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Biomedical subjects

D Samuel

Publications and source records attributed to D Samuel.

At least 109 records · Page 6Linked to original sources
PubMed1996

Incidence of rejection and infection after liver transplantation as a function of the primary disease: possible influence of alcohol and polyclonal immunoglobulins.

A retrospective analysis was undertaken to determine if the incidence, timing, and severity of acute and chronic rejection were influenced by the primary disease necessitating transplantation. Of the 875 liver transplantations performed between 1984 and 1992, 768 were primary transplantations and 107 were retransplantations. Among the former, 330 patients that were liver transplant recipients for a chronic liver disease without cancer in the native liver received an ABO-compatible and cross-match-negative graft and were given a cyclosporine- or tacrolimus-based immunosuppression. These included primary biliary cirrhosis (PBC, 66 patients), primary sclerosing cholangitis (PSC, 23 patients), alcoholic cirrhosis (ALC, 21 patients), autoimmune cirrhosis (AIC, 17 patients), hepatitis B virus-induced cirrhosis (HBV-C, 116 patients) and hepatitis C virus-induced cirrhosis (HCV-C, 87 patients). The incidence of acute (48% +/- 3% [SE] at 1 year) and chronic rejection (10% +/- 2% at 3 years) was comparable in patients who have undergone transplantation for PBC, PSC, AIC, and HCV-C. However, the incidence of acute (but not chronic) rejection was significantly lower in patients who have undergone transplantation for ALC (29% at 1 year). This reduced incidence of acute rejection was associated with an increased incidence of bacterial infections. In patients who have undergone transplantation for HBV-C (the majority of whom had received long-term anti-hepatitis B surface antigen [HBs] immunoglobulins), the incidence of both acute (21% at 1 year) and chronic rejection (0% at 3 years) was significantly lower, whereas the incidence of septic complications was comparable with that in the other groups. The incidence of acute rejection in patients who have undergone transplantation for nonviral disease receiving polyclonal human anti-cytomegalovirus (CMV) immunoglobulins was also significantly lower than that of patients who did not receive the immunoglobulins (19% vs. 48% at 3 months; P = .01), and this was identical to that of patients who have undergone transplantation for viral disease receiving polyclonal human anti-HBs immunoglobulins (19% at 3 months). These results show that the risk of rejection is unequal among patients, being lower in patients who have undergone transplantation for ALC (probably as a result of a state of nonspecific hyporesponsiveness) and in patients who have undergone transplantation for HBV-C (possibly as a result of long-term administration of polyclonal human immunoglobulins).

Adult↗
PubMed1996

Liver transplantation in Europe for patients with acute liver failure.

Approximately 11% of all liver transplants performed in Europe are for acute liver failure, with one-year patient survival rates ranging between 50% and 75%. This review summarizes the selection, perioperative management, and outcome of patients transplanted for acute liver failure, with particular reference to the experience at the Hôpital Paul Brousse in Paris and at King's College Hospital, London. In both centers, the decision to proceed to liver transplantation is based on criteria that predict a survival of less than 20% with medical management alone. Infectious complications and cerebral edema remain the most common causes of death, and highlight the importance of intensive monitoring and early treatment of perioperative complications. In selected patients, auxiliary partial orthotopic liver transplantation may be a therapeutic option, with the potential for native liver generation and eventual immunosuppression withdrawal in approximately two-thirds of patients.

Europe↗
PubMed1996

Hepatic failure associated with imipramine therapy.

Imipramine is an antidepressant drug that is rarely associated with mild liver function abnormalities. These are usually minor and transient liver enzyme elevations which return to normal levels upon discontinuation of the drug. We describe a 48-year-old male who developed subfulminant hepatic failure after imipramine usage, with complete recovery within three months after discontinuation of the drug.

Antidepressive Agents, Tricyclic↗
PubMed1996

Induction of helical conformation in all beta-sheet proteins by trifluoroethanol.

The effect of 2,2,2-Trifluoroethanol (TFE) on the structure of five all beta-sheet proteins, isolated from the venom of the Taiwan cobra (Naja naja atra), is studied. In all the toxins used, it is observed that significant amount of alpha-helix is induced at higher concentrations of TFE. In all these proteins, the induction of helical conformation and disruption of the tertiary structure seem to occur simultaneously. The structural transitions induced by TFE in reduced and denatured protein appear to be different from those observed in the native protein(s). In our opinion, the findings reported herein could have significant implications on research in the area of protein folding.

