Frozen cadaver. Antemortem versus postmortem.

Three categories of skin from Hanford miniature swine were examined microscopically: normal, unfrozen skin; skin exposed to -75 degrees C air for 5 min, 6 h postinjury; and skin frozen postmortem. Frostbitten skin (antemortem freezing) was characterized grossly by a purple discoloration and microscopically by dilated, blood-filled, superficial capillaries. Other changes in the frostbitten skin were vacuolated epithelial cells and dermal edema. Unfrozen skin (controls) and skin frozen postmortem were more difficult to differentiate. However, the epidermis of the latter usually was compressed and more basophilic. We concluded that skin frozen antemortem could be separated from skin frozen postmortem by its intense hyperemia, characterized grossly as a purple discoloration and microscopically by engorged capillaries.     

The morphogenesis of electrically and heat-induced dermal changes in pig skin

In order to establish pathological evidence in dermis for distinguishing between sequelae of electrical torture and those of other superficial injuries, the skin of eleven fully anaesthetized Danish Landrace pigs have been exposed to heat and electrical energy from either 50 Hz alternating current (a.c.) or direct current (d.c.) via 12 mm large contact knobs or via a pointed 0.5 mm large electrode (only 50 Hz a.c.). The lesions have been examined from 1 to 126 days after the injury. While heat lesions exposed to energy lower than 60 joule only gave minor changes, heat lesions exposed to more than 60 joule showed changes in both collagen fibres (basophilic or eosinophilic fibres without any birefringence or coarse cross-striation in polarized light, respectively) and dermal cells (granular cytoplasm). Areas exposed to 50 Hz a.c. via 0.5 mm. electrode showed basophilic collagen fibres and in a few biopsies on day 7 calcium salts on collagen fibres. Using 12 mm large electrodes the changes were minor, but basophilic and eosinophilic collagen fibres with no birefringence or with fine/coarse cross-striation respectively were seen. Even cells with 'vesicular nuclei' were seen on day 1 and 2 after the injury. The changes in the anode area showed resemblance to that of heat lesions (basophilic collagen fibres). Eosinophilic collagen fibres with fine densely spaced cross-striation in polarized light and 'vesicular nuclei' as well as collagen fibres with calcium salts were seen in the cathode lesions. It is concluded that the dermal changes in the cathode area are specific for electrical injury from day 1 to 14. However, earlier studies have demonstrated dermal changes specific for electrical injury at day 0 and the presence of calcified collagen fibres up to 2 months after injury. The dermal changes in anode lesions were non specific and could not be differentiated from those found in heat lesions. Alternating current lesions (50 Hz) were specific from day 1 to day 7, when the pointed electrode was used, but only in a few days when the energy was transferred via the 12-mm electrodes.     

Excretion of alcohol in urine and diuresis in healthy men in relation to their age, the dose administered and the time after drinking

Healthy male volunteers drank neat whisky in amounts corresponding to 0.51, 0.68, or 0.85 g ethanol/kg body weight in 15-25 min after an overnight (10 h) fast. Urine was collected immediately before drinking and then at 60 min intervals for 7-8 h after intake. The volumes of urine voided were measured and the concentrations of alcohol (UAC) were determined by an enzymatic method. Ethanol-induced diuresis showed large inter-subject variations. The flow of urine was maximum between 60 and 120 min post-drinking when the median rates of production were 117 ml/h (range 55-335), 113 ml/h (range 41-453) and 373 ml/h (range 215-485) for 0.51, 0.68, and 0.85 g ethanol/kg respectively. The output of urine returned to normal (30-60 ml/h) after the peak UAC had passed despite an elevated blood alcohol concentration (BAC). The average amount of alcohol excreted in urine was 0.29 g (S.D. 0.119), 0.44 g (S.D. 0.246), and 1.00 g (S.D. 0.427) after the consumption of 0.51, 0.68 and 0.85 g ethanol/kg respectively. Neither peak diuresis nor the amount of alcohol excreted depended on a subject's age between 20 and 60 years. This work shows that after drinking a moderate dose of alcohol, only 0.7-1.5% of the amount consumed is excreted unchanged in urine. Ethanol-induced diuresis is most pronounced for the first 1-2 h after drinking (rising BAC). The production of urine returns to normal during the post-absorptive state.     

