bluuebunny/crossref_metadata_2025 huggingface dataset:
Soluble CD146 displays angiogenic properties and promotes neovascularization in experimental hind-limb ischemia
Authors: Harhouri Karim , Kebir Abdeldjalil , Guillet Benjamin , Foucault-Bertaud Alexandrine , Voytenko Serge , Piercecchi-Marti Marie-Dominique , Berenguer Caroline , Lamy Edouard , Vely Frédéric , Pisano Pascale , Ouafik L'Houcine , Sabatier Florence , Sampol José , Bardin Nathalie , Dignat-George Françoise , Blot-Chabaud Marcel
Published: February 2010

CD146, an endothelial molecule involved in permeability and monocyte transmigration, has recently been reported to promote vessel growth. As CD146 is also detectable as a soluble form (sCD146), we hypothesized that sCD146 could stimulate angiogenesis. Experiments of Matrigel plugs in vivo showed that sCD146 displayed chemotactic activity on endogenous endothelial cells, and exogenously injected late endothelial progenitor cells (EPCs). Recruited endothelial cells participated in formation of vascular-like structures. In vitro, sCD146 enhanced angiogenic properties of EPCs, with an increased cell migration, proliferation, and capacity to establish capillary-like structures. Effects were additive with those of vascular endothelial growth factor (VEGF), and sCD146 enhanced VEGFR2 expression and VEGF secretion. Consistent with a proangiogenic role, gene expression profiling of sCD146-stimulated EPCs revealed an up-regulation of endothelial nitric oxide synthase, urokinase plasminogen activator, matrix metalloproteinase 2, and VEGFR2. Silencing membrane-bound CD146 inhibited responses. The potential therapeutic interest of sCD146 was tested in a model of hind limb ischemia. Local injections of sCD146 significantly reduced auto-amputation, tissue necrosis, fibrosis, inflammation, and increased blood flow. Together, these findings establish that sCD146 displays chemotactic and angiogenic properties and promotes efficient neovascularization in vivo. Recombinant human sCD146 might thus support novel strategies for therapeutic angiogenesis in ischemic diseases.
Correlation of the autoantibody response to the ALK oncoantigen in pediatric anaplastic lymphoma kinase–positive anaplastic large cell lymphoma with tumor dissemination and relapse risk
Authors: Ait-Tahar Kamel , Damm-Welk Christine , Burkhardt Birgit , Zimmermann Martin , Klapper Wolfram , Reiter Alfred , Pulford Karen , Woessmann Wilhelm
Published: February 2010

Anaplastic lymphoma kinase (ALK)–positive anaplastic large cell lymphoma (ALCL) constitutes an ideal model disease to study tumor-specific immune responses. All the tumor cells express oncogenic ALK resulting from a chromosomal translocation involved in lymphomagenesis. Although antibodies and T-cell responses to ALK have previously been detected in ALK-positive ALCL patients, their prognostic significance is unknown. We investigated a large cohort of uniformly treated ALK-positive pediatric ALCL patients to ascertain whether the titers of preexisting ALK autoantibodies correlated with clinical and histologic characteristics, tumor dissemination, and patient outcome. ALK autoantibodies were analyzed in pretherapeutic serum samples from 95 patients enrolled into 2 therapy studies between 1996 and 2007. ALK autoantibodies were detected in 87/95 patients. The titers inversely correlated with stage and amount of circulating tumor cells. High antibody titers correlated with significantly lower cumulative incidence of relapses (CI-R): titers ≥ 1/60 750, n = 29, CI-R 11% ± 6%; titers 1/2025-< 1/60 750, n = 39, CI-R 31% ± 8%; and titers 0-≤ 1/750, n = 27, CI-R of 63% ± 10% (P < .001). Our results provide the first clinical evidence that a robust preexisting immune response to an oncoantigen resulting from an oncogenic chromosomal translocation inhibits lymphoma dissemination and decreases the risk of relapse.
A novel clinical role for angiopoietin-1 in malignant pleural mesothelioma
Authors: Tabata C. , Hirayama N. , Tabata R. , Yasumitsu A. , Yamada S. , Murakami A. , Iida S. , Tamura K. , Fukuoka K. , Kuribayashi K. , Terada T. , Nakano T.
Published: February 2010

Malignant pleural mesothelioma (MPM) is an aggressive malignant tumour associated with asbestos exposure that has only a limited response to conventional therapy; therefore, diagnosing MPM early is very important. We have previously reported that angiopoietin (Ang)-1 was correlated with bleomycin-induced pulmonary fibrosis.

Here, we investigated the association of Ang-1 with the development of MPM cells, which originate from mesenchymal cells similar to lung fibroblasts, and demonstrated that Ang-1 stimulated the growth and migration of MPM cellsin vitro. We also demonstrated that patients with MPM had significantly higher serum levels of Ang-1 in comparison to a population who had been exposed to asbestos but had not developed MPM. The patients with advanced-stage MPM showed higher levels of Ang-1 than the early-stage MPM patients and the Kaplan–Meier method revealed a significant correlation between serum Ang-1 levels and survival.

We propose the possibility that Ang-1 plays an important role in MPM tumour growth and our data suggest that the serum concentration of Ang-1 could be useful as prognostic factor.
The impact of a delay in intensive care unit admission for community-acquired pneumonia
Authors: Phua J. , Ngerng W.J. , Lim T.K.
Published: February 2010

The primary objective of the present study was to evaluate the effect on hospital mortality of a delay in intensive care unit (ICU) admission for severe community-acquired pneumonia (CAP). The secondary objectives were to assess if such delays were associated with treatment variations by the emergency department (ED) and deterioration in the general wards, and to evaluate the prognostic ability of the Infectious Disease Society of America (IDSA)/American Thoracic Society (ATS) minor criteria.

