Endothelin-1 and thromboxane A2 increase pulmonary vascular resistance in granulocyte-mediated lung injury

OBJECTIVE: To examine the pathophysiologic role of vasoactive eicosanoids and endothelin-1 in granulocyte-mediated effects in the pulmonary vasculature. DESIGN: Prospective experimental study in rabbits. SETTING: Experimental laboratory in a university teaching hospital. SUBJECTS: Thirty adult rabbits. INTERVENTIONS: The experiments were performed on 30 isolated and ventilated rabbit lungs that were perfused with a cell- and plasma-free buffer solution. MEASUREMENTS AND MAIN RESULTS: The pulmonary arterial pressure and the lung weight gain were continuously registered. Intermittently perfused samples were taken to determine endothelin-1 and thromboxane A2 concentrations. Six experiments without intervention served as the sham group. The granulocytes in the pulmonary circulation were stimulated with N-formyl-L-leucin-methionyl-L-phenylalanine (FMLP; 10(-6) M; control, n = 6). To investigate whether activated granulocytes influence the pulmonary vasculature via endothelin-1, the endothelin-A receptor antagonist LU135252 (10(-6) M) was added to the perfusate before FMLP injection (n = 6). The potential involvement of thromboxane A2 in granulocyte-endothelial interaction was investigated by pretreatment with the cyclooxygenase inhibitor diclofenac (10 microg/mL; n = 6). Activation of granulocytes resulted in an acute increase in pulmonary arterial pressure (>9 mm Hg), which was followed by a second delayed pressure increase after 60 mins (>14 mm Hg) and was paralleled by a massive generation of thromboxane A2 (>250 pg/ mL). Fifteen minutes after FMLP-injection, endothelin-1 was detectable in the perfusate. Pretreatment with the selective endothelin-A antagonist LU135252 significantly (p< .01) reduced the initial pressure response after FMLP stimulation, while diclofenac significantly reduced (p < .05) the delayed pressure increase. Using diclofenac (10 microg/mL) in conjunction with LU135252 (10(-6) M; n = 6) before FMLP injection significantly reduced the early and the delayed pressure increase. CONCLUSIONS: Activated granulocytes seem to enhance pulmonary vascular resistance via endothelin-1 and thromboxane A2. The endothelin-1 effects are probably mediated via endothelin-A receptors since the endothelin-A receptor antagonist LU135252 was able to suppress the early pressure reaction after FMLP injection, whereas the cyclooxygenase inhibitor diclofenac was able to reduce the second pressure increase.     

The secure-base hypothesis: Global attachment, attachment to counselor, and session exploration in psychotherapy.

This study explored J. Bowlby's (1988) secure-base hypothesis, which predicts that a client's secure attachment to the therapist, as well as the client's and the therapist's global attachment security, will facilitate in-session exploration. Volunteer clients (N = 59) and trainee counselors (N = 59) in short-term therapy completed the Experiences in Close Relationship Scale (K. A. Brennan, C. L. Clark, & P. R. Shaver, 1998) as a measure of adult global romantic and peer attachment orientations; the Client Attachment to Therapist Scale (B. Mallinckrodt, D. L. Gantt, & H. M. Coble, 1995) as a measure of attachment to counselor; the Working Alliance Inventory (A. O. Horvath & L. Greenberg, 1989) as a measure of working alliance; and the Session Evaluation Questionnaire-Depth Subscale (W. B. Stiles & J. S. Snow, 1984) as a measure of session depth. In line with Bowlby's hypothesis, the findings suggest that session depth is related to the client's experience of attachment security with the counselor and that counselor global attachment moderates the relationship between client global attachment and session exploration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formation and in situ sizing of gamma-Fe2O3 nanoparticles in a microwave flow reactor

Nanocrystalline gamma-Fe2O3 particles were produced in a microwave flow reactor. The reaction of iron pentacarbonyl [Fe(CO)5] with the plasma gases Ar/O2 to form nanosized particles was followed by in situ particle mass spectrometry. The particle mass spectrometer combines a nonintrusive sampling technique with a calibration-free mass determination. The influence of process parameters like microwave power, precursor concentration, and pressure on the particle size was studied. The results reveal a mean particle diameter in the range of 4-5 nm with a slight dependence on the process parameter. The geometric standard deviation of the measured size distribution was always between 1.1 and 1.2.     

Colorimetric sensor arrays for volatile organic compounds

The development of a low-cost, sensitive colorimetric sensor array for the detection and identification of volatile organic compounds (VOCs) is reported. Using an array composed of chemoresponsive dyes, enormous discriminatory power is possible in a simple device that can be imaged easily with an ordinary flatbed scanner. Excellent differentiation of closely related organic compounds can be achieved, and a library of 100 VOCs is presented. The array discriminates among VOCs by probing a wide range of intermolecular interactions, including Lewis acid/base, Br?nsted acid/base, metal ion coordination, hydrogen bonding, and dipolar interactions. Importantly, by proper choice of dyes and substrate, the array is essentially nonresponsive to changes in humidity.     

Formation and properties of ZnO nano-particles from gas phase synthesis processes

ZnO nano-particles have been synthesized in low pressure flow reactors utilizing Zn(CH₃)₂ as precursor. Two different synthesis routes have been employed. A low pressure flame reactor and a microwave reactor were used for synthesis of ZnO particle in Zn(CH₃)₂ doped H₂/O₂/Ar flames and Zn(CH₃)₂ doped Ar/O₂ plasmas, respectively. The particle formation process has been investigated in situ by a particle mass spectrometer. Also, sampled powders have been investigated ex situ by means of FT-IR, XRD, TEM, and UV-VIS. For both synthesis routes nanometer sized ZnO particles were found with particle diameters in the range between 4 to 8 nm. In cases of the flame reactor the results suggest a strong influence of water on the particle formation process.     

Efficiency and frequency of translational coupling between the bacteriophage T4 clamp loader genes

The bacteriophage T4 DNA polymerase holoenzyme is composed of the core polymerase, gene product 43 (gp43), in association with the "sliding clamp" of the T4 system, gp45. Sliding clamps are the processivity factors of DNA replication systems. The T4 sliding clamp comes to encircle DNA via the "clamp loader" activity inherent in two other T4 proteins: 44 and 62. These proteins assemble into a pentameric complex with a precise 4:1 stoichiometry of proteins 44 and 62. Previous work established that T4 genes 44 and 62, which are directly adjacent on polycistronic mRNA molecules, are-to some degree-translationally coupled. In the present study, measurement of the levels (monomers/cell) of the clamp loader subunits during the course of various T4 infections in different host cell backgrounds was accomplished by quantitative immunoblotting. The efficiency of translational coupling was obtained by determining the in vivo levels of gp62 that were synthesized when its translation was either coupled to or uncoupled from the upstream translation of gene 44. Levels of gp44 were also measured to determine the relative stoichiometry of synthesis and the percentage of gp44 translation that was transmitted across the intercistronic junction (coupling frequency). The results indicated a coupling efficiency of approximately 85% and a coupling frequency of approximately 25% between the 44-62 gene pair during the course of infection. Thus, translational coupling is the major factor in maintaining the 4:1 stoichiometry of synthesis of the clamp loader subunits. However, coupling does not appear to be an absolute requirement for the synthesis of gp62.     

Formulae and graphs of elastic stresses for design and analysis of U-shaped bellows

This paper presents equations describing the meridional and circumferential elastic stress levels at the root and crown due to external pressure and axial deflection of U-shaped bellows. The derivation is based on a statistical analysis of selected bellows configurations. The mathematical formulations and various graphical representations are proposed as aids to bellows design and analysis.