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Biomedical subjects

Bo Qin

Publications and source records attributed to Bo Qin.

18 recordsLinked to original sources
PubMed2007

Enantioselective strecker reaction of phosphinoyl ketoimines catalyzed by in situ prepared chiral N,N'-dioxides.

The enantioselective Strecker reaction of N-diphenylphosphinoyl ketoimines has been achieved by use of in situ prepared chiral N,N'-dioxide catalyst from l-piperidinamide 3f and m-chloroperoxybenzoic acid (m-CPBA). Excellent yields (up to 99%) and high enantioselectivities (up to 92% ee) were obtained. In particular, in situ prepared catalyst with readily available chiral material made the procedure more convenient. Moreover, the l-piperidinamide 3f-derived N,N'-dioxide 9 could be recycled and reused at least five times without any loss of either catalytic activity or enantioselectivity.

Catalysis↗
PubMed2006

A different function for a member of an ancient and highly conserved cytochrome P450 family: from essential sterols to plant defense.

CYP51 sterol demethylases are the only cytochrome P450 enzymes with a conserved function across the animal, fungal, and plant kingdoms (in the synthesis of essential sterols). These highly conserved enzymes, which are important targets for cholesterol-lowering drugs, antifungal agents, and herbicides, are regarded as the most ancient member cytochrome P450 family. Here we present a report of a CYP51 enzyme that has acquired a different function. We show that the plant enzyme AsCYP51H10 is dispensable for synthesis of essential sterols and has been recruited for the production of antimicrobial compounds (avenacins) that confer disease resistance in oats. The AsCyp51H10 gene is synonymous with Sad2, a gene that we previously had defined by mutation as being required for avenacin synthesis. In earlier work, we showed that Sad1, the gene encoding the first committed enzyme in the avenacin pathway (beta-amyrin synthase), had arisen by duplication and divergence of a cycloartenol synthase-like gene. Together these data indicate an intimate evolutionary connection between the sterol and avenacin pathways. Sad1 and Sad2 lie within 70 kb of each other and are expressed specifically in the epidermal cells of the root tip, the site of accumulation of avenacins. These findings raise intriguing questions about the recruitment, coevolution, and regulation of the components of this specialized defense-related metabolic pathway.

Amino Acid Sequence↗
PubMed2006

Highly enantio- and diastereoselective Brassard type hetero-Diels-Alder approach to 5-methyl-containing alpha,beta-unsaturated delta-lactones.

Two efficient new chiral copper (II) Schiff base complexes were developed for the highly enantio- and diastereoselective HDA reaction of Brassard type diene 1b with aldehydes, to afford the corresponding 5-methyl-containing alpha,beta-unsaturated delta-lactone derivatives in moderate yields, high enantioselectivities (up to 99% ee) and excellent diastereoselectivities (up to 99:1 anti/syn). On the basis of the absolute configuration of 4a-4j disclosed by X-ray diffraction and CD analysis, a possible transition-state model for the enantio- and diastereoselective catalytic reaction has been proposed.

Lactones↗
PubMed2006

Development of a specific latex agglutination test based on a recombinant hemagglutinin protein to detect antibodies to H5 avian influenza viruses.

A latex agglutination test (LAT) was developed for rapid detection of antibodies to H5 avian influenza viruses (AIVs). The hemagglutinin protein of H5 AIV was covalently linked to carboxylated latex by ethyl-dimethyl-amino-propyl carbodiimide to prepare the sensitized latex beads. The LAT was evaluated with the hemagglutination inhibition (HI) assay as the reference test. The H5-LAT showed a sensitivity of 87.0% and specificity of 88.9% in detecting 126 serum samples from experimentally infected chickens and a sensitivity of 82.5% and specificity of 86% in detecting 587 field chicken serum samples from mostly vaccinated chickens. The agreement ratio between H5-LAT and HI was found to be 87.3% and 83.1% for the two groups of samples, respectively. Difficulty with background agglutination in stored chicken sera was overcome by serum pretreatment with either dried chicken liver powder or dilution buffer containing detergent Tween-20. The H5-LAT has advantages over a previously reported whole-virus LAT in terms of biosafety in preparation, chemical stability, and higher specificity. It is a rapid and simple test suitable for field monitoring of antibodies to H5-type AIV.

