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Biomedical subjects

E K Basdra

Publications and source records attributed to E K Basdra.

At least 19 recordsLinked to original sources
PubMed2005

The MAPK-AP-1/-Runx2 signalling axes are implicated in chondrosarcoma pathobiology either independently or via up-regulation of VEGF.

AIMS: To investigate whether and how the JNK/ERK-AP-1/-Runx2 signalling pathways and vascular endothelial growth factor (VEGF) are engaged in the pathogenesis of cartilaginous tumours. Chondrosarcoma is the third most common primary skeletal malignancy. Nevertheless, the molecular events underlying its pathogenesis remain elusive. JNK/ERK MAPKs and their downstream effectors, c-Jun and c-Fos (AP-1), are involved in chondroblastic differention/proliferation. These proteins interact with the Runx2 transcription factor, which is also implicated in chondroblast biology. VEGF, a key angiogenic factor, is up-regulated in human chondrosarcomas. METHODS AND RESULTS: Normal cartilage and neoplastic cells from 45 chondrosarcomas and 21 enchondromas were investigated immunohistochemically. We evaluated the cellular levels of JNK2, p-JNK2 (phosphorylated/activated JNK2), its main substrate, c-Jun, pc-Jun (phosphorylated/activated c-Jun) and c-Fos. Moreover, the levels of p-ERK (phosphorylated/activated ERK), Runx2 and VEGF were assessed. Positive immunostaining for all proteins was observed in the majority of the examined chondrosarcomas and in a small fraction of enchondromas. The expression levels of all proteins were positively and significantly correlated with each other. These levels were substantially augmented in high-grade compared with low-grade chondrosarcomas and in low-grade tumours compared with benign enchondromas, implying a potential use as molecular markers for prediction of high-grade neoplasms. CONCLUSIONS: The JNK/ERK-AP-1/-Runx2 signal transduction 'network' is associated with chondroblastic malignant transformation and chondrosarcoma development, either separately or through coordinated induction of VEGF.

Adult↗
PubMed2001

Congenital tooth anomalies and malocclusions: a genetic link?

The aim of the present study was to investigate putative relationships between different malocclusions such as Class III and Class II division 1, and congenital tooth anomalies. Two-hundred Class III and 215 Class II division 1 patients were examined for the presence of any of the following congenital tooth anomalies: maxillary incisor hypodontia, maxillary canine impaction, transpositions, supernumerary teeth, and tooth agenesis. Their occurrence rates were then calculated as a percentage of the total sample and were compared for statistical differences. The results revealed no statistical difference (P > 0.05) in the occurrence rates of upper lateral incisor agenesis, peg-shaped laterals, impacted canines, or supernumerary teeth between the Class III and the Class II division 1 malocclusions. When the occurrence rate of all congenital tooth anomalies was compared between the two malocclusions, Class III subjects showed significantly higher rates (P < 0.05). Comparison with published surveys on general populations showed similar occurrence rates. It can be concluded that subjects with Class III and Class II division 1 malocclusions show patterns of congenital tooth anomalies similar to those observed in the general population. Congenital tooth anomalies may represent another criterion for the study of malocclusion, with respect to their origin and development.

Adolescent↗
PubMed2001

Stretch-mediated activation of selective MAPK subtypes and potentiation of AP-1 binding in human osteoblastic cells.

BACKGROUND: It is widely accepted that mechanical loading is necessary to construct the architecture of bone and to maintain bone mass. However, the molecular mechanisms whereby bone cells respond to mechanical stimuli remain elusive. The mitogen-activated protein kinase (MAPK) signaling cascades are known to play a crucial role in the immediate osteoblast response to a variety of bone-active agents. An important component of this response occurs at the transcriptional level and is executed by downstream phosphorylation substrates, most notably, a number of signal-responsive transcription factors. To identify whether the MAPKs are involved in the mechanotransduction process and to determine the effect on down-stream transcription factors, we stimulated human periodontal ligament (hPDL) osteoblast-like cells by mechanical stretching by employing an established in vitro model of continuous stretch application. MATERIALS AND METHODS: Whole-cell extracts were prepared from cultivated hPDL cells that were exposed to short-term, continuous mechanical stretch. In-gel kinase assays were used to assess their kinase activity towards the immediate-early gene products c-Jun and c-Fos [constituents of the activator protein-1 (AP-1) transcription factor]. Electrophoretic mobility-shift and southwestern experiments utilizing a DNA sequence that contained a previously undefined atypical AP-1-binding site in the promoter of the human liver/bone/kidney alkaline phosphatase (L/B/K ALP) gene (an early marker for osteoblastic differentiation) were employed to evaluate their specific binding capacity. RESULTS: Selective members of the MAPK family were rapidly induced by stretching, as manifested by their ability to enhance phosphorylation of their cognate substrates c-Jun and, to a lesser extent, c-Fos in the in-gel kinase assay. This induction was accompanied by markedly increased, phospho-c-Jun-containing AP-1-binding activity, as determined by the binding analyses performed with the relevant sequence from the L/B/K ALP promoter. CONCLUSIONS: In as much as AP-1 is instrumental in regulating genes activated at the onset of osteoblast differentiation, such as the ALP gene, we pose that an interplay of distinct MAPKs targeting AP-1 components may dictate the osteogenic response of hPDL cells to mechanical stimulation.

