Biomedical subjects

Hong Zhang

Publications and source records attributed to Hong Zhang.

At least 343 records · Page 19Linked to original sources

PubMed2004

[In vitro antibacterial activity of cefdinir against isolates of respiratory tract pathogens in children].

OBJECTIVE: To study the in vitro antibacterial activity of cefdinir against clinical isolates of respiratory tract pathogens in Children. METHODS: MIC values of cefdinir against 380 strains were determined with E-test method and compared with those of cefaclor. RESULTS: All penicillin-susceptible Streptococcus pneumoniae (PSSP) strains were also susceptible to cefdinir and cefaclor. Both cefdinir and cefaclor were not active against penicillin-resistant SP (PRSP). Against penicillin-intermediate SP (PISP) the susceptibility rates of cefdinir and cefaclor were 70.1% and 57.4%, respectively. The activity of cefdinir and cefaclor against beta-lactamases negative Hemophilus influenzae (HI) was excellent, but the susceptibility rates of cefdinir and cefaclor against beta-lactamases positive HI were 85.0% and 70.0%, respectively with MIC(90) of 1.5 mg/L vs. 256.0 mg/L. Cefdinir presented higher activities and lower MIC values than cefaclor against Moraxella catarrhalis (MC), Group A streptococcus (GAS), methicillin susceptible staphylococcus aureus (MSSA), and extended spectrum beta-lactamases (ESBLs) negative Escherichia coli (E. coli) or Klebsiella pneumoniae (K. pn). Both cefdinir and cefaclor were not susceptible to ESBLs positive E. coli and K. pn. CONCLUSIONS: Cefdinir exhibits excellent activity against PSSP, PISP, HI, as well as MC, GAS, MSSA and ESBLs negative E. coli or K. pn.

Anti-Bacterial Agents↗

PubMed2004

Expression of p27 and MAPK proteins involved in all-trans retinoic acid-induced apoptosis and cell cycle arrest in matched primary and metastatic melanoma cells.

We investigated whether p27 and mitogen-activated protein kinase (MAPK) proteins were involved in all-trans retinoic acid (atRA)-induced apoptosis and cell cycle arrest. Matched primary and metastatic melanoma cells were exposed to atRA. Apoptosis and cell cycle were detected by flow cytometry. Expression of p27, Ras, B-raf, Mek and Erk proteins was examined. Results showed that atRA induced apoptosis and cell cycle arrest in both primary and metastatic melanoma cells. The primary melanoma cells were more vulnerable than their matched metastatic cells. Expression of p27 was increased, while MAPK proteins were decreased, this response was dose- and time-dependent. Alterations of these proteins were more pronounced in primary melanoma cells than in the matched metastases. These data indicate that up-regulation of p27 and down-regulation of MAPK proteins were involved in atRA-induced apoptosis and cell cycle arrest in melanoma.

Antineoplastic Agents↗

PubMed2004

Discovery and mechanism of action of a novel series of apoptosis inducers with potential vascular targeting activity.

A novel series of 2-amino-4-(3-bromo-4,5-dimethoxy-phenyl)-3-cyano-4H-chromenes was identified as apoptosis-inducing agents through our cell-based apoptosis screening assay. Several analogues from this series, MX-58151, MX-58276, MX-76747, MX-116214, MX-126303, and MX-116407, were synthesized and further characterized. MX-116407, a lead compound from this series, induced apoptosis with an EC50 of 50 nmol/L and inhibited cell growth with a GI50 of 37 nmol/L in T47D breast cancer cells. Treatment of cells with these analogues led to G2-M arrest, cleavage of essential proapoptotic caspase substrates, and induction of nuclear fragmentation. We identified these compounds as tubulin destabilizers with binding site at or close to the colchicine binding site. Compounds in this series were also active in drug-resistant cancer cell lines with a GI50 value for one of the analogues (MX-58151) of 2.5 nmol/L in paclitaxel-resistant, multidrug-resistant MES-SA/DX5 tumor cells. This series of compounds displayed high selectivity against proliferating versus resting cells. Interestingly, these compounds were shown to disrupt preformed endothelial cell capillary tubules in vitro and affect functional vasculature to induce tumor necrosis in vivo and are thus likely to work as tumor vasculature targeting agents. Among these compounds, MX-116407 showed capillary tubule disruption activity in vitro at concentrations well below the cytotoxic dose. In a separate study, we further characterized the antitumor efficacy and pharmacokinetic profile of this series of compounds and identified MX-116407 as a potent apoptosis-inducing agent with apparent activity as tumor vasculature targeting agent.

