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  • Immunocytochemistry  (27)
  • bioavailability  (25)
  • Gas chromatography  (24)
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  • Blackwell Publishing Ltd
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  • Institute of Physics
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  • 1
    ISSN: 1432-2048
    Schlagwort(e): Immunocytochemistry ; (PEP carboxylase) ; PEP carboxylase ; Sorghum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The localization of phosphoenol pyruvate carboxylase (EC 4.1.1.3.1.) in the leaf cells of Sorghum vulgare was investigated by using three techniques: the conventional aqueous and non aqueous methods gave conflicting results; the immunocytochemical techniques clearly showed that the enzyme is predominantly located in the cytoplasm of mesophyll cells.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 251-258 
    ISSN: 1432-1041
    Schlagwort(e): medigoxin ; digoxin ; dissolution rate ; proportionality ; bioavailability ; prediction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary We compared our ability to predict the dose of medigoxin and of digoxin required to achieve a fixed serum concentration (the dose requirement) in 33 outpatients. Preliminary work supported the assumptions that the steady state glycoside concentration achieved was proportional to the daily dose given to an individual, and that the bioavailability of the different tablet presentations was similar for either glycoside. We were not able to predict the dose requirement from patient characteristics with any more certainty for medigoxin than for digoxin. Not only the between-patient variability in dose requirement, but also the within-patient variability, was similar for the two glycosides. However the digoxin used had a dissolution rate of over 90% in 1 h. When comparing medigoxin with digoxin of lower, or more variable dissolution rate, medigoxin may be preferable.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 53-55 
    ISSN: 1432-1041
    Schlagwort(e): digoxin ; bioavailability ; dose-dependency ; urinary excretion ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Nine healthy volunteers received single 0.25, 0.5, 1.0, 1.5, and 2.0 mg doses of oral digoxin tablets in random sequence on five occasions separated by at least 4 weeks. Urinary excretion of immunoassayable digoxin was determined from 8 consecutive 24 h urine samples collected after each dose. Mean values of cumulative urinary excretion of digoxin at the 5 doses were: 40.9, 35.6, 36.4, 34.1, and 33.5% of the dose (F=0.64; d. f.=4.32; N. S.). Mean values of urinary excretion half-life were: 2.48, 2.03, 2.20, 2.07, and 1.87 days (F=2.87; d. f.=4.32;p=0.05). Thus, the bioavailability of orally administered digoxin tablets in healthy volunteers is dose-independent over an 8-fold range of doses.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 287-292 
    ISSN: 1432-1041
    Schlagwort(e): diacetolol ; acebutolol ; bioavailability ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics and bioavailability of diacetolol, the principal metabolite of acebutolol, were studied in 6 healthy subjects. Plasma concentrations were determined following a single intravenous injection of diacetolol 100 mg and three oral doses of diacetolol 100, 400 and 800 mg, in random order. The average oral bioavailability of diacetolol was F: 0.302±0.052 (100 mg), 0.363±0.052 (400 mg) and 0.426±0.068 (800 mg); the differences are not significant. The mean plasma half-life of the terminal phase, 7.94±0.26 h after intravenous administration, was significantly higher than after oral administration 12.27±1.00 h (100 mg), 12.82±1.59 h (400 mg) and 13.05±1.22 h (800 mg) (p〈0.02 to 0.05); the mean urine half-lives of the terminal phase were not significantly different. Renal clearance of diacetolol 10.2±0.81·h−1 represented about two-thirds of total body clearance 15.9±1.21·h−1. The results suggest either a first-pass effect or incomplete absorption of diacetolol after oral administration.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 305-307 
    ISSN: 1432-1041
    Schlagwort(e): ketoprofen ; aluminium phosphate ; bioavailability ; antacid ; pharmacokinetics ; interaction study
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The purpose of this study was to determine whether a concomitant single dose of antacid (aluminium phosphate), or multiple doses of this antacid, administered prior to and with ketoprofen would alter the bioavailability of this non steroidal anti-inflammatory agent. The possible effects of aluminium phosphate were evaluated following administration of ketoprofen alone (Phase I), co-administration of antacid and ketoprofen (Phase II), and antacid for four days before administration of ketoprofen with co-administration on the day of the study (Phase III). There were no significant differences between treatment means for peak plasma concentration, time to peak plasma concentration, and area under the plasma concentration-time curve. The observed differences were due only to individual effects. The results indicate a lack of interaction between ketoprofen and the antacid aluminium phosphate (Phosphalugel)
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 359-365 
    ISSN: 1432-1041
    Schlagwort(e): tolfenamic acid ; anti-inflammatory agent ; human pharmacokinetics ; bioavailability ; intravenous administration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of tolfenamic acid, a new anti-inflammatory agent was studied in six healthy volunteers after an intravenous dose of 100 mg and oral doses of 100, 200, 400 and 800 mg. The disposition of intravenous tolfenamic acid could be described by two-compartment open model, with a central compartment volume (Vdc) of 5.6±0.31 (mean±SE), volume during β-phase (Vdβ) of 31±21, and a total elimination rate constant (k10) 1.6±0.1 h−1. The terminal elimination half-life was 2.5±0.6 h and the total plasma clearance 155±15 ml/min. The elimination occured principally by extrarenal mechanisms, the recovery of unchanged drug together with is glucuronide in urine averaging only 8.8% of the intravenous dose. The binding of tolfenamic acid to plasma proteins averaged 99.7%. The gastrointestinal absorption had a mean half-life of 1.7±0.1 h. Based on comparison of areas under the plasma concentration time-curves after intravenous and oral administration, the biovailability of tolfenamic acid capsules averaged 60%. The rate and extent of absorption and the rate of elimination of tolfenamic acid were independent of dose.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 65-72 
    ISSN: 1432-1041
    Schlagwort(e): tranexamic acid ; pharmacokinetics ; bioavailability ; oral absorption ; influence of food ; plasma clearance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Tranexamic acid 1 g was given intravenously to three healthy volunteers. Plasma concentrations decayed in three monoexponential phases. Most elimination took place during the first eight hours, giving an apparent elimination half-life of approximately two hours. Plasma clearance ranged between 110–116 ml/min. The urinary recovery of tranexamic acid exceeded 95% of the dose. Ten healthy volunteers were given tranexamic acid 2 g orally on an empty stomach, and together with a meal. Food had no influence on the absorption of tranexamic acid, as judged by comparison of the peak plasma concentration, the time required to reach the peak, the AUC from zero to six hours, and the urinary excretion data. The oral bioavailability of tranexamic acid, calculated from 24 h urinary excretion after oral and intravenous administration, was 34% of the dose.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 277-282 
    ISSN: 1432-1041
    Schlagwort(e): dexamethasone phosphate ; dexamethasone sulphate ; intravenous injection ; bioavailability ; pituitary-adreno-cortical suppression ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The metabolic fate and ACTH-supressant activity of two injectable dexamethasone esters, 21-phosphate and 21-sulphate, were studied in healthy men. After i.v. injection of 20 mg free steroid alcohol, dexamethasone phosphate was efficiently hydrolyzed to free dexamethasone, reaching its peak plasma concentration within 5 min. About 9% of the administered dose appeared in the urine as free dexamethasone. By contrast, virtually no free dexamethasone was found in plasma and urine after injection of dexamethasone sulphate. Pharmacokinetic analysis showed that dexamethasone sulphate had a shorter plasma half-life and a higher metabolic clearance rate than free dexamethasone. A larger fraction (60%) of dexamethasone sulphate was rapidly excreted unmetabolized in urine. The plasma cortisol level was significantly suppressed for more than 24 h after dexamethasone phosphate, while the plasma cortisol profile after dexamethasone sulphate merely showed physiological circadian variations. When the steroid esters were injected after pretreatment with metyrapone, a definite suppression of plasma ACTH was noted after dexamethasone phosphate, but again, dexamethasone sulphate was ineffective. These results cast serious doubt on the clinical value of dexamethasone sulphate as an injectable glucocorticoid, and critical reevaluation of this preparation is needed.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 465-471 
    ISSN: 1432-1041
    Schlagwort(e): metoclopramide ; pharmacokinetics ; bioavailability ; first-pass effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The time courses of plasma metoclopramide concentrations were followed in six subjects after oral and intravenous single dose administration. Plasma concentration-time data following i.v. administration in each subject were found to fit a two compartment model with a mean terminal half-life of 4.55 h±0.80 h and a mean distribution half-time of 0.35 h±0.09 h. Volumes of distribution were high (3.43±1.181 · kg−1), and clearances (0.53±0.191 · kg−1h−1) approached liver plasma flow. This suggests that metoclopramide occurs at higher concentrations in tissues than in plasma, and that its clearance is probably limited by liver blood flow rather than liver metabolic capacity. The post-absorption decline in metoclopramide plasma levels after oral administration was also biexponential in each subject. The terminal half-life was 5.17 h±0.98 h. Mean volume of distribution and mean clearance were similar to intravenous values (after adjustment for bioavailability). Oral absorption was rapid with peak plasma concentrations being reached at a mean time of 0.93 h. A mean bioavailability of 0.77 was calculated for the six subjects, and it was postulated that this incomplete availability is due to a first-pass effect. The inter-individual variation in the degree of ‘first-pass’ was considerable (0.47–1.14).
