scholarly journals Inactivation of endothelin by polymorphonuclear leukocyte-derived lytic enzymes

Blood ◽  
1991 ◽  
Vol 78 (10) ◽  
pp. 2715-2720
Author(s):  
P Patrignani ◽  
A Del Maschio ◽  
G Bazzoni ◽  
L Daffonchio ◽  
A Hernandez ◽  
...  
Keyword(s):  
High Performance ◽  
Rabbit Aorta ◽  
Maximal Activity ◽  
Time Frame ◽  
Cell Number ◽  
Cathepsin G ◽  
Lytic Enzymes ◽  
Intact Cells ◽  
Aortic Endothelial Cells ◽  
Eglin C

Cultured bovine aortic endothelial cells (BAEC) released endothelin-1 (ET-1) in the culture medium in a time-dependent fashion. Coincubation of fMLP-activated human polymorphonuclear leukocytes (PMN) with BAEC caused a fast (maximal activity was reached within 15 minutes) and cell number-dependent disappearance of ET-1 from the medium. This effect was direct to ET-1, because it was also present when PMN were incubated with the synthetic peptide in the absence of BAEC. PMN-dependent disappearance of ET-1 was associated with loss of constrictor activity on isolated rabbit aorta. PMN-released products were responsible for ET- 1 degrading activity, because supernatants of activated PMN were equally effective as the intact cells. Resting PMN, in the same time frame, were uneffective. Eglin C, a potent blocker of PMN-derived elastase and cathepsin G, reversed the ET-1 inhibitory activity of fMLP- stimulated PMN and of their supernatant. Direct addition of elastase and cathepsin G to synthetic ET-1 destroyed its immunoreactivity and this effect was blocked by eglin C. High-performance liquid chromatography (HPLC) analysis supported the hypothesis that ET-1 degradation by PMN was due to enzymatic proteolysis. These data provide evidence that activated PMN are able to degrade ET-1 through the release of proteases. Because physiologic concentrations of PMN can destroy high amounts (up to 100 nmol/L) of ET-1 within a few minutes, we propose that this mechanism of ET-1 inactivation has biologic relevance.

scholarly journals Inactivation of endothelin by polymorphonuclear leukocyte-derived lytic enzymes

Blood ◽  
1991 ◽  
Vol 78 (10) ◽  
pp. 2715-2720 ◽  
Author(s):  
P Patrignani ◽  
A Del Maschio ◽  
G Bazzoni ◽  
L Daffonchio ◽  
A Hernandez ◽  
...  
Keyword(s):  
High Performance ◽  
Rabbit Aorta ◽  
Maximal Activity ◽  
Time Frame ◽  
Cell Number ◽  
Cathepsin G ◽  
Lytic Enzymes ◽  
Intact Cells ◽  
Aortic Endothelial Cells ◽  
Eglin C

Abstract Cultured bovine aortic endothelial cells (BAEC) released endothelin-1 (ET-1) in the culture medium in a time-dependent fashion. Coincubation of fMLP-activated human polymorphonuclear leukocytes (PMN) with BAEC caused a fast (maximal activity was reached within 15 minutes) and cell number-dependent disappearance of ET-1 from the medium. This effect was direct to ET-1, because it was also present when PMN were incubated with the synthetic peptide in the absence of BAEC. PMN-dependent disappearance of ET-1 was associated with loss of constrictor activity on isolated rabbit aorta. PMN-released products were responsible for ET- 1 degrading activity, because supernatants of activated PMN were equally effective as the intact cells. Resting PMN, in the same time frame, were uneffective. Eglin C, a potent blocker of PMN-derived elastase and cathepsin G, reversed the ET-1 inhibitory activity of fMLP- stimulated PMN and of their supernatant. Direct addition of elastase and cathepsin G to synthetic ET-1 destroyed its immunoreactivity and this effect was blocked by eglin C. High-performance liquid chromatography (HPLC) analysis supported the hypothesis that ET-1 degradation by PMN was due to enzymatic proteolysis. These data provide evidence that activated PMN are able to degrade ET-1 through the release of proteases. Because physiologic concentrations of PMN can destroy high amounts (up to 100 nmol/L) of ET-1 within a few minutes, we propose that this mechanism of ET-1 inactivation has biologic relevance.

