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  • 1
    Electronic Resource
    Electronic Resource
    Mutant genes of cytochrome P-450IID6, glutathione S-transferase class Mu, and arylamine N-acetyltransferase in lung cancer patients (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. 307-319 
    Details
    ISSN: 1432-1440
    Keywords: Pharmacogenetics ; Cancer epidemiology ; Lung cancer ; Polymerase chain reaction ; Restriction fragment length polymorphism ; Cytochrome P-45011136 ; Glutathione S-transferase ; Arylamine N-acetyltransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Epidemiological studies suggested a protective effect of certain phenotypes of polymorphic foreign-compound-metabolizing enzymes in some types of cancer. Poor metabolizers (PM) of debrisoquine 4-hydroxylase (cytochrome P-450IID6, CYP2D6) were found to be underrepresented among patients with lung cancer. Recent advances in molecular genetic characterization of CYP2D6, glutathione S-transferase (GST) class Mu, and arylamine N-acetyltransferase enabled genotypical determination of mutant alleles in lung cancer patients. Restriction fragment length polymorphism (RFLP) with a cDNA gene probe of CYP2D6 was analyzed in 79 lung cancer patients who were phenotyped with debrisoquine. Mutant alleles were detected by allele-specific polymerase chain reaction (PCR). In the same individuals, genotype of GST class Mu was analyzed by PCR and correlated with ex vivo activity of glutathione conjugation towards trans-stilbene oxide. RFLP patterns allowed discrimination between the slow and fast genotype of N-acetyltransferase as well as the heterozygotes. Three phenotypical PMs of debrisoquine (3.8%) were confirmed by PCR and RFLP. No PM could be unambiguously recognized only by RFLP patterns. The PMs were characterized by PCR and RFLP as carriers of the 29B/29B (n=1), 29A/29B (n=1), and 29A/44 (n = 1) mutant alleles. Higher debrisoquine hydroxylase activities were found in the homozygous EMs, who possess two active genes, as compared to heterozygous EMs, who have only one active gene. The patients with phenotypically impaired GST Mu activity were confirmed as such by PCR. A complete correspondence between phenotyping of N-acetyltransferase (with caffeine) and genotyping was found. The new genetic techniques proved to be powerful tools for molecular-epidemiological studies aimed at establishing host factors of cancer susceptibility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00184667
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  • 2
    Electronic Resource
    Electronic Resource
    Polymorphisms in the human CYP1A1 gene as susceptibility factors for lung cancer: exon-7 mutation (4889 A to G), and a T to C mutation in the 3′-flanking region (1994)
    Springer
    Journal of molecular medicine 72 (1994), S. 240-248 
    Details
    ISSN: 1432-1440
    Keywords: Cytochrome P-450 ; CYP1A1 ; Polymorphism ; Lung cancer ; Polymerase chain reaction ; Cancer epidemiology ; Risk factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Genetic differences in the metabolism of carcinogens may codetermine individual predisposition to cancer. Cytochrome P-4501A1 (CYP1A1) metabolically activates precarcinogens in cigarette smoke, such as benzo(a)pyrene, which is also an inducer of CYP1A1. Two point mutations have been reported, m1 in the 3′-flanking region (6235T to C), and m2 within exon 7 (4889A to G), the latter leading to an isoleucine to valine exchange. In the Japanese population ml and m2 are correlated with lung cancer, suggesting an increased susceptibility to cigarette smoking related lung cancer. We studied 142 lung cancer and 171 reference patients in an ethnically homogeneous German group for m1 and m2 mutations by restriction fragment length polymorphism and allele-specific polymerase chain reaction, respectively. No statistically significant difference was found in the distribution of m1 alleles between lung cancer and controls; the frequency was 8.5% and 7.3% of the alleles, respectively (odds ratio = 1.17). A trend to an overrepresentation of ml alleles was observed among 52 squamous cell carcinoma patients (odds ratio = 1.65). In contrast, the frequency of m2 alleles in lung cancer patients was twofold higher (6.7%) than in the reference group (3.2%; odds ratio = 2.16; 95% confidence limits 0.96–5.11, P = 0.033); the odds ratio of m2 alleles in squamous cell carcinoma was 2.51 (95% confidence limits 0.85–7.05, P = 0.05). There was a close genetic linkage of m2 to m1 (10 of 11 reference patients), but a significantly higher number of cancer patients showed no linkage compared to the controls (odds ratio = 8.89, 95% confidence limits 0.83–433, P = 0.04). Thus no association was found between presence of ml alleles and lung cancer, but, in contrast, m2 alleles proved as a hereditary risk factor, especially if not linked with m1 alleles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189321
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  • 3
