bluuebunny/crossref_metadata_2025 huggingface dataset:
Host-Microbe Interactions and Defense Mechanisms in the Development of Amoebic Liver Abscesses
Authors: Santi-Rocca Julien , Rigothier Marie-Christine , Guillén Nancy
Published: January 2009

Amoebiasis byEntamoeba histolyticais a major public health problem in developing countries and leads to several thousand deaths per year. The parasite invades the intestine (provoking diarrhea and dysentery) and the liver, where it forms abscesses (amoebic liver abscesses [ALAs]). The liver is the organ responsible for filtering blood coming from the intestinal tract, a task that implies a particular structure and immune features. Amoebae use the portal route and break through the sinusoidal endothelial barrier to reach the hepatic parenchyma. When faced with systemic and cell-mediated defenses, trophozoites adapt to their new environment and modulate host responses, leading to parasite survival and the formation of inflammatory foci. Cytopathogenic effects and the onset of inflammation may be caused by diffusible products originating from parasites and/or immune cells either by their secretion or by their release after cell death. Liver infection thus results from the interplay betweenE. histolyticaand hepatic cells. Despite its importance in terms of public health burden, the lack of integrated data on ALA genesis means that we have only an incomplete description of the initiation and development of hepatic amoebiasis. Here, we review the main steps of ALA development as well as the responses triggered in both the host and the parasite. Transcriptome studies highlighted parasite factors involved in adherence to human cells, cytopathogenic effects, and adaptative and stress responses. An understanding of their role in ALA development will help to unravel the host-pathogen interactions and their evolution throughout the infection.
Predicting smokers’ non-compliance with smoking restrictions in public places
Authors: Lazuras L , Eiser J R , Rodafinos A
Published: January 2009

Objective:

The present study aimed to identify the predictors of non-compliance with smoking restrictions among Greek college student smokers. Differences in attitudes to smoking bans and tobacco control policies between current smokers and non-smokers were also examined.

Methods:

Data were collected from college students (n = 229, mean (SD) age 21.27 (3.15) years). Measures included tobacco dependence, attitudes to tobacco control policies, outcome expectancy and normative beliefs.

Results:

The majority of current smokers reported non-compliance with existing restrictions. Logistic regression analysis showed that non-compliance was significantly predicted by (less) anticipated regret from tobacco-related health harm, tobacco dependence and perceived prevalence and social acceptability of smoking. Analysis of variance indicated that current non-smokers held significantly more positive attitudes to smoking bans and tobacco control policies than current smokers.

Conclusions:

Smoking was highly prevalent, and more than half of current smokers reported not complying with existing regulations in public places. Smokers’ attitudes to smoking bans and tobacco control policies did not have an effect on compliance behaviour. Future policies to promote compliance with smoking restrictions in Greece should target health-related anticipated regret, and perceived social norms.
Using a quitline plus low-cost nicotine replacement therapy to help disadvantaged smokers to quit
Authors: Miller C L , Sedivy V
Published: January 2009

Objectives:

To trial an intervention in a real-life setting to motivate low-income smokers to try to quit. The intervention under trial was the addition of subsidised nicotine replacement therapy (NRT) to a standard population quitline service.

Design:

Participants were low-income smokers, recruited “cold” via either a letter in the mail or a flyer inserted in a local newspaper. The intervention group received the usual service of multisession counselling from the quitline plus access to heavily subsidised NRT. A comparison group received the usual quitline service only. Participants were followed up at 3, 6, and 12 months. Trial participants were also compared with a sample of general callers to the quitline.

Results:

The offer of subsidised NRT recruited more than twice as many low-income smokers than the offer of the cessation service alone (intervention group n = 1000; comparison group n = 377). 63% were first-time callers to the quitline. Intervention respondents showed higher levels of nicotine dependence than comparison group respondents. Comparisons of quitting data were confounded by the differences in the respondents at baseline. 73.5% of smokers in the intervention group tried to quit compared to 61.0% in the comparison group. Unadjusted quit rates were higher in the intervention group than in the comparison group at 3 months and 6 months but not at 12 months.

Conclusions:

Disadvantaged smokers were easily engaged to call the quitline, particularly when offered subsidised NRT. Disadvantaged smokers using the quitline, with and without subsidised NRT, achieved cessation outcomes comparable to other studies of “mainstream” smokers.
General News
Authors: Ragan Mark A.
Published: January 2009

19th International Conference on Genome Informatics (GIW-2008) in Australia.
Biosynthesis of Plant Isoprenoids: Perspectives for Microbial Engineering
Authors: Kirby James , Keasling Jay D.
Published: January 2009

Isoprenoids are a large and highly diverse group of natural products with many functions in plant primary and secondary metabolism. Isoprenoids are synthesized from common prenyl diphosphate precursors through the action of terpene synthases and terpene-modifying enzymes such as cytochrome P450 monooxygenases. Many isoprenoids have important applications in areas such as human health and nutrition, and much effort has been directed toward their production in microbial hosts. However, many hurdles must be overcome in the elucidation and functional microbial expression of the genes responsible for biosynthesis of an isoprenoid of interest. Here, we review investigations into isoprenoid function and gene discovery in plants as well as the latest advances in isoprenoid pathway engineering in both plant and microbial hosts.
Short-Read Sequencing Technologies for Transcriptional Analyses
Authors: Simon Stacey A. , Zhai Jixian , Nandety Raja Sekhar , McCormick Kevin P. , Zeng Jia , Mejia Diego , Meyers Blake C.
Published: January 2009

