More HLA haploidentity in pairs of sibs with the same transcortin levels.

In 50 sibships, each comprising at least 2 male sibs, the oldest sib was paired with each of his brothers. All sibs were HLA- haplotyped and their serum transcortin level was determined. The HLA haploidentical pairs were compared with the sibpairs having no HLA haplotype in common. The odds for the haploidentical pairs of having a small difference (less than 0.07 mg per g total serum protein) in serum transcortin was nearly 4 times (3.94; P less than 0.025) greater than for the pairs of brothers having no HLA haplotype in common. This abnormal distribution in HLA haplotypes confirms our previous findings on the relation of certain HLA haplotypes with either high or low basal serum transcortin levels.

Response of transcortin and alpha 2u-globulin to turpentine-induced inflammation in the rat: influence of corticosteroids and prolactin.

Evidence is presented that (transcortin and alpha 2u-globulin react as negative acute-phase proteins in the rat. Thirty-six hours after turpentine injection, the serum concentration of these proteins showed a two- to threefold decrease. Thereafter, transcortin rapidly returned to normal values, whereas alpha 2u-globulin remained low. This reaction pattern was still present after adrenalectomy, adrenalectomy and administration of glucocorticoids, and after treatment with bromocriptine, a suppressor of prolactin secretion. It is concluded that changes in the secretion of glucocorticoids and prolactin are not required for the observed turpentine-induced decrease of transcortin and alpha 2u-globulin.

Transcortin and vitamin D-binding protein levels in mouse serum.

The influence of age, sex and strain on the serum concentration of transcortin (corticosteroid-binding globulin) and vitamin D-binding protein (DBP) in mice was investigated. The effect of age was studied in two strains, C57BL/6JPfd and BALB/cmHeAPfd. The concentration of transcortin and DBP increased with age. In young animals the concentration of each protein showed a significant strain difference, which disappeared in older mice for DBP, but not for transcortin. In 7-day-old animals, no sex difference was observed for either protein, but in older animals a clear sex difference was found for transcortin. Adult males tended to have somewhat higher levels of DBP than adult females, but this difference was significant only on day 70. The variation in transcortin and DBP levels was further investigated in a large number of mouse strains. The DBP concentration did not markedly vary among strains (5.98-9.65 mumol/l in males and 5.08-8.85 mumol/l in females). Transcortin, however, showed marked strain variations, ranging from 0.72 to 2.06 mumol/l in males and from 1.02 to 4.55 mumol/l in females and there was a significant correlation (r = 0.66, n = 26, P less than 0.001) between the mean transcortin levels in males and females of different strains. Interstrain variation was much higher than intrastrain variation or variation among related strains, suggesting that the transcortin concentration is largely controlled by genetically determined factors. There was a significant correlation (r = 0.82, n = 9, P less than 0.01) between the mean corticosterone and transcortin concentrations (measured at 21.00 h).(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo exposure to bicarbonate/lactate- and bicarbonate-buffered peritoneal dialysis fluids improves ex vivo peritoneal macrophage function.

