Methylene blue dose-dependently induces cutaneous inflammation and heat hyperalgesia in a novel rat model.

Methylene blue (MB) has been shown to reduce mortality and morbidity in vasoplegic patients after cardiac surgery. Though MB is considered to be safe, extravasation of MB leading to cutaneous toxicity has been reported. In this study, we sought to characterize MB-induced cutaneous toxicity and investigate the underlying mechanisms. To induce MB-induced cutaneous toxicity, we injected 64 adult male Sprague-Dawley rates with 200 µL saline (vehicle) or 1%, 0.1%, or 0.01% MB in the plantar hind paws. Paw swelling, skin histologic changes, and heat and mechanical hyperalgesia were measured. Injection of 1%, but not 0.1% or 0.01% MB, produced significant paw swelling compared to saline. Injection of 1% MB produced heat hyperalgesia but not mechanical hyperalgesia. Pain behaviors were unchanged following injections of 0.1% or 0.01% MB. Global transcriptomic analysis by RNAseq identified 117 differentially expressed genes (111 upregulated, 6 downregulated). Ingenuity Pathway Analysis showed an increased quantity of leukocytes, increased lipids, and decreased apoptosis of myeloid cells and phagocytes with activation of IL-1ß and Fos as the two major regulatory hubs. qPCR showed a 16-fold increase in IL-6 mRNA. Thus, using a novel rat model of MB-induced cutaneous toxicity, we show that infiltration of 1% MB into cutaneous tissue causes a dose-dependent pro-inflammatory response, highlighting potential roles of IL-6, IL-1ß, and Fos. Thus, anesthesiologists should administer dilute MB intravenously through peripheral venous catheters. Higher concentrations of MB (1%) should be administered through a central venous catheter to minimize the risk of cutaneous toxicity.

Career Trajectory After General Surgery Residency: Do Academic Program Graduates Pursue Academic Surgery?

OBJECTIVE: Determine the proportion of contemporary US academic general surgery residency program graduates who pursue academic careers and identify factors associated with pursuing academic careers. SUMMARY BACKGROUND DATA: Many academic residency programs aim to cultivate academic surgeons, yet the proportion of contemporary graduates who choose academic careers is unclear. The potential determinants that affect graduates' decisions to pursue academic careers remain underexplored. METHODS: We collected program and individual-level data on 2015 and 2018 graduates across 96 US academic general surgery residency programs using public resources. We defined those pursuing academic careers as faculty within US allopathic medical school-affiliated surgery departments who published two or more peer-reviewed publications as the first or senior author between 2020-2021. After variable selection using sample splitting LASSO regression, multivariable regression evaluated association with pursuing academic careers among all graduates, and graduates of top-20 residency programs. Secondary analysis using multivariable ordinal regression explored factors associated with high research productivity during early faculty years. RESULTS: Among 992 graduates, 166 (17%) were pursuing academic careers according to our definition. Graduating from a top-20 ranked residency program (OR[95%CI]: 2.34[1.40-3.88]), working with a longitudinal research mentor during residency (OR[95%CI]: 2.21[1.24-3.95]), holding an advanced degree (OR[95%CI]: 2.20[1.19-3.99]), and the number of peer-reviewed publications during residency as first or senior author (OR[95%CI]: 1.13[1.07-1.20]) were associated with pursuing an academic surgery career, while the number of peer-reviewed publications before residency was not (OR[95%CI]: 1.08[0.99-1.20]). Among top 20 program graduates, working with a longitudinal research mentor during residency (OR[95%CI]: 0.95[0.43-2.09]) was not associated with pursuing an academic surgery career. The number of peer-reviewed publications during residency as first or senior author was the only variable associated with higher productivity during early faculty years (OR[95%CI]: 1.12[1.07-1.18]). CONCLUSIONS: Our findings suggest programs that aim to graduate academic surgeons may benefit from ensuring trainees receive infrastructural support and demonstrate sustained commitment to research throughout residency. Our results should be interpreted cautiously as the impact of unmeasured confounders is unclear.

Cyclin-dependent Kinase 1 and Aurora Kinase choreograph mitotic storage and redistribution of a growth factor receptor.

