Papers by ANDREA GONZALEZ
Gastroenterology, 2009
Gastroenterology, Volume 136, Issue 5, Pages A-639-A-640, May 2009, Authors:Fabio D. Nachman; Mar... more Gastroenterology, Volume 136, Issue 5, Pages A-639-A-640, May 2009, Authors:Fabio D. Nachman; Marcela Planzer; Andrea Gonzalez; Laura Corzo; Horacio Vazquez; Cristina Sfoggia; Edgardo Smecuol; Maria Ines Pinto Sanchez; Sonia Niveloni; Emilia Sugai; Hui Jer Hwang ...
Transplantation Proceedings, 2011
OBJECTIVE. The purpose of this study was to prospectively evaluate spiral CT with maximum-intensi... more OBJECTIVE. The purpose of this study was to prospectively evaluate spiral CT with maximum-intensity projection in the diagnosis of hepatic artery thrombosis in patients with liver transplants. SUBJECTS AND METHODS. Thirty liver transplant recipients (19 men, 11 women; mean age, 49 years) underwent Doppler sonography and spiral CT with maximumintensity projection to evaluate both hepatic parenchyma and hepatic vessels. In five cases, these examinations were followed by angiography for suspected hepatic artery thrombosis. RESULTS. Among the 30 patients, results of both Doppler sonography and spiral CT were abnormal in five patients. In all five patients, Doppler sonography revealed an absence of intrahepatic arterial signal (sensitivity, 100%). Spiral CT showed the hepatic artery to be patent from its origin to the anastomosis and then occluded distally in four patients and showed occlusion of the entire hepatic artery in one patient (sensitivity, 100%).
Transplantation, 1999
Background. Accurate and rapid diagnosis of human cytomegalovirus (HCMV) disease in solid organ t... more Background. Accurate and rapid diagnosis of human cytomegalovirus (HCMV) disease in solid organ transplant patients remains a challenge. We evaluated the clinical utility of a quantitative polymerase chain reaction (QPCR) method to diagnose transplant patients with HCMV disease.
The Journal of Molecular Diagnostics, 2001
Concomitantly, we have become more visible to government and regulatory agencies as well. Many of... more Concomitantly, we have become more visible to government and regulatory agencies as well. Many of you have carefully followed the discussions of the Food and Drug Administration (FDA) over the years, and more recently the deliberations of the Secretaries Advisory ...
Seminars in Liver Disease, 2004
Serological and virological testing for the hepatitis C virus (HCV) is essential in the managemen... more Serological and virological testing for the hepatitis C virus (HCV) is essential in the management of patients with chronic HCV infection. Recent advances in molecular virology tests and the development of a new international unit standard have greatly simplified the use and interpretation of these tests. In the absence of treatment, baseline serum HCV RNA does not change over time and does not correlate with the severity of hepatic inflammation or fibrosis on liver biopsy. In contrast, changes in serum HCV RNA level are important predictors of virological response to treatment with pegylated interferon and ribavirin.
Journal of Clinical Microbiology, 2001
We conducted a multicenter clinical evaluation of the second versions of the manual AMPLICOR and ... more We conducted a multicenter clinical evaluation of the second versions of the manual AMPLICOR and the semiautomated COBAS AMPLICOR tests for hepatitis C virus (HCV) RNA (Roche Molecular Systems, Inc., Pleasanton, Calif.). The performance characteristics of these HCV RNA tests for diagnosis of active viral infection were determined by comparison to anti-HCV serological test results, alanine aminotransferase levels, and liver biopsy histology results. A total of 878 patients with clinical or biochemical evidence of liver disease were enrolled at four hepatology clinics. A total of 1,089 specimens (901 serum and 188 plasma) were tested with the AMPLICOR test. Sensitivity compared to serology was 93.1% for serum and 90.6% for plasma. The specificity was 97% for serum and 93.1% for plasma. A total of 1,084 specimens (896 serum and 188 plasma) were tested with the COBAS test. Sensitivities for serum and plasma were the same as with the AMPLICOR test. The specificity was 97.8% for serum and 96.6% for plasma. Of the 69 specimens with false-positive and false-negative AMPLICOR test results relative to those of serology, alternative primer set (APS) reverse transcription (RT)-PCR analysis showed that the AMPLICOR test provided the correct result relative to the specimens containing HCV RNA in 64 (92.7%) specimens. Similarly, 66 of 67 (98.5%) false-positive and false-negative COBAS test results were determined to be correct by APS RT-PCR analysis. There were no substantive differences in clinical performances between study sites, patient groups, specimen types, storage conditions (؊20 to ؊80°C versus 2 to 8°C), or anticoagulants (EDTA versus acid citrate dextrose) for either test. Both tests showed >99% reproducibility within runs, within sites, and overall. We conclude that these tests can reliably detect the presence of HCV RNA, as evidence of active infection, in patients with clinical or biochemical evidence of liver disease.
