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Blood from twelve volunteers serving on a submarine and breathing elevated levels of CO2 was analyzed for electrolyte, pH, and pCO2 levels in the plasma and in red-cell hemolysates. The method for measuring pH and pCO2 in frozen samples entails certain difficulties due to loss of CO2 during storage. Empirically determined correction factors were used for pH and pCO2. After seven days of exposure to the submarine atmosphere (0.9% CO2) red cell pH was statistically significantly lower, than control values, while plasma pH showed only a tendency to decrease, plasma chloride was decreased and red cell chloride increased. These findings were considered as evidence suggesting existence of a mild respiratory acidosis. After forty-two days of exposure plasma chloride was still significantly reduced and red cell chloride slightly elevated. Moreover, red cell sodium was increased and red cell potassium decreased, while pH values of plasma and red cells did not differ significantly from control levels. The electrolyte shifts observed after forty-two days have been interpreted as evidence suggestive of an existing acidosis.

In the present study, the blood volume of the guinea pig was assessed by direct measures of Hct and dilution samples of autologous red blood cells labeled with sodium chromate. In addition, experimental measures were performed following the administration of the sympathomimetic catecholamine epinephrine to assess the potential influence of splenic mobilization of red cells upon the circulating mass. Doses were selected to elicit maximum contraction of the splenic smooth muscle and discharge of red blood cells. Isoproterenol was administered in identical doses to a separate set of subjects to assess the pharmacological effects of this potent cardiovascular stimulant upon the circulating blood volume. Mean arterial pressure (MAP) and heart rate (HR) were monitored to assess the hemodynamic responses of the system to these agonists. Likewise, measures were performed upon splenectomized individuals for comparison of the systemic effects of the catecholamines.

Background: Unit for Blood Donors, The Indonesian Red Cross Society of Medan City has  established a two-day maximum storage period for PRC that has been processed from Whole  Blood (WB). The quality of the blood is affected by how long the PCR is stored. Objective: To  analyze the effect of Packed Red Cell (PRC) storage time on changes in routine blood values.  Method: This type of research is a quantitative analytical study with comparative numerical  more than two groups to analyze the storage time of PRC blood on changes in routine blood  values. Result: 40 study participants participated in the investigation. Leukocytes, hemoglobin,  and haematocrit were the measured parameters. The value of the erythrocyte decreases with  storage time. The value of the erythrocytes was lower when compared to the storage of  erythrocytes on day 11 than it was on day 1 of storage. When the haemoglobin examination  findings have a p-value of less than 0.05, this means that the haemoglobin against PRC storage  on day 1 and day 1 differ significantly. If the storage time is prolonged, the haemoglobin value  will rise. P-value 0.05 for the findings of the analysis of haematocrit levels shows a significant  difference between PRC storage on days 1 through day 11 and haematocrit, with the  haematocrit value rising as storage duration increases. Conclusion: Haemoglobin and  haematocrit levels, there was a significant increase in changes and erythrocytes during the  eleven-day storage process, a significant decrease but still within normal limits.

An exploration of the ephemera of pop culture from cylinder recordings of the 1800s to the strangest experimental fringes of the avant garde.

Buck sits down with Middle East affairs analyst Hussein Ibish to discuss potential conflict scenarios in the region's near future.

This article is from Revista Brasileira de Hematologia e Hemoterapia , volume 34 . Abstract Objective: To analyze the impact of moderate physical exercise on the total and differential leukocyte counts and red blood cell count of 36 sixty-day-old adult male Wistar rats subjected to early malnourishment. Methods: The rats were divided in nourished (N - casein 17%) and malnourished groups (M - casein 8%) and thesegroups were then subdivided in trained (T) untrained (U) creating four groups NT, NU, MT and MU. The NT and MTgroups were submitted to moderate physical exercise using a treadmill (60 min/day, 5 days/week for 8 weeks). Onthe 1st day, before the training started T0 and 24 hours after the last training day of the week (T1 until T8), a 1 mLaliquot of blood was collected from the animals' tails for analysis. The total leukocyte count was evaluated in a cellcounter with an electronic microscope. The cyanmethemoglobin technique was used to measure the hemoglobin level. The hematocrit values were determined as a percentage using the micro-hematocrit technique with a microcapillaryreader and a cell counter was used to determine the red blood cell count. The t-test was used for statistical analysis and a p-value < 0.05 was considered significant. Data are expressed as means ± standard deviation. Results: There was a significant difference in the total leukocyte count between the NT (9.1 ± 0.1) and MT groups (8.0 ± 0.1) from T1 and in neutrophils between the NT (22.1 ± 0.6) and MT groups (24.6 ± 1.8) from T7 (p < 0.05). There was no statistical significance in the hemoglobin, hematocrit and red blood cell count from T1. Conclusions: According to the results of this study, moderate physical exercise seems to have induced physiologic adaptation in adult rats from T1.

This article is from Revista Brasileira de Hematologia e Hemoterapia , volume 34 . Abstract Objective: To analyze the impact of moderate physical exercise on the total and differential leukocyte counts and red blood cell count of 36 sixty-day-old adult male Wistar rats subjected to early malnourishment. Methods: The rats were divided in nourished (N - casein 17%) and malnourished groups (M - casein 8%) and thesegroups were then subdivided in trained (T) untrained (U) creating four groups NT, NU, MT and MU. The NT and MTgroups were submitted to moderate physical exercise using a treadmill (60 min/day, 5 days/week for 8 weeks). Onthe 1st day, before the training started T0 and 24 hours after the last training day of the week (T1 until T8), a 1 mLaliquot of blood was collected from the animals' tails for analysis. The total leukocyte count was evaluated in a cellcounter with an electronic microscope. The cyanmethemoglobin technique was used to measure the hemoglobin level. The hematocrit values were determined as a percentage using the micro-hematocrit technique with a microcapillaryreader and a cell counter was used to determine the red blood cell count. The t-test was used for statistical analysis and a p-value < 0.05 was considered significant. Data are expressed as means ± standard deviation. Results: There was a significant difference in the total leukocyte count between the NT (9.1 ± 0.1) and MT groups (8.0 ± 0.1) from T1 and in neutrophils between the NT (22.1 ± 0.6) and MT groups (24.6 ± 1.8) from T7 (p < 0.05). There was no statistical significance in the hemoglobin, hematocrit and red blood cell count from T1. Conclusions: According to the results of this study, moderate physical exercise seems to have induced physiologic adaptation in adult rats from T1.

