bluuebunny/crossref_metadata_2025 huggingface dataset:
Binding of ligands originates small perturbations on the microscopic thermodynamic properties of a multicentre redox protein
Authors: Salgueiro Carlos A. , Morgado Leonor , Fonseca Bruno , Lamosa Pedro , Catarino Teresa , Turner David L. , Louro Ricardo O.
Published: April 2005

NMR and visible spectroscopy coupled to redox measurements were used to determine the equilibrium thermodynamic properties of the four haems in cytochrome c3 under conditions in which the protein was bound to ligands, the small anion phosphate and the protein rubredoxin with the iron in the active site replaced by zinc. Comparison of these results with data for the isolated cytochrome shows that binding of ligands causes only small changes in the reduction potentials of the haems and their pairwise interactions, and also that the redox‐sensitive acid–base centre responsible for the redox–Bohr effect is essentially unaffected. Although neither of the ligands tested is a physiological partner of cytochrome c3, the small changes observed for the thermodynamic properties of cytochrome c3 bound to these ligands vs. the unbound state, indicate that the thermodynamic properties measured for the isolated protein are relevant for a physiological interpretation of the role of this cytochrome in the bioenergetic metabolism of Desulfovibrio.
Protein families and RNA recognition
Authors: Chen Yu , Varani Gabriele
Published: April 2005

This minireview series examines the structural principles underlying the biological function of RNA‐binding proteins. The structural work of the last decade has elucidated the structures of essentially all the major RNA‐binding protein families; it has also demonstrated how RNA recognition takes place. The ribosome structures have further integrated this knowledge into principles for the assembly of complex ribonucleoproteins. Structural and biochemical work has revealed unexpectedly that several RNA‐binding proteins bind to other proteins in addition to RNA or instead of RNA. This tremendous increase in the structural knowledge has expanded not only our understanding of the RNA recognition principle, but has also provided new insight into the biological function of these proteins and has helped to design better experiments to understand their biological roles.
The double‐stranded RNA‐binding motif, a versatile macromolecular docking platform
Authors: Chang Kung‐Yao , Ramos Andres
Published: April 2005

The double‐stranded RNA‐binding motif (dsRBM) is an αβββα fold with a well‐characterized function to bind structured RNA molecules. This motif is widely distributed in eukaryotic proteins, as well as in proteins from bacteria and viruses. dsRBM‐containing proteins are involved in processes ranging from RNA editing to protein phosphorylation in translational control and contain a variable number of dsRBM domains. The structural work of the past five years has identified a common mode of RNA target recognition by dsRBMs and dissected this recognition into two functionally separated interaction modes. The first involves the recognition of specific moieties of the RNA A‐form helix by two protein loops, while the second is based on the interaction between structural elements flanking the RNA duplex with the first helix of the dsRBM. The latter interaction can be tuned by other protein elements. Recent work has made clear that dsRBMs can also recognize non‐RNA targets (proteins and DNA), and act in combination with other dsRBMs and non‐dsRBM motifs to play a regulatory role in catalytic processes. The elucidation of functional networks coordinated by dsRBM folds will require information on the precise functional relationship between different dsRBMs and a clarification of the principles underlying dsRBM–protein recognition.
γN‐crystallin and the evolution of the βγ‐crystallin superfamily in vertebrates
Authors: Wistow Graeme , Wyatt Keith , David Larry , Gao Chun , Bateman Orval , Bernstein Steven , Tomarev Stanislav , Segovia Lorenzo , Slingsby Christine , Vihtelic Thomas
Published: April 2005

The β and γ crystallins are evolutionarily related families of proteins that make up a large part of the refractive structure of the vertebrate eye lens. Each family has a distinctive gene structure that reflects a history of successive gene duplications. A survey of γ‐crystallins expressed in mammal, reptile, bird and fish species (particularly in the zebrafish, Danio rerio) has led to the discovery of γN‐crystallin, an evolutionary bridge between the β and γ families. In all species examined, γN‐crystallins have a hybrid gene structure, half β and half γ, and thus appear to be the ‘missing link’ between the β and γ crystallin lineages. Overall, there are four major classes of γ‐crystallin: the terrestrial group (including mammalian γA–F); the aquatic group (the fish γM‐crystallins); the γS group; and the novel γN group. Like the evolutionarily ancient β‐crystallins (but unlike the terrestrial γA–F and aquatic γM groups), both the γS and γN crystallins form distinct clades with members in fish, reptiles, birds and mammals. In rodents, γN is expressed in nuclear fibers of the lens and, perhaps hinting at an ancestral role for the γ‐crystallins, also in the retina. Although well conserved throughout vertebrate evolution, γN in primates has apparently undergone major changes and possible loss of functional expression.
Control analysis as a tool to understand the formation of the las operon in Lactococcus lactis
Authors: Koebmann Brian , Solem Christian , Jensen Peter Ruhdal
Published: April 2005

