RESUMO
In vitro conditions affecting synthesis of sulfated proteoglycans by cell suspensions derived from monolayer cell cultures of normal and rheumatoid synovial tissue were examined. The capacity of cells to synthesize proteoglycans was estimated by the incorporation of 35S--sulfate into cetylpyridinium chloride--precipitable material. Synthesis of sulfated proteoglycans was maximal during log phase, and after 2--3 hours of recovery from disaggregation. Normal synovial cells appeared to be more sensitive to changes in serum concentration than were rheumatoid synovial cells, but rheumatoid synovial cells were more sensitive to changes in cell density. The proportion of newly synthesized extracellular proteoglycans increased with the duration of incubation in 35S--sulfate.
Assuntos
Artrite Reumatoide/metabolismo , Proteoglicanas/biossíntese , Membrana Sinovial/metabolismo , Adolescente , Adulto , Idoso , Contagem de Células , Células Cultivadas , Feminino , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Sulfatos/metabolismo , Membrana Sinovial/crescimento & desenvolvimentoRESUMO
Extracts containing uridine diphosphate (UDP) glucose dehydrogenase (EC 1.1.1.22) activity were prepared from rheumatoid and from normal human synovial cell lines using previously standardized techniques. Although no significant differences in the enzyme from the 2 sources were detected with respect to activity, substrate affinities, or responses to temperature and pH, these determinations have demonstrated that the enzyme is very sensitive to alterations in these parameters. The ultimate activity of the enzyme in vivo will be dependent upon the extent of the increased temperature, acidity, and altered glucose metabolism in the rheumatoid joint.
Assuntos
Artrite Reumatoide/enzimologia , Desidrogenases de Carboidrato/metabolismo , Membrana Sinovial/enzimologia , Uridina Difosfato Glucose Desidrogenase/metabolismo , Catálise , Células Cultivadas , Humanos , Concentração de Íons de Hidrogênio , Cinética , Membrana Sinovial/citologia , TemperaturaRESUMO
Extracts containing uridine diphosphate (UDP) glucose dehydrogenase (EC 1.1.1.22) activity were prepared from 5 normal human synovial cell lines and sources of variation in the method determined. The mean catalytic activity of UDP-glucose dehydrogenase from the 5 extracts was 12.0 +/- 2.4 x 10(-3) International Units/mg protein. The KmUDP-glucose was estimated as 3.90 +/- 1.56 x 10(-5) M and the KmNAD+ was estimated as 1.72 +/- 0.60 x 10(-4) M. Maximum catalytic activity occurred in a temperature range of 55 degrees C-68 degrees C and in a pH range of 8.1-8.4. The mechanistic implications of these data in the normal human diarthrodial joint are discussed.