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PubMedDate not supplied

[Prognostic significance of the results of measuring skin capillary permeability in the terminal stage of lower limb ischemia].

The paper outlines a procedure for evaluating distal extremity microcirculation, which consists in exposing the examined skin area to negative pressure and in recording the electric resistance of the area in question prior to and after exposure, the permeability of skin capillaries is judged from the value differences. Its predictive value was assessed in patients with terminal lower extremity arterial ischemia.

Amputation, Surgical↗
PubMed1980

Role of iron-binding proteins and enhanced capillary permeability on the accumulation of gallium-67.

We studied the role of the iron-binding proteins transferrin and lactoferrin and of increased capillary permeability on the accumulation of gallium-67 in rabbits. Intramuscular injection of histamine caused accumulation of gallium-67 (injected i.v. as citrate), and of Tc-99m DTPA, at the i.m. injection site. Normal saline and albumin did not. Intramuscular injection of transferrin or lactoferrin similarly caused Ga-67 uptake. No accumulation of Tc-99m DTPA was observed at the site of transferrin injection but there was a slight accumulation at the site of lactoferrin injection. Prior saturation of transferrin or lactoferrin with ferric ion abolished their effect on Ga-67 accumulation. Gallium-67, pre-bound to transferrin vitro, did not accumulate at the site of histamine or transferrin injection, but there was a slight accumulation at the lactoferrin site. Our results suggest that either increased capillary permeability or iron-binding progeins can cause local uptake of Ga-67. Since these factors are present at sites of inflammation, they may contribute to the accumulation of gallium in inflammatory lesions.

Animals↗
PubMed1980

Capillary permeability in canine myocardium as determined by bolus injection, residue detection.

Capillary permeability of 51Cr-EDTA in the canine myocardium was determined by applying: (A) the single injection, external registration method, and (B) the local tissue clearance method, to the intact dog heart of open-chest anesthetized dogs. (A) 51Cr-EDTA was administered into the left anterior descending coronary artery as a bolus injection, and the response curve was recorded by external registration. The capillary diffusion capacity (the permeability-surface area product) for 51Cr-EDTA amounted to 32.5 ml/100 g x min at a capillary extraction of 0.40 and a plasma flow of 73.3 ml/100 g x min. The diffusional permeability coefficient of 51Cr-EDTA was calculated to 1.08 x 10(-5) cm/s, which indicates that the permeability of the capillaries in the myocardium for 51Cr-EDTA is similar to that of continuous capillaries in other tissues. (B) 51Cr-EDTA (3-100 microliters) was injected at a depth of 5 mm into the myocardium of the left ventricular free wall and the residue curve was recorded. The capillary extraction, as determined by the tissue clearance method, was calculated to values 6 times smaller than determined with the single injection, residue detection method. This unreasonably low extraction was probably due to methodological errors inherent to the tissue clearance technique.

Animals↗
PubMed1994

Simultaneous measurement of bidirectional capillary permeability, vascular volume, extracellular space, and rCBF in experimental gliomas and surrounding edema.

Measurements of bidirectional capillary permeability in the ASV tumor model revealed a heterogeneous distribution of transport rates for the small water-soluble molecules which are believed to be the driving force in perifocal edema formation. Mean K1 values were 8.1 +/- 5.5 microliters/g/min in whole tumor and 18.89 +/- 12.3 microliters/g/min in highly permeable areas. Tumor blood flow ranged between normal white matter and cortex, whereas the plasma vascular space in the tumors was increased as compared to the normal brain. The size of the extracellular space was depending on the regional capillary permeability, underlining the vasogenic nature of peritumoral edema which was capable of being studied using in vivo methods.

Animals↗
PubMed1996

Prostacyclin counteracts the increase in capillary permeability induced by tumour necrosis factor-alpha.

