bluuebunny/crossref_metadata_2025 huggingface dataset:
SCAR/WAVE and Arp2/3 are crucial for cytoskeletal remodeling at the site of myoblast fusion
Authors: Richardson Brian E. , Beckett Karen , Nowak Scott J. , Baylies Mary K.
Published: November 2007

Myoblast fusion is crucial for formation and repair of skeletal muscle. Here we show that active remodeling of the actin cytoskeleton is essential for fusion in Drosophila. Using live imaging, we have identified a dynamic F-actin accumulation (actin focus) at the site of fusion. Dissolution of the actin focus directly precedes a fusion event. Whereas several known fusion components regulate these actin foci, others target additional behaviors required for fusion. Mutations in kette/Nap1, an actin polymerization regulator, lead to enlarged foci that do not dissolve,consistent with the observed block in fusion. Kette is required to positively regulate SCAR/WAVE, which in turn activates the Arp2/3 complex. Mutants in SCAR and Arp2/3 have a fusion block and foci phenotype,suggesting that Kette-SCAR-Arp2/3 participate in an actin polymerization event required for focus dissolution. Our data identify a new paradigm for understanding the mechanisms underlying fusion in myoblasts and other tissues.
Cytoplasmic domain requirements for Frazzled-mediated attractive axon turning at theDrosophilamidline
Authors: Garbe David S. , O'Donnell Mike , Bashaw Greg J.
Published: November 2007

The conserved DCC ligand-receptor pair Netrin and Frazzled (Fra) has a well-established role in axon guidance. However, the specific sequence motifs required for orchestrating downstream signaling events are not well understood. Evidence from vertebrates suggests that P3 is important for transducing Netrin-mediated turning and outgrowth, whereas in C. elegans it was shown that the P1 and P2 conserved sequence motifs are required for a gain-of-function outgrowth response. Here, we demonstrate that Drosophila fra mutant embryos exhibit guidance defects in a specific subset of commissural axons and these defects can be rescued cell-autonomously by expressing wild-type Fra exclusively in these neurons. Furthermore,structure-function studies indicate that the conserved P3 motif (but not P1 or P2) is required for growth cone attraction at the Drosophila midline. Surprisingly, in contrast to vertebrate DCC, P3 does not mediate receptor self-association, and self-association is not sufficient to promote Fra-dependent attraction. We also show that in contrast to previous findings,the cytoplasmic domain of Fra is not required for axonal localization and that neuronal expression of a truncated Fra receptor lacking the entire cytoplasmic domain (FraΔC) results in dose-dependent defects in commissural axon guidance. These findings represent the first systematic dissection of the cytoplasmic domains required for Fra-mediated axon attraction in the context of full-length receptors in an intact organism and provide important insights into attractive axon guidance at the midline.
NBS1 mediates ATR-dependent RPA hyperphosphorylation following replication-fork stall and collapse
Authors: Manthey Karoline C. , Opiyo Stephen , Glanzer Jason G. , Dimitrova Diana , Elliott James , Oakley Gregory G.
Published: November 2007

Post-translational phosphorylation of proteins provides a mechanism for cells to switch on or off many diverse processes, including responses to replication stress. Replication-stress-induced phosphorylation enables the rapid activation of numerous proteins involved in DNA replication, DNA repair and cell cycle checkpoints, including replication protein A (RPA). Here, we report that hydroxyurea (HU)-induced RPA phosphorylation requires both NBS1 (NBN) and NBS1 phosphorylation. Transfection of both phosphospecific and nonphosphospecific anti-NBS1 antibodies blocked hyperphosphorylation of RPA in HeLa cells. Nijmegen breakage syndrome (NBS) cells stably transfected with an empty vector or with S343A-NBS1 or S278A/S343A phospho-mutants were unable to hyperphosphorylate RPA in DNA-damage-associated foci following HU treatment. The stable transfection of fully functional NBS1 in NBS cells restored RPA hyperphosphorylation. Retention of ATR on chromatin in both NBS cells and in NBS cells expressing S278A/S343A NBS1 mutants decreased after DNA damage, suggesting that ATR is the kinase responsible for RPA phosphorylation. The importance of RPA hyperphosphorylation is demonstrated by the ability of cells expressing a phospho-mutant form of RPA32 (RPA2) to suppress and delay HU-induced apoptosis. Our findings suggest that RPA hyperphosphorylation requires NBS1 and is important for the cellular response to DNA damage.
Rip11 is a Rab11- and AS160-RabGAP-binding protein required for insulin-stimulated glucose uptake in adipocytes
Authors: Welsh Gavin I. , Leney Sophie E. , Lloyd-Lewis Bethan , Wherlock Matthew , Lindsay Andrew J. , McCaffrey Mary W. , Tavaré Jeremy M.
Published: November 2007

The translocation of GLUT4 to the plasma membrane underlies the ability of insulin to stimulate glucose uptake, an event that involves the activation of protein kinase B, several members of the Rab family of GTP-binding proteins and the phosphorylation of the Rab GTPase-activating protein AS160. Here, we explored the regulation by insulin of the class I Rab11-interacting proteins Rip11, RCP and FIP2. We show that Rip11, but not RCP or FIP2, translocates to the plasma membrane of 3T3-L1 adipocytes in response to insulin. This unique response of Rip11 prompted us to explore the role of this protein in more detail. We found that Rip11 partially colocalises with GLUT4 in intracellular compartments. siRNA-mediated knockdown of Rip11 inhibits insulin-stimulated uptake of 2-deoxyglucose, and overexpression of Rip11 blocks insulin-stimulated insertion of translocated GLUT4 vesicles into the plasma membrane. We additionally show that Rip11 forms a complex with AS160 in a Rab11-independent manner and that insulin induces dissociation of AS160 from Rip11. We propose that Rip11 is an AS160- and Rab-binding protein that coordinates the protein kinase signalling and trafficking machinery required to stimulate glucose uptake in response to insulin.
Functional analysis of homeodomain-containing transcription factor Lbx1 in satellite cells of mouse skeletal muscle
Authors: Watanabe Shuichi , Kondo Shunzo , Hayasaka Michiko , Hanaoka Kazunori
Published: November 2007

