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Biomedical subjects

Xin Zhou

Publications and source records attributed to Xin Zhou.

At least 55 records · Page 3Linked to original sources
PubMed2006

Measurement of the internal diameter of plastic tubes from projection MR images using a model-based least-squares fit approach.

Hyperpolarized (HP) 3He MRI is an emerging tool in the diagnosis and evaluation of pulmonary diseases involving bronchoconstriction, such as asthma. Previously, airway diameters from dynamic HP 3He MR images of the lung were assessed manually and subjectively, and were thus prone to uncertainties associated with human error and partial volume effects. A model-based algorithm capable of fully utilizing pixel intensity profile information and attaining subpixel resolution has been developed to measure surrogate airway diameters from HP 3He MR static projection images of plastic tubes. This goal was achieved by fitting ideal pixel intensity profiles for various diameter (6.4 to 19.1 mm) circular tubes to actual pixel intensity data. A phantom was constructed from plastic tubes of various diameters connected in series and filled with water mixed with contrast agent. Projection MR images were then taken of the phantom. The favorable performance of the model-based algorithm compared to manual assessment demonstrates the viability of our approach. The manual and algorithm approaches yielded diameter measurements that generally stayed within 1 x the pixel dimension. However, inconsistency of the manual approach can be observed from the larger standard deviations of its measured values. The method was then extended to HP 3He MRI, producing encouraging results at tube diameters characteristic of airways beyond the second generation, thereby justifying their application to lung airway imaging and measurement. Potential obstacles when measuring airway diameters using this method are discussed.

Algorithms↗
PubMed2006

Regularization network-based gene selection for microarray data analysis.

Microarray data contains a large number of genes (usually more than 1000) and a relatively small number of samples (usually fewer than 100). This presents problems to discriminant analysis of microarray data. One way to alleviate the problem is to reduce dimensionality of data by selecting important genes to the discriminant problem. Gene selection can be cast as a feature selection problem in the context of pattern classification. Feature selection approaches are broadly grouped into filter methods and wrapper methods. The wrapper method outperforms the filter method but at the cost of more intensive computation. In the present study, we proposed a wrapper-like gene selection algorithm based on the Regularization Network. Compared with classical wrapper method, the computational costs in our gene selection algorithm is significantly reduced, because the evaluation criterion we proposed does not demand repeated training in the leave-one-out procedure.

Algorithms↗
PubMed2006

Association study between fibronectin and coronary heart disease.

Fibronectin is a known chemoattractant for several cell types that play a role in the wound healing process, including fibroblasts, endothelial cells and macrophages. It also generates a scaffold that allows attachment of other extracellular matrix components. Large amounts of fibronectin have been detected in atherosclerotic plaques, suggesting that it may play a role in the pathogenesis of atherosclerosis. To examine the possible involvement of fibronectin in the etiology of atherosclerotic coronary heart disease, we analyzed four polymorphisms in the human fibronectin gene and determined the plasma fibronectin levels in patients with coronary heart disease (n = 109) and age- and gender-matched controls (n = 123) in Chinese Han people. No significant positive association was observed between these polymorphisms and coronary heart disease. The levels of circulating plasma fibronectin, however, were significantly lower in patients with coronary heart disease (mean +/- SD 245 +/- 87 mg/L) compared with controls (354 +/- 88 mg/L) (p < 0.001). The odds ratio (OR) for plasma fibronectin was 0.94 in a multivariate unconditional logistic regression model (OR = 0.94, 95% CI 0.91-0.96, p < 0.001). We conclude that, in our population, the four fibronectin gene polymorphisms detected are not associated with clinical coronary heart disease. Our data suggest that low circulating fibronectin levels might be a new marker of coronary heart disease.

Alleles↗
PubMed2006

[Status and influencing factors of mercury exposure in neonates and their mothers in Zhoushan].