Alkaline Phosphatase↗
PubMed2000

The Class II Division 2 craniofacial type is associated with numerous congenital tooth anomalies.

The aim of the present study was to examine whether a putative relationship exists between the Class II division 2 craniofacial type and congenital anomalies of the dentition, such as missing teeth, peg-shaped laterals, transpositions, supernumerary teeth and canine impactions. Two hundred and sixty-seven untreated patients with Class II division 2 malocclusion were examined. The results show that 56.6 per cent of the patients exhibited some form of congenital tooth anomaly, 13.9 per cent agenesis of the upper lateral incisors, 7.5 per cent peg-shaped upper laterals, while impacted canines were present in 33.5 per cent of the subjects. Transpositions were present in 1.1 per cent of the patients and in all cases the canine was involved. No patient exhibited a supernumerary tooth. Comparing the results of the present study with existing data on the percentage of congenital tooth anomalies in the general population, it can be concluded that Class II division 2 malocclusions are closely associated with congenital tooth anomalies.

Adolescent↗
PubMed1999

Transmission and scanning electron microscopic analysis of mineralized loci formed by human periodontal ligament cells in vitro.

Fibroblasts isolated from human periodontal ligament (PDL) were cultured under a medium supplemented with ascorbic acid, beta-glycerophosphate and dexamethasone. The cultures were assessed for their ability to elaborate a mineralized matrix. Cell cultures stained positive when analyzed for alkaline phosphatase activity throughout the culture period. After about 3 weeks in culture, the cells produced a calcified matrix. Light microscopy showed formation of clusters of different shapes and sizes. Von Kossa staining revealed mineral deposits as amorphous brown-black precipitates. Transmission electron microscopy showed cells in multilayers and mineralized formations in close association with a dense network of collagen fibers. Scanning electron microscopy revealed smooth formations rising over the cultures with an abundant fiber matrix. We conclude that human PDL fibroblasts can be induced to form a mineralized matrix which shares features with bone mineralized matrix but most likely represents a more immature type of in vitro mineralization. Moreover, the present study further supports the osteoblastic potential of these cells.

Calcification, Physiologic↗
PubMed1999

Extraction therapy in patients with Class II/2 malocclusion.

The aim of this study was to analyze the dynamic development of Class II, Division 2 malocclusion with reference to the untreated patients from the Belfast Growth Study. As a second step, the influences of premolar extraction in all 4 quadrants and of maxillary second molar extraction in the upper jaw in Class II/2 patients were examined, focusing on the cephalometric variables in comparison to those of the untreated patients from the Belfast study. The longitudinal cephalometric values of 20 patients in each group were compared. In addition, the possibility of third molar eruption was evaluated in the extraction patients from the panoramic radiographs. The overbite based on study models at the beginning and end of treatment was calculated. Furthermore, renewed spacing after premolar extraction was assessed. The results derived from cephalometric analysis demonstrated that profile flattening was also observed in untreated Class II/2 patients during the growth period. Comparison of these data with those obtained from the extraction groups revealed a significantly marked recession of the upper lip after premolar extraction. In contrast, only slightly increased flattening after maxillary second molar extraction was observed compared with the untreated patients of the control group. Whereas the interincisal angle was reduced to a value approximating that of untreated Class I patients after maxillary second molar extraction, only a small decrease was recorded after premolar extraction. From our point of view, the claim that premolar extraction facilitates third molar eruption should be seen in an extremely critical light and should not contribute to the decision in favor of extraction. In addition, there is a problem of renewed spacing in the extraction area after premolar extraction.

