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The differentiation and response of CD8+ T cells is vital in host defense against human immunodeficiency virus type 1 (HIV-1). MicroRNA (miR)-155 is an important regulator of T cell differentiation. However, the profile of miR-155 in HIV-1 infected individuals and its association with CD8+ T cell differentiation remain to be fully elucidated. The present cross-sectional study was performed involving 63 HIV-1-infected patients undergoing highly active antiretroviral therapy (HAART), 31 HAART-naïve patients and 35 healthy controls. The levels of miR-155 in CD8+ T cells were detected using reverse transcription-quantitative polymerase chain reaction analysis. Subsets of CD8+ T cell differentiation were detected using flow cytometry. The results revealed that the discord controllers and HAART-naïve patients showed higher percentages of effector and effector memory cells, and lower percentages of naïve cells (P<0.05). The levels of miR-155 in CD8+ T cells from the HIV-1-infected patients were higher, particularly in the discord controllers and HAART naïve patients (P<0.01). The expression levels of miR-155 were positively correlated with the percentages of effector and effector memory CD8+ T cells, and negatively correlated with the percentages of naïve and central memory CD8+ T cells (P<0.01). Taken together, these findings suggested that the levels of miR-155 in CD8+ T cells of patients with HIV-1 were increased and associated with CD8+ T cell differentiation. [ABSTRACT FROM AUTHOR]

Macrophages are major targets of human immunodeficiency virus (HIV) and can act as long-term reservoirs of the virus. Chronic HIV-1 infection is associated with dysregulated inflammation. Recepteur d'origine nantais (RON) is expressed in tissue resident macrophages and functions to maintain inflammatory homeostasis. The present study aimed to compare the expression of RON on HIV-positive and - negative participants, and to investigate the mechanism by which HIV-1 influences the expression and function of RON in the JLTRG T cell line. The levels of RON and the RON ligand, macrophage-stimulating protein (MSP), in the peripheral blood of HIV-1-positive patients that were receiving (n=22) or not receiving highly active anti-retroviral therapy (HAART) (n=82) and 37 healthy control participants were determined by enzyme-linked immunosorbent assay. Expression of RON and MSP in the JLTRG T cell line was assessed by western blotting and the subcellular location was analyzed by fluorescence microscopy. JLTRG cells were co-cultured with a cell line that stably expresses HIV, H9/HTLV-IIIB, and alterations in the levels of RON and nuclear factor-κB (NF-κB) in JLTRG cells were assessed by western blotting. The expression of RON and MSP were significantly different in the serum of HIV-1- positive patients that were receiving HAART compared with those not receiving H AART (P<0.05) a nd healthy control patients (P<0.01). RON was detected in JLTRG cells, and was shown to be downregulated by HIV-1 infection. HIV-1 infection of JLTRG cells also reduced NF-κB phosphorylation. Thus, HIV-1 was shown to downregulate the expression and phosphorylation of RON by targeting the NF-κB pathway. [ABSTRACT FROM AUTHOR]

We assessed a colloidal gold immunochromatographic assay (GICA) for rapid detection of influenza A (H7N9) and compared it with reverse-transcription-polymerase chain reaction (RT-PCR) and viral culture. Samples from 35 H7N9 infected patients were collected, including 45 throat swab samples, 56 sputum samples, and 39 feces samples. All samples were tested by GICA, viral culture, and RT-PCR. GICA specifically reacted with recombinant HA proteins, virus lysates, and clinical samples fromH7 subtype viruses. Compared with RT-PCR, GICA demonstrated low sensitivity (33.33%) but high specificity (97.56%). The positive rate of GICA tests for samples collected in the period from 8 to 21 days after contact with poultry was much higher than those for samples collected before or after this period. Compared with viral culture, GICA showed sensitivity of 91.67% and specificity of 82.03%. Sputum specimens weremore likely to test positive for H7N9 virus than samples from throat swabs and feces. The GICA-based H7 test is a reliable, rapid, and convenient method for the screening and diagnosis of influenza A (H7N9) disease, especially for the sputum specimens with high viral load. It may be helpful in managing H7N9 epidemics and preliminary diagnosis in early stages in resource-limited settings. [ABSTRACT FROM AUTHOR]

