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W Nothdurft

Publications and source records attributed to W Nothdurft.

At least 55 records · Page 3Linked to original sources
PubMed1985

Allogeneic transplantation of blood stem cells concentrated by density gradients.

Discontinuous albumin density gradients were used to physically separate hemopoietic cells from immunocompetent lymphocytes in peripheral blood mononuclear cells of dogs. Transplantation of these stem cell concentrates into lethally irradiated allogeneic recipients restored hemopoiesis in nine of 12 animals. Tolerance and long-term survival, however, were achieved only in pairs matched for major histocompatibility antigens. These animals showed stable chimerism in bone marrow cells but transiently regenerated autochthonous cells demonstrable only in the peripheral blood. As compared with earlier studies using grafts of unseparated peripheral blood mononuclear cells, the numbers of CFUc transplanted were similar; the number of mononuclear cells, however, was reduced by a factor of 60. It thus appears that the granulocyte-macrophage colony-forming assay (GM-CFUc) is able to predict within limits the hemopoietic potential of a graft. Although very low numbers of blood-derived CFUc were effective (33,000-42,000/kg body weight), the superiority of blood stem cells over bone marrow grafts remains to be established.

Animals↗
PubMed1985

Canine blood mononuclear cells mediate contact-dependent impairment of granulocyte-macrophage colony formation by bone marrow cells.

Nonphagocytic, nonadherent mononuclear cells from canine peripheral blood (PBMC) were shown to suppress colony formation in agar of autologous and allogeneic bone marrow granulocyte-macrophage progenitor cells (CFU-GM). Suppression required previous cell-to-cell contact in liquid culture between PBMC and bone marrow cells (BMC) and was time- and dose-dependent and resistant to x-irradiation with 20 Gy. Small BMC were less susceptible than large BMC, whereas day-7 and day-14 CFU-GM were equally suppressed. Cryo-preservation of BMC did not enhance CFU-GM inhibition. Spontaneous inactivation during liquid culture of CFU-GM or accessory cells by PBMC is the likely effector mechanism. Possible recognition structures are different from dog leukocyte antigens A and B. Canine PBMC or subpopulations thereof might participate in the regulation of normal hemopoiesis and in the rejection of hemopoietic stem cell grafts by natural killer cell-like mechanisms as has been suggested for human and murine natural killer cells.

Animals↗
PubMed1984

Cytogenetic studies in dogs after total body irradiation and allogeneic transfusion with cryopreserved blood mononuclear cells: observations in long-term chimeras.

Cytogenetic studies were performed on two dog groups after total body irradiation and allogeneic transfusion with cryopreserved blood mononuclear cells. The first group of dogs was transfused with unseparated leukocytes and suffered from graft-versus-host disease (GvHD). Cytogenetic studies demonstrated only cells of donor origin in all dogs of this group. The second group of animals was transfused with fraction 2 of a discontinuous albumin gradient. The dogs of this group did not develop GvHD, and the cytogenetic studies showed the presence of a mosaic of cells from donor and recipient origin in all of them. These results suggest that the GvHD may suppress autochthonous regeneration.

Animals↗
PubMed1984

Characterization of erythroid and granulocyte monocyte progenitors in human cord blood.

Some characteristics of both erythroid and granulocyte monocyte progenitors in human cord blood were compared to those in adult blood and bone marrow. The number of progenitors in cord blood was higher than that in adult blood and bone marrow. Most colonies in cord blood culture were monocyte-macrophage, whereas those from adult blood were largely eosinophilic. Cord blood progenitors had a slower sedimentation velocity than that reported for marrow, but sedimented faster than that for adult blood. A significant proportion of progenitors in cord blood as well as adult marrow was found to be in the DNA synthetic phase of the cell cycle whereas progenitors in adult blood were not. Cord blood BFU-E were more resistant than adult blood BFU-E but cord blood CFU-GM were not different from adult blood CFU-GM with regard to radiation sensitivity. Cord blood CFU-GM appeared to be more radio-resistant than adult marrow GFU-GM. From these results is seems clear that progenitors in cord blood differ in some aspects from those in adult blood and bone marrow.

