Search results for "Guinea"
showing 10 items of 412 documents
Comparison of anti-transglutaminase ELISAs and an anti-endomysial antibody assay in the diagnosis of celiac disease: A prospective study
2002
Abstract Background: Most studies of anti-transglutaminase (anti-tTG) assays have considered preselected groups of patients. This study compared the sensitivity, specificity, and predictive value of an immunofluorescence method for anti-endomysial antibodies (EmAs) and two anti-tTG ELISAs, one using guinea pig tTG (gp-tTG) and the other human tTG (h-tTG) as antigen, in consecutive patients investigated for suspected celiac disease (CD). Methods: We studied 207 consecutive patients (99 men, 108 women; age range, 17–84 years) who underwent intestinal biopsy for suspected CD. Patients presented with one or more of the following: weight loss, anemia, chronic diarrhea, abdominal pain, dyspepsia,…
Investigation into the role of phosphodiesterase IV in bronchorelaxation, including studies with human bronchus.
1993
1. We have investigated the role of cyclic nucleotide phosphodiesterase IV (PDE IV) in the relaxation of human bronchus and guinea-pig trachea in vitro and in guinea-pigs in vivo. 2. Functional studies showed that the selective PDE IV inhibitors, rolipram and denbufylline, relaxed human and guinea-pig preparations in vitro. 3. Two clinically used xanthine non-selective PDE inhibitors, theophylline and pentoxifylline, were also effective in these preparations, but were much less potent than the selective agents used. 4. The rank order of potency for the four PDE inhibitors in both species was similar. 5. Biochemical studies indicated that PDE IV was the major PDE isoform present in the human…
Influence of Duration of Experiment on Rate of Uptake of Radioactive Potassium in Smooth Muscle
1963
THE rates of uptake and loss of radioactive tracers by excitable tissues can often be described by a function involving one exponential term1–3, but over relatively long periods deviations have been observed from such a simple course4–7. The rates of exchange towards the end of such periods are commonly slower than would be predicted from the initial rates and two general causes for this behaviour have been suggested: either the rates are, in fact, diminishing during the course of an experiment or the tissue is not behaving uniformly. This latter possibility has been extensively investigated1,8–15, because biological material shows an obvious lack of uniformity, and because deviations from …
Histaprodifens: synthesis, pharmacological in vitro evaluation, and molecular modeling of a new class of highly active and selective histamine H(1)-r…
2000
A new class of histamine analogues characterized by a 3, 3-diphenylpropyl substituent at the 2-position of the imidazole nucleus has been prepared outgoing from 4,4-diphenylbutyronitrile (4b) via cyclization of the corresponding methyl imidate 5b with 2-oxo-4-phthalimido-1-butyl acetate or 2-oxo-1,4-butandiol in liquid ammonia, followed by standard reactions. The title compounds displayed partial agonism on contractile H(1) receptors of the guinea-pig ileum and endothelium-denuded aorta, respectively, except 10 (histaprodifen; 2-[2-(3, 3-diphenylpropyl)-1H-imidazol-4-yl]ethanamine) which was a full agonist in the ileum assay. While 10 was equipotent with histamine (1), methylhistaprodifen (…
Effects of dantrolene on the responses to methylxanthines in the isolated guinea-pig trachea.
