bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary fructose causes tubulointerstitial injury in the normal rat kidney
Authors: Nakayama Takahiro , Kosugi Tomoki , Gersch Michael , Connor Thomas , Sanchez-Lozada Laura Gabriela , Lanaspa Miguel A. , Roncal Carlos , Perez-Pozo Santos E. , Johnson Richard J. , Nakagawa Takahiko
Published: January 2010

Recent studies suggest that the metabolic syndrome is associated with renal disease. We previously reported that a high-fructose diet, but not a high-glucose diet, can induce metabolic syndrome and accelerate chronic renal disease in rats. We now examined the effects of a high-fructose diet on normal rat kidneys. Three groups of Sprague-Dawley rats were pair fed a special diet containing 60% fructose, 60% glucose, or control standard rat chow for 6 wk, and then histological studies were performed. The effect of fructose to induce cell proliferation in cultured proximal tubular cells was also performed. Fructose diet, but not glucose diet, significantly increased kidney weight by 6 wk. The primary finding was tubular hyperplasia and proliferation involving all segments of the proximal tubules while glomerular changes were not observed. This is the same site where the fructose transporters (GLUT2 and -5) as well as the key enzyme in fructose metabolism (ketohexokinase) were expressed. Consistently, fructose also induced proliferation of rat proximal tubular cells in culture. In vivo, tubular proliferation was also associated with focal tubular injury, with type III collagen deposition in the interstitium, an increase in α-smooth muscle actin positive myofibroblasts, and an increase in macrophage infiltration. In conclusion, a high-fructose diet induces cell proliferation and hyperplasia in proximal tubules, perhaps via a direct metabolic effect. The effect is independent of total energy intake and is associated with focal tubulointerstitial injury. These studies may provide a mechanism by which metabolic syndrome causes renal disease.
Phosphorylation of UT-A1 on serine 486 correlates with membrane accumulation and urea transport activity in both rat IMCDs and cultured cells
Authors: Klein Janet D. , Blount Mitsi A. , Fröhlich Otto , Denson Chad E. , Tan Xiaoxiao , Sim Jae H. , Martin Christopher F. , Sands Jeff M.
Published: January 2010

Vasopressin is the primary hormone regulating urine-concentrating ability. Vasopressin phosphorylates the UT-A1 urea transporter in rat inner medullary collecting ducts (IMCDs). To assess the effect of UT-A1 phosphorylation at S486, we developed a phospho-specific antibody to S486-UT-A1 using an 11 amino acid peptide antigen starting from amino acid 482 that bracketed S486 in roughly the center of the sequence. We also developed two stably transfected mIMCD3 cell lines: one expressing wild-type UT-A1 and one expressing a mutated form of UT-A1, S486A/S499A, that is unresponsive to protein kinase A. Forskolin stimulates urea flux in the wild-type UT-A1-mIMCD3 cells but not in the S486A/S499A-UT-A1-mIMCD3 cells. The phospho-S486-UT-A1 antibody identified UT-A1 protein in the wild-type UT-A1-mIMCD3 cells but not in the S486A/S499A-UT-A1-mIMCD3 cells. In rat IMCDs, forskolin increased the abundance of phospho-S486-UT-A1 (measured using the phospho-S486 antibody) and of total UT-A1 phosphorylation (measured by 32P incorporation). Forskolin also increased the plasma membrane accumulation of phospho-S486-UT-A1 in rat IMCD suspensions, as measured by biotinylation. In rats treated with vasopressin in vivo, the majority of the phospho-S486-UT-A1 appears in the apical plasma membrane. In summary, we developed stably transfected mIMCD3 cell lines expressing UT-A1 and an S486-UT-A1 phospho-specific antibody. We confirmed that vasopressin increases UT-A1 accumulation in the apical plasma membrane and showed that vasopressin phosphorylates UT-A1 at S486 in rat IMCDs and that the S486-phospho-UT-A1 form is primarily detected in the apical plasma membrane.
Early Postnatal Loss of Heat Sensitivity Among Cutaneous Myelinated Nociceptors in Swiss–Webster Mice
Authors: Ye Yi , Woodbury C. Jeffery
Published: January 2010

Cutaneous myelinated nociceptors are known to exhibit considerable heterogeneity in their response to noxious heat. In the present experiments, we studied heat sensitivity among myelinated nociceptors during early postnatal life to determine whether this heterogeneity is correlated with other physiological and anatomical properties. A total of 129 cutaneous myelinated nociceptors were recorded intracellularly and characterized using mechanical and thermal skin stimuli in ex vivo preparations from neonatal Swiss–Webster (SW) mice across postnatal ages P2–P10; physiologically identified cells were iontophoretically labeled with neurobiotin for analyses of dorsal horn terminations from heat-sensitive and heat-insensitive cells. Our results show that heat sensitivity is not strictly correlated with other physiological or anatomical properties, most notably mechanical threshold or laminar termination patterns, of myelinated nociceptors at these ages. Further, we found a marked decline in the number of heat-sensitive myelinated mechanonociceptors (A-mechanoheat nociceptors [AMHs]) during this early postnatal period. Indeed, 68% of myelinated nociceptors were AMHs between P2 and P5, whereas this percentage dropped to 36% between P6 and P10. Multiple independent lines of evidence suggest that this decrease reflects a change in phenotype in a subset of myelinated nociceptors that lose sensitivity to noxious heat in early postnatal life. Interestingly, evidence was also obtained for a significant strain difference since the early transient excess in the number of AMHs in P2–P5 SW neonates was not present in similarly aged neonates from the C57Bl/6 strain. Potential mechanisms underlying these postnatal changes in AMH number are discussed.
Identifying Representative Synergy Matrices for Describing Muscular Activation Patterns During Multidirectional Reaching in the Horizontal Plane
Authors: Muceli Silvia , Boye Andreas Trøllund , d'Avella Andrea , Farina Dario
Published: January 2010

