Erythrocyte Distribution Research Articles

Modelling the internal field distribution in human erythrocytes exposed to MW radiation

This paper studies the internal electric field distribution in human erythrocytes exposed to MW radiation. For this purpose, an erythrocyte cell model is exposed to linearly polarized electromagnetic (EM) plane waves of frequency 900 MHz and the electric field within the cell is calculated by using a finite element (FE) technique with adaptive meshing. The results obtained show the dependence of the induced electric field distribution on the main modelling parameters, i.e., the electrical properties (permittivity and conductivity) of the membrane and cytoplasm and the orientation of the cell with respect to the applied field. It is found that for certain orientations, the field amplification within the membrane of the erythrocyte shape cell can be higher than the one observed in an equivalent simple spheroidal geometry cell, commonly used in bioelectromagnetism. The present work shows that a better insight of the interaction of electromagnetic fields with basic biological structures is obtained when the most possible realistic cell shape is used.

Estimation of erythrocyte population state by the spherical index distribution

The densities of cell distributions by spherical index (SI) in erythrocyte populations from healthy adults and donors with endocrine pathologies were determined via the developed method. The investigation shows that this characteristic varies for different donors, thereby reflecting the erythrocyte population state of an individual donor. Individual distribution curves obtained from healthy donors are close to Gaussian and are characterized by smooth curve plot with one maximum. Cells distribution by SI in donors with endocrine pathologies has a polymodal character. Our research shows that the developed method for determining erythrocyte distribution density by SI is a sensitive and informative test for quantitative evaluation of an erythrocyte population state. Moreover, this characteristic has clear physical and physiological significance, because an erythrocyte shape is strongly conditioned by the cell age and influences the ability to pass through microcapillaries in blood circulation.

Visualization of erythrocytes in the zebrafish brain.

We found that erythrocytes of zebrafish have cytoplasmic peroxidase activity. Blood in the zebrafish brain was visualized using a standard peroxidase staining method after formaldehyde fixation. The erythrocytes in the brain were heavily stained, but neurons and glias were not stained at all. This easy method enables the distribution of erythrocytes in the whole brain to be determined, and enables the actual number of erythrocytes in each area in the brain to be calculated. The paths of major, thick blood vessels in zebrafish brain are similar to those in higher vertebrates, however, the distribution of thin blood vessels is different. We also found that the erythrocytes were unevenly distributed in the brain. For example, the density of erythrocytes in the surface layer of the tectum was more than 30-fold higher than in the deeper granular layer. Very few erythrocytes were found in bundles of axons like cranial nerves and the medial longitudinal fascicle. In general, fewer erythrocytes were found in areas near the ventricle, whereas many more were found closer to the surface of the brain. The distribution of erythrocytes in the brains of sleeping, awake and actively moving fish were compared. In the brains of sleeping fish, most of the erythrocytes were present in large vessels. This was not observed in brains of awake or actively moving fish. We found that the blood supply to motor neurons in the ventral horn of the spinal cord increased during active movement compared to that in awake or sleeping fish.

Recruitment of Lung Diffusing Capacity: Update of Concept and Application

Lung diffusing capacity (DL) for carbon monoxide (DLCO), nitric oxide (DLNO) or oxygen (DLO2) increases from rest to peak exercise without reaching an upper limit; this recruitment results from interactions among alveolar volume (VA), and cardiac output (q), as well as changing physical properties and spatial distribution of capillary erythrocytes, and is critical for maintaining a normal arterial oxygen saturation. DLCO and DLNO can be used to interpret the effectiveness of diffusive oxygen transport and track structural alterations of the alveolar-capillary barrier, providing sensitive noninvasive indicators of microvascular integrity in health and disease. Clinical interpretation of DL should take into account Q in addition to VA and hemoglobin concentration.

Iron supplementation in pregnancy--evidence and controversies.

