Habitat selection of resident and non-resident gray wolves: implications for habitat connectivity

Habitat selection studies facilitate assessing and predicting species distributions and habitat connectivity, but habitat selection can vary temporally and among individuals, which is often ignored. We used GPS telemetry data from 96 Gray wolves (Canis lupus) in the western Great Lakes region of the USA to assess differences in habitat selection while wolves exhibited resident (territorial) or non-resident (dispersing or floating) movements and discuss implications for habitat connectivity. We used a step-selection function (SSF) to assess habitat selection by wolves exhibiting resident or non-resident movements, and modeled circuit connectivity throughout the western Great Lakes region. Wolves selected for natural land cover and against areas with high road densities, with no differences in selection among wolves when resident, dispersing, or floating. Similar habitat selection between resident and non-resident wolves may be due to similarity in environmental conditions, when non-resident movements occur largely within established wolf range rather than near the periphery or beyond the species range. Alternatively, non-resident wolves may travel through occupied territories because higher food availability or lower human disturbance outweighs risks posed by conspecifics. Finally, an absence of differences in habitat selection between resident and non-resident wolf movements may be due to other unknown reasons. We recommend considering context-dependency when evaluating differences in movements and habitat use between resident and non-resident individuals. Our results also provide independent validation of a previous species distribution model and connectivity analysis suggesting most potential wolf habitat in the western Great Lakes region is occupied, with limited connectivity to unoccupied habitat.

Effectiveness of wheelchair skills training for improving manual wheelchair mobility in children and adolescents: protocol for a multicenter randomized waitlist-controlled trial

BACKGROUND

Self-directed mobility during childhood can influence development, social participation, and independent living later in life. For children who experience challenges with walking, manual wheelchairs (MWCs) provide a means for self-directed mobility. An effective MWC skills training program exists for adults, but controlled trials have not yet been documented in children and adolescents. This paper outlines the protocol for a multi-centre randomized wait-list controlled trial. The primary objective is to test the hypothesis that children and adolescents who receive MWC skills training will have higher MWC skills capacity compared to children and adolescents in the control group who receive usual care. The secondary objectives are to explore the influence of MWC skills training in children and adolescents (MWC use self-efficacy and satisfaction with participation in meaningful activities), and parents (perceived MWC skills); and to measure retention three months later.

METHODS

A multi-centre, parallel-group, single-blind randomized wait-list controlled trial will be conducted. A sample of 60 children and adolescents who use MWCs will be recruited in rehabilitation centres, specialized schools, and the communities of three Canadian cities. Participants will be randomized (1:1) to the experimental (Wheelchair Skills Training Program [WSTP]) or wait-list control group (usual care). Performance-based and self-report measures will be completed at baseline (T1), three months (post-intervention, T2), and three months post-intervention (T3). The primary outcome will be MWC skills capacity post-intervention. Secondary outcomes will be MWC use self-efficacy and satisfaction with participation of the child/adolescent, and parent-perceived MWC skills. The WSTP will consist of 12 sessions, 45-60 min each, delivered 1-2 times per week by trained personnel with health professions education. Training will be customized according to the child's baseline skills and participation goals that require the use of the MWC. The wait-list control group will receive usual care for 3 months and then receive the WSTP after completing T2 evaluations. Data will be analysed using ANCOVA (controlling for baseline scores).

DISCUSSION

MWC skills training may be one way to improve self-directed mobility and related outcomes for children and adolescents. The results of this multi-centre randomized wait-list controlled trial will allow for the effectiveness of the intervention to be evaluated in a variety of clinical contexts and geographical regions.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05564247, Version October 3, 2022.

A-28 Systematic Review And Meta-Analysis Of Factors Influencing Sport Concussion For Athletes with ADHD and/or LD

Purpose: Purpose: Athletes with Attention-Deficit/Hyperactivity Disorder (ADHD) and/or Learning Disorder (LD) are at increased risk for sport concussion and require specialized attention. Although systematic reviews of ADHD/LD and concussion are reported, no meta-analyses have been conducted. Additionally, no reviews focused on the most common concussion assessment, ImPACT. Methods: Data Selection: The current review used PRISMA guidelines. Searches utilized PubMed, Web of Science, and PsycINFO. Articles selected for this meta-analysis examined ADHD and/or LD (high school and collegiate athletes) using ImPACT from 2000–2021. Topics included: 1) baseline and 2) post-concussion performance on ImPACT, 3) symptom reporting using the Post-Concussion Symptom Scale, 4) invalid baseline classification on ImPACT, 5) concussion rates, and 6) concussion recovery. 10,163 articles were identified. 39 were included in review and 19 were included in random-effects meta-analyses on topics 1, 3, 4, and 5. Results: Data Synthesis: Meta-analysis results found decreased baseline performance on ImPACT for athletes with ADHD (trivial to small effects), LD (small to medium effects), and ADHD/LD (small to medium effects). Increased symptom reporting was found for athletes with ADHD (small effect). Increased odds of invalid ImPACT baseline performance (trivial effect) and concussion (small effect) were found in ADHD. Conclusions: Athletes with ADHD and/or LD demonstrate differences on ImPACT in cognitive performance, symptom reporting, and concussion risk (particularly for ADHD). Most research focused on ADHD. Future work should further examine athletes with LD and co-occurring ADHD/LD as well as the effects that these conditions can have on concussion recovery, given the mixed literature in that regard.

Mllt11 Regulates Migration and Neurite Outgrowth of Cortical Projection Neurons during Development

The formation of connections within the mammalian neocortex is highly regulated by both extracellular guidance mechanisms and intrinsic gene expression programs. There are two types of cortical projection neurons (CPNs): those that project locally and interhemispherically and those that project to subcerebral structures such as the thalamus, hindbrain, and spinal cord. The regulation of cortical projection morphologies is not yet fully understood at the molecular level. Here, we report a role for Mllt11 (Myeloid/lymphoid or mixed-lineage leukemia; translocated to chromosome 11/All1 Fused Gene From Chromosome 1q) in the migration and neurite outgrowth of callosal projection neurons during mouse brain formation. We show that Mllt11 expression is exclusive to developing neurons and is enriched in the developing cortical plate (CP) during the formation of the superficial cortical layers. In cultured primary cortical neurons, Mllt11 is detected in varicosities and growth cones as well as the soma. Using conditional loss-of-function and gain-of-function analysis we show that Mllt11 is required for neuritogenesis and proper migration of upper layer CPNs. Loss of Mllt11 in the superficial cortex of male and female neonates leads to a severe reduction in fibers crossing the corpus callosum (CC), a progressive loss in the maintenance of upper layer projection neuron gene expression, and reduced complexity of dendritic arborization. Proteomic analysis revealed that Mllt11 associates with stabilized microtubules, and Mllt11 loss affected microtubule staining in callosal axons. Taken together, our findings support a role for Mllt11 in promoting the formation of mature upper-layer neuron morphologies and connectivity in the cerebral cortex.SIGNIFICANCE STATEMENT The regulation of cortical projection neuron (CPN) morphologies is an area of active investigation since the time of Cajal. Yet the molecular mechanisms of how the complex dendritic and axonal morphologies of projection neurons are formed remains incompletely understood. Although conditional mutagenesis analysis in the mouse, coupled with overexpression assays in the developing fetal brain, we show that a novel protein called Mllt11 is sufficient and necessary to regulate the dendritic and axonal characteristics of callosal projection neurons in the developing mammalian neocortex. Furthermore, we show that Mllt11 interacts with microtubules, likely accounting for its role in neuritogenesis.

The independent and interactive associations of physical activity intensity and vitamin D status with bone mineral density in prepubertal children: the PANIC Study

It is unclear how physical activity intensity and vitamin D status are related to bone health in prepubertal children. We found positive associations between vitamin D status and moderate-to-vigorous physical activity with bone in boys and girls. This highlights the importance of lifestyle factors for skeletal health prepuberty.

INTRODUCTION

The sex-specific independent and interactive associations of physical activity (PA) intensity and serum 25-hydroxyvitamin D (25(OH)D) levels with areal bone mineral density (aBMD) were investigated in prepubertal children.

