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Biomedical subjects

D Samuel

Publications and source records attributed to D Samuel.

At least 163 records · Page 9Linked to original sources
PubMed1992

Effects of riluzole (2-amino-6-trifluoromethoxy benzothiazole) on striatal neurochemical markers in the rat, with special reference to the dopamine, choline, GABA and glutamate synaptosomal high affinity uptake systems.

Riluzole, a new compound with anticonvulsant properties, was found to induce a dose-dependent decrease in the uptake of 3H-dopamine, 3H-GABA and 3H-glutamate into striatal synaptosomes when added to the incubation medium or after in vivo administration, whereas an inhibition of 3H-choline uptake was detected only in the in vitro experiments. Interestingly, riluzole affected 3H-dopamine and 3H-glutamate uptake differentially since 3H-dopamine uptake was found to be more sensitive to the compound. Moreover, riluzole inhibited 3H-dopamine uptake competitively and 3H-glutamate uptake non-competitively, which further suggests that the action of the compound is selective. After in vivo injection, riluzole did not affect the striatal dopamine, DOPAC, serotonin, 5HIAA, glutamate, aspartate or GABA contents. Since this compound was previously reported to induce a decrease in the spontaneous release of glutamate, serotonin, dopamine and possibly acetylcholine, the hypothesis is put forward that riluzole may, at least at high concentrations, have general effects on the striatal nerve terminals affecting both the uptake and release processes. This action may be correlated with the recently identified blocking properties of the compound on the sodium channels, as previously shown for local anaesthetics.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Monokine gene expression in normal human liver: selective involvement of the portal compartment.

Monokines play a major role in the regulation of hepatocyte functions. To document a possible in situ production of these mediators under physiological conditions, expression of IL-1 beta and of IL-6 genes was analyzed by in situ hybridization in four histologically normal human livers. We detected cells containing IL-1 beta mRNA or IL-6 mRNA in all cases. Cells expressing either the IL-1 beta gene or the IL-6 gene were found with equal frequency and were similarly distributed. Although present in all liver compartments, they were selectively enriched in portal areas, in which they were detected both in endothelial positions and in perivascular connective tissues. Few positive cells were observed in hepatic lobules, most of them being located in the walls of centrolobular veins, in an endothelial position. Subcapsular cells were also shown to express monokine genes. The location of positive cells and their pattern of labelling suggested that macrophages, fibroblasts and endothelial cells were the main cell populations expressing monokine genes. In contrast, Kupffer cells, biliary epithelial cells and hepatocytes did not express monokine genes. No marker of immune activation other than monokine gene expression was detected in these histologically normal livers. The expression of the IL-1 beta gene and of the IL-6 gene may be induced by gut-derived LPS, and could play a role in the modulation of hepatocyte function in normal liver.

Gene Expression↗
PubMed1992

Reinfection of liver graft by hepatitis C virus after liver transplantation.

We have investigated hepatitis C virus (HCV) viremia before and after orthotopic liver transplantation (OLT). 38 patients were examined; 16 were anti-HCV positive and 22 anti-HCV negative pre-OLT in a RIBA-2 test (Ortho Diagnostic Systems Inc., Westwood, MA). HCV-RNA was detected using a modified nested polymerase chain reaction in 14/38 and 10/38 patients before and after OLT, respectively. 7 of these 14 subjects who were HCV-RNA positive before OLT were also positive for serum hepatitis B surface antigen. After OLT, six patients became HCV-RNA positive, likely as a result of transfusions, while four developed a probable recurrence of HCV infection. Infection of the liver graft by the same strain of HCV was indeed demonstrated by sequence analysis of a hypervariable domain (in the envelope region) in two cases. This establishes the possibility of HCV recurrence and shows the usefulness of polymerase chain reaction as the only assay currently capable of identifying HCV infection after OLT.

Base Sequence↗
PubMed1992

The Paul Brousse liver transplant series 1989 to 1992: new trends in the last four years.

In the last four years, 551 liver transplantations have been performed at the Paul Brousse center, for a total of 840 liver transplantations performed from 1984 to 1992. Several changes have been observed in the field of liver transplantation in the past years. The field of immunosuppression was marked mainly by the advent of FK506 as a preventive treatment of rejection and as a treatment of cortico-resistant rejection. Results are still under analysis. From the surgical viewpoint, the main modification was the advent of UW solution, which extends cold ischemic time. However, our policy was to maintain the cold ischemic time at less than 12 hours. Primary indications for liver transplantations have changed with an increase in the rate of patients transplanted for cirrhosis related to hepatitis virus infection: from 24% in the period 1984-1988 to 42% in the period 1989-1992. The difference was due mainly to HCV-related cirrhosis, which increased from 8% to 20%. Alcoholic cirrhosis was a rare indication in the period 1989-1992 (3.4%); however, it was an increasing indication in the last 2 years. In order to improve the long-term results, major attention was given to the recurrence of initial liver disease. In patients transplanted for HBsAg-positive liver disease, long-term passive anti-HBs immunoprophylaxis was administered, which reduced the rate of HBV recurrence in patients without HBV replication before transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Academic Medical Centers↗
PubMed1992

[Kaposi's sarcoma following liver transplantation].

