Detection Of Semen Research Articles

The detection of blood, semen and saliva through fabrics: A pilot study

This study aimed to identify if biological material could be detected on the opposite side to deposition on fabric by commonly used presumptive and/or secondary tests. Additionally, this study aimed to ascertain if there is a difference in the DNA quantity and quality from samples obtained from both sides of the same substrate: cotton, polyester, denim, or combined viscose and polyester swatches. Blood, semen, or saliva (25 μL) was deposited on one side of 5 replicates of each fabric type and left for 24 h. Blood swatches were tested using Hemastix® and the ABACard® HemaTrace® immunoassay, semen swatches were tested using acid phosphatase (AP) reagent, the ABACard® p30® immunoassay and hematoxylin and eosin staining, and saliva swatches were tested using Phadebas® paper and the RSID-Saliva™ immunoassay. Both sides of each swatch were separately wet/dry swabbed and subjected to DNA analysis. Blood was able to be detected on the underside of all fabrics using both tests. Semen was able to be detected on the underside of swatches using the presumptive AP test but not p30®, and sperm was rarely observed. Saliva was able to be detected by RSID-Saliva™ but not Phadebas® paper when the underside of swatches were tested. Across all biological materials, DNA was able to be recovered from the top side of all 60 swatches. For the underside, DNA was able to be recovered from 54 swatches. Of the 6 swatches that DNA was unable to be recovered from, one sample was from semen and the rest were from saliva. This study has demonstrated that DNA and components of interest in forensically relevant biological material can be recovered from the opposite side to where it was originally deposited, and that observing biological material and/or DNA on one side of fabric does not definitively indicate direct deposition on that side.

The impact of infrared radiation, solar radiation, and burial exposure on the efficacy of forensic immunoassay testing for blood, semen, and saliva

Determining the biological source of a stain can be important information for both investigators and the judiciary in criminal cases. Immunochromatographic assays are commonly used in forensic science for the identification of human biological material. It has previously been demonstrated that various environmental, thermal and chemical insults can affect the efficacy of ABAcard® HemaTrace® in the detection of human blood. In this study, the efficacy of three tests – ABAcard® HemaTrace®, ABAcard® p30, and RSID™-Saliva – was determined for the detection of blood, semen, and saliva respectively, after the fluids had been exposed to adverse environmental conditions. Each biological fluid was deposited on cotton swatches and exposed to infrared (IR) light using a 100 W heat lamp emitting IR light between 620 and 750 nm and heat of 32° for 24, 36 and 48 h. Cotton swatches bearing biological fluids were also buried in outdoor soil for 3, 4 and 5 weeks. To test common forensic scenarios where biological material may be exposed to solar light, samples were placed on a car bonnet and left for 24, 36 and 48 h. ABAcard® HemaTrace® was able to detect haemoglobin in blood that had been exposed to IR and solar light up to 48 h. False negative ABAcard® HemaTrace® results were obtained from 60 % of blood samples buried for 3 and 4 weeks, and 80 % of blood samples buried for 5 weeks. ABAcard® p30 was able to detect p30 in semen that had been exposed to IR and solar light up to 48 h, except for one false negative after 48 h of IR exposure. False negative ABAcard® p30 results were obtained from all semen samples buried for 3, 4 and 5 weeks. RSID™-Saliva was able to detect α-amylase in saliva in all instances, with no false negative results observed. The findings from this study highlight the need to consider the context in which human blood, semen and saliva are found when reporting on negative immunoassay results.

Assessment of Blood and Semen Detection and DNA Collection from Swabs up to Three Months after Deposition on Five Different Cloth Materials.

