Hypophosphatasia as a rare cause of neonatal seizures.

Severe forms of hypophosphatasia due to loss-of-function in the ALPL gene may present with diverse neurological problems including pyridoxine-responsive seizures. We present a short report of pyridoxine-responsive neonatal seizures. Due to severe osteopenia with unmeasurable levels of alkaline phosphatase, targeted genetic screening was performed and two pathogenic variants in the gene for the nonspecific alkaline phosphatase confirmed the diagnosis of hypophosphatasia. We would like to emphasize the importance of considering infantile hypophosphatasia in the differential diagnosis of pyridoxine-responsive seizures with concomitant low alkaline phosphatase level and bone pathology, especially with the new treatments becoming available in the future.

Movement and vocal intonation together evoke social referencing in companion dogs when confronted with a suspicious stranger.

Dogs have been claimed to engage in social referencing by responding in a way that corresponded with their owners' reaction in some contexts. We aimed to assess how owners' actions affect family dogs' behaviour in two ambiguous lifelike situations. In Experiment 1, two groups were tested; in the suspicious owner (SO) group, owners behaved suspiciously (N = 25), in the reassuring owner (RO) group, owners behaved in a reassuring manner (N = 28) facing a 'threatening stranger'. The sitting owners provided voice intonation and body posture changes as cues for the dogs when the stranger entered the room. Dogs looked longer at the owners and stayed longer near them in the SO group but their tendency to approach the stranger did not differ between the groups. Although the owners' behaviours seemed to have relevant effects on dogs' responses, we note that these looking and proximity seeking behaviours might also be explained by reactions to the owners' behaviour alone. In Experiment 2, all dogs (N = 19) were tested in both the SO and RO conditions in a slightly different procedure. Depending on the condition, owners took one step forward/backward and spoke happily/worryingly. The procedural differences and the larger distance between the stranger and the owner allowed the dog more time to perceive the behaviour of both the stranger and the owner, which made the distinction between alternative explanations for the dogs' behaviour easier to interpret. Dogs spent more time behind their owners in the SO condition and more dogs approached the stranger in the RO condition. Dogs' avoidance of the stranger when the owner behaved suspiciously and their tendency to approach the stranger only when the owner displayed positive emotions, can be best explained by social referencing.

Symmetrical Thalamic Lesions in the Newborn: A Case Series.

Although bilateral injury to the thalami is often seen in (near)term infants with hypoxic ischemic encephalopathy (HIE), symmetrical thalamic lesions (STL) is a different, very rare condition, seen both in full-term and preterm infants often after an antenatal insult, although the history is not always clear. These lesions are usually first detected using cranial ultrasound (cUS). They may not always be seen on the first (admission) scan, but become apparent in the course of the 1st week after birth. Clinically, these infants present with hypo- or hypertonia, absence of sucking and swallowing reflexes, and they may have contractures and facial diplegia. Neuropathology commonly demonstrates a thalamic lesion with additional and variable involvement of basal ganglia and brainstem. The prognosis is very poor, the condition often leads to severe disabilities and/or death within the first years of life. The clinical course and neuroimaging findings of 13 patients with symmetrical thalamic lesions (STL) are reported.

Detecting and quantifying activity/inflammation in localized scleroderma with thermal imaging.

BACKGROUND: The disease phase in localized scleroderma (LoS) is commonly assessed by clinical investigation using the LoS cutaneous assessment tool (LoSCAT). There is a need for more objective methods for assessing the degree of activity/inflammation in LoS. The aim of our work was to evaluate the correlation between severity of the LoS lesions scored using LoSCAT and the degree of hyperthermia observed with infrared thermography (IRT). MATERIALS AND METHODS: The LoS lesions were examined using the LoSCAT and IRT independently by two examiners. The average temperature (Tavg) of the LoS lesional dermis were measured in the area of each lesion with the highest score for erythema (ER), skin thickness (ST), dermal atrophy (DAT) and subcutaneous atrophy (SAT). Measurements were compared to the contralateral healthy skin. The difference of the Tavg (ΔTavg) was calculated between each lesion and its normal control. RESULTS: One hundred and four LoS lesions were examined in 40 adults. Thirty-one lesions were erythematous, 26 were sclerotic, 35 presented as atrophy of the dermis and 11 as atrophy of the subcutaneous tissue. The sensitivity and specificity of IRT for detecting activity/inflammation were 80.7% and 86.3%, respectively. The positive predictive value was 71%, negative predictive value 91%. Statistically significant positive correlation was found between the ΔTavg and the clinical ER and DAT scores. CONCLUSION: IRT may be a useful method for assessing erythematous LoS lesions and quantifying the degree of activity/inflammation. Knowing the patient, false positive results attributable to more severe degree of skin and subcutaneous fat atrophy can be easily recognized.

