Marine bacteria comprise a possible indicator of drowning in seawater

To investigate the effectiveness of marine bacteria as a new marker of drowning in seawater, we determined the optimal conditions of media required to selectively detect marine bacteria and applied the technique to drowned cadavers. We incubated model blood samples (n=20 per group) mixed with seawater, river, tap or muddy water on agar plates (Todd Hewitt, TH; Marine 2216, M2216) and determined the NaCl concentration required to selectively detect marine bacteria. We also used TCBS agar plates without manipulation to isolate Vibrio spp. Among the culture media, TH agar was superior. Bioluminescent colonies were detected only in blood mixed with seawater. Blue colonies stained using the cytochrome oxidase test (COT), were detected in blood mixed with both sea and river water. However when the NaCl concentration was above 4%, COT stained colonies were detectable only in blood mixed with seawater. We subsequently used 2, 3 and 4% NaCl in TH and TCBS agar to examine blood from victims who had drowned in seawater (n=8) and in fresh water (n=7), as well as from victims who died near aquatic environments (non drowned; dry-land control, n=7). Bioluminescent colonies were detectable on 2-4% NaCl TH agar only from two victims that drowned in seawater. Bioluminescent colonies did not grow on TCBS agar. Blue colonies from all cadavers that had drowned in seawater (8/8) and in four of those that had drowned in fresh water (4/7) proliferated on TH agar containing 2% and/or 3% NaCl, but at 4% NaCl such colonies were detected only from cadavers that had drowned in seawater (8/8). Colonies from only one cadaver from seawater grew on TCBS agar. Furthermore, neither bioluminescent nor blue colonies were detected on TH agar containing 4% NaCl in samples from two cadavers found in an estuary (brackish water) who were thought to have been carried from areas of fresh water. Homologous analyses of the 16S rRNA gene revealed that the dominant colonies on TH agar containing 4% NaCl were marine bacteria (Photobacterium, Vibrio, Shewanella, Psychrobacter). Thus, proliferating bioluminescent and/or blue colonies detected in the blood of immersed cadavers using 4% NaCl TH agar, could help to establish drowning in seawater.     

Failure to detect elevated levels of carboxyhemoglobin in infants dying from SIDS

Carboxyhemoglobin (COHb) levels were determined in stored blood samples from 91 infants diagnosed to have died from the sudden infant death syndrome (SIDS) (0.59+/-0.41%, excluding one outlying value of 10.83%); 48 age-matched controls (0.53+/-0.38%); and three individuals who died from fire related causes (41+/-20%). No statistical differences in COHb levels were detected between blood from SIDS and control infants (p = 0.43).     

A sandwich enzyme immunoassay for pulmonary surfactant protein D and measurement of its blood levels in drowning victims

A sensitive sandwich enzyme immunoassay for human pulmonary surfactant protein D (SP-D) was developed and used to examine the blood SP-D levels of drowning victims. Human SP-D was purified from amniotic fluid by chromatographic methods, and an antibody against human SP-D was prepared. A polystyrene ball coated with anti-SP-D IgG was incubated with purified human SP-D, and then with anti-SP-D Fab'-peroxidase conjugate. Peroxidase activity bound to the polystyrene ball was assayed by fluorometry using 3-(4-hydroxyphenyl)propionic acid as the hydrogen donor. The detection limit of human SP-D was 5.2 pg per assay tube. Examination of cross-reactions of this sandwich enzyme immunoassay with proteins from other human organs showed it to be highly specific for lung, and Northern blot analysis detected specific SP-D mRNA expression only in lung. The SP-D concentration of normal human serum was 6.4+/-2.7 (mean+/-S.D.) ng ml(-1) (n=20). The recovery rates of 0.52 ng and 5.2 ng SP-D added to 5 microl normal human serum were 93.6+/-2.7% and 93.6+/-6.1%, respectively. Blood SP-D levels of victims from the saltwater drowning group (n=14) revealed higher concentrations (105.8+/-53.7 ng ml(-1)), while freshwater drowning victims (n=12) were estimated to be 74.1+/-43.9 ng ml(-1). The SP-D levels of 15 subjects who died of hemorrhage (n=5), heart failure (n=8), traumatic shock (n=1), and electrocution (n=1) were lower (22.0+/-8.5 ng ml(-1)), and those of asphyxia victims (n=10) were slightly higher (36.2+/-17.1 ng ml(-1)) than those of other causes of death, except for drowning. These results suggest that in drowning victims, SP-D flowed into the systemic circulation by physiological and physical mechanisms, and the differences of blood SP-D levels between saltwater drowning and freshwater drowning victims are presumed to be influenced by the type of agony and/or the length of survival time in water.     

