Improving the quality of washed and buffy coat-free erythrocyte concentrates]

Washing buffy-coat free erythrocyte concentrates three times in bottles used for blood storage will diminish their leukocyte content to 0.22 +/- 0.11 x 10(9) per TE (= 9% of the initial value in whole blood, and the thrombocyte content to 0.3 +/- 0.5 x 10(9) per day (= 2% of the initial value in whole blood). Even 50% of leukocytes (mainly lymphocytes) and 80% of thrombocytes are eliminated simply by buffy coat separation. 30% of erythrocytes are lost by the washing process. Due to increasing haemolysis (0.22%) a subsequent storage of 24 hours should not be exceeded for washed erythrocyte concentrates. Further quality parameters, such as morphological index, pH, ATP, 2,3-P2G and K+ and Na+, were investigated. As far as selected quality parameters are concerned, washing erythrocyte concentrates three times in bottles for blood storage may be compared with washing them once in blood bags. The present findings confirm the conclusion that the washing of erythrocyte concentrates with a solution of sodium chloride in order to eliminate leukocytes may for the most part exclude non-haemolytic febrile transfusion reactions, but not immunization. More effective procedures of eliminating leukocytes, such as filtration, TTK or even glycerin, treatment of erythrocyte concentrates without cryoconservation, are indispensable.     

Electron microscopy for the diagnosis of tumours.

The role of leukocyte transfusions in the prevention and treatment of infections in adults with granulocytopenia was investigated. Leukocytes were obtained from healthy volunteers by continuous-flow centrifugation. Histocompatibility antigen (HLA)-matched leukocytes were used to assess the prophylactic value of leukocyte transfusions. Seven patients with acute myelogenous leukemia received HLA-matched leukocytes during the period of maximal granulocytopenia associated with initial remission induction therapy; 20 concurrently treated patients who did not receive leukocyte transfusions were the control group. The patients receiving HLA-matched leukocytes had significantly fewer (P = 0.043) infectious episodes (not bacteriologically proven) during the study period, and remission occurred in 5 of the 7, compared with 10 of the 20 controls. In addition, 52 series of two or more ABO-compatible transfusions were given to 50 patients with proven infection or elevated temperature presumed due to infection and a granulocyte count of less than 0.5 X 10(9)/L. Response, indicated by a decrease in temperature, occurred in 23 patients. Leukocyte transfusions thus have an important adjuvant role in the management of patients with severe granulocytopenia.     

The growth of Listeria monocytogenes in cheese packed under a modified atmosphere

The effect of modified atmosphere Packaging (MAP) on the growth of Listeria monocytogenes in mould ripened cheeses was studied at refrigeration temperatures (2-8.3 degrees C) over a storage period of 6 weeks. Control experiments in cling film with no atmospheric modification produced a lag time before growth of up to 1 week and rapid subsequent growth. MAP with a CO2 concentration of less than 20% allowed growth to occur but when O2 was incorporated; the lag time was reduced from 3 to 2 weeks and subsequent growth was also faster, producing an increase in cell numbers of 1.4 log cycles over the incubation period. N2-MAP in the absence of O2 increased the lag time to 3 weeks and slowed growth, while the inclusion of CO2 extended the lag to 3 weeks and slowed subsequent growth even more. In MAP with 80:10:10 (v/v/v) N2:CO2:O2, there was a lag period of 2-3 weeks before growth of L. monocytogenes occurred, while the total viable aerobic count (TVAC) decreased by 2-3 log cycles and the total Lactobacillus count showed little change. It was concluded that MAP was not suitable for preventing the growth of L. monocytogenes in such cheeses.     

Optimization of an acoustic cell filter with a novel air-backflush system

Increasing worldwide demand for mammalian cell production capacity will likely be partially satisfied by a greater use of higher volumetric productivity perfusion processes. An important additional component of any perfusion system is the cell retention device that can be based on filtration, sedimentation, and/or acoustic technologies. A common concern with these systems is that pumping and transient exposure to suboptimal medium conditions may damage the cells or influence the product quality. A novel air-backflush mode of operating an acoustic cell separator was developed in which an injection of bioreactor air downstream of the separator periodically returned the captured cells to the reactor, allowing separation to resume within 20 s. This mode of operation eliminated the need to pump the cells and allows the selection of a residence time in the separator depending on the sensitivity of the cell line. The air-backflush mode of operating a 10L acoustic separator was systematically tested at 10(7) cells/mL to define reliable ranges of operation. Consistent separation performance was obtained for wide ranges of cooling airflow rates from 0 to 15 L/min and for backflush frequencies between 10 and 40 h(-1). The separator performance was optimized at a perfusion rate of 10 L/day to obtain a maximum separation efficiency of 92 +/- 0.3%. This was achieved by increasing the power setting to 8 W and using duty cycle stop and run times of 4.5 and 45 s, respectively. Acoustic cell separation with air backflush was successfully applied over a 110 day CHO cell perfusion culture at 10(7) cells/mL and 95% viability.     

