bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporation of growth factors into medical devices via biomimetic coatings
Authors: Liu Y , Li J.P , Hunziker E.B , de Groot K
Published: December 2005

Orthopaedic and dental surgeons are fully aware of the need for implants to bond well with the surrounding living bone if long-lasting clinical success is to be achieved. For example, well-bonded hip implants have a 10 year failure rate, which is lowered fivefold if bonding is poor or absent. The techniques that are currently available to impart implant surfaces with the desired osteoconductive properties are essentially limited. To overcome the inherent difficulties, we have developed a ‘biomimetic’ coating process. By this means, implants with complex surface geometries, such as porous spinal implants, can be furnished with a bone-bonding surface. Furthermore, these coatings can be rendered osteoinductive as well as osteoconductive (by incorporating osteogenic agents). Using this facility, we have induced bone formation at an ectopic site in rats, and have accelerated osseointegration (bone bonding) at an orthotopic dental site in adult miniature pigs. Our preliminary results indicated that these osteoinductive dental implants bond with surrounding bone within one week instead of the usual three weeks. We believe that surfaces coated with biomimetic coatings into which osteogenic growth factors are incorporated hold great potential for use in clinical orthopaedics and dentistry.
Design and processing of porous materials for electronic applications
Authors: Willoughby A.F.W
Published: December 2005

The use of porosity, either unintentionally or intentionally, in the fabrication of materials for electronic and optoelectronic applications is introduced. Unintentional uses include the fabrication of ceramic magnets, where high electrical resistivities are required to reduce eddy currents at high frequency, and the powder technology, often used, inevitably results in porosity. The generation of light from porous silicon created a huge impact in the early 1990s, followed by extensive work on the mechanism responsible, and has now been followed by a more balanced evaluation of its potential. Porous ferroelectrics have shown significant advantages over dense materials for positive temperature coefficient of resistance applications, and for sensors such as hydrophones, and these will be discussed. Low dielectric constant materials are required for the next generation of silicon integrated circuits, where a reduction compared with silicon dioxide is required, and here porosity is a convenient strategy. Finally, the use of deliberately engineered porous nanostructures, with dimensions in the range of the wavelength of light, are discussed for applications in optical processing.
Characterization and spontaneous mutation of a novel gene, polE, involved in pellicle formation in Acetobacter tropicalis SKU1100
Authors: Deeraksa Arpaporn , Moonmangmee Somporn , Toyama Hirohide , Yamada Mamoru , Adachi Osao , Matsushita Kazunobu
Published: December 2005

Acetobacter tropicalis SKU1100 produces a pellicle polysaccharide, consisting of galactose, glucose and rhamnose, which attaches to the cell surface. This strain forms two types of colony on agar plates: a rough-surfaced colony (R strain) and a mucoid smooth-surfaced colony (S strain). The R strain forms a pellicle, allowing it to float on the medium surface in static culture, while the S strain does not. The pellicle is an assemblage of cells which are tightly associated with capsular polysaccharides (CPS) on the cell surface. In this study, a gene required for pellicle formation by the R strain was investigated by transposon mutagenesis using Tn10. The resulting mutant, designated Pel−, has a smooth-surfaced colony and a defect in pellicle formation, as for the S strain. The mutant produced polysaccharide which was instead secreted into the culture medium as extracellular polysaccharide (EPS). An ORF was identified at the Tn10 insertion site, designated polE, upstream of which polABCD genes were also found. The deduced amino acid sequences of polABCD showed a high level of homology to those of rfbBACD which are involved in dTDP-rhamnose synthesis, whereas polE had a relatively low level of homology to glycosyltransferase. In this study a polB (rfbA) disruptant was also prepared, which lacked both CPS and EPS production. A plasmid harbouring the polE or polB genes could restore pellicle formation in the Pel− mutant and S strains, and in the ΔpolB mutant, respectively. Thus both polE and polB are evidently involved in pellicle formation, most likely by anchoring polysaccharide to the cell surface and through the production of dTDP-rhamnose, respectively. The Pel− and ΔpolB mutants were unable to grow in static culture and became more sensitive to acetic acid due to the loss of pellicle formation. Additionally, this study identified the mutation sites of several S strains which were spontaneously isolated from the original culture and found them to be concentrated in a sequence of 7 C residues in the coding sequence of polE, with the deletion or addition of a single C nucleotide.
Construction and expression of an ethanol production operon in Gram-positive bacteria
Authors: Talarico Lee A. , Gil Malgorzata A. , Yomano Lorraine P. , Ingram Lonnie O. , Maupin-Furlow Julie A.
Published: December 2005

