PubMed Health⌕ Search

Biomedical subjects

K L Gordon

Publications and source records attributed to K L Gordon.

24 records · Page 2Linked to original sources
PubMed1996

Changes in cell-cycle protein expression during experimental mesangial proliferative glomerulonephritis.

A characteristic response to mesangial cell injury is proliferation, which is closely linked to mesangial matrix accumulation and the progression of glomerular disease. Cell proliferation in non-renal cells in vitro is regulated at the level of the cell-cycle by specific cyclins and their catalytic partners, cyclin dependent kinases (CDK). Cyclin kinase inhibitors (CKI) prevent proliferation by inhibiting cell-cycle progression. However, the expression of cell-cycle regulatory proteins in the kidney and in renal disease is unknown. To determine this we studied the expression of cell-cycle proteins in vivo in normal rats and rats with experimental mesangial proliferative glomerulonephritis (Thy1 model). Normal quiescent rat glomeruli have a differential expression for CKI's, where p27Kip1 is highly expressed, and the levels for p21 (Cip1, Waf1, Sdi1, Cap20) (p21) are low. The onset of mesangial cell proliferation in Thy1 glomerulonephritis is associated with a reduction in p27Kip1 levels when mesangial cell proliferation is maximal. Mesangial cell proliferation in vivo is also associated with an increase in glomerular expression of cyclin A, and an increase in expression and activity for CDK2. The resolution of mesangial cell proliferation was associated with a return to baseline levels for p27Kip1, while the expression for p21 increased substantially. Furthermore, mesangial cell p21 expression was maintained following the resolution of proliferation. These results provide evidence for a complex interplay of cell-cycle regulatory proteins during the glomerular response to injury in vivo. The marked increase in CDK2 expression during mesangial cell proliferation and the sustained increase in p21 expression following the resolution of mesangial cell proliferation suggests that the in vivo expression of certain cell-cycle proteins may differ from that described in non-renal cells in vitro.

Animals↗
PubMed1996

Beneficial effects of systemic immunoglobulin in experimental membranous nephropathy.

To test the hypothesis that systemic administration of immunoglobulin might reduce glomerular injury in membranous nephropathy through mechanisms involving inhibition of complement activation, we studied the passive Heymann nephritis (PHN) model of membranous nephropathy in rats. The daily administration of immunoglobulin goat IgG (600 mg/kg i.p.) reduced proteinuria by 52%. Quantitative immunohistochemical analysis showed that the glomerular deposition of C3c, an indicator of ongoing complement attack, and of C5b-9 was significantly decreased in the immunoglobulin treated group, while deposition of anti-Fx1A was not affected. Electron microscopic analysis demonstrated that the extent of subepithelial immune complexes did not appreciably differ between treated and control animals. Systemic complement levels were not altered by immunoglobulin treatment. These data suggest that the reduction in proteinuria that resulted from systemic immunoglobulin administration was mediated by modifying the effect of complement induced glomerular injury. This interpretation was further supported by in vitro data that documented a significant reduction in C5b-9 induced glomerular epithelial cell lysis in the presence of both goat and rat IgG. These results indicate that systemic administration of immunoglobulin can substantially reduce ongoing complement activation in the glomerulus in PHN rats and that this effect is associated with a significant reduction in glomerular injury.

Animals↗
PubMed1996

SPARC is expressed by mesangial cells in experimental mesangial proliferative nephritis and inhibits platelet-derived-growth-factor-medicated mesangial cell proliferation in vitro.

Mesangial cell proliferation is a characteristic feature of many glomerular diseases and often precedes extracellular matrix expansion and glomerulosclerosis. This study provides the first evidence that SPARC (secreted protein acidic and rich in cysteine) could be an endogenous factor mediating resolution of experimental mesangial proliferative nephritis in the rat. SPARC is a platelet-derived-growth-factor-binding glycoprotein that inhibits proliferation of endothelial cells and fibroblasts. We now show that SPARC is synthesized by mesangial cells in culture and that SPARC mRNA levels are increased by platelet-derived growth factor and basic fibroblast growth factor. Recombinant SPARC or the synthetic SPARC peptide 2.1 inhibited platelet-derived-growth-factor-induced mesangial cell DNA synthesis in vitro. In a model of experimental mesangioproliferative glomerulonephritis, SPARC mRNA was increased 5-fold by day 7 and was identified in the mesangium by in situ hybridization. Similarly, SPARC was increased in glomerular mesangial cells and visceral epithelial cells by day 5 and reached maximal expression levels by day 7. Mesangial cell proliferation increased by 36-fold on day 5 and decreased abruptly on day 7. Maximal expression of SPARC was correlated with the resolution of mesangial cell proliferation. We propose that SPARC functions in part as an endogenous inhibitor of platelet-derived-growth-factor-mediated mesangial cell proliferation in glomerulonephritis and that it could account for the resolution of cellular proliferation in this disease.

Amino Acid Sequence↗
PubMed1995

IL-1 beta increases laminin B2 chain mRNA levels and activates NF-kappa B in rat glomerular epithelial cells.

The amount and distribution of laminin in the glomerular basement membrane (GBM) change in the course of many types of glomerular disease. Because interleukin-1 (IL-1) is thought to play a role in the pathogenesis of glomerulonephritis, it raises the possibility that this and other cytokines might regulate laminin gene expression. To determine whether laminin B2 chain mRNA levels change in response to cytokines, total mRNA from rat glomerular epithelial cells (GEC) grown in culture was analyzed by Northern blots. These studies showed an increase in laminin B2 chain mRNA levels in GEC treated with IL-1 beta. Nuclear factor kappa B (NF-kappa B) is a cytokine-responsive factor that regulates transcription of many genes from the cognate kappa B enhancer element. The mouse laminin B2 chain promoter contains several kappa B-like motifs, suggesting that NF-kappa B might be involved in IL-1-induced laminin B2 chain gene expression. Nuclear extracts from IL-1 beta-treated GEC showed increased binding to the immunoglobulin kappa B enhancer element and to a kappa B consensus sequence from the murine laminin B2 chain promoter in an electrophoretic mobility-shift assay (EMSA). The immunoglobulin kappa B and the laminin B2 chain kappa B-like motifs competed for the same DNA binding activity in nuclear extracts from IL-1 beta-treated GEC. Pretreatment of these nuclear extracts with antibodies to either the p50 or p65 subunits of NF-kappa B abrogated the DNA binding activity recognized by either of the two DNA motifs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Recovery of neuromuscular function after infusion or intermittent bolus doses of atracurium or vecuronium.

Neuromuscular block and postoperative recovery of grip strength and peak expiratory flow (PEF) were compared in patients receiving atracurium or vecuronium administered by continuous infusion or intermittent bolus doses. The same total dose of atracurium (0.92-0.98 mg kg-1) or vecuronium (0.16-0.18 mg kg-1) was given by both methods. A similar degree of neuromuscular block was attained in all groups. A control group receiving no neuromuscular blocking drugs was also studied. Grip strength and PEF were reduced significantly in all groups (less than 80% of preoperative value) 15 min after operation. This was most marked following infusion of vecuronium (less than 50%). Grip strength recovered in all groups in 30-60 min. PEF was still significantly less than control value at 90 min in all groups receiving neuromuscular blocking drugs.

Adult↗