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Biomedical subjects

A Breborowicz

Publications and source records attributed to A Breborowicz.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Effect of methotrexate, doxorubicin and mitoxantrone on human peritoneal mesothelial cell function in vitro.

Recent studies have demonstrated that intraperitoneal instillation of dialysis solutions and drug additives may adversely affect the function of peritoneal cell populations. Therefore the aim of the present investigation was to examine the short-term effects of antineoplastic agents on human peritoneal mesothelial cells (HPMC). We have assessed the integrity of HPMC membrane and mechanisms of intracellular potassium transport. There was no evidence of significant cytotoxicity (as measured by 86Rb release) during a 60-min exposure of HPMC to either methotrexate (10(-6)-10(-4) M), doxorubicin (10(-7)-10(-5) M) or mitoxantrone (10(-7)-10(-5) M). In HPMC exposed to doxorubicin (10(-6) M) the intracellular transport of potassium, as assessed with 86Rb as its analogue, was not affected. Methotrexate (10(-5) M) diminished Na,K-ATPase activity and simultaneously enhanced the 86Rb transport via furosemide-sensitive pathway. Mitoxantrone reduced the furosemide-sensitive 86Rb influx in a dose-dependent manner and at a concentration of 10(-4) M it also impaired the ouabain-dependent 86Rb influx. These data demonstrate that antineoplastic agents interfere with HPMC function which might contribute to the oncostatic-induced peritoneal toxicity.

Cells, Cultured↗
PubMedDate not supplied

Changes in volume of peritoneal mesothelial cells exposed to osmotic stress.

OBJECTIVE: To evaluate changes in volume of mesothelial cells exposed to hypertonic medium and the role of volume regulatory mechanisms in adaptation to hyperosmolality. DESIGN: Experiments were performed on primary cultures of human peritoneal mesothelial cells. Cell volume was estimated by measuring equilibrated (intracellular/extracellular space) 14C-urea in cellular water. Cells in monolayers were exposed to hyperosmotic media and changes in cellular water or intracellular uptake of 3H-proline were measured. RESULTS: Exposure of mesothelial cell monolayers to hyperosmotic media reduced the cell volume; the effect was proportional to the osmolality of the medium. Volume of cells exposed to medium supplemented with glucose (180 mmol/L) decreased by 26%, p < 0.001, after 30 minutes' incubation. Prolonged exposure of mesothelial cells to hyperosmotic medium resulted in gradual recovery, after initial decline, of their volume. Intracellular uptake of amino acid 3H-proline increased after 240 minutes' exposure of the mesothelial cells to medium supplemented with glucose (90 mmol/L) (+40%, p < 0.05). When cells cultured for 7 days in medium supplemented with glucose (45 mmol/L) were exposed to medium with low glucose content (5 mmol/L) their volume increased by 17%, p < 0.05. CONCLUSION: Mesothelial cells shrink after exposure to hypertonic medium. Increased intracellular uptake of amino acids may be one of the regulatory mechanisms that ensure subsequent volume increase in these cells. Mesothelial cells chronically exposed to hypertonic medium swell after transfer to a medium with physiologic osmolality.

Cells, Cultured↗
PubMedDate not supplied

Role of peritoneal mesothelial cells and fibroblasts in the synthesis of hyaluronan during peritoneal dialysis.

