bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of human β‐secretase in the mouse brain increases the steady‐state level of β‐amyloid
Authors: Bodendorf Ursula , Danner Simone , Fischer Frauke , Stefani Muriel , Sturchler‐Pierrat Christine , Wiederhold Karl‐Heinz , Staufenbiel Matthias , Paganetti Paolo
Published: March 2003

β‐Site APP‐cleaving enzyme (BACE) initiates the processing of the amyloid precursor protein (APP) leading to the generation of β‐amyloid, the main component of Alzheimer's disease senile plaques. BACE (Asp2, memapsin 2) is a type I transmembrane aspartyl protease and is responsible for the β‐secretase cleavage of APP producing different endoproteolytic fragments referred to as the carboxy‐terminal C99, C89 and the soluble ectodomain sAPPβ. Here we describe two transgenic mouse lines expressing human BACE in the brain. Overexpression of BACE augments the amyloidogenic processing of APP as demonstrated by decreased levels of full‐length APP and increased levels of C99 and C89 in vivo. In mice expressing huBACE in addition to human APP wild‐type or carrying the Swedish mutation, the induction of APP processing characterized by elevated C99, C89 and sAPPβ, results in increased brain levels of β‐amyloid peptides Aβ40 and Aβ42 at steady‐state.
Promotion of neuronal cell adhesion by members of the IgLON family occurs in the absence of either support or modification of neurite outgrowth
Authors: McNamee Christine J. , Reed James E. , Howard Mark R. , Lodge Anthony P. , Moss Diana J.
Published: March 2003

The IgLONs are a family of glycosyl phosphatidyl inositol‐linked cell adhesion molecules which are thought to modify neurite outgrowth and may play a role in cell–cell recognition. The family consists of LAMP, OBCAM, neurotrimin/CEPU‐1 and neurotractin/kilon. In this paper we report the effect of recombinant LAMP, CEPU‐1 and OBCAM, and transfected cell lines expressing these molecules, on the adhesion and outgrowth of dorsal root ganglion (DRG) and sympathetic neurones. CHO cells transfected with cDNA for CEPU‐1 adhered to a recombinant CEPU‐1‐Fc substrate. However, DRG or sympathetic neurones only adhered to CEPU‐1‐Fc when presented on protein A. Although DRG and sympathetic neurones express IgLONs on their surface, both types of neurones exhibited differential adhesion to CEPU‐1‐Fc, LAMP‐Fc and OBCAM‐Fc. Neither DRG nor sympathetic neurones extended neurites on a protein A/IgLON‐Fc substrate and overexpression of CEPU‐1‐GFP in DRG neurones also failed to stimulate neurite outgrowth on an IgLON‐Fc substrate. DRG neurones adhered to and extended neurites equally on transfected and non‐transfected cell lines and the recombinant proteins did not modulate the outgrowth of neurones on laminin. In contrast to previous reports we suggest that IgLONs may not have a primary role in axon guidance but may be more important for cell–cell adhesion and recognition.
Arbuscular mycorrhizal colonization increases with host density in a heathland community
Authors: Genney David R. , Hartley Sue H. , Alexander Ian J.
Published: March 2003

The relationship is examined here between Nardus stricta root length colonized (RLC) by arbuscular mycorrhizal (AM) fungi (% RLC) and vegetation composition in a heathland community.

Two approaches were taken: a field survey of AM colonization of Nardus at two contrasting locations (Glen Clunie and Glen Shee, UK) in relation to vegetation composition; and an 11‐month bioassay of AM inoculum potential in Calluna vulgaris and Nardus swards using uncolonized Nardus transplants.

In the field survey, % RLC of Nardus was positively related to Nardus density. This relationship was strongest in Glen Clunie, probably because overall colonization levels were lower at the more fertile Glen Shee site. In the bioassay, Nardus transplants within Calluna swards developed little or no AM colonization, whereas those within Nardus swards had a mean RLC of 23%.

This is the first report that degree of AM colonization is related to host density in the field. Isolated Nardus plants in Calluna swards might be disadvantaged compared with Nardus plants in Nardus swards because of lower of AM colonization.
Substrate‐derived CO2 is important in the development of Sphagnum spp.
Authors: Smolders A. J. P. , Tomassen H. B. M. , Pijnappel H. W. , Lamers L. P. M. , Roelofs J. G. M.
Published: March 2003

The effects of different CO2 concentrations in the acrotelm pore water on the development of Sphagnum magellanicum monoliths grown in wet conditions in the laboratory are reported here.

Decomposition processes result in much higher CO2 concentrations in bog acrotelms than atmospheric concentrations. We therefore hypothesized that this substrate‐derived carbon provides an important carbon source for Sphagnum.

 S. magellanicum hummocks developed only when CO2 concentrations in the acrotelm water were high. Plants in the low CO2 treatment appeared to be carbon‐limited; they had increased nutrient concentrations and decreased ratios of carbon to other nutrients. Chlorophyll concentrations were much higher in these plants, probably allowing them to harvest more CO2, but the allocation of carbon to structural tissues was lower, resulting in weak stems that were unable to remain upright. As a result of carbon‐limitation, net biomass and height increases of the monoliths were much lower in the low CO2 treatment.

