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PubMed1986

Stimulation of persisting colonies in agar cultures by sera from patients with CML and AML.

Cord plasma contains colony-stimulating activity (CSA) which stimulates the in vitro clonal growth of neutrophils, eosinophils, macrophages, erythrocytes, and persisting mast cells in semisolid cultures. Analysis of day 35 colonies in agar cultures was found to be a suitable means of demonstrating this activity and discriminating between it and granulocyte-macrophage colony-stimulating factor (GM-CSF). Serum (10%) from patients with acute and chronic myeloid leukemia (AML and CML) was added to normal human bone marrow cultures to search for similar activity in these patient's serum. Although the number of colonies on day 12 (predominantly neutrophils and macrophages) was not significantly different from the number of colonies in cultures containing normal serum, the number of colonies increased 500% in cultures containing CML serum on day 35. Serum from patients with AML during regeneration also stimulated an increased number of colonies on day 35. Although both eosinophil and mast cell colonies were still present on day 35, only mast cell colonies persisted for 150 days. On day 35, cultures containing 10% CML serum contained predominantly eosinophil colonies (84%), whereas cultures containing AML serum contained predominantly mast cell colonies (76%). Although serum contains various CSFs, the specific factor which stimulates persisting mast cell colonies may be the human equivalent of murine persisting (P) cell-stimulating factor (Multi-CSF).

Agar↗

PubMed1993

Recombinant human stem cell factor enhances myeloid colony growth from human peripheral blood progenitors.

Peripheral blood hematopoietic progenitors (PBHP) are capable of colony growth in vitro. The effect of stem cell factor (SCF), interleukin-6 (IL-6), and basic fibroblast growth factor (bFGF) on myeloid colony proliferation of PBHP was determined. PBHP purified by positive selection with CD34-specific antibody were plated in semisolid agarose with reported plateau doses of interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and granulocyte colony-stimulating factor (G-CSF) to enhance myeloid colony growth. Experiments then were done to examine colony growth in response to SCF or with SCF and bFGF and/or IL6. SCF alone in the absence of any other growth factors did not support colony growth. SCF at a determined optimum concentration of 100 ng/mL added to the combination of IL-3, GM-CSF, and G-CSF enhanced colony growth and size relative to proliferation in response to the latter three factors alone (from 78 to 188 total colonies/10(4) PBHP plated and from 10 to 93 large [> 200 cells] colonies/10(4) PBHP plated). Furthermore, addition of bFGF and/or IL-6 to the combination of optimum concentrations of SCF, IL-3, GM-CSF, and G-CSF further enhanced colony number and size in a dose-dependent fashion. Using the optimum combination of all growth factors, we determined that the number of myeloid colony-forming PBHP in whole blood was similar between individuals at about three colonies per milliliter whole blood. We conclude that progenitors capable of responding to the early-acting growth factor, SCF, are represented in PBHP and that the number of circulating myeloid colony-forming PBHP is likely a regulated parameter that may have an important biologic function.

Antigens, CD↗

PubMed1983

Proliferative kinetics and differentiation of murine blast cell colonies in culture: evidence for variable G0 periods and constant doubling rates of early pluripotent hemopoietic progenitors.

Several investigators have described hemopoietic colonies expressing multi-lineage differentiation in culture. We recently identified a class of murine hemopoietic progenitors which form blast cell colonies with very high replating efficiencies. In order to clarify further the relationship between progenitors for blast cell colonies and progenitors for the multilineage hemopoietic colonies in culture, we carried out analyses of kinetic and differentiation properties of murine blast cell colonies. Serial observations of the development of blast cell colonies into multilineage (and single lineage) colonies in cultures of spleen cells obtained from 5-fluorouracil (5-FU)-treated mice confirmed the transitional nature of the murine blast cell colonies. The data also suggested that the early pluripotent progenitors are in G0 for variable periods, and that when triggered into cell cycle, they proliferate at relatively constant doubling rates during the early stages of differentiation. The notion that some of the pluripotent progenitors are in G0 was also supported by long-term thymidine suicide studies in which spleen cells were exposed to 3H-thymidine with high specific activity for 5 days in culture, washed, and assayed for surviving progenitors. Comparison of replating abilities of day-7 and day-16 blast cell colonies from normal as well as 5-FU-treated mice indicated that some of the day-7 blast cell colonies are derived from maturer populations of progenitors which are sensitive to 5-FU. In contrast, progenitors for the day-16 blast cell colonies are dormant in cell cycle and were not affected by 5-FU treatment. Previously we reported that progenitors for day-16 blast cell colonies have a significant capacity for self-renewal. These observations suggest the hypothesis that the capability for self-renewal is accompanied by long periods of G0, and that once commitment to differentiation takes place, then active cell division occurs.

