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Biomedical subjects

A Palou

Publications and source records attributed to A Palou.

At least 127 records · Page 7Linked to original sources
PubMed1983

A simplified method for the estimation of individual amino acid radioactivity in plasma samples.

A method is presented for the quantitative estimation of the individual amino acid radioactivity in biological samples. The material is deproteinized with cold acetone, and, after acetone evaporation, is passed through a column containing 1 g of Amberlite XAD-2, then eluted with 10% ethanol. The samples are derivatized with Sanger's reagent (alkaline 1-fluoro-2,4-dinitrobenzene) and passed again through the Amberlite XAD-2 column; the 10% ethanol eluate is now discarded and the DNP-amino acids eluted with acetone. Aliquots are used for TLC chromatography on Silicagel plates; the spots are identified, cut away and their radioactivity estimated. The actual recovery of radioactivity in the spots is about 86-92% of the initial radioactivity. No contamination with radioactive glucose, lactate, pyruvate or glycerol has been observed.

Amino Acids↗
PubMed1983

Body and organ size and composition during late foetal and postnatal development of rat.

Development induced deep anatomical changes and tissue composition alterations in the rat. To determine the extent of these changes, the organ weight and size of 19 and 21 day rat foetuses and of 1, 5, 10, 20 and 30 day old Wistar rat pups have been studied and compared with adults. Different tissues showed varying rates of cell and tissue growth as well as tissue cellularity during development. Tail length is not a good index of skeletal growth. Brain growth was much slower from late intrauterine life to adulthood than most other organs. Skin weight increased more than 3-fold between days 19 and 21 of intrauterine life. Striated muscle proportion to body weight remained practically constant throughout all postnatal life studied.

Age Factors↗
PubMed1983

Permeability of chicken egg vitelline membrane to glucose, carbohydrate gradients between albumen and yolk.

1. In the fertile chicken egg the albumen had higher carbohydrate concentration than the yolk with the highest concentration in the vicinity of the vitelline and shell membranes. 2. The mean half-life of glucose in the albumen was 18 hr during the first day of incubation. 3. Vitelline membrane was found to be freely permeable to glucose both from albumen to yolk and from yolk to albumen. 4. The amount of carbohydrate strongly linked to protein (glycoprotein) is similar in yolk and albumen. 5. There is an in vivo as well as in vitro fixation of free glucose by the albumen proteins. 6. Most carbohydrate of the fertile chicken egg was found to be loosely-linked to protein.

Animals↗
PubMed1983

Distribution of amino acids and amino-acid enzymes in whole kidney and renal cortex. Effect of 24-h starvation.

The levels of activity of amino-acid enzymes (alanine-, aspartate- and tyrosine transaminases, serine dehydratase, glutamate dehydrogenase, glutamine synthetase, arginase and adenylate deaminase) in the kidney cortex and whole kidney of control and 24-h starved adult rats have been determined from crude homogenates. The individual amino-acid content of the two kidney fractions indicated has also been studied. Serine dehydratase was found mainly in the cortex, whilst glutamine synthetase presence was mainly limited to the medulla. The distribution of adenylate deaminase and glutamate dehydrogenase is remarkably uniform along the kidney. Starvation induced decreases in arginase and adenylate deaminase activities as well as a decrease in cortical serine dehydratase. Analysis of the variance of the enzyme data showed no significant overall changes with respect to distribution and starvation. The same analysis applied to aminograms indicated only significant changes when the distribution was studied on starved samples as a whole, with changes mainly in the urea cycle and some essential amino acids. The results suggested a remarkable degree of uniformity in kidney composition both with respect to amino acid and enzyme distribution. This uniformity is not markedly affected by starvation despite the important rôle of kidney in the overall amino-acid economy of the Mammal.

AMP Deaminase↗
PubMed1983

Aspartate- and tyrosine transaminase activities in the organs of the rat during its breeding cycle.

The aspartate- and tyrosine transaminase activities of liver kidney, brain, hind leg striated muscle, skin, adipose tissue, small intestine and stomach of pregnant, lactating and post-lactating rats were determined. The ratios of activities between both enzymes were uniform in the different tissues studied, with minimal values for liver and adipose tissue. The patterns and activity ratios found during the breeding cycle of the rat agreed with tyrosine transaminase being an independent entity of aspartate transaminase in liver and adipose tissue, coexisting to some degree in most other tissues and being probably only an artifact (according to recent findings in the literature) in brain, muscle and intestine. The different patterns of change found during this period in most organs suggest different hormonal regulation and help support the possibility of an independent rôle for tyrosine transaminase in them.

Adipose Tissue↗
PubMed1983

Ontogeny of amino-acid metabolism-enzymes in peripheral tissues of developing rats.

