Biomedical subjects

Yan Xing

Publications and source records attributed to Yan Xing.

30 records · Page 2Linked to original sources

PubMed2005

Highly efficient iridium catalyst for asymmetric transfer hydrogenation of aromatic ketones under base-free conditions.

[reaction: see text] Catalytic systems generated in situ from the chiral PNNP ligands with iridium or rhodium hydride complexes exhibited excellent catalytic activity and good enantioselectivity in the asymmetric transfer hydrogenation of aromatic ketones without added base. The best result was obtained in the IrH(CO)(PPh(3))(3)-ligand 2 catalytic system with up to 99% yield and 97% ee.

Journal Article↗

PubMed2005

[Effects of withdrawal of statins on nitric oxide production in vascular endothelial cells].

OBJECTIVE: To investigate the effects of withdrawal of statins on endothelial nitric oxide production in human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were treated with simvastatin or lovastatin (10(-6) mmol/L) for 24 hours, then the drugs were replaced by a medium. At 6, 12, 18 and 24 hours after stopping statin treatment, nitric oxide production was measured with Griess reagents. Levels of endothelial nitric oxide synthase (eNOS) mRNA were examined with reverse transcription polymerase chain reaction (RT-PCR). RESULTS: After 24 hours of incubation, both simvastatin and lovastatin increased the nitric oxide production by (173 +/- 33)% and (170 +/- 44)% respectively and the production of nitric oxide at 24 hours after withdrawal of statins decreased by (64 +/- 9)% and (49 +/- 10)% respectively. These effects of simvastatin and lovastatin on eNOS mRNA expression correlated with changes in nitric oxide production. CONCLUSIONS: Withdrawal of statins can decrease the production of nitric oxide and the expression of eNOS mRNA, which may account for high cardiovascular events rate in clinical study when statins treatment was stopped abruptly.

Cells, Cultured↗

PubMed2004

Cohort analysis of patients with localized, high-risk, extremity soft tissue sarcoma treated at two cancer centers: chemotherapy-associated outcomes.

PURPOSE: Patients with American Joint Committee on Cancer stage III soft tissue sarcoma (STS) have high risks of distant recurrence and death. The role of chemotherapy for these patients remains controversial despite several randomized trials and a meta-analysis. METHODS: We reviewed the treatments and outcomes of 674 consecutive adult patients presenting with primary stage III extremity STS between 1984 and 1999. Pre- or postoperative doxorubicin-based chemotherapy was used in a nonrandomized fashion in approximately half of this high-risk population. The objective of this review was to evaluate the impact of chemotherapy while accounting for known prognostic variables. RESULTS: Among 674 patients, 338 (50%) were treated with local therapy only, and 336 (50%) were treated with local therapy plus chemotherapy. The median follow-up for survivors was 6.1 years. Five-year local and distant recurrence-free interval probabilities were 83% and 56%, respectively, for the two groups combined. The 5-year disease-specific survival (DSS) rate was 61%. Cox regression analyses showed a time-varying effect associated with chemotherapy. During the first year, the hazard ratio associated with DSS for patients treated with chemotherapy versus no chemotherapy was 0.37 (95% CI, 0.20 to 0.69; P = .002). Thereafter, this hazard ratio was 1.36 (95% CI, 1.02 to 1.81; P = .04). CONCLUSION: It seems that the clinical benefits associated with doxorubicin-based chemotherapy in patients with high-risk extremity STS are not sustained beyond 1 year. These results suggest that caution should be used in the interpretation of randomized clinical trials of adjuvant chemotherapy that seem to demonstrate clinical benefits with relatively short-term follow-up.

Adult↗

PubMed2004

The Sac3 homologue shd1 is involved in mitotic progression in mammalian cells.

Saccharomyces Sac3 required for actin assembly was shown to be involved in DNA replication. Here, we studied the function of a mammalian homologue SHD1 in cell cycle progression. SHD1 is localized on centrosomes at interphase and at spindle poles and mitotic spindles, similar to alpha-tubulin, at M phase. RNA interference suppression of endogenous shd1 caused defects in centrosome duplication and spindle formation displaying cells with a single apparent centrosome and down-regulated Mad2 expression, generating increased micronuclei. Conversely, increased expression of SHD1 by DNA transfection with shd1-green fluorescent protein (gfp) vector for a fusion protein of SHD1 and GFP caused abnormalities in centrosome duplication displaying cells with multiple centrosomes and deregulated spindle assembly with up-regulated Mad2 expression until anaphase, generating polyploidy cells. These results demonstrated that shd1 is involved in cell cycle progression, in particular centrosome duplication and a spindle assembly checkpoint function.

Animals↗

PubMed2004

[Effects of the combined use of benazepril and valsartan on apoptosis in the kidney of rats with adriamycin-induced nephritic glomerulosclerosis].