Adolescent↗
PubMed1999

Elastic activator for treatment of open bite.

This article presents a modified activator for treatment of open bite cases. The intermaxillary acrylic of the lateral occlusal zones is replaced by elastic rubber tubes. By stimulating orthopaedic gymnastics (chewing gum effect), the elastic activator intrudes upper and lower posterior teeth. A noticeable counterclockwise rotation of the mandible was accomplished by a decrease of the gonial angle. Besides the simple fabrication of the device and uncomplicated replacement of the elastic rubber tubes, treatment can be started even in mixed dentition when affixing plates may be difficult.

Acrylic Resins↗
PubMed1999

Factors influencing changes in maxillary arch dimensions in unilateral cleft lip and palate patients until six months of age.

OBJECTIVE: The objectives of the present study were (1) to investigate whether growth increments until 6 months of age are influenced by particular factors, (2) to analyze whether anterior cleft reduction is dependent on the extent of the cleft width at birth, and (3) to examine the correlation between maxillary measurements at birth and the anterior cleft width at 6 months of age. DESIGN: The study design was prospective and longitudinal. SETTING: Heidelberg University Hospital Interdisciplinary Cleft/Craniofacial Center. PATIENTS AND METHOD: The longitudinal records of 34 patients (24 male and 10 female) with complete unilateral cleft lip, alveolar ridge, and hard and soft palate were included in this study. All patients were treated with the same protocol. All participants were assessed at 0 and 6 months of age. Maxillary plaster casts of the patients were analyzed using a computer-controlled three-dimensional digitizing system. MAIN OUTCOME MEASURE: Maxillary models were measured and compared to putative factors influencing growth. RESULTS: No statistically significant differences were found between maxillary growth changes and increases in weight and length. Similarly, there was no significant interaction between the extent of the alveolar cleft width at birth and its reduction prior to lip closure. In contrast, significant differences of maxillary growth increments could be found between male and female patients. Stepwise regression analysis demonstrated a correlation between maxillary measurements at birth and growth increments. CONCLUSION: The results of the study indicate that gender plays a certain role in growth changes within the first 6 months of age.

Aging↗
PubMed1998

Mechanical stress induces DNA synthesis in PDL fibroblasts by a mechanism unrelated to autocrine growth factor action.

Periodontal regeneration is thought to require the proliferation of stress-sensitive periodontal ligament (PDL) fibroblast cells. The influence of physiological amounts of mechanical stretching on the DNA synthesis potential of human PDL fibroblasts was examined by means of an established, simple in vitro system of stretch application. A significant increase in the relative levels of incorporation of tritiated thymidine was observed in cultures stretched for 1-6 h. Neutralising antibodies for platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) did not blunt the DNA synthesis induction. This mitogenic response to stretch appears to be independent of an autocrine mechanism involving growth factors in general, because stretch-conditioned medium, when transferred to non-stretched fibroblasts, did not mimic the mitogenic effect of stretch.

Culture Media, Conditioned↗
PubMed1998

Functional treatment of condylar fractures in adult patients.

Functional treatment of condylar fractures in adult patients usually follows the closed reduction/maxillomandibular fixation approach. Some of the problems arising when functional appliances (i.e., activator) are used have been identified and presented here, especially in patients where fractured parts are dispositioned/dislocated. The cause is discussed and a different functional approach is proposed that yields good results.

Activator Appliances↗
PubMed1998

The importance of the maxillary sinuses in facial development: a case report.

A case of mandibular asymmetry is presented. It appears that in this patient the mandible was adapted to changes in the maxillary sinus area. Abnormal bone growth of unknown aetiology inside the sinus most likely caused complete remodelling in the maxillary sinuses and asymmetry of the mandible. Special tests used for detailed assessment of the patient supported the definitive diagnosis.

Adult↗
PubMed1998

Non-surgical treatment of upper airway obstruction in oculoauriculovertebral dysplasia: a case report.

A non-surgical technique for the treatment of upper airway obstruction in oculoauriculovertebral dysplasia using an intra-oral orthopaedic appliance is described, which resulted in respiratory and feeding problems being solved without side-effects. This non-invasive management might also be of major benefit in the treatment of airway obstruction associated with Pierre Robin sequence, mandibular micrognathia in other craniofacial anomalies, or obstructive sleep apnoea.

Airway Obstruction↗
PubMed1997

Mesiodentes: incidence, morphology, etiology.

