Insulin overdose with fatal outcome?: Two forensic cases

Intentional overdose with insulin preparations is rare. However, fatal consequences due to severe hypoglycemia could occur. Postmortem toxicology screening of insulin is a challenge, given the chemical characteristics of this protein and the difficulty of distinguishing between endogenous and exogenous insulin in blood. Here, we describe two cases of patients with diabetes using insulin and oral anti-diabetics. The main question in both cases was whether or not disturbance in glucose metabolism contributed to death. In case A, there was strong evidence that self-poisoning with insulin and subsequent hypoglycemia caused the death. However, this could not be confirmed due to lack of adequate forensic toxicology tests. In case B, no hypoglycemia was observed. Though, compared with case A, additional forensic examination was performed to investigate whether glycemic disturbances could have contributed to the death. In this report, we focus on the most appropriate analytical methods for the detection of exogenous insulin in the human body and give recommendations for toxicology testing of glucose levels and insulin in postmortem specimens.

A Biochemical and Histological Assessment of Postmortem Changes to the Eyes of Domestic Pigs: A Preliminary Study

The Postmortem Interval (PMI) is the time from the death of an animal to its discovery. From a veterinary forensic standpoint, an accurate estimation of the PMI is of particular importance, especially with the observed increase in deaths of domestic and wild animals. A preliminary study was conducted using the eyes of domestic pigs. A biochemical analysis was conducted on the vitreous humor of the eye, whilst a histological analysis was conducted on the retina. The eyes were stored at +4 °C and changes were assessed at time intervals of 0, 12, 24, 48, and 120 h. The biochemical analysis during the PMI established a decrease in sodium, chlorine, and glucose concentrations, and a rise in potassium concentration. Accordingly, a simple linear regression showed a significant correlation between changes in concentrations of sodium (Na+), potassium (K+), chloride (Cl-), and glucose, in relation to the PMI. The histological analysis showed evident morphological changes in the retina, which included homogenization of the rod and cone cells, pyknosis of the outer nuclear layer, homogenization of the outer plexiform layer, pyknosis of the inner nuclear layer, homogenization of the inner plexiform layer, and pyknosis of the nuclei of the ganglion layer of the retina.

Establishing vitreous glucose and beta-hydroxybutyrate thresholds to assist in the diagnosis of hypothermia

The post-mortem diagnosis of hypothermia is challenging to establish due to the lack of pathognomonic findings and the confounding problem that any comorbidity may account for death. A 4-year retrospective case-control study was performed to compare the vitreous glucose and beta-hydroxybutyrate (BHB) concentrations between hypothermia deaths and controls. Over the study period 34 cases of hypothermia and 39 controls were analyzed. Hypothermia deaths versus controls had higher mean vitreous glucose (2.93 mmol/L vs. 1.14 mmol/L; p < 0.0001), BHB (1.89 mmol/L vs. 1.35 mmol/L; p = 0.01), and combined glucose+BHB (4.83 mmol/L vs. 2.46 mmol/L; p < 0.0001). Receiver operating characteristic (ROC) curves showed that the best model for predicting hypothermia in all cases was a combined vitreous glucose+BHB threshold of 2.03 mmol/L (sensitivity 88.2 %; specificity 56.4 %). A sub-group analysis broken down by detectable levels of blood ethanol showed that cases of hypothermia with and without ethanol maintained higher median vitreous glucose relative to the controls (2.05 vs. 0.35 mmol/L and 2.70 vs. 0.65 mmol/L; p = 0.02), however median BHB was only significantly elevated when ethanol was absent (1.88 vs. 1.42 mmol/L; p < 0.0001). Subsequent ROC curve analysis demonstrated that a better model for predicting hypothermia was in cases when blood ethanol was absent. In those deaths vitreous BHB alone had the best area under the curve, with an optimum threshold of 1.83 mmol/L (sensitivity 83.3 %; specificity 96.3 %). This study shows that post-mortem vitreous glucose and BHB are useful ancillary studies to assist in the diagnosis of hypothermia. Ethanol however is a confounder and can alter the utility of vitreous BHB when diagnosing hypothermia in those who have consumed alcohol prior to death.

