High 6-thioguanine nucleotide levels and low thiopurine methyltransferase activity in patients with lupus erythematosus treated with azathioprine

Azathioprine (AZA) is characterized by a high interindividual variability in bioavailability and metabolism. AZA is converted into 6-thioguanine nucleotides (6-TGN) to which the immune modifier activity is attributed. The 6-TGN levels are known to be affected by the activity of the key enzyme, thiopurine methyltransferase (TPMT), which is under genetic dependence. The authors measured a significantly lower TPMT activity in 53 women with systemic lupus erythematosus (SLE) (12.2 +/- 2.4 pmol/h/ml RBC; P < 0.01) when compared with 30 healthy control participants (13.15 +/- 3.1 pmol/h/ml RBC) but not with 28 patients with other dysimmune diseases (non-SLE; 13.0 +/- 3.0 pmol/h/ml RBC; P = 0.10). To evaluate the impact of TPMT activity on the concentrations of AZA metabolites, we measured the TPMT activity and 6-TGN levels in a subgroup of 26 patients in remission and treated with a stable dose of AZA (mean value: 1.9 +/- 0.5 mg/kg/day) for at least six months (n = 13 with SLE and n = 13 with other dysimmune diseases, ie, non-SLE). In such a subgroup, no correlation between 6-TGN levels and TPMT activity was observed. However, patients with SLE presented lower TPMT activity and higher 6-TGN levels (215 +/- 123 versus 140 +/- 75 pmol/8 x 10(8) RBC in non-SLE patients; P < 0.04). It must be noted that transient increase in 6-methylmercaptopurine levels (6-MMP), a putative toxic metabolite (up to 21.7 nmol/8 x 10(8) RBC), was more frequently observed in the non-SLE group (P < 0.01). Even if a relationship was observed between low TPMT activity and 6-TGN levels in SLE, its clinical impact appears to be limited as far as regular hematologic controls are performed.

The surgical management of congenital liver cysts

BACKGROUND

Most series that report the results of surgical treatment for congenital liver cysts focus more on the technical aspects of the operation than on the late outcome of these patients. In this paper, we emphasize the importance of appropriate patient selection and adequate surgical technique for successful long-term outcome.

METHODS

Twenty-four consecutive patients with congenital liver cysts were selected for surgical treatment. According to our own classification, 13 patients had simple liver cysts, nine had multicystic liver disease, and two had type I polycystic liver disease. All of these patients were treated by the fenestration technique. An open approach was used for five patients (group 1) treated between 1984 and 1990. In 19 patients (group 2) treated since 1991, a laparoscopic approach was used. The incidence of complicated liver cysts was 40% in group 1 and 68% in group 2.

RESULTS

There were no treatment-related deaths in this series. The mean postoperative hospital stay was significantly shorter for patients who underwent successful laparoscopic fenestration (p < 0.05). In the open group (group 1), there were no postoperative complications, and all patients were alive and free of symptoms during a mean follow-up of 130 months, without any sign of cyst recurrence. In the laparoscopic group (group 2), four patients were converted to open surgery. One of these patients had an inaccessible posterior cyst; another had bile within the cystic cavity. A further two cases had complicated liver cysts with an uncertain diagnosis between congenital and neoplastic cysts. Four patients (21%) developed peri- or postoperative complications. During a mean follow-up time of 38.5 months, none of the patients with simple liver cysts incurred late symptoms or signs of cyst recurrence. In the six patients with multicystic liver disease, one developed disease-related cyst progression (17%) and required reoperation. One of the two patients with type I polycystic liver disease (50%) developed asymptomatic disease-related cyst progression.

CONCLUSIONS

When patients are carefully selected and a proper surgical technique is employed, excellent long-term results with a low morbidity rate can be achieved in patients with congenital liver cysts. Patients with multicystic liver disease or type I polycystic liver disease are more prone to late cyst recurrence. A tailored approach is thus indicated for patients with congenital liver cystic disease. However, the laparoscopic approach appears to be the gold standard for the treatment of highly symptomatic or complicated simple liver cysts.

