Abnormal function of the bone marrow microenvironment in chronic myelogenous leukemia: role of malignant stromal macrophages

The bone marrow microenvironment supports and regulates the proliferation and differentiation of hematopoietic cells. Dysregulated hematopoiesis in chronic myelogenous leukemia (CML) is caused, at least in part, by abnormalities in CML hematopoietic progenitors leading to altered interactions with the marrow microenvironment. The role of the microenvironment itself in CML has not been well characterized. We examined the capacity of CML stroma to support the growth of long-term culture-initiating cells (LTC-IC) obtained from normal and CML marrow. The growth of normal LTC-IC on CML stroma was significantly reduced compared with normal stroma. This did not appear to be related to abnormal production of soluble factors by CML stroma because normal LTC- IC grew equally well in Transwells above CML stroma as in Transwells above normal stroma. In addition, CML and normal stromal supernatants contained similar quantities of both growth-stimulatory (granulocyte colony-stimulating factor (CSF), interleukin-6, stem cell factor, granulocyte-macrophage CSF, and interleukin-1 beta) and growth- inhibitory cytokines (transforming growth factor-beta, macrophage inflammatory protein-1 alpha, and tumor necrosis factor-alpha). The relative proportion of different cell types in CML and normal stroma was similar. However, polymerase chain reaction and fluorescence in situ hybridization studies showed the presence of bcr-abl-positivo cells in CML stroma, which were CD14+ stromal macrophages. To assess the effect of these malignant macrophages on stromal function, CML and normal stromal cells were separated by fluorescence-activated cell sorting into stromal mesenchymal cell (CD14-) and macrophage (CD14+) populations. CML and normal CD14- cells supported the growth of normal LTC-IC equally well. However, the addition of CML macrophages to normal or CML CD14- mesenchymal cells resulted in impaired progenitor support. This finding indicates that the abnormal function of CML bone marrow stroma is related to the presence of malignant macrophages. In contrast to normal LTC-IC, the growth of CML LTC-IC on allogeneic CML stromal layers was not impaired and was significantly better than that of normal LTC-IC cocultured with the same CML stromal layers. These studies demonstrate that, in addition to abnormalities in CML progenitors themselves, abnormalities in the CML marrow microenvironment related to the presence of malignant stromal macrophages may contribute to the selective expansion of leukemic progenitors and suppression of normal hematopoiesis in CML.     

Kinetic evaluation of the pool sizes and proliferative response of neutrophils in bacterially challenged aging mice

Clinical observations during infection suggest that in aged patients, the kinetic or proliferative responses of neutrophils to infection may be deranged. To test this hypothesis, the neutrophil responses of 6- month-old and 30-month-old mice were compared. After intrapulmonary injection of Escherichia coli, young mice exhibited neutrophilia and diminution of the neutrophil storage pool (NSP) by a mean of 6.4 x 10(6) neutrophils/two femurs. This was accompanied by an increase in the pool of CFU-GM from a control value of 1.1 x 10(5) cells/two femurs (range 0.7 to 1.4) to 1.5 x 10(5) (1.1 to 1.9) (P less than .05) and the thymidine suicide (relative proliferative rate) of CFU-GM rose from 27% (19 to 42) to 51% (31 to 61) (P less than .05). Furthermore, the CFU-GM of infected young mice displayed enhanced differentiation to the neutrophil series. In contrast, old mice exhibited a greater mean diminution of the NSP: 12.8 x 10(6) neutrophils. Also, old mice experienced a reduction in CFU-GM from 2.3 x 10(5) (1.0 to 3.9) (controls) to 1.3 x 10(5) (1.2 to 1.5)/two femurs (P less than .05), a reduction in the proliferation of CFU-GM and reduced differentiation of CFU-GM to neutrophils. These experiments establish that the neutrophil response of infected old mice is disordered, with exaggerated depletion of the NSP and lack of stimulus-driven granulocytopoiesis as reflected by a paradoxical reduction in the number and proliferative rate of precursors. This defect may be compounded by decreased differentiation of precursors to neutrophils.     

Efficacy and safety of ticlopidine monotherapy versus ticlopidine and aspirin after coronary artery stenting: follow-up results of a randomized study