Elimination of Doripenem during Dialysis and Pharmacokinetic Evaluation of Posthemodialysis Dosing for Patients Undergoing Intermittent Renal Replacement Therapy.

Doripenem is a broad-spectrum parenteral carbapenem with enhanced activity against Pseudomonas aeruginosa and Enterobacteriaceae Current dosing regimens recommend the administration of 0.25 to 0.5 g once daily in patients undergoing intermittent renal replacement therapy. As patients are usually dialyzed thrice weekly, we aimed to investigate a 1-g posthemodialysis regimen, thus reducing treatment costs and enhancing patient compliance. A second objective of this trial was to describe the pharmacokinetics of intradialytic doripenem. Ten oliguric or anuric patients in need of intermittent renal replacement therapy were included in this trial. All patients suffered from a septic episode. The mean hemofilter clearance was 123.46 ± 42.03 ml/min, and the total body clearance between hemodialysis sessions was 16.79 ± 6.02 ml/min. The average prehemodialysis trough concentration was 2.4 ± 1.3 mg/liter, while the EUCAST resistance breakpoint for Enterobacteriaceae is set at 2 mg/liter. The interpatient variability was considerably higher than the intrapatient variability. Apart from one patient who suffered an allergic reaction, doripenem was tolerated well by all patients. Our data indicate that posthemodialysis administration of 1 g of doripenem results in sufficient plasma levels in anuric but not oliguric patients during the entire dosing interval. (This trial was registered with EudraCT under registration no. 2009-018010-18 and at ClinicalTrials.gov under registration no. NCT02018939.).

Micafungin Plasma Levels Are Not Affected by Continuous Renal Replacement Therapy: Experience in Critically Ill Patients.

Critically ill patients often experience acute kidney injury and the need for renal replacement therapy in the course of their treatment in an intensive care unit (ICU). These patients are at an increased risk for candidiasis. Although there have been several reports of micafungin disposition during renal replacement therapy, to this date there are no data describing the elimination of micafungin during high-dose continuous venovenous hemodiafiltration with modified AN69 membranes. The aim of this prospective open-label pharmacokinetic study was to assess whether micafungin plasma levels are affected by continuous hemodiafiltration in critical ill patients using the commonly employed AN69 membrane. A total of 10 critically ill patients with micafungin treatment due to suspected or proven candidemia were included in this trial. Prefilter/postfilter micafungin clearance was measured to be 46.0 ml/min (±21.7 ml/min; n = 75 individual time points), while hemofilter clearance calculated by the sieving coefficient was 0.0038 ml/min (±0.002 ml/min; n = 75 individual time points). Total body clearance was measured to be 14.0 ml/min (±7.0 ml/min; n = 12). The population area under the curve from 0 to 24 h (AUC0-24) was calculated as 158.5 mg · h/liter (±79.5 mg · h/liter; n = 13). In spite of high protein binding, no dose modification is necessary in patients receiving continuous venovenous hemodiafiltration with AN69 membranes. A dose elevation may, however, be justified in certain cases. (This study has been registered at ClinicalTrials.gov under identifier NCT02651038.).

Localized scleroderma: clinical and epidemiological features with emphasis on adulthood- versus childhood-onset disease differences.

