bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diet, nutrition and the prevention of dental diseases
Authors: Moynihan Paula , Petersen Poul Erik 
Published: February 2004

AbstractOral health is related to diet in many ways, for example, nutritional influences on craniofacial development, oral cancer and oral infectious diseases. Dental diseases impact considerably on self-esteem and quality of life and are expensive to treat. The objective of this paper is to review the evidence for an association between nutrition, diet and dental diseases and to present dietary recommendations for their prevention. Nutrition affects the teeth during development and malnutrition may exacerbate periodontal and oral infectious diseases. However, the most significant effect of nutrition on teeth is the local action of diet in the mouth on the development of dental caries and enamel erosion. Dental erosion is increasing and is associated with dietary acids, a major source of which is soft drinks.Despite improved trends in levels of dental caries in developed countries, dental caries remains prevalent and is increasing in some developing countries undergoing nutrition transition. There is convincing evidence, collectively from human intervention studies, epidemiological studies, animal studies and experimental studies, for an association between the amount and frequency of free sugars intake and dental caries. Although other fermentable carbohydrates may not be totally blameless, epidemiological studies show that consumption of starchy staple foods and fresh fruit are associated with low levels of dental caries. Fluoride reduces caries risk but has not eliminated dental caries and many countries do not have adequate exposure to fluoride.It is important that countries with a low intake of free sugars do not increase intake, as the available evidence shows that when free sugars consumption is <15–20kg/yr (~6–10% energy intake), dental caries is low. For countries with high consumption levels it is recommended that national health authorities and decision-makers formulate country-specific and community-specific goals for reducing the amount of free sugars aiming towards the recommended maximum of no more than 10% of energy intake. In addition, the frequency of consumption of foods containing free sugars should be limited to a maximum of 4 times per day. It is the responsibility of national authorities to ensure implementation of feasible fluoride programmes for their country.
Increase in the conformational flexibility of β2‐microglobulin upon copper binding: A possible role for copper in dialysis‐related amyloidosis
Authors: Villanueva James , Hoshino Masaru , Katou Hidenori , Kardos József , Hasegawa Kazuhiro , Naiki Hironobu , Goto Yuji 
Published: February 2004

AbstractA key pathological event in dialysis‐related amyloidosis is the fibril formation of β2‐microglobulin (β2‐m). Because β2‐m does not form fibrils in vitro, except under acidic conditions, predisposing factors that may drive fibril formation at physiological pH have been the focus of much attention. One factor that may be implicated is Cu2+ binding, which destabilizes the native state of β2‐m and thus stabilizes the amyloid precursor. To address the Cu2+‐induced destabilization of β2‐m at the atomic level, we studied changes in the conformational dynamics of β2‐m upon Cu2+ binding. Titration of β2‐m with Cu2+ monitored by heteronuclear NMR showed that three out of four histidines (His13, His31, and His51) are involved in the binding at pH 7.0. 1H‐15N heteronuclear NOE suggested increased backbone dynamics for the residues Val49 to Ser55, implying that the Cu2+ binding at His51 increased the local dynamics of β‐strand D. Hydrogen/deuterium exchange of amide protons showed increased flexibility of the core residues upon Cu2+ binding. Taken together, it is likely that Cu2+ binding increases the pico‐ to nanosecond fluctuation of the β‐strand D on which His51 exists, which is propagated to the core of the molecule, thus promoting the global and slow fluctuations. This may contribute to the overall destabilization of the molecule, increasing the equilibrium population of the amyloidogenic intermediate.
The peculiar nature of unfolding of the human prion protein
Authors: Baskakov Ilia V. , Legname Giuseppe , Gryczynski Zygmunt , Prusiner Stanley B. 
Published: February 2004

