[Recreational athletes and doping--a survey in 11 gyms in the area of Frankfurt/Main]. / Doping bei Freizeitsportlern--Eine Untersuchung in 11 Fitnessstudios im Raum Frankfurt am Main.

BACKGROUND: Doping no longer concerns exclusively competitive sports, but also recreational sports. METHOD: Survey of 484 recreational athletes in 11 gyms in the area of Frankfurt/Main. RESULTS: 12.9% of the men and 3.6% of the women reported to take anabolic drugs. Theyconsumed anabolic steroids (100%; 35% p.o., 71% parenterally), stimulants (14%) and growth hormone (5%). Suppliers were friends (39%), sports mates (28%), physicians (28%) and coaches (6%). The acquisition costs amounted to an average intake over 9 weeks to 175 Euro. Information about doping side effects came from literature (67%), physicians (38%), sports mates and the so-called Black Book (14% respectively), coaches, friends and Internet (5% respectively). 2% of the athletes with abuse of doping substances were smokers, 11% had a drink several times a week, 3% also consumed other drugs, 35% had consumed other drugs in the past. Abusers of doping substances primarily intended to increase muscle size (86%) and strength (61%). CONCLUSION: From a sports medical point of view it is concerning that the proportion of doping drugs prescribed by physicians has doubled in the decade after the publication of the predecessor study in Northern Germany despite optimized sports medical and legal education measures.

Two-year results from an open-label, multicentre, phase III study evaluating the safety and efficacy of canakinumab in patients with cryopyrin-associated periodic syndrome across different severity phenotypes.

OBJECTIVE: Longer-term effects of prolonged selective interleukin-1ß blockade with canakinumab were evaluated in the largest cohort of cryopyrin-associated periodic syndrome (CAPS) patients studied to date. METHODS: Adult and paediatric CAPS patients (n=166, including canakinumab-naive and pretreated patients from previous studies) received canakinumab subcutaneously 150 mg or 2 mg/kg (≤40 kg) every 8 weeks for up to 2 years. Response and relapse was assessed using scores for disease activity, skin rash and C-reactive protein (CRP) and/or serum amyloid A (SAA) levels. RESULTS: Complete response was achieved in 85 of 109 canakinumab-naive patients (78%; 79/85 patients within 8 days, and five patients between days 10 and 21). Of 141 patients with an available relapse assessment, 90% did not relapse, their CRP/SAA levels normalised (<10 mg/l) by day 8, and remained in the normal range thereafter. Median treatment duration was 414 days (29-687 days). Upward adjustments of dose or frequency were needed in 24.1% patients; mostly children and those with severe CAPS. Predominant adverse events (AE) were infections (65.7%) of mostly mild-to-moderate severity. Serious AE reported in 18 patients (10.8%) were mainly infections and were responsive to standard treatment. The majority of patients (92%) reported having no injection-site reactions and only 8% patients reported mild-to-moderate reactions. Patients receiving vaccination (15%) showed normal immune response. CONCLUSIONS: Subcutaneous canakinumab 150 mg every 8 weeks was well tolerated and provided substantial disease control in children and adults across all CAPS phenotypes. Higher canakinumab doses in younger patients and more severe CAPS disease were efficacious in achieving complete responses without evidence of increased AE. TRIAL REGISTRATION NUMBER: NCT00685373 (clinicaltrials.gov).

The use of modular femoral head trials to centre the Explant blade facilitates retrieval of well-fixed acetabular components with minimal bone loss.

BACKGROUND: The Zimmer-Explant system has made removal of a well-fixed monobloc acetabular component less challenging, but depends on the presence of an intact liner for instrument centralization. We report the outcome of 15 hips with well-fixed, cementless resurfacing sockets, which were removed using a modification of the existing method. We conclude that the existing Explant system combined with modular trial heads allows safe removal of monobloc shells with minimal bone loss. METHODS: Fifteen patients who underwent removal of a well-fixed, acetabular resurfacing component at the time of revision arthroplasty were identified from the unit's prospective arthroplasty database from 2005. RESULT: The final reamer used during reconstruction was only 1 or 2 mm larger than the outer diameter of the revised cup.

Determination of nicotine and cotinine in human serum by means of LC/MS.