Objective: The aims of this study were to systematically review epidemiological characteristics in older people living with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) (PLWHA) in low endemic areas of the People's Republic of China, analyze the causes of death and mortality, and provide a basis for targeted prevention in these populations. Methods: Nine counties representative of the distribution and epidemiological factors of the HIV epidemic in Zhejiang Province were selected, and data from 1,115 HIV-positive individuals, including 196 older people (⩾50 years), who were confirmed as PLWHA from January 1, 2000 to December 31, 2012, were retrospectively analyzed. Results: The proportion of older PLWHA increased from 0% in 2000 to 22.45% in 2012. Sexual transmission was the main route, accounting for 82.65% of infections in this group. Compared with the younger group (range from 14 to 49 years old), the older group had significantly lower CD4+ cell counts (291.64 versus 363.63; P<0.001) when first diagnosed, and more of this group presented in the AIDS state with opportunistic infections (51.02% versus 34.06%; P<0.001). In the older group, 25 (12.76%) patients died directly of AIDS and 171 (87.24%) were censored, and in the younger group 50 (5.44%) patients died directly of AIDS and 869 (94.56%) were censored. Estimated survival time since HIV diagnosis in the older group was 11.54±0.49 years (95% confidence interval [CI] 10.59-12.50), while in the younger group it was 13.85±0.46 years (95% CI 12.94-14.76), the log rank (Mantel-Cox) test gave a chi-square value of 3.83, and there was significant difference between the groups (P<0.05). Conclusion: The number of older PLWHA increased steadily over the study period in low HIV endemic provinces of a developing country. Later discovery and preexisting disease perhaps contributed to a shorter estimated survival time for older PLWHA and higher mortality. [ABSTRACT FROM AUTHOR]

Objective: The development of a human immunodeficiency virus (HIV)-1 promoter reporter system is critical for investigating transcription activity of the virus. We designed a modified overlap extension PCR method for single round site-directed mutagenesis of the long terminal repeat (LTR) segment of HIV-1. Methods: The procedure consists of overlap extension PCR, DpnI digestion, and product transformation. Wild-type and serial sequence deletion clones of HIV-1 LTR were constructed. βasal transcription activity was also measured. Results: The overall efficiency for obtaining the desired products was 53.2%. The reporter assay indicated the importance of the second NF-κβ cis-element and surrounding regions in mediating the regulation of HIV-1 transcription. Conclusion: The technique we investigated is suitable for highthroughput functional studies of virus-host interaction. [ABSTRACT FROM AUTHOR]

Significant links exist between the sulfur cycle, sulfur geochemistry of sedimentary systems, and ore deposits over the course of Earth history. A picture emerges of an Archean and Paleoproterozoic stage of the sulfur cycle that has much lower levels of sulfate (<200 µM), carries a signal of mass-independent sulfur, and preserves evidence for temporal and spatial heterogeneity that reflects lower amounts of sulfur cycling than today. A second stage of ocean chemistry in the Paleoproterozoic, with higher atmospheric oxygen and oceanic sulfate at low millimolar levels, follows this stage. The isotopic record in sedimentary rocks and in sulfide-bearing ore deposits suggests abundant pyrite burial and implies a missing 34S-depleted pool that may have been lost via deep ocean deposition and possibly subduction. Proterozoic ocean chemistry appears to be quite complex. The surface waters of the Proterozoic oceans are believed to have been oxygenated, but geologic evidence from ore deposits and sedimentary rocks supports coexistence of significant anoxic, intermediate water and deep-water pools in the Mesoproterozoic. This stage in ocean chemistry ends with the second major global oxidation event in the latest Neoproterozoic (~600 Ma). This event started the transition to more oxygenated intermediate and deep waters, and higher but variable oceanic sulfate concentrations. The event set the scene for the formation in the Phanerozoic of the first significant MVT deposits and possibly is reflected in changes in other sedimentary rock-hosted base metal sulfide deposits. [ABSTRACT FROM AUTHOR]