METHODS

The participants were 366 prepubertal Finnish children (190 boys, 176 girls) aged 6-8 years. Linear regression analysed the associations of sedentary time (ST), light PA (LPA), moderate PA (MPA), moderate-to-vigorous PA (MVPA) and vigorous PA (VPA) measured by accelerometery, and serum 25(OH)D with total body less head (TBLH) and lower-limb aBMD, measured by dual-energy X-ray absorptiometry.

RESULTS

There was no interaction between PA intensity or serum 25(OH)D and sex with aBMD. MPA and MVPA were positively associated with TBLH and lower-limb aBMD (β = 0.11, 95% CI 0.02-0.20, p = 0.01). Serum 25(OH)D was positively associated with TBLH and lower-limb aBMD (β = 0.09, 95% CI 0.01-0.18, p = 0.03). There were no interactions between PA intensity and serum 25(OH)D with aBMD.

CONCLUSION

Vitamin D status, MPA and MVPA levels in active prepubertal children were positively associated with aBMD. The influence of MVPA is due to the MPA component, though our findings regarding the role of VPA should be interpreted with caution, as shorter accelerometer epochs are needed to more accurately assess VPA. This study adds evidence to the promotion of MPA and behaviours to encourage optimal vitamin D status in supporting skeletal health in childhood, though these need not be used in conjunction to be beneficial, and a sex-specific approach is not necessary in prepubertal children.

TRIAL REGISTRATION NUMBER

NCT01803776 . Date of registration: 4/03/2013.

Development of the mammalian cortical hem and its derivatives: the choroid plexus, Cajal-Retzius cells and hippocampus

The dorsal medial region of the developing mammalian telencephalon plays a central role in the patterning of the adjacent brain regions. This review describes the development of this specialized region of the vertebrate brain, called the cortical hem, and the formation of the various cells and structures it gives rise to, including the choroid plexus, Cajal–Retzius cells and the hippocampus. We highlight the ontogenic processes that create these different forebrain derivatives from their shared embryonic origin and discuss the key signalling pathways and molecules that influence the patterning of the cortical hem. These include BMP, Wnt, FGF and Shh signalling pathways acting with Homeobox factors to carve the medial telencephalon into district progenitor regions, which in turn give rise to the choroid plexus, dentate gyrus and hippocampus. We then link the formation of the lateral ventricle choroid plexus with embryonic and postnatal neurogenesis in the hippocampus.

A CTSA One Health Alliance guidance on institutional review of veterinary clinical studies

Harmonized institutional processes and reviewer training are vital to maintain integrity and ethical rigor of the veterinary clinical research pipeline and are a prerequisite to future work that might establish centralized or single-site ethical and regulatory review to ease initiation of multi-center studies. Funded by a CTSA One Health Alliance (COHA) pilot award, a diverse working group of veterinary clinicians and institutional representatives was convened in February 2020 to develop a guidance document detailing broadly agreed upon practices for ethical review and approval of veterinary clinical studies conducted in the United States.The working group defined key areas of need for consensus, developed a set of associated guidelines, and circulated these for review by COHA's fifteen member institutions. Six focus areas were identified by the working group and included vital items of protocol review, composition of the review committee, post-approval monitoring and adverse event reporting, consideration of special circumstances such as satellite sites and the use of healthy veterinary subjects in research, and the informed consent process.This document outlines a broadly agreed-upon framework through which to approach vital items associated with veterinary clinical study protocol review and approval. These approaches represent current best practice in the review and approval of veterinary clinical studies, and can serve as a guidance for veterinary clinician-scientists and regulatory experts, to ensure robust and ethically conducted studies that can contribute to the advancement of both animal and human health.

NUT Carcinoma in a Patient with Unusually Long Survival and False Negative FISH Results

Nuclear protein in testis (NUT) carcinoma is a rare and highly aggressive epithelial malignancy defined by rearrangement of the NUTM1 gene on chromosome 15q14. Histologically, NUT carcinoma is an undifferentiated carcinoma formed by sheets and nests of primitive and monotonous "round blue cells" with foci of abrupt keratinization in a subset. NUT carcinoma runs a fulminant clinical course and is almost always quickly lethal, with a median overall survival of only 6.7 months. There is no consensus regarding treatment for this disease, and most patients respond poorly to conventional chemotherapy and radiation. We report a case of NUT carcinoma in an African-American man who initially presented in 2009 with a tracheal mass at age 28. Although fluorescence in situ hybridization (FISH) assays for NUTM1 and BRD4 rearrangements were negative, he was diagnosed based on diffusely positive NUT immunostaining and BRD4-NUTM1 on RNA sequencing. Since his initial presentation, he has undergone multiple surgical procedures and radiation therapy. His tumor has recurred twice, but he has survived for 129 months and is currently alive without disease. Long-term survival of patients with NUT carcinoma is incredibly unusual, especially in patients with tumors that exhibit a BRD4 rearrangement. False negative FISH is a pitfall in diagnosing NUT carcinoma; NUT immunostaining and RNA sequencing are more sensitive diagnostic methods.

Upregulation of Endothelial HLA Class II is a Marker of Antibody-Mediated Rejection in Heart Allograft Biopsies

In 2013, the International Society of Heart and Lung Transplant (ISHLT) introduced the working classification for pathologic changes associated with antibody-mediated rejection (AMR) of the heart allograft, known as pathologic AMR (pAMR). With 2 components associated with AMR, histopathologic changes) and immunopathologic markers, the proposed classification also suggests the use of class II HLA as a marker of endothelial integrity. It is known that during allograft rejection, endothelial cells are activated, therefore, we hypothesized that endothelial class II HLA rather than a marker of mere endothelial presence, is a marker of endothelial activation and becomes upregulated in AMR. Eight hundred thirty-eight heart allograft biopsies, collected from January 2016 to September 2018 at a single institution from patients with a current or recent diagnosis of AMR, were evaluated for both histopathologic and immunopathologic changes of AMR. Biopsies were labeled with immunofluorescence with antibodies against C4d and for immunohistochemistry with antibodies against C3d, CD68, and class II HLA. ISHLT criteria were used to classify the biopsies, and for class II HLA, both the percentage and the stain intensity were evaluated. Biopsies (74.8%) from our cohort showed either histopathologic pAMR-1, immunopathologic pAMR-1, or combined histopathologic and immunopathologic pAMR-2 evidence of AMR. Expression of endothelial HLA class II was significantly correlated with the diagnosis of AMR by percentage area (P < .0001) and intensity of staining (P < .0001). The diagnosis of AMR significantly correlated with moderate (+2) and strong (+3) staining intensity for class II HLA as follows: histopathologic and immunopathologic pAMR-2 with odds ratio (OR) = 28.3 (P < .0001);histopathologic pAMR-1 alone with OR = 22.7 (P < .0001); and immunopathologic pAMR-1 alone with OR = 32.6 (P < .0001). Interestingly, our study also suggested that the inclusion of C4d focally positive cases also significantly correlates with the diagnosis of AMR (P < .003). We confirmed our hypothesis that in heart allograft biopsies, there is a spectrum of both percentage and intensity of HLA class II expression due to endothelial activation, and that class II HLA by immunohistochemistry is a marker significantly correlated with the diagnosis of AMR. In addition, the group of focally positive C4d biopsies (10%-50%) should be considered positive for the immunopathologic component of the 2013 ISHLT classification, as this group of biopsies also correlated with the diagnosis of AMR.

Mammary Paget’s Disease of the Male Breast: A Rare Case With an Unusual Immunohistochemical Profile

Mammary Paget’s disease is rare and comprises about 0.62% of all breast cancer cases, only 1.65% of which occur in male patients. This case report involves a 76-year-old man who presented to his primary care physician with an itching, scaly, unilateral lesion involving the nipple skin. He underwent wide local excision of the lesion for a diagnosis of Bowen’s disease (squamous cell carcinoma in situ). Histologic examination of the specimen revealed mammary Paget’s disease with ductal carcinoma in situ in the underlying breast tissue. A panel of immunohistochemical stains revealed the Paget cells to be positive for cytokeratin 7, MUC1, GATA3, and androgen receptor and negative for cytokeratins 5/6, p63, SOX10, and MART-1/Melan-A. Paget cells were also negative for estrogen receptor and progesterone receptor, and positive for HER2/neu. However, the underlying ductal carcinoma in situ was positive for both estrogen receptor and progesterone receptor and negative for HER2/neu. This discordance, supported by the current literature, suggests an alternative etiology for Paget’s disease in certain cases that cannot be explained by the well-established epidermotropic and transformative theories of Paget’s disease evolution.

