bluuebunny/crossref_metadata_2025 huggingface dataset:
A complex biological system: the fly's visual module
Authors: Baptista Murilo S , de Almeida Lirio O.B , Slaets Jan F.W , Köberle Roland , Grebogi Celso
Published: August 2007

Is the characterization of biological systems as
complex systems
in the mathematical sense a fruitful assertion? In this paper we argue in the affirmative, although obviously we do not attempt to confront all the issues raised by this question. We use the fly's visual system as an example and analyse our experimental results of one particular neuron in the fly's visual system from this point of view. We find that the motion-sensitive ‘H1’ neuron, which converts incoming signals into a sequence of identical pulses or ‘spikes’, encodes the information contained in the stimulus into an alphabet composed of a few letters. This encoding occurs on multilayered sets, one of the features attributed to
complex systems
. The conversion of intervals between consecutive occurrences of spikes into an alphabet requires us to construct a
generating partition
. This entails a one-to-one correspondence between sequences of spike intervals and words written in the alphabet. The
alphabet dynamics
is multifractal both with and without stimulus, though the multifractality increases with the stimulus entropy. This is in sharp contrast to models generating independent spike intervals, such as models using Poisson statistics, whose dynamics is monofractal. We embed the support of the probability measure, which describes the distribution of words written in this alphabet, in a two-dimensional space, whose topology can be reproduced by an M-shaped map. This map has positive Lyapunov exponents, indicating a chaotic-like encoding.
Central nervous tissue: an excitable medium. A study using the retinal spreading depression as a tool
Authors: Hanke Wolfgang , de Lima Vera Maura Fernandes
Published: August 2007

According to its physicochemical properties, neuronal tissue, including the central nervous system (CNS) and thus the human brain, is an excitable medium, which consequently exhibits, among other things, self-organization, pattern formation and propagating waves. Furthermore, such systems can be controlled by weak external forces. The spreading depression (SD), a propagating wave of excitation–depression, is such an event, which is additionally linked to a variety of medically important situations, classical migraine being just one example. Especially in retinal tissue, a true part of the CNS, the SD can be observed very easily with the naked eye and by video imaging techniques due to its big intrinsic optical signal.

We have investigated the retinal SD and its control by external physical parameters such as gravity and temperature. Beyond this, especially due to its medical relevance, the control of CNS excitability by pharmacological tools is of specific interest, and we have studied this question in detail using the retinal SD as an experimental tool to collect information about the control of CNS tissue excitability.
Interaction of noise with excitable dynamics
Authors: Santos Gerardo J.Escalera , Rivera M , Escalona J , Parmananda P
Published: August 2007

In this paper, the interaction of noise with excitable dynamics of a three-electrode electrochemical cell is examined. Different scenarios involving both external and internal noise sources are considered. In the case of external noise, aperiodic stochastic resonance and regulation of the noise-induced spiking behaviour are investigated. In the case of internal noise, the interaction of intrinsic electrochemical noise with autonomous nonlinear dynamics is studied. The amplitude of this internal noise, determined by the concentration of chloride ions, is monotonically increased and the provoked dynamics are analysed. Our results indicate that internal noise, similar to its external counterpart, is able to induce regularity in the system response.
Dynamics, bifurcations and chaos in coupled lasers
Authors: Lindberg Åsa Marie , Fordell Thomas , Valling Simo
Published: August 2007

Experiments and numerical modelling on two different class B lasers that are subjected to external optical light injection are presented. This presentation includes ways of measuring the changes in the laser output, how to numerically describe the systems and how to construct diagrams of the dynamical states in the plane frequency detuning between lasers and injection strength. The scenarios for the semiconductor laser include an area of frequency locking and islands of chaotic behaviour embedded in and mixed with periodic doubling regimes. Using a rate equation model, the largest Lyapunov exponent is calculated as a measure of the stability of equilibriums and the amount of chaos in chaotic regimes. In the solid-state laser case, different dynamical regions were clearly observed. The found boundaries were identified experimentally, using an identification method, and numerically, from bifurcation analysis, as Hopf, saddle-node, period-doubling and torus bifurcations.
Synchronization of coupled bistable chaotic systems: experimental study
Authors: Pisarchik Alexander N , Jaimes-Reátegui Rider , García-López J. Hugo
Published: August 2007

We carried out an experimental study of the synchronization of two unidirectionally coupled Rössler-like electronic circuits with two coexisting chaotic attractors. Different stages of synchronization are identified on the route from asynchronous motion to complete synchronization, as the coupling parameter is increased: intermittent asynchronous jumps between coexisting attractors; intermittent anticipating phase synchronization; and generalized synchronization in the form of subharmonic entrainment terminated by complete synchronization. All these regimes are analysed with time-series, power spectra and phase-space plots of the drive and response oscillators. The experimental study implicitly confirms the results of numerical simulations.
Adaptive specialization, conditional plasticity and phylogenetic history in the reproductive cue response systems of birds
Authors: Hahn Thomas P , MacDougall-Shackleton Scott A
Published: August 2007