Cortical dysplasia (CD), a frequent pathological substrate of pediatric epilepsy surgery patients, has a number of similarities with immature cortex, such as reduced Mg2+ sensitivity of N-methyl-D-aspartate (NMDA) receptors and the persistence of subplate-like neurons and undifferentiated cells. Because γ-aminobutyric acid (GABA) is the main neurotransmitter in early cortical development, we hypothesized increased GABA receptor-mediated synaptic function in CD tissue. Infrared videomicroscopy and whole-cell patch clamp recordings were used to characterize the morphology and electrophysiological properties of immature and normal-appearing neurons in slices from cortical tissue samples resected for the treatment of pharmacoresistant epilepsy in children (0.2–14 years). In addition, we examined spontaneous and evoked synaptic activity, as well as responses to exogenous GABA application. We demonstrate both the presence of immature pyramidal neurons and networks in young CD tissue and the predominance of GABA synaptic activity. In addition, spontaneous GABA depolarizations frequently induced action potentials, supporting a potential excitatory role of GABA in CD. Evoked synaptic responses mediated by GABA were also prominent, and bath application of 4-aminopyridine induced rhythmic depolarizations that were blocked by bicuculline. Finally, responses to exogenous application of GABA had depolarized reversal potentials in severe compared to mild and non-CD cases. The present data support the hypothesis that CD shares features of immature cortex, with predominant and potentially excitatory GABAA receptor-mediated neurotransmission. These results could partially explain the increased excitability of the cortical network in pediatric CD. [ABSTRACT FROM AUTHOR]

Dopamine (DA) modulates glutamate neurotransmission in the striatum. Abnormal DA modulation has been implicated in neurological and psychiatric disorders. The development of DA transporter knock-down (DAT-KD) mice has permitted modeling of these disorders and has shed new light on DA modulation. DAT-KD mice exhibit increased extracellular DA, hyperactivity, and alterations in habituation. We used whole cell patch-clamp recordings from visually identified striatal neurons in slices to examine the effects of DAT-KD on corticostriatal transmission. Electrophysiological recordings from medium-sized spiny neurons in the dorsal striatum revealed alterations in both amplitude and frequency, of spontaneous glutamate receptor-mediated synaptic currents in cells from DAT-KD mice. Furthermore, kinetic analyses revealed that these currents had shorter half-amplitude durations and faster decay times. In contrast, GABA-receptor–mediated synaptic currents were not altered. Striatal neurons from DAT-KD mice also responded differently to amphetamine, cocaine, and DA D2-receptor agonists or antagonists compared with wildtype (WT) littermate controls. In WTs amphetamine and cocaine reduced the frequency of spontaneous glutamate currents and these effects appeared to be mediated by activation of D2 receptors. In contrast, in DAT-KD mice either no changes or only small increases in frequency occurred. D2-receptor agonists or antagonists also had opposing effects in WT and DAT-KD mice. Together, these results indicate that chronically increased extracellular DA produces long-lasting changes in corticostriatal communication that may be mediated by changes in D2-receptor function. These findings have implications for understanding mechanisms underlying attention deficit hyperactivity disorder and Tourette's syndrome and may provide insights into novel therapeutic approaches. [ABSTRACT FROM AUTHOR]

