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B D Clarkson

Publications and source records attributed to B D Clarkson.

At least 73 records · Page 4Linked to original sources
PubMed1986

High resolution banding of chronic myeloid leukemia chromosomes.

Bone marrow aspirates from 29 patients with chronic myeloid leukemia were studied using the methotrexate synchronization culture method. Successful cytogenetic preparations exhibiting long and well banded chromosomes were obtained from all of them. The standard t(9;22) was seen in 23 patients, four had variant translocations, and two were Ph-negative. Of the four patients with variant translocations, one had a simple translocation in which the missing segment of chromosome #22 was translocated onto the short arm of chromosome #9. The remaining three patients had complex translocations. The first involved chromosomes #11, #19, and #22, the second involved chromosomes #9, #11, and #22, and the third involved chromosomes #9, #14, and #22. Karyotypic abnormalities in addition to the Ph chromosome were seen in four patients: in three these changes developed during the chronic phase and in one during the blastic phase. Using Q-, R-, and G-banding techniques, we found that the breakpoint on chromosome #22 is just below the centromere, namely in band 22q11.2 and on chromosome #9 in band 9q34.1. The standard translocation, therefore, can be written as t(9;22)(q34.1;q11.2). Furthermore, the breakpoint on 22q appeared to be identical in all cases with standard as well as the variant translocations. Our results show that the methotrexate synchronization method permits consistent high resolution banding of CML chromosomes, and support the concept that there is no difference in the amount of material translocated from 22q in different patients.

Adolescent↗
PubMed1986

Evaluation of malignant lymphomas using three classifications and the working formulation. 482 cases with median follow-up of 11.9 years.

Three classifications and the Working Formulation for non-Hodgkin's lymphomas have been studied in 482 patients with a median follow-up of 11.9 years. Each classification was evaluated independently, and their similar and discrepant aspects were analyzed by comparing subgroups in the different schemes. Clinical staging was essential in the evaluation of some categories. There are several differences between the classifications that are not readily reconcilable. The Rappaport classification's principal groups are heterogeneous. Separation of follicular lymphomas into small and large cleaved cell types (Lukes-Collins) is significant. The addition of a follicular mixed cell type (Rappaport, Working Formulation) detracts from this significance. Centrocytic and lymphoplasmacytic tumors (Kiel) are well-defined categories and important in understanding some deficiencies in the other classifications. The small cleaved cell type, diffuse (Lukes-Collins, Working Formulation) is heterogeneous. Diffuse lymphomas of mixed cell types are poorly defined subgroups. Excluding lymphoblastic types, the presence of plasmacytic differentiation is important in identifying the high-grade lymphomas with the poorest prognosis. These results suggest that adjustments should be made in the classifications and in the Working Formulation.

Adolescent↗
PubMed1986

Current status of treatment of acute leukemia in adults: an overview of the Memorial experience and review of literature.

The results of treatment of 629 previously untreated adults with acute leukemia at Memorial Hospital are reviewed. During the past 14 years, 135 adults (greater than 15 years) with acute lymphoblastic leukemia (ALL) have been treated with one of three successive multidrug-intensive treatment protocols (L2, L10/10M, and L17/17M), each calling for 2.5 to 3 years of systemic chemotherapy and prophylactic intrathecal methotrexate without cranial irradiation. The complete remission (CR) rates were L2 (n = 22) = 77%; L10/10M (n = 69) = 86%; L17/17M (n = 44) = 77%. The median durations of survival and remission were, respectively, L2 = 33 and 30 months; L10/10M = 62 months and not reached; and L17/17M = not reached. Almost all relapses occurred within the first 3 years while still continuing treatment, and there were only rate late relapses after stopping treatment. It appears that approximately half of the patients may have been cured with the latest two protocols. During the last 17 years, 494 adults aged 15 to greater than 70 with acute nonlymphoblastic leukemia (ANLL) were treated with one of five successive multiple drug treatment protocols of varying intensity (arabinosylcytosine + 6-thioguanine [n = 36]; L6 [n = 101]; L12 [n = 104]; L14/14M [n = 121]; and L16/16M [n = 132]). Patients with myelodysplastic syndromes generally were not treated until they developed acute leukemia, but were then entered and included in the results. Secondary leukemias following treatment of other neoplastic diseases were not included. The complete remission rates were fairly constant between 47 and 64% and the median durations of remissions were between 9 and 21 months. The intensive treatment L14 and L16 protocols were associated with more early deaths and did not result in a significantly improved remission incidence or duration or survival. With all protocols, the majority of relapses occurred within the first 2 years, but relapses continued to occur at a decreasing rate for 4 years and occasionally even later. Whereas a small fraction (approximately 10 to 15%) of adults with ANLL are now apparently being cured with combination chemotherapy, despite intensive efforts there has been little improvement during the last decade and more selective and effective forms of treatment are urgently needed.

