The mechanism of expansion of late erythroid progenitors during erythroid regeneration: target cells and effects of erythropoietin and interleukin-3

Through immunologic means we have been able to separate primate bone marrow cells into populations containing late erythroid progenitors (colony forming units [CFUe] and e-clusters) but depleted of early erythroid progenitors (burst-forming units [BFUe]) or populations enriched in BFUe in relation to late progenitors. We used these fractionated populations in a two stage liquid/semisolid culture system and have assessed the effect of erythropoietin (Epo) and interleukin-3 (IL-3) on the proliferation and differentiation of erythroid progenitors in the presence or absence of early progenitors. We found that populations that contained CFUe but were depleted of BFUe failed to show any amplification of CFUe or e-clusters in the presence of Epo (or Epo plus IL-3). In contrast, populations containing BFUe yielded a striking (sixfold for CFUe; 23-fold for e-clusters) expansion of late progenitors in the presence of Epo. Maximum amplification (15-fold for CFUe; 32-fold for e-clusters) was achieved when both IL-3 and Epo were present in culture. Our results imply that CFUe and e-clusters lack the capacity to amplify their numbers and suggests that the expansion of late erythroid progenitors during rapid erythroid regeneration is accomplished by influx of BFUe rather than amplification of CFUe. These data are of relevance to models of acute marrow expansion and to the mechanism of activation of fetal hemoglobin production during rapid erythroid regeneration.

Lymphoid blast crisis in a patient with Philadelphia-chromosome-negative chronic myelocytic leukemia

A 24-year-old man with Philadelphia-chromosome (Ph)-negative chronic myelocytic leukemia (CML) developed lymphoid blast crisis. In the chronic phase, karyotype was normal and the clinical and hematological features were indistinguishable from those of Ph-positive CML. Rearrangement of the breakpoint cluster region (bcr) was observed. In the blast phase, blast cells showed early B-cell phenotype (CALLA+, Ia+, TdT+) with a rearranged immunoglobulin heavy-chain gene joining region (JH). By using an immunoblotting method and antiphosphotyrosine sera, P210bcr-abl protein was detected. The patient responded well to vincristine and prednisolone (VP) therapy. These findings support the concept that Ph-negative bcr+ CML can behave in a very similar fashion to Ph-positive CML, not only in the clinical features of the chronic phase but also in the manner of the blast crisis.

Fetal hemoglobin synthesis in vivo: direct evidence for control at the level of erythroid progenitors

To test directly whether the control of fetal hemoglobin (HbF) in the adult takes place at the level of erythroid progenitors or at the level of erythroblasts, we treated animals with high doses of erythropoietin and examined the effects of this manipulation on the globin gene programs of erythroid progenitors. We found that administration of erythropoietin produced a rapid expansion of all classes of erythroid progenitors. Almost all the expansion of colony-forming units-erythroid and 46-56% of erythroid clusters was due to the increase of HbF-programmed erythroid progenitors. The expansion of HbF-programmed erythroid progenitors was followed, 2-3 days later, by a wave of reticulocytes containing HbF in the peripheral blood. These results provide direct in vivo evidence that fetal-globin expression in the adult is controlled at the level of erythroid progenitors.

Local antibody production and immune complex formation in rats experimentally infected with Angiostrongylus cantonensis

The systemic humoral immune responses and tissue localization of worm-antigen, antibodies (IgG), and complement (C3) were examined in rats experimentally infected with Angiostrongylus cantonensis. While the worms remained in the subarachnoid space, it was infiltrated with plasma cells and lymphoid cells containing IgM and IgG. When the infiltration of these cells became more pronounced, the serum antibody titer began to increase. At the same time, deposits of IgM, IgG, and C3 were found in the glomeruli of the kidney. A number of eggs were observed in the lungs, enclosed in granulomatous tissues. Infiltrates of plasma cells including IgM and IgG, and deposits of IgM, IgG, and C3 were detected around the eggs and in the granulomatous tissues. A marked increase in serum antibody was observed. A. cantonensis larvae induce local antibody (IgM and IgG) production in the central nervous system prior to an increase of serum antibody titer. Measurement of cerebrospinal fluid antibody titer at an early stage of infection may confirm infection. The larvae showed no evidence of damage in spite of marked local antibody production in the central nervous system. The eggs in the lungs stimulated both local and systemic antibody production, and immune complexes were formed in the lung and the circulatory system. Immune complexes may participate in the formation of granuloma.

