bluuebunny/crossref_metadata_2025 huggingface dataset:
The gastrointestinal passage and release of beclomethasone dipropionate from oral delivery systems in ileostomy volunteers
Authors: Burggraaf J. , Van Haarst A. D. , Fockens P. , Schoemaker H. C. , Krauwinkel W. J. J. , Cohen A. F.
Published: March 2003

Aims
 To study the delivery of 15 mg beclomethasone 17,21‐dipropionate (BDP) to the distal part of the small bowel for three oral sustained‐release formulations (I‐III) and a reference capsule in volunteer ileostomists, and to compare these findings with the in vitro dissolution profiles.

Methods
 Two groups of nine ileostomy volunteers (aged 20–61 years), who were otherwise healthy, were enrolled in the study. The recovery of BDP and its metabolite beclomethasone 17‐monopropionate (B17P) in ileostomy effluent was investigated in a cross‐over study after administration of formulations I or II or a reference capsule containing micronised BDP, and in a second open study after administration of formulation III. Radio‐opaque granules were coadministered for evaluation of gastrointestinal passage. Ileostomy effluents were collected hourly for 10–12 h following drug intake. After marker beads had been counted on X‐rays, ileostomy collections were analysed for BDP and its metabolites. Cumulative recovery, lag‐time and mean transit time were determined for drug and marker beads.

Results
 Gastrointestinal passage characteristics were similar for all treatments. Total drug recovery was approximately three times higher for the sustained‐release formulations than for the reference capsule. Recovery of B17P from stoma fluid samples was significantly lower for formulation III than for formulations I and II.

Conclusions
 The novel oral formulations delivered substantial amounts of steroid drug at the distal small bowel/proximal colon, which may warrant further studies to evaluate clinical applicability.
Dose‐proportional pharmacokinetics of budesonide inhaled via Turbuhaler®
Authors: Kaiser  , Aaronson  , Dockhorn  , Edsbäcker  , Korenblat  , Källén
Published: March 2003

Aims The present pharmacokinetic study was undertaken to determine the dose proportionality of three different doses of budesonide—400 μg, 800 μg or 1600 μg administered twice daily by a dry‐powder inhaler (Turbuhaler® ) in adult patients with mild asthma.

Methods A total of 38 patients received budesonide by inhalation, 13 received 400 μg twice daily, 12 received 800 μg twice daily and 13 received 1600 μg twice daily. Mean FEV1 at inclusion was 3.4, 4.0 and 3.9 l min−1 in the three groups, respectively. Blood samples were taken after a single dose, and after 3 weeks of daily treatment, for pharmacokinetic evaluation. Plasma concentrations of budesonide were determined by liquid chromatography plus mass spectrometry.

Results Eleven evaluable patients remained in each dose group. Mean time to peak budesonide plasma concentration (tmax ) was short (0.28–0.40 h) and did not differ between treatment groups. Budesonide concentrations declined rapidly thereafter, indicating efficient pulmonary absorption and rapid elimination with a half‐life of approximately 3 h. Cmax was 1.4(2.0) nmol l−1 (single (repeated) doses), 2.6(3.6) nmol l−1 and 5.4(6.4) nmol l−1 after 400, 800 and 1600 μg twice daily, respectively. The corresponding results for the area under the plasma concentration vs time curve (AUC) were 271(325), 490(628) and 915(1096) nmol l−1 min. Ninety percent confidence intervals for pairwise dose‐normalized Cmax and AUC comparisons between groups were large but contained unity in all cases, thus indicating dose‐proportional pharmacokinetics. Regression on analysis supported these findings. Mean AUC after repeated doses (AUC(0,12 h,RD)) was on average 23% higher than the mean AUC after single doses (AUC(0,∞,SD)(P=0.04) with no significant differences between doses, indicating slight accumulation following bid dosing.

Conclusions In this relatively small study, budesonide inhaled via Turbuhaler® appeared to have dose‐proportional pharmacokinetics, both within and above the clinically recommended dose range for asthmatic patients.
The effect of nitric oxide inhibition on the renin response to frusemide, in man
Authors: Lee Alison F. C. , Kiely David G. , Coutie Wendy J. , Struthers Allan D.
Published: March 2003

Aims We wished to see if renin release in man was inhibited by nitric oxide blockade, suggesting a role for nitric oxide in renin release. Evidence from animal studies has shown variable effects on renin release depending on the model and stimulus used.

Methods Ten normal male volunteers, received either l‐NMMA as a front loaded infusion (4 mg kg−1 bolus, with 4 mg kg−1 infusion), or placebo, followed by an intravenous bolus of 5 mg frusemide to stimulate renin. To investigate whether any alteration in renin release was due to the pressor effect of the l‐NMMA, the experiment was repeated using an equipressor dose of phenylephrine (0.5 μg kg−1 min−1 ).

Results l‐NMMA caused the expected increase in mean arterial pressure (96±2.6 vs 89±3.3 mmHg P<0.05 [mean±s.e.mean]), and a reduction in heart rate (59±3.6 vs 67±2.5 beats min−1P<0.05). l‐NMMA completely blocked the renin rise following the bolus of frusemide (1.18±0.196 vs 1.96±0.333 ng ml−1 h−1P<0.01). Phenylephrine 0.5 μg kg−1 min−1 produced very similar haemodynamic effects to l‐NMMA, and also suppressed the renin response to frusemide (1.43±0.290 vs 2.67±0.342 ng ml−1 h−1P<0.01).

Conclusions In man, the renin inhibition seen with NO synthesis inhibition is similar to that seen with a standard pressor stimulus, hence inhibition of renin in man by l‐NMMA, may be due to both direct effects on macula densa cells and indirect haemodynamic effects.
Pharmacokinetics of dihydrocodeine and its active metabolite after single and multiple oral dosing
Authors: Ammon Susanne , Hofmann Ute , Griese Ernst‐Ulrich , Gugeler Nadja , Mikus Gerd
Published: March 2003

Aims The pharmacokinetics of dihydrocodeine (DHC) and its active metabolite dihydromorphine (DHM) were assessed after a single oral dose of DHC and after increasing doses of DHC at steady‐state.

