Biomedical subjects
D J Pounder
Publications and source records attributed to D J Pounder.
Post mortem markers of chronic alcoholism.
We compared the post mortem diagnostic value of gamma-glutamyltransferase (GGT), carbohydrate-deficient transferrin (CDT), alcoholic liver disease (ALD), blood alcohol concentration (BAC), the presence of multiple bruises and poor hygiene of the feet as markers of chronic alcoholism (heavy continuous drinking) in 32 alcoholics with 32 age-sex matched controls drawn from a forensic autopsy population. Alcoholics and controls were selected on the basis of positive and negative medical history but controls were excluded if BAC exceeded 70 mg%. Femoral venous blood, urine and vitreous humour alcohol concentrations were determined by headspace gas chromatography (GC). BAC was positive in 19 alcoholics (mean 234 mg%, range 2-570 mg%) and six controls (mean 32 mg%, range 2-52 mg%). Serum GGT was measured by a kinetic photometric method, and CDT by both isoelectric focusing/laser densitometry and by a commercial radioimmunoassay kit (CDTect). Features of alcoholic liver disease were graded histologically using two weighted scoring systems. Eleven alcoholics tested positive for GGT, CDTq and ALD, nine were positive for two tests, five for one test and three were negative for all three tests. No controls were positive for all three tests but six were positive for two tests and nine for only one test; 17 were negative for all three tests. Using the normal clinical cut-off values GGT, CDTq and CDTect gave poor specificity which was improved at moderate cost to sensitivity by raising cut off values for each test. Comparison of receiver operating characteristic curves, likelihood ratios and post-test odds showed CDT to be the best individual test, followed by ALD and GGT. Quantitation of CDT by IEF/laser densitometry performed slightly better than MAEC/RIA by CDTect. CDT shows considerable promise as a post mortem marker of chronic alcoholism.
Postmortem diffusion of ingested and aspirated paint thinner.
Post mortem diffusion of paint thinner (toluene/ethyl acetate/isobutanol 8:1:1 v/v) from gastric residue (25 ml or 100 ml) and airways contamination (25 ml) was assessed in a human cadaver model, with sampling after 24 h at room temperature. Four torso blood samples showed less toluene diffusion after gastric instillation (0.5-3.8 micrograms/ml) than after tracheal instillation (10.5-421 micrograms/ml). Isobutanol diffused more readily than toluene with four torso blood samples 1.8-256 micrograms/ml after gastric instillation and 26-576 micrograms/ml after tracheal instillation. Following 25 ml gastric instillation, toluene concentrations (microgram/ml or microgram/mg) were: pericardial fluid 0.7-4.0; bile 0.5-0.6; urine 0-0.6; brainstem 1.1; lung 0.4-4.4; liver 0-162; spleen 0.6-0.7; kidneys 0.4-0.6; peri-renal fat 0.3-30.3; psoas muscle 0.3-0.8; concentrations of toluene and isobutanol were markedly higher in the left lobe of the liver than the right. Ethyl acetate was mostly undetectable in tissue samples but variably present in five blood samples: 0-21.2 micrograms/ml following 25 ml or 100 ml gastric instillation and 0-198 micrograms/ml following 25 ml tracheal instillation. Ethyl acetate was always detectable in pericardial fluid but not always detectable in gastric contents. We conclude that post mortem diffusion of toluene from gastric residue or airways contamination is unlikely to compromise the analytical validity of femoral venous blood samples, brain, or liver from deep within the right lobe. Analysis of pericardial fluid and gastric contents allows identification of ethyl acetate and isobutanol thus implicating thinner solution.
Postmortem diffusion of drugs from gastric residue: an experimental study.
Postmortem drug diffusion from gastric residue was assessed in a human cadaver model. Fifty milligrams of amitriptyline (Ami) and 5 g of paracetamol (Par) suspended in 350 ml of 10% methanol, 0.1 N HCl, and 50 ml urograffin with 5 g lithium carbonate (alkaline model) or without lithium (acidic model) was instilled into the stomach through an esophageal tube via a neck dissection. Multiple samples were obtained after 48 h at room temperature (range in mean hourly room temperature: 15.6-20.7 degrees C, n = 9). The pH of the gastric contents (alkaline model range = 8.3-8.9, n = 5; acidic model range = 3.4-3.8, n = 5) had no significant effect. Drug diffusion was most marked in the left lung base, with drug concentrations (micrograms/g) of 0.1-13.9 for Ami, 65-524 for Par, and 13-161 for lithium. Similarly affected were the left lobe of the liver (Ami, 0.1-54.9; Par, 7-218; lithium, 7-39), the spleen (Ami, 0.6-24.3; Par, 104-663; lithium, 27-106), and pericardial fluid (Ami, 0-4.5; Par, 48-641; lithium, 12-56). Diffusion into gallbladder bile, cardiac blood, aortic blood, and blood of the inferior vena cava was less severe. The left kidney and left lung were more severely affected than the right kidney and lung, and similarly the left and right psoas muscles. Least affected was the right anterior lobe of the liver and the lung apexes. This phenomenon may significantly influence drug concentrations in liver and in blood samples obtained from the torso, and consequently liver/blood drug ratios. To circumvent the problem of postmortem drug diffusion from the stomach, it is recommended that blood be sampled from a peripheral vessel, skeletal muscle from a limb, liver from deep within the right lobe, and lung from the apex rather than the base.
