In vitro evaluation and targeting of E. coli internalized by endothelial cells using albumin microspheres loaded with gentamicin.

The purpose of this study was to evaluate the use of microencapsulated form of gentamicin and the traditional solution form for its intracellular bactericidal effect. Bovine serumalbumin (BSA) microspheres loaded with gentamicin were prepared by using Mini Spray Dryer. Human microvascular endothelial cells (HMECs) were exposed to increasing concentrations of Escherichia coli leading to internalization of E. coli. The internalized bacteria were targeted using either the microencapsulated or the solution form of gentamicin. The treatment groups using gentamicin solution form and microsphere form showed almost 46% and 86% inhibition in the growth of the internalized bacteria, respectively.

Microspheres containing neutralizing antibodies to tumor necrosis factor-alpha and interleukin-1 beta protect rats from Staphylococcus aureus-induced peritonitis.

Previous studies using microencapsulated neutralizing antibodies (NA) to tumor necrosis factor (TNF) and interleukin-1 (IL-1) in combination with gentamicin have demonstrated improved survival in a peritonitis model of gram-negative septic shock. Microencapsulation has been shown to improve the effectiveness of NA by delivering them intracellularly, taking advantage of the natural phagocytic activity of the macrophage. It is the purpose of this study to see if microencapsulated NA to TNF and IL-1 in combination with vancomycin can improve survival compared with NA in solution in Staphlococcus aureus-induced septic shock. Groups of 10 rats received the following treatments: (1) S. aureus plus no treatment, (2) S. aureus plus blank microspheres, (3) S. aureus plus vancomycin, (4) S. aureus plus a microsphere form of NA and vancomycin, (5) S. aureus plus a solution form of NA and vancomycin, (6) S. aureus plus a microsphere form of NA, and (7) S. aureus plus a solution form of NA. Survival was monitored for 5 days, and plasma TNF and IL-1 levels were measured for 48 h after S. aureus administration. All (100%) animals that received the microsphere form of NA plus vancomycin, 20%-70% of the animals that received the microsphere form of NA alone, and 20% of the animals that received antibiotics alone survived for 5 days or more. None of the animals in the no treatment group or blank microsphere treatment group and only 10% of the animals in the solution form of NA plus or minus vancomycin group survived for more than 5 days. Plasma TNF and IL-1 levels were significantly increased after S. aureus treatment. Simultaneous and delayed treatment with the microsphere form of NA plus or minus vancomycin significantly reduced TNF and IL-1 levels, and the solution form of NA significantly reduced only TNF levels after immediate treatment. The survival rate was higher in animals with lower TNF levels and IL-1 levels. The results demonstrate that the microsphere form of cytokine NA is 100% effective in combination with vancomycin in protecting rats from S. aureus-induced peritonitis. The microsphere form was also more efficient in attenuating both TNF and IL-1 levels.

Prevention of lethality and suppression of proinflammatory cytokines in experimental septic shock by microencapsulated CNI-1493.

CNI-1493, a newly developed, water-soluble tetravalent guanylhydrazone, is a powerful inhibitor of tumor necrosis factor (TNF) and interleukin-1 (IL-1) synthesis. Microencapsulation of drugs into microcapsules that target macrophages has improved the effectiveness of both TNF and IL-1 neutralizing antibodies in experimental models of septic shock. It is the purpose of this study to determine if microencapsulation of CNI-1493 will improve cytokine inhibition. CNI-1493 was microencapsulated using albumin into 1 microm spheres. Comparable amounts of CNI-1493 in solution and in microencapsulated form were added to 1 ml aliquots of whole blood along with 100 ng of endotoxin. TNF and IL-1 were measured by ELISA. Microencapsulated CNI-1493 was also given to rats with endotoxic shock (15 mg/kg Escherichia coli endotoxin) and rats with peritonitis induced by peritoneally injecting 10(10) CFU E. coli. Equivalent amounts of encapsulated and solution CN I-493 were given intravenously. Endotoxin 15 mg/kg was also given to rats 6 and 24 h after a dose of encapsulated CNI-1493 to determine the duration of action of encapsulated drug. The microencapsulated CNI-1493 produced significantly greater inhibition of TNF and IL-1 at all doses in the whole blood model. There was significantly improved survival and cytokine inhibition in the endotoxic shock model as well as the peritonitis model in rats treated with microencapsulated CNI-1493. There was also 83% survival in rats given endotoxin 24 h after a dose of encapsulated CNI-1493. From these data, we conclude that CNI-1493 is a potent inhibitor of cytokine production and is greatly potentiated by microencapsulation, which transports the drug to macrophages.