Animals↗
PubMed2006

[Construction and expression of fusion gene encoding Hyper-IL-6 in mammalian cells].

AIM: To construct and express fusion gene encoding Hyper-IL-6 in mammalian cells. METHODS: Using geneSOEing method, human sIL-6R cDNA was fused with IL-6 cDNA by a linker rich in glycine through PCR technique and cloned into pIRES(2)-EGFP. The constructed plasmid was transfected into mammalian cells. The expression of fusion gene encoding Hyper-IL-6 was detected by GFP and RT-PCR and immunocytochemistry. RESULTS: The recombinant plasmid pIRES-HIL-6 was successfully constructed and expressed in mammalian cells. CONCLUSION: The success in construction and expression of human Hyper-IL-6 makes it possible to further study its biological functions.

Animals↗
PubMed2005

Catalytic asymmetric cyanosilylation of ketones by a chiral amino acid salt.

In this Communication, we describe the first highly enantioselective cyanosilylation of ketones catalyzed by simple chiral amino acid salt. A broad range of aromatic, alpha,beta-unsaturated, heterocyclic ketones catalyzed by l-phenylglycine sodium salt gave the corresponding trimethylsilyl ethers of cyanohydrins in 75-96% yields with 86-97% enantioselectivities. A catalytic cycle based on experimental phenomena and studies has been proposed to explain the origin of this activation. The reaction employed commercially available and fully recyclable catalysts and involves a simple experimental procedure.

Journal Article↗
PubMed2004

Highly enantioselective cyanosilylation of aldehydes catalyzed by novel beta-amino alcohol-titanium complexes.

The beta-amino alcohol 1b-Ti(Oi-Pr)(4) complex has been shown to catalyze the enantioselective cyanosilylation of aldehydes efficiently. In the presence of 5 mol % of 1b-Ti(Oi-Pr)(4) complex catalyst, the aromatic, conjugated, heteroaromatic, and aliphatic aldehydes were converted to their corresponding trimethylsilyl ethers of cyanohydrins in 90-99% yields with up to 94% ee under mild conditions.

Journal Article↗
PubMed2004

Enantioselective cyanosilylation of ketones by a catalytic double-activation method with an aluminium complex and an N-oxide.

Double-activation catalysis promises high catalytic efficiency in the enantioselective cyanosilylation of ketones through the combined use of a Lewis acid and a Lewis base. Catalyst systems composed of a chiral salen-Al complex and an N-oxide have high catalytic turnovers (200 for aromatic ketones, 1000 for aliphatic ones). With these catalysts, a wide range of aliphatic and aromatic ketones were converted under mild conditions into tertiary cyanohydrin O-TMS ethers in excellent yields and with high enantioselectivities (94% ee for aromatic ketones, 90% ee for aliphatic ones). Preliminary mechanistic studies revealed that the salen-Al complex played the role of a Lewis acid to activate the ketone and the N-oxide that of a Lewis base to activate TMSCN; that is, double activation.

Journal Article↗
PubMed2004

Removal of silicone oil from aphakia: use of a self-sealing corneal incision.

PURPOSE: To report and illustrate a modified and simple technique for silicone oil removal from aphakic eyes. DESIGN: Interventional case series. METHODS: Eighteen eyes of 18 patients who once had pars plana vitrectomy and lensectomy combined with silicone oil tamponade underwent silicone oil removal using a self-sealing corneal incision. RESULTS: All of the 18 silicone oil removal procedures performed had clear corneal incisions, which did not require suturing. CONCLUSIONS: Silicone oil can be removed successfully from aphakia using the self-sealing corneal incision under local anesthesia.

Adolescent↗
PubMed2004

[The efficacy of two type of membrane plasma separator on the treatment of patients with chronic severe hepatitis B].

