Prostaglandin F2a (PGF2a): an inadequate marker of the vitality of wounds?

We have studied the viability of PGF2a as a vitality marker in skin wounds. Incised vital skin wounds and homolateral control pieces of skin were obtained from 20 autopsies performed at the Institute of Legal Medicine of Coimbra University (Portugal). We have also studied 10 fresh skin samples from the Department of Dermatology of the University Hospital (Granada). Our results show that PGF2a is not suitable for the diagnosis of the vitality of wounds because of its irregular behaviour.

Differences in the kinetic properties, effect of calcium and sensitivity to inhibitors of paraoxon hydrolase activity in rat plasma and microsomal fraction from rat liver

The properties of a rat hepatic microsomal enzyme that hydrolyses O,O-diethyl-p-nitrophenylphosphate (paraoxon) were studied and compared to the paraoxon hydrolase activity found in rat plasma. The pH stability for both enzyme activities was optimum between pH 6.0 and 9.0. An overall analysis of the data showed that the microsomal fraction was less resistant to the effect of the pH than plasma. The kinetic constants for heat inactivation evaluated for paraoxonase in rat plasma and liver microsomal fraction indicate that paraoxonase tends to inactivate faster in rat liver microsomes than in rat plasma. The apparent activation energies of the heat inactivation process were 77.7 and 61.1 kcal/mol for rat plasma and microsomal fraction, respectively. Enzyme activity was lost after both dialysis and incubation with EDTA and partially restored by the addition of calcium. In rat plasma samples the requirement for calcium was absolute (essential activator) while in the microsomal fraction the reaction may occur, to a minimum extent, in the absence of the activator (non-essential activator). Calcium restored 85% activity when added immediately after EDTA; restored activity decreased when the time interval between addition of EDTA and calcium was increased. Other metals were not able to restore activity previously inhibited by EDTA or dialysis. The response to several inhibitors (EDTA, Mn, Co, Zn, Ba, Mg, Cu, La, Hg and p-hydroxy-mercuribenzoate) of rat plasma and microsomal fraction was studied, determining the type of inhibition and the inhibition constants. Plasma enzyme was always more resistant than liver sample to the effect of the inhibitors and showed different types of inhibition than the liver microsomal fraction. In general we found more differences than analogies between the rat plasma and liver enzyme which suggests the presence of two enzymes or two different forms of the same enzyme. Furthermore the existence of an EDTA-resistant fraction in rat liver microsomes suggests that more than one enzyme capable of hydrolysing paraoxon is present in the microsomal fraction of rat liver.

Analysis of the HUMTH01 allele frequencies in the Spanish population

Genetic marker typing based on DNA amplification by the polymerase chain reaction (PCR) increasingly is being employed in forensic casework and for paternity testing. The allele frequencies were determined using PCR for 120 unrelated Spanish Caucasians for the locus HUMTHOH1. Six alleles were observed, with frequencies ranging from 0.013 (allele 11) to 0.254 (allele 10). The observed heterozygosity was 75.8%, and the power of discrimination is 0.92. The genotype distribution meets Hardy-Weinberg expectations.

Lipoproteins and apolipoproteins in pericardial fluid: new postmortem markers for coronary atherosclerosis

Determinations of lipoproteins (HDL-cholesterol and LDL-cholesterol) and various apolipoproteins (Apo A-I, Lp(a) and Apo B-100) were performed in postmortem pericardial fluid. Studies were carried out on 77 cadavers: 41 adult subjects with a morphological and biochemical diagnosis of intermediate or fresh myocardial infarction and 36 adults with no previous history of myocardial infarction. HDL and LDL were determined by enzymatic methods. Both apolipoproteins (A-I and B-100) were quantified by radio-immunoassay methods and Lp(a) was measured by enzyme immunoassay. Cases with severe atherosclerosis of coronary arteries showed higher levels of Apo B in pericardial fluid compared to cases without atherosclerosis. A significant increase of Apo B was found in cases with a positive diagnosis of myocardial infarction. Due to the high level of Apo B in pericardial fluid, a decrease in the LDL/Apo B ratio, along with a pronounced increase in the Apo B/Apo A ratio, was detected. The determination of Apo B in pericardial fluid can be a useful parameter to be included in biochemical analysis for the postmortem diagnosis of myocardial infarction related to coronary atherosclerosis.

