Dritan Turhani

Betulinic acid: a new cytotoxic compound against malignant head and neck cancer cells.

A new compound, betulinic acid, has been found to be cytotoxic against a variety of tumor cells originating from the neural crest. Its efficacy against head and neck squamous cellular carcinoma cell lines has so far not been tested.

Initial effects of low-level laser therapy on growth and differentiation of human osteoblast-like cells.

ZusammenfassungDer Einsatz von Soft-Lasern im Rahmen einer Low level-Laser Therapie ist mittlerweile eine klinisch etablierte Behandlungsmethode. In vitro Studien haben gezeigt, dass Soft-Laser auch eine biostimulatorische Wirkung auf unterschiedlichste Zelltypen haben. Das Ziel dieser Untersuchung war die Effekte von Low level-Laser Therapie auf das initiale Wachstums- und Differenzierungsverhalten von in vitro kultivierten humanen osteoblastären Zellen zu untersuchen. SaOS-2 Zellen wurden mit Laser-Dosen von 1 J/cm2 und 2 J/cm2 mit einem Dioden Laser mit 670 nm Wellenlänge und einer Ausgangsleistung von 400 mW bestrahlt. Unbehandelte Zellen dienten als Kontrollgruppe. 24 h, 48 h und 72 h nach der Bestrahlung wurden die Zellen geerntet und ihre Vitalität bestimmt. Zusätzlich wurde die Aktivität der Alkalischen Phosphatase ermittelt und die Expression von Osteopontin und Collagen Typ I mittels semiquantitativer RT-PCR untersucht. Zellen, die mit 1 J/cm2 bestrahlt worden waren wiesen, sowohl eine höhere Vitalität als auch eine höhere Aktivität der Alkalischen Phosphatase gegenüber den Kontrollen auf. Auch die Expression von Osteopontin und Collagen Typ I mRNA war gegenüber der Kontrollgruppe erhöht. Hingegen führte eine Verdopplung der Laserleistung zu einer Abnahme der Zellviabilität in den ersten 48 h und zu einer konstant niedrigeren Alkalischen Phosphataseaktivität. Während die Expression von Collagen Typ I und Osteopontin mRNA in unbehandelten und mit 1 J/cm2 bestrahlten Zellen im Verlauf des Experiments leicht abnahm, konnte eine Zunahme ihrer Expression nach Bestrahlung mit 2 J/cm2 beobachtet werden. Unsere Beobachtungen deuten darauf hin, dass Low level-Laser Therapie eine biostimulatorische Wirkung auf SaOS-2 Zellen bereits in der inititalen Kulturphase hat. Diese Ergebnisse können dazu beitragen, neue Therapie-Konzepte in der Regeneration von Knochendefekten zu entwickeln. Weitere Untersuchungen über einen verlängerten Zeitraum wären hilfreich, dieses Potential genauer zu beurteilen.SummaryLow-level laser therapy is a clinically well established tool for enhancement of wound healing. In vitro studies have also shown that low level laser therapy has a biostimulatory effect on cells of different origin. The aim of this in vitro study was to investigate the initial effect of low-level laser therapy on growth and differentiation of human osteoblast-like cells. SaOS-2 cells were irradiated with laser doses of 1 J/cm2 and 2 J/cm2 using a diode laser with 670 nm wave length and an output power of 400 mW. Untreated cells were used as controls. At 24 h, 48 h and 72 h post irradiation, cells were collected and assayed for viability of attached cells and alkaline phosphatase specific activity. In addition, mRNA expression levels of osteopontin and collagen type I were assessed using semi-quantitative RT-PCR. Over the observation period, cell viability, alkaline phosphatase activity and the expression of osteopontin and collagen type I mRNA were slightly enhanced in cells irradiated with 1 J/cm2 compared with untreated control cells. Increasing the laser dose to 2 J/cm2 reduced cell viability during the first 48 h and resulted in persistently lower alkaline phosphatase activity compared with the other two groups. The expression of osteopontin and collagen type I mRNA slightly decreased with time in untreated controls and cells irradiated with 1 J/cm2, but their expression was increased by treatment with 2 J/cm2 after 72 h. These results indicate that low-level laser therapy has a biostimulatory effect on human osteoblast-like cells during the first 72 h after irradiation. Further studies are needed to determine the potential of low-level laser therapy as new treatment concept in bone regeneration.

