SEM/EDAX检测内脏异物元素成分诊断溺死

为探讨溺死诊断的依据和推断入水地点，用扫描电镜／X－射线谱仪（SEM／EDAX）检测19例溺死尸体及28只溺死兔的肺、肾、心、肝等组织异物颗粒及其元素成分和含量，并以陆地上死亡尸体14具及8只陆地上勒死兔（2只勒死后入水浸泡6天）作实验对照。结果发现，19例溺死尸体及28只溺死兔的肺边缘区呼吸性细支气管、肺泡管、肺泡囊及肺泡内均可见高能谱值的异物颗粒，其大小自数微米至数十微米不等，多为无定形异物颗粒或细小异物颗粒集落。其中元素成分为硅、铝、钙、铁、铬、钛、钼、铅、锡、铜、溴等，与入水地点溺液中所含元素成分相同；肾、心、肝组织异物颗粒检出率分别为77％、53％及47％，数量较少，颗粒较小，大小自1微米以下至十数微米。非溺死尸体及实验兔的肺、肾、心、肝组织未检出或偶尔检出异物颗粒，其元素成分多为铁、钙或硅等，可能是病理及生理性异物颗粒，如含铁血黄素、钙化灶等。用SEM／EDAX检测水中尸体组织中异物颗粒及其元素成分和含量，可以诊断溺死，推断入水区域，为明确案件性质和确定侦察范围提供科学依据。     

Post-mortal lesions in freshwater environment

Postmortem animal feeding activity may cause considerable damage to bodies resulting in the modification of wounds, loss of identifying features and injury. Certain postmortem lesions may appear inflicted or non-inflicted antemortem injuries. At present, apart from cases in sea water, no data are available about post mortal lesions performed by aquatic organisms. This note that represents the first report concerning colonisation of a dead body by crustaceans a few hours after death, describes injuries caused by the amphipod Niphargus elegans on the face, and in particular on the eye region, of a young man dead by drowning. The lesions recorded in this case are comparable with the lesions caused by ants. The high plasticity in the food choice can allow Amphipoda to colonise drowning bodies in every moment after dead, however the benthonic behaviour of these animals suggests a more important role in the colonisation during post-mortem submersion periods.     

The forensic medical evaluation of the results of determining diatomaceous plankton in the diagnosis of drowning

Evaluation of demonstrative value of method based on diatom plankton determination as a diagnostical sign of death due to drowning was performed. Plankton was detected in the viscera in 37% of cases (as a whole 376 bodies of people who drowned in fresh water were examined). Plankton was detected in aspiration type of drowning and its mixed variant. In spastic and reflector types of drowning plankton wasn't detected. According to author's opinion this method is an objective diagnostical test to determine the cause of death of people when their bodies are found in water.     

Ciliated protozoa and thanatology

Different ciliated protozoa are observed by the immersion of dead bodies in soft water. In death from drowning a ciliated Tetrahymena kind was discovered whose size and hemotactism facilitate in a priviliged way the penetration in the internal medium through pulmonary channels. Diagnosis in blood was easy by putting this organism in culture. This method had an astonishing power of reproduction. This search fortunately completes the series about diatoms by means of corroboration on the diagnosis of drowning.     

扫描电镜/能谱观察溺死和死后入水的法医学应用研究

目的探讨扫描电镜/能谱分析在溺死的法医学鉴定中的作用。方法实验选用20例已知生前入水尸体,11例已知的死后入水尸体和2例陆地死亡尸体。在每个肺叶各取3个切面,每个切面用扫描电镜取样台胶面与肺叶的切面充分接触,另在落水地点取水样一份,进行对比。扫描电镜取样台胶在切面上充分接触后封闭取材盒,真空干燥后,直接在扫描电镜下进行观察。结果20例生前入水尸体在肺组织中均检出异物颗粒,并且与对照水样中检出的异物颗粒相吻合;而死后入水的尸体和在陆地上死亡的尸体肺组织中均未检出明显的异物颗粒,3者比较P<0.0001。在肺组织支气管切面中,生前入水的20例中有15例检出异物颗粒,在边缘肺切面及中间切面中分别有13例检出异物颗粒,统计学无明显差异。结论本实验建立的肺脏内异物颗粒取材方法准确可靠实用。对综合判断案件的性质,判断溺死尸体入水地点的具有积极意义。较好地解决了实验室检验中的污染问题。腐败尸体对检测结果无影响。     

