The establishment of the presence of sperm in stains by an agar gel electrophoretic method]

Comparative investigation of seminal stains and other secretions from human body and blood as well as objects of plant origin by gel electrophoresis using alkaline values of pH buffer solutions and subsequent enzymography for acid phosphatase made it possible to develop optimal conditions for detection of seminal presence in stains. Good preservation of seminal acid phosphatase in stains during several years is shown.     

The establishment of the presence and group classification of sperm in mixed stains by isoelectric focusing

The article deals with experimental data on design of the method used for detection of sperm, blood and vaginal secretions according to isoelectric points of acid phosphatases, differential diagnosis of ABO group antigens in "mixed" stains as well as detection of phenotype of red cell acid phosphatase by isoelectric focusing method.     

The simultaneous establishment of the presence and classification of human (primate), bird and fish blood by electrophoresis

Electrophoretic method of simultaneous determination of blood presence and its human (primates), bird and fish origin was developed. Method is based on detection of diagnostical characteristics possessing specific electrophoretic mobility and doesn't require use of precipitating sera. Diagnostical feature of human (primates) blood is methaemalbumin detectable in anodic part of electrophoregram and not detectable within the given test conditions in bloodstains of other animals. In bird and fish blood haemoglobin is determined in cathodic part of electrophoregram which differs from mammals blood by its electrophoretic mobility.     

Determination of MN blood group from blood stains by electrophoresis and immunoblotting

The determination of blood groups from blood stains is extremely important in medicolegal practice, but there is the possibility of an error in the determination of MN phenotypes by the absorption-elution test. We investigated a new method applying electrophoresis and immunoblotting. As a consequence of various experiments, the most appropriate pretreatment of blood stains was as follows. Blood stains were immersed in physiological saline for 0.5 to 1 h and centrifuged. The supernatant was discarded. The sediment was dissolved in sample buffer (TRIS-buffered physiological saline containing 2% sodium dodecyl sulfate) and followed by thermodegradation. It was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). After transfer to a nitrocellulose membrane by Western blotting, MN phenotypes could be determined accurately from blood stains by an enzyme immunoassay (EIA) using commercially available polyclonal anti-M and anti-N sera. For blood stains more than 1 month old it was not easy to determine the MN phenotypes.     

The determination of the phenotypes of 3 enzyme systems by the polyacrylamide gel electrophoresis method

Possibility of combined determination of phenotypes of three enzyme system (glyoxylase-1, phosphoglucomutase and 6-phosphogluconate dehydrogenase) in the apparatus with two vertical blocks of polyacrilamide gel (PAAG) was shown. The method is based on the principle of combination of differently composed blocks of PAAG and single universal electrode buffer. High productivity and economy of the method equally with good quality of resulting phoregrams make this method useful for medicolegal practical work.     

变性梯度凝胶电泳及其在法医学中的应用

随着人类基因组计划的实施和迅速发展,人类基因的神秘面纱已逐步揭开,越来越多的疾病或基因多样性均与基因的突变有关。因此,对基因突变的筛选或诊断无论对基础研究还是临床研究均具有重要意义。近年来,一系列新的基因突变检测方法层出不穷的同时,经典的方法也不断得到改进,其中,由Fischer和Lerm an[1,2]创立的变性梯度凝胶电泳(denaturing gra鄄dient gel electrophoresis,D G G E)历经多次改良,已发展成一类极具实用价值的常规突变检测技术,被广泛应用于疾病的诊断或相关基因的筛查、人类基因多态性分析、微生物种群研究等各个领域。一…     

变性梯度凝胶电泳及其在法医学中的应用

随着人类基因组计划的实施和迅速发展，人类基因的神秘面纱已逐步揭开，越来越多的疾病或基因多样性均与基因的突变有关。因此，对基因突变的筛选或诊断无论对基础研究还是临床研究均具有重要意义。近年来，一系列新的基因突变检测方法层出不穷的同时，经典的方法也不断得到改进。     

The use of the obti test for determining the presence and type of blood in stains

A method for simultaneous detection and identification of the blood in stains on material evidence has been tried. Previously these two procedures were carried out in succession and took 2 days, while the new method takes 2-10 min. The method is highly sensitive and specific. Positive results were obtained only with human blood. The method is recommended for practice, specifically, for investigation of complex blood traces (washed and old) on material evidence.     