In Lactococcus lactis the enzymes phosphofructokinase (PFK), pyruvate kinase (PK) and lactate dehydrogenase (LDH) are uniquely encoded in the las operon. We used metabolic control analysis to study the role of this organization. Earlier studies have shown that, at wild‐type levels, LDH has no control over glycolysis and growth rate, but high negative control over formate production (). We found that PFK and PK exert no control over glycolysis and growth rate at wild‐type enzyme levels but both enzymes exert strong positive control on the glycolytic flux at reduced activities. PK exerts high positive control over formate () and acetate production (), whereas PFK exerts no control over these fluxes at increased expression. Decreased expression of the entire las operon resulted in a strong decrease in the growth rate and glycolytic flux; at 53% expression of the las operon glycolytic flux was reduced to 44% and the flux control coefficient increased towards 3. Increased las expression resulted in a slight decrease in the glycolytic flux. At wild‐type levels, control was close to zero on both glycolysis and the pyruvate branches. The sum of control coefficients for the three enzymes individually was comparable with the control coefficient found for the entire operon; the strong positive control exerted by PK almost cancels out the negative control exerted by LDH on formate production. Our analysis suggests that coregulation of PFK and PK provides a very efficient way to regulate glycolysis, and coregulating PK and LDH allows cells to maintain homolactic fermentation during glycolysis regulation.
Functional evidence for cone‐specific connectivity in the human retina
Authors: Vakrou Chara , Whitaker David , McGraw Paul V. , McKeefry Declan
Published: April 2005

Physiological studies of colour vision have not yet resolved the controversial issue of how chromatic opponency is constructed at a neuronal level. Two competing theories, the cone‐selective hypothesis and the random‐wiring hypothesis, are currently equivocal to the architecture of the primate retina. In central vision, both schemes are capable of producing colour opponency due to the fact that receptive field centres receive input from a single bipolar cell – the so called ‘private line arrangement’. However, in peripheral vision this single‐cone input to the receptive field centre is lost, so that any random cone connectivity would result in a predictable reduction in the quality of colour vision. Behavioural studies thus far have indeed suggested a selective loss of chromatic sensitivity in peripheral vision. We investigated chromatic sensitivity as a function of eccentricity for the cardinal chromatic (L/M and S/(L + M)) and achromatic (L + M) pathways, adopting stimulus size as the critical variable. Results show that performance can be equated across the visual field simply by a change of scale (size). In other words, there exists no qualitative loss of chromatic sensitivity across the visual field. Critically, however, the quantitative nature of size dependency for each of the cardinal chromatic and achromatic mechanisms is very specific, reinforcing their independence in terms of anatomy and genetics. Our data provide clear evidence for a physiological model of primate colour vision that retains chromatic quality in peripheral vision, thus supporting the cone‐selective hypothesis.
Timing‐dependent plasticity in human primary somatosensory cortex
Authors: Wolters Alexander , Schmidt Arne , Schramm Axel , Zeller Daniel , Naumann Markus , Kunesch Erwin , Benecke Reiner , Reiners Karlheinz , Classen Joseph
Published: April 2005

Animal experiments suggest that cortical sensory representations may be remodelled as a consequence of changing synaptic efficacy by timing‐dependent associative neuronal activity. Here we describe a timing‐based associative form of plasticity in human somatosensory cortex. Paired associative stimulation (PAS) was performed by combining repetitive median nerve stimulation with transcranial magnetic stimulation (TMS) over the contralateral postcentral region. PAS increased exclusively the amplitude of the P25 component of the median nerve‐evoked somatosensory‐evoked potential (MN‐SSEP), which is probably generated in the superficial cortical layers of area 3b. SSEP components reflecting neuronal activity in deeper cortical layers (N20 component) or subcortical regions (P14 component) remained constant. PAS‐induced enhancement of P25 amplitude displayed topographical specificity both for the recording (MN‐SSEP versus tibial nerve‐SSEP) and the stimulation (magnetic stimulation targeting somatosensory versus motor cortex) arrangements. Modulation of P25 amplitude was confined to a narrow range of interstimulus intervals (ISIs) between the MN pulse and the TMS pulse, and the sign of the modulation changed with ISIs differing by only 15 ms. The function describing the ISI dependence of PAS effects on somatosensory cortex resembled one previously observed in motor cortex, shifted by ∼7 ms. The findings suggest a simple model of modulation of excitability in human primary somatosensory cortex, possibly by mechanisms related to the spike‐timing‐dependent plasticity of neuronal synapses located in upper cortical layers.
Dynamic synapses as archives of synaptic history: state‐dependent redistribution of synaptic efficacy in the rat hippocampal CA1
Authors: Yasui Takuya , Fujisawa Shigeyoshi , Tsukamoto Masako , Matsuki Norio , Ikegaya Yuji
Published: April 2005

Plastic modifications of synaptic strength are putative mechanisms underlying information processing in the brain, including memory storage, signal integration and filtering. Here we describe a dynamic interplay between short‐term and long‐term synaptic plasticity. At rat hippocampal CA1 synapses, induction of both long‐term potentiation (LTP) and depression (LTD) was accompanied by changes in the profile of short‐term plasticity, termed redistribution of synaptic efficacy (RSE). RSE was presynaptically expressed and associated in part with a persistent alteration in hyperpolarization‐activated Ih channel activity. Already potentiated synapses were still capable of showing RSE in response to additional LTP‐triggering stimulation. Strikingly, RSE took place even after reversal of LTP or LTD, that is, the same synapse can display different levels of short‐term plasticity without changing synaptic efficacy for the initial spike in burst presynaptic firing, thereby modulating spike transmission in a firing rate‐dependent manner. Thus, the history of long‐term synaptic plasticity is registered in the form of short‐term plasticity, and RSE extends the information storage capacity of a synapse and adds another dimension of functional complexity to neuronal operations.
Inhibition of sarcoplasmic reticular function by chronic interleukin‐6 exposure via iNOS in adult ventricular myocytes
Authors: Yu Xin‐Wen , Chen Qian , Kennedy Richard H. , Liu Shi J.
Published: April 2005

