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Taxomyces andreanae, a fungal endophyte, was isolated from the phloem (inner bark) of the Pacific yew, Taxus brevifolia. The fungus is hyphomyceteous and, when grown in a semi-synthetic liquid medium, produced taxol and related compounds. Taxol was identified by mass spectrometry, chromatography, and reactivity with monoclonal antibodies specific for taxol.(More)
Endophytic microbes associated with the Pacific yew tree, Taxus brevifolia, were examined as potential sources of the anticancer drug taxol [1], a secondary metabolite of the host organism. The first promising organism found was the novel fungus, Taxomyces andreanae, which was isolated from the inner bark of a yew tree growing in northwestern Montana. It(More)
Several diketopiperazines have been isolated from liquid cultures of Alternaria alternata, the causal agent of black leaf blight of spotted knapweed, Centaurea maculosa Lam. One of these compounds, maculosin [the diketopiperazine cyclo(-L-Pro-L-Tyr-)], was active in the nicked-leaf bioassay at 10(-5) M; synthetic maculosin possessed chemical and biological(More)
Alkoxy-aryl-lactams (cilostamide, AAL 05, ZK 62 711, Ro 20-1724) inhibit differently cAMP or cGMP phosphodiesterases from blood platelets or vascular smooth muscle. Cilostamide (IC50 0.23 microM) and AAL 05 (IC50 0.15 microM) are 100 times more potent towards platelet cAMP phosphodiesterase whereas ZK 62 711 (IC50 2 microM) and Ro 20-1724 (IC50 33 microM)(More)
Understanding the interaction between surfaces and their surroundings is crucial in many materials-science fields, such as catalysis, corrosion, and thin-film electronics, but existing characterization methods have not been capable of fully determining the structure of surfaces during dynamic processes, such as catalytic reactions, in a reasonable time(More)
Quercetin (3.3',4',5,7-pentahydroxyflavone) has previously been shown to inhibit cyclic nucleotide phosphodiesterases prepared from various cell homogenates and the function of intact human platelets. We now report that (1) high concentrations of quercetin raise platelet cAMP levels; and (2) quercetin potentiates the inhibitory effect of prostacyclin (PGI2)(More)
We describe a new variant of Glanzmann's thrombasthenia (variant Strasbourg I). The patient (M.S.) showed an absence of platelet aggregation to ADP, thrombin, and collagen, and a decreased clot retraction. Platelet fibrinogen was approximately 20% of normal levels. ADP-stimulated platelets bound markedly reduced amounts of soluble fibrinogen and platelet(More)
Amentoflavone hexaacetate (AmAc) was synthesized from natural amentoflavone (Am), a biflavonoid extracted from Viburnum lantana L. Am does not inhibit aggregation of intact platelets up to a concentration of 100 microM but inhibits human platelet cAMP phosphodiesterase (IC50 = 22.0 microM). AmAc is a potent inhibitor of the aggregation of washed human(More)
The presence of extracellular ionized calcium (Ca2+) is important to support the aggregation of human blood platelets and for the stability of the platelet fibrinogen receptor, the glycoprotein (GP) IIb-IIIa complex. This study was performed in order to determine the effects of intracellular calcium chelation on human platelet functions, on the expression(More)
Epinephrine can in certain in vitro conditions induce the aggregation of human platelets and could play an important role in vivo in the appearance of thrombotic disorders when catecholamine levels are increased. This study examines some functional and biochemical responses to epinephrine. Epinephrine induces the aggregation and serotonin secretion of human(More)