Endosomal trafficking of receptors and associated proteins plays a critical role in signal processing. Until recently, it was thought that trafficking was shut down during cell division. Thus, remarkably, the regulation of trafficking during division remains poorly characterized. Here we delineate the role of mitotic kinases in receptor trafficking during asymmetric division. Targeted perturbations reveal that Cyclin-dependent Kinase 1 (CDK1) and Aurora Kinase promote storage of Fibroblast Growth Factor Receptors (FGFRs) by suppressing endosomal degradation and recycling pathways. As cells progress through metaphase, loss of CDK1 activity permits differential degradation and targeted recycling of stored receptors, leading to asymmetric induction. Mitotic receptor storage, as delineated in this study, may facilitate rapid reestablishment of signaling competence in nascent daughter cells. However, mutations that limit or enhance the release of stored signaling components could alter daughter cell fate or behavior thereby promoting oncogenesis.

Fructose malabsorption and fructan malabsorption are associated in patients with irritable bowel syndrome.

BACKGROUND: Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and fructan. Prior studies examined fructose and fructan malabsorption separately in IBS patients. None have concurrently assessed both within the same patient group. We aimed to investigate the association between fructose and fructan malabsorption in the same patients with IBS using hydrogen breath testing (HBT). METHODS: We retrospectively identified patients with IBS who underwent fructose and fructan HBTs and abstracted their results from the electronic medical record. Fructose and fructan HBTs were performed by administering a 25 g fructose solution or 10 g fructan solution, followed by breath hydrogen readings every 30 min for 3 h. Patients were positive for fructose or fructan malabsorption if breath hydrogen levels exceeded 20 ppm. RESULTS: Of 186 IBS patients, 71 (38.2%) were positive for fructose malabsorption and 91 (48.9%) were positive for fructan malabsorption. Of these patients, 42 (22.6%) were positive for fructose malabsorption and fructan malabsorption. Positive fructose HBT readings were significantly associated with positive fructan HBT readings (p = 0.0283). Patients positive for fructose malabsorption or fructan malabsorption had 1.951 times higher odds of testing positive for the other carbohydrate. CONCLUSIONS: Our results reveal a clinically significant association between fructose malabsorption and fructan malabsorption in patients with IBS. Fructan malabsorption should be assessed in patients with fructose malabsorption, and vice versa. Further studies are required to identify the mechanisms underlying our findings.

Integration in oncogenes plays only a minor role in determining the in vivo distribution of HIV integration sites before or during suppressive antiretroviral therapy.

HIV persists during antiretroviral therapy (ART) as integrated proviruses in cells descended from a small fraction of the CD4+ T cells infected prior to the initiation of ART. To better understand what controls HIV persistence and the distribution of integration sites (IS), we compared about 15,000 and 54,000 IS from individuals pre-ART and on ART, respectively, with approximately 395,000 IS from PBMC infected in vitro. The distribution of IS in vivo is quite similar to the distribution in PBMC, but modified by selection against proviruses in expressed genes, by selection for proviruses integrated into one of 7 specific genes, and by clonal expansion. Clones in which a provirus integrated in an oncogene contributed to cell survival comprised only a small fraction of the clones persisting in on ART. Mechanisms that do not involve the provirus, or its location in the host genome, are more important in determining which clones expand and persist.

Food elimination diet is a viable alternative therapy for eosinophilic esophagitis responsive to proton pump inhibitors.

BACKGROUND: First-line treatment of eosinophilic esophagitis (EoE) includes monotherapy with proton-pump inhibitors (PPIs), food elimination diet (FED), or topical corticosteroids. Current guidelines suggest patients with EoE should continue any responsive first-line monotherapies. However, the efficacy of FED monotherapy in patients with EoE responsive to PPI monotherapy has not been well studied. Our study aimed to investigate how attempting FED monotherapy after experiencing remission of EoE after PPI monotherapy influenced long-term EoE management. METHODS: We retrospectively identified patients with EoE responsive to PPI monotherapy who trialed FED monotherapy. We then employed a mixed method approach to a prospective cohort. Selected patients were observed long term for quantitative outcomes, while qualitative results were obtained from patient surveys regarding their perspectives on the trial of FED monotherapy. RESULTS: We identified 22 patients who trialed FED monotherapy after experiencing remission of EoE following PPI monotherapy. Of these 22 patients, 13 had remission of EoE with FED monotherapy, while 9 had re-activation of EoE. Out of 22 patients, 15 were enrolled in a cohort for observation. No exacerbations of EoE occurred while on maintenance treatment. Most patients stated that they would recommend this process to others with EoE (93.33%) and that trial of FED monotherapy helped them identify a treatment plan that aligned with their lifestyle (80%). CONCLUSION: Our work shows that FED monotherapy can be an effective alternative for patients with EoE responsive to PPI monotherapy that may improve patient quality of life, suggesting alternative treatment options should be considered for monotherapy-responsive EoE.

