bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thiol groups and reduced acidogenicity of dental plaque in the presence of metal ions in vivo
Authors: OPPERMANN RUI VICENTE , RØLLA GUNNAR , JOHANSEN JAN ROLF , ASSEV SYNNØVE 
Published: October 2007

Abstract –Metal ions are known to influence the cariogenicity of dental plaque. Inhibition of acid metabolism in plaque may be of importance in this respect. Metal ions inhibit the acidogenicity of dental plaque to a different extent and it has been suggested that an enzyme inhibition based on oxidation of thiol groups may explain this observation. The aim of the present study was to evaluate the significance of oxidation of thiol groups in the inhibition of acid production in plaque by silver, tin and zinc salts. Nine subjects with 3‐d sucrose induced plaque received topical applications of the metal ions. Cysteine or gilutathione, which are known to reverse thiol oxidations, were then applied in one side of the mouth. Plaque pH measurements, in the presence of sucrose, were performed prior to and up to 2 h after treatment. The results showed that the acid production inhibited by the metal ions was reactivated by cysteine or glutathione. Iodoacetamide and ρ‐chloromercuribenzoate were also shown to inhibit acid formation in dental plaque. The high affinity silver, tin and zinc have for SH groups, the observed inhibitory effect of these metals, the reactivation of the metabolism by monothiols and the fact that organic sulfhydryl reagents inhibit acid formation in plaque indicate that oxidation of thiol groups may be the mechanism by which these metals exert their effect.
Role of sucrose in plaque formation
Authors: RÖLLA GUNNAR , SCHEIE ANNE AAMDAL , CIARDI JOSEPH E. 
Published: October 2007

Abstract –Results are presented which support the concept that the bacterial enzyme glucosyltransferase (GTF) plays a crucial role in sucrose induced plaque formation. GTF was shown to adhere strongly to anionic, hydrophobic and polysaccharide solid materials, and to be able to produce glucans in the adsorbed state. It appears conceivable that GTF adsorb to teeth and produce glucans. Glucan chains on (he surface of the bacteria and glucans on the tooth surfaces interact (pack) and form a strong binding mechanism. The rigid α1,3 linked glucans produced by Streptococcus mutans are particularly suited for interaction of this kind. This mechanism could account for sucrose‐induced binding of bacteria to enamel, pellicle covered enamel and preformed plaque. S. mutans would adhere particularly strongly to tooth surfaces in the presence of sucrose, according to this model.
Oligosaccharides obtained by partial hydrolysis of lipopolysaccharides from Leptotrichia buccalis
Authors: BIRKELAND NILS KARE , HOFSTAD TOR 
Published: October 2007

Abstract –Lipopolysaccharides (LPS) from Leptotrichia buccalis, strains LI 1, ATCG 14201 and ATCG 19616 were partially degraded with 1 % acetic acid. The acid soluble polysaccharides were subjected to gel filtration. These experiments showed that the carbohydrate moiety of LPS from ATGC 14201 and ATCG 19616 were similar, consisting ofa core oligosaccharide unsubstituted by 0‐side chains containing galactose, glucose and D‐glycero‐D‐manno‐heptose as neutral sugars. The core analogous fraction isolated from LI 1 LPS contained the same three neutral sugars, but in different ratios.
Galvanic currents between dental alloys in vitro
Authors: ARVIDSON KRISTINA , JOHANSSON E. GUNNAR 
Published: October 2007

Abstract –The galvanic current densities between gold, amalgam and cobalt‐chromium, three different classes of dental alloys, were determined in vitro in artificial saliva kept at 35°C. The maximum current density of 200 μA/drn2was obtained between the conventional amalgam and a type III gold alloy. Galvanic currents of lesser magnitude could also be measured between amalgams high in copper and the other alloys. No measurable current densities were obtained between gold alloys and between gold and cobalt‐chromium alloy with the exception of a casting and a solder gold alloy commonly used in combination.
Replica techniques for in vivo studies of tooth surfaces and prosthetic materials
Authors: EKFELDT ANDERS , FLÖYSTRAND FINN , ÖILO GUDBRAND 
Published: October 2007

