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Objectives: Birthweight (BW) indicates newborn health and is a risk factor for development of chronic diseases later in life. The aim was to investigate whether or not prenatal physical activity (PA) influences BW extremes and how PA influences BW extremes in those diagnosed with pregnancy-related diseases., Design: We performed a scoping review., Methods: Searches were completed on five databases and studies identified were uploaded to Covidence., Results: Across the five databases 3114 studies were identified and after screening, 69 of these studies were used for the final review. Of the 61 studies that considered low BW (LBW)/small for gestational age (SGA) infants, the majority of results (69 %) indicated that PA during pregnancy had no significant impact on LBW or SGA infants. In addition, 11 % of studies reported a significant decrease in the prevalence of LBW infants, however two studies (3 %) reported a significant increase in LBW or SGA infants, likely relating to individuals with high body mass index and poor adherence to PA. Of the 41 studies that did report LGA/macrosomia, 34 % reported that PA significantly reduced the prevalence of higher BW infants. One study reported the association between meeting exercise recommendations and reducing the odds of LGA infants in those with pregnancy-related diseases., Conclusions: We provide evidence on the association of prenatal PA with BW extremes. It is suggested that prenatal PA does not increase the risk of delivering LBW/SGA infants and may reduce the prevalence of large BW infants. Further research is needed to confirm these relationships and explain their underlying mechanisms., Competing Interests: Declaration of competing interest We have no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Children's eating behaviors are dependent on childhood food experiences, which involve their parental feeding practices, home food environments, and modeling of eating behavior. Intuitive eating (IE) promotes eating based on internal hunger and satiety cues. IE has been associated with improvements in mental and physical health. There has been increasing interest in exploring the association between parent and child IE. The aim of this scoping review was to synthesize current literature reporting on parent and child IE associations. Four databases (MEDLINE, EMBASE, Web of Science and CINAHL) were searched using keywords focusing on IE, parents, and children. Inclusion criteria were reporting on parental and/or child IE, and reporting on parent-child relationships. After screening, 15 studies were retained. From these, 3 main correlations were described. Parental IE was associated with child feeding, child weight concerns, and the home food environment. As well, environmental factors (i.e., family cohesion, food security) were associated with components of child IE. Moreover, IE was directly correlated between parents and children. Overall, this study highlights how child IE behaviors may be shaped by both parental IE and the broader environments that they are raised within. Additional high-quality studies are required to verify these findings., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2024 The Author(s).)

We introduce an hp -version discontinuous Galerkin finite element method (DGFEM) for the linear Boltzmann transport problem. A key feature of this new method is that, while offering arbitrary order convergence rates, it may be implemented in an almost identical form to standard multigroup discrete ordinates methods, meaning that solutions can be computed efficiently with high accuracy and in parallel within existing software. This method provides a unified discretisation of the space, angle, and energy domains of the underlying integro-differential equation and naturally incorporates both local mesh and local polynomial degree variation within each of these computational domains. Moreover, general polytopic elements can be handled by the method, enabling efficient discretisations of problems posed on complicated spatial geometries. We study the stability and hp -version a priori error analysis of the proposed method, by deriving suitable hp -approximation estimates together with a novel inf-sup bound. Numerical experiments highlighting the performance of the method for both polyenergetic and monoenergetic problems are presented., Competing Interests: Conflict of interestThe authors declare that they have no Conflict of interest., (© The Author(s) 2024.)

Mesial temporal sclerosis (MTS) is a frequent cause of medically refractory epilepsy, for which laser interstitial thermal therapy (LITT) is an effective treatment. However, experience with the technical considerations posed by additional surgery after an initial LITT procedure is lacking. The authors present the case of a 12-year-old female with medically refractory temporal lobe epilepsy and left MTS who underwent LITT at a separate institution prior to referral. This patient had no change in early postoperative seizure control (Engel class IVB) and then her seizures worsened despite ongoing medical treatment (Engel class IVC). Post-LITT MRI revealed sparing of the mesial hippocampus head, a poor prognostic factor. The authors describe the technical details illustrated by this case of secondary, stereotactic electroencephalography-guided mesial temporal resection following LITT. The case was managed with anterior temporal lobectomy including the resection of residual hippocampus and amygdala.

