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Next-generation sequencing (NGS) technologies have expanded the spectrum of forensic DNA analysis by facilitating efficient and precise genotyping of a large number of genetic markers. Yet, challenges persist regarding complex sample processing and assurance of equal molar concentrations across pooled samples. Since optimal cluster density is crucial for sequencing performance, the determination of both quantity and quality is indispensable for library preparation. In this study, we investigated the application of the Agilent 2100 Bioanalyzer for library quality control, as studies for forensic approaches, particularly for highly degraded postmortem samples, are rare. Our analysis encompassed assessing total DNA concentrations, fluorescence unit (FU) values, and adapter dimer concentrations in purified DNA libraries derived from buccal swabs and tissue samples of decomposed corpses. The sensitivity study tested a serial dilution derived from buccal swabs and revealed a decrease in FU values and an increase in adapter dimers with declining DNA input concentrations. Deviations in total DNA concentrations and average peak heights between the Agilent 2100 Bioanalyzer runs indicated a lack of repeatability in data and presented challenges in accurate quantification, which was also observed in previous studies. Yet, the analysis of degraded samples from decomposed human remains has shown the ability to detect adapter dimer concentrations, which can be crucial for the quality of subsequent NGS library preparation and sequencing success. Therefore, the Agilent 2100 Bioanalyzer proves to be a valuable tool for NGS quality control., (© 2024 The Author(s). Journal of Forensic Sciences published by Wiley Periodicals LLC on behalf of American Academy of Forensic Sciences.)

Touch DNA has become increasingly important evidence in todays' forensic casework. However, due to its invisible nature and typically minute amounts of DNA, the collection of biological material from touched objects remains a particular challenge that underscores the importance of the best collection methods for maximum recovery efficiency. So far, swabs moistened with water are often utilized in forensic crime scene investigations for touch DNA sampling, even though an aqueous solution provokes osmosis, endangering the cell's integrity. The aim of the research presented here was to systematically determine whether DNA recovery from touched glass items can be significantly increased by varying swabbing solutions and volumes compared with water-moistened swabs and dry swabbing. A second objective was to investigate the possible effects of storage of swab solutions prior to genetic analysis on DNA yield and profile quality when stored for 3 and 12 months, as is often the case with crime scene samples. Overall, the results indicate that adapting volumes of the sampling solutions had no significant effect on DNA yield, while the detergent-based solutions performed better than water and dry removal, with the SDS reagent yielding statistically significant results. Further, stored samples showed an increase in degradation indices for all solutions tested, but no deterioration in DNA content and profile quality, allowing for unrestricted processing of touch DNA samples stored for at least 12 months. One further finding was a strong intraindividual change in DNA amounts observed over the 23 deposition days which may be related to the donor's menstrual cycle., (© 2023 The Authors. Journal of Forensic Sciences published by Wiley Periodicals LLC on behalf of American Academy of Forensic Sciences.)

Introduction: Long dialysis treatments are generally assumed to mitigate the ultrafiltration (UF) induced volume perturbation and to improve vascular refilling because of reduced UF rates and sufficient time for volume re-equilibration. The time course of vascular refilling was therefore examined during extended nocturnal dialysis., Methods: For each hour of dialysis, vascular refilling volume was calculated from the absolute blood volume changes and UF volume removed. Absolute blood volume was estimated by indicator dilution at the beginning of dialysis and then tracked with a relative blood volume monitor. The refilling fraction was defined as the ratio of refilling volume to UF volume., Findings: Ten stable chronic hemodialysis (HD) patients were studied during extended (7 h) nocturnal treatment sessions. Specific UF rate was 4.8 ± 1.8 ml/kg/h. In the 1 h, refilling volume amounted to only 23% of UF volume. Thereafter, refilling fraction steeply increased and reached maximum values in the 2, 3 and 4 h at about mean 90% (91.5%, 88.7%, and 91.1% respectively). From the 5 h on, refilling volume decreased (5 h 81.3%, 6 h 72.5%, 7 h 70.0% of UF volume). Cumulative refilling reached 73.6% of UF volume after 4 h of treatment time. This did not change during the further course of HD. Cumulative refilling volume showed a strong correlation (r = 0.94; p < 0.001) with UF volume. The ratio of blood volume to extracellular volume (R bex ) was 0.306 ± 0.029 before and slightly but significantly increased to 0.326 ± 0.030 after UF., Discussion: In spite of low-UF rates and extended treatment times, overall refilling fraction reached only 74% and was not different from the refilling fraction observed in regular HD. This value seems to represent a point where UF-induced volume perturbation is adequately compensated by physiologic control mechanisms., (© 2022 International Society for Hemodialysis.)

