Gayle Johnson - Academia.edu (original) (raw)

Papers by Gayle Johnson

Research paper thumbnail of Forage-Associated Mycotoxicosis

Research paper thumbnail of Canine Distemper Virus*

Comparative Pathobiology of Viral Diseases, 2019

Research paper thumbnail of Albumin leakage into cerebrospinal fluid of dogs lethally infected with R252 canine distemper virus

Journal of Neuroimmunology, 1987

Cerebrospinal fluid (CSF) form nine lethally infected and three convalescent gnotobiotic dogs inf... more Cerebrospinal fluid (CSF) form nine lethally infected and three convalescent gnotobiotic dogs infected with the R252 strain of canine distemper virus (CDV) was evaluated prior to and following infection. Lethally infected dogs had a mean seven-fold increase in CSF albumin concentration compared to the preinoculation value, not present in dogs destined to survive. Immunochemical examination of tissue from these dogs revealed prominent perivascular localization of albumin. Examination of CSF cells demonstrated mild leukocytosis in both groups at the time when encephalopathic deaths occurred, with decreased lymphocyte percentages, particularly Thy-l-bearing lymphocytes, in lethally infected dogs. These dogs also had more extensive expression of viral antigens in CSF and peripheral blood leukocytes at the time of death than did surviving dogs, and failed to make antibody to viral antigens. The findings link terminal breakdown of the blood-brain barrier and extensive viral antigen expression in CSF leukocytes with experimental CDV infection resulting in death.

Research paper thumbnail of Neuronal ceroid-lipofuscinosis in a domestic cat: Clinical, morphological and immunohistochemical findings

Journal of Comparative Pathology, 1997

A 9-month-old domestic shorthair cat was humanely killed because of uncoordinated gait, myoclonus... more A 9-month-old domestic shorthair cat was humanely killed because of uncoordinated gait, myoclonus, seizures and reduced vision. Histological, immunohistochemical and ultrastructural examination revealed a neuronal storage disease consistent with neuronal ceroid-lipofuscinosis (NCL). Neurons contained Sudan black-and luxol fast blue-positive material which was autofluorescent. Immunohistochemically, the storage material was found to contain subunit c of mitochondrial ATP synthase, a protein recently recognized as the main component of the storage material in NCL. Ultrastructurally, the material consisted of curvilinear and fingerprint bodies, which are indicative of NCL.

Research paper thumbnail of The 14-3-3 Cerebrospinal Fluid Immunoassay Lacks Utility in the Diagnosis of Clinical Scrapie

Journal of Veterinary Diagnostic Investigation, Nov 1, 2001

This study determined whether the immunoassay for cerebrospinal fluid 14-3-3 protein concentratio... more This study determined whether the immunoassay for cerebrospinal fluid 14-3-3 protein concentration was sensitive and specific in the diagnosis of naturally occurring clinical scrapie in sheep. Cerebrospinal fluid was collected from 9 sheep with the confirmed diagnosis of scrapie. Additionally, cerebrospinal fluid was collected from 13 clinically normal sheep, which originated from a closely monitored flock with no history of scrapie. Sensitivity and specificity were calculated using standard epidemiological methods. Cerebrospinal fluid immunoassay results did not differ significantly between positive and negative sheep. Test sensitivity varied from 0.55 to 0.66, depending on the choice of test endpoint. Test specificity varied from 0.30 to 0.77, depending on the choice of test endpoint. The 14-3-3 cerebrospinal fluid immunoassay appears to have no value in the diagnosis of clinical scrapie in sheep.

Research paper thumbnail of Pathology in Practice

Journal of the American Veterinary Medical Association, 2017

Research paper thumbnail of Autologous cancer cell vaccination, adoptive T‐cell transfer, and interleukin‐2 administration results in long‐term survival for companion dogs with osteosarcoma

Journal of Veterinary Internal Medicine, 2020

BackgroundOsteosarcoma (OSA) in dogs is an aggressive bone tumor with frequent chemotherapy failu... more BackgroundOsteosarcoma (OSA) in dogs is an aggressive bone tumor with frequent chemotherapy failure and translational relevance for human health.Hypothesis/ObjectivesWe hypothesized that dogs with OSA could be treated safely by ex vivo activated T‐cells that were generated by autologous cancer vaccination and supported by interleukin‐2 (IL‐2) treatment with survival more than twice that reported for amputation alone.AnimalsOsteosarcoma‐bearing dogs (n = 14) were enrolled in a single‐arm prospective trial after complete staging before amputation. Four healthy dogs also were treated in a safety study.MethodsAutologous cancer cell vaccinations were administered intradermally and dogs underwent leukapheresis. Mononuclear cell products were stimulated ex vivo with a T‐cell‐activating agent. Activated product was transfused and 5 SC IL‐2 injections were administered q48h. Dogs were monitored for metastasis by thoracic radiography every 3 months.ResultsAutologous cancer cell vaccine and ac...

