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Biomedical subjects

B Charpentier

Publications and source records attributed to B Charpentier.

At least 181 records · Page 10Linked to original sources

Recurrent essential mixed cryoglobulinemia in renal allografts. Report of two cases and review of the literature.

This report describes two patients in whom essential IgG-IgM mixed cryoglobulinemia (EMC) glomerulonephritis led to end-stage renal disease. Both patients underwent primary hemodialysis, and during the period of uremia clinical and biological manifestations of the disease fully resolved. Transplantation was performed, and in both cases cryoglobulinemia quickly recurred (30 days and 6 months after transplantation, respectively) with clinical renal and extrarenal flare, and reappearance of the biological markers of the disease (decrease in C3 and C4 components of serum complement, detection of rheumatoid activity and of cryoglobulinemia in the serum). The literature on EMC glomerulonephritis leading to end-stage renal disease is reviewed. Factors that may have contributed to extinguishing the disease and to further recurrence following transplantation-consequences of uremic state, alloimmunization and intercurrent infectious disease-are discussed.

Adult↗

[Comparative study of the University of Wisconsin solution versus Eurocollins in kidney transplant].

UW (University of Wisconsin) solution, formulated by Belzer's team in Madison, has already been proved to increase cold ischemia time in liver and pancreas preservation. A multicentre clinical trial is being conducted to compare renal preservation in human transplantation using two different solutions: UW and Eurocollins (EC). This paper, whose results will be included in the multicentre trial, reports local comparative results between UW and EC perfused Kidneys. The two donor populations UW (28 cases) and EC (47 cases) were not randomized. They were however comparable in renal function prior to harvesting but not in age (35 +/- 13.4 years EC versus 27.7 +/- 12.4 years UW). The two recipient populations (48 EC versus 48 UW) were more homogeneous. Comparative results were significant with better graft function in the UW group: creatinine at one week: 499.2 +/- 296.3 EC versus 277.6 +/- 226.2 mumol/l, p less than 0.0001; creatinine at one month: 228.7 +/- 135 EC versus 159.7 +/- 135.6 mumol/l, p less than 0.02 and a decrease in acute tubular necrosis (39.5% EC versus 14.5% UW) and hospital stay. These results justify the use of UW solution by intraaortic flush especially during multi-organ procurement.

Adenosine↗

[Lymphocele and kidney transplantation].

The authors report fourteen cases of lymphocele in a series of one thousand consecutive renal transplantations (1.4%). The prevention of these lymphoceles depends on rigorous lymphostasis. The diagnosis is based on ultrasonography. The treatment indicated in cases of voluminous lymphoceles consisted in marsupialization and omentoplasty.

Adult↗

Discrimination between CCK receptors of guinea-pig and rat brain by cyclic CCK8 analogues.

The properties of high affinity CCK8 binding sites of guinea-pig and rat brain cortex were compared using [3H]pCCK8. Large differences were observed, with the KD value being significantly higher in the rat (KD = 1.25 nM) than in guinea-pig brain (KD = 0.18 nM). Both sites exhibited different specificities for various CCK8 analogues, the selectivity factors KI rat/KI guinea-pig varied from 0.9 for CCK4 to 64 for cyclic CCK8-related compounds. Significant differences in the inhibition of [3H]pCCK8 binding by monovalent and nucleotides cations were also observed. These results could be explained by a difference in receptor environment or by a species difference in the proportion of CCK8 receptor-subtypes.

Animals↗

Mycotic aneurysm and renal transplantation.

A case of mycotic aneurysm secondary to suppuration of a renal transplant is reported. This aneurysm was responsible for ischemia of the leg and was treated successfully by ligation and venous bypass grafting.

Adult↗

Characterization of [3H] CCK4 binding sites in mouse and rat brain.

We have investigated the possible occurrence of distinct CCK8 and CCK4 binding sites in the brain by comparing the binding characteristics of [3H] CCK4 to those of the CCK8 analogue, [3H] Boc (Nle28,31]CCK27-33 (BDNL-CCK7). [3H] CCK4 and [3H] BNDL-CCK7 were shown to interact with mouse brain membranes with very similar maximal binding capacities 31.7 +/- 2.1 fmol/mg prot (KD = 3.78 +/- 0.47 nM) and 38.9 +/- 2.2 fmol/mg prot (KD = 0.26 +/- 0.02 nM) respectively. The apparent affinities of five CCK analogues for the sites labelled by both probes were almost identical. Autoradiographic studies revealed that the distribution of [3H] CCK4 binding sites in rat forebrain was the same as that of [3H] BDNL-CCK7, with high densities of receptors in the cortex, nucleus accumbens, olfactory bulb and the medial striatum, moderate densities in the amygdala, the hippocampus, several nuclei of the thalamus and hypothalamus. However in the interpenduncular nucleus where there was moderate binding of [3H]BDNL-CCK7, no [3H]CCK4 labelling was observed. These studies demonstrated the occurrence of one class of high affinity binding sites for [3H] CCK4 in mouse and rat brain, with characteristics similar to those already reported with CCK33, CCK8 and pentagastrin probes. Nevertheless the presence of a small amount of very high affinity binding sites for [3H]CCK4 cannot be excluded.

