Chemically sensitized erythrocytes for hemagglutination reactions.

The use of chemically modified indicator erythrocytes for hemagglutination reactions can result in increased sensitivity. Treatment of erythrocytes with polyvinylpyrrolidone (PVP) or dextran T40 (10% weight/volume) induces changes in the cell surface in the form of extensions and blebbing, thereby increasing the surface area. These sensitized cells can be used in forensic science when detection or quantitation of erythrocyte surface reacting antibodies is important. The effect of altering membrane lipid fluidity on erythrocyte surface antigens has also been investigated. Treatment of cells with a reagent that increases the membrane ratio of cholesterol to phospholipid results in enhanced hemagglutination capacity despite the lack of extensive spiculation.     

Recovery of human remains after shark attack

Two cases of fatal shark attack are reported where the only tissues recovered were fragments of lung. Case 1: An 18-year-old male who was in the sea behind a boat was observed by friends to be taken by a great white shark (Carcharodon carcharias). The shark dragged him under the water and then, with a second shark, dismembered the body. Witnesses noted a large amount of blood and unrecognizable body parts coming to the surface. The only tissues recovered despite an intensive beach and sea search were 2 fragments of lung. Case 2: A 19-year-old male was attacked by a great white shark while diving. A witness saw the shark swim away with the victim's body in its mouth. Again, despite intensive beach and sea searches, the only tissue recovered was a single piece of lung, along with pieces of wetsuit and diving equipment. These cases indicate that the only tissue to escape being consumed or lost in fatal shark attacks, where there is a significant attack with dismemberment and disruption of the integrity of the body, may be lung. The buoyancy of aerated pulmonary tissue ensures that it rises quickly to the surface, where it may be recovered by searchers soon after the attack. Aeration of the lung would be in keeping with death from trauma rather than from drowning and may be a useful marker in unwitnessed deaths to separate ante- from postmortem injury, using only relatively small amounts of tissues. Early organ recovery enhances the identification of human tissues as the extent of morphologic alterations by putrefactive processes and sea scavengers will have been minimized. DNA testing is also possible on such recovered fragments, enabling confirmation of the identity of the victim.     

The influence of site of collection on postmortem morphine concentrations in heroin overdose victims

When assaying for postmortem morphine concentration, significant site sampling variability exists between central and peripheral sampling sites and even within sampling regions of the body. To study the variation, 76 suspected heroin overdoses were identified. Each had femoral artery (FA) and vein (FV), left and right ventricle and pooled heart blood samples obtained at autopsy. Forty-four tested positive for morphine. Morphine concentrations were determined by gas chromatography/mass spectrometry, with sampling site differences reported as log-transformed ratios and compared by signed rank test.The mean FA to FV ratio for total morphine was 1.2 (range 0-4.5). The ratio for left heart to right heart total morphine was 1.1 (range 0.4-3.2). Left ventricular to FV total morphine ratio was 2.0 (range 0.6-6.9). In these opioid overdose deaths, FA and FV morphine concentrations are usually similar, although up to 4.5-fold differences were noted. Centrally obtained morphine concentrations are on average twice as high compared with peripheral morphine concentrations. Left and right ventricular morphine concentrations were usually similar, although up to 3.2-fold differences were noted (left side higher).