Evaluation of microspheres containing cytokine neutralizing antibodies in endotoxemia.

Albumin microspheres are efficient carriers for delivering therapeutic agents to macrophages. In response to endotoxin, macrophages release tumor necrosis factor alpha (TNF alpha) and interleukin-1-beta (IL-1 beta). Blocking the effects of TNF alpha and IL-1 beta decreased lethality due to endotoxin-induced shock. In this study, we compared the efficacy of the microsphere form of TNF alpha and/or IL-1 beta neutralizing antibodies (NAs) with the free form of TNF alpha and/or IL-1 beta NA in preventing lethality due to endotoxemia and evaluated the duration of blockade by the microsphere form of TNF alpha and/or IL-1 beta NA on endotoxin-induced cytokine release. The results indicate that the microsphere form of TNF alpha and/or IL-1 beta NA protected 80% of the rats from lethal endotoxemia, while none of the rats that received the free from of TNF beta and/or IL-1 beta NA survived longer than 48 hr. The microsphere form of TNF alpha and/or IL-1 beta NA attenuated endotoxin-induced cytokine release more potently than the free form of TNF alpha and/or IL-1 beta NA in vivo. In vitro, the microsphere form of TNF alpha and/or IL-1 beta NA blocked endotoxin-induced cytokine release for at least 24 hr. Higher efficacy of the microsphere form of NA in reducing mortality and blocking cytokine release makes it more therapeutically advantageous than the free form of NA in the treatment of lethal endotoxemia.

Macrophage depletion by albumin microencapsulated clodronate: attenuation of cytokine release in macrophage-dependent glomerulonephritis.

A macrophage plays an important role in mediating the inflammatory response. Cytokines released by activated macrophages contribute to inflammation in glomerulonephritis (GN). Clodronate, a biphosphonate, causes macrophage depletion when administered in an encapsulated form in liposomes. We used albumin as the polymer matrix to microencapsulate clodronate to the microspheres (MS) in the 1-micron size range. The purpose of this study was to (a) determine macrophage depletion by clodronate MS, (b) determine the effect of clodronate MS on endotoxin-induced cytokine release in vitro, and (c) assess the effect of clodronate MS on macrophage infiltration in experimental antiglomerular basement membrane nephritis. Macrophage depletion by clodronate MS was assessed by staining for the EDI marker. The results indicate greater than 95% depletion of macrophages from the spleen, liver, kidney, and blood. In the whole blood model, clodronate MS attenuated endotoxin-induced tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) release, and the attenuation by the microencapsulated form of clodronate was also more effective than the free (solution) form of clodronate. Macrophage infiltration into the glomerulus in experimental GN was also blocked very effectively by pretreatment with clodronate MS. In conclusion, macrophage depletion by clodronate MS may be beneficial in reducing cytokine release and renal damage in GN.

Targeting macrophages with microspheres containing cytokine-neutralizing antibodies prevents lethality in gram-negative peritonitis.