Results indicate that, at least in wet conditions, atmospheric CO2 alone is not sufficient to enable S. magellanicum to develop its normal vertical growth pattern. We conclude that the role of substrate‐derived CO2 as a carbon source for Sphagna is underestimated and requires reconsideration.
Ectomycorrhizas increase apoplastic water transport and root hydraulic conductivity in Ulmus americana seedlings
Authors: Muhsin T. M. , Zwiazek J. J.
Published: March 2003

The extent to which water channel transport is responsible for the observed increases in root water flow of ectomycorrhizal plants is reported here.

To examine the contribution of water channel transport to root hydraulic conductance, temperatures in the range 4–20°C and mercuric chloride (HgCl2) were used to study the kinetics of water transport in ectomycorrhizal and nonmycorrhizal roots of American elm (Ulmus americana) seedlings.

Hydraulic conductance declined with decreasing temperatures in both mycorrhizal and nonmycorrhizal seedlings. However, hydraulic conductance and conductivity were higher in the mycorrhizal than the nonmycorrhizal roots at all temperatures studied. Mercuric chloride had a relatively greater impact on root hydraulic conductance in nonmycorrhizal than mycorrhizal roots and activation energy for root hydraulic conductance was significantly higher in mycorrhizal than nonmycorrhizal plants.

The results suggest that ectomycorrhizal hyphae increase hydraulic conductance of roots by decreasing water flow resistance of the apoplast rather than by water channel‐mediated transport. The high rates of hydraulic conductance at low root temperatures might be important to plants growing in cold soils and under other challenging environmental conditions that inhibit metabolism and limit water transport.
Phosphorus and the regulation of nodulation in the actinorhizal symbiosis between Discaria trinervis (Rhamnaceae) and Frankia BCU110501
Authors: Valverde Claudio , Ferrari Alejandro , Gabriel Wall Luis
Published: March 2003

After nitrogen (N), phosphorus (P) is the nutrient that most limits plant productivity. The role of P on growth and root nodulation was studied in the actinorhizal symbiosis between Discaria trinervis and Frankia, an intercellular infected N2–fixing association.

Growth, nodulation and nutrient content (N and P) were analysed in symbiotic plants receiving different supplies of P in nutrient solutions. The relative requirement of P for nodulation was analysed in P‐deficient plants.

Nodule initiation was less impaired than general plant growth by low P. However, low P impaired nodule growth to a greater extent than plant growth. The proportion of nodule biomass, although not the number of nodules per plant, was stimulated by P supply. Autoregulation of nodulation was not affected by P. Use of N was limited by availability of P. Reserves of P in seeds were enough for the seedling to establish nodules. However nodule (and plant) growth was limited in the absence of exogenous P.

It is possible that P interacts with the feedback control of nodule growth that is associated with the plant demand for N. Leaf N : P ratio is negatively correlated with the proportion of nodule tissue.
Epicormic strand structure in Angophora, Eucalyptus and Lophostemon (Myrtaceae) – implications for fire resistance and recovery
Authors: Burrows G. E.
Published: March 2003

Epicormic bud producing structures in the eucalypts, a large group of woody plants of considerable ecological, horticultural and silvicultural importance, are described here.

The outer portion of epicormic strands excised from the bark of large diameter stems of 18 Eucalyptus species, two Angophora species and Lophostemon confertus was examined anatomically in semithin sections.

In the inner bark each eucalypt strand usually possessed 5–12 radially orientated strips of tissue of meristematic appearance. The meristem strips were c. 30–50 µm high, 70–110 µm wide and 2000–10 000 µm long, with a lacuna above the meristem surface. Few buds or bud primordia were associated with the strands and the strands appeared to have a reduced regenerative potential in the outer bark.

In most angiosperm trees dormant epicormic buds are present in the outer bark, a position where they could be killed by fire. By contrast, in eucalypts the greatest epicormic bud initiation potential is at the level of the vascular cambium, which is protected by the maximum bark thickness. This might explain the pronounced ability of eucalypts to produce bole and branch epicormic shoots after moderate to intense fire.
Genetic diversity in populations of the fungi Phaeomoniella chlamydospora and Phaeoacremonium aleophilum on grapevine in France
Authors: Borie B. , Jacquiot L. , Jamaux‐Despréaux I. , Larignon P. , Péros J.‐P.
Published: March 2003

Isolates of Phaeomoniella chlamydospora (Phc) and Phaeoacremonium aleophilum (Pha), two haploid, deuteromycetous fungi, were obtained from vines showing symptoms of esca disease in different localities in two French regions, and within a single vineyard in one of these regions. The population genetic structure was determined in both fungi using random amplified polymorphic DNA (RAPD) analysis. Populations of Phc showed similar levels of diversity at local and regional levels. The most frequent Phc haplotypes were found in every population, and the frequencies of positive alleles of markers were similar across populations. The hypothesis that recombination had occurred was rejected for the full set of samples, but not for the samples reduced to haplotypes, indicating that Phc may be a recombining species. Different features were identified in Pha populations. First, the southern population of Pha appeared more diverse than the south‐western populations. Second, genetic differentiation was identified between Pha populations from southern and south‐western regions for several RAPDs. Finally, in the southern population of Pha no evidence for recombination was obtained, even by reducing the sample to haplotypes. Within the single vineyard surveyed, several haplotypes of both fungi were recovered and randomly distributed. Thus different infection events appeared to have occurred on a low spatial scale. Data from this study showed that haplotypes of both fungi were distributed over long distances geographically, and that most of the vineyards surveyed were infested by more than one haplotype of Phc and Pha.
Antigenemia at 10 years after diethylcarbamazine treatment of asymptomatic microfilaraemic individuals: marginal conversion to infection‐free state
Authors: Beuria M. K. , Bal M. S. , Mandal N. N. , Das M. K.
Published: March 2003