Methods Twelve healthy male volunteers (18–45 years, CYP2D6 extensive metabolizers (EMs), MR<1 took a single oral dose (s.d.) of DHC 60 mg after breakfast. After 60 h DHC 60 mg was administered twice daily for 3 days, the dose was increased to 90 mg twice daily for 3 days, the final dose of 120 mg was administered twice daily for 3 days (multiple dose: m.d.). Blood sampling and urine collection: during 60 h after s.d. and during 12 h after m.d.

Results No significant differences in the area under the curve (AUC) of both, DHC and DHM could be detected after a single oral dose of 60 mg DHC (AUC (0,∞)) and during steady‐state doses of 60 mg DHC (AUC(0,12 h)). During increasing steady‐state doses of DHC, the data showed a dose linearity of AUC, maximal serum concentration (Cmax ) and minimal steady‐state serum levels (Cssmin) of both, DHC and DHM (P<0.0001), point estimates of DHC dose corrected AUCs were well within the bioequivalence range (60 mg: 0.989; 90%CI 0.951–1.028, 90 mg: 0.997; 90%CI 0.959–1.036, 120 mg: 0.977; 90%CI 0.940–1.016). O‐demethylation from DHC to DHM remained constant within the increasing steady‐state doses of DHC in the 12 extensive metabolizers of CYP2D6.

Conclusions In the studied dose range (60–120 mg) the pharmacokinetics of DHC and its active metabolite DHM are linear in EMs of CYP2D6.
An oral formulation of nicotine for release and absorption in the colon: its development and pharmacokinetics
Authors: Green  , Evans  , Rhodes  , Thomas  , Ranshaw  , Feyerabend  , Russell
Published: March 2003

Aims Ulcerative colitis is predominantly a disease of nonsmokers and transdermal nicotine has therapeutic value in active disease; however side‐effects are troublesome. The aim of this study was to develop an oral formulation of nicotine which would be slowly released in the colon over 6 h, and to examine its pharmacokinetic profile in 12 healthy volunteers, with measurements of serum nicotine and cotinine, its principal metabolite.

Methods Nicotine was combined with a polyacrylic carbomer, Carbopol 974P which was incorporated into 13 different vehicles and their release profiles examined in vitro. The polyglycolized glyceride, Gelucire 50/13, was chosen for subsequent kinetic studies because it consistently produced a suitable release pattern which was linear. Capsules containing 3 mg nicotine, combined with carbomer in Gelucire 50/13, were coated with an acrylic resin Eudragit L; this ensured the capsule would remain intact until the ileum. On 2 separate days, 6 and 15 mg nicotine, contained in 2 and 5 capsules, respectively, were administered to 12 subjects, all nonsmokers, mean age 28 years. Serial blood measurements were taken for 36 h, serum nicotine and cotinine concentrations were measured by gas liquid chromatography.

Results There was considerable intersubject variability in the nicotine and cotinine values. Plasma nicotine levels began to rise about 4 h after ingestion of the capsules, corresponding with the oro‐caecal transit time. Cmax nicotine values were 2.2 and 5 ng ml−1, obtained 7 h after the ingestion of 6 and 15 mg, respectively, of the formulation. The corresponding Cmax values for cotinine were 37 and 94.4 ng ml−1, occurring after 9–10 h. The mean for elimination half‐lives in the 24 studies, including the 6 and 15 mg doses, for nicotine were 4.3±2.7 h and for cotinine 16.8±7.5 h. With 6 mg nicotine‐carbomer, only 1 of 12 volunteers had possible side‐effects, but with the 15 mg dose 11 out of the 12 reported adverse effects which were systemic or gastrointestinal in nature—their timing corresponded with peak serum concentrations of nicotine.

Conclusions An oral formulation of nicotine has been developed; in the ileum and colon, this becomes available for slow linear release over 6 h and delivers high concentrations of nicotine for topical effect on the colon. 6 mg Nicotine was well tolerated, whilst 15 mg gave both systemic and gastrointestinal side‐effects. High concentrations of topical nicotine in the colon are achieved with relatively low systemic bioavailablity—reflected by the Cmax and AUC values for nicotine. This, or comparable formulations, may be of therapeutic value in ulcerative colitis.
Contribution of nitric oxide to β2‐adrenoceptor mediated vasodilatation in human forearm arterial vasculature
Authors: Majmudar  , Anumba  , Robson  , Ford
Published: March 2003

Aims β2‐adrenoceptor agonists are generally considered to produce endothelium independent vasodilatation through adenylate cyclase. We determined whether nitric oxide contributes to β2‐adrenoceptor vasodilatation in human arterial vasculature.

Methods Forearm blood flow responses to brachial intra‐arterial infusions of ritodrine (2.5–50 μg min−1 ), a selective β2‐adrenoceptor agonist, were determined in 24 healthy, normotensive subjects (mean age 22 years, 5F) on two occasions with initial and concomitant administration of l‐NMMA (800 μg min−1 ), an NO synthase inhibitor, or noradrenaline (5–30 ng min−1 ), a control constrictor not affecting basal NO activity. Responses to the endothelium dependent vasodilator serotonin (n=6) and an endothelium independent vasodilator GTN (n=9) were also determined.

