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  • Analytical Chemistry and Spectroscopy  (100)
  • Organic Chemistry  (23)
  • Autoradiography  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Uptake and retention of3H-estradiol by gonadotrophs and lactotrophs in the pituitary glands of the guinea pig, hamster and gerbil (1987)
    Springer
    Cell & tissue research 248 (1987), S. 75-78 
    Details
    ISSN: 1432-0878
    Keywords: LH-cells ; Prolactin cells ; Immunocytochemistry ; Estrogen ; Autoradiography ; Guinea pig ; Hamster ; Gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nuclear uptake and retention of3H-estradiol by luteinizing hormone (LH) and prolactin (PRL) cells was examined in three species of rodents (guinea pigs, hamsters and gerbils) using the combined techniques of immunocyto-chemistry and autoradiography. Castrated animals were injected with3H-estradiol and decapitated 1.5 h later. The pituitary glands were processed for thaw-mount autoradiography followed by conventional immunocytochemical staining for LH and PRL.3H-estradiol accumulated in more than 80% of the anterior pituitary cells in the gerbils, while only 33 and 22% of the cells accumulated3H-estradiol in the hamsters and guinea pigs, respectively. A varying percentage of immunoreactive LH and PRL cells in all three species were found also to contain binding sites for estradiol. Some LH and PRL cells in hamsters and guinea pigs and only some in PRL cells of gerbils were found to be devoid of grains. Quantitative analysis revealed that the number of grains per nucleus differed considerably from cell to cell. LH cells of guinea pigs accumulated much larger amounts of3H-estradiol than did the PRL cells, while the LH cells in the hamsters and gerbils accumulated only slightly more3H-estradiol than the PRL cells. These results confirm the previous observations in rats and baboons that demonstrated tremendous species differences in percentage of cells in the anterior pituitary gland that accumulated3H-estradiol. Also, these data suggest that there are functionally heterogeneous cell types among the LH and PRL cells in hamsters, guinea pigs and gerbils as has been previously demonstrated in rats and baboons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01239965
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  • 2
    Electronic Resource
    Electronic Resource
    Spectrophotometric and Nuclear Magnetic Resonance Study of Temperature- and Pressure-induced Changes in the Intimate Solvation of Neodymium (III) in N, N-Dimethylformamide and Trimethylphosphate (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 1025-1028 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The temperature- and pressure-dependent equilibria for the addition of an extra N, N-dimethylforrnamide (DMF) or trimethylphosphate (TMP) ligand onto [Nd (DMF)8]3+- and [Nd(TMP)6]3+-species respectively have been measured by visible spectrophotometry. Complementary NMR. studies on other lanthanide ions show a gradual shift in preference for the lower coordination number across the lanthanide series.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650333
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of Linear Oligomers of (R)-3-Hydroxybutyrate and Solid-State Structural Investigations by electron microscopy and X-ray scatteringDedicated to Prof. Dr. H. Ringsdorf on the occasion of his 65th birthday (1994)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 77 (1994), S. 1099-1123 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Repetitive treatment of the biopolymer P(3-HB) (molecular weight 〉 105 Dalton, storage or s-P(3-HB)), with lithium hexamethyl disilazanid (LHMDS) at -70° in THF leads to a mixture of oligomers with increasingly sharp distribution around a 15-, 30-, and 45mer. Discrete fragments are also isolated when P(3-HB) is heated under reflux (89°) in neat Et3N. Linear oligo(3-HB) derivatives (3-7) containing up to 96 3-HB units are synthesized using an exponential segment-coupling strategy. These oligomers are used to calibrate size-exclusion chromatography columns for the analysis of oligo(3-HB) samples from the different sources. The linear oligo-(3-HB) derivatives also served as a model with respect to the physical properties of high molecular weight P(3-HB) and were investigated as such by transmission electron microscopy (TEM) and by small- and wide-angle X-ray scattering (SAXS and WAXS). The thicknesses of the lamellar crystallites (long periods) formed by the 8mer, 16mer, and 32mer, are ca. 26, 52, and 53 Å, respectively, indicating that the 32mer molecules are folded once, very tightly, into a ‘hair-pin’-type conformation. High-molecular-weight P(3-HB), which was crystallized in a similar way, also has a lamellar crystallite thickness of ca. 50-65 Å. Thus, the treatment of P(3-HB) with LHMDS at low temperature causes etching of the amorphous regions, an effect well known in polymer science for studying the regularity of chain folding. The ca. 50-Å packing within the tight folds of P(3-HB) is discussed in view of its possible function in ion transport through cell membranes.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19940770423
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  • 4