Endopeptidases 3.4.24.15 and 24.16 in endothelial cells: potential role in vasoactive peptide metabolism

2003 ◽  
Vol 284 (6) ◽  
pp. H1978-H1984 ◽  
Author(s):  
M. Ursula Norman ◽  
Shane B. Reeve ◽  
Vincent Dive ◽  
A. Ian Smith ◽  
Rebecca A. Lew
Keyword(s):  
Endothelial Cells ◽  
High Performance ◽  
Vascular Endothelial Cells ◽  
Umbilical Vein ◽  
Hybrid Cell ◽  
Fluorescent Substrate ◽  
Intact Cells ◽  
Aortic Endothelial Cells

The closely related metalloendopeptidases EC 3.4.24.15 (EP24.15; thimet oligopeptidase) and 24.16 (EP24.16; neurolysin) cleave a number of vasoactive peptides such as bradykinin and neurotensin in vitro. We have previously shown that hypotensive responses to bradykinin are potentiated by an inhibitor of EP24.15 and EP24.16 (26), suggesting a role for one or both enzymes in bradykinin metabolism in vivo. In this study, we have used selective inhibitors that can distinguish between EP24.15 and EP24.16 to determine their activity in cultured endothelial cells (the transformed human umbilical vein endothelial hybrid cell line EA.hy926 or ovine aortic endothelial cells). Endopeptidase activity was assessed using a specific quenched fluorescent substrate [7-methoxycoumarin-4-acetyl-Pro-Leu-Gly-d-Lys(2,4-dinitrophenyl)], as well as the peptide substrates bradykinin and neurotensin (assessed by high-performance liquid chromatography with mass spectroscopic detection). Our results indicate that both peptidases are present in endothelial cells; however, EP24.16 contributes significantly more to substrate cleavage by both cytosolic and membrane preparations, as well as intact cells, than EP24.15. These findings, when coupled with previous observations in vivo, suggest that EP24.16 activity in vascular endothelial cells may play an important role in the degradation of bradykinin and/or other peptides in the circulation.

The Recent Revolution in High Performance Computing

MRS Bulletin ◽  
1997 ◽  
Vol 22 (10) ◽  
pp. 5-6
Author(s):  
Horst D. Simon
Keyword(s):  
High Performance Computing ◽  
High Performance ◽  
New Technologies ◽  
New Technology ◽  
Parallel Architecture ◽  
Time Frame ◽  
Good News ◽  
Computing Industry ◽  
Time And Energy ◽  
Performance Computing

Recent events in the high-performance computing industry have concerned scientists and the general public regarding a crisis or a lack of leadership in the field. That concern is understandable considering the industry's history from 1993 to 1996. Cray Research, the historic leader in supercomputing technology, was unable to survive financially as an independent company and was acquired by Silicon Graphics. Two ambitious new companies that introduced new technologies in the late 1980s and early 1990s—Thinking Machines and Kendall Square Research—were commercial failures and went out of business. And Intel, which introduced its Paragon supercomputer in 1994, discontinued production only two years later.During the same time frame, scientists who had finished the laborious task of writing scientific codes to run on vector parallel supercomputers learned that those codes would have to be rewritten if they were to run on the next-generation, highly parallel architecture. Scientists who are not yet involved in high-performance computing are understandably hesitant about committing their time and energy to such an apparently unstable enterprise.However, beneath the commercial chaos of the last several years, a technological revolution has been occurring. The good news is that the revolution is over, leading to five to ten years of predictable stability, steady improvements in system performance, and increased productivity for scientific applications. It is time for scientists who were sitting on the fence to jump in and reap the benefits of the new technology.

scholarly journals A thin, deformable, high-performance supercapacitor implant that can be biodegraded and bioabsorbed within an animal body

2021 ◽  
Vol 7 (2) ◽  
pp. eabe3097
Author(s):  
Hongwei Sheng ◽  
Jingjing Zhou ◽  
Bo Li ◽  
Yuhang He ◽  
Xuetao Zhang ◽  
...  
Keyword(s):  
High Performance ◽  
Electronic Devices ◽  
Form Factors ◽  
Time Frame ◽  
Water Soluble ◽  
Two Dimensional ◽  
Medical Electronics ◽  
Thin Structure ◽  
Shed Light

