scholarly journals Mathematical Modelling of the Structure and Function of the Lymphatic System

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1467
Author(s):  
Anastasia Mozokhina ◽  
Rostislav Savinkov

This paper presents current knowledge about the structure and function of the lymphatic system. Mathematical models of lymph flow in the single lymphangion, the series of lymphangions, the lymph nodes, and the whole lymphatic system are considered. The main results and further perspectives are discussed.

Author(s):  
А.А. Коваленко ◽  
Г.П. Титова ◽  
В.К. Хугаева

Оперативное лечение различных заболеваний кишечника сопровождается осложнениями в виде нарушений микроциркуляции в области анастомоза кишки. Ранее нами показана способность лимфостимуляторов пептидной природы восстанавливать нарушенную микроциркуляцию, что послужило основой для настоящего исследования. Цель работы - оценка влияния стимуляции лимфотока в стенке кишки на процессы восстановления микроциркуляции, структуры и функции тонкой кишки в области оперативного вмешательства. Методика. В экспериментах на наркотизированных крысах (хлоралгидрат в дозе 0,6 г/кг в 0,9% растворе NaCl) моделировали различные поражения тонкой кишки (наложение лигатуры, перевязка 1-3 брыжеечных артерий, перекрут петли кишки вокруг оси брыжейки, сочетание нескольких видов повреждений). Резекция поврежденного участка через 1 сут. с последующим созданием тонкокишечного анастомоза завершалась орошением операционного поля раствором пептида-стимулятора лимфотока (40 мкг/кг массы животного в 1 мл 0,9% раствора NaCl). На 7-е сут. после операции проводили гистологическое исследование фрагмента кишки в области анастомоза. Результаты. На 7-е сут. после резекции у выживших животных (летальность вследствие кишечной непроходимости составляла 30%) имеют место морфологические признаки острых сосудистых нарушений стенки кишки, изменений кровеносных и лимфатических микрососудов, интерстициальный отек всех слоев стенки кишки, дилатация просвета кишки, повреждение всасывающего эпителия ворсин с истончением щеточной каемки клеток, морфологические признаки гиперфункции бокаловидных клеток. Использование лимфостимулятора пептидной природы после операции увеличивало выживаемость животных на 24%. У части животных отмечалось уменьшение расширения просвета кишки, у других практически полная его нормализация. Восстанавливалась форма кишечных ворсин и распределение бокаловидных клеток. Отсутствовали признаки внутриклеточного и межмышечного отека. Отмечено умеренное полнокровие венул. Заключение. Использование лимфостимулятора при хирургическом лечении кишечной непроходимости увеличивает выживаемость животных на 24% по сравнению с контролем, способствует более раннему восстановлению структуры и функции тонкой кишки. Полученные результаты свидетельствуют о перспективности использования стимуляции лимфотока при операциях на кишечнике. Surgical treatment of bowel diseases is associated with complications that cause microcirculatory disturbances in the anastomosis area and may lead to a fatal outcome. This study was based on our previous finding that peptide-type lymphatic stimulators are able to restore impaired microcirculation. The aim of this work was stimulating the lymph flow in the intestinal wall to facilitate recovery of microcirculation, structure and function of the small intestine in the area of surgical intervention. Methods. In experiments on anesthetized rats (0.6 g/kg chloral hydrate in 0.9% NaCl), various small bowel lesions were modeled (bowel ligation, ligation of 1-3 mesenteric arteries, gut torsion, combination of several lesion types). In 24 h, the damaged area was resected, and a small intestine anastomosis was creased. The surgery was completed with irrigation of the operative field with a solution of lymph flow stimulating peptide (40 мg/kg body weight in 1 ml of 0.9% NaCl). A gut fragment from the anastomosis area was examined histologically on day 7 after the surgery. Results. On the 7th day after removing the intestinal obstruction, the surviving animals (lethality 30%) had morphological signs of acute vascular disorders in the intestinal wall; changes in blood and lymphatic microvessels; interstitial edema of all intestinal wall layers; dilatation of the intestinal lumen; damage to the absorptive epithelium of villi with thinning of the brush border, and hyperfunction of mucous (goblet) cells. The use of the peptide after surgery increased the survival rate of animals by 24% and provided a smaller dilatation of the intestinal lumen in some animals. In other animals, the lumen recovered. The shape of intestinal villi and distribution of goblet cells were restored. Signs of intracellular and intermuscular edema were absent. Moderate venular congestion was noticed. Conclusion. Using the lymphatic stimulator in surgical treatment of intestinal obstruction increases the survival rate of animals by 24% compared to the control, facilitates earlier restoration of the small intestine structure and function. The obtained results indicated the effectiveness of lymphatic stimulation in intestinal surgery.


