Metabolic Correlates In Spinal Cord Compression Measured By Magnetic Resonance Spectroscopy In The Motor And Sensory Cortices, Sandy Goncalves

Electronic Thesis and Dissertation Repository

Surgical outcome for patients suffering from cervical myelopathy (CM) is unpredictable with varying motor and sensory symptom recovery. Previous in-vivo magnetic resonance spectroscopy (MRS) studies of patients surgically treated for CM have demonstrated decreased N-acetylaspartate (NAA)/creatine levels in the motor cortex indicating reduced neuronal function. The goal of this thesis was to determine whether absolute NAA changes in the motor and sensory cortices mirror the pattern of motor and sensory functional change observed in patients post surgical treatment.

MRS data were acquired on a 3.0 Tesla Siemens MRI along with clinical outcome measures at baseline, 6-weeks and 6-months post-surgery. …

Mouse Models Of Intervertebral Disc Development, Degeneration And Mechanical Loading, Matthew R. Mccann

Electronic Thesis and Dissertation Repository

Intervertebral disc (IVD) degeneration is a complex and multi-factorial process that is influenced by aging, genetic predispositions and environmental influences, such as altered mechanical loading. While recent studies have begun to characterize changes in the IVD associated with degeneration, the underlying etiology remains elusive. It is thought that the loss of notochord cells from the nucleus pulposus (NP) is one initiating factor contributing to the cascade of disc degeneration. However, questions remain about the function of notochord cells within the disc, including their capacity as tissue specific progenitor cells for the nucleus pulposus. We have demonstrated, with the use of …

Modulation Of The Cardiomyocyte Hypertrophic Responses To Endothelin-1 By Adipocytes, Suresh Chandra Bairwa

Electronic Thesis and Dissertation Repository

Leptin and adiponectin are the adipokines that are shown to exert pro-hypertrophic and anti-hypertrophic effects respectively, in cardiomyocytes. We sought to determine the direct interaction between the adipocytes and cardiomyocytes during endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy and determine the role of leptin and adiponectin.

The adipose tissue conditioned medium (ACM) inhibited the ET-1-induced hypertrophy in a concentration-dependent manner and this anti-hypertrophic effect was more potent or reversed in the presence of leptin receptor antagonist (LRA; 0.1 nM) or adiponectin receptor-1 antibody (ARA; 100 ng/mL), respectively. ACM from heart failure rats induced by coronary artery ligation or obese rats did not mitigate …

Registration Of In-Vivo To Ex-Vivo Mri Of Surgically Resected Specimens: A Pipeline For Histology To In-Vivo Registration., Maged Goubran, Sandrine De Ribaupierre, Robert R Hammond, Catherine Currie, Jorge G Burneo, Andrew G Parrent, Terry M Peters, Ali R Khan

Medical Biophysics Publications

BACKGROUND: Advances in MRI have the potential to improve surgical treatment of epilepsy through improved identification and delineation of lesions. However, validation is currently needed to investigate histopathological correlates of these new imaging techniques. The purpose of this work is to develop and evaluate a protocol for deformable image registration of in-vivo to ex-vivo resected brain specimen MRI. This protocol, in conjunction with our previous work on ex-vivo to histology registration, completes a registration pipeline for histology to in-vivo MRI, enabling voxel-based validation of novel and existing MRI techniques with histopathology.

NEW METHOD: A combination of image-based and landmark-based 3D …

Functional Lung Avoidance For Individualized Radiotherapy (Flair): Study Protocol For A Randomized, Double-Blind Clinical Trial., Douglas A Hoover, Dante Pi Capaldi, Khadija Sheikh, David A Palma, George B Rodrigues, A Rashid Dar, Edward Yu, Brian Dingle, Mark Landis, Walter Kocha, Michael Sanatani, Mark Vincent, Jawaid Younus, Sara Kuruvilla, Stewart Gaede, Grace Parraga, Brian P Yaremko

Medical Biophysics Publications

BACKGROUND: Although radiotherapy is a key component of curative-intent treatment for locally advanced, unresectable non-small cell lung cancer (NSCLC), it can be associated with substantial pulmonary toxicity in some patients. Current radiotherapy planning techniques aim to minimize the radiation dose to the lungs, without accounting for regional variations in lung function. Many patients, particularly smokers, can have substantial regional differences in pulmonary ventilation patterns, and it has been hypothesized that preferential avoidance of functional lung during radiotherapy may reduce toxicity. Although several investigators have shown that functional lung can be identified using advanced imaging techniques and/or demonstrated the feasibility and …