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 473-478 
    ISSN: 1432-1041
    Schlagwort(e): methadone ; bioavailability ; pharmacokinetics ; single dose ; stable isotope technique ; two compartment model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The disposition of methadone was studied in eight opiate dependent subjects during detoxification. Plasma concentrations were determined by mass fragmentography for 48 hours after administration of methadone 20 mg as tablets and simultaneous intravenous injection of deuterium-labelled methadone 20 mg. Pharmacokinetic parameters were calculated for the intravenous dose assuming a two compartment open model. Bioavailability was determined by comparing the areas under the plasma concentration versus time curves of unlabelled and labelled methadone. The beta-phase plasma half-lives varied five-fold, with a range from 8.5 to 47 h. The apparent volumes of distribution varied from 2.1 to 5.61/kg. Five patients had a bioavailability exceeding 90%, and three had lower bioavailabilities of between 41 and 76%. The unlabelled and labelled drug appeared to be pharmacokinetically equivalent. The data show that for a majority of these subjects the bioavailability was higher than 45%, the previously reported value. The marked individual variation in methadone pharmacodynamics and kinetics, and the possibilities both of cellular and methabolic tolerance, require an individually optimized dosage regimen.
    Materialart: Digitale Medien
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  • 11
    ISSN: 1432-1041
    Schlagwort(e): verapamil ; pharmacokinetics ; bioavailability ; hepatic first-pass metabolism ; stable isotopes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Following i. v. administration, the plasma concentration-time curve of verapamil could best be described by either a mono- or biexponential equation. Total plasma clearance (1.26 l/min) approached liver blood flow (1.5 l/min), so it can be concluded that its clearance is liver blood flow-dependent. Although absorption was almost complete after oral administration, absolute bioavailability (20%) was low, due to extensive hepatic first-pass metabolism. The approach using stable isotope-labelled and unlabelled drug permits simultaneous administration by the intravascular and extravascular routes, thus allowing determination of absolute bioavailability in a single experiment.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 149-155 
    ISSN: 1432-1041
    Schlagwort(e): proxyphylline ; asthma ; pharmacokinetics ; bioavailability ; healthy adults ; theophylline derivative
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Serum concentrations and urinary excretion of proxyphylline have been measured in five healthy adults after intravenous (29 µmol/kg), single oral (21 µmol/kg) and multiple oral (21 µmol/kg three times a day) doses to produce steady state. The mean peak time after oral administration was 29 min. The mean fraction absorbed was 1.09 calculated from serum concentrations, and 1.05 calculated from urinary excretion of the drug. The apparent volume of distribution was 0.61 l/kg (0.53–0.72 l/kg), 26% higher in males than in females. A two-compartment open model was found to describe the decline in the serum concentrations, giving a mean distribution half-life of 6 min. The intersubject ranges of biological half-life were 8.1–12.1 h and 8.3–12.6 h calculated from serum and urine data, respectively. 24% (18–29%) of the dose was excreted unchanged in urine, which agreed with the relationship between the calculated total body clearance and the renal clearance of the drug.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 343-347 
    ISSN: 1432-1041
    Schlagwort(e): cimetidine ; phenobarbital ; gastro-intestinal absorption ; bioavailability ; renal clearance ; non-renal clearance ; enzyme induction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of orally administered cimetidine was studied in 8 healthy subjects before and after 3 weeks of treatment with phenobarbital 100 mg daily, and in a separate study 4 subjects received cimetidine intravenously before and after the administration of phenobarbital. There was no change in the volume of distribution, but total plasma clearance was increased by a mean of 18%, mainly due to a 37% increase in nonrenal clearance. Renal clearance and half-life were not significantly altered. The area under the plasma concentration-time curve after oral administration was significantly (P≪0.05) reduced by a mean of 15% after phenobarbital treatment. The amount of cimetidine excreted in urine and its sulphoxide metabolite were significantly (P〈0.05) reduced, on average by 34% and 26%, respectively by phenobarbital treatment. The data indicate that an apparent 20% reduction in the absorption of cimetidine was due to induction of gastrointestinal metabolism of cimetidine, with some contribution also from hepatic metabolism. Reduced absorption per se could not be totally excluded. Although the magnitude of the change was small, the finding of an 11% decrease in the time to achieve an effective plasma level of cimetidine after phenobarbital treatment may contribute to the ineffectiveness of cimetidine in certain patients.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 449-452 
    ISSN: 1432-1041
    Schlagwort(e): theophylline ; ethylenediamine ; suppository ; serum concentration ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The absorption of theophylline from a suppository not containing ethylenediamine was tested in 9 healthy volunteers. AUC after rectal administration of anhydrous crystalline theophylline 250 mg (AUCrectal) was compared with the AUC after oral administration of microcrystalline theophylline 250 mg (Nuelin®; AUCoral) in a randomized, cross-over study. The ratio AUCrectal/AUCoral was 0.75 at 10 h, and the ratio AUCrectal×βrectal/AUCoral×βoral extrapolated to infinite time was 0.83. A mean concentration of 5.7 µg/ml was reached 3.7 h after a single rectal dose. The absorption studies were performed with suppositories stored for 15 weeks at 22 °C. No effect on the in vitro release rate of theophylline from the suppository was observed during storage at room temperature from 3 to 31 weeks after production. Since aminophylline suppositories are known to decompose upon storage, the results suggest that a formulation without ethylenediamine is preferable for the rectal administration of theophylline.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 459-463 
    ISSN: 1432-1041
    Schlagwort(e): buflomedil ; vasodilatation ; pharmacokinetics ; bioavailability ; vasoactive drug
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A dose-ranging pharmacokinetic study of buflomedil was carried out in eight subjects to determine the pharmacokinetic parameters of the drug after oral and intravenous administration. Based on AUC∞ analyses, the pharmacokinetics of buflomedil were found to be linear within the dose ranges studied (50 to 200 mg for i. v. injection and 150 to 450 mg for oral administration). In the oral study, the mean biological half-life of the drug was 2.97 h, while after intravenous dose it was 3.25 h. The apparent volume of distribution after the pseudodistribution equilibrium (Fdβ) and volume of distribution at the steady state (Vdss) were 1.43±0.24 l/kg and 1.32±0.26 l/kg, respectively. The mean urinary recovery of intact drug and the metabolite, paradesmethyl buflomedil, after intravenous dosing, were 23.6% and 18.7%, respectively, while after oral dosing, they were 18% and 14.8%, respectively. On the average, 72% of the dose was obserbed into the systemic circulation after oral administration. This level of bioavailability was attributed to the hepatic first-pass effect.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 19 (1981), S. 225-230 
    ISSN: 1432-1041
    Schlagwort(e): fluoride ; sustained release tablets ; serum concentration ; urinary excretion ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Various sodium fluoride tablets used for the treatment of osteoporosis were evaluated. The tablets were characterized in vitro by determining the release curves. The serum levels and urinary recovery of fluoride were determined after a single oral dose either of rapidly soluble (conventional), sustained release or enterocoated tablets. The in vivo study showed that administration of sustained release tablets eliminated high serum peaks and prolonged the duration of an elevated serum level as compared to conventional tablets. The biovailability of the fluoride was lower after intake of sustained release and enterocoated tablets, and there was an increase in the interindividual variance of biovailability.