1999 ◽  
Vol 79 (1) ◽  
pp. S23-S45 ◽  
Author(s):  
DAVID N. SHEPPARD ◽  
MICHAEL J. WELSH

Sheppard, David N., and Michael J. Welsh. Structure and Function of the CFTR Chloride Channel. Physiol. Rev. 79 , Suppl.: S23–S45, 1999. — The cystic fibrosis transmembrane conductance regulator (CFTR) is a unique member of the ABC transporter family that forms a novel Cl− channel. It is located predominantly in the apical membrane of epithelia where it mediates transepithelial salt and liquid movement. Dysfunction of CFTR causes the genetic disease cystic fibrosis. The CFTR is composed of five domains: two membrane-spanning domains (MSDs), two nucleotide-binding domains (NBDs), and a regulatory (R) domain. Here we review the structure and function of this unique channel, with a focus on how the various domains contribute to channel function. The MSDs form the channel pore, phosphorylation of the R domain determines channel activity, and ATP hydrolysis by the NBDs controls channel gating. Current knowledge of CFTR structure and function may help us understand better its mechanism of action, its role in electrolyte transport, its dysfunction in cystic fibrosis, and its relationship to other ABC transporters.


2019 ◽  
Vol 20 (6) ◽  
pp. 1353 ◽  
Author(s):  
Quan Wang ◽  
Sha Yang ◽  
Shubo Wan ◽  
Xinguo Li

As a secondary messenger, calcium participates in various physiological and biochemical reactions in plants. Photosynthesis is the most extensive biosynthesis process on Earth. To date, researchers have found that some chloroplast proteins have Ca2+-binding sites, and the structure and function of some of these proteins have been discussed in detail. Although the roles of Ca2+ signal transduction related to photosynthesis have been discussed, the relationship between calcium and photosynthesis is seldom systematically summarized. In this review, we provide an overview of current knowledge of calcium’s role in photosynthesis.


1983 ◽  
Vol 61 (8) ◽  
pp. 942-948 ◽  
Author(s):  
Paul G. Scott

Macromolecules which appear to be integral constituents of basement membranes include type IV collagen, the glycoprotein laminin, and heparan sulphate proteoglycan. Another glycoprotein, fibronectin, may occupy an intermediate position between some lining cells and their basement membranes but is not, however, restricted to this location. An additional form of collagen, genetic type V which differs significantly from type IV collagen in structure, appears to be associated with some basement membranes, possibly linking them to underlying connective tissue. The main structural features of each of these macromolecules, as presently understood, are reviewed here as a background to the experimental papers in this "mini-symposium."


2008 ◽  
Vol 71 (2) ◽  
pp. 69-76 ◽  
Author(s):  
Osamu Ohtani ◽  
Yuko Ohtani

Cancers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 857 ◽  
Author(s):  
Cora Roehlecke ◽  
Mirko H. H. Schmidt

Intercellular communication among cancer cells and their microenvironment is crucial to disease progression. The mechanisms by which communication occurs between distant cells in a tumor matrix remain poorly understood. In the last two decades, experimental evidence from different groups proved the existence of thin membranous tubes that interconnect cells, named tunneling nanotubes, tumor microtubes, cytonemes or membrane bridges. These highly dynamic membrane protrusions are conduits for direct cell-to-cell communication, particularly for intercellular signaling and transport of cellular cargo over long distances. Tunneling nanotubes and tumor microtubes may play an important role in the pathogenesis of cancer. They may contribute to the resistance of tumor cells against treatments such as surgery, radio- and chemotherapy. In this review, we present the current knowledge about the structure and function of tunneling nanotubes and tumor microtubes in cancer and discuss the therapeutic potential of membrane tubes in cancer treatment.


Author(s):  
C. Weissmann ◽  
M. A. Billeter ◽  
H. Weber ◽  
H. M. Goodman ◽  
J. Hindley

2002 ◽  
Vol 80 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Jeremy H Brock

This paper reviews our current knowledge of the structure and function of the iron-binding protein lactoferrin. In particular, it attempts to relate the various proposed physiological functions of lactoferrin to its most characteristic biochemical properties, i.e. its ability to bind iron and its highly basic nature. The extent to which various physiological functions can be considered as definitely established is critically reviewed, and suggestions for future research are proposed.Key words: lactoferrin, iron, nutrition, immunology, infection, inflammation.


2019 ◽  
Vol 34 (5) ◽  
pp. 261-268 ◽  
Author(s):  
Anastasia S. Mozokhina ◽  
Sergey I. Mukhin ◽  
Gennady I. Lobov

Abstract A model of lymph flow in the human lymphatic system in the quasi-one-dimensional approach has been created and investigated under different conditions. The model includes an implementation of contractions and valve influence on lymph flow. We consider contractions of lymphatic vessels and their influence on resulting flow in the whole network of lymphatic vessels and lymph nodes. We have investigated flow with zero pressure gradient and have found parameters, which influence the efficiency of contractions most significantly.


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