Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Lumen medium.
Articles de revues sur le sujet « Lumen medium »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Lumen medium ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Köhler, Michael, Matthias C. Burg, Alexander C. Bunck, Walter Heindel, Harald Seifarth et David Maintz. « Dual-Source CT Angiography of Peripheral Arterial Stents : In Vitro Evaluation of 22 Different Stent Types ». Radiology Research and Practice 2011 (2011) : 1–7. http://dx.doi.org/10.1155/2011/103873.
Texte intégralRésumé :
Purpose. To test different peripheral arterial stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation and image noise in dual-source multidetector row CT (DSCT) in vitro.Methods and Materials. 22 stents (nitinol, steel, cobalt-alloy, tantalum, platinum alloy) were examined in a vessel phantom. All stents were imaged in axial orientation with standard parameters. Image reconstructions were obtained with four different convolution kernels. To evaluate visualization characteristics of the stent, the lumen diameter, intraluminal density and noise were measured.Results. The mean percentage of the visible stent lumen diameter from the nominal stent diameter was 74.5% ± 5.7 for the medium-sharp kernel, 72.8% ± 6.4 for the medium, 70.8% ± 6.4 for the medium-smooth and 67.6% ± 6.6 for the smooth kernel. Mean values of lumen attenuation were 299.7HU ± 127 (medium-sharp), 273.9HU ± 68 (medium), 270.7HU ± 53 (medium-smooth) and 265.8HU ± 43. Mean image noise was: 54.6 ± 6.3, 20.5 ± 1.7, 16.3 ± 1.7, 14.0 ± 2 respectively.Conclusion. Visible stent lumen diameter varies depending on stent type and scan parameters. Lumen diameter visibility increases with the sharpness of the reconstruction kernel. Smoother kernels provide more realistic density measurements inside the stent lumen and less image noise.
2
Leese, H. J., et S. M. Gray. « Vascular perfusion : a novel means of studying oviduct function ». American Journal of Physiology-Endocrinology and Metabolism 248, no 5 (1 mai 1985) : E624—E632. http://dx.doi.org/10.1152/ajpendo.1985.248.5.e624.
Texte intégralRésumé :
An in situ preparation for the combined vascular and luminal perfusion of the rabbit oviduct has been developed. Medium 199, gassed with 5% CO2 in O2 and supplemented with heparin, antibiotics, and 2.5% wt/vol dialyzed bovine serum albumin was infused into the ovarian artery at a rate of 1 ml/min. Krebs Ringer bicarbonate medium was recirculated through the lumen at a rate of 50 microliter/min. The ovary was perfused together with the oviduct, and the preparation is viable for up to 3 h. Equal concentrations of pyruvate, lactate, glucose, and sucrose added to the vascular medium were transported at different rates into the lumen, as was a physiological mixture of amino acids. A proportion of the lactate entering the lumen was synthesized within the oviduct from vascular glucose. When glucose and pyruvate were omitted from the vascular medium, their appearance and that of lactate in the lumen was barely detectable, suggesting that these oviduct fluid components are mainly derived from the blood. The oviduct maintained a steady transmural potential difference of 5.9 mV (lumen negative). With vascular perfusion alone, oviduct fluid entered the oviduct lumen at a rate of 16.8 microliter/h. In oviducts taken from rabbits 3 days postovulation, there was a general decrease in the vascular to lumen flux of all nutrients measured. Preliminary work has shown that the preparation may be used to study ovulation, ovum pickup and transport, and fertilization.
3
Wallace, Darren P., Lorraine A. Rome, Lawrence P. Sullivan et Jared J. Grantham. « cAMP-dependent fluid secretion in rat inner medullary collecting ducts ». American Journal of Physiology-Renal Physiology 280, no 6 (1 juin 2001) : F1019—F1029. http://dx.doi.org/10.1152/ajprenal.2001.280.6.f1019.
Texte intégralRésumé :
We used an unambiguous in vitro method to determine if inner medullary collecting ducts (IMCD) have intrinsic capacities to absorb and secrete solutes and fluid in an isotonic medium. IMCD1, IMCD2, and IMCD3 were dissected from kidneys of young Sprague-Dawley rats. 8-Bromo-3′,5′-cyclic monophosphate (8-BrcAMP) stimulated lumen formation and progressive dilation in all IMCD subsegments; lumen formation was greatest in IMCD1.Benzamil potentiated the rate of lumen expansion in response to 8-BrcAMP. Fluid entered tubule lumens by transcellular secretion rather than simple translocation of intracellular fluid. Secreted lumen solutes were osmometrically active. Inhibition of protein kinase A with H-89 and Rp diastereomer of adenosine 3′,5′-cyclic monophosphorothioate blocked fluid secretion. The rate of lumen expansion was reduced by the selective addition of ouabain, barium, diphenyl-2-carboxylate, bumetanide, glybenclamide, or DIDS, or reduction of extracellular Cl−. We conclude that IMCD absorb and secrete electrolytes and fluid in vitro and that secretion is accelerated by cAMP. We suggest that salt and fluid secretion by the terminal portions of the renal collecting system may have a role in modulating the composition and volume of the final urine.
4
Newman, Andrew C., Martin N. Nakatsu, Wayne Chou, Paul D. Gershon et Christopher C. W. Hughes. « The requirement for fibroblasts in angiogenesis : fibroblast-derived matrix proteins are essential for endothelial cell lumen formation ». Molecular Biology of the Cell 22, no 20 (15 octobre 2011) : 3791–800. http://dx.doi.org/10.1091/mbc.e11-05-0393.
Texte intégralRésumé :
A role for fibroblasts in physiological and pathological angiogenesis is now well recognized; however, the precise mechanisms underlying their action have not been determined. Using an in vitro angiogenesis model in combination with a candidate gene approach, column chromatography, and mass spectrometry, we identify two classes of fibroblast-derived factors—one that supports vessel sprouting but not lumen formation, and one that promotes lumen formation. In the absence of fibroblasts a combination of angiopoietin-1, angiogenin, hepatocyte growth factor, transforming growth factor-α, and tumor necrosis factor drives robust endothelial cell (EC) sprouting; however, lumens fail to form. Subsequent addition of fibroblast-conditioned medium restores lumenogenesis. Using small interfering RNA–mediated knockdown, we show that five genes expressed in fibroblasts—collagen I, procollagen C endopeptidase enhancer 1, secreted protein acidic and rich in cysteine, transforming growth factor-β–induced protein ig-h3, and insulin growth factor–binding protein 7—are necessary for lumen formation. Moreover, lumen formation can be rescued by addition of purified protein to knockdown cultures. Finally, using rheology, we demonstrate that the presence of these matricellular proteins results in significantly stiffer gels, which correlates with enhanced lumen formation. These findings highlight the critical role that fibroblast-derived extracellular matrix components play in EC lumen formation and provide potential insight into the role of fibroblasts in the tumor microenvironment.
5
Miller, D. S., G. Fricker, U. Schramm, J. H. Henson, D. N. Hager, S. Nundy, N. Ballatori et J. L. Boyer. « Active microtubule-dependent secretion of a fluorescent bile salt derivative in skate hepatocyte clusters ». American Journal of Physiology-Gastrointestinal and Liver Physiology 270, no 6 (1 juin 1996) : G887—G896. http://dx.doi.org/10.1152/ajpgi.1996.270.6.g887.
Texte intégralRésumé :
Fluorescence microscopy and video image analysis were used to study the transport of a fluorescent bile acid derivative [N-[7-(4-nitrobenzo-2-oxa-1,3-diazol)]-7 beta-amino-3 alpha, 12 alpha-dihydroxy-5 beta-cholan-24-oyl-2-aminoethanesulfonate (NBD-TC)] in isolated clusters of hepatocytes from the little skate Raja erinacea. Analysis of images of hepatocyte clusters that were incubated in medium with 0.5-1 microM NBD-TC showed that the fluorescent derivative accumulated in the cells and that the clusters retained a patent canalicular lumen as well as the ability to actively transport the bile acid derivative from the cells into the lumen; i.e., the lumen-to-cell fluorescence ratio greatly exceeded unity. NBD-TC uptake by hepatocytes was inhibited by several organic anions, of which taurocholate was the most effective. Uptake was also blocked by metabolic inhibitors and by incubation in the cold. Neither Na replacement nor increased medium K, which depolarizes the membrane electrical potential [potential difference (PD)], affected NBD-TC accumulation by hepatocytes. Transport of NBD-TC into the canalicular lumen was inhibited by incubation in the cold and was substantially reduced by high-K medium; these blocks were removed by warming and transfer to normal-K medium, respectively. Treatment of hepatocytes with 20-40 microM nocodazole, a drug that reversibly depolymerizes microtubules, reduced cellular NBD-TC accumulation and blocked its secretion into the canalicular lumen; nocodazole effects were reversed by washing the hepatocyte clusters in drug-free medium. Thus uptake of NBD-TC by skate hepatocytes is active and carrier mediated but not dependent on the PD or Na gradient. NBD-TC secretion from cell to canalicular lumen also appears to be active and carrier mediated. Canalicular secretion appears to be driven at least in part by the PD and is highly dependent on an intact microtubular system in this marine species.
6
Vernon, Robert B., Michel D. Gooden, Christina K. Chan, Gail Workman, Masanari Obika et Thomas N. Wight. « Autocrine Hyaluronan Influences Sprouting and Lumen Formation During HUVEC Tubulogenesis In Vitro ». Journal of Histochemistry & ; Cytochemistry 69, no 6 (juin 2021) : 415–28. http://dx.doi.org/10.1369/00221554211022703.