The impact on peritoneal macrophage (PMO) function of acidic lactate-buffered (Lac-PDF [PD4]; 40 mmol/L of lactate; pH 5.2) and neutral-pH, bicarbonate-buffered (TB; 38 mmol/L of bicarbonate; pH 7. 3) and bicarbonate/lactate-buffered (TBL; 25 mmol/L of bicarbonate/15 mmol/L of lactate; pH 7.3) peritoneal dialysis fluids (PDFs) was compared during a study of continuous therapy with PD4, TB, or TBL. During a run-in phase of 6 weeks when all patients (n = 15) were treated with their regular dialysis regimen with Lac-PDF, median PMO tumor necrosis factor alpha (TNFalpha) release values were 203.6, 89.9, and 115.5 pg TNFalpha/10(6) PMO in the patients subsequently randomized to the PD4, TB, and TBL treatment groups, respectively. Median stimulated TNFalpha values (serum-treated zymosan [STZ], 10 microgram/mL) were 1,894.6, 567.3, and 554.5 pg TNFalpha/10(6) PMO in the same groups, respectively. During the trial phase of 12 weeks, when the three groups of patients (n = 5 per group) were randomized to continuous treatment with PD4, TB, or TBL, median constitutive TNFalpha release values were 204.7, 131.4, and 155.4 pg TNFalpha/10(6) PMO, respectively. Stimulated TNFalpha values (STZ, 10 microgram/mL) were 1,911, 1,832, and 1,378 pg TNFalpha/10(6) PMO in the same groups, respectively. Repeated-measures analysis of variance comparing the run-in phase with the trial phase showed that PMO TNFalpha release was significantly elevated in patients treated with both TB (P = 0.040) and TBL (P = 0.014) but not in patients treated with Lac-PDF (P = 0. 795). These data suggest that patients continuously exposed to bicarbonate- and bicarbonate/lactate-buffered PDFs might have better preserved PMO function and thus improved host defense status.

Evaluation of short-chain polypeptides as an osmotic agent in continuous ambulatory peritoneal dialysis patients.

OBJECTIVES: To assess whether dialysate containing short-chain polypeptides is well tolerated in continuous ambulatory peritoneal dialysis (CAPD) patients and to determine its effect on fluid and solute transport, plasma amino acid levels, and biochemical parameters. DESIGN: Two-treatment, two-period cross-over design. SETTING: Renal Unit, Academic Medical Center, Amsterdam and Renal Unit, University Hospital, Gent. PATIENTS: Two groups of 10 stable CAPD patients. INTERVENTION: All patients received a trial solution (1.36% glucose and 1% peptides, 381 mOsm/kg) and a control solution (2.27% glucose, 404 mOsm/kg) in randomized order. The patients were examined on four consecutive days in which two dwell periods on days 1 and 3 of either 4 (Group I) or 8 hours (Group II) were performed. RESULTS: The peptide solution was well tolerated in all patients. In addition, no differences were found in the parameters for the effective peritoneal surface area and the intrinsic permeability, implying that no irritating effect of the peptide solution was present. Net ultrafiltration was not different in Group I: -43 +/- 125 versus 86 +/- 125 mL (mean +/- SEM) and marginally lower in Group II: -94 +/- 64 versus 51 +/- 64 mL, despite the lower osmolality of the trial solution compared to the control solution. Glucose absorption was higher than the peptide absorption in all patients: Group I: 66 +/- 10% versus 57 +/- 13% (p = 0.0003); Group II: 80 +/- 5% versus 72 +/- 11% (p = 0.006). No differences in plasma amino acid profiles could be detected. CONCLUSIONS: Short-chain polypeptides are absorbed less than glucose and can be used as an osmotic agent in CAPD patients. However, longer-term studies are needed to evaluate possible additional effects of peptides on the nutritional status of CAPD patients.

Reduced glucose degradation products in bicarbonate/lactate-buffered peritoneal dialysis solutions produced in two-chambered bags.

OBJECTIVES: The aims of the current study were: (1) to determine the effects of peritoneal dialysis (PD) solutions at different glucose concentrations on the growth of cultured cells; (2) to determine whether a bicarbonate/lactate-based solution, as a result of the configuration of its components during heat sterilization in a two-chambered bag, was lower in glucose degradation products than a corresponding lactate-based PD solution; and (3) to determine whether lower glucose degradation corresponded to a decreased inhibition of cell growth. DESIGN: Growth inhibition of cells exposed to lactate-based PD solutions at three different glucose concentrations was determined. Bicarbonate/lactate-based and lactate-based solutions at high glucose concentration (3.86%) were further analyzed for presence of glucose degradation products and inhibition of cell growth. METHODS: Cell growth was determined by neutral red uptake, measured by optical density at 540 nm. Glucose degradation to acetaldehyde or fructose was determined by gas chromatography-mass spectroscopy and high-performance liquid chromatography. RESULTS: Only 3.86% glucose lactate-based PD solution caused significant inhibition of cell growth (p < 0.05). The heat-sterilized, bicarbonate/dlactate-based solution (3.86% glucose) had lower levels of fructose and acetaldehyde than a conventional heat-sterilized, lactate-based solution with the same glucose concentration. Growth of cultured cells exposed to the bicarbonate/lactate-based solution was significantly improved (p < 0.05) over growth in the conventional solution. CONCLUSIONS: The bicarbonate/lactate-based solutions, manufactured and heat-sterilized in two-chambered bags, were lower in glucose degradation products than that corresponding lactate-based PD solutions, and demonstrated improved in vitro biocompatibility as measured by the growth of cultured cells.