AbstractSpontaneous conformational transition of the prion protein from an α‐helical isoform to a β‐sheet‐rich isoform underlies the pathogenesis of sporadic prion diseases. To study the rate‐limiting steps of spontaneous conversion, the formation of amyloid fibrils by the recombinant human PrP C‐terminal fragment spanning residues 90–231 (recPrP) was monitored in the presence of urea. The kinetics of spontaneous fibril formation displayed sigmoidal behavior involving a lag phase. The shortest lag phase was observed at partially denaturing conditions, close to the concentration of urea corresponding to the middle point of unfolding. This result indicates that unfolding intermediates may be important for the conversion. To test whether unfolding intermediates are formed, we employed size‐exclusion chromatography and circular dichroism spectroscopy to monitor urea denaturation of recPrP. Both techniques showed a single sigmoidal transition with very similar thermodynamic parameters of denaturation and that the transition can be described by a simple equilibrium between folded and denatured states. Detailed analyses of data, however, revealed that the dimensions of both the native and denatured species gradually increases with urea. Expansion of the native species is also accompanied by an increase in efficiency of the energy transfer from a single Trp residue to 1‐anilinonaphthalene‐8‐sulfonate dye as measured by fluorescence. These data illustrate that thermodynamic character of the native ensemble changes gradually with environmental conditions. Such behavior is consistent with the thermodynamically variable model, and may be linked to the ability of PrP to adopt distinct abnormal conformations under pathologic conditions.
Crystal structure of the phosphorolytic exoribonuclease RNase PH from Bacillus subtilis and implications for its quaternary structure and tRNA binding
Authors: Harlow Lene S. , Kadziola Anders , Jensen Kaj Frank , Larsen Sine 
Published: February 2004

AbstractRNase PH is a member of the family of phosphorolytic 3′ → 5′ exoribonucleases that also includes polynucleotide phosphorylase (PNPase). RNase PH is involved in the maturation of tRNA precursors and especially important for removal of nucleotide residues near the CCA acceptor end of the mature tRNAs. Wild‐type and triple mutant R68Q‐R73Q‐R76Q RNase PH from Bacillus subtilis have been crystallized and the structures determined by X‐ray diffraction to medium resolution. Wild‐type and triple mutant RNase PH crystallize as a hexamer and dimer, respectively. The structures contain a rare left‐handed βαβ‐motif in the N‐terminal portion of the protein. This motif has also been identified in other enzymes involved in RNA metabolism. The RNase PH structure and active site can, despite low sequence similarity, be overlayed with the N‐terminal core of the structure and active site of Streptomyces antibioticus PNPase. The surface of the RNase PH dimer fit the shape of a tRNA molecule.
Steric restrictions in protein folding: An α‐helix cannot be followed by a contiguous β‐strand
Authors: Fitzkee Nicholas C. , Rose George D. 
Published: February 2004

AbstractUsing only hard‐sphere repulsion, we investigated short polyalanyl chains for the presence of sterically imposed conformational constraints beyond the dipeptide level. We found that a central residue in a helical peptide cannot adopt dihedral angles from strand regions without encountering a steric collision. Consequently, an α‐helical segment followed by a β‐strand segment must be connected by an intervening linker. This restriction was validated both by simulations and by seeking violations within proteins of known structure. In fact, no violations were found within an extensive database of high‐resolution X‐ray structures. Nature's exclusion of α‐β hybrid segments, fashioned from an α‐helix adjoined to a β‐strand, is built into proteins at the covalent level. This straightforward conformational constraint has far‐reaching consequences in organizing unfolded proteins and limiting the number of possible protein domains.
Regulation of the Human Acute Phase Serum Amyloid A Genes by Tumour Necrosis Factor‐α, Interleukin‐6 and Glucocorticoids in Hepatic and Epithelial Cell Lines
Authors: Thorn C. F. , Lu Z.‐Y. , Whitehead A. S. 
Published: February 2004

