Information from penile swabs in sexual assault cases

A survey has been made to assess the evidential value of tests carried out on 660 casework penile swabs. Most were from suspects in sexual assaults and were examined to see if the donor had had recent anal, oral or vaginal intercourse. The swabs were tested for one or more of the following: blood, faeces, saliva, vaginal secretions, semen. Blood was seldom found, it was usually weak and insufficient for grouping. Faeces were only identified on a pair of swabs from a dead homosexual showing that proof of buggery by this means is rare. Amylase, suggestive of saliva and oral intercourse, was occasionally detected. Glycogen-rich epithelial cells were sometimes present indicating vaginal intercourse. Semen was frequently found but its presence may not result from a recent sexual act. An ABO group different from the donor was obtained from a fifth of the swabs typed. Grouping in other blood group systems was rarely attempted or successful. Penile swabs provided a means of detecting a victim's ABO blood group on a suspect when it would not have been possible to demonstrate the suspect's group on samples from the victim. They also had value in assaults involving more than one offender. The main limitation of penile swabs was the paucity of material on them and the sampling site affected the interpretation of the results.     

Evaluation of the 190H analogues of prostaglandins E1, E2, F1 alpha and F2 alpha as specific markers for the identification of human semen in body fluid mixtures

The specificity of antisera raised against each of the prostaglandin series 190H E1/E2 and 190H F1 alpha/F2 alpha, produced in males, was evaluated by radioimmunoassay. Further, the ability of these antisera to detect semen specific prostaglandins in mixtures of body fluids was examined. Antisera directed against the 190H E1/E2 series cross-reacted with prostaglandin E1 and marginally with E2. Antisera raised to the 190H F1 alpha/F2 alpha series were, however, highly specific to the semen specific prostaglandins 190H F1 alpha/F2 alpha and 190H E1/E2. It was possible to detect picogramme quantities of contaminating 190H F1 alpha/F2 alpha on vaginal swabs taken up to 72 h after intercourse and on vaginal swabs stored at room temperature for up to 2 years. These prostaglandins were not detected on semen free vaginal swabs, in faecal material, saliva, urine or in a sample of human milk (stain). A limited study of casework material is also described. Detection of the 190H F series, as a group, has considerable potential in the identification of human semen at picogramme levels, eliminating the need for alternative chemical tests and extensive microscopic examination.     

Prostaglandin E in vaginal smears--a possibility for sperm detection in azoospermia]

The identification of seminal traces is exceptionally difficult, if the semen of the assailant is azoospermic. The evident value of prostatic acid phosphatase (PAP) activity must be evaluated in such cases with caution. In a murder investigation of a 13 year old girl a positive PAP reaction was found in vaginal swabs and in her underpants. Spermatozoa could not be found. Using the gas-chromatographic method, described by Douse (1985) the presence of prostaglandin E could be demonstrated in the swabs as well as in the crotch of the underpants. The offender was found to be a man with azoospermia, who admitted intercourse but with the consent of the victim. The E prostaglandins are mainly synthesized in the vesiculae seminal and seen to be specific for semen. Swabs taken from mouth and rectum showed negative reactions for prostaglandins in this case. Prostaglandins could never be detected in vaginal swabs taken at least 7 days after intercourse. Conversely Douse could detect prostaglandins in swabs up to 58 hours after intercourse. Apparently the prostaglandin detection by Douse provides a suitable alternative besides to the quantitative and immunological PAP detection or the immunological detection of the protein p 30.     

Studies on glyoxalase 1 isoenzymes in semen stains: polymorphism in Himachal (India) population

One hundred and ten pairs of blood and semen samples and their stains were studied to type glyoxalase 1 (GLO 1) isoenzymes using agarose-starch medium. A good agreement was observed between the phenotypes expressed in blood and semen samples of the same donor. No GLO 1 activity however could be demonstrated in the vaginal swabs tested. The gene frequencies of GLO 1 polymorphs in Himachal population has been worked out and their stability studies carried out at -12 degrees C and at room temperature.     

