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At least 19 recordsLinked to original sources
PubMed1998

Within-subject biological variation of reticulocytes and reticulocyte-derived parameters.

Automation of reticulocyte counting has decreased the analytical imprecision of this parameter. This has made it possible to use the number of reticulocytes and its derived parameters (reticulocyte maturity and reticulocyte cell indices) in new diagnostic and monitoring situations. For rational use of these parameters, it is important to have knowledge of their biological variability. The biological variability of reticulocytes and its derived parameters was studied in 13 healthy people during a period of 7 wk on 2 different instruments. The within-subject coefficient of variation for the reticulocyte count was about 11%, for the mean reticulocyte volume, mean reticulocyte haemoglobin content and mean reticulocyte haemoglobin concentration it was between 1 and 2%, whereas the coefficient of variations for the subpopulations of reticulocytes with different maturity varied depending on the method used for the measurements. The critical difference, that is the change in a result making it significantly different from the previous result, was about 35% for the reticulocyte count and 5-8% for the reticulocyte cell indices, making these indices excellent to follow changes in erythropoiesis. With a possible exception for the mean reticulocyte volume, the within-subject variation was small compared to the between-subject variation.

Adult↗
PubMed1994

Do the reticulocyte maturation fractions and bone marrow reticulocyte count further help the classification of anemias?

BACKGROUND: Reticulocyte count plays a major role in anemic evaluation. The conventional method done by the manual supravital staining cannot subclassify the group of less than 2% of corrected reticulocyte count. The newly-developed flow cytometer provides different maturation fractions by measuring its fluorescent intensity. The reticulocytes are believed to shift to the circulation from the bone marrow earlier in more severe anemia. Therefore, the purpose of this study is to evaluate the role of reticulocyte maturation fractions and bone marrow reticulocyte in anemia classification. METHODS: By using a fully automated counter, the roles of the reticulocyte with maturation and their shifting from bone marrow were evaluated in anemias. Different groups of subjects (243 in total) including aplastic, nutritional, and infiltrative anemias and anemia due to excess destruction and blood loss were studied. Each subject had bone marrow examination for morphologic diagnosis and reticulocyte evaluation. RESULTS: Both the absolute count and the maturation fractions of reticulocytes showed significant difference among marrow infiltration, aplastic anemia, and hemolytic anemia. Both the absolute reticulocyte count and less mature fractions were lowest in aplastic group. The marrow reticulocyte counts and shift ratio to circulating blood added little benefit in the classification of anemias. CONCLUSIONS: The automated reticulocyte count with maturation fractions helps classify anemias, particularly for those with low reticulocyte count by the manual method.

Adolescent↗
PubMed1985

Relationship of reticulocyte age to polychromasia, shift cells, and shift reticulocytes.

Polychromatophilic erythrocytes on Wright-stained blood smears represent young reticulocytes. Ratios of polychromatophilic cells to total reticulocyte counts have been used to estimate marrow response to erythropoietin stimulation. These ratios, however, require both accurate counts of polychromatophilic cells on Wright-stained blood smears and reticulocytes on supravitally stained blood smears. Data from this study indicated that reticulocytes of Heilmeyer groups I, II, and III best represent polychromatophilic cells. Group III reticulocytes, however, were found in normal circulation and were difficult to distinguish from group IV reticulocytes. Groups I and II were not found in normal circulation and were easily identified on routine reticulocyte preparations. The term "shift reticulocyte" is proposed for reticulocytes of groups I and II only. The present study suggests that the "shift reticulocyte count," expressed as percent of 100 reticulocytes, is a more useful indicator of marrow response to anemia than total reticulocyte counts.

Erythrocyte Aging↗
PubMed1994

Automated reticulocyte counting and measurement of reticulocyte cellular indices. Evaluation of the Miles H*3 blood analyzer.