血清IgE在药物过敏性休克死亡鉴定中的价值

目的 探讨血清IgE在药物过敏性休克死亡鉴定中的应用价值。方法 采用MEIA法，对17例明确鉴定为药物过敏性休克死亡者(休克组)和16例交通事故死亡者(对照组)的心血进行IgE检测，并对2组IgE检测结果进行统计学分析。结果 休克组IgE水平为(622.49±594.67)U／ml，对照组为(45.04±43.62)U／ml；经t检验，2组显著差异(P＜0.01)。结论 血清IgE水平升高，可作为鉴定药物过敏性休克死亡的依据之一。     

Experimental studies on death by fire in automobiles and exhaust gas poisoning

Studies were made on the acid-base balance, blood gases, and carbon monoxide (CO), cyanide, and sulfur dioxide concentrations in the blood of albino rabbits that died from automobile exhaust gas poisoning (group I) or fires in cars (complete combustion, group II; incomplete combustion, group III). In group I, the temperature and CO concentration increased gradually to 35 degrees C and 5.2% in 70 min. The animals died after 9 min, when the values were 20 degrees C and 5.2%, respectively. In group II the animals died after 9 min, when the values were 55 degrees C and 1.95%, respectively. In group III, the temperature was very high (870 degrees C), but the CO concentration was not (0.6-1.3%) after 4 min. The animals died after 5 min. In all experimental groups, marked acidosis and hypoxemia were seen, but the CO2 tension (PCO2) was high, in contrast to previous studies on pure CO poisoning. In group I, the level of carboxyhemoglobin (CO-Hb) was significantly higher (91.2 +/- 3.4% in arterial blood, 87.5 +/- 8.1% in venous blood; p less than 0.01) than in groups II and III. Although the O2 tensions of venous and arterial blood (PvO2, PaO2) were very low, that of arterial blood was higher, suggesting that O2 was still being utilized in the tissues at the time of death. In group II, CO-Hb was high (57.7 +/- 16.0% in arterial blood, 61.2 +/- 20.6% in venous blood) and the acid-base balance indicated marked acidosis. In group III, the CO-Hb, PCO2 and cyanide levels in the blood were very high.(ABSTRACT TRUNCATED AT 250 WORDS)     

Paraquat (gramoxone) poisoning in south-west Hungary, 1977-1984. Toxicological and histopathological aspects of group intoxication cases

Fifty-six cases of paraquat poisoning were examined during the 8 years 1977-1984. The ratio of cases of accidental to intentional ingestion of the poison was 1:1; 23.2% of the total (13/56) survived several months or years. In 1983, 11 subjects accidentally drank 10-30 ml of gramoxone; eight of 11 died in 2 weeks. Toxicological investigations demonstrated rapid elimination of poison from the blood, as well as prolonged fixation of paraquat in the lung, kidney, liver, and spleen tissues. Histological examinations showed multiorgan failure from renal tubular necrosis and pulmonary hemorrhage with alveolar epithelial injury. Pulmonary proliferative changes were present in only two cases who survived 7 and 10 days and in which artificial ventilation was utilized.     

