Iron-loaded PLLA nanoparticles as highly efficient intracellular markers for visualization of mesenchymal stromal cells by MRI.

Monitoring of the fate of cells after injection appears paramount for the further development of cell therapies. In this context magnetic resonance imaging (MRI) is increasing in relevance owing to its unique tissue visualization properties. For assessment of cell trafficking and homing, the cells have to be labeled to become MR visible. The rather low sensitivity of MRI demands dedicated intracellular markers with high payloads of MR contrast agents for ensuring sensitive detection of local cell aggregations. In the presented work the application of custom-designed nanometer-sized iron oxide loaded poly-(l-lactide) (iPLLA) nanoparticles was investigated. The particles were synthesized by the mini-emulsion process and evaluated for labeling of mesenchymal stromal cells (MSCs). The efficient cellular uptake and long intracellular retention times of the particles as well as their nontoxicity are demonstrated. The average cellular iron content was 55 pg iron per cell. Further incorporation of, for example, fluorescent dye enables the generation of multireporter particles, providing the great potential for multimodal imaging. The efficiency of these nanoparticles as MRI contrast agent was evaluated in vitro using relaxation rate mapping, yielding relaxivities r2 = 273.3, r2 (*) = 545.1 mm(-1) s(-1) at 3 T and r2 = 415.7, r2 (*) = 872.3 mm(-1) s(-1) at 11.7 T. The high r2 (*) relaxivity of the iPLLA nanoparticles enabled visualization of a single labeled cell in vitro at 50-µm spatial resolution. In vivo evaluation in a rat injury model revealed the potential of the iPLLA particles to efficiently label MSCs for MRI monitoring of ~20 000-40 000 injected cells at 11.7 T. In conclusion the presented work demonstrates the applicability of iPLLA particles as efficient intracellular marker for MSC labeling for monitoring the fate of the cells by MRI.

[Transoral miniplate osteosynthesis of mandibular condyle fractures--optimizing the surgical method]. / Die transorale Miniplattenosteosynthese von Gelenkfortsatzfrakturen--Optimierung der operativen Methode.

Under certain conditions dislocated low subcondylar fractures of the mandible can be reset by intraoral approach and treated using miniplate osteosynthesis. This approach protects the facial skin as well as Ramus marginalis. Over a period of 30 months, the authors performed this surgery on 34 patients with dislocated low subcondylar fractures of the mandible. This approach requires a 90 degree drill and screw device, a special resetting hook and retractors. The surgery is performed preferably under endoscopic viewing conditions. The results show that transoral miniplate osteosynthesis is technically feasible, representing a recommended therapy considering the particular indication and requiring the equipment specified above.

[War injuries of the mandible and sequelae 50 years later]. / Kriegsverletzungen am Unterkiefer und ihre Folgen 50 Jahre später.

About 50 years after the end of World War II 84 former soldiers of the German army were examined for aftereffects of their war injuries. Among the data recorded for analysis were the age at which the injury was incurred, the examination intervals, the region affected by the injury and the cause of the injury, but also the different levels of aftereffects of injuries. A total of 53 applicants had suffered mandibular injuries. Considering the wide scattering range, it can be concluded that values of about 20 percent represent a mean degree of incapacitation, primarily due to a combination of loss of teeth and parts of the alveolar process and the effects on the prosthetic support. Casuistic examples illustrate special histories or developments including sarcomagenesis in the region originally affected by the injury.

[Surgical therapy of oropharyngeal carcinoma within the scope of interdisciplinary tumor surgery]. / Die operative Therapie des Oropharynxkarzinoms im Rahmen der interdisziplinären Tumorchirurgie.

