Effect of blue light on the urinary excretion of tryptophan metabolites in adult heterozygous and homozygous Gunn rats

Tryptophan metabolism along the kynurenine pathway has been studied in male and female heterozygous and homozygous adult Gunn rats after load of amino acid before and after exposure to blue light. The percentage of tryptophan metabolites in each group of rats was slightly higher in females than in males. Before irradiation the excretion of metabolites was larger in male and female heterozygous groups than the corresponding groups of the homozygotes. After irradiation only the groups of male and female heterozygous Gunn rats showed a decrease in the total excretion of the metabolites. Therefore blue light exposure dose not seem to influence the metabolism of tryptophan in homozygous Gunn rats.

Enzyme activities of tryptophan metabolism in heterozygous and homozygous Gunn rats before and after blue light exposure

The effect of light exposure in the enzyme activities, involved in the tryptophan metabolism along the kynurenine pathway, has been studied in male and female adult hetero-and homozygous Gunn rats. Light exposure did not seem to influence these enzyme activities. The groups of non-icteric heterozygotes however showed a higher activity of liver tryptophan pyrrolase than in the groups of icteric homozygotes. Kynureninase activity was similar in all the groups of rats, whereas liver kynurenine aminotransferase activity appeared slightly higher in the groups of male rats with respect to female rats, but no difference existed before and after irradiation. In addition the male heterozygotes showed a higher kynurenine aminotransferase activity in kidneys than the other groups of rats.

Effect of psoralen-induced photodermatitis on tryptophan metabolism in guinea pigs

Tryptophan metabolism after load test, along the kynurenine pathway was studied in guinea pigs, before and during the psoralen-induced photodermatitis. This skin injury, during the acute phase, causes a large increase in urinary excretion of total metabolites and a significant increase of liver tryptophan pyrrolase.

Effect of psoralen-induced photodermatitis on tryptophan metabolism in rats

Tryptophan metabolism 'via kynurenine' has been studied in rats before and after induction of experimental light-conditioned dermatitis with psoralen. Tryptophan load in animals during the acute phase of dermatitis (one day after induction) causes a markedly increased urinary excretion of total metabolites in comparison with that obtained before dermatitis. During this phase of the skin disease tryptophan pyrrolase activity is significantly increased and kynureninase activity significantly decreased in liver in respect to the control animals. Kynurenine aminotransferase activity shows no significant variations in both liver and kidneys. After 6 days of dermatitis, when the skin damage is in repair, both the excretory values of the urinary metabolites after L-tryptophan load and the enzymic activities are similar to those before dermatitis.

Tryptophan metabolism in animals with dermatitis. II) In guinea pigs

Tryptophan load in guinea pigs after induction of a photodermatitis from psoralen caused marked increase of urinary excretion of total metabolites "via kynurenine" in comparison with that obtained before dermatitis. Xanthurenic acid is the metabolite which showed the most increased levels in urine during dermatitis. This dermatitis from furocoumarin caused an alteration of tryptophan metabolism in guinea pigs as well as rats, but species differences in the excretion of metabolites after amino acid load are observed.

Tryptophan metabolism in animals with dermatitis. I) In Rats

Tryptophan metabolism "via kynurenine" after load of amino-acid has been studied in urine of rats before and after induction of experimental light-conditioned dermatitis with psoralen. Tryptophan load in animals during the acute phase of dermatitis (one day after induction) causes a markedly increased urinary excretion of total metabolites in comparison with that obtained before dermatitis. After six days of dermatitis, when the skin damage was in repair, the excretory values after tryptophan load in rats are only slightly increased indicating that the metabolic disturbance is correlated with the skin damage.

Studies on the tryptophan load test in man

Studies on the tryptophan load test were carried out by measuring the urinary excretion of 10 tryptophan metabolites via the kynurenine pathway in 25 healthy men and 20 women after oral L-tryptophan loading with dosages of 2 g. 50 mg/kg or 75 mg/kg body weight. With increasing doses of the amino acid, a difference was found between the male and female groups in the pattern of excretion of the tryptophan metabolites. In both groups, kynurenine and kynurenic acid were the metabolites excreted in the greatest amounts. The results indicate that the most useful loading dose of L-tryptophan for both men and women is 50 mg/kg body weight, as with 2 g L-tryptophan the excretion of the metabolites is too low and varies too much between the two groups of male and female subjects. On the other hand, the load with 75 mg/kg body weight can cause an overloading, particularly in women. No significant variations in the levels of the metabolites were found in the urine of two female subjects at different stages of the menstrual cycle after loading doses of 2 g and 50 mg/kg body weight. On the basis of the determination of the serum tryptophan levels, the period of urine collection was established as 10 h.

[Antibacterial effects of 70 percent denatured ethyl alcohol on hospital bacteria strains]

Data relating to a study of the activity of 70 percent methylated spirits on some bacterial strains isolated in a hospital environment are reported. It was found that the spirit had very little effect over times of 30'' or less, a good bactericidal power for time of 1', and an excellent bactericidal power for times of more than 1'.

[Hyperosmolar coma in diabetes (author's transl)]

Diabetic hyperosmolar coma is characterized by the appearance of a diabetic metabolic state in middle age, lack of ketosis, osmolarity of the plasma greater than 350 milliosmoles, psychic and neurological disturbances, increased occurrence of secondary diseases, arterial thromboses, azotemia. The mortality is 30-60%. The pathogenesis is still uncertain in many respects, consequently the suggestions for therapy are varied. The authors have found the following procedure useful: rapid compensation of sodium deficit, restoration of water balance, normalization of the composition of body fluids by reference to continuous laboratory investigation.

Studies on the kynurenine adminotransferase activity in rat liver and kidney

The kynurenine aminotransferase activity of supernatant and mitochondrial fractions obtained from rat liver and kidney was studied with L-kynurenine and L-3-hydroxykynurenine as substrates. A substrate inhibition with L-kynurenine at concentrations higher than 6-7mM was observed with all four enzyme preparations. This did not happen with L-3-hydroxykynurenine as a substrate. Moreover, the liver mitochondrial enzyme shows a Km for pyridoxal phosphate 2-4 times smaller than the other preparations when assayed with L-3-hydroxykynurenine as a substrate. Therefore, the accumulation of xanthurenic acid and not of kynurenic acid in B6 deficiency could be related both to this high activity of liver mitochondrial kynurenine aminotransferase with L-3-hydroxykynurenine, even at small concentrations of B6, and to substrate inhibition observed with L-kynurenine and not with L-3-hydroxykynurenine.