Forensic analysis of carbohydrate-deficient transferrin (CDT) by HPLC--statistics and extreme CDT values

Background

Carbohydrate-deficient transferrin (CDT) is the most specific serum marker of chronic alcohol abuse so far. There is little knowledge about extreme CDT values of >20% and the more >30% CDT.

Methods

Serum CDT/transferrin ratios from 19,236 serum samples sent to our laboratory for routine CDT analysis were determined by HPLC. About 75% of these serum samples were from traffic or employment medicine investigations. A CDT value frequency histogram was computed and extreme CDT values were clinically validated.

Results

Fourteen thousand four hundred and sixty-one CDT results were normal (≤1.7%) and 4775 increased (1.8–36.9% CDT). Most frequent normal and increased results were 0.9% CDT (n = 1964) and 1.8% CDT (n = 356). CA. 70% of the pathological results were between 1.8% and 5.0% CDT, ca. 88% between 1.8% and 10.0% CDT, and 98% between 1.8% and 20.0%. CDT values >20.0% appeared in 79 cases and results >30.0% in two cases (33.8% and 36.9%). In each case of CDT values >20%, chronic alcohol abuse was the underlying cause as confirmed by anamnestic exploration.

Conclusions

CDT/transferrin ratios are usually <20%. Higher values can appear in rare cases. CDT results >30% can be due to alcohol abuse but should be considered as remarkable single observations. Visualization of the transferrin isoform patterns by HPLC allows the detection of pathological transferrin isoform patterns and of genetic transferrin variants. This is essential for a reliable interpretation of (extreme) CDT values. CDT analysis by immunoassays without physico-chemical confirmatory analysis is no longer acceptable.     

Driving under the influence of alcohol: a sequence analysis approach

Driving under the influence of alcohol is a contributing factor to a number of road traffic accidents. There is, however, a lack of research into the behaviours that lead to drink driving. The current research used a novel approach, behaviour sequence analysis, to investigate the chains of behaviours that lead to drink driving. Statements were taken from individuals (N?=?60) in an interview, reporting a time they had consumed alcohol and driven a vehicle. Statements were coded and the sequences of behavioural pairs were analysed. Results were presented in a state transition diagram, and indicated a variety of behavioural sequences leading to drink driving. A significant chain of events showed that individuals who had attempted to calculate their blood alcohol concentration and then drive a vehicle felt unsafe to drive, after driving. Also, many individuals did not intend to drink and drive; however, influences such as peer pressure and being surrounded by alcohol lead to them being more likely to consume multiple alcoholic drinks, and then drive a vehicle. The current research outlines future research, and implications for polices and laws on behaviours that surround drink driving, as well as providing a new method for research.     

Post-injection hybridization of complementary DNA strands on capillary electrophoresis platforms: A novel solution for dsDNA artifacts

Several laboratories have reported the occurrence of a split or n − 1 peak at the vWA locus in PowerPlex^® 16 and PowerPlex^® ES amplification products separated on 4- and 16-capillary electrophoresis instruments. The root cause of this artifact is post-PCR reannealing of the unlabeled, unincorporated vWA primer to the 3′-end of the tetramethylrhodamine (TMR)-labeled strand of the vWA amplicon. This reannealing occurs in the capillary post-electrokinetic injection. The split peak is eliminated by incorporation into the loading cocktail of a sacrificial hybridization sequence (SHS) oligonucleotide that is complementary to the vWA primer. The SHS preferentially anneals to the primer instead of the TMR-labeled strand of the vWA amplicon. In addition, the n − 10/n − 18 artifact that may be seen at the vWA locus was determined to be due to double-stranded amplicon formed post-electrokinetic injection into the capillary. This was also eliminated by adding in two Complementary Oligo Targets (COT1 and COT2) in addition to the SHS oligonucleotide into the loading cocktail. These three oligonucleotides are complementary to the 33 bases at the 5′-end of the unlabeled vWA amplicon strand and the 60 bases at its 3′-end and therefore compete for hybridization to the TMR-labeled amplicon strand. Incorporation of these three oligonucleotides in the Internal Lane Standard 600 (ILS600) eliminate both the split peak and n − 10/n − 18 artifact in PowerPlex^® 16 and PowerPlex^® ES amplification products without affecting sizing of alleles at the vWA locus or any locus in the PowerPlex^® 16, PowerPlex^® Y, PowerPlex^® ES, AmpFlSTR^® Profiler Plus^® ID, AmpFlSTR^® Cofiler^®, and AmpFlSTR^® SGM Plus^® kits.     

Direct comparison of post-28-cycle PCR purification and modified capillary electrophoresis methods with the 34-cycle “low copy number” (LCN) method for analysis of trace forensic DNA samples

The investigation of samples with low amounts of template DNA remains at the forefront of forensic DNA research and technology as it becomes increasingly important to gain DNA profile information from exceedingly trace levels of DNA. Previous studies have demonstrated that it is possible to obtain short tandem repeat (STR) profiles from <100 pg of template DNA by increasing the number of amplification cycles from 28 to 34, a modification often referred to as “low copy number” or LCN analysis. In this study, we have optimised post-PCR purification techniques applied after only 28 cycles of PCR, as well as using modified capillary electrophoresis injection conditions and have investigated the progressive application of these enhanced approaches. This paper reviews the characteristics of the profiles obtained by these methods compared with those obtained on the same samples after 34-cycle PCR. We observed comparable sensitivity to 34-cycle PCR in terms of the number of profiles with evidence of DNA and the number of allelic peaks per profile and we noted improved peak height and area magnitude with some sample types. Certain parameters reported to be adversely affected in 34-cycle LCN investigations, such as non-donor allele peaks and increased stutter peak ratio, were reduced by this approach. There are a number of advantages for trace samples in progressing from the standard 28-cycle process to the post-PCR processing method as compared to 34-cycle PCR method, including reduced sample consumption, reduced number of PCR amplifications required, and a staged approach to sample processing and profile interpretation.     

单细胞凝胶电泳检测大鼠死后肝细胞核DNA降解

目的应用单细胞凝胶电泳技术(SCGE)检测大鼠死后肝细胞核DNA降解规律,分析与死亡时间的关系,为早期死亡时间的推断提供新的方法。方法在大鼠死后30h内,每隔3h取肝组织样本进行单细胞凝胶电泳,用共聚焦显微镜摄取彗星图像,应用彗星图像分析软件(IM I1.0)进行图像分析,并作统计学分析。结果死后大鼠的肝细胞在电泳图像上出现明显的彗星形拖尾,其尾长(TL)、尾矩(TM)在一定的时间范围内(0~18h)随死亡时间的延长而逐渐增大,二者均与死亡时间(PM I)呈现一定的相关回归关系。结论单细胞凝胶电泳技术可应用于早期死亡时间的推断。     

中国市民社会研究的新进展——《国家与市民社会》(增订版)评介

《国家与市民社会》(增订版)为我们提供了认识和理解市民社会理论的清晰脉络:不但提供了市民社会作为一种需要不断反思的理论模型的面向,同时也提供了市民社会作为一种需要建构的社会实体的面向,或者说,不管是在理论方面还是在经验方面,该书都向读者提供了有关市民社会的令人印象深刻的视野范围,从而为读者较为完整地把握这一理论指明了方向。