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 53-58 
    ISSN: 1432-1041
    Schlagwort(e): hydralazine ; food ; absorption ; plasma level ; salivary level ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Single oral doses of hydralazine (Apresoline) 50 mg were administered on two occasions to eight healthy volunteers when fed and fasting. Blood and saliva samples were taken at intervals after dosing and analysed for drug. Heart rate and blood pressure were measured before and at intervals after dosing, at rest, after tilt and exercise. Plasma hydralazine levels showed wide inter-individual variation. The areas under the plasma concentration-time curve (0–8 h), the height of the peak plasma levels and the time to peak were not significantly different between the fed and fasting state. Salivary hydralazine levels were readily measurable but showed little correlation with plasma levels. The heart rate and pulse pressure were increased after drug both at rest, supine and erect, and after exercise for between 6 and 8 h.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 127-133 
    ISSN: 1432-1041
    Schlagwort(e): ketoprofen ; pharmacokinetics ; multipledose ; bioavailability ; assay ; modelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A commercial capsule containing 50 mg of ketoprofen (Orudis), a simple capsule containing 50 mg of ketoprofen alone and 50 mg of ketoprofen in an aqueous solution were given as separate doses in a randomized sequence to 12 normal adult males. The areas under the resulting plasma concentration-time curves (AUC) were remarkably consistent for each volunteer. The bioavailability from the commerical capsule relative to that from the solution was 99.7%±10.5% and that from the simple capsule was 102%±10%. After 6 of the volunteers had taken the commercial capsule 6 hourly for thirteen doses, their AUC extrapolated to infinity was significantly higher (by 22%) than that after the single dose indicating, contrary to previous reports, accumulation upon multiple dosing. The interdose AUC after the thirteenth dose was, however, statistically indistinguishable from the AUC-to-infinity after the single dose as might be expected from linear kinetics. The ketoprofen solution generated peak plasma concentrations in only one-third the time (21±7 min) required for the capsules (commercial, 72±45; simple, 61±39 min). Despite plasma concentrations being tracked over a 200-fold range, log linearity was not established within 12 h in any of the 42 profiles obtained. A two-compartment open model was fitted to the solution data giving excellent prediction of the time-to-peak and clearance (Cl/F=5.2±1.1 l/h) as determined by eye and by log-trapezoidal rule, respectively.
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  • 19
    ISSN: 1432-1041
    Schlagwort(e): zimelidine ; norzimelidine ; antidepressant ; pharmacokinetics ; bioavailability ; urinary excretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Five healthy adults were administered zimelidine orally (150 mg) and by intravenous infusion (20 mg) in a crossover design. Blood and urine samples were collected for a period of 28 hours after dosing and the concentrations of zimelidine and norzimelidine determined. There was no significant difference in terminal phase half-life of zimelidine after oral (4.7 h±1.3 SD) or intravenous dosing (5.1 h±0.7 SD). An average of 50% of the ingested oral dose reached the systemic circulation. Excretion of unchanged zimelidine in urine was on average 1.26% of the intravenous dose. In appears that zimelidine is completely absorbed from the gastrointestinal tract and “first-pass metabolism” in the liver reduces the bioavailability to 50%. The mean plasma half-life for norzimelidine was 22.8 h. The area under the plasma concentration time curve for norzimelidine after oral administration was 92% of that after intravenous administration. The plasma concentration of both zimelidine and norzimelidine are predicted to approach steady-state within 3–5 days.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 20 (1981), S. 225-228 
    ISSN: 1432-1041
    Schlagwort(e): cimetidine ; antacids ; metoclopramide ; absorption ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In 8 healthy subjects the absorption of cimetidine was investigated when given alone, together with 60 ml aluminium/magnesium hyroxyde containing antacid (neutralising capacity 26 mmol HCl/10 ml), and together with liquid metoclopramide 14 mg. The antacid significantly (P〈0.01) reduced the bioavailability (area under the plasma level-time curve) of cimetidine, on average by one third. Metoclopramide also reduced the bioavailability by an average of 22%. The reductions were associated with significantly reduced excretion of cimetidine in urine. There was no change in the half-life or renal clearance of cimetidine, supporting the hypothesis of reduced gastrointestinal absorption. The results indicate that cimetidine and antacids should not be given together, and that the dose of cimetidine may have to be increased if it is administered concomitantly with metoclopramide.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 215 (1981), S. 625-633 
    ISSN: 1432-0878
    Schlagwort(e): Teleost ; Pars intermedia ; Immunocytochemistry ; PAP-technique ; MSH ; ACTH ; Endorphin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pars intermedia of S. mossambicus contains two different endocrine-cell types. The predominant cell type is lead-haematoxyline-positive and assumed to synthesize MSH and related peptides. The second cell type is PAS positive and its function and product(s) are unknown. Staining of light-microscopic and ultrathin sections with antisera against α-MSH, ACTH 1–24 and human β-endorphin revealed that only the lead-haematoxyline-positive cells of the pars intermedia react with these antisera, and that the secretory granules of these cells contain compounds that were immunoreactive to all three antisera. These findings are in line with the hypothesis that α-MSH, ACTH and endorphins are derived from the same precursor molecule. No specific reaction with one of the antisera could be detected in the PAS positive cells.
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  • 22
    ISSN: 1432-0878
    Schlagwort(e): Digestive tract ; Fish ; Gastrin-immunoreactive cells ; Pancreatic polypeptide-immunoreactive cells ; Somatostatin-immunoreactive cells ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Gastrin, pancreatic polypeptide and somatostatin immunoreactive cells in the gut of two fish with stomachs (perch and catfish) and a stomachless fish (carp) were studied by immunocytochemistry. In the gastric mucosa of perch and catfish, cells showing gastrin and somatostatin-like immunoreactivity are found, scattered among the surface mucous cells and mucous neck cells. No pancreatic polypeptide (P.P.) immunoreactive cells are detected in the gastric mucosa. Cells showing gastrin and P.P.-like immunoreactivity are observed in the intestinal mucosa of perch, catfish and carp. In this location no somatostatin immunoreactive cells are found.
    Materialart: Digitale Medien
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  • 23
    ISSN: 1432-0878
    Schlagwort(e): α- and β-Endorphins ; Met-enkephalin ; Brain ; Immunocytochemistry ; Rana temporaria (Amphibia, Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the brain of Rana temporaria, two distinct systems reactive with α- and β-endorphin antisera, respectively, and with a met-enkephalin antiserum, have been detected immunohistochemically. Neurons reacting with α- and β-endorphin antisera are located (1) in the preoptic nucleus, and (2) in the pars ventralis of the tuber cinereum. Immunoreactive nerve fibres of both groups of perikarya end in the infundibular floor near the capillaries and the preoptico-hypophysial tract. Control reactions have shown that the immunoreactivity is suppressed by the corresponding antigens, but also by β-LPH. In view of these results the immunoreactive systems examined correspond to an α/β-endorphin system or a lipotropinergic system. Neurons reacting with the met-enkephalin antiserum are located in the paraventricular organ. Intense immunofluorescence was observed in the infundibular floor. Controls show that the labelling by met-enkephalin antiserum is exclusively suppressed by met-enkephalin. In the pituitary gland, on the other hand, α- and β-endorphin antisera reveal: 1) the MSH/ACTH-like cells of the pars intermedia and 2) the ACTH-like cells of the pars distalis.
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  • 24
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Biologically active peptides ; Lymnaea stagnalis ; Neurohormone ; Neurotransmitter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Perikarya and nerve fibers were immunocytochemically identified in the central nervous system of the pond snail Lymnaea stagnalis by means of the unlabelled antibody enzyme method with antisera to 15 biologically active peptides of vertebrates: vasopressin, vasotocin, oxytocin, α-melanocyte stimulating hormone (α-MSH), met-enkephalin, somatostatin, glucagon, insulin, glucose-dependent insulinotropic peptide (GIP), vaso-active intestinal polypeptide (VIP), gastrin, secretin, pancreatic polypeptide (PP), Substance P, calcitonin. No immunostaining was obtained with antisera to β-endorphin, cholecystokinin (CCK), neurophysin I and II. Particular neurons could be identified with two antisera (anti-vasopressin/vasotocin, anti-α-MSH/metenkephalin, anti-substance P/PP, anti-PP/gastrin). Apparently this indicates that populations of cells identified with a given antiserum may consist of more than one cell type. Only a few of the new peptidergic cells appeared to be identical with classical neurosecretory cells. Thus the growth hormone producing Light Green Cells stained with anti-somatostatin and the axon terminals of the ovulation hormone producing Caudo-Dorsal Cells with anti-met-enkephalin. Whether this indicates structural identity of the growth hormone with somatostatin and of the ovulation hormone with met-enkephalin remains to be investigated. Just like the classical neurosecretory cells a number of the new peptidergic cells (anti-glucagon, -insulin, -met-enkephalin, -somatostatin, and -PP positive cells) send their axons to the peripheries of commissures, connectives or nerves. Thus these cells can be considered as probably neuroendocrine. The classical neurosecretory cells release their products into the haemolymph from these sites. Other new peptidergic cells (e.g., anti-vasopressin, -vasotocin, -oxytocin and -GIP positive cells) have axons that terminate, probably synaptically, on other neurons, indicating that they are “more conventional” neurons, their products being neurotransmitters/neuromodulators. It can also not be excluded that some cells of a population containing a given peptide are neuroendocrine and others make contact with other neurons.
