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Biomedical subjects

A Pons

Publications and source records attributed to A Pons.

At least 73 records · Page 4Linked to original sources
PubMed1986

Effect of starvation and protein-feeding on blood amino acid compartmentation of domestic fowl hatchlings.

The amino acid concentrations in plasma and blood cells of 5-day old domestic fowl hatchlings that received either standard feeding, protein-feeding or were starved have been determined. The effects of 5-day starvation or protein feeding did not alter significantly the combined amino acid concentration of blood plasma, but decreased blood cell levels. The patterns of individual amino acid changes observed in starvation or protein-feeding were similar in both groups when compared with those of controls. However, starvation-induced effects were actually more marked than those observed in protein-fed animals. The patterns of change with starvation of individual amino acids in the hatchling blood compartments were very different from those observed in mammals subjected to short or medium-term starvation. The mechanisms controlling circulating amino acid concentrations act in both situations studied to maintain the plasma amino acid concentrations despite marked changes in the availability of 2-amino nitrogen energy to the animal; changes in blood amino acid compartmentation buffering plasma amino acid availability.

Amino Acids↗
PubMed1986

Tissue glycogen and lactate handling by the developing domestic fowl.

The levels of glycogen and lactate in liver, intestine, yolk sac membrane and leg and breast muscle of domestic fowl from day 10 of "in ovo" development to day 5 after hatching compared with adults have been measured and compared with the circulating concentrations in blood of glucose and lactate. Glycogen stores in most tissues increased before hatching to attain a minimum around the eclosion and then increased to adult values in muscle and liver. Lactate maintained its plasma concentrations with higher effectiveness than plasma glucose, which increased steadily up to adult levels from hatching. The study of tissue vs plasma lactate concentration ratios suggests a general activation of lactate metabolism from hatching, coinciding with the ingestion of carbohydrate-based food. Both muscles studied, as well as intestine, seem to be net lactate producers; blood cells can speculatively be considered as lactate users and liver maintains its concentration of lactate very close to that plasma, suggesting a fast utilization of this material as well as liver being the main site for control of circulating lactate.

Aging↗
PubMed1986

Tissue glycogen and lactate handling by the developing domestic fowl.

The levels of glycogen and lactate in liver, intestine, yolk sac membrane and leg and breast muscle of domestic fowl from day 10 of "in ovo" development to day 5 after hatching compared with adults have been measured and compared with the circulating concentrations in blood of glucose and lactate. Glycogen stores in most tissues increased before hatching to attain a minimum around the eclosion and then increased to adult values in muscle and liver. Lactate maintained its plasma concentrations with higher effectiveness than plasma glucose, which increased steadily up to adult levels from hatching. The study of tissue vs plasma lactate concentration ratios suggests a general activation of lactate metabolism from hatching, coinciding with the ingestion of carbohydrate-based food. Both muscles studied, as well as intestine, seem to be net lactate producers; blood cells can speculatively be considered as lactate users and liver maintains its concentration of lactate very close to that of plasma, suggesting a fast utilization of this material as well as liver being the main site for control of circulating lactate.

Aging↗
PubMed1986

Effect of starvation and a protein diet on the amino acid metabolism enzyme activities of the organs of domestic fowl hatchlings.

The activities of alanine and aspartate transaminases, adenylate deaminase, glutamine synthetase and glutamate and xanthine dehydrogenases have been measured in liver, yolk sac membrane, intestine and breast and leg muscle of domestic fowl hatchlings receiving for 3 or 5 days either a standard diet or hard boiled eggwhite as well as in 3 or 5 days starved animals. The patterns of activation of amino acid metabolism enzymes were fully comparable in protein-fed and starved groups with respect to fed controls; the differences with respect to the latter became more marked in 5- than in 3-days old chicks. In 5-days old chicks intestine alanine transaminase activity increased in parallel to that of liver in protein-fed animals but not in those starved, in agreement with an enhanced alanine transfer between both organs under this situation. Both, starvation and protein-feeding, induced a general decrease in the amino acid metabolizing ability of muscle. Glutamine (but not alanine) synthetizing capabilities were enhanced.

