Forensics

  • Forensic Sperm Detection
  • Forensic Histopathology

Forensic scientists are tasked with the collection, preservation, and analysis of scientific evidence during the course of a criminal investigation. Within the field of forensic sciences, detection of semen is the primary method to confirm sexual assault. Other evidence, such as tissue samples, are used to examine the nature of incidents that may be linked to a particular crime.

Forensic Sperm Detection

Separation of sperm cells from the victim's DNA is crucial in identifying and characterizing the perpetrator's DNA profile. New methods to separate spermatozoa from other cells (e.g., with a laser microdissection system, such as the PALM MicroBeam system from Carl Zeiss) increase the efficiency of the method. However, in forensic samples, the overall number of spermatozoa can be very low, and usually accompanies a very inhomogeneous background of debris and other cells. Thus, traditional visual methods to detect sperm often cause case backlogs and longer time to result.

The automation of sperm detection is the most efficient method to solve sexual assault crimes. With Neon Metafer1, sperm cells in forensic samples are automatically detected and their positions on the slides are stored. Object coordinates can be quickly transferred to a microdissection system for further analysis.

Currently, the most reliable confirmation of positive visual identification of semen is with the Christmas Tree staining method. Two main reagents are used consecutively to produce this distinctive stain: Picroindigocarmine stains the neck and tail portions of the sperm in green and blue, while Nuclear Fast Red (also known as Kernechtrot) gives the sperm heads a red color and the tips of the heads (an area known as acrosomal cap) a pink color. Neon Metafer1 finds objects displaying this staining pattern, generating gallery images, and automatically sorting by quality.

Automated rare event detection is also available for various other protocols including dedicated fluorescence markers. Detected objects are fully documented as gallery images and cells are linked to their respective position on the sample. Adaptable ranking data allow for fast selection of cell subgroups. Results may be easily inspected on screen, or at the microscope, and unwanted objects are rejected with a simple mouse click.

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Forensic Histopathology

Forensic histology, or histopathology, applies histological techniques to the forensic pathology practice. This is very useful in the case of sudden death where trauma or poisoning must be ruled out. Microscopic examination of human tissue may yield valuable information about the nature and the extent of an injury present in an individual, that may be related to the cause of death. Findings may be quite significant as the examiner will often pass this information on to those responsible for the criminal investigation. Thorough documentation becomes a critical component for any successful criminal investigation.

The Metafer1 automated slide scanning system is an extremely versatile imaging platform providing a multitude of features for any application. Samples of various origins may be fully digitized and used as the basis for interpretation. Once digitized, degradation of the sample is no longer a problem. Furthermore, the collaborative image review and diagnosis development, among multiple professionals and across multiple sites, is now easily accomplished.

Metafer1’s unparalleled flexibility provides exceptional comprehension of the target sample. Regular brightfield light microscopy may be easily combined with fluorescence, with phase contrast, and even polarized light microscopy. Images obtained with these different methods may be superimposed, and cross-evidence may be visualized. Once elaborated, any investigation protocol is now highly reproducible; this aids in the reduction of review subjectivity and progression towards more robust QC/QA conditions.

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1 MetaSystems products are used in many countries worldwide. Depending on the regulations of the respective country or region, some products may not be used for clinical diagnostic use. In Europe MetaSystems products are CE labelled in-vitro diagnostics (IVD) devices. In the USA all MetaSystems products except the Ikaros karyotyping systems are intended to be used for research or inspection only.

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