bluuebunny/crossref_metadata_2025_split huggingface dataset:
DNA‐PK inhibitor wortmannin enhances DNA damage induced by bleomycin in V79 Chinese hamster cells
Authors: Oliveira Nuno G. , Castro Matilde , Rodrigues António S. , Gil Octávia M. , Toscano‐Rico José M. , Rueff José 
Published: September 2002

AbstractThe fungal metabolite wortmannin (WM) is a potent and irreversible inhibitor of the enzyme DNA‐dependent protein kinase (DNA‐PK), a nuclear serine‐threonine kinase, member of the phosphaditylinositol‐3 kinase related kinase family. WM has been used in the last few years as a promising radiosensitizer mainly throughout cell survival experiments. However, few studies have addressed the role of DNA‐PK inhibition in the repair of DNA lesions generated by antitumor agents. Bleomycin (BLM) is an antitumor agent used in the treatment of various neoplasia with a unique genotoxicity profile that mimics the ionizing radiation effects. In this study, we evaluated the effect of different concentrations of WM on the DNA damage induced by BLM. The cytokinesis‐block micronucleus assay (CBMN) in V79 Chinese hamster cells was used as the end‐point. WM significantly increased the frequency of micronucleated cells (%MNBN) by about 2.2‐fold, the number of micronuclei per binucleated cell (MN/BN) by about 2.4‐fold, and also changed the pattern of the distribution of micronuclei induced by BLM. The frequency of micronucleated cells with 2 MN per cell and with ≥3 MN per cell increased, whereas the frequency of micronucleated cells with 1 MN per cell decreased. WM was not genotoxic but decreased cell proliferation as assessed by the frequency of binucleated cells. Our results show that WM clearly enhances the efficacy of BLM in terms of DNA damage inflicted and therefore reinforces its use as a chemosensitizer. Teratogenesis Carcinog. Mutagen. 22:343–351, 2002. © 2002 Wiley‐Liss, Inc.
Inhibitory effects of ascorbic acid and folinic acid on chromosome aberrations induced by pyrimethamine in vitro
Authors: Egel Çiĝdem , Bilaloĝlu Rahmi , Aydemir Nilüfer 
Published: September 2002

AbstractIn this study, the anticlastogenic effects of ascorbic acid and the protective effect of folinic acid against the formation of chromosomal aberrations in humans by pyrimethamine were investigated. Pyrimethamine is a folic acid antagonist used for the treatment of malaria and toxoplasmosis. In this study, 18 different healthy people, who do not drink alcohol and are non‐smokers, were chosen as an experimental group; 0.025 mg/ml pyrimethamine was given to the lymphocyte culture, which had been prepared with the peripheral blood taken from this group. After that each of the following doses were given to the same culture: 20, 40, and 80 mM of ascorbic acid and 25, 50, and 100 mM of folinic acid. The results of the cytogenetic evaluation showed that the aberrations due to pyrimethamine in the chromosomes were reduced by ascorbic acid and folinic acid significantly, depending on the given dose. Teratogenesis Carcinog. Mutagen. 22:353–362, 2002. © 2002 Wiley‐Liss, Inc.
Genetic polymorphisms in the cytochrome P450 1A1, glutathione S‐transferase M1 and T1, and susceptibility to colon cancer
Authors: Ye Zheng , Parry James M. 
Published: September 2002

AbstractSeveral polymorphic cytochrome P‐450 and glutathione S‐transferase (GST) enzymes are involved in the activation and detoxification of many potential carcinogens and may therefore be important in susceptibility to cancer induction. CYP1A1 MspI, GSTM1, and GSTT1 are polymorphic enzymes and some alleles have been correlated with an increased risk of developing some cancers. In the present study, we examined possible associations between genetic polymorphisms of CYP1A1 MspI, GSTM1, and GSTT1 and colon cancer in a United Kingdom population. An excess of CYP1A1 MspI, and GSTM1 null genotypes was observed amongst colon cancer patients, although this did not reach the level of statistical significance. We found no significant increase in the risk of colon cancer for either CYP1A1 MspI (OR = 1.39; 95%CI: 0.46–4.21) or GSTM1 null (OR = 1.41; 95%CI: 0.76–3.01) genotypes. Individuals with GSTT1 null genotype had no association with colon cancer (OR = 0.42; 95%CI: 0.09–2.02). No significant association was observed in the site of colon cancer (proximal vs. distal). This study suggests that the polymorphisms of CYP1A1 MspI, GSTM1, and GSTT1 are not associated with a significant risk of developing colon cancer in a United Kingdom population. Teratogenesis Carcinog. Mutagen. 22:385–392, 2002. © 2002 Wiley‐Liss, Inc.
Brazil and Mexico—Partners in sowing a free trade area of the Americas
Authors: Gouvea Raul 
Published: September 2002

