Effects of ozone exposure on nuclear factor-kappaB activation and tumor necrosis factor-alpha expression in human nasal epithelial cells.

In this study we investigated a possible mechanism of the human airway inflammatory response to inhaled ozone (O(3)). Cultures of human nasal epithelial (HNE) cells, initiated from excised nasal turbinates and grown on collagen-coated Transwell tissue culture inserts, were exposed to 120, 240, or 500 ppb O(3) for 3 h. An electron spin resonance (ESR) signal that changed with time suggested free radical production in HNE cells exposed to O(3). Nuclear protein extracts were analyzed for the activated transcription factor NF-kappaB by electrophoretic mobility-shift assay (EMSA), and showed a small dose-response activation of NF-kappaB that coincided with O(3)-induced free radical production. Basal media were analyzed for the presence of tumor necrosis factor-alpha (TNF-alpha) using the enzyme-linked immunosorbent assay (ELISA). In cultures exposed to 120 ppb O(3), the mean TNF-alpha concentration was not significantly different from those exposed to air. However, exposure to 240 and 500 ppb O(3) significantly increased mean TNF-alpha expression, relative to controls, 16 h after exposure. These results support the hypothesis that the human airway epithelium plays a role in directing the inflammatory response to inhaled O(3) via free radical-mediated NF-kappaB activation.

In vivo 19F-NMR study of halothane distribution in brain.

Halothane distribution and elimination from rabbit brain was studied in vivo using 19F-NMR spectroscopy. Two exponential decay functions for the anesthetic were observed in the clearance curve. They are assigned to halothane in brain held in two distinct chemical environments characterized by different chemical shifts, and half-lives (25 and 320 min). A nonvolatile halothane metabolite with a half-life of several days was found to be present in rabbit brains. The in vivo results were corroborated by ex vivo experiments on excised brain tissue. Halothane was distributed in all of the major cell subfractions, whereas the metabolite was present predominantly in the cytoplasm.

Regulation of climacteric respiration in ripening avocado fruit.

Ripening of avocado fruit is associated with a dramatic increase in respiration. In vivo(31)P nuclear magnetic resonance spectroscopy revealed large increases in ATP levels accompanying the increase in respiration. Both glycolytic enzymes, phosphofructokinase, and pyrophosphate: fructose-6-phosphate phosphotransferase were present in avocado fruit with the latter activity being highly stimulated by fructose 2,6-bisphosphate. Fructose 2,6-bisphosphate levels increased approximately 90% at the onset of ripening, suggesting that the respiratory increase in ripening avocado fruit may be regulated by the activation of pyrophosphate:fructose-6-phosphate phosphotransferase by an increase in fructose 2,6-bisphosphate.

In vivo 19F-NMR study of isoflurane elimination from brain.

The time course of isoflurane elimination from rabbit brain was studied in vivo with 19F-NMR spectroscopy. Two exponential decay functions with different time constants were observed and assigned to two distinct brain compartments. Isoflurane has a 26 min time constant for one compartment (similar to a value of 25 min with halothane) but 174 min in the second one, compared with 320 min for halothane. The shorter half-life for isoflurane may be due to lower solubility of this agent in brain tissue. Comparison of isoflurane 19F chemical shifts in solvents in isolated brain lipids and in whole brain tissue indicates that the anesthetic present in the brain exists in a single environment (on the NMR time scale), which is a weighted average of both hydrophilic and hydrophobic environments.

Noninvasive lung water quantitation by 1H nuclear magnetic resonance spectroscopy.

Three models of volume-dependent pulmonary edema were used in rabbits. Changes in lung water were measured by proton (1H) nuclear magnetic resonance spectroscopy (NMR) using a surface coil system, topical magnetic resonance. The anesthetized rabbits were ventilated with high frequency jet ventilation to minimize lung motion, and the surface coil was placed on the rabbit chest wall over the right lung. The rabbit preparation was placed in an Oxford Research Systems TMR-32 20-cm bore magnet. There was a close correlation (r greater than or equal to 0.90) between the gravimetrically determined lung wet to dry weight ratios and the percent change in the spectral areas as measured with 1H NMR, in all 3 experimental models.

In vivo 31P-NMR in human muscle: transient patterns with exercise.

Evaluation of dynamic changes in pH and concentrations of adenosine 5'-triphosphate (ATP), phosphocreatine (PCr), and inorganic phosphate (Pi) during the transition from rest to steady-state exercise in the human has been methodologically limited. Previous work has relied on muscle biopsy of exercising subjects at different times in different exercise bouts. Chemical evaluation of metabolites has been hampered by continuing change in metabolic concentration during the biopsy procedure. Recently, Fourier-transformed 31P nuclear magnetic resonance (31P-NMR), employing surface coils, has made evaluation of phosphorus metabolites possible by noninvasive atraumatic means in human muscle. Relative concentrations of PCr, Pi, and ATP, together with pH, have been obtained with 31P-NMR from the flexor digitorum superficialis muscle on two occasions in four adult men during the transition from rest to exercise. [PCr] rapidly fell and was mirrored by a rise in [Pi]. The former temporarily exceeded the latter with the discrepancy apparently being absorbed by a transient rise in [ATP], which was itself mirrored by alteration in [H+].

Mobile domains in ribosomes revealed by proton nuclear magnetic resonance.

Ribosomes and subunits from eukaryotic and prokaryotic sources were studied by high-resolution proton magnetic-resonance spectroscopy. If all ribosomal components are firmly bound within the particle, then only broad spectra would be expected. However, relatively sharp resonances were found both in ribosomal subunits and in 70 or 80 S ribosomes. The regions of these mobile protein domains have been partially assigned in Escherichia coli ribosomes. Large and small ribosomal subunits were treated to remove selectively proteins L7/12 and S1, respectively. Sharp proton magnetic resonance spectra were not observed for the stripped large subunit showing that proteins L7/12 comprise the flexible protein region and that there is little other flexibility in the stripped subunit. Complete removal of S1 from the small subunit greatly reduced but did not abolish the sharp protein resonance peaks, indicating that protein S1 contains a substantial flexible component but that other flexible components remain in the stripped small subunit. Evidence for generality of these features of ribosome organization is provided by similar studies on ribosomes from eukaryotic sources.