Appropriately timed integration of breeding into avian annual cycles is critical to both reproductive success and survival. The mechanisms by which birds regulate timing of breeding depend on environmental cue response systems that regulate both when birds do and do not breed. Despite there being multiple possible explanations for birds' abilities to time breeding appropriately in different environments, and for the distribution of different cue response system characteristics among taxa, many studies infer that adaptive specialization of cue response systems has occurred without explicitly considering the alternatives. In this paper, we make explicit three hypotheses concerning the timing of reproduction and distribution of cue response characteristics among taxa: adaptive specialization; conditional plasticity; and phylogenetic history. We emphasize in particular that although conditional plasticity built into avian cue response systems (e.g. differing rates of gonadal development and differing latencies until onset of photorefractoriness) may lead to maladaptive annual cycles in some novel circumstances, this plasticity also can lead to what appear to be adaptively specialized cue response systems if not viewed in a comparative context. We use a comparative approach to account for the distribution of one important feature of avian reproductive cue response systems, photorefractoriness. Analysis of the distribution within songbirds of one criterion for absolute photorefractoriness, the spontaneous regression of the gonads without any decline in photoperiod, reveals that a failure to display this trait probably represents an adaptive specialization to facilitate a flexible reproductive schedule. More finely resolved analysis of both criteria for absolute photorefractoriness (the second being total lack of a reproductive response even to constant light after gonadal regression has occurred) within the cardueline finches not only provides further confirmation of this interpretation, but also indicates that these two criteria for photorefractoriness can be, and have been, uncoupled in some taxa. We suggest that careful comparative studies at different phylogenetic scales will be extremely valuable for distinguishing between adaptive specialization and non-adaptive explanations, such as phylogenetic history as explanations of cue response traits in particular taxa. We also suggest that particular focus on taxa in which individuals may breed on very different photoperiods (latitudes or times of year) in different years should be particularly valuable in identifying the range of environmental conditions across which conditionally plastic cue responses can be adaptive.
DNA based cladograms augment the discovery of a new Ips species from China (Coleoptera: Curculionidae: Scolytinae)
Authors: Cognato Anthony I. , Sun Jiang Hua
Published: August 2007

The implementation of DNA in taxonomic study is in its infancy because the association of the amount and type of nucleotide change with species boundaries has not been fully examined for most taxa. Mitochondrial cytochrome c oxidase I (COI) nucleotide data is currently the most popular molecular marker for delimiting species boundaries and a standard pair‐wise nucleotide divergence between groups of individuals has been suggested for the recognition of new species. It is unlikely that such a standard would be applicable across animal species, but the association of the amount and type of nucleotide change with species boundaries could help with the establishment of a taxon‐specific DNA taxonomy.

This study utilizes DNA data from nuclear and mitochondrial genes to improve the taxonomy of an important forest beetle pest, Ips. Amount and type of nucleotide difference are associated with monophyletic species based on a cladistic analysis of these data. As a result, a new species from China is described for a clade of beetles whose nucleotide differences exceeded the amount of evolutionary change observed within currently recognized species. The COI data are analyzed independently with an expanded taxon data set, including pair‐wise nucleotide differences between recognized sister species. The wide range of average intraspecific pair‐wise nucleotide difference (0–10.0%) suggests limitations to the application of a standard percent nucleotide difference as a means to identify species boundaries. At most, average COI nucleotide intraspecific difference provides an informal guide to identify potential clades that may warrant further systematic investigation.

© The Willi Hennig Society 2007.
Self‐Reported Cannabis Use in Great Britain in 1981
Authors: Mott Joy
Published: August 2007

The 1982 British Crime Survey collected information on self‐reported offending including cannabis use from a large representative sample of the population of Great Britain aged 16 and older. Five per cent of the sample said they had ever used cannabis compared with two per cent of a representative sample of people aged 16–19 in England and Wales interviewed in 1969. While there are some differnces between the present national samples in the proportions saying they had ever used cannabis, more of the 20–34 year olds of both sexes, particularly those who said they had completed their education after the age of 17, than of other sub‐groups in the sample said they had ever used done so. The limitations of national surveys of self‐reported drug use are discussed.
Plasma concentrations of fluticasone propionate and budesonide following inhalation: effect of induced bronchoconstriction
Authors: Mortimer Kevin J. , Tattersfield Anne E. , Tang Yufei , Wu Kai , Lewis Sarah , Hochhaus Gunther , Harrison Tim W.
Published: August 2007

What is already known about this subject

• All inhaled corticosteroids are absorbed into the systemic circulation and hence have the potential to cause adverse systemic effects.

• Plasma drug concentrations following inhalation of 1000 µg fluticasone are considerably lower in people with airflow obstruction than in healthy volunteers but this is not the case for budesonide.

What this study adds

• This is the first study to determine whether changes in airflow obstruction within an individual affect the systemic absorption of inhaled fluticasone and budesonide;

• Plasma concentrations of fluticasone and, to a lesser extent, those of budesonide were lower when the drugs were inhaled following induced bronchoconstriction;

• The lower plasma concentrations of corticosteroids seen when the drugs were inhaled following induced bronchoconstriction is likely to reflect variations that will occur with fluctuations in airway caliber in asthma.

Aims

To determine whether and to what extent bronchoconstriction affects plasma concentrations of fluticasone and budesonide following inhalation.

Methods

Twenty people with mild asthma inhaled 1000 µg fluticasone (Accuhaler®) plus 800 µg budesonide (Turbohaler®) on two visits. On one occasion, prior to drug inhalation, FEV1 was decreased by at least 25% using inhaled methacholine. Plasma drug concentrations were measured for each drug over 5 h and area under the plasma concentration‐time curve (AUC(0,5 h)) compared between visits.