A group of asymptomatic microfilaraemic individuals (n = 44, 29 males, 15 females) living in a Wuchereria bancrofti endemic region of Orissa, India, was treated with a standard regimen of diethylcarbamazine (12 days, 6 mg/kg) in 1990. The incidence of microfilaraemia and antigenemia (Og4C3) was determined after a gap of 10 years in 2000. Nineteen individuals reacquired microfilariae (43·2%, 11 males, eight females), five males developed hydrocele, two females became acute filarial patients and 18 subjects (13 males, five females) were asymptomatic amicrofilaraemics. Filarial antigen was detected in 36 individuals (81·2%, 27 male, nine female) comprising microfilaraemics, amicrofilaraemics and diseased. Only eight individuals (18·2%, two males, six females) remained antigen free.
H2O in metamorphism and unexpected behaviour in the preservation of metamorphic mineral assemblages
Authors: Guiraud M. , Powell R. , Rebay G.
Published: March 2003

The preservation of mineral assemblages that were fluid‐present during their prograde history is primarily related to the consumption of the fluid by growth of more hydrous minerals as the retrograde history begins. The range of behaviour relating to the preservation of mineral assemblages is examined using calculated phase diagrams for fluid‐saturated conditions, contoured for the H2O content of the mineral assemblage. At equilibrium, as a mineral assemblage crosses contours of decreasing H2O content along a pressure–temperature path, it dehydrates, the fluid being lost from the rock. If the assemblage crosses contours of increasing H2O content, the mineral assemblage starts to rehydrate using any fluid on its grain boundaries. When the rock has consumed its fluid, the resulting mineral assemblage is that preserved in the rock. Conditions relating to the preservation of mineral assemblages are discussed, and examples of the consequences of different pressure–temperature paths on preservation in a metapelitic and a metabasic rock composition are considered on phase diagrams calculated with thermocalc.
Chromium and manganese zoning in pelitic garnet and kyanite: Spiral, overprint, and oscillatory (?) zoning patterns and the role of growth rate
Authors: Yang P. , Rivers T.
Published: March 2003

X‐ray composition maps and quantitative analyses for Mn, Ca and Cr have been made for six pelitic and calc‐pelitic garnet crystals and Al, Fe and Cr analyses maps have been made for two kyanite crystals, from lower and mid/upper amphibolite facies rocks from the Grenville Province of western Labrador, using an electron microprobe analyser and a laser ablation ICP‐MS. Garnet with spiral (‘snowball’) internal fabrics (Si) has spiral zoning in major elements, implying that growth was concentrated in discrete regions of the crystal at any one time (spiral zoning). Cr zoning is parallel to Si in low amphibolite facies garnet with both straight and spiral internal fabrics, indicating that the garnet overprinted a fabric defined by Cr‐rich (mica±chlorite±epidote) and Cr‐poor (quartz±plagioclase) layers during growth (overprint zoning) and that Cr was effectively immobile. In contrast, in mid/upper amphibolite facies garnet porphyroblasts lacking Si, Cr zoning is concentric, implying that Cr diffusion occurred. Cr zoning in kyanite porphyroblasts appears superficially similar to oscillatory zoning, with up to three or four annuli of Cr enrichment and/or depletion present in a single grain. However, the variable width, continuity, Cr concentration and local bifurcation of individual annuli suggest that an origin by overprint zoning may be more likely. The results of this study explain previously observed nonsystematic Cr zoning in garnet and irregular partitioning of Cr between coexisting metamorphic mineral pairs. In addition, this study points to the important role of crystal growth rate in determining the presence or absence of inclusions and the type of zoning exhibited by both major and trace elements. During fast growth, inclusions are preferentially incorporated into the growing porphyroblast and slow diffusing elements such as Cr are effectively immobile, whereas during slow growth, inclusions are not generally included in the porphyroblast and Cr zoning is concentric.
Retrograde processes in migmatites and granulites revisited
Authors: Brown Michael
Published: March 2003