Pyruvate decarboxylase (PDC), an enzyme central to homoethanol fermentation, catalyses the non-oxidative decarboxylation of pyruvate to acetaldehyde with release of carbon dioxide. PDC enzymes from diverse organisms have different kinetic properties, thermal stability and codon usage that are likely to offer unique advantages for the development of desirable Gram-positive biocatalysts for use in the ethanol industry. To examine this further, pdc genes from bacteria to yeast were expressed in the Gram-positive host Bacillus megaterium. The PDC activity and protein levels were determined for each strain. In addition, the levels of pdc-specific mRNA transcripts and stability of recombinant proteins were assessed. From this analysis, the pdc gene of Gram-positive Sarcina ventriculi was found to be the most advantageous for engineering high-level synthesis of PDC in a Gram-positive host. This gene was thus selected for transcriptional coupling to the alcohol dehydrogenase gene (adh) of Geobacillus stearothermophilus. The resulting Gram-positive ethanol production operon was expressed at high levels in B. megaterium. Extracts from this recombinant were shown to catalyse the production of ethanol from pyruvate.
Interaction between the X chromosome and an autosome regulates size sexual dimorphism in Portuguese Water Dogs
Authors: Chase Kevin , Carrier David R. , Adler Frederick R. , Ostrander Elaine A. , Lark Karl G.
Published: December 2005

Size sexual dimorphism occurs in almost all mammals. In Portuguese Water Dogs, much of the difference in skeletal size between females and males is due to the interaction between a Quantitative Trait Locus (QTL) on the X-chromosome and a QTL linked to Insulin-like Growth Factor 1 (IGF-1) on the CFA 15 autosome. In females, the haplotype of CFA 15 resulting in small size is dominant. In males, the haplotype for large size is dominant. Females, homozygous at the CHM marker on the X chromosome and homozygous for the large size CFA 15 haplotype are, on average, as large as large males. However, all females that are heterozygous at the CHM marker are small, regardless of their CFA 15 genotype. This interaction suggests a genetic mechanism that in turn leads to a scenario for the evolution of size sexual dimorphism consistent with a proposal of Lande that sexual dimorphism can evolve because females secondarily become smaller than males as a consequence of natural selection for optimal size. Our results also can explain Rensch's Rule, which states that size is often positively correlated with the level of size sexual dimorphism.
Drosophila melanogaster: A case study of a model genomic sequence and its consequences: Figure 1.
Authors: Ashburner Michael , Bergman Casey M.
Published: December 2005

The sequencing and annotation of the Drosophila melanogaster genome, first published in 2000 through collaboration between Celera Genomics and the Drosophila Genome Projects, has provided a number of important contributions to genome research. By demonstrating the utility of methods such as whole-genome shotgun sequencing and genome annotation by a community “jamboree,” the Drosophila genome established the precedents for the current paradigm used by most genome projects. Subsequent releases of the initial genome sequence have been improved by the Berkeley Drosophila Genome Project and annotated by FlyBase, the Drosophila community database, providing one of the highest-quality genome sequences and annotations for any organism. We discuss the impact of the growing number of genome sequences now available in the genus on current Drosophila research, and some of the biological questions that these resources will enable to be solved in the future.
The mouse genome
Authors: Guénet Jean Louis
Published: December 2005

The house mouse has been used as a privileged model organism since the early days of genetics, and the numerous experiments made with this small mammal have regularly contributed to enrich our knowledge of mammalian biology and pathology, ranging from embryonic development to metabolic disease, histocompatibility, immunology, behavior, and cancer. Over the past two decades, a number of large-scale integrated and concerted projects have been undertaken that will probably open a new era in the genetics of the species. The sequencing of the genome, which will allow researchers to make comparisons with other mammals and identify regions conserved by evolution, is probably the most important project, but many other initiatives, such as the massive production of point or chromosomal mutations associated with comprehensive and standardized phenotyping of the mutant phenotypes, will help annotation of the ∼25,000 genes packed in the mouse genome. In the same way, and as another consequence of the sequencing, the discovery of many single nucleotide polymorphisms and the development of new tools and resources, like the Collaborative Cross, will contribute to the development of modern quantitative genetics. It is clear that mouse genetics has changed dramatically over the last 10-15 years and its future looks promising.
Comparing the human and chimpanzee genomes: Searching for needles in a haystack
Authors: Varki Ajit , Altheide Tasha K.
Published: December 2005

The chimpanzee genome sequence is a long-awaited milestone, providing opportunities to explore primate evolution and genetic contributions to human physiology and disease. Humans and chimpanzees shared a common ancestor ∼5-7 million years ago (Mya). The difference between the two genomes is actually not ∼1%, but ∼4%—comprising ∼35 million single nucleotide differences and ∼90 Mb of insertions and deletions. The challenge is to identify the many evolutionarily, physiologically, and biomedically important differences scattered throughout these genomes while integrating these data with emerging knowledge about the corresponding “phenomes” and the relevant environmental influences. It is logical to tackle the genetic aspects via both genome-wide analyses and candidate gene studies. Genome-wide surveys could eliminate the majority of genomic sequence differences from consideration, while simultaneously identifying potential targets of opportunity. Meanwhile, candidate gene approaches can be based on such genomic surveys, on genes that may contribute to known differences in phenotypes or disease incidence/severity, or on mutations in the human population that impact unique aspects of the human condition. These two approaches will intersect at many levels and should be considered complementary. We also cite some known genetic differences between humans and great apes, realizing that these likely represent only the tip of the iceberg.
Genomics of the fungal kingdom: Insights into eukaryotic biology
Authors: Galagan James E. , Henn Matthew R. , Ma Li-Jun , Cuomo Christina A. , Birren Bruce
Published: December 2005