Context: Autonomic dysreflexia (AD) is a complex syndrome seen in patients with spinal cord injuries (SCI) and can be life-threatening with a significant negative impact on the health of the individual. Posterior reversible encephalopathy syndrome (PRES) is thought to be caused, in part, by rapid elevations in blood pressure; leading to posterior cerebral circulatory edema. This can result in seizures, blindness and can progress to fatal intracranial hemorrhages. Findings: Here we present two cases of patients with SCI who developed PRES from AD. Each patient was correctly diagnosed, leading to appropriate treatment of the factors leading to their AD and subsequent resolution of their PRES symptoms. Conclusions/Clinical Relevance: In SCI patients who present with new seizures, visual deficits, or other neurologic signs, PRES should be considered as a part of the differential diagnosis as a good outcome relies on rapid recognition and treatment of AD.

Objective: Concussion is the most common type of brain injury in both pediatric and adult populations and can potentially result in persistent postconcussion symptoms. Objective assessment of physiologic "mild" traumatic brain injury in concussion patients remains challenging. This study evaluates an automated eye-tracking algorithm as a biomarker for concussion as defined by its symptoms and the clinical signs of convergence insufficiency and accommodation dysfunction in a pediatric population., Design: Cross-sectional case-control study., Setting: Primary care., Patients: Concussed children (N = 56; mean age = 13 years), evaluated at a mean of 22-week post-injury, compared with 83 uninjured controls., Independent Variables: Metrics comparing velocity and conjugacy of eye movements over time were obtained and were compared with the correlation between Acute Concussion Evaluation (ACE) scores, convergence, and accommodation dysfunction., Main Outcome Measures: Subjects' eye movements recorded with an automated eye tracker while they watched a 220-second cartoon film clip played continuously while moving within an aperture., Results: Twelve eye-tracking metrics were significantly different between concussed and nonconcussed children. A model to classify concussion as diagnosed by its symptoms assessed using the ACE achieved an area under the curve (AUC) = 0.854 (71.9% sensitivity, 84.4% specificity, a cross-validated AUC = 0.789). An eye-tracking model built to identify near point of convergence (NPC) disability achieved 95.8% specificity and 57.1% sensitivity for an AUC = 0.810. Reduced binocular amplitude of accommodation had a Spearman correlation of 0.752(P value <0.001) with NPC., Conclusion: Eye tracking correlated with concussion symptoms and detected convergence and accommodative abnormalities associated with concussion in the pediatric population. It demonstrates utility as a rapid, objective, noninvasive aid in the diagnosis of concussion.

Glioblastomas (GBMs) are the most aggressive primary brain tumours and have no known cure. Each individual tumour comprises multiple sub-populations of genetically-distinct cells that may respond differently to targeted therapies and may contribute to disappointing clinical trial results. Image-localized biopsy techniques allow multiple biopsies to be taken during surgery and provide information that identifies regions where particular sub-populations occur within an individual GBM, thus providing insight into their regional genetic variability. These sub-populations may also interact with one another in a competitive or cooperative manner; it is important to ascertain the nature of these interactions, as they may have implications for responses to targeted therapies. We combine genetic information from biopsies with a mechanistic model of interacting GBM sub-populations to characterise the nature of interactions between two commonly occurring GBM sub-populations, those with EGFR and PDGFRA genes amplified. We study population levels found across image-localized biopsy data from a cohort of 25 patients and compare this to model outputs under competitive, cooperative and neutral interaction assumptions. We explore other factors affecting the observed simulated sub-populations, such as selection advantages and phylogenetic ordering of mutations, which may also contribute to the levels of EGFR and PDGFRA amplified populations observed in biopsy data.

