[Effect of wheat-grain moxibustion on Wnt/ß-catenin signaling pathway in bone marrow cell in mice with bone marrow inhibition].

OBJECTIVE: To observe the effect of wheat-grain moxibustion at "Dazhui" (GV 14), "Zusanli" (ST 36) and "Sanyinjiao" (SP 6) on Wnt/ß-catenin signaling pathway in bone marrow cell in mice with bone marrow inhibition, and to explore the possible mechanism of wheat-grain moxibustion in treating bone marrow inhibition. METHODS: Forty-five SPF male CD1(ICR) mice were randomly divided into a blank group, a model group and a wheat-grain moxibustion group, 15 mice in each group. The bone marrow inhibition model was established by intraperitoneal injection of 80 mg/kg of cyclophosphamide (CTX). The mice in the wheat-grain moxibustion group were treated with wheat-grain moxibustion at "Dazhui" (GV 14), "Zusanli" (ST 36) and "Sanyinjiao" (SP 6), 3 moxa cones per acupoint, 30 s per moxa cone, once a day, for 7 consecutive days. The white blood cell count (WBC) was measured before modeling, before intervention and 3, 5 d and 7 d into intervention. After intervention, the general situation of mice was observed; the number of nucleated cells in bone marrow was detected; the serum levels of interleukin-3 (IL-3), interleukin-6 (IL-6) and granulocyte macrophage colony stimulating factor (GM-CSF) were measured by ELISA; the protein and mRNA expression of ß-catenin, cyclinD1 and C-Myc in bone marrow cells was measured by Western blot and real-time PCR method. RESULTS: Compared with the blank group, the mice in the model group showed sluggish reaction, unstable gait, decreased body weight, and the WBC, number of nucleated cells in bone marrow as well as serum levels of IL-3, IL-6, GM-CSF were decreased (P<0.01), and the protein and mRNA expression of ß-catenin, cyclinD1 and C-Myc was decreased (P<0.01). Compared with the model group, the mice in the wheat-grain moxibustion group showed better general condition, and WBC, the number of nucleated cells in bone marrow as well as serum levels of IL-3, IL-6, GM-CSF were increased (P<0.01, P<0.05), and the protein and mRNA expression of ß-catenin, cyclinD1 and C-Myc was increased (P<0.05). CONCLUSION: Wheat-grain moxibustion shows therapeutic effect on bone marrow inhibition, and its mechanism may be related to activating Wnt/ß-catenin signaling pathway in bone marrow cells, improving bone medullary hematopoiesis microenvironment and promoting bone marrow cell proliferation.

Effect of wheat-grain moxibustion on Wnt/β-catenin signaling pathway in bone marrow cell in mice with bone marrow inhibition / 中国针灸

OBJECTIVE@#To observe the effect of wheat-grain moxibustion at "Dazhui" (GV 14), "Zusanli" (ST 36) and "Sanyinjiao" (SP 6) on Wnt/β-catenin signaling pathway in bone marrow cell in mice with bone marrow inhibition, and to explore the possible mechanism of wheat-grain moxibustion in treating bone marrow inhibition.@*METHODS@#Forty-five SPF male CD1(ICR) mice were randomly divided into a blank group, a model group and a wheat-grain moxibustion group, 15 mice in each group. The bone marrow inhibition model was established by intraperitoneal injection of 80 mg/kg of cyclophosphamide (CTX). The mice in the wheat-grain moxibustion group were treated with wheat-grain moxibustion at "Dazhui" (GV 14), "Zusanli" (ST 36) and "Sanyinjiao" (SP 6), 3 moxa cones per acupoint, 30 s per moxa cone, once a day, for 7 consecutive days. The white blood cell count (WBC) was measured before modeling, before intervention and 3, 5 d and 7 d into intervention. After intervention, the general situation of mice was observed; the number of nucleated cells in bone marrow was detected; the serum levels of interleukin-3 (IL-3), interleukin-6 (IL-6) and granulocyte macrophage colony stimulating factor (GM-CSF) were measured by ELISA; the protein and mRNA expression of β-catenin, cyclinD1 and C-Myc in bone marrow cells was measured by Western blot and real-time PCR method.@*RESULTS@#Compared with the blank group, the mice in the model group showed sluggish reaction, unstable gait, decreased body weight, and the WBC, number of nucleated cells in bone marrow as well as serum levels of IL-3, IL-6, GM-CSF were decreased (P<0.01), and the protein and mRNA expression of β-catenin, cyclinD1 and C-Myc was decreased (P<0.01). Compared with the model group, the mice in the wheat-grain moxibustion group showed better general condition, and WBC, the number of nucleated cells in bone marrow as well as serum levels of IL-3, IL-6, GM-CSF were increased (P<0.01, P<0.05), and the protein and mRNA expression of β-catenin, cyclinD1 and C-Myc was increased (P<0.05).@*CONCLUSION@#Wheat-grain moxibustion shows therapeutic effect on bone marrow inhibition, and its mechanism may be related to activating Wnt/β-catenin signaling pathway in bone marrow cells, improving bone medullary hematopoiesis microenvironment and promoting bone marrow cell proliferation.

