ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • pharmacokinetics  (33)
  • Scanning electron microscopy  (17)
  • Springer  (50)
  • American Institute of Physics (AIP)
  • Cambridge University Press
  • 2020-2023
  • 1975-1979  (50)
  • 1935-1939
  • 1977  (50)
Collection
Keywords
Publisher
  • Springer  (50)
  • American Institute of Physics (AIP)
  • Cambridge University Press
Years
  • 2020-2023
  • 1975-1979  (50)
  • 1935-1939
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 181 (1977), S. 31-40 
    ISSN: 1432-041X
    Keywords: Cell migration ; Mesoderm ; Gastrulation ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary At the end of gastrulation, the lateral mesoderm of amphibian embryos migrates ventrally between the ectoderm and the endoderm. The present study is an examination of the morphology of the leading cells of the mesodermal sheet and of the substratum over which they move (the inner surface of the ectoderm). The cells of the leading edge of the mesoderm are generally round, with very short and narrow flattened projections in the forward direction. These projections do not have a “ruffled” morphology, regardless of whether fixation is carried out before or after the ectoderm and mesoderm are dissected away from the endoderm. The inner surface of the ectoderm is covered with fine (450–500A) filamentous extracellular material and the ectoderm cells sometimes extend cytoplasmic processes (approx. 0.1 μ wide) onto the leading surface of the mesoderm or onto adjacent ectoderm cells. These studies indicate that the morphology of cell migration in amphibians is closer to that seen inFundulus than to that characteristic of chick or mammalian cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 137-145 
    ISSN: 1432-1041
    Keywords: Chlormethiazole ; pharmacokinetics ; metabolites ; oral administration ; young and elderly human subjects ; quantitative gas chromatographymass spectrometry ; whole blood distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma concentration of chlormethiazole and two of its metabolites has been measured in three young and three aged human subjects following administration of a single oral dose of chlormethiazole. A sensitive analytical method based on gas chromatography-mass spectrometry using the selective ion monitoring mode of operation was developed to permit quantitation of the plasma levels. The time course of the plasma concentration of chlormethiazole and metabolites showed wide inter-subject variation, particularly between the young and elderly subjects. Absorption of chlormethiazole was rapid in the subjects of both groups as assessed by the time taken to reach the peak plasma concentration. The mean peak plasma level of chlormethiazole was more than five times greater in the elderly (2.90±1.56 µg/ml) than in the young (0.55±0.58 µg/ml) subjects. The plasma level of chlormethiazole was consistently higher in the aged subjects and this was reflected by the larger area under the plasma curve in aged (7.62±5.37 µg.h/ml) than in young (0.94±0.66 µg.h/ml) individuals. Decreased pre-systemic elimination by the liver has been suggested as an important factor contributing to the higher plasma level in the elderly. Estimates of absolute systemic availability, calculated by reference to previous intravenous studies, were greater for the elderly subjects. The distribution of chlormethiazole in whole blood from six young and six elderly human subjects was investigated in vitro. The unbound fraction of chlormethiazole in plasma increased significantly from 0.308±0.035 in young subjects to 0.403±0.067 in the elderly. Distribution of the drug in whole blood was different for the two age groups; the fraction of drug distributed to plasma water was significantly greater and the fraction in blood cells was significantly less in the aged.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 171-174 
    ISSN: 1432-1041
    Keywords: Tolamolol ; hypertension ; pharmacokinetics ; mean steady-state concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Tolamolol was administered in a “double-blind” study to fifteen hypertensive patients by dose-titration against arterial blood pressure. Mean steady-state plasma tolamolol concentrations (Css) were determined for each patient from the area under the plasma concentration — time curve during a dosage interval whilst patients were receiving optimal tolamolol doses. No significant correlation was observed between daily tolamolol dose and Css; the relationship between fall in lying mean arterial pressure and Css also failed to reach conventional levels of statistical significance, but Css was observed to be correlated with the fall in standing pressure. The results suggest that plasma concentrations in excess of 200 ng/ml may be required to achieve an effective hypotensive response with the drug.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-1041
    Keywords: Muzolimine ; pharmacodynamics ; pharmacokinetics ; furosemide ; saluresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a biometrically planned, double-blind study on 12 Oedema-free male patients the saluretic effect of muzolimine 30 mg was compared with furosemide 40 mg. The plasma level of muzolimine was determined and correlated with its pharmacodynamics. In terms of excretion during the 12-hour observation period muzolimine 30 mg had as great a cumulative effect as furosemide 40 mg. There was a significant difference in the time-response curve. During the first two hours furosemide 40 mg had more saluretic effect than muzolimine 30 mg. Between two and four hours there was no significant difference between the two substances. Between four and six hours, however, muzolimine was somewhat more effective than furosemide, although the difference did not reach the level of significance. After 6 h there was no longer any difference between the two compounds. The half-life of the fall in concentration of muzolimine in plasma was 3.7 up to 10 h after its administration. The time-response curve of the increased urine excretion correlated well with the time course of the concentration of muzolimine in plasma.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 125-132 
    ISSN: 1432-1041
    Keywords: Valproic acid ; pharmacokinetics ; saliva concentration ; urinary excretion ; serum protein binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of valproic acid (VPA) have been studied in 6 healthy subjects following a single 600 mg dose, and after multiple doses over 12 days (1200 mg daily) of enteric-coated sodium valproate. A time lag before absorption of 1 to 2 h was observed in each subject, and then absorption was rapid, peak concentrations being recorded 3 to 4 h after administration of the dose. The plasma level decline was biphasic with a terminal half-life of 15.9±2.6 h in the single dose and 17.3±3.0 h in the multiple dose experiments. There was no evidence of dose dependent kinetics or autoinduction. Total plasma clearance was 0.0064±0.0011 l/kg×h. The apparent volume of distribution was small at 0.15±0.2 l/kg. The mean steady state plasma concentration (Css) reached after 4 days was 81.3±13.0 µg/ml. Css observed was lower than Css predicted (99.2±14.7 µg/ml) from single dose kinetics (p〈0.001). The difference was probably due to a reduction in plasma protein binding at higher concentrations. VPA concentration in saliva was between 0.4 and 4.5% of the total plasma concentration and was not equal to the concentration of unbound drug in plasma (6.7±0.8% unbound). 3.2% of the dose was excreted in urine as the parent drug and 21.2% as conjugated metabolites.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 367-373 
    ISSN: 1432-1041
