bluuebunny/crossref_metadata_2025 huggingface dataset:
Does retention matter? Treatment duration and improvement in drug use
Authors: Zhang Zhiwei , Friedmann Peter D. , Gerstein Dean R.
Published: May 2003

Aim  This study examines whether there is a minimum threshold, continuous or non‐linear relationship between the duration of addiction treatment and improvements in drug use.

Design  Longitudinal cohort study of 62 drug treatment units and 4005 clients in the US National Treatment Improvement Evaluation Study, fielded from 1993 to 1995.

Subjects  Baseline and 1‐year follow‐up interviews with clients in methadone maintenance, out‐patient non‐methadone, short‐term residential and long‐term residential treatment programs.

Measures  Improvement in drug use is the difference between the client‐reported peak frequency of drug use (in days per month) in the year prior to the baseline interview minus the peak frequency in the year after discharge. Primary drug, and overall use of the major illicit drugs (heroin, cocaine powder, crack cocaine, and marijuana) are considered separately.

Results  Controlling for multiple factors, treatment duration had a positive linear relationship with primary drug use improvement among methadone clients and an inverted‐U‐shaped relationship with overall and primary drug use improvements among out‐patient and long‐term residential clients. Improvement with longer duration is greatest for long‐term residential clients.

Conclusions  Contrary to previous arguments for a sharp retention threshold for onset of treatment effects, we find smooth curves relating treatment duration to drug use improvements in methadone maintenance, out‐patient non‐methadone and long‐term residential modalities. These relationships are effectively linear for durations typically observed in single treatment episodes, but unusually long retention in out‐patient non‐methadone and long‐term residential units appear steadily less predictive of improvement.
Physicians’ opinions about medications to treat alcoholism
Authors: Mark Tami L. , Kranzler Henry R. , Song Xue , Bransberger Peace , Poole Virginia H. , Crosse Scott
Published: May 2003

Aims Medications play a limited role in the treatment of alcoholism. This paper examines physicians’ opinions about and use of two alcoholism medications currently approved in the US—disulfiram and naltrexone—and one alcoholism medication—acamprosate—that might be approved.

Design A total of 1388 substance abuse specialist physicians who were members of the American Academy of Addiction Psychiatry or the American Society of Addiction Medicine completed a questionnaire in 2001 (65% response rate).

Findings The average percentages of physicians’ patients with alcoholism who were prescribed the following medications were: 13% (naltrexone), 9% (disulfiram), 46% (antidepressants) and 11% (benzodiazepines). Almost all physicians had heard of naltrexone and disulfiram, but their self‐reported level of knowledge about these medications was lower than for antidepressants. Physicians estimated that naltrexone had a small‐to‐medium effect size, which was similar in magnitude to the effect size reported in recent meta‐analyses of randomized clinical trials. Physicians identified the following three courses of action as the most likely to result in greater use of medications to treat alcohol dependence: more research to develop new medications (33%), more education of physicians about existing medications (17%), and increased involvement of physicians in alcoholism treatment (17%).

Conclusions Physicians’ low rate of use of naltrexone may reflect its small‐to‐medium effect size.
Effects of reducing contingency management values on heroin and cocaine use for buprenorphine‐ and desipramine‐treated patients
Authors: Kosten Thomas , Poling James , Oliveto Alison
Published: May 2003

Aims  During 3 months where contingency management (CM) had an escalating value for each consecutive drug‐free urine (escalating CM), cocaine‐ and heroin‐abusing patients significantly increased drug‐free urines. The ‘escalating CM’ was eliminated during months 4–6 to assess any reduction in drug‐free urines.

Design  Patients who completed a 3‐month, randomized, double‐blind, trial evaluating CM versus non‐CM and desipramine (DMI) versus placebo, had an ‘escalating CM’ eliminated during months 4–6. The CM and non‐CM groups were compared using thrice‐weekly urine samples.

Setting  Out‐patient buprenorphine maintenance for 6 months.

Participants  All 75 of the 160 original study patients who completed month 3 of the clinical trial.

Intervention  The ‘escalating CM’ was eliminated for all 3 months and during months 5 and 6 the response requirement was also increased to two and then three consecutive drug‐free urines in order to obtain a voucher.

Measurements  Urine toxicology for opiates and cocaine.

Findings  After eliminating the ‘escalating CM’, the CM group showed a decline in combined opioid‐ and cocaine‐free urines. This decline within the CM group was greater in those treated with DMI than placebo.

Conclusions  Buprenorphine with DMI maintained drug abstinence after eliminating the ‘escalating CM’, but not after increasing the response requirement, suggesting the need for more intensive psychosocial interventions during CM.
Education of key personnel in student pubs leads to a decrease in alcohol consumption among the patrons: a randomized controlled trial
Authors: Johnsson Kent O. , Berglund Mats
Published: May 2003

Aims  To decrease alcohol consumption among patrons in student pubs by server‐training programmes.

Design  Randomized controlled trial.

Setting  University campus.

Participants  A total of 1322 students visiting local student pubs during ordinary pub evenings.

Intervention  Educational programmes were given to bartenders (n = 40) in a randomized design in six of 12 pubs on a university campus. Bartenders in control pubs were not given the programme.

Measurements  Breath alcohol concentration (BAC), expressed in percentage, among the patrons and the reported social atmosphere in the pub (‘high’, ‘cosy’ and ‘rowdy’) measured on a visual analogue scale in the pub before and after the intervention programme was given.