Objectives: Tracheostomy is a basic surgical procedure that most surgeons, regardless of specialty, learn early in their training. With improvements in intensive care medicine, the number of neurosurgical patients requiring tracheostomy has declined. As neurosurgeons advance in their training, familiarity with airway management declines and falls under the domain of other specialties. Because neurosurgeons still manage critically ill patients, they often defer the airway management to other specialists. In many institutions, neurosurgeons no longer perform tracheostomies. The purpose of this study was to evaluate complications and outcomes following tracheostomies performed by neurosurgeons., Patients and Methods: We reviewed a database of all neurosurgical procedures performed at a single institution from 9/2007 to 2/2017. We reviewed the operative and medical records of patients whose tracheostomies were performed by a neurosurgeon., Results: Neurosurgeons performed 72 tracheostomies over the study period. All the procedures were done in an operating room using traditional open technique. Four patients had previous tracheostomy. Five patients were on dual antiplatelet therapy. The procedure was successful in all patients. There were no immediate complications in any patient. One patient required revision for development of tracheo-cutaneous fistula., Conclusion: Tracheostomies can be performed safely by neurosurgeons in this era of sub-specialization. There is a renewed interest in maintaining critical care proficiency in neurosurgery. Airway management is an important part of this skill-set. Neurosurgeons manage patients with brain injuries, cranial nerve deficits, and cervical spine injuries, Consequently, learning how to establish a surgical airway remains necessary in neurosurgical training., (Copyright © 2020. Published by Elsevier B.V.)

Adequate drug distribution through tumors is essential for treatment to be effective. Palbociclib is a cyclin-dependent kinase 4/6 inhibitor approved for use in patients with hormone receptor positive, human epidermal growth factor receptor 2 negative metastatic breast cancer. It has unusual physicochemical properties, which may significantly influence its distribution in tumor tissue. We studied the penetration and distribution of palbociclib in vitro, including the use of multicellular three-dimensional models and mathematical modeling. MCF-7 and DLD-1 cell lines were grown as single cell suspensions (SCS) and spheroids; palbociclib uptake and efflux were studied using liquid chromatography-tandem mass spectrometry. Intracellular concentrations of palbociclib for MCF-7 SCS ( C max 3.22 µ M) and spheroids ( C max 2.91 µ M) were 32- and 29-fold higher and in DLD-1, 13- and 7-fold higher, respectively, than the media concentration (0.1 μ M). Total palbociclib uptake was lower in DLD-1 cells than MCF-7 cells in both SCS and spheroids. Both uptake and efflux of palbociclib were slower in spheroids than SCS. These data were used to develop a mathematical model of palbociclib transport that quantifies key parameters determining drug penetration and distribution. The model reproduced qualitatively most features of the experimental data and distinguished between SCS and spheroids, providing additional support for hypotheses derived from the experimental data. Mathematical modeling has the potential for translating in vitro data into clinically relevant estimates of tumor drug concentrations. SIGNIFICANCE STATEMENT: This study explores palbociclib uptake and efflux in single cell suspension and spheroid models of cancer. Large intracellular concentrations of palbociclib are found after drug exposure. The data from this study may aid understanding of the intratumoural pharmacokinetics of palbociclib, which is useful in understanding how drug distributes within tumor tissue and optimizing drug efficacy. Biomathematical modelling has the potential to derive intratumoural drug concentrations from plasma pharmacokinetics in patients., (Copyright © 2019 by The American Society for Pharmacology and Experimental Therapeutics.)

