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  • 1990-1994  (1,057)
  • 1980-1984
  • 1920-1924
  • 1993  (1,057)
  • Biochemistry and Biotechnology  (800)
  • Immunohistochemistry
  • pharmacokinetics
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Years
  • 1990-1994  (1,057)
  • 1980-1984
  • 1920-1924
Year
  • 101
    ISSN: 1432-1041
    Keywords: Isradipine ; Diclofenac ; pharmacokinetics ; platelet aggregation ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In this open, two-period crossover study in 18 healthy male volunteers, a single oral dose of 50 mg diclofenac was administered alone and on day 7 of multiple oral dosing of 5 mg b.i.d. isradipine to assess a possible pharmacokinetic interaction. The effect of these drugs on ex vivo platelet function was also determined. Serial blood samples were obtained over 12-hour periods on three occasions: after the single diclofenac dose; after the morning dose of isradipine on day 6 and after co-administration of both drugs on day 7 of steady-state isradipine administration. Additional samples were taken at 2 h post dose for determination of ex vivo platelet aggregation. Isradipine plasma concentrations were determined by a gas chromatographic method and diclofenac plasma concentrations by an HPLC method. The pharmacokinetic characteristics of diclofenac were unaltered during co-administration. The maximum plasma concentration of isradipine was increased 19.6% during co-administration from 5.06 to 6.05 ng·ml−1. This is not expected to be of clinical importance. Isradipine's apparent total body clearance and steady-state AUC remained unchanged. Ex vivo induced platelet aggregation was not affected by any of the treatments.
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  • 102
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 45 (1993), S. 555-558 
    ISSN: 1432-1041
    Keywords: Glucagon ; pharmacokinetics ; i.v. infusion ; intranasal spray ; intramuscular administration ; insulin-dependent diabetes mellitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of intranasal, an intravenous infusion, and intramuscular glucagon has been studied in 5 healthy subjects and 11 patients with insulin-dependent diabetes mellitus. After infusion the elimination half-life was significantly longer in diabetics (11.9 vs 6.6 min) and the apparent volume of distribution was twice as high in diabetics (0.19 vs 0.37 l·kg−1). The metabolic clearance rates were the same in the two groups (18.9 and 21.3 ml·min−1·kg−1 in controls and in diabetics) and were about twice those previously reported. After 1 mg intranasally the Cmax of immunoractive glucagon (IRG) was similar in diabetic and in healthy subjects. Administration of a higher dose (2 mg) to diabetic patients produced a higher plasma level, although not proportionately so. The AUC after 1 mg was also similar in controls and in diabetics. The elimination half-life in both groups was similar to the value found after IV infusion; it was significantly shorter in controls (5.5 min) than in diabetics (13.8 min). In both groups, mean Cmax was significantly lower than after IM glucagon, the relative bioavailability of 1 mg intranasally vs IM injection being less than 30%. After IM administration, the Cmax and AUC of IRG in controls and in diabetic patients, were identical. The apparent elimination half-life was also similar in the two groups, and was three- to four-times longer (28.6 and 31.4 min) than after infusion or intranasal administration, possibly because estimation of the t1/2 was affected by slow release of the hormone from the site of injection.
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  • 103
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 45 (1993), S. 563-569 
    ISSN: 1432-1041
    Keywords: Chlorpromazine ; metabolites ; N-oxide ; sulfoxide ; 7-hydroxy ; conjugates ; pharmacokinetics ; first pass metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A study was carried out in 11 healthy young men to investigate the pharmacokinetics of chlorpromazine (CPZ) after a bolus intravenous (IV) dose (10 mg) and three single oral doses (25, 50 and 100 mg), with a washout period of two weeks between doses. Plasma levels of CPZ, CPZ N-oxide (CPZNO), CPZ sulfoxide (CPZSO) and both free and conjugated 7-hydroxy-CPZ (7-HOCPZ) were measured by extraction radioimmunoassays. CPZ exhibited multicompartmental pharmacokinetics in most subjects. There was wide between-subject variability in half life (11.05 h), volume of distribution (1215 l), volume of distribution at steady state (642 l) and mean residence time (8.88 h), whereas systemic clearance was somewhat less variable (76.6 l·h−1). All metabolites were present in measurable concentrations in the plasma of 9 of 11 subjects after IV CPZ, whereas free 7-HOCPZ was not detected in the other 2 individuals. With the exception of CPZNO, the biological half lives of the primary metabolites were longer than the half life of CPZ. After oral administration, the percentage of CPZ reaching the systemic circulation intact (F%) was very low (4–38%) and dose dependant. Moreover, both within-subject and between-subject variances were very high. The maximum plasma concentration (Cmax) and area under the plasma concentration versus time curve extrapolated to infinite time (AUC) showed evidence of nonlinearity, whereas half life did not appear to be dose dependant. These data suggest that the high degree of variability in the pharmacokinetics of CPZ is a result of extensive first pass metabolism rather than variation in half life. The mean AUC for the total conjugates of 7-HOCPZ was about two fold higher than that of the parent drug or any other metabolite. This shows that phase II metabolism plays a very significant role in the disposition of CPZ. As a result, the role of CYP2D6 in the 7-hydroxylation of CPZ cannot be fully assessed without taking phase II metabolism into account.
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  • 104
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 45 (1993), S. 585-587 
    ISSN: 1432-1041
    Keywords: Flumazenil ; benzodiazepine ; absorption ; disposition ; elderly volunteers ; pharmacokinetics ; aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In an open design, randomised, two-way cross-over study, a single 2 mg i.v. dose and a single 30 mg oral dose of flumazenil were each administered to a group of healthy young (n=6) and elderly (n=12) volunteers (male: female 2/1). Plasma samples were collected at intervals and intact drug was assayed. Both the IV and oral doses of flumazenil were very well tolerated by both age groups and no severe or unexpected adverse effects were observed. The main complaints were dizziness and headache, mainly after oral dosing, probably due to the higher Cmax and AUC following this route of administration. After 2 mg i. v. the disposition parameters in the two age groups (elderly/young) were very similar: volume of distribution (Vss): 0.88/0.901·kg−1; total body clearance (ClPL): 0.86/0.99 l·min−1; terminal elimination half-life (t1/2β): 1.02/0.91 h. After the 30 mg oral dose the mean Cmax of 87.6 ng·ml−1 (elderly) and 78.4 ng·ml−1 (young) were generally reached within 0.5 to 1 h. In 26% (elderly) and 23% (young), the absolute bioavailability of flumazenil was very similar. It is concluded that the absorption and disposition paramters of flumazenil were not significantly affected by aging.
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  • 105
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 44 (1993), S. 27-33 
    ISSN: 1432-1041
    Keywords: Nicorandil ; vasodilator ; tolerance study ; blood pressure ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the effects of intravenous nicorandil, a mixed arterial and venous vasodilator, in 48 healthy volunteers. Nicorandil (20, 28, 39, 54, 74, 103, 144, or 200 μg·kg−1) or placebo were given over 5 min to subjects supine (16 subjects, 2 doses) or sitting (32 subjects, 1 dose) in a single-blind crossover design. Electro-cardiographic intervals, blood pressure, and heart rate were measured before and for 8 h after dosing. Blood and urine safety laboratory studies were also performed before and after dosing. All intravenous infusions of nicorandil and placebo were well tolerated and there were no clinically important safety concerns. The most frequent adverse event after nicorandil was headache (24 events by 19 subjects), although its occurrence was not strictly dose related. One subject experienced transient symptomatic hypotension (144 μg·kg−1). Mean plasma nicorandil concentrations were dose-related and fell with a half-life of 0.7 to 1.2 h. Systemic clearance and volume of distribution tended to decrease as dose increased. Sitting subjects showed marginally lower (〈20%) systemic clearances and larger values of Cmax and AUC. Nicorandil produced dose-related reductions in blood pressure, with consistent statistically significant differences from placebo after the 144 and 200 μg·kg−1 doses. The falls in blood pressure were greater for diastolic pressure and in this supine position. At 200 μg·kg−1, the mean falls in systolic/diastolic pressures (mm Hg) during the first hour were 10.9/14.7 supine and 6.1/9.1 sitting; systolic pressure returned to baseline after 8 h and diastolic pressure after 4 h. Heart rate increased transiently (mean peak increase of 17–24 bpm at the end of the 144 and 200 μg·kg−1 infusions). Blood pressure and heart rate changes over time were statistically significantly correlated with plasma nicorandil concentrations. Individual areas under the blood pressure and heart rate change curves likewise correlated with plasma concentration curve areas.
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  • 106
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 44 (1993), S. S31 
    ISSN: 1432-1041
    Keywords: Cefmenoxime ; Renal failure ; continuous haemofiltration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The elimination of cefmenoxime after single and repeated i. v. dosing was studied in 12 patients with severe renal failure and sepsis during continuous haemofiltration. More than 30 % of the drug was found in the filtrate. The sieving coefficient (S) was 0.54. Vss % was unchanged 0.311 · kg−1 in comparison with patients with normal renal function, whereas the mean t/12ß was prolonged to about 16 h, and total clearance was reduced 20.8 ml · min−1 · 1.73 m−2. Once daily administration of 1 g cefmenoxime is suggested as the appropriate dose under such circumstances.
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  • 107
    ISSN: 1432-1041
    Keywords: Oxprenolol ; β-adrenoceptor blockade ; circadian rhythm ; haemodynamics ; pharmacokinetics ; exercise ; healthy volunteers ; kinetic-dynamic model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the effect of dosage time of oxprenolol (Trasicor®) on its pharmacokinetics and pharmacodynamics in six healthy volunteers. The drug effects measured were heart rate and systolic blood pressure during exercise. Oxprenolol was taken orally at 08.00 h, 14.00 h, 20.00 h, and 02.00 h in randomized order, with 1 week between successive doses. There were differences in the pharmacokinetics of oxprenolol for the ratio between the apparent volume of distribution and systemic availability (P=0.04) and for elimination half-life (P=0.006). Both were lowest after administration at 14.00 h (163 (77) l and 1.2 (0.6) h; mean (SD)) and highest after administration at 02.00 h (229 (100) l, and 1.7 (0.6) h). The systolic blood pressure during exercise before oxprenolol did not vary with dosage time, but heart rate during exercise before intake was lowest before dosage time 08.00 h and highest before dosage time 20.00 h (P=0.03). The time-course of heart rate during exercise after oxprenolol was described by a model that incorporated the factors drug concentration and spontaneous diurnal variation. EC50 and Emax did not vary between dosage times. The spontaneous diurnal variation in heart rate during exercise was unaffected by oxprenolol, leading to an apparently greater effect of oxprenolol during the night than during the day.
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  • 108
    Electronic Resource
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    Springer
    European journal of clinical pharmacology 44 (1993), S. S53 
    ISSN: 1432-1041
    Keywords: Quinapril ; Renal failure ; quinaprilat ; haemodialysis ; ACE inhibitor ; pharmacokinetics ; pharmacodynamics ; peritoneal dialysis ; adverse effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and pharmacodynamics of the ACE inhibitor quinaprilat have been studied in six chronic haemodialysis (HD) patients and in six patients undergoing continuous ambulatory peritoneal dialysis (CAPD) after a single oral dose of 2.5 mg quinapril. Mean tmax and Cmax values (SEM) for quinaprilat in interdialytic HD patients were 4.0 (0) h and 84 (8.4) ng · ml−1 respectively, and they did not differ significantly from those in CAPD patients (4.7 (0.7) h and 64 (5.7) ng · ml−1). Elimination half lives were 30 (10.1) h (HD) and 34 (7.3) h (CAPD). Cmax, tmax, t/12, and AUC were increased and CL was decreased compared to data reported previously after giving 2.5 mg to healthy subjects. Peritoneal clearance was calculated as 0.1 (0.1) ml · min−1, thus less than 0.5 % of the dose were removed within 24 h by CAPD. ACE activity was suppressed by more than 93 % between 4 and 24 h postdose (P 〈 0.001). It decreased in both groups with increasing plasma quinaprilat levels. Angiotensin II concentration compared to baseline was significantly decreased at 4 hours (−30.4±10 %) and 24 h (−30±9.9 %) (P 〈 0.05,n=11), while active plasma renin concentration was still significantly increased at 48 h postdose (+60.2±14.5 %,P 〈 0.01). Mean arterial pressure 24 h postdose was significantly (P 〈 0.05) decreased in HD (−12 mm Hg) and CAPD patients (− 20 mm Hg). Only two patients reported unwanted effects (fatigue, dizziness, nausea, and weakness). In conclusion, due to its long lasting effect on ACE activity and on blood pressure in terminal renal failure a starting dose of quinapril 2.5 mg o. d. may be used in hypertensive HD and CAPD patients.
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  • 109
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 44 (1993), S. 361-364 
    ISSN: 1432-1041
    Keywords: Tulobuterol ; β2-adrenoceptor agonist ; aerosol inhalation ; transdermal delivery ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the pharmacokinetics of tulobuterol given transdermally or by aerosol inhalation in healthy male volunteers. Tulobuterol was rapidly absorbed after inhalation, with a tmax of 0.8–1.5 h. The Cmax and the AUC increased linearly with dose. Tulobuterol was well absorbed after transdermal administration, with an absorption lag-time of about 4 h. The Cmax and AUC increased linearly with dose and the tmax was about 9–12 h. The mean percentage of drug absorbed during the application of a patch for 24 h was 82–90% after a single dose and 82–85% during repeated dosing. The mean urinary recoveries as unchanged drug after a single inhalation and patch application were 3–4% and 5–6% respectively. Tulobuterol did not accumulate during repeated inhalation or transdermal application. It was well tolerated, except for an increase in heart rate of 10–20 beats · min−1 after five repeated applications of a 4 mg patch.
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  • 110
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    European journal of clinical pharmacology 44 (1993), S. 387-389 
    ISSN: 1432-1041
    Keywords: Flosequinan ; Congestive heart failure ; elderly ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have investigated the pharmacokinetics of the direct vasodilator flosequinan in elderly patients with congestive heart failure. Eight patients received a single dose of 50 mg, and 8 patients received once-daily treatment with 25 mg for two weeks. In the single dose study, the tmax of flosequinan was 2.5 h, Cmax was 1.17 μg · ml−1 and t1/2 was 5.63 h. The tmax of the metabolite BTS 53554 was 20.3 h, Cmax was 1.44 μg · ml−1 and t1/2 was 62.0 h. BTS 53554 accumulated gradually in the 14-day repeated dose study and steady-state was reached after approximately 2 weeks. Flosequinan was not found to accumulate. Adverse reactions were not observed in either the single or repeated dose study. It is advisable to consider renal function and body weight when flosequinan is to be administered to elderly patients with congestive heart failure. The initial dose should be 25 mg.
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  • 111
    ISSN: 1432-1041
    Keywords: Metoprolol ; controlled-release formulation ; hydrochlorothiazide ; pharmacokinetics ; pharmacodynamics ; healthy volunteers ; efficacy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied a controlled-release formulation containing metoprolol 100 mg and hydrochlorothiazide 12.5 mg. We compared the pharmacokinetics of both substances and the pharmacodynamics of metoprolol with those of a conventional combination tablet. The controlled-release formulation gave less variable plasma metoprolol concentrations, Cmax 138 nmol·l−1 and Cmin 74 nmol·l−1, whereas for the conventional formulation the mean Cmax of metoprolol was 629 nmol·l−1 and the Cmin 20 nmol·l−1. Despite lower relative systemic availability (68%) for metoprolol from the controlled-release formulation and a smaller AUC, metoprolol from the controlled-release formulation produced a greater total effect, calculated as the area under the curve of the effect on exercise heart rate vs. time (303 vs. 259%·h; P〈0.05). Hydrochlorothiazide was rapidly absorbed from both formulations and the plasma concentration profiles were almost superimposable. Controlled-release metoprolol with hydrochlorothiazide combines effective β1-adrenoceptor blockade for 24 h without affecting the pharmacokinetics of hydrochlorothiazide.
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  • 112
    ISSN: 1432-1041
    Keywords: Thiamin ; thiamin monophosphate ; thiamin diphosphate ; distribution ; thiamin elimination ; bioavailability ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The concentrations of thiamin and thiamin monophosphate and diphosphate in plasma and whole blood samples were assessed in six healthy subjects for 12 h and in urine for 24 h following an IV and PO bolus dose of 50 mg thiamin HCl. Unphosphorylated thiamin increased rapidly in plasma after IV administration and then decreased to its initial value within 12 h in all but one subject; the half-life was 96 min. Thiamin mono and -diphosphate increased moderately (56%), and decreased slowly; the half-life of diphosphate was 664 min. Within 24 h, 53% of the administered dose was recovered in the urine, indicating a restricted distribution. After oral administration, the peak thiamin concentration in plasma was reached after 53 min and the concentration then had increased to 179% of its initial value. The elimination half-life was 154 min, and only 2.5% of the given dose was recovered in the urine. The relative bioavailability of thiamin was 5.3%. A moderate amount of the administered thiamin was stored in blood. Other body tissues must play an important part, therefore, in the distribution of thiamin.
