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Biomedical subjects

F E Regnier

Publications and source records attributed to F E Regnier.

143 records · Page 8Linked to original sources

Rapid assessment of isoenzymes by high-performance liquid chromatography.

We describe the rapid profiling of isoenzymes by use of microparticulate anion-exchange chromatography supports and a continuous, post-separation enzyme detector in a high-performance liquid chromatograph. Chromatographic analysis and enzyme detection are fully automated and provide excellent reproducibility. Factors affecting the isoenzyme profile and detector response characteristics are assessed. Lactate dehydrogenase and creatine kinase isoenzymes in tissue extracts, control materials used as electrophoretic standards, and serum were profiled by this method to establish the resolution and reliability of the method. We show the clinical use of this method in detecting changes in these isoenzymes in serum associated with acute myocardial infarction.

Animals↗

A continuous-flow enzyme detector for liquid chromatography.

A detection system has been developed for the selective and sensitive detection of enzymes eluting from a liquid chromatographic column. This system monitors a reaction that the enzyme catalyzes and provides a chemical amplification ranging from 10(4) to 10(5). The detection system consists of a reagent or substrate pump, a post-column reactor packed with non-porous spherical glass beads, and a photometric detector. A linear and selective response to a series of enzymes of clinical importance is demonstrated.

Alcohol Oxidoreductases↗

Glycerolpropylsilane bonded phases in the steric exclusion chromatography of biological macromolecules.

Glycerolpropylsilane bonded phases have been found to control the adsorption and/or denaturation of proteins and nucleic acids on controlled porosity glass supports. The bonded-phase thickness is 18-19A while the amount of glycerol moiety varies from 80 to 150 mumoles/g depending on support pore diameter. It has been demonstrated that carbohydrate bonded supports may be used in the chromatography of proteins, nucleic acids, and polysaccharides.

Adsorption↗

Identification of a ventral scent marking pheromone in the male Mongolian gerbil (Meriones unguiculatus).

Sebum from the ventral scent marking gland of the male Mongolian gerbil was fractionated and tested for its ability to elicit behavioral response in a conditioning task and in a stimulus preference situation. The active fraction was identified as phenylacetic acid; both it and a synthetic sample elicited the same behavioral response. Phenylacetic acid appears to be a major pheromone of the male Mongolian gerbil.

Animals↗

Chemical communication and "propaganda" in slave-maker ants.

Slave-maker ants of the Formica sanguinea group direct their raids by means of odor trails. Artificial trails made from whole-body extracts and extracts of Dufour's glands and hindguts can be used to guide columns of workers to selected target colonies and to initiate raids. In workers of F. pergandei and F. subintegra, members of the F. sanguinea group, the Dufour's glands are hypertrophied and contain large quantities of three acetates (decyl, dodecyl, and tetradecyl), which are discharged at defending workers during the slave raids. The acetates produce very efficient, long-lasting alarm signals that attract the slave-makers but disperse the defenders; in effect, therefore, they are "propaganda substances."

Acetates↗

Pheromones.

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Acetates↗

Insect pheromones.

The evidence for intraspecies chemical communication in insects is reviewed, with emphasis on those studies where known organic compounds have been implicated. These signal-carrying chemicals are known as pheromones. There are two distinct types of pheromones, releasers and primers. Releaser pheromones initiate immediate behavioral responses in insects upon reception, while primer pheromones cause physiological changes in an animal that ultimately result in a behavior response. Chemically identified releaser pheromones are of three basic types: those which cause sexual attraction, alarm behavior, and recruitment. Sex pheromones release the entire repertoire of sexual behavior. Thus a male insect may be attracted to and attempt to copulate with an inanimate object that has sex pheromone on it. It appears that most insects are rather sensitive and selective for the sex pheromone of their species. Insects show far less sensitivity and chemospecificity for alarm pheromones. Alarm selectivity is based more on volatility than on unique structural features. Recruiting pheromones are used primarily in marking trails to food sources. Terrestrial insects lay continuous odor trails, whereas bees and other airborne insects apply the substances at discrete intervals. It appears that a complex pheromone system is used by the queen bee in the control of worker behavior. One well-established component of this system is a fatty acid, 9-ketodecenoic acid, produced by the queen and distributed among the workers. This compound prevents the development of ovaries in the workers and inhibits their queen-rearing activities. In addition, the same compound is used by virgin queen bees as a sex attractant.

Alcohols↗

Chemiluminescent detection for capillary electrophoresis and EMMA enzyme assays.

A large number of analytically and physiologically significant enzymes produce or consume hydrogen peroxide (H2O2). Post-column reaction of H2O2 with luminol in an alkaline solution results in chemiluminescence. A prototype reactor/detector for CE with chemiluminescent detection (CLD) of H2O2 was constructed and utilized. Two variations of the detection cell illustrated the difference between an analyte-limiting (stagnant-cell) and a window-limiting (swept-cell) detection scheme. The stagnant-cell detector had a low limit of detection (39 fmol at S/N = 3), but poor separation efficiency (1100 theoretical plates). The swept-cell detector demonstrated greater efficiency (226,000 theoretical plates), but a detection limit one order of magnitude higher (380 fmol). Several enzyme assays were developed using electrophoretically mediated microanalysis (EMMA) with chemiluminescent monitoring of H2O2. EMMA can be used to perform enzyme assays in a capillary format using electrophoretic mixing. Accumulated product of an incubation is swept to the detector and traditionally monitored by UV-VIS absorbance, fluorescence, or electrochemical detection. Higher sensitivity may also be obtained from the use of CLD. Chemical amplification with galactose oxidase and glucose oxidase resulted in the production of H2O2, while catalase enzymatically consumed H2O2. This work showed a CLD limit of 9300 molecules in the case of catalase.

Catalase↗