Percentage Of Red Blood Cells Research Articles

Pretreatment Hematocrit Is Superior to Hemoglobin as a Prognostic Factor for Triple Negative Breast Cancer.

BackgroundAnemia usually refers to low hemoglobin (Hb) levels. Previous studies indicated that anemia negatively influence the survival in various cancers. Hematocrit (HCT) is the volume percentage of red blood cells in blood, which could indicate anemia in both individuals and populations. This study compared the value of HCT with that of Hb for predicting outcomes of patients who underwent treatment for triple negative breast cancer (TNBC).MethodsA retrospective study of 293 triple negative breast cancer patients, accepting treatment from January 2004 to December 2009 at Sun Yat-sen University Cancer Center, was conducted. Kaplan-Meier curves and multivariate Cox proportional models were used to calculate disease free survival (DFS) and overall survival (OS).ResultsThe cut-off value of HCT was 35.9% determined by X-tile software analysis. The cut-off value of Hb was 12.0 g/dl based on the World Health Organization (WHO) criteria. In univariate analysis, low HCT and low Hb were both significantly associated with decreased DFS and OS. In multivariate analysis, HCT (HR: 0.570; 95% CI: 0.331–0.981, P = 0.042 for DFS; HR: 0.456; 95% CI: 0.256–0.813, P = 0.008 for OS) was still identified as independent predictor of outcome, but not Hb.ConclusionPretreatment low HCT is independently associated with poor prognosis in TNBC patients. However, HCT was found to be superior to Hb in terms of predicting breast cancer mortality. In the future, large-scale prospective studies or validation studies are needed to verify our findings.

Blood component transfusion and wastage rates in the setting of massive transfusion in three regional trauma centers.

The purpose of massive transfusion protocols (MTPs) is to provide large quantities of blood products rapidly to exsanguinating patients. The expected rates of blood product transfusion and wastage in this setting have not been defined. This study was undertaken to assess the transfusion and wastage rates for bleeding patients requiring emergency issue of blood components at three American Level I trauma centers. Three hospitals participated, all of which are Level I trauma centers that have MTPs in place where uncrossmatched red blood cells (RBCs) can be ordered with or without platelets (PLTs), plasma, and cryoprecipitate. Data on the transfusion, return to blood bank, and wastage rates were recorded on all products issued within 3 hours after MTP activation. The majority of products were issued to the emergency department and/or operating room at all three institutions (84%-95%). The percentage of RBCs, plasma, and PLTs transfused during MTPs were 39% to 65%, 43% to 66%, and 75% to 100%, respectively. Wastage rates were comparable for RBCs (0%-9%), plasma (0%-7%), and PLTs (0%-7%). Cryoprecipitate had the highest wastage rates at all three sites (7%-33%). A large portion of blood products issued during MTPs are not transfused. Some are wasted due to stringent storage requirements and/or limited shelf lives. The optimum ratio of transfused to returned products in these patients is likely to be determined more by clinical need than by transfusion service policy.

Excessive quantities of red blood cells are issued to the operating room.

To determine what percentage of red blood cell (RBC) units that were issued to the operating room (OR) were returned unused, and to determine how often all of the RBCs that were issued for a patient were returned unused using the institution's maximum surgical blood ordering schedule (MSBOS) as a guide. The MSBOS provides guidelines for blood ordering, but is merely a suggestion for the ordering clinicians. This study examined how closely ordering practices followed the MSBOS, and how often ordered RBCs were actually transfused. For a 4-week period, RBC issue and utilization data were collected on elective surgery patients who were eligible for electronic cross-match at a tertiary care hospital. These data were compared to the MSBOS. There were 1350 surgical procedures performed. Of these cases, 439 patients had a type and screen (T&S) performed, and 215/439 (49%) patients had at least 1 RBC issued during their case. To these 215 patients, 742 RBC units were issued and 537/742 (72%) of these units were returned to the blood bank unused. In 152/215 (71%) cases with issued RBCs, all of the RBCs were returned to the blood bank unused. Amongst the surgical categories in this study, the percentage of cases where none of the issued RBCs were transfused ranged from 38 to 93%. Significant numbers of RBC units are issued but not transfused during surgery. Involving the surgical team in the blood issuing process and using a data-driven MSBOS may reduce the number of unused units.

