bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of cytoplasmic CD antigens within normal human peripheral blood leucocytes
Authors: Sandilands Gavin P. , Hauffe Birgit , Loudon Elizabeth , Marsh Andrew G. , Gondowidjojo Anna , Campbell Carol , Ferrier Roderick K. , Rodie Martina E.
Published: March 2003

Polymorphonuclear neutrophils (PMNs) are capable of synthesizing various pro‐inflammatory cytokines which may indirectly influence specific immune responses. PMNs may also have the capacity to present foreign peptides to helper T cells (Th cells). In support of this hypothesis, recent studies have shown that neutrophils, when activated by the correct combination of cytokines, can be induced to express cell surface major histocompatibility complex (MHC) Class II (DR) antigen, CD80 (B7.1) and CD86 (B7.2): molecules required for antigen presentation and subsequent T‐cell activation. In this study we have used normal ‘resting’ human peripheral blood neutrophils and demonstrated, using a mild fixation and permeabilization protocol, significant cytoplasmic ‘stores’ of these molecules known to be important in antigen presentation. Cytoplasmic MHC Class II antigen was found with two out of 20 normal donors tested whereas cytoplasmic CD80 and CD86 were found to a variable extent within all normal donors. Surprisingly, we also found several other neutrophil cytoplasmic CD antigens more commonly associated with B cells, i.e. CD20, CD21 (CR2/EBV‐R) and CD22 (BL‐CAM). All of these antigens were confined to the ‘resting’ cell cytoplasm and were never found to be expressed on the cell surface. To exclude the possibility that these antigens were absorbed from plasma and to provide evidence for active synthesis, we used a novel whole blood in situ hybridization flow cytometry assay method to detect mRNA specific for these antigens within normal PMNs. We also conducted real‐time polymerase chain reactions to confirm these findings using CD22 as a good example of an ‘inappropriately expressed’ CD antigen. These observations therefore provide support for the hypothesis that human PMNs have the potential to express molecules required for antigen presentation and cell signalling.
Oestrogen receptor specificity in oestradiol‐mediated effects on B lymphopoiesis and immunoglobulin production in male mice
Authors: Erlandsson M. C. , Jonsson C. A. , Islander U. , Ohlsson C. , Carlsten H.
Published: March 2003

Oestrogen treatment down‐regulates B lymphopoiesis in the bone marrow of mice. Meanwhile it up‐regulates immunoglobulin production. To understand better the oestrogen action on bone marrow male mice lacking oestrogen receptor α (ERα; ERKO mice), lacking ERβ (BERKO mice), lacking both receptors (DERKO mice) or wild‐type (wt) littermates were castrated and treated for 2·5 weeks with 30 μg/kg 17β‐oestradiol (E2) or vehicle oil as controls. The B lymphopoiesis in the bone marrow was examined by flow cytometry and mature B‐cell function was studied using an ELISPOT assay enumerating the B cells in bone marrow and spleen that were actively producing immunoglobulins. In wt mice the frequency of B‐lymphopoietic (B220+) cells in the bone marrow decreased from 15% to 5% upon E2 treatment. In ERKO and BERKO mice significant reduction was seen but not of the same magnitude. In DERKO mice no reduction of B lymphopoiesis was seen. In addition, our results show that E2 mediated reduction of different steps in B lymphopoiesis require only ERα or both receptors. In wt and BERKO mice E2 treatment resulted in significantly increased levels of B cells actively producing immunoglobulin, while in ERKO and DERKO mice no such change was seen. Similar results were found in both bone marrow and spleen. In conclusion our results clearly show that both ERα and ERβ are required for complete down‐regulation of B lymphopoiesis while only ERα is needed to up‐regulate immunoglobulin production in both bone marrow and spleen.
Qualitative research: meanings or practices?
Authors: Silverman D.
Published: March 2003

With information systems (IS), as in other social sciences, the critique of quantitative research can lead to an oversimplified opposition between ‘positivism’ and ‘interpretivism’. This is one reason why qualitative IS research sometimes unnecessarily limits itself to the study of participants' meanings. A simple tabulation of published qualitative research is used to reveal the predominance of interview‐based studies in both sociology and IS. This is followed by a brief account of the limits of both quantitative studies of ‘objective’ variables and qualitative studies of ‘subjective meanings’. The emerging case for IS research on organizational practices is set out, coupled with an account of Suchman's (1987) study of how workers make use of a computer‐based system attached to a photocopier. The paper concludes with a call for an end to paradigm wars in organizational studies.
Interfirm collaboration through interfirm networks
Authors: Li Feng , Williams Howard
Published: March 2003

Abstract. Abstract. Since the late 1980s, interfirm (computer) networks have been diffusing very rapidly. They have not only been adopted by firms across the whole spectrum of sectors; the applications based on such networks have also been extended from routine transactions to strategically more important processes. Using recent evidence gathered from six in‐depth cases studies in the UK and a telephone‐based survey, this paper will illustrate how the development of interfirm networks has facilitated the emergence of new interfirm collaboration in strategic areas. The empirical evidence has been drawn from the retailing, motor manufacturing and electronics industries. To conclude, the paper will highlight several key issues that have emerged from the study, identify three layers of barriers to the development of interfirm networks, and outline a future research agenda.
A new framework for managing IT‐enabled business change
Authors: Ward John , Elvin Roger
Published: March 2003