AbstractThe major acute‐phase protein serum amyloid A, A‐SAA, is upregulated by a variety of inflammatory stimuli, including cytokines and glucocorticoids (GCs). Elevated systemic concentrations of both A‐SAA and tumour necrosis factor (TNF)‐α are a feature of inflammatory diseases, such as rheumatoid arthritis and inflammatory bowel disease.Here, we examine the roles of TNF‐α, interleukin‐6 (IL‐6) and GCs on the transcriptional regulation of the two human A‐SAA genes (SAA1 and SAA2) and show that these stimuli have different effects on the SAA1 and SAA2 promoters in HepG2 hepatoma and KB epithelial cell lines. Both genes are induced modestly by TNF‐α and IL‐6 alone and synergistically by TNF‐α plus IL‐6. The TNF‐driven induction of SAA1, but not that of SAA2, can be enhanced by GCs in both cell lines, whereas GCs alone can upregulate SAA1 only in epithelial cells. The upregulation of both genes by cytokines, and of SAA1 by GCs, is more rapid in epithelial cells than hepatoma cells.We established that the order in which either cell line was treated with TNF‐α and IL‐6 influenced A‐SAA promoter transcriptional activation. Treatment with TNF‐α followed by IL‐6 resulted in a much greater induction of both A‐SAA genes than treatment with IL‐6 followed by TNF‐α.
Decreased CD4+CD25+ T Cells in Peripheral Blood of Patients with Systemic Lupus Erythematosus
Authors: Liu M.‐F. , Wang C.‐R. , Fung L.‐L. , Wu C.‐R. 
Published: February 2004

AbstractRecent animal studies have shown that CD4+CD25+ T cells play a crucial role in the suppression of the immune response and that depletion of this subset of T cells might lead to development of autoimmune diseases. The aim of the present study was to investigate the levels of CD4+CD25+ T cells in the peripheral blood of patients with systemic lupus erythematosus (SLE). Ninety‐four SLE patients, 52 patients with rheumatoid arthritis (RA) and 50 age‐ and gender‐matched healthy individuals were enrolled in the study. A flowcytometric method was applied in the measurement of CD4+CD25+ T cells. The results showed that patients with SLE had statistically lower levels of CD4+CD25+ T cells than did normal controls, when expressed as either percentages of peripheral blood mononuclear cells (PBMCs) (mean ± SD, 8.49 ± 6.36 versus 11.11 ± 4.58%, P < 0.05) or absolute cell numbers (98.77 ± 97.52 versus 213.93 ± 104.52 cells/mm3, P < 0.05). In terms of CD25brightCD4+ T cells, defined as having a fluorescence intensity of CD25 expression exceeding 100, SLE patients still had significantly lower levels than did normal controls expressed as percentages of PBMCs (1.76 ± 1.32 versus 3.73 ± 1.30%, P < 0.05). No significant differences could be found between RA patients and normal controls. The overwhelming majority of CD4+CD25+ T cells belonged to CD45RO+ cells and most did not express the CD69 molecule. Although decreased CD4+CD25+ T cells were found in SLE patients, we failed to find a significant correlation between the levels of CD4+CD25+ T cells and disease activities of SLE. To the best of our knowledge, this is the first study to demonstrate that patients with SLE had decreased CD4+CD25+ T cells. However, the exact role of the decreased CD4+CD25+ T cells in the pathogenesis of SLE remains to be elucidated.
Methylated CpG‐Containing Plasmid Activates the Immune System
Authors: Cornélie S. , Poulain‐Godefroy O. , Lund C. , Vendeville C. , Ban E. , Capron M. , Riveau G. 
Published: February 2004

AbstractBacterial DNA differs from mammalian DNA by the presence of unmethylated cytosine–phosphate–guanosine (CpG) motifs. The immunostimulatory properties of a DNA vaccine have been suspected to be associated with these motifs. The aim of this study was to assess the inactivation of the immunostimulatory potential of a plasmid after methylation of its CpG motifs. We constructed two identical non‐coding plasmids, and one of these was de novo methylated on its CG sequences. A single administration of recombinant antigen with methylated or unmethylated CpG‐containing plasmid was performed in mice. As expected, only unmethylated CpG‐containing plasmid enhanced the specific immune response. However, a study of in vivo activation of Langerhans' cells and analysis of mRNA synthesis indicated that both the plasmids promoted cell emigration and cytokine induction. These data highlight that a methylated CpG‐containing plasmid is not inert and carries immunomodulatory properties. The results further emphasize the necessity to definitively identify the mode of action of plasmids used for DNA vaccination.
Simple Electrostatic Interaction Mechanisms in the Service of HIV‐1 Pathogenesis
Authors: Krambovitis E. , Zafiropoulos A. , Baritaki S. , Spandidos D. A. 
Published: February 2004

