Analysis of glycoconjugates and morphological characterization of the descending colon and rectum of the plains viscacha, Lagostomus maximus.

Herbivores exhibit specializations at the intestinal level that facilitate the bacterial fermentation. The available information on the digestive physiology of Lagostomus maximus makes this rodent an interesting model to evaluate morpho-functional adaptations to herbivory. The general objective of this work was centered on the study of the morphology and histochemistry of the descending colon and rectum of L. maximus. To do so, a comparative analysis of the morphology, ultrastructure and glycosylation pattern of both anatomical regions was carried out. Histochemical results revealed that in both sectors of the large intestine, there are goblet cells with different glycosylation pattern within a morphologically homogeneous cell population. The main difference between both intestinal segments lay in the fact that the most distal region of the large intestine showed a greater proportion of sialomucins, characterized by being slightly O-acetylated. Further specific differences were revealed by lectin histochemistry. These data allowed to perform a functional interpretation of the cell types and secreted substances, thus contributing to a better understanding of the role of mucins in the intestinal tract functioning.

The length of the large intestine in children determined by computed tomography scan.

Little information is available on the length of the normal large intestine and its component parts in children. This information would be useful for procedures such as colonoscopy. The aim of this study was to investigate the length of the large intestine and its component parts in New Zealand children. Archival deidentified pediatric supine abdominopelvic computed tomography (CT) scans were retrospectively analyzed. After exclusion criteria, a total of 112 scans (57 males and 55 females) were included in the study and divided into three age groups: 0-2 years (n = 33), 4-6 years (n = 40), and 9-11 years of age (n = 39). The length of the large bowel increased from a mean of 52 cm in children aged <2 years to 73 cm at 4-6 years and 95 cm at 9-11 years. In all age groups, the transverse colon was the longest segment, contributing ∼30% of the total length of the large bowel. In comparison to total large bowel length, the mean proportional length of the rectum (9-12%), sigmoid colon (23-27%), descending colon (19-22%), transverse colon (27-32%), and ascending colon (14-17%) varied little between the three age groups. There were no significant differences between males and females in all age groups. The cecum was located in the right upper quadrant in 27% of children aged 0-2 years but in the right lower quadrant in all 9-11 year olds. These data provide useful information on the length of the large intestine and its component parts in living children, which are particularly relevant to pediatric colonoscopy and surgery. Clin. Anat. 30:887-893, 2017. © 2017 Wiley Periodicals, Inc.

Submucosal lipoma simulating a malignant tumor of the left colon: a case report / Lipoma submucoso simulando tumor maligno de cólon esquerdo: relato de caso

Intestinal lipomas can occur anywhere in the gastrointestinal tract, and these tumors are more frequent in the colon. By being largely asymptomatic, colonic lipomas are usually found incidentally, as findings in colonoscopy examinations, in association with biopsy. Endoscopic or surgical resection is the therapeutic option, depending on the size of the tumor, its location, and the presence or absence of symptoms. In this study, we present a case of a 59-year old woman, with a descending colon lipoma histologically diagnosed only after surgical resection of the lesion. The approach was adopted according to the patient's clinical picture (intestinal bleeding, vomiting and weight loss), in addition to the occlusion of 80% of the colonic lumen observed in a colonoscopy.

Os lipomas intestinais podem ocorrer em qualquer parte do trato gastrointestinal, sendo mais frequente no cólon. Por serem em grande parte assintomáticos, os lipomas colônicos são usualmente encontrados acidentalmente como achados de exame de colonoscopia associada à biópsia. Como opções de tratamento, há a ressecção endoscópica ou cirúrgica, a depender do tamanho do tumor, sua localização e presença (ou não) de sintomas. Nesse relato, é apresentado um caso de uma mulher de 59 anos com lipoma de cólon descendente, diagnosticado histologicamente apenas após ressecção cirúrgica da lesão. A conduta foi adotada pelo quadro clínico de enterorragia, vômitos e perda ponderal, além da oclusão de 80% da luz do cólon observada em exame de colonoscopia.

Dynamic article: surgical anatomical planes for complete mesocolic excision and applied vascular anatomy of the right colon.