    Electronic Resource
    Electronic Resource
    High-Pressure Stopped-Flow Study of the Kinetics of Base Hydrolysis of the Dichromate Ion by Hydroxide Ion, Ammonia, Water, and 2,6-Lutidine in Aqueous Solution (1983)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 66 (1983), S. 2445-2448 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Volumes of activation for the base hydrolysis of the dichromate anion have been measured at 298.2 K, using high-pressure stopped-flow spectrophotometry. The values of ΔV* (cm3 · mol-1), - 17.9 ± 0.6, - 19.2 ± 0.9, - 24.9 ± 0.9 and - 26.0 ± 0.7 for OH-, NH3, H2O and 2,6-lutidine, respectively, are consistent with an interchange mechanism with associative activation mode (Ia).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19830660809
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  • 5
    Electronic Resource
    Electronic Resource
    Dendrimers with Porphyrin Cores: Synthetic models for globular heme proteins (1997)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 80 (1997), S. 1773-1801 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dendritic iron porphyrins were synthesized as functional mimics of globular electron-transfer heme proteins. The cascade molecules 1 · Zn-3 Zn of first to third generation were obtained starting from the (meso-diarylporphyrin) zinc 6 · Zn which contains four carboxylate arms for attachment of the poly(ether-amide) dendritic branches by peptide-coupling methodology (Scheme 1). Generation 3 compound 3 · Zn with 108 methyl-carboxylate end groups has a molecular weight of 19054. D, and computer modeling suggests that its structure is globular and densely-packed, measuring ca. 4 nm in diameter and, therefore, similar in dimensions to the electron-transfer protein cytochrome-c. Starting from the generation 1 poly(carboxylic acid) 11 · Zn and the generation 2 analog 12 · Zn the dendritic ZnII porphyrins 4 · Zn and 5 · Zn, respectively, were obtained by esterification with triethyleneglycol monomethyl ether (Schemes 3 and 4). Demetallation followed by insertion of FeII and in situ oxidation afforded the water-soluble dendritic iron porphyrins 4 FeCl and 5 FeCl. The electrochemical behavior of esters 1 · Zn-3 · Zn in organic solvents changed smoothly with increasing dendritic generation (Table 1). Progressing from 1 · Zn to 3 · Zn in THF, the first porphyrin-centered oxidation and reduction potentials become more negative by 320 and 210mV, respectively. These changes were attributed to strong microenvironmental effects imposed on the electroactive core by the densely packed dendritic surroundings. The electrochemical properties of 4 · FeCl and 5 · FeCl were investigated by cyclic voltammetry in both CH2Cl2 and H2O (Tables 2 and 3). Progressing from 4 · FeCl to 5 · FeCl in CH2Cl2, the redox potential of the biologically relevant FeIII/FeII couple remained virtually unchanged, whereas in aqueous solution, 5 FeCl exhibited a potential 420 mV more positive than did 4 FeCl. The large difference between these potentials in H2O was attributed to differences in solvation of the core electrophore. Whereas the relatively open dendritic branches in 4 · Fecl do not impede access of bulk solvent to the central core, the densely packed dendritic superstructure of 5 · FeCl significantly reduces contact between the heme and external solvent. As a result, the more charged FeIII state is destabilized relative to FeII, and the redox potential is strongly shifted to a more positive value.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19970800603
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  • 6
    Electronic Resource
    Electronic Resource
    Tutorial to robust statistics (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 1-20 
    Details
    ISSN: 0886-9383
    Keywords: Averaging ; Median ; Outliers ; Regression ; Residuals ; Robustness ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this tutorial we first illustrate the effect of outliers on classical statistics such as the sample average. This motivates the use of robust techniques. For univariate data the sample median is a robust estimator of location, and the dispersion can also be estimated robustly. The resulting ‘z-scores’ are well suited to detect outliers. The sample median can be generalized to very large data sets, which is useful for robust ‘averaging’ of curves or images. For multivariate data a robust regression procedure is described. Its standardized residuals allow us to identify the outliers. Finally, a survey of related approaches is given. (This review overlaps with earlier work by the same author, which appeared elsewhere.)
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050103
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  • 7
    Electronic Resource
    Electronic Resource
    Physical properties of matrices used for fast atom bombardment (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 492-497 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Physical and chemical properties of common matrices are tabulated, with aims of facilitating rational matrix selection and providing input for fundamental studies of matrix-assisted ionization. The rationale for selecting tabulated properties is discussed.
