ROUTINE PYROGEN TESTING
1 The examination of preparations from large‐scale manufacture for freedom from pyrogens is described. 2 Typical results from the examination of 11. and 0·51. packs of water for injection, glucose‐saline and solution and normal saline solution are presented. 3 Evidence supporting the claim that reduction in the pyrogen levels take place on storage is provided.
Radiation-induced Hyperpyrexia in Rabbits
THE response of rabbits to 25,000–50,000 r. radiation exposure is death within 3–4 hr.1. Even at lower levels of radiation exposure to 600–1,000 r. a shock like death occurs in a few animals within 24–48 hr.2. However, other biological responses which occur more consistently at these lower radiation dose-levels are depression of the white cell count and reduction in bone marrow activity3. This investigation presents evidence that a rise of body temperature is also a regular effect of acute radiation exposure in rabbits.
New method for analysis of enzymatic reactions: Thermolysin-catalyzed synthesis of aspartame precursor
Aspartame is an artificial sweetener which is 200 times sweeter than sucrose. A precursor of aspartame, N-(benzyloxycarbonyl)-l-aspartyl-l-phenylalanine methyl ester (Z-APM) was synthesized and hydrolyzed with thermolysin in an aqueous monophasic system. Graphical plotting methods and/or nonlinear regression have been used to analyze enzymatic reactions because of the nonlinearity of enzymatic rate equations. There are, however, problems: the former require accurate measurement of the initial reaction rate and the latter gives no analytical information. The authors proposed a method to solve the nonlinear enzymatic rate equations with respect to the concentration of a product with the Taylor expansion, especially for the reversible Theorell-Chance mechanism (Murakami, Y., Hirata, M., and Hirata, A., J. Ferment. Bioeng., 82, 246–252, 1996). This solution, however, is complex for practical use. In this paper, a simpler solution to explain the thermolysin-catalyzed synthesis of Z-APM is obtained. New methods to determine the kinetic parameters, especially for the reversible Theorell-Chance mechanism, based on the approximated solution are proposed. The results calculated using the obtained kinetic parameters can satisfactorily explain the experimental results, which demonstrates the effectiveness of the proposed analysis. We must know the relation between the concentrations of substrates and a product, and accurately evaluate of the result obtained using Taylor expansion when we determine the kinetic parameters using our newly developed methods. The methods to determine the kinetic parameters of the reversible Theorell-Chance mechanism described in this paper is, however, expected to be applied to general enzymatic reactions.