Abstract. Although information systems and technology (IS/IT) investments have always caused varying degrees of business change, the main purpose of many of today’s IS/IT implementations is to change the business and/or organization in some significant way. However, most organizations’ approaches to managing IS/IT developments have changed little in the last 15–20 years and are heavily dependent on methodologies of IS/IT development and associated project management principles. The philosophy being adopted by many organizations today is that there are few IS/IT projects (some infrastructure investments only) that do not cause business changes and therefore they are really ‘business projects involving IS/IT’. This exploratory research set out to devise a new framework for ‘IT and change’ management, which is more appropriate to today’s realities than traditional approaches. The initial framework was derived from ‘first principles’, then adapted and further developed by applying and testing it in a range of real projects in organizations. This paper summarizes the results of that work.
Virtual team effectiveness: a proposed research agenda
Authors: Furst Stacie , Blackburn Richard , Rosen Benson
Published: March 2003

Abstract. Contemporary competitive demands have forced many organizations to increase levels of flexibility and adaptability in their operations. A growing number of such organizations have explored the virtual environment as one means of achieving increased responsiveness. In particular, the use of virtual teams appears to be on the increase. However, the increased use of virtual teams has not been accompanied by concomitant research efforts to understand better the social‐psychological contributors to effective virtual teams. In this paper, we use a model of group effectiveness to propose a possible research agenda examining sources of virtual team effectiveness. Although much of this model offers insights relevant to the virtual environment, differences between groups and teams and between co‐located and virtual environments suggest that modifications and additions to this model may be necessary. We offer a set of research propositions to advance future research on effective virtual teams beyond anecdote and description. Implications of this research agenda for managers of virtual teams and human resource professionals are also discussed.
Molecular characterization of pyrethroid knockdown resistance (kdr) in the major malaria vector Anopheles gambiae s.s.
Authors: Martinez‐Torres D. , Chandre F. , Williamson M. S. , Darriet F. , Bergé J. B. , Devonshire A. L. , Guillet P. , Pasteur N. , Pauron D.
Published: March 2003

Pyrethroid‐impregnated bednets are playing an increasing role for combating malaria, especially in stable malaria areas. More than 90% of the current annual malaria incidence (c. 500 million clinical cases with up to 2 million deaths) is in Africa where the major vector is Anopheles gambiae s.s. As pyrethroid resistance has been reported in this mosquito, reliable and simple techniques are urgently needed to characterize and monitor this resistance in the field. In insects, an important mechanism of pyrethroid resistance is due to a modification of the voltage‐gated sodium channel protein recently shown to be associated with mutations of the para‐type sodium channel gene. We demonstrate here that one of these mutations is present in certain strains of pyrethroid resistant A. gambiae s.s. and describe a PCR‐based diagnostic test allowing its detection in the genome of single mosquitoes. Using this test, we found this mutation in six out of seven field samples from West Africa, its frequency being closely correlated with survival to pyrethroid exposure. This diagnostic test should bring major improvement for field monitoring of pyrethroid resistance, within the framework of malaria control programmes.
DNA structures common for chironomid telomeres terminating with complex repeats
Authors: Rosén M. , Edström J.‐E.
Published: March 2003

Tandem repeats, 340 bp long, have been shown to terminate the chromosomes in Chironomus pallidivittatus and similar DNA may be used for this purpose by related insects. In view of the importance of Chironomus in telomere studies, representing in principle a third system after short repeats and Drosophila telomeric retrotransposons, we have investigated the related Chironomus dilutus, to learn what DNA structures are conserved at the chromosome ends. Interspersed subrepeats in the telomeric repeats, which contain a long palindrome, and a zone of about 100 bp of relatively constant subtelomeric DNA towards the junction to the telomeric DNA, are characteristic for C. dilutus as for previously investigated species. C. dilutus has similar subtelomeric DNA at all chromosome ends, but typical telomeric repeats in only seven of the pairs since the eighth telocentric pair contains centromere‐specific repeats.
Persistence of Anopheles arabiensis during the severe dry season conditions in Senegal: an indirect approach using microsatellite loci
Authors: Simard Frédéric , Lehmann Tovi , Lemasson, Jean‐Jacques , Diatta Mathurin , Fontenille Didier
Published: March 2003

Variation at nine microsatellite loci was investigated to understand how Anopheles arabiensis populations survive the dry season in the sahelian region of Senegal. Low estimates of genetic differentiation (FST = 0.012, RST = 0.009) between two populations, 250 km apart, suggested extensive gene flow across this distance. Despite extreme seasonal fluctuation in abundance with dry season minima in which mosquitoes virtually disappeared, allele frequencies remained stable over time in the village of Barkedji from August 1994 to December 1997 (including four rainy seasons and three dry seasons). The effective population size (Ne) was estimated to be 601 with 95% CI (281, 1592), providing strong evidence against annual bottlenecks. Differences in measures of genetic diversity and linkage disequilibrium between the dry and the rainy seasons were not detected. These results suggest that despite extreme minima in local density, An. arabiensis maintains large permanent deme spread out over large area.
The mitochondrial genome of the primary screwworm fly Cochliomyia hominivorax (Diptera: Calliphoridae)
Authors: Lessinger A. C. , Martins Junqueira A. C. , Lemos T. A. , Kemper E. L. , Da Silva F. R. , Vettore A. L. , Arruda P. , L. Azeredo‐Espin A. M.
Published: March 2003