Clinical evaluation of a peritoneal dialysis solution with 33 mmol/L bicarbonate.

OBJECTIVE: To evaluate the efficacy and safety of a new peritoneal dialysis solution with 33 mmol/L bicarbonate. DESIGN: In an acute, prospective, randomized cross-over study, 8 patients were randomized in two groups of 4. On the first study day, the first group performed two consecutive 4-hour exchanges with a dialysis solution containing 35 mmol/L lactate: the first exchange with 13.6 g/L and the second with 38.6 g/L dextrose. On the second study day, the same type of exchanges were performed with bicarbonate. The second group underwent the same treatment, but used bicarbonate solutions on the first day and control solutions on the second study day. Thirty-three patients participated in a 2-month prospective and randomized study. After a 4-week baseline period using solutions containing 40 mmol/L lactate, the patients were dialyzed with either 33 mmol/L bicarbonate solutions or 40 mmol/L lactate solutions. SETTING: Peritoneal dialysis units at the University Hospital of Brescia and the Niguarda Hospital of Milan, Italy. RESULTS: Acute study: Control and bicarbonate solutions had similar effects on blood chemistries and peritoneal transport. Chronic study: Mean venous bicarbonate concentrations remained unchanged in the control group (26.6-27.2 mmol/L), but decreased significantly in the bicarbonate group from 28.8 mmol/L at the start of the study to 23.0 mmol/L after 2 months of bicarbonate administration. Other biochemical parameters remained unchanged. CONCLUSION: A peritoneal dialysis solution with a bicarbonate level of 33 mmol/L does not adequately correct uremic acidosis.

Effect of bicarbonate-based dialysis solutions on intracellular pH (pHi) and TNFalpha production by peritoneal macrophages.