Bone Marrow Cells↗
PubMed1984

Dose- and time-related quantitative and qualitative alterations in the granulocyte/macrophage progenitor cell (GM-CFC) compartment of dogs after total-body irradiation.

The effects of single-dose total-body X irradiation (TBI) on the granulocyte/macrophage progenitor cell (GM-CFC) population in bone marrow and blood of dogs were studied for dose levels of 0.78 and 1.57 Gy up to 164 days after irradiation. The blood GM-CFC concentration per milliliter was depressed in the first 7 days in a dose-dependent fashion to 5-16% of normal after 0.78 Gy and to between 0.7 and 5% after 1.57 Gy. The bone marrow GM-CFC concentration per 10(5) mononuclear cells, on the other hand, was initially reduced to about 45% of the average pre-irradiation value after 0.78 Gy and to 23% after 1.57 Gy. The regeneration within the first 30 to 40 days after TBI of the blood granulocyte values and the repopulation of the bone marrow GM-CFC compartment was associated with both a dose-dependent increase in the S-phase fraction of the bone marrow GM-CFC and a dose-dependent increase in colony-stimulating activity (CSA) in the serum. The slow repopulation of circulating blood GM-CFC to about only 50% of normal even between days 157 and 164 after TBI could be related to a correspondingly delayed reconstitution of the mobilizable GM-CFC subpopulation in the bone marrow.

Animals↗
PubMed1984

Ontogeny of the granulocyte/macrophage progenitor cell (GM-CFC) pools in the beagle.

The pattern of development of the granulocyte/macrophage progenitor cell (GM-CFC) pools in the course of canine ontogeny was studied by means of the agar culture technique. Colony formation was stimulated by colony stimulating activity (CSA) in serum from lethally irradiated dogs in combination with erythrocyte-depleted peripheral blood leukocytes from normal adult dogs. The colonies thus obtained in cultures from the different organs were in general large (estimated maximum 50 000 cells) and consisted predominantly of mononucleated macrophages, suggesting that, in these studies, a progenitor cell with high proliferative potential (HPP-CFC) has been monitored. In the yolk sac, a transitory GM-CFC pool became established between day 23 and day 48 of gestation, reaching maximum numbers of approximately 41 X 10(3) per organ on days 36/37. At the same time the GM-CFC concentration in blood collected from the heart also reached a maximum of about 31 X 10(3)/ml, indicating its carrier function for the migration of GM-CFC. In the liver a quasi-exponential increase in the GM-CFC numbers took place between days 36/37 and days 57 to 59 when a total of about 15.2 X 10(6) was found but thereafter and up to day 4 post partum the GM-CFC numbers decreased by almost two orders of magnitude. A continuous increase in the GM-CFC numbers was found in the spleen between day 42 of gestation and day 4 post partum when a maximum of 5.1 X 10(6) to 8.7 X 10(6) was reached. In contrast to the GM-CFC numbers in the liver, the splenic GM-CFC dropped only by 50% of peak values when the dogs reached adulthood. The bone marrow always had the highest incidence of GM-CFC, the concentration per 10(6) cells being 18.7 X 10(3)/10(6) cells on days 45/46, the earliest time point at which cultures could be set up. The absolute GM-CFC numbers in the two femora increased continuously between days 45/46 and day 4 post partum in parallel with the growth of the bones. In the thymus a relatively small population of GM-CFC developed between days 42 and 48 of gestation that was kept quite constant at average numbers between 13 X 10(3) and 30 X 10(3) up to day 4 post partum.

Animals↗
PubMed1983

In vitro studies on the sensitivity of canine granulopoietic progenitor cells (GM-CFC) to ionizing radiation: differences between steady state GM-CFC from blood and bone marrow.