Cytokinetics of epidermic cells in skin from human cadavers. II. Dependency on sex, age, and site

Kinetic data on the labeling index (LI), DNA synthesis time (ts), and potential doubling time (tpot) of epidermic cells in relation to sex, age, and site were obtained by in vitro incubation of skin cylinders from 45 human cadavers with DNA precursors 3H- and 14C-thymidine. In a first study on parts of the same material, it was established that LI over a period of more than 70 h and tpot over a period of at least 30 h remained essentially unchanged and are comparable with live humans, when the cadavers were stored at 4 degrees C. The following results were obtained: The female and male cadavers had a LI of 2.6% (+/- 0.8%) or 2.5% (+/- 0.8%), a ts of 3.9 h (+/- 0.2 h) or 5.0 h (+/- 1.6 h), and a tpot of 168.5 h (+/- 34.3 h) or 183.9 h (+/- 27.2 h). The LI for the thigh and knee ranged between 21.3% and 25.8% in different age groups. No statistically relevant differences were established between the sexes or among the age groups. Topographic allocation of the proliferative-kinetic data ultimately showed that, on the average, LI was relatively high at the elbow (3.1% +/- 1.0%) with short tpot (109.3 +/- 72.5 h) and a comparatively large epidermal diameter (47.1 microns); by contrast, LI at the lower abdomen was impressively low (2.1% +/- 0.8%), tpot relatively long (183.0 +/- 138.7 h) and mean epidermal diameter relatively small (23.0 microns). Nevertheless, no statistically relevant differences were established between data for elbow and lower abdomen or between other data for different sites. The proliferative-kinetic data for human cadavers were compared with data reported in the literature for live humans.     

Comparison of ethanol concentrations in venous blood and end-expired breath during a controlled drinking study

Concentration-time profiles of ethanol were determined for venous whole blood and end-expired breath during a controlled drinking experiment in which healthy men (n=9) and women (n=9) drank 0.40-0.65 g ethanol per kg body weight in 20-30 min. Specimens of blood and breath were obtained for analysis of ethanol starting at 50-60 min post-dosing and then every 30-60 min for 3-6 h. This protocol furnished 130 blood-breath pairs for statistical evaluation. Blood-ethanol concentration (BAC, mg/g) was determined by headspace gas chromatography and breath-ethanol concentration (BrAC, mg/2l) was determined with a quantitative infrared analyzer (Intoxilyzer 5000S), which is the instrument currently used in Sweden for legal purposes. In 18 instances the Intoxilyzer 5000S gave readings of 0.00 mg/2l whereas the actual BAC was 0.08 mg/g on average (range 0.04-0.15 mg/g). The remaining 112 blood- and breath-alcohol measurements were highly correlated (r=0.97) and the regression relationship was BAC=0.10+0.91BrAC and the residual standard deviation (S.D.) was 0.042 mg/g (8.4%). The slope (0.91+/-0.0217) differed significantly from unity being 9% low and the intercept (0.10+/-0.0101) deviated from zero (t=10.2, P<0.001), indicating the presence of both proportional and constant bias, respectively. The mean bias (BAC - BrAC) was 0.068 mg/g and the 95% limits of agreement were -0.021 and 0.156 mg/g. The average BAC/BrAC ratio was 2448+/-540 (+/-S.D.) with a median of 2351 and 2.5th and 97.5th percentiles of 1836 and 4082. We found no significant gender-related differences in BAC/BrAC ratios, being 2553+/-576 for men and 2417+/-494 for women (t=1.34, P>0.05). The mean rate of ethanol disappearance from blood was 0.157+/-0.021 mg/(g per hour), which was very close to the elimination rate from breath of 0.161+/-0.021 mg/(2l per hour) (P>0.05). Breath-test results obtained with Intoxilyzer 5000S (mg/2l) were generally less than the coexisting concentrations of ethanol in venous blood (mg/g), which gives an advantage to the suspect who provides breath compared with blood in cases close to a threshold alcohol limit.     