Ectopic bone formation in nude rats using human osteoblasts seeded poly(3)hydroxybutyrate embroidery and hydroxyapatite-collagen tapes constructs

PURPOSE The aim of this study was to evaluate the ectopic bone formation using tissue engineered cell-seeded constructs with two different scaffolds and primary human maxillary osteoblasts in nude rats over an implantation period of up to 96 days. MATERIAL AND METHODS Collagen I-coated Poly(3)hydroxybutyrate (PHB) embroidery and hydroxyapatite (HAP) collagen tapes were seeded with primary human maxillary osteoblasts (hOB) and implanted into athymic rnu/run rats. A total of 72 implants were placed into the back muscles of 18 rats. 24, 48 and 96 days after implantation, histological and histomorphometric analyses were made. The osteoblastic character of the cells was confirmed by immunocytochemistry and RT-PCR for osteocalcin. RESULTS Histological analysis demonstrated that all cell-seeded constructs induced ectopic bone formation after 24, 48 and 96 days of implantation. There was more mineralized tissue in PHB constructs than in HAP-collagen tapes (at day 24; p < 0.05). Bone formation decreased with the increasing length of the implantation period. Osteocalcin expression verified the osteoblastic character of the cell-seeded constructs after implantation time. No bone formation and no osteocalcin expression were found in the control groups. CONCLUSIONS Cell-seeded constructs either with PHB embroidery or HAP-collagen tapes can induce ectopic bone formation. However, the amount of bone formed decreased with increasing length of implantation.

The Goslon Yardstick in Patients With Unilateral Cleft Lip and Palate: Review of a Vienna Sample

Objective: To compare a Vienna unilateral cleft lip and palate (UCLP) patient sample with the Eurocleft samples using the GOSLON score, to determine the intra- and interrater agreement between several raters and ratings, and to establish whether training with the original GOSLON models enhances accuracy. Patients and Methods: One hundred twenty-three plaster casts of UCLP patients born between 1970 and 1997, with an average age of 9.2 years and all treated with the same regimen, were rated according to the GOSLON score. Results: Of the patients, 71.5% were ranked GOSLON 1 or 2. Only 8.9% were rated GOSLON 4 or 5. There were no significant differences between the different raters and the ratings. Training with the original GOSLON models increased kappa from 0.57 before training to 0.84 after training. Conclusion: The “Vienna concept” was found to be a good regimen for treating UCLP patients in regard to maxillary growth. Personal training on the original GOSLON models appears to improve the accuracy of rating.

Particle size of hydroxyapatite granules calcified from red algae affects the osteogenic potential of human mesenchymal stem cells in vitro.

Hydroxyapatite (HA) microparticles as a carrier in an injectable tissue-engineered bone filler are considered promising candidates for the treatment of small bone defects in the craniomaxillofacial region. HA granules calcified from red algae, varying in size, were evaluated in vitro for their suitability to be used as a carrier for human mesenchymal stem cells (hMSCs). Three groups of granules were produced in grain sizes of 10–100, 200–500 and 600–1,000 µm. After seeding and culturing hMSCs under osteogenic differentiation conditions onto HA particles for 3, 6 and 9 days, cellular proliferation (tetrazolium salt, XTT), alkaline phosphatase (ALP)-specific activity and total protein synthesis were investigated. The osteoblastic phenotype of the cells was evaluated by assaying the bone-specific genes osteocalcin, osteopontin and collagen type I. XTT assay revealed significantly higher (p < 0.01) proliferation of cells grown on the smallest grain size after 9 days of culture. Regarding ALP-specific activity, significantly higher levels of activity were detected in cells grown on the smallest grain size. Different grain sizes had no significant effects on the secretion of osteocalcin and osteopontin. Collagen type I production was significantly higher (p < 0.05) in cells grown on the biggest grain size in comparison with the two other grain sizes. These results show that the particle size of HA microparticles affects the osteogenic potential of cultured hMSCs and lead to the conclusion that particle size has differential effects on ALP-specific activity and collagen type I production.