Circumstances and macropathologic findings in 1590 consecutive cases of bodies found in water

The diagnosis of drowning relies primarily on critical examination of the subject's individual characteristics, circumstances, and postmortem macropathologic changes. In this retrospective study, based on 1590 consecutive cases of bodies found in water and undergoing autopsy at the Department of Forensic Medicine, University of Helsinki, from 1976 to 1998, the frequency of circumstantial data and macropathologic changes crucial for the diagnosis of drowning were determined. The fatal events were eyewitnessed in 403 cases (25.3%), and suicide notes were found in 83 cases (5.2%). External foam, frothy fluid in airways, and overlap of the anterior margins of lungs were found in 275 (17.3%), 739 (46.5%), and 669 (42.1%) of the cases, respectively, but no one of these changes, tested against dry-land controls, were specific for drowning. The association of external foam and overlap of the lung margins was exclusive of drowning but was observed in only 176 cases (11.1%). After cross-analysis, 964 (60.6%) of the cases had no circumstantial data or macromorphologic pathologic findings that allowed a definite diagnosis of drowning. The diagnostic problems in putative drowning cases, based on this study sample, have not been overrated. Studies to investigate and improve the reliability of complementary methods for the diagnosis of drowning are warranted.     

Selective culturing and genus-specific PCR detection for identification of Aeromonas in tissue samples to assist the medico-legal diagnosis of death by drowning

The detection of autochthonous aquatic bacteria in tissue samples from drowning cases is increasingly considered as an alternative approach to assist the medico-legal diagnosis of death by drowning. Bacteria belonging to the genus Aeromonas may be suitable candidates for this application as they are ubiquitous in natural aquatic environments but are generally not part of the human microbiota. The research aims of this study were (i) to develop a sensitive, specific and rapid screening and confirmation method for Aeromonas species in tissue samples and (ii) to evaluate aseptic sternal puncture as a post-mortem sample technique and bone marrow as an alternative matrix to provide evidence of death by drowning. The presence of Aeromonas in tissue samples was verified by cultivation using the selective media Ampicillin Dextrin Agar (ADA) and Ryan's Aeromonas Medium. The use of ADA medium was found most optimal for the sensitive, inexpensive and quick detection of aeromonads in human tissue samples. Positive culture plates were confirmed by harvesting all colonies for DNA extraction and subsequent PCR amplification using Aeromonas genus-specific primers. Aeromonads were detected in lung swab, blood and bone marrow of drowned bodies (n=3), but were negative in these three matrices for all negative controls (n=90) tested. Bone marrow proved to be a suitable alternative matrix and can be sampled post-mortem by an aseptic sternal puncture. In conclusion, this study confirms previous indications that aeromonads in cultures from blood of water bodies can be considered a potential marker for drowning. Given the fact that the number of immersed bodies (drowned and non-drowned) included in this study is statistically not significant, however, more tissue samples need to be investigated to confirm the validity of these methods to aid the diagnosis of death by wet drowning.     

东莞溺死案多发河段硅藻种群分布及其法医学意义

目的调查东莞溺死案多发河段硅藻种群分布,探讨其在溺死地点推断中的意义。方法于2009年6月至9月收集东莞市东江沙田、道滘、麻涌、石碣、石龙、茶山和企石共7个河段采样点江水样本126份,并收集2例已知落水地点溺死尸体;制作各样本硅藻涂片,计算样本间Sprensen相似系数及弦平方距离(SCD),并进行聚类分析。结果 126份水样中共鉴定出70种硅藻,其中优势度>0.02的优势种群有4种;2个案例样本分别与道滘和石碣河段样本的相似度最高,与实际落水地点基本一致。结论建立区域性溺死多发河段硅藻数据库,利用Sprensen相似系数及SCD值及聚类分析进行落水地点推断具有一定可行性。     

Scanning electron microscopy: application in the identification of diatoms in cases of drowning.

