Inhibition of active lymph pump by simulated microgravity in rats

2006 ◽  
Vol 290 (6) ◽  
pp. H2295-H2308 ◽  
Author(s):  
Anatoliy A. Gashev ◽  
Michael D. Delp ◽  
David C. Zawieja
Keyword(s):  
Thoracic Duct ◽  
Simulated Microgravity ◽  
Fluid Volume ◽  
Tissue Fluid ◽  
Pressure Gradients ◽  
Potent Inhibition ◽  
Detailed Evaluation ◽  
Lymphatic Pumping ◽  
Head Neck ◽  
Normal Head

During spaceflight the normal head-to-foot hydrostatic pressure gradients are eliminated and body fluids shift toward the head, resulting in a diminished fluid volume in the legs and an increased fluid volume in the head, neck, and upper extremities. Lymphatic function is important in the maintenance of normal tissue fluid volume, but it is not clear how microgravity influences lymphatic pumping. We performed a detailed evaluation of the influence of simulated microgravity on lymphatic diameter, wall thickness, elastance, tone, and other measures of phasic contractility in isolated lymphatics. Head-down tail suspension (HDT) rats were used to simulate the effects of microgravity. Animals were exposed to HDT for 2 wk, after which data were collected and compared with the control non-HDT group. Lymphatics from four regional lymphatic beds (thoracic duct, cervical, mesenteric, and femoral lymphatics) were isolated, cannulated, and pressurized. Input and output pressures were adjusted to apply a range of transmural pressures and flows to the lymphatics. Simulated microgravity caused a potent inhibition of pressure/stretch-stimulated pumping in all four groups of lymphatics. The greatest inhibition was found in cervical lymphatics. These findings presumably are correlated to the cephalic fluid shifts that occur in HDT rats as well as those observed during spaceflight. Flow-dependent pump inhibition was increased after HDT, especially in the thoracic duct. Mesenteric lymphatics were less strongly influenced by HDT, which may support the idea that lymph hydrodynamic conditions in the mesenteric lymphatic during HDT are not dramatically altered.

Chronic lymph flow and transcapillary fluid flux during angiotensin II hypertension

1990 ◽  
Vol 259 (6) ◽  
pp. R1205-R1213 ◽  
Author(s):  
J. Valenzuela-Rendon ◽  
R. D. Manning
Keyword(s):  
Angiotensin Ii ◽  
Plasma Protein ◽  
Thoracic Duct ◽  
Protein Transport ◽  
Lymph Flow ◽  
Fluid Volume ◽  
Thoracic Duct Lymph ◽  
Ang Ii ◽  
Fluid Flux ◽  
Duct Lymph

The roles of the transvascular fluid flux and lymph flow in the distribution of extracellular fluid volume during angiotensin II (ANG II) hypertension were evaluated in 11 conscious dogs. Similarly, the factors regulating the distribution of plasma protein across the microvasculature were assessed. By the second day of ANG II infusion, the thoracic duct lymph flow had increased 58% above control, transcapillary fluid flux had increased 45%, and plasma volume, sulfate space, and interstitial fluid volume remained close to control. In addition, the thoracic duct lymph protein transport had increased 34%, and the accompanying increase in transcapillary protein flux prevented any change in plasma protein mass. Also, at this time, the lymph flow and protein transport from subcutaneous tissue in the hind limb were not increased, and the permeability-surface area product of this region decreased 40%. The origin of the increased thoracic duct lymph flow on day 2 probably was from the splanchnic bed. In conclusion, the increased lymph flow during ANG II hypertension compensated for the increase in transcapillary fluid flux, thus preventing edema formation.

Importance of lymph vessels in the transcapillary fluid balance in the gingiva studied in a transgenic mouse model

2010 ◽  
Vol 299 (2) ◽  
pp. H275-H283 ◽  
Author(s):  
Lilian Ephrem Mkonyi ◽  
Athanasia Bletsa ◽  
Inge Fristad ◽  
Helge Wiig ◽  
Ellen Berggreen
Keyword(s):  
Fluid Balance ◽  
Volume Expansion ◽  
Interstitial Fluid ◽  
Oral Bacteria ◽  
Fluid Volume ◽  
Tissue Fluid ◽  
Edema Formation ◽  
Steady State Condition ◽  
Lymph Vessels

