Biomedical subjects

Yu Dong

Publications and source records attributed to Yu Dong.

23 records · Page 2Linked to original sources

PubMed2003

Analysis of glucose and lactate in hippocampal dialysates of rats during the operant conditioned reflex using microdialysis.

Changes of extracellular glucose and lactate in hippocampus for freely moving rats during the operant conditioned reflex were examined simultaneously. Samples of the dialysate were assayed for both glucose and lactate using in vivo microdialysis and a microbore flow injection analysis-immobilized enzyme reactor-electrochemical detection (FIA-IMER-ECD) system. Microdialysis samplings were conducted in a Skinner box where lights were delivered as conditioned stimuli (CS) paired with foot shocks as unconditioned stimuli (US). In the treatment group the concentration of glucose and lactate showed no fluctuations during the whole process. However, in the control group in which the rats were exposed to many foot shocks, lactate levels decreased by 19% below baseline during the behavioral session and glucose showed a delayed decrease (by 18%). Compared with glucose, lactate can immediately indicate the dynamic changes in brain.

Animals↗

PubMed2003

Effects of salicylate on serotoninergic activities in rat inferior colliculus and auditory cortex.

In vivo microdialysis offers a unique approach to monitor biochemical events related to brain function and metabolism, and has been used extensively in many systems to measure the release of endogenous transmitters and other neuroactive substances during normal and pathological conditions. The characterization of neurotransmitters' changes induced by salicylate in the inferior colliculus (IC) and the auditory cortex (AC) may provide insight into the action of salicylate on the auditory system and, through this, provide a better understanding of neurological mechanism of salicylate-induced tinnitus. In the present study, the effect of salicylate on 5-HT system in IC and AC has been monitored by microdialysis in salicylate-induced tinnitus animal models. Glucose and lactate levels in IC and AC were significantly increased after application of salicylate (350 mg/kg, i.p.), indicating a salicylate-related increase in regional neuronal activity. The 5-HT level increased to a maximum of 268+/-27% basal level in IC 2 h after application and of 277+/-24% basal level in AC around 3 h after application. These data suggest that the increases of 5-HT levels in IC and AC may be involved in the tinnitus generation.

Animals↗

PubMed2003

[Study of neurological mechanism of lidocaine's suppression to tinnitus via microdialysis].

OBJECTIVE: To elucidate the neurological mechanism of lidocaine's suppression to tinnitus. METHODS: Thirty-four Wistar rats weighing 300-350 grams were randomly divided into IC group (n = 17) and AC group (n = 17), according to microdialysis region. Each group was randomly subdivided into saline treatment group (n = 4), salicylate treatment group (n = 6), and salicylate + lidocaine treatment group (n = 7). Using in vivo microdialysis technique coupled with microbore HPLC-electrochemical detection, the present study first monitored the 5-HT release in IC and AC in salicylate-induced tinnitus animal models, and then, examined the effects of lidocaine on salicylate-induced 5-HT changes in IC and AC. The statistical analysis was performed using two-way ANOVA for repeated measures of raw data with time and treatment condition as main effects. Individual time-point values between no more than two groups were compared with the unpaired Student's t-test. The accepted level of significance was 0.05, two-tailed. RESULTS: The 5-HT level increased to a maximum of 268% +/- 27% (mean +/- s) basal level in IC 2 h after salicylate application and of 277% +/- 24% basal level in AC around 3 h after application. And then, the 5-HT level gradually decreased to 157% +/- 16% of baseline in IC and 180% +/- 18% of baseline in AC by the end of the sixth hour. Saline did not alter the IC and AC dialysate 5-HT level in control rats. Two-way ANOVA with repeated measures indicated a significant effect of the condition factor [F (1, 8) = 413.949, P < 0.000001 in IC group; F(1,8) = 192.184, P < 0.000001 in AC group]. The increases of 5-HT levels in salicylate treatment groups were significantly reduced to 85% +/- 8% basal level in IC and 92% +/- 26% basal level in AC after local infusion of 1% lidocaine (P < 0.05). Compared with corresponding control value at that time (unpaired student t-test). Two-way ANOVA with repeated measures showed a significant difference between the salicylate group and salicylate + lidocaine group [P < 0.000001 with F(1, 11) = 329.267 for the condition factor in IC subgroup; P < 0.000001 with F(1, 11) = 133.844 for the condition factor in AC subgroup]. CONCLUSION: The suppression of lidocaine to tinnitus may be associated with the decrease of 5-HT level in IC and AC.

Animals↗

PubMed2002

The phosphatidylinositol-3 kinase pathway is not essential for insulin-like growth factor I receptor-mediated clonogenic radioresistance.

The insulin-like growth factor I receptor (IGF-IR) is known to induce clonogenic radioresistance in cells following ionizing irradiation. To explore the downstream signaling pathways, we focused on the phosphatidylinositol-3 kinase (PI3-K) pathway, which is thought to be the primary cell survival signal originating from the receptor. For this purpose, R- cells deficient in the endogenous IGF-IR were used as a recipient of the human IGF-IR with or without mutations at potential PI3-K activation sites: NPXY950 and Y1316XXM. Mutants with double mutation at Y950/Y1316 exhibited not abrogated, but reduced activation of IRS-1, PI3-K, and Akt upon IGF-I stimulation. However, the mutants had the same clonogenic radioresistance as cells with wild type (WT) receptors. Neither wortmannin nor LY294002, specific inhibitors of PI3-K, affected the radioresistance of cells with WT receptors at concentrations specific for PI3-K. Collectively, these results indicate that the PI3-K pathway is not essential for IGF-IR-mediated clonogenic radioresistance.

Animals↗

PubMed2002

[Determination of aspirin and free salicylic acid in lysinipirine injection by high performance liquid chromatography].

The contents of aspirin and free salicylic acid in lysinipirine injection were determined by high performance liquid chromatography (HPLC). A Hypersil BDS C18 column was used with the mobile phase of methanol-water-acetic acid (35:65:3, volume ratio) and the detection wavelength of 280 nm. The average recoveries of aspirin and salicylic acid added were 99.27% (RSD = 0.8%) and 99.61%(RSD = 1.3%), respectively. The calibration curves had good linearity in the range of 0.028 g/L -0.141 mg/L and 0.77 mg/L -3.85 mg/L, and the correlation coefficients were 0.9999 and 0.9998 for aspirin and salicylic acid respectively.

Anti-Inflammatory Agents, Non-Steroidal↗