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Biomedical subjects

T M Fliedner

Publications and source records attributed to T M Fliedner.

At least 181 records · Page 10Linked to original sources
PubMed1977

Cryopreservation of blood mononuclear leukocytes and stem cells suspended in a large fluid volume. A preclinical model for a blood stem cell bank.

It was the purpose of this study to establish and evaluate a freezing-and-thawing method for preservation of hemopoietic stem cells from the peripheral blood. Blood leukocytes collected by means of an IBM Blood-Cell-Separator were frozen in plastic bags using 10% DMSO and controlled cooling rates. Thawing was performed rapidly, and DMSO was diluted and removed prior to the in-vitro and in-vivo assays. The mean recovery of mononuclear cells collected from 82 leukaphereses was 86%. To assess the recovery of cryopreserved hemopoietic stem cells, the soft agar culture method adapted for the dog was used. There was no significant difference in the CFUc recovery per 1 X 10(6) mononuclear cells or in per leukapheresis after different cryopreservation times (1--6 and 7--27 months). To evaluate the hemopoietic repopulation capability of cryopreserved blood stem cells, leukapheresis-derived leukocytes were transfused into 1200 R whole body x-irradiated dogs. The hemopoietic repopulation pattern at day 10 after transfusion of comparable numbers of fresh or frozen leukocytes was not significantly different, as measured in bone marrow smears and sections and by granulocyte concentration in the peripheral blood.

Animals↗
PubMed1977

Allogeneic bone marrow transplantation in conventional mice: I. Effect of antibiotic therapy on long term survival of allogeneic chimeras.

In the present communication the beneficial effect of long term antimicrobial treatment with poorly absorbable antiboitics on the survival of allogeneic bone marrow chimeras was investigated. The combination of C57Bl mice as bone marrow donors and CBA/CA mice as irradiated recipients (800 rad) was used because of their strong histoincompatibility on the H-2 loci. All allografted recipients received 10 X 10(6) bone marrow cells. The majority of the recipients, which were rendered gnotobiotic by an antimicrobial treatment, achieved stable long term chimerism. In contrast, the conventional chimeras died from secondary disease within 9 weeks after transplantation. As early as 14 days after allogeneic bone marrow grafting the gnotobiotic recipients tolerated the reassociation with a conventional microflora without a change in the rate of mortality. Bone marrow cells (8 X 10(6) i.v.) and spleen cells (2 X 10(6) i.v.) collected from allogeneic chimeras failed to induce graft-versus-host-reaction (GVH) in a second lethally irradiated host. The data indicate, that the high rate of mortality in murine allogeneic bone marrow chimeras results from delayed GVH-reaction and systemic infection. The marrow graft, once established seems to exert tolerance against the allogeneic host. The pathogenesis of the systemic infection has not yet been worked out. It is assumed that it originates from bacteremia, induced by radiation dependent lesions of the epithelial integrity and defected lymphatic tissue in the gut.

Animals↗
PubMed1977

Studies on the regeneration of the CFU-C population in blood and bone marrow of lethally irradiated dogs after autologous transfusion of cryopreserved mononuclear blood cells.

In a group of 8 lethally irradiated (1200 R) dogs, that were transfused autologously with cryopreserved mononuclear cells (MNC) derived from the peripheral blood by leucapheresis the concentration of colony-forming units in agar (CFU-C) in bone marrow and peripheral blood was estimated at regular intervals after irradiation and transfusion of MNC. The numbers of MNC transfused per kg body weight ranged from 0.32 x 10(9) to 1.63 x 10(9) with an incidence of CFU-C between 0.02 x 10(5) and 1.38 x 10(5). In 6 dogs the CFU-C levels in the bone marrow reached the normal pre-irradiation values between days 15 and 20. But in 2 dogs that had received the lowest CFU-C numbers the regeneration of the bone marrow CFU-C was markedly delayed. In general the time course of the bone marrow repopulation by CFU-C for single dogs was reflected by a corresponding regeneration pattern of the blood CFU-C. The time course of the curves for the blood CFU-C levels on the other hand was of the same kind as for the granulocyte values in the peripheral blood, thuations were seen in the blood CFU-C levels of single dogs before irradiation and after mononuclear leucocyte transfusion. Despite of such limitations the blood CFU-C content appeared to be a useful indicator of haematopoietic regeneration of the bone marrow.