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  • 25
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Vasoactive intestinal polypeptide ; Radioimmunoassay ; Gut hormones ; Anura
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunocytochemical and radioimmunological techniques with region specific antisera have been used to identify a vasoactive intestinal polypeptide-like material in the anuran intestine. Seven species of Anura were investigated: Bombina bombina, Alytes obstetricans, Rana temporaria, Rana esculenta, Hyla arborea, Hyla crepitans and Bufo bufo. In five of the species (A. obstetricans, R. temporaria, H. arborea, H. crepitans and B. bufo) vasoactive intestinal polypeptide-like immunoreactive mucosal endocrine cells and nerve fibres in all layers of the gut wall, were detected by both immunofluorescence and peroxidase-antiperoxidase methods. In the other two species, R. esculenta and B. bombina, no mucosal endocrine cells were detected although the vasoactive intestinal polypeptide-immunoreactive nerve fibres were plentiful. Radioimmunoassay showed the presence of significant amounts of vasoactive intestinal polypeptide-immunoreactivity in intestinal extracts from all species. The highest quantities were present in those anurans with both immunostained cells and nerves. Gel permeation chromatography showed that most of the vasoactive intestinal polypeptide-like peptide eluted in a position identical to that of natural mammalian (porcine) vasoactive intestinal polypeptide. The results indicate that a vasoactive intestinal polypeptide-like peptide is well represented in the Anura and that it is immunologically very similar to the mammalian peptide.
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  • 26
    ISSN: 1432-0878
    Schlagwort(e): Anterior pituitary ; Corticotrophs ; Immunocytochemistry ; Growth hormone ; Prolactin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Two antisera, Y-10 and Y-18 were raised in rabbits against synthetic human β-endorphin conjugated to bovine serum albumin and keyhole limpet haemocyanin respectively. Antiserum Y-10 has been shown by radioimmunoassay to be highly specific for human β-endorphin with minimal or no cross-reactivity against other pituitary peptides whilst antiserum Y-18 crossreacted on an equimolar basis against β-endorphin and β-lipotropin. When used in the immunohistochemical procedure, both antisera specifically stained the corticotrophs in human anterior pituitary tissue. A similar effect was observed when antiserum Y-18 was applied to rat anterior pituitary tissue in the immunohistochemical procedure. Y-10 antiserum, on the other hand, stained not only rat corticotrophs but also somatotrophs. The somatotrophin staining could not be attributed to the enkephalins reported to be present in these cells. The non-specific β-endorphin antiserum Y-18 was used to stain anterior pituitaries from dehydrated and adrenalectomized rats as well as rats of the Brattleboro strain. In tissues from the three experimental animals, cells that stained positively for β-endorphin did not give a positive immunoreaction for ACTH and vice versa in some other sections. It is concluded that under the physiological conditions, formalin fixation of the tissue causes the proopiocortin molecule to be “trapped” in a conformation such that either ACTH or β-endorphin-like determinants are available for reacting with the appropriate antiserum.
    Materialart: Digitale Medien
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  • 27
    ISSN: 1432-0878
    Schlagwort(e): Neuropeptides ; Substance P ; Chicken gut ; Radioimmunoassay ; Immunocytochemistry ; Smooth muscle motility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution and cellular localization of substance P in the chicken gut was studied by immunocytochemistry and immunochemistry. Substance P-containing nerve fibers are numerous in the gut wall. They occur in the smooth muscle layer as well as in the mucosa, where they are associated with blood vessels or surround the intestinal crypts. The fibers are particularly numerous in the myenteric and submucosal plexuses, where substance P-containing nerve-cell perikarya are also encountered. Substance P was found also in scattered endocrine cells of the small intestine, caeca and colon. Previously, bombesin-containing cells, which are numerous in the proventriculus, have been mistakenly identified as substance P cells due to crossreactivity of certain antisera against substance P. Immunochemistry revealed the highest concentration of substance P in the duodenum. The gel chromatographic behavior of chicken substance P differs slightly from that of synthetic bovine substance P, suggesting that chicken substance P differs structurally from mammalian substance P. Substance P-containing nerve fibers in the chicken gut develop slowly after hatching, apparently beginning in the duodenum; at approximately 20 weeks after hatching the distribution pattern is fully developed. A functional investigation was performed on the isolated chicken caecum to clarify the role of substance P in the contractile behavior of smooth muscle. Substance P contracted the caecum over a wide dose range; the contractile response was greater in 20 week-old chickens than in 4 and 10 week-old animals. Electrical field stimulation caused a relaxation of the caecum and a contraction upon cessation of stimulation. Neither of these responses, both of which are neurally mediated, were inhibited by adrenergic and cholinergic blockade. It is conceivable that the contractile response following electrical stimulation is caused by substance P released from nerve fibers in the smooth muscle.
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  • 28
    ISSN: 1432-0878
    Schlagwort(e): Pituitary ; Immunocytochemistry ; Prolactin ; Somatotropin ; Lepidosiren
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The cellular binding sites of anti-oPRL IgG and anti-bSTH IgG were demonstrated in the pituitary glands of Lepidosiren paradoxa, Rana temporaria and Ambystoma mexicanum by means of the unlabeled antibody enzyme method by light and electron microscopy (the latter only in Lepidosiren). With the light microscope PRL or PRL-like substances and STH or STH-like substances were revealed in two different cell types in the distal lobe corresponding to the acidophils. However, as a result of the insufficient differentiation of the acidophils in Lepidosiren after staining with Brookes' procedure it was not possible to distinguish the two types of acidophils in this animal. Treatment with low dilutions of both anti-oPRL and anti-bSTH IgG revealed simultaneous immunocytochemical staining in both types of acidophils in Lepidosiren and in Rana. These results, indicating that there is antigenic cross-reaction between anti-oPRL and anti-bSTH IgG and both PRL and STH in these animals, are discussed. The electron microscopic investigations of Lepidosiren revealed that the specific anti-oPRL IgG reactive cells contain granules ranging in size from 200 to 300 nm, while the specific anti-bSTH IgG reactive cells contain smaller immunoreactive granules ranging from 80 to 160nm.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 19-22 
    ISSN: 1612-1112
    Schlagwort(e): Teflon columns ; Chemically modified teflon ; Gas chromatography ; Capillary columns
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Wall-coated open tubular columns prepared from chemically modified teflon tubing have been developed for gas chromatography. Chemical reaction of the inner walls of teflon tubing allows bonding of an adhesive layer on which a variety of stationary phaes can be coated. Test mixtures of alkanes and alcohols were used to investigate the chromatographic properties of these columns and the stability and mixing of the adhesive and stationary phae layers. the results in dicate that mixing of the layers is negligible and that the column is stable for a long period of time.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 55-66 
    ISSN: 1612-1112
    Schlagwort(e): Capillary columns, glass ; Gas chromatography ; Column preparation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Kapillar-Gas-Chromatographie ist heute das sich am stärksten entwickelnde Gebiet der Gas-Chromatographie. Es gibt viele komplexe, neue Fragestellungen in der Analytik, welche den Einsatz spezieller Kapillarsäulen erfordem. Glücklicherweise gibt es aber auch eine große Zahl von Herstellungsverfahren für Kapillarsäulen, welche — noch mehr als bei der Herstellung von gepackten Säulen — eine Anpassung an die gestellten Aufgaben ermöglichen. In diesem Artikel werden die Herstellungsverfahren für Kapillarsäulen zusammengestellt und Anregungen gegeben, wie aufgaben-orientierte Säulen erreicht werden.
    Notizen: Summary Glass capillary column chromatography is the most rapidly growing part of gas chromatography. There are many complex new analytical tasks and they require special capillary columns, Fortunately there is a wide range of column preparation methods available, and they make the preparation of glass capillary columns a more varied job than that of packed columns. In this paper these methods are reviewed and suggestions are given for making task-oriented columns.
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  • 31
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Urea herbicides ; Catalytic hydrolysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method is described for the rapid catalytic hydrolysis of phenylurea herbicides on silica gel at elevated temperatures. After derivatisation of the anilines produced with heptafluorobutyric acid anhydride final analysis is done on a gas chromatograph equipped with an electroncapture detector. Detection limits are in the 1–5 picogram range. The method has successfully been applied to residue analysis of water samples at the 1 ppb level. The determination of free anilines present in water samples and the potential of various techniques to be used to discriminate between free anilines and parent herbicides are also discussed.
