PubMed Health⌕ Search

Biomedical subjects

A Randoux

Publications and source records attributed to A Randoux.

At least 55 records · Page 3Linked to original sources
PubMed1979

Fractionation and structure of several hydroxyproline-containing urinary peptides, with special reference to some 3-hydroxyproline-containing peptides.

After a preliminary separation of the hydroxyproline-containing peptides on Biogel P 2, the largest peptides are fractionated on phosphocellulose and the smallest ones on QAE-Sephadex. The fractions obtained from QAE-Sephadex are subfractionated on a column of Dowex 50-M-82. The total number of hydroxyproline-containing peptides from human urine is not less than 78. Sixteen di, tri and pentapeptides have been purified, their N-terminal amino acids and amino acid compositions determined and a structure is proposed. 3 of these peptides contain 3-hydroxyproline and one of these 3 peptides probably originates from basement membrane collagen.

Chromatography, Ion Exchange↗
PubMed1979

A method for the evaluation of 3-hydroxyproline in the urine.

After hydrolysis of the urine by 6 M HCl, 3-hydroxyproline is purified from many interfering substances by 2 steps of chromatography on Dowex 1 X8 resin equilibrated first in the acetate form and secondly in the OH- form. The amino acid is finally evaluated by chromatography on Dowex 50 M82 resin in a Beckman multichrom amino acid analyzer. In 23 normal adult subjects the mean level was 12.5 +/- 3.5 mumol/24 h. In 8 normal children the level was 6.0 +/- 5 mumol/24 h and in 8 teenagers 15.2 +/- 2.85 mumol/24 h. The ratio of 3-hydroxyproline to 4-hydroxyproline seems indicative of a semiological value of this evaluation in cases of basement membrane collagen deterioration.

Adolescent↗
PubMed1978

A new method of preparation and some properties of 3-hydroxyproline.

The hydrolyzate of Delonix Regia seed extract is fractionated sequentially on Dowex 50 X 8 resin and on QAE Sephadex A 25. Purification is completed by recrystallisation from ethyl alcohol. 3-hydroxyproline is destroyed by NO2H and by chloramine T, which prevents from using most of the colorimetric reactions in use for 4-hydroxyproline. For its characterization, 3-hydroxyproline may be clearly separated from 4-hydroxyproline by TLC chromatography and by high voltage paper electrophoresis.

Chromatography↗
PubMed1978

A fractionation of insoluble rat skin collagen.

After extraction of 1% of the total collagen of rat skin by 150 mM NaCl, a 1% SDS solution extracts 80% of the total collagen, while the residue is extracted by a mixture of beta mercapto-ethanol and SDS. These extractions, which respect the peptide linkages, cleave the allysyl cross-links. They provide an insight on the composition of some insoluble collagen molecules of the skin and on the importance of disulfide bridges in their architecture.

Animals↗
PubMed1978

[Microestimation of haemoglobins A2 and F by measurement of their peroxydase activity (author's transl)].

A microtechnique of evaluation for the haemoglobins A2 and F is presented, in which the final measurement is made more sensitive by evaluation of peroxidatic activity. Haemoglobin A2 is previously separated by chromatography on a very small column of DEAE cellulose and haemoglobin F is obtained through a microtechnique of alkaline precipitation. The sensitivity of this evaluation is increased by a factor of 20.25 microliter of hemolyzate are enough for a determination. Results obtained are in accordance with those given by the classical methods.

Fetal Hemoglobin↗
PubMed1978

A micromethod for the evaluation of hemoglobin A1c: technique and preliminary results.

A microtechnique of column chromatography on a Biorex 70 resin monitored by permanent recording of the effluent o.d., permits to obtain the percent of Hb A1C in an hemolyzate within 1.5 hr (in the place of 6 hrs in the usual techniques). This evaluation was carried out in 18 normal subjects and 32 patients suffering from diabetes mellitus and was repeated several times in 10 patients. The average level in the normal subjects was 5.01% (3.2 to 6.1%), in the equilibrated patients with a glycemia under 2 g/l: 6.44% (5.74 to 7.14%) and in the poorly equilibrated patients: 8.9% (5.5 to 15.3%). Hemoglobin A1C appears as a valuable index of sugar metabolic equilibrium.

Blood Glucose↗
PubMed1978

[Hemoglobin A1c: a new factor in the supervision of diabetes (author's transl)].

Hemoglobin A1c is one of the minor components of normal human hemoglobin. It differs from Hb A by the presence of one molecule of glucose fixed to the N-terminal extremity of every beta chain. It is synthesized from Hb A by a very slow and only slightly reversible mechanism which continuously occurs during the 120 days of the red cell life. Hb A1c represents nearly 5% of total hemoglobin of the normal subject. In patients suffering of diabetes mellitus, its level seems to reflect closely the degree of equilibrium of the disease for 4 to 5 weeks which preceeded the evaluation.

Chemical Phenomena↗
PubMed1976

Isolement et caractérisation de deux subunites constitutives des glycoproteines de structure du tissu sous cutané de lapin.

Structural glycoproteins have been extracted by 8 M ureau from the insoluble residue remaining after collagenase digestion of rabbit dermis and purified by Sepharose 4 B chromatography. After reduction and alkylation, Dowex 1 x 2 chromatography allowed separation of two structural glycoproteins (D1 and D2) in an homogenous state as shown by chromatographic and electrophoretic behaviour as well as N terminal amino acid determination. These two glycoproteins have a molecular weight of about 16 000. Their amino acid compositions (very similar), are characterized by a high level of dicarboxylic amino acids and the absence of hydroxyproline and hydroxylysine. The less acidic glycoprotein (D1) has glycine for N terminal amino acid and contains 10.4 percent of bound carbohydrates. The glycoprotein D2 contains 5.1 percent of bound carbohydrates and its N terminal amino acid is glutamic acid.

Amino Acid Sequence↗
PubMed1976

Effect of some purified plasma proteins on collagen biosynthesis in vitro.

The haptoglobin-hemoglobin complex activates the incorporation of 14C-proline into the collagen hydroxyproline of rat or human dermis slices incubated in vitro. The same complex decreases the incorporation of proline into the structural glycoproteins of the connective tissue. None of the other plasma proteins studied had any effect.

Animals↗
PubMed1975

A column chromatography fractionation of the hydroxyproline-containing urinary peptides with continuous automatic detection.

Dialyzable and non-dialyzable urinary hydroxyproline-containing peptides are chromatographed respectively on QAE-Sephadex and on phosphocellulose. They are detected and quantitated by continuous hydrolysis in 3.3 N NaOH followed by oxidation by chloramine T and colorimetry with p-dimethylamino-benzaldehyde. The patterns of dialyzable urinary hypropeptides do not show significant qualitative differences between normal subjects and patients suffering from Paget's bone disease or cancer metastases of bone. The patterns of non-dialyzable urinary hypropeptides, show more variability in the case of normal subjects and differ more largely in the case of Paget's disease of bone.

Autoanalysis↗