Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Capillary Permeability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed1978

Hypovolaemic shock with oedema due to increased capillary permeability.

A case of severe hypovolaemic shock related to idiopathic oedema was observed in a 37 year old woman. Large plasma volume expansion (nearly 12 1 over 9 hours) did not change the clinical status. Haemodynamic studies showed low cardiac index (1.1 1/min/m2), decreased left ventricular stroke work index (6.7 gm/m2), and high systemic arterial resistance (52 mmHg/1/min/m2). Dopamine infusion improved the haemodynamic condition which returned to normal 30 hours after the beginning of shock. After recovery, capillary permeability measured by a modification of Landis' method was markedly increased. A study of albumin metabolism showed a normal intravascular pool and a rapid exchange compartment with a twofold increase in slow exchange compartment. Hormonal levels and complement fractions were within normal limits. Serum protein immuno-electrophoresis showed an abnormal IgG. These results clearly demonstrate that hypovolaemia is related to increased capillary permeability and leakage of albumin out of the vascular space. When large infusions fail, inotropic agents, especially Dopamine, should be used in such cases.

Adult↗
PubMed1981

Regional blood flow and capillary permeability in the ethylnitrosourea-induced rat glioma.

Regional cerebral blood flow and capillary permeability of rat brains bearing ethylnitrosourea-induced gliomas of various size were investigated with 14C-antipyrine autoradiography and Evans blue staining. In the small tumors (less than 2 mm in diameter), blood flow was uniformly reduced when compared to the adjacent brain. Even in tiny tumors (0.3 to 0.4 mm in diameter), reduction in blood flow was evident. In the medium (2 to 4 mm in diameter) and large (greater than 4 mm in diameter) tumors, the blood flow increased or decreased depending on the part of the tumor examined. The necrotic center and peripheral edge had low blood flows, whereas the viable portion adjacent to the necrotic center had high blood flows. Blood flow in the brain tissue adjacent to medium and large tumors was lower than control brain tissue, probably due to local edema. Leakage of intravenous Evans blue in the tissue was only evident in the large tumors with central necrosis. The present findings suggest that neovascularization of the tumor may occur when the tumor reaches a certain size, and leaky new vessels may be the cause of brain edema associated with tumor.

Animals↗
PubMed1998

Reduction of capillary permeability in the fructose-induced hypertensive rat.

Impaired insulin transcapillary transport and the subsequent decrease in insulin delivery to target organs have been suggested to play a role in insulin resistance. These defects were studied in fructose-fed rats, an animal model with insulin resistance. For this study, male Sprague-Dawley rats were fed with either a 60% fructose enriched (F) or a standard chow diet (N) for a total of 2, 4, or 8 weeks. Capillary permeability to albumin was assessed at the end of each dietary period by quantifying the extravasation of albumin-bound Evans blue (EB) dye in different organs. Unanesthetized animals were injected with Evans blue dye (20 mg/kg) in the caudal vein 10 min before being killed and EB dye was extracted by formamide from selected organs collected after exsanguination. As expected, rats had an increase in blood pressure upon feeding with fructose at 4 and 8 weeks (F, 149 +/- 3 mm Hg; N, 139 +/- 3 mm Hg; P < .05). Using this technique, we showed a 56% and a 51% reduction in capillary permeability in skeletal muscles at 4 and 8 weeks of fructose feeding, respectively (4 weeks: N, 44.5 +/- 5.0 microg/g of dry tissue; F, 19.8 +/- 4.2 microg/g of dry tissue; P < .01 and 8 weeks: N, 23.3 +/- 3.7 microg/g of dry tissue; F, 11.3 +/- 4.0 microg/g of dry tissue; P < .05). Similar changes were observed at 4 weeks in the thoracic aorta (N, 82.8 +/- 8.8 microg/g of dry tissue; F, 53.0 +/- 5.1 microg/g of dry tissue; P < .02) and skin (N, 36.0 +/- 5.3 microg of dry tissue; F, 15.0 +/- 2.3 microg/g of dry tissue; P < .02) and at 8 weeks in the liver (N, 107.5 +/- 4.3 microg/g of dry tissue; F, 80.9 +/- 3.2 microg/g of dry tissue; P < .01). In conclusion, fructose feeding is accompanied by a significant and selective reduction of Evans blue leakage primarily in skeletal muscle and liver, and transiently in the skin and aorta, consistent with a role for decreased tissue insulin delivery in insulin resistance.

Animals↗
PubMed1989

Capillary permeability induced by intravenous neurokinins. Receptor characterization and mechanism of action.

