bluuebunny/crossref_metadata_2025 huggingface dataset:
Conjunctival macrophage‐mediated influence of the local and systemic immune response after corneal herpes simplex virus‐1 infection
Authors: Bauer Dirk , Schmitz Andreas , Van Rooijen Nico , Steuhl Klaus‐Peter , Heiligenhaus Arnd
Published: March 2003

Recently it has been shown that selective subconjunctival macrophage depletion reduced the incidence and severity of stromal herpes simplex virus (HSV) keratitis in mice. In this study, we examined the effect of conjunctival macrophage depletion on the corneal and systemic T‐cell‐mediated immune response. BALB/c mice were treated with subconjunctival injections of dichloromethylene diphosphonate (Cl2MDP)‐liposomes (Cl2MDP‐LIP) or phosphate‐buffered saline (PBS) 7 and 2 days before corneal infection with 105 plaque‐forming units (PFU) of HSV‐1 (KOS strain). Interferon (IFN)‐γ, interleukin (IL)‐2, and IL‐4 production in the cornea was analysed by enzyme‐linked immunosorbent assay (ELISA), and cytokine mRNA levels (IFN‐γ, IL‐4) were measured by semiquantitative reverse transcription–polymerase chain reaction (RT‐PCR). Cell culture supernatants from submandibular lymph nodes were analysed by ELISA for expression of IFN‐γ, IL‐2, and IL‐4 and by bioassay for IL‐6. The HSV‐1‐specific proliferative response of lymphocytes from regional lymph nodes and the delayed‐type hypersensitivity (DTH) response were tested after corneal infection. Virus‐neutralizing antibody titres and HSV‐1‐specific immunoglobulin G (IgG)2a/IgG1‐ratios were measured. Cytokine mRNA expression (IFN‐γ, IL‐4) and secretion (IFN‐γ, IL‐2, IL‐4) in the corneas were decreased after HSV‐1 corneal infection in the macrophage‐depleted mice. The secretion of IFN‐γ and IL‐2 was decreased in the regional lymph nodes from Cl2MDP‐LIP‐treated animals (P<0·05). Furthermore, Cl2MDP‐LIP‐treated mice had decreased HSV‐1 specific proliferative responses (P<0·05) and DTH response after corneal HSV‐1 infection (P<0·05). The virus‐neutralizing serum‐antibody levels (P<0·05) increased while the HSV‐1 specific IgG2a/IgG1‐ratio was unaffected after macrophage depletion. Macrophage depletion did not induce a shift between the T helper 1 (Th1) and Th2 response in this HSK model. The data suggest that conjunctival macrophage functions are enhancing the T‐cell‐mediated immune response after corneal infection. This effect is at least in part responsible for the impaired course of herpetic keratitis after macrophage depletion.
Reactivation of latent tuberculosis by an inhibitor of inducible nitric oxide synthase in an aerosol murine model
Authors: Botha Tania , Ryffel Bernhard
Published: March 2003

Exposure to Mycobacterium tuberculosis results in clinical tuberculosis only in a small percentage of healthy individuals. In most instances the bacilli are controlled by the immune system and survive in a latent state within granuloma. Immunosuppression, however, may result in reactivation of infection, resulting in clinical disease. Using a low‐dose aerosol infection (30 colony‐forming units) in mice, we describe a short‐duration model for studying spontaneous and drug‐induced reactivation of anti‐tuberculous drug‐treated, latent tuberculosis infection. Although a 4‐week treatment with rifampicin and isoniazid reduced the number of bacilli to undetectable levels, the infection spontaneously reactivated following therapy. By contrast, an 8‐week treatment period induced a state of latent infection, requiring immunosuppression to reactivate infection. Finally, a 12‐week treatment period eliminated the bacilli completely and aminoguanidine did not induce reactivation of infection. In view of the fact that therapy in the selected protocol reduces the mycobacterial load to undetectable levels, the data suggest that an 8‐week treatment period is necessary and sufficient to mount protective immunity in mice.
Tumour necrosis factor‐α (TNF‐α) transgene‐expressing dendritic cells (DCs) undergo augmented cellular maturation and induce more robust T‐cell activation and anti‐tumour immunity than DCs generated in recombinant TNF‐α
Authors: Zhang Weidong , Chen Zhuang , Li Fang , Kamencic Huse , Juurlink Bernie , Gordon John R. , Xiang Jim
Published: March 2003