Depression of early protection against influenza virus infection by cyclophosphamide and its restoration by Y-19995 [2,4'-bis(1-methyl-2-dimethyl-aminoethoxyl)-3-benzoylpyridine dimaleate

The relationship between depression of early protection against influenza virus infection and the decrease in the number of peripheral polymorphonuclear leukocytes in cyclophosphamide-treated mice was investigated by means of a novel synthetic compound, Y-19995 [2,4'-bis(1-methyl-2-dimethyl-aminoethoxyl)-3-benzoylpyridine dimaleate], which had been shown to exert a potent restorative effect on leukocytopenia in immunocompromised hosts. Following intranasal inoculation with influenza virus (1.5 x 10(3) plaque-forming units) into untreated mice, the pulmonary virus titer progressively increased during 3 days and decreased gradually from day 7 after infection. The treatment with cyclophosphamide 2 days before infection markedly enhanced the pulmonary virus multiplication from the early phase of infection, and the higher virus titer was maintained thereafter. When mice were given Y-19995 after cyclophosphamide treatment, virus titers from the early to late phases of infection were lower than those in untreated mice. The number of peripheral polymorphonuclear leukocytes in cyclophosphamide-treated mice rapidly decreased and returned to normal levels only 9 days after the treatment, while such leukocytopenia was prevented to some extent and the leukocyte count was restored completely up to 7 days by postcyclophosphamide treatment with Y-19995. Furthermore, the treatment with Y-19995 augmented the inactivation of virus by the polymorphonuclear leukocytes. However, the virus inactivation by alveolar macrophages was modified only slightly by Y-19995 treatment. In addition, Y-19995 treatment could potentiate antibody-dependent cell-mediated cytotoxicity of polymorphonuclear leukocytes against the virus-infected target cells, and the production of serum neutralizing antibody to influenza virus in untreated and cyclophosphamide-treated mice. Y-19995 revealed neither antiviral nor interferon-inducing activities.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preparation of leukocyte-poor erythrocyte concentrates using a simple aspiration technic

Depletion of leukocytes from red blood cells can prevent transfusion reactions in HLA-sensitized patients. We describe a simple technique of aspiration of the buffy-coat after centrifugation of red blood cells concentrates, less than 6 days old. This method can remove 87% of the leukocytes. The average leukocyte count after aspiration is 2 x 10(8). This method is inexpensive and does not require any special equipment.     

Membrane proteins in Rh+, Rh- and Rh: -29, 38 (- - -/- - -, rh) red cells compared by using SDS-polyacrylamide gel electrophoresis

Since Rh: -29, 38 (- - -/- - -, rh) phenotype of the Rh blood groups (--- in text) revealed unusual red cells, such as stomatocytes and microspherocytes and the relatively shortened half life of 17 days, red cell membrane proteins from Rh + (D), Rh - (d) and --- were compared by using SDS-polyacrylamide gel electrophoresis (SDS-PAGE). No differences were observed among the patterns of the reduced and non-reduced membrane proteins from Rh+, Rh- and --- red cells. Two-dimensional gel electrophoresis of --- red cell membrane proteins also revealed a pattern similar to Rh+ and Rh- red cell membrane proteins. It is suggested that the lack of all Rh antigens causes no visible alteration of red cell membrane proteins detected by the method of Fairbanks G., Steck T.L. and Wallach D.F.H. (1971) Biochemistry, N.Y. 10, 2606-2617.     

