Assessing perfusion and capillary permeability changes induced by a VEGF inhibitor in human tumor xenografts using macromolecular MR imaging contrast media.
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Animals↗
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Results for “Capillary Permeability”
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The application of brain capillary permeability coefficient measurements to pathological conditions and the selection of agents which cross the blood-brain barrier.
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Animals↗
Quantification of capillary permeability to macromolecular magnetic resonance imaging contrast media in experimental mammary adenocarcinomas.
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Adenocarcinoma↗
Effect of vasodilation and flow rate on capillary permeability surface product and interstitial space size in the coronary circulation. A frequency domain technique for modeling multiple dilution data with Laguerre functions.
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Animals↗
Effect of vasopressin on ependymal and capillary permeability to tritiated water in cat.
Ependymal cells line the cerebral ventricles forming the interface that separates the cerebrospinal (CSF) and interstitial fluids (ISF). Extracellular molecules move between ependymal cells, whereas lipid soluble molecules pass both between and through cells. We measured the transfer of tritiated water (TOH) from CSF to blood across the ependymal and capillary interfaces by ventriculocisternal (VC) steady-state tissue clearance. Adult cats anesthetized with pentobarbital sodium underwent VC perfusion with the extracellular marker [14C]sucrose and TOH added to the artificial CSF. Brain tissue was analyzed for depth of penetration of the isotopes into periventricular gray matter. We found that TOH distribution space was lower than expected from water content measurements, whereas sucrose space was normal. Using VC steady-state equations we calculated an ependymal permeability that was similar to the permeability of the cerebral capillary. When arginine vasopressin (AVP) was added to the perfusate in different amounts, both capillary transfer times and ependymal permeability increased. Our results show that the ependyma may be important in water movement in the brain and support the suggestion that AVP influences water exchange in mammalian brain tissue.
Animals↗
Documentation of pulmonary capillary permeability in the adult respiratory distress syndrome accompanying human sepsis.
Current evidence suggests that pulmonary edema accompanying human sepsis may result either from changes in the serum oncotic and hydrostatic pressures or an increase in the permeability of the pulmonary microvasculature. In this study, we compared the "clearance" of injected 131I-labeled human serum albumin from blood to bronchoalveolar secretions in intubated patients with pulmonary edema secondary to sepsis or myocardial infarction. A significantly increased mean +/- SE clearance of the radionuclide was seen in patients with sepsis (0.34 +/- 0.03 ml per hour) compared to those with myocardial infarction (0.043 +/- 0.008 ml per hour) (P less than 0.001), although both groups had similar degrees of edema on chest radiographs. Because the patients with sepsis had no severe decrease in serum oncotic pressure (18.4 +/- 5.0 mm Hg) or evidence of left heart failure, as determined by the pulmonary wedge pressure (11.0 +/- 6.8 mm Hg), we concluded that the genesis of the pulmonary edema in sepsis was due to an increase in pulmonary microvascular permeability, as measured by the increased clearance of 131I-labeled human serum albumin.
Adult↗
[Capillary permeability under the action of the naphthene hydrocarbons of naphtalane].
During the experiments on rats, the authors studied the influence of cyclopentanoperhydrofenantren of naphthenes; which is one of the active initials of the naphthalan, on the two-side vessel permeability for the radio active phosphorus. After repeated injection of the agent, the increase of the permeability for the indicator is noted. It is supposed that the mechanism of the action is caused by the inclusion of the agent to the biosynthesis of hormones of the suprarenals.
Animals↗
Studies on the pulmonary capillary permeability after induced microembolism.
Pulmonary microembolization was induced by infusion of thrombin during inhibition of the fibrinolytic system. After embolization cardiac output decreased, pulmonary vascular resistance and pulmonary arterial pressure increased. There was a transient decrease in PaO2. Immediately after embolization there was an increased permeability indicated by tremendous increase in lymph flow with a constant lymph/plasma protein ratio. The lymph/plasma ratio for hemoglobin and for FITC-Dextran (mw 150 000) also increased indicating leakage of large molecules. The increased permeability was accompanied by a significant increase in extra-vascular lung-water as measured both with the thermal conductivity and the dry/wet weight method.