Circular Dichroism↗
PubMed1996

Auxiliary partial orthotopic liver transplantation for fulminant hepatitis. The Paul Brousse experience.

OBJECTIVE: The authors objective is to report their experience with auxiliary partial orthotopic liver transplantation in fulminant hepatitis (FH) and to discuss the principles that may help in its safe application. SUMMARY BACKGROUND DATA: Auxiliary partial orthotopic liver transplantation is an attractive therapeutic method in FH because it provides hepatic function, whereas the remaining native liver is given the possibility to recover. Despite early encouraging reports, its place in the treatment of FH remains to be defined. METHODS: Evaluation of 5 cases of FH treated with auxiliary partial orthotopic liver transplantation from a collective of 22 transplantations for 35 cases of FH referred to the authors' center from January 1994 to November 1995. The grafts were one left lobe, two left livers, and two right livers. RESULTS: The native liver regenerated in three patients: one with Reye's syndrome who died of irreversible neurologic damage, one with FH caused by the hepatitis B virus who is alive 20 months after ABO incompatible graft removal, and one with FH caused by the hepatitis A virus who had her graft removed at 4 months. In two patients, regeneration did not occur: one with drug-induced FH who died of sepsis 3 months after surgery and one with FH of unknown origin who was retransplanted with a standard liver transplantation at 4 months for uncontrollable biliary rejection of an ABO incompatible graft (alive at 10 months). Two of the three patients who survived suffered severe neurologic complications. CONCLUSIONS: Auxiliary partial orthotopic liver transplantation is an attractive treatment for FH, especially in the presence of good prognostic factors for native liver regeneration: a young patient, rapid onset of the disease, and viral hepatitis. It should be considered cautiously in patients with advanced encephalopathy. By providing a smaller mass of liver tissue than with standard orthotopic liver transplantation, and as a more complex operative procedure, auxiliary partial orthotopic liver transplantation may not be as effective in arresting the progression of neurologic damage.

Adolescent↗
PubMed1996

Development of a simplified polymerase chain reaction-enzyme immunoassay for the detection of Chlamydia pneumoniae.

The 16S rRNA genes of two Chlamydia pneumoniae and two C. psittaci strains of different serovars were sequenced then compared to previously reported Chlamydia 16S rRNA gene sequences. Chlamydia pneumoniae-specific regions were identified and specific primers for nested PCR were synthesized. Nested PCR reactions were performed, in a single tube, by varying the annealing temperature of the amplification cycles. The initial thermal cycles were selected to allow annealing and extension of only the outer primer pair, whilst in later cycles a temperature that allowed inner primer annealing was employed. The inner primers were labelled, one with biotin and the other with fluorescein and consequently the dual labelled amplicon could be immobilized onto antibiotin-coated microtitre plates and detected colorimetrically via an antifluorescein-enzyme conjugate. The assay was found to be sensitive and specific. No cross reactions were observed with C. trachomatis, C. psittaci or other common respiratory pathogens.

Chlamydophila pneumoniae↗
PubMed1996

Recurrent aspergilloma of the frontoethmoid sinus in a non-immunocompromised patient.

Management of invasive aspergillosis of the paranasal sinuses requires sufficient experience to initiate appropriate investigations and then utilize the correct treatment protocol. Computed tomography (CT) or magnetic resonance imaging (MRI) is essential to show the extent of the disease and diagnosis is confirmed by histological analysis. Aspergillus flavus is a ubiquitous soil saprophyte in the Sudan and is responsible for many cases originating from this area. The literature is reviewed and treatment options discussed.

Adult↗
PubMed1996

Audit of pain after nasal surgery.

