Vascular Transport Research Articles

Altered arterial ion transport and its reversal in aldosterone hypertensive rat.

Alterations in vascular ionic metabolism preceded the onset of elevated blood pressure in the aldosterone-treated rat. Increases in 42K+ and 36Cl- turnover in the aorta and femoral artery were detected as early as 1 wk after the start of aldosterone infusion. These vascular changes were completely reversed after a 3-wk recovery period. An increased sensitivity to the effect of norepinephrine (NE) on aortic 42K+ turnover was also observed prior to a significant rise in systolic blood pressure. Enhanced sodium transport was also found in vessels from hypertensive rats infused with aldosterone for 4 wk. The potassium-sensitive component of the 24Na+ efflux was significantly elevated in vessels from hypertensives. This increase in sodium pump activity appeared to compensate for an increase in passive membrane permeability to sodium in that cell sodium levels were not altered by aldosterone treatment. A more rapid increase in 42K+ turnover occurred in aorta from aldosterone-treated rats when extracellular calcium was removed. Therefore, an impaired ability of calcium-dependent processes to adequately stabilize the vascular smooth muscle membrane may contribute to altered vascular ion transport. It is concluded that altered vascular electrolyte metabolism is an important pathogenic mechanism in the development of aldosterone-induced hypertension in the rat.

Urea nutrition of young maize and sugar-beet plants with emphasis on ionic balance and vascular transport of nitrogenous compounds.

In a pot trial, maize cv. Prior and sugarbeet cv. Polyrave were given N as urea or ammonium. There was no significant difference between DM producton in either spp. with the different N sources, although plant N content was increased with N supplied as ammonium. Root cumulative net proton extrusion closely agreed with calculated values for net absorption of cations, indicating that urea was absorbed intact, at a rate sufficient for growth. Xylem exudate was free from urea and NH3-N suggesting metabolism in the roots. Urea appeared to be assimilated other than by enzymic breakdown. (Abstract retrieved from CAB Abstracts by CABI’s permission)

System analysis of vascular membrane water and protein transport: General method and application to canine hindquarters

A system analysis is developed to examine interdependencies of parameters and variables in lymph flux analysis experiments where lymph flux ( L) and lymph/plasma protein concentration ratios ( R = C L C p ) are measured. Homoporosity and right circular cylindrical pores are assumed for simplicity, but complex models are subject to similar methods. Parameters and variables analyzed include reflection coefficient (σ), hydraulic-conductivity surface product ( L p S), permeability surface product ( PS), protein clearance ( LR), permeative protein clearance ( D), convective protein clearance ( B), and fractional permeative protein transport (Fr D). Insights gained are numerous and include: Uncertainties or variations in σ produce magnified and vectorially similar variations in B for loose membranes, but very much smaller and vectorially opposite variations in B in tight membranes. Although errors in R may lead to large errors in some parameters such as PS, these erroneous values may themselves yield very small errors in other computed membrane-solution variables such as Fr D. Hence, Fr D is fairly insensitive to errors in R which may arise when experiments are not precisely at steady-state conditions. Moreover, even an unrealistic 100% error in R transmits virtually no error to computed σ in tight membranes. D rises significantly as L rises, accounting for nearly all the increase in LR for tight membranes. Such an analysis is useful in planning experimental design, and can be used to determine internal consistency of more complex transport models.

Central venous bubbles and mixed venous nitrogen in goats following decompression.

Decompression of awake goats from saturation at 1, 2, and 3 ATA of air has been carried out using ultrasonic Doppler bubble detection, central venous blood inert gas measurement, and cardiac output measurement. The results of these experiments indicate that the decrease in nitrogen elimination rate as an apparent result of decompression cannot be due to excessive cardiac output or mass transport of a large amount of inert gas to the lungs as bubbles. Rather, the rapid drop in mixed venous nitrogen content is consistent with a generalized decrease in tissue-to-blood nitrogen elimination. This in turn appears to be due to a cardiovascular response to the decompression insult as was previously reported for dogs (D'Aoust et al., J. Appl. Physiol. 41: 348--355, 1976) at 1, 2, and 3 ATA; addition of ultrasonic Doppler monitoring and cardiac output in the present studies allowed measurement of the degree of latency in the appearance of bubbles at a central venous location. This time period includes that required for bubble formation, growth, and vascular transport of the bubbles to the Doppler detector. All results of these studies are consistent with the interpretation that due to a decompression insult, which probably includes bubble formation, some degree of hemostasis, and other hematologic sequelae, the transport of tissue inert gas to the capillary venous blood is retarded, thus providing the rapid apparent decrease in mixed venous blood inert gas content. These results demonstrate what is most likely a general response to a severe but not crucial decompression by the cardiovascular system.

