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  • 1975-1979  (3.846)
  • Cell & Developmental Biology  (2.718)
  • Engineering General  (946)
  • pharmacokinetics
  • Nuclear reactions
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  • 1
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of a single oral dose of muzolimine in cardiac failure (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 105-108 
    Details
    ISSN: 1432-1041
    Schlagwort(e): muzolimine ; cardiac failure ; pharmacokinetics ; high ceiling diuretics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of a new “high ceiling” diuretic, muzolimine (Bay g 2821), were investigated after a single oral dose of 40 mg in 7 patients with cardiac failure (Stages I–IV, New York Heart Association classification), and in 2 healthy subjects. Plasma concentrations peaked 1–3 h after administration and declined according to a two-compartment model. The α-phase (distribution phase) lasted until 12–16 h after administration and the mean t1/2α was 3.6 h (range 2.3–4.7) in patients, and 2.6 h (range 2.3–2.9) in healthy subjects. The mean t1/2β was 13.5 h (range 7.4–22.4) in the patients and 14.0 h (range 12.4–14.6) in healthy subjects. T1/2β was not correlated with the degree of heart failure or with the area beneath the plasma concentration curve, which varied three-fold. The renal clearance of muzolimine was in the range 2.7–15.3 ml · min−1 in 5 subjects in whom it was investigated. The pharmacokinetics of muzolimine appear not to be significantly altered by cardiac failure. The prolonged half-lives of the drug are probably responsible for the longer duration of diuretic action reported for muzolimine than for furosemide and bumetamide.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00609872
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  • 2
    Digitale Medien
    Digitale Medien
    Absorption of digoxin in severe right heart failure (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 115-120 
    Details
    ISSN: 1432-1041
    Schlagwort(e): digoxin ; right heart failure ; absorption ; absolute bioavailability ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The absorption of digoxin has been investigated in 8 patients before and after successful treatment of severe right heart failure.3H-digoxin 0.1 mg as a solution, and un-labelled digoxin 0.25 mg as a tablet, were given to fasted patients. Blood samples were taken at various time intervals up to 120 hours and urine was collected over the same period. The concentrations of labelled digoxin in plasma and urine were measured in a liquid scintillation counter, unlabelled digoxin was estimated by radioimmunoassay, and various pharmacokinetic parameters were calculated. There was no significant difference in the plasma concentration curves in severe right heart failure and after its successful treatment, nor did any of the calculated pharmacokinetic parameters change significantly. Therefore, inhibition of the absorption of digoxin appears unlikely. In an additional study to estimate absolute bioavailability two different groups of patients in severe right heart failure were given3H-digoxin 0.1 mg or unlabelled digoxin 0.25 mg i. v. and the pharmacokinetic parameters were compared with those from the previous study. The bioavailability of the3H-digoxin solution and of the digoxin tablet were in the same range as values previously published for healthy volunteers, and patients both with and without cardiac failure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00609874
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  • 3
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of quinidine related to plasma protein binding in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 187-192 
    Details
    ISSN: 1432-1041
    Schlagwort(e): quinidine ; plasma protein binding ; pharmacokinetics ; man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The disposition and plasma protein binding of quinidine after intravenous administration were studied in 13 healthy subjects. Plasma protein binding, expressed as the fraction of quinidine unbound ranged from 0.134–0.303 (mean 0.221). Elimination rate constant (β) varied from 0.071 to 0.146 h−1 (mean 0.113), and apparent volume of distribution (Vβ) varied from 1.39–3.20 l · kg−1β (mean 2.27). Total body clearance was 2.32–6.49 ml min−1 · kg−1. There was a positive linear correlation between the plasma fraction of unbound quinidine and both Vβ (r=0.885, p〈0.01) and total body clearance (r=0.668, p〈0.05). No significant correlation existed between the fraction of unbound quinidine in plasma and the elimination rate constant. The results show that both the apparent volume of distribution and total body clearance of quinidine are proportional to the unbound fraction in plasma. This implies that the total plasma concentration of quinidine at steady state will change with alterations in plasma binding, whilst the concentration of unbound compund and its elimination rate will remain unaffected.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563104
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  • 4
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of clorazepate in pregnant and non-pregnant women (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 175-180 
    Details
    ISSN: 1432-1041
    Schlagwort(e): clorazepate ; nordiazepam ; pregnancy ; pharmacokinetics ; intramuscular injection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A single dose of clorazepate 20 mg was injected i.m. in 7 pregnant and 7 non-pregnant women. Blood samples were collected for one week, and urine was collected for 24 h after the dose. The concentrations of clorazepate and its metabolite nordiazepam were determined by electron capture gas liquid chromatography. There was no difference between the two groups on physical examinations. Clorazepate was rapidly absorbed and the peak concentration was reached within 2h. Mean pharmacokinetic parameters for clorazepate were absorption half life 0.77h in pregnant women and 0.56h in non-pregnant women; elimination half life 1.3h in pregnant women and 2.0h in non-pregnant women; volume of distribution: 0.43 l · kg−1 in the pregnant women and 0.33 l · kg−1 in non-pregnant women. Nordiazepam reached its peak concentration within 12h after dosing; its mean half life of elimination was 180h in pregnant women and 60h in non-pregnant women. Within 24h, 1.3% of the clorazepate was recovered in urine from pregnant women and 7% in urine from the non-pregnant women.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563102
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  • 5
    Digitale Medien
    Digitale Medien
    Relationship between plasma concentration and effect of dantrolene sodium in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 203-209 
    Details
    ISSN: 1432-1041
    Schlagwort(e): dantrolene sodium ; spasticity ; twitch tension ; dose response ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Dantrolen sodium is a muscle relaxant, which is used in the treatment of spasticity. Although it is given chronically, little is known about its pharmacokinetic behaviour. The relationship between the effect of a single oral dose of dantrolene sodium and its plasma concentration in healthy volunteers was studied by measuring the effect on the twitch tension, and in spastic patients on the decrease in muscle hypertonia. On the twitch tension dantrolene gave a depression of 49.1±9.4% (±SD) within 1.15 and 3.45 h after ingestion of 100 mg. The mean maximal plasma concentration was 1.24±0.32 µg/ml (±SD). The effect and the plasma concentration were correlated. No relationship between the plasma concentration of dantrolene sodium and its effect could be established in patients, although definite activity in 6 out of 7 patients was observed after a single oral dose of 100 mg, and plasma concentration of dantrolene sodium greater than 0.3 µg/ml were consistently associated with better results than placebo treatment in 6 out of 7 patients.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00562062
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  • 6
    Digitale Medien
    Digitale Medien
    Pharmacokinetic and pharmacodynamic interactions of diazepam with different alcoholic beverages (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 263-270 
    Details
    ISSN: 1432-1041
    Schlagwort(e): diazepam ; alcoholic beverages ; plasma level ; pharmacokinetics ; co-ordination skills ; red wine ; white wine ; whisky
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Twenty paid healthy students ingested diazepam 10 mg 30 min after the administration of ethanol 0.8 g/kg. The alcoholic beverage used was varied in randomized double-blind experiments, which were repeated at one-month intervals. Psychomotor performance, plasma diazepam, and alcohol concentration in breath were measured 30, 60, 90 min and 2, 3, 4, 6 and 24 h after the ingestion of diazepam. Beer and white wine elevated the plasma level of diazepam and the effect lasted for up to 2 h. Whisky elevated the diazepam level for 90 min. Red wine did not affect it significantly. The alcohol-diazepam combination impaired tracking skills and oculomotor co-ordination and enhanced nystagmus, more than diazepam alone. Red wine produced a breath alcohol concentration higher than after white wine. More nystagmus was recorded after red wine and diazepam, although white wine led to a higher plasma diazepam concentration. It appears that simultaneous ingestion of alcohol and diazepam accelerates the absorption of diazepam. This pharmacokinetic alteration may not contribute much to the combined psychomotor effects of diazepam and alcohol, which were mainly due to pharmacodynamic interaction at receptor level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00608405
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  • 7
    Digitale Medien
    Digitale Medien
    Analysis of the pharmacokinetics of lithium in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 271-277 
    Details
    ISSN: 1432-1041
    Schlagwort(e): lithium ; litarex ; single dose ; multiple dose ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary An analysis of the single and multiple dose pharmacokinetics of lithium in 7 healthy volunteers is presented. A solution of lithium chloride was administered in single dose experiments and the same solution and a sustained release preparation were employed in multiple dose experiments, which were carried out at steady state. A fixed dose of 24 mmol was used in the single dose experiments and in the subsequent multiple dose experiments in the same subjects the same dose was administered once daily for a week. Distinct two-compartment characteristics were found, with a mean disposition rate constant (β) of 0.035 h−1±0.010 SD, corresponding to a mean biological half-life of about 19.8 h. The mean half-time of the distributory α-phase was about 1.15 h. The absorption of lithium from an orally administered solution took place with a half-time of about 0.15 h in the single dose experiments. The apparent volume of distribution of the central compartment (Vc) was 0.307 1 kg−1±0.046 SD, less than half that of Vde at equilibrium. Vdβ (Vdarea) was 0.8291 kg−1±0.184 SD and mean total body clearance was 27.6 ml kg−1 h−1±4.7 SD.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00608406
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  • 8
    Digitale Medien
    Digitale Medien
    Kinetics of canrenone after single and multiple doses of spironolactone (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 255-262 
    Details
    ISSN: 1432-1041
    Schlagwort(e): spironolactone ; canrenone ; fluorimetry ; high performance liquid chromatography ; linear kinetics ; saturation kinetics ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In Study I 20 normal volunteers received a single oral dose of spironolactone 100 mg. In Study II a further 20 normal volunteers were given first spironolactone 100 mg b.i.d. and subsequently spironolactone 100 mg once a day for a further 4 days. In Study III 5 normal subjects were given a single dose of spironolactone 500 mg. The concentration of canrenone in serum was determined both by fluorimetry and HPLC for 0–48 h in Study I, 120–168 h in Study II and 0–36 h in Study III. The total AUCs after the single 100 mg dose did not differ from the AUCs within the dosing interval during steady state. The half-lives of the terminal log-linear phases were almost identical (14.99±0.80 h and 15.69±0,80 h) when determined by fluorimetry, and were sligthly, but significantly (p〈0.01), longer when determined by HPLC — 20.14±1.62 and 18.71±1.04. The mean ratio of the specific AUC determined by HPLC and the fluorimetrically determined AUC was 0.3 after the single 100 mg dose. It did not differ from the corresponding value during steady state (0.34). In contrast, the ratio after the single 500 mg dose was approximately 50% higher. Fluorimetrically determined AUCs after 100 and 500 mg doses did not show dose-proportionality in contrast to the HPLC-determined AUCs. It was concluded that Canrenone contributes much less to the conventional fluorimetric determination than was previously assumed. It may not provide more than 1/10 and 1/4 of the antimineralocorticoid activity of spironolactone after single dose and multiple doses, respectively. Whereas linear kinetics apply after single and multiple 100 mg doses of spironolactone, after 500 mg saturation kinetics must be assumed with respect to metabolism. Thus, in bioavailability studies high doses of spironolactone should be avoided. For such studies the fluorimetric assay seems to be the appropriate bioanalytical method in spite of its lower specificity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00608404
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  • 9
    Digitale Medien
    Digitale Medien
    Haemodynamic effects and pharmacokinetics of a new selective beta1-adrenoceptor agonist, prenalterol, and its interaction with metoprolol in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 9-13 
    Details
    ISSN: 1432-1041
    Schlagwort(e): prenalterol ; metoprolol ; haemodynamics ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The haemodynamic effects of the selectiveβ 1-adrenoceptor agonist prenalterol were studied in healthy subjects before and after therapeutic doses of the selectiveβ 1-adrenoceptor blocker metoprolol. Plasma levels of the drugs were also determined in order to calculate certain pharmacokinetic variables. Intravenous infusion of prenalterol 0.13, 0.25 and 0.50 mg induced a dose-dependent decrease in total electromechanical systole (QA2) and pre-ejection period (PEP). The effect on left ventricular ejection time (LVET) was not significant. Increases in systolic blood pressure and heart rate were dose-dependent. Diastolic blood pressure did not change significantly. When metoprolol had been administered in a cumulative dose of 150 mg (mean maximal plasma level, 284 nmol/1) prenalterol had to be administered in doses that were twelve times higher than before theβ-blocker in order to induce the same haemodynamic effects. Prenalterol was rapidly distributed with an average half life of 8 min. This indicates that distribution equilibrium will be achieved within 30 min after intravenous administration. The overall elimination rate in the post-distributive phase corresponded to an average half life of 2.0 h.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563552
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  • 10
    Digitale Medien
    Digitale Medien
    Plasma and urinary levels of triamterene and certain metabolites after oral administration to man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 39-44 
    Details
    ISSN: 1432-1041
    Schlagwort(e): triamterene ; pharmacokinetics ; diuretic effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma and urinary levels of triamterene and two metabolites were measured using a specific method of analysis. Urinary excretion was completed after 48 h, which permitted a rough estimate of its half-life as longer than two hours. The areas under the curve were 672.5±160.3 and 1.311.3±399.1 µg/ml × h after the triameterene 150 mg and 300 mg p.o., respectively and correspondingly 4.2±1.4% and 3.7±0.6% of the dose were excreted as unchanged drug. The principal metabolite of triamterene found was the sulfate conjugate. The area under the curve of this metabolite amounted to 6.672±2.120 and 11.941±5.005 µg/ml × h after the of 150 mg and 300 mg triamterene doses, respectively. The urinary excretion of the metabolite varied between 25.0±4.0% and 17.5±3.5% of the dose after either dose. In healthy subjects an effect on sodium excretion was observed after a dose of 150 mg, whereas the potassium-retaining effect was observed only after the dose of 300 mg.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00644964
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  • 11
    Digitale Medien
    Digitale Medien
    Disposition pharmacokinetics of bezafibrate in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 31-38 
    Details
    ISSN: 1432-1041
    Schlagwort(e): bezafibrate ; hyperlipoproteinemia ; bioavailability ; pharmacokinetics ; GC-MS
