Developmental validation of the SPERM HY-LITER™ kit for the identification of human spermatozoa in forensic samples

The significance of prostate-specific antigen in forensic examinations of sexual violence: A case report

Prostate-specific antigen (PSA) tests are used in forensic science to perform rapid semen screening on vaginal swab samples from suspected victims of sexual assault. In some sexual assault cases, clothing or bedding is key evidence. A pre-trial investigation was launched following a complaint by an 85-year-old woman, who alleged that she had been raped by her 63-year-old son-in-law with whom she lives. Traces of seminal fluid were found in the vaginal swab (following a PSA test), and traces of seminal fluid, along with the victim's DNA and a partial DNA profile of the suspect, were found on the victim's underwear. The first-instance court (district court) found the man guilty and sentenced him to 3 years and 6 months of imprisonment for rape. Although PSA is produced in the prostate and secreted into seminal fluid, it is not exclusive to the prostate. PSA can be detected in women's bodies in various pathological conditions. In cases of sexual violence, the proper interpretation of laboratory tests is essential, taking into account all the circumstances of the incident as well as the victim's medical history.

A review on forensic analysis of bio fluids (blood, semen, vaginal fluid, menstrual blood, urine, saliva): Spectroscopic and non-spectroscopic technique

The accurate detection, identification, and analysis of biofluids at crime scenes play a critical role in forensic investigations. Various biofluids, such as blood, semen, vaginal fluid, menstrual blood, urine, and saliva, can be crucial evidence. In a murder case involving a knife attack, for instance, bloodstains from both the victim and perpetrator might be present. Sexual assault cases often involve the analysis of semen and vaginal secretions. Biofluid analysis employs a two-tiered approach: presumptive tests for initial identification and confirmatory tests for definitive analysis. This review article focuses on six key biofluids and their forensic significance. In this review, we comprehensively explore the relevant analytical techniques, including non-spectroscopic methods like immunoassays, spot tests, and cytokine profiling, alongside spectroscopic techniques such as Infrared (IR) spectroscopy, Mass Spectrometry (MS), and Raman Spectroscopy (RS).

From crime scene to courtroom: A review of the current bioanalytical evidence workflows used in rape and sexual assault investigations in the United Kingdom

Sexual assault casework requires the collaboration of multiple agency staff to formalise an investigative pipeline running from crime scene to court. While the same could be said of many other forensic investigations, few require the additional support of health care staff and the combined forensic involvement of body-fluid examiners, DNA experts and analytical chemists. The sheer amount of collaborative effort between agencies is laid out through a detailed examination of the investigative workflow from crime scene to courtroom with each step in the pipelines detailed and discussed. Beginning with a review of sexual assault legislation in the United Kingdom this article details how sexual assault investigations are initiated by police and supported by sexual assault referral centre (SARC) staff who are often the first responders providing primary healthcare and patient support to victims while simultaneously collecting and assessing forensic evidence. Detailing the myriad of evidential material that can be documented and collected at the SARC, the review identifies and categorises key forensic tests to first detect and identify body-fluids recovered from evidence through to the secondary analysis of DNA to help identify the suspect. This review also focusses on the collection and analysis of biological material used to support the allegation that the sexual activity was non-consensual and provides a breakdown of common marks and trauma as well as a review of common analytical methods used to infer Drug Facilitated Sexual Assault (DFSA). The culmination of the investigative pipeline is discussed by reviewing the Rape and Serious Sexual Assault (RASSO) workflow used by the Crown Prosecution Service before providing our thoughts on the future of forensic analysis and possible changes to the described workflows.

Sperm hunting on optical microscope slides for forensic analysis with deep convolutional networks - a feasibility study

Microscopic sperm detection is an important task in sexual assault cases. In some instances, the samples contain no or only low amounts of semen. Therefore, the biological material is transferred onto a glass slide and needs to be manually scanned using an optical microscope. This work can be very time consuming, especially when no spermatozoa is present. In such a case, the result needs to be validated. In this article we show how convolutional neural networks can perform this task and how they can reduce the scanning time by locating the sperm cells on images taken under the microscope. For this purpose, we trained a VGG19 network and a VGG19 variation with 1942 images, some containing sperm cells and some not.

