Search results for "guinea"
showing 10 items of 412 documents
Dissociation of theophylline uptake and inotropic effect in myocardial tissue: influence of temperature, pH and calcium.
1975
1. The myocardial uptake and the positive inotropic effect of theophylline (100 mug/ml; 0.56 mM) were studied in isolated electrically driven guinea-pig hearts perfused by the Langendorff technique under various extracellular conditions. [3H]-theophylline was used. 2. Variations in temperature, hydrogen ion and calcium ion concentrations of the perfusion media changed the time course and magnitude of the effect of theophylline on myocardial twitch tension but did not affect the time course and amount of theophylline uptake. 3. Under all conditions, the build-up of the positive inotropic effect of theophylline was about three times faster than the uptake of the drug into the heart. 4. Since …
Electrical and mechanical activity of mammalian heart muscle fibres treated with papaverine
1977
The action of papaverine on electrical and mechanical activity was investigated in ventricular and atrial heart muscle fibres from guinea-pigs and cats. 1. Papaverine (10−5 M–5×10−5M) had positive, negative or no inotropic effects in ventricular preparations; positive inotropic effects were not observed after pretreatment of the animals with reserpine. In atrial preparations, papaverine (2×10−5M) had a positive inotropic effect that was independent of endogenously stored catecholamines. 2. The effects of isoprenaline and dibutyryl cyclic AMP were potentiated by papaverine (10−5 M–2×10−5M). 3. The action potential duration was always prolonged by papaverine in ventricular as well as in atria…
Effect of DB-c-AMP on mechanical characteristics of ventricular and atrial preparations of several mammalian species
1974
Conflicting results exist about the influence of cyclic N6-2′-O-dibutyryl-AMP (DB-c-AMP) on myocardial contractile force. The present study was designed to examine whether the positive inotropic action of DB-c-AMP is restricted to certain model preparations or whether it can be assumed to represent a more general effect of the drug. Therefore, the effects of DB-c-AMP on myocardial force and on various parameters of the isometric contraction curve were examined in isolated electrically driven (0.5–2Hz) ventricular and atrial preparations of several mammalian species (cat, rabbit, calf, sheep, rat and guinea-pig). The following results were obtained:
Hypsipyrgias joseliae, a new species of lace bugs (Heteroptera: Tingidae: Tinginae) from New Guinea with a key to species of the genus Hypsipyrgias, …
2021
Hypsipyrgias joseliae sp. n. (Heteroptera: Tingidae: Tinginae) from New Guinea is described, illustrated and compared with its two relatives, namely H. telamonides Kirkaldy, 1908 from Australia, and H. euphues Drake and Ruhoff, 1962 from Lord Howe Island. Key to species of the genus Hypsipyrgias is also provided. Two genera very closely related to Hypsipyrgias Kirkaldy, 1908, namely Hypsotingis Drake, 1960 and Diplocysta Horváth, 1925 are re-diagnosed. Diplocysta globuliformis Hacker, 1928, D. papuana Drake, 1960, D. rustica, Drake, 1960 and D. thaleia Drake and Ruhoff, 1965 are transferred from Diplocysta to Hypsotingis.
Prostaglandin A2 (PGA2) increases the coronary vascular resistance in the guinea-pig isolated heart preparation.
1977
Prostaglandin A2 (PGA2) in concentrations of 1.5·10−8 to 3·10−6 M was found to produce concentration-dependent increase in the coronary vascular resistance of the guinea-pig isolated heart without alterations in myocardial contractile force and oxygen consumption.
Essential role of surface-bound chemoattractant in leukocyte migration
1977
MANY chemotactic factors, usually proteins or peptides, have been isolated and studied, but little is known about the basic mechanism of leukocyte migration. This movement is termed chemotaxis if its direction is determined by substances in the cells' environment1. The chemotactic agent is assumed to convey information to the leukocytes by interaction with receptors. The subsequent sequence of events thus triggered in the cells is unknown but metabolic changes such as activation of an esterase have been reported as occurring as the cells move forward (for review see ref. 2). A role for surface-bound chemoattractant in cell locomotion was suggested by the observation that mouse fibroblasts m…
Expressional downregulation of neuronal-type NO synthase I in guinea pig skeletal muscle in response to bacterial lipopolysaccharide
1997
AbstractWe have investigated the expression of neuronal-type NO synthase I (NOS I) and inducible-type NOS II in guinea pig skeletal muscle (diaphragm). Expression of NOS I mRNA and protein was highest in muscle of specific pathogen-free animals, lower in normally bred animals, and lowest in lipopolysaccharide (LPS)-treated animals. NOS II mRNA and protein levels were highest in muscle of LPS-treated animals. Elevated NOS activity in muscle from LPS-treated animals was less susceptible to the NOS I-selective inhibitor NG-nitro-l-arginine. Expressional downregulation of NOS I in sepsis may have implications for contractile function of skeletal muscle.
Antiasthmatic Effects of <i>Picrorhiza kurroa</i>: Androsin Prevents Allergen- and PAF-induced Bronchial Obstruction in Guinea Pigs
1991
In the Ayurvedic medicine, <i>Picrorhiza kurroa </i>Royle ex Benth. is used for the treatment of liver and lung diseases. Using different chemical and pharmacological methods, we could identify the phenol glycoside androsin as active compound preventing allergen and platelet-activating factor induced bronchial obstruction in guinea pigs in vivo (10 mg/kg p.o.; 1 h prior to the inhalation challenge). Histamine release from human polymorphonuclear leukocytes in vitro was inhibited by other compounds yet to be identified.
Histamine and its possible role in cytolysis of white blood cells in guinea pigs sensitized with tubercle bacilli.
1962
DELAYED or tuberculin-type sensitivity is–apart from some single publications–only transferable by white blood cells or peritoneal cells but not with humoral antibodies of sensitized organisms1. In vitro, after addition of antigen, a lysis of white blood cells2 is seen up to 35 per cent2. That effect is preceded by morphological changes3–5. Cytolysis in the presence of plasma will be discussed elsewhere. Labelled lymphoid cells of sensitized guinea pigs will be found after transfer to normal animals at the side of the dermal tuberculin reaction6. The importance of white cells is further revealed by the fact that the tuberculin reaction will be suppressed by a specific anti-lymphocytic serum…
Effect of in vivo stimulation of mice on the secretion of factor B of the alternative complement pathway by peritoneal macrophages
1977
After in vivo treatment of mice with thioglycollate medium, the amount of native factor B which could be detected in vitro in culture supernatants of peritoneal macrophages was much lower than that found in supernatants of macrophages taken from untreated mice. However, when the macrophages from thioglycollate medium-treated mice were cultured on a plastic surface covered with glutardialdehyde-linked bovine serum albumin, the culture supernatants contained larger quantities of native factor B than culture supernatants of macrophages from untreated mice under the same conditions. Thus, the effect of in vivo thioglycollate medium treatment on the in vitro secretion of factor B by peritoneal m…