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Biomedical subjects

R Clement

Publications and source records attributed to R Clement.

52 records · Page 3Linked to original sources
PubMedDate not supplied

Role of a nonsteroidal anti-inflammatory agent, ibuprofen, in coronary revascularization after acute myocardial infarction.

The efficacy of using a nonsteroidal anti-inflammatory agent such as ibuprofen for the salvage of ischemic and reperfused myocardium was investigated by examining its ability to improve global and regional functions as well as to preserve high-energy phosphate compounds and inhibit creatine kinase release from an isolated in-situ pig heart subjected to 1 h of normothermic regional ischemia followed by 1 h of global hypothermic arrest and 1 h of normothermic reperfusion. Preperfusion of the heart for 15 min prior to ischemic insult with 50 microM ibuprofen failed to mitigate the myocardial reperfusion injury. Ibuprofen, however, functioned as an anti-inflammatory agent, as judged by its ability to inhibit the influx of indium-111-labeled polymorphonuclear leukocytes and chromium-51 (51Cr)-labeled platelets into the ischemic and reperfused heart. It also blocked the cyclooxygenase pathway, as evidenced by the significant reduction of 6-keto-prostaglandin F1 alpha and thromboxane B2 concentrations in the perfusate. Inhibition of cyclooxygenase resulted in increased accumulation of nonesterified fatty acids, particularly arachidonic acid, in the heart. These results suggest that although ibuprofen can inhibit polymorphonuclear leukocyte and platelet influx into the ischemic and reperfused heart, it causes further damage to the already ischemic heart by reducing prostacyclin concentration and increasing free fatty acids in the heart.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

[Concept for development of new individual treatment devices in orthodontics using 3-dimensional numerical simulation of bone remodeling].

The present study is part of a research project that includes different components for the simulation of orthodontic tooth movement and comparing experimental results. This concept includes the development of a bone remodelling algorithm, as well as experimental studies on tooth movement. After the acquisition and evaluation of specific experimental data of the patient's situation, the individual components have to be integrated to verify and forecast tooth movement. The aim is to design individual treatment devices as well as to shorten treatment while making it more effective. The geometry of the teeth and that of the surrounding alveolar bone both influence the orthodontic tooth movement. For this reason, an exact morphological tooth model for the valid simulation of the tooth movement is needed, and can be constructed from computed tomography data. Simulation of tooth movement can then be compared with "in vivo" measurements of the orthodontic tooth movement. In this study, a specially developed hybrid retraction spring is employed. This spring enables the application of a defined, almost constant force system. The "in vivo" determined tooth movement is simulated with the aid of special positioning and measuring devices. Meanwhile, the active force system can be determined by 6-component force/moment sensors. The experimentally measured force system, "in vivo" measurements of tooth movement and the CT model are now available for numerical simulation for the first time.

Bone Remodeling↗