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How the dorsal-ventral axis of the vertebrate jaw, particularly the position of tooth initiation site, is established remains a critical and unresolved question. Tooth development starts with the formation of the dental lamina, a localized thickened strip within the maxillary and mandibular epithelium. To identify transcriptional regulatory networks (TRN) controlling the specification of dental lamina from the naïve mandibular epithelium, we utilized Laser Microdissection coupled low-input RNA-seq (LMD-RNA-seq) to profile gene expression of different domains of the mandibular epithelium along the dorsal-ventral axis. We comprehensively identified transcription factors (TFs) and signaling pathways that are differentially expressed along mandibular epithelial domains (including the dental lamina). Specifically, we found that the TFs Sox2 and Tfap2 (Tfap2a/Tfap2b) formed complimentary expression domains along the dorsal-ventral axis of the mandibular epithelium. Interestingly, both classic and novel dental lamina specific TFs-such as Pitx2, Ascl5 and Zfp536-were found to localize near the Sox2:Tfap2a/Tfap2b interface. To explore the functional significance of these domain specific TFs, we next examined loss-of-function mouse models of these domain specific TFs, including the dental lamina specific TF, Pitx2, and the ventral surface ectoderm specific TFs Tfap2a and Tfap2b. We found that disruption of domain specific TFs leads to an upregulation and expansion of the alternative domain's TRN. The importance of this cross-repression is evident by the ectopic expansion of Pitx2 and Sox2 positive dental lamina structure in Tfap2a/Tfap2b ectodermal double knockouts and the emergence of an ectopic tooth in the ventral surface ectoderm. Finally, we uncovered an unappreciated interface of mesenchymal SHH and WNT signaling pathways, at the site of tooth initiation, that were established by the epithelial domain specific TFs including Pitx2 and Tfap2a/Tfap2b. These results uncover a previously unknown molecular mechanism involving cross-repression of domain specific TFs including Pitx2 and Tfap2a/Tfap2b in patterning the dorsal-ventral axis of the mouse mandible, specifically the regulation of tooth initiation site.

This study develops and uses a survey to gather information on demographics, production and management practices, and perceptions on using cover crops as a conservation practice from citrus growers and utilizes the double-bounded dichotomous choice contingent valuation method to measure their willingness to pay (WTP) for adopting cover crops in citrus production. The survey is conducted for citrus producers in Florida and Texas. The study finds that, on average, growers from Florida are willing to pay $509.48/acre per year for adopting cover crops. This is substantially less than the WTP for growers in Texas, who are willing to pay more than $1,000/acre per year for cover crops. The study analyzes the factors that have significant impacts on growers’ WTP for cover crops and discusses the heterogeneity in the grower perceptions on the benefits and drawbacks of using this conservation practice by state. Although using cover crops has not been a popular conservation practice in perennial fruit production systems, its potential to improve soil quality is particularly important for citrus production in Florida where soils are sandy and have low organic matter.

Abstract Background Infants in the neonatal intensive care unit (NICU) are particularly susceptible to healthcare-associated infections (HAIs). NICUs in low- and middle income countries face additional challenges to HAI prevention. There is a need to better understand the role of the implementation context surrounding infection prevention interventions in low- and middle income countries. Aim The aim of this study was to identify NICU healthcare worker perceptions of an intervention to reduce bloodstream infections in a large Zambian NICU. Methods Semi-structured interviews were conducted with NICU staff during a prospective cohort study examining the impact of an infection prevention bundle on bloodstream infections. Interviews were analyzed using an integrated approach, combining inductive theme generation with an application of the Consolidated Framework for Implementation Research (CFIR). Results Interviews were conducted with 17 NICU staff (5 physicians and 12 nurses). Respondents believed the bundle elements were easy to use, well-designed and facilitated improved performance. Four organizational characteristics that facilitated HAI transmission were identified – (1) lack of NICU admission protocols; (2) physical crowding; (3) understaffing; and (4) equipment shortages. Respondents suggested that NICU resource constraints reflected a societal ethos that devalued the medical care of infants. Despite the challenges, respondents were highly motivated to prevent HAIs and believed this was an achievable goal. They enthusiastically welcomed the bundle but expressed serious concern about sustainability following the study. Conclusions By eliciting healthcare worker perceptions about the context surrounding an infection prevention intervention, our study identified key organizational and societal factors to inform implementation strategies to achieve sustained improvement.

