bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of a ribosomal DNA intergenic spacer region from the yellow fever mosquito, Aedes aegypti
Authors: Wu C. C. N. , Fallon A. M.
Published: March 2003

We have sequenced the 1.8 kb intergenic spacer (IGS) region from an Aedes aegypti ribosomal DNA repeat and have identified conserved functional motifs shared with the related mosquito, Aedes albopictus. Despite the shorter length and greater homogeneity of the Ae. aegypti IGS region, the sequences of two potential RNA polymerase I core promoters and closely associated terminator elements were highly conserved. Primer extension analysis indicated that the predominant transcription initiation site in the Ae. aegypti rDNA repeat unit region lay at or near the A residue at nucleotide position 1003 in the ‘upstream’ RNA polymerase I promoter. This observation was supported by the higher sequence identity between the upstream promoters in Ae. aegypti and Ae. albopictus, relative to the downstream promoters. In contrast to strong similarities among proximal regulatory elements, the Ae. aegypti IGS sequence upstream of the transcription initiation site lacked the ordered array of contiguous ∼200 nucleotide subrepeats previously found in the IGS of Ae. albopictus. In Ae. aegypti, only 4∼50 nucleotide R subrepeats separated by unique sequences, followed by 2∼50 nucleotide E subrepeats, occurred upstream of the transcription initiation site. Despite their differences in size and sequence, however, the four Ae. aegypti R subrepeats shared an internal structural organization that included a conserved core with ‘spacer’ promoters and recombinogenic elements similar to those in the longer Ae. albopictus subrepeats. These observations provide an important basis for further characterization of transcription specificity among mosquito RNA polymerase I promoters and associated regulatory elements, and contribute towards the eventual use of these elements in transgenic applications.
DEC: a new miniature inverted‐repeat transposable element from the genome of the beetle Tenebrio molitor
Authors: Braquart C. , Royer V. , Bouhin H.
Published: March 2003

In this paper we describe a novel family of miniature inverted‐repeat transposable elements (MITEs), named DEC, isolated from the genome of the beetle Tenebrio molitor. These elements are highly reiterated and their number is estimated to be around 3500 per haploid genome. Two of them have been isolated and the two sequences are 84% identical. Like other MITEs, they are characterized by their small size, their A + T richness, the presence of terminal inverted repeats and the absence of open reading frames. These data suggest that MITEs are probably widely distributed in arthropods.
Phylogenetic status of a fecundity‐enhancing Wolbachia that does not induce thelytoky in Trichogramma
Authors: Vavre F. , Girin C. , Boulétreau M.
Published: March 2003

Wolbachia are widespread bacteria which infect a number of species of insects and other arthropods. They manipulate the reproduction of their hosts at their own advantage. In Trichogramma species all Wolbachia known so far induce thelytoky and form a monophyletic group in the B subdivision of Wolbachia. Here we show that some strains of the arrhenotokous species Trichogramma bourarachae harbour Wolbachia symbionts that locate in the A subdivision, and which do not induce thelytoky. Although the symbiont of T. bourarachae is closely related to Wolbachia that induce cytoplasmic incompatibility in other insects, no cytoplasmic incompatibilities were found in crosses involving infected and uninfected strains. In T. bourarachae the presence of this Wolbachia is associated with a higher fecundity of strains. Our results strongly suggest that Wolbachia are involved in this increased fecundity. Theoretical models on the evolution of host‐Wolbachia interaction predict that a reduced effect on reproduction can be selected for if cost of infection is reduced. The effect in T. bourarachae should illustrate this prediction.
DNA sequence analysis of the ribosomal DNA ITS2 region for the Anopheles punctulatus group of mosquitoes
Authors: Beebe N. W. , Ellis J. T. , Cooper R. D. , Saul A.
Published: March 2003

The internal transcribed spacer 2 (ITS2) from the ribosomal DNA was sequenced and characterized for ten cryptic species in the Anopheles punctulatus group, the members of which are major vectors of malaria and filariasis in the south‐west Pacific. The length of the ITS2 ranged from 549 bp to 565 bp and displayed levels of sequence variation ranging from 2.3% to 24.3% due mainly to indels of simple sequences. The GC content varied from 61.3% to 70.9%. These values were higher than those found in other cryptic species of mosquitoes and comparable only to members of the An. dirus complex suggesting a possible link between this group of Asian mosquitoes and the An. punctulatus group. Optimal and suboptimal secondary structures were investigated and revealed structures where the 5′ region folded independently of the 3′ region. Due to the large level of sequence variation between species, the ITS2 region proved unsuitable for phylogenetic analysis.
The excision of polydnavirus sequences from the genome of the wasp Cotesia congregata (Braconidae, Microgastrinae) is developmentally regulated but not strictly restricted to the ovaries in the adult
Authors: Savary S. , Drezen J.‐M. , Tan F. , Beckage N.E. , Periquet G.
Published: March 2003