Many migmatites and granulites preserve evidence of a clockwise P–T evolution involving decompression (decrease in P) while close to the thermal peak. The extent of post‐thermal peak reaction is influenced by several factors, including: (1) the P–T path in relation to invariants in the system and the Clapeyron slopes of the equilibria; (2) the rate of cooling; and (3) the availability of fluid (H2O‐rich volatile phase or melt) for fluid‐consuming reactions. Reaction may occur between products of a prograde (increasing T) fluid‐generating reaction as the same equilibrium is re‐crossed in the retrograde (decreasing T) sense. In general, reaction reversal or ‘back reaction’ requires the P–T path to approximate isobaric heating and cooling, without significant decompression, and evolved fluid to remain within the equilibration volume. The larger the decompression segment in the P–T evolution, the more chance there is of crossing different reactions along the retrograde segment from those crossed along the prograde segment. For common pelite compositions, we may generalize by considering three pressure regimes separated by the [Spl, Ms, H2O] invariant in KFMASH (approximately 9 kbar) and the intersection of muscovite breakdown with the H2O‐rich volatile phase‐saturated solidus (approximately 4 kbar). Reaction reversal cannot occur along P–T paths that traverse around one of these points, but may occur along P–T paths confined to one of the three regimes in between. Additionally, above the solidus, melt segregation and loss potentially change the composition of the equilibration volume; and, the size of the equilibration volume shrinks with decreasing T. Since the proportion of melt to residue in the equilibration volume may change with decreasing size, the composition of the equilibration volume may change throughout the supra‐solidus part of the retrograde segment of the P–T evolution. If melt has been lost from the equilibration volume, reaction reversal may not be possible or may be only partial; indeed, the common preservation of close‐to‐peak mineral assemblages in migmatite and granulite demonstrates that extensive reaction with melt is uncommon, which implies melt isolation or loss prior to crossing potential melt‐consuming reactions. Water dissolved in melt is transported through the crust to be exsolved on crystallization at the solidus appropriate to the intrinsic a(H2O). This recycled water causes retrogression at subsolidus conditions. Consideration of the evidence for supra‐solidus decompression‐dehydration reactions, and review of microstructures that have proven controversial, such as corona and related microstructures, selvage microstructures and ‘late’ muscovite, leads to the conclusion that there is more than one way for these microstructures to form and reminds us that we should always consider multiple working hypotheses!
Experiences of assessment: using phenomenography for evaluation
Authors: Jones C. , Asensio M.
Published: March 2003

Abstract The aim of this paper is to explore the use of assessment as a tool for structuring students' experiences within a networked learning environment. It is suggested that this investigation may have a wider bearing on issues raised by the idea of aligning teaching approach with the students' approach to learning. The methods used are broadly phenomenographic and the use of this approach is proposed for the evaluation of networked learning in higher education. The work is drawn from the initial phase of a two‐year study being undertaken at Lancaster University. The choice of phenomenography as the preferred methodological approach is explained and how this is appropriate for evaluation. An emphasis is placed upon the evaluative aspects of phenomenography, its focus on varieties of experience and the relationship between approaches adopted to learning and the outcomes of learning. The example, drawn from the research, examines student approaches in relation to the declared intentions of the course designers.
Programmers: concrete women and abstract men?
Authors: McKenna P.
Published: March 2003

Abstract Sherry Turkle and Seymour Papert have identified a hands‐on and experimental ‘concrete’ approach to computer programming as feminine, and as a fully formed way of knowing how to program, rather than as either a learning style or as a stage in development. This paper differentiates between concrete styles of learning how to program, and the concrete style of programming. Learning strategy is decoupled from programming style, and the hypothesis that women are more likely than men to prefer a concrete style of programming is tested by means of examining responses to practical examples of concrete and abstract styles. The responses suggest that there is no significant difference between women and men in their attitude toward a concrete style of programming.
Students' perceptions of ICT‐related support in teaching placements
Authors: Galanouli D. , McNair V.
Published: March 2003

Abstract Recent research has shown that students' use of information and communications technology (ICT) on teaching practice is necessary for effective future use of ICT in the classroom. However, this paper reports that there are a number of factors affecting the use of ICT by student‐teachers in their school placements. All 110 student‐teachers attending one university's eight Postgraduate Certificate in Education (PGCE) courses completed a questionnaire on their attitudes to ICT in learning and teaching and their initial experiences of the application of ICT in schools. In‐depth interviews with the student‐teachers, as well as univer‐sity tutors and teachers, revealed a range of issues that reflected how student‐teachers perceive their school‐based ICT training and what they think could improve their experiences. Recommendations are offered for the improvement of the ICT school experiences for student‐teachers until teacher training is completed and improved ICT infrastructure is in place in schools. The overriding conclusion is that schools must be supported and resourced properly, and teachers must have effective ICT training, before improvements in school‐based ICT development for student‐teachers can be achieved.
Evaluating the persona effect of an interface agent in a tutoring system
Authors: Moundridou M. , Virvou M.
Published: March 2003

Abstract This paper describes the evaluation of the persona effect of a speech‐driven anthropomorphic agent that has been embodied in the interface of an intelligent tutoring system (ITS). This agent is responsible for guiding the student in the environment and communicating the system's feedback messages. The agent was evaluated in terms of the effect that it could have on students' learning, behaviour and experience. The participants in the experiment were divided into two groups: half of them worked with a version of the ITS which embodied the agent and the rest worked with an agent‐less version. The results from this study confirm the hypothesis that a pedagogical agent incorporated in an ITS can enhance students' learning experience. On the other hand, the hypothesis that the presence of the agent improves short‐term learning effects was rejected.
Diagnosing students' alternative conceptions in science
Authors: Tsai C.‐C. , Chou C.
Published: March 2003

Abstract This study described an attempt to develop a networked two‐tier test system. A two‐tier test is a two‐level multiple‐choice question that diagnoses students' alternative conceptions in science. Three networked, two‐tier test items were presented in this study. Students in Taiwan (555 14 year olds and 599 16 year olds) were asked to answer these items online. An analysis of students' answers suggested that students' alternative conceptions might be retained even after formal instruction about relevant conceptions. Moreover, their responses were related across these three two‐tier test items. Further development of the two‐tier test system will mainly focus on designing appropriate feedback and guidance that help students overcome their alternative conceptions. In this way, the networked two‐tier test system is not only a diagnostic tool, but also an effective instructional tool. This study has illuminated some innovative thoughts for the research and practice of science education.
The European Union and e‐learning: an examination of rhetoric, theory and practice
Authors: Hodgson V.E.
Published: March 2003