Day 14 Bone Marrow Evaluation During Acute Myeloid Leukemia Induction in a Real-world Canadian Cohort.

INTRODUCTION: The 2017 National Comprehensive Cancer Network guidelines for acute myeloid leukemia have recommended performing bone marrow (BM) aspiration and BM trephine biopsy (BMTB) 14 to 21 days after starting induction therapy (commonly referred to as "day 14 [D14] marrow"). Those who do not achieve a hypoplastic marrow, with cellularity < 20% and blasts < 5%, are recommended to undergo 2-cycle induction (2CI). We performed a retrospective analysis to determine the impact of D14 BM characteristics in predicting for remission, association with overall survival (OS), and the effect of 2CI according to the D14 BM results. PATIENTS AND METHODS: Patients aged 18 to 70 years undergoing induction therapy with standard "7 + 3" regimens were included. D14 cellularity was determined from BMTB samples and the blast percentage was assessed by morphology on BM aspiration and BMTB samples. The outcomes evaluated included the rates of complete remission (CR) and OS. RESULTS: A total of 486 patients with results from D14 BM evaluation were included in the present study. On multivariate analysis, cytogenetic risk and D14 blasts < 5% were predictive of CR/CR with incomplete count recovery (P < .001). Cytogenetic risk (P < .001), age < 60 years (P = .001), and D14 blasts < 5% (P = .045) predicted for OS. 2CI was performed in 131 patients (27%). Patients with hypocellular D14 BM but residual blasts (n = 106) underwent 2CI in 46% of cases, with improved remission rates (43.9% vs. 72.0%; P = .004) but no difference in OS. CONCLUSIONS: The results from D14 BM evaluations are predictive of subsequent remission and OS. Our findings did not show a survival benefit with D14 BM-driven 2CI.

[The effect of low frequency electrical stimulation on bone tissue regeneration].

The study was performed on 30 male rats of Wistar line (weight 330-360 g, age 3.5 months).In an experimental model of damage to the femur bone in the hip joint studied the effect of low frequency electrical stimulation of the damaged area on the rate of regeneration of bone. The animals were divided into two groups. Control (15 rats) and experienced (15 rats). In the experimental animals underwent stimulation of the injury site for 5 min daily for 7 days, 14 days and 21 days. Stimulation was carried out using a device "Osteon-1" generating a mixed signal of two voltage pulse of varying duty cycle, one of which is modulated to a higher frequency. Signals were not synchronized with respect to each other, unipolar with varying frequencies and amplitudes. The obtained results show the effectiveness of the electrical stimulation currents of low frequency in the restoration of bone tissue after damage. Morphological studies showed that electrical stimulation to accelerate the regeneration of damaged bone at all stages of the study (7, 14, 21 day), causes a more pronounced integration of newly formed bone with the old intact bone and promote the formation of more powerful periosteal calluses in comparison with the control.

Bone marrow from blotchy mice is dispensable to regulate blood copper and aortic pathologies but required for inflammatory mediator production in LDLR-deficient mice during chronic angiotensin II infusion.