Interleukin (IL)‐6 has been shown to decrease cardiac contractility via a nitric oxide synthase (NOS)‐dependent pathway during acute exposure. We previously reported that IL‐6 decreases contractility and increases inducible NOS (iNOS) in adult rat ventricular myocytes (ARVM) after 2 h exposure. The goal of this study was to investigate the cellular mechanism underlying this chronic IL‐6‐induced negative inotropy and the role of iNOS. Pretreatment for 2 h with 10 ng ml−1 IL‐6 decreased the kinetics of cell shortening (CS) and contractile responsiveness to Ca2+o ([Ca2+]o from 0 to 2 mm) in ARVM. We first examined whether IL‐6 reduced Ca2+ influx via L‐type Ca2+‐channel current (ICa,L). Whole‐cell ICa,L in ARVM was measured under conditions similar to those used for CS measurements, and it was found to be unaltered by IL‐6. The sarcoplasmic reticular (SR) function was then assessed by examining postrest potentiation (PRP) and caffeine responsiveness of CS. Results showed that treatment with IL‐6 for 2 h significantly decreased PRP, which was concomitant with a decrease in the phosphorylation of phospholamban. Following removal of IL‐6, PRP and responsiveness to 10 mm caffeine were also reduced. Meanwhile, the IL‐6‐induced increase in nitric oxide (NO) production after 2 h (but not 1 h) was abolished by NG‐monomethyl‐l‐arginine (l‐NMMA) and 2‐amino‐5,6‐dihydro‐6‐methyl‐4H‐1,3‐thiazine (AMT; a selective inhibitor of iNOS). Furthermore, IL‐6‐elicited suppressions of PRP and responsiveness to caffeine and Ca2+o were abolished by L‐NMMA and AMT. Thus, these results suggest that activation of iNOS mediates IL‐6‐induced inhibition of SR function in ARVM during chronic exposure.
Unmasking group III metabotropic glutamate autoreceptor function at excitatory synapses in the rat CNS
Authors: Billups Brian , Graham Bruce P. , Wong Adrian Y. C. , Forsythe Ian D.
Published: April 2005

Presynaptic group III metabotropic glutamate receptor (mGluR) activation by exogenous agonists (such as l‐2‐amino‐4‐phosphonobutyrate (l‐AP4)) potently inhibit transmitter release, but their autoreceptor function has been questioned because endogenous activation during high‐frequency stimulation appears to have little impact on synaptic amplitude. We resolve this ambiguity by studying endogenous activation of mGluRs during trains of high‐frequency synaptic stimuli at the calyx of Held. In vitro whole‐cell patch recordings were made from medial nucleus of the trapezoid body (MNTB) neurones during 1 s excitatory postsynaptic current (EPSC) trains delivered at 200 Hz and at 37°C. The group III mGluR antagonist (R,S)‐cyclopropyl‐4‐phosphonophenylglycine (CPPG, 300 μm) had no effect on EPSC short‐term depression, but accelerated subsequent recovery time course (τ: 4.6 ± 0.8 s to 2.4 ± 0.4 s, P= 0.02), and decreased paired pulse ratio from 1.18 ± 0.06 to 0.97 ± 0.03 (P= 0.01), indicating that mGluR activation reduced release probability (P). Modelling autoreceptor activation during repetitive stimulation revealed that as P declines, the readily releasable pool size (N) increases so that the net EPSC (NP) is unchanged and short‐term depression proceeds with the same overall time course as in the absence of autoreceptor activation. Thus, autoreceptor action on the synaptic response is masked but the synapse is now in a different state (lower P, higher N). While vesicle replenishment clearly underlies much of the recovery from short‐term depression, our results show that the recovery time course of P also contributes to the reduced response amplitude for 1–2 s. The results show that passive equilibration between N and P masks autoreceptor modulation of the EPSC and suggests that mGluR autoreceptors function to change the synaptic state and distribute metabolic demand, rather than to depress synaptic amplitude.
Cytoskeletal regulation of calcium‐permeable cation channels in the human syncytiotrophoblast: role of gelsolin
Authors: Montalbetti Nicolás , Li Qiang , Timpanaro Gustavo A. , González‐Perrett Silvia , Dai Xiao‐Qing , Chen Xing‐Zhen , Cantiello Horacio F.
Published: April 2005

The human syncytiotrophoblast (hST) is the most apical epithelial barrier that covers the villous tree of the human placenta. An intricate and highly organized network of cytoskeletal structures supports the hST. Recently, polycystin‐2 (PC2), a TRP‐type nonselective cation channel, was functionally observed in hST, where it may be an important player to Ca2+ transport. Little is known, however, about channel regulation in hST. In this report, the regulatory role of actin dynamics on PC2 channels reconstituted from hST apical membranes was explored. Acute addition of cytochalasin D (CD, 5 μg ml−1) to reconstituted hST apical membranes transiently increased K+‐permeable channel activity. The actin‐binding proteins α‐actinin and gelsolin, as well as PC2, were observed by Western blot and immunofluorescence analyses in hST vesicles. CD treatment of hST vesicles resulted in a re‐distribution of actin filaments, in agreement with the effect of CD on K+ channel activity. In contrast, addition of exogenous monomeric actin, but not prepolymerized actin, induced a rapid inhibition of channel function in hST. This inhibition was obliterated by the presence of CD in the medium. The acute (<15 min) CD stimulation of K+ channel activity was mimicked by addition of the actin‐severing protein gelsolin in the presence, but not in the absence, of micromolar Ca2+. Ca2+ transport through PC2 triggers a regulatory feedback mechanism, which is based on the severing and re‐formation of filamentous actin near the channels. Cytoskeletal structures may thus be relevant to ion transport regulation in the human placenta.
Theta‐burst repetitive transcranial magnetic stimulation suppresses specific excitatory circuits in the human motor cortex
Authors: Di Lazzaro V. , Pilato F. , Saturno E. , Oliviero A. , Dileone M. , Mazzone P. , Insola A. , Tonali P. A. , Ranieri F. , Huang Y. Z. , Rothwell J. C.
Published: April 2005