Immunolocalisation of cytochrome P-450 3A enzymes in human breast carcinoma: relationship with tumour differentiation and steroid receptors

Cytochrome P-450 3A enzymes belong to the most abundant subfamily of the cytochrome P-450 system. They are predominantly found in the liver where they metabolize numerous drugs and endogenous substances such as oestrogens. However, they are also expressed by normal and tumoural extrahepatic tissues. Accordingly, immunolocalization was assessed in malignant breast tumours (n=32) and normal counterparts, by using a monoclonal antibody that recognizes all human CYP3A proteins. We investigated a potential relation between expression of CYP3A protein expression, the degree of tumour differentiation assessed by the histological grade and the proliferation index assessed by Ki-67 immunostaining. Immunodetection of CYP3A was observed in 27 of the 32 tumours analyzed (84%). A focal staining was also observed in the adjacent normal breast tissue in 33% of the samples, but expression was always fainter than in tumours. A significant negative association was found between CYP3A and the proliferation index, but there was no relation with receptor status or tumour differentiation. While CYP3A protein expression can be found in normal breast tissues, these data highlight higher and more frequent CYP3A in malignant breast cells. Such expression in malignant breast cells appears inversely related to the proliferation index whereas no relation is found with tumour differentiation.

Hepatic perfusion parameters in chronic liver disease: dynamic CT measurements correlated with disease severity

OBJECTIVE

The aim of our study was to determine if hepatic perfusion parameters measured with CT change in relation to disease severity in patients with chronic liver disease.

SUBJECTS AND METHODS

Dynamic contrast-enhanced single-section CT scans of the liver were obtained in 40 individuals who included six control subjects, 16 patients with noncirrhotic chronic liver disease, and 18 patients with cirrhosis. Hepatic, aortic, and portal venous time-density curves were fitted to a dual-input one-compartment model to calculate the liver perfusion, arterial fraction, distribution volume, and mean transit time.

RESULTS

Liver perfusion decreased in patients with cirrhosis (67 +/- 23 mL. min(-1). 100 mL(-1) versus 108 +/- 34 mL. min(-1). 100 mL(-1) in control subjects [p = 0.009] and 98 +/- 36 mL. min(-1). 100 mL(-1) in patients with noncirrhotic chronic liver disease [p = 0.003]), and the arterial fraction and the mean transit time increased (41 +/- 27% and 51 +/- 79 sec versus 17 +/- 16% and 16 +/- 5 sec in control subjects, and 19 +/- 6% and 17 +/- 8 sec in patients with noncirrhotic chronic liver disease [p < 0.05]). A significant correlation was seen between these three perfusion parameters and the severity of chronic liver disease based on clinical and biologic data (p < 0.001). No significant change in distribution volume was observed.

CONCLUSION

Hepatic perfusion parameters measured with CT were significantly altered in cirrhosis and correlated with the severity of chronic liver disease.

Therapeutic drug monitoring of azathioprine and 6-mercaptopurine metabolites in Crohn disease

BACKGROUND

6-Mercaptopurine (6-MP) and its prodrug azathioprine (AZA) have proven efficacy in the treatment of Crohn disease (CD). The immunosuppressive properties of AZA/6-MP are mediated by the intracellular metabolism of 6-MP into its active metabolites, 6-thioguanine nucleotides (6TGN) and 6methylmercaptopurine (6-MMP). Preliminary studies have suggested that the red blood cell concentration of 6TGN (RBC 6TGN) is a potential guide to therapy. The aims of the study were to evaluate the RBC 6TGN concentrations in adult patients with CD under long-term AZA/6-MP therapy and to correlate it with response to treatment and haematological parameters.