Results

The mean difference in FEV1 prior to drug inhalation on the 2 days was 33%. AUC(0,5 h) values for fluticasone and budesonide were lower by a median of 60% (IQR 36–75) and 29% (IQR 2–44), respectively, when administered following bronchoconstriction; the reduction was greater for fluticasone than for budesonide, P = 0.007.

Conclusions

The lower plasma concentrations of fluticasone and, to a lesser extent, budesonide seen when the drugs were inhaled following induced bronchoconstriction, is likely to reflect variations that will occur with fluctuations in airway caliber in asthma.
Activation of protease‐activated receptor‐2 reduces airways inflammation in experimental allergic asthma
Authors: D'Agostino B. , Roviezzo F. , De Palma R. , Terracciano S. , De Nardo M. , Gallelli L. , Abbate G. F. , D'Aiuto E. , Russo M. , Cirino G. , Rossi F.
Published: August 2007

BackgroundProteinase‐activated receptors (PAR)‐2 are members of the family of G‐protein‐coupled receptors activated by proteases. These receptors are widely expressed in several tissues and in virtually all cells involved in rhinitis and asthma. In particular, proteinases activating PAR‐2 may affect airway functions and play a role in human diseases.

ObjectiveAssessment of the role of PAR‐2 in bronchoconstriction, airway responsiveness and immune response after allergic challenge, in rabbits sensitized to Par j 1, the major allergen ofParietaria judaicapollen.

MethodsEvaluation of antigen challenge in rabbits treated with PAR‐2‐activating peptide (PAR‐2AP) (SLIGRL) or the scrambled peptide LSIGRL or vehicle immediately before allergen exposure measuring airway responsiveness. Characterization of bronchoalveolar lavage (BAL) following histamine challenge and phenotype analysis of cells by flow cytometry and analysis of cytokine production by quantitative PCR.

ResultsPAR‐2AP pre‐treatment, but not the scrambled peptide, was able to significantly inhibit bronchoconstriction, airway hyper‐responsiveness and to modulate the immune response induced by allergic challenge in sensitized rabbits. The phenotype analysis of the cells recovered from BAL showed an increase in RLA‐DR‐positive cells while RTLA‐positive cells were unchanged. IFN‐γ and IL‐2 production were inhibited, with a concomitant increase in IL‐10 of about 10‐fold over the control values.

ConclusionsIn this experimental model, PAR‐2 modulates bronchoconstriction interfering with antigen challenge‐induced immune response in rabbits sensitized and challenged to Par j 1.
Recombinant human luteinizing hormone, lutropin alfa, for the induction of follicular development and pregnancy in profoundly gonadotrophin‐deficient women
Authors: Kaufmann Robert , Dunn Randall , Vaughn Thomas , Hughes Graeme , O’Brien Fanny , Hemsey George , Thomson Barbara , St. L. O'Dea Louis
Published: August 2007

Objective  To provide evidence of efficacy and safety for use of lutropin alfa in inducing follicular development and pregnancy in hypogonadotrophic hypogonadal women with profound gonadotrophin deficiency.

Design  An open‐label, noncomparative extension of a randomized, double‐blind, placebo‐controlled study

Patients  A total of 31 hypogonadotrophic hypogonadal women with profound gonadotrophin deficiency in 23 medical centres in four countries were studied.

Interventions  Lutropin alfa 75 IU and follitropin alfa (75–225 IU), individually based on each patient's response as is consistent with usual medical practice.

Measurements  Follicular development as defined by (i) at least one follicle ≥ 17 mm; (ii) preovulatory serum oestradiol level ≥ 109 pg/ml on the day of hCG administration; and (iii) midluteal phase P4 level ≥ 7·9 ng/ml. Pregnancy and over‐response leading to cycle cancellation were considered treatment successes. Pregnancy rates were assessed.

Results  In a total of 54 cycles, 27 of 31 (87·1%) profoundly gonadotrophin‐deficient patients achieved follicular development within three cycles. Twenty of 27 patients (74·1%) who achieved follicular development and received hCG became pregnant; 16 (59·3%) continued to clinical pregnancy. One patient was hospitalized for severe ovarian hyperstimulation syndrome. Lutropin alfa was well tolerated.

Conclusions  Coadministration of lutropin alfa 75 IU and follitropin alfa is safe and effective in inducing follicular development and pregnancy in hypogonadotrophic hypogonadal women with profound gonadotrophin deficiency in a setting consistent with established medical practice.
Pillow lavas as a habitat for microbial life
Authors: Furnes Harald , Banerjee Neil R. , Staudigel Hubert , Muehlenbachs Karlis
Published: August 2007

The upper oceanic crust consists predominantly of pillow lavas that, soon after their eruption, are colonized by microbes when the ambient temperature ameliorates. During the process of microbial interaction with the glassy rims of pillows several types of bio‐traces are generated, of which micro‐textures are the most spectacular. Microbial textures are most useful for mapping the depth of the oceanic biosphere, and in the search for the earliest life on Earth.
Phytoliths in palaeoecology
Authors: Thorn Vanessa
Published: August 2007