Detection of Fatal Potassium Overdose: A Case Report and Review of the Literature

Potassium overdose usually occurs accidentally, but potassium is also used for judicial executions, assisted death, and, rarely, suicides. In addition to exogenous overdose, various drugs, and renal failure, diabetic ketoacidosis can cause hyperkalemia. Potassium tablets are used in most cases of suicidal potassium overdose. Suicide by intravenous administration of potassium is rare but usually fatal. The author reports a rare case of suicide with potassium infusion. Autopsy and histology findings, along with post-mortem biochemical analysis of different body fluids and fluid from the infusion set, are reported. Previously published reports of potassium overdose were reviewed, and the detection possibilities of potassium overdose are discussed. The detection possibilities of lethal hyperkalemia are very limited since hyperkalemia produces only nonspecific autopsy and histology findings. Post-mortem potassium concentrations are not indicative of ante-mortem potassium concentrations; therefore, post-mortem biochemical analysis has limited value in determining potassium overdose. The best way to prove potassium overdose is via the collection and analysis of circumstantial evidence.

In Vitro Animal Model for Estimating the Time since Death with Attention to Early Postmortem Stage

Estimating the postmortem interval (PMI) has remained the subject of investigations in forensic medicine for many years. Every kind of death results in changes in metabolites in body tissues and fluids due to lack of oxygen, altered circulation, enzymatic reactions, cellular degradation, and cessation of anabolic production of metabolites. Metabolic changes may provide markers determining the time since death, which is challenging in current analytical and observation-based methods. The study includes metabolomics analysis of blood with the use of an animal model to determine the biochemical changes following death. LC-MS is used to fingerprint postmortem porcine blood. Metabolites, significantly changing in blood after death, are selected and identified using univariate statistics. Fifty-one significant metabolites are found to help estimate the time since death in the early postmortem stage. Hypoxanthine, lactic acid, histidine, and lysophosphatidic acids are found as the most promising markers in estimating an early postmortem stage. Selected lysophosphatidylcholines are also found as significantly increased in blood with postmortal time, but their practical utility as PMI indicators can be limited due to a relatively low increasing rate. The findings demonstrate the great potential of LC-MS-based metabolomics in determining the PMI due to sudden death and provide an experimental basis for applying this attitude in investigating various mechanisms of death. As we assume, our study is also one of the first in which the porcine animal model is used to establish PMI metabolomics biomarkers.

HbA1c and biomarkers of diabetes mellitus in Clinical Chemistry and Laboratory Medicine: ten years after

Since its discovery in the late 1960s, HbA_1c has proven to be a major biomarker of diabetes mellitus survey and diagnosis. Other biomarkers have also been described using classical laboratory methods or more innovative, non-invasive ones. All biomarkers of diabetes, including the historical glucose assay, have well-controlled strengths and limitations, determining their indications in clinical use. They all request high quality preanalytical and analytical methodologies, necessitating a strict evaluation of their performances by external quality control assessment trials. Specific requirements are needed for point-of-care testing technologies. This general overview, which describes how old and new tools of diabetes mellitus biological survey have evolved over the last decade, has been built through the prism of papers published in Clinical Chemistry and Laboratory Medicine during this period.

Usefulness of a blood glucose and ketone monitoring device as a screening tool for lethal diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a frequent and life-threatening complication, whose diagnosis remains challenging in forensic practice. We aimed at assessing the performance of a commercially available blood glucose and ketone monitoring device (BGMD) in measuring glucose and ketone levels in post-mortem vitreous (VH) and blood samples, in order to determine if such a device can be used for screening lethal cases of DKA at autopsy. VH and blood samples were collected in cases of unexplained causes of death at autopsy. Glucose and β-hydroxybutyrate (BHB) were measured in VH and BHB in blood using the BGMD. The values were compared to those obtained with validated enzymatic methods. Values ≥ 10 mmol/L were considered to be elevated for glucose, and BHB values ≥ 2.5 mmol/L were considered to indicate ketoacidosis. There was a strong and significant correlation between VH glucose and blood BHB concentrations measured with the BGMD and the validated method (r = 0.78 and r = 0.80, p < 0.0001, respectively), whereas no correlation was found for VH BHB values (r = 0.19, p = 0.19). The sensitivity and specificity of the BGMD were both excellent (1.0) to detect elevated VH glucose levels with a threshold of 14.4 mmol/L, and to detect elevated blood BHB levels with a threshold of 2.85 mmol/L. In contrast, the specificity of the BGMD to detect high BHB levels in VH was poor (0.50) with an optimal threshold of 2.5 mmol/L. We showed that a commercially available BGMD is suitable for identifying cases of lethal DKA and other metabolic disorders at autopsy, through the investigation of vitreous glucose and blood BHB. We therefore recommend the systematic use of a BGMD for screening these conditions in cases of unexplained deaths.