OBJECTIVE: To assess the in vitro synthesis rate of hyaluronan (HA) by human peritoneal mesothelial cells and peritoneal fibroblasts in the presence of effluent dialysate from continuous ambulatory peritoneal dialysis (CAPD) patients. METHODS: We used primary cultures of human peritoneal mesothelial cells and peritoneal fibroblasts from nonuremic patients to study the effect of interleukin-1beta (II-1beta) and pooled effluent dialysate, from noninfected and infected CAPD patients, on the synthesis of HA by the studied cells. We also tested the effect of the exogenous HA on the synthesis rate of that glycosaminoglycan. We studied the correlation between HA concentration in effluent dialysate and the stimulatory effect of that solution on in vitro synthesis of HA by mesothelium. RESULTS: Peritoneal fibroblasts produce more HA than mesothelial cells. Noninfected effluent dialysates or dialysates from CAPD patients with peritonitis stimulate synthesis of HA by mesothelial cells and fibroblasts. Interleukin-1beta has a stimulating effect, which was synergistic with effluent dialysates, on the synthesis of HA by mesothelium and peritoneal fibroblasts. A weak correlation was demonstrated between the level of HA in effluent dialysate and the stimulatory effect of that dialysate on in vitro synthesis of HA by mesothelial cells. CONCLUSIONS: Peritoneal fibroblasts are a more potent source of HA than are mesothelial cells, but probably the latter are the main source of HA in drained dialysate. Although effluent dialysates contain factors that stimulate the production of HA by mesothelium, there is weak correlation between that stimulatory effect and the actual HA concentration in the dialysate, which, in some patients, might suggest low "responsiveness" of the membrane.

Adjuvants, Immunologic↗
PubMedDate not supplied

Intraperitoneal hyaluronan administration in conscious rats: absorption, metabolism, and effects on peritoneal fluid dynamics.

BACKGROUND: Hyaluronan (HA) is a major component of interstitial tissue that participates in fluid homeostasis, response to inflammation, and wound healing. Previous studies have shown that intraperitoneal administration of HA can affect peritoneal fluid transport during short peritoneal dialysis exchanges in anesthetized rats. We sought to investigate the effect of high molecular weight HA on peritoneal permeability in conscious rats during dialysis exchanges up to 8 hours in duration. In addition, we sought to investigate the absorption of HA from the peritoneal cavity, its accumulation in peritoneal tissues, and its metabolism in normal and uremic rats. METHODS: Experiments were performed on male Wistar rats infused with 30 mL peritoneal dialysis solution (Dianeal, Baxter Healthcare; Castelbar, Ireland) containing 10 mg/dL HA or with Dianeal alone (control). Peritoneal fluid removal (net ultrafiltration), permeability to glucose, creatinine, and total proteins, and tissue and blood levels of HA were determined in separate groups of rats at 1,2, 4, 6, and 8 hours after intraperitoneal infusion. Hyaluronan appearance and disappearance from plasma were also studied for 24 hours in separate groups of normal and uremic rats. RESULTS: Net ultrafiltration was significantly greater (27%) in rats infused with HA at 4, 6, and 8 hours (p < 0.01) compared to controls. Transperitoneal equilibration of protein was reduced by 27% (p < 0.001) at 4 hours and by 30% (p < 0.01) at 8 hours. During the 8-hour exchange, peritoneal clearance of creatinine increased by 27% (p < 0.01), whereas the clearance of total protein decreased by 27% (p < 0.005). After 8 hours, 25.7% +/- 3.1% of the administered HA was absorbed from the peritoneal cavity, peritoneal tissue HA concentration was increased by 117% (p < 0.001), and plasma HA levels increased by 435% (p < 0.001). Plasma HA levels returned to normal within 24 hours after intraperitoneal administration in both healthy and uremic rats. CONCLUSIONS: Hyaluronan added to dialysis fluid is absorbed from the peritoneal cavity and accumulates in peritoneal tissues. Hyaluronan supplementation produces changes in peritoneal permeability, leading to higher net ultrafiltration and peritoneal creatinine clearance, whereas total protein clearance decreases. The HA that is absorbed from the peritoneal cavity appears to be rapidly metabolized in both healthy and uremic rats.

Absorption↗
PubMedDate not supplied

[Congenital angioneurotic edema in an 11-year-old girl].

A case of a 11-year girl with the inherited angioedema is presented. Lack of improvement following antiallergic therapy and familial history of the disease were the base of studies leading to the diagnosis of this rare syndrome. Preliminary diagnosis was confirmed by C1q inhibitor and blood level of C4 assays.