Body fluid identification plays a crucial role in criminal investigations. Because of their presence in many cases, blood and semen are the most relevant body fluids in forensic sciences. Based on antigen-antibody reactions binding unique proteins for each body fluid, serological assays represent one of the most rapid and highly specific tests for blood and semen. Currently, few studies have assessed the factors affecting body fluid identification by applying these assays. This work aimed to study the effect of different fabrics from clothes and time since deposition on identification through immunochromatographic tests for blood and semen, DNA isolation, and STR profiling from these samples. Body fluids were deposited on black- and white-dyed denim and cotton fabrics, and on leather. Afterward, blood and semen were sampled at 1 day, 30 days, and 90 days after deposition and identified by using the SERATEC® HemDirect Hemoglobin Test and the PSA Semiquant and SERATEC® BLOOD CS and SEMEN CS tests, respectively. Laboratory and crime scene tests presented similar performances for the detection of blood and semen stains on every tested fabric. No differences were found on band intensities between timepoints for all fabrics. It was possible to recover and identify blood and semen samples up to three months after deposition and to obtain full STR profiles from all the tested fabrics. Both body fluid STR profiles showed differences in their quality between 1 and 90 days after deposition for all fabrics except for black cotton for semen samples. Future research will expand the results, assessing body fluid identification on other substrates and under different environmental conditions.

Assessment of body fluid identification and DNA profiling after exposure to tropical weather conditions.

Despite current advances in body fluid identification, there are few studies evaluating the effect of environmental conditions. The present work assessed the detection of body fluids, blood, semen, and saliva, through lateral flow immunochromatographic (LFI) tests, exposed to tropical weather conditions over time, also evaluating the possibility of obtaining STR (short tandem repeat) profiles and identifying mitochondrial DNA (mtDNA) polymorphisms. Blood, semen, saliva samples, and mixtures of these fluids were deposited on polyester clothes and exposed to open-air tropical weather conditions for 1 month. The test versions from LFI (SERATEC®, Germany) Lab and crime scene (CS) used for the detection - one per each body fluid type - demonstrated that it is possible to identify body fluids and their mixtures up to 14 days after deposition. At 30 days, blood and semen were detected but not saliva. Full STR profiles were obtained from 14-day-old blood samples, and partial profiles were obtained from the remaining samples. It was possible to sequence mtDNA in the samples previously analyzed for STR profiling, and haplogroups could be assigned. In conclusion, this study demonstrated for the first time the possibility of body fluid identification and DNA profiling after exposure to tropical weather conditions for 1 month and also demonstrated the value of mtDNA analysis for compromised biological evidence.

Expanding the scope of methylation-sensitive restriction enzyme (MSRE) PCR for forensic identification of body fluids through the novel use of methylation-dependent restriction enzymes (MDRE) and the combination of autosomal and Y-chromosomal markers

Methylation-sensitive/-dependent restriction enzyme (MSRE/MDRE) PCR can be performed to detect hypomethylated or hypermethylated CpG sites. With the combined use of different tissue-specific CpG markers, MSRE/MDRE-PCR leads to tissue-specific methylation patterns (TSMPs), enabling the correlation of DNA samples to their source tissue. MSRE/MDRE assays can use the same platform as forensic STR typing and offer many advantages in the field of forensic body fluid detection. In the present study, we aimed to establish MSRE assays for the detection of blood, saliva, vaginal secretion, and semen, using markers from literature and from our own database search. We designed two different MSRE test-sets, which include two novel Y-chromosomal non-semen markers, and enable differentiation between female and male non-semen samples. Furthermore, we established an MSRE/MDRE semen approach, which includes only Y-chromosomal non-semen and semen markers. This Y-semen multiplex PCR utilizes the novel combination of the methylation-sensitive enzyme SmaI and the methylation-dependent enzyme GlaI, which enables more sensitive detection of male body fluids within male/female DNA mixtures. Our validation tests confirmed that MSRE/MDRE assays exhibit high sensitivity, similar to that of STR typing.

