Metabolism of the Third Component of Complement (C3) in Normal Human Subjects

1974 ◽  
Vol 46 (2) ◽  
pp. 223-229 ◽  
Author(s):  
J. A. Charlesworth ◽  
D. Gwyn Williams ◽  
E. Sherington ◽  
D. K. Peters
Keyword(s):  
Human Subjects ◽  
Normal Subjects ◽  
Primary Site ◽  
Biologically Active ◽  
Complement C3 ◽  
The Third ◽  
Plasma Pool ◽  
Normal Human ◽  
C3 Metabolism ◽  
Third Component Of Complement

1. A single, biologically active, highly purified preparation of the third component of complement (C3) has been used to study C3 metabolism in eleven normal subjects. 2. Half-life of the radioactive protein ranged from 64 to 81 h with fractional catabolic rates (FCR) of 1·36–1·95% of the plasma pool/h. Extravascular/intravascular pool ratios were 0·19–0·55. 3. Analysis of plasma and extravascular radioactivity curves suggested that the primary site of C3 metabolism was intravascular.

scholarly journals The mechanism of action of the C3b inactivator (conglutinogen- activating factor) on its naturally occurring substrate, the major fragment of the third component of complement (C3b)

1975 ◽  
Vol 141 (5) ◽  
pp. 1221-1226 ◽  
Author(s):  
JD Gitlin ◽  
FS Rosen ◽  
PJ Lachmann
Keyword(s):  
Alternative Pathway ◽  
Fluid Phase ◽  
Complement C3 ◽  
Classical Pathway ◽  
Physiological Mechanisms ◽  
The Third ◽  
Immune Adherence ◽  
Normal Human ◽  
Molecular Nature ◽  
Third Component Of Complement

The fixation of the third component of complement (C3) results in many important biological phenomenon, among which are (a) immune adherence (1), (b) enhancement of phagocytosis (2,3), (c) the release of an anaphylatoxin which is a potent releaser of histamine (4), and (d) the feedback activation of the alternative pathway (5,6). The physiological mechanisms involving C3 fixation require the generation of a C3 convertase which may occur by two separate pathways. C3 convertase can be generated, in the form of C42, by the so-called classical pathway of activation or in the form C3b,B by the alternative or properdin pathway (7). In both cases, C3 is converted to C3b by cleavage of a small peptide, C3a. Normal human serum contains an inactivator of activated C3b. This C2b inactivator or conglutinogen-activating factor (KAF) has been shown to inhibit both immune hemolysis and the immune adherence properties of C3b and to cause cleavage of C3b in the fixed and fluid- phase stages (8-11). Although it is known that the C3b inactivator is not depleted during its reaction with C3b and that C3b treated with the C3b inactivator becomes extremely sensitive to proteolytic digestion by trypsin and trypsin-like enzymes (9), the exact molecular nature of the action of the C3b inactivator on C3b has not been studied. In an effort to delineate the products of this interaction, purified C3b and C3b inactivator were allowed to react for various specific lengths of time and the products of these reactions were then analyzed.

scholarly journals THE BIOLOGIC SIGNIFICANCE OF THE THIRD COMPONENT OF COMPLEMENT (C3) IN NONIMMUNE HOST DEFENSES

1974 ◽  
Vol 8 (4) ◽  
pp. 421-421
Author(s):  
Jerry A Winkelstein ◽  
Mary Ruth Smith ◽  
Hyun S Shin ◽  
David H Carver
Keyword(s):  
Complement C3 ◽  
Host Defenses ◽  
The Third ◽  
Third Component Of Complement

scholarly journals Metabolism of the third component of complement (C3) in patients with rheumatoid arthritis

1972 ◽  
Vol 15 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Arthur Weinstein ◽  
Keith Peters ◽  
David Brown ◽  
Rodney Bluestone
Keyword(s):  
Rheumatoid Arthritis ◽  
Complement C3 ◽  
The Third ◽  
Third Component Of Complement

Family studies on the third component of complement (C3), 6h1-antitrypsin polymorphism (locus E1 and E2) in the area of Marburg (Germany)

1972 ◽  
Vol 17 (1) ◽  
pp. 85-87 ◽  
Author(s):  
H. W. Goedde ◽  
L. Hirth ◽  
H. -G. Benkmann ◽  
S. Singh ◽  
G. G. Wendt
Keyword(s):  
Family Studies ◽  
Complement C3 ◽  
The Third ◽  
Third Component Of Complement

