Biomedical Engineering: Applications, Basis and Communications

We have recently demonstrated that a collagen sponge incorporating TGF-β1 was effective in inducing bone repair at the skull defect of rabbits. In this study, the bone repairing of rabbit skulls was tried by TGF-β1-incorporated collagen sponges of different thickness to assess the influence of the size of osteoinductive materials on the bone repairing.

The collagen sponge used was prepared by foaming and freeze-drying 1 % aqueous solution of pepsin-processed porcine atelo-collagen, followed by dehydrothermal crosslinking for 6 hr in vacua. Collagen sponges with different thickness were prepared by changing the volume of collagen solution for freeze-drying and changing the number of sponges piled up. An aqueous solution of TGF-β1 or ¹²⁵I-labeled TGF-β1 was dropped onto the freeze-dried sponge to prepare collagen sponges incorporating TGF-β1 or ¹²⁵I-TGF-β1, respectively. Collagen sponges were also radioiodinated with Bolton Hunter Reagent. Following implantation of the collagen sponges incorporating ¹²⁵I-TGF-β1 and the ¹²⁵I-labeled collagen sponges into the mice subcutis, each radioactivity remaining was measured to compare the time profile of in vivo retention of TGF-β1 with that of the sponge. The TGF-β1 incorporated collagen sponges of different thickness were implanted into full-thickness defects of rabbit skulls with 6 mm in diameter. The bone repairing at the defect was evaluated in terms of histological and DEXA examinations 6 weeks later.

The remaining radioactivity of ¹²⁵I-labeled collagen sponges and ¹²⁵I-labeled TGF-β1 incorporated in collagen sponges decreased with time. The remaining periods of radioactivities of the sponges prolonged with an increase in the sponge thickness, but those of TGF-β1 were independent with the sponge thickness. The collagen sponge with 2 mm thickness was the most effective in increasing the bone mineral density at the bone defect. This finding indicated that the sponge thickness is one of the key factors contributing to successful bone repairing.

A new pulse spectrum method of assessing autonomic function was examined in a pharmacological experiment on eight healthy volunteers. The pulse pressure data is obtained under control condition and in parasympathetic blocked by atropine. Compared with the spectral method of heart rate variability (HRV), which is wide-spreading in laboratory studies and clinical diagnosis nowadays, the method of pulsation spectrum provides a new and direct view to assess parasympathetic control. As can be seen from the results, the high frequency of pulsation harmonics are reduced by the parasympathetic blocked, and on the contrary, low frequency component increased. By the analysis of linear regression, the pulsation spectrum method indicates more correlations with atropine doses. We anticipate that the non-invasive assessment of short-term autonomic function will come to be performed more reliably and conveniently by using this method.

Gesture recognition is needed for a variety of applications. One particular application of gesture-based systems is to implement a speaking aid for the deaf. Among several factors constituting a hand gesture, the arm movement pattern is one of the most challenging features to recognize. In this paper, we propose a neural-network-based approach to recognition of spatio-temporal patterns of nonlinear 3D arm movements. Compared to Hidden-Markov-Model-based methods, the most appealing property of the proposed method is its simplicity. The effectiveness of this method is evaluated by a database consisted of 10 persons.

Treatment for bone deformities secondary to malunited fractures usually require corrective osteotomies, and high incidence of surgical failure rates have been reported. Inaccurate corrections and loss of reductions are among the most common causes, and these technical errors ought to be improved[1-2]. A new measuring fixator for humeral supracondylar corrective osteotomies in children was designed and used in clinical application. Several surgical trials were performed in vitro using rapid prototype models to simulate different bony deformities. Two boys who had sustained cubitus varus following malunited humeral supracondylar fracture were performed using proposed measuring fixator. The results of the clinical trial show that the angle of correction was accurate, and the procedure could be carried out by the surgeon himself without additional help, with an average of 1.3 penetration of the physis per each fixating Kirschner wire (8 times in 6 K-wires). The surgical time was reduced, as well as the radiation exposure.

Osteoarthritis (OA) encompassed a large and heterogeneous number of disorders affecting joints and bones, which culminate in a joint failure. In general, OA can be defined as a degenerative disease characterized by biomechanical and architectural deteriorations of the articular cartilage. After the age of 60 years, more than 80% of the people have radiological signs of OA in the knee, and 20% of the people suffer from pain and movement limitations. Currently used pharmacologic treatments, including acetaminophen and nonsteroidal anti-inflammatory drugs, do not slow or reverse the degenerative process in osteoarthritis. Glucosamine, a chondro-protective substance, has recently received a great deal of attention from the public as a potential treatment of osteoarthritis, prompting healthcare professionals to investigate its clinical usefulness and potential for adverse effects. Improvement in the symptoms of osteoarthritis associated with the use of glucosamine has been observed in clinical trials. The purpose of this study was to better define the efficacy of these chondro-protective agents in treating OA. The short term and long term results were evaluated with pain score, and the most importantly, we proposed to objectively evaluate the muscle strength, and the joint motion with gait and sit-to-stand analysis. These data will warrant a better understanding of the efficacy of these chondro-protective agents in treating osteoarthritic patients.

In this paper, a new compression scheme called hybrid compression model (HCM) is proposed for compressing clusters of similar images. The HCM exploits region growing to segment the median image that created by a cluster of similar images; and further, it uses centroid method to predict the values of original images data. The difference between the predict values and original data is stored for later use of progressive transmission. The experimental results obtained on various images show that our method provides significant improvement in compression efficiency while compared to the traditional centroid method.