bluuebunny/crossref_metadata_2025 huggingface dataset:
Oral bioavailability of dihydroartemisinin in Vietnamese volunteers and in patients with falciparum malaria
Authors: Binh Tran Quang , Ilett Kenneth F. , Batty Kevin T. , Davis Timothy M. E. , Hung Nguyen Canh , Powell Shane M. , Thu Le Thi Anh , Van Thien Huynh , Phuöng Hoang Lan , Phuong Vu Duong Bich
Published: March 2003

Aims  To obtain comprehensive bioavailability data for artesunate (ARTS) and its active metabolite dihydroartemisinin (DHA) following their separate oral administration to Vietnamese volunteers and to patients with acute, uncomplicated falciparum malaria.

Methods  Volunteers were randomized to receive either i.v. ARTS (120 mg) followed by oral ARTS (150 mg) 8 h later (Group 1, n = 10), or i.v. ARTS (120 mg) followed by oral DHA (120 mg) 8 h later. Patients, also received oral ARTS (150 mg; Group 3, n = 8) or DHA (120 mg; Group 2, n = 7), in a randomized cross‐over study design. Multiple blood samples were collected after each administration and plasma ARTS and/or DHA concentrations were determined by h.p.l.c. Pharmacokinetic descriptors were obtained from noncompartmental analysis and bioavailability was calculated from AUC data. In the patients, the time to 50% parasite clearance (PCT50) and fever clearance time (FCT) also were measured.

Results  In Group 1 (volunteers), the mean (95% CI) absolute bioavailability of oral ARTS was 80% (62,98%), while in Group 2 (volunteers), the bioavailability of oral DHA was 45% (34,56%). In the patients (Group 3), the bioavailability of oral DHA relative to oral ARTS was 88% (49,127%). The median PCT50 and FCT were 2.3 and 28 h, respectively.

Conclusions  The study shows that the absolute bioavailability of DHA was significantly lower than that for ARTS in healthy volunteers. The bioavailability of ARTS in volunteers was consistent with previous studies in patients with uncomplicated falciparum malaria. The dose‐normalized Cmax and AUC(0,∞) for DHA were significantly greater in patients with falciparum malaria than in healthy volunteers. The high relative bioavailability of DHA in the patients may have been due to lower first‐pass clearance. We conclude that, for the treatment of malaria, DHA is likely to be a suitable oral substitute for ARTS. Based on our mean AUC measurements, it appears that equal doses of DHA and ARTS (mg basis) should give equivalent systemic exposure to bioactive DHA in uncomplicated falciparum malaria.
What knowledge and skills are essential for specialists in Clinical Pharmacology and Therapeutics? Results of a Delphi study
Authors: Mucklow J. C.
Published: March 2003

Aims  To identify the knowledge and skills that should be considered essential for specialists in Clinical Pharmacology and Therapeutics (CPT) with a commitment to the National Health Service (NHS).

Methods  A Delphi study using a sample of current specialists.

Results  Members of the expert panel (20 in all, representative of the Clinical Section membership) identified 78 statements for consideration, in four domains (core of knowledge, therapeutic skills, educative skills, and investigative skills), of which 58 (74.4%) were accepted by more than two‐thirds of respondents. Of these, 35 were knowledge items, whereas 23 were skills (11 therapeutic, 4 educative and 8 investigative). The large majority (79.3%) of these statements were endorsed by at least four out of five panel members.

Conclusions  Despite the varied work patterns and responsibilities of specialists in CPT, it is possible to identify a core of knowledge and skill that most consider essential for the delivery of their commitment to the NHS. The findings will provide NHS Trusts with a clear idea of what they can expect from these specialists, and will act as a checklist for specialists themselves to direct their Continuing Professional Development within the consultant appraisal process. The results also describe a curriculum for continuing education in CPT, which the BPS Clinical Section can use to develop information resources and training opportunities.
The influence of CYP2B6, CYP2C9 and CYP2D6 genotypes on the formation of the potent antioestrogen Z‐4‐hydroxy‐tamoxifen in human liver
Authors: Coller Janet K. , Krebsfaenger Niels , Klein Kathrin , Endrizzi Karin , Wolbold Renzo , Lang Thomas , Nüssler Andreas , Neuhaus Peter , Zanger Ulrich M. , Eichelbaum Michel , Mürdter Thomas E.
Published: March 2003

Aims  To investigate in a large panel of 50 human liver samples the contribution of CYP2C9, CYP2D6, and CYP3A4 to the overall formation of the potent antioestrogen Z‐4‐hydroxy‐tamoxifen, and how various genotypes affect its formation from tamoxifen.

Methods  The formation of Z‐4‐hydroxy‐tamoxifen from 10 µm tamoxifen was studied in human liver microsomes (n=50), characterized for CYP2B6, CYP2C9, CYP2D6 and CYP3A4 expression, and CYP2B6, CYP2C9 and CYP2D6 genotype. The effect of chemical and monoclonal antibody inhibitors, and the formation in supersomes expressing recombinant CYP isoforms was also investigated. Z‐4‐hydroxy‐tamoxifen was quantified using LC‐MS analysis.

Results  Z‐4‐hydroxy‐tamoxifen was formed by supersomes expressing CYP2B6, CYP2C9, CYP2C19 and CYP2D6, but not CYP3A4. In agreement with these data, the mean formation of Z‐4‐hydroxy‐tamoxifen was inhibited 49% by sulphaphenazole (P=0.001), 38% by quinidine (P<0.05) and 13% by monoclonal antibody against CYP2B6 (MAB‐2B6, P<0.05). Furthermore, Z‐4‐hydroxy‐tamoxifen formation significantly correlated with both CYP2C9 expression (rs=0.256, P<0.05) and CYP2D6 expression (rs=0.309, P<0.05). Genotypes of CYP2D6, CYP2B6 and CYP2C9 had an effect on metabolite formation in such a way that samples with two nonfunctional CYP2D6, or two variant CYP2C9 or CYP2B6 alleles, showed lower enzyme activity compared with those with two functional or wild‐type alleles, (5.0 vs 9.9 pmol mg−1 protein min−1, P=0.046, 5.1 vs 9.9 pmol mg−1 protein min−1, P=0.053, and 6.8 vs 9.4 pmol mg−1 protein min−1, P=0.054, respectively). CYP2D6 and CYP2C9 contribute on average 45 and 46%, respectively, to the overall formation of Z‐4‐hydroxy‐tamoxifen.