Interobserver agreement of an electronic von Frey device for measuring mechanical sensory thresholds in normal dogs

Electronic von Frey Aesthesiometry (VFA) has been previously reported as a useful method of mechanical quantitative sensory testing (QST) for evaluating neuropathic pain in dogs. Intraobserver agreement has been shown to be good to excellent; however, interobserver agreement has not been evaluated and is vital to the use of this technique in multicenter veterinary clinical trials in neuropathic pain. The goal of this study was to evaluate the interobserver agreement of sensory thresholds obtained using electronic VFA in a group of normal small breed dogs. Twenty healthy dogs (<20 kg) were recruited from the general practice population at the Ohio State University Veterinary Medical Center. Three clinically experienced yet QST novice evaluators used an electronic von Frey device to measure mechanical sensory threshold (ST) after a standardised training session conducted by an expert evaluator. Each dog was assessed by all three evaluators on the same day with both evaluator and limb test order randomised and testing sessions separated by 5 min. Mean ST values were averaged for all four limbs to produce a single value per dog for comparison between evaluators. Agreement between evaluators was determined using the intra-class correlation coefficient (ICC; two-way model for consistency, single measures). ICC across all three evaluators was 0.48, indicating moderate agreement. Moderate interobserver agreement is not sufficient to support the use of this technique in multi-center clinical trials, and our results underscore the importance of using a single evaluator for this QST technique until better agreement can be demonstrated.

Diagnosis-Related Group in Colon Surgery: Identifying Areas of Improvement to Drive High-Value Care

Diagnosis-related group (DRG) migration is defined as the reassignment of colectomy patients from DRG 331 to 330 based exclusively on postoperative complications. Strategic and comparative application of this metric has the potential to demonstrate baseline and excessive rates of complications related directly to patient care differences across institutions. The aim of this study was to report the variability of DRG migration across United States hospitals and its impact on overall cost and length of stay (LOS). This study investigated the variability of DRG migration rates across United States hospitals polling 5 per cent of the national Medicare data. The study end-points were total cost, LOS, and DRG migration rate. Hospitals were classified into tertiles for low (0.1–16.6%), moderate (16.7–23.0%), and high (23.1–83.3%) DRG migration rates. The study included 5120 patients from 615 hospitals. DRG migration rates for hospitals ranged from 0.1 per cent to 83.3 per cent, with 157 in the low, 183 in the moderate, and 364 in the high tertile. DRG migration resulted in a progressively increased LOS and hospital costs from the lowest to highest tertile. Several diagnoses were identified which are suggestive of failure to integrate evidence-based processes of care across the tertiles. The data confirm a wide variation in DRG migration rates from DRG 331 to 330 based only on postoperative complications. These ranges allow for the potential definition of both best practice, and opportunities for quality improvement with respect to postoperative complications, identification of hospital outliers, and the economics of care as part of a value-based care program.

The effect of malondialdehyde is modified by simian virus 40 transformation in human lung fibroblast cells

The effects of malondialdehyde (MDA), a product of oxidative stress, on normal lung fibroblast cells (MRC5) and transformed cells (MRC5 SV2) showed differing responses between the two cell lines. MRC5 cells showed lower viability at low MDA concentrations (<250 μM) but had better viability at higher concentrations than the transformed cells. Both cell lines showed an increase in the number of micronuclei, nuclear size and a relocation of p53 to the nucleus with increasing MDA. The expression of p53 was higher in the MRC5 cells at 24 h; 2-8 fold induction vs 1-2.5 fold in the MRC5 SV2 cells, but reduced to almost zero at 48 h in the MRC5 cells. Mutation sequencing of the PCR products of a 689 bp region (residues 4640-5328) of the TP53 gene revealed MRC5 had more mutations than MRC5 SV2 cells (n = 21 and 11 respectively) and that they were predominantly insertions (MRC5 81%, MRC5 SV2 100%). A common mutation was observed in both cell lines; a G insertion at residue 4724 (n = 7) which could prove to be a mutational hotspot. These results indicate that the transformed cells are slower to respond to oxidative stress and/or mutagenic compounds. The mutation spectrum of predominantly frameshift mutations (insertions) suggests that oxidative stress plays a minimal role in smoking related lung cancer, but could be of greater importance to other lung diseases and cancer caused by exposures such as passive smokers, passive vapers and atmospheric pollutants.

Diagnosis-Related Group in Colon Surgery: Identifying Areas of Improvement to Drive High-Value Care

Diagnosis-related group (DRG) migration is defined as the reassignment of colectomy patients from DRG 331 to 330 based exclusively on postoperative complications. Strategic and comparative application of this metric has the potential to demonstrate baseline and excessive rates of complications related directly to patient care differences across institutions. The aim of this study was to report the variability of DRG migration across United States hospitals and its impact on overall cost and length of stay (LOS). This study investigated the variability of DRG migration rates across United States hospitals polling 5 per cent of the national Medicare data. The study endpoints were total cost, LOS, and DRG migration rate. Hospitals were classified into tertiles for low (0.1-16.6%), moderate (16.7-23.0%), and high (23.1-83.3%) DRG migration rates. The study included 5120 patients from 615 hospitals. DRG migration rates for hospitals ranged from 0.1 per cent to 83.3 per cent, with 157 in the low, 183 in the moderate, and 364 in the high tertile. DRG migration resulted in a progressively increased LOS and hospital costs from the lowest to highest tertile. Several diagnoses were identified which are suggestive of failure to integrate evidence-based processes of care across the tertiles. The data confirm a wide variation in DRG migration rates from DRG 331 to 330 based only on postoperative complications. These ranges allow for the potential definition of both best practice, and opportunities for quality improvement with respect to postoperative complications, identification of hospital outliers, and the economics of care as part of a value-based care program.

Three-year Results of a Pilot Program in Early Liver Transplantation for Severe Alcoholic Hepatitis

OBJECTIVE

To examine our pilot to transplant selected patients with acute alcoholic hepatitis, initiated in October 2012.

BACKGROUND

Six months of alcohol abstinence is typically required before liver transplant. A Franco-Belgian protocol showed that early transplant in severe alcoholic hepatitis could improve survival with low incidence of alcohol relapse. Application of this controversial indication is growing despite unclear generalizability.

METHODS

Data was collected on all patients with alcohol-related liver disease since initiation of the pilot through June 2015. Patients were stratified into two groups: severe alcoholic hepatitis as first liver decompensation (Group 1), alcoholic cirrhosis with ≥6 months abstinence (Group 2). Alcohol relapse was defined as any evidence of alcohol consumption after transplant, which was assessed for harmful patterns of binge or frequent drinking.

RESULTS

Forty-three patients underwent liver transplant, including 17 patients in Group 1. Six-month survival was 100% versus 89% for Groups 1 and 2, respectively (P = 0.27). Alcohol relapse was similar in Group 1 versus Group 2: 23.5% versus 29.2% (P > 0.99). Harmful drinking was higher in Group 1 versus Group 2, despite lack of statistical significance: 23.5% versus 11.5% (P = 0.42).

CONCLUSIONS

In this pilot with carefully selected patients, early liver transplant provided excellent short-term survival, and similar rates of alcohol relapse compared with patients with 6 months of abstinence. Harmful patterns of relapse remain challenging in this population, highlighting the need for validated models to predict alcohol relapse, and need for extreme caution in selecting patients for this exceptional indication. Larger prospective studies and longer follow up are necessary.

