Brian S. Middleditch

Bioflavonoid interaction with rat uterine type ii binding sites and cell growth inhibition

Competition analysis with a number of known bioflavonoids demonstrated that these compounds (luteolin, quercetin, pelargonin) compete for [3H]estradiol binding to cytosol and nuclear type II sites in rat uterine preparations. The inhibition of [3H]estradiol binding to type II sites was specific and these bioflavonoids did not interact with the rat uterine estrogen receptor. Since estradiol stimulation of nuclear type II sites in the rat uterus is highly correlated with cellular hypertrophy and hyperplasia, we assessed the effects of these compounds on the growth of MCF-7 human breast cancer cells in culture and on estradiol stimulation of uterine growth in the immature rat. The data demonstrated that addition of quercetin (5-10 micrograms/ml) to MCF-7 cell cultures resulted in a dose-dependent inhibition of cell growth (DNA/flask). This effect was reversible by removal of quercetin from the culture medium, or by the addition of 10 nM estradiol-17 beta to these cell cultures containing this bioflavonoid. Since estradiol-17 beta (10 nM) stimulated nuclear type II sites and proliferation of MCF-7 cells, we believe bioflavonoid inhibition of MCF-7 cell growth may be mediated through an interaction with nuclear type II sites. This hypothesis was confirmed by in vivo studies which demonstrated that injection of luteolin or quercetin blocked estradiol stimulation of nuclear type II sites in the immature rat uterus and this correlated with an inhibition of uterine growth (wet and dry weight). These studies suggest bioflavonoids, through an interaction with type II sites, may be involved in cell growth regulation.

Metabolic profiles of penaeid shrimp: dietary lipids and ovarian maturation.

The major impediment to the culture of penaeid shrimp in captivity in the United States has been an inability to obtain ovarian maturation and spawning. Lipid profiles of tissues (gonads, hepatopancreas, and tail muscle) of Penaeus setiferus caught at sea have shown that cholesterol is the dominant sterol and that polyunsaturated fatty acids known to be essential in man comprise a significant portion of the fatty acid fraction. A prioprietary marine ration contains cholesterol, but is devoid of polyunsaturated fatty acids. Ovarian maturation and spawning were obtained when the shrimp diet was supplemented with an annelid rich in lipids containing these compounds. The biochemical significance of these findings is discussed.

Polycyclic aromatic hydrocarbons in the Murchison meteorite

Abstract More than thirty polycyclic aromatic hydrocarbons, including nine heterocyclic aromatic compounds, have been identified in solvent extracts of the Murchison meteorite by gas chromatography-mass spectrometry using bonded-phase fused silica columns. Structural isomers of several alkylated aromatic hydrocarbons, including methylpyrene and methylphenanthrene were chromatographically separated, thus allowing calculations of the amount of alkyl substituted compounds in the solvent extracts. The ratio of odd-carbon number to even-carbon number was found to be approximately 0.1. Based on these data and literature data from model pyrolysis experiments, a temperature of 1000°C is suggested for the formation of polycyclic aromatic hydrocarbons in the solar nebula or premeteoritic body. The value of 1000°C is within the range of temperatures for the condensation of the nebular material from the initial high temperature phases to the lower temperature phases at which chemical and isotopic equilibria were frozen. A simple model for the abiotic synthesis of heterocyclic compounds from simple aliphatic precursors is also presented.

Simultaneous gas chromatography of volatile and non-volatile carboxylic acids as tert.-Butyldimethylsilyl derivatives

Abstract Solid phase extraction with subsequent ion pair formation and silylation was investigated for the simultaneous trace enrichment of volatile and non-volatile carboxylic acids from complex aqueous samples. The solid phase extraction of acids was performed using Chromosorb P as the solid sorbent. The ether eluate was treated with triethylamine. The resulting triethylammonium salts of the acids were converted to stable tert.-butyldimethylsilyl (TBDMS) derivatives, which were analyzed by gas chromatography (GC) and GC-mass spectrometry. The characteristic M - 57 ions in the mass spectra of TBDMS derivatives enabled rapid identification of acids. The application of the method to the organic acid profiling of urine and saliva samples is demonstrated.

