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Biomedical subjects

A Breborowicz

Publications and source records attributed to A Breborowicz.

At least 37 records · Page 2Linked to original sources
PubMed2001

Comparison of the biocompatibility of phosphate-buffered saline alone, phosphate-buffered saline supplemented with glucose, and dianeal 3.86%.

OBJECTIVE: We compared the effects of intraperitoneal infusion of phosphate-buffered saline (PBS, pH 7.4), of PBS supplemented with 3.86% glucose (G), and of standard dialysis solution [Dianeal 3.86%: Baxter Healthcare Corporation, Deerfield, IL, U.S.A. (D)] on intraperitoneal inflammation in dialyzed rats. METHODS: After catheter implantation, rats were infused on day 1 with PBS, on day 3 with PBS+G, on day 5 with D, and on day 7 again with PBS (PBS-2). After a 4-hour dwell, dialysate samples were collected and analyzed. RESULTS: All dialysate parameters studied [dialysate cell count, neutrophil:macrophage ratio (Ne:Ma), and total protein], except tumor necrosis factor alpha (TNFalpha), were comparable during both PBS infusions. During dialysis with PBS+G, the inflammatory response was suppressed as compared with the first dialysis with PBS (cell count, p < 0.001; Ne:Ma, p < 0.05; TNFalpha, p < 0.001; total protein, p < 0.001). During dialysis with D, peritoneal inflammatory parameters were further suppressed (cell count, p < 0.001 vs PBS and p < 0.01 vs PBS+G; Ne:Ma, p < 0.001 vs PBS and p < 0.05 vs PBS+G; TNFalpha, p < 0.001 vs PBS and p < 0.001 vs PBS+G; total protein, p < 0.001 vs PBS and p < 0.01 vs PBS+G). CONCLUSIONS: Hypertonicity of the dialysis fluid suppresses intraperitoneal inflammatory parameters in rats. The suppression was even more severe when Dianeal 3.86% was used. That finding could be due to the low pH and presence of GDPs in the fluid.

Animals↗
PubMed2001

Replacement of glucose with N-acetylglucosamine in peritoneal dialysis fluid-experimental study in rats.

BACKGROUND: Glucose is still used as an osmotic solute in peritoneal dialysis fluids, despite evidence of its local (peritoneal) and systemic toxicities. However a constant search is underway for a new, more biocompatible osmotic solute for peritoneal dialysis fluids. OBJECTIVE: The present study evaluated N-acetylglucosamine (NAG) in a concentration of 220 mmol/L as an alternative to glucose for the osmotic solute in peritoneal dialysis fluid, during chronic peritoneal dialysis in rats. METHODS: For 8 weeks, male Wistar rats were infused with glucose-based or NAG-based dialysis fluid. Intraperitoneal inflammation and peritoneal permeability and morphology were evaluated in all rats during the study. RESULTS: Repeated intraperitoneal infusion of the NAG-based dialysis fluid resulted in a weaker intra-abdominal inflammatory reaction as compared with the reaction in rats infused with glucose-based dialysis solution. At the end of the study, the concentration of hyaluronan in the peritoneal interstitium obtained from NAG-treated rats was higher than that found in the interstitium taken from animals exposed to dialysis fluid containing glucose. Also, peritoneal permeability to total protein was lower in NAG-treated rats. CONCLUSION: As an alternative to glucose, NAG used for the osmotic solute in peritoneal dialysis solution decreases the intraperitoneal inflammatory reaction induced by the process of peritoneal dialysis and, indirectly (owing to the increased hyaluronan content in the peritoneal interstitium), diminishes peritoneal permeability to protein.

Acetylglucosamine↗
PubMed2000

IL-17 stimulates intraperitoneal neutrophil infiltration through the release of GRO alpha chemokine from mesothelial cells.

