Biomedical subjects

M Cendoroglo

Publications and source records attributed to M Cendoroglo.

17 recordsLinked to original sources

PubMed2005

Lack of impact of hepatitis C virus coinfection in end-stage renal disease patients with hepatitis B virus infection.

INTRODUCTION: Hepatitis B virus (HBV) and hepatitis C virus (HCV) coinfection results in more severe forms of liver disease in nonuremic patients; however, the impact of HCV coinfection is not clearly known in end-stage renal disease (ESRD) patients with HBV infection. We sought to determine the impact of HCV coinfection in HBV-infected ESRD patients. PATIENTS AND METHODS: The HBsAg-positive ESRD patients evaluated between March 1999 and May 2003 were divided into two groups: group B, HBV infection alone, and group BC, HBV-HCV coinfection (anti-HCV-positive). Both groups were compared regarding epidemiological, laboratory, and histological findings. A liver biopsy was obtained in cases with evidence of viral replication and/or elevated alanine aminotransferase. RESULTS: One hundred patients (73% men) with mean age of 42 +/- 11 years (55 patients in group B and 45 in group BC) were studied. Comparison between groups showed a difference in time on hemodialysis and duration of infection, which were higher in group BC (P < .001 and P = .001, respectively) and in history of blood transfusion, which was also more frequent in group BC (P = .04). Liver biopsies, obtained from 15 patients in group B and 28 patients in group BC, showed no difference in frequency of septal fibrosis (60% in group B vs 48% in group BC, P = .46) or interface hepatitis (73% vs 71%, P = .99). CONCLUSIONS: HBV-HCV coinfection was related to a longer time on hemodialysis, longer duration of infection, and history of blood transfusion. Contrary to nonuremic patients, HCV coinfection was not associated with more severe forms of liver disease in ESRD patients.

Adult↗

PubMed2004

High prevalence of low bone mineral density in pre-dialysis chronic kidney disease patients: bone histomorphometric analysis.

UNLABELLED: Chronic kidney disease (CKD) leads to reduced bone mineral density (BMD) in pre-dialysis and dialysis patients. A few studies have used dual-energy x-ray absorptiometry (DEXA) to assess BMD in pre-dialysis CKD patients and have shown low BMD to be highly prevalent. Until now there have been no studies reporting the histological features of low BMD in pre-dialysis CKD patients. AIM: To determine the prevalence and histological features of low BMD in pre-dialysis CKD patients. METHOD: Pre-dialysis CKD patients (n = 103, 46 females/57 males), median creatinine clearance of 29 (10 - 78) ml/min/ 1.73 m2, were evaluated using biochemical analysis and DEXA. Bone biopsies were obtained from those with low BMD. RESULTS: Fifty (48.5%) out of the 103 patients had low BMD (LBD group) and 53 (51.5%) had normal BMD (NBD group). The risk for low BMD was increased in those patients with alkaline phosphatase levels above 190 U/l and intact-PTH (iPTH) below 70 pg/ml (p < 0.05). Demographic and biochemical parameters from both groups were comparable, except for lower body mass index (BMI) in LBD subjects (p = 0.04). Women who had been post-menopausal for at least 1 year comprised 65% (13/20) and 50% (13/26) of the LBD and NBD groups, respectively (p = NS). In 40 LBD patients, bone histomorphometry revealed adynamic bone disease (ABD, 52.5%), osteomalacia (OM, 42.5%) and mixed bone disease (MBD, 5%). Trabecular bone volume (BV/TV) was lower in ABD and OM patients. A nearly significant association was found between ABD and iPTH < or = 150 pg/ml (p = 0.056), whereas higher values of iPTH were associated with OM. Total alkaline phosphatase < or = 190 U/l was significantly associated with ABD, whereas higher values were associated with OM. No correlation was observed between BV/TV and BMD. CONCLUSION: Low BMD is frequent in pre-dialysis CKD patients, and low turnover bone disease, manifesting as ABD and OM, was the hallmark of this bone loss.

Absorptiometry, Photon↗

PubMed2001

Apoptosis of leukocytes: basic concepts and implications in uremia.

