缢死大鼠肝肾细胞内HIF-1α免疫组化染色观察

目的探讨缺氧诱导因子1α(HIF-1α)在窒息死亡鉴定中的意义。方法制作大鼠缢死后0、2、6、24h的窒息死模型,以相应时间段断颈处死大鼠为对照,用免疫组织化学ABC法结合图像分析观测肝和肾组织中的HIF-1α表达情况,并对其结果进行统计分析。结果除0h段外,HIF-1α免疫组化阳性染色可见于窒息组和对照组的各时段大鼠,主要位于肝细胞、肾近曲小管和远曲小管上皮细胞。死后6h内的肝组织HIF-1α免疫组化染色显示窒息组与对照组差别明显(P<0.05),24h后则无明显差别(P>0.05)。肾脏窒息组与对照组差别明显(P<0.05)。结论观测HIF-1α在死后6h内肝脏或24h内肾脏中的表达状态,对机械性窒息的鉴定有一定的法医学意义。     

家兔急性有机磷中毒死后玻璃体液化学成分的变化趋势

目的 探讨家兔急性有机磷中毒死后不同时间眼玻璃体液化学成分的变化。方法用5％敌百虫制作家兔急性有机磷中毒动物模型,在死后0～72h内不同时间点,采用留置微量重复取样法吸取眼玻璃体液,以全自动生化分析仪测量眼玻璃体液中钾、镁、磷、钙、钠、氯浓度的变化,统计数据进行二项式回归方程拟合分析。结果家兔急性有机磷中毒死后72h眼玻璃体液中钾、镁、磷随PMI延长而逐渐升高,舻分别为0．9818、0．9700、0．9458,与PMI相关性好,其中30h内镁的相关性更好;钙、钠随PMI延长呈降低趋势,砰分别为0．7124、0．7355,相关性较差;氯表现不稳定掣仅为0．0869。结论家兔急性有机磷中毒死后玻璃体液中钾、镁、磷、钙、钠等离子浓度随PMI延长而改变,72h内总体衡量,钾与PMI最具有相关关系。     

Determination of calcium and magnesium in postmortem human vitreous humor as a test to ascertain the cause and time of death

The concentrations of magnesium and total calcium human vitreous humors obtained postmortem was tested. In the groups of heart disease and asphyxia a correlation between the postmortem interval and calcium or magnesium concentrations was found. There was no correlation between postmortem interval and calcium respectively magnesium in the other causes of death. It seems possible that the analysis of vitreous humor may be useful in both diagnosis and determination of postmortem interval in the cases of heart death and asphyxia.     

A comparison of respiratory symptoms and inflammation in sudden infant death syndrome and in accidental or inflicted infant death

Upper respiratory infection and pulmonary inflammation are common in sudden infant death syndrome, but their role in the cause of death remains controversial. Controlled studies comparing clinical upper respiratory infection and inflammation in sudden infant death syndrome with sudden infant deaths caused by accidents and inflicted injuries (controls) are unavailable. Our aim was to compare respiratory inflammation and upper respiratory infection within 48 hours of death and postmortem culture results in these two groups. A retrospective analysis of upper respiratory infection and pathologic variables in the trachea and lung of 155 infants dying of sudden infant death syndrome and 33 control infants was undertaken. Upper respiratory infection was present in 39% of sudden infant death syndrome cases and 40% of control cases. Upper respiratory infection was more likely to have occurred in association with more severe lymphocytic interstitial pneumonitis when sudden infant death syndrome cases and control cases were combined ( P=.04). Proximal and distal tracheal lymphocytic infiltration was more severe in control cases than in sudden infant death syndrome cases ( P=.01 and.01, respectively). Lymphocytic infiltrations of the bronchi, bronchioles, and pulmonary interstitium were similar between groups. Bronchial associated lymphoid tissue was more prominent in control cases ( P=.04). Cultures were positive in 80% of sudden infant death syndrome cases, 78% of which were polymicrobial. Among control cases, 89% were positive, with 94% being polymicrobial. This study confirms that microscopic inflammatory infiltrates in sudden infant death syndrome are not lethal.     