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.

Lactate determination in human vitreous humour by capillary electrophoresis and time of death investigation

Forensic inquests, particularly, in assessing time since death currently recognize the importance of the analysis of vitreous humour (VH) biomarkers. Present research, studies, and validates the determination of lactate (La) in VH by CZE with indirect UV detection. The BGE (pH 8.9) consisted of Tris buffer (37 mM) containing 4-methoxybenzoic acid (4 mM) and alkyl-trimethyl-ammonium bromide (1.2 mM). Each VH specimen was diluted with a butyric acid solution (internal standard 0.057 mM) and La and butyrate were separated within 3-5 min (30 kV). The La LOQ and LOD were 4 and 2 mM, respectively. The calibration curve linearity ranged from 4 to 80 mM; intra- and interruns precisions were less than 10% for standard as well as for VH specimen, respectively. To investigate postmortem interval (PMI) and VH lactate level correlation, human VH specimens were collected during autopsy (n = 40) and stored at -20°C until assay. La levels ranged from 16 to 42 mM; PMI values ranged from 10 to 141 h. La (mM) and PMI (h) correlation was statistically significant (r² = 0.527; p < 0.05). In conclusion, the present CZE analysis is efficacious to determine VH La as a biomarker for PMI investigation.

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.

Sudden death due to diabetic ketoacidosis following power failure of an insulin pump: Autopsy and pump data

PURPOSE

To report a case in which autopsy findings and data from an insulin pump illustrate the course up to the death of a 31-year-old man with a history of type 1 diabetes mellitus who was found dead in his apartment with his insulin pump disassembled and placed in another room.

METHODS

Autopsy findings including histological, toxicological and biochemical examination are presented. Postmortem download of data from the insulin pump gave the history of the pump, which included blood glucose, insulin bolus, carbohydrate intake and the time course in the days to death, and the pump settings were recorded. For this case report, police reports on the death as well as hospital records were also reviewed.

RESULTS

At the patch for the insulin pump, nothing abnormal was found. Biochemical analysis showed glucose of 35 mmoL/L in vitreous humor fluid indicating antemortem hyperglycemia, and ketone bodies in the blood of 11.0 mmoL/L indicating ketoacidosis. Acute pulmonary hemostasis, chronic fat accumulation in the liver and acute fat accumulation in the kidneys were histological detected. There were no signs of late diabetic complications such as nephropathy or cardiovascular disease in the tissues. Insulin pump data showed that after three alarms, a power failure of the pump occurred leading to discontinuing insulin delivery, and about 48 h before the deceased was found dead, his body was depleted of insulin.

CONCLUSION

The cause of death is believed to be diabetic ketoacidosis due to completely lack of insulin because of power failure of the insulin pump, which therefore has been a decisive factor in the cascade of events that led to death. The case is, to our knowledge, the first to illustrate a death caused by diabetic ketoacidosis which is supported by autopsy findings and by data of an insulin pump up to the time of power failure. It is a strong example of usefulness of postmortem download of data from insulin pumps to help determine the cause of death among diabetics. Forensic pathologists should therefore review data and history of the pump systematically.

Toxicological and Biochemical Analyses of an Autopsy Case Involving Oral Overdose of Multiple Antidiabetic and Antihypertensive Drugs

Oral antidiabetics can cause fatal hypoglycemia; although they can be chemically identified and quantified, biochemical investigations are important for assessing the biological consequences of an overdose. Such cases of overdose involving oral antidiabetics may involve other drugs for treating lifestyle-related diseases, particularly antihypertensives. Here, we report a toxicological and biochemical investigation of drugs and biochemical profiles in a fatal overdose involving multiple oral antidiabetics and antihypertensives. A 55-year-old woman died about 2 days after the ingestion of around 110 tablets of antidiabetics and antihypertensives that had been prescribed for her husband. A forensic autopsy and histological analysis demonstrated no evident pathology as the cause of death. A toxicological analysis suggested hypoglycemia and an overdose of antihypertensives as well as the retention of antidiabetics and diuretics in the pericardial fluid. A relatively low pericardial amlodipine concentration was observed, which may have been the result of its long half-life (slower distribution and reduction rate) and/or possible affinity with the myocardium. In addition, a biochemical analysis indicated hypoglycemia, without increased serum insulin and C-peptide, but with increased glucagon levels, as the possible influence of glibenclamide overdose. These observations suggest the usefulness of a combination of toxicological and biochemical analyses in postmortem investigations involving a fatal overdose of such drugs.

