Search results for "Pigs"
showing 10 items of 331 documents
Diffusion in slice preparations bathed in unstirred solutions
1987
A diffusion model is described here, which allows for the estimations of drug concentration changes in porous media, such as in slice tissues of the central nervous system (CNS) bathed in unstirred solutions following abrupt changes of drug concentration. This model may be used for the interpretation of data obtained in neuropharmacological studies if (i) the diffusion coefficient of the molecules under investigation is constant within the excised tissue, (ii) drug molecules are diffusing only in the extracellular space (ECS) and are not bound by the tissue, (iii) drug molecules diffuse mainly within one dimension, (iv) the drug concentration in the bath is changed within 5 s, and (v) the b…
The Properdin System: Composition and Function
1978
. This article summarizes the physicochemical data on the factors which compose the properdin system in guinea pig and man. The following other topics are discussed: (1) Activation of the properdin system; (2) Formation of the initiating and amplification C3 convertases; (3) Formation of the C5 convertase, and (4) Regulatory control mechanisms of the properdin system.
3,4-trans-4-Aryl-3-(1-pyridinio)-1,2,3,4-tetrahydropyridine-6-thiolates—new group of potential cardiotonic drugs
2005
Abstract 3,4- trans -4-Aryl-3-(1-pyridinio)-1,2,3,4-tetrahydropyridine-6-thiolates 6 – 11 were prepared by a Michael reaction of N -acetonylpyridinium chloride with 3-aryl-2-cyanothioacrylamides or by a one-pot three-carbon condensation of N -acetonylpyridinium chloride, aromatic aldehyde and 2-cyanothioacetamide, and their cardiotonic properties were studied. 3,4- trans -5-cyano-2-hydroxy-2-methyl-4-(3-nitrophenyl)-3-(1-pyridinio)-1,2,3,4-tetrahydropyridine-6-thiolate 8 was considered as a lead compound in this series since it in vitro experiments (spontaneously beating rat atria) showed a cardiotonic activity similar to that of milrinone 2 , however compound 8 induced activity at lover co…
The lack of the effect of DA-1 and DA-2 dopamine agonists on the isolated guinea-pig atria.
1987
1 The effects of dopamine and both DA-1 and DA-2 dopamine receptor agonists have been studied on the contractile force of electrically driven guinea-pig left atria and frequency of spontaneously beating right atria. 2 Pretreatment of animals with reserpine caused a parallel rightward shift of the concentration-response curve to dopamine of either preparation. 3 Propranolol, but not domperidone, shifted to the right the dose-response curve for the positive inotropic and chronotropic effects of dopamine. 4 Neither apomorphine, fenoldopam, bromocriptine nor piribedil had effects on the frequency and contractile force of the isolated guinea-pig atria. 5 These results suggest that DA-1 and DA-2 …
Study on the histamine-like activity of guanfacine
1990
Abstract The effects of guanfacine have been studied on guinea-pig isolated atria and diethylstilboestrol-treated rat isolated uterus to determine whether it possesses histamine-like activity. Guanfacine produced a concentration-dependent negative chronotropic effect which was not modified by ranitidine (0.1 μM). In rat isolated uterus contracted by KCl, clonidine (5–5000 μM) produced concentration-dependent relaxation which was blocked by ranitidine (0.1 μM), but guanfacine only produced relaxation at high concentrations (100–1000 μM), and this was not affected by ranitidine (0.1 μM). It is concluded that guanfacine, unlike clonidine, does not produce effects due to activation of H2-recept…
Effects of the Phosphodiesterase Inhibitor Enoximone on the Autonomic Innervation of the Isolated Heart
1989
Enoximone is a selective inhibitor of a low Km, cyclic AMP-specific type of phosphodiesterase (PDE III). In guinea pig and chicken atria, enoximone (0.1-100 mumol/L) caused a weak increase in the force of contraction. The heart rate was slightly enhanced or was unchanged (chicken). Enoximone (30 mumol/L) also failed to shift the concentration-response curves for the positive inotropic and chronotropic effects of norepinephrine in guinea pig atria. Under almost the same conditions, enoximone and the nonselective PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX) markedly potentiated the forskolin-induced mobilization of choline from phospholipids. The concentrations of IBMX (100 mumol/L) and o…
Core Histones Are Glutaminyl Substrates for Tissue Transglutaminase
1996
Chicken erythrocyte core histones are glutaminyl substrates in the transglutaminase (TGase) reaction with monodansylcadaverine (DNC) as donor amine. The modification is very fast when compared with that of many native substrates of TGase. Out of the 18 glutamines of the four histones, nine (namely glutamine 95 of H2B; glutamines 5, 19, and 125 of H3; glutamines 27 and 93 of H4; and glutamines 24, 104, and 112 of H2A) are the amine acceptors in free histones. The use of Gln112 of H2A requires a temperature-dependent partial unfolding of the histone, showing that structural determinants are decisive for the glutamine specificity. The structures of H2A and H2B do not appreciably change upon mo…
Structural characterisation of the natural membrane-bound state of melittin: a fluorescence study of a dansylated analogue
1997
Abstract The binding of a dansylated analogue of melittin (DNC–melittin) to natural membranes is described. The cytolytic peptide from honey bee venom melittin was enzymatically labelled in its glutamine-25 with the fluorescent probe monodansylcadaverine using guinea pig liver transglutaminase. The labelled peptide was characterised functionally in cytolytic assays, and spectroscopically by circular dichroism and fluorescence. The behaviour of DNC–melittin was, in all respects, indistinguishable from that of the naturally occurring peptide. We used resonance energy transfer to measure the state of aggregation of melittin on the membrane plane in synthetic and natural lipid bilayers. When bo…
Effect of Ultraviolet Irradiation on Biosynthesis of Dna in Guinea-Pig Skin in Vivo
1974
The molecular and metabolic alterations preceding the clinical manifestation of a photobiologic process, the erythematous or sunburn reaction, were investigated in mammalian skin in vivo. The effect of a moderate (2.5–3 times the minimal erythema dose [MED]) and a large (6–8 times MED) dose of ultraviolet radiation (290–320 nm) on the incorporation of [ Me - 3 H]-thymidine into epidermal cell DNA of guinea pigs was studied. The epilated half of the back of each animal was irradiated with various doses of ultraviolet light, and the other half served as the nonirradiated control. The amount of intraperitoneally injected [ Me - 3 H]-thymidine incorporated into the DNA was determined by the iso…
Cloning and tissue expression of two cDNAs encoding the peroxisomal 2-enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase in the guinea pig liver
1996
Abstract The 2-enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase (HD) is the second enzyme of the peroxisomal β-oxidation pathway. In human and rat, only one HD mRNA has been so far detected in the liver. This paper reports for the first time in a mammal species, the guinea pig, the cloning and sequencing of two cDNAs encoding an HD. The 3,274 nucleotide-cDNA is a strictly identical but longer copy of the 2,494 nucleotide-form. A 2,178 by-open reading frame encodes a protein of 726 amino acids ( M r 79.3 kDa) with the peroxisomal-targeting signal (tripeptide SKL) at the carboxyterminus. Northern blot analysis of HD mRNA identified three mRNAs of respective sizes 3.5, 2.6 and 1.6 kb in the…