Approximately 20% of women in industrialized countries have iron deficiency in pregnancy. This article focuses on the diagnostic problem of anemia and iron deficiency and discusses different strategies for iron supplementation in pregnancy. S-ferritin is commonly used to diagnose empty iron stores and is considered useful early in pregnancy as a diagnostic tool. Mean cellular volume (MCV), s-Fe and erythrocyte distribution width is too unspecific. Serum transferrin receptor (sTfR) is a relatively novel promising indicator of iron deficiency. Iron demands of the pregnant women are discussed as well as the dietary content of iron. Both beneficial and adverse effects of iron supplementation are outlined. It is not documented that supplementation has any substantial effect on birth weight or various complications in pregnancy. However, supplementation corrects the iron store and biochemical parameters of iron deficiency including hemoglobin concentration (Hb) and maintains the maternal iron stores in the puerperium. Recent literature also suggests that iron supply to the pregnant women may have beneficial effects on the iron content of neonates the first year of life.

Age and sex peculiarities of distribution of blood erythrocytes according to their electrophoretic mobility

Age and sex peculiarities of distribution of blood erythrocytes according to their electrophoretic mobility

Effects of NO inhalation on pulmonary leukocyte sequestration and blood volume in porcine endotoxaemia.

Sequestration and migration of activated neutrophils plays a major role in the pulmonary injury typical of septic shock and the adult respiratory distress syndrome. Inhaled NO may counteract alveolar-capillary damage attributed to activated neutrophils. The present study describes a method to directly demonstrate the effects of NO inhalation on endotoxin-induced sequestration of 99mTc-labelled leukocytes [As(t)] in the lungs of pigs. Prospective controlled study. Laboratory for experimental surgery at a university medical centre. Anaesthetised and ventilated pigs. To induce inflammatory shock 26 animals received a continuous endotoxin infusion. Thirteen animals inhaled NO from the start of the experiments, while 13 served as controls. In 13 animals from both groups, leukocytes were labelled in vitro and reinjected, while in the 13 others erythrocytes were labelled in vivo to provide corrections for changes in blood volume. The pulmonary distribution of 99mTc-labelled leukocytes or erythrocytes was studied dynamically for 180 min. After correction for changes in pulmonary and heart blood volume (PBV, HBV), leukocyte sequestration curves were generated. Endotoxin induced pulmonary vasoconstriction, reduced PBV, impaired oxygenation, and caused a maximum increase in As(t) of 30% in the lungs. NO inhalation attenuated pulmonary vasoconstriction and the reduction in PBV. The maximum increase in As(t) was reduced to 15% of baseline. Inhaled NO exerts its main vascular effects in the pulmonary microvasculature, the primary site of physiological neutrophil margination and pathological adhesion of activated leukocytes. Early use of NO inhalation may offer protection against the development of more lasting pulmonary failure in septic shock by reducing leukocyte sequestration in the lungs.

The Effect of Short-Term Cold Exposure on Risk Factors for Cardiovascular Disease

The aim of this study was to see if a short-term period of exposure to cold in young healthy subjects causes changes in hematological factors known to be associated with the promotion of thrombogenesis. Over a period of 48 hours, changes in the distribution of erythrocytes, granulocytes, and blood platelets, as well as several coagulation, inflammatory, and fibrinolytic parameters, were monitored in 11 young healthy male subjects following a short period (1 hour) of cold exposure (CE) (ambient temperature, 11°C) or exposure to thermoneutral conditions (ambient temperature, 26°C) in winter (November). The major findings were: (1) a CE-induced hemoconcentration as indicated by an increase in erythrocyte count (3.2% increase); (2) after appropriate adjustments for changes in hemoconcentration, a cold-induced mobilization of granulocytes (14.5% increase) and a cold-induced decrease in lymphocytes (7% decrease); (3) thromboxane B 2 release following endotoxin stimulation of whole blood was increased by 27.4% in the CE experiments; (4) diurnal rhythms were observed in granulocytes, blood platelets, middle plate volume, tissue plasminogen activator, and plasma activator inhibitor; and (5) CE caused no significant changes in lipopolysaccharide-induced tissue factor, nor in the blood coagulation factor VII or cytokines, interleukin-6, and tumor necrosis factor. It is concluded that short-term cold exposure in young healthy subjects initiates a mild inflammatory reaction and a tendency for an increased state of hypercoagulability.

