Effects of aflatoxin B1 on the sensitivity of the rat central nervous system to pentobarbital-Na racemate

The immobility time of pentobarbital was prolonged in male rats treated with aflatoxin B1 (AFB1), 2 mg/kg, with maximum on the 3rd day after treatment. It cannot be fully explained by the pharmacokinetic mechanisms. In parallel ED50 of pentobarbital was decreased both in males and females. In males the lethal dose of pentobarbital was decreased by about 30%. The pentobarbital concentration in the brain was increased during the immobility time and at awakening after the ip administration of 40 mg/kg of the drug on the 3rd day after AFB1 treatment with doses of 1 mg/kg and 2 mg/kg po in males and females, respectively. The plasma concentration of pentobarbital was significantly increased in treated males only. The content of unchanged pentobarbital in urine within 24 h after its administration was not high (about 1% in males, 2% in females) and in the AFB1 treated animals it virtually did not change. The elevation of the brain level of barbiturate at the time of awakening in AFB1 treated animals may point to a decreased sensitivity to pentobarbital.

Is DH-ergotoxine the best gerontologicum from the ergot source? Experimental comparison with individual components

The effect of DH-ET (dihydroergotoxine = 33% DH-ergocornine (DH-ECO) + 33% DH-ergocristine (DH-ECS) + + 33% DH-ergokryptine (DH-alfa-ECP: DH-beta-ECP = 2:1 and that of the single DH-derivatives on the retention of 14C-uridine (14C-U) in three parts of the brain tissue, blood plasma and liver tissue was estimated (i.e. radioactivity four hours after ip. adm. of 74kBq X 100 g-1). In young male rats DH-ET and DH-ECO enhanced the retention of 14C-U especially in the parietal cortex In one year old males DH-ECS and DH-alfa-ECP had the greatest effect. As a model of undesired effects the influence on peripheral blood flow in the hind limb of urethanised rats was examined using the perfusion' technics. All substances in the dose of 1 microgram removed epinephrine induced vasoconstriction although they themselves in the dose of 100 micrograms enhanced the perfusion pressure, excepting DH-ECO. All substances diminished the liver blood pool in urethanised rabbits (as norepinephrine does), most efficient being DH-beta-ECP and DH-ECO. On the other hand these substances also slowed the velocity of blood stream. The highest toxicity (LD) of DH-ECS and the lowest one of DH-alfa-ECP was found by an infusion technique. All substances diminished heart frequency but had a variable effect on PQ and QT ECG intervals. Ranging all substances according to their desirable properties from the geriatric viewpoint an index for each substance was calculated. This was most advantageous in the case of DH-alfa-ECP and DH-ECS in contrast to DH-ET and DH-ECO.

[Microlithiasis alveolaris pulmonum. (author's transl)]

A report was made of a long term observation of microlethiasis alveolaris pulmonum in a female patient who died at the age of 53. The rare, etiologically unclear disease is after a long course , always fatal due to right heart failure. This case was unique in that small spotty pulmonary lesions were found radiologically. They presented, a pathognomonic, unmistakable picture for a differential diagnosis of silicosis.

Sex differences in the fate of N-methyl-14C-pethidine in rats

N-Methyl-14C-labeled pethidine was administered intravenously to male and female rats at a dose of 1.25 mg per kg body weight. The amount of 14CO2 (originating from the N-methyl group) in the expired air of female rats was approximately a half of that expired by males. The amounts of radioactive metabolites (probably mainly deesterified products) in the excretions was higher in females. Pethidine levels in liver reach their maximum later, but attain substantially higher levels in females. The shapes of the curves relating pethidine levels to time are identical for blood and brain, but the brain levels are approximately ten times higher. Their course approximates a simple exponential curve in females, but a curve composed of two exponentials in males. Using the COMANSL computer programme and the data for blood levels, a three-compartment model has been established consisting of a central compartment 1, into which the drug was administered, a rapidly exchanging ("shallow") compartment 2, which is in equilibrium with 1, and a slowly exchanging ("deep") compartment 3, from which it is eliminated. Rate constants computed for the entry into and the exit from 1 were similar (0.23 and 0.22) in males; they could not be determined in females (possibly since they were too high). The passage from 1 to 3 was faster in males (0.07) than in females (0.04), the elimination from 3 was substantially faster in males (1.97) than in females (0.33). Faster demethylation in males is attributed to higher demethylation activity of male liver, known from in vitro experiments and faster rate of alternative pathways in females to higher substrate concentration in the liver. Attention is drawn to the considerable sex differences in the distribution of the drug.