An integrated simulation and optimization approach for managing human health risks of atmospheric pollutants by coal-fired power plants

This research developed a simulation-aided nonlinear programming model (SNPM). This model incorporated the consideration of pollutant dispersion modeling, and the management of coal blending and the related human health risks within a general modeling framework In SNPM, the simulation effort (i.e., California puff [CALPUFF]) was used to forecast the fate of air pollutants for quantifying the health risk under various conditions, while the optimization studies were to identify the optimal coal blending strategies from a number of alternatives. To solve the model, a surrogate-based indirect search approach was proposed, where the support vector regression (SVR) was used to create a set of easy-to-use and rapid-response surrogates for identifying the function relationships between coal-blending operating conditions and health risks. Through replacing the CALPUFF and the corresponding hazard quotient equation with the surrogates, the computation efficiency could be improved. The developed SNPM was applied to minimize the human health risk associated with air pollutants discharged from Gaojing and Shijingshan power plants in the west of Beijing. Solution results indicated that it could be used for reducing the health risk of the public in the vicinity of the two power plants, identifying desired coal blending strategies for decision makers, and considering a proper balance between coal purchase cost and human health risk.

IMPLICATIONS

A simulation-aided nonlinear programming model (SNPM) is developed. It integrates the advantages of CALPUFF and nonlinear programming model. To solve the model, a surrogate-based indirect search approach based on the combination of support vector regression and genetic algorithm is proposed. SNPM is applied to reduce the health risk caused by air pollutants discharged from Gaojing and Shijingshan power plants in the west of Beijing. Solution results indicate that it is useful for generating coal blending schemes, reducing the health risk of the public, reflecting the trade-offbetween coal purchase cost and health risk.

Antitumor efficacy of DMSA modified Fe3O4 magnetic nanoparticles combined with arsenic trioxide and adriamycin in Raji cells

The objective of the present study was to investigate the anticancer efficacy of dimercaptosuccinic acid modified iron oxide (DMSA-Fe3O4) magnetic nanoparticles (MNPs) combined with arsenic trioxide (As2O3) and doxorubicin (ADM) in non-Hodgkin's lymphoma (NHL) cell line (Raji cells). The growth inhibition rate of Raji cells was determined by MTT assay. Characteristics of DMSA-Fe3O4 MNPs and distribution of nanoparticles taken up by Raji cells were observed under a transmission electron microscopy (TEM). Further, apoptosis of cells and intracellular concentration of ADM were detected by flow cytometry (FCM). DAPI staining was used to view apoptotic cellular morphology. Subsequently, transcription and protein expression levels of bcl-2, NFKB, survivin, bax, p53 and caspase-3 were determined by reverse transciptase polymerase chain reaction (RT-PCR) and Western blotting analysis, respectively. The results of MTT assay indicated that the inhibition of Raji cells by the combined form of ADM and As2O3 was significantly higher than either ADM or As2O3 alone. However, ADM-As2O3 MNPs proved superior over all other groups. TEM observation revealed that the majority of MNPs were quasi-spherical with an average diameter of about 18 nm and the MNPs taken up by cells were located in the endosome vesicles of cytoplasm. The apoptotic rate and accumulation of intracellular ADM in ADM-As2O3 MNPs group were significantly higher than those in control, ADM, As2O3 and ADM+As2O3, groups. In addition, DAPI staining of Raji cells from ADM-As,O3 MNPs group clearly exhibited more morphological changes (severe structural alterations) than other groups. Moreover, transcription and protein expression of bcl-2, NFKB, survivin, bax, p53 and caspase-3 of Raji cells were regulated at the most remarkable extent in ADM-As2O3, MNPs group as compared with other groups. These findings suggest that the antitumor efficacy of the combination of novel ADM-As2O3, MNPs on Raji cells would be a promising strategy for lymphoma therapy.

Cytotoxic effects of mono-(2-ethylhexyl) phthalate on human embryonic stem cells

BACKGROUND

Mono-(2-ethylhexyl) phthalate (MEHP), the metabolite of di-(2-ethylhexyl) phthalate (DEHP), was suspected to be toxic to human embryos. This study contributes to investigating its toxic effects by an embryonic stem cell test (EST) based on two human embryonic stem cell (hESCs) lines.