The technological advances in DNA sequencing over the past five years have changed our approaches to gene expression analysis, fundamentally altering the basic methods used and in most cases driving a shift from hybridization-based approaches to sequencing-based approaches. Quantitative, tag-based studies of gene expression were one of the earliest applications of these next-generation technologies, but the tremendous depth of sequencing facilitates de novo transcript discovery, which replaces traditional expressed sequence tag (EST) sequencing. In addition, these technologies have created new opportunities for understanding the generation, stability, and decay of RNA and the impacts of chromatin differences on gene expression. As we review the impact of these methods on plant biology, we also mention published studies from animal systems when the methods are broadly applicable. We can anticipate that the published work over the past few years is a harbinger of much broader studies that are yet to be published and are sure to further advance our understanding of plant genomes in a field changing at a dizzying pace.
The Circadian System in Higher Plants
Authors: Harmer Stacey L.
Published: January 2009

The circadian clock regulates diverse aspects of plant growth and development and promotes plant fitness. Molecular identification of clock components, primarily in Arabidopsis, has led to recent rapid progress in our understanding of the clock mechanism in higher plants. Using mathematical modeling and experimental approaches, workers in the field have developed a model of the clock that incorporates both transcriptional and posttranscriptional regulation of clock genes. This cell-autonomous clock, or oscillator, generates rhythmic outputs that can be monitored at the cellular and whole-organism level. The clock not only confers daily rhythms in growth and metabolism, but also interacts with signaling pathways involved in plant responses to the environment. Future work will lead to a better understanding of how the clock and other signaling networks are integrated to provide plants with an adaptive advantage.
Lipopolysaccharide activates innate immune responses in murine intestinal myofibroblasts through multiple signaling pathways
Authors: Walton Kristen L. W. , Holt Lisa , Sartor R. Balfour
Published: January 2009

Myofibroblasts (MF) play an important role in intestinal wound healing. A compromised epithelial barrier exposes intestinal subepithelial MF to luminal bacterial products. However, responses of murine intestinal MF to bacterial adjuvants and potential roles of intestinal MF in innate immune responses are not well defined. Our aims in this study were to determine innate immune responses and intracellular signaling pathways of intestinal MF exposed to LPS, a prototypic Toll-like receptor (TLR) ligand. Expression of TLR4 in primary murine intestinal MF cultures was confirmed by RT-PCR and Western blotting. LPS-induced secretion of prostaglandin E2(PGE2), interleukin (IL)-6, and keratinocyte-derived chemokines (KC) was measured by ELISA. Intracellular responses to LPS were assessed by Western blotting for NF-κB p65, Iκ-Bα, Akt, p38 MAP kinase, and cyclooxygenase-2 (COX-2). LPS induced rapid phosphorylation of NF-κB p65, Akt, and p38 MAPK and degradation of Iκ-Bα. LPS induced expression of COX-2 and secretion of PGE2(2.0 ± 0.8-fold induction vs. unstimulated cells), IL-6 (6.6 ± 0.4-fold induction), and KC (12.5 ± 0.4-fold induction). Inhibition of phosphoinositide-3 (PI3)-kinase, p38 MAPK, or NF-κB pathways reduced LPS-induced PGE2, IL-6, and KC secretion. These studies show that primary murine intestinal MF respond to LPS, evidenced by activation of NF-κB, PI3-kinase, and MAPK signaling pathways and secretion of proinflammatory molecules. Inhibition of these pathways attenuated LPS-dependent PGE2, IL-6, and KC production, indicating that LPS activates MF by multiple signaling pathways. These data support the hypothesis that MF are a component of the innate immune system and may exert paracrine effects on adjacent epithelial and immune cells by responding to luminal bacterial adjuvants.
Increased susceptibility to exacerbated liver injury in hypercholesterolemic ApoE-deficient mice: potential involvement of oxysterols
Authors: Ferré Natàlia , Martínez-Clemente Marcos , López-Parra Marta , González-Périz Ana , Horrillo Raquel , Planagumà Anna , Camps Jordi , Joven Jorge , Tres Alba , Guardiola Francesc , Bataller Ramón , Arroyo Vicente , Clària Joan
Published: January 2009

The contribution of metabolic factors to the severity of liver disease is not completely understood. In this study, apolipoprotein E-deficient (ApoE−/−) mice were evaluated to define potential effects of hypercholesterolemia on the severity of carbon tetrachloride (CCl4)-induced liver injury. Under baseline conditions, hypercholesterolemic ApoE−/− mice showed increased hepatic oxidative stress (SOD activity/4-hydroxy-2-nonenal immunostaining) and higher hepatic TGF-β1, MCP-1, and TIMP-1 expression than wild-type control mice. After CCl4 challenge, ApoE−/− mice exhibited exacerbated steatosis (Oil Red O staining), necroinflammation (hematoxylin-eosin staining), macrophage infiltration (F4/80 immunohistochemistry), and fibrosis (Sirius red staining and α-smooth muscle actin immunohistochemistry) and more severe liver injury [alanine aminotransferase (ALT) and aspartate aminotransferase] than wild-type controls. Direct correlations were identified between serum cholesterol and hepatic steatosis, fibrosis, and ALT levels. These changes did not reflect the usual progression of the disease in ApoE−/− mice, since exacerbated liver injury was not present in untreated age-paired ApoE−/− mice. Moreover, hepatic cytochrome P-450 expression was unchanged in ApoE−/− mice. To explore potential mechanisms, cell types relevant to liver pathophysiology were exposed to selected cholesterol-oxidized products. Incubation of hepatocytes with a mixture of oxysterols representative of those detected by GC-MS in livers from ApoE−/− mice resulted in a concentration-dependent increase in total lipoperoxides and SOD activity. In hepatic stellate cells, oxysterols increased IL-8 secretion through a NF-κB-independent mechanism and upregulated TIMP-1 expression. In macrophages, oxysterols increased TGF-β1 secretion and MCP-1 expression in a concentration-dependent manner. Oxysterols did not compromise cell viability. Taken together, these findings demonstrate that hypercholesterolemic mice are sensitized to liver injury and that cholesterol-derived products (i.e., oxysterols) are able to induce proinflammatory and profibrogenic mechanisms in liver cells.
Reduced liver fibrosis in hypoxia-inducible factor-1α-deficient mice
Authors: Moon Jeon-OK , Welch Timothy P. , Gonzalez Frank J. , Copple Bryan L.
Published: January 2009