The last decade has witnessed a revolution in the genomics of the fungal kingdom. Since the sequencing of the first fungus in 1996, the number of available fungal genome sequences has increased by an order of magnitude. Over 40 complete fungal genomes have been publicly released with an equal number currently being sequenced—representing the widest sampling of genomes from any eukaryotic kingdom. Moreover, many of these sequenced species form clusters of related organisms designed to enable comparative studies. These data provide an unparalleled opportunity to study the biology and evolution of this medically, industrially, and environmentally important kingdom. In addition, fungi also serve as model organisms for all eukaryotes. The available fungal genomic resource, coupled with the experimental tractability of the fungi, is accelerating research into the fundamental aspects of eukaryotic biology. We provide here an overview of available fungal genomes and highlight some of the biological insights that have been derived through their analysis. We also discuss insights into the fundamental cellular biology shared between fungi and other eukaryotic organisms.
Emerging technologies in DNA sequencing
Authors: Metzker Michael L.
Published: December 2005

Demand for DNA sequence information has never been greater, yet current Sanger technology is too costly, time consuming, and labor intensive to meet this ongoing demand. Applications span numerous research interests, including sequence variation studies, comparative genomics and evolution, forensics, and diagnostic and applied therapeutics. Several emerging technologies show promise of delivering next-generation solutions for fast and affordable genome sequencing. In this review article, the DNA polymerase-dependent strategies of Sanger sequencing, single nucleotide addition, and cyclic reversible termination are discussed to highlight recent advances and potential challenges these technologies face in their development for ultrafast DNA sequencing.
Genetics of canid skeletal variation: Size and shape of the pelvis
Authors: Carrier David R. , Chase Kevin , Lark Karl G.
Published: December 2005

The mammalian skeleton presents an ideal system in which to study the genetic architecture of a set of related polygenic traits and the skeleton of the domestic dog (Canis familiaris) is arguably the best system in which to address the relationship between genes and anatomy. We have analyzed the genetic basis for skeletal variation in a population of >450 Portuguese Water Dogs. At this stage of this ongoing project, we have identified >40 putative quantitative trait loci (QTLs) for heritable skeletal phenotypes located on 22 different chromosomes, including the “X.” A striking aspect of these is the regulation of suites of traits representing bones located in different parts of the skeleton but related by function. Here we illustrate this by describing genetic variation in postcranial morphology. Two suites of traits are involved. One regulates the size of the pelvis relative to dimensions of the limb bones. The other regulates the shape of the pelvis. Both are examples of trade-offs that may be prototypical of different breeds. For the size of the pelvis relative to limb bones, we describe four QTLs located on autosome CFA 12, 30, 31, and X. For pelvic shape we describe QTLs on autosome CFA 2, 3, 22, and 36. The relation of these polygenic systems to musculoskeletal function is discussed.
Hotspots of mutation and breakage in dog and human chromosomes
Authors: Webber Caleb , Ponting Chris P.
Published: December 2005

Sequencing of the dog genome allows an investigation of the location-dependent evolutionary processes that occurred since the common ancestor of primates and carnivores, ∼95 million years ago. We investigated variations in G+C nucleotide fraction and synonymous nucleotide substitution rates (Ks) across dog and human genomes. Our results show that dog genes located either in subtelomeric and pericentromeric regions, or in short synteny blocks, possess significantly elevated G+C fraction andKsvalues. Human subtelomeric, but not pericentromeric, genes also exhibit these elevations. We then examined 1.048 Gb of human sequence that is likely not to have been located near a primate telomere at any time since the common ancestor of dog and human. We observed that regions of highest G+C orKs(“hotspots”; median sizes of 0.5 or 1.3 Mb, respectively) within this sequence were preferentially segregated to dog subtelomeres and pericentromeres during the rearrangements that eventually gave rise to the extant canine karyotype. Our data cannot be accounted for solely on the basis of gradually elevating G+C fractions in subtelomeric regions as a consequence of biased gene conversion. Rather, we propose that high G+C sequences are found preferentially within dog subtelomeres as a direct consequence of chromosomal fission occurring more frequently within regions elevated in G+C.
Chicken genome: Current status and future opportunities
Authors: Burt David W.
Published: December 2005

The chicken genome sequence is important for several reasons. First, the chicken shared a common ancestor with mammals ∼310 million years ago (Mya) at a phylogenetic distance not previously covered by other genome sequences. It therefore fills a gap in our knowledge and understanding of the evolution and conservation of genes, regulatory sequences, genomes, and karyotypes. The chicken is also a major source of protein in the world, with billions of birds used in meat and egg production each year. It is the first livestock species to be sequenced and so leads the way for others. The sequence and the 2.8 million genetic polymorphisms defined in a parallel project are expected to benefit agriculture and cast new light on animal domestication. Also, as the first bird to be sequenced, it is a model for the 9600 avian species thought to exist today. Many of the features of the chicken genome and its biology make it an ideal organism for studies in development and evolution, along with applications in agriculture and medicine.
Selective sweep mapping of genes with large phenotypic effects
Authors: Pollinger John P. , Bustamante Carlos D. , Fledel-Alon Adi , Schmutz Sheila , Gray Melissa M. , Wayne Robert K.
Published: December 2005