METHODS

CH1 established in our own lab and H1, a federally registered cell line were two human embryonic stem cell lines used in this test. Four endpoint measurements were performed consisting of cell viability, proliferation ability, apoptosis as well as changes of gene expression patterns after spontaneous differentiation were determined. For measuring effects on the first three endpoints, the cells were treated with various concentrations of MEHP dissolved in dimethyl sulfoxide (DMSO) and only with DMSO which served as control and harvested after 5 days. For measuring effects during spontaneous differentiation, the RNA of embryoid bodies (EBs) formed after 8 days' MEHP exposure was collected and changes in differentiation specific gene expression patterns were analyzed by quantitative real time RT-PCR.

RESULTS

As a result the viability and proliferation ability of both cell lines decreased significantly at 1000 µmol/L MEHP, while there was no effect on apoptosis or cell morphology. In addition MEHP also changed the gene expression pattern in the EBs of both cell lines.

CONCLUSION

MEHP in a high dose was cytotoxic and affected the development of hESCs, which indicates its embryo toxicity in human embryos.

Up-regulation of tissue inhibitor of metalloproteinase-2 promotes SHI-1 cell invasion in nude mice

The role of tissue inhibitor of metalloproteinase-2 (TIMP-2) in extramedullary infiltration of acute leukemia is unclear. We demonstrated in our previous study that the up-regulation of TIMP-2 promoted SHI-1 cell invasion in vitro. We investigated in the present study whether TIMP-2 would have the same effect in vivo. A retroviral vector carrying human TIMP-2 cDNA was constructed and transfected into SHI-1 cells. Three subclone cells (S1, S2 and S3) that highly expressed TIMP-2 were selected to establish nude mouse models of acute leukemia. Times of leukemic onset in mice of S1, S2 and S3 groups were all earlier than that of the SHI-1 group, whereas the survival times of S1, S2 and S3 groups were all shorter than that of the SHI-1 group (p < 0.05). Histopathological results demonstrated severe leukemic infiltration in numerous organs in each group. Reverse transcription polymerase chain reaction (RT-PCR) assay showed that several organs expressed the MLL/F6 fusion gene. Moreover, the numbers of organs infiltrated by leukemic cells in S1, S2 and S3 groups were more than those in the SHI-1 group (p < 0.05). Up-regulating TIMP-2 expression enhanced SHI-1 cell invasion in nude mice and resulted in more severe leukemia infiltration. This phenomenon suggests that targeted therapy with TIMP-2 for acute leukemia should be performed with prudence.

[Vasculogenic mimicry in tongue squamous cell carcinoma]

OBJECTIVE

To investigate the presence of vasculogenic mimicry (VM) in tongue squamous cell carcinoma and explore its clinical significance.

METHODS

Forty-two surgical specimens of tongue squamous cell carcinoma were examined for the presence of VM using HE staining and double staining of CD34 and PAS.

RESULTS

Of the 42 specimens, 18 (42.86%) showed the presence of VM. VM was not correlated with the patients' age or gender, but with lymph node metastasis and the grade of tumor differentiation. Compared with tumors without VM, the tumors with VM had a significantly higher rate of lymph node metastasis (P<0.05) and a lower grade of differentiation (P<0.05).

CONCLUSION

VM can be present in tongue squamous cell carcinoma, and the poorly differentiated tumors contain more VM, which is associated with a greater likeliness of lymph node metastasis and a poorer prognosis.

ChIPModule: systematic discovery of transcription factors and their cofactors from ChIP-seq data

We have developed a novel approach called ChIPModule to systematically discover transcription factors and their cofactors from ChIP-seq data. Given a ChIP-seq dataset and the binding patterns of a large number of transcription factors, ChIPModule can efficiently identify groups of transcription factors, whose binding sites significantly co-occur in the ChIP-seq peak regions. By testing ChIPModule on simulated data and experimental data, we have shown that ChIPModule identifies known cofactors of transcription factors, and predicts new cofactors that are supported by literature. ChIPModule provides a useful tool for studying gene transcriptional regulation.

