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11.
Thomas J. Jentsch Svea K. Keller Marianne Koch Michael Wiederholt 《The Journal of membrane biology》1984,81(3):189-204
Summary Usin gintracellular microelectrode technique, the response of the voltageV across the plasma membrane of cultured bovine corneal endothelial cells to changes in sodium and bicarbonate concentrations was investigated. (1) The electrical response to changes in [HCO
3
–
]
o
(depolarization upon lowering and hyperpolarization upon raising [HCO
3
–
]
o
) was dependent on sodium. Lithium could fairly well be substituted for sodium, whereas potassium or choline were much less effective. (2) Removal of external sodium caused a depolarization, while a readdition led to a hyperpolarization, which increased with time of preincubation in the sodium-depleted medium. (3) The response to changes in [Na+]
o
was dependent on bicarbonate. In a nominally bicarbonate-free medium, its amplitude was decreased or even reversed in sign. (4) Application of SITS or DIDS (10–3
m) had a similar effect on the response to sodium as bicarbonate-depleted medium. (5) At [Na+]
o
=151mm and [HCO
3
–
]
o
=46mm, the transients ofV depended, with 39.0±9.0 (sd) mV/decade, on bicarbonate and, with 15.3±5.8 (sd) mV/decade, on sodium. (6) After the preincubation of cells with lithium, replacement of Li by choline led to similar effects as the replacement of sodium by choline, though the response ofV was smaller with Li. This response could be reduced or reversed by the removal of bicarbonate or by the application of SITS. (7) Amiloride (10–3
m) caused a reversible hyperpolarization of the steady-state potential by 8.5±2.6 mV (sd). It did not affect the immediate response to changes in [Na+]
o
or [HCO
3
–
]
o
, but reduced the speed of regaining the steady-state potential after a change in [HCO
3
–
]
o
. (8) Ouabain (10–4
m) caused a fast depolarization of –6.8±1.1 (sd) mV, which was followed by a continuing slower depolarization. The effect was almost identical at 10–5
m. (9) It is suggested, that corneal endothelial cells possess a cotransport for sodium and bicarbonate, which transports net negative charage with these ions. It is inhibitable by stilbenes, but not directly affected by amiloride or ouabain. Lithium is a good substitute for sodium with respect to bicarbonate transport and is transported itself. In addition, the effect of amiloride provides indirect evidence for the existence of a Na+/H+-antiport. A model for the transepithelial transport of bicarbonate across the corneal endothelium is proposed. 相似文献
12.
Dennis Way Mary Hendrix Marlys Witte Charles Witte Ray Nagle John Davis 《In vitro cellular & developmental biology. Plant》1987,23(9):647-652
Summary An endothelial cell line derived from a massive recurrent chyle-containing retroperitoneal lymphangioma was isolated in monolayer
culture. Scanning and transmission electron microscopy and immunohistochemistry confirmed a close resemblance to blood vascular
endothelium with typical cobblestone morphology, positive immunofluorescence staining for endothelial marker Factor VIII-associated
antigen and fibronectin, and prominent Weibel-Palade bodies. The endothelial cells also exhibited other ultrastructural features
characteristic of lymphatic endothelium, including sparse microvillous surface projections, overlapping intercellular junctions,
and abundant intermediate filaments. This endothelial cell line represents a new source of proliferating lymphatic endothelium
for future study, including structural and functional comparison to blood vascular endothelium.
Supported in part by Arizona Disease Control Research Commission contracts 8277-000000-1-1-AT-6625 and ZB-7492. Presented
in part at the 10th International Congress of Lymphology in Adelaide, Australia, August 1985. 相似文献
13.
David Dichek Thomas Quertermous 《In vitro cellular & developmental biology. Plant》1989,25(3):289-292
Summary Levels of seven messenger RNA species were compared in human umbilical vein endothelial cells of different lineage and time
in culture. Specifically, cells obtained from the American Type Culture Collection (ATCC) and subcultured were compared to
early passage cells from cultures produced in our laboratory. Messenger RNA for tissue plasminogen activator, plaminogen activator
inhibitor 1, urokinase, and thrombomodulin were expressed at higher levels in the ATCC cells. Thrombospondin, von Willebrand's
Factor, and protein S messenger RNA were expressed at higher levels in the cells that we isolated. In addition, in the ATCC
cells a shift in the proportion of plasminogen activator inhibitor messenger RNA from the 3.4 to the 2.4 kilobase species
was found. We conclude that specific messenger RNA levels can vary considerably between cultured human umbilical vein endothelial
cells. The large variation in mRNA levels which we describe has important implications for experiments involving gene expression
in cultured endothelium. 相似文献
14.