With increasing interest in climate change and other issues associated with the history of the environment and anthropogenic evolution there is an ongoing requirement to investigate the Earth's natural systems. A key approach is for scientists to look back into geological time, perhaps millions of years, to see how the world has reacted to natural climatic changes in the past. Using evidence from the fossil record, fluctuations in palaeoclimate can be assessed with reference to changes in global floral and faunal patterns. Phytoliths, Greek for ‘plant stones’, is a fossil group that is being increasingly utilized in the understanding of past climates and environments.
Intrauterine growth standards in a developing country: a study of singleton livebirths at 28–42 weeks' gestation
Authors: Yunis Khalid A. , Khawaja Marwan , Beydoun Hind , Nassif Yolla , Khogali Mustafa , Tamim Hala ,   for the National Collaborative Perinatal Neonatal Network (NCPNN)
Published: August 2007

This study aimed to develop fetal growth charts for the population of Greater Beirut, Lebanon, and compare them with previously established references. A survey of consecutive singleton livebirths admitted to normal nurseries and neonatal intensive care units of major hospitals, through the database project of the National Collaborative Perinatal Neonatal Network was used as a design. The study was conducted in nine major healthcare institutions serving the population of Beirut and its suburbs. A total of 24 767 singleton livebirths delivered between 28 and 42 weeks' gestation, with known data on gender, gestational age and anthropometric characteristics were recorded between 1 April 1999 and 31 March 2002. Growth charts were developed by plotting birthweight, length and head circumference percentiles against gestational age for male and female infants separately.

Overall, 1348 (5.4%) pregnancies were delivered before 37 weeks' gestation and 1227 (4.9%) were low birthweight. Male infants were delivered slightly earlier than their female counterparts and the mean birthweight, length and head circumference were consistently higher in males. A total of 2247 (9.1%) infants were small‐for‐gestational‐age, with a male‐to‐female sex ratio of 1.03. Using previously established growth references that overestimated small‐for‐gestational‐age prevalence resulted in a greater proportion of false positives. The opposite was true for growth references that underestimated small‐for‐gestational‐age prevalence.

The current growth charts present useful tools for assessing the general health status of newborn infants delivered at sea level in the urban areas of Lebanon and other East Mediterranean countries.
Effect of smoking and alcohol use during pregnancy on the occurrence of low birthweight in a farming region in South Africa
Authors: Jackson Debra J. , Batiste Elize , Rendall‐Mkosi Kirstie
Published: August 2007

The aim of this case–control study was to determine the risk factors for low birthweight in a farming region in South Africa, with particular attention to maternal alcohol use and smoking, both independently and in combination. Data collection was via structured postpartum interviews and review of antenatal and delivery records. The study setting was a regional referral hospital in a farming region. The study subjects were 200 infants with birthweight <2500g (cases) and 200 unmatched control infants of normal weight born during the same period as the cases. The outcome measure was low birthweight, i.e. infant birthweight <2500 g.

Results showed the contribution of term low birthweight (as a measure of intrauterine growth retardation) to the total low‐birthweight incidence was almost 50%, indicating a substantial intrauterine growth retardation component in this population. Sociodemographic factors were not as predictive of low birthweight in this predominantly low income population. Smoking (adjusted OR 2.67, [95% CI 1.69, 4.20]) was the strongest life style‐related predictor of low birthweight. The alcohol low‐birthweight relationship was not significant when adjusted for smoking status (crude OR 2.15, [95% CI 1.37, 3.39]; adjusted OR 1.32, [95% CI 0.80, 2.20]). However, there appeared to be an interaction with combined use of these two substances during pregnancy that increased the risk of low birthweight (adjusted OR increased to 4.24, [95% CI 1.01, 17.76]. It is clear that life style factors such as smoking and drinking are contributing to the occurrence of low birthweight in the target region. A comprehensive health promotion programme needs to be implemented as an integral part of antenatal and family planning services, to reduce smoking and drinking by women in this community.
Growth outcomes for Australian Aboriginal children aged 11 years who were born with intrauterine growth retardation at term gestation
Authors: Sayers Susan , Mackerras Dorothy , Halpin Stephen , Singh Gurmeet
Published: August 2007

Long‐term poor growth outcomes are well documented for intrauterine growth‐retarded babies (IUGR) in developed populations but there is a paucity of IUGR studies from disadvantaged populations where the greatest burden of IUGR occurs. Using a Northern Territory, Aboriginal cohort recruited at birth and followed up at a mean age of 11.4 years, comparisons of body size were made between children born at term who had been IUGR (n = 121) and those non‐IUGR (n = 341), and between those IUGR babies who had an appropriate ponderal index at birth (n = 72) and those with a low ponderal index (n = 49).

