Browsing by Author "Velasco, Alfredo"

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    Association of adrenal medullar and cortical nodular hyperplasia - A report of two cases with clinical and morpho-functional considerations
    (HUMANA PRESS INC, 2006) Valdes, Gloria; Roessler, Eric; Salazar, Ivan; Rosenberg, Helmar; Fardella, Carlos; Martinez, Pedro; Velasco, Alfredo; Velasco, Soledad; Orellana, Pilar
    Arterial hypertension of adrenal etiology is mainly attributed to primary hyperaldosteronism. However, subtle expressions of hyperadrenergic or glucocorticoid excess can also generate arterial hypertension. The present report describes two hypertensive patients cataloged as resistant essential hypertensives, in whom adrenal masses were found incidentally, who highlight the need to recognize these tenuous clinical or laboratory presentations. Case 1 was a 50-yr-old female with hyperadrenergic hypertension associated to a left adrenal node, normal cortisol and aldosterone:renin ratio, marginally increased urinary normetanephrine, and a positive I-131 MIBG radioisotope scan. Adrenalectomy normalized blood pressure and urinary metanephrines. Pathology showed a hyperplastic adrenal medulla associated to a multinodular cortical hyperplasia. Case 2 was a 62-yr-old female with progressive hypertension, a slight Cushing phenotype, non-suppressible hypercortisolism, normal urinary metanephrines, and bilateral adrenal nodes. Bilateral adrenalectomy and subsequent replacement normalized blood pressure and phenotypic stigmata. Pathology demonstrated bilateral cortical multinodular hyperplasia and medullary hyperplasia. The clinical study in both patients was negative for MEN. The apparently rare association of cortical and medullary lesions presented by both patients is probably overlooked in routine pathology exams, but should be meticulously searched since the crosstalk between the adrenal cortex and medulla may prompt dual abnormalities.
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    Comparison of snap freezing versus ethanol fixation for gene expression profiling of tissue specimens
    (2004) Perlmutter, M. A.; Best, C. J.; Gillespie, John W.; Gathright, Y.; González Bombardiere, Sergio; Velasco, Alfredo; Linehan, W. M.; Emmert Buck, Michael R.; Chuaqui F., Rodrigo
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    Mismatch repair expression in testicular cancer predicts recurrence and survival
    (WILEY-LISS, 2008) Velasco, Alfredo; Corvalan, Alejandro; Wistuba, Ignacio I.; Riquelme, Erick; Chuaqui, Rodrigo; Majerson, Alejandro; Leach, Fredrick S.
    We investigated mismatch repair (MMR) gene expression in testicular cancer as a molecular marker for clinical outcome (recurrence, response to chemotherapy and death) using protein expression and specific genetic alterations associated with the presence or absence of MMR activity. One hundred sixty-two cases of paraffin-embedded testis cancer specimens were subjected to immunohistochemical analysis using monoclonal antibody for MLH1 and MSH2 MMR proteins and genetic analysis using specific polymorphic markers. The degree of MMR immunoreactivity and genetic instability in the form of loss of heterozygosity (LOH) and/or microsatellite instability (MSI) were determined by comparing matched normal and tumor tissue. The degree of immunohistochemical staining for MMR expression was associated with a shorter time to tumor recurrence, resistance to chemotherapy and death. Furthermore, clinical relapse and cancer specific death was also associated with tumors exhibiting a high degree of MSI, p = 0.01 and 0.04, respectively. In contrast, LOH was not associated with recurrence, resistance to chemotherapy or death. Therefore, MMR expression defines testis cancers with distinct molecular properties and clinical behavior, such that tumors with decreased MMR immunostaining and/or increased frequency of MSI have a shorter time to recurrence and death despite chemotherapy. (c) 2007 Wiley-Liss, Inc.