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S N Emancipator

Publications and source records attributed to S N Emancipator.

At least 19 recordsLinked to original sources
PubMed1998

Immunocytochemical colocalization of specific immunoglobulin A with sendai virus protein in infected polarized epithelium.

Immunoglobulin (Ig)A provides the initial immune barrier to viruses at mucosal surfaces. Specific IgA interrupts viral replication in polarized epithelium during receptor-mediated transport, probably by binding to newly synthesized viral proteins. Here, we demonstrate by immunoelectron microscopy that specific IgA monoclonal antibodies (mAbs) accumulate within Sendai virus-infected polarized cell monolayers and colocalize with the hemagglutinin- neuraminidase (HN) viral protein in a novel intracellular structure. Neither IgG specific for HN nor irrelevant IgA mAbs colocalize with viral protein. Treatment of cultures with viral-specific IgA but not with viral-specific IgG or irrelevant IgA decreases viral titers. These observations provide definitive ultrastructural evidence of a subcellular compartment in which specific IgA and viral envelope proteins interact, further strengthening our hypothesis of intracellular neutralization of virus by specific IgA antibodies. Our results have important implications for intracellular protein trafficking, viral replication, and viral vaccine development.

Animals↗
PubMed1998

Elevated neointimal endothelin-1 in transplantation-associated arteriosclerosis of renal allograft recipients.

BACKGROUND: Chronic renal allograft rejection is characterized histologically by transplantation-associated arteriosclerosis and glomerulosclerosis (Tx-AA and Tx-AGS). Recent studies in animal models implicate the mitogenic and pressor actions of endothelin-1 (ET-1) in Tx-AA. In humans, however, a link between elevated ET-1 secretion and Tx-AA or Tx-AGS remains unclear. In this study we analyzed expression of ET-1 in the vasculature of renal transplant patients with chronic or acute rejection and in normal controls. METHODS: Renal vascular and glomerular ET-1 was assessed by immunohistochemistry in 12 patients with clinically and histologically defined chronic rejection, in 11 patients with acute rejection, and in 5 normal kidneys. ET-1 staining was also correlated with various clinical parameters and with a morphometric index of neointima formation. ET-1 secretion was measured by ELISA in cultured human vascular cell types treated with T cell- and macrophage-associated cytokines. RESULTS: We found that renal allografts with chronic rejection and Tx-AA expressed 6.1-fold more ET-1 in the vasculature relative to allografts with acute rejection or to normal kidneys (P < 0.01). In Tx-AA, ET-1 was detected predominantly in the neointima, which contained mostly endothelial cells and smooth muscle cells. A strong positive correlation (r = 0.82, P < 0.01) was observed between vascular ET-1 peptide expression and hypertension in patients with chronic rejection. We also showed that macrophage-associated cytokines, but not T cell-associated cytokines, stimulated ET-1 secretion in human endothelial cells, vascular smooth muscle and mesangial cells. CONCLUSIONS: These results demonstrate that elevated ET-1 in the neointima is associated with Tx-AA and chronic rejection. In addition, these results point to an important role for endothelial dysfunction in chronic renal allograft rejection.

Adolescent↗
PubMed1998

Vascular and glomerular expression of endothelin-1 in normal human kidney.

To understand better the function of endothelin-1 (ET-1) in renal physiology, we examined vascular and glomerular expression of ET-1 in normal human kidney and in lupus nephritis. Immunohistochemical analysis revealed that renal endothelium of glomeruli, arteries, veins, and capillaries expressed ET-1. Endothelial cells were the principal source of glomerular ET-1; positive immunostaining was detected only rarely in mesangial cells and vascular smooth muscle cells from normal kidney. However, mesangial staining for ET-1 was elevated in patients with lupus nephritis, suggesting that under certain conditions mesangial cells elaborate ET-1. Indeed cultured human mesangial cells from normal subjects secreted ET-1 peptide. ET-1 secretion was augmented by the protein kinase C activator phorbol ester and by transforming growth factor-beta1 (TGF-beta1), a cytokine implicated in the development of glomerulosclerosis. Transient transfection of cultured mesangial cells with a preproET-1 reporter construct showed that the preproET-1 promoter is transcriptionally active in mesangial cells and is stimulated by TGF-beta1, phorbol ester, or ectopic expression of protein kinase beta1. Cultured human mesangial cells have both ETA and ETB receptors that contribute to ET-1-stimulated mitogenesis. Taken together, these results demonstrate that ET-1 is expressed at sites where paracrine or autocrine signaling by ET-1 might control renal vasoconstriction, glomerular filtration rate, and remodeling of the glomerulus in renal disease.