    Keywords: Sulphamethizole ; tetracycline ; doxycycline ; rest ; exercise ; pharmacokinetics ; excretion ; absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The serum level and urinary excretion of sulphamethizole, tetracycline and doxycycline were studied in healthy volunteers subjected to intensive exercise and bed rest in a cross-over trial. Each group consisted of 7–8 subjects. The exercise or bed rest began 15 min before oral administration of the drug and was continued for the following 4 hours. During exercise serum drug concentration and the area under the serum concentration-time curve for each agent was significantly higher (p〈0.05) than the corresponding values at rest. Exercise greatly suppressed the renal excretion of tetracycline and doxycycline, but the decrease alone appeared insufficient to account for the pronounced increase in serum drug concentration. Total drug excretion in urine was unchanged. Thus, it seemed most unlikely that overall absorption from the gastrointestinal tract had been altered by exercise. However, the rate of absorption appeared to be more rapid in the exercise than in the rest period. Marked haemoconcentration was not produced by the exercise. In addition to changes in absorption and elimination rates, alteration in the volume of distribution might contribute to the higher serum drug concentration during exercise. Therefore, the level of physical activity should be considered in the interpretation of pharmacokinetic data both in clinical practice and in pharmacokinetic studies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 149-154 
    ISSN: 1432-1041
    Keywords: Hydroflumethiazide ; spectrofluorometry ; pharmacokinetics ; plasma half life ; renal excretion ; renal disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A spectrofluorometric method for determination of hydroflumethiazide in human plasma and urine has been developed. The limit of detection was 10 ng/ml plasma and 100 ng/ml urine. The plasma concentration of hydroflumethiazide was determined for 9–11 hours and excretion in urine for 24–37 hrs after oral administration of about 1 mg/kg body weight to 7 subjects. Plasma half life in healthy subjects was 1.9–2.1 h, and 2.7–8.6 h in patients during the period 4–9 hrs after dosing. Cumulative excretion in urine was 67–79% of the dose during 31–37 hrs in 6 subjects; one patient with renal disease was found to excrete only 25.8% of dose during 24 hours. Renal clearance of hydroflumethiazide was higher in the healthy subjects (0.29–0.44 1 h−1 kg−1) than in the patients (0.040–0.15 l h−1 kg−1). Plasma half life of hydroflumethiazide was not closely correlated with renal clearance of the drug, which suggests that other factors may play a role in determining plasma half life.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 355-357 
    ISSN: 1432-1041
    Keywords: Nitrazepam ; placental transfer ; pharmacokinetics ; plasma levels ; protein binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Six women from 14 to 17 weeks pregnant, and 12 woman from 36 to 40 weeks pregnant, were given nitrazepam 5 mg orally about 12 h before legal abortion by hysterotomy in the former group and elective caesarean section in the latter group. The concentration of nitrazepam was determined by gas-liquid chromatography. Binding to plasma proteins was evaluated by separation of the protein-free fraction by ultracentrifugation. In the first group (early pregnancy) the level of nitrazepam was found to be lower in the fetal than in the maternal circulation. The concentration in amniotic fluid was still lower. In the latter group (late pregnancy) the concentration both of unbound and total nitrazepam in maternal and fetal plasma were in equilibrium, which indicated an increase in transplacental transfer in late pregnancy. The percentage of unbound nitrazepam in both cases was 12%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 383-386 
    ISSN: 1432-1041
    Keywords: Benzodiazepine ; temazepam ; pharmacokinetics ; bioavailability ; hard and soft gelatine capsules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma levels of temazepam were determined in healthy subjects after single oral administration of soft and hard gelatin capsules, and after 7 consecutive night-time doses in soft capsules. Absorption from soft gelatin capsules was significantly faster and produced earlier and higher peak plasma levels. The two pharmaceutical forms did not show any significant difference in relative availability. The apparent half-life of temazepam after night-time administration was significantly shorter than after morning administration, but no change in half-life was observed between the first and seventh night-time doses.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 387-392 
    ISSN: 1432-1041
    Keywords: Digoxin ; β-methyldigoxin ; prolonged administration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Five healthy volunteers received digoxin 0.4 mg or β-methyldigoxin 0.4 mg i. v., daily for 14 days, in a randomized cross-over arrangement. By monitoring minimal plasma concentrations during multiple dosing, it was found that the steady state pharmacokinetics of digoxin and β-methyldigoxin could be estimated even better by a one-compartment than by a two-compartment model. The following mean parameters were calculated: the half life of digoxin of 1.54±0.31 days was significantly shorter than the half life of 2.29±0.34 days for β-methyldigoxin. The distribution volume of 807±187 liters for digoxin was not significantly larger than the 735±227 liters for β-methyldigoxin. Renal digoxin clearance of 191±25 ml/min was significantly higher than both the renal clearance of β-methyldigoxin of 111±23 ml/min and also the creatinine clearance, which indicates tubular secretion of digoxin. There was a 2.8-fold accumulation of β-methyldigoxin injected once a day, which was significantly higher than the 1.8-fold accumulation of digoxin.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 451-456 
    ISSN: 1432-1041
    Keywords: Bioavailability ; carbamazepine ; elimination ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The time-courses of plasma carbamazepine concentrations were followed in six apparently healthy adult subjects who, at different times, took single oral drug doses of 200, 400, 500, 600, 700, 800 and 900 mg. There were some suggestions of impaired bioavailability of the drug when given in tablet form. The following values were obtained for various pharmacokinetic parameters:k abs =0.176±0.209 h−1;k=0.0203±0.0055 h−1; T1/2=37.5±13.1 h; VD=0.825±0.1041 · kg−1; Clearance=0.0163±0.0061 l · kg−1. The elimination rate constant showed a statistically significant increase with increasing drug dose. This may help explain the clinical observation that the rate of rise of steady state plasma carbamazepine concentrations tends to decrease with dose increase in patients taking carbamazepine alone.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 19-25 
    ISSN: 1432-1041
    Keywords: Diabetes mellitus ; sulfonylurea ; glibenclamide ; pharmacokinetics ; repeated administration ; deep compartment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Six maturity onset diabetic patients took glibenclamide 5 mg by mouth, every morning 10 min before a standard breakfast. Serum levels of immunoreactive glibenclamide, glucose and immunoreactive insulin were measured repeatedly on the first and 15th days of treatment. Measured glibenclamide blood levels were in close agreement with an analogue computer simulation of data obtained from healthy volunteers: there was no accumulation of drug in the blood, but there was strong evidence for the existence of a slowly equilibrating “deep” compartment. Considerable insulin release and correction of the breakfast-induced hyperglycaemia were observed immediately after administration of the drug, as well as 5 h later, at lunch time. The clinical significance of blood levels of glibenclamide, as well as the correlation of pharmacokinetics with pharmacodynamics, are discussed in the light of these results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 57-64 
    ISSN: 1432-1041
