人外周血内皮祖细胞的分离培养及鉴定

目的:从人外周血中分离培养内皮祖细胞(EPCs),并探讨其体外诱导培养的条件。方法:密度梯度离心法分离正常人外周血单个核细胞,置于鼠尾胶原包被的培养瓶中进行体外培养,流式细胞术和免疫荧光法检测分化细胞表面特异性抗原标记物的表达。结果:人外周血单个核细胞在鼠尾胶原包被的培养瓶中培养后呈梭形,并表达内皮细胞的特异性抗原CD34和KDR,和干/祖细胞抗原CD133。提示这些培养细胞既具有内皮细胞的表面标志和功能,又具有祖细胞特性。结论:成功从外周血中培养出EPCs。鼠尾胶原可取代EPCs培养中常用的纤维连接蛋白,是体外分离培养外周血EPCs的更节省的一种方法。     

人外周血内皮祖细胞的分离培养及鉴定

目的从人外周血中分离培养内皮祖细胞(EPCs),并探讨其体外诱导培养的条件.方法密度梯度离心法分离正常人外周血单个核细胞,置于鼠尾胶原包被的培养瓶中进行体外培养,流式细胞术和免疫荧光法检测分化细胞表面特异性抗原标记物的表达.结果人外周血单个核细胞在鼠尾胶原包被的培养瓶中培养后呈梭形,并表达内皮细胞的特异性抗原CD34和KDR,和干/祖细胞抗原CD133.提示这些培养细胞既具有内皮细胞的表面标志和功能,又具有祖细胞特性.结论成功从外周血中培养出EPCs.鼠尾胶原可取代EPCs培养中常用的纤维连接蛋白,是体外分离培养外周血EPCs的更节省的一种方法.     

Isolation of normal human megakaryocytes

S ummary . This paper reports a simple procedure for obtaining human megakaryocytes with a high purification and high recovery yield. Bone marrow cells, obtained from surgically removed ribs, were separated by a two-step procedure. Initially, a single cell suspension was enriched in megakaryocytes by equilibrium density centrifugation, the low density cell fraction was subsequently layered over a shallow continuous albumin gradient in a glass sedimentation chamber. Megakaryocytes averaged 0.03 ± 0.02% of all nucleated cells in the starting marrow cell suspension, after this procedure an average 80 ± 15% of the initial megakaryocyte population was recovered with a purity of 94 ± 4%. Previous methods, based upon the use of a two-step procedure, are reviewed. The theory of velocity sedimentation is discussed with regard to the differences in the methodology used, which account for the different results I obtained.     

Isolation of hemopoietic progenitor cells from human umbilical cord blood

A two-stage procedure to enrich hemopoietic progenitor cells from human umbilical cord blood is described. Mononuclear cells isolated from 60% Percoll gradients were first treated with a panel of monoclonal antibodies and complement to remove lymphoid and myeloid cells and granulocyte-macrophage colony-forming cells (CFU-GM) and their immature progeny. Cells stained with monoclonal antibody RFB-1 were separated on the fluorescence-activated cell sorter and cultured in the mixed-colony assay. Progenitor cells were isolated in a high RFB-1 antigen density cell fraction containing greater than 95% undifferentiated blast cells and 32% +/- 12% colony-forming cells. Pluripotential progenitor cells (CFU mix) were enriched 229-fold and accounted for 3.2% +/- 1.2% of the isolated cells. Erythroid progenitor cells (BFU-E) were enriched 204-fold and accounted for 20.8% +/- 8.4% of the isolated cells. The procedure recovered 114% +/- 32% of CFU mix but the number of CFU mix in unseparated cord blood appears to be underestimated due to the presence of granulocytic cells identified by monoclonal antibody CMRF-7 (CD15) that decrease the cloning efficiency of CFU mix. Removal of CD15+ cells yielded a four- to fivefold improvement in the plating efficiency of CFU mix. Mixed-colony formation was completed in 9-11 days in cultures inoculated with enriched progenitor cell fractions, compared with 14-16 days in cultures of unseparated cord blood. The enriched progenitor cells could be useful for studying the regulation of hemopoiesis by recombinant growth factors.     

