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Biomedical subjects

D Blanchard

Publications and source records attributed to D Blanchard.

At least 199 records · Page 11Linked to original sources
PubMed1985

Identification of a novel ganglioside on erythrocytes with blood group Cad specificity.

The blood group Cad antigen is a carbohydrate structure well characterized on the sialoglycoproteins of the red cell membrane from some rare individuals (Blanchard, D., Cartron, J. P., Fournet, B., Montreuil, J., Van Halbeck, H., and Vliegenthart, J.F.G. (1983) J. Biol. Chem. 258, 7691-7695). However, protease treatment of whole cells did not destroy their antigenic activity which indicated that glycolipid might also be involved in the antigenic reaction. A crude ganglioside fraction was prepared from Cad cells and found to inhibit the hemagglutination reaction, whereas neutral glycolipids were inactive. Further analysis of the ganglioside extract from Cad erythrocytes by thin layer chromatography revealed an unusual profile characterized by a lower content of sialosylparagloboside and the presence of a novel ganglioside of slower mobility. Immunochemical studies demonstrate that this ganglioside binds Helix pomatia lectin and inhibits human anti-Sda antibody. In addition, a ganglioside with identical chromatographic mobility can be obtained by the enzymatic transfer of GalNAc from UDP-GalNAc to sialosylparagloboside using a microsomal preparation from human kidney. These results together with cell surface labeling experiments suggest that the major ganglioside of Cad erythrocytes might be derived from sialosylparagloboside by substitution with an additional N-acetylgalactosamine residue.

Animals↗
PubMed1985

Structure determination of oligosaccharides isolated from Cad erythrocyte membranes by permethylation analysis and 500-MHz 1H-NMR spectroscopy.

Alkaline borohydride reductive cleavage (beta-elimination) of glycophorin A isolated from one individual of the rare blood group Cad, resulted in the release of six acidic oligosaccharide-alditols which were separated by high-performance liquid chromatography (HPLC) on an alkyl amine silicagel column. The structure of four of them has been determined by the application of methanolysis, methylation analysis and 1H-NMR spectroscopy at 500 MHz. The structures and relative amounts were as follows: oligosaccharide 1: NeuAc(alpha 2-3)Gal(beta 1-3)GalNAc-ol (3.5%); oligosaccharide 3: GalNAc(beta 1-4)[NeuAc(alpha 2-3)]Gal(beta 1-3)GalNAc-ol (10.5%); oligosaccharide 5: NeuAc(alpha 2-3)Gal(beta 1-3)[NeuAc(alpha 2-6)]GalNAc-ol (10.4%); oligosaccharide 6: GalNAc(beta 1-4)[NeuAc(alpha 2-3)]Gal(beta 1-3)[NeuAc(alpha 2-6)]GalNAc-ol (71.2%). The two other oligosaccharides (2 and 4) were obtained in very low amount. The major pentasaccharide (oligosaccharide 6) carries the blood group Cad determinant and is a potent inhibitor of human anti-Sda antibody.

Blood Group Antigens↗
PubMed1984

Interaction of Vicia graminea anti-N lectin with cell surface glycoproteins from erythrocytes with rare blood group antigens.

The erythrocyte receptors for Vicia graminea (Vg) anti-N lectin have been investigated after 125I-labelling of the purified lectin and binding to membrane components separated by dodecyl sulphate polyacrylamide gel electrophoresis. GP alpha (synonym glycophorin A or MN glycoprotein) and GP delta (synonym glycophorin B or Ss glycoprotein) are the main Vg receptors of native human blood group NN and MN erythrocytes whereas Vg lectin only binds to GP delta from MM red cells. The glycoprotein of 28 kDa present in Mi III erythrocytes (a presumed variant of GP delta) carries Vg receptors. Both binding studies and agglutination experiments with this lectin suggest that the delta Mi III gene might produce more glycoprotein molecules than the normal delta gene. Binding of Vg lectin to hybrid glycoproteins [from Mi V, St(a+) and Dantu (+) donors] produced by unequal crossing-over between alpha and delta genes, may occur if the molecules exhibit N activity. The lectin does not bind to sialic acid- and galactose-deficient glycoproteins from Tn erythrocytes and no binding could be detected in the region of GP delta of erythrocytes from S-s-U-individuals. Addition of N-acetylgalactosamine residues to the alkali-labile oligosaccharides attached to GP alpha and GP delta, as found in Cad erythrocytes, decrease the binding capacity for Vg lectin. Finally the absence of Vg lectin binding sites on native GP alpha molecule from MgMg and McM erythrocytes, which carry well defined variants of this glycoprotein, supports the view that the binding site of the lectin on native glycoproteins is located at the N-terminal end of glycoprotein (GP alpha and GP delta) with N specificity (N-terminus = Leu).

