Studies of erythroblast function in congenital dyserythropoietic anaemia, type I: evidence of impaired DNA, RNA, and protein synthesis and unbalanced globin chain synthesis in ultrastructurally abnormal cells.

Two patients with congenital dyserythropoietic anaemia, type I (CDA) were studied. Their blood reticulocytes showed unbalanced globin chain synthesis with increased alpha:beta globin chain synthesis ratios. A high proportion of the erythroblasts displayed the characteristic "Swiss cheese" abnormality of the nuclear chromatin and some also showed cytoplasmic intrusions lined with nuclear membrane within the nucleus. Occasional erythroblast profiles contained intracytoplasmic inclusions that were ultrastructurally indistinguishable from precipitated alpha chains. The technique of combined Feulgen microspectrophotometry and 3H-thymidine autoradiography showed gross abnormalities of proliferation in the early polychromatic erythroblasts. The proliferative abnormalities included an arrest of DNA synthesis after the progress of cells through part of the S phase and the formation of several mononucleate and binucleate cells with hypertetraploid total DNA contents. The bone marrow cells gave a normal deoxyuridine suppressed value, indicating that there was no impairment of the methylation of deoxyuridylate. Electron microscope autoradiographic studies showed that a high proportion of the erythroblasts with the "Swiss cheese" nuclear abnormality suffered from a severe impairment, or arrest of DNA, RNA, and protein synthesis.     

Ultrastructure of bone marrow in patients with visceral leishmaniasis.

Ultrastructural studies were performed on bone marrow aspirates from three patients with visceral leishmaniasis. The patients were moderately anaemic but showed a suboptimal increase in the absolute reticulocyte count. Serum and red cell folate concentrations and serum vitamin B12 concentrations were normal in all three cases, and serum ferritin concentrations were normal or increased. The bone marrows were hypercellular and showed erythroid hyperplasia; a high proportion of the erythroblasts showed dyserythropoietic changes. Amastigote forms of Leishmania donovani were found within bone marrow macrophages and within occasional neutrophil and eosinophil granulocytes. Electron microscopy showed the presence of many abnormal cells, which probably represented immature erythroblasts with giant lysosomes. These cells were often large, usually contained immature nuclei with relatively little condensed chromatin, had 1-20 electron dense cytoplasmic granules with an average diameter of 0.5 micron, and regularly displayed substantial rhopheocytotic activity. A few abnormal cells and intermediate and late erythroblasts appeared to have been phagocytosed by macrophages. The data indicate that dyserythropoiesis and ineffective erythropoiesis have a role in the pathogenesis of the anaemia of at least some cases of kala-azar.     

Intracellular hemoglobin-a specific marker for erythroid cells in paraffin sections. An immunoperoxidase study of normal, megaloblastic, and dysplastic erythropoiesis, including erythroleukemia and other myeloproliferative disorders.

Intracellular hemoglobin represents an excellent marker for specific characterization of normal, megaloblastic, or dysplastic erythroid cells in paraffin sections. Using an immunoperoxidase indirect sandwich technique for detection of intracellular hemoglobin, erythroid cells at all stages of maturation were readily identified in bone marrow biopsies (58 specimens total) with a) normal erythropoiesis, b) megalobastic erythropoiesis, and c) various myeloproliferative disorders, including erythroleukemia. In other tissues (6 spleens, 2 lymph nodes, 1 liver) with extramedullary hematopoiesis, erythroid cells were similarly defined on the basis of this immunohistochemical method. Initial fixation in Zenker's-acetic acid solution (employed for bone marrow biopsies), B5 solution, or formalin, appeared equally effective in preserving the antigenicity of intracellular human hemoglobin. This sensitive and specific immunoperoxidase technique for erythroid cell characterization is particularly applicable to tissues with abnormal erythropoiesis, in which precise cell identification generally presents a diagnostic problem.     

Hydroxyurea treatment of myeloproliferative disorders. Macro-megaloblastic blood and bone marrow changes

Blood and bone marrow changes induced by continuous low-dose hydroxyurea treatment are described. A linear increase in mean red cell volume was observed after onset of therapy. The entire normocyte population was replaced by abnormally large erythrocytes within 150 days. The bone marrow morphology changed in megaloblastic direction. Bone marrow iron stores and number of sideroblasts increased, findings compatible with ineffective erythropoiesis. Serum folate and cobalamin levels remained normal. These morphologic changes might cause confusion when examining blood or bone marrow samples from patients treated with hydroxyurea.     