Clinical characteristics of canine fibrocartilaginous embolic myelopathy (FCE): a systematic review of 393 cases (1973-2013)

Fibrocartilaginous embolic myelopathy (FCE) is common in dogs; however, there is conflicting information in the veterinary literature regarding clinical characteristics and data on recovery in severe cases is sparse. A systematic review of canine FCE was performed to delineate the natural history of this disease. 322 previously reported cases and 71 previously unreported cases were identified for inclusion. Source publications were identified via PubMed central search and by references from review articles. Previously unreported cases were identified via computerised medical records search at two veterinary institutions. FCE was most common in middle-aged large breed dogs (30 per cent); however, the miniature schnauzer was the most frequently reported individual breed and small breeds comprised 24 per cent of all reported cases. The most common neuroanatomical localisation was a T3-L3 myelopathy (33.1 per cent). Prognosis for recovery of ambulation was good to excellent with 85 per cent of cases regaining the ability to walk unassisted, most within 3 weeks. Persistent neurological deficits were common in patients that recovered ambulation (49.1 per cent). When nociception was absent in the affected limbs at initial presentation, rate of recovery was lower (10 per cent); however, this data is likely biased by limited follow-up in more severe cases. Future prospective studies should evaluate prognosis for more severely affected patients.

Kinematic Magnetic Resonance Imaging for Evaluation of Disc-Associated Cervical Spondylomyelopathy in Doberman Pinschers

BACKGROUND

The dynamic component of disc-associated cervical spondylomyelopathy (DA-CSM) currently is evaluated using traction magnetic resonance imaging (MRI), which does not assess changes in flexion and extension of the cervical vertebral column. In humans with cervical spondylotic myelopathy, kinematic MRI is used to identify dynamic compressions.

HYPOTHESIS/OBJECTIVES

To evaluate the feasibility and utility of kMRI in Doberman Pinschers with DA-CSM using a novel positioning device. We hypothesized that kMRI would identify compressive lesions not observed with neutral positioning and change the dimensions of the spinal cord and cervical vertebral canal.

ANIMALS

Nine client-owned Doberman Pinschers with DA-CSM.

METHODS

Prospective study. After standard MR imaging of the cervical spine confirmed DA-CSM, dogs were placed on a positioning device to allow imaging in flexion and extension. Morphologic and morphometric assessments were compared between neutral, flexion, and extension images.

RESULTS

Flexion was associated with improvement or resolution of spinal cord compression in 4/9 patients, whereas extension caused worsening of compressions in 6/9 patients. Extension identified 6 new compressive lesions and was significantly associated with dorsal and ventral compression at C5-C6 (P = .021) and C6-C7 (P = .031). A significant decrease in spinal cord height occurred at C6-C7 from neutral to extension (P = .003) and in vertebral canal height at C5-C6 and C6-C7 from neutral to extension (P = .011 and .017, respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Our results suggest that kMRI is feasible and provides additional information beyond what is observed with neutral imaging, primarily when using extension views, in dogs with DA-CSM.

von Frey anesthesiometry to assess sensory impairment after acute spinal cord injury caused by thoracolumbar intervertebral disc extrusion in dogs

Sensory threshold (ST) was measured using an electric von Frey anesthesiometer (VFA) in all limbs of 20 normal dogs and 29 dogs with acute thoracolumbar spinal cord injury (SCI) caused by spontaneous intervertebral disc extrusion. ST values were measured at three separate time points in normal dogs and on days 3, 10 and 30 following decompressive surgery in dogs with SCI. ST values were compared between groups and correlated with locomotor recovery in SCI-affected dogs. ST values were significantly higher (consistent with hypoalgesia) in the pelvic limbs of SCI-affected dogs at day 3, day 10 and day 30 when compared to normal dogs (P <0.05), while no significant difference in thoracic limb ST values was observed between groups. A progressive decrease in pelvic limb ST values occurred in SCI-affected dogs over time, consistent with improvement toward normal sensation or development of allodynia. This finding correlated inversely with locomotor score at 3 and 10 days after surgery. A significant decline in ST values across testing sessions was observed for all limbs of normal and SCI-affected dogs and may be related to patient acclimation, operator training effect, or effect of analgesic medications. This study supports the feasibility of VFA to assess differences in ST between normal and SCI-affected dogs. However, future studies must focus on techniques to minimize or compensate for clinical, environmental and behavioral factors which may impact ST values in the clinical setting.

The Spinal Ependymal Layer in Health and Disease

Ependymal cells are epithelial support cells that line the central canal and ventricular cavities of the central nervous system, providing the interface between the cerebrospinal fluid and the parenchyma of the brain and spinal cord. The spinal ependymal layer (SEL) is composed of 3 main cell types: tanycytes, ependymocytes, and cerebrospinal fluid-contacting neurons. A fourth cell type, termed the supraependymal cell, is also occasionally described. Cells of the SEL show restricted proliferative capacity in health but display neural stem cell properties both in vitro and in vivo in various disease states. A growing body of literature is devoted to the regenerative roles of the SEL, particularly in the context of spinal cord injury, where mechanical damage to the spinal cord leads to a significant increase in SEL proliferation. SEL-derived cell progeny migrate to sites of injury within the injured spinal cord parenchyma and contribute primarily to glial scar formation. In additional to their role as endogenous neural stem cells, cells of the SEL may be an important source of cytokines and other cell signaling molecules, such as tumor necrosis factor, heat shock proteins, and various growth factors. The SEL has become of recent interest to neuroscience researchers because of its potential to participate in and respond to diseases affecting the spinal cord (eg, traumatic spinal cord injury) and neurodegenerative disease. The intimate association of the SEL with the cerebrospinal fluid makes intrathecal therapies a viable option, and recent studies highlight the potential promise of treatments that augment SEL responses to disease.

The Prediction Predicament: Rethinking Necrotizing Soft Tissue Infections Mortality

BACKGROUND

Our study sought to identify independent risk factors predisposing patients with necrotizing soft tissue infections (NSTIs) to mortality from among laboratory values, demographic data, and microbiologic findings in a small population. To this end, a retrospective review was conducted of the medical records of all patients with NSTI who had been treated at our institution from 2003 to 2012 (n=134).

METHODS

Baseline demographics and comorbidities, clinical and laboratory values, hospital course, and the microbiologic characteristics of surgical incision cultures were recorded. Each variable was tested for association with survival status and all associated variables with p<0.15 were included in a logistic regression model to seek factors associated independently with mortality.

RESULTS

Surprisingly, no demographic or pre-existing condition proved to be a predictor of mortality. Two laboratory values had an inverse correlation to mortality: High C-reactive protein (CRP) and highest recorded CRP. Of surgical incisions that grew bacteria in culture, 33.6% were polymicrobial. Mortality rates were highest with Enterococcus-containing polymicrobial infections (50%), followed by those containing Pseudomonas (40%), and Streptococcus spp. (27%). Understanding why so many studies across the literature, now including our own, find such disparate results for correlation of NSTI mortality with patient data may lie in the fundamentally dynamic nature of the organisms involved.

CONCLUSIONS

This study suggests that no single factor present on admission is a robust predictor of outcome; it is likely that survival in NSTI is predicated upon a complex interaction of multiple host and microbial factors that do not lend themselves to reduction into a simple formula. It is also abundantly clear that the well-established principles of NSTI surgery should continue to be followed in all cases, with an emphasis on early debridement, irrespective of apparent severity of initial presentation.

Spinal Cord Ependymal Responses to Naturally Occurring Traumatic Spinal Cord Injury in Dogs

The spinal cord ependymal layer (SEL) is a recent focus in spinal cord injury (SCI) research because of its potential to serve as a source of endogenous neural stem cells. Dogs are an important spontaneous model of SCI; however, there is a paucity of information available in the literature regarding the canine SEL. Here we describe the histologic appearance and immunohistochemical staining patterns of the SEL in normal dogs (n = 4) and dogs with acute SCI caused by intervertebral disk extrusion (n = 7). Immunohistochemical staining for PCNA, Ki-67, caspase 3, E-cadherin, GFAP, and vimentin was employed in both groups. Staining for Ki-67 was absent in the SEL of normal and SCI-affected dogs, indicating possible restricted proliferative capacity of the canine SEL acutely after SCI. GFAP-positive cells were increased after SCI at both at the lesion epicenter and at proximal spinal cord sites (P = .001 and P = .006, respectively), supporting the possibility of astrocytic differentiation within the SEL after SCI. Total E-cadherin staining did not differ between normal and SCI-affected dogs (P = .42 for lesion epicenter, P = .09 at proximal sites) and was restricted to the apical cell surface in normal dogs. After SCI, E-cadherin staining was membrane-circumferential and cytosolic in nature, indicating possible loss of cellular polarity after injury that could drive cell migration from the SEL to injury sites. Enhanced GFAP expression and changes in E-cadherin expression patterns support additional studies to evaluate the canine SEL as a source of endogenous neural precursors that may be modulated for future clinical interventions after SCI.

