Eradication of Tuberculosis in Children

Human tracheobronchial clearance was studied with a test aerosol of monodisperse particles (approximately 7μ) of fluorinated ethylene propylene (Teflon 120) tagged with radioactive fluorine (¹⁸F), a positron emitter with a half-life of 110 minutes. Eight subjects were exposed twice to the test aerosol. The clearance differed appreciably between the individuals but the two determinations in the same individual are highly similar. The test aerosol employed should be suitable for intraindividual studies of tracheobronchial clearance in man and consequently of value for investigating the acute effect of different substances on tracheobronchial clearance.     

Autonomic and psychological responses to an acute psychological stressor and relaxation: The influence of hypnotizability and absorption

This study examined the influence of hypnotizability and absorption on psychological and autonomic responses to an experimental stressor and a relaxation procedure of 13 high and 13 low hypnotizable subjects. Heart-rate variability was the measure of autonomic reactivity. Absorption was found to be the only significant predictor of autonomic reactivity in both experimental conditions. Expectation and previous relaxation training, but not absorption or hypnotizability, predicted perceived relaxation in the relaxation condition. The results suggest that in a nonhypnotic context the influence of hypnotizability on responses to experimental conditions may be less prominent than the influence of absorption. Absorption may be associated with greater awareness of internal physical and psychological processes, and the results support previous clinical findings of positive correlations between absorption, subjective perception of autonomic arousal, and somatic symptom reporting.     

Adult bone marrow-derived stem cells use R-cadherin to target sites of neovascularization in the developing retina.

Adult bone marrow contains a population of hematopoietic stem cells (HSCs) that can give rise to cells capable of targeting sites of neovascularization in the peripheral or retinal vasculature. However, relatively little is known about the mechanism of targeting of these cells to sites of neovascularization. We have analyzed subpopulations of HSCs for the expression of a variety of cell surface adhesion molecules and found that R-cadherin, a calcium-dependent cell-cell adhesion molecule important for normal retinal endothelial cell guidance, was preferentially expressed by functionally targeting HSCs. Preincubation of HSCs with function-blocking anti-R-cadherin antibodies or novel R-cadherin-specific peptide antagonists effectively prevented targeting of bone marrow-derived cells to the developing retinal vasculature in vivo. Whereas control-injected HSCs targeted to all 3 normal developing retinal vascular layers, blocking R-cadherin-mediated adhesion resulted in mistargeting of the HSCs to the normally avascular outer retina. Our results suggest that vascular targeting of bone marrow-derived HSCs is dependent on mechanisms similar to those used by endogenous retinal vascular endothelial cells. Thus, R-cadherin antagonists may be useful in the treatment of neovascular diseases in which circulating HSCs contribute to abnormal angiogenesis.