Animals↗
Complement activation and increased alveolar-capillary permeability after major surgery and in adult respiratory distress syndrome.
The concentrations of C3a des Arg were measured in bronchoalveolar fluid (BAL) and plasma from 12 patients with adult respiratory distress syndrome (ARDS). Compared with 32 controls, all patients had increased BAL fluid levels (p less than .001), and nine of 12 had increased plasma levels (p less than .001) of this split product from the third complement component. Reduced total hemolytic activity (CH50) in serum was seen in five patients (p less than .01). As an indication of damage to the alveolar-capillary barrier, ten of the 12 ARDS patients had elevated albumin concentrations in BAL fluid (p less than .001). These signs of complement activation and lung tissue damage are not specific for ARDS. Thus, in 15 patients investigated preoperatively and postoperatively, we found that major surgery induced a significant increase of BAL fluid C3a (p less than .01) and plasma C3a (p less than .02), a significant reduction of CH50 (p less than .001), and a significant increase of BAL fluid albumin (p less than .02). Similar values of CH50 and plasma C3a were seen in ARDS and after surgery (p greater than .05). Of the 12 ARDS patients, eight had increased BAL fluid concentrations of C3a (p less than .001), and ten had increased BAL fluid levels of albumin (p less than .001) compared with the post-surgical patients. Measuring complement consumption in blood by these techniques is of limited value in ARDS due to the lack of specificity. BAL fluid albumin has a similar degree of sensitivity and specificity for ARDS as does BAL fluid C3a.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Simultaneous measurements of capillary diffusion and filtration exchange during shifts in filtration-absorption and at graded alterations in the capillary permeability surface area products (PS).
The diffusion exchange of Cr-EDTA, using the single injection indicator diffusion method, was followed simultaneously with estimations of the capillary filtration capacity (CFC) in an "isogravimetric" rat hindquarter preparation during artificial perfusion and maximal dilatation. Measurements were performed at constant flow and during 1) shifts in filtration-absorbtion, 2) alterations of perfused capillary wall area (graded rarification of capillary network by microsphere injection) and 3) during alterations of permeability (i.a. infusion of histamine). At maximal vasodilatation CFC was 0.037 +/- 0.001 ml/min X mmHg X 100 g and PS for Cr-EDTA 5.67 +/- 0.13 ml/min X 100 g. During filtration or absorbtion, Cr-EDTA transfer from vessels to interstitium changed only slightly but the situation may well be different for solute transfer from interstitium to vessels. Alterations in capillary wall area resulted in proportional changes in PS for Cr-EDTA while the CFC changes were always relatively smaller. Histamine increased CFC some threefold with a marked increase in protein transfer, while PS for Cr-EDTA increased only marginally. This histamine effect could be ascribed mainly to an increase in the number of large pores which, because of their relative paucity, are of little importance for small molecular diffusion exchange but highly important for convective and macromolecular exchange.
Absorption↗
Effect of antihistamine-antiserotonin and ganglionic blocking agents upon increased capillary permeability following burn trauma.
Tiny (0.2% TBS), partial thickness, non-contact radiant heat burns in guinea pigs resulted, within 3 hours, in significant edema formation and protein leakage at the site of the injury. Areas of skin distant to the burn also showed an increase in water content but no protein leakage. Pretreatment of the animals with either chlorisondamine hydrochloride or a mixture of methysergide and chlorpheniramine significantly decreased postburn edema formation and protein leakage. Liquid emulsion autoradiography revealed that leakage of protein occurs primarily in the areas of skin adjacent to the panniculus carnosus. The studies suggest that: the increase in vascular permeability that occurs as a consequence of burn injuries is humorally mediated; albumin leakage is limited to the injured tissues; and histamine, serotonin, and presumably catecholamines play significant roles in the development of this phenomenon.