This article is from Revista Brasileira de Hematologia e Hemoterapia , volume 34 . Abstract Objective: To analyze the impact of moderate physical exercise on the total and differential leukocyte counts and red blood cell count of 36 sixty-day-old adult male Wistar rats subjected to early malnourishment. Methods: The rats were divided in nourished (N - casein 17%) and malnourished groups (M - casein 8%) and thesegroups were then subdivided in trained (T) untrained (U) creating four groups NT, NU, MT and MU. The NT and MTgroups were submitted to moderate physical exercise using a treadmill (60 min/day, 5 days/week for 8 weeks). Onthe 1st day, before the training started T0 and 24 hours after the last training day of the week (T1 until T8), a 1 mLaliquot of blood was collected from the animals' tails for analysis. The total leukocyte count was evaluated in a cellcounter with an electronic microscope. The cyanmethemoglobin technique was used to measure the hemoglobin level. The hematocrit values were determined as a percentage using the micro-hematocrit technique with a microcapillaryreader and a cell counter was used to determine the red blood cell count. The t-test was used for statistical analysis and a p-value < 0.05 was considered significant. Data are expressed as means ± standard deviation. Results: There was a significant difference in the total leukocyte count between the NT (9.1 ± 0.1) and MT groups (8.0 ± 0.1) from T1 and in neutrophils between the NT (22.1 ± 0.6) and MT groups (24.6 ± 1.8) from T7 (p < 0.05). There was no statistical significance in the hemoglobin, hematocrit and red blood cell count from T1. Conclusions: According to the results of this study, moderate physical exercise seems to have induced physiologic adaptation in adult rats from T1.

This article is from World Journal of Emergency Surgery : WJES , volume 8 . Abstract Purpose: The aim of this study was to seek whether red cell distribution width (RDW) has a role in the diagnosis of acute appendicitis. It was also aimed to show the relationship of RDW with leukocyte count and C-reactive protein (CRP) level. Methods: This study was conducted via retrospective assessment of the hospital records of the adult patients who were operated for acute appendicitis between January 2010 and February 2013 and had a pathology report that confirmed the diagnosis of acute appendicitis. The patients in the control group were selected from healthy adults of similar age who applied to check-up clinic. Age, gender, leukocyte count, CRP, and RDW values were recorded. This study is a case controlled retrospective clinical study. Results: A total of 590 patients in the acute appendicitis group and 121 patients in the control group were included, making up a total of 711 subjects. The mean RDW levels were 15.4 ± 1.5% in the acute appendicitis group, while 15.9 ± 1.4% in the control group. CRP, leukocyte count were significantly higher in the acute appendicitis group, and RDW level were significantly lower in the acute appendicitis group (p 

This article is from World Journal of Emergency Surgery : WJES , volume 8 . Abstract Purpose: The aim of this study was to seek whether red cell distribution width (RDW) has a role in the diagnosis of acute appendicitis. It was also aimed to show the relationship of RDW with leukocyte count and C-reactive protein (CRP) level. Methods: This study was conducted via retrospective assessment of the hospital records of the adult patients who were operated for acute appendicitis between January 2010 and February 2013 and had a pathology report that confirmed the diagnosis of acute appendicitis. The patients in the control group were selected from healthy adults of similar age who applied to check-up clinic. Age, gender, leukocyte count, CRP, and RDW values were recorded. This study is a case controlled retrospective clinical study. Results: A total of 590 patients in the acute appendicitis group and 121 patients in the control group were included, making up a total of 711 subjects. The mean RDW levels were 15.4 ± 1.5% in the acute appendicitis group, while 15.9 ± 1.4% in the control group. CRP, leukocyte count were significantly higher in the acute appendicitis group, and RDW level were significantly lower in the acute appendicitis group (p 

This article is from World Journal of Emergency Surgery : WJES , volume 8 . Abstract Purpose: The aim of this study was to seek whether red cell distribution width (RDW) has a role in the diagnosis of acute appendicitis. It was also aimed to show the relationship of RDW with leukocyte count and C-reactive protein (CRP) level. Methods: This study was conducted via retrospective assessment of the hospital records of the adult patients who were operated for acute appendicitis between January 2010 and February 2013 and had a pathology report that confirmed the diagnosis of acute appendicitis. The patients in the control group were selected from healthy adults of similar age who applied to check-up clinic. Age, gender, leukocyte count, CRP, and RDW values were recorded. This study is a case controlled retrospective clinical study. Results: A total of 590 patients in the acute appendicitis group and 121 patients in the control group were included, making up a total of 711 subjects. The mean RDW levels were 15.4 ± 1.5% in the acute appendicitis group, while 15.9 ± 1.4% in the control group. CRP, leukocyte count were significantly higher in the acute appendicitis group, and RDW level were significantly lower in the acute appendicitis group (p 

This article is from Turkish Journal of Hematology , volume 31 . Abstract Objective: Obesity and iron deficiency (ID) are the 2 most common nutritional disorders worldwide causing significant public health implications. Obesity is characterized by the presence of low-grade inflammation, which may lead to a number of diseases including insulin resistance (IR) and type 2 diabetes. Increased levels of acute-phase proteins such as C-reactive protein (CRP) have been reported in obesity-related inflammation. The aim of this study was to investigate the impact of obesity/IR on iron and red blood cell related parameters. Materials and Methods: A total of 206 patients and 45 control subjects of normal weight were included in this cross-sectional study. Venous blood samples were taken from each patient to measure hemoglobin (Hb), serum iron (Fe), iron-binding capacity (IBC), ferritin, CRP, fasting blood glucose, and fasting insulin. Body mass index (BMI) and waist-to-hip ratio (WHR) were calculated for each patient. IR was determined using the HOMA-IR formula.Results: Subjects were divided into 3 groups according to BMI. There were 152 severely obese (BMI: 42.6±10.1), 54 mildly obese (BMI: 32.4±2.1), and 45 normal-weight (BMI: 24.3±1.3) patients. Hb levels in severely obese patients and normal controls were 12.8±1.3 g/dL and 13.6±1.8 g/dL, respectively. We found decreasing Fe levels with increasing weight (14.9±6.9 µmol/L, 13.6±6.3 µmol/L, and 10.9±4.6 µmol/L for normal controls and mildly and severely obese patients, respectively). Hb levels were slightly lower in patients with higher HOMA-IR values (13.1±1.5 g/dL vs. 13.2±1.2 g/dL; p=0.36). Serum iron levels were significantly higher in the group with low HOMA-IR values (13.6±5.9 µmol/L vs. 11.6±4.9 µmol/L; p=0.008). IBC was found to be similar in both groups (60.2±11.4 µmol/L vs. 61.9±10.7 µmol/L; p=0.23). Ferritin was slightly higher in patients with higher HOMA-IR values (156.1±209.5 pmol/L vs. 145.3±131.5 pmol/L; p=0.62). Conclusion: Elevated BMI and IR are associated with lower Fe and hemoglobin levels. These findings may be explained by the chronic inflammation of obesity and may contribute to obesity-related co-morbidities. People with IR may present with ID without anemia.

