bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation of cDNA clones encoding putative odourant binding proteins from the antennae of the malaria‐transmitting mosquito, Anopheles gambiae
Authors: Biessmann Harald , Walter Marika F. , Dimitratos Spiros , Woods Daniel 
Published: March 2003

AbstractOne way of controlling disease transmission by blood‐feeding mosquitoes is to reduce the frequency of insect–host interaction, thus reducing the probability of parasite transmission and re‐infection. A better understanding of the olfactory processes responsible for allowing mosquitoes to identify human hosts is required in order to develop methods that will interfere with host seeking. We have therefore initiated a molecular approach to isolate and characterize the genes and their products that are involved in the olfactory recognition pathway of the mosquito Anopheles gambiae, which is the main malaria vector in sub‐Saharan Africa. We report here the isolation and preliminary characterization of several cDNAs from male and female A. gambiae antennal libraries that encode putative odourant binding proteins. Their conceptual translation products show extensive sequence similarity to known insect odourant binding proteins (OBPs)/pheromone binding proteins (PBPs), especially to those of D. melanogaster. The A. gambiae OBPs described here are expressed in the antennae of both genders, and some of the A. gambiae OBP genes are well conserved in other disease‐transmitting mosquito species, such as Aedes aegypti and Culex quinquefasciatus.
Germ‐line transformation of the South American malaria vector, Anopheles albimanus, with a piggyBac/EGFP transposon vector is routine and highly efficient
Authors: Perera O. P. , Harrell II R. A. , Handler A. M. 
Published: March 2003

AbstractStable and efficient germ‐line transformation was achieved in the South American malaria vector, Anopheles albimanus, using a piggyBac vector marked with an enhanced green fluorescent protein gene regulated by the Drosophila melanogaster polyubiquitin promoter. Transgenic mosquitoes were identified from four independent experiments at frequencies ranging from 20 to 43% per fertile G0. Fluorescence was observable throughout the body of larvae and pupae, and abdominal segments of adults. Transgenic lines analysed by Southern hybridization had one to six germ‐line integrations, with most lines having three or more integrations. Hybridized transposon vector fragments and insertion site sequences were consistent with precise piggyBac‐mediated integrations, although this was not verified for all lines. The piggyBac/PUbnlsEGFP vector appears to be a robust transformation system for this anopheline species, in contrast to the use of a piggyBac vector in An. gambiae. Further tests are needed to determine if differences in anopheline transformation efficiency are due to the marker systems or to organismal or cellular factors specific to the species.
cDNA cloning, functional expression and characterization of kynurenine 3‐hydroxylase of Anopheles stephensi (Diptera: Culicidae)
Authors: Hirai M. , Kiuchi M. , Wang J. , Ishii A. , Matsuoka H. 
Published: March 2003

AbstractKynurenine 3‐hydroxylase (K3H) is a NADPH‐dependent flavin monooxygenase involved in the tryptophan pathway. Xanthurenic acid (XA) is a metabolite of this pathway and has recently been identified as a gamete activating factor (GAF) of the malarial parasite. We cloned K3H cDNA from Anopheles stephensi (AsK3H), because anopheline mosquitoes are a vector of the human malaria parasite, Plasmodium falciparum and the catalytic function of AsK3H in XA production. Recombinant AsK3H protein was expressed in Sf‐9 cells using the baculovirus system and its enzymatic properties were characterized. The specific activities of crude cell lysate and affinity purified protein were 94.9 ± 6.2 and 865.6 ± 10.5 nmol/min/mg protein, respectively. The optimum pH of AsK3H was 7.0. Analysis of AsK3H gene expression using RT‐PCR revealed that AsK3H was constitutively expressed in egg, larva, pupa and adult.
A novel family of anticoagulants from the saliva of Ixodes scapularis
Authors: Narasimhan S. , Koski R. A. , Beaulieu B. , Anderson J. F. , Ramamoorthi N. , Kantor F. , Cappello M. , Fikrig E. 
Published: March 2003

