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Biomedical subjects

E G Neilson

Publications and source records attributed to E G Neilson.

142 records · Page 8Linked to original sources
PubMed1984

Mapping of the genes for tubular basement membrane antigen and a submaxillary gland protease in the rat.

The gene for tubular basement membrane (Tbm) antigen in the rat has been mapped relative to other markers in the first linkage group, and a polymorphic locus for a submaxillary gland protease, Tamase-1, has been identified. The hair-loss mutation fuzzy has also been mapped and occupies a position which is similar to that of the frizzy gene in the mouse. There are now at least five, and possibly six, genetic loci distributed over more than 30 centimorgans in the first linkage group of the rat which map in positions of approximate homology on the seventh chromosome of the mouse.

Alleles↗
PubMed1984

Analysis of peritoneal macrophages in continuous ambulatory peritoneal dialysis patients.

Peritoneal macrophages (PMC) from patients undergoing continuous ambulatory peritoneal dialysis (CAPD) were compared to peritoneal macrophages from healthy volunteers and to peripheral blood monocytes (PBM) from CAPD patients, hemodialysis patients, and healthy volunteers. PMC from CAPD patients had morphology similar to PMC and PBM from healthy volunteers. HLA-DR antigen and Fc receptors were present on the cell surface. These monocytes had similar sequential morphologic changes in long-term culture compared to PBM from healthy volunteers. Phagocytosis, hydrogen peroxide generation and bactericidal activity were the same in PMC from CAPD patients as in PBM from healthy volunteers. Chemotaxis and eicosanoid precursor uptake studies suggest that PMC from CAPD patients may be relatively immature bone-marrow-derived cells. Although these cells function well as phagocytes, further study is warranted to define their immune competence, many components of which develop during differentiation into mature macrophages and may therefore be deficient in patients undergoing CAPD.

Adolescent↗
PubMed1984

Murine interstitial nephritis. II. The adoptive transfer of disease with immune T lymphocytes produces a phenotypically complex interstitial lesion.

The present studies demonstrate that immune Thy-1.2+, Lyt-1.2+ T lymphocytes harvested from SJL mice with anti-tubular basement membrane disease can adoptively transfer interstitial nephritis into naive recipients. The lesions produced after cell transfer do not occur immediately but rather take 4 to 6 wk to fully develop. Interstitial lesions can also be transferred to a lesser degree and over a longer period of time with immune serum containing anti-tubular basement membrane antibodies. The fully formed lesions that developed after the transfer of immune cells or serum were phenotypically characterized by cell-surface antibodies using immunofluorescence. T lymphocytes, natural killer cells, macrophages, and Ig+ cells were all well represented in both lesions. Natural killer cells, however, were slightly more prevalent in the lesions of mice receiving immune serum. These experiments demonstrate a potential role for both immune T lymphocytes and anti-tubular basement membrane antibodies in the development of interstitial nephritis in mice. Unlike guinea pigs and rats, it is only in mice that interstitial lesions can be adoptively transferred with immune T lymphocytes, and as such, this model should prove very useful in the additional dissection of cellular interactions and immunoregulatory events that formulate the final effector mechanisms of disease expression.

Animals↗
PubMed1984

Spontaneous interstitial nephritis in kdkd mice. I. An experimental model of autoimmune renal disease.

Mice of the kdkd strain predictably develop a spontaneous tubulointerstitial nephritis after 8 wk of life. In this report we have examined several aspects of the nephritogenic immune response that seemed potentially relevant to the expression of this progressively destructive renal lesion. Of particular interest is that by direct immunofluorescence we were unable to demonstrate the presence of antibodies to determinants in the tubulointerstitium. Serum and kidney eluates from nephritic mice, furthermore, did not stain any renal structures in normal kidney. We did observe, however, that disease could be transferred through kdkd----CBA/Ca bone marrow chimeras, and prevented, in the reverse direction, by CBA/Ca----kdkd chimeras. The development of the interstitial lesion was markedly inhibited by thymectomy with T cell depletion, but disease could not be adoptively transferred with cells or serum from nephritic mice. The interstitial lesions also did not appear in (kdkd X CBA/Ca)F1 hybrids, and the development of disease in kdkd mice could be inhibited by treatment with adoptively transferred T cells from CBA/Ca mice. With these new findings we now hypothesize that susceptibility to the expression of interstitial nephritis in kdkd mice involves the cellular limb of the immune system, and may be related, in part, to alterations in regulatory T cell function.