Satellite cells are usually mitotically quiescent muscle stem cells, located between the sarcolemma and the basement membrane of muscle fibers. When muscles are damaged, satellite cells become activated, proliferate and differentiate to form multinucleate myofibers. The molecular mechanisms underlying these processes are poorly understood. In the present study, we found that, following treatment with cardiotoxin, homeodomain-containing transcription factor Lbx1 was strongly expressed in the satellite cells of regenerating adult skeletal muscle. Our immunohistochemical and northern blot analyses indicate that Lbx1 is expressed in activated but not quiescent satellite cells. In vitro, this Lbx1 expression was gradually downregulated when satellite cells differentiate into mature myofibers. Transfection and forced expression of Lbx1 in satellite-cell-derived C2C12 myoblast cells resulted in severe depression of myogenic differentiation and incomplete myotube formation, concomitantly with the activation of the paired-box transcription factor Pax7 and depression of the myogenic regulatory factor MyoD. Moreover, knockdown of Lbx1 in in-vitro-cultured satellite cells resulted in downregulation of Pax7. These results suggest that Lbx1 plays important roles in differentiation and maintenance of satellite cells of mature myofibers, probably through the regulation of Pax7.
The cataract-inducing S50P mutation in Cx50 dominantly alters the channel gating of wild-type lens connexins
Authors: DeRosa Adam M. , Xia Chun-Hong , Gong Xiaohua , White Thomas W.
Published: November 2007

Mutations within connexin50 (Cx50) have been linked to various cataract phenotypes. To determine the mechanism behind cataract formation we used the paired Xenopus oocyte system in conjunction with transfected HeLa cells and genetically engineered mouse models to examine the functional characteristics of gap junctions in which a cataract-causing mutant of Cx50 (hereafter referred to as Cx50-S50P) is expressed. Channels comprising Cx50-S50P subunits alone failed to induce electrical coupling. However, the mixed expression of Cx50-S50P and wild-type subunits of either Cx50 or Cx46 – to create heteromeric gap junctions – resulted in functional intercellular channels with altered voltage-gating properties compared with homotypic wild-type channels. Additionally, immunofluorescence microscopy showed that channels of Cx50-S50P subunits alone failed to localize to the plasma membrane – unlike channels composed of Cx46 subunits, which concentrated at cell-cell appositions. Cx50-S50P colocalized with wild-type Cx46 in both transfected HeLa cells in vitro and mouse lens sections in vivo. Taken together, these data define the electrophysiological properties and intracellular targeting of gap junctions formed by the heteromeric combination of Cx50 or Cx46 and Cx50-S50P mutant proteins. Additionally, mixed channels displayed significantly altered gating properties, a phenomenon that may contribute to the cataract that is associated with this mutation.
Static forces and torques in mechanisms with plane joints, with application to the Tracta coupling
Authors: Fischer I S
Published: November 2007

The force and torque components acting on revolute and plane joints are partitioned in a novel way so that the equations of static equilibrium can be written in a standard form, applicable to a single-loop mechanism with any number of links and any kinds of joints, with particular attention given to the plane joint which consists of two flat surfaces held in contact to permit one rotational and two translational degrees of freedom. The analysis utilizes the 3 × 3 dual-number coordinate-transformation matrix to model joints and links and expresses force and torque as a two-component dual force, which formulates the results in a compact form amenable for object-oriented programming to calculate the static loads. Particular attention is given to the Tracta coupling, an RRERR mechanism (rotation-rotation-plane-rotation-rotation joints) which has been used as a constant-velocity shaft coupling and features a plane joint. The formulation allows force and torque components to be expressed so to correspond to displacements specified with respect to the axes of intermediate coordinate frames in the modelling of a plane joint.
Rough collision in three-dimensional rigid multi-body systems
Authors: Elkaranshawy H A
Published: November 2007

In the current paper, single point rough collision in three-dimensional rigid multibody systems is modelled. Coulomb's friction law and infinite tangential stiffness are assumed. Routh's incremental model with energetic coefficient of restitution is used. Equations of motion are developed by means of Lagrangian formulation. The non-linear equations of motion show that the contact point could continuously change its sliding direction or the sliding could halt and the non-sliding persists or it could restart along a new direction. All these possible sliding behaviours during impact are identified, conditions leading to each behaviour are specified, and an appropriate numerical procedure is suggested. Normal impulse at the contact point is considered the independent variable, as time-like, to carry out the numerical integrations of the equations of motion. A case of a four-degrees-of-freedom spatial robot that collides with its environment is investigated. Solutions describing the variation of collision variables are obtained. It is recognized that qualitative changes to all the variables occur whenever sliding velocity reaches its minimum value. These critical spots are identified, the associated abrupt variations in the impact variables are explored and the friction influence is observed.
Identification of yeast tRNA Um44 2′-O-methyltransferase (Trm44) and demonstration of a Trm44 role in sustaining levels of specific tRNASer species
Authors: Kotelawala Lakmal , Grayhack Elizabeth J. , Phizicky Eric M.
Published: November 2007

