Simultaneous analysis of potassium and ammonium ions in the vitreous humour by capillary electrophoresis and their integrated use to infer the post mortem interval (PMI)

2020 ◽  
pp. 002580242093423 ◽  
Author(s):  
Covadonga Palacio ◽  
Rossella Gottardo ◽  
Vito Cirielli ◽  
Giacomo Musile ◽  
Yvane Agard ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Clinical Chemistry ◽  
The Body ◽  
Simultaneous Analysis ◽  
Vitreous Humour ◽  
Ammonium Concentration ◽  
Time Of Death ◽  
Post Mortem ◽  
Ammonium Ions ◽  
Post Mortem Interval

Post-mortem changes of ions in the body fluids have been proposed as an objective tool for inferring the time of death. In particular, the post-mortem increase of potassium concentrations in the vitreous humour has gained great attention in the literature. On the other hand, ammonium, another ion released in post-mortem processes, has received much less attention, potentially due to unresolved analytical issues using current clinical chemistry methods. This paper presents an application of a new analytical approach based on capillary electrophoresis providing the simultaneous analysis of potassium and ammonium ions in the vitreous humour. In addition, to assess the consistency of the post-mortem increase of ammonium concentrations in the vitreous humour, the determination of this ion in the vitreous humour of the two eyes of the same body at the same post-mortem interval has been verified. Vitreous humour was collected from 33 medico-legal cases where the time of death was known exactly. Prior to analysis, all samples were diluted 1:20 with a 40 μg/mL solution of BaCl2 (internal standard). In the study of the variability of the ammonium concentration between the two eyes, no statistically significant differences were found, supporting the hypothesis of an even post-mortem increase of the ion concentrations in this particular biological fluid. Significant correlations of potassium and ammonium ions with the post-mortem interval were found, with r2 of 0.75 and 0.70, respectively.

The Effect of the Post-Mortem Interval on the Level of Creatine in Vitreous Humour

1989 ◽  
Vol 29 (1) ◽  
pp. 47-54 ◽  
Author(s):  
M. Piette
Keyword(s):  
Confidence Interval ◽  
Vitreous Humour ◽  
Time Of Death ◽  
Post Mortem ◽  
Legal Practice ◽  
Post Mortem Interval ◽  
Satisfactory Correlation

By means of 103 medico-legal autopsies it was established that a rise in the creatine level occurs in the vitreous humour after death. In view of the satisfactory correlation between the post-mortem interval and the creatine level in the vitreous humour (r = 0.84, p < 0.001) investigations were undertaken as to whether the creatine level in vitreous humour can serve in current medico-legal practice as an indication for the post-mortem interval, especially for the later period (more than three days). On balance this creatine determination is only useful when combined with all other medico-legal parameters that establish the time of death, remembering that the confidence-interval in the investigations was rather wide.

Levels of Potassium in the Vitreous Humour after Death

1965 ◽  
Vol 5 (3) ◽  
pp. 150-156 ◽  
Author(s):  
Wilhelmina M. H. Hughes
Keyword(s):  
Potassium Level ◽  
Accurate Method ◽  
Vitreous Humour ◽  
Time Of Death ◽  
Post Mortem ◽  
Post Mortem Interval

Levels of vitreous potassium were studied in 135 routine post-mortem cases. A rise in the potassium level was found but it could not be correlated with sufficient consistency with the post-mortem interval to make this an accurate method of estimating the time of death.

A new method for the determination of ammonium in the vitreous humour based on capillary electrophoresis and its preliminary application in thanatochemistry

2019 ◽  
Vol 57 (4) ◽  
pp. 504-509 ◽  
Author(s):  
Rossella Gottardo ◽  
Covadonga Palacio ◽  
Kseniia M. Shestakova ◽  
Natalia E. Moskaleva ◽  
Federica Bortolotti ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Limit Of Detection ◽  
Forensic Analysis ◽  
Uv Detection ◽  
Vitreous Humour ◽  
Post Mortem ◽  
Indirect Uv Detection ◽  
Post Mortem Interval ◽  
Preliminary Application

Abstract Background Although the post-mortem increase of ammonium in biological fluids is well known, ammonium analysis in vitreous humour has never been used in recent times for the determination of the post-mortem interval. The present work represents a new application of capillary electrophoresis with indirect UV detection in the field of forensic analysis. Methods The electrophoretic separation was carried out in a running buffer made of 5 mM imidazole, 5 mM 18-crown-6 ether and 6 mM d,l-α-hydroxybutyric acid (HIBA). To overcome the lack of optical absorption of ammonium, indirect UV detection was applied. The used wavelength was 214 nm. Results The method showed good linearity in the concentration range from 0.16 to 5.0 mM. The limit of detection, 0.039 mmol/L, was established on the basis of the linearity curve. Precision and bias studies carried out on the pure ammonium solutions and in real biological samples, revealed %RSDs well below 20%. A preliminary application to real cases where the death time was precisely known (14 bodies) was carried out plotting vitreous humour ammonium vs. post-mortem interval with a resulting good linear correlation until 100 h post-mortem. Conclusions After validation in real cases, the present method can become a powerful tool to unravel one of the most challenging issues of forensic investigation: determination of the time of death.