Identification of novel genes expressed in hypoxic brain condition by fluorescence differential display

Fluorescence differential display (FDD) and comparative RT-PCR have been used extensively to detect differentially expressed genes. We investigated hypoxia-induced gene expression in the brain by FDD-PCR and comparative RT-PCR. Mice were anaesthetized after which hypoxia was induced by neck ligation for 1 min or 25 min, then were killed by decapitation, and the brains were dissected either immediately or 30 min after death (Group A1-0, Group A25-0, Group A1-30 and Group A25-30). Control mice without ligation of the neck were killed by decapitation under anaesthesia immediately (Group C-0) or 30 min after death (Group C-30). FDD-PCR, sequence analysis and comparative RT-PCR revealed that mitochondrial thymidine kinase 2, Rab6, selenoprotein T and two novel cDNAs were enhanced in Group A25-0 and Group A25-30 compared with the other groups. In Group A25-30, only RAP2 interacting protein and another novel cDNA were induced. In Group A25-0, one novel gene was detected. These findings were consistent with the results of statistical analysis by ANOVA. No differences of band pattern were observed among Groups A1-0, A1-30, C-0 and C-30. The genes exhibiting altered expression were associated with vital cellular functions, e.g., intracellular signaling and mitochondrial metabolism. In addition, we identified four novel genes, expressed after extended hypoxic conditions in mouse brain with suffocation. These results may contribute to clarify the pathophysiology of asphyxia in the brain and aid in the diagnosis of suffocation.     

Image analysis of gunshot residue on entry wounds. I--The technique and preliminary study.

An automated image analysis (IA) technique has been developed to obtain a measure of the amount (i.e. number and area) of gunshot residue (GSR) particles within and around a gunshot wound. Sample preparation and IA procedures were standardised to improve the reproducibility of the IA measurements of GSR. Measurements of GSR from test firings into goat hide were enhanced by staining the barium and lead components present on the skin sections with Alizarin Red S. The amount of GSR detected on the stained skin sections was compared with backscatter electron micrographs of the same sections. The differences were deemed to be insignificant when the variability in the repeated test firings were taken into consideration. Preliminary results indicated that the decreasing relationship between firing range and the amount of GSR deposited was non-linear, and that for firing ranges of up to 20 cm the amount of GSR deposited from repeated shots fired from the same distance was highly variable.     

Image analysis of gunshot residue on entry wounds: II – A statistical estimation of firing range

A statistical investigation of the relationship between firing range and the amount and distribution of gunshot residue (GSR), used automated image analysis (IA) to quantify GSR deposit resulting from firings into pig skin, from distances ranging between contact and 45 cm. Overall, for a Ruger .22 semi-automatic rifle using CCI solid point, high velocity ammunition, the total area of GSR deposit on the skin sections decreased in a non-linear fashion with firing range. More specifically there were significant differences in the amount of GSR deposited from shots fired at contact compared with shots fired from distances between 2.5 and 45 cm; and between shots fired from a distance of 20 cm or less, with shots fired at a distance of 30 cm or more. In addition, GSR particles were heavily concentrated in the wound tract only for contact and close range shots at 2.5 cm, while the particle distribution was more uniform between the wound tract and the skin surfaces for shots fired from distances greater than 2.5 cm. Consequently, for future scientific investigations of gunshot fatalities, once standards have been established for the weapon and ammunition type in question, image analysis quantification of GSR deposited in and around the gunshot wound may be capable of providing a reliable, statistical basis for estimating firing range.     

Image analysis of gunshot residue on entry wounds. II--A statistical estimation of firing range.

A statistical investigation of the relationship between firing range and the amount and distribution of gunshot residue (GSR), used automated image analysis (IA) to quantify GSR deposit resulting from firings into pig skin, from distances ranging between contact and 45 cm. Overall, for a Ruger .22 semi-automatic rifle using CCI solid point, high velocity ammunition, the total area of GSR deposit on the skin sections decreased in a non-linear fashion with firing range. More specifically there were significant differences in the amount of GSR deposited from shots fired at contact compared with shots fired from distances between 2.5 and 45 cm; and between shots fired from a distance of 20 cm or less, with shots fired at a distance of 30 cm or more. In addition, GSR particles were heavily concentrated in the wound tract only for contact and close range shots at 2.5 cm, while the particle distribution was more uniform between the wound tract and the skin surfaces for shots fired from distances greater than 2.5 cm. Consequently, for future scientific investigations of gunshot fatalities, once standards have been established for the weapon and ammunition type in question, image analysis quantification of GSR deposited in and around the gunshot wound may be capable of providing a reliable, statistical basis for estimating firing range.     