Results Maximal dilatation to ritodrine during l‐NMMA infusion (310±32%; mean±s.e.mean) was reduced compared to that during noradrenaline infusion (417±41%, P<0.05), as were summary responses (1023±101 vs 1415±130; P<0.05). Responses to GTN were unaffected by l‐NMMA compared to noradrenaline; max 177±26 vs 169±20%, 95% CI for difference −33,48; P=0.68; summary response 361±51 vs 396±37, 95% CI −142,71; P=0.46. Dilator responses to serotonin were reduced by l‐NMMA; max 64±20 vs 163±26%, P<0.01; summary response 129±36 vs 293±60; P<0.05) and to a greater extent than ritodrine (58±7 vs 25±14%, P<0.05).

Conclusions β2‐adrenoceptor mediated vasodilatation in the human forearm has an NO mediated component. The underlying mechanism for this effect is unclear, but flow mediated vasodilatation is unlikely to be responsible.
Ticlopidine decreases the in vivo activity of CYP2C19 as measured by omeprazole metabolism
Authors: Tateishi Tomonori , Kumai Toshio , Watanabe Minoru , Nakura Hironori , Tanaka Masami , Kobayashi Shinichi
Published: March 2003

Aims To examine the effect of ticlopidine administration on the activities CYP2C19 and CYP3 A in vivo using omeprazole as a model substrate.

Methods A single dose of 40 mg omeprazole was administered orally with or without ticlopidine (300 mg daily for 6 days) to six Japanese extensive metabolisers with respect to CYP2C19. Blood samples were taken for the measurement of plasma concentrations of omeprazole, 5‐hydroxyomeprazole and omeprazole sulphone.

Results Ticlopidine administration increased omeprazole Cmax (1978±859/ 3442±569 (control phase/ticlopidine phase, nm )) and decreased the oral clearance of omeprazole (CL/F; 25.70±16.17/10.76±1.16 (control phase/ticlopidine phase, l h−1 )) significantly. The 5‐hydroxyomeprazole to omeprazole AUC ratio (0.817±0.448/0.236±0.053 (control phase/ticlopidine phase)) and the 5‐hydroxyomeprazole to omeprazole sulphone AUC ratio (1.114±0.782/0.256±0.051 (control phase/ticlopidine phase)) were decreased significantly after ticlopidine administration. The decrease in omeprazole CL/F and the 5‐hydroxyomeprazole to omeprazole AUC ratio correlated significantly with their respective absolute values when the drug was given alone. The decrease in CL/F following ticlopidine administration correlated with that in the 5‐hydroxyomeprazole to omeprazole AUC ratio.

Conclusions These findings suggest that ticlopidine inhibited the in vivo activity of CYP2C19, but not, or to a lesser extent CYP3 A4, and that the magnitude of inhibition by ticlopidine is related to the in vivo activity of CYP2C19 before inhibition.
Population pharmacokinetics of tolcapone in parkinsonian patients in dose finding studies
Authors: Jorga Karin , Fotteler Bärbel , Banken Ludger , Snell Paul , Steimer Jean‐Louis
Published: March 2003

Aims To use pharmacostatistical models to characterize tolcapone's pharmacokinetics in parkinsonian patients, and to identify any demographic subpopulations which may be at risk of either under‐ or over‐exposure to this catechol‐O‐methyltransferase (COMT) inhibitor.

Methods Four hundred and twelve patients participated in three multicentre, parallel, double‐blind, placebo‐controlled, dose‐finding studies and received either placebo or tolcapone (50, 200 or 400 mg three times daily) in addition to levodopa/decarboxylase inhibitor therapy. Sparse blood samples were obtained from 275 patients for tolcapone assay and the concentrations (1414 in total) were analysed using the NONMEM program.

Results The pharmacokinetic model which best described the data was a two‐compartment open model with first‐order absorption and possibly a lag‐time. Tolcapone pharmacokinetics were shown to be stable, with no systematic trend between 2 and 6 weeks of treatment. The absorption of the drug was shown to be rapid and concomitant food intake had only a minor effect on the relative bioavailability (10–20% reduction compared with fasting). The overall clearance of tolcapone could be estimated with good precision (approximately 4.5–5 l h−1 ), and none of the investigated covariates (e.g. sex, age, body weight) had any clinically significant influence on this parameter. The volume of distribution showed relatively high variability and was calculated to be approximately 30 l, leading to an estimated half‐life in patients of approximately 5–8 h.

Conclusions Using sparse concentrations and mixed effect‐effects modelling analysis it is possible to describe the pharmacokinetics of tolcapone in parkinsonian populations. The parameter estimates obtained agreed with those obtained from conventional pharmacokinetic studies and no subpopulation was shown to be at risk of either under‐ or over‐exposure to tolcapone.
Pharmacokinetics and pharmacodynamics of gliclazide in Caucasians and Australian Aborigines with type 2 diabetes
Authors: Davis, Timothy M. E. , Daly, Frank , Walsh, John P. , Ilett, Kenneth F. , Beilby, John P. , Dusci Leon J. , Barrett P. Hugh R.
Published: March 2003

Aims 
Gliclazide pharmacokinetics and pharmacodynamics were assessed in 9 Caucasians and 10 Australian Aborigines with uncomplicated type 2 diabetes.

Methods 
Subjects were on a stable dose of 80 mg gliclazide twice daily, took 160 mg on the morning of study and had a standard breakfast. No further gliclazide was given over the next 48 h. Regular blood samples were drawn for serum glucose, insulin and gliclazide assay. Gliclazide was measured using h.p.l.c. Noncompartmental analysis was used to describe primary data. A multicompartment model incorporating entero‐hepatic recirculation was fitted to group mean serum gliclazide profiles.