Pulmonary macrophage counts in deceased infants: baseline data for further study of infant mortality

Infant lung samples were obtained prospectively at autopsy by medical examiner pathologists in five areas of the United States and regardless of the cause of death. Four sections were examined for each case and were taken from the anterior and posterior aspects of the right and left upper lung lobes. Lung sections were stained with HAM-56 immunostain, which is specific for macrophages. Sixty-one cases were evaluated for the study. Three pathologists independently counted the number of macrophages per 40x field (10x ocular) in 10 contiguous fields near the center of each lung section examined. There was good agreement between pathologists on the average number of macrophages observed in each case. The mean macrophage count for all fields counted was 16.5 per 40x field (range 0-136), and the mean for individual cases was 16 (range 6.6-39.4). There was no observed difference between right, left, anterior, and posterior lung sections. There was a tendency for cases certified as sudden infant death syndrome to show lower macrophage counts than those with other causes of death, but the difference was of only marginal statistical significance. Seven of 10 cases in which infants died after a survival period in the hospital had a mean macrophage count greater than the overall mean of 16 per 40x field. These data suggest that mean pulmonary macrophage counts > 16 per 40x field may be a marker for causes of death other than sudden infant death syndrome or that there was a survival interval. These data may be useful as baseline data for further studies of infant mortality possibly involving pathologic changes in the lungs.     

大鼠百草枯中毒后体内的分布研究

目的建立生物检材中百草枯的超高效液相色谱-质谱联用检测方法,研究百草枯灌胃染毒致死的大鼠动物模型。方法大鼠以1/2 LD_(50)剂量灌胃染毒,分别于染毒后0.5h、2h、4h、8h、12h、24h、48h、72h处死解剖,采集心、肝、脾、肺、肾、脑、肌肉、膀胱和胃组织,UPLC-MS/MS法定量检测各组织中百草枯。结果试验中大鼠灌胃后,4h以内胃是主要分布器官,胃中含量最多,其他器官中含量相对较低。4h内除胃以外的脏器含量变化不大,4h后胃内百草枯含量有所下降,除胃以外的脏器含量均升高。各组织与脑组织比较具有显著性差异(P0.05)。结论百草枯在大鼠体内死后分布不均匀并且各组织含量随着时间变化有所改变。百草枯UPLC-MS/MS方法、口服染毒致死的动物模型、各组织分布规律可为甲百草枯中毒死亡案件提供检测依据。     

Validity of the use of porcine bone in forensic cut mark studies

Porcine bone is often used as a substitute for human bone in forensic trauma studies, but little has been published on its comparative mechanical behavior. The factors affecting mechanical properties and therefore selection of bone models are complex and include the age of the animal at death, and physiological loading conditions, the latter being of particular relevance when using a quadrupedal animal as a human substitute. The regional variation in hardness of adult and infant porcine bones was investigated using Vickers’ indentation tests and compared to published data for human limb bones to relate differences to inherent genetic effects and loading influences, and to examine the validity of the porcine‐human model. Significant differences in hardness were observed both along and around the adult porcine humerus and femur, but no significant differences were found along the length of the infant bones. Significant differences were found between the forelimb and hindlimb, but only in the infant specimens. The hardness values for porcine adult cortical bone from the femur (52.23 ± 1.00 kg mm^?2) were comparable to those reported in the literature for adult human cortical bone from the fibula, ilium, and calcaneus. These data will help inform subject selection in terms of both species and bone type for use in future trauma studies.     

