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51.
Rodrigues C.R. Barreiro E.J. Romeiro N.C. Albuquerque M.G. De Sant'anna C.M.R. Bicca De Alencastro R. Da Motta Neto J.D. 《Molecular Engineering》1997,7(3-4):473-490
Two families of autacoids from cell membrane phospholipids have been identified. The first, the icosanoids, which are formed
from arachidonic acid, include prostaglandins and leukotrienes. The other includes modified phospholipids, as the platelet
aggregating factor (PAF). These compounds are related to inflammatory and cardiovascular diseases.
We review in this paper some of the work that has been done in our laboratories in the last few years relating to the modeling
of new potential thromboxane synthase (TXS) and 5-lipoxygenase (5-LO) and cyclooxygenase (COX) inhibitors, and TXA2 receptor antagonists derived from nitrogenated heterocycles. We include the results of the modeling of a group of proposed
PAF antagonists, and compare their structures with PAF itself and with a recently proposed PAF antagonist model.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
52.
The phytoplankton community of Lake Camaleão, a smallfloodplainlake influenced by a large whitewater river, the Solimões, was monthlyinvestigated for the composition and abundance of itsphytoplankton. The seasonal influence of the floodregime on biomass, species richness and diversity, andits relation with physical and chemical factors(temperature, pH, dissolved oxygen, electricalconductivity, total seston and inorganic nutrients)was analyzed and subjected to principal componentanalysis. Diversity was variable along the seasonalcycle: relatively high values were observed at the endof the dry season supported by high nutrientconcentrations. The phytoplankton was comprised of 262 taxa,with strong dominanceof euglenoids (81%). The three sample stations did not differamong each other, except in the dry season, due todata cluster in relation to theprincipal axis (1 and 2), explaining 63% of thevariation. Biomass accumulation as a function of lakearea reduction contributed to theseresults, indicating that the phytoplankton dynamicswere hydrology-driven. 相似文献
53.
T. Macedo C. A. Fontes Ribeiro D. Cotrim P. Tavares M. T. Morgadinho M. Caramona M. T. Nunes Vicente L. Rodrigues M. G. Cardoso M. L. Keating 《Molecular neurobiology》1995,11(1-3):21-29
This work evaluated in a population of heroin and heroin plus cocaine human addicts:
- Norepinephrine (NE), epinephrine (Epi), and 3-methoxy-4-hydroxyphenylglycol (MHPG) (the principal metabolite of brain NE) plasma levels;
- Monoamine oxidase (MAO) activity; and
- 3H-imipramine specific binding to the amine carrier in platelets.
54.
R A Prysor-Jones J J Silverlight J S Jenkins A N Stevens J L Rodrigues J R Griffiths 《FEBS letters》1984,177(1):71-75
Intravenous thyrotrophin releasing hormone (TRH) caused a 6.5-fold increase in plasma prolactin (PRL) in rats carrying implanted pituitary tumours. Vasoactive intestinal polypeptide (VIP) had no effect, but TRH given after VIP raised TRH stimulated secretion 13-fold above basal. 31P NMR spectroscopy showed that VIP caused a decrease in high energy metabolites (depleted phosphocreatine, elevated inorganic phosphate and lowered intracellular pH). TRH alone caused a similar but smaller effect; given after VIP, it caused no detectable depletion. We suggest that the changes in high energy metabolite concentrations reflect increased cellular energy consumption consistent with a priming process (stage 1) in PRL secretion, followed by hormone release (stage 2). VIP induces stage 1 whereas RTH induced both stages. 相似文献
55.
56.
L. Rodrigues de Miranda 《Antonie van Leeuwenhoek》1979,45(3):479-483
In Candida lusitaniae van Uden et do Carmo-Sousa (1959), strains of opposite sex have been found. Cells of the opposite mating types conjugate and form asci with one to four clavate spores. These are easily liberated from the ascus. The type strain of Candida obtusa (Dietrichson) van Uden et do Carmo-Sousa ex van Uden et Buckley (1970) also produces ascospores after mating with one of the strains of Candida lusitaniae. As clavate ascospores are unknow in yeasts, a new genus, Clavispora, is proposed with Clavispora lusitaniae spec. nov. as type species. 相似文献
57.
58.
The effects of an auxin herbicide, 2,4-D, at a concentration of 0.01 mM, on the K+ uptake and efflux of excised roots of wheat (Triticum aestivum L. cv. Rannaya) were investigated at different pH values. The K+ movement was monitored with a K+ (86Rb) tracer. In parallel experiments the ATPase activities of microsomal fractions were determined by the inorganic phosphate liberation method. 2,4-D inhibited the K+ uptake especially at low pH, irrespective of whether Ca2+ was present or not. No marked changes were observed in the K+ efflux properties at pH values above 4. The inhibitory effect on K+ uptake exhibited a correlation with the hydrocarbon solubility of the herbicide, but not with the 2,4-D-induced decrease of the ATPase activity. It is suggested that 2,4-D exerts a non-specific effect on the lipid-protein interactions, giving rise to a generalized alteration of the transport barrier properties of the plasma membrane even at as low a concentration as 0.01 mM. 相似文献
59.
60.
Studies were performed to determine the development of cell-mediated cytotoxic response at tumor site in C57BL/6 mice bearing progressively growing FBL-3 ascites leukemia. The effectors isolated from tumor ascites are found to be highly cytotoxic for leukemic target cells. The levels of cytotoxicity obtained with effectors isolated from tumor site are generally higher than those obtained with immune mice. This cytotoxicity is both specific and nonspecific. The specific cytotoxicity against tumor-associated antigen is mainly mediated by T cells and the nonspecific cytotoxicity against unrelated tumor cells is mediated largely by macrophages. The T-cell-enriched preparation did not give significant natural killer activity. When testing the ability of these effectors to produce in vivo immunity against the challenge of FBL-3, it was found that only T cells could confer the transplantation-type immunity, but the immunity was transient. The macrophage-enriched preparation isolated from tumor ascites failed to give in vivo protection. These findings indicate that in FBL-3 system, mice with progressively growing tumors are able to develop immune response against tumor cells. However, this immunity is probably interfered with by a suppressor factor(s) or suppressor cells which restrict their activity to eliminate the tumor cells effectively. 相似文献