The human ileocaecal junction: anatomical evidence of a sphincter

Can AnatomicalTerms.info with its synonyms and succinct open definitions be a solution to address variations in usage of anatomical terminology?

Anatomy, the study of human structure, is foundational to medicine. Its language has a long history, with contributions from authors hailing from diverse cultures and countries, adhering to various scientific traditions, speaking different languages, and practicing medicine across a wide gamut of specialties. The resultant disparity in terms provides challenges both for students in learning and for interdisciplinary communication. We report here on a user-friendly look-up web site, "AnatomicalTerms.info" that links a Terminologica Anatomica term to alternative terms in usage: synonyms, polysemes, eponyms, homonyms, and terms in other languages. Accompanying open-source definitions are generated with the help of "Definition Machine" software, that supports creating the most concise and accessible definitions for anatomical terms, eschewing superfluous description, thus reducing cognitive load of learners of anatomy looking up terms. AnatomicalTerms.info is a readily accessible online source for both the authoritative and alternatively used terms that can accurately cross-reference and/or disambiguate anatomical structures across disciplinary and cultural divides. As such, it can serve as a useful educational and clinical resource that is also flexibly open to additions and expansion as anatomical and clinical needs dictate.

Assessment of Anatomical Morphology of the Ileocecal Junction and Ileocecal Valve by Dissection and Endoscopy

INTRODUCTION

The ileocecal valve (ICV) guards the opening of the ileocecal junction (ICJ) and acts as a mechanical barrier to prevent the reflux of material from the colon into the ileum. The morphology of the ICV noted in living is different from that of cadavers. The ICV is better studied in the living by endoscopy. A study of variation in the gross anatomy of the ICV can help determine the factors responsible for its competency.

MATERIALS AND METHODS

A descriptive study was conducted on a total of 85 (N) patients each in two groups over a period of two years. Group I: 85 specimens of the ileocecal region obtained during dissection; Group 2: 85 patients undergoing colonoscopic study undertaken in the Department of Medical Gastroenterology. In the dissection method, the apparently normal ICJ was inspected, photographed, and measured using Vernier calipers. In the colonoscopy method, the procedure was observed and while observing ICV, photos were taken. These photographs were later compared with other photographs in the literature to identify the morphology of ICV. The age, gender, location, and morphology of ICV were represented in percentile, and qualitative variables were analyzed by Pearson correlation coefficient.

RESULTS

Out of 85 participants in Group A, 80% (68) were males and 20% (17) were females; in Group B, 58% (49) were males, and the remaining 42% (36) were females. In the dissection method out of 85 (N) patients, 98% had reverse S type terminal ileum, correlation of diameter of ICV with age p=0.003 and correlation of morphology of ICV with age p=0.006, and was statistically significant. In the colonoscopy method, 58% were males and 22% of them were 31-40 years. In 49% of patients, ICV was viewed from the left lateral position. The correlation of success of ileoscopy with age (p=0.608), gender (p=0.896), the position of the patient (p=0.236), and morphology of ICV (p=0.631) was not statistically significant.

CONCLUSION

There were no age-related changes observed regarding the morphology of the ICJ. It was found that as age increases diameter of ICV increases. The success of ileoscopy was highest in 31-40 years of age.

Tension Pneumoperitoneum as a Result of Diastatic Perforation

Tension pneumoperitoneum is a vapid presentation of pneumoperitoneum, which generally refers to free air in the abdomen and can mimic abdominal compartment syndrome. A diastatic perforation in the abdomen refers to a perforation of the cecum due to a distal obstruction in the colon, manifesting as a closed-loop syndrome. We present a 46-year-old male diagnosed with obstructed left inguinal hernia who underwent hernioplasty. Postoperatively, the patient had progressive abdominal distention and abdominal pain. An abdominal x-ray and computed tomography of the abdomen showed massive air in the abdomen. The patient was diagnosed to have tension pneumoperitoneum. Needle decompression of the abdomen was done, and the patient underwent an emergency laparotomy. Intraoperatively, we found a large cecal perforation and a large amount of pneumoperitoneum. The patient underwent limited resection and ileostomy and ascending mucus fistula. Postoperatively, the patient had an uneventful course and was discharged.