Introduction: Traumatic brain injury (TBI) is a major public health problem, particularly in children. Prognostication of injury severity at the time of presentation is difficult. The Abbreviated Injury Scale (AIS) is a commonly used anatomical-based coding system created to classify and describe injury severity after initial presentation, once test results are able to better define the anatomical characteristics of the injury. We hypothesize that the Head AIS can predict discharge destination in children after TBI., Methods: The trauma registry database for a Pediatric Level 1 Trauma center was queried for patients age ≤14 years from 2006 to 2015 with a Head AIS>2. All diagnoses with head AIS>2 were retrieved. Since one patient can have multiple diagnoses with an AIS>2, we selected the diagnosis with highest Head AIS associated with each patient. The demographics, length of stay, and the discharge disposition of patients were retrieved. Descriptive statistics were performed and association of Head AIS with the length of stay and discharge disposition was determined using logistic regression., Results: 393 pediatric patients (age≤14 years) with an Head AIS ≥3, (64.0% males, mean age = 6.2 S.D. 4.58) presented over 10 years. Head AIS was strongly associated with mortality; with 0.8%, 1.1% and 42.0% of patients with Head AIS of 3, 4 and 5, respectively, dying - odds ratio for Head AIS 5 over Head AIS 3 = 89 (logistic regression, p-value<0.001). 80.0% of deaths (23 patients) in this cohort occurred within 24-h of presentation. Head AIS was associated with an increase likelihood of discharge to rehabilitation with 1.2%, 7.7% and 47.0% of survivors discharging to rehabilitation for Head AIS of 3, 4 and 5., Conclusion: Head AIS can reliably predict discharge disposition to home, rehab or death. Calculation of Head AIS prior to discharge could lead to accurate prediction of discharge destination.

OBJECTIVEChronic subdural hematoma (cSDH) is a highly morbid condition associated with brain atrophy in the elderly. It has a reported 30% 1-year mortality rate. Approximately half of afflicted individuals report either no or relatively unremarkable trauma preceding their diagnosis, raising the possibility that cSDH is a manifestation of degenerative or inflammatory disease rather than trauma. The purpose of this study was to compare the rates of cerebral atrophy before and after cSDH to determine whether it is more likely that cSDH causes atrophy or that atrophy causes cSDH. The authors also compared atrophy rates in patients with cSDH to the rates in patients with and without dementia.METHODSThe authors developed algorithmic segmentation analysis software to measure whole-brain, CSF, and intracranial space volumes. They then identified military veterans who had undergone at least 4 brain CT scans over a period of 10 years. Within this database, the authors identified 146 patients with 962 head CT scans who had received diagnoses of either cSDH, dementia, or no known dementia condition. Volumetric analyses of brains in 45 patients with dementia (dementia group) and 73 patients without dementia (nondementia group), in whom 262 and 519 head CT scans were obtained, respectively, were compared with 11 patients in whom 81 CT scans were obtained a mean of 4.21 years before a cSDH diagnosis and 17 patients in whom 100 scans were obtained a mean of 4.24 years after SDH. Longitudinal measures were then related to disease status and the time since first scan by using hierarchical models, and atrophy rates between the groups were compared.RESULTSHead CT scans from patients were obtained for an average time period of 4.21 years (SD 1.69) starting at a mean patient age of 74 years. Absolute brain volume loss for the 17 patients in the post-SDH group (13 were treated surgically) was significantly greater, at 16.32 ml/year, compared with 6.61 ml/year in patients with dementia, 5.33 ml/year in patients without dementia, and 3.57 ml/year in pre-SDH patients. The atrophy rate for these individuals prior to enrollment in the study was 2.32 ml/year (p = 0.001). In terms of brain volume normalized to cranial cavity size, the post-SDH group had an atrophy rate of 0.7801%/year, compared with 0.4467%/year in patients with dementia, 0.3474%/year in patients without dementia, and 0.2135%/year in the pre-SDH group.CONCLUSIONSPrior to development of a cSDH, the atrophy rates in patients who ultimately develop cSDH are similar to those of patients without dementia. After development of a cSDH, the atrophy rates increase to more than twice those of patients with dementia. Chronic subdural hematoma is thus associated with a significant increase in brain atrophy rate. These findings suggest the neurotoxic consequences of cSDH and may have implications for better understanding of the pathophysiology of cerebral atrophy and dementia.

