bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of slip on asperities: Numerical simulation of seismic cycles on a two‐dimensional planar fault with nonuniform frictional property
Authors: Kato Naoyuki
Published: December 2004

Numerical simulation is conducted to understand the variety of frictional sliding on a plate interface and complex recurrence of earthquakes. A planar square fault in an infinite uniform elastic medium is considered, and the frictional stress on the fault is assumed to obey a rate‐ and state‐dependent friction law. Nonuniformity in a frictional constitutive parameter is introduced on the model fault. On the fault plane, one or two circular patches with velocity‐weakening frictional property are surrounded by velocity‐strengthening areas. Unstable slip may occur for velocity‐weakening friction and aseismic sliding occurs for velocity‐strengthening friction. Velocity‐weakening patches correspond to asperities because intense seismic slip may occur there. Simulation results indicate that episodic aseismic slip events (slow earthquakes) occur when the velocity‐weakening patch size is close to the critical size of earthquake nucleation. Propagation of postseismic sliding on the velocity‐strengthening region follows an earthquake at a velocity‐weakening patch. When the postseismic sliding reaches another velocity‐weakening patch, an earthquake may be triggered at the patch, resulting in a double earthquake. The time delay between two events of the double earthquake increases with the distance between the two velocity‐weakening patches or the degree of velocity strengthening in the region between the patches. When the distance between the two velocity‐weakening patches is long, an earthquake at one patch does not directly cause an earthquake at the other patch. In these cases, complex earthquake recurrence may appear due to the interaction between ruptures at the two patches, and the recurrence interval of earthquakes and coseismic slip is not constant at each velocity‐weakening patch.
Subduction zone coupling and tectonic block rotations in the North Island, New Zealand
Authors: Wallace Laura M. , Beavan John , McCaffrey Robert , Darby Desmond
Published: December 2004

The GPS velocity field in the North Island of New Zealand is dominated by the long‐term tectonic rotation of the eastern North Island and elastic strain from stress buildup on the subduction zone thrust fault. We simultaneously invert GPS velocities, earthquake slip vectors, and geological fault slip rates in the North Island for the angular velocities of elastic crustal blocks and the spatially variable degree of coupling on faults separating the blocks. This approach allows us to estimate the distribution of interseismic coupling on the subduction zone interface beneath the North Island and the kinematics of the tectonic block rotations. In agreement with previous studies we find that the subduction zone interface beneath the southern North Island has a high slip rate deficit during the interseismic period, and the slip rate deficit decreases northward along the margin. Much of the North Island is rotating as several, distinct tectonic blocks (clockwise at 0.5–3.8 deg Myr−1) about nearby axes relative to the Australian Plate. This rotation accommodates much of the margin‐parallel component of motion between the Pacific and Australian plates. On the basis of our estimation of the block kinematics we suggest that rotation of the eastern North Island occurs because of the southward increasing thickness of the subducting Hikurangi Plateau. These results have implications for our understanding of convergent margin plate boundary zones around the world, particularly with regard to our knowledge of mechanisms for rapid tectonic block rotations at convergent margins and the role of block rotations in the slip partitioning process.
Comet 81P/Wild 2 size, shape, and orientation
Authors: Duxbury Thomas C. , Newburn Ray L. , Brownlee Donald E.
Published: December 2004

Spectacular images, taken during the flyby of 81P/Wild 2 by the NASA Stardust spacecraft, were used to determine that the shape of the comet 81P/Wild 2 nucleus can be reasonably modeled as a triaxial ellipse having radii 1.65 × 2.00 × 2.75 km ± 0.05 km (1σ). The shortest axis, considered the rotational axis, has a right ascension of 110° and a declination of −13°. The longest axis, used to define zero longitude, has an argument of prime meridian angle of 155°. All angles use the IAU definitions, are relative to the Earth Mean Equator and Vernal Equinox of J2000 and have uncertainties of ±3° (1σ). The rotational axis was pointed 65° from the sun during the Stardust encounter of 81P/Wild 2, making an area within 25° of the spin axis in continual sunlight and the apparent source of a few major jets.
The dust mass distribution of comet 81P/Wild 2
Authors: Green S. F. , McDonnell J. A. M. , McBride N. , Colwell M. T. S. H. , Tuzzolino A. J. , Economou T. E. , Tsou P. , Clark B. C. , Brownlee D. E.
Published: December 2004

The Dust Flux Monitor Instrument (DFMI) made direct measurements of the dust environment in the mass range 10−14 < m < 10−5 kg at comet 81P/Wild 2 during the Stardust flyby on 2 January 2004. We describe the techniques for derivation of the particle mass distribution, including updated calibration for the acoustic subsystem. The dust coma is characterized by “swarms” and “bursts” of particles with large variations of flux on small spatial scales, which may be explained by jets and fragmentation. The mass of the dust coma is dominated by larger particles, as was found for comets 1P/Halley and 26P/Grigg‐Skjellerup. However, almost 80% of the particles were detected many minutes after closest approach at a distance of ∼4000 km, where small grains dominated the detected mass flux. The mass distribution varies on small spatial scales with location in the coma, consistent with the jets and fragmentation inferred from the highly heterogeneous dust spatial distribution. The cumulative mass distribution index α (where the number of particles of mass m or larger, N(m) ∝ m−α) in the coma ranges from 0.3 to 1.1. It is possible that jets and fragmentation occur in all comets but have not previously been well observed due to the limitations of detectors and flyby geometry. We estimate that 2800 ± 500 particles of diameter 15 μm or larger impacted the aerogel collectors, the largest being ∼6 × 10−7 kg (diameter ∼1 mm), which dominates the total collected mass. Of these, only 500 ± 200, representing just 3% of the collected mass, originated in the far postencounter region.
Interfacial area measurements for unsaturated flow through a porous medium
Authors: Culligan Katherine A. , Wildenschild Dorthe , Christensen Britt S. B. , Gray William G. , Rivers Mark L. , Tompson Andrew F. B.
Published: December 2004