Macrophages release proinflammatory cytokines in response to infection that play a critical role in the pathophysiology of septic shock. We propose that targeting cytokine-neutralizing antibodies using albumin microspheres to macrophages will be more beneficial than the soluble form in reducing mortality related to peritonitis. In this study, we compared the distribution pattern of microspheres in infected and noninfected animals, evaluated the amount of microsphere taken up by peritoneal macrophages in vitro, and compared the efficacy of soluble and microsphere forms of cytokine-neutralizing antibodies in preventing lethality caused by Escherichia coli-induced peritonitis. The results indicate that twice the amount of microspheres accumulates near the site of infection (the peritoneal cavity), and 70% of the microspheres exposed to peritoneal macrophages were phagocytosed in 1 h. Treatment with the microsphere form of cytokine-neutralizing antibodies was more efficacious than using the soluble form in preventing lethality induced by E. coli. Immediate treatment was more efficacious than delayed treatment in the absence of gentamicin, whereas immediate and delayed treatment were equally efficacious in the presence of gentamicin. The combination of microspheres containing neutralizing antibodies to tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) protected 100% of the animals, whereas either one alone protected only 60%-90% of the animals from lethality caused by E. coli-induced peritonitis. In conclusion, the microsphere form of neutralizing antibodies to TNF-alpha IL-1beta may be an effective therapeutic agent in the treatment of septic shock caused by peritonitis.

In vitro comparison of cytokine release from antithymocyte serum and OKT3. Inhibition with soluble and microencapsulated neutralizing antibodies.

Antilymphocyte antibodies are widely used to prevent and treat rejection after organ transplantation. Induction of cytokine release is implicated in the side effects produced by these antibodies. In this study, cytokine release induced by OKT3 was compared with antithymocyte serum (ATS) using an in vitro whole blood model. The efficacy of the microsphere form of cytokine-neutralizing antibodies to attenuate OKT3 and ATS-induced cytokine release was compared with the soluble form of cytokine-neutralizing antibodies. OKT3-induced significantly higher amounts of tumor necrosis factor-alpha and interleukin 1 beta levels compared with ATS. The microsphere form of tumor necrosis factor-alpha and interleukin 1 beta neutralizing antibodies attenuated OKT3 and ATS-induced cytokine release much more efficiently compared with the soluble form. The results suggest that the severity of the side effects is related to the amount of cytokine release. Microencapsulated cytokine-neutralizing antibodies might be a better therapeutic agent than the soluble form of cytokine-neutralizing antibodies in the treatment of side effects induced by antilymphocyte antibodies.

Potency of endotoxin from bicarbonate dialysate compared with endotoxins from Escherichia coli and Shigella flexneri.

Endotoxin is a potent activator of the complement system and other host immunoregulators, including the cytokines, tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6. In this study, the potency of an endotoxin from bicarbonate dialysate was compared with endotoxins from two enteric microorganisms, Shigella flexneri and Escherichia coli. Endotoxin concentrations were standardized for the three endotoxins by use of the Limulus amebocyte lysate turbidimetric assay. Endotoxin potency was assessed by the comparative plasma concentrations of tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 after an in vitro whole-blood challenge by each type of endotoxin. Blood collected from 10 hemodialysis patients was spiked with 0.1, 1, and 10 ng/mL of E. coli and Shigella endotoxin and with 1 and 10 ng/mL of bicarbonate dialysate endotoxin. After incubation, plasma was separated and frozen at -70 degrees C until assayed for cytokine concentrations. Dialysate endotoxin was found to be 10 to 100 times less potent than E. coli and Shigella endotoxins. It was concluded that there are significant differences in the potency of endotoxins from different strains of bacteria and that these differences should be noted when designing or evaluating studies on the clinical effects of endotoxins in hemodialysis settings.

Prolongation of murine cardiac allograft survival by microspheres containing TNF alpha and IL1-beta neutralizing antibodies.

Efficient delivery of therapeutic agents to a critical microenvironment may increase the efficacy of drugs used to modulate the allograft rejection response. This study demonstrates the ability of the combination of microspheres containing neutralizing anti-TNF alpha and anti-IL1-beta antibodies to significantly prolong murine cardiac allograft survival. These results suggest that the microsphere technique is an efficacious method to target antibody delivery to prolong allograft survival.

The effect of uremia on tumor necrosis factor-alpha release after an in vitro whole-blood endotoxin challenge.