Metabolomics in the study of retinal health and disease

Metabolomics is the qualitative and quantitative assessment of the metabolites (small molecules < 1.5 kDa) in body fluids. The metabolites are the downstream of the genetic transcription and translation processes and also downstream of the interactions with environmental exposures; thus, they are thought to closely relate to the phenotype, especially for multifactorial diseases. In the last decade, metabolomics has been increasingly used to identify biomarkers in disease, and it is currently recognized as a very powerful tool with great potential for clinical translation. The metabolome and the associated pathways also help improve our understanding of the pathophysiology and mechanisms of disease. While there has been increasing interest and research in metabolomics of the eye, the application of metabolomics to retinal diseases has been limited, even though these are leading causes of blindness. In this manuscript, we perform a comprehensive summary of the tools and knowledge required to perform a metabolomics study, and we highlight essential statistical methods for rigorous study design and data analysis. We review available protocols, summarize the best approaches, and address the current unmet need for information on collection and processing of tissues and biofluids that can be used for metabolomics of retinal diseases. Additionally, we critically analyze recent work in this field, both in animal models and in human clinical disease, including diabetic retinopathy and age-related macular degeneration. Finally, we identify opportunities for future research applying metabolomics to improve our current assessment and understanding of mechanisms of vitreoretinal diseases, and to hence improve patient assessment and care.

NMR-based Metabolomic Techniques Identify the Toxicity of Emodin in HepG2 Cells

Emodin is a natural anthraquinone derivative that is present in various herbal preparations. The pharmacological effects of emodin include anticancer, hepatoprotective, anti-inflammatory, antioxidant and even antimicrobial activities. However, emodin also has been reported to induce hepatotoxicity, nephrotoxicity, genotoxicity and reproductive toxicity. The mechanism of emodin's adverse effects is complicated and currently not well understood. This study aimed to establish a cell metabonomic method to investigate the toxicity of emodin and explore its potential mechanism and relevant targets. In the present study, metabonomic profiles of cell extracts and cell culture media obtained using the ¹H NMR technique were used to assess emodin toxicity in HepG2 cells. Multivariate statistical analyses such as partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were used to characterize the metabolites that differed between the control and emodin groups. The results indicated that emodin resulted in differences in 33 metabolites, including acetate, arginine, aspartate, creatine, isoleucine, leucine and histidine in the cell extract samples and 23 metabolites, including alanine, formate, glutamate, succinate and isoleucine, in the cell culture media samples. Approximately 8 pathways associated with these metabolites were disrupted in the emodin groups. These results demonstrated the potential for using cell metabonomics approaches to clarify the toxicological effects of emodin, the underlying mechanisms and potential biomarkers. Our findings may help with the development of novel strategies to discover targets for drug toxicity, elucidate the changes in regulatory signal networks and explore its potential mechanism of action.

Point-of-care hemoglobin A1c testing in postmortem examination

Glycated hemoglobin (HbA1c) is a good marker for monitoring glycemic control, and an elevated postmortem blood HbA1c level might indicate poor glycemic control during the antemortem period. The HbA1c level can be measured as a point-of-care (POC) test. In forensic medicine, POC testing is useful for performing autopsies and postmortem inspections since POC testing is both rapid and efficient. This study evaluated HbA1c levels in the capillary and cardiac venous blood of postmortem specimens as well as the usefulness of evaluating HbA1c levels as POC testing in postmortem examinations. For HbA1c testing performed on 103 autopsy cases, a portable SD A1cCare (test) was used for the POC testing, along with a Cobas Integra 800 (comparative). There was a strong correlation between HbA1c levels from postmortem capillary and cardiac venous blood (regression equation, 0.000 + 1.000×), and between HbA1c levels of cardiac venous blood measured using the portable SD A1cCare as a POC test and the Cobas Integra 800 (regression equation, -0.532 + 1.080×). HbA1c levels measured up to 4 weeks following the autopsy with the SD A1cCare had a tendency to decline. The author concluded that HbA1c POC testing can be used during postmortem inspection and during autopsy to accurately identify patients who had uncontrolled diabetes mellitus.

