bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of the Opening of the Bundle Crossing in KcsA with Fluorescence Lifetime Spectroscopy Reveals the Existence of Two Gates for Ion Conduction
Authors: Blunck Rikard , Cordero-Morales Julio F. , Cuello Luis G. , Perozo Eduardo , Bezanilla Francisco 
Published: October 2006

The closed KcsA channel structure revealed a crossing of the cytosolic ends of the transmembrane helices blocking the permeation pathway. It is generally agreed that during channel opening this helical bundle crossing has to widen in order to enable access to the inner cavity. Here, we address the question of whether the opening of the inner gate is sufficient for ion conduction, or if a second gate, located elsewhere, may interrupt the ion flow. We used fluorescence lifetime measurements on KcsA channels labeled with tetramethylrhodamine at residues in the C-terminal end of TM2 to report on the opening of the lower pore region.
We found two populations of channels with different fluorescence lifetimes, whose relative distribution agrees with the open probability of the channel. The absolute fraction of channels found with an open bundle crossing is too high to explain the low open probability of the KcsA-WT channel. We found the same distribution as in the WT channel between open and closed bundle crossing for two KcsA mutants, A73E and E71A, which significantly increase open probability at low pH. These two results strongly suggest that a second gate in the ion permeation pathway exists. The location of the mutations A73E and E71A suggests that the second gate may be the selectivity filter, which resides in an inactivated state under steady-state conditions. Since the long closed times observed in KcsA-WT are not present in KcsA-A73E or -E71A, we propose that KcsA-WT remains predominantly in a state with an open bundle crossing but closed (inactivated) second gate, while the mutations A73E and E71A sharply decrease the tendency to enter in the inactivated state, and as a consequence, the second gate is predominantly open at steady state. The ability to monitor the opening of the bundle crossing optically enables the direct recording of the movement of the pore helices while the channel is functioning.
Meta‐analysis: alvimopan vs. placebo in the treatment of post‐operative ileus
Authors: TAN E. K. , CORNISH J. , DARZI A. W. , TEKKIS P. P. 
Published: October 2006

SummaryBackgroundAlvimopan is a selective, competitive μ‐opioid receptor antagonist with limited oral bioavailability which may be used to reduce length of post‐operative ileus.AimThe study compared alvimopan with placebo following bowel resection or total abdominal hysterectomy.MethodsA meta‐analysis of randomized–controlled trials published between 2001 and 2006 of alvimopan vs. placebo was performed. The primary efficacy end‐points were composite measures of passage of flatus, stool, and tolerance of solid food (GI‐3) and passage of stool and tolerance of solid food (GI‐2). The incidence of treatment emergent adverse events was assessed.ResultsFive trials matched the selection criteria, reporting on 2195 patients. A total of 1521 (69.3%) had alvimopan and 674 (30.7%) placebo. GI‐3 significantly improved (hazard ratio 1.30; 95% confidence intervals 1.16, 1.45, P < 0.001), as did GI‐2 (hazard ratio 1.61; 95% confidence intervals 1.26, 2.05, P < 0.001) on alvimopan 12 mg. Time to discharge (hazard ratio 1.26; 95% confidence intervals 1.13, 1.40, P < 0.001), time to bowel motion (hazard ratio 1.74; 95% confidence intervals 1.29, 2.35, P < 0.001), and time to solid food (hazard ratio 1.14; 95% confidence intervals 1.01, 1.30, P < 0.04) also improved significantly. No difference was noted in the incidence of treatment emergent adverse events.ConclusionsAlvimopan showed significant advantages over placebo in restoring gastro‐intestinal function, and reduced time to discharge following major abdominal surgery, with acceptable side effects.
The ability of climate envelope models to predict the effect of climate change on species distributions
Authors: HIJMANS ROBERT J. , GRAHAM CATHERINE H. 
Published: October 2006

