OBJECTIVES: To detect diatom in the organs of drowners by enzyme combined with strong acid digestion method, and evaluate its application value. METHODS: A total of 40 cases which have been identified as drowning in local region were collected. Samples of the lung, liver, kidney, and the water of the scene were also gathered from each case. Strong acid digestion method, enzyme combined with strong acid digestion method, and enzymic digestion method were respectively performed to detect the diatom in the samples. The comparative analysis was made on digestion time, digestive power and detection rate of diatom, etc. RESULTS: Enzyme combined with strong acid digestion method was significantly better than enzymic digestion method on digestion time and digestive power; enzyme combined with strong acid digestion method were obviously superior to strong acid digestion method on the detection rate of diatom. CONCLUSIONS Enzyme combined with strong acid digestion method combines the advantages of strong acid digestion method and enzymic digestion method. It has the characters of operation safety with little pollution to environment, which is worthy of further popularization and practice.
Diatoms/isolation & purification* ; Drowning ; Forensic Pathology/methods* ; Humans ; Kidney/metabolism* ; Liver/metabolism* ; Lung/metabolism*

OBJECTIVE: To determine the expression of water channel 1 protein in the lung of drown rat and that of after death thrown into the water. METHODS: Immunohistochemical method was used and the computer image analysis was conducted to detect the distribution of AQP1. RESULTS: The positive expression of AQP1 was seen in the capillary endotheliocyte of the interstitial and around bronchi and in the alveolar endothelial cells. The value of intergrated optical density was statistical significant. CONCLUSION It suggests that AQP1 is one of sensitive signs to distinguish ante-mortem and postmortem immersion.
Animals ; Aquaporin 1 ; Aquaporins/metabolism* ; Drowning/metabolism* ; Endothelial Cells/metabolism* ; Immunohistochemistry ; Lung/metabolism* ; Membrane Proteins/metabolism* ; Rats ; Rats, Sprague-Dawley

OBJECTIVES: To study whether diatoms can enter the body through the lymphatic system of the digestive tract. METHODS: Twenty experimental rabbits were divided into the test group and the control group randomly, and intragastric administration was performed with 20 mL water sample from the Pearl River and 20 mL ultrapure water, respectively. After 30 min, lymph, lungs, livers and kidneys were extracted for the diatom test. The concentration, size and type of diatoms were recorded. RESULTS: The concentration of diatoms of the test group was higher than that of the control group (P<0.05). In the test group, Stephanodiscus, Coscinodiscus, Cyclotella, Melosira, Nitzschia, Synedra, Cymbella, and Navicula were detected; in the control group, Stephanodiscus, Coscinodiscus and Cyclotella were detected. The long diameter and the short diameter of diatoms of the test group were higher than those of the control group (P<0.05). In the test group, 1-2 diatoms were detected in 3 lung samples and 2 liver samples, which were Stephanodiscus or Cyclotella, and no diatoms were detected in the kidney samples; in the control group, 1-2 diatoms were detected in 2 lung samples and 3 liver samples, which were Stephanodiscus or Coscinodiscus, and no diatoms were detected in the kidney samples. CONCLUSIONS Diatoms can enter the body through the lymphatic fluid, which is one of the reasons for the presence of diatoms in tissues and organs of non-drowning cadavers.
Animals ; Diatoms ; Drowning ; Gastrointestinal Tract ; Lung ; Lymphatic System ; Rabbits ; Water/metabolism*

OBJECTIVE: A novel technology for detection of diatom was discussed. METHODS: Five grams of testing sample were taken and the organics were removed using simple mechanical knead pulp method. The homogenized samples were concentrated by centrifugation, smeared, and then examined under light microscope. RESULTS: Except for a few feather's grains, the vast majority of diatom could be identified easily with clear diatom striations. The organic diatom could also be easily detected by this methodology. CONCLUSION The detection of diatom using knead pulp method is not only simple and inexpensive with a higher successful rate, but also causes nearly no harm to human and environment.
Calcium/metabolism* ; Diatoms/ultrastructure* ; Drowning/diagnosis* ; Forensic Pathology ; Humans ; Kidney ; Liver ; Lung ; Microscopy/methods* ; Specimen Handling/methods* ; Tooth

OBJECTIVE: To investigate the advantages of nitric acid digestion method and its differences with the traditional method. METHODS: Ethanol was used to fully fix the testing sample. About 80-100 g of the testing samples were cut into pieces and digested with nitric acid. It was then centrifuged and washed to remove organic components. Smears were prepared and examined under the light microscope. RESULTS: The diatom had been identified with clear striations, counted conveniently and classified easily. CONCLUSION The improved nitric acid digestion method is not only simple with a higher successful rate of detection, but also can prevent interference from contamination. It can improve the stability of the experimental results, avoid harm to human and environment, and provide higher safety in the course of experiment.
Autopsy ; Diatoms/isolation & purification* ; Drowning ; Forensic Pathology ; Humans ; Kidney/metabolism* ; Liver/metabolism* ; Lung/metabolism* ; Nitric Acid/chemistry* ; Postmortem Changes ; Tissue Fixation/methods*