    Keywords: General equation ; pharmacokinetics ; first pass effect ; extra-hepatic drug elimination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A general expression for the ratio of areas below the blood concentration-time curves after intravenous and oral drug administration is derived. This derivation does not require the assumption of a specific compartmental model to describe drug distribution within the body. Similarly an expression for the amount of drug metabolised in the liver is derived. The latter expression is used to estimate the extent of extra-hepatic drug elimination from the body.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 51-56 
    ISSN: 1432-1041
    Keywords: Antidepressive agent ; protriptyline ; plasma concentration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma levels of protriptyline have been determined in 30 depressed female patients undergoing antidepressant therapy. After 3 1/2 weeks treatment at dosage levels of 40 mg/day, protriptyline plasma levels ranged from 430 to 1430 nmol/l. During this period only two-thirds of the subjects had definitely achieved asymptotic concentrations. Single dose studies in 5 volunteers suggest that the volume of distribution of protriptyline shows little intersubject variation. The half life of the drug, however, may vary appreciably from subject to subject, ranging from 54 to 198 h. The effects of two sedatives on mean protriptyline plasma levels have been determined. Mean plasma levels for nitrazepam recipients are indistinguishable from those for patients receiving no night sedation. The mean plasma levels for a group of patients receiving sodium amylobarbitone were significantly reduced. The problem of choice and early adjustment of dosages in order to achieve satisfactory plasma levels is discussed. For practical purposes it is suggested that early values may be of predictive significance in allowing early dosage adjustments to be made.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 473-477 
    ISSN: 1432-1041
    Keywords: Salicylate ; aspirin ; indomethacin ; pharmacokinetics ; coeliac disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma concentrations of salicylate and indomethacin were measured after a single oral dose of aspirin (600 mg) and indomethacin (50 mg) in twelve starved normal subjects and twelve adult patients with coeliac disease. The absorption of salicylate in the coeliac patients was faster than in the normal subjects. The plasma concentration/time curve of indomethacin in both groups was similar during the absorption phase, but there were significant differences between the groups in its elimination. The abnormal absorption pattern of salicylate in coeliac disease does not appear to be related to its pKa. Possible causes of the difference in salicylate absorption include changes in gastric emptying or altered small intestinal permeability.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 205-208 
    ISSN: 1432-1041
    Keywords: Cetiedil ; vasodilator ; anticholinergic drug ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Cetiedil, a new vasodilating drug with anticholinergic properties, was shown to be metabolised very rapidly in man after intravenous and oral administration of the14C-compound. Higher concentrations of labelled compound after oral than after intravenous administration at the same sampling time, and proportional differences in urinary excretion, suggest that metabolic handling of the drug differs depending on the route of administration. Experiments in which inhibition of saliva secretion was measured indicated that (an) active metabolite(s) probably was (were) responsible for the action of the drug. As an anticholinergic drug, cetiedil is at least 400 times weaker than atropine.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 221-227 
    ISSN: 1432-1041
    Keywords: Cefuroxime ; cephalosporin antibiotics ; intravenous injection ; pharmacokinetics ; volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Cefuroxime, a new cephalosporin antibiotic which is stable to most β-lactamases produced by Gram-negative bacteria, was given by bolus intravenous injection to six volunteers in doses of 500 mg and 750 mg. The concentrations of cefuroxime in serum and urine were measured at pre-determined times after injection and the data analysed by a two-compartment open system model. A serum concentration of 8 µg/ml was exceeded for 100.3 min (±18.3) after a 500 mg dose and for 144.5 min (±19.8) after 750 mg. The ultimate serum half-life was 1.1 h. Excretion of cefuroxime in the urine was almost complete in 24 h, the clearance being 150 ml/min/1.73 m2. About 45% was excreted through the renal tubules. The injections were well tolerated and no changes in haematological or biochemical values were seen. The resulting data are compared with those published for some other cephalosporins. It is concluded that the favourable pharmacokinetics, especially the high concentrations of unbound cefuroxime in the serum, are likely to aid effective therapy of human infection caused by sensitive bacteria.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 91-99 
    ISSN: 1432-1041
    Keywords: Disopyramide ; plasma concentration ; cardiodepressant drugs ; ventricular arrhythmia ; ventricular tachycardia ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Ten patients with various heart diseases and ventricular arrhythmia received a single oral dose of disopyramide (DE) 200 mg. The ECG was recorded continuously for about 50 h from 2–4 h before drug administration. A statistically significant reduction in the number of ventricular ectopic beats (VEBs) was seen 1.0–3.5 h after drug intake; the average number of VEBs per 30 min decreased from 317 during the control period to 92 by 1.0–3.5 h after treatment and if one patient who did not respond is excluded, the corresponding figures were 272 and 14, respectively. Consecutive VEBs were seen in seven patients before DE was given and decreased significantly (p〈0.05) 1.5–5.5 h after drug administration. There was no change in the PQ interval, the QRS interval showed a slight increase, whereas the QT interval was prolonged 0.5–4 h after administration of DE. A specific gas chromatographic method was used for DE assay in plasma and urine. Absorption was rapid in all patients. Urinary excretion during the first 48 h after drug intake varied between 35 and 75%. The lowest effective antiarrhythmic concentration estimated in six patients ranged from 1.4 to 7.0 µg/ml. β-Phase half-life in five patients was between 10.3 and 22.1 h.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 73-76 
    ISSN: 1432-1041
    Keywords: Quinidine ; pharmacokinetics ; non-linearity ; dose-dependent pharmacokinetics ; steady state plasma level ; oral administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Quinidine was administrated orally to five healthy male volunteers. Doses of 0.2 g t. i. d., 0.3 g t. i. d. and 0.4 g t. i. d. were given for five days with at least four weeks between each test period. The plasma concentration of quinidine was measured before the morning dose on Days 2–5 of treatment, and 1, 2, 4 and 8 h after the morning dose on the 5th day. There was not a linear relationship between the increase in dose and the increase in plasma concentration of quinidine. A dose increase of 50% from 0.6 to 0.9 g quinidine sulphate per day resulted in an increase in steady state concentration of 94%. A further 33% increase in dose, from 0.9 to 1.2 g daily, resulted in a 55% increase in the steady stae concentration of quinidine. The results demonstrate dose-dependent pharmacokinetics for quinidine. Possible explanations for the nonlinear pharmacokinetics are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 117-123 
    ISSN: 1432-1041
