Kinetics of rouleaux formation using TV image analyzer. II. Rat erythrocytes

With the use of a rheoscope combined with a TV image analyzer, the kinetics of specific pathogen-free rat erythrocyte aggregation was studied. Under certain conditions (gamma 7.5 s-1, hematocrit 0.36%, in own plasma, at 25 degrees C) one-dimensional aggregates (rouleaux) were formed without the development of three-dimensional aggregates, perhaps because of very low concentration of gamma-globulin. The observed phenomena could be explained by 1) the erythrocyte sedimentation and 2) the rouleaux formation. The time courses, of the biphasic change in erythrocyte count and of the increments in total area and in the area/count, were successfully simulated by a kinetic model of linear polymerization, assuming a sedimentation rate constant and an association rate constant. Further, a Poissonlike distribution of the length of rouleaux was shown, as predicted theoretically on the basis of the same kinetic model.

Spatial and temporal pattern of postnatal proliferation of glial cells in the parietal cortex of the rat

Rats were injected with [3H]thymidine on different postnatal days (PD 0 approximately PD 16) and sacrificed after 6 h. Parietal cortices were embedded in epoxy resin and then semithin sections for autoradiography and ultrathin ones for electron microscopy were made alternately. On the day of birth (PD 0), about 70% of total labeled cells within the cortical gray, which were proved to be glial cells, were observed in the inner half of the cortical width. On PD 4, however, the intracortical distribution of labeled cells was reversed, i.e. about 70% of labeled cells were found in the outer half. Thereafter, on PD 6 and PD 8, no significant difference of the number of the labeled cells could be noted between the outer and the inner halves of the cortical gray. The pattern of glial proliferation in the parietal cortex of early postnatal rat thus showed an inside-out tendency, although not so distinctive as that of prenatal neurogenesis in the neocortex. Electron microscopy of the labeled cells revealed that on earliest days, they showed the condensation of nuclear chromatin and abundant free ribosomes, both suggesting the immaturity of cells, while, on later days, the nuclear chromatin became dispersed and free ribosomes decreased, indicating the progress of cellular differentiation as glial cells.

Kinetics of rouleaux formation using TV image analyzer. I. Human erythrocytes

An apparatus for determining the velocity of erythrocyte rouleaux formation was constructed, combining an inverted microscope, a transparent cone-plate viscometer, a TV image analyzer, and a computer. At lower shear rates, the overall process is the sedimentation and the rouleaux formation followed by the development of three-dimensional aggregates. The individual erythrocyte could be observed and the process was expressed by the time courses of the changes in the count and area of particles; taking the computed increment in the area/count, the rate of rouleaux formation could be estimated. The effects of shear rates, hematocrits, plasma proteins, and pH were quantified. The rate of rouleaux formation in autologous plasma increased by (1) lowering the shear rates (1.9 less than or equal to gamma less than or equal to 15 s-1),2) increasing the hematocrit (up to 0.6%), 3) adding human fibrinogen (up to 600 mg/dl) or gamma-globulin, and 4) increasing pH. The transformation to echinocytes or to stomatocytes decreased the rate of rouleaux formation. The pH effect was explained by the increase in mean corpuscular volume at lower pH rather than by the changes in the electrostatic repulsion or in the protein binding.

Resection of thorotrast-induced cholangiocarcinoma

We report a case of successful surgical treatment of cholangiocarcinoma caused by a long standing thorotrastosis. Thorotrastosis should be recognized as a preliminary stage of malignancy. If early diagnosis of the tumor can be made, treatment may be successful.

The influence of deformation of transformed erythrocytes during flow on the rate of oxygen release

The deoxygenation rates of transformed erythrocytes were compared with those of normal discocytes by both stopped-flow and continuous-flow methods. Echinocytic and spherostomatocytic transformations were induced by various anionic and cationic drugs, respectively, without altering the oxygen affinity of haemoglobin, the cell volume or the membrane fluidity. The echinocytic transformation reduced the deoxygenation rate at slow-flow velocities (50 cm/sec), as detected by the continuous-flow method. However, at higher flow velocities (150 cm/sec) the rate was similar to that seen in normal discocytes. A close correlation between the degree of echinocytosis, the retardation of deoxygenation rate and the increase of suspension viscosity were observed. Microscopic observation of flowing erythrocytes revealed that the echinocytes scarcely deformed at the slower flow velocity, but clearly deformed at the higher flow velocity to various shapes resembling the flowing discocytes. Transformation to spherostomatocytes had no effect on the deoxygenation rate, which was comparable with that of the discocytes, and even the higher flow force did not induce any deformation. The retarded deoxygenation and the increased viscosity of echinocytes was probably due to an augmented stagnant layer around the cells (i.e. an increase of the hydrodynamic effective volume); this layer was reduced when the echinocytes were deformed with increasing flow force.