Proliferation and maturation of human bone marrow cells in infectious diseases

In 6 patients with various types of infectious disease an extended study of proliferation and maturation of erythropoiesis and granulocytopoiesis was performed. By means of quantitative 14C-autoradiography DNA synthesis time and labeling index were determined in every morphologically defined cell compartment of both lineages. With these parameters and the relative frequency of cells in the various compartments cell cycle times, relative cell production rates and maturation indices were determined. A general labeling index reduction and prolongation of DNA synthesis time was observed which was statistically significant in the majority of compartments. As a consequence, cell cycle times were prolonged throughout, the deviation from normal increasing with advancing maturation in both lineages. Relative cell production was normal in myelocytes, but elevated in myeloblasts and promyelocytes. On the other hand, proerythroblasts and basophilic erythroblasts showed normal relative cell production rates, while a significantly reduced value was found in polychromatic erythroblasts. The maturation index in both lineages was reduced by roughly 50%. Since cell cycle times were generally prolonged, the most significant deviations from normal being present in the latest proliferative compartments, the low maturation indices are discussed in the light of ineffective erythro- and granulocytopoiesis. Premature cell death in the bone marrow is suggested to be a significant factor in particular cases of infectious disease.     

Unusual megaloblastic anaemia wiht multinucleate erythroblasts: two cases with septicaemia and acute renal failure.

The case histories and blood pictures of two patients who had cardiac lesions, septicaemia, and renal failure and terminally developed a leucoerythroblastic anaemia with megloblastic features associated with multinucleate erythroblasts, are described. Though folate deficiency may have made a minor contribution to the blood abnormalities, it is considered that some other disturbance in erythropoiesis was responsible for the bizarre blood and bone marrow changes in these patients. Similar cases reported in the earlier literature are reviewed.     

Myelodysplastic syndromes: Immunohistochemical and morphometric evaluation of proliferative activity in erythropoiesis and endoreduplicative capacity of megakaryocytes

An immunohistochemical and morphometric analysis was performed on bone marrow trephine biopsies in 40 patients with primary myelodysplastic syndromes (MDS) to evaluate the proliferative activity in erythropoiesis and the endoreduplicative capacity of megakaryocytes. Control groups included normal bone marrow and marrow from cases presenting with pernicious anaemia. Double-immunostaining was applied with a monoclonal antibody (PC10) directed against proliferating cell nuclear antigen (PCNA), followed by antibodies against glycophorin C (Ret40f) or platelet glycoprotein IIIa (Y2/51-CD61) for the identification of the erythroid and megakaryocytic cell lineage. Comparison with normal bone marrow showed a reduction of erythropoiesis accompanied by an increase in atypical (micro-) megakaryocytes. Erythroid precursors displayed significant enhancement of PCNA-immunostaining. Megakaryocytes showed no increase in the relative frequency of PC10-positive cells (PCNA-labelling index). In pernicious anaemia, predominance of macrocytic-megaloblastoid erythropoiesis was associated with a striking increase in PCNA-labelling. Cell kinetic studies in this disorder revealed an abnormal arrest, particularly in S-phase which generates an over-expression of PCNA. Similar conditions were believed to be present in MDS with secondary folate deficiency. This mechanism explains the relatively high rate of positively-reacting pro- and erythroblasts which is not invariably accompanied by an increase in cell proliferation. Determination of megakaryocyte size and PCNA-staining capacity resulted in a significant increase in PC10-positive cells among micromegakaryocytes. Our findings on this cell lineage are in keeping with the assumption of a block in endoreduplicative activity at higher ploidy levels, associated with an apparently not-deregulated endomitosis in small-sized megakaryocytes of lower ploidy stages.Supported by a grant from the Deutsche Forschungsgemeinschaft (DFG-Th 390/1-3)     

Ultrastructure of bone marrow in chicks inoculated with chicken anaemia agent (MSB1-TK5803 strain)