We retrospectively compared patients who were admitted straight from the ED to the ICU (direct group, n = 54) and those who were first admitted from the ED to the general wards before ICU transfer (delayed group, n = 49), over 2.5 yrs.

Even after excluding patients who required mechanical ventilation and/or vasopressors at the ED, delayed ICU admission was an independent predictor of hospital mortality (OR 9.61). The delayed group received fewer fluid boluses in the ED and rapidly deteriorated in the general wards. The presence of ≥3 IDSA/ATS minor criteria was associated with increased mortality in the delayed group.

In conclusion, prompt recognition of severe CAP using the IDSA/ATS minor criteria, followed by aggressive management at the ED and direct ICU admission, are all crucial toward improving outcomes.
Procalcitonin guidance and reduction of antibiotic use in acute respiratory tract infection
Authors: Burkhardt O. , Ewig S. , Haagen U. , Giersdorf S. , Hartmann O. , Wegscheider K. , Hummers-Pradier E. , Welte T.
Published: February 2010

Increasing worldwide development of antimicrobial resistance and the association of resistance development and antibiotic overuse make it necessary to seek strategies for safely reducing antibiotic use and selection pressure.

In a first step, in a non-interventional study, the antibiotic prescription rates, initial procalcitonin (PCT) levels and outcome of 702 patients presenting with acute respiratory infection at 45 primary care physicians were observed. The second part was a randomised controlled non-inferiority trial comparing standard care with PCT-guided antimicrobial treatment in 550 patients in the same setting. Antibiotics were recommended at a PCT threshold of 0.25 ng·mL−1. Clinical overruling was permitted. The primary end-point for non-inferiority was number of days with significant health impairment after 14 days.

Antibiotics were prescribed in 30.3% of enrolled patients in the non-interventional study. In the interventional study, 36.7% of patients in the control group received antibiotics as compared to 21.5% in the PCT-guided group (41.6% reduction). In the modified intention-to-treat analysis, the numbers of days with significant health impairment were similar (mean 9.04versus9.00 for PCT-guided and control group, respectively; difference 0.04; 95% confidence interval -0.73–0.81). This was also true after adjusting for the most important confounders. In the PCT group, advice was overruled in 36 cases. There was no significant difference in primary end-point when comparing the PCT group treated as advised, the overruled PCT group and the control group (9.008versus9.250versus9.000 days; p = 0.9605).

A simple one-point PCT measurement for guiding decisions on antibiotic treatment is non-inferior to standard treatment in terms of safety, and effectively reduced the antibiotic treatment rate by 41.6%.
Characteristics of hospitalised patients with 2009 H1N1 influenza in Chile
Authors: Riquelme R. , Riquelme M. , Rioseco M.L. , Inzunza C. , Gomez Y. , Contreras C. , Riquelme J. , Peyrani P. , Wiemken T. , Ramirez J.
Published: February 2010

As the pandemic of 2009 H1N1 influenza A virus progressed, more patients required hospitalisation. The objective of this study is to describe the characteristics and clinical course of hospitalised patients with 2009 H1N1 virus infection in Chile.

This was a prospective, observational study of 100 consecutive hospitalised patients with RT-PCR-confirmed 2009 H1N1 influenza A, admitted to Puerto Montt General Hospital (Puerto Montt, Chile). Information was obtained regarding contact history, demographics, laboratory values and clinical course.

The primary reason for hospitalisation was pneumonia, in 75% of patients. Rapid influenza A test was positive in 51% of patients. Prior exposure to 2009 H1N1 virus was documented in 21% of patients. Clinical failure, documented in 18% of cases, was characterised by respiratory failure and acute respiratory distress syndrome. Failure was more common in patients with obesity, tachypnoea, confusion and multilobar infiltrates.

When evaluating a patient hospitalised with influenza-like illness, a negative rapid test for influenza A or negative contact with a suspected case should not alter physicians' considerations regarding the likelihood of 2009 H1N1 virus infection. Patients with 2009 H1N1 virus infection with obesity, tachypnoea, confusion and multilobar infiltrates should be closely monitored since they are at high risk for clinical failure.
SplicerAV: a tool for mining microarray expression data for changes in RNA processing
Authors: Robinson Timothy J , Dinan Michaela A , Dewhirst Mark , Garcia-Blanco Mariano A , Pearson James L
Published: February 2010

Background

Over the past two decades more than fifty thousand unique clinical and biological samples have been assayed using the Affymetrix HG-U133 and HG-U95 GeneChip microarray platforms. This substantial repository has been used extensively to characterize changes in gene expression between biological samples, but has not been previously mined en masse for changes in mRNA processing. We explored the possibility of using HG-U133 microarray data to identify changes in alternative mRNA processing in several available archival datasets.

Results

Data from these and other gene expression microarrays can now be mined for changes in transcript isoform abundance using a program described here, SplicerAV. Using in vivo and in vitro breast cancer microarray datasets, SplicerAV was able to perform both gene and isoform specific expression profiling within the same microarray dataset. Our reanalysis of Affymetrix U133 plus 2.0 data generated by in vitro over-expression of HRAS, E2F3, beta-catenin (CTNNB1), SRC, and MYC identified several hundred oncogene-induced mRNA isoform changes, one of which recognized a previously unknown mechanism of EGFR family activation. Using clinical data, SplicerAV predicted 241 isoform changes between low and high grade breast tumors; with changes enriched among genes coding for guanyl-nucleotide exchange factors, metalloprotease inhibitors, and mRNA processing factors. Isoform changes in 15 genes were associated with aggressive cancer across the three breast cancer datasets.