In four conscious patients who had electrodes implanted in the cervical epidural space for the control of pain, we recorded corticospinal volleys evoked by single‐pulse transcranial magnetic stimulation (TMS) over the motor cortex before and after a 20 s period of continuous theta‐burst stimulation (cTBS). It has previously been reported that this form of repetitive TMS reduces the amplitude of motor‐evoked potentials (MEPs), with the maximum effect occurring at 5–10 min after the end of stimulation. The present results show that cTBS preferentially decreases the amplitude of the corticospinal I1 wave, with approximately the same time course. This is consistent with a cortical origin of the effect on the MEP. However, other protocols that lead to MEP suppression, such as short‐interval intracortical inhibition, are characterized by reduced excitability of late I waves (particularly I3), suggesting that cTBS suppresses MEPs through different mechanisms, such as long‐term depression in excitatory synaptic connections.
Obesity and Metabolic Syndrome in Circadian
Clock
Mutant Mice
Authors: Turek Fred W. , Joshu Corinne , Kohsaka Akira , Lin Emily , Ivanova Ganka , McDearmon Erin , Laposky Aaron , Losee-Olson Sue , Easton Amy , Jensen Dalan R. , Eckel Robert H. , Takahashi Joseph S. , Bass Joseph
Published: April 2005

The CLOCK transcription factor is a key component of the molecular circadian clock within pacemaker neurons of the hypothalamic suprachiasmatic nucleus. We found that homozygous
Clock
mutant mice have a greatly attenuated diurnal feeding rhythm, are hyperphagic and obese, and develop a metabolic syndrome of hyperleptinemia, hyperlipidemia, hepatic steatosis, hyperglycemia, and hypoinsulinemia. Expression of transcripts encoding selected hypothalamic peptides associated with energy balance was attenuated in the
Clock
mutant mice. These results suggest that the circadian clock gene network plays an important role in mammalian energy balance.
Low bone mineral density is two to three times more prevalent in non-athletic premenopausal women than in elite athletes: a comprehensive controlled study
Authors: Torstveit M K , Sundgot-Borgen J
Published: April 2005

Objective:To compare bone mineral density (BMD), investigate factors associated with BMD, and examine the prevalence of low BMD in athletes and non-athletic controls.

Methods:The study included a questionnaire (part I), measurement of BMD (part II), and a clinical interview (part III). All Norwegian female athletes on national teams (n = 938) and an aged matched random sample of non-athletic controls (n = 900) were invited to participate. The questionnaire was completed by 88% of athletes and 70% of controls. A random sample of these athletes (n = 300) and controls (n = 300) was invited to participate in parts II and III. All parts were completed by 186 athletes (62%) and 145 controls (48%).

Results:Mean (standard deviation) total body (TB) BMD was higher (p<0.001) in athletes (1.21 (0.09) g/cm2) than in controls (1.18 (0.08) g/cm2), and higher (p<0.001) in high impact (HI) sports athletes than in medium impact (MI) and low impact (LI) sports athletes. In athletes, body weight and impact loading sports were positively associated, and percent body fat and eating disorders were negatively associated with TB BMD. Body weight and weight bearing activities were positively associated and menstrual dysfunction was negatively associated with TB BMD in controls. A higher percentage of controls (28.3%) than athletes (10.7%) had low BMD (p<0.001).

Conclusion:Female elite athletes have 3–20% higher BMD than non-athletic controls and HI sports athletes have 3–22% higher BMD compared with MI and LI sports athletes. Low BMD is two to three times more common in non-athletic premenopausal women than in elite athletes.
Craniomaxillofacial injury in sport: a review of prevention research
Authors: Echlin P S , Upshur R E G , Peck D M , Skopelja E N
Published: April 2005

Current decision making in prevention of sport related craniomaxillofacial injury is based on available data derived from surveillance and attitude based studies. The literature on this type of injury prevention lacks the high quality scientific design and evidence on which mandatory interventions can be based. Currently available prevention methodology can provide a better understanding of injury mechanisms and produce valid interventions.
Development and initial validation of the Brunel lifestyle physical activity questionnaire
Authors: Karageorghis C I , Vencato M M , Chatzisarantis N L D , Carron A V
Published: April 2005

Objectives:To develop a valid and reliable internet based lifestyle physical activity questionnaire suitable for use among the United Kingdom population.

Methods:After a detailed content analysis and item generation using a panel of experts, an internet based measure of lifestyle physical activity behaviour was developed. Data were collected from 1369 subjects in total. Confirmatory factor analysis was used to examine the two subscales of the Brunel lifestyle physical activity questionnaire among independent samples and by use of multisample analyses.

Results:The confirmatory factor analysis showed the psychometric integrity of two subscales: planned physical activity and unplanned physical activity.