Ultrastructural changes of the bone marrow in chicks inoculated with chicken anaemia agent (CAA: MSB1-TK5803 strain) and age-matched controls are described. Erythropoiesis in the lumen of the intravascular spaces (sinuses) of unaffected bone marrow were classed into four consecutive stages according to cell morphology: proerythroblasts, basophilic erythroblasts, polychromatophilic erythroblasts and erythrocytes. In the early stage of infection, haematopoietic cells showed irregular plasma membrane, vacuolisation, formation of pseudopods and electron-opaque regions in the cytoplasm as well as intranuclear inclusions consisting of fine granular or homogeneous materials. Aggregation of virus-like particles, of 14 nm in diameter, was rarely observed in the degenerative haematopoietic cells. Subsequently, an increase in numbers of macrophages with engulfed degenerative and necrotic haematopoietic cells and plasma cells with prominent Golgi complex and well developed rough endoplasmic reticulum was observed in the anaemic stage. Although immature cells were rarely seen on day 12 of postinoculation (pi), active erythropoiesis resumed on day 20 pi or later.     

Ability of peritoneal exudate cells to trigger various mechanisms of erythroid differentiation at different terms after massive blood loss in mice

Thirty minutes after massive blood loss, peritoneal cells gained the ability to trigger reparative erythropoiesis in the bone marrow of normal syngeneic recipients. This was manifested in proliferation of oxyphilic erythroblasts and activation of the reserve pathway of erythroid differentiation 4 days after cell transplantation. The maximum transfer capacity of peritoneal cells was observed 4 h after blood loss, but 4 days later they only initiated mitoses in oxyphilic erythroblasts. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 5, pp. 521–524, May, 2000     

Progenitor cells of erythroblasts: an in vitro investigation of erythropoietin-responsive cells of guinea pig bone marrow

The experiments were designed to test whether or not erythroblast progenitor cell function could be demonstrated in a morphological cell type designated as "transitional cells." Two cell fractions, were obtained from the bone marrow of normal and polycythemic guinea pigs. One fraction (F1) was enriched in transitional cells and contained few, if any, other cell types which could be considered as candidates for erythropoietin responsive cells (ERC). The other fraction (F2) contained undifferentiated blast cells as well as transitional cells. The effect of human urinary erythropoiesis stimulating factors (ESF) on heme synthesis was compared in these two fractions by measuring 59Fe incorporation into heme. ESF was more effective in stimulating heme synthesis in guinea pig bone marrow cells than homologous sera obtained from anemic or hypoxic animals. The majority of ERC sedimented in F2, but the stimulation index was comparable in the two fractions. It was confirmed by radioautography that the ESF response in F1 was due to the generation of proerythroblasts and basophilic erythroblasts that incorporated 55Fe. The generation of these cells in F1 was dependent on the addition of ESF to the cultures, whereas 55Fe-labeled erythroblasts were recovered from cultured of F2 not supplemented with ESF. ESF induced a proportion of transitional cells to incorporate 55Fe in both F1 and F2. Transitional cells were the only cell type in which heme synthesis was dependent on ESF. in other cells of clearly nonerythroid morphology (mononuclear phagocytes and reticular cells), 55Fe incorporation occurred independent of ESF. Although the fractionation procedure employed is unsuitable for the separation of ERC from bone marrow, it permitted the enrichment of transitional cells, a cell type defined by morphology. Radioautography with 55Fe identified a proportion of these cells as ERC in both F1 and F2 fractions of bone marrow obtained from normal and polycythemic guinea pigs. Although there may be other cell types in F2 capable of responding to ESF, the present studies show that some transitional cells function as progenitors of erythroblasts because they respond to ESF by initiation of heme synthesis and by transformation into the earliest recognizable erythroid cells.     

Studium der Proliferationsdynamik von Blutzellen mit Hilfe cytophotometrischer DNS-Bestimmungen in der Einzelzelle

