Browsing by Author "Rossmeisl, John H. Jr."
Now showing 1 - 20 of 43
Results Per Page
Sort Options
- 7.0-T Magnetic Resonance Imaging Characterization of Acute Blood-Brain-Barrier Disruption Achieved with Intracranial Irreversible ElectroporationGarcia, Paulo A.; Rossmeisl, John H. Jr.; Robertson, John L.; Olson, JohnD.; Johnson, Annette J.; Ellis, Thomas L.; Davalos, Rafael V. (PLOS, 2012-11-30)The blood-brain-barrier (BBB) presents a significant obstacle to the delivery of systemically administered chemotherapeutics for the treatment of brain cancer. Irreversible electroporation (IRE) is an emerging technology that uses pulsed electric fields for the non-thermal ablation of tumors. We hypothesized that there is a minimal electric field at which BBB disruption occurs surrounding an IRE-induced zone of ablation and that this transient response can be measured using gadolinium (Gd) uptake as a surrogate marker for BBB disruption. The study was performed in a Good Laboratory Practices (GLP) compliant facility and had Institutional Animal Care and Use Committee (IACUC) approval. IRE ablations were performed in vivo in normal rat brain (n = 21) with 1-mm electrodes (0.45 mm diameter) separated by an edge-to-edge distance of 4 mm. We used an ECM830 pulse generator to deliver ninety 50-ms pulse treatments (0, 200, 400, 600, 800, and 1000 V/cm) at 1 Hz. The effects of applied electric fields and timing of Gd administration (25, +5, +15, and +30 min) was assessed by systematically characterizing IRE-induced regions of cell death and BBB disruption with 7.0-T magnetic resonance imaging (MRI) and histopathologic evaluations. Statistical analysis on the effect of applied electric field and Gd timing was conducted via Fit of Least Squares with a = 0.05 and linear regression analysis. The focal nature of IRE treatment was confirmed with 3D MRI reconstructions with linear correlations between volume of ablation and electric field. Our results also demonstrated that IRE is an ablation technique that kills brain tissue in a focal manner depicted by MRI (n = 16) and transiently disrupts the BBB adjacent to the ablated area in a voltage-dependent manner as seen with Evan’s Blue (n = 5) and Gd administration.
- Canine Butterfly Glioblastomas: a Neuroradiological ReviewRossmeisl, John H. Jr.; Clapp, Kemba; Pancotto, Theresa E.; Emch, Samantha; Robertson, John L.; Debinski, Waldemar (Frontiers, 2016-05-19)In humans, high-grade gliomas may infiltrate across the corpus callosum resulting in bihemispheric lesions that may have symmetrical, winged-like appearances. This particular tumor manifestation has been coined a “butterfly” glioma (BG). While canine and human gliomas share many neuroradiological and pathological features, the BG morphology has not been previously reported in dogs. Here, we describe the magnetic resonance imaging (MRI) characteristics of BG in three dogs and review the potential differential diagnoses based on neuroimaging findings. All dogs presented for generalized seizures and interictal neurological deficits referable to multifocal or diffuse forebrain disease. MRI examinations revealed asymmetrical (2/3) or symmetrical (1/3), bihemispheric intra-axial mass lesions that predominantly affected the frontoparietal lobes that were associated with extensive perilesional edema, and involvement of the corpus callosum. The masses displayed heterogeneous T1, T2, and fluid-attenuated inversion recovery signal intensities, variable contrast enhancement (2/3), and mass effect. All tumors demonstrated classical histopathological features of glioblastoma multiforme (GBM), including glial cell pseudopalisading, serpentine necrosis, microvascular proliferation as well as invasion of the corpus callosum by neoplastic astrocytes. Although rare, GBM should be considered a differential diagnosis in dogs with an MRI evidence of asymmetric or symmetric bilateral, intra-axial cerebral mass lesions with signal characteristics compatible with glioma.
- Canine Snake-Eye Myelopathy: Clinical, Magnetic Resonance Imaging, and Pathologic Findings in Four CasesRossmeisl, John H. Jr.; Cecere, Thomas E.; Kortz, Gregg D.; Geiger, David A.; Shinn, Richard L.; Hinckley, Jonathan; Caudell, David L.; Stahle, Jessica A. (Frontiers, 2019-07-05)Intramedullary signal change (ISC) is a non-specific finding that is frequently observed on magnetic resonance imaging (MRI) examinations of the canine spinal cord. ISC can represent a variety of primary pathological processes such as neoplasms or myelitides or secondary changes such as edema, cysts, gliosis, or myelomalacia. An unusual phenotype of ISC is the "snake-eye" myelopathy (SEM), which refers to bilaterally symmetric T2 hyperintensities preferentially affecting the ventral horn gray matter on transverse MR images, which resemble a pair of snake's eyes. The pathophysiology of SEM is poorly understood in humans, and this imaging finding may be associated with cervical spondylotic myelopathy, spinal cord ischemia, ossification of the posterior longitudinal ligament, amyotrophic lateral sclerosis, and Hirayama disease. Here we describe four dogs with cervical MRI examinations consistent with an SEM-like phenotype. All dogs initially presented with a central cord syndrome or tetraparesis referable to a C6-T2 neuroanatomic localization, which was attributed to disc-associated spinal cord compression in three cases, while one dog had the SEM-like phenotype with no identifiable etiology. Once the SEM-like phenotype was present on MRI examinations, dogs demonstrated insidious clinical deterioration despite therapeutic interventions. Deterioration was characterized by lower motor neuron weakness and neurogenic muscle atrophy progressing to paralysis in the thoracic limbs, while neurological functions caudal to the level of the SEM-like lesion remained largely preserved for months to years thereafter. Neuropathological features of the SEM-like phenotype include multisegmental cavitations and poliomyelomalacia of laminae VI-IX of the caudal cervical spinal cord, although the lesion evolved into pan-necrosis of gray matter with extension into the adjacent white matter in one case with an 8 years history of progressive disease. Although the pathophysiology of SEM remains unknown, the topographical distribution and appearance of lesions is suggestive of a vascular disorder. As the SEM-like phenotype was uniformly characterized by longitudinally and circumferentially extensive neuronal necrosis, results of this small case series indicate that dogs with clinical signs of central cord syndrome and the SEM-like phenotype involving the cervicothoracic intumescence on MR examinations have a poor prognosis for the preservation or recovery of thoracic limb motor function.
