Molecular Modeling-Based Inclusion Mechanism and Stability Studies of Doxycycline and Hydroxypropyl-β-Cyclodextrin Complex for Ophthalmic Delivery

The aim of the present study was to prepare a stable complex of doxycycline (Doxy) and hydroxypropyl-β-cyclodextrin (HPβCD) for ophthalmic delivery and investigate the inclusion mechanism and the inclusion effects on the stability of Doxy. The Doxy/HPβCD complex was prepared by solution stirring and then characterized by scanning electron microscopy and ultraviolet spectroscopy. Based on results of nuclear magnetic resonance, molecular model of Doxy/HPβCD complex was established using computational simulation of PM3 method implemented in Gaussian 03. Stabilities of Doxy/HPβCD complex in both aqueous solution and solid state at 25°C were evaluated by HPLC. Finally, in vitro antibacterial activity of the Doxy/HPβCD complex was evaluated by disk diffusion test. It was found that the stabilities of Doxy/HPβCD complex in both aqueous solution and solid state were improved obviously as compared with Doxy alone. This stability enhancement is consistent with the inclusion mechanism between HPβCD and Doxy, which showed that the unstable site of Doxy molecule at 6-CH₃ was protected in the hydrophobic cavity of HPβCD, additionally, the chelation of Mg²⁺ provided a synergetic protection of the other unstable site of Doxy at 4-N(CH₃)₂. The antibacterial activity results indicated that Doxy/HPβCD complex might have potential for clinical applications.     

hPNAS-4 inhibits proliferation through S phase arrest and apoptosis: underlying action mechanism in ovarian cancer cells

PNAS-4, a novel pro-apoptotic gene, was activated during the early response to DNA damage. Previous studies have shown that hPNAS-4 can inhibit tumor growth when over-expressed in ovarian cancer cells. However, the underlying action mechanism remains elusive. In this work, we found that hPNAS-4 expression was significantly increased in SKOV3 cells when exposed to cisplatin, methyl methanesulfonate or mitomycin C, and that its overexpression could induce proliferation inhibition, S phase arrest and apoptosis in A2780s and SKOV3 ovarian cancer cells. The S phase arrest caused by hPNAS-4 was associated with up-regulation of p21. p21 is p53-dispensable and correlates with activation of ERK, and activation of the Cdc25A-Cdk2-Cyclin E/Cyclin A pathway, while the pro-apoptotic effects of hPNAS-4 were mediated by activation of caspase-9 and -3 other than caspase-8, and accompanied by release of AIF, Smac and cytochrome c into the cytosol. Taken together, these data suggest a new mechanism by which hPNAS-4 inhibits proliferation of ovarian cancer cells by inducing S phase arrest and apoptosis via activation of Cdc25A-Cdk2-Cyclin E/Cyclin A axis and mitochondrial dysfunction-mediated caspase-dependent and -independent apoptotic pathways. To our knowledge, we provide the first molecular evidence for the potential application of hPNAS-4 as a novel target in ovarian cancer gene therapy.     

Inhibition of hydrogen sulfide synthesis provides protection for severe acute pancreatitis rats via apoptosis pathway

