Identifying Types of Neurons in the Human Colonic Enteric Nervous System.

Distinguishing and characterising the different classes of neurons that make up a neural circuit has been a long-term goal for many neuroscientists. The enteric nervous system is a large but moderately simple part of the nervous system. Enteric neurons in laboratory animals have been extensively characterised morphologically, electrophysiologically, by projections and immunohistochemically. However, studies of human enteric nervous system are less advanced despite the potential availability of tissue from elective surgery (with appropriate ethics permits). Recent studies using single cell sequencing have confirmed and extended the classification of enteric neurons in mice and human, but it is not clear whether an encompassing classification has been achieved. We present preliminary data on a means to distinguish classes of myenteric neurons in specimens of human colon combining immunohistochemical, morphological, projection and size data on single cells. A method to apply multiple layers of antisera to specimens was developed, allowing up to 12 markers to be characterised in individual neurons. Applied to multi-axonal Dogiel type II neurons, this approach demonstrated that they constitute fewer than 5% of myenteric neurons, are nearly all immunoreactive for choline acetyltransferase and tachykinins. Many express the calcium-binding proteins calbindin and calretinin and they are larger than average myenteric cells. This methodology provides a complementary approach to single-cell mRNA profiling to provide a comprehensive account of the types of myenteric neurons in the human colon.

Effects of per capita payments on governance: evidence from tribal casinos.

Some governments distribute profits from state-owned enterprises to citizens on a per capita basis while others do not. Does the use of per capita payments affect how governments trade off pro-economy policies with other constituent interests such as environmental quality and public health? We study that question in the context of tribal government decisions to close or keep open casinos on American Indian reservations during the COVID-19 pandemic. Relying on per capita payment data and administrative information on the operational status of over 200 tribal casinos, we investigate how the distribution of per capita payments relates to the number of days casinos were closed from February 2020 through February 2022. After controlling for casino size at the onset of COVID-19, as well as demographic, economic, and geographic characteristics of the reservations on which the casinos operate, we find that casinos governed by per capita payments remained open about 17-29% longer than other reservation-based casinos. That finding suggests that per capita payments create a pro-economy constituency and implies that the decision to pay dividends directly to citizens affects the sizes of revenues from state-owned enterprises, such as tribal-government-owned casinos, rather than merely determining how they are distributed.

Total colonic volvulus with a 720° twist of freely mobile colon.

Segmental colonic volvulus involving the sigmoid or ileocaecal region is an important cause of large bowel obstruction and a well-established surgical emergency. Volvulus of the entire colon however is hazardously rare, in which case the diagnosis is likely to be made intraoperatively. The surgeon is then faced with the conundrum of the best surgical management, especially in the case of early intervention with viable bowel. To our knowledge this has never been reported.

Sympathetic Pathways Target Cholinergic Neurons in the Human Colonic Myenteric Plexus.

Background: The sympathetic nervous system inhibits human colonic motility largely by effects on enteric neurons. Noradrenergic axons, which branch extensively in the myenteric plexus, are integral to this modulatory role, but whether they contact specific types of enteric neurons is unknown. The purpose of this study was to determine the association of noradrenergic varicosities with types of enteric neurons. Methods: Human colonic tissue from seven patients was fixed and dissected prior to multi-layer immunohistochemistry for human RNA binding proteins C and D (HuC/D) (pan-neuronal cell body labelling), tyrosine hydroxylase (TH, catecholaminergic labelling), Enkephalin (ENK), choline acetyltransferase (ChAT, cholinergic labelling) and/or nitric oxide synthase (NOS, nitrergic labelling) and imaged using confocal microscopy. TH-immunoreactive varicose nerve endings and myenteric cell bodies were reconstructed as three dimensional digital images. Data was exported to a purpose-built software package which quantified the density of varicosities close to the surface of each myenteric cell body. Results: TH-immunoreactive varicosities had a greater mean density within 1 µm of the surface of ChAT +/NOS- nerve cell bodies compared with ChAT-/NOS + cell bodies. Similarly, ENK-immunoreactive varicosities also had a greater mean density close to ChAT +/NOS- cell bodies compared with ChAT-/NOS + cells. Conclusion: A method for quantifying close associations between varicosities and nerve cell bodies was developed. Sympathetic axons in the myenteric plexus preferentially target cholinergic excitatory cells compared to nitrergic neurons (which are largely inhibitory). This connectivity is likely to be involved in inhibitory modulation of human colonic motility by the sympathetic nervous system.

Wolves make roadways safer, generating large economic returns to predator conservation.

Recent studies uncover cascading ecological effects resulting from removing and reintroducing predators into a landscape, but little is known about effects on human lives and property. We quantify the effects of restoring wolf populations by evaluating their influence on deer-vehicle collisions (DVCs) in Wisconsin. We show that, for the average county, wolf entry reduced DVCs by 24%, yielding an economic benefit that is 63 times greater than the costs of verified wolf predation on livestock. Most of the reduction is due to a behavioral response of deer to wolves rather than through a deer population decline from wolf predation. This finding supports ecological research emphasizing the role of predators in creating a "landscape of fear." It suggests wolves control economic damages from overabundant deer in ways that human deer hunters cannot.

Postoperative ileus-An ongoing conundrum.