Research paper thumbnail of Reduced immune responsiveness and lymphoid depletion in mice infected with Ehrlichia risticii

Infection and Immunity, 1987

The histopathology of the thymus and spleen and the response of spleen cells to mitogenic stimuli... more The histopathology of the thymus and spleen and the response of spleen cells to mitogenic stimuli were evaluated in Sprague-Dawley CF-1 mice infected with Ehrlichia risticii. Intraperitoneal injection of 10(4) or 10(6) E. risticii-infected U-937 cells into mice resulted in 100% morbidity and partial mortality. Thymic atrophy became significant between 1 and 2 weeks postinfection and remained for the duration of the study. The atrophy appeared associated with antecedent destruction and rarefaction of lymphocytes, resulting in the loss of corticomedullary demarcation. Splenomegaly was prominent; significantly increased weights were detected 7 days postinfection. Histopathologic examination revealed rarefaction of lymphocytes around central arteries, the presence of necrotic debris in histiocytes, and replacement of erythropoiesis by granulopoiesis in the red pulp. Marked and acute reduction of in vitro proliferative responses of spleen cells to concanavalin A (ConA) and phytohemagglut...

Research paper thumbnail of Preferential immune response to virion surface glycoproteins by caprine arthritis-encephalitis virus-infected goats

Infection and Immunity, 1983

Six months after inoculation with caprine arthritis-encephalitis virus, the serum and synovial fl... more Six months after inoculation with caprine arthritis-encephalitis virus, the serum and synovial fluid of virus-infected goats had antibodies to [35S]methionine-labeled viral proteins with apparent molecular weights of 125,000, 90,000, 28,000, and 15,000. The 125,000-, 90,000-, and 15,000-molecular-weight methionine-labeled proteins were identified as virion surface glycoproteins by lactoperoxidase iodination and galactose oxidase-boro[3H]hydride reduction labeling techniques. Radioimmunoassay antibody titers to purified p28, the most abundant viral structural protein, averaged 1:182 in synovial fluid and 1:67 in serum 6 months after inoculation. High dilutions of serum and synovial fluid reacted with gp90 and gp125 electroblotted onto nitrocellulose paper from polyacrylamide gels. Anti-gp90 activity was detected at dilutions with an immunoglobulin G content of 0.02 to 11 micrograms, whereas antibody to p28, when detectable on Western blots, was present in samples with an immunoglobul...

Research paper thumbnail of Therapeutic value of 21-aminosteroid U74389F in acute spinal cord injury

Neurological Research, 1993

The effect of bolus injections of 21-aminosteroid U74389F after an acute spinal cord compression ... more The effect of bolus injections of 21-aminosteroid U74389F after an acute spinal cord compression trauma in rats was studied. Cortical somatosensory evoked potentials (CSEPs) were recorded before and after a weight-induced injury of 120 g and monitored up to five hours post-injury. All U74389F treatments were given as i.v. bolus injections of 15, 7.5, and 3.75 mg kg-1 at 1, 2, 3 h after the trauma, respectively. The CSEPs were abolished immediately after the injury in the control and treated animals. The majority of the treated animals (88.8%) demonstrated a return of the CSEPs within the second hour post-injury. In contrast, the animals in the control group showed only 44.4% recovery at this time period. At three hours post-injury, U74389F-treated animals (n = 18) showed a full recovery (100%) while the recovery rate remained at 44.4% for the control animals. We conclude that the bolus administration of U74389F one hour after injury facilitates the return of the spinal cord function as measured by the CSEPs in this compression model of acute spinal cord trauma.

Research paper thumbnail of Pretreatment with NMDA receptor antagonist MK801 improves neurophysiological outcome after an acute spinal cord injury

Neurological Research, 1996

The post-traumatic release of excitatory amino acids (EAA) and their actions on N-methyl-D-aspart... more The post-traumatic release of excitatory amino acids (EAA) and their actions on N-methyl-D-aspartate (NMDA) receptors plays a major role in the spinal cord secondary injury process. The neuronal damage caused by the release of EAA may be reduced by NMDA-receptor channel blockers. To investigate the involvement of NMDA receptors in spinal cord injury (SCI), we pretreated animals with the noncompetitive NMDA antagonist MK801 (1.0 mg kg-1) before a compressive acute SCI. Pretreated animals with MK801 significantly (p = 0.038) improved the recovery of function as measured by evoked potential activities. Morphologically, specimens from rats treated with MK801 were characterized by milder and more localized hemorrhage in the gray matter. Immunohistochemical staining for glial fibrillary acidic protein (GFAP) and neurofilament (NF) histochemistry showed leakage of these antigens in traumatized cord while characteristic staining of astrocytes and neurons and their processes was observed in morphologically preserved tissue. The loss of NF immunoreactivity was reduced by MK801 treatment.