Antineoplastic Agents↗

PubMed2004

Cerebral metabolic reduction in severe malaria: fluorodeoxyglucose-positron emission tomography imaging in a primate model of severe human malaria with cerebral involvement.

Cerebral metabolic changes in Japanese macaques (Macaca fuscata) infected with Plasmodium coatneyi, a primate model of severe human malaria with cerebral involvement, were directly evaluated by fluorodeoxyglucose-positron emission tomography (FDG-PET). We observed diffuse and heterogeneous reduction of metabolism in the cerebral cortex in the acute phase of malaria infection. Neuropathologic examination showed preferential sequestration of parasitized red blood cells in the cerebral microvasculature. However, hemorrhagic change or necrosis was not observed in hematoxylin and eosin-stained and Nissl-stained brain tissues. This suggests that reduction of cerebral metabolism occurs before parenchymal changes appear in the brain. This may be one reason why more than half of the patients with cerebral malaria have no neurologic sequelae after recovery.

Animals↗

PubMed2004

[Induction of T cell responses against autologous ovarian cancer by anti-idiotype minibody-pulsed dendritic cells].

BACKGROUND & OBJECTIVE: Immunotherapy of sensitizing dendritic cells (DCs) with antigen,protein,and frozen cancer cell has been widely used in treating various cancers. The 6B11 anti-idiotype-antibody,a fusion protein prepared by our research center,can mimic ovarian cancer-associated antigen OC166-9. This study was to induce T cell cytotoxicity against autologous tumor cells of patients with ovarian cancer by 6B11 anti-idiotype-antibody. METHODS: Peripheral blood samples were collected from 10 patients with epithelial ovarian cancer,Monocytes were isolated and cultured to obtain DCs. Immature DCs were stimulated with 6B11 anti-idiotype-antibody (MINI-DC group); unpulsed DCs (unpulsed-DC group),mouse F(ab) '2 fragments pulsed DCs [F(ab)'2-DC group],and T cells alone (T group) were served as controls. Mature DCs were harvested. (3)H-thymidine ((3)H-TdR) incorporation approach was used to measure effect of DCs on stimulating auto-T cell proliferation. Cytotoxicity of DC-activated T cells against auto-tumor cells was measured with (51)Cr 6-h release test,tumor cell lines,SKOV3,HLE,and K562, were used as controls. RESULTS: In 4 cases,cpm value of (3)H-TdR incorporation,as symbol of auto-T cell proliferation, in MINI-DC group was significantly higher than those in control groups. In 5 cases,specific cytotoxicity effect of T cells on auto-tumor cells was observed in MINI-DC group at effect-target ratio of 20:1,the toxicity effect of T cells in MINI-DC group was 25%-100%,significantly higher than those in F(ab)'2-DC group (18%-40%), unpulsed-DC group (13%-43%),and T group (9%-58%). In 4 cases,the toxicity effect of T cells in MINI-DC group, at effect-target ratio of 20:1,on auto-tumor cells was 25%-100%, higher than those on SKOV3 cells (5%-51%),HLE cells (2%-38%),and K562 cells (2%-25%). Moreover,the toxicity effect of T cells in MINI-DC group on auto-tumor cells can be partially blocked by anti-MHC-I antibody,which indicated that the toxicity was antigen-specific. CONCLUSION: DCs loaded with 6B11 anti-idiotype antibody that mimic ovarian cancer antigen can induce antigen specific T cell cytotoxicity against auto-ovarian tumor cells in vitro.