- A case of stiff dog syndrome associated with anti-glutamic acid decarboxylase antibodiesPancotto, Theresa E.; Rossmeisl, John H. Jr. (2017-05-10)Background The stiff person syndrome (SPS) is a rare and debilitating autoimmune disorder with an unknown pathogenesis and variable clinical presentation that can present a diagnostic challenge. Although entities that clinically mimic stiff-person spectrum disorders (SPSD) have manifested in horses, they have not been reported in dogs. Case presentation We describe a 2-year-old beagle dog presented for progressive attacks of muscular rigidity and lordosis with superimposed spasms of the appendicular muscles triggered by tactile stimulation which resulted in marked gait impairment. Resting electromyography revealed continuous motor unit activity in the axial musculature. Compared to age-matched healthy beagle dogs, this patient had elevated glutamic acid decarboxylase antibody concentrations in serum and cerebrospinal fluid. Conclusions This dog presented with phenotypic, electrodiagnostic, and immunologic criterion consistent with an SPSD, including elevated anti-GAD antibody titers, which we have termed the “stiff dog syndrome (SDS)”. Durable clinical improvement was achieved with symptomatic and immunosuppressive treatments including baclofen, gabapentin, prednisone, and intravenous immunoglobulin.
- Comparison of direct measurement of intracranial pressures and presumptive clinical and magnetic resonance imaging indicators of intracranial hypertension in dogs with brain tumorsGiannasi, Savannah; Kani, Yukitaka; Hsu, Fang-Chi; Rossmeisl, John H. Jr. (2020-05-16)Background Intracranial hypertension (ICH) is often presumptively diagnosed based on clinical or imaging findings. Clinical or imaging surrogates of ICH are not usually validated with reference standard direct intracranial pressure (dICP) recordings. Hypotheses Dogs with brain magnetic resonance imaging (MRI) or clinical features of presumed ICH would have higher dICP than dogs lacking those features. Animals Twenty dogs with gliomas and 3 normal controls. Methods Prospective, convenience study. Dogs were presumptively categorized with normal ICP or ICH from scores generated from described clinical and brain MRI indicators of ICH. dICP was recorded in anesthetized dogs using an intraparenchymal microsensor and compared between groups. Results dICP was not different between control (10.4 +/- 2.1 mm Hg) and dogs with glioma (15.6 +/- 8.3 mm Hg), or between dogs in clinically predicted ICP groups. Compared with dogs with MRI-predicted normal ICP, MRI-predicted ICH dogs had higher dICP (10.3 +/- 4.1 versus 19.2 +/- 7.9 mm Hg, P = .004), larger tumors (1.45 +/- 1.2 versus 5.71 +/- 3.03 cm(3), P = .0004), larger optic nerve sheath diameters, and 14/14 (100%) displayed structural anatomical shifts on MRI. At a dICP threshold of 15 mm Hg, the sensitivity of MRI for predicting ICH was 90% and the specificity 69%. Conclusions and Clinical Relevance dICP measurements are feasible in dogs with brain tumors. MRI features including brain herniations, mass effect, and optic nerve size aid in the identification of dogs with ICH. Clinical estimation of ICP did not discriminate between dogs with and without ICH.
- Computed Tomography and Magnetic Resonance Imaging Are Equivalent in Mensuration and Similarly Inaccurate in Grade and Type Predictability of Canine Intracranial GliomasStadler, Krystina L.; Ruth, Jeffrey D.; Pancotto, Theresa E.; Werre, Stephen R.; Rossmeisl, John H. Jr. (Frontiers, 2017-09-25)While magnetic resonance imaging (MRI) is the gold-standard imaging modality for diagnosis of intracranial neoplasia, computed tomography (CT) remains commonly used for diagnosis and therapeutic planning in veterinary medicine. Despite the routine use of both imaging modalities, comparison of CT and MRI has not been described in the canine patient. A retrospective study was performed to evaluate CT and MRI studies of 15 dogs with histologically confirmed glioma. Multiple lesion measurements were obtained, including two-dimensional and volumetric dimensions in pre-contrast and post-contrast images. Similar measurement techniques were compared between CT and MRI. The glioma type (astrocytoma or oligodendroglioma) and grade (high or low) were predicted on CT and MRI independently. With the exception of the comparison between CT pre-contrast volume to T2-weighted MRI volume, no other statistical differences between CT and MRI measurements were identified. Overall accuracy for tumor grade (high or low) was 46.7 and 53.3% for CT and MRI, respectively. For predicted tumor type, accuracy of CT was 53.3% and MRI and MRI 60%. Based on the results of this study, both CT and MRI contrast measurement techniques are considered equivalent options for lesion mensuration. Given the low-to-moderate predictability of CT and MRI in glioma diagnosis, histopathology remains necessary for accurate diagnosis of canine brain tumors.
