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Capillary Permeability (capillary + permeability)
Selected AbstractsCapillary permeability and extracellular volume fraction in uterine cervical cancer as patient outcome predictors: Measurements by using dynamic MRI spin-lattice relaxometryJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2008Véronique Dedieu PhD Abstract Purpose To improve the outcome prediction of uterine cervical carcinoma by measuring the vascular permeability (kep) and the extracellular volume fraction (ve) of the tumor from Dynamic T1 - IRM Relaxometry. Materials and Methods Twenty-six patients with proven cervical carcinoma were divided into good outcome and poor outcome groups. Classic tumor prognostic factors, the longest diameter L and the volume V of the tumor, were measured from morphologic MR images. The tumor parameters kep and ve were determined from the relaxometry time-curve acquired during the contrast uptake after a bolus intravenous injection of an extracellular contrast agent. Results All "small" tumors (L<35 mm or V<11 cm3) were good outcome with 100% sensitivity but a rather low specificity (36% and 43% for L and V, respectively). With regard to the physiopathological parameter kep, "large" tumors (L , 35mm) can also be classified as good outcome on the condition that kep , 2.2 min,1 with 100% sensitivity and 89% specificity. Regarding the extracellular volume fraction (ve), no significant difference was observed between the two groups. Conclusion Measurement of the tumor vascular permeability might be useful to predict prognostic, to evaluate the treatment efficacy, and to adapt a proper therapy schedule. J. Magn. Reson. Imaging 2008;27:846,853. © 2008 Wiley-Liss, Inc. [source] The rapidly adapting receptors in mammalian airways and their responses to changes in extravascular fluid volumeEXPERIMENTAL PHYSIOLOGY, Issue 4 2006C. Tissa Kappagoda In this short review, we shall focus on some recent findings on the physiological stimulus for the rapidly adapting receptors (RAR) of the airways. They are readily activated by a sustained inflation of the lungs and they are usually identified by their rapid adaptation to this stimulus. They are also activated by both tactile stimuli and irritant gases applied to the epithelium of the airways. The investigations reviewed here suggest that these receptors are activated by changes in extravascular fluid volume. The principal factors governing fluid flux from the microcirculation are identified in the Starling equation. These are the hydrostatic pressure, plasma oncotic pressure and capillary permeability. Findings from recent studies suggest that all these factors increase the activity of RAR. In addition, these receptors are also activated by obstruction of lymph drainage from the lung. Evidence is presented to show that manipulation of Starling forces also increases the extravascular fluid volume of the airways in areas where the RAR are located. On the basis of these findings, it is suggested that, along with mechanosensitivity to stimuli such as stretch, inflation and deflation, another physiological stimulus to the RAR is a change in extravascular fluid volume in the regions of the airways where these receptors are located. [source] Improvement of Subcutaneous Bioavailability of Insulin by Sulphobutyl Ether ,-Cyclodextrin in RatsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2000KEIICHI TOKIHIRO The objective of this study was to examine and compare how hydrophilic ,-cyclodextrin derivatives (,-CyDs) improve the bioavailability of insulin following subcutaneous injection of insulin solution in rats. When insulin solutions in the absence of ,-CyDs were injected into the dorsal subcutaneous tissues of rats, the absolute bioavailability of insulin calculated from plasma immunoreactive insulin (IRI) levels was approximately 50%. When maltosyl-,-cyclodextrin was added to the solutions, there was no change in the plasma IRI levels and hypoglycaemia compared with those of the insulin-alone solution. Dimethyl-,-cyclodextrin decreased the bioavailability of insulin, although it increased the maximal concentration of IRI in plasma and the capillary permeability of the fluorescein isothiocyanatedextran 40, a non-degraded permeation marker. When insulin solutions containing sulphobutyl ether-,-cyclodextrin with a degree of substitution of the sulphobutyl group of 3,9 (SBE4-,-CyD) were injected, the IRI level rapidly increased and maintained higher IRI levels for at least 8h. The bioavailability of the insulin/SBE4-,-CyD system was about twice that of insulin alone and approached 96%. The enhancing effects of SBE4-,-CyD may be in part due to the inhibitory effects of SBE4-,-CyDs on the enzymatic degradation and/or the adsorption of insulin onto the subcutaneous tissue at the injection site, although this does not apparently facilitate capillary permeability. These results suggest that SBE4-,-CyD in aqueous insulin injection for subcutaneous administration is useful for improving the bioavailability and the hence the pharmacological effects of insulin. [source] Bilastine in allergic rhinoconjunctivitis and urticariaALLERGY, Issue 2010C. Bachert To cite this article: Bachert C, Kuna P, Zuberbier T. Bilastine in allergic rhinoconjunctivitis and urticaria. Allergy 2010; 65 (Suppl. 93): 1,13. Abstract Allergic rhinoconjunctivitis and urticaria are increasing in prevalence in many developed countries. The role of histamine in such conditions is well documented and clinical guidelines recommend non-sedating H1 -receptor antagonists as first-line treatment choices. Bilastine is a novel non-sedating histamine H1 -receptor antagonist developed for the treatment of allergic rhinoconjunctivitis and urticaria. The aim of this review is to critique the scientific evidence relating to the pharmacological properties of bilastine and the clinical evidence regarding its potential as an antihistamine. In vitro binding studies and investigations in animal tissue have demonstrated the high specificity of bilastine for H1 -receptors, and preclinical animal studies have also yielded promising results in terms of a reduction of histamine-mediated inflammatory effects, including capillary permeability and bronchospasm. In pharmacodynamic studies bilastine was found to down-regulate