Trigeminal motoneurons relay the final output signals generated within the oral-motor pattern generating circuit(s) to muscles for execution of various motor patterns. In recent years, these motoneurons were shown to possess voltage dependent nonlinear membrane properties that allow them to actively participate in sculpting their final output. A complete understanding of the factors controlling trigeminal motoneuronal (TMN) discharge during oral-motor activity requires, at a minimum, a detailed understanding of the palette of ion channels responsible for membrane excitability and a determination of whether these ion channels are targets for modulation. Toward that end, we studied in detail the properties of calcium channels in TMNs and their susceptibility to modulation by 5-HT in rat brain slices. We found that based on pharmacological and voltage-dependent properties, high-voltage-activated (HVA) N-type [ω-conotoxin GVIA (ω-CgTX)]-sensitive, and to a lesser extent P/Q-type [ω-agatoxin IVA (ω-Aga IVA)]-sensitive, calcium channels make up the majority of the whole cell calcium current. 5-HT (5.0 μM) decreased HVA current by 31.3 ± 2.2%, and the majority of this suppression resulted from reduction of current flow through N- and P/Q-type calcium channels. In contrast, 5-HT had no effect on low-voltage-activated (LVA) current amplitude in TMNs. HVA calcium current inhibition was mimicked by 5-CT, a 5-HT1 receptor agonist, and by R(+)-8-hydroxydipropylaminotetralin hydrobromide (8-OH-DPAT), a specific 5-HT1A agonist. The effects of 5-HT were blocked by the 5-HT1A antagonist 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine hydrobromide (NAN-190) but not by ketanserin, a 5-HT2/1C antagonist. Under current clamp, ω-CgTX and 5-HT were most effective in suppressing the mAHP and both increased the spike frequency and input/output gain in response to current injection. Calcium current modulation by 5-HT1A receptors likely is an important mechanism to fine tune the input/output gain of TMNs in response to small incoming synaptic inputs and accounts for some of the previously reported effects of 5-HT on TMN excitability during tonic and burst activity during oral-motor behavior. [ABSTRACT FROM AUTHOR]

The functional and biophysical properties of a persistent sodium current (I(NaP)) previously proposed to participate in the generation of subthreshold oscillations and burst discharge in mesencephalic trigeminal sensory neurons (Mes V) were investigated in brain stem slices (rats, p7-p12) using whole cell patch-clamp methods. I(NaP) activated around -76 mV and peaked at -48 mV, with V1/2 of -58.7 mV. Ramp voltage-clamp protocols showed that I(NaP) undergoes time- as well as voltage-dependent inactivation and recovery from inactivation in the range of several seconds (tau(onset) = 2.04 s, tau(recov) = 2.21 s). Riluzole (< or =5 microM) substantially reduced I(NaP), membrane resonance, postinhibitory rebound (PIR), and subthreshold oscillations, and completely blocked bursting, but produced modest effects on the fast transient Na+ current (I(NaT)). Before complete cessation, burst cycle duration was increased substantially, while modest and inconsistent changes in burst duration were observed. The properties of the I(NaT) were obtained and revealed that the amplitude and voltage dependence of the resulting "window current" were not consistent with those of the observed I(NaP) recorded in the same neurons. This suggests an additional mechanism for the origin of I(NaP). A neuronal model was constructed using Hodgkin-Huxley parameters obtained experimentally for Na+ and K+ currents that simulated the experimentally observed membrane resonance, subthreshold oscillations, bursting, and PIR. Alterations in the model g(NaP) parameters indicate that I(NaP) is critical for control of subthreshold and suprathreshold Mes V neuron membrane excitability and burst generation. [ABSTRACT FROM AUTHOR]

Tropical oceans are the main global water vapor and latent heat sources, but their responses to radiative forcing remain unclear. Here, we investigate oceanic moisture dynamics of the western tropical Pacific (WTP) over the past 210,000 years through an approach of planktonic foraminiferal triple oxygen isotope (Δ′17O). The Δ′17O record is dominated by the precession cycles (~23,000 years), with lower values reflecting higher humidity in concert with higher Northern Hemisphere summer insolation. Our empirical and modeling results, combined with other geological archives, suggest that the enhanced moisture convergence over the WTP largely intensifies changes in the meridional and zonal hydrological cycles, affecting rainfall patterns in East Asia and northern South America. We propose that the insolation-driven WTP moisture dynamics play a pivotal role in regulating tropical hydroclimate. [ABSTRACT FROM AUTHOR]

An abstract of the article "Development of Striatal Fast-Spiking GABAergic Interneurons," by Marie-Françoise Chesselet and colleagues is presented.