Conclusion:The questionnaire is a valid and reliable instrument designed to provide an online behavioural assessment to be used in conjunction with a 12 week personalised fitness programme delivered through the internet.
High prevalence of jumper’s knee and sonographic changes in Swedish elite junior volleyball players compared to matched controls
Authors: Gisslèn K , Gyulai C , Söderman K , Alfredson H
Published: April 2005

Background:Jumper’s knee is a common and troublesome condition among senior volleyball players, but its prevalence among elite junior players compared to matched non-sports active controls is not known.

Objective:To clinically, and by sonography, examine the patellar tendons in elite junior volleyball players (15–19 years) at the Swedish National Centre for volleyball and in matched controls.

Methods:The patellar tendons in the 57 students at the Swedish National Centre for high school volleyball and in 55 age, height, and weight matched not regularly sports active controls were evaluated clinically and by grey scale ultrasonography (US) and power Doppler (PD) sonography.

Results:There were no significant differences in mean age, height, and weight between the volleyball players and the controls. In the volleyball group, jumper’s knee was diagnosed clinically and by US in 12 patellar tendons (10 male and two female). In 12/12 tendons, PD sonography demonstrated a neovascularisation in the area with structural tendon changes. In another 10 pain free tendons, there were structural tendon changes and neovessels. In the control group, no individual had a clinical diagnosis of jumper’s knee. US demonstrated structural tendon changes in 11 tendons, but there was no neovascularisation on PD sonography.

Conclusions:A clinical diagnosis of jumper’s knee, together with structural tendon changes and neovascularisation visualised with sonography, was seen among Swedish elite junior volleyball players but not in matched not regularly sports active controls. Structural tendon change alone was seen in 10% of the control tendons.
Posterior sternoclavicular dislocation in a rugby player as a cause of silent vascular compromise: a case report
Authors: Mirza A H , Alam K , Ali A
Published: April 2005

Background:Approximately 120 cases of posterior sternoclavicular joint (SCJ) dislocation have been documented in the medical literature since it was first described in 1824 by Sir Astley Cooper, a statistic which underlies its relative rarity. It is associated with high energy trauma, and although it may present innocently enough, it is a potentially life threatening injury.

Case and Results:We describe a case in which there was no clinical evidence of complication, although CT imaging revealed complete obstruction of the brachiocephalic vein and impingement of the aorta. This required open reduction and a novel fixation technique was employed. The reduction was stable at 8 month follow up appointment as evidenced by CT scan.

Conclusions:We acknowledge that this type of complication is well recognised but emphasise that it should not be managed complacently. A high index of suspicion is required to determine the presence of serious complications in this type of injury, which may manifest insidiously.
MANIFESTATION OF MIE RESONANCES IN COHERENT LIGHT BACKSCATTERING FROM RANDOM MEDIA
Authors: RANDALL SUMMER LOCKERBIE , BRODSKY ANATOL M. , BURGESS LLOYD W.
Published: April 2005

Utilization of Optical Low Coherence Reflectometry (OLCR) for measurement of coherent backscattering of light from media with randomly-distributed spherical particles shows the influence of Mie resonances over the parameter interval where particle radii are comparable to the wavelength of light. Results advance the understanding of the theoretically and practically important problem of wave propagation in multiscattering random media.
MAGNETOSTRICTIVE PROPERTIES OF TbDyFe ALLOYS ALONG THE DIRECTION PERPENDICULAR TO THE MAGNETIC FIELD
Authors: WANG ZHENGXING , FENG XUE , REN WENMIN , FANG DAINING
Published: April 2005

TbDyFe alloys play an important role in advanced actuator and sensor systems requiring either large displacement or large force, which may cause nonlinear response and performance degradation. In this investigation, experiments were performed to study the relevant magneto-mechanical response. The properties of magnetostriction along the direction perpendicular to the applied magnetic field were measured. The nonlinear behavior of the magnetostriction can be clearly explained in terms of domain rotating mechanism.
Distinct roles of nitric oxide synthases and interstitial cells of Cajal in rectoanal relaxation
Authors: Terauchi Akiko , Kobayashi Daisuke , Mashimo Hiroshi
Published: April 2005

Nitric oxide (NO) relaxes the internal anal sphincter (IAS), but its enzymatic source(s) remains unknown; neuronal (nNOS) and endothelial (eNOS) NO synthase (NOS) isoforms could be involved. Also, interstitial cells of Cajal (ICC) may be involved in IAS relaxation. We studied the relative roles of nNOS, eNOS, and c-Kit-expressing ICC for IAS relaxation using genetic murine models. The basal IAS tone and the rectoanal inhibitory reflex (RAIR) were assessed in vivo by a purpose-built solid-state manometric probe and by using wild-type, nNOS-deficient (nNOS−/−), eNOS-deficient (eNOS−/−), and W/Wvmice (lacking certain c-Kit-expressing ICC) with or without l-arginine or Nω-nitro-l-arginine methyl ester (l-NAME) treatment. Moreover, the basal tone and response to electrical field stimulation (EFS) were studied in organ bath using wild-type and mutant IAS. In vivo, the basal tone of eNOS−/−was higher and W/Wvwas lower than wild-type and nNOS−/−mice. l-Arginine administered rectally, but not intravenously, decreased the basal tone in wild-type, nNOS−/−, and W/Wvmice. However, neither l-arginine nor l-NAME affected basal tone in eNOS−/−mice. In vitro, l-arginine decreased basal tone in wild-type and nNOS−/−IAS but not in eNOS−/−or wild-type IAS without mucosa. The in vivo RAIR was intact in wild-type, eNOS−/−, and W/Wvmice but absent in all nNOS−/−mice. EFS-induced IAS relaxation was also reduced in nNOS−/−IAS. Thus the basal IAS tone is largely controlled by eNOS in the mucosa, whereas the RAIR is controlled by nNOS. c-Kit-expressing ICC may not be essential for the RAIR.
Glycine-extended gastrin stimulates cell proliferation and migration through a Rho- and ROCK-dependent pathway, not a Rac/Cdc42-dependent pathway
Authors: He Hong , Pannequin Julie , Tantiongco John-Paul , Shulkes Arthur , Baldwin Graham S.
Published: April 2005