METHODS

Twenty-eight CD patients treated for at least 3 months with AZA/6-MP were prospectively studied. Patients were separated into three main groups: group 1 (n = 19), corresponding to quiescent CD receiving AZA (dose: 2.05 +/- 0.4 mg/kg/day for a mean of 28.6 +/- 25 months) or 6-MP (dose: 1.4 +/- 01 mg/kg/day for a mean of 7.5 +/- 3.5 months) alone; group 2 (n = 6), corresponding to quiescent CD treated by AZA (dose: 2.14 +/- 0.5 mg/kg/day for a mean of 29.5 +/- 22 months) with oral steroids; and group 3 (n = 3), corresponding to active CD on AZA (dose: 1.94 +/- 0.6 mg/kg/day for a mean of 31.3 +/- 35 months) as the only treatment. An assessment was also made by merging groups 1 and 2 forming a larger group of patients (n = 25) defined by clinical remission and groups 2 and 3 forming a larger group of patients (n = 9), non-complete responders with AZA/6-MP alone. Crohn disease index activity (CDAI), blood samples for full blood count and differential white cell count and measurement of RBC 6TGN and 6-MMP concentrations were evaluated at inclusion and at 6 months (n = 17). RBC 6TGN were measured using high performance liquid chromatography (HPLC) on heparinized blood.

RESULTS

The baseline characteristics of the three groups of patients were similar. There was no significant difference among the three groups of patients regarding the dose and the duration of immunosuppressive treatment. There was no significant difference between groups according to various parameters tested. Particularly, the median RBC 6TGN concentration at inclusion was similar in the three groups of patients (166 (105-688), 183 (90-261) and 160 (52-194) pmol/8 x 10(8) RBC, respectively). The majority of patients had no detectable level of 6-MMP metabolite, except for 3 patients. There was also no difference between merging groups. Furthermore, there was no significant correlation between RBC 6TGN concentrations and the various biological parameters tested except for the mean erythrocyte volume. At 6 months, all patients of group 1 remained in remission and median RBC 6TGN concentration remained stable. No side effects were observed.

CONCLUSIONS

There is, contrary to preliminary studies, a broad overlap in RBC 6TGN levels as well as for haematological parameters in patients in remission or not and responders or not to AZA/6-MP therapy. This suggests, beside a variability in the metabolism of these drugs, the existence of complex mechanisms of action. Nevertheless, beside the use of RBC 6TGN determination to confirm compliance to therapy, this dosage could be useful in non-responding patients, allowing, in absence of leukopenia, to increase the dose of AZA/6-MP safely.

Adult-to-adult living related liver transplantation: initial experience

The number of adult patients on the liver transplantation waiting lists is growing steadily. Adult living related liver transplantation (LRLT) represents the ultimate means to expand the donor pool. The success of this model of "small for size" grafting relies on strict donor and recipient selection. The choice of the graft (2 left and 4 right hepatectomies) was made on the minimal ratio between estimated graft and recipient body weights (0.8-1%), necessary to meet the recipient's metabolic demands. Our experience with six adults is reported. Donor morbidity was minimal (one wound infection); there was no mortality. Four (66%) recipients are doing well, two died of infectious complications. All recipients had a complicated post-transplant course. Due to its complexity, both in donor and recipient, LRLT should only be developed very carefully in experienced liver transplant centers.

Non-invasive quantification of liver perfusion with dynamic computed tomography and a dual-input one-compartmental model

Various liver diseases lead to significant alterations of the hepatic microcirculation. Therefore, quantification of hepatic perfusion has the potential to improve the assessment and management of liver diseases. Most methods used to quantify liver perfusion are invasive or controversial. This paper describes and validates a non-invasive method for the quantification of liver perfusion using computed tomography (CT). Dynamic single-section CT of the liver was performed after intravenous bolus administration of a low-molecular-mass iodinated contrast agent. Hepatic, aortic and portal-venous time-density curves were fitted with a dual-input one-compartmental model to calculate liver perfusion. Validation studies consisted of simultaneous measurements of hepatic perfusion with CT and with radiolabelled microspheres in rabbits at rest and after adenosine infusion. The feasibility and reproducibility of the CT method in humans was assessed by three observers in 10 patients without liver disease. In rabbits, significant correlations were observed between perfusion measurements obtained with CT and with microspheres (r=0.92 for total liver perfusion, r=0.81 for arterial perfusion and r=0.85 for portal perfusion). In patients, total liver plasma perfusion measured with CT was 112+/-28 ml.min(-1).100 ml(-1), arterial plasma perfusion was 18+/-12 ml.min(-1).100 ml(-1) and portal plasma perfusion was 93+/-31 ml.min(-1).100 ml(-1). The measurements obtained by the three observers were not significantly different from each other (P>0.1). Our results indicate that dynamic CT combined with a dual-input one-compartmental model provides a valid and reliable method for the non-invasive quantification of perfusion in the normal liver.