Synergistic effect of a combination of nanoparticulate Fe3O4 and gambogic acid on phosphatidylinositol 3-kinase/Akt/Bad pathway of LOVO cells

Background:

The present study evaluated whether magnetic nanoparticles containing Fe₃O₄ could enhance the activity of gambogic acid in human colon cancer cells, and explored the potential mechanisms involved.

Methods:

Cytotoxicity was evaluated by MTT assay. The percentage of cells undergoing apoptosis was analyzed by flow cytometry, and cell morphology was observed under both an optical microscope and a fluorescence microscope. Reverse transcriptase polymerase chain reaction and Western blot assay were performed to determine the transcription of genes and expression of proteins, respectively.

Results:

Gambogic acid could inhibit proliferation of LOVO cells in a dose-dependent and time-dependent manner and induce apoptosis, which was dramatically enhanced by magnetic nanoparticles containing Fe₃O₄. The typical morphological features of apoptosis in LOVO cells were observed after treatment comprising gambogic acid with and without magnetic nanoparticles containing Fe₃O₄. Transcription of cytochrome c, caspase 9, and caspase 3 genes was higher in the group treated with magnetic nanoparticles containing Fe₃O₄ and gambogic acid than in the groups that received gambogic acid or magnetic nanoparticles containing Fe₃O₄, but transcription of phosphatidylinositol 3-kinase, Akt, and Bad genes decreased. Notably, expression of cytochrome c, caspase 9, and caspase 3 proteins in the group treated with gambogic acid and magnetic nanoparticles containing Fe₃O₄ was higher than in the groups receiving magnetic nanoparticles containing Fe₃O₄ or gambogic acid, while expression of p-PI3K, p-Akt, p-Bad, pro-caspase 9, and pro-caspase 3 degraded.

Conclusion:

Magnetic nanoparticles containing Fe₃O₄ can enhance apoptosis induced by gambogic acid which may be closely related to regulation of the PI3K/Akt/Bad pathway in the treatment of human colon cancer.

Pathogenicity and distribution of highly pathogenic porcine reproductive and respiratory syndrome virus in pigs

The pathogenesis of highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) strain (HuN4) is poorly understood. Therefore, highly pathogenic PRRSV strain (HuN4) and its derivative strain (HuN4-F112) (obtained by propagation in MARC145 cells for 112 passages) were inoculated into a total of 48 PRRSV-sero-negative pigs (age: 4-5 weeks) by the intranasal route. Virological, pathological and in situ hybridization analyses were performed. The results exhibited that pigs infected with HuN4 showed a loss of appetite, decrease in body weight, raised body temperature and respiratory symptoms, along with interstitial pneumonia lesions. In the HuN4 group, multifocal interstitial pneumonia with macrophage infiltration was found in the lung. The lesions in the lymph node were characterized by collapsed follicles, depletion of germinal centres and reduction in lymphocytes. Perivascular cuffing and glial nodules were observed in the brains of some pigs. By comparison, the HuN4-F112 group had milder lesions. PRRSV was detected in macrophages, alveolar epithelial cells and vascular endothelial cells in the tonsil and lymph nodes. The PRRSV amounts in the pigs infected with HuN4 were 10(5) -10(9) copies/ml in the blood and 10(10) -10(11) copies/g in the lung tissues, whereas the virus amounts with HuN4-F112 were 10(2.15) -10(3.13) copies/ml in the blood and 10(3.0) -10(3.6) copies/g in the lung. Our results demonstrate that the PRRS HuN4 virus infects alveolar epithelial cells, macrophages and vascular endothelial cells causing diffuse alveolar damage and lymph node necrosis. Its higher pathogenicity compared with HuN4-F112 virus may be explained in part by higher replication rate in the previously mentioned organs.