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  • 113
    ISSN: 1432-1041
    Keywords: Theophylline ; Antacids ; Asthma ; slow-release formulations ; pharmacokinetics ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Antacids can modify the pharmacokinetic parameters of sustained-release preparations of theophylline by changing the gastric pH. Though this has been studied with various theophylline/antacid combinations, the specific preparations investigated here have not previously been tested. The objective of the study was to assess any change in the availability of theophylline from a sustained-release preparation (SR), induced by the coadministration with an antacid. The study was designed as a double-blind randomized crossover trial in the Pneumology Departments of three general hospitals. Fifteen patients were studied. They all had stable asthma treated with theophylline and no major organ failure or gastro-intestinal lesions requiring the use of antacids. The antacide (aluminium hydroxide 800 mg and magnesium hydroxide 800 mg), or placebo, tid, was added to a stable regimen of theophylline SR bid, for 4 days, in crossover fashion. Plasma theophylline concentrations were measured before and 1,2,3,4,6,8,10,12,16 and 24 h after the morning dose of Armophylline on the fourth day of each treatment period; the maximum plasma concentration (Cmax), and time to Cmax (tmax) were noted, and the area under the 24-h time-concentration curve (AUC0–24) and mean plasma concentration (Cmean) were computed. Peak expiratory flows on the same day, before and 3, 6 and 12 h after the morning dose of Armophylline were also measured. There was no change in any of the parameters studied. The addition of the antacide to theophylline, each given according to standard clinical practice, did not modify the pharmacokinetics of the latter. This result probably can not be generalized to all pairs of sustained-release theophylline-antacid preparations.
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  • 114
    ISSN: 1432-1041
    Keywords: Prednisolone ; Rifampin ; drug-interaction ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have investigated changes in the pharmacokinetics of prednisolone caused by co-administration or discontinuation of rifampin. Serial IV pharmacokinetic studies of prednisolone (1 mg/kg) in groups of 3 patients over a 1 month period of rifampin co-treatment or after its withdrawal, revealed significant changes in the area under the curve, the total clearance, the non-renal clearance and the half-life. The changes in the pharmacokinetic parameters reached a 1.5 to 2-fold plateau after 2 weeks and the half maximal effect was attained within 5 days. Neither the volume of distribution nor the protein binding of prednisolone were significantly altered.
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  • 115
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    European journal of clinical pharmacology 44 (1993), S. 279-282 
    ISSN: 1432-1041
    Keywords: Nifedipine ; Doxazosin ; combination ; pharmacokinetics ; liver blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a single-blind study 12 normotensive men took nifedipine 20 mg (Group 1, n=6) or doxazosin 2 mg (Group 2, n=6), followed by the combination. Each subject attended on four 9-h study days for evaluation of the effects of single and multiple doses of the monotherapy and the effects of adding single and multiple doses of the second drug. Measurements of BP, HR, plasma drug concentrations, and apparent liver blood flow were recorded. The combination was generally well tolerated. BP was consistently lower with the combination than with either monotherapy: for example, average erect BP was 108/61 (Group 1) and 112/62 mmHg (Group 2) compared with 122/66 and 116/68 during steady-state monotherapy. The introduction of nifedipine in Group 2 was associated with a significant increase in liver blood flow at 1.5 h: 1560 vs 1050 ml · min−1 during monotherapy with doxazosin. There was no significant kinetic interaction. In particular, the steady-state AUC of doxazosin was unaffected by the addition of nifedipine: 257, 307, 301, and 256 ng · ml−1 · h for the 4 study days (Group 2).
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  • 116
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    European journal of clinical pharmacology 45 (1993), S. 383-385 
    ISSN: 1432-1041
    Keywords: Chloroquine ; Desethylchloroquine ; Blood levels ; Steady state concentrations ; pharmacokinetics ; rheumatic diseases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a review of studies using appropriate methods for drug determinations and controlled intake, an interindividual variation in chloroquine concentrations of 2.3 to 5.6-fold was found. In our department, steady-state concentrations were evaluated in 40 patients with rheumatic diseases. The variation in whole blood concentrations was 11-fold for chloroquine and 10-fold for the desethylchloroquine metabolite. The mean ratio between desethylchloroquine and chloroquine concentrations was 0.53 and the Spearman-Rank correlation 0.92. The correlation between age and the ratio of chloroquine concentration/dose was 0.36 (P〈0.05) and the corresponding correlation for body weight was −0.43 (P〈0.05). Our data indicate that body weight and age are important independent factors for the disposition of chloroquine. However, when extensive 100-fold variations in concentrations are found between individuals we suggest that the reliability of the dose intake should be questioned.
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  • 117
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    European journal of clinical pharmacology 45 (1993), S. 387-388 
    ISSN: 1432-1041
    Keywords: Iron deficiency anaemia ; Phenytoin ; bioavailability ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Iron deficiency is a common nutritional deficiency, which leads to structural functional and enzymatic changes in the body that may affect the pharmacokinetics of drugs. The present study in 7 normal volunteers and 8 adult male patients with irondeficiency anaemia (IDA) was done to investigate the effect of iron deficiency and its treatment with total dose iron (TDI) on the bioavailability of a single dose of phenytoin. Phenytoin bioavailability was investigated before and 3 and 28 days after TDI. The bioavailability parameters Cmax, tmax, AUC and 2 h phenytoin concentrations were not significantly different in anaemic patients as compared to normal volunteers before or after treatment, except for an increase in tmax 28 days after TDI treatment.
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  • 118
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    European journal of clinical pharmacology 45 (1993), S. 377-381 
    ISSN: 1432-1041
    Keywords: Midazolam ; Ephedrine ; Sauna ; pharmacokinetics ; pharmacodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of a sauna on the pharmacokinetics and pharmacodynamics of single doses of ephedrine 50 mg and midazolam 15 mg have been studied in 6 young healthy women in a placebo-controlled, double-blind study. The sauna (3 × 10 min; temperature 80–100°C; relative humidity 30–50%) modified the pharmacokinetics of both drugs: it retarded the absorption of midazolam estimated as Ka values, and it reduced the mean plasma midazolam concentrations at 2 h; ephedrine, was absorbed more rapidly and the maximum plasma concentration occurred earlier than in the control sessions. Changes in the pharmacodynamics due to the sauna were consistent with the pharmacokinetic findings: midazolam decreased flicker recognition and induced exophoria significantly less during the early sauna period than in the control session, whereas ephedrine made the volunteers subjectively more alert at that time. Later, at 2.5 and 3.5 h (1 h 20 min and 2 h 20 min after cessation of the sauna), and despite the equalisation of the plasma levels, midazolam caused significantly more exophoria after the sauna than in the control situation. This indicates an influence of a sauna on drug pharmacodynamics in the post-sauna adaptive phase. The results suggest that exposure to a sauna may alter both drug pharmacokinetics and pharmacodynamics.
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  • 119
    ISSN: 1432-1041
    Keywords: Metoclopramide ; Biliary excretion ; enterohepatic recirculation ; Nasobiliary drainages ; pharmacokinetics ; biliary obstruction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The biliary excretion and apparent oral clearance of metoclopramide (MCL) were determined after oral administration of 1 mg MCL/kg body weight to 10 patients suffering from extrahepatic cholestasis with nasobiliary tube for drainage of the common bile duct. A bilioduodenal endoprosthesis was subsequently fitted in 6 of these patients, i.e. the enterohepatic circulation was restored, and the apparent oral clearance was re-determined. Biliary excretion, comprising free MCL and the products of conjugation, accounted for less than 1% of the administered dose. In accordance with this, the median areas under the plasma concentration-time-curves AUC(0–15 h) in patients with intact and interrupted enterohepatic recirculation were of similar size. The pharmacokinetic values in patients with cholestasis (median apparent oral clearance 0.5 l·kg−1·h−1; median t1/2 4.5 h) were similar to those previously reported in patients with healthy liver function. We conclude that it is not necessary to adjust single doses of MCL in patients recovering from obstructive jaundice.
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  • 120
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    European journal of clinical pharmacology 45 (1993), S. 425-430 
    ISSN: 1432-1041
    Keywords: Amlodipine ; Felodipine ER ; pharmacokinetics ; blood pressure response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary This study investigated potential therapeutic differences between Amlodipine 5 mg and Felodipine ER 10 mg in 12 normotensive/borderline hypertensive subjects by comparison of the plasma drug concentration-time profiles and the blood pressure and heart rate responses. There was significantly less trough-to-peak variability in plasma drug concentrations with amlodipine with a ratio of 67%, compared to 37% for felodipine. Correspondingly there was less variability with amlodipine in the blood pressure reductions across the dosage interval. Overall, amlodipine displayed a more consistent hypotensive effect across 24 hours and lower blood pressure values at trough, i. e. 24 hours post-dose.
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  • 121
    ISSN: 1432-1041
    Keywords: Didanosine ; Metoclopramide ; Loperamide ; HIV patients ; pharmacokinetics ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of orally-administered didanosine were evaluated in 6 male and 6 female HIV seropositive patients to determine the effect of pretreatment with metoclopramide, an inducer of gastrointestinal motility, and loperamide, which retards motility. Using a randomized, balanced, crossover design, each patient received the following three treatments under fasting conditions: didanosine as a single agent, didanosine 5 min after a single 10 mg intravenous dose of metoclopramide, and didanosine 1 h after the final of 4 doses, 4 mg each, of loperamide. Serial blood and urine samples were collected for up to 12 h after each dose. Plasma and urine aliquots were analysed for intact didanosine using HPLC with UV detection. Pharmacokinetic parameter values were calculated using noncompartmental methods. The mean Cmax values were significantly greater for the didanosine single agent (2.04 μg·ml−1) and didanosine with metoclopramide (2.30 μg·ml−1) treatments than for the combination of didanosine with loperamide (1.57 μg·ml−1). The t1/2 in males was significantly greater than in females for the didanosine (1.75 vs 1.12 h, respectively) and didanosine with metoclopramide treatments (1.74 vs 1.20 h, respectively). No significant treatment or gender effects were observed for AUC or UR (urinary recovery). The pharmacokinetics of didanosine were not altered appreciably by dosing with metoclopramide. Administration with loperamide affected the rate but not the extent of absorption. There were no clinically relevant differences between males and females in the disposition of didanosine.
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  • 122
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    European journal of clinical pharmacology 45 (1993), S. 431-436 
    ISSN: 1432-1041
    Keywords: Fosinopril ; ACE inhibitors ; haemodialysis ; pharmacokinetics ; pharmacokinetics-pharmacodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and pharmacodynamics of fosinoprilat, the diacid of fosinopril sodium (a new angiotensin-converting enzyme (ACE) inhibitor), were investigated in six haemodialysis patients. Intravenous 14C-fosinoprilat (7.5 mg), oral 14C-fosinopril sodium (10 mg) and oral fosinopril sodium (10 mg) were administered in an open-label, randomized study. Mean maximum concentration (Cmax), clearance (CL), volume of distribution at steady-state (Vss), mean residence time (MRTiv), and t1/2 values after IV administration of 14C-fosinoprilat were 2,042 μg·ml−1, 11.3 ml·min−1, 11.01, 16.3 h and 28.3 h, respectively. Following oral administration of 14C-fosinopril, mean Cmax, time to maximum plasma concentration (tmax), and fosinoprilat bioavailability values were 197 ng·ml−1, 5.2 h and 29.2 %. Para-hydroxy fosinoprilat and fosinoprilat glucuronide comprised approximately 15 % and 2 % of radioactivity recovered in faeces. Four hours of haemodialysis only cleared approximately 1.5 % of the administered dose. The maximum effect (Emax) model was fitted to the percentage inhibition of serum ACE activity vs. fosinoprilat concentration data in three patients. Emax ranged from 95.3 to 102.5 %, and IC50 (the fosinoprilat concentration required to produce 50 % of Emax) ranged from 2.6 to 4.2 ng·ml−1. Pharmacokinetic variables of the patients were similar to those in patients with moderate to severe renal dysfunction. Dosage modifications or supplemental dosing following dialysis are unnecessary.
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  • 123
    ISSN: 1432-1041
    Keywords: Nicorandil ; vasodilator ; continuous infusion ; blood pressure ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the pharmacokinetics and haemodynamic effects of nicorandil after a 12-h infusion. Nicorandil is a mixed vasodilator combining the actions of a nitrate and a potassium channel opener. Nicorandil was infused for 12 h in 21 healthy volunteers at rates of 0.05, 0.10, and 0.20 μg·kg−1·min−1 using a placebo controlled, crossover design. Systemic blood pressure, heart rate, electrocardiographic (ECG) intervals, and cardiac output (impedance cardiography) were measured supine and standing. Dose-related, steady-state plasma nicorandil concentrations occurred within 3 to 4 h. Nicorandil's pharmacokinetics were linear with dose. Four 0.20 μg·kg−1·min−1 nicorandil infusions were terminated early primarily because of moderate or severe headaches. There were no safety concerns (ECG intervals, laboratory assays). Blood pressure fell versus placebo only in the standing position and heart rate increased slightly (not significant). That is, standing blood pressure in the 6 to 12 h interval fell from baseline 8.0*/6.8, 1.6/5.1, and 9.8*/7.9* mmHg (systolic/diastolic, *=P〈0.05 versus placebo) at 0.05, 0.10, and 0.20 μg·kg−1·min−1 respectively. Cardiac output increased slightly above placebo at lower doses. Haemodynamic changes correlated poorly with plasma nicorandil concentrations. Similar total doses were less well-tolerated when extended over 12 h. We saw no evidence of pharmacodynamic tolerance to nicorandil within 12 h.
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  • 124
    ISSN: 1432-1041
    Keywords: Piperacillin ; Vancomycin ; liver transplantation ; antibioprophylaxis ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of piperacillin and vancomycin used intravenously as antibioprophylaxis were measured in the plasma and bile during orthotopic liver transplantation. Piperacillin (4 g and then 2 g every 4 h) and vancomycin (1 g and then 0.5 g every 6 h) were infused in 10 patients. During vascular clamping without venovenous bypass, clearance of both antibiotics decreased in relation to renal insufficiency. During the surgical procedure, volume of distribution of both drugs increased because of fluid redistribution. The peaks of piperacillin after first, second and third administrations were respectively 314, 265 and 210 mg·l−1, while trough levels were 46.5, 55.2 and 54.5 mg·l−1. The peaks of vancomycin were 54.4, 49.6 and 40.9 mg·l−1, while first and second trough levels were 9.5 and 12 mg·l−1. These plasma concentrations were quite similar to levels reported in healthy subjects despite large blood loss and fluid replacement. However, piperacillin trough concentrations (〈64 mg/l) were too low in relation to its concentration-dependent antibacterial activity and vancomycin peak concentrations (≥40 mg/l) were slightly too high in relation to its toxicity.
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  • 125
    ISSN: 1432-1041
    Keywords: Piroxicam ; H2 receptor antagonists ; Arthritis ; drug interaction ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A randomised crossover study was performed in subjects with rheumatoid arthritis (or other arthropathies) to investigate if any alteration in the steady pharmacokinetics of the NSAID piroxicam (a drug which is extensively metabolised via cytochrome P450) or its major metabolites occurred as a result of coadministering either cimetidine or nizatidine. Twelve females and 2 males with mean age, weight, and albumin concentrations of 58 years, 61 kg, and 40 g·L−1 respectively, completed the study. Comparisons were made between the following parameters: plasma piroxicam AUCs [AUC0-24(P)], plasma 5-hydroxypiroxicam AUCs [AUC0-24(5-OHP)], the ratio of these i.e. AUC0-24(5-OHP):AUC0-24(p), the % piroxicam daily dose excreted in urine as 5-hydroxypiroxicam (before and after glucuronidase incubation); and the mean of the steady state trough piroxicam, and 5-hydroxypiroxicam concentrations (obtained during each study phase in addition to the wash-out period). A statistically significant difference as a result of initiating either cimetidine or nizatidine was obtained only for the ratio AUC0-23(5-OHP):AUC0-24(P). This was indicative of a weak potential to inhibit piroxicam hydroxylation. No clinically significant alteration in the steady state pharmacokinetics of piroxicam occurred in these subjects as a result of cimetidine or nizatidine coadministration. Consequently it is unlikely that any adverse events would arise from these combinations.
