bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of carbon isotopes in the glacial ocean: A model study
Authors: Crucifix Michel
Published: December 2005

A series of simulations are conducted with a global climate model of intermediate complexity (MoBidiC). This model includes ocean circulation dynamics, including the carbon cycle, coupled to a zonally averaged atmosphere. Oceanic distributions of nutrients, apparent oxygen utilization, radiocarbon, and carbon 13 are discussed for the preindustrial era (validation) as well as three states of the glacial ocean, termed interstadial (very active formation of deep water in the North Atlantic Ocean), stadial (moderate convection and important flow of Antarctic Deep Water in the Atlantic), and Heinrich (no formation of North Atlantic Deep Water). The stadial and interstadial states are stable. The Heinrich state is forced by a continuous freshwater discharge into the North Atlantic. The model exhibits significant changes in the isotopic composition of the ocean between the three modeled glacial states. Results for δ13C tend to be in qualitative agreement with paleoceanographic data, except that the model fails at representing the strong depletion in δ13C in the Southern Ocean. The Heinrich Atlantic Ocean is older than the stadial ocean at all depths (up to 1500 years). The “interstadial” ocean has younger deep water and older intermediate water than the “stadial.” It is recognized that the simulated changes in intermediate water age are less reliable because of the structure of the model. Color tracers are used to show that changes in the isotopic composition of Atlantic bottom water are mainly related to a redistribution of water masses. A simple method is tested, by which it is possible to reconstruct the North Atlantic water flow from the zonal profiles of salinity and Δ14C. Finally, dividing artificially the gas exchange rate in the Southern Ocean by four results in a 0.4‰ decrease in the δ13C of Antarctic Bottom Water. Changes in new production are, comparatively, less effective at altering the δ13C ratio.
Slow dynamics of the Northern Hemisphere glaciation
Authors: Mudelsee Manfred , Raymo Maureen E.
Published: December 2005

Unraveling the dynamics of the Northern Hemisphere glaciation (NHG) in the Pliocene is a key step toward a quantitative theory of the climate transition from a greenhouse to an icehouse world. Extracting the ice volume signal from marine oxygen isotope (δ18O) records corrupted with “temperature noise” can be accomplished using statistical time series analysis. We use 45 δ18O records from benthic and planktonic foraminifera and globally distributed sites to reconstruct the dynamics of NHG initiation. We compare δ18O amplitudes with those of temperature proxy records and estimate a global ice volume–related increase of 0.4‰, equivalent to an overall sea level lowering of 43 m. We find the NHG started significantly earlier than previously assumed, as early as 3.6 Ma, and ended at 2.4 Ma. This long‐term increase points to slow, tectonic forcing such as closing of ocean gateways or mountain building as the root cause of the NHG.
DNA methylation patterns in in vitro-fertilised goat zygotes
Authors: Hou J. , Lei T. H. , Liu L. , Cui X. H. , An X. R. , Chen Y. F.
Published: December 2005

Recent studies have shown that zygote demethylation patterns in mammals are variable among species. However, the methylation patterns of goat zygotes have not yet been reported on. In the present study, using immunofluorescence staining with an antibody against 5-methylcytosine, the methylation patterns of in vitro-derived goat zygotes were studied. The results indicate that goat zygotes do not undergo active global demethylation during pronuclei development, which is similar to the situation in ovine, but not in murine or bovine zygotes. This is believed to be the first report regarding methylation in goat zygotes.
Discovery of an ornithurine bird and its implication for Early Cretaceous avian radiation
Authors: Zhou Zhonghe , Zhang Fucheng
Published: December 2005

An ornithurine bird,Hongshanornis longicrestagen. et sp. nov., represented by a nearly complete and articulated skeleton in full plumage, has been recovered from the lacustrine deposits of the Lower Cretaceous Jehol Group in Inner Mongolia, northeast China. The bird had completely reduced teeth and possessed a beak in both the upper and lower jaws, representing the earliest known beaked ornithurine. The preservation of a predentary bone confirms that this structure is not unique to ornithischian dinosaurs but was common in early ornithurine birds. This small bird had a strong flying capability with a low aspect ratio wing. It was probably a wader, feeding in shallow water or marshes. This find confirms that the aquatic environment had played a key role in the origin and early radiation of ornithurines, one branch of which eventually gave rise to extant birds near the Cretaceous/Tertiary boundary. This discovery provides important information not only for studying the origin and early evolution of ornithurines but also for understanding the differentiation in morphology, body size, and diet of the Early Cretaceous birds.
Lipid- and receptor-binding regions of apolipoprotein E4 fragments act in concert to cause mitochondrial dysfunction and neurotoxicity
Authors: Chang Shengjun , Ma Tian ran , Miranda R. Dennis , Balestra Maureen E. , Mahley Robert W. , Huang Yadong
Published: December 2005

