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At least 1,153 records · Page 64Linked to original sources
PubMed1998

Alveolo-capillary protein permeability and lung function in patients with late pulmonary complications after allogeneic bone marrow transplantation.

A prospective study was performed to identify markers predictive for the development of pulmonary complications in the early (<50 days) and late (>50 days) phase after bone marrow transplantation (BMT). The characterization of BMT patients with early or late pulmonary complications revealed clear-cut differences. Early and long term increase of alveolo-capillary protein permeability was associated with smoking and was found in 20 patients developing pulmonary complications within 50 days after BMT (group 1). The 22 patients who developed such complications thereafter (group 2) had more acute graft vs host disease than 66 patients who remained free of these complications for a minimum of 1 year. Concentrations of bronchoalveolar lavage (BAL) fluid albumin (alb) and serum beta2-microglobulin (S-beta2m) were determined 10 days before BMT, on days 1, 30, and 40 after BMT, whereas lung function tests were performed before BMT, after discharge from the hospital, and 6 months as well 1 year after BMT. Using cut-off values for BAL fluid alb (>2.3 mg/dl) and S-beta2m (>0.8 mg/liter) we could significantly discriminate 12 patients out of 19 group 1 patients (early pulmonary complications) as well as 9 out of 21 group 2 patients (late pulmonary complications) from 12 out of 64 group 3 patients (without such complications) 1 day after BMT. Our results demonstrate that early increased alveolo-capillary protein permeability defines a patient population at risk to develop pulmonary complications later than 50 days after BMT with up to 1 year significantly decreased lung volumes (FEV1, 73% predicted, VC, 85% predicted).

Adolescent↗
PubMed2004

The influence of oxidative stress on permeability of capillary vessels in the cheek pouch of hamsters with alloxan-induced diabetes.

BACKGROUND: The aim of the study was to assess the influence of oxidative stress on the increase of permeability of capillary vessels in animals with alloxan-induced diabetes. MATERIAL AND METHODS: The studies were performed in microcirculation system of hamster cheek pouch. After the blockade of histamine receptors and administration of diamine oxidase (DAO) and histamine into circulation fluorescein angiography was done. In addition, the influence of superoxide dismutase, aminoguanidine (DAO inhibitor) and trascolan (protease inhibitor) on vascular permeability caused by superoxide radical generation in DAO/histamine system was assessed. RESULTS: The number of extravasal leakages in the group receiving HA and DAO was significantly higher (p < 0.001) than in the groups receiving potential vascular "sealers", e.g. SOD, aminoguanidine or trascolan. In the group receiving aminoguanidine the number of leakages was significantly lower (p < 0.05) compared to the group receiving SOD or trascolan. CONCLUSIONS: The protective effect of aminoguanidine, superoxide dismutase or trascolan decreasing the vascular permeability, suggests that the increased vascular permeability is a result of superoxide radical generation by diamine oxidase.

Amine Oxidase (Copper-Containing)↗
PubMed1993

Use of adrenocorticotrophic hormone analog to minimize brain injury.

STUDY OBJECTIVES: To investigate the effects of a vasoactive analog of adrenocorticotrophic hormone (GMM2) on time-dependent disturbances in regional cerebral blood flow, permeability-capillary surface area products, and intracranial pressure in a rat model of moderate concussion/brain injury. SETTING AND DESIGN: Regional permeability-capillary surface area products and cerebral blood flow were measured at two hours after trauma. Intracranial pressure was monitored for 120 hours after trauma. SUBJECTS: Male Wistar rats (330 to 430 g) (regional cerebral blood flow studies, n = 35; permeability-capillary surface area product studies, n = 36; intracranial pressure studies, n = 32). INTERVENTIONS: Post-traumatic subcutaneous administration of nanomolar concentrations of GMM2 (31 nmol per rat). MEASUREMENTS AND MAIN RESULTS: Untreated trauma acutely increased average brain permeability-capillary surface area products for sucrose and decreased average brain cerebral blood flow. Moreover, it produced marked and prolonged increases in intracranial pressure. Post-traumatic subcutaneous administration of nanomolar concentrations of GMM2 effectively reduced the early hypoperfusion, blood-brain barrier leakiness, and pathologic elevation of intracranial pressure. CONCLUSION: Post-traumatic administration of GMM2, in nanomolar amounts, can prevent or reverse significantly the serious cerebrovascular sequelae of moderate head injury in this animal model. In view of its potency, low toxicity, and other neuroprotective properties, in both rats and human beings, these data suggest that GMM2 may have considerable clinical benefits in the treatment of central nervous system trauma.