Results 
The Caucasians were older than the Aborigines (mean ± s.d. age 53.4 ± 12.2 vs 40.3 ± 6.9 years, P < 0.05) but had similar diabetes duration, body mass index and glycated haemoglobin. Noncompartmental analysis revealed no between‐group differences in gliclazide kinetics. Post‐breakfast serum glucose and insulin responses were also similar apart from a longer time to maximum concentration (tmax) for glucose amongst the Aborigines (2.6 ± 0.4 vs 2.2 ± 0.3 h in Caucasians; P = 0.024). Gliclazide tmax exhibited a skewed unimodal distribution and was not associated with gliclazide maximum concentration, or glucose or insulin responses. Most patients had a serum gliclazide profile suggestive of enterohepatic recirculation and/or biphasic absorption. Model‐derived estimates of the extent of putative enterohepatic recirculation were 30% and 20% of dose in Caucasians and Aborigines, respectively.

Conclusions 
Gliclazide is equally effective in Caucasian and Aboriginal diabetic patients. The pharmacokinetics of oral gliclazide appear more complex than previously thought. Gliclazide pharmacodynamics are unrelated to rate and extent of absorption, consistent with a threshold concentration for hypoglycaemic effect.
Nonspecific binding of drugs to human liver microsomes
Authors: McLure James A. , Miners John O. , Birkett Donald J.
Published: March 2003

Aims  To characterize the nonspecific binding to human liver microsomes of drugs with varying physicochemical characteristics, and to develop a model for the effect of nonspecific binding on the in vitro kinetics of drug metabolism enzymes.

Methods  The extent of nonspecific binding to human liver microsomes of the acidic drugs caffeine, naproxen, tolbutamide and phenytoin, and of the basic drugs amiodarone, amitriptyline and nortriptyline was investigated. These drugs were chosen for study on the basis of their lipophilicity, charge, and extent of ionization at pH 7.4. The fraction of drug unbound in the microsomal mixture, fu(mic), was determined by equilibrium dialysis against 0.1 m phosphate buffer, pH 7.4. The data were fitted to a standard saturable binding model defined by the binding affinity KD, and the maximum binding capacity Bmax. The derived binding parameters, KD and Bmax, were used to simulate the effects of saturable nonspecific binding on in vitro enzyme kinetics.

Results  The acidic drugs caffeine, tolbutamide and naproxen did not bind appreciably to the microsomal membrane. Phenytoin, a lipophilic weak acid which is mainly unionized at pH 7.4, was bound to a small extent (fu(mic) = 0.88) and the binding did not depend on drug concentration over the range used. The three weak bases amiodarone, amitriptyline and nortriptyline all bound extensively to the microsomal membrane. The binding was saturable for nortriptyline and amitriptyline. Bmax and KD values for nortriptyline at 1 mg ml−1 microsomal protein were 382 ± 54 µm and 147 ± 44 µm, respectively, and for amitriptyline were 375 ± 23 µm and 178 ± 33 µm, respectively. Bmax, but not KD, varied approximately proportionately with the microsome concentration. When KD is much less than the Km for a reaction, the apparent Km based on total drug can be corrected by multiplying by fu(mic). When the substrate concentration used in a kinetic study is similar to or greater than the KD (Km ≥ KD), simulations predict complex effects on the reaction kinetics. When expressed in terms of total drug concentrations, sigmoidal reaction velocity vs substrate concentration plots and curved Eadie Hofstee plots are predicted.

Conclusions  Nonspecific drug binding in microsomal incubation mixtures can be qualitatively predicted from the physicochemical characteristics of the drug substrate. The binding of lipophilic weak bases is saturable and can be described by a standard binding model. If the substrate concentrations used for in vitro kinetic studies are in the saturable binding range, complex effects are predicted on the reaction kinetics when expressed in terms of total (added) drug concentration. Sigmoidal reaction curves result which are similar to the Hill plots seen with cooperative substrate binding.
Antihypertensive drugs and the risk of idiopathic aplastic anaemia
Authors: Myers Marian Wald , Vasilakis Catherine , Kaufman Matthew R. , Jick Hershel
Published: March 2003

Aims
A recent report has raised concern that nifedipine may be associated with an increased risk of aplastic anaemia. This large population‐based study evaluated the risk of idiopathic aplastic anaemia in users of calcium channel blockers compared with that of other antihypertensive drugs.

Methods
The study was based on information derived from the General Practice Research Database. We conducted a follow‐up study with a nested case‐control analysis of 322 448 subjects who received antihypertensive drugs. Cases were people who had a first‐time diagnosis of aplastic anaemia during January 1, 1988 through September 30, 1997. The risk estimate of aplastic anaemia was calculated for all antihypertensive drugs. For the nested case‐control analysis, six controls were matched to each case on age, sex and general practice attended. Odds ratios compared the risk of idiopathic aplastic anaemia for all antihypertensive drugs relative to nonusers.

Results
There were 13 cases of newly diagnosed idiopathic aplastic anaemia. The estimated risk of aplastic anaemia per 100 000 users was 0.8 (95% CI 0.1, 4.7) for calcium channel blockers, 1.4 (95% CI 0.5, 4.1) for β‐adrenoceptor blockers, 2.3 (95% CI 0.6, 8.6) for angiotension‐converting enzyme (ACE) inhibitors and 5.9 (95% CI 1.6, 21.5) for users of other antihypertensive drugs. In the case‐control analysis of 13 cases and 77 controls, the odds ratio was 0.3 (95% CI 0.02, 3.3) for calcium channel blockers, 0.5 (95% CI 0.1, 2.5) for β‐adrenoceptor blockers, 0.7 (95% CI 0.1, 5.6) for ACE inhibitors, 1.2 (95% CI 0.1, 11.8) for users of other antihypertensive drugs and 0.7 (95% CI 0.1, 7.2) for users of multiple drugs with a calcium channel blocker compared with nonusers.

Conclusions
The present study suggests that the use of calcium channel blockers is not associated with an increased risk of aplastic anaemia.
Population pharmacokinetics of tacrolimus in Asian paediatric liver transplant patients
Authors: Sam W. J. , Aw M. , Quak S. H. , Lim S. M. , Charles B. G. , Chan S. Y. , Ho P. C.
Published: March 2003

Aims  The purpose of this study was to describe the population pharmacokinetics of intravenous and oral tacrolimus (FK506) in 20 Asian paediatric patients, aged 1–14 years, following liver transplantation and to identify possible relationships between clinical covariates and population parameter estimates.