Cotesia congregata polydnavirus (CcPDV) is essential for the successful parasitism of Manduca sexta larvae by the braconid wasp Cotesia congregata. In the absence of PDV, parasitoid eggs are encapsulated. Molecular analysis has demonstrated that polydnavirus sequences are integrated in the wasp chromosomes, and an ultrastructural analysis has shown that PDV replication occurs in the calyx region in the ovaries of the wasp. The bracovirus sequences appear to be excised from the wasp genome in the calyx cells where the virus replicates. Following excision of the virus sequences, the flanking sequences are rejoined. We analysed the production of two polydnavirus circles during wasp development and in different body parts of the adults of both sexes. Our study indicates that the excision of viral sequences is developmentally regulated, beginning in the pupal stage. In the adult wasp, excision occurs ubiquitously. However, regulation in the adult seems to occur only in diploid individuals, as no excision is detected in haploid males produced from virgin females.
Microsatellite frequency and size variation in the parthenogenetic parasitic waspVenturia canescens(Gravenhorst) (Hymenoptera: Ichneumonidae)
Authors: Butcher R. D. J. , Hubbard S. F. , Whitfield W. G. F.
Published: March 2003

Nine genomic libraries of the parthenogenetic waspVenturia canescenswere screened for microsatellite loci. In contrast to other Hymenoptera (GT)nand not (CT)n, was the predominant repeat category found with 14 kb and 28 kb genomic DNA between loci, respectively. Mono‐ and trinucleotide microsatellites were rarer, occurring at frequencies between 231 kb and 589 kb of genome, whilst tetranucleotide repeats are scarce, with (ATTC)nand (CCGG)nloci occurring every 692 kb and 983 kb, respectively, and only one small imperfect (GATA)nlocus and no (GACA)nloci were revealed. Over 70% of the dinucleotide, and all the trinucleotide microsatellites were small (less than eleven repeats), whilst 60% to 80% of loci were imperfect. Moreover, very few compound microsatellites and only a single association between different microsatellites were observed.
The kdr mutation occurs in the Mopti form of Anopheles gambiaes.s. through introgression
Authors: Weill M. , Chandre F. , Brengues C. , Manguin S. , Akogbeto M. , Pasteur N. , Guillet P. , Raymond M.
Published: March 2003

Anopheles gambiae
s.s. is a complex of sibling taxa characterized by various paracentric inversions. In west and central Africa, where several taxa are sympatric, a kdr mutation responsible for pyrethroid resistance has been described in only one (the S taxon), suggesting an absence of gene flow between them. Following a thorough sampling, we have found a kdr mutation in another taxon (M). To establish whether this mutation is the same event or not, the large intron upstream of the kdr mutation was sequenced to find polymorphic sites in susceptible/resistant and M/S mosquitoes. The low genetic diversity found in this DNA region indicates that a local genetic sweep has recently occurred. However, some polymorphic sites were found, and it is therefore concluded that the kdr mutation in the M taxon is not an independent mutation event, and is best explained by an introgression from the S taxon. These results are discussed within the context of possible gene flow between members of An. gambiae s.s. taxa, and with the possible spread of the kdr mutation in other closely related malaria vectors of the An. gambiae complex.
Psyllid endosymbionts exhibit patterns of co‐speciation with hosts and destabilizing substitutions in ribosomal RNA
Authors: Spaulding Allen W. , von Dohlen Carol D.
Published: March 2003

Eubacterial 16S rDNAs were sequenced from endosymbionts of seven psyllids (Psylloidea) and one whitefly (Aleyrodoidea), to investigate the evolution of endosymbionts and their hosts. Primary endosymbionts from all psyllids formed a highly supported clade, tentatively placed as the sister to whitefly primary endosymbionts, and showing several points of congruence with the host morphological phylogeny. Almost all host taxa yielded an additional eubacterial sequence, related either to known psyllid secondary endosymbionts or to other insect endosymbionts or parasites. The relationships of some secondary endosymbionts also suggested cospeciation with psyllid hosts, or ancient horizontal transfers. All primary endosymbionts, and some secondary endosymbionts, exhibited molecular genetic effects of a long‐term, intracellular existence in their biased nucleotide content and decreased stability of rRNA secondary structure.
Molecular evidence of incipient speciation within Anopheles gambiae s.s. in West Africa
Authors: Torre A. della , Fanello C. , Akogbeto M. , Dossou‐yovo J. , Favia G. , Petrarca V. , Coluzzi M.
Published: March 2003

We karyotyped and identified by polymerase chain reaction restriction fragment length polymorphism (PCR‐RFLP) analysis Anopheles gambiae s.s. samples collected in several African countries. The data show the existence of two non‐panmictic molecular forms, named S and M, whose distribution extended from forest to savannahs. Mosquitoes of the S and M forms are homosequential standard for chromosome‐2 inversions in forest areas. In dry savannahs, S is characterized mainly by inversion polymorphisms typical of Savanna and Bamako chromosomal forms, while M shows chromosome‐2 arrangements typical of Mopti and/or Savanna and/or Bissau, depending on its geographical origin. Chromosome‐2 inversions therefore seem to be involved in ecotypic adaptation rather than in mate‐recognition systems. Strong support for the reproductive isolation of S and M in Ivory Coast comes from the observation that the kdr allele is found at high frequencies in S specimens and not at all in chromosomal identical M specimens. However, the kdr allele does not segregate with molecular forms in Benin.
Phylogeny of raspberry beetles and other Byturidae (Coleoptera)
Authors: Malloch G. , Fenton B. , Goodrich M. A.
Published: March 2003