As part of a joint clinical research project to study the effects of nicotine on the brain, a HPLC electrospray ionisation mass spectrometry method with a solid-phase extraction sample preparation was developed for the quantitative determination of nicotine and cotinine in human serum in volunteers. The measured concentrations of nicotine and cotinine were used as control for smoking behaviour. A X-Bridge-column from Waters, and a SSQ 7000 single quadropole mass spectrometer with a TSP liquid chromatographic system were used. The method includes a simple and robust sample preparation and this assay has been shown to be of a sufficient sensitivity for this application. The limits of quantification were 5 and 2ng/ml for cotinine and nicotine, respectively. A simultaneous study was conducted to measure nicotine receptor availability and the vigilance in the same group of volunteers.

Pharmacokinetics and clinical toxicity of prilocaine and ropivacaine following combined drug administration in brachial plexus anesthesia.

OBJECTIVE: Local anesthetics (LA) are often administered in combination for regional anesthesia in order to obtain the specific advantages (onset and duration of effect) of each drug. However, few data on the safety of such combinations are available and consequently plasma concentrations possibly associated with toxicity and interactions between the specific anesthetics are not sufficiently established. We measured pharmacokinetics and toxicity parameters of prilocaine and ropivacaine after combined use as single doses in brachial plexus blockade. METHODS: In an open clinical study using a combined dose regime (300 mg prilocaine followed immediately by 75 mg ropivacaine) total plasma concentrations of prilocaine and ropivacaine were measured serially in 60 patients using a gas-chromatographic method. The data were analyzed regarding a relationship with central nervous and cardiovascular toxicity. RESULTS: Following the administration in combination prilocaine and ropivacaine were rapidly absorbed. Mean prilocaine peak plasma concentrations (mean Cmax = 1.51 microg/ml) were measured between 15 and 30 min after injection. Highest ropivacaine plasma concentrations (mean Cmax = 1.12 microg/ml) were seen between 30 min and 1 hour after injection (calculated mean tmax = 44 min). One of 59 patients showed signs of myoclonus which were suspected of being due to intravascular injection. There was no relevant cardiovascular toxicity observed in terms of changes in the QRS complex, PQ interval prolongation, AV dissociation, occurrence of extrasystoles or sinus arrest. The pharmacokinetics of combined administration did not differ from those of prilocaine and ropivacaine given alone. CONCLUSION: The use of a combined prilocaine/ ropivacaine (300 mg/75 mg) dose regimen in patients given single dose for brachial plexus blockade can generally be regarded as safe with regard to peak plasma concentrations and cardiovascular toxicity and this holds true for patients with a higher perioperative risk profile (ASA III grading, American Society of Anesthesiologists). The considerable inter-individual variation in LA peak plasma concentrations observed in our patients and the one case of suspected accidental intravascular injection, highlight the necessity of adequate monitoring of the patients undergoing LA injections.

Determination of terephthalic acid isopropylamide in urine with a liquid chromatography/mass spectrometry (LC/MS) method.

A sensitive and simple liquid chromatography/mass spectrometry (LC/MS) method was developed for the determination of terephthalic acid isopropylamide, the final metabolite of procarbazine in human urine. A solid-phase extraction with C(18) cartridges was used followed by LC/MS with a single mass spectrometer (SSQ 7000 from Finnigan). Terephthalic acid isobutylamide was the internal standard. The quantification limit was 30 ng/mL in urine (6 x noise). This assay was applied for drug monitoring of terephthalic acid isopropylamide in urine after oral administration of procarbazine in children and adolescents with Hodgkin lymphomas.

Primary mouse hepatocytes for systems biology approaches: a standardized in vitro system for modelling of signal transduction pathways.