Abstract The paper examines the impact that new technology has had upon the rhetoric, theory and practice of trans‐national educational collaboration within Europe. The paper first looks very generally at the way e‐learning has become a strong part of the educational rhetoric of the EU. Some of the different models found in the literature for describing online courses and teaching and learning approaches used within distance education are then described. These models, however, for the most part apply to courses that are offered by single generally specialist distance education providers. In contrast, the ODL/Minerva projects supported by the European Commission's Socrates programme are relatively unusual in that they have as a starting point a consortium of trans‐national partners engaged in a common educational venture. Consequently, the second part of the looks at some of the models generated within the ODL action. This is followed by descriptions of the work of three ODL projects, each of which differ in orientation and approach. It is argued that the dimensions on which the three projects most significantly differ are not so much according to the models already described in the first part of the paper but is more related to their assumptions about how comparative knowledge is viewed and the kind of discourse from which knowledge and learning is generated and the dialogical practices used to support this.
Mapping distributions of chromosomal forms of Anopheles gambiae in West Africa using climate data
Authors: Bayoh M. N. , Thomas C. J. , Lindsay S. W.
Published: March 2003

Abstract. The mosquito Anopheles gambiae Giles sensu stricto (Diptera: Culicidae), the principal vector of malaria in West Africa, comprises several chromosomal forms (e.g. Bissau, Forest, Mopti, Savanna) associated with climatic zones. Here we show how climate data can be used to map the geographical distribution of these chromosomal forms. The climate at 144 sites surveyed for mosquitoes in West Africa between 1971 and 92 was determined using computerized climate surfaces. Forest and Bissau forms occurred at relatively wet sites: median annual precipitation 1325 mm and 1438 mm, respectively, interquartile ranges (IQR) 1144–1858 mm and 1052–1825 mm), whilst the Mopti form was found at dry sites (annual 938 mm, IQR 713–1047 mm) and the Savanna form at sites intermediate between the wet and dry forms (annual 1067 mm, IQR 916–1279). Logistic regression analyses of the climate variables were carried out on a stratified random sample of half the sites. The resulting models correctly classified over 80% of the sites for presence or absence of each chromosomal form. When these models were tested against excluded sites they were also correct at over 80% of sites. The combined data produced models that were correct at over 86% of sites. Mean annual precipitation, evapotranspiration, minimum temperature and maximum temperature were the most important climate variables correlated with the distribution of these forms of An. gambiae. We used the logistic models to map the distribution of each chromosomal form within the reported range for An. gambiae s.s. in West Africa employing a geographical information system. Our maps indicate that each chromosomal form favours particular climate envelopes in well‐defined ecoclimatic zones, although these forms are sympatric at the edges of their ranges. This study demonstrates that climate can be used to map the distribution of chromosomal forms of insects across large areas.
Impact of untreated bednets on prevalence of Wuchereria bancrofti transmitted by Anopheles farauti in Papua New Guinea
Authors: Bockarie M. J. , Tavul L. , Kastens W. , Michael E. , Kazura J. W.
Published: March 2003

Abstract Despite the growing evidence that insecticide‐treated mosquito nets reduce malaria morbidity and mortality in a variety of epidemiological conditions, their value against lymphatic filariasis infection and disease is yet to be established. The impact of untreated bednets on the prevalence of Wuchereria bancrofti (Cobbold) (Nematoda: Filarioidea) infection and disease was investigated on Bagabag island in Papua New Guinea, where both malaria and filariasis are transmitted by the same vector mosquitoes of the Anopheles punctulatus Dönitz group (Diptera: Culicidae). Community‐wide surveys were conducted recording demographic characteristics including bednet usage. Physical examinations for hydrocoele and lymphoedema were performed and blood samples assessed for filarial and malaria parasites. Mosquitoes were sampled using the all‐night landing catch method and individually dissected to determine W. bancrofti infection and infective rates. Bednet usage among residents was 61% and the mean age of users (25.6 years) was similar to non‐users (22.5 years). Anopheles farauti Laveran was the only species were found to contain filarial larvae: 2.7% infected (all stages), 0.5% infective (L3). The overall W. bancrofti microfilaraemia and antigenaemia rates were 28.5% and 53.1%, respectively. Bednet users had lower prevalence of W. bancrofti microfilaraemia, antigenaemia and hydrocoele rates than non‐users. In comparison, untreated bednets had no effect on the prevalence and intensity of Plasmodium falciparum and P. vivax infections. The impact of bednet usage on rates of microfilaraemia and antigenaemia remained significant even when confounding factors such as age, location and sex were taken into account, suggesting that untreated bednets protect against W. bancrofti infection.
Evaluation of the effects of swainsonine, captopril, tangeretin and nobiletin on the biological behaviour of brain tumour cells in vitro
Authors: Rooprai H. K. , Kandanearatchi A. , Maidment S. L. , Christidou M. , Trillo‐Pazos G. , Dexter D. T. , Rucklidge G. J. , Widmer W. , Pilkington G. J.
Published: March 2003