The complete sequence of the mitochondrial genome of the screwworm Cochliomyia hominivorax was determined. This genome is 16 022 bp in size and corresponds to a typical Brachycera mtDNA. A Serine start codon for COI and incomplete termination codons for COII, NADH 5 and NADH 4 genes were described. The nucleotide composition of C. hominivorax mtDNA is 77% AT‐rich, reflected in the predominance of AT‐rich codons in protein‐coding genes. Non‐optimal codon usage was commonly observed in C. hominivorax mitochondrial genes. Phylogenetic analysis distributed the Acalypterate species as a monophyletic group and assembled the C. hominivorax (Calyptratae) and the Acalyptratae in a typical Brachycera cluster. The identification of diagnostic restriction sites on the sequenced mitochondrial genome and the correlation with previous RFLP analysis are discussed.
Wolbachia neither induces nor suppresses transcripts encoding antimicrobial peptides
Authors: Bourtzis K. , Pettigrew M. M. , O’Neill S. L.
Published: March 2003

Wolbachia are intracellular maternally inherited microorganisms that are associated with reproductive abnormalities such as cytoplasmic incompatibility (CI), feminization and parthenogenesis in the various arthropod species they infect. Surveys indicate that these bacteria infect more than 16% of all insect species as well as isopods, mites and nematodes, making Wolbachia one of the most ubiquitous parasites yet described. However, nothing is known about the interactions of this bacterium with the host’s immune system. We studied the expression of inducible antimicrobial markers in the adults of two Wolbachia infected insect species, Drosophila simulans and Aedes albopictus. The lack of available immune markers in the mosquito species led us to clone part of the defensin gene from this species, which was found to be very similar to the other mosquito defensins cloned from Anopheles gambiae and Aedes aegypti. Comparisons of the expression pattern of the antibacterial markers between Wolbachia‐infected and cured lines, and also between bacteria‐challenged and unchallenged adults indicated that Wolbachia does not either constitutively induce or suppress the transcription of these antibacterial genes. In addition, no difference in the transcription of these genes was found between double and single Wolbachia‐infected strains or between strains in which Wolbachia has different tissue tropisms.
Molecular characterization of two serine proteases expressed in gut tissue of the African trypanosome vector, Glossina morsitans morsitans
Authors: Yan Jian , Cheng Qiuying , Li Chang‐Ben , Aksoy Serap
Published: March 2003

Serine proteases are major insect gut enzymes involved in digestion of dietary proteins, and in addition they have been implicated in the process of pathogen establishment in several vector insects. The medically important vector, tsetse fly (Diptera:Glossinidiae), is involved in the transmission of African trypanosomes, which cause devastating diseases in animals and humans. Both the male and female tsetse can transmit trypanosomes and both are strict bloodfeeders throughout all stages of their development. Here, we describe the characterization of two putative serine protease‐encoding genes, Glossina serine protease‐1 (Gsp1) and Glossina serine protease‐2 (Gsp2) from gut tissue. Both putative cDNA products represent prepro peptides with hydrophobic signal peptide sequences associated with their 5′‐end terminus. The Gsp1 cDNA encodes a putative mature protein of 245 amino acids with a molecular mass of 26 428 Da, while the predicted size of the 228 amino acid mature peptide encoded by Gsp2 cDNA is 24 573 Da. Both deduced peptides contain the Asp/His/Ser catalytic triad and the conserved residues surrounding it which are characteristic of serine proteases. In addition, both proteins have the six‐conserved cysteine residues to form the three‐cysteine bonds typically present in invertebrate serine proteases. Based on the presence of substrate specific residues, the Gsp1 gene encodes a chymotrypsin‐like protease while Gsp2 gene encodes for a protein with trypsin‐like activity. Both proteins are encoded by few loci in tsetse genome, being present in one or two copies only. The mRNA expression levels for the genes do not vary extensively throughout the digestive cycle, and high levels of mRNAs can be readily detected in the gut tissue of newly emerged flies. The levels of trypsin and chymotrypsin activities in the gut lumen increase following blood feeding and change significantly in the gut cells throughout the digestion cycle. Hence, the regulation of expression for trypsin and chymotrypsin occurs at the post‐transcriptional level in tsetse. Both the coding sequences and patterns of expression of Gsp1 and Gsp2 genes are similar to the serine proteases that have been reported from the bloodfeeding insect Stomoxys calcitrans.
Inhibition of the lepidopteran amino acid co‐transporter KAAT1 by phenylglyoxal: role of arginine 76
Authors: Castagna Michela , Vincenti Sergio , Marciani Paola , Sacchi V. Franca
Published: March 2003

Phenylglyoxal (PGO), an arginine‐modifying reagent, is an irreversible inhibitor of KAAT1‐mediated leucine transport, expressed in Xenopus oocytes. The PGO effect was dose‐dependent and 5 mm PGO determined a Vmax reduction to 24% of the control, consistent with the covalent binding to transporter arginine residues not located in the leucine binding site. The use of labelled [14C]PGO confirmed that the inhibitor binds KAAT1. The protein membrane domain contains seven arginine residues one of which, arginine 76, is conserved in the family of GABA transporters. Using site‐directed mutagenesis we showed that only arginine 76 is crucial for KAAT1 activity and is involved in PGO binding.
Differentially expressed midgut transcripts inCulicoides sonorensis(Diptera: Ceratopogonidae) following Orbivirus (Reoviridae) oral feeding
Authors: Campbell C. L. , Wilson W. C.
Published: March 2003