Zusammenfassung Es wurden Ergebnisse feulgenphotometrischer DNS-Bestimmungen an roten Vorstufen des Knochenmarks bei 7 hämatologisch Gesunden, 2 Patienten mit frischer Blutung, 9 Patienten mit einer hämolytischen Anämie, 4 Patienten mit einer Eisenmangelanämie, 6 Patienten mit einer Polycythaemia vera bzw. Polyglobulie, 4 Patienten mit einer Pancytopenie, 5 Patienten im Ablauf einer medikamentös allergischen Agranulocytose und 9 Patienten mit einer megaloblastären Anämie vorgelegt.1. Im Knochenmark hämatologisch Gesunder weisen rund 2/3 der roten Vorstufen annähernd 2n- bzw. 2c-DNS-Werte auf. Der Rest der Zellen befindet sich in prämitotischer DNS-Synthesephase oder hat bereits vor Eintritt in die neue Mitose den DNS-Gehalt verdoppelt. Bei keinem der untersuchten Patienten ließ sich ein Erythroblast mit einem 6n- oder 8n-DNS-Gehalt nachweisen.2. Der nach quantitativen DNS-Bestimmungen errechnete prozentuale Anteil in DNS-Synthese befindlicher roter Vorstufen entspricht den Ergebnissen nach³H-Thymidininkubation.3. Akute Störungen innerhalb der Erythropoese infolge einer frischen Blutung, eines akuten hämolytischen Schubes, einer medikamentös-allergisch ausgelösten Markschädigung oder durch eine Markumwandlung nach hochdosierter Gabe von Vitamin B₁₂ im B₁₂-Mangelzustand führen vorübergehend zu einer Änderung des Zellanteils in DNS-Synthese. Länger andauernde Störungen (persistierende hämolytische Anämie, Polycythaemie, Polyglobulie) weisen jedoch gegenüber der normalen Erythropoese keine Zeichen einer veränderten Zellregeneration auf. Der Mehrbedarf an Erythrocyten dürfte in diesen Fällen durch die Ausdehnung des erythropoetisch aktiven Knochenmarks gedeckt werden. Bei Pancytopenien findet sich neben einer Verkleinerung der Gesamtzellzahl im Knochenmark eine Verminderung DNS-synthetisierender Zellen.4. Eine umschriebene Häufung roter Vorstufen mit einem DNS-Gehalt in der Mitte zwischen 2n- und 4n-Werten weist bei megaloblastären Anämien auf einen verlangsamten Ablauf der DNS-Synthese bzw. auf einen Untergang einzelner roter Vorstufen während der DNS-Verdoppelungsphase im Sinne einer ineffektiven Erythropoese hin.5. Als Besonderheit fällt nach Radiophosphorbehandlung und bei megaloblastären Anämien wie bei Anämie infolge Glutathionreductasemangel eine Vermehrung der Zellen mit verdoppeltem (4n)-DNS-Gehalt (G₂-Phase) auf. Da dieser Befund nicht durch eine Zunahme DNS-Synthetisierender Zellen und damit einen vermehrten Eintritt der Zellen in die G₂-Phase erklärt werden kann, muß eine Verlängerung der G₂-Phase und ein verzögerter Mitosebeginn angenommen werden.

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Summary Red cell precursors was investigated by means of Feulgen-photometric measurements in the bone marrow from 7 haematological normal persons, 2 patients with acute bleeding, 9 patients with haemolytic anaemia, 6 patients with iron-dificiency anaemia, 6 patients with polycythaemia, 4 patients with pancytopenia, 5 patients during bone marrow regeneration of agranulocytosis and 9 patient with megaloblastic anaemia.1. 2/3 of red cell precursors shows 2n (2c) DNA-values in normal bone marrow. The other cells are in DNA-synthesis, or they have already doubled their premitotic DNA-content before the onset of mitosis. We have never found erythroblasts with 6n (6c) or 8n (8c) DNA-values.2. The percentage of DNA synthesizing cells calculated by Feulgen-photometry corresponds to the labelling index by means of³H-thymidine-autoradiography.3. Disturbances in erythropoiesis in the course of acute bleeding, acute haemolysis, drug induced allergic bone marrow insufficiency and in the course of regeneration of megaloblastic bone marrow after vitamine B₁₂ injection leads to acute changes in the percentage of cells in DNA-synthesis. No changes of the percentage of red cell precursors in DNA-synthesis takes place in cases of prolonged bone marrow irritation in persistent haemolytic anaemia and in polycythaemia. Augmentation of the erythropoietic active bone marrow restored the additional required erythrocytes in these diseases. A diminution of active bone marrow cells and a decrease of DNA synthesizing cells are findings in pancytopenia.4. A distinct augmentation of red cell precursors with a DNA-content in the middle of 2n and 4n (2c–4c) values in megaloblastic anaemia points at an inhibition of DNA-synthesis in the middle of the DNA synthesis period or of cell death before completion of DNA replication (as a sign of ineffective erythropoiesis).5. An increase of red cell precursors with 4n (4c) DNA-values in the G₂-period of generation cycle takes place after treatment with³²P, in megaloblastic anaemia and in anaemia in Glutathionreductase deficiency. This augmentation of G₂-cells is not caused by an increase of DNA synthesizing cells. It indicates therefore a prolongation of G₂-period and an inhibition of onset of mitosis.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.

