bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endothelin receptor selectivity in chronic kidney disease: rationale and review of recent evidence
Authors: Neuhofer W. , Pittrow D. 
Published: March 2009

AbstractEndothelin (ET) is a potent vasoconstrictory peptide with proinflammatory and profibrotic properties that exerts its biological effects through two pharmacologically distinct receptor subtypes, namely ETAand ETB. In addition to its substantial contribution to normal renal function, a large body of evidence suggests that derangement of the renal ET system is involved in the initiation and progression of chronic kidney disease (CKD) in diabetes, hypertension and glomerulonephritis. Thus, the use of ET receptor antagonists (ERAs) may offer potential novel treatment strategies in CKD. Recent literature on the role of the renal ET system in the healthy kidney was reviewed. In addition, an unbiased PubMed search was performed for studies published during the last 5 years that addressed the effects of ERAs in CKD. A particular objective was to extract information regarding whether selective or nonselective ERAs may have therapeutic potential in humans. ET‐1 acts primarily as an autocrine or paracrine factor in the kidney. In normal physiology, ET‐1 promotes diuresis and natriuresis by local production and action through ETBreceptors in the renal medulla. In pathology, ET‐1 mediates vasoconstriction, mesangial‐cell proliferation, extracellular matrix production and inflammation, effects that are primarily conveyed by ETAreceptors. Results obtained in animal models and in humans with the use of ERAs in CKD are encouraging; nevertheless, it is still under debate which receptor subtype should be targeted. According to most studies, selective inhibition of ETAreceptors appears superior compared with nonselective ERAs because this approach does not interfere with the natriuretic, antihypertensive and ET clearance effects of ETBreceptors. Although preliminary data in humans are promising, the potential role of ERAs in patients with CKD and the question of which receptor subtype should be targeted can only be clarified in randomized clinical trials.
Endothelin receptor antagonism and cancer
Authors: Bhalla A. , Haque S. , Taylor I. , Winslet M. , Loizidou M. 
Published: March 2009

AbstractThe endothelin peptides have an important role in the cancer‐stromal interactions that promote tumour growth. Endothelin‐1 (ET‐1), clinically the most investigated endothelin, is a vital agent in the growth and progression of several tumours including prostate, ovarian, colorectal, bladder, breast and lung carcinomas. ET‐1 exerts its effects through the activation of two distinct receptors, ETA and ETB. Once activated, these receptors transmit signals via numerous intracellular signalling pathways. The effects of ET receptor stimulation in cancer cells or cancer‐associated cells include proliferation, resistance to apoptosis, angiogenesis, migration and subsequent invasion. At present, the manipulation of the endothelin axis within the pre‐clinical setting is the subject of intense investigation. Recent studies into ET receptor antagonism have produced interesting results highlighting the fact that these receptors may provide novel targets for a new generation of chemotherapeutic agents in a variety of cancers.
Complementary action of jasmonic acid on salicylic acid in mediating fungal elicitor‐induced flavonol glycoside accumulation of Ginkgo biloba cells
Authors: XU MAOJUN , DONG JUFANG , WANG HUIZHONG , HUANG LUQI 
Published: March 2009

ABSTRACTThe antagonistic action between jasmonic acid (JA) and salicylic acid (SA) in plant defence responses has been well documented. However, their relationship in secondary metabolite production is largely unknown. Here, we report that PB90, a protein elicitor from Phytophthora boehmeriae, triggers JA generation, SA accumulation and flavonol glycoside production of Ginkgo biloba cells. JA inhibitors suppress not only PB90‐triggered JA generation, but also the elicitor‐induced flavonol glycoside production. However, the elicitor can still enhance flavonol glycoside production even though the JA generation is totally inhibited. Over‐expression of SA hydrolase gene NahG not only abolishes SA accumulation, but also suppresses the elicitor‐induced flavonol glycoside production when JA signalling is inhibited. Interestingly, expression of NahG does not inhibit the elicitor‐induced flavonol glycoside accumulation in the absence of JA inhibitors. Moreover, JA levels are significantly enhanced when SA accumulation is impaired in the transgenic cells. Together, the data suggest that both JA and SA are involved in PB90‐induced flavonol glycoside production. Furthermore, we demonstrate that JA signalling might be enhanced to substitute for SA to mediate the elicitor‐induced flavonol glycoside accumulation when SA signalling is impaired, which reveals an unusual complementary relationship between JA and SA in mediating plant secondary metabolite production.
Picking battles wisely: plant behaviour under competition
Authors: NOVOPLANSKY ARIEL 
Published: March 2009

