Efficacy and safety of metformin and sitagliptin based triple antihyperglycemic therapy (STRATEGY): a multicenter,randomized, controlled,non-inferiority clinical trial

Despite the current guideline’s recommendation of a timely stepwise intensification therapy, the “clinical inertia”, termed as the delayed treatment intensification, commonly exists in the real world, which may be partly due to the relatively little substantial evidence and no clear consensus regarding the efficacy and safety of triple oral agents in patients inadequately controlled with dual therapy. In this clinical trial performed in 237 centers in China, 5,535 type 2 diabetic patients inadequately controlled by previous therapies were treated with a stable metformin/sitagliptin dual therapy for 20 weeks. The patients who did not reach the glycated hemoglobin A1c (HbA1c) goal were then further randomized into glimepiride, gliclazide, repaglinide, or acarbose group for an additional 24-week triple therapy. A mean HbA1c reduction of 0.85% was observed when sitagliptin was added to the patients inadequately controlled with metformin in 16 weeks. Further HbA1c reductions in the 24-week triple therapy stage were 0.65% in glimepiride group, 0.70% in gliclazide group, 0.61% in repaglinide group, and 0.45% in acarbose group. The non-inferiority criterion for primary hypotheses was met for gliclazide and repaglinide, but not for acarbose, compared with glimepiride, when added to metformin/sitagliptin dual therapy. The incidences of adverse events (AEs) were 29.2% in the dual therapy stage and 30.3% in the triple therapy stage. Metformin/sitagliptin as baseline therapy, with the addition of a third oral antihyperglycemic agent, including glimepiride, gliclazide, repaglinide, or acarbose, was effective, safe and well-tolerated for achieving an HbA1c <7.0% goal in type 2 diabetic patients inadequately controlled with previous therapies. The timely augmentation of up to three oral antihyperglycemic agents is valid and of important clinical benefit to prevent patients from exposure to unnecessarily prolonged hyperglycemia.     

Targeting WW domains linker of HECT-type ubiquitin ligase Smurf1 for activation by CKIP-1

E3 ubiquitin ligases are final effectors of the enzyme cascade controlling ubiquitylation. A central issue in understanding their regulation is to decipher mechanisms of their assembly and activity. In contrast with RING-type E3s, fewer mechanisms are known for regulation of HECT-type E3s. Smad ubiquitylation regulatory factor 1 (Smurf1), a C2-WW-HECT-domain E3, is crucial for bone homeostasis, in which it suppresses osteoblast activity. However, whether and how its activity is regulated remains unclear. Here we show that Smurf1, but not Smurf2, interacts with casein kinase-2 interacting protein-1 (CKIP-1), resulting in an increase in its E3 ligase activity. Surprisingly, CKIP-1 targets specifically the linker region between the WW domains of Smurf1, thereby augmenting its affinity for and promoting ubiquitylation of the substrate. Moreover, CKIP-1-deficient mice undergo an age-dependent increase in bone mass as a result of accelerated osteogenesis and decreased Smurf1 activity. These findings provide evidence that the WW domains linker is important in complex assembly and in regulating activity of HECT-type E3s and that CKIP-1 functions as the first auxiliary factor to enhance the activation of Smurf1.     

Environmental cadmium exposure and forearm bone density

Environmental exposure to cadmium may give rise to osteomalacia combined with renal dysfunction, so called 'Itai-Itai disease', which was endemic in the heavily polluted area in Japan. The main focus of this study was to investigate whether environmental exposure to cadmium is associated with low bone mass in a population living near a smelter. A total of 790 persons (302 males and 488 females), who were all over 35 years old and resided in areas near a lead, zinc and cadmium smelter and in a control area in southeast China, completed a questionnaire, and bone mineral density was measured by SPA-4 single photon absorptiometry at the radius and ulna. Cadmium content of urine was determined by graphite-furnace atomic absorption spectrophotometry as a measure of dose. The present study shows that forearm bone densities were negatively correlated with urinary cadmium excretion (p < 0.001) and forearm bone density decreased linearly with age (p < 0.001) and urinary cadmium (p < 0.01), suggesting a dose-effect relationship between cadmium dose and bone mineral density. Based on the World Health Organization criteria, (bone mineral density < -2.5 SDs below the normal young adult), the prevalence of osteoporosis in women increased from 34.0% in the control area to 51.9% in the heavily polluted area (p < 0.01) among subjects over 50 years old, and the odds ratio value was 2.09 (95% CI: 1.08-4.03) for the highly polluted area compared with the control area. A striking observation in the study was a marked increase of the prevalence of fracture in the cadmium-polluted area in both sexes. It was concluded that environmental exposure to cadmium is associated with an increased loss of bone mineral density in both gender, leading to osteoporosis and increased risk of fractures, especially in the elderly and in females.     

Low resolution structure of subunit b (b (22-156)) of Escherichia coli F(1)F(O) ATP synthase in solution and the b-delta assembly

The first low resolution solution structure of the soluble domain of subunit b (b _22–156) of the Escherichia coli F₁F_O ATPsynthase was determined from small-angle X-ray scattering data. The dimeric protein has a boomerang-like shape with a total length of 16.2 ± 0.3 nm. Fluorescence correlation spectroscopy (FCS) shows that the protein binds effectively to the subunit δ, confirming their described neighborhood. Using the recombinant C-terminal domain (δ_91–177) of subunit δ and the C-terminal peptides of subunit b, b _120–140 and b _140–156, FCS titration experiments were performed to assign the segments involved in δ–b assembly. These data identify the very C-terminal tail b _140–156 to interact with δ_91–177. The novel 3D structure of this peptide has been determined by NMR spectroscopy. The molecule adopts a stable helix formation in solution with a flexible tail between amino acid 140 to 145.     