Image analysis of gunshot residue on entry wounds: I – The technique and preliminary study

An automated image analysis (IA) technique has been developed to obtain a measure of the amount (i.e. number and area) of gunshot residue (GSR) particles within and around a gunshot wound. Sample preparation and IA procedures were standardised to improve the reproducibility of the IA measurements of GSR. Measurements of GSR from test firings into goat hide were enhanced by staining the barium and lead components present on the skin sections with Alizarin Red S. The amount of GSR detected on the stained skin sections was compared with backscatter electron micrographs of the same sections. The differences were deemed to be insignificant when the variability in the repeated test firings were taken into consideration. Preliminary results indicated that the decreasing relationship between firing range and the amount of GSR deposited was non-linear, and that for firing ranges of up to 20 cm the amount of GSR deposited from repeated shots fired from the same distance was highly variable.     

Localization and quantification of the nonspecific esterase in injured skin for timing of wounds.

Histochemical quantification of the nonspecific esterase (NSE) in injured skin was performed using histochemical demonstration of the enzyme and a microspectrophotometric scanning technique on specimens taken from 32 Hartley guinea-pigs and 8 cases of human skin wounds. In all antemortem incisions and lacerations, including those made at the agonal stage, NSE activity could be observed in the dermal tissue of the wound edge. The enzyme activity increases with the antemortem duration of the injuries. Both total content and mean concentration of NSE in the wound edge between antemortem and postmortem wound groups differ significantly (less than 0.01). Multiple range test shows that significant differences (P less than 0.05 or P less than 0.01) of total content of NSE in the wound edge also exist in 0-5 min, 15-30 min, 1-h, 2-h and 4-h antemortem incised wound groups and in 0-min, 5-min, 15-30 min, 1-h and 4-h antemortem laceration groups. The positive NSE reactions in 8 cases of human skin wounds were similar. The study indicates that histochemical quantification of NSE in injured skin is very useful in timing wounds and is exactly applicable in medicolegal practice. According to the different influences of inhibitors on enzymes, it was inferred that the enzyme activity in wound edges was due to B-esterase.     

Investigation of the short-time autolysis of rat hearts by means of SDS. Polyacrylamide gel electrophoresis and electron microscopy.

The short-time autolysis of hearts was regarded as a model of ischaemic heart failure. Therefore, isolated rat hearts were subjected to 30--120 min autolysis in a Locke solution at 37 degrees C. Electron microscopic examinations and myofibrillar preparations were made from the autolysed heart ventricles. The myofibrillar proteins were resolved by SDS-polyacrylamide gel electrophoresis. After 30 min autolysis the amount of a protein of 192,000 daltons greatly increased. At the same time on the electron micrographs the focal destruction of filament destruction on the A filament area and the mitochondrial structure altered too. After 60 min autolysis another protein of 36,400 daltons appeared. On the electron micrographs the focal desintegration of Z membranes and the focal destruction of I filaments can be observed. After 120 min autolysis further proteolytic products could not be detected by gel electrophoresis but on the electron micrographs the destruction of Z membranes and I filaments became more pronounced.     

The effect of sodium hydroxide and hydrochloric acid on pig dermis. A light microscopic study

In order to compare the dermal changes after exposure to direct current (d.c.) with changes after influence of acid and base influence, the skin of fully anaesthetized Danish Landrace pigs were exposed to acid and basic solutions. Biopsies were obtained immediately after and up to day 7 after the injury. Collagen fibres with increased affinity for eosin and irregular cross-striation in polarized light together with shrunken cells with dark stained nuclei were found just beneath the epidermis immediately after application of 1 N HCl. Immediately after exposure to 1 N NaOH dispersed collagen fibres showed increased eosinophilia and a fine densely spaced cross-striation in polarized light and vesicular nuclei were present within dermal cells. During the following days a narrow demarcation zone of neutrophilic granulocytes separated the zone containing abnormal collagen fibres from normal tissue below. Calcified collagen fibres were not observed and no other abnormal histochemical reactions were present. It is concluded that the morphology of acid induced lesions and base induced lesions shows resemblance to the morphology of anode and cathode lesions, respectively, but not to heat lesions. The reason for not finding depositions of calcium salts on collagen fibres in skin exposed to basic solutions could be a non-optimal pH in the tissue or that other electrochemical processes than shift in pH are necessary for the calcification process.     