Conclusions  CYP2B6, CYP2C9 and CYP2D6 genotypes all affected Z‐4‐hydroxy‐tamoxifen formation and can predict individual ability to catalyse this reaction.
Non‐antiarrhythmic drugs prolonging the QT interval:considerable use in seven countries
Authors: De Ponti Fabrizio , Poluzzi Elisabetta , Vaccheri Alberto , Bergman Ulf , Bjerrum Lars , Ferguson John , Frenz Kerry J. , McManus Peter , Schubert Ingrid , Selke Gisbert , Terzis‐Vaslamatzis Georgia , Montanaro Nicola
Published: March 2003

Aims  Many drugs belonging to different therapeutic classes appear to share a potentially fatal side‐effect: ventricular tachyarrhythmias associated with QT prolongation. The aim of this study was to assess the relevance and the magnitude of the problem in seven countries by grouping all nonantiarrhythmic drugs according to the type of evidence on QT prolongation and analysing their sales data.

Methods  We divided all nonantiarrhythmic QT‐prolonging agents into the following categories (in increasing order of clinical relevance): group A, drugs with published clinical or preclinical evidence on QT prolongation or with relevant official warnings; group B, drugs with published clinical or preclinical evidence; group C, drugs with published clinical evidence; group D, drug with published clinical evidence on torsades de pointes or ventricular arrhythmias associated with QT prolongation; group E, drugs belonging to group D with official warnings. We retrieved 1998 sales data from community pharmacies in seven countries (Australia, Denmark, England, Germany, Greece, Italy and Sweden). Data for individual agents were expressed as defined daily doses per 1000 inhabitants per day (DDD/1000/day). Overall use in each country was calculated for each drug group. Groups D and E were considered as the most clinically relevant.

Results  Among the 102 nonantiarrhythmic agents meeting at least one of the inclusion criteria, 33 drugs had sales data ≥1 DDD/1000/day and 71 drugs had a use ≥0.1 DDD/1000/day in at least one country. Among the 37 nonantiarrhythmic agents with published reports of ventricular arrhythmias associated with QT prolongation, 12 compounds had sales data ≥1 DDD/1000/day. Total consumption in each country ranged: from 51.9 to 94.7 DDD/1000/day for group A; from 51.6 to 92.7 DDD/1000/day for group B; from 37.1 to 76.6 DDD/1000/day for group C; from 12.9 to 29.1 DDD/1000/day for group D; and from 5.8 to 15.3 DDD/1000/day for group E.

Conclusions  In spite of wide variations in the sales of individual agents, the overall extent of use of nonantiarrhythmic QT‐prolonging drugs was of the same order of magnitude in all countries. The significant use of drugs belonging to categories D and E should prompt careful risk/benefit assessment of each agent.
Quinidine does not affect the renal clearance of moxonidine
Authors: Wise Stephen D. , Chan Clark , Schaefer Hans G. , He Minxia M. , Pouliquen Isabelle J. , Mitchell Malcolm I.
Published: March 2003

Aims
To test the hypothesis that the renal clearance of moxonidine decreases when dosed with quinidine.

Methods
A randomized, two‐period study was conducted with six healthy, male subjects orally dosed with either 0.2 mg moxonidine alone or 1 h after 400 mg quinidine sulphate. Pharmacokinetic parameters were calculated using a noncompartmental analysis method.

Results
When coadministered, quinidine significantly increased moxonidine AUC and t1/2 by 11% and 15%, respectively, and decreased CL/F by 10% compared with the control dosing. CLR and Aeur were not significantly different. Clinically, both treatments were well tolerated.

Conclusions
Quinidine does not affect the renal clearance of moxonidine. The decrease  in  apparent  total  clearance  of  moxonidine  with  quinidine  coadministration was possibly due to metabolic inhibition, though not likely to be clinically significant.
The effects of St John's wort extract on heart rate variability, cognitive function and quantitative EEG: a comparison with amitriptyline and placebo in healthy men
Authors: Siepmann M. , Krause S. , Joraschky P. , Mück‐Weymann M. , Kirch W.
Published: March 2003

Aims
To compare the effects of multiple dosing with St John's wort (Hypericum perforatum) extract and amitriptyline on heart rate variability, cognitive function and quantitative EEG (qEEG) with placebo in healthy humans.

Methods
A randomized, double‐blind, cross over study of 12 healthy male volunteers. Subjects orally received capsules with 255–285 mg St John's wort extract (900 µg hypericin content), 25 mg amitriptyline and placebo three times daily for periods of 14 days each with at least 14 days between. The doses of amitriptyline and St John's wort extract are comparable with respect to their antidepressant activity. Compliance was confirmed by coadministration of 10 mg of riboflavin with each capsule and detection of urinary vitamin B2 on treatment day 11 with high performance liquid chromatography. Measurements of heart rate variability, psychometric tests and qEEG were performed before start of medication and repeatedly on the last treatment day.

Results
St John's wort extract did not affect heart rate variability (HRV) whereas amitripytline significantly decreased it: the difference in the percentage number of adjacent RR intervals> 50 ms (pNN50) was 8.6 (−2.6, 19.9; mean; 95% confidence interval) between St John's wort extract and placebo and −17.6 (−24.7, −10.4) between amitriptyline and placebo. Neither St John's wort extract nor amitriptyline had an influence on cognitive performance such as choice reaction, psychomotor coordination, short‐term memory and responsiveness to distractive stimuli. Amitriptyline but not St John's wort extract decreased self rated activity (P < 0.05). Both drugs caused significant qEEG changes. St John's wort extract increased theta power density. Amitriptyline increased theta as well as fast alpha power density.

