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Biomedical subjects

Y An

Publications and source records attributed to Y An.

52 records · Page 3Linked to original sources
PubMed1992

Observation of proportionality of myoelectrical activity of anterior temporalis to masseter muscle during clenching at varied jaw positions.

Twelve healthy subjects with an intact permanent dentition and normal occlusion were selected for sampling of myoelectrical activity of their left and right anterior temporal and masseter muscles during habitual clenching level in varied positions. The proportionality of normalized myoelectrical potentials of anterior temporal muscle to masseter muscle at ICP and RCP was greater than one, while the proportionality at PP was less than one. In the lateral position, the proportionality on the working side was approximately equal to that at RCP, while the proportionality on the non-working side was similar to that at PP. These results suggest that temporal muscle contraction can bring the mandible upward and backward whilst the masseter muscle can elevate the mandible upward and forward.

Action Potentials↗
PubMed1990

[Changes of adrenoceptor density in heart and brain and the reactivity of isolated pulmonary artery ring in atherosclerotic rabbit].

The alpha-adrenoceptor density in cerebral cortex and brain stem as well as the beta-adrenoceptor density in heart were measured by radioligand binding assay in normal rabbits (group 1), atherosclerotic rabbits (group 2) and atherosclerotic rabbits treated orally with aspirin 20 mg/kg daily for 16 wk (group 3). The results showed that the beta-receptor density and the KD values of the hearts among the 3 groups and the alpha-receptor density and KD of brain stem between groups 1 and 2 were not significantly different except that the alpha-receptor density in group 3 was decreased slightly. The number of alpha 1-receptor of cerebral cortex was decreased more in group 2 than that in group 3. The contractile responses of isolated pulmonary artery ring by NE were similar among the 3 groups but the reactivity to 5-HT in group 3 was increased significantly.

Animals↗
PubMed1990

Effects of purified compound (8501) on hyperlipidemia and the balance between thromboxane A2 and prostacyclin in rabbits.

New Zealand strain white male rabbits were divided into four groups to study the effects of 8501, extracted from a Chinese herb, on hyperlipidemia and the TXA2/PGI2 ratio in atherosclerotic rabbits. The results indicate that serum cholesterol and the levels of cholesterol and cholesteryl ester in aortic tissue were significantly increased in cholesterol-fed rabbits. The percentage of alpha-lipoprotein was significantly decreased and the aortic atherosclerotic plaque area was significantly increased. The data also demonstrate that the level of plasma TXB2 was markedly increased, while that of 6-keto-PGF1 alpha was significantly decreased. The TXB2/6-keto-PGF1 alpha ratio (T/6) was significantly increased. The decrease of 6-keto-PGF1 alpha occurred prior to the increase of TXB2. Compound 8501 not only lowered serum total cholesterol and aortic total cholesterol and cholesteryl ester but also antagonized the decrease of alpha-lipoprotein and atherosclerotic plaque formation. In addition, 8501 prevented the decrease of plasma 6-keto-PGF1 alpha and the increase of TXB2, and so the T/6 ratio was significantly decreased.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Changes in arachidonic acid metabolite patterns in alloxan-induced diabetic rats.

The vasodepressor responses to intravenous injections of arachidonic acid, and the formation of its metabolites, were studied in rats made diabetic 1 or 2 weeks after a 1-dose alloxan treatment. Arachidonic acid dose-dependently decreased the diastolic blood pressure in normal animals, but this hypotensive effect was significantly weaker in 2-week postalloxan-treated rats. Indometacin abolished arachidonic-acid-induced depressor responses in both normal and diabetic animals. Hypotension induced by sodium nitroprusside was of the same magnitude in non-diabetic and insulin deficient rats. Plasma levels of thromboxane B2 were significantly increased in both the 1- and 2-week diabetic rats, being greater in the latter group; those of 6-keto-PGF1 alpha remained unchanged during the 2-week diabetic period. It is concluded that the attenuation by diabetes of depressor responses to arachidonic acid could be due to changes in the thromboxane/prostacyclin balance, with thromboxane formation being elevated whereas prostacyclin generation remains unaffected.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

[Molecular evolution of AdoMet synthetase by DNA recombination with a novel separate-mixing method].

We describe a new approach to in vitro DNA recombination termed Separate-Mixing method in this study. The reaction process of this method consists of two stages: at the first stage the reaction was implemented in two parallel teams, which generated random recombination by template-switching of growing polynucleotides from primers in the presence of unidirectional single-stranded DNA fragments used as templates, and then both teams were mixed together for further extension and recombination of DNA sequences at the second stage. Because of the particular strategy, the reaction process was also accompanied by the other two processes of DNA shuffling and StEP simultaneously. Two AdoMet synthetase genes sam2 from Saccharomyces cerevisiae and metK from Escherichia coli, which have only 56% homology on the DNA level were used for recombination with Separate-Mixing method. DNA recombination was available after a single round of reaction. With sequencing of 10 randomly selected recombinants, no unshuffled parental clone was found, and also no unexpected insertion, deletion or rearrangement was detected. An evolved gene sam' was obtained after screen and selection, which could obviously increase the accumulation of AdoMet in S. cerevisiae.

Directed Molecular Evolution↗