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Herrn Prof. Dr.H. E. Bock zum 65. Geburtstag.     

Iron metabolism and "sports anemia". II. A hematological comparison of elite runners and control subjects

A hematological comparison was performed between 43 middle and long distance male runners and 119 male controls. The hematocrit, serum iron, transferrin saturation and serum ferritin values were significantly lower in the athletes. The amount of bone marrow hemosiderin was also lower in the athletes than in a group of non-athletic men of the same age. Even if these values were clearly lower than in the controls, they were not low enough to indicate iron deficiency. The observations that sideroblast counts in bone marrow smears were normal and that both red cell indices and red cell protoporphyrin were normal strongly support the conclusion that lack of iron had not limitated erythropoiesis or the formation of an optimal red cell mass. Low serum haptoglobin values in most athletes indicated an increased intravascular hemolysis. As the hemoglobin-haptoglobin complex formed is taken up by hepatocytes, this implies that there is a shift in the red cell catabolism in these athletes from the reticuloendothelial system to the hepatocytes. This shift may explain the paradoxical findings of low serum ferritin concentrations and reduced contents of bone marrow hemosiderin. This is consistent with the observed normal erythropoiesis. It was concluded that runners "anemia" is no true anemia and not caused by iron deficiency. "Sports anemia" is thus no indication for routine iron supplementation.     

Invasion of Erythroblasts by Pasmodium vivax: A New Mechanism Contributing to Malarial Anemia

Severe malarial anemia causes considerable mortality and morbidity in endemic areas. Possible mechanisms underlying the anemia include lysis of parasitized and nonparasitized red cells as well as parasite product-mediated effects on erythropoiesis. The latter include suppression of erythropoiesis, dyserythropoiesis, and ineffective erythropoiesis. Present transmission electron microscope data in two cases of Pasmodium vivax malaria show a hitherto undescribed mechanism contributing to malarial anemia, namely, infection of erythroblasts by parasites and their subsequent degradation. No parasites were detected in the peripheral blood but parasites were found in the bone marrow. These findings emphasise the value of bone marrow examination in the diagnosis and eradication of malaria.     

Malignant lymphoma in congenital dyserythropoietic anaemia type III.

A 60 year old woman with congenital dyserythropoietic anaemia (CDA) type III developed a malignant T cell lymphoma with cutaneous and widespread nodal involvement. Bone marrow aspirates showed erythroid hyperplasia and dyserythropoiesis with multinucleate erythroblasts and gigantoblasts, in keeping with CDA type III. Electron microscopy showed multinucleate erythroblasts with notably irregular nuclear outlines and intranuclear clefts. The development of malignant lymphoma in this patient, together with a documented high prevalence of monoclonal gammopathy and multiple myeloma and a single case of Hodgkin's disease, may indicate an increased incidence of lymphoproliferative disease in CDA type III.     

The regenerating liver: A site of erythropoiesis in the adult long-evans rat

Erythropoiesis, which is primarily hepatic in the rat during fetal and early neonatal life, shifts almost entirely to the bone marrow in the neonatal-adolescent stage of development. In the adult, extramedullary erythropoiesis has been demonstrated in the liver and spleen under certain pathological conditions when bone marrow red cell production is insufficient. In the present study, erythropoietic foci have been found in young-adult rat liver regenerating 24–72 hr after subtotal hepatectomy. This erythropoiesis is both extravascular and sinusoidal, with some erythroblastic islands noted. The centrolobular hepatic area contains the highest concentration of erythroblasts. Peripheral blood reticulocytosis coincides with the appearance of these cells and this is considered as an indicator of effective erythropoiesis. Liver regenerating after partial hepatectomy produces significant quantities of erythropoietin (Ep) in response to hypoxia. Subtotal hepatectomy may confer upon the adult liver the ability to revert to a fetal-like condition both in its ability to produce Ep and to function as a hematopoietic inductive microenvironment for erythropoiesis.     