Understanding the vector insect's gene expression response to a virus infection may aid design of control measures for arbovirus diseases.Culicoides sonorensisis a vector of several agriculturally important pathogens, such as epizootic haemorrhagic disease virus (EHDV) that causes disease in ruminants. Two approaches, differential display and suppression subtractive hybridization, were used to identify 400+Culicoidestranscripts that were more abundant in midguts 1 day following an oral meal containing EHDV. Of these, quantitative PCR confirmed seven to be more abundant in virus‐fed midguts than controls. One such transcript encodes a putative RNA editase, CsRED1, induced by dsRNA. Transcripts encoding putative receptors involved in cell differentiation included CsLAR, a protein tyrosine phosphatase, and CsFZ2, homologous to thewinglessreceptor inD. melanogaster. Transcripts encoding putative translation machinery components included CseIF3, CseIF5A and CsRPS6. Overall, the cDNA fragments identified in this study increased in the midgut at one day postfeeding; by 2 days postfeeding, increases in transcript levels shifted from the midgut to the remainder of the infected midge.
Bacterial eradication from root dentine by ultrasonic irrigation with sodium hypochlorite
Authors: Huque  , Kota  , Yamaga  , Iwaku  , Hoshino
Published: March 2003

The study aimed to evaluate intracanal irrigation procedures in eradicating bacteria from surface, shallow and deep layers of root dentine using extracted human teeth. Artificial bacterial smear layer was successfully produced by rubbing a mixture of dental plaque and artificially decalcified dentine or carious dentine on root canal walls. The reservoir holes were 3.5 mm in depth, 1 mm in diameter prepared 1.5 mm apart and parallel to the root canals on the decrowned planes, in which five separate bacterial species were placed (Actinomyces israelii, Fusobacterium nucleatum, Propionibacterium acnes, Streptococcus mutans and Streptococcus sanguis). Bacterial eradication after irrigation of the prepared canals was determined by bacterial recovery (i) from the root canal surfaces and shallow layers where bacteria were smeared artificially and (ii) from deeper layers of root canal dentine reservoir holes.

Ultrasonic irrigation with 5.5% and 12% NaOCl eradicated bacteria from artificial smear layer (P<0.0001), whilst 12% NaOCl irrigation with a syringe was insufficient. Ultrasonic irrigation with water or 15% EDTA failed to eradicate bacteria from smeared surfaces. Ultrasonic irrigation with 12% NaOCl killed A. israelii, F. nucleatum, P. acnes, S. mutans, and S. sanguis placed in reservoir channels, although for F. nucleatum, a very small number of bacteria remained in five samples out of 12. Ultrasonic irrigation with less concentrated NaOCl failed to eliminate bacteria completely from reservoir channels in most samples. Ultrasonic irrigation with 12% NaOCl appeared to eliminate bacteria efficiently from surface, shallow and deep layers of root dentine.
Gaining access through a calcified pulp chamber: a clinical challenge
Authors: Ngeow  , Thong
Published: March 2003

Dental pulp is prone to dystrophic mineralization; this mineralization can be so extensive that the entire root canal system is obliterated. As a result, root canal treatment can become a difficult if not impossible task. This article presents the endodontic management of a tooth with an obliterated pulp chamber and associated with a discharging sinus in a teenage patient. The role of a calcium hydroxide lining to induce mineralization and cause the obliteration of the pulpal space is also discussed.
Diminished leakage along root canals filled with gutta‐percha without sealer over time: a laboratory study
Authors: Wu M. ‐K. , Fan B. , Wesselink P. R.
Published: March 2003

Aim  The aim of this study was to investigate the long‐term seal of gutta‐percha (GP) without sealer.

Methodology Extracted human maxillary central incisors were prepared and obturated using heat‐ or chloroform‐softened GP only, or GP in combination with a root canal sealer. Leakage along root fillings was measured at 48 h and after a period of 6 months using a fluid transport model.

Results  At 48 h the GP‐filled roots without sealer leaked more than the control roots filled with GP and sealer (P <0.0001). At 6 months a significant reduction in leakage was found in the GP‐only groups (P< 0.05 for both heat‐ and chloroform‐softened GP). After 6 months, roots filled by vertical condensation of GP‐only had similar leakage as vertically condensed GP with a sealer (P >0.05).

Conclusions  The long‐term seal of root fillings is affected by the volume change of both GP and sealer. Leakage reduction due to expansion of GP may compensate to a certain extent for leakage that may occur from sealer dissolution.
Comparison of cold lateral condensation and a warm multiphase gutta‐percha technique for obturating curved root canals
Authors: Gilhooly R. M. P. , Hayes S. J. , Bryant S. T. , Dummer P. M. H.
Published: March 2003

Aim

The aim of this project was to evaluate and compare the radiographic quality and sealability of root fillings in extracted human teeth using lateral condensation of gutta‐percha or multiphase gutta‐percha obturation (Alphaseal).

