Red Blood Cell Deformability and Distribution Width in Patients with Hematologic Neoplasms.

BACKGROUND: Despite increasing evidence that red blood cell (RBC) deformability is impaired in pathologic conditions, little research has been done on RBC deformability in hematologic diseases. The authors measured RBC deformability in patients with various hematologic diseases, including hematologic malignancies. METHODS: A total of 568 patients who underwent bone marrow (BM) examination for initial diagnosis were enrolled. We collected the subjects' age, gender, diagnosis of BM examination, and complete blood count results. The RBC deformability, which was quantified by an elongation index, was measured by a microfluidic ektacytometer. RESULTS: RBC deformability was lower in primary myelofibrosis, acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), chronic myeloid leukemia (CML), and acute lymphoblastic leukemia (ALL) from least to greatest. When the correlation between red blood cell distribution width (RDW) and RBC deformability was analyzed for 370 subjects in hematologic neoplasms, the correlation coefficient of RDW was -0.2974 (p < 0.01). When comparing MDS and aplastic anemia (AA), the deformability of MDS was significantly lower than that of AA. CONCLUSIONS: RBC deformability was decreased in leukemic diseases such as AML, MDS, CML, and ALL compared to control, and RDW showed a negative correlation with deformability. RBC deformability may be used as a complementary differential diagnostic test for MDS and AA.

Severe Acute Respiratory Syndrome Coronavirus-2 Antibody Responses in Hospitalized Patients with Coronavirus Disease 2019 in Daegu, Korea.

BACKGROUND: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) started to spread in Daegu beginning at the end of February 2020. IgG and IgM antibodies against SARS-CoV-2 were measured in hospitalized patients with COVID-19 with moderate to severe symptoms to improve the understanding of antibody responses. METHODS: We enrolled 312 patients with COVID-19 admitted to seven hospitals located in Daegu. Using serum (or plasma) samples from patients with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infections, both IgG and IgM antibodies were measured using commercial enzyme-linked immunosorbent assay (R-FIND CO¬VID-19 ELISA, SG medical, Seoul, Korea). RESULTS: The median value from the initial diagnosis, confirmed by SARS-CoV-2 PCR, to the sampling date was 24 days (day 1 to 88). The total positive rate of IgG was 93.9% and the positive IgM rate was 39.4%, without considering the elapsed period after diagnosis. Positive IgG and IgM rates were highest at 100.0% and 59.0%, respectively, at 3 weeks (15 - 21 days). IgG showed a high positive rate of 79.3% even within 7 days after the initial diag-nosis of the disease and maintained a positive rate of 97.8% until after 8 weeks. CONCLUSIONS: Among hospitalized patients with COVID-19, IgG was detected from the beginning of the diagnosis and persisted for an extended time period.

Prevalence of SARS-CoV-2 Antibody in 2,935 Healthcare Workers at 6 Major Hospitals, Daegu, Korea.

BACKGROUND: In Korea, the first community outbreak of coronavirus disease 2019 (COVID-19) occurred in Daegu on February 18, 2020. This study was performed to investigate the prevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibodies in healthcare workers (HCWs) at 6 major hospitals in Daegu. METHODS: Blood specimens of 2,935 HCWs at 6 major hospitals in Daegu from January 2021 to February 2021 were collected. Every specimen was tested for antibody against SARS-CoV-2 using both Elecsys Anti-SARS-CoV-2 electrochemiluminescence immunoassay (Roche Diagnostics, Rotkreuz, Switzerland) and R-FIND COVID-19 IgG/M/A enzyme-linked immunosorbent assay kit (SG medical Inc., Seoul, Korea) as screening tests. If 1 or more of these screening test results was positive, 2 additional antibody tests were performed using Abbott Anti-SARS-CoV-2 IgG assay (Abbott, Abbott Park, IL, USA) and cPass SARS-CoV-2 Neutralization Antibody Detection Kit (GenScript USA Inc., Piscataway, NJ, USA). If 2 or more of the total 4 test results were positive, it was determined as positive for the antibody against SARS-CoV-2. RESULTS: According to the criteria of SARS-CoV-2 antibody positivity determination, 12 subjects were determined as positive. The overall positive rate of the SARS-CoV-2 antibody was 0.41% (12/2,935). Of the 12 subjects determined as positive, 7 were diagnosed with COVID-19, and the remaining 5 were nondiagnosed cases of COVID-19. CONCLUSION: In early 2021, the overall seroprevalence of SARS-CoV-2 antibody among HCW located in Daegu was 0.41%, and 0.17% excluding COVID-19 confirmed subjects. These results were not particularly high compared with the general public and were much lower than HCWs in other countries.

