Measurement of Human Gait Symmetry using Body Surface Normals Extracted from Depth Maps

In this paper, we introduce an approach for measuring human gait symmetry where the input is a sequence of depth maps of subject walking on a treadmill. Body surface normals are used to describe 3D information of the walking subject in each frame. Two different schemes for embedding the temporal factor into a symmetry index are proposed. Experiments on the whole body, as well as the lower limbs, were also considered to assess the usefulness of upper body information in this task. The potential of our method was demonstrated with a dataset of 97,200 depth maps of nine different walking gaits. An ROC analysis for abnormal gait detection gave the best result ( AUC = 0.958 ) compared with other related studies. The experimental results provided by our method confirm the contribution of upper body in gait analysis as well as the reliability of approximating average gait symmetry index without explicitly considering individual gait cycles for asymmetry detection.

Human gait symmetry assessment using a depth camera and mirrors

It is proposed in this paper a reliable approach for human gait symmetry assessment using a Time-of-Flight (ToF) depth camera and two mirrors. The setup formed from these devices provides a sequence of 3D point clouds that is the input of our system. A cylindrical histogram is estimated for describing the posture in each point cloud. The sequence of such histograms is then separated into two sequences of sub-histograms representing two half-bodies. A cross-correlation technique is finally applied to provide values describing gait symmetry indices. The evaluation was performed on 9 different gait types to demonstrate the ability of our approach in assessing gait symmetry. A comparison between our system and related methods, that employ different input data types, is also provided.

Skeleton-Based Abnormal Gait Detection

Human gait analysis plays an important role in musculoskeletal disorder diagnosis. Detecting anomalies in human walking, such as shuffling gait, stiff leg or unsteady gait, can be difficult if the prior knowledge of such a gait pattern is not available. We propose an approach for detecting abnormal human gait based on a normal gait model. Instead of employing the color image, silhouette, or spatio-temporal volume, our model is created based on human joint positions (skeleton) in time series. We decompose each sequence of normal gait images into gait cycles. Each human instant posture is represented by a feature vector which describes relationships between pairs of bone joints located in the lower body. Such vectors are then converted into codewords using a clustering technique. The normal human gait model is created based on multiple sequences of codewords corresponding to different gait cycles. In the detection stage, a gait cycle with normality likelihood below a threshold, which is determined automatically in the training step, is assumed as an anomaly. The experimental results on both marker-based mocap data and Kinect skeleton show that our method is very promising in distinguishing normal and abnormal gaits with an overall accuracy of 90.12%.

Ultrasonography of a bone metastasis

The authors report a case of cortical bone metastasis presenting as a soft-tissue mass in the thigh. Because of the initial clinical presentation, ultrasonography was performed first; plain radiography and a percutaneous biopsy provided additional diagnostic information. The authors describe the ultrasonographic findings and the role of this imaging technique in the final diagnosis of such lesions.

Role of the Na+, K(+)-adenosine triphosphatase in the accumulation of cis-diamminedichloroplatinum(II) in human ovarian carcinoma cells

We examined the importance of the Na+, K(+)-ATPase in cisplatin (DDP) accumulation in 2008 human ovarian carcinoma cells and describe changes in the Na+, K(+)-ATPase in DDP-resistant cells with DDP accumulation defects. Approximately 50% of DDP accumulation was inhibitable by ouabain. DDP accumulation into 2008 cells could be maximally inhibited when cells were preincubated with ouabain for 1 h prior to DDP exposure. The half-maximal inhibition was obtained with 0.13 microM ouabain. Similar inhibition of DDP accumulation was obtained when the Na+, K(+)-ATPase was blocked by ATP depletion or by incubating cells in K(+)-free medium. This same percentage of DDP accumulation was Na+ dependent and varied directly with Na+ concentration. These effects on DDP accumulation could be detected as early as 1 min after the imposition of 0-trans conditions, strongly suggesting that the inhibition was due to modulation of a drug influx step. The Na+, K(+)-ATPase in 2008/DDP cells had a similar KD for ouabain binding and 36% less Na+, K(+)-ATPase molecules/mg of protein than 2008 cells. 2008/DDP cells 2.3 +/- 0.2 (SE, n = 3) fold cross-resistant to ouabain in a continuous exposure clonogenic assay. Despite these changes in the Na+, K(+)-ATPase, the net basal Na+, K(+)-ATPase activity was the same in sensitive and DDP-resistant cells as determined by ouabain-inhibitable 86Rb+ influx. The basal Na+ levels were also similar in the sensitive and resistant cells. These data suggest that DDP accumulation is partially Na+ dependent and that, therefore, the Na+, K(+)-ATPase which maintains the Na+ gradient may play an important role in determining how much DDP enters cells. Whether there is a causal link between the changes in the Na+, K+-ATPase in DDP-resistant cells and their DDP accumulation defect is not yet known.