In vivo
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Hyperactivition of an unwanted cellular cascade by the immune-related protein RNase L has been linked to reduced exercise capacity in persons with chronic fatigue syndrome (CFS). This investigation compares exercise capacities of CFS patients with deregulation of the RNase L pathway and CFS patients with normal regulation, while controlling for potentially confounding gender effects. Thirty-five male and seventy-one female CFS patients performed graded exercise tests to voluntary exhaustion. ⋯ A significant multivariate main effect was found for immune status (p < 0.01), with no gender effect or interaction. Follow-up analyses identified VO2(peak) as contributing most to the difference. These results implicate abnormal immune activity in the pathology of exercise intolerance in CFS and are consistent with a channelopathy involving oxidative stress and nitric oxide-related toxicity.
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The antitumor and antimetastatic activities of the plant cysteine endoproteinase bromelaine were evaluated in a murine model. Syngeneic sarcoma L-1 cells were incubated with bromelaine (after preceeding time and dosage kinetics) and subcutaneously; (s.c.) or intravenously; (i.v.) inoculated into BALB/c-mice (n = 5 per experimental group) to induce local tumor growth or lung colonization. Compared to non-protease incubated L-1 cells, local tumor growth and experimental lung metastasis decreased significantly (p < 0.05). ⋯ Intraperitoneal (i.p.) or s.c. administration of bromelaine (optimal dosage and time schedule tested in preceeding kinetic studies) significantly (p < 0.05) reduced local tumor weight, however, lung colonization was non-significantly reduced. Bromelaine incubation of sarcoma L-1 cells significantly reduced their tumorigenic/metastatic capacities. Bromelaine treatment after tumor cell inoculation significantly reduced local tumor growth, experimental lung metastasis, however, to a lesser, non-significant degree.