Interleukin-5, interleukin-3, and granulocyte-macrophage colony-stimulating factor cross-compete for binding to cell surface receptors on human eosinophils.

Human interleukin (IL)-5 receptors were characterized by means of binding studies using bioactive 125I-labeled IL-5. Of purified primary myeloid cells, eosinophils and basophils but not neutrophils or monocytes expressed surface receptors for IL-5. Binding studies showed that eosinophils expressed a single class of high affinity receptors (Ka = 1.2 x 10(10) M-1) with the number of receptors being small (less than 1000 receptors/cell) and varying between individuals. Among several cell lines examined only HL-60 cells showed detectable IL-5 receptors which were small in numbers (200 receptors/cell) and also bound 125I-IL-5 with high affinity. The binding of IL-5 was rapid at 37 degrees C while requiring several hours to reach equilibrium at 4 degrees C. Specificity studies revealed that the two other human eosinophilopoietic cytokines IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) inhibited the binding of 125I-IL-5 to eosinophils. No competition was observed by other eosinophil activating or nonactivating cytokines. The inhibition of 125I-IL-5 binding by IL-3 and GM-CSF was partial up to a concentration of competitor of 10(-7) M with GM-CSF consistently being the stronger competitor. Converse experiments using IL-5 as a competitor revealed that this cytokine inhibited the binding of 125I-IL-3 and of 125I-GM-CSF in some but not all the individuals tested, perhaps reflecting eosinophil heterogeneity in vivo. Cross-linking experiments on HL-60 cells demonstrated two IL-5-containing complexes of Mr 150,000 and Mr 80,000 both of which were inhibited by GM-CSF. The competition between IL-5, IL-3, and GM-CSF on the surface of mature eosinophils may represent a unifying mechanism that may help explain the common biological effects of these three eosinophilopoietic cytokines on eosinophil function. This unique pattern of competition may also be beneficial to the host by preventing excessive eosinophil stimulation.     

Suppression of the development of uterine adenomyosis by danazol treatment in mice.

Inhibitory effects of danazol, an isoxazol derivative of synthetic steroid 17 alpha-ethinyl-testosterone, on the development of uterine adenomyosis, a pathological disorder of endometrial tissue defined as the presence of endometrial glands and stroma in the myometrium, were investigated in mice of SHN strain. Mice treated with 0.5 microgram danazol for 5 weeks during 4-9 weeks of age and killed at 21 weeks of age showed significantly lower incidence of the spontaneous development of adenomyosis than the age-matched intact control mice. The inhibitory effects of danazol were also evident in mice bearing pituitary isografts which were effective in inducing an early and a high incidence of adenomyosis. Furthermore, the treatment with danazol resulted in the decrease of serum levels of luteinizing hormone (LH) and prolactin (PRL) associated with hypofunction of ovaries and persistent diestrus. These results support the usefulness of danazol for the clinical treatment of gynecological disorders except for hypofunction of ovaries.     

Purification of monomeric agmatine iminohydrolase from soybean

Agmatine iminohydrolase (EC 3.5.3.12) was purified to homogeneity from the cytosol of soybean (Glycine max) axes by chromatographic separations on Sephadex G-25, Bio-rex 70, and agmatine-affinity columns. The enzyme was homogeneous by the criteria of analytical gel electrophoresis. Molecular weights estimated by Sephadex G-100 gel and sodium dodecyl sulfate polyacrylamide gel electrophoresis were 70,000, indicating that the soybean axes enzyme is a monomer, in contrast to the dimeric enzymes from corn and rice. The isoelectric point determined by gel electrofocusing was 7.5, higher than that of the corn enzyme (4.7). The optimal pH and temperature for activity were 6.5 and 50 degrees C, respectively. The enzyme has high specificity for agmatine, and the Km for agmatine was 2.5 x 10(-3) molar. The enzyme was sensitive to Cu2+ and also was inhibited by p-hydroxymercuribenzoate.     

Hybrid cytokines as hematopoietic growth factors.

A large body of in vitro and in vivo data suggests that combinations of cytokines provide the most effective mechanism for stimulating multilineage acceleration of hematopoiesis. Creation of a granulocyte-macrophage colony-stimulating factor (GM-CSF)/interleukin 3 (IL-3) fusion protein has yielded a single therapeutic which has enhanced biological activity in comparison to the individual cytokines from which it is composed. In vivo studies with this fusion protein (PIXY321) suggest that it may provide a means to accelerate both neutrophil and platelet recovery in clinical settings in which hematopoiesis is suppressed. The biology of PIXY321 and the potential for other fusion proteins is discussed.     