BACKGROUND: The blotchy mouse caused by mutations of ATP7A develops low blood copper and aortic aneurysm and rupture. Although the aortic pathologies are believed primarily due to congenital copper deficiencies in connective tissue, perinatal copper supplementation does not produce significant therapeutic effects, hinting additional mechanisms in the symptom development, such as an independent effect of the ATP7A mutations during adulthood. METHODS: We investigated if bone marrow from blotchy mice contributes to these symptoms. For these experiments, bone marrow from blotchy mice (blotchy marrow group) and healthy littermate controls (control marrow group) was used to reconstitute recipient mice (irradiated male low-density lipoprotein receptor -/- mice), which were then infused with angiotensin II (1,000 ng/kg/min) for 4 weeks. RESULTS: By using Mann-Whitney U test, our results showed that there was no significant difference in the copper concentrations in plasma and hematopoietic cells between these 2 groups. And plasma level of triglycerides was significantly reduced in blotchy marrow group compared with that in control marrow group (P < 0.05), whereas there were no significant differences in cholesterol and phospholipids between these 2 groups. Furthermore, a bead-based multiplex immunoassay showed that macrophage inflammatory protein (MIP)-1ß, monocyte chemotactic protein (MCP)-1, MCP-3, MCP-5, tissue inhibitor of metalloproteinases (TIMP)-1, and vascular endothelial growth factor (VEGF)-A production was significantly reduced in the plasma of blotchy marrow group compared with that in control marrow group (P < 0.05). More important, although angiotensin II infusion increased maximal external aortic diameters in thoracic and abdominal segments, there was no significant difference in the aortic diameters between these 2 groups. Furthermore, aortic ruptures, including transmural breaks of the elastic laminae in the abdominal segment and lethal rupture in the thoracic segment, were observed in blotchy marrow group but not in control marrow group; however, there was no significant difference in the incidence of aortic ruptures between these 2 groups (P = 0.10; Fisher's exact test). CONCLUSIONS: Overall, our study indicated that the effect of bone marrow from blotchy mice during adulthood is dispensable in the regulation of blood copper, plasma cholesterol and phospholipids levels, and aortic pathologies, but contributes to a reduction of MIP-1ß, MCP-1, MCP-3, MCP-5, TIMP-1, and VEGF-A production and triglycerides concentration in plasma. Our study also hints that bone marrow transplantation cannot serve as an independent treatment option.

Hypoxia-induced endothelial dysfunction in apolipoprotein E-deficient mice; effects of infliximab and L-glutathione.

OBJECTIVE: Obstructive sleep apnoea (OSA) has been implicated as a risk factor for atherosclerosis. The aim of our study was to examine the effects of chronic intermittent hypoxia in apoE-/- mice serving as model of OSA on endothelial dysfunction and oxidative stress and to evaluate the reversibility of hypoxia-induced changes under anti-inflammatory infliximab and anti-oxidative l-glutathione. METHODS: ApoE-/- mice were divided into 4 groups (n = 9 each): 1. intermittent hypoxia 8 h/day for 6 weeks, 2. intermittent hypoxia + injections of infliximab, 3. intermittent hypoxia + injections of l-glutathione, 4. normoxia = control. RESULTS: Endothelial function was impaired under hypoxia compared to control. Application of infliximab and l-glutathione improved it to a level of control. The percentage of endothelial microparticles increased under hypoxia compared to other groups. Levels of NADPH oxidase 2-derived reactive oxygen species were approximately 9 times higher in the hypoxia group. The number of sca-1/flk-1+ endothelial progenitor cells was higher in bone marrow and lower in blood under hypoxia vs. other groups. Stromal cell derived factor-1alpha- and matrix metalloproteinase-9-dependent release of these cells from bone marrow was attenuated under hypoxia. The number of DilacLDL+/lectin + early outgrowth progenitor cells and that of colony forming units from these cells were higher under hypoxia. Atherosclerotic plaques in the aorta were more frequent under hypoxia and control in comparison with both drug groups. CONCLUSION: Intermittent hypoxia contributes to endothelial dysfunction by the local increase in reactive oxygen species and reduction of the peripheral repair capacity. Infliximab and l-glutathione prevent hypoxia-induced vascular and extravascular changes.

[Establishment of an mouse model of iron-overload and its impact on bone marrow hematopoiesis].

OBJECTIVE: To establish a mouse model of iron overload by intraperitoneal injection of iron dextran and investigate the impact of iron overload on bone marrow hematopoiesis. METHODS: A total of 40 C57BL/6 mice were divided into control group, low-dose iron group (12.5 mg/ml), middle-dose iron group (25 mg/ml), and high-dose iron group (50 mg/ml). The control group received normal saline (0.2 ml), and the rest were injected with intraperitoneal iron dextran every three days for six weeks. Iron overload was confirmed by observing the bone marrow, hepatic, and splenic iron deposits and the bone marrow labile iron pool. In addition, peripheral blood and bone marrow mononuclear cells were counted and the hematopoietic function was assessed. RESULTS: Iron deposits in bone marrow, liver, and spleen were markedly increased in the mouse models. Bone marrow iron was deposited mostly within the matrix with no significant difference in expression of labile iron pool.Compared with control group, the ability of hematopoietic colony-forming in three interventional groups were decreased significantly (P<0.05). Bone marrow mononuclear cells counts showed no significant difference. The amounts of peripheral blood cells (white blood cells, red blood cells, platelets, and hemoglobin) in different iron groups showed no significant difference among these groups;although the platelets were decreased slightly in low-dose iron group [(780.7±39.60)×10(9)/L], middle dose iron group [(676.2±21.43)×10(9)/L], and high-dose iron group [(587.3±19.67)×10(9)/L] when compared with the control group [(926.0±28.23)×10(9)/L], there was no significant difference(P>0.05). CONCLUSIONS: The iron-overloaded mouse model was successfully established by intraperitoneal administration of iron dextran. Iron overload can damage the hepatic, splenic, and bone marrow hematopoietic function, although no significant difference was observed in peripheral blood count.

