Clinical risk factors and evaluation of the risk of osteoporosis in clinical practice

Bone health is determined by influences that accumulate over one's entire lifetime. Numerous factors including age, heredity, nutrition, physical activity, sex steroids and other medical problems all influence the possibility of an individual developing osteoporosis. Fractures due to minimal trauma are the important consequence of osteoporosis, but the risk of fractures is also determined by many non-skeletal risk factors such as body size and the frequency of injury. We now have effective therapeutic options to prevent bone loss and to reduce fracture risk. Assessing risk factors for both osteoporosis and for fractures allows clinicians to identify individuals for whom these therapies are most appropriate.     

Untersuchung zur Kategorisierung des mandibulären Wachstumspotentials von Petrovic,Lavergne und Stutzmann

Zusammenassung In der vorliegenden Studie sollte untersucht werden, ob die vonPetrovic, Lavergne undStutzmann vorgeschlagene Kategorisierung des mandibulären Wachstumspotentials für die Behandlung mit dem Funktionsregler Geltung hat. Dazu wurden die Fernröntgenaufnahmen von 140 Patienten der Angle-Klasse II nach zirka zweijähriger Behandlung mit Funktionsreglern analysiert. Im Vergleich zu 133 unbehandelten Kindern mit Angle-Klasse II trat in fast allen Rotationsgruppen eine signifikant größere Zunahme der Unterkiefergesamtlänge ein. Zwischen der Kategorie 2 mit niedrigem Wachstumpotential und Kategorie 5 mit hohem Wachstumspotential wurden keine signifikant unterschiedlichen Zunahmen der Unterkieferlänge festgestellt.

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Summary The results of the study show whether the classification of mandibular growth potential, as proposed by Petrovic, Lavergne and Stutzmann has any influence on the treatment with a function regulator. X-rays of 140 class II patients were analysed after a treatment time of approximately 2 years. In comparison with 133 class II children without any treatment, a significant increase of the overall mandibular length was observed in almost all children treated. There was no significant difference in the increase of mandibular length between category 2 (low growth potential) and category 5 (high growth potential).

     

Fluorinated surface-modifying macromolecules: modulating adhesive protein and platelet interactions on a polyether-urethane

Polyether-urethanes (PEUs) have been the materials of choice for the manufacture of conventional blood-contacting devices. Nevertheless, biostability and blood compatibility are still among the principal limitations in their long-term application. Studies investigating the development of protective coatings for PEUs have shown that degradation can be reduced with the use of fluorinated surface-modifying macromolecules (SMMs). It has also been hypothesized that SMM-modified PEU surfaces may exhibit improved blood compatibility because other studies have shown a modulation in fibrinogen adsorption onto these surfaces. To determine the blood compatibility of a PEU-containing fluorinated SMMs, a series of in vitro experiments were designed to study the pattern of protein adsorption from plasma and then to assess the nature of platelet adhesion and activation on each substrate. Western blot analysis as well as single protein studies revealed that the dominant "adhesive proteins" [fibrinogen (Fg), fibronectin (Fnc), and vitronectin (Vnc)] were adsorbed on two of the SMM-containing PEUs in lower amounts relative to unmodified base. Platelet adhesion and activation data further highlighted the differences among the various substrates. It was shown that the unmodified base had a higher number of adhered platelets relative to the SMM-modified surfaces, and that of the SMM-containing substrates, which showed the lowest levels of adhesive proteins also, exhibited significantly lower platelet densities. Close morphological examination further revealed that platelets residing on these latter substrates were not appreciably activated. Based on the current evidence, it is believed that the fluorinated SMMs demonstrate good potential for the development of surfaces with minimal thrombogenic character in in vivo applications.     

Adsorption of plasminogen from human plasma to lysine-containing surfaces

The objective of this work is to develop blood-contacting surfaces that will dissolve nascent clots that may begin to form on them. Surfaces were prepared consisting of a polyurethane to which a coating reagent was attached covalently by photochemical methods. The coating reagent was a polyacrylamide with lysine and benzophenone (for photochemical attachment) moieties pendant to the chains. It was hypothesized that via the lysine moieties such surfaces would show specific binding affinity for plasminogen, the principal component of the fibrinolytic system in blood. Surfaces of varying lysine content in which the lysine was bound through the alpha-amino groups, leaving the epsilon-amino groups free, were investigated. A control surface in which the lysine was bound through the epsilon-amino groups was also examined. Advancing water contact angles showed the surfaces to be hydrophilic. Hydrophilicity was found to decrease as the lysine content increased. Adsorption of plasminogen from plasma was studied using radioiodinated plasminogen as a tracer. For the epsilon-lysine surfaces, adsorption increased with increasing lysine content and reached a value of 1.2 microg/cm(2) for the surface with the highest lysine content, that is, in the range expected for a compact monolayer of plasminogen. The control surfaces, which contained either no lysine or lysine in which the epsilon-amino groups were unavailable, adsorbed very small amounts of plasminogen. Immunoblots were obtained for the proteins eluted from the surfaces after incubation with plasma. For the control surfaces, most of the proteins tested for (some 20 in all) were present. However, for the surface containing the highest concentration of epsilon-lysine, only plasminogen was detected in a significant amount. It is concluded that the epsilon-lysine surface adsorbs plasminogen to the exclusion of the other plasma proteins. Studies to examine the fibrinolytic properties of these surfaces will constitute the next phase of this work.