bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of the Otoliths in Perception of the Vertical and in Path Integration
Authors: MITTELSTAEDT HORST 
Published: February 2006

Abstract: The role of the otoliths in essential performances of human orientation is analyzed. The following interactions of the otoliths are considered:1. The otoliths cooperate with graviceptors in the trunk in the perception of body posture. The truncal graviceptors turn out to yield on average 60% of the total gain.2. The otoliths cooperate with proprioceptors in the head‐to‐trunk coordinate transformation. However, under static conditions, proprioceptors in the legs, although effective in the control of posture, neither affect the perception of posture nor of the visual vertical.3. In contrast to the perception of posture, the perception of the visual vertical (SVV) receives the necessary gravity information exclusively from the otoliths. However, their output appears to be affected by a central nervous component that tends to rotate the SVV into the z‐axis of head and trunk. A theory of vectorial summation of this component, the “idiotropic vector,” with the otolithic vector is able to explain the cause of the A‐ and E‐ effects, the increase of the variance of the SVV with the tilt angle, and the asymmetrical effect of rotatory visual flow.4. Finally, it is shown that the otoliths, by the separation of the effects of tilt from those of translation, play an essential role in navigation by path integration.
Mesolimbic Activity Associated with Psychosis in Schizophrenia: Symptom‐specific PET Studies
Authors: EPSTEIN JANE , STERN EMILY , SILBERSWEIG DAVID 
Published: February 2006

ABSTRACT: Hallucinations and paranoid delusions are prominent among the positive symptoms of schizophrenia. Such psychotic symptoms are notable for their aberrant representations of, and relation to, the external world and for the emotional/motivational valence associated with the representations. As mesolimbic structures, including the amygdala and ventral striatum, are thought to play a significant role in imparting emotional valence to external stimuli, we here examine the mesolimbic findings of H215O PET studies designed to probe the functional neuroanatomy of psychosis.Patients with schizophrenia (including those with active hallucinations, those with active paranoid delusions, and those without active positive symptoms at the time of scanning) and healthy control subjects were studied. An event‐related PET paradigm was used to identify the neural correlates of hallucinations, and a modified emotional stroop paradigm (with threat versus neutral words) was used to test the hypothesis that paranoid patients would have increased mesolimbic activity in response to threat, and even in response to neutral stimuli.The findings suggest that the positive psychotic symptoms of hallucinations and delusions share similar functional neuroanatomical features of increased mesotemporal and ventral striatal activity in the setting of decreased prefrontal activity. The pattern is evident even in a neutral context, unlike the case for normal subjects, who show such features only in response to threat. The implications of these findings for a pathophysiology of psychosis will be discussed in the context of the behavioral neuroanatomical literature in animals and humans.
The Novel Trk Receptor Tyrosine Kinase Inhibitor CEP‐701 (KT‐5555) Exhibits Antitumor Efficacy against Human Pancreatic Carcinoma (Panc1) Xenograft Growth and In Vivo Invasiveness
Authors: MIKNYOCZKI SHEILA J. , DIONNE CRAIG A. , KLEIN‐SZANTO ANDRES J.P. , RUGGERI BRUCE A. 
Published: February 2006

Abstract: The survival rate for patients with pancreatic ductal adenocarcinoma (PDAC) is among the poorest for all cancers. The factors that contribute to this poor prognosis are lack of effective early detection, high rate of metastases and a generally refractory response to available treatment modalities.The most commonly used treatment methods‐chemotherapy and radiation therapy‐are mainly used for symptom palliation, with surgery being the only “curative” treatment option. The use of combinations of treatment modalities is the only therapy available to patients with locally advanced disease or that which is surgically unresectable. These options are still not sufficient to increase patient survival time significantly.The aggressive behavior and poor prognosis of this cancer is associated with an increased expression of many growth factors and their cognate receptors. We have demonstrated previously the aberrant expression of the Trk receptors (Trks A, B, and C) in PDAC specimens and human PDAC‐derived cell lines and a biphasic, dose‐dependent response of specific neurotrophic agents on the in vitro invasiveness of PDAC cells. Based on these data we have evaluated the therapeutic potential of inhibiting neurotrophin‐Trk interactions using a selective Trk tyrosine kinase inhibitor (CEP‐701) on subcutaneous (s.c.) and tracheal xenografts derived from the poorly differentiated PDAC cell line, Panc1.We demonstrate that CEP‐701 administration at 10 mg/kg s.c. BID for 21 days inhibited tumor growth of the Panc1 s.c. xenografts in a statistically‐significant manner (p <0.01) compared to vehicle controls, in the absence of morbidity and mortality. A T/C value of 25% was observed for CEP‐701‐treated s.c. xenografts. In addition, CEP‐701 administration inhibited tumor cell invasion in the s.c. tracheal xenograft model of in vivo invasiveness. Taken together, these data suggest that further studies are warranted to evaluate CEP‐701 as a potential therapeutic agent in the treatment of PDAC.
Eugenol-induced contractions of saponin-skinned fibers are inhibited by heparin or by a ryanodine receptor blocker
Authors: Lofrano-Alves Marco S. , Oliveira Edson L. , Damiani Carlos E.N. , Kassouf-Silva Ilana , Fogaça Rosalvo T.H. 
Published: February 2006