In our department, nasal packs have traditionally remained in place for a period of 24 h after routine elective nasal surgery. We decided to determine whether reducing the duration of nasal packing from 24 h to 2 h would reduce postoperative pain without a concomitant increase in haemorrhagic complications. A series of 72 patients undergoing elective nasal surgery were randomised to have either nasal packs for 24 h (n = 39) or for 2 h (n = 33). Pain was assessed using a visual analogue scale with the nasal packs in place and on their removal. The incidence of haemorrhage was noted. The results showed a significant decrease in mean pain score (MPS) with the packs in place, from 3.4 (range 0.8-6.8) to 1.16 (range 0-2.5); (P < 0.001) and also on pack removal from 5.3 (range 1.2-7.9) to 2.6 (range 0-5.4); (P < 0.05). There was no postoperative haemorrhage in either group. A new standard of 2 h for routine nasal packing was set and our departmental protocols were changed accordingly. Results in a further 36 patients gave a MPS with the packs in place of 1.12 (range 0-3.2) and a MPS of 2.36 (range 0-6.7) on their removal. There was no statistical difference between these and our previous findings. We conclude that postoperative nasal packing for only 2 h rather than 24 h significantly reduces pain without a concomitant risk of haemorrhage.

Adult↗
PubMed1995

Epstein-Barr virus-related localized hepatic lymphoproliferative disorders after liver transplantation.

BACKGROUND: Localized hepatic post-transplant lymphoproliferative disease is uncommon. In such cases, lymphocyte Epstein-Barr virus (EBV) infection may promote an intrahepatic B-lymphocyte monoclonal expansion. METHODS: From 1990 to 1991, 149 patients underwent liver transplantation for various liver failures. Immunosuppressive therapy was azathioprine, cyclosporine-A, and methylprednisolone. Rejection episodes were treated by methylprednisolone bolus injection with or without OKT3 therapy. Three patients (2%), aged 38, 50, and 47 years, developed lymphoproliferative disease localized in the transplanted livers within 5 months of liver transplantation (a patient had been immunosuppressed for 3 years before the lymphoproliferative disease occurred within the third allografted liver). Diagnoses were obtained by fine needle aspiration. In situ hybridizations were performed with the kappa/lambda mRNA-kit FITC DAKO (DAKO Corporation, Carpenteria, CA) and the early mRNA-EBER oligonucleotide FITC DAKO: RESULTS: Lymphoproliferative diseases were all classified as diffuse polymorphic large cell lymphomas in the working formulation and considered as lymphoproliferative disorders with polymorphic large cells in the Frizzera classification. All large cells were CD20-positive, CD45-positive and CD45RO-negative. In situ mRNA light chain hybridization demonstrated monoclonality in two cases. In all three cases, EBV mRNA was detected in large cells by early mRNA-EBV (EBER) in situ hybridization. Patients were treated with doxorubicin, cyclophosphamide, vincristine, and VM26. Two patients maintained a complete remission 3 years after six cycles of chemotherapy, whereas one died of an early opportunistic infection. CONCLUSION: Epstein-Barr virus may play a special role in the pathogenesis of lymphoproliferative disorders that develop in patients who have undergone liver transplantation.

Adult↗
PubMed1995

The use of ABO-incompatible grafts in liver transplantation: a life-saving procedure in highly selected patients.

The aim of this study was to assess the long term results of 43 ABO-incompatible liver transplantations performed in 40 patients. The 5-year patient and graft survival rates were 50 and 20%, respectively. In the group of patients transplanted in emergency for fulminant or subfulminant liver failure, ABO incompatibility had no significant impact on patient survival (P = 0.09). Graft survival, however, was significantly impaired (P = 0.0002) through a greater incidence of hyperacute rejection (20%), vascular thrombosis, and biliary injury (56%). Increasing the magnitude of immunosuppression and postoperatively reducing the titer of anti A/B antibodies by plasmapheresis had little influence on the incidence of these complications and were associated with a greater incidence of septic complications. These results indicate that the use of ABO-incompatible liver grafts is a life-saving procedure in patients with life-threatening acute liver failure, but at a high price. Justification for accepting or not accepting an ABO-incompatible graft in these emergency situations depends on the personal choice in giving priority to saving the patient in an acute life-threatening condition or to giving the graft the best chance of success. To avoid this difficult choice, efforts should aim at expanding the pool of grafts available in emergency, at developing artificial support devices that could allow to safely delay transplantation, or at more efficiently controlling the humoral response.

ABO Blood-Group System↗
PubMed1995

[Viral hepatitis and liver transplantation].

