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Biomedical subjects

B Charpentier

Publications and source records attributed to B Charpentier.

At least 55 records · Page 3Linked to original sources
PubMed2000

Hemolytic uremic syndrome. Recurrence after renal transplantation. Groupe Coopératif de l'Ile-de-France (GCIF).

Hemolytic uremic syndrome (HUS) is an uncommon cause of end-stage renal failure in adults, and few data are available concerning the outcome of renal transplantation in these patients. We conducted this retrospective multicentric study to appreciate the outcome of adult renal transplant recipients whose primary disease was HUS. Sixteen patients, transplanted between 1975 and 1995, were included in the study. In each case, initial diagnosis of HUS was documented by a kidney biopsy. These 16 patients received a total of 25 allografts: 1 graft for 9 patients, 2 grafts for 5 patients, and 3 grafts for 2 patients. Nine patients (56%) developed definite clinical and pathologic evidence of recurrence on at least 1 graft. Four additional patients (25%) demonstrated only some clinical or pathologic evidence of recurrence which could not be distinguished from acute vascular rejection. Three patients had no sign of recurrence of the initial disease. The 1-year graft survival rate was 63% and the 5-year graft survival rate was 18.5%. In the group of patients with proven or possible recurrence (n = 13), the 1-year and 5-year graft survival rates were 49% and less than 10%, respectively. The recurrence was an early event, occurring before the end of the first month after transplantation in half the cases. The recurrence rate was 92% in non-nephrectomized patients and 50% in patients with bilateral nephrectomy. In the literature, 71 adult patients with primary HUS had received a total of 90 kidney grafts. Among them, 54% had a recurrence on their graft, which was diagnosed in 52% of the kidney transplants. It is note-worthy that when data from the literature are pooled with our results, the rate of recurrence appears to be significantly lower in binephrectomized patients than in patients with their native kidneys at the time of transplantation (5 of 14 versus 27 of 35 patients, respectively, p = 0.0155). By univariate analysis, no other risk factor for recurrence could be identified. Treatment with cyclosporine A did not influence the recurrence rate. We conclude that recurrence of HUS after renal transplantation is a frequent, early, and severe complication, leading rapidly to graft loss. Prospective studies are needed to confirm that bilateral nephrectomy prior to transplantation decreases the rate of recurrence.

Actuarial Analysis↗
PubMed2000

Analysis of primer residue from lead free ammunition by X-ray microfluorescence.

In forensic science, the analysis of gunshot residues was traditionally done by the detection of lead (Pb), antimony (Sb) and barium (Ba) usually found in a primer. However, the recent development of lead-free ammunition represents a new challenge for ballistic specialists. This analysis study gunshot residues from primers and ammunitions in the area surrounding bullet holes, a very important tool to determine the shooting distance. The ammunitions used were 9 mm Luger and .38 spl + p calibers, where lead in the primer was replaced with strontium (Sr) and where the lead bullet was plated with copper (Total Metal Jacket). Gunshot analysis results were obtained using an energy dispersive X-ray microfluorescence spectrometer. The method allows the detection and quantification of strontium residues on the target up to a distance of 45 cm.

Criminology↗
PubMed2000

[Diffuse colitis associated with mycophenolate mofetil treatment: apropos of 1 case].

Mycophénolate mofétil (MMF) or Cellcept is a potent immunosuppressor that inhibits purin synthesis used to prevent human allograft rejection. The most important secondary effects include haematological and intestinal disorders. Among them, diarrhea is the most common. It is dose-dependant and appears commonly during the first 2 months of treatment. Its physiopathology remains unclear. We reported a case of colitis, 6 months after a kidney transplantation. The patient was treated since day 2 with 2 grams per day of MMF. Morphological analysis showed a diffuse colitis from the coecum to the rectum. Histological samples confirmed a colitis with atrophic crypts but with mucosal secretions and some cryptic abscesses. No granuloma or CMV inclusion was founded. Histochemical immunostaining for CMV was negative. Finally, symptoms regressed within 5 days after tapering down MMF dose in association with metronidazole treatment. The role of MMF in inducing colitis is discussed.

Aged↗
PubMed1999

Peripheral blood T cells generated after allogeneic bone marrow transplantation: lower levels of bcl-2 protein and enhanced sensitivity to spontaneous and CD95-mediated apoptosis in vitro. Abrogation of the apoptotic phenotype coincides with the recovery of normal naive/primed T-cell profiles.

