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Biomedical subjects

J Roche

Publications and source records attributed to J Roche.

At least 163 records · Page 9Linked to original sources
PubMed1978

The effects of trimethoprim and erythromycin on polysome metabolism in Escherichia coli.

Trimethoprim and erythromycin were shown to have different overall effects on in vivo polysome metabolism in Escherichia coli. In a rel A+-rel A pair of strains, trimethoprim treatment induces a reduction of polysome level to a variable extent, similarly to aminoacyl tRNA deprivation of cells, but persisting polysomes remain dynamic structures in a state of continual turnover. In contrast, erythromycin stabilizes polysome level to a high value in either kind of strain, but maintained polysomes appear as "frozen" structures unable to undergo ribosome translocation.

Erythromycin↗
PubMed1977

[Essential hypernatremia with hypovolemia caused by hypodipsia and partial diabetes insipidus].

The authors report the case of 13 year old girl presenting with chronic hypernatremia. This case should be considered as either neurogenic or essential hypernatremia. Partial diabetes insipidus and hypodipsia hypernatremia. Partial diabetes insipidus and hypodipsia are the cause of chronic hypovolemia and a new homeostasis with an exceptionally high level of sodium (isoosmotic point 154 mEq/l). No cause was found and in particular, the search for a cerebral disease was until now proved negative.

Adolescent↗
PubMed1977

Effect of hyper- and hypothyroidism on platelet monoamine oxidase activity and serotonin metabolism.

We evaluated platelet monoamine oxidase (MAO) activity in 13 hyperthyroid and 9 hypothyroid patients. The platelet MAO activity of these patients did not differ from that of age- and sex-matched euthyroid control subjects. Nineteen hyperthyroid and twelve hypothyroid subjects had serum serotonin concentrations similar to those of age- and sex-matched euthyroid control subjects. We also determined the urinary excretion of 5-hydroxy-indoleacetic acid (5-HlAA), serotonin, tryptamine, and tyramine in five hyperthyroid and four hypothyroid subjects. Two hyperthyroid patients had increased tyramine excretion; one of these patients also had increased tryptamine excretion. Three hypothyroid patients and one hyperthyroid patients had slightly decreased serotonin excretion. Both the hyper- and the hypothyroid subjects had normal urinary 5-HIAA excretion. There was no relationship between platelet MAO activity and monoamine excretion in the patients with thyroid dysfunction. We conclude that there is no systematic change in platelet MAO activity or serum serotonin concentration in patients with hyper- or hypothyroidism.

Adult↗
PubMed1977

[Biosynthesis of thyroglobulin in the endostyle of larva (ammocoetes) of a fresh water lamprey, Lampetra planeri B1].

The biosynthesis of thyroglobulin (Tg) in larva of a fresh-water lamprey, Lampetra planeri B1. has been established. This glycoprotein presents the same characters as in thyroid follicles of adult lampreys, as shown by its 18-19 S sedimentation coefficient and by the incorporation (in vivo and in vitro experiments of 4, 12, 72 h) of 125I, 3H-leucine and 3H-galactose. 3-8 S fractions and a 12 S monomer are the precursors of the 18-19 S protein. Total I % of Tg is very low (0.002 %) ; about 5 % of 125I are present in thyroid hormones (T3 and T4) in the 125I-labeled protein. The biosynthesis of 18-19 S Tg proceeds in larvs before the morphological differentiation of thyroid cells and follicles after metamorphosis. However, the biosynthesis of this protein is much slower in the endostyle of larvs, in which a primitive mechanism of storage is poorly efficient, compared to the accumulation of Tg in the colloid of the follicles of adults.

Animals↗
PubMed1977

[Carcinoid heart disease secondary to a tumor of the small intestine. Apropos of a case with associated tricuspid and pulmonary insufficiency].