Endogenous Nitric Oxide Acts as a Natural Antithrombotic Agent In Vivo by Inhibiting Platelet Aggregation in the Pulmonary Vasculature

Nitric oxide (NO) is a powerful vasodilator and an inhibitor of platelet aggregation in vitro. While the ability of NO to modulate vascular tone in vivo has been proven, only a few studies have assessed its platelet inhibitory activity in vivo. We have employed two complementary animal models of pulmonary platelet thromboembolism to assess the antithrombotic activity of endogenous NO in vivo. The inhibition of nitric oxide synthase (NOS) by L-NAME significantly potentiated while the administration of the NOS substrate L-arginine significantly reduced the accumulation of 111In-labelled platelets in the pulmonary vasculature of rabbits induced by intravenous collagen plus epinephrine. L-NAME or L-arginine did not, however, modify 111In-labelled erythrocyte distribution in lungs and phenylephrine had no effect on platelet accumulation following collagen + adrenaline, suggesting that the effects of L-NAME were not due to vasoconstriction but rather to a direct modification of platelet function. In mice, L-NAME significantly reduced the dose of collagen + adrenaline required to induce thromboembolic mortality, increased the fall in circulating platelets and increased the % of pulmonary vessels occluded by platelet thrombi. The effects of L-NAME were reversed by L-arginine but not by a dose of nicardipine exerting maximal vasodilatation. Phenylephrine did not potentiate collagen + adrenaline-induced mortality. In the pulmonary vasculature in vivo, endogenous NO inhibits collagen + adrenaline-induced aggregation and enhances platelet disaggregation. This natural modulator function of NO is exerted via a direct effect on platelets and not as a result of haemodynamic changes.

In vitro characterization of the erythrocyte distribution of methazolamide: a model of erythrocyte transport and binding kinetics.

The rate and extent of binding of methazolamide to human erythrocytes was studied in vitro. All experiments were carried out at physiological temperature (37 C) and pH (7.4). Methazolamide (MTZ) buffer concentrations were analyzed by HPLC. Distributional equilibrium between buffer and washed red blood cells was achieved after 1 hr. Results of equilibrium studies were consistent with two classes of binding sites for MTZ within the erythrocyte: a low affinity, high capacity site (CA-I) and a high affinity, low capacity site (CA-II). A two-binding site model was fitted to experimental data generating estimates for binding parameters Ka1 (0.0017 +/- 0.00022 microM-1) nM1 (636 +/- 5.23 microM), Ka2(0.46 +/- 0.0083 microM-1), and nM2(80.9 +/- 0.389 microM). Based upon these findings, kinetic studies were performed in order to characterize the rate of drug distribution. The rate of erythrocyte uptake of MTZ was mathematically modeled using a series of differential equations describing drug diffusion across the red blood cell membrane and subsequent complexation with intracellular binding sites. The model assumed that penetration of MTZ into the red blood cells was passive but drug binding to the carbonic anhydrase isozymes was not instantaneous. Using a novel curve fitting technique, parameter estimates of RBC membrane permeability (0.0102 +/- 0.000618 cm/min), and binding rate constants k-1(0.254 +/- 0.0213 min-1), k1 (0.0022 +/- 0.00020 ml/microgram-min), k-2(1.59 +/- 0.0358 min-1), and k2(3.1 +/- 0.035 ml/microgram-min) were obtained. The model characterized the observed biphasic decline of MTZ buffer concentrations over time and may help explain the prolonged residence of MTZ in vivo.

Plasma and blood lead in humans: capacity-limited binding to delta-aminolevulinic acid dehydratase and other lead-binding components.

In 42 lead-exposed workers (22 male and 20 female), we found a close nonlinear relation between blood and plasma lead concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS). The concentration medians and ranges were lead in whole blood, 270 (97 to 950) micrograms/L and lead in plasma, 1.1 (0.2 to 13) micrograms/L. Proteins from lysed erythrocytes were studied by gel chromatography with ICP-MS detection. We then found capacity-limited binding for lead to delta-aminolevulinic acid dehydratase (ALAD), as well as to two other components (with apparent molecular masses of 45 and < 10 kDa, respectively). The strongest affinity for lead was indicated for ALAD (35-81% of the lead in blood) and could be described by a capacity of 850 micrograms/L and a dissociation constant of 1.5 micrograms/L. The 45-kDa protein carried 12-26% of the blood lead, and the < 10-kDa component less than 1%. A model based on these three components, plus a fourth one for unrecovered lead (2-45%), is proposed. No binding of lead to hemoglobin was found. There was an association between zinc and lead in whole blood; however, zinc did not significantly affect the lead distribution in erythrocytes.

