Browsing by Author "Alvarez, M"
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- ItemAn integrated model for earthquake risk assessment of buildings(ELSEVIER SCI LTD, 2002) Fischer, T; Alvarez, M; Llera Martin, Juan Carlos de la; Riddell, RThis study is devoted to the formulation and construction of an integrated model for earthquake risk assessment of buildings in seismic regions. The model developed has five stages: i) characterization of ground motion, ii) construction of the building model, iii) evaluation of the inelastic building response, iv) structural damage assessment, and v) risk evaluation. Stages iii) and iv) are emphasized in the current presentation, because they include some newer aspects such as the use of story-shear and torque surfaces for inelastic building analysis and fuzzy logic for assessing the earthquake performance of a structure. Examples including a large building inventory and two individual structures are developed to show the potential use of the model. Results show that the model is capable of discriminating different foundation soils, earthquake performance of shear-wall and frame buildings, asymmetries in height and plan, and between conventional and seismically isolated structures. Such features may be useful to engineers working in city planning, emergency and risk management, and the insurance industry. (C) 2002 Elsevier Science Ltd. All rights reserved.
- ItemDetermination of a BRCA1 gene mutation in a family with hereditary breast cancer(SOC MEDICA SANTIAGO, 2004) Gallardo, M; Faundez, P; Cruz, A; Rodriguez, M; Alvarez, M; Carvallo, PBackground: Breast cancer is the main cause of death among fore, the women between 40 and 55 years old, in whom the hereditary cases are common. Therefore molecular diagnosis of germ line initiations involved in breast cancer susceptibilily is relevant. BRCA1 and BRCA2 have been described as the two major genes involved in familial breast/ovarian cancer. We are performing a screening for BRCA 1 and BRCA2 genes, in a group of 50 high risk Chilean families for breast/ovarian cancer. We have detected a mutation, 3936 C > T, that leads to a truncated protein, in two affected women from one of the families in study.
- ItemDown-regulation of endothelial adhesion molecules and leukocyte adhesion by treatment with superoxide dismutase is beneficial in chronic immune experimental colitis(OXFORD UNIV PRESS INC, 2005) Segui, J; Gil, F; Gironella, M; Alvarez, M; Gimeno, M; Coronel, P; Closa, D; Pique, JM; Panes, JModulation of adhesion molecule expression that govern trafficking of leukocytes into the inflamed intestine is envisioned as a new strategy for treatment of inflammatory bowel disease (IBD). This study was designed to determine the impact of reducing oxidative stress on adhesion molecules expression and leukocyte recruitment in experimental chronic colitis. For that purpose, colitic interleukin-10 knockout and wild-type mice were studied. Groups of animals were treated with Cu/Zn superoxide dismutase (SOD1) 13 mg/kg/d or vehicle for either 7 or 14 days. Expression of vascular cell adhesion molecule-1 and mucosal addressin cell adhesion molecule-1 were determined; leukocyte-endothelial cell interactions in colonic venules were studied with intravital microscopy; and changes in colon pathology and biomarkers of colitis severity were determined. Development of colitis was associated with a marked increase in endothelial vascular cell adhesion molecule-1 and mucosal addressin cell adhesion molecule-1 expression, which were significantly reduced by treatment with SOD1 The increase in leukocyte rolling and adhesion in colonic venules of colitic mice were significantly reduced by administration of SOD1 This treatment markedly reduced colonic lipid hydroperoxidation, myeoloperoxidase activity, and plasma levels of serum amyloid A protein and resulted in significant, although modest, reductions in histologic damage score. The therapeutic value of SOD1 when administered prophylactically was assessed in the dextran sulfate sodium model of colitis with similar positive results. These results indicate that SOD1 affords significant amelioration of colonic inflammatory changes in experimental colitis. Down-regulation of adhesion molecule expression, reduction of lipid hydroperoxidation, and recruitment of leukocytes into the inflamed intestine contribute to this beneficial effect.
- ItemIncidence of BRCA1 and BRCA2 mutations in 54 Chilean families with breast/ovarian cancer, genotype-phenotype correlations(2006) Gallardo, M; Silva, A; Rubio, L; Alvarez, C; Torrealba, C; Salinas, M; Tapia, T; Faundez, P; Palma, L; Riccio, M; Paredes, H; Rodriguez, M; Cruz, A; Rousseau, C; King, M; Camus, M; Alvarez, M; Carvallo, POur aim was to analyze the incidence of mutations in BRCA1 and BRCA2 genes in 54 families with breast/ovarian cancer. Families were selected from three Institutions following the standard criteria for hereditary breast/ovarian cancer. PCR amplification of all exons was performed, followed by SSCP, heteroduplex, PTT and sequencing analysis. We identified eight truncation mutations, three in the BRCA1 gene and five in the BRCA2 gene. Three of these mutations have not been reported previously by other groups: 308insA in one family, 3936 C > T in two families, for BRCA1, and 4970insTG in one family for BRCA2. In addition two families having Ashkenazi Jewish ancestors present the well known mutations 185delAG and 6174delT. Interestingly, 5 out of 11 families have mutations recurrent in Spanish families. Among the 54 families selected, seven have breast and ovary cancer cases, and only two presented a mutation in BRCA1 or BRCA2 genes. Other cancers as prostate and stomach are frequent among relatives carrying the mutation. Five cases of very early onset (< 31 years old) breast cancer were detected. The frequencies of BRCA1 (0.074) and BRCA2 (0.13) mutations in our families is low but similar to the incidence found in other populations, like in Spain. Since is widely known that risk factors that modulate the development of breast cancer such as lifestyle risk factors, geographic location, country of origin and socioeconomic status, besides a familial history of breast cancer our findings suggest that the history of colonization and immigrations is very relevant when studying hereditary factors associated to breast cancer.