Methods  Details of drug dosage histories, sampling times and concentrations were collected retrospectively from routine therapeutic drug monitoring data accumulated for at least 4 days after surgery. Before analysis, patients were randomly allocated to either the population data set (n = 16) or a validation data set (n = 4). The population data set was comprised of 771 concentration measurements of patients admitted over the last 3 years. Population modelling using the nonlinear mixed‐effects model (NONMEM) program was performed on the population data set, using a one‐compartment model with first‐order absorption and elimination. Population average parameter estimates of clearance (CL), volume of distribution (V) and oral bioavailability (F) were sought; a number of clinical and demographic variables were tested for their influence on these parameters.

Results  The final optimal population models related clearance to age, volume of distribution to body surface area and bioavailability to body weight and total bilirubin concentration. Predictive performance of this model evaluated using the validation data set, which comprised 86 concentrations, showed insignificant bias between observed and model‐predicted blood tacrolimus concentrations. A final analysis performed in all 20 patients identified the following relationships: CL (l h−1) = 1.46 *[1 + 0.339 * (AGE (years) −2.25)]; V (l) = 39.1 *[1 + 4.57 * (BSA (m2)−0.49)]; F = 0.197 *[1 + 0.0887 * (WT (kg) −11.4)] and F = 0.197 *[1 + 0.0887 * (WT (kg) −11.4)]*[1.61], if the total bilirubin ≥ 200 µmol l−1. The interpatient variabilities (CV%) in CL, V and F were 33.5%, 33.0% and 24.1%, respectively. The intrapatient variability (s.d.) among observed and model‐predicted blood concentrations was 5.79 ng ml−1.

Conclusions  In this study, the estimates of the pharmacokinetic parameters of tacrolimus agreed with those obtained from conventional pharmacokinetic studies. It also identified significant relationships in Asian paediatric liver transplant patients between the pharmacokinetics of tacrolimus and developmental characteristics of the patients.
A comparison of oral artesunate and artemether antimalarial bioactivities in acute falciparum malaria
Authors: Suputtamongkol Yupin , Newton Paul N. , Angus Brian , Teja‐Isavadharm Paktiya , Keeratithakul Duangsuda , Rasameesoraj Maneerat , Pukrittayakamee Sasithon , White Nicholas J.
Published: March 2003

Aims  Artesunate and artemether are the two most widely used artemisinin derivatives in the treatment of uncomplicated Plasmodium falciparum malaria, but there is little information on their comparative pharmacokinetics. The aim of this study was to examine the relative oral antimalarial bioavailability and pharmacokinetics of the two derivatives.

Methods  The pharmacokinetic properties of oral artesunate and artemether (4 mg kg−1) were compared in a randomized cross‐over study of 14 adult patients in western Thailand with acute uncomplicated Plasmodium falciparum malaria. Antimalarial activity was compared using a previously validated, sensitive bioassay.

Results  Despite a 29% lower molar dose, oral artesunate administration resulted in significantly larger mean area under the plasma antimalarial activity time curve and median maximum plasma antimalarial activity than after oral artemether (P ≤ 0.02). The mean (95% CI) oral antimalarial bioavailability of artemether, relative to oral artesunate, corrected for molar dose was 58 (40–76)%. The mean (95% CI) relative antimalarial bioavailability of artemether was lower on the first day of treatment, 31 (17–100)%, compared to the second day, 72 (44–118)% (P = 0.018). In vivo parasite clearance and time above the in vitro IC90 were similar for the two drugs, despite considerable differences in Cmax and AUC.

Conclusions  The oral antimalarial bioavailability following artemether was significantly lower than that after artesunate. Artemether oral antimalarial bioavailability is reduced in acute malaria.
Time trends in lipid lowering drug use in The Netherlands. Has the backlog of candidates for treatment been eliminated?
Authors: Mantel‐Teeuwisse Aukje K. , Klungel Olaf H. , Verschuren W. M. Monique , Porsius Arijan J. , De Boer Anthonius
Published: March 2003

Aims  To assess time trends in lipid lowering drug use in The Netherlands.

Methods  Data were obtained from the PHARMO‐database, comprising pharmacy records of approximately 300 000 people in The Netherlands. In the period from 1991–98, we estimated prevalence of lipid lowering drug use on the first Wednesday of October. A patient was defined as incident user if (s)he filled a prescription for lipid lowering medication after a 360 days lipid lowering drug free interval. Both prevalence and incidence estimates were weighted for the sex and age distribution of the general Dutch population.

Results  From 1991 to 1998, the prevalence of lipid lowering drug use increased from 0.5% (95% confidence interval (CI): 0.5, 0.6) to 2.3% (95% CI: 2.2, 2.4) in women and from 0.6% (95% CI: 0.6, 0.6) to 2.9% (95% CI: 2.8, 3.0) in men. Prevalence increased with increasing age and was highest in the age category 60–69 years (in 1998: 9.9% (95% CI: 9.4, 10.4) in women and 11.6% (95% CI: 11.0, 12.1) in men). In 1992, the estimated incidence of lipid lowering drug use was 251(95% CI: 226, 277)/100 000 person years in women and 251(95% CI: 225, 276)/100 000 person years in men. The largest incidence estimates were observed in 1996 (685(95% CI: 644, 726)/100 000 person years in women and 881(95% CI: 834, 928)/100 000 person years in men). After 1996, incidence stabilized in 1997 and decreased in 1998 to 599(561, 637)/100 000 person years in women and 731(688, 773)/100 000 person years in men. Most of the patients (approximately 95%) were treated with one lipid lowering agent. Statins were used by over 90% of patients from 1996 onwards. In 1998, 35% of the patients started with a statin that was not a first choice drug (mainly atorvastatin).