Erythrocyte Alloimmunity and Genetic Variance: Results from the Collaborative Study of Alloimmunity to Antigen Diversity in Asian Populations (All ADP).

As an East-Asian international study, we evaluated erythrocyte alloimmunity by gender and history of transfusion or pregnancy. In total, data from more than 1,826,000 patients were analyzed, from whom 26,170 irregular erythrocyte antibodies were detected in 22,653 cases. Antibody frequencies in these cases were as follows: anti-E, 26.8%; anti-Lea, 20.0%; anti-P1, 7.1%; anti-M, 6.4%; anti-Mia, 5.6%; anti-c + E, 5.6%; anti-Leb, 4.6%; anti-D, 2.8%; anti-Fyb, 2.6%; anti-Lea+Leb, 2.5%; anti-Dia, 2.0%; and others. For pregnant patients, anti-D (12.7%) was statistically more frequent. For transfused patients, anti-E (37.3%), anti-c + E (9.5%), anti-C + e (3.3%) and anti-Jka (3.1%) were significantly more frequent.

Outcomes of allogeneic hematopoietic cell transplantation in acute myeloid leukemia patients with monosomal karyotypes.

This study investigated the outcomes of allogeneic hematopoietic cell transplantation (allo-HCT) in acute myeloid leukemia (AML) patients with monosomal karyotypes (MK). A total of 114 AML patients who received allo-HCT were retrospectively analyzed. At the time of diagnosis, 13 patients were categorized with a favorable cytogenetic risk, 78 with an intermediate risk, and 23 with an adverse risk. MK was found in 12 patients among 23 with adverse cytogenetic risk. Pretransplant disease status was active disease in 5 cases (45.5%) in the adverse-risk without MK group, and 8 cases (66.7%) in the corresponding group with MK, 15 (19.2%) in the intermediate group and 4 (30.8%) in the favorable group. In multivariate analysis, active disease before transplant (hazard ratio, HR 3.913, p < 0.001), acute graft-versus-host disease (GVHD) ≥grade 2 (HR 1.908, p = 0.048) and chronic GVHD (HR 0.364, p = 0.001) affected overall survival (OS). The initial cytogenetic risk groups were not a significant risk factor for OS in allogeneic settings. The 2-year OS rate was 44.0 ± 15.9% without MK and 20.7 ± 17.9% with MK (p = 0.246). However, the OS rate was better for patients with chronic GVHD (p = 0.025). In conclusion, a survival benefit was observed for MK-positive patients with chronic GVHD in an allogeneic setting. However, the prognosis still remained poor for patients with MK.

Benefits of fresh-frozen plasma as a replacement fluid to neutralize ABO antibodies.