Liver fibrosis is characterized by excessive deposition of extracellular matrix in the liver during chronic injury. During early stages of this disease, cells begin to synthesize and secrete profibrotic proteins that stimulate matrix production and inhibit matrix degradation. Although it is clear that these proteins are important for development of fibrosis, what remains unknown is the mechanism by which chronic liver injury stimulates their production. In the present study, the hypothesis was tested that hypoxia-inducible factor-1α (HIF-1α) is activated in the liver during chronic injury and regulates expression of profibrotic proteins. To investigate this hypothesis, mice were subjected to bile duct ligation (BDL), an animal model of liver fibrosis. HIF-1α protein was increased in the livers of mice subjected to BDL by 3 days after surgery. To test the hypothesis that HIF-1α is required for the development of fibrosis, control and HIF-1α-deficient mice were subjected to BDL. Levels of type I collagen and α-smooth muscle actin mRNA and protein were increased in control mice by 14 days after BDL. These levels were significantly reduced in HIF-1α-deficient mice. Next, the levels of several profibrotic mediators were measured to elucidate the mechanism by which HIF-1α promotes liver fibrosis. Platelet-derived growth factor (PDGF)-A, PDGF-B, and plasminogen activator inhibitor-1 mRNA levels were increased to a greater extent in control mice subjected to BDL compared with HIF-1α-deficient mice at 7 and 14 days after BDL. Results from these studies suggest that HIF-1α is a critical regulator of profibrotic mediator production during the development of liver fibrosis.
Effects of brain stem cholecystokinin-8s on gastric tone and esophageal-gastric reflex
Authors: Holmes Gregory M. , Tong Melissa , Travagli R. Alberto
Published: January 2009

The actions of cholecystokinin (CCK) on gastrointestinal functions occur mainly via paracrine effects on peripheral sensory vagal fibers, which engage vago-vagal brain stem circuits to convey effector responses back to the gastrointestinal tract. Recent evidence suggests, however, that CCK also affects brain stem structures directly. Many electrophysiological studies, including our own, have shown that brain stem vagal circuits are excited by sulfated CCK (CCK-8s) directly, and we have further demonstrated that CCK-8s induces a remarkable degree of plasticity in GABAergic brain stem synapses. In the present study, we used fasted, anesthetized Sprague-Dawley rats to investigate the effects of brain stem administration of CCK-8s on gastric tone before and after activation of the esophageal-gastric reflex. CCK-8s microinjected in the dorsal vagal complex (DVC) or applied on the floor of the fourth ventricle induced an immediate and transient decrease in gastric tone. Upon recovery of gastric tone to baseline values, the gastric relaxation induced by esophageal distension was attenuated or even reversed. The effects of CCK-8s were antagonized by vagotomy or fourth ventricular, but not intravenous, administration of the CCK-A antagonist lorglumide, suggesting a central, not peripheral, site of action. The gastric relaxation induced by DVC microinjection of CCK-8s was unaffected by pretreatment with systemic bethanecol but was completely blocked by NG-nitro-l-arginine methyl ester, suggesting a nitrergic mechanism of action. These data suggest that 1) brain stem application of CCK-8s induces a vagally mediated gastric relaxation; 2) the CCK-8s-induced gastric relaxation is mediated via activation of nonadrenergic, noncholinergic pathways; and 3) CCK-8s reverses the esophageal-gastric reflex transiently.
Infliximab and the TNF-α system
Authors: Ebert Ellen C.
Published: January 2009

Infliximab, a chimeric monoclonal antibody against TNF-α, is efficacious in Crohn's disease (CD) and rheumatoid arthritis (RA). Its main mechanism of action is thought to be the induction of apoptosis. The present study evaluates in detail the effects of infliximab on the TNF-α system using peripheral blood monocytes and T cells as well as lamina propria lymphocytes from normal individuals and patients with CD, ulcerative colitis, and RA. Lymphocytes were studied in the resting state in the absence of strong stimuli that may obscure subtle findings. Infliximab did not change the numbers of viable cells. Rather, it caused monocytes to increase their release of soluble TNFR2, which serves to neutralize TNF-α, potentiating the action of infliximab. It reduced TNFR2 expression, thereby decreasing TNF-α responsiveness. These changes were due to upregulated production of TNFR2 rather than increased shedding. Infliximab did not cause rebound production of TNF-α transcripts that would counteract its effects. It specifically enhanced production of IL-10 but not proinflammatory cytokines secreted by leukocytes, thereby promoting an anti-inflammatory microenvironment. In addition, infliximab caused a rise in c-Jun amino-terminal kinase phosphorylation by monocytes. Thus infliximab manipulates the TNF-α system to promote its anti-TNF-α effects.
20-HETE increases survival and decreases apoptosis in pulmonary arteries and pulmonary artery endothelial cells
Authors: Dhanasekaran Anuradha , Bodiga Sreedhar , Gruenloh Stephanie , Gao Ying , Dunn Laurel , Falck John R. , Buonaccorsi J. Noelle , Medhora Meetha , Jacobs Elizabeth R.
Published: January 2009

