Connective tissue activation. XX. Stimulation of prostaglandin secretion by mediators from lymphocytes (CTAP-I) and platelets (CTAP-III).
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Animals↗
Biomedical subjects
C W Castor
Publications and source records attributed to C W Castor.
Connective tissue activation in guinea pig lung fibroblast cultures: regulatory effects of glucocorticoids.
Earlier studies showed that guinea pig lung fibroblasts in cell culture could be "activated" by naturally occurring peptides with a resultant increase in glycolysis and glycosaminoglycan formation. Such connective tissue activation (CTA) in human cell systems (synovial, cartilage, dermal) has proved a useful tool for studying the mechanisms of inflammation and dissecting the efficacy and actions of anti-inflammatory drugs. The present study examined the consequences of treating basal and activated guinea pig lung fibroblasts with glucocorticoids. The data indicate that glucocorticoids minimally suppress glycosaminoglycan (GAG) synthesis in nonactivated cultures. Further, CTA was inhibited to only a minor degree in activated lung fibroblast cultures by steroids, and even markedly supraphysiologic concentrations of glucocorticoids were not notably inhibitory. It was of interest that thiols enhanced suppression of incremental GAG synthesis by some glucocorticoids in activated lung fibroblast cultures.
Animals↗
Connective tissue activation. XXI. Regulation of glycosaminoglycan metabolism by lymphocyte (CTAP-I) and platelet (CTAP-III) growth factors.
The quantitative radiochemical methodology described in this report allows a major increase in information generation, increased experimental flexibility, improved statistical control, and increased diversity of information per culture. Other advantages relate to economies of technical time, supplies, cells, and test materials per individual culture. Microcultures of human synovial cells incorporate [14C]glucosamine into hyaluronic acid that accumulated primarily in the media and to a lesser extent in the cell mass. CTAP-I (from lymphoid cells), CTAP-III (from human platelets), PGE2, dibutyryl cAMP, and poly(I) . poly(C) markedly stimulated hyaluronate synthesis, whereas cortisol, cycloheximide, and tunicamycin inhibited stimulated synthesis. Time studies with cycloheximide indicated that translation, essential for the activation of synovial cells, was completed by 17 h postexposure to CTAP-I. Tunicamycin also seemed to inhibit CTAP-I induced activation primarily by interfering with translation; however, tunicamycin also caused modest post-translation inhibition of hyaluronate synthesis in activated adult human synovial cells.
Blood Platelets↗
Connective tissue activation. XXII. A platelet growth factor (connective tissue-activating peptide-III) in human growth hormone-deficient patients.
Connective tissue-activating peptides (CTAPs) stimulate human synovial cells to exhibit a higher rate of DNA synthesis, glycolysis, and glycosaminoglycan formation. These bioactive peptides have been isolated from human platelets (CTAP-III), lymphocytes, tumor cells, and neutrophilic leukocytes. Several other growth factors, such as somatomedins A and C and nonsuppressible insulin-like activity (soluble), have been shown to be dependent on the circulating levels of pituitary GH. In this study, we examined the human GH (hGH) dependence of CTAP-III. Platelets from children with reduced or absent hGH were examined for the presence of CTAP-III. The peptide was detected qualitatively by polyacrylamide gel electrophoresis and Ouchterlony double diffusion. CTAP-III antigen, measured by RIA, was found in normal amounts in platelet lysates from normal persons and GH-deficient patients. Biological activity of the peptide was suggested by the ability of platelet lysates to stimulate the formation of glycosaminoglycans and increase sulfate incorporation into glycosaminoglycans formed in cell cultures. In addition, normal and hGH-deficient platelet lysates contained potent mitogenic activity which increased thymidine incorporation into DNA. Platelets from GH-deficient patients also released CTAP-III normally on exposure to thrombin.
Adolescent↗
Connective tissue activation. XVII. Radioimmunoassay of a human platelet derived connective tissue activating peptide (CTAP-III) and specificities of anti-CTAP-III sera.
The platelet-derived connective tissue activating peptide (CTAP-III) has been shown to be an important factor stimulating the metabolism and proliferation of human connective tissue cell strains, including synovial tissue cells. The quantities of CTAP-III affecting the cellular changes and the amounts of various biologic fluids and tissues are small. The objectives of this study were to develop a radioimmunoassay (RIA) for CTAP-III and to ascertain the specificities of the anti-CTAP-III sera reagents. The antisera were shown not to cross-react with a number of polypeptide hormones. However, two other platelet proteins, beta-thromboglobulin and low affinity platelet factor-4, competed equally as well as CTAP-III for anti-CTAP-III antibodies in the RIA system. Thus, the three platelet proteins are similar or identical with respect to those portions of the molecules constituting the reactive antigenic determinants. The levels of material in normal human platelet-free plasma that inhibited anti-CTAP-III--125I-CTAP-III complex formation were determined to be 34 +/- 13 (S.D.) ng/ml.
