Alteration of transglutaminase activity in rat and human spinal cord after neuronal degeneration

We measured the activity of transglutaminase (TG), a Ca²⁺-dependent enzyme and a biochemical marker of cell degeneration, in the adult rat spinal cord after unilateral occlusion of a branch of the dorsal spinal artery, and compared it to the enzyme activity in the tissue on the contralateral side without ischemic damage. The affected half of the spinal cord showed a significant rise in intrinsic (endogenous) TG activity one day after ischemic insult while no apparent morphological changes were observed in the tissue. However, the enzymic activity on the affected side gradually decreased to reach the level in the non-affected tissue, accompanying severe degeneration of neuronal cells at 7 days after the surgery, then it declined to nearly half the level in the intact tissue 30 days after the operation. We also determined the TG activity in transverse sections of the human spinal cord obtained at autopsy from 5 amyotrophic lateral sclerosis (ALS) and 9 non-ALS patients. TG activity in thoracic and lumbar cords was markedly low in ALS patients not only in ventral and lateral regions but also in the dorsal portion. These findings imply that the reduced TG activity in the ALS spinal cord is one of the characteristic features of the disease reflecting exhaustion of the enzyme in the tissue resulting from degeneration of the spinal neurons through cross-linkage of soluble intraneuronal cytoplasmic proteins.     

Discovery of dicephalosterol, a new testosterone 5α-reductase inhibitor, and some new mycological aspects of its producer,Dicephalospora rufocornea (sclerotiniaceae, discomycetes)

Dicephalosterol, a new testosterone 5α-reductase inhibitor, was found from isolates ofDicephalospora rufocornea, a sclerotiniaceous discomycete widely distributed, but not previously cultured. Under SEM observation, the polar appendage of the ascospores inD. rufocornea was found to be more solid than was hitherto reported. Dicephalosterol was produced by submerged fermentation for 7 d. This new analogue of testosterone showed an IC₅₀ of 5.7 μg/ml for rat prostatic 5α-reductase, but no antimicrobial activity against bacteria or fungi.