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  • 1
    Electronic Resource
    Electronic Resource
    Effect of respiratory acidosis on heart and circulation in cats, pigs, dogs and rabbits (1972)
    Springer
    Research in experimental medicine 158 (1972), S. 308-320 
    Details
    ISSN: 1433-8580
    Keywords: Respiratory Acidosis ; Cardiovascular Effects ; Sympathomimetic Amines ; Species Differences ; Respiratorische Acidose ; Kreislauf ; Sympathomimetica ; Speciesunterschiede
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An Katzen, Hunden, Kaninchen und Hausschweinen wurden in Pentobarbitalnarkose nach Muskelrelaxation mit Alloferin® bei geschlossenem Thorax die Auswirkungen einer akuten respiratorischen Acidose auf den Kreislauf sowie dessen Reaktion auf Pharmaka untersucht. 1. BeiKatzen undSchweinen steigen in respiratorischer Acidose Herzfrequenz, dp/dtmax und Blutdruck an; beiKaninchen bleiben dp/dtmax und Blutdruck nahezu unverändert. BeiHunden hingegen sinken Schlagfrequenz, dp/dtmax und Blutdruck in Acidose ab. Untersuchungen an Katzen, die mit Reserpin vorbehandelt waren, zeigten, daß eine respiratorische Acidose einen negativ inotropen und blutdrucksenkenden Eigeneffekt besitzt. Nach Vorbehandlung mit Phenoxybenzamin verursacht eine respiratorische Acidose bei Katzen einen Blutdruckabfall sowie einen Anstieg von dp/dtmax. Nach Vorbehandlung mit Pindolol verursacht eine Acidose eine Abnahme von Frequenz und dp/dtmax, während der Blutdruck konstant bleibt. Am unvorbehandelten Tier wird der negativ inotrope Effekt einer Acidose offenbar durch eine Stimulierung des sympathischen Nervensystems überdeckt, die bei Katzen und Schweinen am ausgeprägtesten ist. 2. DieWirkung sympathomimetischer Amine auf Herz und Kreislauf ist bei allen 4 untersuchten Tierarten in Acidose abgeschwächt, wobei die Abschwächung bei den Tieren mit der stärksten sympathischen Stimulation am ausgeprägtesten ist. 3. Biochemische Untersuchungen an Hunden und Katzen ergaben, daß in Acidose K+, Mg2+, anorganisches Phosphat und Glucose im Serum ansteigen, während der Magnesiumgehalt des Herzmuskels abnimmt.
    Notes: Summary In closed chest cats, dogs, rabbits and pigs, anaesthetized with pentobarbital and relaxed with diallylnortoxiferinium dichloride the effects of a respiratory acidosis on heart and circulation as well as their reaction to sympathomimetic amines were studied. 1. Incats andpigs a respiratory acidosis causes a rise of frequency, dp/dtmax of the left ventricle and systolic blood-pressure. Inrabbits an acidosis causes no significant alteration of blood-pressure and dp/dtmax. Indogs frequency, dp/dtmax and blood-pressure decline in acidosis. In cats pretreated withreserpine a respiratory acidosis causes a negative inotropic effect and a declining of blood-pressure. After pretreating cats withphenoxybenzamine in acidosis there results a decrease of blood-pressure, but a rise of dp/dtmax and frequency; after pretreating withpindolol in acidosis dp/dtmax and frequency decline, but blood-pressure remains unaltered. 2. The effectiveness of sympathomimetic amines on heart and circulation is diminished in acidosis. This diminution is most significant in those animals (cat, pig) with the most augmented sympathetic tonus in acidosis, but experiments performed with reserpinized cats indicated that the augmented sympathetic tonus can not be the only cause for the diminished efficiency of adrenergic stimulant amines in acidosis. 3. Biochemical studies performed in acidosis showed a rise of K+, Mg2+, inorganic phosphate and glucose in serum and a decrease of Mg2+ in the heart muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01852214
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of cyclophosphamide pretreatment of pregnant animals on the activity of nuclear DNA-dependent RNA-polymerases in different parts of rat embryos (1973)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 277 (1973), S. 71-88 
    Details
    ISSN: 1432-1912
    Keywords: Cyclophosphamide ; Embryonic Development ; DNA-Dependent RNA Polymerases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary On day 13+0 h of gestation rats received 10 mg/kg cyclophosphamide i.p. 3, 9, and 24 h after administration of the drug the activities of the DNA-dependent RNA polymerase reactions were measured in the whole embryo and in parts of it (head, upper and lower extremities and trunk). The activities of these enzymes were correlated with the increase in the RNA content of these tissues. A relationship was established light and electron microscopically between the biochemical results and the specific alterations which occur in different structures of the embryonic tissue. The results of these investigations show that: 1. cyclophosphamide leads-in dependency on the time-to a decrease or increase in the Mn++- and/or Mg++-stimulated RNA polymerase reactions in isolated cell nuclei of individual parts of the embryo 2. alterations in the enzyme activities of individual parts of the embryo are not detected when the enzyme activity of the whole embryo is measured at the early day 13 of gestation 3. towards the end of gestation malformations can be demonstrated only in those parts of the embryo, where 24 h after the administration of cyclophosphamide the enzyme pattern shows a highly significant deviation from that of the controls and where cell necroses can be demonstrated light and electron microscopically. Moreover, in the nucleolus of the neuroepithelium segregation of its components takes place which correlates well with the decreased r-RNA polymerase activity. In this paper a disturbance of the transcription mechanisms is discussed as being the primary mode of action of cyclophosphamide in cell metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00498786