Overcoming obstacles: Analysis of blood and semen stains washed with different chemicals with ATR-FTIR

IntroductionBlood and semen stains are the most common biological stains encountered at crime scenes. The washing of biological stains is a common application that perpetrators use to spoil the crime scene. With a structured experiment approach, this study aims to investigate the effects of washing with various chemicals on the ATR-FTIR detection of blood and semen stains on cotton. Materials and methodsOn cotton pieces, a total of 78 blood and 78 semen stains were applied, and each group of six stains was immersed or mechanically cleaned in water, 40% methanol, 5% sodium hypochlorite solution, 5% hypochlorous acid solution, 5 g/L soap dissolved pure water, and 5 g/L dishwashing detergent dissolved water. ATR-FTIR spectra gathered from all stains and analyzed with chemometric tools. Results and discussionAccording to performance parameters of developed models, PLS-DA is a powerful tool for discrimination of washing chemical for both washed blood and semen stains. Results from this study show that FTIR is promising for use in detecting blood and semen stains that have become invisible to the naked eye due to washing of the findings. ConclusionOur approach allows blood and semen to be detected on cotton pieces using FTIR combined with chemometrics, even though it is not visible to the naked eye. Washing chemicals also can be distinguished via FTIR spectra of stains.

Identification of Human Semen (Spermatozoa) through Different Methods in Forensic Investigation

The presence of seminal stains is very important in crime involving sexual offence. Semen detection is an important factor in forensic investigation to confirm sexual assault in cases of rape. Forensic science laboratory received large numbers of cases involve in sexual offenses for examination and detection of seminal fluid in the exhibits sent by different investigating agencies. A Forensic laboratory receives different types of exhibits for examination of the presence of seminal stains in the exhibits like, garments, cotton swabs, smear in a glass slide, liquid and dry semen, semen mixed with other body fluids, and other articles related to the case. Various methods have been developed in forensic science for identification of semen (sperm). This paper focuses on the basic knowledge of collection seminal stains from the crime scene and detection procedure of human semen (sperm) from the various exhibits in the forensic laboratory. This paper also proposed practical approaches and guideline to help forensic, and law enforcement professionals to deal with the crime scene seminal evidence to avoid contamination, degradation, and loss of the value of the seminal evidence. Keywords: Forensic Science, Spermatozoa, Seminal fluid, Identification of semen, Sexual assaults.

A simplified protocol for the detection of blood, saliva, and semen from a single biological trace using immunochromatographic tests

The detection of body fluids (e.g., blood, saliva or semen) provides information that is important both for the investigation and for the choice of the analytical protocols. Because of their sensitivity, specificity, as well as their simplicity of use, immunochromatographic tests are widely applied. These tests target different body fluids and generally require specific buffer solutions. If one needs to investigate whether the material is of a specific nature (e.g., blood), this is fine. However, if the material can also contain other material (e.g., saliva or semen) then the use of different tests can be problematic. Indeed, if the different tests require different buffers, it will not be possible to perform all tests on the exact same specimen.In this study, we assess the use of the RSID™-universal buffer to perform three immunochromatographic tests (HEXAGON OBTI, RSID-saliva, and PSA Semiquant) as well as spermatozoa detection. We use the same eluate for the detection of all three body fluids. The proposed protocol provides similar results to those obtained when each test is conducted independently. Furthermore, it does not affect the quality of the DNA profiles. The main advantage of this protocol is that the results of the presumptive test(s) and of the DNA analyses are representative of the exact same specimen.

Establishment of the new semen identification method and the examination to practical introduction

Recently, AXO Science released STK Sperm Tracker Lab (STK sheet) and STK Sperm Tracker SPRAY (STK spray) to identify human semen stains. In this study, we examined the STK sheet and STK spray for their specificity to detect human semen, sensitivity, effects on DNA, and response to old semen samples. Additionally, STK sheet was examined for optimal crimping time depending on the type of fabric. STK spray was examined through assessing the effect of ultraviolet (UV) radiation after spraying. As a result of this study, STK sheet and STK spray were found to exhibit high specificity for the detection of human semen. These reagents did not affect the yield of extracted DNA or its degradation. STK sheet and STK spray can detect semen up to 1/25th and 1/100th dilutions, respectively. Both STK sheet and STK spray can react with semen samples left at room temperature for over a year. We found that the crimping time on STK sheet differs depending on the type of fabric, and the exposure to UV radiation for an hour after using STK spray does not affect DNA degradation. Conclusively, both STK sheet and STK spray are suitable to identify the human semen stains.