OBJECTIVE: To investigate the status of mercury exposure of neonates and their mothers in Zhoushan City, and analyze the related influencing factors. METHODS: From Aug to Sep, 2004, 408 neonate-mother pairs were cluster sampled at the Third People's Hospital in Dinghai region, Zhoushan City, and a further investigation for the neurobehavioral development of these children was followed up in a year. The contains of mercury of 14 kinds of fish, 5 pieces of each kind bought in markets of Dinghai region were detected. RESULTS: The geometric mean of cord-blood Hg was 27.81 nmol/L (5.58 microg/L), while that of hair Hg of mothers was 1246.56 microg/kg. 69.9% of pregnant women had surpassed the RfD (reference dose, 0.1 microg/kg/day) for Hg intake. There was a strong correlation between hair and cord blood Hg levels (r = 0.821). The factors influencing cord-blood Hg levels were fish dinners, dwelling time, and fathers smoking or not, while those of hair Hg were fish dinners and dwelling time. The correlation between fish dinners and the cord blood Hg as well as hair Hg were of significance (r = 0.539, 0.481 respectively), the Hg levels were higher in more fish dinners (H = 119.805, 94.384 respectively). The mean fish Hg level at Dinghai region was low (< 0.1 mg/kg), and no samples were higher than 0.5 mg/L. Two samples of cutlassfish and dried eel contained higher Hg than the others, belonging to a middle level (0.1-0.5 mg/kg). CONCLUSIONS: Hg levels in neonates and pregnant women were generally below those considered hazardous, but the safety margin was narrow for some women and supporting efforts should be made to reduce mercury exposure. The main resource of Hg was from eating fish, and it is necessary to investigate the Hg levels in large samples, as to developing the fish advisories for susceptible people.

China↗
PubMed2006

[A study on the expression of myeloid cell leukemia 1 proteins and survivin and their relation with B cell apoptosis in non-Hodgkin's lymphoma].

OBJECTIVE: To explore the expression of myeloid cell leukemia 1 (MCL-1) proteins and survivin and its correlation with cell apoptosis as well as with the development and progression of B cell non-Hodgkin's lymphoma (B-NHL). METHODS: TdT-mediated dUTP nick end labeling and immunohistochemistry were used to study cell apoptosis and expression of MCL-1 proteins and survivin proteins in 43 patients with B-NHL and 10 with reactive hyperplasia (RH) lymphoid tissue. RESULTS: The positive rate of MCL-1 proteins and survivin proteins was 58.1% (25/43) and 69.8% (30/43) respectively. The expression of MCL-1 proteins was not detected in RH lymphoid tissue, but that of survivin was detected in 10.0% (1/10). The expression of MCL-1 proteins in aggressive B-NHL was higher than that in indolent B-NHL (70.0 % vs 30.8 %, P < 0.05). The expression of survivin in aggressive B-NHL was also higher than that in indolent B-NHL (80.0% vs 46.2%, P < 0.05). Apoptotic index (AI) was not correlated positively with the expression of MCL-1, but correlated positively with the expression of survivin (r = 0.429, P < 0.01). MCL-1 and survivin were correlated positively in B-NHL (r = 0.598, P < 0.001). CONCLUSIONS: MCL-1 proteins as family member of BCL-2 have no influence on apoptosis but survivin may participate in the regulation mechanism of B-NHL apoptosis. It is indicated that the two proteins with a close relationship may take part in the development and progression of B-NHL.

Adolescent↗
PubMed2006

[A multicentre study on the pathogenic agents in 665 adult patients with community-acquired pneumonia in cities of China].

OBJECTIVE: To investigate the pathogenic causes of community-acquired pneumonia (CAP) in adult patients in China, the relation of previous antibiotic use and the Pneumonia Patient Outcome Research Team (PORT) classification to microbial etiology, and the prevalence of drug resistance of common CAP bacteria. METHODS: A prospective study was performed on 665 consecutive adult patients with CAP at 12 centers in 7 Chinese cities during one year. The etiology of pneumonia was considered if one of the following criteria was met: (1) valid sputum sample yielding one or more predominant strains; (2) blood cultures yielding a bacterial pathogen; (3) seroconversion, a > or = 4-fold increase or decrease titers of antibodies to Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella pneumophila. Minimum inhibitory concentration (MIC) of respiratory tract isolates was determined using the agar dilution method. RESULTS: Pathogens were identified in 324/610 patients (53.1%) with valid serum samples and sputum cultures as follows: Mycoplasma pneumoniae (126, 20.7%), Streptococcus pneumoniae (63, 10.3%), Haemophilus influenzae (56, 9.2%), Chlamydia pneumoniae (40, 6.6%), Klebsiella pneumoniae (37, 6.1%), Legionella pneumophila (31, 5.1%), Staphylococcus aureus (23, 3.8%), Escherichia coli (10, 1.6%), Moraxella catarrhalis (8, 1.3%), Pseudomonas aeruginosa (6, 1.0%). Of 195 patients with a bacterial pathogen, an atypical pathogen was identified in 62 (10.2%) cases. The non-susceptibility rate of Streptococcus pneumoniae to penicillin, azithromycin, and moxifloxacin was 20.3%, 75.4% and 4.3% respectively. CONCLUSIONS: Atypical pathogens have important role in CAP, with Mycoplasma pneumoniae being the most common pathogen, and mixed infection of atypical pathogens with bacteria was found in 10.2% of the cases. Streptococcus pneumoniae and Haemophilus influenzae remain the most important bacteria for CAP. More than 75.0% of Streptococcus pneumoniae was resistant to macrolides and 20.3% was resistant to penicillin.