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The disposition kinetics of bezafibrate, a newly developed drug of great lipid-lowering potency, were investigated in normal male subjects. Five male volunteers received14C-labelled bezafibrate orally in solution, and a further 10 were given the same dose (300 mg) of un-labelled drug as tablets. The concentration of bezafibrate in serum and urine from the latter was determined by GC, and in the former total radioactivity in serum, urine and feces was followed for 48 h, and urinary excretion products were analysed by TLC and GC-MS. Rapid absorption from the gastrointestinal tract led to peak serum levels 30 min and 2 h after administration of solution and tablets, respectively. Since approximately 95% of the administered14C-bezafibrate was excreted in urine within 48 h, and almost all the remainder was detected in feces, absorption can be regarded as complete after administration in solution. The relative optimal bioavailability from the tablets was also complete, since in both cases approximately 50% of the administered dose was detected as unchanged bezafibrate in urine within 24 h by GC in the tablet study, and by TLC in the solution study. Of the decomposition products, more than 20% of the dose was present as glucuronides and the remainder consisted of several more polar compounds, one of which was identified as a hydroxyderivative of bezafibrate. Since the apparent halflife of bezafibrate in serum was 2.1 h, this new drug possesses favourable pharmacokinetic features: rapid and complete absorption, even from tablets, combined with a conveniently short half-life, and clearance which is half renal (56 ml/min) and half metabolic (43 ml/min), giving a total clearance of 99 ml/min.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00644963
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  • 12
    Digitale Medien
    Digitale Medien
    Absolute bioavailability of quinidine in two sustained release preparations (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 45-48 
    Details
    ISSN: 1432-1041
    Schlagwort(e): quinidine ; slow release formulation ; pharmacokinetics ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The bioavailability of quinidine in two sustained release preparations A and B has been compared in three females and three males with i.v. administration of quinidine. The initial rate of oral absorption did not differ between the two drug preparations; the peak concentration was observed after 4 h both for A and B, but was significantly higher after B. A slower decrease in plasma concentration was observed after preparation A than B. Absolute bioavailability did not differ significantly between A (median value 78.4%) and B (median 87.1%). Drug absorption in vivo was in good agreement with the results of in vitro dissolution tests on both preparations. The slower decrease in plasma concentration found for the new sustained release form of quinidine should be of clinical advantage.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00644965
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  • 13
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of cephacetrile in patients undergoing haemodialysis (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 49-52 
    Details
    ISSN: 1432-1041
    Schlagwort(e): cephacetrile ; haemodialysis ; pharmacokinetics ; renal failure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of cephacetrile were studied after its administration as a single i.v. bolus injection of 15 mg/kg body weight to 11 patients with terminal renal inpairment undergoing haemodialysis for 6 h. A two-compartment kinetic model was used to describe the biphasic decrease in plasma concentration. The quantities of antibiotic in the central and peripheral compartments, and the amounts eliminated, were calculated for different times. During haemodialysis sessions, the average pharmacokinetic parameters of cephacetrile determined at the dialyser input were: α=5.03 h−1,β=0.458 h−1, K12=2.337 h−1, K21=1.996 h−1 K13=1.154 h−1, Vc=5.508 l, Vp=6.448 l, Vdss=11.956 l. As a function of the pharmacokinetic parameters of cephacetrile, a regimen of multiple doses was established for patients with terminal renal impairment, which will guarantee safe and effective concentrations of the antibiotic.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00644966
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  • 14
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of methadone during maintenance therapy: Pulse labeling with deuterated methadone in the steady state (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 53-57 
    Details
    ISSN: 1432-1041
    Schlagwort(e): methadone ; mass fragmentography ; pulse labeling ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A technique is presented for study of steady state kinetics of methadone using pulse labeling with deuterated methadone (d3) and mass fragmentography to measure both unlabeled and labeled methadone in blood. Seven subjects maintained on methadone for at least 10 months were admitted to a closed metabolic ward. The daily dose of unlabeled methadone (d0) was substituted by one dose of methadone-d3 and plasma levels of methadone-d0 and methadone-d3 were followed for 48 h using a precise (SD±5%) and sensitive (30 pmol/ml) mass fragmentographic technique. Plasma half-lives (t1/2) for both methadone-d0 and metadone-d3 were calculated from samples obtained 8–24 h following the dose of methadone-d3. The t1/2 of oral methadone-d3 was shorter (22±2 h) than that of methadone-d0 (52±20 h). The same pattern was observed after intravenous administration. The results indicate multiple pools of methadone in the body.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00644967
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  • 15
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of dihydroquinidine in congestive heart failure patients after intravenous quinidine administration (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 101-105 
    Details
    ISSN: 1432-1041
    Schlagwort(e): dihydroquinidine ; congestive heart failure ; intravenous administration ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of dihydroquinidine were studied in 8 patients with congestive heart failure following a 22 min intravenous infusion of a quinidine preparation that contained 5.9% dihydroquinidine as an impurity. Using a thin layer chromatography-fluorometric assay procedure for dihydroquinidine, the post-infusion plasma dihydroquinidine concentrations declined biexponentially. The half-life of the fast and slow dispositional processes was 4.42±1.81 min and 6.52±2.40 h, respectively. The central compartment volume for dihydroquinidine in these patients was 0.44±0.11 l/kg with an overall apparent volume of distribution of 1.14±0.38 l/kg. The computed values of total body plasma clearance of dihydroquinidine ranged from 1.29 to 2.69 ml/min/kg with a mean value of 1.94±0.60 ml/min/kg. In these patients, approximately 16% of the administered dihydroquinidine dose was excreted intact into the urine in 48 h. The estimated value of renal clearance was 0.314±0.129 ml/min/kg. When compared to control cardiac patients, the data showed that the apparent volume of distribution for dihydroquinidine is smaller in patients with congestive heart failure and as a result of this diminished volume, the clearance rate of dihydroquinidine was slower. The net effect of these differences was the production of higher plasma concentrations of dihydroquinidine in the heart failure group.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563115
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  • 16
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of cefoxitin in patients with normal or impaired renal function (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 119-124 
    Details
    ISSN: 1432-1041
    Schlagwort(e): cefoxitin ; renal impairment ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of cefoxitin have been determined after a single i.v. injection of 15 mg/kg body weight in 10 patients with normal renal function and 20 patients with varying degrees of renal impairment. The kinetics of the antibiotic followed an open two-compartment model. In patients with normal renal function the following pharmacokinetic parameters were found: $$\begin{gathered} \begin{array}{*{20}c} {\alpha = 8.66 h^{ - 1} } & {\beta = 1.21 h^{ - 1} } & {K_{12} = 3.47 h^{ - 1} } \\ \end{array} \hfill \\ \begin{array}{*{20}c} {K_{21} = 3.17 h^{ - 1} } & {K_{13} = 3.15 h^{ - 1} } & {V_c = 4.24 l.} \\ \end{array} \hfill \\ \begin{array}{*{20}c} {V_p = 4.87 l.} & { Vd_{ss} = 9.11 l.} \\ \end{array} \hfill \\ \end{gathered}$$ In the patients with renal impairment there was a significant decrease in $$\mathop \alpha \limits_, \mathop \beta \limits_, $$ K12, K21 and K13, and an increase in the apparent volume of distribution. The degree of plasma protein binding in patients with normal renal function was 73.6% and this was diminished in patients with renal impairment. A linear relationship between K13 of cefoxitin and creatinine clearance was demonstrated. The dosage regimen for patients with renal impairment should be adjusted by modifying the dosage interval whilst maintaining the amount administered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563118
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  • 17
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of metformin after intravenous and oral administration to man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 195-202 
    Details
    ISSN: 1432-1041
    Schlagwort(e): metformin ; biguanides ; pharmacokinetics ; absorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The kinetics of14C-metformin have been studied in five healthy subjects after oral and intravenous administration. The intravenous dose was distributed to a small central compartment of 9.9±1.61 ( $$\bar X$$ ±SE), from which its elimination could be described using three-compartment open model. The elimination half-life from plasma was 1.7±0.1 h. Urinary excretion data revealed a quantitatively minor terminal elimination phase with a half-life of 8.9±0.7 h. After the intravenous dose, metformin was completely excreted unchanged in urine with a renal clearance of 454±47 ml/min. Metformin was not bound to plasma proteins. The concentration of metformin in saliva was considerably lower than in plasma and declined more slowly. The bioavailability of metformin tablets averaged 50–60%. The rate of absorption was slower than that of elimination, which resulted in a plasma concentration profile of “flip-flop” type for oral metformin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00562061
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  • 18
    Digitale Medien
    Digitale Medien
    Kinetics of salicylates in blood and joint fluid (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 279-285 
    Details
    ISSN: 1432-1041
    Schlagwort(e): salicylate ; synovitis ; osteoarthritis ; arthritis ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Samples of blood and joint fluid from 30 patients who had taken buffered acetylsalicylic acid were examined for concentrations of total salicylates (TSA), acetylsalicylate (ASA) and salicylate (SA). The data were arranged in groups according to diagnosis of the joint disease. Analysis of the data did not show significant difference in the kinetics of TSA into blood. In groups the time to first appearance of 0.3 mg/l averaged 6.3 min for TSA; these values averaged 7.7 min for ASA and 10.9 min for SA. Close to maximum concentrations in blood averaged 18.9 mg/l for TSA, 3.3 mg/l for ASA, and 23.3 mg/l for SA. The time for first appearance of 0.3 mg/l of total salicylates in joint fluid ranged from 10 to 34 min with an average of 18.1 min; the values of ASA averaged 19.4 min and those of SA 21.9 min. The maximum concentration in joint fluid averaged 15.7 mg/l for TSA, 2.5 mg/l for ASA, and 14.5 mg/l for SA. Transport of salicylates from blood to joint fluid showed a pattern consistent with the type of joint disease. Support was found for the hypothesis that diffusion was the major factor in the movement of salicylates from blood to joint fluid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00608407
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  • 19
    Digitale Medien
    Digitale Medien
    Pharmacokinetic model based on circulatory transport (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 287-293 
    Details
    ISSN: 1432-1041
    Schlagwort(e): linear system theory ; perfusion model ; cardiac output ; pulmonary extraction ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Assessment of pharmacokinetics in terms of circulatory drug transport is proposed using the methods of linear system theory. In this model-independent approach drug distribution and disposition are characterized by the total extraction ratio, the mean residence time in the body and the volume of distribution at steady state. In analyzing concentration(c)-time(t) data, the procedure requires calculation only of the areas under the c(t)-and c(t)×t-curves to estimate kinetic parameters, and for prediction of the steady state concentration following continuous infusion or multiple doses. Pulmonary clearance of drugs is included in the theory.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00608408
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  • 20
    Digitale Medien
    Digitale Medien
    Absolute bioavailability of chlorthalidone in man: A cross-over study after intravenous and oral administration (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 35-50 
    Details
    ISSN: 1432-1041
    Schlagwort(e): chlorthalidone ; pharmacokinetics ; oral and i.v. doses ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Seven normal human volunteers each received a constant-rate infusion of chlorthalidone for 2 h, and the same (commonly 50 mg) single oral dose on separate occasions. The concentration of unchanged chlorthalidone was analyzed over a 100 to 220 h period in plasma, red blood cells, urine and faeces after both dosage forms. A three compartment model was required to describe the intravenous plasma concentrations in five of the subjects. A two compartment model sufficed to account for the decay of the oral plasma concentrations in all seven subjects. The mean plasma t1/2 after i.v. dosing was 36.5 h (±10.5 SD), and the mean plasma t1/2 after oral doses was 44.1 h (±9.6 SD). The mean red blood cell concentration t1/2 after i.v. doses was 46.4 h (±9.9 SD), and the mean red blood cell t1/2 after the oral doses was 52.7 h (±9.0 SD). The shorter i.v. half-live was not equally manifest in all subjects, being mainly apparent in three of them. In all cases the urinary excretion rate plots were parallel to the plasma concentration curves. As the faster decay after i.v. administration was not accompanied by increased renal clearance, the difference must have been due to non-renal mechanism. The mean total of 65.4 (±8.6 SD) % of the intravenous dose was excreted in urine over infinite time, whereas the mean total excretion after the oral dose was 43.8 (±8.5 SD) %. Faecal excretion ranged from 1.3–8.5% of dose in the i.v. study to 17.5–31.2% of dose in the oral study. The sum of the amounts present in urine plus faeces pointed strongly to an important metabolic route of elimination of chlorthalidone. Bioavailability estimates (F) from three sets of data were — a mean F of 0.61 from plasma concentrations, 0.67 from urinary excretion measurements and 0.72 from the erythrocyte concentrations. Simulations with a non-linear model indicated lesser validity of the estimate from erythrocyte concentrations. It was concluded that the average of plasma and urine data, F=0.64, yielded the best estimate of the oral availability of chlorthalidone 50 mg in man.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563556
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  • 21
    Digitale Medien
    Digitale Medien
    Disposition of guanethidine during chronic oral therapy (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 121-125 
    Details
    ISSN: 1432-1041
    Schlagwort(e): guanethidine ; chronic therapy ; urinary excretion ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma level and urinary excretion rate of guanethidine have been measured in 30 patients during oral maintenance therapy, and in 5 patients following discontinuation of therapy. A significant correlation was found between the daily average urinary excretion and the maintenance dose, although wide interindividual variation was noted among patients maintained on the same dose. A statistically significant correlation was also observed between the area under the plasma level curve during the dose interval and the oral maintenance dose. After discontinuation of chronic therapy, the half-life of 1.5 days of the initial phase of elimination was essentially in agreement with the half-life of almost 2 days determined in acute studies. In addition, a second phase of elimination with a half-life of 4 to 8 days was observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00609875
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  • 22
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of the placental transfer and distribution of clorazepate and its metabolite nordiazepam in the feto-placental unit and in the neonate (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 181-185 
    Details
    ISSN: 1432-1041
    Schlagwort(e): clorazepate ; nordiazepam ; pregnancy ; placental transfer ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Clorazepate 20mg was given i. m. to 49 mothers during the first stage of labour. The elimination of the drug was studied in 27 newborns produced by these mothers. The same dose was given to 13 women who underwent amniocentesis and to 7 women who were breast-feeding. “Total nordiazepam”, i.e. the sum of clorazepate and its metabolite nordiazepam, was determined by gas-liquid chromatography in maternal blood, umbilical cord blood (both arterial and venous), amniotic fluid and in milk. Clorazepate was found to cross the placental barrier slowly, but nordiazepam was transferred more rapidly. Nordiazepam was found in the milk and in the blood of neonates after breast-feeding had started.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563103
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  • 23
    Digitale Medien
    Digitale Medien
    Influence of food on the absorption of phenytoin in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 269-274 
    Details
    ISSN: 1432-1041