    Keywords: Methyldopa ; radioactive label ; pharmacokinetics ; metabolism ; healthy volunteers ; intravenous and oral administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of 2-14C-L-α-methyldopa have been investigated in five healthy volunteers following intravenous and oral administration. In the intravenous study a bi-phasic plasma concentration curve was found both for chemically determined α-methyldopa and for radioactivity. The plasma level of radioactivity differed significantly from chemically determined drug, a pattern which was also found in urine. This suggests the presence of unidentified metabolite(s). The difference between plasma disappearance and urine recovery of α-methyldopa and radioactivity during the first 4 h after injection suggests distribution to an extravascular compartment. Plasma half-lives of total radioactivity and of unchanged drug were calculated. In three subjects, pharmacokinetic parameters for a two-compartment open body model were calculated from urine and plasma data. Urinary recovery of radioactivity was almost complete within 48 h after intravenous administration. After oral administration, however, only about 40 per cent of the radioactive dose was recovered in the urine, and it contained approximately equal amounts of unconjugated methyldopa, acid-labile conjugated methyldopa and unidentified metabolite(s). The acid-labile conjugate was found only after oral administration, which supports the theory of a mucosal conjugation process. The lack of acid-labile conjugated drug either in the plasma or urine after intravenous injection indicates that there is no enterohepatic circulation of this drug.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 283-286 
    ISSN: 1432-1041
    Keywords: Paracetamol ; Acetaminophen ; pharmacokinetics ; first-pass elimination ; intravenous administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma paracetamol concentrations were measured in 6 volunteers after single intravenous (1000 mg) and oral (500 mg, 1000 mg and 2000 mg) doses of the drug. Paracetamol levels declined multiphasically with a mean clearance after intravenous administration of 352±40 ml/min. A two-compartment open model appeared to describe the decline adequately. Comparison of the areas under the plasma concentration-time curves (AUC) indicated that oral bioavailability increased from 0.63±0.02 after 500 mg, to 0.89±0.04 and 0.87±0.08 after 1000 mg and 2000 mg, respectively. As a consequence of the incomplete bioavailability of paracetamol, as well as its multicompartmental distribution, accurate estimates of its distribution volume and clearance cannot be obtained if the drug is given orally. However, an estimate of its total plasma clearance may be derived from the AUC after a 500 mg oral dose.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 329-335 
    ISSN: 1432-1041
    Keywords: Digoxin ; pharmacokinetics ; two-compartment model ; radioimmunoassay ; neonates ; infants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The distribution and elimination of intravenous digoxin were investigated in seven neonates and infants with heart failure. Serum digoxin concentrations during a 24 h period were determined by radioimmunoassay, using125I as tracer. The serum values declined biexponentially after the injection and could be fitted to a two-compartment open model by non-linear least-squares regression. The calculated mean half-lives of the distribution (alpha) phase in neonates and infants were 37 and 28 min, respectively. The mean half-life of the elimination (beta) phase in neonates was 44 h, as compared to 19 h in infants. The mean volume of the central compartment and the mean volume of distribution at steady-state were calculated to be 1.3 and 9.9 l/kg, respectively; no significant differences between neonates and infants were found. The relation between these volumes indicates that digoxin is extensively distributed in tissues. The steady-state distribution volumes of digoxin in neonates and infants exceed those reported in adults. The larger volume of distribution might explain in part why infants with cardiac insufficiency require larger doses of digoxin than adults (on a mg/kg body weight basis) to obtain the same serum concentrations. Elimination of digoxin from the body was slower in neonates than in infants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 351-358 
    ISSN: 1432-1041
    Keywords: Phenprocoumon ; protein binding ; pharmacokinetics ; pharmacodynamics ; drug therapy ; myocardial infarction ; chronic disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In nine patients, the synthesis rate Rsyn of the vitamin K-dependent clotting factors was calculated from changes in prothrombin-complex activity after intravenous administration of a synthesis-blocking dose of phenprocoumon (PPC). The biological half-life of PPC was between 2.70 and 7.01 days. No correlation was found between the level of the free fraction of this strongly protein-bound drug and its biological half-life. There was a positive correlation (p〈0.01) between the size of the free fraction of PPC and the apparent volume of distribution of the drug. Four of the patients had had an acute myocardial infarction and they showed increased sensitivity to PPC. In them the plasma level of PPC sufficient to reduce Rsyn to 50% of R°syn was significantly lower, and the depression of individual vitamin K-dependent coagulation factors was more pronounced and prolonged, than in five other patients with chronic disease. The degradation rate of coagulation factors was also found to be higher in the patients with acute myocardial infarction. In four patients with chronic disease, anticoagulant therapy with PPC was continued in the out-patient clinic. The calculated oral maintenance dose of PPC, assuming complete absorption, first-order elimination kinetics and a linear relationship between the pharmacological effect and the logarithm of the PPC-plasma concentration, showed good agreement with the dose actually found to produce the desired PP% level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 11 (1977), S. 367-375 
    ISSN: 1432-1041
    Keywords: Acenocoumarol ; excretory balance man ; pharmacokinetics ; biotransformation ; plasma protein binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption, biotransformation and elimination of the anticoagulant acenocoumarol, 3-[α- (4′-nitrophenyl)-β-acetylethyl]-4-hydroxycoumarin, have been studied by oral administration of 12 mg of a14C-labelled preparation to two male volunteers. Absorption from the gastro-intestinal tract was rapid and the plasma concentration of unchanged drug reached a maximum of 169 and 412 ng/ml, respectively, after 3 hours. The elimination half-life in the two subjects, calculated from the decline between 6 and 24 h, was 8.7 and 8.2 hours. A constant proportion of 98.7% of the drug was bound in vitro to serum proteins over a concentration range of 0.021–8.34 µg/ml, with little interindividual variation. The major portion of the binding was to human serum albumin (97.5%) at two classes of binding sites: association constant K1=1.04×105 l/mole (n1=1) and K2=5.55×103 l/mole (n2=4). In addition to unchanged acenocoumarol, four metabolites were determined in plasma by isotope dilution techniques: the amino-, acetamido-, alcohol1- and alcohol2-metabolites. Of them, the amino-metabolite showed the highest concentration, namely 278 ng/ml, after 6 h in Subject A, and 163 ng/ml after 10 hours in Subject B. Judged from the integrated concentrations, the compounds analyzed accounted for 76 and 89%, respectively, of the total radioactivity in plasma. All the metabolites detected in plasma showed anticoagulant activity when tested in mice. The quantities of the metabolites excreted in urine from 0–120 hours were (Subject A/Subject B): acenocoumarol 0.3/0.2%, amino-metabolite 12.3/7.7%, acetamido-metabolite 19.0/11.1%, alcohol1-metabolite 4.6/9.0%, alcohol2-metabolite 1.7/4.4%, 6-hydroxy-metabolite 6.9/18.3% and 7-hydroxy-metabolite 14.0/22.2%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 297-303 
    ISSN: 1432-1041
