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51.
Lesa D. Fraker Susan A. Halter James T. Forbes 《Cancer immunology, immunotherapy : CII》1986,21(2):114-118
Summary Retinoids have been shown to inhibit the growth and development of neoplastic cells in many systems. One mechanism of action may be through activation of the immune system, specifically natural killer (NK) cell activity. The effect of retinol on NK cell cytotoxicity was examined in three groups of mice: BALB/c (wild-type), BALB/c nu/nu (athymic), and BALB/c nu/nu previously injected with human tumor cells. In untreated mice, NK activity was highest in athymic mice without tumors and lowest in wild-type mice, although serum and liver retinol concentrations were identical in all three groups. In mice fed graded, nontoxic doses of retinol daily for 3 weeks, serum retinol levels in all three groups exhibited a sharp peak and decline following daily bolus retinol administration. Retinol stores in the livers showed a dose-dependent increase in all treated animals. However, NK cell activity, differed for each group. Athymic mice without tumors exhibited no change in NK activity as a result of retinol treatment. Athymic mice with tumors had NK levels that tended to increase with increasing retinol doses, but these changes were not statistically significant. Wild-type mice, on the other hand, demonstrated significantly higher NK levels after treatment with retinol doses of 300 and 600 g/day. In subsequent time course experiments, there was a peak in NK activity 1 h following bolus retinol administration similar to the peak seen in serum retinol concentrations, suggesting either an acute activation or recruitment of cytotoxic cells. Retinol thus appears to increase NK activity in wild-type BALB/c mice, and this activity may be an important component of its antineoplastic activity.This investigation was supported by Biomedical Research Support Grant RRO 5424, the Veterans Administration, and PHS Grant number CA 33589-01A2, awarded by the National Cancer Institute, DHHSThis work was done in partial fulfillment of a Ph. D. thesis by L. Fraker in the Department of Pathology, Vanderbilt University School of Medicine 相似文献
52.
A low-interactive, captive, female lowland gorilla, Molly, was studied following the introduction into her enclosure of three gorillas, two males and a female, raised from birth in captive gorilla groups. Observations were made 6 mo after the new gorillas were introduced. Throughout the period of observation, Molly interacted in an affiliative manner with one of the males, playing or sitting quietly with him in a tree (where Molly spent most of her time) and occasionally on the ground. Agonistic displays between Molly and the new female decreased after they were released in the enclosure without the males for a series of days. Molly, however, continued to react to the other male, the most dominant, in an agonistic manner, and usually retreated from his reach, climbed the tree, and/or grimaced and piloerected whenever he approached. Although Molly's continued avoidance of the dominant male impeded her complete socialization, we propose that the interventions employed in this study—introduction of new younger gorillas into and an enclosure, and a series of dyadic separations between the noninteractive gorilla and each of the new group members—are possible strategies that can be used to facilitate socialization of captive, noninteractive gorillas. 相似文献
53.
Treatment of chicken embryo frbroblasts (CEF) with the tumor promoter, phorbol myristate accetate (PMA), resulted in a rapid increase in their ability to synthesize the glycosaminoglycan, hyaluronic acid (HA), whereas the parent compound, phorbol, had no effect. CEF cultures incubated with PMA (100 ng/ml) for 6 h resulted in a 15-fold increase in HA synthetase activity compared with phorbol-treated control cultures. The incorporation of [3H]acetate into HA and chemical determination of this polymer also demonstrated increased synthesis of HA by cells treated with PMA. We have previously shown that CEF infected with a temperature-sensitive mutant of Rous sarcoma virus, LA24, exhibit increased synthesis of HA upon transformation. PMA treatment of cells transformed with RSV-LA24 results in a further 1.5-fold stimulation of HA synthesis. These data indicate that PMA causes an increased synthesis of HA in CEF which is analogous to the increased synthesis of HA found in virally transformed CEF. 相似文献
54.
Helen M. Blau Cecelia Webster Choy-Pik Chiu Susan Guttman Frances Chandler 《Experimental cell research》1983,144(2):495-503
The interpretation of the majority of studies of Duchenne muscular dystrophy (DMD) has been complicated by the heterogeneous composition of the cultures used. In addition to muscle cells, muscle tissue contains adipocytes and fibroblasts and the proportion of these cell types varies, especially in disease states. To overcome this problem we developed culture conditions which permitted isolation and characterization of pure populations of clonally derived human muscle cells [1, 2]. Here we report the successful application of these methods to muscle cells from biopsies of individuals with diagnosed DMD. The normal and mutant human muscle cells were used in experiments of muscle differentiation in the same manner as cell lines. Frozen-stored cells were thawed, plated in a series of replicate plates, and allowed to differentiate under similar culture conditions. Yet, in contrast with cell lines, the cells were karyotypically normal, not altered by adaptation to long-term culture, and had a finite lifespan. We have systematically analysed specific properties of the normal and DMD muscle cells which differentiated in culture. The kinetics and extent of myoblast fusion, myotube morphology, and the accumulation and distribution of membrane acetylcholine receptors were monitored. In addition, the isozyme composition of creatine kinase and its intracellular and extracellular distribution were determined. Our results indicate that DMD muscle cells are fully capable of initiating myogenesis in culture and do not differ from normal muscle in several important parameters of differentiation. 相似文献
55.
