[Risk factors for delayed bleeding after intestinal polypectomy in children]. / å„¿ç«¥è‚ æ¯è‚‰åˆ‡é™¤æœ¯åŽè¿Ÿå‘æ€§å‡ºè¡€çš„å±é™©å› ç´ åˆ†æž.

OBJECTIVES: To investigate the clinical characteristics and risk factors of delayed bleeding after intestinal polypectomy in children, and to provide a theoretical basis for clinical surgical intervention of intestinal polyps. METHODS: A retrospective analysis was conducted on the clinical data of 2 456 children with intestinal polyps who underwent endoscopic high-frequency electrocoagulation loop resection in the Endoscopy Center of Children's Hospital Affiliated to Zhengzhou University from January 2014 to December 2021. According to the presence or absence of delayed bleeding after surgery, they were divided into bleeding group with 79 children and non-bleeding group with 2 377 children. A multivariate logistic regression analysis was used to investigate the risk factors for delayed bleeding. The receiver operating characteristic (ROC) curve was used to investigate the value of various indicators in predicting delayed bleeding. RESULTS: Of all 2 456 children, 79 (3.22%) experienced delayed bleeding, among whom 5 children with severe delayed bleeding underwent emergency colonoscopy for hemostasis and 74 received conservative treatment, and successful hemostasis was achieved for all children. There were significant differences between the bleeding and non-bleeding groups in age, body mass index, constipation rate, location of lesion, time of endoscopic procedure, resection method (P<0.05). Children with a diameter of polyps of 6-10 mm and >20 mm were more likely to develop delayed bleeding after resection (P<0.05). The multivariate logistic regression analysis showed that endoscopic operation time, polyp diameter, and resection method were significantly associated with delayed bleeding (P<0.05). The ROC curve analysis showed that the endoscopic operation time, polyp diameter, and resection method had a good value in predicting delayed bleeding after intestinal polypectomy, with an area under the ROC curve of 0.706, 0.688, and 0.627, respectively. CONCLUSIONS: Endoscopic high-frequency electrocoagulation loop resection has a lower incidence of delayed bleeding in children with intestinal polyps, and the endoscopic operation time, polyp diameter, and resection method are closely associated with the occurrence of postoperative delayed bleeding.

The impact of erythroblast enucleation efficiency on the severity of anemia in patients with myelodysplastic syndrome.

Anemia is the most common manifestation in myelodysplastic syndrome (MDS) patients, but the cause of ineffective hematopoiesis is not fully understood. Enucleation is an important event in the maturation process of erythroblasts. According to a series of morphological phenotypes of the pathological development of MDS erythroblasts, we speculate that there may be enucleation disorders. To verify this hypothesis, we cultured MDS bone marrow CD34+ cells in vitro and induced erythroblast development. The results showed that erythroblast enucleation in MDS was significantly lower than that in the normal group, and the rate of enucleation was positively correlated with hemoglobin concentration. Risk stratification of MDS was performed to further analyze the differences in enucleation among the normal group, low-middle risk group and high-risk group. The results showed that the enucleation rate of the high risk group was higher than that of the low-middle risk group but still lower than that of the normal group. Moreover, the expression of pERK and pAKT in MDS erythroblasts in the high risk group was higher than that in the normal group, while the expression of pERK and pAKT in the low-middle risk group was lower than that in the normal group. Furthermore, the enucleation of MDS was positively correlated with the phosphorylation degree of ERK and AKT. In conclusion, this study reveals that the enucleation of erythroblasts is one of the possible causes of anemia in MDS. Video Abstract.

Stage-specific dual function: EZH2 regulates human erythropoiesis by eliciting histone and non-histone methylation.