20-Hydroxyeicosatetraenoic acid (20-HETE) is an endogenous cytochrome P-450 product present in vascular smooth muscle and uniquely located in the vascular endothelium of pulmonary arteries (PAs). 20-HETE enhances reactive oxygen species (ROS) production of bovine PA endothelial cells (BPAECs) in an NADPH oxidase-dependent manner and is postulated to promote angiogenesis via activation of this pathway in systemic vascular beds. We tested the capacity of 20-HETE or a stable analog of this compound, 20-hydroxy-eicosa-5( Z),14( Z)-dienoic acid, to enhance survival and protect against apoptosis in BPAECs stressed with serum starvation. 20-HETE produced a concentration-dependent increase in numbers of starved BPAECs and increased 5-bromo-2′-deoxyuridine incorporation. Caspase-3 activity, nuclear fragmentation studies, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays supported protection from apoptosis and enhanced survival of starved BPAECs treated with a single application of 20-HETE. Protection from apoptosis depended on intact NADPH oxidase, phosphatidylinositol 3 (PI3)-kinase, and ROS production. 20-HETE-stimulated ROS generation by BPAECs was blocked by inhibition of PI3-kinase or Akt activity. These data suggest 20-HETE-associated protection from apoptosis in BPAECs required activation of PI3-kinase and Akt and generation of ROS. 20-HETE also protected against apoptosis in BPAECs stressed by lipopolysaccharide, and in mouse PAs exposed to hypoxia reoxygenation ex vivo. In summary, 20-HETE may afford a survival advantage to BPAECs through activation of prosurvival PI3-kinase and Akt pathways, NADPH oxidase activation, and NADPH oxidase-derived superoxide.
Heat shock protein 90-eNOS interactions mature with postnatal age in the pulmonary circulation of the piglet
Authors: Aschner Judy L. , Zeng Heng , Kaplowitz Mark R. , Zhang Yongmei , Slaughter James C. , Fike Candice D.
Published: January 2009

Binding of endothelial nitric oxide synthase (eNOS) to the chaperone protein, Hsp90, promotes coupled eNOS synthetic activity. Using resistance level pulmonary arteries (PRA) from 2-day-, 5- to 7-day-, and 12-day-old piglets, we tested the hypothesis that Hsp90-eNOS interactions are developmentally regulated in the early neonatal period. PRA were isolated for coimmunoprecipitation and immunoblot analyses or cannulated for continuous diameter measurements using the pressurized myography technique. NOS inhibition caused less constriction in PRA from 2-day- compared with 5- to 7-day- and 12-day-old piglets. No age-related differences were found in dilation responses to an NO donor or in protein expression of Hsp90, phospho-eNOS (Ser1177), Akt, phospho-Akt, or caveolin-1. Compared with the older animals, PRA from 2-day-old piglets had higher total eNOS expression but displayed less binding of eNOS to Hsp90 and Akt. Hsp90 antagonism with radicicol induced greatest constriction in PRA from 12-day-old piglets. ACh stimulation caused dilation in PRA from 5- to 7-day- and 12-day-old but not 2-day-old animals, despite rapid and equivalent ACh-mediated eNOS phosphorylation (Ser1177) in all three age groups. Hsp90 inhibition abolished ACh-mediated dilation in PRA from the older piglets. ACh failed to stimulate Hsp90-eNOS binding in 2-day-old but induced a significant increase in Hsp90-eNOS coimmunoprecipitation in PRA from the older age groups, which was blocked by Hsp90 antagonism. We conclude that physical interactions between Hsp90 and eNOS mature over the first weeks of life, likely contributing to the postnatal fall in pulmonary vascular resistance and changes in agonist-induced pulmonary vascular responses characteristic of the early neonatal period.
Carbon dioxide inhalation causes pulmonary inflammation
Authors: Abolhassani Mohammad , Guais Adeline , Chaumet-Riffaud Philippe , Sasco Annie J. , Schwartz Laurent
Published: January 2009

The aim of this study was to assess whether one of the most common poisons of cellular respiration, i.e., carbon dioxide, is proinflammatory. CO2 is naturally present in the atmosphere at the level of 0.038% and involved in numerous cellular biochemical reactions. We analyzed in vitro the inflammation response induced by exposure to CO2 for 48 h (0–20% with a constant O2 concentration of 21%). In vivo mice were submitted to increasing concentrations of CO2 (0, 5, 10, and 15% with a constant O2 concentration of 21%) for 1 h. The exposure to concentrations above 5% of CO2 resulted in the increased transcription (RNase protection assay) and secretion (ELISA) of proinflammatory cytokines [macrophage inflammatory protein-1α (MIP-1α), MIP-1β, MIP-2, IL-8, IL-6, monocyte chemoattractant protein-1, and regulated upon activation, normal T cell expressed, and, presumably, secreted (RANTES)] by epithelial cell lines HT-29 or A549 and primary pulmonary cells retrieved from the exposed mice. Lung inflammation was also demonstrated in vivo by mucin 5AC-enhanced production and airway hyperreactivity induction. This response was mostly mediated by the nuclear translocation of p65 NF-κB, itself a consequence of protein phosphatase 2A (PP2A) activation. Short inhibiting RNAs (siRNAs) targeted toward PP2Ac reversed the effect of carbon dioxide, i.e., disrupted the NF-κB activation and the proinflammatory cytokine secretion. In conclusion, this study strongly suggests that exposure to carbon dioxide may be more toxic than previously thought. This may be relevant for carcinogenic effects of combustion products.
Different contribution of muscle and liver lipid metabolism to endurance capacity and obesity susceptibility of mice
Authors: Haramizu Satoshi , Nagasawa Azumi , Ota Noriyasu , Hase Tadashi , Tokimitsu Ichiro , Murase Takatoshi
Published: January 2009