BACKGROUND: Lower local recurrence rates and better overall survival are associated with complete mesocolic excision with central vascular ligation for treatment of colon cancer. To accomplish this, surgeons need to pay special attention to the surgical anatomical planes and vascular anatomy of the colon. However, surgical education in this area has been neglected. OBJECTIVE: The aim of this study is to define the correct surgical anatomical planes for complete mesocolic excision with central vascular ligation and to demonstrate the correct dissection technique for protecting anatomical structures. DESIGN AND SETTINGS: Macroscopic and microscopic surgical dissections were performed on 12 cadavers in the anatomy laboratory and on autopsy specimens. The dissections were recorded as video clips. METHODS: Dissections were performed in accordance with the complete mesocolic excision technique on 10 male and 2 female cadavers. Vascular structures, autonomic nerves, and related fascias were shown. Within each step of the surgical procedure, important anatomical structures were displayed on still images captured from videos by animations. RESULTS: Three crucial steps for complete mesocolic excision with central vascular ligation are demonstrated on the cadavers: 1) full mobilization of the superior mesenteric root following the embryological planes between the visceral and the parietal fascias; 2) mobilization of the mesocolon from the duodenum and the pancreas and identification of vascular structures, especially the veins around the pancreas; and 3) central vascular ligation of the colonic vessels at their origin, taking into account the vascular variations within the mesocolonic vessels and the autonomic nerves around the superior mesenteric artery. LIMITATIONS: The limitation of this study was the number of the cadavers used. CONCLUSIONS: Successful complete mesocolic excision with central vascular ligation depends on an accurate knowledge of the surgical anatomical planes and the vascular anatomy of the colon.

Anatomical basis of laparoscopic medial-to-lateral mobilization of the descending colon.

In laparoscopic colorectal resection, the medial-to-lateral approach has been largely adopted. This approach can be initiated by the division of either the inferior mesenteric artery (IMA) or the inferior mesenteric vein (IMV). This cadaveric study aimed to establish the feasibility of IMV dissection as the initial landmark of medial-to-lateral left colonic mobilization for evaluating the size of the peritoneal window between the IMV at the lower part of the pancreas and the origin of the IMA (IMA-IMV distance) and the point of origin of the IMA compared to the lower edge of the third part of the duodenum (IMA-D3 distance). These distances were recorded on 30 fresh cadavers. The IMA-D3 distance was 0.4 ± 2.2 cm (mean ± SD). The IMA originated from the aorta at the level of or below the D3 in 21 cases (70%). The IMA-IMV distance was 5.5 ± 1.8 cm and was greater or equal to 5 cm (large window) in 21 cases (70%). IMA-IMV distance was correlated with IMA-D3 showing that a large window was inversely correlated with a low IMA origin (P < 0.001). IMA-D3 distance was not correlated with weight, height and sex. IMA-IMV distance was largerin male (6.7 ± 0.9 vs. 4.9 ± 1.8, P = 0.001) and correlated with weight, (r = 0.60, 95%CI = 0.03-0.10, P < 0.001) and height (r = 0.54, 95%CI = 0.05-0.21, P = 0.002). IMV can be used as the initial landmark for laparoscopic medial-to-lateral dissection in two-thirds of cases. A too-small window can require first IMA division. The choice between the two different medial-to-lateral approaches could be made by evaluating the anatomical relationship between IMA, IMV, and D3.

Self-stabilizing colonic capsule endoscopy: pilot study of acute canine models.

Video capsule endoscopy (VCE) is a noninvasive method for examining the gastrointestinal tract which has been successful in small intestine studies. Recently, VCE has been attempted in the colon. However, the capsule often tumbles in the wider colonic lumen, resulting in missed regions. Self-stabilizing VCE is a novel method to visualize the colon without tumbling. The aim of the present study was to comparatively quantify the effect of stabilization of a commercially available nonmodified capsule endoscope (CE) MiroCam and its modified self-stabilizing version in acute canine experiments. Two customized MiroCam CEs were reduced in volume at the nonimaging back-end to allow the attachment of a self-expanding, biocompatible stabilizing device. Four mongrel dogs underwent laparotomy and exteriorization of a 15-cm segment of the proximal descending colon. A single CE, either self-stabilizing or nonmodified was inserted through an incision into the lumen of the colon followed by pharmacologically induced colonic peristalsis. The inserted capsule was propelled distally through the colon and expelled naturally through the anus. Novel signal processing method was developed to quantify the video stabilization based on camera tracking a predetermined target point (locale). The average locale trajectory, the average radius movement of the locale, and the maximum rate of change of the locale for sequential images were significantly lower for the stabilized capsules compared to the nonstabilized ones . The feasibility of self-stabilized capsule endoscopy has been demonstrated in acute canine experiments.

