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排序方式: 共有275条查询结果,搜索用时 359 毫秒
1.
Klausner J. M.; Kobzik L.; Valeri C. R.; Shepro D.; Hechtman H. B. 《Journal of applied physiology》1988,65(1):80-88
This study tests whether activated complement leads to a selective entrapment of polymorphonuclear leukocytes (PMN's) in the lungs. Awake sheep were infused for 5 min with zymosan-activated plasma (ZAP, 2.5 mg/ml) at a rate of 5 ml/min into the superior vena cava (IV, n = 4) or intra-arterially into the aortic arch or femoral artery (IA, n = 8). At the end of IV infusion, leukocyte counts fell from 8,862 to 1,631/mm3 (P less than 0.01). PMN counts across the lungs decreased by 74%. There were increases in plasma thromboxane (Tx) B2 from 114 to 2,733 pg/ml (P less than 0.01), mean pulmonary arterial pressure from 12 to 42 mmHg (P less than 0.01), and physiological shunt from 13 to 25% (P less than 0.05). Within 1 h lymph TxB2 levels had risen from 301 to 4,916 pg/ml (P less than 0.01), lung lymph flow (QL) rose from 3.7 to 11.1 ml/30 min (P less than 0.05), lymph-to-plasma protein ratio (L/P) remained unchanged at 0.63, and lymph protein clearance increased from 2.3 to 7.5 ml/30 min (P less than 0.05). Leukosequestration, quantitated by capillary PMN counting and by assaying the granulocyte marker myeloperoxidase, occurred relative to sham animals (P less than 0.05) in the lung and spleen but not in other organs. Intra-arterial ZAP infusion led to changes that were similar in magnitude and timing to the IV group.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
2.
The authors studied by means of sterological methods the volume density of syncytial sprouts in different cotyledonary regions of the human term placenta. The syncytial sprouts account for 4.92% of the placenta volume. Meanwhile, there were significant differences according to the site from which the sample was obtained. The lowest value (2.72%) corresponds to the central-parabasal zone of the cotyledon, close to the entry of the maternal blood into the intervillous space, whereas the highest values correspond to the "venous" regions. The results of the present study, as well as those reported by others, suggest that the lateral-subchorial zone would be the growing region of the cotyledon. 相似文献
3.
Granulocytes isolated by counterflow centrifugation elutriation (CCE) from leukapheresed dog blood, frozen in liquid nitrogen at ?196 °C, were studied. The effects of long-term cryopreservation on cell recovery and in vitro function were detertmined. In seven separate experiments, an average of 1.7 × 109 granulocytes were obtained. The white cell differential count was 91% granulocytes and 9% mononuclear cells. There was less than 5% red cells presrent and no platelets. Granulocytes were placed in Hemoflex bags and mixed slowly with equal volumes of sterile ice-cold hyperosmolar cryoprotectant buffer to make a final composition of 5% dimethylsulfoxide (DMS), 6% hydroxyethyl starch (HES), and 4% bovine serum albumin (BSA), pH 7.1. Total volumes of 40 ml were frozen at a cooling rate of 4 °C per minute and stored for periods of 1, 34, 60, 90, and 132 weeks in liquid nitrogen at ?196 °C. Thawing was done at a rate of 190 ° per minute to 10 °C. The recovery of cells was 95%, 105%, 100%, 100%, and 88% respectively. Ethidium bromide exclusion, indicative of viable nuclei, was 91%, 81%, 94%, 89%, and 80% respectively. Virtually all thawed cells ingested opsonized Fluolite particles, but the number ingested was approximately one-half that of prefreeze values. Thawed cells also demonstrated superoxide anion synthesis at rates approximating those in unfrozen granulocytes. These results indicate that dog granulocytes obtained by leukapheresis may be preserved in liquid nitrogen at ?196 °C with high cellular recovery and at least 50% phagocytic function. 相似文献
4.
5.