IL-17 is a newly discovered cytokine implicated in the regulation of hemopoiesis and inflammation. Because IL-17 production is restricted to activated T lymphocytes, the effects exerted by IL-17 may help one to understand the contribution of T cells to the inflammatory response. We investigated the role of IL-17 in leukocyte recruitment into the peritoneal cavity. Leukocyte infiltration in vivo was assessed in BALB/Cj mice. Effects of IL-17 on chemokine generation in vitro were examined in human peritoneal mesothelial cells (HPMC). Administration of IL-17 i.p. resulted in a selective recruitment of neutrophils into the peritoneum and increased levels of KC chemokine (murine homologue of human growth-related oncogene alpha (GROalpha). Pretreatment with anti-KC Ab significantly reduced the IL-17-driven neutrophil accumulation. Primary cultures of HPMC expressed IL-17 receptor mRNA. Exposure of HPMC to IL-17 led to a dose- and time-dependent induction of GROalpha mRNA and protein. Combination of IL-17 together with TNF-alpha resulted in an increased stability of GROalpha mRNA and synergistic release of GROalpha protein. Anti-IL-17 Ab blocked the effects of IL-17 in vitro and in vivo. IL-17 is capable of selectively recruiting neutrophils into the peritoneal cavity via the release of neutrophil-specific chemokines from the peritoneal mesothelium.

Animals↗
PubMed2000

Dialysis solution containing hyaluronan: effect on peritoneal permeability and inflammation in rats.

BACKGROUND: Hyaluronan (HA), a high molecular weight mucopolysaccharide found in interstitial tissues and fluid, is lost from the peritoneal cavity during peritoneal dialysis. In order to determine the role of HA in peritoneal function, we investigated the effects of exogenous HA on peritoneal permeability, markers of intraperitoneal inflammation, and peritoneal morphology in rats exposed to peritoneal dialysis solution for four weeks. METHODS: Wistar rats were infused intraperitoneally, twice daily, with conventional, hypertonic dialysis solution (Dianeal 3.86%; control) or Dianeal solution containing 10 mg/dL of high molecular weight HA. Peritoneal permeabilities and clearances of solutes and protein were determined using a modified peritoneal permeability test (peritoneal equilibration test) at the beginning and the end of the treatment. Peritoneal volume and ultrafiltration were determined using a macromolecular marker and by gravimetric methods. Peritoneal inflammation was determined by cell counts and differential and by the measurement of cytokine concentrations in the dialysate effluent. Peritoneal thickness and HA content were determined in liver and mesentery biopsies taken at the end of the experiment. RESULTS: After four weeks of exposure to the dialysis solution, transperitoneal protein equilibration was significantly lower in HA-treated rats compared with rats treated with Dianeal alone (46% lower for albumin, P < 0.003; 33% lower for total protein, P < 0.001). The total drained volume after a four hour dwell was 29% higher in the HA group compared with the control (P < 0.001), yielding a positive net ultrafiltration in the HA group versus a negative net ultrafiltration in controls. Peritoneal clearances of urea and creatinine tended to be elevated in HA-treated rats, while clearances of total protein and albumin tended to be lower. Dialysate effluent from rats exposed to HA contained a lower percentage of neutrophils (8.8 +/- 22.8 +/- 9.5%, P < 0.01) and lower levels of the cytokines, tumor necrosis factor-alpha (11.2 +/- 14.7 vs. 42.3 +/- 35.3 pg/mL, P < 0.05) and monocyte chemoattractant protein-1 MCP-1 (72.0 +/- 86.5 vs. 402.4 +/- 258.3 pg/mL, P < 0.02), compared with rats treated with Dianeal alone. The thickness of the peritoneal interstitium showed a similar increase in both groups, but mesenteric tissue from the HA group contained more HA (48%, P < 0.01) than tissue from control animals. CONCLUSIONS: The addition of HA to peritoneal dialysis solution decreases protein permeability, increases ultrafiltration, and decreases cytokine levels and the proportion of peritoneal neutrophils in dialysate from rats exposed to hypertonic dialysis solution. These results suggest that exogenous HA may help to protect the peritoneal membrane during exposure to dialysis solutions. These benefits, if sustained in the clinical setting, could lead to improvements in the therapy of peritoneal dialysis.

Animals↗
PubMed2000

Hypertonicity of dialysis fluid suppresses intraperitoneal inflammation.