Site to site variability of postmortem drug concentrations in liver and lung.
We evaluated postmortem diffusion of gastric drug residue into tissues and blood in eight suicidal overdoses. Analyses were performed on liver (five sites), lung (four sites), spleen, psoas muscle and kidney (left and right), blood (peripheral and torso), vitreous, pericardial fluid, bile and, urine as well as residual gastric contents. Standard analytical techniques and instrumentation gas chromatograph/mass spectrometer and high performance liquid chromatography (GC-MS and HPLC) were used throughout. These case studies confirm previous studies of an animal and human cadaver model of gastric diffusion, in that in several instances there was drug accumulation in the left posterior margin of the liver and, to a lesser extent, the left basal lobe of the lung. Uncontrollable variables, such as postmortem interval, refrigeration before autopsy, and position of the body appear to influence significantly drug accumulation in a specific site. We suggest that autopsy sampling techniques should be standardized on blood taken from a ligated peripheral (preferably femoral or external iliac) vein, and liver from deep within the right lobe.
Urinary catecholamines as markers of hypothermia.
Although raised urinary CA levels provide good supportive evidence of prolonged agonal stress in hypothermic deaths, the CA index is not, in our experience, of particular diagnostic significance.
Drug accumulation and elimination in Calliphora vicina larvae.
Calliphora vicina larvae were fed on drug-laden muscle from three suicides involving amitriptyline, temazepam and a combination of trazodone and trimipramine; triplicate daily harvestings were analysed. The limit of detection for all four drugs was 0.01 micrograms drug/g larvae. Mean drug concentrations (microgram/g) in the initial muscle were:amitriptyline, 2.68; temazepam, 4.04; trazodone, 21.56; and trimipramine, 19.58. Larval rearings for days 4-8 (15 larval samples per drug) had mean and ranges of drug concentrations (microgram/g) of 0.10 (r, 0.02-0.24) for amitriptyline; 0.52 (r, 0.26-0.78) for temazepam; 0.13 (r, 0.05-0.32) for trazodone; and 0.28 (r, 0.10-0.59) for trimipramine. After day 8 there was a precipitous fall in larval drug concentrations associated with pupariation. At day 11 ranges of drug concentrations (microgram/g) were: amitriptyline, < 0.01-0.01; temazepam, 0.01-0.08; trazodone, < 0.01-0.01; and trimipramine, 0.04-0.04. Day 16 pupae had corresponding ranges (microgram/g) of < 0.01, 0.01-0.01, < 0.01 and < 0.01-0.02. Transfer to drug-free food at day 5 led to similar falls in drug concentrations (microgram/g) from day 5 to day 6: 0.08-0.03 for amitriptyline, 0.61-0.09 for temazepam, 0.13-0.01 for trazodone, and 0.30-0.02 for trimipramine. The results show considerable variation in larval drug concentrations, both at the same developmental stage and at different stages of the life cycle, under conditions which closely reflect case situations. In practice, the precipitous decrease in drug concentrations in non-feeding larvae and at pupariation make it desirable to sample only larvae actively feeding on a corpse.
Postmortem diffusion of alcohol from the stomach.