Fragmented red cells reference range (Sysmex XN(®) automated blood cell counter).

Fragmented red cells (FRCs) is a new parameter automatedly determined by recent blood cell counters. Their count might be of interest because FRCs are supposed to reflect schistocytes counts measured on a stained peripheral blood smear observed under the microscope. But FRCs depend from the technical procedure used to detect them and thus reference ranges are device-dependent. The XN-9000(®) is one of the last model from Sysmex series. We aimed to establish reference range for FRCs, from 2389 controls. The mean ± SD was 0.32% ± 0.81, the median 0.02%(95% confidence interval ot the mean: 0.29-0.35%). We observed that the percentage of red blood cells with less than 17 pg of hemoglobin content (Hypo-He) was correlated to FRC increase, Hypo-He increase resulting in spurious FRCs majoration. FRCs reference range should be useful for: 1) laboratory staff in order to select which blood smears to check optically; 2) Sysmex company to set-up more optimal rules proposed with the counter (automated making of blood smear).

Hematocrit estimation using online sequential extreme learning machine.

Hematocrit is a blood test that is defined as the volume percentage of red blood cells in the whole blood. It is one of the important indicators for clinical decision making and the most effective factor in glucose measurement using handheld devices. In this paper, a method for hematocrit estimation that is based upon the transduced current curve and the neural network is presented. The salient points of this method are that (1) the neural network is trained by the online sequential extreme learning machine (OS-ELM) in which the devices can be still trained with new samples during the using process and (2) the extended features are used to reduce the number of current points which can save the battery power of devices and speed up the measurement process.

NK-, NKT- and CD8-Derived IFNγ Drives Myeloid Cell Activation and Erythrophagocytosis, Resulting in Trypanosomosis-Associated Acute Anemia.

African trypanosomes are the causative agents of Human African Trypanosomosis (HAT/Sleeping Sickness) and Animal African Trypanosomosis (AAT/Nagana). A common hallmark of African trypanosome infections is inflammation. In murine trypanosomosis, the onset of inflammation occurs rapidly after infection and is manifested by an influx of myeloid cells in both liver and spleen, accompanied by a burst of serum pro-inflammatory cytokines. Within 48 hours after reaching peak parasitemia, acute anemia develops and the percentage of red blood cells drops by 50%. Using a newly developed in vivo erythrophagocytosis assay, we recently demonstrated that activated cells of the myeloid phagocytic system display enhanced erythrophagocytosis causing acute anemia. Here, we aimed to elucidate the mechanism and immune pathway behind this phenomenon in a murine model for trypanosomosis. Results indicate that IFNγ plays a crucial role in the recruitment and activation of erythrophagocytic myeloid cells, as mice lacking the IFNγ receptor were partially protected against trypanosomosis-associated inflammation and acute anemia. NK and NKT cells were the earliest source of IFNγ during T. b. brucei infection. Later in infection, CD8+ and to a lesser extent CD4+ T cells become the main IFNγ producers. Cell depletion and transfer experiments indicated that during infection the absence of NK, NKT and CD8+ T cells, but not CD4+ T cells, resulted in a reduced anemic phenotype similar to trypanosome infected IFNγR-/- mice. Collectively, this study shows that NK, NKT and CD8+ T cell-derived IFNγ is a critical mediator in trypanosomosis-associated pathology, driving enhanced erythrophagocytosis by myeloid phagocytic cells and the induction of acute inflammation-associated anemia.

Fragmented red cells reference range for the Sysmex XN®-series of automated blood cell counters.

Fragmented red cells (FRCs) are a new parameter determined automatically by the latest generation of blood cell counters. FRC counts may be of interest as they may reflect schistocyte counts measured on a stained peripheral blood smear observed under the microscope. However, FRC counts depend on the technical procedure used to detect them so that reference ranges are device dependent. The XN-9000® is one of the latest models from the Sysmex series of analysers. We aimed to establish a reference range for FRCs based on 1366 normal patient samples. The mean ± SD was 0.14 ± 0.35% and the median was 0% (95% confidence interval of the mean: 0.12-0.16%). We observed that the percentage of red blood cells with <17 pg of haemoglobin content (Hypo-He) was correlated to an FRC increase and that flagged results relating to red blood cells, reticulocytes or platelets might have presented with artefactually increased FRCs. The FRCs reference range (healthy subjects) should be useful for laboratory staff for selecting which blood smears to check optically.