- Creation and Characterization of Several Polymer/Conductive Element Composite Scaffolds for Skeletal Muscle Tissue EngineeringFischer, Kristin Mckeon (Virginia Tech, 2012-02-17)After skeletal muscle damage, satellite cells move towards the injured area to assist in regeneration. However, these cells are rare as their numbers depend on the age and composition of the injured muscle. This regeneration method often results in scar tissue formation along with loss of function. Although several treatment methods have been investigated, no muscle replacement treatment currently exists. Tissue engineering attempts to create, repair, and/or replace damaged tissue by combining cells, biomaterials, and tissue-inducing substances such as growth factors. Electrospinning produces a non-woven scaffold out of biomaterials with fiber diameters ranging from nanometers to microns to create an extracellular-like matrix on which cells attach and proliferate. Our focus is on synthetic polymers, specifically poly(D,L-lactide) (PDLA), poly(L-lactide) (PLLA), and poly(ε-caprolactone) (PCL). Skeletal muscle cells grown on electrospun scaffolds tend to elongate and fuse together thus, mimicking natural tissue. Electrical stimulation has been shown to increase the number of cells fused in culture and decreased the time needed in culture for cells to contract. Therefore, a conductive element was added to each scaffold, specifically polyaniline (PANi), gold nanoparticles (Au Nps), and multi-walled carbon nanotubes (MWCNT). Our project goal is to create a polymeric, conductive, and biocompatible scaffold for skeletal muscle regeneration. PANi and PDLA were mixed to form the following solutions 24% (83% PDLA/17% PANi), 24% (80% PDLA/20% PANi), 22% (75%PDLA/25% PANi), 29% (83% PDLA/17% PANi), and 29% (80% PDLA/20% PANi). Only the 75/25 electrospun scaffold was conductive and had a calculated conductivity of 0.0437 S/cm. Scaffolds with larger amounts of PANi were unable to be electrospun. PDLA/PANi scaffolds were biocompatible as primary rat skeletal muscle cells cultured in vitro did attach. However, the scaffolds shrunk, degraded easily, and became brittle. Although PDLA/PANi scaffolds were easily manufactured, our results indicate that this polymer mixture is not appropriate for skeletal muscle scaffolds. PLLA and Au Nps were electrospun together to form three composite scaffolds: 7% Au-PLLA, 13% Au-PLLA, and 21% Au-PLLA. These were compared to PLLA electrospun scaffolds. Measured scaffold conductivities were 0.008 ± 0.015 S/cm for PLLA, 0.053 ± 0.015 S/cm for 7% Au-PLLA, 0.076 ± 0.004 S/cm for 13% Au-PLLA, and 0.094 ± 0.037 S/cm for 21% Au-PLLA. It was determined via SEM with a Bruker energy dispersive x-ray spectrometer (EDS) that the Au Nps were not evenly distributed within the scaffolds as they had agglomerated. Rat primary muscle cells cultured on the three Au-PLLA scaffolds displayed low cellular activity. A second cell study was conducted to determine Au NPs toxicity. The results show that the Au Nps were not toxic to the cells and the low cellular activity may be a marker for myotube fusion. Elastic modulus and yield stress values for the three Au-PLLA scaffolds measured on days 0, 7, 14, 21, and 28 were much larger than skeletal muscle tissue. Due to the larger mechanical properties and Au Nps agglomeration, a third polymer and conductive element scaffold was investigated. PCL was chosen as the new synthetic polymer as it had a lower elastic modulus and high elongation. MWCNT were chosen as the conductive element as they disperse well within PCL when acid functionalized. A third component was added to the scaffold to help it move similar to skeletal muscle. Ionic polymer gels (IPG) are hydrogels that respond to an external stimulus such as temperature, pH, light, and electric field. A poly(acrylic acid)/poly(vinyl alcohol) (PAA/PVA) mixture is one type of IGP that responds to an electric field. The scaffolds were coaxially electrospun so that each fiber had a PCL-MWCNT interior with a PAA/PVA sheath. These scaffolds were compared to electrospun PCL and PCL-MWCNT ones. The addition of MWCNT to the PCL did increase scaffold conductivity. Actuation of the PCL-MWCNT-PAA/PVA scaffold occurred when 15V and 20V were applied. All three scaffolds had rat primary skeletal muscle cells attached but, more multinucleated cells with actin interaction were seen on PCL-MWCNT-PAA/PVA scaffolds. Once again the mechanical properties were greater than muscle, but because of its ability to actuate we believe the PCL-MWCNT-PAA/PVA scaffold has potential as a bioartificial muscle. Further characterization of the PCL-MWCNT-PAA/PVA included varying the ratios of PAA/PVA, smaller crosslinking times, and lower amounts of MWCNT. Four ratios, 83/17, 60/40, 50/50, and 40/60, were successfully coaxially electrospun with PCL and MWCNT. Overall, very few differences were seen between the four ratios in conductivity, cellular biocompatibility, actuation angular speed, and mechanical properties. The 83/17 and 40/60 ratios were chosen for additional investigation into mechanical properties and actuation. As the mechanical properties of the two types of scaffolds did not change significantly through degradation, lower PVA crosslinking times were tested. No significant effects were found and it was hypothesized that the evaporation of the solution played a role in the crosslinking process. The smaller MWCNT amount scaffolds also did not significantly affect the mechanical properties or the actuation angular speeds. More work into lowering the scaffold mechanical properties while increasing the actuation angular speed is necessary. Though the mechanical properties for the 83/17 and 40/60 scaffolds remained high compared to skeletal muscle, we also looked for differences in in vivo biocompatibility. Both scaffolds were implanted into the right vastus lateralis muscle of Sprague-Dawley rats. The left vastus lateralis muscle served as either the PBS injected sham surgery or an unoperated control. Biocompatibility was evaluated using enzymes, creatine kinase (CK) and lactate dehydrogenase (LDH), levels, fibrosis formation, inflammation, scaffold cellular infiltration, and neovascularization on days 7, 14, 21, and 28 post-implantation. Fibrotic tissue formation, inflammation, and elevated CK and LDH levels were observed initially but responses decreased during the four week study. Cells infiltrated the scaffolds and histological staining showed more fibroblasts than myogenic cells initially but over time, the fibroblasts decreased and myogenic cells increased. Neovascularization of both scaffolds was also recorded. PCL-MWCNT-PAA/PVA scaffolds were determined to be biocompatible, but some differences between the two types were noted. The 83/17 scaffolds caused less of a response from the body compared to the 40/60 scaffolds and had more myogenic cells attached. However, the 40/60 scaffolds had a larger number of blood vessels running through the scaffold. In conclusion, we have successfully fabricated a polymeric, conductive, and biocompatible scaffold that can actuate for skeletal muscle tissue engineering. Although our results are promising, more work is necessary to continue developing and refining the scaffold.
