Scott E. Taylor

Liquid fuels fromMesua ferrea L. seed oil

Mesua ferrea L. seed oil consists of triglycerides of linoleic, oleic, palmitic and stearic acids. These acids were pyrolyzed separately in the presence of different amounts of solid sodium carbonate. Pyrolysis experiments revealed that linoleic and oleic acids can be converted to hydrocarbons of a wide range of molecular weights by pyrolyzing them with even 1% by wt of sodium carbonate up to a temperature of 500°C, whereas palmitic and stearic acids can be converted to hydrocarbons only by pyrolyzing them with equivalent amounts or more of sodium carbonate up to a temperature of about 650°C.The fractions of boiling range 60–320°C of all of the pyrolytic oils were analyzed for their hydrocarbon types by the method of fluorescent indicator adsorption (FIA). The aromatic contents of the pyrolytic oils of linoleic and oleic acids were found to be much higher than those of palmitic and stearic acids. GS and GC-MS analyses of all the saturate fractions indicated mainly normal alkanes with a carbon number range of 6 to 17.

Binding Potency of Paroxetine Analogues for the 5-Hydroxytryptamine Uptake Complex*

Abstract— The in‐vitro inhibition constants (Ki) of 14 structural analogues of the potent 5‐hydroxytryptamine (5‐HT)‐uptake inhibitor paroxetine were determined to assess the structure‐affinity relationship of these derivatives. A goal of these studies was to determine those positions on paroxetine which could be derivatized without significantly decreasing the affinity of the drug for the binding site, so that radiolabels such as [18F]fluoroalkyl groups might be appended for future in‐vivo imaging studies of the 5‐HT uptake system. Using the methyl moiety as a steric probe for these studies, it was found that the rank order of potency of various methyl‐substituted paroxetine analogues for inhibiting the binding of [3H]paroxetine to the 5‐HT re‐uptake site was: 4′≅ 3′‐≅ 2″‐>2′‐≅ 1‐ >5″‐> 6″‐methyl. The in‐vitro equipotent molar ratios (EPMR, Ki(analogue)/Ki(paroxetine)) of the analogues were determined, and the EPMRs of the 4′‐,3′‐, and 2″‐methyl derivatives were 1·9, 2·2 and 2·2, respectively. The 4′‐ and 2″‐fluoromethyl and ‐fluoroethyl analogues were synthesized, and the EPMRs of the 4′‐ and 2″‐fluoromethyl derivatives were determined to be 2·0 and 3·5, and those of the 4′‐ and 2″‐ fluoroethyl analogues were 5·2 and 6·2, respectively. The 2″‐fluoromethyl analogue was unstable in aqueous solutions, and it is not a promising ligand for in‐vivo studies. The 4′‐fluoromethyl derivative was stable in aqueous solutions and, based upon its relatively high affinity, is a candidate for radiolabelling with 18F for in‐vivo positron emission tomography studies of the 5‐HT re‐uptake site.

Variation in photosynthetic electron transport capacity in vivo and its effects on the light modulation of ribulose bisphosphate carboxylase

Photosynthetic electron transport capacity was varied in vivo in sugar beets using iron deficiency, and its effects on the light modulation of ribulose bisphosphate carboxylase (RuBPCase) studied. Three treatment groups corresponding to decreasing amounts of thylakoids per leaf area were examined: iron sufficient (control), moderately iron-stressed, and severely iron-stressed. Reduction in electron transport capacity in vivo was correlated with a substantial decrease in the level of RuBPCase activation, even at saturating irradiances. These results indicate a direct relationship between RuBPCase activation and photosynthetic electron transport. In addition, our data suggest that the activation of RuBPCase could not solely account for the increases in the photosynthetic rate at high irradiances; RuBPCase reached maximal activation at irradiances well below light saturation for net photosynthesis.

Binding potency of 6-nitroquipazine analogues for the 5-hydroxytryptamine reuptake complex

Abstract— The in‐vitro inhibition constants (Ki) of nine structural analogues of the potent 5‐hydroxytryptamine (5‐HT)‐uptake inhibitor, 6‐nitroquipazine, were determined to assess the structure‐affinity relationship of these derivatives. The goal of these studies was to determine those positions on 6‐nitroquipazine that could be derivatized without significantly decreasing the affinity of the drug for the binding site, so that radiolabels such as 123I, 76Br or 18F might be appended for in‐vivo imaging studies of the 5‐HT reuptake system. Using bromine as a steric probe, the rank order of potency of bromine‐substituted 6‐nitroquipazine analogues for inhibiting the binding of [3H]paroxetine to the 5‐HT reuptake binding site was: 8‐<3‐<7‐<4‐<5‐bromo. The in‐vitro equipotent molar ratio (EPMR, Ki (analogue)/Ki(6‐nitroquipazine)) of the 5‐bromo analogue was 0·57, indicating that this analogue had greater affinity for the 5‐HT reuptake complex than 6‐nitroquipazine. Derivatization at the 5‐position with fluorine and iodine also resulted in potent compounds with EPMR values of 1·1 and 0·83, respectively. Substitution of quipazine with bromo, cyano, and formyl groups at the 6‐position produced less potent compounds than the 6‐nitro group. Based upon the high affinities of the 5‐bromo‐, 5‐fluoro‐ and 5‐iodo‐6‐nitroquipazines for the 5‐HT reuptake complex, these compounds are candidates for radiolabelling for in‐vivo studies of the 5‐HT reuptake site.