We explored postmortem ethanol diffusion from the stomach using a human cadaver model with multiple blood site sampling. In all, 400 ml of alcohol solution (5%, 10%, 20%, or 40% methanol and ethanol weight/volume in water) was introduced into the stomach by oesophageal tube. Blood methanol concentrations correlated with ethanol concentrations (methanol range, 1-676 mg%; ethanol range, 1-531 mg%; r = 0.9973). The pattern of ethanol diffusion showed marked between-case variability. Typically, concentrations were highest in pericardial fluid and, in decreasing order, in left pulmonary vein, aorta, left heart, pulmonary artery, superior vena cava, inferior vena cava, right heart, right pulmonary vein, and femoral vein. Diffusional flux was broadly proportional to the concentration of ethanol used. It was time-dependent (as assessed by 24-h and 48-h sampling) and markedly inhibited by refrigeration at 4 degrees C. After gastric instillation of 400 ml of 5% solution for 48 h at room temperature in paired cadavers, ethanol concentrations (mg%) were as follows: pericardial fluid 135, 222; aorta 50, 68; left heart 77, 26; right heart 41, 28; femoral vein 0. Using a 10% solution, ethanol concentrations (mg%) were as follows: pericardial fluid 401, 255; aorta 129, 134; left heart 61, 93; right heart 31, 41; femoral vein 5, 7. Introducing 50 ml of 10% alcohol solution into the oesophagus after oesophagogastric junction ligation produced similar aortic blood ethanol concentrations. This suggests that postmortem gastrooesophageal reflux and diffusion from the oesophagus is the mechanism of artefactual elevation of aortic blood ethanol.(ABSTRACT TRUNCATED AT 250 WORDS)
Creatine kinase BB and neuron-specific enolase in cerebrospinal fluid in the diagnosis of brain insult.
Cerebrospinal fluid (CSF) markers provide useful information about the extent of brain damage. These biochemical indices may also be used when postmortem histopathological examination does not confirm antemortem brain insult. Seven biochemical parameters--creatine kinase (CK), creatine kinase BB isoenzyme (CK-BB), lactate dehydrogenase (LDH), gamma-glutamyltransferase, aldolase, leucine aminopeptidase (LAP), and neuron-specific enolase (NSE)--were analyzed in CSF from 82 cadavers. Case studies were categorized into one of four diagnostic groups. There were 15 cases of head trauma, 23 of hypoxia (hangings, carbon monoxide, and drug poisonings), 23 sudden cardiac death, and 21 miscellaneous cases. The degree of craniocerebral trauma was graded. In CSF there was a statistically significant correlation between the severity of craniocerebral trauma and levels of CK, CK-BB, aldolase, LDH, and LAP. CSF CK-BB [median U/L (range)] for the groupings of head trauma, hypoxia, sudden cardiac death, and miscellaneous were, respectively, 873 (1-12,100), 26 (2-2,780), 16 (1-42), and 18 (0-2,780). Corresponding CSF CK levels were 9,370 (28-67,842), 101 (18-36,840), 180 (10-29,622), and 264 (17-26,556). There were no statistical significant differences among the NSE concentrations in the four diagnostic groups. The testing of biochemical markers could be a reliable indicator of the degree of brain insult in support of morphological studies.
Estimating blood alcohol from urinary alcohol at autopsy.
Urine alcohol concentration (UAC) and blood alcohol concentration (BAC) measured by gas chromatography were available from 435 medicolegal autopsies. Simple linear regression with BAC as outcome variable and UAC as predictor variable (range, 3-587 mg%) gave the regression equation BAC = -5.6 + 0.811UAC with 95% prediction interval +/- 0.026 square root of [9465804 + (UAC-213.3)2] and 99% prediction interval +/- 0.034 square root of [9465804 + (UAC-213.3)2]. The standard error of the slope was 0.013 and the 95% confidence interval for the slope 0.785-0.837. In practice, a BAC of 80 mg% is predicted with 95% certainty by a UAC of 204 mg% and similarly a BAC of 150% by a UAC of 291 mg%. The prediction interval is too wide to be helpful in the assessment of an individual case fatality. The UAC is useful in corroborating but not in predicting BAC.
Organomegaly in chronic alcoholics.
We compared the weights of the brain, heart, spleen, lungs, liver, and kidneys, uncorrected and corrected for body surface area (BSA) and body mass index (BMI), of 50 alcoholics with 50 forensic controls matched for sex, age, and body weight. With the exception of combined renal weight corrected for BSA and BMI, no significant differences were found in organ weights between the two groups. Glomerular diameter corrected for BSA was significantly greater in alcoholics than controls. It appears that nephromegaly and glomerulomegaly are both population markers for alcoholism. In alcoholics, there was no correlation between the microscopic degree of steatosis and glomerulomegaly. In controls, renal glomerular diameter was greater with increasing severity of hepatic steatosis, probably as a reflection of obesity.
Zopiclone poisoning: tissue distribution and potential for postmortem diffusion.
