Limitations to Fluid Replacement During Exercise

1999 ◽  
Vol 24 (2) ◽  
pp. 173-187 ◽  
Author(s):  
Ron J. Maughan ◽  
John B. Leiper

Fluid replacement during exercise is essential for endurance exercise performance and reducing the risk of heat illness. Fluids supply water, which ameliorates dehydration, and also substrate for the working muscles. Absorption of water and nutrients occurs in the upper part of the small intestine, and replacement may be limited by the rate at which fluid is emptied from the stomach or absorbed in the intestine. Gastric emptying of liquids is influenced primarily by the volume of fluid in the stomach and by its energy density. Increasing the volume will speed emptying, but increasing the nutrient content will slow emptying. Osmolality, temperature, and pH of drinks, as well as exercise intensity, are of minor importance. Intestinal water absorption is a passive process: water follows osmotic gradients but will also follow the active absorption of nutrients, especially glucose, which is actively co-transported with sodium. Water transport is maximised by the presence in the intestine of hypotonic solutions of glucose and sodium. Hypertonic solutions promote net water secretion into the intestinal lumen, resulting in a temporary net loss of water from the body. The amount of fluid ingested by athletes is normally much less than can be tolerated, therefore issues such as palatability and practising drinking during training are important. Key words: dehydration, rehydration, gastric emptying, intestinal absorption

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Ronald J. Jandacek ◽  
Stephen J. Genuis

Many individuals maintain a persistent body burden of organochlorine compounds (OCs) as well as other lipophilic compounds, largely as a result of airborne and dietary exposures. Ingested OCs are typically absorbed from the small intestine along with dietary lipids. Once in the body, stored OCs can mobilize from adipose tissue storage sites and, along with circulating OCs, are delivered into the small intestine via hepatic processing and biliary transport. Retained OCs are also transported into both the large and small intestinal lumen via non-biliary mechanisms involving both secretion and desquamation from enterocytes. OCs and some other toxicants can be reabsorbed from the intestine, however, they take part in enterohepatic circulation(EHC). While dietary fat facilitates the absorption of OCs from the small intestine, it has little effect on OCs within the large intestine. Non-absorbable dietary fats and fat absorption inhibitors, however, can reduce the re-absorption of OCs and other lipophiles involved in EHC and may enhance the secretion of these compounds into the large intestine—thereby hastening their elimination. Clinical studies are currently underway to determine the efficacy of using non-absorbable fats and inhibitors of fat absorption in facilitating the elimination of persistent body burdens of OCs and other lipophilic human contaminants.


1973 ◽  
Vol 12 (2) ◽  
pp. 585-601
Author(s):  
J. FORSTNER ◽  
N. TAICHMAN ◽  
V. KALNINS ◽  
G. FORSTNER

A high-molecular-weight glycoprotein (HMG), representing the majority of the soluble glycoprotein hexosamine and hexose in the intestine, was isolated by Sepharose 4B chromatography from high-speed supernatants of rat small intestinal homogenate. Fluorescein-labelled globulin, from rabbit antiserum produced against HMG, specifically stained supra-nuclear mucus vesicles of goblet cells in small intestine and colon as well as gastric pit cells in the body of the stomach and mucus-producing cells in the sublingual salivary gland. A single precipitin line was found when HMG was tested against its antibody by agar immunodiffusion and immunoelectrophoresis. No cross-reactivity was observed between antibody and rat serum or extracts from microvillus membrane, human colon and pig intestine. Precipitin lines which fused with the HMG precipitin arc in apparent identity were observed with antigens in intestinal lumen washings, and in small-molecular-weight fractions from intestinal cell sap. When studied by cellulose acetate electrophoresis, cetyl trimethylammonium bromide precipitation and precursor labelling with [I-14C]glucosamine, HMG behaved as a single homogeneous glycoprotein free of detectable protein contamination. These results imply that HMG is a major component of goblet-cell mucus in the small intestine, and suggest that it is similar to mucin produced throughout the gastrointestinal tract. HMG is the first glycoprotein, isolated without the aid of proteolytic agents, which has been specifically identified as a product of the goblet cell.


2012 ◽  
Vol 40 (2) ◽  
pp. 99-107 ◽  
Author(s):  
Helen Prior ◽  
Lorna Ewart ◽  
Jonathan Bright ◽  
Jean-Pierre Valentin

The aim of this investigation was to determine whether a shorter fasting period than the one historically employed for the charcoal meal test, could be used when measuring gastric emptying and intestinal transit within the same animal, and to ascertain whether the scientific outcome would be affected by this benefit to animal welfare. Rats and mice were fasted for 0, 3, 6 or 18 hours before the oral administration of vehicle or atropine. One hour later, the animals were orally administered a charcoal meal, then 20 minutes later, they were killed and the stomach and small intestine were removed. Intestinal transit time (the position of the charcoal front as a percentage of the total length of the small intestine) and relative gastric emptying (weight of stomach contents) were measured. Rats and mice fasted for six hours showed results for gastric emptying and intestinal transit which were similar to those obtained in animals fasted for 18 hours. Reducing the fasting period reduced the body weight loss in both species, and mice on shorter fasts could be group-housed, as hunger-induced fighting was lessened. Therefore, a fasting period of six hours was subsequently adopted for charcoal meal studies at our institution.