Visualizing domain wall and reverse domain superconductivity

In magnetically coupled, planar ferromagnet-superconductor (F/S) hybrid structures, magnetic domain walls can be used to spatially confine the superconductivity. In contrast to a superconductor in a uniform applied magnetic field, the nucleation of the superconducting order parameter in F/S structures is governed by the inhomogeneous magnetic field distribution. The interplay between the superconductivity localized at the domain walls and far from the walls leads to effects such as re-entrant superconductivity and reverse domain superconductivity with the critical temperature depending upon the location. Here we use scanning tunnelling spectroscopy to directly image the nucleation of superconductivity at the domain wall in F/S structures realized with Co-Pd multilayers and Pb thin films. Our results demonstrate that such F/S structures are attractive model systems that offer the possibility to control the strength and the location of the superconducting nucleus by applying an external magnetic field, potentially useful to guide vortices for computing application.

When superconductivity emerges in a thin superconductor grown on a ferromagnet, it does so in an array of interacting superconducting and normally conducting channels. Maria Iavarone and colleagues use scanning tunnelling microscopy to image how these channels form and interact.

Cytokine concentrations in the cerebrospinal fluid of great danes with cervical spondylomyelopathy

Background

Chronic inflammation is involved in the pathogenesis of human cervical spondylotic myelopathy and could also play a role in cervical spondylomyelopathy (CSM) in dogs.

Hypothesis/Objectives

That cerebrospinal fluid (CSF) cytokine concentrations would differ between clinically normal (control) and CSM‐affected Great Danes (GDs), with affected GDs showing higher levels of inflammatory cytokines, such as interleukin (IL)‐6 and monocyte chemoattractant protein‐1/chemokine ligand 2 (MCP‐1/CCL2).

Animals

Client‐owned GDs: 15 control, 15 CSM‐affected.

Methods

Prospective study. Dogs underwent cervical vertebral column magnetic resonance imaging and collection of CSF from the cerebellomedullary cistern. Cytokine concentrations were measured using a commercially available canine multiplex immunoassay. Cytokine concentrations were compared between groups. Associations with the administration of anti‐inflammatory medications, disease duration and severity, severity of spinal cord (SC) compression, and SC signal changes were investigated in affected GDs.

Results

Affected GDs had significantly lower MCP‐1/CCL2 (mean 138.03 pg/mL, 95% confidence interval [CI] = 114.85–161.20) than control GDs (212.89 pg/mL, 95% CI = 165.68–260.11, P = .028). In affected GDs, MCP‐1/CCL2 concentrations correlated inversely with the severity of SC compression. There were no associations with administration of anti‐inflammatory medications, disease duration, or disease severity. IL‐6 concentrations were significantly higher (2.20 pg/mL, 95% CI = 1.92–2.47, P < .001) in GDs with SC signal changes.

Conclusions and Clinical Importance

Lower MCP‐1/CCL2 in CSM‐affected GDs might compromise clearance of axonal and myelin debris, delay axon regeneration, and affect recovery. Higher IL‐6 in CSM‐affected GDs with SC signal changes suggests more severe inflammation in this group.

Using multi-frequency acoustic attenuation to monitor grain size and concentration of suspended sediment in rivers

Multi-frequency acoustic backscatter profiles recorded with side-looking acoustic Doppler current profilers are used to monitor the concentration and size of sedimentary particles suspended in fluvial environments. Data at 300, 600, and 1200 kHz are presented from the Isère River in France where the dominant particles in suspension are silt and clay sizes. The contribution of suspended sediment to the through-water attenuation was determined for three high concentration (> 100 mg/L) events and compared to theoretical values for spherical particles having size distributions that were measured by laser diffraction in water samples. Agreement was good for the 300 kHz data, but it worsened with increasing frequency. A method for the determination of grain size using multi-frequency attenuation data is presented considering models for spherical and oblate spheroidal particles. When the resulting size estimates are used to convert sediment attenuation to concentration, the spheroidal model provides the best agreement with optical estimates of concentration, but the aspect ratio and grain size that provide the best fit differ between events. The acoustic estimates of size were one-third the values from laser grain sizing. This agreement is encouraging considering optical and acoustical instruments measure different parameters.

An approach based on ultra-high pressure liquid chromatography-tandem mass spectrometry to quantify O6-methyl and O6-carboxymethylguanine DNA adducts in intestinal cell lines

O⁶-methylguanine (O⁶-MeG) and O⁶-carboxymethylguanine (O⁶-CMG) are characteristic promutagenic and toxic DNA adducts formed by nitrosated glycine derivates and N-nitrosopeptides. Since endogenous nitrosation has been hypothesised as a plausible origin for the association between red and processed meat intake and colorectal cancer, a highly sensitive, fast and specific quantitative assay is needed to correlate the dose of individual DNA adducts with the effects of food consumption and individual digestive and metabolic processes. An ultra-high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay for quantitation of O⁶-MeG and O⁶-CMG, using the deuterated analogues as internal standards (ISTD), was developed. Samples of calf thymus DNA containing O⁶-MeG and O⁶-CMG were purified by acid hydrolysis and solid phase extraction prior to quantification by UHPLC-MS/MS in the selected reaction monitoring mode. The method was successfully validated in terms of repeatability (RSD<10%), reproducibility (RSD<15%) and linearity (99.9%) by incubating 0.1mg calf thymus DNA with the known N-nitroso compound potassium diazoacetate (KDA). The limit of quantitation was 30 fmol mg⁻¹ DNA for O⁶-MeG or 1 adduct per 10⁸ nucleotides and 50 fmol mg⁻¹ DNA for O⁶-CMG or 1.7 adducts per 10⁸ nucleotides. Subsequently, the method was applied to human colon carcinoma cell lines, Caco-2 and HT-29, treated with KDA to illustrate its capability to quantify O⁶-MeG and O⁶-CMG DNA adducts using biological relevant models in vitro. This method will support further research to unravel the mechanistic basis of endogenous nitrosation processes upon consumption of red and processed meat products.

Maturity status in male child and adolescent athletes

AIM

Early-maturing individuals may be at an advantage in some sports. The purpose of this study was to compare maturity status between competitive male child (10-12 years old) and adolescent (14-16 years old) athletes and minimally-active, age-matched controls.

METHODS

In total, 224 males were included in the study. Children (n=115) included minimally-active boys (n=34), soccer players (n=26), gymnasts (n=25) and hockey players (n=30). Adolescents (n=109) included minimally-active adolescents (n=31), soccer players (n=30), gymnasts (n=17) and hockey players (n=31). Sexual maturity was assessed using secondary sex characteristics and salivary testosterone concentration (sT). Skeletal age was also assessed, using quantitative ultrasound (Sunlight BonAgeTM).

RESULTS

Within each age group, no differences were observed between sport groups in chronological age, sT or pubertal age. In children, hockey players were more skeletally mature (12.43±1.36 years) than all other groups (11.0±1.0; 11.6±1.4 and 11.7±1.4 years for soccer, gymnasts and controls, respectively). In adolescents, hockey players and gymnasts had higher skeletal maturity (16.8±1.5 and 16.9±1.6 years, respectively; P<0.05) than controls (15.99±1.13 years).

CONCLUSION

While sexual and hormonal maturity does not appear to differ between similar-aged athletes of different sports, the results suggest greater skeletal maturity in hockey players, even before puberty.