BACKGROUND: ABO-incompatible organ transplantation requires pre-transplant conditioning to reduce ABO antibody levels in the recipients. With respect to replacement fluids used in plasma exchange, we intended to verify whether fresh-frozen plasma (FFP) containing soluble ABO substance (SAS) is more effective than albumin solution in reducing ABO IgG antibody levels. METHODS: Apheresis data were retrospectively studied for in vivo effects, and in vitro plasma mixing studies were prospectively performed. The amount of ABO IgG antibodies bound to red cells was measured as the mean fluorescence intensity (MFI) using flow cytometry. Neutralization of ABO antibodies in the recipientst plasma by an ABO-incompatible donornc plasma was measured using the inhibition assay principle. The MFI value of the unneutralized control tube was divided by that of the neutralized test tube (neutralizing-capacity index, NCI). RESULTS: The plasma exchange procedures replaced with group AB FFP showed a significantly greater decreased titer than those replaced with albumin (P = 0.010). The in vitro plasma mixing study simulating plasma exchange also produced consistent results. When the pooled group O plasma was neutralized for anti-A by individual group AB plasmas (AB-to-O, N = 30), the NCI was 12.8 ± 5.4 (6.5-29.5). When this group O plasma was neutralized by pooled group AB or A plasma, the repeatedly measured NCI (N = 5) of A-to-O (11.4 ± 1.4) was not significantly different from that of AB-to-O (9.7 ± 1.3, P = 0.074). CONCLUSIONS: ABO antibody levels are reduced more effectively by group AB FFP than by albumin. Either group AB or donor type (group A or B) FFP can be infused to group O recipients. FFP units with higher SAS levels can be selected from multiple available candidate units using our protocol for measuring the neutralizing-capacity.

Pilot study on combination of azacitidine and low-dose cytarabine for patients with refractory anemia with excess blast.

This study analyzed the outcomes of the combination of azacitidine and low-dose cytarabine in patients newly diagnosed with refractory anemia with excess blast (RAEB). Patients were treated with azacitidine 75 mg/m(2) for 7 days subcutaneously and cytarabine 20 mg/m(2) intravenously for 7 days every 28 days. The assigned regimen was repeated for two cycles, then the patients treated with azacytidine alone until progression or allogeneic stem cell transplantation (allo-SCT). Eighteen patients with 5 RAEB-1 and 13 RAEB-2 were enrolled in the current study. After two cycles of the combination therapy, responses were achieved in nine patients (50.0%): four complete response (CR) (22.2%), one partial response (5.6%), two marrow-CR (11.1%), and two hematologic improvement (11.1%). Four patients (22.2%) progressed to acute leukemia during two cycles of the combination therapy. The 1-year overall survival (OS) was 87.5% for the early response group (responses at two cycles) and 0% for the late response group (responses at four cycles, p = 0.042). Plus, the median survival time was 476 days (range, 37-718 days) for the early response group and 221 days (range, 193-249 days) for the late response group. The 1-year OS was 100% for the patients who underwent allo-SCT and 73.4% for those without allo-SCT. In summary, the combination therapy showed promising response rate when compared to treatment with azacitidine alone. However, it was limited in terms of preventing leukemic transformation. Allo-SCT would seem to be the only available treatment that can alter disease progression.

Comparing SARS-CoV-2 Antibody Responses after Various COVID-19 Vaccinations in Healthcare Workers.

Coronavirus disease 2019 (COVID-19) vaccination began for healthcare workers in South Korea at the end of February 2021. This study investigated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses after various COVID-19 vaccinations in healthcare workers. Blood specimens of 497 vaccinated healthcare workers were collected. Inoculated vaccines were ChAdOx1 (AstraZeneca/Oxford), BNT162b2 (Pfizer/BioNTech), JNJ-78436735 (Janssen), and mRNA-1273 (Moderna). Each specimen was tested for antibodies against SARS-CoV-2 using Elecsys Anti-SARS-CoV-2 S assay (Roche Diagnostics), SARS-CoV-2 IgG II Quant assay (Abbott), and R-FIND SARS-CoV-2 Neutralizing Antibody kit (SG medical Inc.). A questionnaire was used to investigate adverse events related to vaccination. We found that 99.5% of the subjects showed a 96-100% positive rate in all three antibody assays, regardless of the vaccine type. The antibody-positive rate of completed vaccination groups reached 96-100%, and antibody quantities significantly increased 2 weeks after vaccination. The antibody values measured approximately 3 months after BNT162b2 inoculation significantly correlated with adverse events.

Genome-wide high density single-nucleotide polymorphism array-based karyotyping improves detection of clonal aberrations including der(9) deletion, but does not predict treatment outcomes after imatinib therapy in chronic myeloid leukemia.

