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Biomedical subjects

B Marescau

Publications and source records attributed to B Marescau.

67 records · Page 4Linked to original sources
PubMed1986

Effects of emotional stress on E1-mouse convulsions, and their biochemical background.

Emotional stress markedly inhibited E1 mouse convulsions. Norepinephrine and dopamine levels in E1 mouse brain were hardly affected by stress, though a marked decrease in norepinephrine and dopamine levels was observed in the ddY mouse brain. The serotonin levels decreased in the E1 mouse brain in the same degree as in the ddY mouse brain. These findings suggest that the serotonergic system is involved in the inhibition of E1 mouse convulsions, through an enhanced serotonin release in the brain brought on by the emotional stress. Noradrenergic and dopaminergic systems may also be involved.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1986

Comparative study of guanidino compounds in serum and brain of mouse, rat, rabbit, and man.

The levels of 12 guanidino compounds were determined in the serum and brain of mouse, rat, rabbit, and man using cation-exchange column chromatography with the fluorescence ninhydrin detection method. A comparative study of these compounds was made in the four groups studied, for serum and brain. In rabbit and man the different guanidino compounds were also determined in various brain regions. This study provides basic analytical data that could facilitate the interpretation of further biochemical and neurochemical studies dealing with guanidino compounds that are identified as being toxins in hyperargininemia and uremia.

Animals↗
PubMed1986

Guanidino compounds in serum and brain of audiogenically sensitive rats.

The levels of 12 guanidino compounds were determined in serum and brain of audiogenically sensitive rats with and without seizures. During audiogenic seizures the serum levels of creatine are significantly decreased, while those of guanidinoacetic acid, N-alpha-acetylarginine, creatinine, gamma-guanidinobutyric acid, arginine, guanidine and methylguanidine are significantly increased. In brain only creatinine and N-alpha-acetylarginine are markedly increased during seizure. These data demonstrate noticeable modifications of the levels of guanidino compounds in the blood during audiogenic seizure and also, in parallel, a creatinine increase in serum and brain.

Animals↗
PubMed1985

Guanidino compounds in plasma, urine and cerebrospinal fluid of hyperargininemic patients during therapy.

The concentrations of guanidino compounds were determined in urine, plasma and cerebrospinal fluid of two patients with hyperargininemia during dietary therapy. alpha-Keto-delta-guanidinovaleric acid, N-alpha-acetylarginine, argininic acid and gamma-guanidinobutyric acid were increased in urine. In plasma, these compounds together with creatine, guanidinoacetic acid, arginine and homoarginine were also increased. In cerebrospinal fluid, only arginine, homoarginine and argininic acid were increased. Trace amounts of alpha-keto-delta-guanidinovaleric acid were found in cerebrospinal fluid of the patient treated with only a low-arginine diet. The concentrations of guanidinosuccinic acid are decreased in urine, plasma and cerebrospinal fluid. During a low-arginine diet, together with sodium benzoate therapy, the plasma and cerebrospinal fluid arginine values returned to normal. There was also a normalization of plasma guanidinoacetic acid and a marked decrease in plasma N-alpha-acetylarginine and argininic acid.

Adolescent↗
PubMed1984

Hyperargininemia: the rat as a model for the human disease and the comparative response to enzyme replacement therapy with free arginase and arginase-loaded erythrocytes in vivo.

Rat erythrocytes lack arginase as do the erythrocytes of human homozygote patients with hyperargininemia due to arginase deficiency. The rat has physiological liver arginase activity and plasma arginine and ornithine levels between the homozygotes and the heterozygotes with hyperargininemia. In rats, one injection of free arginase induces a transient exogenous arginase effect which is abolished after 24 hr. One injection of isoionic arginase-loaded erythrocytes provokes an exogenous arginase effect in physiological "hyperargininemic" rats and pathological "hyperargininemic"-made rats for at least 8 and 5 days respectively. The very transient response in vivo to exogenous free arginase can be considerably prolonged by entrapment of the arginase in isoionic prepared erythrocytes.

Amino Acid Metabolism, Inborn Errors↗
PubMed1982

Measurement of arginine transport in human erythrocytes using their intrinsic arginase activity: implications for the treatment of familial hyperargininemia.

A procedure making use of the intracellular arginase activity has been developed for measuring the transport of arginine across the human erythrocyte membrane. (1) The arginine translocation is carrier mediated with simple Michaelis-Menten kinetics, showing one high affinity, low capacity transport system characterized by a half saturation constant KT of 0.177 +/- 0.036 mmol/1, and a maximum velocity VT of 0.332 +/- 0.068 mumol X h-1 X ml-1 cells. (2) Competition experiments with lysine, ornithine and leucine indicated that the arginine transport system in specific for dibasic amino acids. (3) The value calculated for the intracellular arginine concentration agreed well with the values obtained by independent methods. (4) The low arginine transport rate of human erythrocytes can explain the failure to lower the hyperargininemia in familial hyperargininemia by blood transfusion with normal arginase-containing erythrocytes.

Arginase↗
PubMed1981

Isolation and identification of 2-oxo-5-guanidinovaleric acid in urine of patients with hyperargininaemia by chromatography and gas chromatography/mass spectrometry.

An unknown guanidino-positive peak has been identified in urines of three sisters affected with hyperargininaemia. Identification was made on the basis of its similarity with the liquid and thin-layer chromatographic characteristics of enzymatically synthesized 2-oxo-5-guanidinovaleric acid. Identification was also made by combined gas chromatography-mass spectrometry of the unknown compound peak. The synthesis of enzymatically formed 2-oxo-5-guanidinovaleric acid was controlled by nuclear magnetic resonance and combined gas chromatography-mass spectrometry.

Amino Acid Metabolism, Inborn Errors↗
PubMed1979

Arginase and free amino acids in hyperargininemia: leukocyte arginine as a diagnostic parameter for heterozygotes.

Arginase activity and free amino acids were measured in plasma, erythrocytes and leukocytes of patients with hyperargininemia and in controls. There is no arginase activity in the leukocytes and erythrocytes of homozygous patients; in heterozygotes it is normal to low. The activity is 50 to 100 times higher in leukocytes than in erythrocytes. In controls as well as in patients and heterozygotes, the amino acid concentrations are higher in leukocytes than in plasma and erythrocytes. In addition to the increased arginine in the three blood compartments (the result of an arginase deficiency), there is also an obvious decrease of aspartic acid in the erythrocytes of the patients. The arginine concentration in leukocytes of heterozygotes is as high as in homozygotes and can therefore be used as a diagnostic parameter for heterozygotes.

Amino Acid Metabolism, Inborn Errors↗