Precision touch DNA sampling on plastic bag knots for improved profiling of packer and holder contributions

In forensic DNA analysis, evidence sampling stands as a pivotal step setting the ground for the quality of the forensic profiling. The collection of touch DNA from objects, when guidelines are scarce or absent, is usually governed by ad hoc decisions based on the available case circumstances. In our laboratory, in the context of illicit drug-related crimes, similar objects are frequently encountered, offering an opportunity for the standardization of evidence treatment. This study aims to develop an effective method for sampling touch DNA from knots on plastic bags. We examine both the exposed and hidden areas of knots, considering the latter as "protected" zones less likely to accumulate biological material during subsequent handling. The study contrasts a single sample method (whole knot surface sampling, Method 1) with dual-sample methods that separate exterior (exposed) and interior (hidden) surfaces of the knot. Notably, our study consistently reveals higher DNA yields from exterior surfaces of the knots as opposed to interior samples. Importantly, our findings demonstrate that utilizing a single sample may produce DNA profiles that are not interpretable, while employing a dual-sample approach may allow for the differentiation between the genetic contributions of the person who tied the knot, the packer, from the person who held the package, the holder. We have refined the dual-sample method to reduce holder DNA in the interior sample while maintaining it on the exterior, also allowing the packer's DNA to be detected on both surfaces. We explore four dual-sample collection methods. Method 2 involves taking the first sample from the exterior and the second from the interior of an untied knot. Method 3 visually differentiates between the original exposed and hidden surfaces for precise sampling. Method 4 employs tools to open the knot for interior sampling. Method 5 uses Diamond dye to highlight cell-free DNA on both surfaces before sampling. In conclusion, this study not only clarifies the complex dynamics of touch DNA transfer and collection on plastic bag knots, but also offers insights into standardizing evidence collection in similar cases.

Development of QSAR model based on Monte Carlo optimization for predicting GABAA receptor binding of newly emerging benzodiazepines

Benzodiazepines and their derivatives belong to a category of new psychoactive substances that have been introduced into the continually expanding illicit market. However, there is a notable absence of available pharmacological data for these substances. To gain a deeper understanding of their pharmacology, we employed the Monte Carlo optimization conformation-independent method as a tool for developing QSAR models. These models were built using optimal molecular descriptors derived from both SMILES notation and molecular graph representations. The resulting QSAR model demonstrated robustness and a high degree of predictability, proving to be very reliable. Moreover, we were able to identify specific molecular fragments that exerted both positive and negative effects on binding activity. This discovery paves the way for the swift prediction of binding activity for emerging benzodiazepines, offering a faster and more cost-effective alternative to traditional in vitro/in vivo analyses.

Hypoplastic arteries of the cerebral arterial ring in the blind spot of computed tomography angiography

BACKGROUND

Some variations of the cerebral arterial circle (CAC) are associated with an increased risk for the development of various pathological conditions. This paper aimed to determine the prevalence of hypoplastic arteries of CAC and to emphasize the limited possibility of their visualization by computed tomography angiography (CTA).

MATERIALS AND METHODS

The research was performed on 400 adult cadavers by macro- and microdissection of the cerebral arteries. Each case was photographed and the diameter of the arteries was measured digitally, by analyzing photographs of the bases of the brain in the ImageJ program.

RESULTS

The largest prevalence of artery diameter <1mm (<0.6mm) in CAC had the posterior communicating artery (PCoA). PCoA on the left side was hypoplastic in 44.9% (11.4%) of cases, while the same artery on the right side was hypoplastic in 44.3% (6.6%) of cases. The posterior cerebral artery was hypoplastic on the left side in 3% (0.6%) and on the right side in 4.2% (0.6%) of cases. The anterior cerebral artery had a hypoplastic caliber only on the right side in 2.4% (0.6%) of the cases, while the internal carotid arteries did not have a diameter <1mm in any case. The anterior communicating artery showed the greatest variability in morphology. Studies on CTA describe the occurrence of aplasia in a statistically significantly higher percentage, and the occurrence of hypoplastic arteries in a statistically significantly lower percentage compared to studies on cadavers.