Adrenocorticotropic Hormone↗
PubMed1999

Evaluation of the alveolar-capillary membrane permeability using 99mTc-HMPAO aerosols in severe diffuse interstitial fibrosis.

Local information on permeability of the alveolar-capillary barrier (PACB) can be ascertained by parametric images, after inhalation of radioarosols and computer processing. Our aim is to compare the results of 99mTc-HMPAO aerosols on PACB studies with those of 99mTc-DTPA aerosols, a standard technique. We compared the two techniques in separate samples: normal controls and patients with severe lung interstitial pathologies. Perfusion studies using 99mTc-MAA have also been performed in all patients. The aerosols were produced using ultrasound and lowered surface tension solution of 99mTc-HMPAO and 99mTc-DTPA. The time-activity curves (TACs) for every pixel on the lung area were used to calculate the half-disappearance times (T1/2). Parametric images were then generated with those times. The comparison of the results obtained with 99mTc-HMPAO and 99mTc-DTPA aerosols suggests that the first ones are more specific for local alterations of the lung epithelial transport in the pathologies studied. This method distinguishes between permeability deficiency due to local perfusion decrease and ACB deterioration.

Aerosols↗
PubMed1997

Antiinflammatory activities of procyanidin-containing extracts from Pinus pinaster Ait. after oral and cutaneous application.

Orally in liquid diet administered procyanidin-containing extracts from Pinus pinaster Ait. decreased the croton oil-induced ear edema in mice or the compound 48/80-induced hind paw edema in rats to a statistically significant extent. Most effective were the extracts containing mainly oligomeric procyanidins with chain lengths greater then 4 units (extracts A or B). Further, the different extracts incorporated in various concentrations (1.0, 3.0 or 0.1%) in 5% hydroxyethylcellulose gel and applied topically on the shaved back of rats, inhibited significantly the ultraviolet radiation-induced increased capillary permeability. In these experiments, normalisation of capillary permeability was not correlated with the content of the extracts on higher oligomeric procyanidins.

Administration, Oral↗
PubMed1994

Acute and chronic diuretic treatment selectively affects vascular permeability in the unanesthetized normal rat.

Diuretics are widely used antihypertensive agents, and although their renal actions have been well characterized, the extent of their vascular effects remains to be defined. Because hypertension is associated with numerous vascular complications whose incidences are not always lowered once blood pressure is regulated, this study was undertaken to evaluate the effects of five selected diuretics on capillary permeability to see if they could contribute in some way to these vascular abnormalities. Extravasation of Evans blue dye (EB: 20 mg/kg) injected in the caudal vein of male Wistar rats was used to assess capillary permeability to albumin. Indapamide (0.04 mg/kg), cicletanine (2.0 mg/kg), amiloride (0.3 mg/kg), hydrochlorothiazide (0.5 mg/kg) and furosemide (0.5 mg/kg) were administered by acute i.v. injection or by 10-day "chronic" gavage. EB extravasation was increased in the upper bronchi, lung parenchyma and kidney after acute administration of indapamide (54, 41 and 31%, respectively) and hydrochlorothiazide (45, 41 and 19%, respectively), and increased in all tissues but the duodenum (upper bronchi, lung parenchyma, heart, liver, kidney and muscle; 57-118%) after furosemide. In contrast, capillary permeability was reduced after acute cicletanine in the heart (31%), duodenum (49%) and muscle (58%) and after amiloride in the heart (25%) and muscle (63%). Pretreatment with indomethacin abolished most changes in EB extravasation induced by acute injection of the diuretics. After 10-day gavage, however, changes in capillary permeability were null after amiloride or hydrochlorothiazide treatment, attenuated after cicletanine or furosemide or even reversed after indapamide. Arterial pressure was not affected by diuretic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Compounds that increase cAMP prevent ischemia-reperfusion pulmonary capillary injury.