A combined antiplatelet treatment with ticlopidine and aspirin has been accepted as standard pharmacological regimen after coronary artery stenting. No data of a randomized trial are available on ticlopidine monotherapy. This prospective, randomized monocenter trial investigates the role of ticlopidine monotherapy versus combined antiplatelet therapy with ticlopidine and aspirin in unselected patients undergoing coronary artery stenting. After successful placement of 378 coronary artery stents, two hundred and forty-three consecutive patients were randomly assigned to receive antiplatelet therapy with 2 x 250 mg ticlopidine (121 patients) or a combination of 2 x 250 mg ticlopidine plus 100 mg aspirin (122 patients) daily. The primary endpoint included the absence of death, cardiac events and vascular access-site complications during the in-hospital phase. Angiographic and clinical assessment was repeated at the 3-month follow-up exam. Two hundred and thirty-seven patients (97.5%) were free from cardiac and non-cardiac events. Stent thromboses were seen in 2 patients of the combined treatment group, while none were observed in the monotherapy group. No statistically significant differences were found between the 2 groups regarding the primary endpoint. Angiography performed in 210 patients (86.4%) at follow-up revealed a restenosis rate of 29.4% in the combined treatment group and 27.8% in the monotherapy group. Monotherapy with ticlopidine is as safe and effective as a combined regimen of ticlopidine plus aspirin after coronary artery stenting in an unselected patient population. These results need to be confirmed in a larger multicenter trial.     

Gastric mucosal blood flow and pepsin secretion in dogs--stimulation by 13-nle-motilin.

In response to graded doses of intravenous 13-norleucine-motilin (13-nle-motilin)--a synthetic analogue of motilin and biologically equivalent to the natural polypeptide-, gastric mucosal blood flow (GMBF) in canine vagally denervated fundic pouches was studied using the aminopyrine clearance technique. As 13-nle-motilin did not exert any detectable effect on gastric secretion of hydrogen ions, intraluminal instillation of 160 mM HCl was used to provide a pH gradient allowing aminopyrine to move into the pouch lumen. With increasing doses of 13-nle-motilin, GMBF increased to 148% of control values; pepsin secretion - due to augmented pepsin concentration - rose concomitantly. Enhanced pepsin secretion was not accompanied by an increase in cyclic 3',5'-adenosine monophosphate secretion.     

Role of gonadotropins in malignant progression of sex cord stromal tumors produced by sequential auto- and isogenic transplantation of ovarian tissue in ovariectomized rats

Purpose: In this study the effect of continuous stimulation of gonadotropins on sex cord stromal tumors in the rat was examined. Methods: Sex cord stromal tumors were induced by transplantation of ovaries under the splenic capsule of ovariectomized rats. Beginning 180 days after transplantation, these tumors were taken out and cut into several pieces, which were then retransplanted (by isotransplantation) under the splenic capsule of 80 either intact or ovariectomized rats. Results: Most of the tumor grafts grew up to a median size of 0.7 cm in ovariectomized rats. However, some of the tumors recovered from recipient rats that were retransplanted with donor tumors differed significantly from the others. Characterized by a high mitotic rate, nuclear atypia, size (up to 3.8 cm) as well as growth in intact animals, these tumors were defined as malignant. They could be kept in culture and always led to the development of metastases after retransplantation into other rats. Conclusion: Benign sex cord stromal tumors can show malignant growth after transplantation. This study for the first time demonstrates that gonadotropins are involved in the induction of ovarian malignancies. Received: 15 December 2000 / Accepted: 15 February 2001     

Über das Bronchuskarzinoid

Zusammenfassung Mittels der modifizierten Imprägnationsmethode nachBodian gelang es, argyrophile Körnchen in den epithelialen Zellen zweier Bronchuskarzinoide darzustellen, in einem der Fälle auch in hämatogenen Fernmetastasen. Man kann in diesem Befund eine weitere Analogie zwischen den Bronchus- und Darmkarzinoiden erblicken, denen die Bronchuskarzinoide auch sonst in Struktur (s. Abb. 3a und b) und klinischem Verhalten weitgehend entsprechen. Die Bezeichnung Karzinoid ist also treffender als die Bezeichnung Bronchialadenom, eventuell unter Beifügung vom karzinoiden Typ. Anhangseeise wird eine Übersicht über die in der Literatur mitgeteilten Fälle von Bronchuskarzinoiden gegeben.Mit 5 Textabbildungen     

Non-linear adaptive controllers for an over-actuated pneumatic MR-compatible stepper

Pneumatics is one of the few actuation principles that can be used in an MR environment, since it can produce high forces without affecting imaging quality. However, pneumatic control is challenging, due to the air high compliance and cylinders non-linearities. Furthermore, the system’s properties may change for each subject. Here, we present novel control strategies that adapt to the subject’s individual anatomy and needs while performing accurate periodic gait-like movements with an MRI compatible pneumatically driven robot. In subject-passive mode, an iterative learning controller (ILC) was implemented to reduce the system’s periodic disturbances. To allow the subjects to intend the task by themselves, a zero-force controller minimized the interaction forces between subject and robot. To assist patients who may be too weak, an assist-as-needed controller that adapts the assistance based on online measurement of the subject’s performance was designed. The controllers were experimentally tested. The ILC successfully learned to reduce the variability and tracking errors. The zero-force controller allowed subjects to step in a transparent environment. The assist-as-needed controller adapted the assistance based on individual needs, while still challenged the subjects to perform the task. The presented controllers can provide accurate pneumatic control in MR environments to allow assessments of brain activation.