'Red blood transfusion in patients undergoing cardiac surgery'.

The use of allogeneic red blood cells (RBC) is commonplace in cardiac surgery, with reported transfusion rates ranging from 5 to 90 %. [1–4] Despite advantages, RBC transfusion is associated with well-described adverse outcomes. [1–4] Transfusion of RBCs is not only associated with an increased perioperative mortality and morbidity, however; it also results in a longer ICU stay, total hospital stay and increased costs. [2] Even the long-term results are influenced by perioperative RBC transfusions. Koch et al. found a significantly reduced 6-month and late survival in patients undergoing an isolated CABG with transfusion of RBCs. [1] Not only the question of RBC transfusion, but also the number of units of transfused RBCs and the method and duration of storage of RBCs is important. [3, 4] It is no surprise that several studies focus on blood conservation methods and a more judicious use of RBCs, with as prerequisite the identification of preoperative variables associated with an increased need for transfusion. [3, 4] Female gender, impaired left ventricular function, low preoperative haemoglobin, risk and complexity of the operation are the most identified variables with an increased risk for RBC transfusion [3, 4] However, even with the routine use of current blood conservation methods, a proportion of patients undergoing cardiac surgery continue to receive RBC transfusion and are hence exposed to its associated risk [1–4]. There is, therefore, an ongoing need to study further blood conservation methods. In their recent study, [5] Haanschoten et al. focus on reducing the immediate availability of RBCs in cardiac surgery. Since March 2010, the No Elective Red Cells (NERC) program is being used. The only change for their current study is that RBCs are now not directly available in the operating theatre and, when needed, the local blood bank can deliver the cross-matched RBCs within 20 min. So, the aim of this new strategy is to reduce the number of units of RBCs returned to the laboratory and certainly the numbers of those units that can no longer be used because of a reduced quality of the RBCs. This is of course an interesting point in the whole discussion of blood conservation, mostly evaluated only on the percentage of patients without RBC transfusion and /or the number of units transfused. The authors show that in a selected group of patients it is safe to perform cardiac surgery with the immediate availability of RBCs in the operating theatre. [5] Eighty-one percent of the patients did not receive any RBCs and the predictors for the need of blood transfusion are confirming the results of previous studies. [3, 4] However, some interesting points are not discussed in this study. Since the start of the NERC program, what was the percentage of RBCs returned to the blood bank and what was the percentage of units that could no longer be used because of reduced quality? It is emphasised that in all patients who need a blood transfusion, blood was available within 20 min after ordering it. However, was this really so? What was the time between ordering and delivering the blood in the operating theatre? What happens in cases of catastrophic bleeding problems, always possible even in the most simple cardiac procedure? These questions are essential before general conclusions can be made about safety and the effectiveness of this new strategy, no immediate availability of red blood cells, in the NERC program.

Proposed criterion for distinguishing ABO mosaics from ABO chimeras using flow cytometric analysis

Abstract Differentiation of ABO mosaics from chimeras is performed using flow cytometry (FCM) analysis. Although mosaics and chimeras have been distinguished by presence or absence of clear resolution using FCM analysis, the lack of quantitative metrics and definitive criteria for this differentiation has made some cases difficult to differentiate. In this study, therefore, we attempted to establish a definitive and quantitative criterion for this differentiation. When FCM histogram gates for group “A” or “B” antigen-negative and -positive red blood cells (RBCs) were set such that group O RBCs were classified as 99 percent negative and group A or B RBCs as 99 percent positive, the percentages of RBCs in the middle region of six chimeras and 23 mosaics (12 A mosaics and 11 B mosaics) were 0.1–0.6 percent and 7.0–19.0 percent, respectively. This result suggested that ABO mosaics and chimeras can be unambiguously differentiated when the cutoff point of the intermediate region is set to 1 percent. Immunohematology 2015;31:24–28.