Potential involvement of MYC- and p53-related pathways in tumorigenesis in human oral squamous cell carcinoma revealed by proteomic analysis.

Oral squamous cellular carcinoma is a malignant tumor with poor prognosis. Discovery of early markers to discriminate between malignant and normal cells is of high importance in clinical diagnosis. Subcellular fractions from 10 oral squamous cell carcinoma and corresponding control samples, enriched in mitochondrial and cytosolic proteins, as well as blood from the tumor were analyzed by proteomics, two-dimensional gel electrophoresis, followed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Three-hundred and fifty different gene products were identified. Twenty proteins showed deranged levels in oral squamous cell carcinoma in comparison with the control samples and are potentially involved in tumor growth and metastasis. Of these, 16 proteins were upregulated. By applying pathway analysis, we found 8 of the upregulated gene products to be linked to three main locus genes, p53, MYC, and MYCN, and could be candidate biomarkers for OSCC. The findings of this pilot study show that OSCC gene ontology combined with proteomic analysis is a powerful tool in systems biology for the elucidation of the complexity of expression profiles in cellular processes. Application of such pathway analysis has the potential to generate new insights into complex molecular mechanisms underlying disease related processes and could therefore significantly contribute to the efficient performance of the entire discovery process.

Differential Expression Pattern of Cyclooxygenase-1 and -2 in Head and Neck Squamous Cell Carcinoma

Objective—The enzyme cyclooxygenase catalyzes the first step of the synthesis of prostanoids. Cyclooxygenase has been shown to exist in two distinct isoforms: cyclooxygenase-1 is constitutively expressed as a housekeeping enzyme in most tissues whereas the inducible cyclooxygenase-2 has been reported to be involved in inflammatory processes and in the carcinogenesis of squamous cell carcinoma. The aim of this study was to investigate the distribution patterns of cyclooxygenase-1 and -2 in peritumoral lymphocytic infiltrates and tumor cells of head and neck carcinoma. Material and Methods—Immunohistochemical analysis was performed using paraffin-embedded tumor specimens from 24 patients suffering from oropharyngeal, hypopharyngeal and oral squamous cell carcinomas. Results—We observed that cyclooxygenase-2 immunoreactivity, compared to that of cyclooxygenase-1, was significantly increased in peritumoral lymphocytic infiltrates as well as in tumor cells. Conclusion—The expression of cyclooxygenase-2 in both tumor specimens and the surrounding peritumoral lymphocytic infiltrates supports the hypothesis that cyclooxygenase may be one of several important links between chronic inflammation and carcinogenesis.

The Cyclooxygenase-2 Inhibitor Nimesulide, a Nonsteroidal Analgesic, Decreases the Effect of Radiation Therapy in Head-and-Neck Cancer Cells

