333 Management of Distal Radius Fractures During The COVID-19 Crisis

Introduction

Distal radius fractures are common. Treatment depends on a multitude of factors including the pattern / displacement of the fracture, patient age, pre-morbid function, and surgeon preference. We aim to investigate the effect of the pandemic on the management and short-term outcomes of patients with DRF’s.

Method

Retrospective review of all adult DRF’s two months before and after BOA released emergency standards on trauma management. The primary outcome measure was the proportion of patients managed non-operatively before and during COVID-19. Data extracted: demographics, comorbidities, cognitive baseline, treatment, and follow-up. Radiographs were reviewed for displacement [dorsal tilt (>10^o), ulnar variance (>3mm), intra-articular step (>2mm)].

Results

Pre-COVID (n = 29), COVID (n = 35). Characteristics were comparable in terms of median age (66 and 72 years, p = 0.41), %aged ≤65 (48% and 37%, p = 0.37), dominant side fracture (36% and 40%, p = 0.52), presence ≥ 2 co-morbidities (41% and 43%, p = 0.91). More patients were managed non-operatively during COVID (86% vs. 69%, p = 0.11), 2 of whom had unstable fracture pattern and developed malunion, compared to none in pre-COVID period.

Conclusions

Management of DRF’s remains a controversial topic, particularly in age <65 years. Long term follow up of patients with significant fracture displacement managed conservatively during COVID pandemic could help guide future practice.

A critical analysis of the COMPASS trial with respect to benefit-risk assessment using the numbers needed to treat: Applicability and relevance in Indian patients with stable cardiovascular disease

The recently published Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) trial evaluated the hypothesis that rivaroxaban alone or in combination with aspirin would be more effective than aspirin alone for secondary prevention. In India, stable cardiovascular disease occurs in a much younger age group relative to the rest of the world. Our critical analysis of COMPASS trial showed that the younger age group appeared to derive greater benefit from the rivaroxaban+aspirin combination (relative to aspirin alone) as seen with number needed to treat metrics as compared to the older age group.

Measurement of the ν μ energy spectrum with IceCube-79: IceCube Collaboration

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The ν μ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E ν -range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9 σ in four adjacent bins for neutrino energies E ν ≥ 177.8 TeV . The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.

Plasmablastic lymphoma in HIV patients: Experience at a tertiary care hospital in eastern India

BACKGROUND

Plasmablastic lymphoma (PBL), a rare non-Hodgkin's lymphoma (NHL) variant specifically associated with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), expresses well-differentiated plasma cell markers like CD138, bright CD38, and MUM1; but not conventional B-cell markers. It occurs at unusual sites like oral cavity and orbit, and has poor survival rates.

AIMS

This study serves as a review of a clinical experience with six HIV patients with PBL and observes the spectrum of clinical presentations, histopathologies, and 1-year outcomes in PBL patients.

MATERIALS AND METHODS

This review of six PBL patients was conducted at a tertiary care hospital in eastern India using relevant radiological, histopathogical, and immunohistological studies.

RESULTS

Incidence of PBL among HIV patients was 0.58% (6/1,028). Mean CD4 count at presentation was 125.5 ± 71.1 cells/μL. Sites of involvement included pleura, lung parenchyma, suprarenal gland, pelvic cavity, and retroorbital space (one each). Immunohistopathology of biopsied sample in each patient revealed PBL (positive plasma cell markers MUM-1/IRF4, CD38, and CD138/syndecan; and negative of B-cell markers CD3, CD20, and CD30). Three (60%) were positive for Epstein Barr virus (EBV) immunoglobulin G (IgG). Five surviving patients received CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) regimen and attained partial remission (PR) after six cycles. Subsequently, three patients were started on EPOCH (etoposide, cyclophosphamide, doxorubicin, vincristine, prednisone) therapy; two attained near total regression after 6 months (four cycles). Overall, four patients remained alive with good quality of life at the end of 1 year of follow-up.

CONCLUSION

PBL in HIV occurs at unusual sites with varying aggressivity. This study is too small to comment on the long-term outcomes of PBL in HIV; however, coadministration of antiretroviral therapy (ART) with standard chemotherapy may improve survival.