The effects of eugenol on the sarcoplasmic reticulum (SR) and contractile apparatus of chemically skinned skeletal muscle fibers of the frog Rana catesbeiana were investigated. In saponin-skinned fibers, eugenol (5 mmol/L) induced muscle contractions, probably by releasing Ca2+from the SR. The Ca2+-induced Ca2+release blocker ruthenium red (10 μmol/L) inhibited both caffeine- and eugenol-induced muscle contractions. Ryanodine (200 μmol/L), a specific ryanodine receptor/Ca2+release channel blocker, promoted complete inhibition of the contractions induced by caffeine, but only partially blocked the contractions induced by eugenol. Heparin (2.5 mg/mL), an inositol 1,4,5-trisphosphate (InsP3) receptor blocker, strongly inhibited the contractions induced by eugenol but had only a small effect on the caffeine-induced contractions. Eugenol neither altered the Ca2+sensitivity nor the maximal force in Triton X-100 skinned muscle fibers. These data suggest that muscle contraction induced by eugenol involves at least 2 mechanisms of Ca2+release from the SR: one related to the activation of the ryanodine receptors and another through a heparin-sensitive pathway.
Régulation de la volémie au cours d’une simulation d’impesanteur de longue durée
Authors: Custaud Marc-Antoine , Belin de Chantemèle Éric , Blanc Stéphane , Gauquelin-Koch Guillemette , Gharib Claude 
Published: February 2006

Pour étudier les effets de la microgravité sur les mécanismes de régulation de la volémie et de l’eau corporelle totale (ECT), les variations d’ECT, du volume plasmatique (VP) et des principales hormones intervenant dans la régulation de la volémie (rénine, aldostérone, peptide atrial natriurétique (ANP), hormone anti-diurétique (ADH)) ont été déterminées par dilution isotopique, formule de Dill et Costill et dosages radio-immunologiques, chez 9 hommes soumis à un alitement à –6° de 3 mois. Les osmolalités urinaires et plasmatiques, la natrémie, la kaliémie et les excrétions urinaires sodée et potassique ont aussi été mesurées. Pendant ces 3 mois, la masse des sujets (–2,8 ± 0,8 kg), l’eau totale (–7,2 % ± 0,9 % soit –2,6 ± 0,7 kg) et le VP (–4,7 % ± 1,8 %) ont diminué. La rénine plasmatique et l’aldostérone ont augmenté (+109,0 % ± 15,4 % et +87,2 % ± 38,9 % respectivement). L’ANP a diminué de –33,2 % ± 20,4 %. Les autres variables, dont l’ADH, n’ont pas changé. La baisse pondérale, la diminution de l’ECT et de la masse maigre s’expliquent vraisemblablement par une atrophie musculaire. L’élévation des facteurs de rétention sodée et l’inhibition de l’ANP s’expliquent par l’hypovolémie modérée, qui, sans variation de l’osmolalité plasmatique, semble incapable de stimuler la sécrétion d’ADH. Ce dernier fait démontre la primauté de l’osmolalité plasmatique dans la régulation de l’ADH.
The α1-adrenergic receptor not the DA1-dopaminergic receptor mediates cyclosporine–SKF38393 renovascular interaction
Authors: El-Mas Mahmoud M. , El-Din Mahmoud M. Mohy , El-gowilly Sahar M. , Sharabi Fouad M. 
Published: February 2006