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  • 32
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Graphitised carbon black ; Phenols ; Water pllutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The fractionation of eleven phenols which may be contaminants in drinking water has been accomplished by using acid-washed graphitised carbon black modified with trimesic acid and PEG 20 M.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 447-451 
    ISSN: 1612-1112
    Schlagwort(e): Headspace analysis ; Gas chromatography ; Residual analysis of polyethylene terephthalate ; Acetylene reduction assay ; Ethylene evolution in germinating seed ; Acetaldehyde generation in polyester resin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary New application areas for headspace gas chromatography in agricultural and polymer degradation research are described. Specific examples are drawn from the various forms of headspace analysis with emphasis on the automated static equilibrium method.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 105 (1981), S. 333-339 
    ISSN: 1615-6102
    Schlagwort(e): Immunocytochemistry ; Pea seed ; Protein histochemistry ; Storage proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The pea seed storage proteins legumin and vicilin have been localized by electron microscopy using a post-embedding immunocytochemical double-labelling technique. Highly purified antibodies from sheep, specific to legumin and vicilin, were sequentially reacted on sections of pea cotyledon tissue embedded in glycol methacrylate or Spurr's epoxy resin. The sheep antibodies were visualized indirectly by reaction with Staphylococcal Protein A labelled with colloidal gold. Two discrete sizes of colloidal gold particles can be used for simultaneous localization of two antigens. In near mature tissue, the storage proteins are restricted to organelles, called protein bodies. Individual protein bodies contain both legumin and vicilin.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 9 (1981), S. 41-58 
    ISSN: 1573-8744
    Schlagwort(e): transepidermal ; pharmacokinetics ; bioavailability ; drug surveillance ; compliance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Continuous transepidermal drug collection (CTDC) has been proposed for use in assessing ethanol intake and in monitoring compliance with therapeutic regimens. Exploration of a theoretical basis for use of CTDC in these circumstances and for its use in assessing other aspects of drug disposition kinetics was undertaken. Effects of single and multicompartmental drug disposition models, single dose and multiple dose regimens, with regular and irregular doses and dosing intervals, and zero-order, first-order, and Michaelis-Menten excretion patterns were explored. First-order transepidermal drug transfer was assumed with and without back transfer from the collection device. These analyses suggest that the utility of CTDC is severely restricted when back transfer from the collection device is substantial. With back transfer minimized, CTDC may be a useful tool for assessing amount of drug exposure, compliance with therapeutic regimens, and relative bioavailability, but offers little advantage over discrete sampling of other body fluids in the study of other aspects of drug disposition kinetics.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 9 (1981), S. 389-417 
    ISSN: 1573-8744
    Schlagwort(e): Prednisone ; prednisolone ; dose-dependent ; pharmacokinetics ; biotransformation ; protein binding ; bioavailability ; transcortin binding ; interconversion ; renal clearance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Six healthy male volunteers were given 5, 20, and 50 mg of oral prednisone and 5, 20, and 40 mg doses of intravenous prednisolone. Plasma and urine concentrations of prednisone and prednisolone were determined by HPLC, and the binding of prednisolone to plasma proteins was measured by radioisotopic and equilibrium dialysis techniques. The pharmacokinetics of both oral prednisone and intravenous prednisolone were dose-dependent. The mean oral dose plasma clearances of prednisone ranged from 572 ml/min/ 1.73 m 2 for the 5mg dose to 2271 ml/min/1.73 m 2 for the 50 mg dose. Changes in prednisone half-life were insignificant, but increases in the half-life of its metabolite were dose-dependent. The systemic plasma clearance of i.v. prednisolone was dose-dependent and increased from 111 to 194 ml/min/1.73 m 2 over the 5 to 40 mg i.v. dosage range. The steady-state volume of distribution also increased, but little change in mean transit time and half-life was found. The binding of prednisolone to plasma proteins was markedly concentration-dependent, and a two compartment, nonlinear equation was used to characterize the effective binding of prednisolone to transcortin and albumin. The apparent pharmacokinetic parameters of protein-free and transcortin-free prednisolone were relatively constant with dose. The interconversion of prednisone and prednisolone varied with time and dose, although prednisolone concentrations dominated by 4-to 10-fold over prednisone. In urine, 2–5% of either administered drug was excreted as prednisone and 11–24% as prednisolone. The apparent renal clearances of both steroids were also nonlinear and unrelated to protein binding. These studies indicate that the pharmacokinetics of prednisone and prednisolone are dose-dependent and that protein binding does not fully explain their apparent nonlinear distribution and disposition.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 9 (1981), S. 535-551 
    ISSN: 1573-8744
    Schlagwort(e): sisomicin ; pharmacokinetics ; bioavailability ; two-compartment open model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Detailed analyses of the pharmacokinetics of sisomicin administered at doses of 25, 50, and 100 mg intravenously and intramuscularly to healthy volunteers established that the drug is handled by a two-compartment open model system with a disposition (elimination) half-life of 2.6 hr. The kinetic estimates over this dose range are linear and independent of dose and were verified by a 60-min infusion experiment in which dose and the maximum serum concentration achieved (5 μg/ml) were predicted correctly. Sisomicin was rapidly distributed to the tissue compartment, and equilibrium between the central and the tissue compartment was established by 30 min after dosing. Renal clearance (55 ml/min) of sisomicin was about 30% less than total body clearance (78 ml/min). Total urinary excretion of sisomicin during a 24-hr period following drug administration was about 70% of the dose. The disposition kinetics of sisomicin following intramuscular administration are similar to those obtained following rapid intravenous administration. Intramuscular bioavailability of sisomicin for the doses of 25, 50, and 100 mg was greater than 95%. Based on these results, various initial loading infusion doses and maintenance infusion rates were calculated to provide specific desired peak and steady-state serum sisomicin concentrations rapidly. The purpose was not to expose patients to potentially toxic high peak concentrations of drug while maintaining these concentrations during the current therapeutic dosing intervals of 8 to 12 hr.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 9 (1981), S. 679-691 
    ISSN: 1573-8744
    Schlagwort(e): diazepam ; controlled release ; bioavailability ; single dose ; steady-state
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A controlled release formulation of diazepam was compared to equal daily doses of the trade tablet under single day and steadystate conditions. Virtually no differences were found in the mean steadystate concentrations of diazepam or its metabolite, N-desmethyldiazepam, when the subjects received the 5 mg trade tablet three times daily or the 15 mg controlled release formulation once daily. Similarly, there was no difference in mean diazepam or N-desmethyldiazepam plasma concentrations when single doses of the controlled release formulation were given to fed or fasted volunteers. These data indicate that the controlled release formulation produces plasma concentrations of diazepam and N-desmethyldiazepam comparable to those achieved with the same daily dose of the trade product given three times daily, suggesting that these regimens can be used interchangeably.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 9 (1981), S. 725-738 
    ISSN: 1573-8744
    Schlagwort(e): pharmacokinetics ; chlorpheniramine ; first-pass effect ; bioavailability ; gut metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The oral absolute bioavailabilities of chloropheniramine (CPM) in four rabbits (New Zealand White, male, mean wt. 3.71 kg), averaged 0.06±0.03, 0.11±0.08, and 0.09±0.01 following a 3, 10.5, and 21 mg/kg dose, respectively. The individual bioavailability data and the AUCof one of the demethylated metabolites, desdimethyl CPM (DDCPM) obtained following different doses suggested the existence of saturable presystemic elimination. Two rabbits received an additional 10.5 mg/kg dose of CPM through portal vein infusion. Based on the oral, intraportal vein and i.v. studies, the mean extraction ratios of gut and the liver calculated for these two rabbits averaged 0.58 and 0.76, respectively. The latter value agreed well with the estimated hepatic extraction ratio from the in vitro liver homogenate study (0.89) or from the i.v. studies (0.83). The extensive prehepatic first-pass effect observed in the present study was consistent with similar findings in humans and dogs.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 9 (1981), S. 1-14 
    ISSN: 1573-8744
