bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct Ex Vivo Analyses of HLA-DR1 Transgenic Mice Reveal an Exceptionally Broad Pattern of Immunodominance in the Primary HLA-DR1-Restricted CD4 T-Cell Response to Influenza Virus Hemagglutinin
Authors: Richards Katherine A. , Chaves Francisco A. , Krafcik Frederick R. , Topham David J. , Lazarski Christopher A. , Sant Andrea J.
Published: May 2007

The recent threat of an avian influenza pandemic has generated significant interest in enhancing our understanding of the events that dictate protective immunity to influenza and in generating vaccines that can induce heterosubtypic immunity. Although antigen-specific CD4 T cells are known to play a key role in protective immunity to influenza through the provision of help to B cells and CD8 T cells, little is known about the specificity and diversity of CD4 T cells elicited after infection, particularly those elicited in humans. In this study, we used HLA-DR transgenic mice to directly and comprehensively identify the specificities of hemagglutinin (HA)-specific CD4 T cells restricted to a human class II molecule that were elicited following intranasal infection with a strain of influenza virus that has been endemic in U.S. human populations for the last decade. Our results reveal a surprising degree of diversity among influenza virus-specific CD4 T cells. As many as 30 different peptides, spanning the entire HA protein, were recognized by CD4 T cells, including epitopes genetically conserved among H1, H2, and H5 influenza A viruses. We also compared three widely used major histocompatibility class II algorithms to predict HLA-DR binding peptides and found these as yet inadequate for identifying influenza virus-derived epitopes. The results of these studies offer key insights into the spectrum of peptides recognized by HLA-DR-restricted CD4 T cells that may be the focus of immune responses to infection or to experimental or clinical vaccines in humans.
Medical report from the 2006 FIFA World Cup Germany
Authors: Dvorak Jiri , Junge Astrid , Grimm Katharina , Kirkendall Donald
Published: May 2007

Objective:

To continue the injury surveillance of FIFA-sponsored football tournaments and report on other medical aspects of the 2006 FIFA World Cup.

Design:

Prospective epidemiological injury surveillance and descriptive summary of additional medical aspects.

Setting:

Major international football tournament.

Participants:

National team players, doctors and referees at the 2006 FIFA World Cup Germany.

Main outcome measures:

Injury type, location and rate.

Results:

145 injuries were reported for the 64 matches of the 2006 FIFA World Cup Germany—an overall injury rate of 68.7 per 1000 match hours (95% CI 57.5 to 79.9) or 2.3 injuries per match, in comparison with 2.7 injuries per match in the 2002 FIFA World Cup (p = NS). Physical examinations before participation uncovered no hidden cardiovascular problems. Once the tournament started, no referees were unable to complete their duties. There were no positive doping tests.

Conclusions:

The injury rate for this World Cup was below that of 2002, but consistent with the overall injury rate per match since data collection began in 1998. There continues to be no evidence of systematic doping in international football.
Career-ending injuries to professional jockeys in British horse racing (1991–2005)
Authors: Balendra G , Turner M , McCrory P
Published: May 2007

Background:

It has been previously shown that professional jump and flat racing jockeys suffer a high incidence of injury as a consequence of their profession. This paper specifically examines career-ending injuries to professional jockeys in Great Britain.

Aims:

To investigate career-ending injuries in professional jockeys.

Method:

Analysis of prospectively collected injury database on professional jockeys.

Results:

The majority of injuries in this study occurred to the head, shoulder or torso. Fractures were the most common type of injury that led to a decision to end a career, followed by neurological injury to the head and/or spine.

Conclusion:

Injuries to the head are the most common career-ending injuries, and consideration of injury counter measures could be an important strategy in equestrian sports.
Think tank on school-aged children: nutrition and physical activity to prevent the rise in obesity
Authors: Mendelson Rena
Published: May 2007

The rise in childhood obesity has generated concern across a range of sectors. Stakeholders and experts in the area of children’s health met at a Think Tank in Toronto organized by the Canadian Council for Food and Nutrition and the Program in Food Safety, Nutrition, and Regulatory Affairs at the University of Toronto to discuss the current evidence in place to inform the development of school policies to reduce childhood obesity. Although there is some evidence to suggest that school interventions may reduce obesity in children, there are other examples of programs that have had very little impact. The role of parents in the development of healthy eating and physical activity patterns is critical from the earliest stages of life and warrants further attention. Delegates agreed that we need ongoing input of experts and leaders from all sectors and fields to help us to effectively promote healthy lifestyles at schools and within the home, while respecting each child's need for safety, security, and respect.
No difference in insulin sensitivity between healthy postmenopausal women with or without sarcopenia: a pilot study
Authors: Goulet Eric D.B. , Lord Christine , Chaput Jean-Philippe , Aubertin-Leheudre Mylène , Brochu Martin , Dionne Isabelle J.
Published: May 2007