Enhancer of zeste homolog 2 (EZH2) is the lysine methyltransferase of polycomb repressive complex 2 (PRC2) that catalyzes H3K27 tri-methylation. Aberrant expression and loss-of-function mutations of EZH2 have been demonstrated to be tightly associated with the pathogenesis of various myeloid malignancies characterized by ineffective erythropoiesis, such as myelodysplastic syndrome (MDS). However, the function and mechanism of EZH2 in human erythropoiesis still remains largely unknown. Here, we demonstrated that EZH2 regulates human erythropoiesis in a stage-specific, dual-function manner by catalyzing histone and non-histone methylation. During the early erythropoiesis, EZH2 deficiency caused cell cycle arrest in the G1 phase, which impaired cell growth and differentiation. Chromatin immunoprecipitation sequencing and RNA sequencing discovered that EZH2 knockdown caused a reduction of H3K27me3 and upregulation of cell cycle proteindependent kinase inhibitors. In contrast, EZH2 deficiency led to the generation of abnormal nuclear cells and impaired enucleation during the terminal erythropoiesis. Interestingly, EZH2 deficiency downregulated the methylation of HSP70 by directly interacting with HSP70. RNA-sequencing analysis revealed that the expression of AURKB was significantly downregulated in response to EZH2 deficiency. Furthermore, treatment with an AURKB inhibitor and small hairpin RNAmediated AURKB knockdown also led to nuclear malformation and decreased enucleation efficiency. These findings strongly suggest that EZH2 regulates terminal erythropoiesis through a HSP70 methylation-AURKB axis. Our findings have implications for improved understanding of ineffective erythropoiesis with EZH2 dysfunction.

Hot Water Extraction of Antioxidants from Tea Leaves-Optimization of Brewing Conditions for Preparing Antioxidant-Rich Tea Drinks.

There are billions of tea drinkers around the world. However, the optimized tea-brewing temperature and time conditions for achieving a higher concentration of antioxidants in tea drinks have not been thoroughly studied. Finding out the optimized brewing conditions can benefit tea drinkers significantly. In this work, we have studied ten antioxidants from seven different popular green, Oolong, black, and scented teas using hot water extraction followed by HPLC analysis. The antioxidant yield was evaluated at 25-100 °C with 5 to 720 min of brewing time. Our results show that the extraction efficiency was enhanced by increasing the water temperature and the highest yield of antioxidants was achieved at 100 °C. The antioxidant yield increased with prolonged brewing time. However, the degradation of antioxidants occurred when tea leaves were extracted for 120 to 720 min. Caffeine was found in all seven tea samples. At 100 °C, the caffein concentration in the tea extract ranged from 7.04 to 20.4 mg/g in Rizhao green tea. Longjing green tea contained the highest concentration of antioxidants (88 mg/g) in the 100 °C extract. Epigallocatechin and caffeine were the most abundant compounds found in all tea samples studied, ranging from 4.77 to 26.88 mg/g. The antioxidant yield was enhanced by increasing the extraction time to up to 60-120 min for all ten compounds studied.

DNA methylation status of DNAJA4 is essential for human erythropoiesis.

Aims: To investigate DNA methylation patterns in early and terminal stages of erythropoiesis, and to explore the function of differentially methylated genes in erythropoiesis and erythroid disorders. Materials & methods: Differential analysis of DNA methylation and gene expression during erythropoiesis, as well as weighted gene coexpression network analysis of acute myeloid leukemia was performed. Results: We identified four candidate genes that possessed differential methylation in the promoter regions. DNAJA4 affected proliferation, apoptosis and enucleation during terminal erythropoiesis and was associated with the prognosis of acute myeloid leukemia. DNAJA4 was specifically highly expressed in erythroleukemia and is associated with DNA methylation. Conclusion: DNAJA4 plays a crucial role for erythropoiesis and is regulated via DNA methylation. Dysregulation of DNAJA4 expression is associated with erythroid disorders.

Research hotspot and trend analysis in the diagnosis of inflammatory bowel disease: A machine learning bibliometric analysis from 2012 to 2021.

Aims: This study aimed to conduct a bibliometric analysis of the relevant literature on the diagnosis of inflammatory bowel disease (IBD), and show its current status, hot spots, and development trends. Methods: The literature on IBD diagnosis was acquired from the Science Citation Index Expanded of the Web of Science Core Collection. Co-occurrence and cooperation relationship analysis of authors, institutions, countries, journals, references, and keywords in the literature were carried out through CiteSpace software and the Online Analysis platform of Literature Metrology. At the same time, the relevant knowledge maps were drawn, and the keywords cluster analysis and emergence analysis were performed. Results: 14,742 related articles were included, showing that the number of articles in this field has increased in recent years. The results showed that PEYRIN-BIROULET L from the University Hospital of Nancy-Brabois was the author with the most cumulative number of articles. The institution with the most articles was Mayo Clin, and the United States was far ahead in the article output and had a dominant role. Keywords analysis showed that there was a total of 818 keywords, which were mainly focused on the research of related diseases caused or coexisted by IBD, such as colorectal cancer and autoimmune diseases, and the diagnosis and treatment methods of IBD. Emerging analysis showed that future research hotspots and trends might be the treatment of IBD and precision medicine. Conclusion: This research was the first bibliometric analysis of publications in the field of IBD diagnosis using visualization software and data information mining, and obtained the current status, hotspots, and development of this field. The future research hotspot might be the precision medicine of IBD, and the mechanism needed to be explored in depth to provide a theoretical basis for its clinical application.