AbstractThe second half of 2000 brought renewed interest to the Free Trade Agreement of the Americas (FTAA).

This hemispheric economic integration initiative presents numerous opportunities and challenges for each of the

34 countries involved in unifying markets across the Americas. The North American Free Trade Agreement

(NAFTA) and Mercosur, the region's two largest trading blocs, play a vital role in any attempt to

integrate Latin American markets. Integration under Mercosur has strengthened the position of member

countries—especially Brazil, which is a choice location for foreign direct investment and has realized a

significant growth in extra‐Mercosur trade. The newly elected Mexican president, Vicente Fox, has

demonstrated a strong desire to bring Mexico to the forefront of hemispheric trade negotiations and brings a new

dynamic to integration of Latin American markets and to the FTAA initiative. This article elaborates on the role

of the two largest Latin American economies and the United States in the creation and solidification of a

hemispheric trading bloc in the Americas. © 2002 Wiley Periodicals, Inc.
The relationship between Arab values and work beliefs: An exploratory examination
Authors: Robertson Christopher J. , Al‐Khatib Jamal A. , Al‐Habib Mohammed 
Published: September 2002

AbstractIn this study, 365 employees from three Middle Eastern countries (Saudi Arabia, Kuwait, and Oman) are

queried about their cultural values and work‐related beliefs. This analysis is unique both in its sample

and its focus on the relationship between individual cultural values and beliefs about work. Results suggest that

the cultural value dimensions individualism (p < .001) and masculinity (p < .001) are

related to both an individual's beliefs about organizational commitment and work ethic. Additional findings

reveal patterns between cultural values and humanistic and political beliefs. Future research directions and

managerial implications are also discussed. © 2002 Wiley Periodicals, Inc.
A single FKS homologue in Yarrowia lipolytica is essential for viability
Authors: León Maela , Sentandreu Rafael , Zueco Jesús 
Published: September 2002

AbstractThe synthesis of β‐1,3‐glucan, the structural component of the yeast cell wall which gives shape to the cell, occurs at the plasma membrane and is the result of the activity of at least a two‐component complex. Fks1p is the catalytic subunit directly responsible for the synthesis of β‐1,3‐glucan, whilst the second subunit, Rho1p, has a GTP‐dependent regulatory role. FKS1 has been characterized in Saccharomyces cerevisiae, where its function is at least partially redundant with that of FKS2/GSC2. FKS homologues have also been identified in several other fungal species, including Candida albicans, Schizosaccharomyces pombe, Aspergillus nidulans, Cryptococcus neoformans and Paracoccidiodes brasiliensis. In this work, we have used degenerate oligonucleotides derived from the conserved regions of Fks1ps to isolate the possible FKS homologue genes of the strictly aerobic non‐conventional yeast Yarrowia lipolytica. Using this approach, we have isolated a single FKS homologue which we have named YlFKS1; this codes a 1961 amino acid protein that shows a high degree of homology with other Fksps. Expression analysis of YlFKS1 under different conditions affecting the cell wall did not reveal significant differences. Finally, attempts to obtain a Y. lipolytica strain containing a disrupted YlFKS1 allele failed, despite having used two different techniques. Taken together, these results suggest that, unlike S. cerevisiae, YlFKS1 is the only FKS1 homologue in Y. lipolytica and is essential for growth. Copyright © 2002 John Wiley & Sons, Ltd.
HXT5 expression is determined by growth rates in Saccharomyces cerevisiae
Authors: Verwaal René , Paalman Johannes W. G. , Hogenkamp Astrid , Verkleij Arie J. , Verrips C. Theo , Boonstra Johannes 
Published: September 2002