The Relationship Of Plantar Sensation With Standing Balance And Gait Post-Stroke, Stephen Parsons

Electronic Thesis and Dissertation Repository

Gait and balance dysfunction after stroke limit independence and quality of life. Numerous contributing factors have been investigated but the role of sensation deficits has received little attention. This thesis investigated the relationship between plantar cutaneous sensation and 1) standing balance, 2) gait, and 3) use of vision to compensate for sensory loss with a secondary analysis of data from individuals with subacute stroke. Associations between standing balance, gait and sensation were investigated with Spearman correlations. Individuals classified as impaired or intact sensation were compared on gait and standing balance measures. This thesis found plantar sensation is related to standing …

Free-Breathing Pulmonary (1)H And Hyperpolarized (3)He Mri: Comparison In Copd And Bronchiectasis., Dante P I Capaldi, Khadija Sheikh, Fumin Guo, Sarah Svenningsen, Roya Etemad-Rezai, Harvey O Coxson, Jonathon A Leipsic, David G Mccormack, Grace Parraga

Medical Biophysics Publications

RATIONALE AND OBJECTIVES: In this proof-of-concept demonstration, we aimed to quantitatively and qualitatively compare pulmonary ventilation abnormalities derived from Fourier decomposition of free-breathing (1)H magnetic resonance imaging (FDMRI) to hyperpolarized (3)He MRI in subjects with chronic obstructive pulmonary disease (COPD) and bronchiectasis.

MATERIALS AND METHODS: All subjects provided written informed consent to a protocol approved by a local research ethics board and Health, Canada, and they underwent MRI, computed tomography (CT), spirometry, and plethysmography during a single 2-hour visit. Semiautomated segmentation was used to generate ventilation defect measurements derived from FDMRI and (3)He MRI, and these were compared using analysis …

Regulation Of Crfr1 And 5-Ht2ar By Pdz Domain-Containing Proteins Sap97 And Psd-95, Henry A. Dunn

Electronic Thesis and Dissertation Repository

Previous studies identified a crosstalk mechanism whereby CRFR1 sensitized 5-HT_2AR-mediated signaling via interactions with PDZ domain-containing proteins: a mechanism that may underlie stress-induced anxiety and depression. This prompted an investigation into uncovering which PDZ domain-containing proteins could regulate the crosstalk between these two receptors, and how they could be regulated individually. In the current studies, a subset of PDZ domain-containing proteins were identified that may interact with CRFR1 and 5-HT_2AR. The focus narrowed to two candidates previously implicated in psychiatric disease: SAP97 and PSD-95. We confirmed SAP97 and PSD-95 as interacting partners of CRFR1 in adult …

Anatomical, Functional And Metabolic Imaging Of Radiation-Induced Lung Injury Using Hyperpolarized Mri., Giles Santyr, Matthew Fox, Kundan Thind, Elaine Hegarty, Alexei Ouriadov, Michael Jensen, Timothy J Scholl, Jacob Van Dyk, Eugene Wong

Medical Biophysics Publications

MRI of hyperpolarized (129)Xe gas and (13)C-enriched substrates (e.g. pyruvate) presents an unprecedented opportunity to map anatomical, functional and metabolic changes associated with lung injury. In particular, inhaled hyperpolarized (129)Xe gas is exquisitely sensitive to changes in alveolar microanatomy and function accompanying lung inflammation through decreases in the apparent diffusion coefficient (ADC) of alveolar gas and increases in the transfer time (T(tr)) of xenon exchange from the gas and into the dissolved phase in the lung. Furthermore, metabolic changes associated with hypoxia arising from lung injury may be reflected by increases in lactate-to-pyruvate signal ratio obtained by magnetic resonance spectroscopic …

Vitamin D And White Matter Abnormalities In Older Adults: A Cross-Sectional Neuroimaging Study., C Annweiler, T Annweiler, R Bartha, F R Herrmann, R Camicioli, O Beauchet

Medical Biophysics Publications

BACKGROUND AND PURPOSE: Morphological brain changes related to hypovitaminosis D have been poorly studied. In particular, the age-related decrease in vitamin D concentrations may explain the onset of white matter abnormalities (WMA) in older adults. Our objectives were (i) to investigate whether there was an association between serum 25-hydroxyvitamin D (25OHD) concentration and the grade of WMA in older adults and (ii) to determine whether the location of WMA was associated with 25OHD concentration.