Evaluation of (anti)genotoxic activities of Phyllanthus niruri L. in rat bone marrow using the micronucleus test

Phyllanthus niruri L. (Euphorbiaceae), known as "quebra-pedra" (Portuguese for "stonebreaker"), is an herb used for kidney disorders. In light of its frequent use by the population, the present study aimed to investigate the genotoxic, antigenotoxic and cytotoxic activities of a standardized P. niruri extract in bone marrow rats. Three groups of 12 animals were treated daily by gavage over a period of 30 days, with 50, 150 or 250 mg/kg of P. niruri extract aqueous solution. The control group (n = 12) received tap water. At the end of treatment (day 31), groups were divided into two minor subgroups (n=6/group) and received cyclophosphamide (50 mg/kg, i.p.) or saline 0.9% (i.p.). After 24 hours, we evaluated the frequency of micronucleated polychromatic erythrocytes for each animal (MNPCE) at 1000 PCE. Cytotoxicity was evaluated with the PCE/NCE ratio (NEC = normochromatic erythrocytes). General toxicity was assessed during treatment using the parameters of body weight gain, ration and water consumption. The dry extract did not provoke changes in body weight, weight gain, ration and water intake or changes in the frequency of MNPCE or cytotoxicity in bone marrow. We propose that the P. niruri extract used here showed no genotoxic, antigenotoxic and cytotoxic activities under the experimental conditions.

Phyllanthus niruri L. (Euphorbiaceae), conhecida como "quebra-pedra", é uma planta medicinal utilizada frequentemente pela população no tratamento de problemas renais. Foram avaliadas as atividades genotóxicas, antigenotóxicas e citotóxicas de um extrato padronizado dessa espécie em ratos. Três grupos de doze animais foram tratados durante trinta dias, por gavagem, com 50, 150 ou 250 mg/kg/dia de solução aquosa do extrato de P. niruri e um grupo controle (n=12) recebeu água destilada pela mesma via. No final do tratamento os grupos foram divididos em dois subgrupos (6 animais/grupo) e receberam uma dose única de ciclofosfamida (50 mg/kg, i.p.) ou de solução salina 0,9% (i.p.). Após 24 horas, a frequência de eritrócitos policromáticos micronucleados (EPCMN) foi avaliada em 1000 EPC. A citotoxicidade foi avaliada pela relação entre eritrócitos policromáticos e normocromáticos (EPC/ENC) e a toxicidade geral foi avaliada através dos parâmetros de ganho de peso corporal, consumo de ração e ingestão hídrica. O extrato seco não provocou alterações significativas no peso corporal, ganho de peso e consumo de ração em relação ao grupo controle, nem alterações na frequência de EPCMN ou citotoxicidade em medula óssea. Dessa maneira, pode-se concluir que P. niruri não apresentou atividades genotóxica, antigenotóxica e/ou citotóxica nas condições experimentais executadas.

[Comparison of the clinical therapeutic effects between electroacupuncture and warming needle moxibustion for knee osteoarthritis of kidney deficiency and marrow insufficiency pattern/syndrome].