Development and validation of a custom panel including 183 Y‐SNPs for Chinese Y‐chromosomal haplogroups dissection using a MALDI‐TOF MS system

Y-chromosome SNP haplogroups exhibit geographic structuring in many populations around the world. Therefore, Y-chromosome haplogroups have been widely used to infer paternal biogeographical ancestry and high-resolution paternal lineage classification. In the present study, we designed a customized panel containing 183 Y-SNPs based on previous studies and evaluated the genotyping performance and repeatability, concordance, sensitivity, and ability of analysing case-type samples using a MALDI-TOF MS platform. The average call rate for duplicate typing of any one SNP in the panel was 97.0%. In the concordance and accuracy study, the results of haplogroup designation obtained from MALDI-TOF MS platform were fully consistent with those obtained from the next-generation sequencing (NGS) platform. The optimal amount of template DNA in the PCR seemed to be 10ng. However, if less DNA (≥156.25pg) was available, it was still possible to obtain meaningful haplogroup information. For the application part, this panel could be applied for the detection of blood, semen, and buccal swabs samples. Particularly, blood stain on FTA card samples could be dissected by direct PCR amplification on the MALDI-TOF MS platform. Besides, 371 unrelated male individuals from four Chinese ethnic groups (Han, Hui, Mongolian, and Kazak) were detected using this panel. Total 78 terminal haplogroups were found and the haplogroup diversity was 0.933576. The results demonstrate that this panel could be an accurate, fast, and cost-effective method for database construction where the amount of sample material is less of a concern and when the cost of the assay is taken into consideration.

Rapid Stain Identification (RSID-TMSemen): A rapid tool for seminal fluid detection

Introduction: The identification of semen stain is one of the most common human stains that can provide crucial information for crime scene reconstruction and forensic investigation. In sexual assault cases semen identification helps to support or refute victim’s allegations, it also provides a material for DNA analysis. The rapid Stain Identification of Human Semen (RSIDTM -Semen) bioassay is designed to detect specifically the presence of human semenogelin. It does not cross‐ react with other human or nonhuman tissues. Aim: To assess the efficacy of RSIDTM – Semen strip test for the detection of human semen under some different variables (different fabrics, different time intervals and mixed with vaginal secretions). Methodology: Semen samples were collected from four male participants; each sample was divided into two portions; one used for semen only test group and the other mixed with vaginal secretions for the mixed test group. Vaginal swabs were carried out from the four female participants using cotton, linen or nylon-tipped plastic rods (2 swabs from each female). One of the fabrics tipped vaginal swab was mixed with semen for the mixed test group and the other used as a positive control group to test the sensitivity and specificity of the RSIDTM – Semen strip. The semen samples were deposited over different fabrics at the same time. All the samples were left to dry for 15 minutes at room temperature (summer) then extracted and analyzed. Each of the previous groups, was categorized into 5 subgroups (a, b, c, d and e) according to the time interval of semen extraction (zero (on the spot), 2, 4, 6 and 10 days respectively). Results: Semen could be identified in 100% of tested samples of the semen only group as well as of the combined semen and vaginal secretions group over cotton and linen fabrics at all the different tested time intervals. However, semen extracted from nylon fabric was identified in tested samples of the semen only group and of the combined semen and vaginal secretions group only at zero time only and couldn’t be identified at the rest of tested time intervals. Conclusion: The current study evidenced that the new RSIDTM -semen kit is a reliable method for semen identification over different types of fabrics even in the presence of vaginal secretions. It also persists up to 10 days except on nylon fabric.

