Characterizing DNA methylation patterns in pancreatic cancer genome

We performed a global methylation profiling assay on 1505 CpG sites across 807 genes to characterize DNA methylation patterns in pancreatic cancer genome. We found 289 CpG sites that were differentially methylated in normal pancreas, pancreatic tumors and cancer cell lines. We identified 23 and 35 candidate genes that are regulated by hypermethylation and hypomethylation in pancreatic cancer, respectively. We also identified candidate methylation markers that alter the expression of genes critical to gemcitabine susceptibility in pancreatic cancer. These results indicate that aberrant DNA methylation is a frequent epigenetic event in pancreatic cancer; and by using global methylation profiling assay, it is possible to identify these markers for diagnostic and therapeutic purposes in this disease.     

Preparation and in vitro characterization of paclitaxel containing poly(lactic acid co-castor oil)-based nanodispersions

Paclitaxel-loaded nanosized particles (NPs) of poly(lactic acid co castor oil) 60:40 % w/w- (p(DLLA:CO) were prepared by nanoprecipitation method and lyophilized using cryoprotectants. The prepared nanoparticles were evaluated for encapsulation efficiency and drug release. The formulations were also characterized by Fourier transform infrared (FTIR), powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and particle size. From the SEM microphotographs, NPs were obtained in the form of long, flat scales which are similar to rod/bone and rose flower-like shaped nanosized drug delivery systems. FTIR, XRD and DSC results proved that the drug is encapsulated in the polymeric matrix in the amorphous state. Formulations obtained were below 400 nm.     

Notch signaling pathway targeted therapy suppresses tumor progression and metastatic spread in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDA) remains a lethal human malignancy with historically limited success in treatment. The role of aberrant Notch signaling, which requires the constitutive activation of γ-secretase, in the initiation and progression of PDA is well defined and inhibitors of this pathway are currently in clinical trials. Here we investigated the in vivo therapeutic effect of PF-03084014, a selective γ-secretase inhibitor, alone and in combination with gemcitabine in pancreatic cancer xenografts. PF-03084014 treatment inhibited the cleavage of nuclear Notch 1 intracellular domain and Notch targets Hes-1 and Hey-1. Gemcitabine treatment showed good response but not capable of inducing tumor regressions and targeting the tumor-resident cancer stem cells (CD24⁺CD44⁺ and ALDH⁺ tumor cells). A combination of PF-03084014 and gemcitabine treatment resulted tumor regression in 3 of 4 subcutaneously implanted xenograft models. PF-03084014, and in combination with gemcitabine reduced putative cancer stem cells, indicating that PF-03084014 target the especially dangerous and resilient cancer stem cells within pancreatic tumors. Tumor re-growth curves plotted after drug treatments demonstrated that the effect of the combination therapy was sustainable than that of gemcitabine. Notably, in a highly aggressive orthotopic model, PF-03084014 and gemcitabine combination was effective in inducing apoptosis, inhibition of tumor cell proliferation and angiogenesis, resulting in the attenuation of primary tumor growth as well as controlling metastatic dissemination, compared to gemcitabine treatment. In summary, our preclinical data suggest that PF-03084014 has greater anti-tumor activity in combination with gemcitabine in PDA and provides rationale for further investigation of this combination in PDA.     

Population pharmacokinetics of enfuvirtide in HIV-1-infected pediatric patients over 48 weeks of treatment

The objective of this study was to characterize the population pharmacokinetics of enfuvirtide in HIV-1-infected children and adolescents. HIV-infected patients received combination antiretroviral therapy, including enfuvirtide 2.0 mg/kg subcutaneously, twice daily. Serial and trough blood samples were collected up to 48 weeks. NONMEM was used for population pharmacokinetic analysis. Enfuvirtide exposure was calculated from individual parameter estimates derived from the final model. A total of 218 samples from 43 patients were included in the analysis. Enfuvirtide plasma concentration-time data were described by a 1-compartment model with first-order absorption and elimination. The addition of each subject's actual body weight as a covariate affected CL/F but not V/F or K(a). The population CL/F, V/F, and K(a) for a 33-kg reference patient was 1.31 L/h, 2.31 L, and 0.105 h(-1), respectively. The final model was CL/F (L/h) = 1.31 . (body weight/33 [kg])(0.721). Age did not affect enfuvirtide exposure. These results confirm the appropriateness of body weight-based pediatric enfuvirtide dosing.     

