1,5-Anhydro-d-glucitol in vitreous humor and cerebrospinal fluid — A helpful tool for identification of diabetes and diabetic coma post mortem

An Efficient Electrochemical Biosensor to Determine 1,5-Anhydroglucitol with Persimmon-Tannin-Reduced Graphene Oxide-PtPd Nanocomposites

1,5-Anhydroglucitol (1,5-AG) is a sensitive biomarker for real-time detection of diabetes mellitus. In this study, an electrochemical biosensor to specifically detect 1,5-AG levels based on persimmon-tannin-reduced graphene oxide-PtPd nanocomposites (PT-rGO-PtPd NCs), which were modified onto the surface of a screen-printed carbon electrode (SPCE), was designed. The PT-rGO-PtPd NCs were prepared by using PT as the film-forming material and ascorbic acid as the reducing agent. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), and X-ray diffraction (XRD) spectroscopy analysis were used to characterise the newly synthesised materials. PT-rGO-PtPd NCs present a synergistic effect not only to increase the active surface area to bio-capture more targets, but also to exhibit electrocatalytic efficiency to catalyze the decomposition of hydrogen peroxide (H₂O₂). A sensitive layer is formed by pyranose oxidase (PROD) attached to the surface of PT-rGO-PtPd NC/SPCE. In the presence of 1,5-AG, PROD catalyzes the oxidization of 1,5-AG to generate 1,5-anhydrofuctose (1,5-AF) and H₂O₂ which can be decomposed into H₂O under the synergistic catalysis of PT-rGO-PtPd NCs. The redox reaction between PT and its oxidative product (quinones, PTox) can be enhanced simultaneously by PT-rGO-PtPd NCs, and the current signal was recorded by the differential pulse voltammetry (DPV) method. Under optimal conditions, our biosensor shows a wide range (0.1-2.0 mg/mL) for 1,5-AG detection with a detection limit of 30 μg/mL (S/N = 3). Moreover, our electrochemical biosensor exhibits acceptable applicability with recoveries from 99.80 to 106.80%. In summary, our study provides an electrochemical method for the determination of 1,5-AG with simple procedures, lower costs, good reproducibility, and acceptable stability.

Biodistribution of Insulin Following Massive Insulin Subcutaneous Injection

A man in his 30s injected insulin several times into his abdomen and was found dead several hours later. Micropathological findings showed alveolar injury with hemorrhaging and cerebral parietal lobe nerve cell edema. Biochemical examinations showed that the blood insulin level was high, significantly so at the insulin injection sites. The blood glucose and C-peptide levels were low. The insulin level in the kidneys was low. In forensic medicine, a postmortem diagnosis of insulin subcutaneous injection is often difficult. When insulin injection is suspected, particularly high insulin levels can be expected at the insulin injection site, rather than in the blood.

Markers of hyperglycemia in the vitreous humor. A systematic review and meta-analysis

BACKGROUND

Vitreous humor has been extensively used in forensic practice to assess hyperglycemia after death. The results from different articles, for various hyperglycemia markers are highly variable, and a systematic analysis of the results from studies currently used in forensic practice as landmarks has not yet been performed. Therefore, we aimed to evaluate to usefulness and limits of using the values of vitreous glucose, lactic acid, beta-hydroxybutyrate, and 1,5 Anhydro-d-glucitol to detect postmortem hyperglycemia.

MATERIALS AND METHODS

For this purpose, we performed a systematic review and a meta-analysis using the random-effects model to identify the threshold values and average differences for the markers mentioned above in the vitreous humor of diabetic versus nondiabetic subjects.

RESULTS

We included eleven studies in the meta-analysis and found the following mean differences between the diabetic and nondiabetic groups: for glucose - 91.4 mg/dl, for lactate - 34.17 mg/dl, for the Traub formula - 111 mg/dl, for fructosamine - 0.71 mmol/L, for beta-hydroxybutyrate - 36.55 mg/dl and 1,5 Anhydro-d-glucitol - -15.2 mg/dl. We also gave practical recommendations, based on the range of values and 95% confidence intervals in normal subjects and controls to identify antemortem hyperglycemia and evaluated, whenever possible, threshold values for fatal diabetes.

CONCLUSIONS

Glucose, Traub formula, fructosamine, and beta-hydroxy-butyrate can be used to detect postmortem hyperglycemia with some limitations; 1,5 Anhydro-d-glucitol can only be used to suggest the absence of a hyperglycemic status before death.

Postmortem Determination of Short-Term Markers of Hyperglycemia for the Purposes of Medicolegal Opinions

Diabetes mellitus is classified as the epidemic of the 21st century. Due to the fact that acute carbohydrate metabolism disorders usually do not indicate morphological change, postmortem diagnosis is required to perform biochemical tests. The authors decided to evaluate the usefulness of determining glucose, lactate, acetone, β-hydroxybutyric acid (BHB), and 1,5-anhydroglucitol (1,5-AG) in postmortem blood/serum, urine, and vitreous humor (VH). Biological material was collected during autopsies. The study group consisted of 50 diabetics, while the control group consisted of 50 non-diabetics, who died a sudden death, with negative test results for the presence of ethyl alcohol and were not resuscitated before death. Statistical analysis was performed using the IBM SPSS Statistics 25 software package. The most statistically significant difference between the two groups was observed for mean 1,5-AG concentration. The authors found many correlations between the concentration of the examined markers in different materials, mainly between blood/serum and VH. The most suitable short-term glycemic marker in postmortem diagnosis is 1,5-AG. Diagnosis may be supported with determinations of acetone and BHB. For medicolegal assessment, the interpretation of the biochemical test results should comprise information on circumstances of death, medical history, results of other toxicological and histopathological tests, and autopsy report.

Vitreous humor endogenous compounds analysis for post-mortem forensic investigation

The chemical and biochemical analysis of bodily fluids after death is an important thanatochemical approach to assess the cause and time since death. Vitreous humor (VH) has been used as a biofluid for forensic purposes since the 1960s. Due to its established relevance in toxicology, a literature review highlighting the use of VH with an emphasis on endogenous compounds has not yet been undertaken. VH is a chemically complex aqueous solution of carbohydrates, proteins, electrolytes and other small molecules present in living organisms; this biofluid is useful tool for its isolated environment, preserved from bacterial contamination, decomposition, autolysis, and metabolic reactions. The post-mortem analysis of VH provides an important tool for the estimation of the post-mortem interval (PMI), which can be helpful in determining the cause of death. Consequently, the present review evaluates the recent chemical and biochemical advances with particular importance on the endogenous compounds present at the time of death and their modification over time, which are valuable for the PMI prediction and to identify the cause of death.