Conclusions  In the period from 1991–98, prevalence of lipid lowering drug use significantly increased in The Netherlands. However, incidence stabilized and decreased after 1996 which may be explained by the fact that the number of patients eligible for treatment was reached. The question remains whether lipid lowering medication was targeted to the appropriate patients.
Laser resurfacing of the skin for the improvement of facial acne scarring: a systematic review of the evidence
Authors: Jordan R. , Cummins C. , Burls A.
Published: March 2003

This review presents and evaluates the evidence of the effectiveness of laser resurfacing for facial acne scars. Primary studies of all types of design in any language were identified from MEDLINE, EMBASE, the Cochrane database, Science Citation Index and various internet sites. Studies were accepted if they included patients treated by any laser for atrophic or ice-pick acne scars. The quality of the studies was assessed and data extracted by two independent researchers. There were no controlled trials but 14 case series were found which reported the effects of either the carbon dioxide or erbium:YAG laser. All of the studies were of poor quality. The types and severity of scarring were poorly described and there was no standard scale used to measure scar improvement. There was no reliable or validated measure of patient satisfaction; most improvement was based on visual clinical judgement, in many cases without blinded assessment. The inaccurate use of ordinal scales meant that any improvement was impossible to quantify with any validity, although the evidence suggested that laser treatment had some efficacy (a range in individual patients of 25–90% for both the carbon dioxide laser and the erbium:YAG laser). Changes in pigmentation as a side-effect were common (in up to 44% of patients), although lasting only a few weeks. Laser resurfacing technology is increasingly used in clinical practice to treat acne scars. Despite the poor quality evidence, it is plausible that there is some improvement of acne scarring; there is insufficient information, however, for patients to make informed decisions on whether to opt for treatment and there is not enough evidence to compare the two types of laser. There is a particular lack of information about the psychological effects of acne scar improvement. Good quality randomized controlled trials are needed with standardized scarring scales and validated patient outcome measures in order to assess the effectiveness of laser resurfacing in this group of patients.
Expression of the inducible isoform of nitric oxide synthase in pigment cell lesions of the skin
Authors: Ahmed B. , Van Den Oord J.J.
Published: March 2003

Nitric oxide (NO) is a small molecule produced during the conversion of l-arginine to l-citrulline by NO synthase (NOS). Several isoforms of NOS exist, of which the Ca2+-independent, inducible NOS (iNOS or NOS2) is most prominently expressed by macrophages. iNOS activity and increased levels of iNOS have been found in various tumours and tumour cell lines but not in normal tissues; however, the precise role of NO in tumour progression has yet to be elucidated. We studied the expression of iNOS in paraffin sections of 41 benign naevi and 52 primary malignant melanomas (MM) of the skin, as well as in 13 metastatic MM. In addition, nitrotyrosine, indicative of NO production and formation of peroxynitrite, was studied in frozen sections of 13 naevi and 30 MM. Virtually all naevi expressed iNOS, but very few expressed nitrotyrosine, indicating either that iNOS in naevi is functionally inactive, or that naevus cells lack reactive oxygen radicals and thus do not form peroxynitrite. Normal melanocytes in adjacent uninvolved skin were unreactive for both markers. In MM, iNOS was most frequently expressed in the ‘pure’ and ‘invasive’ radial growth phase (RGP), whereas expression in the vertical growth phase (VGP) and metastatic phase occurred only in 76% of cases; moreover, in these latest phases of tumour progression, iNOS staining was weak and focal. We conclude that iNOS is expressed de novo in most benign pigment cell lesions. In MM (iNOS-generated) NO appears to play an important part in the early steps of invasion (i.e. the ‘invasive’ RGP), where it may stimulate neo-angiogenesis and may be a prerequisite for further tumour progression; this view is also supported by the finding of iNOS in the associated blood vessels in the papillary dermis. Finally, our data suggest that (iNOS-generated) NO plays a less significant part in the VGP and in metastatic melanoma.
Linear IgA disease with IgA antibodies directed against 200- and 280-kDa epidermal antigens
Authors: Fujimoto W. , Ohtsu T. , Toi Y. , Nakanishi G. , Arata J.
Published: March 2003

We report an 80-year-old man with the lamina lucida type of linear IgA disease, with IgA autoantibodies reactive with 200-kDa and 280-kDa epidermal proteins. The patient presented with widespread bullous lesions on his trunk and extremities without mucosal involvement. Histopathology of lesional skin showed a subepidermal blister with papillary microabscesses of neutrophils and a few eosinophils. Direct immunofluorescence microscopy of perilesional skin showed linear deposits of IgA and C3 at the basement membrane zone. The patient’s serum contained IgA autoantibodies that bound exclusively to the epidermal side of 1 mol L−1 NaCl split skin as determined by indirect immunofluorescence microscopy. Circulating IgA autoantibodies to 200- and 280-kDa antigens were detected in the patient’s serum by immunoblot analysis using extracts from normal human epidermis and human epidermal keratinocytes. These two antibodies, eluted from individual nitrocellulose membranes, reacted with the epidermal side of 1 mol L−1 NaCl split skin on indirect immunofluorescence microscopy, and bound to hemidesmosomes as determined by immunoperoxidase electron microscopy. This observation suggests the presence of hitherto uncharacterized 200- and 280-kDa hemidesmosomal proteins distinct from BPAG1, BPAG2 and β4 integrin as target antigens in linear IgA disease.
Illegitimate transcription: its use for studying genetic abnormalities in lymphoblastoid cells from patients with Glanzmann thrombasthenia
Authors: Negrier Claude , Vinciguerra Christine , Attali Olivier , Grenier Christine , Larcher Marie Estelle , Dechavanne Marc
Published: March 2003