Introduction: As fellowship training after general surgery residency has become increasingly common, the impact on resident education must be considered. Patient safety and procedure outcomes are often used as justification by attendings who favor fellows over residents in certain minimally invasive surgery (MIS) operations. The aim of the present study was to compare the impact of trainee level on the outcomes of selected MIS operations to determine if giving preference to fellows on grounds of outcomes is warranted., Methods: Patients who underwent elective laparoscopic hiatal hernia repair (LHHR), laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-en-Y gastric bypass (LRYGB), laparoscopic splenectomy (LS), laparoscopic cholecystectomy (LC), or laparoscopic ventral hernia repair (LVHR) with assistance of a general surgery chief resident or fellow were identified from the American College of Surgeon's National Surgical Quality Improvement Program database (2007-2012). Patients were matched 1:1 based on propensity score for the odds of undergoing operations assisted by a fellow., Results: 5145 patients underwent LHHR, 1396 LSG, 9656 LRYGB, 863 LS, 13,434 LC, and 3069 LVHR. Fellows assisted in 41.7% of LHHR, 49.2% of LSG, 56.4% of LRYGB, 25.7% of LS, 17.1% of LC, and 27.0% of LVHR cases. After matching, overall and severe complication rates were comparable between cases performed with assistance of a fellow or chief resident. Median operative time was longer for LSG, LRYGB, and LC when a fellow assisted., Conclusions: Surgical outcomes were similar between fellow and chief resident assistance in MIS operations, arguing that increased resident participation in basic and complex laparoscopic operations is appropriate without compromising patient safety., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: The Caprini risk assessment model is a well-validated tool that identifies patients who would benefit from extended venous thromboembolism (VTE) prophylaxis beyond hospital discharge. VTE, particularly portal mesenteric vein thrombosis (PMVT), is a potentially devastating complication of laparoscopic sleeve gastrectomy (LSG); therefore, we sought to examine whether the model can be safely applied to LSG patients. We hypothesized that its use can minimize the incidence of postoperative VTE, including PMVT, without increasing the likelihood of bleeding complications., Materials and Methods: We conducted a retrospective chart review of those patients who underwent LSG at our institution from 2010 and 2018, at which time the Caprini risk assessment model was already our institutional standard. We determined the patients' Caprini scores at the time of discharge and whether patients at high risk of VTE were discharged from hospital on extended courses of VTE prophylaxis. We also recorded if bleeding complications or VTE events occurred in the first 180 days after LSG., Results: Six hundred thirty-eight patients underwent LSG, including 521 (81.7%) women, with an average preoperative body mass index (BMI) of 44.4 kg/m 2 (SD 6.8). One hundred fifty-eight (24.8%) patients had Caprini scores that warranted extended courses of VTE prophylaxis beyond hospital discharge. Three patients (0.47%) developed a postoperative VTE, but no patient developed PMVT. No bleeding complications were observed among patients who received extended VTE prophylaxis., Conclusion: The Caprini risk assessment model can effectively identify patients after LSG who might benefit from extended courses of VTE prophylaxis. Extended VTE prophylaxis does not seem to confer increased bleeding risk in this patient population., (© 2021. The Society for Surgery of the Alimentary Tract.)