Apolipoprotein (apo) E4, a 299-aa protein and a major risk factor for Alzheimer's disease, can be cleaved to generate C-terminal-truncated fragments that cause neurotoxicity
in vitro
and neurodegeneration and behavioral deficits in transgenic mice. To investigate this neurotoxicity, we expressed apoE4 with C- or N-terminal truncations or mutations in transfected Neuro-2a cells. ApoE4 (1-272) was neurotoxic, but full-length apoE4(1-299) and apoE4(1-240) were not, suggesting that the lipid-binding region (amino acids 241-272) mediates the neurotoxicity and that amino acids 273-299 are protective. A quadruple mutation in the lipid-binding region (I250A, F257A, W264R, and V269A) abolished the neurotoxicity of apoE4(1-272), and single mutations in the region of amino acids 273-299 (L279Q, K282A, or Q284A) made full-length apoE4 neurotoxic. Immunofluorescence staining showed that apoE4(1-272) formed filamentous inclusions containing phosphorylated tau in some cells and interacted with mitochondria in others, leading to mitochondrial dysfunction as determined by MitoTracker staining and flow cytometry. ApoE4(241-272) did not cause mitochondrial dysfunction or neurotoxicity, suggesting that the lipid-binding region alone is insufficient for neurotoxicity. Truncation of N-terminal sequences (amino acids 1-170) containing the receptor-binding region (amino acids 135-150) and triple mutations within that region (R142A, K146A, and R147A) abolished the mitochondrial interaction and neurotoxicity of apoE4(1-272). Further analysis showed that the receptor-binding region is required for escape from the secretory pathway and that the lipid-binding region mediates mitochondrial interaction. Thus, the lipid- and receptor-binding regions in apoE4 fragments act together to cause mitochondrial dysfunction and neurotoxicity, which may be important in Alzheimer's disease pathogenesis.
Cumulation from Proper Specification: Theory, Logic, Research Design, and “Nice” Laws
Authors: Starr Harvey
Published: December 2005

Jim Ray has set out a challenge to students of international conflict: how can we improve our research to do better in the cumulation of knowledge and understanding of international phenomena? While most of the commentary in this special issue revolves about more technical statistical issues, the questions that Ray raises must also be addressed not just on statistical/methods grounds, but within the context of broader theoretical concerns and theoretical specification. That is the aim of this article. Drawing on the concept of the “research triad” of logic, theory, and methodology presented by Most & Starr (1989), this article will stress the relationship of theory to the development of research designs that will permit both the additive and integrative cumulation of knowledge. This article will discuss how statistical model specification can be informed by broader principles of research design, demonstrating how Ray's basic points are supported by earlier, complementary, and converging lines of argument.
Short article: Conformity to the power PC theory of causal induction depends on the type of probe question
Authors: Collins Darrell J. , Shanks David R.
Published: December 2005

P. W. Cheng's (1997) power PC theory of causal induction proposes that causal estimates are based on the power ( P) of a potential cause, where P is the contingency between the cause and effect normalized by the base rate of the effect. Most previous research using a standard causal probe question has failed to support the predictions of the power PC model but recently Buehner, Cheng, and Clifford (2003) found that participants responded in terms of causal power when probed with a counterfactual test question, which they argued prompted participants to consider the base rate of the effect. However, Buehner et al. framed their counterfactual question in terms of frequency, a factor that has been demonstrated to decrease base rate neglect in judgements under uncertainty. In the experiment reported here, we sought to disentangle the influence of counterfactual and frequency framing of the probe question to determine which factor is responsible for encouraging responses in terms of causal power.
The mammalian Scribble polarity protein regulates epithelial cell adhesion and migration through E-cadherin
Authors: Qin Yi , Capaldo Christopher , Gumbiner Barry M. , Macara Ian G.
Published: December 2005

Scribble (Scrib) is a conserved polarity protein required in Drosophila melanogaster for synaptic function, neuroblast differentiation, and epithelial polarization. It is also a tumor suppressor. In rodents, Scrib has been implicated in receptor recycling and planar polarity but not in apical/basal polarity. We now show that knockdown of Scrib disrupts adhesion between Madin–Darby canine kidney epithelial cells. As a consequence, the cells acquire a mesenchymal appearance, migrate more rapidly, and lose directionality. Although tight junction assembly is delayed, confluent monolayers remain polarized. These effects are independent of Rac activation or Scrib binding to βPIX. Rather, Scrib depletion disrupts E-cadherin–mediated cell–cell adhesion. The changes in morphology and migration are phenocopied by E-cadherin knockdown. Adhesion is partially rescued by expression of an E-cadherin–α-catenin fusion protein but not by E-cadherin–green fluorescent protein. These results suggest that Scrib stabilizes the coupling between E-cadherin and the catenins and are consistent with the idea that mammalian Scrib could behave as a tumor suppressor by regulating epithelial cell adhesion and migration.
Robert Hooke's conical pendulum from the modern viewpoint of amplitude equations and its optical analogues
Authors: Rousseaux Germain , Coullet Pierre , Gilli Jean-Marc
Published: December 2005

As stated by Lord Kelvin a long time ago, ‘It seems to me that the test of “Do we or do we not understand a particular point in physics?” is, “Can we make a mechanical model of it?”’

What is the relationship between the propagation of a light wave in a Kerr medium in the presence of a magnetic field and the oscillation of a spherical pendulum on a rotating platform?

A Kerr medium is one that when submitted to an electric field its refraction index becomes a non-linear function of the latter.

It is Robert Hooke who first studied the motion of a spherical pendulum in order to approach the notion of central force. Indeed, he was willing to explore the motion of the planets with this analogous device. As a matter of fact, when a pendulum made up of a heavy mass, representing the Earth, and hanging on a wire is moved away from its equilibrium position vertically from the point of suspension, it undergoes a restoring force which tends to bring it back to the center, similar to the gravitational force exerted by the Sun on the Earth. For small amplitudes the trajectories are ellipses which precess. The ellipses are centered on the axis, in contrast to the case of planets, where the attractive center corresponds to one of the focii of the elliptical path.