A Review of the Literature as to the Present Possibilities and Limitations in Estimating the Time of Death

1976 ◽  
Vol 16 (4) ◽  
pp. 269-276 ◽  
Author(s):  
R. Van Den Oever
Keyword(s):  
Forensic Medicine ◽  
Large Error ◽  
Time Of Death ◽  
Post Mortem ◽  
Review Of The Literature ◽  
Biochemical Tests ◽  
Post Mortem Interval ◽  
Suitable Combination ◽  
Exact Moment ◽  
The Individual

Determining the exact moment of death in medicolegal cases is not possible since post-mortem changes of the human body are variable and often misjudged. The most reliable physical and biochemical methods of estimating the post-mortem interval are reviewed and the author tries to find out why, in spite of all the previous studies, which have often given good results, the individual methods are neither popular nor practical in routine forensic medicine cases. For greater accuracy in estimating the time of death further investigation should be carried out to find a suitable combination of some physical and biochemical tests complementary to the data produced by each method and preventing the rather large error range of each individual test.

Estimation of post-mortem interval: A comparison between cerebrospinal fluid and vitreous humour chemistry

2015 ◽  
Vol 36 ◽  
pp. 144-148 ◽  
Author(s):  
Rajanikanta Swain ◽  
Adarsh Kumar ◽  
Jyotiranjan Sahoo ◽  
R. Lakshmy ◽  
S.K. Gupta ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Vitreous Humour ◽  
Post Mortem ◽  
Post Mortem Interval

Vitreous humour as a complementary sample to blood for the detection/confirmation of diazepam: ante-mortem and post-mortem studies in an animal model

2004 ◽  
Vol 23 (12) ◽  
pp. 571-577 ◽  
Author(s):  
H M Teixeira ◽  
F Reis ◽  
P Proença ◽  
P Ramos ◽  
O Quińtela ◽  
...  
Keyword(s):  
Drug Administration ◽  
Plasma Concentrations ◽  
Forensic Toxicology ◽  
Vitreous Humour ◽  
Toxic Substances ◽  
Time Of Death ◽  
Post Mortem ◽  
Correlation Ratio ◽  
Animal Group ◽  
Toxic Dose

The quantification of medical or toxic substances in vitreous humour (VH) could be very useful in forensic toxicology when blood sample determinations are impossible due to absence or deterioration. However, few studies have been made in this area and even fewer have tried to find a relationship between drug levels in both samples. To determine a correlation ratio between blood and VH diazepam (DZ) levels, we performed an experimental study using rabbits administered with a sub-toxic dose of DZ under known and controlled conditions. Blood and VH samples were collected 0.5, 1, 2, 3 and 6 hours after the drug administration in order to determine DZ and its main active metabolite, desmethyldiazepam (DMD). In addition, we have studied an animal group sacrificed 2 hours after intramuscular (i.m.) drug administration with blood and VH collection 24 hours later, to evaluate the existence of possible post-mortem changes. After DZ administration, a fast absorption phase was observed with a plasma Cmax value 1 hour after, followed by a rapid concentration decrease, with a half-life of 1 hour, indicating that, besides elimination, a fast distribution to other organs and tissues and/or hepatic metabolism occurred. Diazepam Cmax value in VH was achieved between 1 and 2 hours, when plasma concentrations had already decreased to half the value. The plasma/VH DZ ratio calculated at this time was 10. In the post-mortem study, while plasma DZ concentration at 24 hours was smaller, DMD levels were higher than those at the time of death. In the VH, both DZ and DMD concentrations at 24 hours were higher than those obtained at the time of death. That is, in both fluids DZ and DMD concentrations were different from those at the time of death and post-mortem distribution and redistribution phenomena occurred. The combination of antemortem and post-mortem studies has allowed the determination of a correlation ratio for DZ in the rabbit of 6×, comparing the concentrations in VH collected 24 hours after death with the concentrations detected in plasma at the time of death. This study opens new perspectives for the use of VH as a complementary sample to blood for DZ detection and confirmation. The putative relevance of the correlation ratio obtained, for forensic toxicology practice with medical substances, namely benzodiazepines, recommends further studies in humans.