OBJECTIVE: To compare the effect of Dianeal and two newly-formulated bicarbonate-based peritoneal solutions on intracellular pH (pHi), tumor necrosis factor-alpha (TNFalpha) mRNA level, and TNFalpha secretion by peritoneal macrophages (PMphi). DESIGN AND MEASUREMENTS: Peritoneal macrophages were isolated from dialysates collected after overnight dwells in peritonitis-free continuous ambulatory peritoneal dialysis patients. Dialysis solutions contained 1.5% or 4.25% dextrose. HCO3 concentrations of bicarbonate-(TB) and bicarbonate/lactate-buffered (TBL) solution were 38 mM and 25 mM, respectively. TBL also contained lactate at a concentration of 15 mM. pCO2 levels were 78 mmHg and 51 mmHg, respectively. In all experiments pCO2 was carefully maintained at a stable level. The pHi was measured by spectrofluorometry in BCECF-loaded PMphi exposed to different dialysis solutions or Hank's balanced salt solution. TNFalpha levels were measured by ELISA in the supernatant of lipopolysaccharide- (LPS) stimulated PMphi after their incubation in different solutions for 15 and 30 minutes. TNFalpha mRNA was measured by reverse transcriptase polymerase chain reaction (RT-PCR) of total RNA extracted from LPS-stimulated PMphi after their incubation in different solutions for 30 minutes. beta-actin mRNA was used as the control. RESULTS: Dianeal caused a profound drop in pHi to below 6.2. Following an initial drop, pHi stabilized after 4 minutes at levels of 6.96 and 6.8 after incubation in TB and TBL, respectively. In comparison to the control solution, a fall of 11% and 21% in TNFalpha secretion was seen after incubation in TB for 15 and 30 minutes, respectively, and 15% and 26% after incubation in TBL. Under identical conditions, Dianeal (Baxter, McGaw Park, IL, U.S.A.) caused 59% and >95% suppression of TNFalpha secretion. Accordingly, TNFalpha mRNA level in PMphi was severely depressed by Dianeal but no detectable inhibition was observed following incubation for 30 minutes in TB and TBL. When dextrose concentration in TB and TBL was increased from 1.5% to 4.25%, TNFalpha secretion by PMphi was not suppressed by more than 49%, even after 30 minutes incubation. Moreover, suppression of TNFalpha mRNA levels could not be detected with TB or TBL even at high dextrose concentrations. CONCLUSIONS: In contrast to Dianeal, both bicarbonate-based solutions caused only a mild drop in pHi of PMphi. We postulate this effect to be responsible for the improved capacity of PMphi to secrete TNFalpha when incubated in bicarbonate-based solutions compared to Dianeal. Reflecting its known cytotoxicity, dextrose in high concentrations diminishes the protective effect of TB and TBL on immune function of PMphi. TBL is as effective as TB in preventing the deleterious effect of Dianeal on PMphi function.

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.

A randomized controlled trial of a bicarbonate- and a bicarbonate/lactate-containing dialysis solution in CAPD.

OBJECTIVE: To evaluate the safety and efficacy of bicarbonate- and bicarbonate/lactate-based PD fluids. DESIGN: A randomly allocated prospective controlled trial lasting eight weeks. SETTING: Five renal units in Europe. PATIENTS: Individuals who have been treated by CAPD for at least three months and who have had at least one month's therapy with 40 mmol/L lactate PD fluid. Those with recent infection, diabetes or other serious illness are excluded. Forty-seven individuals have entered the study so far. INTERVENTIONS: Patients are randomly allocated to three groups. Group 1 receive 40 mmol/L lactate dialysate, Group 2 are given 38 mmol/L bicarbonate fluid and Group 3 are tested with a 25 mmol/L bicarbonate and 15 mmol/L lactate dialysate. OUTCOME MEASURES: The primary outcome measure is the plasma bicarbonate level. Adverse events and ease of use of the two-chambered bags used by Groups 2 and 3 are also being assessed. RESULTS: To date, plasma bicarbonate levels have been the same in all treatment groups up to the end of the trial period. There are no differences in serum lactate levels. No side effects are attributable to the test fluids. The patients have managed the two-chambered bags successfully. CONCLUSION: This trial is still ongoing, but to date, neutral bicarbonate based fluids have been as effective as lactate dialysate in treating uremic acidosis.

Acidosis correction with a new 25 mmol/l bicarbonate/15 mmol/l lactate peritoneal dialysis solution.

OBJECTIVE: The aim of this study was to evaluate the effects of a combined 25 mmol/L bicarbonate/15 mmol/L lactate-based solution (Bic/Lac), compared to a 35 mmol/L lactate solution (Lac)--the most commonly used solution for patients in southern Europe--on the venous plasma bicarbonate level in patients treated with continuous ambulatory peritoneal dialysis (CAPD). DESIGN: This was a randomized, parallel, controlled, open-label study, with patients studied for a period of 3 months preceded by a 1-month baseline and followed by a 1-month follow-up. Patients used the 35 mmol/L lactate solution during baseline and follow-up periods. SETTING: Four Spanish nephrology centers. PATIENTS: Thirty-one (20 Bic/Lac, 11 Lac) well-dialyzed (creatinine clearance > 55 L/week/1.73 m2 body surface area) CAPD patients. INTERVENTIONS: Blood samples were taken for biochemistry tests at all visits. A physical examination was completed at baseline and month 3, and a medical update was completed after 1, 2, and 3 months, and at the follow-up visit. Adverse-event monitoring and notation of prescription changes were carried out continuously. MAIN OUTCOME MEASURE: Effect on venous plasma bicarbonate level. RESULTS: Venous plasma bicarbonate rose by 3.1 mmol/L (confidence intervals 1.6-4.8),from a baseline level of 23.0 mmol/L during the treatment period in those patients treated with Bic/Lac (p < 0.05 vs Lac). The number of acidotic patients (venous plasma bicarbonate < 24 mmol/L) was statistically significantly reduced at every treatment period visit in the Bic/Lac group (p < 0.05). There were no adverse findings with respect to vital signs, physical examination, or clinical symptoms, apart from one death in the control group. CONCLUSIONS: The new Bic/Lac solution allowed better correction of acid-base status than the lactate solution.

