Applications of isoelectric focusing in forensic serology

The typing of certain polymorphic proteins present in human body fluids is an important aspect of the analysis of serological evidence. This is particularly true when dealing with evidence related to violent criminal activity such as homocide, assault, or rape. Until recently, the routine analysis of the genetic polymorphisms of interest relied upon conventional electrophoretic techniques such as horizontal starch or agarose slab gel or both, cellulose acetate, and vertical polyacrylamide gradient gel methods. These techniques adequately separate a limited number of common variants. In some cases, these methods are still those of choice. However, as a result of the nature of the conventional approach, problems with time required for analysis, resolution, diffusion of bands, sensitivity of protein detection, and cost are often encountered. Isoelectric focusing (IEF) offers an effective alternative to conventional electrophoresis for genetic marker typing. This method exploits the isoelectric point of allelic products rather than charge-to-mass ratio in a particular pH environment. The advantages of employing IEF include: reduction of time of analysis, increased resolution of protein bands, the possibility of subtyping existing phenotypes, increased sensitivity of detection, the counteraction of diffusion effects, and reduced cost per sample.     

Analysis of N,N-diethyl-m-toluamide (DEET) in human postmortem specimens

N,N-diethyl-m-toluamide (DEET) levels in postmortem specimens of stomach and contents, blood, liver, and urine are reported following ingestion of the compound. DEET was analyzed by gas chromatography with an OV-101 column and a nitrogen phosphorus detector. The presence of the compound in the four postmortem specimens was confirmed by mass spectrometry.     

Group-specific component: a review of the isoelectric focusing methods and auxiliary methods available for the separation of its phenotypes

This review compares the major isoelectric focusing methods that have been published for the separation of group-specific component (Gc) phenotypes since 1978. The various parameters of gel composition, size, electrical and running conditions and sample application points are listed. More current auxiliary methods are also listed. These relate to the extraction of Gc from bloodstains and its identification after isoelectric focusing. Protocols are then recommended for the forensic analysis of Gc phenotypes.     

Polymorphism of seminal gamma-glutamyl transpeptidase

Electrophoretic analysis of seminal gamma-glutamyl transpeptidase (GGT) activity of 147 unrelated Japanese males revealed three types of band patterns. An anodal single band, a cathodal single band and heterozygous double bands termed 1, 2 and 2-1, respectively, were commonly identified in the samples. The frequencies of the three types were 1 = 0.22, 2 = 0.33 and 2-1 = 0.44. Seminal stains kept for more than 6 months revealed distinguishable band patterns as well as fresh samples.