We studied acute and chronic intraperitoneal inflammation during dialysis performed in rats injected with phosphate-buffered saline alone (PBS) or PBS supplemented with glucose (Glu) or with mannitol (Man). In acute experiments, the result of a first dialysis with PBS in every rat (dialysis I) was compared with a second dialysis performed 24 hours later (dialysis II) using a different dialysis fluid: either PBS with 3.86 g/dL Man or PBS with 3.86 g/dL Glu. In rats exposed to hypertonic dialysis solutions (both Glu and Man), inflammatory reaction was decreased (cell count: p < 0.05; nitric oxide secretion: p < 0.05; protein in dialysate: p < 0.05). In control animals treated only with PBS (dialysis I and dialysis II), the inflammatory reactions during dialysis I and dialysis II were comparable. In chronic experiments, rats were dialyzed with the tested fluids for four weeks. Weekly, dialysate samples were taken and analyzed. At the end of the study, cell counts and protein losses were higher in the PBS-treated rats than in the other groups (cell count: p < 0.05, Glu vs PBS, and p < 0.05, Man vs PBS; protein in dialysate: p < 0.001, Glu vs PBS, and p < 0.01, Man vs PBS). We conclude that hypertonicity of the dialysis fluid inhibits the inflammatory reaction in the peritoneal cavity during peritoneal dialysis.

Acute Disease↗
PubMed1999

l-2-oxothiazolidine-4-carboxylic acid modulates function of peritoneal mesothelial cells in vitro.

The influence of the glutathione precursor, l-2-oxothiazolidine-4-carboxylic acid (OTZ), on the function of human peritoneal mesothelial cells in vitro, in conditions that mimic the in vivo effect of peritoneal dialysis solutions on mesothelium, was studied. Mesothelial monolayers were exposed to dialysis fluids (Dianeal 1.36 or Dianeal 3.86; Baxter Healthcare Corp, Round Lake, IL) that were diluted gradually with pooled-effluent dialysate obtained from patients undergoing continuous ambulatory peritoneal dialysis. In vitro exposure of mesothelium to standard dialysis fluid enhances their susceptibility to injury by hydrogen peroxide. OTZ added to dialysis solution in concentrations of 1 mmol/L prevented the toxic effect of hydrogen peroxide, probably by increasing intracellular glutathione. Mesothelial cells exposed to dialysis fluid become activated, evidenced by increased release of interleukin-6 and hyaluronan. OTZ used in concentrations of 1 mmol/L reduced that effect. Furthermore, the addition of glucose to the culture medium in a concentration of 45 mmol/L inhibits the proliferation of mesothelial cells; the presence of OTZ, 1 mmol/L, partially prevents the inhibitory effect of glucose. The results presented in this report show that by augmenting the intracellular concentration of glutathione in mesothelial cells by the addition of OTZ to the dialysis fluid, we can increase their resistance to the acute toxicity of free radicals and long-term toxicity of glucose. In addition, mesothelial cells with an increased glutathione level are less activated after their exposure to dialysis fluid.

Cell Division↗
PubMed1999

Effect of N-acetylglucosamine on function of peritoneal leukocytes.