Findings  BACs of patrons in the intervention pubs were reduced by more than those of the patrons in the control pubs at a 1‐month follow‐up. The mean difference in BAC between intervention and control groups was −0.011% (95% confidence interval, 0.022–0.000). The intervention group also decreased more in reported level of ‘rowdy’ social atmosphere than did the control group. The mean difference was −6 points (95% confidence interval −11 to −1). No differences were found in reported ‘cosy’ and ‘high’ atmosphere.

Conclusion  Alcohol levels among the patrons were decreased and the ‘rowdy’ social atmosphere reduced in the intervention group. Server‐training programmes for personnel in student pubs could be a component in the prevention of alcohol problems in university student populations.
Pharmacokinetics of bambuterol in healthy subjects
Authors: Nyberg Lars , Rosenborg Johan , Weibull Eva , Jönsson Sven , Kennedy Britt‐Marie , Nilsson Marita
Published: May 2003

Aims To study the pharmacokinetics and bioavailability of the prodrug bambuterol and its bronchodilator moiety terbutaline in healthy subjects.

Methods Eight healthy subjects (four women) received intravenous doses of bambuterol and terbutaline. On a third occasion, they, plus another four subjects, ingested oral bambuterol as a single dose followed by repeated doses once daily for 7 days. Plasma concentrations and urinary excretion of bambuterol and terbutaline were measured.

Results After intravenous administration, renal clearances of bambuterol and terbutaline were similar (about 140 ml min−1 ), but there was a five‐fold difference in total clearance (bambuterol 1.25 l min−1, terbutaline 0.23 l min−1 ). Volume of distribution (Vss ) was 1.6 l kg−1 b.w. for both substances. A similar renal clearance of bambuterol was found during oral administration but that of terbutaline decreased (to about 120 ml min−1 ). Mean terminal half‐life of bambuterol was 2.6 h after intravenous and 12 h after oral administration, implying that uptake was rate‐limiting. Mean residence time of terbutaline generated from oral bambuterol was 34 h compared with 8.0 h when terbutaline as such was infused. Generated terbutaline had a bioavailability of 36% (28–46) after intravenous and 10.2% (6.1–13.2) after oral administration of the prodrug. Bambuterol was well tolerated. The mean activity of plasma cholinesterase, an enzyme catalyzing bambuterol metabolism, was inhibited between 30–60% during repeated oral dosing. It virtually regained original activity within 48 h after the last dose.

Conclusions The plasma concentration of terbutaline fluctuated little during repeated oral administration (mean peak:trough ratio 1.9), as a result of prolonged absorption of bambuterol and slow formation of terbutaline. Thus, the pharmacokinetic properties of bambuterol make it suitable for oral once‐daily dosage.
Pharmacokinetics of bambuterol in subjects homozygous for the atypical gene for plasma cholinesterase
Authors: Bang Ulla , Nyberg Lars , Rosenborg Johan , Viby‐Mogensen Jørgen
Published: May 2003

Aims It has been assumed that both plasma cholinesterase (EC 3.1.1.8) and oxidative enzymes are needed for optimum formation of the bronchodilator terbutaline from its biscarbamate prodrug bambuterol. The present study aimed at investigating the fate of bambuterol in subjects with deficient plasma cholinesterase but with normal oxidative (CYP2D6) capability.

Methods The pharmacokinetics of bambuterol and terbutaline were studied in four healthy subjects (two men and two women) being homozygous for the atypical gene for plasma cholinesterase. Their oxidative metabolism was apparently good as they were all rapid metabolizers of debrisoquine. Bambuterol hydrochloride 20 mg was given orally once daily for 10 days, and plasma and urine samples were taken for 1.5 days (plasma) and 4.5 days (urine) after administration of the last dose.

Results The pharmacokinetic parameters in the present study were grossly similar to those found in a study of bambuterol in subjects with normal plasma cholinesterase activity (N). However, subjects with atypical cholinesterase had a shorter terminal half‐life of bambuterol (a measure of uptake rate), 4.8–12.6 h vs 8.3–22.3 h in N, and slightly higher plasma concentrations of bambuterol (average concentrations 1.9–3.7 nmol l−1vs 1.5–3.1 nmol l−1 in N). Peak/trough terbutaline plasma concentrations ratios (2.1–3.2) were somewhat increased, but average plasma concentrations (8.3–14.5 nmol l−1 ) and terminal half‐life (16.5–21.8 h) of terbutaline did not differ.

Conclusions In Caucasian populations, one subject out of 2500 is homozygous for the atypical gene for plasma cholinesterase. The atypical enzyme has a much lower affinity for bambuterol than the normal enzyme. Nevertheless, the subjects with atypical cholinesterase were able to produce terbutaline as efficiently as normal subjects. This might be explained by an altered uptake and metabolism in the absence of plasma cholinesterase, or the importance of this enzyme for the formation of terbutaline from bambuterol in vivo may have been overestimated.
Use of the UK General Practice Research Database for pharmacoepidemiology
Authors: García Rodríguez Luis A. , Pérez Gutthann Susanne
Published: May 2003