Research paper thumbnail of Effects of methylprednisolone and MK-801 on functional recovery after experimental chronic spinal cord injury

Spinal Cord, 2000

Study design: An experimental study was conducted to evaluate the eects of methylprednisolone and... more Study design: An experimental study was conducted to evaluate the eects of methylprednisolone and MK-801 after the compressive injury of spinal cord in rats. Objectives: To investigate the eect of methylprednisolone and non-competitive NMDA antagonist MK-801 in long-term functional outcome after spinal cord injury (SCI). Methods: A randomized group A of Sprague-Dawley rats were treated with MK-801 (1.0 mg/kg, n=10; Group A) after a compression injury. A group of methylprednisolone (MP)-treated (30 mg/kg, n=10; Group B) and non-treated animals (n=9; Group C) were included for comparison. The functional motor outcome such as inclined plane (IP), toe spreading re¯ex (TSR), and modi®ed Tarlov scale (TS) were measured in each animal at regular time points up to 8 weeks post-treatment. Histologically the injury site was scored in four groups and immunohistochemically Wallerian Degeneration (WD), astrocytosis and expression of b-amyloid protein was identi®ed. Results: In examining the IP data, no signi®cant dierence was recognized between the group means (P-value40.5). For the TSR, there were no dierences in the group responses. For the TS, the dierences were not statistically signi®cant. Only group B showed signi®cance in cavitation scores compared to group A (P40.0094), WD was signi®cantly dierent than group C (P40.03), astrocytosis was signi®cantly higher than group A (P40.001) and modest presence of b-amyloid protein. Conclusion: Our data indicate that one time bolus administration of MK-801 lacks any signi®cant eect on axonal function in chronically injured rats. Daily bolus administration of MP at 30 mg/kg also did not ensure a better functional outcome. Immunohistochemically we have been able to show signi®cant dierences in WD, astrocytosis and small insigni®cant changes in b-amyloid protein.

Research paper thumbnail of Subclinical hypocalcemia, plasma biochemical parameters, lipid metabolism, postpartum disease, and fertility in postparturient dairy cows

Journal of dairy science, 2013

A study was conducted to evaluate the potential association between Ca status at calving and post... more A study was conducted to evaluate the potential association between Ca status at calving and postpartum energy balance, liver lipid infiltration, disease occurrence, milk yield and quality parameters, and fertility in Holstein cows. One hundred cows were assigned to 1 of 2 groups based on whole-blood ionized Ca concentration ([iCa]) on the day of calving [d 0; hypocalcemic [iCa] <1.0 mmol/L (n=51); normocalcemic [iCa] ≥ 1.0 mmol/L (n=49)]. Cows were blocked based on calving date and parity. Blood samples were collected approximately 14 d from expected calving date (d -14), the day of calving (d 0), and on d 3, 7, 14, 21, and 35 postpartum for measurement of plasma nonesterified fatty acid, iCa, total Ca, glucose, and total and direct bilirubin concentrations, and plasma aspartate aminotransferase and gamma glutamyl transferase activities. Liver biopsies were obtained from a subset of cows on d 0, 7, and 35 for quantification of lipid content. Milk samples were collected on d 3, 7...

Research paper thumbnail of Congenital megalourethra in a male Charolais calf

The Canadian veterinary journal. La revue vétérinaire canadienne, 1992

A ten-day-old Charolais bull calf that weighed 45 kg was admitted to the

Research paper thumbnail of Loss of absorptive capacity for sodium and chloride in the colon causes diarrhoea in Potomac horse fever