Sport Concussion Assessment Tool version 3 (SCAT-3) is one of the most widely researched concussion assessment tools in athletes. Here normative data for SCAT3 in nonathletes are presented. The SCAT3 was administered to 98 nonathlete healthy controls, as well as 118 participants with head-injury and 46 participants with other body trauma (OI) presenting to the ED. Reference values were derived and classifier functions were built to assess the accuracy of SCAT3. The control population had a mean of 2.30 (SD = 3.62) symptoms, 4.38 (SD = 8.73) symptom severity score (SSS), and 26.02 (SD = 2.52) standardized assessment of concussion score (SAC). Participants were more likely to be diagnosed with a concussion (from among healthy controls) if the SSS > 7; or SSS ≤ 7 and SAC ≤22 (sensitivity = 96%, specificity = 77%). Identification of head injury patients from among both, healthy controls and body trauma was possible using rule SSS > 7 and headache or pressure in head present, or SSS ≤ 7 and SAC ≤ 22 (sensitivity = 87%, specificity = 80%). In this current study, the SCAT-3 provided high sensitivity to discriminate acute symptoms of TBI in the ED setting. Individuals with a SSS > 7 and headache or pressure in head, or SSS ≤ 7 but with a SAC ≤ 22 within 48-hours of an injury should undergo further testing.

Background: Current animal models of glioma are limited to small animal models, which are less predictive of treatment of human disease. Canines often develop gliomas de novo, but the natural history of the disease is not well described., Objective: We provide data for naturally occurring canine gliomas; evaluating medical and surgical therapies., Methods: We reviewed medical records of pet dogs with a presumptive diagnosis of glioma from MRI imaging that underwent surgery as part of the Canine Brain Tumor Clinical Trials Program. Breed, age, sex, median progression-free, and overall survival times and cause of death were recorded for multivariate analysis., Results: Ninety five dogs (56 male; mean age = 8.3 years) were included, but nine were excluded as final pathology was non-neoplastic. Gross total resection was reported in 81 cases based on postoperative MRI. Seventy had high-grade tumors (grade III or IV). Eighty three dogs presented with seizures, being the most common presenting clinical sign. Median survival after surgery was 723 days (95% CI 343-1103) for grade II tumors, 301 days (197-404) for grade III and 200 days (126-274) for grade IV (p = .009 Kaplan-Meier survival analysis; Log Rank test). Age (cox regression, p = .14) or sex (Kaplan-Meier test, p = .22) did not predict survival., Conclusions: This study establishes normative data for a model exploiting dogs with naturally occurring glioma, which can be used to test novel therapies prior to translation to human trials. Further work will focus on the effects of different therapies, including chemotherapy, radiation therapy, and immunotherapy.

Congenital scoliosis due to a hemivertebra requires surgical stabilization prior to skeletal maturity if rapidly progressive curve growth occurs. Here the authors present the unique case of a man who, at the age of 12 years, had undergone Harrington rod placement for stabilization of progressive congenital scoliosis due to a T-11 hemivertebra and then, at the age of 53 years, presented with acutely progressive myelopathy due to spinal cord compression from an arachnoid web at T-11 despite a solid fusion mass at the prior surgical site. The patient underwent a posterior midline approach for resection of the T-11 pedicle at the level of the hemivertebra, intradural spinal cord detethering with resection of the arachnoid web at T-11, and T2-L2 instrumented fusion with deformity correction, leading to subsequent resolution of his acute myelopathic symptoms. In conclusion, arachnoid web formation superimposed on preexisting tension on the thoracic spinal cord from congenital scoliosis due to a T-11 hemivertebra caused acute myelopathy in an adult with a previously solid fusion mass from childhood. The resolution of acute myelopathy and halting of further progression occurred with pedicle resection, arachnoid web fenestration, and spinal deformity correction.