Isolation of myeloid progenitor cells from peripheral blood of chronic myelogenous leukemia patients

Myeloid progenitor cells (colony- and cluster-forming cells in semisolid medium, CFU-GM) were purified from the peripheral blood of chronic myelogenous leukemia (CML) patients. Lymphocytes, monocytes, and most immature myeloid cells were simultaneously depleted with specific monoclonal antibodies using an erythrocyte rosette technique for cell separation. Cells expressing Ia-like antigen were then selected from the residual cell population. Day 7 CFU-GM were enriched 44--116-fold in the IA+ cell fraction, when compared to the unseparated cells, and up to 47% of the cells could form a myeloid colony or cluster in culture. This cell fraction contained up to 92% undifferentiated blasts, with the remainder mostly promyelocytes. The enriched CFU-GM cells were dependent on an exogenous supply of colony- stimulating factor for growth, and colony formation was linear with cell concentration over a large range (10(4)-10(1) cells/ml). This technique of rosette depletion and enrichment with specific monoclonal antibodies provides a unique method for purifying a homogenous population of myeloid precursor cells with defined surface antigen characteristics.     

Modulation of normal human erythropoietic progenitor cells in long-term liquid cultures after HIV-1 infection.

Long-term bone marrow cultures (LTBMC) have been infected by two isolates of human immunodeficiency virus type 1 (HIV-1) (HIV-1 LAV and HIV-1 NDK) at multiplicities of infection ranging from 10(2) to 2.10(6) tissue culture infectious units (TCIU) per 10(6) bone marrow mononuclear cells (BMMNC). These infected cells are nonproducer cells and the viruses can be rescued by coculture with peripheral blood lymphocytes, cord blood lymphocytes, or BMMNC and not by the CEM cell line. HIV-1 clearly is not cytopathic for these cells. Following production and growth of erythroid burst-forming units (BFU-E) and erythroid colony-forming units (CFU-E) for at least 6 weeks after infection with HIV-1 NDK, colony assays displayed a 50% inhibition of BFU-E production during 3 weeks of LTBMC. This was followed by a stimulation phase. On the contrary, HIV-1 LAV induces a 150% stimulation of BFU-E production, followed by 50% inhibition. Production of CFU-E was inhibited by 80-100% with the two isolates of HIV-1 after four weeks of LTBMC. Stimulatory and inhibitory activities were recovered from supernatants of infected LTBMC and lymphoid CEM cell lines, suggesting that HIV-1 induces release of a humoral factor responsible for disruption of hemopoietic progenitor cell production in vitro and consequently for hematologic abnormalities in AIDS patients.     

人外周血单个核细胞不同克隆成分向内皮祖细胞分化的实验研究

目的:探讨从成人外周血单个核细胞中分离、培养内皮祖细胞(EPCs)的方法以及EPCs的生物学特征。方法:密度梯度离心法获得单个核细胞,用含生长因子的内皮培养基接种于纤连蛋白包被的培养板中。细胞在接种后每2 h去除1次未黏附细胞共2次,然后隔日换液1次,7 d后计数早期克隆。每例血样均分为2等份,1份在获得早期克隆后进行下列实验;另1份持续培养直到晚期克隆出现进行相同实验。流式细胞技术检测细胞表面抗原表达,直接荧光染色法测定细胞结合荆豆凝集素及摄取乙酰化LDL,胶原凝胶细胞种植实验测定体外血管生成功能。结果:早期克隆中心为圆形细胞,周边是放射状排列的纺锤形细胞,再种植不能形成第2代克隆且无体外血管形成功能,细胞表面主要表达CD14和CD45。晚期克隆形态不同于早期克隆,在培养21～28 d间出现,再种植可形成第2代内皮细胞克隆,并能在胶原凝胶中形成管腔样结构。其构成细胞与早期克隆相比CD45、CD14表达显著减少(P<0.01)而CD146表达明显增加(P<0.01),2种克隆的构成细胞在结合植物凝集素和摄取乙酰化LDL方面未存在显著差异。结论:人外周血单个核细胞在内皮培养条件下可形成早期克隆和晚期克隆,早期克隆属于单核细胞系列,晚期克隆细胞具有EPCs的形态和生物学特征。     

Isolation of megakaryocytes from human placentae

Shedding of cytoplasm from circulating megakaryocytes (MKs) within the pulmonary vasculature suggests the lungs are an important site for normal platelet production. Fetal lungs receive only a minor fraction of the circulating blood volume. The placenta may act as a site for intrauterine platelet formation. Isolation of MKs from fetal vessels within the placenta has not been previously reported. Immediately after delivery, 3 human placentae were subjected to forward and retrograde perfusion across the placental capillary bed on the fetal side. MKs in perfusates were harvested by 'whole blood filtration' and identified by morphological and immunochemical methods. All perfusates yielded MKs. Qualitatively MKs with copious cytoplasm were more commonly found in perfusates collected from fetal arteries compared with those from fetal veins. This is consistent with filtration of MKs and fragmentation of their cytoplasm within the placental microcirculation to produce platelets. Perfusion of human placentae followed by filtration of perfusates is a useful technique for harvesting fetal MKs and permitting further elucidation of their physiological role.     