Muscle synergies have been proposed as a simplifying principle of generation of movements based on a low-dimensional control by the CNS. This principle may be useful for movement restoration by, e.g., functional electrical stimulation (FES), if a limited set of synergies can describe several functional tasks. This study investigates the possibility of describing a multijoint reaching task of the upper limb by a linear combination of one set of muscle synergies common to multiple directions. Surface electromyographic (EMG) signals were recorded from 12 muscles of the dominant upper limb of eight healthy men during single-joint movements and a multijoint reaching task in 12 directions in the horizontal plane. The movement kinematics was recorded by a motion analysis system. Muscle synergies were extracted with nonnegative matrix factorization of the EMG envelopes. Synergies were computed either from the single-joint movements to describe the two degrees of freedom independently or from the multijoint movements. On average, the multijoint reaching task could be accurately described in all the directions (coefficient of determination >0.85) by a linear combination of either four synergies extracted from the individual degrees of freedom or three synergies extracted from multijoint movements in at least three reaching directions. These results indicate that a large set of multijoint movements can be generated by a synergy matrix of limited dimensionality and common to all directions if the synergies are extracted from a representative number of directions. The linear combination of synergies may thus be used in strategies for restoring functions, such as FES.
Neural Correlates of Sequence Encoding in Visuomotor Learning
Authors: Agam Yigal , Huang Jie , Sekuler Robert
Published: January 2010

To examine the neural basis of sequence learning, a fundamental but poorly understood human ability, we recorded event-related potentials (ERPs) while subjects viewed and memorized randomly directed sequences of motions for later imitation. Previously, we found that the amplitude of ERPs elicited by successive motion segments decreased as a function of each segment's serial position. This happened when subjects were required to remember the sequence, but not when they were performing a perceptual task. Here, to study the functional significance of this amplitude gradient in sequence learning, we presented each sequence several times in succession and examined changes in ERP amplitude as subjects learned the sequence through repeated observation and imitation. Behaviorally, with each repetition subjects grew more accurate in reproducing what they had seen. At the same time, ERPs grew smaller with each successive presentation, replicating and extending previous demonstrations of repetition suppression. Importantly, a comparison of ERPs to segments occupying different serial positions within a sequence revealed a decreasing amplitude gradient that grew steeper with sequence repetition. This sharpening of the amplitude gradient may reflect an explicit encoding process that relies on a magnitude code for serial order.
Astrocytic iNOS-Dependent Enhancement of Synaptic Release in Mouse Neocortex
Authors: Buskila Yossi , Amitai Yael
Published: January 2010

Nitric oxide (NO) has been recognized as an atypical neuronal messenger affecting synaptic transmission, but its cellular source has remained unresolved as the neuronal NO synthase isoform (nNOS) in brain areas such as the neocortex is expressed only by a small subset of inhibitory neurons. The involvement of the glial NOS isoform (iNOS) in modulating neuronal activity has been largely ignored because it has been accepted that this enzyme is regulated by gene induction following detrimental stimuli. Using acute brain slices from mouse neocortex and electrophysiology, we found that selective inhibition of iNOS reduced both spontaneous and evoked synaptic release. Moreover, iNOS inhibition partially prevented and reversed the potentiation of excitatory synapses in layer 2/3 pyramidal neurons. NOS enzymatic assay confirmed a small but reliable Ca2+-independent activity fraction, consistent with the existence of functioning iNOS in the tissue. Together these data point to astrocytes as a source for the nitrosative regulation of synaptic release in the neocortex.
Limitations on Coupling of Bimanual Movements Caused by Arm Dominance: When the Muscle Homology Principle Fails
Authors: Dounskaia Natalia , Nogueira Keith G. , Swinnen Stephan P. , Drummond Elizabeth
Published: January 2010

Studies of bimanual movements typically report interference between motions of the two arms and preference to perform mirror-symmetrical patterns. However, recent studies have demonstrated that the two arms differ in the ability to control interaction torque (INT). This predicts limitations in the capability to perform mirror-symmetrical movements. Here, two experiments were performed to test this prediction. The first experiment included bimanual symmetrical and asymmetrical circle drawing at two frequency levels. Unimanual circle drawing was also recorded. The increases in cycling frequency caused differences between the two arms in movement trajectories in both bimanual modes, although the differences were more pronounced in the asymmetrical compared with the symmetrical mode. Based on torque analysis, the differences were attributed to the nondominant arm's decreased capability to control INT. The intraarm differences during the symmetrical pattern of bimanual movements were similar (although more pronounced) to those during unimanual movements. This finding was verified in the second experiment for symmetrical bimanual oval drawing. Four oval orientations were used to provide variations in INT. Similar to the first experiment, increases in cycling frequency caused spontaneous deviations from perfect bimanual symmetry associated with inefficient INT control in the nondominant arm. This finding supports the limitations in performing mirror-symmetrical bimanual movements due to differences in joint control between the arms. Based on our results and previous research, we argue that bimanual interference occurs during specification of characteristics of required motion, whereas lower-level generation of muscle forces is independent between the arms. A hierarchical model of bimanual control is proposed.
Synaptic Activation of T-Type Ca2+Channels Via mGluR Activation in the Primary Dendrite of Mitral Cells
Authors: Johnston Jamie , Delaney Kerry R.
Published: January 2010