Analysis of short tandem repeat (STR) HUMVWA in the Spanish population

Amplification by polymerase chain reaction (PCR) of variable number of tandem repeat (VNTR) loci and subsequent typing by electrophoresis and silver staining has become a useful tool for identity testing. One viable group of genetic markers amenable to amplification by PCR is the short tandem repeat (STR) loci. A horizontal discontinuous polyacrylamide gel electrophoresis (PAGE) method was used to type the amplified products of the STR HUMVWA. Typing for VWA of 120 unrelated Spanish Caucasians was done. Six alleles were observed with frequencies in the range 0.096-0.242. The genotype distribution meets Hardy-Weinberg expectations (0.25 < P < 0.50). The heterozygosity was 73.3% and the discrimination power (DP) 0.94. Simultaneously, in a small sample of families (n = 24) no new mutations could be found.

Comparison of the CAGE questionnaire versus some biochemical markers in the diagnosis of alcoholism

We have compared the individual sensitivity, specificity and predictive value of the CAGE questionnaire, plasma levels of ethanol and acetate, mean corpuscular volume (MCV), gamma glutamyl transferase (GGT), and glycosylated haemoglobin (Hb A1c) in a group of 50 healthy non-alcoholic controls and 31 patients with non-alcoholic liver disease (Group I), and in a second group of 40 alcoholic patients (Group II). Taken individually, the CAGE questionnaire was the most efficient (96% sensitive and 92% specific), followed by plasma levels of acetate (74% sensitive and 85% specific), MCV (64% sensitive and 91% specific) and GGT (72% sensitive and 80% specific). Hb A1c did not show any statistically significant difference between alcoholics and non-alcoholics and thus is of no use as a screening test for the diagnosis of alcoholism. Furthermore, we attempted to design a discrimination procedure to separate alcoholics from controls and patients with non-alcoholic hepatic diseases using a combination of the most promising tests. The most powerful discrimination model was constructed with the four questions of the CAGE questionnaire. The percentage of correct classifications using this model was 99% from Group I (specificity) and 90% from Group II (sensitivity). The CAGE questionnaire was itself so useful as a discriminant in our sample that no increased diagnostic efficacy was noticed on adding any of the other tests. Using objective variables (MCV, acetate and GGT) as discriminants, we could correctly classify 96% of subjects from Group I (specificity) and only 64% from Group II (sensitivity).

Sequential multiplex amplification (SMA) of genetic loci: a method for recovering template DNA for subsequent analyses of additional loci

A method called Sequential Multiplex Amplification (SMA) has been developed whereby a limited amount of DNA extracted from a sample can be reutilized for several single polymerase chain reaction (PCR) amplifications. The method involves recovery of genomic template DNA by microfiltration of PCR-amplified samples. Up to 5 different loci have been typed, each in a single system PCR-based assay, beginning with a test quantity of 5 ng template DNA. Genotypes of the DNA donors were compared with those obtained from individual amplifications and shown to be identical. This could be a useful technique for typing a number of loci from a limited amount of DNa and to recover template DNA from samples previously subjected to PCR. Obviously, when small quantities of template DNA are available, this technique can prove quite useful.

Clinical and pathological findings in fatal 1,3-dichloropropene intoxication

1. A 27-year-old, previously healthy, worker accidentally drank a solution containing 1,3-dichloropropene. 2. He developed gastrointestinal distress, adult respiratory distress syndrome, haematological and hepatorenal functional impairment and died after 40 h. 3. Damage to the pancreas was also thought to have been caused by the chemical as part of a multiorgan disorder.

