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  • Physical Chemistry  (4)
  • Life and Medical Sciences  (3)
  • rat  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 80 (1990), S. 189-194 
    ISSN: 1435-1463
    Keywords: Nicotine enantiomers ; pain ; spinal analgesia ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spinalized rats received an intrathecal injection of either (−)-nicotine or (+)-nicotine in order to study the stereoselectivity of antinociception. Pain threshold was measured using the tail-flick test. Both stereoisomers had antinociceptive effects, but (−)-nicotine was up to 970 times more potent, depending on test conditions. The antinociceptive action of (−)-nicotine was antagonized by mecamylamine and yohimbine but not by naloxone and atropine. The findings show that spinal mechanisms are highly stereoselective toward nicotine, and suggest that primarily nicotinergic andalpha-adrenergic receptors are involved in its central antinociceptive effects.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 65 (1986), S. 135-145 
    ISSN: 1435-1463
    Keywords: Tranylcypromine enantiomers ; monoamine uptake ; monoamine release ; dopamine ; noradrenaline ; serotonin ; synaptosome ; imipramine binding ; blood platelet ; stereoselectivity ; rat ; rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Studies were carried outin vitro to determine effects of tranylcypromine enantiomers ([+]- and [−]-TCP) on uptake and release of 5-HT, DA and NA in rat synaptosomes and on imipramine binding to rabbit platelets. (+)-TCP was more potent than (−)-TCP as inhibitor of 5-HT uptake and imipramine binding, whereas (−)-TCP was more potent than (+)-TCP as inhibitor of DA and NA uptake. The enantiomers differed only slightly in their effects on monoamine release. The findings agree with previous reports on the stereoselectivity of monoaminergic mechanisms toward TCP enantiomers, and support the notion that the 5-HT uptake site may be associated with the imipramine binding site.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-1463
    Keywords: Phenylpiperazine ; monoamine uptake ; NA ; DA ; 5-HT ; MAO ; phenylethylamine ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The diastereomers of 3,N,N′-trimethyl-2-phenyl-1,4-piperazine dihydrochloride (TPP) were tested for their effects on NA, DA and 5-HT uptake in synaptosomes prepared from hypothalamus, corpus striatum, and frontal cortex, respectively. The diastereomers differed with respect to their inhibitory properties. (2R, 3R)-TPP was more potent than the other diastereomers on NA and DA uptake, whereas (2S, 3S)-TPP was least potent. In contrast, the (2S, 3S)- and (2 S, 3R)-diastereomers of TPP were more potent than (2R, 3R)- and (2R, 3S)-TPP as inhibitors of 5-HT uptake. None of the diastereomers affected monoamine oxidase activity. The findings show that the diastereomers of TPP interact stereoselectively with neuronal mechanisms for monoamine uptake, and that the (S)-configuration at the 2 carbon is important for inhibitory actions of TPP on 5-HT uptake.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of the mid-gut epithelium and regenerative cells of larvae of a moth (Ephestia kühniella) is described. Particular attention is paid to the absorptive and goblet cells and their lateral junctions; these features are discussed in terms of the digestive and regulatory functions of the epithelium. One digestive pathway has been investigated with the aid of ingested ferritin; intake of this marker by endocytosis and the evident involvement of Golgi vesicles in the transformation of endocytic vesicles into multivesicular bodies, together with the fate of the latter, are discussed in terms of the digestive function of this part of the alimentary tract and of the lysosome concept.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 176 (1973), S. 125-127 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We have undertaken a study to coordinate examination of thin sections with that of freeze-etched material. Results suggest that (1) lamellar bodies have a much more regular structure than hitherto believed. (2) The leaflets of some lamellar bodies reveal a unique substructure of ribs and intramembranous particles displayed in form and spacing (400-500 Å) like those of tubular myelin as seen in the airspace. (3) As in other membranes of high metabolic activity the fracture face is covered with particles 80-100 Å in diameter. Our freeze-etch findings of the previously undetected organization and suborganization of lamellar bodies suggest an entirely new set of morphological criteria for evaluating the maturation of lamellar bodies and their role in the intracellular assembly of the reticular components of the airspace lining.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 24 (1992), S. 199-215 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethyl tertiary butyl ether (ETBE) is being proposed as an additive for use in reformulated gasolines. In this study, experiments were performed to examine the kinetics and mechanism of the atmospheric removal of ETBE. The kinetics of the reaction of ETBE with OH radicals were examined by using a relative rate technique with the photolysis of methyl nitrite to generate OH radicals. With n-hexane as the reference compound, a value of (9.73 ± 0.33) × 10-12 cm3 molecule-1 s-1 was obtained for the rate constant. The OH rate constant for t-butyl acetate, a product of the oxidation of ETBE, was (4.4 ± 0.4) × 10-13 cm3 molecule-1 s-1 at 298 K.The primary products and molar yields for the OH reaction with ETBE in the presence of NOx were t-butyl formate (0.64 ± 0.03), t-butyl acetate (0.13 ± 0.01), ethyl acetate (0.043 ± 0.003), acetaldehyde (0.16 ± 0.01), acetone (0.019 ± 0.002), and formaldehyde (0.53 ± 0.04). Under the described reaction conditions, the formation of t-butyl nitrite was also observed. From these molar yields, approximately 98% of the reacted ETBE could be accounted for by paths leading to these products. Chemical mechanisms to explain the formation of these products are presented.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ [u.a.] : Wiley-Blackwell