This article is from Systematic Reviews , volume 3 . Abstract Background: Adverse transfusion reactions in the neonatal population are poorly understood and defined. The incidence and pattern of adverse effects due to red blood cell (RBC) transfusion are not well known, and there has been no systematic review of published adverse events. RBC transfusions continue to be linked to the development of morbidities unique to neonates, including chronic lung disease, retinopathy of prematurity, intraventricular haemorrhage and necrotising enterocolitis. Uncertainties about the exact nature of risks alongside benefits of RBC transfusion may contribute to evidence of widespread variation in neonatal RBC transfusion practice.Our review aims to describe clinical adverse effects attributed to small-volume (10–20 mL/kg) RBC transfusions and, where possible, their incidence rates in the neonatal population through the systematic identification of all relevant studies. Methods: A comprehensive search of the following bibliographic databases will be performed: MEDLINE (PubMed/OVID which includes the Cochrane Library) and EMBASE (OVID). The intervention of interest is small-volume (10–20 mL/kg) RBC transfusions in the neonatal population.We will undertake a narrative synthesis of the evidence. If clinical similarity and data quantity and quality permit, we will also carry out meta-analyses on the listed outcomes. Discussion: This systematic review will identify and synthesise the reported adverse effects and associations of RBC transfusions in the neonatal population. We believe that this systematic review is timely and will make a valuable contribution to highlight an existing research gap. Trial Registration: PROSPERO, CRD42013005107http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD4201300 5107

The purpose of the project was to try to determine if variation in host red cell metabolism could influence malaria severity, and whether information obtained could be used in developing new treatments. During the tenure of this contract, a number of studies of the interaction of malaria and red cell metabolism were carried out. This included in vitro interactions in a cultivation system, discussed in Section A, the relationship of the red cell ATP levels of ethnic groups to natural selection by malaria, (Section B), the relationship of the severity of malaria in rhesus monkeys to their red cell ATP levels (Section D), and the pronounced decrease in red cell ATP levels that occurs under some conditions in rodent malaries (Section D). A related study to this general theme was the development of a treatment of malaria involving hyperoxia which was effective in suppressing P vinckei in rats, but not P. berghei.

The effect of oxygen toxicity on red cell aging was experimentally studied. The alterations in age distribution of red cells of rabbits submitted to a high oxygen concentration was determined by density distribution, osmotic fragility, acid fragility, and electron microscopy. Increased osmotic fragility and density of the red blood cells as well as an increased resistance to acid fragility is indicative of an increased population of structurally old cells. Red cell membranes as seen in the electron microscope present morphological features in agreement with this interpretation.

Recently the Naval Blood Research Laboratory has been freezing red blood cells in a collection system which uses either a triple or a quadruple bag setup. Blood collection and red blood cell biochemical modification and freeze-preservation can be accomplished with this system. For the past 6 years the laboratory has been biochemically modifying liquid-stored red blood cells to increase their 2,3 DPG and ATP levels and thus improve the oxygen transport function of the preserved red blood cells upon infusion. Biochemically modified red blood cells, or 'rejuvenated' red blood cells as they are sometimes referred to, can be freeze-preserved or not as the situation demands. Red blood cells that have exceeded their mandatory shelf-life have been biochemically modified with a solution of pyruvate, inosine, glucose, phosphate, and adenine. The stored red blood cells are incubated with the 'rejuvenation' solution for 1 hour at 37 C. Biochemically modified red blood cells must be washed before transfusion whether or not they have been frozen to remove the additives used in the solution. This report describes a new blood collection system. The cost of processing can be reduced at least 50% the storage capacity in the -80 C mechanical refrigerator can be doubled, and the potential for contamination of the blood product is reduced. Biochemically modified freeze-preserved red blood cells have been used successfully in a number of important clinical situations.

Since different types of abnormal red blood cells arise by different etiologic processes, disease diagnosis can often be made by interpretation of red blood cell pathology in conjunction with hematological data and other clinical and laboratory information. 

Since different types of abnormal red blood cells arise by different etiologic processes, disease diagnosis can often be made by interpretation of red blood cell pathology in conjunction with hematological data and other clinical and laboratory information. 

The development of blood storage systems allowed donation and transfusion to be separated in time and space. This separation has permitted the regionalization of donor services with subsequent economies of scale and improvements in the quality and availability of blood products. However, the availability of storage raises the question of how long blood products can and should be stored and how long they are safe and effective. During blood bank cold storage, red cells progressively lose deformability and elasticity due to irreversible changes in the cell membrane. Aim: The aim of this study is to assess the relative importance of these diverse biochemical changes in the stored RBC. Methodology: The donors of the blood units included in this study were healthy by all parameters considered for blood banking. Whole blood of 450ml collection bag unit containing 63ml CPD/SAGM (which has a permissible life span of 42 days) and containing 63 ml of CPDA (which has a life span of 35 days) were subjected to standard component separation. A total of 35 consecutively separated blood bags with 7 segments each were studied. Each segment from the Packed Red Cell unit was removed on days 0, 7, 14, 21, 28, 35 and 42 of PRBC storage, were investigated. The biochemical and hematological parameters such as pH, Lactate, Sr.Potassium, Plasma Haemoglobin, Heamoglobin and Heamatocrit were analyzed in fully automated analyzer. Results and Analysis: RBC unit characteristics just before storage on Day 0 pH (37°C) 7.03+_0.94 (7.20-6.79) Hb (mg/dL) 15.3 +_2.2 (17.9-13.9),Plasma Hemoglobin 3.1+-1.2 gm/dl Lactate (mmol/L) 2 +_ 1.4 (1.3-3.1)Potassium(K) (mmol/L)1.7+-1.2. Extracellular K and Lactate showed a constant increase as the bags aged. Hemoglobin and Haematocrit levels did not change appreciably throughout the storage period. Conclusion: The older RBC may have adverse effects like increase in potassium, lactate but the transfusion department can help the clinician by knowing the patient’s clinical status as well as the age, critical variables like Sepsis by issuing the recent dated Blood units. 