Identification of new urinary metabolites of trimeprazine in rats by gas chromatography—mass spectrometry

The metabolites of trimeprazine were identified in urine of rats by gas chromatography—mass spectrometry. After the oral administration of trimeprazine, the urinary metabolites were extracted with diethyl ether before or after hydrolysis with β-glucuronidase. The identified metabolites were N-demethyltrimeprazine, 3-hydroxytrimeprazine, N-demethyl-3-hydroxytrimeprazine and trimeprazine sulphoxide.     

Prevention of Dahl salt-induced hypertension by chronic dietary tryptophan

Four-week-old inbred Dahl salt-sensitive (DS/JR) and Dahl salt-resistant (DR/JR) rats were placed on an 8% salt diet with or without a supplemental 2.5% tryptophan (Trp). Blood pressures were monitored for the next 5 weeks. Urine volumes and ion concentrations were measured during the 6th week. Blood pressures of DS/JR rats on control diets elevated rapidly and markedly, whereas pressures of DS/JR rats on the Trp-supplemented diet were not significantly elevated over those of DR/JR rats. Pressures of DR/JR rats were unaffected by Trp supplementation. Urinary sodium was significantly greater in DR/JR rats compared with DS/JR rats and was unaffected by Trp supplementation. This suggests that the antihypertensive effect of Trp was not at the level of the kidney. We conclude that dietary Trp blocks the development of hypertension in DS/JR rats maintained on a high salt diet.     

Light microscopic localization of labile calcium in hypertrophied chondrocytes of long bone with alizarin red S.

A method which localizes labile 5% ethylene glycol-bis-(beta-amino-ethyl ether)N-N'-tetraacetic acid-removable calcium in spherules within hypertrophied chondrocytes and in pericellular matrix using alizarin red S (ARS) is described. Fresh blocks of epiphyseal cartilage approximately 1 mm thick were immersed into 0.5-2% ARS solution containing 7% mounted on glass slides in 7% sucrose or in glycerol-gelatin. The stained tissue blocks were also dehydrated in acetone, cleared in xylene and mounted in Preservaslide. The ARS precipitated ionic calcium as red Ca-ARS salt which was birefringent in polarizing microscope, stable in water at pH 4-9 and in nonpolar organic solvent but soluble in polar solvents, especially in dimethyl sulfoxide. In contrast, ARS-stained insoluble calcium phosphate was stable even in dimethyl sulfoxide. Calcium in the hypertrophied chondrocytes, therefore, was thought to be present in a readily ionizable state instead of as insoluble calcium phosphate. Since addition of 7% sucrose retained as well as improved ARS localization of cellular calcium, the calcium was believed to be present in an osmotically sensitive, membrane-bound cytoplasmic compartment. The ARS-positive labile calcium in spherules which develop in the hypertrophied chondrocytes as well as in the pericellular matrix at the zone of provisional calcification suggested a preparatory stage in the process of cartilage calcification.     

IL‐23 plays a significant role in the augmentation of particulate matter‐mediated allergic airway inflammation

It has been recently that particulate matter (PM) exposure increases the risk and exacerbation of allergic asthma. However, the underlying mechanisms and factors associated with increased allergic responses remain elusive. We evaluated IL‐23 and IL‐23R (receptor) expression, as well as changes in the asthmatic phenotype in mice administered PM and a low dose of house dust mite (HDM). Next, changes in the phenotype and immune responses were evaluated after intranasal administration of anti‐IL‐23 antibody during co‐exposure to PM and low‐dose HDM. We also performed in vitro experiments to investigate the effect of IL‐23. IL‐23 expression was significantly increased in Epcam+CD45− and CD11c+ cells, while that of IL‐23R was increased in Epcam+CD45− cells only in mice administered PM and low‐dose HDM. Administration of anti‐IL‐23 antibody led to decreased airway hyperresponsiveness, eosinophils, and activation of dendritic cells, reduced populations of Th2 Th17, ILC2, the level of IL‐33 and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF). Inhibition of IL‐23 in PM and low‐dose HDM stimulated airway epithelial cell line resulted in decreased IL‐33, GM‐CSF and affected ILC2 and the activation of BMDCs. PM augmented the phenotypes and immunologic responses of asthma even at low doses of HDM. Interestingly, IL‐23 affected immunological changes in airway epithelial cells.