Both amidated gastrin (Gamide) and glycine-extended gastrin (Ggly) stimulate gastrointestinal cell proliferation and migration. Binding of Gamide to the cholecystokinin-2 receptor activates small GTP-binding proteins of the Rho family (Rho, Rac, and Cdc42), and dominant-negative mutants of Rho or Cdc42 block Gamide-stimulated cell proliferation and survival. In comparison, little is known about the Ggly signaling transduction pathway leading to cell proliferation and migration. The present study examined the roles of the small G proteins Rho, Rac, and Cdc42 in Ggly-induced proliferation and migration of the mouse gastric epithelial cell line IMGE-5. Ggly stimulated the activation of Rho and its downstream effector protein ROCK. The activation of Rho and ROCK mediated Ggly-induced cell proliferation and migration as inhibition of Rho by C3, or ROCK by Y-27632, completely blocked these effects of Ggly. Ggly also stimulated tyrosine phosphorylation of focal adhesion kinase, and stimulation was reversed by addition of C3 and Y-27632. In contrast to the effects of Rho and ROCK, inhibition of the Rac or Cdc42 pathways by expression of dominant-negative mutants of Rac or Cdc42 did not affect Ggly-induced cell proliferation and migration. These results demonstrate that Ggly stimulates IMGE-5 cell proliferation and migration through a Rho/ROCK-dependent pathway but not via Rac- or Cdc42-dependent pathways.
Adrenergic catecholamine trophic activity contributes to flow-mediated arterial remodeling
Authors: Erami Cauveh , Zhang Hua , Tanoue Akito , Tsujimoto Gozoh , Thomas Steven A. , Faber James E.
Published: April 2005

Stimulation of α1-adrenoceptors (ARs) induces proliferation, hypertrophy, and migration of vascular smooth muscle cells and adventitial fibroblasts in cell and organ culture. In vivo studies have confirmed this direct trophic action and found that endogenous catecholamines contribute to neointimal formation and wall hypertrophy induced by mechanical injury. In murine carotid artery, these effects are mediated by α1B-ARs, whereas α1D-ARs mediate contraction and α1A-ARs are not expressed. Herein, we examined whether catecholamines also contribute to arterial wall growth in a noninjury model, i.e., flow-mediated remodeling. In wild-type mice or mice deficient in norepinephrine and epinephrine synthesis [dopamine β-hydroxylase knockout (DBH-KO)], all distal branches of the left carotid artery (LC) except the thyroid artery were ligated to reduce flow in the LC and increase flow in the right carotid artery (RC). Twenty-one days later, negative hypertrophic remodeling of the LC [i.e., −20% (decrease) in lumen area, −2% in circumference of the external elastic lamina (CEEL), +98% (increase) in thickness of the intima media, and +71% in thickness for adventitia; P < 0.01 vs. sham ligation] and positive eutrophic remodeling of the RC [+23% in lumen area, +11% in CEEL; P < 0.01 vs. sham ligation] were inhibited in DBH-KO mice [LC: +10% intima media and +3% adventitia; RC: +9% lumen area and +3% CEEL]. This inhibition was associated with reduced proliferation in the RC and reduced apoptosis and leukocyte accumulation in the RC and LC when examined 5 days after ligation. Carotid remodeling in α1D-AR-knockout mice evidenced little or no inhibition, which suggests dependence on α1B-ARs. These findings suggest that catecholamine-induced trophic activity contributes to both flow-mediated negative remodeling and adaptive positive arterial remodeling.
UT-B is expressed in bovine rumen: potential role in ruminal urea transport
Authors: Stewart G. S. , Graham C. , Cattell S. , Smith T. P. L. , Simmons N. L. , Smith C. P.
Published: April 2005

The UT-A ( SLC14a2) and UT-B ( SLC14a1) genes encode a family of specialized urea transporter proteins that regulate urea movement across plasma membranes. In this report, we describe the structure of the bovine UT-B (bUT-B) gene and characterize UT-B expression in bovine rumen. Northern analysis using a full-length bUT-B probe detected a 3.7-kb UT-B signal in rumen. RT-PCR of bovine mRNA revealed the presence of two UT-B splice variants, bUT-B1 and bUT-B2, with bUT-B2 the predominant variant in rumen. Immunoblotting studies of bovine rumen tissue, using an antibody targeted to the NH2-terminus of mouse UT-B, confirmed the presence of 43- to 54-kDa UT-B proteins. Immunolocalization studies showed that UT-B was mainly located on cell plasma membranes in epithelial layers of the bovine rumen. Ussing chamber measurements of ruminal transepithelial transport of 14C-labeled urea indicated that urea flux was characteristically inhibited by phloretin. We conclude that bUT-B is expressed in the bovine rumen and may function to transport urea into the rumen as part of the ruminant urea nitrogen salvaging process.
Effect of water deprivation on cognitive-motor performance in healthy men and women
Authors: Szinnai Gabor , Schachinger Hartmut , Arnaud Maurice J , Linder Lilly , Keller Ulrich
Published: April 2005