[NKG2D-mediated natural killer cell cytotoxicity against myeloid leukemia cells OUN-1]

OBJECTIVE

To investigate NK cell cytotoxicity to leukemic cell by NKG2D receptors and NKG2D ligands interaction upregulated by hydroxyurea (HU).

METHODS

Leukemic cell lines OUN-1 and primary leukemic cells were cultured for 24 hours in the presence of HU, then the NKG2D ligands expressions were analyzed by flow cytometry (FCM). Isolated NK cells from healthy individual cultured for 72 hours in presence of IL-2 were used as effect cell, and leukemic cell line OUN-1 treated with HU was used as target cell, NK cell cytotoxicity against leukemic cell line was assessed using chromium-51 release assay.

RESULTS

Leukemic cell lines showed upregulation of MIC A/B (MFI: 8.9 ± 0.9 vs 23.5 ± 3.4, P = 0.01) and ULBP2 (MFI: 14.5 ± 0.6 vs 33.5 ± 4.8, P = 0.03) following incubation with HU. HU also upregulated the NKG2DLs on primary leukemia cells from patients with acute myeloid leukemia. Treatment of OUN-1 with HU significantly increased the cytotoxicity of NK cells isolated from healthy individual \[(62.0 ± 5.6)% vs (76.0 ± 5.3)%, P = 0.02\], and the enhancing effect of HU was partly blocked by anti-NKG2D Abs \[(76.0 ± 5.3)% vs (46.0 ± 4.5)%, P = 0.00\].

CONCLUSION

HU selectively upregulated NKG2D ligand expression on leukemic cell lines, and enhanced NK cell cytotoxicity against leukemic cells through NKG2D receptors and NKG2D ligands interaction.

Multifunctional magnetic Fe3O4 nanoparticles combined with chemotherapy and hyperthermia to overcome multidrug resistance

BACKGROUND

Multidrug resistance in cancer is a major obstacle for clinical therapeutics, and is the reason for 90% of treatment failures. This study investigated the efficiency of novel multifunctional Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)-MNP) combined with chemotherapy and hyperthermia for overcoming multidrug resistance in an in vivo model of leukemia.

METHODS

Nude mice with tumor xenografts were randomly divided into a control group, and the treatment groups were allocated to receive daunorubicin, 5-bromotetrandrine (5-BrTet) and daunorubicin, Fe(3)O(4)-MNP, and Fe(3)O(4)-MNP coloaded with daunorubicin and 5-bromotetrandrine (Fe(3)O(4)-MNP-DNR-5-BrTet), with hyperthermia in an alternating magnetic field. We investigated tumor volume and pathology, as well as P-glycoprotein, Bcl-2, Bax, and caspase-3 protein expression to elucidate the effect of multimodal treatment on overcoming multidrug resistance.

RESULTS

Fe(3)O(4)-MNP played a role in increasing tumor temperature during hyperthermia. Tumors became significantly smaller, and apoptosis of cells was observed in both the Fe(3)O(4)-MNP and Fe(3)O(4)-MNP-DNR-5-BrTet groups, especially in the Fe(3)O(4)-MNP-DNR-5-BrTet group, while tumor volumes in the other groups had increased after treatment for 12 days. Furthermore, Fe(3)O(4)-MNP-DNR-5-BrTet with hyperthermia noticeably decreased P-glycoprotein and Bcl-2 expression, and markedly increased Bax and caspase-3 expression.

CONCLUSION

Fe(3)O(4)-MNP-DNR-5-BrTet with hyperthermia may be a potential approach for reversal of multidrug resistance in the treatment of leukemia.

