Autopsy by forensic pathologist is a main mean currently to determine the cause of sudden unexpected death. Retinal examination is important but seldom performed during a forensic autopsy for various reasons. The value of retina examination has not been recognized. With invention of ophthalmic endoscopy and its subsequent application in postmortem retina examination, it has proved to be useful adjunct to determine the cause of death and to estimate the postmortem interval.
Adult ; Autopsy ; Cause of Death ; Craniocerebral Trauma/pathology* ; Decompression Sickness/pathology* ; Female ; Forensic Pathology/methods* ; Humans ; Male ; Middle Aged ; Ophthalmoscopy ; Retina/pathology* ; Subarachnoid Hemorrhage/pathology* ; Syndrome ; Vitreous Hemorrhage/pathology*

OBJECTIVETo investigate the effect of different pressure oxygen pre-breathing in preventing decompression sickness of rats.

METHODSForty male SD rats were randomly divided into 4 groups: decompression sickness (DCS) group and three oxygen pre-breathing groups with 1 ATA, 2 ATA and 3 ATA pressure respectively. The rats of DCS group were placed in the hyperbaric chamber and the chamber was compressed evenly within 3 minutes to depths of 7 absolute atmosphere(ATA) and held at the designated depth for 60 min, then decompressed (3 min) at constant speed to the surface pressure. After that, the rats were taken out for further detection. While the rats of oxygen pretreatment groups pre-breathed different pressure oxygen for 20 min before entering into chamber. The mortality and behavioral of rats were observed with 30 min post decompression. The dry/wet ratio of the lung, protein levels in the bronchoalveolar lavage fluid (BALF), and the inflammatory cytokine tumor necrosis factor (TNF-alpha) expression were also tested.

RESULTSCompared with that of the DCS group, the mortality and morbidity of oxygen pre-breathe groups didn't change obviously. But the total BALF protein level and the inflammatory cytokine TNF-alpha expression of 1 ATA oxygen pre-breathe group were obviously decreased, while the dry/wet ratio of lung as obviously increased instead (P < 0.05).

CONCLUSIONAlthough preoxygenation can' t obviously change the mortality and mobidity of rats, normal pressure oxygen pre-breathing can mitigate the protein infiltration in BALF and the expression of inflammatory cytokine in lung tissue.

Animals ; Bronchoalveolar Lavage Fluid ; chemistry ; Decompression Sickness ; Diving ; Lung ; pathology ; Oxygen ; physiology ; Pressure ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo investigate the change of adhesion molecules in the lungs of rats suffered with decompression sickness (DCS).

METHODSMale SD rats were placed in the hyperbaric chamber, the chamber was compressed within 3 minutes to depths of 7 absolute atmosphere (ATA) and held at the designated depth for 60 min, then rapidly decompressed (3 min) to the surface. Rats were observed for signs of DCS after decompression. The brains, hepatis, and lungs were removed at 30 min, 6 h, 24 h post decompression, fixed and stained with hematoxylin eosin for routine histologic analysis. Lung paraffin sections were immunostained for the expression of intercellular adhesion molecule-1 (ICAM-1), E-selectin and major histocompatibility complex class II molecule (MHC-II). 2% evans blue dye in normal saline was injected 30 minutes prior to 6 h, 24 h before decompression. After 30 min, animals were perfused with 0.9% normal saline and lungs were harvested. Evans blue in the plasma was quantified by wavelength spectrophotometric analysis at 620 nm.

RESULTSResults showed that there were hemorrhage and edema changes in the lungs, liver and brain at 30 min post decompression. Compared with control animals maintained at 1 ATA, the levels of E-selectin, ICAM-1 and MHC-II in the lungs of DCS rats were significantly increased post decompression. Compared with control animals, evans blue in the plasma was much higher at 6 h, 24 h post decompression.

CONCLUSIONThe bubble-induced adhesion molecule-mediated endothelial activation may be involved in the pathogenesis of DCS.

Animals ; Brain ; pathology ; Cell Adhesion Molecules ; metabolism ; Decompression Sickness ; metabolism ; E-Selectin ; metabolism ; Endothelium, Vascular ; metabolism ; Genes, MHC Class II ; Intercellular Adhesion Molecule-1 ; metabolism ; Liver ; pathology ; Lung ; metabolism ; pathology ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe the pathological changes in rabbits with spinal cord injury induced by decompression sickness (DCS), and to investigate the role of tumor necrosis factor-alpha (TNF-α) in spinal cord injury induced by DCS.

METHODSRabbits were randomly divided into normal control group, DCS group, and safe decompression group. The rabbit model of DCS was established. Light microscopy, real-time PCR, and immunohistochemical method were used to observe the pathomorphological changes in the thoracolumbar spinal cord and the mRNA and protein expression of TNF-α, respectively. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) was used to observe the apoptosis in the spinal cord.

RESULTSIn the DCS group, cavities formed in the white matter of spinal cord and gliosis occurred around necrotic areas. Moreover, the mRNA and protein expression of TNF-α was significantly higher in the DCS group than in the normal control group and the safe decompression group (P<0.01). The results of TUNEL showed that the number of positive apoptotic cells was significantly larger in the DCS group than in the normal control group and the safe decompression group (P<0.05).

CONCLUSIONApoptosis plays an important role in spinal cord injury induced by DCS. In the early stage of DCS, the massive release of TNF-α initiates apoptosis and contributes to the pathological changes in spinal cord injury induced by DCS.

Animals ; Apoptosis ; Decompression Sickness ; metabolism ; pathology ; Disease Models, Animal ; In Situ Nick-End Labeling ; RNA, Messenger ; Rabbits ; Spinal Cord ; pathology ; Spinal Cord Injuries ; metabolism ; pathology ; Tumor Necrosis Factor-alpha ; metabolism