Research in Veterinary Science, 1992

Ehrlichia risticii, an obligate intracellular bacterium in the family Rickettsiaceae, causes Poto... more Ehrlichia risticii, an obligate intracellular bacterium in the family Rickettsiaceae, causes Potomac horse fever which is often associated with severe watery diarrhoea. The mechanism of the diarrhoea is unknown. The aim of this study was to determine whether sodium and chloride transport, morphology and cyclic adenosine 3', 5'-monophosphate (cyclic AMP) content of colonic mucosa was altered in E risticii-infected horses. Mucosa-submucosa sheets from the large and small colon of nine infected and seven to nine uninfected horses were set up in Ussing chambers for measurement of short-circuit current and transepithelia122Na and 36Ci fluxes. Uninfected tissues absorbed both sodium and chloride whereas absorption of sodium and chloride was abolished in infected tissues. Bethanechol and histamine evoked a concentration-dependent increase in short-circuit current in both groups, but the responses were attenuated at all concentrations in infected horses. Slight focal degeneration of colonic epithelial cells and loss of microvilli from glandular epithelial cells occurred in infected horses. There was a significant increase in cyclic AMP content in colonic mucosa of infected animals. The results suggest that E risticiiinfection induces focal microscopic degeneration of epithelial cells and an increase in intraceHular cyclic AMP in colonic mucosa. These alterations are associated with malabsorption of sodium and chloride and could cause diarrhoea. EHRLICHIA risticii, a member of the family Rickettsiaceae, is an obligate, intracellular bacterium which infects blood monocytes in the

Research paper thumbnail of Plaque identification of strand-forming canine distemper virus by staphylococcal Protein A-mediated reverse passive haemadsorption

Journal of Virological Methods, 1985

The R252 neurotropic isolate of canine distemper virus (CDV) produces cytopathic effects (CPE) do... more The R252 neurotropic isolate of canine distemper virus (CDV) produces cytopathic effects (CPE) dominated by strand formation rather than by the formation of multinucleate giant cells. The lack of well-defined CPE and consequent rapid spread of infection throughout the cell monolayer has hindered plaque purification of this virus by conventional methods. However, the useofan immunologicaldetection system which utilizes binding of hyperimmune dog serum to virus-infected cells, followed by the identification of those sites by staphylococcal Protein A-coupled sheep red blood cells (reverse passive haemadsorption) allowed infected foci in cell monolayers to be detected as early as 4days after infection, coincident with the appearance of the first immunofluorescently identified viral foci. Foci of haemadsorption were specific to sites of CDV infection as demonstrated by blocking experiments. Material recovered from the plaques was successful in infecting Vero cells. Thus, immunologically mediated adsorption of Protein A coupled red blood cells can be used to identify and isolate foci of viral infection which exhibit minimal or no viral CPE without destroying viral replicative ability. plaque assay morbillivirus canine distemper virus staphylococcal Protein A heamadsorption

Research paper thumbnail of Caprine retroviral encephalitis in previously infected and specific pathogen-free goats

Journal of Neuroimmunology, 1987

Research paper thumbnail of Ultrastructure of junctional epidermolysis bullosa in Belgian foals

Journal of Comparative Pathology, 1988

liltrastructural rxamination of a m~chanobullous disease of probable hercditar); nature in Belgia... more liltrastructural rxamination of a m~chanobullous disease of probable hercditar); nature in Belgian foals, confirmed light microscopic findings that separation of the dermtrepidermal junction occurred through the lamina lucida of the basement membrane, leaving the intact lamina drnsa adherent to the dermis and the plasmalemma of-the basal epithelial cells intact. 'I'hc Ioc.ation of the cleft and the presence of small hemidesmosomes in adjacent illt;lct skin arr additional characteristics which makr this condition sim'ilar to junctional epidermolysis bullosa of man.

Research paper thumbnail of Thoracic involvement from osteosarcoma: typical and atypical CT manifestations

American Journal of Roentgenology, 1997

Research paper thumbnail of Case Reports: Disseminated Chlorellosis in a Dog

Veterinary Pathology, 2009

An adult dog with ataxia and a lingual mass, previously diagnosed as protothecosis, was euthanize... more An adult dog with ataxia and a lingual mass, previously diagnosed as protothecosis, was euthanized. At the postmortem examination, the lingual mass, regions of the lungs and hilar lymph nodes, liver, mesenteric and sublumbar lymph nodes, and spinal meninges had pronounced green discoloration. Histologically, pyogranulomatous inflammation and algal organisms were found in the tongue, spinal meninges, hilar and mesenteric lymph nodes, liver, and lung. The algae had cell walls positive for periodic acid-Schiff and cytoplasmic granules. Ultrastructurally, the algae had a well-defined cell wall, stacks of grana and thylakoid membrane, and dense bodies, typical of starch granules. The organisms were identified as Chlorella, a green alga, based on the results of histochemistical and electron microscopic examination. To the author's knowledge this is the first report of disseminated Chlorella infection and the first report in a companion animal.