The current study investigated molecular cytogenetic characteristics of chronic myeloid leukemia (CML) using genome-wide, single nucleotide polymorphism arrays (SNP-A) capable of detecting cryptic submicroscopic genomic aberrations. Genome-Wide Human SNP 6.0 Array (Affymetrix, CA, USA) was performed in 118 patients having CML, chronic phase. Thirty-nine clonal aberrations (CAs) were identified (35 losses, two gains, two copy neutral loss of heterozygosity) that were not detected by metaphase cytogenetics in 25 patients (21%). The 9q34 deletions were found in 10% of cases, while 22q11.2 deletions were observed in 12% of cases. Seven patients (6%) harbored both 5'-ABL and 3'-BCR deletions adjacent to the t(9;22) breakpoint. Copy number gains were identified at 8p and 9p, and losses at 2q, 7q, 8q, 9q, 11q, 13q, 16p, and 22q. When we compared the treatment outcome of imatinib therapy between patients with and without CAs identified by SNP-A, treatment failure and progression to advanced disease were not significantly different (p > 0.05). In addition, according to the presence of deletions of 9q34 and/or 22q11.2 identified by SNP-A, the treatment outcome did not show any significant differences (p > 0.05). Our data suggests that SNP-A analysis is a useful tool for detection of clonal aberrations including deletions adjacent to the t(9;22) breakpoint in the CML cancer genome. However, clonal aberrations detected by SNP-A could not improve a prognostic stratification in CML patients with chronic phase.

Cryopreservation of amniotic fluid-derived stem cells using natural cryoprotectants and low concentrations of dimethylsulfoxide.

Amniotic fluid-derived stem cells (AFSCs) are a potential cell source for therapeutic applications. They can be easily mass produced, cryopreserved and shipped to clinics for immediate use. However, one major obstacle to the manufacturing of clinical grade stem cells is the need for current good manufacturing practices for cryopreservation, storage, and distribution of these cells. Most current cryopreservation methods used for stem cells include the potentially toxic cryoprotectant (CPA) dimethylsulfoxide (Me(2)SO) in the presence of animal serum proteins that prevent direct use of these cells in human therapeutic applications. To avoid any potential cryoprotectant related complications, it will be essential to develop non-toxic CPAs or reduce CPA concentration in the freezing media used. In this study, we assessed the use of disaccharides, antioxidants and caspase inhibitors for cryopreservation of AFSCs in combination with a reduced concentration of Me(2)SO. The thawed cells were tested for viability with MTT assays and a growth curve was created to measure population doubling time. In addition, we performed flow cytometry analysis for cell surface antigens, RT-PCR for mRNA expression of stem cell markers, and assays to determine the myogenic differentiation potential of the cells. A statistically significant (p<0.05) increase in post-thawed cell viability in solutions containing trehalose, catalase and (Z)VAD-fmk with 5% Me(2)SO was observed. The solutions containing trehalose and catalase with 5% or 2.5% (v/v) Me(2)SO produced results similar to those for the control (10% (v/v) Me(2)SO and 30% FBS) in terms of culture growth, expression of cell surface antigens and mRNA expression of stem cell markers in AFSCs cryopreserved for a minimum of 3 weeks. Thus, AFSCs can be cryopreserved with 1/4 the standard Me(2)SO concentration with the addition of disaccharides, antioxidants and caspase inhibitors. The use of Me(2)SO at low concentrations in cell freezing solutions may support the development of clinical trials of AFSCs.

Novel ELANE gene mutation in a Korean girl with severe congenital neutropenia.