Uremia has been associated with immunologic aberrations, including anergy, increased susceptibility to infections, and reduced phagocytic activity of polymorphonuclear leukocytes. In this study, cytokine release in uremic and nonuremic blood after in vitro endotoxin stimulation was studied. Blood from nonuremic controls, chronic renal failure patients not on dialysis, and chronic hemodialysis patients predialysis and postdialysis was spiked with 10 ng/mL of Escherichia coli endotoxin and incubated for 2 and 26 h. Plasma tumor necrosis factor-alpha (TNF alpha) concentrations were determined by ELISA after each incubation period. To further study which uremic blood component may be responsible for enhanced release of TNF alpha, plasma and cellular components of chronic renal failure patients and controls were switched and then given an in vitro endotoxin stimulation (1 ng/mL). It was found that (1) TNF alpha release is enhanced by uremia and is exacerbated with progressive declines in renal function, (2) enhanced TNF alpha release is related to a blood cellular phenomenon induced by uremia, and (3) enhanced TNF alpha release in hemodialysis patients is associated with a prolonged stimulation and/or reduced plasma elimination of TNF alpha.

Normalization of uremic acidosis in hemodialysis patients with a high bicarbonate dialysate.

Uremic acidosis accompanies chronic renal failure in hemodialysis patients because of a retention of nonvolatile acids. Standard bicarbonate (39 mEq/L) and acetate (38 mEq/L) dialysates do not completely correct the acidosis. The acid-base and biochemical effect of a high-bicarbonate (42 mEq/L) dialysate was evaluated in 38 patients during high-efficiency and high-flux dialysis over 12 wk. All patients were dialyzed on standard bicarbonate dialysate before the study and for 8 wk after the study. In order to monitor potential excessive alkalosis, predialysis and postdialysis arterial blood gases were measured in seven patients who initially had a normal predialysis pH. Serum chemistries revealed no significant changes in predialysis BUN, calcium, ionized calcium, or phosphorus during the 12-wk study. There was no change in postdialysis ionized calcium or phosphorus. Predialysis and postdialysis serum total CO2 (STCO2) increased over the 12-wk study (P < 0.0001). By week 12, 75% of the hemodialysis patients had an STCO2 > 23 mEq/L and no patient had an STCO2 > 30 mEq/L predialysis. After the 8-wk washout, all chemistries were no different from prestudy concentrations. Predialysis blood gases in seven patients with normal predialysis HCO3 revealed a significant increase (P < 0.009) in PCO2 and HCO3 over the 12-wk study; predialysis pH and PO2 did not change. There was no significant change in postdialysis blood gases. It was concluded that: (1) a high-bicarbonate dialysate corrects predialysis acidosis in 75% of hemodialysis patients without causing progressive alkalemia, hypoxia, or hypercarbia; and (2) predialysis BUN, calcium, ionized calcium, and phosphorus are unaffected by high-bicarbonate dialysate.

Cytokine kinetics in an in vitro whole blood model following an endotoxin challenge.

Whole blood and peripheral blood mononuclear cell (PBMC) culture models have been used to study cytokine stimulation and release in vitro. In this study, we characterize the kinetics of the interleukins (IL-1 beta), (IL-6), (IL-8), and tumor necrosis factor-alpha (TNF-alpha) following an endotoxin (ET) challenge using our in vitro whole blood model. Whole blood samples from 10 healthy volunteers were studied. All cytokines were measured by enzyme-linked immunosorbent assay. Peak concentrations of TNF-alpha occurred 2 h after ET challenge followed by a rapid decline in free plasma TNF-alpha concentration (half-life 18.2 min). IL-1 beta was not significantly elevated until 4 h after ET challenge. IL-8 was elevated 1 h after ET challenge. IL-6 concentration exhibited a biphasic peak occurring at 6 and 74 h after ET challenge. We conclude that (1) our whole blood in vitro model produces cytokine release kinetics similar to those reported in vivo, and (2) the presence of either binding proteins or cellular metabolism of TNF-alpha in whole blood produces a similar plasma half-life to that observed in vivo.

A prospective study of pyrogenic reactions in hemodialysis patients using bicarbonate dialysis fluids filtered to remove bacteria and endotoxin.