Tumour antigen presentation by dendritic cells (DCs) to T cells in lymphoid organs is crucial for induction of anti‐tumour immune responses. It has been previously reported that tumour necrosis factor‐α (TNF‐α) is required for DC activation and subsequent induction of optimal immune responses, and thus DCs for anti‐tumour vaccination are often generated by culture in exogenous TNF‐α. In the present study, we investigated the effect on anti‐tumour immunity of vaccination with Mut1 tumour peptide‐pulsed DCs engineered to express a TNF‐α transgene. Our data shows that transfection of DCs with recombinant adenovirus AdV‐TNF‐α resulted in greater maturation of the DCs than occurred with control DCs cultured in exogenous TNF‐α, as determined by up‐regulated expression of pro‐inflammatory cytokines (e.g. interleukins 1β and 18), chemokines [e.g. interferon‐γ‐inducible protein‐10 and macrophage inflammatory protein‐1β (MIP‐1β)], the CC chemokine receptor CCR7, and immunologically important cell surface molecules (CD40, CD86 and intercellular adhesion molecule‐1). These transgenic DCs stimulated stronger allogeneic T‐cell responses in vitro and T‐cell activation in vivo; displayed 2·4‐fold enhanced chemotactic responses to the MIP‐3βin vitro (P<0·05); and, perhaps most importantly, trafficked into the draining lymph nodes dramatically (seven‐fold, P<0·01) more efficiently than the control DCs. Our data also demonstrate that vaccination of mice with Mut1 peptide‐pulsed, AdV‐TNF‐α‐transfected DCs stimulated more efficient in vitro Mut1‐specific CD8+ cytotoxic T‐cell responses and solid tumour immunity in vivo, when compared to the in vitro TNF‐α‐cultivated DCs. Thus, DCs engineered to secrete TNF‐α may offer a new strategy in DC cancer vaccines.
Successfully completing case study research: combining rigour, relevance and pragmatism
Authors: Darke Peta , Shanks Graeme , Broadbent Marianne
Published: March 2003

The organizational and social issues associated with the development, implementation and use of computer‐based information systems have increasingly attracted the attention of information systems researchers. Interest in qualitative research methods such as action research, case study research and ethnography, which focus on understanding social phenomena in their natural setting, has consequently grown. Case study research is the most widely used qualitative research method in information systems research, and is well suited to understanding the interactions between information technology‐related innovations and organizational contexts. Although case study research is useful as a means of studying information systems development and use in the field, there can be practical difficulties associated with attempting to undertake case studies as a rigorous and effective method of research. This paper addresses a number of these difficulties and offers some practical guidelines for successfully completing case study research. The paper focuses on the pragmatics of conducting case study research, and draws from the discussion at a panel session conducted by the authors at the 8th Australasian Conference on Information Systems, September 1997 (ACIS 97), from the authors' practical experiences, and from the case study research literature.
Towards the construction of workflow‐suitable conceptual modelling techniques
Authors: Barros A. P. , Ter Hofstede A. H. M.
Published: March 2003

Despite their high‐level and graphical nature, workflow specifications require a significant amount of implementation detail — for example application programming interface, database access and programming mechanisms for information flow — for a more comprehensive validation than is currently possible. This is currently recognized as a deficiency in workflow conceptualization. Although conceptual modelling techniques are available which are expressive, comprehensive and precise enough, we believe, their concepts and features are not specialized enough for workflow domains. In this paper, we offer a comparative insight into techniques which characterize different aspects and approaches of workflow specifications. These are: structured process modelling, object‐oriented modelling, behavioural process modelling and business‐oriented modelling. In particular, we determine gaps for workflows capturing operational business transaction processing, for example those of insurance claims, bank loans and government‐related registration. For technique construction, we describe five workflow suitability principles.
The effect of transaction costs on the decision to replace ‘off‐the‐shelf’ software: the role of software diffusion and infusion
Authors: Castner Grant , Ferguson Colin
Published: March 2003

This study examines the extent to which software diffusion and infusion affect the decision to replace ‘off‐the‐shelf’ software, using the example of spreadsheet software. Transaction cost economics motivates the propositions that higher levels of software diffusion and higher levels of software infusion act as disincentives on the firm’s decision to upgrade or change off‐the‐shelf software. Our focus on software diffusion and infusion extends previous research that only examined hardware infusion and diffusion. Results from the study, using a survey, newsgroups and interviews, generally support the propositions and show that the more software is diffused and infused into a firm, the less likely it is to be changed or upgraded. More specifically, the results also show that, while software infusion acts directly to reduce the likelihood of software replacement, software diffusion only affects it indirectly through its effect on infusion.
Reflections on information systems practice, education and research: 10 years of the Information Systems Journal
Authors: Avison David , Fitzgerald Guy , Powell Philip
Published: March 2003

This paper celebrates the 10‐year anniversary of the Information Systems Journal (ISJ) and the Editors reflect on the papers that have been published over that period and the changes that have occurred in the discipline of information systems. In the opening paper of ISJ, we suggested that the ‘launch of a new journal in information systems prompts thought and debate concerning the state of the subject area and some contemplation of its past and future’. We discussed three areas of this ‘not‐yet‐established discipline’: practice, education and research. In this follow‐up paper, we forgo our convention of ISJ editors not publishing in the Journal. We examine the issues raised in the first paper and consider what has happened in the intervening years as charted in the ISJ. The overview is necessarily selective, probably Anglocentric (with, perhaps, a slight Francophile tinge), sometimes downright opinionated, as well as over‐estimating, perhaps, the contribution of one particular IS journal.
The issue of gender within computing: reflections from the UK and Scandinavia
Authors: Robertson Maxine , Newell Sue , Swan Jacky , Mathiassen Lars , Bjerknes Gro
Published: March 2003