- Cross-species transcriptional analysis reveals conserved and host-specific neoplastic processes in mammalian gliomaConnolly, Nina P.; Shetty, Amol C.; Stokum, Jesse A.; Hoeschele, Ina; Siegel, Marni B.; Miller, C. Ryan; Kim, Anthony J.; Ho, Cheng-Ying; Davila, Eduardo; Simard, J. Marc; Devine, Scott E.; Rossmeisl, John H. Jr.; Holland, Eric C.; Winkles, Jeffrey A.; Woodworth, Graeme F. (Springer Nature, 2018-01-19)Glioma is a unique neoplastic disease that develops exclusively in the central nervous system (CNS) and rarely metastasizes to other tissues. This feature strongly implicates the tumor-host CNS microenvironment in gliomagenesis and tumor progression. We investigated the differences and similarities in glioma biology as conveyed by transcriptomic patterns across four mammalian hosts: rats, mice, dogs, and humans. Given the inherent intra-tumoral molecular heterogeneity of human glioma, we focused this study on tumors with upregulation of the platelet-derived growth factor signaling axis, a common and early alteration in human gliomagenesis. The results reveal core neoplastic alterations in mammalian glioma, as well as unique contributions of the tumor host to neoplastic processes. Notable differences were observed in gene expression patterns as well as related biological pathways and cell populations known to mediate key elements of glioma biology, including angiogenesis, immune evasion, and brain invasion. These data provide new insights regarding mammalian models of human glioma, and how these insights and models relate to our current understanding of the human disease.
- Development and Evaluation of a Caregiver Reported Quality of Life Assessment Instrument in Dogs With Intracranial DiseaseWeiske, Rebecca; Sroufe, Maureen; Quigley, Mindy; Pancotto, Theresa E.; Werre, Stephen R.; Rossmeisl, John H. Jr. (2020-08-18)In veterinary medicine, quality of life (QOL) assessment instruments, which are important components of the holistic evaluation of treatment success, have largely not included organ-specific concerns that may be broadly relevant to caregivers of dogs with intracranial disease. The objective of this study was to identify core questionnaire items and domains that contribute to health-related QOL (HRQOL) in dogs with intracranial disease. A questionnaire was developed that contained 39 QOL-related items encompassing physical, social/companionship, and brain-specific domains associated with the treatment of dogs with intracranial disease, and administered to caregivers of 56 dogs diagnosed with genetic, inflammatory, neoplastic, traumatic, and vascular brain diseases, 52 healthy dogs, and 20 dogs with non-neurological illnesses. Clinician derived functional measures of each dog's health status including chronic pain, Karnofsky performance, and modified Glasgow coma scale scores were also recorded. Principal component analysis refined the final questionnaire, termed the CanBrainQOL-24, to 24-items within the three domains with a minimum Cronbach's alpha of 0.7, indicative of good internal consistency. The CanBrainQOL-24 discriminated between healthy and diseased dogs. Physical and brain-specific domains were significantly different between dogs with intracranial and non-neurological diseases. Significant correlations were observed between owner reported visual analog scores and CanBrainQOL-24 scores, as well between clinician derived functional status measures and owner reported QOL. The CanBrainQOL-24 contains core questions relevant to caregiver assessment of HRQOL in dogs with a variety of intracranial diseases, and provides information that is complementary to clinician derived functional outcome measures.
- Diagnostic accuracy of stereotactic brain biopsy for intracranial neoplasia in dogs: Comparison of biopsy, surgical resection, and necropsy specimensKani, Yukitaka; Cecere, Thomas E.; Lahmers, Kevin K.; LeRoith, Tanya; Zimmerman, Kurt L.; Isom, Scott; Hsu, Fang-Chi; Debinski, Waldemar; Robertson, John L.; Rossmeisl, John H. Jr. (American College of Veterinary Internal Medicine, 2019-05)Background Stereotactic brain biopsy (SBB) is a technique that allows for definitive diagnosis of brain lesions. Little information is available regarding the diagnostic utility of SBB in dogs with intracranial diseases. Objective To investigate the diagnostic accuracy (DA) of SBB in dogs with brain tumors. Animals Thirty-one client-owned dogs that underwent SBB followed by surgical resection or necropsy examinations. Methods Retrospective observational study. Two pathologists blinded to SBB and reference standard diagnoses reviewed histologic specimens and typed and graded tumors according to World Health Organization and revised canine glioma classification criteria. Agreement between tumor type and grade from SBB were compared to reference standards and assessed using kappa statistics. Patient and technical factors associated with agreement also were examined. Results Stereotactic brain biopsy specimens were obtained from 24 dogs with gliomas and 7 with meningiomas. Tumor type agreement between SBB and the reference standard was observed in 30/31 cases (kappa = 0.95). Diagnostic concordance was perfect for meningiomas. Grade agreement among gliomas was observed in 18/23 cases (kappa = 0.47). Stereotactic brain biopsy underrepresented the reference standard glioma grade in cases with disagreement. The DA of SBB was 81%, with agreement noted in 56/69 biopsy samples. Smaller tumors and fewer SBB specimens obtained were significantly associated with diagnostic discordance. Conclusions and Clinical Importance The DA of SBB readily allows for the diagnosis of common brain tumors in dogs. Although glioma grade discordance was frequent, diagnoses obtained from SBB are sufficient to currently inform therapeutic decisions. Multiple SBB specimens should be collected to maximize DA.