    Journal of Orthopaedic Research 7 (1989), S. 590-598 
    ISSN: 0736-0266
    Keywords: Wrist ; Kinematics ; Fracture ; Scaphoid ; Life and Medical Sciences
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The effects of a scaphoid osteotomy on the kinematics of the carpal bones were determined in five cadaveric wrist specimens. Minute radiographic markers were inserted into the distal radius and selected carpal bones through limited arthrotomies between the intercarpal ligaments. Simultaneous biplanar radiographs were obtained in neutral and the extreme wrist positions of extension, flexion, radial deviation, and ulnar deviation, both before and after a scaphoid waist osteotomy. The positions of each of the carpal markers and their corresponding carpal bones were digitized for each wrist position, and a computer-assisted motion analysis was performed for each specimen before and after transverse scaphoid waist osteotomy. Following the osteotomy, there was a tendency for the scaphoid osteotomy to collapse into a dorsally angulated or “humpback collapse” deformity during each extreme wrist position. There was also multiplanar osteotomy site motion as well as complex collapse deformities of the midcarpal joint associated with loss of the mechanical tie-rod function of the scaphoid. These findings reveal the importance of the scaphoid in maintaining normal kinematics and the inherent instability of these fractures with loss of scaphoid integrity.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 23 (1991), S. 907-924 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl tertiary butyl ether (MTBE) has been proposed and is being used as an additive to increase the octane of gasoline without the use of tetraethyl lead and alkylbenzenes. The present experiments have been performed to examine the kinetics and mechanisms of the atmospheric removal of MTBE. The kinetics of the reaction of OH with MTBE was examined by using a relative rate technique in which photolysis of methyl nitrite was used as the source of OH. With n-butane as the reference compound a value of (2.99 ± 0.12) × 10-12 cm3 molecule-1 s-1 at a temperature of 298 K was obtained for the rate constant. The products (and product yields) for the OH reaction with MTBE in the presence of NOx were also determined and found to be t-butyl formate (0.68 ± 0.05), methyl acetate (0.14 ± 0.02), acetone (0.026 ± 0.003), t-butanol (0.062 ± 0.009), and formaldehyde (0.48 ± 0.05) in mols/mol MTBE converted. The OH rate constant for the major product formed, t-butyl formate was also measured and found to be (7.37 ± 0.05) × 10-13 cm3 molecule-1 s-1. Mechanisms to rationalize the formation of the products are presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 27 (1995), S. 453-472 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tertiary-amyl methyl ether (TAME) is proposed for use as an additive to increase the oxygen content of gasoline as stipulated in the 1990 Clean Air Amendments. The present experiments have been performed to examine the kinetics and mechanisms of the atmospheric removal of TAME. The kinetics of the reaction of OH with TAME was examined by using a relative rate technique in which photolysis of methyl nitrite or nitrous acid was used as the source of OH. The OH rate constant for TAME and two major products (t-amyl formate and methyl acetate) were measured and yields for ten products were determined as primary products from the reaction.Values determined for the rate constants for the reaction with OH were 5.48 × 10-12 (TAME), 1.75 × 10-12 (t-amyl formate), and 3.85 × 10-13 cm3 molec-1 s-1 (methyl acetate) at 298 ± 2 K. The primary products (with corrected yields where required) from the OH + TAME that have been observed include (1) t-amyl formate (0.366), methyl acetate (0.349), acetaldehyde (0.43, corrected), acetone (0.036), formaldehyde (0.549), t-amyl alcohol (0.026), 3-methyoxy-3-methyl-butanal (0.044, corrected), t-amyloxy methyl nitrate (0.029), 3-methyoxy-3-methyl-2-butyl nitrate (0.010), and 2-methoxy-2-methyl butyl nitrate (0.004). Mechanisms leading to these products involve OH abstraction from each of the four different hydrogen atoms of TAME. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 28 (1996), S. 475-480 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas-phase reaction products of the OH radical with 2-ethoxyethyl acetate (EEA, CH3C(O)OCH2CH2OCH2CH3) have been investigated. 1,2-Ethanediol acetate formate (EAF, CH3C(O)OCH2CH2OC(O)H) and ethyl formate (EF, HC(O)OCH2CH3) were identified as the two main products. A third product, ethylene glycol diacetate (EGD, CH3C(O)OCH2CH2OC(O)CH3), was also observed. EAF, EF, and EGD formation yields were determined to be 0.37 ± 0.03 and 0.328 ± 0.018 and 0.040 ± 0.005, respectively. Proposed reaction mechanisms are discussed and compared with these data. © 1996 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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