bluuebunny/crossref_metadata_2025 huggingface dataset:
Speed of synchronization in complex networks of neural oscillators: Analytic results based on Random Matrix Theory
Authors: Timme Marc , Geisel Theo , Wolf Fred
Published: April 2006

We analyze the dynamics of networks of spiking neural oscillators. First, we present an exact linear stability theory of the synchronous state for networks of arbitrary connectivity. For general neuron rise functions, stability is determined by multiple operators, for which standard analysis is not suitable. We describe a general nonstandard solution to the multioperator problem. Subsequently, we derive a class of neuronal rise functions for which all stability operators become degenerate and standard eigenvalue analysis becomes a suitable tool. Interestingly, this class is found to consist of networks of leaky integrate-and-fire neurons. For random networks of inhibitory integrate-and-fire neurons, we then develop an analytical approach, based on the theory of random matrices, to precisely determine the eigenvalue distributions of the stability operators. This yields the asymptotic relaxation time for perturbations to the synchronous state which provides the characteristic time scale on which neurons can coordinate their activity in such networks. For networks with finite in-degree, i.e., finite number of presynaptic inputs per neuron, we find a speed limit to coordinating spiking activity. Even with arbitrarily strong interaction strengths neurons cannot synchronize faster than at a certain maximal speed determined by the typical in-degree.
Synchronization in complex networks with a modular structure
Authors: Park Kwangho , Lai Ying-Cheng , Gupte Saurabh , Kim Jong-Won
Published: April 2006

Networks with a community (or modular) structure arise in social and biological sciences. In such a network individuals tend to form local communities, each having dense internal connections. The linkage among the communities is, however, much more sparse. The dynamics on modular networks, for instance synchronization, may be of great social or biological interest. (Here by synchronization we mean some synchronous behavior among the nodes in the network, not, for example, partially synchronous behavior in the network or the synchronizability of the network with some external dynamics.) By using a recent theoretical framework, the master-stability approach originally introduced by Pecora and Carroll in the context of synchronization in coupled nonlinear oscillators, we address synchronization in complex modular networks. We use a prototype model and develop scaling relations for the network synchronizability with respect to variations of some key network structural parameters. Our results indicate that random, long-range links among distant modules is the key to synchronization. As an application we suggest a viable strategy to achieve synchronous behavior in social networks.
Synchronizing weighted complex networks
Authors: Chavez M. , Hwang D.-U. , Amann A. , Boccaletti S.
Published: April 2006

Real networks often consist of local units, which interact with each other via asymmetric and heterogeneous connections. In this work, we explore the constructive role played by such a directed and weighted wiring for the synchronization of networks of coupled dynamical systems. The stability condition for the synchronous state is obtained from the spectrum of the respective coupling matrices. In particular, we consider a coupling scheme in which the relative importance of a link depends on the number of shortest paths through it. We illustrate our findings for networks with different topologies: scale free, small world, and random wirings.
Time-dependent alignment of molecules trapped in octahedral crystal fields
Authors: Kiljunen Toni , Schmidt Burkhard , Schwentner Nikolaus
Published: April 2006

The hindered rotational states of molecules confined in crystal fields of octahedral symmetry, and their time-dependent alignment obtained by pulsed nonresonant laser fields, are studied computationally. The control over the molecular axis direction is discussed based on the evolution of the rotational wave packet generated in the cubic crystal-field potential. The alignment degree obtained in a cooperative case, where the alignment field is applied in a favorable crystal-field direction, or in a competitive direction, where the crystal field has a saddle point, is presented. The investigation is divided into two time regimes where the pulse duration is either ultrashort, leading to nonadiabatic dynamics, or long with respect to period of molecular libration, which leads to synchronous alignment due to nearly adiabatic following. The results are contrasted to existing gas phase studies. In particular, the irregularity of the crystal-field energies leads to persistent interference patterns in the alignment signals. The use of nonadiabatic alignment for interrogation of crystal-field energetics and the use of adiabatic alignment for directional control of molecular dynamics in solids are proposed as practical applications.
Wettability patterning of hydroxyapatite nanobioceramics induced by surface potential modification
Authors: Aronov D. , Rosenman G. , Karlov A. , Shashkin A.
Published: April 2006

Hydroxyapatite is known as a substrate for effective adhesion of various biological cells and bacteria as well implantable biomimetic material replacing defective bone tissues. It is found that low energy electron irradiation induces its strong surface potential variation and gives rise to pronounced wettability modification. The found electron-modulation method of the hydroxyapatite wettability enables both wettability switching and its microscopic patterning, which may be used for fabrication of spatially arrayed hydroxyapatite for biological cells immobilization, gene transfer, etc.
Physiological and cytological response of salt-tolerant and non-tolerant barley to salinity during germination and early growth
Authors: Tajbakhsh M. , Zhou M. X. , Chen Z. H. , Mendham N. J.
Published: April 2006

