A stability study on Gc subtyping in bloodstains: comparison by two different techniques

The limits of determination of Gc subtypes in bloodstains were compared between the immunofixation method and the sulfosalicylic acid precipitation method using isoelectric focusing on polyacrylamide gel. By the immunofixation method Gc subtyping in bloodstains was successfully made at 37 degrees C after 7 weeks, at room temperature after 17 weeks and at 4 degrees C even after 25 weeks storage. By the sulfosalicylic method Gc subtypes were no longer able to be determined a few weeks after stain formation. The superiority of the results obtained by the immunofixation method makes it the recommended method for the Gc subtyping from bloodstains in medicolegal practice.     

A silver staining method for the detection of polymorphic proteins in minute bloodstains after isoelectric focusing

A silver staining method has been developed to study polymorphic proteins in bloodstains after isoelectric focusing. This method is highly sensitive and permits the detection of polymorphic proteins (i.e. alpha 1-antitrypsin, Gc and Tf C subtypes) in bloodstains as small as 0.2 microliter or less. The method is simple and reproducible and can be used after immunofixation. Blood stains can be identified after longer storage periods than is possible by using conventional staining methods.     

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.     

Transferrin subtyping of human bloodstains

A method was described for subtyping transferrin derived from human bloodstains. Bloodstain cuttings were extracted in 0.5% ferrous ammonium sulfate. The extracts were subjected to ultrathin-layer polyacrylamide gel isoelectric focusing. After isoelectric focusing, transferrin was detected by silver staining. This method permitted the successful typing of Tf in 6-month-old blood stains maintained at -20 degrees C and room temperature and 3-month-old bloodstains maintained at 37 degrees C.     

The application of immunoblotting to the phenotyping of group-specific component

A sensitive immunoblotting method for the routine detection of group-specific component (GC) from fresh serum, and from control and casework bloodstains has been developed. GC phenotypes were separated in a thin layer polyacrylamide gel by isoelectric focusing, transferred to nitrocellulose by a rapid capillary blotting procedure, and detected using a double antibody enzyme immunoassay. This method is capable of phenotyping 8 ng of GC extracted from bloodstains, a four-fold increase in sensitivity when compared to immunofixation and silverstaining. A total of 2424 casework bloodstains have been analysed and GC phenotypes identified in 78% of samples. The method is suitable for use in routine laboratories and is more sensitive than other methods for GC phenotyping of casework bloodstains.     

Group specific component subtyping in bloodstains by separator isoelectric focusing in micro-ultrathin polyacrylamide gels followed by immunoblotting

The identification of group specific component (Gc) subtypes derived from blood-stains by separator isoelectric focusing in micro-ultrathin polyacrylamide gels (interelectrode distance: 50 mm) containing 4.5 to 5.4 pharmalytes is described. The separation achieved between Gc 1F and Gc 1S bands is compared favorably with that obtained using separator isoelectric focusing in conventional polyacrylamide gels dimensions (interelectrode distance: 110 to 120 mm). The technique is rapid and economical, and the immunoblotting method described is more sensitive than immunofixation followed by silver staining.     

琼脂糖凝胶电泳法同步检测血液和血斑型特异性成分及转铁蛋白型

作者采用琼脂糖凝胶电泳法和免疫固定技术,同时分析血液和血斑的型特异性成分(Gc)及转铁蛋白(Tf)两种血清型,并调查了北京地区229名汉族健康献血员两种血清型的表型分布及基因频率。     

成都地区汉族Gc亚型的分布及血痕中Gc亚型的检测

作者用免疫固定薄层聚丙烯酰胺凝胶等电聚焦(PAGIF)技术,调查了成都地区无关的125名健康汉族人血清Gc亚型分布。其6种亚型频率(%)分别为:Ge1F=20.8,Ge1S=8.0,Gc1F-1S=18.4,Gc2-1F=30.4,Gc2-1S=16.0和Gc2=6.4。Gc的基因频率为:Cc~(1F)=0.452,Gc~(1S)=0.252和Gc~2=0.296。对保存于室温条件下20周的陈旧血痕进行了Gc亚型定型,获得满意结果。     

Gc subtyping in blood stains by isoelectric focusing in immobilized pH gradients

The applicability of isoelectric focusing in immobilized pH gradients for the Gc-subtyping in the forensic examination of bloodstains was tested. It is shown that due to the excellent separation of the Gc 1S and 1F bands subtyping of bloodstains can be done with high reliability.     