Texte intégralRésumé :
Although many studies have focused on a role for hyaluronan (HA) of interstitial extracellular matrix (presumably produced by non-vascular “stromal” cells) in regulating vascular growth, we herein examine the influence of “autocrine HA” produced by vascular endothelial cells themselves on tubulogenesis, using human umbilical vein endothelial cells (HUVECs) in angiogenic and vasculogenic three-dimensional collagen gel cultures. Relative to unstimulated controls, tubulogenic HUVECs upregulated HAS2 mRNA and increased the synthesis of cell-associated HA (but not HA secreted into media). Confocal microscopy/immunofluorescence on cultures fixed with neutral-buffered 10% formalin (NBF) revealed cytoplasmic HAS2 in HUVEC cords and tubes. Cultures fixed with NBF (with cetylpyridinium chloride added to retain HA), stained for HA using “affinity fluorescence” (biotinylated HA-binding protein with streptavidin-fluor), and viewed by confocal microscopy showed HA throughout tube lumens, but little/no HA on the abluminal sides of the tubes or in the surrounding collagen gel. Lumen formation in angiogenic and vasculogenic cultures was strongly suppressed by metabolic inhibitors of HA synthesis (mannose and 4-methylumbelliferone). Hyaluronidase strongly inhibited lumen formation in angiogenic cultures, but not in vasculogenic cultures (where developing lumens are not open to culture medium). Collectively, our results point to a role for autocrine, luminal HA in microvascular sprouting and lumen development. (J Histochem Cytochem 69: 415–428, 2021)
7
Miller, D. S., S. Letcher et D. M. Barnes. « Fluorescence imaging study of organic anion transport from renal proximal tubule cell to lumen ». American Journal of Physiology-Renal Physiology 271, no 3 (1 septembre 1996) : F508—F520. http://dx.doi.org/10.1152/ajprenal.1996.271.3.f508.
Texte intégralRésumé :
The mechanisms driving organic anion transport from cell to lumen were studied in intact killifish proximal tubules using fluorescence microscopy. Three fluorescent substrates were used as follows: 1) fluorescein (FL); 2) carboxyfluorescein (CF), generated intracellularly from carboxyfluorescein diacetate (CFDA); and 3) bimane-S conjugates, generated intracellularly by conjugation of monochlorobimane (MCB) with glutathione (GSH) and subsequent metabolism. The latter two substrates bypassed the basolateral uptake mechanism, allowing direct study of luminal transport mechanisms. At steady state, for all three substrates, luminal fluorescence was two to three times higher than cellular fluorescence. With FL as substrate, addition of p-aminohippurate (PAH) or probenecid to the incubation medium reduced cellular and luminal fluorescence to roughly the same extent. With CFDA or MCB as substrate, PAH and probenecid only slightly reduced cellular fluorescence but greatly reduced luminal fluorescence. MCB blocked transport of FL from cell to lumen; CFDA blocked transport of bimane-S conjugates from cell to lumen. Finally, depolarizing tubule cells with high-potassium medium did not affect the steady-state lumen-to-cell distribution of FL, CF, or bimane-S conjugates. These results show that organic anion transport from cell to lumen is mediated and uphill but not sensitive to the electrical potential difference across the luminal membrane.
8
Masereeuw, R., F. G. Russel et D. S. Miller. « Multiple pathways of organic anion secretion in renal proximal tubule revealed by confocal microscopy ». American Journal of Physiology-Renal Physiology 271, no 6 (1 décembre 1996) : F1173—F1182. http://dx.doi.org/10.1152/ajprenal.1996.271.6.f1173.
Texte intégralRésumé :
Previous studies with p-aminohippurate (PAH) and fluorescein (FL) have shown that cellular uptake and tubular secretion of organic anions is driven by indirect coupling to sodium. Here we used killifish proximal tubules and laser-scanning confocal microscopy to study the transport of a larger organic anion, fluorescein-methotrexate (FL-MTX, mol mass 923 Da). When tubules were incubated in medium containing 2 microM FL-MTX, dye accumulated in both cells and tubular lumens. At steady state, luminal fluorescence was 4-5 times higher than cellular fluorescence. Ouabain (0.1 mM) did not affect cellular or luminal fluorescence, and replacement of medium sodium by N-methylglucamine had only a modest effect; preincubation with glutarate had no effect. KCN did not affect cellular uptake but abolished secretion into the lumen. Uptake and secretion of FL-MTX were inhibited by micromolar concentrations of other organic anions (MTX, folate, probenecid, bromocresol green, bromosulfophthalein), but 1 mM PAH had a relatively small effect. FL-MTX secretion into the lumen was inhibited by leukotriene C4, cyclosporine A, and verapamil, none of which affected FL transport. Thus a substantial component of FL-MTX secretion is Na independent and ouabain insensitive. Both the basolateral and luminal steps in the Na-independent pathway differ from those usually associated with FL and PAH secretion.
9
Engle, M. J., M. L. Grove, M. J. Becich, A. Mahmood et D. H. Alpers. « Appearance of surfactant-like particles in apical medium of Caco-2 cells may occur via tight junctions ». American Journal of Physiology-Cell Physiology 268, no 6 (1 juin 1995) : C1401—C1413. http://dx.doi.org/10.1152/ajpcell.1995.268.6.c1401.
Texte intégralRésumé :
Intestinal alkaline phosphatase (AP) is secreted by Caco-2 cells bound to surfactant-like particles (SLP), which can be localized by electron microscopy to the basolateral space and the intestinal lumen, especially over tight junctions. To investigate the hypothesis that SLP are secreted basolaterally and enter the lumen through the tight junction, Caco-2 cells were incubated with agents known to increase permeability at tight junctions. Cytochalasin D and phorbol 12-myristate 13-acetate increased Caco-2 cell monolayer permeability and the appearance of particles in apical medium two- to threefold, as monitored by mannitol movement and AP activity, respectively. Blocking the apical secretory pathway by nocodazole or colchicine had no effect on either parameter. Estimation of SLP content demonstrated an increase in apical media particles similar to that determined by AP activity. Quantitative image analysis established that apical SLP content increased 4-10 times, whereas total cell particle content remained unchanged. These data indicate that SLP may be secreted initially into the basolateral space and then transported to the intestinal lumen through the tight junctions.
10
He, Muchun, Jiankai Wei, Yuting Li et Bo Dong. « Nuclear Factor of Activated T Cells-5 Regulates Notochord Lumenogenesis in Chordate Larval Development ». International Journal of Molecular Sciences 23, no 22 (19 novembre 2022) : 14407. http://dx.doi.org/10.3390/ijms232214407.
Texte intégralRésumé :
Osmoregulation is essential for organisms to adapt to the exterior environment and plays an important role in embryonic organogenesis. Tubular organ formation usually involves a hyperosmotic lumen environment. The mechanisms of how the cells respond and regulate lumen formation remain largely unknown. Here, we reported that the nuclear factor of activated T cells-5 (NFAT5), the only transcription factor in the NFAT family involved in the cellular responses to hypertonic stress, regulated notochord lumen formation in chordate Ciona. Ciona NFAT5 (Ci-NFAT5) was expressed in notochord, and its expression level increased during notochord lumen formation and expansion. Knockout and expression of the dominant negative of NFAT5 in Ciona embryos resulted in the failure of notochord lumen expansion. We further demonstrated that the Ci-NFAT5 transferred from the cytoplasm into nuclei in HeLa cells under the hyperosmotic medium, indicating Ci-NFAT5 can respond the hypertonicity. To reveal the underly mechanisms, we predicted potential downstream genes of Ci-NFAT5 and further validated Ci-NFAT5-interacted genes by the luciferase assay. The results showed that Ci-NFAT5 promoted SLC26A6 expression. Furthermore, expression of a transport inactivity mutant of SLC26A6 (L421P) in notochord led to the failure of lumen expansion, phenocopying that of Ci-NFAT5 knockout. These results suggest that Ci-NFAT5 regulates notochord lumen expansion via the SLC26A6 axis. Taken together, our results reveal that the chordate NFAT5 responds to hypertonic stress and regulates lumen osmotic pressure via an ion channel pathway on luminal organ formation.
11
Özgüneş, N. « Microvesiculation of the microvilli provides a membranous medium within the lumen during digestion ». Medical Hypotheses 46, no 4 (avril 1996) : 319–22. http://dx.doi.org/10.1016/s0306-9877(96)90179-6.
Texte intégral
12
Yan, Xiaoqin, Nan Xiang, Weikun Hu, Rong Liu et Ban Luo. « Characteristics of lacrimal passage diseases by 80-MHz ultrasound biomicroscopy : an observational study ». Graefe's Archive for Clinical and Experimental Ophthalmology 258, no 2 (10 décembre 2019) : 403–10. http://dx.doi.org/10.1007/s00417-019-04515-8.