Research paper thumbnail of Forage-Associated Mycotoxicosis

Research paper thumbnail of Canine Distemper Virus*

Comparative Pathobiology of Viral Diseases, 2019

Research paper thumbnail of Albumin leakage into cerebrospinal fluid of dogs lethally infected with R252 canine distemper virus

Journal of Neuroimmunology, 1987

Cerebrospinal fluid (CSF) form nine lethally infected and three convalescent gnotobiotic dogs inf... more Cerebrospinal fluid (CSF) form nine lethally infected and three convalescent gnotobiotic dogs infected with the R252 strain of canine distemper virus (CDV) was evaluated prior to and following infection. Lethally infected dogs had a mean seven-fold increase in CSF albumin concentration compared to the preinoculation value, not present in dogs destined to survive. Immunochemical examination of tissue from these dogs revealed prominent perivascular localization of albumin. Examination of CSF cells demonstrated mild leukocytosis in both groups at the time when encephalopathic deaths occurred, with decreased lymphocyte percentages, particularly Thy-l-bearing lymphocytes, in lethally infected dogs. These dogs also had more extensive expression of viral antigens in CSF and peripheral blood leukocytes at the time of death than did surviving dogs, and failed to make antibody to viral antigens. The findings link terminal breakdown of the blood-brain barrier and extensive viral antigen expression in CSF leukocytes with experimental CDV infection resulting in death.

Research paper thumbnail of Neuronal ceroid-lipofuscinosis in a domestic cat: Clinical, morphological and immunohistochemical findings

Journal of Comparative Pathology, 1997

A 9-month-old domestic shorthair cat was humanely killed because of uncoordinated gait, myoclonus... more A 9-month-old domestic shorthair cat was humanely killed because of uncoordinated gait, myoclonus, seizures and reduced vision. Histological, immunohistochemical and ultrastructural examination revealed a neuronal storage disease consistent with neuronal ceroid-lipofuscinosis (NCL). Neurons contained Sudan black-and luxol fast blue-positive material which was autofluorescent. Immunohistochemically, the storage material was found to contain subunit c of mitochondrial ATP synthase, a protein recently recognized as the main component of the storage material in NCL. Ultrastructurally, the material consisted of curvilinear and fingerprint bodies, which are indicative of NCL.

Research paper thumbnail of The 14-3-3 Cerebrospinal Fluid Immunoassay Lacks Utility in the Diagnosis of Clinical Scrapie

Journal of Veterinary Diagnostic Investigation, Nov 1, 2001

This study determined whether the immunoassay for cerebrospinal fluid 14-3-3 protein concentratio... more This study determined whether the immunoassay for cerebrospinal fluid 14-3-3 protein concentration was sensitive and specific in the diagnosis of naturally occurring clinical scrapie in sheep. Cerebrospinal fluid was collected from 9 sheep with the confirmed diagnosis of scrapie. Additionally, cerebrospinal fluid was collected from 13 clinically normal sheep, which originated from a closely monitored flock with no history of scrapie. Sensitivity and specificity were calculated using standard epidemiological methods. Cerebrospinal fluid immunoassay results did not differ significantly between positive and negative sheep. Test sensitivity varied from 0.55 to 0.66, depending on the choice of test endpoint. Test specificity varied from 0.30 to 0.77, depending on the choice of test endpoint. The 14-3-3 cerebrospinal fluid immunoassay appears to have no value in the diagnosis of clinical scrapie in sheep.

Research paper thumbnail of Pathology in Practice

Journal of the American Veterinary Medical Association, 2017

Research paper thumbnail of Autologous cancer cell vaccination, adoptive T‐cell transfer, and interleukin‐2 administration results in long‐term survival for companion dogs with osteosarcoma

Journal of Veterinary Internal Medicine, 2020

BackgroundOsteosarcoma (OSA) in dogs is an aggressive bone tumor with frequent chemotherapy failu... more BackgroundOsteosarcoma (OSA) in dogs is an aggressive bone tumor with frequent chemotherapy failure and translational relevance for human health.Hypothesis/ObjectivesWe hypothesized that dogs with OSA could be treated safely by ex vivo activated T‐cells that were generated by autologous cancer vaccination and supported by interleukin‐2 (IL‐2) treatment with survival more than twice that reported for amputation alone.AnimalsOsteosarcoma‐bearing dogs (n = 14) were enrolled in a single‐arm prospective trial after complete staging before amputation. Four healthy dogs also were treated in a safety study.MethodsAutologous cancer cell vaccinations were administered intradermally and dogs underwent leukapheresis. Mononuclear cell products were stimulated ex vivo with a T‐cell‐activating agent. Activated product was transfused and 5 SC IL‐2 injections were administered q48h. Dogs were monitored for metastasis by thoracic radiography every 3 months.ResultsAutologous cancer cell vaccine and ac...

