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1.
Optically active diastercoisomers of the brominated monoterpene quinols, cyclocymopol and cyclocymopol monomethyl ether, were isolated from the green marine alga Cymopolia barbata and charac- terized.  相似文献   
2.
Summary Marine allelochemicals generally are present in greater quantity and diversity in tropical than in temperate regions. Marine algal polyphenolics have been reported as an apparent exception to this biogeographic trend, with literature values for phenolic concentrations significantly higher in temperate than in tropical brown algae. In contrast, our results, the first reported for Caribbean brown algae (orders Dictyotales and Fucales), show that many species have high phenolic levels. In addition, both our study and previous studies with north temperate and tropical species demonstrate that there is marked variation in algal phenolic levels within species from different locations. We conclude that high phenolic concentrations occur in species from both temperate and tropical regions, indicating that latitude alone is not a reasonable predictor of plant phenolic concentrations.  相似文献   
3.
Trypanosoma musculi infections in CBA mice consist of a phase of increasing parasitemia during which dividing forms of the parasite are present in the blood, followed by a period when only nondividing trypomastigotes are seen. A second crisis terminates the blood infection and leaves the host immune, but small numbers of trypanosomes, including multiplicative forms, persist in the kidneys for many months. Studies were made involving infections in T-lymphocyte deprived mice, the effects of passive transfer of serum and cells, measurement of DNA synthesis by the parasite, serological responses, and in vitro effects of serum on the trypanosomes. These indicated that the initial check on the increase in blood parasitemia is due in part to two humoral factors. One of these has a trypanocidal effect (this is thought to be an IgM antibody) while the other, which may be an IgG antibody, is the ablastin that inhibits further reproduction by the parasite. Both trypanocidal and ablastic effects were demonstrable in the serum of immune mice yet the parasite was still able to survive and multiply in the kidneys.  相似文献   
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The Gates Malaria Partnership (GMP) includes five African and four European partner institutions. Its research programme has five priority areas involving an extensive range of field-based studies. GMP research has contributed significantly to the development of new research consortia investigating strategies for improving means of malaria control, and has already had an impact on policy and practice. A substantial investment in innovative training activities in malaria has enhanced knowledge and practice of malaria control at all levels from policy making to local community involvement. Capacity development, notably through a PhD programme, has been an underlying feature of all aspects of the programme.  相似文献   
6.

Background

Avoidance of allergens is still recommended as the first and best way to prevent allergic illnesses and their comorbid diseases. Despite a variety of attempts there has been very limited success in the area of environmental control of allergic disease. Our objective was to identify a non-invasive, non-pharmacological method to reduce indoor allergen loads in atopic persons' homes and public environments. We employed a novel in vivo approach to examine the possibility of using aluminum sulfate to control environmental allergens.

Methods

Fifty skin test reactive patients were simultaneously skin tested with conventional test materials and the actions of the protein/glycoprotein modifier, aluminum sulfate. Common allergens, dog, cat, dust mite, Alternaria, and cockroach were used in the study.

Results

Skin test reactivity was significantly reduced by the modifier aluminum sulfate. Our studies demonstrate that the effects of histamine were not affected by the presence of aluminum sulfate. In fact, skin test reactivity was reduced independent of whether aluminum sulfate was present in the allergen test material or removed prior to testing, indicating that the allergens had in some way been inactivated.

Conclusion

Aluminum sulfate was found to reduce the in vivo allergic reaction cascade induced by skin testing with common allergens. The exact mechanism is not clear but appears to involve the alteration of IgE-binding epitopes on the allergen. Our results indicate that it may be possible to diminish the allergenicity of an environment by application of the active agent aluminum sulfate, thus producing environmental control without complete removal of the allergen.  相似文献   
7.
Specific growth rate (G(S) ) and white skeletal muscle composition were measured in the mummichog Fundulus heteroclitus over a period of 28 days at four levels of dissolved oxygen (DO): severe hypoxia (c. 1.2 mg O(2) l(-1) ), moderate hypoxia (3.0 mg O(2) l(-1) ), normoxia (7.1 mg O(2) l(-1) ) and hyperoxia (10.6 mg O(2) l(-1) ). The G(S) was calculated over 0-8, 0-14, 0-28 and 14-28 days, and muscle protein, lactate dehydrogenase (LDH), DNA, RNA and water were measured at 0, 8, 14 and 28 days. Exposure of fish to severe hypoxia was associated with significantly reduced G(S) , lower muscle protein content and lower RNA:DNA compared with other DO treatments. When calculated over the first and second half of the 28 day exposure, however, G(S) of fish in severe hypoxia increased significantly during the second two-week interval, to the same rate as that of normoxic fish. Muscle LDH activity and water content were not significantly affected by DO level. Neither moderate hypoxia nor hyperoxia significantly affected G(S) or any biochemical variable. The results demonstrate that F. heteroclitus can tolerate wide variation in ambient oxygen concentration and, during prolonged exposure to severe hypoxia, shows significant compensation for the initial negative effects on growth. The capacity of F. heteroclitus to grow over a wide range of DO probably contributes to its ability to exploit habitats characterized by marked variation in oxygen availability.  相似文献   
8.
Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.  相似文献   
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10.
Both fisheries exploitation and increased nutrient loadings strongly affect fish and shellfish abundance and production in estuaries. These stressors do not act independently; instead, they jointly influence food webs, and each affects the sensitivity of species and ecosystems to the other. Nutrient enrichment and the habitat degradation it sometimes causes can affect sustainable yields of fisheries, and fisheries exploitation can affect the ability of estuarine systems to process nutrients. The total biomass of fisheries landings in estuaries and semi-enclosed seas tends to increase with nitrogen loadings in spite of hypoxia, but hypoxia and other negative effects of nutrient over-enrichment cause declines in individual species and in parts of systems most severely affected. More thoroughly integrated management of nutrients and fisheries will permit more effective management responses to systems affected by both stressors, including the application of fisheries regulations to rebuild stocks negatively affected by eutrophication. Reducing fishing mortality may lead to the recovery of depressed populations even when eutrophication contributes to population declines if actions are taken while the population retains sufficient reproductive potential. New advances in modeling, statistics, and technology promise to provide the information needed to improve the understanding and management of systems subject to both nutrient enrichment and fisheries exploitation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Guest editors: J. H. Andersen & D. J. Conley Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark  相似文献   
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