Thanks to the modern formalism of nonlinear dynamics, we were able to show the close relationships between the equations which describe the motion of the pendulum and the propagation of the light wave in a Kerr medium. In both cases, an elliptical motion is induced.

It is interesting to note that the application of a magnetic field to a Kerr medium translates into an angular rotation which induces an additional precession of the pendulum—well known as the Foucault effect.
A missense mutation in the bovine SLC35A3 gene, encoding a UDP-N-acetylglucosamine transporter, causes complex vertebral malformation
Authors: Thomsen Bo , Horn Per , Panitz Frank , Bendixen Emøke , Petersen Anette H. , Holm Lars-Erik , Nielsen Vivi H. , Agerholm Jørgen S. , Arnbjerg Jens , Bendixen Christian
Published: December 2005

The extensive use of a limited number of elite bulls in cattle breeding can lead to rapid spread of recessively inherited disorders. A recent example is the globally distributed syndrome Complex Vertebral Malformation (CVM), which is characterized by misshapen and fused vertebrae around the cervico-thoracic junction. Here, we show that CVM is caused by a mutation in the Golgi-resident nucleotide-sugar transporter encoded by SLC35A3. Thus, the disease showed complete cosegregation with the mutation in a homozygous state, and proteome patterns indicated abnormal protein glycosylation in tissues of affected animals. In addition, a yeast mutant that is deficient in the transport of UDP-N-acetylglucosamine into its Golgi lumen can be rescued by the wild-type SLC35A3 gene, but not by the mutated gene. These results provide the first demonstration of a genetic disorder associated with a defective SLC35A3 gene, and reveal a new mechanism for malformation of the vertebral column caused by abnormal nucleotide-sugar transport into the Golgi apparatus.
Abundant novel transcriptional units and unconventional gene pairs on human chromosome 22
Authors: Lipovich Leonard , King Mary-Claire
Published: December 2005

Novel transcriptional units (TUs) are EST-supported transcribed features not corresponding to known genes. Unconventional gene pairs (UGPs) are pairs of genes and/or TUs sharing exon-to-exon cis-antisense overlaps or putative bidirectional promoters. Computational TU and UGP discovery followed by manual curation was performed in the entire published 34.9-Mb human chromosome 22 euchromatic sequence. Novel TUs (n = 517) were as abundant as known genes (n = 492) and typically did not have nonprimate DNA and protein homologies. One hundred seventy-one (33%) of TUs, but only 13 (3%) of genes, both lacked nonprimate conservation and localized to gaps in the human–mouse BLASTZ alignment. Novel TUs were richer in exonic primate-specific interspersed repetitive elements (P = 0.001) and were more likely to rely on splice junctions provided by them, than were known genes: 19% of spliced TUs, versus 5% of spliced genes, had a splice site within a primate-specific repeat. Hence, novel TUs and known genes may represent different portions of the transcriptome. Two hundred nine (21%) of chromosome 22 transcripts participated in 77 cis-antisense and 42 promoter-sharing UGPs. Transcripts involved simultaneously in both UGP types were more common than was expected (P = 0.01). UGPs were nonrandomly distributed along the sequence: 89 (75%) clustered in distinct regions, the sum of which equaled 4.4 Mb (<13% of the chromosome). Eighty (67%) of the UGPs possessed significant locus structure differences between primates and rodents. Since some TUs may be functional noncoding transcripts and since the cis-regulatory potential of UGPs is well recognized, TUs and UGPs specific to the primate lineage may contribute to the genomic basis for primate-specific phenotypes.
Comparative evaluation of a new bedside faecal occult blood test in a prospective multicentre study
Authors: HOEPFFNER N. , SHASTRI Y. M. , HANISCH E. , RÖSCH W. , MÖSSNER J. , CASPARY W. F. , STEIN J.
Published: December 2005

Background

Faecal occult blood testing is an established method of colorectal neoplasia screening. Guaiac‐based tests are limited by poor patient compliance, low sensitivity, specificity and positive predictive value. Newer immunochemical‐based tests, accurate but tedious, require a well‐established laboratory set up. There is need for simpler immunochemical tests that can be performed at the out‐patient clinic.

Aim

To compare the performance characteristics of a new bedside immunological test strip device with a sensitive Guaiac‐based and established immunochemical test for detection of faecal occult blood in patients undergoing colonoscopy.

Methods

A total of 389 consecutive patients from four centres who were referred for colonoscopy also provided the stool samples for detection of occult blood without dietary restrictions. Stool tests performed were (i) Guaiac‐based, (ii) immunochemical enzyme‐linked immunosorbent assay and (iii) bedside immunochemical strip test.

Results

At the optimal threshold level, the sensitivity and specificity of the beside immunochemical strip test for detection of significant colorectal neoplasia (adenomas >1.0 cm and carcinomas) were 60% and 95%, respectively.