Animals↗

PubMed1989

Murine B-cell stimulatory factor-1 (BSF-1)/interleukin-4 (IL-4) is a multilineage colony-stimulating factor that acts directly on primitive hemopoietic progenitors.

Interleukin-4 (IL-4), which was originally identified as a B-cell growth factor, has been shown to produce diverse effects on hemopoietic progenitors. The present study investigated the effects of purified recombinant murine IL-4 on early hemopoetic progenitors in methylcellulose culture. IL-4 supported the formation of blast cell colonies and small granulocyte/macrophage (GM) colonies in cultures of marrow and spleen cells of normal mice as well as spleen cells of mice treated with 150 mg/kg 5-fluorouracil (5-FU) 4 days earlier. When the blast cell colonies were individually picked and replated in cultures containing WEHI-3 conditioned medium and erythropoietin (Ep), a variety of colonies were seen, including mixed erythroid colonies, indicating the multipotent nature of the blast cell colonies supported by IL-4. To test whether or not IL-4 affects multipotent progenitors directly, we replated pooled blast cells in cultures under varying conditions. In the presence of Ep, both IL-3 and IL-4 supported a similar number of granulocyte/erythrocyte/macrophage/megakaryocyte (GEMM) colonies. However, the number of GM colonies supported by IL-4 was significantly smaller than that supported by IL-3. When colony-supporting abilities of IL-4 and IL-3 were compared using day-4 post-5-FU spleen and day-2 post-5-FU marrow cells, IL-4 supported the formation of fewer blast cell colonies than did IL-3. IL-4 and IL-6 revealed synergy in support of colony formation from day 2 post-5-FU marrow cells. These results indicate that murine IL-4 is another direct-acting multilineage colony-stimulating factor (multi-CSF), similar to IL-3, that acts on primitive hemopoietic progenitors.

Animals↗

PubMed2006

Investigating the heterogeneity of cell growth in microbial colonies by FTIR microspectroscopy.

Microorganisms rarely occur as individual cells in nature and are, instead, organized in complex multicellular communities such as colonies, fruiting bodies, or biofilms. Interest in the natural microbial life-style has increased during the last decade and a whole plethora of techniques has been used to gain insight into the development, structure and composition of diverse microbial communities. We have developed a technique for investigating the spatial heterogeneity of microbial growth in macro-colonies which essentially entails excision of the colonies with the underlying agar, freezing and subsequent cryotoming of the colonies, then FTIR microspectroscopic mapping of the cryosections. Colonies from Legionella, Bacillus, and Candida strains were chosen as model systems of multi-cellular communities to evaluate the technique. The results obtained indicate pronounced cell population heterogeneity even in relatively young colonies cultivated under laboratory conditions. Spectral data obtained from different positions within, e.g., a colony of Legionella bozemanii 120 h old indicated that levels of the storage material poly-beta-hydroxybutyric acid were significantly higher in cells at the surface of the colonies than in those growing at the bottom next to the agar surface. Similarly, in a 24-h-old macro-colony of Bacillus megaterium significantly more of the capsular compound polyglutamic acid was detected in upper layers than in deeper layers of the colony. Results demonstrate that FTIR microspectroscopy can be an useful tool for investigation of the spatial heterogeneity of cell growth within microbial macro-colonies. It is suggested that the method also can be adapted to the analysis of more complex multicellular communities, for example fruiting bodies, biofilms, or colonies growing under natural conditions.

Bacterial Physiological Phenomena↗

PubMed1991

Direct proliferative actions of stem cell factor on murine bone marrow cells in vitro: effects of combination with colony-stimulating factors.