Purine nucleoside phosphorylase (PNP) enables the breakdown and recycling of guanine nucleosides. PNP insufficiency in humans is paradoxically associated with both immunodeficiency and autoimmunity, but the mechanistic basis for these outcomes is incompletely understood. Here, we identify two immune lineage-dependent consequences of PNP inactivation dictated by distinct gene interactions. During T cell development, PNP inactivation is synthetically lethal with downregulation of the dNTP triphosphohydrolase SAMHD1. This interaction requires deoxycytidine kinase activity and is antagonized by microenvironmental deoxycytidine. In B lymphocytes and macrophages, PNP regulates Toll-like receptor 7 signaling by controlling the levels of its (deoxy)guanosine nucleoside ligands. Overriding this regulatory mechanism promotes germinal center formation in the absence of exogenous antigen and accelerates disease in a mouse model of autoimmunity. This work reveals that one purine metabolism gene protects against immunodeficiency and autoimmunity via independent mechanisms operating in distinct immune lineages and identifies PNP as a potentially novel metabolic immune checkpoint. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) is almost uniformly fatal; however, some improvement in overall survival has been achieved with the introduction of nanocarriers that deliver irinotecan or paclitaxel. Although it is generally assumed that nanocarriers rely principally on abnormal leaky vasculature for tumor access, a transcytosis transport pathway that is regulated by neuropilin-1 (NRP-1) has recently been reported. NRP-1-mediated transport can be triggered by the cyclic tumor-penetrating peptide iRGD. In a KRAS-induced orthotopic PDAC model, coadministration of iRGD enhanced the uptake of an irinotecan-loaded silicasome carrier that comprises lipid bilayer-coated mesoporous silica nanoparticles (MSNPs); this uptake resulted in enhanced survival and markedly reduced metastasis. Further, ultrastructural imaging of the treated tumors revealed that iRGD coadministration induced a vesicular transport pathway that carried Au-labeled silicacomes from the blood vessel lumen to a perinuclear site within cancer cells. iRGD-mediated enhancement of silicasome uptake was also observed in patient-derived xenografts, commensurate with the level of NRP-1 expression on tumor blood vessels. These results demonstrate that iRGD enhances the efficacy of irinotecan-loaded silicasome-based therapy and may be a suitable adjuvant in nanoparticle-based treatments for PDAC. [ABSTRACT FROM AUTHOR]

Background: Co-infection of hepatitis virus is common in human immunodeficiency virus (HIV) infected adults in China. But little is known about hepatitis virus co-infection in pediatric HIV-infected subjects. The study aimed to investigate the impact of hepatitis B virus (HBV) and/or hepatitis C virus (HCV) co-infection and highly active antiretroviral therapy (HAART) on liver function of pediatric HIV-infected subjects. Materials and Methods: A cohort study including 101 pediatric HIV-infected subjects with HBV/HCV co-infection and 44 pediatric comparators with HIV mono-infection was carried out in Henan Province of China from September 2011 to September 2012. All patients received HAART for 1-year. HBV and HCV infection was determined by antibody tests. HIV RNA load, CD4+ T-cell counts and liver function were determined before and after HAART. The Student's t-test or a one-way ANOVA was used for normally distributed values and A Mann-Whitney U-test was performed for values without normal distribution using SPSS statistical package 18.0 (SPSS Inc.). Results: After HAART for 1-year, the median levels of viral load were decreased to lower limit of detection in 90.34% pediatric HIV-infected subjects with/without HBV/HCV co-infection (P < 0.001), and CD4+ T-cell counts increased significantly (P < 0.001). Compared with the pre-HAART, mean level of alanine aminotransferase (ALT) in each group had a significant increase after HAART (P < 0.01). The mean levels of ALT and aspartate aminotransferase (AST) in nevirapine (NVP) based HAART group increased significantly after HAART (P < 0.01). Mean change values of ALT and AST were significantly higher in the NVP based regimen group than in the efavirenz (EFV) based regimen group (P < 0.01). For HIV/ HBV/HCV co-infected patients, mean change values of ALT and AST in NVP-based HAART group was significantly higher than that in EF V-based HAART group (P < 0.01). Conclusion: Highly active antiretroviral therapy can damage liver function in pediatric HIV-infected subjects, especially in those with HBV/HCV co-infection. NVP was more harmful to liver function of pediatric HIV-infected subjects than EFV. [ABSTRACT FROM AUTHOR]