A 54-year-old man developed Kaposi's sarcoma 2 months following orthotopic liver transplantation for hepatitis B-associated liver cirrhosis. At that time he was on combined immunosuppressive therapy (azathioprine, prednisone and cyclosporine A). The disease is very prevalent among immunosuppressed patients following renal transplantation, but is considered to be relatively rare following liver transplantation. The patient ran a relatively benign course without organ involvement and with only the skin disease. This is the first case of Kaposi's sarcoma following liver transplantation reported in Israel.

Humans↗
PubMed1992

[Pregnancy after hepatic transplantation. 17 pregnancies].

The number of orthotopic liver transplantations (OLT) is increasing and longterm survival is improving. More women recipients may choose to become pregnant. We report a one-center experience with the course and outcome of 17 pregnancies in 17 liver transplant out of 675 OLT since 1985. 10 women delivered of 10 healthy infants at 38 +/- 1.5 week's gestation. There was no preterm delivery and the mean birth weight was 2.990 +/- 370 g, birth weight was adequate for gestational age in any case. Four cesarean sections were performed for obstetrical indications. No congenital anomalies occurred in the children. Hypertension occurred in 2 out of twelve patients and appeared as the main complication to deal with. There was one case with graft function impairment at 37 weeks' gestation. One uncomplicated pregnancy is ongoing at 29 weeks' gestation. There were 4 spontaneous and 2 therapeutic abortions for impaired liver function. Pregnancy is successful in a large proportion of these patients but must be planned and managed as high-risk situations by an obstetrician and a specialist of the liver transplant. Pregnancy should be advised against in patients with poor liver function or active viral infection; a 12 months interval from OLT to pregnancy is since to be the minimal requirement. Post-transplant immunosuppressive therapy consisted of azathioprine, corticosteroids and ciclosporin A, and was maintained throughout pregnancy. Genetic counselling should be provided when the primary liver disease is inherited. This being said, as shown by the results of our study and those reported in the literature, pregnancy is not only feasible but also successful in a large proportion of OLT recipients.

Abortion, Spontaneous↗
PubMed1991

[Liver transplantation in non-alcoholic cirrhosis in adults].

Liver transplantation has become the treatment of end-stage cirrhosis. The results of transplantation should be improved by a better knowledge of prognostic criteria in cirrhosis, which would help in timing the transplantation, and by a better prevention of graft reinfection with hepatitis viruses.

Adult↗
PubMed1991

Passive immunoprophylaxis after liver transplantation in HBsAg-positive patients.

110 HBsAg-positive patients underwent orthotopic liver transplantation and received long-term anti-hepatitis B virus (HBV) passive immunoprophylaxis with anti-HBs immunoglobulin. During a mean follow-up period of 20 months, all patients became HBsAg negative after transplantation but circulating HBsAg reappeared in 25 (22.7%). Overall 1-year survival was 83.6% and overall 2 year actuarial recurrence of HBsAg was 29% (59% after posthepatitis B cirrhosis, 13% after posthepatitis B-delta cirrhosis, and 0% after fulminant hepatitis B). Patients with HBV cirrhosis who were HBV-DNA positive had a much greater risk of HBsAg recurrence than patients who were HBV-DNA negative (96% vs 29% at 2 years). Reappearance of HBsAg was associated with evidence of HBV replication and abnormal histological findings in the graft. Long-term passive anti-HBV immunoprophylaxis significantly reduced HBV reinfection and improved survival in patients without evidence of active HBV replication before orthotopic liver transplantation.

Adolescent↗
PubMed1991

[Liver transplantation and the major histocompatibility complex].

We have carried out a retrospective study over 308 liver transplant patients (31 of them have had a retransplantation) in Professor Bismuth's Department at Paul Brousse Hospital. The purpose of the study was a search for the possible effect of donor/recipient major histocompatibility complex on the evolution of the transplantation. We chose to study four parameters: early acute rejection; chronic rejection; retransplantation cases and death frequency; graft survival. We observed the following: for HLA A locus: in cases of total or partial compatibility there are more moderate early acute rejections than in the case of incompatibility (p less than 0.02); for HLA B locus: in the case of total compatibility there are more chronic rejections than in cases of partial or total incompatibility (p less than 0.03); for joint A and B locus: the results are similar to those of A locus (p less than 0.03); for HLA class I: we observed no effect either on graft survival or on retransplantation cases or on death frequency; for HLA DR: we did not find any effect on the studied parameters. Considering the low statistical significance of these results and in order to confirm our analysis, we have started a prospective study in collaboration with two other European Transplantation Centers.

Graft Rejection↗
PubMed1991

A comparative study of X-ray pelvimetry and CT pelvimetry.

In this study 24 patients who had conventional erect lateral X-ray pelvimetry had a CT pelvimetry done after delivery to complete the pelvimetry views. The erect lateral pelvimetry was read independently by a Consultant Radiologist, Consultant Obstetrician and a Medical Officer training in Obstetrics and Gynaecology. Using CT pelvimetry as the 'gold standard' (as the error of measurement was known with the machine used) the 3 readings were compared. There was no statistical difference in the values suggesting that X-ray pelvimetry is comparable to CT pelvimetry. However CT pelvimetry is preferred, if available, because of the lower dose of radiation involved, more comfort for the patient and shorter time in performing the procedure. Measurements done are easily read directly from the CT console.

Adolescent↗