Bioequivalence evaluation of 2 tablet formulations of entecavir in healthy chinese volunteers: a single-dose, randomized-sequence, open-label crossover study

A randomized, 2-way crossover study was conducted in healthy Chinese male volunteers to evaluate the bioequivalence of a new generic formulation of entecavir (CAS 142217-69-4) tablets (test) and the available branded formulation (reference) to meet the requirements for marketing the test product in China. Test and reference tablets were administered as a single dose on 2 treatment days separated by a 2-week washout period. Blood samples were collected for a period of 24 h following drug administration. Plasma concentration of entecavir was determined by a liquid chromatography-tandem mass spectrometry (LC/MS/MS) method. Pharmacokinetic parameters were calculated using a noncompartmental model. Bioequivalence was determined by calculating 90% CIs for the ratios of Cmax, AUC0-t and AUC0-∞ values for the test and reference products. Tolerability was assessed by monitoring vital signs, laboratory tests and interviews with the volunteers before administration and every 2 h during the study. The 90% CIs of entecavir for Cmax, AUC0-t and AUC0-∞ were 95.2-106.9%, 98.4-104.6% and 97.3-104.4%, respectively, which fell within the interval of 80-125%. No clinically important adverse effects were reported. These results suggested that the test formulation of entecavir tablets met the regulatory criterion for bioequivalence to the reference formulation.

Water's potential role: Insights from studies of the p53 core domain

Soluble proteins with amyloidogenic propensity such as the tumor suppressor protein p53 have high proportion of incompletely desolvated backbone H bonds (HB). Such bonds are vulnerable to water attack, thus potentially leading to the misfolding of these proteins. However, it is still not clear how the surrounding solvent influences the protein native states. To address this, systematic surveys by molecular dynamics simulations and entropy analysis were performed on the p53 core domain in this work. We examined seven wild/mutant X-ray structures and observed two types of water-network hydration in three "hot hydration centers" (DNA- or small molecule- binding surfaces of the p53 core domain). The "tight" water, resulting from the local collective hydrogen-bond interactions, is probably fundamental to the protein structural stability. The second type of water is highly "dynamical" and exchanges very fast within the bulk solution, which is unambiguously assisted by the local protein motions. An entropy mapping of the solvent around the protein and a temperature perturbation analysis further present the main features of the p53 hydration network. The particular environment created by different water molecules around the p53 core domain also partly explains the structural vulnerabilities of this protein.

Caffeic acid phenethyl ester prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurodegeneration

Parkinson's disease is associated with the loss of dopaminergic neurons in the substantia nigra and decreased striatal dopamine levels. We now report that caffeic acid phenethyl ester (CAPE), an active component of propolis, attenuated dopaminergic neurodegeneration and dopamine loss in the MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mouse model of Parkinson's disease. The neuroprotective effect of CAPE was associated with marked reductions in inducible nitric oxide synthase (iNOS) and caspase 1 expression. Additionally, CAPE inhibited MPP+-induced neurotoxicity in vitro and directly inhibited MPP+-induced release of cytochrome c and apoptosis inducing factor (AIF) from mitochondria. Thus, CAPE may have beneficial effects in slowing or preventing the progression of Parkinson's disease and other neurodegenerative disorders.

Genetic suppression of Akt1 activity aggravates cerebral ischemia/reperfusion injury after deep hypothermic low flow in transgenic mice

OBJECTIVE

We investigated the genetic role of the PI3K/Akt signaling pathway in Akt1 (+/-) mice after cerebral ischemia/reperfusion injury following post-surgery deep hypothermic low flow.

METHODS

3-week-old Akt1 (+/-) and wild-type C57/B6 mice were randomly and equally divided into sham-surgery and surgery groups. Surgery group mice were subjected to gradual body temperature reduction and bilateral common carotid artery occlusion for 120 min at 18.5 ± 0.5 °C, followed by artery reopening and rewarming. Occlusion was not performed in sham-surgery group animals. Regional cerebral blood flow was determined by laser Doppler flowmetry. Using reverse transcriptase-PCR, apoptotic assays, immunohistology, and Western blot analyses, we determined the apoptotic level of cerebral cells and the expression of Akt signaling pathway components.

RESULTS

Regional cerebral blood flow was decreased by ≥ 86% during bilateral common carotid artery occlusion. Akt1 (+/-) mice experienced showed mortality after 24 h of cerebral I/R, and displayed increased numbers of apoptotic cerebral cells and apoptotic protein expression levels. Western analysis revealed Akt1 hypoactivity, which led to less efficient apoptotic signaling pathway inhibition.