A diabetic ketoacidosis in a context of hyperglycemia addiction

We herein present a case of a 20-year-old woman who suffered from type I diabetes mellitus and died from a diabetic ketoacidosis in a context of addiction to hyperglycemia. Diabetic ketoacidosis is a lethal complication of insulin-dependent diabetes mellitus, which can result from insulin therapy stoppage. This can occur voluntarily with suicidal intent or involuntarily due to treatment inaccessibility, forgotten injections, or material deficiency. A new possibility is investigated in our case study: hyperglycemia addiction. The patient was treated by insulin glargine and insulin aspartate. She regularly stopped insulin glargine injections seeking the asthenia sensation produced by hyperglycemia, keeping the insulin aspartate injections to treat the disabling symptom related to hyperketonemia.

Characterisation of the metabolome of ocular tissues and post-mortem changes in the rat retina

Time-dependent post-mortem biochemical changes have been demonstrated in donor cornea and vitreous, but there have been no published studies to date that objectively measure post-mortem changes in the retinal metabolome over time. The aim of the study was firstly, to investigate post-mortem, time-dependent changes in the rat retinal metabolome and secondly, to compare the metabolite composition of healthy rat ocular tissues. To study post-mortem changes in the rat retinal metabolome, globes were enucleated and stored at 4 °C and sampled at 0, 2, 4, 8, 24 and 48 h post-mortem. To study the metabolite composition of rat ocular tissues, eyes were dissected immediately after culling to isolate the cornea, lens, vitreous and retina, prior to storing at -80 °C. Tissue extracts were subjected to Gas Chromatograph Mass Spectrometry (GC-MS) and Ultra High Performance Liquid Chromatography Mass Spectrometry (UHPLC-MS). Generally, the metabolic composition of the retina was stable for 8 h post-mortem when eyes were stored at 4 °C, but showed increasing changes thereafter. However, some more rapid changes were observed such as increases in TCA cycle metabolites after 2 h post-mortem, whereas some metabolites such as fatty acids only showed decreases in concentration from 24 h. A total of 42 metabolites were identified across the ocular tissues by GC-MS (MSI level 1) and 2782 metabolites were annotated by UHPLC-MS (MSI level 2) according to MSI reporting standards. Many of the metabolites detected were common to all of the tissues but some metabolites showed partitioning between different ocular structures with 655, 297, 93 and 13 metabolites being uniquely detected in the retina, lens, cornea and vitreous respectively. Only a small percentage (1.6%) of metabolites found in the vitreous were only detected in the retina and not other tissues. In conclusion, mass spectrometry-based techniques have been used for the first time to compare the metabolic composition of different ocular tissues. The metabolite composition of the retina stored at 4 °C post-mortem is mostly stable for at least 8 h.

Postmortem biochemistry: Current applications

The results of biochemical analyses in specimens obtained postmortem may aid death investigation when diabetic and alcoholic ketoacidosis is suspected, when death may have been the result of drowning, anaphylaxis, or involved a prolonged stress response such as hypothermia, and in the diagnosis of disease processes such as inflammation, early myocardial infarction, or sepsis. There is often cross-over with different disciplines, in particular with clinical and forensic toxicology, since some endogenous substances such as sodium chloride, potassium chloride, and insulin can be used as poisons. The interpretation of results is often complicated because of the likelihood of postmortem change in analyte concentration or activity, and proper interpretation must take into account all the available evidence. The unpredictability of postmortem changes means that use of biochemical measurements in time of death estimation has little value. The use of vitreous humour is beneficial for many analytes as the eye is in a physically protected environment, this medium may be less affected by autolysis or microbial metabolism than blood, and the assays can be performed with due precaution using standard clinical chemistry analysers. However, interpretation of results may not be straightforward because (i) defined reference ranges in life are often lacking, (ii) there is a dearth of knowledge regarding, for example, the speed of equilibration of many analytes between blood, vitreous humour, and other fluids that may be sampled, and (iii) the effects of post-mortem change are difficult to quantify because of the lack of control data. A major limitation is that postmortem vitreous glucose measurements are of no help in diagnosing antemortem hypoglycaemia.

