Platelet subpopulations: External to invaginated plasma membrane surface area is constant, independent of size

1986 ◽  
Vol 41 ◽  
pp. 119
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Membrane Surface ◽  
Constant Independent ◽  
Membrane Surface Area ◽  
Plasma Membrane Surface

PLATELET EXTERNAL SURFACE MEMBRANE IS OSMOTICALLY DOUBLED IRRESPECTIVE OF SIZE OR SPECIES (HUMAN/BOVINE): DYNAMICS AND MEMBRANE SOURCES

1987 ◽  
Author(s):  
Mony M Frojmovic ◽  
Truman Wong ◽  
Jane Wylie ◽  
J G White
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Shape Change ◽  
Membrane Surface ◽  
Surface Membrane ◽  
Osmic Acid ◽  
Osmotic Swelling ◽  
Membrane Surface Area ◽  
Water Dilution ◽  
Plasma Membrane Surface

Osmotic swelling can double the external plasma membrane surface area of human platelets independently of size, proposed to recruit the open surface-connected canalicular system ((SCCS) (Thrombos. Res. Suppl. VI: 119, 1986). As bovine (B) platelets have been reported to lack SCCS, we compared osmotic swelling for B and human (H) cells. Addition of water to piatelet-rich-plasma (10-90% v/v) caused sequential shape change and osmotic spherocyte (OS) formation, analyzed for size and surface area changes from time-dependent phase-contrast videomicroscopic images. Selected samples were fixed and stained with tannic acid prior to osmic acid fixation for visualization of open SCCS by transmission electron microscopy. B platelets required 3-4x less water dilution of PRP than H platelets, with significant OS forming at 20% water addition. Continued water dilution converted 50% of platelets to OS, with maximally stable swelling and no significant lysis for bovine OS up to 60% dilution. Electron micrographs of unactivated discocytes (D) and of optimally-swollen OS showed open SCCS in human D not detectable in any of the swollen platelets, though granules, mitochondria and a small number of vesicles and vacuoles persisted; no evidence for any open SCCS was found for bovine D or OS, though the OS otherwise appeared similar to H-0S. Geometric measurements of D and nonlysed OS showed a stable, maximal 2.1±0.1 fold increase in external plasma membrane surface area with osmotic swelling, identical for different-sized H platelets (mean volume = 2.8-6.8 f1) or for B platelets (3.6 f1 ). B platelets show equal or greater sensitivity for ADP-induced activation as H platelets, with 2-fold slower maximal rates of recruitment in early aggregation. As osmotic swelling appears to primarily externalize SCCS in H platelets, the identical relative amounts of internal membrane externalized for B platelets is hypothesized to arise from an osmotically more labile, “closed”, and structurally simpler SCCS or from a distinct membrane source tnan in H platelets.

scholarly journals Correlation of Na+,K+-ATPase content and plasma membrane surface area in adapted and de-adapted salt glands of ducklings

1985 ◽  
Vol 78 (1) ◽  
pp. 233-246 ◽  
Author(s):  
J.L. Merchant ◽  
D.S. Papermaster ◽  
R.J. Barrnett
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Salt Water ◽  
Membrane Surface ◽  
Salt Gland ◽  
Principal Cell ◽  
Membrane Surface Area ◽  
Principal Cells ◽  
Basolateral Plasma Membrane ◽  
Plasma Membrane Surface

During salt-water adaptation, an increase occurs in Na+,K+-ATPase content and surface area of the basolateral plasma membrane of the principal cell of the duck salt gland. To determine the degree to which these changes are correlated, accepted morphometric methods were used to determine numerical cell densities and plasma membrane surface densities of peripheral and principal cells. After adaptation, the plasma membrane surface area per principal cell was five times greater than in controls. Following de-adaptation, the plasma membrane content in principal cells returned to 1.9 times control levels. Two other cell constituents, mitochondria and lipid droplets, displayed similar quantitative changes. Na+,K+-ATPase content increased about fourfold with adaptation and decreased to near control levels with de-adaptation. Thus, changes in Na+,K+-ATPase content and basolateral plasma membrane surface area in adapting and de-adapting secretory epithelia of the salt gland occur nearly in parallel. These quantitative data enable Na+,K+-ATPase synthesis and degradation to be investigated in relation to membrane biogenesis.