Anatomical variations in the level of origin of the sigmoid colon from the descending colon and the attachment of the sigmoid mesocolon.

The origin of the sigmoid colon is considered constant as is the V-shaped attachment of the sigmoid mesocolon attachment. This study was undertaken to establish anatomical variations in the level of origin of the sigmoid colon (590 autopsies; 403 Africans, 91 Indians, and 96 Whites), and the shape of the attachment of the sigmoid mesocolon (211 autopsies, 127 Africans, 47 Indians, and 37 Whites) in different population groups. The low-level origin was significantly less common among Africans compared with the other population groups (P = 0.003) and the high-level origin was significantly more common in Africans (P = 0.003). A midlevel origin was similar in all three groups. The shape of the mesocolon attachment was either straight (94), inverted U-shaped (79), or inverted V-shaped (38). The straight shape was more common in Whites (Whites vs. African and Indian P = 0.003), and the U-shape more common in Africans (African vs. Whites P = 0.042). The distribution of the V-shape was similar. There are anatomical variations in the level of origin of the sigmoid colon from the descending colon as well as in the shape of the attachment of its mesocolon. These variations are population based.

Colosigmoid junction: morphohistologic, morphometric, and endoscopic study with identification of colosigmoid canal with sphincter.

To study the anatomical structure of the colosigmoid junction, 15 cadaveric specimens were studied morphologically, another 15 histologically, and a morphometric study was done in 10 specimens. Specimens consisted of the descending colon, sigmoid colon, and the colosigmoid junction. Histologic specimens were stained with hematoxylin and eosin and Masson's trichrome stain. Morphometric studies used an image analysis system. The colosigmoid junction was investigated endoscopically in 18 healthy volunteers. A narrow segment having a mean length of 5.2 +/- 1.1 cm was identified both externally and internally between the descending and sigmoid colon. We called this segment the colosigmoid canal. Mucosal folds were found crowded in the colosigmoid canal, the lower end of which formed a nipple and was surrounded by a fornix. Histologically, the colosigmoid canal mucosa showed multiple folds. Its circular muscle was thicker than that of the descending or the sigmoid colon and confirmed morphometrically. The longitudinal muscle was thicker in only 4 of 10 specimens. Both the narrowing and the mucosal crowding were verified endoscopically. The colosigmoid junction is the narrow segment between the descending and the sigmoid colon. Histologic, morphometric and endoscopic studies indicated the presence of a sphincter in the colosigmoid canal. A colosigmoid sphincter is suggested to control the passage of colonic contents from the descending colon to the colosigmoid canal as well as to prevent reflux of sigmoid contents into the descending colon.

Sympathovagal balance fluctuates during colonoscopy.

BACKGROUND AND STUDY AIM: Colonoscopy is a common gastroenterological procedure for investigation of the bowel. The main side effects of colonoscopy are pain during investigation, cardiovascular complications and very rarely even death. The aim of this study was to compare the continuous fluctuation of heart rate variability (HRV) components during colonoscopy under normal conditions, analgesia/sedation, and total intravenous anesthesia. PATIENTS AND METHODS: 37 consecutive patients (aged 35 - 65), were randomly allocated to three groups: no sedation (control group 1); analgesia/sedation (group 2); and total intravenous anesthesia (group 3). Holter electrocardiography and subsequent frequency domain analysis were undertaken. The low-frequency (LF, 0.04 - 0.15 Hz) and the high-frequency (HF, 0.15 - 0.40 Hz) components were estimated using spectral analysis in the usual way. Normalized units (nu) were calculated from the following equations: LFnu = LF/(LF + HF), and HFnu = HF/(LF + HF). RESULTS: Groups 2 and 3 were found to have a significantly lower HFnu and higher LFnu than group 1 essentially throughout the procedure. A one-way analysis of variance and t-test confirmed that the differences were significant when the colonoscope reached the splenic flexure as were the LF/HF balances at the splenic and hepatic flexures and the cecum. The percentage change in LF/HF was also analyzed, and it was found that in group 3 the mean change was over 136 % when the colonoscope reached the sigmoid flexure, which was significantly higher than in the other two groups. CONCLUSION: Most changes in HRV components occurred during colonoscopy of the left side of the bowel. Analgesia/sedation and total intravenous anesthesia increased HRV by increasing the LF component.