Glanzmann thrombasthenia is the most common inherited disorder of platelets that may induce severe bleeding complications. Molecular biology techniques have offered the possibility to assess the basis of this chronic haemorrhagic disease at the molecular level. However, the accessibility of mRNA in platelets is limited by the availability of the patient's blood samples and the relatively weak amount of this material in these cells. Taking advantage of the genetic phenomenon of illegitimate transcription, we have demonstrated that glycoprotein IIb and glycoprotein IIIa mRNA could be detected in lymphoblastoid cell lines issued from normal EBV‐transformed lymphoblasts. We further analysed the sequences of the two glycoprotein transcripts in lymphoblastoid cell lines from two previously characterized patients presenting with Glanzmann thrombasthenia. The results showed that illegitimate transcripts presented similar molecular abnormalities to those found in platelets. These data demonstrated that the nucleotide sequences of illegitimate transcripts were identical to tissue‐specific mRNA found in platelets. We applied this methodology to screen for the genetic defect in a new thrombasthenic patient, and found a homozygous nonsense mutation GCA → TGA converting Arg8 to stop in the glycoprotein IIIa gene. This immortalized source of genetic material is therefore particularly useful for molecular genetic studies in inherited platelet disorders, avoiding repetitive and large blood samplings in frequently anaemic patients.
Long‐term bone marrow cultured stromal cells regulate myeloma tumour growth in vitro: studies with primary tumour cells and LTBMC‐dependent cell lines
Authors: Bloem Andries C. , Lamme Tanja , De Smet Martin , Kok Henriette , Vooijs Wim , Wijdenes John , Boom Saskia E. , Lokhorst Henk M.
Published: March 2003

Long‐term bone marrow cultured stromal cells (LTBMC) produce IL‐6 after contact with tumour cells from multiple myeloma patients. We found that LTBMC could substitute for exogenous IL‐6 in the stimulation of bone marrow plasma cells from myeloma patients with active disease in short‐term cultures. In addition, tumour cells of some patients with inactive disease, which were unresponsive to exogenous IL‐6, were induced to IL‐6‐dependent growth after LTBMC co‐culture. To study the role of LTBMC in myeloma tumour growth in vitro, plasma cell lines UM‐2 and UM‐3 were selected. UM‐2 and UM‐3 grew in contact with LTBMC and proliferation was blocked by antibodies against IL‐6, IL‐6 receptor (IL‐6R, gp80, CD126) or the common signal transducing unit, gp130 (CD130). Culture with IL‐6 alone or combined with GM‐CSF resulted in cell death via apoptosis. The combination of IL‐6 with soluble gp80, however, maintained in vitro proliferation of UM‐2 and UM‐3 cells. These data imply that LTBMC regulate myeloma growth in vitro via production of IL‐6, possibly via induction of a functional IL‐6 receptor on the tumour cells.
Bleeding symptoms in 27 Iranian patients with the combined deficiency of factor V and factor VIII
Authors: Peyvandi  , Tuddenham  , Akhtari  , Lak  , Mannucci
Published: March 2003

Inherited deficiency of factors V and VIII is the most frequent combined coagulation defect. The cases reported so far are mostly single cases or small series from different centres, making it difficult to evaluate the overall pattern of clinical manifestations of the combined defect. We examined at a single institution 27 Iranian patients. Mucocutaneous and post‐surgical bleeding were the most frequent clinical manifestations. The presence of two defects did not make the severity of bleeding greater than that expected in patients with single coagulation defects of similar degrees.
Direct activation of factor X by monocytes occurs during cardiopulmonary bypass
Authors: Parratt Rachel , Hunt Beverley J.
Published: March 2003

We hypothesized that monocyte procoagulant activity, which includes up‐regulation of tissue factor and direct activation of factor X by CD11b, is an activator of coagulation during cardiopulmonary bypass (CPB), because recent studies have cast doubt on the presumption that the surfaces of CPB activate the intrinsic pathway.

Sequential samples were taken from 17 patients undergoing cardiac surgery. During CPB a significant increase in thrombin–antithrombin complexes occurred (P<0.0005). Factor XIIa levels increased (P<0.005) but remained within the normal range. Total monocyte procoagulant activity was measured and a functional assay was developed to detect direct activation of factor X alone. There was a significant increase in total procoagulant activity on circulating monocytes from the start of CPB (P<0.005) to which direct factor X activation was a major contributor (P<0.05). Direct activation of factor X was inhibited by CD11b blocking peptides. Using flow cytometry, up‐regulation of monocyte CD11b (P<0.0005), but not up‐regulation of tissue factor, was found on circulating monocytes. Monocytes adherent on the oxygenator fibres showed increased CD11b expression (P<0.0001), but no tissue factor when assessed by fluorescent image analysis.

In conclusion, direct activation of factor X through monocyte CD11b occurs during CPB and appears to contribute to thrombin generation during CPB.
Interleukin‐6 is expressed by plasma cells from patients with multiple myeloma and monoclonal gammopathy of undetermined significance
Authors: Sati Hamdi I. A. , Apperley Jane F. , Greaves Mike , Lawry John , Gooding Roger , Russell R. Graham G. , Croucher Peter I.
Published: March 2003