ABSTRACTPlants are limited in their ability to choose their neighbours, but they are able to orchestrate a wide spectrum of rational competitive behaviours that increase their prospects to prevail under various ecological settings. Through the perception of neighbours, plants are able to anticipate probable competitive interactions and modify their competitive behaviours to maximize their long‐term gains. Specifically, plants can minimize competitive encounters byavoidingtheir neighbours; maximize their competitive effects by aggressivelyconfrontingtheir neighbours; ortoleratethe competitive effects of their neighbours. However, the adaptive values of these non‐mutually exclusive options are expected to depend strongly on the plants' evolutionary background and to change dynamically according to their past development, and relative sizes and vigour. Additionally, the magnitude of competitive responsiveness is expected to be positively correlated with the reliability of the environmental information regarding the expected competitive interactions and the expected time left for further plastic modifications. Concurrent competition over external and internal resources and morphogenetic signals may enable some plants to increase their efficiency and external competitive performance by discriminately allocating limited resources to their more promising organs at the expense of failing or less successful organs.
Antagonism between salicylic and abscisic acid reflects early host–pathogen conflict and moulds plant defence responses
Authors: De Torres Zabala Marta , Bennett Mark H. , Truman William H. , Grant Murray R. 
Published: March 2009

SummaryThe importance of phytohormone balance is increasingly recognized as central to the outcome of plant–pathogen interactions. Recently it has been demonstrated that abscisic acid signalling pathways are utilized by the bacterial phytopathogen Pseudomonas syringae to promote pathogenesis. In this study, we examined the dynamics, inter‐relationship and impact of three key acidic phytohormones, salicylic acid, abscisic acid and jasmonic acid, and the bacterial virulence factor, coronatine, during progression of P. syringae infection of Arabidopsis thaliana. We show that levels of SA and ABA, but not JA, appear to play important early roles in determining the outcome of the infection process. SA is required in order to mount a full innate immune responses, while bacterial effectors act rapidly to activate ABA biosynthesis. ABA suppresses inducible innate immune responses by down‐regulating SA biosynthesis and SA‐mediated defences. Mutant analyses indicated that endogenous ABA levels represent an important reservoir that is necessary for effector suppression of plant‐inducible innate defence responses and SA synthesis prior to subsequent pathogen‐induced increases in ABA. Enhanced susceptibility due to loss of SA‐mediated basal resistance is epistatically dominant over acquired resistance due to ABA deficiency, although ABA also contributes to symptom development. We conclude that pathogen‐modulated ABA signalling rapidly antagonizes SA‐mediated defences. We predict that hormonal perturbations, either induced or as a result of environmental stress, have a marked impact on pathological outcomes, and we provide a mechanistic basis for understanding priming events in plant defence.
Neonatal MRI in preterm infants with periventricular leukomalacia and mild disability
Authors: Jinnou Hideo , Kouwaki Masanori , Kiyosawa Syusuke , Yokochi Kenji 
Published: March 2009

AbstractBackground:  The aim of the present study was to describe the neonatal magnetic resonance imaging (MRI) findings of preterm infants with periventricular leukomalacia and mild neurological disability.Methods:  MRI findings at term equivalent were retrospectively investigated in eight preterm infants with mild disability and periventricular leukomalacia diagnosed on MRI in infancy.Results:  Linear, spotted, or macular areas of hyperintensity on T1‐weighted imaging and hypointensity on T2‐weighted imaging were identified in all subjects in the white matter lateral to the body of the lateral ventricle. No cystic lesions were seen. These findings were more widespread and more clearly visualized on T2‐weighted imaging than T1‐weighted imaging.Conclusions:  Linear, spotted, or macular lesions that are hyperintense on T1‐weighted imaging and hypointense on T2‐weighted imaging are possibly compatible with periventricular leukomalacia.
Questionnaire survey on pediatric hypertension in Japan and Korea
Authors: Yim Hyung Eun , Lee Eun Hee , Jang Gi Young , Yoo Kee Hwan , Son Chang Sung , Hong Young Sook , Lee Joo Won , Ito Yuhei , Ikezumi Yohei , Uchiyama Makoto 
Published: March 2009

AbstractBackground:  Hypertension (HTN) is no longer viewed as an adult disease. The purpose of the present study was to understand how hypertensive children are evaluated and managed, by surveying pediatricians in Japan and South Korea.Methods:  A questionnaire was mailed to 109 Japanese (JA) and 159 Korean (KO) pediatric cardiologists, pediatric nephrologists, and other pediatricians.Results:  A total of 127 replies were received (response rate 47%). Most of respondents did not check blood pressure (BP) routinely in outpatient clinics (JA 77%, KO 88%). A mercury sphygmomanometer was the most commonly used method for BP measurements (JA 72%, KO 62%). BP treatment goals were usually set at the 95th percentile for age, gender, and height (JA 47%, KO 54%). More KO used a lower goal in children with primary HTN than JA. KO respondents preferred angiotensin‐converting enzyme inhibitors (ACEI) as initial agents regardless of underlying diseases whereas JA respondents chose various medications, that is, calcium channel blockers, diuretics, and ACEI. For BP monitoring, self‐monitoring was found to be most frequent in both countries (JA 80%, KO 57%). Ambulatory BP monitoring was not frequently utilized in both countries (JA 33% KO 34%).Conclusion:  The current assessment, management and differing trends in pediatric HTN in Japan and Korea have been identified in the present study. Pediatricians should be aware of the growing implications of HTN in children.
The Use of Simple Reparameterizations to Improve the Efficiency of Markov Chain Monte Carlo Estimation for Multilevel Models with Applications to Discrete Time Survival Models
Authors: Browne William J. , Steele Fiona , Golalizadeh Mousa , Green Martin J. 
Published: March 2009