Spatial dynamics of inflammation-causing and commensal bacteria in the gastrointestinal tract

In recent years, new research programmes have been initiated to understand the role of gut bacteria in health and disease, enabled in large part by the emergence of high-throughput sequencing. As new genomic and other data emerge it will become important to explain observations in terms of underlying population mechanisms; for instance, it is of interest to understand how resident bacteria interact with their hosts and pathogens, and how they play a protective role. Connecting underlying processes with observed patterns is aided by the development of mathematical models. Here, we develop a spatial model of microbial populations in the gastrointestinal tract to explore conditions under which inflammation-causing bacteria can invade the gut and under which such pathogens become persistent. We find that pathogens invade both small and large intestine from even a relatively small inoculum size but are usually eliminated by the host response. When the immune response is weak, the pathogen is able to persist for a long period. Spatial structure affects these dynamics by creating moving refugia which facilitate bouts of pathogen resurgence and inflammation in persistent infections. Space also plays a role in repopulation by commensals after infection. We further find that the rate of decay of inflammation has a stronger effect on outcomes than the initiation of inflammation or other parameters. Finally, we explore the impact of partially inflammation-resistant commensals on these dynamics.

Fabrici and the functional power of the image

Hieronymus Fabricius ab Acquapendente, famous anatomist of the medical school of Padua, Italy, marked a further step not only in the morphological studies, but also in anatomical illustration and physiology. His researches were inspired by the work of Aristotle which was focused on the understanding of biological "functions" in an anatomo-comparative way. The anatomo-comparative approach of Fabrici allowed him to discover several specific features of human anatomy. His focusing on function marked the transition from a descriptive to a functional anatomy, paving the way to the birth of human physiology in the following century. To enhance the teaching and learning of anatomy, Fabrici realized the importance of the "dimension" and "color" of anatomical illustrations and introduced for first full-scale and colour painted plates. In this way, the images were closer to representing "living" parts, than previous black & white and low scale images. Moreover, Fabrici was the first to create an "anatomo-phisiological" image, namely the one representing the valves in the veins. His work was a fundamental inspiration for his students, in particular Gaspard Bauhin and William Harvey.

Investigation of Novel c-Kit-expressing Smooth Muscle Cells in Murine Cecum

In the gastrointestinal tract musculatures, c-Kit receptor tyrosine kinase is specifically expressed in interstitial cells of Cajal (ICC). ICC are distributed among the smooth muscle cells and are either bipolar or multipolar in shape. Our previous and current study shows that c-Kit-immunopositive smooth muscle cells are present in the murine cecum. Here, we found that c-Kit-expressing smooth muscle cells (named Kit-SM cells) are situated at the submucosal surface of the circular muscle layer. These cells showed smooth muscle actin and myosin immunoreactivities and ultrastructural features such as thick and thin filaments and caveolae. Kit-SM cells also expressed TMEM16A and LRIG1, which are known to be expressed in ICC. Although the functional significance of Kit-SM cells has yet to be revealed, these cells can be considered to have proliferation or differentiation potential in the cecal musculature.

Subtotal colectomy with antiperistaltic cecosigmoidal anastomosis may be another suitable option for slow transit constipation: Experiences from Chinese people

The objective of this paper is to demonstrate, considering the experiences from Chinese people, if slow transit constipation (STC) can be accurately diagnosed, choosing patients qualifying for surgery, subtotal colectomy with antiperistaltic cecosigmoidal anastomosis (STC-Anti-CSA) may come with more acceptable short and long-term outcomes.A retrospective study was performed at a department of colorectal and anal surgery. A cohort of 29 patients were coming with up to 5 years' follow-up care, who were in a diverse range of age, BMI, laxative medicine histories, including both males and females. Pre-surgery work-up strictly followed a protocol designed to rule out the patients who were not suitable for surgery treatments. Classification of STC was followed after diagnosis. STC-Anti-CSA was performed in all cases. The operative time, blood loss, average post-operative length of stay (LOS), frequency of BMs, stool consistency and patients satisfaction, by using Wexner constipation score (WCS), numerical rating scale (NRS), and abdominal bloating score (ABS), over the study period were recorded.In this study, there were 14 males and 15 females, with mean age 51, and BMI from 20.14 to 31.62 kg/m. The period of laxative medicine history was 4.8 years (2-13 years). The mean operative time was 152 ± 34 min, and the mean perioperative blood loss was 123 ± 51 mL. Average post-operative LOS (LOS) was 8 days. There were no severe post-operative complications, peri-operative mortality, anastomotic leaks, or revisions of the original surgery. Initial post-operative BMs averaged 6 times/day. During the period of 1 month to 12 months follow-up care, BMs fell down to 2 or 3 times/day. By the 1st to 3rd year follow-up care, BMs averaged 5 to 7 times/week. However, from the 4th year to 5th year, constipations recurred somehow. However, most patients were satisfied with their bowel patterns.STC-Anti-CSA can receive acceptable postoperative outcomes as long as the patients can be accurately diagnosed and classified as severe STC. Among the surgical procedures for STC, this procedure may be another suitable option, especially for Chinese people.