Genomics, 2003
Loss of heterozygosity (LOH) of chromosomal regions is crucial in tumor progression. In this stud... more Loss of heterozygosity (LOH) of chromosomal regions is crucial in tumor progression. In this study we assessed the potential of the Affymetrix GeneChip HuSNP mapping assay for detecting genome-wide LOH in prostate tumors. We analyzed two human prostate cell lines, P69SV40Tag (P69) and its tumorigenic subline, M12, and 11 prostate cancer cases. The M12 cells showed LOH in chromosomes 3p12.1-p22.1, 11q22.1-q24. 2, 19p13.12, and 19q13.42. All of the prostate cases with informative single-nucleotide polymorphism (SNP) markers showed LOH in 1p31.2, 10q11.21, 12p13.1, 16q23.1-q23.2, 17p13.3, 17q21.31, and 21q21.2. Additionally, a high percentage of cases showed LOH at 6p25.1-p25.3 (75%), 8p22-p23.2, and 10q22.1 (70%). Several tumor suppressor genes (TSGs) have been mapped in these loci. These results demonstrate that the HuSNP mapping assay can serve as an alternative to comparative genomic hybridization for assessing genome-wide LOH and can identify chromosomal regions harboring candidate TSGs implicated in prostate cancer.
Clinical Chemistry, 2004
Background: Development of quality-control criteria to ensure reproducibility of microarray resul... more Background: Development of quality-control criteria to ensure reproducibility of microarray results for potential clinical application is still in its infancy. Methods: In the present studies we developed qualitycontrol criteria and evaluated their effect in microarray data analysis using total RNA from cell lines, frozen tumors, and a commercially available reference RNA. Quality-control criteria such as A 260 /A 280 ratios, percentage of rRNA, and median size of cDNA and cRNA synthesis products were evaluated for robustness in microarray analysis. Furthermore, precision studies using a reference material were performed on the Affymetrix ® HG-U133A high-density oligonucleotide microarrays. The same reference RNA sample was examined in 16 different chips run on 2 different days in the four different modules of the Affymetrix fluidics workstation. Fresh and frozen fragmented cRNAs were also compared. An ANOVA model was fit to identify the main sources of variation. Results: Good-quality samples showed >30% rRNA in the electropherograms and cDNA and cRNA synthesis products with median sizes of 2.0 and 3.0 kb, respectively. Precision studies showed that the main source of variation was the day-to-day variability, minimally affecting hybridization exogenous control genes. Altogether, the results showed that the Affymetrix Genechip ® system is highly reproducible when RNA that meet the quality-control criteria are used (overall P >0.01).
