Development of murine bariatric surgery models: lessons learned.

Roux-en-Y gastric bypass (RYGB) improves comorbidities such as diabetes and hypertension and lowers the risk of obesity-related cancers. To better understand the physiologic and genetic influences of bariatric surgery, a reliable murine model is needed that can be extended to genetically engineered mice. Given the complexity of these procedures, few researchers have successfully implemented these techniques beyond larger rodent models. The purpose of our study was to develop a technically feasible and reproducible murine model for RYGB and sleeve gastrectomy (SG). Mice were converted to liquid diet perioperatively without fasting and housed in groups on raised wire platforms. SG involved significant reduction of stomach volume followed by multilayer repair of the gastrotomy. RYGB procedure consisted of side-to-side, functional end-to-side bowel anastomoses and exclusion of the stomach medial to the gastroesophageal junction. Sham surgeries consisted of enterotomies and gastrotomy followed by primary repair without resection or rerouting. Survival after incorporation of the aforementioned techniques was 100% in the SG group and 41% in the RYGB group at 1 mo after surgery. Only 26% of RYGB mortality was attributed to leak, obstruction, or stricture; the majority of postoperative mortality was due to stress, dumping, or malnutrition. Much of the survival challenge for this surgical model was related to perioperative husbandry, which is to be expected given their small stature and poor response to stress. Utilization of the perioperative and surgical techniques described will increase survival and feasibility of these technically challenging procedures, allowing for a better understanding of mechanisms to explain the beneficial effects of bariatric surgery.

Colorectal cancer lung metastasis treatment with polymer-drug nanoparticles.

Colorectal cancer (CRC) is the second leading cause of cancer deaths in the United States; the predominant cause for mortality is metastasis to distant organs (e.g., lung). A major problem limiting the success of chemotherapy in metastatic CRC is the inability to target tumor tissues selectively and avoid severe side effects to normal tissues and organs. Here, we demonstrate polymeric nanoparticles (PNPs) entrapping chemotherapeutic agents provide a new therapeutic option for treating CRC that has metastasized to the lung. PNPs assembled from FDA approved biocompatible block copolymer accumulated predominantly in lung tissue. PNPs showed negligible accumulation in liver, spleen and kidneys, which was confirmed by fluorescent nanoparticle imaging and analysis of PI3K inhibition in the organs. PNPs entrapping PI3K inhibitors (i.e., wortmannin and PX866) suppressed CRC lung metastasis growth, and SN-38-loaded PNPs completely eliminated CRC lung metastasis. Our results demonstrate that polymer-drug nanoparticles offer a new approach to reduce toxicity of cancer therapy and has the potential to improve outcomes for patients with lung metastasis.

Failure to operate on resectable gastric cancer: implications for policy changes and regionalization.

BACKGROUND: A significant proportion of patients never receive curative-intent surgery for resectable gastric cancer (GC). The primary aims of this study were to identify disparities and targetable risk factors associated with failure to operate in the context of national trends in surgical rates for resectable GC. METHODS: The National Cancer Database was used to identify patients with resectable GC (adenocarcinoma, clinical stage IA-IIIC, 2004-2013). Multivariate modeling was used to identify predictors of resection and to analyze the impact of surgery on overall survival (OS). RESULTS: Of 46,970 patients with resectable GC, 18,085 (39%) did not receive an appropriate operation. Among unresected patients, 69% had no comorbidities. Failure to resect was associated with reduced median OS (44.4 versus 11.8 mo, hazard ratio [HR]: 2.09, P < 0.001). In the multivariate analysis, the most critical factors affecting OS were resection (HR: 2.09) and stage (reference IA; HR range: 1.16-3.50, stage IB-IIIC). Variables independently associated with no surgery included insurance other than private or Medicare (odds ratio [OR]: 1.60/1.54), nonacademic/nonresearch hospital (OR: 1.16), non-Asian race (OR: 1.72), male (OR: 1.19), older age (OR: 1.04), Charlson-Deyo score >1 (OR: 1.17), residing in areas with median income <$48,000 (OR: 1.23), small urban populations <20,000 (OR: 1.41), and stage (reference IA; OR range: 1.36-3.79, stage IB-IIIC, P < 0.001). CONCLUSIONS: Over one-third of patients with resectable GC fail to receive surgery. Suitable insurance coverage and treatment facility are the most salient (and only modifiable) risk factors for omitting surgery. To mitigate national disparities in surgical care, policymakers should consider improving insurance coverage in underserved areas and regionalization of gastric cancer care.

