Total Α-amino Research Articles

Serum total lipids and lipid fractions in marasmus.

Plasma total lipid, lipid fractions, total protein protein fractions and α-amino nitrogen were studied in 30 cases of marasmic protein-calorie malnutrition and 10 control cases. Repeated determinations were done after the patients had gained at least 10% of their admission weight. With the exception of lipoproteins and phospholipids, no major differences existed in plasma lipid and lipid fractions in cases of marasmus at admission and in the recovery phase.

Amino acid levels in hydrazine-treated rats

Tyrosine-loaded rats, injected with hydrazine, showed a marked elevation of plasma and brain tyrosine levels above that of a comparable tyrosine-loaded control group. An additional control group receiving only hydrazine had plasma and brain tyrosine levels greater than the tyrosine-loaded controls. The subsequent measurement of total α-amino nitrogen levels demonstrated that hydrazine injections, with or without tyrosine loading, resulted in approximately a 3-fold increase in plasma α-amino nitrogen levels when measured 3 hours after treatment. Eighteen hours after hydrazine injection plasma, brain, and liver α-amino acid levels were still above control values. Such findings are consistent with the known in vitro inhibition of amino acid metabolism by hydrazine, due to binding of the coenzyme pyridoxal phosphate.

Free Amino Acids, Ammonia and Urea Concentrations in the Blood Plasma of Starved Lambs

The effect of short periods of starvation on the free amino acid, ammonia and urea concentrations in blood plasma of Dorset Horn × Border Leicester-Merino lambs was studied in 3 age groups between 14 and 20 weeks of age. They were subjected to one of the following treatments: 1) fed a maintenance ration for 3 weeks; 2) fed a maintenance ration for 2 weeks and starved for 1 week; or 3) totally starved for 3 weeks. The concentration of free amino acids, ammonia and urea were determined in the blood plasma at the time of killing. Starvation for 3 weeks resulted in a significantly lower concentration of total α-amino nitrogen in the plasma when compared with the control fed lambs. The individual amino acids which were significantly lower were threonine, glutamic acid, alanine, valine, isoleucine and leucine and also urea. The concentration of lysine in the blood plasma was significantly higher in the starved lambs.

GAMMA-AMINOBUTYRIC ACID LEVELS IN THE BRAIN OF RATS EXPOSED TO OXYGEN AT HIGH PRESSURES

Rats were exposed to 100% oxygen at a pressure of 6 atmospheres absolute for 33 minutes. The surviving animals were assigned to one of three groups: (a) animals suffering severe convulsions during exposure, (b) animals suffering mild convulsions during exposure, (c) animals in which no convulsions were observed during exposure. The concentration of gamma-aminobutyric acid (GABA) in the brains of rats in all groups was lower than in unexposed rats, reductions of 35%, 27%, and 19% in GABA concentration being observed in groups (a), (b), and (c) respectively. Only a few minutes' exposure to oxygen at high pressure was necessary to cause a significant decrease in GABA concentration. Exposure either to air at high pressure or to 100% oxygen at ambient pressure produced no reduction in GABA levels. Although the GABA concentration in the brain increased markedly within 1 hour after the end of the 33-minute exposure to oxygen at 6 atm pressure it was still somewhat below the levels found in unexposed animals. No significant change in GABA levels was observed during a further 2 hours of recovery time. In the case of rats exposed for only a short period of time, however, a complete return to normal was observed within the first hour. The levels of glutamic acid, aspartic acid, and total α-amino acids in the brain were not altered by exposure to oxygen at high pressure.

