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Biomedical subjects

H Kaizer

Publications and source records attributed to H Kaizer.

At least 55 records · Page 3Linked to original sources
PubMed1987

Treatment of poor prognosis non-Hodgkin's lymphoma using cyclophosphamide and total body irradiation regimens with autologous bone marrow rescue.

Twenty patients with poor prognosis non-Hodgkin's lymphoma received regimens which employed cyclophosphamide and total body irradiation followed by autologous bone marrow rescue. There were two toxic deaths. All 10 patients with residual disease prior to treatment achieved a complete remission. Ten patients survive disease free from 1.4 to 9.5 years and median survival exceeds 2.9 years. The actuarial 3-year disease-free survival is 50%. Treatment with cyclophosphamide and total body irradiation followed by autologous bone marrow infusion is an effective salvage regimen for poor prognosis lymphoma. Durable long-term remissions can be achieved.

Adolescent↗
PubMed1987

Formation of macrophage (M) colony-stimulating factor by murine leukemia x fibroblast hybrid cells.

Clonogenic assays for M, GM, and G precursors of rat or mouse marrow cells were performed in the presence of medium conditioned by the growth of ASL-1 leukemia X LM fibroblast hybrid cells. Both GM- and M-colony-forming units (CFUs) were present in marrow cultures maintained in conditioned medium (CM) from hybrid cells (up to 162 +/- 10 total colonies per 10(5) cells) and from LM cells (65 +/- 5). Conditioned medium from ASL-1 cells did not lead to the formation of CFUs. The hybrid cell-derived CM supported the development of M and GM-CFUs from the marrows of DBA, CAF1, BDF1, C3D2F1, and C57B1/6 mice as well as Lewis, Brown Norway, and Wistar Furth rats. G-CFU were not detected in any of the preparations. Hybrid cell-CM supported the long-term growth and proliferation of macrophage-like cells from mouse spleen, consistent with the presence of M-colony-stimulating factor (CSF). Evidence that M-CSF formed by the hybrid cells and M-CSF formed by L cells shared structural features was provided by antibody neutralization studies. The CFU-promoting activity of hybrid cell-derived M-CSF was neutralized by an antiserum raised in goats against M-CSF purified from L cells. Independently prepared ASL-1 X LM hybrid cells, like the original, led to the formation of GM and M-CFUs. Attempts to detect each of several other previously defined growth factors in medium conditioned by the hybrid cells were unsuccessful. Interleukins 1, 2, and 3; B cell growth factors interferons alpha, beta, and gamma; erythropoietin; and burst promoting factor were not detected.

Animals↗
PubMed1987

Biotransformation of primaquine in vitro with human K562 and bone marrow cells.

Although the antimalarial activity, hemolytic and methemoglobinemic side effects, and detoxification of primaquine are all thought to depend on various biotransformation products of the drug, their site and mechanism of formation and degradation are unknown and their specific biologic effects remain very poorly understood, particularly in humans. We have therefore explored the feasibility of studying primaquine metabolism in cultured human cells. We found that the biotransformation of primaquine can be investigated in vitro in serum-supplemented liquid cultures of partially synchronized and exponentially growing human erythroleukemic K562 cells. Further, these cells can be replaced by cells present in normal bone marrow. Primaquine is rapidly and predominantly converted in vitro into carboxyprimaquine (CPQ) in a quantitative manner and without further modification. In addition to CPQ, a compound Xc that is not 6-methoxy-8-aminoquinoline, and is not derived from CPQ, appears in minor amounts in a delayed fashion. With the K562 as well as with the bone marrow cells the formation of CPQ from primaquine can be totally blocked by large concentrations of the nitrosourea, 1,3-bis-(2-chloroethyl)-nitrosourea (BCNU). With bone marrow, increasing blockade of CPQ formation by BCNU leads invariably to a progressive and striking accumulation of Xc. The availability of reproducible, quantitative, and practical new tools for the study of primaquine metabolism in vitro raises a number of challenging questions and may improve understanding of the mode of action, toxicology, and pharmacogenetics of 8-aminoquinolines.