用酶标抗体免疫组化法测定性交后阴道内容物中精子的ABO血型

应用间接酶标抗体免疫组化法测出了53例新鲜精液、5例陈旧精斑及40例阴道分泌液中的精子与阴道脱落上皮细胞的ABO血型,30例精子与不同血型分泌型阴道分泌液孵育,未发现精子吸附阴道液中血型物质的现象,同时发现人类睾丸曲精细管中部份生精细胞、精子细胞,精子;直细精管部份上皮细胞、精液、精子;睾丸网大部份上皮细胞及副睾管中的精液与精子均含ABH抗原,故认为精子上的ABH抗原主要是精子固有抗原,13例性交后阴道内容物中精子的ABO型测定结果:7例与供者血型吻合,6例不吻合。6例中5例从O型精子中测出了女方分泌型阴道分泌液中的A或AB物质,1例B型精子未测出B及H抗原,文中对这种现象进行了讨论。     

Determination of the Lewis blood group substances in stains of forensically relevant body fluids

Forensic investigations often demand a clear definition of secretor status. Lewis-typing of secretion stains may help to verify non-secretor results and to identify mixtures of secretions from Le (a-b-) persons and secretors (or non-secretors). Furthermore it gives an additional check on secretor status, determined by ABO-grouping. Few problems may arise, when testing prepared saliva or semen stains. Therefore our interest was focussed on the possibility of Lewis-typing in stains appearing in forensic case work such as cigarette tips, stamps and envelope flaps, semen stains and vaginal swabs, nasal secretion, sweat and urine stains. All stains with the exception of sweat and urine were successfully Lewis-typed. In saliva stains Lewis substances could be determined even after 5 years and in semen stains for at least up to 40 days.     

Gm/Km determination in sperm traces

In the forensic laboratories of the Federal Republic of Germany and West-Berlin 23 different semen stains and in our own laboratory 20 semen stains were typed in the gm/km-system doing 125 and 61 (own) test respectively. Examination was carried out by means of the haemagglutination method, which has been used successfully in typing bloodstains. Our critical assessment based on earlier experiences with semen stains was now confirmed and statistically evaluated: typing was successful in about 35-50% of the tests, but besides false-negative results, there was also a considerable percentage (4-10%) of false-positive ones. Therefore for the present it seems best to exclude the gm/km-typing of secretion stains from forensic investigations in order to avoid false incriminations or exonerations of suspects.     

Evaluation of prostate-specific antigen (PSA) membrane test assays for the forensic identification of seminal fluid.

Prostate specific antigen (PSA, also known as p30), a glycoprotein produced by the prostatic gland and secreted into seminal plasma, is a marker used for demonstrating the presence of seminal fluid. Methods for the detection of PSA include Ouchterlony double diffusion, crossover electrophoresis, rocket immuno-electrophoresis, radial immunodiffusion, and ELISA. The extremely sensitive ELISA technique can detect PSA in concentrations as low as approximately 4 ng/mL. However, all these techniques are cumbersome and time consuming to perform in forensic laboratories, especially when only a few samples per week are processed. Various membrane tests are currently used in clinical settings to screen a patient's serum for the presence of PSA at levels greater than 4 ng/mL. In this study we evaluated three immunochromatographic PSA membrane tests by analyzing semen stains stored at room temperature for up to 30 years, post-coital vaginal swabs taken at different time after intercourse, semen-free vaginal swabs, and various female and male body fluids, including urine. The data demonstrate that PSA membrane test assays offer the same sensitivity as ELISA-based tests and provide a rapid approach for the forensic identification of seminal fluid. Furthermore, when the supernatant from a DNA extraction is used for the assay, there is essentially no DNA consumption for determining the presence of PSA in a forensic sample.     

Experiences with single locus DNA probes in casework.