The effects of the combined use of angiotensin converting enzyme inhibitor (ACEI) benazepril and angiotensin II type 1 receptor antagonist (AT1RA) valsartan on apoptosis and the expression of apoptosis-related proteins Fas and FasL in the kidney of rats with adriamycin-induced nephritic glomerulosclerosis was investigated. Uninephrectomy and the injection of adriamycin induced the rat model of glomerulosclerosis. Benazepril (6 mg/kg), valsantan (20 mg/kg), or benazepril (3 mg/kg) plus valsantan (20 mg/kg) was respectively delivered daily by gavage to the rats in three treatment groups for 12 weeks. Apoptosis was examined by means of terminal-deoxynucleotidyl transferase mediated d-UTP nick end labeling (TUNEL). Immunohistochemistry was adopted to detect the expression of Fas and FasL. Software of pathological analysis quantitated the levels of Fas and FasL. The results showed that as compared with those in the control group, the kidneys in the model group had more severe glomerulosclerosis, much more apoptotic cells and higher levels of expression of Fas and FasL. The degree of glomerulosclerosis, the number of apoptotic cells and the levels of expression of Fas and FasL were reduced by benazepril and valsartan. The combined use of benazepril and valsartan had the best therapeutic effect. It was concluded that benazepril and valsartan could suppress the excessive apoptosis of kidney cells by lowering the expression of the apoptosis-related proteins Fas and FasL, so as to postpone the process of glomerulosclerosis. The combined use of benazepril and valsartan has better therapeutic effect.

Angiotensin II Type 1 Receptor Blockers↗

PubMed2004

Sentinel lymph node biopsy following neoadjuvant chemotherapy: review of the literature and recommendations for use in patient management.

Breast cancer is a significant health problem worldwide and is one of the leading causes of cancer-related mortality in women. Preoperative chemotherapy has become the standard of care for patients with locally advanced disease and is being used more frequently in patients with early-stage breast cancer. Sentinel lymph node biopsy has shown great promise in the surgical management of breast cancer patients, but its use following preoperative chemotherapy is yet to be determined. Eleven studies have been published with respect to the accuracy of sentinel lymph node biopsy following neoadjuvant chemotherapy. Ten studies showed favourable results, with the ability to identify a sentinel lymph node in 84% to 98% of cases, and reported false negative rates ranging from 0% to 20%. The accuracy of sentinel lymph node biopsy following preoperative chemotherapy for breast cancer ranges from 88% to 100%, with higher rates when specific techniques and inclusion criteria are applied. The published literature supports the use of sentinel lymph node biopsy for assessment of the axilla in patients with clinically node-negative disease following preoperative chemotherapy.

Antineoplastic Agents↗

PubMed2004

[Detection and analysis of HAV-HEV, HGV infection in patients with viral hepatitis].

OBJECTIVE: To study the simple infection and super/co-infection of HAV-HEV, HGV in patients with viral hepatitis. METHODS: Using EIA method to detect anti-HAV IgM, HBV serum markers, anti-HCV IgM, anti-HDV IgM, anti-HEV IgM, anti-HGV IgM in viral hepatitis patients with different clinical types. RESULTS: Seventy-three percent patients (154/210) had HBV infection markers, twenty-nine percent patients (61/210) had HAV infection marker, eight percent patients (17/210) had HCV, HDV infection markers, ten percent patients (21/210) had HEV infection and seven percent patients (15/210) had HGV infection. Only nine percent patients (20/210) had viral hepatitis serum markers negative. In all clinical types, sixty-one percent patients had only one type hepatitis virus infection, thirty-two percent patients had two types of hepatitis virus super/co-infection, six percent patients had three types of hepatitis virus super/co-infection. Super/co-infection often occurred in patients who had cirrhosis or hepatic failure. CONCLUSION: HBV and HAV infection is very common in viral hepatitis patients, whereas HCV, HDV, HEV and HGV infection is relatively low; double super/co-infection of HAV-HEV, HGV frequently occurs in severe patients with viral hepatitis.

Antibodies, Viral↗

PubMed2004

[Expression of heat shock protein-70, estrogen receptor and progesterone receptor in ovarian carcinomas and the correlation between HSP70 and sex steroid receptor].

OBJECTIVE: This study was aimed to determine the expression of HSP70, ER and PR in ovarian carcinomas and to explore the relationship between HSP70 and sex steroid receptor. METHODS: The immunohistochemical way SP was performed to estimate the expression of HSP70, ER and PR in 41 cases of ovarian carcinomas and in 11 cases of normal ovarian tissue. RESULTS: The positive staining rate of HSP70 was 68.29% (28/41), which was remarkably higher than that in normal ovarian tissue (18.18%) (P<0.05). Furthermore, the expression rate of HSP70 was much higher in poorly differentiated ovarian carcinomas than in well differentiated ovarian carcinomas (P<0.05). ER positive staining was observed in 19 cases (46.34%), and PR in 24 cases (58.54%). ER and PR positive staining occurred more frequently in the group of HSP70 negative staining than in the group of HSP70 positive staining. related with the expression of PR (P<0.05). CONCLUSION: The expression of HSP70 was negatively related with the expression of PR (P<0.05).