Pulmonary hemosiderin in deceased infants: baseline data for further study of infant mortality

Infant lung samples were obtained prospectively at autopsy by medical examiner pathologists in five areas of the United States. Tissues were submitted regardless of the cause of death. Lung sections were stained with Prussian blue to detect deposits of hemosiderin. Fifty-nine cases were evaluated for the study. The four sections examined for each case were taken from the anterior and posterior aspects of the right and left upper lung. Three pathologists independently scanned the lung sections microscopically using a 10x objective lens (with 10x ocular lens) and indicated an "iron score" by indicating for each section if it showed no staining for iron-hemosiderin (Score 0), occasional staining with most fields negative (Score 1), focally abundant staining with most fields having no staining (Score 2), focally abundant staining with most fields showing positive staining (Score 3), or prominent staining throughout the section (Score 4). There was good agreement between pathologists on the iron score for each case. A total iron score was calculated by adding the scores based on each pathologist's observations. The mean total iron score was 6 (range, 1-44), with the range of possible total iron scores being 0 to 48. There was no significant difference between the four lung sections in a given case. Six cases had total iron scores that were at least twice the mean (i.e., total iron score > 12); in five of these cases death was caused by conditions other than sudden infant death syndrome, including one case in which asphyxia was the cause of death. These data are consistent with other reports that pulmonary hemosiderin in deceased infants is suggestive of a cause of death other than sudden infant death syndrome. The data may be useful as baseline data for further studies of infant mortality involving possible pathologic changes in the lungs.     

组织中三甲胺-氮浓度变化与晚期PMI关系初探

目的探索死后尸体组织中三甲胺-氮(TMA-N)浓度变化规律及其与晚期死亡时间的关系。方法健康SD大鼠66只,颈椎脱臼法处死,随机分成11组,分别于死后即刻、1、2、3、4、5、6、7、8、9、10d取大鼠肌肉、肝脏和肾脏组织,用分光光度法检测TMA-N浓度,所得数据用方差分析比较组间差异性,并进行回归方程拟合。结果3种组织中TMA-N含量随死后时间延长而增加,肌肉于死后7d、肝脏和肾脏于死后8d达到高峰,之后有所下降,并均于死后10d再次升高,肝、肾组织之间TMA-N含量比较无统计学差异性。死后2~7d内,PM I与肌肉TMA-N浓度变化拟合度最高(R2=0.969);死后3~8d内,与肝肾中TMA-N浓度变化拟合度最高(R2=0.953)。结论死后组织中TMA-N含量变化与PM I有相关性,可望为晚期PM I推断提供参考,但肌肉与肝肾TMA-N含量变化规律存在一定差异,需选择最适时段以提高PM I推断的准确性。     

Prediction of stature based on radiographic measurements of cadaver long bones: a study of the Croatian population

We tested a new approach to the stature prediction that could be used in the identification process of human skeletal remains of unknown identity. The stature of 19 female and 21 male adult cadavers was measured within 24 h after death and considered to be equal to the living stature. The antero-posterior radiographs of all limbs were taken, and the maximum length of the six long bones was measured from radiographs. There was a significant difference in the stature and maximum length of long bones between female and male cadavers (p<0.001 for all). The correlation between the stature and long bone length was the best for the humerus in females (r=0.792) and the tibia in males (r=0.891). Regression equations specific to the Croatian population were computed separately for each long bone in males and females and proven to be reliable in predicting the living stature of the individual.     

Field Study on the Attraction and Development of Insects on Human Meconium and Breast‐fed‐Infant Feces

Urogenital myiasis of newborn infants, although rare, is usually considered to indicate neglect due to attraction of flies to feces; however, infant feces have not been determined to attract insects. Human meconium and breast‐fed‐infant feces were used to determine attractiveness to insects and to examine subsequent colonization and growth patterns of insect larvae. Despite small amounts of fecal material present, adults of Lucilia sericata arrived at breast‐fed‐infant feces within five minutes; insects were rarely observed on meconium. Oviposition and growth of L. sericata larvae occurred only on breast‐fed‐infant feces; however, the larvae did not progress beyond the second instar. These data suggest that urogenital myiasis by L. sericata in newborn human infants within the first few days postpartum would not be expected, but desiccation and depletion of infested feces may provide a possible pathway for urogenital myiasis in older newborn infants.     

Gas chromatographic detection of cocaine and cocaethylene in hair of mice chronically injected with cocaine or cocaethylene and fed ethanol.

