Biomedical subjects

Lynn Wei

Publications and source records attributed to Lynn Wei.

4 recordsLinked to original sources

PubMed2006

LitMiner: integration of library services within a bio-informatics application.

BACKGROUND: This paper examines how the adoption of a subject-specific library service has changed the way in which its users interact with a digital library. The LitMiner text-analysis application was developed to enable biologists to explore gene relationships in the published literature. The application features a suite of interfaces that enable users to search PubMed as well as local databases, to view document abstracts, to filter terms, to select gene name aliases, and to visualize the co-occurrences of genes in the literature. At each of these stages, LitMiner offers the functionality of a digital library. Documents that are accessible online are identified by an icon. Users can also order documents from their institution's library collection from within the application. In so doing, LitMiner aims to integrate digital library services into the research process of its users. METHODS: Case study RESULTS: This integration of digital library services into the research process of biologists results in increased access to the published literature. CONCLUSION: In order to make better use of their collections, digital libraries should customize their services to suit the research needs of their patrons.

Journal Article↗

PubMed2006

An efficient design for a study comparing two drugs, their combination and placebo.

A novel design for a study comparing two drugs (A and B), their combination (AB) and placebo (P) in a stable disease such as chronic asthma is proposed. The primary objectives of the trial are to compare A (a new drug) with placebo and AB with B (an old drug). Other between-treatment comparisons are secondary. The new design consists of the first 2 sequences of a single 4 x 4 Latin square: (A, AB, P, B|P, B, A, AB|AB, A, B, P|B, P, AB, A). The washout period between A and AB and that between P and B are eliminated based on the assumptions that there is no carry-over effect from placebo and that the effect of the combination would be approximately same at steady state either starting the 2 drugs at the same time or adding one later. Equal period effect for Periods 1 and 2, and for Periods 3 and 4 are also assumed for all treatment effects being estimable. Advantages and disadvantages of this design were evaluated and compared with other possible designs. Compared with other possible designs, the new design is more efficient. For example, the new design requires less than (1/4) of the sample size a parallel design would need and it requires (2/3) of the sample size a 4-treatment, 3-period incomplete block design would need for the same power at the same detectable difference. It has a similar efficiency to a 4-treatment, 4-period cross-over design but with a shorter duration. In this design, all between-treatment comparisons are based on direct within-subject information. The new design could also potentially decrease the probability of patient's drop-outs and use of rescue medication due to lack of efficacy during the placebo periods by reducing the number of placebo washout periods. The benefits reaped from the new design seem to outweigh its risks, which include potential bias for the secondary between-treatment comparisons if the additional assumption about period effects are not satisfied and the incapability of directly assessing the onset of action of the combination of 2 drugs.

Anti-Asthmatic Agents↗

PubMed2005

Decision rule based multiplicity adjustment strategy.

To minimize potential controversies in determining the need for multiplicity adjustment for multiple hypotheses, we propose a decision rule based multiplicity adjustment strategy in this paper. Resorting to a predefined decision rule of a clinical trial, one may link the different hypotheses by their logical relationships and divide them into different families. A proper multiplicity adjustment procedure can then be developed by maintaining strong control of Type I error rate within each family. The paper applies the proposed multiplicity adjustment strategy to a published raloxifene clinical trial.

Bone Density Conservation Agents↗

PubMed2003

A comparison of recent methods for the analysis of small-sample cross-over studies.

The standard analysis of variance (ANOVA) method is usually applied to analyse continuous data from cross-over studies. The method, however, has been known to be not robust for general variance-covariance structure. The simple empirical generalized least squares (EGLS) method, proposed in an attempt to improve the precision of the standard ANOVA method for general variance-covariance structure, is usually insufficient for small-sample cross-over trials. In this paper we compare the following commonly used or recent approaches: standard ANOVA; simple EGLS; modified ANOVA method derived from a modified approximate F-distribution; and a modified EGLS method adjusted by the Kenward and Roger procedure in terms of robustness and power while applying to small-sample cross-over studies (say, the sample size is less than 40) over a variety of variance-covariance structures by simulation. We find that the unconditional modified ANOVA method has robust performance for all of the simulated small-sample cross-over studies over the various variance-covariance structures, and has comparable power with the standard ANOVA method whenever they are comparable in type I error rate. The EGLS method (simple or modified) is not reliable when the sample size of a cross-over study is too small, say, less than 24 in the simulation, unless a simple covariance structure is correctly assumed. Given a relatively larger sample size, the modified EGLS method, assuming an unstructured covariance matrix, demonstrates robust performance over the various variance-covariance structures in the simulation and provides more powerful tests than those of the modified (or standard) ANOVA method.

Analysis of Variance↗