bluuebunny/crossref_metadata_2025 huggingface dataset:
Subunit specificity and interaction domain between GABAA receptor‐associated protein (GABARAP) and GABAA receptors
Authors: Nymann‐Andersen Jesper , Wang Hongbing , Chen Li , Kittler Josef T. , Moss Stephen J. , Olsen Richard W.
Published: March 2003

GABARAP (GABAA receptor‐associated protein) interacts with both microtubules and GABAA receptors in vitro and in␣vivo and is capable of modulating receptor channel kinetics. In this study, we use the intracellular loop of 15 GABAA receptor subunits to show that the interaction between GABARAP and GABAA receptor is specific for the gamma subunits. Pharmacological characterization of proteins purified by GABARAP affinity column indicates that native GABAA receptors interact with GABARAP. Quantitative yeast two‐hybrid assays were used to identify the interaction domain in the γ2 subunit for GABARAP binding, and to identify the interaction domain in GABARAP for GABAA receptor binding. A peptide corresponding to the GABARAP interaction domain in the γ2 subunit was used to inhibit the interaction between GABARAP and the γ2 subunit. In addition, the ability of GABARAP to promote cluster formation of recombinant receptors expressed in QT‐6 fibroblasts was inhibited by a membrane‐permeable form of this peptide in a time‐dependent manner. The establishment of a model for GABARAP‐induced clustering of GABAA receptors in living cells and the identification of subunit specificity and interaction domains in the interaction between GABARAP and GABAA receptors is a step in dissecting the function of GABARAP in GABAA receptor clustering and/or targeting.
Non‐homologous DNA end joining in the mature rat brain
Authors: Ren Keqin , De Ortiz Sandra Peña
Published: March 2003

Recent evidence suggests that DNA double strand breaks (DSBs) are introduced in neurons during the course of normal development, and that repair of such DSBs is essential for neuronal survival. Here we describe a non‐homologous DNA end joining (NHEJ) system in the adult rat brain that may be used to repair DNA DSBs. In the brain NHEJ system, blunt DNA ends are joined with lower efficiency than cohesive or non‐matching protruding ends. Moreover, brain NHEJ is blocked by DNA ligase inhibitors or by dATP and can occur in the presence or absence of exogenously added ATP. Comparison of NHEJ activities in several tissues showed that brain and testis share similar mechanisms for DNA end joining, whereas the activity in thymus seems to utilize different mechanisms than in the nervous system. The developmental profile of brain NHEJ showed increasing levels of activity after birth, peaking at postnatal day 12 and then gradually decreasing along with age. Brain distribution analysis in adult animals showed that NHEJ activity is differentially distributed among different regions. We suggest that the DNA NHEJ system may be utilized in the postnatal brain for the repair of DNA double strand breaks introduced within the genome in the postnatal brain.
Metabolism of reduced and inorganic sulphur in pea cotyledons and distribution into developing seedlings
Authors: Herschbach Cornelia , Pilch Birgit , Tausz Michael , Rennenberg Heinz , Grill Dieter
Published: March 2003

Sulphur export and redistribution from the cotyledons of pea (Pisum sativum) seedlings was investigated to determine the role of cotyledons as a sulphur source during root–shoot axis development.

 Thiols and sulphate were analysed using standard biochemical techniques, and 35S fed to cotyledons by injection.

 After 35S‐cysteine injection, c. 50% of the labelled S in the cotyledon was metabolized to 35S‐sulphate. This reaction was partly inhibited by aminooxyacetic acid, an inhibitor of cysteine‐desulfhydrase. After 35S‐sulphate application, c. 1% of the radiolabel was found in cysteine and glutathione in the cotyledon. After 2 h, c. 20% of the 35S was transported into the root–shoot axis independently of whether 35S‐sulphate or 35S‐cysteine was injected into the cotyledon. After 4 h, 40% of 35S was found outside the cotyledon.

 Cotyledons of pea seedlings are capable of sulphate assimilation and cysteine degradation. Both sulphate and reduced sulphur were allocated from the cotyledons to the developing tissues of the pea seedlings.
Stomatal control by chemical signalling and the exploitation of this mechanism to increase water use efficiency in agriculture
Authors: Davies William J. , Wilkinson Sally , Loveys Brian
Published: March 2003

Stomatal behaviour of plants in drying soil can be regulated by (long distance) chemical signals that provide the shoot with some measure of water availability. Although much emphasis has been placed on the plant hormone abscisic acid (ABA) as a central component of the signalling process, soil drying will modify the delivery to the shoot of a range of potential chemical signals. Here we consider the role that changes in the xylem sap pH might play in determining the access that ABA has to sites of action on the guard cells. We also show how redistribution of inorganic ions between different compartments in the leaf (localized chemical signalling) can provide sensitive control of stomata and water loss in response to potentially damaging changes in leaf temperature. Partial root zone drying is an irrigation technique that has been developed to allow exploitation of the plant’s long distance signalling system. When the system is optimized, stomatal behaviour, shoot water status and leaf growth can be regulated such that water use efficiency (fruit yield/water used) can be significantly increased. We show how an understanding of the drought stress physiology of the whole plant can lead to substantial saving of irrigation water in agriculture.
Determination of Stress Concentration Factors for Holes in Cylinders Using Thermoelastic Stress Analysis
Authors: Quinn S. , Dulieu‐Barton J. M.
Published: March 2003