Stem cell factor (SCF), the ligand for the c-kit protooncogene product, was able to stimulate blast cell and granulocytic colony formation by precursors from normal murine bone marrow. The blast cell colonies contained a high content of progenitor cells able to form macrophage and/or granulocyte colonies. Clone transfer studies, the secondary culture of colony cells, and the culture of populations freed of accessory cells all indicated a direct proliferative action of SCF. SCF receptors were present in high numbers on blast cells and in lower numbers on immature granulocytic, monocytic, and eosinophilic cells. Combination of SCF with granulocyte, granulocyte-macrophage, or multipotential colony-stimulating factors, but not macrophage colony-stimulating factor, resulted in enhancement of colony size. Granulocyte colony-stimulating factor enhanced cell proliferation initiated by SCF, but not vice-versa, and resulted in a 10-fold increase in colony cell numbers and a 7-fold increase in progenitor cells in blast colonies. No evidence was obtained that SCF, alone or in combination with granulocyte colony-stimulating factor, could stimulate self-generation by blast colony-forming cells.

Animals↗

PubMed1993

Megakaryocyte and erythroid colony formation in essential thrombocythaemia and reactive thrombocytosis: diagnostic value and correlation to complications.

Megakaryocyte and erythroid colony formation in vitro by progenitors from the bone marrow and/or blood was studied in 61 patients with essential thrombocythaemia (ET) and 22 patients with reactive thrombocytosis (RT) using the methyl cellulose assay. 47 (77%) of the patients with ET showed megakaryocyte and/or erythroid spontaneous colony formation while 14 (23%) patients did not have any kind of spontaneous colonies. Spontaneous megakaryocyte colony formation was seen in 42 (69%) of the patients and 36 (59%) ET patients showed spontaneous erythroid growth. 31 patients had both types of spontaneous colonies. 11 patients showed only spontaneous megakaryocyte colony formation, and five patients only spontaneous erythroid growth. None of the patients with RT or of the normal controls showed either type of spontaneous growth. Neither the presence of spontaneous megakaryocyte colony formation nor the number of spontaneous colonies correlated with the platelet count. Patients with spontaneous megakaryocyte growth had significantly more often thromboembolic or haemorrhagic problems than those without spontaneous colony formation. In conclusion, it was found that a great majority of patients with ET but none of those with RT grow spontaneous megakaryocyte and/or erythroid colonies. Spontaneous colony formation is strong evidence for a myeloproliferative disorder. The presence of spontaneous colony growth is associated with an increased risk of thromboembolic or haemorrhagic complications regardless of the platelet count, particularly among young patients.

Adult↗

PubMed1998

Development of a colony lift immunoassay to facilitate rapid detection and quantification of Escherichia coli O157:H7 from agar plates and filter monitor membranes.

E. coli O157:H7 is a food-borne adulterant that can cause hemorrhagic ulcerative colitis and hemolytic uremic syndrome. Faced with an increasing risk of foods contaminated with E. coli O157:H7, food safety officials are seeking improved methods to detect and isolate E. coli O157:H7 in hazard analysis and critical control point systems in meat- and poultry-processing plants. A colony lift immunoassay was developed to facilitate the positive identification and quantification of E. coli O157:H7 by incorporating a simple colony lift enzyme-linked immunosorbent assay with filter monitors and traditional culture methods. Polyvinylidene difluoride (PVDF) membranes (Millipore, Bedford, Mass.) were prewet with methanol and were used to make replicates of every bacterial colony on agar plates or filter monitor membranes that were then reincubated for 15 to 18 h at 36 +/- 1 degree C, during which the colonies not only remained viable but were reestablished. The membranes were dried, blocked with blocking buffer (Kirkegaard and Perry Laboratories [KPL], Gaithersburg, Md.), and exposed for 7 min to an affinity-purified horseradish peroxidase-labeled goat anti-E. coli O157 antibody (KPL). The membranes were washed, exposed to a 3,3',5,5'-tetramethylbenzidine membrane substrate (TMB; KPL) or aminoethyl carbazole (AEC; Sigma Chemical Co., St. Louis, Mo.), rinsed in deionized water, and air dried. Colonies of E. coli O157:H7 were identified by either a blue (via TMB) or a red (via AEC) color reaction. The colored spots on the PVDF lift membrane were then matched to their respective parent colonies on the agar plates or filter monitor membranes. The colony lift immunoassay was tested with a wide range of genera in the family Enterobacteriaceae as well as different serotypes within the E. coli genus. The colony lift immunoassay provided a simple, rapid, and accurate method for confirming the presence of E. coli O157:H7 colonies isolated on filter monitors or spread plates by traditional culture methods. An advantage of using the colony lift immunoassay is the ability to test every colony serologically on an agar plate or filter monitor membrane simultaneously for the presence of the E. coli O157 antigen. This colony lift immunoassay has recently been successfully incorporated into a rapid-detection, isolation, and quantification system for E. coli O157:H7, developed in our laboratories for retail meat sampling.