OBJECTIVE: In order to compare the efficacy of two kinds of membrane plasma separator on the treatment of patients with severe hepatitis B. METHODS: 63 cases suffering from chronic severe hepatitis B were divided into two groups, 25 cases were treated with plasma exchange using Evacure-4A membrane plasma separator (A group) or 38 cases were using PS-06 membrane plasma separator (B group). Both of them also were treated with similar basic medical treatment. The level of serum total bilirubin, non-conjugated bilirubin, prothrombin time and albumin were tested at baseline and the end of the treatment with PE. RESULTS: Evacure-4A and PS-06 membrane plasma separators can effientively remove bilirubin, the levels of serum total bilirubin, non-conjugated bilirubin of all patients were significantly decreased after treated with PE. In A group, the level of serum total bilirubin, non-conjugated bilirubin decreased from (464.2+/-193.8)micromol/L to (279.4+/-158.7)micromol/L, (293.5+/-129.1)micromol/L to (175.5+/-106.7)micromol/L (t=5.45, 10.36, P<0.01) respectively. In B group, the level of serum total bilirubin, non-conjugated bilirubin decreased from (493.2+/-126.9)micromol/L to (299.7+/-96.5)micromol/L, (300.2+/-74.3)micromol/L to (171.5+/-53.1)micromol/L (t=5.17, 12.04, P<0.01) respectively. The level of serum albumin increased after treated with PE in A and B groups, to contrast with PS-06, the increasing percentage of albumin was higher when the patients were treated with PE using Evacure-4A membrane plasma separator [(8.3+/-0.7) % vs. (3.4+/-9.3) %, t = 2.76, P<0.01]. CONCLUSION: Evacure-4A membrane plasma separator may be better than PS-06 membrane plasma separator on the treatment of patients with chronic severe hepatitis B.

Adult↗
PubMed2004

[The effect of artificial support system on serum cytokine in chronic severe hepatitis].

OBJECTIVE: To explore the changes of cytokines including TNFalpha, TGFbeta1 and nitrogen monoxide, and endotoxin in the serum of chronic severe hepatitis after the treatment of ALSS, and to evaluate further the value of ALSS in the treatment of chronic severe hepatitis. METHODS: Forty two patients were screened. The changes of TNFalpha, TGFbeta1, nitrogen monoxide and endotoxin were detected respectively. The relationship between the cytokines and the severity and prognosis were further analyzed. RESULTS: ALSS was effective to decrease the serum concentration of cytokines. TNFalpha dropped from (481.57+/-229.33) pg/ml to (156.46+/-78.12) pg/ml (P < 0.05). TGFbeta1 from (44.09+/-31.73) ng/ml to (27.77+/-23.28) ng/ml (P < 0.01), endotoxin from (1.05+/-0.37) Eu/ml to (0.28+/-0.22) Eu/ml (P < 0.001). NO from (71.15+/-33.09) micromol/L to (58.11+/-29.30) micromol/L (P < 0.001). Before the therapy endotoxin was related with TNFalpha and total bilirubin, while after the therapy, NO was related with protime and aminonemia. CONCLUSION: High level of endotoxin and nitrogen monoxide in serum plays an important role in hepatocyte damage of chronic severe hepatitis. The changes of serum endotoxin TNFalpha, TGFbeta1 and nitrogen monoxide level in patients with chronic severe hepatitis can be used to judge the severity and prognosis of severe hepatitis. ALSS is a reliable hepatic support device for chronic severe hepatitis

Adult↗
PubMed2004

[The difference between the positive rate of anti-HCV in the patients with severe viral hepatitis detected by the first generation or second generation enzyme linked-immunosorbent assay].

OBJECTIVE: To compare the positive rate of antibody to hepatitis C virus (anti-HCV) in sera of patients with severe viral hepatitis between 1984-1990 year and 1997-2003 year. METHODS: Serum anti-HCV was detected by enzyme linked-immunosorbent assay (ELISA). It was detected by the first generation (1st) ELISA (Ortho Co. USA) in 79 cases of severe viral hepatitis during 1984-1990 year, and it was detected by the second generation (2nd) ELISA (Xiamen Xingchuang Co. China) in 251 cases of severe viral hepatitis during 1997-2003 year. RESULTS: The positive rate of serum anti-HCV was 51.9% detected by the 1st ELISA in 79 cases of severe viral hepatitis during 1984-1990 year, and it was 1.2% detected by the 2nd ELISA in 251 cases of severe hepatitis during 1997-2003 year (chi2 = 133.68, P </= 0.001). CONCLUSION: To compare with the positive rate of serum antibody to hepatitis C virus in severe viral hepatitis detected by the 1st ELISA, it was lower that detected by the 2nd ELISA

Adult↗
PubMed2004

[Corneal combined amniotic membrane transplantation for early severe alkali chemical injury of the eye].