Mitral cells are the primary output of the olfactory bulb, projecting to many higher brain areas. Understanding how mitral cells process and transmit information is key to understanding olfactory perception. Mitral dendrites possess high densities of voltage-gated channels, are able to initiate and propagate orthodromic and antidromic action potentials, and release neurotransmitter. We show that mitral cells also possess a low-voltage-activated T-type Ca2+current. Immunohistochemistry shows strong Cav3.3 labeling in the primary dendrite and apical tuft with weaker staining in basal dendrites and no staining in somata. A low-voltage-activated Ca2+current activates from −68 mV, is blocked by 500 μM Ni2+and 50 μM NNC 55-0396, but is insensitive to 50 μM Ni2+and 500 μM isradipine. 2-photon Ca2+imaging shows that T channels are functionally expressed in the primary dendrite where their activity determines the resting [Ca2+] and are responsible for subthreshold voltage-dependent Ca2+changes previously observed in vivo. Application of the group 1 mGluR agonist dihydroxyphenylglycine (DHPG) (50 μM) robustly upregulates T-channel current in the primary and apical tuft dendrite. Olfactory nerve stimulation generates a long-lasting depolarization, and we show that mGluRs recruit T channels to contribute ∼36% of the voltage integral of this depolarization. The long-lasting depolarization results in sustained firing and block of T channels decreased action potential firing by 84.1 ± 4.6%. Therefore upregulation of T channels by mGluRs is required for prolonged firing in response to olfactory nerve input.
Recognition Alters the Spatial Pattern of fMRI Activation in Early Retinotopic Cortex
Authors: Hsieh P.-J. , Vul E. , Kanwisher N.
Published: January 2010

Early retinotopic cortex has traditionally been viewed as containing a veridical representation of the low-level properties of the image, not imbued by high-level interpretation and meaning. Yet several recent results indicate that neural representations in early retinotopic cortex reflect not just the sensory properties of the image, but also the perceived size and brightness of image regions. Here we used functional magnetic resonance imaging pattern analyses to ask whether the representation of an object in early retinotopic cortex changes when the object is recognized compared with when the same stimulus is presented but not recognized. Our data confirmed this hypothesis: the pattern of response in early retinotopic visual cortex to a two-tone “Mooney” image of an object was more similar to the response to the full grayscale photo version of the same image when observers knew what the two-tone image represented than when they did not. Further, in a second experiment, high-level interpretations actually overrode bottom-up stimulus information, such that the pattern of response in early retinotopic cortex to an identified two-tone image was more similar to the response to the photographic version of that stimulus than it was to the response to the identical two-tone image when it was not identified. Our findings are consistent with prior results indicating that perceived size and brightness affect representations in early retinotopic visual cortex and, further, show that even higher-level information—knowledge of object identity—also affects the representation of an object in early retinotopic cortex.
Facilitation and Inhibition of Tibialis Anterior Responses to Corticospinal Stimulation After Maximal Voluntary Contractions
Authors: Giesebrecht Sabine , Martin Peter G. , Gandevia Simon C. , Taylor Janet L.
Published: January 2010

The corticospinal pathway is the major pathway controlling human voluntary movements. After strong voluntary contractions, the efficacy of corticospinal transmission to elbow flexors is reduced for ∼90 s, and this limits motoneuronal output. This reduction may reflect activity-dependent changes at cortico-motoneuronal synapses. We investigated whether similar changes occur in a leg muscle, tibialis anterior (TA). Electrical stimuli over high thoracic vertebrae activated corticospinal axons to evoke an EMG response in TA (TMEP). Stimuli were delivered before and after short 10-s and prolonged 1-min maximal contractions (MVCs) of ankle dorsiflexors. In two studies, stimuli were given with the muscle relaxed. In other studies, stimuli were given during weak contraction. After a 10-s MVC ( study 1, n = 10), TMEPs increased immediately to 349 ± 335% (mean ± SD) of control values. By 1 min after contraction, TMEPs decreased to 38 ± 28% of control and remained depressed for >10 min. Facilitation (191 ± 133% control) and depression (18 ± 22% control) occurred over the same time course after the 1-min MVC ( study 2, n = 10). When tested during weak contraction ( study 3, n = 10), TMEPs showed less facilitation (131 ± 41% control) and less depression (67 ± 21% control) and responses returned to baseline over ∼15 min. In contrast to TMEPs, H-reflexes in TA were little changed after a 10-s MVC ( study 4, n = 7). Our findings reveal an immediate facilitation and subsequent longer-lasting depression in corticospinal transmission to TA, which originate at a premotoneuronal site. This behavior differs markedly from that in elbow flexor muscles and suggests that activity-dependent changes in the motor pathway may be muscle specific.
Excitatory Action of GABA in the Terminal Nerve Gonadotropin-Releasing Hormone Neurons
Authors: Nakane Ryo , Oka Yoshitaka
Published: January 2010

