or no restrictions. There was no correlation found between vertebral collapse, kyphosis, retropulsion and clinical outcome. Patients who had non-operative management reported a good functional outcome. However, patients who required surgical stabilisation due to different fracture characteristics reported a poorer functional outcome.