Biochip technology applied to an automated ABO compatibility test at the patient bedside

In the field of blood transfusion, there is a need to improve the bedside pre-transfusion ABO compatibility test. In France, this test is mandatory for each red cell concentrates transfusion. It is performed manually and serious transfusion accidents still occur, principally due to human errors. Therefore, an automated ABO compatibility test is required. Works concerning objective interpretation of ABO compatibility test have been reported but the proposed techniques cannot be easily translated to the patient's bedside. We propose a prototype device which demonstrates the easy use of biochip technology to perform this test: it contains a fluidic system, biochips (two to test the patient and two to test the red cell concentrates) and an optical absorbance detection module. When blood is applied to the biochips, red blood cells are trapped onto the surface if antigens and antibodies are complementary (positive chips). If they are not complementary, very little red blood cells are adsorbed (negative chips). Percentages of surface covered with red blood cells in negative biochips are 2%±2 (red cell concentrates) and 1%±1 (whole blood). This proves that the fluidic configuration leads to an optimum control of fluids flows with little retention of red blood cells in the circuitry. These percentages increase to 96%±3 and 82%±8 for red cell concentrates and whole blood respectively. This demonstrates a strong and specific immunocapture of red blood cells on positive chips. Furthermore, optical detection proves to be efficient at critical red blood cells concentrations (108C/mL) and absorbance strongly correlates to the percentage of red blood cells captured by antibodies.

Histopathologic Composition of Cerebral Thrombi of Acute Stroke Patients Is Correlated with Stroke Subtype and Thrombus Attenuation

IntroductionWe related composition of cerebral thrombi to stroke subtype and attenuation on non-contrast CT (NCCT) to gain more insight in etiopathogenesis and to validate thrombus attenuation as a new imaging biomarker for acute stroke.MethodsWe histopathologically investigated 22 thrombi retrieved after mechanical thrombectomy in acute stroke patients. First, thrombi were classified as fresh, lytic or organized. Second, percentages of red blood cells (RBCs), platelets and fibrin and number of red, white (respectively RBCs or platelets outnumbering other components with ≥15%) or mixed thrombi were compared between large artery atherosclerosis (LAA), cardioembolism, dissection and unknown subtype. Third, correlation between attenuation and RBCs, platelets and fibrin was calculated using Pearson's correlation coefficients (r).ResultsThrombi were fresh in 73% (n = 16), lytic in 18% (n = 4) and organized in 9% (n = 2). The stroke cause was LAA in eight (36%), cardioembolism in six (27%), dissection in three (14%), and unknown in five (23%) patients. LAA thrombi showed the highest percentage RBCs (median 50 (range 35–90)), followed by dissection (35 (20–40), p = 0.05), cardioembolism (35 (5–45), p = 0.013) and unknown subtype (25 (2–40), p = 0.006). No differences in platelets (p = 0.16) and fibrin (p = 0.52) between subtypes were found. LAA thrombi were classified as red or mixed (both n = 4), cardioembolisms as mixed (n = 5) or white (n = 1) and dissection as mixed (n = 3). There was a moderate positive correlation between attenuation and RBCs (r = 0.401, p = 0.049), and weak negative correlations with platelets (r = −0.368, p = 0.09) and fibrin (r = −0.073, p = 0.75).ConclusionsThe majority of cerebral thrombi is fresh. There are no differences in age of thrombi between subtypes. LAA thrombi have highest percentages RBCs, cardioembolism and unknown subtype lowest. No relationship exists between subtype and platelets or fibrin percentages. We found a correlation between the RBC-component and thrombus attenuation, which improves validation of thrombus attenuation on NCCT as an imaging biomarker for stroke management.