Pyrogenic reactions (PR) are a well-recognized complication of hemodialysis and have been associated with dialyzer reuse, high-flux dialysis, and bicarbonate dialysate. However, the roles of bacteria and endotoxin in dialysate for producing PR are not well defined. To determine the effect of removing most bacteria and endotoxin from the dialysate on the incidence of PR, a cohort of chronic hemodialysis patients receiving high-flux, high-efficiency, or conventional hemodialysis at three centers with bicarbonate dialysis fluids that had been filtered with a polysulfone high-flux hemodialyzer was prospectively studied. Unfiltered bicarbonate concentrate had median bacterial and endotoxin concentrations of 479,000 CFU/mL and 39,800 pg/mL, respectively. After filtration of the bicarbonate concentrate at the central proportioner, dialysate had a median 9.2 CFU/mL of bacteria and 17.8 pg/mL of endotoxin. Dialysate filtered at individual proportioning dialysis machines had a median 0.001 CFU/mL of bacteria and 0.19 pg/mL of endotoxin. Nine PR were identified among 303 patients after 28,007 hemodialysis treatments (0.3 PR/1,000 treatments). The rate of PR was similar for the three hemodialysis treatment modalities and for first-use compared with reused dialyzers. Although the PR rate in this study was lower (P = 0.046) than the PR rate of a previous study with unfiltered dialysis fluids (0.7 PR/1,000 treatments), it represents a difference of only 10 PR in over 28,000 treatments. It was concluded that filtration of hemodialysis fluids is efficacious in removing bacterial and endotoxin contamination and can result in a lower incidence of PR in patients receiving high-flux, high-efficiency, or conventional hemodialysis.

The effects of calcium carbonate as the sole phosphate binder in combination with low calcium dialysate and calcitriol therapy in chronic hemodialysis patients.

Alternative phosphate binders, such as CaCO3, have been shown to be effective in the control of phosphate (P) retention in hemodialysis patients (HDP). Additionally, both oral (POC) and iv (IVC) calcitriol are purported to be of benefit in the control of secondary hyperparathyroidism. This investigation was undertaken to determine: (1) the effectiveness of CaCO3 as the sole P binder in combination with low (2.5 mEq/L) Ca dialysate; (2) the effects of discontinuing Al(OH)3 binders on both unstimulated and stimulated Al concentrations; and (3) the comparative parathyroid hormone (PTH) response to both POC and IVC in a large group of hemodialysis patients. One hundred ninety-four HDP completed part 1 of the study where CaCO3 was substituted for Al(OH)3 as the sole P binder for 6 months. A cohort of 49 HDP was given desferoximine (40 mg/kg) initially and 10 months after using CaCO3. In part 2, 54 HDP were given POC and 97 HDP were given IVC in dosages of 0.25 to 0.5 micrograms/day and 1.5 to 6.0 micrograms/wk, respectively, for an additional 6 months. In part 1, Ca and P were not different from baseline values observed with Al(OH)3 therapy. Ionized Ca increased (P < 0.05) and PTH decreased (P < 0.001) during CaCO3 therapy without vitamin D. In part 2, PTH declined 23% with IVC and was unchanged with POC in equivalent dosages (P < 0.05) at 3 months. By 6 months, PTH declined a total of 54% with IVC and was unchanged with POC. Ca, ionized Ca, P, and serum calcitriol were greater (P < 0.05) in the IVC group at 6 months. Serum Al concentrations for the entire 194 HDP fell 65% (P < 0.0001) over 12 months. In the 49 HDP cohort, serum Al fell 43.6% (P < 0.001) and stimulated Al concentrations decreased 68.7% (P < 0.0001) after 10 months. We conclude that: (1) CaCO3 is as effective as Al(OH)3 in controlling P, (2) a small decrease in PTH is observed with CaCO3 alone, (3) serologic evidence of Al excess is virtually eliminated, (4) PTH suppression with IVC is superior to that seen with POC in equivalent doses.

Bacteria and endotoxin removal from bicarbonate dialysis fluids for use in conventional, high-efficiency, and high-flux hemodialysis.