Conclusions
Multiple doses of St John's wort extract do not affect heart rate variability    nor   cognitive   function.   Chronic   administration   of   amitriptyline   causes a decrement of HRV and subjective sedation but it does not impair cognitive performance.
Genetic polymorphisms in human CYP2A6 gene causing impaired nicotine metabolism
Authors: Yoshida Ryoko , Nakajima Miki , Watanabe Yuki , Kwon Jun‐Tack , Yokoi Tsuyoshi
Published: March 2003

Aims  Previously, we determined the phenotyping of in vivo nicotine metabolism and the genotyping of the CYP2A6 gene (CYP2A6*1 A, CYP2A6*1B, CYP2A6*2, CYP2A6*3, CYP2A6*4 and CYP2A6*5 ) in 92 Japanese and 209 Koreans. In the study, we found one Korean and four Japanese subjects genotyped as CYP2A6*1B/CYP2A6*4 who revealed impaired nicotine metabolism, although other many heterozygotes of CYP2A6*4 demonstrated normal nicotine metabolism (CYP2A6*4 is a whole deletion type). After our previous report, several CYP2A6 alleles, CYP2A6*6 (R128Q), CYP2A6*7 (I471T), and CYP2A6*8 (R485L), have been reported. The purpose of the present study was to clarify whether the impaired nicotine metabolism can be ascribed to these CYP2A6 alleles. Furthermore, we also determined whether the subjects possessing CYP2A6*1×2 (duplication) reveal higher nicotine metabolism.

Methods  Genotyping of CYP2A6 alleles, CYP2A6*6, CYP2A6*7, CYP2A6*8, and CYP2A6*1×2 was determined by PCR.

Results  The five poor metabolizers were re‐genotyped as CYP2A6*7/CYP2A6*4, suggesting that a single nucleotide polymorphism (SNP) causing I471T decreases nicotine metabolism in vivo. Furthermore, we found that two subjects out of five with a lower potency of nicotine metabolism possessed SNPs of CYP2A6*7 and CYP2A6*8 simultaneously. The novel allele was termed CYP2A6*10. In the 92 Japanese and 209 Koreans, the CYP2A6*6 allele was not found. The allele frequencies of CYP2A6*7, CYP2A6*8, and CYP2A6*10 were 6.5%, 2.2%, and 1.1%, respectively, in Japanese, and 3.6%, 1.4%, and 0.5%, respectively, in Koreans. The CYP2A6*1×2 allele was found in only one Korean subject (0.5%) whose nicotine metabolic potency was not very high.

Conclusions  It was clarified that the impaired in vivo nicotine metabolism was caused by CYP2A6*7 and CYP2A6*10 alleles.
In vitro–in vivo correlations for drugs eliminated by glucuronidation: Investigations with the model substrate zidovudine
Authors: Boase Sam , Miners John O.
Published: March 2003

Aims  To investigate the effects of incubation conditions on the kinetic constants for zidovudine (AZT) glucuronidation by human liver microsomes, and whether microsomal intrinsic clearance (CLint) derived for the various conditions predicted hepatic AZT clearance by glucuronidation (CLH) in vivo.

Methods  The effects of incubation constituents, particularly buffer type (phosphate, Tris) and activators (Brij58, alamethacin, UDP‐N‐acetylglucosamine (UDP‐NAcG)), on the kinetics of AZT glucuronidation by human liver microsomes was investigated. AZT glucuronide (AZTG) formation by microsomal incubations was quantified by h.p.l.c. Microsomal CLint values determined for the various experimental conditions were extrapolated to a whole organ CLint and these data were used to calculate in vivo CLH using the well‐stirred, parallel tube and dispersion models.

Results  Mean CLint values for Brij58 activated microsomes in both phosphate (3.66 ± 1.40 µl min−1 mg−1, 95% CI 1.92, 5.39) and Tris (3.79 ± 0.74 µl min−1 mg−1, 95% CI 2.87, 4.71) buffers were higher (P < 0.05) than the respective values for native microsomes (1.04 ± 0.42, 95% CI 0.53, 1.56 and 1.37 ± 0.30 µl min−1 mg−1, 95% CI 1.00, 1.73). Extrapolation of the microsomal data to a whole organ CLint and substitution of these values in the expressions for the well‐stirred, parallel tube and dispersion models underestimated the known in vivo blood AZT clearance by glucuronidation by 6.5‐ to 23‐fold (3.61–12.71 l h−1vs 82 l h−1). There was no significant difference in the CLH predicted by each of the models for each set of conditions. A wide range of incubation constituents and conditions were subsequently investigated to assess their effects on GAZT formation, including alamethacin, UDP‐NAcG, MgCl2, d‐saccharic acid 1,4‐lactone, ATP, GTP, and buffer pH and ionic strength. Of these, only decreasing the phosphate buffer concentration from 0.1 m to 0.02 m for Brij58 activated microsomes substantially increased the rate of GAZT formation, but the extrapolated CLH determined for this condition still underestimated known AZT glucuronidation clearance by more than 4‐fold. AZT was shown not to bind nonspecifically to microsomes. Analysis of published data for other glucuronidated drugs confirmed a trend for microsomal CLint to underestimate in vivo CLH.

Conclusions  AZT glucuronidation kinetics by human liver microsomes are markedly dependent on incubation conditions, and there is a need for interlaboratory standardization. Extrapolation of in vitro CLint underestimates in vivo hepatic clearance of drugs eliminated by glucuronidation.
Drug reimbursement: Indicators of inappropriate resource allocation
Authors: Bégaud Bernard , Bergman Ulf , Eichler Hans‐Georg , Leufkens Hubert G. M. , Meier Peter J.
Published: March 2003

Aims  In many countries, governments and third parties find themselves paying for (reimbursing) unproven, inadequate products limiting their ability to invest in therapies with evidence of relevant patient benefit. We examined how three characteristics, level of therapeutic evidence, susceptibility of inappropriate prescribing, and intercountry variation can be used to identify inefficiencies in pharmaceutical reimbursement among four European Union countries, Austria, Belgium, the Netherlands and Sweden.