Abstract. Thispaper explores some of the reasons that may underlie the gender segregation and declining levels of female participation within the field of computing in Europe during the 1990s in both the professional (industrial) and academic spheres. The interrelationships between three areas – communicative processes, social networks and legitimizing claims to knowledge overlaid by gendered‐power relations – are used to analyse and explain the existing situation. The paper draws upon statistical data to explore the extent of gender segregation and then focuses on the authors' own experiences within the UK and Scandinavia in order to explore some of the underlying causes. While direct discrimination does still occur, the paper suggests that indirect, deep‐rooted discrimination is the major reason for the situation that currently exists. Drawing upon our own experiences in academia and business and acknowledging the importance of the institutional context, the paper offers a number of recommendations as to how the current situation may be improved. We suggest first that consideration is given to the pedagogical design and marketing of computing courses so that individuals are initially attracted to computing from far more diverse backgrounds, approaches and interests than at present. Second, we suggest that those with influence in the field reflect upon the constitution and behaviours of the informal networks in which they are involved and seek to include female researchers more actively here. Finally we suggest that consideration is given in more general terms to how the field may become more gender neutral and, thus, more inclusive in the future. Masculine discourses and ‘hard’ skills have dominated within computing for too long and contribute significantly to the declining participation of women within computing.
A sodium channel point mutation is associated with resistance to DDT and pyrethroid insecticides in the peach‐potato aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae)
Authors: Martinez‐Torres D. , Foster S. P. , Field L. M. , Devonshire A. L. , Williamson M. S.
Published: March 2003

The voltage‐gated sodium channel is the primary target site of DDT and pyrethroid insecticides, and point mutations in the domain II region of the channel protein have been implicated in the knockdown resistant (kdr ) phenotype of several insect species. Here, we report that one of these mutations, a leucine‐to‐phenylalanine replacement in transmembrane segment IIS6, is also found in certain insecticide‐resistant clones of the peach‐potato aphid, Myzus persicae. The mutation was present in four clones with amplified E4 esterase genes, but was absent from both susceptible clones and those with amplified FE4 genes. The inferred presence of kdr‐type resistance in the four E4 clones was subsequently confirmed by bioassays that showed this to be the primary mechanism of resistance to deltamethrin and DDT, although the esterase‐based mechanism also contributes to the overall level of deltamethrin resistance. The kdr mutation on its own conferred 35‐fold resistance to deltamethrin and this was enhanced up to 540‐fold when it was present in a high (E4) esterase background. The esterase (FE4) mechanism was far less effective without the kdr mutation, conferring just 3–4‐fold resistance to deltamethrin. These findings, and the linkage disequilibrium of the kdr mutation within clones overproducing the E4 esterase, have important implications for the evolution of resistance in this insect and for the use of pyrethroid sprays in the management of M. persicae populations in the field.
Green fluorescent protein as a genetic marker in transgenic Aedes aegypti
Authors: Pinkerton A. C. , Michel K. , O'Brochta D. A. , Atkinson P. W.
Published: March 2003

We report here the use of the enhanced green fluorescent protein (EGFP) from the jellyfish, Aequorea victoria, as a genetic marker for the genetic transformation of mosquitoes. The EGFP gene, under the control of the actin5C promoter of Drosophila melanogaster was inserted into the Hermes transposable element. Preblastoderm embryos of a wild‐type strain of the yellow fever mosquito, Aedes aegypti, were microinjected with this plasmid, together with a helper plasmid containing the Hermes transposase placed under the control of the D. melanogaster hsp70 promoter. Somatic EGFP expression was observed during early instars in approximately one‐half of all G0 individuals. Two G1 individuals arising from a G0 female displayed high levels of EGFP gene expression during all stages of development. EGFP was transmitted in a Mendelian fashion to the G2 and G3 generations and molecular analysis confirmed the presence of the Hermes[actin5C:EGFP] gene in these insects. These results clearly demonstrate that EGFP can be used as an effective genetic marker in wild‐type Ae. aegypti and most likely in other mosquito species as well.
Long PCR improvesWolbachiaDNA amplification:wspsequences found in 76% of sixty‐three arthropod species
Authors: Jeyaprakash A. , Hoy M. A.
Published: March 2003

Bacteria belonging to the genusWolbachiaare associated with a variety of reproductive anomalies in arthropods. Allele‐specific polymerase chain reaction (= Standard PCR) routinely has been used to amplifyWolbachiaDNA from arthropods. While testing the two‐spotted spider miteTetranychus urticaeand other arthropods known to be infected withWolbachia, Standard PCR frequently produced false negatives, perhaps because the DNA from the arthropod host interfered with amplification byTaqDNA polymerase. Long PCR, which uses two enzymes (TaqandPwo), consistently amplifiedWolbachiaDNA and a sensitivity analysis indicated that Long PCR was approximately six orders of magnitude more sensitive than Standard PCR in amplifying plasmid DNA spiked into insect genomic DNA. A survey indicated that 76% of sixty‐two arthropod species and two subspecies in thirteen orders tested positive for theWolbachia wspsequence by Long PCR, which is considerably higher than the rate of 16.9% obtained previously for theftsZsequence using Standard PCR (Werren, J.H., Windsor, D. and Gao, L. (1995a)Proc R Soc Lond B262: 197–204). A subsample of Long PCR products from fourteen arthropod species and two subspecies were sequenced, both directly and after cloning. Two A‐ and eleven B‐Wolbachiastrains were detected and theirwspsequences displayed a maximum of 23.7% sequence divergence at this locus. Two new groups (named Fus and Ten) were identified in addition to nineteen reported earlier (Zhou, W., Rousset, F. and O’Neill, S.L. (1998)Proc R Soc Lond B265: 1–7;van Meer, M.M.M., Witteveldt, J. and Stouthamer, R. (1999)Insect Mol Biol8: 399–408), because they displayed more than 2.5% sequence divergence from otherWolbachia wspsequences. PCR products from seventeen of twenty‐nine (59%) arthropod species analysed could not be sequenced directly due to apparent infection by multipleWolbachiastrains. Thewspsequences cloned from two such species (Plutella xylostellaandTrichoplusia ni) indicated both A‐ and B‐Wolbachiawere present in a single individual. Hence, superinfection also may be more widespread than the 1.2% incidence previously estimated.
Genetic mapping of two loci affecting DDT resistance in the malaria vector Anopheles gambiae
Authors: Ranson H. , Jensen B. , Wang X. , Prapanthadara L. , Hemingway J. , Collins F. H.
Published: March 2003