OBJECTIVE: To analyse how prostacyclin interferes with the short-term local circulatory effects of tumour necrosis factor-alpha (TNF alpha) in a skeletal muscle. DESIGN: An autoperfused sympathectomised cat gastrocnemius muscle enclosed in a plethysmograph. INTERVENTIONS: Arterial blood flow, total and segmental vascular resistances (large-bore arterial vessels, arterioles and veins), hydrostatic capillary pressure, tissue volume and capillary filtration coefficient were followed during local intra-arterial infusion of TNF alpha at various rates (2.5, 5.0 and 7.5 micrograms/kg per min) and during intra-arterial infusion of prostacyclin simultaneously with the highest dose of TNF alpha. The capillary filtration coefficient reflects the capillary surface for fluid exchange. RESULTS: Arterial infusion of TNFx had no influence on vascular resistance up to 5.0 micrograms/kg per min but induced vasodilation at 7.5 micrograms/kg per min. No effects on the recorded hydrostatic capillary pressure were observed. The capillary filtration coefficient and the capillary filtration increased with the infusion rate of TNF alpha, the former by 55%. Simultaneous arterial infusion of prostacyclin (350 ng/kg per min) caused further vasodilation and an increase in hydrostatic capillary pressure and completely restored the capillary filtration coefficient to control. The TNF alpha-induced filtration was partly restored. CONCLUSIONS: The local circulatory effect of TNF alpha is small apart from a graded increase in the capillary filtration coefficient, most likely reflecting an increase in the capillary permeability. The prostacyclin-induced decrease in capillary filtration coefficient most likely reflects a restoration of capillary permeability. The TNF alpha-induced transcapillary filtration is not fully reduced by prostacyclin due to a simultaneous increase in hydrostatic capillary pressure.

Animals↗
PubMed1995

Treatment with insulin-like growth factor I alters capillary permeability in skin and retina.

Treatment with insulin-like growth factor I (IGF-I) is accompanied by mild generalized and reversible edema. These changes may be due to increased capillary permeability. Therefore, we studied the effects of subcutaneous IGF-I treatment in healthy subjects on capillary permeability of the skin and the retina. Eight healthy subjects were treated with saline or recombinant human IGF-I (rhIGF-I) (10 micrograms.kg-1.h-1 s.c.) in a randomized crossover fashion. Transcapillary diffusion of sodium fluorescein (NaF) was quantitated by video densitometry in the skin in all subjects on the 4th treatment day. In seven subjects, plasma penetration of NaF at the blood-retinal barrier was investigated using vitreous fluorometry (VF) on days 3 and 5. Fluorescent light intensities of the skin and plasma penetration determined by VF were significantly higher during the IGF-I treatment as compared with those during the control situation. In conclusion, IGF-I treatment at the above dose is accompanied by increased transcapillary diffusion of NaF in skin and in retinal vessels.

Adult↗
PubMed1982

[An ultrastructural study of capillary permeability of rabbit ovarian follicles using horseradish peroxidase as a tracer (author's transl)].

In the previous study, using carbon tracer, we reported the ultrastructural evidences which suggested the increased capillary permeability of preovulatory rabbit ovarian follicles. In the present study, another tracer, horseradish peroxidase (HRP 50 A in diameter, mw. 40,000), being smaller than carbon particle, was used to examine the permeability of perifollicular capillaries. HRP left capillaries and appeared in the follicular cavity immediately after the injection into aorta, through all stages of follicular development. In the capillaries, the narrow interendothelial clefts (about 100-200 A in width) were observed through preovulatory stages. Fenestrations were noted at 3,4,6 hours after the hCG injection, and interendothelial gaps (about 1,000-10,000 A in width) were seen at 10, 12 hours. HRP passed through these structures and infiltrated the capillary basal lamina and the basal lamina of the follicle and went through the intercellular spaces between granulosa cells. Therefore, the increased permeability of perifollicular capillaries, just prior to ovulation, were not so obvious as when carbon particles were used. On the other hand, carbon particles, injected via marginal ear vein, were incorporated in the endothelial vesicles 15 min. after its administration and retained beneath the basal lamina outside the follicle within 60 min. These observations indicated that "blood follicle barrier" consisting of capillary endothelium, basal lamina, basal lamina of the follicle and granulosa layer played an inhibitory role to large molecules but not to small molecules.