    Keywords: Hydrochlorothiazide ; pharmacokinetics ; dose/response relationship ; natriuresis ; kaliuresis ; calciuresis ; magnesiuresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Hydrochlorothiazide (hct) was administered orally in four different doses (12.5, 25, 50 and 75 mg), to eight healthy volunteers. Plasma and urine concentrations of hct were determined by GLC. Maximal plasma levels were found at 1.5–5 h, and averaged 70, 142, 260 and 376 ng × ml−1 respectively. The peak plasma levels and AUC0→9h of hct were highly correlated (p〈0.001) with the dose. The decline in the plasma curve was biphasic in those experiments in which the plasma levels of hct could be determined for at least 24 h. The half life of the slower phase lay between 5.6 and 14.8 h. The urinary recovery of hct, which represented the gastrointestinal absorption, averaged 65 to 72 per cent of the dose. The mean renal plasma clearance did not vary with the dose and averaged 319 to 345 ml × min−1. The diuresis during the 10 h after hct 12.5 mg exceeded that after placebo by a mean of 800 ml. The diureses was not increased further after higher doses of hct. The maximal natriuretic effect (+ 100 mmol), too, was found after the 12.5 mg dose. The excretion of potassium, however, rose with increasing doses; the maximal increment, after 75 mg hct, averaged 25 mmol. The excretion of calcium was significantly increased after 50 mg hct (+ 0.6 mmol). The maximal effect on magnesium excretion occurred after 25 mg hct (+ 0.5 mmol). In healthy volunteers there was no correlation between peak plasma level of hct or AUC0→9h and the renal excretion of water and electrolytes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 12 (1977), S. 305-310 
    ISSN: 1432-1041
    Keywords: Phenobarbital ; pharmacokinetics ; neonates ; infancy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In 14 neonates 1–4 weeks old, 30 babies aged 1–12 months, and 7 infants of 1–5 years of age, the serum levels of phenobarbital were determined by a gas chromatographic micro-method after intravenous injection of phenobarbital 5–10 mg per kg body weight. It was possible to calculate the pharmacokinetic parameters using a two compartment open model. The distribution volumes within the individual age groups and the rate constants k12 and k21 showed no significant differences, but the elimination half-life was significantly longer in neonates (118.6±16.1 h) than in babies (62.9±5.2 h) or infants (68.5±3.2 h).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    ISSN: 1432-1041
    Keywords: Tolmetin ; pharmacokinetics ; bioavailability ; antacid ; oral dose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The purpose of this study was to determine whether a concomitant single dose of antacid or multiple doses of antacid administered prior to, and with tolmetin, alter the pharmacokinetics of tolmetin when the drug was administered as a commercially available tablet containing tolmetin sodium. The possible effects of the antacid on plasma concentrations and urinary excretion of tolmetin and its major metabolite were evaluated following administration of: (a) tolmetin sodium alone; (b) antacid four time a day for three days prior to a single dose of tolmetin sodium, with continuation of the antacid during the day tolmetin was given; and (c) co-administration of single doses of tolmetin sodium and antacid. The twenty-four subject study was of the crossover type. There were no significant differences among treatment means for: (i) peak plasma concentrations of both tolmetin and metabolite, (ii) AUC 0–8 h and AUC 0-∞ for both tolmetin and metabolite, (iii) time to peak plasma concentration for both tolmetin and metabolite, (iv) plasma concentrations of both tolmetin and the metabolite at all sampling times (except for tolmetin at 2 h), (v) renal clearance of both tolmetin and its metabolite, and (vi) the amount of metabolite excreted in the 0–24 h urine. There were small, but significant, differences among amounts of tolmetin excreted in the 0–24 h urine. Semilogarithmic plots of both tolmetin and metabolite plasma concentrations past the peak concentrations were curved over the entire 8-h observation period; although the elimination half-life of tolmetin has been reported to be about one hour, the half-life most probably exceeds 2.6 h in most subjects. The results of this study indicate a lack of a significant drug-drug interaction between the non-steroidal anti-inflammatory agent, tolmetin sodium, and a commonly used antacid, which is a mixture of magnesium and aluminium hydroxides.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 112 (1977), S. 123-126 
    ISSN: 1432-072X
    Keywords: Bandeiraea simplicifolia ; Schizosaccharomyces pombe ; Colloidal gold ; Cytochemistry ; α-Galactomannan-lectin ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Galactomannan was localized by scanning and transmission electron microscopy on the cells and cell walls of Schizosaccharomyces pombe. The markers were prepared from colloidal gold granules labelled with an α-galactopyranosyl-binding lectin isolated from the seeds of Bandeiraea simplicifolia. Part or all of this α-galactomannan was present in the outer layer of the cell wall and was uniformly distributed even on the fission scars.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 176 (1977), S. 493-504 
    ISSN: 1432-0878
    Keywords: Pancreas ; Acinar cells ; Cell surface ; Dissociation ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pancreatic acinar cell surfaces have been studied by SEM with a dissection technique and correlated with results obtained by TEM. The SEM results demonstrate characteristic arrangement of microplicae which in some areas are densely packed. In many areas, the microplicae are distributed in such a manner that they create zones with typical geometrical shapes and show a relatively smooth surface. These smooth areas may coincide, as indicated by correlated TEM results, with the limits of intimate contact between adjacent acinar cells which, in turn, represent part of the junctional complex. Another aspect revealed by these SEM preparations concerns the presence of groups of densely packed microplicae, arranged in regular rows and distributed along some grooves and/or infoldings of the cellular surface. On the basis of SEM and TEM information, it is likely that these structures correspond to intercellular (and possibly, in some cases, intracellular) canaliculi which topographically form a kind of extensive microlabyrinthine arrangement running along all the cell sides. One final point revealed by fractured samples concerns the finding of spherical zymogen droplets within the vesicles of the Golgi complex. Because in many scanning images these vesicles appear connected by small openings, it is suggested that they may represent a system of intercommunicating chambers (vacuoles) through which the zymogen droplets can be continuously accumulated and discharged into the acinar lumen.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 177 (1977), S. 307-316 
    ISSN: 1432-0878
    Keywords: Third ventricle ; Mature monkeys ; Scanning electron microscopy ; Ependyma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Surface features of the ependymal lining of the third ventricle in mature male and female monkeys have been investigated with scanning electron microscopy (SEM). Broad aspects of third ventricular morphology from three species of monkey are similar regardless of sex. The lateral walls are heavily ciliated whereas the ventral floor and most ventral parts of the lateral walls are not. Clumps of cilia on the lateral walls are so dense that underlying surface details are usually obscured. There is a transition zone between the ciliated lateral wall and nonciliated ventral floor. The floor and lower part of the lateral walls of the third ventricle exhibit a characteristic polygonal pattern upon which surface specializations such as microvilli, blebs and polymorphous membrane protrusions are superimposed. Ependyma of the choroid plexus of the third ventricle also display membrane specializations. Supraependymal cells are more visible in nonciliated regions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    ISSN: 1432-0878