A comparison of the sensitivity of typing group-specific component (Gc) and the phosphoglucomutase (PGM1) locus in control and casework bloodstains by three isoelectric focusing methods

The performance of typing group-specific component (Gc) in bloodstains by two isoelectric focusing methods followed by its detection with silver staining has been compared with an established forensic system of typing phosphoglucomutase (PGM1) locus phenotypes by isoelectric focusing (IEF) in 1 mm gels. For Gc typing ultra-thin isoelectric focusing (UTIEF) gels and immobilized pH gradient (IPG) gels were used. Both laboratory prepared stains and casework stains were examined. The Gc UTIEF method is approximately eight times more sensitive than the existing PGM1 1 mm IEF method for control and casework stains. However, on average, a larger amount of stain was taken from casework stains than control stains for each typing system. A total of 53 casework stains were examined. Comparable success rates of 62% and 64% were obtained for typing Gc on UTIEF gels and PGM1 by 1 mm IEF, respectively. A success rate of 55% was obtained for typing Gc on IPGs. Bloodstains that were over 200 days old were successfully grouped by all three methods.     

The collaborative study on typing group-specific component by eight forensic science laboratories

This report describes a collaborative study on typing group-specific component (GC), conducted between the Central Research and Support Establishment and the forensic science laboratories of England, Wales and Northern Ireland. A population study (n=114) was performed. Fifty blood donors were selected to provide a distribution, slightly biased from normal, in favour of the GC 1F-1F and GC 1F-1S phenotypes. A protocol was devised for preparing large bloodstains. The strongest GC bands were obtained from the edge of a stain after the blood had been treated with K+/EDTA. Each laboratory received a representative portion of the large bloodstains for GC typing. Five of the eight laboratories correctly grouped all the bloodstains. No errors directly attitributable to the system were recorded in over 800 tests, indicating that GC in bloodstains can be typed reliably using the combination of isoelectric focusing in ultrathin narrow pH interval gels followed by immunofixation and silver staining.     

Gc subtypes determined by ultrathin-layer isoelectric focusing. Distribution in the Veneto population (Italy)

The distribution of Gc phenotypes in the population of Veneto was investigated by ultrathin-layer isoelectric focusing. In our sample (n = 732) the six common phenotypes, Gc 1S, 1F, 1S1F, 2, 2-1S, 2-1F and a further phenotype, GC 1S1C3, were observed and the following frequencies calculated: Gc 1S = 0.560792; GC 1F = 0.159153; Gc2 = 0.277323; Gc 1C3 = 0.002732. Our gene frequencies have been compared with those found in other populations.     

An improved method for subtyping Pi in old bloodstains.

Immunofixation procedures were used for detecting alpha-1 antitrypsin protease inhibitor (Pi) phenotypes in bloodstains. Neuraminidase elution of bloodstains, together with isoelectric focusing, immunofixation, and silver staining techniques, makes possible Pi subtyping in old bloodstains. No extra bands appear when the storage time is no longer than three months.     

A method to increase the volume of sample applied to isoelectric focusing gels

Isoelectric focusing of extracts from diluted or aged bloodstains may be more successfully accomplished with larger sample volumes applied to the gel. A technique is described using teflon tubing to apply larger sample volumes (up to 100 μl) to isoelectric focusing (IEF) gels. This method is reproducible and easy to perform.     