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  • 126
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    European journal of clinical pharmacology 44 (1993), S. 501-503 
    ISSN: 1432-1041
    Keywords: Zidovudine ; Diarrhoea ; HIV ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Many patients with AIDS have gastrointestinal complaints, including the major clinical disorder of chronic diarrhoea. The pharmacokinetics of zidovudine was studied in 9 male patients with HIV infection and diarrhoea to establish whether drug absorption was impaired in them. The peak plasma concentration and AUC after a single oral dose of 200 mg, were the same as those reported in 6 healthy male volunteers (3.1 vs 4.0 μmol·l−1 and 7.2 vs 5.2 μmol·h·l−1, respectively). Since the bioavailability of zidovudine is not particularly impaired, oral zidovudine therapy can be maintained in patients with diarrhoea.
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  • 127
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    European journal of clinical pharmacology 44 (1993), S. 497-500 
    ISSN: 1432-1041
    Keywords: Nocloprost ; PGE2-analoga ; clearance ; half life ; absolute bioavailability ; pharmacokinetics ; i. v. dose ; oral dose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and absolute bioavailability of nocloprost, a synthetic PGE2-analogue with cytoprotective properties, was investigated in human volunteers as a function of the dose. Ten young male volunteers received nocloprost 5 μg i. v. and 100, 200 and 400 μg p.o. in random order at weekly intervals. Serum nocloprost levels were monitored for up to 12 h after each dose, using a specific, validated assay. After nocloprost 5 μg i. v. the highest serum level of 373 pg·ml−1 was found in the first sample 5 min after injection, and the subsequent decline showed one or two phases, with half-lives of 4 and 49 min. The AUC was 89 pg·h·ml−1, the total plasma clearance was 13.2 ml·min−1·kg−1, and the volume of distribution at steady state was 0.16 l·kg−1. After oral administration the maximum serum level and AUC increased in proportion to the dose. tmax showed a wide scatter, with an average value of about 30 min independent of the dose. Although not detectable in every subject, post maximum serum levels declined biphasically, with half-lives of ca 10 and 35–40 min. The absolute bioavailability after oral administration averaged about 2% and was independent of the dose.
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  • 128
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    European journal of clinical pharmacology 44 (1993), S. 505-507 
    ISSN: 1432-1041
    Keywords: Adenosine ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma kinetics of adenosine was investigated in healthy volunteers after a 1 minute infusion of 2.5, 5 and 10 mg (38, 79 and 148 μg·kg−1 respectively) and after infusion of 200 μg·kg−1 in 10 min followed by 400 μg·kg−1 in 10 min. As the dose in the 1 min infusion study was increased the mean CL of adenosine decreased (10.7, 4.70 and 4.14 l·min−1, respectively), its mean half-life increased (0.91, 1.24 and 1.86 min, respectively), and the mean volume of distribution did not show any clear trend (8–13 l). After the 20 minute infusion the plasma level of adenosine reached a peak value comparable to that observed after infusion of 5 mg in 1 min (about 0.5 μg·ml−1), but the mean clearance and half-life were significantly different (12.1 l·min−1 and 0.63 min respectively). In all the subjects the plasma concentration of adenosine had returned to the baseline value in 5–15 min after the end of the infusion.
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  • 129
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    European journal of clinical pharmacology 44 (1993), S. 575-578 
    ISSN: 1432-1041
    Keywords: Pantoprazole ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma pharmacokinetics of pantoprazole have been investigated following single intravenous infusion and single oral administration at a dose of 40 mg to 12 healthy male subjects in a randomised cross-over study. Both treatments were generally well tolerated and no relevant compound-related adverse events were noted. The plasma pharmacokinetics of pantoprazole following intravenous infusion in this group of subjects were characterised by a total plasma clearance of 0.13 l·h−1·kg−1 and apparent terminal elimination half-life 1.9 h. The apparent volume of distribution estimated at steady state (0.171·kg−1) was compatible with the localization of a major fraction of the compound in extracellular water. Following oral administration as an enteric-coated tablet formulation, a variable onset of absorption was followed by rapid attainment of maximum plasma concentrations of pantoprazole. Pantoprazole was well absorbed following oral administration; the absolute systemic bioavailability of the compound was estimated as 77% (95% CI, 67 to 89%).
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  • 130
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    European journal of clinical pharmacology 44 (1993), S. 563-568 
    ISSN: 1432-1041
    Keywords: Oestradiol analogues ; 17β-oestradiol ; oestrone ; oestriol ; micronised oestradiol ; oestradiol cyclo-octylacetate ; oestradiol decanoate ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A randomised, single-blind comparative study was carried out in 9 ovariectomized women to evaluate the kinetics of single doses of three different steroid combinations: 0.150 mg desogestrel +2.0 mg micronized 17β-oestradiol, 0.150 mg desogestrel +0.500 mg 17β-oestradiol cyclo-octyl acetate and 0.150 mg desogestrel +1.0 mg 17β-oestradiol decanoate. Serum levels of 17β-oestradiol and oestrone were measured, as well as the excretion of 17β-oestradiol and its metabolites (oestrone and oestriol) in urine. In relation to the doses given, higher peak serum concentrations of 17β-oestradiol were obtained after the two fat soluble analogues, while the AUCs were similar to that after micronised 17β-oestradiol. However, there was more extensive conversion of the micronised 17β-oestradiol preparation into oestrone compared to 17β-oestradiol cyclo-octyl acetate and 17β-oestradiol decanoate. The oestrone/17β-oestradiol serum concentration ratio was approximately 2.6 before tablet intake and remained essentially unchanged after intake of 17β-oestradiol cyclo-octyl acetate and 17β-oestradiol decanoate. After micronized 17β-oestradiol however, there was a 2–3-fold increase in the ratio at Cmax and slower elimination of 17β-oestradiol from plasma, which may be due to the fact that high serum oestrone levels may serve as a reservoir, since both a metabolite and also a precursor of 17β-oestradiol. The urinary excretion of 17β-oestradiol, oestrone and oestriol was highest after oral administration of micronized 17β-oestradiol compared to 17β-oestradiol cyclo-octyl acetate and 17β-oestradiol decanoate. The time pattern of urinary excretion reflected the serum concentration profiles of the preparations given.
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  • 131
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    European journal of clinical pharmacology 44 (1993), S. 579-582 
    ISSN: 1432-1041
    Keywords: 2-Chloro-2′-deoxyadenosine (CdA) ; omeprazole ; food ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of oral CdA (0.24 mg/kg) was studied in 4 patients (1 with hairy cell leukaemia and 3 with B-cell chronic lymphocytic leukaemia) to determine any effect of food and fasting with and without omeprazole. Food intake did not significantly influence the bioavailability of CdA (42% after food intake vs 46% while fasting) but it did reduce the maximum plasma concentration (Cmax) by 40%; 83 compared to 116 nM while fasting. The time to reach maximum concentration (tmax) was delayed about 0.8 h after food intake. Pretreatment with omeprazole did not significantly influence the bioavailability of CdA (51% vs 46% without), or the interindividual variability in bioavailability in the fasting state (C.V. 0.26 with and C.V. 0.27 without). In conclusion, there was a small, though not statistically significant reduction in the bioavailability of CdA after food intake. Omeprazole did not significantly improve the bioavailability of CdA.
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  • 132
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    European journal of clinical pharmacology 44 (1993), S. 583-586 
    ISSN: 1432-1041
    Keywords: Carvedilol ; Drug interaction ; digitoxin ; phenprocoumon ; pharmacokinetic interaction ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The possibility of a pharmacokinetic interaction between carvedilol and digitoxin (Study I) or phenprocoumon (Study II) has been evaluated in groups of 12 healthy volunteers. The bioavailability (Cmax, tmax, AUC) of digitoxin and phenprocoumon were assessed after a single dose, given once alone and once on day 6 of treatment with carvedilol 25 mg o.d. Cmax, tmax, AUC and Ut of carvedilol and desmethylcarvedilol were also investigated after the fifth dose of carvedilol and after the sixth dose given concomitantly with digitoxin or phenprocoumon. In Study I, the 95% confidence intervals of the ratio test versus the reference findings were; digitoxin Cmax 0.80–1.20, tmax 0.56–1.14, AUC 0.97–1.33, and for carvedilol Cmax 0.81–1.22; tmax 0.66–1.23; AUC 0.91–1.17. Formation of the active metabolite desmethylcarvedilol and the urinary recovery of carvedilol and esmethylcarvedilol were not influenced by digitoxin. In Study II Cmax and AUC of phenprocoumon were not changed after carvedilol. Cmax of carvedilol was decreased after phenprocoumon. The kinetic parameters of phenprocoumon were Cmax 0.80–1.05, tmax 0.47–2.00, AUC 0.78–1.05, and for carvedilol Cmax 0.59–1.06, tmax 0.71–1.73; AUC 0.80–1.08, respectively. The plasma levels of desmethylcarvedilol and the urinary recovery of carvedilol and desmethylcarvedilol were not influenced by phenprocoumon. The blood pressure and heart rate after carvedilol alone were not affected by concomitant administration of digitoxin or phenprocoumon.
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  • 133
    ISSN: 1432-1041
    Keywords: Amitriptyline ; Toloxatone ; Depression ; pharmacokinetics ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The possibility of a pharmacokinetic interaction between amitriptyline and toloxatone (a new MAOI-A) has been studied in 17 depressed in-patients. Amitriptyline and its demethylated and hydroxylated metabolites in blood and urine were measured at steady state after the administration of amitriptyline with and without toloxatone in steady state. The metabolic status of patients was determined using the dextromethorphan phenotyping test. There was only a minor pharmacokinetic interaction between amitriptyline (AMT) and toloxatone, with a small increase in the AMT/NT (nortriptyline) plasma ratio: 0.68 before and 0.78 after toloxatone. The urinary excretion and plasma levels of AMT and its metabolites were not affected by the co-therapy. Three of the patients were poor metabolisers, but this did not predict the magnitude of the drug interaction. The interaction does not justify plasma level monitoring of amitriptyline as the change in pharmacokinetics was so small.
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  • 134
    ISSN: 1432-1041
    Keywords: Felodipine ; Nitrendipine ; Nifedipine ; pharmacokinetics ; stereoselectivity ; enantiomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of racemic (rac) felodipine, rac-nitrendipine and nifedipine (all given as an oral dose of 20 mg in solution) have been investigated in a randomised cross-over study in 12 healthy male subjects using stereoselective assays. Both felodipine and nitrendipine exhibited stereoselective pharmacokinetics. On average, the AUCs of the active (S)-enantiomers of felodipine and nitrendipine were 139% and 104% higher than those of their optical antipodes, but the elimination half-lives of the enantiomers of each racemate were not different. The AUCs of nifedipine, rac-felodipine, rac-nitrendipine and of their enantiomers were highly correlated (all r〉0.83), suggesting closely related rate limiting steps in the in vivo first-pass metabolism of these high-clearance drugs. Stereoselectivity was only a minor contributor to inter-individual variability in the oral pharmacokinetics of these compounds in healthy subjects.
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  • 135
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    European journal of clinical pharmacology 44 (1993), S. 183-187 
    ISSN: 1432-1041
    Keywords: Perindopril ; Haemodialysis ; angiotensin-converting enzyme inhibitors ; perindoprilat ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the pharmacokinetics of perindoprilat, the active metabolite of perindopril, in 7 hypertensive patients undergoing haemodialysis after short-term and long-term (1 month) perindopril. We also measured angiotensin-converting enzyme activity. Each subject took 2 mg of perindopril after a 4-hour haemodialysis. Serial blood samples were obtained each hour during dialysis and between dialysis (7 samples over 44 h). Perindoprilat steady state was reached within 5 haemodialysis sessions. There was a high degree of angiotensin converting enzyme inhibition after the first dose. Administration for 1 month did not modify the time to peak perindoprilat concentration but significantly increased the mean maximal concentration: 10.2 versus 26.8 ng · ml−1. The mean accumulation ratio was 3.5. The mean reduction in perindoprilat concentration after dialysis was greater than 50%. Perindoprilat haemodialysis clearance was 62 ml · min−1 after the first administration and 72 ml · min−1 after 1 month. Tolerance of perindopril was good throughout the study. Treatment can be begun with 2 mg of perindopril after haemodialysis in hypertensive patients undergoing haemodialysis.
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  • 136
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    European journal of clinical pharmacology 44 (1993), S. 225-230 
    ISSN: 1432-1041
    Keywords: Nicotine ; subcutaneous ; pharmacokinetics ; stable isotopes ; deuterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The stable isotope-labeled compound 3',-3'-dideuteronicotine (nicotine-d2) was used to investigate the disposition kinetics and effects of nicotine administered subcutaneously to 6 smokers. Plasma nicotine-d2 concentrations were measured for 8 h after subcutaneous injection of 4 doses (0.4, 0.8, 1.2, and 2.4 mg). Peak plasma nicotine concentration correlated well with the dose, averaging 2.8 to 14.8 ng/ml, 19 to 25 min after injection of the 0.4 mg and 2.4 mg doses, respectively. The plasma clearance over bioavailability ratio (CL/f) averaged 12 to 13 ml · min−1 · kg−1, similar to the clearance reported previously for intravenously administered nicotine. Thus, bioavailability appears to be approximately 100%. The heart rate response was more sensitive to the nicotine dose than the blood pressure response. Subjective effects showed large interindividual variability. The results reported herein may be useful in planning future studies. Administration of nicotine by the subcutaneous route appears to be a practical and safe method for studying the human pharmacology of nicotine.
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  • 137
    ISSN: 1432-1041
    Keywords: Terfenadine metabolism ; cimetidine ; ranitidine ; antihistamines ; Torsades de Pointes ; pharmacokinetics ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Terfenadine is a widely prescribed non-sedating antihistamine which undergoes rapid and almost complete first pass biotransformation to an active carboxylic acid metabolite. It is unusual to find unmetabolised terfenadine in the plasma of patients taking the drug. Terfenadine in vitro is a potent blocker of the myocardial potassium channel. Overdose, hepatic compromise and the coadministration of ketoconazole and erythromycin result in the accumulation of terfenadine, which is thought to be responsible of QT prolongation and Torsades de Pointes ventricular arrhythmia in susceptible individuals. Cimetidine and ranitidine are two popular H2 antagonists which are often taken with terfenadine. The effects of cimetidine and ranitidine on terfenadine metabolism were studied in two cohorts of 6 normal volunteers given the recommended dose of terfenadine (60 mg every 12 h) for 1 week prior to initiation of cimetidine 600 mg every 12 h or ranitidine 150 mg every 12 h. Pharmacokinetic profiles and morning pre-dose electrocardiograms were obtained whilst the patients were on terfenadine alone and after the addition of cimetidine or rantidine. One of the subjects in each cohort had a detectable plasma level of parent compound after 1 week of terfenadine therapy alone; it did not accumulate further after addition of the H2 antagonist. The pharmacokinetics of the carboxylic acid metabolite of terfenadine (Cmax, tmax, AUC) were not significantly changed after co-administration of either H2 antagonist. None of the remaining 5 subjects in either cohort demonstrated accumulation of unmetabolised terfenadine after addition of the respective H2 antagonist and electrocardiographic QT intervals and T-U morphology in them was not changed during the course of the study. We conclude that cimetidine and ranitidine in the dosages used in this study did not affect the metabolism of terfenadine, and that patients exposed to these drug combinations are not at increased risk of altered cardiac repolarisation.
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  • 138
    ISSN: 1432-1041
    Keywords: Batanopride ; Renal disease ; metabolites ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the disposition of batanopride and its three major metabolites (the erythro-alcohol, threo-alcohol, and N-desethyl metabolites) in 27 subjects with various degrees of renal function after intravenous infusion of a single dose of 3.6·mg·kg−1 of batanopride over 15 min. The subjects were assigned to one of three treatment groups: group 1, normal renal function (creatinine clearance ≥75 ml·min−1·1.73 m−2; n=13); group 2, moderate renal impairment (creatinine clearance 30–60 ml·min−1·1.73 m−2; n=8); group 3, severe renal impairment (creatinine clearance ≤30 ml·min−1·1.73 m−2; n=6). The terminal half-life of batanopride was significantly prolonged from 2.7 h in group 1 to 9.9 h in group 3. The renal clearance of batanopride was significantly lower in group 3 (25 ml·min−1) compared with group 1 (132 ml·min−1). There were no differences in plasma protein binding or steady-state volume of distribution of batanopride among the groups. There were significantly lower renal clearances for all three metabolites in groups 2 and 3 compared with group 1. The half-lives of all three metabolites were significantly prolonged in group 3 compared with group 1. The dose of batanopride may need to be reduced in patients with creatinine clearances less than 30 ml·min−1·1.73 m−2 to prevent drug accumulation and avoid possible dose-related adverse effects.