- Effects of Blood Contamination on Cerebrospinal Fluid Cell Counts, Protein, and D-dimer ConcentrationsRossmeisl, John H. Jr. (Virginia Tech, 2003-01-20)Cerebrospinal fluid analysis (CSF) is commonly performed in clinical neurology, and is a sensitive, but non-specific indicator of central nervous system (CNS) pathology. Blood contaminated CSF samples have the potential to adversely affect results of cytologic, serologic, microbiologic, and molecular biologic diagnostics. A clear consensus of the effects of blood contamination on CSF analysis could not be drawn following a review of the existing veterinary literature. Based on data from earlier reports, it was hypothesized that iatrogenic blood contamination of CSF would result in significant increases in both the CSF total protein (TP) concentration and nucleated cell count (WBC). As hypothesized, in vitro CSF blood contamination resulted in statistically significant (p < 0.01) linear increases in both the CSF TP and WBC with increasing RBC concentration in CSF from sixteen normal dogs. Although increases in TP and WBC are statistically significant, their clinical impact is negligible. Results of this study demonstrate that in normal dogs, the mean CSF TP concentration collected from the cerebellomedullary cistern, is lower than previously reported. D-dimers are plasminolytic cleavage products formed by the cross-linkage of fibrin by Factor XIIIa. In humans, D-dimer analysis can be used to differentiate iatrogenic from pathologic CNS hemorrhage. An additional objective of this study was to determine if canine D-dimers could be assayed using commercially available latex agglutination (LA) and enzymatic immunoassay (EIA) kits in normal and diseased subjects. It was hypothesized that qualitative and quantitative determinations of blood and CSF D-dimer activities could be aid in the diagnosis of dogs with altered CNS and/or systemic coagulation. D-dimers were able to be assayed in all subjects studied. D-dimer concentrations in CSF samples, when analyzed using a qualitative LA assay system, from healthy dogs with iatrogenically blood contaminated CSF were consistently negative. Quantitation of CSF D-dimer concentrations in normal dogs using an EIA assay resulted in lower values (mean 16.2 + 4.3 ng/ml; range, 0 to 54 ng/ml) than detected in the peripheral blood of dogs and humans (normal cutoff value < 250 ng/ml). These findings suggest that D-dimer formation does not occur in canine CSF freshly contaminated with blood. Significantly (p < 0.001) higher mean blood D-dimer concentrations were present in dogs with systemic coagulation disorders (1,093.4 + 172.3 ng/ml; range, 0 to > 2,000 ng/ml) when compared to normal dogs (54.6 + 19.8 ng/ml; range, 0 to 190 ng/ml), when assayed with the EIA. When used as an adjunct in the diagnosis of systemic coagulation abnormalities, the EIA assay had an overall sensitivity of 92%, specificity of 100%, positive predictive value (PPV) of 100%, and negative predictive value (NPV) of 94%. When applied to the same dogs, the LA D-dimer was less sensitive and specific (sensitivity of 73%, specificity of 100%, PPV of 100%, and NPV of 80%) than the EIA. Evidence of intrathecal fibrinolysis in the absence of systemic abnormalities was also demonstrated using CSF LA and EIA D-dimer assays in some dogs with a variety of infectious (Rocky mountain spotted fever), non-infectious inflammatory (granulomatous meningoencephalitis, steroid-responsive meningitis), traumatic (intervertebral disc disease, spinal fracture), and neoplastic (meningioma) diseases. When all dogs with CNS diseases were examined together, the mean EIA D-dimer concentration was significantly (p = 0.03) higher (511.6 + 279.8 ng/ml) than normal dogs (mean 16.2 + 4.3 ng/ml). Future studies will be required before the definitive role of D-dimer analysis can be defined in veterinary medicine.
- Evaluating the Expression of Angiogenic Mediators in a Mouse Model of Tumor MetastasisCrawford, Natalie M. (Virginia Tech, 2008-07-03)Solid tumors typically require angiogenesis, the development of new blood vessels, for growth and metastasis. Vascular endothelial growth factor (VEGF) induces angiogenesis by activating receptors on host endothelial cells. One such receptor, Flt-1, occurs as either a membrane bound or a secreted form (sFlt-1) that can inhibit angiogenic signaling. Previous studies have shown that variation in mRNA expression of VEGF and its receptors KDR, sFlt-1 and Flt-1 occurs in pathological angiogenesis, i.e. metastatic tumorigenesis. We hypothesize that the ratio of sFlt-1:Flt-1 mRNA will be altered in the presence of solid tumors. The objective of this study was to evaluate the expression of sFlt-1 and Flt-1 mRNAs in a mouse metastatic tumor model using CT26.CL25 cells. CT26.CL25 cells are VEGF-producing murine colon carcinoma cells transfected with the lacZ gene, which expresses B-galactosidase activity. These cells, injected intravenously, form tumor nodules in the lung. A pilot study revealed development of lung nodules in mice nine days after intravenous injection with 105 cells. In a second study, twenty-five 10- week-old female Balb/c mice were injected intravenously, via tail vein, with 2 x 105cells, and fifteen with vehicle control. Lung nodules developed in all mice injected with cells. Tissues were harvested by routine necropsy and either formalin-fixed for routine histology/histochemistry or stored for quantitative RT-PCR (QPCR) analysis of gene expression. Under microscopic evaluation, sections of lungs stained with Hematoxylin & Eosin (H&E) revealed nodules composed of polygonal neoplastic cells. cDNA from lungs (14 tumor-bearing, 10 controls) and cultured CT26.CL25 cells was analyzed by QPCR using primers and TaqMan probes directed against sFlt-1, Flt-1, KDR, VEGFA, PlGF (Placental Growth Factor), Angiotensin Converting Enzyme (ACE), 18S ribosomal RNA and neoR (neomycin phosphotransferase). We observed an increased sFlt-1:Flt-1 ratio in tumor-bearing versus control lungs, suggesting that tumor-derived signals may influence sFlt-1 and Flt-1 expression differentially. Additionally, there was increased expression of Flt-1, sFlt-1 and KDR in tumors versus controls, but not in VEGF expression in tumors versus controls. Interestingly, expression of PlGF was increased in tumors versus controls, suggesting its role as an enhancer of tumor progression in the presence of other angiogenic factors. Together, these findings indicate that solid tumor angiogenesis results from an intricate balance of various angiogenic factors.