Resistance to the insecticide DDT in the mosquito vectors of malaria has severely hampered efforts to control this disease and has contributed to the increase in prevalence of malaria cases seen in recent years. Over 90% of the 300–500 million annual cases of malaria occur in Africa, where the major vector is Anopheles gambiae. DDT resistance in the ZAN/U strain of An. gambiae is associated with an increased metabolism of the insecticide, catalysed by members of the glutathione S‐transferase (GST) enzyme family, but the molecular mechanism underlying this metabolic resistance is not known. Genetic crosses show that resistance is autosomal and semidominant. We have used microsatellite markers to identify two quantitative trait loci (QTL), which together explain over 50% of the variance in susceptibility to DDT in the ZAN/U strain of An. gambiae. The first locus, rtd1, is on chromosome 3 between markers H341 and H88 and has a recessive effect with respect to susceptibility. The second locus, rtd2 is on chromosome 2L, close to marker H325 and has an additive genetic effect. The markers flanking these two QTL have been physically mapped to An. gambiae polytene chromosomes. They do not coincide with any of the GST genes that have been cloned and mapped in this species. Characterization of these QTL will lead to a clearer understanding of the mechanisms of metabolic resistance to DDT.
Glucosamine:fructose‐6‐phosphate aminotransferase: gene characterization, chitin biosynthesis and peritrophic matrix formation in Aedes aegypti
Authors: Kato N. , Dasgupta R. , Smartt C. T. , Christensen B. M.
Published: March 2003

Glucosamine:fructose‐6‐phosphate aminotransferase (GFAT) catalyses the formation of glucosamine 6‐phosphate and is the first and rate‐limiting enzyme of the hexosamine biosynthetic pathway. The final product of the hexosamine pathway, UDP‐N‐acetyl glucosamine, is an active precursor of numerous macromolecules containing amino sugars, including chitin in fungi and arthropods. Chitin is one of the essential components of insect cuticle and peritrophic matrix. The peritrophic matrix is produced in the midgut of mosquitoes in response to bloodfeeding, and may affect vector competence by serving as a physical barrier to pathogens. It is hypothesized that GFAT plays a regulatory role in biosynthesis of chitin and peritrophic matrix formation in insects. We cloned and sequenced the GFAT gene (AeGfat‐1) and its 5′ regulatory region from Aedes aegypti. There is no intron in AeGfat‐1 and there are two potential transcription start sites. AeGfat‐1 cDNA is 3.4 kb in length and its putative translation product is 75.4 kDa. The amino acid sequence of GFAT is highly conserved in lower and higher eukaryotes, as well as in bacteria. AeGfat‐1 message is constitutively expressed but is gradually up‐regulated in the midgut after bloodfeeding. The putative regulatory region of the gene contains the ecdysone response element, E74, and Broad complex motifs, similar to what is found in the glutamine synthetase gene in Ae. aegypti. Results suggest that Ae. aegypti GFAT‐1 may have a regulatory role in chitin biosynthesis and peritrophic matrix formation, and probably is under the regulation of ecdysteroids.
Ribosomal ITS2 sequence data for Anopheles maculipennis and An. messeae in northern Greece, with a critical assessment of previously published sequences
Authors: Linton Y.‐M. , Samanidou‐Voyadjoglou A. , Harbach R. E.
Published: March 2003

DNA sequences were generated for eight specimens of the Anopheles maculipennis complex from Florina in NW Greece, and identified to species on the basis of comparison with ITS2 sequences for members of the complex already in GenBank. The sequences revealed the presence of An. maculipennis and An. messeae in Florina. Problems with sequence reliability and accessibility of sequences generated in earlier studies of Palaearctic members of the complex are discussed.
Effect of calcium hydroxide as an intracanal dressing on apical leakage
Authors: Çalişkan  , Türkün  , Türkün
Published: March 2003

