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  • 1
    Electronic Resource
    Electronic Resource
    Protein binding of enprofylline (1983)
    Springer
    European journal of clinical pharmacology 25 (1983), S. 703-708 
    Details
    ISSN: 1432-1041
    Keywords: enprofylline ; 3-propylxanthine ; protein binding ; equilibrium dialysis ; theophylline ; ultrafiltration ; pH effect ; species differences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The protein binding of enprofylline, 3-propylxanthine, in plasma was studied by equilibrium dialysis and ultrafiltration under various experimental conditions. A limited comparison with theophylline was also undertaken. The mean fraction of enprofylline bound in human plasma at 20°C was 47.3±1.1% (SD), which was only 2% less than theophylline. The binding of the two drugs increased dramatically in the pH range 7.2 to 7.8, as reported previously for theophylline. Reasonable agreement was found between equilibrium dialysis and ultrafiltration, but the latter technique proved impractical, because pH control was difficult to achieve. A pronounced species difference in the binding of enprofylline was found. At pH 7.4 an almost constant level of binding of 57% in dog and 81% in rat was found up to 2 · 10−5 M (approx. 4 mg/l). Corresponding values in human and monkey plasma were 47 and 48%, respectively, up to 10−4 M (approx. 20 mg/l).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542362
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  • 2
    Electronic Resource
    Electronic Resource
    Studies on the histochemical “leucine aminopeptidase” reaction (1964)
    Springer
    Histochemistry and cell biology 4 (1964), S. 135-149 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A correlative chemical and histochemical study on the leucyl-β-naphthyl-amide-splitting activity is presented. In the first part comparison is made between homogenates and smears of strain L cells and ELD ascites tumor cells. It was concluded that only the available enzyme activity could be visualized by histochemical means. The growing tumor cells appeared to have more activity available than the strain L cells. The intensity of the histochemical LNAse reaction bore no correlation to the total enzymatic activity extractable. Most of the available activity seemed to reside in lysosome-like structures. Cell damage by repeated freezing and thawing increased the amount of activity available to substrate interaction. In the second part a comparison is made between chemical and histochemical results in four types of progressively growing transplanted or induced mouse tumors. Chemical data showed the occurrence of a mixed pattern of LNA-splitting enzymes, among which the previously described metal-dependent group constituted the main component in the tumor cells. In all cases and types of tumors a positive histochemical LNAse reaction was noticed both in growing tumor cells as well as in different parts of the stromal compartment. The intracellular reaction in tumor cells seemed confined mainly to lysosomal-like bodies. A positive stromal reaction seemed associated with the destructive (cytolytic and collagenolytic) activity at the tumor periphery. The stromal LNAse reaction was probably due to enzymes partly different from the intracellular ones. Additional enzymatic terms, including a chymotrypsin-like and/or a carboxypeptidase activity, may originate from various host cells. These contributions may be greatly increased by accumulation of inflammatory host cells as previously noted by Hess and Mottet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306155
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  • 3
    Electronic Resource
    Electronic Resource
    Estimation of technetium 99m mercaptoacetyltriglycine lasma clearance by use of one single plasma sample (1991)
    Springer
    European journal of nuclear medicine 18 (1991), S. 28-31 
    Details
    ISSN: 1619-7089
    Keywords: Technetium 99m mercaptoacetyltriglycine ; Plasma clearance ; Effective renal plasma flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recent studies have shown that technetium 99m mercaptoacetyltriglycine (MAG-3) is a suitable replacement for iodine 131 or 123 hippurate in gammacamera renography. Also, the determination of its clearance is of value, since it correlates well with that of hippurate and thus may be an indirect measure of renal plasma flow. In order to simplify the clearance method we developed formulas for the estimation of plasma clearance of MAG-3 based on a single plasma sample and compared them with the multiple sample method based on 7 plasma samples. The correlation to effective renal plasma flow (ERPF) (according to Tauxe's method, using iodine 123 hippurate), which ranged from 75 to 654 ml/min per 1.73 m2, was determined in these patients. Using the developed regression equations the error of estimate for the simplified clearance method was acceptably low (18–14 ml/min), when the single plasma sample was taken 44–64 min post-injection. Formulas for different sampling times at 44, 48, 52, 56, 60 and 64 min are given, and we recommend 60 min as optimal, with an error of estimate of 15.5 ml/min. The correlation between the MAG-3 clearances and ERPF was high (r = 0.90). Since normal values for MAG-3 clearance are not yet available, transformation to estimated ERPF values by the regression equation (ERPF=1.86 × CMAG-3 + 4.6) could be of clinical value in order to compare it with the normal values for ERPF given in the literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00177681
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  • 4
    Electronic Resource
    Electronic Resource
    Mate choice, fecundity and sexual dimorphism in two pipefish species (Syngnathidae) (1986)
    Springer
    Behavioral ecology and sociobiology 19 (1986), S. 301-307 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In order to understand the causes of sexual dimorphism, mate choice and size-related fecundity were studied in two pipefish species, Syngnathus typhle and Nerophis ophidion. Sexual dimorphism is more pronounced in N. ophidion; females are larger, have sexual colourings, and are more active during courtship. In S. typhle the sexes are alike in all these respects. Males brood their offspring in both species. In N. ophidion fecundity was positively correlated with both body size and the amount of sexual colouring in females. In males no correlation between body size and fecundity, or between body size and embryo size existed. Predictably, in mate choice experiments with equal-sized females, males chose females with more extensive sexual colourings. We explain sexual dimorphism in this species as a consequence of both natural selection (fecundity increases with size in females but not in males) and sexual selection (males prefer larger females). We argue that sexual size dimorphism did not evolve by selection minimizing overlap in food niches between the sexes, because food production is high in the Zostera beds where the fishes live, and no size dimorphism was found in the sympatrically occurring S. typhle. Furthermore, in N. ophidion dimorphism is not greater in a particular mouth character than in overall body size. In S. typhle egg size and the average number of eggs transferred per spawning were positively correlated with female body size. Apparently more energy per offspring was provided by larger males than by smaller males, and larger males also carried more offspring. As predicted, large mates were preferred by both sexes in mate choice experiments. This is explicable in terms of both natural selection (fecundity increases with size in both sexes) and sexual selection (both sexes prefer large mates). As a consequence of selection acting in the same direction in both sexes, sexual dimorphism is absent in S. typhle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300646
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    Paper (German National Licenses)
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