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81.
Isolation and characterization of natural products from plant tissue cultures of Maytenus buchananii
James P. Kutney Michael H. Beale Phillip J. Salisbury Kenneth L. Stuart Brian R. Worth Phillip M. Townsley William T. Chalmers Kristina Nilsson Giullo G. Jacoli 《Phytochemistry》1981,20(4):653-657
Explants of Maytenus buchananii were induced to form a callus aid subsequently to form suspension cultures on a wide variety of media. Culture extracts showed cytotoxic activity, but examination by TLC did not indicate the presence of maytansine. Isolation of natural products from a large scale suspension culture led to the identification of polpunonic acid, sitosterol and the cytotoxic triterpene quinone-methides, tingenone and 22β-hydroxytingenone. Possible biosynthetic relationships of these and other triterpene quinone-methides are discussed. 相似文献
82.
G J Rowse R E Rowan A J Worth P E Reid J Weinberg J T Emerman 《Histology and histopathology》1990,5(4):485-491
We have previously demonstrated that growth rate and morphology differ between androgen-responsive Shionogi mouse mammary tumours maintained in male and female mice. Furthermore, we can modulate the growth rate of these tumours in male mice by exposing the mice to psychosocial stressors. In the present study, we were interested in determining if tumours in male mice with a comparable growth rate to that in females, also had a morphology similar to that in females. SC115 tumours were examined using histochemical and immunohistochemical techniques. Tumours in male mice were easily distinguishable from tumours in female mice regardless of growth rate. Tumours maintained in female mice contained osteoid-like regions which stained positive for sialic acid and sulphate moieties. No such regions were observed in any of the tumours from male mice. In addition, although all tumours contained MSA (muscle specific actin)-positive and S100 protein-positive cells, these regions were more extensive in the tumours of female mice. This study suggests that tumour growth rate and morphology are independently regulated by the host environment. 相似文献
83.
84.
Inhibition of human lymphocyte rosetting by anti-T sera 总被引:14,自引:0,他引:14
85.
Summary This study demonstrates that phenotypic characteristics of androgen-responsive (AR) Shionogi mouse mammary tumors and androgen-independent
(AI) derivatives can be maintained in culture. Cells were seeded onto collagen gels in medium containing 2% dextran-characoal-treated
fetal bovine serum with or without 0.01 μg/ml dihydrotestosterone (DHT). Androgen-responsive tumors grew more rapidly than
AI tumors in vivo and consequently, cells from AR tumors cultured in DHT-containing medium grew faster than cells in DHT-deprived
medium and cells from AI tumors. Androgen-responsive tumors had a sheetlike growth pattern; AI tumors formed clumps or irregular
cords of cells. Cells from AR tumors cultured in the presence of DHT formed confluent pavements, whereas cells maintained
in the absence of DHT and cells from AI tumors formed clusters or cords of cells. Ultrastructurally, cells of AR tumors were
elongated; cells of AI tumors were smaller and rounder. These cellular morphologies persisted in culture. Tumorigenicity of
cells was assayed by injecting cells s.c. into host mice. Tumors arising from cells of freshly dissociated AR tumors and cells
of AR tumors cultured in the presence of DHT appeared more rapidly and grew faster in intact males than in castrated males
and intact females. Tumors arising from cells cultured in the absence of DHT and from freshly dissociated or cultured cells
of AI tumors had identical rates of appearance and growth in all hosts. This culture system permits these cells to retain
their state of malignant progression in vitro and should be a useful model for studying the origin of heterogeneity within
tumors and its role in tumor behavior.
This work was supported by a grant from the National Cancer Institute of Canada. J. T. E. is a Research Scholar of the National
Cancer Institute of Canada. 相似文献
86.