Group specific component: isoelectric focusing subtyping and immunoblot detection

A method for the detection of group specific component (Gc) by immunoblotting, following isoelectric focusing (IEF), is described. This isoelectric focusing method resolves the six common phenotypes of Gc using a narrow range pH 4.5 to 5.4 ampholyte. The Gc proteins were passively transferred from the IEF gel to nitrocellulose and detected with goat anti-Gc followed by peroxidase labeled anti-goat immunoglobulin (Ig) antibody. The increased sensitivity of this technique results in the typing of stains older than one year and also those stains with minimal concentrations of the Gc protein. The polyacrylamide gel can also be used for the subtyping of esterase D.     

Double replica electroblotting for the simultaneous phenotyping of C6 and C7, and its application to the examination of bloodstains

A new reliable and reproducible technique for the simultaneous determination of C6 and C7 types is presented, which employs double replica electroblotting after isoelectric focusing. It permitted clear discrimination of both C6 and C7 components, and the patterns were nearly comparable to those demonstrated separately. The population data obtained by this new technique fitted the genetic hypothesis. The present double replica electroblotting method was successfully applied to the combined phenotyping of C6 and C7 from bloodstains which were stored at room temperature for up to 4 weeks. The method is quite suitable for medicolegal examination of bloodstains particularly for the saving in the amount of sample.     

Detectability of group-specific component (Gc) in aged bloodstains

An improved method of group-specific component (Gc) typing was conducted electrophoretically on agarose gel. Individual bloodstains randomly collected from different individual donors over a five-year period at intervals of approximately one month were checked for Gc activity. Group-specific component was typed accurately in dried bloodstains stored at room temperature up to 43 months in age. From 100 different donors, bloodstains ranging in age from 38 to 43 months were tested by the methods described and 73% of the samples were interpretable for Gc.     

Haptoglobin phenotyping by polyacrylamide gel isoelectric focusing and its application to simultaneous typing of serum proteins

A simple isoelectric focusing method for haptoglobin (HP) typing is described. Serum was pretreated first with C. perfringens neuraminidase (CPN) and then with dithiothreitol (DTT). The treated serum was subjected to polyacrylamide gel isoelectric focusing (PAGIF), and the band patterns were detected by immunoblotting. The method could be successfully applied to HP typing of bloodstains as old as 2 months. A slight modification of it enabled HP, complement component C81, and factor I (IF) to be typed simultaneously. The immunoblotting facilitated preservation of HP patterns. Thus, the PAGIF method for HP typing is suitable for routine use in the forensic laboratory.     

Subtyping phosphoglucomutase-1 in semen stains and bloodstains: a report on the method

A method is described for obtaining nondistorted, reproducible phosphoglucomutase-1 subtyping patterns from semen stains and bloodstains. Isoelectric focusing of phosphoglucomutase-1 was accomplished in 80 min in a 0.2-mm-thick polyacrylamide gel with an interelectrode wick distance of 8.0 cm. The gel contained 1.2% (w/v) N-(2-hydroxyethyl) piperazine-N-3-propanesulfonic acid (EPPS) and pH 5 to 7 ampholytes (4% w/v). When maintained at room temperature, laboratory-prepared bloodstains and semen stains could be typed for phosphoglucomutase-1 up to four months and three weeks, respectively. An evaluation of phosphoglucomutase-1 typing by isoelectric focusing and the Group I system was performed on casework samples submitted to the FBI Laboratory. In addition to the increased discriminating probability of phosphoglucomutase-1 when subtyped, isoelectric focusing yielded an increase in positive calls on questioned bloodstains (65.6 versus 36.2%) and dried seminal stains (16.4 versus 13.1%) compared with the Group I system.     

北京地区人群血清型α2HS频率调查与血痕中α2HS的检测

本文采用聚丙烯酰胺凝胶等电聚焦和免疫固定技术,调查北京地区随机人群的α2HS糖蛋白(α2HS)的频率分布。在185名无亲缘关系的健康人中,发现3种常见表型,即α2HS1-1型(99人)、2-1型(74人)、2-2型12人。未发现稀有型。基因频率为:α2HS~1=0.7351,α2HS~2=0.6490。室温中保存6个月的血痕,可检出其α2HS表型。