Browsing by Author "Gonzalez, S"
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- ItemApocrine gland cyst with hemosiderotic dermatofibroma-like stroma - Report of two cases(LIPPINCOTT WILLIAMS & WILKINS, 2005) Gonzalez, STwo cases of an unusual cutaneous lesion characterized by a dermal nodule with apocrine gland cysts surrounded by a hemosiderotic dermatofibroma-like proliferating stroma are reported. The first case was a 52-year-old female who presented with a nodule on the back of several years of evolution and with the clinical diagnosis of lipoma; the second case was a 41-year-old male who presented with a forehead nodule of several years of evolution with a clinical diagnosis of epidermal cyst. Histologically, an ill-delimited non-encapsulated nodule composed of cystic spaces and solid areas was found. The cystic spaces consisted of ductal structures and a bilayered epithelial covering with apocrine differentiation; the surrounding area showed a stroma composed of a mixture of both fibrocytes and macrophages and abundant hemosiderin granules; foci of recent hemorrhages and a more dense fibrous stroma at the periphery with typical storiform areas were also visible. Both cases have shown a benign course without local recurrence in follow up until this report date.
- ItemCircumscribed palmar hypokeratosis: clinical evolution and ultrastructural study after prolonged treatment with topical calcipotriol(BLACKWELL PUBLISHING, 2005) Urbina, F; Misad, C; Gonzalez, SCircumscribed palmar hypokeratosis is a recently described condition that consists of a solitary area of depressed skin affecting the palm (or sole). Its histo pathological features include a thinned horny layer, a slightly diminished granular cell layer, and intraepidermal vacuolated cells. Prolonged treatment with topical calcipotriol resulted in complete recovery of the affected zone in the case reported here. A second biopsy of the lesion taken at around the fourth year of therapy showed a normalization of the granular layer, a reduction in the intraepidermal vacuolated cells, and a somewhat thicker horny layer. An ultrastructural study carried out at the same time showed a reduction in keratin bundles and keratohyalin granules, and an increase in lipid droplets up to the horny layer. These findings and the therapeutic response to topical calcipotriol support the concept that circumscribed palmar hypokeratosis is a focalized abnormal keratinization defect morphologically expressed at the granular and horny layers.
- ItemDiabetogenic transferrin damages podocytes in early human diabetic nephropathy(GEORG THIEME VERLAG KG, 2001) Gonzalez, S; Vargas, LThe exact mechanisms by which growth hormone (GH) damages the kidney inducing diabetic nephropathy has not yet been elucidated. Recently, it has been shown that transferrin has the same diabetogenic effects of GH, being its mediator. Transferrin was studied using immunohistochemistry and immunoelectron microscopy in cases of early diabetic nephropathy, and in controls. Transferrin was only found in diabetic cases in podocytes and Bowman's capsule cells, but also in the tubular cells of both diabetic and non-diabetic controls. Immune-electron microscopy for the presence of transferrin showed positive signals in the cytoplasm of diabetic podocytes, but not in pedicels. This selective deposition was associated with signs of organelle and cytoskeleton damage. On the basis of previous evidence and present glomerular findings, these results suggest an indirect diabetogenic effect on the kidney by GH mediated through transferrin.
- ItemDifferences between nuclear run-off and mRNA levels for multidrug resistance gene expression in the cephalocaudal axis of the mouse Intestine(ELSEVIER SCIENCE BV, 1995) Chianale, J; Vollrath, V; Wielandt, AM; Miranda, S; Gonzalez, R; Fresno, AM; Quintana, C; Gonzalez, S; Andrade, L; Guzman, SP-glycoprotein is a multidrug transporter encoded by the mdr3 gene in the mouse intestinal epithelium. The aims of this study were to characterize the mdr3 gene expression in the cephalocaudal axis of the intestine in adult animals and during perinatal development, and to define the molecular mechanism responsible for the heterogeneous expression of the gene along the cephalocaudal axis. RNA extracted from stomach, duodenum, jejunum, ileum, cecum and colon was hybridized by slot blot and Northern blot using a mdr3 cDNA probe. The regulation of gene expression was investigated examining the rate of transcription by nuclear run-off analysis. Transport studies of rhodamine 123, a substrate of P-glycoprotein, were performed in everted jejunum and ileum. The level of mdr3 mRNA and P-glycoprotein found in ileum was 6-fold higher than the level found in duodenum. The regional pattern of mdr3 gene expression is established in the intestine of 10-day-old animals. Similar mdr3 hybridization signal in nuclear run-off assay was found in nuclei of enterocytes isolated from jejunum and ileum, suggesting that the heterogeneous expression of the mdr3 gene in the cephalocaudal axis of the small bowel may be predominantly regulated at the post-transcriptional level. Transport rate of rhodamine 123 from the serosal to mucosal side in everted ileum was higher than the rate of transport found in jejunum. These results indicate that enterocytes of the ileum may be more actively involved in the P-glycoprotein-mediated transport of xenobiotics into the intestinal lumen.