Circulating blood leukocytes have short life expectancies and end their lives by committing programmed cell death or apoptosis. Apoptosis is an active form of cell death that is initiated by a number of stimuli and is intricately regulated. Apoptosis in both excessive and reduced amounts has pathological implications. Evidence suggests that apoptosis may play a role in the pathophysiology of immune dysfunction in uremia. Indeed, accelerated programmed cell death has been observed in lymphocytes, monocytes, and polymorphonuclear leukocytes among patients with chronic renal failure. This may be due in part to the retention of uremic toxins. The aim of this article is to review the evidence for accelerated leukocyte apoptosis, key regulatory apoptotic pathways, and the possible role of this highly organized process in the pathogenesis of immune dysfunction in uremia.

Apoptosis↗

PubMed2001

Customized bicarbonate buffered dialysate and replacement solutions for continuous renal replacement therapies: effect of crystallization on the measured levels of electrolytes and buffer.

The aim of this study was to investigate the impact of the addition of calcium to bicarbonate solutions for continuous renal replacement therapy (CRRT). We tested single bag (bicarbonate and calcium mixed 24 h before testing) and double bag solutions (mixed immediately before) with and without the addition of 4 mEq/L of acetate. Prescribed calcium varied from 0 to 5 mEq/L. All test solutions containing calcium showed crystallization at light microscopy. The double bag solutions decreased but did not prevent crystallization. The addition of acetate did not interfere with crystallization. Crystallization, as measured by the weight of the crystals after filtration of the solutions, showed a significant positive correlation with the calcium deficit (prescribed minus measured) and with partial pressure of carbon dioxide. The measured level of calcium was lower than expected and correlated with crystallization. Our results suggest that the use of bicarbonate solutions containing calcium as replacement fluids for CRRT is a potentially unsafe procedure.

Bicarbonates↗

PubMed2001

Resting energy expenditure in pre-dialysis diabetic patients.

BACKGROUND: The metabolic derangements of diabetes mellitus (DM) associated with those of chronic renal failure (CRF) may interfere with the energy and protein balance of patients with both diseases. The aim of this study was to verify whether the resting energy expenditure (REE) of non-dialysis chronic renal failure diabetic patients differs from that of chronic renal failure patients without DM. METHODS: REE was measured by indirect calorimetry in 24 CRF diabetic patients (CRF diabetes group), matched for age, gender, and degree of renal impairment to 24 CRF patients without DM (CRF control group). RESULTS: The CRF diabetes group had a significantly higher REE (1538+/-230 kcal/day) than the CRF control group (1339+/-315 kcal/day, P = 0.009). This difference was maintained even when the REE was adjusted for lean body mass (LBM; 30.3+/-4.3 vs 26.3+/-5.4 kcal/kg LBM/day, P = 0.004). Mean protein intake was significantly higher in the CRF diabetes than in the CRF control group (0.89+/-0.20 vs 0.76+/-0.25 g/kg/day, P = 0.02). Mean protein equivalent of nitrogen appearance (PNA) was also significantly higher in the CRF diabetes patients (1.21+/-0.31 vs 1.03+/-0.22 g/kg/day, P = 0.02), reflecting a higher protein intake and/or elevated protein breakdown. Accordingly, REE was directly correlated with PNA mainly in the CRF diabetes group (r = 0.57, P < 0.003). CONCLUSION: Metabolic disturbances of poorly controlled DM may account for the higher REE observed in the CRF diabetes group. The role of the apparently higher protein breakdown in this increased REE remains to be clarified.

Aged↗

PubMed2001

Parathyroid hormone changes during phosphorus load in patients with chronic renal insufficiency with low serum parathyroid hormone or adynamic bone disease.

UNLABELLED: Adynamic bone disease (ABD) is frequently associated with low serum parathyroid hormone (PTH) concentrations. Many clinical and therapeutic conditions have been associated with ABD, and recently, a low phosphorus intake accompanied by low serum concentration of phosphorus and PTH has been described. AIM: To evaluate the parathyroid gland response of chronic renal insufficiency patients (CRI) with low serum PTH or ABD to a phosphorus load. METHODS: We examined the effects of 0.5 and 1.0 g/d of phosphorus load over a period of 60 days in 18 patients with mild CRI with a bone biopsy showing ABD (n = 7) or with low serum PTH (serum intact PTH < or = 40 ng/l) and serum phosphorus < 4.5 mg/dl (n = 11). RESULTS: Serum intact PTH increased significantly only after 1 g of phosphorus (58.5 to 83 ng/l) with a median percent increase of 72%. PTH secretion increased more in patients with lower basal PTH levels (81%). Serum phosphorus did not change significantly and urinary phosphorus increased from 487 to 1,062 mg/dl (p < 0.05). Significant decreases in serum ionized calcium (from 1.26 to 1.19 mmol/l) and calcitriol (from 34.5 to 24.9 pg/ml) were observed. Changes in PTH were inversely correlated with changes in serum ionized calcium (r = -0.54, p < 0.05) and the final PTH concentrations were positively correlated with changes in serum phosphorus (r= 0.52, p < 0.05). CONCLUSIONS: The parathyroid glands of chronic renal insufficiency patients with "relative hypoparathyroidism" or ABD responded to a phosphorus load with an increase in serum PTH levels. The decrease in serum ionized calcium and calcitriol as well as minimal changes in serum phosphorus appeared to be involved in this response.

