Factors influencing hematopoietic spleen colony formation in irradiated mice. 3. The effect of repetitive irradiation upon proliferative ability of colony-forming cells.

Mice were irradiated repetitively at 6 wk intervals. The proliferative capacity of the hematopoietic stem cell compartment was studied after each irradiation and compared to that of age-matched controls which had been irradiated only once. Hematopoietic proliferation capacity was measured by determining the number of spleen colonies, splenic iron uptake, spleen weight, and volume of packed red cells 10 days after irradiation. 6 wk after the first irradiation, the hematopoietic compartment was apparently supranormal in size for, when such mice were again irradiated, their postirradiation hematopoiesis was in excess of that of the controls. Thereafter, there was a steady decline in regenerative capacity with each sequential irradiation. After the sixth irradiation, the number of spleen colonies and iron uptake were reduced to one-fifth of that of singly irradiated controls. A decline in body weight and an increase in irradiation mortality accompanied the decline in postirradiation hematopoiesis. The degree of measured decline in hematopoietic proliferative ability was less than that observed by other investigators who studied the effect of serial transplantation of cells upon their ability to proliferate. Furthermore, even after the sixth irradiation, a marked stimulation of postirradiation hematopoiesis was induced by bleeding the animals before irradiation.

Factors influencing hematopoietic spleen colony formation in irradiated mice. II. The effect of foreign materials.

Normal dog plasma and serum, human, rat, and Swiss-Webster mouse plasma, phytohemagglutinin, sheep red cells, mumps and influenza vaccine, fibrinogen, and endotoxin injected before irradiation led to an increased number of endogenously derived spleen colonies in irradiated mice. Spleen weight and uptake of radioactive iron and iododeoxyuridine into such spleens were also increased. The relationship between these parameters of splenic hematopoiesis was unchanged by plasma injection suggesting that, while the number of colonies was increased, the composition of individual colonies was unchanged. This conclusion was supported by studies on plethoric mice in which splenic erythropoiesis is abolished. Increased splenic hematopoiesis was accompanied by an increase in the volume of packed red blood cells 10 days after irradiation. The total volume of plasma injected, the number of days of plasma injection preceding irradiation, and the route of administration were all important variables influencing the effect of plasma injections. Crude fractions of human albumin and gamma globulin, cortisol, C57BL (maternal) and DBA (paternal) mouse plasma, and isogeneic plasma were without effect. The ineffectiveness of isogeneic and closely related allogeneic plasma rendered unlikely the hypothesis that this effect represented the presence of homeostatic hematopoietic regulating factors in plasma. The increased hematopoiesis induced with plasma appeared to be limited to the spleen, for increased bone marrow hematopoiesis was not detected. Certain observations suggested that the effect of plasma may not be due to an antigenic or an inflammatory effect. From current observations, it was unclear whether the increased colonies induced by plasma were representative of expansion of the colony-forming cell pool or of increased efficiency of growth of the fraction surviving irradiation.

Factors influencing hematopoietic spleen colony formation in irradiated mice. I. The normal pattern of endogenous colony formation.

Data pertaining to the endogenous mouse spleen colony system, 10 days postirradiation, are presented. The D(o) for visible colonies is 78 R, while that for 6 hr iron uptake over a range of 600-800 R is 50 R. The D(o) for spleen weight is 196 R and that for IUdR uptake is 193 R. These measurements increase with the age of the mouse. Hypertransfusion decreases spleen iron uptake and colony number. DF-(32)P and sodium sulfate-(35)S are not useful indicators of splenic hematopoiesis in this system. Visible hematopoietic colonies in the spleen are not produced by vinblastine, nitrogen mustard, methotrexate, or cyclophosphamide.

Bone marrow colonies: stimulation in vitro by supernatant from incubated human blood cells.

A substance which stimulates growth of granulocytic and mononuclear cell colonies from mouse and human bone marrow was produced by incubated human blood cells. It is resistant to heat and freezing and is not dialyzable. Intact irradiated and unirradiated cells had very little activity, and sonically disrupted cells had no activity. The addition of plasma or sonically disrupted cells to the cell supernatant decreased its activity.

Autonomous erythropoiesis during erythroblastic crisis of chronic myelocytic leukemia.