Methodology

A total of 108 freshly extracted human, mature single‐rooted teeth were divided into two identical groups of 54 teeth on the basis of root canal shape. The canals were prepared to a minimum 0.055 taper and enlarged to size 35 at the apex. All root canals were flushed with 17% EDTA solution and 2.5% NaOCl to remove the dentinal smear layer. The canals of one group were obturated using cold lateral condensation of gutta‐percha and the canals of the other group were filled using a warm multiphase gutta‐percha obturation technique. The extrusion of sealer and/or gutta‐percha through the apex of the teeth was recorded using a simple yes/no scheme. The sealability of each technique was assessed by a dye penetration method. The radiographic quality of obturation was determined for each canal using a four‐point scale.

Results

Root canals filled by multiphase obturation had significantly more extrusion of sealer (P < 0.001) and gutta‐percha (P < 0.001) than canals filled by lateral condensation. Canals filled by multiphase gutta‐percha obturation had significantly less apical dye leakage than those obturated by lateral condensation (P < 0.05). Lateral condensation achieved significantly better scores for radiographic quality than multiphase obturation from the bucco‐lingual view (P < 0.01).

Conclusions

Under laboratory conditions multiphase gutta‐percha had better sealability but poorer radiographic quality than lateral condensation.
An overview of nickel–titanium alloys used in dentistry
Authors: Thompson S. A.
Published: March 2003

Thompson SA.

An overview of nickel–titanium alloys used in dentistry. International Endodontic Journal, 33, 297–310, 2000.

Literature review

The nickel–titanium alloy Nitinol has been used in the manufacture of endodontic instruments in recent years. Nitinol alloys have greater strength and a lower modulus of elasticity compared with stainless steel alloys. The super‐elastic behaviour of Nitinol wires means that on unloading they return to their original shape following deformation. These properties are of interest in endodontology as they allow construction of root canal instruments that utilize these favourable characteristics to provide an advantage when preparing curved canals. This review aims to provide an overview of Nitinol alloys used in dentistry in order for its unique characteristics to be appreciated.
The structure of dentine in the apical region of human teeth
Authors: Mjör I. A. , Smith M. R. , Ferrari M. , Mannocci F.
Published: March 2003

Aim

To study the structure of the apical region of human teeth with emphasis on dentinal tubules and their branches.

Methodology

This descriptive histological study employed demineralized stained sections for light microscopy, demineralized unstained sections for scanning electron microscopy, and undemineralized, acid‐etched specimens for confocal tandem scanning microscopy.

Results

The apical portion of human teeth showed marked variations in structure, including accessory root canals, areas of resorption and repaired resorptions, occasional attached, embedded and free pulp stones, varied amounts of irregular secondary dentine, and even cementum‐like tissue lining the apical root canal wall. The apex often deviated from the long axis of the root canal. Primary dentinal tubules were irregular in direction and density. Some areas were devoid of tubules.

Conclusions

The irregular and variable structure of the apical region of human teeth represent special challenges during endodontic therapy. Obturation techniques based on the penetration of adhesives into dentinal tubules are unlikely to be successful and adhesive techniques must depend on impregnation of a hybrid layer.
In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis
Authors: Gomes B. P. F. A. , Ferraz C. C. R. , M. E. Vianna , Berber V. B. , Teixeira F. B. , Souza‐Filho F. J.
Published: March 2003

Aim

The aim of this study was to assess, in vitro, the effectiveness of several concentrations of NaOCl (0.5%, 1%, 2.5%, 4% and 5.25%) and two forms of chlorhexidine gluconate (gel and liquid) in three concentrations (0.2%, 1% and 2%) in the elimination of E. faecalis.

Methodology

A broth dilution test using 24‐well cell culture plates was performed and the time taken for the irrigants to kill bacterial cells was recorded. Isolated 24 h colonies of pure cultures of E. faecalis grown on 10% sheep blood plus Brain Heart Infusion (BHI) agar plates were suspended in sterile 0.85% NaCl solution. The cell suspension was adjusted spectrophotometrically to match the turbidity of a McFarland 0.5 scale. One mL of each tested substance was placed on the bottom of wells of 24‐well cell culture plates (Corning, NY), including the control group (sterile saline). Six wells were used for each time period and irrigant concentration. Two mL of the bacterial suspension were ultrasonically mixed for 10 s with the irrigants and placed in contact with them for 10, 30, and 45 s; 1, 3, 5, 10, 20, and 30 min; and 1 and 2 h. After each period of time, 1 mL from each well was transferred to tubes containing 2 mL of freshly prepared BHI + neutralizers in order to prevent a residual action of the irrigants. All tubes were incubated at 37°C for 7 days. The tubes considered to have positive growth were those which presented medium turbidity during the incubation period. Data were analysed statistically by the Kruskal–Wallis test, with the level of significance set at P < 0.05.

Results

All irrigants were effective in killing E. faecalis, but at different times. Chlorhexidine in the liquid form at all concentrations tested (0.2%, 1% and 2%) and NaOCl (5.25%) were the most effective irrigants. However, the time required by 0.2% chlorhexidine liquid and 2% chlorhexidine gel to promote negative cultures was only 30 s and 1 min, respectively.