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  • 139
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    European journal of clinical pharmacology 45 (1993), S. 79-84 
    ISSN: 1432-1041
    Keywords: Tiopronin ; 2-Mercaptopropionylglycine ; bioavailability ; urinary excretion ; cystine urolithiasis ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Ten healthy subjects were given 500 mg (3064 μmol) tiopronin, or 2-mercaptopropionylglycine (2-MPG) by mouth. Cmax was reached after 3–6 h, and after a shorter β-phase a long terminal half-life of 53 h of total tiopronin was found. Tiopronin measured as unbound (non-protein-bound) drug disappeared more rapidly from plasma, with a calculated t 1/2 of 1.8 h. Mean residence time was higher (58 h) when calculated as total tiopronin than as unbound tiopronin (6 h), and this was also the case for the volume of distribution (Vλ=4551 vs Vλ,u=41 1). The results indicate extensive protein binding in plasma and a deep pool of tissue bound tiopronin after the first absorption and distribution phases. Absolute bioavailability (f) was 63%, and bioavailability calculated from urinary excretion was 47%, which are well correlated with each other. Urinary excretion was mainly confined to the first 6 h (74%) and was almost complete (98%) within 12 h. We conclude that the maximal absorption of the tiopronin was late, protein and tissue binding of the drug were high and its bioavailability varied. The renal excretion of low molecular weight tiopronin occurred early, which implies that the drug should be given in divided doses, at least twice daily, for optimal efficiency in the treatment of cystinuria.
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  • 140
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    European journal of clinical pharmacology 45 (1993), S. 89-91 
    ISSN: 1432-1041
    Keywords: Diphemanil methylsulphate ; antimuscarinic agent ; pharmacokinetics ; infants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of diphemanil methylsulphate was evaluated after oral administration of a single 3 mg·kg−1 dose to 5 infants being treated for symptomatic bradycardia. The mean pharmacokinetic parameters of oral diphemanil methylsulphate in infants were similar to those in adults. The mean half-life was 8.6 h. This would allow administration three times a day in infants instead of four to six times a day, as currently prescribed. The mean residence time decreases significantly with age (Spearman's r′=−1), and there is a trend for the half-life to decrease with age (r′=−0.9; NS), suggesting an influence of maturation on its elimination.
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  • 141
    ISSN: 1432-1041
    Keywords: Parkinson's disease ; Levodopa ; intraduodenal infusion ; PLM-test ; video ratings ; plasma level response ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Motor performance of five patients with advanced Parkinson's disease was investigated during their optimum oral therapy (conventional tablets and/or depot capsules) and during a continuous duodenal infusion of levodopa. Due to the low water solubility of the drug, conventional tablets of levodopa + carbidopa (Sinemet®) were milled and dispersed in a 1.8% aqueous methylcellulose solution. The dispersion was delivered nasoduodenally by a portable pump. The effect of levodopa in the two dosing regimens was estimated optico-electronically every 15 min and was also evaluated from videorecordings every 30 min and plasma levels of levodopa was regularly measured. Each dosage regimen the was studied twice, at a 2–4 day interval. Duodenal infusion improved motor function in all five patients and the fluctuations were reduced when compared to the oral therapy. Variation in plasma levodopa concentrations was 3–10 fold during oral therapy, while during the infusion a stable concentration was obtained. The therapeutic concentration varied from 0.3–3 μg ml−1 between patients. The relative bioavailability of levodopa in the solid preparation compared to the dispersion was in all patients 100%. Our results encourage further development of a duodenal infusion system with a levodopa dispersion for clinical use in parkinsonian patients who show severe fluctuation.
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  • 142
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    European journal of clinical pharmacology 45 (1993), S. 135-139 
    ISSN: 1432-1041
    Keywords: Furosemide ; protein binding ; pharmacokinetics ; renal function ; dehydration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have shown that, within therapeutic plasma concentrations, the unbound fraction of furosemide changes in direct proportion to the reciprocal of the plasma albumin concentration (correlation coefficient 0.99). Changes in the albumin concentration were produced by ultrafiltration of human plasma using a haemofiltration filter. Thus, we propose that, when studying changes in the pharmacokinetics of a highly protein bound drug, calculated changes in the unbound fraction offer an alternative to actual measurement of the unbound concentration, which is often difficult. Nine healthy volunteers receiving a continuous furosemide infusion were studied in normovolaemia and after dehydration (−1.4 kg), with and without pretreatment with an angiotensin converting enzyme inhibitor (captopril) or an a1-adrenoceptor blocking agent (prazosin). Significantly larger changes in the renal clearance of furosemide were found that could be explained by changes in the unbound fraction. Following dehydration, the unbound fraction of furosemide was decreased by about 5%, while its renal clearance fell by 27%, 33% and 13% after pretreatment with placebo, captopril and prazosin, respectively. The secretory clearance of the unbound furosemide changed substantially and in parallel with changes in the renal blood flow. It is suggested that changes in the renal clearance and excretion of furosemide and its t1/2 are much more dependent on changes in renal blood flow than on changes in its unbound fraction.
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  • 143
    ISSN: 1432-1041
    Keywords: Nitrendipine ; Hypertension ; pharmacokinetics ; renal function ; hypertensive crisis ; pharmacodynamics ; blood pressure ; adverse effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nitrendipine solution 5 mg·ml−1 in the dose of 5 mg was given orally to 20 patients with chronic renal failure and elevated diastolic blood pressure (≥110 mmHg), of whom 10 were on maintenance haemodialysis (endogenous creatinine clearance 〈5 ml·min−1) and 10 were at the predialysis stage (endogenous creatinine clearance 5–20 ml·min−1). The aim of the study was to investigate the influence of kidney function and/or dialysis treatment on the pharmacokinetic and pharmacodynamic profile of a solution of nitrendipine and to assess its antihypertensive efficacy. After 10 min there was a significant reduction in blood pressure from 188/113 to 173/100 (patients not dependent on dialysis) and from 197/112 to 161/94 mmHg (patients dependent on dialysis). The maximum fall in blood pressure (approximately 30%) was attained after 90 min in the dialysis patients and after 120 min in the non-dialysis group. Blood pressure increased again about 3 h after the administration of nitrendipine but it was still below baseline after 12 h. The terminal elimination half-life (4.1 h in the dialysis patients and 3.6 h in non-dialysis patients) was similar to that observed in patients with normal renal function. The pharmacokinetics of nitrendipine did not differ between the dialysis and non-dialysis groups. There was a correlation between plasma concentration and the blood pressure reduction. The maximum plasma concentration of nitrendipine was reached after 0.5 h (median) and did not differ between the two groups. The mean maximum plasma concentration was 14.8 μg·1−1 in the study population as a whole, with comparable means in the dialysis (17.3 μg·1−1) and non-dialysis (12.4 μg·1−1) groups. The nitrendipine solution proved to be effective in lowering acutely elevated blood pressure in patients with advanced renal failure and renal hypertension, and was well tolerated. The pharmacokinetics was not affected by renal impairment or by dialysis.
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  • 144
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    European journal of clinical pharmacology 45 (1993), S. 581-583 
    ISSN: 1432-1041
    Keywords: Fluocortolone ; cortisol ; pharmacodynamics ; pharmacokinetics ; adrenal suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of fluocortolone on cortisol suppression was characterized using a ‘direct suppression pharmacodynamic model’. The model incorporates the physiologic circadian secretion of cortisol under normal and treatment conditions, together with pharmacokinetic data from single fluocortolone doses of 20, 50, and 100 mg. A mean IC50 value (fluocortolone plasma concentration at which the circadian secretion of cortisol is inhibited by 50%) of 15.5 ng·ml−1 was found. This analysis shows how use of pharmacodynamic modeling can characterize dose-proportionality data to provide an in vivo measure of drug potency.
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  • 145
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    European journal of clinical pharmacology 45 (1993), S. 291-293 
    ISSN: 1432-1041
    Keywords: Moexipril ; Warfarin ; pharmacokinetics ; pharmacodynamics ; drug-interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The potential effect of moexipril, a new converting enzyme inhibitor, on the pharmacokinetics and pharmacodynamics of a single dose of warfarin has been investigated. Ten healthy male volunteers received in a randomised crossover fashion a single oral dose of 50 mg warfarin sodium alone and together with the first dose of 6 days of oral treatment with moexipril 15 mg o.d. Mean oral plasma clearance of (R)-warfarin was 175 ml·h−1 in the absence and 181 ml·h−1 in the presence of moexipril, and the corresponding values for (S)-warfarin were 248 ml·h−1 and 249 ml·h−1. Apparent volume of distribution, peak plasma concentration, time to reach peak concentration and area under the plasma concentration-time curve both of (R)- and (S)-warfarin were not significantly affected. Moexipril did not alter the maximum prothrombin time (20.3 versus 20.1 s, respectively in the absence and presence of moexipril), time to maximum response (48.0 versus 50 h) and area under the prothrombin time versus time curve. The results suggest that a clinically important interaction between moexipril and warfarin is unlikely to occur in patients treated with both drugs.
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  • 146
    ISSN: 1432-1041
    Keywords: Nimodipine ; pharmacokinetics ; Chinese patients ; acute subarachnoid haemorrhage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nimodipine pharmacokinetics was investigated in 12 Chinese patients with acute subarachnoid haemorrhage receiving an IV infusion of 1.6 or 2 mg/h (based on estimated body weight) for 10 days. Peripheral venous blood samples were collected for up to 4 days and plasma nimodipine was assayed by GC/ECD. The mean value was taken as the steady state concentration (Css) and Clearance (CL) (hourly dose/Css) was calculated. Eight survivors were given oral nimodipine (60 or 90 mg) every 6h (based on body weight), blood was sampled over 6 h and the plasma nimodipine level determined. The values for Css, CL and CL·kg−1 were 33.5 μg·l−1, 58 l·h−1 and 1.0 l·h−1·kg−1 respectively; in survivors receiving the drug orally, bioavailability of the 30 mg tablet was 9%. In one very sick patient given crushed tablets by naso-gastric tube, the AUC was very low; in vitro studies indicated that adsorption of nimodipine by the tubing was unlikely to have been the cause. The pharmacokinetic findings in Chinese patients are comparable to previously reported values in Caucasians.
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  • 147
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    European journal of clinical pharmacology 45 (1993), S. 367-371 
    ISSN: 1432-1041
    Keywords: Lansoprazole ; pharmacokinetics ; hepatic failure ; renal failure ; metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of lansoprazole (L) after a single oral dose of 30 mg was determined in 18 healthy volunteers, 17 renal failure patients and 24 hepatic failure patients; 8 hepatitis and 16 with compensated (CC) or uncompensated (UCC) cirrhosis. In renal failure, the absorption of L was unchanged, its half-life being similar to that in healthy subjects; a small change seen in mild renal failure patients (creatinine clearance between 40 and 60 ml/min) was attributed to the age of the patients. Urinary elimination, essentially as metabolites of lansoprazole, was decreased, in relation to the degree of renal impairment. In hepatitis patients, the AUC and t1/2 of L were doubled, without any change in Cmax. In cirrhotics tmax was prolonged, the AUC was increased (P〈0.001) and there was prolongation of t1/2 (6.1 h in CC and 7.2 h in UCC compared to 1.4 h in healthy subjects). These changes resulted from a decrease in the clearance of L. There was also an increase in its sulphone metabolite (Cmax, Rm) and a decrease in the hydroxylated metabolite (Cmax, Rm) in relation to the degree of liver disease, and reflecting a decrease in hydroxylation and biliary elimination. Thus, renal failure had no effect on the pharmacokinetics of L, but severe hepatic failure caused marked changes. A repeated dosing study would be necessary to evaluate the repercussions of the possible accumulation in cirrhotic patients.
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  • 148
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    European journal of clinical pharmacology 45 (1993), S. 373-376 
    ISSN: 1432-1041
    Keywords: Eptastigmine ; Cholinesterase inhibition ; Elderly subjects ; adverse effects ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Eptastigmine is a new cholinesterase inhibitor, which may be potentially useful for the symptomatic treatment of Alzheimer's disease. A preliminary evaluation of its pharmacodynamic and pharmacokinetic profiles in the elderly has now been made in 6 healthy subjects (63–84 years of age) given 30 mg eptastigmine as a single oral dose. Blood was collected prior to and 1, 2, 3, 4, 6, 8, and 12 h after eptastigmine administration for measurement of cholinesterase inhibition in plasma and red blood cells and the plasma drug concentrations. The maximum plasma cholinesterase inhibition was 17%, which was reached 2.7 h after treatment. In red cells the maximum inhibition of the enzyme was 29% after 3.8 h. The estimated half-time of cholinesterase recovery was 12.4 h in plasma and 13.6 h in red blood cells. The peak plasma concentration of eptastigmine of 0.86 ng·ml−1 was reached after 1.4 h. Following absorption the drug was rapidly distributed into tissues (t1/2α = 0.44 h) and then eliminated with a half-life of 12.1 h. The drug was well tolerated in all but one subject, who showed bradycardia with hypertension and nausea for about 2 h after the dose. The results indicate that oral administration of eptastigmine to elderly subjects produces long lasting inhibition of cholinesterase activity in plasma and in red blood cells.
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  • 149
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    European journal of clinical pharmacology 45 (1993), S. 459-463 
    ISSN: 1432-1041
    Keywords: Glyburide ; Diabetes mellitus ; pharmacokinetics ; pharmacodynamics ; obesity ; type II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the pharmacokinetics and pharmacodynamics of glyburide during long-term therapy in 20 patients with type II diabetes mellitus. The patients were divided according to body mass index (BMI) into an obese group [n=12, age 55(13) y, BMI 36.2(9.2) kg·m−2, total body weight (TBW) 100(23) kg], and a non-obese group [n=8, age 61(13) y, BMI 24.5(2.1) kg·m−2, TBW 73(7) kg]. The dosages of glyburide were titrated to achieve specified therapeutic goals based upon serum glucose concentrations or to a maximum dosage of 20 mg per day. The pharmacokinetics of glyburide were determined at week 12 of treatment. On the study day, the patients took a 2.5 mg liquid test dose of glyburide with a Sustacal meal challenge. The elimination rate constant (λz), clearance (CL), and apparent volume of distribution (Vz) were 0.08 h−1, 3.3 l·h−1, and 47.0 l in the obese group, and 0.07 h−1, 3.1 l·h−1, and 56.8 l in the non-obese group. These values were not statistically significantly different. However, there were differences between the groups when the volume and clearance were corrected by TBW or BMI but not by ideal body weight (IBW) or fat-free mass (FFM). Regression analysis between the pharmacokinetic variables and body weight status revealed statistically significant correlations between volume or clearance and body weight. However, due to large inter-patient variability, these relations were relatively weak and were considered to be non-predictive. In regard to the pharmacodynamic effects of glyburide, there were greater C-peptide and insulin responses at baseline and after 12 weeks of therapy in the obese than in the non-obese patients. However, there were no significant differences in glucose responses between the two groups. More non-obese patients needed the maximum dose (20 mg) of glyburide (7/8) compared with obese patients (6/12). These findings suggest that obese patients may be more sensitive to the effects of glyburide. Alternatively, our obese patients may have had less serious disease than our non-obese patients.
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  • 150
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    European journal of clinical pharmacology 45 (1993), S. 469-475 
    ISSN: 1432-1041
    Keywords: Cerebrospinal fluid ; Antibiotics ; Osmotic diuretics ; pharmacokinetics ; AUC ratio ; intercompartmental rate constants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Various parameters which may be useful in quantification of drug transit from blood into CSF and vice versa after a short duration infusion are compared here by recalculating previously published data from our group. Due to the slower entry into and elimination from the CSF compartment as compared to the central compartment, the ratio of drug concentrations in CSF and serum sampled at the same time increase with time after an infusion. Therefore, concentration quotients of simultaneously drawn blood and CSF are inadequate to characterise CSF penetration. The ratio of the areas under the concentration-time curves in a body fluid and serum (AUCbody fluid/AUCS) is an established measure to quantify overall penetration from the central into a peripheral compartment. AUCCSF/AUCS is closely correlated with the quotient of the maximum CSF and serum concentrations (CmaxCSF/ CmaxS) (rS=0.87, n=42, P〈0.001) and with the rate constant of distribution in CSF (CLin/VCSF) (rS=0.80, n=42, P〈0.001). Since CmaxCSF/CmaxS depends on the mode of drug administration, it is suggested that AUCCSF/AUCS be used to quantify overall drug transit into CSF. CLin/VCSF is of use when CSF can only be sampled once, or when the velocity of the transit of a drug into CSF is to be described. The CSF exit rate constant (CLout/VCSF) characterises elimination from CSF independent of the elimination from serum and may be applied to estimate the formation rate of CSF; in the present study it averaged 20 ml/h.