Abstract –In order to obtain a replica technique suitable for a complete or segments of a dental arch two different impression materials were combined with two epoxy resin model materials. The models were examined and photographed in an optical microscope and a scanning electron microscope. No systematic differences were found between the used combinations of materials except a tendency towards greater contraction of one of the model materials. The A‐silicone impression materials combined with one of the epoxy resin material seemed to be the easiest to handle and to give the best models.
Effect of three dentin adhesives on marginal adaptation of two light‐cured composites
Authors: HANSEN ERIK KEITH 
Published: October 2007

Abstract –The marginal adaptation of two light‐cured composites, Silux and P‐30, was tested in butt‐joint dentin cavities prepared in extracted human teeth. The cavity diameter ranged from 1.8 mm to 6.3 mm. Only minor differences were found between the marginal contraction gap of Silux and P‐30 when used without previous application of a dentin adhesive. The lightcured Scotchbond proved to be as effective as GLUMA in reducing the contraction gaps of Silux providing the smear‐layer was partly removed, the adhesive polymerized for 50 s and finally wetted with Silux Enamel Bond prior to application of Silux. Both adhesives had markedly less effect on the contraction gaps of the highly filled P‐30.
Phylogenetic diversity of bacteria isolates from the Qinghai-Tibet Plateau permafrost region
Authors: Zhang Gaosen , Niu Fujun , Ma Xiaojun , Liu Wei , Dong Maoxing , Feng Huyuan , An Lizhe , Cheng Guodong 
Published: September 2007

The Qinghai-Tibet Plateau in east Asia is a unique and important permafrost environment. However, its microbiology remains largely unexplored to date. In this study, sediment samples were collected from the Qinghai-Tibet Plateau permafrost region, bacteria isolation procedures were performed 8 times, and the samples incubated at 4 °C for nearly 3 months. The number of colony forming units (cfu) ranged from 0 to 107/(g dry soil). The quantity of culturable bacteria grew exponentially within the first few weeks, and then slowed gradually to a plateau. Phylogenetic analyses indicated that all the isolates fell into 6 categories: high G+C Gram-positive bacteria, low G+C Gram-positive bacteria, α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, and Cytophaga–Flavobacterium–Bacteroides group bacteria. The isolates belong to 19 genera, but the genera Arthrobacter and Pseudomonas were predominant. With the increase in incubation time, the isolated populations changed in terms of both species and their respective quantities. Of the 33 analyzed isolates, 9 isolates related to 8 genera might be new taxa. These results suggest that the Qinghai-Tibet Plateau permafrost region is a specific ecologic niche that accommodates an original microbial assemblage.
Microbial surfactant activities from a petrochemical landfarm in a humid tropical region of Brazil
Authors: Maciel Bianca Mendes , Dias João Carlos Teixeira , Freire dos Santos Ana Cácia , Argôlo Filho Ronaldo Costa , Fontana Renato , Loguercio Leandro Lopes , Rezende Rachel Passos 
Published: September 2007

The goal of this study was to assess the presence and surfactant potential of naturally occurring microbes from a tropical soil with petrochemical contamination. Microorganisms in a soil sample from a Brazilian landfarm were isolated and grown on petroleum as the sole carbon source. Of 60 isolates screened for petroleum-based growth, 7 demonstrated surfactant activities by the drop–collapse methodology over various types of oils. From their growth profiles in liquid culture during 132 h, all had their first detection of surfactant activity after 96 h. Little is currently known about biosurfactant-producing microorganisms in tropical environments contaminated by hydrophobic compounds, and the search for them is essential for bioremediation and for oil recovery enhanced by microbes. Our results indicate that different petroleum-grown microorganisms showing surfactant activity can be recovered from landfarm soil in a tropical environment.
Murine immunomodulation of IL-10 and IL-12 induced by new isolates from avian type 2 Lactobacillus acidophilus
Authors: Bleau Christian , Savard Roland , Lamontagne Lucie 
Published: September 2007