Seven barley cultivars (Franklin, Gairdner, YU6472, Numar, CM72, ZND3 and YUQS) were evaluated for NaCl tolerance in relation to physiological and cytological responses during germination. Standard germination techniques were employed using blotting paper saturated with different NaCl solutions (0, –0.3, –0.6, –0.9, –1.2, –1.5 or –1.8 MPa) at 20°C. The results showed significant differences among varieties for germination percentage, frequency of abnormal seedlings, and Na+, K+ uptake. Of the 7 barley cultivars, CM72 was similar in salt tolerance to Numar, while YUQS and ZND3 were the most sensitive to high salinity. The tolerant cultivars showed much higher germination percentage under salinity stress than susceptible varieties. Both CM72 and Numar maintained more than 90% germination at –1.2 MPa osmotic potential while YUQS and ZND3 had only 57% germination at the same level of salinity. The tolerant varieties also showed shorter mean germination time at low osmotic potential. The start of the first mitosis was delayed, while both the frequencies of aberrant anaphases at the first cell divisions, and the numbers of abnormal seedlings were increased in higher salt concentrations. During the seedling stage, tolerant varieties showed significantly higher K+ concentrations, lower Na+ concentrations, lower Na+/K+ ratio and higher photosynthetic rate than susceptible varieties under salinity stress. Screening of barley cultivars or breeding lines could be best achieved by a combination of germination testing and measurement of photosynthetic rate and/or Na/K balance in young seedlings.
Mauro: a mid to late maturing cultivar of biserrula (Biserrula pelecinus)
Authors: Loi A. , Nutt B. J. , Revell C. K. , Sandral G. A. , Dear B. S.
Published: April 2006

Mauro is a new mid to late variety of biserrula. It was derived from a single plant selection from a population collected from a harsh and heavily grazed site in southern Sardinia, Italy. The later maturity, lower hard seed level and higher regeneration in the second year of Mauro compared with Casbah will enhance the performance of biserrula in areas with medium to high rainfall where permanent pasture or infrequent cropping are common.
DEMETER
and
REPRESSOR OF SILENCING 1
encode 5-methylcytosine DNA glycosylases
Authors: Morales-Ruiz Teresa , Ortega-Galisteo Ana Pilar , Ponferrada-Marín María Isabel , Martínez-Macías María Isabel , Ariza Rafael R. , Roldán-Arjona Teresa
Published: April 2006

Cytosine methylation is an epigenetic mark that promotes gene silencing and plays important roles in development and genome defense against transposons. Methylation patterns are established and maintained by DNA methyltransferases that catalyze transfer of a methyl group from
S
-adenosyl-
l
-methionine to cytosine bases in DNA. Erasure of cytosine methylation occurs during development, but the enzymatic basis of active demethylation remains controversial. In
Arabidopsis thaliana
,
DEMETER
(
DME
) activates the maternal expression of two imprinted genes silenced by methylation, and
REPRESSOR OF SILENCING 1
(
ROS1
) is required for release of transcriptional silencing of a hypermethylated transgene.
DME
and
ROS1
encode two closely related DNA glycosylase domain proteins, but it is unknown whether they participate directly in a DNA demethylation process or counteract silencing through an indirect effect on chromatin structure. Here we show that DME and ROS1 catalyze the release of 5-methylcytosine (5-meC) from DNA by a glycosylase/lyase mechanism. Both enzymes also remove thymine, but not uracil, mismatched to guanine. DME and ROS1 show a preference for 5-meC over thymine in the symmetric dinucleotide CpG context, where most plant DNA methylation occurs. Nevertheless, they also have significant activity on both substrates at CpApG and asymmetric sequences, which are additional methylation targets in plant genomes. These findings suggest that a function of ROS1 and DME is to initiate erasure of 5-meC through a base excision repair process and provide strong biochemical evidence for the existence of an active DNA demethylation pathway in plants.
Desulfuromonas svalbardensis sp. nov. and Desulfuromusa ferrireducens sp. nov., psychrophilic, Fe(III)-reducing bacteria isolated from Arctic sediments, Svalbard
Authors: Vandieken Verona , Mußmann Marc , Niemann Helge , Jørgensen Bo Barker
Published: April 2006

Two psychrophilic, Gram-negative, rod-shaped, motile bacteria (strains 112T and 102T) that conserved energy from dissimilatory Fe(III) reduction concomitant with acetate oxidation were isolated from permanently cold Arctic marine sediments. Both strains grew at temperatures down to −2 °C, with respective temperature optima of 14 °C and 14–17 °C for strains 112T and 102T. The isolated strains reduced Fe(III) using common fermentation products such as acetate, lactate, propionate, formate or hydrogen as electron donors, and they also grew with fumarate as the sole substrate. As alternatives to Fe(III), they reduced fumarate, S0 and Mn(IV). Based on 16S rRNA gene sequence similarity, strain 112T was most closely related to Desulfuromonas acetoxidans (97.0 %) and Desulfuromonas thiophila NZ27T (95.5 %), and strain 102T to Malonomonas rubra Gra Mal 1T (96.3 %) and Desulfuromusa succinoxidans GylacT (95.9 %) within the Deltaproteobacteria. Strains 112T and 102T therefore represent novel species, for which the names Desulfuromonas svalbardensis sp. nov. (type strain 112T=DSM 16958T=JCM 12927T) and Desulfuromusa ferrireducens sp. nov. (type strain 102T=DSM 16956T=JCM 12926T) are proposed.
Estimation of prokaryote genomic DNA G+C content by sequencing universally conserved genes
Authors: Fournier Pierre-Edouard , Suhre Karsten , Fournous Ghislain , Raoult Didier
Published: April 2006