Thermoelastic stress analysis is used to obtain the stress concentration factors (SCFs) from a variety of circular holes in cylinders. The cylinders are loaded in uniaxial tension, uniaxial compression and a combination of bending and compression. Firstly, radial holes are investigated and the results from the thermoelastic data obtained by the SPATE equipment are compared with previous experimental and numerical work. SCFs are then obtained from offset, oblique and offset–oblique holes using the Deltatherm system. The effect of hole obliquity and direction of applied load relative to the hole geometry are discussed in detail. Finally, the results from the cylinders are compared with predictions of the SCFs in cylinders from a previous study of oblique holes in flat plates.
Isolation of human scFv antibody fragments against ABO blood group antigens from a phage display library
Authors: Santos‐Esteban E. , Curiel‐Quesada E.
Published: March 2003

Background and Objectives

Phage display has proven very useful for the isolation of antibodies against a number of antigens. We used this technology to isolate scFv antibody fragments against A and B red blood cell antigens.

Materials and Methods

Phages from a phage display library were selected using unmodified red blood cells as a source of antigen. Bound phages were absorbed onto cells lacking the antigen of interest and used to infect Escherichia coli cells. Phages were rescued and assayed for specificity by enzyme‐linked immunosorbent assay (ELISA).

Results

After several rounds of panning and subtraction on red blood cells, one anti‐A and one anti‐B human scFv antibody fragments were isolated.

Conclusion

Isolation of anti‐A and anti‐B scFv antibody fragments on whole cells is an alternative method of obtaining antibodies against native cell‐surface antigens.
Human platelet antigen‐1a antibodies induce the release of the chemokine RANTES from human platelets
Authors: Dettke M. , Dreer M. , Höcker P. , Panzer S.
Published: March 2003

Background and Objective

Binding of human platelet antigen‐1a (HPA‐1a)‐specific antibodies to target platelets can trigger platelet activation and mediator release. Here we tested the effect of HPA‐1a antibody‐containing sera on platelet release of the chemokine RANTES (regulated on activation, normal, T‐cell expressed, and presumably secreted) in vitro.

Patients and Methods

HPA‐1a‐containing sera obtained from 11 mothers delivered of an infant with neonatal alloimmune thrombocytopenia (NAIT) and from six patients with post‐transfusion purpura (PTP) were incubated with HPA‐1a/a target platelets. Antibody‐induced release of soluble RANTES was determined by enzyme‐linked immunosorbent assay (ELISA).

Results

A significant release of soluble RANTES was induced by four out of the 17 sera. Two out of the four reactive sera were obtained from mothers who were delivered of a baby with NAIT and the remaining two sera were from patients with PTP. Chemokine release was specific for binding of anti‐HPA‐1a to the platelet membrane, as none of the reactive sera induced the release of soluble RANTES when incubated with HPA‐1b/b platelets. The blockade of platelet‐expressed Fc gamma receptor type II (FcγRII) inhibited anti‐HPA‐1a‐mediated RANTES release when incubated with the reactive sera of patients with NAIT, but not when platelets were incubated with sera of patients with PTP.

Conclusion

Our findings suggest that anti‐HPA‐1a antibody‐induced release of platelet‐derived RANTES can play a role in adverse reactions in alloimmunized patients.
Hydrothermal alteration of late‐ to post‐tectonic Lyon Mountain Granitic Gneiss, Adirondack Mountains, New York: Origin of quartz–sillimanite segregations, quartz–albite lithologies, and associated Kiruna‐type low‐Ti Fe‐oxide deposits
Authors: Mclelland J. , Morrison J. , Selleck B. , Cunningham B. , Olson C. , Schmidt K.
Published: March 2003

Quartz–sillimanite segregations, quartz–albite lithologies (Ab95–98), and Kiruna‐type low‐Ti iron‐oxide deposits are associated with late‐ to post‐tectonic (c. 1055 Ma) leucogranites of Lyon Mountain Gneiss (LMG) in the Adirondack Mountains, New York State. Most recent interpretations of these controversial features, which are global in occurrence, favour hydrothermal origins in agreement with results presented here.

Field relations document that quartz–sillimanite veins and nodules cut, and therefore post‐date, emplacement of host LMG leucogranites. Veins occur in oriented fracture networks, and aligned trains of nodules are interpreted as disrupted early veins. Late dykes of leucogranite cut veins and nodules demonstrating formation prior to terminal magmatism. Veins and nodules consist of sillimanite surrounded by quartz that commonly embays wall‐rock feldspar indicating leaching of Na and K from LMG feldspar by acidic hydrothermal fluids. Subsequent, and repeated, ductile flow disrupted earlier veins into nodular fragments but produced little grain shape fabric.