    Schlagwort(e): phenytoin ; food-intake ; bioavailability ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The influence of food intake on the absorption of phenytoin was examined in eight healthy volunteers, by study of single-dose kinetics following ingestion of phenytoin 300 mg either with a standardized breakfast or on an empty stomach. Blood samples were collected at regular intervals from 0 to 48 h, and serum concentrations of unmetabolized phenytoin were determined by gas chromatography. Serum concentrations of the major metabolite of phenytoin, 4-hydroxyphenytoin, were measured by mass fragmentography. Concurrent intake of food and phenytoin appeared to accelerate absorption of the drug from the formulation used, and the peak concentrations were significantly higher (mean increase 40%) in the postprandial than in the preprandial state. As reflected by the AUC (area under the curve), the amount of drug absorbed was increased during postprandial conditions, although the difference only reached borderline significance. It is suggested that phenytoin should always be taken in a defined relation to meals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00618516
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  • 24
    Digitale Medien
    Digitale Medien
    Pharmacokinetic, bioavailability and pharmacodynamic study of indobufen (K 3920), an inhibitor of platelet aggregation, after a single dose in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 323-327 
    Details
    ISSN: 1432-1041
    Schlagwort(e): indobufen ; platelet aggregation ; single dose ; bioavailability ; pharmacodynamics ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Six healthy volunteers received single iv and oral doses of 2-[p-(1-oxo-2-isoindolinyl)phenyl] butyric acid 100 mg (indobufen; K 3920), an inhibitor of platelet aggregation. Plasma levels and urinary excretion of the drug were determined by GLC. Collagen-induced platelet aggregation was assessed turbidimetrically at various intervals after administration. The plasma half-life of the drug was 7–8 h and more than 70% of the administered dose was recovered within 48 h in urine, as unchanged drug and as the glucuronide of indobufen. After oral administration of tablets of two different formulations, the drug was completely absorbed, but one formulation showed faster absorption. The maximal inhibitory effect on platelet aggregation was observed 1 to 4 h after iv administration, and it had decreased by 8 h. After tablets, peak effect and the time of the peak were similar, but activity was significantly prolonged, in accordance with the higher plasma levels found at 8 h. The data suggest that the effect of indobufen on platelets is reversible, and that for this drug platelets behave as a compartment that slowly equilibrates with plasma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00558435
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  • 25
    Digitale Medien
    Digitale Medien
    A pharmacokinetic study of neostigmine in man using gas chromatography-mass spectrometry (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 367-371 
    Details
    ISSN: 1432-1041
    Schlagwort(e): myasthenia gravis ; neostigmine ; gas chromatography-mass spectrometry ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary To permit rational evaluation of the empirical pharmacotherapy of myasthenia with cholinesterase inhibitors, a sensitive and selective method for the determination of neostigmine has been developed. Analysis is based on ion-pair extraction of neostigmine into methylene chloride and determination by gas chromatography-mass spectrometry (chemical ionization). As neostigmine was found to be metabolized in plasma in vitro, deuterated (d6) neostigmine was immediately added to the plasma sample as the internal standard. The limit of quantitation of the method was about 1 ng/ml (∼ 3nmol/l). The kinetics following i. v. administration were studied in four patients, who received neostigmine 2.5–3.0 mg iv to antagonize pancurone administered during anaesthesia. Elimination was rapid with a half-life t1/2 (β-slope) of 0.89±0.05 h (mean ± SE). The volume of distribution was 1.08±0.11 l/kg and plasma clearance was 0.84±0.04 l/kg/h. In three fasting myasthenic patients plasma concentrations of neostigmine were followed for 5 h after a single oral dose of 30 mg. Considerable interindividual differences in absorption were expressed in the peak concentrations, which occurred 1–2 h following drug ingestion. The bioavailability of neostigmine was estimated to be 1–2% of the ingested dose. Neostigmine concentration in plasma was found to differ considerably (up to forty-fold) between myasthenic patients on their ordinary dose-schedules of cholinesterase inhibitors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00558442
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  • 26
    Digitale Medien
    Digitale Medien
    Cyclobarbital as a test substance for oxidative drug metabolism in man. Findings in neuropsychiatric patients (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 433-441 
    Details
    ISSN: 1432-1041
    Schlagwort(e): cyclobarbital ; barbiturates ; pharmacokinetics ; drug interaction ; volunteers ; patients
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The disappearance of cyclobarbital from plasma has been followed in healthy volunteers and in neurological and psychiatric patients after oral administration of one tablet of Phanodorm®, containing cyclobarbital calcium 200 mg. Plasma levels were measured by a thin-layer chromatographic method with in situ densitometry. The average t1/2 in healthy female and male volunteers was 13.3 h, and with the assumption of complete availability a mean distribution coefficient of 0.69 l/kg−1 and a clearance of 40.4 ml/min−1 were calculated. Repeated experiments in seven volunteers revealed good reproducibility of all values. When the healthy volunteers were combined with a group of untreated epileptics, a dependence of t1/2 and of the apparent volume of distribution on age was found, while clearance did not change with increasing age (range 17–54 years). Long half-lives caused by low clearance values were observed in several individuals with moderate obesity. No consistent change in cyclobarbital kinetics followed acute exposure of volunteers to alcohol or on treatment of neurological patients with carbamazepine. Patients under treatment with perazine exhibited more or less normal kinetic values. In terms of drug interaction, cyclobarbital differs from phenazone in several respects, and so it may prove a useful additional substance for measurement of the rate of drug oxidation in humans.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00561744
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  • 27
    Digitale Medien
    Digitale Medien
    Single and chronic dose pharmacokinetic studies of sodium valproate in epileptic patients (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 23-29 
    Details
    ISSN: 1432-1041
    Schlagwort(e): valproate ; epilepsy ; pharmacokinetics ; drug interaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In four refractory epileptic patients, peak plasma levels of sodium valproate occurred within 1.5 to 3 h after a single oral dose of valproate and the decline in plasma levels followed a monoexponential course with a t1/2 of 11.4 ± 0.1 h. The mean value for apparent volume of distribution was 0.176 ± 0.013 l/kg and for total plasma clearance 0.0106 ± 0.0009 l/h/kg. Steady state plasma levels were predicted using the method of superposition utilizing pharmacokinetic parameters determined following a single dose of valproate and were 78–123% of the predicted values for two patients receiving valproate alone, and 37–64% of the predicted values for the two patients receiving carbamazepine in addition to valproate. In a further group of 20 patients the mean daily doses of valproate for 8 patients receiving valproate alone (25.4 ± 4.9 mg/kg) was significantly less than those for the 12 patients receiving concomitant anticonvulsant therapy (41.6 ± 12.3 mg/kg) (p〈0.005). In addition, the steady state predose plasma levels of valproate were significantly higher in the valproate alone patients (90.3 ± 8.7 µg/ml) compared to the patients receiving additional anticonvulsants (75.3 ± 13.8 µg/ml) (p〈0.01). The higher dose requirements of valproate and lower predose and steady state plasma levels for those patients on multiple anticonvulsants indicate an interaction between valproate and other anticonvulsants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00644962
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  • 28
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of theophylline in young children with asthma: Comparison of rectal enema and suppositories (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 133-139 
    Details
    ISSN: 1432-1041
    Schlagwort(e): theophylline ; asthma ; pharmacokinetics ; children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Six children, aged 2 months – 4 years, received theophylline 5–6 mg/kg intravenously. Its disposition could be described by a two-compartment open model, the mean serum half life (t1/2 β) was 3.75 h, i. e., shorter than in adults, but there was a considerable interindividual variation (1.8–7.0 h, in one patient 13.3 h). Thirteen children (2 months – 4 years) received theophylline suppositories in a dose of 3.8–5.0 mg/kg, and ten (6 months – 4 years) in a dose of 8.4–14.5 mg/kg. Absorption was slow (mean half-time 43 min), incomplete and variable (biological availability 8–100%, mean 80%). Only four of the patients given the higher dose and none given the lower dose reached a therapeutic serum concentration (10–20 µg/ml). Nine children (6 months – 4 years) received rectal enemas of theophylline 4.1–9.2 mg/kg. Absorbtion was rapid (mean half-time 5.5 min) and biological availability averaged 100%. Six patients reached a serum concentration within the therapeutic range. Using the mean values of the calculated pharmacokinetic parameters, rectal enemas providing a dose of theophylline of 6–8 mg/kg t. i. d. were computed to give serum concentrations between 8–20 µg/ml, without producing too high a level during the absorption phase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563120
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  • 29
    Digitale Medien
    Digitale Medien
    Prazosin, pharmacokinetics and concentration effect (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 177-181 
    Details
    ISSN: 1432-1041
    Schlagwort(e): prazosin ; alpha receptor blockade ; blood pressure ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics and effects of prazosin have been studied after intravenous and oral dosing (1 mg) to 6 normal male volunteers. The mean terminal (β) half-life was 2.9 h after intravenous and oral routes. Oral bioavailability was 56.9%. The effects of prazosin on blood pressure were more pronounced after intravenous than oral administration, and the hypotensive effect greater on erect blood pressure. There was a significant correlation (P〈0.02) between the fall in blood pressure and the plasma drug concentration after intravenous prazosin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00562058
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  • 30
    Digitale Medien
    Digitale Medien
    Timolol pharmacokinetics and effects on heart rate and blood pressure after acute and chronic administration (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 243-249 
    Details
    ISSN: 1432-1041
    Schlagwort(e): timolol ; beta blockade ; pharmacokinetics ; pharmcodynamics ; acute administration ; chronic administration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics and effects of various oral doses of timolol administered either acutely or after chronic medication for 7 days were studied in healthy volunteers. After acute administration of timolol maximum plasma concentrations were attained within 1–2 h and thereafter declined exponentially with time. The mean apparent half-life of elimination from plasma was 2.5 h and was independent of dose. Area under the plasma concentration-time curve (AUC) was proportional to the orally administered dose. Plasma concentrations, apparent elimination half-life and AUC were not altered after one week of chronic administration. The effect of timolol on heart rate and blood pressure response to three sequentially increasing ‘steady state’ work loads were studied. After acute administration of timolol maximum reduction of systolic blood pressure, resting heart rate, and the different parameters of the work-heart rate (or blood pressure) relationships were produced by 5 mg timolol. Increasing the dose prolonged the duration over which these variables were reduced. The relationship between timolol plasma concentration and inhibition of different parameters of the exercise response was hyperbolic with half maximum inhibition at concentrations of about 3–4 ng/ml of timolol and maximum inhibition above 30 ng/ml. Maximum drug effects and duration of action of timolol on the different variables were similar after acute and chronic administration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00608402
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  • 31
    Digitale Medien
    Digitale Medien
    Food-induced reduction in bioavailability of atenolol (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 327-330 
    Details
    ISSN: 1432-1041
    Schlagwort(e): atenolol ; food intake ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The influence of food intake on the bioavailability of the beta-adrenoceptor blocker atenolol was assessed by measurement of its single-dose kinetics in ten healthy volunteers, who took 100 mg both in the fasting state and together with a standardized breakfast. Food intake significantly shortened the time to reach peak concentration (2.7 h vs 1.5 h), but caused a significant reduction in AUC values, the mean decrease being 20%. The elimination half-life was unaffected. Atenolol, which is relatively hydrophilic, is incompletely absorbed in the fasting state, and escapes first-pass metabolism. The present findings indicate that food intake causes further impairment of its absorption, even though the absorption rate may initially be enhanced. This contrasts with previous observations on the more lipophilic beta-adrenoceptor blockers propranolol and metoprolol.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00605630
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  • 32
    Digitale Medien
    Digitale Medien
    Multicompartment pharmacokinetics of netilmicin (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 331-334 
    Details
    ISSN: 1432-1041
    Schlagwort(e): netilmicin ; radioenzymatic assay ; drug accumulation ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of a single dose of netilmicin (NM) was studied in 6 healthy volunteers. Elimination of the drug was followed in serum and urine for 24 h and 72 h, respectively. NM concentrations were measured with a modified radioenzymatic assay. A three compartment open model was employed to calculate the pharmacokinetic parameters. Following the rapid initial distribution, biphasic elimination with half lives of 1.99 h (t1/2β) and 36.89 h (t1/2γ) was demonstrated. Measurable amounts of NM were excreted in the urine for up to 72 h. The volume of distribution at steady-state (Vdss) of 0.68 l/kg was 3 to 4 times larger than previously reported for this antibiotic. NM plasma clearance was 91 ml/min and the renal clearance was 67 ml/min. The data indicate that on repetitive dosing the amount of drug in the body would be considerably underestimated if the prolonged terminal elimination phase were not taken into account. During prolonged treatment, accumulation of NM in renal and other tissues is likely to occur, as has been described for other aminoglycosides. The possible consequences of this pharmacokinetic behaviour are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00605631
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  • 33
    Digitale Medien
    Digitale Medien
    Bioavailability and pharmacokinetics of cimetidine (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 335-340 
    Details
    ISSN: 1432-1041
    Schlagwort(e): cimetidine ; enterohepatic circulation ; irregular absorption ; bioavailability ; pharmacokinetics ; volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The bioavailability and pharmacokinetics of cimetidine have been studied in healthy volunteers after administration of single intravenous (100 mg) and oral doses (100, 400 and 800 mg). After i.v. administration, the kinetics of cimetidine could be described by a linear, two compartment open model. Substantial variation in half-life was observed between subjects, with a mean value of 2.1 h (range 0.9–4.7). Cimetidine had a low hepatic extraction ratio and a high total plasma clearance, due to extensive urinary excretion of unchanged drug. After oral administration, the plasma concentration vs time curves in most subjects exhibited two marked peaks, an observation that seemed to be constant within individuals and was independent of dose. Bioavailability, estimated as the area under the plasma concentration vs time curves (AUC), after oral doses as compared to the intravenous dose, in most cases exceeded 100%. There was no correlation between bioavailability estimated as AUC and as urinary excretion of unchanged drug. These observations may indicate an enterohepatic circulatory mechanism, predominantly after oral administration. Both unchanged drug and its sulphoxide metabolite appear to be excreted in bile. The latter was shown in vitro to be reduced to cimetidine by fecal bacteria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00605632
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  • 34
    Digitale Medien
    Digitale Medien
    The disposition of intravenous doxapram in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 411-416 
    Details
    ISSN: 1432-1041