Conclusions

This bedside immunochemical strip test proved to be a simple, convenient, non‐cumbersome and accurate tool with similar performance characteristics for detection of any bleeding lesion including colorectal neoplasia when compared with an established immunochemical faecal occult blood test.
Peroxisome proliferator‐activated receptor‐α and ‐γ mRNA levels are reduced in chronic hepatitis C with steatosis and genotype 3 infection
Authors: DE GOTTARDI A. , PAZIENZA V. , PUGNALE P. , BRUTTIN F. , RUBBIA‐BRANDT L. , JUGE‐AUBRY C. E. , MEIER C. A. , HADENGUE A. , NEGRO F.
Published: December 2005

Background

Steatosis in chronic hepatitis C is associated with inflammation and accelerated fibrogenesis.

Aim

To assess the contribution of peroxisome proliferator‐activated receptor‐α and ‐γ to the pathogenesis of hepatitis C virus associated steatosis is unknown.

Methods

We measured peroxisome proliferator‐activated receptor (PPAR)‐α and ‐γ mRNA by quantitative polymerase chain reaction in liver biopsies of 35 genotype 1 and 22 genotype 3 infected patients and in Huh7 cells expressing hepatitis C virus 1b or 3a core protein.

Results

PPAR‐α mRNA was significantly reduced in livers of patients with genotype 3 compared with genotype 1. Steatosis was associated to a decreased expression of PPAR‐α in genotype 1, but not in genotype 3. PPAR‐γ expression was significantly lower in genotype 3 compared with genotype 1 and steatosis was associated to decreased levels of PPAR‐γ, but only in genotype 1. There was no significant relationship between PPARs mRNA levels and liver activity or fibrosis. Expression of the hepatitis C virus 3a core protein was associated with an increase in triglyceride accumulation and with a significant reduction of PPAR‐γ mRNA compared with hepatitis C virus 1b.

Conclusions

The presence of steatosis and hepatitis C virus genotype 3 are both associated with a significant down‐regulation of PPARs. These receptors, and also additional factors, seem to play a role in the pathogenesis of hepatitis C virus‐associated steatosis.
Effect of vardenafil, an inhibitor of phosphodiesterase‐5, on portal haemodynamics in normal and cirrhotic liver – results of a pilot study
Authors: DEIBERT P. , SCHUMACHER Y.‐O. , RUECKER G. , OPITZ O. G. , BLUM H. E. , RÖSSLE M. , KREISEL W.
Published: December 2005

Background  Dysregulation of the cyclic guanosine 3′,5′ monophosphate–nitric oxide system is in part responsible for portal hypertension in cirrhosis.

Aim  To test the effects of inhibitors of phosphodiesterase‐5 on portal haemodynamics.

Methods  To 18 healthy subjects and 18 patients with Child A liver cirrhosis, 10 mg of vardenafil, an inhibitor of phosphodiesterase‐5, were administered orally. Doppler sonographic measurements of hepatic and splanchnic blood flow, systemic blood pressure and heart rate were recorded before, 1 h after, and 48 h after the application. Vardenafil plasma levels were determined after 1 h. In five patients, invasive registration of free and wedged hepatic vein pressure was performed.

Results  Portal venous flow increased in patients from 0.82 ± 0.30 L/min (mean ± s.d.) by 26% (CI: 16–37%, P = 0.0004) and in healthy subjects from 0.75 ± 0.20 L/min (mean ± s.d.) by 19% (CI: 9–28%; P = 0.0010). Celiac and hepatic artery resistivity indices rose significantly. Systemic blood pressure decreased slightly in patients. The wedged hepatic venous pressure gradient decreased in four of five patients with liver cirrhosis. Vardenafil plasma levels were higher in patients (14 ± 10 μg/L) than in healthy subjects (9 ± 6 μg/L; n.s.).

Conclusions  Inhibition of phosphodiesterase‐5 increases portal flow and lowers portal pressure by a decrease in sinusoidal resistance and may be a novel therapeutic strategy for portal hypertension.
Levofloxacin does not decrease mortality in Staphylococcus aureus bacteraemia when added to the standard treatment: a prospective and randomized clinical trial of 381 patients
Authors: RUOTSALAINEN E. , JÄRVINEN A. , KOIVULA I. , KAUMA H. , RINTALA E. , LUMIO J. , KOTILAINEN P. , VAARA M. , NIKOSKELAINEN J. , VALTONEN V. ,   THE FINLEVO STUDY GROUP
Published: December 2005

Objectives.  To study whether levofloxacin, added to standard treatment, could reduce the high mortality and complication rates in Staphylococcus aureus bacteraemia.

Design.  A prospective randomized multicentre trial from January 2000 to August 2002.

Setting.  Thirteen tertiary care or university hospitals in Finland.

Subjects.  Three hundred and eighty‐one adult patients with S. aureus bacteraemia. Patients with meningitis, and those with fluoroquinolone‐ or methicillin‐resistant S. aureus were excluded.

Interventions.  Standard treatment (mostly semisynthetic penicillin) (n = 190) or that combined with levofloxacin (n = 191). Supplementary rifampicin was recommended if deep infection was suspected.

Main outcome measures.  Primary end‐points were mortality at 28 days and at 3 months. Clinical and laboratory parameters were analysed as secondary end‐points.

Results.  Adding levofloxacin to the standard treatment offered no survival benefit. Case fatality rates were 14% in both groups at 28 days, and 21% in the standard treatment and 18% in the levofloxacin group at 3 months. Levofloxacin combination did not differ from the standard treatment in the number of complications, time to defervescence, decrease in serum C‐reactive protein concentration or length of antibiotic treatment. Deep infection was found in 84% of patients within 1 week following randomization with no difference between the treatment groups. At 3 months, the case fatality rate for patients with deep infection was 17% amongst those who received rifampicin versus 38% for those without rifampicin (P < 0.001, odds ratio = 3.06, 95% confidence intervals = 1.69–5.54).