BACKGROUND: Localized scleroderma is a rare inflammatory skin disorder that affects the skin and sometimes underlying subcutaneous tissue, muscles or bones. The disease has two modes of onset: juvenile- (JLS) and adult-onset (aLoS). Clinical features have impact on diagnostic and treatment recommendations, but no consensus on the disease management depending on the age at diagnosis was given. OBJECTIVE: To identify these features which differentiate aLoS from JLS. METHODS: A review of the literature was carried out using the MEDLINE to identify studies assessing demographics, subtype distribution, extracutaneous manifestations, comorbidities, delay at diagnosis and outcome in JLS and aLoS. Non-English articles, reviews, case reports, treatment trials that did not investigate long-term outcomes and studies with the fused data for children and adults were excluded. The analysed papers were published between June 1986 and December 2016. RESULTS: Fifty-five studies describing JLS or/and aLoS were included for analysis. Female: male ratio in aLoS was higher than in JLS. Adults presented with plaque and generalized subtype more often than paediatric patients. Linear subtype, musculoskeletal, neurologic and ophthalmologic involvement were more frequent, among children. aLoS was likely to be associated with increased prevalence of lichen sclerosus. There was significant delay in diagnosis in both groups of patients. Recurrences of disease were independent of its onset mode. aLoS patients had more poor quality of life scores than did JLS patients. As only a few studies or no studies assessing specified disease subtypes were identified, this limited the ability to compare the adult and paediatric patients with these subtypes. CONCLUSION: Despite more favourable course of aLoS, a thorough understanding of the broad spectrum of domains related to physical, mental, emotional and social functioning of patients seems to be important to the proper management of disease. LoS heterogeneity makes it important to develop universal classification criteria.

A systematic review of tools for determining activity of localized scleroderma in paediatric and adult patients.

Localized scleroderma (LoS) is a rare inflammatory skin disorder that affects the dermis and sometimes subcutaneous tissues. LoS can have very long periods of quiescence followed by reactivation, but the progression or activity of the disease is difficult to measure. To review the measuring tools used for the evaluation of LoS activity, to choose the most appropriate technique to facilitate progress towards properly assessing the disease, a systematic review of the literature was carried out using the PubMed MEDLINE. Sixty-three studies describing groups of children, adults or both were reviewed and included in the analysis. Case reports were excluded. The analysed papers were published between June 1986 and February 2016. Data were extracted with a focus on instruments measuring the clinical signs of LoS, health-related quality of life (HRQoL), laboratory tests and imaging techniques. Perusal of the literature confirmed that clinical characteristics of the lesions were used to identify activity and scoring systems that focused on a series of signs, and were initially validated in cases of childhood-onset disease; however, there were no data concerning the adult-onset form of the disease. Adult patients with LoS scored lower on HDLQI than those with paediatric-onset LoS. No validated biological markers were available as correlative laboratory parameters of LoS activity. For infrared thermography, ultrasound and other imaging techniques, the features of active lesions were described, but were only useful with appropriate clinical correlation. Measuring tools have not been prospectively validated yet. Summarizing, scoring methods seem to provide the most adequate assessment of LoS and deserve to be further investigated. Combined imaging techniques create optimal conditions for the proper interpretation of the temperature at the skin surface, as well as the structure and vascularity of LoS lesions. Additional scores, musculoskeletal or neuroimaging techniques and laboratory parameters are needed for the specific disease subtypes to monitor extracutaneous manifestations.

Pilot PET Study to Assess the Functional Interplay Between ABCB1 and ABCG2 at the Human Blood-Brain Barrier.

ABCB1 and ABCG2 work together at the blood-brain barrier (BBB) to limit brain distribution of dual ABCB1/ABCG2 substrates. In this pilot study we used positron emission tomography (PET) to assess brain distribution of two model ABCB1/ABCG2 substrates ([(11) C]elacridar and [(11) C]tariquidar) in healthy subjects without (c.421CC) or with (c.421CA) the ABCG2 single-nucleotide polymorphism (SNP) c.421C>A. Subjects underwent PET scans under conditions when ABCB1 and ABCG2 were functional and during ABCB1 inhibition with high-dose tariquidar. In contrast to the ABCB1-selective substrate (R)-[(11) C]verapamil, [(11) C]elacridar and [(11) C]tariquidar showed only moderate increases in brain distribution during ABCB1 inhibition. This provides evidence for a functional interplay between ABCB1 and ABCG2 at the human BBB and suggests that both ABCB1 and ABCG2 need to be inhibited to achieve substantial increases in brain distribution of dual ABCB1/ABCG2 substrates. During ABCB1 inhibition c.421CA subjects had significantly higher increases in [(11) C]tariquidar brain distribution than c.421CC subjects, pointing to impaired cerebral ABCG2 function.

Doripenem Treatment during Continuous Renal Replacement Therapy.

