Design, synthesis and antitumor activity of a novel PEG-A6-conjugated irinotecan derivative.

A novel PEG-A6-conjugated irinotecan derivative 8 was designed and synthesized as antitumor agent by the PEGylation and A6-peptide modification of irinotecan. In vivo antitumor activity screening assay revealed that 8 exhibited better in vivo antiproliferation activity than irinotecan and its previous PEG-cRGD-conjugated derivative BGC0222 in MIA PaCa-2, NCI-H446, MDA-MB-231, HT-29 and NCI-N87 xenograft models, while the tumor of one in six mice in NCI-H446 assay and the tumors of two in six mice in MIA PaCa-2 assay completely subsided and disappeared within the 21-day period of 8-treatment, indicating that 8 should be a potential antitumor agent.

The Raf-1 inhibitor GW5074 and the ERK1/2 pathway inhibitor U0126 ameliorate PC12 cells apoptosis induced by 6-hydroxydopamine.

6-Hydroxydopamine (6-OHDA) is a widely used dopaminergic neurotoxin that leads to cell apoptosis in vivo and in vitro, and is a widely accepted experimental model of neurodegeneration in Parkinson's disease. However, the molecular mechanisms responsible for 6-OHDA-induced cell apoptosis are unclear. We found that the treatment of PC12 cells with 6-OHDA resulted in a significant decrease in cell viability and elevated apoptosis as detected by MTT assay, Hoechst 33258 staining, and flow cytometry. In addition, 6-OHDA induced a time-dependent phosphorylation of ERK1/2 at Thr-202/Tyr-204 and of Raf-1 at Ser-338, but a decreased level of Raf-1 phosphorylation at Ser-259. Phosphorylation of ERK1/2 at Thr-202/Tyr-204 and Raf-1 at Ser-338 were inhibited by the Raf-1 inhibitor GW5074, while the ERK1/2 pathway inhibitor U0126 decreased phosphorylation of ERK1/2. Furthermore, 6-OHDA-induced PC12 cells apoptosis was suppressed by GW5074 and U0126. Our results suggest that GW5074 and U0126 act as neuroprotants against 6-OHDA toxicity in PC12 cells by modulating Raf-1/ERK1/2 signaling systems.

DDAH2 (-449 G/C) G allele is positively associated with leukoaraiosis in northeastern China: a double-blind, intergroup comparison, case-control study.

Cerebrovascular endothelial dysfunction is involved in the progression of leukoaraiosis. Asymmetric dimethylarginine is a competitive inhibitor of nitric oxide, which is highly expressed in patients with leukoaraiosis. Dimethylarginine dimethylaminohydrolase (DDAH) is a hydrolytic enzyme that is primarily responsible for eliminating asymmetric dimethylarginine, and it plays a role in the pathogenesis of cardiovascular and cerebrovascular diseases. The DDAH2 subtype is expressed in organs rich in induced nitric oxide synthase, including the heart, the placenta, and the cerebral endothelium during cerebral ischemia, in the stress state, or under neurotoxicity. Overexpression of the DDAH2 gene can inhibit asymmetric dimethylarginine-induced peripheral circulating endothelial cell dysfunction. However, it is unknown whether this polymorphism regulates plasma asymmetric dimethylarginine levels in patients with leukoaraiosis. In this double-blind study, we recruited 46 patients with leukoaraiosis and 46 healthy, matched controls. Plasma asymmetric dimethylarginine levels were determined using enzyme-linked immunoassays. Genomic DNA was isolated from whole blood samples, and polymerase chain reaction, SmaI restriction enzyme digestion, restriction fragment length polymorphisms, and agarose electrophoresis were used to detect DDAH2 (-449 G/C) gene polymorphisms. The results revealed that 95.65% of leukoaraiosis patients had recessive genetic models (GG and CG), while 89.13% of healthy control subjects had dominant genetic models (CC and CG). There was a significant difference in the genotype composition ratio between leukoaraiosis patients and healthy controls (P = 0.0002). The frequency of G alleles in the leukoaraiosis patients (71.74%) was significantly higher than in healthy controls, whereas the frequency of C alleles was lower (χ2 = 13.9580, P = 0.0002). Furthermore, asymmetric dimethylarginine concentrations in subjects with the GG genotype were significantly higher than in subjects with the CG and CC genotypes (Kruskal-Wallis H = 24.5955, P < 0.0001). In addition, the GG genotype of DDAH2 (-449 G/C) was more common in patients with leukoaraiosis. These findings suggest that the G allele of DDAH2 (-449 G/C) is a risk factor for leukoaraiosis morbidity and is correlated with high levels of asymmetric dimethylarginine. This study was approved by the Institutional Ethics Committee of The 2nd Affiliated Hospital of Harbin Medical University of China (approval No. KY2016-177) on July 28, 2016.

Divergence of affinities, serotypes and virulence factor between CTX-M Escherichia coli and non-CTX-M producers.