Texte intégralRésumé :
Abstract Purpose To investigate the microstructure of the lacrimal canaliculus and the characteristics of lacrimal canalicular diseases by 80-MHz ultrasound biomicroscopy (UBM). Methods This study included 33 participants: 20 normal subjects (40 eyes), 2 patients with chronic lacrimal canaliculitis (4 eyes), 10 patients with chronic dacryocystitis (16 eyes), and 1 patient with lacrimal punctum atresia (2 eyes). All participants underwent 80-MHz UBM; disease-specific features were noted. Results On 80-MHz UBM of the lacrimal canaliculi (vertical section) in normal subjects, low echo of the lacrimal canalicular lumen and high echo of the lacrimal canalicular wall were observed. The uniform low echo near the wall was the mucosal epithelium. The outermost layer of medium-to-high echo was the subepithelial elastic fibrous layer. In the horizontal section, the lumen was continuous. Two linear high echoes parallel to the canalicular wall could be observed at the center of the lacrimal canaliculus, which were sometimes attached and sometimes separated. When separated, the center of the lacrimal canaliculus was a low echo area (lumen). Lacrimal canaliculitis (vertical section) showed obvious ectasia of the lacrimal canalicular lumen, with a high echo mass shadow, which might have been calculi, and uneven thickness of the mucosal epithelium with a slightly high echo shadow. In the horizontal section, the lumen varied in size with clear boundaries of medium and high echoes. The central linear high echoes of the lumen were absent, and the echoes of the mucosal epithelium were discontinuous. In chronic dacryocystitis, the lacrimal canalicular lumen was extensively enlarged, with continuous echoes and uniform thickness of the mucosal epithelium and homogeneous patches of slightly higher echoes. Lacrimal punctum atresia indicated that the lacrimal canaliculus existed in both eyes and its structure was normal. Conclusions The 80-MHz UBM is a new non-invasive technique that can be used for clear visualization of the fine structure of the lacrimal canaliculus, including the mucosal epithelium and subepithelial elastic fiber layer. The use of this approach will improve understanding of the hierarchical structure of the lacrimal canaliculi and provide a comprehensive basis for diagnosis, differential diagnosis, and treatment plan in patients with lacrimal passage diseases.
13
Tomita, Hideshi, Satoshi Yazaki, Kohji Kimura, Ken Watanabe, Kinya Hatakeyama, Yasuo Ono et Shigeyuki Echigo. « Acute recoil of stents used for the relief of stenotic great vessels in the setting of congenital cardiac disease ». Cardiology in the Young 13, no 6 (décembre 2003) : 519–25. http://dx.doi.org/10.1017/s1047951103001100.
Texte intégralRésumé :
We implanted either large or medium Palmaz stents, or a Palmaz Corinthian stent, in various stenotic vessels, such as the pulmonary arteries, pulmonary veins, aorta, or superior caval vein. Using angiograms, we measured the diameter of the stenotic vessel before or after the implantation, the minimal diameter of the lumen, the minimal diameter of the largest fully expanded balloon used to expand the stent, and the diameter immediately after withdrawal of the balloon.The minimal diameter of the fully expanded balloon, and the minimal diameter of the lumen subsequent to expansion, were 8.2 ± 2.4, and 7.7 ± 2.3 mm, giving an absolute recoil of 0.5 ± 0.4 mm, and a proportional recoil of 7 ± 4%. There was no significant difference in either the absolute or proportional recoil for any of the stents, or for any of the different stenotic vessels. The proportional recoil correlated linearly with the minimal diameter of the lumen prior to the procedure, and with the ratio of the stenosis to the balloon, while the diameter of the stenotic vessels, the minimal diameter of the largest fully expanded balloon, the proportional stenosis prior to the procedure, and the ratio of the balloon to the diameter of the stenotic vessel, had no significant correlation with proportional recoil. The proportional recoil exceeded more than one-tenth when the minimal diameter of the lumen prior to the dilation was less than 3 mm, or the ratio of the balloon to the stenosis was greater than 3.0.An absolute recoil of around 1 mm is common when a large or medium Palmaz, or a Palmaz Corinthian stent, is implanted in great vessels. Balloons with a diameter of approximately one-tenth greater than that of the adjacent vessel may be needed if the minimal diameter of the lumen is small prior to the procedure.
14
Schramm, U., G. Fricker, R. Wenger et D. S. Miller. « P-glycoprotein-mediated secretion of a fluorescent cyclosporin analogue by teleost renal proximal tubules ». American Journal of Physiology-Renal Physiology 268, no 1 (1 janvier 1995) : F46—F52. http://dx.doi.org/10.1152/ajprenal.1995.268.1.f46.
Texte intégralRésumé :
The transport of a fluorescent cyclosporin analogue was measured in killifish (Fundulus heteroclitus) proximal tubules by means of epifluorescence microscopy and digital image analysis. Renal cells rapidly accumulated the cyclosporin analogue from the medium and attained steady state within 60 min; luminal fluorescence increased over the first 60-90 min. At steady state, luminal fluorescence intensity was two to three times higher than cellular. Cellular fluorescence intensity was a linear function of medium substrate concentration and was not affected by any treatment used. In contrast, luminal fluorescence exhibited a saturable component as the medium concentration of the cyclosporin was increased. Secretion into the lumen was blocked by metabolic inhibitors, vanadate, other cyclosporins, such as cyclosporin A and cyclosporin G, and substrates for P-glycoprotein (verapamil, vinblastine, and quinine) but not by substrates for the renal organic anion or organic cation transport systems, such as p-aminohippurate or tetraethylammonium. The data are consistent with the fluorescent cyclosporin analogue entering proximal tubule cells by simple diffusion and then being pumped into the tubular lumen by P-glycoprotein.
15
Yilmaz, Berza Sen, Mihriban Kara, Elif Dilara Seker et Deniz Yenidünya. « Do we know how much force we apply with latex intermaxillary elastics ? » APOS Trends in Orthodontics 11 (5 octobre 2021) : 191–97. http://dx.doi.org/10.25259/apos_68_2021.
Texte intégralRésumé :
Objectives: The aim of our study was to evaluate the variation of the forces provided by different branded elastics and to compare the force diminution that occurs after 24-h of use in wet environment. Materials and Methods: Elastics from four different manufacturer (American Orthodontics [AO], USA; Dentaurum [DENT], Germany; Ormco, USA; RMO, USA) with 3/16-inch (4.8 mm) lumen diameter, and two different force degrees (medium/heavy) were included in the study with a total of eight groups of elastics. First force measurements were performed with 50 elastics of each group at various stretching distances; lumen diameter ×2 (9.52 mm), ×3 (14.28 mm), the average canine-first molar length (22.3 mm), and the canine-second molar length (38.7 mm) under room temperature and dry air conditions. In addition, ten the elastics from each group were stretched at 22.3 mm distance in a custom-made plate and kept in 37°C distilled water. Twenty-four hours later, the force measurements were repeated. Results: Regardless of the brand and type (medium-heavy), all the tested elastics showed variations in matter of generated forces at different stretching distances. The variation amount increased as the length of elongation increased. The lowest standard deviation values were observed for both medium and heavy DENT elastic groups. When stretched to 3 times of their lumen size, the medium and heavy elastics both produced either lower or higher forces compared to the levels of force indicated by the manufacturers. The closest mean force to the force level stated by the manufacturer was provided with medium AO (3.6 g difference) elastics and heavy RMO counterparts (7.9 g difference). A significant 20–23% reduction of force was observed in all brands, both in medium and heavy elastics after passing 24-h in aqueous environment. No significant difference was observed in matter of force degradation between groups for both medium and heavy elastics (P < 0.05). Conclusion: The forces exerted by intermaxillary elastics were not found to be standard and the force stated on the package is not always provided precisely. A significant force loss around 20% was observed with all the elastics after 24-h of use in wet environment at 37°C.
16
Yilmaz, Berza Sen, Mihriban Kara, Elif Dilara Seker et Deniz Yenidünya. « Do we know how much force we apply with latex intermaxillary elastics ? » APOS Trends in Orthodontics 11 (5 octobre 2021) : 191–97. http://dx.doi.org/10.25259/apos_68_2021.
Texte intégralRésumé :
Objectives: The aim of our study was to evaluate the variation of the forces provided by different branded elastics and to compare the force diminution that occurs after 24-h of use in wet environment. Materials and Methods: Elastics from four different manufacturer (American Orthodontics [AO], USA; Dentaurum [DENT], Germany; Ormco, USA; RMO, USA) with 3/16-inch (4.8 mm) lumen diameter, and two different force degrees (medium/heavy) were included in the study with a total of eight groups of elastics. First force measurements were performed with 50 elastics of each group at various stretching distances; lumen diameter ×2 (9.52 mm), ×3 (14.28 mm), the average canine-first molar length (22.3 mm), and the canine-second molar length (38.7 mm) under room temperature and dry air conditions. In addition, ten the elastics from each group were stretched at 22.3 mm distance in a custom-made plate and kept in 37°C distilled water. Twenty-four hours later, the force measurements were repeated. Results: Regardless of the brand and type (medium-heavy), all the tested elastics showed variations in matter of generated forces at different stretching distances. The variation amount increased as the length of elongation increased. The lowest standard deviation values were observed for both medium and heavy DENT elastic groups. When stretched to 3 times of their lumen size, the medium and heavy elastics both produced either lower or higher forces compared to the levels of force indicated by the manufacturers. The closest mean force to the force level stated by the manufacturer was provided with medium AO (3.6 g difference) elastics and heavy RMO counterparts (7.9 g difference). A significant 20–23% reduction of force was observed in all brands, both in medium and heavy elastics after passing 24-h in aqueous environment. No significant difference was observed in matter of force degradation between groups for both medium and heavy elastics (P < 0.05). Conclusion: The forces exerted by intermaxillary elastics were not found to be standard and the force stated on the package is not always provided precisely. A significant force loss around 20% was observed with all the elastics after 24-h of use in wet environment at 37°C.
17
Murakami, T., H. Oi, M. Hori, T. Kim, S. Takahashi, M. Matsushita, Y. Narumi et H. Nakamura. « CT Arterial Portography and CT Arteriography with a Triple-Lumen Balloon Catheter ». Acta Radiologica 38, no 4 (juillet 1997) : 553–57. http://dx.doi.org/10.1080/02841859709174386.
