Platelet-rich fibrin (PRF) is prepared from whole blood without any exogenous coagulation factors. Several preparation methods have now been introduced, particularly with differences in centrifugation parameters including g-force and time to improve their regenerative potential. Nevertheless, the centrifugation systems have not yet been clearly investigated for their influences on the PRF clot properties. The aim of the present study was to visually and histologically characterize the cell separation manner and blood cell localization on the whole PRF clots prepared by two different centrifugation system, fixed-angle and horizontal centrifugation. Leukocyte- and platelet-rich fibrin (L-PRF) was prepared on a fixed-angle centrifuge machine (IntraSpin, Intra-Lock, FL, USA) at 2700 rpm (~400 g at the RCF-clot; ~700 g at the RCF-max) for 12 min. The PRF prepared by horizontal centrifugation was prepared on a horizontal centrifugation (H-PRF) (Eppendorf 5702, Eppendorf, Germany) at 700 g at the RCF-max for 8 min. The cell morphology and localization were observed on the surface of PRF clots by scanning electron microscopy (SEM) and histologically by transaxial frozen sections by means of a film method. L-PRF clots demonstrated a sloped separation between the upper plasma and the bottom red blood cell (RBC) layers according to the angle of the rotor. Red dots were often observed on the distal walls of the tubes in the upper layers, consisting of aggregations of RBCs, leukocytes and platelets by SEM and histology. Clots produced on the horizontal centrifuge showed much smoother cell layer distribution/separation along the tube surfaces when compared to L-PRF. Horizontal centrifugation also demonstrated more evenly distributed platelets throughout the PRF clots when compared to L-PRF that gathered the majority of cells along the distal tube surface or within the buffy-coat region. In summary, it was found that horizontal centrifugation resulted in a more uniform blood cell separation of PRF clots when compared to the accumulation of cells gathered along the distal tube surfaces produced prepared by fixed-angle centrifugation. Future research is needed to evaluate the benefit of horizontal centrifugation in clinical practice.
Extracorporeal irradiation sterilizes resected tumor bone used as autografts in reconstruction surgery. Therapeutic irradiation is a standard technique in head and neck cancer therapy that aims to preserve organ function. Bone irradiation has a complex, mostly inhibitory, effect on remodeling and regeneration, although the underlying mechanisms are still not fully understood. It remains unclear if extracorporeal irradiation affects the paracrine-like activity of the corresponding autografts. We recently reported that bone-conditioned medium from autogenous bone chips contains a number of factors that might affect cell activity. In the present study, we investigated the effects of extracorporeal irradiation of porcine cortical bone chips on the activity of the corresponding bone-conditioned medium. The effects of bone-conditioned medium on the expressions of transforming growth factor-beta (TGF-β) target genes in oral fibroblasts were assessed. Bone-conditioned medium from bone chips exposed to a total radiation dose up to 120 Gy did not affect expressions of TGF-β target genes, including adrenomedullin, BTB/POZ domain-containing protein 11, proteoglycan 4, NADPH oxidase 4, and interleukin 11, in oral fibroblasts. In conclusion, bone irradiation does not alter the capability of the corresponding bone-conditioned medium to provoke a robust fibroblastic cell response in vitro. (J Oral Sci 58, 325-331, 2016).
Abstract Background Simultaneous implant placement with bone grafting shortens the overall treatment period, but might lead to the peri‐implant bone loss or even implant failure. The aim of this study was to compare the single‐staged to two‐staged implant placement using the bone ring technique. Material and methods Four standardized alveolar bone defects were made in the mandibles of nine dogs. Dental implants (Straumann BL ® , Basel, Switzerland) were inserted simultaneously with bone ring technique in test group and after 6 months of healing period in control group. Animals of both groups were euthanized at 3 and 6 months of osseointegration period. The harvested samples were analyzed by means of histology and micro‐ CT . Results The amount of residual bone decreased while the amount of new bone increased up to 9 months of healing period. All morphometric parameters remained stable between 3 and 6 months of osseointegration period within groups. Per a given time point, median area of residual bone graft was higher in test group and area of new bone in control group. The volume of bone ring was greater in test than in control group, reaching the significance at 6 months of osseointegration period ( P = 0.002). Conclusions In the present type of bone defect, single‐staged implant placement may be potentially useful to shorten an overall treatment period.
Background: Bone morphogenetic protein 9 (BMP9) has previously been characterized as one of the most osteogenic growth factors of the BMP family. To the best of the authors’ knowledge, previous experiments have only used adenovirus transfection (gene therapy). With the recent development of recombinant human BMP9 (rhBMP9), the present study investigates the osteopromotive potential of BMP9 versus rhBMP2 when loaded onto collagen membranes. Methods: ST2 stromal bone marrow cells were seeded onto: 1) control; 2) low‐dose rhBMP2 (10 ng/mL); 3) high‐dose rhBMP2 (100 ng/mL); 4) low‐dose rhBMP9 (10 ng/mL); and 5) high‐dose rhBMP9 (100 ng/mL) porcine collagen membranes. The following parameters were compared among groups: 1) cell adhesion (at 8 hours); 2) cell proliferation (at 1, 3, and 5 days); 3) real‐time polymerase chain reaction for genes encoding runt‐related transcription factor 2; 4) alkaline phosphatase (ALP); 5) bone sialoprotein ([BSP] at 3 and 14 days); and 6) alizarin red staining (at 14 days). Results: rhBMP2 and rhBMP9 demonstrated little effect on cell attachment and proliferation; however, pronounced increases were observed in osteoblast differentiation. All groups significantly induced ALP messenger RNA (mRNA) levels at 3 days and BSP levels at 14 days; however, high‐dose rhBMP9 showed significantly higher values compared with all other groups for ALP levels (five‐fold increase at 3 days and two‐fold increase at 14 days). Alizarin red staining further revealed both concentrations of rhBMP9 induced up to three‐fold more staining compared with rhBMP2. Conclusions: Results indicate that the combination of collagen membranes with rhBMP9 induced significantly higher ALP mRNA expression and alizarin red staining compared with rhBMP2. These findings suggest that rhBMP9 may be a suitable growth factor for future regenerative procedures in bone biology.