AbstractThe main cell population affected by the human immunodeficiency virus‐1 (HIV‐1) infection belongs to the CD4+ T‐lymphocyte family. Recent convincing evidence indicates that the majority of the cells that die due to HIV‐1 are not actually infected by the virus. Instead, these cells are being led to programmed cell death after the activation of apoptotic mechanisms by the virus or its components. We propose here from accumulated evidence that the virus appears to deregulate the physiological function of these cells during the process of antigen presentation. Ionic interactions between the variable V3 domain of the HIV‐1 coat glycoprotein gp120 and the amino terminal of the chemokine receptor CCR5 play a prominent role in this process, and we speculate that nature has evolved simple electrostatic interaction mechanisms which, coupled to specific recognition systems on the cell surface, can initiate and modulate certain cellular events without the need for specific molecular structures. HIV‐1 utilizes such a mechanism to ensure activation of the target host cell.
Debridement and local application of tetracycline‐loaded fibres in the management of persistent periodontitis: results after 12 months
Authors: Aimetti M. , Romano F. , Torta I. , Cirillo D. , Caposio P. , Romagnoli R. 
Published: February 2004

AbstractBackgrounds, aims: The aim of our study was to evaluate the clinical, radiological and microbiological response to the local delivery of tetracycline (TE) of sites with persistent periodontal lesions.Material and Methods: The study was conducted in a split‐mouth design. Nineteen patients with at least four bilateral pockets 4–5 mm and bleeding on probing (BOP) were treated with scaling and root planing (SRP) plus TE fibres (test sites) or with SRP alone (control sites). Clinical and radiological measurements were taken at baseline, 6 months and 12 months post‐operatively. Subgingival plaque samples were collected at baseline, at fibres removal, 6 and 12 months following treatment and analysed by polymerase chain reaction.Results: Both treatments yielded a statistically significant (p<0.05) reduction of probing depth (2.05 and 1.21 mm), gain of clinical attachment level (1.71 and 0.53 mm) and reduction of BOP scores (23.68% and 57.89%) for TE and SRP groups, respectively, when comparing 12‐month data with baseline. The differences between two groups were significant. The prevalence of Treponema denticola and Bacteroides forsythus decreased after therapy in both groups but only in the test sites Actinobacillus actinomycetemcomitans and Prevotella intermedia were not yield detected. The pathogens could be eliminated from five periodontal pockets by SRP alone, while 21 TE sites were not recolonized at 12 months.Conclusions: SRP plus TE fibres gave the greatest advantage in the treatment of periodontal persistent lesions at least 12 months following treatment.
Quadrant root planing versus same‐day full‐mouth root planing
Authors: Apatzidou D. A. , Kinane D. F. 
Published: February 2004

AbstractObjectives: The aim of this study was to determine whether same‐day full‐mouth scaling and root planing (FM‐SRP) and quadrant scaling and root planing (Q‐SRP) resulted in variations in the systemic humoral immune response dynamics (antibody titres and avidity) during active treatment and 3 and 6 months post‐therapy.Material and Methods: Forty patients with chronic periodontitis were recruited into this study. Subjects were randomised into two groups and received either scaling and root planing quadrant by quadrant at 2‐weekly intervals (Q‐SRP group) or same‐day full‐mouth scaling and root planing (FM‐SRP group). Clinical measurements and serum samples were obtained at baseline and approximately 6 weeks after the last clinical intervention (R1) and 6 months after the initiation of therapy (R2). Furthermore, serum samples were obtained from each patient undergoing therapy (Q‐SRP and FM‐SRP) at 3 bi‐weekly instances so as to determine the short‐term effects of each session of scaling and root planing on the dynamics of the humoral immune response. Serum antibody titre was assayed by enzyme‐linked immunosorbent assay (ELISA) and antibody avidity was measured by thiocyanate dissociation against five putative periodontal pathogens: Porphyromonas gingivalis; Actinobacillus actinomycetemcomitans; Prevotella intermedia; Treponema denticola and Bacteroides forsythus.Results: Both therapies resulted in similar antibody titre reductions against the majority of the organisms tested and although there was a distinct trend for antibody avidity to increase following therapy, this was not found to be statistically significant, reflecting marked inter‐individual variation. In addition, no evidence emerged from this study to support increased antibody titres following the active phases of both treatment approaches due to an inoculation effect. Nevertheless, significant short‐term increases in antibody avidity to most test bacteria were noted for both treatment strategies.Conclusion: Both therapies were associated with a reduction in antibody titres and an increase in the binding ability or avidity of antibodies, but there was a marked inter‐subject variability and statistical significance was reached for only some of the test bacteria. No significant differences in the humoral antibody dynamics were found between the two treatment approaches.
Accuracy of probing attachment levels using a CEJ Probe versus traditional probes
Authors: Karpinia K. , Magnusson I. , Gibbs C. , Yang M. C. K. 
Published: February 2004