OBJECTIVE: To explore the actions of electroacupuncture (EA) and the warming needle moxibustion on knee osteoarthritis (KOA) of kidney deficiency and marrow insufficiency pattern/syndrome and compare the clinical effects between these two therapies. METHODS: Seventy-four cases of KOA were randomly divided into an electroacupuncture (EA) group and a warming needle moxibustion (WNM) group, 37 cases in each one. The acupoints were Dubi (ST 35), Neixiyan (EX-LE 4), Xuehai (SP 10), Zusanli (ST 36), Yanglingquan (GB 34), etc. In EA group, electric stimulation was given, 5 Hz, continuous wave. In the WNM group, warm needling technique was applied, 2 moxa cones on each acupoint in each time, three treatments a week. Totally, 4 weeks of treatment were required. The indicaices such as WOMAC score, illness severity index and systematic efficacy were adopted to evaluate the efficacy before treatment, 1 session and 2 sessions after treatment separately. RESULTS: The treatment in either group achieved the effectiveness. The cured and markedly effective rate was 64.7% (22/34) in EA group and was 40.0% (14/35) in WNM group, presenting statistically significant difference in comparison (P < 0.05). But the total effective rate did not indicate significance (P > 0.05). In EA group, the releasing effect of joint pain was obvious (P < 0.01). In the WNM group, the treatment was more advantageous at relieving joint stiffness (P < 0.01). There was no difference in the mean curative time between two groups (P > 0.05). CONCLUSION: Electroacupuncture and the warming needle moxibustion have their own advantages in the treatment of KOA of kidney deficiency and marrow insufficiency pattern/syndrome. Electroacupuncture is advantageous at analgesia and the warming needle moxibustion is at relieving joint stiffness. The total efficacy of electroacupuncture is superior to that of the warming needle moxibustion.

Emerging therapies for multiple myeloma.

Multiple myeloma (MM) is a clonal plasma cell malignancy clinically characterized by osteolytic lesions, immunodeficiency, and renal disease. There are an estimated 750,000 people diagnosed with MM worldwide, with a median overall survival of 3 - 5 years. Besides chromosomal aberrations, translocations, and mutations in essential growth and tumor-suppressor genes, accumulating data strongly highlight the pathophysiologic role of the bone marrow (BM) microenvironment in MM pathogenesis. Based on this knowledge, several novel agents have been identified, and treatment options in MM have fundamentally changed during the last decade. Thalidomide, bortezomib, and lenalidomide have been incorporated into conventional cytotoxic and transplantation regimens, first in relapsed and refractory and now also in newly diagnosed MM. Despite these significant advances, there remains an urgent need for more efficacious and tolerable drugs. Indeed, a plethora of preclinical agents awaits translation from the bench to the bedside. This article reviews the scientific rationale of new therapy regimens and newly identified therapeutic agents - small molecules as well as therapeutic antibodies - that hold promise to further improve outcome in MM.

Observations on after-effect duration of kidney-nourishing and marrow-replenishing therapy on 58 cases of Mediterranean anemia.

OBJECTIVE: To observe the after-effect duration of kidney-nourishing and marrow-replenishing therapy on Mediterranean anemia. METHODS: To observe the kidney-nourishing and marrow-replenishing therapy on 58 cases of Mediterranean anemia and the influence of various relative factors on the after-effect duration. RESULTS: The after-effect duration on 58 cases varied from 3-6 months, about 4 months on average, and was not influenced by sex, clinical types, genetic types, types of Mediterranean anemia and other factors. CONCLUSION: Kidney-nourishing and marrow-replenishing therapy used to treat Mediterranean anemia can not only produce good therapeutic effect during treatment but also keep after effect lasting for about 4 months, indicating that the therapy used to treat Mediterranean anemia has good clinical after effect.

Treatment of 37 patients with refractory idiopathic thrombocytopenic purpura by shengxueling.

OBJECTIVE: To explore the clinical effect and possible mechanism of Shengxueling (SXL), a Chinese medical preparation mainly consisting of ginseng saponins, in treating refractory idiopathic thrombocytopenic purpura (ITP). METHODS: The selected 69 patients with ITP were randomly assigned to two groups, the 37 patients in the treated group were treated orally by SXL with the dose for adult as 60 mg twice a day for two weeks. Then when no marked rise of platelet count after that, the dose would be doubled and administered for another two weeks. Then the dose could be gradually reduced to the initiative level in patients who responded to the treatment, and if they did not, the treatment was regarded as ineffective and be terminated. The 32 patients in the control group were treated with ampeptide elemente instead of SXL, 0.4 g each time three times a day in the first two weeks, and, if that was ineffective, 0.2 g would be added each time and 1.8 g would be administered a day for two more weeks. Four weeks' treatment was regarded as one therapeutic course for both groups and the observation lasted for two successive courses in patients showing positive reslonse. RESULTS: In the 37 patients in the treated group, markedly effective was obtained in 7 (19.0%), favorably effective in 15 (40.5%), improved in 5 (13.5%) and ineffective in 10 (27.0%), the total effective rate being 59.5%. The corresponding number in the 32 patients in the control group was 4 (12.5%), 6 (18.8%), 3 (9.4%), 19 (59.4%) and 31.3% respectively. Comparison showed the difference in therapeutic efficacy between the two groups was significant (P<0.05). CONCLUSION: SXL is a safe and effective preparation for treatment of ITP, showing an immediate effect which is obviously superior to that of ampeptide elemente with less adverse effect.