Isolation of leukaemia-associated inhibitor (LAI)-producing cells from normal peripheral blood

LAI, leukaemia-associated inhibitor, has previously been shown to be produced by a subpopulation of null cells in myeloid leukaemia, and has the capacity to suppress the proliferation of normal granulopoietic stem cells, CFU-GM, in vitro. In the present study, low density mononuclear cells from normal peripheral blood were separated into adherent/non-adherent, phagocytic/non-phagocytic, T-lymphocytes/non-T cells, and Fc-receptor positive and negative cells in search for LAI-producing cells in normal blood. Cell fractions enriched for NK-cells were isolated from Percoll gradients and NK-activity and LAI-production were assayed in the different fractions. Anti-Leu-2, anti-Leu-3, and anti-HLA-DR were used to deplete mononuclear cells of cells positive for these monoclonals using a panning technique. It is concluded from these studies that normal LAI-producing cells belong to a non-adherent, non-phagocytic, non-T, non-B, Fc-receptor positive population which does not express NK-activity, and which is Leu-2, Leu-3 and HLA-DR negative. The results imply that LAI may be a novel feedback regulator of the proliferative rate of granulopoietic stem cells and that LAI is produced by a small subpopulation of cells in both blood and bone marrow.     

从外周血单个核细胞中获得内皮祖细胞的方法学研究

目的 探讨从成人外周血单个核细胞中分离、培养内皮祖细胞(EPCs)的方法以及EPCs的生物学特征.方法 密度梯度离心法获得单个核细胞(MNCs),用含生长因子的内皮培养基接种于纤连蛋白包被的培养板中.分别采用常规方法(A组)和序列黏附法(B组)培养,A组细胞于接种第4天洗去未黏附细胞然后隔日换液1次;B组细胞接种后每2 h去除1次未黏附细胞,共2次.两组细胞均在7 d后计数早期克隆,持续培养直到晚期克隆出现.流式细胞技术检测细胞表面抗原表达,直接荧光染色法测定细胞结合荆豆凝集素及摄取乙酰化低密度脂蛋白,胶原凝胶细胞种植实验测定体外血管生成功能.结果 早期克隆数目的 获得在2组间差异有统计学意义,但序列黏附法获得晚期克隆数目显著增加(P＜0.05),且B组的早期克隆细胞表达CD3显著减少(P＜0.05).晚期克隆形态不同于早期克隆,在培养21～28 d出现,其组成细胞与早期克隆相比CD45、CD14表达显著减少(P＜0.001)而CD146表达明显增加(P＜0.01),只有晚期克隆再种植可形成第二代内皮细胞克隆,并具有体外血管生成功能.两种克隆的构成细胞在结合植物凝集素和摄取乙酰化低密度脂蛋白方面差异无统计学意义.结论 人外周血单个核细胞在内皮培养条件下可形成早期克隆和晚期克隆,早期克隆属于单核细胞系列,无内皮分化功能;晚期克隆细胞具有EPCs的形态和生物学特征,应用序列黏附法可显著提高晚期克隆获得率.     

A liquid culture method for the in vitro growth of hemopoietic progenitor cells from normal human adult peripheral blood allowing for analysis by multiparameter flow-cytometry.

A liquid culture method has been developed allowing for the in vitro growth of peripheral blood-derived hemopoietic progenitor cells of myeloid, erythroid, monocytic and megakaryocytic lineages. Adherent cell- and CD21-positive cell-depleted PBMC from normal subjects have been cultured in the presence of rhEPO, rhGM-CSF or rhIl-3. Culturing cells in liquid cultures and in plasma clots, a similar dose-response was observed for granulocytic cells/liquid culture and granulocytic colonies/plasma clot with rhGM-CSF, and also for erythroid cells/liquid culture and erythroid colonies/plasma clot with rhEPO. Comparing serum- liquid cultures to serum+ liquid cultures, the ratio of CD13+ cells to CD15+ cells was higher in serum- cultures, indicating a maturation arrest of myecloid cells with serum deprivation. Using dual-colour flow-cytometry, cell-cycle analysis of CD13+ cells, comparing the effects of rhGM-CSF to those of rhIl-3, have been performed. The liquid culture method promises to be a useful tool for the study of in vitro differentiation and proliferation of hemopoietic progenitor cells.     