AbstractUsing biochemical and molecular approaches, we have identified a 9.8 kDa protein in the saliva of Ixodes scapularis that inhibits the intrinsic pathway of coagulation. The 9.8 kDa anticoagulant protein was purified by reverse‐phase HPLC and its N‐terminal amino acid sequence determined. The N‐terminal sequence showed homology with Salp14, an immuno‐dominant antigen present in the saliva of engorging I. scapularis nymphs. Recombinant Salp14 expressed in Escherichia coli prolonged the activated partial thromboplastin time (APTT) of human plasma in a dose‐dependent manner and was a specific inhibitor of factor Xa. A cDNA encoding a 9.3 kDa protein, Salp9Pac, was subsequently isolated from an I. scapularis salivary gland cDNA library. Salp9Pac showed 93% identity to the N‐terminal sequence of the anticoagulant purified by HPLC. These data indicate that the anticoagulant protein purified by HPLC, Salp9Pac and Salp14 are members of a family of novel coagulation protease inhibitors present in tick saliva. While recombinant Salp9Pac did not show biological activity in the assays tested currently, it is likely to be mechanistically different from its paralogues. This raises the possibility that ticks may enhance their adaptive ability to cope with a wide spectrum of proteases, by transcribing such structurally related anticoagulant proteins with different functions.
Cytochrome P450 CYP6X1 cDNAs and mRNA expression levels in three strains of the tarnished plant bug Lygus lineolaris (Heteroptera: Miridae) having different susceptibilities to pyrethroid insecticide
Authors: Zhu Y. C. , Snodgrass G. L. 
Published: March 2003

AbstractThree cDNAs, cloned from both pyrethroid‐susceptible and ‐resistant strains of Lygus lineolaris, contained a 1548 nucleotide open reading frame encoding a 516 amino acid residue protein. Predicted cytochrome P450s from cDNAs were classified as the first three new members of subfamily CYP6X, CYP6X1v1 for a susceptible strain and CYP6X1v2 and CYP6X1v3 for two resistant strains. Putative cytochrome P450 CYP6X1s from L. lineolaris were highly similar (up to 42% amino acid sequence identity) to several insect CYP6s that are responsible for reduced sensitivity to pyrethroid insecticides. A total of twenty‐six nucleotide substitutions were revealed between cDNAs of susceptible and resistant strains. Two nucleotide substitutions resulted in amino acid changes, Asp373 to Ala373 and Ser487 to Ala487, between susceptible and resistant strains. The resistant laboratory strain contained 2.1‐fold higher cytochrome P450 mRNA per microgram total RNA than the susceptible laboratory strain. Topical treatment with 10 ng permethrin elevated cytochrome P450 mRNA levels by approximately 2‐fold. The results of this study indicated that cytochrome P450 gene mutation, coupled with up‐regulation, was present only in the pyrethroid resistant strains, and was possibly related to resistance development in the tarnished plant bug.
A scanning electron microscopic evaluation of root surfaces and the gutta‐percha interface following root‐end resection in vitro
Authors: Weston G. D. , Moule A. J. , Bartold P. M. 
Published: March 2003

Weston GD, Moule AJ, Bartold PM. A scanning electron microscopic evaluation of root surfaces and the gutta‐percha interface following root‐end resection in vitro. International Endodontic Journal, 32, 450–458 1999.Aim The aim of this study was to evaluate the effects that various commonly used instruments have on root surface morphology, the obturating material, and the interface between the obturation and the root canal walls following root‐end resection in vitro.Methodology Sixty human single‐rooted teeth with fully formed apices were collected and decoronated. The root canals were instrumented, and then obturated with thermoplasticized gutta‐percha using AH‐26 as the sealer. The roots were randomly divided into 12 different groups, and apical root‐end resections were performed using eight different instrument configurations, and two different directions in which the bur moved across the root face in relation to its direction of rotation. Epoxy resin replicas of the resected root ends were examined using scanning electron microscopy.Results Each instrument produced a characteristic surface finish on the resected root end that mirrored its cutting profile. Irrespective of the design of the bur used, smearing and shredding of the gutta‐percha across the root face occurred only when the handpiece was moved across the root face in reverse direction in relation to the direction of rotation of the bur.Conclusions To ensure minimal disruption and distortion of the root filling and to prevent shredding of the gutta‐percha interface, care should be taken to ensure that the final pass of the bur across the root canal is in the correct direction in relation to its direction of rotation.
Preclinical endodontology: an international comparison
Authors: Qualtrough A. J. E. , Whitworth J. M. , Dummer P. M. H. 
Published: March 2003

