Endoluminal Techniques to Treat Obesity

The prevalence of overweight and obesity increased dramatically during the past decades and now affects approximately 30% of people worldwide. Bariatric surgery has proven to be the most effective treatment modality for obesity in the long term. However, current surgical procedures are accompanied by a substantial risk of complications. Several endoluminal techniques have been developed to achieve weight loss in obese patients and claim to be as effective as surgery but safer. This chapter evaluates the efficacy and safety of innovative endoluminal techniques that are already available in clinical practice or in advanced stages of development. This chapter outlines their potential mechanism of action and their safety and efficacy in clinical practice, by reviewing the current literature

The Diagnostic Accuracy of Serum Alpha-Fetoprotein Levels in Follow-up for Recurrence of Sacrococcygeal Teratoma; a Nationwide Review of SCT Cases in the Netherlands

Background: Serum alpha-fetoprotein (AFP) is often used as tumour marker for recurrent sacrococcygeal teratoma (SCT). We aimed to assess the normal dynamics of serum AFP levels after initial resection and diagnostic accuracy of serum AFP levels the follow-up for recurrence in SCT. Methods: This retrospective study included 57 patients treated for SCT in the six pediatric surgical centers in the Netherlands from 1980 to 2018. Main results: 57 patients were included in the study of whom 19 children developed 20 recurrences at a median of 14.0 months after initial resection. No significant difference was found in serum AFP level dynamics between the recurrence and non-recurrence group after initial resection (p = 0.950). Serum AFP levels did not significantly increase before recurrence (p = 0.106) compared to serum AFP levels of children without recurrence at the same time. However, serum AFP levels did significantly increase in malignant recurrences (n = 7) (p = 0.03) compared to patients without recurrence. A cut-off value of 55 μg/L was found to be predictive for recurrent SCT with an Area Under the Curve (AUC) of 0.636 with sensitivity of 50% and specificity of 100%. Conclusion: Dynamics of serum AFP levels are not different between patients with and without recurrence after initial resection of SCT. Serum AFP levels are not predictive for mature or immature recurrent SCT and normal AFP levels do not rule out recurrent SCT. However, serum AFP levels exceeding 55 μg/L can indicate recurrent SCT, especially malignant recurrences.</p

The Economics and Politics of Contracting out with the Private Sector: Evidence from the US Transit Industry

The paper studies contracting practices in the US transit industry. It employs the methods of transaction cost economics and public choice theory to develop an empirical model of bus contracting in the US transit industry. The empirical results shed light on why transit services in the US remain largely public, despite many attempts to introduce competition by contracting out services to the private sector. The results show that the decision by transit agencies to contract out with the private sector is constrained by the transaction costs of contracting and the institutional and subsidy arrangements that govern the transit industry in the US. Services that require idiosyncratic investments to provide large densities of passengers are less likely to be contracted out than those services that are provided using standard, small vehicles. Similarly, increases in federal subsidies and dedicated subsidies are found to discourage contracting out with the private sector. On the other hand, increases in state and local subsidies, other things being equal, encourage contracting. Agencies that have high labor costs –– indicating strong labor unions –– are less likely to contract out. In light of these findings, the paper concludes that piecemeal contracting out of services is not likely to increase the role of the private sector in the provision of public transit services. Structures of subsidies and federal arrangements creates intertwined incentives that discourage contracting by transit agencies, thus foiling the attempts to increase efficiencies by establishing competition for transit markets.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Scaling up contrast-enhanced micro-CT imaging:Optimizing contrast and acquisition for large ex-vivo human samples