- Evaluation of cerebrospinal fluid biomarkers of endothelial damage and basement membrane degradation as indirect indicators of blood-brain barrier dysfunction in chronic canine hypothyroidismPancotto, Theresa E. (Virginia Tech, 2011-02-24)A variety of neurologic illnesses including peripheral and cranial neuropathies, central vestibular disease, seizures and coma have been associated with hypothyroidism in dogs. Repeated studies have shown that there is loss of blood brain barrier (BBB) integrity in these animals. Current research has also shown the development cerebrospinal fluid abnormalities in neurologically normal hypothyroid dogs; a finding that is related to BBB degradation. This derangement may be secondary to atherosclerosis and vascular accidents. One possible mediator of vasospasm and ischemic brain injury is endothelin-1 (ET-1). Another group of mediators of vascular dysfunction that has been found in CSF of dogs with various other CNS diseases is matrix metalloproteinases (MMP). The purpose of this study was to assay molecular markers that may contribute to disruption in the blood brain barrier in chronically hypothyroid canines. We hypothesized that BBB disruption in hypothyroidism is mediated by ET-1 and MMPs, as evidenced by increased concentrations of these proteins in CSF compared to controls. Cerebrospinal fluid (CSF) previously collected from 9 control and 9 experimentally induced hypothyroid dogs was used. Administration of I-131 was used to create the experimental model. CSF from time points 0, 6, 12, and 18 months post-induction were evaluated using an ELISA kit for endothelin-1. CSF from each time point was also evaluated using gelatinase zymography to detect MMP-2,9, and 14. The endothelin assay was able to detect ET-1 in CSF as determined by a spike and recovery method. However, ET-1 was undetectable in CSF of control and hypothyroid dogs at all time points. Constitutively expressed MMP-2 was detectable in all dogs at all time points. No other MMPs were detectable in CSF. ET-1 and gelatinase MMP,-9, and -14 are not primary mediators of BBB damage in chronically hypothyroid dogs. They could be involved secondarily and may be better evaluated with different assays or in temporal association with the development of clinical signs of neurologic dysfunction. Additional research is needed to confirm this finding and to evaluate biomarkers of non-vascular components of the BBB.
- Expression and activity of the urokinase plasminogen activator system in canine primary brain tumorsRossmeisl, John H. Jr.; Hall-Manning, Kelli; King, Jamie N.; Davalos, Rafael V.; Debinski, Waldemar; Elankumaran, Subbiah (Dove Press, 2017-04-12)Background: The expression of the urokinase plasminogen activator receptor (uPAR), a glycosylphosphatidylinositol-anchored protein family member, and the activity of its ligand, urokinase-type plasminogen activator (uPA), have been associated with the invasive and metastatic potentials of a variety of human brain tumors through their regulation of extracellular matrix degradation. Domesticated dogs develop naturally occurring brain tumors that share many clinical, phenotypic, molecular, and genetic features with their human counterparts, which has prompted the use of the dogs with spontaneous brain tumors as models to expedite the translation of novel brain tumor therapeutics to humans. There is currently little known regarding the role of the uPA system in canine brain tumorigenesis. The objective of this study was to characterize the expression of uPAR and the activity of uPA in canine brain tumors as justification for the development of uPAR-targeted brain tumor therapeutics in dogs. Methods: We investigated the expression of uPAR in 37 primary canine brain tumors using immunohistochemistry, Western blotting, real-time quantitative polymerase chain reaction analyses, and by the assay of the activity of uPA using casein–plasminogen zymography. Results: Expression of uPAR was observed in multiple tumoral microenvironmental niches, including neoplastic cells, stroma, and the vasculature of canine brain tumors. Relative to normal brain tissues, uPAR protein and mRNA expression were significantly greater in canine meningiomas, gliomas, and choroid plexus tumors. Increased activity of uPA was documented in all tumor types. Conclusions: uPAR is overexpressed and uPA activity increased in canine meningiomas, gliomas, and choroid plexus tumors. This study illustrates the potential of uPAR/uPA molecularly targeted approaches for canine brain tumor therapeutics and reinforces the translational significance of canines with spontaneous brain tumors as models for human disease.