Determination of the DNA G+C content of prokaryotic genomes using traditional methods is time-consuming and results may vary from laboratory to laboratory, depending on the technique used. We explored the possibility of extrapolating the genomic DNA G+C content of prokaryotes from gene sequences. For this, 127 universally conserved genes were studied from 50 prokaryotic genomes in the Clusters of Orthologous Groups database. Of these, 57 genes were present as a single copy in the genomes of 157 different prokaryote species available in GenBank. There was a strong correlation [coefficient of determination (r2) >95 %] between the DNA G+C contents of 20 genes and their corresponding genomes. For each of the 157 prokaryotic genomes studied, the DNA G+C content of the 20 genes was used to determine a ‘calculated’ genome DNA G+C content (CGC) and this value was compared with the ‘real’ genome DNA G+C content (RGC). In order to select the most suitable gene for the determination of CGC values, we compared ther2and median mol% difference between CGC and RGC as well as the sensitivity of each gene to provide CGC values for prokaryotic genomes that differ by less than 5 mol% from their RGC. The highly conservedftsYgene (median size 1144 nucleotides), a vertically inherited member of the GTPase superfamily, showed the highestr2value of 0.98, the smallest median mol% difference between CGC and RGC of 1.06 and a sensitivity of 100 %. UsingftsYDNA G+C content values, the CGC values of 100 genomes not included in the calculation ofr2differed by less than 5 mol% from their RGC values. These data suggest that the genomic DNA G+C content of prokaryotes may be estimated easily and reliably from theftsYgene sequence.
Cupriavidus pinatubonensis sp. nov. and Cupriavidus laharis sp. nov., novel hydrogen-oxidizing, facultatively chemolithotrophic bacteria isolated from volcanic mudflow deposits from Mt. Pinatubo in the Philippines
Authors: Sato Yoshinori , Nishihara Hirofumi , Yoshida Masao , Watanabe Makiko , Rondal Jose D. , Concepcion Rogelio N. , Ohta Hiroyuki
Published: April 2006

Taxonomic studies were performed on ten hydrogen-oxidizing, facultatively chemolithotrophic bacteria that were isolated from volcanic mudflow deposits derived from the eruption of Mt. Pinatubo in the Philippines in 1991. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these isolates belonged to the genusCupriavidusof theBetaproteobacteria; sequence similarity values with their nearest phylogenetic neighbour,Cupriavidus basilensis, were 97.1–98.3 %. In addition to phylogenetic analysis, results of whole-cell protein profiles and biochemical tests revealed that these strains were members of two distinct species. DNA–DNA hybridizations and whole-cell protein profiles enabled these isolates to be differentiated from relatedCupriavidusspecies with validly published names. The isolates were aerobic, Gram-negative, non-sporulating, peritrichously flagellated rods. Their G+C contents ranged from 65.2 to 65.9 mol% and their major isoprenoid quinone was ubiquinone Q-8. On the basis of these results, two novel species are proposed,Cupriavidus pinatubonensissp. nov. [nine strains, with 1245T(=CIP 108725T=PNCM 10346T) as the type strain] andCupriavidus laharissp. nov. [one strain, the type strain 1263aT(=CIP 108726T=PNCM 10347T)]. It is also suggested thatRalstoniasp. LMG 1197 (=JMP 134) should be included in the speciesC. pinatubonensis.
Two novel species, Lysobacter daejeonensis sp. nov. and Lysobacter yangpyeongensis sp. nov., isolated from Korean greenhouse soils
Authors: Weon Hang-Yeon , Kim Byung-Yong , Baek Youn-Kyung , Yoo Seung-Hee , Kwon Soon-Wo , Stackebrandt Erko , Go Seung-Joo
Published: April 2006

Two bacterial strains were isolated from greenhouse soils of Daejeon and Yangpyeong regions in Korea. The strains, designated GH1-9T and GH19-3T, were Gram-negative and aerobic, with rod-shaped cells. Their DNA G+C contents were 61.7 and 67.3 mol%, respectively. The major fatty acids of strain GH1-9T were iso-C16 : 0, iso-C15 : 0, iso-C14 : 0, iso-C17 : 1
ω9c and iso-C11 : 0 3-OH and the major components of strain GH19-3T were iso-C16 : 0, iso-C15 : 0, C16 : 1
ω7c alcohol, iso-C17 : 1
ω9c and iso-C11 : 0 3-OH. None of the species of the genus Lysobacter with validly published names showed 16S rRNA gene sequence similarity values of more than 97 % with respect to the novel isolates. The closest sequence similarity of strain GH1-9T was with Lysobacter concretionis DSM 16239T (96.4 %), whereas strain GH19-3T showed the highest sequence similarity with Lysobacter enzymogenes DSM 2043T (96.6 %). Polyphasic taxonomic studies indicated that the two strains should be classified as representing novel members of the genus Lysobacter. The names Lysobacter daejeonensis sp. nov. and Lysobacter yangpyeongensis sp. nov. are proposed, with strains GH1-9T (=KACC 11406T=DSM 17634T) and GH19-3T (=KACC 11407T=DSM 17635T), respectively, as the type strains.
Occurrence of the Cys611Tyr mutation and a novel Arg886Trp substitution in the RET proto‐oncogene in multiple endocrine neoplasia type 2 families and sporadic medullary thyroid carcinoma cases originating from the central region of Portugal
Authors: Prazeres Hugo João , Rodrigues Fernando , Figueiredo Paulo , Naidenov Plamen , Soares Paula , Bugalho Maria João , Lacerda Manuela , Campos Beatriz , Martins Teresa C.
Published: April 2006

Objective  Medullary thyroid carcinoma (MTC) occurs both sporadically and in the context of autosomal dominantly inherited multiple endocrine neoplasia type 2 (MEN2) syndromes: MEN2A, MEN2B, and familial medullary thyroid carcinoma (FMTC), which are caused by activating germline mutations in the RET proto‐oncogene. The aim of this study was to characterize the RET mutational spectrum in MEN2 families and apparently sporadic MTC (AS‐MTC) cases originating from the central region of Portugal.

