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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 104 (1995), S. 207-217 
    ISSN: 1432-1106
    Keywords: Nitric oxide synthase ; Retina ; Immunohistochemistry ; Rat ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The distribution of neuronal nitric oxide synthase (NOS) immunoreactivity was examined in rat and rabbit retinas and was compared with the distribution of nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase reactivity and vasoactive intestinal peptide (VIP) immunoreactivity. An antibody raised against a C-terminal fragment of a cloned rat cerebellar NOS was used to localise NOS immunoreactivity. NOS immunoreactive cells were not detected in rat retinas at postnatal day 1 or 4, but were seen from postnatal day 7 onwards. NOS immunolabelling was seen in a small population of cells in the proximal inner nuclear layer. Most of the labelled cells had the position of amacrine cells and were seen to send processes into the inner plexiform layer. A few labelled cells were at times also seen in the ganglion cell layer, which are likely to correspond to displaced amacrine cells. The same NOS-labelling pattern was seen in rat and rabbit retinas. NADPH-diaphorase staining was observed in both species, in photoreceptor inner segments, in cells with the position of horizontal cells, in a subset of amacrine and displaced amacrine cells, in large cell bodies in the ganglion cell layer, in both plexiform layers, and in endothelium. Colocalisation of NOS immunoreactivity and NADPH-diaphorase staining was only observed among amacrine cells. However, not all NADPH-diaphorase-reactive amacrine cells were found to be NOS immunoreactive. VIP immunoreactivity was also localised in rat retinas in a subpopulation of amacrine cells, but no colocalisation of NOS and VIP immunoreactivity was observed. Our observations indicate that only amacrine cells contain the NOS form recognisable by the antibody used, and suggest that different isoforms of neuronal NOS may be present in retinal cells. Further, the onset of NOS expression in rat amacrine cells appears to occur independently of neuronal activity.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 8 (1975), S. 135-139 
    ISSN: 1432-1041
    Keywords: Proscillaridin A ; digoxin ; 86Rb-assay ; stabilityin vitro ; gastric juice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In anin vitro study, proscillardin A was found to be rapidly inactivated at low pH. More than 50 per cent of its activity, measured by86Rb assay, was lost after incubation for 15 minutes at pH 1 and 37° C. Compared with proscillaridin, the rate of inactivation of digoxin was lower in these experiments. The rapid inactivation of proscillaridin might be of clinical importance when treating patients with this glycoside.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 9 (1975), S. 39-47 
    ISSN: 1432-1041
    Keywords: Digoxin ; portal venous sampling ; absorption rate ; oral administration ; intrasigmoid administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of digoxin has been studied in fasting patients undergoing transumbilical, portal catheterization for diagnostic purposes. A purely aqueous solution was administered orally in 4 patients and in the sigmoid colon in 2 patients. Blood samples were taken simultaneously from the portal and a peripheral vein. Plasma digoxin concentrations were determined by radioimmunoassay. Digoxin appeared early in the blood after oral administration; the average peak of porto-peripheral concentration differences was at 18 min. After intrasigmoid administration, absorption was slower, and no distinct peaks were found. Calculation of the mean amounts absorbed showed that half the dose had been absorbed via the portal vein during 2 hours in the oral study and during 6 hours in the intrasigmoid test. Approximately 2/3 of the dose had been absorbed during 6 hours after oral dosing. The absorption rate was estimated taking into account the decreasing amount of drug left to be absorbed at different times. After oral administration, the mean peak rate was found to correspond to an absorption half-time of 0.78 h, which was more than 20 times faster than the rate after 6 h. The mean peak rate after intrasigmoid administration appeared to be about 1/3 of that after oral dosing. Physiological factors that might account for these differences in absorption rate are discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 8 (1975), S. 421-425 
    ISSN: 1432-1041
    Keywords: Proscillaridin ; enteric-coated tablets ; plasma levels ; urine excretion ; 86Rb-erythrocyte assay ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma concentration of proscillaridin was measured by a modified86Rd method during treatment with multiple doses of a commercial preparation of proscillaridin. Despite high doses, very low plasma levels were found, and there were only minute amounts of glycoside activity in urine and faeces. Administration of an enteric-coated proscillaridin preparation gave higher plasma levels, which raises the possibility of inactivation of the glycoside by acid gastric juice. The results suggest that proscillaridin has low biological availability when given orally, and that it is extensively metabolised in the body.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 9 (1975), S. 49-55 
    ISSN: 1432-1041