Identification and Characterization of a B-Raf Kinase α-Helix Critical for the Activity of MEK Kinase in MAPK Signaling.

In the MAPK pathway, an oncogenic V600E mutation in B-Raf kinase causes the enzyme to be constitutively active, leading to aberrantly high phosphorylation levels of its downstream effectors, MEK and ERK kinases. The V600E mutation in B-Raf accounts for more than half of all melanomas and ∼3% of all cancers, and many drugs target the ATP binding site of the enzyme for its inhibition. Because B-Raf can develop resistance against these drugs and such drugs can induce paradoxical activation, drugs that target allosteric sites are needed. To identify other potential drug targets, we generated and kinetically characterized an active form of B-RafV600E expressed using a bacterial expression system. In doing so, we identified an α-helix on B-Raf, found at the B-Raf-MEK interface, that is critical for their interaction and the oncogenic activity of B-RafV600E. We assessed the binding between B-Raf mutants and MEK using pull downs and biolayer interferometry and assessed phosphorylation levels of MEK in vitro and in cells as well as its downstream target ERK to show that mutating certain residues on this α-helix is detrimental to binding and downstream activity. Our results suggest that this B-Raf α-helix binding site on MEK could be a site to target for drug development to treat B-RafV600E-induced melanomas.

Dupilumab Can Induce Remission of Eosinophilic Gastritis and Duodenitis: A Retrospective Case Series.

INTRODUCTION: Noneosinophilic esophagitis eosinophilic gastrointestinal disorders (non-EoE-EGIDs) have limited treatment options to induce histologic and clinical remission. Dupilumab is a human monoclonal antibody against the interleukin-4 receptor ɑ subunit, which has been reported to induce improvement in pediatric patients with non-EoE-EGIDs. METHODS: We conducted a retrospective chart review to identify if patients with eosinophilic gastritis (EoG) and/or eosinophilic duodenitis (EoD) experience clinical and histologic remission with dupilumab. RESULTS: Twelve patients were included (2 patients with EoG and EoD, 3 patients with EoG only, and 7 patients with EoD only). All patients experienced improvement of at least 1 symptom on dupilumab, 3 patients (25%) had no change in severity of 1 or more of their symptoms, and no patients had worsening symptoms. On dupilumab, 2 patients with EoG (40%) and 3 patients with EoD (33.3%) were completely asymptomatic. Histologic changes were investigated in a subanalysis including 8 patients (2 patients with EoG and EoD, 2 patients with EoG only, and 4 patients with EoD only). Median peak gastric eosinophil counts in patients with EoG reduced from 80.5 eos/hpf (min-max 32-150, Q1-Q3 45.5-111) to 7.5 eos/hpf (min-max 0-28, Q1-Q3 1.5-16.8). Median peak duodenal eosinophil counts in patients with EoD reduced from 39 eos/hpf (min-max 30-50, Q1-Q3 37.3-46.3) to 16.5 eos/hpf (min-max 0-50, Q1-Q3 8-38.5). All 4 patients (100%) with EoG and 4 patients (66.6%) with EoD had histologic remission on dupilumab. DISCUSSION: In this retrospective case series, we showed preliminary evidence that dupilumab may be effective in inducing histologic and symptomatic remission in patients with non-EoE-EGIDs.

Asymptomatic Systemic Mastocytosis Uncovered During Routine Colonoscopy: A Case Report.

We report an atypical case of systemic mastocytosis in a 66-year-old asymptomatic female, diagnosed incidentally during a routine colonoscopy. This case highlights the diversity of clinical presentations and emphasizes the role of colonoscopy and the need for thorough histopathological examinations in routine endoscopic procedures with subtle abnormalities.

Increases in local skin temperature correlate with spontaneous foot lifting and heat hyperalgesia in both incisional inflammatory models of pain.