- Feasibility and accuracy of 3D printed patient-specific skull contoured brain biopsy guidesShinn, Richard L.; Park, Clair; DeBose, Kyrille; Hsu, Fang-Chi; Cecere, Thomas E.; Rossmeisl, John H. Jr. (2021-07)Objective Design 3D printed skull contoured brain biopsy guides (3D-SCGs) from computed tomography (CT) or T1-weighted magnetic resonance imaging (T1W MRI). Study Design Feasibility study. Sample Population Five beagle dog cadavers and two client-owned dogs with brain tumors. Methods Helical CT and T1W MRI were performed on cadavers. Planned target point was the head of the caudate nucleus. Three-dimensional-SCGs were created from CT and MRI using commercially available open-source software. Using 3D-SCGs, biopsy needles were placed into the caudate nucleus in cadavers, and CT was performed to assess needle placement accuracy, followed by histopathology. Three-dimensional-SCGs were then created and used to perform in vivo brain tumor biopsies. Results No statistical difference was found between the planned target point and needle placement. Median needle placement error for all planned target points was 2.7 mm (range: 0.86-4.5 mm). No difference in accuracy was detected between MRI and CT-designed 3D-SCGs. Median needle placement error for the CT was 2.8 mm (range: 0.86-4.5 mm), and 2.2 mm (range: 1.7-2.7 mm) for MRI. Biopsy needles were successfully placed into the target in the two dogs with brain tumors and biopsy was successfully acquired in one dog. Conclusion Three-dimensional-SCGs designed from CT or T1W MRI allowed needle placement within 4.5 mm of the intended target in all procedures, resulting in successful biopsy in one of two live dogs. Clinical Significance This feasibility study justifies further evaluation of 3D-SCGs as alternatives in facilities that do not have access to stereotactic brain biopsy.
- Frame-Based Stereotactic Biopsy of Canine Brain Masses: Technique and Clinical Results in 26 CasesRossmeisl, John H. Jr.; Andriani, Rudy T.; Cecere, Thomas E.; Lahmers, Kevin K.; LeRoith, Tanya; Zimmerman, Kurt L.; Gibo, Denise M.; Debinski, Waldemar (2015)This report describes the methodology, diagnostic yield, and adverse events (AE) associated with frame-based stereotactic brain biopsies (FBSB) obtained from 26 dogs with solitary forebrain lesions. Medical records were reviewed from dogs that underwent FBSB using two stereotactic headframes designed for use in small animals and compatible with computed tomographic (CT) and magnetic resonance (MR) imaging. Stereotactic plans were generated from MR and CT images using commercial software, and FBSB performed both with (14/26) and without intraoperative image guidance. Records were reviewed for diagnostic yield, defined as the proportion of biopsies producing a specific neuropathological diagnosis, AE associated with FBSB, and risk factors for the development of AE. Postprocedural AE were evaluated in 19/26 dogs that did not proceed to a therapeutic intervention immediately following biopsy. Biopsy targets included intra-axial telencephalic masses (24/26), one intra-axial diencephalic mass, and one extra-axial parasellar mass. The median target volume was 1.99 cm(3). No differences in patient, lesion, or outcome variables were observed between the two headframe systems used or between FBSB performed with or without intraoperative CT guidance. The diagnostic yield of FBSB was 94.6%. Needle placement error was a significant risk factor associated with procurement of non-diagnostic biopsy specimens. Gliomas were diagnosed in 24/26 dogs, and meningioma and granulomatous meningoencephalitis in 1 dog each. AE directly related to FBSB were observed in a total of 7/26 (27%) of dogs. Biopsy-associated clinical morbidity, manifesting as seizures and transient neurological deterioration, occurred in 3/19 (16%) of dogs. The case fatality rate was 5.2% (1/19 dogs), with death attributable to intracranial hemorrhage. FBSB using the described apparatus was relatively safe and effective at providing neuropathological diagnoses in dogs with focal forebrain lesions.
- High-frequency irreversible electroporation (H-FIRE) for non-thermal ablation without muscle contractionArena, Christopher B.; Sano, Michael B.; Rossmeisl, John H. Jr.; Caldwell, John L.; Garcia, Paulo A.; Rylander, M. Nichole; Davalos, Rafael V. (2011-11-21)Background Therapeutic irreversible electroporation (IRE) is an emerging technology for the non-thermal ablation of tumors. The technique involves delivering a series of unipolar electric pulses to permanently destabilize the plasma membrane of cancer cells through an increase in transmembrane potential, which leads to the development of a tissue lesion. Clinically, IRE requires the administration of paralytic agents to prevent muscle contractions during treatment that are associated with the delivery of electric pulses. This study shows that by applying high-frequency, bipolar bursts, muscle contractions can be eliminated during IRE without compromising the non-thermal mechanism of cell death. Methods A combination of analytical, numerical, and experimental techniques were performed to investigate high-frequency irreversible electroporation (H-FIRE). A theoretical model for determining transmembrane potential in response to arbitrary electric fields was used to identify optimal burst frequencies and amplitudes for in vivo treatments. A finite element model for predicting thermal damage based on the electric field distribution was used to design non-thermal protocols for in vivo experiments. H-FIRE was applied to the brain of rats, and muscle contractions were quantified via accelerometers placed at the cervicothoracic junction. MRI and histological evaluation was performed post-operatively to assess ablation. Results No visual or tactile evidence of muscle contraction was seen during H-FIRE at 250 kHz or 500 kHz, while all IRE protocols resulted in detectable muscle contractions at the cervicothoracic junction. H-FIRE produced ablative lesions in brain tissue that were characteristic in cellular morphology of non-thermal IRE treatments. Specifically, there was complete uniformity of tissue death within targeted areas, and a sharp transition zone was present between lesioned and normal brain. Conclusions H-FIRE is a feasible technique for non-thermal tissue ablation that eliminates muscle contractions seen in IRE treatments performed with unipolar electric pulses. Therefore, it has the potential to be performed clinically without the administration of paralytic agents.