Texte intégralRésumé :
Purpose: To evaluate the usefulness of the triple-lumen balloon catheter in the serial performance of CT arterial portography (CT-AP) and CT arteriography (CT-A). Material and Methods: A combined CT-AP and CT-A examination of 58 patients was carried out in which a cobra-type triple-lumen balloon catheter was used. CT-AP was performed by injecting contrast medium either into the splenic artery through a side-hole in the catheter proximal to the balloon inflated in the common hepatic artery, or into the superior mesenteric artery through an end-hole in the catheter. Then CT-A was serially performed by delivering contrast medium either to the common hepatic artery or the proper hepatic artery from the end-hole, or to the accessory right hepatic artery through a side-hole proximal to the inflated balloon. Results: Sufficient CT-APs were obtained in 53 of the 58 patients (91%),.CT-A in 42 (72%), and both in 42 (72%). Incomplete CT-AP was due to technical failure or anatomical anomaly, as was incomplete CT-A. No complications were seen. Conclusion: The triple-lumen balloon catheter technique is useful and convenient in the serial performance of CT-AP and CT-A.
18
Kocer, Naci, Sedat G. Kandemirli, Daniel Ruijters, Michalis Mantatzis, Osman Kizilkilic et Civan Islak. « A technical note on intra-arterial cone-beam computed tomography for the evaluation of flow-diverter stents : Image quality differences between diluted and non-diluted contrast medium ». Interventional Neuroradiology 26, no 2 (25 novembre 2019) : 164–69. http://dx.doi.org/10.1177/1591019919890929.
Texte intégralRésumé :
Background Design of flow-diverter stents for flexibility, tractability, and low profile limits their radiopacity on conventional digital subtraction angiography. Cone-beam computed tomography (CBCT) offers higher spatial resolution for the evaluation of flow-diverter stents. However, CBCT requires optimal dilution and timing of contrast medium for simultaneous visualization of the stent, arterial lumen, and vessel wall. There are only limited data on the effects of different contrast dilutions on CBCT image quality in neurointerventional applications. Materials and methods In our institution, intra-arterial CBCTs were acquired during stent deployment and at follow-ups with 10% diluted contrast. We had recently started acquiring intra-arterial CBCTs with non-diluted contrast. Retrospective analysis of our flow-diverter data identified eight cases with different aneurysm locations who had intra-arterial CBCT with 10% diluted contrast immediately after flow-diverter stent deployment and with non-diluted contrast technique during follow-ups. For each case, the image quality between diluted and non-diluted contrast techniques was compared qualitatively by assessing stent visualization and quantitatively by plotting gray-scale intensity values along the vessel lumen. Results In two sets of CBCT images per each case, there was no substantial difference between diluted and non-diluted CBTC techniques for the evaluation of stent architecture and lumen opacification. Gray-scale intensity values perpendicular to the lumen revealed similar intensity values along the neighboring parenchyma, vessel wall, and lumen for the two different contrast techniques. Conclusion Intra-arterial CBCT angiography can be performed without contrast dilution and still achieve adequate image quality in certain cerebral aneurysms treated with flow diverter. The non-diluted contrast technique avoids the time loss during preparation of diluted contrast and installation of diluted contrast to the injector in angiography suites with a single power injector.
19
Harapko, Tatyana, et Andrew Holovatsky. « THE FEATURES OF ARTERIAL THYMUSATNALBUPHINEACTION ». EUREKA : Health Sciences 2 (31 mars 2016) : 30–37. http://dx.doi.org/10.21303/2504-5679.2016.00091.
Texte intégralRésumé :
The article presents and analyzes the results of the pilot study, at which opioid nalbuphine was daily administered in white rats-males of reproductive age (1,5–3,5 – month) for six weeks and one week after discontinuation of therapy. The drug “nalbuphine” was injected intraperitoneally daily 1 per day over 42 days. The data were compared with a control group of intact animals. The study was conducted on 52 animals, which were divided into eight groups. Morphometric study was performed using a system of visual analysis of histological preparations. Dynamics of changes in the external and internal diameters of medium caliber arteries thymus, media and lumen area, Vohenvorta ratio was studied. The increase of the external diameter and reduction of the internal diameter of the medium caliber arteries, increase of the area of media, increase of the area of the lumen, increase of the Vohenvortaratio.The blood vessels are dilated, gaps filled elements of the blood vessels around the swelling, the process of vascular sclerosis.
20
Jutabha, Promsuk, Chaivat Toskulkao et Varanuj Chatsudthipong. « Effect of stevioside on PAH transport by isolated perfused rabbit renal proximal tubule ». Canadian Journal of Physiology and Pharmacology 78, no 9 (1 septembre 2000) : 737–44. http://dx.doi.org/10.1139/y00-051.
Texte intégralRésumé :
Stevioside, a non-caloric sweetening agent, is used as a sugar substitute. An influence of stevioside on renal function has been suggested, but little is known about its effect on tubular function. Therefore, the present study was designed to explore the direct effect of stevioside on transepithelial transport of p-aminohippurate (PAH) in isolated S2 segments of rabbit proximal renal tubules using in vitro microperfusion. Addition of stevioside at a concentration of 0.45 mM to either the tubular lumen, bathing medium, or both at the same time had no effect on transepithelial transport of PAH. Similarly, a concentration of 0.70 mM (maximum solubility in the buffer) when present in the lumen, had no effect on PAH transport. However, this concentration in the bathing medium inhibited PAH transport significantly by about 25-35%. The inhibitory effect of stevioside was gradually abolished after it was removed from the bath. Addition of 0.70 mM stevioside to both lumen and bathing medium at the same time produced no added inhibitory effect. Stevioside at this concentration has no effect on Na+/K+-ATPase activity as well as cell ATP content. These findings suggest that stevioside, at a pharmacological concentration of 0.70 mM, inhibits transepithelial transport of PAH by interfering with the basolateral entry step, the rate-limiting step for transepithelial transport. The lack of effect of stevioside on transepithelial transport of PAH on the luminal side and its reversible inhibitory effect on the basolateral side indicate that stevioside does not permanently change PAH transport and should not harm renal tubular function at normal human intake levels.Key words: stevioside, p-aminohippurate, renal proximal tubule.
21
Raees, Muhammad Aanish, Paul V. Dubar et David P. Bichell. « A Medium-Term Venous Access Alternative for Infants Undergoing Congenital Heart Surgery ». World Journal for Pediatric and Congenital Heart Surgery 9, no 1 (janvier 2018) : 91–94. http://dx.doi.org/10.1177/2150135117738008.
Texte intégralRésumé :
We describe a strategy aimed at maximizing the safety and minimizing the thrombogenicity of central venous lines for neonates with congenital heart defects. Our method involves the use of a tunneled technique to place a 4.2 Fr single-lumen (Broviac) catheter in the subpericardial space, with minimal intravascular course and a tip placed in the lower right atrium. Using this technique, we potentially eliminated the requirement for percutaneous placement of central venous lines postoperatively as well as potentially decreased the risk of intrapericardial bleeding associated with transthoracic lines.
22
Lucius, R. W., I. D. Waddell, A. Burchell et R. C. Nordlie. « The hepatic glucose-6-phosphatase system in Ehrlich-ascites-tumour-bearing mice ». Biochemical Journal 290, no 3 (15 mars 1993) : 907–11. http://dx.doi.org/10.1042/bj2900907.
Texte intégralRésumé :
To examine the effects of the presence of Ehrlich ascites tumours on both the catalytic unit and the substrate/product translocase components of the glucose-6-phosphatase system in vivo, we isolated microsomes from the livers of control and tumour-bearing mice. Samples were analysed immunochemically for the quantity of catalytic unit, stabilizing protein and translocases T2 and T3 proteins. In comparison experiments, a variety of kinetic studies were performed. The most striking findings in tumour-bearing mice were: a 2.5-fold increase in the quantity of translocase T2 protein; increases in the Km and Vmax. for glucose 6-phosphate phosphohydrolase; and a decrease in the Km value for carbamoyl phosphate (carbamoyl-P) of carbamoyl-P:glucose phosphotransferase, all with intact microsomes. The percentage latency at Vmax. decreased for PPi phosphohydrolase and for glucose 6-phosphate phosphohydrolase, but was unaffected for carbamoyl-P:glucose phosphotransferase. These observations support a tumour-related increase in translocase T2 capacity in vivo, as it transports Pi from the microsomal lumen to the medium and carbamoyl-P or PPi from the medium to the microsomal lumen.
23
Brokl, O. H., E. J. Braun et W. H. Dantzler. « Transport of PAH, urate, TEA, and fluid by isolated perfused and nonperfused avian renal proximal tubules ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 266, no 4 (1 avril 1994) : R1085—R1094. http://dx.doi.org/10.1152/ajpregu.1994.266.4.r1085.
