bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new staphylococcal sigma factor in the conserved gene cassette: functional significance and implication for the evolutionary processes
Authors: Morikawa Kazuya , Inose Yumiko , Okamura Hideyuki , Maruyama Atsushi , Hayashi Hideo , Takeyasu Kunio , Ohta Toshiko 
Published: July 2003

AbstractBackground:  Staphylococcus aureus is a major human pathogen and causes a serious hospital infection due to the acquired multidrug resistance. Unlike the well‐studied bacteria such as Escherichia coli and Bacillus subtilis, which have seven and 18 sigma factors, respectively, only two sigma factors have been known for S. aureus. We searched for possible sigma factor genes by examining the S. aureus genome with a special attention to the gene arrangement around the sigma factor genes of a close relative, B. subtilis.Results:  A new sigma factor gene was identified in Staphylococcus. The gene constituted a conserved gene cluster with other genes including translation‐ and transcription‐related genes. Phylogenetic analysis and comparison of the gene sequences among species indicated that the staphylococcal sigma factor originated from a common ancestor of B. subtilis SigH. An over‐expression of this sigma factor in S. aureus resulted in a drastic induction of the expression of the com operons that encode proteins required for the natural genetic competence.Conclusions:  We demonstrated that the newly identified staphylococcal sigma factor participated in a regulatory network of transcription that controlled the genetic competence genes. In our phylogenetic tree, the factor was classified as a single group with a common function.
Temperature compensation and temperature resetting of circadian rhythms in mammalian cultured fibroblasts
Authors: Tsuchiya Yoshiki , Akashi Makoto , Nishida Eisuke 
Published: July 2003

AbstractBackground:  Circadian rhythms control many physiological processes. One of characteristic properties of circadian rhythms is insensitivity to temperature, called temperature compensation. Although this temperature‐insensitive property has repeatedly been observed mainly in circadian output rhythms, temperature effect on autoregulatory feedback loops of clock gene expression, the rhythm‐generating mechanisms, has not been fully investigated.Results:  We show first that the circadian oscillation of clock gene expression in NIH3T3 fibroblasts, which is induced by TPA (12‐O‐tetradecanoylphorbol‐13‐acetate) treatment, is strongly temperature‐compensated over the temperature range of 33−42 °C. We then show that heat treatment at 42 °C is able to trigger circadian oscillation of clock gene expression in NIH3T3 cells. This 42 °C heat treatment, unlike serum shock or TPA treatment, did not induce immediate expression of mPer1 mRNA, suggesting the existence of several different resetting mechanisms.Conclusions:  This is the first demonstration of temperature compensation of the rhythm‐generating core feedback loops of clock gene expression in mammalian cultured cells. It is possible that cells in the periphery could sense the change of ambient temperature as a resetting cue and that the whole organism thus could be entrained rapidly at dawn, in cooperation with the resetting mechanism by light.
Incidence of patent furcal accessory canals in permanent molars of a Turkish population
Authors: Haznedaroğlu F. , Ersev H. , Odabaşı H. , Yetkin G. , Batur B. , Aşçı S. , İşsever H. 
Published: July 2003

AbstractAim  To determine the incidence of patent furcal accessory canals in permanent molars of a Turkish population.Methodology  Two‐hundred extracted teeth consisting of 50 maxillary first molars, 50 maxillary second molars, 50 mandibular first molars and 50 mandibular second molars from Turkish patients attending the Oral Surgery Department of the Faculty of Dentistry, İstanbul University, İstanbul, Turkey, were included in the study. After preparation of access cavities and removal of pulp tissue, the teeth were stored in 5.25% sodium hypochlorite for 1 h. Following double‐sealing of the access cavities, all tooth surfaces except the furcation regions were covered with nail varnish. The teeth were stored in 0.5% basic fuchsin for 1 week. The teeth were sectioned at the cemento‐enamel junction and the presence of patent furcal canals was established by examining the pulp chamber floor with a stereomicroscope (10×) to determine staining.Results  Patent furcal accessory canals were detected in 24% of maxillary first molars, 16% of maxillary second molars, 24% of mandibular first molars, and 20% of mandibular second molars. No statistically significant differences were found between the tooth types.Conclusions  In a Turkish population, the incidence of patent furcal accessory canals on the pulp chamber floor of maxillary and mandibular first and second molars ranged between 16 and 24%.
A prospective clinical study of Mineral Trioxide Aggregate and IRM when used as root‐end filling materials in endodontic surgery
Authors: Chong B. S. , Pitt Ford T. R. , Hudson M. B. 
Published: July 2003