    Keywords: Blood vessels ; High voltage electron microscopy ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The luminal surface features and Junctional complexes from developing blood vessels in the rat central nervous system have been studied by high-voltage electron microscopy and scanning electron microscopy. Developing blood vessels exhibit three types of luminal projections; marginal folds or ridges at Junctional complexes, ridges not at Junctional complexes and microvilli. Both types of ridges are associated with troughs or depressions in the luminal surface of the endothelial cell. Those ridges not associated with Junctional complexes take part in the production of enclosed tunnels in the endothelial cell cytoplasm. Fusion of the external leaflets of Junctional complexes between adjacent endothelial cells occurred, initially, near the luminal surface of the blood vessel with other small fusion sites forming in the direction of the basal lamina secondarily. Further fusion activity to produce the zonula occludens type junction appeared to spread outwards from the smaller fusion sites.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    ISSN: 1432-0878
    Keywords: Pineal organ ; Uroloncha domestica (Aves, Passeriformes) ; Photoreceptor-like cells ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pineal organ of the lovebird, Uroloncha domestica, bulbous, cup-shaped and elongated outer segments of photoreceptor-like pinealocytes are demonstrated by scanning electron microscopy. These scarce outer segments, 4–11 μm in length, extend into the pineal lumen. The present structural observations speak in favor of photosensitive pinealocytes in the pineal organ of Uroloncha domestica. The relation of the photoreceptor-like pinealocytes to acetylcholinesterase-positive nerve cells and a nervous connection between the pineal and the brain indicate that the pineal organ of this passeriform species may be the site of neuroendocrine and photoreceptive functions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 5 (1977), S. 513-531 
    ISSN: 1573-8744
    Keywords: pharmacokinetics ; nonlinear regression ; curve fitting ; computer program ; time sharing ; modeling ; weighting ; least squares ; parameter estimation ; discrimination between models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The problems of curve fitting and modeling in pharmacokinetics are discussed. A new nonlinear regression program FUNFIT, written for interactive time sharing, is presented which should be more reliable than programs based on the Gauss-Newton or other related gradient methods. The new program and the well-established program NONLIN were tested on two linear models using human plasma drug level data. FUNFIT found a substantially better solution than NONLIN in the majority of the cases.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 5 (1977), S. 335-358 
    ISSN: 1573-8744
    Keywords: pharmacokinetics ; perfusion models ; sampling ; parameter estimation ; computer program ; Org GB 94 ; mianserin ; Org GC 94
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A mathematical treatment of the influence of sampling on drug kinetics in liver perfusion is presented. Based on the derived equations, a Fortran IV computer program (PERFUS) is given, by which the time course of drug concentrations can be simulated for any sampling scheme. The simulations show that the withdrawal of large samples from the reservoir, i.e., larger than 5% of the reservoir volume, results in substantially biased parameters for drugs that are rapidly distributed and/or metabolized. For the fitting of empirical data, a Fortran IV computer program is given, based on BMDX85 nonlinear least squares by Gauss-Newton iterations. This program (PERFIT) estimates model parameters corrected as if no sampling had occurred, no matter how distorted the drug disappearance curve mày be as a result of sampling or due to degeneration of the two-compartment model into a one-compartment model. The conditions under which this degeneration occurs are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 5 (1977), S. 111-122 
    ISSN: 1573-8744
    Keywords: hepatic clearance ; extraction ratio ; local anesthetics ; pharmacokinetics ; lidocaine ; bupivacaine ; etidocaine ; cardiovascular effects of local anesthetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two independent methods of calculating hepatic drug clearance were applied to data from studies of the human pharmacokinetics of lidocaine, bupivacaine, and etidocaine. Within experimental limitations, agreement was good between estimates obtained by measurement of areas under blood drug concentration-time curves after rapid intravenous injection and by direct measurement of arterial and hepatic venous drug concentrations. Apparent hepatic extraction ratios of the agents followed the order etidocaine (∼0.73)/s〉lidocaine (∼0.68〉bupivacaine (∼0.37).Pharmacokinetic implications of increases in hepatic blood flow induced by the agents are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    ISSN: 1573-8744
    Keywords: chlordiazepoxide ; benzodiazepine ; two-compartment model, biopharmaceutics ; pharmacokinetics ; single dose ; routes of administration ; intravenous ; intramuscular ; oral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Single 30- mg doses of chlordiazepoxide HCl were administered to six healthy human subjects by the intravenous, oral, and intramuscular routes. Plasma concentration- time curves following intravenous administration were satisfactorily described by a biexponential equation consistent with a two-compartment open model system. Mean values of half-lives for the so-called distribution and elimination phases were 0.252 and 9.39 hr, respectively. The mean values for the volume of the central compartment (V 1) and volume of distribution $$(V_{d_\beta } )$$ were 18.0 and 30.9% of body weight, respectively. Following oral administration, the drug was rapidly and completely absorbed. Absorption was first order (t1/2≈27 min), and three of the six subjects showed a discernible lag time of approximately 20 min. Drug absorption following intramuscular administration was comparatively slow. A two- compartment “muscle model” comprised of precipitated and solubilized drug in the muscle was found to satisfactorily characterize the absorption process following administration by this route.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 5 (1977), S. 421-433 
    ISSN: 1573-8744
    Keywords: methotrexate ; pharmacokinetics ; model ; computer ; cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The infusion of high doses of methotrexate followed by folinic acid rescue is clinically useful against a variety of tumors. We studied the plasma pharmacokinetics of high-dose methotrexate infusions in patients with advanced cancer and devised a compartmental, kinetic model. our model is based on an earlier, mathematical model which describes the pharmacokinetics of moderate- to- high-dose methotrexate given as a single, intravenous injection. Mathematical equations for our model were solved on a UNIVAC1108 computer with the SAAM program. Seven compartments represent the distribution spaces for methotrexate and its metabolites. The transport of drug into and out of compartments is described by first-order differential equations. A nonlinear, concentration-dependent function is used for renal excretion with saturation of secretory and reabsorption mechanisms by methotrexate. Our model accurately depicts the pharmacokinetics of nine courses of therapy in five patients. The model can also be used to simulate the kinetics of methotrexate for patients with impaired renal function.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    ISSN: 1573-8744