- High-Frequency Irreversible Electroporation for Intracranial Meningioma: A Feasibility Study in a Spontaneous Canine Tumor ModelLatouche, Eduardo L.; Arena, Christopher B.; Ivey, Jill W.; Garcia, Paulo A.; Pancotto, Theresa E.; Pavlisko, Noah; Verbridge, Scott S.; Davalos, Rafael V.; Rossmeisl, John H. Jr. (Sage, 2018)High-frequency irreversible electroporation is a nonthermal method of tissue ablation that uses bursts of 0.5- to 2.0-microsecond bipolar electric pulses to permeabilize cell membranes and induce cell death. High-frequency irreversible electroporation has potential advantages for use in neurosurgery, including the ability to deliver pulses without inducing muscle contraction, inherent selectivity against malignant cells, and the capability of simultaneously opening the blood–brain barrier surrounding regions of ablation. Our objective was to determine whether high-frequency irreversible electroporation pulses capable of tumor ablation could be delivered to dogs with intracranial meningiomas. Three dogs with intracranial meningiomas were treated. Patient-specific treatment plans were generated using magnetic resonance imaging-based tissue segmentation, volumetric meshing, and finite element modeling. Following tumor biopsy, high-frequency irreversible electroporation pulses were stereotactically delivered in situ followed by tumor resection and morphologic and volumetric assessments of ablations. Clinical evaluations of treatment included pre- and posttreatment clinical, laboratory, and magnetic resonance imaging examinations and adverse event monitoring for 2 weeks posttreatment. High-frequency irreversible electroporation pulses were administered successfully in all patients. No adverse events directly attributable to high-frequency irreversible electroporation were observed. Individual ablations resulted in volumes of tumor necrosis ranging from 0.25 to 1.29 cm3. In one dog, nonuniform ablations were observed, with viable tumor cells remaining around foci of intratumoral mineralization. In conclusion, high-frequency irreversible electroporation pulses can be delivered to brain tumors, including areas adjacent to critical vasculature, and are capable of producing clinically relevant volumes of tumor ablation. Mineralization may complicate achievement of complete tumor ablation.
- High-frequency irreversible electroporation is an effective tumor ablation strategy that induces immunologic cell death and promotes systemic anti-tumor immunityRingel-Scaia, Veronica M.; Beitel-White, Natalie; Lorenzo, Melvin F.; Brock, Rebecca M.; Huie, Kathleen E.; Coutermarsh-Ott, Sheryl; Eden, Kristin; McDaniel, Dylan K.; Verbridge, Scott S.; Rossmeisl, John H. Jr.; Oestreich, Kenneth J.; Davalos, Rafael V.; Allen, Irving C. (2019-06)Background: Despite promising treatments for breast cancer, mortality rates remain high and treatments for metastatic disease are limited. High-frequency irreversible electroporation (H-FIRE) is a novel tumor ablation technique that utilizes high-frequency bipolar electric pulses to destabilize cancer cell membranes and induce cell death. However, there is currently a paucity of data pertaining to immune system activation following H-FIRE and other electroporation based tumor ablation techniques. Methods: Here, we utilized the mouse 4T1 mammary tumor model to evaluate H-FIRE treatment parameters on cancer progression and immune system activation in vitro and in vivo. Findings: H-FIRE effectively ablates the primary tumor and induces a pro-inflammatory shift in the tumor microenvironment. We further show that local treatment with H-FIRE significantly reduces 4T1 metastases. H-FIRE kills 4T1 cells through non-thermal mechanisms associated with necrosis and pyroptosis resulting in damage associated molecular pattern signaling in vitro and in vivo. Our data indicate that the level of tumor ablation correlates with increased activation of cellular immunity. Likewise, we show that the decrease in metastatic lesions is dependent on the intact immune system and H-FIRE generates 4T1 neoantigens that engage the adaptive immune system to significantly attenuate tumor progression. Interpretation: Cell death and tumor ablation following H-FIRE treatment activates the local innate immune system, which shifts the tumor microenvironment from an anti-inflammatory state to a pro-inflammatory state. The non-thermal damage to the cancer cells and increased innate immune system stimulation improves antigen presentation, resulting in the engagement of the adaptive immune system and improved systemic anti-tumor immunity. (C) 2019 The Authors. Published by Elsevier B.V.
- Improved Local and Systemic Anti-Tumor Efficacy for Irreversible Electroporation in Immunocompetent versus Immunodeficient MiceNeal, Robert E. II; Rossmeisl, John H. Jr.; Robertson, John L.; Arena, Christopher B.; Davis, Erica M.; Singh, Ravi N.; Stallings, Jonathan; Davalos, Rafael V. (PLOS, 2013-05-24)Irreversible electroporation (IRE) is a non-thermal focal ablation technique that uses a series of brief but intense electric pulses delivered into a targeted region of tissue, killing the cells by irrecoverably disrupting cellular membrane integrity. This study investigates if there is an improved local anti-tumor response in immunocompetent (IC) BALB/c versus immunodeficient (ID) nude mice, including the potential for a systemic protective effect against rechallenge. Subcutaneous murine renal carcinoma tumors were treated with an IRE pulsing protocol that used 60% of the predicted voltage required to invoke complete regressions in the ID mice. Tumors were followed for 34 days following treatment for 11 treated mice from each strain, and 7 controls from each strain. Mouse survival based on tumor burden and the progression-free disease period was substantially longer in the treated IC mice relative to the treated ID mice and sham controls for both strains. Treated IC mice were rechallenged with the same cell line 18 days after treatment, where growth of the second tumors was shown to be significantly reduced or prevented entirely. There was robust CD3+ cell infiltration in some treated BALB/C mice, with immunocytes focused at the transition between viable and dead tumor. There was no difference in the low immunocyte presence for untreated tumors, nude mice, and matrigel-only injections in both strains. These findings suggest IRE therapy may have greater therapeutic efficacy in immunocompetent patients than what has been suggested by immunodeficient models, and that IRE may invoke a systemic response beyond the targeted ablation region.
- «
- 1 (current)
- 2
- 3
- »