bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermospheric resistance to “greenhouse cooling”: Effect of the collisional excitation rate by atomic oxygen on the thermal response to CO2 forcing
Authors: Akmaev R. A.
Published: July 2003

Infrared radiation in the 15‐μm band of carbon dioxide is the major cooling mechanism of the middle and upper atmosphere. Increasing amounts of atmospheric CO2 impose anthropogenic influence (“greenhouse cooling”) all the way through the mesosphere and thermosphere. Collisions with atomic oxygen are the primary excitation mechanism of CO2 molecules in the thermosphere. Negative radiative forcing due to the CO2 increase is roughly proportional to the rate of collisional excitation which in turn is proportional to the rate constant of collisional deactivation. The rate constant is still somewhat uncertain at present with various measurements and estimates varying within about a factor of 4. In light of recent laboratory measurements, two sets of numerical simulations have been performed to estimate the thermospheric response to doubling and a 15% increase of CO2 for two values of the rate constant that differ by a factor of 2. Surprisingly, the temperature and density changes due to the CO2 increases are practically independent of the rate constant. Simple diagnostics show that two physical mechanisms are primarily responsible: the strong temperature dependence of the radiative forcing itself in a combination with a temperature dependence of molecular heat conduction. Since the scenarios considered for the higher rate constant generally correspond to colder temperatures, the two physical mechanisms combined provide sufficiently strong negative feedbacks to entirely offset the initially stronger radiative forcing.
Some considerations on the infrared cloud forcing
Authors: Rizzi Rolando , Maestri Tiziano
Published: July 2003

Long‐wave spectral cloud forcing is computed for realistic clouds of various optical thickness embedded in the tropical and subarctic winter standard atmospheres. The strict connections between the integrated long‐wave cloud forcing (LCF) and cloud's altitude and transmissivity are shown. LCF, especially in presence of ice clouds, grows almost linearly with cloud transmissivity, and largest values are found in presence of high and opaque cirri. We have also considered the effect of incomplete spectral coverage in broadband long‐wave radiometry when estimating LCF. The error has been computed as a function of edge cutoff (two different filters are used) and cloud's transmissivity and top altitude. Uncorrected measurements from sensors with incomplete spectral coverage generally underestimate the real LCF, especially for the highest cirrus clouds in the tropics. A correction is possible since the percentage error is practically constant with cloud's transmissivity.
Early manifestations of testicular dysgenesis in children: pathological phenotypes, karyotype correlations and precursor stages of tumour development
Authors: CHEMES HÉCTOR E. , MUZULIN PATRICIA M. , VENARA MARCELA C. , DEL CARMEN MUHLMANN MARÍA , MARTÍNEZ MACARENA , GAMBONI MERCEDES
Published: July 2003

Testicular dysgenesis derives from abnormal gonadal development caused by chromosome aberrations/mosaicisms or mutations/deletions in SRY or other genes responsible for testicular differentiation. Dysgenetic male pseudohaermaphroditism has bilateral dysgenetic testes characterized by a cortical network of anastomosing seminiferous cords that penetrate a thin albuginea. In asymmetric gonadal differentiation (or Mixed Gonadal Dysgenesis) a dysgenetic testis associates with a streak gonad with primitive sex cords embedded in an ovarian‐like stroma. Uni‐ or bilateral ovotestes identify true haermaphroditism. Fluorescent in situ hybridisation studies demonstrate that the sex chromosomes of mosaic patients do not distribute homogeneously in asymmetric gonads. 45,X lines predominate over 46,XY in streak gonads, while the relationship between these two is more equivalent in dysgenetic testes, suggesting that testicular or streak differentiation is related to the balance between X0 and XY lines. Testicular dysgenesis is more severe when there is a frank predominance of X0 or XX cells. Higher percentages of XY cells coincide with lesser degrees of dysgenesis. DNA densitometry indicate a higher incidence of neoplastic transformation than previously anticipated. Various specimens showed clear aneuploid histograms but no clear indication of a cytological CIS phenotype. There was a wide cytological variation in aneuploid germ cells, ranging from normally looking big infantile spermatogonia to gonocyte/CIS cells. Aneuploidy probably precedes the full expression of the CIS phenotype. In case of doubt we recommend DNA densitometry to either confirm or discard their neoplastic nature. The earliest recognizable change in germ cell tumorigenesis is probably the polyploidisation of fetal germ cells, followed by the expression of the CIS phenotype in isolated germ cells scattered along infantile seminiferous tubules that later proliferate to give an adult type CIS pattern.
Genetic engineering to study testicular tumorigenesis
Authors: YAN WEI , BURNS KATHLEEN H. , MATZUK MARTIN M.
Published: July 2003