Importance: Bariatric surgical weight loss is associated with reduced cardiovascular mortality; however, the mechanisms underlying this association are incompletely understood., Objectives: To identify variables associated with vascular remodeling after bariatric surgery and to examine how sex, race, and metabolic status are associated with microvascular and macrovascular outcomes., Design, Setting, and Participants: This population-based longitudinal cohort included 307 individuals who underwent bariatric surgery. Participants were enrolled in the bariatric weight loss program at Boston Medical Center, a large, multi-ethnic urban hospital, with presurgical and postsurgical assessments. Data were collected from December 11, 2001 to August 27, 2019. Data were analyzed in September 2019., Exposure: Bariatric surgery., Main Outcomes and Measures: Flow-mediated dilation (FMD) and reactive hyperemia (RH) (as measures of macrovascular and microvascular function, respectively) and clinical variables were measured preoperatively at baseline and at least once postoperatively within 12 months of the bariatric intervention., Results: A total of 307 participants with obesity (mean [SD] age, 42 [12] years; 246 [80%] women; 199 [65%] White; mean [SD] body mass index, 46 [8]) were enrolled in this study. Bariatric surgery was associated with significant weight loss and improved macrovascular and microvascular function across subgroups of sex, race, and traditional metabolic syndrome (mean [SD] pre- vs postsurgery weight: 126 [25] kg vs 104 [25] kg; P < .001; mean [SD] pre- vs postsurgery FMD: 9.1% [5.3] vs 10.2% [5.1]; P < .001; mean [SD] pre- vs postsurgery RH: 764% [400] vs 923% [412]; P < .001). Factors associated with change in vascular phenotype correlated most strongly with adiposity markers and several metabolic variables depending on vascular territory (eg, association of weight change with change in RH: estimate, -3.2; 95% CI, -4.7 to -1.8; association of hemoglobin A1c with change in FMD: estimate, -0.5; 95% CI, -0.95 to -0.05). While changes in macrovascular function among individuals with metabolically healthy obesity were not observed, the addition of biomarker assessment using high-sensitivity C-reactive protein plasma levels greater than 2 mg/dL identified participants with seemingly metabolically healthy obesity who had low-grade inflammation and achieved microvascular benefit from weight loss surgery., Conclusions and Relevance: The findings of this study suggest that bariatric intervention is associated with weight loss and favorable remodeling of the vasculature among a wide range of individuals with cardiovascular risk. Moreover, differences in arterial responses to weight loss surgery by metabolic status were identified, underscoring heterogeneity in physiological responses to adiposity change and potential activation of distinct pathological pathways in clinical subgroups. As such, individuals with metabolically healthy obesity represent a mixed population that may benefit from more refined phenotypic classification.

Background: Ventral hernia repair is common in the expanding aging population, but remains challenging due to their frequent comorbidities. The purpose of this study is to compare the surgical outcomes of open vs. laparoscopic ventral hernia repair in elderly patients., Methods: Patients ≥ 65 years of age that underwent elective open or laparoscopic ventral hernia repair were identified from the American College of Surgeons National Surgical Quality Improvement Project (NSQIP) database. To reduce potential selection bias, propensity scores were created for the likelihood of undergoing laparoscopic surgery based on patients' demographics and comorbidities. Patients were matched based on the logit of the propensity scores. Thirty-day surgical outcomes were compared after matching using Chi-square test for categorical variables and the Wilcoxon Rank-Sum test for continuous variables., Results: 35,079 (71.1%) and 14,270 (28.9%) patients underwent open and laparoscopic ventral hernia repairs, respectively. Laparoscopic surgery was associated with a lower overall morbidity (5.9% vs. 9.1%; p < 0.001) compared to open repair. The incidence of surgical site infections (1.1% vs. 3.5%; p < 0.001), post-operative infections (2.7% vs. 3.6%; p < 0.001), and reoperation (1.7% vs. 2.1%; p = 0.009) were all lower after laparoscopic repair. All other major surgical outcomes were either better with laparoscopy or comparable between both treatment groups except for operative time., Conclusion: Although open surgery remains the most prevalent in the elderly population, the results of this study suggest that laparoscopic surgery is safe and associated with a lower risk of overall morbidity, surgical site infections, and reoperation.