Evaluation of piglet blood utilizing the Technicon H*1.

The analytic precision of an automated blood analyzer, the Technicon H*1(R), was evaluated utilizing blood samples collected from 20 piglets at 1 and 14 days of age. The effect of storing the blood samples at 4 degrees C for 24 and 48 hours also was determined. Blood samples were analyzed twice on the first day and once on each of the subsequent tow days. Within-sample coefficient of variation was approximately 1% for hemoglobin concentration, erythrocyte count, hematocrit, mean cell volume, erythrocyte distribution width and hemoglobin distribution width (HDW); and approximately 5% for total leukocyte (WBC), neutrophils and lymphocyte counts. Mean HDW and automated differential WBC counts changed during storage to a degree that could be of clinical importance. Manual determination of differential WBC counts were compared with those obtained from the automated analyzer. Results correlated well for neutrophils (r=0.92 in 1-day-old and r=0.93 in 14-day-old piglets, P<0.001) and lymphocytes (r=0.85 in 1-day-old and r=0.93 in 14-day-old piglets, P<0.001). Other WBC values were too low to compare reasonably.

Heterozygosity for the C282Y mutation in the hemochromatosis gene is associated with increased serum iron, transferrin saturation, and hemoglobin in young women: a protective role against iron deficiency?

Genetic hemochromatosis (GH) is the most common autosomal-recessive disorder (1 in 300 in populations of Celtic origin). Homozygosity for a C282Y mutation in the hemochromatosis (HFE) gene is the underlying defect in approximately 80% of patients with GH, and 3. 2-13% of Caucasians are heterozygous for this gene alteration. Because the high frequency of this mutation may result from a selection advantage, the hypothesis was tested that the C282Y mutation confers protection against iron deficiency in young women. To address this question the genotype of codon 282 was determined in a cohort of 468 unrelated female healthcare workers, ages 18-40 years. In all study participants, a complete blood count was obtained, and erythrocyte distribution width, serum iron, transferrin, transferrin saturation, and ferritin were measured. Two individuals were homozygous for the C282Y mutation, 44 were heterozygous, and 416 were homozygous for the wild-type allele. Heterozygous women had significantly higher values for hemoglobin (P = 0.006), serum iron (P = 0.013), and transferrin saturation (P = 0. 006) than women homozygous for the wild-type allele. Our data provide evidence for a protective role of the C282Y mutation in the HFE gene against iron deficiency in young women and suggest that a more efficient utilization of nutritional iron may have contributed to the high prevalence of the mutation in Caucasian populations.

Blood disposition and urinary excretion kinetics of methazolamide following oral administration to human subjects

The pharmacokinetic disposition of methazolamide (MTZ) was studied in five healthy volunteers following administration of a single oral dose. Drug concentrations in blood, plasma, and urine were measured by HPLC. Over the range of plasma concentrations observed in vivo, MTZ free fraction (measured by ultrafiltration) was 0.28. Being a carbonic anhydrase inhibitor, MTZ would be expected to distribute into, and be sequestered by, red blood cells. For this reason, MTZ disposition was characterized utilizing blood concentrations as the reference. Using a two-compartment model, a series of differential equations were simultaneously fitted to blood concentrations and urinary excretion data generating estimates for k10 (0.035±0.019 h−1), k12 (0.200±0.036 h−1), k21 (0.077±0.046 h−1), ka (0.304±0.064 h−1), Vc (1.1±0.18 L) and fr (fraction excreted renally, 0.61±0.14). Total blood clearance was 0.037±0.020 L h−1. The model estimate of elimination half-life (126±61 h) was consistent with drug binding to a high affinity carbonic anhydrase isozyme in the erythocyte. Estimates of MTZ renal clearance and renal excretion ratio were 0.021±0.010 L h−1 and 0.16±0.06, respectively. Overall, the prolonged elimination of MTZ from the blood is the result of extensive erythrocyte distribution and tubular reabsorption by the kidney. © 1998 John Wiley & Sons, Ltd.