    Schlagwort(e): prednisone ; prednisolone ; dexamethasone ; pharmacokinetics ; tobacco ; smoking ; bioavailability ; corticosteroids ; enzyme induction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The pharmacokinetics of oral prednisone and oral dexamethasone were examined in 18 healthy male adults. Eight subjects also received intravenous prednisolone and intravenous dexamethasone. Half of each group were cigarette smokers as confirmed by plasma thiocyanate concentrations. Plasma and urine concentrations of prednisone and prednisolone were assayed by high performance liquid chromatography, while plasma dexamethasone was measured by radioimmunoassay. There were no statistically significant differences between smokers and nonsmokers in the systemic availability of prednisolone (75 versus 84%), oral dose clearance of prednisone (29 versus 27 ml/min/kg), systemic prednisolone clearance (2.8 versus 2.9 ml/min/kg), or in the interconversion rates, volumes of distribution, or urinary recoveries of prednisone and prednisolone. Similarly, the pharmacokinetics of dexamethasone were unaffected by smoking. A limited correlation (r=0.55) was found between the high oral dose clearances of prednisone and the lower values of dexamethasone (6.73 and 5.71 ml/min/kg in smokers and nonsmokers). A two- to threefold variability occurred in oral dose clearances of each steroid with partial intrasubject covariance. Unlike the anticonvulsants, which markedly induce corticosteroid metabolism, smoking has no effect on their pharmacokinetics and should not complicate therapy with these drugs.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 220 (1981), S. 115-123 
    ISSN: 1432-0878
    Schlagwort(e): Pars distalis ; California leaf-nosed bat ; Macrotus californicus ; LH ; FSH ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) cells were immunostained in the anterior pituitary lobe of the California leaf-nosed bat with antisera against the specific beta (β) subunits of rat LH and rat FSH employing the unlabeled immunoperoxidase technique. Selective immunochemical staining by both antisera was localized primarily in the same cell type. However, some cells consistently reacted solely with antisera to either LH-β or FSH-β. Whereas the immunoreactive LH-β cells, in general, stained more intensely than FSH-β cells they were usually less numerous. These cells were alcian-blue and PAS-positive, staining pink to purple. The LH/FSH cells were pleomorphic with eccentric nuclei, often with cytoplasmic extensions. They were found throughout the pars distalis.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 220 (1981), S. 279-292 
    ISSN: 1432-0878
    Schlagwort(e): Endocrine cells ; Gastrointestinal tract ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of gastrin-, cholecystokinin-, glucagon-, secretin-, vasoactive intestinal polypeptide-, substance P-, bombesin-, neurotensin-, motilin-, somatostatin- and avian pancreatic polypeptide-like cells, demonstrated by indirect immunocytochemistry, was studied in samples from the following regions: proventriculus, gizzard, pylorus, duodenum, upper and lower ileum, caeca and rectum. The pylorus is particularly rich in gastrin-, neurotensin- and somatostatin-like cells. No cells immunoreactive for gastric inhibitory polypeptide or insulin were detected. In a number of instances the same cells were found to stain with antisera raised to different gut peptides. This happened with antisera detecting gastrin- and neurotensin-like cells, with antisera to avian pancreatic polypeptide and glucagon and with antisera to secretin, vasoactive intestinal polypeptide, glucagon and substance P. The possibility that antigenic determinants to more than one peptide are contained in certain endocrine-like cells is considered.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 576-578 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Tortuosity factor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The relationship between the obstructive factor γ and velocity was restudied. The dependence of the obstructive factor on velocity was verified. The effects of diffusion coefficient and particle-to-column diameter ratio on the obstructive factor-velocity relationship were investigated. The results are consistent with Hawkes' hypothesis that values of γ at low velocities are averages over tightly packed and loosely packed domains while at high velocities they are weighted in favour of the loosely packed domains where there is more flow.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 648-652 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Gas-liquid adsorption ; Bulk solution ; Mixed stationary phases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary It is shown that the blending of some retention effects can make the resolution of complex mixtures on short classical columns as effective as on capillary columns.
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 699-703 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Headspace analysis ; Aromatic hydrocarbons ; Water analyses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The possibilities of using headspace analysis of aromatic hydrocarbon traces in aqueous solutions with changing values of the partition coefficients are discussed. A variant of headspace analysis of the simplest aromatic hydrocarbon in natural and waste water is described. It involves two-step gaseous extraction of a sample in vessels of varying volume before and after the equilibrium phase is replaced with a pure gas (air or nitrogen). This method permits to analyse 5–50 ml water samples with benzene and toluene contents varying from the ppb to the ppm range within an error not exceeding 155. The analysis time is about 1.5 h. The presence of non-volatile organic or mineral substances does not influence the determination. This method is unsuitable to heterogeneous systems (aqueous oil emulsions): before carrying out the analysis for the hydrocarbon content these systems have to be homogenized first.
    Materialart: Digitale Medien
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  • 46
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Open tubular (capillary) columns ; Glass columns ; Fused-silica columns ; Column testing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Column characteristics affecting the chromatographic behavior of glass and siliceous glass (“fused silica”) capillary columns include the dimensional uniformity of the column, the physical and chemical characteristics of the column wall and the characteristics of the liquid phase. In the case of the coated column the uniformity and thickness of the liquid phase film are the most important criteria affecting column reproducibility. The paper discusses these factors and their influence on column performance.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 203-211 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Quantitative analysis ; Copper oxide converter ; Inorganic gas analysis ; Determination of fluorine and oxygen ; Hydrocarbon analysis ; Wine analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A review of past activities concerning selected industrial analytical problems is given. This includes the following question: preparation of pure gas mixtures to be used for calibration, catalytic conversion of ester and pyridin samples to carbon dioxide and a one-point calibration method using peak heights, both for quantitative analysis, analysis of gas mixtures containing fluorine and inorganic fluorine compounds and the determination of the oxygen and fluorine content of the sample, separation and identification of hydrocarbons in shale oil and petroleum fraction samples, and analysis of wine.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 143-147 
    ISSN: 1612-1112
    Schlagwort(e): Capillary columns ; Gas chromatography ; Retention index ; Structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The retention index of twenty different homologous series of esters have been determined experimentally on polar (Carbowax 1540) and non-polar (squalane) columns. General equations to calculate retention index have been established by statistical methods. The influence of the length and inductive effect of acid and alcohol chains and the relative position of the carboxylic group are discussed.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 285-288 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Porous layer open tubular columns ; Kaolin as support ; Column performance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary PLOT columns have been prepared with kaolin as the liquid phase support. These columns show good efficiency with different stationary phases and good thermal stability with polar phases. The performance of columns is shown by the separation of various mixtures such as fatty acids, phenols and anilines which are of analytical importance.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 39-40 
    ISSN: 1612-1112
    Schlagwort(e): Xylidine isomers ; Heteroaromatic liquid phases ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Nicotinic acid and 1H-benzotriazole appreciably resolved all the xylidine (dimethylaniline) isomers, while benzimidazole, nicotinamide and phthalimide can also separate all the isomers except 2,4- and 2,3-xylidines. The analyses were carried out on supports which were not treated with an alkali.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 345-350 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Silica capillaries ; Glass capillaries ; Mixed gum phases ; Polarity and selectivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Mixed phases of Superox 20M and OV-1 can be coated homogeneously on the untreated wall of fused silica capillary columns. Excellent columns with regard to efficiency, inertness and thermal stability can be obtained. (CE〉95% and MAOT≥250°). The polarity and selectivity were ascertained with Rohrschneider-Reynolds probes and a capillary polarity test mixture. The analysis of an essential oil mixture illustrates the possibilities of mixed phases in practical capillary GC.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 387-397 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Capillary columns ; Fused silica ; Contact angle ; Wettability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary This paper describes the systematic characterization of glass and the newly introduced fused silica and quartz capillary columns from surface wettability measurements. Common gas chromatographic stationary phases were used in capillary-rise measurements at temperatures up to 300°C. By construction of Zisman plots and using the Cassie equation, the relative surface concentrations of wettable and non-wettable groups were determined. By application of the Fowkes equation, the dispersion force component of the surface energy was investigated. The influence of various surface treatments such as leaching, silylation, and polymeric film formation are discussed. Wettability measurements were also used to evaluate the thermostability of various treated surfaces and to compare the surface properties of glass, quartz, and fused silica. The wettability of the surfaces with selected stationary phases as a function of temperature is also discussed.