Acute Disease↗
PubMed1986

Surface immunoglobulin light chain expression in pre-B cell leukemias.

Cytofluorographic analysis of surface immunoglobulin (sIg) light chain clonal excess (CE), defined as (%kappa+ - %lambda+)/(%kappa+ + %lambda+) cells per discrete level of fluorescence intensity, was carried out on mononuclear cells of 32 leukemic patients. Eight demonstrated sIg light chain CE, including four blastic chronic myeloid leukemias (BL-CML), three "null" acute lymphoblastic leukemias (ALL), and one leukemic lymphoblastic lymphoma. Six of the leukemias demonstrated a kappa CE and two had a lambda CE. Sorted kappa+ PB cells from a BL-CML patient were shown to have a diploid DNA stem line and to bear the "common" ALL antigen. To provide further support for our finding of the expression of sIg light chains in ALL, we studied the REH cell line, derived from a "common" ALL patient and found cytoplasmic mu heavy chain and surface Ig lambda CE. Nucleic acid blotting experiments on REH revealed that both kappa genes had been deleted and that lambda genes had been rearranged, as expected in B cells expressing lambda light chains. Moreover, REH cells contained mu and lambda RNA. When REH cells were treated with TPA the amount of mu chain RNA increased by approximately fivefold and the amount of lambda chain RNA increased by approximately twofold. The finding of sIg light chain in pre-B cell leukemias and in the REH cell line, suggests that these leukemic cells are further differentiated along the B-cell lineage than was previously believed.

Antigens, Neoplasm↗
PubMed1986

Comparison of the cytotoxic effects of merocyanine-540 on leukemic cells and normal human bone marrow.

Various chemical compounds have been described to induce photosensitization of tumor cells resulting in cell death. We studied the effect of merocyanine-540 (MC-540) on both leukemic and normal bone marrow (BM) cells. Acute promyelocytic leukemia (HL-60) and common acute lymphoblastic leukemia antigen-positive non-T, non-B acute lymphoblastic leukemia (Reh) cell lines were incubated with MC-540 and simultaneously exposed to white light. Normal human BM and mixtures of leukemic cells with BM cells were treated under similar conditions. At constant illumination rates of 50,000 lx, significant (at least 4 to 5 logs) tumor cell destruction was obtained with MC-540 concentrations of 20 micrograms/ml or more for HL-60, and 10 micrograms/ml or more for Reh cells. Incubation of BM under equivalent conditions preserved 18.0% of granulocyte-macrophage colony-forming units and 14.2% of erythroid burst-forming units. Similar results were obtained when tumor cells were mixed with irradiated BM and then treated with MC-540. In summary, cell photosensitization with MC-540 has a selective cytotoxic effect towards leukemic cells and therefore may be useful for purging tumor cells from autologous BM.

Bone Marrow↗
PubMed1985

Hairy cell leukemia. Durability of response to splenectomy in 26 patients and treatment of relapse with androgens in six patients.

Twenty-three of 26 patients with hairy cell leukemia evaluable for response to splenectomy had significant improvement in anemia, thrombocytopenia, and/or neutropenia. Eight of the 23 had a recurrence of cytopenia after a median response duration of 4 to 5 months (range, 1-22). The remaining 15 patients did not have a recurrence of cytopenia at 20 months median follow-up (range, 1-76). Six patients with postsplenectomy cytopenia were given androgenic steroids. Two of the six had an improvement in anemia and thrombocytopenia, and a third patient had an improvement in neutropenia. It was concluded that, although most patients with hairy cell leukemia have initial improvement in cytopenia with splenectomy, a significant number of them either fail to respond or have recurrent cytopenia after initial response to splenectomy. A trial of androgenic steroids is a reasonable therapeutic option in these patients. Alternative therapies are reviewed and recommendations made.

Adult↗
PubMed1985

13-cis-Retinoic acid does not increase the true remission rate and the duration of true remission (induced by cytotoxic chemotherapy) in patients with chronic phase chronic myelogenous leukemia.