Hydroxyurea Induces Genome-Wide Epigenetic Changes In Sickle Cell Disease

AbstractAbstract 2670 Introduction:Hydroxyurea (HU) is currently the only pharmacologic agent widely used to ameliorate the symptoms of sickle cell disease (SCD). The clinical effects of HU are diverse, including the well-known increase in levels of fetal hemoglobin (HbF), effects on leukocyte and platelet counts, and down-regulation of red cell adhesion despite increased expression of some adhesion receptors. However, the precise mechanisms by which HU exerts its ameliorative and pleiotropic actions are not well understood. HU is primarily thought to inhibit DNA replication and cause cell cycle arrest due to inhibition of ribonucleotide reductase (Yarbro, 1992). This mechanism is likely how HU exhibits its ameliorative effects in myeloproliferative conditions. But it is not as clear how this action results in an increase in the percentage of red blood cells that express a large percentage of HbF (Platt, 2008). Previous evidence suggests that HU may induce epigenetic (specifically, hypermethylation) changes to DNA (Nyce, 1989). Thus, we hypothesized that HU may increase HbF levels and cause other systemic changes through epigenetic mechanisms. Methods:To test the hypothesis that HU usage is associated with alterations in DNA methylation, we examined DNA samples from 24 adult patients with SCD, 12 of whom were taking HU at the time of DNA collection and 12 of whom were not. DNA from each individual was pre-treated with bisulfite (Zymo Research) and assessed for methylation levels at 27,578 CpG sites in 14,495 genes using the Illumina HumanMethylation27 BeadChip. One sample (off HU) failed to undergo a successful bisulfite DNA conversion and was subsequently removed from analysis. The relative levels of methylation (β) were calculated as the ratio of methylated probe signal to total locus signal intensity. Linear regression (PROC GLM, SAS version 9.1.3, Cary, NC) was used to test for differences in methylation (β) as a function of HU usage, controlling for sex and age. Results:On average, patients using HU had higher mean levels of methylation genome-wide compared with patients not taking HU, although the difference was not statistically significant, likely due to the small number of patients examined. Using the Benjamini-Hochberg false discovery correction for multiple testing and setting a stringent corrected p-value threshold of 0.05, we identified 247 out of the approximately 27,000 CpG sites that were differentially methylated as a function of HU usage. Eight CpG sites met a very stringent Bonferroni correction and represented a functionally diverse set of genes, including ones that encode a phosphatase, influence neural outgrowth, and play a role in vertebral development. CpG sites meeting the false discovery correction (n=247) were subsequently subjected to gene network and ontology analysis using DAVID pathway software (http://david.abcc.ncifcrf.gov/) to determine if specific biological pathways were statistically enriched for differences in DNA methylation. Several of these sites were associated with pathways involved in cell growth, senescence and differentiation, as might be expected given the known effects of HU on hematopoiesis. However, the TGFβ pathway was also significantly represented in this subset of CpG sites (pathway analysis p<0.05). Discussion:Consistent with findings by Nyce (1989), we observed a trend in which HU usage was associated with hypermethylation, so that patients taking HU had on average more methylation genome-wide than patients not taking HU. Genetic variation in the TGFβ pathway has been implicated in the occurrence of several SCD complications, including pulmonary hypertension (Ashley-Koch et al., 2008), risk for stroke (Sebastiani et al., 2005), leg ulcers (Nolan et al., 2006), bacteremia (Adewoye et al., 2006), and priapism (Elliott et al., 2007). Therefore, identification of this pathway as affected by HU is especially interesting. In summary, we have evidence that DNA epigenetic differences occur in sickle cell patients as a result of HU usage and are associated a wide variety of gene pathways, consistent with the diverse array of clinical and laboratory changes observed in patients on HU. Future studies will include confirmation of the epigenetic differences in the specific genes implicated among a larger cohort of SCD patients on and off HU, as well as functional studies of these genes. Disclosures:No relevant conflicts of interest to declare.

Hematological Parameters, Plasma Polypeptide Profiles, and Human Anti-Cancer Bioactivity of Testudo graeca and Testudo horsfieldii Plasma

We documented differential blood cell counts and plasma polypeptide profiles in Testudo graeca and T. horsfieldii raised in captivity in Lebanon, and investigated bioactivity of T. graeca plasma against a human colon cancer cell line (HCT-116). The percentage of red blood cells, thrombocytes, heterophils, basophils, lymphocytes, monocytes, and eosinophils did not differ significantly between the species during winter or spring. The total number of plasma polypeptides differed between the species, with 2 additional polypeptide bands in T. horsfieldii. Plasma from T. graeca significantly affected the percentage proliferation and percentage viability of human cancer cell line HCT-116.