2008 ◽  
Vol 294 (5) ◽  
pp. G1171-G1180 ◽  
Author(s):  
Heleen M. de Vogel-van den Bosch ◽  
Nicole J. W. de Wit ◽  
Guido J. E. J. Hooiveld ◽  
Hanneke Vermeulen ◽  
Jelske N. van der Veen ◽  
...  

Transporters present in the epithelium of the small intestine determine the efficiency by which dietary and biliary cholesterol are taken up into the body and thus control whole-body cholesterol balance. Niemann-Pick C1 Like Protein 1 (Npc1l1) transports cholesterol into the enterocyte, whereas ATP-binding cassette transporters Abca1 and Abcg5/Abcg8 are presumed to be involved in cholesterol efflux from the enterocyte toward plasma HDL and back into the intestinal lumen, respectively. Abca1, Abcg5, and Abcg8 are well-established liver X receptor (LXR) target genes. We examined the effects of a high-fat diet on expression and function of cholesterol transporters in the small intestine in mice. Npc1l1, Abca1, Abcg5, and Abcg8 were all downregulated after 2, 4, and 8 wk on a cholesterol-free, high-fat diet. The high-fat diet did not affect biliary cholesterol secretion but diminished fractional cholesterol absorption from 61 to 42% ( P < 0.05). In an acute experiment in which triacylglycerols of unsaturated fatty acids were given by gavage, we found that this downregulation occurs within a 6-h time frame. Studies in LXRα-null mice, confirmed by in vitro data, showed that fatty acid-induced downregulation of cholesterol transporters is LXRα independent and associated with a posttranslational increase in 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity that reflects induction of cholesterol biosynthesis as well as with a doubling of neutral fecal sterol loss. This study highlights the induction of adaptive changes in small intestinal cholesterol metabolism during exposure to dietary fat.


2020 ◽  
Vol 26 (2) ◽  
pp. 45-50
Author(s):  
V.V. Bobyr ◽  
L.O. Stechenko ◽  
V.P. Shirobokov ◽  
O.A. Nazarchuk ◽  
O.V. Rymsha

The past decade is characterized by a noticeable increase in the interest of physicians in all areas of activity in the development of new and improvement of existing approaches to the correction of dysbiotic disorders. Among them, the concept of using probiotics occupies a leading position. At the same time, some enterosorbents, the mechanism of action of which is largely due to the sanitation of the intestinal lumen and due to this improvement of conditions for the vital activity of the physiological microbiota, can be attributed to the group of means of improving the normal microflora. In the context of an increase in the level of resistance to antibacterial agents, the inclusion of enterosorbents in the complex therapy of dysbiosis is an important and pathogenetically justified approach. The aim of the work was to clarify the effectiveness of the use of sorbents and probiotics for the prevention of structural and morphological disorders in the small intestine of white mice developing against the background of antibiotic-induced dysbiosis. Electron-microscopic methods showed that in the mucous membrane of the small intestine of mice after using the probiotic “Simbiter” the extinction of manifestations of cytodestructive disorders is observed. In addition, the obtained electron microscopic data, indicating the ability of probiotic drugs with the simultaneous introduction into the body of animals with a complex of antibiotics, to stimulate the body’s immune response. As a result of ultrastructural analysis of the mucous membrane of the small intestine of mice, the formation of dysbiosis in which occurred against the background of the use of enterosorbents, a decrease in the severity of structural damage was found, compared with the group of animals that received only antibiotics. After using “Symbiogel”, activation of plasma cells was registered, which can be an indicator of the inflammatory process and the activity of the immune response in general, as evidenced by the detection of plasma cells with dilated tubules. In general, it should be noted that the use of “Symbiogel” for the prevention of dysbiotic disorders contributes to the formation of a more pronounced immune response, compared with probiotic drugs. So, on the model of antibiotic-induced dysbiosis at the ultrastructural level, the ability of multiprobiotics “Simbiter®” and sorbent “Symbiogel” to reduce cytodestructive changes in the mucous membrane of the small intestine of mice and normalize morphoimunogenesis was proved.


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.