Animals↗
Glomerular capillary permeability in developing canines.
The changes in glomerular permeability that occur during development were assessed in 1- and 6-wk-old canines by analyzing dextran-sieving curves obtained in six animals at each age. The fractional clearance of the smallest dextran molecules (18 A) was 0.97 +/- 0.02 (+/- SE) in both 1- and 6-wk-old animals, and it became progressively less at larger molecular sizes. The sieving curves were consistent with an isosporous model of a glomerular capillary. When axial changes in protein concentration were included in the mathematical model, the apparent pore radius was 62.7 +/- 1.7 and 61.7 +/- 1.69 A in 1- and 6-wk-old puppies, respectively (P greater than 0.7). The effects of developmental changes in hydrostatic pressure and renal blood flow were balanced by the increases in serum protein concentration and filtration fraction leaving the fractional clearances of macromolecules unchanged. In contrast, the total cross-sectional pore area per unit path length (Aw/delta x) increased during this 6-wk period by approximately 7.5-fold (from 1.39 +/- 0.2 to 10.55 +/- 3.0 10(-5) cm, P less than 0.0001), and the ultrafiltration coefficient rose from 0.012 +/- 0.002 to 0.093 +/- 0.012 ml X s-1 X mmHg-1 (P less than 0.0001). The findings reveal constancy of pore size and an increase in total pore area as a function of age. Analysis by classical pore theory yielded similar findings. We conclude that the predominant factor determining the rise in glomerular filtration rate during development is the large increment in Aw/delta x, which in turn is due to increases in the surface area and pore density of the glomerular capillaries.
Animals↗
[Ultrastructure of capillary permeability in human brain tumor: disseminated and metastatic medulloblastoma].
The ultrastructure of the tumor vessels of primary cerebellar, subarachnoidal disseminated and extraneural metastatic medulloblastomas was studied. They were compared with those in glial, nonglial and metastatic brain tumors which have been previously reported. Twelve surgical specimens were examined. Seven tumors were limited to the vermis, the floor of the fourth ventricle and the cerebellar hemispheres. Four gross nodule seedings were demonstrated in the cerebral and spinal subarachnoid space. One metastasis was demonstrated in the subclavicular lymph node. Ultrathin section of those tumors and replica specimens were studied under the transmission electron microscope. The tumor vessels of primary medulloblastoma and glial tumors had nonfenestrated capillaries and were morphologically similar to normal brain capillaries. On the other hand, the tumor vessels of disseminated and metastatic medulloblastoma, nonglial tumors, and metastatic brain tumors had fenestrated capillaries. These findings were anticipated because the arachnoid membrane and lymph nodes have fenestrated capillaries. The presence of fenestration suggests that the tumor vessels of disseminated and metastatic brain tumors resemble the blood vessels found in normal arachnoid membrane and lymph nodes.
Adult↗
[Jaffe's syndrome and anomalies of capillary permeability].
The parallelism between ophthalmoscopy and angiography in the different grade classifications of idiopathic epiretinal membranes is not compulsory: spotty and irregular fluorescein leakage is apparent in many cases, even early. This leakage, who might bring biochemical factors stimulating cellular migration and proliferation could therefore be usually associated with more progression of the membrane.
Adult↗
Lysozyme, intradermal diffusion of india ink and peritoneal capillary permeability in mice.
Hen egg white lysozyme injected intracutaneously into mice inhibits the intradermal diffusion of India Ink. The effect of lysozyme persists in presence of hyaluronidase. Lysozyme injected i.p. into mice inhibits acetic acid (i.p.) induced leakage of Pontamine Sky Blue into the abdominal cavity. The data suggest that lysozyme might be tried for applications outside the microbiological field.
Animals↗
Change in the capillary permeability of the stria vascularis by different methods of death and fixation.