    Keywords: gentamicin ; tissue distribution ; pharmacokinetics ; two-compartment modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Gentamicin pharmacokinetics was examined in a group of 47 patients with stable renal function treated an average of 10 days for severe infection. Serum concentrations rose continually during treatment, and declined in two phases after the drug was stopped, with a mean half-life of 112hr (range 27–693 hr) in the second phase. A two-compartment model was used to describe the biphasic decline in serum concentrations and to calculate the amount of drug in the tissue compartment at all times during and after treatment. Predicted tissue amounts of gentamicin rose continually on multiple dosing in all patients. In six patients who died, postmortem tissues were obtained to quantitate recovery. In all cases, the predicted amount of gentamicin in tissues was in close agreement with the amount recovered at autopsy. Tissue distribution and accumulation constitute a major reason for variability in gentamicin pharmacokinetics and explain both the rising peak and trough serum concentrations and the prolonged detection of gentamicin in serum and urine after the drug is stopped.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    ISSN: 1573-8744
    Keywords: chlordiazepoxide ; benzodiazepine ; two-compartment model ; multiple dosing ; pharmacokinetics ; biopharmaceutics ; metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Eight healthy male volunteers received chlordiazepoxide HCl orally at a dosage of 10 mg every 8 hr over a period of 21 days. On day 22, the regimen was changed to 30 mg every 24 hr for an additional 15 days. Plasma concentrations of chlordiazepoxide and its metabolites desmethyl-chlordiazepoxide, demoxepam, and desoxydemoxepam were measured during 14 of the 36 treatment days. Chlordiazepoxide plasma concentration- time data were consistent with first-order absorption and complete bioavailability. The harmonic mean absorption half-life was 12.3 min. Disposition of chlordiazepoxide was described by a two-compartment open model with a harmonic mean terminal exponential half-life of 10.1 hr. Average steady — state plasma levels of chlordiazepoxide, desmethylchlordiazepoxide, and demoxepam were approximately 0.75, 0.54, and 0.36 μg/ml, respectively.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    ISSN: 1432-0878
    Keywords: Lateral ventricle, rat ; Hydrocephalus ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ependyma of the lateral ventricle of rats with hereditary hydrocephalus was studied using scanning electron microscopy. Normal rats from the same litters were used as control animals. The surface morphology of the lateral ventricle of normal rats corresponded to results reported by other authors. The most prominent changes in the surface morphology of the ependyma of the hydrocephalic rats were seen in the cilia. They were shortened, fewer in number and clumped or matted. The surface of the ependymal cells was flattened and contained small, irregular projections. The number of large supraependymal cells, regarded as neurons, appeared to have diminished in the hydrocephalic rats. The number of supraependymal macrophages was greatly increased in these rats, suggesting the existence of an ependymitis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 178 (1977), S. 267-278 
    ISSN: 1432-0878
    Keywords: Ciliated epithelium, frog ; Cilia ; Coordination ; Mucous transport ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The palate epithelium of the frog was examined by scanning electron microscopy, light microscopy and high speed cine micrography. The cilia remain stationary for much of the time in the end-of-effective stroke position. Each beat cycle begins with a forwardly-directed recovery stroke lasting about 60 ms, followed by an effective stroke towards the oesophagus lasting about 12 ms. Activity can often be correlated with the presence of mucus, which is carried as strands on the tips of the ciliary effective strokes whilst the recovery strokes move beneath the mucus. Coordination of ciliary activity was very variable; local antiplectic metachrony of the recovery strokes could almost always be seen, and on very active epithelia effective strokes were associated with approximately diaplectic waves (either to left or right), but any particular pattern of coordinated activity was transient and quickly transformed to another pattern. Beating and coordination of these short cilia were compared with those of cilia propelling water.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 178 (1977), S. 375-384 
    ISSN: 1432-0878
    Keywords: Taste buds ; Fishes ; Neuroepithelium ; Microvilli ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary External taste buds abound on barbels of the adult catfish Corydoras arcuatus. When examined by scanning electron microscopy, they are visualized as a series of punctate, conical elevations projecting from the general surface epithelium. All taste buds were found to be of one type. Both their external and internal surface features could be clearly elucidated on intact barbels and in barbels fractured transversely at various positions along their length. An extensive nerve terminal network penetrates the base of each taste bud. Two populations of elongated cells bearing prominent microvilli project through the central pore at the tip of each bud. One set of microvilli is thicker, longer and more club-shaped than its counterpart. While both are randomly distributed within each central pore, the small, short microvilli appear to outnumber the larger ones. A third population of cells, devoid of any apical microvilli, was also seen in some of the taste buds examined internally. These cells do not project to the external surface and are interpreted as “basal” cells described in previous light and transmission electron microscope studies of taste buds in other vertebrate species. The functional significance of some of these morphological findings is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    ISSN: 1432-0878
    Keywords: Hypophysis, pars distalis ; Bufo bufo (L.) ; Vascularization ; Corrosion casts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vascularization of the pars distalis of the hypophysis of the toad, Bufo bufo (L.), was studied by the traditional method of injecting a mixture of India-ink and gelatine into the circulatory system of the head via the arteria carotis communis. Further, methyl-methacrylate corrosion casts of the brains were made; the hypothalamo-adenohypophysial region of these corrosion casts was studied with the scanning electron microscope. The results showed that the portal vessels which arise from the median eminence do not supply distinct areas in the pars distalis as is supposed by the point-to-point-hypothesis. The portal vessels enter the ventro-median region of the pars distalis and branch off into a three-dimensional network of the secondary capillary plexus of the pars distalis. The plexus is made up mostly by four- to six-sided meshes. This angioarchitecture guarantees an optimal supply of the glandular cells of the pars distalis with nutritional factors and releasing hormones, on the one hand, and facilitates the removal of the hormones which are released by these cells, on the other hand. The venous drainage of the pars distalis is exerted mainly by two large veins, which bilaterally leave the dorso-lateral region (venous pole) of the pars distalis and by a few small veins, which drain into the wide, sinus-like vessel, which curves around the dorso-caudal region of the pars distalis and joins bilaterally the vena hypophysea transversa.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 183 (1977), S. 531-539 
    ISSN: 1432-0878
    Keywords: Brain ventricles ; Armadillo ; Ependyma ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The scanning electron microscope was used to survey the brain ventricular system of the female armadillo (Dasypus novemcinctus) with emphasis on the third ventricle. The walls of the lateral ventricles, aqueduct, and fourth ventricle are covered by long cilia. In the lateral ventricle, the cilia are arranged in groups; but in the aqueduct and fourth ventricle, they are evenly placed over the cellular surfaces. The ependymal cells of the third ventricle are densely ciliated except for the organum vasculosum and infundibular recess. The non-ciliated luminal surface of these areas has a pebblestone appearance punctuated by numerous microvilli and two types of supraependymal cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 179 (1977), S. 225-234 