    Electronic Resource
    Electronic Resource
    Evaluation ofin vivo parameters of drug metabolizing enzyme activity in man after administration of clemastine, phenobarbital or placebo (1975)
    Springer
    European journal of clinical pharmacology 8 (1975), S. 327-336 
    Details
    ISSN: 1432-1041
    Keywords: Glucaric acid ; aminopyrine half life ; gamma-glutamyl-transpeptidase ; 6β-hydroxycortisol ; enzyme induction ; drug metabolism in man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The 24 h urinary excretion of 6β-hydroxycortisol and D-glucaric acid, the plasma half-lives and total clearances of aminopyrine, and serum gamma-glutamyl-transpeptidase activity have been measured in nineteen healthy male volunteers. The study was done double blind and was conducted as a test of induction of microsomal drug metabolizing enzymes during and after daily doses of 6 mg clemastine, 300 mg phenobarbital or a placebo. The urinary excretion of 6β-hydroxycortisol and D-glucaric acid was significantly increased in the phenobarbital group, the standard for induction. No changes were observed after treatment with clemastine or placebo. Phenobarbital also reduced the half life of aminopyrine, but it was not affected by clemastine or placebo. Gamma-glutamyl-transpeptidase activity increased only in the phenobarbital group. The elimination constant k2 of aminopyrine and the excretion of glucaric acid in the pre-medication period were correlated (p〈0.05). The results indicate that the tests were of diagnostic value in determination of microsomal enzyme induction by phenobarbital. Failure to observe similar changes after treatment with clemastine imply failure of induction of this activity under the experimental conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562658
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  • 4
    Electronic Resource
    Electronic Resource
    Quantitative determination by HPLC of urinary 6β-hydroxycortisol, an indicator of enzyme induction by rifampicin and antiepileptic drugs (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 63-71 
    Details
    ISSN: 1432-1041
    Keywords: 6beta-hydroxycortisol ; rifampicin ; cortisol metabolism ; high performance ; liquid chromatography ; urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A method for determination of 6β-hydroxycortisol in urine by means of high performance liquid chromatography is described. After extraction of 10–30 ml aliquots of urine with ethylacetate, separation is accomplished on a silica gel column (30 cm, Lichrosorb Si 100) with a special two-phase four-component eluent of methylene chloride, n-hexane, ethanol and water. Complete separation of α- andβ-isomers requires 15 to 20 min. For routine determinations precolumn cleaning by backflush permits injections of samples at minimum time intervals. For quantitative determinations, each injection should contain at least 0.05–0.5 µg of 6β-hydroxycortisol, depending on the detector employed. The mean excretion rate in healthy male adults (26–40 years) was 273 µg/day (SD=74.5; n=12). In patients on long term mono-therapy with rifampicin, 6β-hydroxycortisol excretion had risen fourfold (1166 µg/d; SEM=248; n=7), paralleling the known enzyme-inducing effect of rifampicin. The relatively smaller increase to 498 µg/d observed in patients receiving triple therapy with rifampicin, isoniazid and ethambutol points to possible inhibition by isoniazid. The greatest stimulation of 6β-hydroxycortisol excretion (2352 µg/d) was found in patients receiving antiepileptic therapy (phenytoin and/or carbamazepine and other drugs). The HPLC technique for 6β-hydroxycortisol proved to be a tool routinely applicable to non-invasive evaluation of drug metabolizing enzyme activity in man.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00644969
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  • 5
    Electronic Resource
    Electronic Resource
    Kinetics of hexobarbital and dipyrone in critical care patients receiving high-dose pentobarbital (1987)
    Springer
    European journal of clinical pharmacology 32 (1987), S. 273-277 
    Details
    ISSN: 1432-1041
    Keywords: pentobarbital ; hexobarbital ; dipyrone ; intensive care ; D-glucaric acid ; pharmacokinetics ; drug interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of pentobarbital treatment in a mean dose of 30 mg/kg/day on the clearance of hexobarbital (Evipan) and dipyrone (Novalgin) has been evaluated in critical care patients receiving a large number of drugs as comedication. Eleven patients treated with pentobarbital showed a hexobarbital half-life of 2.79 h and a total plasma clearance of 9.80 ml·min−1·kg−1 as compared to 10 patients without pentobarbital administration in whom there was a significantly longer half life (6.92 h) and lower clearance (2.97 ml·min−1·kg−1). The kinetics of hexobarbital were correlated with the urinary excretion of D-glucaric acid, a non-invasive parameter of drug metabolising activity. In 10 patients on pentobarbital, the total plasma clearance of N-4-methylaminoantipyrine, the active form of dipyrone, did not differ from that in 8 patients not receiving pentobarbital. As drug kinetics show great variability in these patients, it is difficult to discriminate enzyme induction from other mechanisms, for example competitive inhibition or changes in volume of distribution. In the presence of pentobarbital, however, induction of drug metabolising enzymes should be considered as a possible reason for the higher clearance of hexobarbital.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00607575