Indications of proton-dominated cosmic-ray composition above 1.6 EeV

We report studies of ultrahigh-energy cosmic-ray composition via analysis of depth of air shower maximum (X(max)), for air shower events collected by the High-Resolution Fly's Eye (HiRes) observatory. The HiRes data are consistent with a constant elongation rate d<X(max)>/d[log(E)] of 47.9+/-6.0(stat)+/-3.2(syst) g/cm2/decade for energies between 1.6 and 63 EeV, and are consistent with a predominantly protonic composition of cosmic rays when interpreted via the QGSJET01 and QGSJET-II high-energy hadronic interaction models. These measurements constrain models in which the galactic-to-extragalactic transition is the cause of the energy spectrum ankle at 4x10(18) eV.

Reproductive performance of beef heifers: effects of vulvo-vaginitis, Ureaplasma diversum and prebreeding antibiotic administration

A group of 450 heifers, 13 to 15 mo of age, were individually identified, vaccinated (IBR, PI(3), Leptospira, Campylobacter fetus), examined (body condition score, reproductive tract evaluation, assessment of vaginal lesions), and cultured for U. diversum . Heifers were randomly allocated to either a treated group given chlortetracycline (approximately 350 mg/hd/d for 30 d in a grain crumble) or a nontreated control group. Prebreeding, most heifers showed signs of vulvovaginitis, 44% cultured positive for U. diversum . Significant associations were found between the severity of vaginal lesions and ovarian activity (P < 0.05), and between BCS and ovarian activity (P < 0.02). The U. diversum vaginal culture (positive or negative) showed no significant association with BCS, severity of vaginal lesions, or ovarian activity (all were P > 0.5). At pregnancy examination (35 d following conclusion of a 61-d breeding season), treated compared with nontreated heifers showed 1) a slight but not significant (P > 0.25) decrease in vaginal colonization by U. diversum (46 to 34% and 41 to 37%, respectively); 2) an association between increased severity of vaginal lesions and increasing pregnancy rate, especially in treated heifers; and 3) an increased pregnancy rate (72 and 57%, respectively; P < 0.01). Prebreeding treatment with chlortetracycline appeared to improve pregnancy rates in beef heifers with endemic U. diversum infections, although the role of U. diversum in heifer fertility is still not clear.

First observation of the Greisen-Zatsepin-Kuzmin suppression

The High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called the GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement of the flux of ultrahigh energy cosmic rays shows a sharp suppression at an energy of 6 x 10(19) eV, consistent with the expected cutoff energy. We observe the ankle of the cosmic-ray energy spectrum as well, at an energy of 4 x 10(18) eV. We describe the experiment, data collection, and analysis and estimate the systematic uncertainties. The results are presented and the calculation of the statistical significance of our observation is described.

Photonic crystal laser with mode selective mirrors

The mini-stopband (MSB) of a W3 line-defect photonic crystal waveguide is used as a mirror for a GaAs based quantum-dot laser. Single mode, continuous-wave lasing is demonstrated for broad area lasers up to a current of 125 mA (2.7 x laser threshold), which demonstrates the high degree of mode selectivity of the MSB mirror. FDTD calculations indicate that optimisation of the mirror interface could lead to a further fourfold increase in reflectivity resulting in significantly reduced thresholds.

Identification of a high-affinity binding site involved in the transport of endocannabinoids

Phytocannabinoids, such as the principal bioactive component of marijuana, delta9-tetrahydrocannabinol, have been used for thousands of years for medical and recreational purposes. delta9-Tetrahydrocannabinol and endogenous cannabinoids (e.g., anandamide) initiate their agonist properties by stimulating the cannabinoid family of G protein-coupled receptors (CB1 and CB2). The biosynthesis and physiology of anandamide is well understood, but its mechanism of uptake (resulting in signal termination by fatty acid amide hydrolase) has been elusive. Mounting evidence points to the existence of a specific anandamide transport protein; however, no direct evidence for this protein has been provided. Here, we use a potent, competitive small molecule inhibitor of anandamide uptake (LY2318912, IC50 7.27 +/- 0.510 nM) to identify a high-affinity, saturable anandamide transporter binding site (LY2318912; K(d) = 7.62 +/- 1.18 nM, B(max) = 31.6 +/- 1.80 fmol/mg protein) that is distinct from fatty acid amide hydrolase. Systemic administration of the inhibitor into rodents elevates anandamide levels 5-fold in the brain and demonstrates efficacy in the formalin paw-licking model of persistent pain with no obvious adverse effects on motor function. Identification of the anandamide transporter binding site resolves a missing mechanistic link in endocannabinoid signaling, and in vivo results suggest that endocannabinoid transporter antagonists may provide a strategy for positive modulation of cannabinoid receptors.

Measurement of the flux of ultrahigh energy cosmic rays from monocular observations by the High Resolution Fly's Eye experiment

We have measured the cosmic ray spectrum above 10(17.2) eV using the two air-fluorescence detectors of the High Resolution Fly's Eye observatory operating in monocular mode. We describe the detector, phototube, and atmospheric calibrations, as well as the analysis techniques for the two detectors. We fit the spectrum to a model consisting of galactic and extragalactic sources.

Dietary intake, eating behavior, and physical activity-related determinants of high body mass index in rural communities in Wyoming, Montana, and Idaho

OBJECTIVE

To assess the relation between body mass index (BMI) levels and various lifestyle variables related to physical activity and specific characteristics of a healthy eating pattern, using baseline cross-sectional data from the Wellness IN the Rockies project.

SUBJECTS

A total of 928 males and 889 females, aged 18-99 y, recruited from six rural communities in Wyoming, Montana, and Idaho.

MEASUREMENTS

Using BMI as the criterion, overweight was defined as a BMI >or=25 kg/m(2) and obesity was defined as a BMI >or=30 kg/m(2). All participants in this study completed a questionnaire that elicited sociodemographic information, self-reported height and weight, and data related to specific dietary intakes, eating-related behaviors, and physical activity behaviors and perceptions.

RESULTS

Prevalence of overweight was 70% in men and 59% in women. Increased likelihood of overweight or obesity was associated with greater frequency of the following: drinking sweetened beverages such as soft drinks/soda pop, ordering supersized portions, eating while doing other activities, and watching television. Other predictors were lower frequency of participation in physical activity and the perception of not getting as much exercise as needed.

CONCLUSIONS

The increased probability of having a high BMI in individuals who more often eat while doing another activity appears to be a novel finding that will need to be substantiated by additional research. The finding that the vast majority of overweight and obese respondents believed that they do not get as much exercise as needed strengthens the assertion that finding ways to increase participation in physical activity should remain a high priority in obesity prevention and intervention efforts at the community and individual levels.

Brain expression of inducible cyclooxygenase 2 messenger RNA in rats undergoing cardiopulmonary bypass

BACKGROUND

We hypothesized that systemic proinflammatory cytokines or endotoxemia, or both, associated with cardiopulmonary bypass (CPB) would increase expression of inducible cyclooxygenase (COX-2) or inducible nitric oxide synthase (iNOS) messenger RNA (mRNA), or both, in brain.

METHODS

Isoflurane-anesthetized Sprague-Dawley rats were randomly selected for CPB (n = 6) or sham surgery (n = 6). All animals underwent tracheotomy and controlled ventilation, arterial and venous pressure monitoring, insertion of a jugular venous outflow catheter, insertion of a subclavian arterial inflow catheter, systemic anticoagulation (500 U/kg heparin) and, except during CPB, servoregulation of pericranial temperature at 37.5 degrees C. Animals selected for CPB underwent 1 h of CPB at 165 ml x kg(-1) x min(-1) (31.8 +/- 0.2 degrees C), whereas animals having sham surgery underwent no intervention during this interval. Thereafter, all animals were given protamine and remained anesthetized for 4 more h. Brain and liver COX-2 and iNOS mRNA expression were determined by a ribonuclease protection assay with ribosomal L32 mRNA as a loading control. Arterial blood was analyzed for interleukin 1beta, interleukin 6, and endotoxin concentrations.