SummaryWe consider the application of Markov chain Monte Carlo (MCMC) estimation methods to random-effects models and in particular the family of discrete time survival models. Survival models can be used in many situations in the medical and social sciences and we illustrate their use through two examples that differ in terms of both substantive area and data structure. A multilevel discrete time survival analysis involves expanding the data set so that the model can be cast as a standard multilevel binary response model. For such models it has been shown that MCMC methods have advantages in terms of reducing estimate bias. However, the data expansion results in very large data sets for which MCMC estimation is often slow and can produce chains that exhibit poor mixing. Any way of improving the mixing will result in both speeding up the methods and more confidence in the estimates that are produced. The MCMC methodological literature is full of alternative algorithms designed to improve mixing of chains and we describe three reparameterization techniques that are easy to implement in available software. We consider two examples of multilevel survival analysis: incidence of mastitis in dairy cattle and contraceptive use dynamics in Indonesia. For each application we show where the reparameterization techniques can be used and assess their performance.
Prediction in Multilevel Generalized Linear Models
Authors: Skrondal Anders , Rabe-Hesketh Sophia 
Published: March 2009

SummaryWe discuss prediction of random effects and of expected responses in multilevel generalized linear models. Prediction of random effects is useful for instance in small area estimation and disease mapping, effectiveness studies and model diagnostics. Prediction of expected responses is useful for planning, model interpretation and diagnostics. For prediction of random effects, we concentrate on empirical Bayes prediction and discuss three different kinds of standard errors; the posterior standard deviation and the marginal prediction error standard deviation (comparative standard errors) and the marginal sampling standard deviation (diagnostic standard error). Analytical expressions are available only for linear models and are provided in an appendix. For other multilevel generalized linear models we present approximations and suggest using parametric bootstrapping to obtain standard errors. We also discuss prediction of expectations of responses or probabilities for a new unit in a hypothetical cluster, or in a new (randomly sampled) cluster or in an existing cluster. The methods are implemented in gllamm and illustrated by applying them to survey data on reading proficiency of children nested in schools. Simulations are used to assess the performance of various predictions and associated standard errors for logistic random-intercept models under a range of conditions.
Hilltopping, leks and female choice in the Carpenter bee Xylocopa (Neoxylocopa) varipuncta
Authors: ALCOCK J. , SMITH A. P. 
Published: March 2009

The mating system of the Carpenter bee, Xylocopa (Neoxylocopa) varipuncta Patton, closely resembles the leks of certain vertebrates. Males defend hovering stations at small creosote bushes on ridgetops in the Sonoran Desert, as well as at large ironwood trees in dry washes. Ridgetops, like washes, may provide orientation guides for dispersing females, channelling potential mates to waiting males. During the height of the two month flight season, both males and females were more concentrated on the ridge than in the wash. Males were particularly densely aggregated at or near two prominent peaks on the study ridge. At times, two or more males occupied the same creosote bush. Females visited hovering males infrequently, and exhibited a high degree of freedom in mate choice, usually rejecting males after a close inspection.The reduction in territorial intolerance exhibited by some males at ridgetop sites may occur: (1) because of the costs of repelling many intruders and (2) because females may choose among males through direct analysis of male phenotype, rather than by selecting a male on the basis of territory position.
A laboratory study of optimal behaviour and the costs of net construction by Polycentropus Havomaculatus (Insecta: Trichoptera: Polycentropodidae)
Authors: DUDGEON DAVID 
Published: March 2009