Two patients with chronic myelocytic leukemia who developed an erythroblastic rather than a myeloblastic phase were studied with respect to whether or not the megaloblastic erythropoiesis was subject to normal control mechanisms. After transfusion, no significant reduction was observed in the percentage of nucleated erythroid precursors or of proerythroblasts in marrow or in blood reticulocytes. In one of the two patients, ferrokinetics and urinary erythropoietin levels were studied and were also compatible with the conclusions that erythropoiesis was autonomous in this rare syndrome. Three patients with clinical pictures compatible with Di Guglielmo's syndrome were studied as controls. As has been reported previously, erythropoiesis in this syndrome appeared to be responsive to normal control mechanisms. These data suggest that these two clinically similar syndromes, erythroblastic crisis of chronic myelocytic leukemia and Di Guglielmo's syndrome may represent qualitatively different defects in hematopoietic stem cells.

Neutrophil kinetics in acute infection.

Neutrophil kinetics of acute experimental infection were studied with diisopropylfluorophosphate-(32)P labeling in 31 dogs inoculated intrabronchially with pneumococci. In vitro neutrophil labeling indicated a rapid transit time through the blood in early infections, with an elevated marginal granulocyte pool sometimes preceding an elevation of the circulating granulocyte pool. 13 hr after infection, the circulating and total blood granulocyte pools were increased but the rate of neutrophil transit through the blood was normal. During the recovery from infection there was a marked prolongation of neutrophil blood transit time, suggesting virtually complete cessation of bone marrow release of neutrophils into the blood. Labeling of neutrophils in vivo indicated an increased rate of emptying of the bone marrow storage pool proportional to the severity of infection as measured by the fever index. The change in the blood ratio of nonsegmented to segmented neutrophils was a much more accurate index of the severity of infection than the blood granulocyte concentration, correlating significantly with the fever index.

Leukokinetic studies. 13. A non-steady-state kinetic evaluation of the mechanism of cortisone-induced granulocytosis.

The mechanism by which adrenocortical steroids induce granulocytosis in man has been investigated using granulocytes labeled with radioactive diisopropylfluorophosphate. After an intravenous injection of 200 mg of cortisol was given to five normal subjects, the mean value for the total blood granulocyte pool increased from 79 to 138 x 10(7) cells per kg of body weight and reflected an increase in the size of both the circulating granulocyte pool and the marginal granulocyte pool. When granulocytes in the circulation were labeled with diisopropylfluorophosphate and granulocytosis was induced later by the intravenous administration of cortisol, the rate of decline of granulocyte specific activity was increased, indicating that the blood pool was being diluted at an accelerated rate by unlabeled cells entering from the bone marrow. The rate of egress of granulocytes from the blood pool to an inflammatory exudate was studied by the "skin window" technique. After the administration of cortisol, there was a mean reduction in the cellularity of induced inflammatory exudates of 75%. However, this reduction in cellularity varied considerably from subject to subject (45-98%). From these studies we can infer that steroids induce an absolute granulocytosis by decreasing the rate of egress of cells from the total blood granulocyte pool as well as by increasing the influx of cells from the bone marrow. By model simulation studies of the non-steady state induced by cortisol injection, it has been possible to quantitate these rate changes. In the present studies cortisol injection resulted in a mean decrease in blood granulocyte egress of 74% (1-99%) and a mean increase in cell inflow of 450% (300-750%).

Hematopoietic stem cells with high proliferative potential. Assay of their concentration in marrow by the frequency and duration of cure of W/Wv mice.

THIS STUDY WAS DESIGNED TO APPROACH TWO PRIMARY QUESTIONS CONCERNING HEMATOPOIETIC STEM CELLS (HSC) IN MICE: what is the concentration of HSC with extensive proliferative potential in marrow, and how long can an HSC continue to function in an intact animal? The assay system was the W/W(v) mouse, a mouse with an inherited HSC defect, reflected in a reduction in all myeloid tissue and most particularly in a macrocytic anemia.A single chromosomally marked HSC will reconstitute the defective hematopoietic system of the W/W(v). The concentration of HSC in normal littermate (+/+) marrow was assayed by limiting dilution calculation using cure of W/W(v) as an end point (correction of anemia and erythrocytes' macrocytosis) and found to be approximately 10/10(5). This is significantly less than spleen colony forming cell (CFU-S) concentration: approximately 220/10(5) in +/+ and ranging from 50 to 270/10(5) in various other studies. Blood values were studied at selected intervals for as long as 26 mo. Of 24 initially cured mice, which were observed for at least 2 yr, 75% remained cured. However, of all cured mice, 17 lost the cure, returning to a macrocytic anemic state. Cured mice had normal numbers of nucleated and granulocytic cells per humerus and a normal concentration of CFU-S. However, cure of secondary W/W(v) recipients by this marrow was inefficient compared with the original +/+ marrow. These studies suggest the CFU-S assay over-estimates extensively proliferating HSC or perhaps does not assay such a cell. A single such HSC can not only cure a W/W(v), but can sustain the cure for 2 yr or more, despite a relative deficit of cells capable of curing other W/W(v). However, the duration of sustained cure may be finite.

