• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 5
  • 4
  • 3
  • 1
  • Tagged with
  • 23
  • 23
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Estudi estructural, ultraestructural i histoquímic de les glàndules sexuals accessòries del mascle reproductor porcí (Sus domesticus)

Badia Brea, Maria Elena 22 October 2003 (has links)
El present treball analitza al microscopi òptic i al microscopi electrònic de transmissió les glàndules sexuals accessòries de Sus domesticus (raça Landrace - varietat anglesa) a partir de mascles reproductors porcins adults i sans. Un millor coneixement dels patrons estructural i ultraestructural normals de las glàndules sexuals accessòries permetrà diagnosticar amb facilitat quina ha estat l'estructura o la funció glandular afectada en mascles en els que s'observa una disminució de la qualitat del semen. Per altra banda, els estudis anatomopatològics s'han de complementar amb tècniques histoquímiques que generalment permeten confirmar o excloure un diagnòstic histopatològic previ.Les glàndules sexuals accessòries del mascle reproductor porcí estan molt desenvolupades i inclouen les glàndules vesiculars, la pròstata i les glàndules bulbouretrals. L'epiteli secretor de les glàndules vesiculars està format per cèl·lules columnars, cèl·lules basals i mastòcits. Les cèl·lules columnars es caracteritzen per presentar tres morfologies diferents que es consideren diferents estadis d'un mateix tipus cel·lular: les cèl·lules principals, les cèl·lules clares i les cèl·lules denses. Les cèl·lules principals secreten activament glicoproteïnes N- i O- glicosilades amb residus d'α-L-fucosa, α(16)fucosa, α-D-mannosa, α-D-glucosa, α- i -D-N-acetilgalactosamina, -D-galactosa-(13)-D-N-acetilgalactosamina, α-D-galactosa, galactosa-(14)-N-acetilglucosamina, D-N-acetilglucosamina i àcid neuramínic. Aquestes glicoproteïnes afavoreixen les interaccions entre l'espermatozoide i l'occit i regulen la permeabilitat de la membrana espermàtica. La pròstata està formada per dues porcions glandulars, el cos de la pròstata (BP) y la pròstata disseminada (DP), entre las quals s'observen diferencies estructurals, ultraestructurals, histoquímiques i funcionals. En ambdues porcions, l'epiteli secretor està constituït per cèl·lules columnars principals, denses i cèl·lules basals, i també per cèl·lules cúbiques en el BP i per cèl·lules mucoses en la DP. En ambdues porcions glandulars, se sintetitzen i secreten N- i O- glicoproteïnes neutres i àcides. Aquestes glicoproteïnes s'alliberen mitjançant un mecanisme regulat en el BP y mitjançant un mecanisme regulat i un constitutiu en la DP. Les glucoproteïnes luminals del BP contenen residus de fucosa, mannosa, α- i -D-N-acetilgalactosamina, galactosa-(14)-N-acetilglucosamina, D-N-acetilglucosamina i àcid neuramínic. En la DP les glicoproteïnes presenten, a més, -D-galactosa-(13)-D-N-acetilgalactosamina i α-D-galactosa. Les glicoproteïnes secretades en el BP i en la DP per via regulada, participen en el control de l'estabilitat del plasmalemma dels espermatozoides, eviten la resposta immune uterina i l'aglutinació dels espermatozoides i afavoreixen la seva motilitat progressiva. Les glicoproteïnes secretades per via constitutiva en la DP protegeixen i lubrifiquen la uretra pelviana.L'epiteli secretor de les glàndules bulbouretrals està format per cèl·lules piramidals principals i denses. Les cèl·lules principals sintetitzen i secreten principalment O-glicoproteïnes àcides carboxilades i sulfatades amb residus glicosídics