AbstractAim  To assess the success rate of the root‐end filling material, Mineral Trioxide Aggregate (MTA).Methodology  Referred adult patients were recruited using strict entry criteria and randomly allocated to receive MTA or IRM. A standardized surgical technique was employed: the root end was resected perpendicularly and a root‐end cavity was prepared ultrasonically and filled. A radiograph taken immediately after surgery was compared with those taken at 12 and 24 months. Customised film holders and the paralleling technique were used; radiographs were assessed by two trained observers using agreed criteria. The results from 122 patients (58 in IRM group, 64 in MTA group) after 12 months and 108 patients (47 in IRM group, 61 in MTA group) for the 24‐month review period were analysed using the χ2 test.Results  The highest number of teeth with complete healing at both times was observed when MTA was used. When the numbers of teeth with complete and incomplete (scar) healing, and those with uncertain and unsatisfactory healing were combined, the success rate for MTA was higher (84% after 12 months, 92% after 24 months) compared with IRM (76% after 12 months, 87% after 24 months). However, statistical analysis showed no significant difference in success between materials (P > 0.05) at both 12 and 24 months.Conclusions  In this study, the use of MTA as a root‐end filling material resulted in a high success rate that was not significantly better than that obtained using IRM.
Fluid movement along the coronal two‐thirds of root fillings placed by three different gutta‐percha techniques
Authors: Wu M.‐K. , Van Der Sluis L. W. M. , Ardila C. N. , Wesselink P. R. 
Published: July 2003

AbstractAim  To compare fluid movement (FM) along the coronal two‐thirds of gutta percha/sealer root fillings placed by three different techniques.Methodology  Three groups consisting of the roots of mandibular incisors were instrumented and obturated by cold lateral compaction (LC), warm vertical compaction (VC) or the single‐cone technique (SC), using RoekoSeal Automix (RSA) as the sealer. The apical 4 mm of each root filling was removed, and FM along the remaining 7 mm of the root filling was measured.Results  The VC group displayed more FM than the other two groups (P = 0.023). No significant difference in FM was found between the LC and SC groups (P = 0.629).Conclusions  The coronal two‐thirds of the VC root fillings did not prevent FM when RSA sealer was used.
The location of the cementodentinal junction in single‐rooted mandibular first premolars from Egyptian and Saudi patients: a histological study
Authors: Saad A. Y. , Al‐Yahya A. S. 
Published: July 2003

AbstractAim  To determine the location of the cementodentinal junction (CDJ) in mandibular first premolars from Egyptian and Saudi patients.Methodology  One hundred and twenty‐two extracted single‐rooted mandibular first premolars (68 Egyptian; 54 Saudi) were examined histologically. Half of the teeth were fixed, decalcified, embedded in paraffin, mesio‐distally sectioned and stained with H&E, whilst the other half were ground with a stone prior to microscopic evaluation. Measurements of the location of the CDJ were made parallel to the long axis of the teeth from the external surface of the root apex on the mesial and distal sides of the canal. Measurements were statistically analysed using two‐way anova of repeated‐measure design.Results  The CDJ in Egyptian sections ranged from 0 to 2.0 mm (mean ± SD = 0.9 ± 0.4 mm) on the mesial side of the canal and from 0.2 to 2.5 mm (mean ± SD = 1.0 ± 0.5 mm) on the distal aspect. In the Saudi sample, the CDJ ranged from 0.5 to 1.2 mm (mean ± SD = 0.8 ± 0.3 mm) on the mesial side and from 0.6 to 0.9 mm (mean ± SD = 0.7 ± 0.4 mm) on the distal side. The mesial and distal differences between Egyptian and Saudi premolars on the mesial and distal surface were statistically significant (P < 0.001).Conclusions  The location of the CDJ varied between the Egyptian and Saudi mandibular first premolars, indicating that this junction is not a fixed point in populations of different countries.
An evaluation of the usefulness of two endodontic case assessment forms by general dentists
Authors: Ree M. H. , Timmerman M. F. , Wesselink P. R. 
Published: July 2003