Effect of magnetic nanoparticles on apoptosis and cell cycle induced by wogonin in Raji cells

Traditional Chinese medicine is gradually becoming a new source of anticancer drugs. One such example is wogonin, which is cytotoxic to various cancer cell lines in vitro. However, due to its low water solubility, wogonin is restricted to clinical administration. Recently, the application of drug-coated magnetic nanoparticles (MNPs) to increase water solubility of the drug and to enhance its chemotherapeutic efficiency has attracted much attention. In this study, wogonin was conjugated with the drug delivery system of MNPs by mechanical absorption polymerization to fabricate wogonin-loaded MNPs. It was demonstrated that MNPs could strengthen wogonin-induced cell inhibition, apoptosis, and cell cycle arrest in Raji cells by methylthiazol tetrazolium assay, flow cytometer assay, and nuclear 4′,6-diamidino-2-phenylindole staining. Furthermore, the molecular mechanisms of these phenomena were explored by western blot, in which the protein levels of caspase 8 and caspase 3 were increased significantly while those of survivin and cyclin E were decreased significantly in wogonin-MNPs group. These findings suggest that the combination of wogonin and MNPs provides a promising strategy for lymphoma therapy.

FFAS server: novel features and applications

The Fold and Function Assignment System (FFAS) server [Jaroszewski et al. (2005) FFAS03: a server for profile–profile sequence alignments. Nucleic Acids Research, 33, W284–W288] implements the algorithm for protein profile–profile alignment introduced originally in [Rychlewski et al. (2000) Comparison of sequence profiles. Strategies for structural predictions using sequence information. Protein Science: a Publication of the Protein Society, 9, 232–241]. Here, we present updates, changes and novel functionality added to the server since 2005 and discuss its new applications. The sequence database used to calculate sequence profiles was enriched by adding sets of publicly available metagenomic sequences. The profile of a user’s protein can now be compared with ∼20 additional profile databases, including several complete proteomes, human proteins involved in genetic diseases and a database of microbial virulence factors. A newly developed interface uses a system of tabs, allowing the user to navigate multiple results pages, and also includes novel functionality, such as a dotplot graph viewer, modeling tools, an improved 3D alignment viewer and links to the database of structural similarities. The FFAS server was also optimized for speed: running times were reduced by an order of magnitude. The FFAS server, http://ffas.godziklab.org, has no log-in requirement, albeit there is an option to register and store results in individual, password-protected directories. Source code and Linux executables for the FFAS program are available for download from the FFAS server.

A promising strategy for overcoming MDR in tumor by magnetic iron oxide nanoparticles co-loaded with daunorubicin and 5-bromotetrandrin

To overcome both the dose-limiting side effects of conventional chemotherapeutic agents and the therapeutic failure resulting from multidrug resistance (MDR) and minimize adverse effects of chemotherapy agents, a novel chemotherapy formulation of magnetic nanoparticles co-loaded with daunorubicin and 5-bromotetrandrin (DNR/BrTet-MNPs) was developed, and its effect on MDR leukemic cells was explored. After the DNR and Br were co-loaded onto a pluronic-stabilized and oleic acid-modified magnetic nanosystem, the physical characteristic and drug-loading capacity were evaluated. The cell toxicity of the self-prepared DNR/BrTet-MNPs formulation was then determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay; the cellular uptake of drug was demonstrated by fluorescent microscope. Lastly, the transcription of mdr1 and the expression of P-glycoprotein (P-gp) were detected by the reverse transcription reaction and western blotting assay, respectively. The results showed that the self-prepared DNR/BrTet-MNPs formulation possessed a sustained release of drug and displayed a dose-dependent antiproliferative activity on MDR leukemia K562/A02 cells. It also enhanced the accumulation of intracellular DNR in K562/A02 cells and downregulated the transcription of the mdr1 gene and the expression of P-gp. These findings suggest that the remarkable effect of the novel DNR/BrTet-MNPs formulation, acting as a drug depot system for the sustained release of the loaded DNR and BrTet, on multidrug resistance leukemia K562/A02 cells would be a promising strategy for overcoming MDR.