Dermatoglyphic examination of the dermal surface of bodies in advanced postmortem condition

A new technique was applied to examine dermatoglyphic characteristics in dead bodies in advanced postmortem conditions. For this purpose, the volar skin was first fixed in formalin, incubated in 1 N potassium hydroxide solution, and then the dermis was exposed. Dermatoglyphic features were inspected on the dermal surface by staining with toluidine blue solution. This technique may be useful in cases in which the regular examination process does not provide favourable results because of advanced decomposition of the skin.     

应用SPME-GL／MS检测放火现场中助燃剂的研究

运用GC/MS拜利用自制的萃取、加热装置,研究在纵火现场助燃剂一汽油、煤油、柴油检测中固相微萃取的萃取温度和萃取时间对检测灵敏度的影响,确定了适于实际检案中采用的萃取时间和萃取温度.此法测定汽油、煤油、柴油的检出限分别为0.65 pl/ml、1.63pl/ml和1.63 pl/ml.     

Potential for error when assessing blood cyanide concentrations in fire victims.

The present study explores toxicologic significance of blood cyanide concentrations in fire victims. Headspace gas chromatography was used for cyanide detection. Analysis of blood samples from ten fire victims (postmortem interval = 8 h to 3 to 5 d) detected zero to 11.9 mg/L of cyanide and a large difference in cyanide concentrations among victims. Carboxyhemoglobin (COHb) saturation was in the range of 24.9 to 84.2%. To examine the effects of methemoglobinemia and postmortem interval on blood cyanide concentrations in fire victims, an experiment was carried out using rabbits as the animal model. The rabbits were sacrificed by intramuscular injection of 1 mL/kg 2% potassium cyanide 5 min after intravenous injection of 0.33 mL/kg of 3% sodium nitrite (Group A, n = 3) or physiological saline (Group B, n = 6). Average methemoglobin contents immediately before potassium cyanide administration were 6.9 and 0.8% in Groups A and B, respectively. Average cyanide concentrations in cardiac blood at the time of death were 47.4 and 3.56 mg/L, respectively. When blood-containing hearts of the rabbits (n = 3 for Group B) were left at 46 degrees C for the first 1 h, at 20 to 25 degrees C for the next 23 h and then at 4 degrees C for 48 h, approximately 85 and 46% of the original amounts of blood cyanide disappeared within 24 h in Groups A and B, respectively. After the 72-h storage period, 37 and 10%, respectively, of the original amounts of cyanide remained in the blood. When the other three hearts in Group B were left at 20 to 25 degrees C for the last 48 h without refrigeration, cyanide had disappeared almost completely by the end of the experiment. The present results and those published in the literature demonstrate that the toxic effects of cyanide on fire victims should not be evaluated based solely on the concentration in blood.     

Tissue distribution of lidocaine in critical care patients after intubation

We investigated tissue distribution of lidocaine in 33 patients after endotracheal intubation with Xylocaine jelly that contains 2% lidocaine hydrochloride. Blood levels of monoethylglycinexylidide (MEGX), an active metabolite of lidocaine, were also determined. Five patients (Group A) were alive on arrival and six patients (Group B) resumed heartbeats after cardiopulmonary resuscitation (CPR). The survival times for Groups A and B ranged from 3 to 72 h. The remaining 22 patients (Group C) did not survive cardiopulmonary arrest on arrival (CPAOA). Systemic distribution of lidocaine was measured in nine patients from Group C. The liver-to-kidney lidocaine ratios and cerebrum-to-cerebrospinal fluid lidocaine ratios were: Group A, 0.1-0.7 and 1.4-3.6, respectively; Group B, 0.2-0.8 and 1.2-2.3, respectively; Group C, 0.1-17 and 0.2-1.0, respectively. MEGX was detected in all blood samples from Group A and only two samples from Group B. No MEGX was detected in samples from Group C. Our results indicate that the absorption of tracheal lidocaine during natural circulation results in a cerebrum-to-cerebrospinal fluid lidocaine ratio of 1.2 or more, whereas absorption during artificial circulation by cardiac massage gives a ratio of 1.0 or less. The cerebrum-to-cerebrospinal fluid lidocaine ratio may be a more useful index to estimate circulatory dynamics of patients during CPR than the liver-to-kidney lidocaine ratio. MEGX was not a useful parameter for monitoring circulatory changes during cardiac massage.     