Interleukin‐6 (IL‐6) is an important growth factor for human myeloma cells in vitro and in vivo. However, the identity of the cells producing IL‐6 in vivo in patients with multiple myeloma (MM) remains the subject of debate. We have developed a sensitive dual‐colour fluorescence in situ hybridization (FISH) technique to investigate the expression of IL‐6 mRNA by individual bone marrow plasma cells from patients with multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS) and healthy subjects. IL‐6 mRNA could be identified in all immunoglobulin light chain (IgLC) expressing cells from all patients with MM and MGUS. The IL‐6 protein could also be detected by direct immunofluorescence in all plasma cells (cytoplasmic light chain positive) from all patients with MM and MGUS. Furthermore, it was also possible to demonstrate cytoplasmic IL‐6 staining of plasma cells from patients with MM by flow cytometric analysis. In contrast, neither the IL‐6 mRNA or protein could be detected in normal plasma cells from healthy bone marrow donors. These data demonstrate that plasma cells from patients with MM and MGUS express the IL‐6 mRNA and synthesize the IL‐6 protein and support the hypothesis that autocrine synthesis of IL‐6 is of importance in patients with MM.
Large granular lymphocyte leukaemia occurring after renal transplantation
Authors: Gentile Teresa C. , Hadlock Kennethe G. , Uner Aysegul H. , Delal Buck , Squiers Elizabeth , Crowley Suzanne , Woodman Richard C. , Foung Steven K. H. , Poiesz Bernard J. , Loughran, JR Thomas P.
Published: March 2003

Post‐transplantation lymphoproliferative disorders (PTLD) are a clinicopathologically heterogenous group of lymphoid proliferations. The majority are of B‐cell origin and associated with Epstein‐Barr virus (EBV) infection. In contrast, the development of T‐cell PTLD is much less common and EBV does not appear to be involved in pathogenesis. In this report we describe three patients who developed large granular lymphocyte (LGL) leukaemia after renal transplantation. These patients had clonal expansion of CD3+, CD8+, CD57+, CD56− LGL. We were unable to detect CMV antigen or find evidence for EBV or human T‐cell leukaemia/lymphoma virus genome in the LGL from these patients. These data show that LGL leukaemia should be included as one of the types of T‐cell proliferations which can occur post transplant.
Plasma thrombopoietin levels in thrombocytopenic states: implication for a regulatory role of bone marrow megakaryocytes
Authors: Hou  , Andersson  , Stockelberg  , Mellqvist  , Ridell  , Wadenvik
Published: March 2003

To evaluate the diagnostic value of thrombopoietin (TPO, c‐mpl ligand) measurements, and clarify the regulatory mechanisms of TPO in normal and in thrombocytopenic conditions, the plasma TPO concentration was determined in normal individuals (n = 20), umbilical cord blood (n = 40), chronic idiopathic thrombocytopenic purpura (ITP; n = 16), in severe aplastic anaemia (SAA; n = 3), chemotherapy‐induced bone marrow hypoplasia (n = 10), myelodysplastic syndrome (MDS; n = 11), and sequentially during peripheral blood progenitor cell transplantation (n = 7). A commercially available ELISA and EDTA‐plasma samples were used for the analysis. The plasma TPO concentration in the normals and umbilical cord blood were 52 ± 12 pg/ml and 66 ± 12 pg/ml, respectively. The corresponding values in patients with SAA and chemotherapy‐induced bone marrow hypoplasia were 1514 ± 336 pg/ml and 1950 ± 1684 pg/ml, respectively, and the TPO concentration, measured sequentially after myeloablative chemotherapy and peripheral blood progenitor cell transplantation, was inversely related to the platelet count. In contrast, the plasma TPO recorded in patients with ITP (64 ± 20 pg/ml) and MDS (68 ± 23 pg/ml) were only slightly higher than normal levels. In conclusion, TPO levels were significantly elevated in patients in which bone marrow megakaryocytes and platelets in circulation were markedly reduced, whereas TPO levels were normal in ITP patients, and only slightly increased in the MDS patients. These latter patients displayed a preserved number of megakaryocytes in bone marrow biopsies. Our data support the suggestion that megakaryocyte mass affects the plasma TPO concentration. In thrombocytopenic patients a substantially increased plasma TPO implies deficient megakaryocyte numbers. However, TPO measurements do not distinguish between ITP and thrombocytopenia due to dysmegakaryopoiesis, as seen in MDS patients.
Nodal T‐cell lymphoma in an HTLV‐I‐endemic area: proviral HTLV‐I DNA, histological classification and clinical evaluation
Authors: Ohshima Koichi , Suzumiya Junji , Sato Kensaku , Kanda Motonobu , Sugihara Midori , Haraoka Seiji , Takeshita Morishige , Kikuchi Masahiro
Published: March 2003

Adult T‐cell leukaemia/lymphoma (ATLL) is a human malignancy associated with human T‐cell leukaemia virus type I (HTLV‐I). The histology usually indicates a pleomorphic type, but is not consistent. To clarify the relationship between the histological classification and prognosis in ATLL, and to confirm the significance of clonal HTLV‐I integration, we reclassified 572 cases with nodal T‐cell lymphoma in which the T‐cell phenotype and/or genotype was confirmed. In all cases the clonal integration of HTLV‐I proviral DNA in the lymph nodes was examined by Southern blot analysis. In addition, anti‐ATL antigen (ATLA) determination in the serum or PCR analysis of HTLV‐I pX amplification in lymph nodes was also performed. 66/313 (21%) cases with ATLA had no evidence of clonal HTLV‐I integration. 572 cases were classified into three groups: (A) cases with clonal integration (247 cases), (B) cases with ATLA without clonal integration of HTLV‐I proviral DNA (66 cases), (C) cases without ATLA (259 cases). Histologically, groups B and C frequently demonstrated large cell type and angioimmunoblastic lymphadenopathy with dysproteinaemia (AILD) type; however, group A tended to show a pleomorphic type. Clinically, group A showed a poorer prognosis than groups B and C.

In conclusion, group A cases were defined as ATLL (HTLV‐I‐associated T‐cell lymphoma), whereas group B was classified as T‐cell lymphoma, which had coincidently occurred in HTLV‐I infected carriers. The simplified classification of REAL indicated clinical outcome: the prognosis of ATLL was poor, the unspecified type was intermediate, whereas the other types of lymphoblastic, AILD and anaplastic large cell type were all relatively favourable.