Apoptotic mechanism of human leukemia K562/A02 cells induced by magnetic iron oxide nanoparticles co-loaded with daunorubicin and 5-bromotetrandrin

The purpose of this study was to assess the induced apoptosis of self-assembled iron oxide magnetic nanoparticles (MNPs) co-loaded with daunorubicin (DNR) and 5-bromotetrandrin (Br Tet) (DNR/Br Tet-MNPs), acting as a drug depot system for the sustained release of the loaded DNR and BrTet, in the drug resistant human leukemia K562/A02 cells and further to explore potential mechanisms. After being incubated for 48 hours, K562/A02 cells were treated with DNR/Br Tet-MNPs or DNR and Br Tet in solution (DNR/Br Tet-Sol). Morphologic characteristics of K562/A02 cells were observed under a fluorescence microscope; cell apoptosis and intracellular accumulation of DNR were analyzed by FACS Calibur flow cytometry. Furthermore, reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting analyses were performed to study the apoptosis associated gene transcription and protein expression, respectively. Typical apoptotic characteristics, including chromatin condensation and fragmentation of nuclei, were observed and a high rate of apoptosis was detected in K562/A02 cells treated with DNR/Br Tet-MNPs and DNR/Br Tet-Sol. Detection of relative fluorescence intensity of intracellular DNR demonstrated that intracellular DNR was higher in K562/A02 cells treated with DNR/Br Tet-MNPs than that of DNR/Br Tet-Sol. Further study demonstrated that both DNR/Br Tet-MNPs and DNR/Br Tet-Sol reduced the gene transcriptions and protein expressions of bcl-2 and survivin and enhanced that of bax and caspase 3. It is concluded that self-assembled DNR/Br Tet-MNPs, as one of the potential antitumor agents for hematologic malignancies, may effectively induce apoptosis of K562/A02 cells through elevating the ratio of bax/bcl-2, activating caspase 3, and inactivating survivin.

The changes of T lymphocytes and cytokines in ICR mice fed with Fe3O4 magnetic nanoparticles

The aim of this article is to study the changes inhibited T lymphocytes and cytokines related to the cellular immunity in ICR (imprinting control region) mice fed with Fe₃O₄ magnetic nanoparticles (Fe₃O₄-MNPs). The Fe₃O₄-MNPs were synthesized, and their characteristics such as particle size, zeta potential, and X-ray diffraction patterns were measured and determined. All ICR mice were sacrificed after being exposed to 0, 300, 600, and 1200 mg/kg of Fe₃O₄-MNPs by single gastric administration for 14 days. Splenocytes proliferation was indicated with stimulate index by MTT assay; release of cytokines in the serum of ICR mice was detected by enzyme-linked immunosorbent assay, and the phenotypic analyses of T-lymphocyte subsets were performed using flow cytometry. Our results indicated that there were no significant differences in splenocyte proliferation and release of cytokines between exposed and control groups. Furthermore, there was no significant difference in the proportions of T-lymphocyte subsets in the low-dose Fe₃O₄-MNPs group when compared to the control group, but the proportions of CD3⁺CD4⁺ and CD3⁺CD8⁺ T-lymphocyte subsets both in the medium- and high-dose Fe₃O₄-MNPs groups were higher than those in the control group. It is concluded that a high dose of Fe₃O₄-MNPs, to some extent, could influence in vivo immune function of normal ICR mice.

TIR domain-containing adaptor SARM is a late addition to the ongoing microbe-host dialog

Toll/interleukin-1 receptor (TIR) domain-containing proteins play important roles in defense against pathogens in both animals and plants, connecting the immunity signaling pathways via a chain of specific protein-protein interactions. Among them is SARM, the only TIR domain-containing adaptor that can negatively regulate TLR signaling. By extensive phylogenetic analysis, we show here that SARM is closely related to bacterial proteins with TIR domains, suggesting that this family has a different evolutionary history from other animal TIR-containing adaptors, possibly emerging via a lateral gene transfer from bacteria to animals. We also show evidence of several similar, independent transfer events, none of which, however, survived in vertebrates. An evolutionary relationship between the animal SARM adaptor and bacterial proteins with TIR domains illustrates the possible role that bacterial TIR-containing proteins play in regulating eukaryotic immune responses and how this mechanism was possibly adapted by the eukaryotes themselves.

