Modelling the transmission dynamics of meticillin-resistant Staphylococcus aureus in Beijing Tongren hospital

Semi-professional volunteers work in many tertiary care hospitals in China as healthcare assistants. Proper infection control measures are needed to reduce nosocomial transmission involving volunteers. A compartmental model was constructed to describe the transmission characteristics of meticillin-resistant Staphylococcus aureus (MRSA) in the emergency ward (EW) and respiratory intensive care unit (RICU) for volunteers in Beijing Tongren Hospital, Beijing, China. The model consists of components describing uncolonized and colonized patients, uncontaminated and contaminated healthcare workers (HCWs), and uncontaminated and contaminated volunteers. The basic reproduction number (R(0)) was calculated, and the dependence of R(0) on various model parameters was analysed. Moreover, simulations of the model were performed for comparision with the reported data on the numbers of colonized patients in the EW and RICU from 3 March 2009 to 28 February 2010, respectively. Sensitivity analysis of R(0) showed that increasing handwashing compliance among HCWs and volunteers would reduce the risk of transmission dramatically. As volunteers care for patients on a one-to-one basis, this study showed that the number of MRSA-positive patients would increase if volunteers were replaced by HCWs. Therefore, in addition to improving hand hygiene among HCWs, the employment of properly trained volunteers is an attractive alternative to decrease MRSA and other multi-drug resistant bacteria infections in the hospital setting.

A novel DDX5 gene in the freshwater crayfish Cherax quadricarinatus is highly expressed during ontogenesis and spermatogenesis

The freshwater crayfish Cherax quadricarinatus, originally from Australia, is an invasive species that is also widely used in aquaculture. DEAD-box helicase family genes are found throughout evolution and encode RNA-binding proteins. The human DDX5 (p68) is important for normal cell growth, differentiation and proliferation. We identified a C. quadricarinatus homolog of DDX5 (Cq-DDX5); the temporal expression of Cq-DDX5 mRNA transcripts was measured during early ontogenesis, during spermatogenesis, during testes development, and during the annual cycle. The Cq-DDX5 cDNA comprises 2258 nucleotides, with an open reading frame of 1569 bp, encoding 522 amino acid residues. The deduced amino acid sequence of Cq-DDX5 has a 53 to 90% similarity to DDX5 of other eukaryotic species. mRNA transcripts of Cq-DDX5 were detected in all tissues, with high levels in the gonads. The DDX5 expression was highest in the nauplii stage, during early ontogenesis and during testes development. In adult testes, transcripts appeared at significantly higher levels in the prespawning and spawning phase than in the post-spawning or regressed phase. Eyestalk ablation resulted in upregulation of Cq-DDX5 in adult male gonads in a time-dependent manner, with a peak at about 12 days. We conclude that the Cq-DDX5 gene plays an important role in early ontogenesis and spermatogenesis, with a crucial reproductive function in germ cell differentiation in these invertebrates.

Safety and efficacy of intravitreal injection of recombinant erythropoietin for protection of photoreceptor cells in a rat model of retinal detachment

PURPOSE

To elucidate the safety and efficacy of exogenous erythropoietin (EPO) for the protection of photoreceptor cells in a rat model of retinal detachment (RD).

METHODS

Recombinant rat EPO (400 ng) was injected into the vitreous cavity of normal rats to observe the eye manifestations. Retinal function was assessed by flash electroretinograms. Histopathological examination of retinal tissue was performed at 14 days and 2 months after injection, respectively. To investigate the inhibitory effect of EPO on photoreceptor cell apoptosis in RD rats, 100, 200, or 400 ng EPO was injected into the vitreous cavity immediately after RD model establishment. Apoptosis of photoreceptor cells was determined at 3 days after injection. Caspase-3 activation was measured by western blot analysis and immunofluorescence, respectively, and the level of Bcl-X(L) expression was analyzed by western blot.

RESULTS

Intravitreal injection of EPO 400 ng into normal rats had no significant impact on retinal function, morphology, or structure. Apoptosis of retinal photoreceptor cells apparently increased after RD and was significantly reduced following EPO treatment. The thickness of the outer nuclear layer in the RD + 400 ng group was significantly thicker than that in other experimental RD groups both at 14 days and at 2 months after RD (P < 0.05). Western blot and immunofluorescence analyses showed decreased caspase-3 activation and increased Bcl-X(L) expression following EPO treatment.

CONCLUSION

Intravitreal injection of EPO 400 ng is safe, and EPO may suppress caspase-3 activation and enhance Bcl-X(L) expression, resulting in inhibition of apoptosis and protection of photoreceptor cells.