Conclusions

Using SplicerAV, we identified several hundred previously uncharacterized isoform changes induced by in vitro oncogene over-expression and revealed a previously unknown mechanism of EGFR activation in human mammary epithelial cells. We analyzed Affymetrix GeneChip data from over 400 human breast tumors in three independent studies, making this the largest clinical dataset analyzed for en masse changes in alternative mRNA processing. The capacity to detect RNA isoform changes in archival microarray data using SplicerAV allowed us to carry out the first analysis of isoform specific mRNA changes directly associated with cancer survival.
Genetic dissection of rice grain shape using a recombinant inbred line population derived from two contrasting parents and fine mapping a pleiotropic quantitative trait locus qGL7
Authors: Bai Xufeng , Luo Lijun , Yan Wenhao , Kovi Mallikarjuna Rao , Zhan Wei , Xing Yongzhong
Published: February 2010

Background

The three-dimensional shape of grain, measured as grain length, width, and thickness (GL, GW, and GT), is one of the most important components of grain appearance in rice. Determining the genetic basis of variations in grain shape could facilitate efficient improvements in grain appearance. In this study, an F7:8 recombinant inbred line population (RIL) derived from a cross between indica and japonica cultivars (Nanyangzhan and Chuan7) contrasting in grain size was used for quantitative trait locus (QTL) mapping. A genetic linkage map was constructed with 164 simple sequence repeat (SSR) markers. The major aim of this study was to detect a QTL for grain shape and to fine map a minor QTL, qGL7.

Results

Four QTLs for GL were detected on chromosomes 3 and 7, and 10 QTLs for GW and 9 QTLs for GT were identified on chromosomes 2, 3, 5, 7, 9 and 10, respectively. A total of 28 QTLs were identified, of which several are reported for the first time; four major QTLs and six minor QTLs for grain shape were also commonly detected in both years. The minor QTL, qGL7, exhibited pleiotropic effects on GL, GW, GT, 1000-grain weight (TGW), and spikelets per panicle (SPP) and was further validated in a near isogenic F2 population (NIL-F2). Finally, qGL7 was narrowed down to an interval between InDel marker RID711 and SSR marker RM6389, covering a 258-kb region in the Nipponbare genome, and cosegregated with InDel markers RID710 and RID76.

Conclusion

Materials with very different phenotypes were used to develop mapping populations to detect QTLs because of their complex genetic background. Progeny tests proved that the minor QTL, qGL7, could display a single mendelian characteristic. Therefore, we suggested that minor QTLs for traits with high heritability could be isolated using a map-based cloning strategy in a large NIL-F2 population. In addition, combinations of different QTLs produced diverse grain shapes, which provide the ability to breed more varieties of rice to satisfy consumer preferences.
Hyper-expansion of large DNA segments in the genome of kuruma shrimp, Marsupenaeus japonicus
Authors: Koyama Takashi , Asakawa Shuichi , Katagiri Takayuki , Shimizu Atsushi , Fagutao Fernand F , Mavichak Rapeepat , Santos Mudjekeewis D , Fuji Kanako , Sakamoto Takashi , Kitakado Toshihide , Kondo Hidehiro , Shimizu Nobuyoshi , Aoki Takashi , Hirono Ikuo
Published: February 2010

Background

Higher crustaceans (class Malacostraca) represent the most species-rich and morphologically diverse group of non-insect arthropods and many of its members are commercially important. Although the crustacean DNA sequence information is growing exponentially, little is known about the genome organization of Malacostraca. Here, we constructed a bacterial artificial chromosome (BAC) library and performed BAC-end sequencing to provide genomic information for kuruma shrimp (Marsupenaeus japonicus), one of the most widely cultured species among crustaceans, and found the presence of a redundant sequence in the BAC library. We examined the BAC clone that includes the redundant sequence to further analyze its length, copy number and location in the kuruma shrimp genome.

Results

Mj024A04 BAC clone, which includes one redundant sequence, contained 27 putative genes and seemed to display a normal genomic DNA structure. Notably, of the putative genes, 3 genes encode homologous proteins to the inhibitor of apoptosis protein and 7 genes encode homologous proteins to white spot syndrome virus, a virulent pathogen known to affect crustaceans. Colony hybridization and PCR analysis of 381 BAC clones showed that almost half of the BAC clones maintain DNA segments whose sequences are homologous to the representative BAC clone Mj024A04. The Mj024A04 partial sequence was detected multiple times in the kuruma shrimp nuclear genome with a calculated copy number of at least 100. Microsatellites based BAC genotyping clearly showed that Mj024A04 homologous sequences were cloned from at least 48 different chromosomal loci. The absence of micro-syntenic relationships with the available genomic sequences of Daphnia and Drosophila suggests the uniqueness of these fragments in kuruma shrimp from current arthropod genome sequences.