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  • 151
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    European journal of clinical pharmacology 45 (1993), S. 477-481 
    ISSN: 1432-1041
    Keywords: Microdialysis ; mean time parameters ; pharmacokinetics ; simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The calculation of classical pharmacokinetic parameters from microdialysis data has been described in a previous paper. In this paper I have derived methods for calculating AUMC and AUC from the time-integral type of data that are generated in microdialysis pharmacokinetics experiments. The method derived to estimate AUC is elementary, but is given a theoretical basis using principles of mathematical real analysis, clearly stating the assumptions. The method derived to estimate AUMC is a numerical approximation method based on the linear trapezoidal method. A simulation study was performed to evaluate the precision of the methods and to compare them with corresponding methods for analysis of blood sample data. The estimates from the presently derived methods have a small bias and a small variance. In the simulation study I investigated the influence of model parameters, number of samples, size of statistical error, and the size of the AUC beyond the last sample. Finally, I have given numerical examples from real data to illustrate the use of the method.
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  • 152
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    European journal of clinical pharmacology 45 (1993), S. 489-491 
    ISSN: 1432-1041
    Keywords: Tosufloxacin ; Enantiomer ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of tosufloxacin enantiomers after oral administration of racemic tosufloxacin were examined in healthy volunteers. Only small differences were observed in time to peak concentration (2.6±0.3 [mean ± SEM] h for (+)-tosufloxacin vs 2.4±0.2 h for (−)-tosufloxacin), elimination half-life (3.61±0.24 h vs 3.49±0.23 h), and area under the curve (2.78±0.19 h·μg/ml vs 2.87±0.19 h·μg/ml); however, peak concentration (0.40±0.03 μg/ml vs 0.44±0.03 μg/ml), renal clearance (226±10 ml/min vs 202±10 ml/min), and urinary recovery (35.4±2.2% vs 32.4±1.9%) differed significantly between enantiomers.
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  • 153
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    European journal of clinical pharmacology 44 (1993), S. 493-495 
    ISSN: 1432-1041
    Keywords: Timolol ; β-adrenoceptor antagonist ; transdermal ; percutaneous absorption ; skin ; pharmacokinetics ; bioavailability ; adverse effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic profiles of transdermal timolol 6 and 24 mg (as 5 and 20% w/v patches) was studied in four healthy young volunteers. To assess its bioavailability, the pharmacokinetics of an IV infusion of timolol maleate 5 mg was also determined in the same subjects. When the 20% (w/v) timolol patch was applied, the mean bioavailability was 74.4%. Plasma timolol concentrations were below the detection limit when a 5% patch was applied to the same skin area in all four subjects, except for one in whom the bioavailability was 23.6%. Weak erythema developed at the application site in all of the volunteers after application of the 20% (w/v) patch. However, erythema did not develop in any volunteer when the 5% patch was applied. The β-blocking effect was determined by exercise testing. Similar plasma levels generated similar changes in exercise-induced heart rate after the transdermal and intravenous administration of timolol.
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  • 154
    ISSN: 1432-1041
    Keywords: Bupivacaine ; wound infiltration ; postoperative ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary After routine inguinal herniorrhaphy we gave 12 patients a wound infiltration regimen of bolus doses of 20 ml of 0.5% bupivacaine via a catheter within the wound and rectally administered indomethacin (100 mg). Peak venous plasma bupivacaine concentrations ranged from 0.07 mg·l−1 to 1.14mg·l−1 (mean (SD) 0.47 (0.33) mg·l−1), and occurred at between 0.25 and 2 h after the first dose. Plasma concentrations were well below the toxic threshold of 4 mg·l−1 and there was no accumulation. The regimen provided satisfactory analgesia. There were no wound infections nor signs of toxicity.
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  • 155
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    European journal of clinical pharmacology 45 (1993), S. 165-167 
    ISSN: 1432-1041
    Keywords: Clonidine ; pharmacokinetics ; alcohol withdrawal syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have evaluated the pharmacokinetics of high doses of clonidine, as used in the prophylactic treatment of alcohol withdrawal syndrome, in 11 alcohol-dependent patients undergoing surgery for oesophagogastrectomy. Clonidine was given in a bolus of 150 μg followed by a continuous infusion. After a mean period of treatment of 9.2 (range 3 to 26) days and a mean dose of 0.72 (range 0.29 to 2.37) mg per day of clonidine the mean terminal half-life was 15.8 (range 9.9 to 23) h (n=7). In order to compare initial and terminal half-lives of clonidine intraindividually, four patients were given a bolus of 150 μg followed 24 h later by a continuous infusion. The pharmacokinetics of clonidine were described by two exponentials, with a distribution half-life of 1.2 h and a terminal half-life of 14.6 h. After a mean period of 8.3 (range 2 to 15) days and a mean dose of 0.62 (range 0.15 to 1.82) mg per day the terminal half-life in these four patients was 15.6 (range 14.0 to 17.9) h. The relation between dosage and plasma concentration was linear.
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  • 156
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    European journal of clinical pharmacology 45 (1993), S. 169-172 
    ISSN: 1432-1041
    Keywords: Fenspiride ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absolute bioavailability of fenspiride has been studied in twelve healthy volunteers. It was administered IV and orally in single doses of 80 mg fenspiride hydrochloride according to a randomised crossover pattern. Following IV administration, the plasma clearance of fenspiride was about 184 ml·min−1, and its apparent volume of distribution was moderately large (2151). When given orally as a tablet, fenspiride exhibited fairly slow ab- sorption; the maximum plasma concentration (206 ng·ml−1) was achieved 6 h after administration. The absolute bioavailability was almost complete (90%). The tablet had slow release characteristics. The elimination half-life obtained from the plasma data was 14 to 16 h independent of the route of administration.
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  • 157
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    European journal of clinical pharmacology 45 (1993), S. 181-186 
    ISSN: 1432-1041
    Keywords: Malnutrition ; Chloramphenicol ; children ; pharmacokinetics ; kwashiorkor ; marasmus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition of chloramphenicol and chloramphenicol monosuccinate has been studied in thirty-four Ethiopian children of varying nutritional status. After a single intravenous dose corresponding to chloramphenicol 25 mg per kg bodyweight, the plasma clearance of chloramphenicol monosuccinate was decreased only in severely malnourished children with kwashiorkor. Seventeen % of the dose (range 0–51%) was recovered in urine as intact prodrug, indicating incomplete and variable bioavailability of chloramphenicol. Compared to underweight children, on average marasmic and kwashiorkor subjects exhibited a 2- and 3-fold increase, respectively, in the AUC of chloramphenicol. Elevated AUCs could be traced to reduced hepatic clearance of the drug. The unbound fraction both of chloramphenicol and its prodrug were slightly elevated in serum from kwashiorkor subjects. The possibility of using a single point measurement of plasma chloramphenicol as a guide to individualized dosage are discussed.
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  • 158
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    European journal of clinical pharmacology 45 (1993), S. 191-193 
    ISSN: 1432-1041
    Keywords: Torsades de pointes ; Terfenadine ; Itraconazole ; QT-interval ; drug-interaction ; pharmacokinetics ; drug metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Terfenadine, a nonsedating H1-selective antihistamine, is widely used in many countries. We report pharmacokinetic results in a patient who developed a prolonged QT-interval in ECG and symptomatic torsades de pointes ventricular tachycardia as a consequence of the interaction of itraconazole and terfenadine. Both drugs were taken in the recommended doses: terfenadine 60 mg b.d. and itraconazole 100 mg b.d. Terfenadine metabolism was delayed by itraconazole, leading to an increased level of unmetabolised terfenadine. Seven weeks after the cessation of itraconazole treatment, terfenadine was rapidly metabolized to its active metabolite and did not prolong the QT-interval when given as a single provocation dose (120 mg). The findings suggest that intraconazole in therapeutic doses inhibits terfenadine metabolism. It is also possible that unmetabolised terfenadine alone, without an increased level of its active metabolite, may cause torsades de pointes. The concomitant use of terfenadine and itraconazole (and ketoconazole) should be avoided.
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  • 159
    ISSN: 1432-1335
    Keywords: p53 ; Pyrimidine dimer ; Immunohistochemistry ; Solar keratosis ; UV
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to find biomarkers to measure the effects of UV irradiation, we examined the accumulation of p53 protein and pyrimidine dimers in 18 solar keratosis specimens. Frozen or AMeX-fixed solar keratosis specimens were immunohistochemically stained by anti-p53 mouse monoclonal antibody, pAb1801 and polyclonal anti-(pyrimidine dimer) antibody. Nuclear accumulation of p53 protein was found in 5/18 (28%) solar keratosis lesions. The percentage of cases showing nuclear p53 protein varied according to the histological type; in the bowenoid type it was 4/7 (57%); in the atrophic type it was 1/7 (14%). Nuclear pyrimidine dimers were not stained in solar keratosis, although the skin of UV-irradiated nude mice was positive. Accumulation of p53 protein is a good marker for early precancerous change caused by UV exposure.
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  • 160
    ISSN: 1432-1335
    Keywords: Carcinoma ; Gallbladder ; Immunology ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Forty-three patients with invasive adenocarcinoma of the gallbladder were postoperatively studied in order to determine their general immunological status as well as the local immunohistological reaction to the tumor. At the end of the follow-up, they formed two groups: 19 living patients (group GL) and 24 dead patients (group GD). As a control group (GC), 21 patients with cholecistectomy for cholelithiasis and without carcinoma were simultaneously evaluated. In GL, most of the tumors were limited to the gallbladder wall, and in GD, most of the tumors were already disseminated at the time of diagnosis. GD presented a lower percentage of peripheral blood B lymphocytes, as compared to GL and GC cases. Skin tests of delayed hypersensitivity were significantly more reactive in GL cases than in GD cases, and less reactive in GD than in GC cases. The immunohistological evaluation of the gallbladder yielded a lower B lymphocyte infiltration in GD tumors than in the control cases. GL cases showed a higher intratumoral lymphocytic and mononuclear cell infiltration than GD cases. Although the clinical stage was higher in GD than in GL cases, there were also significant differences in the local immune response and the general immunological status. Patients with invasive gallbladder adenocarcinoma showing longer postoperative survival revealed normal or increased local and general immunological reactions, whereas patients with disseminated tumors showed an important humoral and cellular secondary immunodeficiency.
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  • 161
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    Journal of cancer research and clinical oncology 119 (1993), S. 507-510 
    ISSN: 1432-1335
    Keywords: Immunohistochemistry ; Oncoproteins ; Squamous cell lung carcinoma ; Survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The expression of the oncogenes c-fos, c-jun, c-myc, c-erbB-1 and c-erbB-2 at the protein level was analyzed in squamous cell lung carcinomas of 121 patients by means of immunohistochemistry. Patients with overexpression of proteins encoded by the oncogenes c-fos, c-jun and c-erbB-1 had significantly shorter survival times than these without overexpression of these oncogene products (c-fos:p=0.009; c-jun:p=0.029; c-erbB-1:p=0.018). No significant correlations were found between the expression of c-myc and c-erbB-2 products and the survival of the patients. In addition to the univariate analyses (Kaplan-Meier-estimates) multivariate analyses (Cox-regression-model) revealed that protein expression of the oncogenes c-fos, c-jun and c-erbB1 are significant prognostic factors in addition to staging.
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  • 162
    ISSN: 1432-1335
    Keywords: p53 protein ; Point mutation ; Osteosarcoma ; Bone tumour ; Immunohistochemistry ; Immunoelectron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Alterations of tumour suppressor genes are considered crucial steps in the development of human cancers. Expressions of p53 protein, a product of the tumour suppressor gene altered most commonly in human cancers examined so far, were investigated immunohistochemically in 18 osteosarcomas and 40 other malignant and benign lesions of bone. A monoclonal antibody clone PAb240, which recognizes a common conformational epitope of mutant p53 proteins, stained nuclei of tumour cells in 12 of 18 osteosarcomas (67%). Six tumours (33%) particularly showed positive immunoreactions in more than half of the tumour cells. PAb240 also stained tumour cells in a small number of other malignant bone tumours, such as malignant fibrous histiocytoma, chondrosarcoma, and Ewing's sarcomas. Furthermore, a small number of cells of giant-cell tumours were positively stained. In contrast, PAb240 was completely negative in 21 benign bone tumours and reactive lesions examined. Another monoclonal antibody clone PAb1801, which reacts with both wild- and mutant-type p53 protein, reacted in nuclei of tumour cells of 7 osteosarcomas (39%). Most of those also reacted with PAb240. PAb1801 was expressed much more frequently in other malignant bone tumours and giant-cell tumours. In addition, PAb1801 showed intranuclear positive reactions in tumour cells of a benign chondroblastoma, and reactive cells such as actively proliferating preosteoblasts in a myositis ossificans and osteoclast-like giant cells in a giantcell tumour. The immunoelectron-microscopic observation that p53 protein was localized in euchromatic areas of nuclei of osteosarcoma cells supported the specificity of immunoreaction for p53 protein, indicating an active role of p53 protein in the regulation of DNA synthesis and transcription. These findings suggest that point mutation of the p53 gene is frequently involved in the development of osteosarcomas. PAb240 may be a useful tool not only in screening point mutations of the p53 gene in osteosarcomas but also in the differential diagnosis between osteosarcomas and reactive bone-forming lesions. Expressions of mutant p53 protein were not correlated with any clinical or pathological factors examined, although the results should be confirmed in studies of a large number of osteosarcomas.
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  • 163
    ISSN: 1432-1335
    Keywords: Chondrosarcoma ; Enchondroma ; Collagen IX ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The distinctive tissue localization of collagen types, particularly of type IX collagen in human cartilaginous tumors (10 cases of enchondroma and 15 cases of chondrosarcoma including 3 cases of secondary chondrosarcoma) was examined immunohistochemically using affinitypurified antibodies against types I, II, III, V, VI, and IX collagen, in comparison with that in human fetal cartilage. In fetal cartilage matrix, types II and IX collagen were diffusely distributed, while types I, III, and V collagens were not present. In the matrices of enchondromas and primary chondrosarcomas, types II and IX collagens were also diffusely distributed, but with some areas of irregular type IX collagen deposits. The secondary chondrosarcoma simulated normal fetal cartilage in the distribution pattern of types II and IX collagen, unlike the pattern in primary chondrosarcoma, where types II and IX collagen were decreased and poorly immunostained, whereas non-cartilaginous interstitial collagens (I, III, and V) appeared diffusely in the matrix, increasing with the grade of malignancy. These findings suggest that neoplastic cartilage is characterized initially by an uneven distribution of type IX collagen, prior to any alteration of other types of collagen; the diverse expressions of intercellular components in cartilaginous tumors may be one indicator for malignancy.
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  • 164
    ISSN: 1432-0878
    Keywords: Met-enkephalin ; Immunohistochemistry ; Intestine, small ; Neuron, enteric ; Laser microsurgery ; Rana catesbeiana (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerve elements in the small intestine of the bullfrog. Rana catesbeiana, were studied by immunohistochemistry with anti-methionine enkephalin antisera and by nerve lesion experiments, using laser irradiation. Methionine-enkephalin immunopositive nerve fibers occur in the myenteric plexus, circular muscle layer, submucosa, and mucosa. Immunopositive nerve cell bodies in the myenteric plexus have dendrite-like and a long axon-like processes. In the froglet (3 months after metamorphosis), these axon-like processes lead posteriorly in the nerve strand of the myenteric plexus. Some bifurcate, one branch continuing posteriorly, the other doubling back to lead anteriorly; both form terminal varicose fibers in the circular muscle layer. Nerve lesion experiments, in the adult bullfrog, resulted in accumulations of methionine-enkephalin immunoreactivity at the oral and hinder edges of the laser-irradiated necrotic area; there were sprouting and nonsprouting immunopositive stumps. It is suggested that bidirectional flow of methionine-enkephalin in the myenteric plexus is mediated via the anterior and posterior branches of the axon-like process. The difference in sprouting behavior of immunopositive nerve fiber stumps, after nerve lesion, is discussed with reference to regional differences of the axon-like process.