Whether mental performance is affected by slowly progressive moderate dehydration induced by water deprivation has not been examined previously. Therefore, objective and subjective cognitive-motor function was examined in 16 volunteers (8 females, 8 males, mean age: 26 yr) twice, once after 24 h of water deprivation and once during normal water intake (randomized cross-over design; 7-day interval). Water deprivation resulted in a 2.6% decrease in body weight. Neither cognitive-motor function estimated by a paced auditory serial addition task, an adaptive 5-choice reaction time test, a manual tracking test, and a Stroop word-color conflict test nor neurophysiological function assessed by auditory event-related potentials P300 (oddball paradigm) differed ( P > 0.1) between the water deprivation and the control study. However, subjective ratings of mental performance changed significantly toward increased tiredness (+1.0 points) and reduced alertness (−0.9 points on a 5-point scale; both: P < 0.05), and higher levels of perceived effort (+27 mm) and concentration (+28 mm on a 100-mm scale; both: P < 0.05) necessary for test accomplishment during dehydration. Several reaction time-based responses revealed significant interactions between gender and dehydration, with prolonged reaction time in women but shortened in men after water deprivation (Stroop word-color conflict test, reaction time in women: +26 ms, in men: −36 ms, P < 0.01; paced auditory serial addition task, reaction time in women +58 ms, in men −31 ms, P = 0.05). In conclusion, cognitive-motor function is preserved during water deprivation in young humans up to a moderate dehydration level of 2.6% of body weight. Sexual dimorphism for reaction time-based performance is present. Increased subjective task-related effort suggests that healthy volunteers exhibit cognitive compensating mechanisms for increased tiredness and reduced alertness during slowly progressive moderate dehydration.
The Effect of the Emotion of Happiness on Allergic Skin Wheal Responses and Plasma Levels of Neuropeptides and Nerve Growth Factor in Patients with Allergic Rhinitis
Authors: Kimata Hajime
Published: April 2005

Objectives: The effect of the emotion of happiness on allergic responses and plasma levels of neuropeptides and neurotrophins was studied in patients with allergic rhinitis. Patients and Methods: 27 patients with allergic rhinitis and 27 normal subjects who passed the entrance examination to university were studied. One day before, 1 h before and soon after the announcement of the results of the entrance examination, skin prick tests by Japanese cedar pollen, house dust mite and histamine were performed, and simultaneously plasma levels of substance P (SP), vasoactive intestinal peptide (VIP), nerve growth factor (NGF) and neurotrophin 3 (NT-3) were measured. Results and Conclusion: Happiness induced by passing the entrance examination to university reduced skin wheal responses induced by Japanese cedar pollen and house dust mite, while it had no effect on skin wheal responses induced by histamine in patients with allergic rhinitis. Happiness also reduced the plasma levels of SP, VIP and NGF, but not NT-3, in patients with allergic rhinitis. In contrast, happiness had no effect on skin wheal responses induced by histamine or plasma levels of SP; VIP, NGF or NT-3 in normal subjects. These results indicate that happiness may reduce allergen-induced wheal responses in association with a decrease in SP, VIP and NGF but not NT-3. This finding may be useful in elucidating the neuroimmunology and treatment of allergic rhinitis.
Dysphonia in the Elderly: A Comparison of Benign Etiologies of Hoarseness in Two Different Cultures
Authors: Kandogan T. , Seifert E.
Published: April 2005

Objective: The objective of this study was to review the benign causes of hoarseness in the elderly above 60 years of age and to compare them between the two different cultures of Switzerland and Turkey. Material and Method: 140 patients were enrolled in the study, 69 (37 males, 32 females; mean age 66 years) from Berne, Switzerland, and 71 (41 males, 30 females; mean age 63 years) from Izmir, Turkey. Results and Conclusions: In the Berne study group, the most common benign causes of hoarseness registered in the elderly above 60 years of age were vocal cord paralysis (n = 31; 45%) and functional dysphonia (n = 24; 35%). These were followed by benign vocal cord lesions such as Reinke edema, contact granuloma or laryngeal papilloma (n = 4; 6%) and presbyphonia (n = 4; 6%). Laryngopharyngeal reflux was found in 8 patients (12%), 7 of them with functional dysphonia. In the Izmir study group, the most common benign causes of hoarseness detected in the elderly were vocal cord lesions (n = 28; 39%) and vocal cord paralysis (n = 25; 35%). These were followed by functional dysphonia (n = 10; 14%) and presbyphonia (n = 8; 11%). Seven patients (10%) in the Izmir study group were suffering from laryngopharyngeal reflux; this was combined with benign vocal cord lesions or functional dysphonia. The high percentage of patients with vocal cord paralysis is presumed to be due to the consultation having taken place at a tertiary-care center. However, there is a notable difference in the etiologies of vocal cord paralysis between the two compared groups: the paralysis in the Berne group was caused by diagnostic or therapeutic procedures relating to bronchopulmonary malignancies, whereas it was caused by the disease itself in the Izmir group. Organic manifestations of vocal misuse and poor voice hygiene were more frequent in the Izmir group. It may be supposed that the patients in the Swiss group were more careful with their voices and/or consulted their ENT specialists on functional voice disorders before organic lesions developed.
Cost-Effectiveness of the Histopathologic Assessment of Tonsillectomy Material
Authors: Aydin Abdullah , Erkiliç Suna , Bayazit Yildirim A. , Koçer N. Emrah , Kanlikama Muzaffer , Özer Enver , Mumbuç Semih
Published: April 2005