Microwave oven digestion procedure for atomic absorption spectrometry analysis of bone and teeth

The purpose of this study was to develop a new method for determination of the mineral element in teeth and bone using a microwave digestion procedure coupled to atomic absorption spectrometry. Samples were ashed at 450 degrees C for 4.5 h and subsequently digested in a microwave oven at maximum power (600 W) for 10 s using a Teflon closed Parr bomb. This method permits the rapid dissolution of the biological samples, avoiding operations such as slicing and cutting which often introduce alterations in sample homogeneity and may contribute to their contamination. The analysis of Na, K, Ca, Mg, Fe, Zn, Ba, Cd and Pb showed good reproducibility, precision and accuracy as compared with the certified values for the IAEA H-5 animal bone. Average concentration for those elements in permanent teeth obtained from children aged 11-18 years by orthodontics are given.

Paraoxonase activity in human pericardial fluid: its relationship to coronary artery disease

Pericardial fluid paraoxonase activity was compared with 3 biochemical markers of atherosclerosis (HDL, LDL/HDL ratio and Apolipoprotein A-I) and a significant association was found. When the paraoxonase activity in pericardial fluid samples was separated into 2 groups according to the degree of coronary atherosclerosis (slight and severe), most of the cases showing low levels of paraoxonase activity also showed severe coronary atherosclerosis. In addition, paraoxonase activity in pericardial fluid was found to be statistically correlated with HDL levels, which agrees with the results reported in serum.

Characterization of paraoxonase activity in pericardial fluid: usefulness as a marker of coronary disease

In this study, the presence of paraoxonase activity in pericardial fluid was demonstrated. A comparison of some properties, such as optimum pH, stability versus pH, heat inactivation, effect of inhibitors, isoelectric point and kinetic parameters (Km and Vmax), between plasma and pericardial fluid paraoxonase was made. The properties studied were practically identical. The enzyme activity in pericardial fluid was tested as a marker in the postmortem diagnosis of myocardial infarction. The paraoxonase activity in the myocardial infarction group (47 cases) was lower than in the control group (40 cases), but the difference was not significant.

[Acetate metabolism: experimental study]

Plasma levels of ethanol and acetate, which is the end product of hepatic ethanol oxidation, have been studied in 60 rats. Animals were divided into two groups: 1) Control rats, and 2) Alcohol-treated rats. Ethanol and acetate were measured without any previous handling (endogenous levels) and after intraperitoneal injection of a single dose of ethanol. Blood specimens were taken at 30, 60, 120, 180 and 240 minutes after ethanol injection. Plasma levels of ethanol and acetate were performed by Head Space Gas Chromatography. Alcohol-treated animals had higher plasma acetate levels than control ones. There were statistically significant differences for acetate between both groups of rats at 0, 30, 120 and 180 minutes.

Rat liver paraoxonase: subcellular distribution and characterization

The subcellular localization and some biochemical properties of rat liver paraoxonase have been studied in order to establish a correlation with plasma enzyme. The whole paraoxonase activity was found in the microsomal fraction. Rat plasma and liver paraoxonase showed similar optimum pH (8.5), Km (0.4 mM) and calcium requirement, but differed in the response to several inhibitors.

Partial purification of paraoxonase from rat liver

A method for the partial purification of rat liver paraoxonase is presented. The method consists of the following steps: preparation of microsomes, solubilization with Triton X-100, adsorption on hydroxylapatite and chromatography on DEAE-52 cellulose. A partially purified preparation of rat liver paraoxonase has been obtained, showing a specific activity of 422 mU/mg with a yield of about 22% and a purification factor of 77-fold.