AMP Deaminase↗
PubMed1986

Sex differences in blood amino acid concentration and cell/plasma distribution in the domestic fowl.

The amino acid concentration of and distribution between the cell and plasma of the blood of male and non-laying female domestic fowl have been determined. No significant differences in plasma amino acid content were observed between the sexes, except for higher serine and lower asparagine concentrations in the female. Hens had higher intracellular concentrations of aspartate, hydroxyproline, arginine, lysine and cystine and lower concentrations of cysteic acid and taurine. The proportion of amino acids carried in the blood cells of fowls was about 80%, a value that is much higher than that found in mammals. The mean ratio of combined total amino acid concentrations between plasma and cells was about 8-fold, again much higher than the corresponding figures in mammals.

Amino Acids↗
PubMed1986

Liver- and muscle amino-acid concentrations during the development of domestic fowl.

The concentrations of free amino acids in liver, leg muscle and wing muscle of developing domestic fowl chicks were measured and compared with those of adults. Leg and breast muscles showed a remarkably parallel pattern of change in free-amino-acid concentrations during development up to day 5 after hatching, in agreement with their lack of differentiation up to day 5. Liver free-amino-acid concentration pattern with the development were very similar to those of the muscles, in significant difference with Mammals. Adult free tissue amino acids were lower than those of developing chicks. Most changes in amino-acid concentration in chick tissues were observed around hatching, and have been tentatively attributed to changes in diet. Combined amino acids changed very little during the period studied in muscles and liver. Taurine constituted a very big share of total amino acids.

Age Factors↗
PubMed1986

Amino-acid metabolism enzyme activities in the liver, intestine and yolk sac membrane of developing domestic fowl.

To contribute to our understanding of nitrogen metabolism in the developing chick we have studied in liver, intestine and yolk sac membrane the ontogeny of both aspartate- and alanine transaminases, glutamate dehydrogenase, adenylate deaminase, glutamine synthetase and xanthine dehydrogenase activities. Liver enzyme activities were much higher than those of the same enzymes in intestine and yolk sac membrane, the latter having the lowest activities. In the liver, both alanine transaminase and glutamate dehydrogenase increased their activity just before hatching, xanthine dehydrogenase and glutamine synthetase develop their highest activity just after hatching, while aspartate transaminase and adenylate deaminase attained the highest levels just with adulthood. From the pattern of enzyme activity in yolk sac membrane and intestine it can be inferred that after hatching, the amino-acid metabolism in these tissues is considerably enhanced, with higher production of ammonia from amino acids, as indicated by the rise in adenylate deaminase, as well as increased potentiality in production of both alanine and glutamine. It can be concluded that hatching coincides with a deep change of pace in amino-acid metabolism in the organs studied fully comparable with that observed in Mammals at the end of lactation, with the difference that the adaptation to the new diet in the case of the chick is much more sudden than weaning is for the rat.

AMP Deaminase↗
PubMed1985

Patterns of amino acid enzyme in domestic fowl breast and leg muscle during development.

Activities of alanine and aspartate transaminases, glutamine synthetase, adenylate deaminase, glutamate and xanthine dehydrogenases and lactate dehydrogenase were measured in leg and breast muscles of developing chicks from day 10 in ovo to day 5 of free life, and compared with measurements for adult hens. Xanthine dehydrogenase activity was low in both muscles with adult levels attained on day 15 in ovo. Glutamine synthetase for chicks was maintained higher during development than for adults in both muscles. Minor differences were observed between both muscles in all enzymes tested up to day 18. With low embryonic values and important rises before hatching, the differences were initiated in the posthatching period. Important differences were observed between adult levels of activity. Leg muscle revealed higher enzyme values except for lactate dehydrogenase and indistinguishable levels for adenylate deaminase and xanthine dehydrogenase in both muscles. Alanine, instead of glutamine, is postulated as the main nitrogen transport between muscle and liver in the domestic fowl.