小鼠皮肤切创后不同时间的Tenascin免疫组化染色变化

目的探讨小鼠皮肤切创愈合过程中Tenascin表达变化及其与损伤时间的关系。方法制作小鼠背部全层皮肤切创模型,于伤后1、3、6、12h,1、3、6、9、12d分别观察切创周围皮肤、创缘皮肤及创腔肉芽组织的Tenascin免疫组化染色反应,并用图像分析技术检测Tenascin阳性染色的平均光密度,所得数据用SPSS for Windows 10.0软件包进行统计学分析。对照用无切创皮肤。结果对照组仅见真皮乳头、毛囊免疫组化染色弱阳性反应;伤后3h在切创周围的真皮乳头及毛囊Tenascin阳性染色增加;伤后12h明显增强,1~3d达最大值(0.336±0.061;0.282±0.017);伤后6d染色强度开始减弱,9~12d基本恢复正常。创缘皮肤及创腔肉芽组织伤后3~6h开始出现Tenascin阳性着色,12h明显增强,6d达最大值(0.410±0.051;0.460±0.027);伤后9d阳性着色开始减弱,12d基本恢复正常。结论小鼠皮肤切创愈合过程中产生的Tenascin随损伤时间呈现一定的规律性变化。     

人体皮肤创伤组织细胞因子表达的时间相关性

目的探讨TGF-β1、b—FGF和VEGF在人体皮肤创伤组织中的表达变化及其与损伤时间的关系。方法收集15例机械性致伤的人体皮肤组织(受伤5—120min内死亡),常规制作组织切片后进行免疫组化染色,并统计分析TGF-β1、b—FGF和VEGF因子的表达情况。结果 TGF-β1在16—50min组表达升高,60～120min组呈阳性至强阳性表达;b—FGF在16—50min组表达升高明显,强阳性表达亦出现在60～120min组;VEGF仅在60—120min组出现阳性表达。统计学分析表明,TGF—β1和b—FGF的表达升高分别在受伤60~120min(P<0.01)和在16—50min(P<0.01)有显著性意义,VEGF表达升高只在60~120min(P<0.05)有显著性意义。结论 TGF-β1、b—FGF和VEGF的表达时间和表达强度与损伤时间有关;TGF-β1、b—FGF和VEGF的表达可为人体短存活期损伤时间的推断提供参考。     

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)     

Comparison of pulmonary autopsy findings of the rats drowned at surface and 50 ft depth

INTRODUCTION: When a body is recovered from the water after a fatal SCUBA diving accident, it is useful to know if the diver was under pressure or not when he/she took his/her last breath, in order to determine the cause and manner of the death. If the victim was under pressure, the air remained in the lungs of the diver will be equal to the environmental pressure. If the body comes to the surface, the air in the lung will expand according to the Boyle's Gas Law and give mechanical damage to the surrounding tissues, due to decreases in environmental pressure. We designed an experimental study to see the difference in pulmonary autopsy findings of the rats that drowned under normobaric and hyperbaric conditions. METHOD: Forty five male, 250-300 g, Sprague Downey adult rats were divided into three groups. Two groups of rats were drowned under normobaric conditions (Groups DS Group DSS) and the third group at 50 ft pressure (Group DD). The pulmonary autopsy findings of the groups were compared. In the light microscopy, the number of the microscopic fields (x10) containing at least one emphysematous area with longitudinal dimension greater than 300 micro m were compared among the groups. RESULTS: The gross examination revealed a prominent swelling of the lungs in all rats in the Group DD, in comparison to that of the Groups DS and DSS. The number of the microscopic fields, which included at least one emphysematous area with longitudinal dimension greater than 300 micro m out of 150 fields from each of the groups DS, DSS and DD, were 88, 101 and 115 respectively. The difference between the group DS and DD was found to be statistically significant. CONCLUSION: We conclude that in investigating the fatal diving accidents, pulmonary autopsy findings give valuable information whether the death occurred at the surface or at the depth.     

Dermal lesions after post mortem petrol-exposure

The effect of post mortem contact of the skin with petrol was investigated in 18 corpses with exposure times between 10 min and 24 h. The earliest onset of skin changes was observed within 2 h of exposure. They consisted of swelling and wrinkling with detachment of the upper layers of the skin (positive Nikolski's sign). Histologically the lesions appeared as non-vital acantholyses located in the prickle-cell layer with formation of intra-epidermal bullae. An influence of age and sex could be excluded, the earlier onset of lesions at 22 degrees C than at 4 degrees C was not statistically significant. These findings prove that post mortem petrol exposure may lead to dermal lesions.