CONCLUSION

Akt1 suppresses the mitochondrial apoptosis signaling pathway, and Akt1 haplo-insufficiency exacerbates cerebral ischemia/reperfusion after deep hypothermic low flow conditions in mice. Akt may be a potential molecular therapeutic target for brain protection during surgery in congenital heart disease patients.

Formation of TiSi2 During Rapid Thermal Annealing: In Situ Resistance Measurements at Heating Rates From 1°C/S to 100°C/S

In VLSI technology, there is interest in monitoring the sequence of phase formation of TiSi2 (c-Ti ⇒ a-TiSi ⇒ C49 TiSi2 ⇒ C54 TiSi2), with the prospect of reducing the temperature of formation of the stable C54 TiSi2 phase. In this study, phase formation characteristics of TiSi2 during rapid thermal annealing(RTA) of Ti-Si bilayers are investigated by means of in situ four point probe resistance measurements. Ex situ X-ray diffraction(XRD) was used for phase identification and characterization. Results indicate that the same multi-step sequence of transformations precede the formation of the C54 TiSi2 phase for heating rates from 1°C/s to 100°C/s. Also, all intermediate and metastable phases which occur at l°C/s also occur at 100°C/s. Temperature dependence and kinetics of the C49 TiSi2 and the C54 TiSi2 phase formation were studied over a wide range of heating rates. Activation energies estimated for the two processes were ∼2eV and ∼5eV respectively. Finally, a new Electrical Thermal Annealing(ETA) technique for heating at rates up to 30000°C/s is introduced. Preliminary in situ resistivity measurement results of TiSi2 formation at these high heating rates are also presented.

Interdiffusion and Phase Relations in Ti-Aluminide/NB/Ti-Aluminide Composite Structures

We have studied interdiffusion and phase relations in two titanium aluminide/Nb/titanium aluminide composite structures at 1100 °C using solid state diffusion approach. The composite structures were prepared with two practical intermetallic alloys, γ (Ti-48Al-2Nb-0.3Ta, in at.%) alloy and super-α2 (Ti-25Al-10Nb-3V-1Mo, in at.%) alloy, and pure Nb sheet by diffusion bonding technique. The interfacial microstructures evolved during thermal diffusion annealing were characterized using optical microscopy, SEM, TEM and X-ray diffraction. The effect of Nb on the phase stabilities of two intermetallic alloys and the phase relations among different phases formed in the diffusion zone due to interdiffusion were analyzed in terms of rules of diffusion paths on the basis of the observed diffusion structures and experimental diffusion paths.

Microstructure Control for Thin Film Metallization

A strategy was developed for controlling hillock formation in thin metal films by controlling the fiber texture to be of a relatively “weak” orientation. Two-dimensional molecular dynamics (MD) simulations were performed to determine the parameter dependencies of texturing under ion beam assisted deposition. Simulations showed that even for film orientations that have a lower number of nearest neighbor surface bonds, the reduction in sputtering rate by ion channeling will favor the growth of the grains aligned with their channeling direction in the direction of the ion beam. Higher energies should result in greater sputtering and a higher surface roughness. Confirmatory experiments were performed by growing Al films using ion beam assisted deposition in which the Ne ion beam was normal to the substrate surface. For all energies above 0 eV/atom, the fiber texture contained a (220) component and, at high normalized energies, the fiber texture was heavily (220) dominated. Subsequent annealing at 450°C for 30 min. resulted in hillock formation in the PVD (physical vapor deposition) condition, a reduction in the hillock density by two orders of magnitude in the 120 eV/atom condition and complete elimination of hillocking above 800 eV/atom. Although the surface roughness increased with ion beam energy as modeled by MD, the surface became smoother during annealing. These results show that the fiber texture can be controlled in a thin metal film in such a way as to eliminate hillock formation, that molecular dynamics simulation is a valuable predictive tool for guiding experiments in the development of thin film microstructures and that ion beam assisted deposition is an effective, practical tool for controlling microstructures of thin metal films.