It has been an outstanding challenge to achieve implantable energy modules that are mechanically soft (compatible with soft organs and tissues), have compact form factors, and are biodegradable (present for a desired time frame to power biodegradable, implantable medical electronics). Here, we present a fully biodegradable and bioabsorbable high-performance supercapacitor implant, which is lightweight and has a thin structure, mechanical flexibility, tunable degradation duration, and biocompatibility. The supercapacitor with a high areal capacitance (112.5 mF cm−2 at 1 mA cm−2) and energy density (15.64 μWh cm−2) uses two-dimensional, amorphous molybdenum oxide (MoOx) flakes as electrodes, which are grown in situ on water-soluble Mo foil using a green electrochemical strategy. Biodegradation behaviors and biocompatibility of the associated materials and the supercapacitor implant are systematically studied. Demonstrations of a supercapacitor implant that powers several electronic devices and that is completely degraded after implantation and absorbed in rat body shed light on its potential uses.

scholarly journals Measurement and clinical usefulness of bilirubin in liver disease

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Armando Raúl Guerra Ruiz ◽  
Javier Crespo ◽  
Rosa Maria López Martínez ◽  
Paula Iruzubieta ◽  
Gregori Casals Mercadal ◽  
...  
Keyword(s):  
Bile Ducts ◽  
High Performance ◽  
Liver Lesion ◽  
Cell Number ◽  
Direct Bilirubin ◽  
Liver Uptake ◽  
Biochemical Alterations ◽  
Indirect Bilirubin ◽  
Impaired Liver ◽  
Direct Spectrophotometry

Abstract Elevated plasma bilirubin levels are a frequent clinical finding. It can be secondary to alterations in any stage of its metabolism: (a) excess bilirubin production (i.e., pathologic hemolysis); (b) impaired liver uptake, with elevation of indirect bilirubin; (c) impaired conjugation, prompted by a defect in the UDP-glucuronosyltransferase; and (d) bile clearance defect, with elevation of direct bilirubin secondary to defects in clearance proteins, or inability of the bile to reach the small bowel through bile ducts. A liver lesion of any cause reduces hepatocyte cell number and may impair the uptake of indirect bilirubin from plasma and diminish direct bilirubin transport and clearance through the bile ducts. Various analytical methods are currently available for measuring bilirubin and its metabolites in serum, urine and feces. Serum bilirubin is determined by (1) diazo transfer reaction, currently, the gold-standard; (2) high-performance liquid chromatography (HPLC); (3) oxidative, enzymatic, and chemical methods; (4) direct spectrophotometry; and (5) transcutaneous methods. Although bilirubin is a well-established marker of liver function, it does not always identify a lesion in this organ. Therefore, for accurate diagnosis, alterations in bilirubin concentrations should be assessed in relation to patient anamnesis, the degree of the alteration, and the pattern of concurrent biochemical alterations.

scholarly journals Interacting cell populations in cultures of leukocytes from normal or leukemic peripheral blood

Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 269-280
Keyword(s):  
Thymidine Incorporation ◽  
Kinetic Studies ◽  
Cell Interaction ◽  
Cell Number ◽  
Cellular Interaction ◽  
Intact Cells ◽  
Quantitative Evidence ◽  
Peripheral Leukocytes ◽  
Limiting Dilution ◽  
Stimulation Of

Kinetic studies in cultures containing 2 X 10(5) peripheral leukocytes from patients with acute myelobastic leukemia revealed extensive, radiation-sensitive increases in thymidine incorporation without parallel increases in cell number. Modest and variable stimulation of 3HTdR incorporation was seen with the addition of either leukocyte- conditioned medium prepared with phytohemagglutin (PHA) or PHA alone. However, using the method of limiting dilution, stimulation was always observed and ranged from 3- to 20-fold in individual patients. By mixing small numbers of intact cells with larger numbers of irradiated autologous cells, quantitative evidence was obtained for a cellular interaction between irradiated, PHA-stimulated populations capable of 3HTdR incorporation. Similar evidence for cell-cell interaction was obtained for normal leukocytes.