    Schlagwort(e): doxapram ; intravenous infusion regimen ; pharmacokinetics ; data-point weighting ; healthy subjects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of intravenous doxapram in healthy individuals is consistent with a three-compartment open model. Doxapram was administered by bolus injection (1.5 mg · kg−1) and by intravenous infusion (6.5 mg · kg−1 for 2 h) to 5 subjects on separate occasions. There was no significant difference in mean terminal plasma half-lives (355 and 448 min) or in mean total body clearances (5.9 and 5.6 ml · min−1 · kg−1) following i. v. bolus injection or infusion respectively. In 3 subjects plasma doxapram concentrations during and after i. v. infusion agreed with those predicted from pharmacokinetic values obtained from the bolus injection study. Since mean steady-state concentrations (9.9 µg · ml−1) would be reached only after an extended interval (mean 15.2 h), a variable-rate infusion regimen was calculated to produce and maintain a concentration of 2 µg · ml−1 from 15–25 min onwards. A regimen in which the infusion rate is reduced step-wise is recommended to achieve early near-constant plasma doxapram concentrations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00568202
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  • 35
    Digitale Medien
    Digitale Medien
    Plasma levels and negative chronotropic effect of metoprolol following single doses of a conventional and sustained-release formulation (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 97-103 
    Details
    ISSN: 1432-1041
    Schlagwort(e): metoprolol ; tachycardia ; healthy subjects ; conventional tablets ; slow release tablets ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Plasma levels and associated reduction in exercise-induced tachycardia have been examined following the administration of single doses of metoprolol in conventional and slow-release tablets at different times to six healthy male subjects. The study was carried out in two parts. Initially, the tablets were given at 9 a. m. and the subjects were studied up to 14 h and then at 24 h. Subsequently, the same doses were given at 9 p. m. and the subjects were studied 12–24 h after drug administration (i. e. 9 a. m.–9 p. m. the next day). After giving the slow-release tablets the peak plasma levels were significantly lower but the drug persisted in the plasma at higher levels than after the conventional tablet. However, the beta-blocking effect was comparable from the two dosages. The results obtained for the period 12–24 h after the evening dose differed from the corresponding values after morning administration in that the plasma levels were higher and the betablocking effects more marked. Furthermore, the half-life values calculated from these data were significantly longer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00609871
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  • 36
    Digitale Medien
    Digitale Medien
    Oral absorption of cimetidine and its clearance in patients with renal failure (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 153-157 
    Details
    ISSN: 1432-1041
    Schlagwort(e): cimetidine ; renal failure ; elimination half life ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma concentration curve after a single oral dose of cimetidine 200 mg was followed in 27 patients with varying degrees of chronic renal failure (creatinine clearance 1–52 ml/min) and in 46 patients with normal serum creatinine. Compared to the latter patients, the plasma concentration was higher and the elimination rate was slower in all uraemic subjects, including a group with moderate renal impairment. The preliminary recommendations of dosage for patients with a creatinine clearance below 5 ml/min, and for patients on regular haemodialysis, is cimetidine 200 mg every 12 h, 5–15 ml/min 200 mg every 12 to 8 h, 15–30 ml/min 200 mg every 8 h and 30–52 ml/min 200 mg every 6 h.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563098
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  • 37
    Digitale Medien
    Digitale Medien
    Human pharmacokinetics of nitrazepam: Effect of age and diseases (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 163-170 
    Details
    ISSN: 1432-1041
    Schlagwort(e): nitrazepam ; epilepsy ; age ; disease ; plasma concentration ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Plasma concentrations of nitrazepam were measured by gas-liquid chromatography in: young healthy volunteers, in geriatric and psychiatric patients and in epileptic children. The disposition of nitrazepam was described in terms of a two-compartment open model. After a single oral dose of nitrazepam 5 mg the most prominent differences between the experimental groups were in the β-phase half-life-mean 29 h in the young volunteers and 40 h in geriatric patients, and in the apparent volume of distribution during the β-phase of 2.4 vs 4.8 l/kg. Total plasma clearance and the average steady state concentration in both groups were equal. The plasma level rose at a rate proportional to the β-phase half-life, and so, they were achieved more rapidly in the young than in the old subjects (3.5 vs 7.5 d). No change in steady-state level or in the half-life of nitrazepam were found during long term treatment, which indicates lack of enzyme induction or inhibition. In 95% of the epileptic children with a good to fair clinical response, the plasma concentration of nitrazepam was 40–180 ng/ml (mean 114 ng/ml). As all of the patients were on combined antiepileptic therapy, no attempt was made to correlate plasma level with therapeutic response.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00563100
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  • 38
    Digitale Medien
    Digitale Medien
    Blood level of cimetidine in relation to age (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 257-261 
    Details
    ISSN: 1432-1041
    Schlagwort(e): cimetidine ; H2-receptor antagonist ; aging ; single dose ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The blood level versus time curve for unchanged cimetidine after a 200 mg oral dose has been determined in 20 apparently healthy subjects, ranging from 22 to 84 years of age. A significant relationship between the area under the curve (AUC) and age was found (r=0.81; P〈0.001). The peak concentrations of cimetidine were significantly inversely related to body weight (r=−0.71; P〈0.001). The age-related increase in bioavailability of oral cimetidine, as measured by AUC, was probably due to decreased total clearance of the drug, which resulted from the opposed changes (by themselves not significant) of distribution volume towards a decrease and of half-life towards an increase with age. Reduction in the standard oral dose of cimetidine by one third to one half should be feasible in the elderly without loss of efficacy, and it may be advisable in order to obviate extreme individual responses that may occur in this population.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00618514
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  • 39
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of bromocriptine during continuous oral treatment of Parkinson's disease (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 275-280 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Parkinson's disease ; bromocriptine ; pharmacokinetics ; plasma concentration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma kinetics of bromocriptine (BCT), a long-acting dopamine agonist, was studied in twelve patients with Parkinson's disease, using a newly developed gas chromatographic method of analysis. Each patient received BCT for at least three weeks in a constant but different dose regimen. Concomitant treatment with 1-DOPA was not allowed. During a 6-day hospitalization period, a blood sample was taken immediately before the afternoon dose at 14.00 h (Cmin) to determine the steady-state level. On the 6th day blood samples were collected every hour during two 8 h dose intervals. The results showed a significant correlation between the mean values of the AUC and the Cmin. First order elimination kinetics appeared to be followed by BCT, at least for the plasma concentrations commonly found. Considerable inter-individual variation was demonstrated both for the dose/plasma concentration ratio and for calculated plasma clearances. No serious side-effects were observed during the investigation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00618517
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  • 40
    Digitale Medien
    Digitale Medien
    Indobufen (K 3920), a new inhibitor of platelet aggregation: Effect of food on bioavailability, pharmacokinetic and pharmacodynamic study during repeated oral administration to man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 329-333 
    Details
    ISSN: 1432-1041
    Schlagwort(e): indobufen ; platelet aggregation ; food effect on bioavailability ; repeated administration ; pharmacodynamics ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effect of food on bioavailability of indobufen tablets was investigated in 6 healthy volunteers. Subsequently, the same subjects took 100 mg b.i.d. for 7 days. Plasma levels and urinary excretion of indobufen were determined by GLC. Platelet aggregation induced by several concentrations of adrenaline was determined turbidimetrically at various times after the first and last doses. The absorption of indobufen tablets was not substantially impaired by the presence of food in the GI tract, although peak plasma levels and AUCs were slightly reduced after food. Pharmacokinetic analysis of plasma and urinary levels of indobufen did not indicate any change in drug disposition after repeated dosing. Adrenaline-induced platelet aggregation was markedly inhibited for up to 12 h after the first dose and the intensity and duration of this effect did not change after repeated administration. A twice-daily dosing appears suitable for clinical trials.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00558436
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  • 41
    Digitale Medien
    Digitale Medien
    Clofibrate disposition in renal failure and acute and chronic liver disease (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 341-347 
    Details
    ISSN: 1432-1041
    Schlagwort(e): clofibrate ; chlorophenoxyisobutyric acid ; disposition ; hepatitis ; cirrhosis ; renal failure ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The disposition of clofibrate over 96 hours was observed following single oral dose in six patients with acute viral hepatitis, six patients with liver cirrhosis, seven patients with renal insufficiency, and six control subjects. No parameter of the disposition of CPIB (active form of clofibrate) was significantly altered in acute hepatitis. In liver cirrhosis, the mean plasma half-life was unchanged compared to controls (20.9 vs. 17.5 h), but plasma clearance of the non-protein bound drug was reduced (115 vs. 243 ml×min−1), plasma protein binding was reduced (92.8 vs. 97.2 percent), and the apparent volume of distribution was increased (0.20 vs. 0.141×kg−1). In renal insufficiency plasma half-life was prolonged 2 to 6-fold, depending on the degree of renal impairment. Total plasma clearance (3.4 vs. 7.1 ml×min−1) and plasma clearance of the unbound drug (81 vs. 243 ml×min−1 were reduced in patients with renal failure, the clearance of the unbound drug being inversely correlated with the serum creatinine concentration. Renal failure was also associated with decreased protein binding and an increased volume of distribution of CPIB, and with reduced urinary excretion of CPIB and its glucuronide metabolite. The dose of clofibrate should be halved in patients with cirrhosis. In renal insufficiency, the dose should be adjusted according to the individual serum creatinine level: only 10 to 15% of the usual weekly dose should be given in complete renal failure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00558438
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  • 42
    Digitale Medien
    Digitale Medien
    The protein binding of methotrexate by the serum of normal subjects (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 363-366 
    Details
    ISSN: 1432-1041
    Schlagwort(e): methotrexate ; protein binding ; ultrafiltration ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The protein binding of methotrexate by serum from eight normal volunteers was assessed by continuous ultrafiltration at pH 7.4 and 37°C. Methotrexate concentrations were measured by radioimmunoassay and the data analysed by the method of Scatchard. The major binding protein was albumin which bound 87.3% of the drug in serum. Analysis of the Scatchard plots indicated two distinct groups of binding sites. Class I was found to have 0.16±0.05 (S D) binding sites with an intrinsic association constant of 71.15±35.98 (S D)×104 M−1: Class II had 2.01±0.93 (S D) binding sites and an affinity of 0.18±0.15×104 M−1. No great change in the percentage of methotrexate bound occurred until the total concentration of the drug exceeded 50 µMol 1−1.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00558441
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  • 43
    Digitale Medien
    Digitale Medien
    Lorcainide infusion in the treatment of ventricular premature beats (VPB) (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 1-6 
    Details
    ISSN: 1432-1041
    Schlagwort(e): lorcainide ; ventricular premature beats ; plasma levels ; pharmacokinetics ; side effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma level and antiarrhythmic effect of lorcainide (R 15889) have been investigated in 15 patients with ventricular premature beats (VPB). Therapy was initiated with an intravenous dose of 1.9 mg/kg given over 10 min, followed by a constant infusion of 0.18 mg/kg/h for 24 h. In 8 patients the corresponding doses were increased to 2 mg/kg and 0.27 mg/kg/h. After the intravenous doses patients were treated orally with 100 mg tid for 6–7 days. The two dosage regimens were selected so as to achieve theoretical steady-state plasma levels (css) of 200 and 300 ng/ml, respectively. The combined intravenous treatment approached (181 ± 6.8 ng/ml and 273±28.5 ng/ml, respectively) the desired css within 2 to 4 h. During the oral administration, the minimal plasma concentrations following the lower intravenous dose (184±18 ng/ml) were significantly (p=0.0001) lower than after the higher intravenous dose (264±20.5 ng/ml). The dealkylated metabolite of lorcainide was not detectable after the intravenous doses, but it accumulated during oral treatment, when its concentration exceeded that of the parent compound. In 5 of the 7 patients receiving the lower dose VPB were effectively reduced. However, in only 4 of the 8 patients on the higher dosage schedule could a significant antiarrhythmic effect be demonstrated. In addition, side effects were observed in 6 of the subjects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00644958
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  • 44
    Digitale Medien
    Digitale Medien
    Influence of the defective metabolism of sparteine on its pharmacokinetics (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 189-194 
    Details
    ISSN: 1432-1041
    Schlagwort(e): sparteine ; pharmacogenetic defect ; defective metabolism ; pharmacokinetics ; renal excretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Sparteine is metabolized by N1-oxidation, which in some subjects is defective. The defect has a pronounced effect on the kinetics of the drug. In non-metabolisers elimination of sparteine proceeds entirely via renal excretion by a capacity-limited process, 99,9% of the dose being excreted as unchanged drug. In metabolisers the drug is mainly eliminated by metabolic degradation. Pronounced differences in β-phase half-life and total plasma clearance were observed between metabolisers (156 min; 535 ml · min−1) and nonmetabolisers (409 min; 180 ml · min−1).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00562060
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  • 45
    Digitale Medien
    Digitale Medien
    Single- and multiple-dose kinetics of oral lorazepam in humans: The predictability of accumulation (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 159-179 
    Details
    ISSN: 1573-8744
    Schlagwort(e): lorazepam ; benzodiazepines ; pharmacokinetics ; drug accumulation ; antipyrine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Six healthy volunteers participated in single- and multiple-dose pharmacokinetic studies of oral lorazepam. Following single 4-mg oral doses, peak plasma lorazepam concentrations ranging from 40 to 70 ng/ml were reached within 3 hr of the dose. Values of absorption half-life averaged 25min (range 10.3–42.7min), and elimination half-life (t 1/2β ) averaged 14.2 hr (range 8.4–23.9 hr). During 15 consecutive days of 3 mg per day administered in divided doses, accumulation to the steady-state condition was complete within several days of the initiation of therapy. Values of accumulation half-life (mean 21.1 hr) were slightly longer than t 1/2β , and the two were not well correlated. Observed accumulation ratios (mean 1.88) were very close to those predicted from the single-dose study (mean 1.77), but the correlation between the two (r=0.51) was not significant in the small sample size. “Washout” half-life values (mean 14.9 hr) were highly correlated with t 1/2β (r=0.92). Clearance of a single intravenous dose of antipyrine determined prior to the multiple- dose lorazepam study (mean 0.86 ml/min/kg) was essentially identical to that determined after the study (mean 0.87 ml/min/kg). Overall, the rate and extent of lorazepam accumulation during multiple dosage were reasonably well predicted by the single-dose kinetic study. However, accurate prediction for any specific individual was not always achieved. Stimulation or inhibition by lorazepam of its own clearance probably does not explain imprecise prediction, since single-dose t 1/2β .
