401
|
Resink TJ, Scott-Burden T, Weber E, Bühler FR. Phorbol ester promotes a sustained down-regulation of endothelin receptors and cellular responses to endothelin in human vascular smooth muscle cells. Biochem Biophys Res Commun 1990; 166:1213-9. [PMID: 2154974 DOI: 10.1016/0006-291x(90)90995-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The effect of phorbol ester pretreatment of human vascular smooth muscle cells (hVSMC) was studied with respect to regulation of endothelin (ET)-receptor binding and cellular responses to ET. The capacity of hVSMC to bind ET was decreased (by approximately 50% at maximum) after phorbol exposure, and this reductive effect was both rapid (t 1/2 approximately 10 min.) and sustained (for up to 24 hrs. of chronic phorbol exposure). Phorbol pretreatment inhibited both inositol phosphate and diacylclycerol production responses of hVSMC to ET in a manner that was time-dependent and sustained. Phorbol pretreatment also produced a persistent reduction in the ability of ET to release isotopically-labelled arachidonic and/or its metabolites from hVSMC, but importantly ionomycin-stimulated release was similarly negatively affected. Furthermore, ET-induced accumulation of the phospholipase A2/phospholipase B-derived inositol phospholipid metabolite, glycerophosphoinositol, was not different between control and phorbol-treated hVMSC. The mechanism whereby phorbol exerts differential, but notably sustained inhibitory effects on ET-promoted signal transduction pathways are thus complex and illustrative of the selectivity of protein kinase C in regulating cellular responses.
Collapse
|
402
|
Weber E, Haas TA, Muller TH, Eisert WG, Hirsh J, Richardson M, Buchanan MR. Relationship between vessel wall 13-HODE synthesis and vessel wall thrombogenicity following injury: influence of salicylate and dipyridamole treatment. Thromb Res 1990; 57:383-92. [PMID: 2315893 DOI: 10.1016/0049-3848(90)90254-a] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We performed studies to determine the relationship between injured vessel wall thrombogenicity, vessel wall 13-hydroxyoctadecadienoic acid (13-HODE) synthesis and cAMP levels in rabbit treated with salicylate or dipyridamole. Injured vessel wall thrombogenicity was measured as the number of 3H-adenine labelled platelets adhered to the subendothelial basement membrane exposed by air injury in carotid arteries of rabbits treated orally with salicylate or dipyridamole. Vessel wall 13-HODE was measured by HPLC and vessel wall cAMP was measured by RIA. Vessel wall thrombogenicity was increased two-fold in rabbits treated with salicylate and decreased by half in rabbits treated with dipyridamole. The levels of vessel wall cAMP levels were correlated both with the plasma dipyridamole levels and increases in 13-HODE synthesis. cAMP levels were unaffected by salicylate treatment, but 13-HODE synthesis was decreased. We conclude that there is a significant relationship between vessel wall cAMP levels and 13-HODE synthesis, which in turn, influences subsequent vessel wall thrombogenicity.
