bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resistance‐associated point mutations of organophosphate insensitive acetylcholinesterase, in the olive fruit fly Bactrocera oleae
Authors: Vontas J. G. , Hejazi M. J. , Hawkes N. J. , Cosmidis N. , Loukas M. , Hemingway J. 
Published: March 2003

AbstractA 2.2‐kb full length cDNA containing an ORF encoding a putative acetylcholinesterase (AChE) precursor of 673 amino acid residues was obtained by a combined degenerate PCR and RACE strategy from an organophosphate‐susceptible Bactrocera oleae strain. A comparison of cDNA sequences of individual insects from susceptible and resistant strains, coupled with an enzyme inhibition assay with omethoate, indicated a novel glycine‐serine substitution (G488S), at an amino acid residue which is highly conserved across species (G396 of Torpedocalifornica AChE), as a likely cause of AChE insensitivity. This mutation was also associated with a 35–40% reduction in AChE catalytic efficiency. The I199V substitution, which confers low levels of resistance in Drosophila, was also present in B. oleae (I214V) and in combination with G488S produced up to a 16‐fold decrease in insecticide sensitivity. This is the first agricultural pest where resistance has been associated with an alteration in AChE, which arises from point mutations located within the active site gorge of the enzyme.
Specific developmental gene silencing in the honey bee using a homeobox motif
Authors: Beye M. , Härtel S. , Hagen A. , Hasselmann M. , Omholt S. W. 
Published: March 2003

AbstractManipulating the expression of genes in species that are not currently used as genetic models will provide comparative insights into the evolution of gene functions. However the experimental tools in doing so are limited in species that have not served as models for genetic studies. We have examined the effects of double stranded RNA (dsRNA) in the honey bee, an insect with considerably basic scientific interest. dsRNA derived from a 300 bp stretch of the E30 homeobox motif was injected into honey bee embryos at the anterior pole in the preblastoderm stage. We found that the dsRNA fragment successfully disrupted the protein expression of the target gene throughout the whole embryo. The disruption caused deficient phenotypes similar to known loss of function mutants of Drosophila engrailed, whereas embryos injected with nonsense dsRNA showed no abnormalities. We show that the large size of the honey bee egg (D: 0.3 mm, L: 1.6 mm) and the long preblastoderm stage (11–12 h) can be exploited to generate embryos with partial disruption of gene function, which may provide an elegant alternative to classical chimeric analyses. This is the first report of targeted disruption of gene function in the honey bee, and the results prove that the chosen target gene is a functional ortholog to engrailed in Drosophila.
CYP6B cytochrome P450 monooxygenases from Papilio canadensis and Papilio glaucus: potential contributions of sequence divergence to host plant associations
Authors: Li W. , Petersen R. A. , Schuler M. A. , Berenbaum M. R. 
Published: March 2003

AbstractTwo groups of furanocoumarin‐inducible cytochrome P450 genes, the CYP6B4 group and the CYP6B17 group, characterized in two closely related tiger swallowtails, Papilio glaucus and Papilio canadensis, are induced to different extents, with generally higher levels of CYP6B transcripts in P. glaucus. To investigate the evolutionary history of these CYP6B genes in the context of their association with furanocoumarin detoxification, we isolated thirteen CYP6B genes from these species. Each of these genes contains an intron at a conserved position (1334 nucleotides from the translation start site), which varies in length due to three insertion/deletions. The proximal 5′ end flanking sequence from the transcription initiation site is highly conserved (91–98% nt identity). The sequence 5′ to −640 is significantly variable due largely to the presence of three insertion/deletions. The sequence at the 3′ end of this region contains a putative xenobiotic response element to xanthotoxin (XRE‐xan), important for basal and xanthotoxin‐inducible transcription of the P. polyxenes CYP6B1v3 gene, and multiple elements known to regulate vertebrate phase I and II promoters, including an XRE‐AhR (Xenobiotic Response Element to Aryl hydrocarbon Receptor), an OCT‐1 element (octamer protein binding site), an ARE (Antioxidant Response Element), an EcRE (Ecdysone Response Element), and an imperfect PXR (Pregnane X Receptor) responsive element (PRE). Our analyses of CYP6B genes in these two species indicate that these genes are in an early stage of divergence and that differential exposure of these two species to chemically distinct host plants resulting from geographical isolation has had functional impacts not only on the coding regions of these genes but also on their promoter regions. Thus, changes in P450 regulation as well as catalytic activity may play a role in the evolution of host plant associations in herbivorous insects.
Characterization of JNK‐like protein derived from a mosquito cell line, C6/36
Authors: Mizutani T. , Kobayashi M. , Eshita Y. , Inanami O. , Yamamori T. , Goto A. , Ako Y. , Miyoshi H. , Miyamoto H. , Kariwa H. , Kuwabara M. , Takashima I. 
Published: March 2003