The development of blood storage systems allowed donation and transfusion to be separated in time and space. This separation has permitted the regionalization of donor services with subsequent economies of scale and improvements in the quality and availability of blood products. However, the availability of storage raises the question of how long blood products can and should be stored and how long they are safe and effective. During blood bank cold storage, red cells progressively lose deformability and elasticity due to irreversible changes in the cell membrane. Aim: The aim of this study is to assess the relative importance of these diverse biochemical changes in the stored RBC. Methodology: The donors of the blood units included in this study were healthy by all parameters considered for blood banking. Whole blood of 450ml collection bag unit containing 63ml CPD/SAGM (which has a permissible life span of 42 days) and containing 63 ml of CPDA (which has a life span of 35 days) were subjected to standard component separation. A total of 35 consecutively separated blood bags with 7 segments each were studied. Each segment from the Packed Red Cell unit was removed on days 0, 7, 14, 21, 28, 35 and 42 of PRBC storage, were investigated. The biochemical and hematological parameters such as pH, Lactate, Sr.Potassium, Plasma Haemoglobin, Heamoglobin and Heamatocrit were analyzed in fully automated analyzer. Results and Analysis: RBC unit characteristics just before storage on Day 0 pH (37°C) 7.03+_0.94 (7.20-6.79) Hb (mg/dL) 15.3 +_2.2 (17.9-13.9),Plasma Hemoglobin 3.1+-1.2 gm/dl Lactate (mmol/L) 2 +_ 1.4 (1.3-3.1)Potassium(K) (mmol/L)1.7+-1.2. Extracellular K and Lactate showed a constant increase as the bags aged. Hemoglobin and Haematocrit levels did not change appreciably throughout the storage period. Conclusion: The older RBC may have adverse effects like increase in potassium, lactate but the transfusion department can help the clinician by knowing the patient’s clinical status as well as the age, critical variables like Sepsis by issuing the recent dated Blood units. 

This article is from Biomedical Optics Express , volume 3 . Abstract The feasibility of detecting red blood cell (RBC) aggregation with photoacoustics (PAs) was investigated theoretically and experimentally using human and porcine RBCs. The theoretical PA signals and spectra generated from such samples were examined for several hematocrit levels and aggregates sizes. The effect of a finite transducer bandwidth on the received PA signal was also examined. The simulation results suggest that the dominant frequency of the PA signals from non-aggregated RBCs decreases towards clinical frequency ranges as the aggregate size increases. The experimentally measured mean spectral power increased by ~6 dB for the largest aggregate compared to the non-aggregated samples. Such results confirm the theoretical predictions and illustrate the potential of using PA imaging for detecting RBC aggregation.

This article is from Biomedical Optics Express , volume 3 . Abstract The feasibility of detecting red blood cell (RBC) aggregation with photoacoustics (PAs) was investigated theoretically and experimentally using human and porcine RBCs. The theoretical PA signals and spectra generated from such samples were examined for several hematocrit levels and aggregates sizes. The effect of a finite transducer bandwidth on the received PA signal was also examined. The simulation results suggest that the dominant frequency of the PA signals from non-aggregated RBCs decreases towards clinical frequency ranges as the aggregate size increases. The experimentally measured mean spectral power increased by ~6 dB for the largest aggregate compared to the non-aggregated samples. Such results confirm the theoretical predictions and illustrate the potential of using PA imaging for detecting RBC aggregation.

This article is from Biomedical Optics Express , volume 3 . Abstract The feasibility of detecting red blood cell (RBC) aggregation with photoacoustics (PAs) was investigated theoretically and experimentally using human and porcine RBCs. The theoretical PA signals and spectra generated from such samples were examined for several hematocrit levels and aggregates sizes. The effect of a finite transducer bandwidth on the received PA signal was also examined. The simulation results suggest that the dominant frequency of the PA signals from non-aggregated RBCs decreases towards clinical frequency ranges as the aggregate size increases. The experimentally measured mean spectral power increased by ~6 dB for the largest aggregate compared to the non-aggregated samples. Such results confirm the theoretical predictions and illustrate the potential of using PA imaging for detecting RBC aggregation.

Aim: It has been reported that red cell distribution width (RDW) and hypertension are somehow related, but there is no well-established evidence about the probable relationship between RDW and preeclampsia. The present study aimed to determine whether RDW in the first trimester can be used to predict the presence and severity of preeclampsia.  Material and Method: This is a retrospective review of 57 healthy pregnant women, 42 women with mild preeclampsia, and 18 women with severe preeclampsia who delivered at the study center. These three groups were compared with respect to complete blood count parame-ters obtained during the first trimester.  Results: When compared with the control group, systolic blood pressure, diastolic blood pressure, leukocyte count, RDW, blood urea nitrogen, and proteinuria were significantly higher in the severe preeclampsia group (respectively p&lt;0.001, p&lt;0.001, p=0.036, p&lt;0.001, p&lt;0.001, and p&lt;0.001). The median RDW values of control, mild, and severe preeclampsia groups were 12.51% (range: 10.6-15.02%), 13.2% (range: 10.45-15.5%), and 13.7% (range: 11.9%-14.7%). RDW was significantly higher in the severe preeclampsia group than in the control group (p&lt;0.001) and mild preeclampsia group (p=0.001). However, mild preeclampsia and control groups had statistically similar RDW values (p&gt;0.05).  Discussion: Increased RDW in the first trimester can be utilized to predict severe preeclampsia, but RDW values do not seem to correlate with the severity of preeclampsia.

This article is from DNA Research: An International Journal for Rapid Publication of Reports on Genes and Genomes , volume 19 . Abstract The mitochondria and chloroplasts in plant cells are originated from bacterial endosymbioses, and they still replicate their own genome and divide in a similar manner as their ancestors did. It is thus likely that the organelle transcription is coordinated with its proliferation cycle. However, this possibility has not extensively been explored to date, because in most plant cells there are many mitochondria and chloroplasts that proliferate asynchronously. It is generally believed that the gene transfer from the organellar to nuclear genome has enabled nuclear control of the organelle functions during the evolution of eukaryotic plant cells. Nevertheless, no significant relationship has been reported between the organelle transcriptome and the host cell cycle even in Chlamydomonas reinhardtii. While the organelle proliferation cycle is not coordinated with the cell cycle in vascular plants, in the unicellular red alga Cyanidioschyzon merolae that contains only one mitochondrion, one chloroplast, and one nucleus per cell, each of the organelles is known to proliferate at a specific phase of the cell cycle. Here, we show that the expression of most of the organelle genes is highly coordinated with the cell cycle phases as well as with light regimes in clustering analyses. In addition, a strong correlation was observed between the gene expression profiles in the mitochondrion and chloroplast, resulting in the identification of a network of functionally related genes that are co-expressed during organelle proliferation.