Structural features of the 5’ flanking region of the Yak (Bos grunniens) growth hormone receptor (GHR) gene (Brief Report)

Abstract. Yak (Bos grunniens) is a species of the Bovidae family living on the Qinghai-Tibetan Plateau and its adjacent territories at altitudes from 2 000–5 000 m (LUO et al. 2005, MA et al. 2009). As a multi-purpose domestic animal, yaks are indispensable to the local animal husbandry development because it can provide life necessities such as meat, milk, fur, velour manufacturing, transportation and manure for fuel to the local herdsmen. There are twelve yak populations numbered around 13.3 million in China and the Bazhou yak is one of Chinese yak populations (WIENER et al. 2003). The Growth Hormone Receptor (GHR) gene was identified as a candidate gene affecting key quantitative traits, like growth, milk yield and composition in livestock. At present, only investigations were carried out on the genetic variation in Exon-8, Intron-8 and Exon-10 of the yak GHR gene (VARVIO et al. 2008), no other information on the yak GHR gene is available. The purposes of this study were to – analyze the structural features of the 5’ flanking region of the yak GHR gene – compare the 5’ flanking region of yak GHR gene with that of other species of the Bovidae family and – construct the phylogenetic tree to indicate the evolutionary relationship among them.

p66(Shc) restrains Ras hyperactivation and suppresses metastatic behavior

Normal tissue cells survive and proliferate only while anchored to solid substrate. Conversely, transformed cells both survive and proliferate following detachment, having lost attachment context through unclear mechanisms. p66(Shc) is a focal adhesion-associated protein that reports cell attachment through a RhoA-dependent mechanosensory test. We find that human small cell lung cancer (SCLC) cells and mouse Lewis lung carcinoma (LLC), which display aggressive metastatic behavior, lack both p66(Shc) and retinoblastoma (pRB) and bypass anoikis. Re-expression of p66(Shc) in these cells restores anoikis and provides striking protection from metastasis by LLC cells in vivo. Notably, knockdown of p66(Shc) in normal epithelial cells leads to unrestrained Ras activation, preventing anoikis through downstream suppression of RhoA but blocking proliferation in a pRB-dependent manner, thus mimicking oncogenic Ras. Conversely, LLC and SCLC cells display constitutive Ras activation necessary to bypass anoikis, which is reversed by re-expression of p66(Shc). p66(Shc) therefore coordinates Ras-dependent control of proliferation and anchorage sensation, which can be defeated in the evolution of highly metastatic tumors by combined loss of both p66(Shc) and pRB.

Genotyping of the polymorphism within exon 1 of <i>Hormone Sensitive Lipase (LIPE)</i> Gene in three Chinese Yak (<i>Bos grunniens</i>) breeds by PCR-RFLP (Brief Report)

Abstract. The yak (Bos grunniens), a herbivore living on the Qinghai-Tibetan Plateau and its adjacent territories, is one of world’s most remarkable domestic animals. Over the past decades, research has been done on properties of yak meat at physiological and biochemical levels. In recent years, some candidate genes associating with meat quality and lipid metabolism in yak have been studied (MA et al. 2007, ZHONG et al. 2007). The Hormone Sensitive Lipase (LIPE) gene has been regarded as a candidate gene associating with lipid metabolism and meat quality. Several studies have reported the genetic variations in the LIPE genes of human and pig (TALMUD et al. 1998, KNOLL et al. 1998, WU et al. 1998, HARBITZ et al. 1999), whereas the yak LIPE gene polymorphism has not been investigated and no information is available. The aim of this study was to identify and characterize the genetic variation in Chinese yak LIPE at the DNA sequence level and genotyping of the polymorphism within LIPE in different yak breeds.

Engineered Saccharomyces cerevisiae that produces 1,3-propanediol from D-glucose

AIMS

Saccharomyces cerevisiae is a safe micro-organism used in fermentation industry. 1,3-Propanediol is an important chemical widely used in polymer production, but its availability is being restricted owing to its expensively chemical synthesis. The aim of this study is to engineer a S. cerevisiae strain that can produce 1,3-propanediol at low cost.

METHODS AND RESULTS

By using D-glucose as a feedstock, S. cerevisiae could produce glycerol, but not 1,3-propanediol. In this study, we have cloned two genes yqhD and dhaB required for the production of 1,3-propanediol from glycerol, and integrated them into the chromosome of S. cerevisiae W303-1A by Agrobacterium tumefaciens-mediated transformation. Both genes yqhD and dhaB functioned in the engineered S. cerevisiae and led to the production of 1,3-propanediol from D-glucose.

CONCLUSION

Saccharomyces cerevisiae can be engineered to produce 1,3-propanediol from low-cost feedstock D-glucose.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first report on developing S. cerevisiae to produce 1,3-propanediol by using A. tumefaciens-mediated transformation. This study might lead to a safe and cost-efficient method for industrial production of 1,3-propanediol.