Although intrinsic tumours of the brain seldom metastasize to distant sites, their diffuse, infiltrative–invasive growth within the brain generally precludes successful surgical and adjuvant therapy. Hence, attention has now focused on novel therapeutic approaches to combat brain tumours that include the use of anti‐invasive and anti‐proliferative agents. The effect of four anti‐invasive agents, swainsonine (a locoweed alkaloid), captopril (an anti‐hypertensive drug), tangeretin and nobiletin (both citrus flavonoids), were investigated on various parameters of brain tumour invasion such as matrix metalloproteinase (MMP) secretion, migration, invasion and adhesion. A standard cytotoxicity assay was used to optimize working concentrations of the drugs on seven human brain tumour‐derived cell lines of various histological type and grade of malignancy. A qualitative assessment by gelatin zymography revealed that the effect of these agents varied between the seven cell lines such that the low grade pilocytic astrocytoma was unaffected by three of the agents. In contrast, downregulation of the two gelatinases, MMP‐2 and MMP‐9 was seen in the grade 3 astrocytoma irrespective of which agent was used. Generally, swainsonine was the least effective whereas the citrus flavonoids, particularly nobiletin, showed the greatest downregulation of secretion of the MMPs. Furthermore, captopril and nobiletin were most efficient at inhibiting invasion, migration and adhesion in four representative cell lines (an ependymoma, a grade II oligoastrocytoma, an anaplastic astrocytoma and a glioblastoma multiforme). Yet again, the effects of the four agents varied between the four cell lines. Nobiletin was, nevertheless, the most effective agent used in these assays. In conclusion, the differential effects seen on the various parameters studied by these putative anti‐invasive agents may be the result of interference with MMPs and other mechanisms underlying the invasive phenotype. From these pilot studies, it is possible that these agents, especially the citrus flavonoids, could be of future therapeutic value. However, further work is needed to validate this in a larger study.
Apoptosis in amyotrophic lateral sclerosis: a review of the evidence
Authors: Sathasivam S. , Ince P. G. , Shaw P. J.
Published: March 2003

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease primarily affecting the upper and lower motor neurones of the central nervous system. Recently, a lot of interest has been generated by the possibility that a mechanism of programmed cell death, termed apoptosis, is responsible for the motor neurone degeneration in this condition. Apoptosis is regulated through a variety of different pathways which interact and eventually lead to controlled cell death. Apart from genetic regulation, factors involved in the control of apoptosis include death receptors, caspases, Bcl‐2 family of oncoproteins, inhibitor of apoptosis proteins (IAPs), inhibitors of IAPs, the p53 tumour suppressor protein and apoptosis‐related molecules. The first part of this article will give an overview of the current knowledge of apoptosis. In the second part of this review, we will examine in detail the evidence for and against the contribution of apoptosis in motor neurone cell death in ALS, looking at cellular‐, animal‐ and human post‐mortem tissue‐based models. In a chronic neurodegenerative disease such as ALS, conclusive evidence of apoptosis is likely to be difficult to detect, given the rapidity of the apoptotic cell death process in relation to the relatively slow time course of the disease. Although a complete picture of motor neurone death in ALS has not been fully elucidated, there is good and compelling evidence that a programmed cell death pathway operates in this disorder. The strongest body of evidence supporting this comes from the findings that, in ALS, changes in the levels of members of the Bcl‐2 family of oncoproteins results in a predisposition towards apoptosis, there is increased expression or activation of caspases‐1 and ‐3, and the dying motor neurones in human cases exhibit morphological features reminiscent of apoptosis. Further supporting evidence comes from the detection of apoptosis‐related molecules and anti‐Fas receptor antibodies in human cases of ALS. However, the role of the p53 protein in cell death in ALS is at present unclear. An understanding of the mechanism of programmed cell death in ALS may provide important clues for areas of potential therapeutic intervention for neuroprotection in this devastating condition.
The National NeuroAIDS Tissue Consortium:a new paradigm in brain banking with an emphasis on infectious disease
Authors: Morgello S. , Gelman B. B. , Kozlowski P. B. , Vinters H. V. , Masliah E. , Cornford M. , Cavert W. , Marra C. , Grant I. , Singer E. J.
Published: March 2003

The National NeuroAIDS Tissue Consortium (NNTC) was founded in 1998, in response to the scientific need for well‐characterized central nervous system (CNS) and peripheral nervous system (PNS) tissues and fluids from HIV‐infected individuals. In addition to performing the routine functions of non‐transplant anatomic tissue banks, the Consortium offers a unique model for the integration of independent research entities in order to provide well‐characterized tissues and fluids for the international research community. Herein, we describe the structure of the Consortium, pointing out the inherent strengths of linking together multiple independent sites for the purpose of banking HIV‐infected nervous system tissues. We describe the neuropathology protocol that was adopted and successfully implemented at the four participating banks of the Consortium.
Candida attachment to oral epithelium
Authors: Vitkov L. , Krautgartner W. D. , Hannig M. , Weitgasser R. , Stoiber W.
Published: March 2003