The analysis of non-equilibrium steady states of biochemical reaction networks relies on finding the configurations of fluxes and chemical potentials satisfying stoichiometric (mass balance) and thermodynamic (energy balance) constraints. Efficient methods to explore such states are crucial to predict reaction directionality, calculate physiologic ranges of variability, estimate correlations, and reconstruct the overall energy balance of the network from the underlying molecular processes. While different techniques for sampling the space generated by mass balance constraints are currently available, thermodynamics is generically harder to incorporate. Here we introduce a method to sample the free energy landscape of a reaction network at steady state. In its most general form, it allows to calculate distributions of fluxes and concentrations starting from trial functions that may contain prior biochemical information. We apply our method to the human red blood cell's metabolic network, whose space of mass-balanced flux states has been sampled extensively in recent years. Specifically, we profile its thermodynamically feasible flux configurations, characterizing in detail how fluctuations of fluxes and potentials are correlated. Based on this, we derive the cell's energy balance in terms of entropy production, chemical work done and thermodynamic efficiency.

ABSTRACT Aims: The use of hematological parameters in the prognostic assessment of acute coronary syndrome (ACS) has become common in recent years. Thus, our study aimed to evaluate the relationship between hemoglobin to red cell distribution width (RDW) ratio (HRR) and prognosis of these patients. Methods: A retrospective evaluation was conducted on patients who presented to the emergency department between 01.09.2023 and 01.04.2024 and received a diagnosis of ACS. HRR was determined by dividing the hemoglobin concentration by the red cell distribution width (RDW). The patients were categorized into two groups based on their HRR values: high HRR patients and low HRR patients, using a specified HRR cut-off value. Statistical comparisons were conducted on all parameters between the two patient groups. The variables potentially linked to mortality were analyzed using receiver operating characteristic (ROC) analysis. Results: The in-hospital mortality rate, vasopressor needs, and MV support requirements were significantly higher in the low HRR (?0.828) group than in the high HRR (>0.828) group (p

ABSTRACT Aims: The use of hematological parameters in the prognostic assessment of acute coronary syndrome (ACS) has become common in recent years. Thus, our study aimed to evaluate the relationship between hemoglobin to red cell distribution width (RDW) ratio (HRR) and prognosis of these patients. Methods: A retrospective evaluation was conducted on patients who presented to the emergency department between 01.09.2023 and 01.04.2024 and received a diagnosis of ACS. HRR was determined by dividing the hemoglobin concentration by the red cell distribution width (RDW). The patients were categorized into two groups based on their HRR values: high HRR patients and low HRR patients, using a specified HRR cut-off value. Statistical comparisons were conducted on all parameters between the two patient groups. The variables potentially linked to mortality were analyzed using receiver operating characteristic (ROC) analysis. Results: The in-hospital mortality rate, vasopressor needs, and MV support requirements were significantly higher in the low HRR (?0.828) group than in the high HRR (>0.828) group (p

With the administration of prehospital packed red blood cells to trauma patients, subsequent activation of a massive transfusion protocol can lead to additional red cell transfusion prior to plasma products. This may lead prehospital patients to have a low red cell to plasma product transfusion ratio – which is undesirable. This retrospective study seeks to identify whether PRBC to plasma product ratio is lower for those transfused prehospitally in the first 6 and 24 hours of admission compared to patients whose transfusion starts in the emergency department

This article is from Critical Care , volume 16 . Abstract Introduction: Recently, red cell distribution width (RDW), a measure of erythrocyte size variability, has been shown to be a prognostic marker in critical illness. The aim of this study was to investigate whether adding RDW has the potential to improve the prognostic performance of the simplified acute physiology score (SAPS) to predict short- and long-term mortality in an independent, large, and unselected population of intensive care unit (ICU) patients. Methods: This observational cohort study includes 17,922 ICU patients with available RDW measurements from different types of ICUs. We modeled the association between RDW and mortality by using multivariable logistic regression, adjusting for demographic factors, comorbidities, hematocrit, and severity of illness by using the SAPS. Results: ICU-, in-hospital-, and 1-year mortality rates in the 17,922 included patients were 7.6% (95% CI, 7.2 to 8.0), 11.2% (95% CI, 10.8 to 11.7), and 25.4% (95% CI, 24.8 to 26.1). RDW was significantly associated with in-hospital mortality (OR per 1% increase in RDW (95%CI)) (1.14 (1.08 to 1.19), P < 0.0001), ICU mortality (1.10 (1.06 to 1.15), P < 0.0001), and 1-year mortality (1.20 (95% CI, 1.14 to 1.26); P < 0.001). Adding RDW to SAPS significantly improved the AUC from 0.746 to 0.774 (P < 0.001) for in-hospital mortality and 0.793 to 0.805 (P < 0.001) for ICU mortality. Significant improvements in classification of SAPS were confirmed in reclassification analyses. Subgroups demonstrated robust results for gender, age categories, SAPS categories, anemia, hematocrit categories, and renal failure. Conclusions: RDW is a promising independent short- and long-term prognostic marker in ICU patients and significantly improves risk stratification of SAPS. Further research is needed the better to understand the pathophysiology underlying these effects.

This article is from Trials , volume 14 . Abstract Background: Transfusion of red blood cells (RBC) is recommended in septic shock and the majority of these patients receive RBC transfusion in the intensive care unit (ICU). However, benefit and harm of RBCs have not been established in this group of high-risk patients. Methods/Design: The Transfusion Requirements in Septic Shock (TRISS) trial is a multicenter trial with assessor-blinded outcome assessment, randomising 1,000 patients with septic shock in 30 Scandinavian ICUs to receive transfusion with pre-storage leuko-depleted RBC suspended in saline-adenine-glucose and mannitol (SAGM) at haemoglobin level (Hb) of 7 g/dl or 9 g/dl, stratified by the presence of haematological malignancy and centre. The primary outcome measure is 90-day mortality. Secondary outcome measures are organ failure, ischaemic events, severe adverse reactions (SARs: anaphylactic reaction, acute haemolytic reaction and transfusion-related circulatory overload, and acute lung injury) and mortality at 28 days, 6 months and 1 year.The sample size will enable us to detect a 9% absolute difference in 90-day mortality assuming a 45% event rate with a type 1 error rate of 5% and power of 80%. An interim analysis will be performed after 500 patients, and the Data Monitoring and Safety Committee will recommend the trial be stopped if a group difference in 90-day mortality with P ≤0.001 is present at this point. Discussion: The TRISS trial may bridge the gap between clinical practice and the lack of efficacy and safety data on RBC transfusion in septic shock patients. The effect of restrictive versus liberal RBC transfusion strategy on mortality, organ failure, ischaemic events and SARs will be evaluated. Trial registration: ClinicalTrials.gov: NCT01485315. Registration date 30 November 2011. First patient was randomised 3 December 2011.