METHODS: One hundred and thirty-three Caucasian older community-dwellers with no clinical hydrocephalus (mean 71.6 ± 5.6 years; 43.6% female) received a blood test and a magnetic …

Pancreatic Beta Cell Plasticity And Involvement Of Insulin-Expressing Progenitor Cells, Christine A. Beamish

Electronic Thesis and Dissertation Repository

Islet transplants have been successfully used as treatment for diabetes, but are limited by shortages of cadaveric insulin-producing β-cells. An alternate source may be the dedifferentiation, expansion, and subsequent redifferentiation of pancreatic islets or β-cells using in vitro techniques prior to transplant. Based on protocols which described the dedifferentiation of human islets to ductal-like cells, we hypothesized that neonatal mouse islets could be similarly dedifferentiated in vitro. Dedifferentiation techniques produced significant duct-like cells, but redifferentiation to insulin-expressing cells was limited. RIPCre;Z/AP+/+ mice were consequently utilized to lineage trace β-cell fate during culture by a human placental alkaline phosphatase (HPAP) reporter. …

P-I-N Heterojunctions With Bifeo3 Perovskite Nanoparticles And P- And N-Type Oxides: Photovoltaic Properties., Soumyo Chatterjee, Abhijit Bera, Amlan J Pal

Medical Biophysics Publications

We formed p-i-n heterojunctions based on a thin film of BiFeO3 nanoparticles. The perovskite acting as an intrinsic semiconductor was sandwiched between a p-type and an n-type oxide semiconductor as hole- and electron-collecting layer, respectively, making the heterojunction act as an all-inorganic oxide p-i-n device. We have characterized the perovskite and carrier collecting materials, such as NiO and MoO3 nanoparticles as p-type materials and ZnO nanoparticles as the n-type material, with scanning tunneling spectroscopy; from the spectrum of the density of states, we could locate the band edges to infer the nature of the active semiconductor materials. The energy level …

Influence Of Polycaprolactone And Basic Fibroblast Growth Factor On Gingival Fibroblasts, Sarah Michelsons

Electronic Thesis and Dissertation Repository

Guided tissue regeneration (GTR) to regenerate periodontal tissue involves placement of a cell-occlusive barrier membrane functionally excluding the gingiva and associated oral epithelium from the periodontal defect. Gingival connective tissue (CT) contains a rich vascular plexus and is a source of progenitor cells which could contribute to periodontal regeneration. We propose the use of a novel biodegradable and bioactive electrospun fibrous polycaprolactone (PCL) scaffold loaded with microspheres releasing basic fibroblast growth factor (bFGF) to promote gingival CT growth while maintaining a barrier to the oral epithelium. Scaffolds supported human gingival fibroblast proliferation and mesenchymal cell infiltration in a bFGF dose …

Acquisition And Reconstruction Techniques For Fat Quantification Using Magnetic Resonance Imaging, Abraam S. Soliman

Electronic Thesis and Dissertation Repository

Quantifying the tissue fat concentration is important for several diseases in various organs including liver, heart, skeletal muscle and kidney. Uniquely, MRI can separate the signal from water and fat in-vivo, rendering it the most suitable imaging modality for non-invasive fat quantification. Chemical-shift-encoded MRI is commonly used for quantitative fat measurement due to its unique ability to generate a separate image for water and fat. The tissue fat concentration can be consequently estimated from the two images. However, several confounding factors can hinder the water/fat separation process, leading to incorrect estimation of fat concentration.

