Cow blood - A superior storage option in forensics?

Given the use of modified blood products (e.g. leucocyte depleted erythrocyte concentrates in SAG-mannitol, dehydrated blood powder, defibrinated blood), drawing blood from conscious animals while minimizing their stress is a good option to obtain blood for bloodstain pattern analysis. Nevertheless, the blood must be well described since individual differences in quality can occur, and storage will influence blood components qualitatively and quantitatively. Cow has been discussed as a suitable source of blood supply, but current data lack hematological and full rheological perspectives. This project includes the respective parameters in combination with passive drip pattern experiments during refrigerated storage in multiple study arms. Cow blood displayed a constant increase in viscosity (at high shear rate: 1000s-1), reflecting the expected reduction in red blood cell (RBC) flexibility. RBCs shrank but remained intact with very few irregular shapes, therefore there was no evidence of hemolysis. Influence of storage on stain size in passive drip pattern experiments with different substrates was minimal. However in cows, it is not hemolysis but an early change in suspension properties that indicates storage lesion. Viscosity (at low shear rate: 1s-1) of some blood samples increased three-fold (peaking at day 14), transitioning sharply to near-Newtonian (almost shear-independent) behavior thereafter. The higher this increase in viscosity, the greater the increase in the number of satellite spatter on glass. In order to ensure high quality simulations in the future, comprehensive rheological analyses to detect gradual changes in blood pseudoplasticity should be implemented in the forensic discipline of bloodstain pattern analysis.

Growth capacity of thermotolerant campylobacters in culture media supplemented with pig and cow blood

In this work 60 thermotolerant Campylobacter strains (37 C. jejuni and 23 C. coli) isolated from the cows, pigs, chickens and ducks (15 strains of each type of animal) were used to establish their growth capacity on media containing cow or swine blood as potential substitutes of sheep or horse blood. The growth capacity was assessed by viable counts on cow and swine blood media, using the modified Miles and Misra method. Campylobacter strains showed better growth in the media supplemented with pig or sheep blood than with cow blood. Thus, the use of pig blood could be a supplement for Campylobacter culture medium, when there was no availability of sheep or horse blood.

Na cidade de Iquitos (Região Amazônica do Peru), tanto o sangue de carneiro quanto o de eqüino, ambos recomendados como suplemento nos meios de cultura para Campylobacter, são difíceis de encontrar. No entanto, sangues de bovino e de suíno são de fácil disponibilidade. Por esta razão, 60 amostras de Campylobacter termotolerantes (37 C. jejuni e 23 C. coli) isoladas de bovinos, suínos, frangos e patos (15 amostras de cada animal) foram utilizadas para estabelecer sua capacidade de crescimento em meios de cultura contendo sangue de bovino ou de suíno como potenciais substitutos do sangue de carneiro ou de eqüino. A capacidade de crescimento foi estabelecida através da contagem de células viáveis utilizando o método de Miles e Misra modificado. Todas as amostras de Campylobacter mostraram melhor crescimento em meios suplementados com sangue de eqüino ou de suíno. Estes resultados permitem propor o uso de sangue de suíno como suplementos em meios de cultura para Campylobacter.