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Biomedical subjects

Jian-Yong Chen

Publications and source records attributed to Jian-Yong Chen.

7 recordsLinked to original sources
PubMed2006

Preparation and characterization of novel nanocomposite films formed from silk fibroin and nano-TiO2.

This paper describes the synthesis and characterization of new regenerated silk fibroin (SF)/nano-TiO(2) composite films. The preparation method, based on the sol-gel technique using butyl titanate as oxide precursor, could avoid reagglomeration of the prepared nanoparticles. Samples were characterized mainly by X-ray diffraction (XRD), ultra-violet (UV) spectroscopy, atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The UV and AFM results indicated that TiO(2) nanoparticles could be well dispersed inside the SF film, and the size of TiO(2) was about 80nm. The XRD and FT-IR analysis implied that the formation of nano-TiO(2) particles may induce the conformational transition of silk fibroin to a typical Silk II structure partly with the increasing of crystallinity in the composite films. Compared to the pure SF films, the mechanical and thermal properties of composite films were improved, and the solubility in water was decreased due to the conformational transition of silk fibroin to Silk II structure.

Fibroins↗
PubMed2006

Effect of drug treatment on hyperplastic gastric polyps infected with Helicobacter pylori: a randomized, controlled trial.

AIM: To study the effects of drug treatment on hyperplastic gastric polyps infected with Helicobacter pylori (H pylori). METHODS: Forty-eight patients with hyperplastic gastric polyps (3-10 mm in diameter) infected with H pylori were randomly assigned to a treatment group (n = 24) which received proton-pump inhibitor (omeprazole or lansoprazole), clarithromycin, bismuth citrate and tinidazole, and a control group (n = 24) which received protective agent of gastric mucosa (tepretone). Patients underwent endoscopy and H pylori examination regularly before enrollment and 1-12 mo after treatment. RESULTS: Twenty-two patients in the treatment group and 21 in the control group completed the entire test protocol. In the treatment group, polyps disappeared 1-12 mo (average, 6.5+/-1.1 mo) after the treatment in 15 of 22 patients (68.2%) and H pylori infection was eradicated in 19 of the 22 patients (86.4%). However, 12 months after the study, no change in polyps or H pylori status was seen in any controls ((b)P<0.01). CONCLUSION: Most hyperplastic gastric polyps disappear after eradication of H pylori.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2004

Serotonin modulates hypothalamic neuronal activity.

Effects of serotonin (5-HT) on electrophysiological activities of single hypothalamic arcuate neurons in rat brain slices were observed by extracellular recording. The results showed that (1) of 385 arcuate neurons observed, the patterns of spontaneous firing were divided into 3 categories: "slow irregular" (46.0%), "fast continuous" (22.6%), and "bursting" firing (31.4%); (2) of 149 neurons tested for 5-HT, most (55.0%) responded to the drug by decreasing firing rate, 22.2% by increasing firing rate, 11.4% exhibit biphasic pattern, and 11.4% did not respond to 5-HT application; (3) substitution of low Ca2-high Mg2+ artificial cerebrospinal fluid (ACSF) for normal ACSF did not abolish the 5-HT-induced excitatory effect while it did abolish the 5-HT-induced inhibitory effect, suggesting the effect in latter cases was elicited by a Ca2+-dependent release of neuroactive substances; (4) cyproheptadine, a non-selective 5-HT receptor antagonist, antagonized the 5-HT-induced excitatory effect in all neurons tested, while pindolol, a 5-HT1A/1B receptor antagonist, antagonized the 5-HT-induced excitatory effect in 50% of neurons tested; (5) both cyproheptadine and pindolol antagonized the 5-HT-induced inhibitory effect; and (6) bicuculline, a GABAA receptor antagonist, antagonized the 5-HT-induced inhibitory effect. These results suggest that 5-HT may exert its excitatory effects directly through 5-HT1A/1B and other subtypes of 5-HT-receptors located on the surface of the neurons recorded, while its inhibitory effects are mediated indirectly through the activation of a local inhibitory GABAergic interneuron.

Action Potentials↗
PubMed2002

Serotonin excites arcuate neurons directly but inhibits them through intercalated GABAergic neurons.

Effects of serotonin (5-HT) on spontaneous discharges of single hypothalamic arcuate neurons were observed in rat brain slices by extracellular recordings. The results showed that (1) of 149 neurons selected randomly and tested for 5-HT application, 33 (22.2%) were excited, 82 (55.0%) were inhibited, and 34 (22.8%) showed biphasic responses or failed to respond; (2) substitution of low Ca(2+)-high Mg(2+) artificial cerebrospinal fluid (aCSF) for normal aCSF abolished the 5-HT-induced inhibitory effect but failed to affect the 5-HT-induced excitatory effect; (3) cyproheptadine, a non-selective 5-HT receptor antagonist, could block either the 5-HT-induced excitatory or inhibitory effects in all neurons tested; and (4) bicuculline, a GABA(A)-receptor antagonist, blocked the 5-HT-induced inhibitory effect. These results imply (1) 5-HT excites arcuate neurons through a mechanism that is insensitive to the decreased extracellular Ca(2+), suggesting a direct postsynaptic action of 5-HT on the 5-HT-receptors located in the membrane of the neurons recorded; and (2) 5-HT might elicit the inhibitory effect through a Ca(2+)-sensitive release of GABA from intercalated GABAergic local neurons that are excited first by 5-HT.

Animals↗
PubMed2002

Alkaloids from Menispermum dauricum.

The alkaloids, dechloroacutumidine and 1-epidechloroacutumine, together with three known alkaloids, acutumidine, acutumine, and dechloroacutumine, were isolated from the rhizomes of Menispermum dauricum and their structures established by spectral and chemical methods. The cytotoxicity of each compound against the growth of human cell lines was studied, and acutumine selectively inhibited T-cell growth.

Alkaloids↗
PubMed2002

Nitrotyrasacutuminine from Menispermum dauricum.

Nitrotyrasacutuminine, an unusual nitrated morphine-type alkaloid was isolated from the roots of Menispermum dauricum. Its structure was determined by various 2D spectra and chemical methods.

Alkaloids↗