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PubMed1976

Digital vascular responses and permeability in equine alimentary laminitis.

Digital vascular pressures, blood flow, and vascular resistances were measured in 11 control ponies and in 8 animals (7 ponies and 1 horse) affected with laminitis created by feeding a high starch ration. Animals with laminitis had increased digital blood flow, increased arterial, small vein, and large vein pressures, and decreased vascular resistances. Comparison of digital lymph flow rates and protein concentrations in animals with laminitis and control animals revealed no differences. Digital vascular responses of the 2 groups to acetylcholine, epinephrine, histamine, or serotonin also did not differ. Thus, the increased digital blood flow observed in animals with laminitis could not be attributed to altered responsivenss to the previously mentioned vasoactive agents. The studies also provided no evidence for increased capillary permeability in digits of animals affected with laminitis.

Acetylcholine↗
PubMedDate not supplied

Increased cerebrospinal fluid protein and lipid peroxidation products in patients with cerebral malaria.

Membrane lipid peroxidation by reactive oxygen species leading to increased capillary permeability is considered an important event in the pathogenesis of severe malaria. A significant decrease in plasma albumin and increases in cerebrospinal fluid (CSF) protein and malondialdehyde (MDA) were observed in 73 patients with cerebral malaria, compared to values in 23 control patients. The greatest effect was noticed in the most severely ill patients. The ratio of CSF protein to plasma albumin was increased in the patients compared to the controls, and in fatal cases of cerebral malaria compared to non-fatal cases. Brain necropsies showed oedema, fibrin deposits and mononuclear cell infiltration. It is proposed that cerebral oedema due to enhanced permeability of vascular endothelium induced by increased lipid peroxidation plays a crucial role in the causation of cerebral malaria.

Capillary Permeability↗
PubMed1996

Neutrophil enhancement of reperfusion-induced capillary fluid filtration associated with hypercholesterolemia.

Fluid filtration rate (Jv/S) from individual mesenteric capillaries in normocholesterolemic and hypercholesterolemic rats was measured before and after 30 min each of ischemia and reperfusion (I/R). The median I/R-induced increase in Jv/S (I/R vs. baseline) was 44% in normocholesterolemic rats (n = 11) and 97% in hypercholesterolemic rats (n = 11). A positive correlation slope of 0.20% per mg/dl resulted when the percent Jv/S increase vs. plasma cholesterol concentration (P = 0.02) was plotted, demonstrating that hypercholesterolemia enhances the capillary response to I/R. Because microvascular pressure did not change significantly after I/R in either group of rats, the increments in Jv/S likely reflect increased capillary permeability. In hypercholesterolemic rats rendered neutropenic with antineutrophil serum, I/R did not elicit a significant increase in Jv/S, suggesting that activated neutrophils mediate the exaggerated endothelial barrier dysfunction associated with hypercholesterolemia.

Animals↗
PubMed2001

Blunted vascular and renal effects of exogenous atrial natriuretic peptide in patients with cushing's disease.

The role of atrial natriuretic peptide (ANP) in glucocorticoid hypertension is still controversial, as glucocorticoids enhance the secretion of ANP in vivo, but reduce its biological activity in vitro. In isolated cells, for example, the cGMP response to ANP is suppressed by dexamethasone. We tested the in vivo relevance of this observation by comparing the cGMP, endocrine, and renal responses to exogenous ANP in patients with Cushing's disease (CD; n = 10) and in a matched group of essential hypertensives (EH; n = 8) and normotensive controls (N; n = 4). alpha-human-ANP was infused at 0.01 microg/kg/min for 120 min with a 30-min recovery period; hormonal and arterial pressure measurements were performed at 30-min intervals, and renal parameters were measured at baseline and after infusion. There was a 4-fold increase in plasma ANP in all groups, but the increments in plasma cGMP were about 50% lower in CD than in N and EH; urinary cGMP was similarly lower in CD (247 +/- 61 vs. 529 +/- 146 and 384 +/- 54 nmol/150 min, respectively). This was associated with a reduced peak increase in hematocrit in CD (+2.6 +/- 0.9%) compared with N (+6.6 +/- 0.9%) and EH (+7.1 +/- 0.7%; P < 0.05 CD vs. both); the diuretic and natriuretic effects of ANP were also lower in CD than in EH with very similar systemic pressure levels (382 +/- 63 vs. 848 +/- 130 mL/150 min, and 61 +/- 14 vs. 113 +/- 14 mmol/150 min, respectively; P < 0.05 for both). The increments in plasma and urinary cGMP in response to physiological doses of ANP are thus blunted in CD patients compared with those in N and EH. This biochemical defect is associated with reduced capillary permeability and a lesser diuretic and natriuretic effect. These data are compatible with an impairment of the biological activity of ANP in glucocorticoid hypertension in humans.

