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Biomedical subjects

F Pichon

Publications and source records attributed to F Pichon.

15 recordsLinked to original sources
PubMed1992

[Relapse prevention in liver transplant patients treated for liver involvement due to hepatitis B virus].

Controversy surrounds the indication of liver transplantation in patients with hepatitis B virus infection. The major problem is the very high risk of infection of the graft. Some investigators have suggested that the presence of HBsAg is a contraindication to liver transplantation. Between February 1975 and December 1990, 178 HBs positive patients were transplanted at Paul Brousse Hospital in Professor H. Bismuth's Department, 137 for post hepatitis cirrhosis and 41 for fulminant hepatitis. Since April 1984 we have decided long term immunoprophylactic therapy for all patients with HBs infection. But only from August 1987 our supply of purified anti HBs immunoglobulin has been adequate to treat all our patients according to the following protocol: 10.000 IU during the peroperative phase, 10.000 IU immediately after intervention, 10.000 IU every day for the first 6 days, 10.000 IU when the anti HBs levels were under 150 IU/l. One hundred thirty-nine patients were treated by this method. 110 cleared HBs antigen from their sera and their liver were biologically and histologically free of B virus infection. 29 patients showed reappearance of HBs antigen in their sera and nearly all of them developed objective, histologically confirmed, graft lesions. These lesions are those of classical infection: acute hepatitis, active chronic hepatitis and cirrhosis. So 79% of patients were successfully treated with a follow up of 45 months to 6 months. We also studied the prognostic factors under treatment. The study shows: in the case of fulminant hepatitis, 93% success versus 77% in post hepatitis cirrhosis; in the case of Delta superinfection, 94% success versus 66% with pure B infection; in the absence of HBVDNA in the patient's sera before transplantation, 92% success versus 20% in the presence of HBVDNA. For a better understanding of the overall results, the two following parameters have to be considered: some patients relapsed after stopping their treatment, some other patients, despite repositivation of HBs antigen in their sera showed a paradoxal good evolution. These considerations enable us to obtain HBVDNA positive patients: 10% success, HBVDNA negative patients: Fulminant hepatitis: 100% success B Delta post hepatitis cirrhosis: 100% success B post hepatitis cirrhosis: 92% success.

Hepatitis B↗
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↗
PubMed1989

Autoregulation of MeWo metastatic melanoma cell growth: characterization of intracellular (FGF, MGSA) and secreted (PDGF) growth factors.

MeWo melanoma cells (clone LC1) secrete a potent mitogenic activity susceptible to reinitiate DNA replication in quiescent rodent fibroblasts (CCL39, NRK-49F, NIH-3T3) but not in BHK-21 kidney cells. This activity appears to be closely related to platelet-derived growth factor (PDGF) based on 1) its cationic nature, heat and acid resistance, but sensitivity to reducing agents; 2) its apparent molecular weight (33 kDaltons) as estimated by Biogel filtration, once dissociated from binding proteins by mild acidic treatment; 3) its weak affinity for heparin; and 4) its ability to compete with 125I-PDGF for binding to human and rodent fibroblasts, and to be recognized by anti-PDGF antibodies. Although MeWo cells coexpress the PDGF-A and PDGF-B (c-sis) chain gene transcripts, the secreted product shows reactivity on CCL39 fibroblasts more compatible with the PDGF-BB than with the PDGF-AB isoform. MeWo cell lysates contain activities that bind moderately and strongly to heparin-Sepharose, being eluted with 1.0 and 2.0 M NaCl, respectively. The latter may correspond to basic fibroblast growth factor (basic FGF), consistent with the expression of basic FGF gene mRNAs. The former has not been fully characterized and is probably not the product of the acidic FGF gene. In addition, MeWo cells react positively with the FB2 AH7 antibody, thus indicating that they elaborate material similar to melanoma growth-stimulating activity (MGSA). MeWo cells proliferate in serum-free medium in a cell-density-dependent fashion, both in liquid and semisolid cultures. Their division is modestly enhanced by basic FGF and by human and porcine PDGF but not by the factors that they release. However, the absence of demonstrable 125I-PDGF binding sites on MeWo cells, in conjunction with their lack of sensitivity to suramin growth inhibition, suggests that the secreted PDGF does not act as an autocrine factor. Instead, the autonomous proliferation of MeWo melanoma cells may result from the concerted action of basic FGF and MGSA, which are mostly cell-associated.

Animals↗
PubMed1988

Pseudomonas aeruginosa sepsis presenting as peripheral subcutaneous nodules. Report of 2 cases.