Doripenem is a broad-spectrum parenteral carbapenem with enhanced activity against Pseudomonas aeruginosa. While the initial dosing recommendation for renally competent patients and patients undergoing continuous renal replacement therapy (cRRT) was 500 mg every 8 h (q8h), the dose for renally competent patients was updated to 1 g q8h in June 2012. There are no updated data for the dosing of patients on continuous renal replacement therapy. The original dosing regimen for cRRT patients was based on nonseptic patients, while newer publications chose comparatively low target concentrations for a carbapenem. Thus, there is an urgent need for updated recommendations for dosing during cRRT. In the trial presented here, we included 13 oliguric septic patients undergoing cRRT in an intensive care setting. Five patients each were treated with hemodiafiltration or hemodialysis, while three patients received hemofiltration treatment. All patients received 1 g doripenem every 8 h. Doripenem concentrations in the plasma and ultrafiltrate were measured over 48 h. The mean hemofilter clearance was 36.53 ml/min, and the mean volume of distribution was 59.26 liters. The steady-state trough levels were found at 8.5 mg/liter, with no considerable accumulation. Based on pharmacokinetic and pharmacodynamic considerations, we propose a regimen of 1 g q8h, which may be combined with a loading dose of 1.5 to 2 g for critically ill patients. (This study has been registered with EudraCT under registration no. 2009-018010-18 and at ClinicalTrials.gov under registration no. NCT02018939.).

Early clinical remission and normalisation of CRP are the strongest predictors of efficacy, mucosal healing and dose escalation during the first year of adalimumab therapy in Crohn's disease.

BACKGROUND: Adalimumab is a fully human monoclonal antibody targeting tumour necrosis factor with proven efficacy in the treatment of Crohn's disease (CD). AIM: To investigate the predictors of medium-term clinical efficacy and mucosal healing during adalimumab therapy, in patients with CD, in specialised centres approved for biological therapy in Hungary. METHODS: Data capture of the 201 CD patients was standardised and prospective (male/female: 112/89, median age: 33.0 years, duration: 8 years). Previous infliximab therapy had been administered in 48% of patients, concomitant steroids in 41%, azathioprine in 69% and combined therapy in 27% of patients. RESULTS: Overall clinical response and remission rates at 24 weeks were 78% and 52%, respectively; at 52 weeks were 69% and 44%, respectively. Endoscopic improvement and healing were achieved in 43% and 24% of patients. In a logistic regression model, clinical efficacy and CRP at week 12, need for combined immunosuppression at induction, shorter disease duration and smoking were identified as independent predictors for 12-month clinical outcome, whereas CRP at week 12, clinical remission at week 24, inflammatory parameters and nonsmoking were associated to endoscopic improvement/healing. Intensification to weekly dosing was needed in 16% of patients. Parallel azathioprine therapy and clinical remission at week 12 were inversely associated with dose escalation. CONCLUSIONS: Clinical efficacy and normalised CRP at week 12 (early deep clinical remission) are associated with medium-term clinical efficacy and mucosal healing during adalimumab therapy, whereas need for combined immunosuppression at induction and smoking status are predictors for non-response. Parallel azathioprine therapy may decrease the probability for dose escalation.

Proteolytic resistance conferred to fibrinogen by von Willebrand factor.

The formation of platelet-rich thrombi under high shear rates requires both fibrinogen and von Willebrand factor (VWF) as molecular adhesives between platelets. We attempted to describe the role of VWF as a potential substrate and modulator of the fibrinolytic system using binding assays, as well as kinetic measurements on the cleavage of fibrin(ogen) and a synthetic plasmin substrate (Spectrozyme-PL). The similar dissociation constants for the binding of plasminogen, plasmin, and active site-blocked plasmin onto immobilised VWF suggest that the primary binding site in plasmin(ogen) is not the active site. The progressive loss of clottability and generation of degradation products during fibrinogen digestion with plasmin were delayed in the presence of VWF at physiological concentrations, while VWF cleavage was not detectable. Determination of kinetic parameters for fibrinogen degradation by plasmin, miniplasmin and microplasmin showed that VWF did not modify the Km, whereas kcat values decreased with increasing VWF concentrations following the kinetic model of non-competitive inhibition. Inhibitory constants calculated for VWF were in the range of its physiological plasma concentration (5.4 mg/ml, 5.7 mg/ml and 10.0 mg/ml for plasmin, miniplasmin and microplasmin, respectively) and their values suggested a modulating role of the kringle 5 domain in the interaction between VWF and (mini)plasmin. VWF had no effect on the amidolytic activity of plasmin on Spectrozyme-PL, or on fibrin dissolution by (mini)plasmin. Our data suggest that VWF, while a poor plasmin substrate relative to fibrinogen, protects fibrinogen against degradation by plasmin preserving its clottability in plasma and its adhesive role in platelet-rich thrombi.