Background: Roux-en-Y gastric bypass is a proven treatment for morbid obesity and its sequelae. Gastric bypass has a safe risk profile, but postoperative complications can be seen. We report on 10 cases of postoperative bleeding causing an obstructing clot at the jejunojejunostomy (JJ) occurring over a 9-year period., Objectives: The aim was to document presenting symptoms of obstructing clots at the JJ and to suggest a treatment approach to minimize complications., Setting: University Hospital, United States METHODS: The local Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database was queried for all patients undergoing reoperation after Roux-en-Y gastric bypass, from July 2009 until December 2019. All patients who were found to have postoperative bleeding causing an obstructing clot at the JJ were selected for retrospective medical-record review., Results: The most common presenting symptoms were Hematocrit drop (10 of 10), nausea (9 of 10), abdominal pain (7 of 10), and hematemesis (4 of 10). There were 12 reoperations in the 10 patients, 10 of which were completed laparoscopically. Infectious complications were the most frequent morbidity in our patients; 4 patients developed abscesses. In all of these, the operative notes described gross spillage into the peritoneal cavity. In later cases, the remnant stomach was decompressed before reoperation, reducing spillage., Conclusions: Despite the low rate of obstructing clots at the JJ, without rapid recognition and reoperation, there is a risk for serious complications. Typical presenting symptoms include nausea and abdominal pain, which help differentiate it from other causes of decreased hematocrit. Diagnosis is commonly made with computerized tomographic (CT) scan. Decompression of a dilated remnant stomach before addressing the clot can prevent intraperitoneal spillage and subsequent abscess formation. Enterotomy creation and removal of clot is recommended, without fear of continued bleeding., (Copyright © 2020 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Medical students increasingly report not feeling meaningfully involved during surgical clerkships. Preceptorship and mentorship through longitudinal experiences ameliorate this problem. A preceptorship model was introduced into the surgery clerkship at our institution to increase contact and improve relationships between students and faculty., Methods: The preceptorship model was introduced at select sites in 2017. In contrast to the standard structure in which students are assigned to cases and clinics as needed, preceptorship students are assigned to attending surgeons and follow the surgeons' schedules for the rotation. Student performance data, including final grades, clinical evaluations, and shelf examination scores, were collected for clerkship students from May 2017 to November 2018. Formative and summative evaluations for each student were collected. Qualitative content analysis was used to explore evaluations for themes., Results: Two hundred and seventy-four students completed the clerkship during the study period; 41 experienced a preceptorship model. There was no difference in student performance across clerkship structures. Summative and formative evaluations for preceptorship students were longer than for traditional students (137 words vs 78 words; p < 0.0001 and 46 words vs 16 words, p = 0.03 respectively). Preceptorship student evaluations contained higher-quality feedback relating to clerkship objectives than those of traditional students. Preceptorship comments also contained more frequent mentions of response to feedback., Conclusions: A preceptorship model was successfully implemented on the third-year surgical clerkship at our institution. Although there was no difference between top performers on either clerkship structure, preceptorship students received written evaluations with better feedback as a result of their direct relationship with faculty. Strategies such as this, which improve student-faculty relationships, will be needed as programs find new ways to assess residency applicants., (Copyright © 2020 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: The objective of this study was to evaluate the impact of resident involvement on surgical outcomes in laparoscopic compared to open procedures., Methods: The American College of Surgeons National Surgical Quality Improvement Program 2007-2012 was queried for open and laparoscopic ventral hernia repair (VHR), inguinal hernia repair (IHR), splenectomy, colectomy, or cholecystectomy (CCY). Multivariable regression analyses were performed to assess the impact of resident involvement on surgical outcomes., Results: In total, 88,337 VHR, 20,586 IHR, 59,254 colectomies, 3301 splenectomies, and 95,900 CCY were identified. Resident involvement was predictive for major complication during open VHR (AOR, 1.29; p < 0.001), but not during any other procedure. Resident participation significantly prolonged operative time for open, as well as laparoscopic VHR, IHR, colectomy, splenectomy, and CCY (all p < 0.01)., Conclusions: The results of this study suggest that resident participation