Insulin plays a pivotal role in skeletal muscle protein metabolism and its action decreases with age. A loss of muscle mass, termed sarcopenia, also occurs with age. The age-associated decline in insulin sensitivity (IS) may negatively alter muscle protein metabolism and, therefore, be implicated in the aetiology of sarcopenia. However, no studies have yet compared the level of IS between older individuals with or without sarcopenia. Thus, in this study, we compared the IS of 20 class I sarcopenics (CIS), 8 class II sarcopeniscs (CIIS), and 16 non-sarcopenics (NS), among a group of otherwise healthy, non-obese, postmenopausal women. IS was estimated with the quantitative IS check index (QUICKI). Muscle mass index (MMI), which was used to determine sarcopenia, was calculated as follows: (appendicular  muscle  mass × 1.19) – 1.01/h2, where h = height. Fat-free mass (FFM), fat mass (FM), and trunk FM (TFM) were measured by dual-energy X-ray absorptiometry. Accelerometry and indirect calorimetry were used to estimate resting (REE), daily (DEE), and physical activity (PAEE) energy expenditure. A 3 d food record was used to determine total energy, protein (animal and vegetal), and carbohydrate intakes. As expected, MMI and FFM differed significantly among groups. However, no significant differences were found among groups for IS, FM, TFM, REE, DEE, PAEE, or total energy, protein (both animal and vegetable), and carbohydrate intakes. Using QUICKI, a surrogate measure of IS, the present results suggest that the action of insulin does not play an important role in the development and maintenance of sarcopenia in healthy, non-obese, postmenopausal women.
Eat, run, and…shiver? From the exercise – diet and energy balance symposium at CSEP 2005
Authors: Doucet Éric
Published: May 2007

This short introduction includes a brief description of papers that were prepared following the “Symposium on Exercise – Diet and Energy Balance”, which was presented at the Canadian Society for Exercise Physiology annual meeting in the autumn of 2005. Briefly, these three papers discuss findings related to (i) the emerging role of exercise in the treatment of obesity and its co-morbidities, (ii) the role of novel proteins secreted by fat, and (iii) the control of appetite and food intake after successful weight loss.
Epidemiological studies of exercise in diabetes prevention
Authors: Hu Gang , Lakka Timo A. , Kilpeläinen Tuomas O. , Tuomilehto Jaakko
Published: May 2007

Type 2 diabetes is one of the fastest growing public health problems in both developed and developing countries. It is estimated that the number of people with diabetes in the world will double in coming years, from 171 million in 2000 to 366 million in 2030. Cardiovascular disease accounts for more than 70% of total mortality among patients with type 2 diabetes. The associations of physical activity, physical fitness, and changes in the lifestyle with the risk of type 2 diabetes have been assessed by a number of prospective studies and clinical trials in the past decade. Several studies have also evaluated the joint associations of physical activity, body mass index, and glucose levels with the risk of type 2 diabetes. Prospective studies and clinical trials have shown that moderate or high levels of physical activity or physical fitness and changes in the lifestyle (dietary modification and increase in physical activity) can prevent type 2 diabetes. Our review of the scientific evidence confirms that 30 min/d of moderate- or high-level physical activity is an effective and safe way to prevent type 2 diabetes in all populations.
HADRON FORMATION IN HIGH ENERGY ELEMENTARY AND NUCLEAR COLLISIONS
Authors: STOCK REINHARD
Published: May 2007

We consider the dynamical origin of the apparent statistical equilibrium that governs the yields, and yield ratios, of all hadron and resonance species (consisting of the three light quark flavours) produced in nucleus-nucleus collisions from AGS via SPS to RHIC energies [Formula: see text]. This hadro-chemical equilibrium state is well described, overall, by the grand canonical, quasi-classical Gibbs ensemble of all corresponding hadrons and resonances. In order to pin down the stochastic elements, featured by the dynamical evolution prior to hadron formation and hadronic "chemical" (i.e. species) freeze-out, and determining the eventual equilibrium state, we concentrate on the high energy domain, [Formula: see text], where a model of primordial perturbative QCD partonic shower evolution appears plausible. For guidance concerning a hadronization model we revisit the QCD description of jet-induced hadron formation in e+e- annihilation at LEP energy. At the end of the pQCD partonic shower evolution a stage of color neutralization and flavour recombination leads to transition into non perturbative QCD clusters or strings, that decay to hadrons/resonances under phase space dominance. The combination of stochastic shower multiplication and cluster decay to the phase space defined by the hadron/resonancemass and spin spectrum results in a hadronization output featuring statistical equilibrium of the species, which is well described by the canonical Gibbs ensemble. We then assume that hadronization in A + A collisions occurs from a similar stage of singlet cluster formation. However, owing to the extreme overall energy density these clusters should overlap spatially, giving rise to extended super-cluster formation, increasing with [Formula: see text], A and collision centrality. In the limit of an extended volume decaying coherently, hadronization is free of local quantum number conservation constraints. This leads to strangeness enhancement and explains the success of a grand canonical description.
DEFORMATION QUANTIZATION OF CONFINED SYSTEMS
Authors: DIAS NUNO COSTA , PRATA JOÃO NUNO
Published: May 2007

The Weyl–Wigner formulation of quantum confined systems poses several interesting problems. The energy stargenvalue equation as well as the dynamical equation do not display the expected solutions. In this paper, we review some previous results on the subject and add some new contributions. We reformulate the confined energy eigenvalue equation by adding to the Hamiltonian a new (distributional) boundary potential. The new Hamiltonian is proved to be globally defined and self-adjoint. Moreover, it yields the correct Weyl–Wigner formulation of the confined system.
GENERATING AND DISTRIBUTING TWO-PHOTON ENTANGLED SPATIAL QUDITS
Authors: LIMA G. , NEVES LEONARDO , SANTOS IVAN F. , MONKEN C. H. , AGUIRRE GÓMEZ J. G. , SAAVEDRA CARLOS , PÁDUA S.
Published: May 2007

We report an experiment to generate and propagate two entangled spatial qudits, [Formula: see text]-dimensional quantum systems, using spontaneous parametric down-conversion. The manipulation, via pump beam, of the transverse spatial correlation between the photon pairs is explored. Inserting apertures with [Formula: see text]-slits in the arms of the down-converted photons, we associate the qudit space with the [Formula: see text] possible paths followed by each photon. Experimental results for qudits with [Formula: see text] and 8 are shown. We demonstrate that the generated states cannot be classically correlated. We also show the propagation of entangled states of spatial qudits. Their free-space distribution is performed at the laboratory scale and the propagated states maintain a high fidelity with their original form.
THE DIFFUSION OF I-MODE OVERSEAS: A PERSPECTIVE OF INSTITUTIONAL DIFFERENCES
Authors: HUNG CHIA-LIANG , YEH SHU-YU
Published: May 2007