d'N-acetilgalactosamina, -D-galactosa-(13)-D-N-acetilgalactosamina, α-D-galactosa, D-N-acetilglucosamina i àcid neuramínic. Aquests residus proporcionen resistència a la proteolisi a les O-glicoproteïnes secretades, les quals participen en la lubrificació y protecció de l'epiteli, i intervenen en el control de la permeabilitat del plasmalemma dels espermatozoides i en el transport d'ions al seu través. / The present study evaluates by means of light and transmission electron microscopy, the accessory sex glands coming from adult and healthy boars (Sus domesticus Landrace breed - British variety). A deeper knowledge of the normal structural and ultrastructural patterns of the accessory sex glands will allow diagnosing easily the structure or the glandular function affected when a low spermatic quality is observed. On the other hand, anatomopathological studies must to be complemented with histochemical techniques which generally allow confirming or rejecting a previous histopathological diagnostic. The boar accessory sex glands were very developed and formed by the vesicular glands, the prostate and the bulbourethral glands. Columnar cells, basal cells and mast cells composed the secretory epithelium of the vesicular glands. Columnar cells showed three morphologies, which were considered different stages of the same cell typology and named: principal cells, clear cells and dense cells. Principal cells secreted actively N- and O- glycoproteins that exhibited residues of: α-L-fucose, α(16)fucose, α-D-mannose, α-D-glucose, α- and -D-N-acetilgalactosamine, -D-galactose-(13)-D-N-acetilgalactosamine, α-D-galactose, galactose-(14)-N-acetilglucosamine, D-N-acetilglucosamine and neuraminic acid. These glycoproteins improve sperm-oocyte interactions and regulate plasma membrane permeability.The prostate was constituted by two glandular portions, the prostate body (PB) and the disseminate prostate (DP). Both of them showed structural, ultrastructural, histochemical and functional differences. Principal columnar cells, dense columnar cells and basal cells composed the secretory epithelium of these two glandular parts. The PB contained also cubic cells and the DP contained mucous cells. Both glandular portions synthesised and secreted N- and O- neutral and acid glycoproteins. These glycoproteins were thought to be released by a regulated pathway in the BP while in the DP the glycoproteins seemed to follow a regulated and a constitutive pathway. The BP luminal glycoproteins exhibited residues of: fucose, mannose, α- and -D-N-acetilgalactosamine, galactose-(14)-N-acetilglucosamine, D-N-acetilglucosamine and neuraminic acid. The DP glycoproteins also contained -D-galactose-(13)-D-N-acetilgalactosamine and α-D-galactose residues.The BP and the DP glycoproteins secreted by the regulated pathway participate in the control of sperm membrane stability, avoid uterine immune response and sperm agglutination and, improve their progressive motility. The DP glycoproteins secreted by the constitutive pathway protect and lubricate the pelvic urethra.Principal and dense piramidal cells composed the secretory epithelium of the bulbourethral glands. The principal cells mainly synthesised and secreted carboxylated and sulfated acid O-glycoproteins with residues of: N-acetilgalactosamine, -D-galactose-(13)-D-N-acetilgalactosamine, α-D-galactose, D-N-acetilglucosamine and neuraminic acid. These O-linked oligosaccharides make these proteins extremely resistant to proteolysis, provide lubrication and protection to the epithelium, and participate in ion transport throughout the plasma membrane.
22

