bluuebunny/crossref_metadata_2025 huggingface dataset:
Breakthrough Invasive Candida glabrata in Patients on Micafungin: a Novel
FKS
Gene Conversion Correlated with Sequential Elevation of MIC
Authors: Saraya Takeshi , Tanabe Koichi , Araki Koji , Yonetani Shota , Makino Hiroshi , Watanabe Takayasu , Tsujimoto Naoki , Takata Saori , Kurai Daisuke , Ishii Haruyuki , Miyazaki Yoshitsugu , Takizawa Hajime , Goto Hajime
Published: May 2014

Candida glabrata
strains sequentially isolated from blood developed resistance to micafungin (MICs from <0.015 to 4 μg/ml). A novel mutation identified in micafungin-resistant strains at bp 262 of
FKS2
(containing a deletion of F659 [F659del]) was inserted into the homologous region in
FKS1
.
Ineffectual Targeting of HIV-1 Nef by Cytotoxic T Lymphocytes in Acute Infection Results in No Functional Impairment or Viremia Reduction
Authors: De La Cruz Justin , Vollbrecht Thomas , Frohnen Patricia , Ng Hwee L. , Daar Eric S. , Yang Otto O. , Lewis Martha J.
Published: May 2014

The human immunodeficiency virus type 1 (HIV-1) accessory protein Nef is heavily targeted by CD8
+
T lymphocytes (CTLs) during acute infection and therefore is included in many candidate vaccines. We investigated whether CTL targeting of Nef during acute infection contributes to immune control by disrupting the function of Nef. The sequence and function of Nef in parallel with CTL responses were assessed longitudinally from peak viremia until the viremia set point in a cohort of six subjects with acute infection. All but one individual had a single founder strain. Nef-specific CTL responses were detected in all subjects and declined in magnitude over time. These responses were associated with mutations, but none of the mutations were detected in important functional motifs. Nef-mediated downregulation of CD4 and major histocompatibility complex (MHC) class I molecules was better preserved in acute infection than in chronic infection. Finally, Nef-specific CTL responses were not associated with a reduction in viremia from its acute-phase peak. Our results indicate that CTLs targeting Nef epitopes outside critical functional domains have little effect on the pathogenic functions of Nef, rendering these responses ineffective in acute infection.

IMPORTANCE
These data indicate that using the whole Nef protein as a vaccine immunogen likely allows immunodominance that leads to targeting of CTL responses that are rapidly escaped with little effect on Nef-mediated pathogenic functions. Pursuing vaccination approaches that can more precisely direct responses to vulnerable areas would maximize efficacy. Until vaccine-induced targeting can be optimized, other approaches, such as the use of Nef function inhibitors or the pursuit of immunotherapies such as T cell receptor gene therapy or adoptive transfer, may be more likely to result in successful control of viremia.
Transcriptional Suppression of miR-181c by Hepatitis C Virus Enhances Homeobox A1 Expression
Authors: Mukherjee Anupam , Shrivastava Shubham , Bhanja Chowdhury Joydip , Ray Ranjit , Ray Ratna B.
Published: May 2014

Hepatitis C virus (HCV)-induced chronic liver disease is one of the leading causes of hepatocellular carcinoma (HCC). The molecular events leading to HCC following chronic HCV infection remain poorly defined. MicroRNAs (miRNAs) have been implicated in the control of many biological processes, and their deregulation is associated with different viral infections. In this study, we observed that HCV infection of hepatocytes transcriptionally downregulates miR-181c expression by modulating CCAAT/enhancer binding protein β (C/EBP-β). Reduced expression of the pri-miR-181c transcript was noted following HCV infection.
In silico
prediction suggests that homeobox A1 (HOXA1) is a direct target of miR-181c. HOXA1 is a member of the homeodomain-containing transcription factor family and possesses pivotal roles in normal growth, development, and differentiation of mammalian tissues. Our results demonstrated that HOXA1 expression is enhanced in HCV-infected hepatocytes. Exogenous expression of the miR-181c mimic inhibits HOXA1 and its downstream molecules STAT3 and STAT5, which are involved in cell growth regulation. Interestingly, overexpression of miR-181c inhibited HCV replication by direct binding with E1 and NS5A sequences. Furthermore, accumulation of HCV genotype 2a RNA with miR-181c was observed in an RNA-induced silencing complex in Huh7.5 cells. Our results provide new mechanistic insights into the role of miR-181c in HCV-hepatocyte interactions, and miR-181c may act as a target for therapeutic intervention.

IMPORTANCE
Chronic HCV infection is one of the major causes of end-stage liver disease, including hepatocellular carcinoma. An understanding of the molecular mechanisms of HCV-mediated hepatocyte growth promotion is necessary for therapeutic intervention against HCC. In this study, we have provided evidence of HCV-mediated transcriptional downregulation of miR-181c. HCV-infected liver biopsy specimens also displayed lower expression levels of miR-181c. We have further demonstrated that inhibition of miR-181c upregulates homeobox A1 (HOXA1), which is important for hepatocyte growth promotion. Exogenous expression of miR-181c inhibited HCV replication by directly binding with HCV E1 and NS5A sequences. Taken together, our results provided new mechanistic insights for an understanding of the role of miR-181c in HCV-hepatocyte interactions and revealed miR-181c as a potential target for therapeutic intervention.
Cytomegalovirus Replication in Semen Is Associated with Higher Levels of Proviral HIV DNA and CD4
+
T Cell Activation during Antiretroviral Treatment
Authors: Gianella Sara , Massanella Marta , Richman Douglas D. , Little Susan J. , Spina Celsa A. , Vargas Milenka V. , Lada Steven M. , Daar Eric S. , Dube Michael P. , Haubrich Richard H. , Morris Sheldon R. , Smith Davey M. ,   the California Collaborative Treatment Group 592 Team
Published: May 2014

