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Biomedical subjects

Michel Mourad

Publications and source records attributed to Michel Mourad.

8 recordsLinked to original sources
PubMed2006

The place of liver transplantation in Caroli's disease and syndrome.

Caroli's disease (CD) or syndrome (CS) are rare inherited disorders which may cause severe, life-threatening, cholangitis or which may lead to hepatobiliary degeneration. The typical cystic biliary anomalies are often associated to congenital hepatic fibrosis (CHF) and, less frequently, to cystic renal disease especially autosomic recessive polycystic kidney disease (ARPKD). The place of liver transplantation (LT) in the treatment of CD or CS is evaluated based on our own experience of three successfully transplanted patients, the literature review of 19 patients and the European experience with 110 patients collected in the European Liver Transplant Registry. LT should be proposed as a definitive therapeutic option once severe cholangitis or (suspicion of) malignant transformation is present. The frequently used radiological, endoscopical or surgical biliary drainage procedures carry a high morbidity and mortality rate. In case of concomitant symptomatic CHF and renal failure, combined or sequential hepatorenal transplantation should be carried out, dependent on the evolution of the hepatic and renal disease. In case of associated ARPKD, renal transplantation is often indicated early on because of the more rapid progression of the renal component of the disease.

Adolescent↗
PubMed2006

The influence of genetic polymorphisms of cytochrome P450 3A5 and ABCB1 on starting dose- and weight-standardized tacrolimus trough concentrations after kidney transplantation in relation to renal function.

BACKGROUND: Cytochrome P450 3A5 (CYP3A5) and ABCB1 polymorphisms have been shown to influence tacrolimus (Tc) blood concentrations in the stable phase after organ transplantation. We hypothesized that Tc pharmacokinetics may be affected by genetic mutations subsequent to starting doses. METHODS: We retrospectively analyzed data from a cohort of 59 kidney transplant recipients, in whom CYP3A5 (intron 3) and ABCB1 (exons 12, 21 and 26) genotypes were correlated to dose- and weight-standardized Tc trough concentrations obtained after initial Tc doses. Renal function, expressed as glomerular filtration rate (GFR) (MDRD equation), on days 7 and 14 after transplantation was evaluated and its relationship with Tc concentrations was analyzed. RESULTS: Dose- and weight-standardized Tc trough concentrations were lower in patients carrying the CYP3A5 *1 allele (p<0.01). There was no statistically significant association with ABCB1 polymorphisms. In a multivariate analysis, both the presence of at least one CYP3A5 *1 allele (p=0.006) and age at the time of transplantation (p=0.010) were significant independent variables affecting Tc trough blood concentrations standardized to the first dosages (model r2=0.23). GFR was not affected by Tc concentrations. CONCLUSIONS: Prospective trials are needed to prove that a genetic approach to Tc pharmacokinetics and its related side effects during the early period after grafting may improve patient outcome.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2005

Sirolimus and tacrolimus trough concentrations and dose requirements after kidney transplantation in relation to CYP3A5 and MDR1 polymorphisms and steroids.

BACKGROUND: CYP3A5 and MDR1 polymorphisms have been shown to influence tacrolimus blood concentrations and dose requirements. The aim is to determine whether these polymorphisms also affect sirolimus trough concentrations and dose requirements after kidney transplantation. METHODS: Eighty-five renal transplant recipients receiving sirolimus were included. Twenty-four were treated with a combined sirolimus-tacrolimus regimen. Eighty-one patients received steroids. Sirolimus and tacrolimus were adjusted to a target therapeutic window. CYP3A5 (intron 3) and MDR1 (exons 12, 21, 26) genotypes were correlated to the adjusted trough concentrations and dose requirements for both sirolimus and tacrolimus. RESULTS: There were no significant correlation between adjusted sirolimus trough concentrations or dose requirements and genetic polymorphisms. In a multiple regression model, adjusted-prednisone dose was involved with a positive or negative effect when considering sirolimus dose requirements or adjusted concentrations, respectively. In the subgroup of patients treated by tacrolimus and sirolimus, adjusted tacrolimus doses were higher in patients carrying at least one CYP3A5 *1 allele (median 0.083 vs. 0.035 mg/kg for CYP3A5*3/*3 patients, P<0.05). Adjusted-prednisolone dose and CYP3A5 polymorphism explained up to 61% of the variability in tacrolimus dose requirements. CONCLUSIONS: Unlike tacrolimus, sirolimus adjusted trough concentrations and dose requirements seem not affected by CYP3A5 and MDR1 polymorphisms. Adjusted-prednisone dose has a significant impact on tacrolimus and sirolimus dose requirements.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Efficacy and cardiovascular safety of daclizumab, mycophenolate mofetil, tacrolimus, and early steroid withdrawal in renal transplant recipients: a multicenter, prospective, pilot trial.

