Browsing by Author "Guzman, S"

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    A proposal of guidelines for surgical management of obesity
    (SOC MEDICA SANTIAGO, 2005) Carrasco, F; Klaassen, J; Papapietro, K; Reyes, E; Rodriguez, L; Csendes, A; Guzman, S; Hernandez, F; Pizarro, T; Sepulveda, A
    Obesity is a chronic disease with an increasing prevalence in all groups of age, and is associated to increased general mortality and cardiovascular risk. The multidisciplinary non surgical approach must be the treatment of choice for obese subjects. However, the results of such approach among subjects with severe or morbid obesity, are unsatisfactory. In this group of patients, bariatric surgery and specifically gastric bypass achieves good long term results, maintaining a low body mass index, reducing complications and improving quality of life. Considering the widespread practice of bariatric surgery in Chile, the Nutrition Unit of the Ministry of Health formed a task force to propose update guidelines for the surgical treatment of obesity. These guidelines were proposed after a thorough literature review and discussion with groups that practice bariatric surgery using defined protocols. This document provides a summarized version of the guidelines. The first section discusses the background for bariatric surgery and the second part give specific recommendations for patient management and the formation of reference centers for surgical management of obesity.
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    Differences 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, S
    P-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.
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    Gut mucosal atrophy after a short enteral pasting period in critically ill patients
    (1999) Hernandez, G; Velasco, N; Wainstein, C; Castillo, L; Bugedo, G; Maiz, A; Lopez, F; Guzman, S; Vargas, C
    Purpose: The purpose of this study was to evaluate the presence of gut mucosal atrophy and changes in mucosal permeability in critically ill patients after a short fasting period.
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    Influence of polymeric enteral nutrition supplemented with different doses of glutamine on gut permeability in critically ill patients
    (2001) Velasco, N; Hernandez, G; Wainstein, C; Castillo, L; Maiz, A; Lopez, F; Guzman, S; Bugedo, G; Acosta, AM; Bruhn, A
    OBJECTIVES: To evaluate the effect of glutamine-supplemented polymeric enteral formulas on the recovery of gut-permeability abnormalities in critically ill patients.
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    Neuropeptide Y Y-1 receptors are involved in the vasoconstriction caused by human sympathetic nerve stimulation
    (1997) Racchi, H; Schliem, AJ; Donoso, MV; Rahmer, A; Zuniga, A; Guzman, S; Rudolf, K; HuidobroToro, JP
    Neuropeptide Y, a novel neurotransmitter, interacts with selective membrane receptors to cause vasoconstriction. Frequency- and concentration-dependent isometric contractions were observed in human inferior mesenteric artery and vein mounted rings that were stimulated with either electrical pulses (70 V, 0.5 ms, 2.5-20 Hz) or noradrenaline. The antagonism elicited by 100 nM tetrodotoxin and 1 mu M guanethidine confirmed the neuronal and sympathetic origins of the vasomotor response. Incubation with BIBP 3226 ((R)-N-2-(diphrnacetyl)-N-(4-hydroxyphenyl)-methyl-D-arginineamide), a selective neuropeptide Y Y, receptor antagonist, significantly reduced the vasoconstriction. The incomplete antagonist activity of BIBP 3226 tends to support the hypothesis of sympathetic co-transmission involving neuropeptide Y, adenosine 5'-triphosphate and noradrenaline. These findings were confirmed in parallel studies using rat superior mesenteric artery and vein ring preparations. (C) 1997 Elsevier Science B.V.
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    Predictors of nonalcoholic steatohepatitis (NASH) in obese patients undergoing gastric bypass
    (2005) Boza, C; Riquelme, A; Ibañez, L; Duarte, I; Norero, E; Viviani, P; Soza, A; Fernandez, JI; Raddatz, A; Guzman, S; Arrese, M
    Background: Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are conditions gaining increasing recognition in hepatology as a potential cause of cirrhosis and end-stage liver disease. Obesity is one of the main risk factors. The aims of this study were to determine the frequency of NAFLD in obese patients and to identify variables that predict NASH.
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    Results of surgical treatment of gastric cancer
    (1999) Llanos, O; Guzman, S; Pimentel, F; Ibañez, L; Duarte, I
    Background/Aim: The extent of gastric resection and the role of lymphadenectomy in the treatment of gastric cancer are controversial. Methods: This study evaluates the results of radical gastric resection (D2 lymphadenectomy) in 375 patients with a gastric carcinoma operated according to a prospective protocol, Results: Total gastrectomy was performed in 196 and a subtotal gastrectomy in 179 patients, with an operative mortality of 3.5 and 2.8%. The presence of lymph node metastasis was related to the depth of the tumor in the gastric wall. The cumulative 5-year survival was dependent on the depth of tumoral invasion in the gastric wall and also on the presence of lymphatic metastasis. Curative resection had a significantly better 5-year survival (72%) than noncurative resection (26%). Conclusion: Although it is difficult to prove the benefits of extended lymphadenectomy in the surgical treatment of gastric carcinoma, the results of these series seem to support its usefulness. Copyright (C) 1999 S. Karger AG, Basel.