Cells, Cultured↗
PubMed1998

Frozen section biopsy assessment for the presence of polymorphonuclear leukocytes in patients undergoing revision of arthroplasties.

Despite progress in techniques, early or late deep infection develops in 1 to 5% of patients with prosthetic joint replacements. We report a retrospective review of 64 original frozen sections (FSs) compared with permanent sections, the preoperative clinical and intraoperative findings, and the subsequent culture results. A histologic section, frozen or permanent, was considered positive for infection if there were more than five polymorphonuclear leukocytes (PMNs) per high power field, excluding surface fibrin and inflammatory exudate, in at least five separate microscopic fields. The sensitivity of an FS as a diagnostic test to detect prosthetic infection when present was 43%. The specificity of an FS to correctly identify the absence of infection was 97%. These data support the conclusion that the FS is reasonably specific but not a sensitive diagnostic modality. If the preoperative evaluation is completely negative and the FS does not reveal PMNs, the reimplantation can be performed with minimal concern regarding the possibility of infection. If the preoperative and intraoperative evaluations are completely negative but PMNs are observed in the FS, then the surgeon should consider proceeding with caution; the decision to proceed with reimplantation might be delayed, depending on the surgeon's clinical assessment.

Arthroplasty, Replacement, Hip↗
PubMed1997

The glycosylation of IgA produced by murine B cells is altered by Th2 cytokines.

We sought to determine whether selected cytokines, known to profoundly increase proliferation and/or production of Ig by B cells and their progeny, also have as yet unrecognized effects upon IgA glycosylation. For these studies, we selected CH12LX mouse B lymphoma cells, a widely used model of B cell differentiation. Glycosylation was assessed by detection with enzyme-lectin conjugates in an immunoabsorption assay and verified by profiling and sequencing of the N-linked oligosaccharides. Stimulation of B cells with IL-4 plus IL-5 significantly alters the terminal glycosylation of secreted IgA, whereas LPS has a minor effect, despite the fact that both stimuli are equipotent at inducing Ig class switching and Ig secretion. Moreover, the alteration in terminal glycosylation was more profound on IgA secreted from surface IgM+ than from surface IgA+ CH12LX cells. These results suggest that the increased production of IL-4 and IL-5 by peripheral blood lymphocytes from IgA nephropathy patients might result in the production of abnormally glycosylated IgA. In turn, this abnormally glycosylated IgA may promote deposition of IgA in glomeruli in this disease.

Animals↗
PubMed1997

Processing of IgA aggregates in a rat model of chronic liver disease.