This study evaluated reticulocyte counting and measurement of reticulocyte cellular indices with the Miles H*3 blood analyzer, a new instrument that combines the Technicon/Miles technology for blood cells counting with a staining technique allowing counting of reticulocytes, quantification of staining intensity and measurement of reticulocyte cellular indices. Reticulocyte counts obtained with the Miles H*3 analyzer were compared with those obtained by manual counting, flow cytometry (thiazole orange method) and by the Sysmex R-3000 (Baxter Diagnostics) reticulocyte analyzer. Reticulocyte counting with the Miles H*3 showed excellent precision, and linearity in the range tested (1.1-49% and 1-72% reticulocytes, respectively, with two different protocols) with no significant carryover. Reticulocyte counts were stable after storing blood samples for 72 hours at 4 degrees C. Comparison of the four different methods, showed an acceptable intraclass correlation between Miles H*3 and Sysmex R-3000 (intraclass correlation coefficient, [ri] = .952), Miles H*3 and flow cytometry (ri = .922), and Sysmex R-3000 and flow cytometry (ri = .938). There was no satisfactory correlation between any of the three automated methods and the values obtained with manual counting of reticulocytes (ri = .538-.755), consistent with the well known imprecision of the manual technique. For a group of normal pediatric subjects, age 1-10, we obtained the following values (+/- SD) of reticulocyte indices: mean corpuscular volume 97.6 +/- 4.7 fL; cell hemoglobin concentration mean 28.2 +/- 1.4 g/dL; cell hemoglobin content 26.7 +/- 1.6 pg. We determined the direct cost, including depreciation, of the manual and instrumental methods. Cost/test varied from $1.61 for manual method to $6.03 for the Sysmex R-3000. Cost/test for flow cytometry and Miles H*3 were $3.34 and $3.49, respectively.

Child↗
PubMed1992

[The correlation between hematopoietic status of the bone marrow and peripheral or marrow reticulocyte classification by using the automated reticulocyte analyzer Sysmex R-3000].

In this study peripheral and marrow reticulocytes were counted by using the automated reticulocyte analyzer Sysmex R-3000 with the quick and accurate function of reticulocyte classification dependent on reticulocyte maturation. The correlation of reticulocyte count of the R-3000 to that of visual reticulocyte counting method was r = 0.926, y = 0.88x + 0.305 and r = 0.933, y = 1.32x + 0.328 for peripheral blood and bone marrow, respectively. The hematopoietic status of the bone marrow was reflected in peripheral reticulocytes better than in leukocytes or platelets. Moreover, at recovery stage from bone marrow suppression after chemotherapy, the ratio of immature type (HFR fraction) in peripheral reticulocytes increased to precede in several days increasing total reticulocytes. The relative reticulocyte counts in bone marrow was about 3 times higher than peripheral blood to be drawn at the same time higher and the patients suffering from megaloblastic anemia, MDS or DIC tended to have a much higher reticulocyte count in bone marrow than in peripheral blood.

Aged↗
PubMed1997

Evaluation of the reticulocyte count portion of technicon H*3 blood analyzer: lowering the test expense by reducing the reticulocyte reagent.

Automated reticulocyte counting has become an essential instrument of the hematology laboratory. This automatic technique has lead to diminishing labour tasks and to significant improvements in accuracy and precision compared with the manual microscopic methods. In any event, it adds a considerable expense to the laboratory budget. Here, we report the modified method of applying the new mixture of 1 microL of whole blood with 1 mL of reticulocyte reagent, which we evaluated for its accuracy and precision, instead of using the mixture of 3 microL of whole blood with 3 mL of reticulocyte reagent recommended by the company. We demonstrated the accepted accurate and precise results of percentage and absolute number of retculocyte count, low-stained reticulocyte count and its corpuscular indices; the mean reticulocyte corpuscular volume (MCVr), mean reticulocyte corpuscular hemoglobin concentration (CHCMr), and mean reticulocyte hemoglobin content (CHr). These suggested that, for every red cell assessed, the number, the cell volume, hemoglobin content and concentration are accurately and precisely measured by the modified method while the sub-populations of reticulocyte count and distribution width of reticulocyte indices are variable. In conclusion, our results provided the information that 1) the modified method can be used as a routine test and it provides accurate and precise results; 2) with the modified method, two-thirds of the expense spent for reticulocyte reagent can be saved; 3) it should not be used for research purposes.

Indicators and Reagents↗
PubMed1990

Reticulocytes II: Reexamination of the in vivo survival of stress reticulocytes.

Very young reticulocytes are released into the circulation in response to the stress of anemia. These stress reticulocytes have shortened in vivo survival when transfused into normal recipients, and are generally considered to be abnormal because they have skipped a terminal cell division. We reevaluated one aspect of their abnormality: that of in vivo survival. Using methodology that accounted for all cells transfused, in vivo survival of both normal and stress reticulocytes was investigated in both normal and anemic recipients. The experiments demonstrate that: (1) survival of reticulocytes is normal only when normal reticulocytes are injected into nonanemic animals; (2) intrinsic properties of stress reticulocytes lead to their immediate removal from the circulation by normal recipients to a significantly greater extent than by anemic recipients; and (3) both stress and normal reticulocytes are removed at an accelerated rate over time by anemic recipients. Taken together, the data indicate that in the course of becoming anemic, an adaptation occurs that allows cells produced during anemia to circulate considerably longer in anemic animals than they could in normal nonanemic animals. Other studies disclosed that increased reticulocyte survival in anemic animals could not be attributed to reticuloendothelial overload, but is induced by adaptation of the spleen, decreasing its removal of stress reticulocytes.