Multiphase flow and contaminant transport in porous media are strongly influenced by the presence of fluid‐fluid interfaces. Recent theoretical work based on conservation laws and the second law of thermodynamics has demonstrated the need for quantitative interfacial area information to be incorporated into multiphase flow models. We have used synchrotron based X‐ray microtomography to investigate unsaturated flow through a glass bead column. Fully three‐dimensional images were collected at points on the primary drainage curve and on the secondary imbibition and drainage loops. Analysis of the high‐resolution images (17 micron voxels) allows for computation of interfacial areas and saturation. Corresponding pressure measurements are made during the course of the experiments. Results show the fluid‐fluid interfacial area increasing as saturation decreases, reaching a maximum at saturations ranging from 20 to 35% and then decreasing as the saturation continues to zero. The findings support results of numerical studies reported in the literature.
The I allele of the angiotensin‐converting enzyme gene is associated with an increased percentage of slow‐twitch type I fibers in human skeletal muscle
Authors: Zhang B , Tanaka H , Shono N , Miura S , Kiyonaga A , Shindo M , Saku K
Published: December 2004

The insertion (I) allele of the human angiotensin‐converting enzyme (ACE) gene is associated with lower serum and tissue ACE activity, and with greater endurance performance and enhanced mechanical efficiency of trained muscle. We tested the hypothesis that the ACE‐I allele may be associated with increased slow‐twitch fiber, which is more efficient than fast‐twitch fiber in low‐velocity contraction, by examining the association between the ACE genotype and skeletal muscle fiber (SMF) types in 41 untrained healthy young volunteer subjects (31 males, 10 females, age 24 ± 3 years). Skeletal muscle samples were taken from the left vastus lateralis using the needle‐biopsy method. Slow‐twitch type I fibers and fast‐twitch type IIa and IIb fibers were classified histochemically based on staining for myosin adenosine triphosphatase (ATPase) activity at different pH values. Amylase‐periodic acid‐Schiff staining was used to visualize capillaries around fibers. ACE‐II subjects had significantly (p < 0.01) higher percentages of type I fibers (50.1 ± 13.9%vs 30.5 ± 13.3%) and lower percentages of type IIb fibers (16.2 ± 6.6%vs 32.9 ± 7.4%) than ACE‐DD subjects. The linear trends for decreases in type I fibers and increases in type IIb fibers from ACE‐II → ID → DD genotypes were significant as assessed by an analysis of variance. The ratio of type I:II fibers also differed according to the ACE genotype. A multivariate logistic regression analysis showed that the ACE‐I allele had significant additive and recessive (codominant) effects on the increased type I fibers and the ratio of type I:II fibers. No specific pattern of capillarization was observed among the three ACE genotypes. In conclusion, the ACE‐I allele was associated with increased type I SMF, which may be a mechanism for the association between the ACE genotype and endurance performance.
Landmarks in genetics through philately: the tools used by dysmorphologists
Authors: Chudley AE
Published: December 2004

This essay liberally uses stamps from around the world to illustrate the many tools at the disposal of clinical geneticists and dysmorphologists. The tools begin with the construction of a family tree and eventually lead to the utilization of computers and the Internet as important diagnostic resources.
Mutation analysis of Connexin 31 (GJB3) in sporadic non‐syndromic hearing impairment
Authors: Mhatre AN , Weld E , Lalwani AK
Published: December 2004

Mutations in GJB3, the gene encoding the gap junction protein Connexin 31 (CX31), have been pathogenically linked to erythrokeratodermia and non‐syndromic autosomal dominant (DFNA2) or recessive hereditary hearing impairment (HHI). To determine the contribution of CX31 to sporadic deafness, we assessed 63 individuals with non‐syndromic hearing impairment for CX31 mutations. Single coding exon of CX31 was amplified from genomic DNA and then sequenced. Single nucleotide sequence alteration was present in 15 out of 63 patients (24%), all of the positives being heterozygous for the four different single base pair changes that were detected: C94T, C201T, C357T and C798T. Of these, only C94T transition, identified in two patients, results in amino acid change, R32W, while the other three changes are single nucleotide polymorphisms (SNPs). The R32W substitution in CX31 has been previously documented and is speculated to manifest variable penetrance, similar to the polymorphic allele encoding CX26M34T. Over one‐third of all samples were also screened with denaturing high‐performance liquid chromatography (dHPLC). Seven out of 25 individuals screened were determined to be positive for CX31 sequence variation. Sequence analysis of the 25 individuals screened identified nucleotide alterations in all of the 7 ‘positives’ and in none of the 16 ‘negatives’ yielding a specificity and sensitivity of 100%. Thus, dHPLC represents a highly efficient CX31 screening technique. This study suggests that while sequence alterations are common, pathogenic mutations of CX31 are infrequent in sporadic non‐syndromic hearing impairment.
Genetic counseling for prostate cancer risk
Authors: Nieder AM , Taneja SS , Zeegers MPA , Ostrer H
Published: December 2004

Nieder AM, Taneja SS, Zeegers MPA and Ostrer H. Genetic counseling for prostate cancer risk.