Zopiclone is the first cyclopyrrolone hypnotic and is chemically unrelated to any existing drug. The authors studied the tissue distribution and postmortem redistribution of zopiclone in a fatal suicidal overdose. A 29-year-old female weighing 64 kg had cardiac blood ethanol 153 mg% and zopiclone blood concentrations in the range 0.9-2.0 microgram/ml in 10 distinct sampling sites. After 40 h at room temperature the range was 0.9-1.8 micrograms/ml in 15 samples. Portal venous blood and urine concentrations were 3.0 and 10.5 micrograms/ml, respectively. Tissue concentrations (microgram/g) were spleen 5.8, peri-renal fat 5.0, psoas muscle 3.3, brainstem 2.8, gastrocnemius muscle 1.9, myocardium 1.6, and kidney 1.7. Eight liver samples had concentrations in the range 0.5-4.9 micrograms/g, with highest concentrations in the left lobe and adjacent to the gallbladder, probably reflecting postmortem diffusion from gastric residue (700 ml, 55.1 micrograms/ml) and bile (14.1 micrograms/ml). Of six lung samples, paired upper and middle samples had concentrations in the range 2.1-2.3 micrograms/g, the right postero-basal 1.3 micrograms/g and the left postero-basal 3.4 micrograms/g. Drug concentration in putrefactive pleural fluid was also higher on the left (2.1 micrograms/ml) than the right (1.4 micrograms/ml), probably reflecting postmortem diffusion from gastric residue. The authors conclude that zopiclone showed little preferential concentration in solid organs and consequently has relatively stable postmortem blood concentrations, with little drug redistribution artefacts. Postmortem diffusion from gastric drug residue elevates drug levels in the left lobe of the liver and left lung lower lobe.
Vitreous alcohol is of limited value in predicting blood alcohol.
Vitreous humour alcohol concentration (VHAC) and blood alcohol concentration (BAC) measured by gas chromatography were available from 345 medico-legal autopsies. Simple linear regression with BAC as outcome variable and VHAC as predictor variable (range 1-705 mg%) gave the regression equation BAC = 3.03 + 0.852 VHAC with 95% prediction interval +/- 0.019 square root of [7157272 + (VHAC - 189.7)2] and 99% prediction interval +/- 0.025 square root of [7157272 + (VHAC - 189.7)2]. The residual standard deviation of VHAC was 26 mg%, the standard error of the slope 0.0098 and the 95% confidence interval for the slope 0.833-0.871. In practice a BAC of 80 mg% is predicted with 95% certainty by a VHAC of 150 mg% and similarly a BAC of 150 mg% by a VHAC of 232 mg%. The prediction interval is too wide to be of real practical use. Previous authors have provided various formulae, including a simple conversion factor, to predict BAC from VHAC without taking into account the uncertainty of the prediction for an individual subject. A re-analysis of the raw data from previous publications gave in most instances regression equations significantly different from the authors' own.
Postmortem changes in blood amitriptyline concentration.
Detailed toxicological studies were undertaken on two suicides by amitriptyline overdose, one with salicylate also. In the first case, 10 initial blood samples taken 21 h after body discovery and an estimated 28 1/2 h after overdose had drug concentration (mg/L) ranges of 2.5-12 for amitriptyline (AM), 0.7-3.1 for nortriptyline (NOR), and 81-244 for salicylate (SAL). Ten blood samples taken 42 h later showed corresponding ranges of 1-39 AM, 0.6-7.0 NOR, and 86-310 SAL. Sample haemoglobin concentrations (range, 8.7-23.5 g/dl) did not correlate with drug concentrations. Postmortem increase in pulmonary vein AM concentration occurred more rapidly than in the pulmonary artery, likely reflecting relative ease of diffusion across the vessel walls from lung (AM, 60 mg/kg). In nine tissue samples, drug concentrations (mg/kg) were highest in the liver: AM, 301; and SAL, 670. Considerable drug residue was present in gastric contents, duodenal contents, and seven sequential small bowel contents. In both cases, sanguineous putrefactive pleural fluid showed higher AM concentrations on the left than on the right (2.0 vs 1.4 and 23 vs 16), likely reflecting diffusion from gastric drug residue. The detailed case data illustrate the intensity and complexity of postmortem drug diffusion from reservoirs in solid organs, such as the lungs, and unabsorbed gastric residue, into the blood and putrefactive fluids.
Postmortem redistribution and degradation of dothiepin. Human case studies and an animal model.