In this in vitro study, we investigated the effects of the use of two different calcium hydroxide (Ca(OH)2) preparations as an intracanal dressing on the sealing ability of two different sealers were investigated. Eighty‐eight freshly extracted, single‐rooted maxillary anterior teeth were used. After the root canals were hand‐instrumented, they were divided into six groups of 10 each. The root canals were dressed with Ca(OH)2 paste, either mixed with sterile water (in groups 1 and 2) or with glycerine (in groups 3 and 4). The dressed root canals were incubated in 100% humidity at 37°C for 7 days. In groups 5 and 6, the root canals were not dressed. After the root canal dressings were removed by irrigation with 5.25% NaOCl and reaming with a K‐type file, all canals of the experimental groups were obturated with sealer and gutta‐percha using a cold lateral condensation technique. Calciobiotric Root Canal Sealer, (CRCS), (in groups 1, 3 and 5) and Diaket (in groups 2,4 and 6) were used as sealers. All specimens were placed in India ink for 7 days, and the amount of apical leakage was scored. Eight further prepared specimens were dressed with Ca(OH)2 plus water or Ca(OH)2 plus glycerine and examined with scanning electron microscopy (SEM) following the removal of dressings. There was a statistical difference in the leakage patterns amongst the 6 experimental groups (P < 0.05). Specimens in group 2 exhibited less leakage than the other experimental groups, except group 4 (P < 0.05). There were no other significant interactions. SEM examination revealed that Ca(OH)2 crystals were present on the surface of smear layer in both groups where Ca(OH)2 paste had been placed, but they did not penetrate into the dentinal tubules.
Management of apical inflammatory root resorption: report of a case
Authors: Cotti  , Lusso  , Dettori
Published: March 2003

This article describes the diagnosis and treatment of a case of extensive apical external root resorption in the presence of a large periradicular lesion. The diagnosis was made in retrospect because the result of the resorption mimicked an immature root. The treatment consisted of the use of calcium hydroxide to induce apexification. Healing was obtained after 24 months.
A comparative study of the removal of smear layer by three endodontic irrigants and two types of laser
Authors: Takeda F. H. , Harashima T. , Kimura Y. , Matsumoto K.
Published: March 2003

Aim The effects of three endodontic irrigants and two types of laser on a smear layer created by hand instrumentation were evaluated in vitro in the middle and apical thirds of root canals.

Methodology Sixty human mature extracted mandibular premolar teeth with a single root canal and a closed apex were distributed randomly into five groups of 12 teeth each. Whilst cleaning and shaping up to a size 60 master apical file with a step‐back technique, the root canals were irrigated with 3 mL of 5.25% NaOCL and 3% H2O2, alternately, between each file size. Group 1 (G1) were control specimens that were irrigated with a final flush of 17% EDTA. The teeth in group 2 (G2) were irrigated with a final flush of 6% phosphoric acid, and group 3 (G3) with 6% citric acid. In the specimens of group 4 (G4) the root canals were irradiated with a carbon dioxide (CO2) laser, and specimens of group 5 (G5) were irradiated using an Er:YAG laser. The teeth were split longitudinally and prepared for examination by scanning electron microscopy.

Results Control specimens (G1) showed clean root‐canal walls with open dentinal tubules in the middle one‐third, but in some specimens thick smear layer was observed in the apical one‐third.

Specimens irrigated with a final flush of 6% phosphoric acid (G2) or 6% citric acid (G3) were cleaner than with 17% EDTA, showing very clean root canal surfaces in the middle one‐third but in the apical one‐third the smear layer was not completely removed, especially at the openings of the dentinal tubules. The specimens irradiated with the CO2 laser (G4) showed clean root‐canal walls with the smear layer absent, charred, melted, recrystallized and glazed in both middle and apical thirds. The root‐canal walls of the specimens irradiated with the Er:YAG laser (G5) revealed an absent smear layer with open dentinal tubules in the middle and apical thirds. Statistical analysis showed no significant difference in the cleanliness of root‐canal wall between G1 and G2, and G1 and G3. However, there were statistically significant differences (P > 0.01) between G1 and G4, and G1 and G5 in the cleanliness of the middle and apical one‐thirds of the root canals.

Conclusions Irrigation with 17% EDTA, 6% phosphoric acid and 6% citric acid did not remove all the smear layer from the root‐canal system. In addition, these acidic solutions demineralized the interbular dentine around tabular openings, which became enlarged. The CO2 laser was useful in removing and melting the smear layer on the instrumented root‐canal walls and the Er:YAG laser was the most effective in removing the smear layer from the root‐canal wall.
Laser light transmission in teeth: a study of the patterns in different species
Authors: Odor T. M. , Chandler N. P. , Watson T. F. , Ford T. R. Pitt , McDonald F.
Published: March 2003

Aim The aim of this study was to investigate the pattern of light transmission through teeth of different species and to examine laser light propagation within enamel from various animal sources.

Methodology Sectioned teeth from five species – pig, horse, sheep, cat and rat – were evaluated. Samples were illuminated individually by a helium–neon laser light from the buccal surface using a probe 0.5 mm in diameter placed at varying angles between 60 and 1208C. The pattern of light transmission was observed macroscopically. Further evaluation of laserlight transmission in enamel was achieved using confocal microscopy.

Results In each species, light was transmitted through the tooth to the pulp, but in the cat and the rat, light was also transmitted to the far side of the tooth. Despite the different patterns of enamel in the species, light was transmitted through enamel to dentine.

Conclusion Light from a laser Doppler probe appeared to reach the dental pulp in all the species; however, in the mammals with smaller teeth, light may also have been able to reach the periodontium and thus the reflected signal may not be entirely of pulpal origin.
The removal of the smear layer using the Quantec system. A study using the scanning electron microscope
Authors: Bertrand M. ‐F. , Pizzardini P. , Muller M. , Médioni E. , Rocca J. ‐P.
Published: March 2003

Aim The aim of this study was to determine the ability of the Quantec Series 2000 rotary nickel–titanium endodontic system to remove dentinal debris and smear layer produced during canal preparation.