NEW INVESTIGATOR AWARD FINALISTSNIA0001Induction of differentiation in human preadipocytes may contribute to adipogenic effect of human adenovirus Ad-36

Human adenovirus Ad-36 causes adiposity in animal models and shows association with human obesity. The mechanism involved is unknown. We previously reported that Ad-36 enhances differentiation of 3T3-L1 preadipocytes and E4orf-1 gene of the virus is responsible for the adipogenic effect in the rodent cell line. We undertook a three-step approach to investigate the role of preadipocyte differentiation in adipogenic effect of Ad-36. First, we showed that the viral mRNA is expressed in adipose-derived stem cells (ASC) of animals experimentally infected with Ad-36. Infection of rats with Ad-36 resulted in increased epididymal fat pad weight and the expression of Ad-36 E4orf-1 mRNA was detected in ASC isolated from the fat pads. Next, we determined if humans naturally infected with Ad-36 will show greater preadipocyte differentiation. Subcutaneous adipose-tissue samples from 33 Pima Indian subjects were screened by nested-PCR specific for Ad-36 DNA. Nine subjects (27%) had Ad-36 DNA. A blinded comparison of their ASC showed greater differentiation to adipocytes for the Ad-36 DNA positive subjects ( P =  0.06) compared to the Ad-36 DNA negative group. Finally, we used a direct approach. Human-ASC when infected with Ad-36 showed spontaneous replication, differentiation, and lipid accumulation, which was significantly greater than the uninfected controls ( P  < 0.01). Ad-36 induced lipid accumulation in human-ASC increased in response to the viral load and the lipogenic response was observed regardless of the donor gender and over an age range of 22–57 years. These results suggest that ability of Ad-36 to induce preadipocyte differentiation may play a role in human adiposity.     

高位胸段硬膜外麻醉下清醒病人的冠状动脉搭桥手术

目的　了解在高位胸段硬膜外麻醉下避免全麻行非体外循环心脏跳动下冠状动脉搭桥手术的可行性。方法　硬膜外麻醉下对 2 5例清醒病人行非体外循环心脏跳动下冠状动脉搭桥手术 ,没有气管插管全麻 ,所有病人在手术前晚行硬膜外置管。结果　总共搭桥 71支 (1支 11例 ,2支 5例 ,3支 6例 ,4支 3例 )。除 1例因为术中出现室颤转为全麻和体外循环外 ,2 4例在硬外麻作为唯一麻醉下完成非体外循环心脏跳动下冠状动脉搭桥手术。除 2例行左胸小切口外其余行正中切口 ;其中 6例为再次手术 ;平均每例搭桥2 8支 ,没有手术死亡。术后在复苏室和病房住院时间分别为 (16 2± 4 2 )h和 (3 2 4± 1 2 )d。结论　本组的早期经验提示在没有气管插管全麻、病人清醒下可以行多支冠状动脉搭桥术     

Protective effect of Picroliv, the active constituent of Picrorhiza kurroa, against chemical carcinogenesis in mice.

Cancer chemoprevention of chemically induced tumours by Picroliv, an iridoid glycoside mixture purified from Picrorhiza kurroa, was studied on 20-methylcholanthrene (20-MC)-induced sarcoma model and 7,12-dimethylbenz[a]anthracene (DMBA)-initiated papilloma formation in BALB/c mice. Administration of Picroliv (100 and 200 mg/kg, p.o) inhibited the sarcoma development by 47 and 53% as estimated on day 200 after 20-MC administration. Control animals started dying of tumour burden 76 days after 20-MC administration and all animals were dead by day 170, while 60 and 66% of the animals survived in the Picroliv treated group, 100 and 200 mg/kg, respectively. Picroliv exhibited anti-tumour-promoting activity on a two-stage carcinogenesis test on mouse skin using DMBA as an initiator and croton oil as a promoter. Topical application of Picroliv (1 and 5 mg/mouse) 30 minutes prior to that of croton oil application resulted in a 50 and 60% reduction in the number of animals that developed papillomas, and 48 and 64% reduction in the number of papillomas per mouse. There was also a delay in the onset of first skin tumour in the group of animals treated with Picroliv. Oral administration of Picroliv (150 mg/kg, p.o.) prior to DMBA application delayed the onset of papillomas and the percent of mice (60%) with tumours indicates that Picroliv inhibited the tumour initiation induced by DMBA. Picroliv administration was also found to increase the life span of transplanted Dalton's Lymphoma Ascites (DLA) and Ehrlich Ascites Carcinoma (EAC) harboring mice and reduced the volume of transplanted solid tumours.     

The Mitochondrial Genome And Human Mitochondrial Diseases

To date, more than 100 point mutations and several hundreds of structural rearrangements of mitochondrial DNA (mtDNA) are known too be connected with characteristic neuromuscular and other mitochondrial syndromes varying from those causing death at the neonatal stage to diseases with late ages of onset. The immediate cause of mitochondrial disorders is a defective oxidative phosphorylation. Wide phenotypic variation and the heteroplasmy phenomenon, which some authors include in mutation load, are characteristic of human mitochondrial diseases. As the numbers of cases identified and pedigrees described increase, data on the genotype-phenotype interaction and the structure and frequency of pathogenic and conditionally pathogenic mtDNA mutations in human populations are rapidly accumulated. The data on the genetics and epidemiology of mitochondrial diseases are not only important for differential diagnosis and genetic counseling. Since both neutral and mildly pathogenic mutations of mtDNA are progressively accumulated in maternal phyletic lines, molecular analysis of these mutations permits not only reconstruction of the genealogical tree of modern humans, but also estimation of the role that these mutations play in natural selection.