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Biomedical subjects

C Galand

Publications and source records attributed to C Galand.

At least 55 records · Page 3Linked to original sources
PubMed1982

Spectrin beta-chain variant associated with hereditary elliptocytosis.

An electrophoretically fast-moving variant of the spectrin beta-chain was discovered in the erythrocyte membranes of a woman and her father who both exhibited elliptocytosis and mild hemolytic anemia. This abnormal beta'-subunit (Mr = 214,000) co-existed with a decreased normal beta-chain and represented about half of the total beta-chains in the membrane. In contrast to the spectrin beta-chain, the beta'-chain was phosphorylated neither in the membrane by endogenous protein kinases nor in solution by pure membrane casein kinase whether or not the spectrin was dephosphorylated by erythrocyte cytosolic spectrin phosphatase. The presence of the beta'-chain was associated with a defective self-association of spectrin dimer to form tetramer as manifested by: (a) an excess of spectrin dimer in the 4 degrees C spectrin crude extract, (b) a defective self-association of the spectrin dimer in the 37 degrees C crude spectrin extracts. Gel electrophoretic analysis of the tetramer and dimer species isolated from the proband's 4 degrees C extract showed that the tetramer contained trace amounts of the beta'-chain, whereas in contrast, a large proportion of beta'-chain was present in the dimer. These results demonstrated the responsibility of the beta'-chain for the defective reassociation of spectrin dimer into tetramer. The study of this abnormal spectrin confirms the participation of spectrin beta-chain in dimer-dimer association and strongly suggests that the phosphorylation sites of the normal beta-chain are located at the end of the molecule involved in the dimer-dimer interactions.

Adult↗
PubMed1982

Erythrocyte membrane phosphorylation in sickle cell disease.

Phosphorylation of erythrocyte membrane proteins was determined in patients with homozygous sickle cell disease. After incubation of ghosts with gamma-32P ATP, proteins were submitted to SDS-polyacrylamide gel electrophoresis. Three salient features appeared: (i) a decreased phosphorylation of spectrin bands; (ii) a significantly increased phosphorylation (P less than 0.001) of bands 4(5) and 4(8) in the absence of cAMP and (iii) a significantly increased phosphorylation (P less than 0.001) of bands 7 and 8, both in the absence and the presence of cAMP. Studies on reticulocyte rich blood showed that the first change appeared to be specifically related to the disease, whilst the second resulted from the rejuvenation of the red cell population. No definite conclusion could be drawn for the third alteration.

Adolescent↗
PubMed1982

A shortened variant of red cell membrane protein 4.1.

In a healthy 32-yr-old woman with normal red cell morphology, a shortened variant of cytoskeletal membrane protein 4.1 is described at the heterozygous state. One haploid set of protein 4.1 migrates below protein 4.2 and displays a reduction in mass of approximately 8500 with regard to the normal haploid set. The shortening corresponds to a deletion of about 75 amino acids and concerns both subcomponents a and b of protein 4.1. It seems to involve some phosphorylation site(s). It was transmitted to the proposita's son (who inherited elliptocytosis with band 4.1 deficiency from his father). To our knowledge, the present abnormality is the first unequivocal variant of erythrocyte membrane protein 4.1 recognized up to now.

Adult↗
PubMed1982

Narrowband teleradiology.

A narrowband communication system using the Canadian satellite ANIK-B was used to transmit radiographic images from northern Quebec to Montreal. This slow scan television (SSTV) system was used to study the accuracy of the radiologist's interpretation, both with samples of pre-selected films and current patients. Several hours of training in the technique of radiographic interpretation from a static image displayed on a TV monitor was an important factor affecting performance. In selected patients, based on a sample of 124 error-free direct viewing interpretations by four radiologists, SSTV reading by the same fully trained radiologists was correct in 84.5%. With actual patients, and assuming the interpretation from direct viewing to be the correct one, SSTV reading of the radiographs by the same radiologist gave a corresponding figure of 84.1% in a sample of 518 patients containing 73.4% of negative findings, and 89.4% in another sample of 305 patients, including 82% of negative findings. The present error rate on SSTV reading is twice as great as radiographic interpretation using a broadband television system.

Canada↗
PubMed1981

In vitro phosphorylation of the red blood cell cytoskeleton complex by cyclic AMP-dependent protein kinase from erythrocyte membrane.

Hydrosoluble proteins extracted from human erythrocyte ghosts by dialysis at low ionic strength and alkaline pH contain a cyclic AMP-dependent protein kinase which phosphorylates in vitro the cytoskeleton components in crude extracts. Spectrin components 1 and 2, actin and protein band 4.1 undergo this cyclic AMP-dependent endogenous phosphorylation together with low molecular weight peptides solubilized with the cytoskeleton in hydrosoluble extract. However, pure spectrin and purified erythrocyte G-actin were not phosphorylated by purified cyclic AMP-dependent protein kinase from erythrocyte membrane. Purified G-actin when added free to crude extract does not undergo phosphorylation by the cyclic AMP-dependent protein kinase present in this extract. In contrast, purified cyclic AMP-dependent protein kinase added either to crude extract or to the purified cytoskeleton complex (spectrin, actin and protein band 4.1), phosphorylates spectrin, actin and protein band 4.1. We can conclude that (1) cyclic AMP-dependent phosphorylation of red cell cytoskeleton occurs in vitro only when the cytoskeleton components are in a complexed form; (2) red cell actin, like other cellular actins, may be phosphorylated by cyclic AMP-dependent protein kinase but only in the oligomeric form and not in the G form.