Treatment of chronic phase chronic myelogenous leukemia with hydroxyurea or busulfan rarely induces cytogenetic (true) remissions. Intensive chemotherapy induces brief true remissions in approximately 50% of patients. We added 13-cis-retinoic acid to daunorubicin, cytosine arabinoside, and thioguanine to determine if it could increase the incidence and duration of remission induced by cytotoxic chemotherapy. Of the 17 evaluable patients, one patient (6%) achieved complete remission, and seven patients (41%) achieved partial remissions. The median duration of remission was 1.6 months. We conclude that 13-cis-retinoic acid does not increase the incidence and duration of remission in chronic phase chronic myelogenous leukemia.

Adolescent↗
PubMed1985

Synergistic effect of 4-hydroperoxycyclophosphamide and etoposide on a human promyelocytic leukemia cell line (HL-60) demonstrated by computer analysis.

Autologous stem cell transplantation using cryopreserved bone marrow offers the opportunity to rescue patients from hematopoietic toxicity caused by intensive chemotherapy. This approach is potentially useful for high-risk leukemias as well as for other cancers. The development of suitable methods for purging malignant cells from the bone marrow will offer a better chance of success for autologous stem cell transplantation. In this paper, we describe our efforts at purging myeloid cells. HL-60, a promyelocytic leukemia cell line, was used as a model. 4-Hydroperoxycyclophosphamide (4-HC) and VP-16-213 (VP-16) (either alone or in combination) were used to treat HL-60 cells and normal bone marrow. The cytotoxic effect of 4-HC (29.2 micrograms/ml; 100 microM) upon the HL-60 cell line was 99.8 +/- 0.12% (SE), and the colony-forming units-granulocyte, macrophage (CFU-cs) of normal bone marrow was inhibited by 82.5%. VP-16, at a concentration of 25 micrograms/ml (42.5 microM), can kill 99% of HL-60 cells and inhibit 72.7% of the CFU-cs. A drug mixture containing 4-HC (29.2 micrograms/ml) and VP-16 (10 micrograms/ml) (combination ratio, 1:0.342) reduces HL-60 cells to an undetectable number, and the CFU-cs were inhibited by 87.2%. The laboratory data were further analyzed for the synergistic effect of these two drugs by quantitative determination of the median effect plot and the multiple drug equation recently described by Chou and Talalay (Adv. Enz. Regul., 22: 27-55, 1984). Interactions of two drugs at different effect levels and at different combination ratios were then determined by computer simulation. At high effect levels, 4-HC and VP-16 in combination gave a synergistic cytocidal effect on HL-60 leukemic cells and gave an antagonistic inhibitory effect on normal bone marrow CFU-cs. This combination greatly increases the safety margin. Computer simulation of a dose effect relationship has also shown that the 4-HC:VP-16 combination ratio of 1:0.342 yields a better selective effect than a ratio of 1:0.856. This quantitative analysis suggests that the combination of these two drugs at the selected dose level offers a good method for purging nonlymphoblastic leukemia cells.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Effects of in vitro purging with 4-hydroperoxycyclophosphamide on the hematopoietic and microenvironmental elements of human bone marrow.

UNLABELLED: We describe the effects of 4-hydroperoxycyclophosphamide (4-HC) on the hematopoietic and stromal elements of human bone marrow. Marrow cells were exposed to 4-HC and then assayed for mixed (CFU-Mix), erythroid (BFU-E), granulomonocytic (CFU-GM), and marrow fibroblast (CFU-F) colony-forming cells and studied in the long-term marrow culture (LTMC) system. The inhibition of colony formation by 4-HC was dose and cell-concentration dependent. The cell most sensitive to 4-HC was CFU-Mix (ID50 31 mumol/L) followed by BFU-E (ID50 41 mumol/L), CFU-GM (ID50 89 mumol/L), and CFU-F (ID50 235 mumol/L). In LTMC, a dose-related inhibition of CFU-GM production was noted. Marrows treated with 300 mumol/L 4-HC were completely depleted of CFU-GM but were able to generate these progenitors in LTMC. Marrow stromal progenitors giving rise to stromal layers in LTMC, although less sensitive to 4-HC cytotoxicity, were damaged by 4-HC also in a dose-related manner. Marrows treated with 4-HC up to 300 mumol/L, gave rise to stromal layers composed of fibroblasts, endothelial cells, adipocytes, and macrophages. Cocultivation experiments with freshly isolated autologous hematopoietic cells showed that stromal layers derived from 4-HC-treated marrows were capable of sustaining the long-term production of CFU-GM as well as controls. IN CONCLUSION: (1) Hematopoietic progenitors cells, CFU-Mix, BFU-E, and CFU-GM, are highly sensitive to 4-HC, whereas marrow stromal progenitor cells are relatively resistant. (2) Marrows treated with 300 mumol/L 4-HC that are depleted of CFU-Mix, BFU-E, and CFU-GM can generate CFU-GM in LTMC, suggesting that most primitive hematopoietic stem cells (not represented by CFU-Mix) are spared by 4-HC up to this dose. (3) Consequently, the above colony assays are not suitable tools for predicting pluripotent stem cell survival after 4-HC treatment in vitro.