Adult↗

PubMed2004

[Analysis of the intestinal infectious diseases occurring in the past ten years in a military unit].

OBJECTIVE: To identify the causes of intestinal infectious diseases in a military unit in the past 10 years. METHODS: The data of these diseases were acquired from a disease control and prevention center of a military command, including the epidemic cards, the first pages of medical record and investigation reports of the infectious diseases. Statistical analysis was performed after summarization of the data. RESULT: From 1992 to 2001, 3 612 cases of intestinal infectious diseases were reported in the military unit, most of which were bacillary dysentery (32.40%), hepatitis A (26.80%), typhoid (14.34%) and infectious diarrhea (7.34%), and 40.13% of them were intestinal infectious diseases. Fifteen epidemic outbreaks were documented from 1988 to 2002, including 9 arising from water and 6 from food contamination. CONCLUSION: Intestinal infectious diseases are seasonal and strict food and water hygiene should be maintained.

Adult↗

PubMed2004

[Clinical application of acupunctural anesthesia with new combination principle of acupoints in supratentorial craniocerebral operation of tumor in vital functional area or deep site of brain].

OBJECTIVE: To summarize the experience in applying acupunctural anesthesia (AA) with new combination principle (NCP) of acupoints in supratentorial craniocerebral operation of tumor in functional area or deep site of brain. METHODS: With the acupoints selection of AA changed from the previous combination principle of near segmental and peri-operational region to the NCP of near-remote along corresponding meridian, craniotomy was carried out under AA in 23 patients. RESULTS: Operation was performed successfully in all the patients, 82.6% of them with the effectiveness reaching I A grade. In those operated on the vital functional area, such as central anterior/posterior gyrus and language center, the accidental functional injury could be well prevented. CONCLUSION: AA with NCP of acupoints has satisfactory effect in supratentorial craniocerebral operation of functional area or deep site of brain, it is especially valuable in monitoring the effect of operation on function of around normal cerebral area to avoid accident injury.

Acupuncture Analgesia↗

PubMed2004

[The relationships between biomarkers of age-related changes in bone turnover and bone mineral density in healthy Chinese women].

OBJECTIVE: To study the relationships of serum bone alkaline phosphatase (sBAP), serum osteocalcin (sOC) and the ratio of urine cross-linked N-telopeptide of collagen type I (uNTX)/creatine (Cr) with age and bone mineral density (BMD) in healthy women aged 20 - 80 years. METHODS: sBAP, sOC and uNTX were measured using ELISA. BMD at lumbar spine 1 - 4 anteroposterior (AP) and at femoral neck (FN) was studied using DXA (QDR 4500A) in 668 healthy women. Correlations of bone biomarkers with age and BMD were fitted in entire female population by ten kinds of regression models. RESULTS: (1) sBAP, sOC and uNTX were positively correlated with age (all P < 0.001). The cubic regression model was better fitted with age-related changes of bone biomarkers as compared with the other regression models and the coefficients of determination (R(2)) of fitting curve were 0.181 - 0.381 (P < 0.001). (2) When all subjects were stratified by 10-year age groups, the bone biomarker values during 30 - 39 years of age were the lowest, then they increased gradually to a highest level in the 50 - 59 years of age. (3) When subjects were stratified by menopause, levels of sBAP, sOC and uNTX in postmenopausal women with a low value of BMD at AP and FN were significantly higher than those in premenopausal women (all P < 0.001). (4) Positive correlation among sBAP, sOC and uNTX was found (all P < 0.001) and BMD values at AP and FN were negatively correlated with all the bone biomarkers (all P < 0.001). CONCLUSIONS: sBAP, sOC and uNTX may be the sensitive and relatively specific markers to evaluate age- and menses-dependent changes of bone turnover, but they are negatively correlated with BMD, suggesting that individuals with increased bone biomarker levels are associated with a decreased BMD value.