The last decade has seen a surge in the use of computerized health care data for pharmacoepidemiology. Of all European databases, the General Practice Research Database (GPRD) in the UK, has been the most widely used for pharmacoepidemiological research. Since 1994, this database has belonged to the UK Department of Health, and is maintained by the Office of National Statistics (ONS). Currently, around 1500 general practitioners with a population coverage in excess of 3 million, systematically provide their computerized medical data anonymously to ONS. Validation studies of the GPRD have documented the recording of medical data into general practitioners’ computers to be near to complete. The GPRD collects truly population‐based data, has a size that makes it possible to follow‐up large cohorts of users of specific drugs, and includes both outpatient and inpatient clinical information. The access to original medical records is excellent. Desirable improvements to the GPRD would be additional computerized information on certain variables and linkage to other health care databases. Most published studies to date have been in the area of drug safety. The General Practice Research Database has proved that valuable data can be collected in a general practice setting. The full potential of this rich computerized database has yet to come. This experience should serve to encourage others to develop similar population‐based data in other countries.
Endothelin‐1 induces vasodilation in human skin by nociceptor fibres and release of nitric oxide
Authors: Wenzel René R. , Zbinden Stefan , Noll Georg , Meier Bernhard , Lüscher Thomas F.
Published: May 2003

Aims Endothelin is a peptide produced by endothelial cells with many biological properties. In the human skin microcirculation endothelin induces neurogenic vasodilation associated with burning pruritus. We investigated the mechanisms involved in this response.

Methods The effects of prolonged pretreatment with capsaicin, a specific inhibitor of polimodal nociceptor fibres, and of the nitric oxide synthase inhibitor l‐NMMA on endothelin‐1‐induced vasodilation were studied in 15 human subjects. Furthermore, we investigated the effects of the ETA‐selective antagonist PD147953 on bradykinin‐induced vasodilation.

Results After local injection, endothelin‐1 caused vasoconstriction at the injection site and a profound vasodilation in the surrounding area (flare reaction, P<0.01). This response was specific and not induced by saline, albumin, acetylcholine or an ET‐antagonist. Prolonged capsaicin pretreatment inhibited endothelin‐1 induced vasodilation in the area surrounding the injection site, but not the central vasoconstriction at the injection site. Bradykinin also induced a marked vasodilation in the area surrounding the injection site; this was not inhibited by an ETA‐selective antagonist, while the flare reaction was. l‐NMMA applied at the site of the flare reaction prevented endothelin‐1‐induced vasodilation.

Conclusions Endothelin‐1 in the human skin microcirculation stimulates polimodal nociceptor fibres leading to the release of nitric oxide. This response may play a pathophysiological role in inflammatory processes in the human skin.
Distribution and excretion of sertraline and N‐desmethylsertraline in human milk
Authors: Kristensen  , Ilett  , Dusci  , Hackett  , Yapp  , Wojnar‐Horton  , Roberts  , Paech
Published: May 2003

Aims To characterise milk/plasma (M/P) ratio and infant exposure, for sertraline and N‐desmethylsertraline, in breast‐feeding women taking sertraline for the treatment of depression.

Methods Eight women (mean age 28 years) taking sertraline (1.05 mg kg−1 day−1 ) and their infants (mean age 5.7 months) were studied. Sertraline and N‐desmethylsertraline in plasma and milk were measured by high‐performance liquid chromatography over a 24 h dose interval at steady‐state. M/P values were estimated from area under the plasma and milk concentration‐time curves. All milk produced was collected over the dose interval. Infant exposure was estimated as the product of actual or estimated milk production, and average drug concentration in milk, normalized to body weight and expressed as a percentage of the weight‐adjusted maternal dose.

Results Mean milk production was 321 ml day−1 (range 34–974 ml). Mean M/P values of 1.93 and 1.64 were calculated for sertraline and N‐desmethylsertraline respectively. Infant exposure estimated from actual milk produced was 0.2% and 0.3% of the weight‐adjusted maternal dose for sertraline and N‐desmethylsertraline (as sertraline equivalents) respectively. When calculated from estimated milk production (0.15 l kg−1 day−1 ), infant exposure was significantly greater (P<0.0001) at 0.90% and 1.32% for sertraline and N‐desmethylsertraline respectively. Neither sertraline nor its N‐desmethyl metabolite could be detected in plasma samples from the four infants tested. No adverse effects were observed in any of the eight infants and all had achieved normal developmental milestones.

Conclusions Irrespective of the method of calculation of infant exposure, the mean total dose of sertraline and its N‐desmethyl metabolite transmitted to infants via breast‐feeding is low and unlikely to cause any significant adverse effects.
Absorption kinetics of oral sotalol combined with cisapride and sublingual sotalol in healthy subjects
Authors: Deneer  , Lie‐A‐Huen  , Kingma  , Proost  , Kelder  , Brouwers
Published: May 2003

Aims To study the absorption kinetics of sotalol following administration of different formulations. A formulation which results in fast absorption might be useful in the episodic treatment of paroxysmal supraventricular tachycardia (SVT), atrial fibrillation (Afib) or atrial flutter (Afl).

Methods In an open randomized crossover study seven healthy male volunteers were given an intravenous infusion of 20 mg sotalol, for assessing the absolute bioavailability, an oral solution containing 80 mg sotalol, an oral solution containing both 80 mg sotalol and 20 mg cisapride and an 80 mg sotalol tablet, which was taken sublingually.