Adult↗
PubMedDate not supplied

Microcirculatory unit. Actual news.

The microcirculatory unit is the localization of important exchanges. Any disturbance in the state of equilibrium, though at first functional, quickly becomes organic. This imbalance can appear at the level of the secretion of prostaglandin modification of the capillary permeability, which may be the consequence of Paf Acether secretion. Free Radical release can disrupt the normal functioning of the cell wall. Venotonic drugs act at this level, assisting the return to normal histochemical equilibrium.

Capillaries↗
PubMed1975

Effect of various lysosomes and endotoxin on vascular permeability in frogs and mice.

Blood-lymph permeability increasing effects of frog liver lysosomes, Escherichia coli 0111 endotoxin, bradykinin and serotonin were demonstrated in frogs with a method developed by the authors. These actions were expressed in a faster dye saturation in the lymph as compared to that of the controls. 2. The method is based on the determinations of concentration of Evans blue transported as protein-bound dye into the lymph. 3. Frog liver and polymorphonuclear leukocyte lysosomes had a capillary permeability increasing action tested by local skin response when injecting Evans blue intravenously in mice. 4. All these phenomena are similar to events described earlier in mammalian systems.

Acid Phosphatase↗
PubMed1998

Calcium dobesilate: pharmacology and future approaches.

1. Calcium dobesilate (2,5-dihydroxybenzene sulfonate) is a drug commonly used in the treatment of diabetic retinopathy and chronic venous insufficiency. 2. The pharmacology of calcium dobesilate reveals its ability to decrease capillary permeability, as well as platelet aggregation and blood viscosity. 3. Furthermore, recent data show that calcium dobesilate increases endothelium-dependent relaxation owing to an increase in nitric oxide synthesis.

Animals↗
PubMed1985

[Regional blood flow of experimental brain tumors with special reference to effects of chemotherapy and radiotherapy].

Regional blood flow and capillary permeability in the experimental brain tumors and their surrounding brain tissue of rats were measured with quantitative 14C-antipyrine and 14C-alpha-aminoisobutyric acid (AIB) autoradiographic method. The pharmacokinetic implications with respect to drug delivery to tumor tissue and the effect of ionizing irradiation were discussed in these physiological measurement. A suspension of 1 X 10(4) rat glioma cells (E239 RG 12) was stereotactically implanted into the right basal ganglia of CD-Fisher rats, and spherical brain tumors developed 10-17 days after implantation with a diameter of 1--5 mm. Autoradiographic investigations were performed for rats with small tumors (1--2 mm in diameter) and large tumors (4--5 mm in diameter). The uniform blood flow (91.7 +/- 13.1 ml/100 g/min: mean +/- S.E.) was observed in small tumors with the patchy low flow area (56.7 +/- 12.5 ml/100 g/min) surrounding the tumor. In large tumors, the blood flow was markedly decreased in the central part of the tumor (28.3 +/- 2.4 ml/100 g/min) with a ring shaped high flow area in the peripheral part (59.3 +/- 5.9 ml/100 mg/min). The blood flow in the brain adjacent to the tumor (30.5 +/- 2.5 ml/100 g/min) was lower than that in the peripheral part of the tumor. The uptake of 14C-AIB was quite similar to that of 14C-antipyrine suggesting the smaller permeability in the central part of the tumor. Neuropathological studies did not reveal necrotic foci, but viable cells in these areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

Transcapillary exchange of strontium and sucrose in canine tibia.

