National Jewish Health

About: National Jewish Health is a healthcare organization based out in Denver, Colorado, United States. It is known for research contribution in the topics: T cell & Asthma. The organization has 883 authors who have published 833 publications receiving 79201 citations. The organization is also known as: National Jewish Medical and Research Center.

Bronchoarterial ratio on thin section CT: comparison between high altitude and sea level.

Abstract: PURPOSE Our goal was to measure normal bronchial to accompanying pulmonary arterial diameter ratios and normal bronchial wall thickness on thin section CT at high altitude and at sea level. METHOD Seventeen normal, healthy, nonsmoking subjects living at 1,600 m altitude and 16 living at sea level underwent thin section CT (1.5 to 2.0 mm collimation). All images were photographed at window levels of -450 and -700 HU and window width of 1,500-1,600 HU. Internal diameters of the segmental and subsegmental bronchi were measured and compared with the diameter of the adjacent pulmonary artery. Bronchial wall thickness of each bronchus was measured. Only bronchi and arteries seen in cross section and within 1 mm from each other were included in the analysis. RESULTS Four hundred sixty-seven bronchi (215 at high altitude, 252 at sea level) were assessed. At window level of -450 HU, the bronchoarterial ratio was 0.76 +/- 0.14 (mean +/- SD) at altitude and 0.62 +/- 0.13 at sea level (p < 0.001). Bronchial wall thickness measured 0.92 +/- 0.09 mm (mean +/- SD) at altitude and 1.12 +/- 0.19 mm at sea level (p < 0.001). At window level of -700 HU, there was an artifactual decrease in the bronchoarterial diameter ratios and an increase in bronchial wall thickness. CONCLUSION Bronchoarterial ratio increases and bronchial wall thickness decreases with altitude. These findings are presumably related to hypoxic bronchodilatation and vasoconstriction.

Factor B of the alternative complement pathway regulates development of airway hyperresponsiveness and inflammation

Abstract: Exposure to inhaled allergens leads to increases in airway hyperresponsiveness (AHR) and inflammation, associated with increased levels of biologically active fragments derived from the complement C3 and C5 family of proteins. Further, complement activation during allergen challenge in sensitized animals is necessary for the development of AHR and airway inflammation. To define the complement pathway involved, we studied mice deficient in complement factor 4 (C4−/−), a critical component of the classical pathway, or factor B (fB−/−), an essential protein in the alternative complement pathway. WT, C4−/−, and fB−/− mice were sensitized to ovalbumin and subsequently exposed to nebulized ovalbumin (1% in saline) on 3 consecutive days. After allergen sensitization and challenge, fB−/− mice demonstrated significantly lower airway responsiveness to methacholine and less airway inflammation. In contrast, C4−/− mice showed no reduction in AHR and airway inflammation compared with WT mice. Tissue inflammation, goblet cell hyperplasia, and IL-4, IL-5, and IL-13 levels in BAL fluid were significantly reduced in fB−/− mice compared with C4−/− and WT mice. The development of AHR and airway inflammation in sensitized fB−/− mice could be restored after intranasal administration of purified factor B before the airway challenge. In addition, administration of a neutralizing anti-factor B mAb to sensitized mice before airway challenge reduced the development of AHR and airway inflammation. These results demonstrate that in sensitized hosts complement activation through the alternative pathway after allergen exposure is critical to the development of AHR and airway inflammation.

gp120 ligation of CD4 induces p56lck activation and TCR desensitization independent of TCR tyrosine phosphorylation.

Abstract: HIV gp120 binding to CD4 suppresses TCR function The molecular mechanism of this anergizing effect is incompletely understood Studies reported here reveal that CD4 ligation initiates p56lck activation and renders human peripheral T cells and HPB-ALL cells hyporesponsive to Ag receptor stimulation, as indicated by the failure of TCR binding ligands to induce either protein tyrosine phosphorylation or elevation of intracellular-free calcium concentration To approach the possibility that p56lck-mediated tyrosine phosphorylation of specific sites within TCR zeta-chain might be involved in the gp120-induced TCR signaling defect, we tested the kinase's ability to phosphorylate various zeta peptides Kinetics analyses indicate that peptides derived from the in vitro autophosphorylation site of p56lck Y394 and two sites within zeta, Y84, and Y152, are equally effective substrates for p56lck, whereas p56fyn prefers a substrate peptide derived from a different site within zeta, Y142 Although these data are consistent with the possibility that gp120-mediated signal disruption of TCR could be due to p56lck phosphorylation of Y84 and Y152 residues within zeta, further experiments revealed that gp120 does not induce detectable zeta tyrosine phosphorylation under conditions in which it disrupts TCR signaling These data indicate that gp120 can induce uncoupling of TCR from the earliest events in signal transduction and that this effect can be mediated by a mechanism other than tyrosine phosphorylation of TCR zeta-chain

Ribosome-inactivating proteins in plant biology.

Abstract: Ribosome-inactivating proteins (RIPs) are a group of cytotoxic Af-glycosidases that specifically cleave nucleo tide N-C glycosidic bonds. RIPs have been classified into three types: type I is composed of a single polypeptide chain, whereas type II is a heterodimer consisting of an A chain, functionally equivalent to a type I, which is attached to a sugar-binding B chain. Type III is a single chain containing an extended carboxyl-terminal domain with unknown function. Although RIPs were first identified more than 100 years ago, their biological function(s) still remains open to speculation. Besides their known activity of depurinating ribosomes at the