Hematopoiesis and aging: IV. Mass and distribution of erythroid marrow in aged mice.

Aged mice are "anemic," i.e., they have a lower hematocrit than young adult mice, but this appears to be a "dilutional" anemia; the red cell mass is normal. Other observations have supported the hypothesis that basal erythropoiesis does not change as mice grow old. In the present study, the percentage of injected 59Fe found in the skeleton and spleen, 59Fe distribution between various bones and bone groups, and the number of nucleated erythroid cells per humerus were studied and the total mass of erythroid precursors was calculated. There was no significant difference in any of these values between mice aged 3-27 months. The variability of 59Fe distribution within various skeletal parts was no greater in aged than in young mice. Thus, these data further strengthen the case for normal basal rates of erythropoiesis in aged mice.

Modulation of hematopoiesis and survival after high-dose chemotherapy or radiotherapy: review and discussion of possible mechanisms.

This paper reviews ways by which growth of transplanted or surviving hematopoietic stem cells might be enhanced to improve survival in the case of autologous marrow transplantation. Most of the treatments known to have such effects have been used in isologous mouse models and improve animal survival by enhancing hematopoietic recovery after high doses of whole body irradiation or chemotherapy. Although some of these were studied 20 years ago, the use of such treatments in man has awaited the realization that some disseminated cancer can only be eliminated by use of various treatments where hematopoietic damage is the limiting factor. Although increasing the number of transplanted pluripotent stem cells is the most certain way to hasten return of needed blood cells in transplant patients, several of the treatments listed in the paper have growth enhancing effects on both surviving host stem cells and transplanted cells. There are recent studies which indicate that such priming treatments may also be effective in other normal tissues such as gut and bladder epithelium. At least one study in man has intentionally applied this approach with the expected benefit and others may have done so inadvertently. Much work remains to find new combinations to select the best priming treatments and intervals in man and to determine whether or not such treatments are effective against tumors.

Response of hepatic hematopoiesis to whole body irradiation.

Extensive hepatic erythropoiesis, granulocytopoiesis and megakaryocytopoiesis occur in adult mice given methylcellulose (MC). This appears to be a compensatory response to MC induced hemolytic anemia and thrombocytopenia. The present study was undertaken to evaluate the effects of whole body irradiation (WBI) upon established hepatic hematopoiesis (HH) as well as its effect when given before the induction of HH. Established hepatic erythroid and granulocytic foci were significantly decreased 24 hours after 100 or 300 rads. The DO for erythroid and granulocytic foci was 107 +/- 10 rads and 95 +/- 20 rads respectively, similar to those reported for murine marrow and spleen cell CFUS. Megakaryocytes were more radioresistant, gradually declining over 7 days to 50% of control values following 100 rads and with a DO of 347 +/- 7 rads; suggesting a differential radiation sensitivity compared to erythroid and granulocytic foci. WBI, 100 and 300 rads, given before MC failed to prevent subsequent development of HH although both marrow and spleen responses were reduced. Hepatic granulocytic foci and marrow peroxidase positive cells were reduced by such treatment while erythroid and megakaryocytic foci were similar to controls. This suggests that irradiation damaged stem cells responded to MC with increased erythropoiesis and megakaryocytopoiesis at the expense of granulopoiesis.

The effect of syngeneic marrow injection upon recovery in sub- and near-lethally irradiated mice.

Mice were given sub-lethal (200-600 cGy) or near-lethal (800 cGy) whole body irradiation and the effect of injecting syngeneic marrow on subsequent hematopoietic recovery was studied. Marrow cell injection enhanced erythropoietic recovery after sub-lethal irradiation as reflected in hematocrit values and rate of appearance of 59Fe-labeled red cells in blood. However, this enhanced erythropoiesis was only seen in the spleen, and 59Fe uptake in marrow was reduced. When the irradiation dose was kept constant and the marrow dose increased from 10(5) to 10(6) to 10(7) cells, there was a somewhat erratic increase in spleen 59Fe and a decrease in marrow 59Fe uptake. When marrow cell number was kept constant and the dose of irradiation was increased from 200 to 400 to 600 to 800 cGy, there was an exponential increase in spleen 59Fe uptake but the marrow 59Fe uptake changed from depressed after lower doses to increased after 800 cGy. Cell injection after sub-lethal irradiation did not increase or decrease granulocytopoiesis. Injection of irradiated marrow cells also reduced marrow erythropoiesis and this was evident after both sub- and near-lethal irradiation. However, injection of irradiated cells did not increase splenic erythropoiesis. Following splenectomy, the depressed marrow erythropoiesis attending injection of viable cells was virtually eliminated but no increase was seen. These data suggest that the injection of autologous or syngeneic marrow may not be effective as a means of accelerating hematopoietic recovery after irradiation unless near-lethal or lethal dose have been received.