We investigated strain differences in whole body energy metabolism, peripheral lipid metabolism, and energy metabolism-related gene expression and protein levels in BALB/c, C57BL/6J, and A/J mice to evaluate the relationship between endurance capacity, susceptibility to diet-induced obesity, and differences in lipid metabolism in muscle and liver. A high-fat diet significantly increased body weight and fat weight in C57BL/6J mice, but not in BALB/c and A/J mice. The endurance capacity of BALB/c mice was 52% greater than that of C57BL/6J mice and 217% greater than that of A/J mice. The respiratory exchange ratio was lowest in BALB/c mice, higher in C57BL/6J mice, and highest in A/J mice, which inversely correlated with the endurance capacity and fatty acid β-oxidation activity in the muscle. Plasma lactate levels measured immediately after exercise were lowest in BALB/c mice and highest in A/J mice, although there was no difference under resting conditions, suggesting that carbohydrate breakdown is suppressed by enhanced fat utilization during exercise in BALB/c mice. On the other hand, the body weight increase induced by high-fat feeding was related to a reduced whole body energy expenditure, higher respiratory quotient, and lower fatty acid β-oxidation activity in the liver. In addition, β-oxidation activity in the muscle and liver roughly paralleled the mRNA and protein levels of lipid metabolism-related molecules, such as peroxisome proliferator-activated receptor and medium-chain acyl-CoA dehydrogenase, in each tissue. These findings indicate that genetically determined basal muscle and liver lipid metabolism and responsiveness to exercise influence physical performance and obesity susceptibility.
Spinal P2X receptor modulates muscle pressor reflex via glutamate
Authors: Li Jianhua , Lu Jian , Gao Zhaohui , Koba Satoshi , Xing Jihong , King Nicholas , Sinoway Lawrence
Published: January 2009

Static contraction of skeletal muscle evokes reflex increases in blood pressure and heart rate. Previous studies showed that P2X receptors located at the dorsal horn of the spinal cord play a role in modulating the muscle pressor reflex. P2X stimulation can alter release of the excitatory amino acid, glutamate (Glu). In this report, we tested the hypothesis that stimulation of P2X receptors enhances the concentrations of Glu ([Glu]) in the dorsal horn, and that blocking P2X receptors attenuates contraction-induced Glu increases and the resultant reflex pressor response. Contraction was elicited by electrical stimulation of the L7and S1ventral roots of 14 cats. Glu samples were collected from microdialysis probes inserted in the L7level of the dorsal horn of the spinal cord, and dialysate [Glu] was determined using the HPLC method. First, microdialyzing α,β-methylene ATP (0.4 mM) into the dorsal horn significantly increased [Glu]. In addition, contraction elevated [Glu] from baseline of 536 ± 53 to 1,179 ± 192 nM ( P < 0.05 vs. baseline), and mean arterial pressure by 39 ± 8 mmHg in the control experiment. Microdialyzing the P2X receptor antagonist pyridoxal phosphate-6-azophenyl-2′,4′-disulfonic acid (10 mM) into the dorsal horn attenuated the contraction induced-Glu increase (610 ± 128 to 759 ± 147 nM; P > 0.05) and pressor response (16 ± 3 mmHg, P < 0.05 vs. control). Our findings demonstrate that P2X modulates the cardiovascular responses to static muscle contraction by affecting the release of Glu in the dorsal horn of the spinal cord.
Mental fatigue impairs physical performance in humans
Authors: Marcora Samuele M. , Staiano Walter , Manning Victoria
Published: January 2009

Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity. Although the impact of mental fatigue on cognitive and skilled performance is well known, its effect on physical performance has not been thoroughly investigated. In this randomized crossover study, 16 subjects cycled to exhaustion at 80% of their peak power output after 90 min of a demanding cognitive task (mental fatigue) or 90 min of watching emotionally neutral documentaries (control). After experimental treatment, a mood questionnaire revealed a state of mental fatigue ( P = 0.005) that significantly reduced time to exhaustion (640 ± 316 s) compared with the control condition (754 ± 339 s) ( P = 0.003). This negative effect was not mediated by cardiorespiratory and musculoenergetic factors as physiological responses to intense exercise remained largely unaffected. Self-reported success and intrinsic motivation related to the physical task were also unaffected by prior cognitive activity. However, mentally fatigued subjects rated perception of effort during exercise to be significantly higher compared with the control condition ( P = 0.007). As ratings of perceived exertion increased similarly over time in both conditions ( P < 0.001), mentally fatigued subjects reached their maximal level of perceived exertion and disengaged from the physical task earlier than in the control condition. In conclusion, our study provides experimental evidence that mental fatigue limits exercise tolerance in humans through higher perception of effort rather than cardiorespiratory and musculoenergetic mechanisms. Future research in this area should investigate the common neurocognitive resources shared by physical and mental activity.
Carnosine loading and washout in human skeletal muscles
Authors: Baguet Audrey , Reyngoudt Harmen , Pottier Andries , Everaert Inge , Callens Stefanie , Achten Eric , Derave Wim
Published: January 2009