1991
The effect of dantrolene on the responses to methylxanthines (caffeine and theophylline) and a beta-adrenoceptor agonist (salbutamol) was studied in isolated guinea-pig trachea. Caffeine and theophylline (1 microM-10 mM) and salbutamol (1 nM-10 microM) produced concentration-dependent relaxation of spontaneous and stimulated (acetylcholine 1 mM) tone. Responses to high concentrations (10 mM) of caffeine and theophylline added to tracheal strips either unstimulated (spontaneous tone) or indomethacin (2.8 microM)-treated were reversed to contractions in the presence of dantrolene (3 microM-0.3 mM). This effect was not observed for salbutamol or when relaxant responses to the agonists were gen…
DIFFERENT ABILITY OF TRIFLUOPERAZINE TO INHIBIT AGONIST-INDUCED CONTRACTION OF LUNG PARENCHYMA STRIPS FROM CONTROL AND SENSITIZED GUINEA-PIGS
1988
Abstract There is increasing interest in the therapeutic potential of calcium antagonists in asthma. Among them the use of calmodulin antagonists deserves consideration. In the present work the effect of trifluoperazine on contractions generated by different mechanisms (CaCl2, KCl, acetylcholine, histamine and 5-hydroxytryptamine) in lung parenchyma strip isolated from control and actively sensitized guinea-pigs has been studied. Trifluoperazine produced both in unsensitized and sensitized lung strips, a concentration-dependent, right, downward displacement of the concentration-response curves to the agonists used, although the sensitization procedure resulted in a potentiation in the abili…
Modulation by 5-HT3 and 5-HT4 receptors of the release of 5-hydroxytryptamine from the guinea-pig small intestine.
1993
The effects of agonists and antagonists of 5-hydroxytryptamine (5-HT) receptors on the release of endogenous 5-HT from enterochromaffin cells were studied in the vascularly perfused isolated guinea-pig small intestine. The experiments were done in the presence of tetrodotoxin in order to exclude a neuronally mediated influence on 5-HT release. The 5-HT3 receptor agonist 2-methyl-5-HT increased 5-HT release, and this effect was antagonized by 1 nmol/l tropisetron. Nanomolar concentrations of tropisetron, MDL 72,222 and granisetron decreased 5-HT release. Ondansetron (0.1 and 1 mumol/l) did not modify 5-HT release. 5-Methoxytryptamine, BIMU8 and cisapride concentration-dependently inhibited 5…
Glycopyrronium bromide blocks differentially responses mediated by muscarinic receptor subtypes.
1993
To analyse the potency of glycopyrronium bromide in blocking responses mediated via subtypes of muscarinic receptors in vitro, we tried to determine its equilibrium dissociation constants at prejunctional muscarinic receptors inhibiting the twitch response of rabbit vas deferens (presumed M1 type), at M2 (paced at left atria), M3 (guinea pig ileum) muscarinic receptor subtypes and at the muscarinic receptor of the rabbit iris sphincter (not M1-M4, not m5). Glycopyrronium bromide shifted to the right the curve for inhibition of the twitch response induced by the agonist McN-A-343, and the methacholine-induced curves for inhibition of rat atrial contraction, and for tonic contraction of guine…
Tachykinin NK(2) receptors facilitate acetylcholine release from guinea-pig isolated trachea.
2000
The release of newly synthesised [3H]acetylcholine was evoked by electrical field stimulation (5 Hz, 600 pulses) of epithelium-deprived guinea-pig trachea strips after sensory neuropeptides depletion with 3 microM capsaicin. The selective tachykinin NK(2) receptor agonist [betaAla(8)]neurokinin A-(4-10) increased in a concentration-dependent manner the electrically-induced release of [3H]acetylcholine. The facilitatory effect was antagonised by the selective non-peptide tachykinin NK(2) receptor antagonist, SR 48968 (apparent pK(B) 8.9). The tachykinin NK(1) and NK(3) receptor agonists substance P methyl ester and senktide (both 10 and 100 nM), respectively, did not affect the evoked releas…
Crystallization of the altitude adapted hemoglobin of guinea pig.
2009
Hemoglobin is the versatile oxygen carrier in the blood of vertebrates and a key factor for adaptation to live in high altitudes. Several structural changes are known to account for increased oxygen affinity in hemoglobin of altitude adapted animals such as llama and barheaded goose. Guinea pigs are adapted to live in high altitudes in the Andes and consequently their hemoglobin has an increased oxygen affinity. However, the structural changes responsible for the adaptation of guinea pig hemoglobin are unknown. Here we report the crystallization of guinea pig hemoglobin in the presence of 2.6 M ammonium sulfate and a preliminary analysis of the crystals. Crystals diffract up to a resolution…