Wilfried Kleis

Quantification of Thrombocyte Growth Factors in Platelet Concentrates Produced by Discontinuous Cell Separation

Platelet concentrates (PC) are increasingly used to increase bone regeneration in pre-prosthetic surgery. Although it is generally appreciated that certain growth factors (PDGF, TGF, EGF, and ECGF) are present in thrombocyte preparations, relatively little is known about these components in quantitative terms. The study reported here analysed the amounts of growth factors in PC produced under standard conditions from healthy volunteers. All the blood samples (237 in total) were analysed using Quantikine ELISA kits (R and D). The mean - SD platelet count in whole blood from these donors was 262,000 - 58,000/ w l, while in PC produced by discontinuous cell separation it was 1,419,000 - 333,000/ w l. The mean growth factor concentrations in PC preparations in ng/ml were as follows: PDGF-AB 125 - 55 ng/ml; TGF- g 1 221 - 92 ng/ml; IGF-I 85 - 25 ng/ml; PDGF-BB 14 - 9 ng/ml; TGF- g 2 0.4 - 0.3 ng/ml. These growth factor concentrations typically covered a 3-10 fold range: PDGF-AB 29-277 ng/ml; PDGF-BB 2-33 ng/ml; TGF- g 1 32-397 ng/ml; TGF- g 2 0.1-1.2 ng/ml; IGF-I 40-138 ng/ml. Platelet counts in PC were slightly higher for women (Mann-Whitney Test all p <0.001 ) than for men, while the concentrations of growth factors in PC exhibited no gender-related difference of any statistical significance.

Bone healing with or without platelet-rich plasma around four different dental implant surfaces in beagle dogs.

PURPOSE Surface development is one of the major aims in dental implant engineering. Additive application of substances could possibly improve the new bone formation around dental implants. The present study evaluated the bone reaction on four different implant surfaces with or without platelet-rich plasma (PRP). MATERIALS AND METHODS Four self-tapping titanium screw implants (Brånemark MK III [Nobel Biocare, Göteborg, Sweden], Osseotite [3i, Miami, FL, USA], Xive [Densply Friadent, Mannheim, Germany], and Compress [IGfZ eG, Diez, Germany]) with different surfaces were inserted in each hemimandible of 12 female beagle dogs; the implant positions and the application of PRP were randomized. After intravital fluorochrome staining, sacrifices and biopsies harvesting were performed after 6 weeks (five dogs; one dog died before) and 12 weeks (six dogs) and the respective specimens were analyzed. RESULTS The only significant difference in bone remodeling was found for the Compress implants with increased bone formation compared with the Brånemark implants at 12 weeks (sign test, p = .03). Comparing the histological and histomorphometric specimens of all other implant surfaces with respect to peri-implant bone remodeling and the resulting bone-implant contact rates (BICRs), no statistically significant differences were seen in the PRP or non-PRP groups (sign test, all p values ≥ .063). CONCLUSIONS This study found no significant differences in the BICR for roughened implant surfaces compared with machined surfaces. In this animal model, the addition of PRP did not demonstrate evidence of faster bone formation or the resulting BICR.

Therapy and Prognosis of Extraoral Malignant Melanoma Metastasizing to the Jaw: Case Report and Literature Review

t a d With approximately 75% of all skin cancer-related deaths, malignant melanoma (MM) is the most lethal among common skin cancers, mostly because of its disposition to early lymphogenic and hematogenic metastasis. If a MM is diagnosed early, the overall prognosis is excellent, but once metastasized it becomes an incurable disease with high mortality. Prognosis is dependent on parameters such as gender, anatomic location, level of invasion, thickness, type of primary tumor, ulceration, and number and status of regional lymphatic nodes. For incidence and mortalty, a decrease in young but an increase in older roups—with geographic differences—has been reported. Because of the embryologic origin of melanocytes in the neural crest, MM cannot arise from bone cells. If a MM affects the bone, a primary invasion by local spread or a distant metastasis has to be taken into account. Bones that are frequently involved with metastatic disease are vertebrae, ribs, pelvis, and skull. A etastasis from distant primary tumors to the jaws as been considered a rare disease. It has been shown that about 4% of tumors metastasizing to the jaws are MMs, whereas metastasis of a MM to other bones is found more often. Metastasis of a cutaneus MM to the oral cavity is a very rare incident. In ases of metastasis, the mandible is affected most requently. Radiologically, most lesions appear as os-