Anemia↗
PubMed1990

A new method for isolation of reticulocytes: positive selection of human reticulocytes by immunomagnetic separation.

A method for isolating pure reticulocytes from leukocyte-depleted blood of normal persons is presented. The separation was achieved using an immunomagnetic technique. A monoclonal mouse antibody against human transferrin receptor was bound to magnetic beads conjugated with sheep antimouse antibody. The recovery of reticulocytes from peripheral blood was 15% to 42%. Blood used for isolation of reticulocytes could be stored for 4 days at 22 degrees C without altering the yield of reticulocytes. At 37 degrees C incubation, the reticulocytes matured rapidly and the transferrin receptor was found to have a half-life of 16 hours. The activity of several enzymes and the amount of creatine and hemoglobin A1C were measured both in the reticulocytes and peripheral blood. Of the enzymes, porphobilinogen deaminase had the best discriminatory power with a ratio of 8.8 between reticulocytes and peripheral red blood cells. The ratio for creatine was 16.7. The ability to isolate pure human reticulocytes, released after normal erythropoiesis, will offer new possibilities in the study of these cells.

Adult↗
PubMed1993

Flow cytometric reticulocyte analysis and the reticulocyte maturity index.

Reticulocyte analysis has evolved to one of the accepted and routinely practiced clinical applications of flow cytometry technology. Similar to CD4 measurements, FCM technology has contributed to documented improvements in reticulocyte counting precision over previous microscope-based techniques. The ability to FCM instruments to quantitate fluorescence intensity has been utilized to derive a parameter of reticulocyte maturity, which we have termed the reticulocyte maturity index. The FCM-derived RMI parameter offers an additional perspective to assess the erythropoietic response in anemic patients over reticulocyte counting alone and provides further insight into the differential diagnosis of anemia. Clinical utility of the RMI has been reported in monitoring expensive, new-technology therapies, such as bone marrow transplantation and erythropoietin therapy. FCM reticulocyte analysis is still not fully mature, but is in a state of continued evolution. Needs exist for (i) improved software for data analysis, (ii) newer automation techniques to improve interlaboratory correlations, and (iii) further validation and refinement of the reticulocyte maturity index parameter.

Anemia↗
PubMed1975

The maturation of reticulocytes. I. Following introduction of reticulocytes into polycythemic and normocythemic animals.

Investigations were conducted on the life-span of "stress" reticulocytes and the fate of the early denucleated large-sized reticulocytes in circulating blood. Reticulocyte disappearance was examined after reticulocyte introduction into the vein and into the peritoneal cavity of polycythemic and normocythemic animals. The results indicated that these introduced reticulocytes matured to red cells by about 36 hours after injection under both the polycythemic and normocytehmic conditions. The large-sized reticulocytes disappeared by about 4 to 12 hours after introduction. The maturation of reticulocytes was largely arrested when the cells were introduced into the peritoneal cavity.

Animals↗
PubMed1989

Flow cytometric reticulocyte quantification using thiazole orange provides clinically useful reticulocyte maturity index.

Flow cytometric reticulocyte quantification with thiazole orange has been reported to be of potential utility in a clinical hematology laboratory. We have instituted this technique into routine clinical testing for 18 months and we describe this experience. Flow cytometric analysis provided not only reproducible, cost-effective reticulocyte quantification, but a quantitative reticulocyte maturity index proportional to the amount of RNA in the reticulocytes. The reticulocyte maturity index measurement represents an independent parameter of erythropoiesis, which provided clinically valuable information regarding bone marrow engraftment in patients following autologous bone marrow transplantation. The findings of this study demonstrate the clinical utility of thiazole orange reticulocyte analysis and indicate the diagnostic importance of the reticulocyte maturity index measurement in the evaluation of erythropoietic activity.

Benzothiazoles↗
PubMed1997

Automated reticulocyte counting: evaluation of the Coulter STKS Haematology Analyser reticulocyte counting function.