Influence of maternal chlorpromazine on discrimination learning in rat offspring

Light-dark discrimination learning in rat offspring born to mothers treated with chlorpromazine was studied. Daily doses of 16 mg/kg, administered from gestation day 17 to day 21, had no effect on the acquisition of lever press responses and on the original discrimination learning. However, acquisition of the reversal learning was retarded. The same dose administered during the nursing period did not produce such behavioral changes. The results indicate that high doses of chlorpromazine administered during the peripartum period might cause learning impairment in the offspring.

Difference of bone marrow adipocyte colony-forming capacity between aplastic anemia and iron deficiency anemia

The bone marrow adipocyte colony-forming capacity (Adipo-CFC) in patients with aplastic anemia (AA), myelodysplastic syndrome (MDS) and iron deficiency anemia (IDA) was studied. Before treatment, Adipo-CFC in IDA was higher than that in AA and MDS. After treatment, Adipo-CFC decreased in IDA, but it increased in AA and MDS only at the responsive stage. In this context, it is suggested that increase of Adipo-CFC occurs during not only regenerating hemopoiesis but also accelerated erythropoiesis such as severe IDA. Colony-stimulating activity (CSA) production by marrow stromal cells (MSC) in AA was lower than that in normal subjects. Low Adipo-CFC and defective CSA production by MSC may explain in part the pathogenesis of microenvironmental defect in AA.

Regulation of biosynthesis and phosphorylation of P210bcr/abl protein during differentiation induction of K 562 cells

The changes of P210bcr/abl and other tyrosine phosphorylated proteins in K562 cells during growth and differentiation were studied by metabolic labeling with 32PO4 and immunoprecipitation with anti-phosphotyrosine sera. The anti-phosphotyrosine sera recognized P210bcr/abl and other phosphoproteins with mol wt of 150, 115, 100, 70 and 64 kD. The 2-day incubation of K562 cells with inducers for differentiation, hemin, sodium butyrate and TPA, decreased the level of P210bcr/abl protein and other phosphoproteins. Inhibitors of tyrosine protein kinase, amiloride and genistein, also reduced the phosphorylation of P210bcr/abl protein and other substrates, but did not induce differentiation of the cells. Although most of these additives inhibited the cell growth, cytotoxic agents such as adriamycin, vincristine and Ara-C did not affect the level of P210bcr/abl protein. The experiments using 35S-methionine labeled cells and the immunoprecipitation with anti-abl sera suggested that reduced biosynthesis but not dephosphorylation of P210bcr/abl protein mainly accounted for the reduction of P210bcr/abl protein reacting to anti-phosphotyrosine sera in differentiation-induced cells. These results indicate that the reduction of P210bcr/abl protein synthesis plays some roles in cellular differentiation of K562 cells.

Hematopoietic growth factors (BPA and Epo) induce the expressions of c-myc and c-fos proto-oncogenes in normal human erythroid progenitors

We investigated serial expressions of eight proto-oncogenes during in-vitro differentiation of normal human burst-forming unit, erythroid (BFU-E), and found that c-myc and c-fos are expressed in progenies of BFU-E. The expressions of the two proto-oncogenes correlated to the replating efficiency and adversely to erythroid differentiation. The absence of hematopoietic growth factors decreased the expressions, but the addition of erythropoietin together with burst promoting activity induced a re-expression of the c-myc and c-fos after 2 h of incubation. These observations suggest that the c-myc and c-fos proto-oncogenes have a physiological role in the proliferation of erythroid progenitors and that activations of the two proto-oncogenes are early cellular events after the stimulation by hematopoietic growth factors.