Association of IL-1β and IL-6 gene polymorphisms with recurrent spontaneous abortion in a Chinese Han population

As certain cytokines may play a role in unexplained recurrent spontaneous abortion (RSA) and also some cytokine gene polymorphisms may affect the level of cytokine production, the aim of this study was to investigate the relationship between Chinese RSA and polymorphisms of the genes coding for interleukin (IL)-1β (-31C/T, -511C/T, +3954C/T) and IL-6 (-634C/G). Women (n = 162) with at least three consecutive spontaneous abortions and 156 ethnically matched healthy women with at least one successful pregnancy were included. Genotypes were determined using restriction fragment length polymorphism analysis of polymerase chain reaction products. No significant differences were found in the IL-1β-31T, -511T and +3954T distributions between the RSA group and the control group. On the other hand, the frequencies of the IL-6-634GG genotype and -634G allele were significantly decreased in the RSA group versus the control group (genotype: P = 0.0003; allele: P = 0.002), suggesting the IL-6-634C/G polymorphism might be a possible genetic protective factor for RSA.

Simple way for achieving passive all-optical switching of continuous waves lasers using pure nematic liquid crystal

We have examined pure nematic liquid crystal (LC), 4'-pentyl-4-biphenylcarbonitrile (5-CB), with a 90° twisted alignment within a cell made of two cross-polarized absorptive plastic polarizers, and investigated the nonlinear transmission properties using cw (532 nm) lasers. We observed optically self-activated polarization switching with a factor of three lower switching power than a dye-doped LC cell with similar linear transmittance using glass substrates. We also studied the dynamics of the switching processes and observed millisecond switching time. These studies have demonstrated a simpler but more efficient way for fabricating broadband, low switching power, millisecond time scale switching, and optical limiting devices.

Ontogeny of the stomach in yellow catfish (Pelteobagrus fulvidraco): detection and quantifictation of pepsinogen and H+/K+ -ATPase gene expression

Yellow catfish (Pelteobagrus fulvidraco) is an important commercial species with high aquaculture potential in China. To better understand the process of digestive functioning of gastric gland development during the larval from 1 dph (day post-hatching) to 30 dph, real-time PCR was used to detect and quantify the pepsinogen and H(+) /K(+) -ATPase gene expression in P. fulvidraco. These data were also compared with the adult situation. The results showed that the expression of pepsinogen and H(+) /K(+) -ATPase genes in P. fulvidraco larvae both started at 1 dph, though the expression level was very low until 3 dph. The quantification of pepsinogen gene expression increased significantly from 4 to 8 dph, increased fluctuantly from 8 to 23 dph and rose sharply from 23 to 30 dph. In comparison with adult fish, there were no significant differences with larvae at 5 and 23 dph. However, data of 10 and 30 dph larvae were obviously higher than those of adult group. H(+) /K(+) -ATPase gene expression increased linearly from 1 to 30 dph. However, it was significantly lower than that of adult. The results show that P. fulvidraco larvae have an earlier functional stomach, though the function of the stomach is still not perfect. There is a gradual acidification environment within the stomach during the P. fulvidraco larvae development. Based on these results, we suggest that the weaning time for P. fulvidraco larvae would be much better after 23 dph.

Brain-derived neurotrophic factor-activated astrocytes produce mechanical allodynia in neuropathic pain

Neuropathic pain management is challenging for physicians and a vexing problem for basic researchers. Recent studies reveal that activated spinal astrocytes may play a vital role in nerve injury-induced neuropathic pain, although the mechanisms are not fully understood. We have found increased glial fibrillary acidic protein (GFAP) expression, a hallmark of reactive gliosis, and elevated brain-derived neurotrophic factor (BDNF) expression in the dorsal horn in a rat model of allodynia induced by spinal nerve ligation (SNL). The high GFAP expression and mechanical allodynia that SNL induces were prevented by the intrathecal injection of the BDNF-sequestering fusion protein TrkB/Fc. Additionally, mechanical allodynia and GFAP overexpression was induced by the spinal administration of exogenous BDNF to naive rats, and exogenous BDNF given together with fluorocitrate, an astrocytic metabolism inhibitor, inhibited allodynia and GFAP upregulation. Exogenous BDNF also activated the astrocytes directly when tested in vitro. Furthermore, intrathecal administration of BDNF-stimulated astrocytes also induced mechanical allodynia in naive rats. All of these results indicate that astrocytes activated by BDNF might contribute to mechanical allodynia development in neuropathic pain in rats.

Transverse spin current in the s-wave/p-wave Josephson junction

We report a theoretical study on spin transport in the hybrid Josephson junction composed of singlet s-wave and triplet p-wave superconductor. The node of the triplet pair potential is considered perpendicular to the interface of the junction. Based on a symmetry analysis, we predict that there is no net spin density at the interface of the junction but instead a transverse mode-resolved spin density can exist and a nonzero spin current can flow transversely along the interface of the junction. The predictions are numerically demonstrated by means of the lattice Matsubara Green's function method. It is also shown that, when a normal metal is sandwiched in between two superconductors, both spin current and transverse mode-resolved spin density are only residing at two interfaces due to the smearing effect of the multimode transport. Our findings are useful for identifying the pairing symmetry of the p-wave superconductor and generating spin current.