Geochemical and petrographic studies of quartz–albite rock indicate that it formed through metasomatic replacement (albitization) of LMG microperthite by sodic hydrothermal fluids that resulted in diagnostic checkerboard albite. Low‐Ti iron‐oxide ores are commonly associated with the quartz–albite sub‐unit, and it is proposed that hydrothermal fluids related to albitization transported Fe as well. The regional extent of sodic alteration suggests large quantities of surface‐derived hydrothermal fluids. Fluid inclusion and oxygen isotope data are consistent with high temperature, regionally extensive fluids consisting primarily of evolved surface‐derived brines enriched in Na and Cl. Quartz–sillimanite veins and nodules, which are significantly more localised phenomena and require acidic fluids, were most likely formed from local magmatic fluids in the crystallizing carapaces of LMG plutons.
Occurrence of calcite in Sanbagawa pelitic schists: implications for the formation of garnet, rutile, oligoclase, biotite and hornblende
Authors: Goto A. , Banno S. , Higashino T. , Sakai C.
Published: March 2003

The frequency of occurrence of minerals in 1876 samples of Sanbagawa pelitic schist in central Shikoku is summarized on the basis of microscopic observation accompanied, in part, by use of an electron microprobe. All samples contain quartz, plagioclase, phengite, chlorite and graphite. More than 90% of samples contain clinozoisite, titanite and apatite. Garnet is present in 95% of samples from the garnet zone, and biotite is present in 64% of samples from the albite‐biotite zone. Calcite is found in about 40% of samples of the pelitic schist collected from outcrop, but occurs in 95% of the pelitic schist from drill cores. Calcite was apparently ubiquitous in the pelitic schist during the Sanbagawa metamorphism, but must have been dissolved recently by the action of surface or ground water. The mineral assemblages of the Sanbagawa pelitic schist have to be analyzed in the system with excess calcite, quartz, albite (or oligoclase), clinozoisite, graphite and fluid that is composed mainly of H2O, CO2 and CH4. In the presence of calcite, reactions that produce garnet, rutile, oligoclase, biotite and hornblende, some of which define isograds of the metamorphic belt, should be written as mixed volatile equilibria that tend to take place at lower temperature than the dehydration reactions that have been proposed. The presence of calcite in pelitic schist suggests that fluid composition is a variable as important in determining mineral assemblages as pressure and temperature. Thus Ca‐bearing phases must be taken into account to analyze the phase relations of calcite‐bearing pelitic schist, even if CaO content of Sanbagawa pelitic schist is low. As calcite is a common phase, the mineral assemblages of the biotite zone pelitic schist may contravene the mineralogical phase rule and warrant further study.
An object‐oriented software life cycle of an intelligent tutoring system
Authors: Virvou M. , Tsiriga V.
Published: March 2003

Abstract  This paper describes the application of an object‐oriented model of life cycle in the development of an intelligent tutoring system for secondary students in the domain of algebraic powers. The system is called EasyMath and has been developed using the Rational Unified Process, which is an object‐oriented process proposed for use with the Unified Modelling Language. The Rational Unified Process supports multiple recursions of the phases of the software life cycle. This has been enriched to include empirical studies and formative evaluations appropriate for knowledge‐based educational software.
Perspectives on the relationships between ICT and assessment
Authors: McFarlane A.
Published: March 2003

Abstract  There are at least three perspectives on ICT in schools which influence policy and practice. This paper considers the relationship between each of these perspectives: as a tool, as learning support and as revolutionary agent, and the relationship of each to assessment. It proposes that ultimately what determines the role ICT plays in school‐based learning depends on the value attributed to learning outcomes. While national assessments continue to reward specified content knowledge above knowledge building abilities, the use of ICT will continue to cause tensions in the classroom.
The computer as a Trojan Horse
Authors: Boyle M.
Published: March 2003

Abstract This paper reports on a study of boys in an Australian secondary school who were under achieving in school mathematics. The subjects were asked to develop computing software to teach fellow students about aspects of Ancient Egyptian mathematics. The paper reports four example case studies of the experience of the subjects during the course of the intervention. The paper examines the use of computing software development as a vehicle for the incidental learning of mathematical technique and for changes in attitude towards mathematics. Four different mathematical activities are reported in the case studies with a screen‐dump of the subjects work included as an illustrative example.
The effect of questioning on concept learning within a hypertext system
Authors: Howard‐Jones P.A. , Martin R.J.
Published: March 2003

Abstract Two studies report upon the effect of asking learners to answer questions when learning in a hypertext environment, even when no immediate feedback is given to learners about the appropriateness of their responses. Such questions may be useful as a means to induce responses that can be used to monitor learning, but here the hypothesis was investigated that their inclusion would also improve learning directly. In the first study, 80 student teachers answered embedded multiple‐choice questions that encouraged analysis of examples. Concept learning achieved using this environment was significantly reduced when compared with an environment requiring no such responses. In the second study, a cohort of 68 students were asked to summarise the information illustrated by the examples. Here, learning was significantly improved as compared with the no‐response condition.
Conceptualising work activity for CAL systems design
Authors: Mwanza D.
Published: March 2003

Abstract  As computing technology has increasingly become relevant to people's everyday lives, emphasis is being placed on ensuring Computer Assisted Learning (CAL) tools support users in ways that are meaningful to them. This requirement has highlighted the need to understand the complex and often dynamic social and cultural organisation of collaborating individuals in context. Here, the aim is to conceptualise the natural flow and evolution of work practices so as to inform the design of these systems. This paper reports on empirical findings of an investigation into the design requirements for a CAL system for supporting knowledge sharing activities in an organisation.
A web‐based learning and assessment system to support flexible education
Authors: Gardner L. , Sheridan D. , White D.
Published: March 2003

