Antioxidant action of certain simple phenolic compounds derived from Chinese herbs

H2O2 and hydroxyl free radical active oxygen generation systems were utilized to define the antioxidant activities of simple phenolic compounds derived from Chinese herbs. Although the antioxidant activities of compounds differed when assessed in the two systems, all compounds tested were found to be effective at preventing red blood cell membrane lipid peroxidation, with the propyl and butyl esters of gallic acid being especially potent. No compound was able to prevent hemoglobin oxidation. All compounds but salicylic acid were found to interact dose-dependently with H2O2 and hydroxyl free radical as determined by a chemiluminescence method.

Physiological role of vitamin A in growth cartilage cells: low concentrations of retinoic acid strongly promote the proliferation of rabbit costal growth cartilage cells in culture

We have demonstrated that high concentrations of retinoic acid (RA) inhibit expression of the differentiated phenotypes of rabbit costal chondrocytes in culture [M. Takigawa et al. (1980) Proc. Natl. Acad. Sci. U.S. 77, 1481-1485]. In this study we examined the effects of low concentrations of RA on rabbit costal chondrocytes cultured in medium containing vitamin A-deficient serum. In vitamin A-deficient medium, chondrocytes isolated from growth cartilage (GC) proliferated only very slowly, and RA strongly stimulated their proliferation. This stimulatory effect was observable at a concentration of 10(-10) M RA and maximal at a concentration of 10(-8) M. RA at 10(-8) M did not change GC cells from a typical polygonal shape to fibroblast-like cells or inhibit their synthesis of type II collagen. Moreover, RA-treated cells did not synthesize type I collagen. RA inhibited glycosaminoglycan (GAG) synthesis by the cells dose-dependently, but did not change the distribution profile of proteoglycan monomers as determined by glycerol gradient centrifugation. The inhibitory action of RA on GAG synthesis was reversible: after removal of RA from the culture, the rate of GAG synthesis increased within 2 days. In contrast, resting cartilage (RC) cells proliferated well in vitamin A-deficient medium without addition of RA, and RA (10(-8) M) stimulated their proliferation only slightly. Furthermore, the inhibitory effect of RA on GAG synthesis in RC cells was much weaker than that in GC cells. These observations suggest a physiological role of RA in cartilage in stimulating the proliferation of GC cells without causing drastic change in their differentiated phenotypes.

[Radiotherapy of olfactory neuroblastoma--report of 5 patients]

Olfactory neuroblastoma is a rare tumor arising from the olfactory mucosal epithelium. 5 patients with this tumor were treated in our hospital from 1978 to 1982. The youngest patient was 3 years old and the eldest was 66. The clinical symptoms were nasal stuffiness, rhinorrhea, epistaxis and vascular polypoid mass in the nasal cavity. According to the staging system proposed by Kadish et al, the five patients in this series were 3 stage A and 2 stage C patients. Treatment consisted of radiotherapy, surgery or combination of radiotherapy and surgery. Our data indicate that the olfactory neuroblastoma is a radiosensitive tumor with the prognosis favorable in the stages A and B patients as treated by these three modalities. Two stage A patients are alive for more than 5 years. One of them was treated by radiotherapy alone, the other by combination of surgery and radiation. The third stage A patient as treated by radiotherapy alone has survived more than 3 years. One stage C patient, treated by combination of radiation and surgery, is still alive for more than 3 years. The other stage C patient, treated by radiotherapy alone, had survived for only 7 months after the treatment. The radiation dose varies with the extent of invasion. In stages A and B lesions, a dose of 4,500-5,500 rad in 5 weeks may be reasonable but in stage C, a dose of 6,000-6,500 rad in 7 weeks should be given. The authors agree to the prognostic equation proposed by Homzie et al. It may be possible to predict the tumor control or recurrence after a period of 3 years which gives an accuracy rate of 87%.

Purification and characterization of two forms of a low-affinity Ca2+-ATPase from erythrocyte membranes

A low-affinity Ca2+-ATPase from erythrocyte membranes has been purified by agarose suspension electrophoresis and polyacrylamide gel electrophoresis in the absence of detergents. For maximal activity a calcium concentration above 10 mM is required. The activity is independent of magnesium. The Km value for ATP is about 60 microM. The enzyme appears in two forms (A and B) with similar amino acid composition. The specific activity of A is higher than that of B. Gel electrophoresis in SDS of A gives a pattern consisting of two bands. B gives the same pattern; the only difference between the patterns is the ratio of the amounts of protein in the bands. The apparent molecular weight of the proteins in the two SDS bands has been estimated at 23000 and 21000, respectively. The results obtained can be explained by assuming that the two proteins corresponding to the two bands obtained in SDS electrophoresis have a similar structure and can associate to complexes A and B. We have also shown that electrophoretic and chromatographic supporting media can induce aggregation of (membrane) proteins. Artificial complexes can thus be formed and cause misinterpretation of the data obtained. This may be the reason why some authors have speculated that Ca2+-ATPase is active only in complex with other proteins such as spectrin and actin.