R Welbourn G Goldman L Kobzik I Paterson C R Valeri D Shepro H B Hechtman 《Journal of immunology (Baltimore, Md. : 1950)》1990,145(6):1906-1911
Neutrophils and eicosanoid chemoattractants are centrally involved with ischemia-reperfusion (I/R) injury. The CD 18 complex of adhesive glycoproteins, readily up-regulated by chemoattractants in vitro, is required for polymorphonuclear leukocyte (PMN) adherence to endothelium. This study tests whether CD 18 is up-regulated by ischemia in vivo and its role in mediating PMN diapedesis. Anesthetized rabbits underwent 3 h of bilateral hindlimb tourniquet ischemia (n = 16). Ten min after tourniquet release, levels of plasma leukotriene (LT)B4 increased to 390 +/- 62 pg/ml (mean +/- SE), higher than 134 +/- 26 pg/ml in control rabbits (n = 13, p less than 0.01). Aliquots of plasma were added to whole blood from normal rabbits (n = 6) for flow cytometric analysis of neutrophils with the CD 18 mAb R 15.7. Addition of I/R plasma failed to demonstrate an increase in surface expression of CD 18. Similarly, no CD 18 up-regulation was observed in vivo upon reperfusion in ischemic animals pretreated with mAb R 15.7 (n = 3). However, I/R plasma when introduced into plastic chambers taped atop dermabrasion sites in normal rabbits (n = 12) resulted in diapedesis, measured by the accumulation after 3 h of 1130 +/- 125 PMN/mm3 in the chambers relative to 120 +/- 31 PMN/mm3 with control plasma (p less than 0.01). Diapedesis in response to I/R plasma was abolished by pretreatment with mAb R 15.7 (less than 5 PMN/mm3, n = 6), was reduced by U 75,302, an LTB4 receptor antagonist (253 +/- 101 PMN/mm3, n = 6) (both p less than 0.01) and was not protein synthesis dependent. These results demonstrate that PMN diapedesis in response to I/R plasma is exclusively dependent upon the CD 18 glycoprotein complex by an LTB4-dependent mechanism, despite the fact that CD 18 is not up-regulated on circulating PMN in ischemia. These data indirectly indicate the functional importance of conformational changes of CD 18 in determining PMN adhesion. 相似文献
6.
7.
Reactive oxygen species and elastase mediate lung permeability after acid aspiration. 总被引:10,自引:0,他引:10
G Goldman R Welbourn L Kobzik C R Valeri D Shepro H B Hechtman 《Journal of applied physiology》1992,73(2):571-575
Acid aspiration leads to increased neutrophil (PMN) oxidative metabolism, an event associated with lung leukosequestration and permeability increase. Neutropenia protected the vascular barrier function against acid injury. This study tests whether active oxygen species and elastase (which are presumably released by adherent PMNs) affect the microvascular barrier. Anesthetized rats underwent tracheostomy and insertion of a cannula into a lung segment. This was followed by localized instillation of 0.1 N HCl (n = 18) or saline (n = 18). Sequestration of PMNs in acid-aspirated and nonaspirated segments was 77 and 46 PMNs/high-power field (HPF), respectively, which was higher than control values of 11 and 8 PMNs/10 HPF in saline-aspirated and nonaspirated regions (P less than 0.05). Acid aspiration was associated with increased protein concentration in bronchoalveolar lavage (BAL) fluid to 3,550 and 2,900 micrograms/ml in the aspirated and nonaspirated lungs, respectively, which were higher than control values of 420 and 400 micrograms/ml (P less than 0.05). Acid aspiration also led to increased lung wet-to-dry weight ratios (W/D) of 6.6 and 5.4, which were higher than control values of 3.4 and 3.3 (P less than 0.05). Intravenous treatment of rats (n = 18) 90 min after aspiration with scavengers of reactive oxygen species, superoxide dismutase (1,500 U/kg), and catalase (5,000 U/kg), both conjugated to polyethylene glycol, did not reduce PMN sequestration but attenuated acid aspiration-induced increase in protein accumulation in BAL fluid in the aspirated and nonaspirated segments (990 and 610 micrograms/ml) as well as the increased lung W/D (4.6 and 4.0; all P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
M A Arnaout F W Luscinskas F J Lionetti C A Alper C R Valeri 《Journal of immunology (Baltimore, Md. : 1950)》1981,127(1):278-281
Fluorescent particles (Fluolite) with an average size of 0.1 micrometers were ingested by human granulocytes after incubation in fresh normal human serum (NHS). Ingestion was assessed by visual counting in a fluorescent microscope of cells containing particles. Ingestion required fresh normal serum and did not occur when serum was heated for 30 min at 50 degrees C or in the presence of ethylenediaminetetraacetic acid (EDTA). It did not occur in serum genetically deficient in C3b inactivator or in C3. Phagocytic activity was restored to C3-deficient serum by purified human C3 and to heat inactivated serum by purified factor B. Opsonic activity was present in NHS containing 5 mM Mg++ and 10 mM ethyleneglycoltetraacetic acid (EGTA) and in human serum genetically deficient in human C components C2 and C5. Agammaglobulinemic sera had normal opsonic activity. Opsonization of particles in this system is mediated through the alternative pathway of C activation, and its measurement serves as a simple quantitative functional assay for this system. 相似文献
9.
