The efficacy of CGS 20267 in suppressing estrogen biosynthesis in patients with advanced stage breast cancer

The pharmacologic inhibition of aromatase activity has been the focus of clinical trials in patients with advanced stage breast cancer. Recent developments with imidazole compounds that inhibit aromatase activity suggest their clinical use as potent inhibitors of estrogen biosynthesis in postmenopausal breast cancer patients. In this Phase I, open-label, dose-range finding study, we examined the inhibitory potency of CGS 20267 on blood and urine levels of estradiol, estrone and estrone sulfate in 8 patients with metastatic breast cancer. Studies included evaluation of adrenal and thyroid function to look for evidence of general hydroxylase inhibition at dose levels effective for aromatase blockade. Patients were administered CGS 20267 at doses of 0.1 and 0.25 mg, once a day in ascending doses over a 12-week period. Preliminary data reveal that CGS 20267 elicits a striking suppression in plasma estradiol, estrone and estrone sulphate which was observed in some patients as quickly as within 24 h of the first dose. Estrogen suppression of over 90% was achieved within 2 weeks of therapy. No alterations in either baseline or ACTH (cortrosyn) stimulated cortisol and aldosterone levels were observed through the 12 weeks of therapy. In addition, 24 h urine sodium and potassium values were not appreciably altered during therapy. We conclude that CGS 20267 is a potent, specific inhibitor of estrogen biosynthesis in postmenopausal patients with metastatic breast cancer and effectively reduces blood and urine estrogens to undetectable levels.     

Cyclooxygenase and 5-lipoxygenase inhibitory activity of 2,6 di-t-butylphenols linked by a sulfur atom to 1,3,4-thiadiazoles and 1,3,4-oxadiazoles

The preparation of a series of 1,3,4-thiadiazoles and 1,3,4-oxadizoles linked by a thioether to 2,6-di-t-butylphenol and the inhibition of cyclooxygenase (CO) and 5-lipoxygenase (5-LO) by these compounds is dicussed.     

Cyclitol production in transgenic tobacco

High levels of cyclic sugar alcohols (cyclitols) correlate with tolerance to osmotic stress in a number of plant species. A gene encoding a cyclitol biosynthesis enzyme from a halophyte, Mesembryanthemum crystallinum has been introduced into tobacco. The gene, lmt1 , encodes a myo -inositol O -methyl transferase that, in M. crystallinum , catalyzes the first step in the stress-induced accumulation of the cyclitol pinitol. Tobacco transformed with the lmt1 cDNA under the control of the CaMV 35S promoter appeared phenotypically normal and exhibited IMT1 enzyme activity. Transformants accumulated a carbohydrate product not detectable in non-transformed control plants. This product was identified by HPLC and NMR as ononitol (1- d -4- O -methyl myo -inositol). Ononitol was a major carbohydrate constituent in leaf tissue of plants expressing the lmt1 gene, accumulating to up to 25% the level of sucrose in transformant seedlings. The identification of ononitol as the IMT1 product and the specific accumulation of this compound in transformed tobacco support a role for ononitol as a stable intermediate in pinitol biosynthesis and indicate that an epimerization activity lacking in tobacco is responsible for the conversion of ononitol to pinitol in M. crystallinum . The production of ononitol in tobacco indicates that plant carbohydrate metabolism is flexible and can accommodate the synthesis and accumulation of non-endogenous metabolites. The transgenic system described here will serve as a useful model to test the ability of cyclitols such as ononitol to confer tolerance to environmental stress in a normally glycophytic plant.     

Establishment of fast-growing callus and root cultures of Cephalotaxus harringtonia

Summary Callus cultures were established from Cephalotaxus harringtonia (Japanese plumyew) stem expiants cultured on Murashige and Skoog medium supplemented with 4.5 M 2,4-dichlorophenoxyacetic acid and 0.05 M 6-furfurylaminopurine. The inclusion of 4.9 M 6-(,-dimethylallylamino) purine as the sole hormone significantly increased the growth rate of the callus. Organogenesis giving rise to both shoots and roots occurred upon transfer of the callus onto a hormonefree medium. Vitrification was common on all regenerated shoots cultured on Gelrite-containing medium. Regenerated roots were excised and established in McCown's woody plant medium. Doubling the phosphate and nitrate levels in the medium increased the growth of these root cultures.Abbreviations MS Murashige and Skoog basal medium - B5 Gamborg's B5 basal salt medium - WP McCown's woody plant basal salt medium - 2,4-D 2,4-dichlorophenoxyacetic acid - Kinetin 6-furfurylamino-purine - 2iP 6-(,-dimethylallylamino) purine - IBA indole-3-butyric acid     