Results The addition of cisapride decreased the time at which maximum serum concentrations were reached (tmax ) from 2.79 (1.85–4.34) h to 1.16 (0.68–2.30) h (P=0.009) [95% CI: ‐2.59, −0.55] and increased the absorption rate constant (ka ) from 0.49 (0.31–0.69) h−1 to 1.26 (0.52–5.61) h−1 (P=0.017). The absolute bioavailability of sotalol was reduced by cisapride from 1.00±0.15 to 0.70±0.26 (P=0.006), while maximum serum concentrations of both oral solutions were not significantly different. Compared with the sublingually administered tablet with a median tmax of 2.12 (0.89–3.28) h, the sotalol/cisapride oral solution gave a smaller tmax (p=0.009) [95% CI: −1.64, −0.36]. The ka of the sotalol/cisapride solution was significanty (P=0.010) larger than the ka of 0.56 (0.33–0.75) h−1 found after sublingual administration of the tablet.

Conclusions The sotalol/cisapride oral solution might be suitable for the episodic treatment of SVT, Afib or Afl.
Verapamil SR and trandolapril combination therapy in hypertension—a clinical trial of factorial design
Authors: Scholze Juergen , Zilles Peter , Compagnone Daniele
Published: May 2003

Aims To investigate the dose‐response relationship and contribution of verapamil SR and trandolapril given in combination once a day for the treatment of essential hypertension.

Methods A randomized, double‐blind, placebo controlled, factorial, 12 arm parallel group comparison with placebo, verapamil SR (120, 180 mg), trandolapril (0.5, 1.0, 2.0 mg) covering all combinations of both drugs. A 4 week placebo run‐in period followed by 6 weeks of treatment. Four hundred and fifty‐six patients from office practice (22 centres) with mild to moderate hypertension enrolled and 426 with diastolic pressure ≥100 mm Hg at the end of run‐in period were randomized. Main outcome measures were reduction in sitting systolic (SBP) and sitting diastolic (DBP) blood pressure.

Results The combination of verapamil SR and trandolapril, particularly verapamil SR 180 mg and trandolapril 0.5 or 1.0 mg was significantly superior to both monocomponents at the same dose (P<0.05). For these combinations, the adjusted mean reductions in DBP from baseline to last visit were 14.1 and 16.0 mm Hg, respectively. Response surface analysis provided further evidence that these combinations were optimal for antihypertensive efficacy. All treatments were well tolerated. The incidence of adverse events did not differ significantly between treatment groups; the profile of adverse events on combination therapy was mild and consistent with that of each monocomponent.

Conclusions All dosage combinations of verapamil SR and trandolapril produced significantly greater reduction of blood pressure than the monotherapy at the same dosage. However, verapamil SR 180 mg in combination with trandolapril 1.0 mg was the dosage with the greatest blood pressure reduction and had the greatest effects compared with the monocomponents.
The influence of nifedipine and captopril on liver blood flow in healthy subjects
Authors: Burggraaf  , Schoemaker  , Kroon  , Cohen
Published: May 2003

Aims Application of single methods to assess liver blood flow (LBF) yielded conflicting results on the magnitude and duration of effect on LBF of oral nifedipine and captopril. The aim of this study was to investigate the influence of these drugs on LBF by simultaneous use of ICG infusion and echo‐Doppler.

Methods The study was performed according to a double‐blind, placebo‐controlled, randomized, cross‐over design in nine healthy male volunteers. After an overnight fast and an equilibration period, subjects received a continuous i.v. indocyanine green (ICG) infusion for 4 h. At presumed ICG steady state (t=45 min), subjects were dosed with oral nifedipine (20 mg), captopril (50 mg) or placebo. During the experiment, blood sampling for ICG assay and measurement of portal venous blood flow (echo‐Doppler) took place regularly. Treatments were compared using analysis of variance. Differences are reported with 95% confidence intervals (CI).

Results The area under the curves (AUC) for ICG over 1 h and over 3 h after nifedipine were 15% (difference in AUC: +0.6, +7.0 mg l−1 min) and 22% (+7.0, +28.4 mg l−1 min) lower compared with placebo. After captopril, the AUC values were 8–10% lower compared with placebo but the 95% CIs included zero. Portal venous flow was 15% (+5, +86 ml min−1 ) higher compared to placebo after nifedipine but not after captopril (−3%; −49, +33 ml min−1 ). The duration of effect on liver blood flow lasted approximately 2 h but was variable (range: 40–160 min). The time to maximal blood flow increase and the duration of effect after nifedipine were very similar for both measures of LBF. Changes in ICG concentrations could be reasonably well predicted from the changes in portal blood flow.

Conclusions Nifedipine increases LBF for a substantial period of time but the effect is variable between subjects. This effect could be detected by both the ICG method and echo‐Doppler and the findings of both methods were in agreement. In this respect it is likely that captopril does not influence LBF in healthy volunteers as no effect was detected with either method.
Distribution and excretion of venlafaxine and O‐desmethylvenlafaxine in human milk
Authors: Ilett  , Hackett  , Dusci  , Roberts  , Kristensen  , Paech  , Groves  , Yapp
Published: May 2003

Aims To characterise the transfer of venlafaxine (V) and its O‐desmethyl metabolite (ODV) into human milk by measuring milk/plasma (M/P) ratio, and to estimate the likely dose received by a breast‐fed infant.

Methods Milk and plasma samples were collected from three lactating women who were taking venlafaxine for depression, and were at steady‐state. In two of the patients, venous blood and milk samples were collected 0, 1, 2, 3, 4, 6, 8 and 12 h post dose, while in the third patient a single pair of blood and milk samples was obtained 0.83 h post dose. A plasma sample was obtained from each of their infants. V and ODV were measured in plasma and milk by high performance liquid chromatography. M/P was calculated and infant dose estimated as drug concentration in milk×a milk intake of 0.15 l kg−1 day−1, relative to the weight‐adjusted maternal dose.