Inflamed oral mucosa biopsies from patients with thrush and high candidal density were observed in a transmission electron microscope (TEM) using ultra‐histochemical staining with ruthenium red for glycocalyx visualization. Fimbriae comprising the glycocalyx and enabling yeast adhesion to epithelial cells were clearly visualized by ruthenium red. All internalized portions of the yeast walls were devoid of glycocalyx, indicating that the growing tips of the hyphae mechanically penetrated the host cells. The attachment of Candida occurred in two ways: by fimbria‐mediated adhesion enabling colonization of the epithelial surface, and by invasion of the superficial epithelial cells via hyphae. As the interaction between adhesin receptors and adhesins stimulates the production of proinflammatory cytokines, Candida adhesion itself is assumed to induce mucosal inflammation.
Cariogenic traits in xylitol‐resistant and xylitol‐sensitive mutans streptococci
Authors: Assev S. , Stig S. , Scheie A. Aa.
Published: March 2003

Long‐term xylitol consumption leads to the emergence of xylitol‐resistant (X‐R) mutans streptococci. The aim of the present study was to compare cariogenic traits in X‐R and xylitol‐sensitive (X‐S) strains. Six strains of mutans streptococci, three X‐R and three X‐S strains, were studied. Xylitol resistance and sensitivity were confirmed by growth in xylitol‐supplemented media. Acid production from glucose or fructose or uptake of xylitol was initiated by adding 14C‐labelled glucose, fructose or xylitol to bacterial suspensions. The resultant metabolites were identified by HPLC. Lactate was the major metabolite from glucose, whether the bacteria were grown in the presence or the absence of xylitol. Lactate production per colony‐forming unit was lower in X‐S cells than in X‐R cells. Fructose was metabolized by both X‐R and X‐S cells. Both X‐R and X‐S cells took up xylitol, but xylitol‐5‐P was detected in X‐S cells only. Total polysaccharides were measured through production of C14‐labelled ethanol‐insoluble polymers from [U14‐C]‐sucrose. No difference in polysaccharide production was found between X‐R and X‐S cells. The present study thus does not support the contention that X‐R are less cariogenic than X‐S mutans streptococci.
Autopsy case of the cerebellar form of progressive multifocal leukoencephalopathy without immunodeficiency
Authors: Arai Yoshifumi , Tsutsui Yoshihiro , Nagashima Kazuo , Shinmura Yuichiro , Kosugi Tomoki , Wakai Masakazu , Nishikage Hirofumi , Yamamoto Junnosuke
Published: March 2003

A case of the cerebellar form of progressive multifocal leukoencephalopathy (PML) without remarkable immune depression or immune deficiency is reported here. The patient was a 74‐year‐old‐woman who had complications of chronic renal failure and renal anemia for several years. Seven months before her death she had symptoms of general fatigue, gait disturbance and articulation disorder. During her hospitalization period her neurological disorder gradually progressed irreversibly with failure of consciousness and she died of respiratory failure. She did not have remarkable clinical signs of immunodeficiency nor did she receive immunosuppressive therapy. Clinically she had not been diagnosed with PML. At the post‐mortem examination different degrees of demyelination were observed in the brain white matter: diffuse and severe in the cerebellum, moderate and coalescent in the brainstem, and light and patchy in the cerebrum. JC virus antigen‐positive cells were frequently observed in the demyelinated lesions in the cerebrum and sometimes observed in the brainstem, but were rarely found in the cerebellum. These findings suggest that PML lesions may be present with different degrees of demyelination that are inversely correlated with the number of JC virus‐infected cells. This fact should be considered when evaluating the brain biopsies of PML patients.
Skin cleansing in children
Authors: Gelmetti C
Published: March 2003

The problems of skin cleansing in infants have been re‐evaluated in recent years on the basis of current understanding of cosmetology and skin physiology. The anatomical and functional peculiarities of infant’s skin have been elucidated and, although it is known that the barrier function is established at birth in normal babies, it remains the case that children’s skin is more delicate and therefore more prone to irritant and allergic contact dermatitis. These factors determine the choice of cleansing agents during infancy. The products available on the market differ markedly. Indeed detergents, bath oils, bath powders, due to their distinctive properties, have different indications and different benefits. The method of cleansing the skin, i.e. bathing or showering, is also important. The frequency of cleansing should take into account the age and the degree of exposure to pollutants. For special purposes, e.g. impetiginized dermatoses, antiseptics such as potassium permanganate or chlorhexidine can be added to the water in appropriate concentrations. The ideal paediatric detergent should be very mild to avoid irritant dermatitis, and very simple to avoid allergic dermatitis.
Small changes in the activity of chloroplastic NADP+‐dependent ferredoxin oxidoreductase lead to impaired plant growth and restrict photosynthetic activity of transgenic tobacco plants
Authors: Hajirezaei Mohammad‐Reza , Peisker Martin , Tschiersch Henning , Palatnik Javier F. , Valle Estela M. , Carrillo Néstor , Sonnewald Uwe
Published: March 2003