DNA profiling in this laboratory has been employed primarily in cases of sexual assault and the largest category of items examined has been internal vaginal swabs. 79% of these gave a profile which was different from that of the victim. Results have been obtained from swabs taken up to 70 h after intercourse. In cases where DNA results were obtained, one or more suspects were excluded in 29% of the cases.     

Effects of presumptive test reagents on the ability to obtain restriction fragment length polymorphism (RFLP) patterns from human blood and semen stains.

Some of the commonly used presumptive test reagents for identification of blood and semen could potentially affect the recovery of intact high-molecular-weight deoxyribonucleic acid (DNA) from evidentiary samples. Thus, the capability of performing restriction fragment length polymorphism (RFLP) analysis on evidentiary samples could be compromised. In order to investigate the potential effects of presumptive test reagents on the DNA present in these samples, bloodstains on cotton and glass were exposed directly to luminol, benzidine, phenolphthalein, o-tolidine, and leucomalachite green, while semen stains and vaginal swabs containing semen were exposed directly to bromochloroindolyl phosphate (BCIP) and sodium thymolphthalein monophosphate (STMP) reagents. The yield gels for DNA quality and quantity and RFLP results indicated that bloodstains exposed to luminol, benzidine dissolved in ethanol, and phenolphthalein, as well as semen stains and vaginal swabs exposed to BCIP and STMP yield RFLP patterns consistent with that of the uncontaminated control. Except for the phenolphthalein treatment, the quantity of extractable, high-molecular-weight DNA obtained was comparable with that of untreated stains. Therefore, evidentiary material purposely or inadvertently contaminated with these reagents can be successfully typed. However, stains exposed to benzidine dissolved in glacial acetic acid, leucomalachite green, and o-tolidine failed to yield high-molecular-weight DNA or to produce any RFLP patterns.     

Persisting fetal microchimerism does not interfere with forensic Y-chromosome typing

Forensic Y-chromosome typing applies Y-chromosomal polymorphisms to the analysis of male/female mixed stains such as vaginal swabs in rape cases. The sensitivity of this approach exceeds that of cytological techniques combined with autosomal DNA typing. Y-chromosome typing is based on the assumption that Y-chromosomal DNA found in tissue or secretions of women must originate from a male individual, usually the perpetrator. Nevertheless, it was shown recently that fetal cells can migrate into the female body during pregnancy and can persist for decades ("persisting fetal microchimerism"). The body of a woman after a pregnancy with a male embryo can thus display a small fraction of fetal cells with Y-chromosomes. Using high sensitivity PCR protocols (reamplification with nested primers and up to 60 PCR cycles) fetal cells were previously identified in a number of maternal tissues including skin, blood, muscle and solid organs. It is, however, not clear at present, whether these cells can occur in vaginal secretions, and whether they are capable of producing false positive results in forensic Y-chromosome typing. To evaluate these questions, 66 blood samples of women with at least one son and nine vaginal swabs of women without sexual intercourse in the last 2 weeks were amplified for a stretch of the SRY gene. Eight thyroid gland tissues with already established male fetal microchimerism were used as positive control samples. Blood samples of 10 young girls without history of pregnancy were used as negative controls. Using a PCR with 10 ng of extracted DNA and 30 PCR cycles ("routine sensitivity assay") none of the samples yielded positive results. However, in a PCR with 200 ng of extracted DNA and 45 PCR cycles ("high sensibility assay"), 14% of the blood samples of mothers and 33% of the vaginal swabs amplified for SRY. Our results thus show that increasing the sensitivity of the PCR method and the amount of template DNA produce positive results while protocols used for routine Y-chromosomal typing with small amounts of DNA (approximately 10 ng of DNA) and with a limited number of PCR cycles (approximately 30) can clearly eliminate this peril.     