Two fatal intoxication cases with imidacloprid: LC/MS analysis

Imidacloprid [1-(6-chloro-3pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] is a new and potent nitromethylene insecticide with high insecticidal activity at very low application rates. It is the first highly effective insecticide that, like nicotine, acts on the nervous system, causing blockage of postsynaptic nicotinergic acetylcholine receptors. Two fatal cases with this insecticide in two male individuals, of 33 and 66 years old, are presented. An LC/MS with electrospray method for measuring imidacloprid and its metabolites in post-mortem samples is described. In the chromatographic separation, a reverse-phase column XTerra MS C18 (2.1mm i.d.x 150 mm, 5 microm) was used and the mobile phase composed with acetonitrile and 0.1% formic acid (15:85), at a 0.25 mL/min flow rate. Samples were prepared with a liquid-liquid extraction procedure with dichloromethane. Calibration curves for imidacloprid in blood and urine samples were linear from 0.2 to 15 microg/mL. The mean recovery was 86% with a coefficient of variation of +/-5.9%. The detection limit was 0.002 microg/mL. Quantitative results were obtained for all post-mortem matrices available of the two fatal cases: blood, urine, stomach contents, lung, liver and kidney. The imidacloprid blood concentrations found in two-cases were 12.5 and 2.05 microg/mL. The authors validated a method to detect and quantify imidacloprid in post-mortem samples, and to our knowledge for the first time a post-mortem tissue distribution was performed on various samples for this insecticide.     

Evaluation of breath-alcohol instruments. III. Controlled field trial with Alcolmeter pocket model

A breath-alcohol screening device, Alcolmeter pocket model, was evaluated in a controlled field trial with policeman operating the instruments. The results of tests made with subjects before they drank alcohol were always zero. The standard deviation (S.D.) of breath alcohol determinations increased with increase in the concentration of alcohol in the sample, being 0.036 mg/ml at a mean blood-ethanol concentration of 0.53 mg/ml. The S.D. varied among subjects tested (from 0.022 to 0.053 mg/ml) as well as among the instruments used (from 0.023 to 0.054 mg/ml). The breath test results were on average less than the actual blood-ethanol concentrations when a 2100: 1 blood/breath ratio was used to calibrate the Alcolmeter device. Blood ethanol (x) and Alcolmeter readings (y) were highly correlated (r = 0.95 +/- 0.018) and the regression equation was y = -0.017 + 0.95x. At a mean blood-ethanol concentration of 0.50 mg/ml, the Alcolmeter instrument will indicate 0.46 mg/ml on average. The standard error estimate was 0.085 mg/ml, being 17% of the mean Alcolmeter reading and this corresponds to 95% confidence limits of +/- 0.17 mg/ml. The results of this study show that Alcolmeter pocket-model is a useful device for breath-alcohol screening purposes at a blood-alcohol level of 0.50 mg/ml. A blood/breath ratio of 2300 should be used to calibrate the Alcolmeter device.     

Fatal and non-fatal methomyl intoxication in an attempted double suicide

A 79-year-old man and his 73-year-old wife attempted double suicide by ingesting methomyl powder. The woman died 19 h after ingestion in spite of intensive care. At autopsy a large number of miliary hemorrhages were found in both thalami of the brain. Her husband, however, recovered after 10 days of treatment. Methomyl (CAS No. 16752-77-5, Lannate) in the biological materials was analyzed by gas chromatography-mass spectrometry. The methomyl concentration was 44 micrograms/g in the wife's serum sample collected 1 h after ingestion, and 0.2 microgram/g in the blood sample collected at autopsy. The methomyl concentration in the husband's blood sample collected 28 h after ingestion was from 0.01 to 0.1 microgram/g. It is suggested that prompt and adequate intensive care including a direct hemoperfusion is necessary to effect the recovery of patients with lethal blood levels of methomyl. The miliary hemorrhages found in the thalami of the brain are suspected to have been caused by asphyxia induced by methomyl intoxication.     