    ISSN: 1432-0878
    Keywords: Marginal ruffles ; Fibroblast-like cells ; Scanning electron microscopy ; Transmission electron microscopy ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary LW13K2 cells, a clone of a spontaneously in vitro transformed derivative of embryonic Lewis rat fibroblastic cells, were studied by phase contrast cine-light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ruffles found at the advancing edge of cells grown on glass substrates in vitro form and recede in a period of less than one min if they do not make an attachment of the substrate. If they fail to make an attachment they may form pinocytotic channels near the leading edge as described by Price (1972) and/or collapse, generally backwards, towards the cell body. The ‘spines’ which appear to reinforce the membranous ruffles are the last structures to disappear, and accumulate in an irregular array behind the ruffling edge; this area is behind that in which pinocytosis occurs. In comparison with the sparse numbers of ribosomes found in the trailing edge, they are present in notable concentrations near the leading, ruffling edge of the cell. No membrane vesicles have been found in or near the ruffling edges at the ruffle-spine concentration zone.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    ISSN: 1432-0878
    Keywords: Hypophysis, pars intermedia ; Bufo bufo (L.) ; Vascularization ; Corrosion casts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vascularization of the pars intermedia of the hypophysis of the toad, Bufo bufo (L.) was studied by injection of a mixture of India-ink and gelatine into the circulatory system of the head via the arteria carotis communis. Further methyl-methacrylate corrosion casts of brains were made and the hypophysial region of the corrosion casts was examined with the scanning electron microscope. The results showed that the vascularization of the pars intermedia of the toad hypophysis consists of a single-layered vascular network, which is located on the ventral surface of the pars intermedia. The network is formed by capillaries, which primarily run caudally in a fan-like manner and which show only a few cross-connections. In the rostral region of the pars intermedia this network lies rather superficially, while in the caudal region it slightly penetrates the parenchyma. The vascular network originates from vessels of the neural stalk and from wide capillaries of the rostro-ventral region of the neurointermediate junction. The venous drainage of the pars intermedia is exerted by veins, which leave the caudal region and drain into the veins leaving the venous pole of the pars distalis. The fiat, wide meshed vascular net on the ventral side of the pars intermedia, demonstrated in this study, fits into the concept that the pars intermedia of the anuran hypophysis is under the control of nerve fibers coming from the hypothalamus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 185 (1977), S. 279-283 
    ISSN: 1432-0878
    Keywords: Vocal cord epithelium (Human) ; Microridges ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelium of the vocal cord from children and adults is analysed with SEM and TEM. Scanning micrographs show that the apical cell membrane is furnished with microvilli and microridges of various patterns. The function of microridges is discussed in relation to the distribution and retention of mucus on the vocal cord.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 185 (1977), S. 387-397 
    ISSN: 1432-0878
    Keywords: Osteoclasts ; Resorption ; Bone ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Osteoclasts of the peripheral portions of the endocranial aspect of young rat parietal and frontal bones were studied by scanning electron microscopy of glutaraldehyde fixed, critical point dried specimens. These studies show Osteoclasts to have a much more complicated form than has previously been realised. Extensively branching, elongated, smooth-surfaced cells, which are for the most part elevated above the level of the surrounding bone matrix surface and sometimes above portions of osteoblasts or other osteoclasts, were identified as motile non-resorbing cells. Portions of the former and other entire cells may be embowered in Howship's lacunae, have microvilli on their dorsal surface, and are surrounded by a serrated border of microprojections which have an apparently firm attachment to the matrix surface. Osteoclasts in short term culture show additional free surface ruffles which are not encountered in specimens taken fresh from the animal. No evidence of recruitment of osteoblasts or osteocytes into osteoclasts was found. Disinterred osteocytes retained an ability to migrate from their lacunae on to surrounding bone matrix surface.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 180 (1977), S. 421-431 
    ISSN: 1432-0878
    Keywords: Ciliated cells ; Trachea ; Radiation effects ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Early effects of ionizing radiation were investigated in an experimental in vitro system using the ciliary cells of the tracheal mucous membrane of the rabbit, irradiated at 30° C and at more than 90% humidity. The changes in physiological activities of the ciliary cells caused by irradiation were continuously registered during the irradiation. The specimens were examined immediately after irradiation electron microscopically. The morphological changes in irradiated material after 10–70 Gy are compared with normal material. After 40–70 Gy, scanning electron microscopy revealed the formation of vesicles on cilia, and club-like protrusions and adhesion of their tips. After 30–70 Gy, a swelling of mitochondrial membranes and cristae was apparent transmission electron microscopically. The membrane alterations caused by irradiation are assumed to disturb the permeability and flow of ATP from the mitochondria, which in turn leads to the recorded changes in the activity of the ciliated cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    ISSN: 1432-0878
    Keywords: Hypophysis, neural stalk, pars nervosa ; Bufo bufo (L.) ; Vascularization ; Corrosion casts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The angioarchitecture of the neural stalk and the encephalo-posthypophysial portal system of the hypophysis of the toad, Bufo bufo (L.), was studied using three different methods. The neural stalk is mainly supplied by branches of the arteria infundibularis superficialis which form a widemeshed vascular network. Dorsally this network continues into the plexus of the pars nervosa. The vascularization of the pars nervosa is made up of the encephalo-posthypophysial portal system. This portal system consists of a hypothalamic branch (=portion), a mesencephalic and a mesencephalic-bulbar branch (=portion). The hypothalamic branch was found to drain the pars ventralis of the tuber cinereum as well as more dorsal regions of the diencephalon. The mesencephalic-bulbar trunk enters the hypothalamic branch. The resulting common stem of the encephalo-posthypophysial portal vein then curves around the retroinfundibular communicating artery, crosses its ventral side and runs caudally. The secondary capillary plexus of the pars nervosa is characterized by well defined capillary networks which are located at the periphery of the parenchyma of the pars nervosa, thus forming a rostral, dorsal and ventro-caudal net. The central region of the parenchyma of the pars nervosa is supplied only by main branches of the encephalo-posthypophysial portal vein. The venous drainage of the pars nervosa is via the vena hypophysea transversa.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...