Texte intégralRésumé :
Transport of organic anions [p-aminohippurate (PAH) and urate] and organic cations [tetraethylammonium (TEA)] and reabsorption of fluid were studied for the first time in individual renal proximal tubules isolated from avian kidneys. In isolated nonperfused tubules, PAH and urate uptake occurred against electrochemical gradients, whereas TEA uptake appeared to result from the electrical gradient. Radiolabeled PAH uptake and radiolabeled urate uptake were inhibited to an equal extent by high concentrations of unlabeled PAH and probenecid, suggesting that they might share the same transport system. However, the rate of uptake of radiolabeled PAH was significantly stimulated by preloading with alpha-ketoglutarate (alpha-KG), suggesting PAH/alpha-KG countertransport as in mammals and reptiles, whereas uptake of radiolabeled urate was not clearly stimulated. In isolated perfused tubules, net fluid reabsorption averaged approximately 2 nl.min-1.mm-1 and was inhibited by ouabain with or without bicarbonate in the perfusate and bathing medium. In these perfused tubules, the unidirectional bath-to-lumen fluxes of PAH and urate exceeded the unidirectional lumen-to-bath fluxes, indicating net secretion of both compounds. During the bath-to-lumen fluxes the uptake across the basolateral membrane was against an electrochemical gradient for both compounds. However, for PAH the steady-state intracellular concentration was about half that observed in nonperfused tubules, as generally expected during net secretion, whereas for urate the steady-state intracellular concentration was about twice that observed in nonperfused tubules, suggesting stimulation of uptake during net secretion. During the PAH lumen-to-bath flux, the steady-state intracellular concentration was significantly above that in the perfusate, suggesting that this flux involved transport into the cells from the lumen against an electrochemical gradient. However, during the urate lumen-to-bath flux, there was no urate in the cells, suggesting that this flux, as in reptiles, occurred by a paracellular route.
24
Kassab, Ghassan S., Eugen R. Lontis, Arne Hørlyck et Hans Gregersen. « Novel method for measurement of medium size arterial lumen area with an impedance catheter : in vivo validation ». American Journal of Physiology-Heart and Circulatory Physiology 288, no 4 (avril 2005) : H2014—H2020. http://dx.doi.org/10.1152/ajpheart.00508.2004.
Texte intégralRésumé :
There is no doubt that the transformation of a cardiac catheter into a conductance catheter that allows reliable and accurate assessment of lumen cross-sectional area (CSA) will provide a powerful diagnostic and treatment tool for the invasive cardiologist. The objective of this study was to develop a method based on the impedance catheter that allows accurate and reproducible measurements of CSA for medium size vessels (e.g., coronary, femoral, and carotid arteries). Two solutions of NaCl (0.5% and 1.5%) with known conductivities were injected directly into the lumen of the artery in eight swine. We showed that the CSA can be determined analytically from two Ohm's law-type algebraic equations that account for the parallel conductance of the current into the surrounding tissue. Excellent agreement was found between the conductance catheter with the proposed two-injection method and B-mode ultrasound (US). The root mean square error for the impedance measurements was 4.8% of the mean US diameter. The repeatability of the technique was assessed with duplicate measurements. The mean of the difference between the two measurements was nearly zero, and the repeatability coefficient was within 2.4% of the mean of the two measurements. The validated method was used to assess the degree of acute vasodilatation of the vessel in response to flow overload.
25
Danielsen, E. M., G. H. Hansen et M. D. Poulsen. « Apical secretion of apolipoproteins from enterocytes. » Journal of Cell Biology 120, no 6 (15 mars 1993) : 1347–56. http://dx.doi.org/10.1083/jcb.120.6.1347.
Texte intégralRésumé :
Synthesis and secretion of apolipoproteins in pig small intestine was studied by pulse-chase labeling of jejunal segments, kept in organ culture. Apo A-1 and apo B-48 were the two major proteins released, constituting 25 and 10%, respectively, of the total amount of labeled protein in the mucosal-side medium where they appeared with a t1/2 of 50-60 min. Using tissue from fasting animals, > 85% of newly synthesized apo A-1 and about one third of apo B-48 was released to the mucosal-side medium. Newly synthesized apolipoprotein that remained associated with the intestinal segment accumulated in the soluble fraction, suggesting a basolateral secretion into the intercellular space, and both this accumulation and the release to the medium was prevented by culture at 20 degrees C. The specific radioactivity of apo A-1 and apo B-48 released to the medium was significantly higher than that of the corresponding apolipoproteins remaining associated with the intestinal tissue. Furthermore, during culture periods of up to 5 h, the enterocytes and their tight junctions largely remained intact as evidenced by the inaccessibility of the nonpermeable surface marker Ruthenium red. We therefore propose that enterocytes release most of their newly made free apo A-1 and a significant portion of apo B-48 by exocytosis via the brush border membrane into the intestinal lumen. Fat absorption reduced apolipoprotein secretion to the medium and induced the formation of chylomicrons, containing apo A-1 at their surface, as evidenced by immunogold electron microscopy. The chylomicrons were localized in the Golgi complex and near the basolateral plasma membrane, but not in the apical region of the enterocytes, indicating that only free apolipoproteins are secreted to the intestinal lumen.
26
Nakaji, Kosuke, Keiichi Itatani, Nagara Tamaki, Hiroko Morichi, Naohiko Nakanishi, Masao Takigami, Masaaki Yamagishi, Hitoshi Yaku et Kei Yamada. « Assessment of biventricular hemodynamics and energy dynamics using lumen-tracking 4D flow MRI without contrast medium ». Journal of Cardiology 78, no 1 (juillet 2021) : 79–87. http://dx.doi.org/10.1016/j.jjcc.2021.01.004.
Texte intégral
27
Sartoretti, Thomas, Matthias Eberhard, Jan Hendrik Rüschoff, Hubertus Pietsch, Gregor Jost, Tristan Nowak, Bernhard Schmidt, Thomas Flohr, André Euler et Hatem Alkadhi. « Photon-counting CT with tungsten as contrast medium : Experimental evidence of vessel lumen and plaque visualization ». Atherosclerosis 310 (octobre 2020) : 11–16. http://dx.doi.org/10.1016/j.atherosclerosis.2020.07.023.
Texte intégral
28
Todua, F. I., D. G. Gachechiladze, D. K. Miminoshvili et K. V. Lomidze. « Correlation of the Computed Tomography Angiography Data with the Clinical Neurological Presentation in Case of Small Degree Stenosis of Internal Carotid Arteries ». Medical Visualization, no 4 (28 août 2017) : 113–22. http://dx.doi.org/10.24835/1607-0763-2017-4-113-122.
Texte intégralRésumé :
Purpose. To carry out the correlation of the lumen structure of internal carotid artery (ICA) to the neurological symptoms in patients with small-intermediate (30–69%) degree stenosis based on multislice computed tomography angiography (MSCTA) data; evaluate potential embologenicity of atherosclerotic plaques in patients with small-intermediate stenosis of ICA.Materials and methods. The data of 49 patients with 30–69% stenosis of ICA were evaluated, 43 (87.8%) men and 6 (12.2%) women; age varied from 51 to 78 years (medium age 59.8 ± 12.2 years). Depending on neurological presentation, patients were divided into 4 groups, according to academician A.V. Pokrovsky classification of cerebro-vascular insufficiency (1979). All patients underwent CTA on the apparatus Toshiba Aquilion One. The CTA data was transferred to the Vitrea workstation for the analysis. Following 3D-recontractions were used: MIP –Maximal Intensity projection, MPR – Multi-Planar Reconstruction, SSD – Shaded Surface Display. Along with estimation of the lumen shape, attention was paid to the presence of ulcerations, which appeared as the indentation of the contour and/or as a plaque with multiple hollows or cavernous appearance.Results. Mean stenosis degree appeared to be 59.7% in all 49 patients (stenosis index varied from 36% to 67%). In 27 asymptomatic patients mean value of stenosis was 57.8%, in case of discirculatory encephalopathy – 59.6%, in case of transient ischemic attack (TIA) – 60.1%, and in 2 patients with stroke – 62.4%. Based on the analysis of the CTA in 23 (46.9%) cases plaque surface was irregular (Type II and II ulceration prevailed). Type I ulcerations were noted in 5 (10.2%), type II –in 11 (22.4%) and type III – in 7 (14.2%) cases. CTA images showed circular lumen in 15 (30.6%) patient, elliptic lumen in 19 (38.8%) patients, semicircular lumen was seen in 65(12.2%) cases and multilobular – in 9 (18.3%) cases. Correlation of the lumen structure with the clinical presentation showed prevalence of cases with irregular lumen contours in patients with symptomatic cerebral ischemia: impairment of cerebral circulation was seen in 1 out of 15 (6.7) circular narrowings, in 1 out of 19 (5.2%) elliptic narrowings, in 5 out of 9 (55.6%) multilobular and in 2 out of 6 (33.3%) semicircular narrowings.Conclusion. Asymmetric lumen of ICA revealed by MSCTA with the bigger probability is connected to the presence of ipsilateral symptomatic ischemia, including transient amavrosis, TIA and ischemic stroke. Our study showed, that evaluation of ICA lumen morphology makes possible to reveal patients with increased risk of focal disturbance of brain circulation in case of small-intermediate degree (30–69%) of stenosis.
29
Thorvinger, B., et U. Albrechtsson. « Spontaneous Resolution of a Descending Aortic Dissection ». Acta Radiologica 30, no 3 (mai 1989) : 305–6. http://dx.doi.org/10.1177/028418518903000316.
Texte intégralRésumé :
The natural history of an aortic dissection is either endothelialization of the false lumen forming a so-called double-barrelled aorta, or thrombosis of the sack leading to fibrosis and scarring. Complete healing of an aortic dissection is extremely rare, and has to our knowledge only been reported once in vivo. Here we report a second case of spontaneous resolution of an aortic dissection, disclosed by contrast medium enhanced computed tomography.
30
Capisizu, Adriana S., Dragoș Cuzino et Silviu M. Stanciu. « The Role of Coronary CT Angiography in the Management of Patients with Coronary Atherosclerotic Diseas ». Romanian Journal of Military Medicine 126, no 2 (1 mai 2023) : 160–65. http://dx.doi.org/10.55453/rjmm.2023.126.2.6.