Regulation of erythropoietin and burst-promoting activity production in patients with aplastic anemia and iron deficiency anemia

To clarify the control mechanism of production of erythropoietic growth factors in anemic states, we compared erythropoietin (Epo) and burst-promoting activity (BPA) in patients with aplastic anemia and iron deficiency anemia, using in vitro erythroid progenitor assays. Although serum levels of Epo activity increased in the presence of anemia, the rise was more marked in patients with aplastic anemia. BPA was high only in the sera of aplastic anemia patients. Serum levels of BPA of patients with aplastic anemia negatively correlated with hemoglobin concentrations, while those of patients with iron deficiency anemia did not correlate. In 2 patients with aplastic anemia who responded well to androgen therapy, serum levels of Epo activity and BPA decreased after the hemopoiesis had recovered. These results suggest that serum levels of BPA do not rise in response to anemia only. The elevated BPA levels in sera in cases of aplastic anemia are probably related to a reduction in the number of hemopoietic stem cells. Moreover, we observed that BPA in bone-marrow-conditioned medium (BMCM) from patients with severe aplastic anemia increased more than in the BMCM from patients with severe iron deficiency anemia. Therefore, our findings suggest that the enhanced BPA production depends on a decrease in hemopoietic precursors rather than the anemic state.

Regulatory roles of burst-promoting activity (BPA) from bone marrow cells during human regenerating hemopoiesis

To clarify the regulatory roles of burst-promoting activity (BPA) in cases of in vivo erythropoiesis, we examined erythroid progenitors and BPA in 18 patients with a regenerating hemopoiesis following intensive chemotherapy. Marrow erythroid progenitors increased remarkably in these patients. Bone marrow-conditioned medium (BMCM) and sera obtained from these patients revealed high levels of BPA. Serial examination of a typical case showed that BPA in BMCM and sera increased during regenerating hemopoiesis, but decreased when the hemopoiesis stabilized. Adherent cell depletion and treatment with monoclonal antibody (OKM1) reduced BPA production from the bone marrow cells, thereby suggesting that bone marrow macrophages are responsible for the BPA production. Fractionation of pooled BMCM with Amicon Diaflo membranes showed that the BPA was mainly present in the 30,000- to 50,000-dalton fraction. BPA in BMCM was heat labile, inactivated by trypsin and protease, but was not inactivated by neuraminidase. Pooled BMCM did not influence the growth of CFU-E-derived colonies. Our results suggest that to repair disturbed erythropoiesis, bone marrow macrophages produce BPA during regenerating hemopoiesis.

Erythroblast transferrin receptors and transferrin kinetics in iron deficiency and various anemias

To clarify the role of transferrin receptors in cases of altered iron metabolism in clinical pathological conditions, we studied: number of binding sites; affinity; and recycling kinetics of transferrin receptors on human erythroblasts. Since transferrin receptors are mainly present on erythroblasts, the number of surface transferrin receptors was determined by assay of binding of 125I-transferrin and the percentage of erythroblasts in bone marrow mononuclear cells. The number of binding sites on erythroblasts from patients with an iron deficiency anemia was significantly greater than in normal subjects (p less than 0.01). Among those with an aplastic anemia, hemolytic anemia, myelodysplastic syndrome, and polycythemia vera compared to normal subjects, there were no considerable differences in the numbers of binding sites. The dissociation constants (Kd) were measured using Scatchard analysis. The apparent Kd was unchanged (about 10 nmol/L) in patients and normal subjects. The kinetics of endocytosis and exocytosis of 125I-transferrin, examined by acid treatment, revealed no variations in recycling kinetics among the patients and normal subjects. These data suggest that iron uptake is regulated by modulation of the number of surface transferrin receptors, thereby reflecting the iron demand of the erythroblast.

