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81.
An extract from the parenchyma of Aloe barbadensis Miller shown to contain long chain polydispersed beta (1,4)-linked mannan polymers with random O-acetyl groups (acemannan, Carrisyn) was found to initiate the phagocyte production of monokines that supported antibody dependent cellular cytotoxicity and stimulated blastogenesis in thymocytes. Acemannan, in both enriched and highly purified forms, was administered intraperitoneally to female CFW mice into which murine sarcoma cells had been subcutaneously implanted. The rapidly growing, highly malignant and invasive sarcoma grew in 100% of implanted control animals, resulting in mortality in 20 to 46 days, dependent on the number of cells implanted. Approximately 40% of animals treated with acemannan at the time of tumor cell implantation (1.5 x 10(6) cells) survived. Tumors in acemannan-treated animals exhibited vascular congestion, edema, polymorphonuclear leukocyte infiltration, and central necrosing foci with hemorrhage and peripheral fibrosis. The data indicate that in vivo treatment of peritoneal macrophages stimulates the macrophage production of monokines, including interleukin-1 and tumor necrosis factor. The data further indicate that sarcomas in animals treated i.p. with acemannan at the time of tumor cell implantation were infiltrated by immune system cells, became necrotic, and regressed. The combined data suggest that acemannan-stimulated synthesis of monokines resulted in the initiation of immune attack, necrosis, and regression of implanted sarcomas in mice.  相似文献   
82.
1,9-Dideoxyforskolin inhibits proteoglycan synthesis and xyloside-initiated glycosaminoglycan (GAG) synthesis in chick embryo chondrocytes. Dideoxyforskolin does not affect the length of xyloside-initiated GAG chains secreted into the medium but chains from the dense proteoglycan secreted into the medium appear slightly longer. Incorporation of labeled serine into the dense proteoglycan and subsequent digestion with Pronase revealed a dramatic decrease in percent of total radioactivity associated with GAG chains in the proteoglyean from cultures treated with forskolin or dideoxyforskolin. These observations suggest that these diterpenes have a specific inhibitory effect on chain initiation reactions and thus may be useful tools in the study of proteoglycan synthesis and processing.  相似文献   
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The termini of the avian chick embryo lethal orphan (CELO) virus DNA have been sequenced. The results revealed a 63-bp-long inverted terminal repetition (ITR) which shared the sequence ATAATA with all adenovirus termini, thus far analyzed. The CELO virus ITR differed from those of the mammalian adenoviruses in two major aspects: (i) it is not a perfect duplication; (ii) it begins with a 5'-guanylic acid residue instead of the cytidylic acid normally observed in adenoviruses.  相似文献   
84.
Bisantrene and mitoxantrone are two new anthracene derivatives which have shown significant antitumor activity against a wide variety of animal tumors and in human phase I and II clinical trials. We have developed a rapid, simple and sensitive sample cleanup procedure and high-performance liquid chromatographic (HPLC) assay for both drugs. This method uses a commercially available mini-cartridge with C18 reversed-phase packing to isolate the drugs from the biological matrix prior to HPLC. For both drugs the average recovery of the assay was 98 ± 6% with a coefficient of variation (C.V.) of less than 7%. Using this new method our assay sensitivity has improved to less than 10 ng/ml for bisantrene and 1 ng/ml for mitoxantrone, allowing us to document a prologned terminal phase plasma half-life for both bisantrene and mitoxantrone. Equilibrium dialysis studies showed that both drugs are highly protein bound. Mitoxantrone appears less stable in human plasma than bisantrene. Recoveries from plasma after a 24-h incubation at 25 and 37°C were 40 and 20% for mitoxantrone and 90 and 85% for bisantrene, respectively. Addition of ascorbic acid prior to incubation of mitoxantrone in human plasma at 37°C resulted in less than a 10% decrease in the latter's concentration over a 24-h period. To maintain sample integrity, all plasma samples should be fortified with ascorbic acid and kept frozen prior to analyses.  相似文献   
85.
Little is known about the pathway of possible lymphocyte traffic in the nodules (germinal centers) of the node. Observations reported here indicate the involvement of the subnodular spaces. These spaces, which constitute the inner limit of the nodules, are contiguous to the perivascular channels of the postcapillary venules which partially encircle each nodule. Twelve hours after a local transfer of labeled thymic cells, they were observed in the subnodular spaces and in the perivascular channels of the draining nodes. It is proposed that the spaces and the channels provide a pathway for the rapid migration of lymphocytes entering a node via the afferent lymph and, probably, carrying an immunogenic information. The pathway would permit these cells to transmit the information rapidly to the appropriate cell population(s) of a node draining a tissue undergoing an immunological process.  相似文献   
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—Protein synthesis in an identified molluscan neurosecretory cell of the land snail, Otala lactea was examined using three different types of polyacrylamide gel electrophoresis. Cells taken from active snails synthesized specific low molecular weight proteins while those from aestivated snails did not. Most of the newly synthesized low molecular weight proteins in the active snails were lost from the cell body when the preparations was chased for 19 h in label-free enriched medium in the presence of anisomycin, an inhibitor of protein synthesis. If colchicine, a blocker of axonal transport, was included in the chase medium, the proteins present following a pulse were largely replaced by smaller molecular weight species. The results suggest that specific low molecular weight proteins are converted to smaller species and then transported from the cell body.  相似文献   
90.
国土空间生态修复国际经验借鉴与广东省实施路径   总被引:1,自引:0,他引:1  
李永洁  王鹏  肖荣波 《生态学报》2021,41(19):7637-7647
开展国土空间生态修复是生态文明和美丽中国建设的要求,是关系国家生态安全和民生福祉的重大国家战略任务。梳理了近100年来以荒野、再野化、基于自然的解决方案、生态修复为核心的国际生态环境治理理念的发展语境,辨析概念之间的关系,阐明国际生态修复基本研究框架,并梳理国外生态修复的典型实践案例,总结国际经验。基于对广东省主要生态问题研判,从摸清家底、确定目标、谋划格局、布置行动、实施保障5个层面构建省域国土空间生态修复科学规划总体框架,并以实际问题和生态修复目标为导向,提出深入开展国土空间生态修复规划九项专题研究、生态修复技术研发、多元组织形式等策略。本文提出的广东省生态修复设计思路及实施路径,将为找准生态环境问题根源、实现靶向修复治理、促进生态文明建设提供决策支持。  相似文献   
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