Blood and sperm traces on human hair. A study on preservation and detection after 3-month outdoor exposure

Hair can retain important biological traces for forensic investigations. Forensic scientists are used to looking for such traces on clothing and skin of victims, however, when decomposition kicks in and all that remains of the victims is the skeleton, hair may be the only tissue representing the surface of the body at the time of a crime on which biological traces of an aggressor may have been left and still be detectable. Given the lack of research on this topic, this pilot study aims to assess the capacity of hair to retain semen and blood in hair, and the possibility to detect these fluids with well-known techniques and to obtain a useful genetic profile even when exposed to environmental conditions (Open Natural Environment (woods), Open Man Made Environment (urban)) for three months. Results showed that both traces were always visible and detectable with almost all techniques in the Control Environment, while in the two open environments some difficulties arose. However, biomolecular analysis was effective up to three months on both fluids in the Natural Environment and up to two months and one week respectively on blood and semen in the Man Made Environment. The Combur Test, OBTI, and Luminol were effective on blood up to three months in both environments while Sperm-HY-Liter and observation of cellular components were effective on semen up to at least 1 month and PSA testing was positive up to 1 week in both environments. The present work can be considered an encouraging starting point for the analysis of biological traces on hair in forensic contexts, regardless of the PMI, since blood and semen related to a crime may survive.

Generating aptamers towards human sperm cells using massively parallel sequencing

Determining the presence of sperm cells on an item or swab is often a crucial component of sexual offence investigation. However, traditional histological staining techniques used for the morphological identification of spermatozoa lack both specificity and sensitivity, making analysis a complex and time-consuming process. New methods for the detection of sperm cells based on aptamer recognition may be able to overcome these issues. In this work, we present the selection of ssDNA aptamers against human sperm cells using Cell-SELEX and massively parallel sequencing technologies. A total of 14 rounds of selection were performed following a modified Cell-SELEX protocol, which included additional steps for the isolation of spermatozoa from seminal fluid. Massively parallel sequencing using the Illumina Miseq platform was conducted on enriched aptamer pools to elucidate the structure of potential binders. A custom bioinformatics pipeline was also developed using Galaxy for the automated processing of sequencing datasets. This data revealed several promising aptamer candidates, which were shown to selectively bind sperm cells through both microscale thermophoresis and enzyme-linked oligonucleotide assays. These aptamers have the potential to increase the efficiency of sexual offence casework by facilitating sperm detection.

Current Methods for Body Fluid Identification Related to Sexual Crime: Focusing on Saliva, Semen, and Vaginal Fluid

Although, DNA typing plays a decisive role in the identification of persons from blood and body fluid stains in criminal investigations, clarifying the origin of extracted DNA has also been considered an essential task in proving a criminal act. This review introduces the importance of developing precise methods for body fluid identification. Body fluid identification has long relied on enzymatic methods as a presumptive assay and histological or serological methods as a confirmatory assay. However, because the latest DNA typing methods can rapidly obtain results from very small and even old, poorly preserved samples, the development of a novel corresponding body fluid identification method is required. In particular, an immunochromatographic method has been introduced to identify saliva and semen from sexual crimes. In addition, for vaginal fluid identification, attempts have been made in the past decade to introduce a method relying on body fluid-specific mRNA expression levels. At present, the development of molecular biological methods involving microRNA, DNA methylation, and resident bacterial DNA is ongoing. Therefore, in criminal investigations, body fluid identification is an essential task for correctly applying the results of DNA typing, although further research and development are required.

[Laser microdissection applications in histology: an open way to molecular studies]

One of the most fascinating aspects of the use of a laser beam in the field of biology has emerged with the development of devices able to perform fine dissections of biological tissues. Laser microdissection can collect phenotypically identical cells from tissue regions laid on a microscope slide in order to make differential molecular analyses on these microdissected cells. Laser microdissection can be used many areas including oncology to specify molecular mechanisms that enable to adapt a treatment related to diagnosis and research in biology, but also forensic science for tissue selection, neurology for post-mortem studies on patients with Alzheimer's disease, for clonality studies from cell cultures and cytogenetics to decipher chromosomal rearrangements. This technology represents the missing link between clinical observations and the intrinsic physiological mechanisms of biological tissues and its major applications will be addressed here.