A characteristic feature of tRNAs is the numerous modifications found throughout their sequences, which are highly conserved and often have important roles. Um44 is highly conserved among eukaryotic cytoplasmic tRNAs with a long variable loop and unique to tRNASer in yeast. We show here that the yeast ORF YPL030w (now named TRM44) encodes tRNASer Um44 2′-O-methyltransferase. Trm44 was identified by screening a yeast genomic library of affinity purified proteins for activity and verified by showing that a trm44-Δ strain lacks 2′-O-methyltransferase activity and has undetectable levels of Um44 in its tRNASer and by showing that Trm44 purified from Escherichia coli 2′-O-methylates U44 of tRNASer in vitro. Trm44 is conserved among metazoans and fungi, consistent with the conservation of Um44 in eukaryotic tRNAs, but surprisingly, Trm44 is not found in plants. Although trm44-Δ mutants have no detectable growth defect, TRM44 is required for survival at 33°C in a tan1-Δ mutant strain, which lacks ac4C12 in tRNASer and tRNALeu. At nonpermissive temperature, a trm44-Δ tan1-Δ mutant strain has reduced levels of tRNASer(CGA) and tRNASer(UGA), but not other tRNASer or tRNALeu species. The trm44-Δ tan1-Δ growth defect is suppressed by addition of multiple copies of tRNASer(CGA) and tRNASer(UGA), directly implicating these tRNASer species in this phenotype. The reduction of specific tRNASer species in a trm44-Δ tan1-Δ mutant underscores the importance of tRNA modifications in sustaining tRNA levels and further emphasizes that tRNAs undergo quality control.
Optimality Inequalities for Average Cost Markov Decision Processes and the Stochastic Cash Balance Problem
Authors: Feinberg Eugene A. , Lewis Mark E.
Published: November 2007

For general state and action space Markov decision processes, we present sufficient conditions for the existence of solutions of the average cost optimality inequalities. These conditions also imply the convergence of both the optimal discounted cost value function and policies to the corresponding objects for the average costs per unit time case. Inventory models are natural applications of our results. We describe structural properties of average cost optimal policies for the cash balance problem; an inventory control problem where the demand may be negative and the decision-maker can produce or scrap inventory. We also show the convergence of optimal thresholds in the finite horizon case to those under the expected discounted cost criterion and those under the expected discounted costs to those under the average costs per unit time criterion.
Solving the Capacitated Location-Routing Problem by a Cooperative Lagrangean Relaxation-Granular Tabu Search Heuristic
Authors: Prins Christian , Prodhon Caroline , Ruiz Angel , Soriano Patrick , Wolfler Calvo Roberto
Published: November 2007

Most of the time in a distribution system, depot location and vehicle routing are interdependent, and recent studies have shown that the overall system cost may be excessive if routing decisions are ignored when locating depots. The location-routing problem (LRP) overcomes this drawback by simultaneously tackling location and routing decisions. This paper presents a cooperative metaheuristic to solve the LRP with capacitated routes and depots. The principle is to alternate between a depot location phase and a routing phase, exchanging information on the most promising edges. In the first phase, the routes and their customers are aggregated into supercustomers, leading to a facility-location problem, which is then solved by a Lagrangean relaxation of the assignment constraints. In the second phase, the routes from the resulting multidepot vehicle-routing problem (VRP) are improved using a granular tabu search (GTS) heuristic. At the end of each global iteration, information about the edges most often used is recorded to be used in the following phases. The method is evaluated on three sets of randomly generated instances and compared with other heuristics and a lower bound. Solutions are obtained in a reasonable amount of time for such a strategic problem and show that this metaheuristic outperforms other methods on various kinds of instances.
A Dynamic Stochastic Model for the Single Airport Ground Holding Problem
Authors: Mukherjee Avijit , Hansen Mark
Published: November 2007

In this paper, we present a dynamic stochastic integer programming (IP) model for the single airport ground holding problem, in which ground delays assigned to flights can be revised during different decision stages, based on weather forecasts. The performance gain from our model is particularly significant in the following cases: (1) under stringent ground holding policy, (2) when an early ground delay program (GDP) cancellation is likely, and (3) for airports where the ratio between adverse and fair weather capacities is lower. The choice of ground delay cost component in the objective function strongly affects the allocation policy. When it is linear, the optimal solution involves releasing the long-haul flights at or near their scheduled departure times and using the short-haul flights to absorb delays if low-capacity scenarios eventuate. This policy resembles the current practice of exempting long-distance flights during ground delay programs. For certain convex ground delay cost functions, the spread of ground delay is more or less uniform across all categories of flights, which makes the overall delay assignment more equitable. Finally, we also present a methodology that could enable intra-airline flight substitutions by airlines after our model has been executed and scenario-specific slots have been assigned to all flights, and hence to the airlines that operate them. This makes our model applicable under the collaborative decision making (CDM) paradigm by allowing airlines to perform cancellations and substitutions and hence reoptimize their internal delay cost functions.
“Borough Politics” and “County Government” Administrative Styles in the Old Structure
Authors: Karran Terence
Published: November 2007