The feasibility of laparoscopic subtotal colectomy with cecorectal anastomosis in community practice for slow transit constipation

BACKGROUND

The objective of this paper is to demonstrate if slow transit constipation (STC) can be accurately diagnosed, selecting patients appropriate for surgery, and safely perform laparoscopic subtotal colectomy with cecorectal anastomosis (CRA) with acceptable short and long-term outcomes in the setting of medically complex patients in a community practice.

METHODS

A retrospective study was performed at a private community surgical practice. Cohort involved 10 patients with up to 10 years in follow-up care with a diverse range of ages, body mass index (BMI) and medical conditions. Pre-operative work-up followed a comprehensive algorithm designed to rule out organic conditions and dyssynergistic defecation. The Sitz Mark Colon Transit Study was used to confirm STC. Laparoscopic subtotal colectomy with CRA techniques were used in all cases. Frequency of BMs and patient satisfaction over the study period were tabulated.

RESULTS

Average post-operative length of stay (LOS) was five days. One early major post-operative complication occurred, however there were no perioperative deaths, anastomotic leaks or revisions of the original surgery after discharge from the hospital. Two patients died due to non-bowel related causes. An incisional hernia was the single long-term complication. Initial post-operative BMs averaged several per day. In the 1-5 year follow-up, BMs tapered down from 1 to 2/day with some laxative use. By the 5th to 10th year follow-up, constipation occurred with 2-3 BMs/week, all requiring an osmotic laxative. Most patients, however, were satisfied with their bowel pattern.

CONCLUSION

Surgical candidates with severe STC can be accurately diagnosed and treated with minimally invasive surgery in community practice with acceptable outcomes as compared to outcomes published in the literature.

Morphogenesis and motility of the Astyanax mexicanus gastrointestinal tract

Through the course of evolution, the gastrointestinal (GI) tract has been modified to maximize nutrient absorption, forming specialized segments that are morphologically and functionally distinct. Here we show that the GI tract of the Mexican tetra, Astyanax mexicanus, has distinct regions, exhibiting differences in morphology, motility, and absorption. We found that A. mexicanus populations adapted for life in subterranean caves exhibit differences in the GI segments compared to those adapted to surface rivers. Cave-adapted fish exhibit bi-directional churning motility in the stomach region that is largely absent in river-adapted fish. We investigated how this motility pattern influences intestinal transit of powdered food and live prey. We found that powdered food is more readily emptied from the cavefish GI tract. In contrast, the transit of live rotifers from the stomach region to the midgut occurs more slowly in cavefish compared to surface fish, consistent with the presence of churning motility. Differences in intestinal motility and transit likely reflect adaptation to unique food sources available to post-larval A. mexicanus in the cave and river environments. We found that cavefish grow more quickly than surface fish when fed ad libitum, suggesting that altered GI function may aid in nutrient consumption or absorption. We did not observe differences in enteric neuron density or smooth muscle organization between cavefish and surface fish. Altered intestinal motility in cavefish could instead be due to changes in the activity or patterning of the enteric nervous system. Exploring this avenue will lead to a better understanding of how the GI tract evolves to maximize energy assimilation from novel food sources.

Effects of aging on the architecture of the ileocecal junction in rats

AIM: To evaluate the structural organization of the elastic and collagen fibers in the region of the ileocecal transition in 30 young and old male Wistar rats.

METHODS: Histology, immunohistochemistry (IHC), transmission electron microscopy and scanning electron microscopy were employed in this study. The results demonstrated that there was a demarcation of the ileocecal region between the ileum and the cecum in both groups.

RESULTS: The connective tissue fibers had different distribution patterns in the two groups. IHC revealed the presence of nitric oxide synthase, enteric neurons and smooth muscle fibers in the ileocecal junctions (ICJs) of both groups. Compared to the young group, the elderly group exhibited an increase in collagen type I fibers, a decrease in collagen type III fibers, a decreased linear density of oxytalan elastic fibers, and a greater linear density of elaunin and mature elastic fibers.

CONCLUSION: The results revealed changes in the patterns of distribution of collagen and elastic fibers that may lead to a possible decrease in ICJ functionality.