Aim The aim of this study was to compare preclinical endodontic teaching in Europe, Scandinavia and North America, and to place recent UK data in an international context.Methodology A postal questionnaire was sent to all undergraduate dental schools in North America, Scandinavia, and Europe. Data were requested on a range of issues relating to endodontic teaching.Results Forty‐three percent of the 170 schools surveyed returned completed questionnaires. There was considerable international consensus on the content of preclinical courses, with most schools advocating preflaring canal preparation techniques, sodium hypochlorite for irrigation, and cold lateral condensation as the standard obturation method. There was little consensus on the standard use of intracanal medicaments, though calcium hydroxide was universally popular. The practice of single visittreatment was advocated by at least 70% of schools in all geographical areas.A number of innovations appear to be gaining acceptance in preclinical teaching, with more than 20% of schools teaching the use of electronic apex locators, and a quarter of Western European, Scandinavian and North American schools embracing nickel‐titanium instrumentation. Regional differences in the priority and resource given to endodontic teaching were striking. On average, UK schools had the worst staff:student ratios for preclinical endodontic teaching, and allocated substantially less time allocation for this teaching compared with Western European, Scandinavian and North American schools.Conclusions It was concluded that although teachers in the UK were broadly advocating techniques recommended elsewhere, the academic infrastructure and priority given for endodontic teaching in the UK was limited in the international context. This may have some impact on the quality of endodontic provision within the UK General Dental Services.
The preparation of periapical lesions for flow cytometry
Authors: Fernando K. , Gulabivala K. , Barrett A. W. 
Published: March 2003

Aim  To devise an optimal protocol and to analyse the leucocyte composition of periapical (PA) lesions by flow cytometry.Methodology PA lesions were mechanically agitated, with and without proteolysis. This was with either 0.2% collagenase alone, or in combination with 0.02% DNA‐ase in serial incubations until all tissue was digested. The efficacy of each method was assessed by counting total cell yield and cell viability. Phenotype stability was gauged by the percentage of peripheral blood leucocytes (PBL) which expressed CD45RB, CD3, CD20, CD4 and CD8 before and after mechanical and collagenase treatment.Results  Disaggregation of PA lesions was superior if collagenase was present, but cell clumping was problematic unless the DNA‐ase was also added, and serial digestion with this combination produced optimal cell yield and viability. Nevertheless, the total number of cells released rarely exceeded 105, though viability was in excess of 80%. Mechanical agitation and proteolysis adversely affected PBL phenotypes, but collagenase digestion limited to 10 min caused least damage. Flow cytometric analysis of disaggregated PA lesions failed to identify more than 7.9% (mean, range 6–10%) CD45RB + cells.Conclusions  Because of the necessity for single cell suspensions, flow cytometry is not easily applied to the analysis of leucocytes in PA lesions, and further refinements in tissue disaggregation and cell preparation are required.
A survey of interfacial forces used during endosonic instrumentation of root canals
Authors: Regan J. D. , Sherriff M. , Meredith N. , Gulabivala K. 
Published: March 2003

AbstractAimThe aim of thisin‐vitrostudy was to measure interfacial forces acting between root canal dentine and ultrasonic files during endosonic instrumentation.MethodologySingle‐rooted teeth were mounted on a cantilevered aluminium beam to which two pairs of single element strain gauges were joined in a half‐bridge configuration mounted at right angles to each other. The strain gauges were connected to an analogue‐to‐digital converter fitted in a microcomputer via a conditioning amplifier. This enabled strains to be recorded as a function of interfacial forces over a period of time. Twenty operators instrumented root canals using sizes 15, 20 and 25 ultrasonically energized K‐type files. The lateral forces generated were calculated.ResultsThe mean interfacial forces used varied widely between operators and files, ranging from 18 g to 149 g, but there was a consistency in the relative magnitude for each operator. The average force used by the operators increased with file size; the differences between file sizes were significant (P < 0.05).ConclusionsThe range of forces measured is broader than previously reported and may have a bearing on possible uncontrolled dentine removal, even during ultrasonically activated irrigation.
Inactivation of root canal medicaments by dentine, hydroxylapatite and bovine serum albumin
Authors: Portenier I. , Haapasalo H. , Rye A. , Waltimo T. , Ørstavik D. , Haapasalo M. 
Published: March 2003