Adult↗
PubMed2006

[Study on the optimal ratio of autoskin and alloskin during mixed microskin grafting].

OBJECTIVE: To investigate the influence of different amount of allogeneic microskin in mixed grafting with certain quantity of autologous microskin on wound healing in rats. Methods Male Wistar rats served as alloskin donor rats. Forty female SD rats with full thickness skin defect were enrolled in the study, and they were randomly divided into four groups, i.e. group I (n=10, with allogeneic microskin graft at area expansion rate of 10:3); group II (n=10, with autologous microskin graft at area expansion rate of 10:1); group III (n=10, with mixed grafting of autologous and allogeneic microskin at area expansion rate of 10:1, respectively); group IV (n=10, with mixed grafting of autologous and allogeneic microskin at area expansion rate of 10:1 and 10:3, respectively). The wound healing rate, wound contraction rate and histological changes were observed at the 2, 3 and 4 post graft weeks (PGW). RESULTS: (1) In group I, there was mainly granulation tissue with some de novo epithelial cells appearing at the wound edge along with the rejection of grafted allogenous skin in the rat wound. In group II, there was still some granulation tissue remaining at 2 PGW due to insufficient amount of microskin. However, the wounds in the mixed grafting group appeared almost totally epithelialized. (2) Various amounts of mononuclear inflammatory cell infiltration and different degrees of angiectasis were observed in the dermal layer after the skin grafting in all groups, especially in group II and IV. There was thickening of the epithelial layer in all groups except group I. (3) The wound healing rate decreased obviously along with the development of rejection in group I at 2 to 4 PGWs. The wound healing rate was (55 +/- 26)% in group II, which was obviously lower than that in group III (88 +/- 6)% and in group IV (76 +/- 10)% at 3 PGWs (P < 0.01). (4) The contraction rate of the wound in group IV (69 +/- 7)% was much higher than that in group I (58 +/- 11)% at 3 PGWs (P < 0.05), and there was no difference among all the other groups. CONCLUSION: Wound healing can be obviously accelerated by mixing some autologous microskin with appropriate amount of alloskin. Moreover, certain amount of autologous microskin (expansion rate 10:1) mixed with the same proportion of allogeneic microskin seems to be more beneficial in promoting wound healing.

Animals↗
PubMed2006

[Influence of some topical antibiotics and FGF2, EGF and rhGH on the biological characteristics of fibroblasts in vitro].