Effects of thrombospondin antibody on the recovery of endothelial cells from hyperthermia

1990 ◽  
Vol 96 (2) ◽  
pp. 263-270
Author(s):  
N.V. Ketis ◽  
J. Lawler
Keyword(s):  
Endothelial Cells ◽  
Heat Shock ◽  
Time Frame ◽  
Heparin Binding ◽  
Cytoskeletal Organization ◽  
Aortic Endothelial Cells ◽  
Bovine Aortic Endothelial Cells ◽  
Heparin Binding Domain ◽  
Cell Processes ◽  
Shock Proteins

In addition to the increased synthesis of the classical heat-shock proteins (28,000, 71,000, 73,000, 90,000 and 100,000 Mr polypeptides) there is also an increase of thrombospondin in the growth medium of endothelial cells exposed to hyperthermia. The effect of a monoclonal antibody to thrombospondin on the recovery of endothelial cells from hyperthermia as it relates to cytoskeletal organization and cell spreading was assessed. The antibody interacts with the heparin-binding domain of thrombospondin in the extracellular matrix of cells. We report that during recovery from thermal insult at 37 degrees C, intermediate filaments, stress fibres and microtubules show distinct time-recovery characteristics in bovine aortic endothelial cells; that in the presence of this antibody the cytoskeleton is notably altered; that this antibody causes retraction of endothelial cell processes; and that the recovery of the cytoskeleton in endothelial cells exposed to hyperthermia is prevented by the thrombospondin antibody in the time frame examined. Our data suggest that the recovery of cells from heat shock requires the integrity of thrombospondin and its interactions.

Adenoviral expression of 15-lipoxygenase-1 in rabbit aortic endothelium: role in arachidonic acid-induced relaxation

2007 ◽  
Vol 292 (2) ◽  
pp. H1033-H1041 ◽  
Author(s):  
Nitin T. Aggarwal ◽  
Blythe B. Holmes ◽  
Lijie Cui ◽  
Helena Viita ◽  
Seppo Yla-Herttuala ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Rabbit Aorta ◽  
Epoxyeicosatrienoic Acid ◽  
Aortic Endothelial Cells ◽  
Aortic Endothelium ◽  
Rate Limiting Step ◽  
Immunohistochemical Studies ◽  
Rate Limiting

Endothelium-dependent vasorelaxation of the rabbit aorta is mediated by either nitric oxide (NO) or arachidonic acid (AA) metabolites from cyclooxygenase (COX) and 15-lipoxygenase (15-LO) pathways. 15-LO-1 metabolites of AA, 11,12,15-trihydroxyeicosatrienoic acid (THETA), and 15-hydroxy-11,12-epoxyeicosatrienoic acid (HEETA) cause concentration-dependent relaxation. We tested the hypothesis that in the 15-LO pathway of AA metabolism, 15-LO-1 is sufficient and is the rate-limiting step in inducing relaxations in rabbit aorta. Aorta and rabbit aortic endothelial cells were treated with adenoviruses containing human 15-LO-1 cDNA (Ad-15-LO-1) or β-galactosidase (Ad-β-Gal). Ad-15-LO-1-transduction increased the expression of a 75-kDa protein corresponding to 15-LO-1, detected by immunoblotting with an anti-human15-LO-1 antibody, and increased the production of HEETA and THETA from [14C]AA. Immunohistochemical studies on Ad-15-LO-1-transduced rabbit aorta showed the presence of 15-LO-1 in endothelial cells. Ad-15-LO-1-treated aortic rings showed enhanced relaxation to AA (max 31.7 ± 3.2%) compared with Ad-β-Gal-treated (max 12.7 ± 3.2%) or control nontreated rings (max 13.1 ± 1.6%) ( P < 0.01). The relaxations in Ad-15-LO-1-treated aorta were blocked by the 15-LO inhibitor cinnamyl-3,4-dihydroxy-a-cyanocinnamate. Overexpression of 15-LO-1 in the rabbit aortic endothelium is sufficient to increase the production of the vasodilatory HEETA and THETA and enhance the relaxations to AA. This confirms the role of HEETA and THETA as endothelium-derived relaxing factors.