Constraints on Ultrahigh-Energy Cosmic-Ray Sources from a Search for Neutrinos above 10 PeV with IceCube

We report constraints on the sources of ultrahigh-energy cosmic rays (UHECRs) above 10^{9}  GeV, based on an analysis of seven years of IceCube data. This analysis efficiently selects very high- energy neutrino-induced events which have deposited energies from 5×10^{5}  GeV to above 10^{11}  GeV. Two neutrino-induced events with an estimated deposited energy of (2.6±0.3)×10^{6}  GeV, the highest neutrino energy observed so far, and (7.7±2.0)×10^{5}  GeV were detected. The atmospheric background-only hypothesis of detecting these events is rejected at 3.6σ. The hypothesis that the observed events are of cosmogenic origin is also rejected at >99% CL because of the limited deposited energy and the nonobservation of events at higher energy, while their observation is consistent with an astrophysical origin. Our limits on cosmogenic neutrino fluxes disfavor the UHECR sources having a cosmological evolution stronger than the star formation rate, e.g., active galactic nuclei and γ-ray bursts, assuming proton-dominated UHECRs. Constraints on UHECR sources including mixed and heavy UHECR compositions are obtained for models of neutrino production within UHECR sources. Our limit disfavors a significant part of parameter space for active galactic nuclei and new-born pulsar models. These limits on the ultrahigh-energy neutrino flux models are the most stringent to date.

Searches for Sterile Neutrinos with the IceCube Detector

The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous ν_{μ} or ν[over ¯]_{μ} disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3+1 model, in which muon antineutrinos experience a strong Mikheyev-Smirnov-Wolfenstein-resonant oscillation. The exclusion limits extend to sin^{2}2θ_{24}≤0.02 at Δm^{2}∼0.3  eV^{2} at the 90% confidence level. The allowed region from global analysis of appearance experiments, including LSND and MiniBooNE, is excluded at approximately the 99% confidence level for the global best-fit value of |U_{e4}|^{2}.

Spectrometry of the Earth using Neutrino Oscillations

The unknown constituents of the interior of our home planet have provoked the human imagination and driven scientific exploration. We herein demonstrate that large neutrino detectors could be used in the near future to significantly improve our understanding of the Earth’s inner chemical composition. Neutrinos, which are naturally produced in the atmosphere, traverse the Earth and undergo oscillations that depend on the Earth’s electron density. The Earth’s chemical composition can be determined by combining observations from large neutrino detectors with seismic measurements of the Earth’s matter density. We present a method that will allow us to perform a measurement that can distinguish between composition models of the outer core. We show that the next-generation large-volume neutrino detectors can provide sufficient sensitivity to reject extreme cases of outer core composition. In the future, dedicated instruments could be capable of distinguishing between specific Earth composition models and thereby reshape our understanding of the inner Earth in previously unimagined ways.

Evidence for Astrophysical Muon Neutrinos from the Northern Sky with IceCube

Results from the IceCube Neutrino Observatory have recently provided compelling evidence for the existence of a high energy astrophysical neutrino flux utilizing a dominantly Southern Hemisphere data set consisting primarily of ν(e) and ν(τ) charged-current and neutral-current (cascade) neutrino interactions. In the analysis presented here, a data sample of approximately 35,000 muon neutrinos from the Northern sky is extracted from data taken during 659.5 days of live time recorded between May 2010 and May 2012. While this sample is composed primarily of neutrinos produced by cosmic ray interactions in Earth's atmosphere, the highest energy events are inconsistent with a hypothesis of solely terrestrial origin at 3.7σ significance. These neutrinos can, however, be explained by an astrophysical flux per neutrino flavor at a level of Φ(E(ν))=9.9(-3.4)(+3.9)×10(-19)  GeV(-1) cm(-2) sr(-1) s(-1)(E(ν)/100  TeV(-2), consistent with IceCube's Southern-Hemisphere-dominated result. Additionally, a fit for an astrophysical flux with an arbitrary spectral index is performed. We find a spectral index of 2.2(-0.2)(+0.2), which is also in good agreement with the Southern Hemisphere result.