Comparison of in vitro AGE formation between standard PD fluid and a novel bicarbonate/lactate formulation.

Peritoneal advanced glycation end-product (AGE) formation may be accelerated by glucose degradation products produced as a consequence of heat sterilization of peritoneal dialysis (PD) fluid. The formation of these degradation products is reduced if the glucose is separated from the buffers during heat sterilization. This pilot study compared in vitro AGE formation in PD fluid (1.36% and 3.86% glucose) heat sterilized in a two-compartment bag (bicarbonate/lactate buffer) with that in a standard, single-compartment bag (lactate buffer, Dianeal). Peritoneal dialysis fluids were incubated with human serum albumin (HSA, 1 g/L), as a model protein, at 37 degrees C for 0, 5, and 20 days. Formation of AGEs was assessed by measuring fluorescence at each time point. Advanced glycation end-product formation was greater in lactate PD fluid compared with bicarbonate/lactate PD fluid of equivalent glucose strength. Advanced glycation end-product formation in the lactate PD fluid containing 1.36% glucose was comparable to that in the bicarbonate/lactate PD fluid containing 3.86% glucose. The rate of increase in fluorescence per day was greater in the first 5 days of incubation than in the subsequent 15 days. These results are compatible with the presence of greater amounts of glucose-degradation products in the standard single-compartment bag resulting in enhanced AGE formation.

Serum transcortin levels in patients with chronic hemodialysis.

Patients with renal insufficiency who are hemodialyzed 3 times a week either through a cuprophane membrane or through a polyacrylonitrile (PAN) membrane have the same transcortin and cortisol levels as patients with renal insufficiency who are not dialyzed. Moreover, hemodialysis did not influence acutely the latter transcortin levels.

Phylogenetic study of transcortin using monoclonal antibodies.

We produced monoclonal antibodies that recognise three distinct epitopes of human transcortin. These epitopes are present on transcortin of humans with normal and altered transcortin levels, as well as on a variant with lower affinity for cortisol. One epitope is present on transcortin of Old World Monkeys and apes, the others are only present on transcortin of apes. The epitopes are not present on transcortin of other species. These results indicate that human transcortin contains a highly evolved and a more conserved part.

Use of monoclonal antibodies in a radioimmunoassay for human transcortin.

We describe the production of monoclonal antibodies to human transcortin and their use in a radioimmunoassay (RIA). A high-affinity antibody (Ka = 4 X 10(10) L/mol) made possible a sensitive RIA for transcortin (detection limit = 0.23 ng per tube), whereas use of an antibody of moderate affinity (Ka = 5 X 10(8) L/mol) was more suitable for the routine measurement of transcortin in serum, only a 25-fold dilution of the sample being required instead of 1500-fold. The correlation was good between both RIAs (r = 0.959) and between each of the RIAs and radial immunodiffusion (r = 0.955 and 0.976 for the methods with high- and low-affinity antibody, respectively). Although monoclonal antibodies were used in the RIAs and polyclonal ones in the radial immunodiffusion procedure, similar values were obtained by all techniques.