GC and GC/MS analysis was used to detect cocaine and cocaethylene in hair extracts of mice injected with 20 mg/kg cocaine hydrochloride or an equivalent dose of cocaethylene fumarate twice daily for 3 weeks. Some mice were fed liquid Lieber-DeCarli diets containing ethanol (26% of total calories) and injected twice daily with the same doses of cocaine or cocaethylene or combination of cocaine and morphine (5 mg/kg). The average concentrations of cocaine in different experimental groups were in the range of 0.9-2.4 ng/mg of hair and for cocaethylene, 2.4-2.8 ng/mg of hair. There were no significant differences in hair concentrations of cocaine among groups receiving cocaine treatment, nor were there significant difference in cocaethylene concentration in hair in the two groups administered cocaethylene. In hair extracts of mice treated with cocaine and ethanol, levels of cocaethylene were below the limit of detection.     

Alcohol intoxication may exacerbate the effects of blunt cranial trauma through changes in brain free magnesium levels

Moderate to high levels of alcohol decrease brain intracellular free magnesium concentration, a factor known to be critical in brain injury. Phosphorus magnetic resonance spectroscopy was used to examine changes to brain free magnesium concentration after blunt cranial trauma in alcohol-intoxicated rats. Rats exposed acutely or chronically to alcohol sufficient to increase blood alcohol levels to between 150 and 350 mg/dL demonstrated a brain free magnesium level that was 20-50% less than in nonintoxicated animals (p < 0.01). After injury, brain free magnesium levels declined more rapidly and to a greater extent in alcohol-affected animals than in nonintoxicated control animals (p < 0.001). As both preinjury depletion of magnesium and degree of magnesium decline after brain injury have been associated with poor recovery, these findings suggest that moderate to severe alcohol intoxication may predispose the brain to a worse outcome by reducing brain free magnesium levels, both before and after injury.     

Heart fatty acid binding protein as a marker for postmortem detection of early myocardial damage

Depletion of heart fatty acid binding protein (H-FABP) from cardiomyocytes with varying post-ischemia intervals was studied in acute myocardial infarction (AMI) model of rat, and 22 human autopsy cases were studied with streptavidin-peroxidase conjugated method (S-P). It was observed that as early as 15 min after ischemia, the depletion of H-FABP could be detected in model rats. With the ischemic time prolonged, the depletion of H-FABP was more and more evident. In all human cases with myocardial infarction, absent H-FABP staining could be found in infarcted area. And in some suspected early myocardial infarction cases, depletion of H-FABP staining could be demonstrated in areas that showed normal hematoxylin-eosin (HE) staining. The blood samples from model rats before ligation, at varying post-ischemia intervals and various postmortem time were measured for plasma concentration of H-FABP with enzyme-linked immuno-sorbent assay (ELISA) method. At 15 min after myocardial ischemia, the concentration of H-FABP was 4 times higher (546.0+/-85.3 microg/l) than that of the baseline level (103.7+/-94.1 microg/l). With the continuation of ischemic time, the concentration of H-FABP increased and peaked at 4 h (1953.5+/-405.3 microg/l), then decreased. The plasma concentration of H-FABP decreased slightly with postmortem time, but was still significant higher at any postmortem intervals than that of baseline level within 48 h after death. The results suggest that H-FABP staining can detect very early ischemic damages in human myocardium and the elevated plasma concentration of H-FABP in rat was an indicator of AMI, which was not affected by autolysis.     

A case of traumatic osteomyelitis in a victim of child abuse

A premature black female infant born at 31 weeks gestation with history of 4 weeks in the newborn intensive care unit was discharged healthy to the care of her mother and was lost to follow-up. At age 4 months the infant was found dead in bed. There was no history of trauma and no external injuries were noted. There was no attempt at resuscitation. Coroner's autopsy showed acute bronchopneumonia, 3 partially healed skull fractures, a chronic subdural hematoma, chronic intracerebral hemorrhage, retinal hemorrhages, multiple healing rib fractures, a fractured fibula, and a partially healed fracture of the distal right radius. The fracture of the right radius showed a medullary abscess of the bone surrounded by scar tissue and containing pus and granulation tissue. We believe this inflicted fracture became secondarily infected by a hematogenous route. The final diagnosis of the cause of death was pneumonia secondary to multiple blunt force trauma, and the manner of death was diagnosed as homicidal. This is believed to be the first reported case of osteomyelitis in a context of child abuse.     