A simple and rapid method is described for processing organ and water samples for the identification of diatoms so that they can be studied and recorded for taxonomic and diagnostic purposes. Samples are treated with concentrated nitric acid; the fluid obtained is centrifuged, and its sediment is dried, coated, and examined under the scanning electron microscope. The method does not alter the morphology of diatoms and allows the study of freshwater and seawater species present in the organs of bodies found in the water, making possible the diagnosis of drowning under specific conditions.     

Comparison between Temperature Gradient Gel Electrophoresis of Bacterial 16S rDNA and Diatom Test for Diagnosis of Drowning

When a body is discovered in water, it is difficult to conclude whether the cause of death was drowning, even today. Although diatom testing by the digestive method is classical, we hypothesized that aquatic bacteria, as well as diatoms, might be detected in drowned bodies, and conducted temperature gradient gel electrophoresis (TGGE)‐targeting 16S rDNA. DNA was extracted from the site water, and from heart blood and liver samples from 27 bodies concluded as drowning deaths by autopsy and subjected to TGGE after amplification of 16S rDNA by polymerase chain reaction. We observed whether the feature point of each 16S rDNA from the site water and blood or liver samples matched. Considerably higher correspondence was observed in drowned bodies, and the rate was higher than that achieved with the digestive method. Moreover, TGGE is safer than the digestive method. Our study suggests that this method can aid diagnosis of drowning.     

Diagnosing death by drowning in fresh water using blood strontium as an indicator

The interpretation of the level of strontium (Sr) in blood has been demonstrated to be useful in the diagnosis of death by drowning occurred in sea water, but its use in fresh water drownings is not so evident because of the low Sr concentration present in most of fresh water media. In this paper, we show a survey of the results obtained in the casework analysis of Sr in ventricular blood used in the diagnosis of drowning in 144 bodies found immersed in fresh water over a period of 10 years. Thirty-two percent of the immersion cases examined could be diagnosed as drownings with a reasonable degree of confidence. It is thought that this percentage of positive diagnoses could be largely improved in the case of blood samples taken a few hours after death.     

A promising microbiological test for the diagnosis of drowning

A number of biological and chemical tests have been developed over the years to determine whether a person was drowned. This study focuses on the potential of a microbiological test for detecting common bacterial markers of water faecal pollution such as faecal coliforms (FC) and faecal streptococci (FS) as possible indicators of drowning. A promising previous study was carried out on central and peripheral blood samples of 42 drowned victims (20 cases in saltwater and 22 cases in freshwater) and 30 not-drowned bodies. To improve the accuracy of our previous results and also in order to investigate a possible cause of a false positive due to pulmonary passive diffusion and subsequently endogenous or exogenous bacterial invasion of the blood in the post-mortem interval (PMI), the FC and FS test was applied to bodies submerged in water but died from causes other than drowning. In the present study, blood samples collected from the left ventricle (LV), right ventricle (RV), femoral artery (FA) and, femoral vein (FV) of 10 drowned victims (5 cases in freshwater and 5 cases in seawater) and 3 not-drowned individuals with bodies submerged in water for a while after death have been analysed. Preliminary results are in agreement with other reports dealing with diatoms and marine bacteria that suggest to exclude the hypothesis of a passive penetration of sufficient quantities of drowning medium into circulation after death or during the agonal period. Based on our results there is also no evidence of a relevant dissemination of endogenous micro-flora from the gastrointestinal tract affecting the FS and FC test. There are still several other factors that could influence the applicability of post-mortem FS and FC cultures for the diagnosis of drowning and they need further investigations. The present article provides only a glimpse of the potential of the FS and FC test as bacteriological method for the diagnosis of drowning.     