Management of infected nonunion of the long bones by a multidisciplinary team

Infected nonunion of a long bone continues to present difficulties in management. In addition to treating the infection, it is necessary to establish bony stability, encourage fracture union and reconstruct the soft-tissue envelope. We present a series of 67 infected nonunions of a long bone in 66 patients treated in a multidisciplinary unit. The operative treatment of patients suitable for limb salvage was performed as a single procedure. Antibiotic regimes were determined by the results of microbiological culture. At a mean follow-up of 52 months (22 to 97), 59 patients (88%) had an infection-free united fracture in a functioning limb. Seven others required amputation (three as primary treatment, three after late failure of limb salvage and one for recalcitrant pain after union). The initial operation achieved union in 54 (84%) of the salvaged limbs at a mean of nine months (three to 26), with recurrence of infection in 9%. Further surgery in those limbs that remained ununited increased the union rate to 62 (97%) of the 64 limbs treated by limb salvage at final follow-up. The use of internal fixation was associated with a higher risk of recurrent infection than external fixation.

Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube

A diffuse flux of astrophysical neutrinos above 100 TeV has been observed at the IceCube Neutrino Observatory. Here we extend this analysis to probe the astrophysical flux down to 35 TeV and analyze its flavor composition by classifying events as showers or tracks. Taking advantage of lower atmospheric backgrounds for showerlike events, we obtain a shower-biased sample containing 129 showers and 8 tracks collected in three years from 2010 to 2013. We demonstrate consistency with the (fe:fμ:fτ)⊕≈(1:1:1)⊕ flavor ratio at Earth commonly expected from the averaged oscillations of neutrinos produced by pion decay in distant astrophysical sources. Limits are placed on nonstandard flavor compositions that cannot be produced by averaged neutrino oscillations but could arise in exotic physics scenarios. A maximally tracklike composition of (0:1:0)⊕ is excluded at 3.3σ, and a purely showerlike composition of (1:0:0)⊕ is excluded at 2.3σ.

Development of a general analysis and unfolding scheme and its application to measure the energy spectrum of atmospheric neutrinos with IceCube: IceCube Collaboration

We present the development and application of a generic analysis scheme for the measurement of neutrino spectra with the IceCube detector. This scheme is based on regularized unfolding, preceded by an event selection which uses a Minimum Redundancy Maximum Relevance algorithm to select the relevant variables and a random forest for the classification of events. The analysis has been developed using IceCube data from the 59-string configuration of the detector. 27,771 neutrino candidates were detected in 346 days of livetime. A rejection of 99.9999 % of the atmospheric muon background is achieved. The energy spectrum of the atmospheric neutrino flux is obtained using the TRUEE unfolding program. The unfolded spectrum of atmospheric muon neutrinos covers an energy range from 100 GeV to 1 PeV. Compared to the previous measurement using the detector in the 40-string configuration, the analysis presented here, extends the upper end of the atmospheric neutrino spectrum by more than a factor of two, reaching an energy region that has not been previously accessed by spectral measurements.

Observation of high-energy astrophysical neutrinos in three years of IceCube data

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8)  GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

Patient-reported outcomes following treatment of tibial non-union with circular frames

The management of tibial non-union is challenging with protracted, often arduous, treatments. The purpose of this study was to assess patient-reported outcomes following treatment of tibial non-union in circular external fixators. Twenty-one patients with tibial non-unions who successfully completed treatment at a mean of 10.1 months (range 6–20) in a circular external fixator were sent questionnaires utilising the Enneking scoring system and Euroqol EQ-5D. There were 14 responses. The mean Enneking score was 58.0 % (34.3–77.1). Two patients were enthusiastic about their treatment, while three accepted but would not repeat the treatment. The Euroqol questionnaire found that 8 patients had difficulty with mobility, 10 had difficulty with usual activities and 12 had moderate pain. There was no statistically significant difference in the EQ VAS score of overall health state for treated patients compared with predicted scores for an age- and sex-matched UK population (77.7 vs 83.1, p = 0.07).