Complex cellular networks regulate regeneration, detoxification and differentiation of hepatocytes. By combining experimental data with mathematical modelling, systems biology holds great promises to elucidate the key regulatory mechanisms involved and predict targets for efficient intervention. For the generation of high-quality quantitative data suitable for mathematical modelling a standardised in vitro system is essential. Therefore the authors developed standard operating procedures for the preparation and cultivation of primary mouse hepatocytes. To reliably monitor the dynamic induction of signalling pathways, the authors established starvation conditions and evaluated the extent of starvation-associated stress by quantifying several metabolic functions of cultured primary hepatocytes, namely activities of glutathione-S-transferase, glutamine synthetase, CYP3A as well as secretion of lactate and urea into the culture medium. Establishment of constant metabolic activities after an initial decrease compared with freshly isolated hepatocytes showed that the cultured hepatocytes achieve a new equilibrium state that was not affected by our starving conditions. To verify the highly reproducible dynamic activation of signalling pathways in the in vitro system, the authors examined the JAK-STAT, SMAD, PI3 kinase, MAP kinase, NF-kappaB and Wnt/beta-catenin signalling pathways. For the induction of gp130, JAK1 and STAT3 phosphorylation IL6 was used, whereas TGFbeta was applied to activate the phosphorylation of SMAD1, SMAD2 and SMAD3. Both Akt/PKB and ERK1/2 phosphorylation were stimulated by the addition of hepatocyte growth factor. The time-dependent induction of a pool of signalling competent beta-catenin was monitored in response to the inhibition of GSK3beta. To analyse whether phosphorylation is actually leading to transcriptional responses, luciferase reporter gene constructs driven by multiple copies of TGFbeta-responsive motives were applied, demonstrating a dose-dependent increase in luciferase activity. Moreover, the induction of apoptosis by the TNF-like cytokine Fas ligand was studied in the in vitro system. Thus, the mouse hepatocyte in vitro system provides an important basis for the generation of high-quality quantitative data under standardised cell culture conditions that is essential to elucidate critical hepatocellular functions by the systems biology approach.

Evaluation of the pharmacokinetics of dalteparin in patients with renal insufficiency.

The pharmacokinetics of the low-molecular weight heparin (LMWH), dalteparin, was evaluated after a single intravenous bolus injection of 50 IU anti-Xa/kg in 8 healthy volunteers, 8 patients with moderate/severe renal failure (Cl(crea) 13.1-56.5 ml/min) and 8 hemodialysis patients. Venous blood samples were taken over a 1-day period to determine anti-Xa activity, anti-IIa activity and plasma levels of free tissue factor pathway inhibitor (free TFPI). Plasma anti-Xa and anti-IIa activities were measured using chromogenic assays and free TFPI levels using an ELISA technique. The anti-Xa clearance was significantly decreased (p < 0.05) in both groups with renal insufficiency when compared with healthy volunteers. There was a positive correlation between creatinine clearance and anti-Xa clearance in the healthy volunteers and patients with moderate/severe renal failure. The anti-Ila activity was characterized by 3- to 4-fold lower plasma concentrations and faster elimination compared with the anti-Xa activity. In patients with moderate/severe renal failure the elimination of anti-lla was only slightly decreased, whereas in hemodialysis patients anti-Ila clearance was significantly decreased (p < 0.01). There was no correlation between creatinine clearance and anti-IIa clearance. The baseline mean free TFPI plasma levels in the two groups with renal insufficiency were significantly higher (p < 0.01) than in healthy volunteers. Dalteparin administration induced a transient, 6.0- to 8.1-fold increase in the free TFPI values in the three study groups. Dalteparin induced an increase in C(max) and AUC(0 - infinity) values of free TFPI in the two groups with renal insufficiency that was higher than in healthy volunteers. No bleeding complications occurred during the study. In conclusion, this is the first report showing retarded elimination of dalteparin and enhanced free TFPI plasma levels induced by a LMWH in patients with renal insufficiency.

D2 dopamine receptor occupancy, risperidone plasma level and extrapyramidal motor symptoms in previously drug-free schizophrenic patients.

RATIONALE: A relationship between high D2 occupancy (above 80%) and extrapyramidal-motor symptoms under neuroleptic treatment has been observed in several neuroimaging studies. OBJECTIVES: We investigated the striatal dopamine D2 receptor occupancy, risperidone plasma level and extrapyramidal-motor symptoms in drug-free schizophrenic patients. METHODS: Ten schizophrenic patients were treated with 3 - 6 mg risperidone daily. After four weeks administration, a [(123)I]iodobenzamide ([(123)I]IBZM)-single photon emission tomography (SPET) scan for determination of D2 receptor occupancy was carried out (in eight responders) and compared to a control group. Plasma concentrations of risperidone and its active metabolite 9-hydroxyrisperidone (active moiety) were determined by high performance liquid chromatography and electrochemical detection. Extrapyramidal-motor symptoms were assessed by means of the Simpson-Angus-Scale and a handwriting test before treatment and coincident with the scan. RESULTS: The D2 receptor occupancy (Mean 62%, SD 13%) positively correlated with the plasma level of the risperidone active moiety as well as with the reduction in handwriting area. Multiple linear regression revealed an inherent relationship with a coefficient of determination of r = 0.956 (p = 0.02). No clinical relevant extrapyramidal-motor symptoms were observed. CONCLUSIONS: In drug-free schizophrenic responders, the simultaneous assessment of both plasma level and reduction in handwriting area may be a useful clinical tool for a surrogate estimate of D2 receptor occupancy under risperidone treatment. This may help to minimize or even prevent extrapyramidal-motor symptoms.