Determination of the content of nonfilterable cells in erythrocyte suspensions as a function of the medium osmolality

The results of most filtration assays for deformability of erythrocytes do not distinguish whether the entire population or only its small fraction exhibits abnormal Theological properties. We developed a simple filtration method for determination of the percentage of nonfilterable cells in erythrocyte suspension using membrane filters with mean pore diameter of 3.1 μm. This method makes it possible to detect even minor abnormal subpopulations in erythrocyte suspensions. The flow rate of buffer depends on the number of free pores of a filter. The plot of the number of pores clogged by nonfilterable cells vs the total number of erythrocytes that were allowed to pass through the filter had a linear portion, with a slope representing the relative content, Z%, of nonfilterable cells in the suspension. We determined Z% for various medium osmolalities u and used the data to derive the distribution of erythrocytes in u cr ( u cr is the maximum value of u at which an erythrocyte cannot pass through a pore of a given filter because of geometric limitations). The distribution of u cr in suspension of normal erythrocytes has a ma×imum of about 200 mOsm/kg and a half-width of about 20 mOsm/kg. The distributions of u cr are altered in normal erythrocyte suspensions at decreased pH values, in cryopreserved and ATP-depleted erythrocyte suspensions and in erythrocytes from a xerocytosis patient.

The Effect of Peroral Administration of Amino Acid-Chelated Iron to Pregnant Sows in Preventing Sow and Piglet Anaemia

Two trials were performed in 2 different pig herds. In Trial 1, 9 pregnant Norwegian landrace sows were given a supplement in the feed of about 300 mg iron daily as amino acid-chelated iron (Bio-plex) during the last 3 weeks of gestation. Ten sows were included as controls. In Trial 2, 10 sows were fed a supplement of about 650 mg iron daily as glutamic acid-chelated iron (Super Fe-MAX) during the same period of pregnancy as in Trial 1. Twenty-two sows were included as controls. Blood samples were taken from the sows at the start of the experiment and on the day after parturition. The sows in Trial 1 were also bled at weaning 5 weeks after parturition. The piglets were weighted and blood samples collected 24 +/- 12 h after birth. Livers were taken from 65 piglets, which were either still-born or which died or were euthanised as one-day olds, and examined for iron content. The erythrocyte count (RBC), haemoglobin concentration (HGB), mean cell volume (MCV), erythrocyte distribution width (RDW), and haemoglobin distribution width (HDW) in blood were measured. Haematocrit (HCT), mean cell haemoglobin (MCH), and mean cell haemoglobin concentration (MCHC) were also estimated. Blood serum was analysed for total proteins, albumin, serum Fe, and total iron-binding capacity (TIBC). A slight increase in HGB and RBC in the piglets from the iron-treated sows compared with the controls was found in Trial 1, but this was considered to be of no practical importance. None of the other measured parameters were influenced by treating the pregnant sows with amino acid-chelated iron.

Plasma and Blood Lead in Humans: Capacity-Limited Binding to δ-Aminolevulinic Acid Dehydratase and Other Lead-Binding Components

In 42 lead-exposed workers (22 male and 20 female), we found a close nonlinear relation between blood and plasma lead concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS). The concentration medians and ranges were lead in whole blood, 270 (97 to 950) μg/L and lead in plasma, 1.1 (0.2 to 13) μg/L. Proteins from lysed erythrocytes were studied by gel chromatography with ICP-MS detection. We then found capacity-limited binding for lead to δ-aminolevulinic acid dehydratase (ALAD), as well as to two other components (with apparent molecular masses of 45 and <10 kDa, respectively). The strongest affinity for lead was indicated for ALAD (35–81% of the lead in blood) and could be described by a capacity of 850 μg/L and a dissociation constant of 1.5 μg/L. The 45-kDa protein carried 12–26% of the blood lead, and the <10-kDa component less than 1%. A model based on these three components, plus a fourth one for unrecovered lead (2–45%), is proposed. No binding of lead to hemoglobin was found. There was an association between zinc and lead in whole blood; however, zinc did not significantly affect the lead distribution in erythrocytes.

Cell age distribution of erythrocytes at the incidence of cerebral stroke in stroke-prone spontaneously hypertensive rats, and their glutathione peroxidase activity.