Agar↗

PubMed2001

Changes in epidermal radiosensitivity with time associated with increased colony numbers.

Epidermal clonogenic cell survival and colony formation following irradiation were investigated and related to radiosensitivity. A rapid in vivo/in vitro assay was developed for the quantification of colonies arising from surviving clonogenic cells in pig epidermis after irradiation. Bromodeoxyuridine (BrdU)-labelled cells in full thickness epidermal sheets were visualized using standard immunohistochemistry. In unirradiated skin, approximately 900 BrdU-positive cells mm(-2) were counted. In a time sequence experiment, BrdU-positive cell numbers increased from an average of 900 cells mm(-2) to approximately 1400 cells mm(-2) after BrdU-labelling for 2-24 h. In irradiated skin, colonies containing >/=16 BrdU-positive cells were seen for the first time at days 14/15 after irradiation. The number of these colonies per cm(2) as a function of skin surface dose yielded a cell survival curve with a D(0)-value (+/-SE) of 3.9+/-0.6 Gy. This relatively high D(0)-value is possibly due to a rapid fall off in depth dose distribution for the iridium-192 source and consequently a substantial contribution of hair follicular epithelium to colony formation. At 14/15 days after irradiation, the ED(50) level of 33.6 Gy for the in vivo response of moist desquamation corresponded with 2.7 colonies cm(-2). Surprisingly, the number of colonies increased with time after irradiation with an estimated doubling time of approximately 4 days, while the D(0)-value remained virtually unchanged. This increase in colony numbers could be due to migration of clonogenic cells, to the recruitment of dormant clonogenic cell survivors by elevated levels of cytokines, or to both. Although frequent biopsying caused increased cytokine levels, which had a systemic effect on unirradiated skin, it had no influence on colony formation in irradiated skin. Smaller colonies, containing 4-8 cells or 9-15 cells, were abundant, particularly after higher doses, which resulted in higher D(0)-values. The majority of these small colonies were abortive and did not progress to larger colonies. There was no statistical evidence for significant variations in the interanimal responses.

Analysis of Variance↗

PubMed1990

Effect of culture conditions on in vitro erythroid colony formation in myelodysplastic syndromes.

In vitro colony formation by erythroid progenitors from the bone marrow was studied in 42 patients with a myelodysplastic syndrome using both a standard assay for growing erythroid colonies and an assay designed for growing megakaryocyte colonies. In the standard assay 5 patients had normal numbers of erythroid burst-forming unit (BFU-E) colonies, 8 showed reduced numbers of colonies, and 29 patients had no colony formation. Six patients with markedly reduced numbers of erythroid colonies or no colonies at all in the standard assay showed normal or increased numbers of erythroid colonies in the megakaryocyte assay. In three of these patients the erythroid colony morphology was normal, whereas the other three showed abundant diffuse growth of erythroid subclusters with no normal colonies. In the other patients, the erythroid culture results were similar in both assays. These results indicate that the impairment of erythroid colony growth seen in most patients with a myelodysplastic syndrome is, at least in a number of patients, not due to reduced numbers of erythroid progenitors but to unusual milieu requirements of abnormal progenitors.

Bone Marrow↗

PubMed1990

Relationship between cells forming colonies in diffusion chambers in vivo (CFU-D) and cells with high proliferative potential in vitro (HPP-CFC-1 and -2).