scholarly journals Image Analysis Study of Aluminum Effects on Osmotic Behavior of Red Beet (Beta vulgaris L.) Protoplasts

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 899B-899
Author(s):  
Young Sang Lee ◽  
G Mitiku ◽  
A.G. Endress
Keyword(s):  
Image Analysis ◽  
Plasma Membrane ◽  
Membrane Surface ◽  
Biophysical Properties ◽  
Cross Sectional ◽  
Membrane Surface Area ◽  
Analysis Study ◽  
Red Beet ◽  
Osmotic Behavior ◽  
Plasma Membrane Surface

The hypothesis that Al3+ interferes with membrane biophysical properties has been tested. Plasma membrane expansion/contraction in protoplasts isolated from red beet was induced by decreasing or increasing the osmolarity of extracellular solutions. The percentage of Iysed protoplasts was measured to characterize the effects of Al3+ on the ability of protoplasts to increase their plasma membrane surface area. In control solutions (800 mM sorbitol), 31.4% of protoplasts Iysed following osmotic dilution from 1200 mM. Al3+ treatment (5 mM) decreased the proportion of Iysed protoplasts by 7.7% and Ca2+ (5 mM) by 17% compared to control. Lanthanum (La3+), however, proved to be the most efficient ion for protection against Iysis (3.3%). Under hypertonic solutions, Al3+ treatment helped protoplasts maintain their roundness, diameter, and cross-sectional area compared to the control (1.5 M sorbitol), thus, altering the protoplasts “roundness” as determined by image analysis parameters. The results suggest that a decrease in the proportion of Iysed protoplasts in the presence of Al3+ may be induced due to changes in membrane permeability to water.

EARLY EFFECTS OF THYROID STIMULATING HORMONE (TSH) ON EXOCYTOSIS AND ENDOCYTOSIS IN THE THYROID

1977 ◽  
Vol 86 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Lars E. Ericson ◽  
Bengt R. Johansson
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Membrane Surface ◽  
Follicle Cell ◽  
Thyroid Stimulating Hormone ◽  
Apical Plasma Membrane ◽  
Thyroid Follicle ◽  
Membrane Surface Area ◽  
Rat Thyroid ◽  
Stimulating Hormone

ABSTRACT The early effect (3 min) of thyroid stimulating hormone (TSH) on exocytosis-endocytosis in the rat thyroid follicle cell was investigated by electron microscopic morphometry. All rats used were pre-treated with thyroxine for 2 days prior to the experiments. In control rats, the membrane surface area of exocytotic vesicles, the only type of vesicle present in the apical part of the follicle cell, approximately equaled that of the apical plasma membrane. Intravenous administration of TSH caused a significant decrease in the membrane surface area of exocytotic vesicles by about 20 % and a corresponding, significant increase in the membrane surface area of the apical plasma membrane by about 20 %. Pseudopods were present in 4 of 6 TSH-injected rats examined, but the membrane surface area of these structures was only 15 % of the increase in the surface area of the apical plasma membrane. The total membrane surface area analyzed was not influenced by injection of TSH. We conclude that the initial effect of TSH on the thyroid follicle cell is a re-distribution of membrane from exocytotic vesicles to the apical plasma membrane. This conclusion is in harmony with our previous observations which indicate that the (membrane-requiring) endocytotic response after TSH is regulated by the amount of membrane material added to the apical plasma membrane by exocytosis.

The macrophage capacity for phagocytosis

1992 ◽  
Vol 101 (4) ◽  
pp. 907-913 ◽  
Author(s):  
G.J. Cannon ◽  
J.A. Swanson
Keyword(s):  
Surface Area ◽  
Membrane Surface ◽  
Fc Receptors ◽  
Phagocytic Capacity ◽  
Membrane Surface Area ◽  
Murine Bone Marrow ◽  
Latex Beads ◽  
Endocytic Compartments ◽  
Frustrated Phagocytosis