GAMMA-AMINOBUTYRIC ACID LEVELS IN THE BRAIN OF RATS EXPOSED TO OXYGEN AT HIGH PRESSURES

Rats were exposed to 100% oxygen at a pressure of 6 atmospheres absolute for 33 minutes. The surviving animals were assigned to one of three groups: (a) animals suffering severe convulsions during exposure, (b) animals suffering mild convulsions during exposure, (c) animals in which no convulsions were observed during exposure. The concentration of gamma-aminobutyric acid (GABA) in the brains of rats in all groups was lower than in unexposed rats, reductions of 35%, 27%, and 19% in GABA concentration being observed in groups (a), (b), and (c) respectively. Only a few minutes' exposure to oxygen at high pressure was necessary to cause a significant decrease in GABA concentration. Exposure either to air at high pressure or to 100% oxygen at ambient pressure produced no reduction in GABA levels. Although the GABA concentration in the brain increased markedly within 1 hour after the end of the 33-minute exposure to oxygen at 6 atm pressure it was still somewhat below the levels found in unexposed animals. No significant change in GABA levels was observed during a further 2 hours of recovery time. In the case of rats exposed for only a short period of time, however, a complete return to normal was observed within the first hour. The levels of glutamic acid, aspartic acid, and total α-amino acids in the brain were not altered by exposure to oxygen at high pressure.

A rapid screening test for determination of total α-amino acids in urine and serum

A simple ninhydrin method is described for the determination of total α-amino acids in urine and serum. The method is suitable for screening tests; the samples are prepared rapidly and placed on alkaline filter papers, which can be stored and developed later.

Chemical Characteristics of Salted Cod

A study has been made of the formation of decomposition products in three different types of salted codfish. The total volatile acids, trimethylamine, ammonia and free α-amino acids were determined on 50 samples of each type of salted fish. The total volatile acids and trimethylamine were found to be chemical indices which enable a clear differentiation between light- and heavy-salted cures. The presence of large quantities of these two decomposition products is typical of light-salted cures, especially of the "Gaspé cure".The influence of the degree of salt saturation in the brine and in the muscle itself during processing, on formation of decomposition products, is discussed.

The hydrolysis of insulin and human serum albumin in dilute hydrochloric acid

Insulin, which contains two internally situated asparagine residues and one C-terminal asparagine residue, was used as a model compound to study the specificity of protein hydrolysis in dilute hydrochloric acid. Changes occurring in aspartic acid, ammonia (arising from the hydrolysis of amide bonds), and α-amino nitrogen were determined throughout the course of hydrolysis. The results indicated that quantitative cleavage of asparagine and glutamine amide bonds and aspartic acid peptide bonds occurred. Determinations of N-terminal residues in insulin partial hydrolyzates revealed that cleavage of some serine and threonine peptide bonds occurred, but no other unexpected N-terminal residues were noted. The fragmentation in dilute acid of the proteins of the albumin fraction of human serum was studied by measuring changes in the total α-amino nitrogen content of four subfractions of albumin partial hydrolyzates, and additional evidence concerning the specificity of dilute acid hydrolysis was obtained. A peptide was isolated in good yield from an albumin dilute acid hydrolyzate and was partially characterized.

A study of the free amino acids in sweat from patients with cystic fibrosis.

There has been a paucity of work on the amino acid composition of sweat in healthy and sick children. In cystic fibrosis of the pancreas the sweat glands excrete sodium and chloride in a concentration far above that found in a control group. The potassium is also elevated but to less extent.1,2In view of this dysfunction of the sweat glands in cystic fibrosis it appeared reasonable to investigate other components of sweat. Unpublished work from this laboratory indicates that other constituents in sweat from patients with cystic fibrosis, such as urea, lactic acid, citric acid, sulfate, and phosphorus, do not differ from the normal.3It is intended in this paper to present our findings of the amino acid distribution and of the total α-amino nitrogen concentration in sweat in patients with cystic fibrosis and a control group. Rothman and Sullivan4found 11 amino acids in water-wipings

“Combined” and free plasma alpha-amino nitrogen in normal pregnancy and toxemia

1.1. Total α-amino nitrogen of plasma is decreased in pregnancy, rising to normal levels 24 to 72 hours post partum.2.2. Serial determinations made on normal pregnant women and on patients with toxemia of pregnancy showed no apparent difference in plasma levels of α-amino nitrogen.3.3. “Combined” α-amino nitrogen of plasma is unaltered by pregnancy or toxemia of pregnancy.