Severe congenital neutropenia is a heterozygous group of bone marrow failure syndromes that cause lifelong infections. Mutation of the ELANE gene encoding human neutrophil elastase is the most common genetic alteration. A Korean female pediatric patient was admitted because of recurrent cervical lymphadenitis without abscess formation. She had a past history of omphalitis and isolated neutropenia at birth. The peripheral blood showed a markedly decreased absolute neutrophil count, and the bone marrow findings revealed maturation arrest of myeloid precursors at the promyelocyte to myelocyte stage. Her direct DNA sequencing analysis demonstrated an ELANE gene mutation (c.607G > C; p.Gly203Arg), but her parents were negative for it. She showed only transient response after subcutaneous 15 µg/kg/day of granulocyte colony stimulating factor administration for six consecutive days. During the follow-up observation period, she suffered from subsequent seven febrile illnesses including urinary tract infection, septicemia, and cellulitis.

Characterization of the novel DQA1*01:01:09 allele by next-generation sequencing.

HLA-DQA1*01:01:09 differs from HLA-DQA1*01:01:01:01 by one nucleotide substitution in codon-12 in exon 1.

Erythrocyte deformability reduction in various pediatric hematologic diseases.

BACKGROUND: Previously, hemorheology studies using Rheoscan mainly focused on chronic kidney disease, cardiovascular disease, and endocrine disease in adults. The study using LORCA focused on erythrocyte disease. There were no studies using Rheoscan in children. OBJECTIVE: We aimed to investigate erythrocyte deformability among various hematologic diseases occurring in children, namely, iron deficiency anemia (IDA), hereditary spherocytosis (HS), immune thrombocytopenia (ITP), and aplastic anemia (AA). METHODS: Differences between those with HS, IDA, ITP, AA and healthy controls were compared among 43 patients, comprising 7 patients with HS, 8 patients with IDA, 6 patients with AA, 9 patients with ITP, and 13 healthy controls. Erythrocyte deformability was measured using a microfluidic ektacytometer (RheoScan-D, RheoMeditech, Seoul, Korea). The erythrocyte elongation index (EI) was defined as (L - W)/(L + W), where L and W are the major and minor axes of the ellipse, respectively. RESULTS: The EI values of IDA, HS and AA were significantly decreased compared with healthy controls, but those of ITP were similar to healthy controls. CONCLUSIONS: This study showed that erythrocyte deformability differed among various hematologic diseases. Further study concerning correlation in relation to the diagnostic and prognostic significance of erythrocyte deformability in hematologic disease is needed.

COVID-19 transmission and blood transfusion: A case report.

The recent outbreak of the novel coronavirus disease 2019 (COVID-19) has been labelled as a pandemic by the World Health Organization. Although person-to-person transmission of the etiologic agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been confirmed, it is not known whether COVID-19 may be transmitted by blood transfusion. Notwithstanding the urgent requirement of blood, it is critical to know whether the SARS-CoV-2 virus can be transmitted by blood transfusion because many individuals may be asymptomatic carriers and may donate blood. Several cases in which specific viral RNA could be detected in the serum from patients with COVID-19 have already been reported; these findings suggest that blood donation may be an unexplored route of transmission. However, the American Association of Blood Banks and Centers for Disease Control and Prevention have not recommended any specific SARS-CoV-2-related actions to be taken at blood collection centres at this time. In this report, we describe a case of a 21-year-old man with very severe aplastic anaemia who received apheresis platelet transfusion from an individual who was subsequently diagnosed with COVID-19. Our patient tested negative for COVID-19 and is awaiting allogeneic stem cell transplantation.

Mobilization effects of G-CSF, GM-CSF, and darbepoetin-alpha for allogeneic peripheral blood stem cell transplantation.