Conclusions.  Levofloxacin combined with standard treatment in S. aureus bacteraemia did not decrease mortality or the incidence of deep infections, nor did it speed up recovery. Interestingly, deep infections in S. aureus bacteraemia appeared to be more common than previously reported.
Inhibition of Corticotrophin‐Releasing Hormone Transcription by Inducible cAMP‐Early Repressor in the Hypothalamic Cell Line, 4B
Authors: Liu Y. , Kalintchenko N. , Sassone‐Corsi P. , Aguilera G.
Published: December 2005

We have shown recently that the rapid decline in corticotrophin‐releasing hormone (CRH) transcription following activation by stress is associated with induction and binding to the CRH promoter of the repressor isoforms of cAMP responsive element modulator (CREM), inducible cAMP early repressor (ICER). The ability of ICER to inhibit CRH transcription was examined in the hypothalamic cell line, 4B, which expresses CRH. Co‐transfection of the inhibitory isoforms of CREM, ICER I and II and CREMβ, and CRH promoter‐luciferase constructs in 4B cells blunted basal and forskolin‐stimulated CRH promoter activity, an effect which was abolished by mutation of the CRE of the CRH promoter. Western blot analyses and electromobility gel‐shift and super‐shift showed increases in endogenous ICER after 3 h of incubation with forskolin. Consistent with an inhibitory effect of CREM on CRH transcription, chromatin immunoprecipitation assays in cells transfected with ICER I revealed recruitment of CREM by the CRH promoter in conjunction with decreases in Pol II association. The study shows that generation of ICER following prolonged stimulation with forskolin, or transfection of an ICER expression vector in hypothalamic cell lines expressing CRH, is associated with CREM binding to the CRH promoter and transcriptional repression. The data support the hypothesis that induction of repressor isoforms of CREM is part of an intracellular feedback mechanism contributing to the termination of CRH transcription during stimulation.
Response of fluctuating and directional asymmetry to selection on wing shape in Drosophila melanogaster
Authors: Pélabon C. , Hansen T. F. , Carter A. J. R. , Houle D.
Published: December 2005

We tested whether directional selection on an index-based wing character in Drosophila melanogaster affected developmental stability and patterns of directional asymmetry. We selected for both an increase (up selection) and a decrease (down selection) of the index value on the left wing and compared patterns of fluctuating and directional asymmetry in the selection index and other wing traits across selection lines. Changes in fluctuating asymmetry across selection lines were predominantly small, but we observed a tendency for fluctuating asymmetry to decrease in the up-selected lines in both replicates. Because changes in fluctuating asymmetry depended on the direction of selection, and were not related to changes in trait size, these results fail to support existing hypotheses linking directional selection and developmental stability. Selection also produced a pattern of directional asymmetry that was similar in all selected lines whatever the direction of selection. This result may be interpreted as a release of genetic variance in directional asymmetry under selection.
‘New cartographies’ and the decolonization of European geographies
Authors: Pickles John
Published: December 2005

This paper begins with Jacques Derrida's ‘Europe’ on an‐Other heading and Claudio

Minca's (2003
Environment and Planning D: Society and Space 21 160–8) suggestion that critical human geographers need to become more attentive to their own geographical predispositions and positionalities. The paper focuses on some lessons from postcolonial writing and asks to what extent we have been successful in decolonizing (and reshaping) geographies of Europe in the ways in which we respond to transformations at the borders of Europe. The paper concludes with a discussion of efforts to ‘provincialize’ and decolonize Euro‐geographies, and the kinds of ‘new cartographies’ of Europe we might write and teach.
A review of the reliability of radiographic measurements in estimating alveolar bone changes
Authors: Benn Douglas K.
Published: December 2005

Abstract Despite their widespread use, dental radiographs have numerous shortcomings for measuring alveolar bone changes. In order to develop guidelines for improving the reliability of radiographic measurements, factors affecting the formation of an image were reviewed. These were considered regarding the design of a clinical monitoring system, capable of detecting the loss of small amounts of alveolar bone crest from serial films. Dentists need a monitoring system to assess whether bone loss is progressing or to judge whether a treatment is successful. 2 models were constructed to predict how long it would take to detect marginal bone loss occurring at a linear rate of 0.1 mm/year. The 1st model assumed a CEJ‐crest measurement error of ±0.3 mm and the second ±0.9 mm, both using a 0.1 mm measuring interval. These error values were derived from the literature. The 1st model predicted it would take between 7 and 13 years for the system to measure a 1.0 mm loss in crest height caused by an actual loss of between 0.7 and 1.3 mm. The 2nd model predicted that a 1.0 mm measurement would occur between 1 and 19 years, caused by an actual crestal bone loss of between 0.1 and 1.9 mm. From these models, it appears that routine screening of patients by general dental practitioners for small amounts of bone loss is unlikely to be successful without the use of (i) repositionable stentless film holders to standardise the irradiation geometry, (ii) a very accurate reproducible measuring technique which (iii) will probably require an automatic computer‐based measuring system. Previous reports on the measurement of bone loss less than 1.0 mm are most likely measurement errors. A method of selecting radiographic examination time intervals is suggested.
Dental health behaviors and periodontal disease indicators in Danish youths
Authors: Lissau Inge , Hoist Dorthe , Friis‐Hasché Erik
Published: December 2005

