Chemosterilized autolyzed antigen-extracted allogeneic (AAA) bone matrix gelatin for repair of defects from excision of benign bone tumors: a preliminary report

In a series of 33 bone graft operations, antigen-extracted, autolyzed, allogeneic (AAA) bone matrix gelatin was substituted for autologous bone. The period of follow-up was 2.0 to 3.5 years. AAA bone gelatin was resorbed more rapidly than whole bone. AAA bone gelatin was replaced by new bone in the same intervals of time as observed with autologous bone. In treatment of bone tumors with AA bone gelatin, the results of the operation depend upon the nature of the pathologic processes in the host bed. In normal host bed, tight contact between implant and recipient bone is essential for success. The overall results of a preliminary study of 33 cases of 91% successful.

Matrix-induced endochondral bone differentiation: influence of hypophysectomy, growth hormone, and thyroid-stimulating hormone

The influence of hypophysectomy (hypox), GH, and TSH on the discrete phases of matrix-induced endochondral bone differentiation was investigated. [3H]Thymidine incorporation by proliferating mesenchymal cells on day 3 was inhibited by hypox, but was corrected by GH administration. On day 7, 35SO4 incorporation into cartilage proteoglycans was reduced by hypox, but was restored to values higher than controls by GH. Calcification of cartilage and bone was monitored by alkaline phosphatase activity. 45Ca incorporation into bone mineral, and total calcium. Alkaline phosphatase levels were maximal on day 11 in the controls and declined thereafter; however, the activity of alkaline phosphatase remained elevated in hypox recipients. Hypox reduced and delayed the rate and extent of calcification, as reflected by 45Ca incorporation and total calcium, respectively. The administration of GH and TSH alone and in combination restored 45Ca incorporation to control values in tibial metaphyses but not in the matrix-induced osteogenic plaques on day 10. These findings imply that the hormonal requirements for initiation of de novo mineralization of bone may be different from those required for the maintenance of mineralization that was initiated in early fetal life, as in the case of metaphyses. Hypox resulted in a delayed and reduced bone formation due to 1) inhibition of mesenchymal cell proliferation, 2) decreased and delayed chondrogenesis, 3) delayed and reduced vascular invasion, and 4) impaired bone formation.

Hemopoiesis in demineralized bone allografts

Demineralized allogeneic bone matrix (DBM), implanted in muscle, induces the formation of an ossicle within which histologically recognizable hemopoietic tissue develops. Analyses of rabbit ossicle marrow in a methylcellulose culture system demonstrated the presence of committed hemopoietic precursors; colony-forming units in culture (CFUC), erythroid colony-forming units (CFUE) and erythroid burst-forming units (BFUE) by six weeks post-implantation. The time courses of colony and burst formation by progenitor cells of ossicle and femoral marrow were similar. Induction of hemolytic anemia by phenylhydrazine hydrochloride at six weeks post-DBM implantation showed that the ossicle marrow was responsive to systemic erythropoietic stimuli. The DBM implant may provide a unique model for studying the development of hemopoietic microenvironments within bone.

Detection of collagen degradation products from subcutaneously implanted organic bone matrix

Demineralized bovine bone powder was reduced with NaB3H4 to label the collagen crosslinks with tritium. The powder was enclosed in small nylon mesh pouches and implanted subcutaneously into rats for 3 weeks. Histological examinations revealed that multinuclear giant cells accumulated around the bone matrix, some in Howship's lacunae. Collagenous peptides containing intermolecular crosslinks were detected in the urea-soluble fraction extracted from the implant. Two crosslink-containing peptides were isolated from a dialyzable fraction: one contained dihydroxylysinonorleucine and the other hydroxylysinonorleucine. Both peptides had molecular weights of approximately 1000 estimated from the elution positions of gel filtration chromatography; and both had similar quantitative compositions of amino acids. There were no homologous peptides detected in a control experiment of the reduced bone matrix which was incubated in vitro with buffered saline for 1 week at 37 degrees C.

Degradation of bone matrix morphogenetic activity by pulverization

The yield of new bone from implants of pulverized demineralized whole matrix and bone matrix gelatin declines as the particle size decreases in diameter below 125 microns. The corresponding increase in surface area and mechanically-induced free radicals is associated with an increase in solubility of bone matrix proteins. These changes in physiocochemical properties and the concomitant reduction in bone yield suggest that prolonged pulverization denatures a bone morphogenetic protein (BMP).

