Characterization of C-type natriuretic peptide receptors in human mesangial cells. Our aim was to examine whether the human glomerulus was a target for C-type natriuretic peptide (CNP) and how A, B ...and C receptors of natriuretic peptides (ANPR-A, ANPR-B, ANPR-C) were distributed in glomerular mesangial and epithelial cells. CNP stimulated cyclic GMP production in cultured human mesangial and epithelial cells with similar threshold concentrations (1 nM) and maximum effects (basal value × 30 at 1 µM). In contrast, atrial natriuretic peptide (ANP) was only stimulatory in epithelial cells. 125I CNP bound specifically to mesangial cells with a Kd of 0.47 nM and Bmax of 42 fmol/mg. Equilibrium of binding was obtained after four to five hours at +4°C and nonspecific binding represented 10 to 20% of total binding. HS142-1 (100 µg/ml), a specific inhibitor of ANPR-A and ANPR-B, suppressed 90% of CNP-dependent cyclic GMP production whereas it had little effect on 125I-CNP binding, suggesting that C receptors were largely predominant in mesangial cells. No biological effect of CNP on mesangial cells, including change in basal or angiotensin II-induced contractility and inhibition of basal or serum-dependent proliferation, could be demonstrated. Similar results were obtained with 8-bromo-cyclic GMP and sodium nitroprusside. Intraglomerular localization of ANPR-A, ANPR-B and ANPR-C mRNA was studied using reverse transcriptase-polymerase chain reaction with amplification of their corresponding cDNA by different primers. Amplification products were identified on gel electrophoresis by their predicted sizes and sequencing. ANPR-A, ANPR-B and ANPR-C mRNA were present in epithelial cells whereas only ANPR-B and ANPR-C mRNA were detected in mesangial cells. The presence of ANPR-C in both cell types was confirmed by Northern blot analysis. This study indicates that human mesangial cells, in contrast with epithelial cells, are not a target for ANP whereas both cell types respond to CNP and possess clearance receptors.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
RATIONALE AND OBJECTIVESThe authors investigate the relative sensitivity of rat mesangial cells to iodinated contrast media (CM) and control solutions versus less differentiated cells(ie, human ...fibroblasts) and compare the effects of low-osmolar ionic (ioxaglate) and nonionic (iopamidol) and high-osmolar ionic (diatrizoate) CM on rat mesangial cells.
METHODSThe cytotoxic effects of ioxaglate and control solutions of sodium chloride and mannitol were assessed by neutral red uptake in isolated rat mesangial cells and human fibroblasts. In a second series of studies, the cytotoxic effects of ioxaglate, iopamidol, and diatrizoate (0 to 100 mg I/mL) on rat mesangial cells were compared.
RESULTSRat mesangial cells were more sensitive to the cytotoxic effects of ioxaglate than the less differentiated human fibroblasts between 70 and 100 mg I/mL. A similar discrepancy was observed in the case of control solutions, sodium chloride, and mannitol. Ioxaglate and iopamidol induced a similar level of cytotoxicity in rat mesangial cells whereas the high-osmolar agent diatrizoate was significantly more cytotoxic. However, the calculated inhibitory concentrations of 50% of all three CM were associated with similar osmolalities, suggesting a major role for this parameter in the case of such media.
CONCLUSIONSRat mesangial cells are more sensitive to the cytotoxic effects of CM and hyperosmolar solutions than the less differentiated human fibroblasts. High-osmolar CM are more cytotoxic than ionic and nonionic low-osmolar CM to rat mesangial cells. Ionicity seems to play no deleterious role at similar iodine concentrations because ioxaglate and iopamidol had equivalent cytotoxic effects on mesangial cells.
Cyclosporin A (CsA)-induced nephrotoxicity is churucterized by a decrease in the glomerular filtration rate (GFR) which is associated with a large increase in renal vascular resistance (RVR). Using a ...video image analyzer, we have demonstrated CsA-induced glomerular vasoconstriction in rat isolated glomeruli as assessed by a significant reduction of glomerular area. This vasoactive response explains in part the renal hemodynamic changes and the development of CsA-induced reversible decline in renal function. To confirm the direct vasoactive effect of CsA on glomeruli and to rietermine if calciumblocking agents modified this response, we compared the changes in area of isolated rat and human glomeruli incubated either with CsA alone or with CsA plus verapamil. The area of the isolated glomeruli was quantitatively evaluated by a camera video image analyzer; euch glomerulus served as its own control. Area kinetics were studied at 5 min intervals oves 30 min. CsA-induced glomerular size reduction is dose dcpendent (-4.2% for 10-10 M crnd -10.2% for 10−6 M) and time dependent (-2.3% at 5 min, -4.7% at 10 min, and -12.1% at 30 min for 10−6 M). With verapamil pretreatment, CsA-induced reduction in glomerular size was reduced (-0.6% and -3.6%, respectively, for 10−6 M and 10−7 M verapamil). Thus, verapamil can be considered as a protective agent against CsA-induced vasoconstriction in rat and human isolated glomeruli.
Gliosarcome El Malki, M.; Lakhdar, A.; Badre, L. ...
Neuro-chirurgie,
9/2005, Volume:
51, Issue:
3
Journal Article
Peer reviewed
Le gliosarcome représente 2 % des glioblastomes. Nous rapportons une observation clinique d’un malade de 65 ans, présentant un aspect similaire à un méningiome. À travers cette observation, nous ...discuterons les particularités diagnostiques, thérapeutiques et pronostiques de cette entité.
Gliosarcomas account for 2% of glioblastomas. We report a case of gliosarcoma in a 65-year-old man, which presented as meningioma, and discuss diagnostic, therapeutic and prognostic aspects of this particular entity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
5.
Gliosarcomas. A case report El Malki, M; Lakhdar, A; Badre, L ...
Neuro-chirurgie
51, Issue:
3-4 Pt 1
Journal Article
Peer reviewed
Gliosarcomas account for 2% of glioblastomas. We report a case of gliosarcoma in a 65-year-old man, which presented as meningioma, and discuss diagnostic, therapeutic and prognostic aspects of this ...particular entity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
6.
Gliosarcomas. A case report El Malki, M; Lakhdar, A; Badre, L ...
Neuro-chirurgie,
09/2005, Volume:
51, Issue:
3-4 Pt 1
Journal Article
Peer reviewed
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
7.
Gliosarcome : À propos d'un cas EL MALKI, M; LAKHDAR, A; IRAQI, M. A ...
Neuro-chirurgie,
2005, Volume:
51, Issue:
3-4
Journal Article
Peer reviewed
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Specific cutaneous manifestations of sarcoidosis can be extremely varied. We report one observation of cutaneous sarcoidosis with an exceptional clinical presentation: icthyosiform erythroderma.
A ...33-year-old woman had a dry icthyosiform erythroderma associated with arthralgia and muscular deficit of the pelvic belt in a context of fever and weight loss. Skin biopsy revealed the presence of an epithelioid giant-cell granuloma. This granuloma was also found in the salivary glands and in the bronchial mucosa. The chest X ray showed diffuse reticularis opacities. The diagnosis of sarcoidosis was retained. The patient was treated with oral prednisone (0.75 mg/kg/day). Total skin clearing was obtained after 15 days.
This observation points out the heterogeneous nature of clinical manifestations of cutaneous sarcoidosis. The icthyosis erythroderma form is exceptional. Correct diagnosis is difficult and must be based on clinical, histological, radiological and biological criteria of sarcoidosis.
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