Sulfation of resveratrol in human liver: evidence of a major role for the sulfotransferases SULT1A1 and SULT1E1.

Sulfation of resveratrol, a polyphenolic compound present in grapes and wine with anticancer and cardioprotective activities, was studied in human liver cytosol. In the presence of 3'-phosphoadenosine-5'-phosphosulfate, three metabolites (M1-3) whose structures were identified by mass spectrometry and NMR as trans-resveratrol-3-O-sulfate, trans-resveratrol-4'-O-sulfate, and trans-resveratrol-3-O-4'-O-disulfate, respectively. The kinetics of M1 formation in human liver cytosol exhibited an pattern of substrate inhibition with a K(i) of 21.3 +/- 8.73 microM and a V(max)/K(m) of 1.63 +/- 0.41 microLmin(-1)mg(-1) protein. Formation of M2 and M3 showed sigmoidal kinetics with about 56-fold higher V(max)/K(m) values for M3 than for M2 (2.23 +/- 0.14 and 0.04 +/- 0.01 microLmin(-1)mg(-1)). Incubation in the presence of human recombinant sulfotransferases (SULTs) demonstrated that M1 is almost exclusively catalysed by SULT1A1 and only to a minor extent by SULT 1A2, 1A3 and 1E1, whereas M2 is selectively formed by SULT1A2. M3 is mainly catalysed by SULT1A2 and 1A3. In conclusion, the results elucidate the enzymatic pathways of resveratrol in human liver, which must be considered in humans following oral uptake of dietary resveratrol.

Characterisation of cellobiose dehydrogenases from the white-rot fungi Trametes pubescens and Trametes villosa.

Cellobiose dehydrogenase (CDH) is an extracellular haemoflavoenzyme that is produced by a number of wood-degrading and phytopathogenic fungi and it has a proposed role in the early events of lignocellulose degradation and wood colonisation. In the presence of a suitable electron acceptor, e.g. 2,6-dichloro-indophenol, cytochrome c, or metal ions, CDH oxidises cellobiose to cellobionolactone. When screening 11 different Trametes spp. for the formation of CDH activity, all the strains investigated were found to secrete significant amounts of CDH when cultivated on a cellulose-containing medium. Amongst others, Trametes pubescens and Trametes villosa were identified as excellent, not-yet-described, producer strains of this enzyme activity that has various potential applications in biotechnology. CDH from both strains was purified to apparent homogeneity and subsequently characterised. Both monomeric enzymes have a molecular mass of approximately 90 kDa (gel filtration) and a pI value of 4.2-4.4. The best substrates are cellobiose and cellooligosaccharides; additionally, lactose, thiocellobiose, and xylobiose are efficiently oxidised. Glucose and maltose are poor substrates. The preferred substrate is cellobiose with a Km value of 0.21 mM and a kcat value of 22 s(-1) for CDH from T. pubescens; the corresponding values for the T. villosa enzyme are 0.21 mM and 24 s(-1), respectively. Both enzymes showed very high activity with one-electron acceptors such as ferricenium, ferricyanide, or the azino-bis-(3-ethyl-benzthiazolin-6-sulfonic acid) cation radical.

Metabolism and disposition of the novel antileukaemic drug, benzamide riboside, in the isolated perfused rat liver.

Benzamide riboside (BR) is a novel anticancer agent exhibiting pronounced activity against several human tumor cells, however, little is known about its biotransformation. To analyze for BR and its metabolites, livers of Wistar and mutant TR- rats were perfused with BR in a single pass system. In bile, native BR and its deamination product, benzene carboxylic acid riboside (BR-COOH) was quantified by HPLC. Total excretion of BR and BR-COOH into bile of Wistar rats was low (< 0.2%) whereas cumulative efflux of BR and its metabolite BR-COOH was high, representing 79% and 1.6% of infused BR, respectively. Biliary excretion of BR and BR-COOH in TR- rats, deficient in canalicular multispecific organic anion transporter, a membrane protein identical to MRP2 in tumor cells, was only slightly lower than in Wistar rats, indicating that BR and BR-COOH are non-substrates of MRP2. Experiments using rat hepatocytes incubated with BR did show a linear uptake of BR and a subsequent metabolism to BR-COOH that was largely excreted into the cellular supernatant. Examination of the cytotoxic activity against the human HL60 and K562 leukemia cells in a clonogenic assay demonstrated an IC50 of 619 microM and 1013 microM for BR-COOH compared to the IC50 of 0.21 microM and 0.46 microM for BR, suggesting the inertness of the metabolite. In summary, we found that deamination of BR to BR-COOH is the main metabolic pathway in rat liver. BR-COOH formation should also be considered in human liver during cancer therapy.