There are many publications in the literature focusing on clinical, radiological and surgical aspects of the treatment of mesiodentes. However, the etiology of this dental anomaly remains widely unclear. The purpose of this study was to evaluate etiologic factors for mesiodentes in a collective comprising 30 patients with a total of 45 mesiodentes. Thirty-one percent of the patients showed a familial disposition, pointing to inheritance as a key factor in the development of mesiodentes. Our results further support the hypothesis of related etiologic factors for several dental and craniofacial anomalies, such as hyperdontia, hypodontia and cleft lip and palate. Finally, we report the gemination of a deciduous incisor on the same side as a mesiodens. We also found differences in the mesiodistal width of central incisors depending on unilateral or bilateral occurrence of mesiodentes. Both these findings support the dichotomy theory of the split in the tooth bud inducing the development of mesiodentes, a theory we favor over that of local hyperactivity of the dental lamina.

Craniofacial Abnormalities↗
PubMed1997

Osteoblast-like properties of human periodontal ligament cells: an in vitro analysis.

Identifying the biological properties of the cells residing within the periodontal ligament (PDL) will help in understanding the role that these cells play in the various functions of the periodontal ligament, and will improve the success of clinical procedures such as orthodontic tooth movement. For this purpose, fibroblasts isolated from human periodontium were cultured and characterized both histochemically and biochemically with respect to their putative osteoblast-like properties. Histochemically, cultured PDL fibroblasts showed an intense staining for alkaline phosphatase (ALP). Biochemically, the basal ALP activity increased in culture over time. ALP levels after stimulation with 1 alpha, 25-dihydroxyvitamin D3 were significantly higher than those of control cultures. Moreover, immunofluorescence against osteocalcin (a highly reliable osteoblastic marker) was strongly positive. Von Kossa staining of the cell cultures revealed the formation of mineral-like nodules. These results indicate that human PDL fibroblasts exhibit in vitro phenotypic characteristics consistent with osteoblast-like cells, thus suggesting that such cells have the potential to differentiate into osteoblasts and/or cementoblasts.

Alkaline Phosphatase↗
PubMed1997

A combined surgical and orthodontic treatment of Class III furcations. Report of a case.

Oral hygiene in furcation defects of upper molars is difficult to achieve. In this case report, a combined surgical and orthodontic treatment procedure is presented to facilitate access and plaque control in furcation areas of upper molars with class-III furcation defects. After endodontic treatment and root resection in an upper 1st molar, the remaining mesiobuccal and palatal roots were separated and aligned orthodontically within the dental arch, as one-rooted teeth. The new morphological position of the roots greatly facilitated oral hygiene and may offer a better long-term prognosis.

Dental Plaque↗
PubMed1997

Early maxillary orthopedics in a child with an oblique facial cleft.

OBJECTIVE: Oblique facial clefts are extremely rare. In view of their variability, surgical treatment cannot be standardized. To date, early maxillary orthopedics in the treatment of oblique facial clefts have not been reported. The case described here presents a newborn child with a Tessier 3 cleft. Because of the enormous width of the alveolar cleft, a narrowing of the segments was regarded as prerequisite for definitive lip closure. To bring the segments together, an actively working plate with a forward pull was designed. CONCLUSION: After a period of 4 weeks, proper alignment and proximity of the segments were achieved, so that definitive lip closure and plastic reconstruction of the remaining soft tissue defect could be easier performed.

Abnormalities, Multiple↗
PubMed1997

Biological reactions to orthodontic tooth movement.

Understanding the biological basis of tooth movement is crucial to orthodontics. Identifying the components of the signal transduction pathway initiated after force application will permit their manipulation, leading to better results. To examine the effects of mechanical stimulation in the periodontium, human periodontal ligament cells were isolated, cultured and characterized. In contrast to gingival fibroblasts, human PDL-fibroblasts in culture exhibit characteristics typical of osteoblast-like cells. To assess the role of mechanical stimulation the relevant orthodontic forces were simulated in vitro. For this purpose PDL-cells were cultured in Petri dishes with a flexible bottom. This bottom can be stretched over a convex template so that the adherent cells will be also stretched. The results of the stretching experiments demonstrate that human PDL-cells respond to mechanical stretch by a signal transduction pathway which most likely includes specific small GTP-binding proteins, such as Rab and Rho, as well as well defined transcription factors (c-Jun and c-Fos).

Biomechanical Phenomena↗