Conclusions

Our results demonstrate that hyper-expansion of large DNA segments took place in the kuruma shrimp genome. Although we analyzed only a part of the duplicated DNA segments, our result suggested that it is difficult to analyze the shrimp genome following normal analytical methodology. Hence, it is necessary to avoid repetitive sequence (such as segmental duplications) when studying the other unique structures in the shrimp genome.
JAM-A is a novel surface marker for NG2-Glia in the adult mouse brain
Authors: Stelzer Sandra , Ebnet Klaus , Schwamborn Jens C
Published: February 2010

Background

Junctional adhesion molecule-A (JAM-A) is an adhesive protein expressed in various cell types. JAM-A localizes to the tight junctions between contacting endothelial and epithelial cells, where it contributes to cell-cell adhesion and to the control of paracellular permeability.

Results

So far, the expression pattern of JAM-A has not been described in detail for the different cell types of the adult brain. Here we show that a subset of proliferating cells in the adult mouse brain express JAM-A. We further clarify that these cells belong to the lineage of NG2-glia cells. Although these mitotic NG2-glia cells express JAM-A, the protein never shows a polarized subcellular distribution. Also non-mitotic NG2-glia cells express JAM-A in a non-polarized pattern on their surface.

Conclusions

Our data show that JAM-A is a novel surface marker for NG2-glia cells of the adult brain.
Calcium imaging in the ant Camponotus fellah reveals a conserved odour-similarity space in insects and mammals
Authors: Dupuy Fabienne , Josens Roxana , Giurfa Martin , Sandoz Jean-Christophe
Published: February 2010

Background

Olfactory systems create representations of the chemical world in the animal brain. Recordings of odour-evoked activity in the primary olfactory centres of vertebrates and insects have suggested similar rules for odour processing, in particular through spatial organization of chemical information in their functional units, the glomeruli. Similarity between odour representations can be extracted from across-glomerulus patterns in a wide range of species, from insects to vertebrates, but comparison of odour similarity in such diverse taxa has not been addressed. In the present study, we asked how 11 aliphatic odorants previously tested in honeybees and rats are represented in the antennal lobe of the ant Camponotus fellah, a social insect that relies on olfaction for food search and social communication.

Results

Using calcium imaging of specifically-stained second-order neurons, we show that these odours induce specific activity patterns in the ant antennal lobe. Using multidimensional analysis, we show that clustering of odours is similar in ants, bees and rats. Moreover, odour similarity is highly correlated in all three species.

Conclusion

This suggests the existence of similar coding rules in the neural olfactory spaces of species among which evolutionary divergence happened hundreds of million years ago.
Mammographic density and markers of socioeconomic status: a cross-sectional study
Authors: Aitken Zoe , Walker Kate , Stegeman Bernardine H , Wark Petra A , Moss Sue M , McCormack Valerie A , dos Santos Silva Isabel
Published: February 2010

Background

Socioeconomic status (SES) is known to be positively associated with breast cancer risk but its relationship with mammographic density, a marker of susceptibility to breast cancer, is unclear. This study aims to investigate whether mammographic density varies by SES and to identify the underlying anthropometric, lifestyle and reproductive factors leading to such variation.

Methods

In a cross-sectional study of mammographic density in 487 pre-menopausal women, SES was assessed from questionnaire data using highest achieved level of formal education, quintiles of Census-derived Townsend scores and urban/rural classification of place of residence. Mammographic density was measured on digitised films using a computer-assisted method. Linear regression models were fitted to assess the association between SES variables and mammographic density, adjusting for correlated variables.

Results

In unadjusted models, percent density was positively associated with SES, with an absolute difference in percent density of 6.3% (95% CI 1.6%, 10.5%) between highest and lowest educational categories, and of 6.6% (95% CI -0.7%, 12.9%) between highest and lowest Townsend quintiles. These associations were mainly driven by strong negative associations between these SES variables and lucent area and were attenuated upon adjustment for body mass index (BMI). There was little evidence that reproductive factors explained this association. SES was not associated with the amount of dense tissue in the breast before or after BMI adjustment. The effect of education on percent density persisted after adjustment for Townsend score. Mammographic measures did not vary according to urban/rural place of residence.

Conclusions

The observed SES gradients in percent density paralleled known SES gradients in breast cancer risk. Although consistent with the hypothesis that percent density may be a mediator of the SES differentials in breast cancer risk, the SES gradients in percent density were mainly driven by the negative association between SES and BMI. Nevertheless, as density affects the sensitivity of screen-film mammography, the higher percent density found among high SES women would imply that these women have a higher risk of developing cancer but a lower likelihood of having it detected earlier.
In-depth investigation of the molecular pathogenesis of bladder cancer in a unique 26-year old patient with extensive multifocal disease: a case report
Authors: Zuiverloon Tahlita CM , Abas Cheno S , van der Keur Kirstin A , Vermeij Marcel , Tjin Stephen S , van Tilborg Angela G , Busstra Martijn , Zwarthoff Ellen C
Published: February 2010

Background

The molecular characteristics and the clinical disease course of bladder cancer (BC) in young patients remain largely unresolved. All patients are monitored according to an intensive surveillance protocol and we aim to gain more insight into the molecular pathways of bladder tumors in young patients that could ultimately contribute to patient stratification, improve patient quality of life and reduce associated costs. We also determined whether a biomarker-based surveillance could be feasible.

Case Presentation

We report a unique case of a 26-year-old Caucasian male with recurrent non-muscle invasive bladder tumors occurring at a high frequency and analyzed multiple tumors (maximal pTaG2) and urine samples of this patient. Analysis included FGFR3 mutation detection, FGFR3 and TP53 immunohistochemistry, mircosatellite analysis of markers on chromosomes 8, 9, 10, 11 and 17 and a genome wide single nucleotide polymorphism-array (SNP). All analyzed tumors contained a mutation in FGFR3 and were associated with FGFR3 overexpression. None of the tumors showed overexpression of TP53. We found a deletion on chromosome 9 in the primary tumor and this was confirmed by the SNP-array that showed regions of loss on chromosome 9. Detection of all recurrences was possible by urinary FGFR3 mutation analysis.