In humans, Sertoli cell tumors account for approximately 4% of all testicular tumors, and 20% of these are malignant. The mechanisms underlying Sertoli cell tumorigenesis remain largely unknown. Using gene knockout technology, we previously generated mutant mice lacking the α subunit of inhibin dimers. The inhibin α‐null male mice develop testicular Sertoli cell tumors with 100% penetrance. These tumors develop as early as 4 weeks of age and cause a cachexia‐like wasting syndrome. Castrated inhibin α knockout mice develop sex steroidogenic adrenal cortical tumors. These studies have identified inhibins as secreted tumor suppressors with specificity for the gonads and adrenal glands. It had been suggested that endocrine factors play roles in Sertoli cell tumorigenesis by altering cell cycle machinery of the Sertoli cells. To test the potential of these factors to function as modifiers of Sertoli cell tumorigenesis, we have employed a genetic intercross strategy, breeding inhibin α mutant mice with mutant mice deficient in endocrine signaling factors including gonadotropin releasing hormone (hypogonadal, hpg mice), follicle stimulating hormone, anti‐Müllerian hormone (MH), activin receptor type II, or androgen receptor (testicular feminization, tfm mice), or mice overexpressing follistatin. We are also investigating the effects of loss of critical cell cycle regulators, such as cyclin dependent kinase inhibitor p27, on Sertoli cell tumorigenesis in inhibin α knockout males. These studies clearly demonstrate the roles of these factors as modifiers of the Sertoli cell tumorigenesis. Activin signaling through activin receptor type II is responsible for the cachexia‐like syndrome observed in the inhibin α knockout mice with tumors. The gonadotropin hormones are essential for testicular tumor development, but elevated FSH levels are not sufficient to cause Sertoli cell tumors. Absence of FSH, lack of androgen receptor, or overexpression of follistatin slows the tumor growth and minimizes the cachexia symptoms, thus prolonging the life span of these double mutant mice. In contrast, absence of AMH or p27 causes earlier onset and more aggressive development of testicular tumor, with an earlier death of double mutant mice. We are currently investigating roles of estrogen signaling pathways, and other cell cycle regulators, in tumor development in the inhibin α knockout mice by generating mice with double or triple mutations. Genetic engineering in mouse models provides a powerful tool to study the mechanisms of testicular tumorigenesis and define the important genetic modifiers in vivo.
Expression of Wnt and Notch pathway genes in a pluripotent human embryonal carcinoma cell line and embryonic stem cells
Authors: WALSH JAMES , ANDREWS PETER W.
Published: July 2003

Embryonal carcinoma (C) cells, the pluripotent stem cells of teratocarcinomas, show many similarities to embryonic stem (S) cells. Since EC cells are malignant but their terminally differentiated derivatives are not, understanding the molecular mechanisms that regulate their differentiation may be of value for diagnostic and therapeutic purposes. We have examined the expression of multiple components of two developmentally important cell‐cell signalling pathways, Wnt and Notch, in the pluripotent human EC cell line, NTERA2, and the human ES cell line, H7. Both pathways have well‐documented roles in controlling neurogenesis, a process that occurs largely in response to retinoic acid (A) treatment of NTERA2 cultures and spontaneously in H7 cultures. In NTERA2, many of the genes tested showed altered transcriptional regulation following treatment with RA. These include members of the frizzled gene family (FZD1, FZD3, FZD4, FZD5, FZD6), encoding receptors for Wnt proteins, the FrizzledRelated Protein family (SFRP1, SFRP2, FRZB, SFRP4), encoding soluble Wnt antagonists and also ligands and receptors of the Notch pathway (Dlk1, Jagged1; Notch1, Notch2, Notch3). Few differences were found in the repertoire of Wnt and Notch pathway genes expressed by NTERA2 EC cells and H7 ES cells. We present a model in which interactions between and regulation of Wnt and Notch signalling are important in maintaining EC/ES stem cells and also controlling their differentiation.
Deregulation of the G1/S‐phase control in human testicular germ cell tumours
Authors: BARTKOVA JIRINA , RAJPERT‐DE MEYTS EWA , SKAKKEBÆK NIELS E. , LUKAS JIRI , BARTEK JIRI
Published: July 2003

Deregulated cell cycle and defective genome‐integrity checkpoints are among the hallmarks of cancer. Here we summarize our recent studies of key components of the G1/S machinery in normal human spermatogenesis, and their abnormalities in testicular germ cell tumours (TGCTs), with special emphasis on carcinoma in situ lesions (CIS). Our combined immunohistochemical and immunoblotting analyses of normal human adult and fetal testes, CIS, seminomas, embryonal carcinomas, and teratomas, revealed an ‘unorthodox’ spectrum of defects within the so‐called RB pathway in TGCTs. The early aberrations included lack of expression of the retinoblastoma tumour suppressor (pRB) and the CDK inhibitor p19ink4d, and overexpression of cyclin D2. Progression from CIS to invasive TGCTs was associated with loss of another two CDK inhibitors and tumour suppressors: p16ink4a and p18ink4c. We also found the lack of pRB and p19ink4d in fetal gonocytes, the candidate target cell for all types of TGCTs. These findings, together with the status of the Chk2–p53 DNA‐integrity checkpoint, are considered in relation to the origin, biology and pathogenesis of TGCTs, and potential implications of the G1/S defects for the curability of these tumours.
Influence of sex hormones on the periodontium
Authors: Mascarenhas Paulo , Gapski Ricardo , Al‐Shammari Khalaf , Wang Hom‐Lay
Published: July 2003

Objectives: Sex hormones have long been considered to play an influential role on periodontal tissues, bone turnover rate, wound healing and periodontal disease progression. The objectives of this review article are to (1) address the link between sex hormones and the periodontium, (2) analyse how these hormones influence the periodontium at different life times and (3) discuss the effects of hormone supplements/replacement on the periodontium.

Materials and Methods: Two autonomous searches were performed in English language utilizing Medline, Premedline and Pubmed as the online databases. Publications up to 2002 were selected and further reviewed. In addition, a manual search was also performed including specific related journals and books.

Results: It is certain that sexual hormones play a key role in periodontal disease progression and wound healing. More specifically, these effects seem to differentiate by gender as well as lifetime period. In addition, the influence of sex hormones can be minimized with good plaque control and with hormone replacement.