AbstractClimate envelope models (CEMs) have been used to predict the distribution of species under current, past, and future climatic conditions by inferring a species' environmental requirements from localities where it is currently known to occur. CEMs can be evaluated for their ability to predict current species distributions but it is unclear whether models that are successful in predicting current distributions are equally successful in predicting distributions under different climates (i.e. different regions or time periods). We evaluated the ability of CEMs to predict species distributions under different climates by comparing their predictions with those obtained with a mechanistic model (MM). In an MM the distribution of a species is modeled based on knowledge of a species' physiology. The potential distributions of 100 plant species were modeled with an MM for current conditions, a past climate reconstruction (21 000 years before present) and a future climate projection (double preindustrial CO2 conditions). Point localities extracted from the currently suitable area according to the MM were used to predict current, future, and past distributions with four CEMs covering a broad range of statistical approaches: Bioclim (percentile distributions), Domain (distance metric), GAM (general additive modeling), and Maxent (maximum entropy). Domain performed very poorly, strongly underestimating range sizes for past or future conditions. Maxent and GAM performed as well under current climates as under past and future climates. Bioclim slightly underestimated range sizes but the predicted ranges overlapped more with the ranges predicted with the MM than those predicted with GAM did. Ranges predicted with Maxent overlapped most with those produced with the MMs, but compared with the ranges predicted with GAM they were more variable and sometimes much too large. Our results suggest that some CEMs can indeed be used to predict species distributions under climate change, but individual modeling approaches should be validated for this purpose, and model choice could be made dependent on the purpose of a particular study.
Uncovering and responding to needs for sexual and reproductive health care among poor urban female adolescents in Nicaragua
Authors: Meuwissen Liesbeth E. , Gorter Anna C. , Segura Zoyla , Kester Arnold D. M. , Knottnerus J. A. 
Published: October 2006

SummaryBackground  To meet the needs of female adolescents from low‐income urban areas for sexual and reproductive health (SRH) care, vouchers providing free‐of‐charge access to SRH care at 19 primary care clinics were distributed in Managua, Nicaragua. These vouchers substantially increased the use of services, demonstrating that many adolescents are willing to use such services, if readily accessible. The voucher redemption made it possible to identify the nature of existing, but largely unmet, needs for SRH care.Method  The medical files from 3301 consultations with female adolescents were analysed using descriptive statistical methods and multiple logistic regression.Results  Female adolescents presented SRH problems that merited medical attention. The mean number of problems presented was 1.5 per consultation: 34% of the vouchers were used for contraceptives, 31% for complaints related to sexually transmitted infection (STI) or reproductive tract infection (RTI), 28% for advice/counselling, 28% for antenatal check‐up and 18% for pregnancy testing. A new category of health care users emerged: sexually active girls who were neither pregnant nor mothers and who sought contraceptives or STI/RTI treatment. Contraceptive use doubled among the sexually active non‐pregnant voucher redeemers. Consultation with a female doctor younger than 36 years was associated with a higher chance of having contraceptives prescribed.Conclusion  Accessible and appropriate SRH care has the potential to make an important contribution to the increased contraceptive use, decreased risk of unwanted teenage pregnancies and decreased prevalence of STIs/RTIs among underserved adolescents. Once adolescents access the services, providers have a crucial role in ensuring current and continuing needs are met.
Leishmania and sand flies: proximity to woodland as a risk factor for infection in a rural focus of visceral leishmaniasis in west central Venezuela
Authors: Feliciangeli M. Dora , Delgado Olinda , Suarez Benny , Bravo Arturo 
Published: October 2006

