Diagnostic significance of connective tissue enzymes

In spite of the extensive literature, little is known of the diagnostic value of the enzymes of connective tissue metabolism. This review summarizes the available information and assesses the significance of enzyme measurements for the diagnosis of hereditary and nonhereditary connective tissue diseases, with emphasis being given to the roles of abnormal activities of collagenases and lysosomal glycosidases in the detection of fibrotic processes.     

Proteolytic activation of tissue plasminogen activator by plasma and tissue enzymes

Tissue kallikrein and factor Xa were found to activate tissue plasminogen activator (t-PA) at a rate comparable with that of plasmin. During the activation reaction, the single-chain molecule was converted into a two-chain form. A slight t-PA activating activity was also found in plasma kallikrein. Other activated coagulation factors, factor XIIa, factor XIa, factor IXa, factor VIIa, thrombin and activated protein C had no effect on t-PA activation. t-PA was also activated by a tissue kallikrein-like enzyme that was isolated from the culture medium of melanoma cells. These results indicate that tissue kallikrein and factor Xa may participate in the extrinsic pathway of human fibrinolysis.     

Electron transporting enzymes of rheumatoid connective tissue

The oxidative enzyme system of the synovial membrane and rheumatoid node from rheumatoid arthritic patients has been studied by histochemical and biochemical methods. As compared to the control synovial membranes, succinic dehydrogenase activity was substantially higher in the rheumatoid arthritic synovial membranes, and was still higher in the rheumatoid nodes, in which only the cells forming the palisade had succinic dehydrogenase activity. As compared to the controls, in response to menadione succinic dehydrogenase was significantly activated. The reducible ubiquinone content of the rheumatoid synovial membrane and the rheumatoid node was by several orders of magnitude higher than in the controls.     

Studies on bone enzymes. The assay of acid hydrolases and other enzymes in bone tissue.

1. Nine acid hydrolases, cytochrome oxidase, alkaline phenylphosphatase and catalase were demonstrated in 0.25m-sucrose homogenates of newborn-rat calvaria. The acid hydrolases were: acid phenylphosphatase, acid beta-glycerophosphatase, beta-glucuronidase, beta-N-acetylglucosaminidase (beta-N-acetylaminodeoxyglucosidase), acid ribonuclease and acid deoxyribonuclease, showing optimum activity at about pH5; cathepsin, beta-galactosidase and hyaluronidase, with optimum activity at about pH3.6. 2. The main kinetic characters of these enzymes have been studied and methods for their quantitative assay have been worked out. The activities present in bone are given and compared with those found in liver. 3. Acid-phosphatase activity was assayed with phenyl phosphate and beta-glycerophosphate as substrates: activities with these two substrates appeared to be due to two different enzymes. Acid phenylphosphatase is particularly labile and is readily inactivated by various physical or chemical agents.     

Effect of castration on male rabbit lower urinary tract tissue enzymes

Objectives The influence of testosterone on the prostate and corpus cavernosum have been studied extensively. However, the influence of testosterone on the lower urinary tract (bladder and urethra) have not been investigated to any great extent. The aim of this study was to determine whether androgen deprivation alters lower urinary tract metabolism. Methods A total of 16 rabbits were divided into four groups of four rabbits each. Each rabbit in groups 1–3 underwent surgical bilateral castration for duration of 1, 2 , and 4 weeks, and group 4 underwent sham operations. Sections of bladder body and base wall and mucosa, urethra and corpora were isolated, frozen, and stored under liquid nitrogen. The activities of citrate synthase-thapsigargin sensitive Ca²⁺ ATPase (Sarco/Endoplasmic Reticulum Ca²⁺ ATPase [SERCA]), and choline acetyl-transferase were examined as markers for mitochondrial function, sarcoplasmic reticular calcium storage and release, and cholinergic nerve function, respectively. Results The activity of SR function indicator, Ca²⁺ ATPase was significantly higher in the control corpora than in the control bladder or urethra. Castration resulted in decreased activity in the mitochondria specific enzyme, citrate synthase, the activity of which was greatest in the urethra and lowest in the corpora. Cholinergic nerve density indicator, choline acetyl-transferase activity was greatest in the bladder body and lowest in the urethra. Conclusions Our data indicate that (1) significant differences exist in the activities of all three enzymes in the various organs associated with the lower urinary tract; and (2) that castration results in significant alterations in the activities of all three enzymes in the bladder body, base, urethra, and corpora.     

Aldrin toxicity on amphibian neuronal, hepatic and muscular tissue oxidative enzymes

Aldrin toxicity was studied in the brain, liver and muscle of Rana hexadactyla. It was observed that sublethal concentration of aldrin inhibited the activities of SDH, MDH and ICDH while it elevated the activities of LDH and G-6-PDH. The increase and the decrease was progressive with the exposure period. The changes were attributed to the induced toxic effects such as oxygen distress, energy crisis and microstructural changes.