Abstract Objectives The aim of this study was to evaluate the osseointegration of implants placed in a single‐staged compared to two‐staged procedure using bone ring technique. Material and Methods In this study were used standardized, vertical alveolar bone defects in dogs. In the test group, dental implants (Straumann BL ® , Basel, Switzerland) were inserted simultaneously with bone ring technique. As control group served implants inserted 6 months following grafting. Implants of both groups were left for an osseointegration period of 3 and 6 months. The peri‐implant bone loss and bone‐to‐implant contact within the bone ring and native bone were analyzed morphometrically. An explorative statistical analysis was performed. Results The peri‐implant bone level remained relatively stable within groups and between groups per given time period. Most of bone apposite on the implant surface in two groups was composed of newly formed bone. A nonparametric analysis of variance (ANOVA) revealed no significant advantage for two‐staged implant placement for new and total bone, except for residual bone ( P = .0084). Furthermore, two groups of implants performed similarly in bone ring and in native bone throughout the observation period. Conclusions In terms of osseointegration, both techniques are likely equally efficient in the present defect model. The single‐staged implant placement with cortical bone grafts warrants further documentation in clinical studies.
Neben der klassischen Whipple (cWhipple) gilt die Pylorus-erhaltende Whipple Resektion (ppWhipple) als Alternativtherapie beim Pankreaskopf- und ampullären Karzinom. Bis anhin existieren jedoch keine definitiven Angaben darüber ob die konservativere ppWhipple Operation tatsächlich identische Kurz- und Langzeitresultate wie die cWhipple Resektion erreicht. Methodik: Wir führten deshalb eine randomisierte prospektive Studie durch an einem nicht selektionierten, konsekutiven Patientengut. Alle relevanten Daten wie Patientendemographie, intraoperative und histologische Befunde (Tumor-Typ und Tumor-Grad) sowie die postoperative Morbidität, Letalität und der Langzeitverlauf wurden analysiert. Resultate: Von 6/96 bis 10/99, wurden 139 Patienten mit Verdacht auf ein Pankreas- oder ampulläres Karzinom randomisiert einer cWhipple oder ppWhipple Operation zugeteilt (intention to treat). 93 dieser Patienten erfüllten die Einschluss- und Ausschlusskriterien und bildeten das Studienkollektiv. Es wurden 51 cWhipple und 42 ppWhipple Resektionen durchgeführt. Es gab keine Unterschiede betreffend Alter, Geschlechtsverteilung, ASA-Klassifikation, Tumortyp und -stadium, Dauer des Intensivstation- und Spitalaufenthaltes zwischen den beiden Gruppen. Die ppWhipple Gruppe hatte eine signifikant kürzere Operationsdauer während Blutverlust und Blutsubstitution nicht verschieden waren. Die postoperative Letalität wie auch die Gesamtmorbidität waren identisch in den beiden Gruppen. Insbesondere war die Inzidenz der Magenentleerungsstörung in beiden Gruppen gleich. Für den Langzeitverlauf wurden 76 Patienten mit histologisch nachgewiesenen pankreatischen oder ampullären Karzinomen analysiert. Es wurde kein Unterschied betreffend Tumorrezidiv und Überleben nach einer mittleren Beobachtungszeit von 1.5 Jahren (Grenzwerte 0.1-3.5), festgestellt. Schlussfolgerung: Unsere vorläufigen Resultate zeigen, dass sowohl die cWhipple als auch die ppWhipple Operation gleich radikal sind. Die ppWhipple Variante könnte damit die Wahloperation für die Behandlung von pankreatischen und ampullären Tumoren sein.
PURPOSE: To clarify the occurrence, causes, severity, and predictors of concomitant injuries in pediatric patients with facial fractures. PATIENTS AND METHODS: Files of 339 pediatric patients who had sustained facial fractures at age 15 years or younger were reviewed. Outcome variables were injured organ systems other than the face, types of injuries in areas other than the face, and severity of injuries in areas other than the face. Explanatory variables were gender, age, mechanism of trauma, and type of facial fracture. RESULTS: Concomitant injuries in organ systems other than the face were observed in 11.0%. Limb injuries occurred in 9.1%, head and neck injuries in 5.6%, and chest injuries in 1.8%. The most common injury types were upper limb injury (8.0%), brain injury (3.2%), and lower limb injury (2.9%). Severe head and neck injuries occurred in 3.5% and severe chest injuries in 1.2%. Concomitant injuries occurred more frequently after motor vehicle accidents and falls from height compared with other etiologies (P Language: en