Angioedema↗
PubMedDate not supplied

Effect of ethacrynate sodium on transmesothelial transfer of solutes.

The effect of ethacrynate sodium on transmesothelial fluxes of solutes was studied in vitro. Ethacrynate sodium increased the mesothelial permeability to urea, chloride and sodium. The increase was transient, reproducible and not dependent on cellular metabolism.

Animals↗
PubMedDate not supplied

[Ultrasound examination in presentation A for diagnosis of maxillary sinusitis in childhood].

Maxillary sinusitis is frequent in childhood. This study aimed at evaluating the value of ultra sound in presentation A in the diagnosis of maxillary sinusitis in childhood. Altogether 324 maxillary sinuses in 162 children were examined. A value of ultra sound examination was verified comparing the obtained results with the results of X-rays, considering three classifications of the latter. Besides the attempt of correlation of the results, ultra sound specificity and sensitivity were evaluated. Relatively high sensitivity and relatively low specificity of ultra sound technique were noted. It seems that ultra sound examination in presentation A may serve as a screening technique in children. Being sensitive and safe, this technique may be used in patients who require frequent examinations in persisting chronic disorders or recurrent maxillary sinusitis. However, the obtained results should be verified with X-rays because of the low specificity of ultra sound examination, especially prior to therapy of patients with unclear clinical picture of the disease.

Child, Preschool↗
PubMedDate not supplied

Synthesis of hyaluronic acid by human peritoneal mesothelial cells: effect of cytokines and dialysate.

OBJECTIVE: To assess effects of the inflammatory cytokines (IL-1-beta, TNF-alpha, TGF-beta 1) and dialysate effluent on synthesis of hyaluronic acid by human peritoneal mesothelial cells (HMC) in in vitro culture. METHODS: Dialysate effluent was collected after the overnight dwell of Dianeal 1.5% from patients during CAPD training. HMC were obtained from omentum from nonuremic donors or were harvested from the dialysate effluent from CAPD patients. Synthesis of hyaluronic acid was studied on monolayers of HMC, which were deprived of serum 48 hours prior to experiment. Effects of cytokines were tested in a medium with low serum concentration (0.1%) or in medium mixed (1:1 v/v) with the autologous dialysate. Hyaluronic acid level in medium was measured with radioimmunoassay. RESULTS: Cytokines enhanced synthesis of hyaluronic acid by HMC, and the strongest effect was induced by IL-1. Effluent dialysate stimulates synthesis of hyaluronic acid stronger than 10% FCS. Effluent dialysate and IL-1 synergistically enhance synthesis of hyaluronic acid by HMC. CONCLUSION: Effluent dialysate from CAPD patients stimulates production of hyaluronic acid by HMC and acts synergistically with cytokines.

Cells, Cultured↗
PubMedDate not supplied

Insulin stimulates the activity of Na+/K(+)-ATPase in human peritoneal mesothelial cells.

OBJECTIVE: To assess the effect of insulin on the Na+/K(+)-ATPase expression and activity in human peritoneal mesothelial cells (HPMC). METHODS: HPMC were isolated from the omental tissue of non-uremic patients, grown to confluence and rendered quiescent by serum deprivation for 24 hours. The activity of Na+/K(+)-ATPase was determined by measuring the ouabain-sensitive 86Rb uptake. To assess whether the effect of insulin was related to changes in [Na+]i the sodium influx was measured with 22Na and the activity of Na+/K(+)-ATPase was assessed in the presence of amiloride. Expression of Na+/K(+)-ATPase alpha 1,alpha 2 and beta 1-subunit mRNAs was determined by RT/PCR. RESULTS: Exposure of HPMC to insulin resulted in a time- and dose-dependent increase in the Na+/K(+)-ATPase activity. After 60 minutes the ouabain-sensitive 86Rb uptake (cpm/10(4) cells) was increased from 6650 +/- 796 in control cells to 9763 +/- 1212 in HPMC exposed to 100 mU/mL insulin (1.5-fold increase; n = 4, P < 0.05). In addition, incubation of HPMC with 100 mU/mL insulin resulted in a time-dependent increase in the 22Na influx. Pre-exposure of HPMC to 1mM amiloride reduced the activity of Na+/K(+)-ATPase but did not block the stimulatory effect of insulin. RT/PCR analysis revealed that HPMC constitutively expressed alpha 1- and beta 1-subunit mRNAs while the alpha 2-subunit mRNA was barely detectable. Exposure of HPMC to insulin for up to 24 hours was not associated with any changes in the expression of either alpha 1, alpha 2 or beta 1-subunit. CONCLUSION: Insulin stimulates the Na+/K(+)-ATPase activity in HPMC in a time- and dose-dependent manner. This effect appears to mediated by an increase in [Na+]i and is not related to alterations in Na+/K(+)-ATPase subunit mRNAs expression.