Adult↗

PubMed2000

Quality of life at the initiation of maintenance dialysis treatment--a comparison between the SF-36 and the KDQ questionnaires.

OBJECTIVE: To evaluate the construct validity of the Medical Outcomes Study Questionnaire 36-Item Short Form Health Survey (SF-36) and to assess the quality of life of patients with end-stage renal disease (ESRD) at the initiation of maintenance dialysis treatment. METHODS: Cross-sectional study. SETTING: Eight ambulatory dialysis units in São Paulo city, Brazil. STUDY PARTICIPANTS: Eighty ESRD patients at the initiation of chronic dialysis program and consecutively accepted for treatment in selected units in 1998. MAIN OUTCOME MEASURES: Quality of life as measured by the dimensions of the SF-36 questionnaire. The 'Kidney Disease Questionnaire' was used in a subgroup of patients to evaluate the validity of the SF-36. RESULTS: Median (range) scores of the SF-36 dimensions (ranging from 0 to 100, higher scores representing better quality of life) were: Physical Function 70 (0-100), Role Limitations due to Physical Problems 25 (0-100), Bodily Pain 62 (0-100), General Health 57 (5-100), Vitality 55 (10-100), Social Function 63 (0-100), Role Limitations due to Emotional Problems 34 (0-100) and Mental Health 68 (0-100). SF-36 dimensions correlated significantly with those of the 'Kidney Disease Questionnaire' (correlation coefficients ranging from 0.23 to 0.68). CONCLUSIONS: The SF-36 was shown to have construct validity when used in patients with ESRD in Brazil. The quality of life of ESRD patients is impaired at the initiation of dialysis treatment and this was clearly evidenced in the Role Limitations due to Physical Function and Emotional Function items. Greater attention should be given to interventions that could improve the quality of life parameters at the initiation of dialysis treatment.

Adult↗

PubMed2000

Impact of dialyzer membrane selection on cellular responses in acute renal failure: a crossover study.

BACKGROUND: When acute renal failure (ARF) is severe enough to require dialysis, in-hospital mortality rates approach 60%. These alarming figures have been ascribed in part to advanced age and the high prevalence of comorbid conditions. In the past several years, a number of attempts have been made to investigate the impact of dialyzer membrane type on clinical outcomes. Unfortunately, to date, clinical studies addressing this question have reported conflicting results. METHODS: This crossover study examined the effect of dialyzer membrane type on cytokine synthesis by peripheral blood mononuclear cells (PBMCs), superoxide release by neutrophils, and apoptosis or programmed cell death of neutrophils in 24 patients with ARF requiring intermittent hemodialysis. The patients were assigned in an alternate order to a low-flux cellulose acetate (CA) or polysulfone (PS) dialyzer. After three consecutive dialysis sessions, patients were crossed over to the second dialyzer for three additional treatments. These cellular responses were measured upon dialyzer assignment and at the third and sixth dialysis session in relationship to the dialyzer type. RESULTS: The results of the study showed no impact of dialyzer biocompatibility on synthesis of tumor necrosis factor-alpha (TNF-alpha) or interleukin 10 (IL-10) by PBMCs, superoxide release by neutrophils, or neutrophil apoptosis. This held true regardless of the initial dialyzer assignment. Furthermore, there was no correlation between dialysis adequacy (measured by single-pool Kt/V) and postdialysis cellular responses. CONCLUSIONS: In summary, this study refines the question of biocompatibility by comparing a substituted cellulose rather than unsubstituted cellulose dialyzer to a PS dialyzer in the setting of ARF. The results failed to demonstrate a dialyzer advantage on the selected cellular responses.

Acute Kidney Injury↗

PubMed2000

Nutritional status of hemodialysis patients with secondary hyperparathyroidism.