Animals↗
PubMed1988

Some properties of a proteolytic enzyme from the venom of Agkistrodon caliginosus (kankoku-mamushi) which increases capillary permeability.

The molecular weight of the capillary permeability-increasing enzyme from the venom of A. caliginosus was estimated to be about 32,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This enzyme consists of a single polypeptide chain with an isoelectric point of pH 4.80. The enzyme is composed of 266 amino acid residues, based on a molecular weight of 32,000, and contained 11.4% carbohydrate. The enzyme more readily hydrolyzed arginine esters than lysine esters and did not hydrolyze tyrosine ester. Both the arginine ester hydrolytic and capillary permeability-increasing activities were inhibited by treatment with diisopropylfluorophosphate, indicating that the enzyme is an arginine esterase of the serine proteinase type. The substrate specificity of the enzyme toward synthetic chromogenic or fluorogenic substrates for mammalian serine proteinases and the pH and heat stabilities of the enzyme were also investigated.

Amino Acids↗
PubMed1988

Increase in pulmonary capillary permeability in dogs exposed to 100% O2.

Changes in pulmonary capillary filtration induced by hyperoxia were investigated in 15 dogs. After 12 h of normobaric hyperoxic exposure, animals were anesthetized and artificially ventilated with 100% O2. A pulmonary lymphatic vessel was cannulated, and lymph flow and protein content were measured together with pulmonary and systemic hemodynamics. An increase in pulmonary capillary filtration was found when compared with reference data (normoxic dogs in similar conditions) gathered from available literature: lymph flow increased from 21.8 +/- 13.4 to 125.2 +/- 131.6 microliter/min, and the lymph-to-plasma protein concentration ratio increased from 0.67 +/- 0.08 to 0.78 +/- 0.08. To characterize the mechanisms involved, left atrial pressure was increased in two stages (approximately 10 and approximately 25 mmHg). The results clearly indicated an increase in pulmonary capillary permeability as evidenced by a decrease of the minimal estimate of the protein reflection coefficient from 0.62 +/- 0.05 to 0.42 +/- 0.05.

Animals↗
PubMed1981

Effect of injected human chorionic gonadotrophin on capillary permeability, extracellular fluid volume and the flow of lymph and blood in the testes of rats.

The subcutaneous injection of human chorionic gonadotrophin (HCG) into adult male rats caused appreciable rises in capillary permeability and lymph flow in the testis, accompanied by smaller rises in the volume of extratubular, extracellular fluid. Most of these changes were already apparent 8 h after injection, but became progressively greater during the next 12 h. Testicular blood flow was unchanged at 12 h but increased slightly between 12 and 6 h after injection. The primary effect is probably the increase in capillary permeability. The timing of these changes suggests that HCG does not affect the capillaries directly, but it would seem that the changes are due to some substances secreted by the testis in response to the HCG. It is clear that these changes will have important influences both on the access to the testicular cells of peptide hormones in the blood and also on the passage into the venous blood of hormones secreted by the testis.

Animals↗
PubMed1991

Increased capillary permeability to albumin and diabetic neuropathy.

An increase in the capillary permeability to albumin (CPA) has been reported in diabetic patients. We observed this frequently with a non-invasive isotopic test derived from the Landis method, using 99mTc-albumin and measuring residual radioactivity externally after removal of forearm venous compression. Evidence of the independent effects of hypertension and microangiopathy on CPA has already been found. The present work was designed to investigate CPA using the same test on diabetic patients without retinopathy and clinical proteinuria. Some of these patients had objective clinical distal and symmetrical polyneuropathy. Neuropathy was clearly present in 10 of the 11 patients with an abnormal test unexplained by causes other than diabetes and in only one of the 17 patients with a normal test. The most frequent abnormality affected the late radioactivity disappearance curve, which probably reflects an impaired lymphatic wash-out of interstitial albumin. These results strongly suggest a link between peripheral neuropathy and diabetic functional microangiopathy. An elevated blood flow secondary to sympathetic nerve failure may induce an increase in CPA and a saturation of lymphatic pumping which could also be deficient due to impaired lymphatic innervation.