Conclusions

Even though all tested irrigants possessed antibacterial activity, the time required to eliminate E. faecalis depended on the concentration and type of irrigant used.
Efficacy of chemical sterilization and storage conditions of gutta‐percha cones
Authors: Da Motta P. G. , De Figueiredo C. B. O. , Maltos S. M. M. , Nicoli J. R. , Ribeiro Sobrinho A. P. , Maltos K. L. M. , Carvalhais H. P. M.
Published: March 2003

Aim

The objective of the present study was to assess the efficacy of 2.5% sodium hypochlorite and 2.2% glutaraldehyde (‘Cidex’) as sterilizing agents for gutta‐percha cones. The efficacy of storage of gutta‐percha cones in the presence or absence of paraformaldehyde was also evaluated.

Methodology

Gutta‐percha cones artificially contaminated with a suspension of Bacillus stearothermophilus (ATCC/7953) were treated with either 2.2% glutaraldehyde for 10, 15, 30 and 60 min and 10 and 12 h, or 2.5% sodium hypochlorite for 5, 10 and 15 min. The cones were then incubated in thioglycollate medium for the determination of microbial growth. In parallel, additional sterile gutta‐percha cones were stored in sealed containers with or without paraformaldehyde tablets for 30 days. The containers were opened 30 min a day and exposed to the environment of a functioning dental clinic. Twelve cones were removed weekly from the containers to determine whether contamination had occurred.

Results

The results showed that 2.5% sodium hypochlorite was effective after 5, 10 and 15 min, whereas 10 and 12 h contact with 2.2% glutaraldehyde was necessary to obtain sterilization. There was no contamination of the gutta‐percha cones when stored with or without paraformaldehyde.

Conclusions

Sodium hypochlorite (2.5%) and 2.2% glutaraldehyde (‘Cidex’) proved to be effective as sterilizing agents for gutta‐percha cones, with sodium hypochlorite requiring shorter periods of use. No difference was observed between the two methods of cone storage.
A reconstructed computerized tomographic comparison of Ni–Ti rotary GT™ files versus traditional instruments in canals shaped by novice operators
Authors: Gluskin A. H. , Brown D. C. , Buchanan L. S.
Published: March 2003

Aim

The aim of this study was to compare the effects of preparation with conventional stainless steel Flexofiles® and Gates Glidden burs versus nickel–titanium GT™ rotary files in the shaping of mesial root canals of extracted mandibular molars.

Methodology

A total of 54 canals from 27 mesial roots of mandibular molar teeth were prepared using one of two methods by novice dental students. One canal in each root was prepared by a crown‐down approach, utilizing stainless steel Flexofiles® and Gates Glidden burs. The other canal was prepared using nickel–titanium GT™ rotary files in a crown‐down fashion as recommended by the manufacturer. Preoperative CT scans of each root were recorded and 50 canal specimens were available for postoperative comparisons. Following canal shaping, postoperative scans were superimposed on the original images. Changes in canal area, canal transportation and thickness of remaining root structure at strategic levels of the root were analyzed. The time taken for each method was also noted.

Results

At the coronal and mid‐root coronal one‐third sections, the rotary GT™ files produced a significantly smaller postoperative canal area (P < 0.05). In the mid‐root sections there was significantly less transportation of the root canal toward the furcation, and less thinning of the root structure with GT™ files compared to the stainless steel files (P < 0.05). Overall, there was greater conservation of structure coronally and more adequate shape in the mid‐root level. The GT™ rotary technique was significantly faster than the stainless steel hand‐held file technique (P < 0.0001). Two GT™ instruments fractured during the study.

Conclusions

Under the conditions of this study, novice dental students were able to prepare curved root canals with Ni–Ti GT™ rotary files with less transportation and greater conservation of tooth structure, compared to canals prepared with hand instruments. The rotary technique was significantly faster.
A comparison of the quality of root canal treatment in two Danish subpopulations examined 1974–75 and 1997–98
Authors: Kirkevang L‐L. , Hörsted‐Bindslev P. , Ørstavik D. , Wenzel A.
Published: March 2003

Aim

The aim of this study was to compare the quality of root canal treatment in two Danish subpopulations.

Methodology

Group 1 (358 patients) was examined 1974–75 and group 2 (244 patients) 1997–98. All patients were more than 20 years old. All had undergone a full‐mouth radiographic survey. In root‐filled teeth the following parameters were assessed: the quality of the coronal restoration or crown, the lateral seal of the root filling, the length of the root filling, and the periapical status. Chi‐squared tests were used for the evaluation of differences between the groups.

Results

In group 1 there were 975 endodontically treated teeth, in group 2 there were 753. In group 1 the majority of root‐filled teeth were premolars, in group 2 the majority were molars (P < 0.001). The quality of coronal restorations (P = 0.35) and crowns (P = 0.68) did not differ significantly between the groups. In group 2 more teeth had adequately sealed root canals (P < 0.001) and adequate length of root filling (P < 0.001). More root‐filled molar teeth had apical periodontitis (AP) than root‐filled premolar and anterior teeth (P < 0.001).

Conclusions

Whilst the technical quality of endodontic treatment had improved during the last 24 years, basic differences between the populations prevented assessment of the impact of this change on disease frequencies. The study indicates that great care should be taken when comparing different patient populations, in particular more emphasis should be placed on the selection and description of study groups.
Endodontic treatment of teeth associated with a large periapical lesion
Authors: Öztan M. D.
Published: March 2003

Aim To report the healing of a large periapical lesion following non‐surgical root canal treatment.