Compared with non‐IUGR children, at follow‐up the IUGR children were almost 2 cm shorter (P = 0.10), 4 kg lighter (P < 0.01) and their head circumferences were almost a 1 cm smaller (P < 0.01). For the 121 term IUGR children, there were no significant differences in growth outcomes according to ponderal index measures at birth. These findings from an Australian Aboriginal sample are consistent with other comparisons of IUGR and non‐IUGR children in developed populations and suggest there may be no additional effects of IUGR on growth in childhood for disadvantaged populations similar to the Aboriginal population in the Northern Territory.
Of old and new diseases: genetics of pituitary ACTH excess (Cushing) and deficiency
Authors: Drouin J , Bilodeau S , Vallette S
Published: August 2007

The pituitary gland orchestrates our endocrine environment: it produces hormones in response to hypothalamic factors that integrate neural inputs and its activity is balanced by the feedback action of peripheral hormones. Disruption of this equilibrium has severe consequences that affect multiple systems and may be fatal. Genetic analysis of pituitary function led to discovery of critical transcription factors that cause hormone deficiencies when mis‐expressed. This review will summarize recent findings that led to the first complete clinical description of inherited, isolated corticotropin (ACTH) deficiency (IAD) and to the first molecular mechanism for excessive ACTH production in Cushing’s disease. Indeed, mutations in TPIT, a positive or negative regulator of cell fates for different pituitary lineages, cause neonatal IAD, a condition considered anecdotic before discovery of this transcription factor. Cushing’s disease is caused by corticotroph adenomas that produce excess ACTH as a result of resistance to glucocorticoids (Gc). Molecular investigation of the normal mechanism of Gc feedback led to identification of two essential proteins for pro‐opiomelanocortin repression that are often mis‐expressed in corticotroph adenomas thus providing a molecular explanation for Gc resistance. These two proteins, Brg1 and histone deacetylase 2 (HDAC2), are involved in chromatin remodeling and may also participate in the tumorigenic process, as Brg1 is a tumor suppressor. These recent advances have provided improved diagnosis and opened new perspectives for patient management and therapies.
Effects of UV‐B radiation on seed yield of Glycine max and an assessment of F1 generation progeny for carryover effects
Authors: Chimphango Samson B.M. , Brown Carly F. , Musil Charles F. , Dakora Felix D.
Published: August 2007

Glycine max (L.) Merr plants were grown outdoors in potted sand exposed to elevated ultraviolet‐B (UV‐B) radiation provided by filtered fluorescent lamps to determine the effects of UV‐B on seed yield and UV‐B‐induced carryover effects in the F1 generation. Increased UV‐B radiation had no detectable effects on reproductive parameters except for a reduction on seed number per plant and an increase in the number of unseeded pods per plant and dry weight of unseeded pods per plant in the field supplemental UV‐B experiment. Studies on carryover effects in the greenhouse progeny growth trial also showed no effect of parental treatment with UV‐B on biomass production, and most symbiotic‐N traits and plant metabolite measured. However, the concentrations of N in nodules and starch in roots were significantly increased in the F1 generation progeny from elevated UV‐B radiation relative to their F1 counterparts from ambient radiation. Assessing the effects of seed size on plant growth and symbiotic function in the F1 progeny showed that total biomass, dry matter yield of individual organs (leaves, stems, roots and nodules), total plant N and fixed‐N rose with increasing seed size. Seed concentration of flavonoids was also enhanced with increasing seed size. These findings suggest that subtle changes did occur in the F1 generation progeny of parental plants exposed to elevated UV‐B with potential to accumulate with further exposure to elevated UV‐B radiation.
Functional characterization of AP3, SOC1 and WUS homologues from citrus (Citrus sinensis)
Authors: Tan Fui‐Ching , Swain Stephen M.
Published: August 2007

Flowering and flower formation are defining features of angiosperms and the control of these developmental processes involves a common repertoire of genes which are shared among different species of flowering plants. These genes were first identified using various homeotic and flowering time mutants of Arabidopsis and snapdragon, and homologous genes have subsequently been isolated from a wide range of different plant species based on the conservation of protein sequence and function. Using degenerate reverse‐transcriptase polymerase chain reaction, we have isolated one APETALA3‐like (CitMADS8) and two SOC1 (SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1)‐like (CsSL1 and CsSL2) homologues from sweet orange (Citrus sinensis L.). Although the translated amino acid sequence of CitMADS8 shares many similarities with other higher plant APETALA3 proteins, CitMADS8 fails to complement the floral organ identity defects of the Arabidopsis ap3‐3 mutant. By contrast, the two citrus SOC1‐like genes, particularly CsSL1, are able to shorten the time taken to flower in the Arabidopsis wild‐type ecotypes Columbia and C24, and functionally complement the late flowering phenotype of the soc1 mutant, essentially performing the endogenous function of Arabidopsis SOC1. Once flowering has commenced, interactions between specific flowering genes and a gene required for meristem maintenance, WUSCHEL, ensure that the Arabidopsis flower is a determinate structure with four whorls. We have isolated a citrus WUSCHEL homologue (CsWUS) that is capable of restoring most of the meristem function to the shoots and flowers of the Arabidopsis wus‐1 mutant, implying that CsWUS is the functional equivalent of Arabidopsis WUSCHEL.
Temperature‐dependent post‐diapause development and prediction of spring emergence of the pine needle gall midge (Dipt., Cecidomyiidae)
Authors: Son Y. , Lee J.‐H. , Chung Y.‐J.
Published: August 2007