A histological study and three-dimensional reconstruction of F4/80-positive reticular cells and macrophages at the onset of murine bone marrow hematopoiesis

Adult bone marrow consists of two different compartments, a vascular compartment of sinusoid and a hematopoietic compartment consisting of stromal cells and hematopoietic cells. In the hematopoietic compartment, stromal cells play an important role in the formation of the microenvironment for hematopoiesis. To clarify the relationship between hematopoietic cells and stromal cells, particularly reticular cells and macrophages, we examined the femur bone marrow of ICR mouse fetuses and neonates using F4/80 immunostaining and three-dimensional reconstruction under light and electron microscopy. In the fetal femurs, the marrow cavity formed early from 15 days of gestation, and it showed a marked increase in volume thereafter. On the basis of the appearance of hematopoietic cells, marrow development could be classified into two stages, a pre-hematopoietic stage from 15 days of gestation to two days of age, and a beginning stage of hematopoiesis thereafter. The pre-hematopoietic bone marrow contains not only stromal reticular cells but also macrophages, and both types of stromal cells were strongly positive to F4/80 monoclonal antibody. These F4/80-positive reticular cells had a triangular cell profile with long and slender cytoplasmic processes. Reticular cells often contained large lysosomes of not only dying neutrophils but also erythroblast nuclei. A few erythroblasts accumulated around the processes, and the number of erythroblasts around reticular cells increased with bone marrow development. On the other hand, macrophages were located either close to sinusoids or in sinusoid lumen, and a close relationship to hematopoietic cells was hardly noticeable. At the beginning stage of hematopoiesis, F4/80-positive reticular cells extended their long and slender cytoplasmic processes, and the number and length of the processes appeared markedly increased. The three-dimensional cell surface of the F4/80-positive reticular cells became very complex. Numerous erythroblasts accumulated around the processes, and erythroblastic islands could gradually be recognized after four days of age. In the erythroblastic islands, central reticular cells were F4/80-positive and contained numerous large phagosomes originating from the expelled nuclei of erythroblasts. Although macrophages contained large phagosomes, the relationship between macrophages and hematopoietic cells could not clearly be elucidated even at the beginning stage of hematopoiesis. At the onset of bone marrow hematopoiesis, the hematopoietic compartment contained two kinds of F4/80-positive phagocytes, i.e., reticular cells and macrophages. In marrow erythroblastic islands, not macrophages but F4/80-positive reticular cells were located at the center of each island.     

人脐血间充质干细胞移植修复骨髓造血损伤

文题释义：间充质干细胞：是一种多功能干细胞,由胚胎发育早期的中胚层发展而来,存在于人的各种组织、器官中,如骨、软骨、脂肪、外周血和肌肉等。骨髓组织中的间充质干细胞最多,但其在骨髓细胞中的比例仍很低,只有0.01%-1.00%,且年龄越大其含量越少,骨髓中的间充质干细胞分化能力也呈下降趋势。与骨髓相比,脐血中所含的间充质干细胞更加原始,因而有更强的增殖、分化能力。相较于骨髓间充质干细胞而言,人脐血间充质干细胞具有来源广泛、取材方便、无伦理方面的限制,使得人脐血间充质干细胞成为再生医学中的另一重要来源。骨髓造血损伤动物模型：建立骨髓造血损伤动物模型的方法有很多,主要分为物理方法、化学方法及物理化学方法等。物理方法包括各种射线,如X射线等,化学方法主要指以环磷酰胺为代表的烷化剂类化疗药物,而物理化学方法也叫混合性方法,联合应用放射线和化疗药物建立动物模型。  摘要背景：大多数研究间充质干细胞体外培养对造血干细胞的增殖作用和骨髓间充质干细胞移植可降低辐照引起的造血细胞死亡,增加骨髓细胞存活,修复造血功能,而少有研究人脐血间充质干细胞移植对骨髓造血损伤的修复。目的：探讨人脐血间充质干细胞对骨髓造血微环境的修复情况。方法：选用雄性BALB/c小鼠随机分为3组,实验组和对照组小鼠进行总剂量为6 Gy的X射线全身照射,建立骨髓造血损伤模型,正常组为未经处理的正常小鼠。实验组小鼠照射当天经尾静脉输入CM-DiL标记的人脐血间充质干细胞5×10⁶/只(0.2 mL),对照组和正常组经尾静脉输入生理盐水0.2 mL,移植后第1,5,7,14,21天观察外周血血象恢复情况和骨髓造血微环境修复情况。结果与结论：①外周血常规：移植后第1,5,7天,实验组和对照组小鼠与正常组小鼠比较,白细胞、血小板、红细胞计数及血红蛋白浓度进行性下降,第7天下降最为明显,移植后第14天三系较前有所恢复,移植后第21天基本恢复正常,与实验组相比,对照组三系下降更为明显,移植后第14天实验组较对照组恢复快;②骨髓涂片情况：移植后第1,5,7,14天实验组及对照组小鼠骨髓出现造血功能抑制,以第7天最为明显,移植后第14天骨髓增生较前有所恢复,实验组优于对照组;移植后第21天实验组及对照组小鼠骨髓造血功能恢复,与正常组相比无差异;③骨髓病理切片情况：移植后第1,5,7,14天实验组及对照组小鼠骨髓出现造血功能抑制;移植后第14天实验组及对照组小鼠的骨髓造血功能较前开始恢复,实验组小鼠的骨髓增生情况优于对照组小鼠, 移植后第21天实验组及对照组小鼠骨髓增生情况与正常组比较无差异;④结果表明,人脐血间充质干细胞对骨髓造血功能恢复均有明显促进作用。ORCID: 0000-0002-7547-9664(高坤莉) 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