Collapse
|
403
|
Lutz D, Kasparu H, Nowotny H, Weber E, Krieger O, Köller U, Tüchler H, Knapp W. Association of GP40/CD7+ acute myeloblastic leukemia and chromosome 5 aberrations. HAEMATOLOGY AND BLOOD TRANSFUSION 1990; 33:141-4. [PMID: 1691128 DOI: 10.1007/978-3-642-74643-7_26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
MESH Headings
- Antigens, CD7
- Antigens, Differentiation, T-Lymphocyte/analysis
- Antigens, Neoplasm/analysis
- Biomarkers, Tumor/analysis
- Chromosome Aberrations
- Chromosomes, Human, Pair 5/ultrastructure
- DNA Nucleotidylexotransferase/analysis
- Humans
- Leukemia, Myeloid, Acute/classification
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/immunology
- Leukemia, Myelomonocytic, Acute/genetics
- Leukemia, Myelomonocytic, Acute/immunology
- Membrane Glycoproteins/analysis
- Neoplasm Proteins/analysis
- Phenotype
Collapse
|
404
|
Jacubeit T, Drisch D, Weber E. Risk factors as reflected by an intensive drug monitoring system. AGENTS AND ACTIONS. SUPPLEMENTS 1990; 29:117-25. [PMID: 2316432 DOI: 10.1007/978-3-0348-7292-8_13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Age and gender are often suspected to be risk factors predisposing to ADRs. Therefore the data obtained by the Heidelberg Intensive Drug Monitoring System were analysed for possible correlations between these two variables and the incidence of ADRs. Based on the medical records comprising the time period between 1980 and 1987 information was available on 70,500 admissions to the Heidelberg University Hospital, Department of Medicine. Age, gender, number of prescriptions and ADRs were analysed. The percentage of patients affected by ADRs rises with advancing age; however the number of prescribed drugs also increases. When the incidence of ADRs in various age groups was analysed in relation to prescription data, no effect of age could be found. In contrast there was a linear correlation between the overall incidence of ADRs (independent of age) and the number of prescriptions per patient (per single admission). These results clearly document that age does not seem to be relevant to the incidence of ADRs, but that the risk is related to the number of drugs prescribed to a particular patient.
Collapse
|
405
|
Dianzumba SB, DiPette D, Joyner CR, Cornman C, Townsend R, Mauro K, Weber E, Theobald T. Left ventricular filling in hypertensive blacks and whites following adrenergic blockade. Am J Hypertens 1990; 3:48-51. [PMID: 2405883 DOI: 10.1093/ajh/3.1.48] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Left ventricular diastolic filling was investigated in 12 black and 15 white subjects before and after double-blinded randomized treatment of mild to moderate hypertension with combined alpha- and beta-adrenergic receptor blockade (labetalol) and beta-blockade alone (atenolol). At baseline (off medication), both groups were similar for age (46 +/- 8 years v 48 +/- 12 years), mean blood pressure (121 +/- 8 mm Hg v 115 +/- 8 mm Hg), left ventricular dimensions, left ventricular mass index (118 +/- 24 g/m2 v 113 +/- 13 g/m2), and left ventricular filling as reflected by transmitral flow velocity ratio A/E (0.97 +/- 0.33 v 0.92 +/- 0.19, normal age-matched control A/E ratio is 0.64 +/- 14). There were 6 blacks and 6 whites in the labetalol group; 6 blacks and 9 whites in the atenolol group. At six weeks of treatment, whites in the labetalol group showed a significantly greater drop in mean blood pressure (114 +/- 7/102 +/- 11, P less than .007 v 123 +/- 9/114 +/- 11, P = NS) and correspondingly greater improvement in A/E ratio (1.04 +/- 0.14/0.74 +/- 0.23, P less than .024 v 1.02 +/- 0.23/0.89 +/- 0.16, P = NS). However, this difference was no longer significant when controlling for age and blood pressure level. In the atenolol group, whites showed a significant increase in the rapid filling phase velocity E, while late filling phase velocity A significantly dropped only in blacks, without significant improvement in A/E ratio in either subgroup. In conclusion, greater improvement in left ventricular filling is seen with combined alpha-beta-blockade than beta-blockade alone.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
406
|
Kruse W, Eggert-Kruse W, Rampmaier J, Runnebaum B, Weber E. Compliance with short-term high-dose ethinyl oestradiol in young patients with primary infertility. New insights from the use of electronic devices. AGENTS AND ACTIONS. SUPPLEMENTS 1990; 29:105-15. [PMID: 2316431 DOI: 10.1007/978-3-0348-7292-8_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The objective of the study was to investigate patient compliance with ethinyl oestradiol therapy. Medication was prescribed to be taken in 20-micrograms doses four times daily for seven days. Oestrogens are prescribed for standardization of the cervical mucus before the sperm cervical-mucus penetration test (SCMPT) is performed. Relation of drug compliance with adverse drug reactions reported by the patients. The methodology used in this study was continual microprocessor-based monitoring by means of the Medication Event Monitoring System, MEMSTM. Adverse drug reactions were recorded by means of standardized interviews. Investigations were carried out on thirty female patients, mean age: 28.8 years (range 21 to 36 years), with primary infertility, mean duration of infertility: 3.9 years (range 9 months to 8 years). The results showed that individual patients' compliance was remarkably variable, ranging from 14.3% up to 136%. The average compliance was 65%. Less than 30% of the prescribed doses were taken on schedule. Administration of oestrogens was effective in all but one patient. High cervical indices were documented irrespectively of the dose taken. In answer to the questionnaire, 24 out of 30 women reported side effects, of which 79% were rated by the patients as being mild. The lower the drug compliance was, the more adverse reactions were reported. In patients who took more than 65% of the drug, this inverse relationship was statistically significant (r = -0.71, p = less than 0.01). Our conclusion is that the empirically fixed daily dose of 80 micrograms of ethinyl oestradiol for seven days appeared to be too high in regard of the observed dose response, i.e. cervical mucus quality. A dose finding study, including compliance monitoring, seems to be reasonable. Within further studies, a simpler dosage regimen should also be taken into account. The observed association between patients' reports of adverse effects and drug compliance deserves further investigation.