Evgenii Kliuchnikov Artem Zhmurov Kenneth A. Marx Alex Mogilner Valeri Barsegov 《PLoS computational biology》2022,18(6)
We introduce a Stochastic Reaction-Diffusion-Dynamics Model (SRDDM) for simulations of cellular mechanochemical processes with high spatial and temporal resolution. The SRDDM is mapped into the CellDynaMo package, which couples the spatially inhomogeneous reaction-diffusion master equation to account for biochemical reactions and molecular transport within the Langevin Dynamics (LD) framework to describe dynamic mechanical processes. This computational infrastructure allows the simulation of hours of molecular machine dynamics in reasonable wall-clock time. We apply SRDDM to test performance of the Search-and-Capture of mitotic spindle assembly by simulating, in three spatial dimensions, dynamic instability of elastic microtubules anchored in two centrosomes, movement and deformations of geometrically realistic centromeres with flexible kinetochores and chromosome arms. Furthermore, the SRDDM describes the mechanics and kinetics of Ndc80 linkers mediating transient attachments of microtubules to the chromosomal kinetochores. The rates of these attachments and detachments depend upon phosphorylation states of the Ndc80 linkers, which are regulated in the model by explicitly accounting for the reactions of Aurora A and B kinase enzymes undergoing restricted diffusion. We find that there is an optimal rate of microtubule-kinetochore detachments which maximizes the accuracy of the chromosome connections, that adding chromosome arms to kinetochores improve the accuracy by slowing down chromosome movements, that Aurora A and kinetochore deformations have a small positive effect on the attachment accuracy, and that thermal fluctuations of the microtubules increase the rates of kinetochore capture and also improve the accuracy of spindle assembly. 相似文献
10.
Valeri B. Kozhemyako Galina N. Veremeichik Yuri N. Shkryl Svetlana N. Kovalchuk Vladimir B. Krasokhin Valeri A. Rasskazov Yuri N. Zhuravlev Victor P. Bulgakov Yuri N. Kulchin 《Marine biotechnology (New York, N.Y.)》2010,12(4):403-409
Silicatein genes are known to be involved in siliceous spicule formation in marine sponges. Proteins encoded by these genes,
silicateins, were recently proposed for nanobiotechnological applications. We studied silicatein genes of marine sponges Latrunculia oparinae collected in the west Pacific region, shelf of Kuril Islands. Five silicatein genes, LoSilA1, LoSilA1a, LoSilA2, and LoSilA3 (silicatein-α group), LoSilB (silicatein-β group), and one cathepsin gene, LoCath, were isolated from the sponge L. oparinae for the first time. The deduced amino acid sequence of L. oparinae silicateins showed high-sequence identity with silicateins described previously. LoCath contains the catalytic triad of amino acid residues Cys-His-Asn characteristic for cathepsins as well as motifs typical for
silicateins. A phylogenetic analysis places LoCath between sponge silicateins-β and L-cathepsins suggesting that the LoCath gene represents an intermediate form between silicatein and cathepsin genes. Additionally, we identified, for the first time,
silicatein genes (AcSilA and AcSilB) in nonspicule-forming marine sponge, Acаnthodendrilla sp. The results suggest that silicateins could participate also in the function(s) unrelated to spiculogenesis. 相似文献