Platelet catecholamines and platelet function in normal human subjects

1987 ◽  
Vol 73 (1) ◽  
pp. 99-103 ◽  
Author(s):  
A. P. Wilson ◽  
C. C. T. Smith ◽  
B. N. C. Prichard ◽  
D. J. Betteridge
Keyword(s):  
Platelet Function ◽  
High Performance ◽  
Human Subjects ◽  
Normal Subjects ◽  
Noradrenaline Content ◽  
Collagen Concentration ◽  
Normal Human ◽  
Wall Interaction ◽  
Local Release

1. We have used high-performance liquid chromatography with electrochemical detection to measure plasma and platelet catecholamines in 24 normal subjects. 2. In the same subjects platelet function was assessed by measuring platelet aggregation in response to adenosine 5′-pyrophosphate, thrombin, adrenaline and collagen. Platelet sensitivity to prostacyclin was also examined. 3. Platelet noradrenaline showed a positive correlation with extent of aggregation induced by ‘low-dose’ collagen (1 μg/ml). No correlation was seen at the higher collagen concentration. 4. Platelet noradrenaline content also correlated with sensitivity of platelets to prostacyclin. High platelet noradrenaline concentrations appeared to result in decreased sensitivity to prostacyclin. 5. No other correlations were observed. 6. These data suggest that platelet noradrenaline rather than plasma levels may be involved in modifying platelet function in vivo. Local release of platelet catecholamines may affect the platelet/vessel wall interaction, the primary physiological step in platelet activation.

scholarly journals Biosynthesis of the third component of complement (C3) by the human monocytic-cell line U-937 Induction by phorbol myristate acetate

1986 ◽  
Vol 239 (3) ◽  
pp. 711-716 ◽  
Author(s):  
S Bengio ◽  
D Gilbert ◽  
P Peulve ◽  
M Daveau ◽  
M Fontaine
Keyword(s):  
Phorbol Myristate Acetate ◽  
Complement C3 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Haemolytic Activity ◽  
Subunit Structure ◽  
Single Chain ◽  
Myristate Acetate ◽  
Monocytic Cell ◽  
The Third ◽  
Third Component Of Complement

Phorbol myristate acetate (PMA)-stimulated human monocyte-like cells (U-937) were found to synthesize the third component of complement (C3), as shown by enzyme-linked immunosorbent assay and immunoprecipitation from [35S]methionine-labelled culture supernatants. C3 synthesis occurred at a rate of about 160 ng of C3/24 h per 10(6) cells on day 7 after addition of PMA; it was blocked by cycloheximide treatment and was restored after removal of the inhibitor. SDS/polyacrylamide-gel-electrophoretic analysis of the immunoprecipitated protein showed that the size and subunit structure of the newly synthesized C3 were identical with those of plasma C3, and that a single-chain intracellular precursor was present in the cell lysates. Haemolytic assays showed that the synthesized C3 fully expressed functional activity in early culture within 4 h. After longer culture, a loss of haemolytic activity was observed. The possibility that newly secreted C3 is cleaved by U-937 cells themselves was suggested.

Catechol O-Methyltransferase in Red Blood Cells of Schizophrenic, Depressed, and Normal Human Subjects

1976 ◽  
Vol 128 (2) ◽  
pp. 184-187 ◽  
Author(s):  
Helen L. White ◽  
Malcolm N. McLeod ◽  
Jonathan R. T. Davidson
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Human Subjects ◽  
Normal Subjects ◽  
Enzyme Preparations ◽  
Human Red Blood Cells ◽  
Schizophrenic Patients ◽  
Normal Human ◽  
The Mean ◽  
Isoelectric Ph

SummaryCatechol O-methyltransferase of lysed human red blood cells was assayed under optimal conditions, using saturating concentrations of the substrates, S-adenosyl-L-methionine and 3,4-dihydroxybenzoic acid. The mean enzyme activity found in 24 normal subjects was 29.2 nmol/hr/ml RBC. The mean activity in blood of 33 female unipolar depressives was not significantly different from normal. However, higher enzyme activities were observed in the blood of 11 schizophrenic patients (38.9 nmol/hr/ml RBC). Partially purified enzyme preparations from blood of normal and schizophrenic individuals were indistinguishable with respect to substrate specificities, isoelectric pH values, and ratios of the two O-methylated products. Therefore it is unlikely that any defect in O-methylation which may occur in schizophrenia can be attributed to a change in the intrinsic properties of erythrocyte catechol O-methyltransferase.

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