The repercussions of secondary hyperparathyroidism on the nutritional status of chronic renal failure patients have not been well established. Therefore, the aim of this study was to compare the nutritional indices of hemodialysis patients with and without secondary hyperparathyroidism. Sixteen hemodialysis patients with serum parathyroid hormone (PTH) levels higher than 420 pg/ml (hyperparathyroidism group) were matched for gender, age and length of dialysis treatment to 16 patients with serum PTH between 64 and 290 pg/ml (control group). The following parameters were assessed: anthropometric indices (body mass index, skinfold thickness, midarm muscle circumference and body fat), 4-day food diaries, protein catabolic rate, biochemical indices (blood urea nitrogen, serum creatinine, albumin, ionized calcium, inorganic phosphorus, serum alkaline phosphatase, PTH, pH and HCO(3)) and dialysis efficiency. We did not observe differences in the anthropometric indices between the two groups. Only calcium intake was significantly different between groups (307.9 mg/day for the hyperparathyroidism group vs 475.8 mg/day for the control group). Protein catabolic rate tended to be higher in the hyperparathyroidism group compared to the control group (1.3 vs 0.9 g kg(-1) day(-1); P = 0.08). Except for blood urea nitrogen (86.4 vs 75.7 mg/dl), alkaline phosphatase (175 vs 65 U/l) and PTH (898 vs 155 pg/ml), no other differences were found between groups in the biochemical indices studied. PTH was directly correlated with protein catabolic rate (r = 0.61; P<0.05) and length of dialysis (r = 0.53; P<0.05) only in the hyperparathyroidism group. Considering the indices used, we could not demonstrate the deleterious effect of high PTH levels on the nutritional status of hemodialysis patients. Indirect evidence, however, suggests an action of PTH on protein metabolism.

Adult↗

PubMed1999

Shiga toxin induces superoxide production in polymorphonuclear cells with subsequent impairment of phagocytosis and responsiveness to phorbol esters.

The role of inflammatory cells in the pathogenesis of hemolytic-uremic syndrome induced by Shiga toxin (Stx)-producing Escherichia coli remains unclear. The hypothesis that Stx has direct effects on polymorphonuclear cell (PMN) viability and function was examined by measuring apoptosis, necrosis, phagocytosis, and spontaneous and phorbol myristate acetate (PMA)-stimulated production of reactive oxygen intermediates. PMN from 6 healthy persons were exposed to medium, Stx1 (0.01-100 ng/mL), or heat-inactivated Stx1 or Stx1 B subunit (100 ng/mL). Stx1 induced a prominent dose-dependent respiratory burst from PMN at doses as low as 0.01 ng/mL; they were less responsive to PMA stimulation and had reduced ability for phagocytosis. This dysfunction was not due to cell death, as the magnitude of apoptosis and necrosis of PMN treated with Stx1 (100 ng/mL) for 20 h was identical to that of medium control. These results suggest that Stx has direct effects on PMN that could contribute to tissue injury early in the disease.

Apoptosis↗

PubMed1999

Neutrophil apoptosis and dysfunction in uremia.

The high prevalence of bacterial infections among patients with end-stage renal disease suggests that "professional" phagocytes such as neutrophils are functionally impaired. This dysfunction has been ascribed to uremic toxins, malnutrition, and dialysis. The aim of this study was to investigate the contribution of apoptosis to neutrophil dysfunction in uremia. Neutrophils harvested from uremic patients (n = 6) and age-/gender-matched healthy control subjects (n = 6) were incubated with either 50% autologous plasma or 10% fetal calf serum. After 24-h incubation, apoptosis was quantified by flow cytometry by using propidium iodide nuclear staining. Neutrophils from healthy volunteers were also incubated with either 50% heterologous normal or uremic plasma. After 24-h incubation, apoptosis was quantified by flow cytometry and transmission electron microscopy. In addition, superoxide production was determined by measuring the capacity to reduce ferri- to ferro-cytochrome C by using 4-beta-phorbol 12-beta-myristate 13-alpha-acetate or N-formyl methionyl-leucyl-phenylalanine (fMLP) for stimulus. Phagocytosis was determined by the uptake of 14C-labeled heat-killed Staphylococcus aureus. Compared with normal neutrophils, uremic neutrophils demonstrated greater apoptosis in the presence of autologous plasma (9 +/- 4 versus 19 +/- 6%, P = 0.01) as well as 10% fetal calf serum (19 +/- 7 versus 31 +/- 6%, P = 0.03). Furthermore, compared with normal neutrophils exposed to heterologous normal plasma, those exposed to heterologous uremic plasma exhibited higher apoptosis rates (19 +/- 3 versus 40 +/- 5%, P = 0.002), lower tMLP-stimulated superoxide production (22.6 +/- 2.5 versus 15.5 +/- 1.1 nmol O2*-/3.12 x 10(5) cells/30 min, P = 0.01), and a lower phagocytosis index (38 +/- 3% versus 27 +/- 5%, P = 0.04). Apoptosis correlated inversely with fMLP-stimulated superoxide production (r = -0.60, P = 0.04) and phagocytosis (r = -0.57, P = 0.05). These results suggest that uremic neutrophils undergo accelerated in vitro apoptosis. Furthermore, uremic plasma accelerates apoptosis of normal neutrophils, resulting in a dysfunctional pattern that is similar to that observed in uremia.