Transplantation of chromosomally marked syngeneic marrow cells into mice not subjected to hematopoietic stem cell depletion.

The percentage of donor-host chimerism was determined 4-6 weeks or six months after injection of normal bone marrow cells into normal syngeneic or coisogeneic recipient mice. Donor-recipient pairs had chromosome markers that provided easy identification of metaphase cells. The percentage of donor cells in marrow or spleen ranged from 0 to 16% and this percentage was independent of the age of recipient or attempts to stimulate hematopoiesis in donor and/or host mice. In adult C57BL/6 mice there was a roughly linear dose-response relationship between cell dose and percentage of chimerism. There was no apparent dose-response relationship for AKR mice. The percentage of donor cells in the spleen was correlated to that seen in the marrow of recipients. Neonatal mice given the same intraperitoneal marrow cell dose as weanlings, but a larger number of cells relative to their own marrow mass, did not show a larger percentage of chimerism than weanlings. Similarly, weanlings given the same intravenous dose as adults showed no greater degree of chimerism than adults. Temporary anemia, induced by bleeding donors prior to cell collection, or more chronic hemopoietic stimulus (produced by injecting recipients with phenylhydrazine prior to cell injection with subsequent bleeding at intervals) did not result in an increased percentage of chimerism. These results indicate that there are "empty" sites in bone marrow of normal mice in which injected hematopoietic stem cells can lodge and grow.

Effect of rabbit antimouse brain serum on marrow cells capable of curing W/Wv mice.

The W/Wv mouse has a recessively inherited defect in hematopoietic stem cells (HSC) but can be cured of its hematopoietic abnormalities by infusion of marrow from a co-isogeneic, +/+ mouse. The "curative" cell for the W/Wv is thought to be a subcompartment of the HSC that is capable of forming hematopoietic spleen colonies (CFU-S) in irradiated mice. The curative HSC must have a very high proliferative potential and it is known that HSC with variable degrees of proliferative potential are found within the CFU-S compartment. Rabbit antimouse brain serum (RAMBS) was used to treat +/+ marrow and its effect upon CFU-S and upon curative cells was compared with the effect of normal rabbit serum (NRS) or of sham treatment. CFU-S were reduced to 70%-79% of control by NRS and to 8%-9% by RAMBS. Curative cells for the W/Wv were not detectably reduced by NRS; they were reduced by RAMBS, but to only approximately 20%-30% of control. Thus, it appeared to a certain degree that RAMBS spared HSC with a high proliferative potential when compared with its effect on the entire CFU-S compartment.

Granulocytic colonies on macrophage-coated cellulose acetate membranes (CAM) in S1/S1dmice.

The kinetics of formation of granulocytic colonies on macrophage-coated cellulose acetate membranes (CAM) were investigated in Sl/Sld mice, which have a genetic defect in their hematopoietic microenvironment. CAM were left in the peritoneal cavity of mice for 7 days to become coated with peritoneal cells. The mice were then sublethally irradiated to suppress endogenously derived granulocytic colonies, and bone marrow cells were injected i.p. within 1--2 hr irradiation. During the next 7 days, peroxidase-positive granulocytic colonies appeared on CAM. The number of colonies on CAM in Sl/Sld mice at 7 days was consistently less than that from littermate +/+ mice. Since it appeared that the CAM in the Sl/Sld provided an inferior microenvironment to that of the +/+, the effect of raising a CAM in one genotype and transferring it to another was investigated. CAM raised in +/+ or in Sl/Sld were transferred to an irradiated +/+ or Sl/Sld following which cells were injected into the secondary host and colonies determined subsequently. The number of granulocytic colonies on CAM was influenced primarily by the type of secondary host. Colony number was consistently less in the secondary Sl/Sld host than in the +/+ host whether the primary host was a Sl/Sld or a +/+. These observations confirm the concept of a microenvironmental defect in Sl/Sld mice. In addition, the studies indicate that the microenvironment on a CAM can be modified by a secondary host and suggest that "remodeling" of CAM may be a continuous, kinetic process.

The hematopoietic effects of lithium.