AbstractAim  To evaluate the use of two forms to assess the risks and difficulty of root‐canal treatment.Methodology  Two criterion‐based forms, containing 15 and 16 items, respectively, were distributed to 83 general dentists to evaluate the potential difficulty of root‐canal treatment. The participants were asked to assess the difficulty of 15 endodontic cases using the Dutch Endodontic Treatment Index (DETI) and the Endodontic Treatment Classification (ETC) forms. A questionnaire was also provided to evaluate the time needed to complete the two forms, their ease of use, the clarity and/or appropriateness of the criteria and any other comments. The outcomes of the assessment were compared with the assessment of each case as carried out by the authors.Results  The response rate was 53%. The DETI was an easy and rapid way to differentiate between uncomplicated and complicated cases. In 13 of the 15 cases, 88–100% of the dentists scored the cases in agreement with the authors. Use of the ETC form was more complicated, as a result of the larger number of variables. However, most respondents recognized the complicated cases, and 91% found the ETC form valuable to help in assessing the difficulty of endodontic cases.Conclusions  These two forms may help general practitioners to assess the difficulty of endodontic problems and to decide whether to treat the case or to refer it to a specialist.
Ultrasound real‐time imaging in the differential diagnosis of periapical lesions
Authors: Cotti E. , Campisi G. , Ambu R. , Dettori C. 
Published: July 2003

AbstractAim  To assess whether the use of real‐time ultrasound imaging (echography), together with the application of ‘Colour Power Doppler’, can help the differential diagnosis of periapical lesions based on their contents.Methodology  Eleven patients diagnosed with periapical lesions using conventional clinical and radiographic findings and who had been scheduled for endodontic surgery were examined using ultrasound imaging and Colour Power Doppler at the site of the lesions. Lesions were described in each case by an expert echographist, together with an endodontist, according to a scheme described previously. Information on the size of each lesion, its content and its vascular supply was gained and recorded by means of the ultrasound images; then, a tentative differential diagnosis between a cyst and a granuloma was made. The lesions obtained during endodontic surgery were processed and examined with a light microscope. The results from the biopsies were compared with the descriptions made with the ultrasound images.Results  The differential diagnoses between periapical granulomas and cystic lesions, which were based on the echograpic findings, were confirmed by the results of the histopathologic examination in all the 11 cases: four being granulomas and seven being cystic lesions.Conclusions  Ultrasound real‐time imaging is a technique that may help make a differential diagnosis between cysts and granulomas by revealing the nature of the content of a bony lesion. This technique may have further applications in the study of other lesions of the jaws.
Osteoblasts and MG‐63 osteosarcoma cells behave differently when in contact with ProRoot™ MTA and White MTA
Authors: Pérez A. L. , Spears R. , Gutmann J. L. , Opperman L. A. 
Published: July 2003

AbstractAim  To test the hypothesis that MG‐63 osteosarcoma cells and primary osteoblasts react differently to ProRoot™ MTA (mineral trioxide aggregate) and White MTA by: (i) investigating the attachment of primary osteoblasts and MG‐63 osteosarcoma cells to ProRoot™ MTA and White MTA; and (ii) comparing the osteogenic behaviour of both cell lines in contact with these endodontic materials.Methodology  Primary osteoblasts were harvested from foetal rat calvaria by sequential digestion and MG‐63 osteosarcoma cells were purchased. Cells were exposed to ProRoot™ MTA and White MTA prepared according to the manufacturer's instructions. All samples and controls were prepared in quadruplicate. After 6, 9 and 13 days exposure to MTA, the cells were fixed and prepared for SEM examination. In addition, both the cell types were grown to confluence and exposed to β‐glycerophosphate and dexamethasone to assess mineralized nodule formation as a function of osteogenic behaviour.Results  The number of cells on the surface of the culture dish and on top of the materials increased in all samples throughout the 3 time periods, except for White MTA where no primary osteoblasts were visible on top of the material by the end of 13 days. After exposing cells to differentiation medium nodules were observed in cultures of primary osteoblasts, but not of MG‐63 osteosarcoma cells.Conclusions  Under the conditions of this study, whilst primary osteoblasts initially bound to White MTA, they did not survive on the surface by the end of 13 days. Primary osteoblasts formed mineralized nodules when exposed to differentiation medium, whilst MG‐63 cells did not form nodules. As MG‐63 cells do not behave osteogenically by forming mineralized nodules, and primary osteoblasts are more sensitive than MG‐63 osteosarcoma cells to White MTA in cell culture, primary osteoblasts are more appropriate than MG‐63 cells for testing endodontic materials in cell culture.
Phylogeography of the northern hogsucker, Hypentelium nigricans (Teleostei: Cypriniformes): genetic evidence for the existence of the ancient Teays River
Authors: Berendzen Peter B. , Simons Andrew M. , Wood Robert M. 
Published: July 2003