Parasite density and the spectrum of clinical illness in falciparum malaria.

To determine the impact of percentage parasitemia and clinical features on morbidity and mortality in patients with P. falciparum malaria. Case series. Department of Medicine, Medical Unit II, Jinnah Postgraduate Medical Centre, Karachi, Pakistan from May to November 2005. Seventy-six adult patients of smear positive P. falciparum malaria were selected for the study. Parasite density was estimated on thin blood film and expressed as percentage of red blood cells parasitized. Patients were divided into three groups on the basis of parasite density. The data was analyzed on SPSS version 12. Results were expressed as percentages, mean and standard deviations. P-value <0.05 was taken as significant. Data of 76 study patients who fulfilled the inclusion criteria was analyzed on the basis of parasite density. Thirty-one (40.79%) patients had parasite density < 5%, 22 (28.95%) had parasite densities between 5% and 10% and 23(30.26%) patients had parasite density >10%. Comparative analysis of the groups showed that pallor, impaired consciousness, jaundice or malarial hepatitis, thrombocytopenia, acute renal failure, DIC, and mortality were all strongly associated with the density of Plasmodium falciparum malaria (p=0.001). Parasite density was not related to age, gender and hepatosplenomegaly. High parasite density was associated with severe clinical illness, complications and mortality. Parasite counts of > 5% may be considered as hyperparasitaemia in this population of the world.

Intake and productivity of lambs grazing leafy or stemmy forage rape and the effect of energy or protein supplements

Weaned lambs grazed forage rape in a leader-follower grazing system to create leafy and stemmy swards. Stemmy swards had a lower herbage mass and leaf content, a much higher stem and neutral detergent fibre content, and a lower N content. Lambs grazing both swards were given either no supplement or daily supplements of rolled barley (energy) or rolled barley plus formaldehyde-treated soyabean meal (protein). Half the lambs in one replicate were also given supplementary copper to counter possible effects of S-methyl-L-cysteine sulphoxide ingestion from the forage rape. The copper supplement had significant effects on liver copper content, plasma copper and the percentage of red blood cells with Heinz bodies, but there was no effect on liveweight gain compared with lambs which did not receive copper. Lambs grazing the stemmy sward ate less herbage, but much more of the supplements, in both absolute and proportional terms. Herbage intake was not influenced by supplement type. Substitution between herbage and supplement was low (&lt;0 to 12%) and not notably different between the crop types or supplements. Liveweight gains on the leafy crop (160–200 g/day) were higher than on the stemmy crop (114–143 g/day) with significantly higher gains in lambs given the protein supplement. Supplementation did not influence carcass weight or the rates of carcass protein or fat gain, which were all higher in lambs grazing the leafy crop. The results suggest that protein supplements may improve the liveweight gain of lambs grazing forage rape.

Identification and evaluation of major histocompatibility complex antigens in chicken chimeras and their relationship to germline transmission

Chimeric chickens were evaluated as an intermediate for development of transgenic chickens. The transfer of Barred Plymouth Rock (BR) blastodermal cells into White Leghorn (WL) embryos results in BR–>WL chimeras, and some breeder males generate over 30% germline transmission of the BR genotype to offspring based on a feather-color trait. The objectives of the current study were to 1) identify the MHC (B haplotypes) in resident BR and WL lines, 2) establish that B antigens could be detected and quantified in red blood cells (RBC) of chimeras, 3) establish if there is a correlation in chimeras between percentage of RBC with donor B antigens and percentage germline transmission, and 4) evaluate if the MHC genotype influences chimera development. The RBC agglutination data indicated three B haplotypes were present in each line. The B*2-like, and B*19-like genes were unique to the WL line, and B*13-like and B-15-like genes were unique to the BR line, whereas a B*21-like gene was present in both lines. In adult BR–>WL chimeras, as well as 10- to 14 d-old WL–>WL chimeras, donor-type B antigens were detectable and quantifiable on RBC using flow cytometry. In BR–>WL chimeras, the percentage germline transmission was significantly correlated with the percentage of RBC with donor B antigen, as well as percentage of black feathers in the plumage. In a retrospective study using previously developed BR–>WL chimeras, the level of chimerism and germline transmission was higher in B*21/*21 type recipients, but this was not statistically significant in two prospective studies. It was concluded that MHC antigens on RBC can be used for identifying, quantifying, and selecting chicken chimeras developed by the transfer of blastodermal cells.