Results Mean M/P for V was 4.1 (range 2.8–4.8) and 3.1 for ODV (range 2.8–3.8). The mean total infant dose (as V equivalents) was 7.6% (range 4.7–9.2%) of the maternal weight‐adjusted dose, with approximately equal amounts of V (3.5%) and ODV (4.1%) in the dose. ODV (median 100 μg l−1 ) was detected in the plasma of all three infants. The infants were healthy and showed no acute adverse effects.

Conclusions These preliminary data show that the total dose of V and ODV ingested by breast‐fed infants can be as high as 9.2% of maternal intake. Moreover there were measurable concentrations of ODV in the infants’ plasma. We recommend that exposed infants should be observed closely.
Assessment of hepatic blood flow using continuous infusion of high clearance drugs
Authors: Schoemaker  , Burggraaf  , Cohen
Published: May 2003

Aims To provide methods for the translation of the concentration‐time profile of highly cleared marker compounds into the underlying clearance and hepatic blood flow profile.

Methods Continuous infusion of indocyanine green or sorbitol was used to assess the effect of the hepatic blood flow modifiers exercise, somatostatin and octreotide. Three distinct methods are described for the translation of concentration into flow:

1. assuming successive phases of constant clearance

2. point to point estimation of clearance using estimates of concentration change

3. using a parametric description of the flow profile in combination with the differential equations describing the change in marker concentrations.

Results The marker compound concentration profiles are adequately described using the different methods. Exercise results in a decrease in hepatic blood flow of about 80%. Somatostatin and octreotide elicit an indistinguishable hepatic blood flow decrease from 1.49 to 1.07 l min−1. Return to baseline takes much longer for octreotide (half‐life 126±104 min) than for somatostatin (half‐life 4.29±3.55 min).

Conclusions Translation of concentration profiles into clearance profiles is possible making continuous assessment of hepatic blood flow feasible.
Different standards for reporting ADRs to herbal remedies and conventional OTC medicines: face‐to‐face interviews with 515 users of herbal remedies
Authors: Barnes Joanne , Mills Simon Y. , Abbot Neil C. , Willoughby Martin , Ernst Edzard
Published: May 2003

Aims To determine whether adverse drug reactions (ADRs) to herbal remedies would be reported differently from similar ADRs to conventional over‐the‐counter (OTC) medicines by herbal‐remedy users.

Methods Face‐to‐face interviews (using a structured questionnaire) with 515 users of herbal remedies were conducted in six pharmacy stores and six healthfood stores in the UK. The questionnaire focused on the likely course of action taken by herbal‐remedy users after experiencing an ADR associated with a conventional OTC medicine and a herbal remedy.

Results Following a ‘serious’ suspected ADR, 156 respondents (30.3%) would consult their GP irrespective of whether the ADR was associated with the use of a herbal remedy or a conventional OTC medicine, whereas 221 respondents (42.9%) would not consult their GP for a serious ADR associated with either type of preparation. One hundred and thirty‐four respondents (26.0%) would consult their GP for a serious ADR to a conventional OTC medicine, but not for a similar ADR to a herbal remedy, whereas four respondents (0.8%) would consult their GP for a serious ADR to a herbal remedy, but not for a similar ADR to a conventional OTC medicine. Similar differences were found in attitudes towards reporting ‘minor’ suspected ADRs.

Conclusions Consumers of herbal remedies would act differently with regard to reporting an ADR (serious or minor) to their GP depending on whether it was associated with a herbal remedy or a conventional OTC medicine. This has implications for herbal pharmacovigilance, particularly given the increasing use of OTC herbal remedies. The finding that a high proportion of respondents would not consult their GP or pharmacist following ADRs to conventional OTC medicines is also of concern.
Increased levels of vascular endothelial growth factor in induced sputum in asthmatic patients
Authors: Asai K. , Kanazawa H. , Kamoi H. , Shiraishi S. , Hirata K. , Yoshikawa J.
Published: May 2003

Background Vascular endothelial growth factor (VEGF) is highly expressed in the airway of asthmatic patients. As VEGF increases airway vascular permeability, consequent thickening of the airway wall mucosa may lead to narrowing of the airway lumen.

Objective We evaluated the relationship between VEGF levels in induced sputum and eosinophilic inflammatory profiles, and the degree of airway vascular permeability in asthmatic patients and we evaluated the effect of inhaled corticosteroids on VEGF levels in induced sputum.

Methods Induced sputum specimens were obtained from 28 glucocorticosteroids free asthmatics and 11 healthy control subjects. We examined VEGF levels and airway vascular permeability index in induced sputum. After the initial sputum induction, 21 asthmatics received 8‐week inhaled beclomethasone dipropionate (BDP, 800 µg/day) therapy, then sputum induction was repeated.

Results The VEGF levels in asthmatics were significantly higher than in healthy control subjects (P < 0.0001). The VEGF levels were negatively correlated with forced expiratory volume of 1 s (FEV1, % predicted, r = − 0.68, P < 0.001), the percentage of eosinophils (r = 0.51, P < 0.01) and ECP levels (r = 0.39, P < 0.05). Moreover, the VEGF levels were significantly correlated with airway vascular permeability index (r = 0.61, P < 0.001). After 8‐week inhaled BDP therapy, the VEGF levels were significantly decreased compared to pretreatment levels (P < 0.0001) and the VEGF levels were significantly correlated with airway vascular permeability index even in post‐treatment asthmatics (r = 0.62, P < 0.01).