AbstractAim  To assess the roles of dispersal and vicariance in shaping the present distribution and diversity within Hypentelium nigricans, the northern hogsucker (Teleostei: Cypriniformes).Location  Eastern United States.Methods  Parsimony analyses, Bayesian analyses, pairwise genetic divergence and mismatch plots are used to examine patterns of genetic variation across H. nigricans.Results  Species relationships within the genus Hypentelium were consistent with previous hypotheses. However, relationships between haplotypes within H. nigricans revealed two deeply divergent groups, a clade containing haplotypes from the New and Roanoke rivers (Atlantic Slope) plus Interior Highlands and upper Mississippi River and a clade containing haplotypes from the Eastern Highlands, previously glaciated regions of the Ohio and Wabash rivers, and the Amite and Homochitto rivers of south‐western Mississippi.Main conclusions  The phylogenetic history of Hypentelium was shaped by old vicariant events associated with erosion of the Blue Ridge and separation of the Mobile and Mississippi river basins. Within H. nigricans two clades existed prior to the Pleistocene; a widespread clade in the pre‐glacial Teays‐Mississippi River system and a clade in Cumberland and Tennessee rivers. Pleistocene events fragmented the Teays‐Mississippi fauna. Following the retreat of the glaciers H. nigricans dispersed northward into previously glaciated regions. These patterns are replicated in other clades of fishes and are consistent with some of the predictions of Mayden's (Systematic Zoology, 37, 329, 1988) pre‐Pleistocene vicariance hypothesis.
Mammals of south‐east Asian islands and their Late Pleistocene environments
Authors: Meijaard Erik 
Published: July 2003

AbstractAim  The environments that existed in south‐east Asian islands during the last glacial are poorly known, limiting our understanding of mammalian biogeography in the region. The objective of this research is to investigate the ecological characteristics of mammal faunas on small islands, and to see whether the habitat requirements of the species in those faunas can be used to deduct the vegetation types that existed on islands before becoming isolated by rising sea levels.Location  The maps presented here cover the small islands of tropical south‐east Asia, including the Burmese, Thai and Cambodian islands in the north, the islands off the coast of west Sumatra in the west, the islands around Java in the south, and the islands off the east coast of Borneo in the east, including the Philippine islands of Palawan and those in the Sulu Archipelago.Methods  The presence records of mammal species on 215 small islands in the region were compiled, and the habitat requirements for each of these species was assessed (species that had probably been introduced by humans were excluded from the analysis). For each island location (longitude and latitude), maximum altitude of the island, total area, depth to nearest land, distance to nearest island, and distance to nearest mainland were assessed. Geographical and statistical analyses were used to investigate patterns of mammalian habitat requirements.Results  The geographical analysis showed that forest‐dependent species, i.e. species that are only found in primary forest (lowland and mountainous), appear to be concentrated on islands off west Sumatra, in the Lingga and Riau Archipelagos, around Palawan, and around Bunguran Island; they are absent mostly from the islands of the Java Sea, those off the east coast of eastern Borneo, from most islands in the Sunda Strait, several islands in the northern South China Sea, and from all islands off the west coast of the Malay/Thai Peninsula and in the Gulf of Thailand. Species that generally occur outside primary forest, that is those in secondary forest, gardens, plantations and open areas mostly occurred on islands where the forest‐dependent species were absent. The statistical analysis showed that latitude and size of islands were important factors that determined the absence and presence of forest‐dependent species on small islands.Main conclusions  The data suggest that during the last glacial there were several areas in the Sundaic region that remained forest covered: west of Sumatra, north‐west of Borneo, the Malacca Straits and around Palawan. Other areas may have been covered by more open vegetation types like tree savanna, or open deciduous forest: on and to the east of the Malay/Thai Peninsula, the Java Sea area, including the Sunda Strait, and eastern Borneo.
Ectoparasites of terrestrial vertebrates inhabiting the Georgia Barrier Islands, USA: an inventory and preliminary biogeographical analysis
Authors: Wilson Nixon , Durden Lance A. 
Published: July 2003