Inhibition of acid phosphatase detection in mixed semen-blood training samples by anti-coagulants present in blood collection tubes

Acid phosphatase detection using fast blue or fast black reagent is routinely performed at the RCMP National Forensic Laboratory Services as a presumptive test for semen. In training exercises, samples consisting of semen mixed with blood were reported to yield negative results with the fast black reagent. To determine the cause of the inhibition, mixed semen-blood stains were prepared using different blood sources, anti-coagulants, and layering techniques, before being tested with the fast blue or the fast black reagent. The anti-coagulant sodium fluoride (NaF) was shown to cause false negative results with the fast black reagent and to impair detection when using the fast blue reagent while no inhibition was observed when dipotassium EDTA (K2 EDTA) was used as anti-coagulant. Four different toothpastes containing fluoride were also tested for potential inhibition of semen detection. Inhibition was observed when semen was mixed with three of the undiluted toothpastes but not with diluted toothpastes (1 in 20 in water). These findings highlight the importance of using appropriate blood sources when preparing mixed semen-blood stains for the purpose of training and proficiency testing in a forensic laboratory. However, forensic casework samples are not expected to contain NaF at the inhibiting levels.

Rapid stain biomarker: A novel tool for forensic detection of semen (effect of time, different fabrics and vaginal secretions on its reliability)

Abstract Background The identification of semen stain is one of the most common human stains that can provide crucial information for crime scene reconstruction and forensic investigation. In sexual assault cases semen identification helps to prove victim’s allegations it also provides a material for DNA analysis that generate the genetic profile of the alleged suspect. The rapid Stain Identification of Human Semen (RSIDTM-Semen) bioassay is designed to detect specifically the presence of human semenogelin. Test development is completed within 10 minutes and can detect as little as 2.5 nL of human semen and it does not cross-react with other human or nonhuman tissues. The detection protocol can be completely integrated into the procedures for DNA extraction and analysis. Aim To assess the efficacy of RSIDTM – Semen strip test for the detection of human semen under some different variables (different fabrics, different time intervals and mixed with vaginal secretions) in order to be used in the routine forensic work of sexual assault cases and for further personal identification. Methodology: Semen samples were collected from four male participants. Vaginal specimens were collected from four female participants on cotton, linen or nylon-tipped swabs (2 swabs from each female). Each semen sample was divided into two portions; one used for semen only test group and the other mixed with vaginal secretions for the mixed test group. One of the fabrics tipped vaginal swab was mixed with semen for the mixed test group and the other used as a positive control group to test the sensitivity and specificity of the RSIDTM – Semen strip. The semen samples were deposited over different fabrics at the same time. All the samples were left to dry for 15 minutes at room temperature then extracted and analyzed according to the protocol designed for The Rapid Stain Identification Test (RSIDTM – Semen). The collected samples were studied as two test groups and one control group. Each of the previous groups, was categorized into 4 subgroups (a, b, c and d) according to the time interval of semen extraction (zero (on the spot), 2, 4, 6 and 10 days respectively). Results Semen could be identified in 100% of tested samples of the semen only group as well as of the combined semen and vagina group over cotton and linen fabrics at all the different tested time intervals. However, semen extracted from nylon fabric was identified in tested samples of the semen only group and of the combined semen and vagina group only at zero time only and couldn’t be identified at the rest of tested time intervals. Conclusion the current study evidenced that the new RSIDTM-semen kit is a reliable method for semen identification over different types of fabrics even in the presence of vaginal secretions. It also resists environmental factors up to 10 days.