has a similar impact on surgical outcomes during laparoscopic and open surgery, and is generally safe., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background Pathophysiological mechanisms that connect obesity to cardiovascular disease are incompletely understood. FSP27 (Fat-specific protein 27) is a lipid droplet-associated protein that regulates lipolysis and insulin sensitivity in adipocytes. We unexpectedly discovered extensive FSP27 expression in human endothelial cells that is downregulated in association with visceral obesity. We sought to examine the functional role of FSP27 in the control of vascular phenotype. Methods and Results We biopsied paired subcutaneous and visceral fat depots from 61 obese individuals (body mass index 44±8 kg/m 2 , age 48±4 years) during planned bariatric surgery. We characterized depot-specific FSP27 expression in relation to adipose tissue microvascular insulin resistance, endothelial function and angiogenesis, and examined differential effects of FSP27 modification on vascular function. We observed markedly reduced vasodilator and angiogenic capacity of microvessels isolated from the visceral compared with subcutaneous adipose depots. Recombinant FSP27 and/or adenoviral FSP27 overexpression in human tissue increased endothelial nitric oxide synthase phosphorylation and nitric oxide production, and rescued vasomotor and angiogenic dysfunction (P<0.05), while siRNA-mediated FSP27 knockdown had opposite effects. Mechanistically, we observed that FSP27 interacts with vascular endothelial growth factor-A and exerts robust regulatory control over its expression. Lastly, in a subset of subjects followed longitudinally for 12±3 months after their bariatric surgery, 30% weight loss improved metabolic parameters and increased angiogenic capacity that correlated positively with increased FSP27 expression (r=0.79, P<0.05). Conclusions Our data strongly support a key role and functional significance of FSP27 as a critical endogenous modulator of human microvascular function that has not been previously described. FSP27 may serve as a previously unrecognized regulator of arteriolar vasomotor capacity and angiogenesis which are pivotal in the pathogenesis of cardiometabolic diseases linked to obesity.

Background: Complications after gastric bypass (RYGB) are well documented. Reversal of RYGB is indicated in select cases but can lead to weight gain. Conversion from RYGB to sleeve gastrectomy (SG) has been proposed for correction of complications of RYGB without associated weight gain. However, little is known about outcomes after this procedure., Objectives: To examine outcomes after conversion from RYGB to SG., Setting: University hospital., Methods: A retrospective study of patients who underwent RYGB to SG conversion was undertaken., Results: Twelve patients underwent RYGB to SG conversion for refractory marginal ulceration, stricture, dumping, gastrogastric fistula, hypoglycemia, and failed weight loss. No deaths occurred. Four patients experienced 7 major complications, including portal vein thrombosis, bleeding, pancreatic leak, pulmonary embolus, seroma, anastomotic leak, and stricture. Two required reoperation, and 6 were readmitted within 30 days. Four required nasoenteric feeding postoperatively because of prolonged nausea. The complication of RYGB resolved in 11 of 12 patients. At 14.7 months, change in body mass index for all patients was a decrease of 2.2 kg/m(2). In 5 patients with morbid obesity at conversion, the change in body mass index was a decrease of 6.4 kg/m(2) at 19 months., Conclusions: Laparoscopic conversion from RYGB to SG is successful in resolving certain complications of RYGB and does not result in short-term weight gain. However, conversion has a high rate of major complications as well as a high rate of readmission and need for supplemental nutrition. Although conversion to SG may be appropriate in carefully-selected patients, other options for patients with severe chronic complications after RYGB should be considered., (Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Introduction: Vascular bullet embolism is a rare phenomenon with fewer than 200 cases reported in the literature., Presentation of Case: A 22 year-old male presented with a gunshot wound to the right lower quadrant. Imaging demonstrated a bullet lodged in his left lower quadrant. Upon operative exploration, a single hole was found in the right external iliac vein without injury into the left lower quadrant. The bullet was found to have migrated intravascularly from the right external to the left common iliac vein, and was subsequently removed endovascularly., Discussion: Bullet embolism occurs infrequently, with arterial more common than venous. Arterial embolization usually requires emergency operative intervention due to ischemia. While venous embolization is often asymptomatic, removal of the bullet is recommended to avoid delayed complications when possible., Conclusion: Venous bullet emboli should be removed endovascularly whenever technically possible., (Copyright © 2012 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.)