Collapse
|
407
|
Reddy PJ, Ravichandran V, Chacko KK, Weber E, Saenger W. Structure of the 2,5,8-trithia[9](2,6)pyridinophane–silver nitrate complex (1:1). Acta Crystallogr C 1989. [DOI: 10.1107/s0108270189003574] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
408
|
|
409
|
Ding RW, Kolbe K, Merz B, de Vries J, Weber E, Benet LZ. Pharmacokinetics of nicotinic acid-salicylic acid interaction. Clin Pharmacol Ther 1989; 46:642-7. [PMID: 2598568 DOI: 10.1038/clpt.1989.200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Both nicotinic acid and salicylic acid undergo glycine conjugation in human beings. Competitive inhibition may therefore be possible when these substances are used concomitantly in patients with hyperlipidemic disorders. The aim of this study was to determine, in six healthy subjects, whether nicotinic acid steady-state levels and total clearance are affected by concomitant aspirin administration. Steady-state nicotinic acid concentrations were obtained in all six volunteers by infusion of nicotinic acid solutions at constant rates (0.075 to 0.100 mg/kg/min) for 6 hours; aspirin (1 gm) was administered orally 120 minutes after the beginning of the infusion of nicotinic acid. Plasma samples were analyzed for nicotinic acid, nicotinuric acid, and salicylic acid. After aspirin administration an immediate marked decrease of nicotinuric acid levels could be observed in all six volunteers, whereas nicotinic acid concentrations increased. We hypothesize that salicylic acid causes a concentration-dependent decrease of total nicotinic acid clearance that results in the saturation (and effective elimination) of the nicotinuric acid conjugation pathway.
Collapse
|
410
|
Krieger O, Bernhart M, Fiedler E, Kasparu H, Weber E, Lutz D. Preliminary results of an induction combination regimen including fractionated anthracycline. Bone Marrow Transplant 1989; 4 Suppl 3:66. [PMID: 2627610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
411
|
De Vries JX, Walter-Sack I, Ittensohn A, Weber E. The isolation, identification and structure of a new hydroxylated metabolite of benzbromarone in man. Xenobiotica 1989; 19:1461-70. [PMID: 2618093 DOI: 10.3109/00498258909043196] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
1. The metabolic fate of the uricosuric drug, benzbromarone, in man was reinvestigated. Plasma and urine samples obtained from healthy subjects after administration of a single oral dose of 100 mg were analysed by h.p.l.c. and g.l.c.-mass spectrometry; bromobenzarone and benzarone, previously assumed to be the debrominated metabolites of benzbromarone, were not detectable. 2. Instead, two metabolites (M1 and M2) were present in plasma samples, which had plasma elimination rates lower than those of the parent drug. 3. One of the metabolites (M1) was identified as 1'-hydroxy-benzbromarone using g.l.c.-mass spectrometric analysis of trimethylsilylated and methylated extracts. Chromatographic and spectroscopic data for this metabolite were identical to those of the synthetic compound.