Animals↗
Connective tissue activation. XV. Stimulation of glycosaminoglycan and DNA synthesis by a polymorphonuclear leukocyte factor.
Human synovial fibroblasts in culture have been stimulated to augment hyaluronate synthesis and glucose utilization by connective tissue activating peptides (CTAP) extracted from human spleen, lymphocytes, platelets, granulocytes, and tumour cells. The platelet-derived mediator CTAP-III also stimulated DNA synthesis in synovial fibroblasts, but CTAP-I from lymphocytes and spleen did not. The present study demonstrates the mitogenic potential of a granulocyte mediator (CTAP-PMN). Normal granulocytes were prepared with Ficoll-diatrizoate gradients, platelet contamination being estimated by phase microscopy and by radioimmunoassay for the platelet-specific protein, beta-thromboglobulin. CTAP-PMN preparations derived from 4 x 10(7) cells/ml stimulated culture 3H-thymidine incorporation to 3.56 +/- 1.32 (SD) times control levels. Although exposure of preparations to thiols reduced their mitogenicity, CTAP-PMN was relatively heat-stable. SDS gel electrophoresis of active fractions suggested a molecular weight between 12,700 and 15,700 daltons. In double immunodiffusion, antisera to CTAP-III showed no reactivity with CTAP-PMN. CTAP-PMN or other granulocyte factors capable of stimulating fibroblast DNA synthesis may play a role in chronic proliferative synovitis or in other settings where exudative inflammation is accompanied by connective tissue growth.
Connective Tissue↗
Connective tissue activation. XVI. Detection of a human platelet-derived connective tissue activating peptide (CTAP-III) in human sera and plasma and in synovial fluids and tissues.
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Blood Platelets↗
Connective tissue activation. XVIII. Stimulation of hyaluronic acid synthetase activity.
Human synovial fibroblasts synthesize hyaluronic acid, a process that can be stimulated by a number of agents. Several steps in the synthetic pathway could be the locus at which these stimulators act; the final step, promoted by hyaluronic acid synthetase, was selectd for study. Hyaluronic acid synthetase is an enzyme system that transfers monosaccharide units to nascent hyaluronic acid chains. Activities of the enzyme were determined in lysates of cultured synovial fibroblasts by measuring incorporation of 14C-UDP-glucuronic acid into hyaluronic acid. Rates of hyaluronic acid synthesis were increased by adding CTAP-I or CTAP-III, DbcAMP, or prostaglandin E2 to the cultures. In each instance, hyaluronic acid synthetase activity was enhanced in a manner comparable to that seen in hyaluronic acid synthesis. The changes in enzyme and product were observed as early as 6 hr after cultures were exposed to CTAP-III, and both indices declined when this stimulator was withdrawn for 24 hr. Although DbcAMP incrased the hyaluronic acid synthetase activity of intact fibroblasts, it had no effect on the enzyme in lysates of cells. In the cultured cells, cycloheximide reduced basal levels of synthetase activity and hyaluronic acid synthesis of hyaluronic acid may do so by inducing hyaluronic acid synthetase.
Connective Tissue↗
Connective tissue activation. XIV. Composition and actions of a human platelet autacoid mediator.
Connective tissue activating peptide-III (CTAP-III) isolated from human platelets is a potent mitogen for human connective tissue cells in culture in addition to stimulating glycosaminoglycan synthesis, glucose consumption, and lactate formation. The amino acid composition of apparently homogeneous CTAP-III was determined, confirming the presence of two disulfide links and providing a calculated molecular weight of 11,633 daltons. Comparison of the mitogenic activity of serum and plasma-serum suggests that CTAP-III is a major mitogenic component of human serum. Seventeen strains of human connective tissue cells (synovial, cartilage, dermal and thyroid) incorporated [3H]-thymidine at up to 30 times control at levels under the influence of microgram quantities of CTAP-III and caused detectable increases in thymidine incorporation at levels as low as 10-29 ng/ml. Prostaglandin E1 (0.01 microgram/ml) and dibutyryl cyclic AMP (25 microgram/ml) potentiated the glycosaminoglycan stimulating effect of CTAP-III, but not its mitogenic effect. Cycloheximide and actinomycin D blocked the biologic actions of CTAP-III. Cortisol and penicillamine had little effect on the mitogenic activity of CTAP-III, whereas antirheumatic agents such as acetylsalicylic acid and phenylbutazone opposed the mitogenic activity when added to cultures at clinically relevant concentrations. A weak antiheparin factor secreted by platelets, low affinity platelet factor 4 (LA-PF4), was shown to be similar to CTAP-III in biologic actions, electrophoretic mobility, amino acid composition, and antigenic determinants.