Clinical Pattern of Inflammatory bowel disease in central reigon, Saudi Arabia

Abstract Background The identification of semen stain is one of the most common human stains that can provide crucial information for crime scene reconstruction and forensic investigation. In sexual assault cases semen identification helps to prove victim’s allegations it also provides a material for DNA analysis that generate the genetic profile of the alleged suspect. The rapid Stain Identification of Human Semen (RSIDTM-Semen) bioassay is designed to detect specifically the presence of human semenogelin. Test development is completed within 10 minutes and can detect as little as 2.5 nL of human semen and it does not cross-react with other human or nonhuman tissues. The detection protocol can be completely integrated into the procedures for DNA extraction and analysis. Aim To assess the efficacy of RSIDTM – Semen strip test for the detection of human semen under some different variables (different fabrics, different time intervals and mixed with vaginal secretions) in order to be used in the routine forensic work of sexual assault cases and for further personal identification. Methodology: Semen samples were collected from four male participants. Vaginal specimens were collected from four female participants on cotton, linen or nylon-tipped swabs (2 swabs from each female). Each semen sample was divided into two portions; one used for semen only test group and the other mixed with vaginal secretions for the mixed test group. One of the fabrics tipped vaginal swab was mixed with semen for the mixed test group and the other used as a positive control group to test the sensitivity and specificity of the RSIDTM – Semen strip. The semen samples were deposited over different fabrics at the same time. All the samples were left to dry for 15 minutes at room temperature then extracted and analyzed according to the protocol designed for The Rapid Stain Identification Test (RSIDTM – Semen). The collected samples were studied as two test groups and one control group. Each of the previous groups, was categorized into 4 subgroups (a, b, c and d) according to the time interval of semen extraction (zero (on the spot), 2, 4, 6 and 10 days respectively). Results Semen could be identified in 100% of tested samples of the semen only group as well as of the combined semen and vagina group over cotton and linen fabrics at all the different tested time intervals. However, semen extracted from nylon fabric was identified in tested samples of the semen only group and of the combined semen and vagina group only at zero time only and couldn’t be identified at the rest of tested time intervals. Conclusion the current study evidenced that the new RSIDTM-semen kit is a reliable method for semen identification over different types of fabrics even in the presence of vaginal secretions. It also resists environmental factors up to 10 days. Background: Inflammatory bowel disease (IBD) is A chronic inflammatory disorder of the gastrointestinal tract (GIT). IBD comprises Crohn’s disease (CD) and Ulcerative Colitis (UC). Patients with CD and UC may present with variety of clinical presentations according to the activity of the disease. The treatment of IBD varies according to degree of activity. The demographics and clinical patterns of IBD have not been adequately studies in Saudi Arabia. Thus, the current study investigated the clinical presentation, course and outcome of IBD in a hospital in the Central region, Saudi Arabia. Methodology This prospective study included 92 patients from December 1, 2017, to August 31, 2018. The study constituted clinical history, screening through surveys that consisted of open ended and closed ended questions, and physical and laboratory assessment. Result There was no significant gender difference presents by male to female (M: F) 20:21 in UC and 23:28 in CD. The study showed that the most affected age group was the 4th decade in age group 31 to 40 years old represent that 56%. The most common presenting symptoms in active ulcerative colitis and Crohn’s disease were diarrhea, abdominal pain , weight loss, headache and fever. The study patients presented in different stages according to Montreal classification with the highest prevalence in Montreal stage two by 16.30% in UC and 22.82% in CD. Among patients with diarrhea, the vast majority due to infectious cause followed by UC the CD. Arthralgia’s, arthritis and ophthalmic manifestations were the most frequent extra-intestinal manifestations. Conclusion As progression of IBD in Saudi Arabia the health organization should research more in IBD and the cause of increase it’s incidence

Progress in Research on Sperm DNA Fragmentation.