histamine-induced flare and wheal responses in healthy volunteers. Preclinical and clinical pharmacokinetic studies showed that bilastine has dose-dependent kinetics following oral administration. Excretion is almost exclusively via urine and faeces as unchanged drug. Early clinical trials have shown that bilastine has similar efficacy to other second-generation H1 -receptor antagonists such as cetirizine, desloratadine, fexofenadine and levocetirizine, in terms of reducing allergic symptoms. Clinical findings also indicate that bilastine has a rapid onset of action and a 20 mg single dose is effective throughout a 24-h period. Furthermore, bilastine has been associated with improved quality of life in allergic rhinoconjunctivitis and urticaria patients. Adverse effects have generally been minimal in these studies and doses up to twice those proposed did not exhibit differences in adverse events compared to placebo. Moreover, in vivo investigations have found no evidence of accumulation of bilastine in the central nervous system, and various studies have confirmed minimal effects on psychomotor performance in healthy volunteers administered up to four times the usual dose. Clinical studies have also found no effect of bilastine on the QTc interval and other ECG parameters, even at supratherapeutic dosages, confirming the good cardiac safety profile of this newer antihistamine. Given its pharmacodynamic profile, which appears to be similar to other second-generation H1 -receptor antagonists, and its favourable safety and tolerability, bilastine has the attributes of a potentially clinically useful non-sedating antihistamine. Larger clinical studies are now necessary to fully elucidate the clinical potential of this novel antihistamine. [source] Microvascular Solute and Water TransportMICROCIRCULATION, Issue 1 2005FITZ-ROY E. CURRY ABSTRACT Objective: This review evaluate [1] the regulation of water and solute transport across the endothelial barrier in terms of pore theory and the glycocalyx-junction-break model of capillary permeability; and [2] the mechanisms regulating permeability based on experiments using cultured endothelial cells and intact microvessels. Conclusions: The current form of the glycocalyx-junction-break model of capillary permeability describes the selectivity of the capillary wall (pore size) in terms of the space between the fibers of a quasi-periodic matrix on the endothelial cell surface and the area for exchange (pore number) in terms of the length and frequency of breaks in the tight junction strands. An independent test of this model in a range of mammalian microvascular beds is new experimental evidence that the colloid osmotic pressure of plasma proteins is developed across the glycocalyx, not across the whole microvessel wall. We are beginning to understand that endothelial cells may change their phenotype in response to physical and chemical stresses. Such changes in phenotype may explain changes in the regulation of endothelial barrier function in intact microvessels that have previously been exposed to injury and differences in the regulation of contractile mechanisms between endothelial cells in vivo and in vitro. [source] Non-cardiogenic pulmonary edema during basiliximab induction in three adolescent renal transplant patientsPEDIATRIC TRANSPLANTATION, Issue 4 2003Fatai O. Bamgbola Abstract:, Background:, Introduction of the anti-CD-25 mAb basiliximab into renal transplant protocols has reduced the incidence of acute rejection. However, its side-effect profile is still unfolding. We report three adolescents who developed severe non-cardiogenic PE within 2 days of renal transplantation. Methods:, Pretransplant cardiorespiratory evaluation was normal in all cases. Transplant immunosuppression consisted of basiliximab induction, corticosteroids, and tacrolimus. Patients received standard fluid management during and after the transplant surgery. Case reports:, Patients 1 and 2 were 17- and 21-yr-old females. Pretransplant Hct values were 35 and 25% respectively. Each received 5-L normal saline during surgery. EBL was 200 and 500 mL in patients 1 and 2, respectively. There was immediate post-operative diuresis. Both developed non-cardiogenic PE by POD no. 2. BIPAP and PRVC were administered respectively. In both cases PE resolved within 1 wk. Patient 3 was a 19-yr-old male with pretransplant Hct of 43% who received a cadaveric renal transplant after 23.5-h cold-ischemia; 3.5 L normal saline was given during surgery. EBL was 100 mL. Non-cardiogenic PE ensued on POD no. 2 warranting assisted ventilation. The patient died following a sudden cardiopulmonary arrest on POD no. 3. Conclusions:, Potential mechanisms for the development of PE include cytokine release from basiliximab with increased capillary permeability, volume overload and ischemic-reperfusion injury. Improved awareness of this potential complication, prudent fluid management, and efforts to minimize graft-ischemia are recommended to prevent further cases. [source] Pharmacological studies on Indian black tea (leaf variety) in acute and chronic inflammatory conditionsPHYTOTHERAPY RESEARCH, Issue 6 2008Dilip K. Roy Abstract Infusions of Indian black tea (BTI), when administered orally, produced significant inhibition of rat paw oedema, induced with carrageenin (pre and post treatment) and arachidonic acid. BTI was also found to inhibit peritoneal capillary permeability and caused a marked reduction of lipopolysaccharide induced PGE2 generation. In these models, the observed antioedema effect was similar to that of BW755C (a dual inhibitor of cyclooxygenase and 5-lipoxygenase enzymes). BTI was found to scavenge superoxide and hydroxyl radicals, and also protected rat erythrocytes from the damaging effects of hydrogen peroxide. In chronic studies, BTI inhibited granuloma formation along with the reduction of both lipid peroxidation and hydroxyproline content (in the granuloma tissue). Significant antiarthritic activity was observed with regular administration of BTI in the Freund's adjuvant induced model of arthritis. Chronic treatment with BTI (in arthritic rats) resulted in a decrease of paw diameter and tissue lipid peroxidation, along with a restoration of GSH, catalase and superoxide dismutase levels. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||