Iron overload in patients with myelodysplastic syndromes.

The myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell diseases characterized by ineffective hematopoiesis in one or more cell lines, resulting in insufficient bone marrow function. For most patients with MDS, supportive care by blood transfusions is still the mainstay of treatment. Especially in low-risk patients, anemia represents the major clinical problem, and many of these patients develop transfusional iron overload. This paper reviews the literature on transfusional iron overload in patients with MDS, looking at pathophysiology, evaluation, and treatment of the transfusional iron burden with desferrioxamine and oral chelators.

Effective and rapid treatment of painful localized transient osteoporosis (bone marrow edema) with intravenous ibandronate.

Localized transient osteoporosis (LTO; bone marrow edema syndrome) is a rare disorder of generally unknown etiology that is characterized by acute onset of disabling bone pain. Treatment options are currently limited and largely ineffective. The locally increased bone turnover and low bone mineral density (BMD) typical of LTO indicate a potential role for bisphosphonate therapy. Ibandronate, a potent nitrogen-containing bisphosphonate, has proven efficacy in the management of postmenopausal osteoporosis and corticosteroid-induced osteoporosis when administered as a convenient intermittent intravenous (i.v.) injection with a between-dose interval of 2 or 3 months. In a study of 12 patients with LTO, ibandronate was administered as an initial 4-mg i.v. dose with a second, optional injection of 2 mg at 3 months. Daily calcium and vitamin D supplements were provided. Pain was measured at baseline and at 1, 2, 3, and 6 months using a visual analog scale (VAS) of 1-10, and BMD was measured at baseline and 6 months. I.v. ibandronate provided rapid and substantial pain relief. The mean (SD) VAS score decreased from 8.4 (1.3) at baseline to 0.5 (0.7) at 6 months, at which time seven patients had achieved complete pain relief. At 6 months, mean lumbar spine BMD had increased by 4.0% (range -0.8 to 7.7%) in the overall population. I.v. ibandronate injection affords advantages over currently available oral and i.v. bisphosphonates and thus offers a promising therapeutic advance in the treatment of LTO.

[Morphological and functional characteristics of hemopoiesis during the combined use of cyclophosphane with millimeter-band radio waves of nonthermal intensity]. / Morfologicheskie i funktsional'nye osobennosti krovetvoreniia pri kombinirovannom ispol'zovanii tsiklofosfana s radiovolnami millimetrovogo diapazona neteplovoi intensivnosti.

Material is presented on combined effects of mm-band radio waves and cyclophosphane on the hemopoietic system and inoculated tumor sarcoma-180. The role of the bone marrow truncal cells in the acceleration of regenerative processes and a two-fold increase of clonogenic activity of the bone marrow were determined in the combined group in comparison with the bone marrow of animals receiving just the preparation. The sensitizing effect of mm-waves in combination with cyclophosphane was distinctly manifested after two courses of administration of the preparation, leading to 85-100% resorption of the tumours without further relapses during the year of observation over the animals.

Relationship of the growth of leukemic cells in vitro to the outcome of therapy for acute nonlymphocytic leukemia.

Bone marrow cells obtained from 166 patients with acute nonlymphocytic leukemia were cloned in vitro. The number and size of clones produced differed among patients and was unrelated to French-American-British type of leukemia, to patient age, to whether the patient was studied at the time of initial diagnosis or at relapse, or to the cytogenetic (normal or abnormal metaphases) or cell cycle characteristics of the leukemic bone marrow cells. The ability of leukemic cells to clone in vitro was associated with poor response to therapy in vivo, with the remission rate being inversely related to cloning efficiency of the leukemic cells, and with remission durations being inversely correlated with the size of the cluster/colonies formed in vitro. Only an occasional patient whose marrow cells produced clonal growth in vitro and in whom cytogenetic abnormalities were detected entered complete remission with conventional remission induction therapy. Measurement of the clonogenic potential in vitro of leukemic marrow cells together with their cytogenetic type may help to distinguish between patients who should and should not receive cytosine arabinoside/anthracycline antibiotic remission induction therapy and patients who do and do not require intensive remission consolidation chemotherapy.