AbstractIn the yeast Saccharomyces cerevisiae, hexose transporter (Hxt) proteins transport glucose across the plasma membrane. The Hxt proteins are encoded by a multigene family with 20 members, of which Hxt1–4p and Hxt6–7p are the major hexose transporters. The remaining Hxt proteins have other or unknown functions. In this study, expression of HXT5 under different experimental set‐ups is determined. In glucose‐grown batch cultures, HXT5 is expressed prior to glucose depletion. Independent of the carbon source used in batch cultures, HXT5 is expressed after 24 h of growth and during growth on ethanol or glycerol, which indicates that growth on glucose is not necessary for expression of HXT5. Increasing the temperature or osmolarity of the growth medium also induces expression of HXT5. In fed‐batch cultures, expression of HXT5 is only observed at low glucose consumption rates, independent of the extracellular glucose concentration. The only common parameter in these experiments is that an increase of HXT5 expression is accompanied by a decrease of the growth rate of cells. To determine whether HXT5 expression is determined by the growth rate, cells were grown in a nitrogen‐limited continuous culture, which enables modulation of only the growth rate of cells. Indeed, HXT5 is expressed only at low dilution rates. Therefore, our results indicate that expression of HXT5 is regulated by growth rates of cells, rather than by extracellular glucose concentrations, as is the case for the major HXTs. A possible function for Hxt5p and factors responsible for increased expression of HXT5 upon low growth rates is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
A comparison of digital and film radiography in Dutch dental practices assessed by questionnaire.
Authors: Berkhout W E R , Sanderink G C H , Van der Stelt P F 
Published: September 2002

OBJECTIVES The purpose of this study was to assess the experiences of general dental practitioners (GDPs) with solid-state and storage phosphor digital sensors compared to film. METHODS In a mail survey 578 questionnaires were sent to Dutch GDPs who were users of digital X-ray detectors and film. The questionnaire requested demographic data, information about the digital system used and the user-friendliness of the X-ray detector system. In the analysis of the data these variables were related to the type of system used and also to the demographic data. The data were analysed using descriptive statistics, variance-analysis (One-Way ANOVA) and nonparametric tests (Kruskal-Wallis, Mann-Whitney and Wilcoxon) (SPSS 9.0). RESULTS Four hundred and twenty-four questionnaires were returned (overall response rate 73%). The user-friendliness of the handling of the different systems before exposing the radiograph is better for conventional film, whereas the handling after exposing the radiograph favoured the digital X-ray detector systems. CONCLUSIONS The user-friendliness was best for film pre-exposure and digital sensors post-exposure.
Odontogenic myxomas in the Hong Kong Chinese: clinico-radiological presentation and systematic review.
Authors: MacDonald-Jankowski D S , Yeung R , Lee K M , Li T K L 
Published: September 2002