Bone Marrow↗
PubMed1984

Leukemia following treatment of germ cell tumors in men.

We investigated the incidence of leukemia occurring subsequent to the treatment of germ cell tumors in men at our institution over a 30-year interval and found four patients with acute nonlymphocytic leukemia (ANLL) and one patient with chronic myelomonocytic leukemia. The relative risk (observed/expected cases) estimates for the development of leukemia ranged from 13.7 (P = .0005) in the total population to 50.1 (P = .0001) in the group treated with cytotoxic agents alone. All three patients with ANLL treated with contemporary antileukemic therapy had complete responses, with survivals of 7, 29, and 133 + months. In a review of the literature, 14 additional cases of germ cell tumors were found in which the men subsequently developed leukemia. It is concluded that leukemia following germ cell tumors is increased in incidence and is likely to be treatment induced. Complete responses and long-term survival are possible in secondary leukemia and aggressive antileukemic therapy should be given.

Adult↗
PubMed1984

Treatment of immunodeficiency with interleukin-2: initial exploration.

Fifteen patients with acquired immunodeficiency syndrome (AIDS), lymphoma and immunodeficiency, or severe combined immunodeficiency were treated with highly purified interleukin-2 (IL-2) prepared from human lymphocytes. All patients showed a defect in mitogen-induced T cell proliferation which was partially corrected when IL-2 was added in vitro. IL-2 was administered subcutaneously by daily injection or continuous infusion. The maximum daily dose was 20,000 U/m2, the maximum total dose 855,000 U/m2, and the maximum period of treatment 77 days. An increase in the platelet count was seen in one patient with AIDS, a decrease in the serum level of a monoclonal immunoglobulin in another patient with AIDS, and a minor tumor response in a patient with diffuse histiocytic lymphoma. As no toxicity was observed, further study of IL-2 in the treatment of human immunodeficiency is indicated.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Prognostic discrimination in "good-risk" chronic granulocytic leukemia.

The prognostic significance of disease features recorded at the time of diagnosis was examined among 813 patients with Philadelphia chromosome-positive, nonblastic chronic granulocytic leukemia (CGL) collected from six European and American series. The survival pattern for this population was typical of "good-risk" patients, and median survival was 47 mo. There were multiple interrelationships among different disease features, which led to highly significant correlations with survival for some that had no primary prognostic significance, such as hematocrit. Multivariable regression analysis indicated that spleen size and the percentage of circulating blasts were the most important prognostic indicators. These features, and age, behaved as continuous variables with progressively unfavorable import at higher values. The platelet count did not influence survival significantly at values below 700 X 10(9)/liter but was increasingly unfavorable above this level. Basophils plus eosinophils over 15%, more than 5% marrow blasts, and karyotypic abnormalities in addition to the Ph1 were also significant unfavorable signs. The Cox model, generated with four variables representing percent blasts, spleen size, platelet count, and age, provided a useful representation of risk status in this population, with good fit between predicted and observed survival over more than a twofold survival range. A hazard function derived from half of the patient population successfully segregated the remainder into three groups with significantly different survival patterns. We conclude that it should be possible to identify a lower risk group of patients with a 2-yr survival of 90%, subsequent risk averaging somewhat less than 20%/yr and median survival of 5 yr, an intermediate group, and a high-risk group with a 2-yr survival of 65%, followed by a death rate of about 35%/yr and median survival of 2.5 yr.

Adolescent↗
PubMed1984

Thymidine as a kinetic and biochemical modulator of 1-beta-D-arabinofuranosylcytosine in human acute nonlymphocytic leukemia.