Nuclear ribosomal ITS2 and mitochondrial cytochrome oxidase DNA sequences were analysed from the Byturidae (Coleoptera), which includes the raspberry beetles. The secondary structure of ITS2 was plotted and interspecific changes analysed. Evidence for selection on simple sequence repeats within the ITS2 was found. Phylogenetic trees based on the mitochondrial and ribosomal sequences were compared. They were in parity, indicating they reflect the true evolutionary histories of these insects. There was no evidence for hybridization in the populations surveyed, but there was evidence that the American raspberry beetle, Byturus unicolor, is divided into at least three distinct groupings. Despite sharing a related host, the raspberry pests from America were not the most related to the European raspberry beetle. Instead, links between Byturus affinis from Japan and the American raspberry beetle suggest that this lineage originated in Asia and colonized the Western USA.
Intragenomic variation in ITS2 rDNA in the louse of humans, Pediculus humanus: ITS2 is not a suitable marker for population studies in this species
Authors: Leo N. P. , Barker S. C.
Published: March 2003

The two internal transcribed spacers (ITS) of ribosomal DNA are often used as markers of populations of insects. We studied the ITS2 of the head lice and body lice of humans, to determine whether this gene is a suitable marker of populations of these insects. ITS2 sequences were amplified by PCR from lice from four different countries: Australia, China, Japan and the USA. Direct cycle‐sequencing of some of these PCR products gave equivocal nucleotide chromatograms. This indicated that some lice had more than one ITS2 sequence, so we cloned PCR products from these lice. Temperature gradient gel electrophoresis (TGGE) revealed that 50 of the 67 clones we screened had different nucleotide sequences. All lice had several ITS2 types, including those with unequivocal chromatograms. A phylogenetic tree of 15 different ITS2 sequences showed that the sequences from individual lice were not monophyletic. We conclude that the ITS2 is not a useful marker of populations for Pediculus humanus.
Functional analysis of a G protein‐coupled receptor from the Southern cattle tick Boophilus microplus (Acari: Ixodidae) identifies it as the first arthropod myokinin receptor
Authors: Holmes S. P. , Barhoumi R. , Nachman R. J. , Pietrantonio P. V.
Published: March 2003

The myokinins are invertebrate neuropeptides with myotropic and diuretic activity. The lymnokinin receptor from the snail Lymnaea stagnalis (Mollusca) has been the only previously identified myokinin receptor. We had cloned a G protein‐coupled receptor (AF228521) from the tick Boophilus microplus (Arthropoda: Acari), 40% identical to the lymnokinin receptor, that we have now expressed in CHO‐K1 cells. Myokinins at nanomolar concentrations induced intracellular calcium release, as measured by fluorescent cytometry and the receptor coupled to a pertussis toxin‐insensitive G protein. Absence of extracellular calcium did not inhibit the fluorescence response, indicating that intracellular stores were sufficient for the initial response. Control cells only transfected with vector did not respond. We conclude that the tick receptor is the first myokinin receptor to be cloned from an arthropod.
Influence of file handle attachments on tactile discrimination: an evaluation by dental students
Authors: Warren  , Chandler
Published: March 2003

This study used a simulator to determine the effectiveness of two file‐handle sleeves that are claimed to improve tactile discrimination and the ease of manipulation of endodontic hand instruments. Thirty final‐year dental undergraduates inserted files into instrument setting rods until a putty resistance was felt, following which depth of penetration into the material was measured with a microscope. Results were analysed statistically. Despite favourable comments from participants in the trial, the devices failed to deliver enhanced tactile discrimination.
Shaping ability of Quantec Series 2000 rotary nickel‐titanium instruments in simulated root canals: Part 1
Authors: Thompson  , Dummer
Published: March 2003

The aim of this study was to determine the shaping ability of Quantec Series 2000 nickel‐titanium instruments in simulated canals. A total of 40 simulated root canals made up of four different shapes in terms of angle and position of curvature were prepared by Quantec instruments using the technique recommended by the manufacturer. Part 1 of this two‐part report describes the efficacy of the instruments in terms of preparation time, instrument failure, canal blockages, change in canal length and three‐dimensional canal form. The time necessary for canal preparation was on average 5.7 min and was significantly influenced (P < 0.01) by canal shape. One instrument fractured and three size nine instruments deformed; however, canal shape did not influence significantly instrument failure. All of the canals remained patent, none became blocked with debris. The majority of the canals maintained working distance (26 out of 40), however the mean change in length differed significantly (P < 0.05) between canal types. Overall, canals with 40° curves lost length whilst those with 20° curves gained in length. Examination of intracanal impressions revealed that preparation with Quantec Series 2000 instruments produced canals with definite apical stops, smooth canal walls and good flow and taper. However, the quality of apical smoothness and flow was influenced significantly (P < 0.0001) by canal shape with specimens having 40° canals displaying less desirable qualities. Under the conditions of this study, Quantec Series 2000 rotary nickel‐titanium instruments prepared simulated canals rapidly, safely and with good three‐dimensional form.
Location of contact areas on rotary Profile1 instruments in relationship to the forces developed during mechanical preparation on extracted teeth
Authors: Blum J. ‐Y. , Machtou P. , Micallef J. ‐P.
Published: March 2003

Aim The aim of this study was to locate the areas of direct instrument contact with dentine in the root canal system during rotary preparation and to analyse the relationship between these areas and the vertical forces and torque developed during the preparation.