Collapse
|
412
|
Simank HG, Simon M, Bode C, Zimmermann R, Kübler W, Weber E. Clinical usefulness of D-dimer: evaluation during fibrinolytic treatment of venous thrombosis or myocardial infarction. Thromb Res 1989; 56:541-6. [PMID: 2609291 DOI: 10.1016/0049-3848(89)90238-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
413
|
Kavanaugh MP, Parker J, Bobker DH, Keana JF, Weber E. Solubilization and characterization of sigma-receptors from guinea pig brain membranes. J Neurochem 1989; 53:1575-80. [PMID: 2552016 DOI: 10.1111/j.1471-4159.1989.tb08554.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The sigma-receptor, a distinct binding site in brain tissue that may mediate some of the psychotomimetic properties of benzomorphan opiates and phencyclidine, has been solubilized using the ionic detergent sodium cholate. Binding assays were performed with the solubilized receptor using vacuum filtration over polyethyleneimine-treated glass fiber filters. The pharmacological specificity of the solubilized binding site for sigma-receptor ligands is nearly identical to the membrane-bound form of the receptor, with the order of potencies for displacement of the selective sigma-ligand [3H]di-o-tolylguanidine ([3H]DTG) closely correlated. The stereoselectivity for (+)-benzomorphan opiate enantiomers was retained by the solubilized receptor. The soluble receptor retained high affinity for binding of [3H]DTG (KD = 28 +/- 0.5 nM) and (+)-[3H]3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [(+)-[3H]3-PPP] (KD = 36 +/- 2 nM). Photoaffinity labeling of the solubilized receptor by [3H]p-azido-DTG, a sigma-selective photoaffinity label, resulted in labeling of a 29-kilodalton polypeptide identical in size to that labeled in intact membranes. Estimation of the Stokes radius of the [3H]DTG binding site was obtained by Sepharose CL-6B chromatography in the presence of 20 mM cholate and calculated to be 8.7 nm. This value was identical to the molecular size found for the binding sites of the sigma-selective ligands (+)-[3H]3-PPP and (+)-[3H]SKF-10,047, supporting the hypothesis that all three ligands bind to the same macromolecular complex.
Collapse
|
414
|
Walter-Sack IE, de Vries JX, Nickel B, Stenzhorn G, Weber E. The influence of different formula diets and different pharmaceutical formulations on the systemic availability of paracetamol, gallbladder size, and plasma glucose. INTERNATIONAL JOURNAL OF CLINICAL PHARMACOLOGY, THERAPY, AND TOXICOLOGY 1989; 27:544-50. [PMID: 2613389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The influence of two liquid formula diets on the systemic availability of paracetamol was investigated in 12 healthy normal volunteers using a liquid and a solid paracetamol dosage form. The diets contained the same balanced amounts, but different patterns of nutrients and different amounts of dietary fiber. Plasma glucose and gallbladder response to the standard meal were used as indicators of gastric emptying. Paracetamol plasma concentrations following application of the liquid dosage form also served as a marker for the gastroduodenal transport of liquid gastric contents. For the liquid dosage form, the plasma concentration time curves did not vary with diet composition. However, with the tablets, a differential effect was observed. Following coingestion with the fiber depleted diet, the rate of systemic availability was reduced more than with the liquid preparation. A further delay was obvious, when the tablets were combined with the meal enriched in dietary fiber. Plasma glucose and gallbladder response did not vary with diet composition. Variations of gastric emptying are unlikely to account for the variability of food effects. Consequently our results illustrate that an interaction of certain meal components with a particular drug dosage form determines the rate of intragastric release of the active compound. This could be shown due to a high standardization of nutrition by using liquid formula diets. Because of the variation of drug release, paracetamol cannot be used as a marker of gastric emptying without taking into account the vehicle necessary for drug application. In contrast to previous studies, our data provide evidence that even balanced test meals retard paracetamol absorption.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
415
|
