The assay of endotoxin by intravenous injection of lead acetate-treated mice.

A new intravenous endotoxin assay method (i.v. method) for the determination of very small amounts of endotoxin was studied in mice pre-treated intraperitoneally with lead acetate and was compared with an earlier intraperitoneal (i.p.) method in which both endotoxin and lead acetate were administered by the i.p. route. Linear dose-response relationships were obtained for both the i.v. and i.p. methods between logarithmic doses of endotoxin and the responses measured as body weight ratios on the first day. The range of the linearity was longer in the i.v. method than that in the i.p. method. In the i.v. method, linearity extended to much smaller doses of endotoxin than in the i.p. method. The slope of the dose-response line obtained by the i.v. method was flatter than that obtained by the i.p. method. The minimum detectable dose defined as the smallest dose of endotoxin producing a mean response statistically distinguishable from that of the control was in the nanogram order and smaller than that obtained by the i.p. method. Therefore the i.v. method may be more suitable than the i.p. method for detection of very small amounts of endotoxin. The non-parallelism of the dose-response lines obtained in lead acetate-treated and untreated mice was demonstrated in the i.v. method as well as in the i.p. method.

Dissociation of the enhancing effects of lead acetate on lethal and body-weight-decreasing activities of endotoxin by the administration route.

The enhancing effects of lead acetate on the lethal and the body-weight-decreasing activities of endotoxin in mice with different combinations of the administration routes. The effect of lead acetate on the lethality was shown by iv administration, but not by ip administration. The body-weight-decreasing activity of endotoxin was enhanced by ip administration of lead acetate but not by iv administration. In any case, the route of administration of endotoxin was not concerned with the enhancement by lead acetate.

Assay in mice for minute amounts of endotoxin by pre-administration of lead acetate.

The enhancing effect of pre-administration of lead acetate on the body-weight decrease due to endotoxin was studied in mice for the purpose of developing a method for determination of minute amounts of endotoxin. By adoption of the body-weight ratio on the first day after endotoxin administration (BWR1) as a response, the linear regression lines of the dose-response were demonstrated over a wide range of log doses of several different endotoxin preparations tested. By use of these linear regression equations experimentally obtained, the minimum detectable dose was calculated. The minimum detectable dose was defined as a dose of an endotoxin preparation producing a mean body-weight response statistically distinguishable from that of the control. The doses obtained were mostly in nanogram order. The magnitude of the enhancement brought about by the lead treatment was estimated at about 40 to 100 times.

Enhancement by lead acetate of body weight-decreasing activity of endotoxin: quantitative comparisons of some administration methods of lead acetate.

The body weight-decreasing effect of sublethal doses of endotoxin was enhanced in mice administered with such an amount of lead acetate that had no effect by itself on body weight. The enhancing effects of administration of lead acetate prior to, simultaneously with and after endotoxin administration were analyzed and compared by statistical methods. Linear dose-response relation between logarithmic doses of endotoxin and body weight-decreasing responses was obtained over a wide range of endotoxin doses with a constant dose of lead acetate. The non-parallelism between two dose-response lines obtained in lead acetate-treated and control mice was not denied. The relation of the two lines indicated that the more minute the dose of endotoxin, the more intense the enhancing effect of lead acetate appearing in the treated mice within certain limits of minute doses of endotoxin. These results were common in the three administration methods of lead acetate and can be applied to detection of minute doses of endotoxin. It was suggested that the pre-administration method of lead acetate was more suitable for detection of endotoxin than the other methods.

Japanese minimum requirements for albumin preparations: recent amendments and current problems.

The following amendments have been introduced to the Minimum Requirements for Human Serum Albumin (HSA) and Plasma Protein Fraction (PPF): 1) The upper limit of sodium content was fixed at 3.7 mg/ml; 2) test for chloride content was introduced; 3) sodium and chloride contents were required to be stated on the label; 4) use of zone electrophoresis was introduced in addition to the free-boundary electrophoresis; and 5) albumin content in HSA was lowered from 97% to 96%. Moreover, current problems in quality control which may require further amendments were discussed, namely: 1) limulus amoebocyte lysate test to replace or supplement the pyrogen test in rabbits; 2) attempt of quantitative expression of visual turbidity; 3) establishment of reference A and B blood group substances; 4) gel permeation analysis and scanning at 370-800 nm; and 5) test for prekallikrein activator (PKA).

Endotoxemia and adrenaline-hyperreactive death in mice.

Mice given i.v. a sublethal dose of endotoxin in advance died with shock-like symptoms on administration of sublethal adrenaline dose. The lethal adrenaline-hyperreaction induced by endotoxin appeared gradually within a few h, showed maximum response after several h and almost disappeared 24 h after endotoxin administration.