An Injectable Hydrogel to Modulate T Cells for Cancer Immunotherapy.

T cell exhaustion caused by mitochondrial dysfunction is the major obstacle of T cells-based cancer immunotherapy. Besides exhausted T cells, the insufficient major histocompatibility complex class I (MHC I) on tumor cells leads to inefficient T cell recognition of tumor cells, compromising therapeutic efficacy. Therapeutic platform to regulate T cell exhaustion and MHC I expression for boosting T cells-based cancer immunotherapy has not been realized up to date. Herein, an injectable hydrogel is designed to simultaneously tune T cell exhaustion and MHC I expression for amplified cancer immunotherapy. The hydrogel is in situ constructed in tumor site by utilizing oxidized sodium alginate-modified tumor cell membrane vesicle (O-TMV) as a gelator, where axitinib is encapsulated in the lipid bilayer of O-TMV while 4-1BB antibody and proprotein convertase subtilisin/kexin type 9 inhibitor PF-06446846 nanoparticles are present in the cavities of hydrogel. After immune response trigged by O-TMV antigen, the 4-1BB antibody-promoted T cell mitochondrial biogenesis and the axitinib-lowered hypoxia synergistically reverse T cell exhaustion while the PF-06446846-amplified MHC I expression facilitates T cell recognition of tumor cells, demonstrating a powerful immunotherapeutic efficacy. This strategy on reprograming T cell exhaustion and improving T cell potency offers new concept for T cells-based cancer immunotherapy.

A carrier-free photodynamic nanodrug to enable regulation of dendritic cells for boosting cancer immunotherapy.

Immune response is initiated by dendritic cells (DCs), where the cross-presentation of antigens by DCs determines the activating of cytotoxic T cells. However, the efficacy of DCs-initiated immune response is governed by multiple (cascade) steps of immunogenic cell death (ICD), recruitment of DCs, and cross-presentation of DCs. It is urgent but challenging to achieve a platform for simultaneously regulating these multiple steps, amplifying the immune response against tumors. Herein, we reported a photodynamic nanodrug enabling simultaneous regulation of these multiple steps for realizing powerful immune response. The nanodrug was designed by the co-assembling of chlorin e6 (Ce6), celecoxib and 6-thio-2'-deoxyguanosine (6-thio-dG). In our nanodrug, Ce6 enables induction of ICD, while celecoxib down-regulates the prostaglandin E2 (PGE2) for promoting recruitment of DCs enabled by chemokine CCL5 produced from natural killer (NK) cells. Moreover, 6-thio-dG triggers DNA damages in the tumor cells, which in turn activates STING/interferon I pathway for enhancing the cross-presentation ability of DCs. Therefore, an amplified immune therapeutic effect against tumors is achieved, thanks to the simultaneous regulation of these multiple steps. The nanodrug effectively inhibits tumor growth and postoperative recurrence, demonstrating a new approach for boosting immune response initiated by DCs in cancer therapy. STATEMENT OF SIGNIFICANCE: The dendritic cells (DCs)-initiated immune response against tumors is dominated by multiple (cascade) steps including the process of (I) immunogenic cell death (ICD), (II) recruitment of DCs, and (III) cross-presentation of antigens by DCs. Based on this, it is urgent to design a nanoplatform enabling simultaneous regulation of these multiple steps for achieving a potent therapeutic efficacy. A carrier-free photodynamic nanodrug, engineered by a co-assembling approach, was designed to regulate DCs for realizing a powerful DCs-initiated immune response against tumors, thanks to the simultaneous regulation of the above multiple steps. Our nanodrug demonstrated a boosted immune response against tumors, powerfully suppressing primary/abscopal tumor growth and postoperative recurrence, which offers a conceptually innovative strategy for amplifying immunity against tumors.

Determination and Correlation of Solubility of Metformin Hydrochloride in Aqueous Binary Solvents from 283.15 to 323.15 K.