Carnosine (β-alanyl-l-histidine) is present in high concentrations in human skeletal muscles. The oral ingestion of β-alanine, the rate-limiting precursor in carnosine synthesis, has been shown to elevate the muscle carnosine content both in trained and untrained humans. Little human data exist about the dynamics of the muscle carnosine content, its metabolic regulation, and its dependence on muscle fiber type. The present study aimed to investigate in three skeletal muscle types the supplementation-induced amplitude of carnosine synthesis and its subsequent elimination on cessation of supplementation (washout). Fifteen untrained males participated in a placebo-controlled double-blind study. They were supplemented for 5–6 wk with either 4.8 g/day β-alanine or placebo. Muscle carnosine was quantified in soleus, tibialis anterior, and medial head of the gastrocnemius by proton magnetic resonance spectroscopy (MRS), before and after supplementation and 3 and 9 wk into washout. The β-alanine supplementation significantly increased the carnosine content in soleus by 39%, in tibialis by 27%, and in gastrocnemius by 23% and declined postsupplementation at a rate of 2–4%/wk. Average muscle carnosine remained increased compared with baseline at 3 wk of washout (only one-third of the supplementation-induced increase had disappeared) and returned to baseline values within 9 wk at group level. Following subdivision into high responders (+55%) and low responders (+15%), washout period was 15 and 6 wk, respectively. In the placebo group, carnosine remained relatively constant with variation coefficients of 9–15% over a 3-mo period. It can be concluded that carnosine is a stable compound in human skeletal muscle, confirming the absence of carnosinase in myocytes. The present study shows that washout periods for crossover designs in supplementation studies for muscle metabolites may sometimes require months rather than weeks.
Aging, exercise, and muscle protein metabolism
Authors: Koopman René , van Loon Luc J. C.
Published: January 2009

Aging is accompanied by a progressive loss of skeletal muscle mass and strength, leading to the loss of functional capacity and an increased risk of developing chronic metabolic disease. The age-related loss of skeletal muscle mass is attributed to a disruption in the regulation of skeletal muscle protein turnover, resulting in an imbalance between muscle protein synthesis and degradation. As basal (fasting) muscle protein synthesis rates do not seem to differ substantially between the young and elderly, many research groups have started to focus on the muscle protein synthetic response to the main anabolic stimuli, i.e., food intake and physical activity. Recent studies suggest that the muscle protein synthetic response to food intake is blunted in the elderly. The latter is now believed to represent a key factor responsible for the age-related decline in skeletal muscle mass. Physical activity and/or exercise stimulate postexercise muscle protein accretion in both the young and elderly. However, the latter largely depends on the timed administration of amino acids and/or protein before, during, and/or after exercise. Prolonged resistance type exercise training represents an effective therapeutic strategy to augment skeletal muscle mass and improve functional performance in the elderly. The latter shows that the ability of the muscle protein synthetic machinery to respond to anabolic stimuli is preserved up to very old age. Research is warranted to elucidate the interaction between nutrition, exercise, and the skeletal muscle adaptive response. The latter is needed to define more effective strategies that will maximize the therapeutic benefits of lifestyle intervention in the elderly.
Insulin Resistance Markers in Children
Authors: Eyzaguirre Francisca , Mericq Verónica
Published: January 2009

The prevalence of obesity among children and adolescents is progressively increasing around the world. One of the important consequences of obesity is the development of insulin resistance (IR). This condition has a multifactorial pathogenesis and is associated with cardiovascular risk, diabetes, hypertension, polycystic-ovary syndrome and a shorter lifespan. IR during childhood may be diagnosed by physical examination or there may be clues in the histories of the patient and his/her family. When IR is suspected, tests on a blood sample (which are more reliable) are recommended. Most of the biochemical markers have been well defined in adults, but appropriate reference data for children are still lacking. Here we discuss the usefulness of various currently known biochemical markers to evaluate insulin sensitivity (homeostatic model assessment, the quantitative insulin sensitivity check index, the oral glucose tolerance test, Matsuda method and the whole-body insulin resistance index), hormones (leptin, adiponectin, resistin, glucocorticoids, the insulin-like growth factor-1-binding protein/growth hormone axis, ghrelin, sex hormone-binding globulin and retinol-binding protein-4) and inflammatory markers (C-reactive protein, IL-6, intercellular adhesion molecule-1, vascular adhesion molecule-1 and E-selectin), which can be used in the diagnosis of IR in children.
Inhibin A Production after Gonadotropin Stimulus: A New Method to Detect Ovarian Tissue in Ovotesticular Disorder of Sex Development
Authors: Steinmetz L. , Rocha M.N. , Longui C.A. , Damiani D. , Dichtchekenian V. , Setian N. , Damiani D.
Published: January 2009

Background/Aims: While laboratory methods for the detection of testicular tissue are well standardized, currently there is no available test to demonstrate the presence of ovarian tissue. We evaluated the effectiveness of gonadal stimulation with luteinizing hormone (LH)/follicle-stimulating hormone (FSH) for the detection of ovarian tissue in patients with disorders of sex development (DSD). Methods: Ten patients with congenital adrenal hyperplasia (CAH) as ovarian-positive controls, 10 with cryptorchidism (ovarian-negative controls), 13 patients with DSD of no defined etiology and 7 patients with ovotesticular DSD (true hermaphroditism, TH) were included in the study. They underwent a daily injection of both LH and FSH on 3 consecutive days. LH, FSH, estradiol, testosterone and inhibin A were measured before treatment, 24 h after the 1st dose and 24 h after the 3rd dose. Results: Estradiol increased in all CAH and TH patients, with a median value of 155.1 and 92.6 pg/ml, respectively, after the 3rd injection. Inhibin A also increased in all CAH and TH patients, with a median value of 70.4 and 32.2 pg/ml, respectively, after the 3rd injection. There was no change in these hormones in the other groups. Conclusion: The LH/FSH stimulation test might be a useful method to detect the presence of ovarian tissue.
Three Novel IGFALS Gene Mutations Resulting in Total ALS and Severe Circulating IGF-I/IGFBP-3 Deficiency in Children of Different Ethnic Origins
Authors: Fofanova-Gambetti Olga V. , Hwa Vivian , Kirsch Susan , Pihoker Catherine , Chiu Harvey K. , Högler Wolfgang , Cohen Laurie E. , Jacobsen Christina , Derr Michael A. , Rosenfeld Ron G.
Published: January 2009