AbstractAim This study examined and compared the inhibition of the antibacterial effect of saturated calcium hydroxide solution, chlorhexidine acetate and iodine potassium iodide by dentine, hydroxylapatite and bovine serum albumin.Methodology Enterococcus faecalis strain A197A prepared to a suspension of 3 × 108 cells per ml in 0.5% peptone water was used. Fifty µL of saturated calcium hydroxide solution, 0.05% chlorhexidine acetate or 0.2/0.4% iodine potassium iodide were incubated at 37 °C with 28 mg dentine powder (DP), hydroxylapatite (HA) or bovine serum albumin (BSA) in 50 µL water for 1 h before adding 50 µL of the bacterial suspension. Samples for bacterial culturing were taken from the suspension 1 and 24 h after adding the bacteria. In further experiments, the amount of dentine was stepwise reduced from 28 mg 150 µL−1 to 2.8 mg 150 µL−1.Results Calcium hydroxide was totally inactivated by the presence of 28 mg of DP, HA or BSA. Chlorhexidine (0.05%) was strongly inhibited by BSA and slowed down by dentine. However, HA had little or no inhibitory effect on chlorhexidine. The antibacterial effect of 0.2/0.4% iodine potassium iodide on E. faecalis was totally inhibited by dentine (28 mg), but was practically unaffected by HA or BSA. A stepwise reduction of dentine from 28 mg 150 µL−1 to 2.8 mg 150 µL−1 was followed by a similar reduction of the inhibition of the antibacterial activity of chlorhexidine. Iodine potassium iodide was not inhibited at all with dentine amounts less than 28 mg. However, the effect of saturated calcium hydroxide solution was totally eliminated by dentine, in all four concentrations.Conclusion Inhibition by dentine of the antibacterial activity of calcium hydroxide, chlorhexidine and iodine potassium iodide occurs by different mechanisms. Different components of dentine may be responsible for the inhibition of these three medicaments. Calcium hydroxide was particularly sensitive to inhibition by both inorganic and organic compounds.
The outcome of endodontic resurgery: a systematic review
Authors: Peterson J. , Gutmann J. L. 
Published: March 2003

AbstractAim The aim of this paper is to establish an outcome standard for the assessment of healing radiographically after resurgery of persistent periradicular lesions by systematically reviewing the results from published studies.Methodology The systematic review process requires the definition of predetermined criteria delineating the inclusion parameters of studies reviewed. Of 42 papers that were reviewed, eight qualified for inclusion. A weighted‐average was calculated from the results taken from the eight eligible, peer‐reviewed studies, published between 1970 and 1997.Results Three hundred and thirty patients out of 2375 (14%) from the included studies underwent resurgery for failure of healing as determined radiographically. Of this population, 35.7% healed successfully after resurgery, 26.3% healed with uncertain results and 38% did not heal at the one‐year follow‐up.Conclusions Although there is nearly equal distribution of results between all categories, a 35.7% rate of healing as assessed radiographically is essentially equivalent to the 38% failure rate. This paper will allow an evaluation of current research results to establish an outcome standard and enable techniques and filling materials to be evaluated and compared. Furthermore, the outcome standard can assist in defining demographic and aetiological factors that contribute to the potential outcome of resurgery cases.
An in vitro evaluation of the antimicrobial efficacy of irrigants on biofilms of root canal isolates
Authors: Spratt D. A. , Pratten J. , Wilson M. , Gulabivala K. 
Published: March 2003

