Biomedical subjects

Laura Barreales Tolosa

Publications and source records attributed to Laura Barreales Tolosa.

6 recordsLinked to original sources

PubMed2004

[Systematic review about the usefulness and prognostic value of the p53 oncoprotein and proliferation marker Ki-67 for upper urinary tract transitional cell carcinoma].

OBJECTIVES: To perform a systematic review on the expression and prognostic value of the p 53 oncoprotein and Ki 67 proliferation marker in transitional cell carcinoma of the upper urinary tract. METHODS: A systematic review of cohort, prospective and retrospective studies from 1/1/1990 to 11/24/2003 has been undertaken, performing a bibliographic search both manual and electronic in the main databases. 632 works were found using the keywords "ureter, renal and pelvis tumor", and 14 with "ureter, renal and pelvis tumor, and immunohistochemical". RESULTS: 509 patients were studied; they were selected from 7 retrospective studies about the usefulness of p53 and Ki 67 in transitional cell carcinoma of the upper urinary tract published between 1995 and 2002 (three Spanish studies, three Japanese and one North American). Each one analyzes between 37 and 121 cases, with a mean age of 66.8 years (range 63.0-74.7) and a predominance of male sex in 100% of the studies. The pyelocalyceal site was the most frequent in these series. Treatment is another issue taken into consideration in this papers, being nephroureterectomy the most frequently found. The p53 and Ki 67 percentage expression in various studies has been related to clinical and histological factors. Only 5 studies performed a multivariate analysis using Cox regression models. Three of them deal with Ki 67 and two with p53, although one of the p53 studies associates cyclin E determinations. Only two out of three studies about Ki 67 were considered evaluable, because multivariate analysis was not performed in the other one. CONCLUSIONS: 1) There are a few studies and they are very heterogeneous in terms of design, selection criteria, follow-up, and use of prognostic variables. 2) The analyzed studies establish that oncoprotein p53 and proliferation marker Ki 67 are prognostic factors for transitional cell carcinoma of the upper urinary tract, and 3) To perform a meta-analysis was deemed not indicated because of the heterogeneicity of the studies found in our search.

Biomarkers, Tumor↗

PubMedDate not supplied

[Variable measurement in urologic clinical research].

Epidemiology develops measurements that allow to quantify the occurrence of disease within the population. There are three types of measurements: frequency measurements, explained in this article; association measurements, between the occurrence of disease and some characteristics, the effect of which on the disease is what they intend to measure; and measurements of the potential impact that modification or disappearance of some risk factors would have on the occurrence of disease in the population. The first objective of epidemiological studies is the knowledge of the frequency of disease. There are three basic measurements of frequency of a disease. Prevalence measures the proportion of people that has it in a given moment. Cumulative incidence measures the proportion of people that convert from non-sick individual to sick individual during a specified period of time. Incidence rate is a measure of the instantaneous strength of occurrence of the disease.

Biomedical Research↗

PubMedDate not supplied

[Statistics as support tool and not as a decision tool].

The use of statistics in medical articles has risen a lot during the last decades, however it is used in a thoughtless manner in many instances. Today, Statistics is the only tool that allows the medical researcher to obtain results and benefits from those studies the relationships of which can not be interpreted from a determinist perspective, because it is a branch of applied mathematics objective of which is to manage and quantify the uncertainty of the available information, to support decision taking. The objective of this article is to review the basic statistical concepts that every doctor should know to be able to perform and/or detect quality research, as well as to underline the most frequent errors committed when interpreting statistical results. We review the general concepts about data synthesis and differentiation of the different types of measurements, hypothesis testing and errors that can be committed doing it, the real meaning of the "p" value, differentiation between statistically significant and clinically relevant results, the importance of confidence intervals as a measure of significance and clinical relevance, the confusion generated between two concepts that are different as standard deviation and standard error, and the criteria that govern the selection of the adequate statistical tests to evaluate relationships between variables.

Confidence Intervals↗

PubMedDate not supplied

[Choosing study design in urologic research].

The design of an epidemiological study includes the procedures, methods and techniques by which the researcher tries to obtain valid (avoiding systematic errors or bias) and precise (avoiding random errors) answers to the research question posed. This principal question aimed to be answered is the specific objective of the study, which guides the election of an adequate type of design. The objective of this article is to describe the classification criteria (finality, temporal sequence, directionality, and control of the assignation of different study factors) of the different types of epidemiological studies (experimental, almost-experimental, and observational) and the main advantages, disadvantages, utilities and objectives of each investigation design.

Biomedical Research↗

PubMedDate not supplied

[Design and analysis of a study on reliability and validity of diagnostic tests in urological clinical research].

Diagnosis is a process characterized by uncertainty, which the researcher can approach through knowledge based on the theory of probability, and, as such, it is part of the general decision-making process. To use a test is a process that helps to confirm or refuse the initial probability of the patient to be sick. In this article, we analyze the essential characteristics of diagnostic tests and the principles of effective evaluation of the studies about these tests. We explain in detail what reliability of an instrument is, the types of reliability that there are, and how to analyze them. So that, we introduce concepts such as Pearson's correlation coefficient, intra-class correlation coefficient, and Cohen's Kappa coefficient. Another topic described in this article is measurement of validity, defining the types of validity to be considered on an instrument. Finally, we treat the general principles that rule the design and execution of a study for the evaluation of diagnostic tests, the structure followed by these studies, and mainly the analysis, intention of which is to evaluate to what extent that diagnostic test differentiates between subjects with and without the disease studied. We explore the concepts of sensitivity, specificity, predictive values, and probability ratios, and ROC curves are explained.

Biomedical Research↗

PubMedDate not supplied

[Writing an original research article].

Publication of a scientific work is the final and obligatory stage of any research. Among the various existing types of medical publications, the research original article is the prototype of scientific article. Its finality is to communicate the investigation undertaken to the reader in a coherent, clear and precise manner. With that purpose, the discoveries found by the authors as an answer to a hypothesis are presented and discussed. To send the original article to a biomedical journal, the manuscript should present some adequate formal characteristics, in addition to contain scientifically valid information. That can be achieved by complying with the rules past by the International Committee of Biomedical Journal Editors which have been adopted by a great number of scientific journals as publication requisites. The objective of this article is to describe the structure of the various parts (first page, abstract, introduction, material and methods, results, discussion, and bibliographic references) that constitute the format of the research original article, exposing the main adverse to be avoided during its preparation.

Biomedical Research↗