T-cell reconstitution after bone marrow transplant (BMT) is characterized, for at least 1 year, by the expansion of populations of T cells with a primed/memory phenotype and by reverse CD4/CD8 proportions. T lymphocytes from 26 BMT patients (mostly adults) were obtained at various times after transplantation (from 45 to >/=730 days) and were tested for susceptibility to spontaneous apoptosis and anti-Fas triggered apoptosis in vitro. Substantial proportions of CD4(+) and CD8(+) cells generated during the first year after transplantation, but not by day 730, exhibited in these assays decreased mitochondrial membrane potential (triangle upPsim) and apoptotic DNA fragmentation. The apoptotic phenotype tended to disappear late in the follow-up period, when substantial absolute numbers of naive (CD45RA(+)/CD62-L(+)) T cells had repopulated the peripheral blood compartment of the BMT patients. The rate of spontaneous cell death in vitro was significantly correlated with lower levels of ex vivo Bcl-2 protein, as assessed by cytofluorometry and Western blot analysis. In contrast, the levels of Bax protein remained unchanged, resulting in dysregulated Bcl-2/Bax ratios. Cell death primarily concerned the expanded CD8(+)/CD45R0(+) subpopulation, although CD45R0(-) subpopulations were also involved, albeit to a lesser extent. These results show that the T-cell regeneration/expansion occurring after BMT is accompanied by decreased levels of Bcl-2 and susceptibility to apoptosis.

Adult↗
PubMed1999

Sirolimus (rapamycin)-based therapy in human renal transplantation: similar efficacy and different toxicity compared with cyclosporine. Sirolimus European Renal Transplant Study Group.

BACKGROUND: Sirolimus (rapamycin) is a potent immunosuppressant with a mechanism of action different from cyclosporine (CsA) or tacrolimus. METHODS: In 11 European centers, first cadaveric renal allograft recipients were randomized to CsA (n=42) or sirolimus (n=41). Dosing of these agents was concentration-controlled and open-labeled. All patients received corticosteroids and azathioprine. RESULTS: At 12 months, graft survival (98% sirolimus vs. 90% CsA), patient survival (100% vs. 98%), and incidence of biopsy-confirmed acute rejection (41% vs. 38%) were similar. Serum creatinine was lower with sirolimus, significantly (P< or =0.05) so at 3 and 4 months, and serum uric acid and magnesium were normal. Laboratory abnormalities reported significantly more often with sirolimus included hypertriglyceridemia (51% vs. 12%), hypercholesterolemia (44% vs. 14%), thrombocytopenia (37% vs. 0%), leukopenia (39% vs. 14%), and, of lesser importance, increased liver enzymes and hypokalemia. These abnormalities improved 2 months after transplantation when the sirolimus target trough level was lowered from 30 to 15 ng/ml. Occurrence of cytomegalovirus was comparable (14% vs. 12%); incidences of herpes simplex (24% vs. 10%, P=0.08) and pneumonia (17% vs. 2%, P=0.03) were higher with sirolimus. No gingival hyperplasia was seen with sirolimus, tremor was rare, and hypertension was less frequent (17% vs. 33%). Two malignancies were observed with CsA and none with sirolimus. CONCLUSIONS: Results at 12 months suggest that sirolimus can be used as base therapy in the prophylaxis of acute renal transplant rejection, and has a safety profile that differs from CsA.

Adult↗
PubMed1999

Growth hormone prevents human monocytic cells from Fas-mediated apoptosis by up-regulating Bcl-2 expression.

Apoptosis and particularly Fas-mediated apoptosis has been proposed to play a key role in controlling monocyte homeostasis. We and others have documented the regulatory function of human growth hormone (hGH) on monocytic cells, which prompted us to investigate the role of hGH on their response to Fas antigen cross-linking. Using human promonocytic U937 cells constitutively producing hGH upon gene transfer and human primary monocytes cultured in the presence of recombinant hGH, we demonstrated that hGH diminished Fas-mediated cell death by enhancing the expression of the antiapoptotic oncoprotein Bcl-2 as well as the level of bcl-2alpha mRNA. In parallel, we established that overexpression of Bcl-2 through gene transfer into normal U937 cells also diminished Fas-induced apoptosis. Further, as a result of Bcl-2 overexpression, we found that hGH greatly depressed Fas-induced activation of the cysteine protease caspase-3 (CPP32), which in turn affected the cleavage of poly(ADP-ribose) polymerase. Altogether, these data provide evidence that hGH mediates its protective effect through a Bcl-2-dependent pathway, clearly a crucial step in enhanced survival of monocytic cells exposed to Fas-induced death.