Cathepsin D as a vitality marker in human skin wounds

This paper shows the results obtained by studying the lysosomal enzyme Cathepsin D as a potential marker for the vitality of wounds in human specimens. We have analyzed 53 samples using enzymological and histological techniques. Our results show the ability of Cathepsin D to establish the vital origin of wounds inflicted 5 minutes or less before death, where the specific activity of cathepsin D reached 0.055 units at the wound edge and 0.01 units in their respective controls (P < 0.001). As previously demonstrated in an experimental series, Cathepsin D seems to be a very useful marker of high forensic interest in especially difficult cases. Further studies are in progress to check the influence of different factors such as drugs intake and clinical conditions on Cathepsin D activity.

Composite PAGE: an alternate method for increased separation of amplified short tandem repeat alleles

Genetic typing of short tandem repeat (STR) loci may require electrophoretic separation techniques which, depending on the locus, can resolve alleles differing in size by only 2, 3 or 4 base pairs (bps). Many such loci can be separated by horizontal, discontinuous polyacrylamide gel electrophoresis (hd-PAGE). However, some loci present particular separation challenges. A composite (or step) gel system consisting of 2 zones, anodal and cathodal, which differ by pore size and ionic strength, has been developed to augment resolution of DNA fragments without a need for additional electrophoretic equipment. Depending on pore size, as well as ionic strength, initial migration can be increased or decreased to effect resolution. When compared with hd-PAGE, this composite gel electrophoretic system can result in enhanced resolution of PCR amplified STR alleles.

Postmortem stability of lung surfactant phospholipids

The postmortem stability of the main phospholipids of lung surfactant-phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl inositol (PI), phosphatidyl serine (PS) and sphingomyelin (S) in three different deaths; one caused by fresh-water drowning, one by salt-water drowning, and one from a sodium-pentobarbital overdose has been studied. The drug overdose was considered the control because there was no surfactant involvement. The results show the stability of these kinds of lipids in the first 24 h, with a progressive decrease from 48 h on until 96 h, with a significant correlation to the time of P less than 0.01 in most cases.

Decrease of phosphofructokinase activity in relation to the pathogenesis of triorthocresyl-phosphate-induced delayed neuropathy

The in vivo effect of a single dose of the neuropathic compound triorthocresyl-phosphate (TOCP) on phosphofructokinase (PFC, E.C. 2.7.1.11) and its relation with the initiation step (inhibition and aging of neuropathy target esterase, NTE) in the TOCP-induced delayed neuropathy have been studied. Hens were treated with a neurotoxic dose of TOCP (500 mg/kg, p.o.) and with a protective compound (Phenylmethanesulfonyl fluoride, PMSF, 30 mg/kg s.c.) in different combinations: TOCP, TOCP + PMSF, PMSF + TOCP and PMSF. PFK activity was determined in brain and sciatic nerve 1, 3, 7 and 15 days after treatment. PFK activity decreased in sciatic nerve 15 days after dosing with TOCP or TOCP + PMSF. When animals were dosed with the protective agent (PMSF) alone or before administering the neurotoxic compound, PFK activity was unaltered and clinical signs of neuropathy were absent. The data presented here suggest that phosphofructokinase is involved in the pathogenesis of the neuropathy induced by TOCP.

Sudden cardiac death: a comparative study of morphological, histochemical and biochemical methods

The study deals with the comparison of morphological, histochemical and biochemical methods applied to the detection of myocardial infarction in 150 medico-legal autopsies performed at the Institute of Forensic Pathology in Copenhagen. The study also included an NBT (formazan) test of cardiac cross-sections, and light microscopy and fluorescence microscopy of acridine orange-stained specimens from four different sites of the cardiac musculature. Specimens of myocardium from the same four sites and pericardial fluid were analysed biochemically at the Institute of Legal Medicine in Granada. The K+/Na+ ratio was determined in the myocardial tissue and total creatine phosphokinase activity, creatine phosphokinase isoenzymes (MM, MB and BB) and myoglobin were assayed in pericardial fluid. When the results from Copenhagen and Granada were compared, there was absolute concordance in 96 cases, discrepancy in 53 and one case was inconclusive. After studying the circumstances of death, the number of discrepancies were reduced to 20, so that concordance was reached in 86% of all the cases. The results show that the combination of different methods leads to a diagnosis of myocardial infarction in far more cases than with morphological or biochemical methods alone.