The radiosensitivity of the granulopoietic progenitor cells (GM-CFC) from blood and bone marrow of dogs under steady state conditions was studied by in vitro irradiation with 280kV X-rays (approximately 0.56 Gy/min). The dose-effect relationship for colony formation was determined for the dose range from 0 to 3 Gy by means of three different models. A simple exponential function revealed an optimal approximation to the experimental data obtained for the clonogenic cells from the two different sources. The D0 values are 0.261 +/- 0.009 Gy and 0.600 +/- 0.011 Gy for the GM-CFC from blood and bone marrow, respectively. Irradiation of blood-derived GM-CFC in the presence of pre-irradiated bone marrow cells or irradiation of bone marrow cells as a mixture with pre-irradiated blood cells led to small changes only in the survival curves. According to the dose-effect relationship obtained from these studies the GM-CFC of the dog seem to be the most radiosensitive clonogenic haemopoietic cells among the different mammals.

Animals↗
PubMed1982

Quantitative aspects of granulocytic progenitor cell (CFUc) mobilization from extravascular sites in dogs using dextran sulphate (DS).

The relationship between the increase in the blood CFUc concentration after intravenous injection of dextran sulphate (DS) and the pre-existing levels of spontaneously circulating CFUc was studied in dogs. After 15 mg DS/kg body weight the CFUc numbers per ml blood rose by a factor of 3.7 over the pre-injection values, from 78 +/- 11 (SEM) to 359 +/- 50, in normal dogs, and increased by a factor of 3.9 in 0.84-Gy-r-irradiated animals which had a reduced initial CFUc concentration per ml, from 35 +/- 8 to 116 +/- 43. The injection of 20 mg DS/kg body weight into unirradiated dogs caused an increase, by a factor of 11.5, of the pre-injection CFUc concentration, from 101 +/- 20 to 921 +/- 106. On the basis of the mobilization curves for individual dogs, a significant correlation was found between the normal blood CFUc value and the number of CFUc mobilized by DS for both dose levels. From the descending part of the mobilization curves obtained after 15 mg DS/kg body weight, kinetic parameters of canine circulating CFUc were derived. The mean blood transit time (t) was 1.4 +/- 0.5 hr and the half time (T/2) was 1.0 +/- 0.4 hr.

Animals↗
PubMed1982

Effect of low-dose whole-body irradiation on granulopoietic progenitor cell subpopulations: implications for CFUc release.

The reaction of the granulopoietic system to whole body irradiation with 0.80 and 1.60 Gy was studied in dogs by means of colony formation assays in combination with velocity sedimentation and tritiated thymidine cytocidal techniques. Depression of circulating CFUc was associated with a marked shift in the size distribution of granulopoietic progenitors in the bone marrow. This effect lasted much longer in those animals receiving the lower X-ray dose. We conclude that circulating CFUc are not a random proportion of the bone marrow but a subpopulation of cells which are smaller in size. These cells are in an equilibrium with the larger marrow CFUc, which is very sensitive to perturbations.

Animals↗
PubMed1982

Extracorporeal irradiation of dog blood: the effects of a radiostrontium irradiator on blood stem cells (CFU-C).

The radiation sensitivity of dog blood stem cells was measured in vitro and in an extracorporeal circulation passing through a radiation field. It was established that the calculated D0 was as low as 0.45 Gy. Investigating the cell killing rate in our equipment (Buchler type 90Sr device for extracorporeal irradiation), we found an overkill situation; the dose delivered was in excess of that which would be required for the total eradication of all stem cells in the peripheral blood passing through the radiation field. Various other types of devices used for extracorporeal irradiation of blood are also reviewed.

Animals↗
PubMed1981

[Granulopoietic progenitor cells and the hemopoietic potential of a graft: a study in the dog model (author's transl)].

Four beagles received a standardized dose of 33000-44000 CFU-C per kg b.w. isolated from the peripheral blood of DLA-identical donors. Three had permanent reconstitution of hemopoiesis while in one regeneration was abortive. This indicates that the CFU-C assay is able to predict for the hemopoietic potential of a graft. However, considerable differences in the regeneration pattern of CFU-C in the bone marrow demonstrated that the number of repopulating stem cells was variable.

Animals↗
PubMed1980

Investigations on the pool size, proliferative state and differentiation pattern of splenic CFUC in normal dogs.