The zonal centrifuge applied to the purification of a low-yield virus in human leukemia cells

The herpes-type virus found in certain cell cultures derived from Burkitt's lymphoma, other human leukemias, and normal human leukocytes, was concentrated and partially purified by large-volume density gradient centrifugation using zonal centrifuge systems. Using the Jiyoye (P-3) cell line as a model, rate-zonal runs on disrupted cell suspensions in sucrose gradients yielded concentrates with high virus particle counts when 10–15 ml of packed cells were processed per liter of gradient. Isolation and removal of cell nuclei or fluorocarbon treatment of cell sonicates permitted virus recovery from larger volumes of cells per experiment. Zonal centrifugation of concentrated cell-free spent media from highly infected cell cultures yielded more purified virus than obtained from cells. Viral concentrates were prepared with particle counts of 10¹⁰–10¹¹/ml and total protein concentrations of 0.2–0.5 mg/ml. Subsequent isopyenie-zonal centrifugation of the various high-count virus fractions from the zonal centrifuge showed a heterogeneity in buoyant virus density ranging from 1.18 to 1.27 in potassium tart rate. The spread in virus density was attributed to the different morphological forms of the virus observed by electron microscopy.     

Comparison of the effect of calcium gluconate and batroxobin on the release of transforming growth factor beta 1 in canine platelet concentrates

ABSTRACT: BACKGROUND: The clinical use of autologous platelet concentrates (also known as platelet-rich plasma) on the field of regenerative therapy, in the last decade has been the subject of several studies especially in equine medicine and surgery. The objectives of this study was: 1) to describe and compare the cellular population in whole blood, lower fraction (A) and upper fraction (B) of platelet concentrates, 2) to measure and compare the transforming growth factor beta 1 (TGF-beta1) concentration in plasma and both platelet concentrates after be activated with calcium gluconate or batroxobin plus calcium gluconate and, 3) to determine correlations between cell counts in platelet concentrates and concentrations of TGF-beta1. Blood samples were taken from 16 dogs for complete blood count, plasma collection and platelet concentrates preparation. The platelet concentrates (PC) were arbitrarily divided into two fractions, specifically, PC-A (lower fraction) and PC-B (upper fraction). The Platelet concentrates were analyzed by hemogram. After activated with calcium gluconate or batroxobin plus calcium gluconate, TGF-beta1 concentration was determined in supernatants of platelet concentrates and plasma. RESULTS: There were differences statistically significant (P < 0.05) for the platelet count and leukocyte count and TGF-beta1 concentration between whole blood, plasma and both platelet concentrates. A significant correlation was found between the number of platelets in both platelet concentrates and TGF-beta1 concentration. Platelet collection efficiency was 46.34% and 28.16% for PC-A and PC-B, respectively. TGF-beta1 concentration efficiency for PC activated with calcium gluconate was 47.75% and 31.77%, for PC-A and PC-B, respectively. PC activated with batroxobin plus CG showed 46.87% and 32.24% for PC-A and PC-B, respectively. CONCLUSIONS: The methodology used in this study allows the concentration of a number of platelets and TGF-beta1 that might be acceptable for a biological effect for clinical or experimental use as a regenerative therapy in dogs.     

Depression,changes in peripheral blood cell count,and changes in selected biochemical parameters related to lead concentration in whole blood (Pb-B) of women in the menopausal period

The aimThe aim of this study was to assess the severity of depression, vasomotor symptoms, changes in peripheral blood cell count, and selected biochemical parameters in relation to the concentration of lead in whole blood of women in the perimenopausal period.MethodsThe study sample consisted of 233 women from the general population of the West Pomeranian Province (Poland) in age between 44–65 years. The intensity of menopausal symptoms was examined using the Blatt-Kupperman Index, and the severity of depression using the Beck Depression Inventory. The following biochemical data were evaluated: concentrations of glucose, triglycerides, HDL, C-reactive protein, glycated haemoglobin, cortisol, insulin, blood cell count, and lead concentration in whole blood (Pb-B).ResultsA whole blood Pb concentration below 5 μg/dl was found in 55 subjects (23.61 %), in 142 women (60.94 %) it ranged from 5 to 10 μg/dl, while in 36 women (15.45 %) was higher than 10 μg/dl. There was a strong positive correlation between Pb concentration in the blood of the examined women and the severity of depressive symptoms (Rs=+0.60, p = 0.001). The lowest mean values for total leukocytes (5.07 ± 1.22 thousand/μl) and neutrophils (2.76 ± 0.86 thousand/μl) were found in women with Pb concentration above 10 μg/dl (p < 0.05). There was a significant negative correlation between the number of total leukocytes (r=-0.45, p = 0.002) and neutrophils (r=-0.50, p = 0.001) and blood Pb concentration. Analysis showed statistically significant differences in glucose concentration (p < 0.05) between groups. Blood glucose was higher in women with Pb-B <5 and between 5−10 μg/dl than in women with Pb-B >10 μg/dl.ConclusionExposure to Pb may be a factor playing a significant role in the development of depressive symptoms in menopausal women. It may also be associated with glucose metabolism disorders and immunosuppression in women during this period of life.     