Most studies of local outputs in Britain focus on urban authorities, use simplistic measures of the political system and pay little attention to the importance of the administrative system. In this paper an attempt is made to remedy these deficiencies by constructing a comprehensive causal model of output determination in county authorities. The model reveals that in the counties, unlike the boroughs, the impact of political parties is less crucial to the determination of expenditure than modes of policy making and administrative system factors. After comparing these results with parallel county borough findings, they are lodged within existing case studies in order to account for the differences between output determination in rural and urban authorities. The low impact of parties and the predominant influence of administrative system factors in the counties are seen to result from the vestiges of rural culture, with its emphasis on ascribed status and consensus politics, the size of the counties and their councils, which hampered attempts by local parties to act as policy making bodies and necessitated that decisions be made by committees, and the heritage of an ethos of efficient administration.
Ambiguity and Obscurity in Policy-Making for Social Security
Authors: Bolderson Helen
Published: November 2007

The article offers some explanations for the different responses to recent developments in British social security policy. Lack of opposition to reductions in national insurance benefits in 1980 is contrasted with resistance put up to the employers’ statutory sickness benefit scheme. Following Derthick’s analysis of American social security policy-making, it is suggested that major policy shifts in the 1980 benefit changes were not recognised because of the ambiguity and technicality of the British national insurance scheme; because of the incremental nature of the politics which surround issues about who loses and who wins within the scheme; and because of the particular characteristics of the practitioner and consumer groupings in social security which do not provide a power base from which to challenge such developments. By contrast the proposal to introduce the employers’ statutory sickness benefit scheme visibly and unmistakably affected the boundaries of the public and private sectors and involved external organised interest groups.
Formulation and Implementation of Air Quality Control Programmes: Patterns of Interest Consideration
Authors: Knoepfel Peter , Weidner Helmut
Published: November 2007

This article investigates some central aspects of the relationships between programme structure and implementation of sulphur dioxide air quality control policies. Previous implementation research, primarily adopting American approaches, has neglected the connections between the processes of programme formulation and implementation. ‘Programme’, as the key variable in implementation studies, has been defined too narrowly. On the basis of theoretical and conceptual reflections and provisional empirical results from studies in France, Italy, England, and the Federal Republic of Germany, the authors demonstrate that an integral process analysis using a more extended programme concept is necessary if patterns of interest recognition in policies are to be discovered. Otherwise, the still important question of critical social science cannot be answered, namely, what is the impact of special interests upon implementation processes.
The Withdrawal of Mortgage Tax Relief: a survey and evaluation of the debate
Authors: Wilkinson M. , Wilkinson R. K.
Published: November 2007

Criticisms of mortgage tax relief have come from several quarters in recent years but they have been rejected by successive governments. We present here estimates of the distribution of this subsidy to owner-occupation and show, contrary to the claims of the Housing Consultative Document (1977), that it has some tendency to be regressive. The justification for continuing this policy, including that advanced in the Green Paper, is then critically examined in light of an economic analysis of effects. It is concluded that the gradual withdrawal of the subsidy would increase equity and efficiency in housing policy.
Ambivalence and Altruism: Public Opinion about Taxation and Welfare
Authors: Beedle Paul , Taylor-Gooby Peter
Published: November 2007

This paper relates the findings of an exploratory study of opinions on the role of the state in welfare to issues of social integration. The focus is on public opinion about the interrelation of welfare provision and the means used by governments to finance it. The analysis shows that ideas in this area are complex and that value judgements about the nature of the welfare state appear to playas important a role as conceptions of self-interest. The suggestion of some recent writing that divisions on the lines of perceived group interest threaten social legitimacy is not confirmed. However, there is also little evidence for the view that state welfare provision may playa strong positive role in generating a moral commitment to social integration. The considerations that influence people’s judgements reflect a complex interpenetration of the interests on the one hand and evaluations on the other that underlie each of these positions.
Policy, Bargaining and Structure in Implementation Theory: Towards an Integrated Perspective
Authors: Barrett Susan , Hill Michael
Published: November 2007

This theoretical and conceptual article expounds an approach to the study of implementation which sees it as an integral part of the policy process rather than an administrative ‘follow on’ from policy making. It therefore argues for the need to work with a stance on the concept of policy which sees it as complex and ambiguous, and the need to recognise the importance of the policy-action continuum. From that position it goes on to emphasise the importance of negotiation and bargaining in implementation, and to stress the significance of the relationship between policy content and policy context. It argues for, therefore, the development of the kind of approach to that relationship developed in work by Knoepfel and Weidner which is seen as opening up a way to handle questions of interest conflict and to relate implementation to the wider social and political structure.
Modelling the Policy/Implementation Distinction: The Case of Child Abuse
Authors: Whitmore Roger
Published: November 2007

The article addresses the policy/implementation distinction in relation to the development of child abuse policy in Britain. Eschewing such a conceptual distinction, a multi-dimensional model is adopted which, modified after Knoepfel and Weidner, uses the idea of a policy core embedded in layers of programme shells which are necessary if action is to take place. Their onion-like metaphor uses a relatively loose terminology in order to capture the interactive nature of processes within and between dimensions while allowing the key interests associated with child abuse policy to be investigated. In its modified form, the model also provides empirical referents which reveal the nature of the context within which these interests operate.
The Politics of Scottish Housing Plans
Authors: Midwinter Arthur , Keating Michael , Taylor Peter
Published: November 2007

The Scottish Housing Plan system was intended to bring about a radical change in the relationship between central and local government, by giving authorities greater scope to devise policies relative to local needs. In practice, Housing Plans provide a formal framework around which bargaining and negotiation takes place. Developments since 1979, however, have resulted in the abandonment of local government having a central, comprehensive role in housing provision.