Galligan JJ, Campbell BG, Kavanaugh MP, Weber E, North RA. 1,3-Di(2-tolyl)guanidine blocks nicotinic response in guinea pig myenteric neurons. J Pharmacol Exp Ther 1989; 251:169-74. [PMID: 2552073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Ditolylguanidine (DTG) is a ligand which binds with high affinity to neuronal sigma receptors. Activation of sigma receptors inhibits the release of acetylcholine (ACh) from guinea pig ileum myenteric plexus preparations. A study was therefore undertaken to investigate the action of sigma receptor ligands on single neurons. Nicotinic responses to locally applied ACh onto single neurons of the guinea pig ileum myenteric plexus were studied using intracellular recording techniques. DTG and (+)-SKF10047 (N-allylnormetazocine) produced a concentration-dependent suppression of the depolarization of enteric neurons evoked by ionophoresis of ACh. The EC50 values for DTG and (+)-SKF10047 were 4.7 and 3.8 microM, respectively, and were similar to that for hexamethonium (3.2 microM). The inhibition of the ACh-depolarization was not mediated at sigma receptors because (-)SKF10047 and Bridge-DPG (2-imino-1,3H-dibenzo[d,f]-[1,3]-diazepine), which are inactive at sigma receptors, were as potent as DTG and (+)-SKF10047. DTG and hexamethonium (each at 1 microM) were more effective blockers of ACh-induced inward currents at a holding potential of -100 mV than at -40 mV. This voltage dependence is consistent with a channel blocking mechanism. DTG (10 microM) did not affect the depolarization (mediated by 5-HT3 receptors) induced by pressure application of 5-HT onto single neurons. DTG and Bridge-DPG inhibited contractures of the longitudinal muscle-myenteric plexus preparation elicited by dimethylphenylpiperazinium noncompetitively (EC50 values were 8.0 and 12.3 microM, respectively) whereas DTG but not Bridge-DPG inhibited 5-HT-induced contractions of the longitudinal muscle-myenteric plexus noncompetitively.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
416
|
Campbell BG, Scherz MW, Keana JF, Weber E. Sigma receptors regulate contractions of the guinea pig ileum longitudinal muscle/myenteric plexus preparation elicited by both electrical stimulation and exogenous serotonin. J Neurosci 1989; 9:3380-91. [PMID: 2552032 PMCID: PMC6569899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Sigma receptors are specific, highly localized binding sites in limbic and sensorimotor structures of the brain that interact with many psychotropic drugs. These agents include the psychotomimetic benzomorphan opiates, the psychotomimetic drug phencyclidine and its analogs, as well as numerous typical and atypical antipsychotics such as haloperidol, chlorpromazine, and the novel drugs BMY 14802 and rimcazole. So far, no physiological function has been assigned to these binding sites. We have synthesized a number of novel sigma receptor-active drugs derived from the selective sigma ligand N,N'-di(o-tolyl)guanidine (DTG). DTG and its congeners were found to inhibit contractions of the guinea pig ileal longitudinal muscle/myenteric plexus (LMMP) preparation evoked by electrical stimulation. In addition, the sigma ligands noncompetitively antagonized contractions of the LMMP preparation evoked by serotonin (5-HT). The 5-HT-evoked contractions were found to be largely due to 5-HT's activation of 5-HT3 receptors to release ACh. The activity of DTG congeners in inhibiting electrically or 5-HT-evoked contractions of the LMMP highly correlated with their potency to inhibit binding of both 3H-DTG and (+)3H-3-PPP [3(3-OH-phenyl)-N-(1-propyl)piperidine] to sigma receptors in guinea pig brain homogenates. Two DTG congeners that did not bind to sigma receptors also showed no activity in the bioassay. Many other (but not all) sigma receptor ligands showed a high correlation between their potency to inhibit electrically evoked contractions of the LMMP and their sigma receptor binding affinity. The benzomorphans (+)SKF 10,047 and (+)cyclazocine potentiated electrically evoked contractions of the LMMP. Sigma ligands also inhibited the contractions of the LMMP in the presence of the opiate antagonist naloxone and in preparations in which opioid receptors had been inactivated by treatment with the irreversible opiate antagonist beta-chlornaltrexamine. Control experiments suggested that the sigma ligands act via a neuronal mechanism to inhibit ACh release evoked by electrical stimulation or by stimulation with 5-HT. These results suggest that there are functional sigma receptors on cholinergic nerve terminals or within the myenteric plexus and that these receptors can inhibit stimulated ACh release through an opioid receptor-independent mechanism. However, sigma receptor activation in the ileum has the same effect on ACh release as activation of naloxone-sensitive opioid receptors. The LMMP may be an in vitro bioassay system for characterizing the mechanism of action of sigma receptors and for determining the biological efficacy of drugs known to bind to sigma receptors in radioligand binding assays.