Clin Genet 2003: 63 169‐176. © Blackwell Munksgaard, 2003

Major risk factors for developing prostate cancer, including positive family history and African–American ethnicity, can be quantified for genetic counseling. Factors increasing familial risk for prostate cancer are closer degree of kinship, number of affected relatives, and early age of onset (< 50 years) among the affected relatives. Genetic testing may be useful for modification of risk, but currently should be performed only within the context of a well‐designed research study that will determine penetrance and genotype–phenotype correlation of specific mutations. Even in the absence of genetic testing, African–American men and men with a strong family history of prostate cancer may opt to initiate screening by prostate specific antigen (PSA) and digital rectal exam (DRE) screening at age 40.
Identification of a deletion in the mismatch repair gene, MSH2, using mouse–human cell hybrids monosomal for chromosome 2
Authors: Pyatt RE , Nakagawa H , Hampel H , Sedra M , Fuchik MB , Comeras I , De La Chapelle A , Prior TW
Published: December 2004

Hereditary non‐polyposis colorectal cancer is characterized by mutations in one of the DNA mismatch repair genes, primarily MLH1, MSH2, or MSH6. We report here the identification of a genomic deletion of ≈ 11.4 kb encompassing the first two exons of the MSH2 gene in two generations of an Ohio family. By Southern blot analysis, using a cDNA probe spanning the first seven exons of MSH2, an alteration in each of three different enzyme digests (including a unique 13‐kb band on HindIII digests) was observed, which suggested the presence of a large alteration in the 5′ region of this gene. Mouse–human cell hybrids from a mutation carrier were then generated which contained a single copy each of human chromosome 2 on which the MSH2 gene resides. Southern blots on DNA from the cell hybrids demonstrated the same, unique 13‐kb band from one MSH2 allele, as seen in the diploid DNA. DNA from this same monosomal cell hybrid failed to amplify in polymerase chain reactions (PCRs) using primers to exons 1 and 2, demonstrating the deletion of these sequences in one MSH2 allele, and the breakpoints involving Alu repeats were identified by PCR amplification and sequence analysis.
Ehlers–Danlos syndrome type IV: unusual congenital anomalies in a mother and son with a COL3A1 mutation and a normal collagen III protein profile
Authors: Kroes HY , Pals G , Van Essen AJ
Published: December 2004

A mother and son with Ehlers–Danlos syndrome (EDS) type IV and unusual congenital anomalies are described. The congenital anomalies include, in the mother, amniotic band‐like constrictions on one hand, a unilateral clubfoot, and macrocephaly owing to normal‐pressure hydrocephaly and, in the son, an esophageal atresia and hydrocephaly. Protein analysis of collagen III in cultured fibroblasts of the mother showed no abnormalities. However, DNA analysis of the COL3A1 gene revealed a pathogenic mutation (388G→T) in both the mother and the son. The possible relationship between the observed congenital anomalies and EDS IV are discussed. We stress that DNA analysis of COL3A1 should be performed in all patients when there is a strong suspicion of EDS IV, despite negative findings in a collagen protein analysis.
Genetic heterogeneity for a Nijmegen breakage‐like syndrome
Authors: Maraschio P , Spadoni E , Tanzarella C , Antoccia A , Di Masi A , Maghnie M , Varon R , Demuth I , Tiepolo L , Danesino C
Published: December 2004

Nijmegen breakage syndrome (NBS) is a rare, autosomal‐recessive chromosome instability disorder characterized by growth and developmental defects, immunodeficiency, high susceptibility to lymphoid malignancies, hypersensitivity to ionizing radiation and aberrant cell‐cycle checkpoint control. The disease is caused by mutations in the NBS1 gene, which encodes nibrin, a component of the hMre11–Rad50–p95 complex involved in cellular response to DNA double‐strand breaks. Genetic heterogeneity has been suggested in at least two patients with the NBS phenotype, but no mutation in the NBS1 gene; recently, mutations in the gene encoding the enzyme ligase IV have been identified in patients with signs of NBS. We describe a boy with an NBS clinical phenotype but no mutation in either the NBS1 or the LIG4 genes. The analysis of his cellular phenotype reveals chromosome instability and radiosensitivity, but normal cell‐cycle checkpoint control. In addition, a literature review was carried out to summarize and compare data of all NBS‐like patients reported to date. This case confirms genetic heterogeneity for NBS. We believe that dissecting the clinical and cellular phenotypes of this and other NBS‐like patients will provide useful information for the research of new genes involved in cellular response to DNA damage and the assessment of cancer risk in NBS‐like syndrome.
The developing heart and congenital heart defects: a make or break situation
Authors: Bruneau BG
Published: December 2004

Congenital heart defects are common in humans, but the underlying basis for these defects is not well understood. It has been clear that abnormal heart development is at the root of these diseases, but the genes involved have remained elusive until recently. This review focuses on recent advances in our understanding of mammalian heart formation, and how some of these processes, when disrupted, lead to congenital heart defects.
Osseointegration of endosseous ceramic implants after postoperative low‐power laser stimulation: an in vivo comparative study
Authors: Guzzardella Gaetano A. , Torricelli Paola , Nicoli‐Aldini Nicolò , Giardino Roberto
Published: December 2004