With the increasing incidence of male infertility, routine detection of semen is insufficient to accurately assess male fertility. Infertile men, who have lower odds of conceiving naturally, exhibit high levels of sperm DNA fragmentation (SDF). The mechanisms driving SDF include abnormal spermatogenesis, oxidative stress damage, and abnormal sperm apoptosis. As these factors can induce SDF and subsequent radical changes leading to male infertility, detection of the extent of SDF has become an efficient routine method for semen analysis. Although it is still debated, SDF detection has become a research hotspot in the field of reproductive medicine as a more accurate indicator for assessing sperm quality and male fertility. SDF may be involved in male infertility, reproductive assisted outcomes, and growth and development of offspring. The effective detection methods of SDF are sperm chromatin structure analysis (SCSA), terminal transferase-mediated dUTP end labeling (TUNEL) assay, single-cell gel electrophoresis (SCGE) assay, and sperm chromatin dispersion (SCD) test, and all of these methods are valuable for assisted reproductive techniques. Currently, the preferred method for detecting sperm DNA integrity is SCSA. However, the regulation network of SDF is very complex because the sperm DNA differs from the somatic cell DNA with its unique structure. A multitude of molecular factors, including coding genes, non-coding genes, or methylated DNA, participate in the complex physiological regulation activities associated with SDF. Studying SDF occurrence and the underlying mechanisms may effectively improve its clinical treatments. This review aimed to outline the research status of SDF mechanism and detection technology-related issues, as well as the effect of increased SDF rate, aiming to provide a basis for clinical male infertility diagnosis and treatment.

Comparison of Crime-lite® 82S, Polilight® PL400 and Polilight® PL500 for the detection of semen and saliva stains

ABSTRACT Alternative light sources (ALS) are widely employed in forensic investigations for the identification of biological fluids, such as saliva and semen. While metal halide arc lamps are a common light source for many ALS, high intensity light-emitting diode (LED) globes are a more energy efficient alternative. To date, ALS operating with different light sources have not been evaluated against each other, and this study is the first to complete a side-by-side comparison of the arc lamps, Polilight® PL400 (PL400), Polilight® PL500 (PL500) and the LED-based Crime-lite® 82S (blue) (CL82S) for the detection of semen and saliva dilutions on various fabric materials. The absence or presence of fluorescence were scored independently by four experienced item examination scientists to reduce bias. The number of fluorescence stains detected using the CL82S (244 observations) was higher and brighter in intensity compared to those visualized using PL400 and PL500 (183 and 202 observations, respectively). Notably, dilutions of saliva which were not visible under PL400 and PL500 on a range of fabrics were detected under CL82S, which was statistically significant (p < 0.003). Taken together, CL82S is a better screening tool than the PL400 and PL500 for detection of dilute semen and saliva stains on various fabric types.

Integrating presumptive and confirmatory semen tests into DNA profiling of sexual assault evidence: a Philippine example

BackgroundIn sexual assault casework, the detection of semen on a sample supports an allegation of sexual contact and indicates the presence of DNA from a male source. Ideally, techniques employed should demonstrate high sensitivity and specificity and should be compatible with standard DNA typing procedures. To contribute recommendations for routine DNA tests of sexual assault cases in the Philippines, we evaluated the RSIDTM-Semen, an immunochromatographic test for human semenogelin (Sg), in parallel with the alternate light source (ALS) method using Mini BLUMAXX™ III and the acid phosphatase (AP) test using Seminal Fluid DISCHAPSTM.ResultsThe ALS detected semen diluted until 5% (v/v) fluid, whereas the AP assay was sensitive down to 0.5% (v/v). Non-blood-containing stains were visible under blue light except on dark-colored cloth. All semen-containing fluids including post-ejaculatory urine tested positive for AP and Sg. RSIDTM-Semen was sensitive down to 0.5 nL of semen; did not cross-react with blood, saliva, and female urine; and successfully detected Sg on the majority of post-coital samples tested. Complete short tandem repeat (STR) profiles of the semen donors were generated for most samples incubated in the RSIDTM-Universal Buffer (UB). However, we report an extraction efficiency of 15% for UB which can lead to partial profiles in already compromised samples.ConclusionWe recommend the use of ALS in visualizing stains present on surfaces and the AP test on blood-stained materials. These presumptive tests should be followed by RSIDTM-Semen test to confirm the presence of semen prior to DNA profiling.