Murine bone marrow-derived macrophages, which measure 13.8 +/− 2.3 microns diameter in suspension, can ingest IgG-opsonized latex beads greater than 20 microns diameter. A precise assay has allowed the determination of the phagocytic capacity, and of physiological parameters that limit that capacity. Ingestion of beads larger than 15 microns diameter required IgG-opsonization, and took 30 minutes to reach completion. Despite the dependence on Fc-receptors for phagocytosis of larger beads, cells reached their limit before all cell surface Fc-receptors were occupied. The maximal membrane surface area after frustrated phagocytosis of opsonized coverslips was similar to the membrane surface area required to engulf particles at the limiting diameter, indicating that the capacity was independent of particle shape. Vacuolation of the lysosomal compartment with sucrose, which expanded endocytic compartments, lowered the phagocytic capacity. This decrease was reversed when sucrose vacuoles were collapsed by incubation of cells with invertase. These experiments indicate that the phagocytic capacity is limited by the amount of available membrane, rather than by the availability of Fc-receptors. The capacity was also reduced by depolymerization of cytoplasmic microtubules with nocodazole. Nocodazole did not affect the area of maximal cell spreading during frustrated phagocytosis, but did alter the shape of the spread cells. Thus, microtubules may coordinate cytoplasm for engulfment of the largest particles.

scholarly journals Paracrystalline arrays of membrane-to-membrane cross bridges associated with the inner surface of plasma membrane

1978 ◽  
Vol 77 (2) ◽  
pp. 323-328 ◽  
Author(s):  
WW Franke ◽  
C Grund ◽  
E Schmid ◽  
E Mandelkow
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Cultured Cells ◽  
Membrane Surface ◽  
Hexagonal Lattice ◽  
Interparticle Distance ◽  
Macromolecular Complexes ◽  
Inner Surface ◽  
Cross Bridges ◽  
Plasma Membrane Surface

In cultured cells of the rat kangaroo PtK2 line, veils of the cell surface were observed which consisted of only plasma membrane and paracrystalline arrays of membrane-associated particles sandwiched in between. These membrane-to-membrane cross-bridging 9-to 11-nm wide particles were somewhat coumellar-shaped and were arranged on a hexagonal lattice with an interparticle distance of 16nm. At higher magnification, they revealed an unstained core, thus suggesting a ringlike substructure. Similar arrays of paracrystal-containing veils, which were rather variable in size and frequency, were also observed in other cultured cells. It is hypothesized that these paracrystals represent protein macromolecular complexes associated with the inner plasma membrane surface which crystallize when plasma membranes come into close intracellular contact and other components of the subsurface network are removed.

scholarly journals Effect Of Surface Area Of Dialyzer Membrane On The Adequacy Of Haemodialysis

2012 ◽  
Vol 7 (2) ◽  
pp. 9-11 ◽  
Author(s):  
NS Chowdhury ◽  
FMM Islam ◽  
F Zafreen ◽  
BA Begum ◽  
N Sultana ◽  
...  
Keyword(s):  
Renal Disease ◽  
Surface Area ◽  
End Stage Renal Disease ◽  
Membrane Surface ◽  
Reduction Ratio ◽  
Urea Clearance ◽  
Membrane Surface Area ◽  
Stage Renal Disease ◽  
End Stage ◽  
Urea Reduction Ratio

Introduction: Patients with end stage renal disease require 12 hours of haemodialysis per week in three equal sessions (4 hours/day for 3 days/week). But the duration and frequency of treatment can be reduced by increasing the surface area of the dialyzer membrane. Methods: In this prospective study 40 patients of end stage renal disease receiving haemodialysis for more than six months were included to observe the effects of increment in the surface area of the dialyzer membrane on the adequacy of haemodialysis. Result: It was observed that 20 patients receiving haemodialysis on a dialyzer with membrane surface area of 1.2 m² did not have satisfactory solute clearance index. Urea reduction ratio was 45.9 ± 3.03 and fractional urea clearance (Kt/V) was 0.76 ± 0.09. On the other hand patients (20 cases) receiving haemodialysis on a dialyzer with membrane surface area of 1.3 m² had a urea reduction ratio 50.76± 5.16 and fractional urea clearance (Kt/V) 0.91 ± 0.16. All the patients of both groups received dialysis for 8 hours/week in two equal sessions (4 hours/day for 2 days/week). Statistically the increment was significant (p<0.001). Conclusion: This study reveals, adequacy of dialysis can be increased by increasing the surface area of the dialyzer membrane. So, considering the poor socioeconomic condition of Bangladesh and patients' convenience, a short duration, low cost dialysis regime can be tried by increasing the surface area of dialyzer membrane. DOI: http://dx.doi.org/10.3329/jafmc.v7i2.10387 JAFMC 2011; 7(2): 9-11

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