Amino Acids↗
Activation of lung connective tissue cells in vitro.
Guinea pig lung fibroblasts "activated" in vitro by exposure to connective tissue-activating peptides I and III, and guinea pig tissue extracts showed enhanced glycolysis and accelerated glycosaminoglycan synthesis. Formation of hyaluronic acid, and to a lesser extent, chondroitin 4/6-sulfate was stimulated by these agents.
Animals↗
Connective tissue formation by lung fibroblasts in vitro.
Guinea pig lung fibroblasts were grown in monolayer culture after enzymatic disaggregation of lung parenchyma. Light and electron microscopy indicated that the cultures were relatively homogeneous with respect to cell type. Synthesis of matrix glycosaminoglycans and collagen was demonstrated throughout the life of the culture. The properties of the guinea pig cell strains make these a suitable in vitro model system for studying the regulation of connective tissue metabolism of pulmonary tissue.
Animals↗
Pseudogout associated with meniscal cysts - report of two patients.
Two patients with pseudogout developed large meniscal cysts at the knee. In the first case the diagnosis of meniscal cyst was confirmed surically. In the second case, the cyst resolved following thorough aspiration. Polarized microscopy of repeated aspirated from cyst in this case as well as of fluids from the knees of both patients consistently showed positively birefringent rhomboid crystals. X-ray diffraction of fluids from the knee of the second patient identified the crystals as calcium pyrophosphate dihydrate.
Aged↗
Connective tissue activation. XIII. Stimulation of sulfated glycosaminoglycan synthesis in human connective tissue cells by peptide mediators from lymphocytes and platelets.
CTAP-I from lymphocytes and CTAP-III from platelets markedly stimulated 35SO4= incorporation into chondroitin 4/6 sulfate and dermatan sulfate synthesized by human synovial, dermal, and cartilage connective tissue cells in vitro. These agonists promoted synthesis of the GAG carbon chain as well as sulfate incorporation. Both RNA and protein synthesis were required for these mediators to be effective in stimulating synthesis of connective tissue matrix components. A major part of the capacity of normal serum to stimulate sulfate incorporation into GAG's may reside in CTAP-III.
Blood Platelets↗
Connective tissue activation. XII. Platelet abnormalities in patients with rheumatoid arthritis.
Patients with rheumatoid arthritis frequently have an unexplained thrombocytosis which appears to be related to the severity of the disease process. This report shows that rheumatoid platelets have reduced saline soluble protein per 10(9) platelets, less of a lysosomal enzyme, acid phosphatase, and decreased connective tissue activating peptide (CTAP-III) activity. CTAP-III is a potent connective tissue mitogen, and promotes glycolysis and glycosaminoglycan synthesis, characteristics which make it an interesting candidate for a role as a mediator of inflammation.
Acid Phosphatase↗
Connective tissue activation. XI. Stimulation of glycosaminoglycan and DNA formation by a platelet factor.
This report describes a small basic protein found in human platelets which stimulates hyaluronic acid formation, glucose uptake, and lactate formation in several types of human connective tissue cells. In addition, it stimulates in incorporation of [3H] methyl thymidine into DNA in human synovial cell cultures. This platelet factor (connective tissue activating peptide-II, CTAP-III) clearly differs form CTAP-I, found in human lymphocytes, and may play a role as a mediator of the inflammatory process.
Blood Platelets↗
Measurement of urinary and serous-fluid glycosaminoglycans and urinary hydroxyproline.
Although analytic measurements of connective tissue components in biological fluids would frequently be useful in diagnosis and/or management of many inflammatory, neoplastic and metabolic diseases, such information is often unavailable due to the methodologic problems posed by these natural products. This report outlines relatively simple procedures leading to the colorimetric measurement of glycosaminoglycans in urine and other body fluids and to measurement of hydroxyproline in urine. Normal values and potential applications are presented.
Ascitic Fluid↗
Characteristics of an antigen reactivity in synovial fluids and its association with rheumatoid arthritis.
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Antigens↗
Connective tissue activation: VIII. The effects of temperature studied in vitro.
The effects of increasing environmental temperature were studied in two normal and two rheumatoid human synovial cell cultures. Control cultures showed an increased rate of hyaluronate synthesis and glucolysis as temperature was increased from 30 C to 39 C. Cultures which were activated (stimulated by a connective tissue activating peptide, CTAP) showed an especially striking increase in hyaluronic acid synthesis, glucose uptake and lactate formation at 36 C and 38 C. The data suggest that small changes in joint temperature may be associated with profound alterations in synovial metabolic activity.
Arthritis, Rheumatoid↗