Biotransformation↗
PubMed1986

Autologous bone marrow transplantation in patients with acute nonlymphocytic leukemia, using ex vivo marrow treatment with 4-hydroperoxycyclophosphamide.

We studied 25 patients with acute nonlymphocytic leukemia in second remission (20 patients) or third remission (5 patients) in whom autologous bone marrow transplantation was performed with use of marrow incubated ex vivo with the alkylating agent 4-hydroperoxycyclophosphamide. Patients received intensive cytoreductive therapy with busulfan and cyclophosphamide or cyclophosphamide and total body irradiation, followed by an infusion of marrow that had been collected in remission, treated with 4-hydroperoxycyclophosphamide, and cryopreserved. Four patients died from bacterial or fungal sepsis within the first month after transplantation, and one patient with persistent marrow hypoplasia died from gram-negative sepsis 155 days after infusion with autologous marrow. In the remaining patients, peripheral-blood levels of neutrophils in excess of 0.5 X 10(9) per liter and platelet counts over 50 X 10(9) per liter were attained at median intervals of 29 and 57 days after transplantation, respectively. Nine patients had leukemic relapses at 73 to 316 days (median, 182 days) after infusion of autologous marrow, for an actuarial relapse rate of 46 percent. Eleven patients (eight in second remission and three in third) remained in remission at a median of more than 400 days (range, greater than 230 to greater than 1653 days) after transplantation. The observed disease-free survival after transplantation with autologous marrow treated with 4-hydroperoxycyclophosphamide compares favorably with the results of syngeneic or allogeneic transplantation in similar groups of patients.

Acute Disease↗
PubMed1985

Loss weighting and the human cost of experimentation.

This paper analyzes the dilemma faced by clinicians who must determine a proper sample size for a clinical trial. A large sample size may be used to ensure significant results. In so doing, many patients may be randomized to the wrong arm of a clinical trial. Alternatively, fewer patients may be used in a clinical trial, however, the resulting conclusions will be less certain, and future patients may be harmed by false conclusions. This study introduces a ratio of relative human cost or loss associated with a single present patient receiving incorrect therapy during the clinical trial to a single future patient given incorrect therapy after the trial is over. This "loss weighting" ratio can be estimated, the trade-off between present and future loss can be evaluated and the total loss from a clinical trial can be minimized. The resulting method, based on the loss weighting ratio, suggests an inverse relationship between the number of future patients potentially affected by a clinical trial and the size of desired type I and type II error. The conclusions derived from this paper can be incorporated easily into the current process of sample size determination. This is illustrated with examples from two well-known clinical trials.

Clinical Trials as Topic↗
PubMed1985

Autologous bone marrow transplantation in acute leukemia: a phase I study of in vitro treatment of marrow with 4-hydroperoxycyclophosphamide to purge tumor cells.

This phase I study was conducted to determine the maximal safe concentration of 4-hydroperoxycyclophosphamide (4HC) that could be used for in vitro treatment of bone marrow from patients with acute leukemia undergoing autologous bone marrow transplantation. Concentrations of 40 to 120 micrograms/mL of 4HC were used in 30 patients with relapsed or high-risk acute leukemia and in six patients with nonleukemic malignancies. All patients received marrow-lethal cytoreductive therapy followed by infusion of the 4HC-treated marrow. Complete inhibition of granulocyte and macrophage colony-forming cells was obtained at 80 micrograms/mL. Nevertheless, only one transplant-related death and otherwise full hematologic recovery was observed at concentrations of 4HC up to 100 micrograms/mL. At 120 micrograms/mL, there were three transplant-related deaths, including two of the three patients who required the infusion of reserve marrow. Among the acute leukemia patients, three remain in complete remission at 1,337, 1,017, and 967 days after transplant. Among the nonleukemic patients, two remain in complete remission at 1,081 and 1,017 days after transplant. At the maximum safe concentration of 4HC (100 micrograms/mL), satisfactory hematologic recovery can be obtained, despite elimination of detectable hematopoietic progenitors.

