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Biomedical subjects

C Boyer

Publications and source records attributed to C Boyer.

At least 127 records · Page 7Linked to original sources
PubMed1982

Treatment of congenital antithrombin III deficiency with concentrates.

Antithrombin III concentrates were administered to a patient with hereditary AT III deficiency undergoing orthopaedic surgery. The plasma AT III level (heparin cofactor activity) was maintained at values in excess of 100% postoperatively. A mean dose of 0.74 u/kg (range 0.64 - 0.83) of AT III resulted in a 1% increase in AT III level after concentrate infusion. The half-life of AT III (mean 66 h; range 58-76) was shorter during surgery and in the early postoperative period suggesting an increased consumption of the inhibitor. At III antigen was consistently higher than heparin cofactor activity during the first 24 h after concentrate infusions. This discrepancy was associated with the presence in the patient's plasma of an AT III fraction showing a slower mobility than the main AT III peak on two-dimensional immunoelectrophoresis in the presence of heparin. A biological assay is preferred to an immunological assay in monitoring replacement therapy with AT III concentrates.

Adult↗
PubMed1982

A new familial variant of antithrombin III: 'antithrombin III Paris'.

A 59-year-old woman presented a recurrent history of thromboembolism. A qualitative defect of antithrombin III (AT III) was suggested by the discrepancy between a normal amount of AT III antigen and a decreased heparin cofactor activity. Six members of the same family showed a similar defect although clinically asymptomatic. The qualitative abnormality of AT III was confirmed by two-dimensional immunoelectrophoresis. In the absence of heparin, a single peak was obtained with both control and patients' plasmas. In the presence of heparin, two peaks of AT III were observed in the patients' plasmas: the mobility of one peak was similar to that of the control, whereas the other showed a decreased mobility, suggesting a lack of binding to heparin. The two populations of AT III were separated by affinity chromatography on heparin-agarose. 50% of the patients' AT III bound to the agarose beads. The remainder, recovered in the supernatant, migrated in two-dimensional immunoelectrophoresis as a single peak with the same mobility in the presence or absence of heparin, and was devoid of heparin cofactor activity. This familial AT III variant characterized a reduced affinity for heparin is tentatively named 'Antithrombin III Paris'.

Antigens↗
PubMed1982

Immunological characterization of Escherichia coli B glycogen synthase and branching enzyme and comparison with enzymes from other bacteria.

Escherichia coli B glycogen synthase and branching enzyme, although similar in amino acid composition, had no significant immunological cross-reactivity. The N-terminal sequences of the glycogen synthase were rich in hydrophobic residues, whereas branching enzyme had a higher content of acidic and basic residues. However, residues 21 to 28 of glycogen synthase and 7 to 14 of branching enzyme shared six of eight residues in common. Two fractions of branching enzyme, branching enzymes I and II, which can be isolated from E. coli B cell extracts, have been shown to be immunologically identical, suggesting that only one type of branching enzyme activity is present in E. coli B. Evidence has been obtained which indicates that E. coli B glycogen synthase and branching enzyme are antigenically very similar to glycogen synthases and branching enzymes from other enteric bacteria. No cross-reactivity with either enzyme was observed in cell extracts from photosynthetic bacteria.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1979

Long-term results of permanent atrioventricular sequential demand pacing.

Pervenous atrioventricular sequential demand pacemakers (AVSDPs) were implanted in 18 patients using an atrial electrode positioned in the right atrial appendage and a ventricular electrode positioned at the apex of the right ventricle. The indications included 13 patients with the sick sinus syndrome (72%), five of whom had the tachycardia-bradycardia syndrome, three with paroxysmal supraventricular tachycardia, one with cardiomyopathy and one with carotid sinus syncope. The follow-up ranged from 6 to 38 months, with a mean of 19.4 months (a total of 350 pacing months). Seventeen patients (94%) are asymptomatic. One patient had persistent episodes of paroxysmal supraventricular tachycardia. In the remaining patients with tachyarrhythmia, pacing alone (three patients) or in combination with antiarrhythmic drugs (four patients) controlled the tachyarrhythmia. There was one displacement of the atrial electrode (5.5%). Extrusion of the pacer occurred in three patients. It is concluded from this experience that AV sequential pacing is an effective technique and may be useful in patients with sick sinus syndrome, in patients with tachyarrhythmia and/or patients with poor myocardial function. However, continued research is needed to prolong battery life and to reduce the size of the pacemaker.

Aged↗
PubMed1977

Haemostatic disorders and respiratory distress in the newborn.

