Time-lapse confocal microscopy to study in vitro Streptococcus mutans surface colonization.

The cariogenicity of Streptococcus mutans relates to its ability to form biofilms on dental surfaces. The aim of this work was to develop a flowcell system compatible with time-lapse confocal microscopy to compare the adhesion and accumulation of S. mutans cells on surfaces in unsupplemented media against media containing sucrose or sucralose (a non-metabolized sweetener) over a short period of time. Fluorescent S. mutans 3209/pVMCherry was suspended in unsupplemented media or media supplemented with 1% sucrose or 1% sucralose and passed through a 3D-printed flowcell system. Flowcells were imaged over 60 minutes using a confocal microscope. Image analysis was performed, including a newly developed object-movement-based method to measure biomass adhesion. Streptococcus mutans 3209/pVMCherry grown in 1% sucrose-supplemented media formed small, dense, relatively immobile clumps in the flowcell system measured by biovolume, surface area, and median object centroid movement. Sucralose-supplemented and un-supplemented media yielded large, loose, mobile aggregates. Architectural metrics and per-object movement were significantly different (P < 0.05) when comparing sucrose-supplemented media to either unsupplemented or sucralose-supplemented media. These results demonstrate the utility of a flowcell system compatible with time-lapse confocal microscopy and image analysis when studying initial biofilm formation and adhesion under different nutritional conditions.

Localized muscle spasm as a manifestation of pembrolizumab-induced infusion reaction.

INTRODUCTION: As immune checkpoint inhibitors increasingly gain oncological utility, the incidence of unique adverse events may rise as well. The description and management of localized, recurrent muscle spasms secondary to pembrolizumab infusions has not previously been reported. CASE REPORT: A 64-year-old male receiving pembrolizumab infusions experienced acute-onset, isolated spasms and pain occurring in cycles 2 through 5.Management and outcome: Pretreatment with intravenous lorazepam, diphenhydramine, famotidine, ondansetron, and fluids have led to spasm-free pembrolizumab infusions. DISCUSSION: The purpose of this report is to provide the first known incidence and successful corrective measures taken for localized muscle spasms secondary to pembrolizumab infusion.

A multicenter study evaluating the effectiveness and safety of single-dose low molecular weight iron dextran vs single-dose ferumoxytol for the treatment of iron deficiency.

There are multiple intravenous (IV) iron formulations available, of which several may be administered as single-dose infusions such as low-molecular weight iron dextran (LMWID), ferumoxytol, ferric carboxymaltose, and ferric derisomaltose. However, administration of ferumoxytol as a single-dose infusion is off-label as it is approved as a two-dose series. Previous studies of ferumoxytol alone support the effectiveness and safety of the single-dose regimen, but there is a paucity of data directly comparing single-dose ferumoxytol to other single-dose IV iron formulations. This multicenter cohort study sought to affirm the safety and effectiveness of single-dose ferumoxytol compared to single-dose LMWID. Overall, 906 patients who received single-dose LMWID (n = 439) or ferumoxytol (n = 467) were identified, of whom 351 met criteria for the primary effectiveness endpoint defined as median change in hemoglobin (Hb), hematocrit (Hct), and ferritin 8 to 12 weeks from baseline. All 906 patients were included for the secondary analysis evaluating the incidence of adverse events (AE) and requirement of additional IV iron infusions. Median change in Hb (LMWID 0.5 g/dL; ferumoxytol 0.8 g/dL; P = .24), Hct (LMWID 1.1%; ferumoxytol 1.25%; P = .89), and ferritin (LMWID 87 ng/dL; ferumoxytol 71 ng/dL; P = .47) was not significantly different between groups. Both groups experienced similar rates of AEs (LMWID 2.3%; ferumoxytol 2.8%; P = .63). The LMWID patients more frequently required additional IV iron infusions (LMWID 28.5%; ferumoxtyol 16.1%; P < .001). These findings support that single-dose ferumoxytol is effective and safe, and that patients may require fewer additional infusions compared to patients who received LMWID.

Dosing Oncology Therapeutics in Combination Therapy for Renal Dysfunction: The University of California San Diego Study of Personalized Cancer Therapy to Determine Response and Toxicity (UCSD-PREDICT) Experience.

Introduction Dose reductions are often required to avoid toxicity in combination therapy for advanced cancers, but information on appropriate dose reductions in renal dysfunction is lacking. This study assessed dose reductions of renally cleared oncology agents given in combination therapy in the setting of renal dysfunction. Methods A database of 1,072 patients was screened to identify patients with renal dysfunction (glomerular filtration rate < 60 mL/min) receiving oncology combination therapy with at least one agent requiring dose reduction for renal insufficiency. The dose of the renal agent was compared to the single-agent renal dosing recommendations to calculate a dose percentage. Tolerability was determined from electronic medical records review. Results Thirty-three regimens (n = 25 patients) were identified: 11 included at least one targeted agent (n = 8 patients) and 22 had only cytotoxic chemotherapy (n = 18 patients). The renal agent was given at the recommended single-agent renal dose in ~50% of combinations; ~50% of all regimens were tolerated, and only six combinations had dose reductions for toxicity. The median final dose percentage was 100% of the recommended renal dose (range: 25% - 333%); no significant differences were seen between groups (cytotoxic - tolerated, cytotoxic - not tolerated, targeted - tolerated, targeted - not tolerated; p = 0.38). No significant differences were observed between tolerated vs. non-tolerated (p = 0.97) or targeted vs. cytotoxic (p = 0.80) regimens. Conclusions Dose reductions of renally cleared agents are highly variable in oncology patients with renal dysfunction. Additional studies are needed to determine appropriate dosing adjustments in this population.