In this study, we investigated the effect of acute exposure to cyclosporine A (CyA) on renal vasodilations evoked by the DA1 dopaminergic agonist SKF38393 and whether dopamine DA1 receptors are directly involved in the interaction. Changes evoked by CyA in SKF38393 vasodilations were evaluated in phenylephrine-preconstricted isolated perfused rat kidneys in the absence and presence of SCH23390, a DA1 receptor antagonist. SKF38393 (3 × 10–8 to 3 × 10–6 mol) produced dose-dependent reductions in the renal perfusion pressure that were significantly attenuated in tissues pretreated with SCH23390 or CyA. Unlike SKF38393, the vasodilatory action of sodium nitroprusside, a nitrovasodilator, was not altered by CyA. The attenuating effect of CyA on SKF38393 vasodilations was preserved in preparations pretreated with SCH23390, suggesting that sites other than DA1 receptors may be involved in CyA–SKF38393 interaction. The study was then extended to investigate the possible involvement of renal α1-adrenoceptors in the interaction. Blockade of α1-adrenoceptors by prazosin (30 nmol/L) significantly reduced the vasodilatory effect of SKF38393 and virtually abolished the CyA-induced attenuation of SKF38393 responses. Further, CyA failed to alter SKF38393 vasodilations when the renal tone was raised with prostaglandin F2α (PGF2α), a vasoconstrictor whose effect is independent of α1-adenoceptors. Together, these findings support earlier reports that both DA1 and α1-receptors mediate the renal vasodilatory action of SKF38393 and suggest that CyA interacts selectively with the α1-receptor component to compromise SKF38393 responses.
Glyceryl trinitrate-induced angiotensin-converting enzyme (ACE) inhibition in healthy volunteers is dependent on ACE genotype
Authors: Persson Karin , Säfholm Annette C.E. , Andersson Rolf G.G. , Ahlner Johan 
Published: February 2006

Evidence concerning the importance of angiotensin-converting enzyme (ACE) genotype in cardiovascular diseases is accumulating. The aim of this study was to investigate if nitric oxide (NO), generated from glyceryl trinitrate (GTN), affects human serum ACE activity in vivo, and if so, whether this effect was dependent on ACE genotype and (or) reflected in blood pressure reduction. A tablet containing 5 mg GTN was bucally administered for 5 minutes to 17 healthy volunteers. Blood pressure (BP) was recorded, and serum ACE activity, ACE genotype, and plasma cGMP was analyzed. GTN administration significantly reduced BP only in individuals with the deletion/deletion (DD) genotype. Sixty minutes after GTN administration, serum ACE activity was reduced in individuals with the insertion/insertion (II) and insertion/deletion (ID) genotypes, but not the DD genotype. Comparing the change in ACE activity over time between the genotypes resulted in the following: II vs. DD, p < 0.01; II vs. ID, p < 0.05; and ID vs. DD, p < 0.05. There was no significant difference in plasma cGMP content neither between the ACE genotypes nor before and after GTN administration. In conclusion, GTN inhibits serum ACE in vivo in individuals with the II and ID, but not the DD genotype.
NOVEL SOUND PHENOMENA IN IMPURE SUPERFLUIDS
Authors: BRUSOV PETER , BRUSOV PAVEL 
Published: February 2006

In the last decade, new techniques for producing impure superfluids with unique properties have been developed. This new class of systems includes superfluid helium confined to aerogel, HeII with different impurities, superfluids in Vycor glasses, and watergel. These systems exhibit very unusual properties including unexpected acoustic features. We discuss the sound properties of these systems and show that sound phenomena in impure superfluids are modified from those in pure superfluids. We calculate the coupling between temperature and pressure oscillations for impure superfluids and show that this coupling increases significantly. This leads to the existence in impure superfluids of such unusual sound phenomena as slow "pressure" waves and fast "temperature" waves. This also decreases the threshold values for nonlinear processes as compared to pure superfluids. Sound conversion, which has been observed in pure superfluids only by high intensity waves should be observed at moderate sound amplitude in impure superfluids. Cerenkov emission of second sound by first sound (which has never been observed in superfluids) could be observed in impure superfluids. Even the nature of the sound modes in impure superfluids turns out to be changed. We have also derived for the first time the nonlinear hydrodynamic equations for superfluid helium in aerogel.
REMARKS ON SKEW PRODUCTS OVER IRRATIONAL ROTATIONS
Authors: LERMAN L. M. 
Published: February 2006