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059736
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  • 46
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of digoxin: Relationship between response intensity and predicted compartmental drug levels in man (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 47-61 
    Details
    ISSN: 1573-8744
    Schlagwort(e): digoxin ; pharmacokinetics ; response kinetics ; three-compartment model ; serum digoxin kinetics ; systolic time intervals ; radioimmunoassay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A study designed to investigate the relationship between the pharmacokinetics of digoxin and a measure of its pharmacological effect has been conducted. Serum digoxin concentrations and systolic time intervals were measured concurrently in 12 normal male volunteers following a 1.0 mg i.v. bolus injection. The averaged serum digoxin concentration- time and response-time data were analyzed pharmacokinetically using a three-compartment open model and nonlinear least- squares fitting. When only the serum level-time data were analyzed, a close relationship was found between calculated digoxin levels in the slowly distributing (deep) peripheral compartment and response of the heart to digoxin, as measured by changes in the QS2 index δQS2I. Although it was not possible to distinguish clearly a linear from a nonlinear relationship between digoxin levels in the deep compartment and δQS2I, the nonlinear relationship gave the best overall fit when both serum digoxin and δQS2I data were fitted simultaneously. The simultaneous fityielded a total body clearance of digoxin of 3.6 ml/min/kg and a terminal t1/2 of 42 hr.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059440
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  • 47
    Digitale Medien
    Digitale Medien
    Kinetics of biotransformation of clonazepam to its 7-amino metabolite in the monkey (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 87-95 
    Details
    ISSN: 1573-8744
    Schlagwort(e): clonazepam ; in vivo biotransformation ; 7-amino metabolite ; pharmacokinetics ; monkeys ; anticonvulsants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The pharmacokinetic behavior of the 7-amino metabolite of clonazepam administered exogenously and formed endogenously from the parent drug was studied in a group of rhesus monkeys using constant rate intravenous infusions. Plasma levels of the 7-amino metabolite and/or clonazepam were determined with a GC-CI-MS method. The biological half-life of the 7-amino metabolite (2.2 ± 1.0 hr) was shorter than that of clonazepam (4.9 ± 0.2 hr). Total body clearance of the metabolite (0.83 ± 0.16 liters/hr/kg) was larger than that of the parent drug (0.55 ± 0.09 liters/hr/kg). The kinetics of in vivo biotransformation were described by a two- compartment model in which formation and disposition of the metabolite follow first-order processes. The fraction of a dose of clonazepam appearing in the systemic circulation as 7-amino metabolite was 0.70 ± 0.30. This value may underestimate the actual fraction formed, if the metabolite is susceptible to first- pass metabolism following in situ formation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059443
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  • 48
    Digitale Medien
    Digitale Medien
    Attenuation of furosemide's diuretic effect by indomethacin: Pharmacokinetic evaluation (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 265-274 
    Details
    ISSN: 1573-8744
    Schlagwort(e): furosemide ; indomethacin ; prostaglandin ; pharmacokinetics ; pharma-codynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The pharmacokinetics and pharmacodynamics of intravenous furosemide, 40 mg, were studied in four normal males in a crossover fashion with and without indomethacin pretreatment. In each study 16 plasma and 10 urine samples were collected over 24 hr. Fluid and electrolyte urinary losses were replaced orally throughout the study. Unchanged furosemide and indomethacin were measured using HPLC; urinary sodium was measured by flame photometry. Pretreatment with indomethacin resulted in increased and prolonged furosemide plasma levels, increased area under the curve, decreased plasma clearance, decreased renal clearance, increased half-life, no change in volume of distribution, and decreased sodium excretion and urine volume. Analysis of sodium excretion rate with time shows that the inhibiting effect of indomethacin was greater during the first 2 hr than at later times.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01060017
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  • 49
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of phenylethylacetylurea (pheneturide), an old antiepileptic drug (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 453-462 
    Details
    ISSN: 1573-8744
    Schlagwort(e): pheneturide ; antiepileptics ; pharmacokinetics ; TLC-UV densitometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The pharmacokinetics of pheneturide (a decarboxylation product of phenobarbital), used to prevent psychomotor seizures for many years, was studied in normal human volunteers. To measure the drug in plasma and urine, a highly sensitive and reproducible thin-layer chromatography-reflectance spectrophotometric assay was developed. The results show that pheneturide follows first-order kinetics in the dose range studied. Its half-life after single doses is 54 hr (range 31–90), and its total body clearance (100% nonrenal) is 2.6 liters/hr (range 1.73–3.59). After repetitive administration, half-life is 40 hr (but clearance remains unchanged because of a lower volume of distribution). Because of the long half-life, repetitive administration results in a continuous steady-state level and makes this drug (kinetically) ideal for long-term use.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01062387
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  • 50
    Digitale Medien
    Digitale Medien
    Plasma levels and β-blocking effect of α-hydroxymetoprolol—Metabolite of metoprolol—in the dog (1979)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 7 (1979), S. 471-479 
    Details
    ISSN: 1573-8744
    Schlagwort(e): metoprolol ; α-OH-metoprolol ; active metabolites ; pharmacokinetics ; β- blocking effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The plasma levels and the β- blocking effect of metoprolol and its active metabolite α- hydroxymetoprolol have been studied after i.v. bolus injections of the substances to dogs. For both substances the β- blockade increased with the dose, and there was a linear relationship between percent reduction in exercise heart rate and the logarithm of plasma concentration. The dose of the metabolite, however, had to be 5 times higher than that of metoprolol to induce the same degree of β- blockade. Because of differences in the volume of distribution, 2.0 liters/kg for α- OH-metoprolol and 3.5 liters/kg for metoprolol, the 5 times higher dose of α- OH-metoprolol resulted in 10 times higher plasma levels of the metabolite than of metoprolol. α- OH-Metoprolol was more slowly eliminated (t1/2∼7.0 hr, total body clearance ∼3.5 ml-kg−1-min−1) than metoprolol (t1/2∼2.0 hr, total body clearance ∼20.0 ml-kg−1-min−1). Approximately 5% of an i.v. dose of metoprolol was metabolized to α- OH-metoprolol. The half-life of the endogenously formed metabolite was the same as after an i.v. dose of the compound.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01062389
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  • 51
    Digitale Medien
    Digitale Medien
    Studies on fish scale formation and resorption. I. Fine structure and calcification of the scales in Fundulus heteroclitus (Atheriniformes: Cyprinodontidae)Contribution No. 220, Belle W. Baruch Institute of Marine Biology and Coastal Research, University of South Carolina, Columbia, South Carolina 29208. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 49-65 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Fine structure of the scales of Fundulus heteroclitus was examined by scanning and transmission electron microscopy. The concentric ridges of the scale surface were characterized by the presence of minute, highly calcified, denticles or tooth-like processes. Needle-shaped crystals of hydrox-yapatite were precipitated not only in the osseous layer but in the intimate lamellae of the fibrillary plate except in portions just below the grooves. The calcification of the osseous layer was observed to proceed by filling the matrix with patches of crystals. The fibrillary plate appeared to calcify by invasion of crystals from the upper calcified zone into spaces between collagen fibers.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590105
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  • 52
    Digitale Medien
    Digitale Medien
    Ultrastructural features of the retina and optic nerve of Strombus luhuanus, a marine gastropod (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 89-115 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The retina and optic nerve of Strombus luhuanus were examined by transmission electron microscopy in order to provide an ultrastructural basis for their electrophysiological responses, described elsewhere. The retina exhibits a distinct rhabdomeric layer and layers of cell nuclei and neuropile. These layers are comprised predominantly of three cell types that can be readily distinguished on the basis of their shape, their nuclei and cytoplasmic inclusions such as vesicles and filaments. One type of cell, apparently a photoreceptor that depolarizes in response to photic stimulation, possesses a long distal segment with microvilli; such distal segments comprise the bulk of the rhabdomeric layer. A second cell type, which appears to be supportive in function, contains a bundle of tightly packed tonofilaments that extend across the retina from the capsule to the vitreous body; this cell is quite narrow except in the region near the rhabdomeric layer, where it is expanded and wraps around the other cell types. A third type of cell possesses many short microvilli that project from its apical end into the rhabdomeric layer; it may be a second type of photoreceptor or another type of neuron. The retina also contains bundles of cilia that appear to project from a possible fourth type of cell. The layer of neuropile contains numerous processes that exhibit a variety of vesicle types and structures generally associated with synapses; these appear to play a role in mediating inhibitory and excitatory interactions between the retinal neurons. The optic nerve exhibits two populations of fiber distinguishable on the basis of mean diameter. Fibers in these two populations apparently yield “on” and “off” discharges in response to photic stimulation of the eye.
    Zusätzliches Material: 29 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590108
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  • 53
    Digitale Medien
    Digitale Medien
    Mandibular function in Galago crassicaudatus and Macaca fascicularis: An in vivo approach to Stress Analysis of the mandibleThis investigation was supported by the following: NIH Research Career Development Award (DE 00027), NIH Research Grant (DE 4531) and a NSF Research Grant (BNS 76-11924). (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 253-296 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Single-element and/or rosette strain gages were bonded to mandibular cortical bone in Galago crassicaudatus and Macaca fascicularis. Five galago and eleven macaque bone strain experiments were performed and analyzed. In vivo bone strain was recorded from the lateral surface of the mandibular corpus below the postcanine tooth row during transducer biting and during mastication and ingestion of food objects.In macaques and galagos, the mandibular corpus on the balancing side is primarily bent in the sagittal plane during mastication and is both twisted about its long axis and bent in the sagittal plane during transducer biting. On the working side, it is primarily twisted about its long axis and directly sheared perpendicular to its long axis, and portions of it are bent in the sagittal plane during mastication and molar transducer biting. In macaques, the mandibular corpus on each side is primarily bent in the sagittal plane and twisted during incisal transducer biting and ingestion of food objects, and it is transversely bent and slightly twisted during jaw opening. Since galagos usually refused to bite the transducer or food objects with their incisors, an adequate characterization of mandibular stress patterns during these behaviors was not possible. In galagos the mandibular corpus experiences very little transverse bending stress during jaw opening, perhaps in part due to its unfused mandibular symphysis.Marked differences in the patterns of mandibular bone strain were present between galagos and macaques during the masticatory power stroke and during transducer biting. Galagos consistently had much more strain on the working side of the mandibular corpus than on the balancing side. These experiments support the hypothesis that galagos, in contrast to macaques, employ a larger amount of working-side muscle force relative to the balancing-side muscle force during unilateral biting and mastication, and that the fused mandibular symphysis is an adaption to use a maximal amount of balancing-side muscle force during unilateral biting and mastication.These experiments also demonstrate the effects that rosette position, bite force magnitudes, and types of food eaten have on recorded mandibular strain patterns.
