Choosing Optimal STR Markers for Quality Assurance of Distributed Biomaterials in Biobanking

The quality assurance (QA) is of utmost importance in biobanks when archived biomaterials are distributed to biomedical researchers. For sample authentication and cross-contamination detection, the two fundamental elements of QA, STR genotyping is usually utilized. However, the incorporated number of STR markers is highly redundant for biobanking purposes, resulting in time and cost inefficiency. An index to measure the cross-contamination detection capability of an STR marker, the mixture probability (MP), was developed. MP as well as other forensic parameters for STR markers was validated using STR genotyping data on 2328 normal Koreans with the commercial AmpFlSTR kit. For Koreans, 7 STR marker (D2S1338, FGA, D18S51, D8S1179, D13S317, D21S11, vWA) set was sufficient to provide discrimination power of ~10(-10) and cross-contamination detection probability of ~1. Interestingly, similar marker sets were obtained from African Americans, Caucasian Americans, and Hispanic Americans under the same level of discrimination power. Only a small subset of commonly used STR markers is sufficient for QA purposes in biobanks. A procedure for selecting optimal STR markers is outlined using STR genotyping results from normal Korean population.

Central Somatosensory Conduction Time in Head Injured Patient

The central somatosensory conduction time(CCT) was measured by recording the cerebral and spinal evoked potentials following median nerve stimulation in 24 traumatic brain injury patients. The findings of evoked potential study correlated to the functional independence measure(FIM), mini mental status examination(MMSE) and Glasgow outcome scale(GOS). The CCT of head injured patients was prolonged compared to that of the controls. The CCT with stimulation of the affected side was significantly prolonged compared to that with non- affected side. Abnormal CCT was related to the poor functional status measured by FIM and GOS. There`s no significant difference between groups of absent evoked potential and prolonged CCT by FIM score. These results suggest that the CCT correlates with the functional status of head injured patients. Follow up studies are required to evaluate whether the CCT could be a valuable prognostic indicator or not.