Fe59 Uptake Research Articles

FEEDBACK INHIBITORS ON ERYTHROPOIESIS

The RBC level is maintained at a very constant level, regulated through stimulating /ESF/ and inhibiting factors. The regulatory effect of RBC and compounds from RBC has been tested on ESF stimulated exhypoxic polycythemic mice, using the Fe incorporation into RBC as parameter. Both intact and hemolyzed RBC were able to inhibit erythropoiesis. The inhibiting factor did not contain heme. Elemental iron did not reduce the Fe59 uptake. On the contrary, Fe3+= ions rather stimulated ESF induced erythropoiesis, probably due to increased amounts of available iron. Increasing amounts of immature RBC in the testmaterial, reduced the inhibitory effect. An inhibiting factor was liberated into the incubation medium when RBC were incubated for 20 hrs. Mature HBC are able to produce a substance different from heme, with a negative feedback on erythropoiesis. In compensated hemolytic anemias having no elevated ESF levels, the increased erythropoiesis could be explained by hemolysis of the RBC before full maturation.

Erythropoietin release in hypophysectomized, adrenalectomized man.

AbstractErythropoietin (ESF) levels were assayed in 19 female and male patients with intact kidneys with pituitary tumors or following open hypophysectomy or combined hypophysectomy and adrenalectomy for disseminated tumor states. Saline‐injected control mice had 0.38 ± 0.04% Fe59 uptake (ESF). Hypophysectomized, adrenalectomized, castrated females had 2.96 ± 1.24% Fe59 uptake (ESF) with an average peripheral hematocrit of 29.2 vol %. Hypophysectomized, castrated males had 1.59 ± 0.30% Fe59 uptake (ESF) with an average peripheral hematocrit of 30.1 vol %. Thus, absence of the adrenals or functioning anterior pituitary gland does not prevent increased ESF activity. The presence of a pituitary tumor is also not consistently associated with increased ESF activity or release. The role of these endocrine organs in the regulation of ESF release in these states is therefore not essential but more likely represents a normal synergistic mechanism. Elevation of peripheral ESF levels is associated with improvement of anemia after hypophysectomy and may be an additional objective criterion and prognostic indicator of beneficial patient response to hypophysectomy in certain tumor states.

Deficient Fe59 and I-125 deoxyuridine uptake by lympho-hemopoietic cell transplants engaged in homograft reactions.

AbstractErythropoietic activity of spleen cell grafts was measured (Fe59 uptake) in X‐irradiated recipient mice under conditions in which these grafts were engaged in homograft reactions against allogeneic target cells or in graft‐versus‐host reactions. Such Fe59 incorporation was greatly reduced at 7 to 10 days after graft implantation relative to that of control grafts. This reduced erythropoiesis did not occur when the spleen cell graft was immunologically incompetent. Transplantation of bone marrow‐lymph node cell mixtures also resulted in a relative decline in Fe59 uptake, but only when minimal numbers (105 to 106) of marrow cells were injected. The incorporation of I125 UdR in the spleen of irradiated recipients was used to assess cellular proliferation. Incorporation of this label was reduced when measured 7–10 days after implantation of the lympho‐hemopoietic cell graft, but reached a peak at five days—the latter indicating stimulated lymphopoiesis. These data are consistent with the concept of depletion of a pluripotent stem cell pool (limited in size under these experimental conditions) due to excessive and concurrent functional demands for erythropoiesis and lymphopoiesis. An alternative explanation would involve cytotoxic effects on hemopoietic elements present in the milieu of the immunologic reaction.

Comparative effects of cyclophosphamide and total body irradiation on erythropoietin production in rats.

Comparative effects of total body irradiation and cyclophosphamide on erythropoietin production in rats are described. The erythropoietin titers in plasma were determined after the rats had been exposed to hypoxia. The rat plasma to be studied was injected into polycythaemic mice. The Fe59 uptake into the red cells of the polycythaemic mice was used as parameter. The results indicate that neither cyclophosphamide nor radiation in sub‐lethal doses suppresses significantly erythropoietin production.

Inhibition of erythropoietic stimulation by testosterone in polycythemic mice receiving anti-erythropoietin.

SummaryThe injection of testosterone into polycythemic mice produces a small but significant stimulation of erythropoiesis, as measured by Fe59 uptake into the peripheral blood, if the interval bet...

Effects of growth hormone on erythropoiesis in the intact rabbit and the polycythemic mouse.