A Golgi study of Bergmann glial cells in developing rat cerebellum

In order to examine the relationship between the Bergmann glial cells and the migrating granule cells, the postnatal development of the Bergmann glial cells in the rat cerebellum was analysed by a rapid Golgi method. In newborn rats where immature Purkinje cells occupied a rather thick zone (about 8 cells thick) between the thin molecular layer and the intermediate zone, immature Bergmann glial cells were recognized by the irregularly contoured somata situated within the deep part of the zone of Purkinje cells and by several perpendicular thin fibers (filiform fibers) which traversed the external granular layer (EGL) to terminate at the pial surface. After day 2 of the postnatal age (PD2), both somata and fibers of Bergmann glial cells showed gradual or fairly abrupt changes. The somata migrated upwards toward the molecular layer on PD2 and on PD4 were situated just beneath the Purkinje cells which had become arranged in a single layer. After PD6 the distance between the pial surface and the somata situated in the Purkinje cell layer and concomitantly the length of the Bergmann glial fibers, progressively increased in accordance with the thickening of the molecular layer. Between PD0 and PD8 the somata were irregularly contoured with short protoplasmic processes extending radially. After PD8 they gradually lost these short processes and became smooth. The Bergmann glial fibers were rather smooth with a few beady enlargements and tiny bud-like excrescences on their surface between PD0 and PD8. On PD12 the bushy expansions, characteristic of matured Bergmann glial fibers, suddenly increased in number on most fibers. After PD12 they continued to augment until PD25, when most fibers were entirely covered with the expansions. The number of fibers issuing from each Bergmann glial cell and entering the EGL increased postnatally reaching a peak on PD8, and then decreased gradually. These changes in the number of Bergmann glial fibers corresponded well with those in the number of external granule cells, suggesting the presence of developmental interactions between these two kinds of cells.

Spatial and temporal pattern of postnatal proliferation of Bergmann glial cells in rat cerebellum: an autoradiographic study

In order to examine the relationship between the Bergmann glial cells and the migrating granule cells, the development of the Bergmann glial cells in the rat cerebellum was studied with 3H-thymidine autoradiography. 3H-thymidine was injected intraperitoneally into rats on two days successively between days 2 and 21 of the postnatal age (PD2 and PD21). All animals were sacrificed on PD25 and the vermis of the cerebellum was embedded in epoxy resin. Semithin sections were cut sagittally for autoradiography. The labeling index of the Bergmann glial cells in lobules I, II, III, IV, V, VIa, VIII, IX, and X reached the peak on PD6-7, and in lobules VIb and VII on PD8-9. Moreover, the lobules could be divided into three groups according to the day when cumulative labeling indices reached 50% of the total ones (LI50): The early-developing group (LI50; PD4.4-5.2) contained lobules I, II, III, IV, and V, the intermediate group (LI50; PD5.3-6.1) lobules VIa, VIII, IX, and X, and the late-developing group (LI50; PD6.6-7.8) lobules VIb and VII. The regional gradient of LI50 in the Bergmann glial cells corresponded approximately to the regional gradient in the ratio of late-forming granule cells; that is, the later the LI50 of the Bergmann glial cells, the higher is the ratio of the late-forming granule cells. This suggests that an intimate relationship exists between these two kinds of cells.

Protective effect of alpha-tocopherol on the morphological and rheological changes of rat red cells

The effect of alpha-tocopherol on the rheological properties of rat red cells was studied. The suspension viscosity of red cells increased, as the alpha-tocopherol content in red cells decreased. The red cells gradually transformed to echinocytes in isotonic solution dependent on the alpha-tocopherol content. The unique correlations among the viscosity, the transformation, and alpha-tocopherol content were observed. It was shown that the increased suspension viscosity of alpha-tocopherol-deficient cells could have arisen from the difficulty of echinocytes to undergo high shear deformation. The possible mechanism is discussed.

Functional impairments of human red cells, induced by dehydroepiandrosterone sulfate

A study has been made on the incorporation of dehydroepiandrosterone sulfate (DHAS), one of the most abundant adrenal C-19 steroids, into human red cells, and of the resulting effects on red cell functions. 1. DHAS was incorporated into red cell membrane mainly by a partition mechanism: The apparent partition constant was small ([DHAS]cell/[DHAS]free = 1.34), indicating that DHAS in red cells would be easily removed by dilution. 2. At least part of the DHAS taken up was apparently bound to band 3 protein and thereby was able to inhibit the exchange of intracellular and extracellular SO4(2-) (Ki = 70 micro M). 3. Using a fatty acid spin label, it was established that the presence of DHAS in lipid bilayer of the membrane increased the acyl chain motion in the middle portion of the membrane. 4. DHAS induced echinocytosis of red cells. It is suggested that the increase in the viscosity of red cell suspension, the decreased deformability and the decrease in the deoxygenation rate of hemoglobin in the presence of DHAS probably reflect the presence of echinocytes. 5. In the presence of plasma proteins, the incorporation of DHAs into red cells was remarkably suppressed.