Conclusions

Our findings would suggest that the BC disease course is determined by not only a patient's age, but also by the molecular characteristics of a tumor. This young patient contained typical genetic changes found in tumors of older patients and implies a clinical disease course comparable to older patients. We demonstrate that FGFR3 mutation analysis on voided urine is a simple non-invasive method and could serve as a feasible follow-up approach for this young patient presenting with an FGFR3 mutant tumor.
Medical student engagement and leadership within a new learning community
Authors: Bicket Mark , Misra Satish , Wright Scott M , Shochet Robert
Published: February 2010

Background

Many medical schools are establishing learning communities to foster cohesion among students and to strengthen relationships between students and faculty members. Emerging learning communities require nurturing and attention; this represents an opportunity wherein medical students can become involved as leaders. This study sought to understand issues related to active involvement among students who chose to become highly engaged in a newly developed learning community.

Methods

Between April and June 2008, 36 students who assumed leadership roles within the Colleges Program were queried electronically with open-ended questions about their engagement. Qualitative analysis of the written responses was independently performed by two investigators; coding was compared for agreement. Content analysis identified major themes.

Results

35 students (97%) completed the questionnaire. Motives that emerged as reasons for getting involved included: endorsing the need for the program; excitement with the start-up; wanting to give back; commitment to institutional excellence; and collaboration with talented peers and faculty. Perceived benefits were grouped under the following domains: connecting with others; mentoring; learning new skills; and recognition. The most frequently identified drawbacks were the time commitment and the opportunity costs. Ideas for drawing medical students into new endeavors included: creating defined roles; offering a breadth of opportunities; empowering students with responsibility; and making them feel valued.

Conclusions

Medical students were drawn to and took on leadership roles in a medical school curricular innovation. This example may prove helpful to others hoping to engage students as leaders in learning communities at their schools or those wishing to augment student involvement in other programs.
A role for NRAGE in NF-κB activation through the non-canonical BMP pathway
Authors: Matluk Nicholas , Rochira Jennifer A , Karaczyn Aldona , Adams Tamara , Verdi Joseph M
Published: February 2010

Background

Previous studies have linked neurotrophin receptor-interacting MAGE protein to the bone morphogenic protein signaling pathway and its effect on p38 mediated apoptosis of neural progenitor cells via the XIAP-Tak1-Tab1 complex. Its effect on NF-κB has yet to be explored.

Results

Herein we report that NRAGE, via the same XIAP-Tak1-Tab1 complex, is required for the phosphorylation of IKK -α/β and subsequent transcriptional activation of the p65 subunit of NF-κB. Ablation of endogenous NRAGE by siRNA inhibited NF-κB pathway activation, while ablation of Tak1 and Tab1 by morpholino inhibited overexpression of NRAGE from activating NF-κB. Finally, cytokine profiling of an NRAGE over-expressing stable line revealed the expression of macrophage migration inhibitory factor.

Conclusion

Modulation of NRAGE expression revealed novel roles in regulating NF-κB activity in the non-canonical bone morphogenic protein signaling pathway. The expression of macrophage migration inhibitory factor by bone morphogenic protein -4 reveals novel crosstalk between an immune cytokine and a developmental pathway.
Alteration of Primary Afferent Activity following Inferior Alveolar Nerve Transection in Rats
Authors: Nakagawa Kazuharu , Takeda Mamoru , Tsuboi Yoshiyuki , Kondo Masahiro , Kitagawa Junichi , Matsumoto Shigeji , Kobayashi Azusa , Sessle Barry J , Shinoda Masamichi , Iwata Koichi
Published: February 2010

Background:

In order to evaluate the neural mechanisms underlying the abnormal facial pain that may develop following regeneration of the injured inferior alveolar nerve (IAN), the properties of the IAN innervated in the mental region were analyzed.

Results:

Fluorogold (FG) injection into the mental region 14 days after IAN transection showed massive labeling of trigeminal ganglion (TG). The escape threshold to mechanical stimulation of the mental skin was significantly lower (i.e. mechanical allodynia) at 11–14 days after IAN transection than before surgery. The background activity, mechanically evoked responses and afterdischarges of IAN Aδ-fibers were significantly higher in IAN-transected rats than naive. The small/medium diameter TG neurons showed an increase in both tetrodotoxin (TTX)-resistant (TTX-R) and -sensitive (TTX-S) sodium currents ( INa) and decrease in total potassium current, transient current ( IA) and sustained current ( IK) in IAN-transected rats. The amplitude, overshoot amplitude and number of action potentials evoked by the depolarizing pulses after 1 μM TTX administration in TG neurons were significantly higher, whereas the threshold current to elicit spikes was smaller in IAN-transected rats than naive. Resting membrane potential was significantly smaller in IAN-transected rats than that of naive.

