Publications by authors named "Keller W"

Culture of Brassica campestris anthers at 35°C for one or three days prior to culture at 25°C significantly stimulated the yield of microspore-derived embryos. More than 100 plants were regenerated from cultured embryos and haploids were identified amongst them. The haploid frequency was greater than 70% if all small-flowered sterile plants were considered to be haploid.

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The biosynthetic conversion of epinephrine to normacromerine in Coryphantha macromeris (Engelm.) Br. and R.

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Electrical stimulation was applied to the spinal cord of 75 patients who had demyelinating and degenerative diseases of the central nervous system, and 3 patients who had sustained spinal cord injuries. The electrical energy was delivered to the central nervous system by the percutaneous technique. The amount of electrical energy required to produce the perception of paresthesias was measured in 11 patients.

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Simian virus 40 nucleoprotein complexes undergo an ionic strength-dependent structural transition. At moderate ionic strength they contain histone H1 as well as the nucleosomal histones and have a compact conformation with globular subunits 190 angstroms in diameter. At high ionic strength histone H1 is released, and the structure unfolds into chains with an average of 24 nucleosomes.

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20 patients--15 to 71 years old--, who underwent maxillofacial operations received Sokoham for 10 days via a nasogastric tube. In 0.8% of all applications vomiting occurred.

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The structure of SV 40 chromatin.

Philos Trans R Soc Lond B Biol Sci

May 1978

Simian virus 40 (SV40) nucleoprotein complexes were studied with the electron microscope. Depending on the isolation procedure, SV40 chromatin has two different conformations: complexes isolated in the presence of 0.15 M NaCl appeared as very compact globular structures, while those isolated in the presence of 0.

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TLC and GLC of an alkaloid extract of the aboveground portions of Lupinus argenteus Pursh. var. stenophyllus (Rydb.

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SV40 chromatin can be isolated in two forms: At moderate ionic strength (mu = 0.1-0.3) it contains histone H1 in addition to the four nucleosomal histones and has a highly condensed appearance in the electron microscope, being composed of a few closely connected large spheres [190 A (160, 220) diameter].

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The seeds of Sophora secundiflora (mescalbeans) have been purported to have hallucinogenic activity because of their past use in certain Native American ceremonies during which visions were experienced by those consuming the seeds. Chemical analysis of mescalbeans revealed the absence of detectable amounts of tryptamine derivatives; however, two additional quinolizidine alkaloids, epi-lupinine and delta5-dehydrolupanine, were isolated. Thus far, seven quinolizidine alkaloids have been detected in mescalbeans and quantitation of these constituents showed that the major alkaloid present is cytisine (o.

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The cactus alkaloid 3,4-dimethoxyphenethylamine and its naturally occurring N-methylated homologs inhibited the deamination of tyramine and tryptamine by rat brain monoamine oxidase. In contrast, the beta-hydroxylated derivatives of this series failed to inhibit the action of monoamine oxidase on both tyramine and tryptamine.

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Condensate from different modified cigarettes were compared with condensate from a standard cigarette with regard to its tumorigenic activity on mouse skin. Significant lower effects were observed in test series with cigarettes from expanded tobacco. Different results were obtained in experiments with cigarettes from the new smoking materials.

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A new gas chromatographic method reliable in the microgram range, was developed to measure ETU residues in various crops. Contrary to previously published procedures, this new method does not require prior derivatization of the ETU. The limit of sensitivity was shown to be 0.

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This paper presents recommendations for the analysis and presentation of height and weight data from surveillance or surveys involving nutrition and anthropometry in young children up to the age of 10 years. These recommendations are only for the analysis of data collected on a cross-sectional basis. The basic indices recommended are height for age and weight for height, each considered either in terms of centiles or in a cross-classification scheme using standard deviation scores.

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It has been established that the oxidative deamination of tyramine by monoamine xodase is inhibited by (+/-)-4-methoxy-beta-hydroxyphenethylamine and its N-methylated derivatives. This particular series of compounds does not inhibit the action of monoamine oxidase when tryptamine is used as the substrate. In contrast, 4-methoxyphenethylamine and its N-methylated homologs inhibit the monoamine oxidase-catalyzed deamination of both tyramine and tryptamine.

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Senescence occurs in all wild strains of Podospora anserina after continued growth. This syndrome can be inhibited by a synergistic interaction of two linked genes, incoloris and vivax. Whereas the wild strain starts to become senescent after 26 d and the mutants incoloris and vivax after 42 and 66 d respectively, the double mutant shows no signs of aging after culture for more than one year.

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Closed-circular, superhelical DNA from simian virus 40 (SV40 DNA I) was treated with an excess of DNA-relaxing enzyme in the presence of increasing amounts of ethidium bromide (EtdBr). After removal of the ethidium, each sample consisted of a group of close-circular DNA molecules differing in their number of superhelical turns (tau) around a mean value of tau in a Gaussian-like distribution. The DNA samples were analyzed by electrophoresis in agarose gels under conditions where the electrophoretic mobility was a function of the number of superhelical turns.

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The synthesis and selected pharmacological testing of (+/-)-4-methoxy-beta-hydroxyphenethylamine [1-(4-methoxyphenyl)-2-aminoethanol] and its N-methylated derivatives are presented. Members of this series were found to exert partial prevention of reserpine-induced hypothermia in mice and to inhibit monoamine oxidase in Warburg studies. Activity was essentially dose dependent.

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Superhelical simian virus 40 DNA migrates more rapidly during electrophoresis in agarose gels than covalently closed DNA free of superhelical turns (relaxed DNA). The difference in electrophoretic mobility between superhelical and relaxed DNA was used to monitor the activity of a protein from human tissue culture cells which converts superhelical DNA into relaxed DNA. Purified DNA-relaxing protein removes both negative and positive superhelical turns and acts in a catalytic manner.

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Stepwise relaxation of supercoiled SV40 DNA.

Cold Spring Harb Symp Quant Biol

November 1975

We have shown in this paper that agarose gel electrophoresis can be used to examine the tertiary structure of supercoiled SV40 DNA. Differences as small as one superhelical turn can be detected by this method. When used as an assay, it enabled us to purify from human tissue culture cells a protein which acts on supercoiled DNA, leading to a gradual removal of its superhelical turns.

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