Abstract At a time where increased costs and resource constraints are experienced by many tertiary institutions globally, the pressure to find alternative methods to deliver teaching and assessment increases. Whilst the individual learning experience is paramount, the need to manage the numbers, resources and assessment provide an administrative overhead and headache to all teaching staff. With this predicament in mind a computer‐supported learning system (CECIL) was developed. It is a web‐based teaching and learning resource and administration system. This paper describes the CECIL structure and discusses the potential benefits that a university‐wide resource management system may have in terms of the educational flexibility and resource sharing.
A preliminary evaluation of a web‐mediated ‘School for All’
Authors: Young S.S.C. , Chan T.W. , Lin C.B.
Published: March 2003

Abstract  School for All
in the
EduCities programme is an innovative project funded by both the Ministry of Education and the National Science Council of Taiwan. The project aims to challenge the rationale of conventional education: only teachers teach and students learn. This paper reports on a project which investigated if anyone who is prepared to engage in web education can teach with the aid of Information Technology. This was done by holding contests of web courses. In the first contest, 290 courses were registered for the competition and were evaluated in several phases. Consequently 15 outstanding online teachers were selected for an award. The purpose of this paper is to document the study and to report the preliminary results that include the characteristics of the outstanding online teachers, such as age, occupation and pedagogical strategy.
Learning within incoherent structures: the space of online discussion forums
Authors: Thomas M.J.W.
Published: March 2003

Abstract  Online discussion forums are an increasingly common use of new information and communication technologies in education. As a tool for promoting conversational modes of learning, it has been suggested that online discussion forums can lead to enhanced learning outcomes for students. However, there is a need to explore further the implications of the highly mediated nature of computer–based interaction on student learning within these virtual learning environments. This paper presents results from a detailed study of students' learning outcomes and patterns of interaction within an online discussion forum. The findings suggest that the typical nonlinear branching structure of online discussion may be insufficient for the realisation of truly conversational modes of learning. The paper discusses the implications of these findings in relation to students' learning.
Egg hatching of mosquitoes Aedes caspius and Ae. vittatus stimulated by water vibrations
Authors: Roberts D. M.
Published: March 2003

Abstract. Simple laboratory experiments with eggs of wild‐caught Aedes caspius (Pallas) and Aedes vittatus (Bigot) mosquitoes (Diptera: Culicidae) demonstrated that egg hatch rates (i.e. percentage hatching daily) increased significantly in response to water vibrations caused by finger‐tip drumming on containers of submerged eggs. When disturbed by daily vibrations for only 30 s, eggs hatched sooner than when they remained flooded or were periodically drained and reflooded without agitation. For autogenous Ae. caspius from saltmarsh, egg hatch rates were three‐ to four‐fold greater for groups of 50 eggs than for solitary eggs, possibly due to chemicals (functional kairomones) emanating from other eggs or larvae. For anautogenous Ae. vittatus from freshwater rock‐pools, tapping the container daily (for 30 s each 2 h in 8 h) hatched 93% of eggs, compared with only 42% hatch of eggs agitated only when first flooded or 55% hatch of eggs dried and reflooded three times during 17 days without other disturbance. It is concluded that, apart from flooding and other factors, vibrations – simulating the patter of rainfall – provide a very significant hatching stimulus for Aedes eggs.
Relationships of extant lower Brachycera (Diptera): a quantitative synthesis of morphological characters
Authors: Yeates David K.
Published: March 2003

With over 80 000 described species, Brachycera represent one of the most diverse clades of organisms with a Mesozoic origin. Larvae of the majority of early lineages are detritivores or carnivores. However, Brachycera are ecologically innovative and they now employ a diverse range of feeding strategies. Brachyceran relationships have been the subject of numerous qualitative analyses using morphological characters. These analyses are often based on characters from one or a few character systems and general agreement on relationships has been elusive. In order to understand the evolution of basal brachyceran lineages, 101 discrete morphological characters were scored and compiled into a single data set. Terminals were scored at the family level, and the data set includes characters from larvae, pupae and adults, internal and external morphology, and male and female terminalia. The results show that all infraorders of Brachycera are monophyletic, but there is little evidence for relationships between the infraorders. Stratiomyomorpha, Tabanomorpha, and Xylophagomorpha together form the sister group to Muscomorpha. Xylophagomorpha and Tabanomorpha are sister groups. Within Muscomorpha, the paraphyletic Nemestrinoidea form the two most basal lineages. There is weak evidence for the monophyly of Asiloidea, and Hilarimorphidae appear to be more closely related to Eremoneura than other muscomorphs. Apsilocephalidae, Scenopinidae and Therevidae form a clade of Asiloidea. This phylogenetic evidence is consistent with the contemporaneous differentiation of the main brachyceran lineages in the early Jurassic. The first major radiation of Muscomorpha were asiloids and they may have diversified in response to the radiation of angiosperms in the early Cretaceous.
Phylogeny of the Hymenoptera: a reanalysis of the Ronquist et al. (1999) reanalysis, emphasizing wing venation and apocritan relationships
Authors: Sharkey Michael J. , Roy Alain
Published: March 2003

Ronquist et al. (1999) recoded Rasnitsyn’s (1988) analysis to effect an explicit numerical cladistic analysis of his data. Here we examine their analysis and reveal that much of the resolution obtained for apocritan relationships is dependant on reductional wing characters. The wing characters in their matrix are replaced with a revised set of wing characters and reanalysed using strict parsimony. For apocritan taxa the resulting strict consensus tree is considerably less resolved, but perhaps preferable as a more conservative starting point in the continuing investigation of higher level hymenopteran relationships.
Phylogeny of the holometabolous insect orders: molecular evidence
Authors: Whiting Michael F.
Published: March 2003