Subjects and methods  We studied a total of 82 individuals (64 affected and 18 family members), comprising five MEN2 families (four MEN2A and one MEN2B), as well as 53 AS‐MTC cases. RET germline mutations were screened using PCR‐DNA sequencing, SSCP and RFLP. The haplotypes associated with recurrent mutations were determined by fragment analysis of microsatellite markers, and by RFLP, in the case of intragenic polymorphisms.

Results  Frequency of the Cys611Tyr (TGC‐TAC) mutation was significantly increased in this region of Portugal, due to the fact that three apparently unrelated MEN2A/FMTC families, out of the five in which mutations were identified, harboured this specific mutation. Haplotype analysis revealed that a common haplotype was shared between two of these three families. We have also characterized a novel RET mutation, Arg886Trp, located in the tyrosine kinase domain, which was found in an AS‐MTC case.

Conclusions  There are regional specificities in the relative frequency of RET mutations, which are consistent with a cluster‐like distribution of specific disease‐causing mutations, as a result of the inheritance of a shared haplotype. These data, along with the finding of a novel RET mutation (Arg886Trp), have important implications towards facilitating and improving the molecular diagnosis of hereditary MTC on a regional basis.
Starve and survive: stress tolerance and life‐history traits of a bdelloid rotifer
Authors: RICCI C. , PERLETTI F.
Published: April 2006

Bdelloid rotifers occur in unstable habitats, such as moss, lichens and temporary pools, where conditions change unpredictably and dramatically. Their ability to survive in such habitats could be related to their physiological ability to enter metabolic stasis in response to severe environmental stress. We tested the response of a bdelloid species (Macrotrachela quadricornifera Milne, 1886) to prolonged starvation by evaluating survival and fecundity once food was resupplied on a regular basis.

Animals were starved for different durations (20, 40, 60 days) and all survivors resumed reproduction. Life‐history parameters of the 20‐day starvation group subsequent to the resumption of normal feeding were studied.

From resumption of normal feeding, mean longevity and age‐specific traits of starved rotifers were the same as those of the fed rotifers. No reduction of lifetime fecundity was found in the bdelloids that experienced starvation, suggesting a time shift of the effective ‘age’ of the starved rotifers.

The response of the rotifer to starvation is similar to that induced by drought. The presence of a previously undocumented form of dormancy is hypothesized.
Growth–survival trade‐offs and allometries in rosette‐forming perennials
Authors: METCALF C. J. E. , REES M. , ALEXANDER J. M. , ROSE K.
Published: April 2006

Demographic rates such as growth and survival may interact directly as a result of allocation constraints, or indirectly through their relationship with structural characteristics.

We explored the relationship between growth and survival in a range of rosette‐forming species across different habitats, and investigated possible mechanistic explanations for the patterns we found.

Results indicated a negative association between growth and survival in small plants across species in different habitats. There was no relationship for large plants.

Relative growth rate (RGR) was positively correlated to specific leaf area (SLA), but unrelated to the percentage biomass allocated to roots. This argues against the hypothesized role of allocation to root mass in mediating the growth–survival trade‐off.

The pattern of biomass partitioning was compared with the predictions of Enquist & Niklas (2002a) Global allocation rules for patterns of biomass partitioning in seed plants. Science 295, 1517–1520. In agreement with their predictions, the overall relationship between above‐ and below‐ground biomass was isometric. However, after accounting for species‐specific effects it was found that allocation to roots varied widely between species and was size‐dependent, suggesting that the conventional statistical analysis (double‐log regression) may be insensitive to biologically important sources of variation.
Do bumble bees save time when choosing novel flowers by following conspecifics?
Authors: KAWAGUCHI L. G. , OHASHI K. , TOQUENAGA Y.
Published: April 2006

Spatio‐temporal variation in resource availability is often large and unpredictable. When animals need to find and sample novel foods, therefore they may prefer to choose food sources with feeding conspecifics or odour left by the conspecifics. This behaviour (local enhancement) would be favoured, especially if it decreases the time spent on food‐finding and subsequent decision‐making. In laboratory experiments we tested if naive bumble bees use local enhancement, and to what degree it could reduce the time spent on finding and sampling novel flowers.

When naive bees were presented with a pair of equally rewarded artificial or real flowers in a flight cage, they preferred to land and feed on the flower where a dead conspecific was attached. The presence of conspecifics reduced the time spent on detecting floral reward, which was significant only when bees chose between real flowers. In a similar pairwise choice, bees landed on artificial flowers with a dead conspecific wrapped in plastic more frequently than on flowers with the same‐sized plastic wrap including no bees, which suggests that visual cues have important influences on the bees’ flower choice.

Effects of conspecifics on flower choice and food detection time were most evident when they were attached to real flowers, and least evident when they were wrapped in plastic. These results suggest that the presence of conspecifics on flowers has stronger effects on bees’ decision‐making as the attractiveness of flowers increases, and that bees use both visual and non‐visual cues to recognize conspecifics on flowers.