AbstractElectrical stimulation of the hypothalamic region may produce reticulocytosis and increased red cell mass in intact rabbits (Seip et al. 1961). In order to compare the effect of hypothalamic stimulation on erythropoiesis with the effect of growth hormone (GH), daily GH injections have been given to intact rabbits, and the changes in erythropoiesis have been followed with the same parameters as in the previous study. GH caused a marked peripheral reticulocytosis which was very similar to that following hypothlamic stimulation, and the slope of both curves was similar to those following hypoxia or erythropoietin injections. GH did not, however, cause an increase in ROM. Hemoglobin, erythrocytes and hematocrit decreased, especially during the first days of GH administration, mainly due to hemodilution. The red cell size increased following GH treatment. The plasma erythropoietin levels in the GH treated rabbits were not significantly increased. These findings confirm and extend previous findings of the effect of GH on erythropoiesis, and indicate that the effects of hypothalamic stimulation cannot be explained on the basis of increased GH production alone. The effect of GH on erythropoiesis in the polycythemic mouse was also studied. The results indicate that there is no effect on the stem cell level. Porcine growth hormone did not increase Fe59 uptake into red blood cells in polycythemic mice when given alone or when given in addition to standard erythropoietin. The reticulocyte response to a single dose of standard erythropoietin changed slightly when growth hormone was added.

Spleen weight as a measure of marrow cell growth in irradiated mice.

SummaryC57BL, C3H, C57BL/6, and DBA/2 parental marrow cells were injected at varying doses into lethally irradiated BC3F1 and B6D2F1 mice. Spleen weight in recipients was compared to spleen colony formation and Fe59 uptake. Results showed that increased spleen weight was proportional to formation of increased numbers of splenic nodules and percentage of Fe59 uptake. Data suggest that spleen weight, spleen colony formation, and Fe59 uptake are equally suitable assays, within appropriate limits, for studies on proliferation of marrow cell transplants in irradiated mice. Spleen weight is a useful index of growth for doses of transplanted marrow cells which promote recovery of hematopoietic injury in lethally irradiated mice.

Erythropoiesis in Rats with Acute Uremia and the Effect of Erythropoietin

Abstract The proliferative activity of erythropoietic and other tissues has been studied in normal, nephrectomized and bilateral ureter ligated rats. Forty-eight hours after bilateral nephrectomy, rats showed a significant suppression of DNA synthesis and Fe59 incorporation in the bone marrow and spleen. The administration of erythropoietin prevented this suppression of Fe59 uptake, and produced an increase in splenic DNA synthesis comparable to that noted in the normal, similarly stimulated animal. Bilateral ureter ligation in animals, producing a blood urea nitrogen elevation equal to that induced by nephrectomy, caused no suppression of DNA synthesis in bone marrow or spleen. These latter animals exceeded the normal in their response to erythropoietin administration. Intestinal DNA synthesis was unaffected in uremia produced by nephrectomy or ureter ligation. Thymic proliferative activity was suppressed in uremia induced by either procedure. The observations indicate that acute, severe uremia of relatively short duration does not influence the DNA synthetic activity of all tissues in an adverse fashion. What factors may modify tissue responses are unknown. In the case of erythropoietic organs, such factors seem to originate in the kidney.

Evidence for a Non-Calorigenic Effect of Thyroxin on Erythropoiesis as Judged by Radioiron Utilization.

SummaryThyroxin has been shown to have an effect on erythropoiesis, as judged by Fe59 uptake, which is greater than would be expected from its influence upon oxygen consumption. This non-calorigenic effect on erythropoiesis has been shown in 4 ways—1) by observing a greater percentage increase in Fe59 incorporation than in oxygen consumption in hypophysectomized thyroxin treated rats; 2) by observing an increase in Fe59 uptake in thyroxin treated polycythemic hypophysectomized rats where the increased number of erythrocytes should take care of any erythropoietic response to oxygen need; 3) by finding that thyroxin induced a greater erythropoietic response in thyroidectomized rats than did dinitrophenol even when the latter drug induced a higher oxygen consumption, and 4) by noting that thyroxin treated thyroidectomized polycythemic rats responded by an elevation in Fe59 uptake while dinitrophenol in similar rats had no effect.

MARROW TRANSPLANTATION MEASURED BY UPTAKE OF FE59 BY SPLEEN.

Transplantation of isologous (syngeneic) bone marrow into lethally X-irradiated mice has been quantified in terms of the degree to which the spleen incorporates Fe59. Spleen uptake of Fe59 is linear with bone marrow cell dose and reflects the erythropoietic integrity of the transplanted cells. Parameters of the assay were investigated including X-ray exposure to the recipient, time of assay, Fe59 uptake time and plasma clearance of the isotope. The following protocol was adopted: (C3H x C57BL) F1 male mice are a) exposed to 850 r of X rays, b) injected with bone marrow 24 hr later, c) given Fe59 8 days later, and d) killed 6 hr after isotope injection to obtain spleens for Fe59 analysis. The assay was used to determine radiosensitivity of the erythropoietic compartment of marrow and to determine integrity of marrow cells after short-term culture as a means of studying in vitro recovery from radiation damage. Results showed that the in vitro radiation exposure required to reduce the surviving cells to 37% (D37) was 75 r. Studies of normal cells in short-term culture showed that cell integrity could be maintained for at least 6 hr in Tyrode's solution with calf serum at 22 C but that integrity was reduced after 6 hr at 37 C in all media tested.