The use of bicarbonate-based dialysis fluids in hemodialysis centers in the United States has increased with the advent of high-efficiency and high-flux hemodialysis. However, bicarbonate dialysis fluids can support rapid bacterial growth and high endotoxin concentrations. This study determined the efficacy of an ultrafiltration device in reducing the bacterial and endotoxin concentrations in bicarbonate dialysis fluids. A polysulfone hollow fiber dialyzer was used to ultrafilter bicarbonate concentrate before entering the central proportioner and bicarbonate dialysate after exiting the proportioner in single patient dialysis machines. Pre- and post-ultrafilter samples were collected for bacterial and endotoxin assays over 10 months. Ultrafiltration of bicarbonate concentrate reduced bacterial and endotoxin concentrations from 288,330 colony forming units (CFU)/ml and 42,804 pg/ml to 0.47 CFU/ml and 109 pg/ml, respectively. Ultrafiltration of the dialysate in single patient systems decreased bacterial and endotoxin concentrations from 15,889 CFU/ml and 1,746 pg/ml to 0.003 CFU/ml and 0.109 pg/ml, respectively. These results demonstrate that ultrafiltration of bicarbonate dialysis fluids is effective in reducing bacterial and endotoxin contamination inherently associated with the use of bicarbonate-based dialysates.

Pyrogenic reactions in patients receiving conventional, high-efficiency, or high-flux hemodialysis treatments with bicarbonate dialysate containing high concentrations of bacteria and endotoxin.

High-efficiency (HE) and high-flux (HF) hemodialysis are becoming increasingly popular methods for treating patients with chronic renal failure because they reduce the time required for dialysis treatment. HF and HE dialyzers require bicarbonate dialysate, often prepared from concentrates that can support bacterial growth with endotoxin production. There is a concern that endotoxins or bacteria may cross or interact at the membranes of these dialyzers, triggering the release of endogenous pyrogens (cytokines) by peripheral blood mononuclear cells to cause pyrogenic reactions (PR). To determine the incidence of PR and to examine the association between PR and levels of bacteria and endotoxin in dialysate, a cohort of patients receiving conventional, HE, or HF hemodialysis with bicarbonate dialysate and reprocessed dialyzers at three dialysis centers during a 12-month period was studied prospectively. All dialyzers underwent a test of membrane integrity before use. A total of 19 PR were identified among 18 patients in 26,877 hemodialysis treatments (0.7 PR/1,000 treatments). There was no significant difference in PR rates by treatment modality: conventional, 0.5 per 1,000 (7 PR/13,123 treatments) versus HE, 0.9 per 1,000 (9 PR/11,345) versus HF, 1.2 per 1,000 (3 PR/2,409) (P = 0.21; chi 2 test). Throughout the study period, bacterial counts for dialysate at each center significantly exceeded the Association for the Advancement of Medical Instrumentation's (AAMI) microbiologic standards for dialysate of less than 2,000 CFU/mL (mean, 19,000 CFU/mL), but water used in the reuse of dialyzers tested less than 200 CFU/mL.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of plasma interleukin-1 beta or tumor necrosis factor-alpha elevation during unfavorable hemodialysis conditions.

Plasma interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) were determined by ELISA in 17 healthy controls, 23 HD patients, 10 continuous ambulatory peritoneal dialysis patients, and 15 chronic renal failure patients, as well as in 2 HD patients experiencing pyrogenic reactions. Another group of 10 chronic HD patients were dialyzed for 2.5 h, 5 with first-use Cuprophan membranes and 5 with first-use high-flux cellulose triacetate membranes. The mean bacterial and endotoxin concentrations of the dialysate used for HD treatments during the study period were 18,440 +/- 530 CFU/mL (mean +/- SEM) and 976 +/- 205 pg/mL, respectively. Blood specimens were obtained intradialysis and postdialysis for cytokine assay and were incubated to augment cytokine production. There was no difference in plasma IL-1 beta or TNF-alpha concentrations among the healthy controls, continuous ambulatory peritoneal dialysis patients, chronic renal failure patients, or HD patients. Neither cytokine increased significantly during or after HD. Two patients experiencing pyrogenic reactions had plasma TNF-alpha concentrations of 537 and 413 pg/mL, compared with matched controls of 6 and 0 pg/mL. Il-1 beta concentration did not differ from controls. We conclude that: (1) plasma IL-1 beta and TNF-alpha are not chronically elevated in chronic renal failure, continuous ambulatory peritoneal dialysis, or HD patients; (2) HD with new Cuprophan or cellulose triacetate membranes and high concentrations of dialysate endotoxin and bacteria does not cause elevation of circulating IL-1 beta or TNF-alpha; and (3) pyrogenic reactions might be mediated by TNF-alpha.