Isolation and characterization of deteriosomes from rat liver

Deteriosomes, a new class of microvesicles, have been isolated from rat liver tissue. These microvesicles are similar to those isolated previously from plant tissue [Yao et al., Proc Natl Acad Sci USA 88:2269–2273, 1991] in that they are nonsedimentable and enriched in membrane catabolites, particularly products of phospholipid degradation. Liver deteriosomes range in size from 0.05 μm to 0.11 μm in radius. They are also much more permeable than microsomal membrane vesicles indicating that the deteriosome bilayer is perturbed. The data are consistent with the proposal that deteriosomes are formed from membranes by microvesiculation and that they represent an intermediate stage of membrane deterioration. Furthermore, liver deteriosomes were found to contain phospholipase A₂ activity. This suggests that they not only serve as a means of moving destabilizing macromolecular catabolites out of membranes into the cytosol but also possess enzymatic activity. The fact that the specific activity of phospholipase A₂ is higher in deteriosomes than in deteriosome-free cytosol suggests that some of the enzymatic activity traditionally assumed to be cytosolic may in fact be associated with deteriosomes.     

Medical direction and control of emergency medical services in Canada.

OBJECTIVE: To determine the level of physician involvement in prehospital emergency medical services (EMS) in Canada, as compared with published principles of medical control and direction. DESIGN: Mail and telephone survey by means of a questionnaire from March to November 1991. SETTING: All Canadian provinces and territories. PARTICIPANTS: Fifty-six key prehospital EMS physicians, senior government administrators and senior representatives of the agencies responsible for licensing physicians in each province or territory. MAIN OUTCOME MEASURES: Responses to questions regarding the legislation, organization, administration, practice and regulation of medical direction and control by physicians in each province or territory. RESULTS: EMS legislation describing medical direction and control was completely lacking in five provinces and both territories and was incomplete in the remainder. Provincial guidelines written by physicians for prehospital patient care were present in only four provinces. Formal organization of medical directors varied from none to partially remunerated networks. Regional medical-director systems were present in three provinces, and local medical directors were required for all communities in three. Most rural ambulance services were found to engage physicians only when there was local interest. CONCLUSIONS: The level of physician involvement in the medical direction and control of EMS appears to be inconsistent across Canada and insufficient in most jurisdictions, as compared with accepted principles.     

Dynamic genome-scale modeling of Saccharomyces cerevisiae unravels mechanisms for ester formation during alcoholic fermentation

Fermentation employing Saccharomyces cerevisiae has produced alcoholic beverages and bread for millennia. More recently, S. cerevisiae has been used to manufacture specific metabolites for the food, pharmaceutical, and cosmetic industries. Among the most important of these metabolites are compounds associated with desirable aromas and flavors, including higher alcohols and esters. Although the physiology of yeast has been well-studied, its metabolic modulation leading to aroma production in relevant industrial scenarios such as winemaking is still unclear. Here we ask what are the underlying metabolic mechanisms that explain the conserved and varying behavior of different yeasts regarding aroma formation under enological conditions? We employed dynamic flux balance analysis (dFBA) to answer this key question using the latest genome-scale metabolic model (GEM) of S. cerevisiae. The model revealed several conserved mechanisms among wine yeasts, for example, acetate ester formation is dependent on intracellular metabolic acetyl-CoA/CoA levels, and the formation of ethyl esters facilitates the removal of toxic fatty acids from cells using CoA. Species-specific mechanisms were also found, such as a preference for the shikimate pathway leading to more 2-phenylethanol production in the Opale strain as well as strain behavior varying notably during the carbohydrate accumulation phase and carbohydrate accumulation inducing redox restrictions during a later cell growth phase for strain Uvaferm. In conclusion, our new metabolic model of yeast under enological conditions revealed key metabolic mechanisms in wine yeasts, which will aid future research strategies to optimize their behavior in industrial settings.     

Molting fluid enzymes of the tobacco hornworm,Manduca sexta: Timing of proteolytic and chitinolytic activity in relation to pre-ecdysial development

Developmental profiles for a number of molting fluid (MF) enzyme activities were established and related to the progress of pupal cuticle degradation during the four days that precede the eclosion of adult tobacco hornworms. Cuticle degrading activity, molting fluid protease 1 (MFP-1), and molting fluid protease 2 (MFP-2) all increased in activity at the time that loss of material from the old cuticle occurred. In contrast, chitinase and β-acetylglucosaminidase activities did not parallel weight loss from the old cuticle. These results are consistent with the hypothesis that proteolytic activity is a prerequisite for the action of chitinase on cuticle chitin. © 1993 Wiley-Liss, Inc.