Research paper thumbnail of Reduced immune responsiveness and lymphoid depletion in mice infected with Ehrlichia risticii

Infection and Immunity, 1987

The histopathology of the thymus and spleen and the response of spleen cells to mitogenic stimuli... more The histopathology of the thymus and spleen and the response of spleen cells to mitogenic stimuli were evaluated in Sprague-Dawley CF-1 mice infected with Ehrlichia risticii. Intraperitoneal injection of 10(4) or 10(6) E. risticii-infected U-937 cells into mice resulted in 100% morbidity and partial mortality. Thymic atrophy became significant between 1 and 2 weeks postinfection and remained for the duration of the study. The atrophy appeared associated with antecedent destruction and rarefaction of lymphocytes, resulting in the loss of corticomedullary demarcation. Splenomegaly was prominent; significantly increased weights were detected 7 days postinfection. Histopathologic examination revealed rarefaction of lymphocytes around central arteries, the presence of necrotic debris in histiocytes, and replacement of erythropoiesis by granulopoiesis in the red pulp. Marked and acute reduction of in vitro proliferative responses of spleen cells to concanavalin A (ConA) and phytohemagglut...

Research paper thumbnail of Preferential immune response to virion surface glycoproteins by caprine arthritis-encephalitis virus-infected goats

Infection and Immunity, 1983

Six months after inoculation with caprine arthritis-encephalitis virus, the serum and synovial fl... more Six months after inoculation with caprine arthritis-encephalitis virus, the serum and synovial fluid of virus-infected goats had antibodies to [35S]methionine-labeled viral proteins with apparent molecular weights of 125,000, 90,000, 28,000, and 15,000. The 125,000-, 90,000-, and 15,000-molecular-weight methionine-labeled proteins were identified as virion surface glycoproteins by lactoperoxidase iodination and galactose oxidase-boro[3H]hydride reduction labeling techniques. Radioimmunoassay antibody titers to purified p28, the most abundant viral structural protein, averaged 1:182 in synovial fluid and 1:67 in serum 6 months after inoculation. High dilutions of serum and synovial fluid reacted with gp90 and gp125 electroblotted onto nitrocellulose paper from polyacrylamide gels. Anti-gp90 activity was detected at dilutions with an immunoglobulin G content of 0.02 to 11 micrograms, whereas antibody to p28, when detectable on Western blots, was present in samples with an immunoglobul...

Research paper thumbnail of Therapeutic value of 21-aminosteroid U74389F in acute spinal cord injury

Neurological Research, 1993

The effect of bolus injections of 21-aminosteroid U74389F after an acute spinal cord compression ... more The effect of bolus injections of 21-aminosteroid U74389F after an acute spinal cord compression trauma in rats was studied. Cortical somatosensory evoked potentials (CSEPs) were recorded before and after a weight-induced injury of 120 g and monitored up to five hours post-injury. All U74389F treatments were given as i.v. bolus injections of 15, 7.5, and 3.75 mg kg-1 at 1, 2, 3 h after the trauma, respectively. The CSEPs were abolished immediately after the injury in the control and treated animals. The majority of the treated animals (88.8%) demonstrated a return of the CSEPs within the second hour post-injury. In contrast, the animals in the control group showed only 44.4% recovery at this time period. At three hours post-injury, U74389F-treated animals (n = 18) showed a full recovery (100%) while the recovery rate remained at 44.4% for the control animals. We conclude that the bolus administration of U74389F one hour after injury facilitates the return of the spinal cord function as measured by the CSEPs in this compression model of acute spinal cord trauma.

Research paper thumbnail of Pretreatment with NMDA receptor antagonist MK801 improves neurophysiological outcome after an acute spinal cord injury

Neurological Research, 1996

The post-traumatic release of excitatory amino acids (EAA) and their actions on N-methyl-D-aspart... more The post-traumatic release of excitatory amino acids (EAA) and their actions on N-methyl-D-aspartate (NMDA) receptors plays a major role in the spinal cord secondary injury process. The neuronal damage caused by the release of EAA may be reduced by NMDA-receptor channel blockers. To investigate the involvement of NMDA receptors in spinal cord injury (SCI), we pretreated animals with the noncompetitive NMDA antagonist MK801 (1.0 mg kg-1) before a compressive acute SCI. Pretreated animals with MK801 significantly (p = 0.038) improved the recovery of function as measured by evoked potential activities. Morphologically, specimens from rats treated with MK801 were characterized by milder and more localized hemorrhage in the gray matter. Immunohistochemical staining for glial fibrillary acidic protein (GFAP) and neurofilament (NF) histochemistry showed leakage of these antigens in traumatized cord while characteristic staining of astrocytes and neurons and their processes was observed in morphologically preserved tissue. The loss of NF immunoreactivity was reduced by MK801 treatment.

