The growth of Rhodotorula rubra yeasts and their synthesis of ergosterol on media with lovastatin

The effect of lovastatin, a competing inhibitor of 3-hydroxy-3-methylglutaryl-CoA-reductase (HMG-CoA-reductase) of the fungal origin on the growth of and ergosterol biosynthesis by Rh. rubra VKPM Y 1337 was studied. It was shown that the yeast growth was inhibited by lovastatin in concentrations of 0.25 to 5.0 micrograms/ml when the inhibitor was added to the cultivation medium either with the inoculum or at later periods of the yeast cultivation. In concentrations of 2.0 to 5.0 micrograms/ml lovastatin almost completely inhibited the yeast growth. In the concentrations tested the inhibitor did not decrease the ergosterol level in the yeast cells below 40 per cent of the control. When lovastatin was added in concentrations of 1.0 to 5.0 micrograms/ml the maximum inhibition of the ergosterol biosynthesis was observed at the end of the growth log phase. Further cultivation of the yeast in the presence of the inhibitor resulted in an increase of the ergosterol biosynthesis. It is believed that the increase in the quantity of ergosterol may be due either to the HMG-CoA-reductase induction under the action of the inhibitor or to its inactivation as a result of the hydroxylation.     

The effect of early surgical excision and homografting on survival of burned rats and of intraperitoneally-infected burned rats

The effects of early and delayed surgical excision and skin homografting on survival in burned, uninfected rats and in burned rats infected with Pseudomonas aeruginosa, intraperitoneally, has been studied. The survival rate in animals treated with surgical excision and no coverage was significantly worse than in the animals who were simply burned. Immediate excision of the burn wound followed by prompt coverage with skin homografts resulted in decrease in the mortality rate from subsequent intraperitoneal infection of Pseudomonas. The beneficial effects of early surgical excisions and immediate skin homograft coverage were also achieved when formalin-fixed skin homografts were used.     

Should curative surgery be attempted in patients with cancer of the main stem bronchus?

Among tumors of the lung, main stem bronchial cancer offers a particularly unfavorable prognosis, probably because of its rapid extension to the segmental bronchi, trachea, and extrapulmonary structures. However, analysis of data gathered by the End Results Group indicates that survival among those patients with main stem bronchial cancer whose tumor was resected was virtually the same as that of patients with resectable lung cancer of other sites. From these data it is impossible to assess what role, if any, the resection itself played, and a randomized trial would be necessary to determine whether resection improves the probability of patient survival. On the other hand, it is not now advisable to deny resection to patients with operable main stem bronchial tumors (except oat cell tumors) on the basis of the available nonexperimental evidence alone.     

Optimization of the nutrient medium for Actinomyces spheroides--producer of proteolytic enzymes with fibrinolytic activity

Optimization of the medium for growing Actinomyces spheroides producing proteolytic exoenzymes with the fibrinolytic activity was performed by the method of mathematical planning. The composition of the medium is as follows (%): glucose 7.1, sodium citrate, trisubstituted, 0.48; (NH4)2SO4, 0.15; MgSO4, 0.575; KH2PO4, 0.2; ZnSO4, 0.001; FeSO4, 0.002. The fibrinolytic activity of the cultural broth on this medium is three times as high as on the initial medium (7142 units). Changes in the ratio between components of the medium lead to changes in the ratio between the fibrinolytic and caseinolytic activities. Therefore, Act. spheroides, strain 1, produces exoenzymes which differ by their substrate specificity. The ratio between the fibrinolytic and caseinolytic activities of the complex on the optimized medium is twice as high as on the initial medium.