Lipids of contemporary stillingia oil

SummaryContemporary stillingia oil from China is qualitatively similar to the oil described earlier, but it exhibits significant quantitative differences reflecting a degree of autoxidation of the unsaturated fatty acids either before or after crushing of the seeds.

Gas chromatographic—mass spectrometric analysis of volatile constituents in saliva

Present methods for the development of metabolic profiles are limited to the use of headspace techniques and solvent extraction methods. A new method for the development of saliva profiles which provides information complementary to existing analyses has been developed. The results of the developed methodology provide a reliable, reproducible method for metabolic profiling. Gas chromatographic-mass spectrometric analysis of the volatile constituents provided positive identification of 39 compounds. Application of the developed protocol toward the investigation of saliva as a vehicle for the non-invasive detection of certain pathological states, specifically diabetes mellitus and liver disorders, may be possible.

Ecological effects of produced water effluents from offshore oil and gas production platforms

Abstract The literature pertaining to the composition of produced waters and the fates and effects of these effluents in the marine environment has been reviewed. Discussions of lethal and sublethal effects have been complemented by considerations of data relating to crude oils, petroleum products, and individual constituents. Two distinct strategies have been employed in attempts at discerning the ecological effects of produced water effluents: predictive and observational. The predictive approach involves determining the composition of the effluents and considering the toxicities of individual components in an attempt to deduce the overall toxicity of the effluent. The observational approach, although site-specific, provides direct and unequivocal information relating to ‘real-world’ effects. By combining both the predictive approach and the observational approach, it can be concluded with a high degree of confidence that current practises for the disposal of produced waters are ecologically sound.

Trace analysis of volatile polar organics by direct aqueous injection gas chromatography

SummaryProcedures for the quantitative analysis of industrial effluents which involve concentration by solvent extraction or the purge-and-trap method are time-consuming, labor-intensive, and prone to error. Direct aqueous injection gas chromatography using an electron-capture detector for the analysis of volatile halocarbons at the ppb level is in routine use in many laboratories. We now discuss the development of a similar protocol for the analysis of volatile polar organics such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and tretrahydrofuran using a flame-ionization detector.

Mass spectrometry of priority pollutants

This book presents information on the following subjects: anintroduction to gas chromatography; mass spectrometry; review of available methods for comparing spectra; selective ion monitoring; problems associated with the analysis of volatile samples and problems of data processing; use of mass spectrometry in environmental science, cosmo-chemistry, geochemistry, and the pharmaceutical and petrochemical industries; and modern mass spectrometers.

Estrogen regulation of methyl p-hydroxyphenyllactate hydrolysis: correlation with estrogen stimulation of rat uterine growth.

We have recently demonstrated that methyl p-hydroxyphenyllactate (MeHPLA) is the endogenous ligand for nuclear type II binding sites in the rat uterus and other estrogen target and non-target tissues. MeHPLA binds to nuclear type II binding sites with a very high binding affinity (Kd approximately 4-5 nM), blocks uterine growth in vivo, and inhibits MCF-7 human breast cancer cell growth in vitro. Conversely, the free acid (p-hydroxyphenyllactic acid, HPLA) interacts with type II binding sites with a much lower affinity (Kd approximately 200 nM) and does not inhibit estrogen-induced uterine growth in vivo or MCF-7 cell growth in vitro. On the basis of these observations, we suggested that one way that estrogen may override MeHPLA inhibition of rat uterine growth may be to stimulate esterase hydrolysis of MeHPLA to HPLA. The present studies demonstrate that the rat uterus does contain an esterase (mol. wt approximately 50,000) which cleaves MeHPLA to HPLA, and that this enzyme is under estrogen regulation. This conclusion is supported by the observations that MeHPLA esterase activity is increased 2-3-fold above controls within 2-4 h following a single injection of estradiol, and is maintained at high levels for 16-24 h following hormone administration. This sustained elevation of MeHPLA esterase activity correlates with estradiol stimulation of true uterine growth and DNA synthesis.