The use of crime scene detection dogs to locate semen stains on different types of fabric

In sexual assault cases, the detection and identification of semen is extremely important as this type of evidence can be used as a source for investigative leads and contributes to case evidence. However, the detection of semen stains is often difficult, even indoors, because of different (environmental) factors, such as substrate type, coloured items and large search areas. In 2015, a project was initiated by the Dutch police to evaluate the feasibility of the use of detection dogs to locate semen stains in forensic practise. Since promising results were obtained, here, a double-blind study was designed to investigate how these detection dogs can optimally be implemented in the current work flow of crime scene investigators and to compare the dog’s sensitivity and specificity with current detection methods. The performance of the detection dogs was compared to three commonly used detection methods for semen, (i) forensic light sources (FLS), (ii) the RSID semen field kit and (iii) the enzymatic Acid Phosphatase (AP)-test on semen deposited at different types of fabrics. A 100% sensitivity and specificity for the detection of semen stains using the detection dogs was obtained, compared to an overall sensitivity and specificity of 76.3% and 100% for FLS, 81.6% and 100% for RSID-test, and 92.1% and 100% for AP-test, respectively. Especially, on fabrics with a pattern or interfering fluorescent properties, detection dogs demonstrated to be of additional value to locate the semen stains. We recommend to use the following order of testing, FLS, detection dog, AP-test and RSID test in a forensic workflow.

Spermine in semen of male sea lamprey acts as a sex pheromone.

Semen is fundamental for sexual reproduction. The non-sperm part of ejaculated semen, or seminal plasma, facilitates the delivery of sperm to the eggs. The seminal plasma of some species with internal fertilization contains anti-aphrodisiac molecules that deter promiscuity in post-copulatory females, conferring fitness benefits to the ejaculating male. By contrast, in some taxa with external fertilization such as fish, exposure to semen promotes spawning behaviors. However, no specific compounds in semen have been identified as aphrodisiac pheromones. We sought to identify a pheromone from the milt (fish semen) of sea lamprey (Petromyzon marinus), a jawless fish that spawns in lek-like aggregations in which each spermiating male defends a nest, and ovulatory females move from nest to nest to mate. We postulated that milt compounds signal to ovulatory females the presence of spawning spermiating males. We determined that spermine, an odorous polyamine initially identified from human semen, is indeed a milt pheromone. At concentrations as low as 10−14 molar, spermine stimulated the lamprey olfactory system and attracted ovulatory females but did not attract males or pre-ovulatory females. We found spermine activated a trace amine-associated receptor (TAAR)-like receptor in the lamprey olfactory epithelium. A novel antagonist to that receptor nullified the attraction of ovulatory females to spermine. Our results elucidate a mechanism whereby a seminal plasma pheromone attracts ready-to-mate females and implicates a possible conservation of the olfactory detection of semen from jawless vertebrates to humans. Milt pheromones may also have management implications for sea lamprey populations.

Repeatedly washed semen stains: Optimal screening and sampling strategies for DNA analysis

In many sexual assault cases, bedding and clothing are essential pieces of evidence that are screened for semen stains to gather DNA from the assailant. In some cases, these items have been washed before being seized and sent to the forensic lab. However, few data exist on the optimal methods for detecting and sampling semen stains on washed fabrics. In this paper, we used semen stains washed up to six times to evaluate the efficiency of commonly used screening methods for the detection of semen: alternate light source (ALS), acid phosphatase (AP), prostate specific antigen (PSA) and microscopy (sperm Hy-Liter™, SHL). We also assessed different washing conditions (detergents, washing machines, addition of bleach) and sampling methods (cutting and swabbing). The results show that some semen stain detection strategies, such as ALS, PSA, and SHL, are effective even when the item was washed multiple times. We also show that a complete genetic profile could be obtained from semen stains washed six times. Based on these findings, we present different strategies for the detection and sampling of semen stains depending on the circumstances of the case.