The Japanese telecom giant DoCoMo launched promoted its proprietary i-mode mobile services in 1999 and overseas in 2002. Diffusion overseas was much slower than expected, however. This paper investigates the diffusion of Japanese i-mode mobile internet in Europe from an institutional perspective, focusing on five earlier i-mode overseas operators located in Taiwan, The Netherlands, Germany, Belgium, and France. We found four strategic institutional levers that stimulated i-mode domestic diffusion but failed to appear in overseas areas: operator leadership, subscriber scale, mobile penetration rate, and the ability of the firm to coordinate capability among complements. We propose strategies to internationalize a new standard by co-branding with local vendors and by using penetration pricing as an incentive for switching. Additionally, we recommend an industrial policy that drives cannibalization to facilitate mobile migration to a more advanced standard.
TECHNOLOGICAL INNOVATIONS AND m-COMMERCE APPLICATIONS
Authors: RATTEN VANESSA , RATTEN HAMISH
Published: May 2007

Many technological innovations have occurred within the past decade that have revolutionized the banking industry. The most important has been the Internet and the emergence of mobile-commerce (m-commerce). The aim of this paper is to investigate how Wireless Application Protocol (WAP) banking is being implemented with younger adopters. A conceptual model is developed based on the behavioral intentions younger adopters have on WAP banking that is tested through a survey instrument. Social cognitive theory underpins the conceptual model and helps to explain some of the findings from the study. Suggestions for future research are also espoused.
Different kinases regulate activation of voltage-dependent calcium channels by depolarization in GH3 cells
Authors: Vela Jorge , Pérez-Millán María Inés , Becu-Villalobos Damasia , Díaz-Torga Graciela
Published: May 2007

The L-type Ca2+ channel is the primary voltage-dependent Ca2+-influx pathway in many excitable and secretory cells, and direct phosphorylation by different kinases is one of the mechanisms involved in the regulation of its activity. The aim of this study was to evaluate the participation of Ser/Thr kinases and tyrosine kinases (TKs) in depolarization-induced Ca2+ influx in the endocrine somatomammotrope cell line GH3. Intracellular Ca2+ concentration ([Ca2+]i) was measured using a spectrofluorometric method with fura 2-AM, and 12.5 mM KCl (K+) was used as a depolarization stimulus. K+ induced an abrupt spike (peak) in [Ca2+]i that was abolished in the presence of nifedipine, showing that K+ enhances [Ca2+]i, preferably activating L-type Ca2+ channels. H89, a selective PKA inhibitor, significantly reduced depolarization-induced Ca2+ mobilization in a concentration-related manner when it was applied before or after K+, and okadaic acid, an inhibitor of Ser/Thr phosphatases, which has been shown to regulate PKA-stimulated L-type Ca2+ channels, increased K+-induced Ca2+ entry. When PKC was activated by PMA, the K+-evoked peak in [Ca2+]i, as well as the plateau phase, was significantly reduced, and chelerythrine (a PKC inhibitor) potentiated the K+-induced increase in [Ca2+]i, indicating an inhibitory role of PKC in voltage-dependent Ca2+ channel (VDCC) activity. Genistein, a TK inhibitor, reduced the K+-evoked increase in [Ca2+]i, but, unexpectedly, the tyrosine phosphatase inhibitor orthovanadate reduced not only basal Ca2+ levels but, also, Ca2+ influx during the plateau phase. Both results suggest that different TKs may act differentially on VDCC activation. Activation of receptor TKs with epidermal growth factor (EGF) or vascular endothelial growth factor potentiated K+-induced Ca2+ influx, and AG-1478 (an EGF receptor inhibitor) decreased it. However, inhibition of the non-receptor TK pp60 c-Src enhanced K+-induced Ca2+ influx. The present study strongly demonstrates that a complex equilibrium among different kinases and phosphatases regulates VDCC activity in the pituitary cell line GH3: PKA and receptor TKs, such as vascular endothelial growth factor receptor and EGF receptor, enhance depolarization-induced Ca2+ influx, whereas PKC and c-Src have an inhibitory effect. These kinases modulate membrane depolarization and may therefore participate in the regulation of a plethora of intracellular processes, such as hormone secretion, gene expression, protein synthesis, and cell proliferation, in pituitary cells.
MMPs contribute to TNF-α-induced alteration of the blood-cerebrospinal fluid barrier in vitro
Authors: Zeni Patrick , Doepker Eva , Topphoff Ulf Schulze , Huewel Sabine , Tenenbaum Tobias , Galla Hans-Joachim
Published: May 2007