The permeability of the stria vascularis to horseradish peroxidase (HRP) was examined. Ten minutes after an intravenous injection of HRP, 15 guinea pigs were killed and fixed by four different methods: cochleas fixed 3 minutes after decapitation, administration of an overdose of pentobarbital, cochleas fixed for 5 minutes before decapitation, and cochleas fixed immediately after decapitation. In the animals in group 1, HRP leakage was observed in almost all strial vessels (86%), and blood sludging and amorphous HRP reaction product in 98% of strial capillaries. In the animals in group 2, strial capillaries were observed both with noticeable HRP leakage and with no evidence of leakage. Blood sludging was associated with amorphous HRP reaction product, while no blood sludging was associated with granular HRP reaction product. In group 3 animals, only faint or no HRP reaction product was observed in the perivascular spaces. Only 3% of the capillaries had blood sludging. In the animals in group 4, blood sludging but no HRP leakage was observed in almost all capillaries (82%). It is speculated that HRP does not normally leak from the strial capillaries, although many researchers have reported to the contrary. It appears that HRP leaks from the strial capillaries only when acute anoxia or hypotension continues for a few minutes. These conditions induce blood sludging and are followed by the appearance of many marginal folds in these capillaries.
Animals↗
Angioprotective action of calcium dobesilate against reactive oxygen species-induced capillary permeability in the rat.
Calcium dobesilate possesses antioxidant properties in vitro, but the in vivo significance and putative angioprotective role of these properties are undefined. Here, calcium dobesilate was tested in a newly developed in vivo model of microvascular permeabilization induced by reactive oxygen species in the rat peritoneal cavity. In this model, microvascular permeabilization is equated to the rate of Evans blue extravasation toward the peritoneal cavity. Basal Evans blue extravasation (rate constant values ke = 0.0176 +/- 0.0015 h-1) was markedly and significantly increased by reactive oxygen species generated in situ, with: (i) phenazine methosulfate/NADH (delta ke(phenazine methosulfate) = 0.0419 +/- 0.0043 h-1) and (ii) xanthine/xanthine oxidase (delta ke(xo) = 0.0383 +/- 0.0010x h-1). These actions of reactive oxygen species were abolished by locally injected superoxide dismutase (i.p., 300 units/kg). Intraperitoneally given calcium dobesilate (100 mg/kg) inhibited 75-100% of reactive oxygen species-induced Evans blue extravasation. By the intravenous route, calcium dobesilate i.v. (1-50 mg/kg) dose dependently inhibited phenazine methosulfate-induced Evans blue extravasation with an ID50 of 2-5 mg/kg (full inhibition was reached at 20-50 mg/kg). After single oral administration, calcium dobesilate (5-500 mg/kg) dose dependently inhibited phenazine methosulfate-dependent Evans blue extravasation with an ID50 of 50-100 mg/kg (81% inhibition at 500 mg/kg, P < 0.003). After 7 days of oral calcium dobesilate (50 mg/kg once/day) phenazine methosulfate-induced Evans blue peritoneal extravasation was significantly reduced by half. These effects of calcium dobesilate were similar to those observed with a comparative antioxidant molecule, rutin. In conclusion, rat peritoneal microvascular permeability was strongly increased by reactive oxygen species, an effect that was significantly reduced by intraperitoneal, intravenous and oral calcium dobesilate. These results support the hypothesis that the antioxidant properties of calcium dobesilate could play a role in its angioprotective properties in vivo.
Administration, Oral↗
Coronary capillary permeability and tissue volumes for sucrose and water in dogs: a comparison of bolus and constant infusion multiple-indicator methods.
This study was undertaken to determine the accuracy with which heart interstitial and water volumes could be determined from multiple-indicator dilution experiments on the coronary circulation in open-chest dog preparations. Sucrose permeability by extraction calculations was found to average 0.26 +/- 0.02 cm3 . (min . g tissue)-1. The extravascular sucrose volume averaged 0.15 cm3 . g-1 tissue by both multiple-indicator and post-mortem methods. Indicator-dilution tritiated water curves labelled 85% of the post-mortem water content.
Animals↗