The terminal nerve (TN)-gonadotropin-releasing hormone (GnRH) neurons have been suggested to function as a neuromodulatory system that regulates the motivational and arousal state of the animal and have served as a model system for the study of GnRH neuron physiology. To investigate the synaptic control of the TN-GnRH neurons, we analyzed electrophysiologically the effect of GABA on the TN-GnRH neurons. GABA generally hyperpolarizes most of the neurons in the adult brain by activating GABAA receptors while the activation of GABAA receptors depolarizes some specific neurons in the mature brain. Here we examined the GABAA receptor-mediated responses in the TN-GnRH neurons of adult teleost fish, the dwarf gourami, by means of gramicidin-perforated patch-clamp and cell-attached patch-clamp recordings. The reversal potential for the currents through GABAA receptors under the voltage clamp was depolarized relative to the resting membrane potential. GABAA receptor activation depolarized TN-GnRH neurons under the current clamp and had excitatory effect on their electrical activity, whereas the stronger GABAA receptor activation had bidirectional effect (excitatory–inhibitory). This excitatory effect is suggested to arise from high [Cl−]i and was shown to be suppressed by bumetanide, the blocker of Cl−-accumulating sodium-potassium-2-chloride co-transporter (NKCC). The present results demonstrate that GABAA receptor activation induces excitation in TN-GnRH neurons, which may facilitate their neuromodulatory functions by increasing their spontaneous firing frequencies. The excitatory actions of GABA in the adult brain have recently been attracting much attention, and the easily accessible large TN-GnRH neurons should be a nice model system to analyze their physiological functions.
Combined Use of MS2 and PP7 Coat Fusions Shows that TIA‐1 Dominates hnRNP A1 for K‐SAM Exon Splicing Control
Authors: Gesnel Marie-Claude , Del Gatto-Konczak Fabienne , Breathnach Richard
Published: January 2010

Splicing of the FGFR2 K‐SAM exon is repressed by hnRNP A1 bound to the exon and activated by TIA‐1 bound to the downstream intron. Both proteins are expressed similarly by cells whether they splice the exon or not, so it is important to know which one is dominant. To answer this question, we used bacteriophage PP7 and bacteriophage MS2 coat fusions to tether hnRNP A1 and TIA‐1 to distinct sites on the same pre‐mRNA molecule. hnRNP A1 fused to one coat protein was tethered to a K‐SAM exon containing the corresponding coat protein′s binding site. TIA‐1 fused to the other coat protein was tethered to the downstream intron containing that coat protein′s binding site. This led to efficient K‐SAM exon splicing. Our results show that TIA‐1 is dominant for K‐SAM exon splicing control and validate the combined use of PP7 and MS2 coat proteins for studying posttranscriptional events.
Testing Relationships between Energy and Vertebrate Abundance
Authors: Carbone Chris , Pettorelli Nathalie
Published: January 2010

Understanding what drives variation in the abundance of organisms is fundamental to evolutionary ecology and wildlife management. Yet despite its importance, there is still great uncertainty about the main factors influencing variation in vertebrate abundance across taxa. We believe valuable knowledge and increased predictive power could be gained by taking into account both the intrinsic factors of species and the extrinsic factors related to environmental surroundings in the commonly citedRQmodel, which provides a simple conceptual framework valid at both the interspecific and the intraspecific scales. Approaches comparing studies undertaken at different spatial and taxonomic scales could be key to our ability to better predict abundance, and thanks to the increased availability of population size data, global geographic datasets, and improved comparative methods, there might be unprecedented opportunities to (1) gain a greater understanding of vertebrate abundance patterns and (2) test existing theories on free-ranging animals.
Cold Exposure Exacerbates the Development of Diabetic Polyneuropathy in the Rat
Authors: Kasselman Lora J. , Veves Aristidis , Gibbons Christopher H. , Rutkove Seward B.
Published: January 2010

Diabetic polyneuropathy (DPN) and cold-induced nerve injury share several pathogenic mechanisms. This study explores whether cold exposure contributes to the development of DPN. Streptozotocin-induced diabetic rats and controls were exposed to a room temperature (23∘C) or cold environment (10∘C). H-reflex, tail and sciatic motor, and sensory nerve conduction studies were performed. Analyses of sural nerve, intraepidermal nerve fibers, and skin and nerve nitrotyrosine ELISAs were performed. Diabetic animals exposed to a cold environment had an increased H-reflex four weeks earlier than diabetic room temperature animals (P=.03). Cold-exposed diabetic animals also had greater reduction in motor conduction velocities at 20 weeks (P=.017), decreased skin nerve fiber density (P=.037), and increased skin nitrotyrosine levels (P=.047). Cold exposure appears to hasten the development of DPN in the rat STZ model of diabetes. These findings support that further study into the relationship between ambient temperature and DPN is warranted.
Serum Profiles of C-Reactive Protein, Interleukin-8, and Tumor Necrosis Factor- in Patients with Acute Pancreatitis
Authors: Digalakis Michael K. , Katsoulis Iraklis E. , Biliri Kalliopi , Themeli-Digalaki Katina
Published: January 2010

Background-Aims. Early prediction of the severity of acute pancreatitis would lead to prompt intensive treatment resulting in improvement of the outcome. The present study investigated the use of C-reactive protein (CRP), interleukin IL-8 and tumor necrosis factor- (TNF-) as prognosticators of the severity of the disease.Methods. Twenty-six patients with acute pancreatitis were studied. Patients with APACHE II score of 9 or more formed the severe group, while the mild group consisted of patients with APACHE II score of less than 9. Serum samples for measurement of CRP, IL-8 and TNF- were collected on the day of admission and additionally on the 2nd, 3rd and 7th days.Results. Significantly higher levels of IL-8 were found in patients with severe acute pancreatitis compared to those with mild disease especially at the 2nd and 3rd days ( and , resp.). No significant difference for CRP and TNF- was observed between the two groups. The optimal cut-offs for IL-8 in order to discriminate severe from mild disease at the 2nd and 3rd days were 25.4 pg/mL and 14.5 pg/mL, respectively.Conclusions. IL-8 in early phase of acute pancreatitis is superior marker compared to CRP and TNF- for distinguishing patients with severe disease.
Anti-EphA2 Antibodies with Distinct In Vitro Properties Have Equal In Vivo Efficacy in Pancreatic Cancer
Authors: Ansuini Helenia , Meola Annalisa , Gunes Zeynep , Paradisi Valentina , Pezzanera Monica , Acali Stefano , Santini Claudia , Luzzago Alessandra , Mori Federica , Lazzaro Domenico , Ciliberto Gennaro , Nicosia Alfredo , La Monica Nicola , Vitelli Alessandra
Published: January 2010