Two patients developed disseminated subcutaneous nodules with febrile illness. In both cases, Pseudomonas aeruginosa was isolated from the lesions; blood cultures yielded the same organism in one case, and were negative in the other. The portal of entry was thought to be a jugular hemodalysis catheter in the first case and a necrotic zoster complicating lymphoma in the second case. Both patients' condition improved with antibiotic therapy and the Pseudomonas nodules resolved without surgical drainage.

Aged↗
PubMed1988

Progressive relaxation of Go-arrest controls and altered responsiveness to insulin, EGF and thrombin in CCL39 lung fibroblasts over-expressing myc and ras oncogenes.

Factor-dependent hamster lung fibroblasts (CCL39) were transfected with plasmid vectors expressing normal Ha-ras, T24 Ha-ras, V-Ki-ras or myc oncogenes placed under the transcriptional control of potent viral or inducible (metallothionein-I) promoters. The rate at which clonal isolates proliferated in monolayer cultures in serum-free medium or in response to progression (insulin, EGF) and competence growth factors (alpha-thrombin) was found to vary according to the level of oncogene expression. Low levels of T24 ras gene did not abrogate Go-arrest controls but rendered CCL39 cells responsive to both insulin and EGF. Moderate levels (3- to 10-fold) of T24 and Ki-ras genes induced autonomous growth in serum-free medium and attenuated the cell responsiveness to all three factors. Growth of highest ras expressors was enhanced by low (less than 100 microM) concentrations of suramin, and was partially or not inhibited at higher concentrations. In contrast, EGF but not insulin, was able to recruit quiescent cells expressing moderate (less than or equal to 5-fold) myc levels. Higher levels conferred growth autonomy as well as hypersensitivity to insulin, EGF and thrombin. Suramin abolished the self-replication of such myc cells, thus suggesting an autocrine mechanism of proliferation. Hence, both myc and ras genes provided CCL39 cells with distinct growth competence functions which enabled these cells to respond overall more efficiently to functionally distinct classes of mitogens, or to sustain a completely autonomous replication, depending on the abundance of their respective products. Negative autoregulatory mechanisms may additionally be set into motion in this system when activated ras oncogenes are excessively expressed.

Animals↗
PubMed1979

[Disinsertion of the subscapularis muscle in the treatment of obstetric paralysis of the upper limb (author's transl)].

Proximal disinsertion of the subscapularis is an effective operation in the correction of an abnormal position in internal rotation of the shoulder. Such a decision should be taken only if the head of the humerus is still well rounded. Restoration of movement by muscular transfer of active external rotation is performed in subsequent months only if the teres minor and infraspinatus muscles do not recover spontaneously.

Adolescent↗
PubMed1978

[Approaches to the hip in the child. I. Partial approaches (author's transl)].

It exist multiple approaches to the hip in the child. This first section is devoted to a description of those approaches which offer only limited exposure of the joint. Alongside the medial approach used for joint puncture and the obturator approach, scarcely of any use, three important approaches respecting the integrity of the gluteal muscles may be used: those of Hueter and of Watson-Jones, to the anterior aspect of the neck of the femur and that of Moore, approaching its posterior aspect.

Child↗
PubMed1978

[Experimental transection of the spinal cord (author's transl)].

Twenty-three dogs underwent a complete transection of the spinal cord at L 1 level. Section was followed in eighteen animals by reconstruction effected through suture of the arachnoide with the aid of monofilament 10 X 0 thread. The operation was in all cases concluded by an osteosynthesis with metallic material in order to prevent any movements in the operated site, and a tight dural closure was achieved in order to prevent propagation of any epidural hematoma or secondary granuloma. This technique did not prevent an unfavorable evolution of the suture, which demonstrated three different morphological features:--necrosis of the spinal cord cut ends with secondary formation of a transverse cyst;--secondary infiltration of the operated focus by a fibrous scar growing from the inner aspect of the dura;--failure of axon regeneration through this fibrous block in spite of noteworthy proliferation of axons coming from the dorsal roots. A critical analysis of those results led to a comparaison with various previous works on the same subject. The most recent of these works have led to promising prospects which need confirmation.

Animals↗
PubMedDate not supplied

[Progressive bone lengthening using Wagner's technique (author's transl)].

The authors have reviewed the results of 30 surgical procedures of progressive bone lengthening using the Wagner's technique. In 28 cases, internal fixation was applied at the end of the lengthening period. There were 17 femora and 13 tibae operated on. In 6 cases, lengthening was associated with a correction of the alignment of the femur, and in 2 cases was associated with the treatment of a non-union of the tibia. Complications are described; they were found to be relatively rare.

Adolescent↗