Using our recently developed rat model of RYGB, we found that postoperative weight loss is correlated with the magnitude of the decrease in circulating ghrelin levels. This correlation provides the strongest evidence to date that altered ghrelin signaling contributes to weight loss after this operation. The lower level of circulating ghrelin after RYGB likely blunts the appetitive drive, leading to decreased food intake in these animals.

The hydrogel sealant can be observed with cross sectional imaging and can be distinguished from cerebrospinal fluid using a CT scan, complemented by an occasional MRI scan. In addition, complete absorption of the hydrogel, with closure of the remaining void was noted. Histological examination found an unremarkable response with no neurotoxicity or space-filling defect.

Despite significant technical advances in radiation delivery, conventional whole brain radiation therapy (WBRT) has not materially changed in the past 50 years. We hypothesized that IMRT can selectively spare uninvolved brain and scalp with the goal of reducing acute and late toxicity. MRI/CT simulation image registration was performed. We performed IMRT planning to simultaneously treat the brain tumor(s) on MRI + 5 mm margin to 37.5 Gy in 15 fractions while limiting the uninvolved brain + 2 mm margin to 30 Gy in 15 fractions and the mean scalp dose to #18 Gy. Three field IMRT plans were compared to conventional WBRT plans. Symptomatic patients were started on conventional WBRT for 2 to 3 fractions while IMRT planning was performed. Seventeen consecutive patients with brain metastases with RPA class I and II disease with no leptomeningeal spread were treated with IMRT WBRT. Compared to conventional WBRT, IMRT reduced the mean scalp dose (26.2 Gy vs. 16.4 Gy, p < 0.001) and the mean PTV30 dose (38.4 Gy vs. 32.0 Gy, p < 0.001) while achieving similar mean PTV37.5 doses (38.3 Gy vs. 38.0 Gy, p = 0.26). Using Olsen hair loss score criteria, 4 of 15 assessable patients preserved at least 50% of hair coverage at 1 to 3 months after treatment while 6 patients preserved between 25 and 50% hair coverage. At a median follow-up of 6.8 months (range: 5 to 15 months), the median overall survival was 5.4 months. Four patients relapsed within the brain, one within the PTV37.5 and three outside the PTV37.5. Tumor directed, scalp sparing IMRT is feasible, achieves rational dose distributions and preserves partial hair coverage in the majority of patients. Further studies are warranted to determine whether the increased utilization of resources needed for IMRT are appropriate in this setting.

Abstract.Radiation technique for prostate cancer has continuously evolved over the past several decades. The aim of the present study was to describe the effects of implementing modern prostate intensity-modulated radiation therapy (M-IMRT) on dosimetry and outcome. Between January 2010 and April 2012, 48 consecutive patients were treated with conventional prostate IMRT (C-IMRT) to a dose of 81 Gy. Between May 2012 and April 2015, 50 consecutive patients were treated with M-IMRT to the entire prostate to a dose of 75.6-79.2 Gy, while using prostate magnetic resonance imaging fusion, dose-volume constraints prioritizing normal tissue avoidance above planning target volume coverage, and boosting any dominant intraprostatic masses to 79.2-81 Gy. Rectal Dmax, V75, V60, V65 and V50, bladder Dmax, V75, V70 and V65, and acute and late toxicities were compared between the C-IMRT and M-IMRT groups. The median follow-up for the C-IMRT and M-IMRT groups was 61 vs. 26 months, respectively (P<0.001). M-IMRT resulted in a significant reduction in median rectal Dmax, rectal V75, rectal V70, rectal V65, bladder Dmax, bladder V75, bladder V70 and bladder V65 (P<0.01 for all). There was no significant difference in rectal V50. The 2-year rate of late grade ≥2 rectal bleeding was 13% with C-IMRT vs. 3% with M-IMRT (P=0.03). The 2-year rate of late grade ≥2 genitourinary toxicity was 11% for C-IMRT vs. 5% for M-IMRT (P= 0.21). There were no significant differences in acute toxicity, biochemical control or overall survival.Therefore, compared with C-IMRT, M-IMRT was associated with reduced rectal toxicity without compromising disease control.