The use of three-dimensional printing technology in orthopaedic surgery.

Three-dimensional (3-D) printing or additive manufacturing, an advanced technology that 3-D physical models are created, has been wildly applied in medical industries, including cardiothoracic surgery, cranio-maxillo-facial surgery and orthopaedic surgery. The physical models made by 3-D printing technology give surgeons a realistic impression of complex structures, allowing surgical planning and simulation before operations. In orthopaedic surgery, this technique is mainly applied in surgical planning especially revision and reconstructive surgeries, making patient-specific instruments or implants, and bone tissue engineering. This article reviews this technology and its application in orthopaedic surgery.

In vitro synthesis of humoral factors (immunoglobulins and complement) in lesional skin of leprosy patients

Reviews the leprosy situation in the world and in Suriname, as well as its clinical forms and immunological aspects. Skin samples with a diameter of 6 mm were taken from untreated lepers, 3 samples per patient. The aims were: to determine whether humoral factors are synthesized in the skin lesions of lepers, to study cells producing immunoglobulins and complement, and to study whether the locally synthesized immunoglobulins have antibody activity against M. leprae. The in vitro culture technique (Hochwald 1961/ Furth 1966), the direct immunofluorescence technique and the crossed immuno-electrophoresis with intermediate gel (Axelsen/Week;1973) were used. It was shown that lesional skin of indeterminate leprosy does not synthesize immunoglobulines. However, IgG was synthesized in tissue cultures of other leprosy varieties. Ig-positive cells were found in some of the patients examined, whereas complement-positive cells were not found. Culture fluid did contain newly synthesized antibodies against different M. leprae antigenic components. These antibodies were also found in the sera of the patients examined. This showed that antibody synthesis does not take place in the skin lesions, but elsewhere in the body. The biological significance of these antibodies is not yet known. Further study is needed to throw light upon this problem