Apoptosis↗
PubMed1999

Human parvovirus B19 infection in organ transplant recipients.

We report a 61-yr-old kidney transplant recipient with human Parvovirus B19 (HPV B19) infection presenting as a severe pancytopenia 1 month after transplantation. Bone marrow aspiration revealed severe erythroid hypoplasia with giant and dystrophic proerythroblasts. Bone marrow cells were positive for HPV B19 DNA detected by polymerase chain reaction (PCR). Pancytopenia resolved shortly after administration of intravenous immunoglobulins. Nineteen cases of HPV B19 infection in organ transplant recipients have been so far reported in the literature. Immunocompromised patients should be considered at risk from developing symptomatic HPV B19 infections. In such patients, specific anti-HPV B19 IgM and IgG antibodies may be absent or transient and therefore their negativity cannot rule out the diagnosis of HPV B19 infestation. Bone marrow smear morphological findings may suggest the diagnosis but testing for viral DNA by PCR is mandatory. Patients may spontaneously recover. However, since specific anti-viral therapy is not currently available, intravenous immunoglobulin administration appears to be the more efficacious treatment.

DNA, Viral↗
PubMed1998

Caspase-independent cell death induced by anti-CD2 or staurosporine in activated human peripheral T lymphocytes.

We examined the effects of the cell-permeable, broad spectrum peptide caspase inhibitors, benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD.fmk), and BOC-Asp(OMe)-fluoromethyl ketone (BOC-D.fmk), on apoptosis induced by anti-CD2, anti-Fas, and the protein kinase inhibitor staurosporine in activated human peripheral T lymphocytes. We monitored ultrastructural, flow cytometric, and biochemical apoptotic changes, including externalization of phosphatidylserine, cleavage of poly(ADP-ribose) polymerase (PARP) and lamins, activation of caspase-3 and caspase-7, decrease in mitochondrial membrane potential, and DNA fragmentation. Z-VAD.fmk and BOC-D.fmk completely inhibited all the biochemical and ultrastructural changes of apoptosis in anti-Fas-treated cells. In marked contrast, neither Z-VAD.fmk nor BOC-D.fmk inhibited CD2- or staurosporine-mediated cell shrinkage, dilatation of the endoplasmic reticulum (seen in anti-CD2-treated cells), externalization of phosphatidylserine, and loss of mitochondrial membrane potential that accompanied cell death. However, these inhibitors did inhibit the cleavage of PARP and lamins and the formation of hypodiploid cells, and partially inhibited chromatin condensation. These results demonstrate that in activated T cells, anti-CD2 and staurosporine induce a caspase-independent cell death pathway that exhibits prominent cytoplasmic features of apoptosis. However, caspase activation is required for the proteolytic degradation of nuclear substrates such as PARP and lamins together with the DNA fragmentation and extreme chromatin condensation that occur in apoptotic cells.

Amino Acid Chloromethyl Ketones↗
PubMed1998

Potent apoptotic signaling and subsequent unresponsiveness induced by a single CD2 mAb (BTI-322) in activated human peripheral T cells.

Manipulation of CD2 molecules with CD2 mAb pairs has been shown to deliver apoptotic signals to activated mature T cells. We show that BTI-322, a CD2 mAb directed at a peculiar epitope of CD2, can trigger on its own the apoptotic death of IL-2-activated peripheral T cells and of OKT3-stimulated T cells, contrasting in this respect with a series of other mouse or rat CD2 mAb. F(ab')2 fragments were as potent as the whole Ab. BTI-322-induced apoptosis proceeded in a few hours and was independent of the Fas/Fas ligand system. Less than 5 ng/ml of BTI-322, added at the beginning of culture, were able to eliminate within 4 days most CD3+ cells from OKT3- and IL-2-stimulated lymphocytes, the only cells remaining being CD16+CD2- NK cells. T cell proliferative responses induced by a mitogenic CD2 mAb pair or by PHA-P (which mainly binds to CD2) were not inhibited by BTI-322. In this case, the apoptotic effect was successfully counteracted by simultaneous enhancement of T cell divisions. Thus, the killing effect of BTI-322 was most effective when T cells were exclusively stimulated through the CD3/TCR complex. Apoptosis of the responding T cells may explain why T cells recovered from a primary MLC performed in the presence of BTI-322 responded to third party cells but not to the primary stimulatory cells. These data constitute the rational basis for the use of BTI-322 for inducing tolerance in human allotransplantation.

Animals↗