Abstract:  We determined the influence of temperature on post‐diapause development of overwintered Thecodiplosis japonensis Uchida et Inouye (Dipt., Cecidomyiidae) under various treatments (12, 15, 18, 21, 24, 27 and 30°C) in an effort to predict its spring emergence. Survival and developmental period for the overwintered larvae and pupae were significantly influenced by temperature. Linear and nonlinear regression models quantitatively described temperature‐dependent development and survival of T. japonensis. The survival models exhibited right‐skewed bell shape patterns for all stages, indicating a more detrimental impact on survival at high temperatures. Theoretical optimum temperatures with highest survival were 22.3, 24.0 and 24.0°C for the overwintered larvae, pupae and total post‐diapause development (the larvae to adults) respectively. Pupal mortality was higher at all temperatures than larval mortality and the suitable range of temperature for pupae was narrower than that of larvae. The nonlinear Briere model estimated that optimum temperatures with the fastest development were 29.1°C for larvae, 27.6°C for pupae and 27.0°C for larvae to adults. In a linear model, the lower threshold temperatures were 5.1, 7.1 and 5.9°C for larvae, pupae, and larvae to adults respectively. A predictive degree‐day model was developed using trap catches of T. japonensis adult emergence during 1991–1995. The model accounted for 84.6% of year‐to‐year variation in adult emergence and predicted accurately the median emergence time in 1996.
Spatio‐temporal Development of Pea Root Rot Disease through Secondary Infections during a Crop Cycle
Authors: Willocquet L. , Jumel S. , Lemarchand E.
Published: August 2007

Spatio‐temporal development of pea root rot was experimentally characterized. Experiments performed under controlled conditions with trap plants located at varying distances from a diseased source plant indicated that disease spread from a diseased plant to a healthy one was generally below 15 cm. A field experiment was conducted to measure disease spread gradients and the rate of secondary infection at two planting densities, 70 and 140 plants/m2. Relationships between plant and root disease incidences, and between root disease incidence and root disease severity indicated a strong disease intensification both within and between diseased plants. Measurement of disease gradients indicated that disease did not spread farther than 10 cm from the diseased source plant, i.e. one and two plants away along a row at low and high planting densities respectively. Disease did not spread to neighbouring rows, located 15 cm away. Rates of secondary infection over 14‐day periods ranged between zero (no disease increase) and 0.35 plant/plant/day, and was in general larger in high‐density plots than in low‐density plots. Implications of the results for disease management are discussed.
Involvement of Hydrogen Peroxide, Peroxidase and Superoxide Dismutase in Response of Medicago truncatula Lines Differing in Susceptibility to Phoma medicaginis Infection
Authors: Djebali N. , Mhadhbi H. , Jacquet C. , Huguet T. , Aouani M. E.
Published: August 2007

This study was undertaken to assess the involvement of hydrogen peroxide (H2O2), peroxidase (POX; EC 1.11.1.7) and superoxide dismutase (SOD; EC 1.15.1.1) in Medicago truncatula in relation with susceptibility to Phoma medicaginis infection. Several M. truncatula lines were studied in terms of their response to P. medicaginis infection. Fifteen days after inoculation (dai), differences in susceptibility were found. DZA45.5 was the least susceptible line and F83005.5 was the most susceptible line. Microscopic analysis of fungal development was performed in inoculated detached leaves of the DZA45.5 and F83005.5 lines. No significant difference was observed in events from conidia germination to penetration. Differences became apparent during the colonization process as the pathogen was able to sporulate rapidly increasing its concentration on the tissue of F83005.5 in comparison with DZA45.5. To characterize the susceptibility of the two lines, histochemical detection of H2O2 was made in detached leaves. H2O2 detection showed an early accumulation of this component in cells of DZA45.5 at 1 dai. However, H2O2 was detected in few, if any, cells in the tissues of the most susceptible line, F83005.5. The activity of POX and SOD were determined spectrophotometrically in leaves of intact inoculated plants of both lines. Phoma medicaginis inoculation of DZA45.5 and F83005.5 did not affect POX activity level in leaves when compared with control uninoculated plants. SOD activity showed a significant decrease in F83005.5 and DZA45.5 leaves at 4 dai and 9 dai, respectively, in comparison with control plants. In control plants POX activity was significantly higher in the least susceptible line DZA45.5 in comparison with F83005.5. Early and higher production of H2O2 and elevated basal POX activity in cells of the least susceptible line, DZA45.5 could explain its ability to be less favourable to the colonization and reproduction of P. medicaginis in comparison with the most susceptible line, F83005.5.
Morphological and Pathological Variability in Rice Isolates of Rhizoctonia solani and Molecular Analysis of their Genetic Variability
Authors: Guleria S. , Aggarwal R. , Thind T. S. , Sharma T. R.
Published: August 2007

Nineteen isolates of Rhizoctonia solani collected from different rice varieties grown in various regions of Punjab were studied for their morphological and pathological characterization. Majority of the isolates were fast growing with raised and fluffy colonies and hyphal width of 9.6 μm while four exhibited moderate growth rate. Colony colour in all except two isolates was light yellowish brown. While sclerotial number per 5.0 mm culture disc of the test isolates ranged between 2.1 and 11.2 mm, their size varied between 1.31 and 2.08 mm. Sclerotial colour in all except two isolates was dark brown and most of these were found scattered in the colony. There was no relationship between morphologically similar isolates and their pathogenic behaviour. Majority of the isolates produced lesion length between 45.6 and 58.2 mm on detached rice leaves (cv. PR116). Molecular characterization of genetic diversity in the test isolates was studied by using 10 inter simple sequence repeats (ISSR) and eight random amplified polymorphic DNA (RAPD) markers. The size of amplified DNA bands ranged from 0.25–3.0 to 0.5–4.0 kb with ISSR and RAPD markers, respectively. Combined data set of 155 DNA markers were analysed with UPGMA resulting five clusters with 49–89% genetic similarity. Most of the isolates showed grouping specific to the host variety. Out of these two types of DNA markers, RAPD markers were able to detect more genetic variability when compared to ISSR markers.
β2‐ADRENOCEPTOR POLYMORPHISMS AND OBSTRUCTIVE AIRWAY DISEASES: IMPORTANT ISSUES OF STUDY DESIGN
Authors: Yang Ian A , Ng Taria , Molenaar Peter , Fong Kwun M
Published: August 2007

