conditions. Without additional data this small difference in the rate of decomposition does not allow us to conclude that the oxidized form further stabilizes the Cr(IV) species.O'Brien and Ozolins14 noted that at higher pH the dominant Cr(V) complexes decayed to Cr(III) products through a two-term rate law, a first-order process (first order in Cr(V); rate constant = 1.5 X 10"1 23 4s'1) and a second-order process (first order in each Cr(V) and GSH; rate constant = 9.1 X "3 M'1 s'1). At higher pH it is likely that the Cr(V) species undergoes parallel internal electron transfer and a direct reaction by a GSH molecule to form the Cr(IV) complex. This Cr(IV) complex is then rapidly reduced to Cr(III) products, in accord with our rate data showing that the second-order rate constant for the chromium(IV) decomposition (k = 0.13 M'1 s"1) in our system is at least 10 times larger than that for (k = 9.1 X 10"3 M'1 s'1) the decomposition of Cr(V) complexes.14 Acknowledgment. Funding of this research by the Kent State University Research Council is gratefully acknowledged. We thank Professors Wetterhahn and Gould for valuable discussions and Mr. Sutisak Kitareewan for helping with the recording of "time of fly" spectra during the HPLC separations. We are also grateful to reviewer no. 3 for incisive comments and helping with stylistic changes of the manuscript.

There is no association between the magnitude of metabolic acidosis, quantified by the base excess, and mortality in children with shock. Hyperlactataemia, but not elevation of 'unmeasured' anions, is predictive of a poor outcome.

Cases with abnormal liver function tests, Bantu blood donors, neonates, Caucasian patients with primary cancer of the liver, and male Bantu mine workers with primary cancer of the liver have been investigated by means of a quantitative alpha‐feto‐protein (AFP) immunodiffusion assay. No false‐positive AFP tests have occurred, and 78% of primary liver cancer patients are positive. More sensitive tests are capable of increasing the positivity rate still further.

Puff adder venom contains a protease capable of cleaving the gamma-chain of cross-linked D-dimer, derived from the plasmin digestion of fibrin, into apparently symmetrical monomers. The cross-linked gamma-chains are separated in the process without apparent loss of mass and without loss of the substituent at the glutamine cross-link site, if fluorescent D-dimer (the lysine analogue dansylcadaverine used as substituent) is used as substrate [Purves, L. R., Purves, M., Lindsey, G. G., & Linton, N. J. (1986) S. Afr. J. Sci. 82, 30]. The gamma-chain from puff adder venom digested D-monomer was isolated and cleaved by cyanogen bromide, and the carboxy-terminal peptide was isolated and sequenced. The carboxy-terminal peptide composition indicated a lower content of histidine, leucine, and glycine than expected. Manual microsequencing by gas-phase Edman degradation demonstrated that two amino-terminal ends were present. By use of the known sequence of the human fibrinogen gamma-chain, the sequencing data could be resolved into a dipeptide cross-linked between lysine-406 and either glutamine-398 or -399 (residues 6 and 13 or 14 from the carboxy-terminal end of the gamma-chain) with the loss of residues 401-404 that occur between the cross-link sites of both antiparallel cross-linked gamma-chains. D-dimer is therefore separated into monomers by cleavage of the gamma-chain between the cross-link sites. Two symmetrical fragments are produced consisting of a cross-linked dipeptide with the loss of four amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)