This study was undertaken to discern the differences of the multi-locus sequence typing (MLST), O serogroups, and virulence factors among 34 CTX-M-1 Escherichia coli, 49 CTX-M-9 strains and 23 non-CTX-M isolates from chickens in Henan province, China. The MLST scheme yielded 34 sequence types, in which ST155 and ST359 were frequent (17% and 15%, respectively) and associated with zoonotic disease. The irp-2 (20% versus 2%, P = 0.0001), traT (85.3% versus 56.5%, P = 0.019), and sfaS (70.6% versus 0, P = 0.021) were significantly more prevalent in CTX-M-1 E. coli than in non-CTX-M producers. Also, CTX-M-9 isolates carried more irp-2 (17% versus 2%, P = 0.023), iroN (71.4% versus 39.1%, P = 0.019), and iss (79.6% versus 39.1%, P = 0.002) genes. In conclusion, although the 106 isolates encompassed a great genetic diversity, the CTX-M isolates harbored more virulence factor genes than non-CTX-M producers.

Design, synthesis and pharmacological evaluation of a novel PEG-cRGD-conjugated irinotecan derivative as potential antitumor agent.

A novel PEG-cRGD-conjugated irinotecan derivative BGC0222 was designed and synthesized as antitumor agent. Antitumor activity screening assay indicated that BGC0222 exhibited better in vitro antiproliferation activity than irinotecan and NKTR-102 against HT29, MIA PaCa-2 and MCF-7 tumor cell lines, with IC50 of 1.83 ±â€¯0.09 µM, 3.95 ±â€¯0.16 µM and 0.68 ±â€¯0.04 µM, respectively, while it displayed better in vivo antiproliferation activity than irinotecan and NKTR-102 in HT-29, MIA PaCa-2, NCI-H446, U-87 MG and MDA-MB-231 xenograft models. The action mechanism of BGC0222 was then investigated by integrin-binding competition (IBC) and chick chorioallantoic membrane (CAM) angiogenesis assays, which indicated that BGC0222 may exert antitumor activity by binding to αvß3 target and consequently inducing neovascularization effect. Pharmacokinetic analysis showed that BGC0222 could slowly and steadily release irinotecan, which was subsequently metabolized into 7-ethyl-10-hydroxycamptothecin (SN-38) in the whole blood.

[The effects of sexually transmitted infections (STI)/AIDS behavioral intervention among female sex workers].

OBJECTIVE: To explore the effective sexually transmitted infections (STI)/AIDS intervention strategies among female sex workers at the metropolis areas with low prevalence. METHODS: A comprehensive intervention was carried out among female sex workers in eight recreation establishments which have representative characters in Chaoyang district, and the effects of intervention was subsequently evaluated by a questionnaire from September 2005 to February 2006. The data were analyzed by SPSS11.5. RESULTS: The study subjects aged 17-40 year old (25.22 +/- 5.81), and 203 (89. 82%) of them had high or middle school education background. 166 were unmarried, and 205 (90.70%) had no job, and 244 (99. 12%) subjects were migrants. After intervention, the correct answer rates for the knowledge of STI/ AIDS rose from 52.6% to 75.4% (chi2 = 22.701, P < 0.01); and the correct use of condom were higher than those of baseline, with the rise from 22.12% to 34.76% (chi2 = 8.14, P < 0.05). CONCLUSION: The STI/AIDS comprehensive intervention measures were effective and should be evaluated and generalized in the similar metropolis regions.

Home-based HIV testing for men who have sex with men in China: a novel community-based partnership to complement government programs.

BACKGROUND: The coverage of HIV testing among Chinese men who have sex with men (MSM) remains low after the scale-up of free HIV testing at government-sponsored testing sites. We evaluated the feasibility of home-based HIV self-testing and the willingness to be HIV tested at community-based organizations (CBO). METHODS: We recruited MSM via on-line advertisement, where they completed an on-line informed consent and subsequent questionnaire survey. Eligible MSM received HIV rapid testing kits by mail, performed the test themselves and reported the result remotely. RESULTS: Of the 220 men taking a home-based HIV self-testing, 33 MSM (15%) were seropositive. Nearly 65% of the men reported that they were willing to take HIV testing at CBO, while 28% preferred receiving free HIV testing in the government programs at local Centers for Disease Control and Prevention (CDC). Older and lower-income MSM, those who self-reported homosexual orientation, men with no history of sexually transmitted diseases and a lower number of sexual partners in the past six months were associated with preference for taking HIV testing at CBOs. The top three self-reported existing barriers for HIV testing were: no perception of HIV risk (56%), fear of an HIV positive result being reported to the government (41%), and fear of a positive HIV test result (36%). CONCLUSION: Home-based HIV self-testing is an alternative approach for increasing the coverage of HIV testing among Chinese MSM. CBO-based HIV testing is a potential alternative, but further studies are needed to evaluate its feasibility.