    Zusätzliches Material: 27 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590208
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  • 54
    Digitale Medien
    Digitale Medien
    Ultrastructure of the accessory glands of the Mediterranean flour mothAnagasta kuehniella (Zeller) (Lepidoptera: Pyralidae).Supported in part by U.S. Energy Research and Development Administration Contract P7603214. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 355-391 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Five regions are recognized in the accessory glands of the Mediterranean flour moth, Anagasta kuehniella (Zeller), on the basis of cellular morphology and aggregates of secretory material in the lumen. Some variation is found in each of the posterior four regions, especially the third one. In the most anterior region (region 1) the epithelium is composed of a single type of cell, while in each of the other regions there are two classes of cells. The cells of region 1 and one class in each of the other four regions are fairly typical exocrine cells with extensive rough endoplasmic reticula. Secretion is primarily via Golgi-derived vesicles. Apocrine secretion in the form of sloughing off of the apical cytoplasm probably also occurs in all regions but is most prominent in the posterior two regions. One class of cells is very similar in morphology in each of the posterior four regions though their secretory products form characteristic aggregates in the lumen. The second class of cells (foliate cells) occurring in the posterior four segments is most notably characterized by elongate apical projections that extend out into the lumen. The apical projections contain large quantities of glycogen, some microtubules, and, in some cases, many minute mitochondria. The membrane content of the projections is also very high. In the anterior regions, the membranes are mostly fused in pairs and typically form multilayered whorls. Fusion and whorl formation decrease in the posterior regions. The cytoplasm of the foliate cells has a high organelle content including many lysosomes and mitochondria. The latter exhibit considerable polymorphism, with particular forms occurring in the different regions of the glands. The apical projections of the foliate cells are detached during copulation, presumably as the result of nervous stimulation, and become a part of the ejaculate. Replenishment of all secretory material, including the apical projections, occurs after copulation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590306
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  • 55
    Digitale Medien
    Digitale Medien
    Partial regeneration of the above-elbow amputated rat forelimb. II. Electrical and mechanical facilitationSupported by the Veterans Administration Medical Research Program Project Number 7004-04 and a Medical Investigatorship Award to P.P. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 439-451 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This investigation was undertaken to examine the observations of Becker ('72) pertaining to the electrical facilitation of partial limb regenerative responses by means of Ag-Pt wire couples applied to the limb stumps of young, forelimb-amputated white rats. Additionally, in order to examine the possible role of mechanical effects of such device implantations, we have employed uncoupled devices delivering no current or potential difference. In the present experiments, in response to coupled device implantation, cartilage and bone were actively formed in the vicinity of the Pt electrode tip. These tissues contributed to the lengthwise extension of the limb and to the partial restoration of the distal humeral extremity. In limbs bearing the uncoupled electrical devices, qualitatively similar responses were noted, but osteogenesis was diminished in extent compared to that seen in limbs bearing the active or coupled devices. It is therefore necessary to consider the role of mechanical factors in the elicitation of the observed regenerative responses. Myogenesis was enhanced in electrically stimulated limbs, but not in those rats bearing uncoupled devices.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590309
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  • 56
    Digitale Medien
    Digitale Medien
    Avian scale development. VI. Ultrastructure of the keratinizing cells of reticulate scales (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 111-121 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Reticulate scales develop as radial symmetrical anlagen, in contrast to scuttate scales which appear initially as “epidermal placodes.” Unlike scuttate scales whose outer and inner epidermal surfaces elaborate β-and α-type keratins, respectively, reticulate scales elaborate only one type of epidermal surface which has been reported to give an α-type, X-ray diffraction pattern. We find that, histologically and ultrastructurally, this surface differs from either epidermal surface of scuttate scales. The keratinizing cells become filled with long interweaving bundles of α-filaments which aggregate into rather homogeneous α-fibrils. Keratohyalin granules, which have been shown to be associated with other keratinizing regions in the bird, do not form during the keratinization of reticulate scale epidermis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610107
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  • 57
    Digitale Medien
    Digitale Medien
    Ultrastructure of the parathyroid gland of the japanese lizard in the spring and summer season (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 145-155 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The ultrastructure of the parathyroid glands of adult Japanese lizards (Takydromus tachydromoides) in the spring and summer season was examined. The parenchyma of the gland consists of chief cells arranged in cords or solid masses. Many chief cells contain numerous free ribosomes and mitochondria, well-developed Golgi complexes, a few lysosome-like bodies, some multivesicular bodies and relatively numerous lipid droplets. The endoplasmic reticulum is mainly smooth-surfaced. Cisternae of the rough endoplasmic reticulum are distributed randomly in the cytoplasm. Small coated vesicles of 700-800 Å in diameter are found occasionally in the cytoplasm, especially in the Golgi region. The chief cells contain occasional secretory granules of 150-300 nm in diameter that are distributed randomly in the cytoplasm and lie close to the plasma membrane. Electron dense material similar to the contents of the secretory granules is observed in the enlarged intercellular space. These findings suggest that the secretory granules may be discharged into the intercellular space by an eruptocrine type of secretion. Coated vesicles (invaginations) connected to the plasma membrane and smooth vesicles arranged in a row near the plasma membrane are observed. It is suggested that such coated vesicles may take up extracellular proteins. The accumulation of microfilaments is sometimes recognized. Morphological evidence of synthetic and secretory activities in the chief cells suggests active parathyroid function in the Japanese lizard during the spring and summer season.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610203
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  • 58
    Digitale Medien
    Digitale Medien
    Intrinsic organization of snake dorsomedial cortex: An electron microscopic and golgi study (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 185-210 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The cellular populations present in dorsomedial cortex in the snakes Constrictor constrictor, Natrix sipendon and Thamnophis sirtalis are described at the light microscopic level using Nissl and Golgi preparations as well as at the ultrastructural level. This area plays a central role in cortical organization in snakes by participating in major commissural and association projections.Systematic analyses of Golgi preparations indicate that five populations of neurons are present in dorsomedial area and have a preferential laminar distribution. Layer 1 stellate cells have somata positioned in the center of the outermost cortical layer, layer 1. Their dendrites are confined to this layer. Double pyramidal cells have their somata loosely packed in layer 2. Their dendrites bear a moderate population of spines, ascending through layer 1 to the pial surface and descending partially through layer 3. Some double pyramidal cells have somata displaced downwards into the upper third of layer 3. These neurons closely resemble the layer 2 double pryamidal cells. Layer 3 stellate cells have somata positioned in the middle third of layer 3. Their dendrites extend in all directions throughout layer 3 and through layer 2 into layer 1. Finally, horizontal cells have their somata positioned deep in layer 3, near the ventricle, and dendrites aligned concentric with the ventricle.Comparison of the organization of the known afferents to dorsomedial area with the distribution of the five cell types suggests that the laminations of both afferent fibers and dorsomedial neurons places specific neuronal populations in synaptic contact with specific sets of afferents.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610207
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  • 59
    Digitale Medien
    Digitale Medien
    The extensor assembly in two species of opossum, Philander opossum and Didelphis marsupialis (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 337-345 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In considering primate and hominoid phylogeny, the fundamental position assigned to opossums is explained partially by the characteristic morphology of their hands and feet. One of the main functional features of the human hand is the ability to make a stabilized arch of the finger. Because the extensor assembly plays a key role in establishing an arched finger, the extensor systems of the digits of both the hands and feet were studied in two species of opossum, Philander opossum and Didelphis marsupialis.In the foot, two extensor tendons join in each toe to form one tendinous plate, which inserts onto the base of the second phalanx. Lumbricals join this plate along the tibial side, and interosseus insertions are found, although a true interosseus wing is lacking. At the proximal interphalangeal level, a terminal tendon takes its origin from this tendinous plate. This terminal tendon is oval in cross-section and contains elastic structures. Oblique bands arise from this terminal tendon and run proximally along the proximal interphalangeal joint inserting onto the base of the first phalanx. There are elastic structures in the flexor tendon on the dorsal side near its site of insertion.In the hand, the main extensor tendons are arranged differently and the interossei contribute substantially to the extensor assembly. Otherwise, the extensor assembly of the hands and feet are quite similar. The function of the so-called paratendinous intravaginal flexors is discussed as are evolutionary aspects of the extensor assembly.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610307
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  • 60
    Digitale Medien
    Digitale Medien
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620201
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  • 61
    Digitale Medien
    Digitale Medien
    Comprehensive schemata on the histology of the liver with consequences in terminology (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 211-219 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: New schemata of the liver are presented to discuss the combination of the three kinds of liver lobules known until today in a chalk-talk-manner. Terminology is also discussed. Further investigations are needed involving the construction and the vascular pattern of compound lobules of the three individial lobules of the liver in different species.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620204
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  • 62
    Digitale Medien
    Digitale Medien
    A comparative study of the differentiation and involution of the mullerian duct and wolffian duct in the male and female fetal mouse (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 175-209 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The present investigation has examined the ultrastructural differentiation of the genital ducts of both sexes of fetal mice. The emphasis of observations was placed on the phenomenon of morphogenetic cytolysis, particularly during the critical periods of Wolffian duct stabilization and Mullerian duct involution.Both developing and regressing genital ducts evidence extensive cytolysis. Autophagy appears to be the mechanism of morphogenetic change in the developing male Wolffian duct. Autophagy, heterophagy, and degeneration in situ are all prominent cytolytic activities in female Wolffian duct involution. The developing female Mullerian duct undergoes extensive morphogenetic remodeling by the mechanisms of autophagy, heterophagy, and degeneration in situ. In the male Mullerian duct, autophagy, heterophagy, and degeneration in situ are also prominent. In addition, whole degenerated epithelial cells are extruded from the duct early in regression which may be related to the transformation of periductal mesenchymal cells into an “epithelioid cell cuff” which does not form around the regressing Wolffian duct. The formation of this mesenchymal condensation surrounding the duct is also accompanied by the protrusion of Mullerian epithelial cell cytoplasm into the mesenchymal cells. These observations may evidence a complex epithelial-mesenchymal interaction occurring during male Mullerian duct involution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620203
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  • 63
    Digitale Medien
    Digitale Medien
    Editorial (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 311-311 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620302
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  • 64
    Digitale Medien
    Digitale Medien
    Structure and carbohydrate histochemistry of the intestine in ten teleostean species (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 343-359 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The morphology and carbohydrate histochemistry of ten teleostean intestines are compared. Although there is an absence of regional differentiation seen in higher vertebrates, specializations in some species occur in the form of intestinal swellings, pyloric ceca and recta, the latter separated by a valve. The intestinal lumen is lined by a simple columnar epithelium interspersed with goblet cells; multicellular intestinal glands are absent. Thick basement membranes seen in centrarchids and Perca flavescens closely resemble the stratum compactum found in the lamina propria of esocids. Granular cells, which vary in number from species to species, are often seen in the mucosa and submucosa but less frequently in the muscularis. In species with intestino-rectal valves, a rectum is easily defined by the abrupt appearance of lower mucosal folds, more goblet cells and a thicker muscularis. In the remaining species the above features appear gradually in the distal intestine. Goblet cells show species variations in localization of epithelial mucosubstances, which in broad terms are recognized as sulfomucins, sialomucins and neutral mucosubstances. In both proximal and distal intestines the majority of goblet cells contain sialomucin although small amounts of sulfomucin are also often present. In species without intestino-rectal valves, no changes in carbohydrates occur between proximal and distal intestines. The possible significance of the heterogeneous character of digestive tract mucosubstances is discussed.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620305
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  • 65
    Digitale Medien
    Digitale Medien
    The morphology of the sex pheromone gland in Drosophila grimshawi (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 177-183 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The morphology of a sex pheromone-producing gland found in the abdomen of Drosophila grimshawi males was studied by light and electron microscopy. This gland, consisting of two intra-anal lobes, contains cells that resemble those of other insect pheromone glands. However, in contrast to many other insect pheromone glands that release pheromone through the cuticle, cells of the intra-anal lobes secrete into a canaliculi-duct system that empties into the anal region. The liquid secretory product flows along the surface of the intra-anal lobes and is brushed onto the substrate by fingerlike projections on the lobes' surfaces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610206
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  • 66
    Digitale Medien
    Digitale Medien
    Ultrastructure of the sacculus and lagena in a moray eel (Gymnothorax sp.) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 241-256 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The ultrastructure of the sacculus and lagena of a moray eel, Gymnothorax sp., was investigated using scanning and transmission electron microscopy. Particular emphasis was placed on the orientation of the sensory hair cells and on the ultrastructure of the sensory cells. The ciliary bundles on the sensory hair cells are of several types, each having a different size relationship between the kinocilium and stereocilia. The cell bodies of the sensory cells are similar to the mammalian type II sensory cell. There were no apparent differences in the cell bodies between sensory cells with different ciliary bundles.Hair cell orientation patterns on the saccular and lagenar maculae differ from patterns found in other fishes. The posterior side of the saccular macula in Gymnothorax has cells oriented dorsally and ventrally, as is typical in other non-ostariophysan species. The anterior end of the saccular macula has alternating groups of anteriorly and posteriorly oriented cells, a situation that differs from the more typical pattern in which anteriorly oriented cells are found on the ventral side of the macula while posteriorly oriented cells cover the dorsal side of the macula. The orientation of cells on the lagena includes ventral cells that are located above a group of dorsally oriented cells. In many other non-ostariophysans, ventrally oriented cells are generally posterior to the dorsally oriented cells.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610302
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  • 67
    Digitale Medien
    Digitale Medien
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620101
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  • 68
    Digitale Medien
    Digitale Medien
    The blood supply of muscle spindles in some mammals and the pigeon (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 323-335 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The blood supply of muscle spindles was studied in serial cross sections in macaque, cat, rabbit, guinea pig, mouse and pigeon muscles which had been incubated in a medium containing 3,3′ diaminobenzidine. Lumina of blood vessels were recognized by the reaction product that was localized within erythrocytes. The outer capsule was well vascularized, but few or no capillaries were seen in the periaxial space. The inner spindle capsule, which closely invests the axial bundle, was rarely contacted by periaxial capillaries at the equator and juxtequator. Capillaries occurred more frequently adjacent to intrafusal fibers at the polar region and beyond the end of the outer capsule. Shorter diffusion distances and, usually, higher capillary densities were found at the polar region than at the spindle midsection. This suggests that transcapillary exchange at the polar segment is nearer to conditions prevalent in extrafusal muscle than elsewhere in the spindle, provided the inner and outer capsules are not less permeable at the poles than at the midsection. Differences in blood supply among mammalian species appear to be related to receptor size.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610306
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  • 69
    Digitale Medien
    Digitale Medien
    Origin and fate of germ cells in male and female embryos of Haplothrips verbasci (Osborn) (Insecta, Thysanoptera, Phlaeothripidae) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 323-343 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Comparison of germ cells in male and female embryos of the arrhenotokous thrips, Haplothrips verbasci, yields the following observations: A mean of 11 cleavage energids enter the posterior pole plasm of the egg after the sixth cleavage division and apparently become pole cells when they take up polar granules in their cytoplasm. The cells proliferate asynchronously prior to and during anatrepsis to yield a mean of 36 germ cells in male embryos and 31 in females. Visible sexual differentiation of germ cells begins during germ band elongation and is completed shortly after the appearance of appendages. Female germ cells are larger than those of the males and may contain two nucleoli. The germ cells separate into two groups just before katatrepsis and mesodermal cells collect about these to form the primary epithelial sheaths of the gonads and the primordia of the gonoducts shortly after revolution is completed. Each gonad contains a mean of 13 germ cells in male embryos and 7 in females - a number that persists until mitosis resumes after hatching. During ketatrepsis, a mean of 11 germ cells in male embryos and 2.6 in females fail to be enclosed within the gonads, become dispersed in the yolk and perhaps transform into vitellophages.Germ cell development in H. verbasci embryos resembles similar events taking place in psocid embryos, providing additional evidence for a close phylogenetic relationship between Thysanoptera and Psocoptera.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051600305