Evidence for high-energy extraterrestrial neutrinos at the IceCube detector

We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to about 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds. Combined, both searches reject a purely atmospheric origin for the 28 events at the 4σ level. These 28 events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.

Measurement of atmospheric neutrino oscillations with IceCube

We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

First observation of PeV-energy neutrinos with IceCube

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ν(e,μ,τ) (ν(e,μ,τ)) or charged-current ν(e) (ν(e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10(-3) (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.

Measurement of the atmospheric νe flux in IceCube

We report the first measurement of the atmospheric electron neutrino flux in the energy range between approximately 80 GeV and 6 TeV, using data recorded during the first year of operation of IceCube's DeepCore low-energy extension. Techniques to identify neutrinos interacting within the DeepCore volume and veto muons originating outside the detector are demonstrated. A sample of 1029 events is observed in 281 days of data, of which 496±66(stat)±88(syst) are estimated to be cascade events, including both electron neutrino and neutral current events. The rest of the sample includes residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is consistent with models of atmospheric neutrinos in this energy range. This constitutes the first observation of electron neutrinos and neutral current interactions in a very large volume neutrino telescope optimized for the TeV energy range.

Search for dark matter annihilations in the sun with the 79-string IceCube detector

We have performed a search for muon neutrinos from dark matter annihilation in the center of the Sun with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore subarray is included in the analysis, lowering the energy threshold and extending the search to the austral summer. The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos. Upper limits are set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent scattering cross sections of weakly interacting massive particles (WIMPs) on protons, for WIMP masses in the range 20-5000  GeV/c2. These are the most stringent spin-dependent WIMP-proton cross section limits to date above 35  GeV/c2 for most WIMP models.

Outcome of arthrodesis of the hindfoot as a salvage procedure for complex ankle pathology using the Ilizarov technique

Achieving arthrodesis of the ankle can be difficult in the presence of infection, deformity, poor soft tissues and bone loss. We present a series of 48 patients with complex ankle pathology, treated with the Ilizarov technique. Infection was present in 30 patients and 30 had significant deformity before surgery. Outcome was assessed clinically and with patient-reported outcome measures (Modified American Orthopaedic Foot and Ankle Society (MAOFAS) scale and the Short-Form (SF-36)).

Arthrodesis was achieved in 40 patients with the Ilizarov technique alone and in six further patients with additional surgery. Infection was eradicated in all patients at a mean follow-up of 46.6 months (13 to 162). Successful arthrodesis was less likely in those with comorbidities and in tibiocalcaneal fusion compared with tibiotalar fusion.

These patients had poor general health scores compared with the normal population before surgery. The mean MAOFAS score improved significantly from 24.3 (0 to 90) pre-operatively to 56.2 (30 to 90) post-operatively, but there was only a modest improvement in general health; the mean SF-36 improved from 44.8 (19 to 66) to 50.1 (21 to 76). There was a major benefit in terms of pain relief.

Arthrodesis using the Ilizarov technique is an effective treatment for complex ankle pathology, with good clinical outcomes and eradication of infection. However, even after successful arthrodesis general health scores remain limited.

Cite this article: Bone Joint J 2013;95-B:371–7.

Chemoresistant colorectal cancer cells and cancer stem cells mediate growth and survival of bystander cells

BACKGROUND

Recent studies suggest that cancer stem cells (CSCs) mediate chemoresistance, but interestingly, only a small percentage of cells in a resistant tumour are CSCs; this suggests that non-CSCs survive by other means. We hypothesised that chemoresistant colorectal cancer (CRC) cells generate soluble factors that enhance survival of chemonaive tumour cells.

METHODS

Chemoresistant CRC cells were generated by serial passage in oxaliplatin (Ox cells). Conditioned media (CM) was collected from parental and oxaliplatin-resistant (OxR) cells. CRC cells were treated with CM and growth and survival were assessed. Tumour growth rates were determined in nude mice after cells were treated with CM. Mass spectrometry (MS) identified proteins in CM. Reverse phase protein microarray assays determined signalling effects of CM in parental cells.