Adult↗

PubMed2004

[Influence of mobile phase composition on chiral separation of albendazole sulfoxide racemates].

A chiral stationary phase (CSP) was prepared by coating amylose-tris(3,5-dimethylphenyl carbamate) (ADMPC) onto aminopropylated spherical silica gel. Albendazole sulfoxide (ABZSO) was directly resolved on the ADMPC-CSP by normal-phase high performance liquid chromatography (HPLC) using a series of binary and ternary mobile phases. The results indicated that the retention and stereoselectivity of ABZSO on ADMPC-CSP were significantly influenced by the kinds and the contents of the alcohols in mobile phases. The use of methanol and/or ethanol as alcoholic modifier achieved better separation of ABZSO. Effective and efficient chiral resolution was obtained by using ternary mobile phases: hexane/2-propanol/methanol or hexane/ethanol/methanol.

2-Propanol↗

PubMed2004

[Unequal interval jump grey modeling and its application to the spectral analysis of lubricating oil].

Unequal interval jump grey model was built for raw data series with unequal interval and jump trend in this paper. Levenberg-Marquardt arithmetic that belongs to non-linear least-square. estimation was used to recognize the parameters. The model built was used to fit spectrometric analysis values of diesel engine and the fitting precision is good. It is helpful to improve the accuracy and reliability of spectrometric analysis by revising test data after oil change with model parameter.

English Abstract↗

PubMed2004

[Purification efficiency of several wetland macrophytes on COD and nitrogen removal from domestic sewage].

In order to investigate the role of wetland macrophytes in waster water purification and to select appropriate native filter plants in constructed wetland, three vertical-flow constructed wetlands were built with river sands as the substrates of Acorus gramineus, Juncus effusus and Iris japonica, and one without plant as the control. Investigation on the removal of COD and total nitrogen (TN) from domestic sewage showed that within lower concentrations of COD (<200 mg x L(-1)) and TN (<30 mg x L(-1)), more than 90% of COD and 80% of TN were removed from domestic sewage in all constructed wetlands. When the concentration of COD and TN increased, the purification efficiency of all constructed wetlands decreased to some extent. The constructed wetlands with macrophytes had a higher efficiency than control. Among the three constructed wetlands with macrophytes, the one with Acorus gramineus had an average purification efficiency of 80.46% for COD and 77.77% for TN, that with Juncus effusus was 75.53% for COD and 71.17% for TN, and the one with Iris japonica was 70.50% for COD and 66.38% for TN. The constructed wetland without vegetation had an average purification efficiency of 61.39% for COD and 55.81% for TN. Acorus gramineus was more capable of removing COD and TN than Juncus effusus and Iris japonica. Vegetation biomass was the main factor affecting the removal rate of COD and nitrogen, because it significantly correlated with the ability of absorbing organic substance and nitrogen, and with the nitrification and denitrification around roots.

Acorus↗

PubMed2004

[Studies on the chemical constituents of the essential oil from the leaves of Dalbergia odorifera T. Chen].

OBJECTIVE: To study the constituents of the essential oil from the leaves of Dalbergia odorifera T. Chen. METHOD: The constituent were separated and identified by GS-MS. RESULT: 21 compounds from the essential oil were identifed, which account for 77.71% of total volatile oils, 21.73% of 2-methoxy-4-vinylphenol, 13.97% of n-hexadecanoic acid, 6.69% of phenol. CONCLUSION: The study provided a chemical basis as a medicinal herb.

Dalbergia↗

PubMed2004

[Oral motor dysfunction, feeding problems and nutritional status in children with cerebral palsy].

