Biomedical subjects

E Rondeau

Publications and source records attributed to E Rondeau.

150 records · Page 9Linked to original sources

PubMed1983

Reactive oxygen production by cultured rat glomerular mesangial cells during phagocytosis is associated with stimulation of lipoxygenase activity.

To investigate the phagocytic capability of glomerular mesangial cells and the biochemical events associated with phagocytosis, rat cultured mesangial cells were incubated in the presence of opsonized zymosan (STZ) and production of reactive-oxygen species and lipoxygenase products were determined. Mesangial cells were identified on the basis of morphologic (presence of microfilaments and pattern of staining by an anti-myosin antiserum) and physiologic (contractile activity in response to angiotensin II) characteristics. No contamination by esterase-positive cells was observed. Electron microscopy revealed that the phagocytic process started after 5 min of incubation, and affected approximately 50% of the cells. Superoxide anion (.O2-) and hydrogen peroxide (H2O2) generation by mesangial cells exposed to STZ increased with time and STZ concentration. Cells incubated with zymosan particles treated with heated serum produced undetectable amounts of .O2- and 6 times less H2O2 than cells exposed to STZ. Pretreatment by cytochalasin B produced a marked decrease in STZ-stimulated production of reactive oxygen species. [3H]Arachidonic acid was incorporated into mesangial cell phospholipids and its release and conversion into monohydroxyeicosatetraenoic acids (HETE) was measured by radiometric high performance liquid chromatography (HPLC). Incubation with STZ markedly stimulated the release of arachidonic acid from its phospholipid stores and its transformation into 11-, 12-, and 15-HETE. Lipoxygenase inhibitors inhibited STZ-stimulated H2O2 production, whereas they did not modify the phagocytic process as shown by the absence of any effect on the uptake of 125I-STZ by the mesangial cells. This study demonstrates that a high percentage of rat cultured mesangial cells phagocytose opsonized particles. The phagocytic process results in an oxidative burst that appears to be dependent on stimulation of the lipoxygenase pathway.

Animals↗

PubMed1983

Immune disorders in agnogenic myeloid metaplasia: relations to myelofibrosis.

Tests for a dysimmune state were done in an unselected group of 67 patients with agnogenic myeloid metaplasia (AMM). The results were compared to those of 56 patients with polycythaemia vera (PV). 75% of AMM patients versus 32% of PV patients had various abnormalities. The most frequent disorders among AMM patients were serum antinuclear and anti smooth muscle autoantibodies (10.3% each), a positive test for rheumatoid factor (21.7%), a polyclonal increase in serum immunoglobulin levels (46.8%) or a serum monoclonal component (9.7%), a positive direct Coombs' test (19%), an anti I autoantibody (30%). In AMM patients there was no relationship between age, sex, importance of splenic enlargement, time from diagnosis or treatment and the present of a dysimmunity. Furthermore, in AMM patients, but also in PV patients, it seems that the more frequent and numerous these abnormalities the more severe is the myelofibrosis. Like other previous studies, these results suggest a lymphoid cell involvement in AMM and a role for these immune disorders in the pathogenesis of myelofibrosis.

Adult↗

PubMed1982

High plasma antidiuretic hormone in patients with cardiac failure: influence of age.

Plasma antidiuretic hormone (ADH) was greater in patients with cardiac failure than in healthy subjects. Plasma ADH increased significantly with age in both groups. Covariance analysis showed that the difference between patients and controls occurred whatever the age. Plasma sodium and plasma osmolality were lower in cardiac patients than in healthy subjects. This showed that increase in plasma ADH observed in patients was inappropriate since it coexisted with inhibitory levels of plasma osmolality. Plasma creatinine was greater in cardiac patients than in healthy subjects and for each group in elderly than in young people. But there was no significant correlation between plasma ADH and creatinine. This suggested that increase in plasma ADH observed in cardiac failure was due more to an augmented release than to a diminished catabolism. No clear influence of etiology, severity, length of the disease and treatment with diuretics could be demonstrated.

Adolescent↗

PubMedDate not supplied

[A case of alcohol-induced ketoacidosis?].