Early down-regulation of cytochrome P450 3A and 2E1 in the regenerating rat liver is not related to the loss of liver mass or the process of cellular proliferation

AIMS/BACKGROUND

Conflicting data have been reported concerning the modification of cytochrome P450 expression in the regenerating liver. Ligation of branches of the portal vein (PBL) perfusing 70% of the liver parenchyma, which produces regeneration and atrophy within the same liver, constitutes an ideal model to study the relative specificity of the early events in the regenerating liver and their relationship to the loss of liver mass.

METHODS

In this PBL model and in sham models, we studied the expression and the metabolic activities of two major cytochromes, CYP3A and CYP2E1, and the expression of inducible nitric oxide synthase protein (iNOS). They were simultaneously measured in the atrophying and regenerating liver lobes following PBL using Western Blot and HPLC methods.

RESULTS

The metabolic activities of both cytochromes were transiently and simultaneously down-regulated in the regenerating and atrophying lobes during the first 2-5 h after PBL. No significant modification was observed at the protein level. In contrast, iNOS protein was significantly induced in both lobes. Similar results were observed after sham operation.

CONCLUSIONS

The reduction of these CYP activities in both lobes after PBL and in sham livers suggests that other mechanisms than the regenerating process itself or the reduction of the liver mass might account for such down-regulation during the early phase of liver regeneration. The activation of nitric oxide (NO) and/or pro-inflammatory cytokine production provides clues to pathways liable to affect the CYP activities in the regenerating liver.

The compensatory hyperplasia (liver regeneration) following ligation of a portal branch is initiated before the atrophy of the deprived lobes

BACKGROUND/AIMS

In rats, partial ligation of portal branches produces atrophy of the deprived lobes and hypertrophy of the intact lobes. The hepatocyte proliferation observed in the nondeprived lobes is viewed as a compensatory hyperplasia, implying that the atrophy somewhat precedes the initiation of the proliferative response. As this has not been demonstrated, the time course and magnitude of those two sequences of events were investigated and compared with the well-defined response to a partial hepatectomy.

METHODS

The portal branch feeding the anterior liver lobes was ligated in male Wistar rats. One-third and two-thirds partial hepatectomies were also performed. Liver weight, the aminopyrine demethylation rate, an index of the liver mass, the DNA content and various indices of cell proliferation were measured.

RESULTS

Resection of the anterior lobes (PH) or ligation of their portal blood supply (PBL) induced a marked DNA synthesis in the posterior lobes (3H-thymidine incorporation) reaching its maximum 24 h after both interventions. This response can even be accelerated by performing a sham operation 6 h before the PBL. The process leading to DNA synthesis thus seems to start as early after PBL as after a PH, although the weight of the liver or the aminopyrine demethylation rate was nearly unchanged 2 h following PBL. The initiation of the proliferative response clearly precedes and is thus independent of the reduction of the liver mass. On the other hand, the progressive reduction of the liver mass seems to determine the magnitude of the proliferative response, which is, for instance, greatly increased following the excision of the deprived lobes, as late as 10 h after ligation of their portal branches. In comparison with the results obtained after a 113 PH, the peak of DNA synthesis at the 24th hour is greater than predicted by the liver weight loss, but this parameter could underestimate the reduction of the functional liver mass.

CONCLUSION

The proliferative response following a PBL can be divided into an early phase occurring independently of the reduction of the liver mass and a late phase controlled by this reduction. The paradox of the proliferative response which seems to start before the atrophy to be compensated is resolved by this hypothesis.