AbstractWhen Western blot analysis of heat‐killed bacteria‐ and lipopolysaccharide (LPS)‐treated Aedes albopictus mosquito cell line C6/36 was performed using antiphospholyrated c‐Jun amino‐terminal kinase (JNK) antibodies, approximately 46 kDa protein was clearly detected with a peak around 30 min. After the C6/36 cells were incubated at 45 °C in order to induce apoptosis, the 46 kDa protein continued to be detected for at least 3 h. The internalization of fluorescein‐labelled bacteria was inhibited by a JNK‐specific inhibitor SP600125, suggesting that phagocytosis involves the JNK signalling pathway in mosquito cells. Based on these results, we found one candidate for the nucleotide sequence of JNK (Ae‐JNK) from the C6/36 cells. This study is the first report regarding the mitogen‐activated protein kinase (MAPK) of mosquito.
Translation of both 5′TOP and non‐TOP host mRNAs continues into the late phase of Baculovirus infection
Authors: Van Oers M. M. , Doitsidou M. , Thomas A. A. M. , De Maagd R. A. , Vlak J. M. 
Published: March 2003

AbstractComplete cDNA sequences were obtained for ribosomal protein (rp) L15 and eukaryotic initiation factor eIF2α from the lepidopteran insect Spodoptera frugiperda, and for elongation factor eEF2 from S. exigua. The presence of a 5′ terminal oligopyrimidine (TOP) tract classified the lepidopteran rpL15 transcript as a TOP mRNA. For eEF2, two types of transcripts were observed, one of which had a 5′TOP tract. The transcript levels for rpL15, eEF2 and eIF2α decreased following baculovirus infection. Polysome analysis showed that the corresponding mRNAs remained to be translated until at least 16 h post‐infection for both TOP and non‐TOP mRNAs. Baculovirus‐induced host shut‐off therefore appears to be regulated at the level of RNA abundance rather than at the translational level.
Cyclic fatigue of Profile rotary instruments after simulated clinical use
Authors: Yared G. M. , Dagher F. E. Bou , Machtou P. 
Published: March 2003

Aim The purpose of this study was to evaluate cyclic fatigue of Profile Ni–Ti rotary instruments (PRIs) after dry heat sterilization and up to 10 times simulated clinical use.Methodology Instruments of size 40–15 were used in a crown‐down technique. Three groups were included in this study. In groups 1 and 2, each set of instruments was used in five and 10 canals, respectively. Group 3 was the control group. NaOCl at a concentration of 2.5% was used as an irrigant. Each set of instruments was sterilized before each use.Results The PRI size 40 demonstrated the lowest incidence of rotations to breakage. One‐way analysis of variance and Tukey’s HSD test showed statistically significant differences among different file sizes within each group.Conclusions The results showed that dry heat sterilization and simulated clinical use in the presence of NaOCl did not lead to a decrease in the number of rotations to breakage of the files.
Adaptation and sealability of two contemporary obturation techniques in the absence of the dentinal smear layer
Authors: Kytridou V. , Gutmann J. L. , Nunn M. H. 
Published: March 2003