The effects on plasma extravasation of three increasing doses from 6.5 pmol to 650 nmol/kg of substance P (SP), SP fragments, neurokinin A (NKA), neurokinin B (NKB) and selective agonists for neurokinin receptors were assessed in three cutaneous tissues (skin of hind paws, dorsal skin and ears) by intravenous (i.v.) administration in the pentobarbitone anaesthetized rat. Dose-dependent increases in plasma extravasation were observed with the following rank orders of potency (SP greater than NKA greater than NKB) for neurokinins and (SP greater than [p-Glu6]SP(6-11) greater than SP(4-11) greater than [p-Glu5]SP(5-11) greater than SP(7-11] for C-terminal SP fragments. The metabolically stable SP analogue [p-Glu5, MePhe8, Sar9]SP(5-11) was slightly more potent than [p-Glu5]SP(5-11). The N-terminal fragments SP(1-4), SP(1-7) and SP(1-9) were inactive up to 650 nmol/kg. The NK-1 receptor selective agonists [Sar9, Met(O2)11]SP and [beta-Ala4, Sar9, Met (O2)11]SP(4-11) were more potent than the NK-2 [( Nle10]NKA(4-10] and NK-3 [( MePhe7]NKB and [beta-Asp4, MePhe7]NKB(4-10] receptor selective agonists. Plasma extravasation induced by SP (6.5 nmol/kg) was unchanged in the presence of atropine, methysergide, diphenhydramine or during the i.v. and intra-arterial (i.a.) infusion of D-Arg0[Hyp3.D-Phe7]BK, an antagonist of bradykinin. Plasma extravasation induced by SP and [Sar9, Met(O2)11]SP was significantly reduced by indomethacin while that induced by NKA, NKB, [beta-Ala4, Sar9, Met(O2)11]SP(4-11), SP(4-11) and [p-Glu6]SP(6-11) was unaffected by the cyclooxygenase inhibitor. Compound 48/80 (0.75 mg/kg), histamine (10 mg/kg) and 5-HT (10 mg/kg) caused an increase in plasma extravasation, only the effect of compound 48/80 was abolished by indomethacin. Pretreatment with compound 48/80 prevented its own action on plasma extravasation and significantly reduced that induced by 6.5 nmol/kg of SP. These results rule out the involvement of acetylcholine (muscarinic receptors), 5-HT (5-HT1 and 5-HT2 receptors), histamine (H1 receptors) and kinins (B2 receptors) in the response to SP and indicate that the two positively charged amino acids (Arg, Lys) at the N-terminal end of the SP molecule are essential to trigger the release of prostaglandins from mast cells. This mechanism is responsible for the indirect effect of SP and related peptides on capillary permeability and does not appear to be mediated by a selective SP receptor. In addition, neurokinins may increase capillary permeability by direct activation of a NK-1 receptor type on the vascular endothelium.

Animals↗
PubMed1991

Capillary permeability and basolateral endocytic pathway of the epithelium in the mouse endolymphatic sac in vivo.

The capillary permeability and the basolateral endocytic pathway of the mouse endolymphatic sac (ES) epithelium were examined in vivo using intravenous injection of horseradish peroxidase (HRP). The capillaries of the ES were classified as either fenestrated or non-fenestrated. Because dense reaction products were observed soon after injection of HRP in macrophages near both types of capillaries, they were both considered to be permeable to macromolecules. In non-fenestrated capillaries, the basement membrane and small vesicles of the endothelium of the ES were stained with reaction product. These non-fenestrated capillaries were considered to be of muscle type. After 15 min, ES epithelial cells absorbed HRP basolaterally, and the multivesicular bodies and lysosomes of epithelial cells were stained with reaction product. The process of basolateral absorption in the ES epithelium was similar to that in the intestinal epithelium. Our results provide further evidence that the ES is a metabolically active organ which plays an important role in fluid transport in the inner ear.

Absorption↗
PubMed1980

Estimation of capillary permeability of inulin, sucrose and mannitol in rat brain cortex.

The present study analyzed the brain uptake of the differently sized hydrophilic molecules 14C-inulin, 14C-sucrose and 14C-mannitol. constant tracer concentrations were maintained in blood plasma after renal ligation. Accumulation of the indicators was measured in brain cortex during the approach to steady-state. At the conclusion of infusion periods of 5, 10, 15, 30 and 60 min, samples of cerebral cortex were analyzed for radioactivity. Fractions attributable to blood in the tissue were subtracted and time-dependent apparent distribution volumes of the indicators in the tissue were estimated. The brain level did not rise to more than 1--2% of that in the plasma for inulin and sucrose and to 6--7% for mannitol. The explanation for this could be a combination of restricted penetration from blood into brain and a sink effect of cerebrospinal fluid (csf). to determine the removal of the indicators into csf, ventriculo-cisternal perfusion was performed during the period of tracer uptake in the the tissue; the rate of passage of the indicators into perfusion fluid was found to be negligible in comparison to the rates of uptake in the tissue. As diffusion in the extracellular space could limit uptake rates from blood to brain, estimates of diffusion limited half-times were also made. Calculations showed that the major hindrance to indicator uptake in the tissue is located in the wall of the brain capillaries; thus the uptake data permit calculation of brain capillary permeability. The half-times for the distribution of the indicators in their equilibrated tissue distribution spaces were used to estimate brain capillary permeability. By comparison with the aqueous diffusion coefficients of the indicators it is concluded that the substances in the molecular weight range of 182 to 5 500 daltons are subjected to restricted diffusion during the passage of the blood-brain barrier and that in addition non-discriminative transendothelial pathways are available.