AbstractAimThe bactericidal effect of four antimicrobial agents was investigated against single‐species biofilms derived from a range of root canal isolates.MethodologySingle‐species biofilms of Prevotella intermedia, Peptostreptococcus micros, Streptococcus intermedius, Fusobacterium nucleatum and Enterococcus faecalis were generated on membrane filter discs and subjected to 15 min or 1 h incubation with 5 p.p.m. colloidal silver, 2.25% sodium hypochlorite (NaOCl), 0.2% chlorhexidine, 10% iodine or phosphate buffered saline (PBS) as a control. The antimicrobial activity of the agents was neutralized and the bacterial cells were harvested from the discs by vortexing, serially diluted in reduced transport fluid, plated on fastidious anaerobe agar containing 5% horse blood, incubated anaerobically and colony‐forming units calculated.ResultsIodine and NaOCl were more effective than chlorhexidine except against P. micros and P. intermedia where they were all 100% effective. Iodine and NaOCl elicited a 100% kill after 1 h incubation for all strains used. However, after 15 min, they showed differing bactericidal effects depending on the strain. None of the agents were effective against F. nucleatum after 15 min but NaOCl, iodine and chlorhexidine were all effective after 1 h. Colloidal silver was generally ineffective.ConclusionsThe effectiveness of a particular agent was dependent on the nature of the organism in the biofilm and on the contact time. NaOCl was generally the most effective agent tested, followed by iodine. However the clinical efficacy of these agents must be considered in light of the complex root canal anatomy and polymicrobial nature of root canal infections.
The influence of preparation technique and sodium hypochlorite on removal of pulp and predentine from root canals of posterior teeth
Authors: Evans G. E. , Speight P. M. , Gulabivala K. 
Published: March 2003

AbstractAimTo test the null hypothesis that removal of pulp tissue and predentine from root canals of multirooted teeth is not significantly different when performed by one of two mechanical preparation techniques in conjunction with either water or 3% sodium hypochlorite (NaOCl) irrigation.MethodologyForty‐six freshly extracted premolar or molar teeth, with pulps vital at the time of extraction, were assigned to four groups balanced by anatomy (group 1, step‐back filing/NaOCl; group 2, step‐back filing/water; group 3, automated rotary/NaOCl; group 4, automated rotary/water). Preparation was undertaken by a single operator and the volumes of irrigant recorded for each tooth. One root from each tooth was prepared for transverse histological assessment at eight levels, including one at and two apical to the working length. A validated index was used to measure the presence and location of residual pulp tissue and predentine.ResultsNo statistically significant differences were found in the frequency with which residual pulp tissue or predentine were observed amongst the groups. Coronal parts were more frequently devoid of pulp tissue and predentine than the apical. Canals were frequently occluded with residual pulp tissue apical to the working length. There was a trend for better pulp and predentine removal in accessible parts of the canal as a function of rotary preparation and NaOCl irrigation. The isthmus had residual pulp tissue less frequently in the NaOCl groups. Accessory anatomy was unaffected regardless of technique or irrigant.ConclusionsPulp tissue and predentine removal were not significantly different between a step‐back filing and an automated rotary preparation technique in conjunction with water or NaOCl.
Root and canal morphology of Burmese maxillary molars
Authors: Ng Y‐L. , Aung T. H. , Alavi A. , Gulabivala K. 
Published: March 2003

AbstractAimTo investigate the root and canal morphology of Burmese maxillary molars using a canal staining and tooth clearing technique.MethodologyMaxillary molars (239) were collected from indigenous Burmese patients and designated; first (90), second (77), third (72) molars. Following pulp tissue removal and canal system staining with Indian ink, the teeth were decalcified with 10% nitric acid, dehydrated and cleared with methyl salicylate. The following features were evaluated: (i) number of roots and morphology; (ii) number of canals per root; (iii) root canal configuration (Vertucci's classification); (iv) number of apical foramina per root; (v) number and location of lateral canals; and (vi) the presence of intercanal communications.ResultsAll first and second molars had three separate roots, whilst third molars had one of five different root forms, of which three separate (25%) or fused (31%) roots were most prevalent. The majority of palatal (100%) and disto‐buccal (96%) roots possessed one canal (type I). The prevalence of mesio‐buccal roots with two canals decreased from first to third molars (68%, 49%, 39%, respectively); type II (two orifices, one apical foramen) and IV (two orifices, two apical foramina) configurations were the most common. Single/fused rooted third molars had a range of number and type of canals. Most roots in all molars had one apical foramen, those with four apical foramina were confined to third molars. Intercanal communications were most prevalent in mesio‐buccal roots and two/three fused rooted third molars. Lateral canals were most prevalent in the apical third of the roots of all molars.ConclusionsThe mesio‐buccal roots of Burmese maxillary molars possessed a variety of canal system types. Over 50% of the first and second molars had a second mesio‐buccal canal, of which over 20% had intercanal communications. The palatal and disto‐buccal canals mainly had type I canals. Lateral canals were equally prevalent in all tooth types but were most common in the apical third.