Fast transit of red cells and plasma in contracted versus relaxed spleens

1981 ◽  
Vol 59 (1) ◽  
pp. 53-58 ◽  
Author(s):  
M. J. Levesque ◽  
A. C. Groom
Keyword(s):  
Venous Pressure ◽  
Cell Movement ◽  
Red Cells ◽  
Flow Through ◽  
Flow Pathways ◽  
Volumes Of Distribution ◽  
Fast Pathway ◽  
Red Pulp ◽  
Injection Procedure

Nine-tenths of the inflowing blood passes through the normal relaxed spleen via a fast arteriovenous pathway whereas the remainder travels slowly via the red pulp. However, flow through this fast pathway diminishes to zero when the organ is distended by perfusion at high venous pressure. The present investigation, in which a slug-injection procedure was used to determine the volumes of distribution of red cells and 125I-labelled albumin in isolated, Ringer-perfused cat spleens during a single transit, has shown that in spleens contracted by noradrenaline the entire inflow passes via the fast arteriovenous pathway. The peak outflow concentration of 125I-labelled albumin occurred much later (factor 2.03) than that of red cells. This difference is too great to be accounted for solely by axial accumulation of red cells within a closed system of vessels in vivo and indicates that albumin was distributed throughout a significantly larger space than red cells. These findings are explained in terms of the classical observations of MacKenzie and co-workers on red cell movement in transilluminated mouse spleens during contraction. Whether the splenic retention of damaged red cells would change as a result of the altered flow pathways is not yet known.

pH environmental of red cells in the spleen

1976 ◽  
Vol 231 (6) ◽  
pp. 1672-1678 ◽  
Author(s):  
MJ Levesque ◽  
AC Groom
Keyword(s):  
Splenic Tissue ◽  
Red Cells ◽  
Red Cell ◽  
Cat Spleen ◽  
Flow Through ◽  
Red Pulp ◽  
Reduced Flow

Intrasplenic pH in vivo was deduced from measurements on blood drained from cat spleen during contraction with the inflow occluded. The pH of blood in the red pulp is normally 7.20, but stasis or reduced flow through the pulp causes pH to fall toward 6.8. The splenic pulp contains blood of high hematocrit. To evaluate the role of buffering by the red cells themselves, intrasplenic p/ in red cell-free spleens was, therefore, estimated atering and leaving the spleen during red cell washout. At inflow pH less than 6.8 the outflow pH was raised, at inflow pH = 6.8 there was no change, b,t at inflow pH greater than 6.8 the outflow pH was lowered. These results indicate that the pH environment of red cells in the spleen results indicate that the pH environment of red cells in the spleen results from the interplay of two separate factors: i) pH-determining elements of the splenic tissue that buffer at 6.8, and ii) buffering provided by red cells passing through the pulp.

scholarly journals Studies of the Hemopoietic Microenvironment. I. Changes in the Microvascular System and Stroma During Erythropoietic Regeneration and Suppression in the Spleens of CF1 Mice

Blood ◽  
1972 ◽  
Vol 39 (5) ◽  
pp. 697-712 ◽  
Author(s):  
Robert S. McCuskey ◽  
Howard A. Meineke ◽  
Samuel F. Townsend
Keyword(s):  
Bone Marrow ◽  
Blood Flow ◽  
Linear Velocity ◽  
Proliferating Cells ◽  
Hemopoietic Microenvironment ◽  
Murine Spleen ◽  
Flow Through ◽  
Tissue Compartments ◽  
Red Pulp

Abstract Specific alterations in the microvascular and connective tissue compartments of the hemopoietic microenvironment have been examined during erythropoietic regeneration and suppression in the murine spleen and bone marrow using in vivo microscopic and histochemical methods. The results have confirmed the concept of specific hemopoietic microenvironments and have demonstrated specific alterations in the microenvironment during erythropoietic stimulation and repression. Elevated erythropoiesis in the splenic red pulp is accompanied by an elevation in blood flow through the microvascular system. Both the linear velocity of flow and the number of sinusoids with blood flow in them increased significantly. In contrast, erythropoietic repression was accompanied by a decreased linear velocity of blood flow, as well as a marked increase in the amount of blood being stored in the splenic sinusoids. This also was the picture when diffuse granulopoiesis was present in the red pulp, or when granuloid or undifferentiated colonies were present. The chemical composition of the stroma in the spleen and bone marrow also varied during states of hemopoietic activity and, in addition, there were differences in the composition of the stroma between these two organs. In both organs, foci of early proliferating cells were enveloped by a coating of sulfated acid mucopolysaccharide. This coat persisted on cells in later stages of granulopoiesis but not on cells in the later stages of erythropoiesis. The latter were enveloped with a coating of neutral mucopolysaccharide. A tentative hypothesis to explain the mechanisms involved in producing these changes is discussed.

