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Internal Fistulas in the Rat
Published in Waldemar L. Olszewski, CRC Handbook of Microsurgery, 2019
The animal receives 1 mℓ of Intra-lipid® (Vitrum, Stockholm) orally by means of a gastric tube 1 hr before the operation. After opening the abdomen by a midline incision a right nephrectomy is carried out. Using microsurgical instruments, the cannulation sites are carefully dissected under a Zeiss® OP-MI 6 operation microscope with a magnification of approximately 4 ×. Silastic® tubing (Dow Corning, internal diameter 0.30 mm, external diameter 0.64 mm) filled with heparin in saline (50 U/mℓ) is inserted first into the ureter and fixed with 8/0 nylon. The ureter is flushed with heparin/saline solution via the cannula until the bladder is filled. This is to prevent clotting in the early stage of the cannulation procedure. In the ensuing period a regular flow prevents clotting of the chyli. The mesenteric lymph duct is tied close to its outflow point into the thoracic duct with 8/0 nylon. Because the mesenteric lymph duct is very intimately connected to the mesenteric artery it is of great help to use atraumatic suture material (8/0 nylon connected to a BV 2 needle, Ethicon, Germany). Using this, it is not necessary to separate both structures; with a small needle it is rather easy to slip through the layer of connective tissue between the duct and the artery. A cut is made distally from this ligature. The cannula is inserted and fixed with the same suture material. Uniformly, immediately after cannulation, the milky fluid is seen entering the cannula. The intestines are brought back into the abdomen and the wound is closed. To help recover from anesthesia the animals are put for some time under an IR lamp.
Gastrointestinal Lymphatics
Published in Waldemar L. Olszewski, Lymph Stasis: Pathophysiology, Diagnosis and Treatment, 2019
Although lymph stasis is not strictly a cause of ascites in cirrhosis, there is evidence that lymphatic insufficiency plays a contributory role in the persistence of ascites in cirrhosis. The “lymph imbalance” theory of ascites enunciated by Witte et al.135 postulates that a discrepancy arises between the rate of fluid input into the peritoneal cavity and the rate of return of fluid to blood via lymphatics. In early cirrhosis with rising portal venous pressure, the lymphatics of the gut and thoracic duct transport progressively more interstitial fluid, and any peritoneal fluid which forms is taken up by diaphragmatic lymphatics. These latter vessels drain to the right lymph duct in the thorax. This vessel has a limited transport capacity, and an imbalance between input and drainage arises. Aggravating factors in this situation include incompetence of valves in distended mesenteric lymphatics, scarring with obliteration of lymphatic vessels in the diaphragm, and resistance to lymph flow across the lymphaticovenous confluence in the neck. Some support for this theory comes from the amelioration of the condition by surgical refashioning of the thoracic duct-venous junction in the neck or by creation of a “megalymphatic” channel, i.e., a peritoneovenous shunt which not only clears the ascites but results in normalization of the deranged salt and water homeostatic mechanisms characteristics of cirrhotic ascites. Further support comes from estimates of lymphatic conductance (flow rate per unit pressure difference) in patients with cirrhosis who do or do not have ascites.136
Interstitium and Lymphatics
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
The main sites where lymph is returned to the blood are the unions of the thoracic duct, and of the right lymph duct, with the great veins in the neck. However, there are many other places where such communications exist. It is not certain to what extent they are normally patent, although it is well known that much more lymph is formed in the periphery than ever reaches the main lymph ducts.33 Such additional communications open when the intralymphatic pressures rise high enough — and thus help to prevent lymphedema.
Enhanced dissolution and bioavailability of revaprazan using self-nanoemulsifying drug delivery system
Published in Pharmaceutical Development and Technology, 2022
Yoon Tae Goo, Cheol-Ki Sa, Min Song Kim, Gi Hyeong Sin, Chang Hyun Kim, Hyeon Kyun Kim, Myung Joo Kang, Sangkil Lee, Young Wook Choi
Oral administration is a preferable route for drug delivery because of its convenience and safety. Orally administrated drugs are dissolved in the gastrointestinal (GI) fluid, transported into epithelial cells, and eventually passed into the bloodstream for systemic circulation. Following uptake by epithelial cells, only a small portion of the absorbed drugs can bind to lipoproteins and enter the lacteal ducts (Liao et al. 2019). Substances absorbed by the lacteal ducts enter the mesenteric lymph duct, pass through the cisterna chyli, and flow upward into the thoracic duct (Hsu and Itkin 2016). Thereafter, lymphatic fluid flows into the bloodstream at the junction of the subclavian vein and the internal jugular vein (Hsu and Itkin 2016). Unlike absorption through intestinal capillaries, lymphatic transport is not connected to the portal vein. Therefore, lymphatic transport improves oral bioavailability (BA) by evading the first-pass effect, thereby enhancing the total systemic BA (Caliph et al. 2000; Sanjula et al. 2009).
Mechanisms of oral absorption improvement for insoluble drugs by the combination of phospholipid complex and SNEDDS
Published in Drug Delivery, 2019
Yingpeng Tong, Qin Zhang, Wen Shi, Jianxin Wang
The intestinal lymphatic transport studies were conducted according to the established methods with some modifications (Chaudhary et al., 2015; Li et al., 2017). SD rats (male, 280–320 g) were fasted for 12 h with free access to water. 30 min before the experiment, each rat was fed with 1 mL of sesame oil to facilitate viewing of the mesenteric lymph duct due to its milky-white in appearance and adhesion to the mesenteric artery. At the beginning of the experiments, the rats were anesthetized by intraperitoneal injection of 200 mg kg−1 sodium pentobarbital, then shaved and disinfected on the right side of their necks and flanks. The jugular vein in the right neck was isolated and used to collect blood sample by cannulating with PE10 tubing. Then, the mesenteric lymph duct and duodenum in the right abdomen were exposed and cannulated with PE10 and PE50 tubing, respectively. The mesenteric lymph duct was fixed with instant cyanoacrylate adhesive. The PE50 tube inserted into the duodenum was adopted for administration and saline infusion. The body temperature of the rats was maintained by a heating pad set at 37 °C.
A conservative approach to a thoracic duct injury caused by left subclavian vein catheterization
Published in Egyptian Journal of Anaesthesia, 2018
Vedran Premuzic, Ranko Smiljanic, Drazen Perkov
Thoracic duct, wide only 2–6 mm, transports lymph from the lower part of the body and mixing with fluids from intestines form a mixture called chyle and pours into venous circulation by sometimes multiple branches. Its variations are seen in more than one third of the population. Cisterna chyli is present in only 50% of humans, when absent, there are 2 or more lymph ducts. Clouse relationship with other structures leads of injury during operations, a main cause of traumatic duct injury. Other causes as malignancies and coronary artery bypass are not so common, especially injuries during catheter insertions (<1% of cases). Periprocedural central venous catheter complications are mostly related to pneumo or hematothorax, vascular injury and the catheter tip malposition and very rarely thoracic duct injury which is similar with our experiences. The rate of these complications is higher in patients with prior temporary or permanent central venous catheters on hemodialysis. Patients with chylothorax manifest with onsets of pleuritic pain or dyspnea caused by pleural effusions which can also be absent in cases with low flow chylothorax and manifest only as unspecific pleural effusions on chest X-rays [7].