The epithelial cells of the choroid plexus separate the central nervous system from the blood forming the blood-cerebrospinal fluid (CSF) barrier. The choroid plexus is the main source of CSF, whose composition is markedly changed during pathological disorders, for example regarding matrix metalloproteases (MMPs) and tissue inhibitors of matrix metalloproteases (TIMPs). In the present study, we analyzed the impact of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) on the blood-CSF barrier using an in vitro model based on porcine choroid plexus epithelial cells (PCPEC). TNF-α evoked distinct inflammatory processes as shown by mRNA upregulation of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. The cytokine caused a drastic decrease in transepithelial electrical resistance within several hours representing an enhanced permeability of PCPEC monolayers. In addition, the distribution of tight junction proteins was altered. Moreover, MMP activity in PCPEC supernatants was significantly increased by TNF-α, presumably due to a diminished expression of TIMP-3 that was similarly observed. MMP-2, -3, and -9 as well as TIMP-1 and -2 were also analyzed and found to be differentially regulated by the cytokine. The TNF-α-induced breakdown of the blood-CSF barrier could partially be blocked by the MMP inhibitor GM-6001. Our results show a contribution of MMPs to the inflammatory breakdown of the blood-CSF barrier in vitro. Thus TNF-α may mediate the binding of leukocytes to cellular adhesion molecules and the transmigration across the blood-CSF barrier.
Membrane potential gradient is carbon monoxide-dependent in mouse and human small intestine
Authors: Sha Lei , Farrugia Gianrico , Harmsen W. Scott , Szurszewski Joseph H.
Published: May 2007

The aims of this study were to quantify the change in resting membrane potential (RMP) across the thickness of the circular muscle layer in the mouse and human small intestine and to determine whether the gradient in RMP is dependent on the endogenous production of carbon monoxide (CO). Conventional sharp glass microelectrodes were used to record the RMPs of circular smooth muscle cells at different depths in the human small intestine and in wild-type, HO2-KO, and W/WVmutant mouse small intestine. In the wild-type mouse and human intestine, the RMP of circular smooth muscle cells near the myenteric plexus was −65.3 ± 2 mV and −58.4 ± 2 mV, respectively, and −60.1 ± 2 mV and −49.1 ± 1 mV, respectively, in circular smooth muscle cells at the submucosal border. Oxyhemoglobin (20 μM), a trapping agent for CO, and chromium mesoporphyrin IX, an inhibitor of heme oxygenase, abolished the transwall gradient. The RMP gradients in mouse and human small intestine were not altered by NG-nitro-l-arginine (200 μM). No transwall RMP gradient was found in HO2-KO mice and W/WVmutant mice. TTX (1 μM) and 1H-[1,2,4-]oxadiazolo[4,3-a]quinoxalin-1-one (10 μM) had no effect on the RMP gradient. These data suggest that the gradient in RMP across the thickness of the circular muscle layer of mouse and human small intestine is CO dependent.
PECAM-1 (CD 31) mediates transendothelial leukocyte migration in experimental colitis
Authors: Rijcken Emile , Mennigen Rudolf B. , Schaefer Sebastian D. , Laukoetter Mike G. , Anthoni Christoph , Spiegel Hans-Ullrich , Bruewer Matthias , Senninger Norbert , Krieglstein Christian F.
Published: May 2007

Transendothelial migration of circulating leukocytes into the colonic wall is a key step in the development of the inflammatory infiltrate in inflammatory bowel disease (IBD). The platelet-endothelial cell adhesion molecule-1 PECAM-1 (CD31) is expressed in the tight junction area of endothelial cells, where it is supposed to support the transmigration process. The aim of this study was to determine the role of PECAM-1 in experimental IBD and to show whether blockade of PECAM-1 has therapeutic effects. Chronic colitis was induced in female BALB/c mice by cyclic oral administration of dextran sodium sulfate (DSS) 3% (wt/vol). Expression of PECAM-1 was visualized by immunohistochemistry. In the treatment group animals received 1 mg/kg anti-PECAM-1 (2H8) ip daily starting on day 26. On day 30 leukocyte adhesion and migration was measured during N2O-isoflurane anesthesia in the distal colon by intravital microscopy. Disease activity index (DAI), histology, and MPO levels were compared with healthy and diseased controls. PECAM-1 was expressed in colitic mice. Chronic DSS colitis was characterized by a marked increase in rolling, adherent, and transmigrated leukocytes compared with healthy controls. Immunoblockade of PECAM-1 reduced leukocyte transmigration significantly and also diminished leukocyte rolling and sticking in an indirect manner. It also resulted in a significantly diminished DAI and MPO levels, as well as an amelioration of the histological inflammation score. PECAM-1 plays an important role in transendothelial leukocyte migration in DSS colitis. PECAM-1 could be a novel target for antibody-based treatment in IBD.
Inspiratory resistance delays the reporting of symptoms with central hypovolemia: association with cerebral blood flow
Authors: Rickards Caroline A. , Ryan Kathy L. , Cooke William H. , Lurie Keith G. , Convertino Victor A.
Published: May 2007

We tested the hypothesis that breathing through an inspiratory threshold device (ITD) during progressive central hypovolemia would protect cerebral perfusion and attenuate the reporting of presyncopal symptoms. Eight human subjects were exposed to lower-body negative pressure (LBNP) until the presence of symptoms while breathing through either an active ITD (−7 cmH2O impedance) or a sham ITD (0 cmH2O). Cerebral blood flow velocity (CBFV) was measured continuously via transcranial Doppler and analyzed in both time and frequency domains. Subjects were asked to report any subjective presyncopal symptoms (e.g., dizziness, nausea) at the conclusion of each LBNP exposure. Symptoms were coincident with physiological evidence of cardiovascular collapse (e.g., hypotension, bradycardia). Breathing on the active ITD increased LBNP tolerance time (mean ± SE) from 2,014 ± 106 s to 2,259 ± 138 s ( P = 0.006). We compared CBFV responses at the time of symptoms during the sham ITD trial with those at the same absolute time during the active ITD trial (when there were no symptoms). While there was no difference in mean CBFV at these time points (sham, 44 ± 4 cm/s vs. active, 47 ± 4; P = 0.587), total oscillations (sum of high- and low-frequency spectral power) of CBFV were higher ( P = 0.004) with the active ITD (45.6 ± 10.2 cm/s2) than the sham ITD (22.1 ± 5.4 cm/s2). We conclude that greater oscillations around the same absolute level of mean CBFV are induced by inspiratory resistance and may contribute to the delay in symptoms and cardiovascular collapse that accompany progressive central hypovolemia.
Vasopressin-induced nitric oxide production in rat inner medullary collecting duct is dependent on V2receptor activation of the phosphoinositide pathway
Authors: O'Connor Paul M. , Cowley Allen W.
Published: May 2007