Background: Despite the importance of case logs in evaluating residents, no studies assess their accuracy in neurological surgery. Studies from other specialties reveal variations in reporting. This study assesses the accuracy of neurological surgery resident case logs at a single institution., Methods: Data was collected from three databases: billing data and two separate resident-managed case logs [department log and Accreditation Council for Graduate Medical Education (ACGME) case logs], containing records of procedures performed by 14 neurological surgery residents at a single institution over a 1-year period. The billing data was used as a proxy for a census of procedures performed during the study period. The difference between the number of procedures logged by residents and the number of procedures billed was calculated to determine the accuracy of the resident case logs., Results: Over the study period, 2150 procedures were billed at the institution, whereas 1749 procedures were logged in the ACGME case log and 1873 in the department log, representing an error rate of -18.65% and -12.88%, respectively. The error rate varied significantly (-1150% to +50.23%) between ACGME procedure categories. In 13 of the 22 ACGME procedure categories, the procedures were under-logged by residents in both resident-managed case logs. No category demonstrated over-logging in both case log systems., Conclusion: Resident managed case logs are an incomplete representation of clinical work. The cause for inaccuracy is multifactorial. The authors suggested that further research is necessary to validate their results and to identify means by which the accuracy of case logs can be increased., Competing Interests: There are no conflicts of interest.

The tumour vasculature and microenvironment is complex and heterogeneous, contributing to reduced delivery of cancer drugs to the tumour. We have developed an in silico model of drug transport in a tumour cord to explore the effect of different drug regimes over a 72 h period and how changes in pharmacokinetic parameters affect tumour exposure to the cytotoxic drug doxorubicin. We used the model to describe the radial and axial distribution of drug in the tumour cord as a function of changes in the transport rate across the cell membrane, blood vessel and intercellular permeability, flow rate, and the binding and unbinding ratio of drug within the cancer cells. We explored how changes in these parameters may affect cellular exposure to drug. The model demonstrates the extent to which distance from the supplying vessel influences drug levels and the effect of dosing schedule in relation to saturation of drug-binding sites. It also shows the likely impact on drug distribution of the aberrant vasculature seen within tumours. The model can be adapted for other drugs and extended to include other parameters. The analysis confirms that computational models can play a role in understanding novel cancer therapies to optimize drug administration and delivery., Competing Interests: The authors declare no competing interests.

In this work, we present a pedagogical tumour growth example, in which we apply calibration and validation techniques to an uncertain, Gompertzian model of tumour spheroid growth. The key contribution of this article is the discussion and application of these methods (that are not commonly employed in the field of cancer modelling) in the context of a simple model, whose deterministic analogue is widely known within the community. In the course of the example, we calibrate the model against experimental data that are subject to measurement errors, and then validate the resulting uncertain model predictions. We then analyse the sensitivity of the model predictions to the underlying measurement model. Finally, we propose an elementary learning approach for tuning a threshold parameter in the validation procedure in order to maximize predictive accuracy of our validated model.

In this work, we consider the spatial homogenization of a coupled transport and fluid-structure interaction model, to the end of deriving a system of effective equations describing the flow, elastic deformation and transport in an active poroelastic medium. The 'active' nature of the material results from a morphoelastic response to a chemical stimulant, in which the growth time scale is strongly separated from other elastic time scales. The resulting effective model is broadly relevant to the study of biological tissue growth, geophysical flows (e.g. swelling in coals and clays) and a wide range of industrial applications (e.g. absorbant hygiene products). The key contribution of this work is the derivation of a system of homogenized partial differential equations describing macroscale growth, coupled to transport of solute, that explicitly incorporates details of the structure and dynamics of the microscopic system, and, moreover, admits finite growth and deformation at the pore scale. The resulting macroscale model comprises a Biot-type system, augmented with additional terms pertaining to growth, coupled to an advection-reaction-diffusion equation. The resultant system of effective equations is then compared with other recent models under a selection of appropriate simplifying asymptotic limits.

