Lori Gregorash

National Research Council Canada, Ottawa, Ontario, Canada

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Publications (10)27.88 Total impact

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    ABSTRACT: We monitored the development of hepatocellular carcinoma due to chronic infection with woodchuck hepatitis virus by using monthly serum samples, physical examination, and magnetic resonance imaging. The same woodchucks can be imaged repeatedly over a 1-y period by allowing the animals to recover after each experiment, thus reducing the number of animals required without compromising the quality of the data obtained. Age- and sex-matched uninfected control (n = 5) and chronically infected (n = 5) woodchucks were group-housed according to sex and infection status. Woodchucks were anaesthetized using an inhalation anesthetic (isoflurane) without premedication. During imaging, we regularly monitored heart rate, body temperature, and respiration. Tumor growth was observed using MRI, whereas the extent of hepatocyte injury was followed using serum liver enzymes. Elevated serum gamma glutamyltransferase and aspartate aminotransferase levels indicated hepatocyte injury due to tumor growth. On magnetic resonance images, the liver should appear as a well-defined, homogenous organ with defined regions of hyperintensities from larger blood vessels. Within tumor nodules, the liver appeared irregularly shaped, having heterogeneous intensity from unregulated cellular proliferation. Changes in tumor size can be monitored by imaging infected woodchucks on a regular basis. Using the imaging techniques we describe, the development of hepatocellular carcinoma can be visualized using magnetic resonance imaging, correlated to serum tests, and compared with the results from uninfected control woodchucks, thereby improving the understanding of the disease progress.
    Journal of the American Association for Laboratory Animal Science: JAALAS 04/2006; 45(2):26-30. · 1.15 Impact Factor
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    ABSTRACT: Purpose:To examine neuronal activation in the spinal cord due to secondary hyperalgesia resulting from intrajoint capsaicin injection, and the effect of physiotherapy manipulation, using functional magnetic resonance imaging (fMRI), in -chloralose anesthetized rats.Materials and Methods:FMRI of the rat lumbar spinal cord was performed at 9.4 Tesla. Stimuli included injection of 25 μL of capsaicin (128 μg/mL in 7.5% dimethyl sulfoxide [DMSO]) into the right forepaw or 75 μL into the right ankle joint followed by a light touch stimulus, with and without physiotherapy manipulation.Results:Activation of pain areas of the spinal cord (dorsal horn) was found in all animals after injection of capsaicin into the plantar surface of the rat hindpaw and ankle joint. Overlay maps depicting activations and deactivations showed significant reproducibility between experiments. Greater overlay of activations were observed for intrajoint compared to intradermal capsaicin injection. The distribution of activations after stimulation of the hindpaw using a light touch stimulus was somewhat more varied; activation of the dorsal horn was evident, with greater overlap resulting when joint mobilization was not performed.Conclusion:Results suggest a trend toward decreased areas of activation in the spinal cord associated with pain, as a result of hyperalgesia, following physiotherapy joint mobilization. J. Magn. Reson. Imaging 2003;18:152–159. © 2003 Wiley-Liss, Inc.
    Journal of Magnetic Resonance Imaging 07/2003; 18(2):152 - 159. · 2.57 Impact Factor
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    ABSTRACT: MRTE/ANRE; ; ;
    Magnetic Resonance Imaging 07/2003; · 2.06 Impact Factor
  • Journal of Molecular and Cellular Cardiology - J MOL CELL CARDIOL. 01/2001; 33(6).
  • Journal of Molecular and Cellular Cardiology - J MOL CELL CARDIOL. 01/2001; 33(6).
  • Journal of Molecular and Cellular Cardiology - J MOL CELL CARDIOL. 01/2001; 33(6).
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    ABSTRACT: ANRE/BIOS/INFO/MRTE; ; ;
    Circulation 12/1997; · 15.20 Impact Factor
