Étude de l'Aplasia cutis congenita (epitheliogenesis imperfecta) chez l'espèce porcine

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Anatomic and molecular characterization of the 1 endocrine pancreas of a teleostean fish: Atlantic wolffish (Anarhichas lupus)

Background: The biologic attributes of the endocrine pancreas and the comparative endocrinology of islet amyloid polypeptide (IAPP) of fish are not well described in the literature. This study describes the endocrine pancreas of one teleostean fish. Ten captive Atlantic wolffish (Anarhichas lupus) from the Montreal Biodome were submitted for necropsy and their pancreata were collected. Results: Grossly, all the fish pancreata examined contained 1-3 nodules of variable diameter (1-8 mm). Microscopically, the nodules were uniform, highly cellular, and composed of polygonal to elongated cells. Immunofluorescence for pancreatic hormones was performed. The nodules were immunoreactive for insulin most prominent centrally, but with IAPP and glucagon only in the periphery of the nodules. Exocrine pancreas was positive for chromogranin A. Not previously recognized in fish, IAPP immunoreactivity occurred in α, glucagon-containing, cells and did not co-localize with insulin in β cells. The islet tissues were devoid of amyloid deposits. IAPP DNA sequencing was performed to compare the sequence among teleost fish and the potency to form amyloid fibrils. In silico analysis of the amino acid sequences 19-34 revealed that it was not amyloidogenic. Conclusions: Amyloidosis of pancreatic islets would not be expected as a spontaneous disease in the Atlantic wolffish. Our study underlines that this teleost fish is a potential candidate for pancreatic xenograft research

Microtubule disrupting N-phenyl-N’-(2-chloroethyl) ureas display anticancer activity on cell adhesion, P-glycoprotein and BCL-2-mediated drug resistance

Objective: Our research program has focused on the development of promising, soft alkylating N-phenyl-N’-(2-chloroethyl)urea (CEU) compounds which acylate the glutamic acid-198 of β-tubulin, near the binding site of colchicum alkaloids. CEUs inhibit the motility of cancerous cells in vitro and, interestingly, exhibit antiangiogenic and anticancer activity in vivo. Mitotic arrest induced by microtubule-interfering agents such as CEUs remains the major mechanism of their anticancer activity, leading to apoptosis. However, we recently demonstrated that microtubule disruption by CEUs and other common antimicrotubule agents greatly alters the integrity and organization of microtubule-associated structures, the focal adhesion contact, thereby initiating anoikis, an apoptosis-like cell death mechanism caused by the loss of cell contact with the extracellular matrix. Methods: To ascertain the activated signaling pathway profile of CEUs, flow cytometry, Western blot, immunohistochemistry and transfection experiments were performed. Wound-healing and chick embryo assays were carried out to evaluate the antiangiogenic potency of CEUs. Results: CEU-induced apoptosis involved early cell cycle arrest in G2/M and increased level of CDK1/cycline B proteins. These signaling events were followed by the specific activation of the intrinsic apoptosis pathway, involving loss of mitochondrial membrane potential (Δψm) and ROS production, cytochrome c release from mitochondria, caspase activation, AIF nuclear translocation, PARP cleavage and nuclear fragmentation. CEUs maintained their efficacy on cells plated on pro-survival extracellular matrices or exhibiting overexpression of P-glycoprotein or the anti-apoptotic protein Bcl-2. Conclusion: Our results suggest that CEUs represent a promising new class of antimicrotubule, antiangiogenic and pro-anoikis agents

Reporte de caso: Estesioneuroblastoma en un equino

Esthesioneuroblastoma or olfactory neuroblastoma is a malignant tumor and is derived from the olfactory neuroepithelium, rare in domestic species and particularly in equines. The present report corresponds to a 13-year-old equine patient who presented chronic respiratory disease with two years of evolution and in which period developed unilateral proptosis. At necropsy, an intracranial mass of soft consistency was found, partially delimited in the aboral region within the left nasal cavity, which extended, partially compromising the bones, presphenoids, ethmoids and membranous structures in the ethmoidal and orbital region, causing the partial protrusion of the eyeball and face compression of the left cerebral hemisphere, secondary lesions in the maxillary tuberosity, pterygopalatine fossa and guttural pouch. The microscopic findings corresponded to a neoplastic process of neuroendocrine origin, whose cells are arranged in supported nests and separated by a fine fibrovascular stroma. The neoplastic process was confirmed by immunohistochemical (IHC) and histochemical (HQ) methods, where the tumor cells were positively marked by antibodies against synaptophysin, S-100 protein antigen, neurospecific enolase (NSE) and chromogranin A. Stained Grimelius argyrophil-argentaphin cells were identified. Based on the macroscopic and microscopic findings and the use of IHQ and HQ, the presence of esthesioneuroblastoma was established.El estesioneuroblastoma o neuroblastoma olfatorio es un tumor de carácter maligno y se deriva del neuroepitelio olfatorio, poco frecuente en especies domésticas y en particular en equinos. El presente reporte corresponde a un paciente equino de 13 años que presentó enfermedad respiratoria crónica con dos años de evolución y en cuyo periodo desarrolló proptosis unilateral. En la necropsia se encontró masa intracraneal de consistencia blanda, parcialmente delimitada en la región aboral dentro de la cavidad nasal izquierda, que se extendió comprometiendo parcialmente los huesos, preesfenoides, etmoides y estructuras membranosas en la región etmoidal y orbital, causando la protrusión parcial del globo ocular y compresión rostro aboral del hemisferio cerebral izquierdo, lesiones secundarias en la tuberosidad maxilar, fosa pterigopalatina y bolsa gutural. Los hallazgos microscópicos correspondieron a un proceso neoplásico de origen neuroendocrino, cuyas células se disponen en nidos soportadas y separadas por fino estroma fibrovascular. El proceso neoplásico se confirmó por métodos inmunohistoquímicos (IHQ) y de histoquímica (HQ), en donde las células tumorales se marcaron positivamente mediante anticuerpos contra sinaptofisina, antígeno de la proteína S-100, enolasa neuroespecifica (NSE) y cromogranina A. Con tinción Grimelius se identificaron células argirófilas-argentafines. Con base a los hallazgos macroscópicos, microscópicos y la utilización de IHQ y HQ se estableció la presencia de estesioneuroblastoma