Relationship between red cell mean corpuscular volume and 6-thioguanine nucleotides in patients treated with azathioprine

Azathioprine (AZA) is characterized by high interindividual differences in bioavailability and metabolization. The aim of the present study was to analyze, in patients treated with AZA for various immune system disorders, whether the variation in red blood cell mean corpuscular volume (deltaMCV) could be used as an indirect estimation of the level of the active immune modifier metabolite 6-thioguanine nucleotides (6-TGN). In 43 consecutive patients treated with a stable dose of AZA for at least 6 months who were not initially anemic, the erythrocyte 6-TGN levels with routine hematologic parameters were determined two to four times at 1-month intervals. In most patients MCV significantly increased after 3 months of therapy and stabilized after 6 months. The correlation between the daily dose of AZA and the 6-TGN level was mild (r = 0.51; P<.001). A weak correlation was also found between the dose of AZA and the deltaMCV after at least 6 months of therapy (r = 0.36; P<.05). The correlation between deltaMCV and 6-TGN level, however, was much better (r = 0.74; P<.001). The lack of a significant increase in MCV after 3 to 4 months of AZA therapy reflects low 6-TGN levels, sometimes a result of undertreatment. A determination of the 6-TGN level during the first months after AZA therapy is begun will allow more accurate adaptation of the effective dose. We observed that deltaMCV could be used as an indicator of 6-TGN levels after 6 months of AZA treatment. An increase in MCV of at least 6 fL is expected to reflect a 6-TGN level of about 175 pmol/8x10(8) red blood cells (probably being within a therapeutic value).

Gadolinium-enhanced arterial-phase MR imaging of hypervascular liver tumors: comparison between tailored and fixed scanning delays in the same patients

The purpose of this study was to compare in the same patients tailored and fixed scanning delays during gadolinium-enhanced arterial-phase magnetic resonance imaging of hypervascular liver tumors. Tailored scanning delays were obtained with automated region of interest threshold triggering. A delay of 23 seconds between the start of contrast material injection and imaging was used for fixed delay examinations. Quantitative and qualitative evaluation was performed in 21 patients with normal cardiac function referred for MR assessment of hypervascular liver tumors. In the tailored examinations, the median time delay between the start of contrast material injection and the start of magnetic resonance imaging was 21 seconds (range, 18-34 seconds). The median tumor-to-liver contrast during tailored examinations was 19.1 versus 14.7 during fixed delay examinations. This difference, however, was not significant. Similarly, the enhancement in the aorta, the portal vein, the liver, and the tumor did not differ significantly between examinations performed with tailored and fixed delays. It is concluded that in our group of patients with hypervascular liver tumors and normal cardiac function, no significant improvement in tumor-to-liver contrast and enhancement during the arterial phase was found when gadolinium-enhanced magnetic resonance imaging was performed with a tailored scanning delay rather than with a fixed delay.

Disposable versus reusable biopsy forceps: a prospective cost evaluation

BACKGROUND

There is growing advocacy for the use of disposable medical accessories to reduce the risks of infection transmission. Their purchase costs can, however, be considered as prohibitive in an endoscopy unit operating under a cost-containment program. We therefore compared the costs of reusable and disposable biopsy forceps.

METHODS

From October 1995 to September 1997, biopsies were obtained in 7740 sessions. The evaluation of costs included purchase prices, repairs, cleaning (chemicals, equipment, technician time) and autoclaving costs in a centralized sterilization unit. For comparison, the lowest purchase price for disposable biopsy forceps was $26.90 in 1997.

RESULTS

A mean of 12 new reusable forceps were purchased every year for a total purchase price of $5460. A total of 315 biopsy sessions were performed per forceps (mean time life of 3 years per forceps, including 3 repairs). Yearly repair cost was $3308, equipment $1002, chemicals $3250, central sterilization $8333, and technician salary $4373. Total cost was $25,726 and cost per biopsy session was $6.65.

CONCLUSIONS

Total purchase and reprocessing costs for reusable biopsy forceps were 25% of those of disposable devices. The use of disposable biopsy forceps would have led to a yearly extra cost of $78,377 in the operation of our endoscopy unit.