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  • 70
    Digitale Medien
    Digitale Medien
    Presence and development of a sensory formation in the eyestalk of the crayfish, Astacus leptodactylus (Nordmann, 1842), during its embryonic, larval and adult lifeThis study was partially sponsored by C.N.R.S. (France) under grànt A.T.P. International 1976-2602. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 39-51 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A sensory papilla is described in the eyestalk of the crayfish Astacus leptodactylus during the last embryonic stages and during larval stages by light microscopy. This region was also investigated with the scanning electron microscopy, which showed sensory hairs in the postmolt adult; they disappear during intermolt and premolt. Simultaneous cyclic changes in hair papillae are observed in the hypodermis. The possibility of a chemoreceptive function is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610104
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  • 71
    Digitale Medien
    Digitale Medien
    Membrane production and yolk degradation in the early fly embryo (Calliphora erythrocephala meig.): An ultrastructural analysis (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 53-77 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Formation of nuclear envelopes during the last cleavage mitosis and the formation of the cell membranes during the cellularization of the blastoderm have been studied ultrastructurally in the blowfly egg. Dense bodies arising from yolk granules by budding could contain membrane material destined to be incorporated into the new membranes of the blastoderm. The presence of transitional structures indicates that these bodies can be converted into dark multivesicular bodies. Large amounts of endoplasmic reticulum are found around the mitotic nuclei. Clusters or branched chains of vesicles associated with this are interpreted as evidence for the formation of endoplasmic reticulum by the breakdown of dark multivesicular bodies. Nuclear envelopes of mitotic daughter nuclei probably originate from endoplasmic reticulum. The egg contains both intranuclear and extranuclear annulate lamellae.The main events of cytokinesis are furrow initiation and cell membrane growth during the slow first phase, but probably only cytokinetic movement during the rapid second phase. On the assumption that cell membrane growth occurs by incorporation of complete membrane pieces, the addition of coated vesicles and/or light multivesicular bodies is definitely most probable. Some intermediate profiles indicate that light and dark multivesicular bodies are related. The membrane needed for second phase cytokinesis could well be provided by the unfolding of surface microvilli and protuberances of the furrow canal.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610105
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  • 72
    Digitale Medien
    Digitale Medien
    Countercurrent blood vessel arrangement in beaver (Castor canadensis) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 169-175 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The vascular anatomy of five beavers (Castor canadensis) was studied by dissection and injection of arteries and veins with vinyl acetate. There is extensive countercurrent arrangement of arteries and veins distal to and including the common iliac artery and veins. Two types of countercurrent vessels occur (1) a venae comitantes type in which two or three veins surround a central artery, and (2) a modified rete type. The retia are located proximal to the large flat tail and the webbed hind feet. Two bypass veins are described for the feet and tail and the significance of these structures in temperature regulation is stressed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610205
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  • 73
    Digitale Medien
    Digitale Medien
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610301
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  • 74
    Digitale Medien
    Digitale Medien
    Ultrastructure of the type “B” cells in the rectal pad epithelium of Locusta migratoria (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 221-232 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The electron microscopical structure of the type “B” cells in the rectal pad epithelium of Locusta is described. The type “B” cells occur singly in the distal region of the rectal pad epithelium. They are characteristically goblet shaped and join with contiguous type “A” or rectal pad cells, near the apical surface by means of a restricted region of septate desmosomes. Type “B” cells possess a microvillate apical membrane, with the villi arranged as a rosette overlying the apical inaginations of adjacent type “A” cells.Large numbers of microtubules and vacuoles of various sizes containing an assortment of inclusions are present in the apical region of the type “B” cells. Many of the microtubules insert distally on hemidesmosomes located in the apical plasma membrane. Rough endoplasmic reticulum and mitochondria are also present but neither are abundant. The possible significance of these findings is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590205
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  • 75
    Digitale Medien
    Digitale Medien
    The development of amphids and amphidial glands in adult Syngamus trachea (Nematoda: Syngamidae) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 299-321 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Nematode amphids are a pair of lateral cephalic sense organs, each comprising a group of sensory endings terminating in a cuticle-lined pit. In Syngamus trachea, a parasite of birds, each amphid is surrounded by two non-nervous supporting elements, a large gland cell basally and a smaller supporting cell anteriorly. The amphidial glands display high levels of secretory activity from five to six days postinfection. Secretory material is discharged through the lumen of the sense organ onto host tissue. The ultrastructure of amphids and amphidial glands has been investigated in newly moulted, immature and mature adults to trace the development of glandular activity and its effect on amphid-amphidial gland relationships. In newly moulted adults, the glands have very low levels of secretory activity and appear to act only as supporting cells to the amphids. As secretory activity increases, the gland cell membrane surrounding the sensory endings is elaborated into a reticulum which probably forms the secretory surface. In mature adults the amphid pit is swollen and filled with secretion; the sensory endings are relegated to the periphery of the lumen. It is suggested that amphidial glands develop from typical supporting cells, but acquire a new role possibly associated with parasite attachment.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051600304
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  • 76
    Digitale Medien
    Digitale Medien
    Histochemical and ultrastructural features of the aorta of the slug (Limax maximus) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 1-21 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: As a part of a continuing study of unusual molluscan tissues, the “chondroid” tissue (Hyman, '67) associated with the anterior and posterior aortae of the slug (Limax maximus) was examined by light and electron microscopy. Unlike the odontophoral tissue of this species (Curtis and Cowden, '77), the “chondroid” tissue comprising the adventitial layer of the aorta consists of large, glycogen-filled cells with characteristic arrays of pores in their plasma membranes resembling those of the “globular” cells (Rogers, '69; Fernandez, '71); “fibrocytes” (Nicaise et al., '66; Baleydier et al., '69; Nicaise, '73); “Blasenzellen” or “Leydig” cells (Wondrak, '69; Stang-Voss, '70; Buchholz et al., '71; Stang-Voss and Staubesand, '71; Wolburg-Buchholz, '72); or “pore” cells (Sminia, '72; Beltz, '77) of other mollusks. The anterior and posterior aortae are very similar in organization, except that the anterior aorta is larger in diameter; its wall is thinner; and it lacks calcification. Both the anterior and posterior aortae possess a loosely organized (incomplete) endothelial layer surrounded by two layers of innervated smooth muscle. The smooth muscle cells possess fibrous surface specializations resembling hemidesmosomes as well as large numbers of tubular or rounded vesicles in association with their plasma membranes. Blood cells (amoebocytes) containing large glycogen deposits and distinctive membrane-enclosed cytoplasmic inclusions can be found occasionally in the walls of the vessels.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610102
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  • 77
    Digitale Medien
    Digitale Medien
    The hind limb musculature of the brown kiwi, Apteryx australis mantelli (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 33-73 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The most complete account of the hind leg muscles of the kiwi was published a century ago by Sir Richard Owen, in his seventy-fifth year. This extensively-cited work has several omissions and errors, and while certain of these were corrected by subsequent authors, sufficient uncertainty remains to warrant a reinvestigation. In the present study a detailed description of the hind leg musculature is given, based upon dissections of two frozen specimens. An indication of the possible function of each muscle is given by assessing its size, action, and fiber-arrangement, together with tentative data on the relative abundance of twitch and tonus fibers.The correlation between surface features of bones and muscle attachments is investigated with a view to interpreting palaeontological material. Although the limb and pelvic bones are marked by numerous features which suggest muscle attachments, relatively few can be positively identified with specific muscles. Only 23% of the muscle origins and insertions can be identified, and, with three possible exceptions, no indication of relative size is given by the scars. The possibility of being able to reconstruct the musculature of the kiwi from its skeletal anatomy, much less that of its extinct relatives, is remote.
    Zusätzliches Material: 26 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051600105
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  • 78
    Digitale Medien
    Digitale Medien
    A model to explain the posterior limit of the bite point in reptiles (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 165-168 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A biomechanical model of the jaw mechanism in some reptiles is presented. Symmetrical muscle activity that produces equal forces on both sides of the head is assumed. The model predicts the position of the most posterior bite point and offers a functional explanation for this prediction. Turtles are used to illustrate the idea.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051600204
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  • 79
    Digitale Medien
    Digitale Medien
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051600201
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  • 80
    Digitale Medien
    Digitale Medien
    Organization of nucleus rotundus, a tectofugal thalamic nucleus in turtles. I. Nissl and Golgi analyses (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 121-141 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This study consists of a detailed cytoarchitectonic and Golgi analysis of a major tectofugal thalamic nucleus in the red-eared turtle, Pseudemys scripta elegans. Neurons in nucleus rotundus have a unimodal soma size distribution and a common dendritic branching pattern. They have long dendrites which undergo sparse, dichotomous branchings and contribute to dendritic fields that cover a third to half the dimensions of the nucleus. Spicules, 1-2 μ long, and complex appendages, 5-20 μ long, are found with low density on many dendrites in Golgi-Kopsch material. A few cells have beaded dendritic processes. Three cytoarchitectural regions can be differentiated in nucleus rotundus: a shell, a cell-poor region and a core. The shell is a monolayer of somata forming the peripheral boundary of most of the nucleus. The cell-poor region forms a thin zone concentric with and internal to the shell. Shell cells send some of their dendrites concentrically within this zone and others radially into the core region. Core neurons are dispersed within the neuropil of the nucleus and usually have spherical dendritic fields. However, peripheral core neurons have asymmetrical fields, so their dendrites do not extend beyond the shell. Caudomedial and central subregions of the core can be defined on the basis of neuronal density and cytology. Somata in the caudomedial area of the core are densely packed and have slightly darker staining cytoplasm than those in the central subregion. However, their dendrites are similar to those of the central core neurons. There is extensive dendritic overlap between the two subregions.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051600202
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  • 81
    Digitale Medien
    Digitale Medien
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610101
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  • 82
    Digitale Medien
    Digitale Medien
    Glycogen metabolism in the prelaid chick embryo (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 23-38 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Glycogen metabolism has been studied during the development of the early chick embryo, at the cytochemical and ultrastructural levels. Two waves of glycogen synthesis and breakdown have been found. In the first, free clusters of glycogen particles are synthesized at late oogenesis. These clusters are found later in invaginations of the membrane of vesicles containing a floc-cular material (FLOV). The glycogen clusters are degraded there during ovulation and the first hours in the oviduct. The second wave of glycogen synthesis begins before cleavage, reaching a maximum at mid-uterine age. This second wave occurs in another type of vesicle (GLYV), which eventually disintegrates releasing free clusters of glycogen granules. This glycogen is degraded in membranous structures containing a floccular material, as in the first wave of degradation. The degradation ends at the late uterine stages, and at the same time numerous ribosomes are formed. This period corresponds to area pellucida formation, which probably depends on the energy liberated during the second wave of glycogen degradation.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610103
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  • 83
    Digitale Medien
    Digitale Medien
    Studies on the tardigrades. IV. Fine structure of the hindgut of Milnesium tardigradum doyère (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 79-109 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The hindgut of the semi-terrestrial tardigrade, Milnesium tardigradum was examined with light and electron microscopy. The hindgut consists of a cloaca and an anterior hindgut. It is delineated anteriorly by the pylorus into which four Malpighian tubules empty and posteriorly, by a broad cloacal slit. A single oviduct enters the hindgut at the junction between the cloaca and the anterior hindgut. Two pairs of muscles insert on the cloaca and anterior hindgut respectively. Electron microscopic observations demonstrate that the anterior hindgut is a specialized transporting epithelium. The luminal surface is covered by a thin layer of cuticle which penetrates into channel-like invaginations. Numerous mitochondria are concentrated apically. The basal and lateral surfaces are also folded. The cells are joined apically by deep tight junctions and a simple basal lamina lines the entire hindgut. The cloaca which receives the contents of the gut and Malpighian tubules as well as gametes of the reproductive tract is a transitional organ that exhibits several characteristics of the hypodermis and anterior hindgut. The cuticle of the cloaca changes sequentially from the complex structure of the integument to a simple layer of the anterior hindgut. The function of the hindgut is discussed with emphasis on the possible response of the anterior hindgut to a hypoosmotic habitat, evaporative water loss during the induction of anhydrobiosis and low oxygen tension.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610106
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  • 84
    Digitale Medien
    Digitale Medien
    The fine structure of blood follicles in the earthworm genera Amynthas and Lumbricus (Annelida: Oligochaeta) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 123-143 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Blood follicles of the earthworm Amynthas are hemoglobin-containing, sac-like dilatations of blood vessels which connect to the general circulation. Grape-like clusters of follicles are found posterior to the pharynx, among tufts of micronephridia, and single follicles are located among cells of the pharyngeal gland. In Lumbricus, follicles take the form of simple swellings and irregular-shaped diverticula of nephridial capillaries.The fundamental structure of the wall of follicles and of vessels in both genera is the same and consists of two layers: an extracellular vascular lamina and an outer (coelomic) covering of smooth muscle-like myoperithelial cells. Hemocytes may be free and circulating or they may facultatively attach to the vascular lamina as littoral cells, constituting an incomplete endothelium-like surface. Hemocytes that appear to be in the process of attaching or detaching are rounded, while adherent cells are flattened and elongate. Free and littoral hemocytes actively endocytose packets of circulating extracellular hemoglobin.Hemocytes within follicles possess radiating cell processes which also endocytose hemoglobin. Although these cells were presumed to secrete hemoglobin, staining with 3,3′-diaminobenzidine confirms the presence of hemoglobin only within pinosomes and not within protein-synthesizing or packaging organelles. The presence of hemosiderin-like bodies suggests that follicular hemocytes catabolize hemoglobin.Blood follicles apparently provide a means of significantly increasing cell-surface area for hemoglobin processing, without substantially increasing the volume and pumping load of the circulatory system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610202
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  • 85
    Digitale Medien
    Digitale Medien
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610201
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  • 86
    Digitale Medien
    Digitale Medien
    The mouthparts of female Corethrella brakeleyi and C. wirthi (Diptera: Chaoboridae) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 157-167 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The mouthparts of female Corethrella brakeleyi and C. wirthi were studied using light and electron microscopy. Mandibles, hypopharynx and labium are highly sclerotized and are modified for obtaining blood meals. All structures were larger in C. brakeleyi than in C. wirthi except mandibular and hypopharyngeal teeth; these were smaller and more numerous in C. brakeleyi. The labium of both species terminates in peg-like structures which are similar to those reported from several genera of mosquitoes. Sensillae on the second segment of the maxillary palps appear to be identical to those described in both biting and nonbiting male and female blackflies.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610204
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  • 87
    Digitale Medien
    Digitale Medien