Stimulation with low‐power laser (LPL) can enhance bone repair as reported in experimental studies on bone defects and fracture healing. Little data exist concerning the use of LPL postoperative stimulation to improve osseointegration of endosseous implants in orthopaedic and dental surgery. An in vivo model was used for the present study to evaluate whether Ga–Al–As (780 nm) LPL stimulation can improve biomaterial osseointegration. After drilling holes, cylindrical implants of hydroxyapatite (HA) were placed into both distal femurs of 12 rabbits. From postoperative day 1 and for 5 consecutive days, the left femurs of all rabbits were submitted to LPL treatment (LPL group) with the following parameters: 300 J/cm2, 1 W, 300 Hz, pulsating emission, 10 min. The right femurs were sham‐treated (control group). Three and 6 weeks after implantation, histomorphometric and microhardness measurements were taken. A higher affinity index was observed at the HA–bone interface in the LPL group at 3 (P<0.0005) and 6 weeks (P<0.001); a significant difference in bone microhardness was seen in the LPL group vs. the control group (P<0.01). These results suggest that LPL postoperative treatment enhances the bone–implant interface.
Healing of human extraction sockets filled with Bio‐Oss®
Authors: Carmagnola Daniela , Adriaens Patrick , Berglundh Tord
Published: December 2004

Abstract:  The aim of this study was to investigate the healing of human extraction sockets filled with Bio‐Oss® particles (Geistlich Pharma AG, Wolhusen, Switzerland). In 21 subjects, providing a total of 31 healing sites, at least one tooth was scheduled for extraction and the extraction sites for implant therapy. The dimensions of the alveolar ridge at the extraction sites were considered insufficient and required augmentation concomitant with tooth extraction. There were three treatment groups. In group A, the extraction sockets were covered with a Bio‐Gide® membrane (Geistlich Pharma AG) and in group B the extraction sockets were filled with Bio‐Oss®. The extraction sockets in group C were left to heal spontaneously. Biopsies from the extraction sites were collected at the time of implant installation. Samples from group A showed large amounts of lamellar bone and bone marrow and small proportions of woven bone. Sites grafted with Bio‐Oss® (group B) were comprised of connective tissue and small amounts of newly formed bone surrounding the graft particles. Only 40% of the circumference of the Bio‐Oss® particles was in contact with woven bone. Sites from group C were characterized by the presence of mineralized bone and bone marrow.
Instrument for extraction socket measurement in immediate implant installation
Authors: Juodzbalys Gintaras
Published: December 2004

Abstract: The aim of the present study was to create an instrument and a computer program for measurement of extraction sockets and for planning of the immediate replacement of teeth using screw‐shaped dental implants. Ten titanium screw‐shaped Osteofix Dental Implant System implants (Osteofix, Oulu, Finland) were immediately installed after extraction in nine patients, four women and five men (age 17–62 years). The measurements of fresh extraction sockets were taken at six points (mesio‐buccal, buccal, disto‐buccal, disto‐lingual, lingual and mesio‐lingual) using an instrument created by the author. The area of no contact between bone and dental implant was 11–40% (mean 31%, SD 9%), calculated by computer program. If less than 30% of the implant surface area would be in contact with the bone, immediate replacement was abandoned because sufficient primary stability could not be achieved. Guided bone regeneration was promoted by covering the implant and bone defect with deproteinized bovine bone mineral (Bio‐Oss®, Geistlich AG, Wolhusen, Switzerland) and bioresorbable collagen membrane (Bio‐Gide®, Geistlich AG), fixed in place with resorbable pins (Resor Pin®, Geistlich AG). After 6 months a considerable, statistically significant (P < 0.05) defect reduction of 90% (SD 7%) was noted. It was concluded that an instrument and a computer program created for extraction socket measurement are useful in some borderline cases when there is lack of bone and the success of one‐stage implantation is doubtful.
Laminin‐5 γ2‐chain and collagenase‐2 (MMP‐8) in human peri‐implant sulcular fluid
Authors: Kivelä‐Rajamäki Marjo J. , Teronen Olli P. , Maisi Päivi , Husa Ville , Tervahartiala Taina I. , Pirilä Emma M. , Salo Tuula A. , Mellanen Liisa , Sorsa Timo A.
Published: December 2004

Abstract: Laminin‐5 (LN‐5) is an important epithelial cell‐derived structural and adhesive component in hemidesmosomes and basement membranes (BM). In peri‐implant tissue, gingival BM underlies the junctional epithelium (JE) and reflects the peri‐implant health. Matrix metalloproteinase‐8 (MMP‐8 or collagenase‐2) is one of the key mediators of periodontal tissue destruction. Western immunoblotting with image analysis was used to quantitate the molecular forms of LN‐5 γ2‐chain and MMP‐8 in peri‐implant sulcular fluid (PISF) from healthy and diseased implants. These observations were related to the recorded gingival (GI) and bone resorption (BR) indices of the studied sites. Altogether, 72 PISF samples from osseointegrated dental implants were examined. Significantly elevated levels of fragmented LN‐5 γ2‐chain species (45 and 70 kDa) and MMP‐8 immunoreactivities were observed in diseased PISF in relation to healthy PISF. The elevated levels of both LN‐5 γ2‐chain 45 and 70 kDa fragments and MMP‐8 in diseased PISF from peri‐mucositis (BR = 0) and peri‐implantitis (BR ≥ 1) lesions strongly correlated with elevated GI. Low levels – almost comparable to those seen in healthy control PISF – were seen in PISF from peri‐implantitis lesions (BR ≥ 1) with no GI. Activation of 75 kDa neutrophil (PMN)‐type proMMP‐8 to 10 kDa lower‐molecular‐size active forms was especially detected in PISF from peri‐implantitis with elevated GI. These cross‐sectional findings indicate that elevated MMP‐8 and LN‐5 γ2‐chain fragment levels in PISF can reflect the active phase of the inflammatory peri‐implant disease. Longitudinal studies are required to assess their use, either alone or in combination as molecular biochemical PISF markers, to predict the risk of progression of peri‐implantitis, as well as to monitor the impact of treatment of the disease.
Pathologic interactions in pulpal and periodontal tissues
Authors: Zehnder M. , Gold S. I. , Hasselgren G.
Published: December 2004

