Risk of ventricular dysrhythmias during 1-hour infusions of amphotericin B in patients with preserved renal function

The Inducible lac Operator-Repressor System Is Functional in Zebrafish Cells

Background

Zebrafish are a foundational model organism for studying the spatio-temporal activity of genes and their regulatory sequences. A variety of approaches are currently available for editing genes and modifying gene expression in zebrafish, including RNAi, Cre/lox, and CRISPR-Cas9. However, the lac operator-repressor system, an E. coli lac operon component which has been adapted for use in many other species and is a valuable, flexible tool for inducible modulation of gene expression studies, has not been previously tested in zebrafish.

Results

Here we demonstrate that the lac operator-repressor system robustly decreases expression of firefly luciferase in cultured zebrafish fibroblast cells. Our work establishes the lac operator-repressor system as a promising tool for the manipulation of gene expression in whole zebrafish.

Conclusion

Our results lay the groundwork for the development of lac-based reporter assays in zebrafish, and adds to the tools available for investigating dynamic gene expression in embryogenesis. We believe this work will catalyze the development of new reporter assay systems to investigate uncharacterized regulatory elements and their cell-type specific activities.

Antifungal agents. Part I. Amphotericin B preparations and flucytosine

Traditionally, amphotericin B has been the cornerstone of antifungal treatment. Toxicity, however, is a major dose-limiting factor of amphotericin B deoxycholate. Nevertheless, it continues to have a major role in the treatment of deep-seated mycotic infections. Recently, less nephrotic lipid formulations, including amphotericin B lipid complex, amphotericin B cholesteryl sulfate, and liposomal amphotericin B, have been introduced. The pharmacologic properties, main indications, recommended dosages, related costs, and adverse effects of these various preparations are summarized in this review. Orally administered flucytosine is useful in certain infections, particularly cryptococcal meningitis, but it should be used with caution in patients with renal insufficiency.

Amphotericin B-associated hypertension

OBJECTIVE

To report two cases of hypertension related to amphotericin B infusion.

CASE SUMMARY

A 63-year-old woman with Candida albicans bacteremia and an 84-year-old man with Aspergillus fumigatus pneumonia developed hypertension within minutes of amphotericin B administration. Both patients' blood pressure returned to baseline soon after the infusion of amphotericin B was stopped. Neither patient was rechallenged.

DISCUSSION

A causal relationship may exist between the administration of amphotericin B and these hypertensive episodes. Blood pressure in both patients normalized without treatment on discontinuation of the infusion. The mechanism of amphotericin B-associated hypertension is unclear but could include vasoconstricting properties of the drug or the administration of intravenous NaCl 0.9% prior to amphotericin B infusion. We recommend that intravenous NaCl 0.9% be administered following amphotericin B infusion and that the infusion be stopped if hypertensive episodes arise.

CONCLUSIONS

Both acute hypertension and hypotension can occur in patients receiving amphotericin B for systemic fungal infections.

Amphotericin B infusion-related toxicity: comparison of two- and four-hour infusions

OBJECTIVE

To investigate the influence of infusion duration on infusion-related adverse effects (IRAEs) associated with prophylactic or treatment regimens of amphotericin B in patients with leukemia/bone marrow transplant (BMT).

DESIGN

Randomized, double-blind, 2-arm, complete crossover, prospective clinical trial.

SETTING

A university-affiliated tertiary care teaching hospital.

PARTICIPANTS

The study population consisted of 25 consecutive patients with leukemia/BMT who received 162 prophylactic regimen infusions and 169 treatment regimen infusions of amphotericin B via a central line. Prior to each infusion all patients received a parenteral IRAE prophylaxis regimen of diphenhydramine 25 mg and hydrocortisone 25 mg. No test doses or incremental amphotericin B doses were administered. Patients were monitored closely for IRAEs, which were documented by using a standardized data collection form.

MAIN OUTCOME MEASURES

The incidence and nature of IRAEs during a 6-hour monitoring period following the initiation of each infusion was measured. Patients served as their own controls. IRAEs were compared according to infusion duration and therapeutic indication.

RESULTS

Three hundred and thirty-one 2- and 4-hour amphotericin B infusions were administered. We found no difference between 2- and 4-hour infusions in the incidence and severity of IRAEs, including overall events (29% of 166 2-hour infusions vs. 25% of 165 4-hour infusions), chill scores (8% of 166 2-hour infusions vs. 7% of 165 4-hour infusions; highest score 7 vs. 6), nausea and vomiting (7% vs. 12%; highest score 4 in both groups), fever (3% vs. 2%), highest temperature increase (2.4 vs. 1.6 degrees C), systolic hypotension (6% vs. 2%), greatest decrease from baseline (40 vs. 62 mm Hg), diastolic hypotension (5% vs. 3%), and greatest decrease (30 vs. 28 mm Hg) (p > 0.05). Overall, IRAEs were less common in prophylactic treatment regimens (35 events [22%] in 162 infusions) than in treatment regimens (55 events [32%] in 169 infusions) (p < 0.05).

CONCLUSIONS

This study demonstrates that patients with leukemia/BMT without myocardial or renal dysfunction who receive hydrocortisone and diphenhydramine as premedications can tolerate 2-hour central line infusions of prophylactic or treatment regimens of amphotericin B as well as 4-hour infusions.

Rapid infusion of amphotericin B in dextrose

OBJECTIVE

To review the data examining the use of rapid infusion of amphotericin B in dextrose infusions.

DATA SOURCES

A MEDLINE search of the English-language literature and review of pertinent references' bibliographies was used to identify articles evaluating the effect of amphotericin B infusion rates on the incidence of adverse reactions.

STUDY SELECTION AND DATA EXTRACTION

Controlled and uncontrolled studies involving humans are reviewed; emphasis is placed on recent comparative trials. Pertinent information, as judged by the authors, was selected for discussion.

DATA SYNTHESIS

Amphotericin B, a polyene antifungal agent with significant toxicity, remains the agent of choice for many serious fungal infections. The potential benefits of rapid administration of amphotericin B in reducing the incidence and/or severity of adverse reactions were noted soon after its introduction. Recent studies have examined the tolerability of rapid (0.75-1 h) amphotericin B infusions. Results of studies assessing the tolerability of rapid amphotericin B infusions suggest that tolerance to infusion-related reactions develops during therapy. Comparative trials have obtained variable results. The comparative trials supporting rapid amphotericin B infusion have generally used crossover designs, enrolled small numbers of patients, and excluded patients with significant renal or cardiovascular dysfunction.

CONCLUSIONS

Rapid amphotericin B infusions should be avoided during initiation of therapy when infusion-related reactions tend to be most problematic, and in patients with cardiovascular disease, renal dysfunction, and potassium disorders because of the potential risk for cardiac arrhythmias. The literature currently available is conflicting and insufficient to support the routine use of rapid amphotericin B infusion.