Conclusions:

These data suggest that the increase in both TTX-S INa and TTX-R INa and the decrease in IA and Ik in small/medium TG neurons in IAN-transected rats are involved in the activation of spike generation, resulting in hyperexcitability of Aδ-IAN fibers innervating the mental region after IAN transection.
Akt activity protects rheumatoid synovial fibroblasts from Fas-induced apoptosis by inhibition of Bid cleavage
Authors: García Samuel , Liz Myriam , Gómez-Reino Juan J , Conde Carmen
Published: February 2010

Introduction

Synovial hyperplasia is a main feature of rheumatoid arthritis pathology that leads to cartilage and bone damage in the inflamed joints. Impaired apoptosis of resident synoviocytes is pivotal in this process. Apoptosis resistance seems to involve defects in the extrinsic and intrinsic apoptotic pathways. The aim of this study was to investigate the association of PI3Kinase/Akt and the mitochondrial apoptotic pathway in the resistance of rheumatoid arthritis (RA) fibroblast like synovial cells (FLS) to Fas-mediated apoptosis.

Methods

Apoptosis was assessed by ELISA quantification of nucleosomal release, Hoechst staining and activated caspase-3/7 measure in cultured RA FLS stimulated with anti-Fas antibody. Two Phosphoinositol-3-kinase/protein Kinase B (PI3 Kinase) inhibitors, Wortmannine and LY294002, were used before anti-Fas stimulation. Proapoptotic BH3 interacting domain death agonist (Bid) was suppressed in RA FLS by small interfering RNA (siRNA) transfection. Bid was overexpressed by transfection with the pDsRed2-Bid vector. Phosphorylated Akt, caspase-9, and Bid expression were analysed by western blot.

Results

PI3 kinase inhibition sensitizes RA FLS to Fas-induced apoptosis by increasing cleavage of Bid protein. Bid suppression completely abrogated Fas-induced apoptosis and Bid overexpression highly increased apoptotic rate of RA FLS in association with cleavage of caspase-9.

Conclusions

In RA FLS, phosphorylation of Akt protects against Fas-induced apoptosis through inhibition of Bid cleavage. The connection between the extrinsic and the intrinsic apoptotic pathways are critical in this Fas- mediated apoptosis and points to PI3Kinase as potential therapeutic target for RA.
Identification of functional modules that correlate with phenotypic difference: the influence of network topology
Authors: Hung Jui-Hung , Whitfield Troy W , Yang Tun-Hsiang , Hu Zhenjun , Weng Zhiping , DeLisi Charles
Published: February 2010

One of the important challenges to post-genomic biology is relating observed phenotypic alterations to the underlying collective alterations in genes. Current inferential methods, however, invariably omit large bodies of information on the relationships between genes. We present a method that takes account of such information - expressed in terms of the topology of a correlation network - and we apply the method in the context of current procedures for gene set enrichment analysis.
Increased Hypothalamic Signal Transducer and Activator of Transcription 3 Phosphorylation after Hindbrain Leptin Injection
Authors: Ruiter Marieke , Duffy Patricia , Simasko Steven , Ritter Robert C.
Published: February 2010

Reduction of food intake and body weight by leptin is attributed largely to its action in the hypothalamus. However, the signaling splice variant of the leptin receptor, LRb, also is expressed in the hindbrain, and leptin injections into the fourth cerebral ventricle or dorsal vagal complex are associated with reductions of feeding and body weight comparable to those induced by forebrain leptin administration. Although these observations suggest direct hindbrain action of leptin on feeding and body weight, the possibility that hindbrain leptin administration also activates the Janus kinase/signal transducer and activator of transcription 3 (STAT3) signaling in the hypothalamus has not been investigated. Confirming earlier work, we found that leptin produced comparable reductions of feeding and body weight when injected into the lateral ventricle or the fourth ventricle. We also found that lateral and fourth ventricle leptin injections produced comparable increases of STAT3 phosphorylation in both the hindbrain and the hypothalamus. Moreover, injection of 50 ng of leptin directly into the nucleus of the solitary tract also increased STAT3 phosphorylation in the hypothalamic arcuate and ventromedial nuclei. Increased hypothalamic STAT3 phosphorylation was not due to elevation of blood leptin concentrations and the pattern of STAT3 phosphorylation did not overlap distribution of the retrograde tracer, fluorogold, injected via the same cannula. Our observations indicate that even small leptin doses administered to the hindbrain can trigger leptin-related signaling in the forebrain, and raise the possibility that STAT3 phosphorylation in the hypothalamus may contribute to behavioral and metabolic changes observed after hindbrain leptin injections.
Estrogen Receptor α Gene Promoter 0/B Usage in the Rat Sexually Dimorphic Nucleus of the Preoptic Area
Authors: Hamada Tomohiro , Sakuma Yasuo
Published: February 2010

The volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA) is two to four times larger in male rats than in females; however, the mechanism for the establishment of sexual dimorphism and the function of this nucleus is almost unknown. Perinatal estrogen can cause sexual dimorphism via the estrogen receptor α (ERα). Recently, transgenic rats were generated that express enhanced green fluorescent protein (EGFP) under the control of the ERα gene promoter 0/B to tag ERα-positive neurons in the brain. In the present study, we examined whether this EGFP expression could be a marker for the SDN-POA in adults. EGFP-labeled cells were distributed in the core of the SDN-POA (0/B-SDN) of male and female transgenic rats, in accordance with the Nissl staining and immunoreactivity for the SDN marker, calbindin. They were also immunoreactive for ERα. The core was bigger in volume and contained more 0/B-SDN neurons in males than in females. The EGFP-tagged cells were packed more densely in the female core than that in males. Subcutaneous injection of 100 μg 17β-estradiol to females on the day of birth, or orchidectomy of male neonates, reversed the sexually dimorphic phenotype of the volume of the 0/B-SDN, despite not affecting the cell number. We suggest that this EGFP expression in the SDN-POA could be a useful marker to clarify the sexual differentiation and function of the SDN-POA. Moreover, the ERα gene promoter 0/B plays a key role in the organization of the sexual differentiation of the SDN-POA.
A Postweaning Reduction in Circulating Ghrelin Temporarily Alters Growth Hormone (GH) Responsiveness to GH-Releasing Hormone in Male Mice But Does Not Affect Somatic Growth
Authors: Ariyasu Hiroyuki , Iwakura Hiroshi , Yamada Go , Kanamoto Naotetsu , Bando Mika , Kohno Kenji , Sato Takahiro , Kojima Masayasu , Nakao Kazuwa , Kangawa Kenji , Akamizu Takashi
Published: February 2010