Methodology A first group (control) of 12 curved root canals was prepared using conventional manual instruments and the step‐back technique. A second group of 12 curved root canals was instrumented using the complete Quantec sequence according to the manufacturer’s instructions. In both groups, irrigation was performed using a 3% NaOCl solution. The canal walls were observed under a scanning electron microscope and the coronal, middle and apical thirds of each canal photographed at a magnification of 500.The views were divided into 10 subareas by overlaying a grid, and the absence or presence of a smear layer was rated and scored on three appearances using the scale described by
Ciucchi et al. (1989) .

Results The scores were higher (i.e. less debris was present) in the middle third (P 0.0001) and in the apical third (P 0.0001) of canals prepared with the Quantec system when compared with those prepared with K‐files. Nevertheless, in canals prepared with Quantec instruments, the scores were significantly higher in the coronal third compared with the apical third (P 0.005).

Conclusions The Quantec rotary system produced cleaner canal walls than conventional manual instrumentation, particularly in the middle and apical thirds. This finding may imply that stresses applied to the cutting regions of Quantec instruments by accumulation and compression of the smear layer are minimized.
Calcium hydroxide pastes: classification and clinical indications
Authors: Fava L. R. G. , Saunders W. P.
Published: March 2003

Review article Calcium hydroxide has been used in endodontology for many years. The aim of this paper is to review the various formulations of calcium hydroxide that have been described, with specific reference to the vehicle used to carry the compound. The requirements for a vehicle are described, and ex vivo and in vivo studiesreviewed. Vehicles can be classified into aqueous, viscous and oily, the clinical properties of calcium hydroxide changing depending on the vehicle. The review also describes the use of various active components that have been added to calcium hydroxide, including antimicrobial and anti‐inflammatory agents. This review will help clinicians to make informed judgements about which formulations of calcium hydroxide should be used for specific endodontic procedures.
In vitro susceptibility of Candida albicans to four disinfectants and their combinations
Authors: Waltimo T. M. T. , Ørstavik D. , Sirén E. K. , Haapasalo M. P. P.
Published: March 2003

Waltimo TMT, Ørstavik D, Sirén EK, Haapasalo MPP. In vitro susceptibility of Candida albicans to four disinfectants and their combinations. International Endodontic Journal, 32, 421–429 1999.

Aim The aim of this study was to evaluate the susceptibility of seven strains of Candida albicans to four disinfectants: iodine potassium iodidea, chlorhexidine acetate, sodium hypochlorite and calcium hydroxide. In addition, all possible pairs of the disinfectants were tested in order to compare the effect of the combination and its components.

Methodology Filter paper discs were immersed in standardized yeast suspensions and then transferred to disinfectant solutions of different concentrations and incubated at 378C for 30 s, 5 min, 1 h and 24 h. After incubation the filter paper discs were transferred to vials with PBS and glass beads that were then vigorously shaken for dispersal of the yeast cells. PBS with resuspended yeasts was serially diluted 10‐fold. Droplets of 25 μL from each dilution were inoculated on TSB agar plates and incubated in air at 378C for 24 h. The number of colony‐forming units was then calculated from appropriate dilutions.

Results  C. albicans cells were highly resistant to calcium hydroxide. Sodium hypochlorite (5% and 0.5%) and iodine (2%) potassium iodide (4%) killed all yeast cells within 30 s, whilst chlorhexidine acetate (0.5%) showed complete killing after 5 min. Combinations of disinfectants were equally or less effective than the more effective component. All C. albicans strains tested showed similar susceptibility to the medicaments tested.

Conclusions This study indicates that sodium hypochlorite, iodine potassium iodide and chlorhexidine acetate are more effective than calcium hydroxide against C. albicans in vitro. However, combining calcium hydroxide with sodium hypochlorite or chlorhexidine may provide a wide‐spectrum antimicrobial preparation with a long‐lasting effect.
A comparison in vitro of fibroblast attachment to resected root‐ends
Authors: Weston G. D. , Moule A. J. , Bartold P. M.
Published: March 2003

Weston GD, Moule AJ, Bartold PM. A comparison in vitro of fibroblast attachment to resected root‐ends. International Endodontics Journal, 32, 444–449 1999.

Aim The aim of this study was to investigate the effect of surface morphology of root ends resected with various bur configurations on fibroblast attachment.

Methodology Seventy‐two human single‐rooted teeth were collected and decoronated. The root canals were instrumented, and then obturated with thermoplasticized gutta‐percha using AH‐26 as the sealer. The roots were randomly divided into eight different groups, and apical root‐end resections were performed using eight different instruments, which included high and low speed burs and a scalpel blade. After each root was resected, the surface area of the root end was measured. Cultured human periodontal ligament fibroblasts were radiolabelled and then allowed to attach, in vitro, to the root‐ends. Cell attachment to the resected root‐ends was determined by counting in a liquid scintillation system and expressed as the number of decays per min/mm2 (DPM/mm2) of root surface.

Results There was no significant difference in fibroblast attachment to the root‐ends prepared with various instruments.