The activities of alanine, aspartate and tyrosine transaminase, adenylate deaminase, glutamate dehydrogenase and glutamine synthetase have been measured in hind leg striated muscle, lumbar adipose tissue and lumbar skin of developing rats from late foetal to weaning stage. In a general way, despite minor differences and different physiological rôles, the three peripheral tissues studied showed a concordant enzyme activity pattern with the rôles found for these enzymes in the adult. Muscle had a more constant pattern throughout development, with wider changes in skin and widest in adipose tissue. The results found agree with a marked "synthetic" mode in the tissues studied throughout all development studied. The patterns observed agree with a strict amino-acid conservation scheme during foetal life and lactation that progressively changes with weaning towards a frank degrading mode.

AMP Deaminase↗
PubMed1983

Adenylate deaminase activity in the tissues of the rat during its breeding cycle.

The adenylate deaminase activity of muscle, liver, kidney, brain, intestine, stomach and adipose tissue have been measured during pregnancy, lactation and post-lactation of the rat. No significant changes have been found in muscle and kidney, with depressed values in the liver of pregnant rats--in agreement with the loss of metabolic rôle in nitrogen handling during this period--. Adipose tissue changes as well as those of skin actually followed anatomical changes in fat content of both tissues. Stomach and intestine patterns were significantly different, with a maximum for the bowel at mid-lactation.

AMP Deaminase↗
PubMed1982

Glutamine synthetase activity in rat tissues during pregnancy and lactation.

The glutamine synthetase activities of liver, striated muscle, kidney, brain, stomach, adipose tissue, small intestine and skin of rats during pregnancy, lactation and post-lactation were investigated as a probe of glutamine--and thus of ammonia--metabolism under a situation of altered amino acid utilization. There were significant increases in muscle activity in mid-pregnancy and in post-lactation. A transient relative decrease was observed in muscle enzyme on day 20 of lactation, compensated by an increase in small intestine activity. The results are discussed in light of the transporting role of nitrogen between peripheral and splanchnic tissues attributed to glutamine, as well as to the detoxyfying role of the enzyme for removal of nitrogen generated by the conceptus and by catabolism of amino acids under the increasing demand for energetic fuels in the peak of lactation.

Animals↗
PubMed1982

Amino-acid enzyme activities in liver and kidney of developing rats.

The amino-acid enzymes (aspartate-, alanine- and tyrosine transaminases, serine dehydratase, glutamate dehydrogenase, glutamine synthetase, adenylate deaminase and arginase) activities in the liver and kidney of developing rats (days 19 and 21 after conception and 1, 5, 10, 20 and 30 after birth) compared with adults were determined in crude homogenates. Most enzymes attained the adult levels early after birth or at weaning, showing a marked trend towards amino-acid nitrogen conservation during late foetal and specially during the neonatal period, increasing their activity during lactation. It is postulated that these changes are closely related to availability of low grade protein in diet as well as to maturation of amino-acid homeostasis maintenance for growth.

AMP Deaminase↗
PubMed1982

Changes induced in rat plasma composition by lactation.

Changes in rat plasma composition in post-partum period were studied from day 1 to post weaning recovery situation (day 40). Urea levels showed a significant increase at the peak of lactation, and glycerol levels showed a decrease towards late lactation. Changes in the plasma aminogram were more marked during the maximal intensity of lactation (days 10-20) and in postlactation. Low trypthophan levels were sustained throughout the lactation period. The combined amino acids showed significant increases on day 10 of lactation, and increases in non-essential and total amino acids in post-lactation (40 days). These results point towards increased amino-acid utilization during lactation.

3-Hydroxybutyric Acid↗
PubMed1981

A method for the estimation of amino acid radioactivity in biological samples.

A method for quantitative estimation of total radioactivity present in the free amino acid fraction of tissue samples has been described. Samples deproteinized with cold acetone were extracted, in acidic medium, with ethyl ether (peroxide free); after centrifugation, the aqueous phase was used for amino acid derivatization at 40 degrees C for 15 h with 1-fluoro-2,4-dinitrobenzene in bicarbonate-buffered medium. Aliquots of the derivatized samples were acidified and extracted twice again with ethyl ether. The combined organic phases were placed in glass scintillation vials, dried, and used for the determination of its radioactivity, corresponding to the radioactivity present in the free amino acid fraction of the sample. Deproteinized samples of rat blood plasma, as well as hen egg white and yolk were tested after addition of known quantities of 14C-labelled amino acids or glucose, for validation of the method. No glucose radioactivity was found in any of the extracted samples. All radioactivity added to the samples in the form of 14C-labelled alanine, glutamic acid, leucine and phenylalanine was quantitatively recovered in the derivatized fraction; only a fraction of arginine radioactivity was recovered.

Amino Acids↗