Methods  Specific classes of medicines were chosen to provide useful examples of how healthcare resources could be reallocated. A high level of therapeutic evidence was defined as a substantial body of evidence in at least one indication with clear‐cut support of relevant patient benefit. The susceptibility of inappropriate prescribing was defined as the likelihood of prescribing a drug outside the scenario for which clear‐cut evidence (if any) has been documented to produce relevant benefit for the patient. The intercountry variation represents the variation in utilization of reimbursed drugs across the four countries.

Results  The combination of these characteristics provides a useful tool for assessing appropriate reimbursement decisions. It would be beneficial to healthcare payers as well as patients to move resources from products that have a low level of therapeutic evidence and a high susceptibility of inappropriate prescribing to products with a high level of therapeutic evidence and low susceptibility of inappropriate prescribing, and to use intercountry variation as a signal of drug classes that should be subject to further scrutiny.

Conclusions  A method is presented to help policy‐makers identify inefficiencies in the spending of limited health care resources, and to reallocate resources to products that have been shown to improve patient care through evidence‐based medicine.
Validation of a new fluorogenic real‐time PCR assay for detection of CYP2C9 allelic variants and CYP2C9 allelic distribution in a German population
Authors: Burian Maria , Grösch Sabine , Tegeder Irmgard , Geisslinger Gerd
Published: March 2003

Aims  The aim was to develop a fast detection method for the polymorphic alleles related to impaired CYP2C9‐mediated metabolism.

Methods  CYP2C9 genotypes were identified in 118 DNA samples using real‐time PCR (LightCycler) followed by melting curve analysis. All samples were re‐tested by validated PCR‐RFLP methodology.

Results  The concordance between the two methods was 100% for two variant alleles. The frequencies of CYP2C9*1 (wild type), CYP2C9*2 and CYP2C9*3 (with 95% confidence intervals) were 0.81(0.05), 0.14(0.04) and 0.05(0.03), respectively, and are similar to those observed in other Caucasian populations.

Conclusions  This assay is simple and rapid and may be used for CYP2C9‐genotyping in a clinical setting.
Determinants of undertreatment of hypercholesterolaemia in a population‐based study in The netherlands
Authors: Mantel‐Teeuwisse A. K. , Verschuren W. M. M. , Klungel O. H. , Porsius A. J. , De Boer A.
Published: March 2003

Prevalence of undertreatment of patients with hypercholesterolaemia is high and it remains uncertain which patients receive treatment.

The aim was to identify determinants of non‐use of lipid lowering drugs among those eligible for pharmacological treatment.

Data were obtained from two population‐based surveys (n=65,428) on cardiovascular disease risk factors conducted from 1987–1997 in The Netherlands. All respondents (age 20–59 years) completed a questionnaire which contained questions on demographic variables, cardiovascular disease (CVD) risk factors and medication use. Blood pressure, total‐cholesterol and HDL‐cholesterol levels were measured. Treatment eligibility was established for all respondents according to the Dutch Consensus Cholesterol 1998. This standard indicates pharmacological treatment in secondary prevention (unless Tc<5 mmol l−1) and for primary prevention when the absolute level of risk exceeds an age‐ and gender‐specific cut‐off point (based on the Framingham risk function). Secondary prevention was defined as a history of myocardial infarction (MI), cerebrovascular accident (CVA), coronary artery bypass grafts (CABG) or percutaneous transluminal coronary angioplasty (PTCA).

Multivariate logistic regression models were used to assess the association between demographic variables, CVD risk factors, medication use and treatment with lipid lowering drugs and to estimate odds ratios (OR) and their 95% confidence intervals.

Of all respondents, 2719 were eligible for lipid lowering treatment (4.2%). In secondary prevention, 137 of the 1225 eligible respondents were treated (11.2%). Age (OR=0.96 per year; 0.93–1.00), calendar year (OR= 0.69 per year; 0.59–0.82), a history of MI (OR=0.34; 0.20–0.57), CABG (OR=0.28; 0.16–0.47) or PTCA (OR=0.44; 0.24–0.79) and antihypertensive drug use (OR=0.56; 0.34–0.90) were inversely related to non‐use of lipid lowering drugs. Non‐use in secondary prevention increased with untreated hypertension (OR=1.37), diabetes mellitus (OR=2.21) and male gender (OR=1.20), although not statistically significant.

In primary prevention, 294 of the 1494 respondents eligible for treatment were treated (19.7%). Male gender (OR=12.2; 4.6–32.9), diabetes mellitus (OR=13.1; 6.6–25.8), untreated hypertension (systolic blood pressure >160 mmHg or diastolic blood pressure >95 mmHg) (OR=13.4; 7.0–25.8) current smoking (OR=11.7; 6.4–21.2) were most strongly associated with non‐use of lipid lowering drugs, while non‐use decreased with concomitant anticoagulant drug use (OR=0.05; 0.01–0.19). For age, we found an increase in risk of 1.26 (1.21–1.32) per year of age.

This study indicates that many subpopulations of respondents eligible for treatment with lipid lowering drugs but not receiving medication can be identified. Attention should be focused on the elderly, men (especially in primary prevention), patients with diabetes mellitus and untreated hypertensives.
6‐Thioguanine in azathioprine and 6‐mercaptopurine intolerant patients with inflammatory bowel disease
Authors: Derijks L. J. J. , De Jong D. J. , Gilissen L. P. L. , Engels L. G. J. B. , Mulder C. J. J. , Bos L. P. , Lohman J. J. H. M. , Hooymans P. M.
Published: March 2003

Azathioprine (AZA) and 6‐mercaptopurine (6‐MP) are frequently used in the treatment of inflammatory bowel disease (IBD). However, about 10–20% of IBD‐patients are unable to tolerate AZA and/or 6‐MP due to side‐effects. 6‐Thioguanine (6‐TG), the active metabolite of AZA and 6‐MP, may be an alternative in these cases.