Fatal Drowning Accident and Undiagnosed Hydrocephalus

Abstract: Bodies found in water present several diagnostic challenges for the forensic examiner, such as the identification of the time and mechanism of death, the postmortem submersion time, and above all the circumstances of drowning. We report the case of a 33‐year‐old security guard found dead in Venice, in the water of the lagoon, who at autopsy presented a previously undiagnosed hydrocephalus with macrocephaly. The victim remained asymptomatic until 2 months before death and had never undergone a neurological or radiological examination. In the article, we emphasize the need to perform a thorough autopsy in all suspected drownings, discuss the etiopathogenesis of the neurological disease and hypothesize a possible relationship between the hydrocephalus and the drowning accident. Finally, we discuss the major clinical and forensic implications of macrocephaly and hydrocephalus in adults.     

Prevalence of diatom frustules in non-vegetarian foodstuffs and its implications in interpreting identification of diatom frustules in drowning cases

Detection of diatom frustules in bone marrow (diatom test) is used for diagnosing ante-mortem drowning where the usual signs of drowning are not present in dead bodies recovered from water. However, controversies over the reliability of diatom test results are continuing. There have been indications on the possibilities of diatoms entering into systemic circulation from atmospheric air, food and drink. While diatoms have been demonstrated in the gut content of edible marine forms such as shrimps and clams, the present study, for the first time, provides empirical evidence on the prevalence as well as abundance of diatom frustules in the samples of cooked non-vegetarian foodstuffs that impend human consumption in Kelantan, Malaysia. It is found that 50 g each of cleaned and cooked prawns and of clams impending human consumption contain about 8360 and 29,054 diatom frustules, respectively. A person accustomed to prawn and clam food would be ingesting an estimated 2 million diatoms in a single year. Considering the suggestion that detection of five diatom frustules in 10 g of bone marrow would suffice for concluding drowning as mode of death, and the fact that there is yet no proof that diatom frustules do not enter into the human systemic circulation through the digestive tract, the estimated number of diatom frustules routinely ingested acquires significance since entry of a few of such ingested frustules into the systemic circulation can lead to false positive test results. The findings of this research raise two important issues: first, population based routine food related diatom ingestion requires to be estimated, and, second, studies have to be initiated to categorically prove or disprove the possibility of entry of diatom frustules into the systemic circulation via the digestive tract.     

Drowning without aspiration: is this an appropriate diagnosis?

It has been reported that 10-15% of drowning victims do not aspirate water. We have revisited the original studies quoted to reach this conclusion and find it is without foundation. Sudden cardiac standstill is known to occur on land and, therefore, may also occur when the victim is in water. In the absence of the common finding of significant pulmonary edema in the victim's respiratory system, to conclude his or her death was caused by "drowning without aspiration" is unwise. All causes of sudden death that might occur in which respiration may not take place should receive serious consideration when examining bodies with such findings that are found in water.     

The Impact of Discontinuation of the Medical Examiner System: Cases of Drowning in the Bathtub at Home

The incidence of death by drowning greatly varies among different prefectures in Japan, mainly due to climate difference. However, there could be other factors affecting the incidence of deaths besides climate, for example, differences in regional death investigation systems. Here, we aimed to elucidate other such factors affecting the mortality data of drowning in the bathtub, especially the effects of discontinuing the medical examiner system. Police data in Kyoto and ambulatory care information in Yokohama were used. Data on cases of elderly individuals found dying or dead in the bathtub at home in winter 2014–2015 were obtained. The following data were collected for each case: age, gender, presence/absence of ambulatory transport, performance of autopsy, and cause of death. The autopsy and drowning rates in Kyoto were 0%, whereas both values in Yokohama were significantly higher at 93.1% and 89.4%, respectively (the denominator of each of the rates is the total number of elderly (aged 65 or over) individuals found dying or dead in the bathtub at home in each city during each winter). Despite no significant difference of incidence of total bath-related death, the proportion of drowning-related deaths was overwhelmingly higher in Yokohama than in Kyoto. The difference can be attributed to the difference in autopsy rates between the two cities, mainly caused by the presence/absence of a medical examiner system. Therefore, we should pay careful attention to future changes in autopsy/drowning rates in Yokohama, and ascertain whether the change might be continuously influenced by the abolishment of this system.     

