Sodium hyaluronate (HA) is widely distributed in extracellular matrixes and can play a role in orchestrating cell function. Consequently, many investigators have looked at the effect of exogenous HA on cell behavior in vitro. HA can be isolated from several sources (e.g., bacterial, rooster comb, umbilical cord) and therefore can possess diverse impurities. This current study compares the measured impurities and the differences in biological activity between HA preparations from these sources. It was demonstrated that nucleic acid and protein content was highest in human umbilical cord and bovine vitreous HA and was low in bacterial and rooster comb HA. Macrophages exposed to human umbilical cord HA produced significantly higher amounts of TNF-alpha relative to control or bacterial-derived HA. These results indicate that the source of HA should be considered due to differences in the amounts and types of contaminants that could lead to widely different behaviors in vitro and in vivo.

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SUMMARY. Leptospira interrogans serovars pomona and hardjo were adapted to grow in a chemically-defined, protein-free (PF) medium. Formolised monovalent vaccines of serovars pomona and hardjo and a bivalent mixture of the two were prepared from PF cultures. Live P F cultures and the vaccine preparations retained their agglutinating antigens and their immunogenicity when tested in rabbits and guineapigs. The vaccines were not pyrogenic and dermal reactions were slight.

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