Ex vivo culture of peripheral blood CD34+ cells: effects of hematopoietic growth factors on production of neutrophilic precursors

A major potential application for ex vivo culture of hematopoietic progenitor cells is the treatment of cytopenia following high-dose chemotherapy and hematopoietic transplantation. We have previously postulated that infusion of a sufficient number of neutrophil postprogenitor cells generated by ex vivo culture of CD34+ cells may be able to abrogate neutropenia. In this article, we describe further development of an efficient stromal-free, cytokine-dependent, static culture system for generation of these cells. Our previous studies indicated that maximal production of nucleated cells and myeloid progenitor cells from PB CD34+ cells occurred with multiple hematopoietic growth factor (HGF), notably the 6-HGF combination of interleukin (IL)-1, IL-3, IL-6, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage-CSF (GM-CSF), and stem cell factor (SCF). In the present study, we determine the contribution of each of these 6 HGF in generation of neutrophilic precursors. SCF, G-CSF, and IL-3 were found to be the most important HGF for production of neutrophilic cells. The 4-HGF combination of IL-3, IL-6, G-CSF, and SCF was optimized by performing dose-response experiments and shown to be as potent as 6 HGF for production of nascent CFU-GM and neutrophilic precursors.     

Cognitive difficulty of a peripherally presented visual task affects head movements during gaze displacement

Characterization of flow properties of an artificial ventricle may aid development of designs to minimize thrombosis. Techniques for determining two such flow properties, viz. ventricular clearance rate and ejection fraction, are compared and validated here for polyurethane and silicone rubber ventricles operated in a mock circulatory loop at various stroke volumes and pulse rates. Ventricular clearance rats were measured both by clinical radionuclide tracer techniques and by an optical tracer method. Ejection fractions were measured by radionuclide imaging and validated by direct measurements of flow rate and ventricular volume. Results from the two methods for ventricular clearance are in close agreement. The optical tracer method is superior in spatial resolution, convenience and economy, but the radionuclide tracer method for ejection fraction gives excellent agreement with the absolute measurements.     

Vaccination for experimental gliomas using GM-CSF-transduced glioma cells

Within the pituitary, folliculostellate (FS) cells are considered to regulate the intercellular communication between endocrine cells by paracrine mechanisms. One of the possible paracrine factors involved, could be interleukin-6 (IL-6) which is produced by these cells. Since IL-6 has been shown to be a growth factor of pituitary cells, we have determined whether IL-6 can also influence FS cell proliferation. To test this, a FS cell-like mouse pituitary cell line (TtT/GF cells) was used that exhibits most characteristics of normal FS cells. Under serum-free conditions the proliferation of TtT/GF cells is critically dependent on the initial seeding density: cells seeded at low density do not grow at all whereas cells seeded at high density proliferate with maximal doubling times of 34 hrs. Mouse IL-6 (mIL-6) stimulated only low density cell cultures in a dose and time dependent manner. For cells seeded at high density, exogenously added IL-6 may have failed to stimulate growth because of endogenously produced mIL-6. Conditioned medium from TtT/GF cells, in which mIL-6 concentrations up to 1017 pg/ml were measured, stimulated the proliferation of TtT/GF cells, indicating an autocrine growth stimulatory mechanism. A neutralizing mIL-6 antibody partially suppressed the growth of TtT/GF cells seeded at high density and partially reduced the growth stimulatory activity of TtT/GF conditioned medium. Thus, IL-6 is one but not the only factor that is involved in the autocrine growth stimulatory loop. The relevance of this mechanism for normal FS cells and its physiological consequence needs to be elucidated.     

Efficiency of energy-engineering schemes for processing petroleum

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 1, pp. 5–8, January, 1990.     

Axis II psychopathology as a function of Axis I disorders in childhood and adolescence

OBJECTIVE: To examine the occurrence of elevated personality disorder (PD) dimensional scores in a community sample of young adults as a function of the occurrence of Axis I disorders through age 18 years. METHOD: 299 individuals who had been interviewed regarding Axis I disorders twice while in adolescence (first when 14 through 18 years of age) were carefully assessed regarding Axis I and II psychopathology at age 24. RESULTS: The prevalence of PD diagnoses was relatively low (3.8% in participants with a history of Axis I versus 1.7% in participants with no Axis I history). The occurrence of all four Axis I diagnostic categories (major depression, anxiety disorders, disruptive behavior disorders, substance use disorders) in childhood and adolescence was associated with elevated PD dimensional scores. The likelihood of elevated PD dimensional scores increased as a function of the number of Axis I disorders. Elevated PD scores were significantly associated with a negative course of major depression. CONCLUSIONS: Although the rates of PDs were low, the findings suggest a substantial degree of association between early-onset Axis I disorders and Axis II psychopathology in young adulthood. More research is needed to develop assessment and treatment recommendations addressing the early manifestations of PDs.     

Simulation of the current switching by a metal-insulator transition

A one-dimensional simulation of the nonlinear diffusion of magnetic field through a shield made of the solid solution (V_1?X Cr_X)₂O₃ is carried out. Also simulated is the current switching from this shield to load when the former undergoes a metal-insulator transition. Pronounced steepening of a current pulse edge in the load circuit is demonstrated to be possible.