Asthma and chronic obstructive pulmonary disease (COPD) are chronic airway diseases characterized by airflow obstruction. The β2‐adrenoceptor mediates bronchodilatation in response to exogenous and endogenous β‐adrenoceptor agonists.

Single nucleotide polymorphisms in the β2‐adrenoceptor gene (ADRB2) cause amino acid changes (e.g. Arg16Gly, Gln27Glu) that potentially alter receptor function. Recently, a large cohort study found no association between asthma susceptibility and β2‐adrenoceptor polymorphisms. In contrast, asthma phenotypes, such as asthma severity and bronchial hyperresponsiveness, have been associated with β2‐adrenoceptor polymorphisms. Of importance to asthma management, coding region polymorphisms may alter the response to short‐acting and long‐acting β‐adrenoceptor agonists, which are commonly prescribed asthma treatments.

Optimizing study design would enhance the robustness of genetic association studies of ADRB2 polymorphisms in airway diseases. Characteristics of high‐quality studies include suitable study design and subject selection, optimal study of polymorphisms and haplotypes, disease outcomes of relevance, adequate sample size, adjustment for confounding factors, supportive functional data and appropriate analysis, interpretation and replication. Enhancing these study design factors will provide high‐quality evidence regarding the biological and clinical importance of β2‐adrenoceptor pharmacogenomics in asthma and COPD.
RENAL FUNCTIONAL RESPONSES TO ISCHAEMIA–REPERFUSION INJURY IN NORMOTENSIVE AND HYPERTENSIVE RATS FOLLOWING NON‐SELECTIVE AND SELECTIVE CYCLO‐OXYGENASE INHIBITION WITH NITRIC OXIDE DONATION
Authors: Knight Sarah , Johns Edward J
Published: August 2007

Acute renal failure develops as a result of periods of renal ischaemia during cardiovascular surgery or hypovolaemic shock. The present study investigated the importance of endogenous prostaglandin production and nitric oxide (NO) in the renal haemodynamic and excretory responses to ischaemia–reperfusion both normally and in the hypertensive state by chronic administration of cyclo‐oxygenase (COX) inhibitors.

Male Wistar and stroke‐prone spontaneously hypertensive rats (SHRSP) were subjected to 30 min renal ischaemia and 2 h reperfusion following 7 day treatment with vehicle, aspirin, NO–aspirin or celecoxib.

Renal blood flow was higher in the SHRSP treatment groups. Renal ischaemia increased blood pressure in all Wistar groups except that given aspirin, had no effect in the SHRSP and did not change renal blood flow in any group. Glomerular filtration rate was reduced throughout the reperfusion period in both rat strains. The postischaemic diuresis in the Wistar was enhanced by COX‐2 inhibition, but not by aspirin or NO–aspirin. Urine flow increased in SHRSP during the postischaemic period, which was blunted by aspirin and NO–aspirin, but not by celecoxib. There was a postischaemic increase in fractional sodium excretion, the magnitude of which was unaltered by any drug in the Wistar rats, but was blunted by aspirin, NO–aspirin and celecoxib in SHRSP.

These results suggest that products of COX activity contribute to the renal responses to ischaemia–reperfusion injury, but in different ways, in SHRSP, which may reflect variations in renal prostaglandin and NO production in the hypertensive state.
Two steps forward, one step back: advance care planning, Australian regulatory frameworks and the Australian Medical Association
Authors: Parker M , Stewart C. , Willmott L. , Cartwright C.
Published: August 2007

The Australian Medical Association has recently adopted a policy position concerning advance care planning, which is generally supportive of extending patient self‐determination beyond the loss of decision‐making capacity. It calls for uniform national legislation for legally enforceable advance health directives (AHD), and statutory protection for practitioners who comply with valid AHD, or who do not comply on several grounds. Analysis of the grounds for non‐compliance indicate that they undermine patient autonomy, and aspects of the policy are inconsistent with current common law and statutory regimes that allow an adult to complete a legally binding AHD. The policy therefore threatens the patient self‐determination, which it endorses, and places doctors who participate in advance care planning at legal risk.
Failure to weigh patients in hospital: a medication safety risk
Authors: Hilmer S. N. , Rangiah C. , Bajorek B. V. , Shenfield G. M.
Published: August 2007