Many domestic dog breeds have originated through fixation of discrete mutations by intense artificial selection. As a result of this process, markers in the proximity of genes influencing breed-defining traits will have reduced variation (a selective sweep) and will show divergence in allele frequency. Consequently, low-resolution genomic scans can potentially be used to identify regions containing genes that have a major influence on breed-defining traits. We model the process of breed formation and show that the probability of two or three adjacent marker loci showing a spurious signal of selection within at least one breed (i.e., Type I error or false-positive rate) is low if highly variable and moderately spaced markers are utilized. We also use simulations with selection to demonstrate that even a moderately spaced set of highly polymorphic markers (e.g., one every 0.8 cM) has high power to detect regions targeted by strong artificial selection in dogs. Further, we show that a gene responsible for black coat color in the Large Munsterlander has a 40-Mb region surrounding the gene that is very low in heterozygosity for microsatellite markers. Similarly, we survey 302 microsatellite markers in the Dachshund and find three linked monomorphic microsatellite markers all within a 10-Mb region on chromosome 3. This region contains the FGFR3 gene, which is responsible for achondroplasia in humans, but not in dogs. Consequently, our results suggest that the causative mutation is a gene or regulatory region closely linked to FGFR3.
Structure and function of the human genome
Authors: Little Peter F.R.
Published: December 2005

The human genome project has had an impact on both biological research and its political organization; this review focuses primarily on the scientific novelty that has emerged from the project but also touches on its political dimensions. The project has generated both anticipated and novel information; in the later category are the description of the unusual distribution of genes, the prevalence of non-protein-coding genes, and the extraordinary evolutionary conservation of some regions of the genome. The applications of the sequence data are just starting to be felt in basic, rather than therapeutic, biomedical research and in the vibrant human origins and variation debates. The political impact of the project is in the unprecedented extent to which directed funding programs have emerged as drivers of basic research and the organization of the multidisciplinary groups that are needed to utilize the human DNA sequence.
Managing learner's expectations
Authors: Bell Christine
Published: December 2005

Purpose

To explore ways in which organizations can start moving from training‐centered approaches to learner‐centered approaches.

Design/methodology/approach

The article is based on work that the author has done with a variety of organizations that has helped to provide a transition from teaching to learning.

Findings

To move from training to learning needs learners to be involved and informed otherwise they will devalue the learning experience.

Practical implications

The article is about small‐scale changes that can be made to support learners in the transition period.

Originality/value

The article will be of value to managers and learning specialists who want to be more innovative in their design of learning programs.
Mentoring and the legal profession
Authors: Clutterbuck David
Published: December 2005

Purpose

To highlight and explore the reasons behind bad practice in mentoring among law firms, and to suggest how this can be rectified.

Design

The article is based on extensive research into mentoring programs in legal firms, which is benchmarked against my leading research into mentoring best practice.

Findings

Ineffective mentoring in the legal profession is evident due to lack of clarity of purpose, a lack of understanding of mentoring as a development process, ineffective mentoring dialogue and low emotional intelligence amongst many workers in the industry. All of these barriers need to be overcome for firms to see the real benefits of mentoring.

Practical implications

The article suggests key areas in which legal firms must effect change in order for mentoring to have a real effect on development and bring a host of related benefits.

Originality/value

The article will be of value to those in the legal profession who wish to develop their employees/themselves through effective mentoring. It is also a little‐explored area of mentoring study.
Identification of tumor associated antigens recognized by IgG from tumor‐infiltrating B cells of lung cancer: Correlation between Ab titer of the patient's sera and the clinical course
Authors: Mizukami Makiko , Hanagiri Takeshi , Baba Tetsuro , Fukuyama Takashi , Nagata Yoshika , So Tetsuya , Ichiki Yoshinobu , Sugaya Masakazu , Yasuda Manabu , Takenoyama Mitsuhiro , Sugio Kenji , Yasumoto Kosei
Published: December 2005

We previously demonstrated that TIB recognize tumor antigens and produce antibodies against them. In the present study, we identified three tumor antigens recognized by TIB in lung cancer and evaluated whether changes in the antibody titer against these antigens correlated with the patient's clinical course. A lung cancer cell line, G603L, was established from a primary lung tumor of a patient, G603. Seven months later, adrenal metastasis was detected and surgically resected. The latter tumor was mildly infiltrated with B cells and xenotransplanted into SCID mice to obtain human IgG. A cDNA library was constructed from G603L and SEREX was carried out using TIB‐derived IgG. The seroreactive clones were sequenced and one of these antigens was revealed to be MAGE‐B2 whereas the others were novel antigens. In the immunomonitoring of the patient's sera, high antibody titer against MAGE‐B2 was observed before operation and the titer decreased after resection of the primary tumor. It was elevated again at the time of adrenal metastasis, but then decreased after resection. The change in antibody titer against the second antigen was similar to MAGE‐B2, and the antibody titer against the third antigen was low before the primary operation but increased at the time of recurrence. Our results suggest that TIB recognized tumor antigens and the antibody titers against these antigens were changed along with the patient's clinical course. Therefore, these antibodies could be used as tumor markers for the patient. (Cancer Sci 2005; 96: 882–888)
Regulatory balance between the immune response of tumor antigen‐specific T‐cell receptor gene‐transduced CD8+ T cells and the suppressive effects of tolerogenic dendritic cells
Authors: Fujii Shin‐ichiro , Nishimura Michael I. , Lotze Michael T.
Published: December 2005