Phylogenetic relationships among the holometabolous insect orders were reconstructed using 18S ribosomal DNA data drawn from a sample of 182 taxa representing all holometabolous insect orders and multiple outgroups. Parsimony analysis supports the monophyly of all holometabolous insect orders except for Coleoptera and Mecoptera. Mecoptera is paraphyletic with respect to Siphonaptera, which is nested within Mecoptera. Coleoptera is scattered as a paraphyletic assemblage across the tree topology. These data support a monophyletic Halteria (Strepsiptera + Diptera), Amphiesmenoptera (Trichoptera + Lepidoptera), Neuropterida (Neuroptera + (Megaloptera + Raphidioptera)), but Antliophora (Halteria + Mecoptera + Siphonaptera) and Mecopterida (Antliophora + Amphiesmenoptera) are paraphyletic. The limitations of using 18S ribosomal DNA as the sole phylogenetic marker for reconstructing insect ordinal relationships are discussed.
Induction of Oral Tolerance with Micro‐Doses of Ovomucoid Depends on the Length of the Feeding Period
Authors: Kjær T. M. R. , Frøkiær H.
Published: March 2003

Oral administration of antigen induces antigen‐specific immunologic tolerance, which is known to be dose‐dependent. We studied the influence of continuous oral administration of nanogram and microgram doses of antigen on oral tolerance induction. Mice were continuously exposed to varying doses (1 ng−1 mg/day) of ovomucoid (OM) for a minimum of 30 days and a maximum of 100 days. It was possible to induce oral tolerance measured as reduced proliferation and antibody production (immunoglobulin (Ig)G1, IgG2a and total Igs) when mice were fed 1 mg of OM/day for 40 or 50 days. It was not possible to induce oral tolerance with daily doses of antigen of 10 µg or less. Feeding of 100 µg OM/day for 40 and 50 days and 1 mg OM/day for 30 days generated tolerization of Th2‐dependent responses, but retained an intact response of Th1‐dependent antibodies, whereas feeding of 1 mg OM/day for 40 and 50 days resulted in tolerization of both Th1‐ and Th2‐antibody responses. The results presented here suggest that there is a threshold of microgram‐doses below which oral tolerance cannot be induced, and that selective suppression of Th2 responses can be achieved by continuous microdose feeding, while an extension of the feeding dose or feeding period tolerizes both Th1‐ and Th2‐dependent responses.
Skeletal muscle pathology in autosomal dominant Emery‐Dreifuss muscular dystrophy with lamin A/C mutations
Authors: Sewry C. A. , Brown S. C. , Mercuri E. , Bonne G. , Feng L. , Camici G. , Morris G. E. , Muntoni F.
Published: March 2003

We present our observations on the skeletal muscle pathology of nine cases from seven families of autosomal dominant Emery‐Dreifuss muscular dystrophy (ADEDMD) with identified mutations in the lamin A/C gene, aged 2–35 years at the time of biopsy. The severity of pathological change was moderate and the most common features were variation in fibre size (hypertrophy and atrophy), an increase in internal nuclei and smaller diameter fibres with high oxidative enzyme activity. Only one case showed necrosis, which was present in two separate samples taken from the quadriceps and tibialis anterior, at different ages. Immunocytochemistry detected an age‐related reduction of laminin β1 on the muscle fibres in adolescent and adult cases. Antibodies to lamins A and A/C, and emerin did not reveal any detectable differences from controls. Electron microscopy of two out of three cases showed an abnormal distribution of heterochromatin in many fibre nuclei. Our results show that dystrophic changes in skeletal muscle are not a major feature of ADEDMD, and that nuclear abnormalities may be detected with electron microscopy. Immunodetection of reduced laminin β1 may be a useful secondary marker in adults with this disorder, as immunocytochemistry of lamins is not yet of diagnostic use.
Exposure to cold: aversive Pavlovian conditioning in individual Drosophila melanogaster
Authors: Phelan Laura L. , Rodd Zachary A. , Hirsch Helmut V. B. , Rosellini Robert A.
Published: March 2003

Abstract. Temperature changes can be especially threatening for ectotherms, such as Drosophila melanogaster (Diptera: Drosophilidea Meigen, 1830), and in this study we tested whether flies can associate olfactory stimuli with a sudden drop in temperature. Such Pavlovian conditioning would allow them to make appropriate behavioural and/or physiological responses in the future. We found that exposing individual flies to one of two odours in the presence of a sudden drop in temperature resulted in Pavlovian conditioning with flies subsequently avoiding the odour paired with cold. The characteristics of Pavlovian conditioning in flies were comparable to those observed for mammalian species. Specifically, the strength of conditioning increased with increasing intensity of the cold and decreased as the time interval between the olfactory stimulus (CS) and cold (US) was lengthened. Finally, the order in which CS and US were presented affected the strength of conditioning. Learning was observed when the CS preceded US and when the US immediately preceded the CS, but not when the CS preceded the US by 30 s or more. These results provide further evidence for learning in individual flies, and confirm that Pavlovian conditioning is a general mechanism used by organisms to obtain information about their environment.
Amino acids as respiratory substrates in aphids: an analysis of Aphis fabae reared on plants and diets
Authors: Wilkinson T. L. , Minto L. B. , Douglas A. E.
Published: March 2003