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  • 165
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    Cell & tissue research 272 (1993), S. 147-154 
    ISSN: 1432-0878
    Keywords: Histamine ; Immunohistochemistry ; Brain, vertebrate ; Catecholamines ; Triturus carnifex (Urodela)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of immunoreactivity for histamine was studied in the brain of the urodele Triturus carnifex using the indirect immunofluorescence method. Histamine-immunoreactive cell bodies were localized in the caudal hypothalamus within the dorsolateral walls of the infundibular recesses. These immunoreactive cell bodies were pear-shaped, bipolar and frequently of the cerebrospinal-fluid-contacting type. Histaminergic nerve fibers were detected in almost all parts of the brain. Dense innervation was seen in the telencephalic medial pallium and ventral striatum, the neuropil of the preoptic area, the septum, the paraventricular organ, the posterior commissure, the caudal hypothalamus, the ventral and lateral mesencephalic tegmentum. Medium density innervation was observed in the lateral mesencephalic tegmentum and optic tectum. Poor innervation was present in the telencephalic dorsal pallium and in the central gray of the medulla oblongata. Few fibers occurred in the olfactory bulbs and in the telencephalic lateral pallium. Double immunofluorescence staining, using an antibody against tyrosine hydroxylase, showed that histamine-immunostained somata and those containing tyrosine-hydroxylase-like immunoreactivity were co-distributed in the tuberal hypothalamus. No co-occurrence of histamine-like and tyrosine hydroxylase-like immunostaining was seen in the same neuron. The pattern of histamine-immunoreactive neurons in the newt was similar to that described in other vertebrates. Our observations, carried out on the apparently simplified brain of the newt confirm that the basic histaminergic system is well conserved throughout vertebrates.
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  • 166
    ISSN: 1432-0878
    Keywords: Immunohistochemistry ; Pelvic nerves ; Neuropeptides ; Large intestine ; Bufo marinus (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution and colocalization of neuropeptides and 5-hydroxytryptamine in the posterior portion of the large intestine of the toad was studied using single- and dual-label immunohistochemistry. Neurons containing colocalized galanin/somatostatin or vasoactive intestinal peptide alone were observed along intramural pelvic nerves. Some of the galanin/somatostatin neurons also contained 5-hydroxytryptamine. Synaptic boutons containing colocalized calcitonin gene-related peptide/vasoactive intestinal peptide were associated with the galanin/somatostatin neurons. The muscle of the large intestine was also innervated by axons containing galamin/somatostatin, vasoactive intestinal peptide/calcitonin gene-related peptide or vasoactive intestinal peptide alone. Nerve fibres containing calcitonin gene-related peptide/substance P, probably representing primary afferent nerves, were also associated with muscle bundles. Submucosal blood vessels carried dense plexuses of fibres containing vasoactive intestinal peptide alone or and calcitonin gene-related peptide/substance P. Adrenergic perivascular nerves also contained galanin and neuropeptide Y.
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  • 167
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    Cell & tissue research 273 (1993), S. 467-474 
    ISSN: 1432-0878
    Keywords: Basic fibroblast growth factor ; Salivary glands ; Cell growth assay ; Immunohistochemistry ; Radioimmunoassay ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We studied the occurrence and localization of basic fibroblast growth factor (bFGF) in rat salivary glands using a specific monoclonal antibody. It was shown that the extract of rat salivary glands has a pronounced stimulatory activity on the growth of bovine capillary endothelial cells, which is blocked by the addition of an antibody against bFGF. The concentration of bFGF in the submandibular/sublingual gland, as determined by radioimmunoassay, was ∼80% that in the brain. Immunocytochemistry revealed bFGF-immunoreactivity localized primarily in the epithelial cells lining the striated ducts and excretory ducts of the parotid, sublingual and submandibular glands. In addition, intense bFGF-immunoreactivity was observed in the granular convoluted tubule of the submandibular gland, localized predominantly in the agranular pillar cells, which lay in small numbers among the majority of weakly immunostained cells containing many apical secretory granules. At the electron-microscopic level, the immunoreactive material was distributed diffusely in the cytoplasmic matrix and nuclei of all immunoreactive cells, whereas it was absent from all cytoplasmic organelles including the secretory granules. These results indicate that bFGF is localized in different cellular and subcellular compartments from those of other growth factors in the duct system of rat salivary glands.
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  • 168
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    Cell & tissue research 273 (1993), S. 547-555 
    ISSN: 1432-0878
    Keywords: Pancreas, endocrine ; Immunohistochemistry ; Neuropeptide Y ; Peptide YY ; FMRFamide ; LPLRFamide ; Vasoactive intestinal polypeptide (VIP) ; Oncorhynchus mykiss (Teleostei) ; Gadus morhua (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Endocrine cells exhibiting immunoreactivity to FMRFamide-like, LPLRFamide-like, neuropeptide Y(NPY)-like and peptide YY(PYY)-like peptides were found in the periphery of the Brockmann bodies of the cod, Gadus morhua, and rainbow trout, Oncorhynchus mykiss. No immunoreactivity or very weak labelling was found with antisera to pancreatic polypeptide (PP). Vasoactive intestinal polypeptide (VIP)-like immunoreactivity was found in nerve fibres, whereas labelling with VIP antiserum in endocrine cells disappeared after preincubation with nonimmune serum. There were always more immunoreactive cells in the rainbow trout than in the cod. No immunoreactivity could be seen with antisera to gastrin/cholecystokinin (CCK) or enkephalin. Double-labelling studies were performed to study the colocalization of the peptides in peripheral endocrine cells. Cells immunoreactive to NPY were also labelled with antisera to FMRFamide, LPLRFamide and PYY. The co-localization pattern of NPY varied; in some Brockmann bodies, a population of the immunoreactive cells showed co-localization and others contained NPY-like immunoreactivity only, whereas in other Brockmann bodies, all NPY-labelled cells also contained FMRFamide-like, LPLRFamide-like and PYY-like immunoreactivity. Cells immunoreactive to PYY similarly contained FMRFamide-like, LPLRFamide-like and NPY-like immunoreactivity, comparable to the patterns observed with NPY. Glucagon-like immunoreactivity was found at the periphery of the Brockmann bodies. A subpopulation of the glucagon-containing cells contained NPY-like immunoreactivity. PYY-like immunoreactivity was also found co-localized with glucagon-like immunoreactivity, as were FMRFamide-like and LPLRFamide-like immunoreactivity. Therefore, either NPY-like and PYY-like immunoreactivity together with FMRFamide-like and LPLRFamide-like immunoreactivity occur in the same endocrine cells of the Brockmann body of the cod and rainbow trout, or a hybrid NPY/PYY-like peptide recognized by both NPY and PYY antisera is present in the Brockmann body.
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  • 169
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    Cell & tissue research 274 (1993), S. 181-187 
    ISSN: 1432-0878
    Keywords: Neuropeptides ; Stellate ganglion ; Immunohistochemistry ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The localization and distribution of neuropeptides including neuropeptide Y (NPY), [Met5]enkephalin-Arg6-Gly7-Leu8 (MEAGL), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), substance P and somatostatin (SOM) were analyzed in the stellate ganglion of the pig by use of the indirect immunofluorescence technique. NPY, MEAGL, SOM, VIP and CGRP immunoreactivities were found to exist in subpopulations of neuronal cell bodies of the stellate ganglion. A population of the small intensely fluorescent (SIF) cells showed MEAGL immunoreactivity. In addition, the presence of NPY-, MEAGL-, CGRP-, SP-, SOM- and VIP-immunoreactive nerve fibers and axonal varicosities were observed in the stellate ganglion. The localization and pattern of distribution of these peptides in the porcine stellate ganglion were compared with studies carried out on stellate ganglia of other mammalian species.
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  • 170
    ISSN: 1432-0878
    Keywords: Vasoactive intestinal polypeptide ; Neuropeptide Y ; Enkephalin ; Calcitonin gene-related peptide ; Galanin ; Immunohistochemistry ; Enteric nervous system ; Oreochromis mossambicus, Carassius auratus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The presence of bioactive peptides in the gut and their possible electrophysiological effects on the intestinal epithelium were studied in two teleost species, the tilapia (Oreochromis mossambicus) and the goldfish (Carassius auratus). Vasoactive intestinal polypeptide-like immunoreactive nerve fibres were found beneath the intestinal epithelium of both species. Galanin-, metenkephalin-and calcitonin gene-related peptide-like immunoreactive nerve fibres were found exclusively in the mucosa of the tilapia. Both species had vasoactive intestinal polypeptide-, enkephalin- or neuropeptide Y-like immunoreactive endocrine cells; calcitonin gene-related peptide-like immunoreactive endocrine cells were additionally found in the tilapia. Somatostatin- and dopamine-β-hydroxylase-like immunoreactivities were not observed. Nerve cell bodies in the myenteric plexus of both species showed immunoreactivity for calcitonin gene-related peptide-, vasoactive intestinal polypeptide-, and galanin-like peptide. Enkephalin-like immunoreactive nerve cell bodies were present in the tilapia only. None of the peptides had a pronounced electrogenic effect. However, calcitonin gene-related peptide added to stripped intestinal epithelium of the tilapia, reduced the ion selectivity, and addition of galanin increased the ion selectivity. In goldfish intestine, both galanin and calcitonin gene-related peptide were without effect. Enkephalin counteracted the serotonin-induced reduction of the ion selectivity of the goldfish intestinal epithelium, but had no effect on the tilapia epithelium. In both species, vasoactive intestinal polypeptide reduced the ion selectivity of the intestinal epithelium, and neuropeptide Y induced an increase of the ion selectivity. Somatostatin showed no effect on the epithelial ion selectivity of either species. Tetrodotoxin did not inhibit the effects of the peptides studied. The changes in ion selectivity suggest that the enterocytes may be under the regulatory control of these peptides.
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  • 171
    ISSN: 1432-0878
    Keywords: Neuropeptide Y ; Brain, vertebrate ; Hypothalamus ; Pituitary gland, pars nervosa ; Immunohistochemistry ; Paramyxine atami (Cyclostomato)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of neuropeptide Y-like immunoreactivity in the brain and hypophysis of the brown hagfish, Paramyxine atami, was examined by use of the peroxidase-antiperoxidase method. Immunoreactive cells were found in two areas of the brain, the nucleus hypothalamicus of the diencephalon and the ventrolateral area of the caudal tegmentum, at the level of the nucleus motorius V–VII. The labeled cells of the nucleus hypothalamicus were loosely grouped and recognized as bipolar neurons. Immunolabeled fibers were widely distributed in the brain, showing the highest density in the diencephalon. They were sparse, or absent, in the olfactory bulb, habenula, primordium hippocampi, neurohypophysis, corpus interpedunculare, and dorsolateral area of the medulla oblongata. The fibers appeared to project exclusively from the ventral hypothalamus to various other portions of the brain: the anterolateral areas of the telencephalon via the basal hypothalamus, the pars dorsalis thalami, the dorsocaudal region of the mesencephalon, and the ventromedial portions of the tegmentum and anterior medulla oblongata. These findings suggest that, in the brown hagfish, NPY-like substance is involved in neuroregulation of various cerebral areas, but it may be of little significance in the control of pituitary function.
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  • 172
    ISSN: 1432-0878
    Keywords: Caudal neurosecretory system ; Urophysis ; Urotensins ; Immunohistochemistry ; Development, ontogenetic ; Oncorhynchus keta (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In order to make an immunohistochemical analysis of the development of the caudal neurosecretory system of the chum salmon, Oncorhynchus keta, we employed the peroxidase-anti-peroxidase technique using antisera specific for urotensins (U) I and II on artificially reared embryos, larvae, and juveniles of this species. Immunoreactivities for UI and UII were first demonstrated in the embryo immediately before hatching, showing labeled perikarya and fibers in the most caudal region of the spinal cord where the presumptive caudal neurosecretory system is located. However, distinct differentiation of the histological neurohemal organ had not yet begun in the embryo. Immunoreactive perikarya and fibers gradually increased in number, and an elaborate urophysis comparable to that of adults was demonstrated in the larvae about 5 months after hatching. At this stage, weak immunoreactivity against UI was detected in the neurohypophysis.
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  • 173
    ISSN: 1432-0878
    Keywords: Nasal-associated lymphoid tissue ; Reticulam cells ; Immunohistochemistry ; Rat (Wistar, Brown-Norway)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This study concerns the ontogeny of reticulum cells (RC) in the nasal-associated lymphoid tissue (NALT) of Wistar and Brown-Norway rats. A panel of monoclonal antibodies (mAb) directed against RC in peripheral lymphoid organs (antibodies ED10≈ED15) was used, together with a recently developed antibody ED17, which recognizes macrophages and Langerhans cells. Early in embryogenesis, staining with common connective tissue markers, ED14 and ED15, was found. ED17-positive cells were present before cells positive to ED1, a pan-macrophage marker, or Ia glycoproteins were observed. The first differentiation of reticulum was seen at the day of birth, when ED10 recognized a distinct area in the nasal mucosa. The first T-lymphocytes were found at the same time. Two days after birth, B-cells and ED11-positive cells were present in the NALT area. Fourteen days after birth, T- and B-cell compartments were recognizable. ED10 was found predominantly in the T-cell area and ED11 was mainly confined to the B-cell compartment. We conclude that the development of the NALT is closely accompanied by the phenotypic specialization of the reticulum. This suggests that the reticulum plays an important role in the compartmentalization of NALT tissue and in the retention of lymphocyte subsets within these compartments.
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  • 174
    ISSN: 1432-0878
    Keywords: Adrenal medulla ; Grafts ; Cholinergic immunophenotype ; Hippocampus ; Immunohistochemistry ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The development of neuron-like cholinergic immunophenotypes by adrenal chromaffin cells was studied in 10-week-old mouse adrenal medullary grafts. Fragments of chromaffin tissue were implanted into mouse hippocampus, and antibodies specific for neurofilaments (NF), neuron-specific enolase (NSE), choline acetyltransferase (ChAT), acetylcholinesterase (AChE), and phenylethanolamine-N-methyltransferase (PNMT) were applied to the grafts. Adrenal medulla grafts survived well and most of the transplanted cells were either round or polygonal. A minority of chromaffin cells elaborated an intermediate or sympathetic neuron phenotype. Chromaffin cells showed pronounced immunoreactivity for NSE in their perikarya and axon-like processes: immunoreactivity for NF was only found in a few processes. In adjacent immunohistochemically stained sections, the transplanted cells stained for ChAT and AChE. At the electron-microscope level, the immunohistochemical reactions for the two acetylcholine-related enzymes were mainly located on the endoplasmic reticulum and in cell processes. Immunoreactivity for PNMT was found to decline in transplanted chromaffin cells below that of normal adrenal medulla. These observations suggest that, in adrenal medullary grafts implanted into the hippocampus, chromaffin cells are endowed with neuron-like cholinergic immunophenotypes.
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  • 175
    ISSN: 1432-0878
    Keywords: Umbilical cord ; Placenta ; Basal plate ; Endothelial cells ; Immunohistochemistry ; Lectins ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The heterogeneity of endothelial cell surface antigen expression was studied in 5 human full-term placentae by means of indirect immunohistochemistry using 9 monoclonal antibodies and by staining with fluorescent-conjugated Ulex europaeus lectin, both of which are widely used endothelial cell markers. (1) A highly specific, homogeneous staining of fetal and maternal placental vessels of all sizes and anatomical regions was observed by the monoclonal antibodies PAL-E, QBEND10 and 1F10. These antibodies were even more specific than Ulex europaeus lectin, factor VIII antibody and von Willebrand factor antibody, which cross-reacted with some non-endothelial cells and structures. The reactivity of PAL-E, QBEND10 and 1F10 with residual surface cells of the basal plate strongly suggests an endothelial origin of these cells. (2) In contrast to other organs, PAL-E, QBEND10 and HM 15/3 strongly stained endothelial cells of the macrovascular system in the human placenta. This might indicate an organ-associated heterogeneity of fetal endothelial cells. (3) Monoclonal antibodies against receptors for transferrin and IgG (FcγRII) labeled the endothelial cells of fetal placental vessels with increasing intensity distal to the insertion of the umbilical cord. The vessels of the umbilical cord itself were unreactive. This might suggest a heterogeneity of macro- and microvascular endothelial cells.
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  • 176
    ISSN: 1432-0878
    Keywords: Insect neryous system ; Histamine ; Neurotransmitter ; Immunohistochemistry ; Mechanosensory receptors ; Drosophila melanogaster, Musca domestica (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Histamine is known to be the neurotransmitter of insect photoreceptors. Histamine-like immunoreactivity is also found in a number of interneurons in the central nervous system of various insects. Here, we demonstrate by immunohistochemical techniques that, in Drosophila melanogaster (Acalypterae), most or all mechanosensory neurons of imaginal hair sensilla selectively bind antibodies directed against histamine. The histamine-like staining includes the cell bodies of these neurons as well as their axons, which form prominent fibre bundles in peripheral nerves, and their terminal projections in the central neuropil of head and thoracic ganglia. The specificity of the immunostaining is demonstrated by investigating a Drosophila mutant unable to synthesize histamine. Other mechanosensory organs, such as campaniform sensilla or scolopidial organs, do not stain. In the calypteran flies, Musca and Calliphora, we find no comparable immunoreactivity associated with either hair sensilla or the nerves entering the central nervous system, observations in agreement with earlier studies on Calliphora. Thus, histamine seems to be a major mechanosensory transmitter candidate of the adult nervous system of Drosophila, but apparently not of Musca or Calliphora.
