Subject(s)
Red-Cell Aplasia, Pure/blood , Stem Cell Factor/blood , Biomarkers , Erythropoiesis , Female , Humans , MaleABSTRACT
Stem cell factor (SCF) is a recently described factor active in the early stages of hematopoiesis. It can exist in membrane-bound form and in proteolytically released soluble form. The levels and nature of SCF in human serum are described. As determined by an enzyme-linked immunosorbent assay performed for 257 samples, SCF level in serum averaged 3.3 +/- 1.1 ng/mL. The serum SCF was partially purified by immunoaffinity chromatography and analyzed by glycosidase treatments in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The results show that the SCF has N-linked and O-linked carbohydrate and corresponds to the soluble form, at or about 165 amino acids in length. The findings suggest functional importance for soluble SCF in humans.
Subject(s)
Hematopoietic Cell Growth Factors/blood , Adult , Age Factors , Cells, Cultured , Chromatography, Affinity , Colony-Forming Units Assay , Dose-Response Relationship, Drug , Electrophoresis, Polyacrylamide Gel , Enzyme-Linked Immunosorbent Assay/methods , Erythropoietin/pharmacology , Female , Hematopoietic Cell Growth Factors/isolation & purification , Hematopoietic Cell Growth Factors/pharmacology , Humans , Immunoglobulin G , Leukocytes/cytology , Leukocytes/drug effects , Male , Middle Aged , Recombinant Proteins/pharmacology , Reference Values , Sex Characteristics , Stem Cell FactorABSTRACT
Creatine kinase (CK) and lactate dehydrogenase (LD) enzyme activities and isoenzymes were determined for synovial fluid, synovial membrane, and articular cartilage from 24 clinically normal equine tarsocrural (tibiotarsal) and femoropatellar joints. All 3 tissues contained LD isoenzymes LD1 to LD5, and CK isoenzymes BB and MM. The CK isoenzyme MB was not found. The similarities in isoenzyme composition of these 3 tissues made differentiation of the source of LD and CK impossible by isoenzyme pattern alone. Reference values for the total enzyme activities of specific joint tissues also had wide variations. The wide variation in activities, as determined by the enzymatic analysis of synovial fluid and a lack of tissue specificity in clinically normal equine joint tissue, indicated that those values were not predictive for the extent and type of tissue damage in equine joint disease. This hypothesis was confirmed when synovial fluids from 22 abnormal joints were analyzed for LD isoenzymes and total enzyme activity. The various causes of the joint problems were not distinguishable.