The effects of GM-/G-CSF and darbepoetin-alpha on stem cell mobilization were investigated. From February 2005 to March 2007, 30 allogeneic sibling donors were randomly assigned to a G-CSF group (5 microg/kg/day for 5-7 days) or triple group (GM-CSF 10 microg/kg/day on 1st and 2nd day, G-CSF 5 microg/kg/day for 5-7 days, and darbepoetin-alpha 40 mg on 1st day). The MNCs and CD34(+) cells were not different between the two groups, although the doses (x10(8)/kg of recipient body weight) of CD3(+) cells (3.64 +/- 1.75 vs. 2.63 +/- 1.36, P = 0.089) and CD8(+) cells (1.07 +/- 0.53 vs. 0.60 +/- 0.30, P = 0.006) were lower in the triple group. The engraftments, frequency of RBC transfusions, and hemoglobin recovery were not different between the two groups. The cumulative incidence of overall and Grades II-IV aGVHD was 64.3% vs. 61.1% and 25.9% vs. 27.1% in the G-CSF and triple regimen group, respectively, whereas the cumulative incidence of cGVHD was 20.8 +/- 1.3% and 24.4 +/- 1.7%, respectively. In conclusion, the triple regimen did not seem to be superior to G-CSF alone in terms of the CD34+ cell dose, hemoglobin recovery, and GVHD. However, the CD8+ cell count was significantly lower in the triple regimen group. The role of a lower CD8+ cell count in the graft may need to be elucidated in the future.

Measurement of erythrocyte aggregation in a microchip stirring system by light transmission.

In the analysis of red blood cell (RBC) aggregation using optical detection, various shearing methods have been used to disperse RBCs in confined geometries. This study investigated RBC aggregation measurement in a microchip-stirring system by analysis of light transmission. A stirring-aided disaggregation mechanism in a microchip, consisting of a flat-cylindrical test chamber (D=4 mm, H=0.3 mm) and a magnetic stirrer (d=0.14 mm, l=2.2 mm), was used to generate a given shear which was large enough to disperse RBC aggregates, but not large enough to cause any mechanical hemolysis of cells. After stirring for 10 s followed by an abrupt halt of the stirring, the intensity of the light transmitted through a microchip was measured with respect to time and analyzed. A comparative study was conducted with varying test chamber height and hematocrit. The AI and t1/2 as typical aggregation indices obtained by analysis of transmitted light, which showed a good reproducibility (coefficient of variation (CV)<2.8%, n=10), also were found to be nearly independent of the chamber dimensions (CV<3.4%). The present aggregometry also showed the similar results of aggregation indices with varying hematocrits compared to those obtained using a laser-assisted optical rotational cell analyzer (LORCA). The essential feature of the present design is the adoption of a disposable microchip requiring a minimum blood sample volume as small as 6 mul, which enables it to be used easily in a clinical setting.

A transient, microfluidic approach to the investigation of erythrocyte aggregation: the threshold shear-stress for erythrocyte disaggregation.

Detailed analysis of red blood cells (RBCs) aggregation is often required in various clinical studies. Most conventional aggregation indices are dimensionless values and not available for comparison of across studies. Quite recently, we have developed microfluidic aggregometry that enables us to yield a critical shear-stress that are required to aggregate RBCs under the shearing hydrodynamic force. The present study investigated the relationships between the values of the critical shear-stress and conventional aggregation indices by comparing the critical shear-stress measured by the microfluidic aggregometry with the threshold shear-stress measured using a LORCA aggregometer. The results showed that the critical shear-stress did not vary with the hematocrit value while the threshold shear-rate decreased with the hematocrit value. The threshold shear-stress also showed the same hematocrit-independence as the critical shear-stress. These findings assist in rheologically validating the critical shear-stress, as defined in the microfluidic aggregometry, within the present range of hematocrit values.

Favorable long-term survival using consolidation chemotherapy without allogeneic hematopoietic cell transplantation for acute myeloid leukemia with wild-type NPM1 without FLT3-ITD.