Texte intégralRésumé :
"Coronary CT angiography is a non-invasive method of analyzing the coronary lumen through which the atheromatous bur-den can be evaluated, with the analysis of the type of plaque (soft, calcified, mixed) and the impact on the arterial lumen (stenosis, occlusion). The anatomical evaluation by coronary CT is indicated in symptomatic patients with low and medium risk factors for coronary atherosclerotic disease, in those with inconclusive laboratory and EKG results, patients with un-certain stress test results, in the evaluation of coronary grafts and intrastent stenoses. Depending on the result of the angiography, the severity of the stenosis and the management of the patient are established. In the case of mild and medium stenoses, risk factors management and drug treatment are recommended. For severe stenoses, patients are referred for interventional coronary angiography or functional evaluation. Coronary CT angiography increases the certainty of coronary atherosclerotic disease diagnosis. It has a superior discriminative capacity of plaques with low attenuation, the main predictor of myocardial infarction, with almost five-fold higher risk. Coronary CT angiography increases the adaptation of medication, and the inclusion of statin therapy decreases the risk of fatal and nonfatal myocardial infarction at 5 years and increases the quality of life "
31
Altenbernd, J., S. Zimmer, L. Andrae, B. Labonte, J. Gruber, H. Beier, M. Abdulgader, M. Buechter, M. Forsting et J. Theysohn. « High volume retrograde portography for better discrimination of the portal vein during TIPS procedure ». Acta Radiologica Open 11, no 9 (septembre 2022) : 205846012211284. http://dx.doi.org/10.1177/20584601221128405.
Texte intégralRésumé :
Background: Imaging of the portal vein prior to puncture for TIPS is essential. Purpose: With this study, we examined a modified retrograde portography with regard to the reliable representation of the portal vein. Material and Methods: Prospective evaluation of 65 TIPS interventions with regard to the delimitation of the portal vein and the exact parameters of retrograde portography such as catheter diameter and contrast medium volume per injection. Results: Retrograde portographies with a large-lumen catheter (10 F) and a large contrast medium volume (40 mL) were performed in 35/63 patients with significantly better delineation of the portal vein than when using 5 F catheters with 10 mL contrast medium. Conclusion: The so-called high volume retrograde portography leads to better delimitation of the portal vein during TIPS application.
32
Soriano, J. V., M. S. Pepper, T. Nakamura, L. Orci et R. Montesano. « Hepatocyte growth factor stimulates extensive development of branching duct-like structures by cloned mammary gland epithelial cells ». Journal of Cell Science 108, no 2 (1 février 1995) : 413–30. http://dx.doi.org/10.1242/jcs.108.2.413.
Texte intégralRésumé :
Although epithelial-mesenchymal (stromal) interactions are thought to play an important role in embryonic and postnatal development of the mammary gland, the underlying mechanisms are still poorly understood. To address this issue, we assessed the effect of fibroblast-derived diffusible factors on the growth and morphogenetic properties of a clonally derived subpopulation (clone TAC-2) of normal murine mammary gland (NMuMG) epithelial cells embedded in collagen gels. Under control conditions, TAC-2 mammary gland epithelial cells suspended within collagen gels formed either irregularly shaped cell aggregates or short branching cord-like structures. Addition of conditioned medium from Swiss 3T3 or MRC-5 fibroblasts dramatically stimulated cord formation by TAC-2 cells, resulting in the development of an extensive, highly arborized system of duct-like structures, which in appropriate sections were seen to contain a central lumen. The effect of fibroblast conditioned medium was completely abrogated by antibodies against hepatocyte growth factor (also known as scatter factor), a fibroblast-derived polypeptide that we have previously shown induces tubulogenesis by Madin-Darby canine kidney epithelial cells. Addition of exogenous recombinant human hepatocyte growth factor to collagen gel cultures of TAC-2 cells mimicked the tubulogenic activity of fibroblast conditioned medium by stimulating formation of branching duct-like structures in a dose-dependent manner, with a maximal 77-fold increase in cord length at 20 ng/ml. The effect of either fibroblast conditioned medium or hepatocyte growth factor was markedly potentiated by the simultaneous addition of hydrocortisone (1 microgram/ml), which also enhanced lumen formation. These results demonstrate that hepatocyte growth factor promotes the formation of branching duct-like structures by mammary gland epithelial cells in vitro, and suggest that it may act as a mediator of the inducing effect of mesenchyme (or stroma) on mammary gland development.
33
Nguyen, Thi Phuong Thao, Doan Quoc Anh Nguyen, Miroslav Voznak et Van Tho Le. « Improving Lighting Performance of High Color Temperature White LED Packages Using (La,Ce,Tb) PO4:Ce:Tb Phosphor ». Journal of Advanced Engineering and Computation 1, no 2 (30 novembre 2017) : 87. http://dx.doi.org/10.25073/jaec.201712.81.
Texte intégralRésumé :
Enhancement of the color uniformity, the lumen output of the multi-chip white LED lamps (MCW-LEDs) at high color correlated temperature is a big challenge for researchers. However, an innovative LED lamp designed with a phosphor compounding, which combines (La,Ce,Tb) PO4:Ce:Tb (LaTb) green phosphor with YAG: CE yellow phosphor, is proposed as an optimal solution to this requirement. Index, using LaTb green phosphor into MCWLEDs could bring a superior optical performance for MCW-LEDs. It is found that the lumen output of this new MCW-LED at a high color temperature of 8500 K significantly improves up to 1600 lm compared to MCW-LEDs without LaTb phosphor. The simulation results demonstrated that the CCT deviation sharply decreases from 9000 to 1000 at the LaTb concentration range from 0 to 1.8 %, while the Color Rendering Index ability (CRI) and the Color Quality Scale (CQS) slightly decrease. To obtain the highest lumen output and the best color uniformity, the particle size range within 6 - 8 µm should be suggested. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
34
Dedkov, Eduard I. « Large- and Medium-sized Arteries Remaining in Transmural Scar Distal to Permanent Coronary Ligation Undergo Neointimal Hyperplasia and Inward Remodeling ». Journal of Histochemistry & ; Cytochemistry 69, no 5 (22 mars 2021) : 321–38. http://dx.doi.org/10.1369/00221554211004297.
Texte intégralRésumé :
This study aimed to investigate the structural integrity and dynamic changes in chronically occluded residual arteries found in post–myocardial infarction (MI) scar. A transmural MI was induced in middle-aged, male Sprague-Dawley rats by left coronary artery ligation. The rats were euthanized 3 days and 1, 2, 4, 8, and 12 weeks after MI, and their hearts were processed into paraffin for histology, immunohistochemistry, and quantitative morphometry. It has been found that large- and medium-sized arteries were able to survive inside the transmural scars for 12 post-MI weeks. Furthermore, most residual arteries preserved their structural integrity for up to 2 weeks post-MI, but gradually all disused vessels had undergone neointimal hyperplasia and inward remodeling at later time periods. In addition, the replacement of vascular smooth muscle cells in the wall of residual arteries by extracellular matrix components led to a disruption of the vessel integrity and progressive obliteration of their lumen between 4 and 12 post-MI weeks. Taken together, this study demonstrate that residual arteries in post-infarcted region were capable of maintaining their structural integrity, including the patent lumen, during two post-MI weeks, suggesting that during this period they can be used as potential conduits for conceivable reflow of arterial blood within the scarred region of the heart
35
Kudris, I. V. « Echocardiographic findings in pulmonary immaturity in premature infants ». Kazan medical journal 82, no 6 (15 décembre 2001) : 455. http://dx.doi.org/10.17816/kazmj84428.
Texte intégralRésumé :
The main cause of morbidity in preterm and premature infants remains pulmonary pathology. Among the features of the bronchopulmonary structures of premature and immature preterm infants is a lag in the development of the arterial network from the venous one. Small and medium arteries have narrow lumen and thick muscle mass. When the lungs are unfolded, an obstacle is created for rapid blood flow in the small circle of circulation, which results in delayed unfolding of the alveoli.
36
Kabakov, D. G., A. Yu Zaytsev, M. A. Vyzhigina, K. V. Dubrovin, G. A. Kazaryan et D. I. Novikov. « Providing one-lung ventilation in posttracheostomic tracheal stenosis for thoracoscopic plastic of the right diaphragm dome ». Messenger of ANESTHESIOLOGY AND RESUSCITATION 18, no 5 (6 novembre 2021) : 76–81. http://dx.doi.org/10.21292/2078-5658-2021-18-5-76-81.
Texte intégralRésumé :
The article is devoted to the consideration of a clinical case of providing artifcial one-lung ventilation for performing thoracoscopic plastic of the right dome of the diaphragm in a patient with grade 3 posttracheostomy cicatricial tracheal stenosis. The patient is presented after a new coronavirus infection COVID-19 from 2020, prolonged mechanical ventilation through a tracheostomy tube (74 days), the development of medium thoracic cicatricial tracheal stenosis of grade 3 (the lumen of the narrowest part of the trachea is 4 mm) after decannulation and the development of relaxation of the right dome of the diaphragm (according to CT data, the dome is located at the level of the IV intercostal space). The frst stage under conditions of combined general anesthesia and high-frequency ventilation of the lungs was performed to restore the lumen of the trachea by bougienage of the stenosis area with tubes of a rigid endoscope under the control of a fberoptic bronchoscope with further nasotracheal intubation with a thermoplastic single-lumen endotracheal tube with a diameter of 8.0 with a cuff. At the second stage, during thoracoscopic plastic of the right dome of the diaphragm, to provide artifcial one-lung ventilation, a bronchial blocker was used, introduced through the same endotracheal tube into the right main bronchus under the control of a fberoptic bronchoscope.
