Quantitative analysis of cytoplasmic actin gene promoter and nuclear polyhedrosis virus immediate-early promoter activities in various tissues of silkworm Bombyx mori using recombinant Autographa californica nuclear polyhedrosis virus as vector

Cassettes harboring luciferase reporter driven by Bombyx mori cytoplasmic actin gene promoter (A3) (671 bp) and B. mori nuclear polyhedrosis virus immediate-early promoter (IE-1) (580 bp) were transferred to the bacmid AcΔEGT to generate the recombinant Autographa californica nuclear polyhedrosis viruses, AcNPVA3Luc and AcNPVIELuc, respectively. Recombinant baculoviruses were injected into the hemocoele of newly ecdysed 5th instar larvae. The activities of the A3 and IE-1 promoters in various tissues were measured by luciferase activity assay and normalized by the copy number of recombinant virus. Results showed that the activity of the A3 promoter was approximately 10-fold higher than the IE-1 promoter. The promoter activities of A3 and IE-1 were highest in the silk gland, followed by fat body, middle gut, Malpighian tubule, and hemocyte. In silk gland, activity of the two promoters was highest in posterior silk gland, followed by middle and anterior silk glands. The difference in promoter activities reflects the growth speed of tissue in silkworm larvae. The activity of the A3 promoter remained unchanged and was not inhibited significantly by viral factors at least 3–4 d post injection of rAcNPV.     

Association of mitochondrial haplogroup D and risk of esophageal cancer in Taihang Mountain and Chaoshan areas in China

Both the Taihang Mountain area in north-central China and Chaoshan area in the southeastern littoral of China are areas with high risk of esophageal cancer (EC). Our previous study confirmed that populations from the two areas might share similar matrilineal backgrounds and found that mitochondrial DNA (mtDNA) haplogroup D, especially subhaplogroups D4a and D5a, might be genetic background markers of EC in Chaoshan area. Here, to further determine whether D4a, D5a, and D might be susceptibility markers for EC in the two high-risk areas, we performed a case–control study with larger samples and analyzed the distributions of these three haplogroups in subjects (controls [n = 898] and patients [n = 768]) from the two areas. D4a haplogroup was significantly associated with increased risk of EC in Taihang Mountain subjects, especially women. D5 haplogroup was associated with EC at the general population level in the Taihang Mountain area and in subjects ≤ 60 years, especially women ≤ 60 years, in the Chaoshan area. D haplogroup was associated with EC only in subjects ≤ 60 years, especially men ≤ 60 years, in the Chaoshan area. D4a and D5 showing positive association with EC in the Taihang Mountain area became the predominant subhaplogroups of D in Chaoshan controls. In conclusion, D, D4a, and D5 haplogroups might be susceptibility markers for EC in the two high-risk areas in China, particularly D4a and D5 for the Taihang Mountain area and D and D5 for the Chaoshan area.     

Synthesis and evaluation of nanoglobular macrocyclic Mn(II) chelate conjugates as non-gadolinium(III) MRI contrast agents

Because of the recent observation of the toxic side effects of Gd(III) based MRI contrast agents in patients with impaired renal function, there is strong interest on developing alternative contrast agents for MRI. In this study, macrocyclic Mn(II) chelates were conjugated to nanoglobular carriers, lysine dendrimers with a silsesquioxane core, to synthesize non-Gd(III) based MRI contrast agents. A generation 3 nanoglobular conjugate of Mn(II)-1,4,7-triaazacyclononane-1,4,7-triacetate-GA amide (G3-NOTA-Mn) was also synthesized and evaluated. The per ion T(1) and T(2) relaxivities of G2, G3, G4 nanoglobular Mn(II)-DOTA monoamide conjugates decreased with increasing generation of the carriers. The T(1) relaxivities of G2, G3, and G4 nanoglobular Mn(II)-DOTA conjugates were 3.3, 2.8, and 2.4 mM(-1) s(-1) per Mn(II) chelate at 3 T, respectively. The T(1) relaxivity of G3-NOTA-Mn was 3.80 mM(-1) s(-1) per Mn(II) chelate at 3 T. The nanoglobular macrocyclic Mn(II) chelate conjugates showed good in vivo stability and were readily excreted via renal filtration. The conjugates resulted in much less nonspecific liver enhancement than MnCl(2) and were effective for contrast-enhanced tumor imaging in nude mice bearing MDA-MB-231 breast tumor xenografts at a dose of 0.03 mmol Mn/kg. The nanoglobular macrocyclic Mn(II) chelate conjugates are promising nongadolinium based MRI contrast agents.     