AMP Deaminase↗
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↗
PubMed1982

[Value of basophil studies in the diagnosis of drug allergies].

Mastocytes and basophils are the two cell populations involved in the reactions seen during drug allergies. The testing of basophils is the only and simplest way of studying sensitization in the IgE system by a drug antigen, especially when the skin tests cannot be carried out. This study is carried out in two steps: straight after the drug-induced accident, where a basophil count will give an idea of its allergic origin; and some time after the accident, where the human basophil degranulation test (H.B.D.T.) helps to identify in over 50 p. 100 of cases the responsible drug. The basophil count and H.B.D.T. techniques are then described. The authors present their own results. In a study by H.B.D.T. of 908 patients with a drug allergy, 53.2 p. 100 had positive test; 57.6 p. 100 of 33 cases who presented an anaesthetic accident had a positive H.B.D.T.

Anesthetics↗
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↗
PubMed1981

A method for the simultaneous determination of total carbohydrate and glycerol in biological samples with the anthrone reagent.

A method for quantitative estimation of glycerol and total carbohydrate in biological samples is described. The samples, deproteinized with cold acetone or trichloroacetic acid, were treated in the cold with 10 vols. of 0.75% (w/w) anthrone in 84% (w/w) sulphuric acid, and then heated 10 min at 100 degrees C. Absorbance at 590 nm was used for evaluation of total carbohydrate content in the sample. The absorbance at 510 nm was used for the combined carbohydrate and glycerol estimation. This latter observation leads to the determination of the glycerol content of the sample because the carbohydrate interference is known from the data obtained at 590 nm. Uses of this method to determine glycerol and carbohydrate content in lipids of chicken egg-yolk samples are presented.

Animals↗
PubMed1981

[Cerebral irradiation as adjuvant therapy in the treatment of small cell carcinoma of the lung (author's transl)].

The authors present the results of a non randomized study of 33 patients suffering from small cell carcinoma of the lung. After a similar course of monthly chemo-therapy (Endoxan Oncovin, Natulan, CCNU) and mediastinal irradiation in a dose of 30 grays in 10 fractions over two weeks, 14 patients were given adjuvant cerebral irradiation, the 19 others made up the control group (30 grays to the brain overall in 10 fractions over two weeks). With a minimum follow up for 12 months, 42% of the control group had evidence of cerebral secondaries, as opposed to none in the irradiated group with any neurological signs whatsoever. The indisputable efficacy of adjuvant cerebral irradiation contrasts with the absence of any significant improvement in survival time : 2 patients are alive and in complete remission, 1 in each group, while the mean survival was 12.3 and 11.7 months respectively. This is explained by the continued occurrence of extra-cerebral metastatic deposits such as the liver or mediastinum where the efficacy of systemic therapy remains uncertain. The therapeutic approach is currently orientated in two directions : - to raise the dose delivered to the mediastinum even if it appears radiologically normal. - to continue research into new chemo-therapeutic combinations more specifically active at the hepatic level.

Antineoplastic Agents↗
PubMed1977

[Evaluation of the results of radiotherapy in 14 cases of malignant thymoma. Therapeutic prospects].

The authors present a critical review of 14 cases of malignant thymomas. They point out that the development of the tumours is similar to Hodgkin disease's (13 relapses in contiguous areas), that surgery is never sufficient for cure and that radiosensitivity is high (in 8 patients radiotherapy alone results in a total and early regression of the tumour). Therefore the authors propose a complementary post-operative treatment by limited irradiation and MOPP type polychemotherapy. This temporary choice of treatment can be reevaluated after further case studies. To facilitate this they wish that a cooperative project could gather the rare and dispersed observations of different centers.

Adult↗