Collapse
|
417
|
Walter-Sack I, Luckow V, Guserle R, Weber E. [The relative bioavailability of paracetamol following administration of solid and liquid oral preparations and rectal dosage forms]. ARZNEIMITTEL-FORSCHUNG 1989; 39:719-24. [PMID: 2775340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Determination of the Relative Bioavailability of Paracetamol Following Administration of Solid and Liquid Oral Preparations and Rectal Dosage Forms. The relative bioavailability of paracetamol from two solid and two liquid oral preparations and two rectal dosage forms, each containing 500 mg of the active ingredient, was investigated in 12 healthy male individuals. The plasma concentration-time curves of paracetamol following administration of the oral formulations were very similar; consequently there were only minor differences of the AUC0-12h (21.4, 21.9; 23.0, 22.8 micrograms.h/ml), cmax (8.8, 9.1; 10.0, 10.7 micrograms/ml), tmax (35, 25; 20, 19 min), and the terminal plasma elimination half-life t1/2 beta (2.95, 2.85; 2.86, 2.99 h) for the solid and the liquid test and reference preparations, respectively. The suppositories (test and reference formulation) differed from the oral dosage forms, but were comparable to each other with respect to AUC0-12h (18.2, 18.8 micrograms.h/ml), cmax (3.3, 3.5 micrograms/ml), tmax (1.6, 2.45 h), and t1/2 beta (3.55, 3.54 h). In all test preparations the 95% confidence limits for AUC0-12h completely were enclosed in the range of 80-120% relative bioavailability (independently of whether parametric or non-parametric statistical methods were applied); the limits for the oral formulations were quite narrow, thus indicating a highly consistent release of the active compound from the tablets as well as from the liquid dosage form. A comparison of the mean values of cmax by analysis of variance at the 80% probability level did not reveal any significant differences between the test and the corresponding reference formulations; based on non-parametric statistical methods, the 95% confidence limits for cmax were enclosed in the range of 70-130%.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
418
|
Weber E, von Segesser L, Turina M. [Isolated rupture of an iliacus aneurysm]. HELVETICA CHIRURGICA ACTA 1989; 56:275-8. [PMID: 2777612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A retrospective analysis of 23 patients with isolated iliac aneurysms is presented. The age of the 23 men ranged from 49 to 89 years (mean +/- SE: 72.2 +/- 8.4 y). All patients had pain, nineteen (83%) were in shock, in only 11 (48%) an abdominal mass was palpable. Fifteen (65%) of the aneurysms were located in the common iliac artery, 5 (22%) in the internal and 3 (13%) in the external iliac artery. Their diameter ranged from 3 to 12 cm (mean +/- SE: 7.8 +/- 2.6 cm). Resection with an unilateral graft interposition was done in 12 (52%), a Y-graft implanted in 8 (35%) and an endoaneurysmorrhaphy of the internal aneurysm performed in 2 patients. Early mortality was 22% and was not statistically different from the 28.6% mortality in ruptured abdominal aneurysm resections performed in the same time. Because of the substantial risk of rupture with high mortality elective operative intervention should be considered for isolated iliac aneurysms with a diameter more than 3 cm.