OBJECTIVES: To observe the changes of expression of aquaporin-1（AQP-1） and AQP-4 in drowned and postmortem immersed rats' lungs. METHODS: Thirty healthy male Wistar rats were randomly divided into drowning group, postmortem immersion group and cervical dislocation group. The morphological changes of rats' lungs were observed using HE staining. The mRNA and protein expressions of AQP-1 and AQP-4 in rats' lungs were detected by real-time PCR, immunohistochemistry and Western blotting, respectively. RESULTS: The results of immunohistochemistry and the Western blotting showed that the protein expression of AQP-1 of the drowning group was higher than the postmortem immersion group and the cervical dislocation group （P<0.05）. The result of immunohistochemistry showed that the protein expression of AQP-4 of the drowning group was higher than the postmortem immersion group and the cervical dislocation group （P<0.05） while no difference were detected among the three of them by Western blotting （P>0.05）. The mRNA expressions of AQP-1 and AQP-4 in rats' lungs of the drowning group was significantly higher than the postmortem immersion group （P<0.05）. CONCLUSIONS The increase of mRNA and protein expressions of AQP-1 and AQP-4 in lungs of rats with cute lung injury of the drowning group would be useful for differentiating vital drowning from postmortem immersion.
Animals ; Aquaporin 1/metabolism* ; Aquaporin 4/metabolism* ; Autopsy ; Blotting, Western ; Drowning ; Immunohistochemistry ; Lung/metabolism* ; Male ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar ; Real-Time Polymerase Chain Reaction

Pericardial fluid is a kind of serous fluid in pericardial cavity. Because blood undergoes postmortem changes such as autolysis and putrefaction, vitreous humor is limited,cerebrospinal fluid is easily mixed with blood, pericardial fluid, on the other hand, exists in a closed cavity and can be hardly contaminated by postmortem changes, and also is easily obtained. Pericardial fluid not only plays an important role in clinic practice, but also is widely applicable in forensic practice. This paper briefly presented the properties of pericardial fluid and its clinical significance. It reviewed biochemical changes in decedents died of heart diseases, drowning and asphyxia, and explored the significance in medico-legal investigation. Moreover, application of pericardial fluid in forensic serology, forensic toxicological analysis and other fields were also discussed. Pericardial fluid analysis may provide important information for determination of the cause of death with further investigation concerning forensic applicability of pericardial fluid.
Asphyxia/pathology* ; Atrial Natriuretic Factor/metabolism* ; Biomarkers/metabolism* ; Calcium/metabolism* ; Drowning/pathology* ; Forensic Pathology ; Heart Diseases/pathology* ; Humans ; L-Lactate Dehydrogenase/metabolism* ; Magnesium/metabolism* ; Myocardium/metabolism* ; Natriuretic Peptide, Brain/metabolism* ; Pericardium/metabolism* ; Postmortem Changes ; Troponin I/metabolism*

OBJECTIVETo observe changes of thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha(6-Keto-PGF1 alpha) and TXB2/6-Keto-PGF1 alpha (T/P) in lungs of rats drowned in hypothermic sea water and to assess their influence on the blood-gas.

METHODSRats of different groups were drowned nearly to death in hypothermic sea water and then taken out of the water rapidly, observed at room temperature, after that the following steps were taken in 5, 15, 30, 60, 240 min and 360 min groups, that were 1 ml arterial blood taken from left heart for blood-gas analysis including pH, PaO2 and PaCO2, rectal temperature observed; at last, the ratio of left dry lungs with left wet lungs was assessed, TXB2 and 6-Keto-PGF1 alpha in right lungs were examined in all above groups and dead group(14 rats dead, only 4 examined).

RESULTSThe rectal temperature[(20.13 +/- 0.48) degree C], pH(6.68 +/- 0.03), PaO2[(45.00 +/- 6.30) mm Hg)], TXB2[(97.46 +/- 17.46) ng/L] and 6-Keto-PGF1 alpha[(25.59 +/- 8.12) ng/L] dropped to the lowest point in the 5 minutes group(P < 0.01), while PaCO2[(89.18 +/- 5.10) mm Hg] reached the highest point(P < 0.01), all above items from 5 minutes group then showed a recovering tendency, but only the pH in 240 minutes and 360 minutes groups as well as TXB2 in 360 minutes group and dead group reached near the level of normal control groups (P > 0.05); T/P had a rising tendency and reached the highest point in the 360 minutes group.

CONCLUSIONSThe production and secretion of TXB2 and 6-Keto-PGF1 alpha were influenced by hypothermia, hypoxemia and acidosis, the imbalance of T/P could be one of factors influencing the improvement of blood gas index.

6-Ketoprostaglandin F1 alpha ; analysis ; Animals ; Body Temperature ; Carbon Dioxide ; blood ; Drowning ; metabolism ; Hypothermia ; metabolism ; Lung ; chemistry ; Oxygen ; blood ; Rats ; Seawater ; Thromboxane B2 ; analysis