Decreased viscosity of human erythrocyte suspension due to drug-induced spherostomatocytosis

The effect of two cationic drugs (chlorpromazine and isoxsuprine) on the suspension viscosity of human erythrocytes were examined, comparing with the effect of anionic drugs. (1) As increasing the drug concentrations, the cationic drugs transformed the erythrocytes to stomatocytes, then to spherostomatocytes, while trinitrobenzene sulfonate, dehydroepiandrosterone sulfate and lysolecithin induced echinocytes, as well known. (2) The suspension viscosity decreased in parallel with the appearance of spherostomatocytes, but it increased in echinocytosis. (3) The membrane fluidity, measured by spin label method, was not a major determinant for the suspension viscosity in these cases, because of no systematic correlation. (4) The rheoscopic observation under shear force demonstrated that the spherostomatocytes deformed easily to ellipsoid with smooth cell surface, while the echinocytes less easily deformed to ellipsoid on which the small spikes persisted at higher shear. These distinct difference in deformed shape under high shear force could be related to the decreased suspension viscosity of spherostomatocytes. (5) In addition, the transformation to spherostomatocytes, thus the decreased viscosity, was primarily determined by the intramembraneous drug concentration.

A method for studying oxygen diffusion barrier in erythrocytes: effects of haemoglobin content and membrane cholesterol

1. In order to study the kinetics os the oxygen egress from human red cells in the 50 sec-20 min time range, an apparatus for measuring the oxygen dissociation process was constructed, combining a spectrophotometer with an oxygen electrode of quick response. 2. Starting from air-saturated haemolysate or red cell suspensions, the velocity of oxygen dissociation from oxyhaemoglobin (Vdiss) and of oxygen disappearance in the medium (Vobs) after addition of bakers' yeast (consuming the dissolved oxygen at the velocity of Vconsump) were recorded. A parameter (r) was defined as the ratio of two velocities, Vegress (the velocity of oxygen egress into the medium) and Vdiss, r identical to Vegress/Vdiss = (Vconsump -Vobs)/Vdiss. Vcomsump could be calculated by the Michaelis-Menten equation as follows, Vconsump = Vmax [O2]/(Km + [O2]), where Vmax was the maximal velocity of oxygen consumption of bakers' yeast. 3. The r value was always 1.0 for the haemolysate, but it was less than 1.0 for the normal red cells. Further, the oxygen dissociation curve of red cells obtained at higher Vmax was distorted, due to the non-equilibration between intra- and extracellular oxygen concentrations. 4. The r value was (i) independent of the amounts of the allosteric effectors (2,3-diphosphoglycerate and H+) but (ii) dependent on the haemoglobin contents and (iii) dependent on the amounts of the membrane cholesterol. Therefore, the r value reflected only the process of the oxygen diffusion but not the "chemical reaction' rate. The "barrier' of the oxygen diffusion decreased at lower haemoglobin contents, but increased at higher cholesterol contents in the membrane.

Convergence to genetically uniform state in stepping stone models of population genetics

We investigate continuous time stepping stone model. Extending the models treated in population genetics, we consider the system described by the following infinite dimensional stochastic differential equation, (see text in formula) which contains the effects of random sampling drift and a kind of stochastic fluctuation in selection. We obtain a necessary and sufficient condition for the system to converge to a genetically uniform state.

Functional restoration of ACD-blood by pyrodoxal 5'-phosphate

Successful application of pyridoxal 5'-phosphate (PLP) to restore the oxygen transport function of ACD-stored blood is described. PLP is readily incorporated into ACD-erythrocytes by both carrier-mediated transport (in which ATP may participate) and passive diffusion. Plasma proteins (up to 2.5%) and inorganic phosphate (up to 40 mM) do not affect the incorporation of PLP, though more than 25 mM inorganic phosphate is necessary for the maintenance of ATP levels. Increasing the PLP concentration and/or decreasing the packed cell volume in the medium, increases the incorporation of PLP. Incubation of erythrocytes with PLP at pH 7.0 is most suitable for incorporation of PLP and the maintenance of ATP levels. PLP incorporated into erythrocytes restores the oxygen transport function of the ACD-erythrocytes, though decreased haem--haem interaction is observed. A procedure for the clinical application of PLP-loaded erythrocytes is suggested.

Effect of cholesterol on human erythrocyte membrane. A spin label study

The effect of cholesterol on the membrane fluidity of human erythrocytes has been studied by electron spin resonance (ESR) spectroscopy, sensing the motion of androstane and fatty acid spin labeles in the cell membrane and in vesicles made from extracted phospholipids. 1. Androstane spin label (ASL) was incorporated from ASL-containing phospholipid vesicles into the erythrocyte membrane, essentially by a partition mechanism in proportion to their phospholipid contents. 2. On increasing the cholesterol or ASl content in the cell membrane, the spin label was gradually immobilized. 3. ASL motion in the cell membrane seemed to be primarily determined by the cholesterol/phospholipid molar ratio, regardless of the membrane protein-lipid interaction, as judged from the temperature effects on the ESR spectra of both membranes. 4. However, glutaraldehyde pretreatment induced considerable changes of the cholesterol-lipid interaction in the cell membrane, i.e., strong immobilization and cluster formation of ASL were observed.

Rheological and functional impairments in cholesterol-loaded human erythrocytes

Decreased deformability, slightly increased suspension viscosity and retarded oxygen egrees were observed in cholesterol-loaded, human erythrocytes. These functional changes resulted from the decreased membrane fluidity induced by cholesterol.