Abstract. The fate of radioactively labelled amino acids injected into the haemolymph of the aphid Aphis fabae was investigated. Radioactivity from each of L‐[U‐14C]‐glutamic acid, L‐[U‐14C]‐serine and L‐[U‐14C]‐threonine in the aphid tissues declined exponentially, at rates of 32, 9.3 and 1.0 pmol/aphid/min, respectively. For 14C‐glutamic acid, radioactivity lost from the aphids was recovered quantitatively as carbon dioxide, and radioactivity in aphid saliva and honeydew was undetectable. When expressed on a per unit aphid biomass basis, the rate of respiratory loss of glutamic acid from aphids reared on chemically‐defined diets was more than double that of aphids reared on the host plant, Vicia faba. It is concluded that respiration is a quantitatively important component to the aphid metabolism of glutamic acid and other amino acids.
Comparative dynamics of gestalt odour formation in two ant speciesCamponotus fellahandAphaenogaster senilis(Hymenoptera: Formicidae)
Authors: Lenoir Alain , Hefetz Abraham , Simon Tovit , Soroker Victoria
Published: March 2003

Abstract.Ant colonies experience continuous shifts in worker populations, which may affect odour composition in the nest. A major question regarding the dynamics of gestalt formation is that of the speed at which the scent of a new individual will be incorporated into the gestalt. It is predicted from the gestalt model of colony odour that workers have to exchange recognition cues continuously to maintain themselves within the gestalt and become well integrated within their colony. Using radioactive tracers the rates of transfer were measured between a labelled donor ant and one or 10 recipient ants, as a close approximation to the within‐nest situation. The labelled hydrocarbons were first transferred to a small number of individuals and progressively to all the individuals of the group so that the distribution of hydrocarbon transfer rate approached a normal distribution. Furthermore, inCamponotus fellahDalla Torre, which performs trophallaxis, homogeneity was reached more rapidly than inAphaenogaster senilisMayr, which does not show this behaviour. In the latter species, the gestalt seems to be maintained mainly by allogrooming. These experiments were accompanied by behavioural observations to ascertain the respective importance of trophallaxis and allogrooming in the behavioural time‐budget of the ants. InA. senilis, allogrooming was more frequent than in ants that trophallax, which corroborates the role of allogrooming in the establishment of the gestalt in this species.
Low‐temperature storage and cold hardiness in two populations of the predatory midge Aphidoletes aphidimyza, differing in diapause intensity
Authors: Košťál Vladimír , Havelka Jan , Šimek Petr
Published: March 2003

Abstract. The potential for medium‐time, low‐temperature storage was compared in diapausing larvae of two populations of Aphidoletes aphidimyza, a predatory midge used to control aphids in greenhouses. During 4 months of storage, no statistical decrease of survival rate (c. 75%) was observed in the population Palamos (field collected). However, a significant decrease (below 50%) was recorded in the population Biobest (commercial, selected for the best performance in greenhouses). Measuring physiological parameters related to the rate of diapause development revealed that the larvae of the population Palamos (in contrast to Biobest) showed a significant metabolic suppression even at the relatively high temperature of 17°C, a slower rate of glycogen depletion during storage at 3°C and a longer duration of diapause development (a higher intensity of diapause, collectively). A higher capacity for survival at subzero temperatures (cold hardiness), in either the supercooled or frozen state, was also found in the Palamos population. It is suggested that the higher survival at low‐temperature storage might be linked directly to the higher diapause intensity. It remains unclear, however, whether and how the performance during low‐temperature storage is linked to the capacity for cold hardiness.
Systematics of Otarrha, a new Neotropical subgenus of Chimarra (Trichoptera: Philopotamidae)
Authors: Blahnik Roger J.
Published: March 2003

Abstract. Subgenus Otarrha is established in genus Chimarra to include eighteen described species formerly placed either in subgenus Chimarra or unplaced to subgenus, and thirteen new species. All species are Neotropical, with collective distributions primarily in the Antilles (Greater and Lesser) and northern South America. One species occurs in southeastern Brazil and another species in Costa Rica and Panama. New species are described, recognized species redescribed (except for C. diannae and C. koki), and a key to the identification of males in the subgenus is provided. Additionally, characters supporting monophyly of the subgenus and a phylogeny of its species are proposed. Described species transferred to this subgenus include Chimarra cubanorum Botosaneanu, C. diakis Flint, C. diannae Flint & Sykora, C. dominicana Flint, C. garciai Botosaneanu, C. guapa Botosaneanu, C. jamaicensis Flint, C. koki Botosaneanu, C. machaerophora Flint, C. patosa Ross, C. puertoricensis Flint, C. quadrifurcata Botosaneanu, C. retrorsa Flint, C. rossi Bueno‐Soria, C. sensillata Flint, C. septemlobata Flint, C. septifera Flint and C. spinulifera Flint. Chimarra patosa is designated the type species of the subgenus. New species described in Otarrha include Chimarra amazonia (Peru), C. barinas (Venezuela), C. darlingtoni (Cuba), C. diaphora (Venezuela), C. incipiens (Venezuela), C. odonta (Brazil), C. parene (Peru), C. parilis (Peru), C. particeps (Peru), C. peruana (Peru), C. phthanorossi (Colombia), C. redonda (Dominican Republic) and C. tachuela (Venezuela). Two additional species are described and left incertae sedis to subgenus, Chimarra usitatissima Flint and C. angularis, sp.n. (Venezuela, Guyana).
Characterization of the barrier function in a reconstituted human epidermis cultivated in chemically defined medium
Authors: Garcia N. , Doucet O. , Bayer M. , Fouchard D. , Zastrow L. , Marty J. P.
Published: March 2003