We measured 6‐TG levels in erythrocytes 4 weeks after start of 6‐TG therapy in nine out‐patients with IBD. 6‐TG concentrations were considered to reach steady state in 4 weeks having a half‐life of approximately 5 days. The mean age of the patients was 41 years (range 24–59), three were male, six were female. Two patients were intolerant to 6‐MP, 5 to AZA and two to both drugs. Five patients received a daily dose of 20 mg, four were given 40 mg. The results are summarized in Table 1.

Patient characteristics.

Number
Sex
Age  (years)
IBD
Intolerance
Dose  (mg)
6‐TG (*)

1
M
59
UC
6‐MP
20
   552 (#)

2
M
51
UC
AZA
20
     270 (##)

3
F
24
CD
6‐MP
20
1013

4
F
35
CD
AZA
20
 819

5
F
46
UC
AZA/6‐MP
20
1072

6
F
24
CD
AZA
40
 986

7
M
44
UC
AZA
40
1359

8
F
51
CD
AZA
40
 703

9
F
34
CD
AZA/6‐MP
40
1666

* 6‐TG concentrations at t=4 weeks, at t=2 weeks (

#) and at t=1 week (

##) in pmol/8×10
8 RBC.

UC=ulcerative colitis, CD=Crohn's disease.

Poor correlation was found between dose and 6‐TG concentration (r : 0.34). 6‐TG concentrations after 6‐TG intake are relatively high compared with blood concentrations measured in AZA or 6‐MP treated patients (mean: 276, range: 0–792) [1]. Beside drug efficacy 6‐TG concentrations are also associated with bone marrow suppression, especially when these concentrations are high; Dubinsky et al. [1] measured a mean 6‐TG concentration of 490 in a pediatric leukopenic population treated with AZA or 6‐MP [2].

No leukopenia was observed in our 6‐TG treated group.

One of our patients showed an early allergic reaction to 6‐TG and developed high fever and erythema nodosum within the first week (patient 2). Another patient discontinued 6‐TG after 3 weeks because of total malaise (patient 1). Late, pharmacological explainable adverse reactions due to high 6‐TG concentrations did not occur in the 4 week period.

These results suggest that 6‐TG may serve as a safe alternative in AZA and 6‐MP intolerant IBD‐patients. Frequent 6‐TG concentration measurement and leukocyte counts are mandatory in determining optimal dose and guaranteeing safety. Further data are needed to establish safety and efficacy in the long term. We therefore initiated a prospective multicenter clinical trial.
Interaction of ibuprofen and probenecid with drug metabolizing enzyme phenotyping procedures using caffeine as the probe drug
Authors: Vrtic Fatima , Haefeli Walter E. , Drewe Jürgen , Krähenbühl Stephan , Wenk Markus
Published: March 2003

Aims To examine the suspected inhibitory potential of the over‐the‐counter (OTC) drug ibuprofen on N‐acetyltransferase 2 (NAT2) in vitro and in vivo and the possible implications for phenotyping procedures using caffeine as probe drug.

Methods We first studied the inhibitory effect of ibuprofen on NAT2 in vitro, using human liver cytosol and sulfamethazine as substrate. In vivo 15 fast and 15 slow acetylating healthy volunteers were treated with a single dose of ibuprofen (800 mg) orally and phenotyped for NAT2, CYP1A2, and xanthine oxidase (XO) with caffeine as probe drug before and during drug treatment. Because of unexpected in vivo results with ibuprofen this study was repeated in 20 healthy volunteers with probenecid, a model substrate of renal organic anion transport (OAT). For phenotyping tests a urine sample was collected 6 h after caffeine (200 mg) intake. The caffeine metabolites acetyl‐6‐formylamino‐3‐methyluracil (AFMU), 1‐methylxanthine (1MX), 1‐methyluric acid (1MU), and 1,7‐dimethyluric acid (17MU) were quantified by HPLC, and the corresponding metabolic ratios for CYP1A2, NAT2, and XO were then calculated. Genotyping for NAT2 was performed with standard PCR‐RFLP methods.

Results In vitro, with human liver cytosol an inhibition by ibuprofen of the acetylation of sulfamethazine with Ki values between 2.2 and 3.1 mm was observed. Surprisingly, in vivo a significant (P < 0.001) increase of the acetyl‐6‐formylamino‐3‐methyluracil/1‐methylxanthine (AFMU/1MX) urinary ratio from 0.97 ± 0.16 to 1.08 ± 0.18 (95% CI on the difference 0.049, 0.170) was found, indicating an apparent elevation of NAT2 activity. In contrast, no change was observed for the ratios used for XO and CYP1A2. Because an induction of NAT2 could be excluded, an interaction of ibuprofen with the tubular secretion of some of the caffeine metabolites was assumed. To prove this assumption, the in vivo study was repeated with probenecid, a model substrate of the renal OAT system. Again, a prominent elevation of the AFMU/1MX ratio from 0.97 ± 0.21 to 1.53 ± 0.35 was found (P < 0.002; 95% CI on the difference 0.237, 0.876), but also the XO ratio 1MU/1MX was significantly (P < 0.0001) increased from 1.34 ± 0.09 to 2.24 ± 0.14 (95% CI on difference 0.735, 1.059) due to a reduction of 1MX excretion.

Conclusions Substrates of OAT interact with renal excretion of caffeine metabolites and may falsify NAT2 and XO phenotyping results. Other phenotyping procedures, which are based on urinary metabolic ratios, should also be validated in this respect, especially in patients under polymedication.
Effect of short‐term administration of garlic supplements on single‐dose ritonavir pharmacokinetics in healthy volunteers
Authors: Gallicano Keith , Foster Brian , Choudhri Shurjeel
Published: March 2003

Aims  To evaluate the effect of acute dosing of garlic supplements on the single‐dose pharmacokinetics of ritonavir.

Methods  Ten healthy volunteers (five male, five female) were equally randomized in a crossover design to receive 400 mg of a single dose of ritonavir within 10 min after eating breakfast either alone or with 10 mg of Natural Source Odourless Garlic. They received a total of eight doses of garlic extract (2 × 5 mg capsules) taken twice daily for 4 days. Ritonavir and the seventh garlic dose were administered simultaneously.