Heavy alcohol intake and/or lipotrope-deficient diet induced hepatocellular injury and mesangial deposition of IgA and often IgG in Lewis rats. The experimental animals showing more severe urinary abnormalities and histologic damage in the glomeruli had increased levels of IgA antibodies to dietary antigens and altered intestinal permeability. Based on human studies, the prolonged circulation of IgA-containing complexes associated with the liver disease could be envisaged as important for the development of mesangial IgA deposits. In order to verify this hypothesis, four groups (G) of Lewis rats were studied: G1 received thrice a weak an intragastric infusion of 1.5 ml/100 g body wt of whiskey; G2 rats were nourished with lipotrope-deficient diet; G3 rats were given both whiskey and LD diet; G4 rats were nourished with regular chow. After 12 weeks, heat-aggregated rat monomeric IgA was labeled with 133I and intravenously injected. Three control subgroups of rats, one given whiskey, one nourished with LD diet, and one with regular chow, were injected with radiolabeled heat-aggregated rat IgG. A large field-of-view digital gamma camera, equipped with an ultra-high-resolution collimator and interfaced to a dedicated computer, was used to analyze tracer kinetics and fate. The liver was the main organ involved in clearance of both test probes. The hepatic mean transit (MTT) was 11.4 +/- 11 min in G1 (proteinuria of 6.9 +/- 1.41 mg/day and hematuria +/+2), 221 +/- 19 min in G2 (proteinuria 9.1 +/- 0.64 mg/day and hematuria +2/+3), and 230 +/- 15 min in G3 (proteinuria 9.5 +/- 0.58 mg/day and hematuria +2/+3). In each case MTT value was found to be significantly prolonged compared to G4 (85 +/- 4 min). The multiple regression analysis showed that MTT values, proteinuria, and hematuria were significantly correlated (P < 0.01). Controls had trace amount proteinuria (0.82 +/- 0.17 mg/day, significantly lower than for each study group, P < 0.08) and undetectable hematuria. Similar results were obtained in control rats injected with aggregated IgG; i.e., MTT values were more prolonged in rats given whiskey or LD diet than normally nourished rats (P < 0.01). The lipotrope-deficient diet and the chronic alcohol abuse per se seem to lead to critical changes in hepatic uptake and catabolism of both an IgA and an IgG aggregate, which could account in turn for the reported appearance of renal immunoglobulin deposits in this experimental model. Due to the comparable delay in removal of IgA and IgG probes in equally nourished animals, additional factors are likely to be involved in the prominent deposition of IgA.

Animals↗
PubMed1997

Enhanced leukocyte binding by intestinal microvascular endothelial cells in inflammatory bowel disease.

BACKGROUND & AIMS: Microvascular endothelial cells mediate leukocyte homing, angiogenesis, and inflammation and healing and show tissue-specific adhesion molecules and functions. The activation of human intestinal mucosal microvascular endothelial cells (HIMECs) was studied in vitro to uncover possible abnormalities associated with inflammatory bowel disease. METHODS: HIMECs were isolated from normal and inflammatory bowel disease mucosa and assessed for phenotypic and morphological features, proliferative response, leukocyte binding capacity, and adhesion molecule expression. RESULTS: Basal proliferation by HIMECs was less than that of human umbilical vein endothelial cells (HUVECs) but increased proportionally more in response to vascular endothelial growth factor. Proinflammatory stimuli induced an activated, spindle-shaped morphology in HIMEC monolayers. Compared with HUVECs, unstimulated HIMECs showed less adhesiveness for U937 and MOLT4 cells and neutrophils, but cytokines and lipopolysaccharide substantially increased the binding capacity of HIMECs. HIMECs derived from inflammatory bowel disease mucosa showed a markedly greater leukocyte-binding capacity than normal mucosal HIMECs. Patterns of intercellular adhesion molecule 1, vascular cell adhesion molecule 1 and E-selectin messenger RNA expression were distinct in HIMECs, HUVECs, and mucosal mesenchymal cells. CONCLUSIONS: HIMECs represent differentiated endothelial cells with unique functional properties. Their dramatically enhanced capacity to bind leukocytes in inflammatory bowel disease suggests that HIMECs play an important role in initiating or maintaining inflammation.

Endothelium↗
PubMed1997

Histoplasmosis and kidney disease in patients with AIDS.

Renal disease in patients infected with human immunodeficiency virus (HIV) often presents with significant proteinuria and progressive renal failure; focal glomerulosclerosis is the most common renal pathology identified. To our knowledge, we report the first case of nephrotic-range proteinuria and preserved renal function in an HIV-infected patient in association with disseminated histoplasmosis. The initial level of proteinuria was 12.5 g/24 h. The patient developed a concomitant lesion on his neck, which was biopsied and identified as Histoplasma capsulatum by fungal stains and culture. The serum CF titer of antibody against yeast antigens of H. capsulatum was 1:8. The level of serum albumin decreased to 2.0 g/dL, and the level of serum cholesterol increased to 284 mg/dL. Immunohistochemical staining of renal biopsy tissue demonstrated immune complexes within the mesangium; H. capsulatum antigen was also demonstrated in the mesangium. Therapy with oral itraconazole resulted in marked clinical improvement. The findings in this case emphasize the need to rule out treatable causes of the nephrotic syndrome in AIDS, especially in cases of immune-complex glomerulonephritis.