Enhanced release of TNF-alpha, but not IL-1 beta, from uremic blood after endotoxin stimulation.

Aberrant immunologic host defenses associated with uremia may be a cause of the high incidence of sepsis in chronic hemodialysis (CHD) patients. This investigation determined the cytokine response of blood from five nondialyzed chronic renal failure (CRF) patients, five CHD patients, and five healthy controls (HC) after in vitro stimulation with 1 ng/ml Escherichia coli 0113 endotoxin. Concentrations of the cytokines TNF-alpha and IL-1 beta were determined by ELISA and were similar in all baseline and unspiked samples. TNF-alpha concentrations in CRF and CHD spiked samples were similar to each other but significantly greater (p less than 0.01) than in HC spiked samples. IL-1 beta concentrations in CRF, CHD, and HC-spiked samples were not significantly different. We conclude that CRF and CHD patients have enhanced TNF-alpha response, which may be related to uremia and not dialysis-related factors. Uremia does not potentiate IL-1 beta release.

An economical new process for incenter bicarbonate dialysate production: comparison with acetate in a large dialysis population.

It is generally agreed that bicarbonate dialysate is preferable to acetate dialysate, but the major limiting factors of high cost and technical difficulty in maintaining its stability for prolonged periods preclude its widespread use. The procedure developed by the authors stabilizes bicarbonate dialysate for up to 4 days, rendering bicarbonate dialysate feasible for routine out-patient use. HCO3 dialysate is produced in our dialysis unit after an initial investment of $10,000.00, at a cost per 4-h treatment of $1.22 at a dialysate flow of 500 cc/min. One hundred fifty-one chronic dialysis patients participated in an 18-week study to evaluate clinical symptomatology when bicarbonate was substituted for acetate as the dialysis base buffer. Evaluation of each dialysis treatment (total of 8,183 treatments) consisted of both subjective and objective criteria (vomiting, angina, cramps, hypotension, and frequency of use of mannitol, hypertonic saline, and nitroglycerine). The patients were unaware of the change in dialysate solutions. There was a significant reduction (p less than 0.001) in the incidence of vomiting, cramps, hypotension, nausea, flushing, and the use of mannitol and hypertonic saline during bicarbonate dialysate treatment compared with acetate dialysate. Shortness of breath, angina, mental confusion, and paresthesias were not statistically changed. Although the method of HCO3 dialysate production is associated with occasional higher bacterial count than currently recommended by AAMI standards, no adverse reactions were observed in patients treated with standard efficiency dialyzers. It is concluded that the process for incenter HCO3 production is safe, economical, and better tolerated than acetate dialysate.

Unusual presentation of tuberculosis in chronic hemodialysis patients.

Four patients developed miliary tuberculosis while undergoing chronic hemodialysis. Two patients had diabetes mellitus. Three of the four patients were hemodialyzed 18--24 months prior to the onset of symptoms. Signs and symptoms included prolonged fever, pleural effusion, pericarditis with pericardial effusion, abdominal pain, weight loss, and ascites. All patients were PPD negative and without historical or radiographic evidence of latent tuberculosis. Disseminated tuberculosis was proven at autopsy in three patients. M. tuberculosis was eventually recovered from pleural fluid and urine in the fourth patient. The immune deficiencies of chronic renal failure and diabetes mellitus are suspected predisposing factors to the development of miliary tuberculosis in these patients.