Both endodontic and periodontal disease are caused by a mixed anaerobic infection. The pathways for the spread of bacteria between pulpal and periodontal tissues have been discussed with controversy. This article is an attempt to provide a rational approach to the perio‐endo/endo‐perio question based on a review of the relevant literature. In the light of evidence, clinical concepts for the diagnosis and treatment of lesions involving both periodontal and pulpal tissues are discussed.
Effectiveness of an electrically active brush in the removal of overnight plaque and treatment of gingivitis
Authors: Van Der Weijden G. A. , Timmerman M. F. , Piscaer M. , Snoek I. , Van Der Velden U. , Galgut P. N.
Published: December 2004

Objectives: The purpose of the present study was to evaluate the effect of an electrically active toothbrush on established plaque and gingivitis in a 7‐month clinical trial.

Material and methods: For this study, 66 volunteers (non‐dental University students) were selected on the basis of having moderate gingival inflammation. At baseline, plaque (Quigley & Hein), bleeding upon marginal probing and the Modified Gingival index were assessed on the vestibular, mesio‐vestibular, disto‐vestibular and lingual surfaces at four sites per tooth. Subjects were randomly divided among two groups; one group brushed with a control brush (Butler® GUM 309) while the other used the electrically active test brush. After 2 weeks, 4 weeks, 4 months and 7 months the clinical indices were again recorded. At each assessment the participants received a new brush head for the electrically active brush (test group) or a new manual control toothbrush (control group).

Results: All baseline indices appeared to be well balanced. A mean Quigley & Hein plaque score of 1.98 and 2.13 was found in the control and test group, respectively. Little change was observed from baseline to 7 months. The mean bleeding upon marginal probing score at baseline was 0.62 for the control group and 0.59 for the test group. Little to no improvement was observed for the manual brush, whereas an increase in bleeding was observed in the test group in the course of this study. The mean percent reduction in plaque after 1 min of brushing varied throughout the study between 36% and 46%. No difference between the brushes was observed at any time point during the 7‐month test period.

Conclusion: No beneficial effect could be shown for the ‘electrically active design feature’ compared to a regular manual toothbrush control.
A rare case of gingival myiasis caused by Diptera (Calliphoridae)
Authors: Gursel Mihtikar , Aldemir Osman Selçuk , Ozgur Zübeyde , Ataoglu Tamer
Published: December 2004

Myiasis was first described by Hope in 1840. Since then, many cases of myiasis affecting different human organs have been reported. Oral myiasis is very rare in healthy persons but occurs mainly in the tropics and associated with inadequate public and personel hygiene. In this case report, we present clinical findings gingival myiasis. The patient was 26‐year‐old farmer and his chief complaint was discomfort and swelling in his maxillary gingiva. The patient's medical and family histories were non‐contributory and oral hygiene was not acceptable. The diagnosis was based on the characteristic clinical features and the visual presence of wriggling larvae about 1 cm in size. The larvae were identified as Calliphoridae. Treatment consisted of removal of the maggots from the gingival sulcus, followed by scaling and oral hygiene instruction. One week later, a periodontal flap operation was done. The patient was followed‐up for 6 months and healing was uneventful.
Deproteinized bovine bone (Bio‐Oss®) and bioactive glass (Biogran®) arrest bone formation when used as an adjunct to guided tissue regeneration (GTR)
Authors: Stavropoulos Andreas , Kostopoulos Lambros , Nyengaard Jens Randel , Karring Thorkild
Published: December 2004

Objectives:  Grafting of deproteinized bovine bone or bioactive glass has been suggested as an adjunct to guided tissue regeneration (GTR) for the treatment of periodontal and peri‐implant bone defects but the influence of these materials on bone formation is not clarified. The aim of the study was to examine the long‐term influence of deproteinized bovine bone (Bio‐Oss®) or bioactive glass (Biogran®) on bone formation produced by GTR.

Material and Methods:  Eighteen rats were used. Following incisions along the inferior border of the mandible, muscle‐periosteal flaps were raised to expose the mandibular ramus. Rigid, hemispherical, Teflon capsules (6 mm internal diameter and 1 mm peripheral collar) loosely packed with a standardized quantity of either deproteinized bovine bone (test group 1) or bioactive glass (test group 2), or empty capsules (control group) were then placed with their open part facing the lateral surface of the ramus (one capsule per animal). After 1 year, the capsules were removed by a reentry operation, and the animals were sacrificed. Histological specimens of the augmented sites were prepared, and the volumes of (1) newly formed bone, (2) graft particles, and (3) soft connective tissue in the space originally created by the capsule were estimated by a point‐counting technique in three to four histological sections, taken by uniformly random sampling.