We report a case of severe ketoacidosis. Initially the patient showed metabolic acidosis, the anion gap was positive and there was neither hyperlactatemia nor intoxication with acid substances. As the rate of glycemia was high (17.8 mmol/L), the diagnosis of diabetic ketoacidosis was proposed. Under treatment with continuous IV injection of insulin, hypoglycemia (1.8 mmol/L) appeared rapidly, while urine bioreactive test was positive for ketonuria, but negative for glycosuria. We finally concluded that it was an alcoholic ketoacidosis. The history of the patient confirmed the diagnosis : chronic alcoholism with recent increased of alcohol intake which provoked vomiting and fasting. This case report shows the difficulty in distinguishing between alcoholic ketoacidosis and diabetic ketoacidosis. We discuss the diagnostic strategy and particularly biologic data in the light of pathophysiologic mechanism of alcoholic ketoacidosis.

Alcoholism↗

PubMedDate not supplied

Induction of MHC class II molecules HLA-DR, -DP and -DQ and ICAM 1 in human podocytes by gamma-interferon.

MHC class II-encoded molecules HLA-DR, -DP and -DQ play a pivotal role in the human immune response. Their constitutive expression is restricted to a number of immunocompetent cells referred to as antigen-presenting cells. However, gamma-interferon (gamma-IFN) has been shown to induce MHC class II molecule expression in several epithelia. Using flow cytometric analysis, we show here that normal and SV40-transformed human podocytes in culture constitutively expressed gamma-IFN receptors. We also show that MHC class I molecules are constitutively expressed in these cells and that HLA-DR, -DP and -DQ expression, which is not found in unstimulated cells, can be induced by gamma-IFN stimulation. This induction was a time-dependent event, a lag phase of 24-48 h being necessary for MHC class II molecules to become detectable at the cell surface by flow cytometric analysis. Induction of MHC class II molecules in human podocytes also showed a concentration dependence, a plateau being reached at a concentration of 500 IU of gamma-IFN/ml of culture medium. This effect was blunted by coincubation of the cells with an antihuman gamma-IFN receptor monoclonal antibody. HLA-DR expression was associated with specific mRNA accumulation, as detected by Northern blot analysis. By indirect immunofluorescence, the intercellular adhesion molecule 1 was also induced by gamma-IFN stimulation. Induction of DR, DP and DQ in human podocytes may be involved in the pathogenesis of immune glomerulonephritis in man.

Blotting, Northern↗

PubMedDate not supplied

Relationship between alpha-smooth muscle actin expression and fibrotic changes in human kidney.

The alpha-smooth muscle (alpha-SM) actin isoform is expressed normally by vascular SM cells and by stromal fibroblastic cells in pathological conditions leading to fibrosis. In order to investigate the relation between kidney fibrosis and alpha-SM actin expression, we studied 51 renal biopsies from 45 patients: 30 with various forms of glomerulonephritis; 1 with acute tubular necrosis; 1 with acute interstitial nephritis, and 13 renal transplant recipients. The presence of alpha-SM actin was examined by using anti-alpha SM-1, a mouse monoclonal antibody (IgG2 alpha) specific for alpha-SM actin. alpha-SM actin scores were estimated semiquantitatively, as were glomerulosclerosis and interstitial fibrosis. In acute tubular necrosis and in well-functioning grafts, alpha-SM actin expression was limited to vascular SM cells. In glomerular diseases, alpha-SM actin expression was upregulated in mesangial area in 25 of 36 biopsies, and even more frequently in the periglomerular and peritubular interstitium (34 of 36 cases, chi 2 = 7.6, P < 0.01). Whereas glomerular alpha-SM actin expression seemed to decrease as glomerulosclerosis progressed, there was a positive correlation between interstitial alpha-SM actin scores and the degree of interstitial fibrosis. Similarly, interstitial alpha-SM actin expression was found in acutely or chronically rejected kidneys, but not in well-functioning grafts. We conclude that upregulation of alpha-SM actin in the glomerulus indicates mesangial cell activation and is not always correlated with the degree of glomerulosclerosis. In contrast, interstitial upregulation of alpha-SM actin which indicates myofibroblast activation is correlated with the degree of interstitial fibrosis.

Actins↗