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Biomedical subjects

K Paradis

Publications and source records attributed to K Paradis.

At least 19 recordsLinked to original sources
PubMed2000

NOF-11: a one-year pediatric randomized double-blind comparison of neoral versus sandimmune in orthotopic liver transplantation.

BACKGROUND: Although cyclosporine (CsA) has been a mainstay in liver transplantation immunosuppression the original formulation [Sandimmune (SIM)] has variable absorption, particularly in children. Neoral is a new formulation of CsA that may have improved biovailability that would be advantageous in children. This study was undertaken to assess the pharmacokinetics (PK) and effects on outcome of Neoral versus Sandimmune (SIM) in primary pediatric liver transplant recipients. METHODS: Thirty-two patients were randomized to receive Neoral (17 patients) or SIM (15 patients) in the early posttransplant period (days 1-7) in a double-blind fashion. Intravenous CsA was instituted immediately posttransplant followed by Neoral or SIM as soon as the patient was tolerating oral fluids (days 1-7). PK were compared after the first dose (1-7 days), 3 weeks, and 6 and 12 months posttransplant. In addition, side effects, effect of age and food on absorption, and rejection episodes were assessed by intent to treat analysis. Notable characteristics of this study include the use of a central laboratory for all sample analyses and the assessment of renal function using radioisotopic evaluation of glomerular filtration rates. RESULTS: At baseline the two groups were comparable. Neoral resulted in higher peak levels of CsA and total drug exposure with comparable time to peak drug levels at days 1-7 and week 3. This trend was maintained at 6 and 12 months. Time on i.v. CsA was reduced in the Neoral group (8.4 vs. 11.1 days) and the weight adjusted daily dose of SIM required to achieve target trough levels was about 2-fold more than Neoral from day 22 onward. In addition, biopsy proven and treated and steroid-resistant rejection episodes were fewer in the Neoral group (6 vs. 12; P=0.01 and 1 vs. 8: P=0.004, respectively). Side effects were comparable in both treatment groups. CONCLUSIONS: Neoral was well tolerated and had greater biovailability than SIM without any increase in the incidence of side effects. In addition fewer episodes of rejection were observed with Neoral versus SIM. We conclude that Neoral is the CsA formulation of choice for use in pediatric liver transplant recipients.

Child↗
PubMed1999

Search for cross-species transmission of porcine endogenous retrovirus in patients treated with living pig tissue. The XEN 111 Study Group.

Pig organs may offer a solution to the shortage of human donor organs for transplantation, but concerns remain about possible cross-species transmission of porcine endogenous retrovirus (PERV). Samples were collected from 160 patients who had been treated with various living pig tissues up to 12 years earlier. Reverse transcription-polymerase chain reaction (RT-PCR) and protein immunoblot analyses were performed on serum from all 160 patients. No viremia was detected in any patient. Peripheral blood mononuclear cells from 159 of the patients were analyzed by PCR using PERV-specific primers. No PERV infection was detected in any of the patients from whom sufficient DNA was extracted to allow complete PCR analysis (97 percent of the patients). Persistent microchimerism (presence of donor cells in the recipient) was observed in 23 patients for up to 8.5 years.

Adolescent↗
PubMed1999

The kidney in children with tyrosinemia: sonographic, CT and biochemical findings.