Methodology Canal preparations were performed by endodontists either with the step‐back (SB) or the crown‐down (CD) technique. In order to locate the areas of contact, the instruments were coated with two layers of gold by electro‐deposition. They were photographed before and after use, and a coding system, based on mm from the instrument tip, was devised to designate areas of gold removal or instrument wear due to friction. To standarise the conditions of instrument manipulation, the teeth were fixed in the Endographe holder, and this device was used to measure vertical forces and torque.

Results The results showed that the first series of instruments used for the CD technique (taper 0.06) left 2 ± 1 mm of the tip with the gold intact, indicating that these instruments and this step of the CD technique are the safest part of the preparation. For all other instruments (taper 0.04 series), the areas of gold removal involved the 3 mm around the tip and this finding was independent of the order of instrument use and preparation technique (SB or CD). The differences between the two techniques were significant in terms of the mean area of decolouration and the mean force and torque values. For the SB and CD techniques, the contact areas were, respectively, 10 ± 3 and 7 ± 2 mm. The forces and torque values were correspondingly higher for SB vs. CD: the mean values were, respectively, 19 and 21 N for vertical forces and 16 105 and 13 105 Nm for torque.

Conclusions The recorded torque values and the location on the instruments of the areas of contact with dentine during this development of torque ie at or near the tip, indicate that great caution should be used with the rotary technique, particularly with the taper 0.04 instruments, regardless of preparation technique.
Prevalence of vertical root fractures in extracted endodontically treated teeth
Authors: Fuss Z. , Lustig J. , Tamse A.
Published: March 2003

Aim The aim of this study was to evaluate the prevalence of vertical root fractures (VRF) in extracted endodontically treated teeth and to correlate the findings to previous studies and surveys.

Methodology Root‐canal‐treated teeth were referred for extraction from a public dental clinic. The endodontic therapy had been completed by a variety of dentists. Each tooth was evaluated following extraction by the oral surgeon who performed the procedure; theexact aetiology for the clinical diagnosis that led to the extraction was recorded.

Results The major reasons for extraction were restorative (43.5%) and endodontic (21.1%), followed by vertical root fractures (10.9%).

Conclusions The relatively high prevalence of vertical root fractures in this survey compared with previous clinical and radiographic surveys was probably related to the difficulties in making a clinical diagnosis of vertical fractures before extraction.
Deposition of calcified tissue around an overextended gutta‐percha cone: case report
Authors: Khabbaz M. G. , Papadopoulos P. D.
Published: March 2003

Case report Root canal treatment was performed in a mandibular right second premolar with a periapical lesion and apical resorption. The root canal was prepared with K‐files using the step‐back technique and 3% NaOCl as an irrigant; during obturation gross overfilling of gutta‐percha occurred. The tooth was permanently restored with a post and core along with a crown. Although healing of the periapical lesionoccurred and the patient reported that he was symptom‐free, the tooth was extracted after 4 years because of a subgingival root fracture. Following extraction the tooth was examined with SEM. The examination revealed the presence of newly formed calcified tissue at resorption sites on the root apex. This newly formed tissue extended from the surface of the root around the apex to the extruded gutta‐percha cone to which it was well adapted, forming a bridge between the cone and the root.
Comparison of two vertical condensation obturation techniques: Touch ’n Heat modified and System B
Authors: Silver G. K. , Love R. M. , Purton D. G.
Published: March 2003

Aim The aims of this study were firstly to compare the area of canal occupied by gutta‐percha, sealer or voids using the System B heating device with that obtained by a modified vertical condensation technique using the Touch ’n Heat; and secondly to compare the temperature changes at the root canal wall and external root surface during obturation with the above techniques.

Methodology Forty‐five resin blocks, each with a standardized, simulated, prepared main root canal and five lateral canals, were assigned to three equal experimental groups. The canals were obturated using either the System B technique at two different temperature settings, or vertical condensation with a Touch ’n Heat instrument as the heat source. A heat transfer model was used to simultaneously record internal and external root surface temperature elevations duringobturation by the three techniques. Data were analysed using unpaired Student's t‐test and Mann–Whitney U‐test.

Results Both obturation techniques produced root fillings consisting of over 90% gutta‐percha at most levels, although the percentages of sealer and voids 2–3 mm from the working length following System B obturation were higher than those found following modified vertical condensation. Modified vertical condensation resulted in more gutta‐percha in lateral canals. Obturation was accomplished more quickly using the System B, and temperature elevations produced during obturation with the System B were significantly less (P 0.001) than with vertical condensation. An elevation of external root surface temperature by more than 108C occurred during vertical condensation.

Conclusions The results suggest that the System B may produce an acceptable obturation and that the use of a Touch ’n Heat source during vertical condensation may result in damage to the periodontium.
CD57+ cells in radicular cyst
Authors: Moreira P. R. , Santos D. F. M. , Martins R. D. , Gomez R. S.
Published: March 2003

Aim  As CD57 antigen is an important modulator of the immune system, the purpose of the present study was to compare the expression of this antigen on radicular cysts (RC) with hyperplastic or atrophic epithelium.

Methodology Twenty cases of RC were retrieved and classified as atrophic or hyperplastic. A biotin‐streptavidin amplified system was used for identification of the CD57 receptor.

Results  The results demonstrated a greater percentage of CD57+ cells in RC with atrophic epithelium compared to hyperplastic epithelium.