Hyperventilation-induced changes of the blood picture

In a controlled study of 11 male volunteers the following changes (means +/- SD) were observed in venous blood during (D) and 75 min after (A) a period of 20 min of voluntary hyperventilation in comparison with before (B) hyperventilation (P values referring to the difference between D and B) erythrocyte count 5.18 +/- 0.17 X 10(6) (B), 5.70 +/- 0.21 X 10(6) (D) (P less than 0.001), and 5.18 +/- 0.16 X 10(6)/microliter (A); hemoglobin 15.7 +/- 0.6 (B), 17.2 +/- 0.7 (D) (P less than 0.001), and 15.8 +/- 0.6 g/dl (A); centrifuged hematocrit 46.6 +/- 1.0 (B), 50.4 +/- 1.7 (D) (P less than 0.001), and 47.0 +/- 1.8% (A). The platelets increased from 159 +/- 30 X 10(3) (B) to 205 +/- 40 X 10(3) (D) (P less than 0.001) and returned to 157 +/- 26 X 10(3)/microliter (A). The leukocytes (WBC) were 4,210 +/- 630 (B), 6,220 +/- 1,660 (D) (P less than 0.001), and 6,190 +/- 1,870/microliter (A) (P less than 0.002, as compared with B). The rise of WBC during hyperventilation was mainly due to a 83% increase of lymphocytes, whereas a 93% increase of neutrophil leukocytes accounted for the increased WBC 75 min posthyperventilation. The increase of the ratio of band forms to segmented neutrophils from 9 (B) to 19% (A) (P less than 0.01) indicates that band forms were released from the bone marrow. The results show that WBC and platelets can be mobilized by hyperventilation by as yet unidentified mechanisms.     

The cytology of the pouch of Douglas in polycystic ovarian disease

Cul-de-sac aspiration was performed for cytologic sampling in 137 cases of polycystic ovaries treated by wedge resection. Fifty patients undergoing abdominal tubal ligations also underwent aspiration of the pouch of Douglas as a control group. The cytodifferential count in polycystic ovarian disease showed 30% to 40% mesothelial cells, 15% to 20% polymorphonuclear leukocytes, 15% to 20% lymphocytes, 10% to 15% squamous cells and 1% to 5% histiocytes. The corresponding count in the control group showed 15% to 20% mesothelial cells, 20% to 25% polymorphonuclear leukocytes, 15% to 20% lymphocytes, 10% to 15% squamous cells and 1% to 3% histiocytes. Cells exfoliated from the fimbrial end of the tube were encountered in most smears. Abnormal cells were diagnosed in seven cases of polycystic ovarian disease due to a coexistent neoplasm, i.e., two dermoid cysts, a carcinoid tumor, a hilus cell tumor, a simple serous cyst, a pseudomucinous cystadenoma and endometriosis of the ovary. All tumors were histologically diagnosed in the resected wedges of the ovaries.     

Characterization and optimization of acoustic filter performance by experimental design methodology

Acoustic cell filters operate at high separation efficiencies with minimal fouling and have provided a practical alternative for up to 200 L/d perfusion cultures. However, the operation of cell retention systems depends on several settings that should be adjusted depending on the cell concentration and perfusion rate. The impact of operating variables on the separation efficiency performance of a 10-L acoustic separator was characterized using a factorial design of experiments. For the recirculation mode of separator operation, bioreactor cell concentration, perfusion rate, power input, stop time and recirculation ratio were studied using a fractional factorial 2(5-1) design, augmented with axial and center point runs. One complete replicate of the experiment was carried out, consisting of 32 more runs, at 8 runs per day. Separation efficiency was the primary response and it was fitted by a second-order model using restricted maximum likelihood estimation. By backward elimination, the model equation for both experiments was reduced to 14 significant terms. The response surface model for the separation efficiency was tested using additional independent data to check the accuracy of its predictions, to explore robust operation ranges and to optimize separator performance. A recirculation ratio of 1.5 and a stop time of 2 s improved the separator performance over a wide range of separator operation. At power input of 5 W the broad range of robust high SE performance (95% or higher) was raised to over 8 L/d. The reproducible model testing results over a total period of 3 months illustrate both the stable separator performance and the applicability of the model developed to long-term perfusion cultures.     

Leukocyte-depleted blood: a comparison of available preparations.