Background: This study investigated if a localized increase in skin temperature in rat models of incisional and inflammatory pain correlates with the intensity of spontaneous and evoked pain behaviors. Methods: Anesthetized rats received either a 20-mm longitudinal incision made through the skin, fascia, and muscle of the plantar hind paw or an injection of complete Freund adjuvant into the plantar hind paw of anesthetized rats to induce local inflammation. Spontaneous and evoked pain behaviors were assessed, and changes in skin temperature were measured using a noncontact infrared thermometer. Results: There were no differences in skin temperature between the ipsilateral and contralateral hind paw before the incision or inflammation. Skin temperature increased at 2 hours after hind paw plantar incision or 1 day after inflammation of the affected paw, which gradually returned to baseline by the first day and fourth days after treatment, respectively. The increase in skin temperature correlated with the intensity of spontaneous pain behaviors and heat but not with mechanical allodynia. Conclusions: Our results suggest that a simple measurement of localized skin temperature using a noncontact infrared thermometer could measure the extent of spontaneous pain behaviors and heat hyperalgesia following plantar incision or inflammation in animals. In the absence of a reliable objective marker of pain, these results are encouraging. However, studies are warranted to validate our results using analgesics and pain-relieving interventions, such as nerve block on skin temperature changes.

Elevated Total Serum Immunoglobulin A Levels in Patients with Suspicion for Celiac Disease.

Patients with classic symptoms of celiac disease are often initially tested for serum tissue transglutaminase-immunoglobulin A (tTG-IgA) and total serum immunoglobulin A (IgA) levels concurrently, as IgA deficiency can lead to falsely low tTG-IgA. There are no guidelines for incidental findings of elevated total serum IgA when testing for celiac disease. In our study, we described the proportion of patients with suspicion of celiac disease who had elevated total serum IgA and the factors that may be associated with these findings. We studied the management of these patients with incidental findings of elevated total serum IgA to identify its clinical significance. To investigate, we performed a retrospective chart review of patients who underwent celiac disease serologic testing at a single clinic from January 2017 to June 2022. We reported further laboratory workup and follow-up for patients with incidental findings of elevated total serum IgA by board-certified immunologists. In our chart review, 848 patients were identified, 85 (10.0%) of whom were found to be negative for celiac disease but had elevated total serum IgA levels (median IgA 351 mg/dL, interquartile range 324-382). Out of 85 patients, 73 were further evaluated by immunologists, with 55 patients undergoing additional laboratory workup. None were diagnosed with specific immunologic conditions. Male sex was identified as associated with elevated total serum IgA findings, and constipation was found in a statistically significant greater frequency of patients with normal total serum IgA rather than elevated total serum IgA. To provide external validation of our findings, we created a second patient cohort within the Stanford Research Repository database. Out of 33,875 patients identified, a similarly high proportion of patients were negative for celiac disease but had elevated total serum IgA levels (9.3%, 3140 patients). In this separate patient cohort, male sex was also identified as being associated with elevated total serum IgA. Our study also provides preliminary evidence that patients with incidental findings of elevated total serum IgA may not need further management or workup, as these abnormalities may not be clinically relevant without other clinical suspicions.

Combination of Proton Pump Inhibitors and Food Elimination Diet for Eosinophilic Esophagitis Refractory to Monotherapy.

Background and Aims: Eosinophilic esophagitis (EoE) is an antigen-mediated inflammatory esophageal disease that is commonly treated with high-dose proton-pump inhibitors (PPIs), topical corticosteroids, or food elimination diet (FED) monotherapy. Combination treatment has not been well studied in the management of EoE. We aimed to determine if PPI and FED combination therapy was able to induce histologic remission in patients with EoE refractory to monotherapy. Methods: We conducted a retrospective cohort study identifying patients with EoE that was refractory to PPI monotherapy and FED monotherapy but histologically responsive to PPI and FED combination therapy. We also identified symptom changes through chart review. Results: Out of 405 EoE patients, 12 patients were identified with EoE that was refractory to PPI monotherapy and FED monotherapy but histologically responsive to PPI and FED combination therapy. Out of 12 patients, 11 (91.67%) noted resolution of symptoms while on combination therapy. Comparative analysis of peak eosinophil counts showed that patients achieved a median of 4.5 eos/hpf (interquartile range [IQR], 2-6.5), which was significantly decreased compared to baseline (median, 45; IQR, 35.5-50; Wilcoxon signed-rank test, P < .001), PPI monotherapy (median, 41; IQR, 26-50; Wilcoxon signed-rank test, P < .001), and FED monotherapy (median, 45; IQR, 17-67.5; Wilcoxon signed-rank test, P < .001). Conclusion: Our work shows that patients with EoE refractory to PPI monotherapy and FED monotherapy can successfully achieve histologic remission and symptom benefit with PPI and FED combination therapy. Therefore, combination therapy should be considered a viable option for patients with EoE who fail treatment with first-line monotherapies.