37
Miller, D. S. « Daunomycin secretion by killfish renal proximal tubules ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 269, no 2 (1 août 1995) : R370—R379. http://dx.doi.org/10.1152/ajpregu.1995.269.2.r370.
Texte intégralRésumé :
Epifluorescence microscopy and video-image analysis were used to measure the uptake of the fluorescent anthracycline daunomycin by intact killifish renal proximal tubules. When tubules were incubated in medium containing 2-5 microM daunomycin, the drug accumulated in the cells and the tubular lumen. At steady state, luminal fluorescence was two to three times greater than cellular fluorescence. Luminal accumulation of daunomycin was reduced when tubules were exposed to the multidrug-resistance (MDR) transporter modifiers verapamil and cyclosporin A (CSA), but not tetraethylammonium (TEA), a model substrate for the renal organic cation transport system. NaCN and vanadate reduced luminal drug accumulation. In contrast, cellular daunomycin accumulation was not affected by verapamil, CSA, TEA, or vanadate and was only slightly reduced by NaCN. When the pH of the buffer solution was decreased from 8.25 to 7.25, luminal, but not cellular, accumulation of daunomycin was again reduced by CSA; however, TEA now reduced cellular and luminal accumulation. These findings are consistent with daunomycin being actively secreted in killifish proximal tubule by two mechanisms. At pH 8.25, daunomycin crossed the basolateral membrane by simple diffusion and was secreted into the tubular lumen by the MDR transporter. At pH 7.25, daunomycin was transported across the basolateral membrane by simple diffusion and carrier-mediated uptake on the organic cation transporter and was secreted into the lumen by the MDR transporter and the organic cation/H+ exchanger.
38
Dantzler, W. H., et K. K. Evans. « Effect of alpha-KG in lumen on PAH transport by isolated perfused rabbit renal proximal tubules ». American Journal of Physiology-Renal Physiology 271, no 3 (1 septembre 1996) : F521—F526. http://dx.doi.org/10.1152/ajprenal.1996.271.3.f521.
Texte intégralRésumé :
To determine whether dicarboxylate taken up at the luminal membrane could function in the p-aminohippurate (PAH) countertransport at the basolateral membrane, we examined the effect of adding alpha-ketoglutarate (alpha-KG) or glutarate (a nonmetabolized dicarboxylate that is countertransported for PAH at the basolateral membrane) to the luminal perfusate on net secretion of radiolabeled PAH in isolated perfused S2 segments of rabbit proximal tubules. Addition of 100 microM alpha-KG or glutarate to the luminal perfusate in tubules perfused and bathed with HEPES-buffered medium (in the absence of bicarbonate, glycine, lactate, malate, and citrate) produced a reversible twofold stimulation of net PAH transepithelial secretion. Addition of 4 mM LiCl (an inhibitor of Na-dicarboxylate transport that does not directly affect PAH transport) to the luminal perfusate along with alpha-KG eliminated stimulation of net PAH secretion. Addition of 100 microM or 1 mM alpha-KG or glutarate to the luminal perfusate in tubules perfused and bathed with bicarbonate-buffered medium containing glycine, lactate, malate, and citrate had no effect on net PAH transport from bath to lumen. These data indicate that alpha-KG (or glutarate) that enters the tubule cells via the luminal Na-dicarboxylate cotransporter can stimulate net PAH secretion, apparently via countertransport at the basolateral membrane, but only when tubules are not in an optimal metabolic state to produce intracellular alpha-KG.
39
Matsumoto, Kengo, Toshikazu Saijo, Hideyuki Kuyama, Shoji Asari et Akira Nishimoto. « Hemifacial spasm caused by a spontaneous dissecting aneurysm of the vertebral artery ». Journal of Neurosurgery 74, no 4 (avril 1991) : 650–52. http://dx.doi.org/10.3171/jns.1991.74.4.0650.
Texte intégralRésumé :
✓ The authors describe the first reported case of dissecting aneurysm presenting with hemifacial spasm. The patient was a 58-year-old woman with left hemifacial spasm of 2 years' duration. Cranial nerve examination was otherwise normal and no other clinical symptoms were observed. Vertebral angiography revealed a fusiform enlargement of the left vertebral artery and contrast medium remaining in the intramural false lumen in the venous phase. Microvascular decompression of the facial nerve with wrapping of the aneurysm resulted in complete relief of the hemifacial spasm.
40
Irving, R. M., N. S. Jones, M. A. Hall-Craggs et B. Kendall. « CT and MR imaging in lateral sinus thrombosis ». Journal of Laryngology & ; Otology 105, no 8 (août 1991) : 693–95. http://dx.doi.org/10.1017/s0022215100117050.
Texte intégralRésumé :
AbstactEstablishing a pre-operative diagnosis of lateral sinus thrombosis can be difficult, as the clinical features are non-specific and laboratory tests unhelpful. CT maydemonstrate abnormal high density of the lumen of the sinus, which does not enhance afterintravenous contrast medium. Enhancement of the dura surrounding the sinus may be prominent, causing the ‘empty triangle’ or ‘delta sign’ which may suggest the diagnosis. Magnetic resonance (MR) imaging may show both lack of flow and abnormal signal from the sinus, thus providing definitive evidence of thrombosis.
41
Tanaka, Toshiyuki, Hideo Akiyoshi, Keiichiro Mie, Hitoshi Shimazaki et Fumihito Ohashi. « Drip infusion cholangiography with CT in cats ». Journal of Feline Medicine and Surgery 20, no 12 (1 décembre 2017) : 1173–76. http://dx.doi.org/10.1177/1098612x17738615.
Texte intégralRésumé :
Objectives Ultrasonography can detect extrahepatic biliary obstructions. However, visualisation of part of the bile duct using ultrasonography can be technically difficult if there is overlying bowel gas. This study investigated the safety and value of drip infusion cholangiography with computed tomography (DIC-CT) in the visualisation of the bile duct in healthy cats and extrahepatic biliary obstruction in cats with cholelithiasis. Methods DIC-CT was performed in three healthy cats and two cats with cholelithiasis. Meglumine iotroxate was administered by intravenous drip infusion over 30 mins. The attenuation value was measured perpendicular to the lumen by a region of interest covering about 50% of the area of the lumen. Results The bile ducts were visualised successfully with DIC-CT in all healthy cats without any significant adverse events. The attenuation value of the contrast medium was 271 ± 37 HU. In the two cats with cholelithiasis, the presence or absence of extrahepatic biliary obstruction was determined using DIC-CT without any significant adverse events. The attenuation value of cholelithiasis in the cat with an extrahepatic biliary obstruction was 933 ± 119 HU. In the cat with no extrahepatic biliary obstruction, the attenuation value of the contrast medium was 249 ± 53 HU and the attenuation value of cholelithiasis was 167 ± 28 HU. Conclusions and relevance DIC-CT visualises bile ducts and detects obstructive biliary disease without significant adverse events. Therefore, it appears to be a safe procedure for visualisation of the bile duct in cats.
42
Barrera-Zarate, J. A., B. A. Paiva, D. P. Ferreira, F. S. Alves, J. P. H. Sato et R. M. C. Guedes. « Barium sulphate aspiration pneumonia in a cat with megaesophagus and dextroposition of the aortic arch : case report ». Arquivo Brasileiro de Medicina Veterinária e Zootecnia 70, no 5 (octobre 2018) : 1453–58. http://dx.doi.org/10.1590/1678-4162-10059.
Texte intégralRésumé :
ABSTRACT A six-month-old female cat suffered aspiration of an abundant amount of barium sulfate during a radiographic procedure for the diagnosis of megaesophagus. Latero-lateral contrast radiography revealed severe dilation of the thoracic esophagus cranial to the base of the heart. Persistence of the right aortic arch was suspected and later confirmed during corrective surgery. Accumulation of barium sulfate, used as a contrast agent, was clearly observed in the lumen of the bronchi, bronchioles, and alveoli in the radiographic image. Days after the surgery, the animal developed severe respiratory distress, which resulted in death. Cytology results and histology analysis using polarized light demonstrated that the lumen of bronchi, bronchioles, and alveoli exhibited evident histiocytic infiltration with cytoplasm filled by abundant amorphous refractive granular material consistent with barium sulfate. In this report, we describe the anatomical, cytological, histopathological (using polarized light), and x-ray findings of a case of barium sulfate aspiration pneumonia in a cat resulting from the use of this contrast medium for the diagnosis of megaesophagus secondary to persistent right aortic arch.
43
Takahashi, Y., C. Goto et K. K. Kita. « Ultrastructural study of Trichinella spiralis with emphasis on adult male reproductive organs ». Journal of Helminthology 68, no 4 (décembre 1994) : 353–58. http://dx.doi.org/10.1017/s0022149x00001632.
Texte intégralRésumé :
AbstractThe ultrastructure of the reproductive system of adult male Trichinella spiralis has been examined, particularly to assist in recent advances such as the localization of target antigens of protective immunity and the mode of immune attack. The male reproductive system consists of a single tube with a hairpin-like bend, composed of a basal lamina, epithelial cells, rachis, circumferential and constrictor muscles, and germinal cells. The organs were surrounded by basal lamina and haemolymph. Germinal cells in different stages of maturation were found on the wall of the testis along its entire length. As the maturation of germinal cells proceeded, the cells moved towards the lumen of the testis. The germinal cells had a row of vesicles (cup-shaped structures) at the cell periphery. The mature sperm, lacking flagella and an acrosome, were stored in the seminal vesicle. The cytoplasm of the epithelial cells of the seminal vesicle and ejaculatory duct was filled with distended rough endoplasmic reticulum (rER) and exocrine granules which appeared homogenous and of medium electron density. The granules appeared to discharge to the lumen.