Dramatic response after an intravenous loading dose of azathioprine in one case of severe and refractory ankylosing spondylitis

We describe a 37-yr-old Caucasian male suffering from ankylosing spondylitis (AS) with long-standing severe inflammatory lumbar pain and hip arthritis who was refractory to non-steroidal anti-inflammatory drugs, sulphasalazine and methotrexate up to 25 mg/week. In this patient, administration of an i.v. loading dose of azathioprine (AZA; 40 mg/kg for 36 h followed by 2 mg/kg oral AZA therapy) induced a dramatic response in his clinical condition. Indeed, objective and subjective clinical variables improved within 1 week and were corroborated by a decline in the levels of the inflammatory parameters; anaemia was reported at month 3 but was rapidly reversible. If confirmed, an i.v. loading dose of AZA could represent a valuable alternative in severe and refractory AS, but toxicity of this regimen should be carefully analysed.

Differential activities of CYP1A isozymes in hepatic and intestinal microsomes of control and 3-methylcholanthrene-induced rats

Differences in expression of CYP1A isoforms (CYP1A1 and CYP1A2) in liver and small intestine of male Wistar rats and their inducibility by 3-methylcholanthrene as well as the effect of different CYP1A1/1A2 expression on caffeine metabolism were investigated. In rat liver, CYP1A2 is the predominant isoform and CYP1A1 protein expression in liver is significantly increased after treatment by 3-methylcholanthrene. In contrast, only CYP1A1 was detected in control and 3-methylcholanthrene induced small intestine microsomes. Treatment with 3-methylcholanthrene (40 mg/kg intraperitoneally daily during 1, 2, 3 or 4 days) demonstrated that liver CYP1A1 is more sensitive for the induction effects than CYP1A2 and also that significant induction of CYP1A1 in rat small intestine only occurred after 3 to 4 days pretreatment. Caffeine metabolism and inhibition studies by furafylline, CYP1A1 antiserum and ketoconazole revealed that the differences in the expression of CYP1A1 and CYP1A2 in the two tissues led to significant changes in the contribution of the various isoenzymes involved in the biotransformation of caffeine. Whereas in liver paraxanthine formation was almost exclusively catalyzed by CYP1A2, in rat proximal intestine it was formed by CYP1A1. In addition, other CYP enzymes (most probably CYP3A) play a significant role in theobromine and theophylline formation from caffeine in rat intestine. Overall, this study shows different expression and inducibility of CYP1A1/1A2 by 3-methylcholanthrene in rat liver and small intestine. Furthermore in rat intestine cytochrome P450 isozymes such as CYP1A1 and CYP3A replace CYP1A2 in the caffeine metabolism.

Focal nodular hyperplasia: natural course observed with CT and MRI

PURPOSE

The purpose of this work was to assess the natural course of biopsy-proven focal nodular hyperplasia (FNH).

METHOD

Eighteen biopsy-proven FNHs in 14 patients (12 women and 2 men) who were followed for at least 6 months with CT and/or MRI were included in the study. The volume of the lesions was calculated twice by two observers using the summation of areas method. Intra- and interobserver variability was assessed by intraclass correlation coefficients. Longitudinal data analysis was performed with generalized estimating equations.

RESULTS

The volume of FNH was stable in 6 cases, decreased in 10 cases, and increased in 2 cases. Intra- and interobserver variability in size measurements was 5-10%. Intraclass correlation coefficients were >0.992. Longitudinal data analysis showed that there was a general trend of lesion regression.

CONCLUSION

Long-term follow-up and objective measurements performed in patients with biopsy-proven lesions show that the natural course of FNH is variable. In particular, lesion regression is not rare.

HLA association of amoxicillin-clavulanate--induced hepatitis

BACKGROUND & AIMS

Drug-induced immunoallergic hepatitis typically affects a minority of patients exposed to a particular drug. Its rarity is believed to be due to metabolic or immunologic idiosyncrasy. The presence of an immunologic idiosyncrasy might imply an HLA association. Previous studies reporting an HLA association of drug-induced hepatitis included only small numbers of patients and used serological HLA typing.

METHODS

We studied 35 patients with biopsy-documented amoxicillin-clavulanate-induced hepatitis. HLA-A and -B were typed using alloantisera and compared with those of 300 controls (volunteer bone marrow donors). HLA-DRB and -DWB were typed by polymerase chain reaction-line probe assay, with 60 volunteer bone marrow donors serving as controls.

