Biomedical subjects

R Coutelle

Publications and source records attributed to R Coutelle.

4 recordsLinked to original sources

PubMed1979

Evolutionary changes in protein composition -- evidence for an optimal strategy.

The information contained in the composition of different proteins of the same family is analyzed. It is found that within each family the gain in information per amino acid replacement is constant. This finding is interpreted to imply that evolutionary changes in proteins follow an "optimal" path in the sense that they maximize the number of potentially functional sequences that can be generated by T accepted point mutations from a given protein, subject to restrictions due to biological function.

Amino Acid Sequence↗

PubMed1979

[The effect of ethylnitrosourea in the activity of the NAD-linked glycero-3-phosphate dehydrogenase in the Vth nerve of developing rats and its relation to myelination and tumour induction (author's transl)].

The activity of NAD-linked L-alpha-glycero-3-phosphate dehydrogenase (E.C. 1.1.1.8.) in the Vth nerve from albino rats treated with a single subcutaneous injection of ethylnitrosourea in the first day of life and from controls was determined biochemically in 10 different age groups ranging from 7 to 70 days. The specific activities of the controls rise rapidly from the 7--35 days of life and remain there after almost at the same level. The activity of the ENU treated animals is significantly lower than that of the controls and reaches only at the age of 63 days the values of the 35 days old untreated animals. About 26% of the activity values of the treated animals are below the lower confidence limit of the controls.

Age Factors↗

PubMed1979

[Electronmicroscopic investigations of N. trigeminus of rats during the phase of tumour induction by ethylnitrosourea (author's transl)].

A single subcutaneous application of ENU to newborn rats causes after 2--4 days lethal and sublethal toxic lesions in some of the Schwann cells and their corresponding axons and myelin sheaths. The sublethally damaged Schwann cells show mainly alterations of myelin sheath formation. The ensuing regeneration produces between the 28.--35. day not only normal Schwann cells but also abnormal ones. These are characterized by atypical nuclei and a gradual loss of their functional relation to axons and are therefore regarded as Schwann cells in blastomatous transformation. The deviation from the normal of the NAD-linked L-alpha-glycerol-3-phosphate dehydrogenase caused by ENU correlates with the described morphological findings. Inspite of its partially unspecific character it may therefore be considered as an early indication of a beginning tumorous transformation.

Animals↗

PubMed1975

[Beta-glucuronidase activity and morphological alterations in the nervus trigeminus of the rat after application of the neurotropic carcinogen ethylnitrosourea (author's transl)].

Newborn rats were given subcutaneuously 85 mg ethylnitrosourea/kg body weight. The trigeminal nerves of the grown up and of infantile animals were histologically examined and their beta-glucuronidase activity biochemically determined. These activities were compared with those of untreated control animals of the same age. More than 50% of the enzyme values of the experimental animals were significantly higher than those of the controls. Most of the elevated activities were encountered in the central part of the nerve and consisted mainly of the pooled soluble and bound fraction of the enzyme. There is a positive correlation between the level of the enzymatic activity and the degree of morphological changes. An increased enzymatic activity was found in almost 100% of the tumor bearing nerves. Moreover such increased activities were found in a considerable number of histologically tumor free nerves. Ruling out other causes, for instance inflammation, it may be assumed that the increased activity of beta-glucuronidase in the trigeminal nerve of the rat after application of ethylnitrosourea is an expression of its carcinogenic effect and precedes the histologically visible alterations.

Animals↗