Introduction: The success of automatic feedback control systems to improve hemodynamic stability by preventing relative blood volume from dropping beyond a critical value during dialysis is limited. The aim of this study was to use one of these systems for control of absolute rather than relative blood volume to prevent volume-dependent morbid events., Methods: Dialysis was delivered by a machine providing feedback control of ultrafiltration rates, relative blood volume monitoring, and accurate bolus infusion of 240 mL of dialysate to measure absolute blood volume at the beginning of dialysis. Critical relative blood volume required by the control algorithm was calculated from absolute blood volume at the beginning and a critical absolute blood volume of 67 mL/kg., Findings: In 40 stable patients, ultrafiltration was guided by blood volume using the feedback algorithm of the integrated program. Blood volume was maintained in a narrow range above the prespecified minimal value of 67 mL/kg. At the end of dialysis, absolute blood volume ranged from 67.5 to 72.5 mL/kg (69.4 ± 1.3 mL/kg). No volume-dependent intradialytic morbid event occurred., Discussion: A feedback control system for relative blood volume-controlled ultrafiltration can be used for control of absolute blood volume. A prescribed target of absolute blood volume can be converted into relative blood volume, and this can subsequently be reached automatically with the integrated feedback system of the dialysis machine. Intradialytic morbid events could be considerably reduced. The whole procedure could be completely automated without altering the hardware of the dialysis device., (© 2020 International Society for Hemodialysis.)

Introduction: Adequate volume management removing excess volume and at the same time avoiding intradialytic morbid events (IME) remains a core problem in current hemodialysis (HD) therapy. Recently, we developed a feasible method to determine absolute blood volume (Vs, in mL/kg) in patients on HD. The aim of this study was to investigate the suitability of Vs measurements for volume management., Methods: Following a 4 week baseline phase to quantify the frequency of IME, volume status was determined in a single specified HD session during which Vs was measured using dialysate dilution, volume overload (Vo, L) was measured using bioimpedance spectroscopy, and the occurrence of IME was recorded. Target weight was then adjusted and the frequency of IME was recorded during 4 weeks of follow-up., Findings: Forty-five patients participated in this study. Twenty-two (49%) patients experienced 66 IME in 12% of HD treatments during baseline. In 15 (33%) patients who experienced IME during volume assessment both Vs (60.7 ± 4.0 vs. 73.7 ± 11.3 mL/kg, P < 0.001) and Vo (1.1 ± 0.9 vs. 2.5 ± 1.8 L, P < 0.01) were significantly lower than in stable patients, respectively. The sensitivity, specificity, and accuracy of the ≤65 mL/kg Vs threshold to predict IME was 87%, 100%, and 91%, respectively. Target weight was increased (+1.5 kg) or decreased (-5 kg) in 32 patients. The frequency of IME fell to 0.9% of all HD sessions in the following 4 weeks (P < 0.001)., Discussion: Adjustment of target weight based on information of Vs, Vo, and IME appears as a feasible approach to reduce the frequency of IME., (© 2017 International Society for Hemodialysis.)

Introduction Blood volume changes and vascular refilling during hemodialysis (HD) and ultrafiltration (UF) have been assumed to depend on volume overload (Vo ). It was the aim to study the magnitude of vascular refilling in stable HD patients with moderate volume expansion in everyday dialysis using novel technical approaches. Methods Patients were studied during routine dialysis and UF based on clinical dry weight assessment. Pre-dialysis Vo was independently measured by bioimpedance spectroscopy. Vascular refilling volume (Vref ) was calculated as: Vref  = Vuf  - ΔV, where ΔV is the absolute blood volume change determined by on-line dialysate dilution using a commercial on-line hemodiafiltration machine incorporating a relative blood volume monitor, and where Vuf is the prescribed UF volume. Findings Thirty patients (dry weight: 81.0 ± 17.8 kg) were studied. Pre-dialysis Vo was 2.46 ± 1.45 L. Vuf was 2.27 ± 0.71 L, specific UF rate was 6.45 ± 2.43 mL/kg/h, and since ΔV was 0.66 ± 0.31 L, Vref was determined as 1.61 ± 0.58 L, corresponding to a constant refilling fraction (Fref ) of 70.6 ± 10.6%. Vref strongly correlated with Vuf (r(2)  = 0.82) but was independent of Vo and other volumes. Fref was also independent of Vo and other volumes normalized for various measures of body size. Discussion While vascular refilling and Fref is independent of Vo in treatments with moderate UF requirements, intravascular volume depletion increases with increasing UF requirements. The relationship between blood volume and Vo needs to be more closely examined in further studies to optimize volume control in everyday dialysis., (© 2016 International Society for Hemodialysis.)

The reduction of blood volume below a critical threshold is assumed to trigger intradialytic morbid events (IME). Recently, we presented a simple method to determine the absolute blood volume during routine hemodialysis (HD) carried out without blood sampling and without injection of dyes or radiolabeled markers. Such information could be used to detect excessive volume reduction during HD and to prevent IME. Therefore, we performed a pilot study in IME-prone patients to identify the absolute blood volume at which they developed clinical symptoms. A volume of 240 mL of ultrapure dialysate was automatically infused into the extracorporeal circulation using the bolus function of a commercial online hemodiafiltration machine incorporating a blood volume monitor (BVM). The increase in relative blood volume (RBV) caused by the infusion was measured and used to determine the absolute blood volume at that time. The blood volume per kilogram body mass at the time of symptomatic IME was also determined. All IME-prone patients of a single-dialysis center were included in the study. Ten out of 12 patients became symptomatic at a specific blood volume between 65 and 56 mL/kg (mean 62 mL/kg) whereas RBV showed a wide scatter (82-97%). A specific blood volume of 65 mL/kg seems to represent the threshold for IME by this method. The technique could be completely automated without altering the hardware of the dialysis device. Present feedback systems for automated blood volume-controlled ultrafiltration could be adapted to maintain absolute blood volume above this critical volume to safely prevent volume-dependent IME., (© 2015 International Society for Hemodialysis.)