This study evaluated reticulocyte counting with the automated reticulocyte function of the Coulter STKS Haematology Analyser. This is an upgrade option for Coulter STKS and MAXIM haematology analysers. Reticulocyte counts obtained with the automated reticulocyte counting function were compared with those obtained by visual counting. Reticulocyte counting with both methods gave excellent comparability with a correlation coefficient of 0.98. Results were consistent with the well documented imprecision of the manual method with a coefficient of variation (CV) of 16-22%. In contrast, the automated reticulocyte counting function was more precise with a CV of 12.3%. In both cases, counts were stable after storage for 24 h at room temperature and 4 degrees C. Our results suggest that the use of this upgrade will be beneficial for many laboratories.

Autoanalysis↗
PubMed1997

Clinical significance of immature reticulocyte fraction determined by automated reticulocyte counting.

The Sysmex R-3000 (TOA Medical Electronics, Kobe, Japan) evaluates maturation of reticulocytes by quantitating the fraction of reticulocytes within low-, middle-, and high-fluorescence intensity regions. We defined the immature reticulocyte fraction (IRF) as the sum of the fraction of high-fluorescence intensity regions plus the fraction of middle-fluorescence intensity regions. Then, we studied the clinical significance of IRF in the evaluation of anemia by comparing the IRF with the absolute reticulocyte count (ARC) and with the reticulocyte production index (RPI) and by reviewing pertinent clinical information about the patients. In the study, 132 specimens from 102 patients undergoing evaluation of anemia were analyzed. By using simple regression analysis, our results showed that the IRF has a weak but significantly positive correlation with ARC and with RPI, indicating that IRF is an additional useful parameter to evaluate the erythropoietic activity in anemia. Interpretation by integrating IRF and reticulocyte enumeration (ARC and RPI) provided useful information for further subclassification of anemia. Increased IRF (IRF > or = 0.23) and increased ARC generally indicated an adequate erythroid response to anemia. All but three specimens with an IRF less than 0.23 showed an RPI of 2 or less. These specimens were from patients with underlying diseases known to lead to decreased erythropoietic activity, predominantly chronic renal insufficiency. Specimens with a subnormal or normal ARC (with a corresponding RPI < or = 2) but with an IRF of more than 0.23 were from patients with various underlying conditions, including acute infection, iron deficiency anemia, human immunodeficiency virus infection, sickle disease with crisis, pregnancy, and myelodysplastic syndrome. Our results indicate that an IRF of 0.23 or less in patients with anemia reflects bone marrow that is nonresponsive or underresponsive to the anemia. Patients with an increased IRF (IRF > or = 0.23) may require further examination to clarify the cause of the anemia.

Adult↗
PubMed1992

Uptake of transferrin-bound and nontransferrin-bound iron by reticulocytes from the Belgrade laboratory rat: comparison with Wistar rat transferrin and reticulocytes.

The mechanism underlying the impaired uptake of iron from transferrin by reticulocytes from the Belgrade laboratory rat was investigated using 125I- and 59Fe-labeled transferrin isolated from homozygous Belgrade rats and from Wistar rats, nontransferrin-bound Fe(II) in an isotonic sucrose solution, and reticulocytes from Belgrade and Wistar rats. The Belgrade rat transferrin had the same molecular weight and net charge as Wistar rat transferrin, donated iron equally well to both types of reticulocytes, and competed equally for transferrin binding sites on the cells. Hence, the defect in iron uptake by Belgrade rat reticulocytes could not be attributed to an abnormality of the transferrin molecule. The rate of uptake of Fe(II) from sucrose into the cytosolic and stromal fractions of Belgrade rat reticulocytes was only about 35% as great as that by Wistar rat reticulocytes. With both types of cells, the uptake process was saturable, suggesting the presence of a carrier-mediated process. It was therefore concluded that the defect in iron uptake by Belgrade rat erythroid cells is probably the consequence of a deficiency in a membrane carrier for iron.

Animals↗
PubMed1982

Pig reticulocytes. IV. In vitro maturation of naturally occurring reticulocytes with permeability loss to glucose.

Naturally occurring reticulocytes of week old piglets were used to characterize the maturation process under in vitro conditions. When the reticulocytes were suspended in tissue culture medium fortified with metabolic substrates, nearly all cells were viable after 24 hours incubation and usually more than 85% of the initial cell population survived after an 80 hour period. In cells maintained as long as a week in incubation, an adequate level of total adenine nucleotide with a large accumulation of IMP was found. In most cases, reticulocytes lose their reticular materials within two days and assume normal erythrocyte configuration. Concomitant with the morphological change, the cell volume decreases toward normal erythrocyte size, the extent of which can be accounted for by the intracellular loss of salt and accompanying water. As in the in vivo reticulocyte maturation process, reticulocytes undergoing in vitro maturation lose their membrane permeability to glucose. These findings suggest that the process of reticulocyte maturation occurring in cell culture approaches that which naturally occurs in vivo. Thus, these cells may be used to delineate the mechanism of the loss of membrane transport of glucose which normally occurs in the adult pig cells.