Advanced forensic validation for human spermatozoa identification using SPERM HY-LITER™ Express with quantitative image analysis

Identification of human semen is indispensable for the investigation of sexual assaults. Fluorescence staining methods using commercial kits, such as the series of SPERM HY-LITER™ kits, have been useful to detect human sperm via strong fluorescence. These kits have been examined from various forensic aspects. However, because of a lack of evaluation methods, these studies did not provide objective, or quantitative, descriptions of the results nor clear criteria for the decisions reached. In addition, the variety of validations was considerably limited. In this study, we conducted more advanced validations of SPERM HY-LITER™ Express using our established image analysis method. Use of this method enabled objective and specific identification of fluorescent sperm's spots and quantitative comparisons of the sperm detection performance under complex experimental conditions. For body fluid mixtures, we examined interference with the fluorescence staining from other body fluid components. Effects of sample decomposition were simulated in high humidity and high temperature conditions. Semen with quite low sperm concentrations, such as azoospermia and oligospermia samples, represented the most challenging cases in application of the kit. Finally, the tolerance of the kit against various acidic and basic environments was analyzed. The validations herein provide useful information for the practical applications of the SPERM HY-LITER™ Express kit, which were previously unobtainable. Moreover, the versatility of our image analysis method toward various complex cases was demonstrated.

Veterinary Forensic Pathology of Animal Sexual Abuse

Animal sexual abuse (ASA) involves harm inflicted on animals for the purposes of human sexual gratification and includes such terms as bestiality, zoophilia, zoosadism, animal sexual assault, and others. The prevalence of ASA is not known, although it may be more common than is currently perceived. Veterinarians have the skills required to identify and document cases of ASA. This article reviews the terminology, legal definitions and forms of ASA, and its social and psychological context. An investigative approach is outlined, including an alternate light source examination; collection of swabs for DNA analysis; sampling vaginal washes, rectal washes, and toenails for trace evidence and biologic analyses; radiographic studies; and a complete forensic necropsy, including histopathology. Gross lesions identified in ASA victims include injuries to the anus, rectum, penis, scrotum, nipples, and vagina; the presence of foreign bodies; and abrasions, bruising, and other evidence of nonaccidental injury. Specialized procedures, including examination using alternate light sources and screening tests to identify human seminal fluid within samples from ASA victims, are of potential value but have not been validated for use in animals.

Development of a quantitative validation method for forensic investigation of human spermatozoa using a commercial fluorescence staining kit (SPERM HY-LITER™ Express)

In investigations of sexual assaults, as well as in identifying a suspect, the detection of human sperm is important. Recently, a kit for fluorescent staining of human spermatozoa, SPERM HY-LITER™, has become available. This kit allows for microscopic observation of the heads of human sperm using an antibody tagged with a fluorescent dye. This kit is specific to human sperm and provides easy detection by luminescence. However, criteria need to be established to objectively evaluate the fluorescent signals and to evaluate the staining efficiency of this kit. These criteria will be indispensable for investigation of forensic samples. In the present study, the SPERM HY-LITER™ Express kit, which is an improved version of SPERM HY-LITER™, was evaluated using an image analysis procedure using Laplacian and Gaussian methods. This method could be used to automatically select important regions of fluorescence produced by sperm. The fluorescence staining performance was evaluated and compared under various experimental conditions, such as for aged traces and in combination with other chemical staining methods. The morphological characteristics of human sperm were incorporated into the criteria for objective identification of sperm, based on quantified features of the fluorescent spots. Using the criteria, non-specific or insignificant fluorescent spots were excluded, and the specificity of the kit for human sperm was confirmed. The image analysis method and criteria established in this study are universal and could be applied under any experimental conditions. These criteria will increase the reliability of operator judgment in the analysis of human sperm samples in forensics.

SPERM HY-LITER™ for the identification of spermatozoa from sexual assault evidence

Accurate microscopic identification of human spermatozoa is important in sexual assault cases. We have compared the results of examinations with (1) a fluorescent microscopy method, SPERM HY-LITER™, and (2) Baecchi's method for identification of human spermatozoa. In 35 artificial, forensic type samples, spermatozoa were identified in 45.7% with SPERM HY-LITER™ in Copenhagen, in 54.3% in the laboratory of the manufacturer of SPERM HY-LITER™, and 40.0% of the samples with Baecchi's staining method. When differences occurred between the two methods, it was significantly more often that SPERM HY-LITER™ detected spermatozoa when Baecchi's method did not (ts=6.567, df=1, P=0.048). This trend was also seen in selected compromised or degraded samples and in selected adjudicative samples. The reactions with spermatozoa from dog, horse, pig and bull were negative with SPERM HY-LITER™, whereas Baecchi's method was non-selective. Data from forensic casework samples in Copenhagen from two years (2008 and 2009) are presented. The samples from 2008 were investigated using Baecchi's method, while those from 2009 were investigated using SPERM HY-LITER™. The frequencies of positive results were similar between the two methods for the two years (27.9% and 32.1% respectively). Analysis of acid phosphatase (ACP) activity for the positive results obtained for these two years does not support the use of a negative ACP result as a prescreen for microscopic analysis for spermatozoa.