OBJECTIVE: This study was undertaken to investigate the clinical features of oral motor dysfunction and feeding problems as well as the nutritional status of children with cerebral palsy (CP). METHODS: Fifty-nine CP children, 39 boys and 20 girls, mean age 31 months (20 to 72 months), were recruited. Their parents were interviewed for high risk factors and feeding history. Each case was assessed for oral motor and feeding problems based on oral motor and feeding skill score; for nutritional status by measurement of weight, height; neurologically for type of cerebral palsy and for developmental age by Gesell's developmental scale. Equal number of age and sex matched controls were included for comparison of nutritional status, oral motor and feeding skill score. RESULTS: Among 59 patients, 51 cases had oral motor dysfunction and 55 cases had feeding problems including all athtosis, spastic tetraplegia, and 16 had spastic diplegia. The scores of both the mean oral motor function and feeding skill of CP children were significantly lower than those of the controls (P < 0.001). Main food of children with cerebral palsy consisted of liquid and semisolid diet. Body weight and height below the 25th percentile were found in 13 cases and 19 cases, respectively. CONCLUSIONS: The majority of the children with cerebral palsy had oral motor dysfunction and feeding problems which appeared in early age and disturbed the growth and nutritional status. Thorough assessment for oral motor function, feeding problems and nutritional status of CP children is indicated in order to start timely rehabilitation and nutritional interventions which can significantly improve their nutritional status and quality of life.

Cerebral Palsy↗

PubMed2004

Expression of TIMP-3 gene by construction of a eukaryotic cell expression vector and its role in reduction of metastasis in a human breast cancer cell line.

The present study is aimed at studying the gene for TIMP-3, a mammalian tissue inhibitor, by constructing a recombinant eukaryotic cell vector for gene therapy in human breast cancer. We obtained the TIMP-3 gene from the human placent by RT-PCR. TIMP-3 gene was subcloned into pcDNA3.1 vetor from pMD18T vector by means of gene cloning to construct pcDNA3.1 recombinant vector. Human breast cancer cell line MDA-MB-453 was transfected with pcDNA3.1-TIMP3 recombinant vector using lipofectamine reagent. Then the expression of TIMP-3 and the effect on the metastasis of MDA-MB-453 were examined. The correct construction of pcDNA-TIMP3 was identified by means of restriction enzyme analysis, PCR amplication and nucleotide sequencing. Western blotting showed that the transfected cells were able to express TIMP-3, indicating that our construction of the pcDNA-TIMP3 eukaryotic expression vector was constructed successfully. Our experiments further indicated that the potential of metastasis was significantly reduced for the transfected cell line MDA-MB-453.

Breast Neoplasms↗

PubMed2003

The thrH gene product of Pseudomonas aeruginosa is a dual activity enzyme with a novel phosphoserine:homoserine phosphotransferase activity.

The thrH gene product of Pseudomonas aeruginosa has been shown to complement both homoserine kinase (thrB gene product) and phosphoserine phosphatase (serB gene product) activities in vivo. Sequence comparison has revealed that ThrH is related to phosphoserine phosphatases (PSP, EC 3.1.3.3) and belongs to the l-2-haloacid dehalogenase-like protein superfamily. We have solved the crystal structures of ThrH in the apoform and in complex with a bound product phosphate. The structure confirms an overall fold similar to that of PSP. Most of the catalytic residues of PSP are also conserved in ThrH, suggesting that similar catalytic mechanisms are used by both enzymes. Spectrophotometry-based in vitro assays show that ThrH is indeed a phosphoserine phosphatase with a K(m) of 0.207 mm and k(cat) of 13.4 min(-1), comparable with those of other PSPs. More interestingly, using high pressure liquid chromatography-based assays, we have demonstrated that ThrH is able to further transfer the phosphoryl group to homoserine using phosphoserine as the phosphoryl group donor, indicating that ThrH has a novel phosphoserine:homoserine phosphotransferase activity.