The Housing Plan system has had an important influence on the pattern of central-local relations, but the original hopes for the Housing Plan system, of a more rational, integrated approach, remain unfulfilled. The air of technocratic dominance which featured heavily in the theoretical arguments for the system has been superseded by the operation of political bargaining. Housing Plans are a key mechanism within the policy framework, although not in the way intended by its progenitors.
Local Corporatism? The role of organisations and local movements in the local welfare state
Authors: Villadsen Søren
Published: November 2007

With the very high level of local government activity in Scandinavia the role of local organisations, movements etc. becomes crucial. Very little research has been done to evaluate the importance of ‘organised politicisation’ at the local level, with some notable exceptions analysed in the article. Three rather different versions of local corporatism are evaluated in the light of results from a major research project covering local organisations, parties, local councils, and other agencies in Danish local politics.

Local corporatism is rejected as a useful, general concept, but it is considered useful in the attempt to construct a new framework including central-local, local and spatial relations.
Corticospinal Dysgenesis and Upper-Limb Deficits in Congenital Hemiplegia: A Diffusion Tensor Imaging Study
Authors: Bleyenheuft Yannick , Grandin Cécile B. , Cosnard Guy , Olivier Etienne , Thonnard Jean-Louis
Published: November 2007

OBJECTIVES. Precision grasping critically relies on the integrity of the corticospinal tract as evidenced in congenital hemiplegia by the correlation found between corticospinal dysgenesis and hand-movement deficits. Therefore, corticospinal dysgenesis could be used to anticipate upper-limb deficits in young infants with congenital hemiplegia. However, most studies have quantified corticospinal dysgenesis by measuring the cross-sectional area of cerebral peduncles on T1 MRI, a measure biased by other structures present in the peduncles. The purpose of this study was to evaluate the extent to which this may have hampered the conclusions of previous studies. We also aimed to investigate the relationship between upper-limb deficits and a more accurate measure of corticospinal dysgenesis to provide a tool for anticipating upper-limb deficits in infants with congenital hemiplegia.

METHODS. To address this issue, we measured corticospinal tract areas in 12 patients with congenital hemiplegia and 12 matched control subjects by using the diffusion tensor imaging technique. Corticospinal dysgenesis was quantified by computing a symmetry index between the area of the contralateral and ipsilateral corticospinal tracts. This value was then compared with that resulting from the conventional MRI method.

RESULTS. The symmetry indexes gathered with these 2 methods were highly correlated, although the diffusion tensor imaging symmetry indexes were significantly smaller. This indicates that, in patients with congenital hemiplegia, the conventional MRI measurement has led to a systematic underestimate of corticospinal dysgenesis. These 2 estimates of corticospinal dysgenesis were also correlated with upper-limb impairments and disabilities. Although the symmetry index computed from peduncle measurements was correlated solely with deficits in stereognosis, the diffusion tensor imaging index correlated with stereognosis, digital and manual dexterities, and ABILHAND-Kids, a measure of manual ability in daily life activities.

CONCLUSIONS. The diffusion tensor imaging symmetry index provides a useful prognostic tool for anticipating upper-limb deficits and their consequences in daily life activities.
Laser stapedotomy – the up-to-date solution of otosclerotic stapes fixation
Authors: Gerlinger Imre , Bakó Péter , Szanyi István , Móricz Péter , Ráth Gábor , Lujber László , Moric Krisztina , Pytel József
Published: November 2007

A vezetéses halláscsökkenést okozó otoscleroticus stapesfixatio műtéti megoldásának folyamatos fejlődése az elmúlt fél évszázad egyik fülsebészeti sikertörténete. A stapedectomia, illetve parciális stapedectomia mellett manapság a stapedotomia is elterjedt műtéti megoldásnak tekinthető.Cél:A minimálisan invazív lézerstapedotomia hazai bevezetése, tapasztalatok szerzése, valamint a műtéti halláseredmények és a posztoperatív komplikációk elemzése.Módszer:A szerzők közleményükben KTP-lézerrel asszisztált, Nitinol-pisztonnal végzett 14 esetük kapcsán ismertetik lézerstapedotomiákkal szerzett első tapasztalataikat. 2006 márciusa és 2007 áprilisa között 11 nőbeteget és 3 férfi beteget operáltak. A betegek átlagéletkora 42,2 év volt, 6 esetben bal, 8 esetben jobb fülön történt a műtét. A betegek átlagos követési ideje 9 hónap volt.Eredmények:A posztoperatív audiogramok értékelésekor az 500–1000–2000–3000 Hz frekvenciákat figyelembe véve a légvezetés átlagos javulása 21,5 dB volt. Ugyanezen frekvenciákon a csontlégközértékek átlagos javulása 18,7 dB volt. Kilenc hónap átlagos követési idő mellett az eddigi esetekben a műtéteket követően a betegek 85%-ában az átlagos csontlégköz < 10 dB, de valamennyi beteg esetében < 20 dB. Az átlagos légvezetés értéke egy beteg kivételével < 30 dB. Belsőfül-károsodásra utaló, a magashang-frekvenciákat érintő csontvezetéses romlást, facialis paresist nem észleltek.Következtetések:A szerzők tapasztalatai és az irodalmi adatok alapján a Nitinol-pisztonnal végzett lézerstapedotomiáknak számos előnyük van: 1) a piszton hurkának hőre aktiválódó memóriaeffektusa kiküszöböli az incus hosszú szárára két ponton történő rászorítás hátrányait; 2) a posztoperatív szédülés mértéke enyhébb, időtartama rövidebb, ezért az ápolási idő csökken; 3) a műtét költséghatékony, és minimálisan invazív; 4) a lézer alkalmazása minimális cochlearis traumát, vérmentes környezetet biztosít; 5) a protézis migrációja kiküszöbölhető, körülötte a granuláció mérsékeltebb; 6) magas frekvenciákon tartósan jó halláseredmény érhető el; 7) a komplikációk súlyossága, gyakorisága csökken, ezért a technika jó megoldás kevésbé gyakorlott operatőrök számára is; 8) problémás esetekben (arteria stapedialis jelenléte, obliterativ otosclerosis, úszó stapestalp, rendellenesen futó n. facialis a dobüregben, revíziós műtétek) is alkalmazható; 9) a halláseredmények interindividuális különbsége kisebb. – Eddigi kedvező tapasztalataik alapján a szerzők lézerstapedotomián átesettek hosszú távú követését tervezik nagyobb beteganyagon.
Avaliação do risco cardiovascular segundo os critérios de Framingham em pacientes com diabetes tipo 2
Authors: Oliveira Dhiãnah S. , Tannus Lucianne R.M. , Matheus Alessandra S.M. , Corrêa Fernanda H. , Cobas Roberta , Cunha Edna F. da , Gomes Marília B.
Published: November 2007