Element and Energy Flows Through Colonies of the Leaf-Cutting Ant, Atta colombica, in Panama

Element and Energy Flows Through Colonies of the Leaf-Cutting Ant, Atta colombica, in Panama

Pressure, serotonin, and histamine effects on lung multiple-indicator curves in sheep

ARTICLESPressure, serotonin, and histamine effects on lung multiple-indicator curves in sheepT. R. Harris, K. L. Brigham, and R. D. RowlettT. R. Harris, K. L. Brigham, and R. D. RowlettPublished Online:01 Feb 1978https://doi.org/10.1152/jappl.1978.44.2.245MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByTransit time dispersion in the pulmonary arterial treeAnne V. Clough, Steven T. Haworth, Christopher C. Hanger, Jerri Wang, David L. Roerig, John H. Linehan, and Christopher A. Dawson1 August 1998 | Journal of Applied Physiology, Vol. 85, No. 2Lung water and vascular permeability-surface area in premature newborn lambs with hyaline membrane disease.Circulation Research, Vol. 60, No. 6Changes in lung vascular permeability after heart-lung transplantationJournal of Surgical Research, Vol. 39, No. 4Lung vascular transport at controlled pressures with reduced coronary flow in sheepMicrovascular Research, Vol. 30, No. 2Pulmonary edema formation with myocardial infarction and left atrial hypertension: intravascular and extravascular pulmonary fluid volumes.Circulation, Vol. 68, No. 1Effects of red cell exchange on calculated sheep lung vascular permeability ot 14C-urea and 14C-thioureaRespiration Physiology, Vol. 49, No. 1The pathogenesis of pulmonary edemaProgress in Cardiovascular Diseases, Vol. 23, No. 1Indicator dilution lung water and vascular permeability in humans. Effects of pulmonary vascular pressure.Circulation Research, Vol. 44, No. 4 More from this issue > Volume 44Issue 2February 1978Pages 245-253 Copyright & PermissionsCopyright © 1978 the American Physiological Societyhttps://doi.org/10.1152/jappl.1978.44.2.245PubMed344291History Published online 1 February 1978 Published in print 1 February 1978 Metrics

Manual Manipulation to Teach Plant Tissues

Research Article| January 01 1978 Manual Manipulation to Teach Plant Tissues Sylvia S. Mader Sylvia S. Mader Search for other works by this author on: This Site PubMed Google Scholar The American Biology Teacher (1978) 40 (1): 39–41. https://doi.org/10.2307/4446131 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Sylvia S. Mader; Manual Manipulation to Teach Plant Tissues. The American Biology Teacher 1 January 1978; 40 (1): 39–41. doi: https://doi.org/10.2307/4446131 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentThe American Biology Teacher Search This content is only available via PDF. Copyright 1978 National Association of Biology Teachers Article PDF first page preview Close Modal You do not currently have access to this content.

Studies on Morphogenesis in Rice Plant : IX. On the structure of vascular bundles and phloem transport in the spikelet

Climbing from the pedicel up into the rachilla, the vascular bundle of the rice spikelet swells in bowl-shape and subsequently piller-shape, branching off the bundles of spikelet organs (Fig. 1 and 3). In the swelling bundle of the rachilla, ramificated xylem and phloem are thrown in confusion, in which tracheids, sieve elements, parenchyma cells and thick-walled cells elaborate a formidable mosaic structure(Figs. 2, 4, 5, 6, 7, 9 and 10). It may be supposed on this structure that, by metabolic activity of the parenchyma cells, water in the sieve elements is extracted out and exuded actively into the tracheids in order to be transpired from the lemma and palea, so that the numerous sieve elements with reduced turgor pressure pump up the sieve current from the pedicel and pump it out toward the dorsal bundle of the ovary. It the dorsal bundle, large xylem sits on the main passway of assimilates from phloem via nucellar projection into endodermis (Fig. 12 and 13), but barium chloride absorbed by the roots does not go up via the vessels of this xylem in normal outdoor condition. This structure might present us with a suggestion that the vessels function in normal condition as drainpipes in order to control the turgor pressure of the ovary and the sieve elements (Fig. 14).

Pulmonary vascular transport in sheep: A mathematical model

We are developing a mathematical description of passive transvascular fluid and protein exchange. The transport model includes vascular membrane characteristics, i.e., “equivalent” pore sizes and numbers and membrane thickness, as well as the physiological variables of microvascular hydrostatic pressure ( P mv), perimicrovascular hydrostatic pressure, and plasma protein molecular sizes and concentrations. We are using the model to investigate the sensitivity of each of the membrane characteristics and physiological variables upon the pulmonary transvascular exchange in the steady state. For the sheep lung, we measure P mv relative to the left atrium, then assume a linear pressure distribution over the measured height of the lung for constant density and vascular membrane characteristics. Theoretical results for the total lymph/plasma concentration ratios of albumin and “globulin” as well as the lymph flow fractions relative to baseline lymph flow rate were obtained from the model as a function of the referenced P mv over the range 10–40 mm Hg. Results have been obtained for various models of membrane characteristics. The theoretical results of lymph/plasma ratios and lymph flow fractions were compared with the experimentally measured values from unanesthetized sheep. A multiplepore model was found that included a small pore system which completely sieved the smallest molecule investigated (albumin, R p = 34 A ̊ ), an intermediate-sized pore of 125 Å radius, and a few large pores of 1000 Å radius. The theoretical results from this model were found to compare with the experimental results from several sheep for the P mv range investigated.