SummaryObjective  To relate entomological, epidemiological and geographical data to understand the transmission dynamics of visceral leishmaniasis (VL) in a closed focus in western Venezuela.Methods  Spatial and temporal patterns of Lutzomyia pseudolongipalpis, the most prevalent phlebotomine sand fly species (99.7%), were studied in El Brasilar, Curarigua, Lara State, Venezuela, a small rural community of 20 dwellings and 118 inhabitants. The sand fly population was monitored using Centers for Disease Control light traps monthly throughout 1 year in the domestic and sylvatic habitats and for 3 months in all inhabited houses.Results  Temporal variation followed the yearly bimodal pattern of precipitation with the highest population densities in April and December. Infection with flagellates suggestive of Leishmania spp. was detected in 0.01% of 10 026 dissected females of L. pseudolongipalpis, which proved to be highly endophilic. Prevalence of Leishmania infection in people, as measured by the leishmanin skin test, was correlated with distance of the houses from the woodland and with sand fly abundance. A logistic regression model showed that for people who live in the village, the proximity to the woodland (linear) should be considered a risk factor for Leishmania infection (binary) (z = −2.02, P = 0.04, OR = 0.98, 95% CI = 0.97–0.99). This was consistent with the association between the proportion of VL infection and the log of sand fly abundance, which was negatively correlated with distance from the woodland.Conclusion  We discuss strategies that might be useful in controlling VL transmission in this endemic focus.
Bupivacaine caudal epidural anesthesia: assessing the effect of general anesthetic technique on block onset
Authors: INGELMO P.M. , BENDALL E.J. , FRAWLEY G. , LOCATELLI B.G. , MILAN B. , LODETTI D. , FUMAGALLI R. 
Published: October 2006

SummaryBackground: The primary objective of this prospective, randomized trial was to compare the effect of propofol and sevoflurane on effectiveness of regional anesthesia. As a secondary objective, we aimed at evaluating the influence of age on neuraxial block profile.Methods: One hundred and thirteen healthy children aged <10 years, scheduled for general or urological surgical procedures were randomly allocated to receive either propofol or sevoflurane induction and maintenance. Children received caudal or lumbar epidural block depending on their weight and expected surgery. Time to onset of surgical anesthesia, intraoperative analgesic effectiveness, residual motor blockade, postoperative pain, and adverse effects were evaluated. To assess the influence of age on these measures children were further divided into three age groups: 0–24, 25–60 and >60 months.Results: The mean time to onset of surgical anesthesia was significantly shorter in the sevoflurane group than the propofol group (3.1 vs 4.7 min,P < 0.01), independent of the type of regional technique employed. Distress on arousal in recovery was increased in children receiving sevoflurane (P = 0.03). There was no significant difference in residual motor blockade between the groups but children between 0 and 24 months receiving sevoflurane had a higher incidence of residual motor blockade 3 h after local anesthetic injection (P = 0.01).Conclusions: This study has demonstrated that general anesthesia with sevoflurane decreases the time to onset of surgical anesthesia relative to propofol anesthesia. This effect was most marked when sevoflurane anesthesia preceded caudal epidural blockade. The basis for this effect is most likely to be related to differential binding of the two anesthetic agents to receptors in the spinal cord that mediate immobility in response to surgical stimuli.
Relief of chronic partial ureteral obstruction attenuates salt‐sensitive hypertension in rats
Authors: Carlström M. , Wåhlin N. , Skøtt O. , Persson A. E. G. 
Published: October 2006

AbstractAim:  The incidence of hydronephrosis due to ureteropelvic junction obstruction is approx. 0.5%. During the last decade, the management of non‐symptomatic hydronephrosis has become much more conservative, but the long‐term physiological consequences of this policy are not clear. Previously, we have shown that animals with chronic partial unilateral ureteral obstruction develop salt‐sensitive hypertension. In this study, the effects of ipsilateral and contralateral nephrectomy and ureterovesicostomy on blood pressure were studied in hydronephrotic animals.Methods:  Partial unilateral ureteral obstruction was created in 3‐week‐old male Sprague–Dawley rats and blood pressure was measured telemetrically 4–6 weeks later during a normal and high salt diet before and after uninephrectomy or ureterovesicostomy. Plasma samples for renin assay were collected during both diets before and after ipsilateral nephrectomy.Results:  All hydronephrotic animals developed salt‐sensitive hypertension, of different degrees. Before nephrectomy the plasma renin concentration was significantly higher in the hydronephrotic animals than in controls (160 ± 15 μGU mL−1 vs. 96 ± 12 μGU mL−1, respectively), but after the ipsilateral nephrectomy no differences were found between the groups. In the hydronephrotic animals both ipsilateral nephrectomy and ureterovesicostomy reduced the blood pressure and salt‐sensitivity but the former still differed significantly from the controls. In contralaterally, nephrectomized hydronephrotic animals the salt‐sensitive hypertension became more pronounced.Conclusion:  Hydronephrosis in rats causes salt‐sensitive hypertension that can be markedly reduced by removing the hydronephrotic kidney or relieving the obstruction by ureterovesicostomy. The mechanisms appear to be intrarenal and primarily located in the diseased kidney, but a secondary mechanism is also present.
Exposure to carcinogens for defined job categories in Norway’s offshore petroleum industry, 1970 to 2005
Authors: Steinsvåg Kjersti , Bråtveit Magne , Moen Bente E 
Published: October 2006