Animals↗
PubMed1977

Behavior of leucocytes and colony-forming units (CFU-C) in blood of chronic uremic patients during hemodialysis and hemodiafiltration.

In a comparison of the effects of hemodialysis and diafiltration, we found that the transient decrease of circulating granulocytes seen in hemodialysis did not occur during diafiltration. We assume that this is the consequence of effective removal of a humoral leucotoxin by hemofiltration. The CFU-C changes observed parallelled the alterations in the granulocyte count both in hemodialysis and in hemodiafiltration.

Adult↗
PubMed1977

Specific absorbed antithymocyte globulin for incubation treatment in human marrow transplantation.

The experimental data show that absorption of ATG with liver-kidney homogenate and CLL and LCL cells stepwise removed the hemopoietic toxicity, whereas the specific activity against T lymphocytes remained. Although the mode of action of absorbed ATG could not be tested in the first clinical case, the successful experiments in rodents together with the fact that the incubation treatment was tolerated by the patient may provide a new way of preventing fatal GVH reactions in man.

Animals↗
PubMed1977

In-vitro and in-vivo properties of canine blood mononuclear leukocytes separated by discontinuous albumin density gradient centrifugation.

Dogs were given 1 200 R whole body x-irradiation and transfused with frozen and thawed mononuclear leukocytes from a DLA identical, MLC negative donor dog. These leukocytes had been obtained from the peripheral blood by means of leukapheresis, using the IBM experimental cell separator after injection of 15 mg/kg body weight of dextran sulphate to increase the yield of CFUc upon collection. The segregation of leukocytes by means of the discontinuous albumin gradient centrifugation method resulted in a fraction 2 that contained a very high proportion of CFUc, and in other fractions 3 and 4 with a high proportion of lymphocytes with few CFUc. The dog receiving fraction-2 cells showed a rapid bone marrow recovery (permanent) and displayed no signs of gvh-reaction. The dogs receiving cells of fraction 3 or 4 died of gvh-reaction within 25 days. The dog receiving fraction 4 cells showed little hemopoietic recovery, but a marked lymph node hyperplasia of plasma cells.

Animals↗
PubMed1976

Colony formation by canine hemopoietic cells in vitro. Inhibition by polymorphonuclear leukocytes.

In soft agar cultures of canine blood leukocytes, an inhibition of colony formation was observed relative to the size of the inoculum. Analysis of the cellular composition of the inoculum suggested that this inhibition was associated with the number of polymorphonuclear leukocytes present. Removal of phagocytic cells by the iron ingestion method or selective destruction of granulocytes by freezing in the presence of dimethyl sulfoxide eliminated the inhibitory action on colony formation. In mixed cultures of canine bone marrow and antologous blood leukocytes, a similar inhibition of colony formation was observed. The results presented indicate that polymorphonuclear leukocytes, if present in a concentration exceeding 2.5X10(6)/ml of inoculum, inhibit in vitro granulocytic/monocytic colony formation.

Animals↗
PubMed1976

Regeneration of blood-forming organs after autologous leukocyte transfusion in lethally irradiated dogs. II. Distribution and cellularity of the marrow in irradiated and transfused animals.

Dogs were given transfusions of cryopreserved autologous mononuclear blood leukocytes after 1200 roentgens (R) (midline dose) whole-body x-irradiation. Bone marrow repopulation was studied by means of histomorphological methods at days 9 and 10 after transfusion of an average of 3 X 10(9), 7 X 10(9), 13 X 10(9), and 31 X 10(9) cells. The return of marrow cellularity to normal values was related to the number of cells transfused. With low cell doses (3 X 10(9) and 7 X 10(9)), the marrow regeneration at 10 days was focal. There were groups of cells (colonies) showing either erythropoiesis, myelopoiesis, or megakaryocytopoiesis in the osteal niches of the trabecular bones. Frequently such niches were seen showing complete cellular recovery next to niches with complete aplasia. With higher cell doses, all niches showed hemopoietic regeneration, and the cellularity approached normal values. No hemopoietic regeneration was observed in those skeletal parts that do not show hemopoiesis, even under normal circumstances.

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