Retrospective Study Of Forensic Practice Of Corpses Recovered Out Of Water From 2000 To 2009 And Expression Of Sp-a In The Drowned Lung

【Background and Aims】Investigation of bodies recovered out of water comprises an important proportion of the medico-legal requests , especially in districts along rivers and near coasts in South China. However, the key question whether the victim died due to'true'drowning can frequently not easily be solved. Postmortem phenomena considered as valuable indications include: the plume of froth at the mouth and nostrils, aqueous emphysema, plants catched in hand, et al. The pitfall is that most of these findings are non-specific, quite transient and can only be found in fresh drowned bodies. In addition, postmortem injuries can be formed during the body's drifting in river, making the investigation more difficultly.Among the laboratory tests, diatom test as a important auxiliary reference in diagnosis of drowning engendered a lot of criticism and controversial. In recent years, forensic practisians try to seach better laboratory tests in diagnosis of drowning, such as haemodilution tests, plankton chlorophyll A, et al. However, the investigation of the value of these methods has not been generally recognized.Practisians found that spleens in drowned bodies often shrinked, aqueous emphysema guradually shriveled and an amount of pleural effusion appeared, along with the postmortem intervel longer. Then, calculated the ratio between the total weight of the lungs and pleural effusion and the weight of the spleen, and found the ratios were significant differences between drowning and the other causes of death. Animal experiments showed that pulmonary surfactant to maintain alveolar tension as an important material. When the fluid entered into the alveoli, pulmonary surfactant would fiercely change. Japanese scholars proposed a hypothesis that the pulmonary surfactant protein A (SP-A) would be considered as a diagnostic indicator of drowning.According to the aspects above, 186 cases of forensic investigation about corpses recovered out of water were selected from Department of Forensic Pathology from 2000 to 2009. statistics and analysis of several aspects include: the general, diatom test, and pathology examination of major organs, Immunohistochemistry technology (SP-A staining) was used to detect the SP-A protein expression between the drowned lung and the control group, in the hope that a certain distribution of corpses recovered out of water could be seached, and reseach-bases for forensic ivestigition of corpses recovered out of water could be provided.【Materials and Methods】186 cases of forensic investigation about corpses recovered out of water were selected from Department of Forensic Pathology from 2000 to 2009. (1)The 186 cases about corpses recovered out of water were classified according to different standards in order to obtain their general eatures by use of Excel software. (2)statistics and analysis of several aspects:diatom test, lung and spleen pathological changes, and pleural effusion. (3)Select 5 cases of drowning as the experimental group, and 5 cases of mechanical asphyxia caused by external forces as controls. Observe after paraffin sections by immunohistochemistry SP-A staining, select visions of measurement randomly for photographs, compare lung tissue SP-A positive staining distribution (granular aggregates or linear membranous loops) of the two groups, and analyse the changes in characteristics of SP-A is correlated with the drowning.【Results】(1)①Statistics suggested that forensic identifications about corpses in water take a high proportion in the past ten years(4.07%-11.07%).②About examine contents, cases of only requesting diatom test taken a higher proportion, requesting diatom test and pathology examination a little lower proportion, the autopsy examination the lowest proportion.③The corpses found in season, the most cases in summer, next in spring and autumn (nearly no difference), the least in winter.④Distribution in different waters, 74 cases in rivers (39.48%), 58 cases in lakes and pools (31.18%), two types above accounted for the majority of corpses in water.⑤Men (119 cases) were significantly more than women (66 cases).⑥The 186 cases of corpses in water were mostly young people, of which 77 cases were in the ages of 10～30 years(48.43%), and 27 cases were unidentified bodies(14.52%).⑦The natures of deaths were mostly undefined.⑧The majority of the corpses in water for forensic identification were corrupt. (2)①Aqueous emphysemas were distinct in early drowned bodies (80%).②In this study, age of 18～39 years, spleen weights of 13 cases o the male drowned were lighter, compared with the average weight in literature, but t-test showed no significant difference.③Detection rate of diatoms in organs of the drowned was significantly higher than the non-drowned. (3)Positive stainings in the drowned lung were mostly granular aggregates in the alveolar cavity, in contrast, mostly in the control group. The number of linear and membranous positive stainings in drowned lung was less than that of the control group, and the difference was statistically significant.【Conclusions】The experimental results show that: (1)Statistics suggested that forensic identifications about corpses in water taken a high proportion, the majority of which were corrupt and difficult for conclusion; in general, there was a certain distribution of corpses recovered out of water in sex, age, season, water, etc. (2)The important pathological features include: aqueous emphysema, pleural effusion, combined with diatoms test in the diagnosis of drowning is significant, especially positive in the liver, kidney and spleen for the diagnosis of drowning more meaningfully.According to corrupt postmortem in water, A mount of pleural effusion in diagnosis of drowning had an important value. (3)The changes in characteristics of SP-A is correlated with the drowning, but the exact relationship and application prospects remain to be further research.