RESULTS

The study group was characterized by a higher frequency of DRB1*1501-DRB5*0101-DQB1*0602 haplotype (57.1% vs. 11.7% in controls, P < 0.000005; after correction for the large number of comparisons, P < 0.0002). Patients with DRB1*1501-DRB5*0101-DQB1*0602 haplotype were more likely than patients without it to have a cholestatic (70% vs. 60%) or mixed (30% vs. 13%) than a hepatocellular pattern of hepatitis (0% vs. 27%) (P < 0.05).

CONCLUSIONS

Amoxicillin-clavulanate-induced hepatitis is associated with the DRB1*1501-DRB5*0101-DQB1*0602 haplotype. The data support the view that an immunologic idiosyncrasy, mediated through HLA class II antigens, plays a role in the pathogenesis of drug-induced immunoallergic hepatitis. HLA association has a limited impact on the expression of hepatitis.

Dietary restriction of energy and sugar results in a reduction in human cytochrome P450 2E1 activity

Dietary habits are often considered as a pathogenic factor for fatty liver. The impact of dietary intake and steatosis on drug metabolism remains poorly investigated. Our aim was to assess the effect of dietary intake on in vivo cytochrome P450 (CYP) activities in eleven patients with abnormal liver function tests potentially due to fatty liver and associated with a high-sugar diet. Liver function tests, liver volume, aminopyrine breath test (ABT) and chlorzoxazone (CZ) pharmacokinetics (area under the curve, AUC) which are known to reflect CYP2E1 activity were evaluated before and after 2 months restriction of dietary sugar intake. Features at inclusion were an increased BMI (30.3 (SD 3.2) kg/m2), high hepatic volume (1.96 (SD 0.48) litres), hyperechogenic liver parenchyma, elevated liver enzyme activities (alanine aminotransferase (EC 2.6.1.2) 58.6 (SD 17.4) IU/1 with alanine aminotransferase: aspartate aminotransferase (EC 2.6.1.1) ratio > 1), together with a normal ABT value (0.68 (SD 0.21)% specific activity of administered dose of [14C]aminopyrine in breath after 1 h) and a high CYP2E1 activity (CZ AUC 20.3 (SD 7.1) micrograms/ml per h). A dietary sugar restriction was prescribed. On the basis of repeated interviews by the same dietitian, unaware of any clinical and biochemical data, six patients remained complaint to the diet and exhibited reductions in BMI (P < 0.001), serum alanine aminotransferase (P = 0.008), liver volume (P = 0.002) and CYP2E1 activity (P = 0.007), a significant increase in ABT (P < 0.001) together with the disappearance of liver hyperechogenicity at ultrasound. In contrast, the five non-compliant patients did not show any significant change in any of these variables. In conclusion, CYP2E1 activity is induced in patients with perturbations of liver function tests potentially due to fatty liver. In these patients, effective dietary sugar restriction is associated with a reduction in liver volume, a reduction in CYP2E1 activity and an increased aminopyrine metabolism rate.

MR imaging of hypervascular liver tumors: timing optimization during the arterial phase

To analyze the optimal timing strategy for the detection of hypervascular liver tumors during the arterial phase of magnetic resonance (MR) imaging, a test examination after injection of 2 mL of gadopentetate dimeglumine was performed in 47 patients. The time course of the tumor-to-liver contrast-to-noise ratio (CNR) for all studies together was determined relative to the start of injection, the time of peak aortic enhancement, and the time of peak enhancement in the tumor. All studies were grouped together and the highest CNR was transiently observed at the time of peak tumor enhancement. This CNR was significantly higher than those observed at fixed delays after peak aortic enhancement. However, the CNRs at peak tumor enhancement+/-1.5 seconds did not differ significantly from those obtained after peak aortic enhancement. Finally, the CNRs obtained at fixed delays after the start of injection remained significantly lower. In hypervascular liver tumors, a higher CNR can be obtained during the arterial phase when the MR imaging delay is determined relative to the time of peak enhancement in the tumor or the aorta rather than being fixed after the start of contrast material injection. Timing based on the enhancement profile in the tumor rather than in the aorta should be performed only if rapid MR imaging is available with a time resolution of about 1.5 seconds to image the whole liver.