OBJETIVO: Avaliar o risco cardiovascular (RCV) em pacientes com diabetes tipo 2 (DM2) de acordo com os critérios de Framingham, e sua associação com outros fatores não incluídos no escore de Framingham. DESENHO DO ESTUDO E MÉTODOS: Foram avaliados, em corte transverso, 333 pacientes DM2 (215 do sexo feminino) com média de idade de 59,6 ± 9,7 anos, acompanhados no Serviço de Diabetes e Metabologia do HUPE no período de março de 2004 a fevereiro de 2005. A duração conhecida do diabetes foi de 12 (0 a 43) anos. Foi aplicado o escore de Framingham em todos os pacientes para determinação do risco de morte por doença coronariana. Os pacientes foram estratificados em grupos quanto ao RCV em 10 anos: < 20% e > 20% de probabilidade de apresentar um evento CV. RESULTADOS: O RCV, em 10 anos na amostra estudada, foi de 18,7 ± 10,8%, sendo maior no sexo masculino do que no feminino [20% (253) vs. 15% (127), p< 0,001]. A prevalência de risco > 20% do escore de Framingham foi maior no sexo masculino (55,1%) do que no feminino (38,6%) (p= 0,003). O RCV foi correlacionado à duração conhecida do DM, níveis de triglicerídeos (TGs), creatinina, glicemia pós-prandial e circunferência abdominal (CA). Houve associação do RCV com a CA, pela classificação da IDF (International Diabetes Federation) (p< 0,001) e Organização Mundial de Saúde (OMS) (p= 0,003). Na regressão múltipla em stepwise, encontramos correlação significativa e independente do RCV com as seguintes variáveis: sexo masculino, duração conhecida do DM, creatinina plasmática, CA e TGs (p< 0,001). CONCLUSÕES: A população diabética estudada apresentou alto risco para eventos cardiovasculares segundo os critérios de Framingham, principalmente os pacientes do sexo masculino. Considerando-se o elevado custo das investigações cardiológicas para o sistema de saúde público, estudos posteriores poderão ratificar se a aplicação rotineira deste escore, prático e não-invasivo, permitiria um melhor direcionamento na solicitação destas investigações. Isto poderia resultar na adoção de medidas de intervenção mais precoces e intensivas nos pacientes, no sentido de reduzir ou controlar o risco coronariano.
Hiperlipidemias e fatores dietéticos: estudo transversal entre nipo-brasileiros
Authors: Bevilacqua Marselle R. , Gimeno Suely G.A. , Matsumura Luiza K. , Ferreira Sandra R.G.
Published: November 2007

Este estudo teve como objetivo avaliar a associação entre hiperlipidemia e dieta de nipo-brasileiros de Bauru, município do Estado de São Paulo. Foram obtidos de 1.330 indivíduos dados mediante questionários previamente testados (dados demográficos e dietéticos). Os exames físicos e laboratoriais incluíram a coleta (ou dosagem) antropométrica, de pressão arterial, de glicemia de jejum e de 2 horas, de perfil lipídico e de TSH e T4 livre. Utilizaram-se teste qui-quadrado e medida de odds ratio para avaliar associação entre as variáveis estudadas e presença de hiperlipidemia. Foi encontrado 81,5% de hiperlipidêmicos e acometeu, principalmente, indivíduos tabagistas, com excesso de peso, hipotireoidismo, hipertensão arterial e intolerância a glicose. Observaram-se, mediante análise bruta, relações entre hiperlipidemia e ácido graxo saturado, ácido oléico e fibras de grãos e cereais. Após o ajuste para as variáveis de controle, observaram-se associações entre hiperlipidemia e consumo de lípides (totais, ácido oléico, saturados e trans), fibras e álcool. Conclui-se que mudanças no estilo de vida, particularmente no hábito alimentar, podem levar a uma melhora do quadro hiperlipidêmico e que o consumo de lípides pode ser um dos principais fatores para o aumento da hiperlipidemia. Estudos prospectivos auxiliarão para testar essas hipóteses nos nipo-brasileiros de Bauru.
A Colônia enferma e a saúde dos povos: a medicina das 'luzes' e as informações sobre as enfermidades da América portuguesa
Authors: Abreu Jean Luiz Neves
Published: November 2007