Chronic liver diseases due to hepatitis viruses are the main indication for liver transplantation. Recurrence of viral infection on the liver graft is responsible for the occurrence of chronic hepatitis, liver cirrhosis, or liver failure. The risk of viral recurrence may influence the indications for liver transplantation. The risk of viral B recurrence is higher in patients transplanted for viral B liver cirrhosis than for viral B-delta liver cirrhosis, and for fulminant hepatitis B. This risk is higher in patients with active viral B replication at time of transplantation. Long-term administration of anti-HBs immunoglobulins reduces significantly the HBV recurrence rate and the related mortality, especially in patients without active HBV replication at transplantation. Middle-term results for patients transplanted for viral C related liver cirrhosis are good, but the recurrence rate of HCV infection is high. Protocols of prevention of HCV recurrence after transplantation are mandatory.

Hepatic Encephalopathy↗
PubMed1995

Influence of the genotypes of hepatitis C virus on the severity of recurrent liver disease after liver transplantation.

BACKGROUND/AIMS: Several genotypes of hepatitis C virus (HCV) have been identified by phylogenetic analysis, but their clinical relevance remains elusive. Liver transplantation for HCV-related cirrhosis offers a unique opportunity for prospective studies of this issue. METHODS: Sixty anti-HCV-positive liver recipients with precise virological and histological assessments were included. HCV genotype was determined with both type-specific capsid primers and a line probe genotyping assay. RESULTS: HCV genotype 1b was the predominant type before transplantation (40 of 60 patients); after liver transplantation, acute and chronic active hepatitis developed more frequently in these patients than in patients infected by other genotypes (31 of 40 and 24 of 40 vs. 8 of 20 and 4 of 20 patients). Actuarial rates of acute hepatitis and chronic active hepatitis were 77% and 59%, respectively, 3 years after transplantation in patients infected by type 1b and 40% (P = 0.008) and 22% (P = 0.004) in those infected by other types. There was no statistical relation between the level of HCV viremia and HCV genotypes both before and after transplantation. In contrast, after transplantation, serum HCV RNA values were significantly increased in patients who developed hepatitis after transplantation. CONCLUSIONS: This study provides direct evidence that HCV 1b is associated with more aggressive recurrent liver disease than other genotypes.

Actuarial Analysis↗
PubMed1995

Atlanto-axial subluxation (Grisel's syndrome) following otolaryngological diseases and procedures.

Grisel's syndrome is a rare condition of uncertain aetiology characterized by atlanto-axial subluxation following an infection in the head and neck region. The condition most frequently affects children and characteristically presents in the post-operative period with cervical pain and torticollis. We describe three cases and discuss the aetiology and pathogenesis. A high index of suspicion may lead to early diagnosis in its natural history thereby preventing potentially serious complications.

Adenoidectomy↗
PubMed1995

Effects of ionotropic excitatory amino acid receptor antagonists on glutamate transport and transport-mediated changes in extracellular excitatory amino acids in the rat striatum.

This study examined the effects of intrastriatal administration of ionotropic excitatory amino acid receptor antagonists on biochemical markers of excitatory amino acid transmission in the rat striatum. High-affinity glutamate uptake was measured ex vivo on striatal homogenates 15 min after the local administration of either 6,7-dinitroquinoxaline-2,3-dione (DNQX), a non-NMDA receptor antagonist, or DL-2-amino-5-phosphonopentanoic acid (AP5), a competitive NMDA antagonist, at various doses (10-500 pmol injected). DNQX induced a dose-dependent increase in glutamate uptake rate, related to an increase in the Vmax of the transport process, whereas no significant change in glutamate uptake was detected after AP5 administration. Similar results were obtained from animals subjected to excitotoxic lesion of striatal neurons by kainate administration 15 days before the injection of DNQX or AP5. In a parallel series of experiments using in vivo microdialysis we showed that DNQX (10(-5) M) in the dialysis probe diminished by approximately 30-40% the increases in the concentrations of glutamate and aspartate elicited by L-trans-pyrrolidine-2,4-dicarboxylic acid (1 mM). These data suggest that presynaptic glutamate transmission in the rat striatum may undergo facilitatory autoregulatory processes involving ionotropic non-NMDA receptors and highlight the view that transporters for glutamate may be potent regulatory sites for glutamatergic transmission.

2-Amino-5-phosphonovalerate↗