This article is from Annals of Laboratory Medicine , volume 33 . Abstract Background: This study aimed at assessing the number of red blood cell (RBC) units transfused at different types of medical institution and examining the characteristics of transfusion recipients. Methods: We calculated and compared the number of transfusion recipients, total RBC units transfused, and RBC units transfused per recipient. Study data were extracted from insurance benefits reimbursement claims for RBC units at the Health Insurance Review & Assessment Service from 2006 to 2010. Results: Between 2006 and 2010, the number of recipients of RBC units increased from 298,049 to 376,445, the number of RBC units transfused increased from 1,460,799 to 1,841,695, and the number of RBC units transfused per recipient changed from 4.90 to 4.89. The number of recipients aged ≥65 yr increased from 133,833 (44.9%) in 2006 to 196,127 (52.1%) in 2010. The highest number of RBC units was transfused to patients with neoplastic diseases (31.9%) and diseases of the musculoskeletal system and connective tissue (14.4%). More than 80% of the total number of RBC units were transfused at tertiary and general hospitals. However, this composition rate was slightly decreasing, with the composition rate for hospitals increasing from 12.6% to 16.3%. Conclusions: This study revealed an increase in the number of RBC units transfused over a 5-yr period due to an increase in the number of transfused recipients, especially recipients aged ≥65 yr; moreover, the number of RBC units transfused differed based on medical institution type. These results provide fundamental data on RBC transfusions required for future research.

This article is from Annals of Laboratory Medicine , volume 33 . Abstract Background: This study aimed at assessing the number of red blood cell (RBC) units transfused at different types of medical institution and examining the characteristics of transfusion recipients. Methods: We calculated and compared the number of transfusion recipients, total RBC units transfused, and RBC units transfused per recipient. Study data were extracted from insurance benefits reimbursement claims for RBC units at the Health Insurance Review & Assessment Service from 2006 to 2010. Results: Between 2006 and 2010, the number of recipients of RBC units increased from 298,049 to 376,445, the number of RBC units transfused increased from 1,460,799 to 1,841,695, and the number of RBC units transfused per recipient changed from 4.90 to 4.89. The number of recipients aged ≥65 yr increased from 133,833 (44.9%) in 2006 to 196,127 (52.1%) in 2010. The highest number of RBC units was transfused to patients with neoplastic diseases (31.9%) and diseases of the musculoskeletal system and connective tissue (14.4%). More than 80% of the total number of RBC units were transfused at tertiary and general hospitals. However, this composition rate was slightly decreasing, with the composition rate for hospitals increasing from 12.6% to 16.3%. Conclusions: This study revealed an increase in the number of RBC units transfused over a 5-yr period due to an increase in the number of transfused recipients, especially recipients aged ≥65 yr; moreover, the number of RBC units transfused differed based on medical institution type. These results provide fundamental data on RBC transfusions required for future research.

This article is from Annals of Laboratory Medicine , volume 33 . Abstract Background: This study aimed at assessing the number of red blood cell (RBC) units transfused at different types of medical institution and examining the characteristics of transfusion recipients. Methods: We calculated and compared the number of transfusion recipients, total RBC units transfused, and RBC units transfused per recipient. Study data were extracted from insurance benefits reimbursement claims for RBC units at the Health Insurance Review & Assessment Service from 2006 to 2010. Results: Between 2006 and 2010, the number of recipients of RBC units increased from 298,049 to 376,445, the number of RBC units transfused increased from 1,460,799 to 1,841,695, and the number of RBC units transfused per recipient changed from 4.90 to 4.89. The number of recipients aged ≥65 yr increased from 133,833 (44.9%) in 2006 to 196,127 (52.1%) in 2010. The highest number of RBC units was transfused to patients with neoplastic diseases (31.9%) and diseases of the musculoskeletal system and connective tissue (14.4%). More than 80% of the total number of RBC units were transfused at tertiary and general hospitals. However, this composition rate was slightly decreasing, with the composition rate for hospitals increasing from 12.6% to 16.3%. Conclusions: This study revealed an increase in the number of RBC units transfused over a 5-yr period due to an increase in the number of transfused recipients, especially recipients aged ≥65 yr; moreover, the number of RBC units transfused differed based on medical institution type. These results provide fundamental data on RBC transfusions required for future research.

Since 1983 when it became apparent that the human immunodeficiency virus (HIV) could be transmitted through blood transfusions, the number of blood transfusions administered in the United States has decreased significantly (1-7). A restrictive transfusion practice is now being employed, even though much of the reported data in support of this practice are from retrospective studies and thus incomplete (8-21). This paper will report how anemia affects oxygen delivery, hemostasis and non-surgical blood loss, and nitric oxide production and platelet dysfunction. We will discuss normovolemic and hypovolemic anemia, as well as central blood volume and peripheral blood volume, and will report how red blood cell transfusions may affect morbidity and mortality.

Post-Cold War operational planning occurs in a multi-polar environment that lacks a true peer competitor. The diverse nature of current military threats is compounded by the threat of asymmetric warfare designed to exploit critical U.S. military vulnerabilities. The publication of Unrestricted Warfare by two People's Liberation Army colonels in China is suggestive of the nature of future adversaries. It is this author's contention that current operational planning is not suited to: (1) planning operations against a future, asymmetric adversary; and (2) countering the operations of said adversary. This author will propose the establishment of a standing Red Cell on each theater CINC staff. This paper will provide an overview of projected asymmetric threats, the functional nature of the Red Cell. It will detail the benefits such an organization would offer the theater CINC to better exploit an enemy's critical vulnerabilities to achieve the enemy's culmination while deflecting an enemy's efforts at friendly culmination.