Metformin hydrochloride (MET·HCl) is one of the most widely used oral hypoglycemic drugs in the world. In addition to hypoglycemic effects, MET·HCl also has anti-inflammatory, anti-tumor, anti-aging, and other effects, showing good efficacy and safety of single and combined treatment. The solubility of MET·HCl in water, water + N,N-dimethylformamide, water + acetonitrile, and water + n-propanol was measured by the gravimetric method under atmospheric pressure at temperatures ranging from 283.15 to 323.15 K. The solubility of MET·HCl has a positive correlation with temperature and water content. The experimental solubility data in binary solvents was correlated by the modified Apelblat model, CNIBS/R-K model, Apelblat-Jouyban-Acree model, and λh model. By comparing the average ARD % values of the four models, it is found that the modified Apelblat model (ARD % = 1.26) provides better correlation. Hansen solubility parameters and apparent thermodynamic parameters were calculated to analyze the solubility behavior, indicating that the dissolution process is endothermic and entropically favorable.

Subcritical Water Extraction of Natural Products.

Subcritical water refers to high-temperature and high-pressure water. A unique and useful characteristic of subcritical water is that its polarity can be dramatically decreased with increasing temperature. Therefore, subcritical water can behave similar to methanol or ethanol. This makes subcritical water a green extraction fluid used for a variety of organic species. This review focuses on the subcritical water extraction (SBWE) of natural products. The extracted materials include medicinal and seasoning herbs, vegetables, fruits, food by-products, algae, shrubs, tea leaves, grains, and seeds. A wide range of natural products such as alkaloids, carbohydrates, essential oil, flavonoids, glycosides, lignans, organic acids, polyphenolics, quinones, steroids, and terpenes have been extracted using subcritical water. Various SBWE systems and their advantages and drawbacks have also been discussed in this review. In addition, we have reviewed co-solvents including ethanol, methanol, salts, and ionic liquids used to assist SBWE. Other extraction techniques such as microwave and sonication combined with SBWE are also covered in this review. It is very clear that temperature has the most significant effect on SBWE efficiency, and thus, it can be optimized. The optimal temperature ranges from 130 to 240 °C for extracting the natural products mentioned above. This review can help readers learn more about the SBWE technology, especially for readers with an interest in the field of green extraction of natural products. The major advantage of SBWE of natural products is that water is nontoxic, and therefore, it is more suitable for the extraction of herbs, vegetables, and fruits. Another advantage is that no liquid waste disposal is required after SBWE. Compared with organic solvents, subcritical water not only has advantages in ecology, economy, and safety, but also its density, ion product, and dielectric constant can be adjusted by temperature. These tunable properties allow subcritical water to carry out class selective extractions such as extracting polar compounds at lower temperatures and less polar ingredients at higher temperatures. SBWE can mimic the traditional herbal decoction for preparing herbal medication and with higher extraction efficiency. Since SBWE employs high-temperature and high-pressure, great caution is needed for safe operation. Another challenge for application of SBWE is potential organic degradation under high temperature conditions. We highly recommend conducting analyte stability checks when carrying out SBWE. For analytes with poor SBWE efficiency, a small number of organic modifiers such as ethanol, surfactants, or ionic liquids may be added.

Electrochemiluminescence ultrasensitive immunoassay for carbohydrate antigen 125 based on AgInS2/ZnS nanocrystals.

We developed a near-infrared (NIR) electrochemiluminescence (ECL) immunosensor for sensitively and selectively determining carbohydrate antigen 125 (CA125) with toxic-element-free and environmental-friendly AgInS2/ZnS nanocrystals (NCs) as tags. The core/shell-structured AgInS2/ZnS NCs not only can be conveniently prepared via an aqueous synthetic procedure, but also has high photoluminescence quantum yield (PLQY) of up to 61.7%, highly monodispersed, water-soluble, and desired biological compatibility. As AgInS2/ZnS NCs can be oxidized via electrochemically injecting holes into their valence band at + 0.84 V, both the monodispersed AgInS2/ZnS NCs in solution and the surface-confined AgInS2/ZnS NCs immobilized in sandwich-typed immuno-complexes with CA125 as analyte can exhibit efficient oxidative-reduction ECL around 695 nm under physiological conditions with the presence of tri-n-propylamine (TPrA). The ECL intensity from the AgInS2/ZnS NCs immobilized in sandwich-typed immuno-complexes increases linearly and selectively with an increased concentration of CA125 from 5 × 10-6 to 5 × 10-3 U/mL, and limit of detection (LOD) was 1 × 10-6 U/mL (S/N = 3). This reliable platform can provide an effective detection method in the early diagnosis and treatment of ovarian cancer.