Conclusion: Despite profound research linking periodontal condition with sex hormones kinetics, more definitive molecular mechanisms and therapy still remain to be determined.
Association between level of education and oral health status in 35‐, 50‐, 65‐ and 75‐year‐olds
Authors: Paulander J. , Axelsson P. , Lindhe J.
Published: July 2003

Aim: The aim of the present study was to evaluate the association between educational level and dental disease, treatment needs and oral hygiene habits.

Material and methods: Randomized samples of 35‐, 50‐, 65‐ and 75‐year‐olds, classified according to the educational level: [low (LE): elementary school or higher (HE)], were identified. In 1091 subjects, a number of characteristics such as (i) number of teeth, (ii) periodontal attachment levels (PAL), (iii) caries and (iv) occlusal function were recorded. Educational level, oral hygiene and dietary habits were self‐reported. Non‐parametric variables were analyzed by χ2, Mann–Whitney U–Wilcoxon's rank sum tests, and parametric variables by Student's t‐test (level of significance 95%). A two‐way anova was performed on decayed, missing and filled surfaces to investigate the interaction between age and educational level. All statistical procedures were performed in the SPSS© statistical package.

Results: The number of remaining teeth was similar for LE and HE in the 35‐year olds (25.8 versus 26.6), but in the older age groups LE had significantly a larger number of missing teeth. The LE groups (except in 65‐year olds) exhibited significantly more PAL loss. LE had significantly fewer healthy gingival units in all but the 75‐year age group. In all age groups, LE had fewer intact tooth surfaces and a significantly poorer occlusal function. The frequency of tooth cleaning measures and dietary habits did not differ between LE and HE.

Conclusion: Educational level was shown to influence the oral conditions and should be considered in assessing risk, and in planning appropriate preventive measures.
Ultrastructure of the gingiva in cardiac patients treated with or without calcium channel blockers
Authors: Bullon P. , Pugnaloni A. , Gallardo I. , Machuca G. , Hevia A. , Battino M.
Published: July 2003

Objectives: In the last few years, several studies have suggested that periodontal diseases are related to the development of atherosclerosis and its complications. Our objective was to study the ultrastructural morphology of the gingiva from cardiac patients, some of whom were treated and some not with calcium channel blockers compared to a control group.

Material and Methods: Fifty‐five patients were studied and grouped in the following way: (a) healthy group (HG) (n=12) healthy patients with at least two pockets between 3 and 5 mm; (b) cardiac group (CG) (n=12) patients with cardiac disease untreated with calcium channel blockers; (c) diltiazem group (DG) (n=13) cardiac patients treated with diltiazem; (d) nifedipine group (NG) (n=18) cardiac patients treated with nifedipine.

Results: Ultrastructural studies in the CG showed inflammatory cells, collagen fibers disruption and a more extended morphologically compromised fibroblast mitochondria. Morphometric studies in CG showed mitochondria that were impaired in number but increased in volume, suggesting metabolic cell suffering. In DG and NG, morphometric data were similar to HG. The presence of myofibroblasts and collagen neosynthesis was detected in DG and NG.

Conclusions: Our data showed differences in the ultrastructure of the gingival fibroblasts between the studied groups; the DG and NG showed features that could be interpreted as an attempt to restore the cellular metabolic function.
Long‐term effect of full‐mouth tooth extraction on the responsiveness of peripheral blood monocytes
Authors: Fokkema Schelte J. , Loos Bruno G. , Hart Augustinus A.M. , Van Der Velden Ubele
Published: July 2003

Background: As some residual inflammation may remain after periodontal therapy, the present pilot study investigated the long‐term effect of full‐mouth tooth extraction therapy on the responsiveness of peripheral blood monocytes in a case with generalized terminal adult periodontitis.

Methods: Before and 3, 9, 20 and 32 months after therapy, venous blood was collected. Total and differential white blood cell counts were determined and whole blood cell cultures (WBCC) were incubated with lipopolysaccharide (LPS) to stimulate the production of inflammatory mediators by monocytes.

Results: After full‐mouth tooth extraction, the numbers of total peripheral white blood cells and neutrophils decreased over time. The release of the chemokines interleukin (IL)‐8 and macrophage chemoattractant protein (MCP)‐1 in the cultures decreased twofold over time, whereas no changes were seen for the other studied cytokines, chemokines and prostaglandin E2.

Conclusion: On the basis of previous studies and the present case, the high production of IL‐8 and MCP‐1 by monocytes in LPS‐stimulated WBCC from periodontitis patients is most likely acquired, as their levels decrease over time when the periodontal infection is controlled. The possible connection between periodontitis and atherosclerosis through IL‐8 and MCP‐1 is discussed.
Periodontitis and perceived risk for periodontitis in elders with evidence of depression
Authors: Persson G. R. , Persson R. E. , MacEntee C. I. , Wyatt C. C. I. I. , Hollender L. G. , Kiyak H. A.
Published: July 2003

Background: Depression and periodontitis are common conditions in older adults. There is some evidence that these two conditions may be related.

Aims: To study a population of dentate elders and assess the prevalence of depression, self‐assessment of risk for periodontitis and tooth loss, in relation to periodontal disease status.

Material and methods: Data were obtained from 701 older subjects (mean age 67.2 years (SD±4.6), of whom 59.5% were women. Self‐reports of a diagnosis of depression, scores of the Geriatric Depression Scale (GDS), and self‐assessment of risk for future tooth loss and periodontitis were compared with a diagnosis of periodontitis based on probing depth, and bone loss assessed from panoramic radiographs. Other systemic diseases and smoking habits were also determined and studied in relation to depression.