Domestic ducks are natural reservoirs of avian influenza viruses and serve as reassortant hosts for new virus subtypes. We isolated 2 novel influenza A(H5N8) viruses from domestic ducks in eastern China, sequenced their genomes, and tested their pathogenicity in chickens and mice. Circulation of these viruses may pose health risks for humans. [ABSTRACT FROM AUTHOR]

Summary Background Human infection with avian influenza A H7N9 virus emerged in eastern China in February, 2013, and has been associated with exposure to poultry. We report the clinical and microbiological features of patients infected with influenza A H7N9 virus and compare genomic features of the human virus with those of the virus in market poultry in Zhejiang, China. Methods Between March 7 and April 8, 2013, we included hospital inpatients if they had new-onset respiratory symptoms, unexplained radiographic infiltrate, and laboratory-confirmed H7N9 virus infection. We recorded histories and results of haematological, biochemical, radiological, and microbiological investigations. We took throat and sputum samples, used RT-PCR to detect M, H7, and N9 genes, and cultured samples in Madin-Darby canine kidney cells. We tested for co-infections and monitored serum concentrations of six cytokines and chemokines.We collected doacal swabs from 86 birds from epidemiologically linked wet markets and inoculated embryonated chicken eggs with the samples. We identified and subtyped isolates by RT-PCR sequencing. RNA extraction, complementary DNA synthesis, and PCR sequencing were done for one human and one chicken isolate. We characterised and phylogenetically analysed the eight gene segments of the viruses in the patient's and the chicken's isolates, and constructed phylogenetic trees of H, N, PB2, and NS genes. Findings We identified four patients (mean age 56 years), all of whom had contact with poultry 3-8 days before disease onset. They presented with fever and rapidly progressive pneumonia that did not respond to antibiotics. Patients were leucopenic and lymphopenic, and had impaired liver or renal function, substantially increased serum cytokine or chemokine concentrations, and disseminated intravascular coagulation with disease progression. Two patients died. Sputum specimens were more likely to test positive for the H7N9 virus than were samples from throat swabs. The viral isolate from the patient was closely similar to that from an epidemiologically linked market chicken. All viral gene segments were of avian origin. The H7 of the isolated viruses was closest to that of the H7N3 virus from domestic ducks in Zhejiang, whereas the N9 was closest to that of the wild bird H7N9 virus in South Korea. We noted Gln226Leu and Gly186Val substitutions in human virus H7 (associated with increased affinity for cx-2,6-1inked sialic acid receptors) and the PB2 Asp701Asn mutation (associated with mammalian adaptation). Ser31Asn mutation, which is associated with adamantane resistance, was noted in viral M2. Interpretation Cross species poultry-to-person transmission of this new reassortant H7N9 virus is associated with severe pneumonia and multiorgan dysfunction in human beings. Monitoring of the viral evolution and further study of disease pathogenesis will improve disease management, epidemic control, and pandemic preparedness. Fundin9 Larry Chi-Kin Yung, National Key Program for Infectious Diseases of China. [ABSTRACT FROM AUTHOR]

Objective: To explore whether expression of dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) and reactivation of human immunodeficiency virus type 1 (HIV-1) provirus in dendritic cells (DCs) occur through similar or common signaling pathways. Methods: Phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 cells were used as the in vitro model of DCs. The activation of the DC-SIGN promoter and HIV-1 5' long-term repeat (LTR) sequence induced by interleukin 4 (IL-4) in differentiated THP-1 cells was studied using luciferase reporter plasmids. The regulatory signaling pathways were identified using specific inhibitors, and the activity of the DC-SIGN promoter and HIV-1 5'LTR was detected. Results: HIV-1 5'LTR was activated by IL-4-induced signaling pathways but much weaker than DC-SIGN promoter. IL-4-induced activation of HIV-1 5'LTR was mainly through the nuclear factor kappalight- chain-enhancer of activated B cells (NF-êB) pathway, which was also involved in activation of the DC-SIGN promoter. The extracellular signal-regulated kinase (ERK) pathway, which was the main pathway for DC-SIGN promoter activation, also played an important role in HIV-1 5'LTR activation. Conclusion: Our study suggests that the activation of the DC-SIGN promoter and HIV-1 5'LTR may share NF-êB and ERK-signaling pathways. [ABSTRACT FROM AUTHOR]