OBJECTIVE: To compare effects of N-acetylglucosamine (NAG)-based and glucose-based dialysis fluids on the function of peritoneal leukocytes in conditions of peritoneal dialysis. DESIGN: In vitro experiments on ex vivo isolated rat peritoneal leukocytes. MATERIALS: Peritoneal leukocytes were isolated from rats on chronic peritoneal dialysis. On alternate days, fluid exchanges were performed with NAG-based or glucose-based dialysis solutions. After a 4-hour dwell, dialysate was drained and peritoneal leukocytes were incubated in vitro +/- lipopolysaccharide (LPS). Production of nitrites (index of NO synthesis), tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and interferon gamma (IFN-gamma) by unstimulated or stimulated peritoneal leukocytes originating from NAG-based or glucose-based fluid was measured. RESULTS: Dialysate cell count was lower during exchanges with NAG-based fluid (2113+/-615 cells/microL) as compared to glucose-based fluid (3643+/-1108 cells/microL; p < 0.01). Differential cell count was similar in both studied groups. Unstimulated peritoneal leukocytes from NAG-based dialysate produced more NO (nitrites) (0.65+/-0.07 micromol per 10(6) cells) than did cells from glucose-based dialysate (0.26+/-0.09 micromol per 106 cells, p < 0.01). Stimulated peritoneal leukocytes from NAG-based dialysate produced more cytokines than did cells from glucose-based dialysate: TNFalpha, 135.2+/-37.0 pg versus 70.2+/-21.8 pg per 10(6) cells respectively, p < 0.01; IL-1beta, 143.2+/-60.9 pg versus 99.1+/-22.4 pg per 10(6) cells respectively, p < 0.05; IFN-gamma, 16.2+/-12.5 pg versus 6.0+/-1.8 pg per 10(6) cells respectively, p < 0.01. CONCLUSIONS: We demonstrated that rat peritoneal leukocytes exposed in vivo to NAG-based dialysis fluid have better ability to produce inflammatory mediators than do peritoneal leukocytes from the same donor, but exposed in vivo to glucose-based dialysis solution.

Acetylglucosamine↗
PubMed1999

Bicarbonate/lactate dialysis solution improves in vivo function of peritoneal host defense in rats.

OBJECTIVE: To assess the in vivo peritoneal inflammatory reaction in rats dialyzed with neutral, bicarbonate-lactate-buffered dialysis fluid. METHODS: Chronic peritoneal dialysis was performed for 4 weeks in Wistar rats with two solutions: (1) 40 mmol/L lactate-buffered fluid, pH 5.2, with a glucose concentration of 2.27 g/dL (Lac); and, (2) 15 mmol/L lactate and 25 mmol/L bicarbonate-buffered fluid, pH 7.0-7.5, with a glucose concentration of 2.27 g/dL (Bic-Lac). After 4 weeks, two peritoneal equilibration tests (PET 1 and PET 2) were performed in all animals with each respective solution. PET 1 was done with test solutions alone, whereas, on a subsequent day, PET 2 was performed with test solutions supplemented with endotoxin [lipopolysaccharide (LPS)] to induce peritonitis. RESULTS: During PET 1 no consistent differences were detected in peritoneal permeability between the Lac and Bic-Lac groups. Total dialysate cell count in the Bic-Lac animals was lower than in rats treated with Lac fluid: that is, at 8 hours, the respective counts were 1858+/-524 cells/microL versus 2785+/-1162 cells/microL (p < 0.01). Dialysate from animals dialyzed with Bic-Lac contained more macrophages (at 4 hours: 53.6%+/-35.8% versus 35.8%+/-8.8%, p < 0.001) and fewer neutrophils (at 4 hours: 3.6%+/-1.8% versus 15.4%+/-6.1%, p < 0.001) as compared to those dialyzed with the Lac solution. Concentration of nitrites in 8-hour dwell dialysate samples from Bic-Lac rats was lower than that in the Lac group (0.98+/-0.28 micromol/mL versus 2.32+/-0.87 micromol/mL, p < 0.002), but cytokine levels in the dialysates were comparable. During PET 2, the increase in peritoneal permeability resulting from the LPS-induced inflammatory response was similar for both test solutions. Dialysate cell count was higher in the Lac group versus the Bic-Lac group (at 8 hours: 8789+/-4862 cells/microL versus 3961+/-581 cells/microL, p < 0.001), contained more neutrophils (at 8 hours: 80.0%+/-11.3% versus 54.8%+/-4.4%, p < 0.001) and fewer macrophages (at 8 hours: 6.8%+/-5.6% versus 21.2%+/-3.3%, p < 0.05). During peritonitis, we found a higher overall dialysate concentration of both tumor necrosis factor (TNFalpha: +53%, p < 0.05) and of interferon gamma (IFN-gamma: +303%, p < 0.02), in the Bic-Lac group than in the Lac group. CONCLUSIONS: A lower dialysate cell count, higher percentage of macrophages, and lower percentage of neutrophils in dialysate suggest that Bic-Lac fluid induces a diminished nonspecific inflammatory response of the peritoneal cavity during dialysis. However, after in vivo stimulation, peritoneal cells from animals dialyzed with Bic-Lac solution possess an augmented ability to produce inflammatory cytokines.