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    ABSTRACT: Four experimental protocols were carried out to assess the ability of esmolol to induce and maintain reversible cardiac arrest under continuous normothermic (37 degrees C) perfusion. In the first protocol, 8 perfused rat hearts were subjected to 20, 60, 90, and 120 minutes of esmolol arrest, after which positive and negative first derivative of pressure, heart rate, left ventricular developed pressure, and left ventricular end-diastolic pressure were evaluated. Arrest was achieved 45 to 60 seconds after beginning the infusion of esmolol. Mechanical arrest was achieved before electrical arrest. In the second protocol, dose-response curves were obtained using isolated (Langendorff) rat and rabbit (n = 6) hearts. The concentrations of esmolol varied from 0.084 to 6.7 mmol/L and from 0.12 to 1.45 mmol/L in the rat and rabbit heart experiments, respectively. In the third protocol, the effects of 20 minutes of normothermic (37 degrees C) ischemia on the function of isolated rat hearts perfused with esmolol-containing Krebs solution were compared with those using high-potassium (25 mmol/L) Krebs solution. Group A subjects (n = 9) received the ischemic injury after being perfused (and arrested) for 20 minutes with either esmolol or potassium (KCl, 25 mmol/L). Group B subjects (n = 10) received the same ischemic insult before being perfused with either esmolol or potassium. Esmolol-treated hearts showed better recovery than those receiving potassium, in terms of +/- dP/dt (p < 0.01), left ventricular systolic pressure (p < 0.01), and left ventricular developed pressure (p < 0.009). Finally, the fourth protocol was done to evaluate the effects of esmolol in a clinically relevant experimental model. Pigs were divided into esmolol (n = 6) and potassium (n = 5) groups and subjected to normothermic cardiopulmonary bypass and a 1-hour period of cardiac arrest. Twenty minutes after stopping infusion of the cardioplegic agents, all animals were weaned off bypass. There were no statistically significant differences between the groups. Esmolol hydrochloride can be used as effectively as potassium for inducing and maintaining predictable and reversible cardiac arrest during normothermic cardiac operations.
    The Annals of Thoracic Surgery 04/1997; 63(3):721-7. · 3.45 Impact Factor
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    ABSTRACT: Background. Four experimental protocols were carried out to assess the ability of esmolol to induce and maintain reversible cardiac arrest under continuous normothermic (37oC) perfusion.Methods and Results. In the first protocol, 8 perfused rat hearts were subjected to 20, 60, 90, and 120 minutes of esmolol arrest, after which positive and negative first derivative of pressure, heart rate, left ventricular developed pressure, and left ventricular end-diastolic pressure were evaluated. Arrest was achieved 45 to 60 seconds after beginning the infusion of esmolol. Mechanical arrest was achieved before electrical arrest. In the second protocol, dose-response curves were obtained using isolated (Langendorff) rat and rabbit (n = 6) hearts. The concentrations of esmolol varied from 0.084 to 6.7 mmol/L and from 0.12 to 1.45 mmol/L in the rat and rabbit heart experiments, respectively. In the third protocol, the effects of 20 minutes of normothermic (37oC) ischemia on the function of isolated rat hearts perfused with esmolol-containing Krebs solution were compared with those using high-potassium (25 mmol/L) Krebs solution. Group A subjects (n = 9) received the ischemic injury after being perfused (and arrested) for 20 minutes with either esmolol or potassium (KCl, 25 mmol/L). Group B subjects (n = 10) received the same ischemic insult before being perfused with either esmolol or potassium. Esmolol-treated hearts showed better recovery than those receiving potassium, in terms of +/-dP/dt (p Keywords: -adrenergic receptor; Normothermic cardioplegia; blocker.; esmolol; hyperkalemia Document Type: Research Article DOI: http://dx.doi.org/10.1016/S0003-4975(96)01114-9 Affiliations: Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Canada Publication date: March 1, 1997 $(document).ready(function() { var shortdescription = $(".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } $(".descriptionitem").prepend(shortdescription); $(".shortdescription a").click(function() { $(".shortdescription").hide(); $(".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher In this Subject: Surgery By this author: Ede, M. ; Ye, J. ; Gregorash, L. ; Summers, R. ; Pargaonkar, S. ; LeHouerou, D. ; Lessana, A. ; Salerno, T.A. ; deslauriers, R. GA_googleFillSlot("Horizontal_banner_bottom");
    The Annals of Thoracic Surgery 01/1997; 63(3). · 3.45 Impact Factor
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    ABSTRACT: ANRE/BIOS/INFO; ; ;