Vascular structure and distribution of vascular pathogens in cotton

Vascular transport patterns in cotton cultivars that are differentially resistant to Venticillium or Fusarium wilt were compared after the introduction of vinyl particles, spores or eosin dye into severed roots or stems. Spores and particles were effectively screened out of the transpiration stream by reticulate-scalariform end walls that occur periodically in the xylem vessels. Although spore trapping is an essential first step in the loicalization of vascular infections, innate vessel length is apparently not a differentiating factor in resistance, for differences in spore uptake distances were minor and not related to relative wilt resistance or susceptibility of the cultivars. Similarly, in all cultivars dye moved laterally from a single rootlet into essentially all the leaf bases. Therefore, differences in degree of articulation of vessels are ruled out as a possible determinant in resistance. When vinyl particle suspensions were taken up into the vascular elements of plants of different ages, the particle passage distances as plants matured. The increase in passage distances was compatible in all cultivars are therefore not related to resistance.

Concepts of residence time distribution applied to the indicator-dilution method.

ArticleConcepts of residence time distribution applied to the indicator-dilution method.L B Wingard Jr, T Chorbajian, and S J GallaL B Wingard Jr, T Chorbajian, and S J GallaPublished Online:01 Aug 1972https://doi.org/10.1152/jappl.1972.33.2.264MoreSectionsPDF (3 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByResidence times of polydisperse dilute suspensions in sheared and extensional flowsPhysics of Fluids, Vol. 34, No. 5Cardiac output and systemic transit time dispersion as determinants of circulatory mixing time: a simulation studyMichael Weiss1 August 2009 | Journal of Applied Physiology, Vol. 107, No. 2Determination of rat cerebral cortical blood volume changes by capillary mean transit time analysis during hypoxia, hypercapnia and hyperventilationBrain Research, Vol. 454, No. 1-2Model-free deconvolution techniques for estimating vascular transport functionsInternational Journal of Bio-Medical Computing, Vol. 14, No. 5Experimental air embolism of the brain: an analysis of the technique in the rat.Stroke, Vol. 13, No. 6Shunt Quantification by Mathematical Analysis of Indicator Dilution Curves24 July 2018 | Catheterization and Cardiovascular Diagnosis, Vol. 4, No. 2[43] Modulations of substrate entry into cellsA probabilistic model for tracer distribution in multiphase spatially inhomogeneous transport systemsJournal of Statistical Physics, Vol. 11, No. 6Dispersion of Indicator Measured from Microvessels of Cat MesenteryCirculation Research, Vol. 35, No. 4 More from this issue > Volume 33Issue 2August 1972Pages 264-75 https://doi.org/10.1152/jappl.1972.33.2.264PubMed4559942History Published online 1 August 1972 Published in print 1 August 1972 Metrics

Transport of large molecules from plasma to interstitial fluid and lymph in dogs.

Transport of large molecules from plasma to interstitial fluid and lymph in dogs.

Stria vascularis of deaf Hedlung mink. Light and electron microscopic studies of vascular insufficiency.

The stria vascularis of deaf Hedlund mink is atrophic and its vascular supply is abnormally sluggish. Its vascular pattern is simpler than normal because many normal connecting vessels disappear during maturation. Ferritin particles provide a convenient means of studying vascular transport by electron microscopy. Injected ferritin does not enter strial vessels in Hedlund mink. Intravascular clotting and endothelial swelling were observed in these vessels.

Vascular Transport and its Significance in Plant Growth

Vascular Transport and its Significance in Plant Growth

Effect of capillary pressure and plasma protein on development of pulmonary edema.

Effect of capillary pressure and plasma protein on development of pulmonary edema.

Systemic Pesticides in Woody Plants: Uptake

Uptake in this discussion involves the movement of systemics from the surface of the plant into the points at which vascular transport in the phloem or xylem is initiated. This movement entails (1) adsorption, (2) penetration and (3) non-vascular transport phenomena. The uptake may occur through (a) roots, (b) stems or (c) leaves, and involve cationic, anionic or unionized chemicals.

Histopathological studies on cutaneous reactions to the bites of various arthropods.