Several bacterial and immunogenic factors are involved in the host response to probiotic strains of Lactobacillus . Here, we report the isolation of new intestinal lactobacilli from chicken, with different immunomodulating properties on lymphoid cells from SJL and C57BL/6 mice. Analysis of biochemical markers in the Lactobacillus acidophilus CBA4P, CBA3P, and TPA3P isolates reveal that these bacterial isolates belong to the type 2 prototype, although they differ from each other. The effect of conditioned media (CM) from SJL- and C57BL/6-derived peritoneal macrophages incubated with the 3 sonicated bacterial isolates from chicken, as well as with Lactobacillus rhamnosus 9595, Escherichia coli lipopolysaccharide, or Staphylococcus aureus peptidoglycan were compared. Our results show that the CM of macrophages from C57BL/6 and SJL mice treated with the CBA4P isolate stimulated syngeneic splenic lymphocytes at a level similar to the one induced with CM from peptidoglycan-stimulated macrophages. In contrast, the CM from TPA3P- and CBA3P-treated macrophages promoted low or no stimulation of lymphoid cells. Incubation of splenic cells with CM from macrophages treated with L. rhamnosus or TPA3P led to a relative decrease in the percentages of splenic CD4+ T cells, whereas the relative percentages of B cells increased. The CBA4P and CBA3P isolates induced higher levels of gamma interferon when compared with the TPA3P isolate. The effects of the lactobacilli isolates differed according to the mouse strain used but correlated with the production of macrophagic tumor necrosis factor alpha and interleukins 6, 10, and 12 and with the modulation of the p38 mitogen-activated protein kinase (MAPK). Taken together, these results indicate that the immunomodulating properties of the new L. acidophilus isolates depend on their capacity to induce production of interleukins 10 and 12 by macrophages, which is under genetic control and depends on the p38 MAPK pathway.
Thermoregulation in two free-ranging subtropical insectivorous bat species: Scotophilus species (Vespertilionidae)
Authors: Jacobs D.S. , Kelly E.J. , Mason M. , Stoffberg S. 
Published: September 2007

Little is known about the thermal regulatory behaviour of free-ranging subtropical bats. We studied torpor use in two free-ranging subtropical sibling species of insectivorous bat, Scotophilus dinganii (A. Smith, 1833) and Scotophilus mhlanganii , during the austral autumn. All S. dinganii (mass 28.9 ± 2.6 g (mean ± SD)) roosted in buildings, whereas all S. mhlanganii (28.0 ± 0.4 g) roosted in the foliage of trees or in a tree cavity. Contrary to what has been seen in other subtropical species, both Scotophilus species used only one bout of torpor per day. Bats entered torpor 2 h after returning from foraging and aroused passively as the roost was heated by the sun the following day. There was a negative correlation between duration of foraging and duration of torpor, probably because bats that foraged longer had less time for torpor. Despite physical differences between roosts, foliage and building roosts appeared equally thermally labile, resulting in torpor bouts of similar depth and duration between individuals of the two species that used such roosts. Cavity-roosting female S. mhlanganii, on the other hand, used torpor bouts that were longer and shallower than those used by its female conspecifics in foliage roosts and female S. dinganii in buildings. Thus, thermal regulatory behaviour was determined more by the type of roost used than by interspecific differences in physiology.
Efficient identification of uncongested internet links for topology downscaling
Authors: Papadopoulos Fragkiskos , Psounis Konstantinos 
Published: September 2007

It has been recently suggested that uncongested links could be completely ignored when evaluating Internet's performance. In particular, based on the observation that only the congested links along the path of each flow introduce sizable queueing delays and dependencies among flows, it has been shown that one can infer the performance of the larger Internet by creating and observing a suitably scaled-down replica, consisting of the congested links only. Given that the majority of Internet links are uncongested, it has been demonstrated that this approach can be used to greatly simplify and expedite performance prediction.
However, an important open problem, directly related to the practicability of such an approach, is whether there exist efficient and scalable ways for identifying uncongested links, in large and complex Internet-like networks. Of course, such a question is not only very important for scaling down Internet's topology, but also in many other contexts, e.g. such as in traffic engineering and capacity planning.
In this paper we present simple rules that can be used to efficiently identify uncongested Internet links. In particular, we first identify scenarios under which one can easily deduce whether a link is uncongested by inspecting the network topology. Then, we identify scenarios in which this is not possible, and propose an efficient methodology, based on the large deviations theory and flow-level statistics, to approximate the queue length distribution,and in turn, to deduce the congestion level of a link. We also demonstrate how simple commonly used metrics, such as the link utilization, can be quite misleading in classifying an Internet link.
SND1, a Component of RNA-Induced Silencing Complex, Is Up-regulated in Human Colon Cancers and Implicated in Early Stage Colon Carcinogenesis
Authors: Tsuchiya Naoto , Ochiai Masako , Nakashima Katsuhiko , Ubagai Tsuneyuki , Sugimura Takashi , Nakagama Hitoshi 
Published: October 2007