BACKGROUND: Tyrosinemia relates to a deficiency of fumarylacetoacetate hydrolase and presents early in life with central nervous system and liver abnormalities. Renal function is often impaired. Little is known about the architecture and function of the kidneys. OBJECTIVE: Imaging changes on US and CT are compared to the function of the kidneys in children with tyrosinemia, and followed after liver transplantation. MATERIALS AND METHODS: Renal sonography, CT and renal function tests in 32 children were reviewed. Renal length, volume, echogenicity and nephrocalcinosis were evaluated. Renal function was assessed by glomerular filtration rate, and the presence of aminoaciduria, acidosis and calciuria. Seventeen children had open renal biopsy during time of liver transplantation. Histology was reviewed. Statistical analyses relating renal structure to function were performed, and repeated after transplantation. RESULTS: The kidneys were enlarged (47 %), hyperechogenic (47 %) and showed nephrocalcinosis (16 %). There was delayed excretion of contrast medium at CT in 64 %. Aminoaciduria was present in 82 % of children, hypercalciuria in 67 %, tubular acidosis in 59 %, and low GFR in 48 %. Delayed excretion of contrast was associated with low GFR (P < 0.05). Renal biopsies showed dilated tubules (81 %), interstitial fibrosis (56 %), glomerulosclerosis (56 %) and tubular atrophy (56 %). During a mean observation period of 3 years following liver transplantation, GFR improved in 50 %, tubular acidosis in 50 % and hypercalciuria in 70 %. No change was noted in renal size or sonographic architecture. CONCLUSION: Renal architecture and function are abnormal in the majority of children with tyrosinemia. Liver transplantation improves renal function in about 50 % of patients, but abnormal renal size and architecture persist.

Amino Acid Metabolism, Inborn Errors↗
PubMed1999

Entry-into-human study with the novel immunosuppressant SDZ RAD in stable renal transplant recipients.

AIMS: To evaluate the tolerability of single oral SDZ RAD doses in stable renal transplant recipients and the pharmacokinetics of ascending SDZ RAD doses when coadministered with steady-state cyclosporin A microemulsion (Neoral). METHODS: This randomized, double-blind, placebo-controlled, sequential study involved 54 patients in six treatment groups; a different SDZ RAD dose (0.25, 0. 75, 2.5, 7.5, 15, 25 mg) was assessed in each group. Patients received a single oral dose of SDZ RAD (n=6) or placebo (n=3) with their usual Neoral dose. SDZ RAD and cyclosporin A pharmacokinetic parameters were determined. RESULTS: All SDZ RAD doses were well tolerated, with no discontinuations due to adverse events, serious adverse events, or deaths. Similar proportions of patients receiving SDZ RAD and placebo had at least one adverse event (44% and 50%, respectively). Mean changes in laboratory variables (baseline to endpoint) showed no clinically meaningful differences between SDZ RAD and placebo groups. SDZ RAD was absorbed rapidly and showed dose-proportional pharmacokinetics (dose: 2.5-25 mg), based on systemic exposure. Multiple postabsorptive phases in the pharmacokinetic profile indicate tissue distribution. The elimination half-life ranged from 24 to 35 h across the five highest dose groups. Pharmacokinetics were similar in men and women. Co-administration of escalating single oral SDZ RAD doses did not affect steady-state cyclosporin A pharmacokinetics. CONCLUSIONS: SDZ RAD was well tolerated; safety profiles of SDZ RAD and placebo were similar. SDZ RAD pharmacokinetics were dose-proportional across the range 2.5-25 mg in conjunction with cyclosporin A-based therapy, according to systemic exposure. Cyclosporin A pharmacokinetics were not affected by coadministration of single oral doses of 0.25-25 mg SDZ RAD.

Adolescent↗
PubMed1999

Bile duct cells: a novel in vitro model for the study of lipid metabolism and bile acid production.