Results  Coadministration of garlic nonsignificantly decreased area under the plasma concentration‐time curve (AUC(0,∞)) by −17% (90% confidence interval (CI), −31% to 0%; range −46% to 68%) and peak plasma concentration of ritonavir by −1% (90% CI, −25% to 31%; range −51% to 136%).

Conclusions  Acute dosing of the garlic capsules over 4 days did not significantly alter the single‐dose pharmacokinetics of ritonavir in healthy volunteers. Given the complex effects of both ritonavir and garlic on drug metabolism, the results of our study should not be extrapolated to steady‐state conditions, where the possibility of an interaction still needs to be evaluated.
Population pharmacokinetic analysis of meloxicam in rheumatoid arthritis patients
Authors: Meineke Ingolf , Türck Dietrich
Published: March 2003

Aim  To perform a nonlinear mixed effect modelling (NONMEM) population pharmacokinetic analysis of meloxicam plasma concentrations in rheumatoid arthritis (RA) patients participating in three clinical trials, and to evaluate the effects of age, weight, gender and concomitant medications on meloxicam pharmacokinetics.

Methods  Meloxicam was administered to RA patients once daily for 3 weeks or 6 months at doses between 7.5 and 60 mg. Plasma samples were obtained at least 7 days after the first dose and meloxicam plasma concentrations were quantified by h.p.l.c..

Results  NONMEM analysis was conducted on plasma samples derived from 586 patients. A one‐compartmental model was found to describe the data adequately. For a typical subject in the population, a clearance of 0.377 l h−1 (95% confidence interval (CI) 0.0304–0.449) in males and 0.347 l h−1 (95% CI 0.274‐0.419) in females was obtained. The volume of distribution was estimated to be 14.9 l. The findings were corroborated by subsequent analysis using WinBUGS. Analysis of covariates showed that age and gender both significantly (P < 0.005) affected clearance. The effect of age was relatively small and a dose adjustment of <10% was deemed unnecessary. Differences between males and females were attributed to differences in weight. No clinically relevant drug‐drug interactions were found, although sulphasalazine and glucocorticoids both significantly (P < 0.005) affected meloxicam clearance (+19% and − 12%, respectively). The mechanisms by which these agents affect meloxicam clearance remain to be elucidated.

Conclusions  The population pharmacokinetic meloxicam data from patients with RA gave similar results to those obtained from phase I trials. However, uncommon drug interactions may not be detected in phase I trials because of the small number of observations made.
Slow acetylator phenotype and genotype in HIV‐positive patients with sulphamethoxazole hypersensitivity
Authors: Alfirevic Ana , Stalford Anne C. , Vilar F. Javier , Wilkins Ed G. L. , Park B. Kevin , Pirmohamed Munir
Published: March 2003

Aims To test the role of acetylator status, and to investigate the reported discrepancy between acetylator phenotype and genotype in HIV‐positive patients with sulphamethoxazole (SMX) hypersensitivity.

Methods Forty HIV‐positive patients (32 of whom were SMX‐hypersensitive), and 26 healthy volunteers, were genotyped by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis, and phenotyped using dapsone (50 mg) as a probe, for acetylator status. Sequencing of the NAT2 exon was performed where discrepancy between phenotyping and genotyping was detected. Our results were also pooled with published studies addressing slow acetylator status in HIV‐positive SMX‐hypersensitive patients.

Results Slow acetylator genotype and phenotype frequencies did not differ between HIV‐positive SMX‐hypersensitive and nonhypersensitive patients, and healthy controls, which was further confirmed in a meta‐analysis of published studies (pooled odds ratio 2.25, 95% confidence interval 0.45, 11.17). Discordance between phenotype and genotype was resolved in four of the subjects by sequencing of the whole NAT2 exon, which revealed rare mutations, leaving three (9%) HIV‐positive SMX‐hypersensitive patients and one (4%) healthy volunteer who continued to demonstrate the discordance.

Conclusions Slow acetylator phenotype or genotype is unlikely to predispose to SMX hypersensitivity in HIV‐positive patients, although a minor role cannot be excluded. Phenotype–genotype discrepancies are partly due to nondetection of all rare alleles by PCR methodology, and can be circumvented by sequencing of the gene in patients showing a discrepancy.
Identification of pancreatic type I secreted phospholipase A2 in human epidermis and its determination by tape stripping
Authors: Mazereeuw-Hautier J. , Redoules D. , Tarroux R. , Charveron M. , Salles J.P. , Simon M.F. , Cerutti I. , Assalit M.F. , Gall Y. , Bonafe J.L. , Chap H.
Published: March 2003

Phospholipases A2 (PLA2) catalyse the release of fatty acids from the sn-2 position of phospholipids and have been suggested to play a key part in permeability barrier homeostasis. Using a sensitive and versatile fluorometric method, significant PLA2 activity has been detected in both human skin homogenates and tape strippings of stratum corneum. Based on various properties (resistance to heat and sulphuric acid treatment, neutral optimal pH, absolute requirement for millimolar calcium concentrations, inhibition by dithiothreitol and p-bromophenacyl bromide, and resistance to a trifluoromethyl ketone derivative of arachidonic acid, AACOCF3, a specific inhibitor of cytosolic PLA2), this enzyme was characterized as a secretory PLA2 (sPLA2). Immunohistochemistry revealed strong labelling of type I pancreatic sPLA2 at the stratum corneum–stratum granulosum junction, type II sPLA2 being undetectable. An increase in PLA2 activity in tape-stripped material from the deepest level of the stratum corneum was correlated with partial morphological disappearance of type I sPLA2 immunolabelling. Our data thus provide the first convincing evidence that pancreatic sPLA2 is significantly expressed in human epidermis, where it might participate in the accumulation of free fatty acids contributing to the permeability barrier. In addition, our method for determining PLA2 activity in easily available tape strippings should allow further clinical studies aimed to explore possible PLA2 abnormalities in various dermatoses.
Comedogenesis: some new aetiological, clinical and therapeutic strategies
Authors: Cunliffe W.J. , Holland D.B. , Clark S.M. , Stables G.I.
Published: March 2003