Antigens, Surface↗
PubMed1984

A monoclonal antibody directed against the homologous N-terminal domain of glycophorin A and B.

A monoclonal antibody (iB5, IgG1 kappa) reacting with human red cells was produced after immunization of BALB/C mice with cord red cells, followed by fusion of the spleen cells with the murine myeloma cell line Ag 8-653. The monoclonal antibody agglutinated blood group N+ much better than M + N-red cells but did not recognize erythrocytes from rare individuals typed as M + N-S-s-U- and those from an En(a-) individual (M.E.P.). However, S-s-U- donors typed as M + N + or M-N+ and En(a-) red cells from donor G.W. were agglutinated. The erythrocyte receptors for iB5 are completely destroyed by papain treatment and significantly decreased by neuraminidase. Interestingly also, the iB5 antibody failed to agglutinate trypsin-treated N+M-S-s-U- erythrocytes. Other investigations have shown that the monoclonal antibody precipitated glycophorin A and B from N+ red cells and only glycophorin B from M+N-erythrocytes. The reactivity of iB5 was further explored by immunostaining following the electrophoretic transfer to nitrocellulose sheets of membrane proteins from common (M and N) and rare erythrocytes [En(a-),S-s-U-, MgMg, McM, St(a+), Mi.V, Mi.III, Tn] separated by SDS-polyacrylamide gel electrophoresis. These studies have clearly demonstrated that the monoclonal iB5 antibody is directed against the homologous N-terminal domain of glycophorin A and B, a specificity which explains the serological reactivity of iB5 against common and rare erythrocytes.

Animals↗
PubMed1984

[Magnesium deficiencies in cardiovascular diseases].

Plasma (pl), red blood cell (ery) and urinary magnesium (Mg) concentrations were measured by spectrophotometry in over 300 patients at the Cardiology Department of Broussais Hospital. Other biological parameters, including pl and ery potassium, calcium and phosphate concentrations were measured simultaneously. In a control group (54 subjects) the mean pl Mg was 0,851 mmol/l in men and 0,819 mmol/l in women; mean ery Mg was 2,12 mmol/l and 2,09 mmol/l respectively. Magnesium depletion was observed in several pathological cardiovascular conditions: -- mitral valve prolapse: the Mg levels were significantly lower in women (19 cases) (pl Mg 0,740 mmol/l; ery Mg 1,83 mmol/l: p less than 0,001); the deficit was less pronounced in men: pl Mg 0,829 mmol/l, p less than 0,01, and ery Mg 2,01 mmol/l (NS); -- recurrent junctional tachycardia (21 cases): the Mg levels were significantly lower than normal: pl Mg = 0,796 mmol/l in men and 0,763 mmol/l in women; ery Mg = 1,93 and 1,88 mmol/l, respectively; -- coronary insufficiency (86 cases): pl Mg = 0,821 mmol/l in men and 0,768 mmol/l in women (p less than 0,001). In a subgroup with coronary spasm (22 cases), the mean ery Mg was decreased (2,01 mmol/l, p less than 0,05); -- unstable or labile hypertension (24 cases): the decrease was significant, especially in women (pl Mg = 0,796 mmol/l, ery Mg = 1,88 mmol/l). These magnesium deficits were sometimes associated with a low pl Ca, and often associated with a low ery K although pl K was usually raised. In some privileged cases of cardiac arrhythmia and coronary spasm, intravenous Mg repletion was beneficial but did not affect plasma concentrations. The role of magnesium depletion in cardiovascular disease remains obscure and requires further study.

Adolescent↗
PubMed1983

Miltenberger Class I and II erythrocytes carry a variant of glycophorin A.

The membranes from Miltenberger Class I (Mi I) and II (Mi II) erythrocytes, two rare variants at the blood group MNSs locus, exhibited an abnormal glycoprotein of 32 kDa apparent molecular mass sharply stained by the periodic acid/Schiff procedure and a decreased content of glycoprotein alpha (synonym glycophorin A, glycoprotein MN) as seen on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Purified 125I-labelled Vicia graminea lectin binds to the unusual 32 kDa glycoprotein separated from Mi I and Mi II erythrocyte membrane of blood group NN or MN, but no significant labelling of this band was observed with Mi samples typed MM. On the basis of such lectin-labelling experiments we have described two heterozygous MN, Mi I individuals that carry one copy of an M gene producing a normal alpha-glycoprotein with M-specificity and one copy of a MiI gene producing a 32 kDa glycoprotein with N-specificity. Further investigations have shown that the 32 kDa glycoprotein was immunoprecipitated by two mouse monoclonal antibodies (R18 and R10) reacting specifically with the external domain of glycoprotein alpha. These results demonstrate that Mi I and Mi II erythrocytes carry an unusual variant of glycoprotein alpha.