The gingiva is frequently challenged by oral bacterial products leading to inflammatory responses such as increased fluid filtration and edema formation. The role of initial lymphatics for transcapillary fluid balance in the gingiva is unknown and was therefore investigated in genetically engineered K14-VEGF receptor 3-Ig (K14) lymphedema mice. The mutant mice demonstrated a total lack of lymphatics in the gingiva, whereas lymphatics were found in the submucosal parts of the alveolar mucosa, although they were almost completely absent in the mucosa. In wild-type (WT) mice, lymphatic vessels were detected in mucosal and submucosal parts of the alveolar mucosa. Interstitial fluid pressure (Pif) measured with micropipettes was increased in the gingiva of K14 mice in the normal situation ( P < 0.001) and after inflammation ( P < 0.01) induced by lipopolysaccharide from the oral bacteria Porphyromonas gingivalis compared with WT littermates. Fluid volume expansion caused a >75% increase in interstitial fluid volume followed by a drop in Pif after recovery in both strains. Continuous measurements during the expansion showed an increase in Pif followed by a decline, suggesting that compliance is increased after the disruption of the extracellular matrix during edema formation. In the alveolar mucosa, no strain differences were observed in Pif in the normal situation or after fluid volume expansion, suggesting that lymph vessels in the mucosa are not critical for tissue fluid regulation in any situation. Our study demonstrates an important role of gingival lymphatics in transcapillary fluid balance in the steady-state condition and during acute perturbations.

Pulmonary fluid extraction and osmotic conductance, ςK, measured in vivo

1998 ◽  
Vol 84 (3) ◽  
pp. 769-781 ◽  
Author(s):  
Joseph M. Karch ◽  
Jen-Shih Lee
Keyword(s):  
Osmotic Pressure ◽  
Lung Tissue ◽  
Isotonic Saline ◽  
Fluid Volume ◽  
Density Change ◽  
Hypertonic Solution ◽  
Tissue Fluid ◽  
Fluid Extraction ◽  
Fluid Filtration

The change in aortic blood density in an in vivo rabbit preparation was measured to assess fluid movement at the pulmonary capillaries caused by infusion of hypertonic solution (NaCl, urea, glucose, sucrose, or raffinose in isotonic saline) into the vena cava over 20 s. The hypertonic disturbance increased the plasma osmotic pressure by ≤30 mosmol/l. The density change indicates that the fluid extraction from the lung tissue was completed within 10 s. It was followed by a fluid filtration into the lung tissue and then an extraction and filtration from peripheral organs. An exchange model with flow dispersion yields two equations to estimate the osmotic conductance (ς K; where ς is the reflection coefficient of the test solute and K is the filtration coefficient including the total capillary surface area), and the tissue fluid volume from the area and first moment of the measured density change over the extraction phase. The values of ς K are 1.40 ± 0.11, 1.00 ± 0.10, 1.71 ± 0.10, 2.60 ± 0.23, and 3.73 ± 0.34 (SE) ml ⋅ h−1 ⋅ mosmol−1 ⋅ l ⋅ g−1for NaCl, urea, glucose, sucrose, and raffinose, respectively. Consistent with the model prediction, the tissue fluid volume (0.28 ± 0.04 ml/g wet lung tissue) was independent of the solute used. This value suggests that all fluid spaces in the alveolar septa participate in the process of fluid extraction due to an increase in plasma osmotic pressure.

Lymph Flow in the Thoracic Duct of Conscious Dogs During Lymphatic Pump Treatment, Exercise, and Expansion of Extracellular Fluid Volume

2008 ◽  
Vol 6 (1) ◽  
pp. 3-13 ◽  
Author(s):  
H. Fred Downey ◽  
Preethi Durgam ◽  
Arthur G. Williams ◽  
Amol Rajmane ◽  
Hollis H. King ◽  
...  
Keyword(s):  
Thoracic Duct ◽  
Extracellular Fluid ◽  
Lymph Flow ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Conscious Dogs ◽  
Lymphatic Pump Treatment

Scanning Electron Microscopic Study of the Cell Surface

1969 ◽  
Vol 27 ◽  
pp. 36-37 ◽  
Author(s):  
Toichiro Kuwabara
Keyword(s):  
Tissue Fluid ◽  
Biological Application ◽  
Biological Structure ◽  
Electron Microscopic ◽  
Surface Appearance ◽  
Minute Amount ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
True Structure ◽  
Scanning Electron

Although scanning electron microscopy has a great potential in biological application, there are certain limitations in visualization of the biological structure. Satisfactory techniques to demonstrate natural surfaces of the tissue and the cell have been reported by several investigators. However, it is commonly found that the surface cell membrane is covered with a minute amount of mucin, secretory substance or tissue fluid as physiological, pathological or artefactual condition. These substances give a false surface appearance, especially when the tissue is fixed with strong fixatives. It seems important to remove these coating substances from the surface of the cell for demonstration of the true structure.

Measurement of Pancreatic Enzymes in Human Thoracic Duct Lymph

1960 ◽  
Vol 38 (6) ◽  
pp. 954-956 ◽  
Author(s):  
Allan E. Dumont ◽  
John H. Mulholland
Keyword(s):  
Thoracic Duct ◽  
Pancreatic Enzymes ◽  
Thoracic Duct Lymph ◽  
Duct Lymph
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