CYP3A4, CYP2C9 and CYP2B6 expression and ifosfamide turnover in breast cancer tissue microsomes.

Ifosfamide is a prodrug that requires bioactivation by cytochrome P450 for antitumour activity. Up to now, little is known, to what extent in addition to the liver the ifosfamide metabolism may occur intratumorally. For this purpose, we investigated the expression of CYP3A4, CYP2C9 and CYP2B6 in breast cancer tissue using Western Blotting. Ifosfamide turnover was determined by detection of metabolites of the ifosfamide 4-hydroxylation and N-dechloroethylation in tumour microsomal incubations using HPLC/UV and LC/MS. The results demonstrate that all mammary tumours (n=11) reveal CYP3A4 expression; contents varied from 0.5 to 63 pmol mg(protein)(-1). CYP2C9 (n=9) was present in all tested breast tumour samples, too, while CYP2B6 (n=10) protein could not be detected. All measured breast cancer microsomes (n=4) showed an ifosfamide N-dechloroethylation capacity in the range from 0.04 to 0.21 pmol min(-1) mg(protein)(-1), while metabolites of the 4-hydroxylation could not be determined. In conclusion, the detected presence of CYP3A4 and CYP2C9 in breast tumours offers the possibility of intratumoral turnover of ifosfamide. For the first time in the literature, we could demonstrate a turnover of ifosfamide by microsomal preparations from human breast cancer tissue. A calculated modulation of intratumoral ifosfamide turnover could considerably influence its therapeutic efficiency.

CYP2C and IL-6 expression in breast cancer.

Besides hepatic P450 (cytochrome P450) metabolism, there is increasing interest in the possibility of intratumoral activation of oxazaphosphorines by P450. Therefore, we investigated the expression of P450 (CYP2C8, CYP2C9, CYP2C18, and CYP2C19) by RT (reverse transcriptase)-polymerase chain reaction (PCR) and of CYP2C9 by Western blotting in 10 different breast tumor samples. Since P450 may be down regulated by interleukin (IL) IL-6, the receptor (R) for IL-6 was analyzed by RT-PCR and IL-6 in supernatants was calculated from ELISA data. None of the breast tumors was positive for CYP2C18 and CYP2C19 mRNA, whereas CYP2C8 and CYP2C9 were detected in all 10 breast tumors. Correspondingly, all breast tumors tested (9 of 10) revealed low, but nevertheless positive, staining of the CYP2C9 protein. All 10 samples were positive for the IL-6 receptor mRNA. ELISA measurement of IL-6 cytokine in supernatants revealed that all measured samples (8 of 10) were producing IL-6, the amounts ranging from 0.004 to 3.1 ng/g(tumor tissue). In summary, we have demonstrated that tumors of the breast express two out of four members of the CYP2C family, indicating that activation of such prodrugs as oxazaphosphorines may take place intratumorally. The presence of the IL-6 receptor and of IL-6 cytokine, which is produced in an autocrine manner, opens up the possibility that the well-known down regulating effect of IL-6 also takes place in breast tumors and might explain the weak or even absent expression of different CYP2C members.

Gender difference in ifosfamide metabolism by human liver microsomes.