Hypercornification is an early feature of acne and precedes inflammation. It is associated with ductal hyperproliferation and there are many controlling factors such as androgens, retinoids and cytokines. Cycling of normal follicles and of comedones may explain the natural resolution of comedones and, in the longer term, resolution of the disease itself. There is a need to tailor treatment according to comedonal type. Suboptimal therapy can often result from inappropriate assessments of comedones, especially microcomedones, missed comedones, sandpaper comedones, submarine comedones and macrocomedones. Macrocomedones can produce devastating acne flares, particularly if patients are inappropriately prescribed oral isotretinoin. Gentle cautery under topical local anaesthesia is a useful therapy in the treatment of such lesions. The newer retinoids and new formulations of all-trans-retinoic acid show a better benefit/risk ratio. Evidence-based studies are required to allow adequate comparisons.
Very low incidence of p53 antibodies in adult non‐Hodgkin's lymphoma and multiple myeloma
Authors: Preudhomme Claude , Vanrumbeke Mickaël , Detourmignies Laurence , Facon Thierry , Lepelley Pascale , Soussi Thierry , Fenaux Pierre
Published: March 2003

In several types of solid tumours, circulating antibodies to p53 are seen in about a third of cases with a p53 mutation, but are absent in cases without p53 mutation. Therefore detection of those antibodies has relatively low sensitivity but high specificity in the detection of p53 mutations.

We looked for circulating p53 antibodies by ELISA in 56 adult non‐Hodgkin's lymphoma (NHL) and 80 multiple myeloma cases. A certain or highly probable p53 mutation was found by SSCP analysis, immunocyto‐ or immunohisto‐chemistry in 8/35 (23%) NHL cases and 2/19 (10%) MM cases analysed by these techniques. None of the 80 MM cases and only one of the 56 cases of NHL had circulating p53 antibodies. The positive case had Burkitt's lymphoma and a p53 missense mutation at codon 273. Thus, very few MM and NHL patients with a p53 mutation develop p53 antibodies and this test does not appear to be useful in haematological malignancies.
Adult biphenotypic acute leukaemia: an entity with poor prognosis which is related to unfavourable cytogenetics and P‐glycoprotein over‐expression
Authors: Legrand Ollivier , Perrot Jean‐Yves , Simonin Ghislaine , Baudard Marion , Cadiou Monique , Blanc Claude , Ramond Sylvie , ViguiÉ Franck , Marie Jean‐Pierre , Zittoun Robert
Published: March 2003

Biphenotypic acute leukaemia (BAL) patients represented 8% of the 287 de novo consecutive adult acute leukaemias (23 BAL, 230 acute myeloid leukaemia (AML) and 34 acute lymphoblastic leukaemia (ALL)) referred to our department during the last 4‐year period. Of these 23 BAL patients, 14 patients showed myeloid morphology and nine cases lymphoid morphology according to FAB criteria. There were no differences between lymphoid and myeloid BAL according to clinical and biological presentation and treatment outcome. We confirm the poor prognosis of BAL when compared to AML or ALL seen during the same period of time, in terms of complete remission (47%, 62% and 82% respectively, BAL v AML, NS and BAL v ALL, P = 0.006) and 4‐year overall survival (8.1%, 25.8% and 23.8% respectively, BAL v AML, P = 0.05 and BAL v ALL, P = 0.003). Comparing adult BAL patients with AML patients, we found an increase in poor prognostic factors: CD34+ phenotype (82% v 60% respectively, P = 0.03), unfavourable karyotype (60% v 20%, P < 0.0001) and Pgp over‐expression by RT‐PCR (0.705 v 0.107, P < 0.0001) and flow cytometry (0.824 v 0.391, P = 0.0001). MRP and LRP were not found to be poor prognostic factors. Comparing BAL patients with ALL patients, we found also an increase in poor prognostic factors: age (51 v 39, P = 0.003) and CD34+ phenotype (82% v 50%, P = 0.02). We conclude that BAL patients need a more aggressive treatment procedure, including high‐dose AraC or the use of Pgp modulators for first‐line therapy.
Feto‐maternal alloimmune thrombocytopenia: antenatal therapy with IvIgG and steroids — more questions than answers
Authors: Kaplan  , Murphy  , Kroll  , Waters  ,   for the European Working Group on FMAIT
Published: March 2003

The optimal antenatal therapy for fetal thrombocytopenia has not been determined. We analysed 37 cases managed by maternal therapy and observed a successful outcome of maternal treatment in 26% of IvIgG cases and in 10% of steroid‐treated cases. The significance of a plateau of the fetal platelet counts during pregnancy, 41% of IvIgG cases and 20% of cases treated with steroids, is uncertain. It may indicate a stabilization of thrombocytopenia, hence a beneficial effect of therapy, or the natural course of the platelet count in a low‐risk pregnancy. Overall outcome was unpredictable, but amongst the therapy failures there were proportionally more severely affected siblings. Further multicentre studies are necessary to establish the optimal antenatal management of high‐risk pregnancies.
Transient appearance of CD3+CD8+ T lymphocytes with monoclonal gene rearrangement of T‐cell receptor β locus
Authors: Nakahara Katsushi , Utsunomiya Atae , Hanada Shuichi , Takeshita Taketsugu , Uozumi Kimiharu , Yamamoto Kazuhito , Komatsu Hirokazu , Nitta Masakazu , Ueda Ryuzo , Tatsumi Eiji , Arima Terukatsu
Published: March 2003