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  • 53
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Polycyclic aromatic hydrocarbons ; Retention index ; Average molecular polarizabilities
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A significant correlation has been found between the retention indices of polycyclic aromatic hydrocarbons on non-polar stationary phases and the average molecular polarizabilities of the molecules separated on these phases. Equations have been derived for the determination of the average molecular polarizabilities, directly from the retention indices.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 69-72 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Polynuclear aromatic hydrocarbons ; Retention index ; Vapour pressure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The retention index of a planar polynuclear aromatic hydrocarbon on the GC phases OV-101, SE-52, and OV-17 is strictly related only to the boiling point, and less closely to the relative molecular mass. The very approximates relation with connectivity index ins only a consequence of the latter. On a nematic lqiuid crystal phase, a variation of activity coefficient, expressed in terms of a shape factor, also influences the retention of PAH.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 269-276 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Detector performance ; Trace analysis ; Catalytic conversion ; Multidimensional gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Relationships are derived describing how the detection limit of a chromatographic system depends on the minimum detectable limit of the detector and the chromatographic parameters such as column length, efficiency, carrier gas flow rate and the capacity factor. Performance data of detectors developed in the last 25 years at the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences are given and a few selected application examples are listed. These include trace analysis by preconcentration and by direct analysis and the utilization of multidimensional gas chromatography with two columns, two detectors, a 12-port valve, and a catalytic conversion reactor.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 277-278 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; C1−C5 Hydrocarbons ; Dimethyl ether
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary An analytical GC method was developed which uses a single packed column consisting of three packings in series prepared with the following liquid phases: dimethyl sulfolane, propylene carbonate, and silver nitrate. This system provides satisfactory resolution of mixtures of C1−C5 hydrocarbons and dimethyl ether obtained when converting methanol to gasoline. Due to the high capacity of the column it is possible to inject larger sample amounts permitting trace analysis.
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  • 57
    ISSN: 1612-1112
    Schlagwort(e): Phthalides ; Umbelliferae ; Liquid-solid chromatography ; Gas chromatography ; Ligustilide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A liquid-solid chromatographic pre-fractionation of naturally occurring phthalides has been developed. The LSC was carried out on a column of silica applying a 1–50% gradient elution of diethyl ether (containing 2% methanol) in pentane. The enrichment in the fractions led to better possibilities for a gas chromatographic separation and isolation allowing further studies by spectroscopic methods. Ligustilide may easily isomerize during GC as a result of ageing of the column.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 601-602 
    ISSN: 1612-1112
    Schlagwort(e): Ethanolamines ; Ethylene glycols ; Direct separation ; Gas chromatography ; Short glass capillaries
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary An effective and rapid GC separation of ethanolamines, even in the presence of ethylene glycols, using short glass capillary columns is developed. No preliminary derivatisation of the sample is necessary. The separation is completed in 6 minutes.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 507-509 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Headspace ; Phenol ; Urine ; Enzymatic hydrolysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new method has been developed for the determination of phenol in urine in which the phenol conjugates are hydrolysed enzymatically and the liberated phenol is analysed by headspace chromatography. The results compare favourably with those obtained by the method of van Haaften and Sie in which acid hydrolysis is carried out in a heated GC precolumn. The enzymatic hydrolysis headspace technique appears to be very reliable and does not suffer from the disadvantages of precolumn acid hydrolysis.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 421-424 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Liquid sulfur ; McReynolds' constants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The McReynolds' constants for liquid sulfur as a stationary phase in gas-liquid chromatography (GLC) are presented. A simple graphical method of pattern analysis is used to indicate the uniqueness of the sulfur column as compared with other stationary liquid phases characterized by McReynolds. The limitations of using a single factor (as polarity) for the basis for the selection of GLC columns is discussed.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 14 (1981), S. 351-354 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Kováts retention indices ; Propellants ; Solvents ; Aerosol packs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Summary A gas chromatographic method is described by which a nearly complete separation of all commonly used propellants and solvents and their identification and determination can be achieved in one step. The separation is by simple adsorption chromatography on columns packed with Porapak-T with a temperature program 100–180°C at 10°C/min. Kováts' retention indices have been calculated for isothermal conditions at 150°C respectively 100°C for the propellants, at 180°C for the solvents. An exact identification of the propellants and solvents by means of the Kováts' indices is practicable even in complex mixtures.
    Notizen: Zusammenfassung Es wird eine gas-chromatographische Methode angegeben, welche eine fast vollständige Auftrennung aller handelsüblichen Aerosol-Treibgase und Lösungsmittel und ihre Identifizierung und Bestimmung in einem Schritt gestatet. Die Trennung erfolgt durch reine Adsorptions-Chromatographie and Porapak T-Säulen bei 100–180°C mit einer Temperaturate von 10°C/min. Zur Bestimmung der Retentionsindices nach Kovats wurden die Treibgase isotherm bei 150°C bzw. 100°C, die Lösungsmittel bei 180°C aufgetrennt. Anhand der Kovats-Indices ist eine eindeutige Identifizierung der Treibgase und Lösungsmittel selbst in vielfältigen Gemischen möglich.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 215 (1981), S. 41-45 
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamic lesions ; Somatostatin fibers ; Median eminence ; Neural lobe ; Immunocytochemistry ; Frog
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A light microscopic immunocytochemical study of the brain of frogs with hypothalamic lesions was performed in order to obtain evidence concerning the origin of somatostatin fibers in the median eminence and neural lobe of the hypophysis. The results indicate that the somatostatin fibers of the neural lobe originate from somatostatin perikarya located in the prechiasmatic part of the hypothalamus and possibly also in the telencephalon. The somatostatin neurons of the pars ventralis tuberis cinerei do not send axons to the neural lobe. The frog median eminence contains axon terminals of somatostatin neurons located in the pars ventralis of the tuber cinereum. Many other somatostatin fibers of the frog median eminence originate from somatostatin neurons located outside the tuber cinereum. Most of these neurons probably lie in the preoptic hypothalamic region.
    Materialart: Digitale Medien
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 215 (1981), S. 75-86 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary cells ; Estrogen ; Progesterone ; Autoradiography ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of progesterone pretreatment on in vivo 3H-estrogen uptake by five anterior pituitary cell types was analyzed by means of a quantitative autoradiographic-immunocytochemical technique. Male and female rats castrated for 14 days show nuclear concentration of label in all five cell types one h after injection of 3H-estradiol, whether progesterone treated or not. The order of labeling intensity is gonadotropes ≧ lactotropes = somatotropes 〉 thyrotropes = corticotropes. Progesterone treatment induces a dramatic sexual dimorphism in estrogen uptake; it significantly increases 3H-estrogen uptake in all female cell types. In males, progesterone decreases uptake in gonadotropes while not altering uptake in other cell types.
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 215 (1981), S. 333-340 
    ISSN: 1432-0878
    Schlagwort(e): ACTH-opiocortin system ; Immunocytochemistry ; Median eminence ; Neural lobe
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary By immunocytochemical methods, the present study describes ACTH-immunoreactive fibers in the pituitary stalk and neural lobe. This opiocortin-hypothalamo-neural lobe projection arises in a bed nucleus of perikarya in the basal hypothalamus, follows supraoptico-hypophyseal fibers in the zona interna of the median eminence, and distributes throughout the neural lobe. No ACTH-immunoreactive fibers project to the zona externa; some are present in the subependymal layer and at the lateral margins of the median eminence. Further studies must identify the role of these fibers in posterior lobe function. It remains also to be determined whether this system terminates upon primary pituitary portal capillaries and delivers opiocortin neuropeptides to the adenohypophysis.
    Materialart: Digitale Medien
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  • 65
    ISSN: 1432-0878
    Schlagwort(e): 17–39 ACTH ; LHRH terminals ; Median eminence ; Guinea pig ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary At the ultrastructural level a peptide immunocytochemically related to ACTH was localized in LHRH-containing terminals and nerve fibers of the palisade zone in the median eminence of the guinea pig. Precise comparisons of adjacent ultrathin sections stained for 17–39 ACTH and for LHRH made it possible to state clearly that in the two cases the staining was confined to granules containing both peptides. The significance of such an association remains open to discussion.
    Materialart: Digitale Medien
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  • 66
    ISSN: 1432-0878
    Schlagwort(e): Neurotensin ; Hypothalamus ; Coturnix quail ; Immunocytochemistry ; Neuropeptide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The hypothalamus of Japanese quail, Coturnix coturnix japonica, has been studied by means of the peroxidase-antiperoxidase immunocytochemical method, with the use of antibodies to synthetic neurotensin (NT). A number of immunoreactive neuronal perikarya occur in the medial preoptic nucleus of the rostral hypothalamus and a few in the accessory part of paraventricular nucleus and dorsal portion of the infundibular nucleus. Some of them correspond to the parvocellular neurons previously identified tentatively as neurosecretory (Mikami et al. 1975, 1976). Large numbers of immunoreactive neuronal fibers are found in the preoptic area, which extend as a remarkable fiber tract from this area to the ventral septal area and to the subfornical organ. A few immunoreactive fibers also extend ventrocaudally to the infundibular nucleus and to the neural lobe.