Asymptomatic cytomegalovirus (CMV) replication occurs frequently in the genital tract in untreated HIV-infected men and is associated with increased immune activation and HIV disease progression. To determine the connections between CMV-associated immune activation and the size of the viral reservoir, we evaluated the interactions between (i) asymptomatic seminal CMV replication, (ii) levels of T cell activation and proliferation in blood, and (iii) the size and transcriptional activity of the HIV DNA reservoir in blood from 53 HIV-infected men on long-term antiretroviral therapy (ART) with suppressed HIV RNA in blood plasma. We found that asymptomatic CMV shedding in semen was associated with significantly higher levels of proliferating and activated CD4
+
T cells in blood (
P
< 0.01). Subjects with detectable CMV in semen had approximately five times higher average levels of HIV DNA in blood CD4
+
T cells than subjects with no CMV. There was also a trend for CMV shedders to have increased cellular (multiply spliced) HIV RNA transcription (
P
= 0.068) compared to participants without CMV, but it is unclear if this transcription pattern is associated with residual HIV replication. In multivariate analysis, the presence of seminal plasma CMV (
P
= 0.04), detectable 2-long terminal repeat (2-LTR), and lower nadir CD4
+
(
P
< 0.01) were independent predictors of higher levels of proviral HIV DNA in blood. Interventions aimed at reducing seminal CMV and associated immune activation may be important for HIV curative strategies. Future studies of anti-CMV therapeutics will help to establish causality and determine the mechanisms underlying these described associations.

IMPORTANCE
Almost all individuals infected with HIV are also infected with cytomegalovirus (CMV), and the replication dynamics of the two viruses likely influence each other. This study investigated interactions between asymptomatic CMV replication within the male genital tract, levels of inflammation in blood, and the size of the HIV DNA reservoir in 53 HIV-infected men on long-term antiretroviral therapy (ART) with suppressed HIV RNA in blood plasma. In support of our primary hypothesis, shedding of CMV DNA in semen was associated with increased activation and proliferation of T cells in blood and also significantly higher levels of HIV DNA in blood cells. These results suggest that CMV reactivation might play a role in the maintenance of the HIV DNA reservoir during suppressive ART and that it could be a target of pharmacologic intervention in future studies.
Careers in Virology: Public Health Opportunities for Early-Career Basic Scientists
Authors: Kilianski Andy
Published: May 2014

Undergraduate, graduate, and postdoctoral scientists trained as virologists can play critical roles in public health, such as in health science policy, epidemiology, and national defense. Despite a need for basic science backgrounds within these fields, finding entry-level careers can be challenging. Volunteer opportunities are a great way for scientists to experience public health careers while still in school, and this article describes volunteering with the Medical Reserve Corps and outlines unique postgraduate opportunities for early-career virologists.
Exceptionally Potent Neutralization of Middle East Respiratory Syndrome Coronavirus by Human Monoclonal Antibodies
Authors: Ying Tianlei , Du Lanying , Ju Tina W. , Prabakaran Ponraj , Lau Candy C. Y. , Lu Lu , Liu Qi , Wang Lili , Feng Yang , Wang Yanping , Zheng Bo-Jian , Yuen Kwok-Yung , Jiang Shibo , Dimitrov Dimiter S.
Published: May 2014

The recently discovered Middle East respiratory syndrome coronavirus (MERS-CoV) continues to infect humans, with high mortality. Specific, highly effective therapeutics and vaccines against the MERS-CoV are urgently needed to save human lives and address the pandemic concerns. We identified three human monoclonal antibodies (MAbs), m336, m337, and m338, targeting the receptor (CD26/DPP4) binding domain (RBD) of the MERS-CoV spike glycoprotein from a very large naïve-antibody library (containing ∼10
11
antibodies). They bound with high affinity: equilibrium dissociation constants for the three MAbs were equal to 4.2, 9.3, and 15 nM, respectively, as measured by Biacore for Fabs binding to RBD. The avidity for IgG1 m336, m337, and m338 was even higher: 99, 820, and 560 pM, respectively. The antibodies bound to overlapping epitopes that overlap the receptor binding site on the RBD as suggested by competition experiments and further supported by site-directed mutagenesis of the RBD and a docking model of the m336-RBD complex. The highest-affinity MAb, m336, neutralized both pseudotyped and live MERS-CoV with exceptional potency, 50% neutralization at 0.005 and 0.07 μg/ml, respectively, likely by competing with DPP4 for binding to the S glycoprotein. The exceptionally high neutralization activity of these antibodies and especially m336 suggests that they have great potential for prophylaxis and therapy of MERS-CoV infection in humans and as a tool for development of vaccine immunogens. The rapid identification (within several weeks) of potent MAbs suggests a possibility to use the new large antibody library and related methodology for a quick response to the public threat resulting from emerging coronaviruses.