Postmortem diagnosis of diabetes mellitus and its complications

Diabetes mellitus has become a major cause of death worldwide and diabetic ketoacidosis is the most common cause of death in children and adolescents with type 1 diabetes. Acute complications of diabetes mellitus as causes of death may be difficult to diagnose due to missing characteristic macroscopic and microscopic findings. Biochemical analyses, including vitreous glucose, blood (or alternative specimen) beta-hydroxybutyrate, and blood glycated hemoglobin determination, may complement postmortem investigations and provide useful information for determining the cause of death even in corpses with advanced decompositional changes. In this article, we performed a review of the literature pertaining to the diagnostic performance of classical and novel biochemical parameters that may be used in the forensic casework to identify disorders in glucose metabolism. We also present a review focusing on the usefulness of traditional and alternative specimens that can be sampled and subsequently analyzed to diagnose acute complications of diabetes mellitus as causes of death.

Xanthochromia of the skull bone associated with HbA1c

The color of the surface of 105 skull bones (part of the parietal bone) was determined using a portable spectral colorimeter (spectro color(®)). By this means it was possible to characterize the color objectively according to the L*a*b* color system defined by the "International Commission de l'Eclairage" (CIE). Biochemical markers of carbohydrate metabolism, HbA1c from venous blood, and glucose/lactate concentrations from vitreous humor, were also determined, for assessment of the ante-mortem plasma glucose concentration using Traub's sum formula. As biochemical markers for lipid metabolism disorder, cholesterol, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) were all determined from venous blood. There is a significant correlation of bone yellowing with HbA1c (p<0.001) and age (p<0.001). The literature asserts a significant correlation between diabetic condition and yellowing of the skull bone. Despite efforts to find the substance responsible for the yellowing of the bone in chronic metabolism disorder, no significant correlation was found between bone color and lipoproteins/bone extracted lipid acids.

Comprehensive investigation of postmortem glucose levels in blood and body fluids with regard to the cause of death in forensic autopsy cases

The serum glucose level is regulated within a narrow range by multiple factors under physiological conditions, but is greatly modified in the death process and after death. The present study comprehensively investigated glucose levels in blood and body fluids, including pericardial fluid (PCF), cerebrospinal fluid (CSF) and vitreous humor, reviewing forensic autopsy cases (n=672). Right heart blood glucose level was often higher than at other sites, and the CSF glucose level was the lowest, showing greater dissociation in acute/subacute death cases. The glucose level was higher in the diabetic (high HbA1c) than in the non-diabetic (low HbA1c) group at each site (p<0.01-0.0001). Fatal diabetic ketoacidosis cases had evidently high glucose levels at each site; whereas in the non-diabetic group, blood glucose level was higher in fatal alcohol abuse, saltwater drowning, electrocution, cerebrovascular disease and sudden cardiac death due to ischemic heart disease. Fatal methamphetamine (MA) abuse, sepsis, malnutrition (starvation) and hypoglycemia due to antidiabetics showed markedly lower blood glucose levels. Ketones in bilateral cardiac blood and PCF were increased in diabetic ketoacidosis and fatal alcohol abuse as well as in most cases of hyperthermia (heatstroke), hypothermia (cold exposure) and malnutrition. These findings suggest that combined analysis of glucose, HbA1c and ketones in blood and body fluids is useful to investigate not only fatal diabetic metabolic disorders but also death processes due to other causes, including alcohol and MA abuse, as well as thermal disorders, sepsis and malnutrition.