We previously reported that arginine vasopressin (AVP) stimulates the production of nitric oxide (NO) in inner medullary collecting duct (IMCD) via activation of V2 receptors (V2R) and the mobilization of intracellular Ca2+. The aim of this study was to determine the pathway(s) through which this response is mediated. IMCDs were dissected from male Sprague-Dawley rats and intracellular Ca2+concentration ([Ca2+]i) and NO production were measured using a fluorescence imaging system. AVP (100 nmol/l) produced a rapid increase [Ca2+]iof 381 ± 78 nmol/l that was followed by a significant increase of NO production (166 ± 61%). The specific nonpeptide V2R antagonist OPC31260 (1 μM), but not the V1R antagonist OPC21268 (1 μM), inhibited the increase in [Ca2+]i(up to 91 ± 5%) and abolished the NO response to AVP. Both the phospholipase C inhibitor U73112 (3 μM) and the inositol ( 1 , 4 , 5 ) tri-phosphate 3 receptor blocker 2-APB (75 μM) reduced the peak [Ca2+]iresponse to AVP (by 65 ± 9 and 59 ± 15%, respectively) and abolished the NO response. Although forskolin (100 μM; an activator of adenylyl cyclase) elicited a moderate increase in [Ca2+]i, neither preincubation with the adenylyl cyclase inhibitor 2′-5′-dideoxyadenosine (50 μM) nor the protein kinase A (PKA) inhibitor PKA14-22(100 μM) significantly inhibited peak [Ca2+]iin response to AVP. IMCD [Ca2+]iresponses to AVP were reduced by 72 ± 8% when incubated in Ca2+-free media and could be completely abolished by preincubation with the Ca2+-ATPase inhibitor thapsigargin. We conclude that AVP-induced NO production in IMCD is dependent on V2R activation of the phosphoinositide pathway and the mobilization of Ca2+from both intracellular and extracellular pools.
Role of endogenous CYP450 metabolites of arachidonic acid in maintaining the glomerular protein permeability barrier
Authors: Williams Jan Michael , Sharma Mukut , Anjaiahh Siddam , Falck John R. , Roman Richard J.
Published: May 2007

This study examined the metabolism of arachidonic acid (AA) by cytochrome P-450 enzymes in isolated glomeruli and the effects of selective inhibitors of the synthesis of 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatetraenoic acids (EETs) on glomerular permeability to albumin ( Palb). Glomeruli avidly produced 20-HETE, EETs, dihydroxyeicosatetraenoic acids (diHETEs), and HETEs when incubated with exogenous AA. N-hydroxy- N′-(4-butyl-2-methylphenyl)formamidine (HET0016; 10 μM) selectively inhibited the formation of 20-HETE by 95% and increased Palbfrom 0.00 ± 0.08 to 0.73 ± 0.10 ( n = 43 glomeruli, 4 rats). Addition of a 20-HETE mimetic, 20-hydroxyeicosa-5( Z),14( Z)-dienoic acid (20-5,14-HEDE; 1 μM) opposed the effects of HET0016 (10 μM) to increase Palb(0.21 ± 0.10, n = 36 glomeruli, 4 rats). Preincubation of glomeruli with exogenous AA to increase basal production of 20-HETE had a similar effect. We also examined the effect of an epoxygenase inhibitor, N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide (MSPPOH; 5 μM), on Palb. MSPPOH (5 μM) significantly increased Palbbut had no effect on the synthesis of EETs in glomeruli incubated with AA. However, MSPPOH (5 μM) selectively reduced epoxygenase activity by 50% in glomeruli incubated without added AA. Pretreatment with 8,9-EET (100 nM) attenuated the effects of MSPPOH (5 μM) on Palb. These results indicate that glomeruli produce 20-HETE, EETs, diHETEs, and HETEs and that endogenously formed 20-HETE and EETs play an essential role in the maintenance of the glomerular permeability barrier to albumin.
Recovery from acute renal failure predisposes hypertension and secondary renal disease in response to elevated sodium
Authors: Spurgeon-Pechman Kimberly R. , Donohoe Deborah L. , Mattson David L. , Lund Hayley , James Leilani , Basile David P.
Published: May 2007

Recovery of renal function is a well-characterized feature of models of acute renal failure; however, more recent studies have reported a predisposition to chronic renal disease. This study sought to determine the susceptibility to sodium-dependent hypertension following recovery from ischemic acute renal failure. Following ischemia-reperfusion (I/R) injury, rats were allowed to recover for 35 days on a 0.4% salt diet, then were switched to 4.0% salt diet for an additional 28 days. Blood pressure was significantly increased in postischemic rats switched to high-sodium diet at day 35 (19 ± 9 mmHg) compared with postischemic rats maintained on low-sodium diet. Plasma renin activity and creatinine clearance were not affected by I/R injury. The ischemic injury combined with transfer to 4.0% salt diet resulted in marked renal hypertrophy characterized by interstitial cellular deposition, tubular dilation, and enhanced rates of albumin excretion. Glomerular structure was altered in post-I/R rats switched to high-sodium diet but not in those maintained on low-sodium diets. When rats were acclimated to high-sodium diet before I/R injury, the early injury was similar to that observed in animals acclimated to low-sodium diet, and these animals progressed rapidly toward chronic kidney disease, as evidenced by advancement of albuminuria. These data suggest that the recovery from acute I/R injury is not complete, compromises Na homeostasis, and predisposes hypertension and secondary renal disease.
Arsenic trioxide inhibits growth of As4.1 juxtaglomerular cells via cell cycle arrest and caspase-independent apoptosis
Authors: Han Yong Hwan , Kim Sung Zoo , Kim Suhn Hee , Park Woo Hyun
Published: May 2007