Conclusion  As the expression of CD57 is indicative of immunosuppression, it may constitute a negative immunomodulator of RC's epithelium growth. Further studies are necessary to understand the importance of this cell to the biological activity or inactivity of RC's epithelium development.
Inactivation of local root canal medicaments by dentine: an in vitro study
Authors: Haapasalo H. K. , Sirén E. K. , Waltimo T. M. T. , Òrstavik D. , Haapasalo M. P. P.
Published: March 2003

Aims  The aim of the study was to investigate the inactivation by dentine of the antibacterial activity of various commonly used local root canal medicaments.

Methodology The medicaments tested were saturated calcium hydroxide solution, 1% sodium hypochlorite, 0.5% and 0.05% chlorhexidine acetate, and 2/4% and 0.2/0.4% iodine potassium iodide. Dentine was sterilized by autoclaving and crushed into powder with a particle size of 0.2–20μm. Aliquots of dentine suspension were incubated with the medicaments in sealed test tubes at 378C for 24 h or 1 h before adding the bacteria. In some experiments bacteria were added simultaneously with dentine powder and the medicament. Enterococcus faecalis A197A was used as a test organism. Samples for bacterial culturing were taken from the suspensions at 5 min, 1 h and 24 h after adding the bacteria.

Results  Dentine powder had an inhibitory effect on all medicaments tested. The effect was dependent on the concentration of the medicament as well as on the length of the time the medicament was preincubated with dentine powder before adding the bacteria. The effect of calcium hydroxide on E. faecalis was totally abolished by the presence of dentine powder. Similarly, 0.2/0.4% iodine potassium iodide lost its effect after preincubation for 1 h with dentine before adding the bacteria. The effect of 0.05% chlorhexidine and 1% sodium hypochlorite on E. faecalis was reduced but not totally eliminated by the presence of dentine. No inhibition could be measured when full strength solutions of chlorhexidine and iodine potassium iodide were used in killing E. faecalis.

Conclusions  The dentine powder model appears to be an efficient tool for the study of interactions between local endodontic medicaments, dentine, and microbes.
Expression of β1 integrins in human dental pulp in vivo: a comparative immunohistochemical study on healthy and chronic marginal periodontitis samples
Authors: Taşman F. , Ataç A. , Er N. , Dağdeviren A. , Kendir B.
Published: March 2003

Aim

The objective of this study was to determine the tissue distribution of β1 integrin chains in sound human dental pulps and to compare the findings with connective tissue compartments of other organs and to pulp tissue in teeth extracted due to periodontal disease.

Methodology

Freshly frozen pulp tissue samples from teeth extracted for orthodontic reasons were examined and compared to samples from teeth extracted due to chronic (marginal) periodontitis. β1 integrin chains were determined using an indirect‐immunoperoxidase technique. Seven monoclonal antibodies recognizing α1, α2, α3, α4, α5, α6 and β1 chains of Very Late Activation Antigen (VLA) integrins were used for this purpose.

Results

VLA‐1, VLA‐2, VLA‐3 and VLA‐5 were expressed by vascular endothelium and vascular smooth muscle in varying intensities in both groups. VLA‐6 reactivity was observed in the basal surfaces of arterial, venous and capillary endothelia. Our results indicate that there was no significant difference in the expression of VLA integrins in sound pulp tissue when compared to the samples from chronic (marginal) periodontitis and the connective tissue compartments of other viscera.

Conclusion

The present findings suggest that human dental pulp tissue is not different from other connective tissue compartments in the body with respect to VLA integrin expression, and chronic marginal periodontitis does not affect pulp tissue to a histopathologically detectable extent.
Digitization, analysis and processing of dental images during root canal preparation with Quantec Series 2000 instruments
Authors: Fabra‐Campos H. , Rodríguez‐Vallejo J.
Published: March 2003

Aim

The aim of this study was to determine the shaping ability of Quantec Series 2000 nickel–titanium instruments in the mesio‐buccal roots of maxillary first molars and the mesial roots of mandibular first molars.

Methodology

A total of 20 canals were prepared with Quantec instruments, adopting the technique recommended by the manufacturer. Each canal was sectioned horizontally into four and the canal in each portion photographed before and after preparation. The images obtained were digitized and the increase in canal surface for each quadrant of the four sections was evaluated, along with the variation in centre of mass after instrumentation.

Results

Mechanical instrumentation of the canals generated mean centre of mass displacements that did not vary between sections, except for the mid‐apical section, which showed significant mesial displacement, i.e. toward the side opposite the furcation. Thus, overall, the widening of the canal was symmetrical.

Conclusions

Under the conditions of the study, the Quantec Series 2000 rotary system was simple and safe to use, and created good three‐dimensional mechanical preparation of natural canals.
The standardized‐taper root canal preparation – Part 3. GT file technique in Large Root canals with small apical diameters
Authors: Buchanan L. S.
Published: March 2003

Aim

To describe the preparation of Large Root canals with small apical diameters by the GT file technique.

Large Root canals with small apical diameters can usually be prepared with one to three GT files; one to nine clinical steps, and one to five minutes of clinical time.

Following proper access, pulp tissue should be removed, and lubricant applied to prevent pulp compaction and blockage. Initial crown‐down enlargement is accomplished with up to three standard GT rotary files 0.10, 0.08 and 0.06 taper, running at 300 r.p.m., and with light touch. Care should be taken not to overload instruments, and they should be withdrawn, cleaned and inspected whenever they bind. Sometimes, the shaping objective is achieved with a single instrument; often waves of instrumentation are required before the shaping objective file cuts to length. Prior to cone‐fit, the apical resistance form is confirmed with conventional files, employed as feeler gauges of the tapering form created at the canal terminus. Regardless of the shaping time, canals should be soaked with sodium hypochlorite solution for at least 30 min for effective cleaning.