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  • 177
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    Cell & tissue research 273 (1993), S. 239-247 
    ISSN: 1432-0878
    Keywords: Vasopressin ; Neurophysin ; Vasoactive intestinal peptide (VIP) ; Immunohistochemistry ; Suprachiasmatic nucleus ; Hypothalamus ; Circadian Rhythms ; Mink Mustela vison (Carnivora) ; Rat (Wistar) ; Golden hamster Mesocricetus auratus ; Mongolian gerbil, Meriones unguiculatus Rodentia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The hypothalamic suprachiasmatic nucleus is centrally involved in generation of several circadian rhythms. Neurons of the mammalian suprachiasmatic nucleus express a number of neuropeptides including vasopressin. The suprachiasmatic nucleus of the mink (Mustela vison) is easily distinguished from neighbouring hypothalamic areas and the underlying optic chiasm as a small nucleus containing densely packed parvocellular neurons. A dorsal and ventral subdivision were clearly recognized within the midportion and caudal part of the nuclcus. Using immunohistochemistry, we have identified vasopressin-, neurophysin-, and vasoactive intestinal peptide-immunoreactive neuronal elements in the hypothalamus of the mink. Vasoactive intestinal peptide-immunoreactive neurons can be observed in the ventral aspect of the suprachiasmatic nucleus, but to our surprise, no vasopressin immunoreactive perikarya are found within the suprachiasmatic nucleus, this absence being independent of the experienced annual cycle. The hypothalamic paraventricular and supraoptic nuclei contain large numbers of vasopressin-, neurophysin-and vasoactive intestinal peptide-immunoreactive magnocellular neurons with extensive projections towards the infundibulum and neurohypophysis. A comparative analysis of the distribution of vasopressin-immunoreactive elements in a number of conventional laboratory animals has demonstrated that, in contrast to the rat, golden hamster and Mongolian gerbil, neither vasopressin-containing perikarya in the suprachiasmatic nucleus nor fine calibered immunoreactive fibres entering the adjacent subparaventricular zone are present in the mink. The mink is a photodependent seasonal breeder, and thus vasopressin-immunoreactive neurons in the suprachiasmatic nuclei may not be essential for the photoperiodic regulation of reproduction and seasonal events experienced by this species.
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  • 178
    ISSN: 1432-0878
    Keywords: Tubouterine junction ; Innervation ; Immunohistochemistry ; Acetylcholinesterase ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The innervation of the bovine tubouterine junction was studied in sexually mature heifers using antisera against various neuronal markers and a modified acetylcholinesterase method. The vast majority of the nerve fibres in the bovine tubouterine junction belongs to the sympathetic nervous system; peptidergic and cholinergic fibers are restricted to characteristic locations. The endosalpinx in the adovarian portion of the terminal tubal segment is poorly innervated. The mucosa of the aduterine portion and of the tubouterine transitinal region proper receives a strikingly dense innervation, which is observed mainly in combination with a strong vascularisation of specialised mucosal structures. In the endometrium, perivascular nerves accompany the ascending spiral arteries but sporadic contacts between nerve fibres and uterine glands are also observed. From the muscular coat the inner longitudinal layer of the terminal tubal segment is more richly supplied by nerve fibres than the intermediate circular and outer longitudinal layers of the tubouterine junction. No changes in the innervation pattern were seen during the different stages of the sexual cycle.
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  • 179
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    Cell & tissue research 273 (1993), S. 533-545 
    ISSN: 1432-0878
    Keywords: Immunohistochemistry ; Neurotransmitters ; Neuromodulators ; Histamine ; Visual system ; Nervous system, central ; Cupiennius salei (Arachnida)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In this study, immunohistochemistry on Vibracut sections is used to demonstrate anti-histamine immunoreactivity in the brain of the spider, Cupiennius salei (Keys.) (Ctenidae). We describe a system of histamine-immunoreactive neurons within the central nervous system that consists of six omnisegmental neurons. These histamine-immunoreactive neurons form two subgroups: a dorsal system with two cells per hemisphere and a ventral system with only one cell per hemisphere. The cells have extended arborizations in the motor and sensory areas of all neuromeres in the suboesophageal ganglionic mass. We have also found histamine immunoreactivity in the photoreceptors of C. salei and suggest that histamine is a neurotransmitter of photoreceptors in all arthropods, since it is also known to occur in the photoreceptors of the other main arthropod taxa (Merostomata, Crustacea, and Insecta).
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  • 180
    ISSN: 1432-0878
    Keywords: Connexin43 ; Gap junction ; Muscularis externa ; Intestine ; Coronary artery ; Immunohistochemistry ; Mouse ; Dog ; Man ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Electron-microscopic studies have revealed a heterogeneous distribution of gap junctions in the muscularis externa of mammalian intestines. This heterogeneity is observed at four different levels: among species; between small and large intestines; between longitudinal and circular muscle layers; and between subdivisions of the circular muscle layer. We correlated results obtained with two immunomethods, using an antibody to the known gap-junctional protein (connexin43) with ultrastructural findings, and further evaluated the respective sensitivity of these two approaches. For comparative reasons we also included the vascular smooth muscle of coronary arteries into our study. Two versions of the immunotechnique (peroxidase-antiperoxidase and fluorescence methods) were applied to frozen sections of murine, canine, and human small and large intestines, as well as to pig coronary artery. In the small intestine of all three species a very strong reactivity marked the outer main division of the circular muscle layer, while the longitudinal muscle layer as well as the inner thin division of the circular muscle layer were negative. In murine and human colon both muscle layers were negative, while in canine colon the border layer between the circular muscle and the submucosa reacted strongly, and scattered activity was found in the portion of the circular muscle layer (one tenth of its thickness) closest to the submucosa. The remainder of the circular muscle layer and the entire longitudinal muscle layer were negative in the canine colon. In the coronary artery we could not confirm the positive, specific labeling reported by other investigators (l.c.). In conclusion, we found close correlations at all four above-mentioned levels in the distribution of gap junctions in the gut musculature, as determined by binding of anticonnexin43 in comparison to conventional ultrastructural studies. Since no significant immunostaining was found in (i) the outer border of the circular muscle layer of the canine colon and (ii) the border layer between the submucosa and the circular muscle layer of human colon, where rare gap junctions have been identified at the ultrastructural level, we conclude that the electron-microscopic analysis is the more sensitive of the two methods.
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  • 181
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    Cell & tissue research 272 (1993), S. 383-389 
    ISSN: 1432-0878
    Keywords: Mammary gland ; Growth inhibitor ; Epithelium ; Cell types ; Differentiation ; Immunocytochemistry ; Immunohistochemistry ; Cow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Localization of a mammary-derived growth inhibitor (MDGI) in the bovine mammary gland was verified by light-and electron-microscopic methods. Expression of MDGI, which is known to inhibit the growth of mammary epithelial cell lines in vitro, was found to be highest in the late pregnant and in the lactating state. A combination of immunohistochemical and immunocytochemical methods with semi- and ultrathin resin sections revealed marked variations in MDGI staining. High MDGI levels were predominantly detectable in epithelial cells with large milk fat droplets. Distinct cell types that were almost free of label could be identified among bovine mammary epithelial cells that always exhibited high MDGI levels. Similar results were obtained when using a serum-free organ culture system in which MDGI was hormonally induced in cell types of comparable differentiation state. The specific occurrence of the growth inhibitor in developing alveoli and certain cell types points to the association between MDGI expression and functional differentiation in the normal mammary gland.
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  • 182
    ISSN: 1432-0878
    Keywords: Basic fibroblast growth factor ; Trigeminal ganglion ; Immunohistochemistry ; Electron microscopy ; In situ hybridization histochemistry ; Vibrissae ; Hair ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have characterized an antiserum against basic fibroblast growth factor (bFGF) by immunoblot, investigated the location of bFGF-like immunoreactivity (bFGF-IR) in the trigeminal sensory system and perioral skin endowed with vibrissae, and demonstrated the site of bFGF mRNA expression in the vibrissae by in situ hybridization histochemistry. Light-microscopic immunohistochemistry has demonstrated that bFGF-IR is present not only in trigeminal ganglion neurons and their central and peripheral processes, but also in cells of the matrix, external root sheath and papillae of vibrissae and the stratum basale of the stratified squamous epithelium of the skin. Electron microscopy has revealed intense bFGF-IR mainly in cytoplasmic regions, other than the lumen of rough endoplasmic reticulum and the Golgi apparatus, in trigeminal ganglion neurons, in fibroblast-like cells in the papillae, and in capsules of vibrissae. In contrast, actively proliferating and/or differentiating cells in the matrix of vibrissae have intensely stained euchromatin and weakly labeled cytoplasm that, unlike that of the aforementioned cells, contain immunoreaction products in discrete spots less than 100 nm in diameter, implying the generation of different molecular forms of bFGF in cells of the matrix and papillae. Moreover, the accumulation of bFGF in the euchromatin appears to take place in cells at non-mitotic stages (possibly interphases), characterized by a conspicuous nucleolus and well-developed nuclear envelope. A digoxigenin-labeled cRNA probe for the demonstration of bFGF mRNA gives conspicuous hybridization signals mainly in the matrix of vibrissae. These findings suggest that bFGF is involved in the growth and differentiation of matrix cells during certain periods of the cell cycle and that it acts as a non-mitogenic mediator in the adult trigeminal sensory system.
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  • 183
    ISSN: 1432-0878
    Keywords: Chromogranins ; Serotonin ; Histamine ; Regulatory peptides ; Gut ; Monoclonal antibodies ; Immunohistochemistry ; Podarcis sicula (Lacertilia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution, argyrophilia, and the possible amine/peptide co-localizations in endocrine cells immunoreactive (IR) to antisera against chromogranin A (CgA) and chromogranin B (CgB) in the alimentary tract of the lizard Podarcis sicula have been investigated using novel monoclonal antibodies. Many CgA-IR and CgB-IR cells were found in the tract, except in the distal small intestine. Almost all chromogranin-IR cells (Cgs-IR) were also argyrophilic with parallel intensity. Some CgA-IR and CgB-IR cells did not display co-localized amines or peptides. CgA or CgB or both were found co-localized, with some local differences, in almost all serotonin-IR, histamine-IR, substance P-IR and gastric peptide tyrosine tyrosine (PYY)-IR cells. Moreover, both Cgs were co-localized only in some somatostatin-IR cells, whereas neurotensin-IR, gastrin/cholecystokinin-IR, pancreatic polypeptide-IR and intestinal PYY-IR cells did not show any co-localization with Cgs. The presence of Cgs in the endocrine cells was heterogeneous with regard to the complex interrelationship with their amine/peptide content. Consequently, Cgs cannot be considered as universal “markers” of all endocrine cell types.
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  • 184
    ISSN: 1432-0878
    Keywords: Serotonin ; Alimentary canal, insect ; Stomatogastric neryous system ; Immunohistochemistry ; Bioassay ; Electron microscopy ; Leptinotarsa decemlineata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Immunohistochemical studies showed that the alimentary canal of Leptinotarsa decemlineata receives serotoninergic innervation from different neurons in the central and stomatogastric nervous system. The foregut is innervated by the frontal ganglion. Four of the 6–8 large neurons present in this ganglion have axons which run to the musculature of the oesophagus, crop, sphincter, and frontal area of the midgut. They are accompanied by axons from neurons in the suboesophageal ganglion, and by axons from as yet unidentified non-immunoreactive neurons in thebrain and/or the ventral nerve cord. The posterior part of the midgut is essentially devoid of serotoninergic innervation. The hindgut is innervated by two large neurons in the caudal tip of the last abdominal ganglion. The axons always run to the circular and longitudinal muscles of the crop, the circular muscles of the sphincter, and the longitudinal muscles of the hindgut. Immunohistochemical electron microscopy suggests that exocytosis of the immuno-labelled vesicles may occur at some distance from the muscle fibres, implying a neurohormonal release of this neurochemical. A bioassay used to demonstrate the type of effect of serotonin on isolated hindguts in vitro, indicated a clear inhibitory effect on spontaneous contractions at concentrations of 10-8–10-5 M. This effect was dose-dependent. Axons found in association with the cryptonephridial system on the hindgut might be involved in the control of diuresis although we have not tested this possibility experimentally.
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  • 185
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    Cell & tissue research 274 (1993), S. 115-125 
    ISSN: 1432-0878
    Keywords: Autonomic innervation ; Immunohistochemistry ; Intestine, large ; Myenteric plexus ; Neurons ; Neuropeptide colocalization ; Bufo marinus (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of intrinsic enteric neurons and extrinsic autonomic and sensory neurons in the large intestine of the toad, Bufo marinus, was examined using immunohistochemistry and glyoxylic acid-induced fluoresecence. Three populations of extrinsic nerves were found: unipolar neurons with morphology and location typical of parasympathetic postganglionic neurons containing immunoreactivity to galanin, somatostatin and 5-hydroxytryptamine were present in longitudinally running nerve trunks in the posterior large intestine and projected to the muscle layers and myenteric plexus throughout the large intestine. Sympathetic adrenergic fibres supplied a dense innervation to the circular muscle layer, myenteric plexus and blood vessels. Axons containing colocalized calcitonin gene-related peptide immunoractivity and substance P immunoreactivity distributed to all layers of the large intestine and are thought to be axons of primary afferent neurons. Five populations of enteric neurons were found. These contained immunoreactivity to vasoactive intestinal peptide, which distributed to all layers of the large intestine; galanin/vasoactive intestinal peptide, which projected to the submucosa and mucosa; calcitonin gene-related peptide/vasoactive intestinal peptide, which supplied the circular muscle, submucosa and mucosa; galanin, which projected to the submucosa and mucosa; and enkephalin, which supplied the circular muscle layer.
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  • 186
    ISSN: 1432-0878
    Keywords: Serotonin (5-HT) ; Neurohemal systems ; Immunohistochemistry ; Electron microscopy ; Targeted release ; Leptinotarsa decemlineata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We analyzed the anatomy of two diffuse neurohemal systems for serotonin in the head of the Colorado potato beetle Leptinotarsa decemlineata by means of immunohistochemistry. One system is formed by axons from two bilateral pairs of neurons in the frontal margin of the suboesophageal ganglion that enter the ipsilateral mandibular nerve, emerge from this nerve at some distance from the suboesophageal ganglion, and cover all branches of the mandibular nerve with a dense plexus of immunoreactive axon swellings. The other system is formed by axons from two large neurons in the frontal ganglion that enter the ipsilateral frontal connectives, emerge from these connectives, and form a network of axon swellings on the labroforntal, pharyngeal, and antennal nerves and on the surface of the frontal ganglion. Immunohistochemical electron microscopy demonstrated that the axon swellings are located outside the neural sheaths of the nerves and hence in close contact with the hemolymph. We therefore suggest that these plexuses represent extensive neurohemal systems for serotonin. Most immunoreactive terminals are in direct contact with the hemolymph, and other terminals are closely associated with the muscles of the mandibles, labrum, and anterior pharynx, as well as with the salivary glands, indicating that these organs are under serotoninergic control.
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  • 187
    ISSN: 1615-2573
    Keywords: Plasminogen activator inhibitor-1 (PAI-1) ; Immunohistochemistry ; Coronary atherosclerosis ; Intima ; Acute myocardial infarction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Immunohistochemical localization of plasminogen activator inhibitor-1 (PAI-1) was studied using the streptavidin-biotin method in human atherosclerotic coronary arteries. The patients (one male and two females), whose ages ranged from 61 to 78 years, died of anteroseptal acute myocardial infarction without having received any thrombolytic therapy. PAI-1 immunoreactivities (IRs) were mainly detected in the endothelial cells, smooth muscle cells, and collagen fibers of the coronary arterial intima and not in thrombi. Remarkable immunohistochemical staining was seen in intimal collagen fibers. In one patient, intimal PAI-1 IRs partly bordered a thrombus and surrounded a large atheroma rich in cholesterol crystals. Our results suggest that PAI-1 is present in both cellular and extracellular components of human coronary atherosclerotic lesions.