Coagulation and fibrinolysis studies were performed on 64 newborns; 16 premature infants with hyaline membrane disease (HMD), 17 newborns with other forms of respiratory distress syndrome (RDS) (8 of them were premature), 31 healthy newborns (11 of them were premature). All the babies were studied once in the first 48 hours of life. There was no significant difference between sick and healthy babies for 5 parameters; platelet count, factor VIII, fibrinogen, fibrin(ogen) degradation products, euglobulin lysis time. Factor II, VII and X were low in all infants, and premature infants had significantly lower levels compared to full term newborns. Factor V, plasminogen, alpha 2 macroglobulin (alpha 2M) and antithrombin III (AT III) levels were significantly lower in sick infants. Except for AT III, these deficiencies were not related to prematurity. No significant difference was found between HMD and other RDS. Of the 33 sick infants, 5 developed laboratory findings consistent with disseminated intravascular coagulation (DIC). The results indicate that the coagulation and fibrinolytic abnormalities reported are not specific to HMD.

Antithrombins↗
PubMed1977

Immunologic study of the age-related loss of activity of six enzymes in the red cells from newborn infants and adults--evidence for a fetal type of erythrocyte phosphofructokinase.

Blood from 10 normal healthy adults and cord blood from 8 healthy full term infants were infiltrated through a mixture sulfoethylethycellulose-Sephadex G 25 in order to eliminate the platelets and the leukocytes. Then the erythrocytes were fractionated into young and old cells by centrifugation in microhematocrit tubes. The enzyme activity and the immunologic reactivity of glucose phosphate isomerase (EC.5.3.1.9), phosphoglycerate kinase (EC.2.7.2.3), pyruvate kinase (ec.2.7.1.40), glucose 6-phosphate dehydrogenase (EC. 1.1.1.49), and 6-phosphogluconate dehydrogenase (EC.1.1.1.44) were measured in every fraction. As previously reported, the enzyme activities were far higher in cord blood than in adult blood red cells; nevertheless, the age-related loss of enzyme activity was similar in both cord and adult blood. The decrease of the enzyme activity of glucose phosphate isomerase and phosphoglycerate kinase in old cells was singly associated with a lowered concentration of the enzyme-related antigen; by contrast, the age-related decrease of the enzyme activity of pyruvate kinase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase was associated with both a lowered concentration of the enzyme-related antigen and a lowered "molecular specific activity" (i.e., a lowered ratio of enzyme activity to enzyme-related antigen concentration). This phenomenon was especially marked for pyruvate kinase, which had a molecular specific activity in old cells that was 68% of that in young cells. Phosphofructokinase had a lower enzyme activity in cord blood erythrocytes than in adult blood erythrocytes; the difference was especially important in old cells from infants in which phosphofructokinase activity was 53% of that in old cells from adults. Phosphofructokinase from old cells of full term infants and from unfractionated cells from two premature infants (21 and 32 weeks of gestation) was less neutralized by anti-muscle phosphofructokinase serum and more inhibited by ATP than the enzyme from adult blood erythrocytes.

Adenosine Triphosphate↗
PubMed1976

Causal mechanisms of multiple acquired red cell enzyme defects in a patient with acquired dyserythropoiesis.

A patient with an unclassified form of acquired dyserythropoiesis was found to have multiple defects in erythrocyte enzyme activity, involving especially pyruvate kinase (PK), glucose phosphate isomerase (GPI), and phosphofructokinase (PFK). The PK activity defect was associated with a normal concentration of PK-related antigen, and the enzyme could be reactivated during the procedure of partial purification of the enzyme. The concentration of GPI-related antigen was as reduced as the GPI enzymatic activity, and the defect was not improved by any treatment (cross-incubation of red cells or treatment of the hemolysate by SH reagents); the residual enzyme had a normal stability to heat, and a normal electrophoretic and electrofocusing pattern. The PFK activity defect was not improved either by cross-incubation of red cells or by treatment with SH reagents. Immunologic data with antimuscle and antileukocyte antisera seemed to indicate that the defect involved especially the muscle-type subunit of erythrocyte PFK. In agreement with this assumption was the fact that deficient PFK was markedly more inhibited by ATP than normal enzyme. Changes similar to those of deficient PFK herein studied were noted for PFK of unfractionated erythrocytes from premature newborns or of "old" erythrocytes from full-term infants. It appeared that each of the three enzyme defects detected in the patient could be due to a different mechanism, involving post-translational changes, decreased synthesis, and possible reversion of the genetic regulation mechanisms of the abnormal erythroid precursors toward a fetal type. The possible relationships between these various phenomena and the nature of a hypothetical common underlying cause are discussed.

Anemia, Hemolytic, Congenital Nonspherocytic↗