Animals↗

Membranous nephropathy in a bone marrow transplant recipient.

A bone marrow transplant recipient is described who had development of nephrotic syndrome in association with chronic graft-versus-host disease (GVHD) and on cyclosporine (CsA) treatment withdrawal. Renal biopsy revealed a membranous glomerulonephritis (MG). The possible relationship between this autoimmune disorder, the immunological features of GVHD in experimental animals, and the influence of CsA is discussed.

Adult↗

Cyclic cholecystokinin analogues with high selectivity for central receptors.

Taking as a model the N-terminal folding of the cholecystokinin tyrosine-sulfated octapeptide [CCK-8; Asp-Tyr(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2] deduced from conformational studies, two cyclic cholecystokinin (CCK) analogues were synthesized by conventional peptide synthesis: Boc-D-Asp-Tyr(SO3H)-Ahx-D-Lys-Trp-Ahx-Asp-Phe-NH2 [compound I (Ahx, 2-aminohexanoic acid)] and Boc-gamma-D-Glu-Tyr(SO3H)-Ahx-D-Lys-Trp-Ahx-Asp-Phe-NH2 (compound II). The binding characteristics of these peptides were investigated on brain cortex membranes and pancreatic acini of guinea pig. Compounds I and II were competitive inhibitors of [3H]Boc[Ahx28,31]CCK-(27-33) binding to central CCK receptors and showed a high degree of selectivity for these binding sites (compound I: Ki for pancreas/Ki for brain, 179; compound II: Ki for pancreas/Ki for brain, 1979). This high selectivity was associated with a high affinity for central CCK receptors (compound I: Ki, 5.1 nM; compound II: Ki, 0.49 nM). Similar affinities and selectivities were found when 125I Bolton-Hunter-labeled CCK-8 was used as a ligand. Moreover, these compounds were only weakly active in the stimulation of amylase release from guinea pig pancreatic acini (EC50 greater than 10,000 nM) and were unable to induce contractions in the guinea pig ileum (to 10(-6) M). The two cyclic CCK analogues, therefore, appear to be synthetic ligands exhibiting both high affinity and high selectivity for central CCK binding sites. These compounds could help clarify the respective role of central and peripheral receptors for various CCK-8-induced pharmacological effects.

Animals↗

Relationship between the liver and lymphocytotoxic alloantibodies in inbred rats. Specific absorption by nonparenchymal liver cells.

Liver allografts have a privileged status with regard to hyperacute rejection. In this experimental study, we have used extracorporeal liver hemoperfusion in sensitized rats in order to analyze reactions between lymphocytotoxic antibodies and the liver. In sensitized BN rats, a donor-specific (Lewis) extracorporeal liver hemoperfusion can delay hyperacute rejection of heart allografts and reduce the level of lymphocytotoxic antibodies. The decrease in the level of antibodies could be due to massive absorption of antibodies by the liver or to release of major histocompatibility complex antigens in a soluble form. Immunofluorescent examination of the hemoperfused liver revealed important deposits of C3 on Kupffer cells and of IgG on sinusoidal cells. On the contrary, in control rats in which a third-party (DA) liver hemoperfusion was performed, heart allograft survival was less prolonged, the decrease in the level of lymphocytotoxic antibodies was not significant, and the deposits of IgG and C3 were much less evident. The level of circulating immune complexes was unchanged after a donor-specific or a third-party liver hemoperfusion. These results support the hypothesis that resistance of the liver to hyperacute rejection might be due to a massive and nontoxic absorption of lymphocytotoxic antibodies on nonparenchymal liver cells.

Absorption↗

Delayed rejection of heart allografts after extracorporeal donor-specific liver hemoperfusion. Role of Kupffer cells.

Liver allografts have a privileged status in regard to acute rejection. In this experimental study, we have analyzed the immunosuppressive effects of an extracorporeal liver hemoperfusion. In the LEW-to-BN combination of inbred rats, donor-specific liver hemoperfusion can significantly delay acute rejection of heart allografts. Analysis of the immunological status of these animals revealed a significant decrease in donor-specific lymphocytotoxic antibodies and in cytotoxic T lympholysis. Reactivity in mixed lymphocyte culture was normal. After third-party (DA) liver hemoperfusion or after donor-specific (LEW) splenic hemoperfusion, prolongation of heart allograft survival was moderate. Previous blockade of Kupffer cells suppressed the effects of donor-specific liver hemoperfusion. These results suggest that the sequestration by Kupffer cells of a clone of cytotoxic T cells and/or lymphocytotoxic antibodies may explain the immunosuppressive effects of donor-specific liver hemoperfusion.

Animals↗