Conclusions These findings indicate that the choice of instrument for root‐end resection has little influence on the initial attachment of fibroblasts, and thus may have little effect on healing following root‐end resection.
Effects of alternating and direct electrical current application on the odontoblastic layer in human teeth: an in vitro study
Authors: Alwas‐Danowska H. M. , Huysmans M.‐C. D. N. J. M. , Verdonschot E. H.
Published: March 2003

Alwas‐Danowska HM, Huysmans M‐CDNJM, Verdonschot EH. Effects of alternating and direct electrical current application on the odontoblastic layer in human teeth: an in vitro study. International Endodontic Journal, 32, 459–463 1999.

Aim The aim of this study was to investigate the influence of a low intensity alternating current on the odontoblasts and odontoblast layer and compare this with the effects of a direct current.

Methodology Teeth extracted for orthodontic reasons were immersed in physiological saline stabilized with thymol crystals. Within 1h of extraction, an alternating or direct current was applied on the crown in the direction of the apex of the tooth for 120–360s. The current doses were 12, 30, 60, 600 1800, 3600, 7200, 24 000 and 144000 μC. The teeth were fixed in Bouin or Baker fluids, the pulps removed, dehydrated and immersed in paraffin, then sectioned, stained with haematoxylin and eosin, and studied under a light microscope.

Results Neither direct nor alternating current, similar to that applied in electrical caries diagnosis caused histological changes in the odontoblasts.

Conclusions There was no difference between direct and low intensity alternating current in the response of the odontoblast.
Reliability of radiographic observations recorded on a proforma measured using inter‐ and intra‐observer variation: a preliminary study
Authors: Saunders M. B. , Gulabivala K. , Holt R. , Kahan R. S.
Published: March 2003

Aim  The aim of this preliminary study was to test the reliability of radiographic evaluation of features of endodontic interest using a newly devised data collection system

Methodology  Twelve endodontic MSc postgraduate students and one specialist endodontist examined sample radiographs derived from a random selection of 42 patients seen previously on an Endodontic New Patient Clinic (EDI). Each student examined a random selection of 8–9 roots on periapical radiographs of single‐ and multirooted teeth, with and without previous root canal therapy and 3–4 dental panoramic tomograms (DPTs). A total of 100 roots were examined. A proforma was used to record observations on 67 radiographic features using predefined criteria. Intra‐observer agreement was tested by asking the students to re‐examine the radiographs. The principle investigator and the specialist endodontist examined the same radiographs and devised a Gold Standard using the same criteria. This was compared with the student assessments to determine inter‐observer variation. The postgraduates then attended a revision session on the use of the form. Each student subsequently examined 8–9 different roots from the pool of radiographs. A further assessment of inter‐observer variation was made by comparing these observations with the Gold Standard.

Results  Of the 67 radiographic features, only 25 had sufficient response to allow statistical analysis. Kappa values for intra‐ and inter‐observer variation were estimated. These varied depending on the particular radiographic feature being assessed. Fifteen out of 25 intra‐observer recordings showed ‘good’ or ‘very good’ Kappa agreement, but only three out of 25 inter‐observer observations achieved ‘good’ or ‘very good’ values. Inter‐observer variation was improved following the revision session with 16 out of 25 observations achieving ‘good’ or ‘very good’ Kappa agreement.

Conclusions  Modification to the proforma, the criteria used, and training for radiographic assessment were considered necessary to improve the accuracy and reproducibility of the observations entered.
Evaluation of apical sealing of three endodontic sealers
Authors: De Almeida W. A. , Leonardo M. R. , Filho M. Tanomaru , Silva L. A. B.
Published: March 2003

De Almeida WA, Leonardo MR, Tanomaru Filho M, Silva LAB. Evaluation of apical sealing of three endodontic sealers. International Endodontic Journal, 33, 25–27, 2000.

Aim  The apical sealing ability of three different endodontic sealers was evaluated in extracted teeth using dye penetration.

Methodology The root canals of 99 extracted human maxillary central incisors were prepared sequentially 2mm beyond the apical foramen with a size 55 Nitiflex file. The teeth were divided into three experimental groups and obturated by lateral condensation of cold gutta‐percha and one of the following sealers: group 1, zinc oxide and eugenol sealer (Fill Canal); group 2, glass ionomer sealer (Ketac‐Endo) and group 3, epoxy resin sealer (AH Plus). The teeth were covered with nail varnish to within 1mm of the apical foramen and immersed in 2% methylene blue in a

reduced pressure environment for 24h. After this period, the teeth were washed and cut longitudinally for apical leakage analysis. The values were obtained from the maximum depth of leakage as well as the average between the maximum and minimum values observed for each group.

Results  Statistical evaluation of the results showed no significant difference in the leakage between Fill Canal and Ketac‐Endo (P >0.05). Leakage with AH Plus was significantly less (P <0.01) than with the other sealers.

Conclusions  All three sealers allowed some leakage to occur. Leakage with AH Plus was significantly different than with Fill Canal or Ketac‐Endo.
Detection of a transitional ion concentration zone during electronic measurement of root canal length: a study in vitro
Authors: Tamarut T. , Kovačević M. , Uhač I.
Published: March 2003

Aim

The aim of this study was to examine the importance of a transitional ion concentration zone at the apical foramen during electronic root canal length measurement (ERCLM).