Results: A history of depression was reported by 20% of the subjects. GDS scores 8 were reported by 9.8% of the elders. Periodontitis was identified in 48.5% of the subjects. Depression was associated with heart attack (p<0.05), stroke (p<0.01), high blood pressure (p<0.02), all combined cardiovascular diseases (p<0.001), chronic pain (p<0.01), osteoarthritis (p<0.001), and osteoporosis (p< 0.001) but not with periodontitis (p=0.73). Subjects with depression had a higher self‐reported risk score for future tooth loss (p<0.02). No group difference emerged for self‐perceived risk for periodontitis. Logistic regression analysis demonstrated that a past history of tooth loss (p<0.001), self‐perceived risk for periodontitis (p<0.02), the number of years with a smoking habit (p<0.02), and male gender (p<0.02) were associated with a diagnosis of periodontitis but neither measure of depression could be included in an explanatory model for periodontitis.

Conclusions: Evidence of depression (self‐report or by GDS) is not associated with risk for periodontitis in older subjects but is associated with tooth loss and chronic conditions associated with pain.
Efficacy of plaque removal and learning effect of a powered and a manual toothbrush
Authors: Lazarescu D. , Boccaneala S. , Illiescu A. , De Boever J. A.
Published: July 2003

Background: Subjects with high plaque and gingivitis scores can profit most from the introduction of new manual or powered tooth brushes. To improve their hygiene, not only the technical characteristics of new brushes but also the learning effect in efficient handling are of importance.

Aim: The present study compared the efficacy in plaque removal of an electric and a manual toothbrush in a general population and analysed the learning effect in efficient handling.

Method: Eighty healthy subjects, unfamiliar with electric brushes, were divided into two groups: group 1 used the Philips/Jordan HP 735 powered brush and group 2 used a manual brush, Oral‐B40+. Plaque index (PI) and gingival bleeding index (GBI) were assessed at baseline and at weeks 3, 6, 12 and 18. After each evaluation, patients abstained from oral hygiene for 24 h. The next day a 3‐min supervised brushing was perfomed. Before and after this brushing, PI was assessed for the estimation of the individual learning effect. The study was single blinded.

Results: Over the 18‐week period, PI reduced gradually and statistically significantly (p<0.001) in group 1 from 2.9 (±0.38) to 1.5 (±0.24) and in group 2 from 2.9 (±0.34) to 2.2 (±0.23). From week 3 onwards, the difference between groups was statistically significant (p<0.001). The bleeding index decreased in group 1 from 28% (±17%) to 7% (±5%) (p<0.001) and in group 2 from 30% (±12%) to 12% (±6%) (p<0.001). The difference between groups was statistically significant (p<0.001) from week 6 onwards. The learning effect, expressed as the percentage of plaque reduction after 3 min of supervised brushing, was 33% for group 1 and 26% for group 2 at week 0. This percentage increased at week 18 to 64% in group 1 and 44% in group 2 (difference between groups statistically significant: p<0.001).

Conclusion: The powered brush was significantly more efficient in removing plaque and improving gingival health than the manual brush in the group of subjects unfamiliar with electric brushes. There was also a significant learning effect that was more pronounced with the electric toothbrush.
Periodontal repair in dogs: rhBMP‐2 significantly enhances bone formation under provisions for guided tissue regeneration
Authors: Wikesjö Ulf M. E. , Xiropaidis Andreas V. , Thomson Robert C. , Cook Alonzo D. , Selvig Knut A. , Hardwick W. Ross
Published: July 2003

Background: Recombinant human bone morphogenetic protein‐2 (rhBMP‐2) has been shown to support the regeneration of alveolar bone and periodontal attachment in surgically created periodontal defects and in defects with a history of dental plaque and calculus exposure. Periodontal regeneration has also been shown following guided tissue regeneration using space‐providing expanded polytetrafluoroethylene (ePTFE) devices. The objective of this study was to evaluate the influence of rhBMP‐2 on regeneration of alveolar bone and periodontal attachment used in conjunction with a space‐providing ePTFE device.

Methods: Routine, critical‐size, 5–6 mm, supra‐alveolar, periodontal defects were created around the third and fourth mandibular premolar teeth in four young adult Hound Labrador mongrel dogs. rhBMP‐2 (0.2 mg/ml) in an absorbable collagen sponge (rhBMP‐2/ACS) or buffer/ACS (control) implants were randomly assigned to be placed around the premolar teeth in the left and right jaw quadrants in subsequent animals. Space‐providing ePTFE devices with 300‐μm laser‐drilled pores, 0.8 mm apart, were used to cover the rhBMP‐2 and control implants. The gingival flaps were advanced for primary wound closure. The animals were euthanized at 8 weeks postsurgery for histologic and histometric analyses.

Results: Bone regeneration and ankylosis were significantly increased in jaw quadrants receiving rhBMP‐2/ACS compared to control (bone height 4.8±0.3 versus 2.0±0.2 mm, p=0.001; bone area 10.9±1.3 versus 1.4±0.1 mm2; p=0.009, and ankylosis 2.2±0.2 versus 0.04±0.7 mm; p=0.01). No differences between groups were found for cementum regeneration and root resorption.