Laboratory and field evaluations of extracts from Rhododendron molle flowers as insect growth regulator to imported cabbage worm, Pieris rapae L. (Lepidoptera:Pieridae)

The insect growth regulating properties of rhodojaponin-III (Abbr. R-III) and ethyl acetate (EtOAc) extract from Rhododendron molle G. Don flowers against imported cabbage worm, Pieris rapae L., were determined under laboratory and field conditions. The values of IC₅₀ (the median of concentration for inhibiting weight increase) for R-III and EtOAc extract were 6.78 p.p.m. and 70.29 p.p.m. against 3rd instar larvae and 13.72 p.p.m. and 346.00 p.p.m. against 5th instar larvae, respectively. R-III and EtOAc extract also could reduce pupating rate, pupal weight, emergence rate and extend the duration of development. Thus development of insects was inhibited significantly and development index decreased. R-III would be superior to toosendanin as insect growth regulator. EtOAc extract 1000 p.p.m. mixture with molosultap 500 p.p.m. could achieve an effective control rate of 87.34% against P. rapae in field trials when adjusted cumulative insect-days were used as index.     

Study on the photo-generation of superoxide radicals in Photosystem II with EPR spin trapping techniques

Direct EPR evidence of the photo-generation of superoxide radicals (O₂ ^–.) was obtained by using a novel spin trapping probe in spinach Photosystem II (PS II) membrane fragments. The production of O₂ ^–. was detected by following the formation of 5-diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO) superoxide adducts (DEPMPO-OOH). The inhibition of O₂ ^–. formation by 3-(3,4-dichlorophenyl) -1,1-dimethylurea (DCMU) and the 77 K fluorescence spectrum indicated that O₂ ^–. were generated from PS II, not from PS I. The inhibition of O₂ ^–. formation by DCMU also suggested that O₂ ^–. were generated from the Q_Bbinding site, not at a site prior to DCMU blockage. The extrinsic proteins and Mn are very important to eliminate O₂ ^–., showing that the oxygen-evolving system is involved in O₂ ^–. removal rather than production.This revised version was published online in October 2005 with corrections to the Cover Date.     

国内生物基材料产业发展现状

近年来,生物基材料正逐步成为引领当代世界科技创新和经济发展的又一新的主导产业。文章综述了国内生物基材料产业的最新进展,对整个生物基材料产业市场进行了综合分析,包括生物基化学品如乳酸、1,3-丙二醇、丁二酸等,可生物降解生物基塑料如二元酸二元醇共聚酯、聚乳酸、二氧化碳共聚物、聚羟基烷酸酯、聚己内酯、热塑性生物质塑料,非生物降解生物基塑料如生物基聚酰胺、聚对苯二甲酸丙二醇酯、生物基聚氨酯,以及生物基纤维等材料的产业现状。     

Effects of ELF magnetic fields on protein expression profile of human breast cancer cell MCF7

Extremely Low Frequency Magnetic Fields (ELF MF) has been considered as a “possible human carcinogen” by International Agency for Research on Cancer (IARC) while credible mechanisms of its carcinogenicity remain unknown. In this study, a proteomics approach was employed to investigate the changes of protein expression profile induced by ELF MF in human breast cancer cell line MCF7, in order to determine ELF MF-responsive proteins. MCF7 cells were exposed to 50 Hz, 0.4 mT ELF MF for 24 h and the changes of protein profile were examined using two dimensional electrophoresis. Up to 6 spots have been statistically significantly altered (their expression levels were changed at least 5 fold up or down) compared with sham-exposed group. 19 ones were only detected in exposure group while 19 ones were missing. Three proteins were identified by LC-IT Tandem MS as RNA binding protein regulatory subunit Proteasome subunit beta type 7 precursor and Translationally Controlled Tumor Protein. Our finding showed that 50 Hz, 0.4 mT ELF MF alternates the protein profile of MCF7 cell and may affect many physiological functions of normal cell and 2-DE coupled with MS is a promising approach to elucidating cellular effects of electromagnetic fields.     

Structure-based design of a T-cell receptor leads to nearly 100-fold improvement in binding affinity for pepMHC

T-cell receptors (TCRs) are proteins that recognize peptides from foreign proteins bound to the major histocompatibility complex (MHC) on the surface of an antigen-presenting cell. This interaction enables the T cells to initiate a cell-mediated immune response to terminate cells displaying the foreign peptide on their MHC. Naturally occurring TCRs have high specificity but low affinity toward the peptide-MHC (pepMHC) complex. This prevents the usage of solubilized TCRs for diagnosis and treatment of viral infections or cancers. Efforts to enhance the binding affinity of several TCRs have been reported in recent years, through randomized libraries and in vitro selection. However, there have been no reported efforts to enhance the affinity via structure-based design, which allows more control and understanding of the mechanism of improvement. Here, we have applied structure-based design to a human TCR to improve its pepMHC binding. Our design method evolved based on iterative steps of prediction, testing, and generating more predictions based on the new data. The final design function, named ZAFFI, has a correlation of 0.77 and average error of 0.35 kcal/mol with the binding free energies of 26 point mutations for this system that we measured by surface plasmon resonance (SPR). Applying the filter that we developed to remove nonbinding predictions, this correlation increases to 0.85, and the average error decreases to 0.3 kcal/mol. Using this algorithm, we predicted and tested several point mutations that improved binding, with one giving over sixfold binding improvement. Four of the point mutations that improved binding were then combined to give a mutant TCR that binds the pepMHC 99 times more strongly than the wild-type TCR.