The walls of haversian capillaries have been proposed as a physiologic membrane controlling flux of solute between blood and bone. In this study, capillary permeability to 85Sr and [14C]sucrose was estimated in the dog tibia by using indicator dilution techniques. Sucrose was chosen as a tracer because it is inert and has no known transport system. The mean (+/-SD) observed ratio of permeabilities of 85Sr and sucrose was 2.36 +/- 0.46 (N = 14) which is not substantially different from the ratio of their free diffusion coefficients, 2.55. This ratio was not influenced when the dogs were made hyperparathyroid by injection of parathyroid hormone (2.16 +/- 0.55; N = 11). This suggests that free diffusion is the principal mechanism for moving 85Sr across the bone capillary wall.

Animals↗
PubMed1984

Effect of lung injuries on [14C]urea permeability-surface area product in dogs.

To determine whether [14C]urea permeability-surface area product (PS) is a reliable indicator of changes in permeability in various injuries and its relationship to indicator-dilution and gravimetric lung water contents, we studied six groups of anesthetized, paralyzed, and mechanically ventilated dogs (5 animals each). The groups consisted of control dogs, those injured by intravenous alloxan, oleic acid, or glass beads, and those exposed to acute hypoxia or increased left atrial pressure from volume loading (Pla). Interanimal variation of PS was large (3.0-15.0 ml/s), but successive hourly values in individual animals were stable for 2 h in experimental groups and for 4 h in controls. The PS increased after alloxan, elevated Pla, and 2 h of hypoxia; PS decreased after oleic acid and microemboli. The gravimetric lung water increased after alloxan, oleic acid, and microemboli, and indicator-dilution lung water increased only after alloxan. We conclude 1) that intersubject variability requires normalization to enable detection of significant deviation from base line, and 2) that decreased PS after oleic acid and microvascular injury occurred because vascular obstruction, which decreased surface area, masked probable coexisting increases in capillary permeability.

Alloxan↗
PubMed2001

Effects of androgen deprivation on prostatic morphology and vascular permeability evaluated with mr imaging.

PURPOSE: To assess magnetic resonance (MR) measures of vascular permeability of prostate cancer treated with androgen deprivation and to correlate these with morphologic appearances and serum prostate-specific antigen (PSA) levels. MATERIALS AND METHODS: MR examinations in 56 consecutive patients with prostate cancer were performed before and after luteinizing hormone-releasing hormone analog treatment. T2-weighted and contrast medium-enhanced T1-weighted MR images were obtained. Pre- and posttreatment comparisons of morphologic features, glandular volume, and enhancement-related parameters (capillary permeability, leakage space, gadolinium accumulation) were made. RESULTS: Fifty-five tumors were seen before treatment; 42, after treatment. Signal intensity in the peripheral zone and seminal vesicles decreased on T2-weighted images in 42 (75%) and 25 (45%) patients, respectively. Median volume in tumor decreased by 65% (95% CI: 55%, 76%); in central gland, by 30% (95% CI: 25%, 35%). Reductions in tumor permeability (P <.001) and changes in washout patterns were observed (P <.001). Tumor permeability reductions coincided with a decrease in serum PSA levels in 91% of patients. A weak correlation between tumor permeability and volume change was seen (r = 0.55, P =.04). Reductions in peripheral zone (P <.001) and central gland (P =.009) permeability were noted. CONCLUSION: Androgen deprivation decreases tumor volume and vascular permeability and impairs detection of prostate cancers. Use of MR estimates of permeability may be an additional way of assessing prostatic tumor response to antiandrogen treatment.

Aged↗
PubMed2003

Dynamic contrast-enhanced MR imaging of VX2 carcinomas after X-irradiation in rabbits: comparison of gadopentetate dimeglumine and a macromolecular contrast agent.