OBJECTIVE: To investigate the influence of some topically used antibiotics (amikacin, gentamicin, chloromycetin and sulfamylon), basic fibroblast growth factor (FGF2) , epithelial growth factor (EGF) and recombinant human growth hormone (rhGH) on the growth of fibroblasts in vitro. METHODS: Fibroblasts were cultured and passaged. The cultured cells were then divided into control (routine culture of fibroblasts), amikacin (amikacin in respective dose of 0.021, 0.210, 2.100 mg/L), gentamicin (in respective dose of 5, 50, 500 mg/L) , chloromycetin (in respective dose of 0.01, 0.10, 1.00 mg/L), sulfamylon (in respective dose of 5, 10 g/L), FGF2 (2400 U/ml), EGF (2000 U/ml) and rhGH (0.016, 0.160, 1.600 g/L) groups. After the above agents were added to the culture medium respectively, the proliferation of the cultured fibroblasts was determined with MTT method, and the result was expressed as A (absorption) value. The cell cycle was determined with flow cytometry and the morphology of the cells was observed with inverted microscope. RESULTS: (1) MTT method: The A value of fibroblasts cultured with amikacin, gentamicin, chloromycetin and sulfamylon in various doses was obviously lower than that in control group (0.4553 +/- 0.0217, P < 0.05 or 0.01) , and the A value of sulfamylon group was the lowest in two doses (0.1013 +/- 0.0011 for 5 g/L and 0.0950 +/- 0.0041 for 10 g/L, P < 0.01). On the other hand,the A value in FGF2 and rhGH group(0.016 g/L) was much higher than that in the control (P < 0.05). However,theA value in EGF (both doses) and rhGH groups (0.160, 1.600 g/L) was close to that in control (P > 0.05). (2) Cell cycle determination: The proliferation index (PI) of fibroblasts cultured with amikacin in dose of 0.210 mg/L showed no difference compared to that in control (9.63 +/- 0.45)%, (P > 0.05). But the PI of fibroblasts cultured with FGF2, EGF and rhGF in dose of 0.016 g/L was increased significantly (46.76 +/- 2.33)%, (42.30 +/- 1.41)%, and (13.29 +/- 0.47)%, respectively, (P < 0.05 or 0.01). (3) Histological examination of the cells: The number of fibroblasts in elongated or spindle shape was larger, showing a blur contour but high transparency in control as well as in EGF and rhGH groups (both 0.160 and 1.600 g/L doses groups). The number of cells was lower in amikacin, gentamicin, chloromycetin and sulfamylon groups with sharp but irregular contour and lower transparency, and more granule-like materials and vacuoles in the cytoplasm. The cells in the FGF2 and rhGH (in dose of 0.016 g/L) groups exhibited dense with even distribution and slender or spindle shape and with more mitotic figures but blur contour and high transparency. CONCLUSION: Different kinds of the topically used therapeutic agents for burn wounds exert different influence on the biological characteristics of fibroblasts in vitro. The topically used agents for burn wounds should be carefully selected so that wound healing will be promoted and scar formation inhibited.

Anti-Bacterial Agents↗
PubMed2006

[Metabolites of R, S-1-(2-methoxyphenyl)-4-[3-(naphtha-1-yl-oxy)-2-hydroxypropyl]-piperazin in rat plasma].

AIM: To study the metabolites of R, S-1-(2-methoxypheyl)-4-[3-(naphthal-yl-oxy)-2-hydroxypropyl] -piperazine, (naftopidil, NAF), a novel antihypertensive drug in rat plasma. METHODS: The rat plasma samples were analyzed by LC/MS after oral administration of NAF. According to MS relativity of metabolites and parent compound (NAF) and metabolic rule of compound with similar structure, the structure of potential metabolites were postulated. Phase I metabolites were identified by HPLC/MS and by comparison with authentic standards, phase II conjugates were indirectly identified with beta-D-glucuronidase in presence or absence of glucuronidase selective inhibitor D-saccharric acid beta-1,4-Lactone. RESULTS: Phase I metabolites desmethyl-naftopidil (DMN), (phenyl) hydroxynaftopidil (PHN), (naphthyl) -hydroxy-naftopidil (NHN) were separated and identified in rat plasma by comparison with reference substances, phase II conjugates, NAF and NHN glucuronide conjugates were separated and tentatively identified by hydrolysis with glucuronidase, the aglycones, NAF and NHN, were identified in rat plasma. CONCLUSION: The major metabolic pathway of NAF in rat plasma should be the hydroxylation of the phenyl or nephthyl moiety of NAF and demethylation of NAF. Therefore, (naphthyl) hydroxyl-metabolite and NAF followed by conjugation with beta-glueuronic acid.

Animals↗
PubMed2006

[A novel APC gene germline mutation in a familial adenomatous polyposis pedigree].

OBJECTIVE: To detect the adenomatous polyposis coli (APC) gene germline mutation in the proband and her family members with familial adenomatous polyposis (FAP). METHODS: The diagnosis of a patient with FAP was validated by colonoscopy, pathology and the family history. The systematic screening with multiplex ligation-dependent probe amplification (MLPA), denaturing high-performance liquid chromatography (DHPLC) and DNA sequencing were carried out to detect APC gene germline mutations. RESULTS: A novel mutation c.1999 C >T (Q667X) of APC, which leads to premature termination of the protein, was identified in this family. This mutation manifested an aggressive form of FAP with early onset of colorectal adenocarcinoma and colonic adenoma. CONCLUSION: The mutation of APC Q667X is the cause of clinical phenotype of this family with FAP, and the prophylactic colectomy for the affected family members should be considered.