Background:No data are available on the effects of the cyclooxygenase-2 (COX-2) inhibitor nimesulide in combination with irradiation on the survival of head-and-neck carcinoma cells.Material and Methods:Two head-and-neck carcinoma cell lines (SCC9 and SCC25) were treated with nimesulide (50–600 μM) and irradiated concomitantly or sequentially. Early effects on cell survival were investigated by counting cell numbers, long-term effects by colony-forming assays. Cell-cycle effects were analyzed 24–72 h after treatment with nimesulide by flow cytometry.Results:Unexpectedly, nimesulide solely inhibited cell proliferation without affecting colony-forming ability. In addition, no evidence for a radiosensitizing effect of nimesulide in short-term assays was seen. Nimesulide alone had no effect on clonogenic survival alone or in combination with radiation.Conclusion:Nimesulide differentially affects cell proliferation and clonogenic survival and may decrease the efficacy of radiotherapy. Short-term assays to assess tumor growth may not correctly predict the clinically relevant long-term effect of COX-2 inhibitors.Hintergrund:Bis dato gibt es keine Untersuchungen bezüglich der Anwendung des Cyclooxygenase-2-Hemmers Nimesulid in Kombination mit Bestrahlung auf Zellen des Kopf-Hals-Bereichs.Material und Methodik:Zwei Zelllinien des Kopf-Hals-Bereichs (SCC9 und SCC25) wurden mit Nimesulid (50–600 μM) behandelt und zeitversetzt oder konkomitant bestrahlt. Die Kurzzeiteffekte auf das Überleben der Zellen wurden mittels Zellzählung untersucht, Langzeiteffekte via Koloniebildungsassays. Mittels Durchflusszytometrie wurden die Auswirkungen auf den Zellzyklus 24, 48 und 72 h nach Behandlung evaluiert.Ergebnisse:Nimesulid allein war in der Lage, die Zellproliferation kurzfristig zu hemmen (Abbildungen 1, 2 und 4), allerdings ohne nachhaltigen Effekt auf die Koloniebildungsfähigkeit (Abbildungen 3 und 5). Darüber hinaus konnte weder in den Kurzzeit- (Abbildungen 2 und 4) noch in den Langzeituntersuchungen (Abbildungen 3 und 5) ein die Strahlentherapie unterstützender Effekt nachgewiesen werden.Schlussfolgerung:Nimesulid hat unterschiedliche Effekte auf die Zellproliferation und die Koloniebildungsfähigkeit und könnte die Effizienz der Strahlentherapie schwächen. Weiters bestätigt sich, dass aus Kurzzeitanalysen des Tumorwachstums nicht automatisch auf das klinisch relevante Langzeitergebnis geschlossen werden darf.

Biodegradable polymer membrane used as septal splint

The treatment of a crooked nose is one of the most challenging rhinoplastic procedures. Correction of the abnormally curved or fractured septum has been reported using mostly scoring techniques, septoplasty and submucous resection techniques; cartilaginous spreader grafts can also be sutured to the distorted septum. Extracorporal septal straightening and repositioning/refixation is another useful but difficult technique. A common problem of septal cartilaginous grafting techniques is to harvest enough straight cartilage to correct the deformity. (Other donor sites such as rib cartilage are used, but harvesting additional cartilage is a time-consuming procedure and carries the risk of donor site morbidity.) Recent studies have been published using alloplastic internal splinting of the deformed septum. The use of poly p-dioxanone foils and porous polyethylene has been suggested before. In this study, a novel grafting material, a PolyMax membrane that has potential advantages over both materials, is presented. This is a porous biodegradable polymer made out of 70:30 poly(L-lactide-co-D,L-lactide) that remains stable for at least 7 months. Poly p-dioxanone loses its stability after only 2 months, whereas porous polyethylene is a permeable material that is controversial due to possible complications in cases of membrane exposure and infection. In this preliminary report the PolyMax membrane was used successfully in 3 patients.

Phenothiazine Chloride and Soft Laser Light Have a Biostimulatory Effect on Human Osteoblastic Cells

OBJECTIVE Low-level laser therapy (LLLT) is a well accepted tool to accelerate wound healing and to reduce inflammation after oral implant insertion. Since there are no in vitro data on a combination of LLLT with prior photosensitization, it was the aim of this study to investigate if photosensitization with phenothiazine chloride results in an alteration of the biostimulatory effect of low-level laser irradiation. BACKGROUND DATA LLLT and antimicrobial photodynamic therapy are well established for the treatment of peri-implantitis. In vitro studies have shown a biostimulatory effect of LLLT on various cell types, including osteogenic cells. MATERIALS AND METHODS SaOS-2 cells were treated with the photosensitizer phenothiazine chloride before irradiation with matched laser light. At 24-h intervals the viability and differentiation were analyzed in treated and untreated cells. RESULTS While the biostimulatory effect of the LLLT could be observed for the lower irradiation dose, the pretreatment with phenothiazine chloride did not significantly affect the growth and differentiation of the SaOS-2 cells. CONCLUSION It can thus be concluded that combined treatment with phenothiazine chloride and LLLT does not result in a synergistic enhancement of the biostimulatory effect of LLLT, but there was also no evidence for antagonizing effects on growth and differentiation of human osteoblasts.