No effect of age and estrogen on aromatic L- amino acid decarboxylase activity in rhesus monkey brain.

A variety of studies have shown an effect of estrogen on dopamine function and suggest that estrogen may modulate central dopaminergic activity. Positron emission tomography (PET) and the dopamine metabolism tracer, [18F]6-fluoro-L-m-tyrosine (FMT) were used to evaluate dopaminergic function in the frontal cortex and striatum in six aged, but pre-menopausal, female monkeys before and after ovariectomy (OVX). Dynamic PET brain uptake data and metabolite-corrected blood input functions were fit to a three-compartment model for FMT uptake. Prior to OVX, all animals showed preferential accumulation of the tracer bilaterally in the striatum and less but measurable activity in the frontal cortex. Paired comparisons showed that there were no significant differences in FMT uptake (K(i)) in either brain region before and after OVX. In addition, FMT uptake did not differ from a group of young adult female monkeys at either time point. These findings may represent a compensatory up-regulation of aromatic L- amino acid decarboxylase (AADC) activity.

Estimating glucose metabolism using glucose analogs and two tracer kinetic models in isolated rabbit heart

The purpose of this investigation was to 1) evaluate the relative accuracy of the Sokoloff and Patlak tracer kinetic models in estimating glucose metabolic rate (GMR) in the presence and absence of insulin; 2) evaluate the effect of nutritional state on the lumped constant (LC); and 3) compare the kinetics of 2-fluoro-2-deoxy-d-[14C]glucose (FDG) and 2-deoxy-d-[3H]glucose (DG) membrane transport and phosphorylation. The experimental preparation was the isolated, red blood cell-albumin-perfused rabbit heart. Our results showed that both tracer kinetic models provided GMR estimates that correlated well with the Fick method (for FDG, R = 0.84 and 0.91 for the Sokoloff and Patlak models, respectively); nutritional state did not affect the LC; and FDG and DG have different transport and/or phosphorylation parameters. We also observed that 1) the addition of a fourth compartment to the Sokoloff model reduced the mean squared error between measured and modeled data by a factor of 7.4; 2) a longer time (21.8 min) was required to obtain a linear phase of the Patlak plot than is allowed in clinical studies; and 3) accurate GMR estimates were obtained only by using different LCs reflecting insulins presence or absence. Our results indicate potential sources of error in the use of FDG and positron emission tomography to quantify GMR in patients.The purpose of this investigation was to 1) evaluate the relative accuracy of the Sokoloff and Patlak tracer kinetic models in estimating glucose metabolic rate (GMR) in the presence and absence of insulin; 2) evaluate the effect of nutritional state on the lumped constant (LC); and 3) compare the kinetics of 2-fluoro-2-deoxy-D-[14C]glucose (FDG) and 2-deoxy-D-[3H]glucose (DG) membrane transport and phosphorylation. The experimental preparation was the isolated, red blood cell-albumin-perfused rabbit heart. Our results showed that both tracer kinetic models provided GMR estimates that correlated well with the Fick method (for FDG, R = 0. 84 and 0.91 for the Sokoloff and Patlak models, respectively); nutritional state did not affect the LC; and FDG and DG have different transport and/or phosphorylation parameters. We also observed that 1) the addition of a fourth compartment to the Sokoloff model reduced the mean squared error between measured and modeled data by a factor of 7.4; 2) a longer time (21.8 min) was required to obtain a linear phase of the Patlak plot than is allowed in clinical studies; and 3) accurate GMR estimates were obtained only by using different LCs reflecting insulins presence or absence. Our results indicate potential sources of error in the use of FDG and positron emission tomography to quantify GMR in patients.

Prospective on the potential of imaging gene expression

The feasibility of the non-invasive imaging of gene expression is explored. Calculations of the possibility of the direct imaging of specific messenger RNA with radiolabeled antisense are discussed. In addition, possible mechanism for the amplification of the biological signal to enhance image detection are discussed.

[58] Carbon metabolism: Studies with radioactive tracers in vivo

Publisher Summary This chapter focuses on the studies with radioactive tracers in vivo of carbon metabolism. Photosynthetic carbon metabolism in cyanobacteria may be studied by exposing photosynthesizing cells to 14 CO 2 , subsequently killing the cells, and then separating and identifying the labeled metabolites by a suitable chromatographic technique. Certain types of kinetic tracer studies are complex and require specialized equipment. While these requirements are described in this chapter, simpler alternatives are presented for those interested in less complex or less quantitative investigations. The information obtained from tracer studies in vivo can be used not only to map metabolic pathways but also to study metabolic regulation, as has been the case with light-dark regulation in green algae. The present discussion is devoted mostly to the use of labeled substrates with whole cells and to alternative methods for analysis of the resulting labeled metabolites. The classic method of analysis by two dimensional paper chromatography is still the method of choice for some workers because of its capability of separating a broad range of metabolites such as sugar phosphates, sugars, amino acids, and carboxylic acids. Variations involving thin-layer chromatography and electrophoresis have been used with success and provide useful alternatives to paper chromatography.