Abstract The purpose of the present study was to analyse the epidemiologic relationship between dental health behaviors and periodontal disease. Indicators of periodontal disease in terms of bleeding and calculus were measured dichotomously (absence/presence). Periodontal pockets were as follows: normal pockets (0–3 mm), shallow pockets (4–5 mm), and deep pockets (6+ mm). The indicators were measured on 4 surfaces on 6 index teeth (16, 11, 26, 36, 31, 46) in 1984–85. The highest value for each tooth of bleeding (0/1), calculus (0/1) and pockets (0/1/2) was used for calculation of the bleeding index, the calculus index and the pocket index. The participation rate in 1984–85 was 86%, and the study population involved 368 males and 388 females. Information concerning dental health behavior was obtained both in childhood (1974) when the individuals were 9–10 years of age, and in adulthood (1984–85) when the individuals were 20–21 years of age. Information concerning dental health behaviors in adulthood, i.e., regularity of dental visits, frequency of tooth brushing, and regular use of interdental aids, was obtained through a self‐administered questionnaire (1984–85). Dental health behaviors in childhood (1974) was operationalized as level of plaque, gingivitis, and dmfs. The results showed that dental health behaviors in childhood and in adulthood were together responsible for 9.4–13.8% of the variance in level of periodontal disease indicators. Determinants of early dental health behaviors in terms of plaque and dmfs at age 9–10 years were significant predictors in pocket index at age 20–21. Furthermore, determinants of dental health behaviors at age 20–21 years, in terms of frequency of toothbrushing, use of dental floss, and regularity of dental visits, were significant predictors in bleeding index and pocket index. In conclusion, dental health behaviors both in childhood and in adulthood were significant predictors of periodontal disease in adulthood.
Changes in subgingival microbiota during puberty
Authors: Gusberti F. A. , Mombelli A. , Lang N. P. , Minder Ch. E.
Published: December 2005

Abstract It was the purpose of the present investigation to monitor the composition of the subgingival microbiota at selected sites in individuals passing through puberty and to correlate observed changes with the development of pubertal maturation. Between the ages of 11 and 14 years, pubertal and skeletal maturation was monitored annually in 22 boys and 20 girls. During this time, subgingival microbial samples were taken every 4th to 5th month (10 times in 4 years) mesially of the upper first molars. High values in total bacterial counts were reached after the onset of puberty, followed by a decrease towards the end of the observation period. The frequency of detection of Actinomyces odontolyticus and of Capnocytophaga sp. increased with time. The frequencies of other selected species, specifically of black pigmenting Bacteroides sp. were not found to increase when tested by linear and quadratic models of time trend. However, a statistically significant rise in the frequency of detecting B. intermedius and B. melaninogenicus was noted in the initial pubertal phase identified by the onset of testicular growth in boys (p= 0.05). A significant relationship also existed between testes growth and increase of A. odontolyticus (p<0.01). In girls, a similar increase was obtained for A. odontolyticus when studied in relation to the Tanner scores for breast development (p<0.01). The changes observed in the subgingival microbiota during puberty may be related to the development of gingivitis, which was demonstrated by a higher tendency for gingival bleeding during the course of the pubertal maturation process.
The effect of triclosan, stannous fluoride and chlorhexidine products on: (I) Plaque regrowth over a 4‐day period
Authors: Addy Martin , Jenkins S. , Newcombe R.
Published: December 2005

Abstract A number of substances have been incorporated into toothpastes or gels to inhibit plaque regrowth. The aim of this study was to evaluate triclosan and stannous fluoride products for plaque inhibitory properties by comparison with a chlorhexidine or saline rinse and a control product which was a conventional commercially available toothpaste. In a blind 8 cell cross‐over study, 15 volunteers rinsed 2 × a day for 4 days with slurries of the products or the saline and chlorhexidine solutions. No other form of oral hygiene was performed and plaque regrowth from a zero baseline was recorded by plaque score and plaque area. Plaque regrowth was significantly less with the chlorhexidine rinse and significantly greater with the saline rinse compared to the toothpaste and gel products. No significant differences were found between the test and control products. The results again demonstrate that commercially available toothpastes have plaque inhibitory effects which so far appear difficult to improve upon by the addition of specific ingredients, in this case stannous fluoride or triclosan. Commercially available products of known activity would appear useful benchmarks for comparison of experimental formulations.
Cementum thickness and mesial drift
Authors: Dastmalchi Rose , Poison Alan , Bouwsma Otis , Proskin Howard
Published: December 2005