溺死尸体器官硅藻检出率季节性差异

目的 研究溺水死亡者肺、肝、肾、骨髓等器官淡水硅藻检出率可能存在的季节性差异,为法医学解决水中尸体死因鉴定提供技术帮助与科学证据.方法 收集2009～2011年1、4、7、10月沈阳市浑河中溺死尸体每月(组)各5例;45只家兔分相应月份生前、死后入水组及对照组,分别于当月发现水中尸体后第2天入水,取人及兔肺、肝、肾、股骨骨髓及现场水样备检,应用酶消化法检测各组器官中硅藻数量、种属并与现场水样比对.结果 各组溺死尸体肺中均检出多量硅藻且种属与现场水样一致,春、秋及冬季溺死尸体肝、肾中仅可检出少量体积较小的小环藻等中心纲硅藻,夏季肝、肾及骨髓中均未检出硅藻;各组溺死家兔肺中均检出少量小环藻等中心纲硅藻,肝、肾及骨髓中未检出硅藻.结论 硅藻种群的季节性变化及不同种群硅藻体积的差异可能造成肝、肾等大循环器官中硅藻检出率的季节性差异;仅肺中检出硅藻,肝、肾中硅藻检验结果阴性并不能排除溺死可能.     

Detection of diatoms in bone marrow (femur) of nondrowned (author's transl)

Diatoms in the bone marrow (femur) of 16 nondrowned bodies were detected by a modern method of ultrafiltration. The rate of diatoms were found to be in the same range as in cases of drowning. The results deny the proof of diatoms even in bone marrow to be useful any longer for the diagnosis of death from drowning.     

Detection of marine and freshwater bacterioplankton in immersed victims: Post-mortem bacterial invasion does not readily occur

We previously applied our method of detecting marine or freshwater bacterioplankton (bacteria) in the blood of immersed victims as a marker of drowning. However, we did not confirm the absence of post-mortem bacterial invasion during immersion. Here we examined the nature of bacterioplankton in blood samples from 21 immersed and 4 non-immersed cadavers. We found only freshwater bacterioplankton in the blood of two victims that were retrieved from the sea or an estuary inhabited by marine bacterioplankton even though one victim was highly putrefied. The results of diatom testing suggested that these two victims had drowned in fresh or brackish water with low salinity and then flowed out to the estuary or the sea. Two others were submerged in water, but representative bacterioplankton were undetectable in their blood although one victim was highly putrefied. Autopsy findings and the results of diatom tests did not indicate that the cause of death was drowning. As in previous studies, we identified freshwater bacterioplankton in the blood of seven other victims that had drowned in freshwater, marine bacterioplankton in the blood of four victims that had drowned in seawater and none in four victims found on land that had died by means other than drowning. Bacterioplankton in the blood of drowned victims appears to reflect the type of water aspirated and blood does not become easily contaminated with bacteria post-mortem even in decomposed bodies.     

Study of the diagnostic value of iron in fresh water drowning

The aim of our study was to test the diagnostic value of iron (Fe) in fresh water drowning by investigating the postmortem levels of hemodilution in drowning cases compared to control cases. Twenty-six typical fresh water drowning cases were selected from 128 immersion cases autopsied in our Department of Forensic Pathology between 1998 and 2004. The exclusion criteria were a long postmortem interval and other causes of death than drowning. For all selected cases, the diagnosis of drowning was based on the presence of autopsy findings and positive diatom test. A control population of 12 cases was also selected. For each drowning and control case, iron blood levels were measured in the left ventricle (LV) and right ventricle (RV) of the heart. The mean difference of iron concentration (RVFe-LVFe) between the drowning group and the control group was statistically compared. Furthermore, iron measurements were performed in 19 drowning cases showing advanced putrefaction. The mean difference of iron concentration was significantly higher in the drowning cases compared with controls (P<0.001). All drowning cases showed hemodilution. No overlap was found in the RVFe-LVFe levels between the two groups. Resuscitation attempts seemed to have no effect on the results. In cases of drowning showing advanced putrefaction, the iron test was not reliable because biochemical iron measurement was often prevented by no sufficient blood in the heart or postmortem clots. In conclusion, according to our results, iron seems to be a good biochemical marker in fresh water drowning with a short postmortem interval.