Tumor immune responses, including some immunotherapy strategies, can fail because of a number of reasons, such as poor tumor cell immunogenicity or local suppressive cytokine release by dendritic cells (DC) at tumor sites. The retroviral transfer of T‐cell receptor (TCR) genes encoding tumor‐specific receptors into T cells is a fascinating approach to bypass antigen‐presenting cells and allow T cells to directly recognize antigen. It also allows the generation and expansion of potent antitumor cytotoxic T lymphocytes with defined cancer antigen specificities more readily than naive T cells. However, interleukin‐10 (IL‐10)‐exposed dendritic cells (IL‐10‐DC) have been labeled tolerogenic because of the suppressive effects they have on T cell responses. Whether TCR gene‐transduced effector CD8+ T cells can break through suppressive functions mediated by IL‐10‐DC is not known. In the current study, we demonstrate the role of IL‐10 in modifying the function of DC that otherwise would activate potent TCR gene‐transduced T cells against tumor antigens. TCR gene‐transduced T cells maintained their cytolytic activity in the presence of DC exposed to low doses of IL‐10 during maturation; however, they lost this activity in an antigen‐specific manner when exposed to DC matured with high doses of IL‐10. (Cancer Sci 2005; 96: 897–902)
Role of Cys‐603 in dimer/oligomer formation of the breast cancer resistance protein BCRP/ABCG2
Authors: Kage Kumie , Fujita Toshiro , Sugimoto Yoshikazu
Published: December 2005

Breast cancer resistance protein (BCRP/ABCG2) is a half‐molecule ATP‐binding cassette transporter that we have previously suggested might function as a homodimer, bridged by disulfide bonds. In the present study, we carried out cysteine‐scanning mutagenesis, substituting Ser for Cys, and established 12 PA317 transfectants expressing BCRP mutants with possible disruptions to their S–S bonds. Western blot analysis of BCRP from the wild‐type transfectants (PA/WT) confirmed that the wild‐type protein migrates as a 140‐kDa dimer under non‐reducing conditions, but as a 70‐kDa monomer under reducing conditions. However, under non‐reducing conditions the BCRP‐C603S mutant migrated both as a 70‐kDa monomer and a 140‐kDa dimer, whereas all other mutant BCRP migrated only as dimers. PA317 cells transfected with C603S‐BCRP (PA/C603S) showed either similar or only marginally lower SN‐38 resistance than PA/WT cells, despite the reduced levels of BCRP dimer in these cells. Moreover, the degree of SN‐38 resistance in the mutant BCRP transfectants was found to be associated with the monomer expression levels under reducing conditions. Reverse transcription–polymerase chain reaction analysis showed that the BCRP mRNA levels were similar in the transfectants. We subsequently generated six C603X mutants of BCRP (X = D, H, R, Y, A and W) and carried out western blot analysis and drug sensitivity assays. The results were equivalent to those from the PA/C603S cells, with some variations that again corresponded to the monomer levels. Our findings suggest that Cys‐603 is an important residue in the covalent bridge between BCRP monomers but that a functioning unit of BCRP may not necessarily require covalent linkages. (Cancer Sci 2005; 96: 866–872)
µ‐Opiate receptor agonists – a new pharmacological approach to prevent motion sickness?
Authors: Otto Bärbel , Riepl Rudolf L. , Otto Carsten , Klose Joachim , Enck Paul , Klosterhalfen Sibylle
Published: December 2005

Aims

Stress hormones might be involved in motion sickness. The influence of loperamide on kinetosis‐induced nausea and stress hormone release was investigated in a placebo‐controlled, cross‐over study.

Methods

Standardized rotation around the vertical axis combined with head movements was used to induce nausea 3 h after 16 mg loperamide or placebo (n = 8). Plasma antidiuretic hormone (ADH), adrenocorticotropic hormone (ACTH) and nausea ratings were investigated.

Results

After loperamide nausea was significantly lower (P < 0.02). ACTH (P < 0.05) and ADH levels (P < 0.02) increased significantly in both settings, but were lower after loperamide.

Conclusions

The susceptibility to develop kinetosis‐induced nausea and stress hormone release is decreased by loperamide, although the site of action remains speculative.
The effects of near‐surface conditions on anisotropy parameter estimations from 4C seismic data
Authors: Traub Bärbel , Li Xiang‐Yang
Published: December 2005

We present a study of anisotropic parameter estimation in the near‐surface layers for P‐wave and converted‐wave (C‐wave) data. Near‐surface data is affected by apparent anisotropy due to a vertical velocity compaction gradient. We have carried out a modelling study, which showed that a velocity gradient introduces apparent anisotropy into an isotropic medium. Thus, parameter estimation will give anomalous values that affect the imaging of the target area.

The parameter estimation technique is also influenced by phase reversals with diminishing amplitude, leading to erroneous parameters. In a modelling study using a near‐surface model, we have observed phase reversals in near‐surface PP reflections. The values of the P‐wave anisotropy parameter η estimated from these events are about an order of magnitude larger than the model values. Next, we use C‐wave data to estimate the effect of anisotropy (χ) and compute η from these values. These calculated η‐values are closer to the model values, and NMO correction with both η‐values shows a better correction for the calculated value. Hence, we believe that calculating η from χ gives a better representation of the anisotropy than picked η from the P‐wave.