Key learning points

Large Root canals with small apical diameters should be prepared to shaping objectives 0.08 or 0.10 taper.

Compacted pulp tissue causes many canal blockages. It should be removed early, and canals should be well lubricated.

Large Root canals with small apical diameters should be prepared in crown‐down sequence, with recapitulation of steps until the shaping objective is achieved.

Apical resistance form should always be confirmed before cone‐fit.

Canals should be exposed to sodium hypochlorite for at least 30 min for effective cleaning.
The standardized‐taper root canal preparation – Part 4. GT file technique in Large Root canals with large apical diameters
Authors: Buchanan L. S.
Published: March 2003

Aim

To describe the GT file shaping steps required to create apical resistance in the presence of a wide root apex.

Canals are occasionally encountered with apices wider than 0.25 mm. These can be some of the most difficult to manage with conventional instruments, and overfills are common. Shaping such canals with GT files requires a paradigm shift of thinking, extending tapered files through the apex to create linear resistance in the apical few mm of the canal. GT standard and accessory files allow canals with apices up to around 0.7 mm to be prepared for tapered gutta percha cone‐fit. Apices larger than this should be considered too large for further shaping, and repaired with MTA before filling.

Key learning points

Tapered apical preparations offer optimal resistance form for obturation.

Tapered apical preparations can be prepared in most roots with wide apices by extending GT files and GT accessory files to or through the apex.

Apices wider than 0.7 mm should be repaired with MTA prior to filling.
Periradicular surgery of molars: a prospective clinical study with a one‐year follow‐up
Authors: Von Arx T. , Gerber C. , Hardt N.
Published: March 2003

Aim

The purpose of this prospective clinical study was to evaluate the outcome of periradicular surgery of molars after one year.

Methodology

The material consisted of 25 molars with 39 roots demonstrating periradicular lesions of endodontic origin. Surgical treatment included root‐end resection, root‐end preparation with sonic microtips, and root‐end filling with Super‐EBA cement. At the one‐year follow‐up examination, healing was evaluated clinically and radiographically. Healing was assigned to three categories: (i) success (ii) improvement, and (iii) failure using well defined criteria.

Results

Eighty‐eight per cent of the surgically treated molars showed successful healing. In 8%, the healing was rated as improved and only 4% were failures.

Conclusions

The outcome of the present study and data of recently published studies show that periradicular surgery may result in a predictable treatment outcome in molars with persistent periradicular lesions.
Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 2. Root‐canal‐filling materials
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 2. Root‐canal‐filling materials. International Endodontic Journal, 36, 147–160, 2003.

Root‐canal‐filling materials are either placed directly onto vital periapical tissues or may leach through dentine. The tissue response to these materials therefore becomes important and may influence the outcome of endodontic treatment. This paper is a review of the biocompatibility of contemporary orthograde and retrograde root‐canal‐filling materials.
Characterization and expression of a stage specific antigen by monoclonal antibody TRA 54 in testicular germ cells
Authors: PEREIRA  , TANAKA  , NAGATA  , SAWADA  , MORI  , CHIMELLI  , NISHIMUNE
Published: March 2003

To study the mechanism of spermatogenesis, we have isolated many monoclonal antibodies (mAb) which recognize specific steps of mouse germ cell differentiation and then have evaluated the specific expression and characterization of antigenic molecules using immunohistochemistry and Western blotting. Monoclonal antibody TRA 54 recognized specific organelles in germ cell cytoplasm from spermatocytes to spermatids; that is, a large granule was stained in mid–late pachytene, diplotene and secondary spermatocytes and in round spermatids at stage I while the acrosome of spermatids at steps 2–3 to step 12 were also positive. Thereafter, the antigens disappeared from spermatids at more advanced stages of differentiation. Western blots using TRA 54 revealed broad bands with approximate molecular weights of >200, 190 and 85 kDa in the testis. The expression of these antigens during testicular germ cell development should be of interest in relation to the biogenesis of organelles such as the chromatoid body and acrosome and will be a useful stage‐specific molecular marker for the study of spermatogenesis.
Immunohistochemical detection of testicular macrophages during the period of postnatal maturation in the mouse
Authors: LI  , ITOH  , YANO  , MIYAMOTO  , TAKEUCHI
Published: March 2003

In the present study, the distribution of F4/80, a highly specific antigen of murine macrophages, was studied in the testes of maturing ICR mice to investigate postnatal development of testicular macrophages. The antigen was immunohistochemically identified at the light microscopic level on days 0, 7, 14, 21, 28 and 42 and at 8 weeks after birth. Only a few macrophages were present between developing seminiferous tubules on day 0, but by day 7, the cell density of macrophages in the interstitium was significantly increased. Although the cell processes of the macrophages were very short on days 0 and 7, it was found that their cell processes were extended on days 14 and 21. On day 28, it was observed that the cell density of macrophages increased further and their cell processes became longer, resulting in the formation of a network between adjacent macrophages. Thereafter, the interstitial spaces were found to be narrower due to the increasing diameter of developing seminiferous tubules, although similar physical contact between the testicular macrophages to that seen on day 28 was evident. Moreover, the cell density of macrophages at 8 weeks of age did not differ significantly compared with that on day 28. These results demonstrate that testicular macrophages develop rapidly for the first 4 weeks in the mouse testis.
Degeneration of the seminiferous epithelium with ageing is a cause of spermatoceles?
Authors: Itoh  , Li  , Miyamoto  , Takeuchi
Published: March 2003