In vivo diffusion chambers implanted in normal mice after 5 days of bone marrow cell culture contained precursor cells that in the presence of recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF), interleukin 3 (IL-3), or colony-stimulating factor 1 (CSF-1), alone or in combination, formed both small and large (high proliferative potential colony-forming cells, HPP-CFC) macrophage-containing colonies in vitro. Synergistic factor from serum-free 5637 cell-conditioned medium (SF5637) enhanced HPP-CFC colony growth only in cultures containing CSF-1. Higher numbers of CSF-1- plus IL-3-responsive colony-forming cells (HPP-CFC-2) were detected in diffusion chamber colony-forming unit (CFU-D) colonies than in intercolony areas, suggesting that they were derived from cells that give rise to the diffusion chamber colony. Further study demonstrated that CFU-D colonies contained cells that formed large macrophage-containing colonies (HPP-CFC-1) in CSF-1- plus SF5637-containing cultures. These findings suggest that single cells (CFU-D) forming colonies in diffusion chambers in mice can give rise to both HPP-CFC-1 and to cells probably representing their progeny, HPP-CFC-2.

Animals↗

PubMed1977

Purification and properties of colony-stimulating factor from mouse lung-conditioned medium.

Colony-stimulating factor, which specifically stimulates mouse bone marrow cells to proliferate in vitro and generate colonies of granulocytes, or macrophages, or both, was purified 3500-fold from mouse lung-conditioned medium. Analysis by discontinuous polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate indicated that there was a single protein component. All of the colony-stimulating activity was coincident with the protein band. The molecular weight of colony-stimulating factor estimated by gel filtration was approximately 29,000 and by electrophoresis approximately 23,000. The specific activity of purified colony-stimulating factor from mouse lung-conditioned medium bound to concanavalin A-Sapharose, indicating that it is a glycoprotein. The small percentage of colony-stimulating factor in mouse lung-conditioned medium which did not bind to concanavalin A-Sepharose appeared to represent molecules which lacked the carbohydrate moieties required for binding to this lectin. It was necessary to include low concentrations (less than 0.01%, v/v) of polymers such as gelatin and polyethylene glycol, or nonionic detergents such as Triton X-100, in all of the buffers used throughout the purification scheme, otherwise colony-stimulating factor was lost from solution. At high concentrations (greater than 20 mug/ml) the factor stimulated the formation of granulocytic, macrophage, and mixed colonies from C57BL mouse bone marrow cells. As the concentration of purified colony-stimulating factor was decreased, the frequency of colonies containing granulocytes also decreased. At low concentrations of colony-stimulating factor (less than 70 pg/ml) only macrophage colonies were stimulated.

Animals↗

PubMed1984

Identification of pure and mixed basophil colonies in culture of human peripheral blood and marrow cells.

We present a colony assay system that allows in situ identification of human basophil/mast cell (basophil) colonies. In methylcellulose culture, in the presence of phytohemagglutinin-leukocyte conditioned media (PHA-LCM), human peripheral blood and bone marrow cells form colonies that can be distinguished by their unique morphological characteristics. Pure basophil colonies are diffuse, small colonies containing small, round, highly refractile cells. These characteristics of the constituent cells led us to the observation that a significant number of basophils are found in combination with eosinophils. The mixed eosinophil/basophil colonies have the distinctive elements of pure eosinophil and pure basophil colonies. Usually, these are diffuse colonies with compact clusters of slightly larger, darker-appearing cells. We also found colonies that contained basophils and neutrophils/monocytes, but this type could not be consistently identified by in situ morphology. Cytochemical analysis confirmed the metachromatic nature of the granules in the basophils. The presence of IgE receptors on the cells was documented by indirect immunofluorescent staining after passive sensitization with purified human IgE. Peripheral blood cells from six healthy volunteers formed 5.7 +/- 1.0 (mean +/- SEM) pure colonies in 2 X 10(5) cells. Cultures of bone marrow cells from patients with various types of anemia had 9.0 +/- 1.5 colonies in 10(5) cells. This is the first description of a colony assay system for in situ identification of a pure population of basophilic granulocytes.

Adult↗

PubMed1981

Growth of normal and tumour haemopoietic cells on glass coverslips in peritoneal cavity of mice. I. Characterization of colonies.