Finally, we extract the anisotropy parameters η and χ from real data from the Alba Field in the North Sea. Comparing the results with reference values from a model built according to well‐log, VSP and surface data, we find that the parameters show differences of up to an order of magnitude. The η‐values calculated from the C‐wave anisotropy parameter χ fit the reference values much better and show values of the same order of magnitude.
High‐resolution depth imaging with sparseness‐constrained inversion
Authors: Zhang Jianfeng , Wapenaar Kees
Published: December 2005

An imaging technique is developed which exceeds the resolution limitation prescribed by conventional seismic imaging methods. The high‐resolution imaging is obtained by introducing a sparseness‐constrained least‐squares inversion into the imaging process of prestack depth migration. This is implemented by a proposed interference technique. In contrast to conventional depth migration, a decomposed signal or combined event, instead of the source wavelet, is needed in the proposed scheme. The proposed method aims to image a small local region with a higher resolution using the prestack data set. It should be applied following conventional depth imaging if a higher resolution is needed in a target zone rather than replacing the conventional depth imaging for the entire medium. Synthetic examples demonstrate the significant improvements in the resolution using the proposed scheme.
Unexpected biodiversity loss under global warming in the neotropical Guayana Highlands: a preliminary appraisal
Authors: RULL VALENTÍ , VEGAS‐VILARRÚBIA TERESA
Published: December 2005

The fully vegetated summits of the table mountains that form the Guayana Highlands (GH), in northern South America, hold amazing biodiversity and endemism levels, and unique vegetation types. In spite of their present‐day healthy appearance, their biota is seriously threatened of habitat loss by upward displacement, because of the projected warming for the end of this century. Available data are still insufficient for a definite assessment, but preliminary estimations based on representative endemic vascular plant species show that roughly one‐tenth to one‐third of them would loss their habitat with the 2–4°C temperature increase predicted for the region by AD 2100. Given the underlying endemism, the eventual loss of biodiversity will be of global nature. Other mountain ranges around the world with similar characteristics of the GH, namely topographical isolation, high endemism and absence of nival stage because of the lower altitude, would be under similar unexpected risk, and should be urgently considered for conservation purposes.
Soil respiration in a Mediterranean oak forest at different developmental stages after coppicing
Authors: TEDESCHI VANESSA , REY ANA , MANCA GIOVANNI , VALENTINI RICCARDO , JARVIS PAUL G. , BORGHETTI MARCO
Published: December 2005

To assess the variation of soil respiration at different forest stages we measured it in a coppiced oak (Quercus cerris L.) chronosequence in central Italy during two campaigns, spanning 2 successive years, in four stands at different stages of the rotation: 1 year (S1), 5 years (S5), 10 years (S10) and 17 years (S17) after coppicing. The contribution of the different components of soil respiration flux (aboveground litter, belowground decomposition soil organic matter and root respiration) was estimated by a paired comparison of manipulative experiments between the recently coppiced stand (S1) and mature stand (S17).

Ninety percent of soil respiration values were between 1.7 and 7.8 μmol m−2 s−1, with an overall mean (±SD) of 4.0±2.7 μmol m−2 s−1. Spatial variation of soil respiration was high (CV=44.9%), with a mean range (i.e. patch size) of 4.8±2.7 m, as estimated from a semivariance analysis.

In the absence of limitation by soil moisture, soil respiration was related to soil temperature with the exponential Q10 model (average Q10=2.25). During summer, soil moisture constrained soil respiration and masked its dependence on soil temperature. Soil respiration declined over the years after coppicing. Assuming a linear decline with stand age, we estimated a reduction of 24% over a 20‐year‐rotation cycle. The response of soil respiration to temperature also changed with age of the stands: the Q10 was estimated to decrease from 2.90 in S1 to 2.42 in S17, suggesting that different components or processes may be involved at different developmental stages. The contribution of heterotrophic respiration to total soil respiration flux was relatively larger in the young S1 stand than in the mature S17 stand.
Protection of non‐obese diabetic mice from autoimmune diabetes by Escherichia coli heat‐labile enterotoxin B subunit
Authors: Ola Thomas O. , Williams Neil A.
Published: December 2005

Autoimmune diabetes in the non‐obese diabetic (NOD) mouse is associated with development of inflammation around the islets at around 4–5 weeks of age, which may be prolonged until frank diabetes begins to occur around 12 weeks of age. Although many interventions can halt disease progression if administration coincides with the beginning of the anti‐β cell response, very few are able to prevent diabetes development once insulitis is established. Here we describe a strategy which blocks cellular infiltration of islets and prevents diabetes. Intranasal treatment with the B‐subunit of Escherichia coli heat labile enterotoxin (EtxB), a protein that binds GM1 ganglioside (as well as GD1b, asialo‐GM1 and lactosylceramide with lower affinities), protected NOD mice from developing diabetes in a receptor‐binding dependent manner. Protection was associated with a significant reduction in the number of macrophages, CD4+ T cells, B cells, major histocompatibility complex class II+ cells infiltrating the islets. Despite this, treated mice showed increased number of interleukin‐10+ cells in the pancreas, and a decrease in both T helper 1 (Th1) and Th2 cytokine production in the pancreatic lymph node. Disease protection was also transferred with CD4+ splenocytes from treated mice. Taken together, these results demonstrated that EtxB is a potent immune modulator capable of blocking diabetes.
An unusual complication of mandibular distraction
Authors: PARASHAR S. Y. , ANDERSON P. J. , DAVID D. J.
Published: December 2005

Summary. Background. The authors present an unusual complication of mandibular distraction in a child with the curious condition of multiple pterygium syndrome is presented.