Animals↗
PubMed1979

The investigation of capillary permeability in single vessels.

Measurements of filtration coefficients (Lp) and osmotic reflexion coefficients (sigma) of single capillaries in the frog mesentery suggest that fluid flows through the walls of these vessels in two types of channel. One channel type (representing about 10% of Lp) appears to be exclusively available for water whereas the other channels appear available for both water and hydrophilic solutes though they severely restrict the passage of albumin (sigma = 0.81). The effects of proteins in the perfusate upon Lp and studies on the passage of ferritin into the surface vesicles of the endothelial cells, suggest that an important component of capillary permeability may reside in an endocapillary layer.

Animals↗
PubMed1989

[Effect of histamine on the capillary permeability of the nasal mucosa in normal rats].

The effect of histamine on the capillary permeability of the nasal mucosa was studied quantitatively in normal rats using the Evans blue technique. The content of Evans blue in terms of ng per mg of nasal mucosa was significantly (P less than 0.001) higher in histamine group than that in control group, and reached peak value five minutes after injection of histamine at the concentration of 10(-8) mol/L. It is thought that this preliminary result might be useful in selecting optimal concentration of the challenge agent and the optimal time to evaluate the reaction.

Animals↗
PubMed1999

Low-dose prostacyclin is superior to terbutaline and aminophylline in reducing capillary permeability in cat skeletal muscle in vivo.

OBJECTIVE: To analyze and compare the capillary permeability-reducing effects of prostacyclin, terbutaline, and aminophylline. DESIGN: A prospective, experimental study. SETTING: A university laboratory. SUBJECTS: Fourteen adult, anesthetized cats. INTERVENTIONS: The study was performed on an autoperfused calf muscle preparation enclosed in a plethysmograph, with continuous recordings of tissue volume, arterial and venous blood pressures, and blood flow. The capillary filtration coefficient was used as a measure of capillary hydraulic permeability, and measured at different doses of intravenous infusions of prostacyclin, terbutaline, and aminophylline. These analyses were made from normal and from raised permeability levels, the latter by prior and simultaneous infusion of tumor necrosis factor-a (TNF-a) or histamine. All three of the drugs analyzed were given at low doses, without vasodilator effect, and at doses with a clear vasodilator effect. MAIN RESULTS: Prostacyclin infusion reduced capillary permeability to a value of about 25% below the initial control value, and this level was reached both from normal and increased permeability levels. The maximal reduction level was obtained at a low nonvasodilator dose of 2 ng/kg/min. Terbutaline and aminophylline had no significant effect on capillary filtration coefficient when tested from the initial control permeability level. From a TNF-alpha-raised permeability level (about 50% above control) and from a histamine-raised permeability level (about 60% above control), both drugs induced small reductions in the capillary filtration coefficient. CONCLUSION: Low-dose prostacyclin effectively reduces hydraulic capillary permeability in cat skeletal muscle and is superior to terbutaline and aminophylline.

Adrenergic beta-Agonists↗
PubMed1987

Isotopic test of capillary permeability to albumin in diabetic patients: effects of hypertension, microangiopathy, and duration of diabetes.

Capillary permeability to albumin (CPA) was studied by performing an isotopic noninvasive test with venous compression on 87 nonselected diabetics with no edema, no cardiac failure, and no peripheral vascular disease. Excessive albumin retention (AR greater than or equal to 8%) ten minutes after removal of the compression was found in 27 patients (31%). The radioactivity disappearance curve was then analyzed using the Fast Fourier Transform (FFT). An abnormal isotopic CPA test was thus found in at least 45 out of the 87 patients. The prevalence of an abnormal test was not different in type 1 and type 2 diabetics. We studied the independent effects of hypertension, presence of specific clinical signs of microangiopathy (retinopathy and/or significant proteinuria), and duration of diabetes. Among diabetics free of specific clinical signs of microangiopathy, the prevalence of an AR greater than or equal to 8% was significantly higher in those with hypertension (11/19) than in those with normal blood pressure (2/28) and in nondiabetic hypertensive patients (0/16). Among normotensive diabetics, the prevalence of an abnormal test was higher, but not significantly, in patients with specific clinical signs of microangiopathy (8/11) than in those free of them (7/18). Seven normotensive diabetics without specific clinical signs of microangiopathy had an abnormal test; five of them had had diabetes for more than five years. The prevalence of diabetes of more than five years duration was significantly higher in patients with an abnormal test (35/45) than in normotensive diabetics free of specific clinical signs of microangiopathy with a normal test (4/11).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