Browsing by Author "Schultz, M"
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- ItemAccuracy of invasive and noninvasive tests to diagnose Helicobacter pylori infection after antibiotic treatment(WILLIAMS & WILKINS, 1997) Rollan, A; Giancaspero, R; Arrese, M; Figueroa, C; Vollrath, V; Schultz, M; Duarte, I; Vial, PObjectives: To compare the diagnostic accuracy of the most widely available tests for diagnosis of Helicobacter pylori infection after antibiotic treatment, Methods: A total of 59 H, pylori-positive, duodenal ulcer patients (mean age, 40.7 +/- 11.7 yr; 40 male and 19 female) were treated for 2 wk with either amoxicillin-metronidazole (n = 36) or omeprazole-amoxicillin-tinidazole (n = 23), and after 4 wk, were tested for H, pylori infection by [C-14]urea breath test (UBT), serum IgG antibody level, and multiple antral biopsies for rapid urease testing, histology, Warthin-Starry stain, and polymerase chain reaction to detect H, pylori DNA, Infection status was established by a concordance of test results, Results: H, pylori was eradicated in 47 patients (80%), UBT and rapid urease testing had the best sensitivity and specificity, although not statistically different to Warthin-Starry stain and polymerase chain reaction, Serology and histology had little diagnostic value in this setting due to high proportion of false-positive results, Conclusions: Noninvasive UBT is as accurate in predicting H, pylori status after antibiotic treatment as rapid urease testing and Warthin-Starry stain, Especially for duodenal ulcer patients, UBT could be considered the gold standard to confirm eradication of H, pylori.
- ItemMicrosatellite analysis of synchronous and metachronous tumors - A tool for double primary tumor and metastasis assessment(2003) Tang, MY; Pires, Y; Schultz, M; Duarte, I; Gallegos, M; Wistuba, IIDespite well-established histopathological features and the development of immunostaining of human neoplasms, there are a number of cases in which surgical pathologists cannot assure the origin of synchronous and metachronous tumors. In many cases, the classification of these lesions as either two separate primary tumors or as a single primary tumor with a metastasis has significant implications with respect to patient prognosis and recommendations for therapy. To establish the origin of tumors, we assessed tumor cell clonality using PCR-based microsatellite analysis on microdissected archival tissues for loss of heterozygosity (LOH) and microsatellite instability (NISI) in a series of 19 paired synchronous and metachronous tumors from several organs. As a control group, 15 autopsy cases with an unequivocally recognizable primary tumor and associated metastases were also examined. Based on LOH and MSI findings, and using a panel of 4 to 12 (median 7) microsatellite markers, we were able to establish the clonal pattern of microsatellite changes in 17 out of 19 (89%) biopsy cases and thus determine if they were either double primary tumors (41%) or metastases (59%). Of interest, identical or similar pattern of microsatellite abnormalities were detected in 15 primary tumors and corresponding metastasis from autopsies. Our results indicate that microsatellite analysis for LOH and MSL as an expression of clonality, provides a useful tool to distinguish double primary neoplasms and metastases in synchronous and metachronous tumors.
- ItemMicrosatellite instability and loss of heterozygosity have distinct prognostic value for testicular germ cell tumor recurrence(TAYLOR & FRANCIS INC, 2004) Velasco, A; Riquelme, E; Schultz, M; Wistuba, II; Villarroel, L; Koh, MS; Leach, FSGerm cell tumor (GCT) is the most common genitourinary malignancy of men between the ages of 18 and 35 years. Therapy is ultimately successful in over 90% of patients, however significant morbidity and mortality can be associated with adjuvant treatment and relapse. Molecular markers that predict treatment response and/or poor outcome would have immediate clinical benefit since adjuvant treatment could be selectively reserved for patients at higher risk for relapse and those patients most likely to respond to treatment. In order to identify potential prognostic molecular markers, we evaluated 118 GCT for microsatellite instability (MSI), loss of heterozygosity (LOH) and MSH2 immunostaining to identify tumors associated with relapse and/or poor outcome following initial surgical, medical and/or radiation therapy.
- ItemMismatch repair gene expression and genetic instability in testicular germ cell tumor(2004) Velasco, A; Riquelme, E; Schultz, M; Wistuba, II; Villarroel, L; Pizarro, J; Berlin, A; Ittmann, M; Koh, MS; Leach, FSHuman mismatch repair (MMR) genes encode highly conserved interacting proteins that correct replication errors predisposing to hereditary gastrointestinal and genitourinary malignancies. A subset of sporadic genitourinary tumors also exhibits MMR deficiency and can be identified by measuring the frequency of microsatellite instability (MSI) in cancer cell DNA. We investigated expression of the two most commonly mutated MMR genes, MSH2 and MLH1, in sporadic testicular germ cell tumor (GCT) in order to: (1) determine the expression pattern of MSH2 and MLH1 proteins in normal seminiferous tubules and histologically distinct GCT subtypes, (2) correlate MMR gene expression with genetic instability in GCT and (3) develop a panel of molecular markers that can identify genetically distinct subsets of GCT for prognostic assessment.
- ItemNature and extent of gastric lesions in symptomatic Chilean children with Helicobacter pylori-associated gastritis(WILEY, 2002) Guiraldes, E; Pena, A; Duarte, I; Trivino, X; Schultz, M; Larrain, F; Espinosa, MN; Harris, PChile has one of the highest rates of gastric cancer in the world and most children and adolescents in the country are colonized by Helicobacter pylori. This study assessed the nature and extent of the gastric lesions in 73 consecutive patients aged 5-17 y, referred for upper gastrointestinal endoscopy. Their H. pylori-associated gastric pathology was characterized and these data were compared with their sociodemographic status. Endoscopic assessment was normal in 43 patients while in 30 there was a variety of mucosal lesions. Sixty patients (83%) had histological chronic gastritis of the antrum and in 45 (63%) the lesions also involved the gastric corpus; 90% of patients with chronic gastritis were colonized by H. pylori. Although most of these patients had epithelial erosions and dedifferentiation of the pit epithelium, atrophy and metaplasia were not found. Patients' socioeconomic status was inversely correlated with their rate of colonization by H. pylori (p < 0.005), the frequency of gastric lesions on endoscopy (p < 0.01) and the frequency of involvement of antral and corpus mucosa by chronic gastritis (p < 0.002). This latter feature was positively correlated with age (p < 0.001).
- ItemPravastatin decreases cold ischemia -: But not alloantigen-dependent transplant arteriosclerosis(2003) Domínguez, J; Schultz, MBackground. Alloantigen mismatch and cold ischemia have been shown to induce transplant arteriosclerosis. Pravastatin (PR) decreases arteriosclerosis probably related to an immunosuppressive effect. Statins posses other nonimmune properties that may be beneficial to transplantation. We studied the effect of PR on cold ischemia and alloatntigen-induced transplant arteriosclerosis in syngeneic (SYN) and allogeneic (ALLO) aortic transplantation models.
- ItemProinflammatory cytokine expression in gastric tissue from children with Helicobacter pylori-associated gastritis(LIPPINCOTT WILLIAMS & WILKINS, 2001) Guiraldes, E; Duarte, I; Pena, A; Godoy, A; Espinosa, MN; Bravo, R; Larrain, F; Schultz, M; Harris, PBackground: Helicobacter pylori infection of the gastric mucosa in humans is usually acquired early in life. The chronic inflammation that ensues involves the increased production of inflammatory cytokines. Published data on production of these mediators by gastric mucosa of H. pylori-infected children are few.