Paternal Exposure to Ionizing Radiation in Ontario Uranium Miners and Risk of Congenital Anomaly in Offspring: A Record Linkage Case-control Study

Nahm, Sang-Myong 30 August 2012 (has links)
Objective: To determine if paternal preconception exposure to ionizing radiation through uranium mining increases the risk of congenital anomaly (CA) in offspring. Methods: A population-based matched case-control study was conducted. Cases were infants with CAs recorded in the Canadian Congenital Anomalies Surveillance System and born alive in Ontario 1979-86 (ICD-9 codes 740-759); controls were liveborn infants without CAs identified from Ontario birth certificates and individually matched to cases (case-control file {CCF}). Exposed fathers were identified through the linkage of the CCF to the Mining Master File or the National Dose Registry file, which include those who worked in Ontario uranium mines 1952-1986. For men who linked with a case or control child, radon, gamma and total gonadal doses were estimated for three preconception periods: entire, 3-months and 6-months. Odds ratios were estimated using conditional logistic regression. Results: Linkage of 28,991 uranium miners and 40,482 case-control pairs of fathers and offspring in the CCF identified 431 discordant pairs. There was no evidence of increased risk of a child having a CA if the father was ever a uranium miner before conception of the child (OR=0.89, 95% CI=0.74–1.08). Since gamma radiation (especially during the 6-month preconception period) is more biologically relevant to gonads than radon, further analyses were performed on 117 discordant pairs where data on gamma exposures were available. When ever/never miner, exposed to gamma (yes/no), and gamma dose-response variables were all in the model, there was no ever/never miner effect (OR=1.20, 95% CI=0.85–1.69, p-value=0.30), an inverse association for exposure to gamma (OR=0.42, 95% CI=0.25–0.71, p-value=0.001), but most importantly, there was no statistically significant dose-response relationship between gamma dose during the 6-month preconception period and all CAs (OR=1.15 per loge {mSv+0.01}, 95% CI=0.83–1.59, p-value=0.40). Similarly, no dose-response relationship was observed for exposure to gamma radiation in the 3-month preconception period, or for radon or total gonadal radiation in the 3- or 6-month preconception periods. Conclusion: There was no increased risk of a CA among liveborn children of Ontario uranium miners who were exposed to radon, gamma or total radiation during the 3- or 6-month periods before conception.
23

Paternal Exposure to Ionizing Radiation in Ontario Uranium Miners and Risk of Congenital Anomaly in Offspring: A Record Linkage Case-control Study

Nahm, Sang-Myong 30 August 2012 (has links)
Objective: To determine if paternal preconception exposure to ionizing radiation through uranium mining increases the risk of congenital anomaly (CA) in offspring. Methods: A population-based matched case-control study was conducted. Cases were infants with CAs recorded in the Canadian Congenital Anomalies Surveillance System and born alive in Ontario 1979-86 (ICD-9 codes 740-759); controls were liveborn infants without CAs identified from Ontario birth certificates and individually matched to cases (case-control file {CCF}). Exposed fathers were identified through the linkage of the CCF to the Mining Master File or the National Dose Registry file, which include those who worked in Ontario uranium mines 1952-1986. For men who linked with a case or control child, radon, gamma and total gonadal doses were estimated for three preconception periods: entire, 3-months and 6-months. Odds ratios were estimated using conditional logistic regression. Results: Linkage of 28,991 uranium miners and 40,482 case-control pairs of fathers and offspring in the CCF identified 431 discordant pairs. There was no evidence of increased risk of a child having a CA if the father was ever a uranium miner before conception of the child (OR=0.89, 95% CI=0.74–1.08). Since gamma radiation (especially during the 6-month preconception period) is more biologically relevant to gonads than radon, further analyses were performed on 117 discordant pairs where data on gamma exposures were available. When ever/never miner, exposed to gamma (yes/no), and gamma dose-response variables were all in the model, there was no ever/never miner effect (OR=1.20, 95% CI=0.85–1.69, p-value=0.30), an inverse association for exposure to gamma (OR=0.42, 95% CI=0.25–0.71, p-value=0.001), but most importantly, there was no statistically significant dose-response relationship between gamma dose during the 6-month preconception period and all CAs (OR=1.15 per loge {mSv+0.01}, 95% CI=0.83–1.59, p-value=0.40). Similarly, no dose-response relationship was observed for exposure to gamma radiation in the 3-month preconception period, or for radon or total gonadal radiation in the 3- or 6-month preconception periods. Conclusion: There was no increased risk of a CA among liveborn children of Ontario uranium miners who were exposed to radon, gamma or total radiation during the 3- or 6-month periods before conception.

Page generated in 0.0631 seconds