Apoptosis↗

PubMed1998

Interleukin-1 receptor antagonist synthesis by peripheral blood mononuclear cells in hemodialysis patients.

BACKGROUND: Pro-inflammatory cytokines like interleukin (IL)-1 beta and tumor necrosis factor-alpha (TANF-alpha) are believed to play a significant role in dialysis-related morbidity. It has been previously demonstrated that the endogenous synthesis of interleukin-1 receptor antagonist (IL-1Ra) is a reliable marker of the level of IL-1 beta synthesis in hemodialysis (HD) patients. In this study, we assessed the impact of clinical and laboratory variables on IL-1Ra synthesis by peripheral blood mononuclear cells (PBMC) in patients on HD with unsubstituted cellulose dialyzers. METHODS: IL-1Ra by PBMC was measured by a specific non-cross-reactive radioimmunoassay. Day to day variation in cytokine synthesis, the correlation between cytokine synthesis under different in vitro stimulatory conditions, and the influence of clinical and laboratory variables on cytokine synthesis were studied. RESULTS: Although there was a trend towards greater IL-1Ra synthesis by unstimulated, endotoxin-stimulated and IgG-stimulated PBMC drawn before the second and third dialysis sessions of the week when compared to the first dialysis treatment, this was not statistically significant. There was a strong correlation between IL-1Ra synthesis by PBMC cultured under different stimulatory conditions that was best observed between IL-1Ra cell content and from endotoxin-stimulated PBMC (r = 0.51, P = 0.0001), and endotoxin- and IgG-stimulated PBMC (r = 0.44, P = 0.0001). In addition, there was a close correlation between total synthesis (cell associated and secreted) and secreted levels of IL-1Ra in unstimulated (r = 0.59, P = 0.0001) and endotoxin-stimulated PBMC (r = 0.69, P = 0.0001). Interestingly, there was an inverse correlation between IL-1Ra synthesis and duration of dialysis that was strongest for secreted IL-1Ra from unstimulated (r = -0.50, P = 0.002) and endotoxin-stimulated PBMC (r = -0.34, P = 0.04). There was no significant correlation between IL-1Ra synthesis by PBMC and other clinical and laboratory indices. CONCLUSIONS: The observations from this study indicate that: (1) in HD patients, there were no significant differences in cytokine synthesis by PBMC drawn before the three different dialysis treatments during the week; (2) there is a close relationship between IL-1Ra synthesis from PBMC cultured under different stimulatory conditions; (3) the secreted levels of IL-1Ra correlate directly with total synthesis (cell-associated and secreted); (4) with the exception of duration of dialysis, none of the other clinical or laboratory parameters correlated with cytokine synthesis; and (5) the diminished endotoxin- or IgG-stimulated IL-1Ra synthesis with increasing time on dialysis is possibly another sign of the impaired host-defense system in patients on long-term hemodialysis.

Cells, Cultured↗

PubMed1998

Effect of glucose concentration, osmolality, and sterilization process of peritoneal dialysis fluids on cytokine production by peripheral blood mononuclear cells and polymorphonuclear cell functions in vitro.