Acute Disease↗
PubMed1985

Role of endogenous complement in monoclonal IgM antibody-dependent leukemia suppression in vivo: participation of C3b.

The mechanism by which McAb of the IgM isotype causes prolonged survival of leukemic rats was investigated. The participation of endogenous C in the suppression of IgM-sensitized leukemia cells was demonstrated by the observations that a) suppression was abrogated in CVF-treated rats, and b) the CVF effect was partially reversed if C3b was provided on the surface of IgM-sensitized leukemia cells.

Animals↗
PubMed1984

Autologous bone marrow transplantation (ABMT) in the treatment of cancer.

Clinical trials in autologous BMT to date have indicated that significant salvage and potential cures can be obtained in patients with high grade non-Hodgkin's lymphoma (NHL) who have failed primary therapy and are treated with high dose chemoradiotherapy and autologous marrow rescue. The major need in NHL is to better define those patients who might benefit by autologous BMT and to reduce the relapse rate by improved pre- or post-transplant therapy. Similar results to those in NHL could be obtained in acute leukemia if occult tumor cells could be eliminated from autologous marrow. Animal model experiments have shown that it is feasible to eliminate low level contamination with tumor cells by in vitro immunologic or pharmacologic treatment. While it is too early to accurately assess the efficacy of ongoing clinical trials using those marrow purging techniques, a few patients have exhibited encouraging durations of CCR. Should these approaches prove to be effective in only a fraction of cases, combination in vitro treatment or the use of more efficient effector mechanisms for cell killing (e.g., ricin conjugated antibody) may very well clear occult tumor from the marrow of most patients. The encouraging results with autologous BMT in leukemia and lymphoma stand in sharp contrast to the disappointing results so far achieved with the non-hematologic solid tumors. It is, however, possible that those cancers have not been subjected to the most rigorous test for successful autologous BMT and that the search for newer agents which can produce operationally irreversible aplasia may provide a fairer test of this approach. It is to be hoped that future research will settle this point.

Acute Disease↗
PubMed1984

Preliminary results of high-dose busulfan and cyclophosphamide with syngeneic or autologous bone marrow rescue.

The toxic effects of high-dose busulfan (16 mg/kg) and cyclophosphamide (200 mg/kg) with autologous or syngeneic bone marrow rescue were evaluated in 19 patients (11 with acute myelocytic leukemia, one with acute lymphocytic leukemia, one with acute myelofibrosis, two with chronic myelocytic leukemia, one with Hodgkin's disease, and three with non-Hodgkin's lymphoma). Their mean age was 26 years (range, 6-50); nine patients had syngeneic and ten had autologous bone marrow rescue (six of whom had in vitro bone marrow incubation with 4-hydroperoxycyclophosphamide). Severe myelosuppression was expected and was seen in all patients; leukocyte and platelet count recovery occurred at a median of 19 days (range, 11-59) and 30 days (range, 20-89), respectively. Nausea, vomiting, and diarrhea were frequent but readily managed with vigorous medical therapy. Stomatitis was severe in 14 patients. Skin, renal, cardiac, pulmonary, and CNS complications directly attributable to drug-related toxic effects were transient and non-life-threatening. Hepatic function abnormalities were common but tended to be transient. Most patients tolerated high-dose busulfan and cyclophosphamide with manageable side effects. Hepatic veno-occlusive disease was fatal in two patients, while diffuse interstitial pneumonitis with disseminated herpes virus infection was fatal in three patients with lymphoma. All patients treated in relapse or without previous therapy had a complete tumor response. Further studies with this regimen should be pursued.

Acute Disease↗
PubMed1984

Characteristics of a monoclonal antibody (RM124) against acute myelocytic leukemia cells.

