Comparison of techniques for culture of dialysis water and fluid.

INTRODUCTION: Microbiological culture of dialysis water and fluid is a routine safety measure. In the United States (U.S.), laboratories perform these cultures on trypticase soy agar at 35-37°C for 48 h (TSA-48h), not on the tryptone glucose extract agar or Reasoner's 2A agar at 17-23°C for 7 days (TGEA-7d and R2A-7d, respectively) recommended by international standards. We compared culture methods to identify samples exceeding the accepted action level of 50 CFU/mL. METHODS: Dialysis water and fluid samples collected from 41 U.S. dialysis programs between 2011 and 2014 were cultured at two U.S. laboratories. Each sample was cultured using (1) either TGEA-7d or R2A-7d and (2) TSA-48h. We compared proportions exceeding the action level by different methods and test characteristics of TSA-48h to those of TGEA-7d and R2A-7d. FINDINGS: The proportion of water samples yielding colony counts ≥50 CFU/mL by TGEA-7d was significantly different from the proportion by TSA-48h (P = 0.001; difference in proportion 4.3% [95%CI 1.3-7.3%]). The proportions of dialysis fluid samples ≥50 CFU/mL by TGEA-7d and TSA-48h were not significantly different; there were no significant differences for comparisons of R2A-7d to TSA-48h. DISCUSSION: In dialysis fluid, TSA-48h was comparable to TGEA-7d and R2A-7d in identifying samples as having bacterial counts ≥50 CFU/mL. In dialysis water, TSA-48h was comparable to R2A-7d in identifying samples ≥50 CFU/mL, but TGEA-7d did yield significantly more results above 50 CFU/mL. Nonetheless, the negative predictive value of a TSA-48h result of <50 CFU/mL in dialysis water exceeded 95%.

A first-in-man, randomized, placebo-controlled study to evaluate the safety and feasibility of autologous delipidated high-density lipoprotein plasma infusions in patients with acute coronary syndrome.

OBJECTIVES: This study aimed to determine whether serial autologous infusions of selective high-density lipoprotein (HDL) delipidated plasma are feasible and well tolerated in patients with acute coronary syndrome (ACS). BACKGROUND: Low HDL is associated with increased risk of cardiovascular disease. Plasma selective delipidation converts alphaHDL to prebeta-like HDL, the most effective form of HDL for lipid removal from arterial plaques. METHODS: ACS patients undergoing cardiac catheterization with >or=1 nonobstructive native coronary artery atheroma were randomized to either 7 weekly HDL selective delipidated or control plasma apheresis/reinfusions. Patients underwent intravascular ultrasound (IVUS) evaluation of the target vessel during the catheterization for ACS and up to 14 days following the final apheresis/reinfusion session. 2-D gel electrophoresis of delipidated plasmas established successful conversion of alphaHDL to prebeta-like HDL. The trial was complete with 28 patients randomized. RESULTS: All reinfusion sessions were tolerated well by all patients. The levels of prebeta-like HDL and alphaHDL in the delipidated plasma converted from 5.6% to 79.1% and 92.8% to 20.9%, respectively. The IVUS data demonstrated a numeric trend toward regression in the total atheroma volume of -12.18 +/- 36.75 mm(3) in the delipidated group versus an increase of total atheroma volume of 2.80 +/- 21.25 mm(3) in the control group (p = 0.268). CONCLUSIONS: In ACS patients, serial autologous infusions of selective HDL delipidated plasma are clinically feasible and well tolerated. This therapy may offer a novel adjunct treatment for patients presenting with ACS. Further study will be needed to determine its ability to reduce clinical cardiovascular events.

Selective delipidation of plasma HDL enhances reverse cholesterol transport in vivo.

Uptake of cholesterol from peripheral cells by nascent small HDL circulating in plasma is necessary to prevent atherosclerosis. This process, termed reverse cholesterol transport, produces larger cholesterol-rich HDL that transfers its cholesterol to the liver facilitating excretion. Most HDL in plasma is cholesterol-rich. We demonstrate that treating plasma with a novel selective delipidation procedure converts large to small HDL [HDL-selectively delipidated (HDL-sdl)]. HDL-sdl contains several cholesterol-depleted species resembling small alpha, prebeta-1, and other prebeta forms. Selective delipidation markedly increases efficacy of plasma to stimulate ABCA1-mediated cholesterol transfer from monocytic cells to HDL. Plasma from African Green monkeys underwent selective HDL delipidation. The delipidated plasma was reinfused into five monkeys. Prebeta-1-like HDL had a plasma residence time of 8 +/- 6 h and was converted entirely to large alpha-HDL having residence times of 13-14 h. Small alpha-HDL was converted entirely to large alpha-HDL. These findings suggest that selective HDL delipidation activates reverse cholesterol transport, in vivo and in vitro. Treatment with delipidated plasma tended to reduce diet-induced aortic atherosclerosis in monkeys measured by intravascular ultrasound. These findings link the conversion of small to large HDL, in vivo, to improvement in atherosclerosis.