Conclusions: rhBMP‐2 significantly enhances regeneration of alveolar bone in conjunction with a space‐providing, macroporous ePTFE device for GTR.
Periodontal repair in dogs: space‐providing ePTFE devices increase rhBMP‐2/ACS‐induced bone formation
Authors: Wikesjö Ulf M.E. , Xiropaidis Andreas V. , Thomson Robert C. , Cook Alonzo D. , Selvig Knut A. , Hardwick W. Ross
Published: July 2003

Background: Recombinant human bone morphogenetic protein‐2 (rhBMP‐2) technologies have been shown to enhance alveolar bone formation significantly. Biomaterial (carrier) limitations, however, have restricted their biologic potential for indications where compressive forces may limit the volume of bone formed. The objective of this proof‐of‐principle study was to evaluate the potential of a space‐providing, macroporous ePTFE device to define rhBMP‐2‐induced alveolar bone formation using a discriminating onlay defect model.

Methods: Routine, critical size, 5–6 mm, supra‐alveolar, periodontal defects were created around the third and fourth mandibular premolar teeth in four young adult Hound Labrador mongrel dogs. All jaw quadrants received rhBMP‐2 (0.4 mg) in an absorbable collagen sponge (ACS) carrier. Contralateral jaw quadrants in subsequent animals were randomly assigned to receive additionally the dome‐shaped, macroporous ePTFE device over the rhBMP‐2/ACS implant or no additional treatment. The gingival flaps were advanced to cover the ePTFE device and teeth, and sutured. Animals were scheduled for euthanasia to provide for histologic observations of healing at 8 weeks postsurgery.

Results: Healing was uneventful without device exposures. New bone formation averaged (±SD) 4.7±0.2 mm (98%) and 4.5±0.4 mm (94%) of the defect height, respectively, for jaw quadrants receiving rhBMP‐2/ACS with the ePTFE device or rhBMP‐2/ACS alone (p>0.05). In contrast, the regenerated bone area was significantly enhanced in jaw quadrants receiving rhBMP‐2/ACS with the ePTFE device compared to rhBMP‐2/ACS alone (9.3±2.7 versus 5.1±1.1 mm2; p<0.05). Cementum formation was similar for both treatment groups. Ankylosis compromised periodontal regeneration in all sites.

Conclusions: The results suggest that the novel space‐providing, macroporous ePTFE device appears suitable as a template to define rhBMP‐2/ACS‐induced alveolar bone formation.
Effectiveness of a combination of platelet‐rich plasma, bovine porous bone mineral and guided tissue regeneration in the treatment of mandibular grade II molar furcations in humans
Authors: Lekovic Vojislav , Camargo Paulo M. , Weinlaender Michael , Vasilic Nikola , Aleksic Zoran , Kenney E. Barrie
Published: July 2003

Objective: A combination of platelet‐rich plasma (PRP), bovine porous bone mineral (BPBM) and guided tissue regeneration (GTR) has been shown to be effective as regenerative treatment for intrabony periodontal defects. The purpose of this study was to evaluate the effectiveness of PRP, BPBM and GTR used in combination as regenerative treatment for grade II molar furcation defects in humans.

Material and methods: Using a split‐mouth design, a total of 52 grade II mandibular molar furcation defects were treated either with PRP/BPBM/GTR (experimental group, n=26) or with an open flap debridement (control group, n=26). The primary outcomes evaluated in this study included changes in pocket depth, attachment level and re‐entry bone levels (horizontal and vertical) between baseline and 6 months postoperatively.

Results: The results showed that the experimental group presented with significantly greater pocket reduction (4.07±0.33 mm for experimental and 2.49±0.38 mm for control sites), gain in clinical attachment (3.29 ± 0.42 mm for experimental and 1.68±0.31 mm for control sites), vertical defect fill (2.56± 0.36 mm for experimental and −0.19±0.02 for control sites) and horizontal defect fill (2.28±0.33 mm for experimental and 0.08±0.02 mm for control sites) than the control group.

Conclusions: It was concluded that the PRP/BPBM/GTR combined technique is an effective modality of regenerative treatment for mandibular grade II furcation defects. Further studies are necessary to elucidate the role played by each component of the combined therapy in achieving these results.
Levels of aspartate aminotransferase (AST) in saliva of patients with different periodontal conditions
Authors: Cesco Ricardo de Toledo , Ito Izabel Yoko , Albuquerque Rubens Ferreira de
Published: July 2003

Objectives: The purpose of this study was to evaluate the relationship between aspartate aminotransferase (AST) levels in saliva measured by Reflotron™ System of Diagnosis and periodontal condition indicated by Community Periodontal Index of Treatment Needs (CPITN).

Material and methods: Fifteen patients were assigned to one of four groups C0, C1, C3 and C4, based on their largest CPITN code among the examined sites, totaling 60 participants. About 1.0 ml of non‐stimulated saliva was collected from the individuals after a mouth rinse with water. Biochemical analyses of saliva samples were carried out using the proposed system in order to quantify their AST concentration.

Results: There were no significant differences between levels (U/ml) of AST (median; interquartile range) from groups C0 (30.9; 14.7–41.7), C1 (30.3; 19.5–39.4) and C3 (35.1; 27.0–63.5). However, group C4 (106.2; 84.4–129.7) differed statistically from the others (p<0.001) and presented AST levels as high as 284.2 U/ml. Gingival bleeding and suppuration were observed in three individuals with concentrations higher than 125.0 U/ml.