Role of the Blood-Brain Barrier in the Formation of Long-Chain ω-3 and ω-6 Fatty Acids from Essential Fatty Acid Precursors 总被引:3,自引:3,他引:0
Elongated, more highly polyunsaturated derivatives of linoleic acid (18:2 omega-6) and linolenic acid (18:3 omega-3) accumulate in brain, but their sites of synthesis and mechanism of entry are not well characterized. To investigate the role of the blood-brain barrier in this process, cultured murine cerebromicrovascular endothelia were incubated with [1-14C]18:2 omega-6 or [1-14C]18:3 omega-3 and their elongation/desaturation products determined. The major metabolite of 18:2 omega-6 was 20:4 omega-6, whereas the primary product from 18:3 omega-3 was 20:5 omega-3. Although these products were found primarily in cell lipids, they were also released from the cells and gradually accumulated in the extracellular fluid. Eicosanoid production was observed from the 20:4 omega-6 and 20:5 omega-3 that were formed. No 22:5 omega-6 or 22:6 omega-3 fatty acids were detected, suggesting that these endothelial cells are not the site of the final desaturation step. Although the uptake of 18:3 omega-3 and 18:2 omega-6 was nearly identical, 18:3 omega-3 was more extensively elongated and desaturated. Competition experiments demonstrated a preference for 18:3 omega-3 by the elongation/desaturation pathway. These findings suggest that the blood-brain barrier can play an important role in the elongation and desaturation of omega-3 and omega-6 essential fatty acids during their transfer from the circulation into the brain. 相似文献
15.
Roberto F. Nicosia Antonio Ottinetti 《In vitro cellular & developmental biology. Plant》1990,26(2):119-128
Summary Rings of rat aorta cultured in Matrigel, a reconstituted gel composed of basement membrane molecules, gave rise to three-dimensional
networks composed of solid cellular cords and occasional microvessels with slitlike lumina. Immunohistochemical and ultrastructural
studies showed that the solid cords were composed of endothelial sprouts surrounded by nonendothelial mesenchymal cells. The
angiogenic response of the aortic rings in Matrigel was compared to that obtained in interstitial collagen, fibrin, or plasma
clot. Morphometric analysis demonstrated that the mean luminal area of the microvascular sprouts and channels was significantly
smaller in Matrigel than in collagen, fibrin, or plasma clot. The percentage of patent microvessels in Matrigel was also markedly
reduced. Autoradiographic studies of3H-thymidine-labeled cultures showed reduced DNA synthesis by developing microvessels in Matrigel. The overall number of solid
endothelial cords and microvessels was lower in Matrigel than in fibrin or plasma clot. A mixed cell population isolated from
Matrigel cultures formed a monolayer in collagen or fibrin-coated dishes but rapidly reorganized into a polygonal network
when plated on Matrigel. The observation that gels composed of basement membrane molecules modulate the canalization, proliferation,
and organization into networks of vasoformative endothelial cells in three-dimensional cultures supports the hypothesis that
the basement membrane is a potent regulator of microvascular growth and morphogenesis.
This work was supported by grants from the W. W. Smith Charitable Trust and grants CA14137 and HL43392 from the National Institutes
of Health, Bethesda, MD. 相似文献
16.
Paracrine functions of the coronary vascular endothelium 总被引:5,自引:0,他引:5
Ingrid Fleming Johann Bauersachs Rudi Busse 《Molecular and cellular biochemistry》1996,157(1-2):137-145
17.
Obst O. O. Linssen M. C. J. G. Vusse G. J. v. d. Kammermeier H. 《Molecular and cellular biochemistry》1996,163(1):173-180
Marked concentration differences of noradrenaline (NA) between the vascular and the interstitial compartment were detected by sampling interstitial transudate from isolated perfused rat hearts. The ratios of vascular/interstitial concentration amounted to 7.4 to 1.3 depending on the concentration of NA administered (3 × 10–9 to 10–6 M). These concentration differences were abolished by inhibitors of uptake1 desipramine (DMI) I and uptake, (O-methyl-isoprenaline (OMI)). Neuronal uptake, was characterized by a Km of 0.22 mol/l and a Vmax of 370 pmol × min–1 × gWWT–1, extraneuronal uptake2 by a KUPTAKE of = 0.313 min–4.The apparent permeability surface area (P×S)-product calculated from uptake rate and transcapillary concentration difference was significantly decreased by administrating 100 mol/l (NA) in presence of DMI. A presumed endothelial uptake mechanism contributing to catecholamine translocation was investigated in endothelial cells in culture. These cells showed a specific noradrenaline uptake with a Km of 4.35 mol/l and a Vmax of about 75 pmol × min–1 x gWWT–1. Any inhibiton by inhibitors of both of the two noradrenaline uptakes was lacking. The uptake rate of this mechanism is insufficient to contribute to the diffusive conductivity of the capillary wall (P × S-product). We conclude from our investigations on interstitial concentrations of catecholamines and transcapillary concentration differences, that the capillary wall, owing to its metabolic and diffusional characteristics, influences the exchange of catecholamines to a substantial and physiologically relevant extent. 相似文献
18.