    Additional Material: 10 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200180708
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  • 8
    Electronic Resource
    Electronic Resource
    Enantioselective pharmacodynamics of the nonsteroidal antiinflammatory drug ketoprofen: In vitro inhibition of human platelet cyclooxygenase activity (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 484-487 
    Details
    ISSN: 0899-0042
    Keywords: ketoprofen enantiomers ; thromboxane ; in vitro activity ; 2-arylpropanoic acids ; sigmoidal Emax modelling ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pharmacological activity of ketoprofen enantiomers was investigated in humans by an in vitro method. The antiplatelet effect of ketoprofen was assessed by measuring the inhibition of platelet thromboxane B2 (TXB2) generation during the controlled clotting of whole blood obtained from each of four healthy volunteers. Ketoprofen was added separately to whole blood as a range of concentrations of (1) predominantly (S)-ketoprofen, (2) racemic ketoprofen, and (3) predominantly (R)-ketoprofen. (S)-Ketoprofen was found to be solely active at inhibiting human platelet TXB2 production; (R)-ketoprofen was devoid of such activity and did not modify the potency of its optical antipode. A relationship between the percentage inhibition of TXB2 generation and the unbound concentration of (S)-ketoprofen in serum was modelled according to a sigmoidal Emax equation. The mean (±SD) serum unbound concentration of (S)-ketoprofen required to inhibit platelet TXB2 generation by 50% (EC50) was 0.320 (±0.062) ng/ml. This value for ketoprofen is considerably lower than previously reported values for (S)-ibuprofen and (S)-naproxen. © 1992 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040805
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  • 9
    Electronic Resource
    Electronic Resource
    Stereoselective analysis of ketorolac in human plasma by high-performance liquid chromatography (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 31-35 
    Details
    ISSN: 0899-0042
    Keywords: ketorolac enantiomers ; HPLC ; plasma concentrations ; nonnarcotic analgesic ; nonopiate analgesic ; diastereomers ; nonsteroidal antiinflammatory drugs (NSAIDs) ; stereoselective pharmacokinetics ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A high-performance liquid chromatographic (HPLC) analytical method is described for the quantification of the (R)- and (S)-enantiomers of ketorolac when present together in human plasma. The method involves derivatization with thionyl chloride/(S)-1-phenylethylamine and subsequent reversed-phase chromatography of the diastereomeric (S)-1-phenylethylamides of (R)- and (S)-ketorolac. The method is suitable for the analysis of large numbers of plasma samples and has been applied in this report to a pharmacokinetic study of ketorolac enantiomers upon intramuscular administration of racemic drug to a human subject. The limit of quantification for each enantiomer of ketorolac is 50 ng/ml (signal-to-noise ratio 〉 10). © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530050107
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  • 10
    Electronic Resource
    Electronic Resource
    Iridium complexes of dehydroamino acids: The kinetic resolution of racemic diphosphines and their application in catalytic asymmetric hydrogenation (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 3 (1991), S. 345-354 
    Details
    ISSN: 0899-0042
    Keywords: iridium ; asymmetric hydrogenation ; dehydroamino acid esters ; enamide complexes ; resolution ; homogeneous catalysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of chiral diphosphines with a configurationally pure cationic bis-enamide complex of iridium, bis(menthyl (Z)-α-benzamidocinnamate)-iridium tetrafluoroborate, is described. When the reactant ligand is racemic then kinetic resolution occurs with high specificity under the appropriate conditions. Since the iridium diphosphine complex is catalytically inactive in homogeneous hydrogenation, the residual enantiomer may be reacted with bis(norbornadiene)-rhodium tetrafluoroborate to produce an active catalyst. This effects the hydrogenation of methyl (Z)-α-acetamidocinnamate in optical yields comparable with those obtained separately with the enantiomerically pure ligand rhodium complex. The reaction of pure (+)- or (-)-enantiomer of bis(menthyl (Z)-α-benzamidocinnamate)-iridium tetrafluoroborate with enantiomerically pure diphosphines has been studied. Invariably one hand of the diphosphine reacts rapidly with a given enantiomer of the iridium complex to give a stable diphosphine iridium enamide complex in which the original configuration of the coordinated olefin is maintained. The other combination of enantiomers reacts much more slowly, in keeping with the kinetic resolution work, and produces an enamide complex which is unstable in solution, isomerising to a second diastereomer. Since the absolute configuration of the iridium bis-enamide complex has been established by X-ray crystallography, this experiment affords a method of determining the configuration of rhodium enamide complexes in asymmetric hydrogenation (assuming structural homology between Rh and Ir). In all cases the disfavoured enamide complex was the one involved in the catalytic pathway.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530030421
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