Ex vivo expansion of mature human neutrophils with normal functions from purified peripheral blood CD34+ haematopoietic progenitor cells

Purified CD34+ haematopoietic progenitor cells were cultivated with stem cell factor, interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte CSF (G-CSF) for 7 d, and thereafter non-adherent cells were divided into two groups. Cells in one group (group A) were further cultivated for 7 d with four cytokines, and cells in the other group (group B) were further cultivated for 7 d with G-CSF alone. On day 14, 220-fold and 130-fold increases in the numbers of non-adherent cells were achieved for groups A and B respectively. These cell preparations contained 65% granulocytes for group A and 95% granulocytes for group B. These cells gained the ability to respond effectively with chemotaxis, phagocytosis and superoxide (O2-) release. Cells in group B were appropriately primed by G-CSF, GM-CSF, tumour necrosis factor alpha and IL-1beta for enhanced release of O2 -. The responsiveness of these cells was identical to that of peripheral blood neutrophils, indicating that cells in group B may be in the resting state. In contrast, cells in group A were not primed by these cytokines for enhanced release of O2- and released a large amount of O2- spontaneously, indicating that cells in group A may be in the activated state. These findings indicate that mature neutrophils with normal functions were expanded ex vivo in group B and suggest that these cells could be used for possible autologous neutrophil transfusion to prevent bacterial infections during severe neutropenia after cytotoxic chemotherapy.     

人脐静脉血内皮祖细胞的分离扩增和生物学特征

目的:探索人脐静脉血内皮祖细胞的分离和扩增条件,并观测其生物学特性.方法:采集人脐静脉血,应用密度梯度离心法,分离其中单个核细胞,流式细胞术检测CD133 CD34 阳性率;利用差速贴壁法(48 h内贴壁和48 h后贴壁)联合内皮细胞专用培养基EGM-2培养细胞,接种于预先包埋了明胶培养瓶或培养板,倒置显微镜观察细胞生长形态和形成集落能力,免疫细胞化学法检测其免疫表型,摄取Ac-LDL和连接UEA-1功能,在生长因子培养体系中诱导其向成熟内皮细胞分化.结果:所获单个核细胞中CD133 CD34 百分比为1.06%;在EGM-2培养体系下可获得2种亚型的内皮祖细胞,即早期内皮祖细胞和晚期增殖性内皮祖细胞.其中48h后贴壁细胞属于早期内皮祖细胞,增殖能力较弱,免疫荧光检测,显示CD14和CD34KDR胞浆呈阳性表达,Ac-LDL UEA-1 功能特征;而48 h内贴壁细胞在10～17 d时可见由单个细胞增殖形成的克隆,呈铺路石样单层排列,增殖力旺盛形成融合状态,形成次集集落;经免疫荧光检测,显示CD133CD34和CD34KDR细胞质呈阳性表达,Ae-LDL UEA-1 功能特征,传代后vWF,CD31呈强阳性表达,是晚期增殖性内皮祖细胞.结论:经人脐静脉血可分离培养获得2种亚型的内皮祖细胞,在特定的培养体系中细胞可由祖细胞表型向成熟内皮细胞分化.     

自外周血中获取内皮前细胞的方法

目的探讨自大鼠外周血中获取内皮前细胞（EPC）的方法。方法SD大鼠皮下注射粒细胞集落刺激因子（G-CSF）后抽取外周动脉血,密度梯度离心法获取单个核细胞,用完全培养液在体外培养后进行CD31、CD34、FLK-1和vWF免疫荧光染色,并检测其结合UEA-1、摄取acLDL的能力。结果将此方法收获的细胞进行CD31、CD34、FLK-1和vWF免疫荧光染色并检测其结合UEA-1、摄取ac-LDL的能力,证实为EPC。结论G-CSF刺激、密度梯度离心、完全培养液法可白大鼠外周血中获取较多EPC。     

Transplantation of enriched and purged peripheral blood progenitor cells from a single apheresis product in patients with non-Hodgkin's lymphoma