Summary and Discussion The morphology exhibited in the sections of arthropod bite reactions permits a dynamic interpretation. In the search for the blood meal, the biting mechanism of the arthropod appears to penetrate through the epidermis with minimal difficulty. Some spreading factor in the saliva is suggested by the rapid spread of the tissue reaction. The perivascular phases of the reaction also suggest a rapid vascular transportation of the material injected. The sensitivity of an individual to the bite of a given arthropod influences the intensity of the inflammatory response. However, an individual may be sensitive to one arthropod and insensitive to the bites of others. The insensitive individual who develops no clinical bite reaction may be bitten without being aware of it. The histological studies of Boltz (1951) of the skin reactions following injections of needle puncture show that the changes in the skin following a bite by an arthropod is not one of simple “mechanical” puncture even in a non-reactive individual. The persistent late nodular response may be due to the intrinsic nature of the bite (including retained cuticular fragments?) or to a neurodermatitic response secondary to the scratch reaction to itching. Histopathologic methods are valuable in the study of bite reactions. Improvements such as vacuum freeze drying technics and histochemical studies may permit more detailed studies of the variations in the cellular response of the individual to the bites of arthropods. With better fixation technics it may be possible to pick up fine bodies retained after the insect bite. Improvement in the technic of study of the biting parts in situ, will make possible observations relating to the effect of the artificially induced retention of a piece of the biting apparatus within the skin. It is also possible that isotopic studies with other isotopes and more refined autoradiographic technics may enable us to follow the path of the bite more accurately. Progress in the study of the peripheral mechanisms of reaction of Compound F deposited locally may also help in the analysis of the bite reaction. With the bite reaction of an individual determined, it should then be possible to study in detail local and systemic factors which may modify some parts of the bite reaction, as for example, the vascular response, the inflammatory cell response, the degree of pruritus, additive local trauma, etc.

Investigations on the Pathogenesis of Tetanus III

Summary and Conclusions In this and previous communications, investigations on the pathogenesis of tetanus have been reported. The theories of Courmont and Doyon, Meyer and Ransom and Abel have been subjected to experimental tests. We believe to have established the following facts: Tetanal toxin does not reach the C-N-S directly by way of the circulation. This follows from an observation referred to as the R-(route) phenomenon. It was found that the amount of circulating antitoxin which protects animals from death is determined by the route of introduction of the toxin. The same test-dose of toxin, when injected by the intracutaneous or intramuscular routes, requires up to 80 times more antitoxin than after intravenous injection. This result is obviously incompatible with the assumption that the toxin reaches the C-N-S from the tissue after absorption into the circulation.Tetanus cannot be explained by an action of the toxin on the sensory nerve-endings (Courmont and Doyon). Section of the posterior spinal nerve-roots does not influence the R-phenomenon or local tetanus.Tetanus cannot be explained by the activity of a secondary toxic substance formed in the muscle (Courmont and Doyon) or in the C-N-S (Firor, Lamont and Shumacker). Transverse lesions of the dorsal cord, followed by intravenous injection of antitoxin and intramuscular injection of toxin into one hind leg, confines tetanus to the lower extremities and considerably prolongs the survival-time of the experimental animals. This shows that generalized tetanus cannot be explained by a vascular transport of a secondary toxic substance to higher levels of the C-N-S.Tetanal toxin reaches the C-N-S by way of the motor nerves. The R-phenomenon disappears after section of the peripheral nerves or anterior roots.Tetanal toxin spreads within the C-N-S. As mentioned under the third conclusion, after intravenous injection of antitoxin, intramuscular injection of toxin into one hind leg and transverse lesion of the cord, tetanus remains confined to the lower extremities. This shows that interruption of the neural pathways within the cord prevents the passage of the toxin to higher levels of the C-N-S. Moreover, the appearance of tetanus in both hind legs proves the migration of the toxin from one side of the cord to the other.Local tetanus is of central origin. Under optimal experimental conditions antitoxin is 80 times more potent by the intraventricular than the intravenous route in preventing local tetanus in the hind leg. Since the possibility could be excluded that the intraventricularly injected antitoxin reaches the myoneural junction by way of the nerve this experiment shows conclusively that local tetanus is due to an action of the toxin on the C-N-S.Our experiments therefore confirm the nerve-carriage theory of Meyer and Ransom in all essential points.Our results provide conclusive evidence for the existence of the blood-C-N-S barrier. Since tetanal toxin is extremely toxic when injected into the lumbar cord its inability to reach the C-N-S by way of the circulation can be explained only by an impermeability of the capillaries of the C-N-S to the toxin. This, in connection with the electro-negative charge of tetanal toxin, confirms the rule of Friedemann and Elkeles according to which the blood-C-N-S barrier is impermeable to electro-negative substances.It is now established that an inanimate substance can be transmitted within the nerve to the central nervous system. The implications of this fact for the pathogenesis of neurotropic virus diseases are discussed.