Conclusion: Levels of AST in saliva from patients presenting CPITN code 4 were higher than from patients coded lower and could be detected by the evaluated diagnostic system. Periodontal destruction such as periodontal pockets, gingival bleeding and suppuration seems to be related to higher AST levels in saliva.
Evaluation of enamel matrix derivative as an adjunct to non‐surgical periodontal therapy
Authors: Gutierrez Mauricio A. , Mellonig James T. , Cochran David L.
Published: July 2003

Objectives: The aim of this study was to evaluate the adjunctive use of enamel matrix derivative (EMD) on periodontal healing following nonsurgical periodontal therapy (scaling and root planing – SRP).

Material and methods: The study was performed as an intraindividual, longitudinal trial of 3 months duration with a double‐blinded, split‐mouth, controlled, and randomized design. Twenty‐two patients with moderate to severe chronic periodontitis were enrolled in the study. In each patient, two sites with pocket depths 5 mm and with radiographic angular bone defects >3 mm were selected. Baseline examination included measurement of probing pocket depth (PPD) and clinical attachment levels (CAL). The presence or absence of plaque and bleeding on probing at selected sites was also recorded. Following initial examination, full‐mouth SRP was performed. Study sites were then treated with 24% EDTA for 2 min, followed by thorough irrigation with sterile saline. The sites were then randomized. The experimental site received subgingival application of enamel matrix derivative (Emdogain®, BIORA AB, Malmo, Sweden). The control site received no additional treatment. At 3 months, all sites were re‐examined. The response to therapy in experimental and control sites was evaluated, using change in probing depth and CAL as the primary outcome variables. Statistical analysis (paired t‐tests) was used to compare response to treatment in control versus experimental sites.

Results: Statistically significant changes in PPD and CAL were seen in both treatment groups from baseline to 3 months. The mean PPD reduction was 2.3±0.5 mm for control sites and 2.0±0.3 mm for experimental sites. The mean CAL gain was 1.8±0.4 mm for control sites, and 1.4±0.3 mm for experimental sites. Statistical analysis, however, revealed no significant difference in PPD reduction or CAL gain between experimental and control groups (p>0.4). In addition, no difference was found between treatment groups in bleeding or plaque indices at 3 months.

Conclusion: The findings from the present study do not support the use of EMD during routine, nonsurgical debridement of periodontal pockets as measured 3 months post SRP.
Enamel matrix derivative exhibits angiogenic effect in vitro and in a murine model
Authors: Yuan Kuo , Chen Chun‐Liang , Lin Ming T.
Published: July 2003

Objectives: Angiogenesis is one of the most critical events in the wound healing process. Any increase in angiogenesis could result in more rapid and complete healing. A recent study found that enamel matrix derivative (EMD) could accelerate early periodontal wound healing. We wanted to clarify whether EMD caused an angiogenic effect and, thus, possibly enhanced wound healing.

Methods: We performed in vitro proliferation and chemotaxis assays on human umbilical vein endothelial cell (HUVEC) cultures, and a tissue culture assay using blood vessel fragments in fibrin gel. Collagen membranes soaked with EMD were implanted subcutaneously in mice to test the in vivo angiogenic effect.

Results: While there were no significant differences between the negative control and EMD groups in the proliferation assay, EMD treatment did exhibit a significantly greater dose‐dependent chemotactic effect on HUVEC than control group treatments. The tissue culture in fibrin gel showed new blood vessel outgrowths in the EMD groups, but none in the negative control group. In the animal studies, significantly more endothelial cells were detected in the EMD group of mice.

Conclusions: Our findings show that EMD does exhibit some angiogenic effects. However, the underlying molecules and mechanisms are still unidentified. We discuss several possibilities.
The permeability of oral leukoplakia
Authors: Bánóczy Jolán , Squier Christopher A. , Kremer Mary , Wertz Philip W. , Kövesi György , Szende Béla , Dombi Csaba
Published: July 2003

The significant increase in oral cancer mortality necessitates further research on the mechanisms of tumorigenesis. It was the aim of this study to compare the permeability, lipid composition and histopathological characteristics of oral leukoplakia with non‐lesional specimens of the same region in 30 cases as well as 11 specimens originating from healthy control buccal mucosa. The permeability (Kp) of tissue biopsies to tritiated nitrosonornicotine was determined in a continuous through‐flow perfusion system, lipids were extracted and identified by thin‐layer chromatography, and thickness of epithelium and keratin layer assessed by histopathological methods. Results of the measurements showed that the permeability to the tobacco carcinogen, nitrosonornicotine for leukoplakic tissue was higher than for normal control buccal specimens. Non‐lesional areas of buccal mucosa, adjacent to leukoplakias, showed hyperplasia and significantly higher permeability values than both leukoplakic and normal buccal control mucosa. The lipid content of the non‐lesional sites was intermediate between the increased values of the leukoplakic lesion and of normal control mucosa. The data strongly suggest that the presence of tobacco in the oral cavity may bring about generalized changes even in regions that do not show leukoplakia.
Burning mouth syndrome: experiences from the perspective of female patients
Authors: Hakeberg Magnus , Hallberg Lillemor R‐M. , Berggren Ulf
Published: July 2003