Measurement of a tissue-specific electrical resistance may offer a discriminatory metric for evaluation of tissue health during cancer surgery. With a move toward minimally-invasive procedures, applicable contact sensing modalities must be scalable, fast and robust. A passive resistance characterisation method utilising a biogalvanic cell as an intrinsic power source has been proposed as a potentially suitable solution. Previous work has evaluated this system with results showing effective discrimination of tissue type and damage (through electroporation). However, aspects of the biogalvanic cell have been found to influence the characterisation performance, and are not currently accounted for within the system model. In particular, the electrode and salt-bridge resistance are not independently determined, leading to over-predictions of tissue resistivity. This paper describes a more comprehensive model and characterisation scheme, with electrode parameters and salt-bridge resistivity being evaluated independently. In a generalised form, the presented model illustrates how the relative resistive contributions from the electrodes and medium relate to the existing characterisation method efficacy. We also describe experiments with physiologically relevant salt solutions (1.71, 17.1, 154 mM), used for validation and comparison. The presented model shows improved performance over the current biogalvanic measurement technique at the median conductivity. Both the proposed and extant system models become unable to predict conductivity accurately at high conductivity due to the dominance of the electrodes. The characterisation techniques have also been applied to data collected on freshly excised human colon tissue (healthy and cancerous). The findings suggest that the resistance of the cell under the test conditions is electrode dominated, leading to erroneous tissue resistance determination. Measurement optimisation strategies and the surgical applicability of the biogalvanic technique are discussed in light of these findings.

The ability to predict how far a drug will penetrate into the tumour microenvironment within its pharmacokinetic (PK) lifespan would provide valuable information about therapeutic response. As the PK profile is directly related to the route and schedule of drug administration, an in silico tool that can predict the drug administration schedule that results in optimal drug delivery to tumours would streamline clinical trial design. This paper investigates the application of mathematical and computational modelling techniques to help improve our understanding of the fundamental mechanisms underlying drug delivery, and compares the performance of a simple model with more complex approaches. Three models of drug transport are developed, all based on the same drug binding model and parametrized by bespoke in vitro experiments. Their predictions, compared for a 'tumour cord' geometry, are qualitatively and quantitatively similar. We assess the effect of varying the PK profile of the supplied drug, and the binding affinity of the drug to tumour cells, on the concentration of drug reaching cells and the accumulated exposure of cells to drug at arbitrary distances from a supplying blood vessel. This is a contribution towards developing a useful drug transport modelling tool for informing strategies for the treatment of tumour cells which are 'pharmacokinetically resistant' to chemotherapeutic strategies.