4.1B suppresses cancer cell proliferation by binding to EGFR P13 region of intracellular juxtamembrane segment.

BACKGROUND: Gastric cancer (GC) has high incidence and mortality worldwide. However, the underlying mechanisms that regulate gastric carcinogenesis are largely undefined. 4.1B is an adaptor protein found at the interface of membrane and the cytoskeleton. Previous studies demonstrated that 4.1B serves as tumor suppressor. RESULTS: We showed that 4.1B expression was decreased or lost in most GC patients. The expression pattern of it was tightly correlated with tumor size, TNM stage and overall survival (OS). We further showed that 4.1B inhibited the proliferation of two GC cell lines, MGC-803 and MKN-45, by impeding the EGFR/MAPK/ERK1/2 and PI3K/AKT pathways. A similar phenotype was also observed in immortalized mouse embryonic fibroblasts (MEF) derived from wild type (WT) and 4.1B knock-out (BKO) mice. Additionally, immunofluorescence (IF) staining and Co-IP showed that protein 4.1B bound to EGFR. Furthermore, the FERM domain of 4.1B interacted with EGFR through the initial 13 amino acids (P13) of the intracellular juxtamembrane (JM) segment of EGFR. The binding of 4.1B to EGFR inhibited dimerization and autophosphorylation of EGFR. CONCLUSION: Our present work revealed that 4.1B plays important regulatory roles in the proliferation of GC cells by binding to EGFR and inhibiting EGFR function through an EGFR/MAPK/ERK1/2 pathway. Our results provide novel insight into the mechanism of the development and progression of GC.

Severely impaired terminal erythroid differentiation as an independent prognostic marker in myelodysplastic syndromes.

Anemia is the defining feature in most patients with myelodysplastic syndromes (MDS), yet defects in erythropoiesis have not been well characterized. We examined freshly obtained bone marrow (BM) samples for stage-specific abnormalities during terminal erythroid differentiation (TED) from 221 samples (MDS, n = 205 from 113 unique patients; normal, n = 16) by measuring the surface expression of glycophorin A, band 3, and integrin α-4. Clinical and biologic associations were sought with presence or absence of TED and the specific stage of erythroid arrest. In 27% of MDS samples (56/205), there was no quantifiable TED documented by surface expression of integrin α-4 and band 3 by terminally differentiating erythroblasts. Absence of quantifiable TED was associated with a significantly worse overall survival (56 vs 103 months, P = .0001) and SRSF2 mutations (7/23, P < .05). In a multivariable Cox proportional hazards regression analysis, absence of TED remained independently significant across International Prognostic Scoring System-Revised (IPSS-R) categories, myeloid/erythroid ratio, and mutations in several genes. In 149/205 MDS samples, the proportion of cells undergoing TED did not follow the expected 1:2:4:8:16 doubling pattern in successive stages. Absence of TED emerged as a powerful independent prognostic marker of poor overall survival across all IPSS-R categories in MDS, and SRSF2 mutations were more frequently associated with absence of TED.

Isolation and transcriptome analyses of human erythroid progenitors: BFU-E and CFU-E.

Burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) cells are erythroid progenitors traditionally defined by colony assays. We developed a flow cytometry-based strategy for isolating human BFU-E and CFU-E cells based on the changes in expression of cell surface markers during in vitro erythroid cell culture. BFU-E and CFU-E are characterized by CD45(+)GPA(-)IL-3R(-)CD34(+)CD36(-)CD71(low) and CD45(+)GPA(-)IL-3R(-)CD34(-)CD36(+)CD71(high) phenotypes, respectively. Colony assays validated phenotypic assignment giving rise to BFU-E and CFU-E colonies, both at a purity of ∼90%. The BFU-E colony forming ability of CD45(+)GPA(-)IL-3R(-)CD34(+)CD36(-)CD71(low) cells required stem cell factor and erythropoietin, while the CFU-E colony forming ability of CD45(+)GPA(-)IL-3R(-)CD34(-)CD36(+)CD71(high) cells required only erythropoietin. Bioinformatic analysis of the RNA-sequencing data revealed unique transcriptomes at each differentiation stage. The sorting strategy was validated in uncultured primary cells isolated from bone marrow, cord blood, and peripheral blood, indicating that marker expression is not an artifact of in vitro cell culture, but represents an in vivo characteristic of erythroid progenitor populations. The ability to isolate highly pure human BFU-E and CFU-E progenitors will enable detailed cellular and molecular characterization of these distinct progenitor populations and define their contribution to disordered erythropoiesis in inherited and acquired hematologic disease. Our data provides an important resource for future studies of human erythropoiesis.