Immortalized bile duct cells (BDC), derived from transgenic mice harboring the SV40 thermosensitive immortalizing mutant gene ts458, were utilized to investigate the role of the biliary epithelium in lipid and sterol metabolism. This cell model closely resembles the in vivo situation because it expresses the specific phenotypic marker cytokeratin 19 (CK-19), exhibits the formation of bile duct-like structures, and displays well-formed microvilli projected from the apical side to central lumen. The BDC were found to incorporate [14C]oleic acid (in nmol/mg protein) into triglycerides (121 +/- 6), phospholipids (PL; 59 +/- 3), and cholesteryl ester (16 +/- 1). The medium lipid content represented 5.90 +/- 0.16% (P < 0. 005) of the total intracellular production, indicating a limited lipid export capacity. Analysis of PL composition demonstrated the synthesis of all classes of polar lipids, with phosphatidylcholine and phosphatidylethanolamine accounting for 60 +/- 1 and 24 +/- 1%, respectively, of the total. Differences in PL distribution were apparent between cells and media. Substantial cholesterol synthesis was observed in BDC, as determined by the incorporation of [14C]acetate suggesting the presence of hydroxymethylglutaryl-CoA (HMG-CoA) reductase, the rate-limiting enzyme in the cholesterol biosynthetic pathway. With the use of [14C]acetate and [14C]cholesterol as precursors, both tauro- and glycoconjugates of bile acids were synthesized, indicating the presence of cholesterol 7alpha- and 26R-hydroxylases, the key enzymes involved in bile acid formation. The transport of bile acids was not limited, as shown by their marked accumulation in the medium (>6-fold of cell content). HMG-CoA reductase (53.0 +/- 6.7), cholesterol 7alpha-hydroxylase (15. 5 +/- 0.5), and acyl-CoA:cholesterol acyltransferase (ACAT; 201.7 +/- 10.2) activities (in pmol. min-1. mg protein-1) were present in the microsomal fractions. Our data show that biliary epithelial cells actively synthesize lipids and may directly contribute bile acids to the biliary fluid in vivo. This BDC line thus represents an efficient experimental tool to evaluate biliary epithelium sterol metabolism and to study biliary physiology.

Acetates↗
PubMed1997

Developmental profile of mitochondrial glycine N-acyltransferase in human liver.

OBJECTIVE: To study the developmental profile of glycine N-acyltransferase (GAT) in the livers of children of various ages and to compare the total and specific GAT activity with that of the adult control subjects. METHODS: We measured the specific and the total mitochondrial activity of GAT in liver samples taken from 13 children 4 hours to 11 years of age. The samples were compared with those of control adults aged 24 to 40 years. Samples, either from liver-transplant donors or from autopsy, from those who died of a disorder not related to the liver, were obtained between 6 and 36 hours after death. RESULTS: At 4 hours after birth, very low specific activity and the total liver mitochondrial activity were observed (0.19 mumol/min per milligram protein and 210 mumol/min), with a steady increase up to age 7 months (2.51 mumol/min per milligram protein and 812 mumol/min). The mean specific and total GAT activity in children (n = 5) aged 18 months to 11 years was 6.38 +/- 0.13 and 1389 +/- 43 and in control adults aged 24 to 40 years (n = 3) was 6.5 +/- 0.3 and 1461 +/- 71 mumol/min per milligram protein and mumol/min, respectively. These specific and total GAT activity values from children aged 18 months to 11 years were not statistically significant (by analysis of variance and Mann-Whitney test) in comparison with the corresponding activity values from the adult control subjects. CONCLUSIONS: Our results indicate that up to age 7 months, children have only 5% to 40% of liver GAT-specific activity, whereas the peak activity is achieved at 18 months and remains constant until age 40 years. The delayed development of GAT in children may thus compromise the detoxification of various drugs and xenobiotics.

Acyltransferases↗
PubMed1997

Ursodeoxycholic acid improves the hepatic metabolism of essential fatty acids and retinol in children with cystic fibrosis.