We aimed to investigate the relationship between the synthesis of hydrogen sulfide (H₂S) and the pancreatic acinar cell apoptosis in severe acute pancreatitis (SAP) rats, as well as analyse the potential apoptotic pathway involved in this process. Sixty rats had been equally divided into four groups: sham, SAP, SAP + sodium hydrosulfide (NaHS) and SAP + DL-propargylglycine (PAG). 24 h after SAP induction, all surviving animals of each group were sacrificed to collect blood and tissue samples for the following measurements: the level of serum H₂S as well as the levels of tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), H₂S synthesizing activity, CSE mRNA and protein expression, maleic dialdehyde (MDA) and myeloperoxidase (MPO) activity, the expression of Bax, Bcl-2, caspase-3, -8 and -9, the release of cytochrome c and the activation of nuclear factor-kappa B (NF-κB), ERK1/2, JNK1/2 and p38 in pancreas. Furthermore, in situ detection of cell apoptosis was examined and the severity of pancreatic damage was analyzed by pathological grading and scoring. Results Significant differences in every index except IL-10 had been found between the SAP, NaHS and PAG groups (P < 0.05). Treatment with PAG obviously induced the pancreatic acinar cell apoptosis as well as improved all the pathological changes and inflammatory parameters. In contrast, administration of NaHS significantly attenuated apoptosis in the pancreas and aggravated the severity of pancreatic damage. Moreover, the expressions of caspase-3, -8, -9 and the release of cytochrome c were all increased in the apoptotic cells, and the activity of NF-κB as well as the phosphorylation of ERK1/2, JNK1/2 and p38 decreased accompanying with the reduction of the serum H₂S level. H₂S plays a pivotal role in the regulation of pancreatic acinar cell apoptosis in SAP rats. The present results showed that inhibition of H₂S synthesis provided protection for SAP rats via inducing acinar cell apoptosis. This process acted through both extrinsic and intrinsic apoptotic pathways, and may be regulated by reducing the activity of NF-κB.     

VRAA: virtualized resource auction and allocation based on incentive and penalty

Virtualization is widely used in cloud computing environments to efficiently manage resources, but it also raises several challenges. One of them is the fairness issue of resource allocation among virtual machines. Traditional virtualized resource allocation approaches distribute physical resources equally without taking into account the actual workload of each virtual machine and thus often leads to wasting. In this paper, we propose a virtualized resource auction and allocation model (VRAA) based on incentive and penalty to correct this wasting problem. In our approach, we use Nash equilibrium of cooperative games to fairly allocate resources among multiple virtual machines to maximize revenue of the system. To illustrate the effectiveness of the proposed approach, we then apply the basic laws of auction gaming to investigate how CPU allocation and contention can affect applications’ performance (i.e., response time), and its effect on CPU utilization. We find that in our VRAA model, the fairness index is high, and the resource allocation is closely proportional to the actual workloads of the virtual machines, so the wasting of resources is reduced. Experiment results show that our model is general, and can be applied to other virtualized non-CPU resources.     

ORTHRUS: a lightweighted block-level cloud storage system

Taking advantage of distributed storage technology and virtualization technology, cloud storage systems provide virtual machine clients customizable storage service. They can be divided into two types: distributed file system and block level storage system. There are two disadvantages in existing block level storage system: Firstly, Some of them are tightly coupled with their cloud computing environments. As a result, it’s hard to extend them to support other cloud computing platforms; Secondly, The bottleneck of volume server seriously affects the performance and reliability of the whole system. In this paper we present a lightweighted block-level storage system for clouds—ORTHRUS, based on virtualization technology. We first design the architecture with multiple volume servers and its workflows, which can improve system performance and avoid the problem. Secondly, we propose a Listen-Detect-Switch mechanism for ORTHRUS to deal with contingent volume servers’ failure. At last we design a strategy that dynamically balances load between multiple volume servers. We characterize machine capability and load quantity with black box model, and implement the dynamic load balance strategy which is based on genetic algorithm. Extensive experimental results show that the aggregated I/O throughputs of ORTHRUS are significantly improved (approximately two times of that in Orthrus), and both I/O throughputs and IOPS are also remarkably improved (about 1.8 and 1.2 times, respectively) by our dynamic load balance strategy.     

Effect of the primary host for production of both sexes on the mating interaction in an autoparasitoid species