We sought to investigate the effects of high glucose concentration, osmolality, and heat sterilization of peritoneal dialysis fluids on tumor necrosis factor-alpha (TNF-alpha) production by peripheral blood mononuclear cells (PBMC) and polymorphonuclear cell (PMN) functions. Blood samples were obtained from eight healthy volunteers. PBMCs and PMNs were harvested by centrifugation with Ficoll-Hypaque (Sigma, St Louis, MO). PBMC were incubated with an equal volume of test fluids and RPMI for 4 hours (pH equilibrated), followed by incubation for 20 hours in RPMI with or without endotoxin (10 ng/mL). Total TNF-alpha production was measured by radioimmunoassay. PMNs were incubated with pH-adjusted test fluids for 30 minutes. After incubation, phagocytosis was determined by the uptake of 14C-labeled Staphylococcus aureus, oxidative burst by reduction of ferricytochrome C to ferrouscytochrome C on stimulation with phorbol myristate acetate, and enzyme release by measurement of endotoxin-stimulated bactericidal/permeability increasing factor. To study the effects of increasing glucose concentration and osmolality on PBMC and PMN functions, we compared conventional 1.5% Dianeal (1.5%D), (Baxter Healthcare Corp, Deerfield, IL) 2.5% Dianeal (2.5%D), 4.25% Dianeal (4.25%D), and control (RPMI for PBMCs and Hank's balanced salt solution for PMNs). PMNs exposed to 4.25%D exhibited an inhibition of phagocytosis, phorbol myristate acetate (PMA)-stimulated oxidative burst, and bactericidal/permeability increasing factor release compared with control, 1.5%D, or 2.5%D. To study the effects of increased osmolality when controlled for glucose concentration, we compared 1.5%D with 1.5%D in which osmolality was increased to that of 4.25%D with the addition of either sodium chloride (1.5%D+NaCl) or mannitol (1.5%D+M). High osmolality induced higher TNF-alpha production by unstimulated PBMCs and decreased TNF-alpha production by endotoxin-stimulated PBMCs. PMN functions were also inhibited by high osmolality. To study the effects of increased glucose concentration when controlled for osmolality, we compared 4.25%D with 1.5%D+NaCl and 1.5%D+M. High glucose concentration induced an increase in TNF-alpha production by unstimulated PBMCs, a decrease in TNF-alpha production by endotoxin-stimulated PBMCs, and an inhibition of PMN functions. Finally, to investigate the effects of heat sterilization, we compared 4.25%D (heat sterilized) to a filter-sterilized 4.25%D (4.25%D-F). The filter-sterilized fluid induced less changes in PBMC and PMN functions compared with the heat-sterilized fluid. These data suggest that the high glucose concentration, high osmolality, and heat sterilization of peritoneal dialysis fluids adversely affect PBMC and PMN functions. These effects could predispose continuous ambulatory peritoneal dialysis patients to peritonitis, compromise host defense during infection, and jeopardize long-term survival of the peritoneal membrane.

Biocompatible Materials↗

PubMed1998

New polyether sulfone dialyzers attenuate passage of cytokine-inducing substances from pseudomonas aeruginosa contaminated dialysate.

The use of bicarbonate dialysate and high-flux and reprocessed dialyzers has raised concerns about the reverse transfer of dialysate contaminants into the blood compartment. This in vitro study was performed to investigate the reverse transfer of soluble Pseudomonas aeruginosa bacterial products across a polyether sulfone (PES), a newly developed synthetic polymer dialyzer. In vitro dialysis was carried out at 37 degreesC in a closed countercurrent recirculating loop dialysis circuit with a new PES dialyzer. An equal mixture of heparinized whole blood (from healthy volunteers) with pyrogen-free tissue culture medium was circulated in the blood compartment, and bicarbonate dialysate was circulated in the dialysate compartment. After 15 min of dialysis, the dialysate was challenged sequentially with 10(-4), 10(-3), and 10(-2) dilutions of a P. aeruginosa culture supernatant. 1-ml samples were drawn from the blood compartment 5 and 15 min after each challenge and incubated upright at 37 degrees C. At the end of 24 h, Triton X-100 was added, in order to extract total interleukin (IL) 6 and IL-8 production by the whole-blood mixture. These cytokines were measured by electrochemiluminescence assays. At dilutions of 10(-4) and 10(-3), the reverse transfer of soluble bacterial products across the dialyzer was negligible. Five and 15 min after contaminating the dialysate with the highest concentration (10(-2) dilution), the increase in IL-6 production was 239 +/- 170% (p = 0.06) and 886 +/- 444% (p = 0.02), respectively. However, comparing the IL-6-inducing potency of the 10(-2) bacterial supernatant dilution to the spontaneous IL-6 production in the blood compartment during dialysis with the same dilution of dialysate contaminant, there was a dramatic reduction in IL-6 production by 94 and 89% at 5 and 15 min, respectively. Similarly, 5 and 15 min after contaminating the dialysate with the 10(-2) dilution, the increase in IL-8 production was 357 +/- 147% (p = 0.07) and 630 +/- 229% (p = 0.04), respectively. However, comparing the IL-8-inducing potency of the 10(-2) bacterial supernatant dilution to the spontaneous IL-8 production in the blood compartment during dialysis with the same dilution of dialysate contaminant, there was a dramatic reduction in IL-8 production by 93 and 92% at 5 and 15 min, respectively. These results demonstrate that PES dialyzers markedly attenuate passage of cytokine-inducing substances from contaminated dialysate, using a method that detects the entire cytokine synthetic output in the blood compartment.