A method for cultivation of normal and tumour haemopoietic progenitor cells on glass coverslips inserted into the peritoneal cavity of mice is described. This technique is a modification of the method proposed by Seki (1973). Intraperitoneal injections of bone marrow cells into syngeneic mice led to the formation of erythroid, myeloid, megakaryocytic, mixed and non-identified colonies on the GC. The greatest number of erythroid colonies was seen on the 3rd-5th day after bone marrow cell injection. The majority (greater than 90%) of the erythroid colonies consisted of 16-80 benzidine-positive cells. When GC-bearing mice were rendered anaemic, the number of erythroid colonies sharply rose, whereas the number of myeloid colonies remained unaltered. The influence of irradiation on haemopoietic colony formation was also investigated. There was a linear relationship between the dose of bone marrow cells injected and the number of haemopoietic colonies formed. Areas of mono- and multilayer growth were observed on the GC. Haemopoietic colonies always occurred on a cell multilayer containing fibroblast-like cells and were never observed on a cell monolayer consisting of macrophage-like cells. When self-maintaining erythroleukaemic cells transformed by Rauscher leukaemia virus (RAL cell line) were cloned, GC tumour colonies formed not only on a multilayer but also on a monolayer. Erythroleukaemic K-2 cells, which were of the same origin as RAL cells and had undergone 500 passages in vitro, did not form colonies on the GC. The nature of haemopoietic progenitor cells (mainly erythroid) forming colonies on GC, the nature of cells providing the haemopoietic inductive microenvironment on GC, the direction of tumour progression in RAL and K-2 cells, as well as some possible applications of the GC colony assay are discussed.

Anemia↗

PubMed1988

Stimulation of murine colony-forming cells with high proliferative potential by the combination of GM-CSF and CSF-1.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has previously been shown to stimulate granulocyte, macrophage, and megakaryocyte lineages to act as an erythroid burst-promoting activity and to stimulate limited replication of spleen colony-forming cells. Here we demonstrate that murine GM-CSF alone or in combination with macrophage colony-stimulating factor (CSF-1) can stimulate colony-forming cells in bone marrow (BM) that have a high proliferative capacity. In cultures of BM from mice treated with 5-fluorouracil (FU) eight days before sampling, GM-CSF alone or in combination with CSF-1 stimulated the formation of large macrophage colonies with diameters greater than 0.5 mm. CSF-1 alone, at 800 units or greater, also stimulated larger colonies; however, these colonies were always less than 1.1 mm in diameter, whereas GM-CSF in combination with CSF-1 stimulated many colonies with diameters between 1 and 4 mm. At all doses of CSF-1 tested, the combination of factors resulted in a synergistic increase in colonies with diameters greater than 1.0 or 2.0 mm. Analysis of the incidence of colony-forming cells in the BM of normal mice and mice 2, 4, 6, and 8 days after FU treatment demonstrated that the progenitor cells stimulated by GM-CSF alone or in combination with CSF-1 were depleted by FU treatment in vivo and regenerated more rapidly than did the macrophage progenitors (M-CFC) stimulated by CSF-1 alone. This is similar to the properties of the previously described high-proliferative potential, colony-forming cell (HPP-CFC) that is responsive to interleukin-3 plus CSF-1 but not the HPP-CFC stimulated by hematopoietin 1 plus CSF-1. These data suggest that GM-CSF plus CSF-1 act synergistically to stimulate a population of progenitor cells that have a high proliferative potential and have properties similar to those of the population of HPP-CFC stimulated by interleukin-3 plus CSF-1.

Animals↗

PubMed1997

Combined olfactory contact with the parent colony and direct contact with nonbreeding animals does not maintain suppression of ovulation in female naked mole-rats (Heterocephalus glaber).

