Diagnosis of acute leukemia in cerebrospinal fluid (CSF-acute leukemia).

Cerebrospinal fluid-acute leukemia (CSF-acute leukemia) is a frequent and serious complication in patients with acute leukemia. One of the major problems of this complication is the diagnosis process itself. CSF cytology is currently considered the gold standard for establishing the diagnosis, a technique which presents various processing limitations, seriously impacting the predictive values. In the last 11 years, studies of CSF flow cytometry analysis done in patients with acute leukemia have demonstrated superiority in comparison with CSF cytology. Although comparative studies between these two techniques have been reported since 2001, no new consensus or formal changes to the gold standard have been established for the CSF acute leukemia diagnosis. The evidence suggests that positive flow cytometry cases, considered as indeterminate cases, will behave like disease in the central nervous system (CNS). Nevertheless, we think there are some variables and considerations that must be first evaluated under research protocols before CNS relapse can be established with only one positive flow cytometry analysis in the setting of indeterminate CSF samples. This paper proposes a diagnostic algorithm and complementary strategies.

[Reproducibility of Her-2/neu overexpression with HERCEP test in invasive ductal breast cancer]. / Reproducibilidad de la sobreexpresión de HER-2/neu con el sistema HERCEP en carcinoma mamario infiltrante.

OBJECTIVE: The aim of this study was to determine the reproducibility of the HERCEP-test (Dako Co. Carpintería Ca) for the assessment of HER-2/neu protein overexpression in archival tissues samples of women with ductal invasive breast carcinoma. MATERIALS AND METHODS: The study population was 40 retrospective and consecutive cases of women with ductal invasive breast carcinoma. The tumors were graded by the Elston and Ellis modified Scarf, Bloom and Richardson score. For immunohistochemical studies, 4 microns thick sections were cut and were immunostained with the HERCEP-test kit. We evaluated the overexpression using the numeric score approved for the FDA of USA, ranging from 0 to 3+ reflecting the intensity and pattern of the immunohistochemical signal present in 10% or more of tumor cells. The slides were reviewed twice independently and blinded by two pathologists. The second assessment was made two months after the first one. The level of inter and intraobserver was quantitated using kappa statistics. RESULTS: The interobserver agreement was 0.98 and the intraobserver agreement was 1.00 and 0.87 respectively. There was no significant differences in the assessment of the different scores of the numeric scale. CONCLUSION: The reproducibility of the numeric score evaluated was excellent.

Helicobacter pylori: sus relaciones y controversias morfológicas / Helicobacter pylori; its relationships and morphologic controversies

Desde 1984 año en que se describió Helicobacter pylori en la mucosa gastrointestinal, se le ha relacionado con múltiples alteraciones morfológicas benignas y malignas. Actualmente se conoce con mayor detalle la distribución de las enfermedades gastroduodenales, sus expresiones morfológicas y las controversias de su relación con HP. El objetivo de este trabajo es revisar algunos de estos aspectos.

Aspectos prácticos sobre el tamaño de la muestra en la investigación clínica / Practical aspects about the size of the sample in clinical research

Antecedentes: El conocimiento el tamaño apropiado de una muestra nos permite estar seguros de si los resultados publicados en diversos informes de la literatura médica tuvieron como base, además de un diseño cuidadoso, una conclusión apropiada, en función de la significancia de la diferencia observada. Para caulcular el tamaño de la muestra debemos tener en cuenta los errores tipo I y II, la varianza, la magnitud del efecto, el nivel de significancia y el poder de la prueba. Para decidir qué tipo de fórmula matemática se utlizará, lo primero que debemos observar es si nuestro estudio es de prevalencia de valores promedio o comparativo. En este artículo se explican algunos conceptos básicos de estadística y se dan cuatro ejemplos sencillos de cálculo de tamaño de muestra.