Evaluation of the efficiency of Isohelix™ and Rayon swabs for recovery of DNA from metal surfaces.

PURPOSE: We investigated the recovery and extraction efficiency of DNA from three metal surfaces (brass, copper, steel) relevant to forensic casework, and plastic (control) using two different swabbing systems; Rayon and Isohelix™ swabs, with sterile water and isopropyl alcohol respectively, as the wetting solutions. METHODS: Twenty nanograms of human genomic DNA were applied directly to Isohelix™ and Rayon swabs; and to the metal and plastic substrates. All substrates were left to dry for 24 h, followed by single wet swabbing and extraction with the DNA IQ™ System. DNA extracts were quantified using real time quantitative PCR assays with SYBR green chemistry. RESULTS: DNA was extracted from directly seeded Isohelix™ swabs with a high efficiency of 98%, indicating effective DNA-release from the swab into the extraction buffer. In contrast, only 58% of input DNA was recovered from seeded Rayon swabs, indicating higher DNA retention by these swabs. Isohelix™ swabs recovered 32 - 53% of DNA from metal surfaces, whilst the Rayon swabs recovered 11-29%. DNA recovery was lowest from copper and highest from brass. Interestingly, Rayon swabs appeared to collect more DNA from the plastic surface than Isohelix™ swabs, however, due to the lower release of DNA from Rayon swabs they returned less DNA overall following extraction than Isohelix™ swabs. CONCLUSION: These results demonstrate that DNA samples deposited on metal surfaces can be more efficiently recovered using Isohelix™ swabs wetted with isopropyl alcohol than Rayon swabs wetted with sterile water, although recovery is affected by the substrate type.

Comparison of Isohelix™ and Rayon swabbing systems for touch DNA recovery from metal surfaces.

A previous study evaluating two swabbing systems found that DNA was best recovered from sterile metal substrates using an Isohelix™ swab wetted with isopropyl alcohol rather than a Rayon swab with water as the wetting agent. We tested the same swabbing systems on metal (aluminum, brass, and stainless steel) and plastic substrates in a regularly touched environment to simulate the non-deliberate transfer of touch evidence likely seen in a casework scenario, to ascertain the performance of these swabs in an uncontrolled situation. Higher amounts of touch DNA were recovered with Isohelix™ swabs (0.5 - 3.3 ng) compared to Rayon swabs (0.13 - 1.2 ng). The Isohelix™ swabbing system was found to significantly recover more touch DNA (p = 0.04) from the metal substrates than the Rayon swabbing system, consistent with the findings of our previous work. The results contribute to our understanding of the impact of sample collection techniques on touch DNA recovery from problematic metal surfaces and suggest that supplemental cleaning of substrates as a precautionary step against the spread of infections may affect touch DNA persistence and the recovery efficiency of swabs.

Ethics reporting in forensic science research publications - A review.

An essential element of compliance with ethical standards in scientific research is the reporting of a verifiable declaration of ethical approval and, when human subjects are involved - informed consent, in published works. The level of reporting of ethical permission for research published in forensic and investigative sciences journals has not been explored to date. Hence, we examined the reporting of ethical approval and informed consent in original research utilising human or animal subjects published in six forensic science journals from 2010 to 2019. We identified 10,192 articles and retained 3010 that satisfied the inclusion criteria of utilising human (91.2%), or animal (7.0%) or both (1.8%) subjects or tissues in experiments. Just over a third (1079/3010) of all studies declared obtaining ethical approval, with 927 (85.9%) of those indicating the name of the ethical committee, but only 392 (36%) provided an approval code. Furthermore, while consent was said to have been sought in 527 (17.5%) of studies, only 155 of those reported that written informed consent was obtained, eleven stated oral (verbal) consent, while the remaining 357 studies (67.7%) did not report the process used to gain consent. Ethical approval reporting rates differed between different research types, availability of financial support and whether authors were affiliated to academia or industry. The results demonstrate a low level of declaration of ethical approval and informed consent in forensic science research and publication, requiring urgent rectification. We support the adoption of the model proposed by Forensic Science International: Genetics as baseline recommendations to facilitate consistent nomenclature, transparency, and standard of ethical reporting in forensic science.

Immunotherapy for acute myeloid leukemia (AML): a potent alternative therapy.

The standard therapy of AML for many years has been chemotherapy with or without stem transplantation. However, there has not been any tangible improvement in this treatment beyond induction through chemotherapy and consolidation with allogeneic stem cell transplantation or chemotherapy. Residual AML cells which later cause relapse mostly persist even after rigorous standard therapy. It is imperative therefore to find an alternative therapy that can take care of the residual AML cells. With a better understanding of how the immune system works to destroy tumor cells and inhibit their growth, another therapeutic option immunotherapy has emerged to address the difficulties associated with the standard therapy. Identification of leukemia-associated antigens (LAA) and the fact that T and NK cells can be activated to exert cytotoxicity on AML cells have further introduced diverse immunotherapeutic development strategies. This review discusses the merits of current immunotherapeutic strategies such as the use of antibodies, adoptive T cells and alloreactive NK cell, and vaccination as against the standard therapy of AML.