Animals↗
PubMed1983

Polymorphism of genes involved in anti-tubular basement membrane disease in rats.

Inbred strains of rats differ widely in their susceptibility to interstitial nephritis induced by rabbit renal tubular basement membrane (TBM) preparations. We now report that susceptibility is determined in part by an RT1-linked gene for effector cell responsiveness producing interstitial lesions. Furthermore, we also obtained evidence that the gene determining expression of the target TBM antigen is linked to the gene for albinism on the first linkage group. When non-susceptible rats lacking the TBM antigen but having the gene for cellular responsiveness were mated with non-susceptible rats which had the TBM antigen but lacked the gene for cellular responsiveness, the F1 hybrids were susceptible to the induction of interstitial nephritis. Although strains varied widely in the amount of anti-TBM antibody (alpha TBM-Ab) they produced, this variation does not appear to be controlled by RT1-linked genes, nor does the isotype or amount of antibody appear to be related to the susceptibility to infiltrating cellular lesions.

Albinism↗
PubMed1982

Murine interstitial nephritis. I. Analysis of disease susceptibility and its relationship of pleiomorphic gene products defining both immune-response genes and a restrictive requirement for cytotoxic T cells at H-2K.

Anti-tubular basement membrance (alpha TBM) disease-producing interstitial nephritis in mice is not dependent on the generation of alpha TBM antibodies. Susceptibility seems to be defined by very private specificities in H-2K. These specificities are pleiomorphic, providing both immune-response genes and identity restrictions for cytotoxic effector functions expressed by a Thy-1.2+, Lyt-2,3+ T cell. These studies establish a role for T cells in the pathogenesis in interstitial nephritis as well as providing further evidence for the role of H-2K in the expression of an autoimmune disease.

Animals↗
PubMed1982

Suppression of interstitial nephritis by auto-anti-idiotypic immunity.

Rats immunized with renal tubular antigens were protected from the development of interstitial nephritis by pretreatment with tubular antigen-reactive T lymphoblasts. Protected animals developed anti-idiotypic antibodies against idiotypes primarily within the antigen-binding region of monoclonal antitubular basement membrane antibodies. These studies extend the concept of auto-anti-idiotypic regulation to autoimmune disease, and they also provide an experimental basis for further efforts to develop biologically relevant mechanisms for attenuating the expression of other kidney diseases.

Animals↗
PubMed1980

Cell-mediated immunity in interstitial nephritis. III. T lymphocyte-mediated fibroblast proliferation and collagen synthesis: an immune mechanism for renal fibrogenesis.

Fibroblast proliferation and collagen synthesis play an important role in the progression of intersititial nephritis. To evaluate the involvement of immune mechanisms in this process, we induced intersititial nephritis in guinea pigs utilizing injections of tubular antigens. Over a 3-week period, injected animals developed a nephritis characterized by mononuclear infiltrates and expanding areas of fibrotic scar formation. Involved kidneys contained increased collagen as compared to controls. To identify mediators of the observed fibrogenesis, T lymphocytes from nephritic and control animals were stimulated with soluble tubular antigens. Dialyzed supernatants from control lymphocyte cultures contained an inhibitor of both fibroblast proliferation and collagen synthesis. In contrast, supernatants from nephritic animals demonstrated absence of inhibition and a progressively increasing titer of a factor that enhanced both kidney fibroblast proliferation and collagen synthesis. As the disease progressed, however, nephritic lymphocytes also began secreting an inhibitor of proliferation that could be detected in low levels. These studies suggest, therefore, that immune mechanisms and altered lymphocyte function may play an important role in the development, progression, and regulation of renal fibrogenesis in intersititial nephritis.

Animals↗
PubMed1979

Cell-mediated immunity in interstitial nephritis. II. T lymphocyte effector mechanisms in nephritic guinea pigs: analysis of the renotropic migration and cytotoxic response.