The observation that patients treated with Li for manic-depressive illnesses develop an associated leukocytosis has led to a series of experimental and clinical studies of the hematopoietic effects of this simple molecule. Increases in blood neutrophils, eosinophils and perhaps monocytes are observed routinely when persons with an apparently normal hematopoietic system are exposed to "therapeutic" doses of the drug. Blood platelets tend to be increased, but lymphocytes and erythrocytes are unaffected. Neutrophilia reflects a true increase in the total number of mature neutrophils in all body compartments and is due to increased production. Neutrophil function generally is unaffected by Li. In man or in other mammals, certain classes of hematopoietic stem cells are increased by Li administration. Extensive studies of the effect of Li have been carried out in cultures of cells producing colonies of neutrophils and macrophages (CFUNM) in semisolid media. The colony-forming cell itself is little affected by Li. Cells which produce the factor essential for production of normal CFUNM (CSF) are stimulated to produce more CSF by the presence of Li. Studies of changes in vivo in CSF levels yield somewhat conflicting results; serum CSF being increased in some but not in others. Thus, it is not clear if the effect of Li on cell production in vivo reflects a direct effect on granulocytic precursors, including stem cells, or is mediated by stimulation of a feed-back loop (or both). A number of trials of Li therapy designed to modify induced neutropenia or to correct existing neutropenia are reviewed. Although many of these are very difficult to interpret, there is some reason to be optimistic concerning an eventual role for Li therapy of certain diseases associated with hematologic abnormalities.

The pathogenesis and clinical patterns of blastic crisis of chronic myeloid leukemia.

Blast crisis terminates the life of the majority (approximately 80%) of patients with CML. The time of its onset appears to be a random phenomenon, varying from a probable coincidence occurrence with the onset of CML to more than a decade after onset of the chronic phase. In most patients the diagnosis is obvious as very immature cells are found to be the predominant cell in blood and marrow. However, in some, the onset is fairly subtle and the diagnosis of the syndrome will be dependent upon ancillary clinical and laboratory clues supplementing morphologic appearance of the blood and bone marrow. The same spectrum of morphological cell types is observed in blast crisis as is observed in acute myeloid leukemia. The predominant cells usually are myeloblasts and promyelocytes but may be immature monocytes, myelomonocytes, proerythroblasts, or immature megakaryocytes. These and other findings imply that the defect resides in the pluripotent hematopoietic stem cell. It is possible, but by no means proven, that lymphoblastic conversion also may occur. Therapy of blast crisis is quite unsatisfactory but clearly is of benefit in some patients.

Fate of a ferrous sulfate prescription.

Prescriptions for ferrous sulfate, 300 mg, were filled with eight different preparations by 15 pharmacies. Only three types of pills had a reasonably rapid dissolution time in acid media and these were all obtained from university-associated pharmacies. Some form of "slow release" or "enteric coat" feature was present in the pills and capsule supplied by private pharmacies and the Veterans Administration Hospital pharmacy. Adding the phrase "not enteric-coated" to the prescription effected no change in the type of pill supplied. Prices were highly variable, even for the same preparation, and although all generic pills were cheaper than brand-name pills, the "supermarket" type pharmacies charged as much or more for the pills as individually owned pharmacies.

A syndrome resembling idiopathic thrombocytopenic purpura in 10 patients with diverse forms of cancer.

Ten patients with diverse forms of carcinoma (six patients) and of cancer in the lymphoid system (four patients) presented with or subsequently had a syndrome resembling idiopathic thrombocytopenic purpura (ITP). These patients were older than patients who had ITP alone. ITP was coincident with a diagnosis of cancer (three patients), preceded a diagnosis of cancer (three patients) or followed a diagnosis of cancer (four patients). No patients responded to steroid therapy permanently. Therefore, the course of our patients was fairly typical of ITP in the adult. Since we found nine patients with cancer in a survey of 52 consecutive patients with ITP in the adult population admitted to one hospital, this diagnosis may be missed with some frequency; the development of thrombocytopenia being attributed to other causes.

Cytobiologic and clinical aspects in a patient with chronic neutrophilic leukemia after thorotrast exposure.

A patient with fairly typical chronic neutrophilic leukemia, as represented by some two dozen such reported cases, had been given Thorotrast more than 20 years before. Typical myeloblastic crisis developed with remarkable terminal leukocytosis. Mature blood neutrophils had normal function with respect to phagocytosis, bacterial killing, metabolic activation, and chemotactic response. The number of cells producing colonies of neutrophils and monocytes in in vitro semisolid cultures was normal in the blood and increased in marrow. Colony size was smaller than is usually observed in normal patients or in typical patients with chronic myeloid leukemia. Termination in blast crisis, also seen in a few other patients with chronic neutrophilic leukemia, indicates that this is indeed a form of leukemia and not a "leukemoid" reaction of obscure cause. The differential diagnosis of extreme neutrophilia is discussed.