Actins↗
PubMed1981

Teleradiology in northern Quebec.

A two-way television network using the Canadian satellite ANIK-B was utilized to transmit radiographic images from Northern Quebec to Montreal. The accuracy of the radiologist's interpretation and his satisfaction with the TV system were studied using a series of 67 preselected cases and 425 current clinical cases. The four participating radiologists gave correct TV interpretations in 81% of the 39 selected cases presented at the beginning of the experiment. This value reached 94% for the other 28 selected cases presented after three months of regular use of the TV system. With current clinical cases, the agreement between TV and direct interpretations was 93%. Although magnification was available, correct identification of very small lesions proved to be the major source of error. On the whole, the radiologists were satisfied with the TV system.

Adult↗
PubMed1981

[Human leukemic-cell protein-kinases. 1 - Non-granulocytic leukemias (author's transl)].

The study of human leukemic-cell protein-kinases is justified by two types of arguments: on one hand, abnormal protein-kinases have been found in various malignancies, and on the other the products of virus transforming genes have repeatedly been identified as protein-kinases. Using cytosolic and particulate extracts of normal human lymphocytes we measured protein-kinase activities, then following partial purification by DEAE and phosphocellulose chromatography the isoenzymes of cyclic AMP dependent and independent protein-kinases and casein-kinases were determined in order to establish a profile (12 normal subjects). The same methodology was applied to the lymphocytes of 5 patients with chronic lymphocytic leukemia (CLL) and 3 patients with acute lymphoblastic leukemia (ALL). Compared to normal lymphocytes, the specific activity of cytosolic and particulate extracts from the leukemics was higher for histone and casein-kinases, following elimination of an inhibitory activity present in the crude extracts. Studies of the isoenzymes showed, in some individuals, the presence in both cytosolic and particulate extracts of two important cyclic AMP dependent histone-kinase activities, which were very low or absent in normal lymphocyte extracts. In the particulate extracts we found a constant increase in casein-kinase activities concerning essentially one of the two isoenzymes present. Also, the ratio of the different isoenzymes separated by chromatography was considerably modified with regard to both histone and casein-kinases. These quantitative and qualitative abnormalities were present in some CLL cells and in non-granulocytic acute leukemic cells. They resembled the modification reported during normal lymphocyte stimulation by phytohemagglutinin, and also seemed to reflect the intensity of cellular replication and to some degree the progression of the disease.

Casein Kinases↗
PubMed1980

Phosphorylation of human red cell and liver pyruvate kinase. Differences between liver and erythrocyte L-type subunits.

Purified PK from human erythrocyte was phosphorylated by cAMP-dependent protein kinase type I from human erythrocyte membrane; this phosphorylation affected only the 'heavy L' subunit but not the L subunit. On the other hand, the L subunit of liver PK was highly phosphorylated. Thus it appears that the L subunits from erythrocyte and liver PK are not identical protein molecules.

Erythrocytes↗
PubMed1979

Altered erythrocyte membrane protein phosphorylation in an unusual case of hereditary spherocytosis.

Membrane protein phosphorylation was examined in several members from a family with an unusual form of hereditary sperocytosis. After incubation of membrane ghosts with (gamma-32 P) ATP, the phosphorylation of spectrin component II was diminished both in the absence of cAMP. In the presence of this nucleotide, the phosphorylation of components IV5 and IV8 was also decreased. Along with a previously reported alteration of a membrane neutral phosphatase in this family, these abnormalities remove the present condition from the usual form of hereditary spherocytosis.

Cyclic AMP↗
PubMed1978

[Glutathion-synthetase deficiency with 5-oxoprolinuria. Two new cases and a review of the literature (author's transl)].

Hereditary deficiency in glutathion- synthetase is a rare disease presenting up to now either with a congenital non-spherocytic anaemia or with a metabolic acidosis, most often neonatal and accompanied by a pyroglutamic amino-aciduria (5-oxoprolinuria). These two syndrome may be present together or exist independently. Pyroglutamic amino-aciduria is the result of extension of the deficiency to non-haematopoietic cells, in particular renal. Two new cases of glutathion-synthetase deficiency are reported: both with haemolytic anaemia and moderate pyroglutamic amino-aciduria, in the absence of clinical signs of metabolic acidosis. The clinical, haematological and biochemical heterogeneity of the deficiency is illustrated by these two cases and datas from the literature.

Anemia, Hemolytic, Congenital↗
PubMed1978

A new variant of glucosephosphate isomerase deficiency with mild haemolytic anemia (GPI-MYTHO).

A new case of glucosephosphate isomerase deficiency with mild haemolytic anaemia was observed in a 6-year-old girl. Deficient enzyme was characterized by a profoundly decreased activity in the red cells, a normal electrophoretic phenotype, normal isoelectric point, normal optimum pH, a molecular instability and a clearly decreased Michaelis constant for fructose-6-phosphate. Propositus was double heterozygote for a 'silent gene' inherited from the mother and an abnormal enzyme from the father. Because this abnormal enzyme has undescribed characteristics, it responds to a new variant for which we propose the name GPI-MYTHO.

Anemia, Hemolytic↗