Conclusion The VEGF levels in induced sputum were increased in asthmatics and its levels were associated with degree of airway narrowing and airway vascular permeability. These findings provide strong evidence that VEGF may play an important role in the pathogenesis of bronchial asthma.
Enhancement of gelatinase activity during development of subepithelial fibrosis in a murine model of asthma
Authors: Corbel M. , Caulet‐Maugendre S. , Germain N. , Lagente V. , Boichot E.
Published: May 2003

Background Chronic asthma is characterized by inflammatory cell infiltration and tissue remodelling leading to subepithelial fibrosis. Metalloproteinases (MMPs) are involved in degradation of extracellular matrix in most chronic inflammatory diseases.

Objective The aim of this study was to investigate the expression of MMPs in the development of inflammatory processes associated or not with the concomitant development of subepithelial fibrosis in an experimental model of asthma.

Methods Sensitized BP2 mice were challenged with ovalbumin (OA) every 2 weeks during 8 months. Several mice were removed once a month and bronchoalveolar lavages (BAL) or lung biopsies were performed.

Results Lung sections stained with picrosirius and hydroxyproline measurements showed a significant collagen deposition after 16 weeks of OA challenge, demonstrating the development of subepithelial fibrosis. Pulmonary inflammation was present from the first OA challenge and was consistent throughout the 8 months of the study. Moreover, an up‐regulation and activation of MMP‐9 and, to a less extent, MMP‐2 were observed in BAL fluid from challenged mice. The level of tissue inhibitor of metalloproteinases (TIMP)‐1 increased after 12 weeks of OA challenge vs. control mice.

Conclusion This study reveals that a decrease in the activation of the MMP‐9 due to the increase in TIMP‐1, could contribute to excessive collagen deposition following repeated antigen challenge in sensitized mice.
The production, storage and release of the neurotrophins nerve growth factor, brain‐derived neurotrophic factor and neurotrophin‐3 by human peripheral eosinophils in allergics and non‐allergics
Authors: Noga O. , Englmann C. , Hanf G. , Grützkau A. , Seybold J. , Kunkel G.
Published: May 2003

Background Recent studies have shown that neurotrophins are produced by and can act on several immune‐inflammatory cells. The origin of circulating as well as local neurotrophins is unknown.

Objectives The aim of this study was to assess whether eosinophils of allergic and non‐allergic donors produce, store and release the neurotrophic factors NGF, BDNF and NT‐3.

Methods Eosinophils were purified by negative immunoselection (purity > 96%) from allergic asthmatics and non‐allergic donors (25 to 53 years). The presence of mRNA for neurotrophic factors was evaluated by reverse transcription PCR. Specificity was demonstrated by cloning products and sequencing. Stored NGF, BDNF and NT‐3 was demonstrated by Western‐blotting and flow cytometry. Eosinophils were incubated and supernatants were collected for measurement of neurotrophic factors after cell stimulation with PAF. Neurotrophin content in eosinophil lysates was determined by ELISA.

Results Eosinophils demonstrate mRNA for neurotrophins. Proteins were detectable by Western blot and FACS analysis. Neurotrophins were found in the eosinophil lysates at different amounts comparing allergic and non‐allergic donors. Cell stimulation with PAF (10‐8–10‐5 M) after priming with GM‐CSF leads to a dose‐dependant release of NGF and BDNF.

Conclusions Eosinophils store, produce and release NGF, BDNF and NT‐3. They are a possible source of elevated neurotrophin levels found in allergy and asthma.
Mast cells play a partial role in allergen‐induced subepithelial fibrosis in a murine model of allergic asthma
Authors: Masuda T. , Tanaka H. , Komai M. , Nagao K. , Ishizaki M. , Kajiwara D. , Nagai H.
Published: May 2003

Background Role of mast cells in the development of allergen‐induced airway remodelling has not been fully investigated in vivo.

Objective To clarify the possible role of mast cells in the development of allergen‐induced airway remodelling, we compared their responses of genetically mast cell‐deficient mice, WBB6F1‐W/Wv (c‐kit mutant) and Sl/Sld (c‐kit ligand mutant) mice with those of congenic normal mice in a murine model of allergic asthma.

Methods Mice were sensitized to ovalbumin (OA) with alum, and exposed daily for 3 weeks to aerosolized OA. Twenty‐four hours after the last inhalation, bronchial responsiveness to acetylcholine (Ach) was measured, and bronchoalveolar lavage (BAL), and biochemical and histological examinations were performed.

Results In both sensitized mast cell‐deficient mice, the degree of bronchial hyper‐responsiveness to Ach, the number of inflammatory cells and the level of transforming growth factor‐β1 in BAL fluid, IgE response and goblet cell hyperplasia in the epithelium after repeated allergen provocation were not significantly different from those of congenic mice. In contrast, subepithelial fibrosis, evaluated in the fibrotic area around the airways, observed in congenic mice after repeated allergen challenge was partially attenuated in both mast cell‐deficient mice. In addition, the amount of hydroxyproline in the lung of mast cell‐deficient mice was significantly lower than that of congenic mice. Furthermore, the decreased fibrotic area and amount of hydroxyproline in W/Wv mice was completely recovered by reconstitution of tissue mast cells with bone marrow‐derived mast cells of congenic mice.