We prove several results of the orbit behavior of skew product diffeomorphisms generated by quasi-periodic differential systems. The first diffeomorphism is derived from a periodic differential equation on the circle by means of a construction proposed by Z. Opial to get a scalar quasi-periodic equation with all its solutions bounded but without an almost periodic solution. We consider both possible cases for the irrational rotation number, transitive and singular (intransitive). The main result for a transitive case is that the related skew product diffeomorphism has a foliation into invariant curves with pure irrational rotation on each curve (being the same for each curve). For intransitive case, we get invariant sets of two types: a collection of continuous invariant curves and invariant sets being dimensionally inhomogeneous ones.Section 3 is devoted to perturbations of a skew product diffeomorphism over an irrational rotation being initially foliated into invariant curves. We prove an analog of Poincaré–Pontryagin theorem which sets conditions when a perturbation of a one-degree-of-freedom Hamiltonian system (given in an annulus and written down in action-angle variables) has limit cycles. Our theorem provides sufficient conditions when a perturbation of a foliated skew product diffeomorphism has isolated invariant curves (asymptotically stable or unstable).In Sec. 4 we present some results on the geometry of skew product diffeomorphisms derived by a quasi-periodic Riccati equation.
ROOTS AND CENTRALIZERS OF ANOSOV DIFFEOMORPHISMS ON TORI
Authors: FIEDLER BERNOLD 
Published: February 2006

The centralizer of a group element g is the group of elements commuting with g. Powers and, if existent, roots of g are contained in the centralizer. We call a centralizer trivial if it consists of the integer powers of g, only. In the group of torus homeomorphisms, we study the centralizer of torus diffeomorphisms of hyperbolic Anosov type. As a result, the centralizer can be calculated, isomorphically, in the much smaller group of affine torus automorphisms. In particular, Anosov diffeomorphisms of the 2-torus with a unique fixed point possess trivial centralizer, up to a trivial involution. The identification of individual reactors from data on reactor cascades, for example in chemical engineering, is one source of motivation for the study of roots of diffeomorphisms. Another possible source is the study of commuting diffeomorphisms in finite-dimensional spatially or spatio-temporally chaotic systems.
To consolidate or distribute?
Authors: Johnk Linn , Manahan Meera , Graefe Tom 
Published: February 2006

In large companies, the processes of user-centered design (UCD)---or as these authors say, "customer-centered design (CCD)"---may be similar across business units, but the content of the work may differ dramatically from one unit to another. Thus, like many other "minority" professions, User Experience and UCD communities struggle with how to balance full involvement in and service to their business units with coordination, professional cohesion, and leadership across business units. In this month's column, our authors discuss how they and their colleagues at Hewlett Packard have been working to strengthen their professional community across the company, while preserving the ties linking practitioners and their business units.
---Susan Dray and David Siegel
The Metabolic Syndrome Is Associated with Reduced Central Serotonergic Responsivity in Healthy Community Volunteers
Authors: Muldoon Matthew F. , Mackey Rachel H. , Korytkowski Mary T. , Flory Janine D. , Pollock Bruce G. , Manuck Stephen B. 
Published: February 2006

Context: The pathobiology of the metabolic syndrome remains unclear. The central nervous system is likely to be involved via regulation of eating, physical activity, blood pressure, and metabolism.
Objective: The objective of this study was to test the hypothesis that low central serotonergic activity is associated with the metabolic syndrome.
Design, Setting, Participants: This was a cross-sectional study of 345 healthy community volunteers, aged 30–55 yr, not taking medications for hypertension, lipid disorders, or diabetes.
Outcome Measures: Central serotonergic responsivity was assessed with the iv citalopram challenge test. The serum prolactin area under the curve (AUC) over 150 min was calculated, and all analyses were adjusted for age, sex, plasma citalopram concentration, and baseline prolactin. The metabolic syndrome was defined according to the National Cholesterol Education Program (NCEP) and International Diabetes Federation (IDF) criteria. Insulin resistance was estimated by homeostasis model assessment.
Results: Compared with other individuals, persons meeting either NCEP or IDF criteria for the metabolic syndrome had lower mean prolactin responses (P &lt; 0.05 for both). Using logistic regression, a decrease in prolactin AUC of 1 sd (−13.6 ng/ml·h) more than doubled the odds of having the metabolic syndrome (NCEP criteria: odds ratio, 2.38; 95% confidence interval, 1.14–4.97; P = 0.02; IDF criteria: odds ratio, 2.80; 95% confidence interval, 1.48–5.30; P = 0.002). Finally, the prolactin AUC was negatively associated with insulin resistance (β = −0.03, P = 0.02).
Conclusions: Corroborating previous evidence, the metabolic syndrome was associated with diminished brain serotonergic activity as reflected in a comparative blunting of the prolactin response to a selective serotonergic challenge. This association may have implications for the etiology, prevention, and treatment of the metabolic syndrome.
Low Serum Thyrotropin Is Associated with High Plasma Fibrinogen
Authors: Dörr Marcus , Robinson Daniel M. , Wallaschofski Henri , Schwahn Christian , John Ulrich , Felix Stephan B. , Völzke Henry 
Published: February 2006