Case report. The patient was a Caucasian male with severe pterygia in his neck. As a result of his limited mouth opening and restricted upper airway leading to obstruction, he underwent lengthening of his mandible by distraction, which significantly improved his breathing. During his follow‐up, it was observed that an unusually elongated permanent molar was present in an abnormal position.

Conclusion. This case highlights the need to carefully plan the sites for osteotomy and the potential for damage to the developing permanent dentition in young children.
An oral health education programme based on the National Curriculum
Authors: CHAPMAN A. , COPESTAKE S. J. , DUNCAN K.
Published: December 2005

Summary.  Aim. The aim of this study was to develop and evaluate a teaching programme based on the national curriculum for use in a primary school setting.

Design. National Curriculum guidelines were combined with oral health education messages to draw up lesson plans for teachers to deliver. A questionnaire was used to demonstrate children's oral health knowledge prior to the teaching programme, and at 1 and 7 weeks following the programme.

The study took place in inner‐city, state‐run primary schools in Manchester and North London, UK.

The subjects were children between the ages of 7 and 8 years from Manchester (n = 58) and North London (n = 30).

The main outcome measure was change in knowledge attributable to a newly developed teaching programme.

Results. The children in Manchester had a higher level of knowledge prior to the teaching programme. Following the teaching programme, children in both schools showed a significant improvement in dental health knowledge (P < 0·001). Seven weeks later, the Manchester children showed no significant loss of knowledge (P < 0·001).

Conclusions. The aims of the National Curriculum were easily integrated with oral health messages. A more widely available teaching resource, such as the one described in this study, would be useful to encourage the teaching profession to take on oral health education without more costly input from dental professionals.
The frequency of repeat general anaesthesia for teeth extractions in children
Authors: ALBADRI S. S. , JARAD F. D. , LEE G. T. , MACKIE I. C.
Published: December 2005

Summary.  Aim. The purpose of this study was to determine the frequency of repeat extractions under general anaesthesia (GA) in children.

Methods. The dental hospital records of patients attending for outpatient GA extractions at Liverpool University Dental Hospital, Liverpool, UK, between January and March 2003 were examined retrospectively. A data collection form was used to record the relevant information.

Results. A total of 278 patients with a mean age of 6·5 years (SD = 2·2 years) were seen for GA extractions. Of those, 33 patients (11·9%) with a mean age of 4·9 years (SD = 2 years) at the time of their initial GA had had a previous or would undergo a subsequent episode of GA extraction. The mean interval between repeat GA was 2·3 years (SD = 1·6 years). Fifteen cases (45·5%) had the repeat GA within 2 years. Radiographs were available as part of the assessment process for 84 (34·3%) of the 245 patients who had had a single episode of GA. However, of the 33 patients who had had a repeat GA, only seven (21·2%) had radiographs available at the time of the initial GA. Regarding the number of teeth extracted, a significant difference (P < 0·01) was found between the number of teeth extracted in patients who had had a single GA (mean = 4·6, SD = 2·5), compared with those extracted at the initial GA for the repeat GA group (mean = 3·2, SD = 2).

Conclusion. The frequency of repeat GA is relatively low, but there is a need for appropriate treatment planning incorporating the use of radiographs to reduce this even further.
Clinical performance of resin‐bonded composite strip crowns in primary incisors: a retrospective study
Authors: RAM D. , FUKS A. B.
Published: December 2005

Summary.  Aim. The purpose of this study was to assess retrospectively the longevity of resin‐bonded composite strip crowns placed in primary maxillary incisors.

Design. Records for 200 out of 387 children, aged 22–48 months, treated in a private paediatric dental practice and who presented for follow‐up after at least 24 months were included in the study. The parameters recorded at baseline and/or at follow‐up were: habits, the number and location of the decayed surfaces, colour, texture, and chipping of the restoration. Radiographic evaluation of the restorations, the quality of the margins, and the presence of pulpal and/or periapical pathoses were recorded.

Results. More than 80% of the restorations were judged to be successful at the final follow‐up examination. Only the number of carious surfaces of the tooth at baseline influenced the treatment outcome. The failure rate was higher in central incisors with four affected surfaces (P = 0·005), and in lateral incisors with four carious surfaces (P = 0·0003), than in those presenting one or two carious surfaces in both central and lateral incisors (P = 0·002).

Conclusion. The high success rate of resin‐bonded composite strip crowns with a 2‐year follow‐up seen in this study suggests that this treatment modality is an aesthetic and satisfactory means of restoring carious primary incisors in young children. The retention rate is lower in teeth with decay in three or more surfaces, particularly in children with a high caries risk.
Immunocytochemical investigation of immune cells within human primary and permanent tooth pulp
Authors: RODD H. D. , BOISSONADE F. M.
Published: December 2005

Summary. Aim.  The aim of this study was to determine whether there are any differences in the number and distribution of immune cells within human primary and permanent tooth pulp, both in health and disease.

