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L C Paul

Publications and source records attributed to L C Paul.

At least 37 records · Page 2Linked to original sources
PubMed2000

Long-term knowledge retention following predialysis psychoeducational intervention.

BACKGROUND/AIMS: Early identification and predialysis psychoeducation are gaining acceptance. Although research supports the immediate value of predialysis interventions, long-term benefits remain unknown. We examined long-term knowledge retention following a psychoeducational intervention. METHODS: 47 progressive renal failure patients completed the Kidney Disease Questionnaire at baseline and 18, 30, 42, and 54 months after initiating renal replacement therapy (RRT; the 'longitudinal' sample). A larger cohort provided data at one or more of these points (n = 132, 117, 101, and 70 at 18, 30, 42, and 54 months, respectively; the 'cross-sectional' sample). RESULTS: Initial knowledge gains among psychoeducation recipients were followed by a significant knowledge advantage for three groups throughout follow-up. Patients who received predialysis psychoeducation either before or after starting dialysis demonstrated superior Kidney Disease Questionnaire scores as compared with those identified before the initiation of RRT who received the usual standard of practice. Patients identified after the initiation of RRT and who received standard education, however, demonstrated the same level of knowledge retention as produced by psychoeducation. The results were identical across the longitudinal and cross-sectional samples. CONCLUSIONS: Patient education produces important benefits in end-stage renal disease, but the incremental value of early intervention remains to be demonstrated.

Adult↗
PubMed1999

Chronic allograft nephropathy: An update.

Chronic allograft nephropathy is the most prevalent cause of renal transplant failure in the first post-transplant decade, but its pathogenesis has remained elusive. Clinically, it is characterized by a slow but variable loss of function, often in combination with proteinuria and hypertension. The histopathology is also not specific, but transplant glomerulopathy and multilayering of the peritubular capillaries are highly characteristic. Several risk factors have been identified, such as advanced donor age, delayed graft function, repeated acute rejection episodes, vascular rejection episodes, and rejections that occur late after transplantation. A common feature of chronic allograft nephropathy is that it develops in grafts that have undergone previous damage, although the mechanism(s) responsible for the progressive fibrosis and tissue remodeling has not yet been defined. Hypotheses to explain chronic allograft nephropathy include the immunolymphatic theory, the cytokine excess theory, the loss of supporting architecture theory, and the premature senescence theory. The most effective option to prevent chronic allograft nephropathy is to avoid graft injury from both immune and nonimmune mechanisms.

Cellular Senescence↗
PubMed1999

Sharing cross-reactive groups of MHC class I improves long-term graft survival.

BACKGROUND: Renal transplant loss from chronic rejection remains substantial. To increase our understanding of this syndrome, we identified risk factors predicting late graft loss, with a special emphasis on the impact of human lymphocyte antigen (HLA) matching. METHODS: We studied all 654 cadaveric kidney transplants performed in our center between 1983 and 1996 that had survived for more than six months. Eighty-two transplants, lost because of chronic rejection, were used as the outcome variable. The influence of HLA mismatches and shares on long-term graft survival was evaluated at the level of private antigens and cross-reactive groups (CREG) of multiple histocompatibility complex (MHC) class I. HLA and other recipient, donors and transplant parameters were studied using univariate and multivariate Cox regression analysis. RESULTS: The cohort had a mean number of 1.9 HLA mismatches. Because of the homozygosity of HLA antigens, HLA mismatches were not reciprocal to shares. CREG and HLA-A-B mismatches had a relative risk for graft loss of 1.19 (95% CI, 0.97 to 1.45) and 1.05 (0.84 to 1.32) per mismatch. In contrast, the relative risk per shared CREG and broad HLA-A-B antigen was 0.76 (0.63 to 0.92) and 0.79 (0.61 to 1.03). Multivariate analysis revealed that individuals sharing less than four CREGs had a relative risk of 2.13 (1.29 to 3.75) for late graft loss. Other independent predictors were a recipient age of less than 50 years, relative risk 1.95 (1.02 to 3.71); a donor age of more than 50 years, relative risk 1.68 (1.01 to 2.80); acute rejection (vascular vs. no rejection), relative risk 3.52 (1.72 to 7.18); proteinuria (dipstick > 1+ vs. negative), relative risk 2.86 (1.29 to 6.35); and a serum creatinine concentration of more than 150 micromol/liter at six months, relative risk 3.41 (1.96 to 5.94). CONCLUSION: We identified several coexisting recipient-, donor-, and transplant-related risk factors for graft loss from chronic rejection. In this well-matched group of renal transplants, HLA mismatches and shares had a nonreciprocal relationship. Sharing of HLA antigens, especially CREG of MHC class I, was associated with improved long-term survival.