Differential expression of cytokines and cytokine receptors in renal cell carcinoma.

Modulation of immunomechanisms by tumor cells can be caused by secretion of cytokines. In vitro data are usually gained in culture systems. It is debatable whether these systems are representative of the conditions inside the respective tumor tissues. Immunohistochemical studies of tumor tissue cryostats were compared with those in matched primary renal cell carcinoma tumor cell cultures. Results were correlated with histopathological characteristics and the in vitro cytotoxic effect of autologous tumor infiltrating lymphocytes (TILs). Expression of all studied cytokines and cytokine receptors could be shown in cryostats and cell cultures, but the detection pattern varied individually. The immunohistochemical results in cryostats were in good accordance with those in cell cultures. Expression of TGFbeta1 both in cryostats and cell cultures significantly correlated with the lack of cytotoxic activity of autologous TILs. Representative data can be obtained in tumor culture systems of primary renal cell carcinoma. TGFbeta1 secretion could play an important role in the interactions between tumor and cytotoxic cells.

In vitro glucuronidation of the cyclin-dependent kinase inhibitor flavopiridol by rat and human liver microsomes: involvement of UDP-glucuronosyltransferases 1A1 and 1A9.

The metabolism of flavopiridol (FLAP), a novel anticancer drug currently undergoing clinical development, was investigated in rat and human liver microsomes. In the presence of uridine 5'-diphosphoglucuronic acid, two biotransformation products (M1 and M2) could be detected. Formation of metabolite M1 and M2 in terms of enzymatic efficacy (Vmax/K(M)) was about 50- and 5-fold higher in rat (1.58 +/- 2.23 and 7.22 +/- 1.17 microl/min/mg) as compared with human liver microsomes (0.032 +/- 0.016 and 1.52 +/- 0.93 microl/min/mg), indicating species-related differences in FLAP glucuronidation. Incubation in the presence of human recombinant UDP-glucuronosyltransferases (UGTs) demonstrated that M1 is almost exclusively catalyzed by UGT1A1, whereas M2 is formed by UGT1A9 and only to a minor extent by UGT1A1 and UGT1A10. Chemical inhibition experiments further prove the involvement of UGT1A1 and UGT1A9 in the formation of M1 and M2, as the UGT1A1 substrate bilirubin preferably inhibited M1 over M2 (K(i): 36 and 258 microM, respectively), whereas the UGT1A9 substrate propofol showed a more pronounced decrease in M2 but not in M1 formation (K(i): 47 and 142 microM, respectively). Both conjugates were purified from rat liver microsomes and analyzed by mass spectrometry, NMR, and UV experiments. On the basis of these results, M1 was identified as 5-O-beta-glucopyranuronosyl-flavopiridol and M2 as 7-O-beta-glucopyranuronosyl-flavopiridol. In conclusion, our results elucidate the enzymatic pathways of FLAP in rat and human liver, which must be considered during cancer therapy of patients.

Metabolism of the new ribonucleotide reductase inhibitor amidox in the isolated perfused rat liver.

BACKGROUND: Amidox (AX) is a novel anticancer drug currently undergoing pre-clinical studies. Though AX shows activity against various tumor cells, its biotransformation is still unknown. MATERIAL AND METHODS: Livers of male Wistar and mutant TR- rats were perfused with AX in a single pass system and bile and effluent perfusate analyzed by HPLC for AX and its metabolites. RESULTS: In bile, seven biotransformation products but not AX could be quantified though their total excretion into bile was low. However, the cumulative efflux of AX metabolites into the effluent perfusate was high with about 55% of AX applied to the liver during perfusion. Biliary excretion of AX metabolites in TR- rats was substantially reduced compared to Wistar rats, indicating that metabolites are substrates of the canalicular multispecific organic anion transporter cmoat. CONCLUSION: Metabolism of AX in rat liver is high and has to be considered during cancer therapy of patients.