OBJECTIVE: To investigate the effect of lamella corneal transplantation combined amniotic membrane transplantation for the early severe alkali burns of eyes. METHODS: Twenty-three eyes with an over second-degree acute corneal alkali injury in 2 weeks were treated by lamella corneal transplantation combined amniotic membrane transplantation. After the operation the patients were treated with an intense and prolonged regimen of topical steroids and topical and systemic vitamin C. All patients were followed up for 6-12 months. RESULTS: Seven eyes were cornea transparent, 10 semi-transparent, and 6 opaque in the 23 eyes, respectively. The visual acuity of 3 eyes was better than 0.3, that of 5 eyes was between 0.25 to 0.1, and that of the other 15 eyes was below 0.1. No eye was enucleated due to the corneoscleral melting. CONCLUSION: Lamella corneal transplantation combined amniotic membrane transplantation may clear away the necrotic tissues and cells of corneal or conjunctiva, prevent and reduce the complication, and improve the prognosis of the patients.

Adolescent↗
PubMed2003

[Cyclosporin A combined with dexamethasone in preventing and treating immune rejection after penetrating keratoplasty].

OBJECTIVE: To evaluate the efficacy of topical 1% cyclosporin A (CsA), 0.1% dexamethasone or 1% CsA combined with 0.1% dexamethasone in preventing and treating immune rejection after penetrating keratoplasty (PKP). METHODS: Eighty-six eyes from 86 PKP patients were randomly divided into 3 groups: (1) Thirty-one eyes were treated with 1% CsA and dexamethasone for 3 months. (2) Twenty-nine eyes were treated with 1% CsA for 3 months; (3) Twenty-six eyes were treated with 0.1% dexamethasone for 3 months. The rejected eyes of postoperation were given with the dexamethasone injection under conjunctiva and increased the frequency of CsA and dexamethasone eye drops. All patients were followed up for 1 to approximately 2 years. RESULTS: There was a statistical difference in the 3 groups in the postoperative immune rejection which occurred in 5 out of 29 (17.3% ) eyes treated with 1% CsA, 7 out of 26 (26.9%) treated with 0.1% dexamathasone, and 3 out of 31 (9.7%) with 1% CsA and dexamethasone. The immune rejection after PKP occurred in 15 eyes and 13 eyes were cured by sub-conjunctiva injection of dexamethasone combined with eye drops of 1% CsA and 0. 1% dexamethasone. CONCLUSION: The efficacy of CsA combined with dexamethasone topically is better than that of 1% CsA or 0.1% dexamethasone alone in preventing rejection episodes. It is effective to cure the graft rejection after PKP with sub-conjunctiva injection of dexamethasone combined with the eye drop of 1% CsA and 0.1% dexamethasone.

Adult↗
PubMed2002

[Clinical observation on argon green laser in the treatment of diabetic macular edema].

OBJECTIVE: To assess the clinical effect of argon green laser photocoagulation on diabetic macular edema. METHODS: Grid macular photocoagulation with argon green laser (lambda = 514 nm), 100-200 microns spot diameter and 0.1-0.2 s duration, was applied to 23 eyes of diabetic macular edema. Panretinal scatter photocoagulations, if needed, were carried out in the later therapy. The mean of the follow-up period was (9.3 +/- 4.1) months. Changes in macular edema and visual acuity as well were observed. RESULTS: Complete and partial resolution of macular edema occurred in 21 out of the 23 eyes and visual acuity improved or remained unchanged in 19 out of the 23 eyes. CONCLUSION: Grid macular photocoagulation with argon green laser is effective and relatively safe in the treatment of diabetic macular edema.

Aged↗