Susan Y. Schmidt 《Journal of neurochemistry》1983,40(6):1630-1638
Light stimulation of isolated rat retinas is shown to enhance the turnover of phosphatidylinositol (PI) as demonstrated by a light-dependent increase in [3H]inositol incorporation and concurrent hydrolysis of existing PI. Studies with rat retinas incubated with [3H]inositol and then microdissected at the level of the outer plexiform layer into photoreceptor cell and inner retina layers indicated that the light-enhanced incorporation of [3H]inositol was associated with the photoreceptor cell layer. The rate of PI hydrolysis in retinas prelabeled in vivo with [3H]inositol was higher in light than in dark incubations and was higher in the photoreceptor cell layer than within the inner retina. Within the photoreceptor cell layer, PI turnover involved 2%/min of the total PI contentin dark and 6–8%/min in light. In contrast to what has been reported for stimulus-enhanced turnover of PI in some tissues, this light-enhanced turnover of PI in the retina was not associated with detectable reductions in PI content. Parallel studies of sodium (22Na) uptake demonstrated that the photoreceptor cells remained functional during these incubations as they retained the capacity to restrict the entry of 22Na in light but not in dark. 相似文献
56.
Corpora allata from Diploptera punctata females at adult ecdysis or at the end of the last-larval stadium, when implanted into decapitated females, underwent a cycle of juvenile hormone synthesis similar in timing and magnitude to that of glands implanted into control animals which had been starved and allatectomized. Starvation did not alter the cycle in rates of juvenile hormone synthesis of sham-operated animals.Decapitation of ovariectomized animals resulted in no cycle in rates of juvenile hormone synthesis by implanted adult corpora allata; however, implantation of an ovary along with the corpora allata into decapitated, ovariectomized hosts resulted in a cycle of juvenile hormone synthesis. In control animals, which retained their heads but were starved and allatectomized as well as ovariectomized, the implanted corpora allata showed a cycle of juvenile hormone synthesis only when implanted with an ovary. The maximal rates of juvenile hormone synthesis by the corpora allata in both experimental and control conditions were lower than normal, likely due to the repeated trauma of surgery. However, at no time from eclosion to the end of the first gonotrophic period was the brain necessary for the cyclic response of the corpora allata to the presence of the ovary. 相似文献
57.
Studies on the lipid composition of the rat liver endoplasmic reticulum after induction with phenobarbitone and 20-methylcholanthrene 总被引:4,自引:4,他引:0
1. The cholesterol content, proportions of different phospholipids and fatty acid components of phosphatidylcholine and phosphatidylethanolamine were studied in rat liver endoplasmic-reticulum membrane, after a single injection of 20-methylcholanthrene or injections of phenobarbitone for 5 days. 2. A marked decrease in the proportion of cholesterol occurred 5 days after injection of 20-methylcholanthrene or phenobarbitone. 3. The proportion of phosphatidylcholine was increased by injection of phenobarbitone and minor changes occurred in other phospholipids. 4. Phenobarbitone caused the proportion of linoleic acid in phosphatidylcholine and phosphatidylethanolamine to increase to 120-125% of the control and the proportion of oleic acid, arachidonic acid and docosahexaenoic acid to decrease. 5. 20-Methylcholanthrene caused an increase in the proportion of oleic acid in phosphatidylcholine and ethanolamine to 125-140% of the control, 1 day after injection. 6. The increased proportion of linoleic acid in phosphatidylcholine after phenobarbitone injection occurs simultaneously with the increase of cytochrome P-450 concentration, the rate of oxidative demethylation of aminopyrine and the rate of hydroxylation of biphenyl. It is therefore considered that distinct species of phosphatidylcholine or phosphatidylethanolamine containing linoleic acid in the beta position are essential in the endoplasmic-reticulum membrane for optimal activity of oxidative demethylation. 相似文献
58.
59.
Specificity of the Induced Bactericidin of the West Indian Spiny Lobster, Panulirus argus 总被引:3,自引:0,他引:3 下载免费PDF全文
Peter F. Weinheimer Ronald T. Acton Susan Sawyer E. Edward Evans 《Journal of bacteriology》1969,98(3):947-948
To investigate the specificity of an inducible hemolymph bactericidin, West Indian spiny lobsters were immunized with a variety of antigens. Bactericidal assays were conducted with strain EMB-1, a gram-negative bacillus isolated from normal lobster intestine. Animals given saline solution with or without 0.3% Formalin exhibited only a slight response similar to sham controls. Injections of type 2 pneumococci or bovine albumin produced slightly higher responses. These were much less pronounced than the homologous response to EMB-1. Formalin exhibited an adjuvant-like effect with EMB-1. 相似文献
60.