Kytridou V, Gutmann JL, Nunn MH. Adaptation and sealability of two contemporary obturation techniques in the absence of the dentinal smear layer. International Endodontic Journal, 32, 464–474 1999.Aim The aim of this study was to evaluate the adaptation and short‐ and long‐term sealability of two different thermoplastic techniques — a core carrier technique, Thermafil; and a warm vertical continuous wave of compaction technique, System B.Methodology Fifty‐one mesial roots of mandibular molars with separate canals, patent canal orifices and curvature greater than 15 degrees were cleaned and shaped with Orifice Shapers and ProFile.04/.06 taper Ni‐Ti rotary files using 5.25% NaOCl and 17% REDTA to a size 30.04 taper Profile at the apex to create a continuous tapered preparation. Canals were randomly obturated with Sealapex root canal sealer and either alpha‐phase gutta‐percha on a plastic Thermafil carrier, or nonstandardized beta‐phase gutta‐percha using the System B heat source. Proximal radiographs of roots were evaluated by three examiners based on established criteria for overall material adaptation, apical adaptation and filling material extrusion. Teeth were randomly separated into three groups of 17 each and placed in black India ink for 10 days, 24 h, or after 67 days storage in Hank’s Balanced Salt Solution. All roots were demineralized and rendered transparent. Three examiners evaluated the apical leakage by the linear measurement of dye penetration under the stereo‐microscope. The movement of filling material into canal irregularities was also evaluated.Results Both obturation techniques were not significantly different in the overall canal obturation and in the apical third adaptation (P 0.05). Significantly more filling material extrusion beyond the apex was noted with the Thermafil technique (P 0.001). No significant difference was found amongst the 67‐day, 10‐day and 24h System B groups (P 0.05). The 67‐day Thermafil group showed significantly more leakage than the 10‐day and 24h Thermafil groups. There was a significant difference in the degree of leakage between the 67‐day Thermafil group and the 67‐day System B group (P 0.05), but not between the 10‐day and 24 h groups (P 0.05). Both obturation techniques produced substantial filling material movement into canal irregularities.Conclusions It was concluded that Thermafil demonstrated more filling material extrusion beyond the apex and significantly more long‐term apical leakage.
Shaping ability of .04 and .06 taper ProFile rotary nickel–titanium instruments in simulated root canals
Authors: Bryant S. T. , Dummer P. M. H. , Pitoni C. , Bourba M. , Moghal S. 
Published: March 2003

Aim The aim of this study was to determine the shaping ability of ProFile .04 and .06 taper rotary nickel–titanium instruments in simulated canals.Methodology A total of 40 simulated root canals made up of four different shapes in terms of angle and position of curvature were prepared using the ‘crown‐down’ approach recommended by the manufacturer. Pre‐operative pictures of each canal were recorded on optical discs using an image analysis package. The simulated canals were prepared and postoperative pictures superimposed on the original images.Results No instrument fractures occurred and none deformed; none of the canals became blocked with debris. Change in working distance was, on average, 0.063 mm with 33 canals retaining the correct length. Overall, five zips (12.5%) were created and 24 (60%) canals demonstrated a widened area on the outer aspect of the canal between the end‐point and the curve. Two danger zones (5%) were created and two perforations but no ledges were found. Between canalshapes there were highly significant differences (P 0.0001) for the incidence of zips and elbows but not for the other aberrations. There were highly significant differences (P 0.0001) for the total width of the canals between the various canal shapes at the apex of the curve, the beginning of the curve and half way to the orifice, and a significant difference (P 0.05) at the end‐point. There were highly significant differences (P 0.0001) for the amount of resin removed from the outer aspect of the curve at the end‐point and at the beginning of the curve, and significant differences (P 0.05) at the apex of the curve and half way to the orifice. There were highly significant differences (P 0.0001) for the amount of resin removed from the inner aspect of the curve at the beginning of the curve and half way to the orifice. Overall, transportation was towards the outer aspect of the canal except at the beginning of the curve.Conclusions Under the conditions of this study the combined use of .04 and .06 taper ProFile instruments was rapid, effective and produced good canal shapes except in those specimens with short curves that began near the end‐point.
Analysis of the healing response to gutta‐percha and Diaket when used as root‐end filling materials in periradicular surgery
Authors: Witherspoon D. E. , Gutmann J. L. 
Published: March 2003

