Biomedical subjects
Publications and source records attributed to Zhen Yang.
The palladium/bpy-catalyzed annulation of o-alkynylphenol with various aryl halides to generate diversified 2,3-diarylbenzo[b]furan is herein described. This method provides an efficient synthetic pathway for the combinatorial synthesis of conformationally restricted 2,3-diarylbenzo[b]furan for drug discovery.
[reaction: see text] A novel thiourea-based C2-symmetric ligand was synthesized, and its application in the palladium-catalyzed Heck and Suzuki coupling reactions of arenediazonium salts was evaluated. The reactions, which were performed at room temperature, without added base, and under aerobic conditions, produced product in 4 h with good yield. The corresponding arenediazonium salts were easily generated in one step from anilines.
OBJECTIVE: To study the role of heat shock protein 90 (HSP 90) in the formation of hyperdynamic circulation of portal hypertensive rats. METHODS: Animal model of portal hypertension was established by partial ligation of the portal vein among 20 SD rats (group P). Ten rats underwent sham operation (group S) Four weeks after the operation, the rats were killed and their mesenteric arteries and portal veins were obtained. The expression of HSP 90 in the portal veins and part of the superior mesenteric arteries was detected by Western blotting. Another mesenteric arteries underwent continuous perfusion with methoxamine (MTX, 30 and 100 micro mol/L) or acetylcholine (Ach). The perfusion pressure was monitored by a sensor. The concentration-response curves were examined in response to MTX and Ach infusion respectively. Then geldanamycin (GA) was infused; responses to MTX and ACh were repeated as described above. The endothelia of these arteries was denuded. After endothelial denudation was achieved, response to sodium nitroprusside (SNP) was examined. RESULTS: The expression of HSP 90 was much stronger in the group P than in the group S. The perfusion pressure of the mesenteric artery of the group P was 13.32 mm Hg +/- 0.55 mm Hg, significantly lower than that of the group S (17.33 mm Hg +/- 0.57 mm Hg, n = 10, P < 0.001). After the addition of MTX, the perfusion pressure of the mesenteric artery of the group P was 141.9 mm Hg +/- 7.6 mm Hg, significantly lower than that of the group S (181.1 mm Hg +/- 16.2 mm Hg, n = 8, P < 0.001). GA and 30 micro mol/L or 100 micro mol/L MTX were added successively into the perfusion fluid for the mesenteric superior artery of the group P, then the perfusion pressure became 106.7 mm Hg +/- 7.5 mm Hg or 124.9 mm Hg +/- 5.5 mm Hg, significantly higher than those of the mesenteric superior artery of the group P without addition of GA (60.9 mm Hg +/- 4.3 mm Hg, n = 5, P < 0.05 and 98.7 mm Hg +/- 4.7 mm Hg, n = 5, P < 0.05). GA and 100 micro mol/L MTX were added successively into the perfusion fluid for the mesenteric superior artery of the group S, the perfusion pressure became 151.2 mm Hg +/- 7.1 mm Hg, not significantly different from that of the mesenteric superior artery of the group S without addition of GA (149.8 mm Hg +/- 5.6 mm Hg, P > 0.05). With the addition of GA in advance, the ACh-dependent vasorelaxation of the isolated perfused rat mesenteric artery was significantly attenuated in comparison with the mesenteric artery without addition of GA into whose perfusion fluid (P < 0.05). However, GA did not affect the vasodilation of the ensothelium-neduded mesenteric artery in response to SNP. CONCLUSION: HSP90 is responsible for the hyperdynamic circulation in the portal hypertensive rats.
A novel ternary copper(II) complex, [Cu(phen)(L-Thr)(H2O)](ClO4) (phen=1,10-phenanthroline, L-Thr=L-threonine), has been synthesized and structurally characterized. The complex crystallized in a triclinic system with space group P1 , a=7.526(15) A, b=11.651(2) A, c=12.127(2) A, alpha=115.41(3) degrees , beta=102.34(3) degrees and gamma=91.33(3) degrees . The copper(II) center is situated in a distorted square-pyramidal geometry. At a concentration of 10(-6) mol L(-1), the complex exhibited potent cytotoxic effects against human leukemia cell line HL-60 and human stomach cancer cell line SGC-7901 with inhibition rates of over 90%, however, less pronounced effects were observed for human liver carcinoma cell line BEL-7402 and human non-small-cell lung cancer cell line A-549. The complex was shown to bind DNA by intercalation and cleave pBR322 DNA in the presence of ascorbate.