Ghrelin was initially identified as an endogenous ligand for the GH secretagogue receptor. When administrated exogenously, ghrelin stimulates GH release and food intake. Previous reports in ghrelin-null mice, which do not exhibit impaired growth nor appetite, question the physiologic role of ghrelin in the regulation of the GH/IGF-I axis. In this study, we generated a transgenic mouse that expresses human diphtheria toxin (DT) receptor (DTR) cDNA in ghrelin-secretion cells [ghrelin-promoter DTR-transgenic (GPDTR-Tg) mice]. Administration of DT to this mouse ablates ghrelin-secretion cells in a controlled manner. After injection of DT into GPDTR-Tg mice, ghrelin-secreting cells were ablated, and plasma levels of ghrelin were markedly decreased [nontransgenic littermates, 70.6 ± 10.2 fmol/ml vs. GPDTR-Tg, 5.3 ± 2.3 fmol/ml]. To elucidate the physiological roles of circulating ghrelin on GH secretion and somatic growth, 3-wk-old GPDTR-Tg mice were treated with DT twice a week for 5 wk. The GH responses to GHRH in male GPDTR-Tg mice were significantly lower than those in wild-type mice at 5 wk of age. However, those were normalized at 8 wk of age. In contrast, in female mice, there was no difference in GH response to GHRH between GPDTR-Tg mice and controls at 5 or 8 wk of age. The gender-dependent differences in response to GHRH were observed in ghrelin-ablated mice. However, GPDTR-Tg mice did not display any decreases in IGF-I levels or any growth retardation. Our results strongly suggest that circulating ghrelin does not play a crucial role in somatic growth.
A Novel Effect of Growth Hormone on Macrophage Modulates Macrophage-Dependent Adipocyte Differentiation
Authors: Lu Chunxia , Kumar P. Anil , Fan Yong , Sperling Mark A. , Menon Ram K.
Published: February 2010

The GH receptor (GHR) is expressed on macrophages. However, the precise role of GH in regulation of macrophage function is unclear. We hypothesized that soluble factors including cytokines produced by macrophages in a GH-dependent manner regulate adipogenesis. We confirmed expression and functional integrity of the GHR in the J774A.1 macrophage cells. Conditioned medium (CM) from macrophages inhibited adipogenesis in a 3T3-L1 adipogenesis assay. CM from GH-treated macrophages decreased the inhibitory effect of CM from macrophages on adipogenesis. This effect on preadipocyte differentiation was active only during the first (early) phase of adipocyte differentiation. CM from stromal vascular compartment macrophages of mice with macrophage-specific deletion of the GHR exhibited more inhibitory effect on 3T3-L1 preadipocyte differentiation compared with CM from stromal vascular compartment macrophages of control mice, indicating that intact GH action in primary macrophages also increases preadipocyte differentiation. GH did not increase IGF-1 expression in macrophages. PCR array analysis identified IL-1β as a candidate cytokine whose expression was altered by GH in macrophages. Levels of IL-1β mRNA and protein were significantly decreased in GH-treated J774A.1 macrophages. Nuclear factor-κB stimulates IL-1β gene expression, and GH induced a significant decrease in the levels of phosphorylated nuclear factor-κB in macrophages. IL-1β is a known inhibitor of adipogenesis, and these results support GH-dependent down-regulation of macrophage IL-1β expression as one mechanism for the observed increase in adipogenesis with CM from GH-treated macrophages. We conclude that GH decreases secretion of IL-1β by the macrophage and thus in a paracrine manner increases adipocyte differentiation. These results provide a novel mechanism for GH’s actions in the control of adipogenesis.
Activation of Peroxisome Proliferator-Activated Receptor-δ by GW501516 Prevents Fatty Acid-Induced Nuclear Factor-κB Activation and Insulin Resistance in Skeletal Muscle Cells
Authors: Coll Teresa , Álvarez-Guardia David , Barroso Emma , Gómez-Foix Anna Maria , Palomer Xavier , Laguna Juan C. , Vázquez-Carrera Manuel
Published: February 2010