Encarsia sophia (Girault and Dodd) is an autoparasitoid in the hymenopteran family Aphelinidae. The females develop as primary parasitoids on whitefly nymphs (primary hosts), whereas the males develop as hyperparasitoids on their own species or on other primary parasitoid species (secondary hosts). The autoparasitoids not only parasitise whiteflies but also kill them with strong host-feeding capacity. In this study, female and male E. sophia were reared on the primary hosts Trialeurodes vaporariorum and Bemisia tabaci ‘Q’, and the host-feeding and parasitism of wasps on both whitefly species were determined for the four possible different mating combinations: (i) E. sophia females reared on B. tabaci (ESF-BT) mated with E. sophia males from B. tabaci (ESM-BT), (ii) E. sophia females reared on T. vaporariorum (ESF-TV) mated with E. sophia males from T. vaporariorum (ESM-TV), (iii) ESF-BT mated with ESM-TV, and (iv) ESF-TV mated with ESM-BT. ESF-TV mated with ESM-TV killed the largest percentage of whitefly nymphs through host feeding. The ESF-TV with larger body size mating with larger ESM-TV killed more whitefly nymphs through host feeding than those mating with smaller ESM-BT. Whether B. tabaci or T. vaporariorum were used as hosts, ESF-TV mated with ESM-TV and ESM-BT and ESF-BT mated with ESM-BT significantly parasitised more whitefly nymphs than ESF-BT mated with ESM-TV. In general, ESF-BT mated with ESM-TV killed significantly fewer whitefly nymphs through parasitism and host feeding than the other three mating combinations on both whitefly species. These results indicated that the performance of autoparasitoids on insect pests was not only dependent on females but was also affected by mating with males from different primary host species.     

Subtype Identification in Acutely Dissociated Rat Nodose Ganglion Neurons Based on Morphologic Parameters

Nodose ganglia are composed of A-, Ah- and C-type neurons. Despite their important roles in regulating visceral afferent function, including cardiovascular, pulmonary, and gastrointestinal homeostasis, information about subtype-specific expression, molecular identity, and function of individual ion transporting proteins is scarce. Although experiments utilizing the sliced ganglion preparation have provided valuable insights into the electrophysiological properties of nodose ganglion neuron subtypes, detailed characterization of their electrical phenotypes will require measurements in isolated cells. One major unresolved problem, however, is the difficulty to unambiguously identify the subtype of isolated nodose ganglion neurons without current-clamp recording, because the magnitude of conduction velocity in the corresponding afferent fiber, a reliable marker to discriminate subtypes in situ, can no longer be determined. Here, we present data supporting the notion that application of an algorithm regarding to microscopic structural characteristics, such as neuron shape evaluated by the ratio between shortest and longest axis, neuron surface characteristics, like membrane roughness, and axon attachment, enables specific and sensitive subtype identification of acutely dissociated rat nodose ganglion neurons, by which the accuracy of identification is further validated by electrophysiological markers and overall positive predictive rates is 89.26% (90.04%, 76.47%, and 98.21% for A-, Ah, and C-type, respectively). This approach should aid in gaining insight into the molecular correlates underlying phenotypic heterogeneity of nodose ganglia. Additionally, several critical points that help for neuron identification and afferent conduction calibration are also discussed.     

Pre-induced adult human peripheral blood mononuclear cells migrate widely into the degenerative retinas of rd1 mice

Background aimsRecent advances in stem cell research have raised the possibility of stem cells repairing or replacing retinal photoreceptor cells that are either dysfunctional or lost in many retinal diseases. Various types of stem cells have been used to replace retinal photoreceptor cells. Recently, peripheral blood stem cells, a small proportion of pluripotent stem cells, have been reported to mainly exist in the peripheral blood mononuclear cells (PBMCs).MethodsIn this study, the effects of pre-induced adult human PBMCs (hPBMCs) on the degenerative retinas of rd1 mice were investigated. Freshly isolated adult hPBMCs were pre-induced with the use of the conditioned medium of rat retinas for 4 days and were then labeled with chloromethyl-benzamidodialkylcarbocyanine (CM-DiI) and then transplanted into the subretinal space of the right eye of rd1 mice through a trans-scleral approach. The right eyes were collected 30 days after transplantation. The survival and migration of the transplanted cells in host retinas were investigated by whole-mount retinas, retinal frozen sections and immunofluorescent staining.ResultsAfter subretinal transplantation, pre-induced hPBMCs were able to survive and widely migrate into the retinas of rd1 mice. A few CM-DiI–labeled cells migrated into the inner nuclear layer and the retinal ganglion cell layer. Some transplanted cells in the subretinal space of rd1 host mice expressed the human photoreceptor–specific marker rhodopsin.ConclusionsThis study suggests that pre-induced hPBMCs may be a potential cell source of cell replacement therapy for retinal degenerative diseases.