Antibodies, Monoclonal↗
PubMed1983

Primary structure of the oligosaccharide determinant of blood group Cad specificity.

Glycophorin A and B from Cad erythrocyte membranes are the carriers of the blood group Cad determinants. They are characterized by a significant increase in molecular mass, as compared to the corresponding glycophorins from control erythrocytes (Cartron, J.-P., and Blanchard, D. (1982) Biochem. J. 207, 497-504). Lipid-free glycophorin A, purified from Cad red cells, showed an increased GalNAc content in comparison to blood group B, Cad-negative, control cells. Alkaline-borohydride treatment of this Cad glycophorin A released as a predominant species a pentasaccharide; its structure was determined, by methylation analysis and by 500-MHz 1H-NMR studies, to be: (formula; see text) This novel oligosaccharide inhibited strongly the hemagglutination of Cad erythrocytes by the Dolichos biflorus lectin. It shares with the blood group Sda determinant a terminal GalNAc beta (1 leads to 4)Gal beta (1 leads to .) sequence.

Blood Group Antigens↗
PubMed1983

[Doppler echographic study of placental circulation of the fetus of normal and hypertensive mothers].

Foetal blood velocity wave forms, as recorded in chorionic vessels by pulsed Doppler ultrasonography, reflect vascular resistance in foetal placental circulation. The minimal-to-maximal velocity ratio provides an index of vascular conductance; the higher the minimal velocity (positive forward diastolic blood flow), the lower the vascular resistance. In the present study, this index was the same in pregnant women with normal blood pressure (n = 19) and in those with pregnancy-induced hypertension (n = 12); however, it was significantly lowered (p less than 0.001) in pregnant women with essential hypertension (n = 9). In the population of women with normal blood pressure and pregnancy-induced hypertension, a positive correlation (r = 0.71), was found between index value and gestational age, indicating a progressive fall in placental vascular resistance. All placentas from these 31 women were histologically normal except two which showed one single marginal infarct less than 1 cm in diameter. In the group of women with essential hypertension, the 6 placentas examined were pathological, with multiple chronic infarcts, placental growth retardation and maceration. Thus, pulsed Doppler ultrasonography should be used for early detection of placental vascular damage and for improved surveillance of pregnancies complicated by maternal vascular diseases.

Blood Flow Velocity↗
PubMed1983

The origin of human B and T cells from multipotent stem cells: a study of the Tn syndrome.

The Tn (or polyagglutinability) syndrome corresponds to a human nonmalignant acquired condition which results from a somatic mutation occurring at the level of bone marrow stem cells. This model offers therefore a unique opportunity to study the contribution of multipotential stem cells to the maintenance of cells from the lymphoid lineage. We found that the Tn mutation is expressed by both myeloid and lymphoid mature blood cells. Whereas a large proportion of surface IgM-bearing B cells carry the Tn mutation, only a small percentage of T cells and IgA- or IgG-bearing B cells are defective, showing that under physiological conditions the penetration of stem cells into the various myeloid and lymphoid compartments is variable.

ABO Blood-Group System↗
PubMed1983

Non-invasive quantification of aortic regurgitation by Doppler echocardiography.

This study was undertaken to assess the contribution of Doppler echocardiography to the quantification of aortic valve regurgitation. Ultrasound examination was performed by recording aortic arch blood flow from the suprasternal notch. A non-invasive index of valve regurgitation was obtained by calculating the ratio between the maximal amplitude of forward flow during systole and the amplitude of retrograde flow during diastole measured at the onset of the R wave of the electrocardiogram. This index was compared with semiquantitative data derived from supravalvular aortography in 93 patients. In pure aortic regurgitation (67 patients) the results showed a high correlation coefficient between Doppler and angiographic estimates. In cases of associated aortic valve stenosis there were problems in the accurate estimation of systolic blood flow which led to global overestimation in general of the degree of regurgitation and considerable lack of precision in individual patients. But in general Doppler echocardiography appeared to be a successful technique to quantify pure aortic regurgitation.

Adolescent↗
PubMed1983

Correlation between velocity measurements from Doppler echocardiography and from M-mode contrast echocardiography.

The slope of an individual contrast trajectory on M-mode contrast echocardiography represents a physiological variable similar to that measured by Doppler echocardiography: the projection of the intracardiac velocity vector in the direction of the sound beam. To test the hypothesis that M-mode contrast echocardiography slope measurement can yield information quantitatively similar to Doppler measurements, we performed both simultaneously in 11 normal volunteers. A pulsed Doppler unit capable of simultaneous M-mode and Doppler display was used. Contrast was obtained by intravenous injection of 5% dextrose. Two independent observers measured velocity simultaneously by both techniques at eight to 16 points per subject. One observer repeated the measurements a month later. All subjects had contrast, and 10 had sufficient quality tracings for simultaneous Doppler and contrast slope measurements. The correlation between velocity measurements by both techniques was good, though velocities by Doppler echocardiography were less than by M-mode contrast echocardiography. We conclude that the component of flow velocity towards or away from the transducer can be measured from M-mode contrast trajectory slopes as well as by Doppler echocardiography. M-mode contrast echocardiography may provide a practical method for verifying or calibrating Doppler measurements in vivo.