Elevated plasma free fatty acids cause insulin resistance in skeletal muscle through the activation of a chronic inflammatory process. This process involves nuclear factor (NF)-κB activation as a result of diacylglycerol (DAG) accumulation and subsequent protein kinase Cθ (PKCθ) phosphorylation. At present, it is unknown whether peroxisome proliferator-activated receptor-δ (PPARδ) activation prevents fatty acid-induced inflammation and insulin resistance in skeletal muscle cells. In C2C12 skeletal muscle cells, the PPARδ agonist GW501516 prevented phosphorylation of insulin receptor substrate-1 at Ser307 and the inhibition of insulin-stimulated Akt phosphorylation caused by exposure to the saturated fatty acid palmitate. This latter effect was reversed by the PPARδ antagonist GSK0660. Treatment with the PPARδ agonist enhanced the expression of two well known PPARδ target genes involved in fatty acid oxidation, carnitine palmitoyltransferase-1 and pyruvate dehydrogenase kinase 4 and increased the phosphorylation of AMP-activated protein kinase, preventing the reduction in fatty acid oxidation caused by palmitate exposure. In agreement with these changes, GW501516 treatment reversed the increase in DAG and PKCθ activation caused by palmitate. These effects were abolished in the presence of the carnitine palmitoyltransferase-1 inhibitor etomoxir, thereby indicating that increased fatty acid oxidation was involved in the changes observed. Consistent with these findings, PPARδ activation by GW501516 blocked palmitate-induced NF-κB DNA-binding activity. Likewise, drug treatment inhibited the increase in IL-6 expression caused by palmitate in C2C12 and human skeletal muscle cells as well as the protein secretion of this cytokine. These findings indicate that PPARδ attenuates fatty acid-induced NF-κB activation and the subsequent development of insulin resistance in skeletal muscle cells by reducing DAG accumulation. Our results point to PPARδ activation as a pharmacological target to prevent insulin resistance.
The physiology of climate change: how potentials for acclimatization and genetic adaptation will determine ‘winners’ and ‘losers’
Authors: Somero G. N.
Published: February 2010

Physiological studies can help predict effects of climate change through determining which species currently live closest to their upper thermal tolerance limits, which physiological systems set these limits, and how species differ in acclimatization capacities for modifying their thermal tolerances. Reductionist studies at the molecular level can contribute to this analysis by revealing how much change in sequence is needed to adapt proteins to warmer temperatures — thus providing insights into potential rates of adaptive evolution — and determining how the contents of genomes — protein-coding genes and gene regulatory mechanisms — influence capacities for adapting to acute and long-term increases in temperature. Studies of congeneric invertebrates from thermally stressful rocky intertidal habitats have shown that warm-adapted congeners are most susceptible to local extinctions because their acute upper thermal limits (LT50 values) lie near current thermal maxima and their abilities to increase thermal tolerance through acclimation are limited. Collapse of cardiac function may underlie acute and longer-term thermal limits. Local extinctions from heat death may be offset by in-migration of genetically warm-adapted conspecifics from mid-latitude ‘hot spots’, where midday low tides in summer select for heat tolerance. A single amino acid replacement is sufficient to adapt a protein to a new thermal range. More challenging to adaptive evolution are lesions in genomes of stenotherms like Antarctic marine ectotherms, which have lost protein-coding genes and gene regulatory mechanisms needed for coping with rising temperature. These extreme stenotherms, along with warm-adapted eurytherms living near their thermal limits, may be the major ‘losers’ from climate change.
Challenges in predicting climate and environmental effects on vector-borne disease episystems in a changing world
Authors: Tabachnick W. J.
Published: February 2010

Vector-borne pathogens cause enormous suffering to humans and animals. Many are expanding their range into new areas. Dengue, West Nile and Chikungunya have recently caused substantial human epidemics. Arthropod-borne animal diseases like Bluetongue, Rift Valley fever and African horse sickness pose substantial threats to livestock economies around the world. Climate change can impact the vector-borne disease epidemiology. Changes in climate will influence arthropod vectors, their life cycles and life histories, resulting in changes in both vector and pathogen distribution and changes in the ability of arthropods to transmit pathogens. Climate can affect the way pathogens interact with both the arthropod vector and the human or animal host. Predicting and mitigating the effects of future changes in the environment like climate change on the complex arthropod—pathogen—host epidemiological cycle requires understanding of a variety of complex mechanisms from the molecular to the population level. Although there has been substantial progress on many fronts the challenges to effectively understand and mitigate the impact of potential changes in the environment on vector-borne pathogens are formidable and at an early stage of development. The challenges will be explored using several arthropod-borne pathogen systems as illustration, and potential avenues to meet the challenges will be presented.
Physiological climatic limits inDrosophila: patterns and implications
Authors: Hoffmann A. A.
Published: February 2010

Physiological limits determine susceptibility to environmental changes, and can be assessed at the individual, population or species/lineage levels. Here I discuss these levels in Drosophila, and consider implications for determining species susceptibility to climate change. Limits at the individual level in Drosophila depend on experimental technique and on the context in which traits are evaluated. At the population level, evidence from selection experiments particularly involving Drosophila melanogaster indicate high levels of heritable variation and evolvability for coping with thermal stresses and aridity. An exception is resistance to high temperatures, which reaches a plateau in selection experiments and has a low heritability/evolvability when temperatures are ramped up to a stressful level. In tropical Drosophila species, populations are limited in their ability to evolve increased desiccation and cold resistance. Population limits can arise from trait and gene interactions but results from different laboratory studies are inconsistent and likely to underestimate the strength of interactions under field conditions. Species and lineage comparisons suggest phylogenetic conservatism for resistance to thermal extremes and other stresses. Plastic responses set individual limits but appear to evolve slowly in Drosophila. There is more species-level variation in lower thermal limits and desiccation resistance compared with upper limits, which might reflect different selection pressures and/or low evolvability. When extremes are considered, tropical Drosophila species do not appear more threatened than temperate species by higher temperatures associated with global warming, contrary to recent conjectures. However, species from the humid tropics may be threatened if they cannot adapt genetically to drier conditions.