Endothelium-derived relaxant factor inhibits effects of nitrocompounds in isolated arteries

1987 ◽  
Vol 252 (2) ◽  
pp. H307-H313
Author(s):  
U. Pohl ◽  
R. Busse
Keyword(s):  
Endothelial Cells ◽  
Femoral Artery ◽  
Response Curve ◽  
Rabbit Aorta ◽  
Nordihydroguaiaretic Acid ◽  
Aortic Endothelial Cells ◽  
Bovine Aortic Endothelial Cells ◽  
Basal Release ◽  
Isolated Arteries

We investigated the influence of endothelial cells on the smooth muscle vasodilator effects to sodium nitroprusside (SNP) or Teopranitol (an organic mononitrate) in isolated segments of rabbit aorta and femoral artery. In the femoral artery, the vasodilator responses to both nitrocompounds were significantly higher in the absence of endothelial cells or after pretreatment with the endothelium-derived relaxant factor (EDRF) inhibitor nordihydroguaiaretic acid (NDGA; 10 microM). Moreover, under conditions of stimulated EDRF release (induced by acetylcholine; 30–100 nM) the vasodilator responses to SNP were further attenuated in vessels with intact endothelium. By contrast, in the rabbit aorta, the vasodilator responses to the nitrocompounds were not significantly altered by either endothelium removal or treatment with NDGA. However, in the presence of the EDRF stimulator acetylcholine, the dose-response curve to SNP was shifted to right in the aorta as well. The role of EDRF in the endothelium-mediated attenuation of the dilator potency of SNP was further investigated by using EDRF released from cultured (bovine aortic) endothelial cells. The dilator effects of SNP were compared in endothelium denuded femoral or aortic segments in the presence or absence of EDRF. The vasodilator effects of SNP in both types of arteries were significantly reduced in the presence of EDRF. We conclude that EDRF attenuates the arterial vasodilation induced by SNP and Teopranitol. The results further suggest that endothelial cells exhibit a greater basal release of EDRF in the femoral artery than in the aorta, since under unstimulated conditions an EDRF-induced attenuation was seen only in femoral and not in aortic segments.

Vascular Angiotensin-Converting Enzyme Activity in Man and other Species

1984 ◽  
Vol 66 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Mizuo Miyazaki ◽  
Hideki Okunishi ◽  
Kazuo Nishimura ◽  
Noboru Toda
Keyword(s):  
Angiotensin Converting Enzyme ◽  
High Performance ◽  
Muscle Tone ◽  
Chloride Ion ◽  
Kidney Cortex ◽  
Dependent Manner ◽  
Converting Enzyme ◽  
Aortic Endothelial Cells ◽  
Ace Activity ◽  
Dose Dependent

1. Angiotensin-converting enzyme (ACE) activity in blood vessels of different species was determined. 2. ACE was solubilized by Nonidet P-40, and assayed by reversible phase high performance liquid chromatography. Approximately 98% ACE was recovered in the liquid phase by the use of the detergent. 3. The ACE activity varied with chloride ion (Cl−) concentrations; the maximum activities in dog, human, monkey and rabbit tissues were obtained at the concentrations of 800, 600, 600 and 300 mmol/l respectively. The optimal Cl− concentration was quite similar in different tissues and plasma obtained from the same species. 4. The ACE activity in the cerebral, mesenteric, pulmonary and renal arteries was in a range between 1.01 and 1.60 m-units/mg of protein in dogs and between 0.43 and 0.94 m-unit/mg of protein in monkeys. The activity in dog aortae was 0.20 ± 0.02 m-unit/mg of protein, and the activity in aortic endothelial cells was 2.61 ± 0.65 m-units/mg of protein. ACE activities in the dog lung, kidney cortex and cerebral cortex were 28.6 ± 2.6, 15.7 ± 3.0 and 3.5 ± 0.6m-units/mg of protein respectively. SA-446, a captopril-like ACE inhibitor, reduced the ACE activity in arteries in a dose-dependent manner. 5. Vascular ACE appears to be concentrated in the endothelium and may contribute to regulate vascular muscle tone and local blood flow by a conversion of angiotensin I into II.

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