We investigated the in vitro effects of arsenic trioxide on cell growth, cell cycle regulation, and apoptosis in As4.1 juxtaglomerular cells. Arsenic trioxide inhibited the growth of As4.1 cells with an IC50of ∼5 μM. Arsenic trioxide induced S phase arrest of the cell cycle and very efficiently stimulated apoptosis in As4.1 cells, as evidenced by flow cytometric detection of sub-G1DNA content, annexin V binding assay, and 4′-6-diamidino-2-phenylindole staining. This apoptotic process was accompanied by the loss of mitochondrial transmembrane potential (ΔΨm), a decrease in Bcl-2, the activation of caspase-3, and cleavage of poly(ADP-ribose) polymerase. However, all of the caspase inhibitors tested in this experiment failed to rescue As4.1 cells from arsenic trioxide-induced cell death in view of sub-G1cells and annexin V positive-staining cells. However, a caspase-8 inhibitor (Z-IETD-FMK) noticeably decreased the loss of ΔΨmin arsenic trioxide-treated cells. When we examined the changes in reactive oxygen species (ROS), H2O2, or O2•−in arsenic trioxide-treated cells, H2O2was significantly decreased and O2•−was increased. In addition, we detected a decreased GSH content in arsenic trioxide-treated cells. Taken together, we have demonstrated that arsenic trioxide as a ROS generator potently inhibited the growth of As4.1 JG cells through S phase arrest of the cell cycle and caspase-independent apoptosis.
Lidocaine Promotes the Trafficking and Functional Expression of Nav1.8 Sodium Channels in Mammalian Cells
Authors: Zhao Juan , Ziane Rahima , Chatelier Aurélien , O'Leary Michael E. , Chahine Mohamed
Published: May 2007

Nociceptive neurons of the dorsal root ganglion (DRG) express a combination of rapidly gating TTX-sensitive and slowly gating TTX-resistant Na currents, and the channels that produce these currents have been cloned. The Nav1.7 and Nav1.8 channels encode for the rapidly inactivating TTX-sensitive and slowly inactivating TTX-resistant Na currents, respectively. Although the Nav1.7 channel expresses well in cultured mammalian cell lines, attempts to express the Nav1.8 channel using similar approaches has been met with limited success. The inability to heterologously express Nav1.8 has hampered detailed characterization of the biophysical properties and pharmacology of these channels. In this study, we investigated the determinants of Nav1.8 expression in tsA201 cells, a transformed variant of HEK293 cells, using a combination of biochemistry, immunochemistry, and electrophysiology. Our data indicate that the unusually low expression levels of Nav1.8 in tsA201 cells results from a trafficking defect that traps the channel protein in the endoplasmic reticulum. Incubating the cultured cells with the local anesthetic lidocaine dramatically enhanced the cell surface expression of functional Nav1.8 channels. The biophysical properties of the heterologously expressed Nav1.8 channel are similar but not identical to those of the TTX-resistant Na current of native DRG neurons, recorded under similar conditions. Our data indicate that the lidocaine acts as a molecular chaperone that promotes efficient trafficking and increased cell surface expression of Nav1.8 channels.
Sensory Prediction Errors Drive Cerebellum-Dependent Adaptation of Reaching
Authors: Tseng Ya-weng , Diedrichsen Jörn , Krakauer John W. , Shadmehr Reza , Bastian Amy J.
Published: May 2007

The cerebellum is an essential part of the neural network involved in adapting goal-directed arm movements. This adaptation might rely on two distinct signals: a sensory prediction error or a motor correction. Sensory prediction errors occur when an initial motor command is generated but the predicted sensory consequences do not match the observed values. In some tasks, these sensory errors are monitored and result in on-line corrective motor output as the movement progresses. Here we asked whether cerebellum-dependent adaptation of reaching relies on sensory or on-line motor corrections. Healthy controls and people with hereditary cerebellar ataxia reached during a visuomotor perturbation in two conditions: “shooting” movements without on-line corrections and “pointing” movements that allowed for on-line corrections. Sensory (i.e., visual) errors were available in both conditions. Results showed that the addition of motor corrections did not influence adaptation in control subjects, suggesting that only sensory errors were needed for learning. Cerebellar subjects were comparably impaired in both adaptation conditions relative to controls, despite abnormal and inconsistent on-line motor correction. Specifically, poor on-line motor corrections were unrelated to cerebellar subjects' adaptation deficit (i.e., adaptation did not worsen), further suggesting that only sensory prediction errors influence this process. Therefore adaptation to visuomotor perturbations depends on the cerebellum and is driven by the mismatch between predicted and actual sensory outcome of motor commands.
Periaqueductal Gray Metabotropic Glutamate Receptor Subtype 7 and 8 Mediate Opposite Effects on Amino Acid Release, Rostral Ventromedial Medulla Cell Activities, and Thermal Nociception
Authors: Marabese Ida , Rossi Francesca , Palazzo Enza , de Novellis Vito , Starowicz Katarzyna , Cristino Luigia , Vita Daniela , Gatta Luisa , Guida Francesca , Di Marzo Vincenzo , Rossi Francesco , Maione Sabatino
Published: May 2007