Animals↗
PubMed1999

Evaluation of the effect of uremia on peritoneal permeability in an experimental model of continuous ambulatory peritoneal dialysis in anephric rats.

Anephric rats were maintained on continuous ambulatory peritoneal dialysis (CAPD). Peritoneal permeability was assessed during a standard 4-hour peritoneal equilibration test (PET) performed with Dianeal 3.86% (Baxter Healthcare, Deerfield, Illinois, U.S.A.). The effect of uremia on peritoneal permeability was evaluated in an experimental protocol in which each animal served as its own control. In each rat, PET1 (control) was performed before removal of kidneys and PET2 (uremia) was performed four days after removal of kidneys. Net ultrafiltration during a 4-hour exchange with Dianeal 3.86% was higher during PET1 (3.8 +/- 2.3 mL) than during PET2 (-1.3 +/- 3.3 mL), p < 0.05. Peritoneal permeability to urea and glucose was similar in both series. Transperitoneal equilibration of creatinine concentration was faster in uremic animals: D/P at 4 hours was 0.94 +/- 0.06 during PET2 versus 0.77 +/- 0.08 during PET1, p < 0.001. The opposite difference was seen for total protein: D/Px 1000 after a 4-hour dwell was 51.4 +/- 19.8 during PET2 versus 70.3 +/- 12.9 during PET1, p < 0.05. Our results show that uremia modifies the permeability of the peritoneum to both water and solutes.

Animals↗
PubMed1999

[The role of cellular glucose transporters in pathogenesis of diabetic nephropathy].

The transport of glucose across plasma membranes is of paramount importance for the maintenance of cellular homeostasis and metabolism. Over the past few years it has been established that this process is mediated via a family of specialized and tissue-specific glucose transporters. It has been demonstrated that these facilitative glucose transporters may regulate the cellular uptake of glucose and consequently affect glucose metabolism. It has been suggested that increased utilization of glucose in glomerular cells results in the increased expression and activity of aldose reductase, protein kinase C and TGF-beta, which have been implicated in excessive extracellular matrix accumulation in diabetic nephropathy. In this report we review the identified forms of the glucose transporter family focusing on the systems expressed by the kidney. We also summarize the currently available experimental data suggesting that glomerular glucose transport systems may play a role in the development of diabetic nephropathy.

Animals↗
PubMed1998

[Levels of eosinophil cationic protein in serum of infants with wheezy bronchitis].

Wheezy bronchitis is one of the most important problems in pediatric pneumonology. Characteristic of bronchial inflammatory response during acute episode of wheezy bronchitis is not well known. The aim of our study was to examine eosinophil activation marker--eosinophil cationic protein(s-ECP) in infants with wheezy bronchitis. The study group consisted of 69 infants. Mean s-ECP level was 12.51 ug/l. Increased concentration was found in 13 children (18.8%). s-ECP level depended on age (the lowest value in the first three month of life), severity of symptoms and atopic status (higher value in case of severe course of disease and in group with higher IgE level)). There was no difference in s-ECP value between group of children presenting recurrent symptoms and children without respiratory problems in follow-up observation. However in group with frequent episodes of wheezing results of ECP level on first examination were higher than in group with only one or two episodes. Our observation suggests that in infants suffering from wheezy bronchitis eosinophils are activated and s-ECP correlate with severity of symptoms and atopic predisposition.

Biomarkers↗
PubMed1998

[Use of a video questionnaire for assessment of asthma prevalence in school children as part of the ISAAC epidemiological study].

The aim of this publication is the comparison of the data characterizing asthma prevalence obtained from standardized questionnaire (SQ) and video-questionnaire (VQ) used in epidemiological study ISAAC--Poznań. Number of positive answers to questions concerning wheezing ever, current wheezing, night symptoms were lower in VQ. The percentage of children reporting exercise induced asthma didn't differ in both methods. Severe asthma attacks were reported more frequently in VQ. VQ may eliminate the differences in perception and interpretation of asthma symptoms, but presentation of severe symptoms leads to underestimation of asthma problem.

