Flash nanoprecipitation assisted self-assembly of ionizable lipid nanoparticles for nucleic acid delivery.

Ionizable lipid nanoparticles (LNPs) have emerged as a powerful tool for the intracellular delivery of nucleic acids. Following the recent success of LNP-based siRNA therapeutics and mRNA vaccines, the use of ionizable lipids for nucleic acid delivery has tremendously increased. Here, we introduce a flash nanoprecipitation (FNP) approach using the confined impingement (CIJ) mixer to stably self-assemble ionizable LNPs. To validate this approach, we employed three clinically relevant LNP formulations containing SM102, ALC0315, and DLin-MC3-DMA as ionizable lipids. FNP-assembled LNPs showed >95% encapsulation efficiency of mRNA and siRNA payloads and particle sizes below 150 nm. SM102 or ALC0315 LNPs demonstrated efficient delivery of mRNA into immune cells in vitro and to lymphoid organs in vivo, whereas Dlin-MC3-DMA LNPs allowed effective intracellular siRNA delivery with great functional ability. The FNP technique could economically produce LNPs in smaller volumes that are highly suitable for the discovery phase.

Irradiator Commissioning and Dosimetry for Assessment of LQ α and ß Parameters, Radiation Dosing Schema, and in vivo Dose Deposition.

Radiation dosimetry is critical in the accurate delivery and reproducibility of radiation schemes in preclinical models for high translational relevance. Prior to performing any in vitro or in vivo experiments, the specific dose output for the irradiator and individual experimental designs must be assessed. Using an ionization chamber, electrometer, and solid water setup, the dose output of wide fields at isocenter can be determined. Using a similar setup with radiochromic films in the place of the ionization chamber, dose rates for smaller fields at different depths can also be determined. In vitro clonogenic survival assays of cancer cells in response to radiation treatment are inexpensive experiments that provide a measure of inherent radio-sensitivity of cell lines by fitting these data with the traditional linear-quadratic model. Model parameters estimated from these assays, combined with the principles of biologic effective doses, allows one to develop varying fractionation schedules for radiation treatment that provide equivalent effective doses in tumor-bearing animal experiments. This is an important factor to consider and correct for in comparing in vivo radiation therapy schedules to eliminate potential confounding of results due to variance in the delivered effective doses. Taken together, this article provides a general method for dose output verification preclinical animal and cabinet irradiators, in vitro assessment of radio-sensitivity, and verification of radiation delivery in small living organisms.

Bicuspidization of the tricuspid valve for the treatment of posterior leaflet endocarditis: a case report.

Patients who require surgical therapy for the treatment of tricuspid valve regurgitation can avoid undergoing tricuspid valve replacement if valve-sparing repair techniques are employed. Tricuspid valvular endocarditis frequently requires valvectomy, leaving the right side of the heart and pulmonary system vulnerable to unregulated blood flow. We present a case of complete posterior leaflet excision and plication of the involved portion of the tricuspid annulus, which resulted in "bicuspidization" of the valve, for the treatment of tricuspid valve endocarditis localized to the posterior leaflet.