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.