High-dose chemotherapy with or without radiotherapy followed by autologous transplantation of hematopoietic progenitor cells is an effective treatment for patients with high-risk or relapsed non- Hodgkin's lymphoma. Chemotherapy and/or hematopoietic growth factors have been used to mobilize progenitor cells in the peripheral blood for transplantation. However, the mobilized blood cell products have been found to be frequently contaminated with tumor cells, and techniques have not been developed to purge tumor cells from these products. In addition, the minimum number of hematopoietic progenitor cells required for engraftment has not yet been fully elucidated. We treated 21 patients with a single infusion of cyclophosphamide (4 g/m2) followed by daily administration of granulocyte colony-stimulating factor (G- CSF). After recovery of the white blood cell count, a single 3-hour apheresis collection was performed. The apheresis product was then applied to a discontinuous Percoll gradient. The low-density fractions resulting from this separation procedure were enriched for CD34+ progenitor cells (total cell yield, 19.5%; CD34+ cell recovery, 81.2%). These enriched cellular products were treated with a panel of anti-B cell or anti-T cell monoclonal antibodies and complement in an effort to remove residual tumor cells. After treatment of the patient with myeloablative therapies, the enriched and purged cells were reinfused. Hematologic recovery was rapid, with median neutrophil engraftment in 10 days [absolute neutrophil count (ANC), greater than 0.5 x 10(9)/L] and 11 days (ANC, greater than 1.0 x 10(9)/L). Median platelet transfusion independence required 13 days. The rapidity of multilineage engraftment correlated with the number of CD34+ cells per kilogram that were infused. Patients who received more than 2 x 10(6) CD34+ cells per kilogram had rapid hematologic engraftment, whereas those patients transplanted with less than 2 x 10(6) CD34+ cells per kilogram had slower platelet recovery. Modeling studies using a lymphoma cell line with a t(14; 18) chromosomal translocation demonstrated the successful removal of tumor cells assayed using the polymerase chain reaction (PCR) after the processing and purging. Four of the 21 patients had PCR- detectable lymphoma cells in the bone marrow and peripheral blood; however, the enriched and purged blood products reinfused in all four did not contain detectable tumor cells.(ABSTRACT TRUNCATED AT 400 WORDS)     

Transplantation of peripheral blood progenitor cells from HLA-identical sibling donors

Transplantation of peripheral blood progenitor cells (PBPCs) has largely replaced autologous bone marrow transplantation. The same might occur in the allogeneic setting if the favourable initial experience with allogeneic PBPCT is confirmed. We analysed all primary transplants utilizing unmodified PBPC from HLA-identical sibling donors reported to the European Group for Blood and Marrow Transplantation (EBMT) for 1994. 59 patients with a median age of 39 years received myeloablative therapy for acute myelogenous leukaemia (23 patients), acute lymphoblastic leukaemia (13), chronic myelogenous leukaemia (nine), lymphoma (seven), or other diagnoses (seven) mostly of advanced stages followed by transplantation of allogeneic PBPC. Three patients died soon after grafting, the others showed prompt haemopoietic recovery with median times to recover an absolute neutrophil count (ANC) above 0.5 and 1.0×10⁹/l of 15 (range 9–27) and 17 d (range 10–28) respectively. Time to platelet recovery above 20 or 50×10⁹/l was 16 (range 9–76) and 18 d (range 12–100) respectively. 27 patients (46%) developed no or mild acute graft-versus-host disease (GVHD). The incidence of moderate (grade II) disease was 27%; 24% of the patients developed severe acute GVHD (grades III or IV). 55% of patients who were alive 90 d after transplantation developed chronic GVHD, the probability to develop extensive chronic GVHD was 32% (95% confidence interval 22–42) with a median follow-up of 14 months. Overall and event-free survival (EFS) at 1 year were 54% (CI 48–60) and 50% (CI 43–57), respectively, the relapse incidence was 23% (CI 17–29). EFS was 67% (CI 55–79) in patients transplanted for acute leukaemias in first complete remission, chronic myelogenous leukaemia in first chronic phase, or severe aplastic anaemia. Transplantation of allogeneic PBPC resulted in prompt and durable engraftment. The incidence and severity of acute and chronic GVHD seemed comparable to that observed after allogeneic BMT. Overall and event-free survival in this cohort of patients, most of whom suffered from advanced leukaemia or lymphoma, is encouraging, suggesting that the high numbers of T lymphocytes and/or natural killer cells contained in a typical PBPC collection product exert a vigorous graft-versus-leukaemia effect. Further evaluation of allogeneic PBPCT is highly desirable.     