RATIONALE AND OBJECTIVES: To compare enhancement patterns of gadomer-17 with those of gadopentetate dimeglumine in VX2 carcinomas after irradiation on rabbits. METHODS: Twelve rabbits with VX2 carcinoma in the thigh underwent dynamic contrast-enhanced magnetic resonance (MR) imaging with gadopentetate dimeglumine and gadomer-17 at 24-hour intervals before (n = 12), 3 days (group 1, n = 12), 1 month (group 2, n = 8) and 2 months (group 3, n = 4) after 30 Gy irradiation. After taking postirradiation MR images, 4 rabbits were killed for histopathologic examination at each time interval. The enhancement characteristics in MR imaging and morphology of tumor vessels in histopathologic specimen were assessed. RESULTS: After gadopentetate dimeglumine injection, the enhancement characteristics were not different among tumors before and after irradiation (P > 0.05). For gadomer-17, the enhancement ratios decreased after irradiation. The shape of the curves for tumor enhancement before irradiation was significantly different from curves of group 1(P < 0.05). The specimens from group 3 showed sclerosis and wall thickening in arterioles. CONCLUSIONS: Dynamic contrast-enhanced MR imaging with a gadomer-17 reveals increased capillary permeability at an early phase after irradiation and chronic obliterating vasculopathy at delayed phase.

Animals↗
PubMed1979

Leakage of fluorescein: first sign of juvenile diabetic retinopathy. Role of diabetic control and of duration of diabetes.

In order to ascertain the first vascular lesions responsible for juvenile diabetic retinopathy, 408 fluorescein angiographies were performed in 114 diabetic children and adolescents whose diabetes became clinically apparent before the age of 14 years. Compared with regular ophthalmoscopy, fluorescein angiography doubles the frequency of the diagnosis of incipient retinopathy. In addition to the classical diabetic lesions, fluorescein leakages are demonstrated in 50% of diabetic eyes with initial retinopathy. They probably reflect early changes in capillary permeability. They appear often before microaneurysms. Duration of diabetes as well as insufficient and poor metabolic control considerably increase the frequency of retinopathy.

Adolescent↗
PubMed1992

Correlation of bronchoalveolar lavage findings to severity of Pneumocystis carinii pneumonia in AIDS. Evidence for the development of high-permeability pulmonary edema.

We correlated bronchoalveolar lavage findings with the clinical course and outcome of Pneumocystis pneumonia. Forty-eight patients with AIDS and a confirmed diagnosis of P carinii pneumonia were studied. Patients with additional pulmonary infections were excluded. On the basis of BAL findings, they were divided into those with a low neutrophil count (less than 5 percent) and those with a high neutrophil count (greater than or equal to 5 percent). Sixteen patients with AIDS but without PCP served as a control group. All BAL fluid samples from the control group showed a low neutrophil count. The group with PCP and a high neutrophil count had more severe respiratory compromise and greater morbidity than the group with PCP and a low neutrophil count. Mortality rate was not different. The group showing a high BALF neutrophil count also showed a higher BALF protein concentration, a higher ratio of BALF protein concentration to plasma protein concentration, and the presence of alpha 2-globulins compared with other groups. These findings suggest that increased alveolar-capillary permeability occurs during severe PCP.

Acquired Immunodeficiency Syndrome↗
PubMed2001

The effects of dexamethasone therapy on permeability, blood flow and iNOS expression in experimental glioma.

Most studies of dexamethasone (DXN) effects on experimental glioma have used doses 10-500 higher (on mg/kg basis) than those used for patients with brain tumour. The relevance of findings to patients with glioma are therefore uncertain. In order to evaluate the effects of clinical doses of DXN (0.22 mg kg(-1)day(-1)) on the pathophysiology of an experimental glioma we have treated rodents with established C6 gliomas for 3 days. The effects of therapy on local cerebral blood flow (LCBF), tumour blood flow (TBF), tumour capillary permeability (TCP), and inducible nit ric oxide synthase (iNOS) mRNA expression were evaluated. DXN caused a significant reduction in TCP (21 +/- 1.9 to 7.7 +/- 2.2 ml.gm(-1)min(-1)10(-3)) and iNOS mRNA production within and around tumour, but no significant change in either TBF or LCBF. The reduction in TCP was identical to that reported after higher doses of DXN and is probably mediated by glucocorticoid receptors. Further in vivo stud ies using either behavioural or neuropathological paradigms in rodents with established cerebral glioma should be treated with similar doses of DXN to optimise clinical relevance.

Animals↗
PubMed1989

[Effects of oleanolic acid on immune system and type I allergic reaction].