Cells, Cultured↗
PubMedDate not supplied

Peritoneal surface area and its permeability in rats.

OBJECTIVE: Evaluation of peritoneal surface area and its permeability during dialysis in rats of various ages. DESIGN: Study I: planimetry of peritoneum and its topographic areas was performed in 47 rats of various ages (8-30 weeks). Study II: net ultrafiltration (UF), dialysate-to-serum ratios for urea, creatinine, albumin, and total protein as well as their peritoneal permeability coefficients, were measured during a 1-hour peritoneal exchange with Dianeal 2.5%, in 21 rats of different ages (9-30 weeks) and with various peritoneal surface areas. ANIMALS: Male Wistar rats. RESULTS: The peritoneal surface area in rats increases during aging, but young animals with lower body weight have a relatively larger peritoneal surface area than older, larger animals. The area of the topographic fragments of peritoneum expressed as a percentage of the total peritoneal surface is steady during aging. Efficiency of transperitoneal water removal expressed as net UF per amount of absorbed glucose declines in older animals, with larger peritoneal surface areas. Dialysate/serum ratio of solutes transported from blood to dialysate is proportional to peritoneal surface area. Permeability coefficient (K) of peritoneum to urea and creatinine is unchanged during the aging of animals. However peritoneal permeability (K) to albumin increases during aging, with the opposite tendency for total proteins. CONCLUSIONS: Kinetics of peritoneal dialysis in rats of different ages is determined by peritoneal surface area and permeability of peritoneum to individual solutes.

Age Factors↗
PubMedDate not supplied

The effect of a nitric oxide inhibitor (L-NAME) on peritoneal transport during dialysis in rats.

OBJECTIVE: To assess the effect of an inhibitor of nitric oxide synthesis [N(G)-nitro-L-arginine methyl ester (L-NAME)] on peritoneal transport during peritoneal dialysis (PD) and peritonitis in rats. METHODS: The authors studied peritoneal transport of small and large solutes, and net ultrafiltration (UF) in rats during PD with Dianeal 3.86 (Baxter, McGaw Park, IL, U.S.A.). They evaluated the effect of L-NAME used as an additive to dialysis fluid in concentrations 0.5-5 mg/mL on peritoneal transport of small and large molecules and on transperitoneal UF. In addition, they studied the effect of L-NAME (5 mg/mL) during acute peritonitis induced by lipopolysaccharides (5 microg/mL) given intraperitoneally. RESULTS: The addition of L-NAME to dialysis fluid increased the selectivity of the peritoneum and net UF during dialysis. Lipopolysaccharides used as an additive to the dialysis fluid, together with L-NAME, did not induce changes in transperitoneal transport of small and large solutes and did not cause a significant decline in net UF. L-NAME given intraperitoneally reduced both local and systemic production of nitric oxide, which might explain its effects on peritoneal transport. CONCLUSIONS: Nitric oxide is an important mediator of changes in peritoneal transport and its effect is especially significant during peritonitis.

Animals↗