Bone, 2015
Patients with active celiac disease (CD) are more likely to have osteoporosis and increased risk ... more Patients with active celiac disease (CD) are more likely to have osteoporosis and increased risk of fractures. Highresolution peripheral quantitative computed tomography (HR-pQCT) permits three-dimensional exploration of bone microarchitectural characteristics measuring separately cortical and trabecular compartments, and giving a more profound insight into bone disease pathophysiology and fracture. We aimed to determine the volumetric and microarchitectural characteristics of peripheral bones-distal radius and tibia-in an adult premenopausal cohort with active CD assessed at diagnosis. We prospectively enrolled 31 consecutive premenopausal women with newly diagnosed CD (median age 29 years, range: 18-49) and 22 healthy women of similar age (median age 30 years, range 21-41) and body mass index. Compared with controls, peripheral bones of CD patients were significantly lower in terms of total volumetric density mg/cm 3 (mean ± SD: 274.7 ± 51.7 vs. 324.7 ± 45.8, p 0.0006 at the radius; 264.4 ± 48.7 vs. 307 ± 40.7, p 0.002 at the tibia), trabecular density mg/cm 3 (118.6 ± 31.5 vs. 161.9 ± 33.6, p b 0.0001 at the radius; 127.9 ± 28.7 vs. 157.6 ± 15.6, p b 0.0001 at the tibia); bone volume/trabecular volume ratio % (9.9 ± 2.6 vs. 13.5 ± 2.8, p b 0.0001 at the radius; 10.6 ± 2.4 vs. 13.1 ± 1.3, p b 0.0001 at the tibia); number of trabeculae 1/mm (1.69 ± 0.27 vs. 1.89 ± 0.26, p 0.009 at the radius; 1.53 ± 0.32 vs. 1.80 ± 0.26, p 0.002 at the tibia); and trabecular thickness mm (0.058 ± 0.010 vs. 0.071 ± 0.008, p b 0.0001 at the radius with no significant difference at the tibia). Cortical density was significantly lower in both regions (D comp mg/cm 3 860 ± 57.2 vs. 893.9 ± 43, p 0.02; 902.7 ± 48.7 vs. 932.6 ± 32.6, p 0.01 in radius and tibia respectively). Although cortical thickness was lower in CD patients, it failed to show any significant inter-group difference (a-8% decay with p 0.11 in both bones). Patients with symptomatic CD (n = 22) had a greater bone microarchitectural deficit than those with subclinical CD. HR-pQCT was used to successfully identify significant deterioration in the microarchitecture of trabecular and cortical compartments of peripheral bones. Impairment was characterized by lower trabecular number and thickness-which increased trabecular network heterogeneity-and lower cortical density and thickness. In the prospective follow-up of this group of patients we expect to be able to assess whether bone microarchitecture recovers and to what extend after gluten-free diet.
Regional anesthesia and pain medicine
This prospective, randomized, observer-blinded study compared 3 combinations of volume and concen... more This prospective, randomized, observer-blinded study compared 3 combinations of volume and concentration using the same total dose of lidocaine for ultrasound-guided infraclavicular block. Ninety patients were randomized to 1 of 3 combinations of volume and concentration for lidocaine: (1) 52.5 mL of lidocaine 1%, (2) 35 mL of lidocaine 1.5%, and (3) 26.25 mL of lidocaine 2%. In all 3 groups, the total dose administered (525 mg) was the same. In addition, epinephrine 5 fg/mL was used in all subjects. The main outcome variable was onset time. The performance time, number of needle passes, block-related pain scores, success rate (surgical anesthesia), and the incidence of vascular puncture and paresthesia were also recorded. The total anesthesia-related time was defined as the sum of the performance and onset times. The onset times, which were 18.8 ± 5.6 minutes (95% confidence interval [CI], 16.4-21.1 minutes), 20.7 ± 7.0 minutes (95% CI, 18.0-23.5 minutes), and 21.7 ± 6.0 minutes (9...