Oleanolic acid (OLA)50, 100 mg/kg sc antagonised the inhibitory effect of cortisone on the weights of spleen and thymus, decreased the clearance rate of charcoal particles in mice. The production of serum specific antibody hemolysin was not clearly affected by OLA. The administration of OLA 100 mg/kg enhanced the development of serum antibody immunoglobulin G in mice and showed marked inhibition on the hemolytic activity of the total complement by classical pathway in guinea pigs. In addition, the homologous passive cutaneous anaphylaxis in mice or rats and the degranulation of mast cells of calvarial periosteum in rats were significantly prevented by OLA 50, 100 mg/kg. The increased capillary permeability in the rat skin caused by intradermic injection of histamine was also reduced by OLA 100 mg/kg. These results indicate that OLA inhibited the type I allergic reaction.

Animals↗
PubMed2003

Impairment of lymphatic function in women with gynoid adiposity and swelling syndrome.

The current study sought to investigate the factors, in particular anthropometric parameters, associated with an impairment of capillary permeability and lymphatic function in a large series of women complaining of a swelling syndrome. One hundred ninety-seven women with a swelling syndrome were investigated, 43 of whom were obese (body mass index [BMI]>30 kg/m2), 77 overweight (BMI=25 to 30 kg/m2). Thirty-five of the 197 women had abdominal adiposity (waist-to-hip ratio [WHR]>0.85). Capillary filtration of albumin and lymphatic function were studied by means of an isotopic test using 99mtechnetium-labeled albumin and venous compression. This test allowed measurement of interstitial albumin retention (AR) and the evaluation of lymphatic function by analyzing the radioactivity disappearance curve after removal of venous compression with the fast Fourier transform (low frequency/high frequency [LF/HF]). Body composition was studied by the bioelectrical impedance method. WHR correlated with fasting blood glucose (P=.03), serum triglyceride (P<.0001), and apoprotein B (P=.008) levels. AR was increased (> or =8 %) in 117 women (59.4%) and LF/HF (> or =1 %) in 149 cases (75.6%). Extracellular water (ECW) was increased (>107% of the theoretical value) in 144 cases (73.1%). LF/HF correlated negatively with age (P=.001), BMI (P=.006), WHR (P<.0001), and fat mass (P=.002). In the multivariate analysis taking age, BMI, and WHR as independent variables, LF/HF correlated significantly with WHR (P<.005). There was a trend to a higher prevalence of an increase in AR in the women with an increase in ECW (61.8 %) as compared with those without an increase in ECW (52.8%). We conclude that abdominal adiposity is associated with metabolic disorders secondary to insulin resistance as previously demonstrated, whereas lymphatic dysfunction is mainly associated with gynoid adiposity. Besides microcirculatory disorders, changes in the secretory regulation of hormones involved in salt and water retention are likely to play an important role in ECW excess.

Abdomen↗
PubMed1996

Endothelial dysfunction in diabetes mellitus.

In the present study, we examined the pattern of Evan's blue (EB) extravasation over time and we verified the effect of two inhibitors of aldose reductase (sorbinil and ARI 509) as well as aminoguanidine, which modulate nitric oxide (NO) production, on streptozotocin-induced capillary extravasation abnormalities in the upper bronchi, heart, kidney, duodenum, pancreas, skeletal muscle and skin. Albumin extravasation was measured using the EB technique (20 mg/kg). On the third day, a transient decrease in EB leakage was observed in the lung (-49%), heart (-29%) and skeletal muscle (-64%). These early changes in EB were transient, and values returned to normal there after. Later on, EB extravasation was significantly enhanced in the skin (+358, +680, +580, +525 and +365, respectively, at 2, 4, 5, 6 and 7 weeks of diabetes), the duodenum (+101, +160, +92, +124 and +76%), the upper bronchus (+70, +113, +70, +41 and +25%) and the pancreas (+43, +102, +46, +15 and +78%). In the kidney, the increase of EB extravasation was significant at 2 weeks (26%), and from 5 to 7 weeks (+12, +22, +36%). The chronic treatment of diabetic rats with aminoguanidine normalized capillary permeability in most tissues, suggesting that NO is involved in the development of endothelium dysfunction in this streptozotocin-induced diabetic model. Treatment with aldose reductase inhibitors selectively normalized EB extravasation in the kidney.

Aldehyde Reductase↗