Os avanços da medicina no conhecimento do corpo humano e nas formas de tratar as enfermidades não tiveram impacto somente sobre o corpo individual. A partir do século das luzes a medicina passou a se preocupar cada vez mais com a 'saúde dos povos'. Os conhecimentos oriundos de novas teorias médicas passaram a ser postos a serviço do Estado, possibilitando formas mais eficazes de diminuir as epidemias e a alta mortalidade. Este artigo pretende examinar o significado que tais mudanças na medicina assumiram para o Estado português, abordando seus impactos no universo colonial com base na questão das enfermidades dos negros e do estabelecimento de informações acerca das enfermidades na América portuguesa.
Um manuscrito inédito do naturalista e político Martim Francisco Ribeiro de Andrada
Authors: Varela Alex Gonçalves
Published: November 2007

Martim Francisco Ribeiro de Andrada foi um dos expoentes da ilustração luso-americana. Seus perfis de naturalista e político são indissociáveis, característica típica dos ilustrados do Setecentos. No cargo de ministro da Fazenda, redigiu a "Memória sobre a estatística ou análise dos verdadeiros princípios desta ciência e sua aplicação à riqueza, artes e poder do Brasil", estudo que permaneceu inédito até os nossos dias, no arquivo do Instituto Histórico e Geográfico Brasileiro. O texto demonstra o quanto ciência e política caminhavam amalgamadas no final do século XVIII e início do XIX.
Dinâmica fermentativa e microbiológica de silagens dos capins tanzânia e marandu acrescidas de polpa cítrica peletizada
Authors: Coan Rogério Marchiori , Reis Ricardo Andrade , Garcia Gisela Rojas , Schocken- Iturrino Ruben Pablo , Ferreira Daniel de Souza , Resende Flávio Dutra de , Gurgel Felipe do Amaral
Published: November 2007

O experimento foi conduzido com o objetivo de avaliar a dinâmica fermentativa e microbiológica de silagens de capins tropicais acrescidas de polpa cítrica. Os capins tanzânia (Panicum maximum cv. Tanzânia) e marandu (Brachiaria brizantha (Hochst ex. A. Rich) Stapf cv. Marandu) foram colhidos aos 64 e 49 dias de rebrota, respectivamente, e ensilados com 0, 5 ou 10% de polpa cítrica peletizada (PCP), em relação à matéria verde, durante 1, 4, 7, 14, 21, 28 e 56 dias. Foram utilizados silos experimentais de PVC adaptados com válvula do tipo Bunsen para eliminação dos gases. A forragem foi compactada visando obter densidade de 550 kg/m³. O delineamento utilizado foi o inteiramente ao acaso com três repetições, em esquema de parcelas subdivididas. A inclusão de PCP aumentou os teores de MS e diminuiu o pH das silagens. A adição de PCP influenciou os teores de N-NH3 (N total), uma vez que, nas silagens sem PCP, os teores N-NH3 foram significativamente elevados, o que as caracteriza como de qualidade duvidosa. A adição de PCP aumentou a concentração molar dos ácidos acético e propiônico. A população de enterobactérias foi detectada somente no primeiro dia de fermentação nas silagens do capim-tanzânia e até o 18º dia nas do capim-marandu. Nas silagens avaliadas, a população de bactérias homofermentativas foi semelhante à das bactérias heterofermentativas.
Objetivos de seleção e valores econômicos em sistemas de produção de gado de corte no Brasil
Authors: Jorge Júnior João , Cardoso Vera Lucia , Albuquerque Lucia Galvão de
Published: November 2007

A importância econômica de possíveis características biológicas a serem incluídas em objetivos de seleção para diferentes sistemas de produção de bovinos da raça Nelore, mediante o cálculo dos seus valores econômicos foi avaliada nesta pesquisa. Com base em informações de desempenho e parâmetros biológicos e econômicos, foram simulados diferentes sistemas de produção (ciclos de cria e completo) para dois rebanhos. O rebanho 1, com ciclo de cria (Ccr), ciclo completo (Cco) e ciclo completo com venda de reprodutores (CcoR), é um rebanho elite no qual é desenvolvido um programa seleção. Parte deste rebanho é também destinada à produção de animais comerciais. O rebanho 2 é um rebanho exclusivamente comercial, com Ccr e Cco. Os valores econômicos foram calculados usando-se um modelo bio-econômico, para as seguintes características: peso (PD) e taxa de desmama (TD), peso da vaca adulta (PVA), ganho médio diário no confinamento (GMD), pesos ao abate (PA) e de carcaça (PC), peso final dos tourinhos (PFT), rendimento de carcaça (RC) e consumo alimentar no confinamento (CAc) e em pastagem (CAp). Para os sistemas de ciclo completo e de ciclo completo com venda de reprodutores e CcoR (Cco e CcoR), os valores econômicos variaram de R$ 0,34 a R$ 0,40 para PD, R$ 3,51 a R$ 10,15 para TD, -R$ 0,16 a R$ 0,09 para PAV, R$ 0,32 a R$ 0,76 para GMDc, R$ 1,09 a R$ 1,17 para PA; R$ 2,03 a R$ 2,19 para PC, R$ 23,89 a R$ 28,61 para RC, e R$ 11,85 para PFT, - R$0,45 para CAc e - R$ 0,03 para CAp. A taxa de desmama e o rendimento de carcaça foram as características de maior impacto no lucro anual dos dois rebanhos. As análises de sensibilidade demonstraram que, de modo geral, possíveis mudanças nos preços de insumos e produtos influenciariam de forma mais significativa os valores econômicos nos sistemas de produção nos quais esses preços eram mais elevados nas situações básicas.
Níveis de proteína bruta e suplementação de aminoácidos em rações para leitoas dos 30 aos 60 kg mantidas em ambiente de alta temperatura
Authors: Orlando Uislei Antonio Dias , Oliveira Rita Flávia Miranda de , Donzele Juarez Lopes , Silva Francisco Carlos de Oliveira , Generoso Rafaela Antonia Ramos , Siqueira Jefferson Costa de
Published: November 2007