If the benefit of saving time were universal, the use of local enhancement would also be advantageous when bees switch between focal flower species or sites in response to temporal changes in resource availability.
Phytohemagglutinin‐induced skin swelling in birds: histological support for a classic immunoecological technique
Authors: MARTIN L. B. , HAN P. , LEWITTES J. , KUHLMAN J. R. , KLASING K. C. , WIKELSKI M.
Published: April 2006

Measurements of phytohemagglutinin (PHA)‐induced tissue swelling are arguably the most popular surrogates for immunocompetence in wild birds. It is largely unresolved, however, whether the basic assumption underlying these measures is valid, particularly whether more swelling represents a ‘better’ or ‘stronger’ cell‐mediated immune response.

In this study we took a first step towards such validation by characterizing immune cell infiltration over time into the wing‐webs (patagia) of PHA‐challenged House Sparrows (Passer domesticus). Relative to saline‐injected wing‐webs, PHA‐injected wing‐webs displayed intensive infiltration of many immune cell types, including basophils, eosinophils, heterophils, lymphocytes, macrophages and thrombocytes. The abundance of most of these cell types changed over the course of the swelling response (6–48 h post‐injection). Peak infiltration time varied depending on cell type. At several time points, significant correlations between the numbers of some cell types (particularly heterophils) and the degree of swelling were detected.

Together, these data indicate that PHA‐induced swelling is related to heightened immune cell activity in House Sparrows, but also that the PHA swelling response in this species is dynamic and involves both innate and adaptive components of the immune system. We thus caution against interpreting larger swellings as ‘greater cell‐mediated immunocompetence’, given the complex nature of this immune response.
Decreased basal mucus secretion by Slp2‐a‐deficient gastric surface mucous cells
Authors: Saegusa Chika , Tanaka Toru , Tani Satoru , Itohara Shigeyoshi , Mikoshiba Katsuhiko , Fukuda Mitsunori
Published: April 2006

Synaptotagmin‐like protein (Slp) 2‐a is a putative Rab27A/B‐effector protein and is implicated in intracellular membrane transport. However, the precise tissue distribution of Slp2‐a protein and its functions remain largely unknown. In this study we used a specific anti‐Slp2‐a antibody to investigate the tissue distribution of Slp2‐a in mice and found that Slp2‐a is most abundantly expressed in mouse stomach. Co‐immunoprecipitation experiments indicated that Slp2‐a interacts with Rab27A/B in vivo. We also discovered that Slp2‐a and Rab27A/B are predominantly localized at the apical region of gastric‐surface mucous cells, where mucus granules are accumulated. Analysis of Slp2‐a mutant mice generated by homologous recombination showed a reduced number of mucus granules, a deficiency of granule docking with the apical plasma membrane in the gastric‐surface mucous cells and reduction of mucus secretion by Slp2‐a‐deficient gastric primary cells. Based on these results, we propose that Slp2‐a is part of the mucin secretory machinery in surface mucous cells of mouse stomach.
Inter‐ and intraspecific differences in climatically mediated phenological change in coexistingTriturusspecies
Authors: CHADWICK ELIZABETH A. , SLATER FREDERICK M. , ORMEROD S. J.
Published: April 2006

Climate and weather affect phenological events in a wide range of taxa, and future changes might disrupt ecological interactions. Amphibians are particularly sensitive to climate, but few studies have addressed climatically mediated change in the phenology of closely related species or sexes. Here, we test the hypothesis that changes in spring temperatures result in phenological change amongTriturus, and we examine inter‐ and intraspecific differences in response. Coexisting populations ofTriturus helveticusandTriturus vulgarisat Llysdinam pond in mid‐Wales (53°12′59″N 3°27′3″W) were monitored using pitfall traps along a drift fence during 1981–1987, and again in 1997–2005. Spring temperature over the same period explained up to 74% of between‐year variability in median arrival date, with a significant advance of 2–5 days with every degree centigrade increase. Changes were greater for males than females of both species, and greater forT. helveticusthanT. vulgariswithin sexes, resulting in an increasing temporal separation between arrivals of maleT. helveticusand all other groups. These data illustrate for the first time how climatic change might have differential effects on sympatric species and on the two sexes.
Different patterns of inflammation and prognosis in invasive carcinoma of the breast
Authors: Lee A H S , Gillett C E , Ryder K , Fentiman I S , Miles D W , Millis R R
Published: April 2006

Aim : Inflammation in carcinoma of the breast may represent an immune response to the tumour, but there is evidence that this response is impaired. Inflammation may also stimulate tumour growth by releasing proteolytic enzymes and angiogenic factors. Prognostic studies have produced conflicting results, but most investigators have not evaluated the different patterns of inflammation. The aim of this study was to test the hypothesis that moderate or marked diffuse inflammation is associated with a better prognosis. We also tested the ‘danger model’, which suggests that necrosis is necessary for an effective immune response.

Methods and results : On multivariate analysis of women with stage 1 and 2 tumours (n = 679, median follow‐up of 9.8 years), survival was independently associated with diffuse inflammation (relative risk 0.43, 95% confidence interval 0.24, 0.77, P =0.005) in addition to histological grade, axillary lymph node status, tumour size and oestrogen receptor status. The presence or absence of tumour necrosis did not have a clear effect on the relationship between survival and diffuse inflammation.