Febrile nonhemolytic transfusion reactions due to leukoagglutinins are frequently seen in patients who have been given multiple blood transfusions. To prevent or reduce the severity of these reactions, leukocyte-poor blood (that containing fewer than 0.3 X 10(9) leukocytes per unit) is frequently requested by clinicians. Four methods commonly used in Canada to produce leukocyte-poor blood were examined for their relative effectiveness and appropriate use. The mean total leukocyte count per unit was reduced to 0.22 X 10(9) in buffy-coat-poor red blood cell preparations produced by centrifugation with the blood bag inverted, to 0.19 X 10(9) by perfusion through an Imugard filter, to 0.21 X 10(9) by the use of an IBM 2991 automated cell washer and to 0.13 X 10(9) with the use of frozen blood. The proportion of red cells recovered varied from 62% with the inverted-spin method to 85% with the use of frozen blood. Comparison of these data and the percentage of leukocytes removed, the shelf life of the product, the cost of supplies and the preparation time indicated that the use of sophisticated machinery, such as the IBM cell washer, or of glycerolization plus washing of frozen cells is not warranted for most patients. Instead, patients who have febrile nonhemolytic transfusion reactions should initially be treated with a leukocyte-poor red cell preparation produced by the inverted-spin method; only if such reactions recur should the blood bank be requested to provide filtered, washed or frozen red cells.     

Initial personal results of a technic of removing leukocytes by filtration on cotton fibers (Imugard Ig 500, Terumo)

The technical parameters of blood filtration through cotton Imugard IG 500 filters were evaluated. Sixty units of red cell concentrates were filtered. The mean value of the residual leukocytes indicated a leukocyte depletion greater than 98%, disregarding the unit age and the filtration temperature. The number of residual leukocytes was below 1 X 10(8) in 94% of the filtered units and less than 0.3 X 10(8) in 68%. The number of residual platelets was less than 1 X 10(10) in 92% of these units.     

Quantitative study of cellular and volumetric growth of magnocellular and laminar auditory nuclei in developing chick brainstem

Development of the second and third order auditory nuclei—nucleus magnoscellularis (NM) and nucleus laminaris (NL) respectively—was studied using Nissl stained serial sections from brain specimens between 8 day of incubation and posthatch day 1, at every two day interval. Reconstruction of these nuclei from three incubation ages showed progressive growth of both nuclei in a rostrocaudal direction. The volume, total neuron, dead cell and glial cell numbers were estimated using stereological quantitation methods. Both nuclei, while undergoing an overall gradual increase in volume up to 20 days registered a transient drop in volume; earlier for NM at 10 days and later for NL at 18 days. From day 20 the two nuclei showed accelerated growth in volume. The total neuron count rapidly declined up to 12 days with 43% loss of neurons in NM followed by a rise and later stabilization within a certain range. The NL, however, showed a continuous fall in neuron numbers throughout the incubation period with 20% cell loss by day 12 and an overall loss of 52%. Cell death in both nuclei was maximal at 16 days and spanned the entire period of incubation. Glia showed a biphasic increase with peak at 14 days for both NM and NL followed by a subsequent rise at day 20 for both nuclei. These data would help in planning further experimental studies of auditory manipulation.     

In vivo leukocyte labeling with intravenous ferumoxides/protamine sulfate complex and in vitro characterization for cellular magnetic resonance imaging

Cellular labeling with ferumoxides (Feridex IV) superparamagnetic iron oxide nanoparticles can be used to monitor cells in vivo by MRI. The objective of this study was to use histology and MRI to evaluate an in vivo, as opposed to in vitro, technique for labeling of mononuclear leukocytes as a means of tracking inflammatory processes in the brain. Long-Evans rats were intravenously injected with 20 mg/kg ferumoxides, ferumoxtran-10, or ferumoxytol with or without protamine sulfate. Leukocytes and splenocytes were evaluated by cell sorting and iron histochemistry or were implanted into the brain for MRI. Injection of ferumoxides/protamine sulfate complex IV resulted in iron labeling of leukocytes (ranging from 7.4 +/- 0.5% to 12.5 +/- 0.9% with average 9.2 +/- 0.8%) compared with ferumoxides (ranging from 3.9 +/- 0.4% to 6.3 +/- 0.5% with average 5.0 +/- 0.5%) or protamine sulfate alone (ranging from 0% to 0.9 +/- 0.7% with average 0.3 +/- 0.3%). Cell sorting analysis indicated that iron-labeled cells were enriched for cell types positive for the myelomonocytic marker (CD11b/c) and the B lymphocyte marker (CD45RA) and depleted in the T cell marker (CD3). Neither ferumoxtran-10 nor ferumoxytol with protamine sulfate labeled leukocytes. In vivo ferumoxides/protamine sulfate-loaded leukocytes and splenocytes were detected by MRI after intracerebral injection. Ferumoxides/protamine complex labeled CD45RA-positive and CD11b/c-positive leukocytes in vivo without immediate toxicity. The dose of feumoxides in this report is much higher than the approved human dose, so additional animal studies are required before this approach could be translated to the clinic. These results might provide useful information for monitoring leukocyte trafficking into the brain.     