Objectives:To identify and describe the exposure to selected known and suspected carcinogenic agents, mixtures and exposure circumstances for defined job categories in Norway’s offshore petroleum industry from 1970 to 2005, in order to provide exposure information for a planned cohort study on cancer.Methods:Background information on possible exposure was obtained through company visits, including interviewing key personnel (n = 83) and collecting monitoring reports (n = 118) and other relevant documents (n = 329). On the basis of a previous questionnaire administered to present and former offshore employees in 1998, 27 job categories were defined.Results:This study indicated possible exposure to 18 known and suspected carcinogenic agents, mixtures or exposure circumstances. Monitoring reports were obtained on seven agents (benzene, mineral oil mist and vapour, respirable and total dust, asbestos fibres, refractory ceramic fibres, formaldehyde and tetrachloroethylene). The mean exposure level of 367 personal samples of benzene was 0.037 ppm (range: less than the limit of detection to 2.6 ppm). Asbestos fibres were detected (0.03 fibres/cm3) when asbestos-containing brake bands were used in drilling draw work in 1988. Personal samples of formaldehyde in the process area ranged from 0.06 to 0.29 mg/m3. Descriptions of products containing known and suspected carcinogens, exposure sources and processes were extracted from the collected documentation and the interviews of key personnel.Conclusions:This study described exposure to 18 known and suspected carcinogenic agents, mixtures and exposure circumstances for 27 job categories in Norway’s offshore petroleum industry. For a planned cohort study on cancer, quantitative estimates of exposure to benzene, and mineral oil mist and vapour might be developed. For the other agents, information in the present study can be used for further assessment of exposure, for instance, by expert judgement. More systematic exposure surveillance is needed in this industry. For future studies, new monitoring programmes need to be implemented.
MUSCLES WITHIN MUSCLES: A MECHANOMYOGRAPHIC ANALYSIS OF MUSCLE SEGMENT CONTRACTILE PROPERTIES WITHIN HUMAN GLUTEUS MAXIMUS
Authors: McAndrew D. , Gorelick M. , Brown J. M. M. 
Published: October 2006

The aim of this investigation was to determine the contractile properties of motor units within 3 segments of the gluteus maximus utilizing a laser-based mechanomyographic (MMG) technique. The intention was to determine whether there were segmental differences in motor unit contractile properties and whether these differences may be related to the muscle segment's function and its fibre type composition.Ten subjects were recruited from the student population at the University of Wollongong. Maximal percutaneous neuromuscular stimulation (PNS) was delivered to the medial and lateral portions of three (cranial, middle, caudal) muscle segments of the gluteus maximus by an MMG stimulator. An MMG laser sensor measured the lateral displacement of the muscle segment belly resulting from the development of maximal isometric tension. Parameters characterizing the MMG waveforms were statistically compared to determine variations in contractile properties both within (medial to lateral) and between segments.Our results indicated that the contractile properties of motor units varied significantly (p < 0.05) between, but not within (medial to lateral), the three segments of the gluteus maximus. Most the gluteus maximus. Most notably, segment contraction time (tc) decreased significantly (p < 0.05) in a cranio to caudal direction suggesting a variation in muscle fibre type composition within the three segments of the muscle. Even when corrected for differences in muscle belly displacement between subjects, the cranial segment was found to have a significantly (p < 0.05) longer contraction time than the two more caudal segments. The results suggest that the gluteus maximus was composed of muscle segments that were physiologically, as well as anatomically, designed to fulfil particular roles during everyday motor tasks. Based upon these results, the MMG technique appears to have considerable utility for the non-invasive assessment of muscle segment contractile properties for both laboratory and clinical applications.
A Unified Perspective on the Dynamics of Axisymmetric Hurricanes and Monsoons
Authors: Wirth Volkmar , Dunkerton Timothy J. 
Published: October 2006