Paul M. King Christopher A. Reynolds Jonathan W. Essex Graham A. Worth W. Graham Richards 《Molecular simulation》2013,39(5):265-275
When determining the biochemical function of a proposed new drug it is useful to be able to calculate a number of properties which regulate its behaviour. By using the Free Energy Perturbation method incorporated into molecular dynamics, both on its own and in conjunction with quantum mechanical calculations, we have calculated redox potentials, pKa s, tautomer ratios and partition coefficients on model systems. This paper reviews the techniques currently being used to perform such calculations and presents the results for a number of different systems. The accuracy with which the properties are determined is most encouraging and suggests that useful calculations on realistic systems are now possible, and will play a major role in drug-design in the future. 相似文献
87.
James P. Kutney Lewis S.L. Choi Pawel Kolodziejczyk Stephen K. Sleigh Kenneth L. Stuart Brian R. Worth W.G.W. Kurz K.B. Chatson F. Constabel 《Phytochemistry》1980,19(12):2589-2595
A detailed study of one cell line (coded as 943) of Catharanthus roseus cell cultures has revealed the presence of the following alkaloids: ajmalicine, vallesiachotamine, hörhammerinine, hörhammericine, vindolinine, 19-epi- vindolinine, 19-acetoxy-11-methoxytabersonine, 19-acetoxy-11 -hydroxytabersonine, 19-hydroxy- 11-methoxytabersonine, yohimbine and isositsirikine, together with dimethyltryptamine and a new strychnos-type alkaloid. 相似文献
88.
Shawn P. Ryan Sang Don Lee M. Worth Calfee Joseph P. Wood Stella McDonald Matt Clayton Nicole Griffin-Gatchalian Abderrahmane Touati Luther Smith Melissa Nysewander 《World journal of microbiology & biotechnology》2014,30(10):2609-2623
Decontamination studies investigating the effectiveness of products and processes for the inactivation of Bacillus species spores have traditionally utilized metering viable spores in a liquid suspension onto test materials (coupons). The current study addresses the representativeness of studies using this type of inoculation method compared to when coupons are dosed with a metered amount of aerosolized spores. The understanding of this comparability is important in order to assess the representativeness of such laboratory-based testing when deciding upon decontamination options for use against Bacillus anthracis spores. Temporal inactivation of B. anthracis surrogate (B. subtilis) spores on representative materials using fumigation with chlorine dioxide, spraying of a pH-adjusted bleach solution, or immersion in the solution was investigated as a function of inoculation method (liquid suspension or aerosol dosing). Results indicated that effectiveness, measured as log reduction, was statistically significantly lower when liquid inoculation was used for some material and decontaminant combinations. Differences were mostly noted for the materials observed to be more difficult to decontaminate (i.e., wood and carpet). Significant differences in measured effectiveness were also noted to be a function of the pH-adjusted bleach application method used in the testing (spray or immersion). Based upon this work and the cited literature, it is clear that inoculation method, decontaminant application method, and handling of non-detects (i.e., or detection limits) can have an impact on the sporicidal efficacy measurements. 相似文献
89.
Previous in vitro models of the airways are either rigid or, if flexible, have not matched in vivo compliance characteristics. Rapid prototyping provides a quickly evolving approach that can be used to directly produce in vitro airway models using either rigid or flexible polymers. The objective of this study was to use rapid prototyping to directly produce a flexible hollow model that matches the biomechanical compliance of the trachea. The airway model consisted of a previously developed characteristic mouth–throat region, the trachea, and a portion of the main bronchi. Compliance of the tracheal region was known from a previous in vivo imaging study that reported cross-sectional areas over a range of internal pressures. The compliance of the tracheal region was matched to the in vivo data for a specific flexible resin by iteratively selecting the thicknesses and other dimensions of tracheal wall components. Seven iterative models were produced and illustrated highly non-linear expansion consisting of initial rapid size increase, a transition region, and continued slower size increase as pressure was increased. Thickness of the esophageal interface membrane and initial trachea indention were identified as key parameters with the final model correctly predicting all phases of expansion within a value of 5% of the in vivo data. Applications of the current biomechanical model are related to endotracheal intubation and include determination of effective mucus suctioning and evaluation of cuff sealing with respect to gases and secretions. 相似文献
90.