AIM The aim of this study was to determine the clinical and radiological presentation on plain films of central odontogenic myxomas (OM) in the Hong Kong Chinese and compare them to other reported series by a systematic review (SR). METHODS The study had two elements, that of a complete series of all OMs presenting at a major Chinese maxillofacial surgical unit and a SR. The files of the Department of Oral and Maxillofacial Surgery of the University of Hong Kong between 1989 and 2000 were reviewed for OM cases. The relevant literature was identified by electronic databases, review of citation lists and handsearching of key journals. The principal selection criterion was that the study should represent a complete collection of cases. RESULTS The SR revealed that only a quarter of the reports provided any quantitative radiological details. Just under half of the included reports provided the relative period prevalence of OMs compared to other odontogenic tumours, but these reports almost completely excluded consideration not only of the radiology but also specific clinical details. Furthermore, they did not report of recurrence data, an important feature of the OM. Most of the most recent reports were concerned with relative period prevalence. The relative period prevalence and 'number of OMs per hospital per year' of studies separated by two or more decades in Hong Kong and Nigeria indicate an increase in the number of lesions diagnosed as OMs. The 10 Hong Kong cases were broadly consistent with the predilections for females and the mandible of other reports. The mean age at first presentation in the present report is 36.9, older than the other reports. Most lesions are large, affecting both posterior and anterior quadrants. They appear to be larger than those in many other reports. Two of the OMs are accompanied by histories of recent rapid growth. Tooth displacement and root resorption are more frequently observed in OMs in the present study. Although all OMs in the present study are still being followed up after surgery, none have recurred. CONCLUSION Although the presentation of larger lesions in the older Chinese could in part be explained by attitudes rooted in traditional medicine in spite of the widespread availability of modern medical care in Hong Kong, there is a history of recent rapid growth in at least two cases. An emphasis by recent reports on the OMs' relative period prevalence of concurrent odontogenic lesions, has omitted recording the radiology and the specific clinical details usually required for diagnosis.,
Accuracy of tuned aperture computed tomography in the diagnosis of radicular fractures in non-restored maxillary anterior teeth--an in vitro study.
Authors: Nair M K , Nair U P , Gröndahl H-G , Webber R L 
Published: September 2002

OBJECTIVES This study compared the accuracy of three radiographic imaging modalities for the detection of artificially induced radicular fractures on maxillary anterior teeth. METHODS Fractures were induced in 28 of 54 maxillary incisors in 15 cadaver specimens using a distally directed force. Radiographs evaluated included conventional two-dimensional direct digital radiographs (DDI), unprocessed Tuned Aperture Computed Tomography (TACT-U) and iteratively restored TACT (TACT-IR). Eight observers recorded their findings using a five-point confidence-rating scale. Receiver Operating Characteristic (ROC) analyses were done, followed by ANOVA to test for significant effects of observers, imaging modality and fracture location. Post hoc tests were carried out in instances where ANOVA indicated significance. RESULTS The areas under the ROC-curves (A(z)) were, respectively: DDI: 0.53; TACT-U: 0.83 and TACT-IR: 0.97. TACT-IR and TACT-U performed significantly better than DDI (P < 0.001) with TACT-IR providing a higher detection accuracy than TACT-U (P < 0.033). A difference in detection accuracy was also noted based on fracture location (P < 0.001). Tukey's post hoc analyses revealed that fractures extending beyond the middle third of the root were more accurately detected. Inter-observer agreement was 0.68, and intra-examiner agreement, 0.87 (kappa analysis). CONCLUSIONS TACT performed significantly better than direct digital images in detecting trauma-induced radicular fractures in unrestored, maxillary anterior teeth.
Utility of frequency-selective fat saturation T2-weighted MR images for the detection of joint effusion in the temporomandibular joint.
Authors: Tanaka T , Morimoto Y , Masumi S , Tominaga K , Ohba T 
Published: September 2002

OBJECTIVES To evaluate joint effusion in the temporomandibular joint (TMJ) using frequency-selective fat saturation (FS) T2-weighted images and assess this technique. To investigate whether bone marrow abnormalities and magnetic resonance imaging (MRI) findings of internal derangement may be linked to joint effusion in the TMJ in patients with pain. METHODS TMJ effusion was sought on FS T2-weighted images and conventional T2-weighted images in 400 joints from 200 patients with TMJ-related pain. Self-reported pain records were obtained from patients immediately before MRI and images assessed by the amount of TMJ fluid graded bilaterally using reference films by two radiologists. Other parameters recorded included disk displacement categories and condyle marrow abnormalities. The association between the recorded parameters and TMJ effusion judged by FS-sequences or conventional sequences was analysed using chi-square and Kappa tests. RESULTS The detection rate of TMJ effusion by FS-sequences was significantly greater than by conventional methods, and the results showed a significant relationship between MRI interpretation of TMJ effusion using FS-sequences or conventional methods and the presence of pain. The correlation between TMJ effusion on FS-sequences and pain was significantly stronger than the conventional method. Kappa test indicated good agreement between pain and MRI TMJ effusion by FS-sequences (kappa = 0.66), but not by conventional sequences (kappa = 0.56). The other parameters showed a similar trend for TMJ-related pain. CONCLUSIONS FS T2-weighted imaging is useful for detection of TMJ effusion, without known causes and confirms the importance of TMJ effusion as an indicator in patients with TMJ-related pain, bone abnormalities, and disk displacement.
A new device for measuring density of jaw bones.
Authors: Yang J , Chiou R , Ruprecht A , Vicario J , MacPhail L A , Rams T E 
Published: September 2002