In this paper we present a continuum mathematical model of vascular tumour growth which is based on a multiphase framework in which the tissue is decomposed into four distinct phases and the principles of conservation of mass and momentum are applied to the normal/healthy cells, tumour cells, blood vessels and extracellular material. The inclusion of a diffusible nutrient, supplied by the blood vessels, allows the vasculature to have a nonlocal influence on the other phases. Two-dimensional computational simulations are carried out on unstructured, triangular meshes to allow a natural treatment of irregular geometries, and the tumour boundary is captured as a diffuse interface on this mesh, thereby obviating the need to explicitly track the (potentially highly irregular and ill-defined) tumour boundary. A hybrid finite volume/finite element algorithm is used to discretise the continuum model: the application of a conservative, upwind, finite volume scheme to the hyperbolic mass balance equations and a finite element scheme with a stable element pair to the generalised Stokes equations derived from momentum balance, leads to a robust algorithm which does not use any form of artificial stabilisation. The use of a matrix-free Newton iteration with a finite element scheme for the nutrient reaction-diffusion equations allows full nonlinearity in the source terms of the mathematical model. Numerical simulations reveal that this four-phase model reproduces the characteristic pattern of tumour growth in which a necrotic core forms behind an expanding rim of well-vascularised proliferating tumour cells. The simulations consistently predict linear tumour growth rates. The dependence of both the speed with which the tumour grows and the irregularity of the invading tumour front on the model parameters is investigated., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Object: Skiing and snowboarding injuries have increased with the popularity of these sports. Spinal cord injuries (SCIs) are a rare but serious event, and a major cause of morbidity and mortality for skiers and snowboarders. The purpose of this study is to characterize the patterns of SCI in skiers and snowboarders., Methods: The authors queried the Nationwide Inpatient Sample for the years 2000-2008 for all patients admitted with skiing or snowboarding as the mechanism of injury, yielding a total of 8634 patients. The injury patterns were characterized by the ICD-9 diagnostic and procedure codes. The codes were searched for those pertaining to vertebral and skull fracture; spinal cord, chest, abdominal, pelvic, and vessel injuries; and fractures and dislocations of the upper and lower extremity. Statistical analysis was performed with ANOVA and Student t-test., Results: Patients were predominantly male (71%) skiers (61%), with the average age of the skiers being older than that of snowboarders (39.5 vs 23.5 years). The average length of stay for patients suffering from spine trauma was 3.8 days and was increased to 8.9 days in those with SCI. Among hospitalized patients, SCI was seen in 0.98% of individuals and was equally likely to occur in snowboarders and skiers (1.07% vs 0.93%, p < 0.509). Cervical spine trauma was associated with the highest likelihood of SCI (19.6% vs. 10.9% of thoracic and 6% of lumbar injuries, p < 0.0001). Patients who were injured skiing were more likely to sustain a cervical spine injury, whereas those injured snowboarding had higher frequencies of injury to the lumbar spine. The most common injury seen in tandem with spine injury was closed head injury, and it was seen in 13.4% of patients. Conversely, a spine injury was seen in 12.9% of patients with a head injury. Isolated spine fractures were seen in 4.6% of patients., Conclusions: Skiers and snowboarders evaluated at the hospital are equally likely to sustain spine injuries. Additionally, participants in both sports have an increased incidence of SCI with cervical spine trauma.

Published research indicates that regular use of toothpaste containing sodium bicarbonate is effective in reducing volatile sulfur compounds (VSCs) and oral malodor. Gaffar initially reported on the use of sodium bicarbonate as an agent to affect VSCs, indicating that sodium bicarbonate had the potential to alter the VSCs to nonvolatile compounds. Chewing gum would also be suspected of providing benefits in controlling oral malodor through its claimed ability to mechanically aid in the removal of dental plaque. Based on the length of chewing time, the opportunity exists for chewing gum to reach places in the mouth that might be missed during brushing. This activity could contribute to reductions in the amount of viable plaque mass that could produce VSCs.

The R/B and Minitek systems for the identification of Enterobacteriaceae were evaluated, and the results were compared with those obtained by conventional methods. Both systems were rapid and allowed correct identification of about 85% of the 294 isolates (23 species) examined. The individual biochemical reactions showed an overall agreement of 92.6% and 93.1% for the R/B and Minitek systems, respectively.

The reliability of the Enteric Analyzer for identification of Enterobacteriaceae was evaluated using biochemical results previously obtained for 291 organisms with the conventional, R/B, and Minitek systems. The instrument correctly identified 77.3% of the organisms using conventional system results, 74.2% using R/B results, and 60.5% using Minitek results. The low rate of identification with the conventional system occurs primarily because the instrument is not programmed to consider delayed biochemical reactions. The arbitrary use of 90% and 99% probabilities for test reactions also contributes to a lower percentage of identification. The Enteric Analyzer does not replace the judgment of experienced personnel in the identification of atypical bacteria, but it may prove helpful in speeding up final computer identification of typical microorganisms.