Influence of zopiclone on male reproductivity in rats

The influence of zopiclone, a non-benzodiazepine hypnotic, on male reproductivity and the recovery of the influences were examined in rats since it was found that oral administration of zopiclone to male rats produced sperm death and infertility at doses of 50 mg/kg or more. In the present study, zopiclone was administered orally by gavage at doses of 50 and 250 mg/kg once daily for 6 weeks to male rats of 8 weeks old. The rats were paired with untreated female rats at the end of the 2nd, 4th, and 6th weeks of administration and of the 2nd, 4th, and 6th weeks after termination of the administration. As the results, the copulation rates were 100% in the 50 mg/kg group, but the rate was low in the 250 mg/kg group at the end of the 2nd week of administration. The pregnancy rates of 0% and low motility and morphological abnormalities of the sperm were observed in the zopiclone-treated groups at the end of the 2nd week of administration. In the histological examination of the male reproductive organs, such changes as arrest of spermatogenesis and dilation of the epididymal ducts filled with the sperm were observed in the 250 mg/kg group at the end of the 2nd week of administration. In the recovery observation, the ability to impregnate female rats and the condition of the sperm recovered in the 50 mg/kg group at the end of the 2nd week of recovery. In the most rats of the 250 mg/kg group the ability to impregnate female rats and the condition of the sperm recovered at the end of the 4th and 6th weeks of recovery. However, in some rats of the 250 mg/kg group the ability to impregnate female rats and the condition of the sperm were still not recovered at the end of the 6th week of recovery.

A stimulator of mouse stem cell proliferation produced by human regenerating bone marrow

We examined CFU-S proliferation stimulator, which recruits stem cells in DNA synthesis, in conditioned media prepared from bone marrow cells of patients with regeneration hemopoiesis after chemotherapy induced hypoplasia. This activity was estimated by hydroxyurea sensitivity of CFU-S in mice, under conditions of incubation with human bone marrow conditioned medium (BMCM). We found that CFU-S proliferation stimulator was present to a considerable extent in human regenerating BMCM, but less so in normal BMCM and that the production fluctuated with change of hemopoietic states, in the same patient. This stimulator was heat-labile, trypsin-sensitive and mainly produced by adherent cells. This factor may possibly be involved in regulation of proliferation of stem cells in regenerating bone marrow in humans.

Expression of c-myc oncogene during differentiation of human burst-forming unit, erythroid (BFU-E)

We investigated the serial expression of c-myc oncogene during differentiation of normal human burst-forming unit, erythroid (BFU-E), in vitro, together with the replating efficiency and the expression of transferrin receptors. We found that the c-myc oncogene was expressed in the early progeny of BFU-E and that this expression decreased during erythroid differentiation. This change of the c-myc expression was well correlated to changes in the replating efficiency and the expression of transferrin receptors. These observations indicate that the c-myc oncogene probably has a physiological role in normal human hematopoiesis as well as leukemic hematopoiesis.

Clinical significance of human bone marrow stromal cell colonies in acute leukemias

Human bone marrow-derived fibroblastoid colony-forming cells (CFU-F) and adipocyte colonies in 36 patients with acute leukemia were studied, and were serially analysed at different clinical stages. At untreated stage, CFU-F number in acute lymphoblastic leukemia (ALL) was lower than that in acute non-lymphoblastic leukemia (ANL). In ANLs, CFU-F number in M1 was lower than that in M2. Adipocyte colonies were frequently developed at regenerating and relapsing stages, but rarely at untreated and remission stages. The adipocyte colony formation did not correlate with any of CFU-F number, marrow cellularity nor number of leukemic cells, but might be associated with hemopoietic regeneration. The favorable prognosis was associated with normal CFU-F number and with adipocyte colony formation at regenerating or bottom stage. As adipocytes in marrow samples were completely removed before cultures, adipocyte colony was probably originated from preadipocytes. Thus, our results suggest that adipocyte precursor cells increase in regenerating marrow and that they are essential in active hemopoiesis.