Derivative spectrophotometric studies on cytotoxic effects of carbon monoxide

Characteristics of cytochrome oxidase prepared from hearts of Sprague-Dawley male rats were studied with the use of the fourth derivative spectrophotometry in respect to the cytotoxic effects of carbon monoxide (CO). CO-exposed rats tended to show lower specific activities of cytochrome oxidase than control and recovered rats. Moreover, there was a significant difference in the fourth derivative spectral features of the enzyme: CO-exposed groups indicated peaks at 412 nm in the spectra while controls at 408 nm. This spectral difference seemed to reflect specific effect of CO on cytochrome oxidase, though such trace remained for not more than a day after death.     

Bone as a biomarker of acute fluoride toxicity

The use of bone as a biomarker for chronic and acute exposure to fluoride salts has been suggested, but there are no data published about its use to evaluate lethal intoxication. One hundred and sixty rats were divided into eight groups that received a single oral intubation dose from 0 (control) to 90 mg F/kg as NaF. The animals' time of death was recorded and their femurs were removed for fluoride analysis. Acid-soluble fluoride was determined in the whole bone and on the surface (periosteal), using an ion specific electrode. The data showed a statistically significant relationship between fluoride dose and the number of deaths (P<0.0001). A statistically significant relationship was also found between fluoride dose and fluoride concentration ([F]) in either the whole femur (P<0.0017), on the surface (P<0.0001) or for the ratio periosteal [F]/whole [F] (P<0.0001). However, the [F] on the femur surface was more closely correlated with mortality than that in the whole bone, showing statistically significant differences among the lethal doses and control (P<0.05). The data suggest that the ratio [F] periosteal bone/[F] whole bone, is a biomarker for acute fluoride toxicity.     

Baboon taphonomy and its relevance to the investigation of large felid involvement in human forensic cases

Eight complete baboon carcasses were fed individually to two captive leopards. These experimental feedings generated two separate bone assemblages, one composed of those bone specimens not ingested by the leopards (i.e., the refuse assemblage), and one composed of those bone specimens ingested and subsequently voided by the leopards (i.e., the scat assemblage). The two assemblages are separable using measurements of skeletal part representation. Distinguishing characteristics of the assemblages are summarized and explained in relation to observations of leopard feeding behavior and intrinsic qualities of baboon postcranial bones (i.e., bulk bone mineral density, maximum length, volume and cross-sectional area). Because baboons and humans share the fundamental primate body plan, these baboon carcasses approximate human cadavers ravaged by large felids. Thus, our results can inform death scene investigators about the expected human body part representation in large felid feeding residues versus those expected in regurgitations and feces. Since different body parts have different body-identification potentials, knowing these expected differences in body part representation is particularly valuable in forensic settings.     

The effect of chilling, freezing, and rewarming on the postmortem chemistry of vitreous humor

The effect of chilling at the time of death on the postmortem chemistry of the vitreous humor was studied by using sheep heads obtained immediately following decapitation. One group of heads was kept at room temperature, while the remainder were chilled on ice or in ice water, then refrigerated or frozen. Vitreous humor specimens were taken at intervals over a 48-h period. Chilling inhibited the fall in the glucose concentration and the total carbon dioxide content and lessened the increase in lactic acid, compared to the room temperature group. Rapid glycolysis resumed when the heads rewarmed to room temperature starting at 6-h postmortem, but did not resume at later points. The rate of rise of the potassium and magnesium concentrations was also diminished in the chilled eyes. Freezing and thawing caused an abrupt increase in the potassium and magnesium levels, but other solutes were unaffected.