Allozyme variation of oleaster populations (wild olive tree) (Olea europaea L.) in the Mediterranean Basin.

As a result of the early domestication and extensive cultivation of the olive tree throughout the Mediterranean Basin, the wild-looking forms of olive (oleasters) presently observed constitute a complex, potentially ranging from wild to feral forms. Allozyme variation was analysed at 10 loci in 31 large and 44 small oleaster populations distributed in various habitats of the Mediterranean Basin and in two populations of the wild subspecies Olea europaea subsp (ssp) guanchica, endemic to the Canary islands and closely related to oleasters. At eight polymorphic loci, 25 alleles were identified. Genetic evidence that nondomesticated oleasters still survive locally was provided by the occurrence of four and one alleles shared exclusively by the eight western and two eastern oleaster populations, respectively, which were collected in forests potentially containing genuinely wild forms according to environmental, historical and demographic criteria. As reported previously from cytoplasmic and RAPDs analysis, substantial genetic differentiation was observed between the eastern oleaster populations genetically close to most olive clones cultivated in the Mediterranean Basin, and the western populations that are related to the wild Canarian populations. In addition, the occurrence of significantly lower heterozygosity in cultivated olive than in oleasters, whatever their origin, suggests that intensive selection involving inbreeding has taken place under cultivation to obtain particular characteristics in the olive cultivars.

Antibody-induced modulation of the leukocyte CD11b integrin prevents mild but not major renal ischaemic injury.

BACKGROUND: CD11/CD18 beta(2) integrins are involved in leukocyte adhesion to the activated endothelium, and therefore represent a possible therapeutic target in the prevention of ischaemic acute renal failure (ARF). METHODS: To assess the effect of an anti-CD11b monoclonal antibody (mAb) in ischaemic ARF, uninephrectomized Fischer rats were subjected to 45 or 60 min of warm renal ischaemia, then received 1 mg of anti-CD11b mAb 5 min before reperfusion. RESULTS: After 45 min of ischaemia, renal function tests at 24 and 48 h were less altered in mAb-treated than in control rats, but after 60 min of ischaemia the same level of renal insufficiency was observed in the two groups. In parallel, milder tubular necrosis and less leukocyte infiltration were observed in the treated group after 45 min of ischaemia, but no difference was seen after 60 min compared to the control group. The mAb was detected on blood neutrophils up to 48 h after infusion and a marked down-regulation of CD11b expression on neutrophil surfaces was documented by flow cytometry. CONCLUSION: These results indicate that anti-CD11b mAb administered prior to reperfusion decreases moderate ischaemic ARF but fails to prevent renal injury secondary to prolonged ischaemia in this model.

In vivo effects of monoclonal antibodies against rat beta(2) integrins on kidney ischemia-reperfusion injury.

BACKGROUND: Ischemia-reperfusion (IR) involves adhesion of leukocytes to the activated endothelium, leading to tissue damage. CD11/CD18 beta(2) integrins interact with their ligands on endothelial cells and may therefore represent a therapeutic target for the prevention of IR. We investigated the effects of three monoclonal antibodies (mAbs) that recognize epitopes of heavy or light chain of the beta(2) integrins on IR in kidneys. METHODS: Uninephrectomized Fischer rats were subjected to 45 or 60 min of renal ischemia, treated with intravenously anti-beta(2) integrin monoclonal antibodies (anti-CD11a, anti-CD11b, and anti-CD18) 5 min prior to reperfusion, and compared to a nontreated group. Serum creatinine, blood urea nitrogen (BUN), and kidney histopathological damages were assessed at 1, 2, and 7 days after ischemia. RESULTS: After 45 and 60 min of ischemia, serum creatinine and BUN were significantly higher in the control than in animals treated with anti-CD11a and anti-CD18 at 24 and 48 h. Administration of anti-CD11b had a beneficial effect on renal function after 45 min but not after 60 min of ischemia. Histologic and immunostaining studies demonstrated mild tubular necrosis and less leukocyte infiltration in the anti-CD11a- and anti-CD18-treated groups compared to the control group. CONCLUSION: These results indicate that selected antibodies to CD11a/CD18 may decrease kidney IR injury when administered prior to reperfusion.

Interleukin-10 in Epstein-Barr virus-associated post-transplant lymphomas.

We used enzyme-linked immunosorbent assays (ELISA) to investigate the presence of interleukin-10 (IL-10) in the serum of patients developing post-transplant lymphomas. Serum IL-10 was detected in 14 out of 19 cases with a lymphoma or Hodgkin's disease, with higher values being observed in patients who had developed a lymphoma within the first few months post-transplantation, and who had an aggressive form of the disease. Eleven out of the 14 patients in whom IL-10 was detected had Epstein Barr virus-positive tumors. And 11 out of 14 patients died of lymphomas. In most of the patients who had detectable IL-10 at the time of diagnosis of the lymphoma, the IL-10 had not been present previously, but it was found in the serum of 7 out of 9 dialysis patients, and in 8 out of 17 stable transplant patients. We conclude that IL-10 plays a role in the development of the more severe forms of post-transplant lymphomas, and may be secreted by tumor cells. However. data from patients with chronic renal failure or patients undergoing immunosuppressive therapy must be treated with caution.

Human fetal liver cells induce colonies in spleen of lethally irradiated mice.