A spermatocele refers to the cystic accumulation of semen in the male reproductive tract. Although it is thought to be caused by narrowing of the lumen of the excurrent duct with resultant cystic dilatation of the duct, the pathogenesis of the narrowing remains unknown. In the present study, we histologically examined spontaneous spermatoceles in C3H/He mice to elucidate the pathogenesis of the lesions. Testes, efferent ducts, epididymides and vas deferens obtained from young and aged C3H/He mice were embedded in plastic for histological observation at the light microscopic level. It was found that spontaneous spermatoceles were localized in the rete testis and efferent ducts of aged mice, as seen in man. The dilated rete testis and efferent ducts contained many degenerated and aggregated germ cells derived from the exfoliated seminiferous epithelium in the aged testis. In particular, it was noted that the agglutinated germ cells obstructed the narrow lumen of the efferent ducts, resulting in the failure of transport of germ cells to the caput epididymis, and spermatoceles were consistently found in the region between the rete testis and the obstructed site in the efferent ducts. However, no inflammatory cell infiltration, traumatic injury or spermatic granulomas were found in the occluded region. These results suggest that agglutinated germ cells may occupy the narrow lumen of the efferent ducts, resulting in the formation of a spermatocele. It may be that a senile change to the seminiferous epithelium, which releases immature germ cells into the lumen of the seminiferous tubules, is the cause of this type of spermatocele.
Effects of transforming growth factor β‐1 and all‐trans‐retinoic acid on androgen‐induced development of neonatal mouse bulbourethral glands in vitro
Authors: Tanji Nozomu , Rahman ShaR. A. , Terada Nobuyuki , Yokoyama Masayoshi , Cunha Gerald R.
Published: March 2003

Effects of transforming growth factor β‐1 (TGF‐β1) and all‐trans‐retinoic acid (All‐trans‐RA) on development of bulbourethral glands (BUGs) of neonatal mice were investigated in vitro. BUGs from 0‐day‐old male mice were cultured for 6 days in serum‐free, chemically defined medium containing transferrin and bovine serum albumin, supplemented with 5α‐dihydrotestosterone (DHT; 10–8 M) and insulin (10 μg/mL) alone or in combination. Prior to culture, BUGs from 0‐day‐old mice consisted of a simple epithelial rudiment encapsulated by mesenchyme. Epithelial growth and ductal branching occurred in BUGs cultured in medium containing DHT and insulin or DHT alone, but epithelial branching did not occur in BUGs cultured in the presence of insulin alone. Addition of TGF‐β1 at concentrations of > 5 ng/mL (0.2 × 10–9 M) to medium containing both insulin and DHT, inhibited the expected increase in overall size of BUGs, epithelial area and ductal branching in a dose‐dependent manner. TGF‐β1 also decreased [3H]‐thymidine labelling indices of both epithelium and mesenchyme. TGF‐β1 at 10 ng/mL elicited these inhibitory effects on BUGs cultured in medium containing DHT alone. Addition of All‐trans‐RA (10–8 to 10–6 M) to the medium containing DHT plus insulin, or DHT alone did not exert significant effects on either overall size of BUGs or epithelial growth and ductal branching. All‐trans‐RA at 10–6 M decreased the [3H]‐thymidine labelling index of mesenchyme of BUGs cultured in medium with DHT plus insulin or DHT alone, but did not decrease the [3H]‐thymidine labelling index of epithelium. The present results indicate that TGF‐β1 inhibits androgen‐induced epithelial and mesenchymal growth as well as epithelial morphogenesis of BUGs from neonatal mice. Such an inhibitory effect of TGF‐β1 is not mimicked by All‐trans‐RA at physiological concentrations.
Ultracytochemical localization of 5′‐nucleotidase activity in human ejaculated spermatozoa
Authors: Takayama  , Matsubara  , Shibahara  , Minakami  , Takizawa  , Sato
Published: March 2003

5′‐nucleotidase, an adenosine producing enzyme with a glycosylphosphatidylinositol‐anchored structure, was localized in human ejaculated spermatozoa. The poly‐L‐lysine‐coated dish method was used to prepare the specimens, and the cerium method was employed for electron‐microscopic enzyme localization. Precipitates indicating enzyme activity were detected on the outer side of the external plasma membrane of the acrosomal region. This enzyme may play a role in sperm motility and male infertility.
True corrected seminal fructose level: a better marker of the function of seminal vesicles in infertile men
Authors: Gonzales Gustavo F. , Villena Arturo
Published: March 2003