CONCLUSIONS

Due to significant differences between cadaveric and radiological studies, it is necessary to analyze their results regarding arterial hypoplasia and aplasia separately. A diameter of less than 1 mm has been suggested as a criterion for arterial hypoplasia.

Morphometric analysis of the epineurial and endoneurial blood vessels of the human sciatic nerve in relation to aging

The aim of this research is to perform an analysis of the epineurial and endoneurial blood vessels in relation to aging. The research is conducted on samples of the human sciatic nerve of 12 case (age from 27 to 89). The histological sections are stained by streptavidin-biotin method of detecting the presence of Type IV collagen. After morphometric analysis the following stereological parameters have been calculated: the number of blood vessels per unit of area, the volume density of the blood vessels and the surface density of the blood vessels of the epineurium and endoneurium. An additional diameter measurement is performed for the endoneural blood vessels. In order to perform a more detailed analysis, the cases were classified into three age groups, the first (27-48 years), the second (49-70 years) and, the third (over 70 years). The bivariate correlation analysis showed that the number of blood vessels of the endoneurium, their volume and surface densities in relation to age produced a statistically significant positive correlation. One Way ANOVA test demonstrated a statistically significant increase in the number of endoneurial blood vessels in the age group III when compared the age group I and, in addition, it showed a significant decrease in the diameter of the age group II when compared to the age group I. Paired t - test shows a statistically significant higher number of endoneurial blood vessels in relation to the epineurial, namely, in the age group III. The volume and surface density of the epineurial blood vessels is significantly higher than the endoneurial in both the I and II age group. Age brings about significant changes of the endoneurial vascular network of the sciatic nerve due to the increase in density of the endoneurial blood vessels, their volume and surface densities. Consequently, in the cases older than 70 years, the number of endoneurial blood vessels significantly exceeds the number of epineurial blood vessels.

Unusual suicide with a chainsaw

A 39-year-old male, with a history of multiple suicidal attempts and psychiatric pathology, a professional lumberjack, was found dead at the meadow with his throat cut and a chainsaw beside him. Autopsy revealed that all physical injuries were confined to the head, neck and left shoulder. Two major (long and wide) wounds were found and documented on both sides of the neck and head. A wound on the posterior and right lateral side of his neck and head was noted. Medical examiner noted an irregular rupture on the posterior-right side of the atlanto-occipital joint with impaired bone, but without any damage on the spinal cord. Another gaping cut was noted in the lower part on the left lateral side of his neck. Medical examiner noted that muscles of the left side of the neck, left common carotid artery, left internal jugular vein and left vagus nerve were completely cut off. The body of the C5 and C6 vertebra, with the spinal cord at that level, was completely cut. Also, there were multiple linear and striped parallel abrasions on the outer side of the left shoulder and one abrasion on the left lateral side of the neck. The conclusion of inquiries was "suicide by chainsaw".

An excess vessel in the posterior part of the human cerebral arterial circle (CAC): a case series

BACKGROUND

As a continuation of the previous findings in human fetuses, accidental finding of an accessory vascular component in the posterior part of CAC of human adult cadavers inspired the authors to present and compare its posterior part configuration.

CASE PRESENTATION

Examination was carried out on brains of 48 human adult cadavers, routinely dissected at the Institute of Forensic Medicine. The aberrant vessel in the posterior part of four CACs was discovered.Vascular components of the posterior segment of CAC or of the whole CAC were described and photographed. A comparison between fetal and adult cases was also presented.

CONCLUSIONS

Based on the fact that the age of the four presented cases ranged from 73 to 84 and based on the causes of their death, we concluded that the angioarchitecture of the posterior part of the CAC is a consequence of the embryonic or primitive arterial stabilization and interaction with normal adult vessels.