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Biomedical subjects

M Rolland

Publications and source records attributed to M Rolland.

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

Radioiodination of tyrosine residue(s) of ox testis and of wheat germ calmodulins.

Radioiodination of the two tyrosine residues (Tyr-99 and Tyr-138) of ox testis calmodulin was performed using several methods, and studied through the specific activity, and the [125I]iodoamino acid analysis of the radiolabeled calmodulins. Hydrolysis by thrombin of 125I-calmodulin labeled by the lactoperoxidase method and subsequent isolation of peptides TM1 and TM2 by gel electrophoresis showed preferential labeling by 125I of Tyr-99 (TM1) over Tyr-138 (TM2). Analysis of [125I]iodoamino acids of radiolabeled TM1, TM2 and calmodulin demonstrated that [125I]monoiodotyrosine was predominant, the remainder being [125I]diiodotyrosine. Radioiodination of wheat germ calmodulin, which contains a single tyrosine residue (Tyr-139), showed that only TM2 was labeled by 125I on the Tyr-139 residue and also on the His-108 residue (radiolabeled monoiodotyrosine, diiodotyrosine and monoiodohistidine being present).

Animals↗
PubMed1985

In vitro synthesis of thyroxine in a low molecular weight polypeptide fragment from human thyroglobulin.

A peptide fragment of Mr 16 K was purified from the cyanogen bromide digest of human thyroglobulin either normally iodinated in vivo (0.21 % I) or highly iodinated in vitro (1.40 % I). This peptide segment represents in the native molecule a zone in which tyrosine residues are not or poorly accessible to iodination and consequently do not produce thyroxine. In contrast, after isolation from thyroglobulin and iodination in vitro, the peptide is capable of synthesizing thyroxine with a high efficiency. It is concluded that the peptide described which probably represents a potential hormone forming site in the whole thyroglobulin molecule should constitute a valuable model to study the mechanism of thyroxine formation in vitro.

Amino Acids↗
PubMed1984

Precursor-product relationship between the 26-kDa and 18-kDa fragments formed by iodination of human thyroglobulin.

At moderate iodination levels (20 iodine at atoms/molecule), human thyroglobulin (hTgb) produces after reduction a thyroxinyl-peptide of 26 kDa which represents the N-terminal part of the protein. At higher iodination levels, the 26-kDa peptide is accompanied by another T4-containing peptide of 18 kDa. A precursor-product relationship between the 26- and 18-kDa fragments was demonstrated by the study of the tryptic fragments of both hormonopeptides. In addition, comparison with the protein sequence deduced from the nucleotide sequence of the 5'-end of hTgb mRNA demonstrated that the N-terminal region of Htgb from which are issued the 26-kDa peptide and its 18-kDa derivative is especially sensitive to proteolysis. This character is possibly related with a facilitated release of thyroid hormones in vivo.

Amino Acid Sequence↗
PubMed1984

[Relation between the iodination of human thyroglobulin and the cleavage of the hormone peptide 26K N-terminal].

At moderate iodination levels (about 20 iodine atoms/mol) human thyroglobulin yields after reduction and alkylation a hormone (T4)-containing N-terminal peptide of 26K. Further iodination of the thyroglobulin in vitro results in the cleavage of this part of the molecule into smaller peptides of 22K and 18K. A precursor-product relationship between the 26K peptide segment and the latter was established by showing an identical N-terminal T4-containing sequence in the 3 peptides. Cleavage of peptide bonds in the 26K segment to give the smaller fragments could possibly be related to the formation of another hormone residue.

Amino Acid Sequence↗
PubMed1984

[Comparison of quantity of thyroxine in thyroglobulin and the peptide hormones derived from chromatography and immunoenzyme assay].

An evaluation of the thyroxine content in thyroglobulin and different derived thyroxine-containing peptides by enzyme immunoassay is presented. Results correlate very well with those obtained by ion-exchange chromatography which served as a reference method: r = 0.997, p less than 10(-6). Enzyme immunoassay is more rapid and sensitive than ion-exchange chromatography and then suitable for routine use. Furthermore, this paper shows, for the first time, that enzyme immunoassay can be used to perform direct thyroxine estimation in small peptide (Mr less than 2,500) without previous total enzymatic hydrolysis.

Animals↗
PubMed1984

[Trisomy 12(pter----q12) and monosomy 21(pter----q21). A propos of a case].

The authors report an observation of a child with both trisomy 12(pter----q12) and monosomy 21(pter----q21). It is thus possible to detect the clinical signs which can be attributed to trisomy 12p and to monosomy 21ql respectively. The authors point out the originality of the maternal translocation which differs from the translocations affecting these two chromosomes previously described in the literature. Finally, the rarity of the type of adjacent-2 segregation is shown, and discussed according to the literature already published.

