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W Nothdurft

Publications and source records attributed to W Nothdurft.

At least 37 records · Page 2Linked to original sources
PubMed1992

Differences in radiation response between cells in S-phase and non-S-phase cells of the granulocyte/macrophage progenitor (GM-CFC) compartment.

Studies were performed to investigate the radiation response of granulocyte/macrophage progenitor cells from canine bone marrow in different proliferative states, and in which way it will change if the S-phase cells are eliminated from the irradiated populations. To obtain progenitor cells of different proliferative states, bone marrow cell suspensions were kept in liquid cultures for 1 or 3 days in the presence of colony stimulating activity. Radiation dose response curves were determined (a) for the total population of progenitor cells under normal conditions (fraction of cells in S-phase 35%), (b) in a state of rapid cycling (fraction of S-phase cells 53% to 57%), and (c) after sterilization of S-phase cells by pretreatment with 3H-thymidine. The rapidly proliferating progenitor cells showed a strong decrease in their radiosensitivity (D0 = 0.84 Gy) within the first day in suspension culture when compared to the normal population (D0 = 0.50 Gy). The cell populations from which the S-phase cells had been eliminated were found more sensitive than the respective total populations (D0 values in the range from 0.44 Gy to 0.50 Gy). The D0 values for the S-phase cells were between 0.57 Gy and 1.13 Gy depending on the proliferative state of the cell populations. These data indicate that granulocyte/macrophage progenitor cells during progression through the S-phase become less radiosensitive than they are in other phases of the cell cycle.

Animals↗
PubMed1992

Haematological effects of rhGM-CSF in dogs exposed to total-body irradiation with a dose of 2.4 Gy.

It was the specific aim of this study to test the stimulatory effects of recombinant human GM-CSF (rhGM-CSF) on haemopoietic regeneration in dogs which had received total-body irradiation (TBI) with a dose of 2.4 Gy. In normal dogs rhGM-CSF given subcutaneously at 10 microgram/kg per day or 30 microgram/kg per day for 21 days caused strong but transient increases in the peripheral blood neutrophils. The monocyte counts also showed a transient rise during treatment in a dose-dependent fashion, whereas the lymphocyte counts increased only at the higher dose of rhGM-CSF and the platelet counts were transiently depressed during the course of the treatment. In the irradiated animals treatment with rhGM-CSF decreased the severity and shortened the duration of neutropenia but had no significant influence on monocyte or lymphocyte recovery. The granulocyte values showed a characteristic pattern of fluctuations with the first peak occurring at the same time (day 10 to day 13) when the abortive rise was observed in the untreated dogs. In contrast the GM-CFC in the peripheral blood remained depressed during the whole treatment course, similar to the untreated irradiated controls. These results indicate that treatment with GM-CSF can be an effective biological monotherapy for radiation-induced bone marrow failure, but that for higher radiation doses the number of GM-CSF responsive target cells will become a critical determinant of therapeutic efficacy.

Animals↗
PubMed1991

In vitro studies on the radiosensitivity of multipotent hemopoietic progenitors in canine bone marrow.

The in vitro radiation response to 280-kV x-rays (does rate 72 cGy/min) of multipotent hemopoietic progenitor cells, mixed colony-forming units (CFU-mix), from canine bone marrow was assayed and compared to the radiation response characteristics of early erythroid progenitors, erythroid burst-forming units (BFU-E). To improve the colony-forming efficiency, the effect of various bone marrow cell separation techniques on colony formation of both progenitors was examined. The separation of bone marrow aspirates by discontinuous buoyant gradient centrifugation using the lymphocyte separation medium Lymphoprep with a density of 1.070 g/ml allowed the establishment of reproducible survival curves. The survival curves for both progenitors were strictly exponential, and CFU-mix were found to be more radiosensitive (D0 = 12 +/- 2 cGy) than BFU-E (D0 = 16 +/- 2 cGy).

Animals↗
PubMed1990

[The stem cell system of hematopoiesis: physiological and pathophysiological concepts].