    The structure of the canary's incubation patch (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 425-451 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The gross morphology, histology and ultrastructure of the canary's incubation patch and the ventral apterium from which it arises are described. The apterium is vascularized by pectoral, external mammary, incubation, and prepubic arteries. It is innervated by cutaneous branches of spinal nerves. It has a surface area of 6 cm2.Its epidermis is a stratified squamous epithelium with basal, intermediate, transitional and cornified layers. Cells in the stratum germinativum contain a normal array of organelles, but are characterized by tonofilaments, desmosomes and interdigitating surfaces. Cellular organelles disappear in the stratum transitivum and are replaced by large vacuoles and keratohyalin bands. Nonmyelinated nerve fibers are abundant in the stratum germinativum.The dermis consists of (1) an avascular layer of dense collagen subjacent to the epidermis and containing many nonmyelinated nerves, and (2) an underlying layer of areolar connective tissue containing blood vessels, lamellar corpuscles and nerves. A layer of coarse elastic fibers, reinforced by collagen and smooth muscle, separates the dermis from subcutaneous tissue.In contrast to the ventral apterium, the incubation patch is featherless and visibly hypervascular and edematous. Its epidermis is both hypertrophic and hyperplastic. Large spaces separate cells in the stratum germinativum. The visible hypervascularity is due to hyperemia and increased number and size of blood vessels in the dermis. Visible edema is due to the accumulation of fluid interstitially. Although no histological differences exist among various regions of the ventral apterium, such differences are present in the incubation patch.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620309
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  • 88
    Digitale Medien
    Digitale Medien
    Cell death and optic fiber penetration in the optic stalk of the chick (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 67-75 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The role of dying cells in the optic stalk in relation to retinal fiber migration was investigated in the chick embryo. Cell death was analysed at various stages of development by counting pycnotic nuclei and also by the Gomori acid phosphatase reaction, while nerve fibers were visualised by the Bodian method. A wave of cell death, beginning in the neural retina at stage 18 and advancing with time through the stalk towards the diencephalon, occurred simultaneously or slightly prior to differentiation and migration of ganglion cell axons. Cell death stopped and gliogenesis occurred in the stalk after penetration by retinal fibers. Cell death occurred in the stalk even when fiber penetration was prevented by optic cup ablation. In this case, necrosis ensued until almost complete degeneration of the stalk, usually within three days after the operation, and gliogenesis did not occur. As the stalk degenerated, its cells became heavily pigmented. These observations suggest that the onset of cell death in the optic stalk is determined prior to and independently of retinal fiber penetration. On the other hand, cessation of cell death and subsequent gliogenesis occur only in the presence of ingrowing optic fibers.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620105
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  • 89
    Digitale Medien
    Digitale Medien
    Ultrastructure of an exocrine dermal gland in the gills of the grass shrimp, Palaemonetes pugio: Occurrence of transitory ciliary axonemes associated with the sloughing and reformation of the ductule (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 281-307 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Exocrine dermal glands, comparable to the class 3 glandular units of insects, are found in the gills of the grass shrimp, Palaemonetes pugio. The dermal glands are composed of three cells: secretory cell, hillock cell and canal cell. Originating as a complex invagination of the apical cytoplasm of the granular secretory cell, a duct ascends through the hillock and canal cells to the cuticular surface. The duct is divisible into four regions: the secretory apparatus in the granular secretory cell, the locular complex, the hillock region within the hillock cell and the canal within the canal cell. A tubular ductule is contained within the latter two regions. As the ductule ascends to the cuticular surface, its constitution gradually changes from one of a fibrous material to one which possesses layers of epicuticle. During the proecdysial period, the ductule is extruded into the ecdysial space and this is followed by the secretion of a new ductule. Temporary ciliary structures, located near the secretory apparatus of the secretory cell, are associated with the extrusion and reformation of the ductule. Characterized only by a basal body and rootlets throughout most of the intermolt cycle, the ciliary organelles give rise to temporary axonemic processes which ascend through the ductule toward the ecdysial space at the onset of proecdysis. Subsequently, the old ductule is sloughed off and a new ductule is reformed around the ciliary axonemes. Following this reformation, the ciliary axonemes degenerate. The function of cytoplasmic processes, derived from the apical cytoplasm of the secretory cell, is also discussed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610304
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  • 90
    Digitale Medien
    Digitale Medien
    Ordered membrane particles in rhabdomeric microvilli of the housefly (Musca domestica L.) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 309-321 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Rhabdomeric microvilli of the housefly were freeze-fractured (FF) and thin sectioned (TS) for ultrastructural examination. Ordered files of closely packed membrane particles (82 Å wide, 250 Å long) were seen (FF) on the microvillar membrane (usually E face). The long axis of each particle was canted about 45° to that of the microvillus. Occasionally particles in this array appeared on the P face. It is hypothesized that ordered particles may represent either a photopigment precursor stock, a second photolabile pigment, or the newly discovered sensitizing, UV-absorbing, photostable visual pigment. In the underlying membrane leaflet (P face) were found spherical (85 Å diameter) unoriented particles in a concentration of about 6,000/μm2. The size, shape and density of these structures are compatible with those of rhodopsin particles. These particles also covered the basal area of each microvillus. The findings from TS material were difficult to correlate with those from FF replicas. At high magnification the former showed that the plasma membrane of the transected microvillus is composed of spherical, hollow subunits (averaging 43 Å diameter), sometimes fused to form double, 86 Å units. These substructures were closely packed and continuous around the microvillus. This beaded plasma membrane, in rare cases, was doubled around the microvillus. In other instances the plasma membranes were continuous between neighboring microvilli. The physiological implications of these ultrastructural features are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051610305
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  • 91
    Digitale Medien
    Digitale Medien
    Interactions between Tectal Radial Cells in the Red-Eared Turtle, Pseudemys scripta elegans: An Analysis of Tectal Modules (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 17-36 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The optic tectum is a major subdivision of the visual system in reptiles. Previous studies have characterized the laminar pattern, the neuronal populations, and the afferent and efferent connections of the optic tectum in a variety of reptiles. However, little is known about the interactions that occur between neurons within the tectum. This study describes two kinds of interactions that occur between one major class of neurons, the radial cells, in the optic tectum of Pseudemys using Nissl, Golgi and electron microscopic preparations.Radial cells have somata which bear long, radially oriented apical dendrites from their upper poles and short, basal dendrites from their lower poles. They are divided into two populations on the basis of the distribution of their somata in the tectum. Deep radial cells have somata densely packed in the stratum griseum periventriculare. Their plasma membranes form casual appositions. Middle radial cells have somata scattered throughout the stratum griseum centrale and stratum fibrosum et griseum superficiale and do not contact each other. The apical dendrites of both populations of radial cells participate in vertically oriented, dendritic bundles. The plasma membranes of the dendrites in these bundles form casual appositions in the deeper tectal layers and chemical, dendrodenritic synapses within the stratum fibrosum et griseum superficiale. The synapses have clear, round synaptic vesicles and slightly asymmetric membrane densities. Thus, radial cells interact via both casual appositions and chemical synapses.These interactions suggest that radial cells may form a basic framework in the tectum. Because both populations of radial cells extend into the stratum fibrosum et griseum superficiale and stratum opticum, they may receive input from some of the same tectal afferent systems. Because the deep radial cells alone have somata and dendrites in the deep tectal layers, they may receive additional inputs that the middle radial cells do not. Neurons in the two populations interact via chemical dendrodendritic synapses, thereby forming vertically oriented modules in the tectum.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620103
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  • 92
    Digitale Medien
    Digitale Medien
    The telotrophic-meroistic ovary of megaloptera. I. The ontogenetic development (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 37-65 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Sialis flavilatera L. (Sialidae, Megaloptera) has telotrophic-meroistic ovarioles. The germ cells of the tropharium are organized into two distinct tissues, the central syncytium and the germ cell tapetum. The central syncytium consists of nurse cell nuclei embedded in a common cytoplasm which is rich in ribosomes and mitochondria. Cell membranes are totally absent. The germ cell tapetum surrounds the syncytium and consists of a monolayer of cells, each of which is connected with the central syncytium by an intercellular bridge. The oocytes differentiate from basal tapetum cells by previtellogenic growth. Their nutritive cords remain connected to the central syncytium by the intercellular bridge.Ovariole development starts soon after hatching with the immigration of germ cells into the ovariole-anlagen and is finished during pupal stages 23 months later. In apical regions of each tropharium, mitoses occur throughout larval life. The descendants enter the prophase of meiosis which lasts until pre-vitellogenesis; thus, a differential gradient of position and time is established. About 12 months after hatching, the central syncytium arises at the base of the tropharium from a membrane labyrinth in which intercellular bridges are entangled. Evidence is presented that endopolyploidization does not occur during germ cell differentiation.Finally, the results are compared with those found in Hemiptera and polyphage Coleoptera. The great diversities are interpreted as an indication for a polyphyletic origin of the telotrophic ovary.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620104
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  • 93
    Digitale Medien
    Digitale Medien
    Sense organs on the antennal flagellum of the mimosa webworm, Homadaula anisocentra (Lepidoptera, Glyphipterygidae) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 163-173 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Five different types of sense organs were found on the antennal flagellum of Homadaula anisocentra. These were (1) tactile hairs; (2) thick-walled chemoreceptors; (3) thin-walled chemoreceptors of several kinds; (4) styloconic chemoreceptors and (5) small chemoreceptor pegs in shallow depressions. No coeloconic sense organs were seen.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620202
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  • 94
    Digitale Medien
    Digitale Medien
    Growth and differentiation of secondary malpighian tubules in the cockroach, Periplaneta americanaThis work was submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biology at Northwestern University and was supported in part by the National Institutes of Health under Research Grants AM 14993, AM 14993, AM 19189, and FR 7028 to James L. Oschman and Betty J. Wall.An abstract of this work was published in J. Cell. Biol., 75: 32a, 1977. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 389-411 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Four differentiated Malpighian tubules (primary tubules) extend from the junction of the midgut and hindgut in newly hatched Periplaneta americana. Secondary tubules begin to develop near the base of the primary tubules before hatching and successive nymphal molts. The newly initiated tubules undergo cell division and extensive elongation through the middle of the following intermolt period. During this time, the cells of the distal, middle, and lower middle tubule regions are surrounded by a cellular sheath, have few cytoplasmic processes extending along their basal surfaces, have a small or nonexistent lumen, and contain extremely dilated cisternae of endoplasmic reticulum. The cellular sheath differentiates into the muscle which coils around the mature tubule. Tubules which begin development toward the end of one intermolt period begin to undergo cytodifferentiation toward the end of the next intermolt period. By the middle of an additional intermolt period, the basal infoldings and microvilli of cells in the distal, middle, and lower middle regions have the conformations typical for those regions in differentiated tubules; granular concretions and stellate cells are present within the middle region of the tubule.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051620307
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  • 95
    Digitale Medien
    Digitale Medien
    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590101
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  • 96
    Digitale Medien
    Digitale Medien
    The structure and distribution of external sense organs in newly hatched and mature earthworms (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 1-15 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Fully mature adult Eisenia foetida sensory buds are abundant on the prostomium and the first segment. In subsequent segments they are restricted to the anterior half where they form a single row aligned with the setae and encircling the worm. In the more posterior regions of the worm the buds are widely separated and fewer. The surface of each bud is a raised circular or oval area from which 15 to 100 so-called sensory hairs arise, being cylindrical and apparently flexible. The number of these projections decreases toward the posterior end of the worm.In worms newly emerged from egg cocoons, the general pattern of distribution and external form of sensory buds resembles that of adults, but the buds are much fewer and smaller than in adults. Although these worms emerge with their definitive adult number of segments, new buds and additional sensory projections are formed during post hatching development.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590102
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  • 97
    Digitale Medien
    Digitale Medien
    Morphology and distribution of Type II supraependymal cells in the third ventricle of the guinea pigSupported in part by NIH Grant RR-05387-13. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 67-79 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The distribution and morphology of phagocytic (Type II) supraependymal cells residing within the third ventricle of the guinea pig were investigated by scanning electron microscopy. Type II supraependymal cells were restricted to nonciliated regions of the ventricle. They were most numerous on the choroid plexus, abundant within the infundibular recess and were present on the ventricular floor in the region of the median eminence. Morphologically, they were characterized by a soma from which pseudopodia-like processes extended to the subjacent ependyma. Type II cells varied in configuration according to their location. Those residing on the choroid plexus typically had irregular somas and possessed processes that generally terminated in finger-like extensions. In contrast, cells on the ventricular floor and within the infundibular recess were stellate and possessed processes that terminated in fan-like cytoplasmic expansions. There were no differences noted in the frequency, distribution or morphology of Type II supraependymal cells in male and female animals. Furthermore, cell frequency did not appear to vary in relation to the estrous cycle. The data suggest that the pleomorphism exhibited by Type II supraependymal cells may reflect adaptations to diverse environmental conditions present within different regions of the third ventricle.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590106
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  • 98
    Digitale Medien
    Digitale Medien
    The intranuclear helices of Euplotes: Their substructure, localization, and apparent migration to the cytoplasm (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 81-87 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Study of the fine structure of the macronucleus in Euplotes eurystomus, a ciliate protozoon, during various stages of the cell division cycle has yielded new information about intranuclear helices. They are frequently observed at the periphery of chromatin bodies or next to the nuclear envelope, and they appear to be a constituent of nucleoli. The fibril that forms a helix is about 11-15 nm thick, and torus profiles of helices cut in cross section are about 35 nm in diameter. In substructure the helix is composed of a thin strand 3-5 nm thick which is coiled to form the 11-15 nm fibril; so the helix is a super-coiled structure. The intranuclear helices are present in the macronucleus throughout the cell cycle. They do not show obvious changes of relative abundance nor changes of relative localization in the nucleus, with one exception: they were never observed in the diffuse zone of replication bands. Evidence is presented indicating that nuclear helices migrate to the cytoplasm through nuclear pores. Although the chemical composition of the Euplotes intranuclear helices is unknown, information in the literature on similar helices in Amoeba indicates that they contain RNA and not DNA. The observations on Euplotes helices are consistent with a concept of “packaged” RNA for transport to the cytoplasm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590107
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  • 99
    Digitale Medien
    Digitale Medien
    Structure of the shell and tertiary membranes of eggs of softshell turtles (Trionyx spiniferus) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 131-143 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Eggs of the turtle Trionyx spiniferus are rigid, calcareous spheres averaging 2.5 cm in diameter. The eggshell is morphologically very similar to avian eggshells. The outer crystalline layer is composed of roughly columnar aggregates, or shell units, of calcium carbonate in the aragonite form. Each shell unit tapers to a somewhat conical tip at its base. Interior to the crystalline layer are two tertiary egg membranes: the outer shell membrane and the inner shell membrane. The outer shell membrane is firmly attached to the inner surface of the shell, and the two membranes are in contact except at the air cell, where the inner shell membrane separates from the outer shell membrane. Both membranes are multi-layered, with the inner shell membrane exhibiting a more fibrous structure than the outer shell membrane. Numerous pores are found in the eggshell, and these generally occur at the intersection of four or more shell units.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590110
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  • 100
    Digitale Medien
    Digitale Medien
    Afferent and efferent components of the facial nerve in the bullfrog (Rana catesbeiana)This work was supported by grants from the National Aeronautics and Sapace Administration: NAS 9-15213 and NSG 7441. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 245-252 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The afferent and efferent components of the facial nerve were traced within the brain stem of Rana catesbeiana, using three different neuroanatomical techniques. Primary afferent fibers could be traced to the spinal tract of trigeminal nerve and to fasciculus solitarius as far caudally as the first or second spinal segment, using silver degeneration methods. Cobalt filling of the entire nerve showed the same distribution of afferent fibers, as well as the filling of the cells within the mesencephalic nucleus of trigeminal, indicating the origin of a proprioceptive component of the facial nerve. Cobalt iontophoresis and horseradish peroxidase experiments showed that the motor nucleus of the facial nerve was located just ventral to the fourth ventricle, and caudal to the motor nucleus of trigeminal. The distribution of afferent fibers to fasciculus solitarius and the spinal tract of trigeminal is similar in some respects to the distribution of afferent fibers from the trigeminal and vagal nerves in the bullfrog. The afferent fibers from the three cranial nerves are found as far caudally in the brain stem as the second spinal segment.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051590207
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