Search results for "Permeability"
showing 10 items of 596 documents
Endothelial Cell Swelling and Brain Perfusion
1997
Background: Whereas the contribution of glial swelling to no-reflow conditions in the ischemic penumbra or during reperfusion after global ischemia is widely discussed, little is known about cell volume control of endothelial cells under reperfusion conditions. Methods: The effect of extracellular acidosis-a key mediator of secondary brain damage-on cell volume was studied in the GM7373 endothelial cell line. Experiments were performed at pH = 6.0 in the presence or absence of bicarbonate, and during exposure to inhibitors of specific transport systems such as ethyl isopropyl amiloride or 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid. Results: Endothelial swelling to 111.1 ± 3.4% was f…
Cationic lipide mediated transfer of c-abl and bcr antisense oligonucleotides to immature normal myeloid cells: Uptake, biological effects and modula…
1996
Uptake and biochemical and biological effects of antisense oligodeoxynucleotides (ODN) specific for c-abl and bcr genes were studied in normal immature myeloid cells. CD34-positive cells were purified by positive and negative selection and cultured in liquid culture for 7 days. These cells were then incubated with ODNs, either alone or in combination with cationic lipids. The uptake of ODNs was enhanced by the use of cationic lipids. In addition, very low concentrations of ODNs in combination with cationic lipids were capable of specifically inhibiting the expression of the c-abl gene. In contrast, no effects were seen on the expression of bcr. However, despite the effective blocking of c-a…
Oral local drug delivery and new perspectives in oral drug formulation
2012
Modern pharmaceutical science has provided us with a wide range of substances to be administered with a wide large variety of dosage forms. Local drug delivery systems have been used for a long time; in particular, for the local therapy of diseases affecting the oral cavity. Although these diseases are often extremely responsive to local therapy, the mouth often presents various difficulties in the application of topical compounds (owing to saliva and the mouth's different functions), resulting in a short retention time of dosage forms with a consequent low therapeutic efficacy. To resolve these limitations, research today concentrates on the development of bioadhesive formulations. This re…
Efficacy of protection by latex gloves during orthodontic therapy.
2000
The wearing of gloves during orthodontic or dental treatment is generally indicated for reasons of hygiene and protection against infection. This study was aimed at determining the extent and localization of perforations caused by the various orthodontic treatment techniques and interrupting the infection barrier. The impermeability was tested by means of a water retention test according to European standard EN 455, Part 1, performed on 1600 Centramed (Centramed, Koblenz), Tekmedic and SafeEx non-sterile disposable latex gloves (both by Safe Med, Switzerland) and Safe Gan latex gloves with an additional acrylate coating (also by Safe Med). The perforation rate in unused gloves was between 0…
Exertional hematuria: definition, epidemiology, diagnostic and clinical considerations
2019
Abstract Exertional hematuria can be considered a subcategory of exercise-induced hematuria, characterized by painless appearance of erythrocytes in urine after recent physical exercise, not directly attributable to external traumatic injuries to the genitourinary system, and spontaneously resolving with rest. Although its frequency has enormous heterogeneity, depending on the athlete population, duration and intensity of exercise, technique used for identifying or quantifying hematuria and relative diagnostic thresholds, what clearly emerges from the scientific literature is that a certain degree of hematuria is commonplace after non-contact sports, especially running. This exertional hema…
Intestinal filtration as a consequence of increased mucosal hydraulic permeability
1980
Two mechanisms have been proposed to explain the secretory action of laxative compounds in the intestine: 1. increase of the intracellular amount of cyclic adenosine monophosphate due to stimulation of the adenylate cyclase system and 2. inhibition of intestinal transfer processes, in particular the Na,K-ATPase activated sodium absorption. In a set of in vivo and in vitro experiments in rat colon it could be demonstrated that dihydroxy bile acids (deoxycholate) and diphenolic laxatives (oxyphenisatin) enhance the hydraulic permeability of the mucosal tissue. The permeability changes take place--and there is good experimental evidence--at the zonulae occludentes which bind the epithelial cel…
Stimulatory effects of DB-c-AMP and adrenaline on myocardial contraction and 45Ca exchange. Experiments at reduced calcium concentration and low freq…
1973
The effects of adrenaline (2.2×10−6 M) and cyclic N6-2′-O-dibutyryl-adenosine-3′,5′-monophosphate (DB-c-AMP; 10−3 M) on mechanical performance, 45Ca uptake and total tissue calcium concentration were investigated in electrically stimulated left auricles isolated from female rats weighing 180–220 g. The experiments were performed at reduced [Ca]e of 0.45 mM and at various frequencies of stimulation (0–120 beats/min). In the first series of experiments 45Ca incubation time was 5 min. Under these conditions DB-c-AMP as well as adrenaline enhanced contractile force to 300–450% of the control values at all frequencies tested (Fig.1). This increase in contractile force was accompanied by a signif…
Aging of the liver: Age-associated mitochondrial damage in intact hepatocytes
1996
Mitochondrial damage may be a major cause of cellular aging. So far, this hypothesis had only been tested using isolated mitochondria. The aim of this study was to investigate the involvement of mitochondria in aging using whole liver cells and not isolated mitochondria only. Using flow cytometry, we found that age is associated with a decrease in mitochondrial membrane potential (30%), an increase in mitochondrial size, and an increase in mitochondrial peroxide generation (23%). Intracellular peroxide levels were also increased. The number of mitochondria per cell and inner mitochondrial membrane mass did not change. Gluconeogenesis from glycerol or fructose (mitochondrial-independent) did…
Influence of polyunsaturated fatty acids on Cortisol transport through MDCK and MDCK-MDR1 cells as blood-brain barrier in vitro model.
2011
Abstract Transport across the blood–brain barrier is a relevant factor in the pharmacological action of many drugs and endogenous substances whose action site is located in brain. An overactive P-gp has been suggested to be of relevance for the resistance of the HPA system to be suppressed by glucocorticoids, which is one of the best described biological abnormalities in certain types of depression. PUFA acids have shown clinical efficacy in depressed patients and the hypothesis is that these compounds are able to reduce HPA axis activity as this effect has been shown in animal models of depression. The objective of the present work was (1) to characterize Cortisol transport through MDCK an…