Flagellin modulates TIM4 expression in mast cells.

T-helper (Th) 2 polarization functions in a number of immune diseases, but their pathogenesis needs further investigation. Some microbial products or components are strong adjuvants in the creation of mouse models of Th2 polarization. T cell immunoglobulin mucin molecule (TIM) 4 is a facilitator in the initiation of Th2 response. This study looks at the role of one of the microbial products, flagellin (FGN), in the induction of TIM4 expression in mast cells. Bone marrow derived mast cells (BMMC) were generated. Induction of TIM4 in mast cells was assessed in both experiments in vitro and in vivo. The signal transducer and activator of transcription 6 (Stat6) phosphorylation in BMMC were assessed by Western blotting. A coculture model with FGN-primed BMMC and naïve CD4(+) T cells was employed to assess FGN in facilitating the expression of TIM4 in mast cells. After exposure to FGN, TIM4 levels were significantly increased in BMMC and mast cells of the mouse intestine, which was accompanied by increased STAT6 phosphorylation. Culture with FGN-primed BMMC, naïve CD4(+) T cells developed into Th2 cells by a TIM4-dependent manner. We conclude that FGN can induce mast cells to express TIM4, which helps initiate Th2 polarization.

Isolation and functional characterization of human erythroblasts at distinct stages: implications for understanding of normal and disordered erythropoiesis in vivo.

Terminal erythroid differentiation starts from morphologically recognizable proerythroblasts that proliferate and differentiate to generate red cells. Although this process has been extensively studied in mice, its characterization in humans is limited. By examining the dynamic changes of expression of membrane proteins during in vitro human terminal erythroid differentiation, we identified band 3 and α4 integrin as optimal surface markers for isolating 5 morphologically distinct populations at successive developmental stages. Functional analysis revealed that these purified cell populations have distinct mitotic capacity. Use of band 3 and α4 integrin enabled us to isolate erythroblasts at specific developmental stages from primary human bone marrow. The ratio of erythroblasts at successive stages followed the predicted 1:2:4:8:16 pattern. In contrast, bone marrows from myelodysplastic syndrome patients exhibited altered terminal erythroid differentiation profiles. Thus, our findings not only provide new insights into the genesis of the red cell membrane during human terminal erythroid differentiation but also offer a means of isolating and quantifying each developmental stage during terminal erythropoiesis in vivo. Our findings should facilitate a comprehensive cellular and molecular characterization of each specific developmental stage of human erythroblasts and should provide a powerful means of identifying stage-specific defects in diseases associated with pathological erythropoiesis.

Quantitative analysis of murine terminal erythroid differentiation in vivo: novel method to study normal and disordered erythropoiesis.

Terminal erythroid differentiation is the process during which proerythroblasts differentiate to produce enucleated reticulocytes. Although it is well established that during murine erythropoiesis in vivo, 1 proerythroblast undergoes 3 mitosis to generate sequentially 2 basophilic, 4 polychromatic, and 8 orthochromatic erythroblasts, currently there is no method to quantitatively monitor this highly regulated process. Here we outline a method that distinguishes each distinct stage of erythroid differentiation in cells from mouse bone marrow and spleen based on expression levels of TER119, CD44, and cell size. Quantitative analysis revealed that the ratio of proerythroblasts:basophilic:polychromatic:orthromatic erythroblasts follows the expected 1:2:4:8 ratio, reflecting the physiologic progression of terminal erythroid differentiation in normal mice. Moreover, in 2 stress erythropoiesis mouse models, phlebotomy-induced acute anemia and chronic hemolytic anemia because of 4.1R deficiency, the ratio of these erythroblast populations remains the same as that of wild-type bone marrow. In contrast, in anemic ß-thalassemia intermedia mice, there is altered progression which is restored to normal by transferrin treatment which was previously shown to ameliorate the anemic phenotype. The means to quantitate in vivo murine erythropoiesis using our approach will probably have broad application in the study of altered erythropoiesis in various red cell disorders.