Comparison of the inhibitory effects of glucocorticoids on the expression of eotaxin in airway epithelial cell line BEAS-2B]

OBJECTIVE: Inhaled corticosteroids play a pivotal role in the treatment of asthma. To observe the mechanisms of glucocorticoids, we focused our study on the comparison of several glucocorticoids' effects on eotaxin expression in the airway epithelial cells. METHODS: Airway epithelial cell line BEAS-2B was cultured in vitro. Cells were preincubated with or without glucocorticoids (becromethasone dipropionate; BDP, budesonide; BUD, fluticasone propionate; FP) and stimulated with TNFalpha and/or IL-4. Protein levels of eotaxin in the supernatants of the cultured cells were determined by ELISA. RESULTS AND CONCLUSIONS: TNFalpha and IL-4 increased the levels of eotaxin in BEAS-2B cells. Combination of these cytokines synergistically upregulated the eotaxin expression as reported previously. Each glucocorticoid significantly inhibited the expression of eotaxin protein induced with TNFalpha and IL-4 and the compared efficacy was in order of FP>BUD>BDP. FP seemed most potent and the inhibitory effect was also observed with relatively low concentration such as 10 (-10)M. Taken together, the comparison of the potency of each glucocorticoid using airway epithelial cells may reflect the efficacy of these drugs in asthmatics.     

Electro-acupuncture stimulation effects on duodenal motility in anesthetized rats

The effect of electro-acupuncture stimulation (EAS) on duodenal motility was examined in anesthetized, artificially ventilated rats. EAS was applied to the abdominal area or to a hindpaw for 30 s at stimulus intensities of 0.1-10.0 mA with a stimulus frequency of 20 Hz. The duodenal motility was measured using the balloon method at a position about 1.5 cm caudal from the pylorus. Duodenal motility was inhibited by EAS at intensities of more than 5.0 mA (suprathreshold of group IV afferent excitation) when applied to the abdominal area. The duodenal inhibitory response existed after bilateral vagotomy or spinal transection, but was abolished by sectioning bilateral splanchnic nerves. Duodenal motility was facilitated by EAS at intensities of more than 2.0 mA (subthreshold of group IV, and suprathreshold for groups II+III afferent excitation) when applied to a hindpaw. The duodenal facilitatory response by EAS to a hindpaw existed after sectioning the splanchnic nerves, but disappeared after bilateral vagotomy or spinal transection. Furthermore, repetitive electrical stimulation of vagal efferent nerves enhanced duodenal motility, while repetitive electrical stimulation of the splanchnic efferent nerves inhibited the motility. It was concluded that the inhibitory response of duodenal motility elicited by EAS to the abdominal area is a spinal reflex response involving splanchnic inhibitory efferent nerves, and the enhanced response of duodenal motility by EAS to a hindpaw is a supraspinal reflex response involving vagal excitatory nerves.     

Identity of the 3'-terminal sequences in ten genome segments of silkworm cytoplasmic polyhedrosis virus

The double-stranded RNA genome of cytoplasmic polyhedrosis virus consists of ten different segments. The RNA was oxidized and then reduced with [³H]sodium borohydride to label the ribose moieties of 3′-terminal nucleosides. The labeled genome segments were separated from each other by polyacrylamide gel electrophoresis, and their 3′-termini were analysed by alkaline digestion and column chromatography. It was concluded that all ten genome segments have the identical 3′-terminal structure, carrying cytosine in one RNA chain and uracil in another chain:

In the course of experiments, some radioactive non-nucleosidic materials were found to be associated with every ³H-labeled RNA segment. These materials were released from RNA by dilute alkaline solution, and not adsorbed on charcoal.     