Adolescent↗
PubMed1998

The effect of N-acetylglucosamine as a substrate for in vitro synthesis of glycosaminoglycans by human peritoneal mesothelial cells and fibroblasts.

The effect of N-acetylglucosamine (NAG) on in vitro synthesis of glycosaminoglycans by human peritoneal mesothelial cells and fibroblasts was studied. In contrast to isosmotic concentrations of glucose, NAG increases the synthesis of hyaluronan by mesothelial cells and fibroblasts in a dose-dependent manner. This effect of NAG can be demonstrated in the presence of increased glucose levels in a medium, or in a medium mixed with effluent dialysate obtained from continuous ambulatory peritoneal dialysis (CAPD) patients. Glucose inhibits synthesis of sulphated glycosaminoglycans by peritoneal mesothelial cells and fibroblasts, whereas NAG stimulates their production. Our results demonstrate that NAG is an effective stimulator of the in vitro glycosaminoglycans synthesis by human peritoneal mesothelial cells and fibroblasts.

Acetylglucosamine↗
PubMed1998

The characteristics of peritoneal healing after catheter insertion in a rat model of peritoneal dialysis.

The aim of this study was to characterize the process of peritoneal healing after catheter insertion in a rat model of peritoneal dialysis using a 1.36% solution (Baxter Dianeal). After catheter insertion (day 1 of experiment), 12 rats were injected daily with 20 mL of 1.36% dialysis solution for 2 weeks. Every second day a sample of 4 hour dialysate was taken from every rat for biochemical analysis, cell count, cell differentiation, and nitrites measurement. The measured parameters decreased during the experiment and stabilized during the second week after catheter insertion. In cell differentiation, we observed an increase in the number of macrophages, with a parallel decrease in the number of neutrophils that was reflected in a significant decrease in the neutrophils/macrophages ratio. Our results suggest that the process of peritoneal healing after catheter implantation in rats lasts about 2 weeks, and therefore that any biocompatibility study of peritoneal dialysis solutions in rats should be performed at least 2 weeks after catheter insertion.

Animals↗
PubMed1997

In vitro simulation of the effect of peritoneal dialysis solution on mesothelial cells.

All previous in vitro biocompatibility tests of peritoneal dialysis fluids have shown that these have inhibitory effects on the function of peritoneal mesothelium. This report presents results from in vitro experiments performed to study the effect of dialysis fluids (Dianeal 1.36 and Dianeal 3.86; Baxter, Round Lake, IL) on the function of mesothelial cells under conditions that simulate the in vivo state of these solutions in the peritoneal cavity. Thus, cells were initially exposed only to the unused fluids that were thereafter gradually diluted (over 4 hours) with pooled effluent dialysate from continuous ambulatory peritoneal dialysis patients. During the following 20 hours, cells were incubated in a mixture of unused fluid (10% vol/vol) and dialysate effluent (90% vol/vol). The mesothelial cells exposed to dialysis fluids under such conditions became activated cells compared with exposed to dialysate effluent (control) alone. Thus, synthesis by mesothelial cells of all tested substances was enhanced during exposure of the mesothelium to the dialysis fluids: interleukin-6: Dianeal 1.36, +257%; Dianeal 3.86, +181% (both P < 0.05); hyaluronic acid: Dianeal 1.36, +72%; Dianeal 3.86, +63% (both P < 0.05); tissue plasminogen activator: Dianeal 3.86, +33% (P < 0.05); and plasminogen activator/inhibitor-1: Dianeal 1.36, +28%; Dianeal 3.86, +38% (both P < 0.05). Our results show that the peritoneal mesothelium becomes activated when it is exposed to acidic, hyperosmotic dialysis fluids diluted with the dialysate effluent, in a manner that imitates the in vivo changes in these solutions during their intraperitoneal dwell.

Cells, Cultured↗