Use of CD4 lymphocyte count to predict long-term survival free of AIDS after HIV infection.

OBJECTIVE--To estimate the probability of remaining free of AIDS for up to 25 years after infection with HIV by extrapolation of changes in CD4 lymphocyte count. DESIGN--Cohort study of subjects followed from time of HIV seroconversion until 1 January 1993. Creation of model by using extrapolated linear regression slopes of CD4 count to predict development of AIDS after 1993. SETTING--Regional haemophilia centre in teaching hospital. SUBJECTS--111 men with haemophilia infected with HIV during 1979-85. Median length of follow up 10.1 years, median number of CD4 counts 17. The model was not fitted for three men because only one CD4 measurement was available. MAIN OUTCOME MEASURES--Development of AIDS. INTERVENTIONS--From 1989 prophylaxis against candida and Pneumocystis carinii pneumonia and antiretroviral drugs when CD4 count fell below 200 x 10(6)/l. RESULTS--44 men developed AIDS up to 1 January 1993. When AIDS was defined as a CD4 count of 50 x 10(6)/l the model predicted that 25% (95% confidence interval 16% to 34%) would survive for 20 years after seroconversion and 18% (11% to 25%) for 25 years. Changing the CD4 count at which AIDS was assumed to occur did not alter the results. Younger patients had a higher chance of 20 year survival than older patients (32% (12% to 52%) for those aged < 15, 26% (14% to 38%) for those aged 15-29, and 15% (0% to 31%) for those aged > or = 30). CONCLUSIONS--These results suggest that even with currently available treatment up to a quarter of patients with HIV infection will survive for 20 years after seroconversion without developing AIDS.     

The recovery of mammalian cells treated with methyl methanesolfonate, nitrogen mustard or UV light. II. The importance of DNA repair prior to the initiation of S phase.

CHO cells were synchronized 2 G1 phase and treated with UV light or HN2. These treatments resulted in a dose-dependent reduction in the rate of DNA replication and cell survival. Holding UV-irradiated cells in G1 phase (in HU medium) for an additional 10 h prior to their release into S phase did not assist recovery as measured by either of these criteria. The survival of cells treated with HN2 was also not enhanced by this recovery period. However, following 2 X 10(-5) M HN2 the rate of DNA replication increased from 30% to 70% of the control level when the period in HU medium was extended to 14 h. The induction of cross-links following HN2 treatment of asynchronous cells was shown to be dose dependent. Subsequent incubation in fresh medium resulted in complete recovery within 20 h at concentrations of HN2 up to 10(-5) M, and at 2 X 10(-5) M HN2, 75% of the cross-links were removed at 14 h post treatment.     

Further investigations of red cell deformability with nickel mesh

Although the filtration method has been widely employed in red cell deformability studies, the structural irregularity of the pores of a Nuclepore polycarbonate membrane has always been a major problem. Anegawa, T. et al. (Clin. Hemorheol., 7, 1987) obtained a higher reproducibility with the filtration method using a newly designed thin metal film with pores engraved by the photofabrication technique. We further studied the pressure - flow rate relationship of red cell suspension employing this nickel mesh. The filtration of red cell suspensions through the nickel mesh was not influenced by leukocytes contamination or added leukocytes up to a leukocyte count of 250 cells/mm3 within an experimental limitation. On the other hand, the flow was greatly influenced by leukocytes contamination when the polycarbonate membrane was used. The nickel mesh was found to be useful in detecting major determinants of red cell deformability, such as cell geometry and internal cellular viscosity, and in detecting abnormalities of red cell deformability in a patient with microangiopathic hemolytic anemia. In conclusion, the present study clearly shows that the nickel mesh is preferable for investigating red cell deformability to the polycarbonate membrane from a quantitative point of view. This material should contribute to the physiologic and clinical investigation of red cell deformability.