LACK OF EFFECT OF CORTICOSTEROIDS ON THE IN VIVO DISAPPEARANCE OF SULFHYDRYL-INHIBITED AND ANTIBODY-COATED ERYTHROCYTES

1964 ◽  
Vol 47 (3_Suppl) ◽  
pp. S28-S36
Author(s):  
Kailash N. Agarwal
Keyword(s):  
Red Cells ◽  
List Type ◽  
Red Cell

ABSTRACT Red cells were incubated in vitro with sulfhydryl inhibitors and Rhantibody with and without prior incubation with prednisolone-hemisuccinate. These erythrocytes were labelled with Cr51 and P32 and their disappearance in vivo after autotransfusion was measured. Prior incubation with prednisolone-hemisuccinate had no effect on the rate of red cell disappearance. The disappearance of the cells was shown to take place without appreciable intravascular destruction.

scholarly journals Hemolysis in the spleen drives erythrocyte turnover

Blood ◽  
2020 ◽  
Author(s):  
Thomas robert leon Klei ◽  
Jill Jasmine Dalimot ◽  
Benjamin Nota ◽  
Martijn Veldthuis ◽  
Erik Mul ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Matrix Proteins ◽  
Human Spleen ◽  
Erythrocyte Adhesion ◽  
Subsequent Degradation ◽  
Macrophage Subpopulations ◽  
Senescent Erythrocytes ◽  
Red Pulp

Red pulp macrophages of the spleen mediate turnover of billions of senescent erythrocytes per day. However, the molecular mechanisms involved in sequestration of senescent erythrocytes, their recognition and their subsequent degradation by red pulp macrophages remain unclear. In this study we provide evidence that the splenic environment is of substantial importance in facilitating erythrocyte turnover through induction of hemolysis. Upon isolating human spleen red pulp macrophages we noted a substantial lack of macrophages that were in the process of phagocytosing intact erythrocytes. Detailed characterization of erythrocyte and macrophage subpopulations from human spleen tissue led to the identification of erythrocytes that are devoid of hemoglobin, so-called erythrocyte ghosts. By in vivo imaging and transfusion experiments we further confirmed that senescent erythrocytes that are retained in the spleen are subject to hemolysis. Additionally, we show that erythrocyte adhesion molecules, which are specifically activated on aged erythrocytes, cause senescent erythrocytes to interact with extracellular matrix proteins that are exposed within the splenic architecture. Such adhesion molecule-driven retention of senescent erythrocytes, under low shear conditions, was found to result in steady shrinkage of the cell and ultimately resulted in hemolysis. In contrast to intact senescent erythrocytes, the remnant erythrocyte ghost shells were prone to recognition and breakdown by red pulp macrophages. These data identify hemolysis as a key event in the turnover of senescent erythrocytes, which alters our current understanding of how erythrocyte degradation is regulated.

scholarly journals NMDA Receptor Gating of Information Flow through the Striatum In Vivo

2008 ◽  
Vol 28 (50) ◽  
pp. 13384-13389 ◽  
Author(s):  
P. E. Pomata ◽  
M. A. Belluscio ◽  
L. A. Riquelme ◽  
M. G. Murer
Keyword(s):  
Nmda Receptor ◽  
Information Flow ◽  
Flow Through

scholarly journals Mechanisms responsible for F-actin stabilization after lysis of polymorphonuclear leukocytes.

1992 ◽  
Vol 116 (5) ◽  
pp. 1123-1134 ◽  
Author(s):  
M L Cano ◽  
L Cassimeris ◽  
M Fechheimer ◽  
S H Zigmond
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Actin Polymerization ◽  
Cell Movement ◽  
Actin Binding ◽  
Cross Linking ◽  
Macromolecular Complex ◽  
Actin Depolymerization ◽  
Gravitational Forces ◽  
End Capping

While actin polymerization and depolymerization are both essential for cell movement, few studies have focused on actin depolymerization. In vivo, depolymerization can occur exceedingly rapidly and in a spatially defined manner: the F-actin in the lamellipodia depolymerizes in 30 s after chemoattractant removal (Cassimeris, L., H. McNeill, and S. H. Zigmond. 1990. J. Cell Biol. 110:1067-1075). To begin to understand the regulation of F-actin depolymerization, we have examined F-actin depolymerization in lysates of polymorphonuclear leukocytes (PMNs). Surprisingly, much of the cell F-actin, measured with a TRITC-phalloidin-binding assay, was stable after lysis in a physiological salt buffer (0.15 M KCl): approximately 50% of the F-actin did not depolymerize even after 18 h. This stable F-actin included lamellar F-actin which could still be visualized one hour after lysis by staining with TRITC-phalloidin and by EM. We investigated the basis for this stability. In lysates with cell concentrations greater than 10(7) cells/ml, sufficient globular actin (G-actin) was present to result in a net increase in F-actin. However, the F-actin stability was not solely because of the presence of free G-actin since addition of DNase I to the lysate did not increase the F-actin loss. Nor did it appear to be because of barbed end capping factors since cell lysates provided sites for barbed end polymerization of exogenous added actin. The stable F-actin existed in a macromolecular complex that pelleted at low gravitational forces. Increasing the salt concentration of the lysis buffer decreased the amount of F-actin that pelleted at low gravitational forces and increased the amount of F-actin that depolymerized. Various actin-binding and cross-linking proteins such as tropomyosin, alpha-actinin, and actin-binding protein pelleted with the stable F-actin. In addition, we found that alpha-actinin, a filament cross-linking protein, inhibited the rate of pyrenyl F-actin depolymerization. These results suggested that actin cross-linking proteins may contribute to the stability of cellular actin after lysis. The activity of crosslinkers may be regulated in vivo to allow rapid turnover of lamellipodia F-actin.

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