- ItemEffect of 0.25 ppm Ozone exposure on. pulmonary damage induced by bleomycin(SOCIEDAD BIOLGIA CHILE, 2005) Oyarzun, M; Dussaubat, N; Gonzalez, STo study the effect of ozone in a chronically damaged lung. we used a bleomycin (BLM) induced pulmonary fibrosis model. Both endotracheal instillation of BLM and O-3 exposure both produce lung inflammation and fibrosis. Oxidative stress would be a common mechanism of damage for both BLM and O-3. Our aim was to assess lung injury induced by 5 and 60 days of intermittent exposure to 0.25 ppm O-3 in rats with bleomycin-induced pulmonary fibrosis. Thirty-day-old Sprague Dawley rats were endotracheally instilled with BLM (IU/100 g body weight) and, 30 days later, exposed to 0.25 ppm O-3 (0.25 ppm 4 h per day, 5 days a week). Histopatology controls were instilled with saline and breathing room air. Histopathological evaluation of lungs was done 5 and 60 days after O-3 exposure. BLM-induced lung damage did not change after 60 days of days of O-3 exposure. Five days of O-3 exposure increased the mean score of BLM-induced pulmonary suggesting that a short-term exposure to O-3 in a previously damaged lung might be a risk factor for developing further lung injury.
- ItemEnrichment of canalicular membrane with cholesterol and sphingomyelin prevents bile salt-induced hepatic damage(AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 1999) Amigo, L; Mendoza, H; Zanlungo, S; Miquel, JF; Rigotti, A; Gonzalez, S; Nervi, FThese studies were undertaken to characterize the role of plasma membrane cholesterol in canalicular secretory functions and hepatocyte integrity against intravenous taurocholate administration. Cholesterol and sphingomyelin concentrations and cholesterol/phospholipid ratios were significantly increased in canalicular membranes of diosgenin-fed rats, suggesting a more resistant structure against solubilization by taurocholate. During taurocholate infusion, control rats had significantly decreased bile flow, whereas diosgenin-fed animals maintained bile flow, Maximal cholesterol output increased by 176% in diosgenin-fed rats, suggesting an increased precursor pool of biliary cholesterol in these animals. Maximal phospholipid output only increased by 43% in diosgenin-fed rats, whereas bile salt output remained at control levels. The kinetics of glutamic oxalacetic: transaminase, lactic dehydrogenase, and alkaline phosphatase activities in bile showed a significantly faster release in control than in diosgenin-fed rats, After 30 min of hp travenous taurocholate infusion, necrotic hepatocytes were significantly increased in control animals.jlr Preservation of bile secretory functions and hepatocellular cytoprotection by diosgenin against the intravenous infusion of toxic doses of taurocholate was associated with an increased concentration of cholesterol and sphingomyelin in the canalicular membrane. The increase of biliary cholesterol output induced by diosgenin was correlated to the enhanced concentration of cholesterol in the canalicular membrane.
- ItemFibrates induce mdr2 gene expression and biliary phospholipid secretion in the mouse(PORTLAND PRESS LTD, 1996) Chianale, J; Vollrath, V; Wielandt, AM; Amigo, L; Rigotti, A; Nervi, F; Gonzalez, S; Andrade, L; Pizarro, M; Accatino, LDisruption of the murine mdr2 gene leads to the complete absence of biliary phospholipids. We tested the hypothesis that the increase in biliary phospholipid output induced by fibrates is mediated via induction of the hepatic mdr2 gene and its encoded product, the P-glycoprotein canalicular flippase. Increased levels of mdr2 mRNA were observed in the liver of mice treated with different fibrates: ciprofibrate, 660+/-155% (as compared with control group); clofibrate, 611+/-77 %; bezafibrate, 410+/-47 %; fenofibrate, 310+/-52 %; gemfibrozil, 190+/-25 % (P < 0.05 compared with control group). Induction of expression of the mdr gene family was specific to the mdr2 gene. Two- to three-fold increases in P-glycoprotein immunodetection were evident on the canalicular plasma-membrane domain of clofibrate- and ciprofibrate-treated mice. Biliary phospholipid output increased from 4.2+/-1.2 nmol/min per g of liver in the control group to 8.5+/-0.6, 7.1+/-2.9 and 5.8+/-2.5 in ciprofibrate-, clofibrate- and bezafibrate-treated mice respectively (P < 0.05 compared with control group). Moreover, a significant correlation between biliary phospholipid output and the relative levels of mdr2 mRNA was found (r = 0.86; P < 0.05). In treated animals, bile flow as well as cholesterol and bile acid outputs remained unchanged. Our findings constitute the first evidence that pharmacological modulation of biliary lipid secretion mediated by fibrates can be related to the overexpression of a specific liver gene product, the mdr2 P-glycoprotein, and are consistent with the hypothesis that the mdr2 P-glycoprotein isoform plays a crucial role in the secretion of biliary phospholipid.
- ItemMolecular alterations in primary prostate cancer after androgen ablation therapy(AMER ASSOC CANCER RESEARCH, 2005) Best, CJM; Gillespie, JW; Yi, YJ; Chandramouli, GVR; Perlmutter, MA; Gathright, Y; Erickson, HS; Georgevich, L; Tangrea, MA; Duray, PH; Gonzalez, S; Velasco, A; Linehan, WM; Matusik, RJ; Price, DK; Figg, WD; Emmert Buck, MR; Chuaqui, RFPurpose: After an initial response to androgen ablation, most prostate tumors recur, ultimately progressing to highly aggressive androgen-independent cancer. The molecular mechanisms underlying progression are not well known in part due to the rarity of androgen-independent Samples from primary and-metastatic sites.