Adult↗
PubMed1998

Eotaxin and capping protein in experimental vasculopathy.

Ischemia-induced tissue activation may contribute to the pathogenesis of graft vasculopathy, but the mediators implicated have only partially been characterized. To gain further insight into the molecular mechanisms involved, syngeneic rat aortic transplants with cold-storage-induced vasculopathy were studied for differentially expressed mRNA transcripts. Vessel segments were exposed to either 1 or 18 hours of cold ischemia, followed by transplantation into syngeneic recipients. After 3 days or 4 weeks, the grafts were removed and total mRNA was isolated and used for differential display to identify modulation of transcript expression related to prolonged storage. Using 15 sets of random primers, 17 polymerase chain reaction products were up-regulated and 2 were downregulated in grafts exposed to 18 hours of ischemia. Sequencing of these amplicons showed that 6 had a high degree of homology to known sequences whereas 13 had no homology to any of the genes in the database. Two of the differentially displayed amplicons (capping protein and eotaxin) were cloned, re-amplified, and used as probes for Northern blot analysis to confirm their differential expression. Immunohistochemistry using monoclonal antibodies against capping protein-alpha and eotaxin confirmed that both proteins are expressed in the media of normal aortas and that there was an increased expression in vessels exposed to prolonged ischemia albeit that the increase at the protein level seemed less compared with changes in transcript expression. Northern blots with RNA from aortic allografts exposed to prolonged ischemic storage also showed increased levels of capping protein and eotaxin mRNA whereas there was a decrease in the relative amount of these transcripts in vessels exposed to balloon denudation, suggesting that the increase after prolonged ischemic exposure is not the result of a nonspecific response to injury. Based on the biological characteristics of capping protein and eotaxin it is conceivable that they play a pathogenetic role in ischemia-induced vessel wall remodeling. It remains to be established whether these genes or their products serve as target molecules for therapeutic interventions to prevent or treat cold-storage-induced graft vasculopathy.

Actin Depolymerizing Factors↗
PubMed1998

Effect of misoprostol on myocardial contractility in rats treated with cyclosporin A.

The nephrotoxic side effects of the immunosuppressant cyclosporin A in animals and humans are well known. Misoprostol, a prostaglandin E analog, is used clinically in organ-transplant recipients taking cyclosporin A to protect against these side effects. We reported previously that long-term treatment of rats with cyclosporin A causes a diminution in myocardial peak contractile stress. There is an associated spontaneous sarcomere activity and rest depression of force in the absence of a change in myofilaments sensitivity to intracellular Ca2+. Here we investigated the potential protective effects of misoprostol on the myocardium of cyclosporin A-treated rats. Rats were treated with either cyclosporin A, misoprostol, or their combination. Force-[Ca2+]o and -[Sr2+]o, and force-interval relations as well as the sarcomere length were studied in trabeculae isolated from the right ventricles. At suboptimal [Ca2+]o, cyclosporin A shifted the force-[Ca2+]o relation to the left but reduced peak contractile stress by approximately 35% at the highest (optimal) [Ca2+]o. Co-treatment with misoprostol prevented the leftward shift, and treatment with misoprostol alone did not cause a leftward shift. The diminution of peak stress, however, did not recover with misoprostol treatment, and stress was further reduced. Treatment with only misoprostol also reduced stress generated by the muscles more than that by cyclosporin A alone. Intriguingly, activation of the myofilaments by Sr2+ failed to recover peak stress to control levels in any group treated with misoprostol. Unlike cyclosporin A, however, rest potentiation of force was more pronounced, and spontaneous sarcomere activity was absent with misoprostol. No histopathologic changes were observed with cyclosporin A or misoprostol treatment. Misoprostol modifies the cyclosporin A-induced changes in the Ca2+ handling, but further decreases the stress generated by the muscles.