This study evaluated the physiological effects of compounds that increase adenosine 3',5'-cyclic monophosphate (cAMP) on changes in pulmonary capillary permeability and vascular resistance induced by ischemia-reperfusion (I-R) in isolated blood-perfused rabbit lungs. cAMP was elevated by 1) beta-adrenergic stimulation with isoproterenol (ISO, 10(-5) M), 2) post-beta-receptor stimulation of adenylate cyclase with forskolin (FSK, 10(-5) M), 3) and dibutyryl cAMP (DBcAMP, 1 mM), a cAMP analogue. Vascular permeability was assessed by determining the capillary filtration coefficient (Kf,c), and capillary pressure was measured using the double occlusion technique. The total, arterial, and venous vascular resistances were calculated from measured pulmonary arterial, venous, and capillary pressures and blood flow. Reperfusion after 2 h of ischemia significantly (P less than 0.05) increased Kf,c (from 0.115 +/- 0.028 to 0.224 +/- 0.040 ml.min-1.cmH2O-1.100 g-1). These I-R-induced changes in capillary permeability were prevented when ISO, FSK, or DBcAMP was added to the perfusate at reperfusion (0.110 +/- 0.022 and 0.103 +/- 0.021, 0.123 +/- 0.029 and 0.164 +/- 0.024, and 0.153 +/- 0.030 and 0.170 +/- 0.027 ml.min-1.cmH2O-1.100 g-1, respectively). I-R significantly increased total, arterial, and venous vascular resistances. These increases in vascular resistance were also blocked by ISO, FSK, and DBcAMP. These data suggest that beta-adrenergic stimulation, post-beta-receptor activation of adenylate cyclase, and DBcAMP prevent the changes in pulmonary vascular permeability and vascular resistances caused by I-R in isolated rabbit lungs through a mechanism involving an increase in intracellular levels of cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1997

Quantitative magnetic resonance imaging of capillary water permeability and regional blood volume with an intravascular MR contrast agent.

A novel method is presented to simultaneously measure the permeability surface area product of water (PS), also known as capillary diffusion capacity, and the regional blood volume (RBV). It is based on magnetic resonance imaging of the longitudinal relaxation times of tissue and blood at different concentrations of an intravascular MR contrast agent. PS and RBV were measured in vivo in different regions of the brain and the skeletal muscle of the rat. The average PS values (n = 5) obtained in cerebral cortex, corpus callosum, hippocampus, thalamus, jaw muscle, and tongue muscle were 3.31 +/- 0.20, 1.81 +/- 0.25, 3.37 +/- 0.36, 3.68 +/- 0.44, 10.6 +/- 1.1, and 14.1 +/- 2.51 ml x min(-1) x g(-1), respectively. The corresponding average RBV values were 1.63 +/- 0.18, 1.22 +/- 0.25, 3.30 +/- 0.37, 3.03 +/- 0.36, 1.66 +/- 0.30, and 1.38 +/- 0.33 ml x 100 g(-1). These results are in good agreement with previously reported literature values obtained by means of autoradiography.

Animals↗
PubMed1986

Phlogistic activity of leukotriene D4 in the mouse.

An investigation of the phlogistic activity of LTD4 in the mouse was accomplished by examination of its ability to cause increased capillary permeability and edema formation following subcutaneous administration. It was observed that nanogram quantities of LTD4 caused edema and increased capillary permeability in a dose-related manner. The increase in capillary permeability was not inhibited by pretreatment with indomethacin and thus was unrelated to the production of cyclo-oxygenase products. These data suggest that LTD4 can mediate the edematous phase of the inflammatory response in the mouse and illustrate the sensitivity of this species to LTD4.

Animals↗
PubMed1988

The use of perfluorochemical emulsion in the study of pulmonary microvascular permeability.

