Biomedical subjects

Yongsheng Chen

Publications and source records attributed to Yongsheng Chen.

5 recordsLinked to original sources

PubMed2003

Synthesis and structure-activity relationships of thieno[2,3-d]pyrimidine-2,4-dione derivatives as potent GnRH receptor antagonists.

The synthesis and SAR studies of thieno[2,3-d]pyrimidine-2,4-diones as human GnRH receptor antagonists to treat reproductive diseases are discussed. It was found that the 2-(2-pyridyl)ethyl group on the 5-aminomethyl functionality of the core structure was a key feature for good receptor binding activity. SAR study of the 6-(4-aminophenyl) group suggests that hydrophobic substituents were preferred. The best compound from this series had binding affinity (K(i)) of 0.4 nM to the human GnRH receptor.

Pyrimidinones↗

PubMed2003

Synthesis and photochromic properties of molecules containing [e]-annelated dihydropyrenes. Two and three way pi-switches based on the dimethyldihydropyrene-metacyclophanediene valence isomerization.

The syntheses of several new simple negative, a simple positive, and multiple negative photochromes containing the dihydropyrene-cyclophanediene photochromic system are described. The photo-openings of the negative photochromes, the [e]-annelated benzo (7), naphtho (9), anthro (11), furano (19), and triphenyleno (15) derivatives of the parent 2,7-di-tert-butyl-trans-10b,10c-dimethyl-dihydropyrene (5), as well as its 4,5-dibromo derivative (13), are described to give the corresponding cyclophanedienes, as well as their photoclosures and thermal closures back to the dihydropyrenes. These are compared to the results obtained for the positive photochrome dibenzo[e,l]dihydropyrene (21) and to the bis(dihydropyreno)chrysene (44) and the (dihydropyrenobenzo)(benzo)metacyclophanediene (47) photochromes, which have more than one photochromic switch present and thus have more than a simple "on-off" state. Thermodynamic data are obtained for the thermal closing reactions. The anthrodihydropyrene (12) has the fastest thermal closing (tau(1/2) = 20 min), while the furanodihydropyrene (19') has the slowest (tau(1/2) = 63 h) at 46 degrees C. An electrochemical readout of the state of the switch is demonstrated for the benzodihydropyrene (7).

Journal Article↗

PubMed2003

Effects of thyroxine on cardiac function and lymphocyte beta-adrenoceptors in patients with chronic congestive heart failure.

OBJECTIVE: To explore the effects of thyroid hormone (TH) on cardiac function and peripheral lymphocyte beta-adrenoceptors (beta-ARs) of patients with chronic congestive heart failure (CHF). METHODS: Twenty-eight patients with class III or IV advanced CHF due to dilated cardiomyopathy (DCM) or ischemic cardiomyopathy (ICM) were randomly divided into groups A and B. L-thyroxine (L-T(50)) was administered to group B. Exercise tolerance, chest X-rays, and echocardiographic parameters were obtained before and after one month of treatment, Ficoll-hypaque solution was used to separate peripheral lymphocytes, and (125)I-pindolol radioligand binding was used to measure beta-AR levels in peripheral lymphocytes. RESULTS: L-T(50) therapy improved cardiac output [CO, (2.98 +/- 0.31)L/min vs (3.24 +/- 0.28) L/min, P < 0.01], left ventricular ejection fraction (LVEF, 26.21% +/- 3.21% vs 37.93% +/- 9.01%, P < 0.01), and decreased isovolumetric relaxation time (IVRT, 0.12 +/- 0.04 vs 0.10 +/- 0.02, P < 0.01). Serum TH levels and the maximal number of beta-AR binding sites (beta(max)) in peripheral lymphocytes were lower in patients with CHF than in normal healthy people, but L-T(50) administration induced a beta-AR up-regulation on peripheral lymphocyte surfaces. L-T(50) was well tolerated without episodes of ischemia or arrhythmia. There was no significant change in heart rate or metabolic rate. CONCLUSION: TH administration improves cardiac function and beta-AR expression in peripheral lymphocytes of patients with CHF.

Adult↗

PubMed2002

The Molecule Pages database.

The Alliance for Cellular Signaling (AfCS)-Nature Molecule Pages will be a comprehensive database of key facts about more than 3,000 proteins involved in cell signalling. Each entry will be created by invited experts and be peer-reviewed. Alongside the large-scale experiments being conducted by the AfCS scientists, the wealth of information contained in this database offers the potential of accelerating the pace of discovery in signal transduction research.

Automation↗

PubMed2002

Expeditious syntheses of two carbohydrate-linked cisplatin analogs.

The syntheses of two carbohydrate-linked cisplatin analogs, namely lacto- and alpha-Gal-cisplatin, are described. A fusion enzymatic approach was used to create the diazido-alpha-Gal trisaccharide intermediate in the synthesis of alpha-Gal-cisplatin.

Carbohydrate Sequence↗