We have carried out a clinical trial in which patients with relapsed leukemia were treated with thymidine (dThd) prior to and concomitantly with the administration of 1-beta-D-arabinofuranosylcytosine (ara-C) in an effort to kinetically and biochemically modulate the leukemic cells with two objectives: (a) to increase the S-phase fraction before giving ara-C; and (b) to increase the uptake and phosphorylation of ara-C. Six patients with acute nonlymphocytic leukemia who had relapsed after conventional or experimental therapy were given continuous i.v. infusions of dThd in conjunction with ara-C. dThd was started at 75 g/sq m/day (producing 1 mM plasma levels) and was given for 5 to 8 days until the proportion of bone marrow cells in S-phase (measured by autoradiography and flow cytometry) had increased and/or stabilized; then ara-C at 200 mg/sq m/day was begun. Twenty-four hr after initiation of ara-C therapy, the dThd dose was reduced to 30 g/sq m/day (plasma dThd, 0.1 to 0.6 mM). Both drugs were continued for 6 to 12 days until marrow aplasia or unacceptable toxicity occurred. Four patients with a base-line labeling index lower than 30% experienced a sustained increase in the S-phase fraction; two patients with a base-line labeling index higher than 30% experienced a reduction in the S-phase compartment during dThd infusion, in one case followed by an increase. The degree of S-phase arrest did not correlate with remission induction. In 5 patients, the flash incorporation of labeled ara-C into nucleoside triphosphate and deoxycytidine into DNA of bone marrow cells was measured. Three patients had a significant increase in the incorporation of deoxycytidine into DNA. Two of them achieved a complete remission. Increases in ara-C uptake were less impressive. A new technique was used to measure the absolute number of blasts present in the bone marrow. A decrease in leukemic cells between 0.9 and 2.6 logs10/mm was found at the end of the infusions. Three patients experienced greater than 2-log reduction. Two of them entered complete remission that lasted 6 weeks and 3 months, respectively. These correlations should be interpreted with caution because of the small number of patients treated. This study suggests that dThd, although of very limited therapeutic value by itself, may have potentiated the antitumor activity of ara-C to some extent. Whether this effect is of significance can only be determined by further studies.

Acute Disease↗
PubMed1984

Effect of very high-dose thymidine infusions on leukemia and lymphoma patients.

The physiological pyrimidine nucleoside thymidine (dThd) is cytotoxic to normal and neoplastic cells in culture that are exposed to concentrations in excess of 1 mM for prolonged periods. In order to explore the antileukemic potential of the compound, we have treated six patients with relapsed leukemia or lymphoma with marrow and blood involvement, by prolonged infusions of dThd, at dosages of 90 to 240 g/sq m/day for 14 to 29 days. Mean plasma dThd concentration ranged from 3.8 to 5.5 mM. Cerebrospinal fluid levels were measured on three occasions and ranged from 2 to 23.5% of simultaneous plasma levels. Diarrhea was dose limiting in one patient. The other side effects included nausea and vomiting in all patients, hepatotoxicity in two patients, electrolyte imbalance in one, progression of a pericardial effusion to tamponade in one, and mild central nervous system toxicity in five. In all cases, this therapy produced bone marrow aplasia. One patient with acute lymphoblastic leukemia, refractory to prior treatment, achieved a complete remission which lasted for 16 weeks. Another patient with lymphoblastic lymphoma had a greater than 50% reduction in his mediastinal mass which lasted for less than 1 month. At multiple points during therapy, the bone marrow S-phase fraction was measured by flow cytometry and autoradiography. In five patients, the proportion of cells in S phase increased during the first few days of the infusion but then returned to base line, concomitant with an overall reduction in the number of bone marrow blasts. Cytoreduction was evaluated by the technique of W. Hiddemann, B. D. Clarkson, T. Buchener, M. R. Melamed, and M. Andreeff (Blood, 59: 216-225, 1982). The magnitude of tumor cell kill ranged from 0.7 to 3.6 logs of blasts/cu mm of bone marrow. The data demonstrate that dThd is able to induce a complete remission in a patient with acute leukemia previously refractory to treatment. However, because of the very large drug quantities, fluid volumes, and the prolonged course required to produce the necessary tumor cell kill, this treatment approach is too impractical to be used extensively.