Isolation of mesenchymal stem cells from G-CSF-mobilized human peripheral blood using fibrin microbeads

Adult mesenchymal stem cells (MSC) that are able to differentiate into various mesenchymal cell types are typically isolated from bone marrow, but their significant presence in human peripheral blood (PB) is controversial. Fibrin microbeads (FMB) that bind matrix-dependent cells were used to isolate MSC from the mononuclear fraction of mobilized PB of adult healthy human donors treated with a granulocyte colony-stimulating factor. Isolation by plastic adherence resulted in a negligible number of MSC in all samples tested, whereas FMB-based isolation yielded spindle-shaped cell samples that could further expand on plastic or on FMB in eight out of the 11 samples. The yield of these cells at days 17-18 after the harvest was approximately 0.5% of the initial cell number. The isolated cells were grown on plastic and characterized by FACS analysis and immunohistochemistry for specific markers. Following culturing and first passage, the FMB-isolated cells stained positive for mesenchymal stromal cell markers CD90 and CD105, expressed vimentin and fibronectin and were negative for hematopoietic markers CD45 and CD34. These cells could differentiate into osteoblasts, adipocytes and chondrocytes. This study indicates that FMB may have special advantage in isolating MSC from sources such as mobilized PB, where the number of such cells is scarce.     

Modest stimulatory effect of recombinant human GM-CSF on colony growth from peripheral blood human megakaryocyte progenitor cells

Recombinant human granulocyte-macrophage colony-stimulating factor (rGM-CSF) has been previously demonstrated to stimulate colony formation from human myeloid, erythroid, and multipotential stem cells. In this investigation, we evaluated the effects of rGM-CSF on colony growth by human megakaryocyte progenitors (CFU-Meg). rGM-CSF was tested at concentrations of 0.1-100 U/ml in plasma clot cultures of adherent-depleted normal peripheral blood mononuclear cells. Control cultures were concurrently prepared containing either no stimulator or megakaryocyte colony-stimulating factor (Meg-CSF) partially purified from aplastic canine serum. rGM-CSF increased megakaryocyte colony numbers from a baseline of 4.3 +/- 1.4 (+/- SEM) in the unstimulated cultures to a maximum of 21.0 +/- 5.3 colonies at an rGM-CSF concentration of 1.0 U/ml. Corresponding megakaryocytic colony size increased from 4.4 to 8.3 cells/colony. Further increasing the rGM-CSF concentration resulted in decreasing megakaryocyte colony growth, reaching 6.8 +/- 2.9 colonies at 100 U/ml. The maximum number of megakaryocyte colonies stimulated by rGM-CSF was only 23.3% of that achieved in the control cultures containing optimal concentrations of serum-derived Meg-CSF protein (2.0 mg/ml). Megakaryocyte colonies stimulated by rGM-CSF consisted of predominantly low ploidy cells approximately equally distributed in 2N, 4N, and 8N ploidy classes. There was no increase in ploidy with any rGM-CSF concentration. These data indicate that rGM-CSF has modest activity in stimulating human megakaryocyte colony growth that is substantially less than that present in serum-derived Meg-CSF. rGM-CSF appears to primarily affect the early mitotic phase of megakaryocyte colony development with little influence on megakaryocyte endoreduplication.     

Isolation of large numbers of dispersed human pituitary adenoma cells obtained by aspiration

Since the extent of in vitro experiments with human pituitary adenoma cells is often limited by the small number of cells isolated from surgical specimens, ways to obtain more cells are of interest. In this study we made use of tumor tissue removed by aspiration through a suction tube during transsphenoidal surgery. Fifteen out of 28 adenomas could be dispersed without enzymatic treatment. The other 13 adenomas were mildly treated with Dispase. The large number of red blood cells present in the suction tube were removed by Ficoll-Isopaque density centrifugation. More than 90% of the adenoma cells were recovered from the interphase fraction. This material, in contrast with fragments obtained with a forceps, yielded 35.9 (+/-9.0) X 10(6) cells (mean +/- SE, n = 28). Usually less than 10% of these cells were mononuclear leucocytes. Pituitary hormones other than those hypersecreted in vivo were not found in the incubation media; only small amounts of LH were found in 5 out of 25 adenomas. A linear relationship was found between cell concentration and hormone secretion, both for PRL and GH. In vitro hormone secretion by the adenoma cells was in good agreement with in vivo dynamic tests. In longterm culture, GH and ACTH secretion by the adenoma cells declined, while PRL secretion was fairly constant. It is concluded that large numbers of dispersed pituitary adenoma cells can be obtained from the material removed by suction during transsphenoidal operation.(ABSTRACT TRUNCATED AT 250 WORDS)