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  • 188
    ISSN: 1573-0646
    Keywords: arabinosyl-5-azacytidine ; cerebrospinal fluid ; pharmacokinetics ; toxicology ; nonhuman primate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Arabinosyl-5-azacytosine (AAC), a new nucleoside antimetabolite, is broadly active in preclinical tumor screening evaluations. To assess the potential for intrathecal use of this drug, we studied the toxicity and pharmacokinetics of intrathecal and intraventricular administration in nonhuman primates. Four adult male rhesus monkeys were given single 10 mg intrathecal (n=1) or intraventricular (n=3) doses of AAC to determine its acute toxicity and pharmacokinetic parameters. An additional 3 animals were given four weekly 10 mg intrathecal doses to assess the systemic and neurologic toxicity associated with chronic administration. Disappearance from the cerebrospinal fluid (CSF) was biexponential, and CSF clearance was 0.2 ml/min, which exceeds the rate of CSF bulk flow by 5-fold. The peak CSF concentration and area under the concentrationx time curve achieved with the intraventricular administration of 10 mg were one hundred, and fifty fold greater, respectively, than those achieved after an intravenous dose of 200 mg/kg (1500–2400 mg) in prior experiments. No clinically evident neurotoxicity was observed in either the single or the weekly × 4 dose groups. A slight, transient CSF pleocytosis and increased CSF protein was observed. Systemic toxicity was limited to one animal in the weekly × 4 dose group who demonstrated a mild and transient decrease in his peripheral leukocyte count unassociated with a change in his hematocrit or platelet count. These studies in nonhuman primates demonstrate a clear pharmacokinetic advantage for intrathecal vs systemic administration of AAC. This is demonstrated by a 50-fold greater CSF drug exposure with an intrathecal or intraventricular dose 1/200th of that which can be given systemically. Intrathecal AAC was found to be safe on a weekly dosing schedule. On the basis of these results, human trials evaluating intrathecal AAC are planned.
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  • 189
    ISSN: 1573-0646
    Keywords: phase I ; dextran-conjugated doxorubicin ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Coupling of anthracyclines to high-molecular-weight carriers may alter drug disposition and improve antitumor effects. We have performed a clinical phase I trial of doxorubicin coupled to dextran (70000 m.w.). The drug was administered as single dose i.v. every 21–28 days. Thirteen patients have received a total of 24 courses (median 2; range 1–3). At the starting dose of 40 mg/m2 doxorubicin equivalent (DOXeq), WHO grade IV thrombocytopenia was noted in 2/2 patients. WHO grade IV hepatotoxicity and WHO grade III cardiotoxicity were noted in a patient with preexisting heart disease. Five patients were treated with 12.5 mg/m2 DOXeq. Maximal toxicity at this dose level was WHO grade III thrombocytopenia and local phlebitis (WHO grade II) in 1/5 patients, elevation of alkaline phosphatase (WHO grade III) and WHO grade III vomiting in another patient. Subsequently, five patients received 20 mg/m2 DOXeq. Hepatotoxicity was noted in 5/5 patients (1 × WHO grade IV, 1 × WHO grade III). Thrombocytopenia was noted in 3/5 patients (1 × WHO grade IV, 2 × WHO grade III). At 12.5 mg/m2 DOXeq, a patient diagnosed with a malignant fibrous histiocytoma had stable disease for 4 months. Pharmacokinetic analyses of total and free doxorubicin were performed in plasma and urine. The maximum peak plasma concentration (ppc) for total DOX was 12.3 μg/ml at 40 mg/m2 DOXeq. The area under the plasma concentration time curve (AUC) ranged from 28.83–80.21 μg/ml*h with dose-dependent elimination half lives (t1/2α: 0.02–0.87 h;1/2β: 2.69–11.58 h;1/2γ: 41.44–136.58 h). We conclude that the maximal tolerated dose (MTD) of AD-70 using this schedule is 40 mg/m2 DOXeq. The recommended dose for clinical phase II studies is 12.5 mg/m2 DOXeq.
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  • 190
    ISSN: 1573-0646
    Keywords: chloroquinoxaline sulfonamide ; toxicity ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Chloroquinoxaline sulfonamide (CQS) has been developed to the clinical trial stage based on its activity in the Human Tumor Colony Forming Assay (HTCFA). In the HTCFA, CQS demonstrated inhibition of colony formation against breast, lung, melanoma and ovarian carcinomas. The mechanism of action of CQS is unknown. It does not appear to inhibit folate metabolism as does the structurally similar sulfaquinoxaline. Preclinical toxicology studies in dogs and rats have shown that CQS is toxic to lymphoid organs, bone marrow, gastrointestinal tract, pancreas, CNS, adrenal glands and testes. Toxicity was generally reversible with the exception of testicular atrophy in dogs and rats which occurred late and was not reversible within the study time frame. The pharmacokinetic data indicate that CQS binds to serum proteins in a dose and species specific manner. Terminal half-lives appear to vary between species from 60 hours in mice, 15 hours in rats, and 45–132 hours in dogs. Preliminary data indicate a longer terminal half-life in humans. Two phase I trials are ongoing using a 60 min infusion schedule once every 28 days. The starting dose for each trial was 18 mg/m2.
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  • 191
    ISSN: 1573-0646
    Keywords: piroxantrone ; pharmacokinetics ; cerebrospinal fluid ; Rhesus monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Piroxantrone is an anthrapyrazole derivative with broad anti-tumor activityin vitro and less cardiac toxicity than the anthracyclines. The metabolic pathways and central nervous system penetration of piroxantrone have not been determined. In this study we examined the pharmacokinetic behavior of piroxantrone in plasma and cerebrospinal fluid in a non-human primate model. In addition, a urinary metabolite of piroxantrone was isolated and its cytotoxicity evaluatedin vitro. The disappearance of piroxantrone from plasma after an intravenous dose of 150 mg/m2 given over 60 minutes was biexponential with mean t1/2 alpha of 1.0 minutes and a mean t1/2 beta of 180 minutes. The mean area under the curve was 220 ΜM·min and the clearance was 1420 ml/min/m2. Piroxantrone was not detectable in the cerebrospinal fluid. Piroxantrone and three other compounds not present in pre-treatment samples were detected in urine. The major urinary metabolite was isolated. Its cytotoxicity against MOLT-4 cellsin vitro was at least one log less than that of piroxantrone. In addition, one of the other compounds detected in urine was determined to be a glucuronide conjugation product of the major metabolite. The results of this study may be useful in the interpretation of the activity and toxicity of piroxantrone in clinical trials.
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  • 192
    ISSN: 1573-0646
    Keywords: anthrapyrazole ; DUP-937 ; phase I ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary DUP-937 is a new anthrapyrazole intercalator that inhibits DNA synthesis. A phase I trial was conducted in which DUP-937 was given in an intravenous bolus weekly for 3 weeks. Cycles were repeated every 5 weeks. Twenty men and 13 women with median ECOG performance status of 1 completed 74 cycles. The starting dose was 0.55 mg/m2/week and doses were escalated to 16 mg/m2/week. Non-hematological toxicity was generally mild or moderate and consisted mainly of gastro-intestinal effects, fatigue, alopecia and local-reactions. Grade 3 neutropenia was first documented at 7.36 mg/m2 and became more common at higher dose levels. Three of four patients had ≥ grade 3 neutropenia at the 16 mg/m2 dose level. Thrombocytopenia was minimal. The dose-limiting toxicity was neutropenia and the maximum tolerated dose was 16 mg/m2 weekly for 3 weeks. Mean area under the curve (AUC) values increased with dose. Linear pharmacokinetics were observed as total body clearance (CLtb), half-life (t1/2) and volume of distribution (Vss) did not change with increasing doses. One partial remission in a patient with prostate carcinoma was documented.
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  • 193
    ISSN: 1573-7241
    Keywords: verapamil sustained release ; antihypertensive effect ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 194
    ISSN: 1573-7241
    Keywords: propranolol ; pharmacokinetics ; nicardipine ; nifedipine ; BAY-K-8644 ; rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine the effect of dihydropyridines on the metabolism of propranolol, we studied the effects of a single oral dose of nicardipine, nifedipine, and BAY-K-8644 on the pharmacokinetics of propranolol in male Wistar rats fitted with a catheter in the jugularis vein. Oral propranolol (15 mg/kg and 1.5 mg/kg) and intravenous propranolol (1.5 mg/kg) were administered either alone or together with oral nicardipine (2.5 mg/kg). Oral propranolol (15 mg/kg) was administered with oral nifedipine (1.5 mg/kg) and with oral BAY-K-8644 (1.5 mg/kg). Nicardipine increased significantly the AUC and Cmax of oral propranolol (1.5 mg/kg and 15 mg/kg). However, the plasma concentration time curve of intravenous propranolol (1.5 mg/kg) was unaffected. Nifedipine also significantly increased the AUC and Cmax of oral propranolol (15 mg/kg), whereas with BAY-K-8644 there was only a slight increase in the bioavailability of oral propranolol (15 mg/kg). The results indicate that the dihydropyridine calcium antagonists decrease the metabolism of propranolol as a result of a decrease in first-pass clearance. Although an interaction at the level of cytochrome P450 may also be involved, the results of the present study suggest that the inhibitory effect can be largely attributed to changes in liver blood flow.
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  • 195
    ISSN: 1573-7446
    Keywords: buffalo ; disposition ; dose ; kanamycin ; pharmacokinetics ; serum ; urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The disposition kinetics and appropriate dosage regimen for kanamycin were investigated in buffalo calves following a single intravenous dose of 10 mg/kg body weight. The distribution and elimination half-lives were 0.12±0.01 h and 1.94±0.11 h, respectively. The apparent volume of distribution and total body clearance were 0.2±0.01 L/kg and 92.9±3.69 ml/kg/h, respectively. About 74% of the administered dose was excreted in urine in 24 h. A suitable dosage regimen for the intravenous administration of kanamycin was also calculated.
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  • 196
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    Veterinary research communications 17 (1993), S. 295-303 
    ISSN: 1573-7446
    Keywords: cows ; intramuscular ; intravenous ; lactation ; milk ; pharmacokinetics ; serum ; thiamphenicol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The pharmacokinetics of thiamphenicol were studied after intravenous and intramuscular administration of 25 mg/kg body weight in lactating cows. Distribution (t 1/2α) and elimination (t 1/2β) half-lives of 6.10±1.39 min and 1.60±0.30 h, respectively, were obtained after intravenous administration. The body clearance was 3.9±0.077 ml/kg per min and the apparent volume of distribution was 1220.79±256.67 ml/kg. The rate at which thiamphenicol appeared in the milk, as indicated by the penetration half-life (t 1/2P) (serum to quarters), was found to be 36.89±11.14 min. The equivalent elimination half-life (t 1/2E) (quarters to serum) from the milk was 3.62±1.06 h and the peak thiamphenicol concentration in the milk was 23.09±3.42 µg/ml at 2.5±0.32 h. After intramuscular injection, the elimination half-life was 2.2±0.40 h, the absorption half-life was 4.02±1.72 min and the peak concentration in the serum was 30.90±5.24 µg/ml at 23±8.4 min. The bioavailability after intramuscular administration approached 100%. The penetration half-life was 50.59±6.87 min, the elimination half-life was 5.91±4.97 h and the mean peak concentration in the milk was 17.37±2.20 µg/ml at 3.4±0.22 h.
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  • 197
    ISSN: 1573-7446
    Keywords: benzydamine ; bioavailability ; cattle ; milk ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Five lactating cows were given benzydamine hydrochloride by rapid intravenous (0.45 mg/kg) and by intramuscular (0.45 and 1.2 mg/kg) injection in a crossover design. The bioavailability, pharmacokinetic parameters and excretion in milk of benzydamine were evaluated. After intravenous administration, the disposition kinetics of benzydamine was best described using a two-compartment open model. Drug disposition and elimination were fast (t 1/2α: 11.13±3.76 min;t 1/2β: 71.98±24.75 min; MRT 70.69±11.97 min). Benzydamine was widely distributed in the body fluids and tissues (V d(area): 3.549±1.301 L/kg) and characterized by a high value for body clearance (33.00±5.54 ml/kg per min). After intramuscular administration the serum concentration-time curves fitted a one-compartment open model. Following a dose of 0.45 mg/kg, theC max value was 38.13±4.2 ng/ml at at max of 67.13±4.00 min; MAT and MRT were 207.33±22.64 min and 278.01±12.22 min, respectively. Benzydamine bioavailability was very high (92.07%±7.08%). An increased intramuscular dose (1.2 mg/kg) resulted in longer serum persistence (MRT 420.34±86.39 min) of the drug, which was also detectable in milk samples collected from both the first and second milking after treatment.
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  • 198
    ISSN: 1573-7446
    Keywords: β-agonists ; clenbuterol ; immunoassay ; pharmacokinetics ; residues ; ultrasound ; withdrawal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The detection of the illegal use of clenbuterol (CBL) as a growth promoter has relied on detecting residual concentrations of the drug in body fluids or tissues. Analysis of retinal extracts has recently been shown to considerably extend the detection period following withdrawal. The withdrawal periods required to eliminate residues from the liver and retina were investigated by medicating 20 cattle with CBL for 30 days; 6 control animals remained unmedicated. Residual concentrations were monitored throughout this period and for the subsequent 140 days. Concurrent changes in muscle areas and backfat thicknesses were recorded by ultrasound. CBL was detectable in liver up to the 56th day of withdrawal (0.35 ng/g, SD=0.5), but retinal concentrations remained well above detectable concentrations throughout the withdrawal period (22.5 ng/g, SD=6.5). There were small gains (3–4%) in the muscle areas of treated cattle during medication as compared to controls (p〉0.05). These comparative gains remained during withdrawal. Backfat thicknesses in treated animals were 40% lower than in controls at the end of medication (p〈0.01). However, by 70 days after withdrawal this difference had disappeared (p〉0.05) owing to accelerated fat deposition in the treated group. The retina has been shown to be a highly effective target matrix for detecting CBL administration after long withdrawal periods.
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  • 199
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    Veterinary research communications 17 (1993), S. 129-136 
    ISSN: 1573-7446
    Keywords: calves ; carboxyprimaquine ; pharmacokinetics ; plasma ; primaquine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The pharmacokinetics of primaquine was studied in calves of 180–300 kg live weight. Primaquine was injected at 0.29 mg/kg (0.51 mg/kg as primaquine diphosphate) intravenously (IV) or subcutaneously (SC) and the plasma concentrations of primaquine and its metabolite carboxyprimaquine were determined by high-performance liquid chromatography. The extrapolated concentration of primaquine at zero time after IV administration was 0.50±0.48 µg/ml (mean ±SD) which decreased with an elimination half-life of 0.16±0.07 h. Primaquine was rapidly converted to carboxyprimaquine after either route of administration. The peak concentration of carboxyprimaquine was 0.50±0.08 µg/ml at 1.67±0.15 h after IV administration. The corresponding value was 0.47±0.07 µg/ml at 5.05±1.20 h after SC administration. The elimination half-lives of carboxyprimaquine after IV and SC administration were 15.06±0.99 and 12.26±3.06 h, respectively. The areas under the concentration-time curve for carboxyprimaquine were similar following either IV or SC administration of primaquine; the values were 11.85±2.62 µg.h/ml after the former and 10.95±2.65 µg.h/ml after the latter. The mean area under the concentration-time curve for primaquine was less than 0.1 µg.h/ml after either route of administration.
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  • 200
    ISSN: 1573-904X
    Keywords: liposomes ; methylprednisolone ; pharmacokinetics ; tissue distribution ; pharmacodynamics ; glucocorticoid receptors ; drug delivery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A liposomal formulation of methylprednisolone (L-MPL) was developed to improve localization of this immunosuppressant in lymphatic tissues. Liposomes containing MPL were formulated from a mixture of phosphatydylcholine and phosphatydylglycerol (molar ratio, 9:1) and sized by extrusion through a 0.1-µm membrane. Male Sprague–Dawley rats received a bolus dose of 2 mg/kg of L-MPL or free MPL in solution (control). Samples of blood, spleen, liver, thymus, and bone marrow were collected at intervals over a 66-hr period. Concentrations of MPL in plasma and organs and free cytosolic glucocorticoid receptors (GCR) in spleen and liver were determined. The plasma MPL profiles for free and L-MPL were bi- and triexponential. Although the alpha phase kinetics of both dosage forms were similar, L-MPL showed a substantially slower elimination phase than did free drug. Incorporation of MPL into liposomes caused the following increases: terminal half-life, from 0.48 (MPL) to 30.13 hr (L-MPL); MRT, from 0.42 to 11.95 hr, V ss, from 2.10 to 21.87 L/kg; and AUC, from 339 to 1093 ng · hr/mL. Uptake of liposomes enhanced significantly the delivery of drug to lymphatic tissues and liver; AUC tissue:plasma ratios for spleen increased 77-fold; for liver, 9-fold; and for thymus, 27-fold. The duration of GCR occupancy was extended 10-fold in spleen and 13-fold in liver by the liposomal formulation. Lymphatic tissue selectivity and extended receptor binding of liposome-delivered MPL offer promise for enhanced immunosuppression.
    Type of Medium: Electronic Resource
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