Author(s):  
Kinesh V P ◽  
Neelam D P ◽  
Punit B ◽  
Bhavesh S.B ◽  
Pragna K. S

Diabetes mellitus is a serious pathologic condition that is responsible for major healthcare problems worldwide and costing billions of dollars annually. Insulin replacement therapy has been used in the clinical management of diabetes mellitus for more than 84 years. The present mode of insulin administration is by the subcutaneous route through which insulin is presented to the body in a non-physiological manner having many challenges. Hence novel approaches for insulin delivery are being explored. Challenges to oral route of insulin administration are: rapid enzymatic degradation in the stomach, inactivation and digestion by proteolytic enzymes in the intestinal lumen and poor permeability across intestinal epithelium because of its high molecular weight and lack of lipophilicity. Liposomes, microemulsions, nanocubicles, and so forth have been prepared for the oral delivery of insulin. Chitosan-coated microparticles protected insulin from the gastric environment of the body and released intestinal pH. Limitations to the delivery of insulin have not resulted in fruitful results to date and there is still a need to prepare newer delivery systems, which can produce dose-dependent and reproducible effects, in addition to increased bioavailability.


2021 ◽  
Vol 22 (15) ◽  
pp. 7931
Author(s):  
Ning Liu ◽  
Shiqiang Sun ◽  
Pengjie Wang ◽  
Yanan Sun ◽  
Qingjuan Hu ◽  
...  

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a metabolite of tryptophan and is reported to modulate the development and neurogenesis of the enteric nervous system, gut motility, secretion, inflammation, sensation, and epithelial development. Approximately 95% of 5-HT in the body is synthesized and secreted by enterochromaffin (EC) cells, the most common type of neuroendocrine cells in the gastrointestinal (GI) tract, through sensing signals from the intestinal lumen and the circulatory system. Gut microbiota, nutrients, and hormones are the main factors that play a vital role in regulating 5-HT secretion by EC cells. Apart from being an important neurotransmitter and a paracrine signaling molecule in the gut, gut-derived 5-HT was also shown to exert other biological functions (in autism and depression) far beyond the gut. Moreover, studies conducted on the regulation of 5-HT in the immune system demonstrated that 5-HT exerts anti-inflammatory and proinflammatory effects on the gut by binding to different receptors under intestinal inflammatory conditions. Understanding the regulatory mechanisms through which 5-HT participates in cell metabolism and physiology can provide potential therapeutic strategies for treating intestinal diseases. Herein, we review recent evidence to recapitulate the mechanisms of synthesis, secretion, regulation, and biofunction of 5-HT to improve the nutrition and health of humans.


Nutrients ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 2147 ◽  
Author(s):  
Michele Dei Cas ◽  
Riccardo Ghidoni

The yellow pigment curcumin, extracted from turmeric, is a renowned polyphenol with a broad spectrum of health properties such as antioxidant, anti-inflammatory, anti-cancer, antidiabetic, hepatoprotective, anti-allergic, anti-dermatophyte, and neuroprotective. However, these properties are followed by a poor pharmacokinetic profile which compromises its therapeutic potential. The association of low absorption by the small intestine and the extensive reductive and conjugative metabolism in the liver dramatically weakens the oral bioavailability. Several strategies such as inhibition of curcumin metabolism with adjuvants as well as novel solid and liquid oral delivery systems have been tried to counteract curcumin poor absorption and rapid elimination from the body. Some of these drug deliveries can successfully enhance the solubility, extending the residence in plasma, improving the pharmacokinetic profile and the cellular uptake.


1990 ◽  
Vol 259 (3) ◽  
pp. G443-G452 ◽  
Author(s):  
L. C. Read ◽  
A. P. Lord ◽  
V. Brantl ◽  
G. Koch

beta-Casomorphins (beta-CMs) derived from milk beta-casein may exert various opiate activities in milk-fed infants. To assess the physiological significance of beta-CMs as a source of circulating opioids in infants, we measured absorption rates of several beta-CMs under near-physiological conditions using in situ autoperfused lamb intestine. The naturally occurring beta-CMs, beta-CM-7 and beta-CM-4-amide, were absorbed readily into blood with no transfer into lymph. Uptake peaked within several minutes of the luminal infusion of peptide but then declined sharply and stopped within a further 10-15 min. The recovery in blood, intestinal contents, and tissue at the end of the 30-min experiment was less than 1% of the infused dose. The low recovery was due to rapid proteolysis based on in vitro studies that demonstrated half-lives of less than 5 min in lamb blood, luminal contents, and lymph. The synthetic dipeptidyl peptidase IV-resistant analogue beta-[D-Ala2]CM- 4-amide was stable during incubation in blood, lymph, or luminal contents and was absorbed into blood at rates that were maximal within several minutes and remained steady for the 30-min period. We conclude that although natural beta-CMs are transferred across the lamb small intestine, rapid degradation within the intestinal lumen, gut epithelium, and blood would prevent entry into the circulation under normal conditions. Val-beta-CM-7, a putative stable precursor, had similar stability and kinetics of absorption to beta-CM-7, results that exclude Val-beta-CM-7 as a stable precursor for delivery of beta-CMs to the circulation. Essentially identical results to those in lambs were obtained in 7-day-old piglets.


Sign in / Sign up

Export Citation Format

Share Document