Analysis of phenazepam and 3-hydroxyphenazepam in post-mortem fluids and tissues

Phenazepam is a benzodiazepine that is predominantly used clinically in the former Soviet states but is being abused throughout the wider world. This study reports the tissue distribution and concentration of both phenazepam and 3-hydroxyphenazepam in 29 cases quantitated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in a variety of post-mortem fluids (subclavian blood, femoral blood, cardiac blood, urine, vitreous humour) and tissues (thalamus, liver and psoas muscle). In 27 cases, the cause of death was not directly related to phenazepam (preserved (fluoride/oxalate) femoral blood phenazepam concentrations 0.007 mg/L to 0.360 mg/L (median 0.097 mg/L). In two cases, phenazepam was either a contributing factor to, or the certified cause of death (preserved (fluoride/oxalate) femoral blood 0.97 mg/L and 1.64 mg/L). The analysis of phenazepam and 3-hydroxyphenazepam in this study suggests that they are unlikely to be subject to large post-mortem redistribution and that there is no direct correlation between tissues/fluid and femoral blood concentrations. Preliminary investigations of phenazepam stability comparing femoral blood phenazepam concentrations in paired preserved (2.5% fluoride/oxalate) and unpreserved blood show that unpreserved samples show on average a 14% lower concentration of phenazepam and we recommend that phenazepam quantitation is carried out using preserved samples wherever possible.

Glucose-induced temporary visual recovery in primary open-angle glaucoma: a double-blind, randomized study

PURPOSE

To investigate the effect of topical glucose on visual parameters in individuals with primary open-angle glaucoma (POAG).

DESIGN

Double-blind, randomized, crossover study.

PARTICIPANTS

Nondiabetic pseudophakic patients with definite POAG were recruited; 29 eyes of 16 individuals participated in study 1. A follow-up study (study 2) included 14 eyes of 7 individuals.

INTERVENTION

Eyes were randomly allocated to receive 50% glucose or saline eye drops every 5 minutes for 60 minutes.

MAIN OUTCOME MEASURES

The contrast sensitivity and best-corrected logarithm of the minimum angle of resolution (logMAR).

RESULTS

The 50% glucose reached the vitreous in pseudophakic but not phakic individuals. Glucose significantly improved the mean contrast sensitivity at 12 cycles/degree compared with 0.9% saline by 0.26 log units (95% confidence interval [CI], 0.13-0.38; P < 0.001) and 0.40 log units (95% CI, 0.17-0.60; P < 0.001) in the follow-up study. The intraocular pressure, refraction, and central corneal thickness were not affected by glucose; age was not a significant predictor of the response.

CONCLUSIONS

Topical glucose temporarily improves psychophysical visual parameters in some individuals with POAG, suggesting that neuronal energy substrate delivery to the vitreous reservoir may recover function of "sick" retinal neurons.

Fatal metformin overdose: case report and postmortem biochemistry contribution

Metformin is an oral antihyperglycemic agent used in the management of type 2 diabetes mellitus. Lactic acidosis from metformin overdose is a rare complication of metformin therapy and occurs infrequently with therapeutic use. Fatal cases, both accidental and intentional, are extremely rare in clinical practice. Metformin is eliminated by the kidneys, and impaired renal function can result in an increased plasma concentration of the drug. In this report, we describe an autopsy case involving a 70-year-old woman suffering from diabetes mellitus and impaired renal function who received metformin treatment. Metformin concentrations in the peripheral blood collected during hospitalization and femoral blood collected during autopsy were 42 and 47.3 µg/ml, respectively. Lactic acidosis (29.10 mmol/l) was objectified during hospitalization. Furthermore, postmortem biochemistry allowed ketoacidosis to be diagnosed (blood β-hydroxybutyrate, 10,500 µmol/l). Death was attributed to lactic acidosis due to metformin intoxication. Increased plasma concentrations of the drug were attributed to severely impaired renal function. The case emphasizes the usefulness of performing exhaustive toxicology and postmortem biochemistry towards the more complete understanding of the pathophysiological mechanisms that may be involved in the death process.

Postmortem chemistry update part I

Postmortem chemistry is becoming increasingly essential in the forensic pathology routine and considerable progress has been made over the past years. Biochemical analyses of vitreous humor, cerebrospinal fluid, blood and urine may provide significant information in determining the cause of death or in elucidating forensic cases. Postmortem chemistry may essentially contribute in the determination of the cause of death when the pathophysiological changes involved in the death process cannot be detected by morphological methods (e.g. diabetes mellitus, alcoholic ketoacidosis and electrolytic disorders). It can also provide significant information and useful support in other forensic situations, including anaphylaxis, hypothermia, sepsis and hormonal disturbances. In this article, we present a review of the literature that covers this vast topic and we report the results of our observations. We have focused our attention on glucose metabolism, renal function and electrolytic disorders.