- ItemIncreased orocecal transit time in patients with nonalcoholic fatty liver disease(2005) Soza, A; Riquelme, A; González, R; Alvarez, M; Pérez-Ayuso, RM; Glasinovic, JC; Arrese, MIntestinal bacterial overgrowth (IBO) has been suggested to play a pathogenic role in patients with nonalcoholic fatty liver disease (NAFLD). Delayed intestinal transit may contribute to IBO development. Ten nondiabetic patients with NAFLD and abnormal liver enzymes were recruited. Ten healthy individuals, matched by sex, age, and body mass index, were used as controls. Orocecal transit time (OCTT) was measured by the lactulose breath test. Anti-endotoxin core antibodies (EndoCAb) were determined. The effect of oral norfloxacin (400 mg BID during 2 weeks) on liver enzymes, lactulose breath test, and EndoCAb was also studied. NAFLD patients had higher basal breathed H, and prolonged OCTT compared to controls (127 +/- 61 vs. 57 +/- 23 min, respectively; P=0.0037). EndoCAb titers were similar in NAFLD patients and controls. Norfloxacin administration had no effect on ALT levels, lactulose breath test, or EndoCAb titers in patients with NAFLD. The present data show evidence of deranged intestinal motility in nondiabetic patients with NAFLD and support the hypothesis that NAFLD could be linked to endotoxin-induced liver damage of intestinal origin.
- ItemSimultaneous multiwavelength observations of dwarf novae .1. SU Ursae Majoris: Minihumps at a minioutburst?(1996) Echevarria, J; Tovmassian, G; Shara, M; Tapia, M; Bohigas, J; Jones, DHP; Gilmozzi, R; Costero, R; Lopez, JA; Roth, M; Alvarez, M; Rodriguez, LF; DeLara, E; Stover, RJ; MartinezRoger, C; Garzon, F; Asatrian, N; Vogt, N; Szkody, P; Zsoldos, E; Mattei, J; Bateson, FMSU Ursae Majoris-the prototype of a subgroup of dwarf novae that display superhumps in superoutbursts has been observed during an international campaign dedicated to the observation of the first day of outburst of dwarf novae during 1986 February. After the start of a brightening was reported, the star was monitored by IUE, ground-based photometry and spectrophotometry, IR-photometry, and radio observations by VLA. However, it did not undergo a normal outburst or a superoutburst.
- ItemUse of methylene blue in patients with refractory septic shock: Impact on hemodynamics and gas exchange(W B SAUNDERS CO, 1998) Andresen, M; Dougnac, A; Diaz, O; Hernandez, G; Castillo, L; Bugedo, G; Alvarez, M; Dagnino, JPurpose: The purpose of this study was to assess the acute effects of methylene blue, an inhibitor of nitric oxide synthesis, on hemodynamics and gas exchange in patients with refractory septic shock in a prospective clinical trial at medical and surgical intensive care units in a tertiary university hospital.
- ItemUsing the national cancer institute anticancer drug screen to assess the effect of mrp expression on drug sensitivity profiles(1998) Alvarez, M; Robey, R; Sandor, V; Nishiyama, K; Matsumoto, Y; Paull, K; Bates, S; Fojo, TThe MRP gene contributes to one form of multidrug resistance. To identify drugs interacting with MRP, we measured MRP mRNA expression by quantitative PCR in 60 cell lines of the National Cancer Institute Anticancer Drug Screen. Expression was detected in all cell lines (highest in lung carcinomas and central nervous system tumors) with a range of 14-fold. A mean graph of MRP mRNA levels was constructed to determine Pearson correlation coefficients (PCCs) with mean graphs of >40,000 compounds using the COMPARE analysis. Only 20 compounds had PCCs of greater than or equal to 0.500. The PCCs for VP-16, doxorubicin, and vincristine were 0.008, 0.13, and 0.257, respectively. Initially, 36 compounds with PCCs of greater than or equal to 0.428 were analyzed using two MRP-overexpressing cell lines; low levels of cross-resistance was demonstrated for 23 compounds (1.3-9.4-fold). Twenty-four compounds also were available for further studies. Using a fluorescence activated cell sorter assay to measure competition of calcein efflux from MRP-overexpressing cells, 10 compounds were found to increase calcein retention by greater than or equal to 2-fold. Ten compounds also were able to reduce ATP-dependent [(3)H]LTC(4) transport into vesicles from MRP-overexpressing cells. These results contrast with previous studies with MDR-1 in which high correlations were found and confirmed for a large number of compounds. Although other assays may be more revealing, in these unselected cell lines, MRP mRNA expression was a poor predictor of drug sensitivity. This raises the possibility that other factors, including conjugating enzymes, glutathione levels, or other transporters, confound the MRP effect.