Summary A 12‐year‐old male with a large periapical lesion around the apices of his mandibular incisors is described. The lesion formed after trauma to the mandibular anterior teeth 5 years previously. During root canal treatment, chlorhexidine gluconate was used for irrigation, and calcium hydroxide was used both for the intracanal dressing and as a base of the root canal sealer. Periapical healing was observed 3 months after obturation and continued at the 12‐month review.

Key learning points

Root canal treatment, including the use of chlorhexidine gluconate and calcium hydroxide for infection control, led to substantial healing of a large periapical lesion.

This report confirms that large periapical lesions can respond favourably to non‐surgical treatment.
A survey of methods used for post removal in specialist endodontic practice
Authors: Castrisos T. , Abbott P. V.
Published: March 2003

Aim The aims of this study were to determine the attitudes of endodontists toward the risk of root fracture when removing posts and to determine which methods they commonly used to remove posts from root‐filled teeth.

Methodology A survey was sent to all 74 members of the Australian and New Zealand Academy of Endodontists. The survey was divided into three parts to gather information concerning root canal retreatment performed in specialist endodontic practice, attitudes about the risk of root fracture when removing posts and the methods used to remove different post systems.

Results Responses were received from 62 (84%) of the Academy members. When a post was present in a tooth that required root canal retreatment, 66% of the endodontists preferred to remove the post, whilst 27% considered either post removal or periapical surgery. Forty‐five per cent reported that a root fracture had occurred during post removal, but this represented less than 0.002% of the estimated number of posts removed by all respondents. Ultrasonic vibration was the most common method used to remove posts, although post removal devices were used more often in anterior teeth; the Eggler post remover was the most commonly used device.

Conclusions Most endodontists preferred to remove posts rather than perform periapical surgery. Few root fractures were reported. Ultrasonic vibration was the most common method used to remove posts from all tooth types, with the Eggler post remover used most commonly for posts in anterior teeth.
Penetration of propylene glycol into dentine
Authors: Cruz E. V. , Kota K. , Huque J. , Iwaku M. , Hoshino E.
Published: March 2003

Cruz EV, Kota K, Huque J, Iwaku M, Hoshino E. Penetration of propylene glycol into dentine. International Endodontic Journal, 35, 330–336, 2002.

Aim This study aimed to evaluate penetration of propylene glycol into root dentine.

Methodology Safranin O in propylene glycol and in distilled water were introduced into root canals with and without artificial smear layer. Dye diffusion through dentinal tubules was determined spectrophotometrically. The time required for dye to exit through the apical foramen using propylene glycol and distilled water as vehicles was also determined. The extent and areas of dye penetration on the split surfaces of roots were assessed using Adobe Photoshop and NIH Image Software.

Results Propylene glycol allowed dye to exit faster through the apical foramen. The area and depth of dye penetration with propylene glycol was significantly greater than with distilled water (P < 0.0001). Smear layer significantly delayed the penetration of dye.

Conclusion Propylene glycol delivered dye through the root canal system rapidly and more effectively indicating its potential use in delivering intracanal medicaments.
Localized alveolar bone necrosis following the use of an arsenical paste: a case report
Authors: Özmeriç N.
Published: March 2003

Aim To describe some toxic effects of arsenic trioxide in the mouth, to condemn its continued use, and present a case in which a tooth was preserved despite significant bony destruction.

Summary A case is presented in which severe alveolar bone necrosis resulted from leakage of an arsenical devitalization paste into the periodontium.

The tooth was root canal treated before root amputation, and restored with a cuspal coverage restoration. The tooth was observed to be symptomless and functional at the one‐year follow‐up.

Key learning points

Arsenic and its compounds have no place in contemporary endodontics.

Dentists should protect their patients by avoiding the use of arsenic‐containing materials and refusing to use products whose constituents are not known.

Localized bone necrosis may not require tooth extraction. Depending on the severity of the case, the tooth may be preserved by a combination of endodontic, periodontal, prosthodontic and maintenance therapies.
Stainless steel bands in endodontics: effects on cuspal flexure and fracture resistance
Authors: Pane E. S. , Palamara J. E. A. , Messer H. H.
Published: March 2003

Aims This study investigated the effect of stainless steel bands on cuspal flexure and fracture resistance of extracted maxillary premolars.

Methodology Twenty extracted maxillary premolars (10 matched pairs) with mesio‐occluso‐distal (MOD) cavities and endodontic access were subjected to occlusal loading tests (100 N) using a servo‐hydraulic testing machine. Cuspal deflections were measured by an extensometer, with and without the band present. Ten teeth (one of each pair) then had the band removed, and all teeth were subjected to loading until fracture.

Results Mean cuspal flexure of teeth with bands was one‐half of flexure without bands (P < 0.001). Teeth with bands fractured at higher load than their matched pairs with the band removed (P < 0.001), with mean loads at fracture of 1282 N and 729 N, respectively.

Conclusions The study showed that stainless steel bands used in endodontics reduce the cuspal flexure of maxillary premolars and increase their fracture resistance.
Temporization for endodontics
Authors: Naoum H. J. , Chandler N. P.
Published: March 2003

Naoum HJ, Chandler NP. Temporization for endodontics. International Endodontic Journal, 35, 964–978, 2002.

