S. Barbi

Plasma and cerebrospinal fluid free amino acid concentration in post-traumatic cerebral oedema in patients with shock.

Abstract The concentrations of free amino acids in plasma and cerebrospinal fluid (CSF) in 15 patients with post-traumatic cerebral oedema with hyperventilatory syndrome have been analyzed. Hypotheses are proffered to interpret the observed alterations of amino acids cerebral metabolism in this condition.

Amino acid distribution in guinea pig plasma, experimental hypoxia

An experimental study of 150 guinea pigs has been carried out to analyze the amino acid pattern in plasma, cerebrospinal fluid and brain tissue in acute hypoxia. The distribution of these compounds changed, and hypotheses about particular cerebral metabolic pathways involved are presented.

Intravenous sodium lactate administration in respiratory alkalosis secondary to severe brain injuries.

In acute cerebrovascular accidents the uptake of lactate by the brain tissue is enhanced, possibly in an attempt to buffer the increased local lactic acidosis. In this paper the results obtained by the administration of the lactate in 78 cases of hyperventilatory syndromes secondary to acute brain injuries, and the biochemistry of the cerebrospinal fluid and blood, are reported.

The amino acid cerebral pool after toxic doses of lidocaine and mexiletine. An experimental study on guinea pigs.

Lidocaine and Mexiletine are two anti-arrhythmic drugs which when administered in toxic doses cause alterations in the central nervous system (convulsions, tremors, coma). An experimental study was carried out to clarify some neurological side-effects caused by these two drugs, by studying the variations of the brain amino acid pool. With Lidocaine one can observe an increase of phenyl-alanine and tyrosine, a decrease of glycine, GABA, alanine, aspartate and glutamate, while taurine and ammonia showed no significant changes. After Mexiletine one can observe an increase of ammonia, a decrease of GABA, glutamine, glycine and alanine, while glutamate, taurine, phenyl-alanine and tyrosine remain within normal values. In conclusion, on the basis of the data obtained by comparing the two drugs, one could say that Lidocaine has a greater interference on the catecholaminic precursors which are little influenced by Mexiletine. For the rest, the data obtained are practically super- imposable .

Concentrations of free amino acids in plasma and brain in experimental coma due to flunitrazepan in guinea pigs

Abstract The concentrations of free amino acids in plasma and brain after Flunitrazepam administration have been analyzed in guinea pigs. The changes observed indicate effects on the catecholaminergic, citrate and glutamate metabolic pathways.

An electronic system of infrared spectral data for toxicological analysis

Abstract A large number of non-volatile poisons have been analyzed by infrared spectroscopy and spectral indices have been stored as standards. Comparison of the spectra of unknown samples with the standard spectra allows identification of the unknown samples. This comparison is carried out by computer.

Cerebral and systemic amino acid metabolism in experimental acute amphetamine poisoning in guinea pigs

Protein catabolism, as measured by plasma amino acids is increased by amphetamine injection (15 mg/kg body wt) administered to 10 adult male guinea pigs. Changes in the cerebrospinal fluid were less marked than those in the plasma. The amphetamine seemed to inhibit the enzymes of the metabolic pathways that use amino acids.

Concentrations of plasma and cerebrospinal fluidfree amino acids in hypercapnic coma and acute respiratory failure

A comparison between the concentrations of free amino acids in the plasma and cerebrospinal fluid (CSF) in cases of hypercapnic coma and acute respiratory failure has been made. Hypotheses are formulated to interpret the observed changes in the cerebral metabolism of amino acids in these pathological conditions.

Free amino acids in plasma and erythrocytes during and after cardiopulmonary by-pass in open-heart surgery.

The concentrations in plasma and erythrocytes of free amino acids before, during and after cardiopulmonary by-pass have been determined. During by-pass and the early postoperative period the total alpha-amino nitrogen decreased, mainly because of changes in glucogenic amino acids; ketogenic amino acids, on the other hand, increased. The phenylalanine/tyrosine ratio was markedly increased in all cases.

The brain amino acid pattern in experimental coma due to phenytoin in guinea pigs

An experimental study was carried out on 50 guinea pigs to evaluate the amino acid pattern in the whole brain after a toxic dose of phenytoin (1 g . kg-1 body wt). One group of 25 guinea pigs was treated with the drug which made them comatose, and their brains removed by craniotomy and frozen in liquid nitrogen; 25 guinea pigs were used as a control group. The brain amino acid pattern was determined by ion-exchange chromatography. All the amino acids, except threonine and methionine, decreased. Hypotheses about the particular cerebral metabolic pathways involved are discussed.