AbstractAim  To document ectoparasitic arthropods of terrestrial vertebrates inhabiting barrier islands and to offer preliminary interpretations.Location  The coast of Georgia, USA, with most data presented for St Catherines, Sapelo, Jekyll, and Cumberland islands.Methods  Ectoparasites were collected and identified from hundreds of live‐trapped mammals, birds, and reptiles. Ticks and louse‐flies were also collected by dragging or flagging a white cloth through vegetation. Some ectoparasites were recovered from host nests or roosting sites. Literature records and specimen records from the US National Tick Collection supplemented these data.Results  Inventories of ectoparasite species recovered from vertebrates on each island are provided. Many new records and a small number of undescribed species are reported.Main conclusions  Compared with most ectoparasite faunas associated with the same host species on the adjacent mainland, ectoparasite species diversity on the barrier islands is depauperate. Possible reasons for this phenomenon are discussed including ecological, geological, and vicariant factors. Tick faunas do not appear to be depauperate on the islands probably because immature stages attach to visiting or migrating birds. Some host‐ectoparasite associations that we recorded are atypical for mainland faunas. This trend has also been recorded in some previous surveys of insular ectoparasites and may be related to vacant ectoparasite niches on some islands.
Spatial similarity of urban bird communities: a multiscale approach
Authors: Jokimäki Jukka , Kaisanlahti‐Jokimäki Marja‐Liisa 
Published: July 2003

AbstractAim  Human land use, especially urbanization, might homogenize the world's biota. The objective of this study is to find out if urbanization homogenizes wintering bird communities, and if habitat type affects the spatial variation of urban bird communities across spatial scales.Location  We compared the quantitative similarity of winter bird communities between town centres, apartment block areas and single‐family house areas across regional and local scales in five towns in northern Finland.Methods  The wintering birds were surveyed using a single‐visit study plot (30 ha) method in January and February 2001. The validity of single‐visit and single‐year data was confirmed by using data from several‐visit surveys and multi‐year data set. The level of urbanization was measured according to the number of inhabitants and general structure of the habitat.Results  Temporal variability in species richness and total number of individuals was low, both between winters and within winter. Bird community similarity between different habitat types within a single town was about the same as that in similar habitats in different towns. At the regional scale, bird community similarity between town centres (30%) was lower than between areas of apartment blocks (54%) or between areas of single‐family houses (54%). We detected a threshold point between towns of 35,000 and 105,000 inhabitants and between town sizes of 5.0–8.5 km in diameter where human impact causes marked changes in bird community structure. At the local scale, bird community similarity level between apartment block areas (49%) and single‐family house areas (62%) were about the same. Passer domesticus, Parus major and Pica pica dominated the bird communities in residential areas. Different habitat factors affected bird species abundances on the local and regional scales.Conclusions  Urbanization cannot be seen as a process that monotonically increases the similarity of bird communities. Our results indicate that the similarity between urban bird communities is dependent on the size of the town, location of the study site within the town and especially the local habitat structure. Because different habitat factors affected bird species abundances, it is difficult to extrapolate bird–habitat relationships derived from one scale to other scales. In wintertime, single‐family house areas are important biodiversity hotspots in cities. Therefore, it is especially important to understand the factors affecting the occurrence of birds in the single‐family house area in order to maintain or even increase diversity on winter birds in other urban habitats.