Conclusions : Moderate or marked diffuse inflammation in breast cancer is associated with a better prognosis, suggesting that the immune effects of the inflammation predominate over the protumour effects.
Behaviourally mediated indirect effects: interference competition increases predation mortality in foraging redshanks
Authors: MINDERMAN JEROEN , LIND JOHAN , CRESSWELL WILL
Published: April 2006

The effect of competition for a limiting resource on the population dynamics of competitors is usually assumed to operate directly through starvation, yet may also affect survival indirectly through behaviourally mediated effects that affect risk of predation. Thus, competition can affect more than two trophic levels, and we aim here to provide an example of this.

We show that the foraging success of redshanks Tringa totanus (L.) foraging on active prey was highest in the front of flocks, whereas this was not the case for redshanks foraging on inactive prey. Also, when foraging on active prey, foraging success in a flock decreased as more birds passed through a patch, while overall foraging success was not lower on subsequent visits to the same patch. Thus, redshanks foraging on active prey suffered from interference competition, whereas this was not the case for redshanks foraging on inactive prey.

This interference competition led to differences in activity: redshanks attaining a lower foraging success had a higher walking rate. Greater activity was associated with wider flock spacing and shorter distances to cover, which has previously been shown to increase predation risk and mortality from sparrowhawks Accipiter nisus (L.).

We conclude that behavioural adaptations of prey species can lead to interference competition in foraging redshanks, and thus can affect their predation risk and mortality through increased activity. This study is one of the first to show how interference competition can be a mechanism for behaviourally mediated indirect effects, and provides further evidence for the suggestion that a single species occupying an intermediate trophic level may be simultaneously top‐down controlled by a predator and bottom‐up controlled by a behavioural response of its prey.
Critical aneurysmal dilatation of the thoracic aorta in young adolescents with variant hyperimmunoglobulin E syndrome
Authors: VAN DER MEER J. W. M. , WEEMAES C. M. R. , VAN KRIEKEN J. H. , BLOMJOUS C. E. M. , VAN DIE C. E. , NETEA M. G. , BREDIE S. J. H.
Published: April 2006

The autosomal‐dominant (AD) form of the hyperimmunoglobulin E syndrome (HIES) has been described as a multisystem disorder including immune, skeletal and dental abnormalities. Recently, the evaluation of patients from families in which HIES was inherited in a manner more consistent with autosomal‐recessive (AR) inheritance, showed that AR‐HIES is a clinically distinct disease entity. In addition to classical immunologic findings of AD‐HIES, the AR form presents with severe recurrent fungal and viral infections with herpes zoster, herpes simplex and characteristic mollusca contagiosa. Furthermore, cerebral vascular sequelae, including vasculitis, infarction and haemorrhage were noted. In this report, we describe the clinical picture of two patients who showed remarkable resemblance to the description of AR‐HIES, but also developed fatal aneurysmal dilatation of the thoracic aorta in adolescence. This finding may further consummate the clinical picture of AR‐HIES and emphasize the possibility to develop early aortitis, most likely preceding the critical aneurysm formation at older age. This process should be anticipated during childhood in cases with AR‐HIES.
Prosthetic rehabilitation of a midfacial defect resulting from lethal midline granuloma – a clinical report
Authors: GUTTAL S. S. , PATIL N. P. , SHETYE A. D.
Published: April 2006

summary  Prosthetic rehabilitation of the midfacial defects has always perplexed maxillofacial prosthodontists. These midfacial defects lead to functional and cosmetic deficiencies. One of the causes of such defects is midline lethal granuloma, which is a destructive granulomatous lesion of uncertain aetiology, involving the nose, paranasal sinuses and the palate. Presented here is a clinical report of a 22‐year‐old male patient diagnosed to have lethal midline granuloma, who was referred to the Department of Prosthodontics, SDM College of Dental Sciences Dharwad. The patient had a severe midfacial defect involving the nose, the paranasal sinuses, the palate and the soft tissues of the face. Although the lesion was not of the rapidly progressive type at the time of rehabilitation, the non‐specific inflammatory process was persisting. The patient was treated with chemotherapy and palliative therapy. The primary objective of the prosthetic rehabilitation was to provide closure of the severe defect to protect the soft tissues from environmental exposure. Secondarily the prosthesis also provided acceptable aesthetics and psychological benefit to the patient.
Scurvy: a disease almost forgotten
Authors: Olmedo Jesse M. , Yiannias James A. , Windgassen Elizabeth B. , Gornet Michael K.
Published: April 2006

Background  Although much decreased in prevalence, scurvy still exists in industrialized societies. Few recent large studies have examined its pathogenesis, signs, and symptoms.

Methods  After we diagnosed scurvy in a 77‐year‐old female patient in 2003, we conducted a retrospective records review to identify patients with scurvy treated between 1976 and 2002 at Mayo Clinic (Scottsdale, Arizona; Rochester, Minnesota; or Jacksonville, Florida). We also searched the English‐language medical literature for published reports on scurvy.

