Esterase D phenotyping of bloodstains and hair roots by low voltage isoelectric focusing

A new isoelectric focusing method is described for phenotyping of esterase D in blood stains and hair roots. It permitted easy and rapid discrimination of six phenotypes determined by ESD*1, ESD*2 and ESD*7. Experiments showed it to be practicable in forensic stain work. In addition, this technique was also usable in phenotyping of ESD 5.     

The esterase D polymorphism as revealed by isoelectric focusing in ultra-thin polyacrylamide gels

The polymorphism of human red cell esterase D (EsD) was studied using isoelectric focusing (pH 4-6) in ultra-thin polyacrylamide gels. Typing was possible without the EsD isozymes attaining true equilibrium focusing conditions. Using this single method, six phenotypes (EsD 1, 2-1, 2, 5-1, 5-2 and 5) could be recognized in the White population of south-east England. Family studies showed these to be controlled by three co-dominant alleles and the gene frequencies were calculated to be EsD1 0.8856; EsD2 0.0946 and EsD5 0.0198. For successful and reliable EsD typing by this method, the electrophoretic system must be carefully optimized with respect to the duration of electrophoresis and the temperature attained in the gel during the electrophoretic run.     

Studies on the use of isoelectric focusing as a method of phenotyping erythrocyte acid phosphatase

The technique of isoelectric focusing (IEF) in ultra-thin polyacrylamide gels as a method of phenotyping erythrocyte acid phosphatase (EAP) has been applied to a large number of red cell lysates and dried bloodstains. This paper presents the results of this study and discusses some features of the IEF patterns and problems with their interpretation. The IEF patterns of several rare EAP phenotypes are also described. These studies have confirmed that IEF is more sensitive than starch gel electrophoresis as a method of phenotyping EAP in dried bloodstains.     

The use of ultrathin-layer agarose gels for phenotyping erythrocyte acid phosphatase by isoelectric focusing

A method is described for the use of ultrathin-layer agarose gels in phenotyping erythrocyte acid phosphatase (EAP) by isoelectric focusing (IEF). The results obtained using ultrathin-layer agarose gels are shown to be equally reliable and reproducible in comparison to established ultrathin-layer polyacrylamide gels. IEF of EAP on 0.168-mm agarose gels took place in 90 min using the LKB Multiphor system. The technique described allows for both time and cost efficient phenotyping of EAP.     

Population data on the forensic genetic markers: phosphoglucomutase-1, esterase D, erythrocyte acid phosphatase and glyoxylase I

Blood specimens from white and black sample populations from Baltimore, Maryland, were analyzed for the four most forensically important, polymorphic red cell enzyme systems-phosphoglucomutase-1, esterase D, erythrocyte acid phosphatase and glyoxalase I. The distributions of the phenotypes for each marker in each racial group were in Hardy-Weinberg equilibrium. The population data were similar to previously reported data for Whites and Blacks from different geographical locations within the United States.     

Evaluation of a nonequilibrium isoelectric focusing (IEF) method for the simultaneous typing of esterase D (EsD), red cell acid phosphatase (AcP1), phosphoglucomutase (PGM1), adenylate kinase (AK), and adenosine deaminase (ADA)

A nonequilibrium isoelectric focusing method incorporating the chemical spacers MOPS and HEPES was developed and subsequently evaluated for its ability to reliably discriminate common and rare phenotypes in the esterase D (EsD), red cell acid phosphatase (AcP1), phosphoglucomutase (PGM1), adenylate kinase (AK), and adenosine deaminase (ADA) isoenzyme systems. The validation procedures used were blind testing, comparison of results to conventional methods, and evaluation of known rare variant phenotypes. This method proved to be a quick and reliable method for typing all five isoenzyme systems, while providing an excellent probability of discrimination (PD = 0.96).     

The PGM1 polymorphism as revealed by ultrathin-layer isoelectric focusing in the population of Padua

The occurrence of PGM₁ phenotypes in 589 samples from the population of Padua was investigated by ultrathin-layer isoelectric focusing. All ten phenotypes were observed. Frequencies of the PGM₁ alleles (1+ = 0.6180; 1? = 0.1163; 2+ = 0.2122; 2? = 0.0535) have been compared to those found in other populations.     

The polymorphism of transferrin by ultrathin-layer isoelectric focusing. Tf phenotypes and TfC subtypes in the population of Padua

The distribution of Tf phenotypes in the population of Padua was investigated by ultrathin-layer isoelectric focusing. In our sample (n = 618) nine phenotypes, Tf C₁, C₂, C₃, C_3?1, C_2?1, C_3?2, C₁B, C₂B and C₁D, were observed and the following frequencies calculated: TfC₁ = 0.77837; TfC₂ = 0.1804; TfC₃ = 0.03641; TfB = 0.0040; TfD = 0.0008. These gene frequencies have been compared to those found in other populations. Analysis of 101 mother-child pairs was in agreement with an autosomal codominant mode of inheritance.     