IMPORTANCE
A novel human coronavirus, the Middle East respiratory syndrome coronavirus (MERS-CoV), was found to infect humans with a high mortality rate in 2012, just 1 decade after the appearance of the first highly pathogenic coronavirus, severe acute respiratory syndrome coronavirus (SARS-CoV). There are no effective therapeutics available. It is highly desirable to find an approach for rapidly developing potent therapeutics against MERS-CoV, which not only can be implemented for MERS treatment but also can help to develop a platform strategy to combat future emerging coronaviruses. We report here the identification of human monoclonal antibodies (MAbs) from a large nonimmune antibody library that target MERS-CoV. One of the antibodies, m336, neutralized the virus with exceptional potency. It therefore may have great potential as a candidate therapeutic and as a reagent to facilitate the development of vaccines against MERS-CoV.
Roles of Humidity and Temperature in Shaping Influenza Seasonality
Authors: Lowen Anice C. , Steel John
Published: May 2014

Experimental studies in guinea pigs demonstrated that influenza virus transmission is strongly modulated by temperature and humidity. A number of epidemiological studies have followed up on these findings and revealed robust associations between influenza incidence in temperate regions and local conditions of humidity and temperature, offering a long-awaited explanation for the wintertime seasonality of influenza in these locales. Despite recent progress, important questions remain as to the mechanism(s) by which humidity and/or temperature affects transmission.
‘It’s on your conscience all the time’: a systematic review of qualitative studies examining views on obesity among young people aged 12–18 years in the UK
Authors: Rees Rebecca W , Caird Jenny , Dickson Kelly , Vigurs Carol , Thomas James
Published: May 2014

Objective

To explore the perspectives of young people in the UK on obesity, body size, shape and weight.

Design

Systematic review of qualitative studies using thematic synthesis.

Data sources

Sensitive searches of 18 electronic databases from 1997 to February 2010 supplemented by grey literature searches.

Study selection

Studies produced since 1997 using qualitative methods to collect perspectives of people aged 12–18 years in the UK, reporting methods for data collection or analysis. Studies of people with eating disorders and those rated low in reliability and usefulness were excluded.

Results

Searches identified 30 studies involving over 1400 young people from a range of contexts. Young people of all sizes placed considerable emphasis on personal responsibility, and on the social, rather than health implications of being overweight. Young people with experience of obesity described severe, unrelenting, size-related abuse and isolation. Regardless of their own size, young people were judgemental of individuals who were overweight, but those with experience of obesity described an environment that contained multiple barriers to weight loss. Only one study asked young people directly what might support them to have a healthy body size. Study findings were configured under three main themes, labelled with quotes from included studies: general perceptions of size and society's responses (‘It's on your conscience all the time’); the experiences of young people who were overweight (‘If I had the choice I wouldn't be this size’) and these larger young people's experiences of trying to loose weight and suggestions for action (‘Make sure, even when it's hard, you've got people there’).

Conclusions

The perspectives of young people in the UK, when synthesised across the spectrum of body sizes, paint a picture of a stigmatising and abusive social world. Research and policy need to engage young people actively so as to address the social implications of obesity.
Quality of life, support and smoking in advanced lung cancer patients: a qualitative study
Authors: Rowland C , Danson S J , Rowe R , Merrick H , Woll P J , Hatton M Q , Wadsley J , Ellis S , Crabtree C , Horsman J M , Eiser C
Published: May 2014

Background

Lung cancer is the most common cancer and smoking is the principal cause. Due to poor survival rates, symptom palliation and promotion of health-related quality of life (HRQoL) are primary outcomes for lung cancer patients. Given the established relationship between smoking and lung cancer, patients who have smoked may feel stigmatised or guilty after diagnosis, and more pessimistic about their illness and likely outcomes. This may have adverse implications for HRQoL.

Objectives

We explored HRQoL and support experiences among newly diagnosed patients with advanced lung cancer.

Design

Semistructured interviews were conducted with nine patients and analysed using interpretative phenomenological analysis.

Results

Patients described the physical, emotional and social impact of disease on HRQoL. Fear of compromising their immune system and adjusting to new relationship roles had a wide-ranging effect on patients’ HRQoL. Patients acknowledged links between lung cancer and smoking but some continued to smoke. They were sensitive to the opinions of medical staff about smoking especially those who continued to smoke or recently quit.

Conclusions

We conclude that staff should give clearer advice about the adverse implications of continued smoking. We discuss the potential value of diagnosis as a teachable moment for promoting smoking cessation among patients and family members.
Radiological and clinical features of vein of Galen malformations
Authors: Chow Maggie L , Cooke Daniel L , Fullerton Heather J , Amans Matthew R , Narvid Jared , Dowd Christopher F , Higashida Randall T , Halbach Van V , Hetts Steven W
Published: May 2014

Background

Vein of Galen malformations (VOGMs) are rare and complex congenital arteriovenous fistulas. The clinical and radiological features of VOGMs and their relation to clinical outcomes are not fully characterized.

Objective

To examine the clinical and radiological features of VOGMs and the predictors of outcome in patients.

Methods

We retrospectively reviewed the available imaging and medical records of all patients with VOGMs treated at the University of California, San Francisco between 1986 and 2013. Radiological and clinical features were identified. We applied the modified Rankin Scale to determine functional outcome by chart review. Predictors of outcome were assessed by χ2analyses.