The application of a simple RIA technique for the detection of 19-OH F1 alpha/F2 alpha prostaglandin, a specific semen marker, in semen contaminated vaginal swabs: time since intercourse studies

The specificity of the 19-OH F1 alpha/F2 alpha prostaglandin antisera for the detection of semen in seminal/vaginal mixtures, has been evaluated. Using a parallel curve test we found that the antibody showed a high specificity for these seminal prostaglandins in seminal/vaginal mixtures at concentrations of between 2 pg and 40 pg/100 microliter. The precision of the assay has been improved by the use of a donkey-anti-rabbit ferritin-bound second antibody. The application of this detection system makes it possible to complete an assay within 4.5 h. A survey of 50 semen-free vaginal swabs obtained from 3 donors, taken throughout the menstrual cycle, showed no trace of these prostaglandins. They were also not detected in the vaginal secretions of two further donors who were undergoing medication. Using only 10-microliter aliquots of a seminal/vaginal swab extract, prepared in 500 microliter, it was possible to detect semen up to approx. 80 h after one sexual act.     

用等电聚焦酶免疫分析法检测人类精斑GC表现型

本文用IEF结合使用过氧化物酶标记第二抗体的酶免疫分析法检测了17名键康成年男性的精液(斑)和唾液斑及10名健康成年女性的阴道分泌液中的GC表现型。结果发现17份人类精斑均可测出三种GC蛋白普通表现型。在10份阴道液中测出一份样本的GC表现型,3份样本有不甚清楚的GC带,不能定型,其他样本均无GC带。17份唾液斑未测出GC。本法的灵敏度(0.675ng)比文献报道的用过氧化物酶标记第二抗体的酶免疫分析(5.6ng)高。     

Is it possible to predict the origin of epithelial cells? – A comparison of secondary transfer of skin epithelial cells versus vaginal mucous membrane cells by direct contact

In alleged sexual assault and rape cases, the focus has often been to collect samples from the victim's body, for detection of body fluids or skin cells from the offender. But in many cases intimate body samples from the perpetrator(s) can also be informative. However, in cases where the female victim claims vaginal penetration, the defendant may display an alternative explanation to the DNA findings, i.e. that the victim’s skin cells has been secondarily transferred to his penis. We hypothesized that female DNA will be detected in a significantly greater amount on swabs from penis after intercourse than after secondary transfer by skin contact.Fourteen male-female couples were recruited to test the above hypothesis, by collecting penile swabs from 3 specified anatomical locations: Glans, shaft, and the coronal sulcus, after two different situations: Vaginal intercourse and secondary transfer of epithelial cells by skin contact. The results show that penile swabs following intercourse produce significantly higher DNA concentrations than after secondary transfer by skin contact. Our results, indicates which of the anatomical regions is best suited for sampling. The DNA profiling results show a preponderance of female profiles over male profiles following intercourse compared to secondary skin contact.Based on these data, it is possible to make a statistical model to distinguish between samples taken after intercourse and samples taken after secondary transfer by skin contact based on the amount of female DNA and mixture proportion (Mx) between female and male DNA in samples collected from penis swabs.     

Identification and isolation of male cells using fluorescence in situ hybridisation and laser microdissection, for use in the investigation of sexual assault

In cases of sexual assault involving an azoospermic assailant, vaginal swabs taken from the victim may fail to provide an autosomal DNA profile with which to search a suspect database, as the signal from any male cells present would be masked by that from the overwhelming number of female cells collected on the swab. Here, we describe a method of visually identifying diploid male cells in such samples using fluorescence in situ hybridisation, and selectively harvesting them by means of laser microdissection. This combination of techniques was tested on 26 post-coital vaginal swabs taken at a range of times after intercourse; the collected cells were then subjected to a simple lysis procedure and DNA was amplified using the AmpFlSTR^® SGMPlus^® multiplex under low copy number conditions. Useful DNA profiles were generated from samples taken up to 24 h after intercourse.     