RESULTS

Endotoxin concentrations did not increase above baseline values in either group. At 4 h after the CPB interval, interleukin 6 concentrations were significantly greater in CPB animals (101 +/- 45 pg/ml) versus sham animals (44 +/- 17 pg/ml) (P = 0.025). Brain COX-2 expression was significantly greater in CPB animals (0.36 +/- 0.11) versus shams (0.19 +/- 0.08) (P = 0.013). Brain COX-2 expression correlated with interleukin 6 concentration 4 h after CPB (r = 0.91; P = 5 x 10(-5)). In brain, iNOS mRNA was not detected in any animal. Cardiopulmonary bypass animals had only trace COX-2 and iNOS mRNA induction in liver.

CONCLUSIONS

Cardiopulmonary bypass was associated with increased systemic interleukin 6 concentrations and increased brain COX-2 expression.

Interobserver variability associated with the MIB-1 labeling index: high levels suggest limited prognostic usefulness for patients with primary brain tumors

BACKGROUND

The use of the MIB-1 labeling index (LI) as a potential prognostic marker for patients with primary brain tumors is controversial. Many studies advocating its prognostic usefulness have suggested discrete MIB-1 LI cut-off values, above which patients have significantly worse outcomes. However, interobserver variability associated previously with MIB-1 LI calculation has not been reported despite the fact that the degree of interobserver variability impacts the clinical usefulness of such cut-off values.

METHODS

MIB-1 LIs were calculated independently using a standardized protocol by six pathologist observers for 50 astrocytic gliomas of varying grades. The level of interobserver agreement was determined by calculating kappa statistics for pairwise pathologist comparisons using MIB-1 LI cut-off values of 2.5%, 5.0%, 8.0%, 11.0%, and 15.0%. Spearman rank correlation coefficients were used to assess the pairwise associations between observer MIB-1 LIs.

RESULTS

Although there was general agreement among pathologists regarding whether an MIB-1 LI for a given astroglial tumor was low, moderate, or high based on the analysis of correlation, a high level of interobserver variability was associated with the determination of specific MIB-1 LIs. The highest level of agreement occurred using a cut-off value of 5.0%, with pairwise kappa statistics for this value ranging from 0.52 to 0.80.

CONCLUSIONS

The high level of interobserver variability suggests that proposed discrete MIB-1 LI prognostic cut-off values most likely are not useful clinically for predicting outcome for individual patients with primary brain tumors. Further prospective studies are needed investigating the prognostic usefulness of MIB-1 LI ranges that optimize interobserver agreement.

The structure of truncated recombinant human bile salt-stimulated lipase reveals bile salt-independent conformational flexibility at the active-site loop and provides insights into heparin binding

Human bile salt-stimulated lipase (BSSL), which is secreted from the pancreas into the digestive tract and from the lactating mammary gland into human milk, is important for the effective absorption of dietary lipids. The dependence of BSSL on bile acids for activity with water-insoluble substrates differentiates it from other lipases. We have determined the crystal structure of a truncated variant of human BSSL (residues 1-5.8) and refined it at 2.60 A resolution, to an R-factor of 0.238 and R(free) of 0.275. This variant lacks the C-terminal alpha-helix and tandem C-terminal repeat region of native BSSL, but retains full catalytic activity. A short loop (residues 115-126) capable of occluding the active-site (the active site loop) is highly mobile and exists in two conformations, the most predominant of which leaves the active-site open for interactions with substrate. The bile salt analogue 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonic acid (CHAPS) was present in the crystallisation medium, but was not observed bound to the enzyme. However, the structure reveals a sulfonate group from the buffer piperizine ethane sulfonic acid (PIPES), making interactions with Arg63 and His115. His115 is part of the active-site loop, indicating that the loop could participate in the binding of a sulphate group from either the glycosaminoglycan heparin (known to bind BSSL) or a bile acid such as deoxycholate. Opening of the 115-126 active-site loop may be cooperatively linked to a sulphate anion binding at this site. The helix bundle domain of BSSL (residues 319-398) exhibits weak electron density and high temperature factors, indicating considerable structural mobility. This domain contains an unusual Asp:Glu pair buried in a hydrophobic pocket between helices alpha(H) and alpha(K) that may be functionally important. We have also solved the structure of full-length glycosylated human BSSL at 4.1 A resolution, using the refined coordinates of the truncated molecule as a search model. This structure reveals the position of the C-terminal helix, missing in the truncated variant, and also shows the active-site loop to be in a closed conformation.

Optic neuritis: a novel presentation of Schilder's disease

The clinical features of a 7-year-old girl who presented with unilateral optic neuritis are presented. Magnetic resonance imaging (MRI) showed lesions in the affected optic nerve and the centrum semiovale bilaterally. Biopsy of one of the cerebral lesions was consistent with a diagnosis of Schilder's disease. Visual acuity returned to normal, and the demyelinating MRI lesions improved markedly with corticosteroid treatment. Optic neuritis is a novel mode of presentation in Schilder's disease.

Docosahexaenoic acid synthesis from n-3 polyunsaturated fatty acids in differentiated rat brain astrocytes

DHA, the main n-3 PUFA in the brain, is synthesized from n-3 PUFA precursors by astrocytes. To assess the potential of this process to supply DHA for the brain, we investigated whether the synthesis in astrocytes is dependent on DHA availability. Rat brain astrocytes differentiated with dibutyryl cAMP and incubated in media containing 10% fetal bovine serum synthesized DHA from alpha-linolenic acid ([1-(14)C]18:3n-3), docosapentaenoic acid ([3-(14)C]22:5n-3), tetracosapentaenoic acid ([3-(14)C]24:5n-3), and tetracosahexaenoic acid ([3-(14)C]24:6n-3). When DHA was added to media containing a 5 microM concentration of these (14)C-labeled n-3 PUFA, radiolabeled DHA synthesis was reduced but not completely suppressed even when the DHA concentration was increased to 15 microM. Radiolabeled DHA synthesis also was reduced but not completely suppressed when the astrocytes were treated with 30 microM DHA for 24 h before incubation with 5 microM [1-(14)C]18:3n-3.These findings indicate that although the DHA synthesis in astrocytes is dependent on DHA availability, some synthesis continues even when the cells have access to substantial amounts of DHA. This suggests that DHA synthesis from n-3 PUFA precursors is a constitutive process in the brain and, therefore, is likely to have an essential function.

CpG DNA induces cyclooxygenase-2 expression and prostaglandin production

Unmethylated CpG motifs found in bacterial DNA are potent activators of the innate and acquired immune systems, and rapidly induce the production of proinflammatory cytokines. We hypothesized that CpG DNA may also elicit the production of prostaglandins (PG), which are central lipid mediators of the immune and inflammatory response. To test our hypothesis, we stimulated murine spleen cells and RAW 264.7 murine macrophage cells with CpG DNA and assessed the effects on the PG synthesis pathway. Compared to control, DNA-containing CpG motifs induced >5-fold increase in PGE (2) production and rapidly up-regulated cyclooxygenase-2 (COX-2) at both the mRNA and protein level. CpG DNA was an extremely strong inducer of COX-2 as concentrations as low as 3 ng/ml induced COX-2 protein expression. The CpG DNA-induced PGE (2) down-regulated the immune response elicited by CpG. Blockade of PGE (2) production with selective COX-2 inhibitors or neutralizing anti-PGE (2) antibody markedly enhanced IFN-gamma secretion in vitro from CpG DNA-stimulated spleen cells. Moreover, selective COX-2 inhibition increased CpG DNA-induced IFN-gamma secretion in vivo. Inhibition of COX-2 also increased CpG DNA-induced lytic activity of NK cells. Taken together, these data indicate that DNA containing CpG motifs is a potent inducer of COX-2 and PGE (2) production. CpG-induced PG may subsequently down-regulate the immune and inflammatory responses elicited by the CpG DNA.