The perfluorochemical exchange transfused rat was used to examine whether the interaction of plasma proteins with the luminal surface of endothelial cells effects the permeability of pulmonary capillaries. Ultrastructural immunocytochemical techniques were used to localize albumin and IgG. The results indicated that the presence of plasma proteins localized solely within the glycocalyx was sufficient to render the underlying pulmonary capillary endothelium as impermeable to intravenously injected native ferritin (pI 4.7) as that of nonexchange transfused control rats. In further experiments it was observed that the removal of circulating plasma proteins by exchange transfusion resulted in the unmasking of anionic sites on the glycocalyx. This was determined by morphometry by counting the number of intravenously injected cationized ferritin particles (pI 8.5) bound to the luminal surface of the endothelium. There was no statistically significant difference in the amount of binding to the thick and thin sides of the capillaries. These observations support the fiber matrix model of capillary permeability as formulated by Curry and Michel.

Animals↗
PubMed1994

Effects of graded thermal injury on microvascular permeability at the site of injury.

To define whether capillary permeability traits at the site of a burn differ according to injury severity, a canine hind leg lymphatic was cannulated to measure macromolecular permeability in response to three different scalding solutions. Leg venous pressure was raised to approximately 40 mm Hg and maintained until a minimal lymph-to-plasma total protein ratio (CL/CP)min and steady-state lymph flow (QL; microliter/min/100 g) was attained. The protein reflection coefficient (1-CL/CP), fluid filtration coefficient (Kf; microliter/min/mm Hg/100 g), and QL were determined before and for 6 hr after a 5-sec hind paw immersion in either 100 degrees C (n = 7), 80 degrees C (n = 7), or 70 degrees C (n = 7) water. A group of five animals served as controls. In the absence of any systemic hemodynamic alterations, the 100 and 80 degrees C scald groups experienced significant (P < 0.05, ANOVA) increases in QL, CL/CP, and Kf as compared to respective preburn values and time-matched unburned control values. Most monitored parameters were significantly higher following 100 degrees C injury vs 80 degrees C injury. Parameters in the 70 degrees C group did change after scald, but were not significantly different from preburn values or from the control group. Alterations in capillary permeability to protein and fluid flux measured at the burn site are graded, not all or none phenomena, being dependent upon the severity of injury.

Analysis of Variance↗
PubMed1995

Disorders of body fluid balance: a new look into the mechanisms of disease.

OBJECTIVE: To review the mechanisms of disease on the basis of dysfunction in body fluid distribution secondary to abnormalities in capillary permeability and plasma membrane transport disorders, leading to quantitative and qualitative alterations of the interstitial space, a mainly strategic compartment positioned between the microcirculation and cell mass. DATA SOURCES: The recent literature on the mechanisms involved in the control of body fluid balance, with special reference to microcirculation and interstitial compartment physiology, as well as published and unpublished original data from the authors laboratory. DATA EXTRACTION AND SYNTHESIS: To illustrate the importance of capillary permeability dysfunction in the development of disease, animal (rat and dog) models of chronic renal failure, acute diuretic-induced fluid depletion, diabetes mellitus, arterial hypertension and ischemia-reperfusion of the kidney were used in an attempt to show that in all these experimental models, basic capillary permeability dysfunction (measured by the extravasation of Evans blue, a marker of albumin leakage) develops in specific microcirculation beds. As a consequence, tissue edema (interstitial and/or cellular) develops and likely impairs the traffic of nutrients and waste products to and from the cellular mass, and/or challenges the microcirculation, leading to organ damage. Kidney dysfunction is measured by conventional clearance methods (renal hemodynamics and tubular function). In some models, the eventual mediators of vascular abnormality are examined by use of pharmacological tools. CONCLUSIONS: The critical role of microcirculation dysfunctions, in particular capillary permeability, resulting in interstitial compositional changes is presented as the basis of disease. The apparent specificity of target organ damage may represent the nonspecific result of physicochemical alteration in the strategic interstitial fluid compartment.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1984

Intratesticular factors controlling testicular function.