Red cell electrophoretic mobilities have been determined on cells from 6 baboons subjected to hemorrhagic shock and 2 baboons in E. coli shock. Studies of cells suspended both in saline and in their own plasma showed electrophoretic mobility in hemorrhagic shock to be unchanged from control values. Power function analysis showed the maximum undetectable change for cells measured in saline would be 6.7%, and in plasma 12.2%. Use of either heparin or EDTA as anticoagulant, or absence of anticoagulant, did not affect the mobilities of either control or shock cells. It is concluded that loss of red cell electronegativity is not an important factor in producing red cell aggregation in hemorrhagic shock, but that this may be of significance in the septic shock.

Red cell electrophoretic mobilities have been determined on cells from 6 baboons subjected to hemorrhagic shock and 2 baboons in E. coli shock. Studies of cells suspended both in saline and in their own plasma showed electrophoretic mobility in hemorrhagic shock to be unchanged from control values. Power function analysis showed the maximum undetectable change for cells measured in saline would be 6.7%, and in plasma 12.2%. Use of either heparin or EDTA as anticoagulant, or absence of anticoagulant, did not affect the mobilities of either control or shock cells. It is concluded that loss of red cell electronegativity is not an important factor in producing red cell aggregation in hemorrhagic shock, but that this may be of significance in the septic shock.

This article is from BMJ Open , volume 3 . Abstract Context: Reports evaluating a possible association between necrotising enterocolitis (NEC) and blood transfusion have been predominantly case–control studies. As the possible associations of disease with any variable on which cases and controls have been matched cannot be explored, a cohort study would offer a solution to this problem. Objective: Our objective was to evaluate the association between exposure to a packed red blood cell (PRBC) transfusion and development of NEC in a cohort where biases of matching are omitted. Design: In a retrospective cohort, exposed infants were defined as those who received a transfusion and did not develop NEC or developed NEC within 48 h of the transfusion. All others were considered unexposed. Setting: A single regional perinatal centre in Memphis, Tennessee, USA. Patients: 3060 ≤1500 g birth weights (BW) were included. Outcome measures: The relative risk of developing NEC after exposure to a PRBC transfusion was measured. Results: 3060 infants were identified. 174 infants (5.7%) developed NEC; 116 of the 174 infants (67%) were exposed. NEC infants had a significantly lower BW (924 vs 1042 g) and required a longer stay on a ventilator (7 vs 2 days). Divided into groups, infants with BW ≤750 , 751–1000 , 1001–1250 g and 1251–1500 g (n=52, 51, 46 and 25, respectively) had a relative risk of 0.14, 0.46, 1.83 and 1.78 (p

This article is from Annals of Intensive Care , volume 1 . Abstract Background: Microcirculation plays a vital role in the development of multiple organ failure in severe sepsis. The effects of red blood cell (RBC) transfusions on these tissue oxygenation and microcirculation variables in early severe sepsis are not well defined. Methods: This is a prospective, observational study of patients with severe sepsis requiring RBC transfusions of one to two units of non-leukoreduced RBCs for a hemoglobin < 7.0, or for a hemoglobin between 7.0 and 9.0 with lactic acidosis or central venous oxygen saturation < 70%. This study took place in a 54-bed, medical-surgical intensive care unit of a university-affiliated hospital. Thenar tissue oxygen saturation was measured by using a tissue spectrometer on 21 patients, and a vaso-occlusive test was performed before and 1 hour after transfusion. The sublingual microcirculation was assessed with a Sidestream Dark Field device concomitantly on 11 of them. Results: RBC transfusion resulted in increase in hemoglobin (7.23 (± 0.87) to 8.75 (± 1.06) g/dl; p < 0.001). RBC transfusion did not globally affect near-infrared spectrometry (NIRS)-derived variables. However, percent change in muscle oxygen consumption was negatively correlated with baseline (r = - 0.679, p = 0.001). There was no statistically significant correlation between percent change in vascular reactivity and baseline (p = 0.275). There was a positive correlation between percent change in oxygen consumption and percent change in vascular reactivity (r = 0.442, p = 0.045). In the 11 patients, RBC transfusion did not globally affect NIRS-derived variables or SDF-derived variables. There was no statistically significant correlation between percent change in small vessel perfusion and baseline perfusion (r = -0.474, p = 0.141), between percent change in small vessel flow and baseline flow (r = -0.418, p = 0.201), or between percent change in small vessel perfusion and percent change in small vessel flow (r = 0.435, p = 0.182). Conclusions: In a small sample population, muscle tissue oxygen consumption, microvascular reactivity and sublingual microcirculation were globally unaltered by RBC transfusion in severe septic patients. However, muscle oxygen consumption improved in patients with low baseline and deteriorated in patients with preserved baseline. Future research with larger samples is needed to further examine the association between RBC transfusion and outcomes of patients resuscitated early in severe sepsis, with an emphasis on elucidating the potential contribution of microvascular factors.

The significance of the transformations in red cell shape observed during the Skylab study must be considered relative to the limitation of man's participation in extended space flight missions. The results of this one study are not conclusive with respect to this question. Based on these examinations of red cells in normal, healthy men and based on other Skylab experiment data relative to the functional capacity of the red cells in vitro and the performance capacity of man as an integrated system, the changes observed would not appear to be the limiting factor in determining man's stay in space. However, the results of this experiment and the documented red cell mass loss during space flight raise serious questions at this time relative to the selection criteria utilized for passengers and crews of future space flights. Until the specific cause and impact of the red cell shape change on cell survival in vivo can be resolved, individuals with diagnosed hematologic abnormalities should not be considered as prime candidates for missions, especially those of longer duration.

This article is from Asian Journal of Transfusion Science , volume 7 . Abstract Context:: Detailed reports of red cell alloantibody frequencies and specificities in the Thai population are limited. The aims of this study were to determine the specificity and compare the frequency of alloantibodies detected using column agglutination technology (CAT) and conventional tube techniques in blood donors and previously transfused patients. Settings and Design:: We retrospectively reviewed antibody screening and identification records for two time periods: January-December 2006 during which conventional tube techniques were used and January 2008-December 2009 when CAT was used. Results:: The overall prevalence of alloantibodies in both patients and donors when using conventional tube techniques was 0.7%, for patients only was 0.9% and donors 0.6%. The most frequent antibodies detected in both groups were anti-Lea, anti-Mia, anti-Leb, anti-P1 and anti-E. When using CAT, alloantibodies were found in 0.8% of patients and 0.13% of donors with the five most common alloantibodies found in patients were anti-Mia, anti-E, anti-Lea, anti-c and anti-Leb respectively. Similarly the common alloantibody specificities in donors were anti-Lea, anti-Mia, anti-Leb, anti-M and anti-D. Conclusions:: One of the most commonly identified alloantibodies in the Thai population studied was anti-Mia suggesting that Mia positive red cells should routinely be included in antibody screening and identification in this population. For antibody screening and identification, CAT method detected immune and warm alloantibody (ies) more frequently than that associated with conventional tube techniques.