Efficacy of radiofrequency catheter ablation in a patient with sinus node reentrant tachycardia

We performed electrophysiological study and catheter ablation on a 62-year-old patient with supraventricular tachycardia(SVT). This SVT was reproducibly initiated and terminated by atrial stimulation during the electrophysiological testing. The P-wave morphology and atrial activation sequence of intracardiac electrograms were identical to those in normal sinus rhythm. SVT was terminated with carotid sinus massage that increased vagal tone, and for this reason, the reentry circuit of SVT could be localized in sinus node. On the basis of these findings, the SVT was diagnosed as sinus node re-entrant tachycardia and was successfully eliminated by radiofrequency catheter ablation. Radiofrequency catheter ablation would be effective in patients with sinus node reentrant tachycardia refractory to anti-arrhythmic drugs. It should, however, be performed with careful consideration to the influence of the sinus node.     

Depletion of mitochondrial DNA in HIV-1-infected patients and its amelioration by antiretroviral therapy

Mitochondrial DNA (mtDNA) of peripheral blood mononuclear cells (PBMCs) collected from Human immunodeficiency virus 1 (HIV-1)-infected patients and healthy controls were measured longitudinally using real-time polymerase chain reaction to evaluate the effects of antiretroviral agents on mtDNA synthesis in vivo and to assess the value of monitoring mtDNA in PBMCs to predict adverse events amongst these patients. MtDNA levels in PBMCs were significantly decreased in treatment-naive HIV-1-infected patients compared with healthy people. MtDNA levels were not only significantly correlated with CD4(+) T-cell count, but also inversely correlated with HIV-1 viral load. MtDNA levels in untreated patients and healthy controls were stable during the period of observation. On the other hand, amongst patients treated with regimens containing AZT/3TC or d4T/3TC, mtDNA increased during treatment and recovered to levels comparable to healthy controls. In contrast, mtDNA decreased immediately after the initiation of an AZT/ddC-containing regimen. We did not find a correlation between mtDNA levels and changes in clinical parameters. There was no significant difference in mtDNA levels between patients with and those without lipoatrophy. Furthermore, there was no obvious difference in mtDNA levels amongst those patients exhibiting signs and symptoms of peripheral neuropathy. In conclusion, the decrease in mtDNA levels in PBMCs amongst HIV-1-infected patients and its amelioration by antiretroviral therapy may suggest the influence of direct effects on mitochondria or mtDNA by HIV-1 infection. Further investigations are needed to elucidate the mechanisms contributing to decreased mtDNA and the value of mtDNA measurement in the care of HIV-1-infected individuals.     

Kupffer cell-mediated cytotoxicity against hepatoma cells occurs through production of nitric oxide and adhesion via ICAM-1/CD18

Rat Kupffer cell (KC)-mediated cytotoxicity against both thesyngeneic hepatoma cell line AH70 and hepatocytes was evaluatedby changes in mitochondrial function, and the possible roleof ICAM-1/CD18 in the interaction between the cells was studied.Rhodamine 123 fluorescence, a marker of the mitochondrial membranepotential, decreased in AH70 cells after co-culture with KC,while that in hepatocytes was unchanged by co-culture. Thisdecrease was blocked by anti-ICAM-1, anti-CD18 and the Inhibitionof nitric oxide synthesis. Cytometric studies demonstrated thatICAM-1 expression on AH70 cells increased after addition ofIFN-, IL-1ß, tumor necrosis factor (TNF)- or KC, whilein hepatocytes ICAM-1 was not increased. Anti-ICAM-1 pretreatmentinhibited the increase in ICAM-1 expression and the decreasein rhodamine 123 fluorescence on AH70 cells after co-culturewith KC. CD18 on KC was increased only after co-culture withAH70. TNF- but not IFN- was detected in the supernatant of co-culturebetween KC and AH70 cells, and this production was partiallyinhibited by anti-ICAM-1 and anti-CD18. The activity of Induciblenitric oxide synthase in Kupffer cells and the levels of nitritesand nitrates in the co-culture supernatant increased over time,and this increase was attenuated either by addition of NO synthesisinhibitors, anti-ICAM-1 or anti-CD18. These results indicatethat the rat KC causes mitochondrial dysfunction in cancer cellsvia the production of NO and cell-to-cell adhesion via ICAM-1/CD18has an Important role in this cytotoxic process.