An open reading frame of the hyperthermophilic archaeon Aeropyrum pernix K1 APE2325, which composed of 474 bases, was cloned and expressed in Escherichia coli BL21 (DE3) Codon Plus-RIL. The recombinant protein was purified by Ni-chelation affinity chromatography. It showed a single band with a molecular mass of 18kDa in SDS-PAGE. The purified enzyme exhibited both phospholipase A(2) and esterase activities with the optimal catalytic temperature at 90 degrees C. The enzyme activity was Ca(2+)-independent. Kinetic analysis revealed its Km, k cat, and Vm for the p-nitrophenyl propionate substrate were 103microM, 39s(-1), and 249micromol/min/mg, respectively. The recombinant protein was thermostable and its half-life at 100 degrees C was about 1h.
HD2 (histone deacetylase) proteins are plant-specific histone deacetylases (HDACs). The Arabidopsis genome contains four HD2 genes, namely HD2A, HD2B, HD2C, and HD2D. We have previously demonstrated that HD2A, HD2B, and HD2C can repress transcription directly by targeting to promoters in planta. Here, we show that the N-terminal conserved motif (EFWG) and histidine 25 (H25), a potential catalytic residue, were important for the gene repression activity of HD2A. In situ hybridization indicated that HD2A, HD2B, and HD2C were expressed in ovules, embryos, shoot apical meristems, and primary leaves. Furthermore, all three genes were strongly induced during the process of somatic embryogenesis. HD2D mRNA was only detected in the stems and flowers with young siliques and may have adopted different functions. Using green fluorescent protein (GFP) fusions, we demonstrated that HD2A, HD2B, and HD2C accumulated in the nuclei of Arabidopsis cells. Overexpression of 35S::GFP-HD2A in transgenic Arabidopsis plants generated pleiotropic developmental abnormalities, including abnormal leaves, delayed flowering, and aborted seed development. The data showed that normal pattern of HD2 expression was essential for normal plant development and that HD2A, HD2B, and HD2C may be needed for embryogenesis and embryo development. Reverse transcriptase (RT)-PCR analysis revealed that a number of genes involved in seed development and maturation were repressed in the 35S::GFP-HD2A plants, supporting a role of HD2A in the regulation of gene expression during seed development.
Combining global and local search is a strategy used by many successful hybrid optimization approaches. Memetic Algorithms (MAs) are Evolutionary Algorithms (EAs) that apply some sort of local search to further improve the fitness of individuals in the population. Memetic Algorithms have been shown to be very effective in solving many hard combinatorial optimization problems. This paper provides a forum for identifying and exploring the key issues that affect the design and application of Memetic Algorithms. The approach combines a hierarchical design technique, Genetic Algorithms, constructive techniques and advanced local search to solve VLSI circuit layout in the form of circuit partitioning and placement. Results obtained indicate that Memetic Algorithms based on local search, clustering and good initial solutions improve solution quality on average by 35% for the VLSI circuit partitioning problem and 54% for the VLSI standard cell placement problem.