OBJECTIVE: Several clinical trials of ursodeoxycholic acid (UDCA) have shown improvement of liver-function test results in cystic fibrosis (CF) with liver disease; however, there is no evidence that the long-term course will be affected. In view of the observations that UDCA can change the lipid profile and that patients with CF and liver disease are more likely to have essential fatty acid (EFA) deficiency, we elected to examine changes in the lipid profile and in the status of fat-soluble vitamins in response to UDCA. METHODS: Nineteen children with CF and liver dysfunction were recruited for a double-blind, crossover study of 1 year's duration, followed by treatment of the entire group. UDCA was administered at a dosage of 15 mg/kg per day, which, in the absence of a 50% decrease of alanine transaminase or aspartate transaminase or both within 2 months, was increased to 30 mg/kg per day. RESULTS: At entry, all patients had biochemical evidence of EFA deficiency. The lipid profiles during an average period of 25 months of follow-up showed a significant decrease in triglycerides (p <0.002), cholesterol (p <0.02), and total fatty acids (p <0.006). In addition, UDCA therapy led to an improvement in EFA status, as indicated by an increase (p <0.05) in the n-6 fatty acid concentration and a reduction (p <0.04) in the 20:3n-9/20:4n-6 fatty acid ratio. Although no change in vitamin E levels was observed, retinol metabolism was altered. There was an increase (p <0.02) in the unesterified retinol/retinol binding protein molar ratio in the absence of a difference in retinol binding protein concentration. Furthermore, retinyl esters, which normally account for less than 3% of circulating retinol, decreased (p <0.05) from 13.7% +/- 3.6% to 8.1% +/- 1.7%. CONCLUSIONS: This study confirms that UDCA alters lipoprotein metabolism and shows that it improves the EFA and retinol status of patients with CF and liver disease.

Adolescent↗
PubMed1997

Randomized comparison of ganciclovir plus intravenous immune globulin (IVIG) with IVIG alone for prevention of primary cytomegalovirus disease in children receiving liver transplants.

A randomized placebo-controlled trial was conducted to determine the benefit of ganciclovir (5 mg/[kg x d]) for 30 days in addition to intravenous immune globulin (IVIG) for 16 weeks for prevention of primary cytomegalovirus (CMV) disease in children receiving liver transplants. Patients were monitored for 6 months after transplantation. The two groups of patients (recipients of 29 ganciclovir plus IVIG and 27 recipients of IVIG alone) were similar in terms of age, sex, and underlying disease. The incidence of CMV disease among the ganciclovir plus IVIG recipients and the IVIG alone recipients was 17% and 26%, respectively, and the time to disease in these recipients was 46 days and 32 days, respectively. There was no difference between groups in terms of survival; episodes of rejection, bacteremia, or fungemia; use of immunosuppressive agents; and incidence of leukopenia or thrombocytopenia. These results suggest that a 4-week course of ganciclovir with IVIG is not more effective than IVIG alone for prevention of primary CMV disease. Since short-term prophylaxis with ganciclovir may delay the onset of CMV disease, further studies with a longer course of ganciclovir prophylaxis are warranted.

Adolescent↗
PubMed1996

Epstein-Barr virus transmission from a blood donor to an organ transplant recipient with recovery of the same virus strain from the recipient's blood and oropharynx.

A previous study (Savoie et al, Blood 83:2715, 1994) identified eight transplant patients who acquired Epstein-Barr virus (EBV) infection during the peritransplant period. Three of these patients subsequently developed B-cell lymphoproliferative disease within 4 months of transplantation. Among these, there was a 16-year-old liver transplant patient who was negative for EBV at the time of transplant and who received an EBV-negative organ. After transplant, this patient was transfused with 9 U of packed red blood cells. Eight of the donors were EBV-positive and one was EBV-negative. We succeeded in obtaining spontaneous lymphoblastoid cell lines (LCLs) from the blood of three of these donors, one of whom also yielded a cord-blood line established with his throat-wash EBV. Blood from a fourth donor did not yield an LCL, but his throat washing did have transforming activity when inoculated onto cord-blood leukocytes. We initially could establish spontaneous LCLs only from the recipient's blood. However, a throat-wash sample taken 11 weeks later did show transforming activity. The recipient was shown to have acquired the EBV infection from one of eight EBV-seropositive blood donors. Analysis of fragment length polymorphisms after polymerase chain reaction amplification of the EBV BamHI-K fragment was used to establish strain identity. Western blot analysis for existence of size polymorphisms in three classes of Epstein-Barr nuclear antigens (EBNA-1, EBNA-2, and EBNA-3) confirmed the DNA results. It is noteworthy that the blood donor responsible for transmitting his EBV strain to the recipient had experienced clinical infectious mononucleosis 15 months before donating blood. Our results may, thus, indicate a requirement for leukodepletion of blood destined for immunosuppressed EBV-negative patients. Finally, blood donors with a recent history of infectious mononucleosis should probably be identified so that their blood is not given to EBV-negative transplant patients.