    Keywords: Digoxin ; serum concentration ; area comparison ; absorption ; radioimmunoassay ; infants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability of digoxin in solution was studied in 4 newborn infants with heart failure. Serum digoxin concentrations were determined by radioimmunoassay using125I. Bioavailability was estimated by comparison of the areas under the 8-h serum concentration curves (8-h AUC) after intravenous and oral administration of the glycoside. After oral administration of digoxin (1/4 of the digitalizing dose, 0.05 mg/kg bw), peak serum values of 2.3 – 4.4 ng/ml were reached within 30–90 min. After intravenous administration of the same amount of the glycoside, there was a rapid decrease in serum concentration during the first 2 h, and after about 4 h the serum concentration curves paralled those obtained after oral dosing. Based on within subject comparison of intravenous and oral 8-h AUC's, the mean bioavailability of digoxin was estimated to be 72 per cent (range 52 – 79 per cent). It was concluded that digoxin in solution, given to infants with mild to moderate heart failure, is well absorbed and biologically available to the same extent as in adults.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1041
    Keywords: enprofylline ; theophylline ; obstructive lung disease ; adenosine ; antagonism ; bronchodilatation ; plasma levels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Enprofylline, a xanthine-derivative shown experimentally to lack universal adenosine receptor antagonism, has been examined in patients with partly reversible, chronic, obstructive lung disease. Significant bronchodilation was produced by enprofylline 2 mg/kg, giving a peak plasma concentration of 3.0±0.6 µg/ml (mean ± SD). A dose of 2+4 mg/kg dilated the bronchi at least to the same extent as theophylline 9.2±0.9 mg/kg (plasma level 18.5±4.7 µg/ml). Neither at the low nor at the high dosage (2+4 mg/kg), giving plasma concentrations of 8.5±1.4 µg/ml, did enprofylline produce theophylline-like CNS effects, such as restlessness and tremor, but it did exhibit some of the innocuous side effects expected with xanthine derivatives, such as epigastric discomfort and headache. The comparison with theophylline was limited because different dosage forms had to be used (solution and tablets), which for example, resulted in different absorption rates. Nevertheless, the present findings indicate enprofylline to be a potent bronchodilator in patients with obstructive lung disease, suggesting that adenosine-receptor antagonism is not involved in the bronchodilator effects of xanthines.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 26 (1984), S. 711-717 
    ISSN: 1432-1041
    Keywords: fenflumizole ; thromboxane formation ; prostacylin formation ; platelet aggregation ; arachidonic acid ; healthy subjects ; blood clotting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Fenflumizole (2-(2,4-difluorophenyl)-4,5-bis(4-methoxyphenyl)imidazole), a new non-steroidal anti-inflammatory drug, was given to healthy subjects in single oral doses of 0.1, 1 and 2 mg/kg. The effect of the drug was followed for up to 8 h by repeated tests of arachidonic acid-induced platelet aggregation and was related to its concomitant plasma concentration. Fenflumizole reversibly inhibited platelet aggregation and the degree of inhibition was found to be linearly correlated with the log plasma concentration. There was depression of the formation of thromboxane B2 and 6-keto-prostaglandin F1α (the stable metabolites of thromboxane A2 and prostacyclin) in clotted whole blood measured by radioimmunoassay after fenflumizole 1 mg/kg. This effect was directly related to the concentration of the drug in plasma, the maximum effect being reached at fenflumizole concentrations 〉200 ng/ml. EC50-values for inhibition of the formation of thromboxane B2 and 6-keto-prostaglandin $$F_{1\alpha } $$ were approximately 20 and 40 ng/ml, respectively. The results suggest that orally administered fenflumizole is a potent inhibitor of platelet aggregation and prostanoid formation.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 267-271 
    ISSN: 1432-1041
    Keywords: Methylproscillaridin ; proscillaridin ; acid stability ; intestinal stability ; 86Rb-uptake inhibition assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The in vitro stability of methylproscillaridin has been compared with that of proscillaridin, the activities of the glycosides being assayed by the86Rbtechnique. After incubation in gastric juice at pH 1, 2, and 3, the activity half life of each glycoside was proportional to pH and was approximately 0.25 h, 2.5 h, and 25 h, respectively. The inactivation rate in pure hydrochloric acid at pH 2 did not differ from that in gastric juice of the same pH. The glycosides were stable in bile and enteric juice. In faeces, methylproscillaridin was stable and proscillaridin was inactivated with a half life of 32 h. It is concluded that the difference in biological availability between the two glycosides cannot be explained by differences in gastrointestinal stability.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 273-276 
    ISSN: 1432-1041
    Keywords: Proscillaridin ; oral administration ; biliary excretion ; proscillaridin conjugates ; enterohepatic recycling ; 86Rb-uptake inhibition assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A single oral dose of proscillaridin A (1.0–1.5 mg) was given to six patients with T-tube drainage of the common bile duct, and simultaneous samples of bile and plasma were collected at various times during the following 24 hours. Glycoside activity was assayed by the86Rb-uptake inhibition technique. Peak activities in plasma (mean 0.80 ng/ml) were attained after 0.5–2 h, and in bile (mean 6.9 ng/ml) after 1–4 h. Subsequently, proscillaridin activity in bile was less than 5 ng/ml for the remainder of the sampling period, and 10–100 times higher than that in plasma. Bile samples treated with β-glucuronidase and sulphatase showed 100–200 fold increase in glycoside activity. Deconjugation was also produced by treatment with enteric contents. The results suggest that conjugation of unchanged proscillaridin is a major metabolic route. After excretion in the bile, the conjugates may be split in the intestine and reabsorbed as active glycoside.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 485-486 
    ISSN: 1432-1041
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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