Background: Elevated plasma fibrinogen levels are associated with an increased risk of cardiovascular events. Decreased serum TSH predicts vascular mortality, which hypothetically could be explained in part by alterations in the blood coagulation system.
Objective: The objective of this study was to investigate the association between thyroid function and plasma fibrinogen levels in a general population.
Design: The population-based Study of Health in Pomerania was performed in a previously iodine-deficient area in Germany, including 4310 subjects, aged 20–79 yr. Data for 3804 individuals without thyroid disease were analyzed. Analysis revealed an association between thyroid function status and plasma fibrinogen concentration.
Results: Elevated fibrinogen levels (&gt;3.25 g/liter) were observed in 14 subjects with increased serum TSH levels (32.6%), 973 euthyroid subjects (28.9%), 158 subjects with decreased serum TSH levels (40.7%), and six individuals with overt hyperthyroidism (54.4%). Logistic regression analysis revealed decreased serum TSH as an independent risk factor for elevated fibrinogen levels (odds ratio, 1.42; 95% confidence interval, 1.12–1.80).
Conclusions: Thyroid function is associated with plasma fibrinogen. Decreased serum TSH is an independent risk factor for elevated plasma fibrinogen levels as a possible explanation for the high cardiovascular mortality among affected subjects.
Insulin Resistance in Human Preeclamptic Placenta Is Mediated by Serine Phosphorylation of Insulin Receptor Substrate-1 and -2
Authors: Scioscia Marco , Gumaa Khalid , Kunjara Sirilaksana , Paine Malcolm A. , Selvaggi Luigi E. , Rodeck Charles H. , Rademacher Thomas W. 
Published: February 2006

Context: Preeclampsia is a severe complication of human pregnancy often associated with maternal risk factors. Insulin resistance represents a major risk for developing preeclampsia during pregnancy.
Objective: A putative second messenger of insulin, inositol phosphoglycan P type (P-IPG), was previously shown to be highly increased during active preeclampsia. Its association with insulin resistance was investigated.
Design and Setting: A cross-sectional study was carried out in a referral center.
Patients: Nine preeclamptic (PE) and 18 healthy women were recruited and matched for maternal age, body mass index, parity, and ethnicity in a 1:2 ratio. Placental specimens were collected immediately after delivery.
Intervention: Placental tissue was incubated with insulin and P-IPG production assessed. Insulin signaling proteins were subsequently studied by immunoblotting.
Results: P-IPG extracted from human term placentas upon incubation with insulin was found to be far lower in those with preeclampsia than controls (P &lt; 0.001). Immunoblotting studies revealed serine phosphorylation of insulin receptor substrate-1 and -2 in PE placentas (P &lt; 0.001) with downstream impairment of insulin signaling. The activation of the p85 regulatory subunit of phosphatidylinositol 3- kinase was markedly decreased in PE samples (P &lt; 0.001).
Conclusions: These findings highlight the importance of P-IPG in active preeclampsia and demonstrate a substantially different response to the insulin stimulus of human PE placentas. Acquired alterations in activation of proteins involved in insulin signaling may play a role in the complex pathogenesis of preeclampsia, probably as a consequence of the immunological dysfunction that occurs in this syndrome. These results seem to confirm an insulin-resistant state in PE placenta and shed a different light on its role in the pathogenesis of this disease with potential therapeutic implications.