Erythropoietic stimulating factor (ESF) as a stimulant of tumor growth.

SummaryFour experimental procedures have been tested for ability to increase ESF concentrations (as measured by Fe59 uptake) and increase tumor growth. It was concluded that ESF extracts prepared by a modified method of Borsook or the method of White and procedures which increase endogenous ESF production (partial hepatectomy and cobalt chloride administration) are capable of stimulating Novikoff hepatoma growth in rats.

Erythrocyte Fe59 Uptake as a Function of Bone Marrow Dose Injected in Lethally Irradiated Mice

AbstractThe relation between bone marrow cell dose and 24-hour erythrocyte Fe59 uptake has been established in lethally irradiated mice. Erythrocyte Fe59 uptake is a function of the dose of bone marrow cells and of the time after irradiation at which Fe59 is injected. By choosing appropriate bone marrow doses and times of Fe59 injection, the range of cell doses between 5 × 105 and 2 × 107 has been explored. The relation between cell dose and Fe59 uptake is linear for Fe59 uptakes between 0 to 30 per cent. The steepest line relating Fe59 uptake to cell dose is that obtained when Fe59 was injected at day 9 and covers the range of 5 X 104 to 5 X 105 cells. The curve obtained when iron is injected on day 5 is much flatter and covers the range of 1 × 106 to 2 × 107 cells. Erythropoiesis stimulating factor (ESF) in doses that stimulate erythrocyte Fe59 uptake in normal mice has no effect in irradiated, bone marrow-treated mice. Homologous marrow is slightly less effective, and rat bone marrow markedly (~ 100 times) less effective in promoting recovery of erythropoieis. The erythrocyte Fe59 uptake of mice preimmunized with homologous or rat marrow before irradiation is much lower than that of nonpreimmunized animals.

Erythropoietin assays using iron59 incorporation into blood and spleen of the polycythemic mouse.

SummaryIncorporation of Fe59 with blood and spleen of transfused polycythemic mice at various intervals has been used to find sensitive assay systems for erythropoietin. Transfusion polycythemia markedly reduces erythropoiesis as judged by low levels of Fe59 uptake into the spleen and into the blood after 16 hours. In polycythemic mice receiving injections of erythropoietin, incorporation of Fe59 is maximal in the spleen at 8 hours and in the blood at 48 hours after injection of the isotope. Incorporation of Fe59 into the blood of the polycythemic mouse 48 hours after giving the isotope was found to be the most sensitive assay when compared to the starved rat assay and other polycythemic mouse assays.

The Relative Biological Effectiveness of 22-Mevp X-Rays, Cobalt-60 Gamma Rays, and 200-Kvcp X-Rays: V. Absorbed Dose to the Bone Marrow in the Rat and the Mouse

Calculations were made of the distribution of dose at the surface of semi-infinite tissue-tissue and bone-tissue layers for spectra of 200-kvcp x rays (0.5 mm Cu + 1 mm Ai, HVL 1.4 mm Cu), Co60 gamma rays, and 22-Mewp x rays. These calculations were applied to physical models of bone marrow cavities in the mouse and the rat, and the results were weighted for the gross distribution of active marrow in the animal. The distribution of functioning marrow across a cavity was assumed to be uniform. It was found that for both animals the bone marrow dose is greater than the soft-tissue dose in all three cases. The relative doses for the rat are 1.07 for 200-kvcp x rays, 1.01 for Co60 gamma rays, and 1.01 for 22-Mewp x rays. The relative doses for the mouse are 1.09, 1.01, and l.01, respectively. This suggests that, if mammalian RBE values are based on bone marrow dose, for both Fe59 uptake and lethality in the rat the RBE for Co60 vs 200-kvcp should be multiplied by 1.06, for 22-Mevp vs 200-kvcp the RBE should be multiplied by 1.06, and for 22-Mevp versus Co60 the RBE should be multiplied by 1.00. For themore » mouse, the RBE values should be multiplied by 1.08, 1.08, and 1.00, respectively.« less

The Relative Biological Effectiveness of 22-Mevp X-Rays, Cobalt-60 Gamma Rays, and 200-Kvcp X-Rays: VII. Summary of Studies for Five Criteria of Effect