In the present study we investigated the absolute numbers of granulocytic progenitor cells (CFUc) in the spleens of adult normal dogs, their differentiation pattern and also their proliferative state. Between 10 and 40 times as many CFUc were found in the spleens of individual dogs as were present in the total blood volume at the same time under physiological conditions. About 16% of the splenic CFUc were in the DNA synthetic phase. In spite of the presence of CFUc in the splenic tissue, there was a lack of morphologically identifiable granulocytic precursor cells and hence no extramedullary granulocyte production. The similarities between circulating CFUc and the splenic CFUc with respect to their differentiation pattern in vitro and their cell cycle state suggest that the CFUc that reside in the splenic tissue are identical to thea CFUc population in the circulation.

Animals↗
PubMed1979

Collection, storage and transfusion of blood stem cells for the treatment of hemopoietic failure.

Migration of hemopoietic stem cells via the blood to sites of stem cell need is a principle that becomes established during the embryonic development of hemopoiesis and can be observed in the adult whenever bone marrow transplantations are being performed. The regular presence of stem cells in the peripheral blood lends itself to the study of their collection, storage, and use for transfusion purposes in cases of bone marrow failure. Both in dog and in man, granulocyte-macrophage progenitor cells (CFU-C) can be collected by leukapheresis from the blood in large quantities, particularly if the yield is increased by the administration of mobilizing agents such as dextran sulfate, and appear to be an indicator for the presence of stem cells. For collection and storage, a closed plastic bag system has been developed that allows the safe handling of the cells. The loss of CFU-C from freezing and thawing with DMSO as a cryoprotective agent is only 10%-20%. If frozen and thawed mononuclear leukocytes are transfused into 1200 rad whole-body X-irradiated autologous or allogeneic recipient dogs, a hemopoietic take is observed when 0.2 X 10(5) CFU-C are present among the mononuclear leukocytes (MNC). Graft-versus-host disease can be avoided in the allogeneic situation when a purified CFU-C rich cell fraction is being transfused. In man collection and storage of MNC including CFU-C is feasible and may eventually become a therapeutic tool.

Animals↗
PubMed1979

Albumin density gradient purification of canine hemopoietic blood stem cells (HBSC): long-term allogeneic engraftment without GVH-reaction.

Long-term repopulation of the blood-forming organs of dogs, conditioned by wholebody X-irradiation (1200 R midplane dose), was achieved by transfusion of cryopreserved allogeneic blood mononuclear cells (MNC) without causing graft-versus-host-reaction (GVH-R). Donor and recipient dogs were DL-A identical, MLC-negative, no siblings, non-related. The blood stem cells (CFUc) were procured by a 3- to 4-hour continuous-flow leukapheresis. To increase the CFUc concentration in the peripheral blood, dextran sulfate (DS) was administered intravenously beforehand. About 1 x 10(10) MNC, among them about 1 x 10(7) CFUc, were collected and further segregated using a discontinuous albumin density gradient. Less dense cells were to be found in the upper part of the gradient (fraction 2). These cells included most of the CFUc, enriched by a factor of between 275 and 1730 compared to their concentration in the peripheral blood beforehand. After cryopreservation, these cells, when transfused into lethally irradiated dogs, completely repopulated the marrow and lymph nodes, caused no GVH-R and allowed long-term survival. These dogs received no immunosuppressive therapy, either before or after transfusion. More dense MNC were to be found in fraction 3; their transfusion caused a severe GVH-R, followed quickly by death. Fraction 4 was rich in lymphocytes and poor in CFUc. The transfusion of these cells produced a selective plasma-cell hyperplasia of the lymph nodes but failed to repopulate permanently the marrow. The reappearance of the different cell lineages in the marrow and in the peripheral blood after conditioning and transfusion of these cells produced a selective plasma-cell hyperplasia of the lymph nodes but failed to repopulate permanently the marrow. The reappearance of the different cell lineages in the marrow and in the peripheral blood after conditioning and transfusion of the segregated MNC is described in detail.

Animals↗