Results:  Limited bone formation was observed in the two test groups. The major part of the space originally created by the capsules was occupied by graft particles embedded in connective tissue. The mean volume of newly formed bone occupied only 23% of the total space in the animals grafted with Bio‐Oss® and 12.6% in those grafted with Biogran®. In the control animals, however, 88.2% (p<0.01) of the space was filled with newly formed bone. There were no signs of ongoing bone formation in any of the three experimental groups.

Conclusion:  It is concluded that grafting of Bio‐Oss® or Biogran® as an adjunct to GTR arrests bone formation.
Delayed neutrophil apoptosis in chronic periodontitis patients
Authors: Gamonal J. , Sanz M. , O'Connor A. , Acevedo A. , Suarez I. , Sanz A. , Martínez B. , Silva A.
Published: December 2004

Background, aims: Neutrophil cells constitute the first defense barrier against the oral bacterial challenge in the periodontium. Reduction of neutrophils could impair this response against periopathogenic bacteria such as Porphyromonas gingivalis. Our previous work implicates the apoptosis of neutrophils in the pathogenesis of periodontitis. We now demonstrate that granulocyte monocyte‐colony stimulating factor (GM‐CSF) present in the gingival crevicular fluid (GCF) and secreted during the immune response reduces the apoptosis of neutrophils.

Method: In this study, the presence of GM‐CSF and tumor necrosis factor‐alpha (TNF‐α) in GCF was determined in samples obtained from adult patients with periodontitis and from control subjects with clinically healthy gingiva. GCF was collected for 30 s using Periopaper® strips, and cytokines were quantified by ELISA. We used ex vivo culture of gingival tissue biopsies for 2 and 4 days in the presence of GM‐CSF. Apoptosis was determined using the terminal TdT‐mediated dUTP‐biotin nick end labeling (TUNEL) technique, and expression of Bax by immunohistochemistry.

Results: The presence of GM‐CSF and TNF‐α was detected in the majority of sites from periodontal patients (83.3% and 63.3%, respectively), presenting a total amount of 27.65 and 42.38 pg, respectively. GM‐CSF reduces the neutrophil apoptosis determined by double staining with TUNEL and myeloperoxidase and by a reduction of Bax expression.

Conclusions: These findings suggest a novel mechanism by which neutrophils specifically accumulate in adult patients with periodontitis.
Comparison of body composition and periodontal disease using nutritional assessment techniques: Third National Health and Nutrition Examination Survey (NHANES III)
Authors: Wood Nelson , Johnson Roger B. , Streckfus Charles F.
Published: December 2004

Objectives: The objective of this study was to investigate the association of body composition (obesity) and periodontal disease using simple, inexpensive nutritional assessment techniques available in the Third National Health and Nutrition Examination Survey (NHANES III).

Material and Methods: Caucasian subjects, aged 18 years and above, participating in NHANES III, were used for this study. Weight, height, waist circumference, hip circumference, skinfold thickness (S), and bioelectrical impedance analysis measurements were performed and used in the calculation of body mass index (BMI), waist‐to‐hip ratio (WHR) (visceral fat), log sum of S (subcutaneous fat), and fat‐free mass (FFM). Data were analyzed using SPSS®. One‐way, factorial ANOVA, multivariate analyses, and regression curve analyses were performed. p<0.05 was used to reject the null hypothesis.

Results: Adjusting for age, gender, history of diabetes, current smoking, and socioeconomic status, statistically significant correlations were found between periodontitis and WHR, BMI, FFM, and in some instances S.

Conclusion: This study, indicating significant correlations between body composition and periodontal disease (with WHR being the most significant, followed by BMI, FFM, and S), showed similarities to those observed in other obesity‐related health problems. This strengthened arguments that periodontal disease and certain obesity‐related systemic illnesses are related, with abnormal fat metabolism possibly being an important factor.
Effects of specific nutrients on periodontal disease onset, progression and treatment
Authors: Neiva Rodrigo F. , Steigenga Jennifer , Al‐Shammari Khalaf F. , Wang Hom‐Lay
Published: December 2004

Objectives: The aim of this paper is to review the available literature pertaining to the effects of specific nutritional elements (e.g. vitamin B‐complex, vitamin C and dietary calcium) on general wound healing, periodontal disease status and response to periodontal therapy.

Methods: Critical appraisal of various studies that have evaluated the effects of calcium, ascorbic acid and vitamin B‐complex in wound healing and periodontal treatment.

Results: Periodontal disease onset, progression and response to therapeutic interventions have been shown to be influenced by several systemic, local and environmental modifying factors. Nutritional supplementation has been suggested as a possible influencing factor on periodontal status and wound healing. Several studies have reported various degrees of association between nutritional elements/supplements and periodontal status, and others have reported possible positive influences of nutritional supplementation on periodontal therapeutic outcomes. Future research needs to more fully explore the presence and strength of association between nutrition and periodontal health.