Research paper thumbnail of Effects of methylprednisolone and MK-801 on functional recovery after experimental chronic spinal cord injury

Spinal Cord, 2000

Study design: An experimental study was conducted to evaluate the eects of methylprednisolone and... more Study design: An experimental study was conducted to evaluate the eects of methylprednisolone and MK-801 after the compressive injury of spinal cord in rats. Objectives: To investigate the eect of methylprednisolone and non-competitive NMDA antagonist MK-801 in long-term functional outcome after spinal cord injury (SCI). Methods: A randomized group A of Sprague-Dawley rats were treated with MK-801 (1.0 mg/kg, n=10; Group A) after a compression injury. A group of methylprednisolone (MP)-treated (30 mg/kg, n=10; Group B) and non-treated animals (n=9; Group C) were included for comparison. The functional motor outcome such as inclined plane (IP), toe spreading re¯ex (TSR), and modi®ed Tarlov scale (TS) were measured in each animal at regular time points up to 8 weeks post-treatment. Histologically the injury site was scored in four groups and immunohistochemically Wallerian Degeneration (WD), astrocytosis and expression of b-amyloid protein was identi®ed. Results: In examining the IP data, no signi®cant dierence was recognized between the group means (P-value40.5). For the TSR, there were no dierences in the group responses. For the TS, the dierences were not statistically signi®cant. Only group B showed signi®cance in cavitation scores compared to group A (P40.0094), WD was signi®cantly dierent than group C (P40.03), astrocytosis was signi®cantly higher than group A (P40.001) and modest presence of b-amyloid protein. Conclusion: Our data indicate that one time bolus administration of MK-801 lacks any signi®cant eect on axonal function in chronically injured rats. Daily bolus administration of MP at 30 mg/kg also did not ensure a better functional outcome. Immunohistochemically we have been able to show signi®cant dierences in WD, astrocytosis and small insigni®cant changes in b-amyloid protein.

Research paper thumbnail of Subclinical hypocalcemia, plasma biochemical parameters, lipid metabolism, postpartum disease, and fertility in postparturient dairy cows

Journal of dairy science, 2013

A study was conducted to evaluate the potential association between Ca status at calving and post... more A study was conducted to evaluate the potential association between Ca status at calving and postpartum energy balance, liver lipid infiltration, disease occurrence, milk yield and quality parameters, and fertility in Holstein cows. One hundred cows were assigned to 1 of 2 groups based on whole-blood ionized Ca concentration ([iCa]) on the day of calving [d 0; hypocalcemic [iCa] <1.0 mmol/L (n=51); normocalcemic [iCa] ≥ 1.0 mmol/L (n=49)]. Cows were blocked based on calving date and parity. Blood samples were collected approximately 14 d from expected calving date (d -14), the day of calving (d 0), and on d 3, 7, 14, 21, and 35 postpartum for measurement of plasma nonesterified fatty acid, iCa, total Ca, glucose, and total and direct bilirubin concentrations, and plasma aspartate aminotransferase and gamma glutamyl transferase activities. Liver biopsies were obtained from a subset of cows on d 0, 7, and 35 for quantification of lipid content. Milk samples were collected on d 3, 7...

Research paper thumbnail of Congenital megalourethra in a male Charolais calf

The Canadian veterinary journal. La revue vétérinaire canadienne, 1992

A ten-day-old Charolais bull calf that weighed 45 kg was admitted to the

Research paper thumbnail of Loss of absorptive capacity for sodium and chloride in the colon causes diarrhoea in Potomac horse fever