This study was designed to determine if the value obtained after multiplying motile sperm concentration by seminal fructose concentration, named ‘true corrected fructose’, correlates with sperm motility in asthenozoospermic men. Forty‐two male partners in infertile couples were studied. Men were treated with 100 mg daily of clomiphene citrate for 5 days. Blood and semen samples were collected before treatment and 24 h after the end of treatment. Serum testosterone, seminal fructose and sperm motility were measured in each subject. Corrected fructose (log. sperm concentration multiplied by seminal fructose), and true corrected fructose (log. motile sperm concentration multiplied by seminal fructose) values were calculated. Prevalence of asthenozoospermia was 42.85% (18 of 42). Prevalence of hypofunction of the seminal vesicles was 9.5% using seminal fructose as a marker; 40.5% using seminal corrected fructose as a marker and 47.6% using true corrected fructose as a marker of seminal vesicle function. Regression analysis showed a better coefficient of determination between true corrected fructose and motile sperm concentration (R2=0.20, p < 0.001) than with corrected fructose (R2=0.05, p < 0.1) or fructose concentration (R2=0.006, p < 0.5). Asthenozoospermia was observed in 22.7% of subjects with normal function of the seminal vesicles, and in 65% of men with low values of true corrected fructose (z=6.02, p < 0.0001). Multivariate analysis showed that sperm motility grade 3 improved after treatment with clomiphene if true corrected fructose increased (p < 0.002). In those men whose seminal vesicle function improved after clomiphene treatment, a reduction in the prevalence of asthenozoospermia from 50 to 28.6% (z=3.10, p < 0.002) was observed whereas in those whose seminal vesicles did not respond to clomiphene the prevalence of asthenozoospermia was not reduced (z=1.05; p: NS). In conclusion, true corrected fructose measurement relates with sperm motility in cases of asthenozoospermia. Asthenozoospermia improves with clomiphene treatment if seminal vesicle function improves after treatment.
The clinical studies of sildenafil for the ageing male
Authors: Tsujimura Akira , Yamanaka Masaki , Takahashi Toru , Miura Hidenobu , Nishimura Kenji , Koga Minoru , Iwasa Atsushi , Takeyama Masami , Matsumiya Kiyomi , Takahara Shiro , Okuyama Akihiko
Published: March 2003

Erectile dysfunction (ED) represents an important quality‐of‐life issue for many ageing men. Low serum testosterone level and other factors may be involved. Sildenafil is effective and well tolerated in patients with ED of various aetiologies, showing an efficacy of about 75%. However, few efficacy and adverse effect studies have focused specially on ageing men. In 150 patients below 65 years and 44 patients over 65 years, sildenafil was used to treat ED. Efficacy in the younger group (89.1%) was greater than in the older group (65.7%; p < 0.01). Mean serum luteinizing hormone (LH) and follicle‐stimulating hormone concentrations (11.0 and 18.9 mIU/mL, respectively) in the older group were higher than in younger group (5.2 and 8.7 mIU/mL, respectively; p < 0.01). Serum testosterone and prolactin (PRL) were similar between groups. Older patients showed higher prevalence of diabetes mellitus, hypertension, and benign prostatic hyperplasia. Only diabetes appeared to decrease efficacy of sildenafil in older patients ( p=0.019). A high prevalence of diabetes might be one of the many causes of lower efficacy rate of sildenafil in older men, although efficacy in patients even without diabetes in older men was relatively low. Sildenafil can be used safely and it is still effective for ageing male, because nearly two‐thirds of our older subjects had a good response to the drug and no adverse effect was specific to older patients.
A novel homozygous disruptive mutation in the SRD5A2‐gene in a partially virilized patient with 5α‐reductase deficiency
Authors: Hiort Olaf , Schütt Snjezana M. , Bals‐Pratsch Monika , Holterhus Paul‐Martin , Marschke Christine , Struve Dagmar
Published: March 2003

Steroid 5α‐reductase deficiency is a rare autosomal recessive disorder caused by mutations in the SRD5A2‐gene, resulting in diminished dihydrotestosterone (DHT) formation and, hence, in a severe virilization deficit of the external genitalia in patients with 46,XY karyotype. The phenotype of affected individuals is variable and has been reported to range from completely female over genital ambiguity to normal male, depending on the type of mutation and its effect on enzyme activity. Here we report an adolescent 46,XY patient with predominantly female appearance, who had been gonadectomized in early infancy. Genital status revealed a urogenital sinus equivalent to Prader stage III. Molecular genetic analysis demonstrated a homozygous point mutation in exon 2 of the SRD5A2‐gene, leading to a premature termination in codon position 111 of the 5α‐reductase 2 enzyme, and not allowing formation of a functional 5α‐reductase type 2 enzyme. This case demonstrates that even despite a complete loss of function of 5α‐reductase type 2, marked virilization is possible, most likely the result of a testosterone (T) effect during foetal life.
Impact of obesity on hypogonadism in the andropause
Authors: Tan R. S. , Pu S. J.
Published: March 2003

Obesity is an issue that is increasingly affecting ageing men. With ageing, there is a decline in androgens as well. There are implications for the health of ageing men as a result of hypogonadism. Overall, there seems to be an inverse relationship between body mass index and testosterone levels, as is also demonstrated in our cross‐sectional study. Obesity seems to depress the production of testosterone. It has been hypothesized that there is increased aromatization of testosterone to oestradiol and alteration of the hypothalamic–pituitary–adrenal axis in obese older men. Some hormones can affect obesity in ageing men including leptin, insulin, dehydroepiandrostenedione and growth hormone. The relationship of obesity to these hormones in ageing men will be reviewed. Testosterone replacement in ageing men can alter body composition whereby fat is exchanged for muscle. These studies will also be reviewed. Further studies in this field are recommended to evaluate long‐term benefits and risks.