The study investigated the role of odor cues from two naked mole-rat colonies, in conjunction with behavioral cues from nonbreeding colony members, in maintaining suppression of ovulation in subordinate female naked mole-rats isolated from the two parent colonies. Four high ranking nonbreeding female naked mole-rats were removed from their respective parent colonies and singly housed in separate burrow systems. For a 64-day period, the removed females were maintained in daily odor contact with their parent colony by daily rotating soiled bedding material between the parent colony and the burrow systems of removed females. In addition, subsets of nonbreeding animals from the respective parent colony were regularly moved into the burrow systems of removed females for 2-day periods during this 64-day period. Removed females were therefore in continual social contact with subsets of parent colony animals except for the breeding pair. All four removed females exhibited raised levels of urinary progesterone (< 2 ng/mg Cr) indicative of the onset of ovarian function within 3 days of being separated from the parent colony. Removed females exhibited a normal ovulatory cycle with levels of progesterone remaining elevated for 25-35 days (mean concentration of progesterone +/- SEM; 16.2 +/- 2 ng/mg Cr). Initiation of aggression and sexual behavior by removed females increased significantly when they were isolated from the parent colony. The results demonstrated that odor cues from the complete colony in conjunction with behavioral/tactile/vocal cues from the nonbreeding colony members were not the major cues maintaining reproductive suppression in nonbreeding female naked mole-rats. Instead, our results suggest that female reproductive suppression in naked mole-rats is caused by a dominance-related behavioral mechanism requiring direct contact with the breeding female.

Aggression↗

PubMed1981

Abelson leukemia virus induces lymphoid and erythroid colonies in infected fetal cell cultures.

An examination of Abelson murine leukemia virus (A-MuL V)-hematopoietic cell interaction in cultures of fetal tissues reveals that A-MuLV can stimulate the formation of two different types of colonies. One type of colony is white and composed of A-MuLV-transformed lymphoid cells that can develop into established cell lines. These cells are indistinguishable in morphology from typical adult-derived lymphoid transformants. The second type of colony is pink or red and composed of erythroid cells in various stages of differentiation. Although A-MuLV is required to induce the erythroid colonies, and at least some cells in all of these colonies are infected with the virus, no permanently growing cell lines have been established from the cells in these colonies. The frequency of the two types of colonies varies depending upon the tissue and the gestational age of the embryo. Erythroid colonies are found following infection of early and mid gestation tissues while lymphoid colonies are found following infection of mid and late gestation tissues. Mixing experiments indicate that the two types of colonies arise from distinct target cells. Because A-MuLV mutants that are defective for lymphoid cell transformation are also defective for erythroid colony induction, expression of a functional Abelson protein is probably required for colony induction. Thus A-MuLV is capable of stimulating the cells of two distinct hematopoietic lineages. In one case, infection leads to transformation, while in the second, it leads to growth and differentiation. Both types of interaction are mediated, at least in part, by the same A-MuLV gene product, a molecule previously considered to induce transformation in all stably infected cells.

Abelson murine leukemia virus↗

PubMed1993

Lymphoblast colony-culture assay in acute lymphoblastic leukemia: a quantitative approach.

Lymphoblast colony-culture of adult acute lymphoblastic leukemia (ALL) was studied to explore its clinical implication. Among 13 marrow cultures from ALL patients with full-blown disease, 11 developed leukemic colonies. A type of colony, very similar to a lymphoblastic colony and possibly T-cell in origin, could be found in four cultures of the six control marrows. To minimize the difficulty in differentiating a leukemic blast colony and a normal lymphocyte colony, based solely on morphology, a quantitative approach was used. Since both the mean of blast colony count and the mean of blast percentage of leukemic marrow were significantly higher than those of the control group, mean value plus two standard deviations of the control group were defined arbitrarily as upper normal limits. The defined normal range was then used to examine the relationship between results of the cultures and clinical outcome for the ALL patients. Early relapse or incomplete remission following chemotherapy could be predicted in four patients by these quantitative colony-culture assays 0.5-2 months before full-blown disease. The low colony count and low blast percentage in the colony-culture assay of the fifth patient is compatible with the clinical observation of continuous remission. One culture, growing clusters only, had an increased blast percentage; this correlated well with cytogenetic relapse two months later. In summary, the quantitative colony-culture assay could detect morphologically unidentifiable leukemic cells in ALL patients with early relapse or incomplete remission. This quantitative colony-culture system, though not ultrasensitive in the detection of minimal residual leukemic cells, was of potential value as a prognostic assay.

Adolescent↗