Abstract
Colon cancers have been shown to develop after accumulation of multiple genetic and epigenetic alterations with changes in global gene expression profiles, contributing to the establishment of widely diverse phenotypes. Transcriptional and posttranscriptional regulation of gene expression by small RNA species, such as the small interfering RNA and microRNA and the RNA-induced silencing complex (RISC), is currently drawing major interest with regard to cancer development. SND1, also called Tudor-SN and p100 and recently reported to be a component of RISC, is among the list of highly expressed genes in human colon cancers. In the present study, we showed remarkable up-regulation of SND1 mRNA in human colon cancer tissues, even in early-stage lesions, and also in colon cancer cell lines. When mouse Snd1 was stably overexpressed in IEC6 rat intestinal epithelial cells, contact inhibition was lost and cell growth was promoted, even after the cells became confluent. Intriguingly, IEC6 cells with high levels of Snd1 also showed an altered distribution of E-cadherin from the cell membrane to the cytoplasm, suggesting loss of cellular polarity. Furthermore, the adenomatous polyposis coli (Apc) protein was coincidentally down-regulated, with no significant changes in the Apc mRNA level. Immunohistochemical analysis using chemically induced colonic lesions developed in rats revealed overexpression of Snd1 not only in colon cancers but also in aberrant crypt foci, putative precancerous lesions of the colon. Up-regulation of SND1 may thus occur at a very early stage in colon carcinogenesis and contribute to the posttranscriptional regulation of key players in colon cancer development, including APC and β-catenin. [Cancer Res 2007;67(19):9568–76]
Epidermal Growth Factor Receptor Cooperates with Signal Transducer and Activator of Transcription 3 to Induce Epithelial-Mesenchymal Transition in Cancer Cells via Up-regulation of TWIST Gene Expression
Authors: Lo Hui-Wen , Hsu Sheng-Chieh , Xia Weiya , Cao Xinyu , Shih Jin-Yuan , Wei Yongkun , Abbruzzese James L. , Hortobagyi Gabriel N. , Hung Mien-Chie 
Published: October 2007

Abstract
Aberrant epidermal growth factor receptor (EGFR) signaling is a major cause of tumor progression and metastasis; the underlying mechanisms, however, are not well understood. In particular, it remains elusive whether deregulated EGFR pathway is involved in epithelial-mesenchymal transition (EMT), an early event that occurs during metastasis of cancers of an epithelial origin. Here, we show that EGF induces EGFR-expressing cancer cells to undergo a transition from the epithelial to the spindle-like mesenchymal morphology. EGF reduced E-cadherin expression and increased that of mesenchymal proteins. In search of a downstream mediator that may account for EGF-induced EMT, we focused on transcription repressors of E-cadherin, TWIST, SLUG, and Snail and found that cancer cells express high levels of TWIST and that EGF enhances its expression. EGF significantly increases TWIST transcripts and protein in EGFR-expressing lines. Forced expression of EGFR reactivates TWIST expression in EGFR-null cells. TWIST expression is suppressed by EGFR and Janus-activated kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) inhibitors, but not significantly by those targeting phosphoinositide-3 kinase and MEK/ERK. Furthermore, constitutively active STAT3 significantly activates the TWIST promoter, whereas the JAK/STAT3 inhibitor and dominant-negative STAT3 suppressed TWIST promoter. Deletion/mutation studies further show that a 26-bp promoter region contains putative STAT3 elements required for the EGF-responsiveness of the TWIST promoter. Chromatin immunoprecipitation assays further show that EGF induces binding of nuclear STAT3 to the TWIST promoter. Immunohistochemical analysis of 130 primary breast carcinomas indicates positive correlations between non-nuclear EGFR and TWIST and between phosphorylated STAT3 and TWIST. Together, we report here that EGF/EGFR signaling pathways induce cancer cell EMT via STAT3-mediated TWIST gene expression. [Cancer Res 2007;67(19):9066–76]
Peroxiredoxin 1 Interacts with Androgen Receptor and Enhances Its Transactivation
Authors: Park Soo-Yeon , Yu Xiaofei , Ip Clement , Mohler James L. , Bogner Paul N. , Park Young-Mee 
Published: October 2007