Results  In addition to our patient, seven of 11 patients whose records in the institutional database mentioned vitamin C deficiency were women. The age ranged from a neonate to 77 years (mean, 48 years). The most common associated causes were concomitant gastrointestinal disease, poor dentition, food faddism, and alcoholism. Vitamin or mineral deficiencies other than vitamin C deficiency were also found in our patients who had scurvy. The most common symptoms were bruising, arthralgias, or joint swelling. The most common signs were pedal edema, bruising, or mucosal changes. Four patients had vague symptoms of myalgias and fatigue without classic findings, and five had concomitant nutritional deficiencies. Follow‐up available for six of 12 patients treated by vitamin C supplementation showed complete resolution of symptoms in five.

Conclusions  Patients with scurvy may present with classic symptoms and signs or with nonspecific clinical symptoms and an absence of diagnostically suggestive physical findings. Concomitant deficiency states occur not uncommonly. Taking a thorough dietary history and measuring serum ascorbic acid levels should be considered for patients with classic signs and symptoms, nonspecific musculoskeletal complaints, or other vitamin or mineral deficiencies.
The ethics of xenotransplantation: a survey of student attitudes
Authors: Pearce C. E. , Thomas A. P. M. , Clements D. A. V.
Published: April 2006

Pearce CE, Thomas APM, Clements DAV. The ethics of xenotransplantation: a survey of student attitudes. Xenotransplantation 2006; 13: 253–257. © Blackwell Munksgaard, 2006

Abstract:  Xenotransplantation is a burgeoning technology that could provide a solution to the shortage of organs and tissue for transplantation. It does, however, raise many moral and ethical dilemmas. The aim of this study was to evaluate undergraduate university students' knowledge and opinions on the controversial practice. Choice of science or arts subjects and gender were also assessed to establish if they were influencing factors. A total of 100 students, 50 science students and 50 arts students, answered a questionnaire. Seventy‐seven percent of the students had heard of xenotransplantation, 66% believed it would be beneficial to society and only 45% believed it to be ethically and morally acceptable. The medical need for organs was highlighted as the most important argument in favour, and the risk of infection was revealed to be the most important argument against xenotransplantation. The students would significantly prefer a human to non‐human animal organ, and did not believe the genetic modification of animals for transplantation was ethically acceptable. This study, in general, did not find that knowledge and acceptance of xenotransplantation was associated with subject background (i.e., science or arts courses) or gender.
Estimation of the parameters of cardiac function and of blood volume by arterial thermodilution in an infant animal model
Authors: LÓPEZ‐HERCE JESÚS , RUPÉREZ MARTA , SÁNCHEZ CÉSAR , GARCÍA CRISTINA , GARCÍA ELENA
Published: April 2006

Background:  Experimental studies in adults and in animals have reported that estimation of the intracardiac volumes by arterial thermodilution is a more reliable method of blood volume estimation than pressure measurement. The objective of this study has been to analyze the values of cardiac function and blood volume in an infant animal model using the arterial thermodilution technique.

Methods:  A total of 202 measurements of cardiac output were performed by femoral arterial thermodilution in 38 Maryland piglets weighing between 8 and 16 kg, to determine the normal values of blood volume obtained by arterial thermodilution (PiCCO method) in an infant animal model. The following parameters were measured: blood volume [global end‐diastolic volume index (GEDVI), total intrathoracic blood index (ITBI), extravascular lung water index (ELWI), systolic volume index (SVI)] and parameters of cardiac and vascular function [systolic volume index (SVI), cardiac function index (CFI), left ventricular contractility (Dp/dtmax), and systemic vascular resistance index) (SVRI)].

Results:  The cardiac index, 4.3 ± 1.2 l·min−1·m2, was within the normal range. The GEDVI, 198 ± 48.6 ml·m2, and ITBI, 574.1 ± 113.4 ml·m2, were lower than the normal values reported in adults, whereas the ELWI, 16.3 ± 5.2 ml·kg−1, was higher.

Conclusions:  Intrathoracic and intracardiac volume values obtained by arterial thermodilution are lower than those considered normal in the adult, whereas the extravascular lung water is higher. These values must be taken into account when the PiCCO method is used in small children.
High‐Resolution Characterization of Linkage Disequilibrium Structure and Selection of Tagging Single Nucleotide Polymorphisms: Application to the Cholesteryl Ester Transfer Protein Gene
Authors: Horne Benjamin D. , Carlquist John F. , Cannon‐Albright Lisa A. , Muhlestein Joseph B. , McKinney Jason T. , Kolek Matthew J. , Clarke Jessica L. , Anderson Jeffrey L. , Camp Nicola J.
Published: April 2006

Full characterization of intragenic variation may improve candidate gene associations. This study selected tagging (t) single nucleotide polymorphisms (SNPs) to comprehensively represent genetic variability in the cholesteryl ester transfer protein (CETP) gene. Nineteen SNPs were identified in 50 unrelated individuals in the SNP discovery phase, and 13 intronic SNPs were added from the literature. These 32 SNPs were genotyped in 339 apparently healthy individuals and 190 coronary artery disease (CAD) patients. Using phased haplotypes, linkage disequilibrium (LD) structure was characterized and tSNPs selected using a principal component analysis (PCA) method. In healthy individuals, seven LD groups were identified that accounted for 93.4% of the observed genetic variation. These LD groups highlighted a complex LD structure for CETP, including both recombination and mutation, and eleven tSNPs were selected. Among CAD patients the results were essentially the same. Results from PCA using diploid genotype data were reasonably comparable. Finally, the selected tSNPs successfully represented the association evidence discovered for all of the other SNPs studied. This study provides an optimal set of tSNPs for association analyses of CETP. The observed complexity of LD structure highlights the importance of using methods, such as PCA, that allow for multiple dynamics in intragenic LD structure.
FMR1 CGG Repeat Patterns and Flanking Haplotypes in Three Asian Populations and Their Relationship With Repeat Instability
Authors: Zhou Youyou , Tang Kun , Law Hai‐Yang , Ng Ivy S. L. , Lee Caroline G. L. , Chong Samuel S.
Published: April 2006