Mononuclear phagocyte proliferation, maturation and function.

The mononuclear phagocytic system is a continuum of cells beginning with the bone marrow monoblast and promonocyte, through the monocyte to the larger tissue macrophages and multinucleate giant cells. This system of cells is widely distributed throughout the body in the blood and bone marrow; the pleural, peritoneal, and alveolar spaces; the lymph nodes, spleen, liver, and other parenchymal organs. The activity and composition of the cell varies with the level of maturation, changes in cellular environment, and with various cellular activities. The monocyte-macrophage group of cells plays an active role in defense reactions against certain microorganisms, and in the removal of dying cells and cell debris. They are an integral part of both the inductive phase of the immune response, and of cell-mediated immune reactions. In addition, they probably play a role in the defence against spontaneously arising tumours, in the control of granulopoiesis, and possibly in erythropoiesis.     

Equine bone marrow: a quantitative analysis of erythroid maturation

The equine bone marrow responds to blood loss by increased erythropoiesis, only releasing reticulocytes into the peripheral circulation in severe chronic anemia. We have used morphometric analysis based on electron microscopy of the equine marrow to examine the maturation and release of reticulocytes. Developing red cells in the bone marrows of normal and chronically anemic horses were divided into four stages: early, intermediate, late-stage erythroblasts, and reticulocytes. Morphometric analysis of each stage included volume density of mitochondria per micron3 of cytoplasm, surface area of the outer mitochondrial membrane per unit volume of mitochondria, and the number of ribosomes per unit volume of cytoplasm (total, clustered, single). Matched t tests between normal and anemic animals showed significant differences (P less than or equal to .001) for volume density of mitochondria and numbers of ribosomes only at the reticulocyte stage. The large reticulocyte produced and released in chronic anemia may be best explained by a skipped mitotic division.     

Different sequences of expression of band 3, spectrin, and ankyrin during normal erythropoiesis and erythroleukemia.

Expression of the erythrocyte anion exchanger band 3, and ankyrin and spectrin, two cytoskeletal proteins of the red blood cell membrane, was studied by immunofluorescence using: 1) smears of human bone marrow from healthy donors and from a patient with erythroleukemia, 2) human red blood cell precursors grown in cell culture, and 3) murine erythroleukemia cells grown in cell culture. Double immunostaining with antibodies to band 3 in combination with spectrin or ankyrin revealed that these proteins become expressed synchronously during normal human erythropoiesis. In contrast, both murine erythroleukemia cells (induced by fibronectin and dimethyl sulfoxide to differentiate in vitro) and erythroblasts from a patient suffering from erythroleukemia displayed distinct asynchronicity in expression of these proteins, ie, ankyrin and spectrin were synthesized first, followed by band 3 at a later stage of erythroid development. After the onset of band 3 expression in human erythroleukemia cells, an increase of membrane-associated fluorescence was detectable for both ankyrin and spectrin, supporting the general view that band 3 promotes assembly of the membrane cytoskeleton. These findings indicate that the current concept of a sequential expression of spectrin/ankyrin and band 3 is valid only for erythroleukemia cells or transformed erythropoietic cell lines but does not occur in normal erythropoiesis, during which these proteins become expressed simultaneously.