The inhomogeneities of the main …

The Effect Of Diffusive And Convective Sodium Balance During Hemodialysis On Interdialytic Weight Gain, Benjamin Thomson

Electronic Thesis and Dissertation Repository

Patients with end stage renal disease (ESRD) often require hemodialysis treatments in which blood’s water and dissolved solutes undergo diffusion and convection by exposure to an extracorporeal membrane. The leading cause of death in this population is cardiovascular, and how hemodialysis is prescribed alters total sodium balance, a critical determinant of cardiovascular health. We performed retrospective and prospective analysis of data from patients in the Southwestern Ontario Regional Hemodialysis Program. An increased Dialysate sodium (Dial-Na+) to Pre-dialysis plasma sodium (Pre- Na+) concentration difference (DPNa+) leads to adverse clinical outcomes in hemodialysis patients. The post- to pre-dialysis plasma sodium difference (PPNa+) …

Towards Stem Cell Treatment For Duchenne Muscular Dystrophy-Related Cardiomyopathy, Bogdan A. Bondoc

Electronic Thesis and Dissertation Repository

Duchenne muscular dystrophy (DMD) is a progressive muscular degenerative disease affecting 1 in 3,500 boys. Cardiomyopathy is observed in 95% of patients aged 18 and older, accounting for 30% of deaths. While innovative treatments have been employed to curb symptoms in skeletal muscle, few show success in the heart, and no cure for DMD exists. Recently, regenerative therapy using cardiac stem cells (CSCs) has shown very promising results, but efficacy in DMD remains undetermined. This dissertation sought to provide preliminary insight into the effects of murine Sca-1⁺ CSC therapy. Three-dimensional echocardiography was validated and used to gauge cardiomyopathy in …

A Pseudo Non-Cartesian Pulse Sequence For Hyperpolarized Xenon-129 Gas Mri Of Rodent Lungs At Low Magnetic Field Strength, Krzysztof Wawrzyn

Electronic Thesis and Dissertation Repository

Background: Early diagnosis of radiation-induced lung injury (RILI) following radiation therapy is critical for prevention of permanent lung damage. Pulmonary imaging using magnetic resonance imaging (MRI) of the apparent diffusion coefficient (ADC) of hyperpolarized xenon (¹²⁹Xe) gas shows promise for early measurement of RILI.

Methods: An ultra-short echo time imaging sequence based on a pseudo-Cartesian k-space trajectory, known as Sectoral, is implemented at low magnetic field (0.07 T) for efficient use of the non-renewable magnetization of hyperpolarized ¹²⁹Xe gas. A pilot study was performed to demonstrate the feasibility of ADC mapping using the Sectoral sequence …

Developmental Differences In The Influence Of Phonological Similarity On Spoken Word Processing In Mandarin Chinese., Jeffrey G Malins, Danqi Gao, Ran Tao, James R Booth, Hua Shu, Marc F Joanisse, Li Liu, Amy S Desroches

Brain and Mind Institute Researchers' Publications

The developmental trajectory of spoken word recognition has been well established in Indo-European languages, but to date remains poorly characterized in Mandarin Chinese. In this study, typically developing children (N=17; mean age 10; 5) and adults (N=17; mean age 24) performed a picture-word matching task in Mandarin while we recorded ERPs. Mismatches diverged from expectations in different components of the Mandarin syllable; namely, word-initial phonemes, word-final phonemes, and tone. By comparing responses to different mismatch types, we uncovered evidence suggesting that both children and adults process words incrementally. However, we also observed key developmental differences in how subjects treated onset …

Striatum In Stimulus-Response Learning Via Feedback And In Decision Making., Nole M Hiebert, Andrew Vo, Adam Hampshire, Adrian M Owen, Ken N Seergobin, Penny A Macdonald

Brain and Mind Institute Researchers' Publications

Cognitive deficits are recognized in Parkinson's disease. Understanding cognitive functions mediated by the striatum can clarify some of these impairments and inform treatment strategies. The dorsal striatum, a region impaired in Parkinson's disease, has been implicated in stimulus-response learning. However, most investigations combine acquisition of associations between stimuli, responses, or outcomes (i.e., learning) and expression of learning through response selection and decision enactment, confounding these separate processes. Using neuroimaging, we provide evidence that dorsal striatum does not mediate stimulus-response learning from feedback but rather underlies decision making once associations between stimuli and responses are learned. In the experiment, 11 males …

Transcranial Magnetic Stimulation Of The Prefrontal Cortex In Awake Nonhuman Primates Evokes A Polysynaptic Neck Muscle Response That Reflects Oculomotor Activity At The Time Of Stimulation., Chao Gu, Brian D Corneil