Determination of phosphoglucomutase (PGM1), acid phosphatase (ACP), and esterase D (ESD) in human bloodstains by hybrid isoelectric focusing (HIEF)

PGM1, ESD, and ACP were determined in bloodstain extracts by isoelectric focusing (IEF) with carrier ampholytes (CA) and HIEF. HIEF yields superior results in PGM typing from bloodstain extracts, whereas for ESD and ACP typing isoelectric focusing with carrier ampholytes seems to be the method of choice.     

Studies and observations on the use of isoelectric focusing in ultra-thin polyacrylamide gels as a method of typing human red cell phosphoglucomutase

The technique of isoelectric focusing in ultra-thin polyacrylamide gels as a method of typing human red cell phosphoglucomutase (PGM1) has been studied. Typing was possible without the samples attaining true equilibrium focusing conditions. The isozyme patterns so obtained were clearly defined and free from distortion. The importance of assessing relative band intensities when interpreting the isozyme patterns is discussed. Our experience of using the technique to analyse casework material is described.     

Comparison of enzyme assay and radioimmunoassay for the measurement of human acid phosphatase in cases of sexual assault

We investigated whether a radioimmunoassay for prostatic acid phosphatase might be used as a more specific test for the identification of semen in samples from cases of sexual assault than the measurement of total acid phosphatase enzyme activity. The results of the measurement of acid phosphatase by enzyme assay in semen and vaginal swab extracts were compared with the results of the radioimmunoassay. It was found that the radioimmunoassay is a sensitive and more specific method than the enzymic determination of acid phosphatase. Incidentally we have found that a low concentration of an immunological cross reacting acid phosphatase is present in semen free vaginal swab extracts.     

The use of enzymatic hydrolysis for isolation of barbituric acid derivatives from blood (as exemplified by phenobarbital and barbamyl)

Modern isolation techniques by direct extraction with organic solvents or after protein precipitation by various sedimenting or salting-out agents are characterized by low efficiency and do not permit to liberate derivatives of barbituric acid from their complexes with blood proteins. The use of enzymatic hydrolysis makes it possible to break bonds between barbiturates and protein and thereby improve the efficiency of isolation. We performed enzymatic hydrolysis of the model phenobarbital-blood and barbamyl-blood complexes with the use of trypsin, pepsin, chymotrypsin, and papain. The degree of phenobarbital extraction with trypsin and barbamyl was estimated at 62.1 +/- 1.2% and 75.1 +/- 1.6% respectively; in other words, it was 32.7 +/- 1.0% and 51.1 +/- 1.0% higher than that achieved by traditional methods. Certain validation characteristics of the new method are presented.     

The 2D:4D Ratio as a Predictor of the Risk of Recidivism after Court‐mandated Intervention Program for Intimate Partner Violence Perpetrators

Differences in aggressive behavior could be partially explained by differential prenatal exposure to testosterone (T). A peripheral marker of prenatal T exposure is the 2D:4D ratio, which has shown a negative correlation with self‐reported aggression in violent men. This study tested the direct association of the 2D:4D ratio with anger expression and the risk of recidivism in intimate partner violence (IPV) perpetrators after psychotherapeutic intervention program. The sample consisted of IPV perpetrators, whose 2D:4D ratio was measured before the intervention. Moreover, after the intervention, anger expression and risk of recidivism in IPV were assessed. Smaller 2D:4D ratio, especially of the right hand, was related to higher anger expression and risk of recidivism in IPV perpetrators. The contribution of this prenatal marker together with other psychobiological variables could play a key role in the propensity to react aggressively when coping with environmental demands.     

The Persistence of Sperm and the Development of Time Since Intercourse (TSI) Guidelines in Sexual Assault Cases at Forensic Science Ireland,Dublin, Ireland

The persistence of sperm using confirmatory microscopic analysis, the persistence of sperm with tails, time since intercourse (TSI) analysis, and results from the acid phosphatase (AP) reaction from approximately 5581 swabs taken from circa 1450 sexual assault cases are presented. The observed proportions of sperm in the vagina and anus declines significantly after 48 h TSI, and sperm on oral swabs were observed up to 15 h TSI. The AP reaction as a predictor of sperm on intimate swabs is questioned. All AP reaction times gave a low true positive rate; 23% of sperm‐positive swabs gave a negative AP reaction time. We show the AP reaction is an unsafe and an unreliable predictor of sperm on intimate swabs. We propose that TSI not AP informs precase assessment and the evaluative approach for sexual assault cases. To help inform an evaluative approach, TSI guidelines are presented.