Background/Aims: To date, four mutations in the IGFALS gene have been reported. We now describe two children of different ethnic background with total acid-labile subunit (ALS) and severe circulating IGF-I/IGFBP-3 deficiencies resulting from three novel mutations in the IGFALS gene. Patients/Methods: Serum and DNA of patients were analyzed. Results: Case 1 is a 12-year-old boy of Mayan origin. Case 2 is a 5-year-old girl of Jewish/Eastern European (Polish, Russian, Austrian-Hungarian)/Icelandic/European (French, English) ancestry. The reported cases had moderate short stature (–2.91 and –2.14 SDS, respectively), nondetectable serum ALS and extremely low serum concentrations of IGF-I and IGFBP-3. Case 1 harbored a novel homozygous 1308_1316 dup9 mutation in a highly conserved leucine-rich repeat (LRR) 17 motif of exon 2, representing an in-frame insertion of 3 amino acids, LEL. Case 2 harbored a novel heterozygous C60S/L244F mutation in exon 2, located within a highly conserved LRR 1 and LRR 9, respectively. Conclusions: The identification of additional novel IGFALS mutations, resulting in severe IGF-I/IGFBP-3 and ALS deficiencies, supports IGFALS as a candidate gene of the GH/IGF system, implicated in the pathogenesis of primary IGF deficiency, and represents an important part of its differential diagnosis.
Effects of Changes in Alveolar Ventilation on Isoflurane Arterial Blood Concentration and Its Uptake into the Human Body
Authors: Lu Chih-Cherng , Lin Tso-Chou , Yu Mu-Hsien , Chen Ta-Liang , Lin Chung-Yuan , Chiang Joseph S. , Ho Shung-Tai
Published: January 2009

We investigated whether minute alveolar ventilation affects isoflurane concentration in arterial blood and uptake of isoflurane into the body. Thirty female patients scheduled to undergo elective gynecological surgery were randomly assigned to one of three groups: i.e. hyperventilation, normal ventilation and hypoventilation. Inspiratory (CIiso) and end-tidal (CEiso) concentrations of isoflurane were measured by infrared analysis, and arterial blood isoflurane concentration (Aiso) was analyzed by gas chromatography. Cardiac index was measured by Doppler ultrasonography. The body uptake of isoflurane was determined by multiplying alveolar ventilation by the gradient of CIiso–CEiso. Aiso was highest in the hyperventilation group (significant), followed by the normal ventilation and hypoventilation groups, during the 40-min study. During the first 10 min of the study, the slope of the Aiso-over-time curve was highest in the hyperventilation group, followed by the normal ventilation group and the hypoventilation group. During the second half of the study (20–40 min), the slope Aiso-over-time curve did not differ among the three groups. Changes in ventilation affected the concentration of isoflurane in arterial blood but did not significantly alter the uptake of it during the last 20 min of the study. The change of alveolar ventilation altered the speed of functional residual capacity wash-in by isoflurane, which was the integral factor influencing Aiso and body uptake of isoflurane.
Differential Expression of Matrix Metalloproteinases and Tissue Inhibitors and Extracellular Matrix Remodeling in Aortic Regurgitant Hearts
Authors: Truter Sharada L. , Catanzaro Daniel F. , Supino Phyllis G. , Gupta Anuj , Carter John , Herrold Edmund M. , Dumlao Themy F. , Borer Jeffrey S.
Published: January 2009

Objectives: Myocardial fibrosis in experimental aortic regurgitation (AR) features abnormal fibronectin with normal collagen content, but the relevant degradative processes have not been assessed. Methods: To elucidate these degradative processes, mRNA (Northern) and protein levels (Western) of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), as well as MMP activity (zymography), were measured in cardiac fibroblasts (CF) from New Zealand white rabbits with experimental AR paired with normals (NL). Collagen and fibronectin were quantified by immunohistochemical staining. Results: In AR CF versus NL CF, MMP-2 and -14 mRNA and protein were increased (both p < 0.005), while TIMPs 1–3 were slightly decreased (p < 0.05–0.005; TIMP-4 undetectable). Gelatinase activity in AR CF was 1.7 times that in NL CF (p < 0.005); fibronectinase activity was unaffected. The Jun N-terminal kinase (JNK) inhibitor SP600125 suppressed MMP-2 protein (0.4-fold, p < 0.05) and mRNA (0.7-fold, p < 0.005) in AR CF; MMP-2 levels in NL CF were unaffected. AR MMP-9 mRNA, protein and activity were low and indistinguishable from NL. In left ventricular tissue, fibronectin was increased 1.9-fold (AR vs. NL, p < 0.05). Total AR collagen was indistinguishable from NL, but the collagen III to collagen I isoform ratio decreased (0.4-fold, p < 0.05). Conclusions: Collagen is relatively deficient in AR fibrosis, due at least in part to upregulated MMPs and downregulated TIMPs; fibronectinase is unaltered. JNK-dependent regulation may stimulate both MMP-2 and fibronectin expression in AR, providing a potential therapeutic target.
Lectin UEA-I-Binding Proteins Are Specifically Increased in the Squamous Epithelium of Patients with Barrett’s Esophagus
Authors: Neumann Helmut , Wex Thomas , Mönkemüller Klaus , Vieth Michael , Fry Lucía C. , Malfertheiner Peter
Published: January 2009