AIDS-Related Opportunistic Infections↗
PubMed1997

Proinflammatory cytokines regulate Fc alphaR expression by human mesangial cells in vitro.

IgA nephropathy (IgAN) is defined by the predominant deposition of IgA immune complexes (IC) in the glomerular mesangium. Interaction between IgA immune complexes and mesangial cells (MC) could be a linchpin for the genesis of IgAN. We studied the modulation of MC expression of IgA receptors (Fc alphaR) by selected cytokines. Binding of 125I-IgA to quiescent human MC showed 2.55 x 10(5) sites/cell with an affinity (Ka) of 3.2 x 10(7) M(-1). Addition of selected recombinant cytokines had no significant influence on Ka, but increased the number of sites/cell relative to unstimulated cells. Northern hybridization using the pHuFc alphaR cDNA probe showed time-dependent increases in mRNA expression in stimulated versus control cells. IL-6 and tumour necrosis factor-alpha (TNF-alpha) had a biphasic effect on the Fc alphaR mRNA level; at 48 h, IL-6 increased steady state mRNA levels about six-fold relative to control, TNF-alpha increased mRNA four-fold, and interferon-gamma (IFN-gamma) induced Fc alphaR mRNA two-fold. By reverse transcriptase-polymerase chain reaction (RT-PCR), the Fc alphaR expressed on human MC appears highly homologous to that expressed by U937 cells. Altered Fc alphaR expression in response to cytokines may influence the pathogenesis of IgAN by affecting deposition and/or clearance of IgA-IC in the mesangium.

Animals↗
PubMed1996

Prednisone improves renal function and proteinuria in human immunodeficiency virus-associated nephropathy.

PURPOSE: To determine if prednisone ameliorates the course of human immunodeficiency virus-associated nephropathy (HIV-AN). PATIENTS AND METHODS: Twenty consecutive HIV-infected adults with biopsy-proven HIV-AN (n = 17) or clinical characteristics of HIV-AN (n = 3) with serum creatinine concentrations > 177 mumol/L (2 mg/dL) or proteinuria > 2.0 g/d or both were prospectively evaluated and treated with prednisone at a dose of 60 mg/d for 2 to 11 weeks, followed by a tapering course of prednisone over a 2- to 26-week period. Serum creatinine concentration, 24-hour protein excretion, serum albumin, and steroid-related adverse effects were assessed before and after treatment. RESULTS: Nineteen patients had serum creatinine concentrations > 117 mumol/L (2 mg/dL). Two of them progressed to end stage renal disease (ESRD) in 4 to 5 weeks. In 17 patients serum creatinine levels decreased from 717 +/- 103 mumol/L (8.1 +/- mg/dL) (mean +/- SE) to 262 +/- 31 mumol/L (3.0 +/- 0.4 mg/dL) (P < 0.001). Five patients relapsed after prednisone was discontinued and were retreated. In these 5 the serum creatinine declined from 728 +/- 107 mumol/L (8.2 +/- 1.2 mg/dL) to 344 +/- 47 mumol/L (3.9 +/- 0.5 mg/dL) (P < 0.01) in response to the second course of prednisone. Twelve of 13 tested patients showed a reduction in 24-hour urinary protein excretion with an average decrement from 9.1 +/- 1.8 g/d to 3.2 +/- 0.6 g/d (P < 0.005). Serum albumin increased from 24.4 +/- 3.6 g/L to 29.3 +/- 2.6 g/L (P = NS) in the 11 patients with paired 24-hour urine collections for whom pre- and post-treatment determinations were available. In one non-azotemic patient with nephrotic syndrome, protein excretion declined from 15.2 to 2.2 g/day and the serum albumin increased from 4.0 g/L to 31.0 g/L. The 20 patients have been followed for a median of 44 weeks (range 8 to 107). Eight ultimately required maintenance dialysis. Eleven died from complications of HIV disease 14 to 107 weeks after institution of prednisone; none was receiving prednisone at the time of death. Seven are alive and free from ESRD a median of 25 weeks (range 8 to 81) from the initiation of prednisone therapy. Six patients developed a total of seven serious infections while receiving prednisone, including Mycobacterium avium-complex infection in 2 and CMV retinitis in 3. CONCLUSION: Prednisone improves serum creatinine and proteinuria in a substantial proportion of adults with HIV-AN. Corticosteroid-related side effects are not prohibitive. A prospective, randomized controlled trial is required to confirm these preliminary results.