Research in Veterinary Science, 1992

Ehrlichia risticii, an obligate intracellular bacterium in the family Rickettsiaceae, causes Poto... more Ehrlichia risticii, an obligate intracellular bacterium in the family Rickettsiaceae, causes Potomac horse fever which is often associated with severe watery diarrhoea. The mechanism of the diarrhoea is unknown. The aim of this study was to determine whether sodium and chloride transport, morphology and cyclic adenosine 3', 5'-monophosphate (cyclic AMP) content of colonic mucosa was altered in E risticii-infected horses. Mucosa-submucosa sheets from the large and small colon of nine infected and seven to nine uninfected horses were set up in Ussing chambers for measurement of short-circuit current and transepithelia122Na and 36Ci fluxes. Uninfected tissues absorbed both sodium and chloride whereas absorption of sodium and chloride was abolished in infected tissues. Bethanechol and histamine evoked a concentration-dependent increase in short-circuit current in both groups, but the responses were attenuated at all concentrations in infected horses. Slight focal degeneration of colonic epithelial cells and loss of microvilli from glandular epithelial cells occurred in infected horses. There was a significant increase in cyclic AMP content in colonic mucosa of infected animals. The results suggest that E risticiiinfection induces focal microscopic degeneration of epithelial cells and an increase in intraceHular cyclic AMP in colonic mucosa. These alterations are associated with malabsorption of sodium and chloride and could cause diarrhoea. EHRLICHIA risticii, a member of the family Rickettsiaceae, is an obligate, intracellular bacterium which infects blood monocytes in the

Research paper thumbnail of Plaque identification of strand-forming canine distemper virus by staphylococcal Protein A-mediated reverse passive haemadsorption

Journal of Virological Methods, 1985

The R252 neurotropic isolate of canine distemper virus (CDV) produces cytopathic effects (CPE) do... more The R252 neurotropic isolate of canine distemper virus (CDV) produces cytopathic effects (CPE) dominated by strand formation rather than by the formation of multinucleate giant cells. The lack of well-defined CPE and consequent rapid spread of infection throughout the cell monolayer has hindered plaque purification of this virus by conventional methods. However, the useofan immunologicaldetection system which utilizes binding of hyperimmune dog serum to virus-infected cells, followed by the identification of those sites by staphylococcal Protein A-coupled sheep red blood cells (reverse passive haemadsorption) allowed infected foci in cell monolayers to be detected as early as 4days after infection, coincident with the appearance of the first immunofluorescently identified viral foci. Foci of haemadsorption were specific to sites of CDV infection as demonstrated by blocking experiments. Material recovered from the plaques was successful in infecting Vero cells. Thus, immunologically mediated adsorption of Protein A coupled red blood cells can be used to identify and isolate foci of viral infection which exhibit minimal or no viral CPE without destroying viral replicative ability. plaque assay morbillivirus canine distemper virus staphylococcal Protein A heamadsorption

Research paper thumbnail of Caprine retroviral encephalitis in previously infected and specific pathogen-free goats

Journal of Neuroimmunology, 1987

Research paper thumbnail of Ultrastructure of junctional epidermolysis bullosa in Belgian foals

Journal of Comparative Pathology, 1988

liltrastructural rxamination of a m~chanobullous disease of probable hercditar); nature in Belgia... more liltrastructural rxamination of a m~chanobullous disease of probable hercditar); nature in Belgian foals, confirmed light microscopic findings that separation of the dermtrepidermal junction occurred through the lamina lucida of the basement membrane, leaving the intact lamina drnsa adherent to the dermis and the plasmalemma of-the basal epithelial cells intact. 'I'hc Ioc.ation of the cleft and the presence of small hemidesmosomes in adjacent illt;lct skin arr additional characteristics which makr this condition sim'ilar to junctional epidermolysis bullosa of man.

Research paper thumbnail of Thoracic involvement from osteosarcoma: typical and atypical CT manifestations

American Journal of Roentgenology, 1997

Research paper thumbnail of Case Reports: Disseminated Chlorellosis in a Dog

Veterinary Pathology, 2009

An adult dog with ataxia and a lingual mass, previously diagnosed as protothecosis, was euthanize... more An adult dog with ataxia and a lingual mass, previously diagnosed as protothecosis, was euthanized. At the postmortem examination, the lingual mass, regions of the lungs and hilar lymph nodes, liver, mesenteric and sublumbar lymph nodes, and spinal meninges had pronounced green discoloration. Histologically, pyogranulomatous inflammation and algal organisms were found in the tongue, spinal meninges, hilar and mesenteric lymph nodes, liver, and lung. The algae had cell walls positive for periodic acid-Schiff and cytoplasmic granules. Ultrastructurally, the algae had a well-defined cell wall, stacks of grana and thylakoid membrane, and dense bodies, typical of starch granules. The organisms were identified as Chlorella, a green alga, based on the results of histochemistical and electron microscopic examination. To the author's knowledge this is the first report of disseminated Chlorella infection and the first report in a companion animal.