Two suicides took estimated maximum dothiepin doses of 765 and 1875 mg, respectively. Initial drug levels in nine and 12 blood samples were 0.26-1.85 and 4.08-23.98 mg/L, with highest concentrations in the pulmonary veins. Pulmonary artery concentrations rose markedly over 18 h: 0.32 rising to 0.9, and 6.54 rising to 19.53 mg/L. Peripheral blood concentrations were relatively stable. Concentrations in liver, heart, lung, and skeletal muscle were, for case 1, 4.3, 2.92, 18.6, and 1.1 mg/kg; and, for case 2, 52, 16.8, 73.9, and 8.98 mg/kg. New Zealand white female rabbits (2.4-3.2 kg) given 20 mg dothiepin hydrochloride intravenously were killed with pentobarbital after 1 h. Blood was sampled from the thorax, infra-renal inferior vena cava, and supra-renal inferior vena cava at 0, 1/2, 1, 4, 8, 12, and 24 h postmortem in paired animals. Liver, heart, lung, and skeletal muscle were sampled at 0 and 24 h. Mean dothiepin levels in thoracic blood rose from 0.43 mg/L at time 0 to 1.73 at 8 h and then fell to 0.61 at 12 h, likely reflecting initial redistribution from the lungs (63.4 mg/kg at time 0 and 27.3 mg/kg at 24 h) followed by putrefaction-associated bacterial degradation. Falls in blood drug levels associated with putrefaction were not seen in the human cases. Interpretation of postmortem dothiepin blood concentrations is complicated by pronounced interindividual variations in in vivo pharmacokinetics, the postmortem redistribution phenomenon, and variable drug degradation by bacteria.
Postmortem changes in blood tranylcypromine concentration: competing redistribution and degradation effects.
Site and temporal changes in tranylcypromine (TCP) and lithium concentrations in blood were studied in a human poisoning case. Blood samples from peripheral vessels and six central vessels were obtained at 0, 6, 24, 48 and 72 h after starting the autopsy. Nine tissue samples were obtained on completion. TCP showed preferential concentration in liver (2.21 micrograms/g) and brainstem (2.46 micrograms/g). There was a moderate post mortem redistribution phenomenon with TCP concentrations lowest in peripheral blood (0.17 micrograms/ml) at 0 h and highest in central vessels at 24 h (0.52 micrograms/ml). At 72 h blood TCP concentrations fell below those at 0 time but the samples showed marked putrefactive changes. Control blood samples spiked with TCP and incubated for 48 h at 37 degrees C showed a 58% fall in drug concentration. By contrast with TCP, lithium, which has a small Vd (0.8 l/kg) and is chemically stable, did not show this pattern of change in blood concentration. The site and temporal differences in TCP concentration in blood can be explained by the competing effects of post mortem redistribution and drug degradation. Redistribution is an early post mortem phenomenon characterised by diffusion, along a concentration gradient, from drug reservoirs in solid organs into adjacent blood vessels. Drug degradation is a later phenomenon associated with putrefactive change.
Drug analysis in fly larvae.
We reared larvae of Calliphora vicina on human skeletal muscle obtained from cases of suicidal overdose with co-proxamol (propoxyphene and acetaminophen) and amitriptyline. After 4 days, third-instar larvae were either transferred to drug-free muscle or continued to feed on drug-laden muscle for a further 2 days prior to harvesting. Amitriptyline and nortriptyline were detected in both groups of larvae, but propoxyphene was only in those fed continuously on drug-laden muscle, and acetaminophen was in neither. Drug concentrations in muscle food source were amitriptyline 0.48 microgram/g, nortriptyline 0.38 microgram/g, propoxyphene 0.99 microgram/g, and acetaminophen 14.13 micrograms/g. For triplicate rearings, the mean ratios of drug concentrations in larvae to food source were amitriptyline, 0.56; nortriptyline, 0.5; and propoxyphene, 0.06. In triplicate rearings, no drug or metabolite was detected in puparia, puparial cases, or imagos. We conclude that the absence of a drug in maggots is not necessarily an indication that the drug was not present in significant concentrations in the food source. The malpighian tubules and the "nephrocytes" of fly larvae appear capable of eliminating different drugs with varying efficiency.
Why are the British hanging themselves?
Suicide statistics for Britain (England and Wales) from 1950 to 1990 are analysed. A rising suicide rate among males, particularly the young, is associated with an increased use of hanging as a suicide method. The same trend is not seen among females. Death by hanging can seldom be concealed or regarded as other than suicide, so statistics for suicidal hanging are likely accurate. Increased suicidal hangings cannot be explained by changes in the availability or awareness of the method and must reflect change in choice of method. Hanging as a suicide method has been historically unpopular in Britain because of the dishonorable repute associated with its use for judicial execution. The abolition of judicial hanging in Britain in 1965 may have led to an increased acceptability of hanging as a suicide method. The resultant increased use of this highly lethal method may be one underlying cause of the increased numbers of completed suicides and the rise in the suicide rate.