The highly pathogenic H5N1 avian influenza virus emerged from China in 1996 and has spread across Eurasia and Africa, with a continuous stream of new cases of human infection appearing since the first large-scale outbreak among migratory birds at Qinghai Lake. The role of wild birds, which are the natural reservoirs for the virus, in the epidemiology of the H5N1 virus has raised great public health concern, but their role in the spread of the virus within the natural ecosystem of free-ranging terrestrial wild mammals remains unclear. In this study, we investigated H5N1 virus infection in wild pikas in an attempt to trace the circulation of the virus. Seroepidemiological surveys confirmed a natural H5N1 virus infection of wild pikas in their native environment. The hemagglutination gene of the H5N1 virus isolated from pikas reveals two distinct evolutionary clades, a mixed/Vietnam H5N1 virus sublineage (MV-like pika virus) and a wild bird Qinghai (QH)-like H5N1 virus sublineage (QH-like pika virus). The amino acid residue (glutamic acid) at position 627 encoded by the PB2 gene of the MV-like pika virus was different from that of the QH-like pika virus; the residue of the MV-like pika virus was the same as that of the goose H5N1 virus (A/GS/Guangdong [GD]/1/96). Further, we discovered that in contrast to the MV-like pika virus, which is nonpathogenic to mice, the QH-like pika virus is highly pathogenic. To mimic the virus infection of pikas, we intranasally inoculated rabbits, a species closely related to pikas, with the H5N1 virus of pika origin. Our findings first demonstrate that wild pikas are mammalian hosts exposed to H5N1 subtype avian influenza viruses in the natural ecosystem and also imply a potential transmission of highly pathogenic avian influenza virus from wild mammals into domestic mammalian hosts and humans. [ABSTRACT FROM AUTHOR]

Loss-of-function mutations in parkin are the major cause of early-onset familial Parkinson's disease. To investigate the pathogenic mechanism by which loss of parkin function causes Parkinson's disease, we generated a mouse model bearing a germline disruption in parkin. Parkin-/- mice are viable and exhibit grossly normal brain morphology. Quantitative in vivo microdialysis revealed an increase in extracellular dopamine concentration in the striatum of parkin-/- mice. Intracellular recordings of medium-sized striatal spiny neutons showed that greater currents are required to induce synaptic responses, suggesting a reduction in synaptic excitability in the absence of parkin. Furthermore, parkin-/- mice exhibit deficits in behavioral paradigms sensitive to dysfunction of the nigrostriatal pathway. The number of dopaminergic neurons in the substantia nigra of parkin-/- mice, however, is normal up to the age of 24 months, in contrast to the substantial loss of nigral neurons characteristic of Parkinson's disease. Steady-state levels of CDCrel-1, synphilin-1, and α-synuclein, which were identified previously as substrates of the E3 ubiquitin ligase activity of parkin, are unaltered in parkin-/- brains. Together these findings provide the first evidence for a novel role of parkin in dopamine regulation and nigrostriatal function, and a non-essential role of parkin in the survival of nigral neurons in mice. [ABSTRACT FROM AUTHOR]

The C-type lectins DC-SIGN and DC-SIGNR bind and transmit HIV-1 depending on the tetramer formed by "neck" region and carbohydrate recognition domain (CRD). Recent studies indicated polymorphisms in neck region of DC-SIGNR were more frequent and associated with susceptibility to HIV-1 infection, whereas no similar trends were observed on DC-SIGN for rare variations of DC-SIGN among the researched subjects in those studies. In our present study, we found 9 genotype variations of DC-SIGN neck region among HIV infected Germans and 3 variations among HIV infected Chinese, respectively. Comparison of those variations between Chinese and Germans reveals strong ethnic discrepancies, and no significant evidence indicates those variations have resistance to susceptibility to HIV-1 infection.