Amino Acid Sequence↗

PubMed2003

GATA-4 regulates cardiac morphogenesis through transactivation of the N-cadherin gene.

Cardia bifida is known to occur in animal models lacking the cardiogenic transcriptional factor GATA-4. The downstream target genes responsible for this cardiac deformity remain unknown, however. Treatment with small interfering RNAs (siRNA) specifically targeting GATA-4 into cardiac mesodermal cells led to the development of cardia bifida in chick embryos. RT-PCR using mRNAs extracted from cardiac tubes revealed that the GATA-4-specific siRNA selectively suppresses expression of N-cadherin mRNA, one of the genes essential for the single heart formation, without affecting other cardiac marker mRNAs. Analysis of the N-cadherin gene promoter activity using a luciferase reporter gene system and electrophoretic mobility shift assays revealed that GATA-4 binds directly to the N-cadherin gene promoter region, thereby transactivating its expression. We therefore concluded that the cardia bifida observed in the GATA-4-deleted model is caused by the transcriptional down-regulation of N-cadherin expression.

Animals↗

PubMed2003

A novel cleavage product formed by autoxidation of lycopene induces apoptosis in HL-60 cells.

Dietary carotenoids have been thought to have beneficial effects on human health through their antioxidant activity, provitamin A activity, and effects on cancer cell propagation. Recent studies suggest that oxidation products or metabolites are involved in biological activities of carotenoids. We previously reported that an autoxidation mixture of lycopene induced apoptosis in HL-60 human promyelocytic leukemia cells, but lycopene alone did not. In the present study, bioassay-directed fractionations of autoxidized lycopene led to isolation of a novel cleavage product of lycopene. Spectral analyses elucidated its structure as (E,E,E)-4-methyl-8-oxo-2,4,6-nonatrienal (MON), suggesting the formation through the oxidative cleavages at the 5, 6- and 13, 14-double bonds of lycopene. MON was proved to cause a dose-dependent reduction of viability in HL-60 cells with morphological changes such as chromatin condensation and nuclear fragmentation. Treatment of HL-60 cells with MON could induce DNA fragmentation and increase apoptotic cells in a time- and dose-dependent manner. The MON treatment could enhance both caspase 8 and caspase 9 activities. Moreover, it reduced the expression of Bcl-2 and Bcl-XL proteins, whereas it had no effect on the level of Bax protein. These results clearly indicated that MON induced apoptosis in HL-60 cells, associated with the down regulation of Bcl-2 and Bcl-XL and the activation of caspase cascades. The concentration of MON attained by treatment of the autoxidized lycopene preparation was far less than the IC50 (10 microM) value of MON alone in reducing the viability of HL-60 cells. The fractionation of the oxidized lycopene indicated the presence of other active oxidation products. Thus, unidentified products as well as MON would be responsible for the apoptosis-inducing activity of the autoxidized lycopene.

Apoptosis↗

PubMed2003

Isolation of DNA-free RNA, DNA, and proteins by cesium trifluoroacetate centrifugation.

The ability to simultaneously isolate intact DNA-free RNA, genomic DNA, and proteins from a biological specimen can be useful in cloning genes and analyzing gene expression. Equilibrium density gradient centrifugation with CsCl is a useful tool for fractionating, quantitatively separating, and characterizing RNA, DNA, and the total quota of proteins, respectively, based on differences in their buoyant densities. In the present study we have reexamined the rarely used cesium salt, cesium trifluoroacetate, for the same purpose. A significant advantage of CsTFA lies in the fact that, unlike in CsCl, RNA can be recovered from a single, soluble fraction of the CsTFA gradient. Furthermore, unlike CsCl, CsTFA is freely soluble in ethanol so that co-precipitation of the salt in the recovered RNA upon alcohol precipitation does not take place. Hence, the RNA is recovered with minimum manipulations. The one-step separation of cellular macromolecule classes free of each other in small amount of starting materials provides a major advantage over other methods currently in use.

Cell Line↗