Bacteriological Techniques↗

PubMed1997

Effect of two-chambered bicarbonate lactate-buffered peritoneal dialysis fluids on peripheral blood mononuclear cell and polymorphonuclear cell function in vitro.

Low pH, high osmolality, increasing glucose concentration, and glucose degradation products (GDP) formed during heat sterilization of conventional peritoneal dialysis (PD) fluids have been shown to have a detrimental effect on cells involved in peritoneal host defense. The two-chambered PD fluid bag in which glucose at pH approximately 3 is separated from a bicarbonate (25 mmol/L)-lactate (15 mmol/L) buffer during heat sterilization permits PD fluids with lower GDP to be delivered to the patient at neutral pH. To establish the possible benefit of two-chambered bag PD fluids on peripheral blood mononuclear cell (PBMC) and polymorphonuclear (PMN) cell function, we compared conventional 1.5% Dianeal (1.5%D) with 1.5% two-chambered bag bicarbonate-lactate (1.5%D-B), and conventional 4.25% Dianeal (4.25%D) with 4.25% two-chambered bag bicarbonate-lactate (4.25%D-B). Furthermore, to study the effect of the sterilization process on PBMC and PMN function, we compared filter-sterilized 4.25%D (4.25%D-F) with 4.25%D and 4.25%D-B. PBMC were harvested by Ficoll-Hypaque separation, and 2.5 x 10(6) cells in RPMI were incubated with an equal volume of the test fluids for 4 hours, pelleted, and resuspended in RPMI containing 10 ng endotoxin for a further 20 hours. Tumor necrosis factor alpha (TNF-alpha) production by endotoxin-stimulated PBMC was not significantly different (P = 0.10) between 1.5%D-B and 1.5%D, but was significantly higher (P = 0.01) with 4.25%D-B compared with 4.25%D. PBMC exposed to filter-sterilized fluid (4.25%D-F) showed significantly higher endotoxin-stimulated TNF-alpha production compared with 4.25%D (P = 0.02), but was not significantly different from 4.25%D-B (P = 0.40). PMN were harvested by Ficoll-Hypaque separation and 10 x 10(6) cells incubated with test fluids for 30 minutes. After incubation, phagocytosis (phagocytosis index) was determined by the uptake of 14C-labeled Staphylococcus aureus, oxidative burst by reduction of ferricytochrome C to ferrocytochrome C on stimulation with PMA, and enzyme release by measurement of endotoxin-stimulated bactericidal/permeability increasing protein (BPI). Bicarbonate-lactate two-chambered fluids of similar osmolality and glucose concentration conferred a significant improvement in phagocytosis (P = 0.02 for 1.5%D-B and P < 0.001 for 4.25%D-B). Oxidative burst and BPI release were significantly higher in 4.25%D-B compared with 4.25%D (P < 0.001). Filter-sterilized 4.25%D-F conferred a significant improvement in phagocytosis and oxidative burst compared with 4.25%D (P < 0.001) or 4.25%D-B (P < 0.001). Furthermore, conventional 4.25%D was associated with significantly lower BPI release compared with 4.25%D-F (P = 0.01). GDP's acetaldehyde and 5-HMF were analyzed in 4.25%D-B, 4.25%D, and 4.25%D-F. Acetaldehyde was below the lower limit (0.79 ppm) of the standard curve in 4.25%D-B and 4.25%D-F fluids but was detected (3.76 to 5.12 ppm) in all of the 4.25%D fluids. Relative levels of 5-HMF in the 4.25%D-B (0.032 to 0.041 Abs @ 284 nm) and 4.25%D (0.031 to 0.036 Abs @ 284 nm) were similar. The lowest levels (0.001 Abs @ 284 nm) were observed in the filter-sterilized 4.25%D-F. The beneficial effects of two-chambered bicarbonate lactate-buffered PD fluids on PBMC and PMN function are probably related to reduction of GDP from heat sterilization of glucose in a separate chamber at a lower pH. This improvement in biocompatibility could have a beneficial affect on peritoneal defenses.