Background: Refractory Cushing disease (CD) is associated with considerable morbidity and mortality. Bilateral adrenalectomy (BA) offers effective permanent treatment. Both open and laparoscopic approaches have been used, but longterm comparisons are few., Study Design: We reviewed 40 consecutive BA for refractory CD from 1995 through 2007. Surgical results were evaluated. A Short Form-36 Quality-of-Life (QOL) survey was performed., Results: Eighty-five percent (34 of 40) of patients were women, and median age was 41.9 years (range, 22.2 to 78.3 years). All had persistent CD after transsphenoidal operation (mean, 1.7; range, 1 to 3). Median followup was 5.0 years. Thirty-eight percent (15 of 40) of procedures were performed laparoscopically; 1 was converted to open. There were no operative or 30-day mortalities, and there was 1 90-day mortality. Morbidities occurred in 7 of 40 (18%) patients. Median length of stay was shorter in the laparoscopic group (4 versus 6 days; p < 0.001). All patients achieved clinical reversal of hypercortisolism, including the 5 (13%) with ectopic adrenal tissue. Elevated serum ACTH (> 200 ng/mL) was present during followup in 33% (13 of 40). A QOL survey demonstrated 86% of patients felt good to excellent compared with 1 year pre-BA. Chronic fatigue was present most or all of the time in 46%, and patients were below population norms on 7 of 8 Short Form-36 scales. No difference was evident in QOL between laparoscopic and open adrenalectomy., Conclusions: Our experience demonstrates excellent survival and clinical results, despite the inherent risk in patients with CD. There are persistent fatigue and QOL deficits that are not ameliorated by laparoscopic compared with open resection.

In this discussion I have excluded consideration of the genetics of purely renal malformations, such as polycystic kidneys, and of functional disorders of the kidney. Systematic family studies are available for renal agenesis, duplication of the ureters, vesico-ureteric reflux (each probably due to maldevelopment of the ureteric bud), bladder exstrophy and hypospadias as isolated malformations. Renal agenesis has a birth frequency of about 1.2 in 10 000 and the proportion affected of sibs is about 3 per cent. Duplication of the ureter has a birth frequency of about 1 per cent and the proportion affected of sibs and parents of probands is about 12 per cent. Vesico-ureteral reflux also has a prevalence in early childhood of about 1 per cent and the proportion of sibs affected is about 10 per cent. Bladder exstrophy has a birth frequency of about 1 in 20 000 and perhaps about 1 per cent of sibs are affected. Hypospadias has a birth frequency in boys of about 1 in 300 and the proportion affected of brothers is about 10 per cent. Further family studies are needed of these malformations when they occur in isolation. Either the multifactorial threshold model or dominant inheritance with reduced penetrance and varied expressivity would fit the data available.

A family study of cleft lip, with or without cleft palate, was based on those treated by operation at The Hospital for Sick Children, London, between 1920 and 1939 in order to give information on the proportion affected of children and grandchildren. The probands were those who had survived, were successfully traced, and found to have had at least one child. Care was taken to exclude patients who were traced through a child, whether normal or affected, and not through the usual tracing procedure. Patients with recognised syndromes were also excluded. Because the series was based on patients who had survived and reproduced it was biased in favour of those with milder degrees of the malformation, and against those with any severe associated malformation. The proportion affected of children of probands was 3.15% (+/- 0.56), of sibs 2.79% (+/- 0.52), and of parents 1.18% (+/- 0.37), respectively. The lower proportion of parents affected is attributed to reduced reproductive fitness of patients born two generations ago. The proportion affected of nephews and nieces, aunts and uncles, and grandchildren was 0.47% (+/- 0.18), 0.59% (+/- 0.13), and 0.8% (+/- 0.6) respectively. The proportion affected of first cousins was 0.27% (+/- 0.08). The birth frequency of cleft lip (+/- cleft palate) is estimated to be about 0.1% in England. There were two first cousin and one second cousin marriages among the marriages of the parents. There was no increase of cleft palate among the relatives of the probands. The proportion of sibs affected increased with increasing severity of the malformation in the proband, where the proband was female, and where the proband had an affected parent or already had one affected sib. It was not, however, increased where a more remote relative was affected. The proportion of children affected was not increased when the proband had an affected parent or sib, but few families provided information. The most economical hypothesis to explain the findings is the multifactorial threshold model. The birth frequency of the malformation and the family patterns found make it improbable that one single mutant gene makes a major contribution to the liability to develop the condition.