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of isoprenaline and tyramine on the 45calcium uptake, the total calcium content and the contraction force of isolated guinea-pig atria in dependence on different extracellular hydrogen ion concentrations (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 274 (1972), S. 125-137 
    Details
    ISSN: 1432-1912
    Keywords: Sympathomimetic Amines ; pH ; 45Calcium Uptake ; Contraction Force ; Guinea-Pig Atria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Isolated, electrically stimulated left guinea-pig atria were incubated at 30° C in a Tyrode solution, the hydrogen ion concentration of which was varied by altering the percentage of the aerating CO2/O2-mixture. The increase of the extracellular hydrogen ion concentration from pH 8.0 to pH 7.0 caused a reduction of the 45calcium uptake and of the contraction force. The positive inotropic effect and the concomitantly occuring increased 45calcium uptake induced by isoprenaline and tyramine were markedly diminished at the lower pH, the response to tyramine being more affected by increased hydrogen ion concentration than that of isoprenaline. This is possibly due to a decrease in noradrenaline available at pH 7.0 for release by tyramine. Isoprenaline and tyramine enhanced the relative specific 45calcium activity (RSA) without altering the total tissue calcium content. On the contrary, the increase of the extracellular calcium concentration caused an augmentation of the relative specific 45calcium activity and the total tissue calcium content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00501847
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  • 4
    Electronic Resource
    Electronic Resource
    Studies on the teratogenic phase specificity of actinomycin D in the rat (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 275 (1972), S. 31-44 
    Details
    ISSN: 1432-1912
    Keywords: Embryonic Development ; Actinomycin D ; DNA-dependent RNA Polymerases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to elucidate the phase specificity of the embryo-lethal and teratogenic action of actinomycin D (day 5–10 of gestation) rats received 3H-actinomycin D at different times of gestation. The distribution of the radioactivity in the fetus and the placenta was measured. Moreover, the effects of actinomycin D on the RNA polymerase reactions in isolated nuclei of the decidual and fetal tissue were studied. The biochemical results were correlated electron microscopically with specific alterations occurring in different structures of the total implantation sites. These studies show that the time-dependent embryo-lethal and teratogenic effects of actinomycin D result from a lesion of the embryo and the decidua. The effects of the decidua occur at an earlier time and are more pronounced as compared to those of the embryo. Since the decidua is significant for the nutrition of the embryo till closure of the yolk-sac and beginning of the yolk-sac circulation (day 10 of gestation), the direct effects of actinomycin D on the embryo are intensified by the lesion of the decidua. After day 10 of gestation till the beginning of the placental function 3H-actinomycin D passes over to the embryo. But the concentration-even after a dose of 1 mg/kg-does not suffice to inhibit in vivo RNA polymerase reactions in isolated nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00505066
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  • 5
    Electronic Resource
    Electronic Resource
    Influence of steroid replacement therapy on rat embryos of hypophysectomised mother animals (1971)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 271 (1971), S. 103-110 
    Details
    ISSN: 1432-1912
    Keywords: Embryonic Development ; DNA Polymerase ; Hypophysectomy ; Sex Hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of estrone plus progesterone on embryonic survival were studied in hypophysectomised pregnant rats. Replacement therapy commenced 24 h prior to the ablation of the pituitary which was performed on day 6 of pregnancy. The number of viable fetuses was correlated with increasing amounts of progesterone from 24 to 84 mg/kg given in concert with a constant dose of 4 μg/kg estrone. As judged by the DNA content of the 14-day-old embryos, growth retardation was linked to the reduction of the progesterone levels. No visible malformations were recorded although the experimental period covered the phase of organogenesis. On the other hand, when measuring in isolated nuclei of 14-day-old rat embryos the activity of DNA polymerase, an enzyme the activity of which can be correlated to a certain extent to embryonic growth, it becomes obvious that after treatment with estrone in combination with low (24 or 36 mg/kg) or too high doses (84 mg/kg) of progesterone the correlation between DNA content of the embryos and DNA polymerase activity per cell diverges. This result may point to a cellular malfunction not disclosed by the macroscopic appearance of the embryos at this stage. So it can be concluded that embryonic growth and differentiation processes might be directly dependent on maternal gonadal hormones, at least till day 12 of pregnancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01002175
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