MGMT Promoter Methylation Correlates with an Overall Survival Benefit in Chinese High-Grade Glioblastoma Patients Treated with Radiotherapy and Alkylating Agent-Based Chemotherapy: A Single-Institution Study

Promoter methylation of the O⁶-methylguanine-DNA-methyltransferase (MGMT) gene has been considered a prognostic marker and has become more important in the treatment of glioblastoma. However, reports on the correlation between MGMT and clinical outcomes in Chinese glioblastoma patients are very scarce. In this study, quantitative methylation data were obtained by the pyrosequencing of tumor tissues from 128 GBM patients. The median overall survival (OS) was 13.1 months, with a 1-year survival of 45.3%. The pyrosequencing data were reproducible based on archived samples yielding data for all glioblastomas. MGMT promoter methylation was detected in 75/128 cases (58.6%), whereas 53/128 (41.4%) cases were unmethylated. Further survival analysis also revealed that methylation was an independent prognostic factor associated with prolonged OS but not with progression-free survival (PFS) (p = 0.029 and p = 0.112, respectively); the hazard radios were 0.63 (95% CI: 0.42–0.96) and 0.72 (95% CI: 0.48–1.09), respectively. These data indicated that MGMT methylation has prognostic significance in patients with newly diagnosed high-grade glioblastoma undergoing alkylating agent-based chemotherapy after surgical resection.     

Oligomerization and regulated proteolytic processing of angiopoietin-like protein 4

Angiopoietin-like protein 4 (Angptl4) is a recently identified circulating protein expressed primarily in adipose tissue and liver. Also known as peroxisome proliferator-activated receptor (PPAR)-gamma angiopoietin-related, fasting induced adipose factor, and hepatic fibrinogen/angiopoietin-related protein, recombinant Angptl4 causes increase of plasma very low density lipoprotein levels by inhibition of lipoprotein lipase activity. Similar to angiopoietins and other angiopoietin-like proteins, Angptl4 contains an amino-terminal coiled-coil domain and a carboxyl-terminal fibrinogen-like domain. We report here that Angptl4 is evolutionarily conserved among several mammalian species and that full-length Angptl4 protein is an oligomer containing intermolecular disulfide bonds. Oligomerized Angptl4 undergoes proteolytic processing to release its carboxyl fibrinogen-like domain, which circulates as a monomer. Angptl4's N-terminal coiled-coil domain mediates its oligomerization, which by itself is sufficient to form higher order oligomeric structure. Adenovirus-mediated overexpression of Angptl4 in 293 cells shows that conversion of full-length, oligomerized Angptl4 is mediated by a cell-associated protease activity induced by serum. These findings demonstrate a novel property of angiopoietin-like proteins and suggest that oligomerization and proteolytic processing of Angptl4 may regulate its biological activities in vivo.     

DNA deposition on carbon electrodes under controlled dc potentials

The native calf-thymus DNA molecule fully dispersed in solution was deposited onto highly oriented pyrolytic graphite, carbon fiber column and disk electrodes under controlled dc potentials. X-ray photoelectron spectroscopy, atomic force microscopy and electrochemical investigations indicated that network structures of DNA could be formed on various carbon electrode surfaces resulting in significant surface enlargement. The conformation, conductivity and stability of the deposited DNA layer largely depended on the concentration of the DNA deposition solution, the applied dc potential and the mode of electric field. The optimal condition for deposition of the DNA on carbon fiber disk electrode was determined as a deposition potential of 1.8 +/- 0.3 V versus 50 mM NaCl-Ag/AgCl and a deposition DNA solution of 0.1 mg ml(-1). Under this condition, the DNA was covalently bonded on the electrode surface forming a three-dimensional modified layer, generating a 500-fold enlarged effective electrode surface area and similarly enlarged current sensitivity for redox species, such as Co(phen)3(3+). A possible mechanism for the formation of DNA networks is proposed.