scholarly journals Dysregulation of miR-381-3p and miR-23b-3p in skeletal muscle could be a possible estimator of early post-mortem interval in rats

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11102
Author(s):  
Vanessa Martínez-Rivera ◽  
Christian A. Cárdenas-Monroy ◽  
Oliver Millan-Catalan ◽  
Jessica González-Corona ◽  
N. Sofia Huerta-Pacheco ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
In Silico Analysis ◽  
Forensic Analysis ◽  
The Body ◽  
Control Group ◽  
Post Mortem ◽  
Rt Pcr ◽  
Post Mortem Interval ◽  
Silico Analysis

Background The post-mortem interval (PMI) is the time elapsed since the dead of an individual until the body is found, which is relevant for forensic purposes. The miRNAs regulate the expression of some genes; and due to their small size, they can better support degradation, which makes them suitable for forensic analysis. In the present work, we evaluated the gene expression of miR-381-3p, miR-23b-3p, and miR-144-3p in skeletal muscle in a murine model at the early PMI. Methods We designed a rat model to evaluate the early PMI under controlled conditions. This model consisted in 25 rats divided into five groups of rats, that correspond to the 0, 3, 6, 12 and 24 hours of PMI. The 0 h-PMI was considered as the control group. Muscle samples were taken from each rat to analyze the expression of miR-381-3p, miR-23b-3p, and miR-144-3p by quantitative RT-PCR. The gene expression of each miRNA was expressed as Fold Change (FC) and compared among groups. To find the targets of these miRNAs and the pathways where they participate, we performed an in-silico analysis. From the gene targets of miR-381-3p identified in the silico analysis, the EPC1 gene was selected for gene expression analysis by quantitative RT-PCR in these samples. Also, to evaluate if miR-381-3p could predict the early PMI, a mixed effects model was calculated using its gene expression. Results An upregulation of miR-381-3p was found at 24 h-PMI compared with the control group of 0 h-PMI and (FC = 1.02 vs. FC = 1.96; p = 0.0079). This was the opposite for miR-23b-3p, which had a down-regulation at 24 h-PMI compared to 0 h-PMI (FC = 1.22 vs. FC = 0.13; p = 0.0079). Moreover, the gene expression of miR-381-3p increased throughout the first 24 h of PMI, contrary to miR-23b-3p. The targets of these two miRNAs, participate in biological pathways related to hypoxia, apoptosis, and RNA metabolism. The gene expression of EPC1 was found downregulated at 3 and 12 h of PMI, whereas it remained unchanged at 6 h and 24 h of PMI. Using a multivariate analysis, it was possible to predict the FC of miR-381-3p of all but 6 h-PMI analyzed PMIs. Discussion The present results suggest that miR-23b-3p and miR-381-3p participate at the early PMI, probably regulating the expression of some genes related to the autolysis process as EPC1 gene. Although the miR-381-3p gene expression is a potential estimator of PMI, further studies will be required to obtain better estimates.

scholarly journals Application of research in the field of forensic entomology for determining the time of death in dogs

2018 ◽  
Vol 74 (1) ◽  
pp. 33-38
Author(s):  
PIOTR LISTOS ◽  
MAGDALENA GRYZIŃSKA ◽  
JUSTYNA BATKOWSKA ◽  
MAŁGORZATA DYLEWSKA ◽  
KATARZYNA CZEPIEL-MIL
Keyword(s):  
Forensic Entomology ◽  
Animal Experiments ◽  
The Body ◽  
Calliphora Vicina ◽  
Developmental Cycle ◽  
Time Of Death ◽  
Post Mortem ◽  
Main Experiment ◽  
Ambient Conditions

Precisely determined time of death is one of the most important pieces of information obtained during a post-mortem investigation. There are several traditional methods for determining time of death, the most important of which are evaluation of early post-mortem changes, such as the change in body temperature. The study was aimed at identifying insects collected from the body and establishing the time of death by observing the developmental cycle of the indicator species Calliphora vicina. The material for the main experiment was the carcass of a dog. The length of the developmental cycles of insects depends on ambient conditions, so studies should take as many criteria as possible into account. Succession of arthropods, as well as the species composition and indicator insects of particular stages of decomposition, is very similar in human and animal carcasses. The results obtained were considered with respect to the time that had passed since the death of the animal. Experiments on dog carcasses may in the future contribute to the development of research enabling determination of the time of death of animals, which is a subject of increasing interest in forensic veterinary medicine....

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