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Biomedical subjects

M C K Yang

Publications and source records attributed to M C K Yang.

2 recordsLinked to original sources

Accuracy of probing attachment levels using a CEJ probe versus traditional probes.

BACKGROUND: Current interest in the assessment of probing attachment level measurements has been stimulated by recent introduction of novel periodontal probes as well as by the reclassification of periodontal diseases. Clinical attachment level (CAL) is currently the "gold standard" for diagnosing and monitoring periodontal diseases. AIM: To evaluate the performance of the newly introduced cementoenamel junction (CEJ) Probe in detecting CAL using the CEJ as a fixed reference point, and to compare the CEJ Probe with the Florida Disk Probe and a standard Manual Probe (North Carolina Probe). MATERIALS AND METHODS: Three examiners probed 12 periodontal patients to determine intra- and inter-consistency of both the probes and the examiners, over a 4-week time interval. Subjects ranged in age from 22 to 74 years. The experimental design was structured to balance the intra- and inter-examiner consistency at the same site during the two visits. RESULTS: Using the PROC MIXED of SAS, a strong interaction (p<0.001) between the examiner and probes was found. The consistency of probing (repeatability of measurements) depended upon the type of periodontal probe used as well as the skill (experience) of the examiner. Overall, the CEJ Probe displayed a more consistent performance. The CEJ Probe demonstrated greater intra-examiner consistency than the Disk Probe for two examiners (p<0.01). The CEJ Probe also showed increased inter-examiner consistency (p<0.01). CONCLUSIONS: The CEJ Probe has the potential to offer the dental team an efficient, accurate mechanism to chart and monitor attachment level measurements over time. Additional studies, using large numbers of examiners, are needed to assess more clearly the performance of each individual probe.

Adult↗

Microarray experimental design: power and sample size considerations.

Gene expression analysis using high-throughput microarray technology has become a powerful approach to study systems biology. The exponential growth in microarray experiments has spawned a number of investigations into the reliability and reproducibility of this type of data. However, the sample size requirements necessary to obtain statistically significant results has not had as much attention. We report here statistical methods for the determination of the sufficient number of subjects necessary to minimize the false discovery rate while maintaining high power to detect differentially expressed genes. Two experimental designs were considered: 1) a comparison between two groups at a single time point, and 2) a comparison of two experimental groups with sequential time points. Computer programs are available for the methods discussed in this paper and are adaptable to more complicated situations.

Oligonucleotide Array Sequence Analysis↗