Journal of the International AIDS Society, 2014
Introduction: The objective of this article is to present the rationale and baseline results for ... more Introduction: The objective of this article is to present the rationale and baseline results for a randomized controlled pilot trial using economic incentives to reduce HIV and sexually transmitted infection (STI) risk among male sex workers (MSWs) in Mexico City. Methods: Participants (n0267) were tested and treated for STIs (chlamydia, gonorrhoea, syphilis and HIV) and viral hepatitis (hepatitis B and C), received HIV and STI prevention education and were randomized into four groups: (1) control, (2) medium conditional incentive ($50/six months), (3) high conditional incentive ($75/six months) and (4) unconditional incentive ($50/six months). In the conditional arms, incentives were contingent upon testing free of new curable STIs (chlamydia, gonorrhoea and syphilis) at follow-up assessments. Results: Participants' mean age was 25 years; 8% were homeless or lived in a shelter, 16% were unemployed and 21% lived in Mexico City less than 5 years. At baseline, 38% were living with HIV, and 32% tested positive for viral hepatitis or at least one STI (other than HIV). Participants had a mean of five male clients in the previous week; 18% reported condomless sex with their last client. For 37%, sex work was their main occupation and was conducted mainly on the streets (51%) or in bars/discotheques (24%) and hotels (24%). The average price for a sex transaction was $25 with a 35% higher payment for condomless sex. Conclusions: The findings suggest that economic incentives are a relevant approach for HIV prevention among MSWs, given the market-based inducements for unprotected sex. This type of targeted intervention seems to be justified and should continue to be explored in the context of combination prevention efforts.
Journal of Clinical Gastroenterology, 2013
Background/Aims: The aim of this exploratory trial was to establish if the probiotic Bifidobacter... more Background/Aims: The aim of this exploratory trial was to establish if the probiotic Bifidobacterium natren life start (NLS) strain strain may affect the clinical course and pathophysiological features of patients with untreated celiac disease (CD). Positive findings would be helpful in directing future studies.
Digestive and Liver Disease, 2010
Background: The usefulness of celiac disease-related serology in monitoring patients on a gluten-... more Background: The usefulness of celiac disease-related serology in monitoring patients on a gluten-free diet has been debated. Aim: To describe serologic changes over time and assess whether serology tests can predict compliance with the gluten-free diet. Methods: Sera obtained at baseline and every 3 months thereafter for 1 year in 82 adult celiac disease patients were assayed for: (1) IgA antigliadin, (2) IgA anti-tissue transglutaminase, (3) IgA endomysial, (4) IgA, and (5) IgG anti-deamidated gliadin peptides, (6) dual detection of IgA and IgG anti-deamidated gliadin peptides, (7) a single assay for IgA and IgG of both anti-deamidated gliadin peptide and anti-tissue transglutaminase, and (8) IgA antiactin antibodies. Results: At 3 months after diagnosis, most antibody assays significant decrease in mean concentrations (p < 0.0001) and the percentage of positive samples (p < 0.0001) with further improvement in subsequent determinations. Strictly adherents had significantly lower concentrations of antibodies (p < 0.01 to p < 0.00001) and smaller proportion of positive samples for IgA endomysial, IgA antiactin antibodies and IgA antigliadin (15.6%, 17.4% and 23.9%, respectively) than partially compliant. At 1 year, IgA endomysial (p < 0.02), IgA antiactin antibodies (p < 0.05) and anti-tissue transglutaminase (p < 0.02) predicted the degree of compliance. Conclusions: Gluten-free diet treatment produced rapid and significant qualitative and quantitative changes in celiac disease-related antibodies which may be useful for monitoring dietary compliance.
Digestive and Liver Disease, 2010
Background: Deterioration of quality of life in the long term has been suggested for celiac disea... more Background: Deterioration of quality of life in the long term has been suggested for celiac disease patients on a gluten-free diet. Aims: To determine long-term quality of life of celiac disease patients and to assess the benefits of glutenfree diet compliance. Patients: We prospectively evaluated 53 newly diagnosed adult celiac disease patients. .002) show significant deterioration compare with 1 year. Most scores remained significantly better than those at diagnosis (p < 0.03 to p < 0.0005). No changes were detected in the Gastrointestinal Symptoms Rating Scale scores. The long-term impairment of quality of life was attributable to the deterioration of most dimensions in patients who were not strictly compliant with the gluten-free diet (p < 0.05 to p < 0.001).
Clinical Gastroenterology and Hepatology, 2011
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Papers by ANDREA GONZALEZ