Objective: To find out the significance of the histopathologic assessment of tonsillectomy materials in an attempt to understand the cost-effectiveness of this procedure. Patients and Methods: Hematoxylin- and eosin-stained sections of 1,820 tonsillectomy samples were re-evaluated, and clinical charts of the patients were made. Results: There was Actinomyces in 122 (6.7%), cryptic abscess in 144 (7.9%), cyst formation in 146 (8.0%) and granuloma in 11 (0.6%). Malignancy was found in 9 (0.5%) of 1,820 patients. In these patients with histopathologically confirmed malignancy, tonsillectomy had been performed with a presumptive diagnosis of malignant disease. Conclusions: Routine histopathologic examination of tonsillectomy material is not necessary unless there is a strong suspicion of malignancy on clinical evaluation. Thus, the cost of hospital expenses can be decreased to some extent. This will also eliminate the waste of time due to histopathologic assessment unless residency training is the subject of discussion. The medical-legal limitations should also be taken into consideration while making decisions about the necessity of histopathologic examination of these specimens.
The Role of Fine-Needle Aspiration Biopsy in the Evaluation of Head and Neck Masses
Authors: Kutluhan Ahmet , Kisli Erol , Yakut Fatih , Yurttaş Veysel , Kösem Mustafa
Published: April 2005

Purpose: The purpose of this study is to evaluate the role of diagnostic fine-needle aspiration biopsy (FNAB) of head and neck masses and to calculate the sensitivity and specificity of this method. Materials and Methods: The records of 219 patients who had undergone an FNAB of head or neck masses were reviewed. FNAB results were correlated with the histopathologic findings observed after surgery in 96 of 219 patients. Sensitivity, specificity and positive predictive value of FNAB for the detection of malignancy were calculated. Results: Four false-negative, 4 false-positive and 22 unsatisfactory results were obtained using FNAB, according to histopathologic findings. The overall sensitivity, specificity, accuracy and positive predictive value for malignancy were 87.5, 93.8, 91 and 87.5%, respectively. Conclusions: FNAB is a useful diagnostic tool for head and neck masses. However, FNAB results by themselves could be insufficient in the management of head and neck masses; therefore, they should be combined with clinical and radiologic findings.
Acoustic Neuroma: An Exploration of Patients’ Beliefs
Authors: Grunfeld E.A. , Sandooram D. , Gleeson M.
Published: April 2005

Objectives: Identification of patients’ beliefs about their illness is important as these beliefs can shape subsequent emotional responses and coping behaviours. This study examined acoustic neuroma patients’ illness representations using a health psychology model as the basis for the question development. Patients: One hundred and sixty-five patients who had undergone treatment/management at a London teaching hospital between 1985 and 2001. Methods: Participants completed a series of 6 open-end questions, which were mailed as part of a larger questionnaire study. The open questions elicited a wide range of responses. Results and Conclusions: The main symptoms experienced by patients prior to treatment were hearing loss (68% of respondents), balance difficulties (53%) and tinnitus (34%). The consequences of hearing loss, such as conversational difficulties, were the greatest concern of patients, although changes in social and work activities were also highlighted. The results of the study improve our understanding of the symptoms, concerns and beliefs that acoustic neuroma patients may hold prior to treatment. In addition, the results highlight concerns and misconceptions among patients that may need to be addressed through the provision of appropriate information.
The Impact of a Partial Glossectomy on Articulation and Speech Intelligibility
Authors: van Lierde Kristiane M. , Vermeersch Hubert , van Borsel John , van Cauwenberge Paul
Published: April 2005

Objectives: The purpose was to determine the changes in intelligibility and articulation after partial glossectomy in a child with Beckwith-Wiedemann syndrome. Methods: For the assessment of articulation, a speech sample was gathered by means of a picture naming test. The analyses included a description of the child’s sound production regardless of their relation to the adult target, as well as analyses comparing the patient’s pronunciations with the adult form. For the assessment of intelligibility the sample was independently rated by 2 experienced speech pathologists using a nominal scale with four categories. Results and Conclusions: Partial glossectomy resulted in a dramatic improvement of speech. Before surgery the speech was definitely not age-appropriate. The child was capable of producing only 23% of the Dutch consonants. This is far less than expected at that age. After surgery, consonant inventory was almost complete and as such was even more than age-appropriate. The partial glossectomy had obviously a positive impact on both place of articulation and manner of articulation. The analyses revealed a tendency towards vowel speech before surgery along with glottal realizations. After surgery the vowel speech and the compensatory articulation patterns had disappeared. Several factors that contributed to the improvement are discussed.
Late Detection of Hearing Loss in a Case with Middle Ear Congenital Abnormality
Authors: Tzangaroulakis A. , Korres S. , Alatzidou Z. , Maragoudakis P. , Ferekidis E.
Published: April 2005

The present paper describes a rare case of a unilateral congenital ossicular abnormality that presented in adulthood. A unilateral conductive hearing loss was revealed during a routine examination for a professional driving license. Differential diagnosis included otosclerosis and ossicular anomalies. Our patient, a 40-year-old man, had no history of otitis media or trauma to the head and he was not aware of his hearing loss. Exploratory tympanotomy revealed absence of the long process of the incus and of the stapes. A remnant of the underdeveloped stapes footplate was removed and reconstruction of the defect using a 5.0-mm malleus-oval window prosthesis had an excellent result with complete restoration of the air-bone gap. The patient experienced binaural hearing with great excitement.