Biomedical subjects
Publications and source records attributed to Min Shi.
In this paper, we describe a practical, useful electrophilic aromatic nitration process in fluorous phase by using perfluorodecalin (C10F18, cis- and trans-mixture) as a fluorous solvent and perfluorinated rare earth metal salt [Yb(OSO2C8F17)3] as a catalyst for the electrophilic aromatic nitration.
The purposes of our study were to determine (1) the effects of intravenous (i.v.) nicotine on gastric mechanical function of anesthetized rats, (2) the CNS site of action of nicotine to produce these effects, (3) the CNS nicotinic acetylcholine receptor (nAChR) subtype(s) responsible for mediating the i.v. effects of nicotine, and (4) the brainstem neurocircuitry engaged by i.v. nicotine for eliciting its gastric effects. This was accomplished by monitoring intragastric pressure (gastric tone) and contractility of the fundus and antrum while administering five doses of i.v. nicotine and microinjecting nicotine into specific brainstem nuclei. Additionally, c-Fos expression in the brainstem after i.v. nicotine and pharmacological agents were used as tools to identify the CNS site and circuitry and reveal the nAChR subtype(s) mediating the gastric effects of nicotine. Using these experimental approaches, we found the following. (1) When given intravenously in doses of 56.5, 113, 226, 452, and 904 nmol/kg, nicotine elicited only inhibitory effects on gastric mechanical function. The most sensitive area of the stomach to nicotine was the fundus, and this effect was mediated by the vagus nerve at doses of 56.5, 113, and 226 nmol/kg. (2) The CNS site of action and nAChR subtype responsible were glutamatergic vagal afferent nerve terminals in the medial subnucleus of the tractus solitarious (mNTS) and alpha4beta2, respectively. (3) The brainstem neurocircuitry that was involved appeared to consist of a mNTS noradrenergic pathway projecting to the dorsal motor nucleus of the vagus (DMV). This pathway seems to be activated via nitriergic interneurons engaged by vagally released glutamate in the mNTS and results in alpha2 adrenergic receptor-mediated inhibition of DMV neurons projecting to the fundus and controlling gastric tone.
The reactions of propargylamine derivatives with carbon dioxide and carbon disulfide have been systematically examined in the presence of transition-metal catalysts. Pd(OAc)(2) is the best catalyst for the formation of the corresponding oxazolidinones. In addition, we found that, in the reaction of propargylamine with carbon dioxide catalyzed by palladium(0) metal catalyst in toluene, both oxazolidinone 1 and imidazolidinone 2 could be obtained under mild reaction conditions at the same time. The reaction of 1 with primary and secondary amines has been examined. A plausible reaction mechanism for the formation of 2 was proposed. In addition, in this paper, we first disclosed the ligand's effect on this reaction. Using PBu(t)(3) as a ligand with Pd(2)(dba)(3), 1 was exclusively formed in 90% yield.
A novel eco-safer protocol for the preparation of symmetric or asymmetric olefins directly from phosphonium salts under oxygen atmosphere in the presence of VO(acac)(2) (1.0 mol%) was developed.
C(2)-Symmetric chiral diethoxyphosphoramide 4, diethoxythiophosphoramide 5, and diisopropoxyphosphoramide 6 of (1R, 2R)-1,2-diaminocyclohexane were prepared by the reactions of diethoxyphosphinic chloride, diethoxythiophosphinic chloride, and diisopropoxyphosphinic chloride with (1R, 2R)-1,2-diaminocyclohexane, respectively. They were used as catalytic chiral ligands in the asymmetric addition reactions of diethylzinc to aldehydes in the presence of titanium(IV) isopropoxide to give the corresponding sec-alcohols with 43-70% ee. Chiral ligands 4 and 5 gave the sec-alcohols with opposite absolute configuration.
OBJECTIVE: To study the clinical characteristics of clear cell carcinoma of the ovary. METHODS: Forty three patients with clear cell carcinoma of the ovary and 51 patients with serous adenocarcinoma of the ovary who were admitted in Peking Union Medical College Hospital between 1984 to 2000 were analyzed retrospectively, and their chemosensitivities and the survival rates were compared. RESULTS: The percentage of early stage patients in the clear cell carcinoma of the ovary and the serous adenocarcinoma of the ovary was 14.4% and 3.8% respectively, the difference was significant (P < 0.005). In the late stage patients who underwent satisfactory cytoreductive surgery, the chemo-resistant rate (88.9%) in the clear cell carcinoma of the ovary was significantly higher than that (57.1%) of the serous adenocarcinoma of the ovary (P < 0.02), the 1-year survival rate (79.0%) in the clear cell carcinoma of the ovary was significantly lower than that (96.2%) of the serous adenocarcinoma of the ovary (P < 0.01). In the late stage patients who underwent unsatisfactory cytoreductive surgery, the chemo-resistant rate and the survival rate had no significant difference between the clear cell carcinoma of the ovary and the serous adenocarcinoma of the ovary (P > 0.05). CONCLUSIONS: There are more early stage patients with clear cell carcinoma of the ovary. We should conduct auxiliary therapy and close follow up to them after surgery. Clear cell carcinoma of the ovary is chemo-resistant to platinum-based chemotherapy and has poor prognosis.
OBJECTIVE: To study the therapeutic effects of radiotherapy combined with traditional Chinese medicine (TCM) on non-small cell lung cancer (NSCLC). METHODS: Ninety-two patients with NSCLC were randomly divided into combined treatment group (n=50) and radiotherapy group (n=42). The former group was given TCM in combination with radiotherapy, and the latter group received radiotherapy only. The adverse effects and quality-of-life (QOL) of all the patients were observed after the treatments. RESULTS: The incidence of adverse effects was much lower in combined treatment group than in radiotherapy group, and significantly greater improvement in QOL of the patients was observed in the former group (P<0.01). CONCLUSION: TCM in the combined treatment for patients with NSCLC can reduce the adverse effects of radiotherapy, and improve the life quality of the patients.
The growth promoting effects of seven animal serum transferrins from mammalian, aves, reptilia, amphibian and osteichthyes on mouse mammary tumor cell line GR2H6 in serum-free medium were compared by MTT assays. The results indicated that the mitogenic activities of the transferrins from different species were different, and this discrepancy was approximately parallel to their binding capacities with transferrin receptors on human placenta and GR2H6 cells.
In a chemically defined serum-free medium, insulin can stimulate DNA synthesis of the mouse mammary tumor-derived cell line GR2H6 up to 3 - 5 fold above the control group as measured by (3)H-thymidine incorporation. By growing GR2H6 cells in the 24-well and 96-well plates, a bioassay system for the growth promoting activity of insulin has been established. This method has the advantages such as easy operation, less time-consuming and suitable for measuring a large number of samples simultaneously. It may provide a novel model system for studies on the relationships between the growth promoting activity and the structure of insulin.
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PURPOSE: To identify causes of nonsyndromic cleft lip and palate in a Vietnamese population. METHODS: In this study, 175 families with at least one case of cleft lip and/or palate were studied using the candidate genes TGFA, MSX1, and TGFB3. RESULTS: Transmission distortion for alleles of MSX1 were demonstrated for the whole population and two missense mutations were identified, including one (P147Q) that is found in approximately 2% of the population. The P147Q appears to arise from a founder individual based on shared haplotypes in unrelated families. CONCLUSIONS: MSX1 contributes to nonsyndromic clefting in a Vietnamese population, and consistent with other studies, identifiable mutations in this gene cause about 2% of cases of nonsyndromic clefting.