Methodology

The model comprised 21 extracted single‐rooted human teeth, divided into two experimental groups and one control group, each of seven teeth. The anatomical tooth length was determined from the site of reference on the tooth crown to the canal orifice and was measured using an endodontic file and a vernier caliper. Two aqueous solutions of various NaCl, KCl and CaCl2 concentrations were mixed with agar. The Na+, K+ and Ca++ concentrations corresponded to the average value of each group as determined by atomic spectrophotometry evaluation of the extirpated human pulps. The agar containing cations was injected into the root canals after their preparation to a foramen diameter of 0.70 mm. The control teeth were then completely immersed in agar having the same concentration of cations as the agar inside the canal. In the first experimental group (group 1), the teeth were immersed in agar so that the ion concentration was higher inside the canal; in the second experimental group (group 2), the concentrations were reversed. In all three groups, ERCLM was performed by an EED 11 – resistance type device. Length d1 was defined as the length of the root when measured to a value one degree less than the test value. Length d2 was defined as the length of the root inducted by the test value, which corresponded to the resistance of the periapical agar.

Results

In group 1 the average d1 length was 0.44 ± 1.05 shorter than the anatomical foramen (AF), and in group 2, 1.11 ± 0.43 mm longer than AF. In the control group the d1 length was on average − 3.02 ± 3.72 mm from the AF. The d1 values of all groups were not statistically significantly different from the anatomical length (AL). In all three experimental groups the d2 length was statistically significantly different from the AL (P < 0.05, t‐test); group 1 d2 = AL + 6.32 ± 1.38 mm; group 2 d2 = AL + 6.27 ± 1.47; control group d2 = AL + 9.15 ± 1.00 mm.

Conclusions

The results of this study indicated that when the electroconductive medium in the canal had a different ion concentration than the periapex, and the canal orifice had a wide diameter (0.70 mm), the transitional concentration zone influenced the accuracy of measurement during ERCLM with a resistance type device. When ion concentrations inside and outside the canal were identical, in teeth with a wide foramen diameter (0.70 mm or more) the lack of a transitional ion concentration zone meant that the length of the root canal could not be determined by ERCLM.
Endodontic teaching in Philippine dental schools
Authors: Cruz E. V. , Jimena M. E. M. , Puzon E. G. , Iwaku M.
Published: March 2003

Aim

The aim of this study was to evaluate the pattern of undergraduate endodontic teaching in Philippine dental schools.

Methodology

Data were gathered by sending questionnaires to the deans of the 23 dental schools in the country to determine details of the teaching of root canal treatment in permanent teeth. The covering letter requested that endodontic staff complete the questionnaire.

Results

Twenty of 23 dental schools returned completed questionnaires. Similarities were observed in the timing of undergraduate endodontic teaching, working length determination, and root canal preparation technique. Irrigating fluids recommended included one or a combination of the following: sodium hypochlorite, hydrogen peroxide, distilled water and EDTA. The root canal medicaments popularly employed were CMCP and eugenol. Most schools used slow‐setting zinc oxide eugenol cement as sealer. Differences between schools were noted in the laboratory component of the course. The time allotted for the laboratory exercises, as well as the number of teeth used, differed greatly between each school. An inadequate tutor to student ratio was noted in the majority of schools. Teaching aids were limited and, in most instances, produced by faculty members. Most faculty members teaching endodontics had no specialist training.

Conclusion

The results of this study have demonstrated that there is a need to review endodontic teaching in the majority of the Philippine dental schools to ensure that the course content and curriculum employed by all schools meet specified standards and that appropriate measures should be considered to enhance the learning experience of students.
An unusual case of furcation external resorption
Authors: Wood P. , Rees J. S.
Published: March 2003

Aim

To describe the presentation and management of an unusual external root resorption.

An unusual external inflammatory root resorption presented in the furcation of a mandibular first molar. Review of earlier radiographs suggested that the lesion was non‐progressive. Occlusal trauma associated with anterior open bite was the most likely aetiological factor. No active treatment was prescribed.

Key learning points

External resorption may occur following loss of the external root surface.

Occlusal trauma may be a propagating stimulus for progressive resorption.

Lesions may sometimes be non‐progressive, and treatment may therefore be more damaging than observation.
The use of calcium sulphate in the surgical treatment of a ‘through and through’ periradicular lesion
Authors: Pecora G. , De Leonardis D. , Ibrahim N. , Bovi M. , Cornelini R.
Published: March 2003

Aim This randomized, controlled, clinical study was designed to evaluate the adjunctive effect of calcium sulphate grafts on the surgical treatment of through and through periradicular lesions.

Methodology  Twenty patients each with one tooth showing evidence radiologically of a periradicular lesion wider than 10 mm, with lack of both buccal and lingual cortical bony plates and an indication for surgery were selected for the study. Ten teeth were treated with apicectomy, root‐end filling and grafting of the bone defect with calcium sulphate prior to suturing (test group). The other 10 teeth received the same surgical therapy but no grafting with calcium sulphate (control group). The outcome of the healing process was evaluated at 6 and 12 months radiographically following the criteria reported by Rud and Andreasen.

Results At the six‐ and 12‐month evaluation the test group had seven teeth with complete healing and two with incomplete healing, whilst the control group showed three teeth with complete healing, five with incomplete healing and one with unsatisfactory healing. One tooth in each group had to be extracted because of a vertical fracture that occurred during the follow‐up period.

Conclusions  The results of the study demonstrate that the addition of calcium sulphate as a bone graft during the conventional surgical treatment of through and through lesions improves the clinical outcome. Histological analysis is desirable to investigate the quality of tissues formed using the two surgical procedures.