Foi realizado um estudo para avaliar níveis de proteína bruta (PB) e suplementação de aminoácidos em rações para leitoas mantidas em ambiente de alta temperatura (temperatura do ar de 30ºC, umidade relativa de 66,1% e ITGU calculado de 79,7) na fase de crescimento. Foram utilizadas 50 leitoas mestiças (Landrace ´ Large White) com peso inicial médio de 30,2 kg, em delineamento experimental inteiramente ao acaso, com cinco tratamentos e cinco repetições de dois animais por unidade experimental. Os tratamentos consistiram de cinco níveis de PB (19, 18, 17, 16 e 15%) na ração e da suplementação com lisina, metionina, triptofano, treonina e valina para manutenção da mesma qualidade protéica da ração. As rações experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram o peso médio de 60,1 kg. Não se observou efeito do nível de proteína bruta da ração sobre o desempenho dos animais (consumo de ração, ganho de peso e conversão alimentar). A deposição de proteína na carcaça também não foi influenciada pela redução do nível de PB da ração, pois os animais alimentados com a ração com 18% de PB apresentaram os maiores valores. Os níveis de PB na ração não influenciaram os pesos absoluto e relativo dos órgãos dos animais. O nível de PB da ração pode ser reduzido em até 4% (de 19 para 15% de PB), pois essa redução não altera o desempenho de leitoas mantidas em ambiente de alta temperatura na fase dos 30 aos 60 kg, desde que as rações sejam devidamente suplementadas com todos os aminoácidos essenciais.
Substituição do milho moído por casca de soja na ração de vacas leiteiras em confinamento
Authors: Pedroso Alexandre Mendonça , Santos Flávio Augusto Portela , Bittar Carla Maris Machado , Pires Alexandre Vaz , Martinez Junio Cesar
Published: November 2007

Trinta e seis vacas holandesas no terço médio da lactação, 123 dias em lactação (DEL), foram utilizadas para avaliar a substituição do milho moído (MM) por casca de soja (CS) em rações contendo silagem de milho como volumoso principal e polpa cítrica como parte da fonte energética. Foram avaliadas rações com 0, 10 e 20% de substituição do milho moído por casca de soja na ração, na MS da ração completa (%MS): CS 0 - 0% de CS e 20% de MM; CS 10: 10% de CS e 10% de MM; e CS 20 - 20% de CS e 0% MM. Características de desempenho e metabolismo como consumo de MS, produção e composição do leite, concentrações de N-uréico no leite e níveis de glicose plasmática foram avaliadas. As vacas foram distribuídas a um delineamento experimental em quadrado latino 3 ´ 3, com de 12 repetições e de acordo com a produção de leite, DEL e a paridade. A inclusão de CS nas rações não afetou o consumo de MS (22,84 kg/dia), a produção de leite (28,33 kg/dia) ou a produção de leite corrigida para 3,5 % gordura (28,48 kg/dia). No entanto, aumentou linearmente a produção total de gordura (kg/dia) e a decresceu linearmente a concentração de N-uréico no leite. A substituição do milho moído por casca de soja na alimentação de vacas leiteiras pode ser uma alternativa interessante, desde que o preço do subproduto seja competitivo.
Efeito da adubação nitrogenada e irrigação sobre a composição químico-bromatológica das lâminas foliares e da planta inteira de capim-elefante sob pastejo
Authors: Mistura Claudio , Fonseca Dilermando Miranda da , Moreira Luciano de Melo , Fagundes Jailson Lara , Morais Rodrigo Vieira , Queiroz Augusto César de , Ribeiro Júnior José Ivo
Published: November 2007

Esta pesquisa foi desenvolvida com o objetivo de avaliar o efeito da adubação nitrogenada (100, 200, 300, 400 kg/ha/ano de N) e da irrigação (área irrigada - AI e não-irrigada - ANI) sobre a composição quimico-bromatológica da planta inteira (PI) (colmo+folha) e das lâminas foliares dos perfilhos basais não-decapitados (LF-PBNd) e decapitados (LF-PBd) do capim-elefante cv. Napier. Adotou-se delineamento experimental em blocos casualizados com três repetições, em que a unidade experimental consistiu de parcelas (piquetes de 300 m²), nas quais foram aplicados os tratamentos. Os teores de PB apresentaram valores proporcionais às doses de nitrogênio, observando-se os maiores valores, no período das águas, nas LF-PBNd e LF-PBd. Os resíduos das doses N aplicados no período chuvoso tanto na AI como ANI elevaram os teores de PB nas lâminas foliares das duas categorias de perfilhos, mas não sobre os teores de FDN e FDA. A irrigação proporcionou teores de FDN e FDA mais elevados nas LF-PBNd e LF-PBd e menores na planta inteira, porém, não se observou efeito sobre os teores de PB.