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The human spleen during physiological stress.

Many mammals have the ability to autotransfuse a large quantity of red blood cells from the spleen into the active circulation during times of stress. This enhancement of the oxygen transport system has benefited the athletic mammal, that is, the thoroughbred horse, fox and greyhound in an improved aerobic performance. The role of the spleen in sequestering 50% of the total red cell volume in seals and horses, during times of inactivity, dramatically reduces the viscosity of the blood and therefore the work of the heart. In comparison, the human spleen contains only a small percentage of red blood cells, and has been primarily thought of as a lymphoid organ. The aim of this review is to emphasise the similarities between the human spleen and that of several athletic mammalian species during acute physiological stress. In the athletic mammalian model the expulsion of blood from the spleen is facilitated via the sympathetic nervous system resulting in contraction of smooth muscle within the splenic capsule. In comparison, the lack of smooth muscle contained within the human splenic capsule has meant that active contraction of the spleen has historically been viewed as unlikely, although evidence of contractile proteins within the red pulp have suggested otherwise. Exercise results in haemoconcentration, which has been attributed solely to a reduction in plasma volume. Indirect calculation of plasma volume changes utilise haemoglobin and haematocrit and assume that the circulating red cell volume remains constant. However, several studies have suggested that the human spleen could account for 30% of the increase in haematocrit. This would result in a substantial overestimation of the reduction in plasma volume, indicating that the expulsion of red blood cells from the spleen must not be overlooked when utilising these equations.

Anaemia of renal failure: Differences between continuous ambulatory peritoneal dialysis and haemodialysis

SUMMARY:A cross‐sectional study was performed to assess a series of parameters, especially those related to iron status, that may account for differences in the anaemia of patients treated with continuous ambulatory peritoneal dialysis (CAPD) and haemodialysis (HD). Patients on CAPD (n = 37) and on haemodialysis (n = 27) were selected on the basis of clinical stability and absence of factors that may interfere with iron metabolism. Parameters measured included routine haematological and biochemical profile; serum iron metabolism (serum iron, transferrin saturation capacity, transferrin saturation index, serum ferritin); erythrocyte ferritin; bone marrow erythroid components and semiqualitative analysis of iron deposits in the bone marrow. The CAPD patients showed higher levels of haemoglobin and transferrin saturation capacity as well as lower serum ferritin than patients on haemodialysis. In the bone marrow, CAPD patients had a higher percentage of red blood cells and in those with low iron‐containing macrophages a higher percentage of sideroblasts than the haemodialysis group. Erythrocyte ferritin levels were similar in both groups. These data suggest more efficient iron metabolism in CAPD patients than in patients on haemodialysis.

Erythroid Phosphatidyl Serine Exposure Is Not Predictive of Thrombotic Risk in Mice with Hemolytic Anemia

ABSTRACTThrombosis is a major complication of human hemolytic anemias such as sickle cell disease, thalassemia, and severe hereditary spherocytosis (HS). Mice with severe HS and severe hereditary elliptocytosis (HE) also suffer from thrombosis, with incidences ranging from 15 and 22% in β-spectrin- and ankyrin-deficient mice, respectively, to 85 to 100% in α-spectrin-deficient and band 3 knockout mice. A contributing factor to thrombosis could be loss of phospholipid asymmetry of the mutant red blood cells (RBCs), with concomitant exposure of the aminophospholipid phosphatidylserine (PS). Increased PS exposure occurs in RBCs from sickle cell and thalassemia patients and in RBCs from band 3-deficient mice. To determine if increased PS exposure correlates with thrombotic risk in HS and HE mice with ankyrin, β-spectrin, and α-spectrin deficiencies, measurements of FITC-labeled annexin V binding to externalized PS on RBCs were performed. PS exposure is elevated in all mice with HS and HE, but the percentage of RBCs with exposed PS does not correlate with thrombotic risk in these mice.