Adult↗
PubMed1996

Tubulointerstitial responses in the progression of glomerular diseases: albuminuria modulates alpha v beta 5 integrin.

Proteinuria represents one of the most unfavorable prognostic factors in the progression of nephropathies. Several lines of evidence support a role for proteinuria per se in the development of interstitial fibrosis, albeit the molecular mechanisms are still unknown. We investigated the potential role of integrins expressed on tubular cells in regulating the synthesis and organization of interstitial matrix or as mediators of tubulointerstitial damage in conditions mimicking the nephrotic milieu. Under basal conditions, cultured tubular cells highly expressed alpha 3 beta 1 and, at focal contacts, alpha v beta 3. In contrast, alpha v beta 5 was weakly and diffusely distributed all over the plasma membrane. Cultures on a variety of matrix substrates (fibronectin, laminin, collagen types I and IV, vitronectin, von Willebrand factor, fibrinogen) did not induce any phenotypic change in integrin expression by tubular cells. Conversely, the addition of albumin resulted in a highly increased membrane expression of beta 5, which was organized in typical focal contacts and was related to the dose of albumin added. Immunofluorescence, flow cytometry, immunoprecipitation and RT-PCR experiments argue for a complex mechanism that includes increased post-transcriptionally regulated protein synthesis, accelerated conversion of precursors to mature forms, and increased surface delivery to discrete adhesive structures. Up-regulation of the beta 5 chain in tubular cells was confirmed in 9 out of 11 kidney biopsies from proteinuric glomerulonephritides including membranous and focal sclerosing glomerulonephritis, while it was not expressed in nonproteinuric kidneys including five biopsy specimens. This is the first report indicating that proteinuria up-regulates the surface expression and distribution of a specific integrin chain on tubular cells. These observations suggest the participation of integrins in a hitherto unexplored mechanism of tubulo-interstitial responses to glomerular injury.

Albuminuria↗
PubMed1996

Interferon-inducible protein-10 is highly expressed in rats with experimental nephrosis.

Interferon-inducible protein (IP)-10 is a small glycoprotein member of a family of chemotactic cytokines structurally related to interleukin-8. We have recently described the induction of IP-10 mRNA in mouse mesangial cells stimulated with lipopolysacharide, interferon-gamma, and tumor necrosis factor-alpha. To further evaluate a possible role for this chemokine in renal injury, we have studied IP-10 in an experimental model of nephrosis induced in rats by adriamycin. High levels of glomerular IP-10 mRNA expression and glomerular and tubulointerstitial IP-10 protein were seen on day 21, coinciding with maximal proteinuria, glomerular tumor necrosis factor mRNA expression, and interstitial cellular infiltrates. Maintenance on a low protein diet not only delayed the appearance of proteinuria and interstitial cellular infiltrate but also decreased glomerular IP-10 mRNA expression. Isolated normal glomeruli and cultured glomerular epithelial and mesangial cells from normal rats expressed IP-10 mRNA upon stimulation with 100 U/ml interferon or 1 microgram/ml lipopolysaccharide for 3 hours. IP-10 mRNA expression was also inducible by lipopolysaccharide and cytokines in NRK 49F renal interstitial fibroblasts and, to a lesser extent, in NRK 52E tubular epithelial cells. Furthermore, IP-10 protein was inducible in murine mesangial cells. We conclude that IP-10 is highly inducible in vitro and in vivo in resident glomerular and tubulointerstitial cells. IP-10 may participate in the modulation of renal damage in experimental nephrosis.

Animals↗
PubMed1996

Hepatic pathology resulting from mouse hepatitis virus S infection in severe combined immunodeficiency mice.