Results

Forty-one cases were confirmed as VOGM. Most patients (78%) had been diagnosed with VOGM in the first year of life. Age at treatment was bimodally distributed, with predominantly urgent embolization at <10 days of age and elective embolization after 1 year of age. Patients commonly presented with hydrocephalus (65.9%) and congestive heart failure (61.0%). Mixed-type (31.7%) VOGM was more common in our cohort than purely mural (29.3%) or choroidal (26.8%) types. The most common feeding arteries were the choroidal and posterior cerebral arteries. Transarterial embolization with coils was the most common technique used to treat VOGMs at our institution. Functional outcome was normal or only mildly disabled in 50% of the cases at last follow-up (median=3 years, range=0–23 years). Younger age at first diagnosis, congestive heart failure, and seizures were predictive of adverse clinical outcome. The survival rate in our sample was 78.0% and complete thrombosis of the VOGM was achieved in 62.5% of patients.

Conclusions

VOGMs continue to be challenging to treat and manage. Nonetheless, endovascular approaches to treatment are continuing to be refined and improved, with increasing success. The neurodevelopmental outcomes of affected children whose VOGMs are treated may be good in many cases.
Continuous infusion of remifentanil combined with target‐controlled infusion of propofol for tracheal intubation in dogs
Authors: Pei Z. , Mao Y. , Wang S. , Tang X.
Published: May 2014

Ninety dogs presenting for elective surgery were randomly assigned into three groups of 30. Intubation conditions, haemodynamic responses and other events were evaluated following target controlled infusion (TCI) with propofol at 3.0 μg/ml, combined with variable infusion rates of remifentanil (R1 0.1 μg/kg/minute, R2 0.2 μg/kg/minute, R3 0.3 μg/kg/minute). Tracheal intubation was recorded as excellent, good or poor according to jaw relaxation, tongue withdrawal, ease of laryngoscopy, swallowing, coughing and limb movement. Excellent overall intubation conditions were present in 5/30 (17 per cent), 12/30 (40 per cent) and 21/30 (70 per cent) of dogs in groups R1–3, respectively. In all three groups, the mean arterial pressure (MAP) and mean heart rate (MHR) decreased following induction of anaesthesia. Following intubation, despite an increase in MAP and MHR values, they remained significantly lower than baseline values. Muscle twitching and involuntary movement was observed after propofol induction in 10 dogs. The results suggest that a plasma concentration of 3 μg/ml propofol along with an infusion rate of remifentanil at 0.3 μg/kg/minute may provide satisfactory conditions for intubation, while avoiding major adverse haemodynamic effects.
Risk factors associated with high bulk milk antibody levels to common pathogens in UK dairies
Authors: Williams D. , Winden S. V.
Published: May 2014

Infectious diseases pose a severe economic burden on the UK dairy industry. This study used bulk milk antibody levels in 1088 UK dairy herds to estimate the current UK prevalence of bovine viral diarrhoea virus (BVDV), bovine herpes virus 1 (BHV‐1) and Leptospira hardjo. Questionnaires collected under the DairyCheck scheme (MSD Animal Health) were used concurrently to gather information on farm demographics and management practices. The prevalence of active BVDV infection was 58.6 per cent, of historic BVDV exposure was 88.6 per cent, of BHV‐1 infection was 69.2 per cent and of L hardjo was 71.9 per cent. An increasing herd size and the purchasing of replacement cattle were risk factors for the presence of all three agents. Year‐round calving was associated with a 1.9 times increased risk for having BVDV (P<0.005). The presence of a bull was associated with a 1.5 times increased risk for having BHV‐1 (P<0.005). When compared with previous results, this study indicates a slight fall in the prevalence of BVDV within the UK dairy herd; however, BHV‐1 and L hardjo levels appear to have remained constant. This study shows that herds purchasing cattle are at greater risk of infectious agents being present and therefore, if possible, a closed herd system should be implemented.
The relationship between lower-body stiffness and dynamic performance
Authors: Pruyn Elizabeth C. , Watsford Mark , Murphy Aron
Published: May 2014

Greater levels of lower-body stiffness have been associated with improved outcomes for a number of physical performance variables involving rapid stretch-shorten cycles. The aim of this study was to investigate the relationship between several measures of lower-body stiffness and physical performance variables typically evident during team sports in female athletes. Eighteen female athletes were assessed for quasi-static stiffness (myometry) for several isolated muscles in lying and standing positions. The muscles included the medial gastrocnemius (MedGast), lateral gastrocnemius, soleus, and Achilles tendon. Dynamic stiffness during unilateral hopping was also assessed. Participants were separated into relatively stiff and compliant groups for each variable. A number of significant differences in performance were evident between stiff and compliant subjects. When considering the quasi-static stiffness of the MedGast in lying and standing positions, relatively stiff participants recorded significantly superior results during agility, bounding, sprinting, and jumping activities. Stiffness as assessed by hopping did not discriminate between performance ability in any test. Relationships highlighted by MedGast results were supported by further significant differences in eccentric utilisation ratio and drop jump results between stiff and compliant groups for the lateral gastrocnemius and soleus in lying and standing positions. Higher levels of lower-body stiffness appear to be advantageous for females when performing rapid and (or) repeated stretch-shorten cycle movements, including sprinting, bounding, and jumping. Further, the stiffness of the MedGast is of particular importance during the performance of these activities. It is important for practitioners working with athletes in sports that rely upon these activities for success to consider stiffness assessment and modification.
Microconchid tubeworms (Class Tentaculita) from the Joggins Formation (Pennsylvanian), Nova Scotia, Canada
Authors: Zatoń Michał , Grey Melissa , Vinn Olev
Published: May 2014