BACKGROUND: The role of allogeneic hematopoietic cell transplantation (allo-HCT) compared with consolidation chemotherapy alone in intermediate-risk acute myeloid leukemia (AML) patients with wild-type nucleophosmin/negative or a low level of Fms related tyrosine kinase 3 internal tandem duplication (NPM1 wt/FLT3-ITDneg/low) has not yet been elucidated. METHODS: In this study, we retrospectively investigated 88 patients newly diagnosed with AML who received intensive induction chemotherapy at Kyungpook National University Hospital from March 2015 to July 2017. The selection criteria included the presence of results on genetic abnormalities including NPM1 and FLT3-ITD. RESULTS: According to the European LeukemiaNet (ELN) risk classification, 25 patients (28%) were categorized as favorable, 44 (50%) as intermediate, and 19 (22%) as adverse risk. Among the intermediate-risk patients, 40 were identified as NPM1 wt/FLT3-ITDneg/low. Among the patients with NPM1 wt/FLT3-ITDneg/low, complete remission (CR) was achieved in 26 patients out of 40 (65%). One-year overall survival (OS) rate was 100% in the favorable-risk group and 87.9% in the NPM1 wt/FLT3-ITDneg/low group (P=0.233). Among the intermediate-risk NPM1 wt/FLT3-ITDneg/low patients, there was no survival benefit with allo-HCT (N=19) compared to consolidation chemotherapy (N=21; P=0.372). In the multivariate analysis, the ELN risk group [hazard ratio (HR), 6.36; P=0.019] and the achievement of CR (HR, 2.95; P=0.017) were both identified as factors affecting OS of patients with newly diagnosed AML. CONCLUSION: Among the AML patients, intermediate-risk NPM1 wt/FLT3-ITDneg/low patients and favorable-risk patients showed similar OS rates. Our results suggested that allo-HCT might have limited clinical benefit for the intermediate-risk NPM1 wt/FLT3-ITDneg/low patients. Well controlled studies are needed to confirm the current results.

Rheological characteristics of erythrocytes incubated in glucose media.

Glucose-rich plasma is commonly observed in diabetes mellitus and in-vitro incubation of erythrocytes in glucose-rich media may produce the non-enzymatic glycosylation of erythrocyte proteins. The present study investigates the effects of an increased concentration of glucose in a suspending medium on erythrocyte rheological parameters. Erythrocytes, which were obtained from ten healthy volunteers, were washed and incubated in vitro with glucose solutions at different concentrations and incubation times. The measured hemorheological parameters included deformability and the aggregation of erythrocytes. Hemoglobin concentration in the erythrocyte suspension in autologous plasma was also measured after incubation in order to assess the hemolysis of erythrocytes. Significant hemorheological changes were observed with an increase of glucose concentration and incubating time. Both deformability and the aggregation of erythrocytes decreased in dose- and time-dependent manner. A reduction in hemoglobin concentration in the erythrocyte suspensions was also observed due to hemolysis of fragile erythrocytes during incubation. Modification in the hemorheological properties of cells, which may be associated with due to glucose-induced (auto)oxidation and glycation of erythrocyte proteins in hyperglycemia, can adversely affect the fluidity and oxygen-delivery function of the erythrocytes.

Susceptibility of oxidative stress on red blood cells exposed to gamma rays: hemorheological evaluation.

Irradiation has been shown to induce biochemical changes in stored red blood cells (RBCs) and to generate reactive oxygen species (ROS). This study evaluated the hemorheological properties, the degree of lipid peroxidation and the oxidative susceptibility of irradiated RBCs. Furthermore, we investigated the radioprotective role of N-t-butyl hydroxylamine (NtBHA) against gamma-ray exposure of RBCs. RBC concentrates were irradiated with a minimum dose of 25 Gy, and were exposed to FeSO4 to examine the oxidative susceptibility. RBC deformability was evaluated by the use of a microfluidic ektacytometer, in relation to the hematological and biochemical properties. The deformability of the irradiated RBCs was significantly lower than that of control. Exposure to gamma rays significantly increased the mean corpuscular volume (MCV) and lipid peroxidation. Changes in RBC deformability were more prominent in irradiated RBCs than in non-irradiated RBCs also under conditions of oxidative stress. The deformability of NtBHA treated RBCs prior to irradiation was not altered as compared with irradiated RBCs not treated with NtBHA. In conclusion, irradiation reduces RBC deformability during storage and the irradiated RBCs seem susceptible to oxidative stress. NtBHA may not have a protective role against the effects of gamma-ray exposure in RBCs but further evaluation of NtBHA or another radioprotective compound is required.