A monoclonal antibody was raised against cells from an experimental rat myelocytic leukemia (BNML). The major characteristics of the rat leukemia model resemble those of human acute myelocytic leukemia. The monoclonal antibody (MCA) RM124 was characterized with respect to its labeling pattern of BNML leukemia cells, normal rat bone marrow cells, and the hemopoietic stem cell (HSC), by flow cytometric methods and complement-dependent cytotoxicity assays. Flow cytometry revealed a much higher labeling of the leukemic cells by the MCA-RM124 compared with normal bone marrow cells, including CFU-S and CFU-C. Only a subpopulation of the normal granulocytes showed cross reactivity, however, at a lower labeling density. On using the cytotoxicity assays, it was evident that there was a selective killing of leukemic cells as compared with the activity towards the normal hemopoietic stem cells (CFU-S).

Animals↗
PubMed1983

Marrow transplantation for acute nonlymphocytic leukemia after treatment with busulfan and cyclophosphamide.

Fifty-one patients with acute nonlymphocytic leukemia (16 with end-stage disease, 17 in second or third remission or in early relapse, and 18 in first remission) were given infusions of HLA-identical sibling marrow after cytoreduction with high doses of busulfan and cyclophosphamide. Actuarial two-year survival rates were 0 per cent, 29 per cent, and 44 per cent, respectively. Twelve patients are still alive and in remission after 327 to 1488 days, with 10 surviving beyond two years. Acute graft-versus-host disease and viral pneumonia were the major causes of death. Leukemic cells failed to clear in one patient with end-stage disease, and a relapse with meningeal leukemia occurred in another. Only one other relapse was seen--in a patient given a transplant during a third remission. Survival was favorably affected by younger age and transplantation during first remission. We conclude that high-dose chemotherapy with busulfan and cyclophosphamide, followed by allogeneic-marrow transplantation, can produce long-term remission of acute leukemia. Chemotherapy with high-dose busulfan and cyclophosphamide before transplantation provides an effective alternative to cyclophosphamide and total-body irradiation before transplantation for the treatment of acute nonlymphocytic leukemia.

Acute Disease↗
PubMed1983

Downbeat nystagmus. A case report of herpetic brain stem encephalitis.

A 35-year-old man with aplastic anemia developed prominent downbeat nystagmus 80 days after receiving an allogeneic bone marrow transplant. A diagnosis of herpes simplex encephalitis was made which was confirmed by positive virus cultures at autopsy 1 week later. Routine pathologic examination of the brain stem revealed no lesions which would explain the downbeat nystagmus. Immunoperoxidase studies, however, revealed virus-infected neurones throughout the brain stem including the nuclei of the basis pontis, the superior olive, and nuclei of the spinal tracts of 5 and 10. The significance of "negative" pathologic brain stem findings in cases of downbeat nystagmus is discussed.

Adult↗
PubMed1982

4-hydroperoxycyclophosphamide: a model for eliminating residual human tumour cells and T-lymphocytes from the bone marrow graft.

Autologous bone marrow transplantation in acute leukaemia carries the risk of relapse from reinfusion of tumour cells present in marrow collected in remission and cryopreserved. An effective method for clearing marrow of tumour cells is required for a successful outcome. In the animal model 4-hydroperoxycyclophosphamide (4-HC) has proved to be effective in eliminating tumour cells from an autologous marrow graft. In the present studies, the in vitro effect of short- and long-term marrow cell incubation with 4-HC on haemopoietic stem cells was investigated to determine the maximum concentration of 4-HC that can be used for in vitro incubation without destroying the capacity of the marrow to effect complete haematological recovery as judged by residual CFUc content. However, loss of CFUc may not necessarily parallel survival of pluripotential stem cells. 4-HC was also shown to be effective against peripheral T-lymphocytes. Its possible therapeutic use in preventing or ameliorating graft-versus-host disease in allogeneic marrow grafts by preincubation with 4-HC prior to transplantation is discussed.

Bone Marrow Transplantation↗