Analysis of human vaginal secretions by SDS-polyacrylamide gel electrophoresis

Proteins in 68 vaginal secretions from 50 women were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Although there were considerable numbers of intermediate types, the secretions could be classified into the following groups based on the densitometric patterns. A relatively low concentration of 67K protein (albumin) and a high concentration of 52K protein (IgG) were the patterns common to pre- and post-menstrual phases and pregnant stadium. A relatively high concentration of the 67K protein and a moderate concentration of the 52K protein characterized the midcycle. A considerably high concentration of 67K protein compared with the 79K (transferrin), 58K (IgA) and 52K bands was the pattern for menstrual phase and postpartum stage.     

Analysis of postmortem DNA degradation by single-cell gel electrophoresis

One of the most important longstanding problems in the field of forensic medicine is the determination of the time of death upon the discovery of a possible homicide victim. With a majority of homicide victims discovered within the first 48h, it is critically important to be able to determine time of death quickly, and with accuracy and precision. Current methods of determining postmortem interval (PMI) vary, but none can provide better than an 8-h window time estimate. In this paper, the potential application of single-cell gel electrophoresis (SCGE), also known as the comet assay, to evaluate postmortem cell death processes, specifically nuclear DNA fragmentation, is assessed. Upon the death of an organism, internal nucleases contained within the cells should cause chromosomal DNA to degrade into increasingly smaller fragments over time, and if these fragments can be isolated and visualized, the fragmentation should prove to be measurable and quantifiable. An original study providing proof of the concept of postmortem DNA fragmentation between early and late time periods was conducted using human leukocytes. With an established trend seen in the leukocyte results, this study was then expanded using a porcine animal model, over a longer time period, with more frequent time-points evaluated. DNA degradation in all samples was revealed by SCGE and quantified by the use of DNA-specific quantitative stains, as measured by digital camera affixed to a microscope. The comet 'tail-moment' gave a measure of the proportion of fragmented to non-fragmented DNA, while the 'tail-length' provided the relative size of degraded DNA fragments. In both models, an increase in DNA fragmentation was found to correlate with an increased PMI from 0 to 56h postmortem, as evaluated by comet-tail-moment and by comet-tail-length, with tail-length providing the strongest statistical correlation, based upon regression analysis. The postmortem DNA fragmentation observed in this study, reveals a sequential, time-dependent process with the potential for use as a predictor of PMI in homicide cases.     

Detection of cocaine in blood stains]

Cocaine is rapidly degraded in blood samples, and its degradation was found to be highly dynamic in nature. The analysis of blood spots dried on filter paper may provide a method to minimize the break-down of cocaine and to largely preserve the analytical profile of the parent drug and its hydrolysis products at the time of sampling. The short term stability of cocaine in 100 microL blood spots prepared from unpreserved and preserved (sodium fluoride, 0.25%) blood samples was compared to the stability of the particular whole blood specimens stored in tubes at ambient temperature and at -20 degrees C. Due to dehydration, both the chemical and the enzymatic hydrolysis of cocaine and its products could be stopped in dried blood spots. More than 75% of the initial cocaine concentration could be detected in the blood spots, and the analytical profile was ensured for 17 days. Provided its practical suitability, the spot technology should offer a simple approach to detect actual impairment of motorists taken in police custody in the view of section 24a of the German traffic act as well as in cocaine associated criminal cases.     

The simultaneous identification of seminal acid phosphatase and phosphoglucomutase by starch gel electrophoresis

Although elevated acid phosphatase (AP) activity in vaginal fluid is a consistent indicator for semen, differentiation between vaginal AP and seminal AP provides a more meaningful result. Detection of seminal AP in mixtures of vaginal AP, feces, and blood is accomplished by starch gel electrophoresis, employing the substrate thymolphthalein monophosphate as a selective visualization agent. Genetic phosphoglucomutase isoenzymes are simultaneously separated by this method and allow differentiation in some semen/vaginal fluid mixtures.     

Development of a radial gel diffusion technique for the identification of urea in urine stains

A radial gel diffusion method utilizing urease and bromthymol blue has been developed for urine stain identification. Urea, present in urine in relatively high concentrations, can be detected from urine stain extracts. This technique provides both qualitative and quantitative results, and is sensitive enough to detect 0.078 micrograms/microliter of urea.     

Blood typing of blood stains on sweat stains by the iso-agglutinins detection method

When a blood typing is made for mixed stains of sweat and blood, erroneous results may be obtained. The reason is that the blood group substance in the sweat is detected at the same time as that in the blood. In this paper the typing of the blood stain on the sweat stain is carried out by the detection of isoagglutinins which may give additional information to the forensic serologist.