The Nonwhite Woman Surgeon: A Rare Species.

BACKGROUND: As of 2012, 39% of medical student graduates were nonwhite, yet very few nonwhite women graduates chose to become surgeons. METHODS: To better understand issues regarding nonwhite women in surgery, an online survey was sent to surgeons across the United States. Results are based on self-reported data. Mean data are reported. RESULTS: A total of 194 surgeons (42% women) completed the survey; only 12% of responders were nonwhite. Overall, 56% of nonwhite women felt they earned less than what men surgeons earn for equal work. Nonwhite women surgeons earned less than what men surgeons ($224,000 vs. 351,000, p < 0.00002) and white women surgeons ($285,000, p = 0.02) earned. Overall, 96% of nonwhite surgeons believed that racial discrimination currently exists among surgeons. CONCLUSIONS: The few nonwhite women surgeons in the United States recognize that they are paid significantly less than what other surgeons are paid. Inequitable remuneration and a discriminatory work environment encountered by nonwhite women surgeons must be addressed.

Fast left prefrontal rTMS reduces post-gastric bypass surgery pain: findings from a large-scale, double-blind, sham-controlled clinical trial.

BACKGROUND: A single session of left prefrontal rTMS has been shown to have analgesic effects, and to reduce post-operative morphine use. We sought to test these findings in a larger sample, and try and see if multiple sessions had additive analgesic benefit. METHODS: 108 patients undergoing laparoscopic gastric bypass surgery received two sessions of 10 Hz rTMS (110% of motor threshold) over the left dorsolateral prefrontal cortex (one immediately following surgery and one 4 h later). Participants were randomly assigned to receive 2 sessions of real rTMS, 2 sessions of sham, 1 real then 1 sham, or 1 sham then 1 real rTMS treatments. Patients and study staff were blind to rTMS conditions. RESULTS: Unlike previous rTMS trials for post-operative pain, no differences emerged between groups with respect to total patient-controlled analgesia usage (IV hydromorphone). However, despite no difference in IV analgesic usage, subjects that received 2 real rTMS sessions rated both the affective and sensory dimensions of their pain significantly lower than those in the sham­sham group at several time points during the post-surgical/post-rTMS period. CONCLUSIONS: This study suggests that left prefrontal rTMS may produce significant analgesic effects in the perioperative setting. However, further work is needed to understand this effect and attempt to make it clinically useful in light of the lack of effect on PCA hydromorphone use.

Ten sessions of adjunctive left prefrontal rTMS significantly reduces fibromyalgia pain: a randomized, controlled pilot study.

Transcranial magnetic stimulation (TMS) of the prefrontal cortex can cause changes in acute pain perception. Several weeks of daily left prefrontal TMS has been shown to treat depression. We recruited 20 patients with fibromyalgia, defined by American College of Rheumatology criteria, and randomized them to receive 4000 pulses at 10 Hz TMS (n=10), or sham TMS (n=10) treatment for 10 sessions over 2 weeks along with their standard medications, which were fixed and stable for at least 4 weeks before starting sessions. Subjects recorded daily pain, mood, and activity. Blinded raters assessed pain, mood, functional status, and tender points weekly with the Brief Pain Inventory, Hamilton Depression Rating Scale, and Fibromyalgia Impact Questionnaire. No statistically significant differences between groups were observed. Patients who received active TMS had a mean 29% (statistically significant) reduction in pain symptoms in comparison to their baseline pain. Sham TMS participants had a 4% nonsignificant change in daily pain from their baseline pain. At 2 weeks after treatment, there was a significant improvement in depression symptoms in the active group compared to baseline. Pain reduction preceded antidepressant effects. TMS was well tolerated, with few side effects. Further studies that address study limitations are needed to determine whether daily prefrontal TMS may be an effective, durable, and clinically useful treatment for fibromyalgia symptoms.