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  • 6
    Electronic Resource
    Electronic Resource
    Pharmacokinetic interaction between cyclosporin and diltiazem (1990)
    Springer
    European journal of clinical pharmacology 38 (1990), S. 237-242 
    Details
    ISSN: 1432-1041
    Keywords: cyclosporin A ; diltiazem ; pharmacokinetics ; kidney transplantation ; drug metabolism ; cytochrome P-450 ; drug interactions ; human liver microsomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Previous reports have indicated that administration of the calcium antagonist diltiazem results in major changes in the pharmacokinetics of cyclosporin A (CyA). A new clinical trial was undertaken in 22 renal transplant patients receiving a constant dose of cyclosporin to further explore this interaction. Coadministration of diltiazem for one week produced an increase in the blood concentration of CyA and its metabolites 17 and 18 in almost all patients, but no increase in CyA metabolites 1 and 21. The mean whole blood CyA trough level determined by HPLC rose from 117 ng·ml−1 to 170 ng·ml−1 after one week on diltiazem, and the mean trough level of metabolite 17 rose similarly from 184 ng·ml−1 before to 336 ng·ml−1. Based on experiments with microsomes from human liver the effect of diltiazem was due to noncompetitve inhibition of CyA-metabolism by diltiazem, and the increased concentration of metabolite 17 might have been due to stronger inhibition of its secondary metabolism steps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315023
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  • 7
    Electronic Resource
    Electronic Resource
    The kinetics of metamizol and its metabolites in critical-care patients with acute renal dysfunction (1993)
    Springer
    European journal of clinical pharmacology 45 (1993), S. 445-450 
    Details
    ISSN: 1432-1041
    Keywords: Metamizol ; Acute renal failure ; Sepsis ; intensive care patients ; drug metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the clearance of monomethylaminoantipyrine (MMAAP), the pharmacologically active form of metamizol, in 46 patients in surgical intensive care with different degrees of renal dysfunction. In 23 patients without any renal impairment, mean clearance was 2.8 ml·min−1·kg−1. Twentyone patients with acute renal impairment had a significantly reduced clearance of MMAAP (0.83 ml·min−1·kg−1). There was also reduced clearance in four patients with septic shock (1.0 ml·min−1·kg−1). Kinetics of the metabolites of MMAAP (N-formylaminoantipyrine (FAAP), aminoantipyrine (AAP), and its secondary product N-acetylaminoantipyrine (AcAAP)) were calculated. FAAP and AcAAP showed delayed invasion, which can be explained by reduced hepatic metabolic activity. The product of N-demethylation, AAP, was not significantly altered. The delayed elimination of monomethylaminoantipyrine can be explained by reduced hepatic function in parallel with acute renal failure due to disturbed cardiovascular function caused by septic shock. This may also lead to disturbed hepatic macro- and microperfusion associated with altered oxygen supply and oxygen consumption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315516
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  • 8
    Electronic Resource
    Electronic Resource
    Antipyrine metabolite formation and excretion in patients with chronic renal failure (1985)
    Springer
    European journal of clinical pharmacology 28 (1985), S. 589-595 
    Details
    ISSN: 1432-1041
    Keywords: antipyrine ; chronic renal failure ; drug metabolism ; metabolism ; cumulation ; renal excretion ; pharmacokinetics ; clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In the present study the influence of chronic renal insufficiency on antipyrine clearance, metabolite formation and excretion was investigated in 8 patients. After oral administration of antipyrine, the parent compound, its metabolites and their conjugates were assayed in plasma and urine. Besides the parent drug, 3-hydroxymethylantipyrine (HMA) was present in plasma in the free and conjugated forms, whereas 4-hydroxyantipyrine (OHA) and norantipyrine (NORA) were found only in the conjugated form. The same was true for urine. The plasma concentrations of these metabolites are too low to be measured in subjects with normal renal