Conclusion These findings suggest that mast cells play a partial role in the development of allergen‐induced subepithelial fibrosis, although airway inflammation, epithelial remodelling and BHR caused by repeated allergen challenge are independent of mast cells, at least in this model.
Calcineurin antagonists differentially affect mediator secretion, p38 mitogen‐activated protein kinase and extracellular signal‐regulated kinases from immunologically activated human basophils
Authors: Plath K. E. S. , Grabbe J. , Gibbs B. F.
Published: May 2003

Background Basophils participate in allergic diseases by invading affected tissues and secreting histamine, leukotriene (LT)C4, IL‐4 and IL‐13 following FcεRI cross‐linking. A reduction of basophil mediator production is therefore of considerable therapeutical interest. Macrolactam derivatives, which inhibit calcineurin activation, may be candidates for antiallergic therapy as they reduce both symptoms of inflammatory skin disease in animal models and mast cell degranulation.

Objective To investigate the effects of the calcineurin antagonists ascomycin and cyclosporin A on IgE‐dependent mediator release from human basophils.

Methods Basophils were purified by Ficoll density centrifugation, elutriation and negative selection. Histamine release was measured spectrofluorometrically; LTC4, IL‐4 and IL‐13 secretions were assayed by enzyme‐linked immunosorbent assay (ELISA). Lysed cells were subjected to Western blotting using specific antibodies to phospho‐p38 mitogen‐activated protein kinase (MAPK) and extracellular signal‐regulated kinase (ERK)‐1 and ‐2.

Results Ascomycin (0.01 nm to 1 µm) and cyclosporin A (0.1 nm to 10 µm) strikingly inhibited (maximally 100%) anti‐IgE‐induced histamine and cytokine release from basophils, and these actions were unaffected by IL‐3 priming. Ascomycin, however, was less potent at blocking LTC4 secretion, whereas cyclosporin A was unable to block production of this mediator. In immunoblotting studies, ascomycin and cyclosporin A reduced IgE‐dependent p38 MAPK activation but were less potent at reducing ERK phosphorylation in basophils.

Conclusion Calcineurin antagonists like ascomycin and cyclosporin A block IgE‐dependent basophil degranulation and cytokine synthesis. Calcineurin may target p38 MAPK activation, but seems to have less activity on ERK phosphorylation. This is paralleled by a reduced or even absent effect of calcineurin antagonists on eicosanoid production.
Characterization of immunoglobulin E responses in Balb/c mice against the major allergens of timothy grass (Phleum pratense) pollen
Authors: Seitzer U. , Bussler H. , Kullmann B. , Petersen A. , Becker W.‐M. , Ahmed J.
Published: May 2003

Background Grass pollen, such as that from timothy grass (Phleum pratense), represents a major cause of type I allergy.

Objective To characterize the IgE immune response and to identify the major allergens eliciting an IgE response in a mouse model using pollen extract of P. pratense for sensitization, in order to assess analogies to human hyperreactivity and to gain information on the allergenic potential as determined by the IgE‐reactivity kinetics of defined allergens.

Methods Balb/c mice were sensitized with pollen extract or with purified natural allergens. Serum IgE levels, the induction of specific IgE antibodies and immediate hypersensitivity were monitored by ELISA, Western blot and a skin test, respectively.

Results The sensitized mice mounted a strong IgE response and showed IgE‐reactivity first against Phl p 5a and 5b, then Phl p 4 and 13 and lastly against Phl p 6. No IgE response was mounted against Phl p 1. However, all purified fractions examined (Phl p 5a, 5b, 6 and 1) induced specific IgE and showed similar kinetics of IgE induction as pollen extract (first Phl p 5a and 5b, then Phl p 6). Skin test experiments demonstrated positive reactivity only in sensitized mice.

Conclusion The IgE reactivity induced by the major allergens in Balb/c mice was very similar to that found in allergic patients, with the exception of Phl p 1. The kinetics of the specific IgE response was comparable using either pollen extract or the purified major allergens, indicating that the intrinsic properties of the allergens are of importance rather than their proportionate amounts in pollen extract. This model should prove to be suitable for investigations regarding the mechanisms of induction and manifestation of timothy grass pollen allergy and for the evaluation of therapeutic strategies.
In vitro effects of eicosanoids derived from different 20‐carbon fatty acids on T helper type 1 and T helper type 2 cytokine production in human whole‐blood cultures
Authors: Miles E. A. , Aston L. , Calder P. C.
Published: May 2003

Background Different series prostaglandins (PGs) and leukotrienes (LTs) are synthesized from different 20 carbon fatty acid precursors. The effects of the different series of PGs and LTs on production of T helper type 1 (Th1) and Th2 cytokines by human cells are not well established.

Objective To characterize the influence of PGs and LTs produced from different fatty acid precursors on the Th1 and Th2 cytokine profile in mitogen‐stimulated human whole‐blood cultures.

Methods Blood from healthy adult males was diluted and cultured with concanavalin A in the presence or absence of a range of concentrations of various PGs or LTs. Cytokine concentrations in culture supernatants were analysed by enzyme‐linked immunosorbent assay (ELISA).