Conclusions: Data collected from the literature suggests that nutrient supplementation causes minimal or no side effects. However, the efficacy of prophylactic nutrient supplementation for the prevention of the onset and progression of periodontal disease, or for the enhancement of periodontal wound healing, remains to be determined.
Herpesviral–bacterial interactions in aggressive periodontitis
Authors: Kamma Joanna J. , Slots Jørgen
Published: December 2004

Background: Human cytomegalovirus, Epstein‐Barr virus and herpesvirus co‐infections occur with significantly higher frequency in actively progressing than in stable periodontitis sites of adolescents and young adults. Also, periodontal presence of cytomegalovirus and Epstein‐Barr virus is associated with increased occurrence of subgingival Porphyromonas gingivalis, Bacteroides forsythus, Dialister pneumosintes, Prevotella intermedia, Prevotella nigrescens, Treponema denticola and Actinobacillus actinomycetemcomitans.

Aim: This article reviews the evidence linking herpesviruses to the development of aggressive periodontitis and suggests a potential mechanism for herpesviral acceleration of the periodontal disease process.

Conclusions: It seems to be a reasonable supposition that the etiopathogenesis of various types of aggressive periodontitis includes the combined action of herpesviruses and specific bacterial species. New vaccines and vaccination technologies that are being developed against herpesviruses warrant testing for their ability to induce a protective immune response against destructive periodontal disease. Clearly, the importance of combined herpesviral‐bacterial infections and associated host responses in the development of periodontitis needs to be studied further.
Are there differences in oral health and oral health behavior between individuals with high and low dental fear?
Authors: Schuller Annemarie A. , Willumsen Tiril , Holst Dorthe
Published: December 2004

Abstract –  Epidemiological studies of the relationship between dental fear, use of dental services, and oral health in different age groups in a common population are scarce. Dental fear and its relationships are usually described in individuals with high dental fear only. The purposes of this study were to describe the prevalence of dental fear in the Norwegian adult population according to age, and to explore differences in oral health, oral hygiene, and visiting habits between individuals with high and low dental fear. For the present study, data from the Trøndelag‐94 study were used. The prevalence of dental fear in our study population of adults in Trøndelag, Norway was 6.6%. There was a tendency for individuals with high dental fear to engage in avoidance behavior more frequently than the low dental fear group. Individuals with high dental fear had a statistically significantly higher number of decayed surfaces (DS), decayed teeth, (DT) and missing teeth (MT) but a statistically significantly lower number of filled surfaces (FS), filled teeth (FT), functional surfaces (FSS), and functional teeth (FST). There were no differences in DMFS and DMFT between the groups of high and low dental fear. Since one of the superior aims of the dental profession is to help a patient to achieve a high number of functional teeth throughout life, consequently detecting and treating dental fear should therefore be an important aspect of dental processionals' work.
Validity of two oral health‐related quality of life measures
Authors: Robinson Peter G. , Gibson Barry , Khan Farrah A. , Birnbaum Warren
Published: December 2004

Abstract –

Objectives: To assess the validity of the Oral Impacts on Daily Performance (OIDP) and the short form of the Oral Health Impact Profile (OHIP 14) in the UK.

Setting: Primary care department at a UK dental hospital.

Sample: Consecutive patients.

Method: Cross‐sectional comparison of impacts using OIDP and OHIP 14 against clinical findings, Global Oral Health Ratings and pain.

Results: A total of 179 patients participated (83.2% response rate). OIDP had weak face validity because it contained contingency questions. Both instruments were developed from the same theoretical model and appeared to have reasonable content validity. In regression analyses, the number of impacts detected by each measure and the total score using OHIP 14 were related to the presence of oral disease and inversely related to age. No suitable transformation could be found to allow regression analysis of OIDP total scores. OHIP 14 correlated more closely with Global Oral Health Ratings but both measures correlated similarly to the experience of pain (0.43 < r < 0.47). The correlation between OHIP and OIDP scores was +0.78. The use of a simple additive method for calculating the total OHIP 14 score did not compromise its validity.

Conclusion: Both instruments have some validity as measures of Oral Health‐Related Quality of Life (OHRQoL) among dental hospital patients. The superior face, criterion and convergent validity and greater amenability to analysis of OHIP 14 render it more suitable for questionnaire‐based research and for comparing groups. The additive method may be used to calculate the total score for OHIP 14.
Profile of irritant patch testing with detergents: sodium lauryl sulfate, sodium laureth sulfate and alkyl polyglucoside
Authors: Löffler H. , Happle R.
Published: December 2004

The cutaneous reaction to detergents follows distinct kinetic rules: the duration of application and the irritant concentration are of major importance. The aim of this study was to evaluate the differences in kinetics of skin reaction between the standard irritant sodium lauryl sulfate (SLS), and 2 modern detergents: sodium laureth sulfate (SLES) and alkyl polyglucoside (APG). We performed patch testing with SLS and SLES (or APG) at different concentrations (0.125, 0.25, 0.5, 1.0 and 2.0%) and with different exposure times (6, 12 and 24 h). Evaluation was conducted by measurement of transepidermal water loss (TEWL) and laser Doppler flowmetry (LD) 24 h, 7 and 10 days after patch removal. We found a pronounced reaction to SLS, and a far milder one to SLES. Even at the highest concentration the skin reaction to APG was hard to detect. During the regeneration period (day 3–10) SLS showed even at day 10 an increased TEWL at all concentrations tested. The irritation due to SLES was convincingly detectable only up to day 7, whereas the APG‐tested skin areas showed no significant reaction even at day 3. These results demonstrate the improvement in reduction of skin irritation achieved by development of novel detergents.
Is PPD a useful screening agent?
Authors: Koopmans A. K. , Bruynzeel D. P.
Published: December 2004