Microconchids have been described from the classic Pennsylvanian locality at Joggins, Nova Scotia. These encrusting tentaculitoid tubeworms have previously been mentioned and described from Joggins under the polychaete genus Spirorbis. Detailed morphological and microstructural investigation revealed that they belong to the species Microconchus carbonarius Murchison, confirming the previous tentative assignment (as Spirorbis carbonarius) made by Sir J. William Dawson in the nineteenth century. The occurrence of the same species in Upper Carboniferous deposits of England provides evidence supporting a connection between England and Nova Scotia in the Late Carboniferous (Pennsylvanian). Migration of the species could have been possible via brackish seas connecting both areas during maximum sea level during the Pennsylvanian. The species inhabited retrograding poorly drained coastal plain and open-water brackish environments, encrusting bivalve shells and plant remains in both sandstone and limestone deposits. Their high density (up to 19 individuals/cm2) may have resulted from their aggregative behaviour, high fecundity, and a lack of any competition with other skeleton-bearing encrusters. The large number (34%) of regenerated tubes indicates that microconchids were often preyed upon by associated animals, most probably fishes, which could graze on their dense encrusting aggregations.
Regional groundwater flow modelling of the confined aquifers below the Boom Clay in NE Belgium
Authors: Vandersteen K. , Gedeon M. , Marivoet J. , Wouters L.
Published: May 2014

For more than 35 years, SCK•CEN has been investigating the possibility of high-level radioactive waste disposal in the Boom Clay in northeastern Belgium. This research, defined in the long-term management programme for high and medium long-lived waste of ONDRAF/NIRAS, includes the regional hydrogeological modelling of the aquifer systems surrounding the Boom Clay. In this paper, the most recent update of the Deep Aquifer Pumping model (DAP) is described, which is capable of quantifying the regional groundwater flow in the complex confined aquifers lying below the Boom Clay in NE Belgium. The DAP model was successfully calibrated using an automated inverse optimization algorithm and is able to reproduce satisfactorily the general trends in the observed groundwater heads. This model can be used as a tool for planning future characterization efforts and reducing the predictive model uncertainty.
GSSPs, global stratigraphy and correlation
Authors: Smith Alan G. , Barry Tiffany , Bown Paul , Cope John , Gale Andy , Gibbard Philip , Gregory John , Hounslow Mark , Kemp David , Knox Robert , Marshall John , Oates Michael , Rawson Peter , Powell John , Waters Colin
Published: May 2014

Procedures used to define an international chronostratigraphic stage boundary and to locate and ratify a Global Boundary Stratotype Section and Point (GSSP) are outlined. A majority of current GSSPs use biostratigraphic data as primary markers with no reference to any physico-chemical markers, despite the International Subcommission on Stratigraphic Classification (ISSC) suggestion that such markers should be included if possible. It is argued that such definitions will not produce the high-precision Phanerozoic time scale necessary to understand such phenomena as pre-Pleistocene ice ages and global climate change. It is strongly recommended that all GSSPs should have physico-chemical markers as an integral part of their guiding criteria, and where such markers cannot be found, the GSSP should be relocated.

The methods and approach embodied in oceanic stratigraphy – coring, logging, analysing and archiving of drill sites by numerous experts using a wide range of methods – could usefully serve as a scientific model for the analysis and archiving of GSSPs, all of which are on the present-day continents. The incorporation of many more stratigraphic sections into GSSP studies, the application of physico-chemical methods, and the replacement of old U–Pb dates by newer CA-TIMS U–Pb dates, together with the use of constrained optimization (CONOP) programs that produce a calendar of events from many sections, should lead to much more precise timescales for pre-Cenozoic time than are currently available.
Mesenchymal stem cells induce epithelial proliferation within the inflamed stomach
Authors: Donnelly Jessica M. , Engevik Amy , Feng Rui , Xiao Chang , Boivin Gregory P. , Li Jing , Houghton JeanMarie , Zavros Yana
Published: May 2014

Bone marrow-derived mesenchymal stem cells (MSCs) sustain cancer cells by creating a microenvironment favorable for tumor growth. In particular, MSCs have been implicated in gastric cancer development. There is extensive evidence suggesting that Hedgehog signaling regulates tumor growth. However, very little is known regarding the precise roles of Hedgehog signaling and MSCs in tumor development within the stomach. The current study tests that hypothesis that Sonic Hedgehog (Shh), secreted from MSCs, provides a proliferative stimulus for the gastric epithelium in the presence of inflammation. Red fluorescent protein-expressing MSCs transformed in vitro (stMSCs) were transduced with lentiviral constructs containing a vector control (stMSCvect) or short hairpin RNA (shRNA) targeting the Shh gene (stMSCShhKO). Gastric submucosal transplantation of wild-type MSCs (wtMSCs), wild-type MSCs overexpressing Shh (wtMSCShh), stMSCvect, or stMSCShhKO cells in C57BL/6 control (BL/6) or gastrin-deficient (GKO) mice was performed and mice analyzed 30 and 60 days posttransplantation. Compared with BL/6 mice transplanted with wtMSCShh and stMSCvect cells, inflamed GKO mice developed aggressive gastric tumors. Tumor development was not observed in mouse stomachs transplanted with wtMSC or stMSCShhKO cells. Compared with stMSCShhKO-transplanted mice, within the inflamed GKO mouse stomach, Shh-expressing stMSCvect- and wtMSCShh-induced proliferation of CD44-positive cells. CD44-positive cells clustered in gland-like structures within the tumor stroma and were positive for Patched (Ptch) expression. We conclude that Shh, secreted from MSCs, provides a proliferative stimulus for the gastric epithelium that is associated with tumor development, a response that is sustained by chronic inflammation.
Oxidative stress and altered lipid homeostasis in the programming of offspring fatty liver by maternal obesity
Authors: Alfaradhi Maria Z. , Fernandez-Twinn Denise S. , Martin-Gronert Malgorzata S. , Musial Barbara , Fowden Abigail , Ozanne Susan E.
Published: May 2014

