Interferon-gamma induced by administration of recombinant interleukin-2 to patients with cancer: kinetics, dose dependence, and correlation with physiological and therapeutic response.

The administration of recombinant interleukin-2 as an i.v. bolus at dose levels of from 1 to 30 MIU/m2 to patients with cancer induces easily measurable serum interferon-gamma levels of 1 to 500 U/ml. After a lag of 1 h, interferon-gamma rises to a maximum at 4 h and then slowly decreases. The peak values are poorly correlated with the dose of interleukin-2, and thus must be also be dependent on other factors. Successive administration of interleukin-2 typically increases the peak level of interferon-gamma fourfold, but does not diminish the lag period. Peak levels of interferon-gamma are also increased by concurrent administration of interferon-beta with interleukin-2. Continuous i.v. infusion of 1.5 to 20 MIU/m2 of interleukin-2/day results in interferon-gamma levels of 1 to 7 U/ml. Hypotension, which is characteristically associated with interleukin-2 administration, is correlated with interferon-gamma levels in only some patients. There was no apparent correlation between tumor regression and serum interferon-gamma levels.

DMSO is a substrate for chloroperoxidase.

Dimethyl sulfoxide has been used as a nonaqueous organic solvent in haloperoxidase reactions. However, it has been found that this solvent is not inert under chloroperoxidase reaction conditions, forming the halosulfoxide, the sulfone, and the halosulfone. The biological significance of this finding is briefly discussed.

Novel haloperoxidase reaction: synthesis of dihalogenated products.

The enzymatic synthesis of vicinal, dihalogenated products from alkenes and alkynes is described. The enzymatic reaction required an alkene or alkyne, dilute hydrogen peroxide, a haloperoxidase, and molar amounts of halide ions. Vicinal dichloro, dibromo, and diiodo products could be formed. A hydroxyl group on the carbon adjacent to the carbon-carbon double or triple bond lowered the halide ion concentration needed to produce the dihalo product. This reaction offers one explanation for the origin of natural, vicinal, dihalogenated products, such as those found frequently in marine microogranisms.

Production of Epoxides from alpha,beta-Halohydrins by Flavobacterium sp.

The relative activity of Flavobacterium whole cells on the enzymatic synthesis of epoxides from alpha,beta-chlorohydrins, -bromohydrins, and -iodohydrins is described.

Haloperoxidases: Enzymatic Synthesis of alpha,beta-Halohydrins from Gaseous Alkenes.

The enzymatic synthesis of alpha,beta-halohydrins from gaseous alkenes is described. The enzymatic reaction required an alkene, a halide ion, dilute hydrogen peroxide, and a haloperoxidase enzyme. A wide range of gaseous alkenes were suitable for this reaction, including those containing isolated, conjugated, and cumulative carbon-carbon double bonds. Chlorohydrins, bromohydrins, and iodohydrins could be formed. The combining of this enzymatic synthesis with a previously described enzymatic synthesis of epoxides from alpha,beta-halohydrins provides an alternate pathway, other than the well-known enzymatic direct epoxidation pathway, from alkene to an epoxide.