The current study has investigated the involvement of periaqueductal gray (PAG) metabotropic glutamate subtype 7 and 8 receptors (mGluR7and mGluR8) in modulating rostral ventromedial medulla (RVM) ongoing and tail flick–related on and off cell activities. Our study has also investigated the role of PAG mGluR7on thermoceptive threshold and PAG glutamate and GABA release. Intra-ventrolateral PAG ( S)-3,4-dicarboxyphenylglycine [( S)-3,4-DCPG (2 and 4 nmol/rat)] or N,NI-dibenzhydrylethane-1,2-diamin dihydrochloride (AMN082, (1 and 2 nmol/rat), selective mGluR8and mGluR7agonists, respectively, caused opposite effects on the ongoing RVM on and off cell activities. Tail flick latency was increased or decreased by ( S)-3,4-DCPG or AMN082 (2 nmol/rat), respectively. ( S)-3,4-DCPG reduced the pause and delayed the onset of the off cell pause. Conversely, AMN082 increased the pause and shortened the onset of off cell pause. ( S)-3,4-DCPG or AMN082 did not change the tail flick-induced onset of on-cell peak firing. The tail flick latency and its related electrophysiological effects induced by ( S)-3,4-DCPG or AMN082 were prevented by (RS)-α-methylserine-o-phosphate (100 nmol/rat), a group III mGluR antagonist. Intra-ventrolateral PAG perfusion with AMN082 (10 and 25 μM), decreased thermoceptive thresholds and glutamate extracellular levels. A decrease in GABA release was also observed. These results show that stimulation of PAG mGluR8or mGluR7could either relieve or worsen pain perception. The opposite effects on pain behavior correlate with the opposite roles played by mGluR7and mGluR8on glutamate and GABA release and the ongoing and tail flick-related activities of the RVM on and off cells.
Membrane Properties and Firing Patterns of Inferior Colliculus Neurons: An In Vivo Patch-Clamp Study in Rodents
Authors: Tan M. L. , Theeuwes H. P. , Feenstra L. , Borst J.G.G.
Published: May 2007

The inferior colliculus (IC) is a large auditory nucleus in the midbrain, which is a nearly obligatory relay center for ascending auditory projections. We made in vivo whole cell patch-clamp recordings of IC cells in young-adult anesthetized C57/Bl6 mice and Wistar rats to characterize their membrane properties and spontaneous inputs. We observed spikelets in both rat (18%) and mouse (13%) IC neurons, suggesting that IC neurons may be connected by electrical synapses. In many cells, spontaneous postsynaptic potentials were sufficiently large to contribute to spike irregularity. Cells differed considerably in the number of simultaneous spontaneous postsynaptic potentials that would be needed to trigger an action potential. Depolarizing and hyperpolarizing current injections showed six different types of firing patterns: buildup, accelerating, burst-onset, burst-sustained, sustained, and accommodating. Their relative frequencies were similar in both species. In mice, about half of the cells showed a clear depolarizing sag, suggesting that they have the hyperpolarization-activated current Ih. This sag was observed more often in burst and in accommodating cells than in buildup, accelerating, or sustained neurons. Cells with Ih had a significantly more depolarized resting membrane potential. They were more likely to fire rebound spikes and generally showed long-lasting afterhyperpolarizations following long depolarizations. We therefore suggest a separate functional role for Ih.
Tumor Angiogenesis Promoted by Ex vivo Differentiated Endothelial Progenitor Cells Is Effectively Inhibited by an Angiogenesis Inhibitor, TK1-2
Authors: Oh Ho-Kyun , Ha Jung-Min , O Eunju , Lee Byung Hun , Lee Suk Keun , Shim Byoung-Shik , Hong Yong-Kil , Joe Young Ae
Published: May 2007

Neovascularization plays a critical role in the growth and metastatic spread of tumors and involves recruitment of circulating endothelial progenitor cells (EPC) from bone marrow as well as sprouting of preexisting endothelial cells. In this study, we examined if EPCs could promote tumor angiogenesis and would be an effective cellular target for an angiogenesis inhibitor, the recombinant kringle domain of tissue-type plasminogen activator (TK1-2). When TK1-2 was applied in the ex vivo culture of EPCs isolated from human cord blood, TK1-2 inhibited adhesive differentiation of mononuclear EPCs into endothelial-like cells. In addition, it inhibited the migration of ex vivo cultivated EPCs and also inhibited their adhesion to fibronectin matrix or endothelial cell monolayer. When A549 cancer cells were coimplanted along with ex vivo cultivated EPCs s.c. in nude mice, the tumor growth was increased. However, the tumor growth and the vascular density of tumor tissues increased by coimplanted EPCs were decreased upon TK1-2 treatment. Accordingly, TK1-2 treatment reduced the remaining number of EPCs in tumor tissues and their incorporation into the host vascular channels. In addition, overall expression levels of vascular endothelial growth factor (VEGF) and von Willebrand factor in tumor tissues were decreased upon TK1-2 treatment. Interestingly, strong VEGF expression by implanted EPCs was decreased by TK1-2. Finally, we confirmed in vitro that TK1-2 inhibited VEGF secretion of EPCs. TK1-2 also inhibited endothelial cell proliferation and migration induced by the conditioned medium of EPCs. Therefore, we concluded that EPCs, as well as mature endothelial cells, could be an important target of TK1-2. [Cancer Res 2007;67(10):4851–9]
Copper-Transporting P-Type ATPase, ATP7A, Confers Multidrug Resistance and Its Expression Is Related to Resistance to SN-38 in Clinical Colon Cancer
Authors: Owatari Satsuki , Akune Satoshi , Komatsu Masaharu , Ikeda Ryuji , Firth Stephen D. , Che Xiao-Fang , Yamamoto Masatatsu , Tsujikawa Kazutake , Kitazono Masaki , Ishizawa Takashi , Takeuchi Toru , Aikou Takashi , Mercer Julian F.B. , Akiyama Shin-ichi , Furukawa Tatsuhiko
Published: May 2007