Background: Chronic gastritis and esophagitis are associated with changes in mucosal glycosylation patterns. Lectins represent a group of specific carbohydrate binding proteins that can be used as sensitive tools for the analysis of glycosylation patterns. Aim: To investigate the binding patterns of lectins Ulex europaeus agglutinin-I (UEA-I), Dolichos biflorus agglutinin (DBA), Helix pomatia agglutinin (HPA) and peanut agglutinin (PNA) at the gastroesophageal junction in nonerosive (NERD), erosive reflux disease (ERD) and Barrett’s esophagus (BE). Methods: One hundred and twenty-two patients (female n = 53; male n = 69; controls n = 28; NERD n = 36; ERD n = 24 and BE n = 34) were included in this study. The binding patterns of lectins were examined immunohistochemically at the squamocolumnar junction, in squamous epithelium and columnar-lined epithelium. Staining patterns of lectins were semiquantitatively evaluated using an immunohistochemical score and the data were analyzed using non-parametric tests. Results: BE, as compared to the controls, was associated with specific lectin-binding patterns: lectin binding of UEA-I and DBA were significantly decreased at the superficial (p = 0.012; p = 0.00036, respectively) and at the deep glandular body (p = 0.045; p = 0.055, respectively). Comparisons of lectin-staining scores between GERD and BE revealed significant increases of UEA-I in both the stratum superficiale (p = 0.0155) and stratum spinosum (p = 0.0048) of SE in patients with BE. Notable, this change was specific for patients with BE, while no difference was observed between patients with GERD and controls. Conclusion: We found two major types of lectin-binding patterns. First, lectin-binding characteristics associated with GERD in general, and second, lectin-binding patterns which were specific for BE. Lectin UEA-I-binding proteins were specifically increased in the squamous epithelium of patients with BE. Thus, UEA-I may serve as a potential marker for BE, especially in patients with short segment BE.
Cognitive Impairment and Dementia in Elderly People Living in Rural Benin, West Africa
Authors: Guerchet Maëlenn , Houinato Dismand , Paraiso Moussiliou Noël , von Ahsen Nicolas , Nubukpo Philippe , Otto Markus , Clément Jean-Pierre , Preux Pierre-Marie , Dartigues Jean-François
Published: January 2009

Background/Aims: Dementia is increasing as a priority public health problem because of the ageing of the world population. Our goal was to estimate dementia and cognitive impairment prevalence in an elderly population of rural Benin. Methods: In a door-to-door survey, elderly people aged 65 years and above were screened using the Community Screening Interview for Dementia and the Five-Word Test. Results: The prevalence of cognitive impairment was 10.4% and that of dementia was 2.6%. Age, current depressive disorder and absence of the APOE ε2 allele were significantly associated with cognitive impairment. Conclusion: Prevalence of dementia and cognitive impairment appears to be lower in this study than in developed countries.
Effects of Very-Low-Carbohydrate (Horsemeat- or Beef-Based) Diets and Restricted Feeding on Weight Gain, Feed and Energy Efficiency, as well as Serum Levels of Cholesterol, Triacylglycerol, Glucose, Insulin and Ketone Bodies in Adult Rats
Authors: Kim Jae-Youn , Yang Young-Hoon , Kim Choong-Nam , Lee Chong-Eon , Kim Kyu-Il
Published: January 2009

Background/Aims: The beneficial or harmful effect of the low-carbohydrate (low-carb), high-protein, high-fat diet (Atkins diet) has not been clearly demonstrated. We determined the effect of a low-carb diet and restricted feeding (70% ad libitum intake) on serum levels of cholesterol, triacylglycerol, glucose, ketone bodies and insulin in rats. Methods: In experiment 1, each of 4 groups with 10 adult rats was assigned to a high-carb diet (AIN-93G) + ad libitum intake or restricted feeding, or a low-carb diet (53% horsemeat) + ad libitum intake or restricted feeding (2 × 2 factorial). In experiment 2, each of 3 groups with 10 adult rats was assigned to a control (AIN-93G) or low-carb diets (53% beef or horsemeat). Results: Restricted feeding and the low-carb diet reduced (p < 0.01) serum triacylglycerol compared with ad libitum intake and the AIN-93G diet, respectively (experiment 1). The dietary effect on serum total cholesterol, high-density or low-density lipid cholesterol appeared to be inconsistent, but restricted feeding increased the low-density lipoprotein cholesterol level. The serum ketone body level was increased by the low-carb diet compared with AIN-93G (experiment 2). Conclusion: Restricted feeding and a low-carb diet are beneficial for alleviating cardiovascular disease risk factors, and their effects are additive, restricted feeding being more pronounced.
Correlation of FcγRIIa (CD32) Polymorphism and IgG Antibody Subclasses in Hemolytic Disease of Newborn
Authors: Wu QiangJu , Zhang Yan , Liu MengLi , Wang Bo , Liu Sheng , He Chen
Published: January 2009

ABO-HDN is a common disease of newborn in China and currently there is no satisfactory method to predict it in the antepartum period. It has been reported that FcγRIIa (CD32) genotype is associated with both infectious diseases induced by bacteria and parasitemia. There is a relationship between IgG subclass and RH-HDN. To study the pathogenesis of ABO-HDN and to find reliable method to diagnose ABO-HDN, we investigated the polymorphism of FcγRIIa (CD32) and distribution of IgG subclass in infants with ABO-HDN and their mothers by polymerase chain reaction or ELISA assay. We observed that the frequency of HH131 ge- notype is lower in infants with ABO-HDN than in controls (p < 0.01), while the frequency of HR131 genotype is higher in ABO-HDN infants than that in controls (p < 0.01). The genotype HR131 and concentrations of IgG1 and IgG3 are significantly correlated with ABO-HDN. Our results demonstrated, for the first time, that there is a correlation between ABO-HDN and CD32, and different IgG subclass distribution. Our study may contribute to the development of an early diagnostic method for HDN.