RESULTS

Oxaliplatin-resistant CM increased survival of chemo-naive cells. CSC CM also increased growth of parental cells. Parental and OxR mixed tumours grew larger than tumours composed of parental or OxR cells alone. Mass spectrometry detected unique survival-promoting factors in OxR CM compared with parental CM. Cells treated with OxR CM demonstrated early phosphorylation of EGFR and MEK1, with later upregulation of total Akt .We identified progranulin as a potential mediator of chemoresistance.

CONCLUSION

Chemoresistant tumour cells and CSCs may promote resistance through soluble factors that mediate survival in otherwise chemosensitive tumour cells.

Limits on neutrino emission from gamma-ray bursts with the 40 string IceCube detector

IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 10(18)  eV. Two separate analyses using the half-complete IceCube detector, one a dedicated search for neutrinos from pγ interactions in the prompt phase of the gamma-ray burst fireball and the other a generic search for any neutrino emission from these sources over a wide range of energies and emission times, produced no evidence for neutrino emission, excluding prevailing models at 90% confidence.

Chronic exposure of colorectal cancer cells to bevacizumab promotes compensatory pathways that mediate tumour cell migration

BACKGROUND

Bevacizumab (Bev), a monoclonal antibody to vascular endothelial growth factor (VEGF), is used in combination with chemotherapy for the treatment of metastatic colorectal cancer (CRC). The effects of Bev on angiogenesis have been well described, but the direct effect of Bev on tumour cells is unknown. This study was carried out to determine the molecular and phenotypic changes in CRC cells after chronic Bev exposure in vitro.

METHODS

Human CRC cell lines were chronically exposed (3 months) to Bev in vitro to develop Bev-adapted (Bev-A) cell lines. Vascular endothelial growth factor family members were determined by reverse transcription-polymerase chain reaction and western blotting. Migration and invasion was determined using standard in vitro assays. Intravenous injection of tumour cells was carried out to evaluate metastatic potential in mice.

RESULTS

Bevacizumab-adapted cells were found to be more migratory and invasive than control cells (P<0.001). Bevacizumab-adapted cells showed higher levels of VEGF-A, -B, -C, placental growth factor (PlGF), VEGF receptor-1 (VEGFR-1) and phosphorylation of VEGFR-1. Furthermore, treatment with SU5416, a VEGFR protein tyrosine kinase inhibitor, led to significantly decreased cell migration in vitro (P<0.001). Bevacizumab-adapted cells were more metastatic in vivo (P<0.05).

CONCLUSION

Chronic exposure of CRC cells to Bev (1) increased expression of VEGF-A, -B, -C, PlGF, VEGFR-1 and VEGFR-1 phosphorylation, (2) increased tumour cell migration and invasion, and (3) metastatic potential in vivo. Our study shows the functional significance of autocrine VEGF signalling in CRC cells.

Factors influencing the choice of drug therapy in primary and secondary health care

A prescribing decision model incorporating drug characteristics, professional opinions and past experience was used to predict the choices made by prescribers when selecting a non-steroidal anti-inflammatory drug (NSAID) for inclusion in a formulary. Thirty general practitioners (GPs) and 14 hospital doctors (HDs), most practising within the South East Thames regional health authority, were asked to select either ibuprofen, diclofenac or indomethacin, based on the needs of a described population, and then to answer a questionnaire.

Looking at the relative importance of factors influencing the choice of treatment, there was generally a high degree of agreement between HDs and GPs. However, the majority of HDs ranked efficacy as the most important drug characteristic whereas GPs were generally more concerned with side effects. Fundholding GPs ranked cost more highly than did their non-fundholding counterparts, and GPs working in single handed practices were more influenced by specialists and company representatives than were GPs working in groups. The decision model correctly predicted the drug choice of all the HDs and of 76 per cent of the GPs. These values were considerably better than the 33 per cent that would be predicted based on chance alone.

Although various limitations of this type of study are noted, it is hoped that the model could be developed as a valuable tool to assist in understanding complex prescribing issues.