Synopsis

The aim of the study was to characterize and assess the maturation process of the barrier function in a reconstituted human epidermis (REp) cultivated in a chemically defined medium. For this purpose histo‐morphological analysis, percutaneous absorption studies and non‐invasive measurements were performed. In order to understand the time course of the barrier development, REp cultivated from the same pool of normal human keratinocytes were harvested and measured after several increasing periods of exposure at the air–liquid interface. From these results we concluded that a maturation period of at least 16 days at the air–liquid interface was required for an optimal barrier function development of REp. At this time point, the permeability of the skin cultures for caffeine (CAF) was 20–25‐fold higher than that of normal human skin (NHS) biopsies. Non‐invasive measurements of skin water content, transepidermal water loss (TEWL) and pH were achieved after the same period of time. Results showed that the stratum corneum (SC) of REp was slightly more hydrated than that of ex vivo and in vivo, human skin. TEWL was slightly higher through REp than through NHS, and the pH of the REp models was very close to that of in vivo, normal human skin. In the latter part, assuming that this type of model could be routinely used, we quantified over a 1‐year period the barrier function variability of this skin culture model between batches. The satisfactory results obtained with a 20% coefficient of variation indicated that this REp model has a consistent and reproducible barrier function. This leads us to suggest that the skin model might be considered an alternative membrane to normal human skin for permeation screening tests.
Development of an in vitro efficacy test for self‐tanning formulations
Authors: Jermann R. , Toumiat M. , Imfeld D.
Published: March 2003

Synopsis

In the last few years, the desire to acquire a tan without sunbathing has grown. In response, many cosmetic companies have produced self‐tanning preparations. However, to optimize these formulations, a suitable model to assess the colour induced on the skin remains to be developed. We have developed an in vitro method using a synthetic skin in order to study the efficacy of self‐tanning formulations. The in vitro test was then used to study the influence of cosmetic ingredients upon the colour induced by erythrulose‐ or dihydroxyacetone‐containing formulations. Finally, an in vivo study allowed us to relate the results obtained in vitro with those found on human skin. The results show that this in vitro test system is a reliable tool to predict the efficacy of self‐tanning products.
Animal models of autoimmune liver disease
Authors: Peters Marion G
Published: March 2003

Autoimmune liver diseases in humans are characterized by chronic active hepatitis with serum autoantibodies, hypergammaglobulinemia and liver pathology showing necroinflammatory disease and fibrosis. There are an increasing number of autoantigens believed to be associated with various autoimmune liver diseases. This review will briefly outline human autoimmune hepatitis and the immunology of the liver. Various murine models of liver inflammation will be discussed, including transgenic and non‐transgenic models, with emphasis on how these models aid in our knowledge of the mechanisms of disease development and chronicity. There are limitations with all of the models, including a preponderance of T‐cell‐focused responses. Murine models do not easily develop fibrosis, a hallmark of autoimmune hepatitis in humans. Different experimental models may not reach the same conclusions with differences between immune responses. However, this multiplicity of responses does not necessarily imply that these models are inappropriate for the study of liver immunology and autoimmune liver diseases, as different autoantigens may induce different liver responses. Knowledge of how the liver differs from other immune organs is essential to further our understanding of liver‐specific autoimmunity. The plethora of antigens implicated in autoimmune hepatitis in humans predicts that multiple mechanisms may play a role in precipitating disease in the susceptible individual.
Improving vaccines against tuberculosis
Authors: Britton Warwick J , Palendira Umaimainthan
Published: March 2003

Tuberculosis remains a major cause of mortality and physical and economic deprivation worldwide. There have been significant recent advances in our understanding of the Mycobacterium tuberculosis genome, mycobacterial genetics and the host determinants of protective immunity. Nevertheless, the challenge is to harness this information to develop a more effective vaccine than BCG, the attenuated strain of Mycobacterium bovis derived by Calmette and Guérin nearly 90 years ago. Some of the limitations of BCG include the waning of the protective immunity with time, reduced effectiveness against pulmonary tuberculosis compared to disseminated disease, and the problems of a live vaccine in immuno‐compromised subjects. Two broad approaches to vaccine development are being pursued. New live vaccines include either attenuated strains of Mycobacterium tuberculosis produced by random mutagenesis or targeted deletion of putative virulence factors, or by genetic manipulation of BCG to express new antigens or cytokines. The second approach utilizes non‐viable subunit vaccines to deliver immunodominant mycobacterial antigens. Both protein and DNA vaccines induce partial protection against experimental tuberculosis infection in mice, however, their efficacy has generally been equivalent to or less than that of BCG. The comparative effects of cytokine adjuvants and vaccines targeting antigen presenting cells on enhancing protection will be discussed. Coimmunization with plasmid interleukin‐12 and a DNA vaccine expressing Antigen 85B, a major secreted protein, was as protective as BCG. The combination of priming with DNA‐85B and boosting with BCG was superior to BCG alone. Therefore it is possible to achieve a greater level of protection against tuberculosis than with BCG, and this highlights the potential for new tuberculosis vaccines in humans.
Stability and activity of specific antibodies against Streptococcus mutans and Streptococcus sobrinus in bovine milk fermented with Lactobacillus rhamnosus strain GG or treated at ultra‐high temperature
Authors: Wei H. , Loimaranta V. , Tenovuo J. , Rokka S. , Syväoja E‐L. , Korhonen H. , Joutsjoki V. , Marnila P.
Published: March 2003