Adenomatous Polyposis Coli↗
PubMed2006

[Prolongation of the survival of skin allografts by intravenous injection of neuraminidase-treated donor bone marrow cells in rats].

OBJECTIVE: To optimize the best concentration of neuraminidase (Neu) that enhances the migration of neuraminidase (Neu)-treated donor bone marrow cells (dBMCs) to the liver, and observe the influence of short-term cyclosporin A(CsA) application combined with intravenous injection (i.v.) of Ne treated dBMCs on the survival of skin allografts. METHODS: The experiment consisted of two parts. For selection of an appropriate concentration of Neu, 26 female Wistar rats were randomly divided into four groups. The dBMCs were prepared by routine method and treated with four concentrations (0, 0.5, 1.0, 2.0 U/ml) of Neu at 37 degrees C for 30 min. The untreated and Neu-treated dBMCs were labeled by 99mTc, and injected via the tail veins to female Wistar rats in each group, respectively. After five hours, the radioactivity of various organs collected from sacrificed rats was measured by a gamma counter, and the values were expressed as percentage of total radioactivity of all organs from the same rat. To observe the survival of skin allograft, 23 male Wistar rats were randomly divided into control group, untreated dBMCs group and Neu-treated dBMCs group. All rats in each group were grafted with skin allografts from male Sprague-Dawley (SD) rats. The dBMCs from the same donor without and with Neu treatment by the concentration selected from the above experiment were injected via the tail veins of female Wistar rats in untreated dBMCs group and Neu-treated dBMCs group, respectively. Rats in untreated dBMCs group and Neu-treated dBMCs group received CsA (10 mg/kg) through intraperitoneal injection (i.p.) at 2 and 5 days post-grafting. Neither dBMCs or CsA were given in the control group. The survival of allograft skin in each group was checked and photographed daily after 5 days post operation. RESULTS: When the concentration of Neu was 1.0 U/ml, the percentage of dBMCs in liver was (75.3 +/- 9.8) %, which was obviously higher than that in 0 U/ml group [(58.9 +/- 4.2%)], (P < 0.01), indicating that the optimal concentration of Neu was 1.0 U/ml. The survival time of skin allografts in rats of Neu-treated dBMCs group was prolonged significantly in comparison with that of the rats in dBMCs group without Neu treatment (P < 0.01). The survival time in both dBMCs group and Neu-treated dBMCs group was longer that of control group (P < 0.01), and it was prolonged in Neu-treated dBMCs group compared with that in dBMC group. CONCLUSION: Administration of proper concentration of Neu can increase the affinity of dBMCs to the liver, and promote the Neu-treated dBMCs to migrate to liver. The intravenous injection of Neu-treated dBMCs combined with short-term CsA administration can delay the rejection of skin allografts in rats.

Animals↗
PubMed2006

[Comparison of tiotropium inhalation capsules and ipratropium metered dose inhaler in a randomized, double-blind, double-dummy, efficacy and safety study in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To compare the efficacy and safety between tiotropium capsule and ipratropium MDI in a 4 week treatment in patients with chronic obstructive pulmonary disease (COPD). METHODS: A multi-center, randomized, double blind, double dummy and parallel comparison clinical trial was conducted in 221 stable moderate to severe patients with COPD. They were randomized into tiotropium 18 microg once per day arm or ipratropium 2 puffs qid. arm for four weeks. The spirometry was conducted at 5 minutes pre-medication; and 30, 60, 120, and 180 minutes post-medication before; 2 weeks and 4 weeks after treatment. RESULTS: The forced expiratory volume in one second (FEV(1)) trough response, the primary endpoint, was significantly higher in the tiotropium arm than that of the ipratropium with (0.063 +/- 0.024) L (95% CI 0.016 - 0.111 L, t = 2.63, P = 0.009) after 4 weeks of treatment. Meanwhile the clinical evidences indicated the continuous improvement of bronchodilation in the tiotropium arm. Forced vital capacity (FVC) trough response was also significantly higher in the tiotropium arm 4 weeks after treatment with (0.133 +/- 0.047) L (t = 2.83, P = 0.005). By comparison with baseline, no significant differences were found between these two arms in the average change of FEV(1) as well as FVC 0 - 3 hours after inhalation (all P > 0.05). There was no significant difference in rescue medication consumptions (t = 0.60, P = 0.548). Adverse events occurred in 12 (10.9%) patients in the tiotropium arm and 18 (16.2%) in the ipratropium arm, without statistical difference (chi(2) = 1.326, P = 0.249). The major adverse event in the tiotropium group was dry mouth (5, 4.5%). No cardiac disorder or abnormal electrocardiogram was reported. CONCLUSION: The results indicated that tiotropium 18 microg once per day is more potent than ipratropium qid. in bronchodilation to COPD patients with the similar tolerance of ipratropium.