Evaluation of glycolytic activity and HIF-1α expression in chemoresistant colorectal cancer cells

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Background: Overcoming drug resistance in colorectal cancer (CRC) involves understanding the mechanisms by which cancer cells adapt to the genotoxic stress. We established a model of oxaliplatin resistant cells derived from HCT116/HT29 (HCT116 OxR/HT29 OxR). How these resistant clones reprogram their energy metabolism to gain a survival advantage remains unknown. We hypothesized that chemoresistant CRC cells exhibit altered cellular metabolism to survive following chronic genotoxic stress.

Methods: The expression levels of glycolytic enzymes were detected by Western Blotting. Glucose and lactate concentrations were measured in the culturing media (CM). Intracellular ATP/ADP levels, oxygen consumption rate (OCR) and mitochondria ATP production were measured. In vivo xenograft study was used to compare the growth rate and angiogenesis of parental and oxaliplatin-resistant cells.

Results: Both HT29-OxR and HCT116-OxR cells compared to parental cells exhibit increased aerobic glycolysis. Consistently, Glut1, Hexokinase 2 and LDHA glycolytic enzymes are upregulated. The OxR cells are defective in mitochondria complex I/II substrate and ATP production despite increased OCR. Importantly, the OXR cells maintain higher intracellular ATP and ATP/ADP ratio, increased HIF1a and VEGF levels in the CM. In tumor xenograft model, HT29 OxR cells grow significant slower than parental HT29 cells. Interestingly, when OxR cells were mixed with parental HT29 cells (50:50 and 90:10), tumor growth and microvessel counts were significantly accelerated.

Conclusions: OxR cells demonstrate: 1) high aerobic glycolytic activity; 2) defective mitochondria functions; 3) increased ATP production; 4) increased HIF1a and angiogenesis. Likely, this metabolic switch contributes to the resistant phenotype. Metabolism intervention such as targeting HIF1a may provide a novel strategy to overcome drug-resistance in CRC.

No significant financial relationships to disclose.

Influence of pre-collision occupant parameters on injury outcome in a frontal collision

Optimal performance of adaptive restraint systems in the vehicle requires an accurate assessment of occupant characteristics including physical properties and pre-collision response of the occupant. To provide a feasible framework for incorporating occupant characteristics into adaptive restraint schemes, this study evaluates the sensitivity of injury risk in frontal collisions to four occupant parameters: mass, stature, posture and bracing level. The numerical approach includes using commercial multi-body software to develop occupant models that span a range of occupant parameters representative of the real-world driver population. Coupled with a multi-body model of the vehicle interior and standard restraint system, risk of occupant injuries within specific body regions are predicted through numerical simulations in conjunction with established injury risk functions. The results show occupant posture to be the most significant parameter affecting the overall risk of injury in frontal collisions. The causal relationship as predicted using the numerical model has been compared to the traffic injury epidemiology findings, and the feasibility of an analytical methodology to provide real-time estimates of injury severity has been discussed. Preliminary estimates from the study indicate that the proposed methodology will provide a framework to optimize restraint performance and potentially reduce the risk of injuries up to 35% (based on parameter-specific optimization), using accurate information regarding the pre-collision occupant characteristics.

A second paradigm for gene activation in bacteria

Control of gene expression is key to development and adaptation. Using purified transcription components from bacteria, we employ structural and functional studies in an integrative manner to elaborate a detailed description of an obligatory step, the accessing of the DNA template, in gene expression. Our work focuses on a specialized molecular machinery that utilizes ATP hydrolysis to initiate DNA opening and permits a description of how the events triggered by ATP hydrolysis within a transcriptional activator can lead to DNA opening and transcription. The bacterial EBPs (enhancer binding proteins) that belong to the AAA(+) (ATPases associated with various cellular activities) protein family remodel the RNAP (RNA polymerase) holoenzyme containing the sigma(54) factor and convert the initial, transcriptionally silent promoter complex into a transcriptionally proficient open complex using transactions that reflect the use of ATP hydrolysis to establish different functional states of the EBP. A molecular switch within the model EBP we study [called PspF (phage shock protein F)] is evident, and functions to control the exposure of a solvent-accessible flexible loop that engages directly with the initial RNAP promoter complex. The sigma(54) factor then controls the conformational changes in the RNAP required to form the open promoter complex.