Chromosome Aberrations↗
PubMed1983

Amino acid sequence around a hormonogenic tyrosine residue in the N-terminal region of human thyroglobulin after in vivo and in vitro iodination.

Reduced and S-alkylated human thyroglobulin (hTgb), normally iodinated, was previously shown by SDS/PAGE to contain a small peptide (Mr 26 000) rich in thyroxine. This peptide was not found when very poorly iodinated hTgb was treated under the same conditions but was present after iodination in vitro. Peptide 26 K was purified from in vivo and in vitro iodinated hTgb. The study of these peptides shows that: 1/ at the iodination levels studied (0.18 and 0.25% iodine) one of the preferential hormonogenic sites is the same in hTgb iodinated both in vivo and in vitro; 2/ the amino acid sequence around the thyroxine residue: Asn-Ile-Phe-Glu-T4-Gln-Val is identical with the previously described hormonogenic site of bovine thyroglobulin. Most probably the hormone-containing peptide 26 K is the N-terminal peptide of the hTgb chain.

Amino Acid Sequence↗
PubMed1983

In vitro and in vivo iodination of human thyroglobulin in relation to hormone release.

Reduced and S-alkylated thyroglobulin (Tgb) from different species were shown by SDS-PAGE to contain small peptides (from 45-9 kDa) rich in thyroxine. Several hypotheses were proposed to explain their origin. The polypeptide composition of iodine-poor (Tgb A) and normally iodinated (Tgb B) human Tgb prepared by two different procedures (one minimizing and the other favoring post-mortem proteolysis) was compared in the native state and after in vitro iodination. Results show that one of the hormonogenic sites of human Tgb is part of a domain of the molecule most susceptible to proteolysis, especially when it is very iodinated.

Electrophoresis, Polyacrylamide Gel↗
PubMed1983

Amino acid sequence of the unique 3,5,3'-triiodothyronine-containing sequence from porcine thyroglobulin.

A unique T3-containing peptide was isolated by chemical and enzyme treatments from pTgb of different iodine contents and microsequenced: Leu-Ala-Ser-Lys-Ser-T3. This site can also form T4 to a small extent. It contains all the T3 of the protein and presents a special susceptibility to proteolysis thus suggesting a likely mechanism to explain that the thyroid secretes T3 preferentially to T4 in vivo.

Amino Acid Sequence↗
PubMed1983

[Antenatal treatment of fetal urinary tract malformations. Apropos of the treatment of a case of posterior urethral valves].

Palliative in utero treatments of certain malformations of the fetal urinary tract are now possible. The most important of these is urethral obstruction by valves. A case of in utero treatment of such a disease is reported, with a six month follow-up of the infant. In utero diversion of urine was performed by means of a catheter placed in the bladder using a technique derived from intra-uterine transfusions. The purpose is to permit drainage of urine from the kidneys into the liquor to prevent permanent damage to the kidneys because of back pressure. The technical problems included deciding the correct size of catheter and the technique of localising the bladder and inserting the catheter under ultrasound control. The ethical problems are raised partly because there is no central ethical committee to make decisions and partly because of the need to evaluate and to inform the patients of the various risks. The patients take the risk on behalf of their children and the mother takes a small risk for her own health.

Abnormalities, Multiple↗
PubMed1983

[Secondary 18q2 due to a paternal double translocation].

Trisomy 18q2 in a boy associated with a reciprocal translocation due to a paternal balanced complex rearrangement interesting chromosome 9, 10 and 18 is reported. Using this observation phenotypical data of the "typical" clinical description are discussed and some particular signs are pointed out. About the occurrence of the complex chromosomal rearrangement different hypothesis are considered.

Chromosomes, Human, 16-18↗
PubMed1982

[Serum profile of inflammatory reaction proteins in arteriopathies of the lower limbs, stage II].

The serum content of proteins involved in the inflammatory process was investigated, partly through kinetic immunodiffusion, in 85 men subdivided as follows: 45 men (aged 57 +/- 5 years) with intermittent claudication due to arteriosclerosis obliterans; 20 controls matched for sex and age; 20 sex-matched controls whose mean age was 25 +/- 3 years. Patients with obliterating arteriosclerosis had signs of both subacute and chronic inflammation. Compared to controls, they had a higher sedimentation rate, a lower percentage of serum albumine, higher percentages and absolute serum contents os alpha 1, alpha 2 and beta globulins, and higher serum concentrations of fibrin, orosomucoid, C3 complement fraction and IgA. In addition, the modifications of these proteins were closely correlated. These results are consistent with previous reports concerning patients with coronary heart disease. They point out the relationship between inflammation and atherosclerosis.

Adult↗