Nicotine and cotinine levels in body fluids of smokers who committed suicide

Cigarette smoking is associated with a higher risk for suicide. The present study was conducted on the hypothesis that suicide smokers show higher nicotine and cotinine levels in blood and urine than non-suicide smokers. We determined nicotine and cotinine levels in blood and urine of 87 deceased individuals (18 suicides and 69 non-suicides) by gas chromatography. The smoking rate was 77.8% for individuals who committed suicide and 42.0% for those who did not commit suicide. Average nicotine and cotinine levels in blood were significantly higher in the suicide smokers than in the non-suicide smokers (nicotine: 93.2+/-46.6 ng/ml versus 25.8+/-14.4 ng/ml, p<0.0001 and cotinine: 378+/-235 ng/ml versus 201+/-137 ng/ml, p<0.005). Average levels of urinary nicotine and cotinine were also significantly higher in the suicide smokers than in the non-suicide smokers (nicotine: 1980+/-2210 ng/ml versus 394+/-376 ng/ml, p<0.005 and cotinine: 1170+/-1330 ng/ml versus 414+/-290 ng/ml, p<0.05). Twenty-six decedents were intoxicated with alcohol, and they included 7 suicides (7 smokers) and 19 non-suicides (15 smokers). Our data suggest that cigarette smokers who commit suicide smoke more heavily than other cigarette smokers.     

Vital reactions in Pacchioni granulations

By means of histological methods the authors examined the blood and fluid circulatory disturbances associated with cranial and cerebral injuries. The presence of vital reactions was studied by means of the combined histological study of the dura mater, pacchionian granulations and the central nervous system. Samples for histological study were taken from 115 cadavers who had suffered cranial injuries, from 15 individuals who died from destructive cerebral apoplexy caused by a disease and from 30 individuals who died of natural causes. The authors applied a special fixation and sampling technique and, using various histological reactions, the following vital reactions were observed: the appearance of blood-cell elements in the granulation, a moderate fibrin degradation product and hemoglobin phagocytosis, and occasionally lipid phagocytosis. The authors worked out a method that was shown to be highly effective in the more precise determination of the induction time of cerebral apoplexy caused by a disease and that of traumatic injury of the brain.     

Evaluation of breath-alcohol instruments. IV. Roadside tests with Alcolmeter pocket model

This paper reports results from a field trial with a breath-alcohol screening device--Alcolmeter pocket model. Breath tests were made with drivers apprehended during routine controls (road-blocks), for traffic violations and those involved in traffic accidents. Of 908 roadside breath tests made with chemical reagent tubes, 343 showed zero alcohol (no colour change) and these results were confirmed by Alcolmeter. Alcohol was detected in 191 tests but the level was judged as being below the legal limit of 0.50 mg/ml. The Alcolmeter results, however, ranged from 0 to 1.22 mg/ml (mean 0.21 mg/ml) and 15 individuals (7.8%) were above the legal limit. There were 373 positive chemical tube breath screening tests whereas in 5 cases (1.3%) Alcolmeter indicated a blood-alcohol level below 0.50 mg/ml. Duplicate determinations with the Alcolmeter device were highly correlated r = 0.93 +/- 0.02 (+/- S.E.), P less than 0.001. The standard deviation of a single breath-alcohol analysis under field conditions was +/- 0.10 mg/ml which corresponds to a coefficient of variation of 10%. The time interval between positive roadside breath test and blood-sampling ranged from 5 to 220 min (median 62 min). The results were therefore adjusted by 0.15 mg/ml per hour to compensate for ethanol metabolised between the time of sampling blood and breath. The corrected blood and breath values were well correlated r = 0.84 +/- 0.03, P less than 0.001 but the predictive power of the regression relationship was poor. The regression equation was y = 0.27 +/- 0.65x and the standard error estimate was +/- 0.21 mg/ml at the mean concentration of ethanol of 1.0 mg/ml.     

Breath alcohol concentration determined with a new analyzer using free exhalation predicts almost precisely the arterial blood alcohol concentration