This article is from Annals of Intensive Care , volume 1 . Abstract Red blood cell (RBC) transfusion is a common intervention in intensive care unit (ICU) patients. Anemia is frequent in this population and is associated with poor outcomes, especially in patients with ischemic heart disease. Although blood transfusions are generally given to improve tissue oxygenation, they do not systematically increase oxygen consumption and effects on oxygen delivery are not always very impressive. Blood transfusion may be lifesaving in some circumstances, but many studies have reported increased morbidity and mortality in transfused patients. This review focuses on some important aspects of RBC transfusion in the ICU, including physiologic considerations, a brief description of serious infectious and noninfectious hazards of transfusion, and the effects of RBC storage lesions. Emphasis is placed on the importance of personalizing blood transfusion according to physiological endpoints rather than arbitrary thresholds.

The physiologic role of red cell 2,3 DPG has been studied in various situations. Healthy volunteers were studied after exposure to a simulated altitude of 4,500 meters. Hyperventilated, anemic baboons were studied to determine the effects of therapeutic transfusions of red cells with high 2,3 DPG and low affinity for oxygen and of red cells with low 2,3 DPG and high affinity for oxygen. The red cell 2,3 DPG level affects the in vivo P50 value which, in turn, affects erythropoietin production. In the baboon, the red cell 2,3 DPG level has been shown to increase oxygen delivery to tissue and decrease blood flow requirements to maintain oxygen consumption. In hyperventilated, anemic baboons, red cells with decreased 2,3 DPG and increased affinity for oxygen produced a significant increase in cerebral blood flow.

The physiologic role of red cell 2,3 DPG has been studied in various situations. Healthy volunteers were studied after exposure to a simulated altitude of 4,500 meters. Hyperventilated, anemic baboons were studied to determine the effects of therapeutic transfusions of red cells with high 2,3 DPG and low affinity for oxygen and of red cells with low 2,3 DPG and high affinity for oxygen. The red cell 2,3 DPG level affects the in vivo P50 value which, in turn, affects erythropoietin production. In the baboon, the red cell 2,3 DPG level has been shown to increase oxygen delivery to tissue and decrease blood flow requirements to maintain oxygen consumption. In hyperventilated, anemic baboons, red cells with decreased 2,3 DPG and increased affinity for oxygen produced a significant increase in cerebral blood flow.

Cell Membrane The Red Blood Cell as a Model

Recent clinical studies in trauma patients indicate that treatment of anemia by transfusion with previously cryopreserved packed red blood cells is superior to that of aged units stored under standard conditions, but the Food and Drug Administration currently restricts their use to 14 days after thawing. The effect of longer term liquid storage on development of the biochemical, metabolic, and morphologic changes collectively known as the red blood cell storage lesion is unknown. In the present study, we attempted to compare and quantify the development of the red blood cell storage lesion of previously cryopreserved red cell units to conventional blood storage. Our findings indicate that, in addition to significantly altered characteristics post thaw, the common indicators of red blood cell storage lesion developed more rapidly in previously cryopreserved red cells. To achieve a satisfactory safety profile for transfusion of previously cryopreserved red blood cells, these factors must be considered in addition to red cell viability and post-transfusion recovery. This investigation provides insight into the durability of these cells after storage at -80 deg C and may guide potential expansion of red blood cell cryopreservation in civilian, trauma, and military settings. Cryopreservation of red blood cell units at -80 deg C for a prolonged period is a promising adjunct to standard blood banking techniques. The post-thaw characteristics are markedly different than fresh packed red blood cells, and the development of the red blood cell storage lesion is accelerated in the post-thaw period. Post-thaw storage duration may be further studied to provide additional longevity to these red cell products in vitro and in vivo.

Recent clinical studies in trauma patients indicate that treatment of anemia by transfusion with previously cryopreserved packed red blood cells is superior to that of aged units stored under standard conditions, but the Food and Drug Administration currently restricts their use to 14 days after thawing. The effect of longer term liquid storage on development of the biochemical, metabolic, and morphologic changes collectively known as the red blood cell storage lesion is unknown. In the present study, we attempted to compare and quantify the development of the red blood cell storage lesion of previously cryopreserved red cell units to conventional blood storage. Our findings indicate that, in addition to significantly altered characteristics post thaw, the common indicators of red blood cell storage lesion developed more rapidly in previously cryopreserved red cells. To achieve a satisfactory safety profile for transfusion of previously cryopreserved red blood cells, these factors must be considered in addition to red cell viability and post-transfusion recovery. This investigation provides insight into the durability of these cells after storage at -80 deg C and may guide potential expansion of red blood cell cryopreservation in civilian, trauma, and military settings. Cryopreservation of red blood cell units at -80 deg C for a prolonged period is a promising adjunct to standard blood banking techniques. The post-thaw characteristics are markedly different than fresh packed red blood cells, and the development of the red blood cell storage lesion is accelerated in the post-thaw period. Post-thaw storage duration may be further studied to provide additional longevity to these red cell products in vitro and in vivo.

The red cell and plasma volumes of the total rat and of its individual tissues and organs were determined for animals exposed to 5 C for four hours, 24 hours, two weeks, and six weeks. In addition, the tissue hematocrits were determined. These values were compared to those of rats kept at 24 C. - labeled erythrocytes and albumin were given intravenously and allowed to mix; the rats were then frozen in liquid nitrogen. The organs and tissues were removed in the frozen state, assayed for radioactivity, and blood cell and plasma volumes were calculated on a unit weight basis. Changes in blood cell and plasma volumes were observed for the total rat and for many of the individual organs. There was a significant increase in the red cell content of the total rat within 24 hours of cold exposure. After six weeks, the total blood volume was increased by approximately 20% over the control level, and the increase in erythrocyte volume was slightly more than the increase in plasma volume. The hematocrit of heart blood was 44.8 after six weeks exposure as compared to 41.5 for controls. In general, it can be said that the somatic parts of the body showed increases in blood volume whereas the visceral parts had decreased volumes.