The EphA2 receptor tyrosine kinase is overexpressed in a variety of human epithelial cancers and is a determinant of malignant cellular behavior in pancreatic adenocarcinoma cells. Moreover, it is expressed in tumor endothelium and its activation promotes angiogenesis. To better clarify the therapeutic potential of monoclonal antibodies (mAbs) directed to the EphA2 receptor, we generated a large number of mAbs by differential screening of phage-Ab libraries by oligonucleotide microarray technology and implemented a strategy for the rapid identification of antibodies with the desired properties. We selected two high-affinity and highly specific EphA2 monoclonal antibodies with different in vitro properties on the human pancreatic tumor cell line MiaPaCa2. One is a potent EphA2-agonistic antibody, IgG25, that promotes receptor endocytosis and subsequent degradation, and the second is a ligand antagonist, IgG28, that blocks the binding to ephrin A1 and is cross-reactive with the mouse EphA2 receptor. We measured the effect of antibody treatment on the growth of MiaPaCa2 cells orthotopically transplanted in nude mice. Both IgG25 and IgG28 had strong antitumor and antimetastatic efficacy. In vivo treatment with IgG25 determined the reduction of the EphA2 protein levels in the tumor and the phosphorylation of FAK on Tyr576 while administration of IgG28 caused a decrease in tumor vascularization as measured by immunohistochemical analysis of CD31 in tumor sections. These data show that in a pancreatic cancer model comparable therapeutic efficacy is obtained either by promoting receptor degradation or by blocking receptor activation.
Activation-Induced T Helper Cell Death Contributes to Th1/Th2 Polarization following MurineSchistosoma japonicumInfection
Authors: Xu Xinyu , Wen Xiaoyun , Chi Ying , He Lei , Zhou Sha , Wang Xuefeng , Zhao Jiaqing , Liu Feng , Su Chuan
Published: January 2010

In chronic infectious diseases, such as schistosomiasis, pathogen growth and immunopathology are affected by the induction of a proper balanced Th1/Th2 response to the pathogen and by antigen-triggered activation-induced T cell death. Here, by usingS. japonicuminfection or schistosome antigens-immunized mouse model, or antigens in vitro stimulation, we report that during the early stage ofS. japonicuminfection, nonegg antigens trigger Th2 cell apoptosis via the granzyme B signal pathway, contributing to Th1 polarization, which is thought to be associated with worm clearance and severe schistosomiasis. Meanwhile, after the adult worms lay their eggs, the egg antigens trigger Th1 cell apoptosis via the caspase pathway, contributing to Th2 polarization, which is associated with mild pathology and enhanced survival of both worms and their hosts. Thus, our study suggests thatS. japonicumantigen-induced Th1 and Th2 cell apoptosis involves the Th1/Th2 shift and favorites both hosts and parasites.
Targeted Therapy in Ovarian Cancer
Authors: Willmott Lyndsay J. , Fruehauf John P.
Published: January 2010

Ovarian cancer is the most common cause of mortality of tumors from gynecologic origin and is often diagnosed after patients have already progressed to advanced disease stage. The current standard of care for treatment of ovarian cancer includes cytoreductive surgery followed by adjuvant chemotherapy. Unfortunately, many patients will recur and ultimately die from their disease. Targeted therapies have been evaluated in ovarian cancer as a method to overcome resistant disease. Angiogenesis inhibitors have shown success in many tumor types and have also demonstrated promise in trials involving patients with ovarian cancer. PARP inhibitors may be potentially active agents in patients with BRCA-associated ovarian cancer. Trials that have evaluated combinations of targeted agents have often revealed untoward toxicities, thus tempering enthusiasm for this approach.
Double‐Station Automatic Video Observation of the Meteors
Authors: Vítek Stanislav , Koten Pavel , Páta Petr , Fliegel Karel
Published: January 2010

The double station observation of the meteors by means of sensitive image intensifier technique started at the Ondrejov Observatory 10 years ago. The sensitivity of such instrumentation allows detection of the meteors down to masses of fractions of gram. Moreover, video technique provides us with a time resolution of the meteor events. On the other side, the precision of the video data is lower in comparison with the photographic data. We are introducing technological progress on the project—replacing of the S‐VHS camcorders with gigabite, ethernet cameras and making the whole process of video observation
automatic.
Metformin Improves Insulin Signaling in Obese Rats via Reduced IKKβAction in a Fiber-Type Specific Manner
Authors: Bikman Benjamin T. , Zheng Donghai , Kane Daniel A. , Anderson Ethan J. , Woodlief Tracey L. , Price Jesse W. , Dohm G. Lynis , Neufer P. Darrell , Cortright Ronald N.
Published: January 2010