OBJECTIVE: To analyze relation between the use of corticosteroids in the treatment for severe acute respiratory syndrome (SARS) patients and arthralgia as a sequela. METHODS: Clinical date of 30 SARS patients without other diseases in whom corticosteroid was used were reviewed including total dosage, duration of use, the highest dosage and its duration, and speed of reduction in dosage. The information about arthralgia was investigated one month after discharge of SARS patients from the hospital. RESULTS: The average total dosage of methylprednisolone was (4 244.16+/-2 292.30) mg, and the duration of use of the treatment was (25.36+/-5.88) days (ranging from 12 to 35 days). The maximum dosage was (321.33+/-174.03) mg/d, and the duration of its use was (7.73+/-4.08) days. The speed of reduction of dosage of corticosteroids was (21.33+/-10.18) mg/d. There were 26 of 30 patients (86.67 percent) experienced arthralgia symptom during convalescence. In 3.6 percent of patients arthralgia occurred within one month after SARS, 53.85 percent of the patients experienced low-grade arthralgia. By unifactor analysis, the total dosage and its duration of use, the highest dosage and its duration, speed of reduction of dosage of corticosteroids were correlated with the degree of arthralgia, respectively. The duration of arthralgia was correlated with the total dosage, the duration of high dosage, and high dosage. Age was not correlated with either the degree or the persisting time of arthralgia. The degree of arthralgia was only correlated with the total dosage, and the duration of arthralgia was correlated with administration time of glucocorticosteroids by multifactor analysis. CONCLUSION: There is a dosage- effect relation between the degree of arthralgia and the total dosage of corticosteroid, and a time-effect relation between the duration of arthralgia and length of the use of corticosteroids.
OBJECTIVE: To study the antiviral effect and mechanisms of the liquid extract from Ceratostigma willmattianum against herpes simplex virus type 1 (HSV-1) in vitro. METHOD: C. willmattianum in various concentration was applied to different steps of HSV-1 replication cycle. 50% Tissue culture infective dose (TCID50), cytopathic effect (CPE), MTT staining method, dot blotting and Northern blotting analysis were used to estimate index of antiviral activity. RESULT: 50% Toxic concentration (TC50) was 1077 mg x L(-1), IC50 29.46 mg x L(-1) and therapeutic index (TI) 36.56 in C. willmattianum. TC50 330 mg x L(-1), 50% Inhibiting concentration (IC50) 9.12 mg x L(-1) and TI 36.18 in ACV by MTT staining method. The liquid extract from C. willmattianum had remarkable effect on inhibiting HSV-1 in vitro. Ceratostigma could interfere absorption of HSV-1 to Vero cells to prevent HSV-1 infectivity, inhibit HSV-1 gD DNA replication and HSV-1 gD mRNA expression. CONCLUSION: C. willmattianum possesses strong anti-HSV-1 activity in vitro. The antiviral mechanisms are related to inhibiting virus absorption, HSV-1 gD gene replication and HSV-1 gD gene transcription.
OBJECTIVE: The inverted "T" operation is a typical and classic method for breast hypertrophy. Although having good results, it leaves significant scar and tends to have bottom-out deformity with time. The purpose of this study is to introduce our experience in vertical mammaplasty. METHODS: The typical Lejour's design was used. The lower part of the breast was excised. The nipple-alveolar complex was elevated to a proper position with the superior dermal-glandular pedicle. Only vertical scar was left after the skin was closed. RESULTS: 24 patients were treated using this method. The results were satisfactory except unilateral nipple-alveolar complex necrosis occurred in one patient. Another patient had a minor revision for the dog-ear 6 months after breast reduction. CONCLUSIONS: Vertical reduction mammaplasty is effective with reduced scar and highly satisfactory results. It deserves recommendation.
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The total synthesis of wedelolactone, a naturally occurring direct inhibitor of IKK complex that can suppress LPS-induced caspase-11 expression, using a convergent synthetic approach, is described. The key steps involved in this synthesis include the palladium-catalyzed Sonogashira reaction and the palladium-catalyzed carbonylative annulation reaction. This approach allows access to diversified analogues of wedelolactone.
This paper reports a prototype for a standard connector between a microfluidic chip and the macro world. This prototype demonstrate a fully functioning socket for a microchip to access the outside world by means of fluids, data signals and energy supply. It supports up to 10 channels for the input and output of liquids or gases, as well as compressed air or vacuum lines for pneumatic power lines. The socket has built-in valves for each flow channel. It also contains 28 pins for the connection of electrical signals and power. Built-in valves make it possible to control the flow in each channel independently. A chip ( 11.0 x 11.0 x 0.9 mm) can be mounted into or dismounted from the socket with one touch. The fluidic connectors of the socket are designed to contact vertically on the top of chip. And the electrical connectors (the spring array) of that physically support the chip and contact lead pads at the bottom of chip. No adhesives or solders are used at any contact points. The pressure limit for the connection of working fluids was 0.2 MPa and the current limit for the electrical connections was 1 A. This socket supports both serial and parallel processing applications. It exhibits great potential for developing microfluidic systems efficiently.