Design.  The research took the form of a quantitative immunocytochemical study.

One hundred and twenty‐four mandibular first permanent molars and second primary molars were obtained from children requiring dental extractions under general anaesthesia. Following exodontia, 10‐µm‐thick frozen pulp sections were processed for indirect immunofluorescence. Triple‐labelling regimes were employed using combinations of the following: (1) protein gene product 9·5, a general neuronal marker; (2) leucocyte common antigen (LCA); and (3) Ulex europaeus I lectin, a marker of vascular endothelium. Image analysis was then used to determine the percentage area of immunostaining for LCA.

Results.  Leucocytes were significantly more abundant in the pulp horn and mid‐coronal region of intact and carious primary teeth, as compared to permanent teeth (P < 0·05, anova). Both dentitions demonstrated the presence of well‐localized inflammatory cell infiltrates and marked aborization of pulpal nerves in areas of dense leucocyte accumulation.

Conclusions.  Primary and permanent tooth pulps appear to have a similar potential to mount inflammatory responses to gross caries The management of the compromised primary tooth pulp needs to be reappraised in the light of these findings.
An analysis of oral and maxillofacial pathology found in children over a 30‐year period
Authors: JONES A. V. , FRANKLIN C. D.
Published: December 2005

Summary. Aim. The vast majority of oral diseases are confined to oral tissues, but numerous underlying systemic conditions may present with signs and symptoms within the oral cavity. Since the epidemiology of diseases is variable between regions, the authors carried out Europe's first paediatric‐based survey of oral and maxillofacial pathology specimens submitted for diagnosis.

Design. All entries for specimens from children between the ages of 0 and 16 years during the 30‐year period from 1973 to 2002 were retrieved and compiled into 12 diagnostic categories.

Results. During the study period, 4406 (8·2%) specimens came from children between the ages of 0 and 16 years, with a male to female ratio of 1·01. The diagnostic category with the largest number of specimens was tooth pathology (22·1%), followed by salivary gland disease (19·1%) and mucosal pathology (12·1%). In all, there were 114 benign tumours of nonodontogenic origin, 43 odontogenic tumours and 31 malignant tumours. The most frequently diagnosed lesions were mucous extravasation cysts, which accounted for over 16% of cases. Periapical pathology in the form of a radicular cyst, residual cyst or chronic periapical granuloma formed almost 13% of all cases.

Conclusions. This survey shows that, while nearly 10% of specimens submitted to the authors’ laboratory are from children under 16 years of age, the majority of lesions are of a benign nature, requiring minimal intervention; less than 1% of cases comprise malignant lesions. Odontogenic tumours are relatively rare in this age group; however, certain lesions such as adenomatoid odontogenic tumour and ameloblastic fibroma occur predominantly in children and, therefore, remain an important diagnostic consideration.
Early symptoms of mania and the role of parental risk
Authors: Findling Robert L , Youngstrom Eric A , McNamara Nora K , Stansbrey Robert J , Demeter Christine A , Bedoya Denise , Kahana Shoshana Y , Calabrese Joseph R
Published: December 2005

Objectives:  The objectives of this study were to: (i) describe the phenomenology of youths diagnosed with subsyndromal bipolar disorders; (ii) describe the phenomenology of youngsters who are the children of bipolar parents, who are also experiencing subsyndromal symptoms of bipolar disorder (patients with ‘cyclotaxia’); and (iii) explore which symptoms may be most useful in identifying youths with cyclotaxia.

Methods:  Four hundred outpatients between the ages of 5 and 17 years received a diagnostic assessment and psychometric questionnaires pertaining to mood symptomatology and psychosocial functioning. Parental diagnostic information was also obtained. Children and adolescents were assigned to one of three diagnostic groups: a ‘syndromal bipolar disorder (BP)’ group (n = 118), a ‘sub‐syndromal bipolar (SUB‐BP)’ group (n = 75), or a ‘non‐bipolar (NON‐BP)’ group (n = 207). In addition, based on parental diagnoses, youths were assigned to either a high genetic risk group (n = 167) or a low genetic risk group (n = 233).

Results:  Youths with subsyndromal bipolar disorders were found to have intermediate degrees of manic symptoms than youths with bipolar disorder and youths without a bipolar diagnosis. Offspring of parents having a bipolar disorder were more likely to show symptoms of hypomania and mania than youths without a bipolar parent. Youths at genetic risk for developing a bipolar disorder were not found to be at higher risk for having a diagnosis of attention‐deficit hyperactivity disorder or a disruptive behavior disorder. Finally, results suggest that elevated mood with irritability and rapid mood fluctuations are the key distinguishing characteristics of ‘cyclotaxia’.

Conclusions:  There exists a group of youngsters who are the offspring of a parent/parents with a bipolar disorder who do not suffer from BP 1 or BP 2, yet have elevated mood symptoms and psychosocial dysfunction. As a result of these observations, treatment studies are needed for youths with ‘cyclotaxia’.