The aim of this study was to gain a deeper understanding of the development of burning mouth syndrome (BMS). Eighteen females (43–80 yr old), referred to the Clinic of Oral Medicine, formed the study group. Oral examination did not reveal any mucosal lesion or dental pathology, blood analyses of vitamin B12and serum iron levels were within normal reference values, and no allergies to dental materials were reported. Reported pain/discomfort was 49.4 (mean) on a 100‐mm visual analog scale and duration of symptoms was, on average, 8.1 yr (median = 1.5 yr). Taped semistructured interviews were transcribed and analysed in line with grounded theory methodology. In the analysis, a core category emerged, labeledcommunicating psychological discomfort.This category indicated musings about the meaning of life and interacted with a personality characterized by astrong need for conscientiousness,a life style including long‐standingstruggle with psychosocial overload, andexternalsocial and cultural influences.The debut of the BMS was then preceded by anacutely stressful event. A psychosocial history, in addition to a detailed dental and medical history, seems to be crucial in diagnosing patients. If a psychological disorder and somatization of anxiety and depression is suggested, as indicated in our study, the patient should be offered counseling by a psychologist.
Exclusion of candidate genes in two families with autosomal dominant hypocalcified amelogenesis imperfecta
Authors: Hart P. Suzanne , Wright J. Timothy , Savage Mathew , Kang George , Bensen Jeannette T. , Gorry Michael C. , Hart Thomas C.
Published: July 2003

The amelogenesis imperfectas (AI) are a group of hereditary enamel defects characterized by clinical and genetic diversity. The most common AI types are inherited as autosomal traits. Three mutations of the enamelin (ENAM) gene have been found in cases of autosomal dominant hypoplastic AI. The gene(s) responsible for hypocalcified forms of AI have not been identified, although a number of autosomal genes have been proposed as candidates for AI based on their expression by ameloblasts, including ameloblastin and enamelin (chromosome 4q13.3), tuftelin (chromosome 1q21), enamelysin (chromosome 11q22.3‐q23) and kallikrein 4 (chromosome 19q13.3‐q13.4). To localize the gene(s) responsible for autosomal dominant hypocalcified AI, we evaluated support for/against linkage of AI to genetic markers spanning five AI candidate genes in two extended families. Our data excluded all proposed candidate gene regions as causal for autosomal dominant hypocalcified AI in these families. These linkage findings provide further evidence for genetic heterogeneity among families with autosomal dominant AI and indicate that, at least, some forms of autosomal dominant hypocalcified AI are not caused by a gene in the five most commonly reported AI candidate genes.
Pulp cell responses during hypoxia and reoxygenation in vitro
Authors: Amemiya Kei , Kaneko Yuzuru , Muramatsu Takashi , Shimono Masaki , Inoue Takashi
Published: July 2003

The purpose of this study was to investigate pulp cell responses during hypoxia and reoxygenation. Pulp tissues obtained from beagle dogs were cultured. In the control group, pulp cells were incubated in normoxic conditions (20% O2) for 1–4 d. In the hypoxia group, pulp cells were incubated under hypoxic conditions (2% O2) for 1–4 d. In the reoxygenation group, pulp cells were first incubated under hypoxic conditions for 24 h, and were then incubated in normoxic conditions (20% O2) for one to three additional days. Cell viability, MTT (3‐ (4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) reduction assay, cellular proliferation, and alkaline phosphatase (ALPase) activity were determined. Expression of heat shock protein 70 (HSP70) and vascular endothelial growth factor (VEGF) was analysed by Western blotting. Hypoxia inducible factor‐1α (HIF‐1α) in pulp cells was analysed by reverse transcriptase polymerase chain reaction (RT‐PCR). The cell growth rate and ALPase activity were significantly higher in the hypoxia group than in the control group. After reoxygenation, cellular proliferation and ALPase activity decreased to the level of the control group while HSP70 expression increased. Hypoxia inducible factor‐1α expression was detected in pulp cells, and VEGF expression (which is regulated by HIF‐1α) increased under hypoxic conditions. These results suggest that dynamic responses to hypoxia and reoxygenation occur in pulp cells.
Surface characteristics of dentin experimentally exposed to hydrofluoric acid
Authors: Pioch Thomas , Jakob Heiko , García‐Godoy Franklin , Götz Hermann , Dörfer Christof E. , Staehle Hans J.
Published: July 2003

The purpose of this study was to test the effect of hydrofluoric acid (HF) on the surface characteristics of dentin in vitro. Dentin was exposed in 50 human molars and divided into five groups according to different etching schedules: (i) no etching, (ii) 15 s HF, (iii) 15 s H3PO4, (iv) 15 s HF and 15 s H3PO4, (v) 15 s H3PO4 and 15 s HF. Teeth were examined under a scanning electron microscope equipped with energy‐dispersive X‐ray (EDX) or two layers of fluorescence‐labeled primer followed by the composite were applied, and the teeth were sectioned and examined using confocal laser scanning microscopy (CLSM). With scanning electron microscopy, no openings of dentinal tubules were found in groups (i), (ii), and (iv). In group (v) only a few tubules were opened and in group (iii) the smear layer was completely removed and tubules appeared open. The EDX analysis revealed that fluoride was incorporated into the dentin surface when HF was used. With CLSM, distinct hybrid layers could be detected only in group (iii). In group (v) the hybrid layer appeared less established compared with group (iii). No dentin hybridization was found in groups (i), (ii), and (iv). It is concluded that HF has the ability to close the openings of dentin tubules which were opened due to etching by phosphoric acid and cannot dissolve the smear layer.
Impulsive compression influences the viscous behavior of porcine temporomandibular joint disc
Authors: Tanaka Eiji , Kawai Nobuhiko , Van Eijden Theo , Watanabe Mineo , Hanaoka Koichi , Nishi Mika , Iwabe Tatsunori , Tanne Kazuo
Published: July 2003