BACKGROUND: Postoperative ileus is common and is a major clinical problem. It has been widely studied in patients and in experimental models in laboratory animals. A wide variety of treatments have been tested to prevent or modify the course of this disorder. PURPOSE: This review draws together information on animal studies of ileus with studies on human patients. It summarizes some of the conceptual advances made in understanding the mechanisms that underlie paralytic ileus. The treatments that have been tested in human subjects (both pharmacological and non-pharmacological) and their efficacy are summarized and graded consistent with current clinical guidelines. The review is not intended to provide a comprehensive overview of ileus, but rather a general understanding of the major clinical problems associated with it, how animal models have been useful to elucidate key mechanisms and, finally, some perspectives from both scientists and clinicians as to how we may move forward with this debilitating yet common condition.

The importance of wearing a seatbelt correctly - A case report of blunt trauma causing complete shearing transection of the gastroduodenal junction.

INTRODUCTION: Global mortality as a result of road traffic accidents (RTA) has reduced significantly since mandatory implementation of seatbelts. Whilst seatbelt related injury, or "seatbelt syndrome," is a recognised phenomenon, unrestrained passengers have considerably worse survival outcomes. Improper positioning of seatbelts, as is discussed in the following case, can cause extensive injury. PRESENTATION OF CASE: Our patient is a 35-year-old female who was a restrained front seat passenger in a car vs. tree collision at 80 km/h. Her seat belt was worn with the shoulder strap under her left axilla. She sustained multiple injuries including complete transection of the gastroduodenal junction. In addition to this she had splenic, liver, transverse colonic, left lower rib and humeral injury. She underwent damage control laparotomy with splenectomy; re-look with gastrojejunostomy and transverse colonic resection with defunctioning ileostomy. She made a good recovery and was discharged after a 4 week admission. DISCUSSION: Improperly worn seatbelts redistribute decelerative forces to sensitive regions. A multidisciplinary approach is required to effectively manage complex multi-system trauma. In trauma the simplest reconstructive measures can be the most effective and minimise risk of further complications for the patient. CONCLUSION: Improperly worn seatbelts pose a significant risk to patients. A traumatic complete gastroduodenal transection can be effectively reconstructed with gastrojejunostomy anastomosis.

Patient Satisfaction in Emergency General Surgery: A Prospective Cross-Sectional Study.

BACKGROUND: The importance of the patient experience is increasingly being recognised. However, there is a dearth of studies regarding factors affecting patient-reported outcomes in emergency general surgery (EGS), including none from the Southern Hemisphere. We aim to prospectively assess factors associated with patient satisfaction in this setting. METHODS: In this prospective cross-sectional study, all consecutive adult patients admitted to an acute surgical unit over four weeks were invited to complete a validated Patient-Reported Experience Measures questionnaire. These were completed either in person when discharge was imminent or by telephone <4 weeks post-discharge. Responses were used to determine factors associated with overall patient satisfaction. RESULTS: From 146 eligible patients, 100 (68%) completed the questionnaire, with a mean overall satisfaction score of 8.3/10. On multivariate analyses, eight factors were significantly associated with increased overall satisfaction. Five of these were similar to those previously prescribed by other like studies, being patient age >50 years, sufficient analgesia, satisfaction with the level of senior medical staff, important questions answered by nurses and confidence in decisions made about treatment. Three identified factors were new: sufficient privacy in the emergency department, sufficient notice prior to discharge and feeling well looked after in hospital. CONCLUSIONS: Factors associated with patient satisfaction were identified at multiple points of the patient journey. While some of these have been reported in similar studies, most differed. Hospitals should assess factors valued by their EGS population prior to implementing initiatives to improve patient satisfaction.

Complete resection of a massive mesenteric lymphangioma in an adult.

Mesenteric lymphangioma is a benign cystic tumour of the lymphatic vessels that occurs rarely in adults. Due to the infrequency of cases and the insidious presentation, these tumours can be diagnosed late and become massive. Resection of mesenteric lymphangioma in its entirety is the recommended management in order to prevent recurrence. This case report describes the finding of a massive mesenteric lymphangioma (dimensions 420×470×100 mm) in a young man, the investigations leading to diagnosis, and the subsequent surgical management. The substantial size of this tumour produced considerable challenges for the surgical team, including involvement of adjacent small bowel and mesenteric vasculature. Preoperative diagnosis and assessment of the anatomy was pivotal in achieving a complete resection and a good patient outcome.

Long-Term Outcomes Following Laparoscopic Repair of Large Hiatus Hernias Performed by Trainees Versus Consultant Surgeons.

BACKGROUND: The laparoscopic approach is the preferred method for repair of large hiatus hernias but can be technically challenging. Training surgeons need experience as the primary operator to gain competency in this operation. However, learning the procedure should not compromise the functional long-term outcome for patients. The aim of this study was to determine whether any difference in long-term outcomes exists for patients having a laparoscopic large hiatus hernia repair performed by a trainee versus a consultant surgeon. METHODS: A total of 648 suitable patients who had undergone laparoscopic repair of a large hiatus hernia were identified from a prospective database. Cases were divided into two groups based on whether the primary operator was a trainee or a consultant surgeon. Demographics, perioperative data, revisions and patient-reported clinical outcomes via standardised questionnaires were compared. RESULTS: There were no statistically significant differences in the clinical outcomes for patients undergoing laparoscopic repair of a large hiatus hernia performed by a trainee versus a consultant surgeon, with comparable patient-reported outcomes for heartburn, dysphagia, and overall satisfaction with the outcome following surgery. Median operative time was approximately 20 min longer for trainees (p = <0.0001). Revisional surgery rates were similar for the two groups. CONCLUSIONS: Patients operated on by trainees have equivalent long-term clinical outcomes to patients operated on by consultant surgeons. For these patients, surgery can be safely performed by supervised trainees.