Abstract
Although hypoxia is accepted as an important microenvironmental factor influencing tumor progression and treatment response, it is usually regarded as a static global phenomenon. Consequently, less attention is given to the impact of dynamic changes in tumor oxygenation in regulating the behavior of cancer cells. Androgen receptor (AR) signaling plays a critical role in prostate cancer. We previously reported that hypoxia/reoxygenation, an in vitro condition used to mimic an unstable oxygenation climate in a tumor, stimulates AR activation. In the present study, we showed that peroxiredoxin 1 (Prx1), a member of the peroxiredoxin protein family, acts as a key mediator in this process. We found that the aggressive LN3, C4-2, and C4-2B prostate cancer cell lines derived from LNCaP possess constitutively elevated Prx1 compared with parental cells, and display greater AR activation in response to hypoxia/reoxygenation. Although the cell survival–enhancing property of Prx1 has traditionally been attributed to its antioxidant activity, the reactive oxygen species–scavenging activity of Prx1 was not essential for AR stimulation because Prx1 itself was oxidized and inactivated by hypoxia/reoxygenation. Increased AR transactivation was observed when wild-type Prx1 or mutant Prx1 (C52S) lacking antioxidant activity was introduced into LNCaP cells. Reciprocal immunoprecipitation, chromatin immunoprecipitation, and in vitro pull-down assays corroborated that Prx1 interacts with AR and enhances its transactivation. We also show that Prx1 is capable of sensitizing a ligand-stimulated AR. Based on the above information, we suggest that disrupting the interaction between Prx1 and AR may serve as a fruitful new target in the management of prostate cancer. [Cancer Res 2007;67(19):9294–303]
Do MDM2 SNP309 and TP53 R72P Interact in Breast Cancer Susceptibility? A Large Pooled Series from the Breast Cancer Association Consortium
Authors: Schmidt Marjanka K. , Reincke Scarlett , Broeks Annegien , Braaf Linde M. , Hogervorst Frans B.L. , Tollenaar Rob A.E.M. , Johnson Nichola , Fletcher Olivia , Peto Julian , Tommiska Johanna , Blomqvist Carl , Nevanlinna Heli A. , Healey Catherine S. , Dunning Alison M. , Pharoah Paul D.P. , Easton Douglas F. , Dörk Thilo , Van't Veer Laura J. ,   on behalf of the Breast Cancer Association Consortium
Published: October 2007

Abstract
Association studies in large series of breast cancer patients can be used to identify single-nucleotide polymorphisms (SNP) contributing to breast cancer susceptibility. Previous studies have suggested associations between variants in TP53 (R72P) and MDM2 (SNP309) and cancer risk. Data from molecular studies suggest a functional interaction between these genes. We therefore investigated the effect of TP53 R72P and MDM2 SNP309 on breast cancer risk and age at onset of breast cancer in a pooled series of 5,191 cases and 3,834 controls from the Breast Cancer Association Consortium (BCAC). Breast cancer risk was not found to be associated with the combined variant alleles [odds ratio (OR), 1.00; 95% confidence interval (95% CI), 0.81–1.23]. Estimated ORs were 1.01 (95% CI, 0.93–1.09) per MDM2 SNP309 allele and 0.98 (95% CI, 0.91–1.04) for TP53 R72P. Although we did find evidence for a 4-year earlier age at onset for carriers of both variant alleles in one of the breast cancer patient series of the BCAC (the German series), we were not able to confirm this effect in the pooled analysis. Even so, carriers of both variant alleles did not have different risk estimates for bilateral or estrogen receptor–positive breast cancer. In conclusion, in this large collaborative study, we did not find an association of MDM2 SNP309 and TP53 R72P, separately or in interaction, with breast cancer. This suggests that any effect of these two variants would be very small and possibly confined to subgroups that were not assessed in our present study. [Cancer Res 2007;67(19):9584–90]