Often patients are not weighed in hospital. Failure to weigh patients prescribed renally excreted drugs may correlate to adverse drug events. We carried out a cross‐sectional study of patients prescribed common renally excreted drugs (heparin, enoxaparin and gentamicin), admitted to two wards at Royal North Shore Hospital, Sydney over 3 months. Of all patients surveyed, 28% (22/78) in the orthopaedic ward and 22% (27/124) in the medical ward were weighed. Among those prescribed therapeutic doses of the study drugs, 25% (3/12) in the orthopaedic ward and 27% (7/26) in the medical ward were weighed. Patients prescribed therapeutic anticoagulation who were not weighed experienced more haemorrhagic complications than patients who were weighed (P = 0.03). Patients prescribed renally excreted drugs in hospital are frequently not weighed. This is associated with reduced medication safety.
Angioedema, lymphoproliferative disorder and angiotensin‐converting enzyme inhibitors: masking of diagnosis by corticosteroids
Authors: Hissaria P. , Lim S.‐W. , Hui C.‐H. , Gillis D. , Kette F. , Smith W.
Published: August 2007

Angioedema is a relatively common clinical disorder. Although most cases are idiopathic, the use of angiotensin‐converting enzyme inhibitors is a well recognized cause of angioedema and a further rare but important diagnostic consideration is acquired C1 inhibitor deficiency. We discuss the diagnosis of C1 inhibitor deficiency in angioedema, with reference to a case in which the diagnosis was initially masked by the use of corticosteroids, which normalized the C1 inhibitor level.
Assessment of clinical performance: gathering evidence
Authors: Wilkinson T. J.
Published: August 2007

The focus of assessment of clinical performance has moved from over‐reliance on individual tools to constructing a coherent assessment programme. The purpose of such an assessment programme is to gather high‐quality evidence to make well‐informed decisions. This requires clarity on the decisions to be made and an ability to gather a sufficient amount of high‐quality data. The assessment programme should be aligned to doing the job well so that a successful assessment result reflects what is valued. A variety of assessments over a variety of times, matched against the areas of interest and value, enhances both reliability and validity. Workplace‐based assessment tools can complement centralized assessment tools. Multiple snapshots, even if some are not totally in focus, give a better picture than one poorly aimed photograph.
Protective effect of acetyl‐l‐carnitine on the apoptotic pathway of peripheral neuropathy
Authors: Di Cesare Mannelli Lorenzo , Ghelardini C. , Calvani M. , Nicolai R. , Mosconi L. , Vivoli E. , Pacini A. , Bartolini A.
Published: August 2007

Peripheral neuropathies are widespread disorders induced by autoimmune diseases, drug or toxin exposure, infections, metabolic insults or trauma. Nerve damage may cause muscle weakness, altered functionalities and sensitivity, and a chronic pain syndrome characterized by allodynia and hyperalgesia. Pathophysiological mechanisms related to neuropathic disease are associated with mitochondrial dysfunctions that lead to the activation of the apoptotic cascade. In a model of peripheral neuropathy, obtained by the loose ligation of the rat sciatic nerve (CCI), we describe a nerve apoptotic state that encompasses the release of cytochrome C in the cytosol, the activation of caspase 3, and the fragmentation of the genome. Animal treatment with acetyl‐l‐carnitine (ALCAR), but not with l‐carnitine (L‐Carn) or Gabapentin, prevents apoptosis induction. ALCAR reduces cytosolic cytochrome C and caspase 3 active fragments expression in a significant manner with respect to saline treatment. Accordingly, ALCAR treatment impairs caspase 3 protease activity, as demonstrated by reduced levels of cleaved PARP. Finally, ALCAR decreases the number of piknotic nuclei. This protection correlates with the induction of X‐linked inhibitor apoptosis protein (XIAP). Taken together these results show that CCI is a valuable model to investigate neuropathies‐related apoptosis phenomena and that ALCAR is able to prevent regulated cell death in the damaged sciatic nerve.
Spatially correlated recruitment of a marine predator and its prey shapes the large‐scale pattern of density‐dependent prey mortality
Authors: White J. Wilson
Published: August 2007

Patterns of predator dispersal can be critical to the dynamics of prey metapopulations. In marine systems, oceanic currents may shape the dispersal of planktonic larvae of both predators and prey, producing spatial correlations in the recruitment of both species and distinctive geographic patterns of prey mortality. I examined the potential for this phenomenon in two fishes, a wrasse and its grouper predator, at a Caribbean island where the near‐shore oceanographic regime produces a temporally consistent spatial pattern of fish recruitment. I found that recruitment and adult abundance of groupers were spatially correlated with recruitment of wrasse prey. Furthermore, the local abundance of predators strongly affected the nature of density‐dependent prey mortality. At sites with few predators, wrasse mortality was inversely density‐dependent, while mortality was positively density‐dependent at sites with higher predator densities. This phenomenon could be important to the dynamics of any metacommunity in which physical forces produce correlated dispersal.
Improving the prognosis of patients after radical cystectomy. Part II: the role of perioperative chemotherapy
Authors: Suttmann Henrik , Kamradt Jörn , Lehmann Jan , Stöckle Michael
Published: August 2007

In this review we analyse the current status of perioperative systemic chemotherapy in the treatment of transitional cell carcinoma (TCC) of the bladder; instead of summarizing each neoadjuvant or adjuvant clinical trial we focus on the advantages and disadvantages of both strategies on the basis of theoretical considerations, and outline a rationale for a better design of future studies to confirm the efficacy of perioperative chemotherapy in TCC.