A benign, transient proliferation of atypical lymphocytes and a monoclonal rearrangement of the T‐cell receptor β (TRB) locus was found in a 60‐year‐old woman who presented with low‐grade fever, anorexia and fatigue. A marked and transient atypical lymphocytosis (white blood cell count 90.5 × 109/l) with CD8 surface antigen improved without specific treatment. Although tests for IgM antibodies to hepatitis A, varicella zoster, Epstein‐Barr virus (EBV), and cytomegalovirus (CMV) were all negative, a monoclonal gene rearrangement of TRB locus was observed in the DNA of the proliferated atypical lymphocytes by Southern blotting. The clonal rearrangement and the atypical lymphocytes disappeared after 14 d, and the patient has remained well for 7 years. These results suggest that monoclonal proliferation of CD8 lymphocytes can occur based on a non‐neoplastic aetiology.
Antibodies to prothrombin crossreact with plasminogen in patients developing myocardial infarction
Authors: Puurunen Marja , Mänttäri Matti , Manninen Vesa , Palosuo Timo , Vaarala Outi
Published: March 2003

In a prospective study on healthy middle‐aged men, high level of antibodies to prothrombin implied a risk of myocardial infarction. The possible mechanism(s) of these antibodies in coronary thrombosis are not known. Because prothrombin belongs to the kringle proteins and shares structural homology with a fibrinolytic kringle protein plasminogen, we studied whether antibodies to prothrombin crossreact with plasminogen.

Sera from 17 healthy middle‐aged men who later developed myocardial infarction were studied. Binding of antibodies to immobilized prothrombin (EIA) was inhibited by using soluble prothrombin, plasminogen and synthetic peptides of 20 amino acids from plasminogen kringle 5 (P304, P305) and from prothrombin kringle 2 (P302) as inhibitors. The peptides contained the conserved pentapeptide CRNPD of the kringle proteins.

Soluble prothrombin inhibited up to 50% the binding of antibodies to immobilized prothrombin in all sera. Plasminogen inhibited binding in 9/17 (53%) sera (a decrease of at least 20%). P305 inhibited binding to prothrombin in 8/17 (47%), P304 in 4/17 (23%) and P302 in 6/17 (35%) sera. In structural analysis, presentation of the pentapeptide was conformationally different between the peptides.

We conclude that crossreactive antibodies binding to prothrombin and plasminogen occur in sera of patients later developing myocardial infarction. The crossreactive epitope seems to be conformational and include the conserved pentapeptide of the kringle proteins. These antibodies may interfere with the fibrinolytic function of plasminogen and contribute to the development of myocardial infarction.
Early viral complications following CD34‐selected autologous peripheral blood stem cell transplantation for non‐Hodgkin's lymphoma
Authors: Miyamoto Toshihiro , Gondo Hisashi , Miyoshi Yasushi , Shigematsu Hirokazu , Minematsu Toshio , Takenaka Katsuto , Tanimoto Kazuki , Horiuchi Takahiko , Asano Yoshinobu , Inaba Shoichi , Minamishima Yoichi , Niho Yoshiyuki
Published: March 2003

A patient with non‐Hodgkin's lymphoma who received a CD34‐selected autologous peripheral blood stem cell transplant (PBSCT) developed cytomegalovirus retinitis, adenovirus‐associated haemorrhagic cystitis (HC) and fatal herpes simplex virus pneumonia. Depletion of mature T cells from the graft and a persistent decrease in CD4+ lymphocytes following PBSCT may have predisposed this patient to such viral infections. Infusion of cryopreserved autologous PBSC (containing mature T cells) was effective for adenovirus‐associated HC. Immunosuppression and resultant viral infections may affect patients receiving CD34‐selected autologous transplantation.
Essential monoclonal gammopathy with an IgM paraprotein that is a cryoglobulin with cold agglutinin and EDTA‐dependent platelet antibody properties
Authors: Pujol Misericordia , Ribera José Ma , Jimenez Carmen , Ribera Ana , Abad Elena , Feliu Evarist
Published: March 2003

A patient with apparent anaemia and thrombocytopenia caused by a monoclonal paraprotein is described. The patient's serum contained a monoclonal IgM kappa, a cryoglobulin and a cold agglutinin. The cryoglobulin, similar to the serum paraprotein, was a monoclonal IgM kappa. Serum was studied to determine the relationship of the cryoglobulin with the cold agglutinin. The cryoglobulin and cold agglutinin were found to be the same paraprotein. Moreover, with absorption and elution techniques the reactivity of the autoantibody with both erythrocytes and platelets was demonstrated.

Reports of cryoprecipitable cold agglutinins are rare and therefore this case is exceptional given that the IgM kappa paraprotein was found to be a cold agglutinin which was also reactive with platelets.
Detection of chimaeric transcripts of the immunoglobulin heavy chain and BCL6 genes by reverse‐transcriptase polymerase chain reaction in B‐cell non‐Hodgkin's lymphomas
Authors: Kawamata Norihiko , Nakamura Yuichi , Miki Toru , Sato Eriko , Isobe Yasushi , Furusawa Sinpei , Hirosawa Shinsaku , Oshimi Kazuo
Published: March 2003

T(3;14)(q27;q32) is frequently detected in B‐cell non‐Hodgkin's lymphomas, especially the diffuse large cell type and the follicular type. The BCL6 gene encoding a putative transcriptional factor which resides on 3q27 rearranges to the immunoglobulin heavy chain (IgH) gene on 14q32 in this chromosomal translocation. The upstream regulatory region of the BCL6 gene is replaced by the IgH gene. Deregulation of the BCL6 gene may contribute to tumourigenesis of these diseases. The rearrangement between the IgH and BCL6 genes generates chimaeric transcripts in which the joining (J) region of the IgH gene fuses to exon 3 of the BCL6 gene. We established a method to detect these chimaeric transcripts by reverse transcriptase polymerase chain reaction (RT‐PCR) using the consensus sequence of the J region and the sequence of exon 3 of the BCL6 gene as primers. Using the semi‐nested RT‐PCR method and a cell line carrying t(3;14)(q27;q32), we detected one lymphoma cell among 10 000 background cells. We detected these chimaeric transcripts in two out of 13 clinical samples by this method. This method can detect t(3;14)(q27;q32) easily, whereas this alteration is frequently overlooked by routine karyotype analysis. Since this technique is sensitive enough to detect a small number of lymphoma cells with this genetic abnormality, it could be employed to detect contaminating lymphoma cells in bone marrow and peripheral blood and minimal residual diseases.