Witherspoon DE, Gutmann JL. Analysis of the healing response to gutta‐percha and Diaket when used as root‐end filling materials in periradicular surgery. International Endodontic Journal, 33, 37–45, 2000.Aim  To analyse the healing response to gutta‐percha and Diaket when used as root‐end filling materials in periradicular surgery.Methodology Periradicular surgery was completed using the mandibular second, third and fourth premolar teeth from nine male mongrel dogs. The six roots on one side of the mouth were randomly allocated to one of the following groups: group A: a resected root end and a burnished gutta‐percha root filling; group B: cavities were prepared to a depth of 4.0 mm, using ultrasonic root‐end preparation and filled with Diaket. The response was evaluated histologically at 55 (nine specimens) and 150 (three specimens) days post operatively.Results  The data for the 55‐day period was analysed statistically using Wilcoxon's Signed Ranks test. No statistical analysis was carried out on the 150‐day group due to the small number of specimens. The level of significance was set at P <0.05. No statistical significance was observed in the healing response between Diaket and gutta‐percha in the following categories at 55 days: inflammatory response, angiogenesis, root‐end resorption, and cementum deposition. Statistically significant differences were observed in the healing categories: bone apposition (P <0.05) and periodontal ligament formation (P <0.05).Conclusions  At both time intervals, Diaket had a better healing response that was characterized by hard tissue formation adjacent to the root‐end filling material bordered by occasional multinucleated giant cells. The nature of both the hard tissue formation and the adjacent cells, however, remains undetermined. Diaket displayed the best healing of either material used in this study.
The effects of Ledermix paste on discolouration of immature teeth
Authors: Kim S. T. , Abbott P. V. , McGinley P. 
Published: March 2003

AbstractAimThe aims of this study were to: (i) investigate the effects of Ledermix paste as an intracanal medicament on discolouration of immature teeth, (ii) examine whether the discolouring effects were related to the method of application, (iii) examine the effects of sunlight upon discolouration of immature teeth and (iv) compare the degree of discolouration between mature and immature teeth.MethodologyThe root canals of 45 immature extracted human teeth were prepared and filled with either Ledermix paste, calcium hydroxide [Ca(OH)2], or saline. In group 1, Ledermix paste was only placed apical to the cemento‐enamel junction (CEJ) whilst in groups 2 and 3, the paste filled the entire pulp chamber and the root canals. In group 4, Ca(OH)2 paste and in group 5, saline (control) were allowed to fill the pulp chamber and the root canals. Group 3 teeth were kept in the dark and the other groups were exposed to daylight for 12 weeks.ResultsAfter 12 weeks, sunlight exposure had caused dark grey‐brown staining in the Ledermix groups but this did not occur when the teeth were kept in the dark. More severe staining was noted when Ledermix paste filled the pulp chamber than when the paste was restricted to below the CEJ and when teeth were exposed to sunlight. When compared to the results of a similar study using mature teeth, the results were similar but the immature teeth were more severely stained than the mature teeth. The Ca(OH)2 paste caused an increase in lightness and yellowness in immature teeth.ConclusionIt was concluded that Ledermix paste may cause discolouration of immature teeth. Such effects can be minimized if placement of the paste is restricted to below the gingival margin. Clinicians should ensure that Ledermix paste is not left on the walls of access cavities, especially in immature teeth.
Lasers in endodontics: a review
Authors: Kimura Y. , Wilder‐Smith P. , Matsumoto K. 
Published: March 2003

AbstractSince the development of the ruby laser by Maiman in 1960 and the application of the laser for endodontics by Weichman in 1971, a variety of papers on potential applications for lasers in endodontics have been published. The purpose of this paper is to summarize laser applications in endodontics, including their use in pulp diagnosis, dentinal hypersensitivity, pulp capping and pulpotomy, sterilization of root canals, root canal shaping and obturation and apicectomy. The effects of laser on root canal walls and periodontal tissues are also reviewed. The essential question is whether a laser can provide equal or improved treatment over conventional care. Secondary issues include treatment duration and cost/benefit ratio. This article reviews the role of lasers in endodontics since the early 1970s, summarizes many research reports from the last decade, and surmises what the future may hold for lasers in endodontics. With the potential availability of many new laser wavelengths and modes, much interest is developing in this promising field.
Radiographic evaluation of periapical healing after obturation of infected root canals: an in vivo study
Authors: Katebzadeh N. , Sigurdsson A. , Trope M. 
Published: March 2003