Metformin is a widely used insulin-sensitizing drug, though its mechanisms are not fully understood. Metformin has been shown to activate AMPK in skeletal muscle; however, its effects on the inhibitor ofκB kinaseβ(IKKβ) in this same tissue are unknown. The aim of this study was to (1) determine the ability of metformin to attenuate IKKβaction, (2) determine whether changes in AMPK activity are associated with changes in IKKβaction in skeletal muscle, and (3) examine whether changes in AMPK and IKKβfunction are consistent with improved insulin signaling. Lean and obese male Zuckers received either vehicle or metformin by oral gavage daily for four weeks (four groups of eight). Proteins were measured in white gastrocnemius (WG), red gastrocnemius (RG), and soleus. AMPK phosphorylation increased (P<.05) in WG in both lean (57%) and obese (106%), and this was supported by an increase in phospho-ACC in WG. Further, metformin increased IκBαlevels in both WG (150%) and RG (67%) of obese rats, indicative of reduced IKKβactivity (P<.05), and was associated with reduced IRS1-pSer307(30%) in the WG of obese rats (P<.02). From these data we conclude that metformin treatment appears to exert an inhibitory influence on skeletal muscle IKKβactivity, as evidenced by elevated IκBαlevels and reduced IRS1-Ser307phosphorylation in a fiber-type specific manner.
Drug Combination Studies and Their Synergy Quantification Using the Chou-Talalay Method
Authors: Chou Ting-Chao
Published: January 2010

This brief perspective article focuses on the most common errors and pitfalls, as well as the do's and don'ts in drug combination studies, in terms of experimental design, data acquisition, data interpretation, and computerized simulation. The Chou-Talalay method for drug combination is based on the median-effect equation, derived from the mass-action law principle, which is the unified theory that provides the common link between single entity and multiple entities, and first order and higher order dynamics. This general equation encompasses the Michaelis-Menten, Hill, Henderson-Hasselbalch, and Scatchard equations in biochemistry and biophysics. The resulting combination index (CI) theorem of Chou-Talalay offers quantitative definition for additive effect (CI = 1), synergism (CI < 1), and antagonism (CI > 1) in drug combinations. This theory also provides algorithms for automated computer simulation for synergism and/or antagonism at any effect and dose level, as shown in the CI plot and isobologram, respectively. Cancer Res; 70(2); 440–6
E2F8 Contributes to Human Hepatocellular Carcinoma via Regulating Cell Proliferation
Authors: Deng Qing , Wang Qun , Zong Wei-Ying , Zheng Da-Li , Wen Yi-Xin , Wang Ke-Sheng , Teng Xiao-Mei , Zhang Xin , Huang Jian , Han Ze-Guang
Published: January 2010

The E2F family member of transcription factors includes the atypical member E2F8, which has been little studied in cancer. We report that E2F8 is strongly upregulated in human hepatocellular carcinoma (HCC), where it was evidenced to contribute to oncogenesis and progression. Ectopic overexpression of E2F8 promoted cell proliferation, colony formation, and tumorigenicity, whereas E2F8 knockdown inhibited these phenotypes, as documented in Huh-7, Focus, Hep3B, and YY-8103 HCC cell lines. Mechanistic analyses indicated that E2F8 could bind to regulatory elements of cyclin D1, regulating its transcription and promoting accumulation of S-phase cells. Together, our findings suggest that E2F8 contributes to the oncogenic potential of HCC and may constitute a potential therapeutic target in this disease. Cancer Res; 70(2); 782–91
Cell-Free Nucleic Acids Circulating in the Plasma of Colorectal Cancer Patients Induce the Oncogenic Transformation of Susceptible Cultured Cells
Authors: García-Olmo Dolores C. , Domínguez Carolina , García-Arranz Mariano , Anker Phillipe , Stroun Maurice , García-Verdugo José M. , García-Olmo Damián
Published: January 2010

It has been proposed that cell-free nucleic acids in the plasma participate in tumorigenesis and the development of metastases via transfection-like uptake of such nucleic acids by susceptible cells. This putative phenomenon is tentatively referred to as “genometastasis.” In the present study, we examined the effects on cultured cells of plasma from healthy individuals and from patients with colon cancer. Cultures of NIH-3T3 cells and human adipose-derived stem cells (hASC) were supplemented with samples of plasma from patients with K-ras–mutated colorectal tumors or from healthy subjects using two different protocols: direct addition of plasma to cultures in standard plates and addition in the absence of contact between plasma and cells, which were separated by a membrane with 0.4-μm pores. In plasma-treated hASCs, no K-ras–mutated sequences were detected by real-time PCR. In contrast, in most cultures of plasma-treated NIH-3T3 cells (murine cells), the transfer of human DNA occurred, as verified by the detection of human K-ras sequences, p53 sequences, and β-globin–encoding sequences. Moreover, NIH-3T3 cells that had been cultured with plasma from patients with colon cancer were oncogenically transformed, as shown by the development of carcinomas in nonobese diabetic–severe combined immunodeficient mice after the injection of such cells. Microscopic analysis of membranes that had separated plasma from cultured cells confirmed the complete absence of cells in the plasma. We only observed noncell particles, having diameters of <0.4 μm. Our results indicate that plasma from cancer patients is able to transform cultured cells oncogenically, supporting the previously proposed hypothesis of genometastasis. Cancer Res; 70(2); 560–7
Time to Treatment Response in Patients with Follicular Lymphoma Treated with Bortezomib Is Longer Compared with Other Histologic Subtypes
Authors: O'Connor Owen A. , Portlock Carol , Moskowitz Craig , Hamlin Paul , Straus David , Gerecitano John , Gonen Mithat , Dumitrescu Otilia , Sarasohn Debra , Butos John , Neylon Ellen , Mac-Gregor Cortelli Barbara , Blumel Susan , Evens Andrew M. , Zelenetz Andrew D. , Wright John , Cooper Brenda , Winter Jane , Vose Julie
Published: January 2010

Purpose: To determine the antitumor activity of the novel proteasome inhibitor bortezomib in patients with indolent non–Hodgkin's lymphoma.