The crystal structure of a bacterial Sufu-like protein defines a novel group of bacterial proteins that are similar to the N-terminal domain of human Sufu

Sufu (Suppressor of Fused), a two-domain protein, plays a critical role in regulating Hedgehog signaling and is conserved from flies to humans. A few bacterial Sufu-like proteins have previously been identified based on sequence similarity to the N-terminal domain of eukaryotic Sufu proteins, but none have been structurally or biochemically characterized and their function in bacteria is unknown. We have determined the crystal structure of a more distantly related Sufu-like homolog, NGO1391 from Neisseria gonorrhoeae, at 1.4 Å resolution, which provides the first biophysical characterization of a bacterial Sufu-like protein. The structure revealed a striking similarity to the N-terminal domain of human Sufu (r.m.s.d. of 2.6 Å over 93% of the NGO1391 protein), despite an extremely low sequence identity of ∼15%. Subsequent sequence analysis revealed that NGO1391 defines a new subset of smaller, Sufu-like proteins that are present in ∼200 bacterial species and has resulted in expansion of the SUFU (PF05076) family in Pfam.

Synthesis and antitumor efficacy of daunorubicin-loaded magnetic nanoparticles

Background

A promising approach to optimize the disposition of daunorubicin-loaded magnetic nanoparticles (DNR-MNPs) was developed to minimize serious side effects of systematic chemotherapy for cancer.

Methods

The physical properties of DNR-MNPs were investigated and their effect on leukemia cells in vitro was evaluated by a standard WST-1 cell proliferation assay. Furthermore, cell apoptosis and intracellular accumulation of DNR were determined by FACSCalibur flow cytometry.

Results

Our results showed that the majority of MNPs were spherical and their sizes were from 10 to 20 nm. The average hydrodynamic diameter of DNR-MNPs in water was 94 nm. The in vitro release data showed that the DNR-MNPs have excellent sustained release property. Proliferation of K562 cells was inhibited in a dose-dependent manner by DNR in solution (DNR-Sol) or by DNR-MNPs. The IC₅₀ for DNR-MNPs was slightly higher than that for DNR-Sol. DNR-MNPs also induced less apoptosis in K562 cells than did DNR-Sol. Detection of fluorescence intensity of intracellular DNR demonstrated that DNR-MNPs could be taken up by K562 cells and persistently released DNR in cells.

Conclusion

Our study suggests that optimized DNR-MNPs formulation possesses sustained drug-release and favorable antitumor properties, which may be used as a conventional dosage form for antitumor therapy.

[Distribution and antibiotic resistance of pathogen isolated from mid-stream urine of 658 patients]

OBJECTIVE

To investigate the bacterial distribution and resistance to antibiotics in culture-positive urine, and to provide reference for rational use of antibiotics in clinical practice.

METHODS

Distribution and antibiotic resistance to pathogens in 658 culture-positive patients from Jan. 1, 2007 to Dec. 31, 2008 were analyzed.

RESULTS

(1)Pathogenic strains from the 658 patients were collected from the urine specimen in the survey, which included Gram-negative bacilli (70.82%), Gram-positive cocci (26.14%) and fungi (3.04%). The distribution rate of Escherichia coli declined from 68.91% in 2008 to 63.43% in 2007 (P>0.05), and Enterococcus rose from 3.37% to 7.67% (P>0.05), but the difference was not significant. The proportion of Gram-negative bacilli (especially the E.coli) from patients in the Emergency Department and Out-patient Department was higher than that from in-patients, and the proportion of K. pneumonia and Gram-positive bacteria was lower than in-patients, both with significant differences (P<0.05). (2) The resistance rate of E. coli and K. pneumonia to quinolones was 28.57%-56.25%, and the resistance rate to 3rd generation cephalosporin was 38.78%-65.78%, respectively. The resistance rate of Gram-positive cocci to quinolones and 3rd generation cephalosporin was both higher than 50%, and was 11.05% to Vancomycin.

CONCLUSION

Gram-negative bacilli such as E. coli and K. pneumonia are predominant organism in the urinary tract infections, but proportion of Gram-positive bacteria has increased in recent years. Attention needs to be paid to the overall and severe bacterial resistance in the urinary tract infections and rational use of antibiotics.