The authors report a case of carcinoid heart disease secondary to a tumour of the small bowel with liver metastases. There were severe lesions of the endocardium on the right side of the heart, with gross pulmonary and tricuspid incompetence. The left side of the heart did not escape but the fibrous plaques were limited to the papillary muscle of the mitral valve, and had no effect upon the haemodynamics. The pathogenesis of the strange cardiac lesion may be partly explained in terms of the toxicity to the endothelium of bradykinin. In spite of the serious nature of the valvular damage is it right to consider surgical correction, bearing in mind the fact that the prognosis of carcinoid syndrome is still very poor despite treatment?

Aged↗
PubMed1976

Effect of oral contraceptives on platelet monoamine oxidase, monoamine excretion, and adrenocortical function.

Studies with animals indicate that there are cyclical changes in the monoamine oxidase (MAO) activity of brain and uterus, and that these changes may be due to changes in estrogen and progesterone levels. To determine if oral contraceptives (OC) alter the tissue MAO activity of healthy women, we measured platelet MAO activity in 7 control women and in 7 women who were receiving combination estrogen-progesterone OC. The platelet MAO of the control women and the women receiving OC did not differ with the use of tryptamine and serotonin as MAO substrates. The two groups did not differ with respect to the following: serum serotonin, plasma tryptophan, plasma tyrosine, and the urinary excretion of tryptamine, tyramine, serotonin, 5-hydroxyindoleacetic acid, creatinine, 17-hydroxycorticosteroids, 17-ketosteroids, and urinary free cortisol. The subjects receiving OC had higher plasma cortisol concentrations than the controls. Two women in the seventh month of uncomplicated pregnancy, who underwent these studies, had higher plasma cortisol and urinary 17-ketosteroid excretion than control subjects. In the remaining tests the results of pregnant subjects did not differ from those of control subjects. We conclude that tissue MAO activity is not altered by OC or pregnancy.

Adrenal Cortex↗
PubMed1976

Collecting and processing records from the ultracentrifuge in "real-time" using an on-line computer.

An analytical system consisting of an analytical cantrifuge coupled 'on-line' to a computer was assembled and tested. Collection of records from up to 9 solutions was achieved through programmes which sum readings to reduce noise as well as controlling the positioning of the scanner. With this system it was found that the limit on accuracy for molecular weights at concentrations less than 0.01 g cm-3 was +/- 3% estimated from sedimentation equilibrium experiments. The same system was used to collect records for similar concentrations from velocity experiments by employing a scanning schlieren. In this case the accuracy in estimating sedimentation coefficients was similar to those found when measuring photographs. Since the collection yields detailed information about the shape of the sedimenting boundary, the centroids of the boundary were routinely computed by second moment analysis rather than relying on the position of the maximum of the schlieren peak. In the same analysis estimates of diffusion coefficients were made routinely by calculating corrected height/area ratios for each scan. These calculations were made during the real-time of the experiment, so making available molecular parameters rather than records which must be evaluated some time after stopping the experiment.

Computers, Hybrid↗
PubMed1976

[Biosynthesis of thyroglobulin in an adult lamprey, Lampetra planeri (Bloch)].

Thyroglobuline (Tg) biosynthesis has been studied in an adult fresh water lamprey Lampetra planeri (Bloch), by injection in coelomic cavity or by in vitro incorporation in follicles of branchial region of various radioactive labels: 125I-, 3H-leucine, 3H-mannose, 3H-galactose, N-acetyl mannosamine and 3H-N-acetylglucosamine. Labelling by all theses substances, present in Tg of mammals, proceeds efficiently in two hours. It has been demonstrated that the cyclostome studied synthetizes a 18 S iodinated glycoprotein analogous to Tg of higher vertebrates by its molecular size. It contains all the same hexose and N-acetyl derivatives of these in its sugar moiety and the same iodinated aminoacids. Purified 18 S Tg of the lamprey has been prepared; it is very poor in iodine (127I) and has a very low T3 and T4 content.

Acetylglucosamine↗