Pharmacokinetic gender-dependent differences in cytochrome P450-mediated drug metabolism, especially CYP3A4, and their clinical implications are increasingly apparent. CYP3A4 seems to be the most important CYP isoform in both bioactivation and N-dechloroethylation of the alkylating prodrug ifosfamide, but informations about possible gender-related differences are lacking. Therefore we compared in 10 male and 10 female liver microsomal preparations the contents and activities of specific isoenzymes, involved in both metabolic pathways, especially CYP3A4, further CYP2A6, CYP2C9 and CYP2B6 and measured the in vitro activities of these microsomes in the ifosfamide 4-hydroxylation and N-dechloroethylation using high-sensitive HPLC/MS and -UV detection methods. Statistically significant differences between male and female livers were found in the mean CYP3A4 contents and activities. These differences had no consequences on the ifosfamide 4-hydroxylation activities of liver microsomes in vitro. In contrast, in the ifosfamide N-dechloroethylation reaction we found a statistically significant difference between the liver microsomes of male and female patients (0.13 +/- 0.05 nmol/min nmol P450 vs. 0.28 +/- 0.13 nmol/min x nmolP450, respectively). In conclusion, we firstly demonstrated such gender-related difference in the ifosfamide N-dechloroethylation, which could result in a higher risk of partly severe neurotoxic side effects in female patients.

Time-dependent inhibition of glioblastoma cell proliferation by dexamethasone.

Because of the outstanding importance of the glucocorticoid Dexamethasone (DEX) as supportive therapy in the management of brain tumours, the direct effect of DEX on tumour cell proliferation is of particular interest. Previous in vitro studies led to contradictory results. To characterise more precisely the influence of DEX, we investigated the glioblastoma multiforme (GM) cell lines A172, T98G and 86HG39. Cells were treated with DEX concentrations ranging from 5 x 10(-9) to 5 x 10(-5) M from 24 to 240h under different treatment conditions. Influence of DEX on glioma cell viability was assessed daily for 5 days by MTT-assay: (I) with continuous DEX incubation (acute treatment), (II) in a recultivation period without DEX after 5 days of DEX pre-incubation (pre-treatment), (III) with continuous DEX incubation after 5 days of DEX pre-incubation (combination treatment). DEX acute treatment led to strongly decreased proliferation of A172 cells, whereas T98G and 86HG39 cells remained uninfluenced. In opposite, a time-delayed inhibition of cell proliferation was observed in all three cell lines after DEX pre-treatment. Combination treatment induced a significant increase of the inhibitory effect in A172 and T98G cells. These data show a variable, partial time-dependent inhibitory effect of DEX on the proliferation of GM cells and may open new treatment strategies for malignant brain tumours.

In vitro tolerance to inhibition by ethanol of N-methyl-D-aspartate-induced depolarization in locus coeruleus neurons of behaviorally ethanol-tolerant rats.

Intracellular recordings were made in pontine slice preparations of the rat brain containing the locus coeruleus (LC). Ethanol at 100 mM, but not at 10 or 30 mM inhibited depolarizing responses to pressure-applied N-methyl-D-aspartate (NMDA) in LC neurons of ethanol-naive rats. Ethanol (100 mM) had a similar effect in LC neurons of ethanol-naive rats, of rats treated with ethanol for 14 days (3 g/kg daily, i.p.) and of rats treated with equicaloric amounts of saccharose (5 g/kg daily, i.p.). The blood concentration of ethanol was markedly decreased at 4 h, and was below the detection limit at 24 h after the last injection. Behavioral measurements in the open-field system demonstrated the development of tolerance in rats receiving ethanol for 14 days. Moreover, an anxiety-related reaction was shown to develop when the acute effect of the last ethanol injection vanished. Therefore, in subsequent in vitro experiments, ethanol (10 mM) was continuously present in the superfusion medium in order to mimic a steady blood concentration and to prevent a withdrawal-like situation. Under these conditions, ethanol (100 mM) still continued to inhibit the NMDA-induced depolarization in slices of untreated rats, but became ineffective in slices of ethanol-treated rats at 4 h after the last injection. By contrast, a supersensitivity to ethanol developed in brain slices at 24 h after the last ethanol injection. In conclusion, in vitro tolerance between systemically and locally applied ethanol at LC neurons could only be demonstrated when a low concentration of ethanol was added to the superfusion medium to simulate the blood concentration of this compound.

Pharmacokinetics of oral talinolol following a single dose and during steady state in patients with chronic renal failure and healthy volunteers.