Experimental Design: Patients with follicular lymphoma (FL), marginal zone lymphoma, mantle cell lymphoma, small lymphocytic lymphoma/chronic lymphocytic leukemia, and Waldenstrom's macroglobulinemia were eligible for study. Bortezomib was given at a dose of 1.5 mg/m2 as an i.v. push on days 1, 4, 8, and 11 of a 21-day cycle. Eligibility included the following: (a) no more than three prior therapies, (b) at least 1 month since prior chemotherapy, (c) measurable disease, and (d) an absolute neutrophil count of >1,000/μL and a platelet count >50,000/μL for the first dose of any cycle.

Results: Seventy-seven patients were registered, of which 69 were assessable for response based on the completion of two cycles of therapy. Subtypes included FL (59.5%), mantle cell lymphoma (52%), small lymphocytic lymphoma/chronic lymphocytic leukemia (16.2%), marginal zone lymphoma (21.6%), and one Waldenstrom's macroglobulinemia. The median number of prior therapies was three. The most common grade 3 toxicity was lymphopenia (35%) and thrombocytopenia (31%). Twenty-five patients experienced grade ≤2 sensory neuropathy (32), and 8% experienced grade 3 neurosensory toxicity. The overall response rate was 45% (40% on an intention to treat) including 10 complete remissions. Of 18 patients with FL, 9 responded with 4 complete response. The median time to treatment response for FL was 12 weeks, whereas the median time to treatment response for other subtypes of non–Hodgkin's lymphoma was only 4 weeks.

Conclusions: These data suggest that bortezomib has significant single agent activity in patients with FL, and that longer durations of treatment may improve overall response. Clin Cancer Res; 16(2); 719–26
GSK690693 Delays Tumor Onset and Progression in Genetically Defined Mouse Models Expressing Activated Akt
Authors: Altomare Deborah A. , Zhang Lili , Deng Jing , Di Cristofano Antonio , Klein-Szanto Andres J. , Kumar Rakesh , Testa Joseph R.
Published: January 2010

Purpose: Akt plays a central role in regulating tumor cell survival and cell cycle progression and is regarded as a promising therapeutic target. We used genetically defined mouse models that develop spontaneous tumors exhibiting activated Akt to determine if Akt inhibition by GSK690693 is effective in the treatment of cancer. The broad long-term objective of this project was to use preclinical cancer models with precisely defined genetic lesions to elucidate the efficacy of targeting Akt with GSK690693.

Experimental Design: We tested the in vivo effects of GSK690693 in Lck-MyrAkt2 transgenic mice that develop lymphomas, heterozygous Pten+/− knockout mice that exhibit endometrial tumors, and TgMISIIR-TAg-DR26 mice that develop ovarian carcinomas, all of which exhibit hyperactivation of Akt. In addition to standard disease onset and histology, tumors arising in treated animals were examined by immunohistochemistry to verify downregulated Akt signaling relative to placebo-treated mice. When possible, drug response was evaluated in tumor cell cultures by standard proliferation and apoptosis assays and by immunoblotting with various phosphospecific antibodies.

Results: GSK690693 exhibited efficacy irrespective of the mechanism of Akt activation involved. Interestingly, GSK690693 was most effective in delaying tumor progression in Lck-MyrAkt2 mice expressing a membrane-bound, constitutively active form of Akt. Both tumors and primary cell cultures displayed downregulation of the Akt pathway, increased apoptosis, and primarily decreased cell proliferation.

Conclusion: These results suggest that GSK690693 or other Akt inhibitors might have therapeutic efficacy in human cancers with hyperactivated Akt and/or a dependence on Akt signaling for tumor progression. Clin Cancer Res; 16(2); 486–96
Mechanisms of Inactivation of PTCH1 Gene in Nevoid Basal Cell Carcinoma Syndrome: Modification of the Two-Hit Hypothesis
Authors: Pan Shuang , Dong Qing , Sun Li-Sha , Li Tie-Jun
Published: January 2010

Purpose: PTCH1 has been identified as the gene responsible for nevoid basal cell carcinoma syndrome (NBCCS). Keratocystic odontogenic tumors (KCOT) are aggressive jaw lesions that may occur in isolation or in association with NBCCS. The aim of this study was to investigate the genetic and/or epigenetic mechanisms of inactivation of the PTCH1 gene in patients with NBCCS and related sporadic KCOTs.

Experimental Design: Loss of heterozygosity was analyzed in 44 patients (15 NBCCS-related and 29 sporadic KCOTs), all of whom were previously analyzed for PTCH1 mutations. Allelic location was established in tumors carrying two coincident mutations. PTCH1 mRNA expression and promoter methylation status were analyzed in a panel of KCOTs to define the possible role of epigenetic effects on PTCH1 inactivation.

Results: Although mutations and loss of heterozygosity of PTCH1 were frequently detected in both syndromic and nonsyndromic cases, hypermethylation of the PTCH1 promoter was not identified in the present series. Of all the 44 cases examined, 13 were identified to fit the two-hit model, 14 to conform to a one-hit model, and the remaining 17 cases showing no alteration in PTCH1. The distribution of two-hit, one-hit, and non-hit cases was significantly different between syndrome and nonsyndrome patients (P < 0.02).

