Knee bioelectric impedance assessment in healthy/with osteoarthritis subjects.

The present study analyzes parameters estimated by bioelectric impedance spectroscopy (BIS) in subjects with healthy and with osteoarthritis (OA) knees. Thirty-two male volunteers, members of the Parachute Military Infantry Brigade of Rio de Janeiro, Brazil, participated in the study (62 knee joints). Clinical specialists used the Dejour scale for OA classification and divided the subjects into a control (without OA) and a pathological group (with different degrees of OA). BIS data were obtained in a standing position using a BIS technique based on the current response to a step voltage excitation. Differences between groups were measured by means of a Wilcoxon-Mann-Whitney test. Results indicate that raw bioimpedance parameters seem to be sensitive to the physiological changes associated with OA. Thus, data indicate that extra-cellular resistance (Re) and reactance of the equivalent capacitance (Xcx) increase according to the disease intensity (p < 0.001). In conclusion, the BIS technique seems to be able to provide the objective and non-invasive basis for helping the diagnosis of knee OA.

Assessment of characteristic of the vasomotor control dynamics based on plethysmographic blood flow measurement.

Enhancing the knowledge about the characteristic of the vasomotor control can help physicians to improve the treatment of cardiovascular diseases and their consequences in people's daily activities. Vessels are generally evaluated from a static point of view, where some vascular features are obtained in a given space of time, or expressed as an average of some evaluation. The present study presents a method to assess some characteristics of the vasomotor control dynamics. Such a method is based on a mathematical description of the temporal profile of the blood flow observed during a reactive hyperemia condition induced by a protocol of 5 min of ischemia. The parameters for such a mathematical descriptive function were evaluated by searching for sensitivity to identify normal and vasomotor alterations induced by oral administration of ibuprofen (1200 mg) in ten healthy volunteers. The results indicated by the proposed mathematical description fitted appropriately experimental blood flow data (fitting-error of 0.18 ml/100 ml of tissue/min). Additionally, one parameter of the mentioned function was statistically different (P < 0.05) when one considers the normal and altered conditions of the vessel, even when the traditional peak and the basal flow values did not hint at the distinction.