AbstractBackground: Current interest in the assessment of probing attachment level measurements has been stimulated by recent introduction of novel periodontal probes as well as by the reclassification of periodontal diseases. Clinical attachment level (CAL) is currently the “gold standard” for diagnosing and monitoring periodontal diseases.Aim: To evaluate the performance of the newly introduced cementoenamel junction (CEJ) Probe in detecting CAL using the CEJ as a fixed reference point, and to compare the CEJ Probe with the Florida Disk Probe and a standard Manual Probe (North Carolina Probe).Material and Methods: Three examiners probed 12 periodontal patients to determine intra‐ and inter‐consistency of both the probes and the examiners, over a 4‐week time interval. Subjects ranged in age from 22 to 74 years. The experimental design was structured to balance the intra‐ and inter‐examiner consistency at the same site during the two visits.Results: Using the PROC MIXED of SAS, a strong interaction (p<0.001) between the examiner and probes was found. The consistency of probing (repeatability of measurements) depended upon the type of periodontal probe used as well as the skill (experience) of the examiner. Overall, the CEJ Probe displayed a more consistent performance. The CEJ Probe demonstrated greater intra‐examiner consistency than the Disk Probe for two examiners (p<0.01). The CEJ Probe also showed increased inter‐examiner consistency (p<0.01).Conclusions: The CEJ Probe has the potential to offer the dental team an efficient, accurate mechanism to chart and monitor attachment level measurements over time. Additional studies, using large numbers of examiners, are needed to assess more clearly the performance of each individual probe.
Effect of a combination of amine/stannous fluoride dentifrice and mouthrinse in periodontal maintenance patients
Authors: Paraskevas S. , Danser M. M. , Timmerman M. F. , Van der Velden U. , Van der Weijden G. A. 
Published: February 2004

AbstractAim:The purpose of the present study was to evaluate the beneficial effect of using a dentifrice and mouthrinse containing amine fluoride (AmF) and stannous fluoride (SnF2) in a group of periodontal maintenance patients. Efficacy parameters were plaque, gingival inflammation, pocket depth and attachment loss. An additional parameter was development of stain.Material and Methods:In total, 80 patients who had been treated for moderate‐to‐severe periodontitis agreed to participate in this study. Subjects received supportive periodontal therapy at regular intervals of 3–4 months for at least a period of 1 year. The patients were randomly divided into two groups: (1) the test group used an AmF/SnF2dentifrice and mouthrinse and (2) the control group used a sodium fluoride (NaF)‐containing dentifrice and mouthrinse. Clinical assessments were performed at baseline, 3, 6, 12, 18 and 24 months.Results:The mean plaque index score after 3 months in the test group (0.24) was significantly lower than that in control group (0.34) (p0.05), a difference that was maintained throughout the remainder of the study. In terms of bleeding on probing, at no point in time were significant differences between test and control group found. No significant differences were noted between the two groups, nor were there any significant changes in comparison with baseline values with respect to pocket depth and attachment level. At baseline, the mean percentage of sites with no staining was 98% for both the test and control groups. At all further assessments, the staining in both groups was elevated as compared with baseline. Smoking did not affect the outcome of the study.Conclusion:The combined use of an AmF/SnF2dentifrice and mouthrinse did not affect the parameters of inflammation (bleeding upon marginal probing and probing pocket depth), but it has shown to be more effective in terms of plaque reduction when compared with the use of an NaF dentifrice and mouthrinse in a group of periodontal patients placed under regular maintenance care.