Metabolic rates of Polycentropus flavomaculatus larvae in a flow‐through respirometer at 15°C were 17 % higher during net spinning than while larvae were resting. The energy content of net silk and caddisfly tissues, obtained by bomb calorimetry, were 23–367 J mgAFDW‐1 and 25–715 J mg AFDW‐1, respectively. Total cost of net construction for an ‘average’ 5th instar larva (2–808 mg dry wt) was 0124 J as silk (75–8 % of total cost) and 0030 J as increased activity over the 293‐minute building period at 15°C.A significant cost jn net building was demonstrated by larvae which were forced to rebuild their nets daily. They lost more weight than larvae which were forced to rebuild every second day; undisturbed (starved) larvae lost least weight. The weight of nets which were rebuilt daily declined over successive constructions, but net allocation (net weight/larval weight) remained rather constant. The major energetic expense of undisturbed larvae was routine metabolism, whilst that of the daily rebuilders was silk synthesis.Feeding regime had a marked influence on net construction, and ad libitum fed larvae built larger nets than those fed every second day; starved larvae built the smallest nets. Food capture was apparently linked to the initiation of construction behaviour and thus a more liberal feeding regime was associated with larger nets.The energy gain (food intake –costs of metabolism and silk synthesis) of ad libitum fed larvae was greater than that of animals fed every second day, and the cost/benefit function for both groups declined throughout the experiment. While each meal was associated with additional net‐spinning costs, over time, the animals tended towards greater energetic economy.Prior feeding regime had no effect on the weight of nets built subsequently; nets were spun without reference to expectation of prey capture. Prior feeding regime had a significant effect on giving‐up time, and those animals with previous experience of high prey capture rates abandoned nets sooner than larvae which had experienced a lower rate of encounter. However, the giving‐up time of all treatment groups (< 50 % given‐up after 30 days) was longer than previously reported for polycentropodids.Polycentropus flavomaculatus larvae have resting metabolic rates lower than those of ‘normal’ poikilotherms and spiders, but similar to those of ant lions. These differences are correlated with modes of food capture, and allow P. flavomaculatus to endure periods of food scarcity.
An analysis of the forces of fighting of the blackbuck (Antilope cervicapra) and the bighorn sheep (Ovis canadensis) and the mechanical design of the horn of bovids
Authors: Kitchener Andrew 
Published: March 2009

The costs and benefits of fighting in bovids are high in terms of injury and reproductive success, respectively. The breakage of a horn would curtail reproductive success permanently. Therefore, the horns of bovids should include sufficient material so that they are strong enough to be unlikely to break in fighting but without being too heavy to carry around. The forces developed during fighting were measured in a computerized analysis of film of blackbuck and bighorn sheep. All possible modes of failure were investigated using a mechanical analysis to see how the horns are most likely to fail.The maximum possible force developed during fighting is 3400 N for the bighorn sheep and 456 N for the blackbuck. Bending stress, shear stress, deflection, strain energy and critical crack lengths were calculated for the horns of these two bovids. Horns are most likely to fail in bending as indicated by safety factors. Most of the force is taken in compression due to the curvature of horns. Shear stresses are insignificant and deflections are negligible during the most forceful encounters.The safety factor in bending of the horn of the bighorn sheep is greater (10) than that of the horn of the blackbuck (3.4) because the forces are probably more variable and unpredictable in the fighting of the former.All of the energy of fighting is absorbed by the body musculature because horns store less than 1% of the energy produced in fighting as strain energy when they bend. Cracks and scratches mustbe more than 60% of the transverse basal dimensions of horns in order for there to be catastrophic failure at the maximum stresses developed during fighting.The horns of the blackbuck and the bighorn sheep appear to be minimum weight structures given the variability of the forces acting on them and are unlikely to break in fighting given the forces calculated from the analyses of films.
Implications of the dental eruption sequence in Barbourofelis (Carnivora, Nimravidae) for the function of upper canines and the duration of parental care in sabretoothed carnivores
Authors: Bryant Harold N. 
Published: March 2009

The eruption of the large deciduous upper canines in the nimravid sabretooth cat Barbourofelis was delayed until after the individual was eating meat. This inference is based primarily on the eruption sequence and dental wear displayed by seven specimens referred to this genus. It indicates that the sabres were not required for feeding and suggests that these teeth were primarily killing devices. The deciduous upper canines in Barbourofelis and the permanent canines in large felids probably erupted at similar stages of dental ontogeny. If the potential for independence from adults occurs with the eruption of canines that were large enough to serve as killing devices, the delayed eruption of the deciduous sabres in nimravids did not necessitate any significant extension to the long period of parental care that is typical of the extant Carnivora.SummaryThe eruption sequence of, and patterns of wear to, the dentition of Barbourofelis demonstrate that juveniles were processing meat before the eruption of the deciduous sabres and thus the upper canines were not necessary for feeding. This supports the view that the sabres were preferentially killing devices; any use of the sabres in dismemberment of the carcass by adults was probably secondary. The transfer of these inferences to felid sabretooths such as Smilodon may be unwise; however, arguments that Smilodon's sabres were inefficient slicing devices (Simpson, 1941), and the patterns of wear on its incisors and cheekteeth (Miller, 1969; Akersten, 1985), suggest that a similar scenario is likely. The marked modifications to the morphology and eruption sequence of the dentition in Barbourofelis may not have resulted in any significant increase in the length of parental care.