Adult↗
PubMed1983

The non-Hodgkin's lymphomas. I. A retrospective clinical and pathologic analysis of 499 cases diagnosed between 1958 and 1969.

A retrospective clinical and histopathological review was made of 499 previously untreated cases of non-Hodgkin's lymphoma with adequate initial biopsy material diagnosed at Memorial Hospital between 1958 and 1969. Three hundred-eighty-four cases (77%) had diffuse, 104 (21%) nodular, nine (2%) nodular and diffuse, and two (less than 1%) unclassifiable histologic types. Overall median survival was 16 months, and 79% of the patients died with lymphoma. For all treatments, survival of responding patients was the same as that of nonresponders, a reflection of the palliative approach. Significant differences in survival were found between patients in the various Ann Arbor stages. Median survival was 42 months for the nodular group and 11.5 months for the diffuse (P less than 0.001). The ten-year survival was 12% for the diffuse and 22% for the nodular patients. The overall difference in survival was due to early deaths in the diffuse group. Long-term follow-up is necessary to appreciate the usual fatal course of patients with all types of non-Hodgkin's lymphomas treated conservatively.

Adolescent↗
PubMed1983

Combination chemotherapy for the treatment of Hodgkin's disease in relapse. Results with lomustine (CCNU), melphalan (Alkeran), and vindesine (DVA) alone (CAD) and in alternation with MOPP and doxorubicin (Adriamycin), bleomycin, and vinblastine (ABV).

Vindesine (desacetyl vinblastine amide sulfate, DVA) was used in combination with CCNU (lomustine) and melphalan (Alkeran) (CAD) to treat 15 heavily pretreated patients with Hodgkin's disease in relapse. The patients were treated with up to six cycles, depending upon their response. Two patients (13%) achieved a complete remission (CR) and five (33%) patients a partial remission (PR). The major toxicity was prolonged thrombocytopenia, which was decreased by a reduction in the initial drug doses for patients who had received extensive prior chemotherapy and radiotherapy (RT). The CAD regimen was then alternated with nitrogen mustard or cyclophosphamide, vincristine, procarbazine, and prednisone (MOPP, C-MOPP) and doxorubicin (Adriamycin), bleomycin, and vinblastine (ABV) for a total of nine cycles in 25 patients with Hodgkin's disease in relapse with somewhat more favorable prognostic features. Two patients also received low-dose RT to areas of bulky nodal disease. Eleven patients (44%) achieved a CR and seven (28%) a PR. Of the 11 CR patients, six remain in remission. The serious toxicity was comparable to that seen with other combination chemotherapy regimens. These results indicated that the CAD/MOPP/ABVD regimen is as active as other so-called 'salvage' regimens for Hodgkin's disease in relapse, and suggest that it might be useful for newly diagnosed Hodgkin's disease.

Adolescent↗
PubMed1983

Unfractionated human marrow cell cryopreservation using dimethylsulfoxide and hydroxyethyl starch.

Unfractionated bone marrow (BM) cells were cryopreserved in 1- to 2-ml aliquots using a mixture containing both 5% dimethylsulfoxide (DMSO) and 6% hydroxyethyl starch (HES) in an attempt to increase the viable cell yield and reduce the clumping after thawing, observed when 10% DMSO is used alone. Samples thawed after storage for 6 months in the vapor phase of liquid nitrogen, were assayed. Compared to prefreeze values, there was both a greater number of cells that excluded Trypan Blue (50 +/- 12 vs 28 +/- 12%, P less than .01) and a greater CFU-C Recovery (110 +/- 20 vs 89 +/- 35%, P less than .02) for cells in the DMSO/HES mixture, compared to those in 10% DMSO alone. No macroscopic clumping of the thawed cells was observed for those cryopreserved in the mixture in contrast to those in DMSO alone. Freezing was done without a rate-controlled freezing apparatus by simply placing the samples initially into a -80 degrees C freezer, and then later into a liquid nitrogen freezer. Additional samples stored in the DMSO/HES mixture were kept at only -80 degrees C, and when thawed 12 to 16 months later also gave an excellent CFU-C recovery (105 +/- 39% of prefreeze). The DMSO/HES mixture allows for a simplified BM cryopreservation technique that not only assures excellent recovery of CFU-Cs and eliminates clumping upon thawing, but also does not require either the use of a rate-controlled freezer or liquid nitrogen temperatures for storage up to a year.

Bone Marrow Cells↗