It is the purpose of this review to describe the physiological as well as the pathophysiological principles of the hematopoietic stem cell system. The concept of hemopoietic stem cells has a long history which is now understood on the basis of its embryogenesis and after collecting extensive experimental and clinical experience using stem-cell transplantations as a means to restore hematopoietic function of the bone marrow after appropriate conditioning. The hemopoietic stem cells cannot be distinguished by light microscopy from "lymphocytes" considered to be a heterogeneous group of mononuclear cells. These stem cells can respond to specific regulatory factors with specific differentiation and proliferation, and are very radiosensitive and resistant to cryopreservation. The system responds to perturbations in a manner characteristic for feed back regulation and is bound in its physiology to an intact stromal matrix.

Animals↗
PubMed1990

Hematological effects of unilateral and bilateral exposures of dogs to 300-kVp X rays.

Accidental exposures to ionizing radiation from external sources usually result in an inhomogeneous dose distribution rather than a homogeneous total-body irradiation (TBI). To study the hematological effects of an inhomogeneous dose distribution, dogs were unilaterally exposed to a beam of 300 kVp X rays (HVL = 3.8 mm Cu) with their left side directed to the source. The entrance and exit surface doses were 3.8 Gy and 0.9 Gy, respectively. Dose measurements performed in bone marrow spaces of various bones revealed a maximum of 3.1 Gy in the head of the left humerus and a minimum of 0.9 Gy in the right iliac crest. Based on survival for granulocyte-macrophage progenitor cells (GM-CFC) determined in different bone marrow sites 24 h after the exposure, the dose-dependent reduction ranged from 0.44 to 16% of the control values. The regeneration of the GM-CFC compartments in the various bone marrow spaces showed patterns which were independent of each other up to Day 28. Values were normal again at Day 125 after exposure. For comparative purposes, three dogs were exposed bilaterally to achieve a homogeneous dose distribution. They received a TBI of 2.4 Gy, which according to previous calculations should have caused the same systemic damage to the GM-CFC compartment as the unilateral exposure. The peripheral blood cell changes, including the GM-CFC, and the colony stimulating activity in the serum showed a similar pattern for both exposures. These findings support the hypothesis that the overall survival fraction of progenitor cells in the bone marrow is the main determinant of the blood cell changes, independent of the anatomical distribution.

Animals↗
PubMed1989

Hematological effects in dogs after irradiation of the lower part of the body with a single myeloablative dose.

The lower body of dogs, containing approximately 30% of the total bone marrow, was exposed to 300 kV X-rays with a single myeloablative dose of 11.7 Gy, whereas the upper body was shielded by a lead box. The results of the present study are discussed in connection with recently published results obtained after irradiation of the upper body (UBI), containing approximately 70% of the total bone marrow mass. The main findings are as follows: (1) the nadir in the blood concentration of thrombocytes, lymphocytes, and granulocytes strongly depends on the volume of irradiated bone marrow; (2) apart from some quantitative differences, the time-related pattern of changes in the concentration of granulocyte/macrophage progenitor cells (GM-CFC) in irradiated and shielded bone marrow sites is very similar after irradiation of the lower part of the body (LBI) and UBI, i.e. is apparently independent of the relative amount of damaged bone marrow at volumes applied in the present models; (3) the concentration of GM-CFC in the blood after LBI shows a transient increase during the first phase of most rapid bone marrow GM-CFC regeneration, i.e. between day 7 and day 23; the magnitude of this transient increase obviously depends on the fraction of irradiated bone marrow.

Animals↗
PubMed1989

Hematological effects in dogs after sequential irradiation of the upper and lower part of the body with single myeloablative doses.

The compensating mechanisms determining the tolerance of the hemopoietic system to sequential hemibody irradiation (HBI) with large single doses, the regeneration of the irradiated bone marrow and the long-term effects of such treatment were studied in dogs. The main emphasis was laid on the determination of the granulocyte/macrophage progenitor cells (GM-CFC) in the bone marrow and blood. The general pattern of events in the GM-CFC compartment after each exposure was similar. Irradiation with a dose of 11.7 Gy of the upper body (UBI), that involved the abrogation of approximately 70% of the total active marrow, was followed by an immediate increase in the proliferation and differentiation of GM-CFC in the protected bone marrow. Repopulation of the GM-CFC in the irradiated sites most probably due to seeding of hemopoietic cells from the protected marrow already became evident at day 7 after UBI. At day 56 after UBI, when the irradiation of the lower body (LBI) was performed, the GM-CFC had recovered to between 30 and 40% of their pre-treatment values. Despite this incomplete regeneration, the GM-CFC compartment responded to LBI in a similar way as the GM-CFC had in the protected (normal) marrow after UBI, i.e. by an increased proliferation for at least 21 days. Already at day 7, the bone marrow of the iliac crest that had been exposed to LBI showed a considerable number of GM-CFC. Within no more than 370 days all the bone marrow sites irradiated during either the first or the second treatment had regained their normal GM-CFC values.