A new breath alcohol (ethanol) analyzer has been developed, which allows free exhalation, standardizes measured exhaled alcohol concentration to fully saturated water vapor at a body temperature of 37 degrees C (43.95 mg/L) and includes a built-in self-calibration system. We evaluated the performance of this instrument by comparing standardized alcohol concentration in freely expired breath (BrAC) with arterial (ABAC) and venous (VBAC) blood alcohol concentrations in fifteen healthy volunteers who drank 0.6 g of alcohol per kg body weight. The precision (coefficient of variation, CV) of the analyzer based on in vivo duplicate measurements in all phases of the alcohol metabolism was 1.7%. The ABAC/BrAC ratio was 2251+/-46 (mean+/-S.D.) in the post-absorptive phase and the mean bias between ABAC and BrAC x 2251 was 0.0035 g/L with 95% limits of agreement of 0.033 and -0.026. The ABAC and BrAC x 2251 were highly correlated (r=0.998, p<0.001) and the regression relationship was ABAC = 0.00045 + 1.0069 x (BrAC x 2251) indicating excellent agreement and no fixed or proportional bias. In the absorption phase, ABAC exceeded BrAC x 2251 by at most 0.04+/-0.03 g/L when tests were made at 10 min post-dosing (p<0.05). The VBAC/BrAC ratio never stabilized and varied continuously between 1834 and 3259. There was a proportional bias between VBAC and BrAC x 2251 (ABAC) in the post-absorptive phase (p<0.001). The pharmacokinetic analysis of the elimination rates of alcohol and times to zero BAC confirmed that BrAC x 2251 and ABAC agreed very well with each other, but not with VBAC (p<0.001). We conclude that this new breath analyzer using free exhalation has a high precision for in vivo testing. The BrAC reflects very accurately ABAC in the post-absorption phase and substantially well in the absorption phase and thereby reflects the concentration of alcohol reaching the brain. Our findings highlight the magnitude of arterio-venous differences in alcohol concentration and support the use of breath alcohol analyzers as a stand-alone test for medical and legal purposes.     

Ballistic skin simulant

Hydrogels prepared from water solutions containing 10-20 mass% gelatine are generally accepted muscle tissue simulants in terminal ballistic research. They, however, do not have a surface layer which simulates the effect of human skin. The purpose of this research was to find a suitable skin simulant for enhancing the testing fidelity and the credibility of the results with gelatine-based materials when assessing the injury potential of not only high energy bullets, but also especially that of non-penetrating "less lethal" kinetic impact ammunition and relatively low energy ricochet fragments. A skin simulant also permits the simulation and assessment of exit wounds. The mechanical and ballistic properties of human skin and target simulant were established on the basis of results found in the literature. Some errors in these were found. The corrected values are included in this paper for comparison. The target values of the mechanical properties of the skin simulant were the following: threshold velocity v(th)=94+/-4 m/s, tensile strength 18+/-2 N/mm2 and elongation at break 65+/-5%. A selection of synthetic and natural materials was evaluated as skin simulants by analysing their mechanical and ballistic properties. The results were compared to literature values obtained with human cadavers. The tests showed that the best skin simulant of the ones evaluated was semi-finished chrome tanned upholstery "crust" cowhide of 0.9-1.1 mm nominal thickness. Its threshold velocity was 90.7 m/s, tensile strength 20.89+/-4.11 MPa and elongation at break 61+/-9%. These values are the same as the average values of human skin. Of the synthetic materials evaluated, 1mm thick natural rubber can be used on impact side as a threshold velocity filter with some reservations although its theoretical threshold velocity is only 82.9 m/s.     

Death scene gas analysis in suspected methane asphyxia.

Two cases of methane asphyxia occurring in two boys (age 11 and 12 years) who were found at the bottom of a 37-ft (11.1-m)-deep sewer shaft are described. Attempted resuscitation of the first patient was unsuccessful and achieved only temporary stabilization of the second, who died 48 h after his discovery. Autopsies revealed relatively minor multifocal traumatic injuries, with evidence of hypoxic-ischemic encephalopathy in the patient who survived for 2 days. Subsequent analysis of gas in the shaft revealed 21% oxygen at the surface, 14.3% at a depth of 5 ft (1.5 m), and only 4.8% at depths of 10 ft (3 m) and below. Other gases detected at the lower levels were methane, nitrogen, and carbon dioxide (4.3%). These cases demonstrate the value of atmospheric gas analysis in cases of possible methane asphyxia in confirming the presence of methane and in demonstrating levels of oxygen below that necessary to support life.     