Bicarbonates↗

PubMed1997

Necrosis and apoptosis of polymorphonuclear cells exposed to peritoneal dialysis fluids in vitro.

Conventional peritoneal dialysis (PD) fluids are known to inhibit polymorphonuclear cells (PMN) phagocytosis, oxidative burst and enzyme release. However, the relative contributions of apoptosis and/or necrosis to this dysfunction have not been examined. We investigated the effects of osmolality, glucose concentration and heat-sterilization of PD fluids on necrosis and apoptosis of PMN. Polymorphonuclear cells were isolated from 8 healthy volunteers and exposed to different PD fluids for four hours. PMN were then double-stained with Hoechst 33342 and propidium iodide to study the proportion of viable, apoptotic and necrotic cells. Transmission electron microscopy (TEM) was performed to confirm the results obtained with flow cytometry. The fluids studied were conventionally heat-sterilized 1.5% Dianeal (1.5% D), conventionally heat-sterilized 4.25% Dianeal (4.25% D), 1.5% D in which the osmolality was increased to that of 4.25% D by adding mannitol (1.5% D + M), a filter-sterilized version of 4.25% D (4.25% D-F) and a 1.1% amino acid PD fluid (AA) (Nutrineal PD4). All PD fluids had their pH equilibrated (pH = 7.4) by the addition of sodium bicarbonate. Compared to PMN exposed to culture medium, a significantly higher proportion of necrosis was observed in PMN exposed to 1.5% D (P = 0.04). The 4.25% D induced greater necrosis than 1.5% D (P = 0.001), and the 4.25% D also induced significantly more necrosis (P = 0.002) compared to 4.25% D-F. These data suggest that the consequences of heat-sterilization, rather than high glucose concentration are responsible for the necrosis observed. Indeed, the proportion of necrotic PMN with 4.25% D-F was not significantly different from 1.5% D. The 1.5% D + M and AA induced significantly more apoptosis compared to 1.5% D (P = 0.006 and P < 0.05, respectively), suggesting that apoptosis can be induced by the high osmolality of PD fluids. However, 1.5% D +/- M also induced significantly more apoptosis (P = 0.007) compared to 4.25% D-F. This suggests that the apoptosis effect is specific for the osmolyte present in PD fluids, and that mannitol and amino acids induce more apoptosis than glucose. In summary, the different non-physiological components of conventional PD fluids evaluated in this study had a differential effect on PMN survival. Heat sterilization of high glucose-containing PD fluids was associated predominantly with necrosis of PMN, and high osmolality with apoptosis.

Apoptosis↗

PubMed1994

Effect of sodium fusidate and ofloxacin on Staphylococcus aureus colonization and infection in patients on continuous ambulatory peritoneal dialysis.

The effectiveness of sodium fusidate and ofloxacin to eliminate nasal and catheter exit-site Staphylococcus aureus colonization and to prevent infections was compared in 31 patients on continuous ambulatory peritoneal dialysis (CAPD). In a prospective randomized study, 9 patients were treated with topical 2% sodium fusidate ointment applied in the anterior nares and in the pericatheter skin twice daily for 5 days; 9 subjects received oral ofloxacin 200 mg taken every 48 hours for 5 days and 13 subjects were in the control group. Treatment courses were repeated at one-month intervals. Mean duration of follow-up was 7.8 months (242 patients-month). Follow-up samples from the nares and the catheter exit-site were obtained every month from all participants to determine the presence of S. aureus. Development of S. aureus exit-site infection and peritonitis were assessed. During the study, S. aureus was recovered from 45%, 59% and 52% of the samples from the nares and/or exit-site in the sodium fusidate, ofloxacin and control groups, respectively (p = 0.13). S. aureus grew less frequently (p < 0.01) in samples from the exit-site in the sodium fusidate than in the other two groups. Eradication of nasal colonization (two negative cultures within one month) was observed in 43%, 40% and 33% of the cases in the sodium fusidate, ofloxacin and control groups, respectively (p > 0.50). The corresponding figures for exit-site eradication were 43%, 33% and 11%, respectively (p = 0.34). Twenty-four S. aureus-associated infection episodes (12 of exit-site and 12 of peritonitis) were diagnosed in 16 of the 31 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