Results PGE1, PGE2 and PGE3 significantly and dose‐dependently decreased the concentrations of the Th1 cytokines IL‐2 and IFN‐γ by up to 50% and 70%, respectively. The three PGs exhibited similar potency towards IFN‐γ production. At the highest concentration used (10−6 m) PGE1, but not PGE2 or PGE3, increased the concentration of the Th2 cytokine IL‐4 by about 70%. IL‐10 production was not affected by PGs. The ratio of the concentrations of IFN‐γ to IL‐4 was significantly decreased at PGE concentrations of 10−7 and 10−6 M with all three PGEs having similar effects. LTB4, LTC4 and LTC5 did not significantly affect production of the cytokines studied.

Conclusion PGE produced from different fatty acids significantly decrease Th1 cytokine production resulting in a shift in the Th1, Th2 balance in favour of a Th2 response. PGE produced from different fatty acid precursors are equipotent in their effects on human T lymphocytes. Thus, although changes in the pattern of dietary fatty intakes may contribute to the increased prevalence of atopic disease, this would probably not be mediated through substitution of one PGE with another from a different series. It may, however, be mediated through a change in the total amount of PGE produced at the site of antigen presentation.
Granule protein changes and membrane receptor phenotype in maturing human eosinophils cultured from CD34+ progenitors
Authors: Al‐Rabia M. W. , Blaylock M. G. , Sexton D. W. , Thomson L. , Walsh G. M.
Published: May 2003

Background Eosinophils are now recognized as major effector cells in allergic and asthmatic disease with a potent armoury of mediators whose release makes a major contribution to the inflammation underlying these conditions.

Objectives The purpose of this study was to compare cultured eosinophils (CE) with normal‐density peripheral blood eosinophils (PBE) in terms of their membrane receptor expression and to analyse the expression and storage of the eosinophil granule proteins major basic protein (MBP) and eosinophil cationic protein (ECP) during eosinophil maturation in vitro.

Methods Purified human peripheral blood CD34+ cells were cultured in the presence of recombinant human IL‐3, IL‐5, rhGM‐CSF, SCF, and FLT‐3 ligand. PBE were isolated by density gradient centrifugation and negative immunomagnetic selection. Expression of CD11b, CD18, CD45, CD45RA, CD45RB, CD45RO, CD69, CD95, IL‐5Rα, IL‐9Rα, CCR1, CCR3, and CXCR4 by CE as they matured in culture were assessed by immunostaining and flow cytometry and expression of these receptors compared with freshly isolated PBE. Immunohistochemical staining and labophot‐2TM light microscopy determined expression of MBP, ECP, and CD69 during eosinophil maturation.

Results Positive immunostaining for MBP and ECP was detectable in a proportion (15–20%) of CE as early as 3 days of culture even though these cells were mononuclear in appearance. The numbers of CE positive for both granule proteins increased in rhIL‐3 and rhIL‐5 treated cells to a maximum of ∼ 80% by day 28. Maturing eosinophils exhibited positive immunostaining for CD69 after 14, 21 and 28 days of culture. Compared with PBE, CE had lower expression of pan‐CD45 and CD45 isoforms, CD95 and CD11b. In contrast, the specific mean fluorescence for CD69, CD18, IL‐5Rα, and IL‐9Rα was significantly elevated for CE compared with PBE. CCR3 expression by CE and PBE was similar with no expression of CXCR4 detected by either CE or PBE. No significant difference in expression of CCR1 was found between CE and PBE.

Conclusion These data suggest that CE and PBE share many phenotypic properties and both MBP and ECP appear early in eosinophil development in vitro. However, there are quantitative differences that may be a consequence of their immaturity and/or the influence of the cytokines used in their culture.
Inhaled endotoxin and organic dust particulates have synergistic proinflammatory effects in equine heaves (organic dust‐induced asthma)
Authors: Pirie R. S. , Collie D. D. S. , Dixon P. M. , McGorum B. C.
Published: May 2003

Background Equine heaves is a naturally occurring organic dust‐induced asthma characterized by airway neutrophilia, mucus hypersecretion and obstructive lung dysfunction. However, the relative role of different dust components in disease severity remains unclear.

Objective This study investigated the relative contribution of inhaled endotoxin and organic dust particulates (mainly mould spores) in inducing heaves in heaves‐susceptible horses.

Methods Control and heaves‐susceptible horses received inhalation challenges with hay dust suspension (HDS) before and after lipopolysaccharide (LPS) depletion. Heaves‐susceptible horses also received inhalation challenge with HDS particulates with and without the addition of LPS and were housed in two separate dusty environments during which mould and endotoxin exposure was measured. The airway inflammatory and functional response to each challenge was measured.

Results Depletion of endotoxin from HDS attenuated the airway neutrophilia and abrogated the airway dysfunction induced in heaves horses by inhaled HDS. The airway response was re‐established by adding back LPS to the depleted HDS, confirming that the attenuation in airway response was due specifically to endotoxin depletion. Interestingly, the magnitude of alteration in airway response following endotoxin depletion and add‐back was greater than that which could be attributed solely to endotoxin per se, indicating that the LPS activity was enhanced by the other dust components. Consistent with this possibility, washed particulates harvested from HDS enhanced the airway response to inhaled LPS in heaves horses. Heaves horses given two different hay/straw challenges had a significantly different severity of airway inflammation and dysfunction, despite airborne dust and endotoxin concentrations in the horses' breathing zones being similar.

Conclusion Although inhaled endotoxin appears not to be the only determinant of disease severity in heaves, it does contribute significantly to the induction of airway inflammation and dysfunction. This contribution is largely via the synergistic action of inhaled endotoxin and organic dust particulates, although other soluble dust components also contribute to a lesser degree.