Periodical appearance of erythropoietin-independent erythropoiesis in chronic myelogenous leukemia with cyclic oscillation

A patient with Ph1-positive chronic myelogenous leukemia (chronic phase) had a cyclic oscillation in white blood cells, platelets and percent saturation of transferrin. The cycle comprised about 70 days. The number of circulating granulocyte-macrophage colony-forming units (CFU-GM) oscillated with the same phase, while that of bone marrow CFU-GM and erythroid colony-forming units (CFU-E) oscillated in a reverse phase. At the nadir, we observed an abnormal increase in bone marrow endogenous CFU-E (e-CFU-E). An erythropoietin (Epo) dose-response curve of CFU-E showed a high Epo-sensitivity. Anti-Epo rabbit serum did not inhibit the e-CFU-E colony formation. This indicates that Epo-independent erythropoiesis occurs periodically at the nadir. It is suggested that the interactions between the abnormal stem cell and the hematopoietic regulating system cause cyclic oscillation.

Enhanced myotoxicity and involvement of both type I and II fibers in monensin-tiamulin toxicosis in pigs

Simultaneous administration of monensin and tiamulin to pigs resulted in enhanced myotoxicity. Skeletal muscles of tongue, diaphragm and legs were preferentially affected, whereas the masseter, longissimus thoracis and cardiac muscles, including the left auricle, were spared. Histochemical examination revealed an involvement of both type I and II fibers of skeletal muscles.

Aspiration pneumonia with adenovirus infection in a Japanese macaque (Macaca fuscata fuscata)

Pneumonia with aspiration of foreign bodies and adenovirus infection was identified in a wild Japanese macaque which died 1 month after capture. The adenovirus infection was considered to be secondary in importance to the pneumonia.

Naturally occurring Tyzzer's disease in a clean mouse colony: high mortality with coincidental cardiac lesions

Light and electron microscopic examinations were performed on tissues from 12 young mice which were affected by naturally-occurring Tyzzer's disease. Eight of the 12 mice had cardiac lesions which have not previously been reported in mice and which caused a high mortality. The cardiac lesions were detected in mice which had severe and advanced intestinal lesions which penetrated the deeper mucosa and muscular layer with active regeneration of the mucosal epithelium. Periodical serological tests to monitor the bacterial and viral status of this colony showed that it was free of other agents of murine disease such as mouse hepatitis virus, Corynebacterium kutscheri and Salmonella spp. until the onset of Tyzzer's disease and that no mixed infection occurred at the onset. It is considered that an advanced intestinal lesion is essential for the formation of cardiac lesions in Tyzzer's disease in mice.

Influence of chlorpromazine administered to rat dams in the peripartum and nursing periods on the learning behavior of the second generation

Behavioral teratogenicity of chlorpromazine (CPZ) was studied in rats by observing the spontaneous motor activity level and learning behavior of light-dark discrimination in the second generation. The dams were treated with CPZ from day 17 of gestation to postpartum day 21 at doses of 2 mg/kg sc. once daily in one group and 4 mg/kg sc. twice daily in the other. The activity level of F1 was measured at 6 to 7 weeks of age for 68 hrs by a magnetic field counter. The learning experiments were started at 5 weeks of age in one group and 15 weeks of age in the other on the behaviors of the continuous food reinforcement at the beginning, then the light-dark discrimination, and finally the reversal discrimination learning. As the results, no influence of the CPZ treatment was observed in the activity level and learning behaviors of the continuous food reinforcement and light-dark discrimination. But, in the reversal learning of the light-dark discrimination an impairment or delay was observed in some F1 of the CPZ groups. Thus, the significance of observing reversal learning behavior in the assessment of the behavioral teratogenicity of drugs has been shown.

The morphogenesis of a papillomatous gastric polyp in the crab-eating monkey (Macaca fascicularis)

The histopathology of gastric papillomas in 17 crab-eating monkeys from Indonesia and Malaysia was investigated. The changes in the affected mucosa consisted of papillomatous proliferation with accidental heterotopia, desquamation or necrosis of the epithelium associated with eggs or adults of the small nematode Nochtia nochti, inflammatory cell infiltration and haemorrhage or oedema and fibrosis. The primary pathogenic effect of this parasite was due to its irritant action on the gastric mucosa. Hyper-regeneration, with a downward shift of the proliferating zone in the gastric gland and an inflammatory process, appeared to play a significant role in the morphogenesis of this lesion. It is concluded that the gastric papilloma associated with Nochtia nochti in the monkey is a parasitic inflammatory polyp.