This review discusses the factors important in the incorporation or integration of biomaterials and devices by tissue. Methods for surface modification and surface-sensitive techniques for analysis are cited. In vitro methods to evaluate the biocompatibility or efficacy of certain biomaterials and devices are presented. Present and future directions in neural prostheses, cardiovascular materials, blood or bone substitutes, controlled drug delivery, orthopedic prostheses, dental materials, artificial organs, plasma- and cytapheresis, and dialysis are discussed.

Tumoral calcinosis (TC) is a rare inherited autosomal dominant metabolic disease manifested by elevated serum phosphorus and 1,25 dihydroxyvitamin D levels and periarticular cystic and solid tumorous calcifications. The dental findings in a large family have been critical in determining the genetic transmission of the condition. Radiographically the teeth have short bulbous roots, pulp stones and partial obliteration of the pulp cavity. Histologically, coronal dentin and a variable amount of radicular dentin appears to be deposited regularly. At nonspecific points the developing radicular dentin appears to encounter a mass of calcified material and proceed to grow around it. This mass has a unique histologic pattern with ovoid spaces surrounded by amorphous calcification. At levels of further root development the radicular dentin has an irregular bending tubule arrangement. The dental lesion of TC appears to be different from that of radicular dentin dysplasia in histologic structure and in the method of initiation of the dentin defect. These data suggest that the specific dental lesion is a new phenotypic marker for TC.

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Neutrophils, especially in acute infection or the myeloid leukemias, may shed platelet-sized particles that can readily be distinguished from true platelets because they contain neutrophil myeloperoxidase. This enzyme, unlike platelet peroxidase, is not inhibited by glutaraldehyde. The myeloperoxidase and acid hydrolase levels and continuous plasma membranes of these cell-like particles suggest that they are functional cellular entities. They further differ from platelets in that they contain nuclear remnants, occur in bacteria-laden pus and inflammatory exudates, are ingested by macrophages, and do not adhere to each other or aggregate. They could be involved in the immune response to pathogens or contribute to trauma and healing by facilitating deployment of neutrophil acid hydrolase, neutral protease, and myeloperoxidase.

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