The present studies investigate the effector role of lymphocytes in guinea pigs with an interstitial nephritis. Several observations were made relative to a number of functions expressed by these cells. The results of adoptive cell migration studies suggest that a subpopulation of T cells in nephritic animals traffic renotropically to either normal or damaged kidneys on transfer. Similar lymphocytes were also tested in vitro for direct effector function by utilizing target kidney cell monolayers in a cell-mediated cytotoxicity assay. The kinetics of the observed cytotoxic response were studied over the life span of nephritic animals. Optimal target-cell lysis occurred 12 to 17 days after sensitization, simultaneous with the onset of active histopathologic changes. The cytotoxicity was stoichiometrically titratable and relatively specific for fetal kidney tissue. In addition, cells from the spleen or lymph nodes of diseased animals effectively suppressed this cytotoxic response. These findings demonstrate that a diverse population of T lymphocytes are both capable of damaging the renal interstitium as well as modulating effector-cell functions on a regional basis with the immune system.

Animals↗
PubMedDate not supplied

Role of protein kinase C and cyclic AMP/protein kinase A in high glucose-stimulated transcriptional activation of collagen alpha 1 (IV) in glomerular mesangial cells.

The elevated mRNA levels encoding matrix components in glomeruli isolated from streptozotocin-induced diabetic rats provide evidence that stimulation of matrix synthesis is important in early phases of diabetic glomerulopathy. We and others have demonstrated that high glucose stimulates collagen mRNA levels in short-term mesangial cell culture. To test whether transcriptional activation is operative and to gain insights into the underlying mechanisms, we studied a murine mesangial cell line stably transfected with a minigene expressing luciferase driven by 5'-flanking and first-intron regions of the alpha 1(IV) gene. High glucose stimulated luciferase activity dose and time dependently, with optimal stimulation (two-fold) achieved after 48 h in 450 mg/dL glucose (G450) versus 100 mg/dL (G100). We next tested the involvement of protein kinase C (PKC) because high glucose has been shown to stimulate de novo synthesis of diacylglycerol (DAG). Increasing PKC activity by treatment with a DAG analogue or active phorbol ester stimulated luciferase activity preferentially in G100; addition of the PKC inhibitors staurosporine or calphostin C markedly inhibited luciferase activity preferentially in G450. Thus high glucose promotes transcriptional activity of alpha 1(IV) gene through PKC activation. We also tested the involvement of protein kinase A (PKA). Intracellular cyclic AMP levels were increased two fold after 48 h in G450 versus G100, and addition of 8-Br-cAMP (0.1 mM) preferentially stimulated luciferase activity by almost three fold in G100 versus only 1.2-fold in G450. Hence, the signal-transduction mechanisms underlying the transcriptional activation of alpha 1(IV) gene in mesangial cells by high glucose are mediated by pathways involving the PKC system and possibly the cAMP/PKA system.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMedDate not supplied

Angiotensin II induces alpha3(IV) collagen expression in cultured murine proximal tubular cells.

Angiotensin II (ANG II) induces cellular hypertrophy of cultured proximal tubular cells from various species. This hypertrophic response is associated with an increase in synthesis of basement membrane-associated collagen type IV. Previous investigations by our group have shown that ANG II stimulates mRNA and protein expression of the "classic" alpha1 and alpha2(IV) chains in cultured murine proximal tubular cells (murine cortical tubules [MCT cells]). Since it is clearer today that kidney basement membranes also contain heterotrimers of novel type IV collagens, the aim of the present study was to evaluate whether ANG II may influence the expression of alpha3 and alpha5(IV) collagen chains in MCT cells. A single dose of 10-8-10-6 M ANG II stimulated mRNA expression of alpha3(IV), but not of alpha5(IV), in MCT cells cultured in serum-free media. This response was mediated through AT1-receptors because losartan, but not an AT2-receptor antagonist, abolished the ANG II-induced expression of alpha3(IV) transcripts. Transient transfection of MCT cells with transforming growth factor-beta1 (TGF-beta1) antisense phosphorothioate-modified oligonucleotides partly abolished the ANG II-induced alpha3(IV) mRNA expression. Furthermore, Western blots of cellular lysates incubated with polyclonal antibodies generated against the recombinant collagen chains revealed that ANG II stimulated alpha3(IV) but not alpha5(IV) protein expression. This stimulation was partly prevented by co-incubation with a neutralizing anti-TGF-beta1-3 antibody. In summary, our data indicate that ANG II stimulates expression of the alpha3(IV) collagen chain in cultured MCT cells, due in part to TGF-beta1 activation.

Angiotensin II↗