Performance of Layer-by-Layer-Modified Multibore® Ultrafiltration Capillary Membranes for Salt Retention and Removal of Antibiotic Resistance Genes

Polyether sulfone Multibore^® ultrafiltration membranes were modified using polyelectrolyte multilayers via the layer-by-layer (LbL) technique in order to increase their rejection capabilities towards salts and antibiotic resistance genes. The modified capillary membranes were characterized to exhibit a molecular weight cut-off (at 90% rejection) of 384 Da. The zeta-potential at pH 7 was −40 mV. Laboratory tests using single-fiber modified membrane modules were performed to evaluate the removal of antibiotic resistance genes; the LbL-coated membranes were able to completely retain DNA fragments from 90 to 1500 nt in length. Furthermore, the pure water permeability and the retention of single inorganic salts, MgSO₄, CaCl₂ and NaCl, were measured using a mini-plant testing unit. The modified membranes had a retention of 80% toward MgSO₄ and CaCl₂ salts, and 23% in case of NaCl. The modified membranes were also found to be stable against mechanical backwashing (up to 80 LMH) and chemical regeneration (in acidic conditions and basic/oxidizing conditions).

Acetazolamide and Hydrochlorothiazide Followed by Furosemide Versus Furosemide and Hydrochlorothiazide Followed by Furosemide for the Treatment of Adults With Nephrotic Edema: A Randomized Trial

BACKGROUND

Nephrotic edema is considered refractory if it does not respond to maximum or near-maximum doses of loop diuretics. This condition can be treated with loop diuretics and thiazides. However, animal studies show that the simultaneous downregulation of pendrin with acetazolamide and inhibition of the sodium-chloride cotransporter with hydrochlorothiazide generates significant diuresis, and furosemide administration following a pendrin inhibitor potentiates furosemide's diuretic effect. Therefore, we performed this study to compare the efficacy of acetazolamide and hydrochlorothiazide followed by furosemide versus furosemide and hydrochlorothiazide followed by furosemide for treatment of refractory nephrotic edema.

STUDY DESIGN

Randomized, double-blind, 2-arm, parallel trial.

SETTING & PARTICIPANTS

20 patients with refractory nephrotic edema despite treatment with 80mg of furosemide daily and creatinine clearance > 60mL/min.

INTERVENTION

Patients were randomly assigned to 2 groups: group 1 (n=10) received 250mg of acetazolamide and 50mg of hydrochlorothiazide daily and group 2 (n=10) received 40mg of furosemide and 50mg of hydrochlorothiazide daily for 1 week in phase 1. In phase 2, both groups received 40mg of furosemide daily for 2 weeks.

OUTCOMES

The primary outcome was absolute change in weight before and at the end of each phase.

MEASUREMENTS

Weight and 24-hour urine volume at baseline and the end of each phase.

RESULTS

The mean weight decrease was of significantly larger magnitude in group 1 compared with group 2 at the end of phase 1 (-1.4±0.52 [SD] vs -0.65±0.41kg; P=0.001) and phase 2 (-1.6±0.84 vs -0.5±0.47kg; P=0.005). The increase in 24-hour urine volume was also significantly higher in group 1 at the end of phase 2.

LIMITATIONS

Small sample size, short follow-up duration, and lack of serum bicarbonate and chloride measurement.

CONCLUSIONS

Acetazolamide and hydrochlorothiazide followed by furosemide is more effective than furosemide and hydrochlorothiazide followed by furosemide for the treatment of refractory nephrotic edema.

Treating volume overload in acutely decompensated heart failure: established and novel therapeutic approaches

BACKGROUND

Most patients hospitalized for acutely decompensated heart failure (ADHF) present with symptoms and signs of volume overload, which is also associated with substantially high rates of death and rehospitalization in ADHF.

OBJECTIVE

To review the recent experimental and clinical evidence on existing therapeutic algorithms and investigational drugs used for the treatment of volume overload in ADHF patients.

METHODS

A systematic search of peer-reviewed publications was performed on Medline and EMBASE from January 1990 to March 2012. The results of unpublished trials were obtained from presentations at national and international meetings.

RESULTS

Apart from intrinsic renal insufficiency and neurohormonal activation, volume overload through venous congestion may be the primary haemodynamic factor triggering the worsening of renal function in ADHF patients. It is well known that heart and kidneys are closely interrelated and an acute or chronic disorder in one organ may induce acute or chronic dysfunction in the other organ. Established therapeutic strategies, (e.g. loop diuretics, vasodilators, and inotropes), are sometimes associated with limited clinical success due to tolerance and the need for frequent up titration of the doses in order to achieve the desired effect. That leads to an increasing interest in novel options, such as the use of adenosine A1 receptor antagonists, vasopressin antagonists, and renal-protective dopamine. Initial clinical trials have shown quite encouraging results in some heart failure subpopulations but have failed to demonstrate a clear beneficial role of these agents. On the other hand, ultrafiltration appears to be a more promising therapeutic procedure that will improve volume regulation, while preserving renal and cardiac function.

CONCLUSION

Further clinical studies are required in order to determine their net effect on renal function and potential cardiovascular outcomes. Until then, management of volume overload in ADHF patients remains a challenge for the clinicians.