Adult↗
PubMedDate not supplied

Changes in capillary permeability in diabetic patients.

Microangiopathic disorders, characterized by capillary vasodilation and increases in capillary blood flow and permeability, are common in diabetes and can occur before the development of microangiopathic complications. In a study of 163 diabetic patients, capillary permeability, measured by albumin retention (AR), was increased in 39% of patients. AR was increased more frequently in women than in men, and in patients without microangiopathic complications than in patients with complications. Increased AR was significantly associated with insulin-dependent diabetes in male patients. Lymphatic function was abnormal in 72% of patients; this abnormality was often present before AR increased. The pathophysiology of microangiopathy is complex and involves metabolic, haemodynamic, neurological and hormonal factors. Improved control of glycaemia and blood pressure can reduce capillary permeability. In addition, studies with a flavonoid fraction and n-3 polyunsaturated fatty acids suggest that these agents may also be beneficial.

Capillary Permeability↗
PubMed1996

Evidence against an increase in capillary permeability in subjects exposed to high altitude.

A potential pathogenetic cofactor for the development of acute mountain sickness and high-altitude pulmonary edema is an increase in capillary permeability, which could occur as a result of an inflammatory reaction and/or free radical-mediated injury to the lung. We measured the systemic albumin escape by intravenously injecting 5 muCi of 125I-labeled albumin and the plasma concentrations of cytokines, F2-isoprostanes (products of lipid peroxidation), and acute-phase proteins in 24 subjects exposed to 4,559 m. Ten subjects developed acute mountain sickness, and four subjects developed high-altitude pulmonary edema. The transcapillary escape rate of albumin was 6.9 +/- 2.0%/h (SD) at low (550 m) and 6.3 +/- 1.9%/h at high (4,559 m) altitude (P = 0.23; n = 24). The subjects with high-altitude pulmonary edema had a modest but insignificant increase in the transcapillary escape rate of albumin (4.6 +/- 1.9%/h at low vs. 5.7 +/- 1.9%/h at high altitude; P = 0.42; n = 4). Plasma concentrations of fibrinogen, alpha 1-acid glycoprotein, C-reactive protein, and interleukin-6 were unchanged in the early phases and significantly increased by the end of the observation period in the subjects with high-altitude pulmonary edema, whereas tumor necrosis factor-alpha and F2-isoprostanes did not change at all. This suggests that the inflammatory reaction was rather a consequence than a causative factor of high-altitude pulmonary edema. In summary, these data argue against a dominant role for increased systemic capillary permeability in the development of acute mountain sickness and high-altitude pulmonary edema.

Acclimatization↗
PubMed2002

Endothelin A but not endothelin B receptor blockade reduces capillary permeability in severe experimental pancreatitis.

INTRODUCTION: Microcirculatory disorders, in particular increased capillary permeability (CapPerm), contribute to the multiple organ dysfunction syndrome in severe acute pancreatitis (AP). Endothelin receptor antagonists (ET-RA) have been shown to stabilize capillary leakage and improve organ function in AP. AIM: To find out which endothelin receptor subtype (ET-A or ET-B) mediates the changes in CapPerm. METHODOLOGY: Severe AP was induced in rats by intraductal bile salt infusion and i.v. cerulein. Animals were randomized to receive (1) saline; (2) selective ET-A-RA (LU-135252; 30 mg/kg); (3) selective ET-B-RA (A-192621); (4) nonselective ET-RA (LU-135252; 120 mg/kg); or (5) combined ET-A/B-RA (30 mg/kg LU-135252 + A-192621). Capillary blood flow (CBF) and CapPerm in the pancreas and colon and leukocyte rolling in mesenteric venules were determined. RESULTS: Selective ET-A-RA increased CBF and decreased CapPerm in the pancreas and colon by 90-147% and reduced leukocyte rolling in AP but had no effect in healthy controls. Selective ET-B-RA increased pancreatic CBF (2.3 +/- 0.03 versus 2.1 +/- 0.04 nL/min) and enhanced CapPerm in the pancreas and colon by 24-35% in healthy controls but had no effect in AP. Blockade of both receptors produced effects similar to but less pronounced than those of selective ET-A-RA. CONCLUSIONS: Blockade of ET-A and ET-B receptors has different effects on CapPerm in healthy animals and those with AP. This may explain the inconclusive results reported with nonselective ET-RA. In severe AP, blockade of ET-A but not ET-B receptors reduces CapPerm.