Validation and casework application of a Y chromosome specific STR multiplex

A series of validation experiments was performed for a Y chromosome specific STR multiplex system following the suggestions made by the Technical Working Group DNA Analysis Methods (TWGDAM). The multiplex PCR products were detected on Perkin-Elmer 373 and 377 automated sequencers using two labeling colors. No problems regarding the stability, robustness and sensitivity of the Y STR multiplex were observed. Mixture studies revealed a cut off rate similar to autosomal STRs for mixtures of male DNAs and no interference of any female admixture. The comparison of the Y STR results to the autosomal typing results for 56 nonprobative semen stains and swabs, showed a slightly higher success rate in detecting the semen donor's alleles for the Y STR multiplex. Two examples are shown to illustrate the usefulness of Y STR typing for DNA mixtures. In one case the Y STR results confirmed an isolated exclusion; in the other case, the interpretation of a mixture was clarified since the Y STR results proved the presence of DNA from at least two semen donors. Y STR typing is a valuable addition to the forensic DNA testing panel.     

Results of forensic medicine victim/perpetrator studies following sex offenses

39.1% of all clinical examinations performed at the institute for legal medicine in Hannover during a period of 9 years were carried out after sexual assault (229 out of 585 cases between 1979-1987). In 74.4% of all women extragenital injuries and in 26.2% of the cases genital lesions could be observed. Vaginal swabs showed sperm at a rate of 44%; spermatozoa could be observed at a maximum delay between assault and examination of 36 hours. Three male victims of sexual assaults and 37 male defendants were examined. On male victim presented superficial lesions of the anus. In 27 penis swabs there could be found spermatozoa (4x), vaginal epithelia (2x) and red blood cells (1x; after intercourse during menstruation).     

PCR法对HLA-DQ_α基因的分型及其在性犯罪鉴定中的应用

本文应用 PCR 法及 ASO 探针斑点杂交技术,对100例无关个体血液 DNA 及10例性犯罪案件混合斑中精子 DNA 进行了 HLA-DQα基因的扩增及其 DNA 分型。结果正常人0.1～0.3μgDNA 就能满足 DQα基因扩增的需要。在100例个体中可以观察到由4种等位基因组成的10种 DQα基因型。10例不同条件的混合斑中精子 DNA 经30～60次扩增后与 ASO 探针杂交均能准确地判定 DQα基因型。HLA-DQα是个体识别能力较强的遗传标志。本文为性犯罪中精子来源的个体识别提供了一个新方法,具有一定的实用价值。     

Lactate dehydrogenase isozymes in vaginal swab extracts: A problem for the identification of menstrual blood

Extracts of vaginal swabs free of both blood and semen, collected from three donors throughout several menstrual cycles, have been examined by cellulose acetate membrane electrophoresis for the presence of lactate dehydrogenase (LDH) isozymes. LDH activity, predominantly in the form of LDH-5 was detected in some extracts. Mixtures of these particular extracts with peripheral blood gave LDH patterns similar to those observed for menstrual blood. The results indicate that LDH isozyme patterns cannot be used to differentiate between stains of menstrual blood and bloodstains that have become mixed or contaminated with vaginal secretions.     

Isolation of deoxyribonucleic acid (DNA) from saliva and forensic science samples containing saliva.

Saliva and saliva-stained materials were examined as potential sources of deoxyribonucleic acid (DNA) for DNA analysis and identity testing. In this paper, the authors demonstrate that DNA was isolated and DNA banding patterns suitable for DNA typing were obtained from fresh saliva and various saliva-stained materials, such as envelopes, buccal swabs, gags, and cigarettes. Furthermore, DNA and DNA banding patterns were obtained from actual forensic evidentiary samples containing mixed saliva/semen stains. The DNA banding patterns obtained from saliva or saliva-stained material were indistinguishable from the patterns obtained from blood or hair from the same individual. Intact DNA was readily isolated and DNA banding patterns were obtained from saliva stored at -20 degrees C and dried saliva stains stored under varying conditions. We conclude that saliva and saliva-stained material can be good sources of DNA for analysis and for DNA typing in certain forensic settings.