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Start Over Author "Jimenez, D" Publisher elsevier b.v.
68 results on '"Jimenez, D"'

32. Physiological Changes to Transient Exposure to Heat Stress Observed in Laying Hens.

Author

Franco-Jimenez, D. J. and Beck, M. M.

Subjects
*HENS, *EGGS, *PHYSIOLOGICAL effects of heat, *HIGH temperatures, *POULTRY
Abstract

Hy-Line W-36, W-98, and Brown hens lay approximately the same number of eggs/hen housed to 80 wk; however, little is known about differences in performance during heat stress (HS). Two experiments were performed. The first experiment evaluated intestinal calcium uptake (CaT), heat shock protein-70 (HSP70) liver expression, and endocrine status in the 3 strains under heat stress in response to 1 h of transient exposure to high temperature before onset of 18 h of HS. The second experiment evaluated the differences between W-36 and W-98 in acid-base status observed at 2 different ambient temperatures. The HSP7O and CaT data were analyzed as a completely randomized design (CRD) using a 3 × 2 factorial with strain as a 1 factor and preexposed and control treatments as the other. Estrogen and progesterone data were analyzed as a CRD using repeated measures in a 3 × 2 × 2 factorial with strain as a the first factor, preexposure and control treatments as the second factor, and phase of blood collection as the third factor. The data of the second experiment were analyzed as a CRD using repeated measures in a 2 × 2 × 2 factorial with strain, temperature, and phase of blood collection as the factors. The method applied in both experiments was based on the mixed model (SAS). The results show a strain effect, with the higher CaT in the W-36. The results indicated that transient exposure to HS did not induce changes in HSP70 liver expression. In the second experiment, the blood gas values did not differ between strains, except for the partial pressure of CO2, in which the values at 22°C are higher for the W-36. At 38°C, there was an increase in blood pH and a reduction in HCO3- in both strains. The results indicate that endocrine, acid-base status, and Ca homeostasis represent important factors to be considered in assessing genetic differences for thermo- tolerance. [ABSTRACT FROM AUTHOR]

Published
2007
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45. Collecting duct epithelial–mesenchymal transition in fetal urinary tract obstruction.

Author

Butt, M. J., Tarantal, A. F., Jimenez, D. F., and Matsell, D. G.

Subjects
*EPITHELIAL cells, *MESENCHYME, *FETAL diseases, *URINARY tract infections, *CHRONIC kidney failure, *INTRAMEDULLARY rods
Abstract

Renal interstitial fibrosis contributes to the progression of most chronic kidney diseases and is an important pathologic feature of urinary tract obstruction. To study the origin of this fibrosis, we used a fetal non-human primate model of unilateral ureteric obstruction focusing on the role of medullary collecting duct (CD) changes. Obstruction at 70 days gestation (full term approximately 165 days) results in cystic dysplasia with significant medullary changes including loss of the epithelial phenotype and gain of a mesenchymal phenotype. These changes were associated with disruption of the epithelial basement membrane and concomitant migration of transitioning cells presumed responsible for the observed peritubular collars of fibrous tissue. There was an abundance of cells that co-expressed the intercalated cell marker carbonic anhydrase II and smooth muscle actin. These cells migrated through the basement membrane and were significantly reduced in obstructed ducts with peritubular collars. Our studies suggest that fetal urinary tract obstruction results in a CD epithelial–mesenchymal transition contributing to the interstitial changes associated with poor prognosis. This seems restricted to the intercalated cells, which contribute to the expansion of the principal cell population and the formation of peritubular collars, but are depleted in progressive injury.Kidney International (2007) 72, 936–944; doi:10.1038/sj.ki.5002457; published online 1 August 2007 [ABSTRACT FROM AUTHOR]

Published
2007
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