Abstract Cementum thickness increases uniformly with age, and questionably from functional stimulation due to tensional forces. Mesial drift of teeth results in tensional forces on distal root surfaces. This study evaluated whether there was any discernible effect on cementum thickness related to mesial drift in humans. The material consisted of maxillary and mandibular bicuspids and molars with their surrounding periodontia from 5 humans (mean age at death, 48.6 years). The teeth and tissues had been sectioned histologically in a mesio‐distal plane, and the analysis for each tooth was done using 3 step‐serial sections from the mid‐buccolingual region. On the mesial and distal surface of each tooth, cementum thickness was measured in μm at 3 defined locations at a level representing the mid‐point of root length for bicuspids and molars. Means from the measurements on mesial and distal surfaces were compared using descriptive and inferential statistical methods. For each individual tooth analyzed, the cementum was thicker on the distal surface (range greater, 32–107%; mean, 69%). The statistical comparisons showed that cementum thickness on the distal surface was significantly greater for bicuspids (mesial, 135 μm: distal, 216 μm), molars (mesial, 154 μm : distal, 284 μm), and all teeth combined (mesial, 154 μm: distal, 284 μm). The magnitude of this difference became greater with increasing age. It was concluded that cementum thickness was markedly greater on the distal surfaces of teeth from adult humans, and that this may be due to functional stimulation from mesial drift over time.
Efficiency of split‐mouth designs
Authors: Hujoel P. P. , Loesche W. J.
Published: December 2005

Abstract The purpose of this paper is (1) to investigate the similarity of the amount, distribution, and, severity of periodontal disease of the within‐patient experimental units, (2) to estimate the relative efficiencies of split‐mouth designs when compared to whole‐mouth designs, and (3) to discuss how stratification on initial pocket depth can result in large differences in the power of the test‐statistics in the different disease categories. Periodontal disease characteristics are not always homogeneously distributed over the within‐patient experimental units and this heterogeneity can reduce the efficiency of split‐mouth designs. In particular, if analyses are stratified on initial pocket depth, sites with an initial probing depth deeper than 6 mm may be small in number and asymmetrically distributed when compared to sites with an initial probing depth less than 6 mm. This may result in large differences of the power of the test statistics among the different disease categories and should lead to a careful interpretation of the statistical significance tests. When disease characteristics are symmetrically distributed over the within‐patient experimental units and a sufficient number of sites is present per experimental unit, the split‐mouth design can provide moderate to large gains in relative efficiency. In the absence of a symmetric disease distribution, wholemouth clinical trials may be preferable.
A 10‐year retrospective study of periodontal disease progression Clinical characteristics of subjects with pronounced and minimal disease development
Authors: Papapanou Panos N. , Wennström Jan L.
Published: December 2005

Abstract The present study reports on some characteristics of 2 groups of subjects, chosen from a sample of 191 dentate individuals who had been exposed to full‐month intraoral radiographic examinations in 1975 and 1985. The 1st group, which comprised 14 subjects, had experienced pronounced loss of periodontal bone support during a 10‐year period (mean longitudinal bone loss of 4.13 mm (S.D. 1.4)). The 2nd group of 14 subjects had suffered no or minimal periodontal disease progression (mean longitudinal bone gain of 0.35 mm (S.D. 0.7)). A clinical examination was performed in conjunction with the radiographic examination in 1985 and included assessment of plaque, gingivitis, bleeding on probing from the base of the pocket, probing depth and probing attachment loss. Information regarding the oral hygiene habits of the subjects as well as the amount of dental and periodontal therapy received between 1975 and 1985 was obtained through a questionnaire. The results revealed that the 14 subjects who had experienced pronounced progression of periodontal disease had more plaque and gingivitis, deeper pockets and more attachment loss than the 14 subjects with minimal periodontal disease progression. Over the 10‐year period, subjects in the “high rate” group had lost a mean of 6.8 teeth (S.D. 5.0) as compared to 4.1 teeth (S.D. 4.4) in the “low rate” group. The radiographic assessments of alveolar bone loss were strongly correlated with the assessments of probing attachment loss (r= 0.80, p= 0.0001). In 92% of the tooth sites examined, the difference between the radiographic and the clinical assessment was within 2 mm. The questionnaire data disclosed that subjects in the 2 groups had similar oral hygiene habits and were subjected to dental treatment equally often. However, subjects in the “high rate” group, claimed to have received a greater amount of periodontal treatment over the 10‐year period than their “low rate” counterparts.
The role of periodontal probing depth in clinical decision‐making
Authors: Persson Rutger , Svendsen John
Published: December 2005

Abstract This retrospective study examines the role of periodontal probing depth in clinical decision‐making. The expected values of no treatment and surgical and non‐surgical therapies were obtained by combining the probability of each treatment outcome and utility values denoting the preference for each outcome. The expected value for non‐surgical therapy was higher for sextants exhibiting a positive response to initial therapy than sextants which did not respond to initial therapy (0.735 versus 0.706). This trend was not observed for sextants treated surgically. Surgical therapy was effective over all levels of disease severity and was the preferred form of therapy with respect to reduction of probing depth except for sextants exhibiting 4 to 5 mm pockets. In this latter situation, the expected value at 3 years for non‐surgical and surgical therapy was 0.795 and 0.792, respectively. Neither form of therapy could consistently achieve periodontal probing depths equal to or less than 3 mm throughout a given sextant. This study facilitates the selection of an optimal therapeutic strategy with respect to periodontal probing depth.
Statistical models for data from periodontal research
Authors: Sterne J. A. C. , Curtis M. A. , Gillett I. R. , Griffiths G. S. , Maiden M. F. J. , Wilton J. M. A. , Johnson N. W.
Published: December 2005

