Inhibition of antigen-induced airway and cutaneous responses by heparin: a pharmacodynamic study

We have previously shown that heparin attenuates the acute bronchoconstrictor response and immediate cutaneous reaction (ICR) to antigen in allergic sheep. In the present investigation, we studied the pharmacodynamics of the antiallergic action of heparin. Specific lung resistance (sRL) was measured in eight sheep, allergic to Ascaris suum antigen, before and 5 min after inhalation challenge with the antigen. On different experiment days, antigen challenge was repeated after pretreatment with 1) aerosol heparin (1,000 U/kg) administered < or = 20 min, 6 h, 12 h, and 24 h and 2) intravenous heparin (1,000 U/kg) administered < or = 20 min, 1 h, 6 h, and 12 h before antigen challenge. sRL increased by 374 +/- 116% (SE) above baseline with antigen alone. Both aerosol and intravenous heparin attenuated the antigen effects on sRL in a time-dependent fashion. Prolonging the lag time between pretreatment and antigen challenge decreased the inhibitory effect of aerosol heparin; delta sRL was 31 +/- 29, 99 +/- 38, 142 +/- 40, and 306 +/- 60% for < or = 20-min, 6-h, 12-h, and 24-h pretreatment protocols, respectively. In contrast, prolonging the lag time increased the inhibitory effect of intravenous heparin: delta sRL was 246 +/- 64, 66 +/- 26, and 76 +/- 32% for < or = 20 min, 1 h, and 6 h, respectively. In seven additional sheep pretreatment with intravenous heparin (1,000 U/kg) attenuated the ICR also in a time-dependent manner; the inhibitory effect of heparin on ICR to antigen was enhanced 60% by increasing the heparin pretreatment interval from 20 to 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Parametric dependence of stochastic frequency variations in thegain switching of a single-mode laser diode

The authors have studied the fluctuations in the range of frequency excursions of the optical field from a single-mode laser diode that has been switched-on by a stepwise increase, in the current from a bias level which is below threshold. Both the maximum and the minimum frequencies reached in the transient for each gain-switching event are linear functions of the turn-on time. The statistics of the range of frequency variation for different turn-on events are then easily obtained from the statistics of the turn-on time. The slopes of these functions depend linearly on the injection current of the single-mode laser diode. In addition, they depend not only on the saturation intensity of the single-mode laser diode, but also on the particular form of gain saturation. As a consequence, experimental measurements could be used, in principle, to determine which model of gain saturation best describes the operation of a given single-mode laser diode     

Synthesis and properties of poly(phenylene sulfide)s containing carbonyl and sulfonyl groups

With a view to study and compare the properties of poly(phenyienc sulfide)s containing carbonyl and sulfonyl backbone units, 1,4-bis(phenylthio)-benzene, and bis(4-phenylthio)diphenyl sulfone, were prepared and subjected to Fricdel-Crafts type polycondensation with various aromatic diacid chlorides. The resulting polymers had inherent viscosities in the range 0.101—0.141 dl/g. These polymers were not soluble in common organic solvents and exhibited good thermal stabilities.     

A 4-GHz 130-nm address generation unit with 32-bit sparse-tree adder core

This paper describes a 32-bit address generation unit designed for 4-GHz operation in 1.2-V 130-nm technology. The AGU utilizes a 152-ps sparse-tree adder core to achieve 20% delay reduction, 80% lower interconnect complexity, and a low (1%) active energy leakage component. The dual-V/sub T/ semidynamic implementation of the adder core provides the performance of a dynamic CMOS design with an average energy profile similar to static CMOS, enabling 71% savings in average energy with a good sub-130-nm scaling trend.     

Transfer of human adenine deaminase gene into murine hematopoietic stem cells: sequential study of spleen colony-forming units from bone marrow of living mice and the requirement of the microenvironment

PURPOSE: To explore relationships between pregnant women's childhood experiences with discipline and 1) prenatal plans for disciplining own child and 2) later maternal-infant interactions DESIGN: Prospective correlation study. SETTING: Prenatal clinics and home visits PARTICIPANTS: Low-income pregnant women (N = 205) with a mean educational level of 12 years MAIN OUTCOME MEASURES: Adapted Ways of Handling Irritating Behaviors (Mother and You) Scales, NCAST Teaching Scale, Home Observation for Measurement of the Environment Scale RESULTS: Correlations between childhood experiences with discipline and 1) plans for later discipline strategies with own child and 2) infant components of maternal-infant interactions, including clarity of cues and responsiveness to the mother CONCLUSIONS: Prenatal assessment for childhood experiences with discipline may uncover factors associated with a break in the trajectory for optimal maternal-child interactions described by Barnard's theoretical framework.     

Heme oxygenase induction with attenuation of experimentally induced corneal inflammation

Heme oxygenase (HO), by catabolizing heme to bile pigments, down-regulates cellular levels of heme and hemeproteins; certain of the latter, i.e. cytochrome P450s, generate pro-inflammatory products from endogenous substrates. Two HO isozymes, the products of distinct genes, have been described; HO-1 is the inducible one, whereas HO-2 is believed to be constitutively expressed. We studied the inducing effects of several metal compounds [CoCl2, SnCl2, ZnCl2, heme, and cobalt protoporphyrin (CoPP)] on HO-1 mRNA content and enzyme activity in cultures of rabbit corneal epithelial (RCE) cells; these metal compounds are known to induce HO in other tissues. Additionally, we studied HO-1 expression in an experimental model of ocular inflammation produced in rabbit corneas by extended contact lens wear, and the relation of HO expression to the induced inflammatory process. SnCl2 added to RCE cells in vitro produced marked time- and concentration-dependent increases in HO-1 mRNA and HO-1 enzyme activity; CoCl2, ZnCl2, and CoPP were inducers of HO as well, though to a lesser degree than SnCl2. Corneas treated for 6 days with contact lenses impregnated with SnCl2 displayed substantially less corneal inflammation, swelling, and new vessel invasion than did controls; attenuation of ocular inflammation was paralleled by SnCl2-induced increases in HO mRNA and HO activity in corneal epithelial cells from treated eyes. It is suggested that amelioration of the inflammatory response produced by extended contact lens wear is due, in part, to the induction of high levels of HO-1 activity by SnCl2, which results in diminished production of pro-inflammatory mediators generated through heme-dependent metabolic processes. Regulation of HO activity in this manner may have clinical applications.     

Characterization of Heterogeneous Soils Using Surface Waves: Homogenization and Numerical Modeling

Seismic surface waves are well-adapted to study the elastic parameters, and hence the mechanical properties, of soils. The aim herein is to evaluate whether Rayleigh waves in heterogeneous soils may be used to estimate average elastic parameters and to determine how these parameters are influenced by heterogeneities. The heterogeneous medium, underlain by a homogeneous half-space, is considered as a homogeneous matrix with one or several types of randomly distributed inclusions (with a normal distribution) in the matrix. Seismic waves generated by surface loads and propagating in this medium were calculated using the finite element method (FEM) and then compared with single- and multiple-scattering homogenization methods. For the FEM calculation, special care was taken to reduce numerical dispersion through the use of elements smaller than 1/20 of the dominant wavelength. The group and phase velocity dispersion curves were measured and inverted in order to obtain the effective shear wave velocity of the heterogeneous medium. The results show a clear dependence of the wave velocity with respect to the nature, concentration, and size of the inclusions. The dependence with respect to the nature and concentration of inclusions coincides with that obtained from a multiple-scattering homogenization method up to an inclusion concentration of approximately 50%.