Brain and Mind Institute Researchers' Publications

Transcranial magnetic stimulation (TMS) has emerged as an important technique in cognitive neuroscience, permitting causal inferences about the contribution of a given brain area to behavior. Despite widespread use, exactly how TMS influences neural activity throughout an interconnected network, and how such influences ultimately change behavior, remain unclear. The oculomotor system of nonhuman primates (NHPs) offers a potential animal model to bridge this gap. Here, based on results suggesting that neck muscle activity provides a sensitive indicator of oculomotor activation, we show that single pulses of TMS over the frontal eye fields (FEFs) in awake NHPs evoked rapid (within ∼25 …

Regulation Of The High-Affinity Choline Transporter Activity And Trafficking In Alzheimer’S Disease-Related Pathological Conditions, Leah K. Cuddy

Electronic Thesis and Dissertation Repository

Cholinergic neurons play a key role in cognitive processes through the action of the neurotransmitter acetylcholine (ACh). Dysfunction of these neurons occurs in several neurodegenerative disorders, including Alzheimer’s disease (AD). The high-affinity choline transporter CHT recycles choline back into synaptic terminals, which is the rate-limiting step to ACh production. CHT proteins traffic between the cell surface and subcellular organelles in a constitutive manner, which maintains plasma membrane transporter levels, thereby regulating CHT activity and maintaining cholinergic transmission. Pathological conditions associated with AD may alter CHT function in a manner that reduces choline uptake activity and impairs cholinergic neurotransmission. Thus, my …

Euvolemia In Hemodialysis Patients: A Potentially Dangerous Goal?, Shih-Han S Huang, Guido Filler, Robert Lindsay, Chris W Mcintyre

Medical Biophysics Publications

Dialysis patients have high mortality rate and the leading cause of death is cardiovascular disease. Uremic cardiomyopathy differs from that due to conventional atherosclerosis, where cardiovascular changes result in ineffective circulation and lead to tissue ischemia. Modern dialysis has significant limitations with fluid management probably the most challenging. Current evidence suggests that both volume overload and aggressive fluid removal can induce circulatory stress and multi-organ injury. Furthermore, we do not have accurate volume assessment tools. As a result, targeting euvolemia might result in more harm than benefit with conventional hemodialysis therapy. Therefore, it might be time to consider a degree …

Burning Pain Secondary To Clozapine Use: A Case Report., Bradley Linton, Rachel Fu, Penny A Macdonald, Hooman Ganjavi

Brain and Mind Institute Researchers' Publications

BACKGROUND: The first of the atypical antipsychotics introduced in the 1970s, clozapine remains the most efficacious neuroleptic to this day. However, serious and potentially fatal side effects have necessitated careful regular monitoring among prescribing clinicians. Some adverse effects (e.g. ischaemic bowel) remain under recognized, while newly identified adverse effects continue to be described in the literature.

CASE PRESENTATION: In this report, we describe a healthy 43-year old Caucasian male who experienced onset of a full body deep burning pain several months after the onset of treatment with clozapine. The pain worsened over time, ceased with cessation of treatment, and returned …

Quantitative Mri Correlates Of Hippocampal And Neocortical Pathology In Intractable Temporal Lobe Epilepsy, Maged Goubran

Electronic Thesis and Dissertation Repository

Intractable or drug-resistant epilepsy occurs in over 30% of epilepsy patients, with many of these patients undergoing surgical excision of the affected brain region to achieve seizure control. Advances in MRI have the potential to improve surgical treatment of epilepsy through improved identification and delineation of lesions. However, validation is currently needed to investigate histopathological correlates of these new imaging techniques. The purpose of this work is to investigate histopathological correlates of quantitative relaxometry and DTI from hippocampal and neocortical specimens of intractable TLE patients. To achieve this goal I developed and evaluated a pipeline for histology to in-vivo MRI …

The Cost Of Moving Optimally: Kinematic Path Selection., Dinant A Kistemaker, Jeremy D Wong, Paul L Gribble

Brain and Mind Institute Researchers' Publications

It is currently unclear whether the brain plans movement kinematics explicitly or whether movement paths arise implicitly through optimization of a cost function that takes into account control and/or dynamic variables. Several cost functions are proposed in the literature that are very different in nature (e.g., control effort, torque change, and jerk), yet each can predict common movement characteristics. We set out to disentangle predictions of the different variables using a combination of modeling and empirical studies. Subjects performed goal-directed arm movements in a force field (FF) in combination with visual perturbations of seen hand position. This FF was designed …