OBJECTIVES The purpose of this project was to develop a lightweight, simple device to evaluate alveolar process bone density using normal intraoral and extraoral imaging procedures. METHODS A simple lightweight device was constructed using barium sulfate as the major radiopaque component. The 5 x 32 x 12 mm(3) resin block has eight segments with known densities ranging from 1.304 (g/cm(3)) to 1.982 (g/cm(3)). The device was integrated into an XCP unit for standard intraoral radiographs and placed between the jaws for computer aided tomographic imaging. The relationship between the device segment densities and the optical densities of the exposed film was plotted. RESULTS A linear inverse relationship was found between the device segment densities and optical densities when segment densities were between 1.304 (g/cm(3)) to 1.882 (g/cm(3)). However, the relationship was non-linear for segment densities above 1.882 (g/cm(3)). CONCLUSIONS Normal human bone density is 1.85 (g/cm(3)), and this densitometer is useful for determination of material densities from 1.304 (g/cm(3)) to 1.882 (g/cm(3)). The device may be useful for precise bone density assessment.
Radiographic practices of dentists undertaking endodontics in New Zealand.
Authors: Chandler N P , Koshy S 
Published: September 2002

OBJECTIVES To determine the radiographic practices of New Zealand dentists undertaking root canal treatment, and to investigate the relationship between radiographic practices and educational and clinical factors. METHODS A questionnaire was sent to all 1200 general dental practitioners and five specialist endodontists in New Zealand. Data were subjected to descriptive and analytical statistics. RESULTS The response rate was 79%. The mean number of root canal treatments done by general dentists in the previous 12 months was 103, and for the specialists 938. Pre-operative views were taken by 57.1% of respondents all the time and by 34.8% in most cases. The long cone paralleling and bisecting angle techniques were in regular use by similar numbers of respondents, and over one half of the practitioners regularly used film holders and electronic apex locators. Working length films were taken by 67% of practitioners all the time and by 18% in most cases. One-quarter of practitioners took a master point view all the time, and 15% did this for most cases. Almost 65% always took a film of the completed root filling and 21% did for most cases. Twenty-three per cent of practitioners did not follow up their work. CONCLUSIONS The majority of respondents used radiographs pre-operatively, for working length assessment and to assess the final root filling. There was a general improvement in radiographic practices compared with data from a previous national survey held in 1980.
Lingual and buccal mandibular bone depressions: a review based on 583 cases from a world-wide literature survey, including 69 new cases from Japan.
Authors: Philipsen H P , Takata T , Reichart P A , Sato S , Suei Y 
Published: September 2002

OBJECTIVES To review present knowledge of so-called lingual and buccal mandibular bone depressions (n = 583) based on studies of 247 contemporary and 267 archaeological cases from a world-wide literature survey in addition to 69 new cases from Japan. METHODS The 69 cases from Japan were retrieved through examination of 42,600 consecutive panoramic radiographs. RESULTS Bone depressions can be divided into four topographical variants: (1) lingual anterior mandibular body (incisor-canine- premolar area) above the mylohyoid muscle; (2) posterior to the mandibular angle-first permanent molar area, below the mandibular canal, and a third located to the ascending, lingual mandibular ramus, posterior to the lingual foramen, just below the neck of the condyle. An excessively rare fourth variant is located to the buccal aspects of the ascending mandibular ramus. CONCLUSIONS The present concept favours that all variants have a common origin: a hyperplastic/hypertrophic lobe (or aberrant lobe) of the sublingual, submandibular or parotid salivary gland, exerting pressure upon the cortex of the mandible by the respective gland, leading to focal atrophy or resorption of the bone. The bone depressions take years to develop, appearing radiographically not until the 5th to 6th decades.