Ghost cell

Cells containing Hb-F are densely stained with erythrosln and cells with Hb-A appear as ghost cells Intermediate cells are stained more or less pink. Reticulocytes with Hb-A sometimes resemble Intermediate cells and may also show some Intracellular granulation. Inclusion bodies are visible In eluted cells as compact particles of differing sizes. Figure 10 gives some examples. The method Is Ideally suited to demonstrate the presence of newborn red cells In the maternal circulation. The method Is also widely used for the evaluation of the distribution of Hb-F within red cells mainly to differentiate between the HPFH condition and the 3 or 36 thalassemias. Evaluation of F cell smears In such cases Is difficult the term "equal distribution" usually Indicates the presence of Hb-F In each red cell but not necessarily In the same amount. 

Polymerizable lipids can be incorporated into e.g. erythrocyte ghost cells by means of hemolysis and polymerized here-... 

Woon, L.A., Holland, J.W., Kable, E.P. and Roufogahs, B.D., 1999, sensitivity of phospholipid scrambhng in human red cell ghosts. Cell Calcium, 25 313-320. 

First, a mixture of synthetic or natural phospholipids, polymerizable lipids, and proteins can be converted to liposomes and then be polymerized. Second, polymerizable lipids are introduced into e.g. erythrocyte ghost cells by controlled hemolysis and subsequent polymerization as described by Zimmermann et al.61). This hemolysis technique is based on a reversible dielectric breakdown of the cell membrane. Dielectric breakdown provides a third possible path to the production of bi omembrane models. Zimmermann et al. could show that under certain conditions cells can be fused with other cells or liposomes61). Thus, lipids from artificial liposomes could be incorporated into a cell membrane. A fourth approach has been published by Chapman et al.20). Bacterial cells incorporate polymerizable diacetylene fatty acids into their membrane lipids. The diacetylene units can be photopolymerized in vivo. The investigations discussed in more detail below are based on approaches 1. and 3. 

Figure 1. SEM of a typical ghost cell. Cells were deposited on a polycarbonate membrane (Nuclepore) whose pores are visible. The small white marker lines represent 1 xm.

In addition to SEM, size analysis of the ghost cells was performed with a Coulter counter, and as shown in Figure 2, the size distribution is similar to that of the washed red cell preparation. 

Figure 2. Distributions of cell volumes of typical red cell and ghost cell preparations, obtained by Coulter counter. Key to mean cell volumes red cells, 87 ixm3 and ghost cells, 76 ixm3.

SDS-PAGE of Adsorption Media. SDS-PAGE of various media used in this study was undertaken to obtain additional information on their protein compositions. Typical gels are presented in Figure 9. Gel 3 corresponds to the proteins from ghost cell membranes and shows a complex pattern of bands that agrees well with previously published results, for example, those of Fairbanks et al. (21). 

Figure 8. Adsorption of fibrinogen on glass in the presence of ghost cells. Conditions buffer—PBS, pH 7.35 and fibrinogen concentration—1.0 mglmL in free volume. Values are the average of three experiments. Key 0> ghosts at 15% HCT , ghosts at 45% HCT and —, level in absence of ghosts.

The results with ghost cells suggest that the membranes play a key role in the red cell effect. This point of view is in accord with conclusions from... 

In cell culture systems, normally only one cell type exists, and this precludes any natural defense by an active immune system and/or the interaction vith other cell types. There is a lack of systemic interaction and no provision for circulation. In addition, laboratories mostly use established cell lines vhich have reduced physiological responses that is, vith decreased enzyme activities and energy production and which may, under certain circumstances, be considered as ghost cells (Hildebrand and Hornez 1998). 

Flow Cytometer Lab-on-a-Chip Devices, Fig. 6 Micromachined impedance flow cytometer (a) side schematic view of the microchannel showing a particle passing over three electrodes (A, B, and C). The impedance signal is measured differently (Zac - Zbc). As the distance between two measurement areas and time separating the signal spikes are known, the speed of the particle can be calculated, and (b) signal in-phase amplitude of 2,000 erythrocytes and ghost cells recorded simultaneously for two frequencies [9]... 

Ghost cell glaucoma after intravitreal bevacizumab for postoperative vitreous hemorrhage following vitrectomy for proliferative diabetic retinopathy was identified in three of eight eyes in a retrospective chart review [8 ]. 

It involves the preservation of the contours of the coagulated cells. Appearance of ghost cells is shown in Fig. 4.43. 

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