Collapse
|
419
|
Kavanaugh MP, Tester BA, Weber E. Interaction of MK-801 with the nicotinic acetylcholine receptor-associated ion channel from electroplax. Eur J Pharmacol 1989; 164:397-8. [PMID: 2474451 DOI: 10.1016/0014-2999(89)90487-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
420
|
Lester RA, Quarum ML, Parker JD, Weber E, Jahr CE. Interaction of 6-cyano-7-nitroquinoxaline-2,3-dione with the N-methyl-D-aspartate receptor-associated glycine binding site. Mol Pharmacol 1989; 35:565-70. [PMID: 2566902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The interaction of newly described antagonist of the non-NMDA glutamate receptor 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) with the glycine site of the NMDA receptor complex has been investigated. In whole-cell patch recordings from hippocampal neurons maintained in culture, currents induced by N-methyl-D-aspartate (NMDA) were dependent on extracellular glycine. Responses to both NMDA (30 microM) and kainate (20 microM) were reduced by CNQX (10-30 microM). The antagonism by CNQX of NMDA, but not kainate, receptor-mediated responses could be reversed by increasing the concentration of glycine in the external medium. Glycine concentration-response curves constructed in the presence of 30 microM NMDA were shifted to the right by CNQX, suggesting that CNQX was competing with glycine for the glycine binding site. However, even at high concentrations of glycine (300 microM) the maximal NMDA current obtained in the presence of CNQX (10-30 microM) was not restored to control levels. Because CNQX had no effect on responses produced by supramaximal concentrations of NMDA (500 microM) and glycine (300 microM), it is suggested that CNQX also interacts with the NMDA recognition site. The antagonism of currents induced by NMDA was not dependent on the membrane potential, and the rapid onset and offset of the block suggested that there was little or no use dependence. Radioligand binding experiments were performed using [3H]glycine to label the strychnine-insensitive glycine regulatory site of the NMDA receptor complex in guinea pig brain frontal cortex membranes. CNQX displaced [3H]glycine binding in a concentration-dependent manner (IC50 = 5.7 microM). Scatchard analysis of the inhibition showed a decrease in the affinity (increase in Kd) of [3H]glycine binding, but no change in the number of binding sites (Bmax) in the presence of 5 microM CNQX, suggesting a competitive interaction. These data provide evidence that CNQX antagonizes NMDA receptor-mediated responses by competing with glycine for a modulatory site associated with the NMDA receptor complex. Furthermore, the results indicate that CNQX may not be as selective an antagonist for non-NMDA receptors as initially described, although its selectivity will depend on the concentration of the NMDA receptor ligand and may be enhanced by increasing the extracellular concentration of glycine.
Collapse
|
421
|
Bannasch P, Enzmann H, Klimek F, Weber E, Zerban H. Significance of sequential cellular changes inside and outside foci of altered hepatocytes during hepatocarcinogenesis. Toxicol Pathol 1989; 17:617-28; discussion 629. [PMID: 2697940 DOI: 10.1177/0192623389017004107] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A variety of phenotypic cellular changes emerge in the liver of different species prior to the appearance of hepatocellular adenomas and carcinomas induced by carcinogenic agents (chemicals, radiation, hepadna viruses) or develop "spontaneously." Foci of altered hepatocytes have been studied most extensively in rats treated with chemical carcinogens; they are considered preneoplastic lesions and have been used in several laboratories as endpoints in carcinogenicity testing. The principles and problems of the morphological classification of foci of altered hepatocytes are presented. In addition to the 4 types of foci generally accepted (clear, acidophilic, basophilic and mixed cell foci), further subtypes (intermediate cell foci) or other types of foci, namely tigroid cell foci and amphophilic cell foci, have more recently been separated as distinct pathomorphological entities. Whereas the amphophilic foci might result from a modulation of clear and acidophilic cell foci, the tigroid cell foci apparently represent a stage in a separate cell lineage leading to hepatocellular adenomas. It remains open whether the tigroid cell foci may also progress to carcinomas. Extrafocal phenotypic changes of hepatocytes might also be involved in hepatocarcinogenesis. The cellular phenotypes within foci also depend strongly, among many other factors, on the dose and duration of the carcinogenic treatment. Cytomorphological, cytochemical, microbiochemical and stereological studies suggest that the predominant sequence of cellular changes during hepatocarcinogenesis leads from the clear and acidophilic cell foci storing glycogen in excess through mixed cell foci and nodules to basophilic cell populations prevailing in hepatocellular carcinomas. A multitude of metabolic aberrations is associated with the sequential cellular changes. Aberrations in carbohydrate metabolism are particularly prominent and might be causally related to the neoplastic transformation of the hepatocytes.