Animals↗
PubMed1989

In vitro studies of the sensitivity of canine bone-marrow erythroid burst-forming units (BFU-E) and fibroblast colony-forming units (CFU-F) to X-irradiation.

The radiosensitivity of the early erythroid progenitor cells (BFU-E) and the progenitor cells of the stroma (CFU-F) in canine bone marrow was studied under steady-state conditions by in vitro irradiation with 280 kV X-rays. The dose-effect relationship for colony formation was determined for BFU-E obtained from the iliac crest marrow, and for CFU-F in bone marrow collected from the iliac crest and the humerus of adult beagles. The BFU-E were adequately stimulated with serum from lethally irradiated dogs to obtain a source of BPA (burst-promoting activity). The BFU-E proved to be extremely radiosensitive, and the survival curve was exponential (D0 = 15.3 +/- 1.8 cGy). We showed that buffy-coat leukocytes separated from bone marrow leukocytes obtained by aspiration were an optimum source of CFU-F. A curve was fitted to the data obtained for CFU-F obtained from the iliac crest or the humerus, resulting in D0 = 241 +/- 38 cGy and an extrapolation number n = 1.38 +/- 0.62 or D0 = 261 +/- 40 cGy and n = 1.04 +/- 0.42, respectively. According to these findings, and other published data, we conclude that the canine bone marrow BFU-E are presently the most radiosensitive hemopoietic cells detected among all hemopoietic cells of different mammals.

Animals↗
PubMed1988

Blood cell changes after radiation exposure as an indicator for hemopoietic stem cell function.

This paper describes the criteria to be used in the management of persons accidentally exposed to ionizing radiation for predicting whether the stem cell pool damage was reversible or irreversible. This question is of importance. If the damage was reversible, the clinical management may be restricted to symptomatic therapeutic measures (antibiotics, platelet transfusions). If the indicators show that the stem cell damage is irreversible (from a clinical viewpoint) then stem cell transplantation must be considered and performed. A granulocyte computer simulation model is discussed that may be useful in the analysis and evaluation of blood cell regeneration patterns after radiation and transfusion of stem cells from different sources.

Animals↗
PubMed1988

Growth of erythroid burst-forming units (BFU-E) in cultures of canine bone marrow and peripheral blood cells: effect of serum from irradiated dogs.

Erythroid burst-forming units (BFU-E) from canine bone marrow and peripheral blood could be grown in methylcellulose in the presence of an appropriate batch of fetal calf serum (FCS), transferrin, and erythropoietin (Epo). However, improved colony formation (size and number of bursts) was obtained when serum from total body irradiated dogs was present in the culture. This serum, obtained from dogs at day 9 after total body irradiation with a dose of 3.9 Gy, reduced markedly the Epo requirement of BFU-E. Furthermore, it allowed the omission of FCS from the culture medium if cholesterol and bovine serum albumin (BSA) were used as FCS substitutes. BFU-E concentrations were found to be rather different in the peripheral blood and in bone marrow samples from different sites (i.e., iliac crest, sternum, and humerus) of normal beagles. The studies further show that canine bone marrow BFU-E can be cryopreserved in liquid nitrogen.

Animals↗
PubMed1986

Acute and long-term alterations in the granulocyte/macrophage progenitor cell (GM-CFC) compartment of dogs after partial-body irradiation: irradiation of the upper body with a single myeloablative dose.