Changes in the maternal nutritional environment during fetal development can influence offspring's metabolic risk in later life. Animal models have demonstrated that offspring of diet-induced obese dams develop metabolic complications, including nonalcoholic fatty liver disease. In this study we investigated the mechanisms in young offspring that lead to the development of nonalcoholic fatty liver disease (NAFLD). Female offspring of C57BL/6J dams fed either a control or obesogenic diet were studied at 8 wk of age. We investigated the roles of oxidative stress and lipid metabolism in contributing to fatty liver in offspring. There were no differences in body weight or adiposity at 8 wk of age; however, offspring of obese dams were hyperinsulinemic. Oxidative damage markers were significantly increased in their livers, with reduced levels of the antioxidant enzyme glutathione peroxidase-1. Mitochondrial complex I and II activities were elevated, while levels of mitochondrial cytochrome c were significantly reduced and glutamate dehydrogenase was significantly increased, suggesting mitochondrial dysfunction. Offspring of obese dams also had significantly greater hepatic lipid content, associated with increased levels of PPARγ and reduced triglyceride lipase. Liver glycogen and protein content were concomitantly reduced in offspring of obese dams. In conclusion, offspring of diet-induced obese dams have disrupted liver metabolism and develop NAFLD prior to any differences in body weight or body composition. Oxidative stress may play a mechanistic role in the progression of fatty liver in these offspring.
Syncytial communication in descending vasa recta includes myoendothelial coupling
Authors: Zhang Zhong , Payne Kristie , Pallone Thomas L.
Published: May 2014

Using dual cell patch-clamp recording, we examined pericyte, endothelial, and myoendothelial cell-to-cell communication in descending vasa recta. Graded current injections into pericytes or endothelia yielded input resistances of 220 ± 21 and 128 ± 20 MΩ, respectively ( P < 0.05). Injection of positive or negative current into an endothelial cell depolarized and hyperpolarized adjacent endothelial cells, respectively. Similarly, current injection into a pericyte depolarized and hyperpolarized adjacent pericytes. During myoendothelial studies, current injection into a pericyte or an endothelial cell yielded small, variable, but significant change of membrane potential in heterologous cells. Membrane potentials of paired pericytes or paired endothelia were highly correlated and identical. Paired measurements of resting potentials in heterologous cells were also correlated, but with slight hyperpolarization of the endothelium relative to the pericyte, −55.2 ± 1.8 vs. −52.9 ± 2.2 mV ( P < 0.05). During dual recordings, angiotensin II or bradykinin stimulated temporally identical variations of pericyte and endothelial membrane potential. Similarly, voltage clamp depolarization of pericytes or endothelial cells induced parallel changes of membrane potential in the heterologous cell type. We conclude that the descending vasa recta endothelial syncytium is of lower resistance than the pericyte syncytium and that high-resistance myoendothelial coupling also exists. The myoendothelial communication between pericytes and endothelium maintains near identity of membrane potentials at rest and during agonist stimulation. Finally, endothelia membrane potential lies slightly below pericyte membrane potential, suggesting a tonic role for the former to hyperpolarize the latter and provide a brake on vasoconstriction.
Does the antihyperalgesic disruptor of endothelial cells, octoxynol-9, alter nociceptor function?
Authors: Chen Xiaojie , Green Paul G. , Levine Jon D.
Published: May 2014

The vasoactive mediator, endothelin-1, elicits a novel form of hyperalgesia, stimulation-dependent hyperalgesia. Acting on its cognate receptor on the vascular endothelial cell, endothelin-1 produces a state in which mechanical stimulation now elicits release of pronociceptive mediators from endothelium that, in turn, acts at receptors on sensory neurons. The only evidence that octoxynol-9, a surface-active agent that attenuates both endothelial cell function and stimulus-dependent hyperalgesia, does not affect nociceptors is indirect (i.e., octoxynol-9 treatment did not affect behavioral nociceptive threshold or hyperalgesia induced by agents that act directly on nociceptors). To help address the question of whether the attenuation of stimulation-dependent hyperalgesia by octoxynol-9 treatment is due to alteration of nociceptor function, we used in vivo single-fiber electrophysiological recordings. Consistent with our previous behavioral observations, we observed no significant effect of octoxynol-9 on mechanical threshold in nociceptors, their response to sustained suprathreshold mechanical stimulation, conduction velocity, and change in mechanical threshold in response to the direct-acting hyperalgesic agent, PGE2. Although octoxynol-9 did not produce a biologically meaningful change in parameters of nociceptor function, we cannot exclude the possibility of a type II error. However, our data provide preliminary evidence of no effect of octoxynol-9 on nociceptors and are consistent with the suggestion that the primary action of octoxynol-9 in our studies is due to its action on the endothelium.
Eye-centered visual receptive fields in the ventral intraparietal area
Authors: Chen Xiaodong , DeAngelis Gregory C. , Angelaki Dora E.
Published: May 2014