Aerosols↗
PubMed2005

A novel superporous agarose medium for high-speed protein chromatography.

A novel superporous agarose (SA) bead characterized by the presence of wide pores has been fabricated by water-in-oil emulsification using solid granules of calcium carbonate as porogenic agent. After cross-linking, the solid granules were removed by dissolving them in hydrochloric acid. Then, the gel was modified with diethylaminoethyl groups to create an anion exchanger, SA-DEAE, for protein adsorption. A homogeneous agarose (HA) bead was also produced and modified with DEAE for comparison. It was found that the porosity of SA-DEAE was about 6% larger than that of HA-DEAE. Moreover, both optical micrographs and confocal laser scanning microscopy (CLSM) of the ion exchangers with adsorbed fluorescein isothiocyanate (FITC) labeled IgG revealed the superporous structure of the SA medium. In addition, the SA-DEAE column had lower backpressure than the HA-DEAE column, confirming the convective flow of mobile phase through the wide pores. Due to the presence of the wide pores, more channels were available for protein transport and, furthermore, more diffusive pores in the agarose network were accessible for the protein approach from different directions. This led to 40% higher protein capacity and two times higher effective pore diffusivity in the SA-DEAE than in HA-DEAE. Moreover, an increase of the efficiency of the SA-DEAE column until a flow rate of 5 cm/min and the independency of the column efficiency at flow rates from 5 to 17.8 cm/min was found, indicating that intraparticle mass transfer was intensified by convective flow at elevated flow rates. Therefore, the chromatographic resolution of IgG and BSA was little affected up to a flow rate of 17.8 cm/min. The results indicate that the SA medium is favorable for high-speed protein chromatography.

Chromatography, Agarose↗
PubMed2005

Improved solvent-free microwave extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim.

Solvent-free microwave extraction (SFME) is a recently developed green technique which is performed in atmospheric conditions without adding any solvent or water. SFME has already been applied to extraction of essential oil from fresh plant materials or dried materials prior moistened. The essential oil is evaporated by the in situ water in the plant materials. In this paper, it was observed that an improved SFME, in which a kind of microwave absorption solid medium, such as carbonyl iron powders (CIP), was added and mixed with the sample, can be applied to extraction of essential oil from the dried plant materials without any pretreatment. Because the microwave absorption capacity of CIP is much better than that of water, the extraction time while using the improved SFME is no more than 30 min using a microwave power of 85 W. Compared to the conventional SFME, the advantages of improved SFME were to speed up the extraction rate and need no pretreatment. Improved SFME has been compared with conventional SFME, microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD) for the extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim. By using GC-MS system the compositions of essential oil extracted by applying four kinds of extraction methods were identified. There was no obvious difference in the quality of essential oils obtained by the four kinds of extraction methods.

Chromatography, Liquid↗
PubMed2005

Isolation and purification of flavonoid glycosides from Trollius ledebouri using high-speed counter-current chromatography by stepwise increasing the flow-rate of the mobile phase.