The acute and long-term effects of a single dose of partial-body irradiation on the granulocyte/macrophage progenitor cell compartment were studied in dogs. A myeloablative dose of 11.7 Gy (dose rate 6.5 cGy/min) was given to the upper body which contains approximately 70% of the total bone marrow mass. The lower part of the body (pelvis, lower extremities and tail) was shielded by a lead box. In the non-irradiated bone marrow, the concentration of the GM-CFC/10(5) mononuclear cells was slightly decreased within the first 7 days and showed some fluctuations around the normal value for several weeks thereafter. In the irradiated bone marrow, virtually no GM-CFC could be detected on day 1 after exposure. Beginning on day 7, a continuous increase took place up to day 21 when the GM-CFC concentration reached between 25% (sternum) and 43% (humerus) of the initial value. No further increase took place up to day 80. Between day 120 and 380 a secondary increase was observed which reached near-normal bone marrow GM-CFC concentrations. The blood GM-CFC concentration first showed a strong depression followed by a transient increase between day 10 and 30. This coincided with GM-CFC normalization in the protected bone marrow as well as with the initial phase of regeneration in the irradiated sites. A prolonged secondary long-lasting depression between day 33 and 120 amounted to 20 to 50% of normal values. This depression was closely related to the stagnation in the GM-CFC recovery in the irradiated bone marrow sites. The GM-CFC concentration in the blood was found to be supranormal at day 380 when the bone marrow GM-CFC had recovered. The colony stimulating activity in the serum showed an increase within the first 20 days after exposure, that is, within the same interval the bone marrow GM-CFC concentration experienced the strongest alterations, and was inversely related to the changes in the blood granulocyte values.

Animals↗
PubMed1986

The development of radiation late effects to the bone marrow after single and chronic exposure.

The marrow is a tissue distributed in numerous skeletal parts and works as an organ which is composed of a haemopoietic cell parenchyma and a supporting stroma. The pathophysiological mechanisms involved in the radiation-induced late effects depend mainly on the damage produced to each of these elements. Parenchymal cell damage ends with a failure of the stem cell pool to supply an adequate number of highly differentiated functional blood cells and is clinically manifested as aplastic anaemia or leukaemia. The effects of radiation on the haemopoietic stem cell can be measured by means of spleen colony forming units (CFU-S) in rodents. The self-maintaining capacity of the CFU-S was found to be lower than normal 16 weeks after a dose of 0.64 Gy. In larger animals it is only possible to measure the activity of some of the progenitor cells, estimating the number of granulocyte-macrophage colonies in culture (CFU-GM) as an indicator of stem cell changes. Their number in the blood is about 50 per cent of normal even 160 days after about 0.78 Gy. The stromal cells are also radiosensitive if measured with respect to their capacity to support long-term cell replication in vitro. Marrow fibrosis develops after single, repeated and chronic radiation exposure, and a dose of 40 Gy impairs the capacity of the marrow to support haemopoiesis.

Anemia, Aplastic↗
PubMed1985

CFU-F from dog marrow: a colony assay and its significance.

A colony assay method is described for studying dog fibroblast colony development in marrow cells derived from resected ribs. The assay showed an increased number of fibroblast colony forming units (CFU-F) in cell suspensions prepared from resected ribs compared to cell suspensions prepared from bone marrow aspirates or from peripheral blood. A linear relationship between the number of cells plated and the number of fibroblastoid colonies was demonstrated in each case. The proportion of phagocytic cells was lower in cultures prepared from resected ribs than in those prepared from bone marrow aspirates. Staining for acid phosphatase and with sudan black showed differences between phagocytic cells and non-phagocytic fibroblasts. When left in plastic dishes for 2 hrs, 81% +/- 10% of the CFU-F adhered to the plastic dishes. Velocity sedimentation separation showed a modal sedimentation rate of 6.49 mm/h.

Animals↗
PubMed1985

Cell-culture studies on neurofibromatosis (von Recklinghausen's disease). III. Experiments on X-ray sensitivity.

The X-ray sensitivity of strains of fibroblast-like cells derived from peripheral neurofibromas of ten patients with neurofibromatosis was compared with that of 12 strains of skin fibroblasts derived from healthy donors. Quantitative parameters of the dose-dependent reduction in colony-forming ability did not differ significantly between these two groups of strains. The cloning efficiencies of nonirradiated controls varied within the same range in strains derived from patients and from healthy donors.

Cell Survival↗
PubMed1985

Repopulating potential of canine bone marrow cells: differences between large and small cells separated by velocity sedimentation.