The ventral intraparietal area (VIP) processes multisensory visual, vestibular, tactile, and auditory signals in diverse reference frames. We recently reported that visual heading signals in VIP are represented in an approximately eye-centered reference frame when measured using large-field optic flow stimuli. No VIP neuron was found to have head-centered visual heading tuning, and only a small proportion of cells had reference frames that were intermediate between eye- and head-centered. In contrast, previous studies using moving bar stimuli have reported that visual receptive fields (RFs) in VIP are head-centered for a substantial proportion of neurons. To examine whether these differences in previous findings might be due to the neuronal property examined (heading tuning vs. RF measurements) or the type of visual stimulus used (full-field optic flow vs. a single moving bar), we have quantitatively mapped visual RFs of VIP neurons using a large-field, multipatch, random-dot motion stimulus. By varying eye position relative to the head, we tested whether visual RFs in VIP are represented in head- or eye-centered reference frames. We found that the vast majority of VIP neurons have eye-centered RFs with only a single neuron classified as head-centered and a small minority classified as intermediate between eye- and head-centered. Our findings suggest that the spatial reference frames of visual responses in VIP may depend on the visual stimulation conditions used to measure RFs and might also be influenced by how attention is allocated during stimulus presentation.
Gravity-dependent estimates of object mass underlie the generation of motor commands for horizontal limb movements
Authors: Crevecoeur F. , McIntyre J. , Thonnard J.-L. , Lefèvre P.
Published: May 2014

Moving requires handling gravitational and inertial constraints pulling on our body and on the objects that we manipulate. Although previous work emphasized that the brain uses internal models of each type of mechanical load, little is known about their interaction during motor planning and execution. In this report, we examine visually guided reaching movements in the horizontal plane performed by naive participants exposed to changes in gravity during parabolic flight. This approach allowed us to isolate the effect of gravity because the environmental dynamics along the horizontal axis remained unchanged. We show that gravity has a direct effect on movement kinematics, with faster movements observed after transitions from normal gravity to hypergravity (1.8g), followed by significant movement slowing after the transition from hypergravity to zero gravity. We recorded finger forces applied on an object held in precision grip and found that the coupling between grip force and inertial loads displayed a similar effect, with an increase in grip force modulation gain under hypergravity followed by a reduction of modulation gain after entering the zero-gravity environment. We present a computational model to illustrate that these effects are compatible with the hypothesis that participants partially attribute changes in weight to changes in mass and scale incorrectly their motor commands with changes in gravity. These results highlight a rather direct internal mapping between the force generated during stationary holding against gravity and the estimation of inertial loads that limb and hand motor commands must overcome.
Kv7 channels regulate pairwise spiking covariability in health and disease
Authors: Ocker Gabriel Koch , Doiron Brent
Published: May 2014

Low-threshold M currents are mediated by the Kv7 family of potassium channels. Kv7 channels are important regulators of spiking activity, having a direct influence on the firing rate, spike time variability, and filter properties of neurons. How Kv7 channels affect the joint spiking activity of populations of neurons is an important and open area of study. Using a combination of computational simulations and analytic calculations, we show that the activation of Kv7 conductances reduces the covariability between spike trains of pairs of neurons driven by common inputs. This reduction is beyond that explained by the lowering of firing rates and involves an active cancellation of common fluctuations in the membrane potentials of the cell pair. Our theory shows that the excess covariance reduction is due to a Kv7-induced shift from low-pass to band-pass filtering of the single neuron spike train response. Dysfunction of Kv7 conductances is related to a number of neurological diseases characterized by both elevated firing rates and increased network-wide correlations. We show how changes in the activation or strength of Kv7 conductances give rise to excess correlations that cannot be compensated for by synaptic scaling or homeostatic modulation of passive membrane properties. In contrast, modulation of Kv7 activation parameters consistent with pharmacological treatments for certain hyperactivity disorders can restore normal firing rates and spiking correlations. Our results provide key insights into how regulation of a ubiquitous potassium channel class can control the coordination of population spiking activity.
Learning the spatial features of a locomotor task is slowed after stroke
Authors: Tyrell Christine M. , Helm Erin , Reisman Darcy S.
Published: May 2014

The capacity for humans to learn a new walking pattern has been explored with a split-belt treadmill during single sessions of adaptation, but the split-belt treadmill can also be used to study longer-term motor learning. Although the literature provides some information about motor learning after stroke, existing studies have primarily involved the upper extremity and the results are mixed. The purpose of this study was to characterize learning of a novel locomotor task in stroke survivors. We hypothesized that the presence of neurological dysfunction from stroke would result in slower learning of a locomotor task and decreased retention of what was learned and that these deficits would be related to level of sensorimotor impairment. Sixteen participants with stroke and sixteen neurologically intact participants walked on a split-belt treadmill for 15 min on 5 consecutive days and during a retention test. Step length and limb phase were measured to capture learning of the spatial and temporal aspects of walking. Learning the spatial pattern of split-belt treadmill walking was slowed after stroke compared with neurologically intact subjects, whereas there were no differences between these two groups in learning the temporal pattern. During the retention test, poststroke participants demonstrated equal retention of the split-belt treadmill walking pattern compared with those who were neurologically intact. The results suggest that although stroke survivors are slower to learn a new spatial pattern of gait, if given sufficient time they are able to do so to the same extent as those who are neurologically intact.
Effect of amplitude correlations on coherence in the local field potential
Authors: Srinath Ramanujan , Ray Supratim
Published: May 2014