Passive local immunization against dental caries is a promising approach to its prevention, as clinical evidence of active oral or nasal immunization is still limited and controversial. By means of systemic immunization of pregnant cows with a multivalent vaccine, high titres of IgG antibodies against human cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus, were produced in bovine colostrum. The purified immune product (IP) of this preparation has a number of anticariogenic properties, such as inhibition of streptococcal adherence to saliva‐coated hydroxyapatite and inhibition of glucosyltransferase enzymes. This study investigated whether IP antibodies remained active and functional when added to ultra‐high temperature (UHT)‐treated milk or to Lactobacillus rhamnosus GG (LGG)‐fermented milk stored for an extended time. LGG was chosen because of its widely known health benefits in humans and animals. A commercial UHT toddler's milk was supplemented with IP and stored for 2 months at 5, 21 and 30°C. The antistreptococcal titres in UHT milk did not decline at any temperature during storage, and UHT‐IP inhibited the adherence of S. mutans for up to 2 months. This was not the case with UHT toddler's milk without IgG antibodies. Milk was fermented with live LGG cells in the presence or absence of 5% IP. The antistrept?ococcal titres declined to about 30% of the original titres after storage. Fresh milk alone slightly enhanced streptococcal adhesion but fresh milk with IP inhibited the adherence of S. mutans by over 50%. LGG‐positive fermented milk without antibodies also inhibited (P < 0.05) the adhesion by about 40%. In both LGG‐fermented and UHT immune milk, the activity of antibodies against cariogenic streptococci was maintained during the expected shelf‐life of these products. From the anticariogenic point of view it may be beneficial to add bovine‐specific antibodies against mutans streptococci to probiotic LGG‐containing milk products.
The effect of tissue molecules on bacterial invasion of dentine
Authors: Love R. M.
Published: March 2003

Bacterial invasion of dentinal tubules is a critical step in the pathogenesis of dental caries and pulp and periapical disease. The purpose of this study was to determine the effect some molecules commonly found in saliva and dentinal tubule fluid may have on the bacterial invasion of dentine. The results showed that invasion of Streptococcus gordonii or Enterococcus faecalis cells was inhibited when the bacterial cells were in solution with mucin, immunoglobulin G (IgG) and serum, and this was related to bacterial cell aggregation, as a result of interaction with agglutinins, and/or inhibition of collagen binding. When dentine was soaked in growth media containing fibrinogen, IgG, albumin or serum prior to inoculation, bacterial invasion was inhibited. It is suggested that this may be due to reduced dentine permeability as a consequence of the deposition of the compounds within dentinal tubules.
Otomycosis in Nigeria: treatment with mercurochrome
Authors: Mgbor Nnennia , Gugnani H. C.
Published: March 2003

Summary.  Seventy‐two mycologically proven cases of otomycosis (38 males, 34 females) aged 8–80 years were investigated. Aspergillus niger was the commonest aetiological agent (43.1%) followed by Candida spp. (22.2%), A. flavus (19.4%) and A. fumigatus (15.3%). Three topical drugs, namely mercurochrome, clotrimazole and locacorten‐vioform, were evaluated for otomycosis therapy in separate groups of 24 patients each. Mercurochrome was found to be the most efficacious in terms of healing, relief from symptoms of the disease and production of negative fungal cultures. Mercurochrome is recommended as a safe and economical drug for the topical treatment of otomycosis in developing countries like Nigeria.
From fact to recommendation: explicit value premises make the conclusion more convincing
Authors: Nilstun T. , Sjökvist P.
Published: March 2003

Abstract. Nilstun T, Sjökvist P (Lund University, Lund; and Huddinge University Hospital, Huddinge; Sweden). From fact to recommendation: explicit value premises make the conclusion more convincing (Review). J Intern Med 2001; 249: 121–125.

In this article we describe one way to use value premises, i.e. conceptions of what is right or wrong, good or bad, just or unjust. They may, in combination with the results from surveys on attitudes, be used to defend normative conclusions, for example changes in professional guidelines. Several ethical principles may be relevant when discussing an end‐of‐life decision. We use the preferences of those involved in or affected by that decision (the principle of autonomy) and the obligation to maximize benefits and minimize harm (the principle of beneficence) as value premises. To illustrate the ethical, empirical and logical issues relevant to assess normative conclusions, we present a Swedish survey of the attitudes of health care workers and the general public. In this survey, the physicians stated that they do not want the family to be the sole decision‐maker, whilst the public did not want the physician to be the sole decision‐maker. As a third option we propose joint decision‐making regarding end‐of‐life decisions. This normative conclusion may be rationally discussed, not only by questioning scientific aspects of the survey, but also by critically assessing value premises (autonomy and beneficence) and the logic of the argument.