This single-arm, open-label, pilot study was designed to assess the efficacy and cardiovascular safety profile of daclizumab, a humanized monoclonal interleukin (IL)-2Ralpha antibody, in combination with mycophenolate mofetil (MMF), tacrolimus, and early corticosteroid withdrawal in renal transplant recipients. Seventy-nine renal allograft recipients were treated with daclizumab (1 mg/kg; five doses starting on the day before transplant and then every two weeks), MMF (1 g b.i.d.), tacrolimus (0.2 mg/kg/d), and low-dose prednisolone, which was withdrawn at day 150 after transplant. The rate of acute rejection was determined at 12 months. Lipid profile, oral glucose tolerance, and adverse events were monitored. Of the 76 patients eligible for analysis, eight (10.5%) developed biopsy-proven acute rejection (BPAR). Ten (13.2%) experienced clinical and/or BPAR. Corticosteroids were withdrawn completely in 91% of patients at 12 months. Graft and patient survival were 97.5% and 98.7% respectively. Mean total cholesterol and triglycerides were significantly lower at 12 months post-transplant than at baseline (201 +/- 47.5 vs. 190.8 +/- 43.6 mg/dL, p = 0.005 and 196.2 +/- 133.2 vs. 144.5 +/- 76.8 mg/dL, p < 0.001, respectively). Mean hemoglobin A1c levels did not differ between baseline (5.54%) and 12 months (5.48%). New-onset post-transplant diabetes mellitus occurred in 6.6% of the non-diabetic transplanted patients. The proportion of patients with abnormal oral glucose tolerance test (OGTT) was 47% at 3 months and 39% at 12 months (p = NS). Daclizumab induction in combination with MMF, tacrolimus, and low-dose (followed by withdrawal) prednisolone appears to be effective and safe in patients receiving renal allografts. The regimen appears to be associated with a favorable cardiovascular profile.

Antibodies, Monoclonal↗
PubMed2004

The effect of CYP3A5 and MDR1 (ABCB1) polymorphisms on cyclosporine and tacrolimus dose requirements and trough blood levels in stable renal transplant patients.

Cyclosporine and tacrolimus are immunosuppressive drugs largely used in renal transplantation. They are characterized by a wide inter-individual variability in their pharmacokinetics with a potential impact on their therapeutic efficacy or induced toxicity. CYP3A5 and P-glycoprotein appear as important determinants of the metabolism of these drugs. The objective of this study was to investigate the effect of CYP3A5 and MDR1 (ABCB1) polymorphisms on cyclosporine and tacrolimus dose requirements and trough blood concentrations in stable transplant patients. Stable renal transplant recipients receiving cyclosporine (n = 50) or tacrolimus (n = 50) were genotyped for CYP3A5*3 and *6, and MDR1 C1236T, G2677T/A and C3435T. Dose-adjusted trough blood levels (ng/ml per mg/kg body weight) as well as doses (mg/kg body weight) required to achieve target blood concentrations were compared among patients according to allelic status for CYP3A5 and MDR1. Dose-adjusted trough concentrations were three-fold and 1.6-fold higher in CYP3A5*3/*3 patients than in CYP3A5*1/*3 patients for tacrolimus and cyclosporine, respectively. In the case of tacrolimus, the difference was even more striking when considering CYP3A5*1/*1 patients showing dose-adjusted trough concentrations 5.8-fold lower than CYP3A5*3/*3 patients. For both drugs, no association was found between trough blood concentrations or dose requirement and MDR1 genotype. Multiple regression analyses showed that CYP3A5*1/*3 polymorphism explained up to 45% of the variability in dose requirement in relation to tacrolimus use. Given the importance of rapidly achieving target blood concentrations after transplantation, further prospective studies should consider the immediate post-graft period and assess the influence of this specific polymorphism. Beside non-genetic factors (e.g. steroids dosing, drugs interactions), CYP3A5 pharmacogenetic testing performed just before transplantation could contribute to a better individualization of immunosuppressive therapy.

Cohort Studies↗
PubMed2002

Minimally invasive video-assisted thyroidectomy: multiinstitutional experience.

Minimally invasive video-assisted thyroidectomy (MIVAT) was described in 1998. In this study we collected the experience of four third-level referral centers that adopted this technique. A total of 336 patients (279 females, 57 males) were selected for MIVAT. Selection criteria were thyroid volume <15 ml, nodules not exceeding 3.5 cm of diameter, and an absence of thyroiditis, previous neck surgery, or previous irradiation. The procedure, totally gasless, is carried out through a 15 mm central incision above the sternal notch. Dissection is performed under endoscopic vision using conventional and endoscopic instruments. The mean operating time was 69.4 +/- 30.6 minutes for lobectomy (range 20-150 minutes) and 87.4 +/- 43.5 minutes for total thyroidectomy (range 30-220 minutes). The mean postoperative stay was 1.9 +/- 0.8 days. Postoperative complications were 7 transient and 1 definitive recurrent nerve palsies and 11 cases of hypoparathyroidism (9 transient, 2 definitive). Conversion to open surgery was necessary in 15 patients (4.5%). This study confirms in a large number of cases the safety and feasibility of MIVAT, even in different surgical settings where similar results were achieved. The complication rate was not different from that of standard thyroidectomy. Although the operating time appears longer than with conventional procedures, the learning curve demonstrates a sharp decrease with increasing experience and the introduction of new technologies. The number of patients eligible for this approach remains low, thereby limiting its use, but it should be considered a valid option in selected surgical centers, offering some advantages to patients in terms of cosmetic results and postoperative distress.

Adolescent↗
PubMed2002

Therapeutic monitoring of mycophenolate mofetil in organ transplant recipients: is it necessary?

Adequate immunosuppression minimising the risk of organ rejection with acceptable tolerability of the used drugs is a crucial step in organ transplantation. The primary goal is to maintain a consistent time-dependent target concentration by tailoring individual dosage leading to the best efficacy and tolerability combination. The use of therapeutic drug monitoring (TDM) to optimise immunosuppressive therapy is routinely employed for maintenance drugs such as cyclosporin and tacrolimus. The question whether therapeutic monitoring of mycophenolic acid (MPA) in organ transplant recipients treated with mycophenolate mofetil is necessary is not definitely answered. The correlation of mycophenolic acid pharmacokinetic parameters with efficacy and toxicity makes the therapeutic monitoring of this drug promising. However, further studies are mandatory to draw the best guidelines in order to achieve higher levels of evidence that MPA-TDM may improve patient outcome.

Drug Monitoring↗