Animals↗
PubMed1998

Antibodies against mesangial cells and their secretory products in chronic renal allograft rejection in the rat.

Antibodies or cell-mediated immunity can cause chronic rejection of vascularized organ grafts, but the nature and specificity of the antigen(s) involved has remained elusive. We have previously demonstrated the presence of antibodies against cryptic glomerular basement membrane antigens and undefined antigens in the mesangial area in rats with chronic renal allograft rejection. Current experiments were designed to study the post-transplant antibody response against cultured mesangial and endothelial cells in rats with chronic rejection using flow cytometry, indirect immunofluorescent staining, immunoelectron microscopy, confocal microscopy, and Western blots. The results were compared with those obtained with alloantisera raised by immunization with cultured mesangial cells. Post-transplant and post-immunization sera contained IgG antibodies against trypsinized mesangial cells detected by flow cytometry. Indirect immunofluorescent studies using mesangial cells grown on coverslips showed autoantibody binding to cytoplasmic granules in cultures early after plating whereas staining of later cultures showed antibody binding in an interrupted, web-like pattern on the outside of the cells. Immunoelectron microscopy showed autoantibody binding to intracellular secretory granules and to cell surface focal adhesion plaques. The latter finding was confirmed in double-labeling experiments with an antiserum against vinculin. Western blots with mesangial cell culture supernatants demonstrated autoantibody reactivity with antigens in the 40-kd and 60- to 70-kd range, and immunoprecipitation identified these molecules as biglycan and decorin. Absorption of the sera with mesangial cell culture supernatant removed most of the antibodies except those that gave a punctate staining with the mesangial cell surface. However, not all immunostaining of mesangial cells could be explained by antibodies against biglycan and decorin. Post-transplant sera, furthermore, contained low-titered antibodies against endothelial cells. We conclude that rats with chronic renal transplant rejection produce a strong autoantibody response against mesangial cell focal adhesion plaques and proteins secreted by these cells in culture. Such antibodies may cause local damage and interfere in the tissue repair process after injury.

Animals↗
PubMed1998

Control of monocyte influx in glomerulonephritis in transplanted kidneys in the rat.

Induction of anti-Thy-1 nephritis in different strains of inbred rats results in phenotypically different types of renal diseases. In Wistar and Lewis (LEW) rats, a transient influx of ED1+ macrophages occurs 24 hours after injection of anti-Thy-1 antibodies, whereas this does not occur in F344 rats. The present experiments were designed to investigate the role of the kidney in the regulation of the monocyte influx in this model. To dissociate the role of the immune system from local intrarenal factors in the control of monocyte influx, anti-Thy-1 nephritis was induced in LEW rats with an F344 kidney transplant and in F344 rats with a LEW kidney allograft. Acute rejection episodes were prevented by treatment with an anti-CD4 monoclonal antibody. Control rats received a syngeneic kidney graft. Monocyte influx after injection of anti-Thy-1 antibodies was found in the glomeruli of both LEW and F344 kidneys removed from LEW recipients, whereas there was no demonstrable monocyte influx after infusion of anti-Thy-1 antibodies in either LEW or F344 kidneys removed from F344 recipients. Monocyte infiltration correlated with the subsequent expansion of the mesangial extracellular matrix. The inability to attract monocytes was not due to the lack of glomerular expression of chemokines, because F344 and LEW glomeruli demonstrated a similar expression of monocyte chemoattractant protein-1 (MCP-1). Differences in the ability to activate the complement system were excluded. We conclude that the immune system controls the glomerular influx of monocytes and that the reaction of the mesangial cells is probably controlled by combinations of cytokines produced during the inflammatory process.

Animals↗