Adolescent↗
PubMed1996

Imaging features of type 1 hereditary tyrosinemia: a review of 30 patients.

Hereditary tyrosinemia type 1, a common genetic disorder in the province of Quebec, is characterized by a deficiency of fumarylacetoacetate hydrolase. In this autosomal recessive disorder of tyrosine metabolism, the accumulation of succinylacetone leads to neurologic crises, acute and chronic liver failure, complex renal tubulopathy, rickets and a hemorrhagic syndrome. Liver trans- plantation has dramatically modified the spontaneous course of this lethal disease. The present paper describes the imaging features of tyrosinemia in 30 patients followed from 1980 to 1995 at Hôpital Sainte-Justine, Montreal, Canada.

Adolescent↗
PubMed1996

Phenotypical and functional characterization of intrahepatic bile duct cells from common duct ligated mice.

Bile duct cells (BDCs), especially intrahepatic cholangiocytes, are primary targets of immune-related injury in such pathologic processes as liver graft rejection, liver graft-versus-host disease, and primary sclerosing cholangitis. Cholestasis and progressive loss of intrahepatic BDCs indicate chronicity in these diseases. The present investigation characterizes the acquisition of immune markers of intrahepatic BDCs isolated from mice after bile duct ligation. Purified BDCs from cholestatic C57BL/6 (H-2b) mice express not only the major histocompatibility complex (MHC) class I and class II antigens but also the costimulatory molecules B7-1 (CD80) and B7-2 (CD86). The expression of the MHC class II molecules on BDCs before and after interferon (IFN)-gamma exposure is also demonstrated by immunohistochemistry on the cultured cells. Cytotoxicity assays indicate the vulnerability of these cells as targets for immunologic injuries. Effector cells generated from B10.BR splenocytes (H-2k) against C57BL/6 splenocytes (H-2b) show comparable killing of BDCs and EL4 cells, the latter being a lymphoma line that was established from the C57BL/6N (H-2b) mouse. An immortalized mouse BDC line (IBDC) is included in this study to validate some of the findings from BDCs isolated from bile duct-ligated mice. We suggest that cholestatic BDCs express surface antigens different from those of normal epithelial cells that result in increased susceptibility to damage by immune mechanisms.

Animals↗
PubMed1996

Leucocyte adhesion deficiency presenting as a chronic ileocolitis.

CD11/CD18 leucocyte glycoprotein deficiency is a rare, congenital adhesion molecule disorder which, in its severe form, is usually fatal. Leucocytes in affected subjects have abnormal migration and adherence, rendering patients susceptible to life threatening infections. The CD11/CD18 integrins, and other adhesion molecules, are considered essential to the normal inflammatory response. It has been postulated that adhesion molecules may be responsible for mediating in part, the inflammatory changes observed in inflammatory bowel diseases and related disorders. This report describes the first case of CD11/CD18 deficiency characterised by a chronic ileocolitis. Bone marrow transplantation completely resolved the gastrointestinal symptoms, supporting a role for neutrophil dysfunction in the pathogenesis of the gut lesions. This case suggests that specific blockade of CD11/CD18 integrins alone may not halt the chronic inflammatory response observed in immune mediated bowel disorders, and that abnormalities of leucocyte function must be included in the differential diagnosis of paediatric Crohn's disease.

Bone Marrow Transplantation↗