Adult↗
PubMed1983

Quantitative assessment of tricuspid regurgitation using pulsed Doppler echocardiography.

Tricuspid valve regurgitation was assessed quantitatively by measuring blood flow velocity in the vena cava using a pulsed Doppler velocimeter. A non-invasive index of regurgitation was obtained by calculating the ratio between the maximum amplitudes of the systolic and diastolic components of the velocity curves. The index was compared with the angiographic grading of regurgitation in 70 patients after right heart catheterisation; the results were closely correlated. Using the Doppler index the differences between the groups defined according to their angiographic grade were significant. Thus measurement of blood flow velocity in the vena cava appears to quantify accurately the severity of tricuspid regurgitation.

Adolescent↗
PubMed1983

[Intravenous subtraction angiography in kidney transplant patients].

Conventional arteriography in patients with kidney transplants and severe hypertension is performed principally to determine the presence of a renal artery stenosis. In patients with renal failure its use enables detection of any arterial lesions. Technological advantages provided by computerized angiography within the field of medical imaging should permit earlier diagnosis of arterial lesions, with a reduced risk and at a lower cost using a simple intravenous injection of the iodized contrast medium.

Adult↗
PubMed1982

Association of human erythrocyte membrane glycoproteins with blood-group Cad specificity.

Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of erythrocyte membranes from a blood-group-B individual with the rare Cad phenotype indicates a lower-than-normal mobility of the main sialoglycoproteins, suggesting an increase in apparent molecular mass of 3kDa and 2kDa respectively for glycoprotein alpha (synonym glycophorin A) and glycoprotein delta (synonym glycophorin B). Since the chief structural determinant of Cad specificity is N-acetylgalactosamine, the membrane receptors have been isolated by affinity binding on immobilized Dolichos biflorus (horse gram) lectin. The predominant species eluted from the gel was the abnormal glycoprotein alpha, whereas in control experiments no material could be recovered from the adsorbent incubated with group-B Cad-negative erythrocyte membranes. After partition of the membranes with organic solvents, the blood-group-Cad activity was found in aqueous phases containing the sialoglycoproteins, but not in the organic phases containing simple or complex glycolipids, which, however, retained the blood-group-B activity. The carbohydrate composition of highly purified lipid-free glycoprotein alpha molecules prepared from Cad and control erythrocytes was determined. Interestingly the molar ratio of N-acetylneuraminic acid to N-acetylgalactosamine was equal to 2:1 in the case of controls and equal to 1:1 in the case of Cad erythrocytes. Taken together these results suggest that Cad specificity is defined by N-acetylgalactosamine residues carried by the alkali-labile oligosaccharide chains attached to the erythrocyte membrane sialo-glycoproteins.

ABO Blood-Group System↗
PubMed1982

Pj variant, a new hybrid MNSs glycoprotein of the human red-cell membrane.

An unusual glycoprotein variant (Pj) was found inherited through a caucasian family exhibiting atypical N and Nvg blood-group reactivities. Pj erythrocytes are blood-group-MS homozygous and have a normal sialic acid content. On sodium dodecyl sulphate/polyacrylamide-gel electrophoresis the variant contains a new component Pj of 24kDa apparent molecular mass in the monomeric state which is sharply stained by periodic acid/Schiff reagent. Both blood-group-MN (alpha) and -Ss (delta) glycoproteins were present. Homodimers (Pj2) as well as heterodimers with MN-glycoprotein (alpha Pj) and the Ss-glycoprotein (delta Pj) were also identified. The new sialoglycoprotein Pj is trypsin- and chymotrypsin-resistant in situ and carries N- and Nvg- but not M- and S-reactivities. The Pj component is labelled by lactoperoxidase-catalysed radioiodination. A 3H label is also easily introduced into the sialic acid or the galactose and galactosamine of the Pj glycoprotein. It is proposed that the Pj is a hybrid glycoprotein containing the N-terminal end of delta-glycoprotein and the C-terminal end of the alpha-glycoprotein. This proposal is supported by the finding that Pj carries a leucine residue at its N-terminus and is not immunoprecipitated by a monoclonal mouse antibody (R18) reacting specifically with the external domain of glycoprotein alpha. The red cells from the proposita Pj were found positive for a very low frequency MN antigen named Sta.

Amino Acids↗