A fatal case of oral ingestion of methanol. Distribution in postmortem tissues and fluids including pericardial fluid and vitreous humor

A 41-year-old man ingested orally a large quantity of methanol and was found dead at home. The presence of methanol in body fluids and tissues was determined by head-space gas chromatography. The blood ethanol and acetone were negative. Tissue distribution of methanol showed that the kidney presented the highest content of methanol (5.13 g/kg) followed by liver (4.18 g/kg), vitreous humor (3.96 g/l), heart (3.45 g/kg), urine (3.43 g/l), pericardial fluid (3.29 g/l), blood (2.84 g/l) and finally stomach content (2.21 g/l).

The usefulness of lung surfactant phospholipids (LSPs) in the diagnosis of drowning

The authors have studied the usefulness of some lung surfactant phospholipids (LSPs) isolated from lung tissues as markers of drowning. Two different groups of rabbits were sacrificed by drowning in fresh and salt water, and their phospholipid compositions were compared with those of a non-drowned control series. For the phospholipids studied in lung lavages (phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl glycerol) the proportions differed between the control group and the drowned group, and between the fresh-water and salt-water drowned animals. According to these results, the lipids we have analyzed can be employed as markers in forensic autopsies, where it is necessary to differentiate between death by drowning and postmortem immersion and between fresh-water and salt-water drowning. In lung tissue, only phosphatidyl choline and phosphatidyl inositol showed significative differences. These results also confirm that LSPs are strongly affected in drowning.

Poisoning by thallium. A study of five cases

Thallium poisoning seldom occurs in Spain. This article reports 5 cases of thallium poisoning, of which 4 of the patients belonged to the same family. The cases occurred in or near Granada between 1985 and 1987. The symptoms were initially gastrointestinal (vomiting, abdominal pain, gastrointestinal haemorrhage, etc.) in the case of the family poisoning, and a sensitive-motor polyneuritis in the fifth case. The diagnosis was established by analysis carried out in the authors' laboratory; urinary thallium concentrations were determined by atomic absorption spectrophotometry with graphite furnace and monovalent hollow cathode lamp. Each case was followed up to confirm the efficacy of the treatment; recovery from the poisoning was complete in all cases after 3 to 9 weeks.

[Significance of peroperative cholangiography in elective geriatric surgery of the bile ducts]

We present a retrospective study on the value of peroperative cholangiography (POC) in geriatric patients submitted to elective surgery of the biliary tract. We analyze the results of the present series and compare them with a previous study of 200 cases of cholelithiasis in the general population. Our conclusion is that in geriatric patients, POC should be a routine practice in order to avoid an unnecessary choledochotomy and/or residual lithiasis post-cholecystectomy.

Plasmatic levels of atrial natriuretic peptide (ANP) in drowning. A pilot study

Bodies found in water may cause problems for forensic pathologists who have to differentiate drowning from postmortem immersion or fresh from salt water drowning. The exact physiopathology of drowning is still controversial and complementary tests can not exactly establish the exact cause of death if macroscopic findings at autopsy are not conclusive. We have employed atrial natriuretic peptide (ANP) as a marker in an experimental series of fresh and salt water drowning, comparing their results with a non-drowned control series. There are differences between the plasma basal levels of the control series (79 pg/ml) and the levels in animals drowned in fresh water (358 pg/ml, P less than 0.001) and between control and rabbits drowned in salt water (190 pg/ml, P less than 0.001). According to these values, there are also differences between fresh and salt water drowned animals (P less than 0.001). We propose this peptide as a new marker in cases of drowning, with the ability to differentiate drowning from postmortem immersion and fresh from salt water drowning.