COX-2-dependent delayed dilatation of cerebral arterioles in response to bradykinin

Bradykinin (BK) is released in the brain during injury and inflammation. Activation of endothelial BK receptors produces acute dilatation of cerebral arterioles that is mediated by reactive oxygen species (ROS). ROS can also modulate gene expression, including expression of the inducible isoform of cyclooxygenase (COX-2). We hypothesized that exposure of the brain to BK would produce acute dilatation, which would be followed by a delayed dilatation mediated by COX-2. To test this hypothesis in anesthetized rats, BK was placed twice in cranial windows for 7 min, after which the windows were flushed to remove residual BK. The two BK exposures were separated by 30 min. Each BK exposure produced acute dilatation of cerebral arterioles, after which diameter rapidly returned to baseline. Over the subsequent 4.5 h after the second BK exposure, arterioles dilated 48 +/- 8%. Treatment of the cranial window with NS-398, a selective COX-2 inhibitor, or dexamethasone, significantly attenuated the delayed dilatation. Aminoguanidine, a selective inhibitor of inducible nitric oxide synthase, did not alter the delayed dilatation. Cotreatment of cranial windows with BK, superoxide dismutase, and catalase also prevented the delayed dilatation. In separate experiments, exposure of the cortical surface to BK upregulated leptomeningeal expression of COX-2 mRNA. Our results suggest that acute, time-limited exposure of the brain to BK produces delayed dilatation of cerebral arterioles dependent on expression and activity of COX-2.

Brain uptake and utilization of fatty acids: recommendations for future research

A primary goal of the international workshop "Brain Uptake and Utilization of Fatty Acids" was to identify research areas that would benefit from further investigation. The major themes for future research are presented below: (1) Elucidating the role of the developing and mature cerebrovascular endothelium (CVE) in the uptake of fatty acids (FA) into the brain. (2) Clarifying the role of diffusion and receptor-mediated uptake of FAs by various brain cell membranes and protein-mediated shuttling of FAs between the CVE and various brain cells and tissues. (3) Illuminating the mechanisms of intermediate metabolism and the roles of polyunsaturated fatty acids (PUFA) in astrocytes, neurons and oligodendrocytes. Of special interest are the long-chain omega-3 PUFA and their derivatives, such as lipoproteins, phospholipids and plasmalogens, that have been associated with various disease states (such as those listed in [5], below). (4) Elucidating the role of gene expression on long-chain omega-3 PUFA incorporation in membranes and the regulatory role these and other PUFA have on gene expression in the brain. (5) Elucidating the recently identified roles of long-chain omega-3 PUFA in mood disorders, schizophrenia, stroke, peroxisomal biogenesis disorders, Huntington's disease, other neurodegenerative disorders and disorders of oxidative stress. (6) Undertaking placebo-controlled clinical trials to assess the therapeutic potential of omega-3 PUFA in the above disorders. (7) Developing new, and utilizing existing animal models in the above studies. (8) Developing noninvasive imaging and tagging methods for quantifying the migration and distribution of PUFA and their derivatives in the brain. (9) Applying multi-disciplinary collaborations among biophysicists, physiologists and molecular biologists to the resolution of the above.

Brain uptake and utilization of fatty acids: applications to peroxisomal biogenesis diseases

The brain is rich in diverse fatty acids saturated, monounsaturated and polyunsaturated fatty acids with chain lengths ranging from less than 16 to more than 24 carbons that make up the complex lipids present in this organ. While some fatty acids are derived from endogenous synthesis, others must come from exogenous sources. The mechanism(s) by which fatty acids enter cells has been the subject of much debate. While some investigators argue for a protein-mediated process, others suggest that simple diffusion is sufficient. In the brain, uptake is further complicated by the presence of the blood-brain barrier. Brain fatty acid homeostasis is disturbed in many human disorders, as typified by the peroxisomal biogenesis diseases. A workshop designed to bring together researchers from varied backgrounds to discuss these issues in an open forum was held in March, 2000. In addition to assessing the current state of knowledge, areas requiring additional investigation were identified and recommendations for future research were made. A brief overview of the invited talks is presented here.

Polyunsaturated fatty acid synthesis and release by brain-derived cells in vitro

The brain is more highly enriched than most other tissues in long-chain polyunsaturated fatty acids (PUFA), particularly docosahexaenoic acid (DHA). In vitro studies of PUFA synthesis and release utilizing cell cultures of astrocytes, neurons, and cerebral microvascular endothelium have contributed significantly to our understanding of mechanisms potentially involved in the accretion of PUFA in brain. Both cerebral endothelium and astrocytes avidly elongate and desaturate precursors of the long-chain PUFAs when grown individually or in various co-culture combinations. The products, such as arachidonic acid (AA) and DHA, are released from the cells. In contrast, neurons appear unable to carry out fatty acid desaturation and thus are dependent upon preformed long-chain PUFA. Indeed, neurons co-cultured with astrocytes accumlate docosahexaenoate synthesized by the glial cells. Cerebral endothelial cultures are additionally capable of enriching the basolateral compartment (analogous to the brain extracellular space) with n-3 PUFA when grown in a membrane/chamber apparatus. The enrichment of this compartment with DHA is increased when cerebral endothelium is co-cultured with astrocytes. These data suggest that endothelial cells and astrocytes cooperate in the local synthesis and release of PUFA, collectively maintaining a brain environment enriched in long-chain PUFA.

Effect of cessation and resumption of static hamstring muscle stretching on joint range of motion

STUDY DESIGN

Single group repeated measures.

OBJECTIVES

To determine the effects of cessation and resumption of a hamstring muscle stretching protocol on knee range of motion (ROM).

BACKGROUND

It is generally accepted that stretching exercises result in an increase in ROM. The ability to maintain ROM once stretching has ceased and the ability to regain ROM after resumption of the stretching exercise is not well-known.

METHODS AND MEASURES

Evaluated the effect of 6 weeks of static hamstring stretching, 4 weeks with cessation from stretching, and 6 weeks with resumption of stretching on knee ROM in 18 inactive college students (12 men, 6 women, mean age 21.0 years). The hamstring stretching consisted of 2 30-second stretches per day, 5 days per week. Knee ROM was measured before and after each of the above phases with an active knee extension test.

RESULTS

Mean knee ROM increased after the initial stretching period (143+/-11 to 152+/-9 degrees), decreased to baseline following the cessation period (145+/-8 degrees) and again increased following the resumption of stretching but was not different from the initial gains (154+/-10 degrees). Unlike the stretch limb, the control limb ROM did not change over the 4 measurement times.

CONCLUSIONS

There was no retention of knee ROM 4 weeks following a 6-week stretching protocol and a subsequent stretching period did not enhance the gain of knee ROM over the initial stretching period.

Il-10 is a central regulator of cyclooxygenase-2 expression and prostaglandin production

IL-10 is a potent anti-inflammatory and immune regulatory cytokine. IL-10(-/-) mice produce exaggerated amounts of inflammatory cytokines when stimulated with LPS, indicating that endogenous IL-10 is a central regulator of inflammatory cytokine production in vivo. PGs are lipid mediators that are also produced in large amounts during the inflammatory response. To study the role of IL-10 in the regulation of PG production during the acute inflammatory response, we evaluated LPS-induced cyclooxygenase (COX) expression and PG production in wild-type (wt) and IL-10(-/-) mice. LPS-induced PGE(2) production from IL-10(-/-) spleen cells was 5.6-fold greater than that from wt spleen cells. LPS stimulation resulted in the induction of COX-2 mRNA and protein in both wt and IL-10(-/-) spleen cells; however, the magnitude of increase in COX-2 mRNA was 5.5-fold greater in IL-10(-/-) mice as compared with wt mice. COX-1 protein levels were not affected by LPS stimulation in either wt or IL-10(-/-) mice. Neutralization of IFN-gamma, TNF-alpha, or IL-12 markedly decreased the induction of COX-2 in IL-10(-/-) spleen cells, suggesting that increased inflammatory cytokine production mediates much of the COX-2 induction in IL-10(-/-) mice. Treatment of IL-10(-/-) mice with low doses of LPS resulted in a marked induction of COX-2 mRNA in the spleen, whereas wt mice had minimal expression of COX-2 mRNA. These findings indicate that, in addition to IL-10's central role in the regulation of inflammatory cytokines, endogenous IL-10 is an important regulator of PG production in the response to LPS.