function. Plasma antipyrine clearance in the patients was in the same range as in healthy subjects. Investigation of metabolite kinetics, however, revealed that the rate of formation of NORA was preferentially decreased, whereas that of OHA and HMA were unaltered. Renal clearance of the metabolites of antipyrine was severely impaired in patients with renal insufficiency, and the resulting accumulation made it possible for the first-time to measure the antipyrine metabolites in plasma. Mean residence times of metabolites were longer than that of the parent compound. Renal clearances of the conjugates were correlated with the creatinine clearance, but were somewhat higher. Renal clearance of free HMA was lower and was also correlated with creatinine clearance. The mean clearance for glucuronidation of HMA was 93.1 ml/min. The results suggest that in healthy subjects Phase I metabolism is the rate-limiting step in the elimination of antipyrine, which is essential for its application as a model drug in metabolism studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00544072
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  • 9
    Electronic Resource
    Electronic Resource
    Urinary excretion ofD-glucaric acid, an indicator of drug metabolizing enzyme activity, in patients with impaired renal function (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 255-261 
    Details
    ISSN: 1432-1041
    Keywords: D-glucaric acid ; renal insufficiency ; phenobarbital ; dipyrone ; cortisol ; enzyme induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The urinary excretion rate ofD-glucaric acid, an in vivo parameter of the activity of drug metabolizing enzymes, has been determined in patients with chronic renal insufficiency (glomerular filtration rate 4.5–80 ml/min/1.73 m2). The mean value of 22.3 µmoles/d (SD 7.2; n 28) was almost identical to that of healthy controls (22.1 µmoles/d, SD 7.3; n 22). Thus, no inhibitory or enhancing effect of renal insufficiency could be detected. The ability of this parameter to indicate alterations in the activity of hepatic drug metabolism, even in patients with renal insufficiency, was demonstrated by the increased excretion rate of glucaric acid (107 µmoles/d, SD 43.5; n 8; p〈0.001) after treatment for 7 days with the enzyme inducer phenobarbital. No significant correlation was found between glucaric acid excretion and sex, age, body weight or body surface in 50 patients. Glucaric acid excretion, therefore, should not be related to the creatinine content of urine samples, since creatinine excretion decreases with severity of renal insufficiency and varies with sex, age, body weight and many other conditions. A single dose of dipyrone (Novalgin®), a further in vivo indicator of drug metabolism, increased glucaric acid excretion on the same day, but no interference was found after a single dose of cortisol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00563008
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  • 10
    Electronic Resource
    Electronic Resource
    Evaluation of proposed sulphoxidation pathways of carbocysteine in man by HPLC quantification (1991)
    Springer
    European journal of clinical pharmacology 40 (1991), S. 387-392 
    Details
    ISSN: 1432-1041
    Keywords: Carbocysteine ; pharmacogenetics ; drug metabolism ; sulphoxidation ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A quantitative study has been made of the metabolism of S-carboxymethyl-L-cysteine (CMC) and its sulphoxides in volunteers by HPLC. Precolumn derivatization was applied prior to gradient reversed phase HPLC separation and fluorescence detection. For CMC and its metabolites containing a primary amino group the reagent 9-fluorenylmethylchloroformate was used. The other metabolites of CMC were derivatized at their carboxylic group with 1-pyrenyldiazomethane to give stable fluorescent products. Urine samples were collected for 8 h after oral administration of 1.125 g CMC to 33 healthy volunteers. Elimination of CMC in urine as sulphoxides did not account for more than 1% of the dose in any of the volunteers. Thus, CMC-sulphoxide metabolites are not quantitatively important. Recovery of the original substance in 8-hour urines ranged from 10 to 30% and a further 2 to 20% was recovered as the metabolite thiodiglycolic acid. Oral doses of 0.19, 1.125, and 2.25 g CMC in a second group of 12 healthy volunteers did not reveal dose dependence of the urinary excretion of the sulphoxides or of thiodiglycolic acid. Serum concentration-time-curves of CMC, (S)- and (R)-CMC sulphoxide were measured in a group of 9 healthy volunteers. The CMC sulphoxides in serum reached 1.5% of the parent substance after 4 hours. The ratio of CMC to its sulphoxide metabolites was similar in serum and urine. Pharmacogenetic polymorphism of sulphoxidation was not confirmed by the specific HPLC methods used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00265849
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