A ferredoxin‐NADP+ oxidoreductase (FNR) cDNA from tobacco (Nicotiana tabacum cv. Samsun) was cloned and sequenced. Comparison of the deduced amino acid sequence revealed high identity to FNR proteins from Capsicum annuum, Pisum sativum, Spinacia oleracea and Vicia faba. Transgenic tobacco plants were generated that constitutively express the FNR cDNA in reverse orientation between the CaMV 35S promoter and the polyadenylation signal of the octopine synthase gene. Plants expressing the FNR antisense gene showed lower levels of FNR mRNA and protein accumulation, which was paralleled by a decrease in FNR activity. As a consequence, NADPH levels declined whereas NADP+ levels increased, leading to an unaltered NADP(H) pool. Growth rates, chlorophyll content and net CO2 uptake rates at high and low irradiances were strongly reduced in FNR antisense tobacco plants. These changes were accompanied by an over‐reduced state of P700 as estimated by absorption changes at 820 nm. FNR control coefficients determined for the photosynthetic rate at saturating (CR = 0.94) and limiting (CR = 0.70) light conditions revealed a prominent role of this reductase in the regulation of photosynthesis.
Entopically additive expression of GLABRA2 alters the frequency and spacing of trichome initiation
Authors: Ohashi Yohei , Oka Atsuhiro , Ruberti Ida , Morelli Giorgio , Aoyama Takashi
Published: March 2003

GLABRA2 (GL2)/ATHB‐10 encodes a homeodomain protein that belongs to the homeodomain‐leucine zipper family. Mutant studies have revealed that this gene is involved in trichome, root‐hair and seed‐coat development. We used reverse genetics to investigate the role of GL2 in trichome development. A transgene consisting of a GL2‐coding fragment preceded by the cauliflower mosaic virus 35S promoter (35S::GL2) did not complement defects in the gl2‐1 mutant. In the wild‐type genetic background, 35S::GL2 caused gl2‐mutant‐like and scarcely viable phenotypes, suggesting that ectopic overexpression of GL2 interrupts endogenous GL2 function in trichome development and is toxic to plants. On the other hand, another GL2 transgene containing the GL2 promoter (pGL2::GL2) complemented the gl2‐1 mutation. Entopically additive expression of GL2 by introduction of pGL2::GL2 in the wild‐type genetic background noticably increased the number of trichomes and induced production of adjacent trichomes. Consistent with this result, gl2‐1/+ heterozygous leaves, whose GL2 expression was expected to decrease, had fewer trichomes than +/+ leaves. These results indicate that GL2 quantitatively regulates the frequency of trichome initiation and is involved in determining trichome spacing.
Restoration of stamen development and production of functional pollen in an alloplasmic CMS tobacco line by ectopic expression of the Arabidopsis thaliana SUPERMAN gene
Authors: Bereterbide Agnès , Hernould Michel , Farbos Isabelle , Glimelius Kristina , Mouras Armand
Published: March 2003

The alloplasmic male‐sterile tobacco line Nta(rep)S, combining the nucleus of Nicotiana tabacum with the cytoplasm of Nicotiana repanda, exhibits cadastral‐type anomalies due to a fusion of several stamens with the pistil. These anomalies share similarities with Arabidopsis superman mutants. SUPERMAN (SUP) is a cadastral gene controlling the boundary between whorls 3 (androecium) and 4 (gynoecium). Thus we hypothesized that the expression of the tobacco SUP orthologue might be impaired in the alloplasmic Nta(rep)S line, and that the deficiency could be complemented by the Arabidopsis SUP gene. Here we show that the ectopic expression of SUP in the alloplasmic male‐sterile tobacco line Nta(rep)S significantly increases the frequency of flowers possessing free stamens, inducing the recovery of a proper structure for whorls 3 and 4. Furthermore, flowers of transgenic plants show a significant improvement of the morphology of stamens, and more particularly of the anthers, which are able to produce few but functional pollen. The data show that ectopic expression of Arabidopsis SUP reactivates the regulatory cascade of anther development. The plausible causes of the developmental defects of anthers in the alloplasmic male‐sterile tobacco line are discussed in relation to the model of regulation of the Arabidopsis SUP gene.
Avulsed permanent incisors: knowledge and attitudes of primary school teachers with regard to emergency management
Authors: Blakytny C. , Surbuts C. , Thomas A. , Hunter M. L.
Published: March 2003

Objectives. This study was designed to examine the knowledge and attitudes of primary school teachers with regard to the emergency management of avulsed permanent incisors.

Design. Data were collected by self‐administered questionnaire.

Setting. The study was conducted in primary schools lying within a 2‐mile radius of the University Dental Hospital, Cardiff.

Sample and methods. A total of 388 teachers in 31 participating schools were asked to complete a questionnaire, which was subsequently collected by two of the authors (CS and AT).

Results. Two hundred and seventy‐four teachers returned completed questionnaires, a response rate of 70·6%. One hundred and eighty‐one respondents (60·1%) had received no advice about the emergency management of dental avulsion. Of the 133 teachers (48·5%) who possessed a first aid certificate, 39 (29·3%) had been given relevant advice as part of this training. Less than one‐third of respondents (85 (31%)) cited an optimum extra‐oral time of 30 min or less, with only 43 (15·7%) considering that this should be 10 min or less. However, 125 (45·6%) knew milk to be the best transport medium. Two hundred and four teachers (74·5%) stated that they would not be prepared to replant an avulsed tooth themselves, 133 (80%) basing this decision on lack of expertise and training. Two hundred and sixty‐two teachers (95·6%) expressed a desire for further information.

Conclusions. The majority of respondents possessed, at best, rudimentary knowledge of the emergency management of dental avulsion. Teachers, and other individuals who supervise children in schools, should receive simple instruction in dental first aid.