Murine hematopoietic tissues contain cells which, upon injection into lethally irradiated mice, produce nodules on the surface of their spleen (colony-forming unit--spleen; CFU-S). The exact hierarchical level of the hematopoietic progenitors which give rise to CFU-S is not fully established; however, cell populations highly enriched for repopulating stem cells appear to contain a high percentage of CFU-S. The experiments reported here involved the injection of human fetal liver cells into mice, under conditions similar to those of the CFU-S test. These data demonstrate that human fetal liver cells are able to induce spleen colonies (tentatively called human CFU-S) when injected into lethally irradiated mice. The number of CFU-S was increased by prior purification of human fetal liver cells. When mice were injected with human fetal liver cells inactivated by irradiation, no human CFU-S were observed. Positive staining of cells found in spleen colonies, using monoclonal antibodies specific for various human determinants, indicated the human origin of part of them. The presence of human cells within the colonies was further confirmed by in situ hybridization using a probe specific for human DNA. A mean of 30-40% of analyzed colonies was thus shown to contain some patches of human cells. These data confirm that human hematopoietic cells are able to seed, proliferate, and differentiate in a murine microenvironment.

Antihypertensive effect of thymectomy in Lyon hypertensive rats. Vascular reactivity, renal histology, and sodium excretion.

The aim of this study was to search for the possible mechanisms involved in the antihypertensive effect of neonatal thymectomy that we previously observed in Lyon hypertensive (LH) rats. To that end, we studied in LH and normotensive control (LN) rats the consequences of neonatal thymectomy on vascular reactivity, renal structure, and pressure-natriuresis. The increase in pressor responses to angiotensin I and phenylephrine noted in LH rats as compared to LN animals was abolished by neonatal thymectomy. Histological study showed that kidneys from LH rats exhibited arterial wall hypertrophy, segmental hyalinization of the glomeruli, and were infiltrated by mononuclear cells. All these features of kidney injury were reduced in neonatally thymectomized LH rats. Lastly, the responses of isolated perfused kidneys from LH rats to stepwise reductions in renal perfusion pressure differed from those of LN rats by decreased renal perfusion flow and natriuresis. Neonatal thymectomy tended to improve sodium excretion in parallel with a slight decrease in renal vascular resistances. It is concluded that the normalization of vascular responsiveness to vasoconstrictor factors, the alleviation of renal lesions and, to a lesser extent, the moderate improvement of pressure natriuresis may account, at least in part, for the antihypertensive effect of neonatal thymectomy in LH rats.

Image analysis of dendritic cells in the human fetal thymus.

The distribution and evolution of thymic dendritic cells (DC) were studied during human ontogeny. Immunochemical techniques were used to detect S100 protein-positive cells on fetal thymus sections, at different post-fecundation (PF) ages; an image analysis of these positive cells was then carried out. Variations in the percentage of these cells in the medulla were determined according to age: the higher percentages were seen at 12 and 16 weeks PF. Dendritic cells were present at an early stage in the thymic rudiment (7 weeks PF), a finding consistent with an origin of these cells in the fetal liver, and with the possible existence of local attraction and/or maturation factors. The expression of the CD54 adhesion molecule revealed the existence of particular interactions between DC and lymphocytes in the medullary area, and at the cortico-medullar junction. Diffuse CD11a (LFA-1) expression on lymphocytes was consistent throughout gestation. The monocyte/macrophage markers (CD11b, CD14) and the reaction of non-specific esterases showed that the distribution pattern of these cells differed from the DC pattern. These ontogenic data are related to the significant role played by DC throughout the different stages of thymopoiesis.

Cyclosporine A nephrotoxicity: evidence for mesangial foam-cells in dogs.

Nephrotoxicity of cyclosporine A was studied in dog after 3 weeks' administration of the drug at high doses (20 mg/kg/day). Cyclosporine A concentrations measured in different organs revealed a high ratio between renal tissue and plasma. Renal histopathology showed non-specific tubular lesions and glomerular modifications. There were lipids in the mesangial cells which took on a foamy aspect. Ultrastructural study and lipid staining confirmed these findings, and non-specific esterase reaction revealed no macrophagic infiltration. Using anti-CSA antibodies it was not possible to demonstrate CSA in the mesangial cells. This alteration has never been described before in CSA therapy and its meaning is not clear; however, it does suggest that there occur modifications in the lipid metabolism or in the phagocytic function of the mesangial cells when cyclosporine A is administered over long periods.

[Macrophage infiltration in human glomerulonephritis: histochemical study by the non-specific esterase method]. / Infiltration macrophagique au cours des glomérulonéphrites humaines: etude histochimique par la méthode de l'activité des estérases non spécifiques.

Detection of glomerular macrophages in glomerulonephritis (GN) was attempted in 77 renal biopsies by measuring non-specific esterase (NSE) activity. Macrophage infiltration was at its highest in two cases of cryoglobulinemia (NSE index greater than 10) both associated with a diffuse proliferative GN. In 15 cases of lupus, macrophage infiltration was low or absent (NSE index 0.44). In diffuse proliferative GN (24 cases) only GN with extracapillary proliferation had an NSE index greater than 1. In GN with predominant IgA (23 cases), apart 2 cases of extracapillary forms, there was no notable macrophage infiltration. There is a relation between monocytes and the localization and the quantity of glomerular deposits. The NSE index is higher in the case of large sub-endothelial deposits of immunoglobulins, C3 and/or fibrin.

[Inversion of the right hemi-diaphragm associated with abundant pleural effusion (author's transl)]. / Inversion diaphragmatique droite lors des épanchements pleuraux abondants. Etude échotomographique.

The radiological appearance and the physiopathological consequences of the phenomenon of the inversion of the diaphragm on the left side associated with abundant pleural effusion, were studied by Felson and his school as early as 1965. Echotomography reveals that the phenomenon occurs on the right side in exactly the same way.