Methyl protodioscin (1), otherwise known as 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-d-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22-methoxy-25(R)-furost-5-ene-3 beta,26-diol, has been synthesized for the first time from diosgenin through nine steps in an overall yield of 7.8%.
[reaction: see text] A novel catalytic system of AgOTs-CuCl(2)-TMEDA is described for the homocoupling of aliphatic acetylenes on solid support. It is the first observation that Ag(I)'s activating triple bond could facilitate Cu(II)-mediated oxidative acetylenic homocoupling. This study provides an efficient way to synthesize a diversified symmetrical bis-benzo[b]furan-linked 1,3-diyne library on solid support.
An efficient and facile synthesis of 4-substituted 2(5H)-furanones using palladium catalyzed cross-coupling reactions between 4-tosyl-2(5H)-furanone and boronic acids is reported herein.
The carcinogenic effects of 1,3-butadiene (BD), a chemical widely used in the rubber industry, are thought to be due to its epoxide metabolites. In humans, these epoxides are detoxified predominantly by hydrolysis, a reaction mediated by the microsomal epoxide hydrolase (mEH) enzyme. The mEH gene is polymorphic and the most common mEH coding-region variants detected in human populations are the two amino acid polymorphisms Tyr113His and His139Arg. Polymorphic amino acid substitutions at residues 113 and 139 in the human mEH protein can associate in four distinct combinations: Tyr113/His139, Tyr113/Arg139, His113/His139, and His113/Arg139. In vitro studies have shown that each of these genotypes has a unique mEH protein level that can affect net mEH enzymatic activity. In the current study, we examined the relationships among the genotypes involving these two polymorphisms and the mutagenic responses associated with occupational exposure to BD. We studied 49 nonsmoking workers from two styrene-butadiene rubber facilities in southeast Texas using the autoradiographic HPRT mutant lymphocyte assay as a biomarker of genotoxic effect. We genotyped the study participants simultaneously for both polymorphisms, using a multiplex PCR assay developed in our laboratory, and the subjects were assigned to a specific group based on the predicted mEH activity associated with their genotypes (low, intermediate, and high). In the study population, 67% were exposed to low BD levels of <150 ppb (measured by personal badge dosimeters) and 33% were exposed to >150 ppb (mean 2,244 ppb). In the BD low-exposure group, the mEH genotypes had no significant effect on the HPRT variant (mutant) frequency (Vf). In the high-exposure group (BD > 150 ppb), individuals with genotypes associated with low mEH activity had a significant (P < 0.05) 3-fold increase in HPRT Vf (Vf +/- SEM = 13.95 +/- 2.15 x 10(-6)) compared to high-activity individuals (4.41 +/- 1.19 x 10(-6)), and a 2-fold increase in Vf compared to intermediate-activity individuals (6.44 +/- 2.09 x 10(-6)). Our results indicate that mEH genotypes may play a significant role in human sensitivity to the genotoxic effects of exposure to BD.
To determine the role of NF-kappa B in ischemia reperfusion (I/R) injury of the rat liver, rats underwent partial hepatic ischemia and reperfusion. The left and median lobes of the liver were subjected to ischemia for 90 min followed by reperfusion for defined times. NF-kappa B activity was analyzed by electrophoretic mobility shift assay (EMSA). Semiquantitative reverse-transcriptase polymerase chain reaction was used to analyze TNF-alpha and ICAM-1 mRNA levels. Results showed during liver I/R injury, NF-kappa B activation was induced in a time dependent manner. NF-kappa B was activated within 1 h and 2 h after the initiation of reperfusion and decreased after 4 h. Messenger RNA expression of TNF-alpha and ICAM-1 were increased after the reperfusion of 2 h. It was concluded that during hepatic I/R injury, NF-kappa B was activated and could bind to special sequence in the promoters of budget genes, which can up-regulate the expression of TNF-alpha and ICAM-1 mRNA to result in ischemia reperfusion injury of the rat liver.