Relationship between the concentration of ethanol and methanol in blood samples from Swedish drinking drivers

Headspace gas chromatography was used to determine the concentration of ethanol and methanol in blood samples from 519 individuals suspected of drinking and driving in Sweden where the legal alcohol limit is 0.50 mg/g in whole blood (11 mmol/l). The concentration of ethanol in blood ranged from 0.01 to 3.52 mg/g with a mean of 1.83 +/- 0.82 mg/g (+/- S.D.). The frequency distribution was symmetrical about the mean but deviated from normality. A plot of the same data on normal probability paper indicated that it might be composed of two subpopulations (bimodal). The concentration of methanol in the same blood specimens ranged from 1 to 23 mg/l with a mean of 7.3 +/- 3.6 mg/l (+/- S.D.) and this distribution was markedly skew (+). The concentration of ethanol (x) and methanol (y) were positively correlated (r = 0.47, P less than 0.001) and implies that 22% (r2) of the variance in blood-methanol can be attributed to its linear regression on blood-ethanol. The regression equation was y = 3.6 + 2.1 x and the standard error estimate was 0.32 mg/l. This large scatter precludes making reliable estimates of blood-methanol concentration from measurements of blood-ethanol concentration and the regression equation. But higher blood-methanol concentrations are definitely associated with higher blood-ethanol in this sample of Swedish drinking drivers. Frequent exposure to methanol and its toxic products of metabolism, formaldehyde and formic acid, might constitute an additional health risk associated with heavy drinking in predisposed individuals. The determination of methanol in blood of drinking drivers in addition to ethanol could indicate long-standing ethanol intoxication and therefore potential problem drinkers or alcoholics.     

Selenium determination in mother and child's hair by electrothermal atomic absorption spectrometry

A method for the selenium determination in a mother and her child's hair using palladium as a chemical modifier was optimized. The sample was digested with nitric acid and hydrogen peroxide and diluted to 5 ml. To achieve complete mineralization the samples were ashed at 1200 degrees C in the presence of palladium as a chemical modifier. The optimum atomization temperature was 1900 degrees C. The precision and accuracy of the method were studied using the reference material CRM 397. Results of calibration using aqueous standards and the standard addition method were compared. The method was applied to the selenium determination in 30 samples of the mother's and child's hair. The levels found were 0.54 +/- 0.34 microgram/g for mother's hair and 0.77 +/- 0.25 microgram/g for child's hair.     

Post-mortem analysis of formic acid disposition in acute methanol intoxication

Fifteen cases of fatal massive methanol intoxication have been investigated. Victims received either no treatment or ethanol therapeutic treatment. Methanol poisoning cases were classified in three groups according to survival time: more than 3 days (group 1), up to 3 days (group 2) and few hours (group 3). Body distribution of methanol and formic acid, as the main metabolite, was analyzed in blood and in different organs (brain, kidney, lung and liver). Relationships between formic acid concentration in the different tissues, survival time and type of treatment applied to victims were studied. Formic acid in blood and tissues was analyzed by head space gas chromatography (head space-GC) with FID detector, previous transformation in methyl formate, essentially as described by Abolin. Formic acid concentration was between 0.03 and 1.10g/l in the samples under study. A good correlation between blood and brain, but poor between blood and the remaining tissues was found. Obtained data suggested that the use of blood and brain could help to improve the analysis of formic acid intoxication. The best correlation among organs was found between lung and kidney for all groups (r(2)=0.91, 0.84 and 0.87, corresponding to groups 1, 2 and 3, respectively). Lethality index was defined as LI = (concentration of formic acid in blood in (g/l)/0.5) x 100, taking into account that 0.5g/l is the concentration reported by Mahieu in severe methanol poisoning. LI parameter was used to estimate formic acid incidence on the lethality of methanol poisoning cases. LI showed a good correlation with total formic acid concentration of the different tissues analyzed (r(2)=0.80). Furthermore, LI allowed us to discriminate between individuals that received therapeutic treatment and survived different periods. LI>100 indicated a severe intoxication and short survival time if the victim was assisted with ethanol therapy and hemodialysis was not applied. With regard to victims who received no therapeutic treatment and died in few hours, LI was in the range 40-100. LI was below 40 for individuals that survived more than 3 days and hemodialysis was not performed. Results showed the importance of performing formic acid analysis to diagnose severe methanol intoxication in post-mortem cases.