Mouse hepatitis virus (MHV) is a pervasive pathogen that causes morbidity and mortality in mouse colonies worldwide. Although it is not a major cause of mortality in immunocompetent mice, infections from MHV strains of lower virulence can be fatal to athymic nude mice. The histopathologic features and alterations of serum biochemical parameters resulting from infection with a low-virulence MHV strain in severe combined immunodeficiency (scid) mice has not been well described. Thus we recently studied the disease caused by MHV-S in scid mice after intranasal inoculation. Mouse hepatitis virus infection in scid mice, which have severe defects of B and T cells, may be highly lethal, resulting in immediate mortality. However, our results indicate that scid mice survived for an average of 12 to 14 days after infection with doses of MHV up to 10(7) PFU/mouse. The virus caused a significant increase in serum enzyme activities and bilirubin concentration associated with histologically demonstrable hepatocellular injury at postinoculation days 3, 4, and 8. Furthermore, virus was detected in mouse liver homogenates and nasal and bronchial lavage specimens. These results provide valuable information regarding the histopathologic and biochemical consequences of MHV-S infection in scid mice.

Alanine Transaminase↗
PubMed1994

Hypocomplementemic urticarial vasculitis syndrome in identical twins.

Hypocomplementemic urticarial vasculitis syndrome (HUVS) is a syndrome of recurrent urticarial vasculitis, arthralgia/arthritis, and hypocomplementemia. Angioedema, ocular inflammation, glomerulonephritis, and obstructive lung disease are other clinical findings. Although the etiology of HUVS is unknown, its resemblance to systemic lupus erythematosus (SLE) suggests a similar pathogenesis. SLE is known to occur in identical twins. This is the first report of a pair of identical twins with HUVS. Concordance for HUVS in identical twins suggests that the pathogenesis of the disease involves abnormal genetic immunoregulation.

Adult↗
PubMed1994

Functional consequences of the binding of gliadin to cultured rat mesangial cells: bridging immunoglobulin A to cells and modulation of eicosanoid synthesis and altered cytokine production.

Oral immunization with gliadin (GLI) can induce immunoglobulin A mesangial deposits (IgA nephropathy [IgAN]) in mice. A role for GLI in human IgAN has been inferred from an association with celiac disease, increased serum anti-GLI IgA in patients with IgAN, and benefit from a gluten-free diet observed in some IgAN patients. These effects might be due to the antigenic or lectinic properties of GLI. The aim of our study was to investigate whether GLI binding to glycosylated residues (ie, lectinic activity) favors binding of GLI to cultured rat mesangial cells, bridging IgA macromolecules. We also sought to determine whether GLI binding alters mesangial cell function. Gliadin binds to rat mesangial cells in the third and fourth passages, as determined by immunofluorescence. Gliadin binding is inhibited by co-incubation with 1 mol/L N-acetyl-D-glucosamine and 1 mol/L alpha-D-mannose, sugars competitive for this lectinic bond. Quantification by biotinylated GLI revealed a significant dose-dependent binding of GLI (P < 0.001) inhibited by N-acetyl-D-glucosamine (P < 0.05). Some saccharolytic enzymes, like invertase, modify the cell surface to decrease GLI binding (P < 0.02). In addition, GLI promoted the binding of purified mouse polymeric IgA to mesangial cells. The binding of GLI to mesangial cells modulates arachidonic acid metabolism by cultured mesangial cells, significantly inhibiting prostaglandin E2 production (P < 0.02), increasing synthesis of thromboxane B2 (P < 0.01) and tumor necrosis factor (P < 0.001), but not interleukin-1 beta. These responses were abrogated by co-incubation with N-acetyl-D-glucosamine and/or pretreatment with invertase. Non-immune binding of an environmental alimentary lectin, GLI, to mesangial cells in culture might favor the binding of IgA and IgAIC to mesangial cells, enhancing both IgA mesangial trapping and in situ IgA deposit formation. This could occur via GLI-specific antibodies or by virtue of the binding of nonspecific IgA on a lectinic basis, or both. Moreover, related changes in eicosanoid synthesis might stimulate mesangial cell growth and mesangial matrix production, together with mesangial cell contraction, contributing to the pathogenesis of IgAN.

Animals↗