Neural activity across the brain shows both spatial and temporal correlations at multiple scales, and understanding these correlations is a key step toward understanding cortical processing. Correlation in the local field potential (LFP) recorded from two brain areas is often characterized by computing the coherence, which is generally taken to reflect the degree of phase consistency across trials between two sites. Coherence, however, depends on two factors—phase consistency as well as amplitude covariation across trials—but the spatial structure of amplitude correlations across sites and its contribution to coherence are not well characterized. We recorded LFP from an array of microelectrodes chronically implanted in the primary visual cortex of monkeys and studied correlations in amplitude across electrodes as a function of interelectrode distance. We found that amplitude correlations showed a similar trend as coherence as a function of frequency and interelectrode distance. Importantly, even when phases were completely randomized between two electrodes, amplitude correlations introduced significant coherence. To quantify the contributions of phase consistency and amplitude correlations to coherence, we simulated pairs of sinusoids with varying phase consistency and amplitude correlations. These simulations confirmed that amplitude correlations can significantly bias coherence measurements, resulting in either over- or underestimation of true phase coherence. Our results highlight the importance of accounting for the correlations in amplitude while using coherence to study phase relationships across sites and frequencies.
Mesenchymal Stem Cells from Human Fat Engineered to Secrete BMP4 Are Nononcogenic, Suppress Brain Cancer, and Prolong Survival
Authors: Li Qian , Wijesekera Olindi , Salas Sussan J. , Wang Joanna Y. , Zhu Mingxin , Aprhys Colette , Chaichana Kaisorn L. , Chesler David A. , Zhang Hao , Smith Christopher L. , Guerrero-Cazares Hugo , Levchenko Andre , Quinones-Hinojosa Alfredo
Published: May 2014

Purpose: Glioblastoma is the most common adult primary malignant intracranial cancer. It is associated with poor outcomes because of its invasiveness and resistance to multimodal therapies. Human adipose-derived mesenchymal stem cells (hAMSC) are a potential treatment because of their tumor tropism, ease of isolation, and ability to be engineered. In addition, bone morphogenetic protein 4 (BMP4) has tumor-suppressive effects on glioblastoma and glioblastoma brain tumor–initiating cells (BTIC), but is difficult to deliver to brain tumors. We sought to engineer BMP4-secreting hAMSCs (hAMSCs-BMP4) and evaluate their therapeutic potential on glioblastoma.

Experimental Design: The reciprocal effects of hAMSCs on primary human BTIC proliferation, differentiation, and migration were evaluated in vitro. The safety of hAMSC use was evaluated in vivo by intracranial coinjections of hAMSCs and BTICs in nude mice. The therapeutic effects of hAMSCs and hAMSCs-BMP4 on the proliferation and migration of glioblastoma cells as well as the differentiation of BTICs, and survival of glioblastoma-bearing mice were evaluated by intracardiac injection of these cells into an in vivo intracranial glioblastoma murine model.

Results: hAMSCs-BMP4 targeted both the glioblastoma tumor bulk and migratory glioblastoma cells, as well as induced differentiation of BTICs, decreased proliferation, and reduced the migratory capacity of glioblastomas in vitro and in vivo. In addition, hAMSCs-BMP4 significantly prolonged survival in a murine model of glioblastoma. We also demonstrate that the use of hAMSCs in vivo is safe.

Conclusions: Both unmodified and engineered hAMSCs are nononcogenic and effective against glioblastoma, and hAMSCs-BMP4 are a promising cell-based treatment option for glioblastoma. Clin Cancer Res; 20(9); 2375–87. ©2014 AACR.
Molecular Pathways: Resistance to Kinase Inhibitors and Implications for Therapeutic Strategies
Authors: Lovly Christine M. , Shaw Alice T.
Published: May 2014

The development of targeted therapies has revolutionized the treatment of cancer patients. The identification of “druggable” oncogenic kinases and the creation of small-molecule inhibitors designed to specifically target these mutant kinases have become an important therapeutic paradigm across several different malignancies. Often these inhibitors induce dramatic clinical responses in molecularly defined cohorts. However, resistance to such targeted therapies is an inevitable consequence of this therapeutic approach. Resistance can be either primary (de novo) or acquired. Mechanisms leading to primary resistance may be categorized as tumor intrinsic factors or as patient/drug-specific factors. Acquired resistance may be mediated by target gene modification, activation of “bypass tracks” that serve as compensatory signaling loops, or histologic transformation. This brief review is a snapshot of the complex problem of therapeutic resistance, with a focus on resistance to kinase inhibitors in EGF receptor mutant and ALK rearranged non–small cell lung cancer, BRAF-mutant melanoma, and BCR-ABL–positive chronic myeloid leukemia. We describe specific mechanisms of primary and acquired resistance and then review emerging strategies to delay or overcome drug resistance. Clin Cancer Res; 20(9); 2249–56. ©2014 AACR.