Quantitative Analysis Of Relaxation Rate Dependence On Interecho Time In Maga-Expressing, Iron-Labeled Cells, Casey Yesol Lee

Electronic Thesis and Dissertation Repository

Reporter gene-based methods of labeling cells with iron is an emerging method of providing magnetic resonance imaging (MRI) contrast for long-term cell tracking and monitoring of cellular activities. This thesis investigates 9.4 T NMR properties of mammalian cells over-expressing a magnetotactic bacterial putative iron transport gene, MagA, and the associated untransfected parental cells. Cells were cultured in medium alone or supplemented with 250 μM ferric nitrate. Using the Carr-Purcell-Meiboom-Gill sequence, the relationship between R2 and interecho time was analyzed for each of the cell types using a model based on water diffusion in weak magnetic field inhomogeneities (Jensen and Chandra, …

Mirror Reversal And Visual Rotation Are Learned And Consolidated Via Separate Mechanisms: Recalibrating Or Learning De Novo?, Sebastian Telgen, Darius Parvin, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

Motor learning tasks are often classified into adaptation tasks, which involve the recalibration of an existing control policy (the mapping that determines both feedforward and feedback commands), and skill-learning tasks, requiring the acquisition of new control policies. We show here that this distinction also applies to two different visuomotor transformations during reaching in humans: Mirror-reversal (left-right reversal over a mid-sagittal axis) of visual feedback versus rotation of visual feedback around the movement origin. During mirror-reversal learning, correct movement initiation (feedforward commands) and online corrections (feedback responses) were only generated at longer latencies. The earliest responses were directed into a nonmirrored …

Dopaminergic Therapy Affects Learning And Impulsivity In Parkinson's Disease., Nole M Hiebert, Ken N Seergobin, Andrew Vo, Hooman Ganjavi, Penny A Macdonald

Brain and Mind Institute Researchers' Publications

OBJECTIVE: The aim was to examine the effect of dopaminergic medication on stimulus-response learning versus performing decisions based on learning.

METHOD: To see the effect of dopaminergic therapy on stimulus-response learning and response selection, participants with Parkinson's disease (PD) were either tested on and/or off their prescribed dose of dopaminergic therapy during different testing days. Forty participants with PD and 34 healthy controls completed the experiment on consecutive days. On Day 1, participants learned to associate abstract images with spoken, "right" or "left" responses via feedback (Session 1). On Day 2, participants recalled these responses (Session 2) and indicated the …

Developmental Stress, Condition, And Birdsong: A Case Study In Song Sparrows., Kim L Schmidt, Elizabeth A Macdougall-Shackleton, Shawn P Kubli, Scott A Macdougall-Shackleton

Brain and Mind Institute Researchers' Publications

Sexual-selection theory posits that ornaments and displays can reflect a signaler's condition, which in turn is affected both by recent and developmental conditions. Moreover, developmental conditions can induce correlations between sexually selected and other traits if both types of traits exhibit developmental phenotypic plasticity in response to stressors. Thus, sexually selected traits may reflect recent and/or developmental characteristics of signalers. Here, we review data on the relationships between birdsong, a sexually selected trait, and developmental and current condition of birds from a long-term study of a population of song sparrows (Melospiza melodia). Field studies of free-living birds indicate that the …

Ct Perfusion Imaging As An Early Biomarker Of Differential Response To Stereotactic Radiosurgery In C6 Rat Gliomas, Timothy Pok Chi Yeung, Maher Kurdi, Yong Wang, Baraa Al-Khazraji, Laura Morrison, Lisa Hoffman, Dwayne Jackson, Cathie Crukley, Ting-Yim Lee, Glenn Bauman, Slav Yartsev

Medical Biophysics Publications

BACKGROUND: The therapeutic efficacy of stereotactic radiosurgery for glioblastoma is not well understood, and there needs to be an effective biomarker to identify patients who might benefit from this treatment. This study investigated the efficacy of computed tomography (CT) perfusion imaging as an early imaging biomarker of response to stereotactic radiosurgery in a malignant rat glioma model.

METHODS: Rats with orthotopic C6 glioma tumors received either mock irradiation (controls, N = 8) or stereotactic radiosurgery (N = 25, 12 Gy in one fraction) delivered by Helical Tomotherapy. Twelve irradiated animals were sacrificed four days after stereotactic radiosurgery to assess acute …