We and others have shown that the copper transporters ATP7A and ATP7B play a role in cellular resistance to cis-diaminedichloroplatinum (II) (CDDP). In this study, we found that ATP7A transfection of Chinese hamster ovary cells (CHO-K1) and fibroblasts isolated from Menkes disease patients enhanced resistance not only to CDDP but also to various anticancer drugs, such as vincristine, paclitaxel, 7-ethyl-10-hydroxy-camptothecin (SN-38), etoposide, doxorubicin, mitoxantron, and 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin (CPT-11). ATP7A preferentially localized doxorubicin fluorescence to the Golgi apparatus in contrast to the more intense nuclear staining of doxorubicin in the parental cells. Brefeldin A partially and monensin completely altered the distribution of doxorubicin to the nuclei in the ATP7A-expressing cells. ATP7A expression also enhanced the efflux rates of doxorubicin and SN-38 from cells and increased the uptake of SN-38 in membrane vesicles. These findings strongly suggested that ATP7A confers multidrug resistance to the cells by compartmentalizing drugs in the Golgi apparatus and by enhancing efflux of these drugs, and the trans-Golgi network has an important role of ATP7A-related drug resistance. ATP7A was expressed in 8 of 34 (23.5%) clinical colon cancer specimens but not in the adjacent normal epithelium. Using the histoculture drug response assay that is useful for the prediction of drug sensitivity of clinical cancers, ATP7A-expressing colon cancer cells were significantly more resistant to SN-38 than ATP7A-negative cells. Thus, ATP7A confers resistance to various anticancer agents on cancer cells and might be a good index of drug resistance in clinical colon cancers. [Cancer Res 2007;67(10):4860–7]
HMGA1 Controls Transcription of Insulin Receptor to Regulate Cyclin D1 Translation in Pancreatic Cancer Cells
Authors: Kolb Sebastian , Fritsch Ralph , Saur Dieter , Reichert Maximilian , Schmid Roland M. , Schneider Günter
Published: May 2007

The HMGA1 proteins act as architectural transcription factors and are involved in the regulation of genes important in the process of carcinogenesis. Although HMGA1 proteins are overexpressed in most types of cancer, signaling circuits regulated by HMGA1 are not clarified in detail. In this study, we show that HMGA1 proteins promote proliferation of pancreatic cancer cells by accelerating G1 phase progression. Transfection of HMGA1-specific small interfering RNA (siRNA) activates the RB-dependent G1-phase checkpoint due to the impaired expression of cyclin D1. Down-regulation of cyclin D1 after the HMGA1 knockdown is due to translational control and involves the repressor of the eukaryotic translation initiation factor 4E (eIF4E) 4E-BP1. We show that 4E-BP1 and cyclin D1 act downstream of the insulin receptor (IR) in pancreatic cancer cells. At the molecular level transcription of the IR is controlled by a CAAT/enhancer binding protein β (C/EBPβ)/HMGA1 complex. Together, this work defines a novel pathway regulated by HMGA1, which contributes to the proliferation of pancreatic cancer cells. [Cancer Res 2007;67(10):1–8]
Intraprostatic Androgens and Androgen-Regulated Gene Expression Persist after Testosterone Suppression: Therapeutic Implications for Castration-Resistant Prostate Cancer
Authors: Mostaghel Elahe A. , Page Stephanie T. , Lin Daniel W. , Fazli Ladan , Coleman Ilsa M. , True Lawrence D. , Knudsen Beatrice , Hess David L. , Nelson Colleen C. , Matsumoto Alvin M. , Bremner William J. , Gleave Martin E. , Nelson Peter S.
Published: May 2007

Androgen deprivation therapy (ADT) remains the primary treatment for advanced prostate cancer. The efficacy of ADT has not been rigorously evaluated by demonstrating suppression of prostatic androgen activity at the target tissue and molecular level. We determined the efficacy and consistency of medical castration in suppressing prostatic androgen levels and androgen-regulated gene expression. Androgen levels and androgen-regulated gene expression (by microarray profiling, quantitative reverse transcription-PCR, and immunohistochemistry) were measured in prostate samples from a clinical trial of short-term castration (1 month) using the gonadotropin-releasing hormone antagonist, Acyline, versus placebo in healthy men. To assess the effects of long-term ADT, gene expression measurements were evaluated at baseline and after 3, 6, and 9 months of neoadjuvant ADT in prostatectomy samples from men with localized prostate cancer. Medical castration reduced tissue androgens by 75% and reduced the expression of several androgen-regulated genes (NDRG1, FKBP5, and TMPRSS2). However, many androgen-responsive genes, including the androgen receptor (AR) and prostate-specific antigen (PSA), were not suppressed after short-term castration or after 9 months of neoadjuvant ADT. Significant heterogeneity in PSA and AR protein expression was observed in prostate cancer samples at each time point of ADT. Medical castration based on serum testosterone levels cannot be equated with androgen ablation in the prostate microenvironment. Standard androgen deprivation does not consistently suppress androgen-dependent gene expression. Suboptimal suppression of tumoral androgen activity may lead to adaptive cellular changes allowing prostate cancer cell survival in a low androgen environment. Optimal clinical efficacy will require testing of novel approaches targeting complete suppression of systemic and intracrine contributions to the prostatic androgen microenvironment. [Cancer Res 2007;67(10):5033–41]