Hyper‐expansion of a CGG repeat in the 5′ untranslated region of the FMR1 gene followed by methylation and silencing is the predominant cause of Fragile X syndrome, the most common inherited mental retardation disorder. Most detailed studies of the FMR1 gene have focused on Caucasian populations and patients. We performed a detailed haplotype and linkage disequilibrium analysis of the FMR1 gene in a total of 454 unselected normal X chromosomes from three Asian populations, Chinese, Malay and Indian. Compared to Caucasians and African Americans, the diversity of normal FMR1 CGG repeat lengths, patterns and flanking haplotypes were lower in Asians. Strong linkage disequilibrium was observed between the CGG repeat and flanking FMR1 markers in all three Asian populations, with strong association between specific CGG repeat alleles and flanking marker alleles observed only in the Chinese and Malays. A test for randomness of distribution between FRAXA CGG repeat patterns and flanking FMR1 marker haplotypes also revealed a highly significant non‐random distribution between CGG repeat patterns and flanking haplotypes in all three ethnic groups (P < 0.001). Extending previous findings in Caucasians and African Americans we present a novel statistical approach, using data from unselected population samples alone, to show an association between absence of at least one AGG interruption in any position (5′, 3′, or middle) and increased CGG repeat instability.
Influence of Genetic Variation in the C‐Reactive Protein Gene on the Inflammatory Response During and After Acute Coronary Ischemia
Authors: Suk Danik J. , Chasman D. I. , Cannon C. P. , Miller D. T. , Zee R. Y. L. , Kozlowski P. , Kwiatkowski D. J. , Ridker P. M.
Published: April 2006

The aim of this research was to assess whether common genetic variants within the C‐reactive protein gene (CRP) are related to the degree of acute rise in plasma C‐reactive protein (CRP) levels following an acute coronary syndrome (ACS). While polymorphisms within CRP are associated with basal CRP levels in healthy men and women, less is known about the relationship of such genetic variants and the degree of CRP rise during and after acute ischemia. Plasma CRP is associated with increased rates of recurrent coronary events. We evaluated seven common genetic variants within CRP and assessed their relationship to the degree of rise in CRP levels immediately following an acute coronary syndrome in 1827 European American patients. Variants in the putative promoter region, −757T > C and −286C > T > A, were associated with the highest CRP elevations after ACS. Patients with two copies of the A allele of SNP −286C > T > A had median CRP values of 76.6 mg/L, compared to 11.1 mg/L in patients with no copies of the rare variant (p‐value <0.0001), post ACS. The lowest CRP values were found for patients with minor alleles of the exonic 1059G > C and the 3′untranslated region 1846G > A SNPs. For example, patients homozygous for the minor allele of 1059G > C had 71% lower median CRP values than those homozygous for the major allele [3.5 vs 12.0 mg/L, p < 0.0001]. These trends persisted in the chronic stable phase after ischemia had resolved, and after adjustment for infarct size by peak creatinine kinase levels and clinical status by Killip class. Assessment of CRP genetic variants identified patients with higher and lower CRP elevation after acute coronary syndrome.
Isolation of microsatellite loci and cross‐species amplifications in three gobiid fish of the genus Pomatoschistus
Authors: BERREBI PATRICK , LASSERRE BERNARD , BARBISAN FEDERICA , ZANE LORENZO
Published: April 2006

Gobiids of the genus Pomatoschistus are increasingly being investigated as models for adaptation to coastal environments and for mating system studies. Among the dozen currently analysed species, microsatellite primers have been characterized only for Pomatoschistus minutus. This paper describes seven new polymorphic loci isolated from Pomatoschistus marmoratus and Pomatoschistus microps, two species that hybridize. Cross‐species amplification was tested for these new loci, together with seven already published P. minutus loci. Systematic amplification of samples of each of the three species provided a first indication of their polymorphism.
Isolated bilateral blindness as the sole manifestation of transient ischaemic attacks
Authors: Krasnianski Michael , Bau Viktoria , Neudecker Stephan , Lindner Alfred , Zierz Stephan
Published: April 2006

Purpose:  To explain the rare phenomenon of acute transient bilateral blindness without additional ophthalmological or neurological symptoms and signs.

Methods:  Six patients with isolated bilateral visual loss lasting 1–15 mins and occurring simultaneously in both eyes were evaluated. Clinical observation, neuroimaging (CT, MRI, MR‐angiography), extra‐ and transcranial Doppler and vascular risk factors assessment were performed.

Results:  Cortical blindness due to bilateral occipital lobe transient ischaemic attacks (TIAs) was established as the most likely cause of acute transient visual loss in all patients.

Conclusion:  We suggest that in cases of transient bilateral blindness with sudden onset, appearing simultaneously in both visual fields, a bilateral ischaemia of the visual cortex should be suspected even if other neurological symptoms are lacking. Patients should be managed in the same way as patients with vertebrobasilar TIAs.