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  • 67
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamic deafferentation ; Immunocytochemistry ; Vasopressin ; ACTH/opiocortin ; LHRH
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Luteinizing hormone-releasing hormone (LHRH), vasopressin, and corticotropin systems were examined by immunocytochemical methods in male rats 2 to 20 days after deafferentation of the basal hypothalamus. Axonal degeneration of the vasopressin system (whose perikarya lie rostral to the island) and the corticotropin system (whose perikarya lie within the island) was examined and compared with the response of the LHRH system. Vasopressin immunoreactive staining was absent in the internal zone of the median eminence 10 and 20 days after deafferentation. Disruption of the efferent projections of the opiocortin system caused the loss of almost all fiber staining outside the island by the 5th postoperative day. LHRH staining in the median eminence was modestly reduced in 5 days, considerably reduced in 10 days and negligible 20 days after deafferentation. At 10 and/or 20 days after deafferentation densely stained fibers of all three systems were observed on both sides of the cut. Invasive vasopressinergic fibers reached the lateral median eminence by the 20th postoperative day. This study reports on the response of three neuropeptide systems after complete deafferentation and demonstrates that regeneration can occur across the knife cut.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 215 (1981), S. 499-504 
    ISSN: 1432-0878
    Schlagwort(e): Androgen receptors ; Pituitary gland ; Rhesus monkey ; Autoradiography ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The uptake and retention of radiolabelled dihydrotestosterone by the pituitary gland was examined in the rhesus monkey. Two animals were given an intravenous injection of 1.0μg/kg 3H-dihydrotestosterone (DHT) alone while one monkey received both the labelled androgen and 100μg/kg of unlabelled steroid. One and a half hours later, they were sacrificed. The pituitary glands were removed and processed for autoradiography and immunocytochemistry. Autoradiographic localization of DHT was discernible in the partes nervosa, intermedia and distalis, albeit the highest concentration of radiolabelled cells was noted in the pars distalis. Immunocytochemical staining with antibodies to rat PRL, human TSHβ and ovine LHβ revealed a population of steroid-concentrating cells that contained TSH and a second group that contained LH. None of the cells that reacted with the anti-PRL serum were radiolabelled.
    Materialart: Digitale Medien
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  • 69
    ISSN: 1432-0878
    Schlagwort(e): Proctolin ; Periplaneta americana ; Terminal ganglion-hindgut system ; Immunocytochemistry ; Cobalt iontophoresis technique
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the American cockroach, the distribution and connections of neuronal elements of the terminal ganglion-proctodeal nerve-hindgut system were investigated by means of immunohistochemical methods and axonal CoCl2 iontophoresis. Proctolinlike immunoreactivity was localized within neurons of the terminal ganglion projecting into the proctodeal nerve on the one hand, and in nerve cells without a direct connection to this system on the other. Immunohistochemically, in whole mount preparations fibres of the proctodeal nerve and terminal structures in the hindgut musculature exhibit strong proctolinlike immunoreactivity. At the light- and electron-microscopic levels the pathways of about 30 somata of the proctodeal neural system were characterized by cobalt chloride iontophoresis. The relationships of cobalt filled and immunoreactive neuronal structures are discussed. For the preparation of tritiated proctolin we thank Dr. S. Reißmann, WB Biochemie, Sektion Biologie, FSU Jena
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  • 70
    ISSN: 1432-0878
    Schlagwort(e): Neurohypophysis ; Neurophysins ; Intra-axonal transport ; Immunocytochemistry ; Colchicine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Small doses (3.5 μg and 7 μg) of colchicine injected intracisternally caused an interruption of transport of secretory material from the supraoptic and paraventricular nuclei of the hypothalamus to the neural lobe of the pituitary gland. Transport was assessed by direct measurement of the incorporation of [35S] cysteine into neurophysins, by radioimmunoassay of accumulated material in discrete areas of the system and by immunocytochemistry. The larger dose (7 μg) switched off transport completely during the first 24 h but the system began to recover within three to four days. Colchicine had little, if any, effect on synthesis; comparison of the relationships of the apparent amounts of immunoreactive neurophysins and immunoreactive hormones in the arrested product led to the conclusion that processing of the hormone precursors continues within the secretory granules which accumulated in the perikarya.
    Materialart: Digitale Medien
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  • 71
    ISSN: 1432-0878
    Schlagwort(e): Magnocellular neurosecretory system ; Cholecystokinin ; Oxytocin-neurophysin neurons ; Immunocytochemistry ; Neuropeptides
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The existence of cholecystokinin in the posterior hypophysis and its hypothalamic origin have been unequivocally demonstrated. Immunocytochemical evidence is presented for the coexistence of gastrin-cholecystokinin and oxytocin-neurophysin I immunoreactivities in some magnocellular neurons of the supraoptic and paraventricular nuclei both in rat and bovine hypothalamus.
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 221 (1981), S. 257-267 
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Human pituitary hormone antisera ; Platyfish ; Pituitary gland
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In this communication we describe the immunocytochemical cross-reactivity between antisera to various human pituitary hormones and specific hormone producing cell types in the pituitary gland of sexually mature male platyfish (Xiphophorus maculatus). Antisera to human pituitary hormones cross-reacted either with cells known to produce corresponding hormones (or hormone subunits) in the platyfish (e.g., ACTH, prolactin, TSH β, LH α, FSH α, TSH α) or with no pituitary cells at all (e.g., LH β, FSH β). The one exception was antiserum to human growth hormone which cross-reacted with MSH and ACTH producing cells. The platyfish pituitary is proposed as a test system for immunocytochemically screening antisera for purity and specificity in order to determine their applicability in particular studies.
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 218 (1981), S. 659-662 
    ISSN: 1432-0878
    Schlagwort(e): Peptides ; Subcommissural organ ; Secretion ; Immunocytochemistry ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The results of a preliminary immunocytochemical investigation on the subcommissural organ (SCO) in rats show that (1) Reissner's fiber (RF) or essential compounds of the RF are produced by the SCO, (2) the immunoreactive material is produced in the epithelial cells of the SCO as well as in the hypendymal cells, and (3) the immunoreactive material of the SCO belongs to a category of endogenous peptides to date not demonstrable immunocytochemically in other brain structures.
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 219 (1981), S. 213-216 
    ISSN: 1432-0878
    Schlagwort(e): Relaxin ; Human pregnancy ; Corpus luteum ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Corpora lutea from 12 pregnant women were prepared for immunohistochemical localization of relaxin using a highly specific antiserum. A positive response is given by luteal cells that are diffusely distributed throughout the corpus luteum. These cells do not form a distinctive group in any particular area. A negative response is seen in the adjacent ovarian tissue, and also in nongestational corpora lutea in an early luteal phase.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    ISSN: 1432-0878
    Schlagwort(e): Opsonin ; Agglutinin ; Amoebocytes ; Immunocytochemistry ; Lymnaea stagnalis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Monolayers of blood cells (amoebocytes) and sections of connective tissue and of amoebocyte pellets of the freshwater pulmonate gastropod Lymnaea stagnalis were stained immunocytochemically with antisera to snail agglutinin/opsonin. The presence of this substance was demonstrated light microscopically both in the cytoplasm and on the cell membrane of amoebocytes. This suggests that amoebocytes synthesize agglutinin/opsonin, and bear it at their surface as receptors for foreign materials.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 220 (1981), S. 223-230 
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Freeze-dried brain ; Fluid-fixed brain ; LHRH ; Somatostatin ; Neurophysin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunocytochemical staining of luteinizing hormone-releasing hormone (LHRH), somatostatin, and neurophysin was compared in rat brains fixed with 1) formalin, 2) Bouin's solution, 3) freeze-dried (FD), or 4) freeze-dried + paraformaldehyde vapor perfused (FDV). The distribution of LHRH fibers was similar in all preparations; however, beads of granular reaction product often appeared finer and more numerous in the median eminence of FD- and FDV brains. Positively stained LHRH perikarya were not observed in any of the preparations. In contrast, somatostatin-immunoreactive perikarya were present in the fluid-fixed and FD brains, although few were observed in FDV brains. Somatostatin-immunoreactive fibers were present in all preparations, but appeared most numerous in the median eminence of FD brains. Staining of neurophysin-containing perikarya and fibers was similar in all preparations. These observations suggest that the FD brain can provide a suitable tissue substrate for immunocytochemistry, demonstrating staining comparable to or surpassing that of more conventional preparations. However, staining of antigens in FD brain was not uniformly successful and may depend on stereochemical characteristics of each antigen as well as properties of the primary antisera used in the staining procedure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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