Acute Disease↗
PubMed1979

Studies on ocular blood flow and retinal capillary permeability to sodium in pigs.

A surgical technique was developed in pigs that permits access to the retinal venous plexus surrounding the optic nerve. The effect of surgery on ocular blood flow and capillary permeability was evaluated. Blood flow, determined by the labelled microsphere technique, did not differ significantly between operated and control eyes. Increased intraocular pressure in the operated eye reduced blood flow through the choroid and the anterior uvea in proportion to the reduction in perfusion pressure, while in the retina a smaller reduction in blood flow occurred indicating that autoregulatory mechanisms are involved in the control of retinal blood flow. The capillary permeability to sodium was studied by the single injection technique, using albumin as a reference substance. The fractional initial extractions from the choroidal and the retinal vessels were 0.77 and -0.001 respectively. The absence of a sodium extraction from the retinal vessel indicates that this part of the blood-retinal barrier was intact and that the blood drained by the retinal plexus is not mixed with blood from other sources.

Animals↗
PubMedDate not supplied

The effect of uridine and inosine on capillary permeability in the rat.

The effect of uridine and inosine on capillary permeability in the rat was investigated. Uridine produced a significant expansion of the albumin space which was accompanied by a significant increase in haematocrit indicating a leakage of water and proteins from the intra- to the extravascular compartment. This was attributed to a prominent constrictor effect of this substance on the post-capillary vessels. Inosine, on the contrary, produced an increase of the albumin space which was accompanied by a fall in haematocrit, indicating an expansion of the plasma volume. This was attributed to the vasodilator effect of inosine. It is suggested that these two substances may be involved in the control of the circulation.

Animals↗
PubMed2005

Superoxide dismutase mimetic preserves the glomerular capillary permeability barrier to protein.

Overproduction of superoxide (O2*) occurs in glomerular disease and may overwhelm the capacity of superoxide dismutase (SOD), thereby intensifying oxidant injury by O2* and related radical species that disrupt the glomerular capillary permeability barrier to protein. We examined the efficacy of the SOD mimetic tempol in preserving glomerular permeability to protein using 1) a rat model of glomerular immune injury induced by an antiglomerular basement membrane antibody (anti-GBM), and 2) isolated rat glomeruli in which injury was induced by the cytokine tumor necrosis factor-alpha (TNFalpha). To induce glomerular immune injury, rats received anti-GBM using a protocol that results in prominent infiltration of glomeruli by macrophages and in which macrophage-derived TNFalpha has been shown to mediate albuminuria. To increase glomerular capillary permeability to albumin (P(alb)) ex vivo, isolated glomeruli were incubated with TNFalpha at concentrations (0.5-4.0 microg/ml) known to stimulate O2* production. Increments in P(alb) were detected by measuring changes in glomerular volume in response to an applied oncotic gradient. Significant increases in the urine excretion of albumin and F(2alpha)-isoprostane were observed in rats with glomerular immune injury without a significant change in systolic blood pressure. Tempol treatment significantly reduced urine isoprostane and albumin excretion. In isolated glomeruli, TNFalpha increased P(alb) and tempol abrogated this effect, both in a dose-dependent manner. These observations indicate that SOD mimetics can preserve the glomerular permeability barrier to protein under conditions of oxidative stress from O2* production.

Animals↗