Cultures of endothelial cells and cell lines of endothelial origin were maintained at confluence without medium exchange for a period of 72 h. During this time period the concentration of nutrients — amino acids and glucose — and metabolic waste products — lactate and ammonium — was determined as well as cell vitality and cell numbers. Metabolic rates were calculated and compared for the different cell lines. Surprisingly the primary cells showed significantly higher rates of glucose and glutamine consumption, respectively lactate production than the immortalized cell lines. Except for one tumorigenic cell line all cells showed a significant participation of transaminases in glutamine/ammonium metabolism. Furthermore it could be shown that in routine culture there was no depletion of nutrients or critical accumulation of ammonium or lactate over a culture period of 72 h.Abbreviations BAEC
bovine aorta endothelial cells
- EC
vascular endothelial cells
- FGF
fibroblast growth factor
- HUVEC
vascular endothelial cells from human umbilical cord veins
- IF
1:1 mixture of Iscove's MDM and Ham's F12 basal media
- MTT
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid
- NCS
newborn calf serum
- PBS
phosphate buffered saline
- TE
0.05% (w/V) trypsin, 0.02% (w/v) EDTA in PBS 相似文献
19.
内毒素血症大鼠肠系膜微循环中血管内皮细胞与白细胞的粘附性变化 总被引:1,自引:0,他引:1
常青 《中国应用生理学杂志》1994,10(4):344-347
本实验采用中文吖啶橙荧光标记技术,结合微循环观察用显微超高速摄录像装置,观察了内毒素对微血管内白细胞与微静脉血管内皮细胞的粘附性的影响。结果表明,内毒素对大鼠的血压、微血管口径和微动脉血流速度影响不大,微静脉血流速度在滴注内毒素后45和60min下降了16.67%和17.95%(P<0.05);但内毒素能迅速改变微静脉内的白细胞流态,明显增加附壁滚动的白细胞数和粘附白细胞密度指数,经测量同一微静脉内的白细胞和红细胞流速,求得白细胞与微静脉内皮细胞之间的破裂力在5min和15min时下降了25.96%和42.88%(P<0.01),下降趋势持续整个实验过程;说明内毒素能明显地增加白细胞与微静脉血管内皮细胞之间的粘附力。由此提示,研究白细胞与微静脉血管内皮细胞之间粘附力增强机制及寻找其抑制因素对改善微循环紊乱、抢救休克具有重要的临床意义。 相似文献
20.
Louis Faso Richard S. Trowbridge Wei Quan Xiu-Lan Yao Edmund C. Jenkins Alma Maciulis Thomas D. Bunch Henry M. Wisniewski 《In vitro cellular & developmental biology. Animal》1994,30(4):226-235
Summary A strain of cerebral endothelial cells was established from isolated cortical microvessels of caprine brain. These cells,
which are referred to as ECl cells, can be routinely subcultured to 32 passages without the loss of differentiated morphologic
and immunologic traits. The ability to routinely subculture ECl cells is an important asset, given that isolated cerebral
endothelial cells in mammals generally lose their differentiated traits after only 2 to 3 passages.
ECl cells were shown to contain Factor VIII-related antigen, which is a specific marker for cells of endothelial origin. ECl
cells morphologically demonstrated a scarcity of pinocytotic vesicles on their apical surfaces, a lack of trans-cytoplasmic
vesicles, and the ability to form in culture confluent monolayers with tight junctional complexes. Therefore, ECl cells possess
specific antigenic and ultrastructural features which classify them as being small vessel endothelial cells of the blood-brain
barrier type. Cytogenetic evaluation of ECl cells demonstrated a normal female goat 60,XX karyotype and confirmed the apparent
non-transformed nature of ECl cells due to the lack of chromosome abnormalities or rearrangements. Using scanning electron
microscopy, ECl cells were also shown to form confluent monolayers on mixed nitrocellulose filters, a feature that will enable
the development of an in vitro system to study trans-endothelial transport. Given that ECl cells are readily subcultured and
grow well on nitrocellulose filters, and that they resemble cerebral endothelium in vivo, it seems evident that ECl cells
can be used as a versatile model for the study of blood-brain barrier function, regulation, and pathology. 相似文献