Conclusions: This study indicates that PTCH1 gene alternation may play a significant role in the pathogenesis of NBCCS and the related sporadic tumors. Not only the standard two-hit model, but also haploinsufficiency or dominant-negative isoforms may be implicated in the inactivation of the PTCH1 gene. Clin Cancer Res; 16(2); 442–50
Individualizing Dosing of Irinotecan
Authors: Ratain Mark J. , Innocenti Federico
Published: January 2010

Individualized drug dosing is a longstanding goal of clinical pharmacologists. Given the narrow therapeutic index of most anticancer agents, it is plausible that this approach would be of particular value in oncology. Irinotecan is an interesting agent for individualized dosing, given its complex metabolism and increasing knowledge of its pharmacokinetics predictors. Clin Cancer Res; 16(2); 371–2
The influence of the menstrual cycle, normal pregnancy and pre-eclampsia on platelet activation
Authors: Robb Amy , Din Jehangir , Mills Nicholas , Smith Imogen , Blomberg Anders , Zikry Mariam , Raftis Jennifer , Newby David , Denison Fiona
Published: January 2010

Platelet activation has a key role in mediating thrombotic and inflammatory events. This study aimed to determine the influence of the menstrual cycle, pregnancy and preeclampsia on in vivo platelet activation. Twelve healthy nulliparous, non-smoking women with regular menses were studied over a single menstrual cycle. Twenty-one healthy primigravida pregnant women were studied longitudinally at 16, 24, 32 and 37 weeks gestation and seven weeks post-partum. Sixteen primigravida women with preeclampsia were studied at time of diagnosis and at seven weeks post-partum. Platelet-monocyte aggregates and platelet-surface P-selectin expression were assessed by flow-cytometry. Soluble P-selectin and CD40 ligand (CD40L) were measured by ELISA. Markers of platelet activation did not vary over the menstrual cycle. Platelet-monocyte aggregates were greater in the third trimester of pregnancy compared to non-pregnant women (p=0.003). Platelet surface and plasma soluble P-selectin concentrations increased with gestation (p<0.0001) and were raised by 24 weeks of pregnancy compared to non-pregnant women (p≤0.02 for both) and together with platelet monocyte aggregates, decreased post-partum (p≤0.02). Soluble CD40L concentrations fell in pregnancy, reaching a nadir at mid-gestation (p=0.002). There were no differences in markers of platelet activation between normal and pre-eclamptic pregnancies. In conclusion, platelet activation is increased in pregnancy and increases with gestation but is unaffected by preeclampsia. This suggests that systemic platelet activation is a feature of pregnancy but this is not affected by established preeclampsia.
Effect of two doses of aspirin on thromboxane biosynthesis and platelet function in patients undergoing coronary surgery
Authors: Brambilla Marta , Parolari Alessandro , Camera Marina , Colli Susanna , Eligini Sonia , Centenaro Chiara , Anselmo Achille , Alamanni Francesco , Tremoli Elena
Published: January 2010

Early post-operative aspirin improves survival in patients undergoing coronary artery bypass graft (CABG). However, most patients do not benefit of aspirin after CABG, still remaining at risk of thrombotic events due to insufficient platelet inhibition, specifically via the thromboxane (TX) pathway. We evaluated the effect of two aspirin doses (100 or 325 mg daily, enteric coated formulations) on platelet function and TX biosynthesis in patients after CABG and assessed whether the incidence of residual platelet reactivity could be reduced by the higher dose. Fifty-six patients undergoing CABG were randomly assigned to 100 or 325 mg aspirin daily for five days in a prospective single-centre study. Treatment effect was assessed by measuring either platelet function (light-transmission aggregometry and point-of-care PFA-100®) or TX biosynthesis in collagen-stimulated platelets, serum, urine, and in lipopolysaccharide (LPS)-cultured whole blood (WB). An insufficient TX inhibition was observed with 100 mg aspirin but not with the higher dose. The different effect of the two doses was, however, highlighted by either TX (platelet- or serum-derived) or by PFA-100® but not by the other assays. In conclusion, early after CABG, the incidence of residual platelet activity was lower in patients who received 325 mg aspirin. Moreover, evidence was provided that different methods yield different results in the detection of aspirin resistance, rendering them not interchangeable.
Safety and tolerability of an immediate-release formulation of the oral direct thrombin inhibitor AZD0837 in the prevention of stroke and systemic embolism in patients with atrial fibrillation
Authors: Rasmussen Lars , Tveit Arnljot , Jensen Eva , Wessman Peter , Panfilov Seva , Wåhlander Karin , Olsson Bertil
Published: January 2010

AZD0837 is an investigational oral anticoagulant which is converted to the active form, AR-H067637, a selective direct thrombin inhibitor. The present study, a multicentre, randomised, parallel-group, dose-guiding study, assessed the safety and tolerability of an immediate-release formulation of AZD0837 compared with dose-adjusted warfarin in the prevention of stroke and systemic embolic events in atrial fibrillation (AF) patients. Two hundred fifty AF patients with at least one additional risk factor for stroke were randomised to receive either immediate-release AZD0837 (150 mg twice daily [bid] or 350 mg bid, blinded treatment) or dose-adjusted warfarin (international normalised ratio 2.0–3.0, open treatment) for three months. The safety and tolerability of 150 mg bid AZD0837 appeared to be as good as that of warfarin. Total bleeding events were six with 150 mg bid AZD0837, 15 with 350 mg bid AZD0837 and eight with warfarin. Alanine aminotransferase elevations (> 3 x upper limit of normal) were infrequent, without apparent differences between treatment groups. A numerically higher incidence of serious adverse events was observed with 350 mg bid AZD0837 compared with 150 mg bid, with six of 13 being cardiac related, all with different diagnoses. An increase in mean serum creatinine of approximately 10% was observed in both AZD0837 groups, which returned to baseline after completion of therapy. There were no strokes, transient ischaemic attacks or cerebral haemorrhages with any of the treatments. In conclusion, the safety and tolerability of 150 mg bid immediate-release AZD0837 appeared to be as good as that of dose-adjusted warfarin. However, larger studies will be needed to define the safety profile of AZD0837.