High-Dose Ionizing Radiation Impairs Healthy Dendrite Growth in C. elegans.

Purpose: The nervous system is vulnerable to radiation damage, and further optimization is required to increase the efficacy of radiation therapy while reducing harm to neurons. Given recent developments in heavy ion therapy, experimental models would be valuable to improve these therapies. We used the nematode Caenorhabditis elegans (C. elegans) to evaluate the effects of high-dose radiation on neuron development. Methods and Materials: In this study, we used confocal microscopy to assess dendritic growth of the PVD nociceptor after high-dose gamma-irradiation from a Cs-137 source. Results: Irradiation during an early larval stage (L2) delayed overall development but also independently impaired dendrite outgrowth in the PVD nociceptive neuron. Irradiation at L4 larval stage did not result in significant alterations in dendrite morphology. Conclusions: The nematode C. elegans can serve as a high-throughput model to study the effects of high-dose radiation on dendrite growth. We propose that C. elegans can be useful for studies of experimental radiation therapy modalities and dose rates for translational research.

A pulmonary embolism response team's initial 20 month experience treating 87 patients with submassive and massive pulmonary embolism.

Pulmonary Embolism Response Teams (PERTs) have emerged to provide rapid multidisciplinary assessment and treatment of PE patients. However, descriptive institutional experience and preliminary outcomes data from such teams are sparse. PERT activations were identified through a retrospective review. Only confirmed submassive or massive PEs were included in the data analysis. In addition to baseline variables, the therapeutic intervention, length of stay (LOS), in-hospital mortality, and bleeding rate/severity were recorded. A total of 124 PERT activations occurred over 20 months: 43 in the first 10 months and 81 in the next 10. A total of 87 submassive (90.8%) and massive (9.2%) PE patients were included. The median age was 65 (51-75 IQR) years. Catheter-directed thrombolysis (CDT) was administered to 25 patients, systemic thrombolysis (ST) to six, and anticoagulation alone (AC) to 54. The median ICU stay and overall LOS were 6 (3-10 IQR) and 7 (4-14 IQR) days, respectively, with no association with any variables except a brain natriuretic peptide (BNP) >100 pg/mL ( p=0.008 ICU LOS; p=0.047 overall LOS). Twelve patients (13.7%) died in the hospital, nine of whom had metastatic or brain cancer, with a median overall LOS of 13 (11-17 IQR) days. There were five major bleeds: one in the CDT group, one in the ST group, and three in the AC group. Overall, (1) PERT activations increased after the first 10 months; (2) BNP >100 pg/mL was associated with a longer LOS; (3) rates of mortality and bleeding did not correlate with treatment; and (4) the majority of in-hospital deaths occurred in patients with advanced cancer.