Although the testis is under overall control by pituitary gonadotropins, intratesticular control mechanisms are important 1) because of the unique structural organization of the testis, and 2) because of the organization and local requirements of spermatogenesis. The avascular nature of the seminiferous tubules, which comprise 90% of testicular mass in most mammals, means that their exceptionally high energy and nutritional demand has to be met by local transport in testicular interstitial fluid (IF). The rate of formation of IF is determined by capillary permeability and local control of this process is thus a prerequisite for ensuring full nutritional and hormonal support for spermatogenesis. The latter is organized into specific stages arranged in a cycle, each stage having different requirements which only local control mechanisms can ensure. In the rat, Stage VII of the spermatogenic cycle has an absolute requirement for high levels of testosterone and maintenance of such levels in the testicular IF surrounding the tubules thus constitutes a crucially important function requiring local control. Because in this situation, testosterone works via the Sertoli cell and because the testosterone is produced locally by the Leydig cells in response to luteinizing hormone (LH), it is suggested that local control of intratesticular levels of testosterone is likely to be effected by a factor (or factors) produced by the Sertoli cell which acts on the Leydig cell, and which interacts with LH to modulate the levels of testosterone in testicular IF. The possibility that "testicular luteinizing hormone releasing hormone (LHRH)" may fulfill this role is examined in detail by investigating the local effects of an LHRH agonist (LHRH-A) on testicular capillary permeability and the IF levels of testosterone in normal intact adult rats. The results show that LHRH-A has dose-dependent effects on capillary permeability and the IF levels of testosterone and that these effects are modulated according to the ambient level of LH. Alteration of the IF levels of testosterone by LHRH-A is shown to be biologically effective and to be mediated partly by direct effects on Leydig cell steroidogenesis and partly by the control of capillary permeability. The physiological implications and operation of this local mechanism are discussed.

Animals↗
PubMed2002

Improved accuracy of human cerebral blood perfusion measurements using arterial spin labeling: accounting for capillary water permeability.

A two-compartment exchange model for perfusion quantification using arterial spin labeling (ASL) is presented, which corrects for the assumption that the capillary wall has infinite permeability to water. The model incorporates an extravascular and a blood compartment with the permeability surface area product (PS) of the capillary wall characterizing the passage of water between the compartments. The new model predicts that labeled spins spend longer in the blood compartment before exchange. This makes an accurate blood T(1) measurement crucial for perfusion quantification; conversely, the tissue T(1) measurement is less important and may be unnecessary for pulsed ASL experiments. The model gives up to 62% reduction in perfusion estimate for human imaging at 1.5T compared to the single compartment model. For typical human perfusion rates at 1.5T it can be assumed that the venous outflow signal is negligible. This simplifies the solution, introducing only one more parameter than the single compartment model, PS/v(bw), where v(bw) is the fractional blood water volume per unit volume of tissue. The simplified model produces an improved fit to continuous ASL data collected at varying delay time. The fitting yields reasonable values for perfusion and PS/v(bw).

Capillary Permeability↗
PubMed2001

Evaluation of treatment of diabetic microangiopathy with total triterpenic fraction of Centella asiatica: a clinical prospective randomized trial with a microcirculatory model.

Fifty patients with diabetic microangiopathy were studied by laser Doppler flowmetry (measuring skin blood flow at rest) (RF) and the venoarteriolar response (VAR), by transcutaneous PO2 and PCO2 measurements, and by capillary permeability evaluation (rate of ankle swelling [RAS]). Thirty of these patients were treated for 6 months with total triterpenic fraction of Centella asiatica (TTFCA) (60 mg twice daily), a drug active on microcirculation and capillary permeability. A control group of ten patients was treated with placebo and another group of ten patients was left without treatment thus acting as a second control group. After six months there were no significant changes in the two control groups. There was a significant improvement of microcirculatory parameter in patients treated with TTFCA. RF (abnormally increased at the beginning of the treatment) decreased, and the VAR (impaired at the beginning of the study) improved. PO2 increased and PCO2 decreased the abnormally increased capillary permeability was also improved (decreased). According to these data, TTFCA is useful in diabetic microangiopathy by improving microcirculation and decreasing capillary permeability. Also TTFCA protects against the deterioration of microcirculation due to diabetic microangiopathy.

Adult↗