OBJECTIVE: The objective of this study was to investigate the effect of renal impairment on the pharmacokinetics of the selective beta1-receptor antagonist talinolol. METHODS: Pharmacokinetic data were obtained in 12 healthy volunteers, 12 patients with renal impairment and 8 patients with terminal renal insufficiency after the oral administration of 100 mg talinolol and under steady state conditions (100 mg talinolol daily). Concentrations of talinolol in plasma, urine and dialysate during hemodialysis were measured with a validated HPLC-method. RESULTS: Talinolol is absorbed quite rapidly from the gastrointestinal tract (tmax 2.5-4 h). Steady state conditions were reached within 3-4 days depending on renal function. The calculated mean elimination half-life (t(1/2z)) in healthy volunteers (11 male, 1 female) was about 12 h. After an oral dose of 100 mg, about 55% of the bioavailable talinolol is eliminated unchanged in the urine. This fraction is reduced to 25% in patients with moderate to severe renal failure. A strong correlation was found between the renal elimination of talinolol and creatinine clearance. In patients with renal failure, the delayed elimination leads to an increase in t(1/2z) and to a decrease in the apparent total body clearance. Steady state trough levels (c(min)ss) in these patients are about 2.2-fold higher than in volunteers. The hemodialysability of talinolol was low. CONCLUSION: The disposition of talinolol shows a strong dependence on the renal function. On the basis of the kinetic data for talinolol, dose reductions of 30-50% are recommended in subjects with moderate to severe renal impairment.

IL-1 receptor type I expression in breast cancer.

The cytokine interleukin (IL)-1 is known to be involved in angiogenesis and metastasis. A prerequisite for IL-1 signalling is the presence of its receptor. Previously we have shown that glioblastoma cells express the IL-1 receptor type I (IL-1RI). In this study we analysed 11 breast tumour specimens for IL-1RI expression using the reverse transcriptase (RT) polymerase chain reaction (PCR). We found all the 11 breast tumours were positive for IL-1RI. This suggests that paracrine or autocrine produced IL-1 mediated signalling via IL-IRI might take place in breast tumours to control the production of pro-tumourigenic factors such as angiogenic factors and support further progression of tumour growth and metastasis.

Cyclophosphamide and related anticancer drugs.

This article presents an overview of the methods of bioanalysis of oxazaphosphorines, in particular, cyclophosphamide, ifosfamide, and trofosfamide as well as their metabolites. The metabolism of oxazaphosphorines is complex and leads to a large variety of metabolites and therefore the spectrum of methods used is relatively broad. The various methods used are shown in a table and the particularly important assays are described.

Modulation of multidrug resistance in human leukemia cells with mdr1-targeted antisense oligonucleotides using variable treatment schedules.

OBJECTIVE: The purpose of the current study was to characterize the effect of chimeric AS-ODNs encapsulated with cationic lipids on MDR in human leukemia cells and to determine if this modification of the ODN alone or in combination with the cationic lipid might offer advantages over classical ODN treatment with free unmodulated or phosphorothiolated AS-ODNs. Furthermore, we extended the antisense method to the use of AS-ODNs in the parental drug-sensitive leukemia cells which express mdr1-mRNA at a relative low level and lack P170 expression to evaluate the effectiveness of prophylactic AS-ODN treatment. METHODS: The effect of a 4-day AS-ODN treatment in drug-resistant human leukemia cells which exhibit the classic MDR phenotype at a moderate level was examined. Twenty-four hours after the last ODN administration the cells were analyzed for mdr1-mRNA (quantitative RT-PCR) and P170 expression (FCM), for R123 accumulation/efflux capacity (FCM) and for sensitivity to vincristine (MTT). In the parental drug-sensitive CCRF-CEM cells the mdr1-mRNA expression was assessed 24, 48 and 72 h after AS-ODN treatment administered as free phosphorothioate or conjugated with DMRIE-C. RESULTS: Cationic lipids produced a clear increase in cellular ODN uptake but also caused an increase in variability of uptake rates (30% vs. 10% variability after free phosphorothioates). Both AS-ODNs inhibit P170 expression whereby the antisense effect of the chimeric ODN seems to be stronger compared to the phosphorothioate (30% vs. 22% MRK16 staining). Consistent with the inhibition of P170 expression, an increased sensitivity to vincristine was observed. In parental drug-sensitive cells, AS-ODN treatment caused nearly complete inhibition of mdr1-mRNA expression (5% of control). CONCLUSION: The data demonstrate that it is nearly impossible to achieve a complete reversal of the MDR phenotype in drug-resistant cells using AS-ODNs. A more promising approach seems to be the prophylactic treatment with AS-ODNs.