2,3-Diphosphoglycerate↗
PubMed1976

Pig reticulocytes: II. Characterization of density-fractionated maturing reticulocytes.

A simple centrifugation technique initially developed for fractionation of human red cells in their own plasma has been found to be readily applicable to the separation of reticulocytes normally appearing in the pig soon after birth as well as to those induced in the adult pig by phenylhydrazine administration. The density of the naturally occurring reticulocytes, maximally amounting to 10-15% of total cells derived from a 7-day-old pig, varied from 1.073 to 1.101, in contrast to the mature cells, presumed to be the fetal cell type, whose density ranged in a narrower limit, from 1.101 to 1.106. In adult animals, the reticulocytosis amounting to more than 70% takes place in response to daily administration of phenylhydrazine for 7 days. The density of these reticulocytes varied widely from 1.068 to 1.094; in contrast, the density of the mature adult red cells ranged from 1.095 to 1.106. Among various physiological parameters examined, a marked decrease in cell size, cell water content, RNA, Na+ -K+ -ATPase, and Ca2+ -ATPase activities was observed in the course of reticulocyte maturation in vivo in the adult animal. All these physiological parameters were found to undergo a similar reduction from the top to the bottom fractions of the reticulocytes separated according to their density, suggesting that the separation technique employed here represents separation of reticulocytes according to their age.

Acetylcholinesterase↗
PubMed1990

Occurrence of lipoxygenase products in membranes of rabbit reticulocytes. Evidence for a role of the reticulocyte lipoxygenase in the maturation of red cells.

A lipoxygenase has been found in the reticulocytes of all mammalian species tested so far (rabbit, rat, mouse, monkey, and humans); evidence from in vitro studies suggests that the lipid-peroxidizing effects of this enzyme could render the mitochondrion and other intracellular organelles prone to the proteolytic degradation which is a natural step in development of the reticulocyte to the mature red cell. In this study we sought evidence of an active lipoxygenase in vivo. A bleeding anemia was induced in rabbits, and in the course of the subsequent reticulocytosis the red cell membranes were examined for the presence of the characteristic lipoxygenase products of linoleic and arachidonic acids. Erythrocyte membranes from control collections contained only small amounts of hydroxy fatty acids (0.03-0.08% of the polyenoic fatty acids). In contrast, reticulocyte-enriched red cells contained up to 3.3% of the polyenoic acids as hydroxylated derivatives. The main hydroxy fatty acid in reticulocyte membranes was identified as 13-L(S)-hydroxy-9Z,11E-octadecadienoic acid. Small amounts of other hydroxy derivatives including 15-hydroxy-5,8,11,13-(Z,Z,Z,E)eicosatetraenoic acid were also detected. These products appeared about 3 days after development of reticulocytosis. The precise structures of the hydroxylated polyenoic fatty acids and the time course of their appearance strongly suggest that their formation is due to the intracellular action of the cell-specific reticulocyte lipoxygenase. These findings are the first evidence for an activity of this enzyme in vivo, and the results support the hypothesis that enzymic peroxidation of reticulocyte intracellular membranes is a step in preparation of the intracellular organelles for proteolytic degradation.

Animals↗
PubMed1985

Maturation of rabbit reticulocytes: susceptibility of mitochondria to ATP-dependent proteolysis is determined by the maturational state of reticulocyte.

A simple procedure is described to separate reticulocytes of different maturity in high yield. It is shown that exhaustion of supply of mitochondria susceptible to degradation by the lipoxygenase-ATP-dependent proteolysis system limits the extent of breakdown of mitochondria during in vitro maturation. The susceptibility of mitochondria depends on the maturity of the reticulocytes. Incubation in the presence of calcium ions and calcium ionophore leads to full susceptibility of mitochondria in immature reticulocytes but has no effect on those in mature reticulocytes which are already fully susceptible to degradation. Conditions which lead to rapid degradation of mitochondria do not affect the behaviour of the reticulocyte count. There appears to be no obligatory connection between the breakdown of mitochondria and of ribosomes.

Adenosine Triphosphate↗