Effect of downregulated β-catenin on cell proliferative activity, the sensitivity to chemotherapy drug and tumorigenicity of ovarian cancer cells

The role of Wnt/β-catenin signaling pathway in the etiology and/or progression of ovarian cancer has been well documented. It was demonstrated that ovarian cancer constantly exhibit constitutive activation of canonical Wnt signaling, usually as a result of oncogenic mutations that stabilize and dysregulate the β-catenin protein. In this study, we transfected an expression vector-based small hairpin RNA (shRNA) targeting to β-catenin encoding gene into human A2780 ovarian cancer cells to investigate the effects of β-catenin knockdown on biological characteristics of ovarian cancer cells. The results showed that β-catenin shRNA expression resulted in decreased β-catenin mRNA and protein expression in the transfected A2780 cells, inhibition of cellular proliferation, decreased capability of clonogenicity in the plating and the soft agar, and increased sensitivities to chemotherapy drugs vincristine, paclitaxel and cisplatin compared to untransfected cells. Importantly, we found that shRNA-mediated knockdown of β-catenin strongly decreases tumour growth of human A2780 ovarian cancer cells in xenografts. These results demonstrate that β-catenin might be an effective therapeutic target for human ovarian cancer treatment.

Genetic diversity of Tibetan goats of Plateau type using microsatellite markers

Abstract. The 10 microsatellite markers (XBM7, XBM11, XBM16, XBM19, XBM24, XBM31, XBM84, TGLA53, SRCRSP-10 and ILS005) were selected to investigate the genetic diversity of Tibetan goat of Plateau type (NM, n=108), and the other 5 goat populations, i.e., Tibetan goat of Valley type (TG, n=36), Baiyu black goat (BY, n=36), Jianchang black goat (JC, n=36), Meigu goat (MG, n=36) and Xinjiang goat (XJ, n=32) were served as control. The mean polymorphism information content, heterozygosity and effective allele number of these 6 populations were 0.660/0.777/4.476, 0.716/0.797/4.9416, 0.631/0.673/3.061, 0.649/0.680/3.125, 0.629/0.680/3.125 and 0.561/0.793/4.840 respectively. The allele frequencies of Tibetan goat of plateau type in 10 microsatellite loci were greatly different with other 5 goat populations. The 6 goat populations were grouped into three distinct clusters: the Tibetan goat cluster (NM goat and TG goat), Sichuan goat cluster (JC goat, MG goat and BY goat), and Xinjiang goat cluster (XJ goat). These 3 distinct clusters were finally clustered together. The genetic differences among populations were in accordance with their geographical and historical origins.

MicroRNA-mediated breast cancer metastasis: from primary site to distant organs

The recent upsurge of interest in microRNA (miRNA) is partly attributed to the discovery of the novel roles of miRNAs in many physiological and pathological processes, including tumor development. Research on breast cancer metastasis has also focused on the concept of miRNA, which can act either as promoters or as suppressors of metastases. This review will focus on a series of recent studies that demonstrate the involvement of miRNAs in breast cancer metastasis and will briefly describe various pathways of miRNA-regulated metastasis. Finally, future prospects will be discussed for the potential role of miRNAs as predictive markers and therapeutic agents for patients with breast cancer metastases.

Detection of three human adenovirus species in adults with acute respiratory infection in China

Human adenoviruses (HAdVs) are recognized as causal agents in a wide range of human diseases. However, researchers lack sufficient data on the exact HAdV species and serotypes associated with adult acute respiratory tract infections (ARTIs). To detect and characterize HAdV infections in adults in China, clinical specimens were collected from 10,310 adults with ARTIs from May 2005 to July 2010. The partial HAdV hexon gene was amplified by polymerase chain reaction (PCR), sequenced, and phylogenetically analyzed. HAdVs were detected in 86 samples (0.8%), of which 67 (77.9%) were species B (HAdV-3, -7, -11, and -14), 7 (8.1%) were species C (HAdV-1, -2, and -6), and 12 (14%) were species E (HAdV-4). HAdV-3 was the most frequently detected serotype (41/86, 47.7%), followed by HAdV-7 (13/86, 15.1%), HAdV-4 (12/86, 14.0%), and HAdV-11 (11/86, 12.8%). Patients 14-25 years old (60.5%) exhibited a higher rate of adenovirus detection than older patients. Co-infections with other respiratory viruses were observed in samples positive for HAdV species B and E. Human rhinovirus was the most commonly found virus in patients with HAdV infection. These findings provide baseline data for the surveillance and control of HAdV infection in China.