This study compares the pattern of haemopoietic recovery in dogs after total-body irradiation and transfusion of different populations of cryopreserved autologous bone marrow cells. Dogs in group 1 received unseparated marrow cells. Group-II dogs were transfused with small (less than 5.1 mm/h) and group-III dogs with large (greater than 7.1 mm/h) bone marrow cells, separated by velocity sedimentation. Myeloid progenitor cells (CFU-GM) present in slowly sedimenting cell fractions were characterized by a higher radiosensitivity in vitro and a lower proportion of cells in S-phase as compared to rapidly sedimenting CFU-GM. Although autografts in all groups contained comparable numbers of CFU-GM, transfusions resulted in different patterns of recovery. Fractions of small bone marrow cells contained most of the pluripotent stem cells, leading to speedy haematological reconstitution and long-term survival. The pattern of early recovery was similar in dogs of group I and of group II. In group III, the recovery in all cell lineages was delayed, going along with marked extramedullary haemopoiesis. The data may indicate the limits of committed progenitors in reflecting pluripotential stem cells, in particular, if bone marrow grafts have been modified in vitro. Differences in the repopulating potential of the graft might be reflected by distinct physical and biological properties of the CFU-GM.

Animals↗
PubMed1985

Bone marrow structure and its possible significance for hematopoietic cell renewal.

The authors review the progress made during the last quarter of a century in the fields of hematopoietic cellular proliferation and differentiation in relation to the bone marrow structure and the microenvironment provided by the marrow stroma in which unlimited self-renewal occurs. The marrow is conceived of as an organ in which the stroma originates from local mesenchymal elements which form a vascularized and innervated matrix, seeded later by blood-borne stem cells. Transplantation studies using total-body-irradiated dogs show that stem cells derived from the marrow, as well as those from the blood and from the fetal liver, are able to repopulate a marrow rendered aplastic by irradiation. By grafting equal numbers of GM-CFU from peripheral blood and bone marrow, a faster hemopoietic reconstitution is provided by blood-derived stem cells. The most efficient stem cells in the long range are those derived from fetal liver. Bone marrow and peripheral blood GM-CFU differ in some in vitro characteristics such as radiation sensitivity. These peripheral blood cells are more radiosensitive than those derived from the marrow. Autografting of bone marrow mononuclear cell fractions obtained by velocity sedimentation techniques demonstrates that the fraction of small mononuclear cells holds a repopulating potential similar to that of circulating blood stem cells. The cells collected in fraction 2 of a discontinuous albumin gradient contain most of the blood stem cells and repopulate the marrow without causing GVHD, while cells collected in fractions 3 and 4 contain a minimal amount of stem cells and cause severe GVHD.

Animals↗
PubMed1985

Fetal liver transplantation in the dog. II. Repopulation of the granulocyte-macrophage progenitor cell compartment by fetal liver cells from DLA-identical siblings.

The restoration of the granulocyte-macrophage progenitor cell (CFU-GM) compartments in blood and bone marrow, and the recovery of blood monocytes were followed for up to one year in ten beagles that had been exposed to fractionated (3 X 6 Gy) total-body irradiation before being transfused with cryopreserved fetal liver cells (FLC) from sibling donors that were genotypically matched for dog leukocyte antigens. Grafts contained 0.2-1.6 X 10(8) mononuclear cells and 0.9-19.8 X 10(4) CFU-GM/kg body weight. Numbers of circulating monocytes rose parallel to granulocyte numbers after day 6 and became normal by day 18 posttransplant. In bone marrow aspirates, low numbers of CFU-GM were detected on day 3 and their incidence per 10(5) mononuclear cells was normal after day 14. Circulating CFU-GM were present in significant numbers by day 7 and their elevated concentration per milliliter of blood after day 14 continued for one year. Dextran sulfate injection mobilized normal numbers of CFU-GM into the blood early after transplantation, and spontaneously circulating CFU-GM in a later phase did not differ from blood progenitors of normal animals with respect to radiation sensitivity and sedimentation velocity. Thus, FLC transplantation effected a rapid restoration of granulopoiesis and monocytopoiesis, which was reflected at both the level of mature blood cells and the compartments of CFU-GM in blood and bone marrow, underlining the high repopulating capacity of fetal liver stem cells.

Animals↗