To study the mechanism of the fall of glutathione peroxidase (GSH-Px) activity in erythrocyte after cerebral strokes in stroke-prone spontaneously hypertensive rats (SHRSP), erythrocytes were fractionated into low density erythrocytes (LD-E) and high density erythrocytes (HD-E) by a density gradient centrifugal method using Percoll solution, and fluctuation of the distribution ratio and changes of GSH-Px activity in fractionated erythrocytes were investigated. The distribution ratio of LD-E and HD-E in erythrocytes of SHRSP was about 4:1 at 5 weeks of age (n = 6), and the distribution to HD-E increased along with aging. While the distribution ratio was changed, however, there was no change in the GSH-Px activity in both LD-E and HD-E of erythrocytes. In senile, 30-week-old SHRSP (n = 4) with advanced hypertension, the GSH-Px activity in the HD-E was lower, in proportion to the increase of the distribution rate against HD-E. On the other hand, in SHRSP (n = 5) having cerebral stroke, the distribution ratio of LD-E and HD-E was about 1:4. The GSH-Px activity was 31.4 +/- 2.9 units/10(10) erythrocytes in LD-E, which was hardly different from the value of SHRSP without stroke (35.7 +/- 3.3 units/10(10) erythrocytes). In HD-E, however, the activity was 18.2 +/- 2.2 units/10(10) erythrocytes, being lower than the activity of SHRSP without stroke. At the moment when the GSH-Px activity had dropped to 17 units/mg hemoglobin, and the control diet was changed to one based on fish or a hydralazine treatment given, the activity recovered, and an increase in body weight and the distribution rate of the LD-E over HD-E was increased. It is clear from these experiments that the fall of erythrocyte GSH-Px activity observed after cerebral stroke is due to a decrease of LD-E and increase of HD-E, which has lowered activity. However, nothing definite is known on the relationship between the fall of GSH-Px activity in erythrocytes and disorder in cerebral tissue. It appears that the fall of the GSH-Px activity causes at least functional and structural changes in erythrocytes, which interfere with the delivery of oxygen to peripheral tissues, triggering oxidation stress in cerebral tissues.

Computerised multiparametric analysis from images of blood flow through frog mesenteric arterial bifurcation

A computerised multiparametric procedure is developed to analyse the images of blood flow through various locations of the mesenteric arterial bifurcation of frog. The data are recorded by a video microscopic system and, after digitisation and pre-processing, are analysed by an IBM PC/AT based image processing system to obtain erythrocyte and velocity distribution profiles by axial tomographic and image velocimetry techniques, respectively. The vessel radius, haematocrit, blood flow through main and branch arteries and flow separation zones are determined from the data by various analytical procedures. In contrast to the earlier techniques the data are obtained from the same location of the vessel and thus the variability in flow parameters is minimised.

Screening for hereditary spherocytosis by use of automated erythrocyte indexes

Objective: To determine whether the mean corpuscular hemoglobin concentration (MCHC) or other erythrocyte indexes, as determined by automated cell counters, remains a useful screening test for identifying patients with hereditary spherocytosis (HS). Methods: Erythrocyte indexes from 112 children with HS who had not undergone splenectomy were compared with those measured in an equal number of healthy, age-matched children. All indexes were derived from measurements obtained by aperture impedance. Results: Mean corpuscular hemoglobin concentration in the HS group was 35.9 gm/dl, significantly higher than in normal control subjects (34.3 gm/dl; p <0.001). Mean erythrocyte distribution width also was significantly higher in patients with HS (19.3 vs 12.6; p <0.001). The MCHC distinguishes individuals with HS, with an area under the receiver operating characteristic curve of 0.86. Although not disease specific, an erythrocyte distribution width >14 has 85% sensitivity and 97% specificity and an area under the receiver operating characteristic curve of 0.92. An MCHC >35 gm/dl has a sensitivity of 70% and a specificity of 86%. Combining the MCHC and erythrocyte distribution width increases the area under the receiver operating characteristic curve to 0.97. Specificity is 100% and likelihood ratio is infinite when both the MCHC and erythrocyte distribution width are elevated. Conclusions: The automated MCHC is an effective screening test to identify children with HS. An elevated erythrocyte distribution width adds additional specificity and is itself a powerful screening tool. The combination of the two tests is an excellent predictor for the diagnosis of HS. (J Pediatr;130:957-60)