44
Parfenov, A. I., et L. M. Krums. « Protein-losing enteropathy ». Terapevticheskii arkhiv 89, no 2 (15 février 2017) : 4–9. http://dx.doi.org/10.17116/terarkh20178924-9.
Texte intégralRésumé :
Protein-losing enteropathy (PLE) is a rare complication of intestinal diseases. Its main manifestation is hypoproteinemic edema. The diagnosis of PLE is based on the verification of protein loss into the intestinal lumen, by determining fecal α1-antitrypsin concentration and clearance. The localization of the affected colonic segment is clarified using radiologic and endoscopic techniques. The mainstay of treatment for PLE is a fat-free diet enriched with medium-chain triglycerides. Surgical resection of the affected segment of the colon may be the treatment of choice for severe hypoproteinemia resistant to drug therapy.
45
Ibrahim, Norhayati, et Hasmawi Khalid. « Charphy Impact of Medium Molecular Weight Phenol Formaldehyde (MMwPF) Plywood ». Journal of Advanced Research in Applied Sciences and Engineering Technology 18, no 1 (31 mars 2020) : 24–30. http://dx.doi.org/10.37934/araset.18.1.2430.
Texte intégralRésumé :
Plywood is a wood product frequently utilized in building as part of concrete formwork systems. In the concreting process, plywood formwork needs to be strongly made to withstand the pressure subjected by the wet concrete as well as the impact. To reduce the dependency on solid timber as plywood, oil palm stem offers alternative materials. There are four main weaknesses of oil palm stem (OPS) as a material for plywood manufacturing; high variations in density and moisture content (MC), high water absorption and high surface roughness. Therefore, this study modified the drying and treatment process of OPS veneer. The veneer was predried by using roller presser for removing a large amount of water and later treated with medium molecular weight phenolformaldehyde (MMwPF) to bond together parenchyma tissue, cell wall, and a lumen for much uniform density and better surface bonding. The Charpy impact of OPS plywood developed in this study denoted as PTA was investigated. These properties were compared with the properties of another two types of commercial OPS plywood denoted as PTB and PTC which were manufactured using OPS veneer with tropical hardwood veneer for face and back veneer and control plywood denoted as PTD which was manufactured using 100% tropical hardwood veneer. The results showed that PTA has the highest mean value of energy and strength for both notched and unnotched Charpy impact.
46
KAUFMAN, S. S., D. J. SCRIVNER, N. D. MURRAY, J. A. VANDERHOOF, M. H. HART et D. L. ANTONSON. « Influence of Portagen and Pregestimil on Essential Fatty Acid Status in Infantile Liver Disease ». Pediatrics 89, no 1 (1 janvier 1992) : 151–54. http://dx.doi.org/10.1542/peds.89.1.151.
Texte intégralRésumé :
Nutritional support of the pediatric patient with chronic liver disease continues to pose a challenge to physicians. These patients frequently are profoundly anorexic, have reduced assimilation of dietary fats from intestinal bile acid deficiency and have increased caloric requirements because of hypermetabolism.1 Provision of formula by nasogastric tube may effectively circumvent anorexia while providing additional calories.2 Traditionally, supplying a substantial portion of lipid intake as medium-chain triglyceride (MCT) has also been advocated.3 Rationale for use of MCT in place of usual dietary lipid, ie, long-chain triglyceride (LCT), has included the former's partial hydrolysis and absorption within the stomach, more rapid hydrolysis by pancreatic lipase in the intestinal lumen, and reduced requirement for bile salts to effect aqueous dispersion of free medium-chain fatty acids prior to absorption by intestinal epithelium.4
47
Chen, L. H., et M. J. Bissell. « A novel regulatory mechanism for whey acidic protein gene expression. » Cell Regulation 1, no 1 (novembre 1989) : 45–54. http://dx.doi.org/10.1091/mbc.1.1.45.
Texte intégralRésumé :
When primary mouse mammary epithelial cells (PMME) are cultured on a basement membrane type matrix, they undergo extensive morphogenesis leading to the formation of 3-dimensional alveoli-like spherical structures surrounding a closed lumen. We show for the first time that cells cultured on basement membrane-type matrix express high levels of whey acidic protein (WAP) mRNA and secrete the protein into the lumen. The expression of WAP appears to be dependent upon the formation of the alveoli-like spheres: prevention of sphere formation by fixation or drying of the matrix abolishes the expression of WAP. Co-culturing PMME on native and fixed basement membrane matrix indicates that the suppression of WAP expression is dominant, thereby revealing the existence of a diffusible inhibitor(s). The inhibitory activity is present in the conditioned medium of PMME cultured on plastic surface and floating collagen gels, substrata that do not form alveoli and do not allow WAP expression. These findings are consistent with the model that the synthesis, or the action, of the WAP inhibitory factor is regulated by the tissue-like multicellular organization of mammary cells. When PMME do not have correct 3-dimensional structures, one (or more) inhibitor is secreted into the medium which suppresses WAP expression by an autocrine or paracrine mechanism. Nuclear run-on experiments suggest that the suppression of WAP expression is posttranscriptional. These results have obvious bearings on the understanding of the mechanisms by which cell-cell and cell-extracellular matrix interaction regulate tissue specific gene expressions.
48
Wallner, S., M. Kocifaj, L. Komar et H. A. Solano-Lamphar. « Night-sky imaging as a potential tool for characterization of total lumen output from small and medium-sized cities ». Monthly Notices of the Royal Astronomical Society 494, no 4 (6 mai 2020) : 5008–17. http://dx.doi.org/10.1093/mnras/staa925.
Texte intégralRésumé :
ABSTRACT In this article, the asymptotic formula developed in past work and applied to predict skyglow due to distant sources was evolved, with the objective of characterizing small and medium-sized cities in the observer's surroundings. To enable this, a combination of theoretical computations and in situ measurements is needed, aiming to distinguish between dominant and smaller light-emitting sources, with the latter usually being camouflaged when measuring the night sky. Furthermore, for numerical modelling of skyglow, few of the most important parameters, specifically the amount of total lumens installed and radiated to the upward hemisphere, can be derived. Astronomical observatories, in particular, can profit from this concept, since they are usually situated far away from large cities but can still be surrounded by smaller villages and towns. We present a detailed description of how theoretical computations are combined with all-sky photometry in order to obtain the properties mentioned. Results are compared with satellite data, showing that, regarding approximations undertaken for processing, they are comparable, underlining the functionality of our approach. The idea of including in situ observations enables us to quantify the impact of small and medium-sized cities globally and independent of location, as long as measurements were conducted outside light domes. In addition, the presented work may be of major interest to the light-pollution community if conducting long-term observations of cities, since the quality of commonly used satellite data is going to decrease in the future, due to blindness in short wavelengths and upcoming conversions of public lighting systems to blue-enlightened LEDs.
49
Bakker-Grunwald, Tilly, et Heike Parduhn. « The Ca2+-ATPase activity of Entamoeba histolytica is exposed towards the medium and towards the lumen of intracellular vesicles ». Molecular and Biochemical Parasitology 57, no 1 (janvier 1993) : 167–70. http://dx.doi.org/10.1016/0166-6851(93)90254-u.
Texte intégral
50
Reichel, Valeska, Rosalinde Masereeuw, Jeroen J. M. W. van den Heuvel, David S. Miller et Gert Fricker. « Transport of a fluorescent cAMP analog in teleost proximal tubules ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 293, no 6 (décembre 2007) : R2382—R2389. http://dx.doi.org/10.1152/ajpregu.00029.2007.
Texte intégralRésumé :
Previous studies have shown that killifish ( Fundulus heteroclitus) renal proximal tubules express a luminal membrane transporter that is functionally and immunologically analogous to the mammalian multidrug resistance-associated protein isoform 2 (Mrp2, ABCC2). Here we used confocal microscopy to investigate in killifish tubules the transport of a fluorescent cAMP analog (fluo-cAMP), a putative substrate for Mrp2 and Mrp4 (ABCC4). Steady-state luminal accumulation of fluo-cAMP was concentrative, specific, and metabolism-dependent, but not reduced by high K+ medium or ouabain. Transport was not affected by p-aminohippurate (organic anion transporter inhibitor) or p-glycoprotein inhibitor (PSC833), but cell-to-lumen transport was reduced in a concentration-dependent manner by Mrp inhibitor MK571, leukotriene C4 (LTC4), azidothymidine (AZT), cAMP, and adefovir; the latter two compounds are Mrp4 substrates. Although MK571 and LTC4 reduced transport of the Mrp2 substrate fluorescein-methotrexate (FL-MTX), neither cAMP, adefovir, nor AZT affected FL-MTX transport. Fluo-cAMP transport was not reduced when tubules were exposed to endothelin-1, Na nitroprusside (an nitric oxide generator) or phorbol ester (PKC activator), all of which signal substantial reductions in cell-to-lumen FL-MTX transport. Fluo-cAMP transport was reduced by forskolin, and this reduction was blocked by the PKA inhibitor H-89. Finally, in membrane vesicles from Spodoptera frugiperda (Sf9) cells containing human MRP4, ATP-dependent and specific uptake of fluo-cAMP could be demonstrated. Thus, based on inhibitor specificity and regulatory signaling, cell-to-lumen transport of fluo-cAMP in killifish renal tubules is mediated by a transporter distinct from Mrp2, presumably a teleost form of Mrp4.