Adenocarcinoma, Mucinous↗

PubMed2003

Randomized comparisons among health informatics students identify hypertutorial features as improving web-based instruction.

Hypertutorials optimize five features - presentation, learner control, practice, feedback, and elaborative learning resources. Previous research showed graduate students significantly and overwhelmingly preferred Web-based hypertutorials to conventional "Book-on-the-Web" statistics or research design lessons. The current report shows that the source of hypertutorials' superiority in student evaluations of instruction lies in their hypertutorial features. Randomized comparisons between the two methodologies were conducted in two successive iterations of a graduate level health informatics research design and evaluation course. The two versions contained the same text and graphics, but differed in the presence or absence of hypertutorial features: Elaborative learning resources, practice, feedback, and amount of learner control. Students gave high evaluations to both Web-based methodologies, but consistently rated the hypertutorial lessons as superior. Significant differences localized in the hypertutorial subscale that measured student responses to hypertutorial features.

Attitude to Computers↗

PubMed2002

Synthesis, properties and X-ray crystal structure of a new heteropolyacid supermolecular charge-transfer complex [(VB1)2DMFHPMo12O40.5DMF].

The title complex [(VB(1))(2)DMFHPMo(12)O(40).5DMF, VB(1) = vitamin B(1) (thiamine chloride), DMF = N,N-dimethylformamide] has been synthesized and characterized by elemental analysis, IR, UV-Vis, electron spin resonance, X-ray photoelectron spectroscopy and cyclic voltammetry methods. The X-ray crystal structure revealed that there is one independent molecule in the unit cell of the title complex that contains one mixed-valence heteropolyanion, two VB(1)(+) cations and six DMF molecules. The title complex possesses a centrosymmetrical arrangement in the unit cell, with the P atom at the symmetry center of the heteropolyanion and with eight O atoms surrounding the central P atom, such that two sets of PO(4) tetrahedra are formed. The PO(4) tetrahedra and MoO(6)(6-(7-)) octahedra are disordered in the heteropolyanion. The bond distances of P-O(a) and Mo=O(d) are in the ranges 1.57 (4)-1.70 (4) A and 1.61 (2)-1.67 (2) A, respectively.

Journal Article↗

PubMed2002

[Relationship between hepatitis G virus infection and hepatic failure].

OBJECTIVE: To study the pathogenic effect of hepatitis G virus (HGV) infection on hepatic failure. METHODS: Using the RT-PCR and EIA techniques to detect HGV RNA and anti-HGV in sera of hepatic failure patients and compare them with their liver function and mortality rates. RESULTS: There was no significant difference about the positive rates of HGV among acute hepatic failure, subacute hepatic failure and chronic hepatic failure groups (X(2)=2.54, P>0.05). The level of ALT in HGV-positive group was slightly lower than that in HGV-negative group. The concentration of bilirubin and globulin was higher in HGV-positive group than HGV-negative group, and the concentration of albumin in HGV-positive group was significantly lower than that in HGV-negative group (t=2.59, P<0.05). The mortality rate in HGV-positive group was significantly lower than that in HGV-negative group (X(2)=4.68, 0.01<P<0.05). CONCLUSIONS: The virulence of HGV is mild, and the HGV infection does not aggravate hepatic failure.

Adult↗

PubMedDate not supplied

Measuring quality of life in patients with melanoma: development of the FACT-melanoma subscale.

A systematic review of the literature on quality of life (QOL) in melanoma patients suggested an overwhelming need for a disease-specific subscale. A melanoma subscale for the Functional Assessment of Cancer Therapy (FACT-Melanoma) was developed to meet this need. This instrument was developed in three stages. In stage I, the literature was comprehensively reviewed, and over 300 cancer-specific items from the Functional Assessment of Chronic Illness Therapy (FACIT) item bank were examined to identify questions of potential relevance to melanoma patients. In stage II, 20 melanoma experts identified questions that were relevant to melanoma patients and that were to be included in a pilot questionnaire. In stage III, the pilot questionnaire and a semistructured interview to assess item comprehension, relevance, and overall content were administered to 40 patients with various stages of melanoma. In all, 97 items were culled from the literature and the FACIT item bank; after items were reviewed and evaluated, 25 questions were retained. Most patients considered the content of the pilot questionnaire to be relevant (95%), comprehensive (60%), and easy to understand (88%). After final revisions were made, the FACT-Melanoma tool included 24 items encompassing three QOL domains: 20 items relate to physical well-being, 3 to emotional well-being,and 1 to social well-being. The face and content validity of the FACT-Melanoma assessment tool has been confirmed in melanoma patients and by professionals. Formal validation and reliability testing of the questionnaire is being determined in a prospective cohort of melanoma patients.

Adult↗