Teeth undergoing root‐canal therapy are susceptible to microbial contamination from oral fluids both during and after treatment. With the exception of single‐visit treatment, the use of a temporary restoration is mandatory. This review aims to provide an overview of the materials and techniques used for short‐ and long‐term restorations during and immediately after endodontic treatment, and to make clinical recommendations. Further research is necessary to determine the effectiveness of temporary restorations in the conditions of the oral environment, especially with respect to leakage and functional demands.
Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 1. Intracanal drugs and substances
Authors: Hauman C. H. J. , Love R. M.
Published: March 2003

Hauman CHJ, Love RM.Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 1. Intracanal drugs and substances.International Endodontic Journal,36, 75–85, 2003.

Irrigation solutions and intracanal medicaments are used within the root canal to clean and aid in disinfecting the dentinal walls. Although these materials are intended to be contained within the root canal, they invariably contact the periapical tissues, either through inadvertent extrusion through the apex or leaching. This paper is a review on the methodology involved in biocompatibility testing followed by a discussion on biocompatibility of contemporary intracanal drugs and substances used in endodontics.
Effects of nitrogenous components of urine on sperm motility: an in vitro study
Authors: KIM  , KIM
Published: March 2003

The effects of the major nitrogenous components of urine (ammonia, creatinine, urea and uric acid) on sperm motility were investigated. Semen samples were obtained by masturbation from a young volunteer with a normal spermiogram and fertility. Sperm motility was measured using a Sperm Quality Analyzer and Makler Chamber. When semen was mixed with a urine sample for which acidity and osmolality were adjusted to pH 7.5 and 340 mOsm/kg, the higher the concentration of the urine, the poorer the sperm motility. When solutions of various concentrations of the nitrogenous compounds which are excreted in urine were mixed with semen, sperm motility decreased in proportion to ammonia levels and was markedly decreased after 30 min. However, in the case of creatinine, urea and uric acid, good motility was maintained for 30 min regardless of their amounts. In conclusion, urine ammonia content is detrimental to sperm motility and may be an important factor in retrograde ejaculation.
Chlormadinone acetate pellet implantation plus short‐term oral administration in dogs with benign prostatic hypertrophy
Authors: KAWAKAMI  , SHIMIZU  , ORIMA  , FUJITA  , HORI  , TSUTSUI
Published: March 2003

Eight beagles with benign prostatic hypertrophy (BPH) were treated by subcutaneous implantation of pellets containing 10 mg/kg chlormadinone acetate (CMA), a synthetic anti‐androgen, plus daily oral administration of CMA at 2 mg/kg per day for 7 days as a therapy for BPH. Prostatic and testicular size were measured and prostatic and testicular biopsies were performed by laparotomy before and after CMA treatment. Plasma levels of luteininzing hormone (LH), testosterone and oestradiol were also measured. The clinical signs of BPH, for example haematuria and dysuria, resolved within 1 week of treatment. Mean prostatic volume decreased to 56% of the pretreatment value. At 40 weeks after treatment, prostatic volume had decreased by 36%. Histological examination of the prostate 1 week after treatment revealed reduction in diameter of the alveoli and in height of the glandular epithelium. Degeneration and atrophy of the glands were marked 4–12 weeks after treatment. In the testis, the diameter of seminiferous tubules and the number of germ cells in the seminiferous tubules had decreased markedly at 12 and 24 weeks after treatment. Although plasma LH concentrations did not undergo any marked fluctuations after CMA treatment, levels of testosterone and oestradiol were lower than before treatment. The results indicate that implantation of 10 mg/kg CMA, plus 7‐day oral administration of 2 mg/kg CMA, bring about resolution of the clinical signs and marked reduction in prostatic volume within 1 week of treatment.
The correlates and alleged biochemical background of the resazurin reduction test in semen
Authors: ZALATA  , LAMMERTIJN  , CHRISTOPHE  , COMHAIRE
Published: March 2003

Reduction of the blue dye resazurin to pink resorufin is used to estimate the concentration of metabolically active spermatozoa in semen samples. In order to quantify the reduction of resazurin, a spectrophotometric method was developed measuring the change from blue to pink in the butanol extracted colour. The biochemical mechanisms involved in the reduction of resazurin by motile spermatozoa and seminal plasma were investigated. Addition of NADH + H+ to sperm suspension or seminal plasma increased the reduction of resazurin. The reduction reaction was inhibited by high concentrations of dicoumarol, a specific inhibitor of the diaphorase enzyme, in a dose‐dependent manner. It is suggested that the sperm diaphorase enzyme transfers electrons from NADH + H+ to resazurin, reducing it to resorufin.

The degree of resazurin reduction was strongly correlated with the concentration of motile spermatozoa recovered from the 90% Percoll fraction (r = 0.98, p < 0.001). A positive correlation was also found between the reducing capacity of seminal plasma (n = 62) on the one hand, and sperm concentration (r = 0.72, p < 0.0001), progressive motility (r = 0.45, p < 0.01), normal morphology (r = 0.50, p < 0.01), and γ‐glutamyltransferase (r = 0.36, p < 0.05) on the other hand.

These findings, together with our previous observations that the reduction reaction is inhibited by reactive oxygen species and polymorphonuclear white blood cells, increase our understanding of the biochemical basis of the resazurin test and may provide better insight into the interpretation of this test.