The effectiveness of Co60 GAMMA rays and 22-Mevp x rays was found to be the same for five separate biological criteria (yeast LD50, mouse LD50, rat LD50, Fe59 uptake in rats, and chick embryo LD50) within the limits of experimental error. Thus there is presumably no difference in effect due to the pulse rate of the betatron productng the 22-Mevp x rays (except in the unlikely event that a possible energy effect and pulse effect cancel). When all doses are expressed in terms of the absorbed dose to soft tissue the RBE for Co60 gamma rays and 22-Mevp x rays relative to 200- kvcp x rays has an average value of about 0.87, but appears to range between 0.82 and 0.93, depending on the end point. (The mammalian end points studied here appear to have lower RBE values than do the nonmammalian end points.) If the dose in the mammalian cases is expressed as the absorbed dose to bone marrow, the RBE of the supervoltage radiations relative to 200-kvcp x rays for these end points is increased and the sgreement between the RBE values for all the end points becomes very good. Co60 gamma rays and 22-Mevp x rays canmore » then be represented as less effective by a factor of 0.90 plus or minus 0.02 than 200- kvcp x rays for all the biological criteria studied. Co60 gamma rays are to be preferred to x rays in the 200 to 250-kwp region as a standard of comparison , for Rbe experiments. With Co60 Egg rays as the standard, 22- Mewp x rays have an RBE of 1.00, and 200kvcp x rays (absorbed dose to bone marrow) have an RBE of 1.10. No qualitative differences between the three radiations were evident.« less

Effect of chemotherapeutic agents on Friend virusinduced leukemia in mice.

Summary1. A variety of newer and “established” chemotherapeutic agents were tested against FVL in mice. Criteria for effectivity included spleen uptake of Fe59, spleen weight, and mortality. 2. Agents demonstrating both in vivo and in vitro antiviral activity included AB-103, AB-132, and 6-MP. 3. Good correlation appears to exist between Fe59 uptake of the spleen and spleen weights. These 2 parameters correlate with survival in cases where they remain in the normal range. Once they become abnormal, no quantitative relationship exists between survival on one hand, and spleen weights and Fe59 uptake on the other.

Renal clearance of intravenously administered vitamin B12.

SummaryThe erythropoietic stimulating principle present in the filtrate of plasma obtained from anemic rabbits was partially purified by ethanol fractionation. This material was active in increasing Fe59 intake of normal rats and in producing a reticulocytosis and hematocrit elevation in repeatedly injected normal rats. Fe59 uptake was stimulated by as little as 0.08 mg of the fraction representing a concentration of 3,000 fold over that occurring in the plasma.

Effects of plasma erythropoiesis stimulating factor (E.S.F.) at different time intervals after single injection.

SummarySeveral effects of E.S.F. in normal mice were studied as a function of time after injection. The first change was a marked increase of C14 amino acid uptake by globin at 24 hours. This was followed at 48 hours by increase in iron consumption by erythroid tissue, and at 72 hours by an increase of reticulocyte count in peripheral blood as well as by increase in Fe59 and leucine C14 uptake by incubated red cells.

Effect of Friend virus in Swiss and DBA/1 mice on Fe59 uptake.

Summary1. These studies demonstrate that Friend Virus produces in HA/ICR Swiss and DBA/1 mice very soon after infection, a marked increase in selective uptake of Fe59 by the spleen. This selective uptake is not found in other tissues in Friend Virus Disease. 2. Friend Virus Disease characteristically produces a malignant proliferation of splenic reticulum cells, but is further characterized by a progressive elevation of hematocrit and rbc count which is related to splenic involvement in the disease. 3. The DBA/1 strain is shown to be susceptible to Friend Virus to the same magnitude as HA/ICR Swiss mice.We wish to acknowledge the assistance of Dr. Paul Trudel, Andre Bulba, Ruth Deckert, Edward Dywinski, Helen Fox and A. G. Mirand.

Erythropoietic recovery and residual injury in rats exposed repeatedly to x-rays.

Rats exposed repeatedly to 300-r x-rays showed a decrease in Fe59 incorporation which attained its lowest point 48 hours postirradiation. Thereafter iron uptake increased until normal values were measured. This return to normalcy was delayed further with each newly repeated irradiation. On any day during the recovery period Fe59 uptake decreased exponentially with repeated x-irradiations. This decrease is a measure of residual injury to the erythropoietic system. Since, after each repeated irradiation, a reduced amount of Fe59 was incorporated at the beginning of the recovery period, while the rate of recovery was similar, it is postulated that the decrease in radio iron uptake is due to an impairment in the functional capacity of the stem cells to proliferate erythrocytes. A working hypothesis for the calculation of erythrocyte stem cell damage is presented. Although the functional capacity of the stem cells to produce erythrocytes was reduced, the daily red cell turnover was normal. Only when this reduction was below a certain limit did a permanent anemia ensue.