AbstractMany factors have been hypothesised either to characterise groups and individuals at risk for periodontal disease or to be markers of periodontal breakdown. In order to identify these as associated either with disease status or progression, a statistical association between the factor and a measure of disease will have to be demonstrated. The statistical modelling of data arising from periodontal research presents special problems. These include the large number of measurements made in each subject, the large magnitude of measurement error compared to the changes in attachment level, the analysis of longitudinal studies, the lack of a measure of instantaneous rate of attachment loss and controversies over the nature of the progression of the disease. We consider statistical methods currently available in the light of these difficulties and identify areas in which further research is necessary.
Morphological compositions of subgingival microbiota in Actinobacillus actinomycetemcomitans‐ associated periodontitis
Authors: Müller H.‐P. , Müller R.F. , Lange D.E.
Published: December 2005

Abstract Infrequent occurrence of spirochetes and rather low proportions of these organisms have been reported in localized juvenile periodontitis, where periodontal lesions often harbour large numbers of Actinobacillus actinomycetem‐comitans, a suspected principal periopathogen strongly implicated in the patho‐genesis of this and other forms of chronic periodontitis. We studied the association of subgingival A. actinomycetemcomitans with the morphological composition of the subgingival microbiota in a large population of patients suffering from advanced periodontitis. Subgingival plaque from the deepest pockets of every quadrant of their dentitions was sampled and pooled in 70 patients between 14 and 63 years of age, and analysed morphologically by phase‐contrast microscopy. A minimum % similarity index was employed to define 4 clusters with different morphological composition of the floras. The actual proportion of A. actinomycetemcomitans was determined at 2 sites with deep periodontal pockets. All clusters harboured patients infected with A. actinomycetemcomitans. If present, in clusters predominated by motile rods or medium‐sized spirochetes, the organism was found in rather low proportions (median 5.3% and 3.4%, respectively). However, the cluster with a pooled flora mainly consisting of coccoid cells revealed periodontal sites with A. actinomycetemcomitans in proportions of more than 53% (median), if the organism was present (p<0.01). We found a positive correlation between proportions of A. actinomycetemcomitans and cocci(R = 0.65) and negative correlations with spirochetes and motile rods (R=−0.61, R=−0.59, respectively). Cautious interpretation of subgingival plaque predominated by coccoid cells is recommended, if deep periodontal pockets and obvious signs of inflammation are present, since these pockets were found to be often infected with large numbers of A. actinomycetemcomitans.
A 6‐year study on the pattern of periodontal disease progression
Authors: Albandar Jasim M.
Published: December 2005

Abstract. The present longitudinal radiographic investigation was designed to study the change in the alveolar bone height over 6 years in relation to tooth type, age and the presence of previous bone loss in a group of 142 subjects (age 18–67 years) who were not under systematic periodontal treatment. The subjects were examined radiographically at baseline, and after 2 and 6 years, and sites showing significant (≥ 1 mm) change in the alveolar bone height during 2 consecutive examinations were identified. 90.2% of all examined sites showed no bone loss during the 6 years, while 8.6% and 1.2% of the sites exhibited bone loss during one or both examination periods, respectively, 3 groups of subjects within the studied population were identified. Approximately 5% of the subjects had high rates of periodontal disease progression whilst ∼ 70% demonstrated very few or no sites with bone loss, and ∼ 25% had a moderate level of disease progression during the study period. The results also showed that the number of sites exhibiting alveolar bone loss during the study period varied with respect to tooth type, age of the patient and presence of bone loss at baseline. In addition, significantly different rates of bone loss were disclosed with relation to tooth type (P<0.01), age (P<0.0001) and initial bone loss (P<0.01). It was concluded that periodontal disease progression occurs infrequently and may take the form of discrete or recurrent episodes of loss of periodontal support which can be influenced by the location of the site, age of the subject and previous periodontal disease experience.
Periodontal aspects of osseointegrated fixtures supporting an overdenture
Authors: Quirynen M. , Naert I. , van Steenberghe D. , Teerlinck J. , Dekeyser C. , Theuniers G.
Published: December 2005

Abstract 196 BrånemarkTM implants in 86 consecutive patients rehabilitated by means of overdentures (6 upper jaws, 80 lower jaws) were observed longitudinally. In each jaw, only 2 implants were used to anchor the overdenture. 2 implants in the lower jaw showed some mobility at the abutment installation and were removed immediately. During the loading period (mean loading time 19.1 months ranging from 4 to 48 months), none of the implants showed any signs of non‐integration. The marginal tissue reaction and plaque accumulation were monitored using conventional indices. Clinical methods and standardized radiographs were used to evaluate the bone level and density. The numbers of approximal surfaces without plaque (40%) or with gingival inflammation (55%) were almost constant throughout the study. The probing pocket depths remained within the range of 2.7 to 3.2 mm during the observation time, whereas the distance of the gingival margin from the top of the abutment clearly increased (from 1.8 to 2.9 mm). For loaded lower jaw implants connected to each other with a straight bar, a radiographic bone loss of 0.8 mm was observed during the first postsurgical year followed by a mean annual bone loss of less than 0.1 mm. For the “sleeping” fixtures, 50% less bone loss was recorded. For loaded but not interconnected implants in the upper jaw, the bone loss during the first 6 months reached 2.0 mm. The loss in marginal bone height did not clearly correlate with parameters such as the plaque index, the gingivitis index, the presence or absence of gingiva around the abutment, or the implant length. The present data, with an observation time up to 4 years, showed that the failure rate for BrånemarkTM implants supporting overdentures in the lower jaw can be limited to 1%. However, the use of 2 unconnected fixtures in the upper jaw cannot presently be advocated since considerable bone loss was observed.