bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractThe 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.
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.
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

AbstractAimThe 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.MethodologyFreshly 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.ResultsVLA‐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.ConclusionThe 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

AbstractAimThe 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.MethodologyA 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.ResultsMechanical 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.ConclusionsUnder 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

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

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

AbstractAimThe purpose of this prospective clinical study was to evaluate the outcome of periradicular surgery of molars after one year.MethodologyThe 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.ResultsEighty‐eight per cent of the surgically treated molars showed successful healing. In 8%, the healing was rated as improved and only 4% were failures.ConclusionsThe 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

Abstract 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.
Impact of obesity on hypogonadism in the andropause
Authors: Tan R. S. , Pu S. J. 
Published: March 2003

SummaryObesity 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.
False‐positive Y‐microdeletion result for a fertile male caused by an alteration under a PCR primer
Authors: THORNHILL A. R. , GUENTHER A. J. , BARBAROTTO G. M. , SESSION D. R. , DAMARIO M. A. , DUMESIC D. A. , SNOW K. 
Published: March 2003

SummaryThe pathogenic relationship between the presence of Y chromosomal microdeletions and male infertility is unclear. Nevertheless, a causal relationship is thought to be probable when loci are shown to be deleted in infertile males but are present in fertile males. Polymerase chain reaction (PCR) analysis of the Y chromosome is now routinely performed in the evaluation of the infertile male, although, until recently, there has been no consensus on how the diagnosis should be performed and which loci or markers should be analysed. The European Academy of Andrology (EAA) published guidelines for the molecular diagnosis of Y chromosomal microdeletions in 1999. Following these guidelines, our laboratory developed assays that incorporated the suggested primer pairs for the recommended Sequence Tagged Sites (STS). A number of fertile (n = 117), infertile (n = 17) and unknown samples (n = 20) were tested in our laboratory as part of the validation to provide a clinical assay. Two multiplex PCR assays were optimized, each of which examined STS markers in the centre of the AZFa, b and c regions of the Y chromosome. We correctly identified all but one of the 154 samples (according to the expected result based on fertility or previous testing at another laboratory). A single equivocal result was observed for a sample obtained from a known fertile male who appeared to be deleted for a single marker, sY84, in the AZFa region but not the adjacent marker, sY86. Follow‐up analysis showed that proximal and distal markers within the same region (sY82 and sY98) were also present. Sequencing the region flanking and including the sY84 primer set revealed a single base alteration under the reverse primer, which probably caused the amplification failure. Furthermore, the sY84 sequence itself was present, as was the flanking sequence 50 bp on either side of both primers. This observation underlines the importance of using at least two closely linked STS markers for the reliable diagnosis of Y chromosome microdeletions as proposed by the EAA guidelines.
Molecular biology and pathogenesis of the human T‐cell leukaemia/lymphotropic virus Type‐1 (HTLV‐1)
Authors: Johnson Julie M. , Harrod Robert , Franchini Genoveffa 
Published: March 2003

Retroviruses are associated with a variety of diseases, including immunological and neurological disorders, and various forms of cancer. In humans, the Human T‐cell Leukaemia/Lymphotropic virus type 1 (HTLV‐1), which belongs to the Oncovirus family, is the aetiological agent of two diverse diseases: Adult T‐cell leukaemia/lymphoma (ATLL) (Poiesz et al. 1980; Hinuma et al. 1981; Yoshida et al. 1982), as well as the neurological disorder tropical spastic paraparesis/HTLV‐1‐associated myelopathy (TSP/HAM) (Gessain et al. 1985; Rodgers‐Johnson et al. 1985; Osame et al. 1986). HTLV‐1 is the only human retrovirus known to be the aetiological agent of cancer.A genetically related virus, HTLV‐2, has been identified and isolated (Kalyanaraman et al. 1982). However, there has been no demonstration of a definitive aetiological role for HTLV‐2 in human disease to date. Simian T‐cell lymphotropic viruses types 1 and 2 (STLV‐1 and ‐2) and bovine leukaemia virus (BLV) have also been classified in same group, Oncoviridae, based upon their similarities in genetic sequence and structure to HTLV‐1 and ‐2 (Burny et al. 1988; Dekaban et al. 1995; Slattery et al. 1999). This article will focus on HTLV‐1, reviewing its discovery, molecular biology, and its role in disease pathogenesis.