Katebzadeh N, Sigurdsson A, Trope M. Radiographic evaluation of periapical healing after obturation of infected root canals: an in vivo study. International Endodontic Journal, 33, 60–65, 2000.Aim  To radiographically compare periapical repair of roots with infected root canals obturated in one‐step or with calcium hydroxide (Ca(OH)2) intracanal medication in two steps.Methodology Standardized preoperative periapical radiographs were taken of 72 roots of vital dogs' teeth. All roots were then aseptically instrumented to ISO size 45. As negative controls, 12 roots were aseptically obturated. The remaining roots were infected with dental plaque and closed. Six weeks later, apical periodontitis was radiographically confirmed in the infected roots. The roots were divided into the following groups: group 1, one‐step (n=24); roots were irrigated with 10 cc saline, obturated, and permanently restored. Group 2, Ca(OH)2 (n=24); roots were treated as in group 1, except that after saline irrigation Ca(OH)2 medicament was placed in the canal 1 week before obturation. Group 3, positive control (n=12); theroots were irrigated with saline, access permanently closed but canals not obturated. Group 4, negative control (n=12); previously aseptically obturated roots were permanently restored. After 6 months, standardized postoperative radiographs were obtained. Three independent evaluators blinded to the treatment groups evaluated the preoperative and postoperative radiographs. The evaluators were instructed to rate each root, based on changes on the radiographs, as failed, improved or healed.Results  Radiographically, the percentage of cases that completely healed were similar for the one‐step and Ca(OH)2 groups (35.3% vs. 36.8%). However, the Ca(OH)2 group had fewer failed cases (15.8% vs. 41.2%) and more improved cases (47.4% vs. 23.5%) than the one‐step group.Conclusion  Power statistics demonstrated that at 43 cases per group, Ca(OH)2 treatment would be statistically superior to one‐step treatment. We consider this number to be clinically important.
Apparent periapical repair without operative intervention: a case report and discussion
Authors: Whitworth J. M. 
Published: March 2003

AbstractCase reportA case is described where substantial reduction of an established periapical lesion appeared to take place in the absence of operative intervention, and as the crown of the tooth was progressively destroyed by dental caries. The case raises debate on the pathogenesis, diagnosis and monitoring of endodontic lesions, and may stimulate renewed research interest in these most fundamental elements of clinical endodontology.
A comparison of the relative efficacies of four hand and rotary instrumentation techniques during endodontic retreatment
Authors: Imura N. , Kato A. S. , Hata G.‐I. , Uemura M. , Toda T. , Weine F. 
Published: March 2003

AbstractAimThe purpose of this study was to quantify the amount of remaining gutta‐percha/sealer on the walls of root canals when two engine‐driven instruments (Quantec and ProFile) and two hand instruments (K‐file and Hedström file) were used to remove these materials. The amount of apically extruded debris and the time required for treatment were also recorded.MethodologyOne hundred extracted mandibular premolars were prepared using a modified step‐back, flare technique and obturated with the lateral condensation technique. After repreparation with the test instruments, the specimens were cut transversally at the cervical, middle and apical thirds with steel discs and the three sections were split longitudinally. The amount of residual debris on the canal walls in each section was examined using a stereomicroscope.ResultsIn all groups the cervical and middle thirds showed no debris. In the apical third, obturating material was observed in some specimens. No statistically significant difference was found between the two groups for incidence of debris, although the Hedström group showed a greater number of samples with remaining gutta‐percha/sealer. When analysing dirty specimens only, there was a statistically significant difference between the four groups (P < 0.01) with the Hedström group having significantly less length of canal wall with remaining obturation material than the Quantec group. There was no significant difference amongst the groups for weight of extruded debris. However, there was a significant difference amongst the groups for mean treatment time with the Hedström file group requiring significantly less time than the Quantec group (P < 0.001); no significant differences were found between the other groups. Six instruments fractured in the Quantec group, four in the ProFile group, two in the Hedström group and two in the K‐type group.ConclusionsThe results showed that overall, all instruments may leave filling material inside the root canal. During retreatment there is a risk of instrument breakage, especially rotary instruments.