Collapse
|
422
|
Berg S, Weber E. Grundriss der Biologischen Statistik, 9 Aufl. Biometrics 1989. [DOI: 10.2307/2532062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
423
|
Van Ryn-McKenna J, Gray E, Weber E, Ofosu FA, Buchanan MR. Effects of sulfated polysaccharides on inhibition of thrombus formation initiated by different stimuli. Thromb Haemost 1989; 61:7-9. [PMID: 2473537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To test the possibility that different doses of heparin or other sulfated polysaccharides are required to inhibit thrombosis initiated by different stimuli, we compared the effects of heparin (HEP), pentosan polysulfate (SP54) and dermatan sulfate (DS) on the inhibition of thrombus formation induced by either I) tissue thromboplastin; II) thrombin; or III) factor Xa. Inhibition of thrombus formation induced by the stimuli was measured in a rabbit jugular vein hypercoagulation/stasis model. First, we determined the minimum dose of each sulfated polysaccharide which inhibited tissue thromboplastin-induced thrombus formation by approximately 75%, and then compared the relative effectiveness of this dose to prevent thrombus formation initiated with the other two stimuli. HEP and SP54 were less effective when thrombin was the thrombogenic stimulus, while DS was more effective. HEP was the most effective agent when factor Xa was the stimulus. We conclude that the antithrombotic effectiveness of a given dose of a sulfated polysaccharide may vary depending on the stimulus which initiates thrombus formation.
Collapse
|
424
|
Graybiel AM, Besson MJ, Weber E. Neuroleptic-sensitive binding sites in the nigrostriatal system: evidence for differential distribution of sigma sites in the substantia nigra, pars compacta of the cat. J Neurosci 1989; 9:326-38. [PMID: 2563278 PMCID: PMC6570010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The sigma site is a recently described binding site to which dextrorotary isomers of certain psychotomimetic benzomorphans bind specifically. Classical and nonclassical neuroleptics also have high affinity for the sigma site, including neuroleptics known to bind to the D2 dopamine receptor. The affinity of some D2-binding neuroleptics for the sigma site has raised the possibility that certain important effects of antipsychotic drugs may relate to the sigma site. Left unresolved has been the question of how these actions could relate to dopaminergic systems. To explore this issue we carried out an autoradiographic binding study of the distribution of the sigma-selective ligand 3H-DTG in the nigrostriatal system. We report here that haloperidol-displaceable 3H-DTG binding sites are densely concentrated in an anatomically discrete subdivision of the cat's substantia nigra pars compacta. This zone, identifiable as the striosome-projecting densocellular zone of the pars compacta, also shows heightened D2-related ligand binding but has reduced D1-related ligand binding relative to other parts of the nigral complex. This evidence suggests that sigma-mediated interactions with dopaminergic systems may occur in the substantia nigra pars compacta and that the functional effects of these interactions may influence the nigrostriatal projection to striosomes differentially.
Collapse
|
425
|
von Fournier D, Junkermann H, Stolz W, Weber E, Krapfe E, Fersizoglou N. Hormonal and non-hormonal medical therapy of benign breast disease. HORMONE RESEARCH 1989; 32 Suppl 1:28-31. [PMID: 2613213 DOI: 10.1159/000181304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mastopathy or nodular painful breast can be managed by several non-hormonal and hormonal treatments. Little data exist for effectiveness of the former. Whilst the hormonal treatments are considered to be very effective, their use can be limited by unpleasant side effects.
Collapse
|