Abstract
This paper provides a unified perspective on the dynamics of hurricane- and monsoonlike vortices by identifying them as specific limiting cases of a more general flow system. This more general system is defined as stationary axisymmetric balanced flow of a stably stratified non-Boussinesq atmosphere on the f plane. The model is based on the primitive equations assuming gradient wind balance in the radial momentum equation. The flow is forced by heating in the vortex center, which is implemented as relaxation toward a specified equilibrium temperature Te. The flow is dissipated through surface friction, and it is assumed to be almost inviscid in the interior. The heating is assumed supercritical, which means that Te does not allow a regular thermal equilibrium solution with zero surface wind, and which gives rise to a cross-vortex secondary circulation. Numerical solutions are obtained using time stepping to a steady state, where at each step the Eliassen secondary circulation is diagnosed as part of the solution strategy.
Reality and regularity of the solution is discussed, putting this work in relation to previous work. Scaling analysis suggests that for a given geometry, essential vortex properties are controlled by the ratio ℱ = αT/cD, where αT is the rate of thermal relaxation and cD quantifies the strength of surface friction for a given surface wind. For large ℱ, the temperature is close to Te and the vortex shows properties that can be associated with a hurricane including strong cyclonic surface winds. On the other hand, for small ℱ, the vortex shows properties that can be associated with a monsoon; that is, the surface winds are small and the secondary circulation keeps the temperature significantly away from Te. The scaling analysis is verified by numerical solutions spanning a wide range of the parameter space. It is shown how the two limiting cases correspond with the respective approximate semianalytical theories presented previously. The results imply an important role of αT for hurricane formation.
On the Tropospheric Response to Anomalous Stratospheric Wave Drag and Radiative Heating
Authors: Thompson David W. J. , Furtado Jason C. , Shepherd Theodore G. 
Published: October 2006

Abstract
Observational and numerical evidence suggest that variability in the extratropical stratospheric circulation has a demonstrable impact on tropospheric variability on intraseasonal time scales. In this study, it is demonstrated that the amplitude of the observed tropospheric response to vacillations in the stratospheric flow is quantitatively similar to the zonal-mean balanced response to the anomalous wave forcing at stratospheric levels. It is further demonstrated that the persistence of the tropospheric response is consistent with the impact of anomalous diabatic heating in the polar stratosphere as stratospheric temperatures relax to climatology.
The results contradict previous studies that suggest that variations in stratospheric wave drag are too weak to account for the attendant changes in the tropospheric flow. However, the results also reveal that stratospheric processes alone cannot account for the observed meridional redistribution of momentum within the troposphere.
Acute inflammation is exacerbated in mice genetically predisposed to a severe protein C deficiency
Authors: Lay Angelina J. , Donahue Deborah , Tsai Meng-Ju , Castellino Francis J. 
Published: October 2006

Abstract
The anticoagulant, activated protein C (aPC), possesses antithrombotic, profibrinolytic, anti-inflammatory, and antiapoptotic properties, and the level of this protein is an important marker of acute inflammatory responses. Although infusion of aPC improves survival in a subset of patients with severe sepsis, evidence as to how aPC decreases mortality in these cases is limited. Because a total deficiency of PC shows complete neonatal lethality, no animal model currently exists to address the mechanistic relationships between very low endogenous aPC levels and inflammatory diseases. Here, we show for the first time that novel genetic dosing of PC strongly correlates with survival outcomes following endotoxin (LPS) challenge in mice. The data provide evidence that very low endogenous levels of PC predispose mice to early-onset disseminated intravascular coagulation, thrombocytopenia, hypotension, organ damage, and reduced survival after LPS challenge. Furthermore, evidence of an exacerbated inflammatory response is observed in very low PC mice but is greatly reduced in wild-type cohorts. Reconstitution of low-PC mice with recombinant human aPC improves hypotension and extends survival after LPS challenge. This study directly links host endogenous levels of PC with various coagulation, inflammation, and hemodynamic end points following a severe acute inflammatory challenge.