Traumatic joint injury is known to produce osteoarthritic degeneration in the temporomandibular joint (TMJ). However, little information, is available on its possible effect on the dynamic viscoelastic behavior of the disc. In the present study, impulsive compression was applied to the disc as a model for traumatic joint injury. This was tested in 32 porcine discs. Prior to a dynamic tensile test, impulsive compression with strain rates of 0.01, 0.1 and 1 s−1 to a final strain of 30% was applied to these discs. Tensile stress was applied in the antero‐posterior direction with a wide range of frequencies (0.1–100 Hz). The dynamic E‐moduli increased as the loading frequency increased. The dynamic viscosity and elasticity decreased with an increase of strain rate, although the effect on viscosity was greater than on elasticity. The results suggest that strain rate and subsequent peak stress of impulsive compression affect primarily the dynamic viscosity of the disc, and that impulsive compression at high strain rates reduces the resistance of the TMJ disc to stress, resulting in permanent disc deformation and perforation.
Effects of local injection of prilocaine–felypressin on the myocardial oxygen balance in dogs
Authors: Miyachi Kenji , Ichinohe Tatsuya , Kaneko Yuzuru
Published: July 2003

The authors investigated the effects of felypressin (Fely), a non‐adrenergic vasoconstrictor, used together with prilocaine on myocardial oxygen balance. Six open‐chest dogs were studied under urethane and α‐chloralose anesthesia. Systolic arterial pressure, diastolic arterial pressure, mean pulmonary arterial pressure and pulmonary capillary wedge pressure, heart rate, coronary blood flow (CBF), internal and external myocardial oxygen tension (int‐ or ext‐PmO2), and cardiac output were observed. Three doses of Citanest–Octapressin, which contains 3% prilocaine and 0.03 IU ml−1 Fely (Pri‐Fely) – 0.09, 0.18, and 0.3 ml kg−1– were injected into the tongue. Observations were performed up to 60 min after the injection. The CBF and int‐PmO2 was reduced following the injection of each of the three doses of Pri‐Fely. There were negative correlations between the Pri‐Fely dose per body weight and the maximum reductions in CBF (r = 0.52, P > 0.05), in int‐PmO2 (r = 0.78, P > 0.05), and in ext‐PmO2 (r = 0.55, P > 0.05), respectively. These results suggest that an administration of Fely at doses more than 2.7–5.4 mIU kg−1 (3–6 cartridges of Pri‐Fely) may induce an imbalance between the oxygen supply and demand in myocardial tissues of patients with cardiovascular diseases.
Expression and role of RANKL in periodontal ligament cells during physiological root‐resorption in human deciduous teeth
Authors: Fukushima Hidefumi , Kajiya Hiroshi , Takada Keisuke , Okamoto Fujio , Okabe Koji
Published: July 2003

Although important roles of receptor activator of NF‐κB ligand (RANKL) and its receptor (RANK) have been established for osteoclastogenesis and bone resorption, their expression and roles during physiological root resorption remain uncertain. Physiological root resorption for shedding of human deciduous teeth is mediated by osteoclast‐like cells (odontoclasts). In this study, we examined the expression of RANKL and osteoprotegerin (OPG), a decoy receptor that prevents RANKL from binding to RANK in human periodontal ligament (PDL) cells during physiological root resorption using immunocytochemistry and reverse transcriptase polymerase chain reaction. The effect of RANKL on root resorbing activity of odontoclasts was evaluated by measuring the size of dissolved area on calcium phosphate‐coated coverslips. The PDL cells isolated from either non‐resorbing deciduous teeth or permanent teeth abundantly expressed OPG, but not RANKL. In contrast, PDL cells derived from resorbing deciduous teeth dominantly expressed RANKL. Human odontoclasts derived from resorbing deciduous teeth expressed both RANKL and RANK. It was observed that RANKL increased odontoclast actin ring formation and resorbing activity in a dose‐dependent manner. These results indicate that PDL cells during the root‐resorbing state express RANKL but decrease OPG expression. Expression of RANKL likely participates in odontoclastogenesis and activates physiological root resorption.
Ecology of oral health: a complexity perspective
Authors: Eriksen Harald M. , Dimitrov Vladimir
Published: July 2003

Health and disease are determined by many interwoven factors. Complexity theory may facilitate an understanding of oral health and disease by studying their complex interplay, and not focusing only on the importance of each individual factor involved. This introduces a theoretical basis for a dynamic, holistic approach to oral health with possible far‐reaching consequences for dental education and diagnosis, prevention and treatment of oral diseases.
Relationship between dental health and 10‐year mortality in a cohort of community‐dwelling elderly people
Authors: Hämäläinen Piia , Meurman Jukka H , Keskinen Marja , Heikkinen Eino
Published: July 2003

Dental examinations were carried out as part of the Evergreen project, which focuses on functional capacity and health among the elderly residents of the city of Jyväskylä, central Finland. Dental status was examined in 1990 for the whole population born in 1910 (n = 226). Mortality data were collected over 10 yr. The aim of the study was to assess the possible role of dental health as a predictor of mortality. The Kaplan–Meier method was used to analyse survival curves and Cox regression models, with the number of chronic conditions and self‐rated health used as covariates in analysing the risks of death. The results showed that the more teeth or filled teeth a subject had, the smaller was their risk for death. The effect of missing teeth was significant after adjusting for the general health variables. Thus, our results support the hypothesis that poor dental health is linked to increased mortality among elderly people.