BACKGROUND: The results of the surgical therapy of patients with extensive squamous cell carcinoma of the oropharynx and their lymph node metastasis, postoperative follow-up, and rehabilitation depend on the collaboration between ear, nose, and throat surgeons and maxillofacial surgeons. Modern reconstruction techniques permit single-session surgical treatment with a reduced period of hospitalization. The most important therapeutic aim is to improve patient well-being. PATIENTS: Over a period of two years, 45 patients underwent the same surgical procedure. These patients were all in stages III or IV of their disease. RESULTS: This procedure consists of a temporary lateral osteotomy of the mandible with or without resection of the mandible, to provide broad exposure of the tumor of the oropharynx. Apart from the broad exposure, the advantage of this surgical method lies in simple reconstruction using a pedicled and microanastomosed flap. Internal fixation with six and four-hole titanium plates is a reliable method for restoring the stability of the mandible. In six patients, complications occurred in connection with the plate fixation. In four patients, we observed osteomyelitis of the fragment fissure or sequestration. Plate fracture and pseudarthrosis occurred in one patient each. CONCLUSIONS: In our clinical experience, the microvascular anastomosed radial flap proved to be the ideal free soft tissue transplant. One of its primary advantages is its plasticity and hence good post-therapeutic functional results. The jejunal flap has become less significant them the radial flap; the advantage of mucous membrane transfer is lost after radiation and a corresponding postoperative interval. In patients with large, voluminous defects, the use of myocutaneous flaps, especially from the latissimus dorsi, is still justified.

[Desmodont remains after tooth extraction in digital image processing]. / Restdesmodont nach Zahnextraktion in digitaler Bildverarbeitung.

Breakage of the dentoalveolar gomphosis during tooth extraction results in varying amounts of desmodont remaining at the surface of the root. By dying the remnants of desmodont with toluidine blue, the surface of the root can be made accessible to computerized optical analysis. After clinically induced extraction of 102 human teeth, and after the loosening of 24 sheep teeth by mechanical vibration, the remaining area of desmodont was compared to that of the entire surface. Except in one case, no parameters were found to influence the amount of desmodont. However, tooth extraction in sheep previously treated with ultrasound or low-frequency vibrations demonstrate more desmodont-free areas.

[Contribution to the standardization of intraoral radiography technics]. / Beitrag zur Standardisierung der intraoralen Röntgenaufnahmetechnik.

Many practices are available for placing a dental radiographic film in the mouth. A uniform system is proposed to make the best of the advantages offered by the standarization of the intra-oral X-ray technique.

[Mandibular refractures]. / Refrakturen des Unterkiefers.

The portion of individuals with mandibular refractures in traumatized patients is but small. During a period of more than 10 years, 16 male patients presented once more with a mandibular fracture. In five of these patients, the mandibular fracture was a true refracture. Apart from problems by which experts are confronted in such cases, special attention is given to the epileptic who is at risk of trauma.

[Intraosseous screw splinting of mandibular fragments]. / Intraossale Verschraubung von Fragmenten des Unterkiefers.

Fractures in the frontal region of the mandible may be treated by intra-ossal splinting without the risk of injuring nerves or vessels. Function-stable fixation of the reposited fragments was achieved in 15 patients by means of a transfragmental screw with metric thread. The advantages of this procedure consist in the easy removability of the material and the superfluidity of new developments of material or instruments. As the possibility of early functional treatment prevents the late impairment of the articular function, this procedure is particularly indicated in case of concurrent paramedian and articular fractures.

[Simultaneous treatment of anomalies during manafement of fractures in the maxillofacial region]. / Zur Frage der gleichzeitigen Behandlung von Anomalien bei der Versorgung von Frakturen im Kiefer-Gesichts-Bereich

Any schematism in choosing an operating technique is inappropriate in the surgical treatment of anomalies alone. This is all the more true in case of concomitant facial bone fractures which require all sorts of combinations and variations of the known procedures. None of the 13 patients who had presented during the years 1969-1973 with a maxillofacial fracture and an anomaly was subjected to the same kind of operation (with regard to osteotomy and ostectomy). An asymmetrical approach had to be adopted in almost any case to accomodate to the precautions required in the surgical treatment of the anomaly as well as to the demands on fracture management.