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Paper 3
Published in Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw, The Final FRCR, 2020
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw
Ultrasound and fluoroscopy can be helpful in assessing for midgut volvulus. Ultrasound findings include the ‘whirlpool’ sign caused by a twisting of the mesenteric vessels. The superior mesenteric vein usually lies to the right of the superior mesenteric artery; in malrotation it lies to the left. The retro-mesenteric D3 part of the duodenum may not be visible between the aorta and superior mesenteric vessels.
Endocrine and Neuroendocrine Tumors
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
Natasha Shrikrishnapalasuriyar, P.N. Plowman, Márta Korbonits, Ashley B. Grossman
Midgut carcinoid tumors are small intestinal NETs derived from serotonin-producing enterochromaffin cells, and have an incidence of approximately 0.67–0.81 per 100,000/year. NETs arising from the midgut may present incidentally, or with bowel obstruction. Tumor growth may be slow and without clinical features until it metastasizes to the liver, in which case secretory products may leak into the circulation and cause a carcinoid syndrome in one-third of cases. The principal product, 5HT or serotonin, is associated with watery diarrhea and flushing, and occasionally bronchospasm, although other neuroactive agents may be involved. The 5HT is also pro-fibrotic and may cause a desmoplastic response in the gut, or valvular cardiac defects—carcinoid heart disease. In such cases the valvular abnormalities are usually right-sided tricuspid and pulmonary incompetence, although if there is a patent foramen ovale there may occasionally be left-sided defects. The carcinoid syndrome is essentially diagnosed on the basis of 24-hour urinary 5HIAA excretion, although many foods can also elevate 5HIAA, and newer plasma assays are becoming available.
Aedes Mosquitoes: The Universal Vector
Published in Jagriti Narang, Manika Khanuja, Small Bite, Big Threat, 2020
Annette Angel, Bennet Angel, Neelam Yadav, Jagriti Narang, Surender Singh Yadav, Vinod Joshi
After mating when the females have the urge to suck blood, they sense the host by body odor and CO2 dispersed by a host closest to its vicinity. Studies have shown that in 99% of the cases, Aedes aegypti prefer human blood, while in less than 1% cases, they may feed on other vertebrate hosts, mainly bovine, swine, cat, rat, and chicken (Ponlawat and Harrington, 2005). Some studies also hypothesize the role of ADP and ATP identification by mosquitoes in identifying their preferred host (Clements, 2000). During the ingestion of blood meal, a mosquito also injects its saliva into the host. It is during this time when any virus present inside a mosquito system is released into the host’s blood. On the other hand, if the mosquito is drawing a blood meal from a human host infected with any viral disease, the virus reaches the mosquito’s midgut along with the blood. In the midgut, the blood components get digested. On the other hand, if the mosquito is infected, the saliva that enters the human blood from the salivary glands carries the virus and infects the host.
Spatiotemporal organization of enteroendocrine peptide expression in Drosophila
Published in Journal of Neurogenetics, 2021
Sooin Jang, Ji Chen, Jaekyun Choi, Seung Yeon Lim, Hyejin Song, Hyungjun Choi, Hyung Wook Kwon, Min Sung Choi, Jae Young Kwon
The adult Drosophila digestive tract can be divided into three regions based on morphology, function, and developmental origin: the foregut, midgut, and hindgut (Guo, Lucchetta, Rafel, & Ohlstein, 2016; Zeng, Chauhan, & Hou, 2013). The adult midgut can be largely divided into the anterior, middle, and posterior midgut, and has been subdivided further into several distinct sub-regions based on morphological, molecular, physiological, and genetic differences (Buchon & Osman, 2015; Buchon et al., 2013; Marianes & Spradling, 2013; Miguel-Aliaga, Jasper, & Lemaitre, 2018). The enteroendocrine cells are only present in the midgut (Veenstra, Agricola, & Sellami, 2008). The fly midgut has been an extremely useful model system to not only study the functions but also the differentiation of enteroendocrine cells, following the discovery of intestinal stem cells (ISCs) in the Drosophila midgut (Micchelli & Perrimon, 2006; Ohlstein & Spradling, 2006).
Does transverse colon cancer spread to the extramesocolic lymph node stations?
Published in Acta Chirurgica Belgica, 2021
Bulent C. Yuksel, Sadettin ER, Erdinç Çetinkaya, Ahmet Keşşaf Aşlar
Although CME and CVL can be applied to all colon cancers, these procedures are slightly different in transverse colon cancers. The transverse colon shows embryological and anatomical oddities due to its midgut and hindgut origin and the location between the foregut and midgut-hindgut. The proximal 2/3 part is the end of the midgut while the distal part is the beginning of the hindgut. The proximal portion of the superior mesenteric artery and the foregut components, such as the great omentum, pancreas and lesser sac, are intertwined. This convoluted relationship suggests the possibility of an interaction between embryological areas. This relationship is even more evident in the venous drainage of the omentum and pancreas. These connections between embryological planes were described by Stelzner et al. in cadaveric studies [12]. In their prospective analysis, Perrakis et al. demonstrated tumor manifestation extending beyond this embryological area [13].
Difference between right-sided and left-sided colorectal cancers: from embryology to molecular subtype
Published in Expert Review of Anticancer Therapy, 2018
Seung Yoon Yang, Min Soo Cho, Nam Kyu Kim
The endodermal gut tube created by body folding during the fourth week of gestation consists of a blind-ended cranial foregut, a blind-ended caudal hindgut, and a midgut open to the yolk sac through the vitelline duct [11]. The midgut forms the distal duodenum, jejunum, ileum, cecum, ascending colon, and proximal two-thirds of the transverse colon. The hindgut forms the distal third of the transverse colon, the descending and sigmoid colon, and the upper two-thirds of the anorectal canal. Just superior to the cloacal membrane, the primitive gut tube forms an expansion called the cloaca. During the fourth to sixth weeks, a coronal urorectal septum partitions the cloaca into the urogenital sinus, which will give rise to urogenital structures, and a dorsal anorectal canal [12]. As the right and left sides of the colon derive from different embryologic origins, anatomically, the proximal colon receives its main blood supply from the superior mesenteric artery with its capillary network being multilayered. The distal colon is perfused by the inferior mesentery artery. Between these two main sources, there is a watershed area located just proximal to the splenic flexure where branches of the left branch of the middle colic artery anastomose with those of the left colic artery. This area represents the border of the embryologic midgut and hindgut. Venous drainage of the colon largely follows the arterial supply with superior and inferior mesenteric veins draining both the right and left halves of the colon.