Establishment of a normal reference range for adenosine deaminase in plasma of healthy Saudis using the continuous spectrophotometric method.

The level of adenosine deaminase (EC. 3.5.4.4), was estimated in plasma of 389 healthy males and 493 healthy females in order to establish a normal reference range for Saudis. Using the continuous spectrophotometric method, the reference ranges were calculated in two ways using the mean +/- 2 SD and the 2.5th - 97.5th percentile value methods. In both methods of calculation, a slightly higher range was observed for children as compared to adults. The method of 2.5th - 97.5th percentile values brought almost all of our subjects within the recommended range of 11.5 - 25 U/l. In the current study, the normal range for adenosine deaminase totalled 15.0 - 23.2, 14.8 - 23.6, 15.0 - 23.0 and 16.7 - 24.6 U/l for the overall population, all males, females, and children, respectively. The ranges are discussed in the light of significantly different results obtained by the two calculation methods and recommendation of an appropriate method for healthy Saudis, namely the 2.5th - 97.5th percentile values. The choice of the Ellis and Goldberg kinetic continous monitoring method for the estimation of plasma ADA levels in the current investigation is also hereby justified.

The effect of crude Cerastes cerastes gasperetti venom on the activity of key metabolic enzymes in cultured human fibroblasts.

Cultured human fibroblasts were used to study the effect of a crude extract of Cerastes cerastes gasperetti venom on the activity of a profile of key enzymes of metabolism. A single concentration of the crude venom was incubated with confluent fibroblasts established from six normal subjects for a period of three hours. A dramatic reduction in the specific activities of glucose and glycogen degradative enzymes was observed (23.7 +/- 3.9%, 36.3 +/- 8.7% and 71.1 +/- 5.7% of control for citrate synthase, glucose-6-phosphate and phosphofructokinase respectively). Furthermore, the specific activity of creatine kinase was doubled. No significant change in activity of three transaminases was noticed. Incubation of the same concentration of venom for the same period of time with serum did not result in any change in the activity of the enzymes studied. It is suggested that the cells mobilize stored phosphocreatine for the production of adenosine triphosphate (ATP) to compensate for the reduced rate of sugar catabolism. Furthermore, it is hereby suggested that the effects noticed on the enzyme activities are not directed at the enzyme protein itself, but are of mediated nature.