Microfocus Computed Tomography (Micro-CT) is a novel method for non-destructive 3D imaging of samples, reaching microscale resolutions. While initially prominent in material sciences for small samples, micro-CT now gains significance in biological and medical studies. Here we present our utilization of micro-CT for imaging large ex-vivo human samples for anatomical and forensic research in three recent experiments and discuss the fundamentals of micro-CT imaging. For pelvic anatomical research, whole human pelvises were imaged to explore nerve anatomy around the prostate using various concentrations of buffered lugol (B-lugol). Advanced acquisition protocols were essential due to X-ray attenuation properties of the sample, which required higher energy for sufficient photon transmission. For fetal research, B-lugol stained fetuses of 20–24 gestational weeks underwent full body imaging. However, this led to challenging acquisition parameters and images of insufficient quality. Subsequent destaining yielded less dense, yet contrast-maintaining samples allowing higher quality images. Refined acquisition protocols with reduced energy improved image quality. For forensic research, explanted hyoid-larynx complexes were imaged. Micro-CT imaging showed potential in visualizing micro-fractures. The addition of B-lugol allowed for excellent soft tissue contrast and promising possibilities for forensic evaluation. In conclusion, micro-CT imaging accommodates a diversity of large ex-vivo human samples for anatomical and forensic purposes, though challenges arise with optimal soft tissue staining and acquisition protocols. We describe partial destaining as a new possibility to alleviate scanning issues to improve scan quality and highlight topics for future research. Micro-CT imaging is a promising new avenue for medical research and forensic evaluation.</p

Esophageal mucosal integrity improves after laparoscopic antireflux surgery in children with gastroesophageal reflux disease

Background: Esophageal intraluminal baseline impedance reflects the conductivity of the esophageal mucosa and may be an instrument for in vivo evaluation of mucosal integrity in children with gastroesophageal reflux disease (GERD). Laparoscopic antireflux surgery (LARS) is a well-established treatment option for children with proton pump inhibitory (PPI) therapy resistant GERD. The effect of LARS in children on baseline impedance has not been studied in detail. The aim of this study was to evaluate the effect of LARS on baseline impedance in children with GERD. Methods: This is a prospective, multicenter, nationwide cohort study (Dutch national trial registry: NTR2934) including 25 patients [12 males, median age 6 (range 2–18) years] with PPI-resistant GERD scheduled to undergo LARS. Twenty-four hour multichannel intraluminal impedance pH monitoring (MII-pH monitoring) was performed before and 3 months after LARS. Baseline impedance was evaluated during consecutive 2-h intervals in the 24-h tracings. Results: LARS reduced acid exposure time from 8.5 % (6.0–16.2 %) to 0.8 % (0.2–2.8 %), p < 0.001. Distal baseline impedance increased after LARS from 2445 Ω (1147–3277 Ω) to 3792 Ω (3087–4700 Ω), p < 0.001. Preoperative baseline impedance strongly correlated with acid exposure time (r −0.76, p < 0.001); however, no association between symptomatic outcome and baseline impedance was identified. Conclusions: LARS significantly increased baseline impedance likely reflecting recovery of mucosal integrity. As the change in baseline impedance was not associated with the clinical outcome of LARS, other factors besides mucosal integrity may contribute to symptom perception in children with GERD

Scaling up contrast-enhanced micro-CT imaging:Optimizing contrast and acquisition for large ex-vivo human samples

Microfocus Computed Tomography (Micro-CT) is a novel method for non-destructive 3D imaging of samples, reaching microscale resolutions. While initially prominent in material sciences for small samples, micro-CT now gains significance in biological and medical studies. Here we present our utilization of micro-CT for imaging large ex-vivo human samples for anatomical and forensic research in three recent experiments and discuss the fundamentals of micro-CT imaging. For pelvic anatomical research, whole human pelvises were imaged to explore nerve anatomy around the prostate using various concentrations of buffered lugol (B-lugol). Advanced acquisition protocols were essential due to X-ray attenuation properties of the sample, which required higher energy for sufficient photon transmission. For fetal research, B-lugol stained fetuses of 20–24 gestational weeks underwent full body imaging. However, this led to challenging acquisition parameters and images of insufficient quality. Subsequent destaining yielded less dense, yet contrast-maintaining samples allowing higher quality images. Refined acquisition protocols with reduced energy improved image quality. For forensic research, explanted hyoid-larynx complexes were imaged. Micro-CT imaging showed potential in visualizing micro-fractures. The addition of B-lugol allowed for excellent soft tissue contrast and promising possibilities for forensic evaluation. In conclusion, micro-CT imaging accommodates a diversity of large ex-vivo human samples for anatomical and forensic purposes, though challenges arise with optimal soft tissue staining and acquisition protocols. We describe partial destaining as a new possibility to alleviate scanning issues to improve scan quality and highlight topics for future research. Micro-CT imaging is a promising new avenue for medical research and forensic evaluation.</p