Inhibition of Islet Amyloid Polypeptide Aggregation and Associated Cytotoxicity by Non-steroidal Anti-Inflammatory Drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) constitute an important pharmacotherapeutic class which, over the past decade, have expanded in application to a panoply of medical conditions. They have been tested for neurodegenerative diseases such as Alzheimer’s to reduce the inflammation and also in the attempt to abrogate amyloid deposition. However, the use of NSAID as aggregation inhibitors has not been extensively studied in pancreatic amyloid deposition. Pancreatic amyloidosis involves the misfolding of islet amyloid polypeptide (IAPP) and contributes to the progression of type 2 diabetes in the human and feline. To ascertain their anti-amyloidogenic activity, several NSAIDs were tested using fluorometric ThT assays, circular dichroism, photo-induced cross-linking assays and cell culture. Celecoxib, diclofenac, indomethacin, meloxicam, niflumic acid, nimesulide, phenylbutazone, piroxicam, sulindac, tenoxicam reduced fibrillization at a molar ratio of 1:10. The circular dichroism spectra of diclofenac, piroxicam and sulindac showed characteristic spectral signatures found in predominantly α-helical structures. The oligomerization of hIAPP was abrogated with diclofenac and sulindac at a molar ratio of 1:5. The cytotoxic effects of pre-incubated hIAPP on cultured INS-1 cells were noticeably reduced in the presence of diclofenac, meloxicam, phenylbutazone, sulindac and tenoxicam at a molar ratio of 1:10. Our results demonstrate that NSAIDs can provide chemistry scaffolds to generate new promissing anti-amyloidogenic agents that can be used alone or as a coadjuvant therapy.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Wildlife sequences of islet amyloid polypeptide (IAPP) identify critical species variants for fibrillization

<div><p></p><p>Amyloid can be detected in the islets of Langerhans in a majority of type 2 diabetic patients. These deposits have been associated with β-cell death, thereby furthering diabetes progression. Islet amyloid polypeptide (IAPP) amyloidogenicity is quite variable among animal species, and studying this variability could further our understanding of the mechanisms involved in the aggregation process. Thus, the general aim of this study was to identify IAPP isoforms in different animal species and characterize their propensity to form fibrillar aggregates. A library of 23 peptides (fragment 8–32) was designed to study the amyloid formation using <i>in silico</i> analysis and <i>in vitro</i> assays. Amyloid formation was impeded when the NFLVH motif found in segment 8–20 was substituted by DFLGR or KFLIR segments. A 29P, 14K and 18R substitution were often present in non-amyloidogenic sequences. Non-amyloidogenic sequences were obtained from <i>Leontopithecus rosalia, Tursiops truncatus</i> and <i>Vicugna pacos</i>. Fragment peptides from 34 species were amyloidogenic. To conclude, this project advances our knowledge on the comparative pathogenesis of amyloidosis in type II diabetes. It is conceivable that the additional information gained may help point towards new therapeutic strategies for diabetes patients.</p></div

Performance of behavioral assays: the Rat Grimace Scale, burrowing activity and a composite behavior score to identify visceral pain in an acute and chronic colitis model

Abstract. Introduction:. The Rat Grimace Scale (RGS), a facial expression scale, quantifies the affective component of pain in rats. The RGS was developed to identify acute and inflammatory pain, and applicability in acute and chronic visceral pain is unknown. The dextran sulfate sodium (DSS) colitis model is commonly used in rats, but pain is rarely assessed, instead, disease progression is monitored with the Disease Activity Index (DAI; assessing fecal blood, stool consistency, and weight loss). Objectives:. The aim of this study was to assess whether the RGS and 2 additional behavioral tools (composite behavior score [CBS] and burrowing) could identify pain in an acute and chronic DSS colitis model. Methods:. Male and female Sprague-Dawley rats were block randomized to (1) acute colitis (4 days DSS in drinking water); (2) chronic colitis (4 days DSS, 7 days water, and 3 days DSS); or (3) control (14 days water). Disease Activity Index, RGS, CBS, and burrowing assessments were performed daily. Results:. Rat Grimace Scale scores increased as DAI scores increased during both acute and chronic phases. Burrowing only decreased during the acute phase. By contrast, CBS scores did not increase significantly during either colitis phase. Conclusions:. These data show that the RGS and burrowing did not decrease in a sustained manner during chronic phase visceral pain, and that variables assessed in the DAI are indicative of pain. This suggests that the RGS can be applied to a wider range of pain types and chronicity than originally suggested. These findings increase the application of the RGS as a pain scale and welfare improvement tool