In this study, the usefulness was assessed of para‐phenylenediamine (PPD) base as a marker for contact allergy to para‐compounds and disperse dyes. 59 patients with a positive reaction to PPD were patch tested with a series of para compounds and disperse dyes. This dyes series was also tested in patients with a suspect medical history of contact allergy to hair, fabric or leather dyes. In total 610 patients were tested. As 24 patients became positive over the weekend, late readings, day 6 or 7, are important. These reactions were most probably relevant in 17/24 patients. Positive reactions to PPD correlated well with reactions to para compounds like p‐aminoazobenzene and p‐toluenediamine sulphate but not with disperse dyes. Reactions to Disperse Blue (106, 124) and Orange (1 and 3) were seen most frequently. PPD is a good screening agent for hair dye, but not for disperse dye, sensitivity.
Epithelioid sarcoma: an immunohistochemical analysis evaluating the utility of cytokeratin 5/6 in distinguishing superficial epithelioid sarcoma from spindled squamous cell carcinoma
Authors: Lin Lin , Skacel Marek , Sigel Jessica E. , Bergfeld Wilma F. , Montgomery Elizabeth , Fisher Cyril , Goldblum John R.
Published: December 2004

Background:  Epithelioid sarcoma (ES) is a rare, aggressive soft tissue tumor characterized by nodular aggregates of epithelioid and/or spindled cells that are immunoreactive to cytokeratins (CKs) and epithelial membrane antigen. ES that arises in the dermis may cause epidermal ulceration and can resemble, clinically, morphologically and immunohistochemically, cutaneous squamous cell carcinoma. CK 5/6 has recently been found to be an excellent marker of squamous cell carcinoma, including spindled variants, but it is not known if this marker can be utilized to distinguish superficial ES from cutaneous spindled squamous cell carcinoma (SSCC).

Methods:  Twenty‐four cases of ES with typical histologic features and 10 cases of SSCC with ultrastructural evidence of epithelial differentiation were studied. Immunohistochemical analysis using an antibody to CK 5/6 was performed. The extent of immunoreactivity was evaluated in a semiquantitative manner using the following scale: 0, < 5% of cells staining; 1+, 6–25% of cells staining; 2+, 26–50% of cells staining; 3+, 51–75% of cells staining; 4+, > 75% of cells staining.

Results:  CK 5/6 was expressed in all 10 cases of SSCC, including one case with 3+ staining and six cases with 4+ staining. In contrast, CK 5/6 staining was found only in rare tumor cells (1+ staining) in one of 24 (4%) cases of ES.

Conclusions:  CK 5/6 staining is useful in distinguishing superficial ES from cutaneous SSCC.
Pyoderma gangrenosum: a review
Authors: Neil Crowson A. , C. Mihm Jr Martin , Magro Cynthia
Published: December 2004

Since its first description in 1930, the pathogenesis of pyoderma gangrenosum (PG) has remained obscure even as an ever‐widening array of systemic diseases has been described in association with it. The histopathologic distinction of PG from other ulcerative processes with dermal neutrophilia is challenging and at times impossible. In consequence, when confronted with a biopsy from such a lesion, the pathologist has an obligation to obtain a full and detailed clinical history. In short, as a diagnosis of PG does not hinge exclusively upon the biopsy findings in isolation from other studies, a solid knowledge of the clinical features, the systemic disease associations and the differential diagnosis will help the pathologist to avoid diagnostic pitfalls or the generation of a report which is non‐contributory to patient care. In this review, we describe in detail the different clinicopathologic forms of PG, summarize the diseases associated with this process in the literature and in our experience, and briefly review the treatment options.
Bednár tumor associated with dermal melanocytosis: melanocytic colonization or neuroectodermal multidirectional differentiation?
Authors: Goncharuk Viktor , Mulvaney Michael , Carlson J. Andrew
Published: December 2004

Background: Neuroectodermal differentiation or melanocytic colonization are the opposing theories of histogenesis for the Bednár tumor or pigmented dermatofibrosarcoma protuberans (DFSP).

Observation: A 31‐year‐old African‐American woman presented with a 2‐cm blue‐black shoulder nodule of 1‐year duration. Punch biopsy revealed a CD34+, Factor XIIIa‐DFSP, harboring numerous, pigmented spindle S100+, Mart‐1+ and HMB‐45+ cells. Subsequent wide excision demonstrated pigmented dendritic and spindled cells widely scattered throughout the dermis of the 3‐cm excisional margins and punch biopsy specimens of normal skin from both shoulders. This latter process was interpreted as dermal melanocytosis (nevus of Ito). The dermal pigmented spindle cells were Mart‐1+ and CD34−, and were associated with non‐pigmented CD34+, cytologically banal spindle cells, which were more numerous in the excisional margins than the contralateral shoulder.

Conclusion: Reported herein is a singular case of Bednár tumor associated with dermal melanocytosis. Although the coexistence of these processes implicates colonization of the DFSP by constituent dermal melanocytes, the mixed immunophenotype (CD34+ or Mart‐1+ cells) of dispersed dermal spindle cells hints at the possibility of a common cell of origin: the putative neuromesenchymal cell. In effect, the Bednár tumor could represent one part of a spectrum of neural crest‐derived dermal tumors that includes dermal melanocytosis, cellular blue nevus and conventional DFSP.