Three flavonoid glycosides including orientin, vitexin, quercetin-3-O-neohesperidoside and one unknown compound were isolated and purified by high-speed counter-current chromatography (HSCCC) and semi-preparative HPLC from Trollius ledebouri Reichb., a traditional Chinese medicine. Preparative HSCCC with a two-phase solvent system composed of ethyl acetate-n-butanol-water (2:1:3, v/v/v) was successfully performed by increasing the flow-rate of the mobile phase from 1.5 to 2.5 ml/min after 190 min. Consequently, 95.8 mg orientin, 11.6 mg vitexin, 9.3 mg unknown compound with purities of over 97% and one partially purified peak fraction (contained quercetin-3-O-neohesperidoside at 85.1% purity) were obtained from 500 mg of the crude extract. Then the partially purified fraction was further purified by reversed-phase semi-preparative high-performance liquid chromatography. The structure identification of all pure fractions was carried out by UV, MS, 1H NMR and 13C NMR.

Countercurrent Distribution↗
PubMed2005

[Mechanism linking atherosclerosis and type 2 diabetes: increased expression of scavenger receptor CD36 in monocytes].

BACKGROUND: We investigated the pathogenesis of atherosclerosis in diabetes, and detected the expression of scavenger receptor CD36 in monocytes in patients with type 2 diabetes. METHODS: According to the criteria by WHO, diabetic patients were classified into two groups: well controlled diabetic patients (WCP) and poorly controlled diabetic patients (PCP). The expression of CD36 protein and mRNA were evaluated by flow cytometry and reversal transcription polymerase chain reaction (RT-PCR). Plasma levels of accumulation of oxidized LDL (oxLDL) were directly measured by sandwich enzyme-linked immunosorbent assay (ELISA) method. RESULTS: Flow cytometry and RT-PCR showed that the mean fluorescence intensity (MFI) of CD36 in monocyte and CD36 mRNA were significantly higher in the PCP and WCP in comparison with healthy controls (P<0.01). CD36 MFI and mRNA in the PCP were increased by 78% and 36% compared to the WCP. In both groups, CD36 MFI and mRNA were significantly higher in patients with diabetic atherosclerosis in comparison with those without diabetic atherosclerosis (P<0.05). No significant difference was found in CD14 expression between the groups (P>0.05). The concentrations of plasma oxLDL were higher in the PCP group compared to WCP and control group (P<0.05), whereas oxLDL average values did not differ significantly between WCP and control groups (P>0.05). In the WCP and PCP groups, oxLDL levels were higher in patients with diabetic atherosclerosis than those without diabetic atherosclerosis (P<0.05). CONCLUSIONS: The increased expression of scavenger receptor CD36 may be one of the mechanism of accelerated atherosclerosis in diabetic. The poorly controlled diabetes patients are at higher risk for the vascular complications than the well controlled diabetic patients.

Adult↗
PubMed2005

Theoretical studies of the spectroscopic properties of [Pt(trpy)C[triple bond]CR]+ (trpy = 2,2',6',2"-terpyridine; R = H, CH2OH, and C6H5).

Electronic structures and spectroscopic properties of [Pt(trpy)C[triple bond]CR](+) (trpy = 2,2', 6',2' '-terpyridine; R = H (1), CH(2)OH (2), and C(6)H(5) (3) ) are studied by ab initio and DFT methods. The ground- and excited-state structures are optimized by the MP2 and CIS methods, respectively. The absorption and emission spectra in the dichloromethane solution are obtained by using TD-DFT (B3LYP) method associated with the PCM model. The calculations indicate that, for 1-3, the variation of the substituents on the acetylide ligand only slightly changes their structures in ground and excited states but leads to a sizable difference in the electronic structures. In both cases of absorption and emission, the energy levels of HOMOs for 1-3 are sensitive to the substituents on acetylide ligand and increase obviously with the introduction of the electron-donating groups; however, those of trpy-based LUMOs vary slightly. The lowest-energy emissions are attributed to triplet acetylide/Pt --> trpy charge transfer ((3)LLCT/(3)MLCT) transitions and the lowest-energy absorptions and emissions for 1-3 are red-shifted on the order of 1 < 2 < 3 when the electron-donating groups are introduced into the acetylide ligand. By comparison of the results obtained by using different functionals in TD-DFT method, the calculations indicate that the exchange-correlation functionals (B3LYP, B3P86 and B3PW91) involving Becke three parameter hybrid functionals are appropriate for the terpyridyl platinum(II) acetylide complexes to get the relatively satisfactory results for the absorption spectra. The underestimated excitation energies of lowest-lying absorption bands are probably due to insufficient flexibility in TD-DFT method to describe states with large charge transfer.

Journal Article↗