The bone inductive capacity of various bone transplanting materials used for treatment of experimental bone defects

The bone defect repairing capacities of autogenous cancellous bone (ACB), decalcified bone (DB), autodigested "low-antigenic" bone matrix (LBM) and preserved bone (PB) were tested in experimental defects in rabbit scapulae. The healing of the defects was most effective with ACB transplants as judged by roentgenologic and microscopic studies. The DB and LBM transplants caused states of healing comparable to each other, and the PB transplants showed the least satisfactory results in this experiment. The ACB, DB and LBM transplants caused bone induction, which resulted in the formation of new bone, subsequent resorption of the transplanted material and rapid reshaping of the callus. The PB transplants caused no bone induction; only some growth of callus on the edges of the defect was observed and pieces of the transplanted material were seen as late as 10 weeks after the operation as dead particles encapsulated by fibrous tissue. The infiltrations of inflammatory cells around the PB transplants indicated a considerable host versus graft reaction whereas this reaction was less with the other materials tested.

Matrix formation in the mandibular condyle of the rat (35S) - sulfate incorporation studies

The matrix formation activity of the mandibular condylar cartilage was investigated using radioactive sulfate incorporation. The condylar cartilage was studied at various developmental stages; as an autotransplant, in situ and on a chemically defined medium. An initial decrease in the cpm/DNA was followed by an increase, until a maximum was attained for all groups, between the 14th and 17th days. Thereafter, the matrix formation activity decreased. There was a surprising likeness in the patterns of activity for all the samples investigated. This tends to support the hypothesis that cartilagenous growth seem to be regulated, at least to some extent by one or more humoral factors.

The effects of zinc deprivation on the host response to intramuscular bone matrix implants in the rat

Sterile sequentially extracted insoluble bone matrix gelatin and freeze-dried allogeneic demineralized whole bone matrix was implanted into a lumbar muscle pouch of 12 Sprague-Dawley rats fed a diet containing 0.9 ppm zinc and into 6 rats fed a diet containing 50 ppm zinc. Histological sections and microradiography demonstrated that skeletal tissue induction occurred in all instances. In the zinc-supplemented hosts, four weeks postimplantation, trabecular bone and bone marrow grew on both sides of the matrix implant which had been almost completely resorbed by matrixclast activity. However, in the zinc-deficient hosts, the central cavity of the matrix was first filled with mesenchyme and then cartilage cells which grew in the form of thin wedges into the implanted matrix. Poor vascularization appears to be an important factor in cell proliferation and abnormal differentiation in zinc deficiency.

[Spontaneous fractures and tumors (author's transl)]

During childhood, pathologic fractures are found in systemic diseases of the skeleton (e.g. osteogenesis imperfecta or rachitis), but especially when bone tumors or tumorlike changes are present. Conservative measures such as continuous traction and application of a plaster cast lead to healing of the fracture only in a limited number of cases. Treatment of benign and potentially malignant and tumors and of tumorlike growths by excochleation and by resection and subsequent filling of the defect with autologous spongiosa and in some cases metallic fixation respectively has proved useful. The surgical treatment of malignant tumors depends on the king of tumor and its localization.

Collagenous bone matrix-induced endochondral ossification hemopoiesis

Transplantation of collagenous matrix from the rat diaphyseal bone to subcutaneous sites resulted in new bone formation by an endochondral sequence. Functional bone marrow develops within the newly formed ossicle. On day 1, the implanted matrix was a discrete conglomerate with fibrin clot and polymorphonuclear leukocytes. By day 3, the leukocytes disappeared, and this event was followed by migration and close apposition of fibroblast cell surface to the collagenous matrix. This initial matrix-membrane interaction culminated in differentiation of fibroblasts to chondroblasts and osteoblasts. The calcification of the hypertrophied chondrocytes and new bone formation were correlated with increased alkaline phosphatase activity and 45Ca incorporation. The ingrowth of capillaries on day 9 resulted in chondrolysis and osteogenesis. Further remodelling of bony trabeculae by osteoclasts resulted in an ossicle of cancellous bone. This was followed by emergence of extravascular islands of hemocytoblasts and their differentiation into functional bone marrow with erythropoietic and granulopoietic elements and megakaryocytes in the ossicle. The onset and maintenance of erythropoiesis in the induced bone marrow were monitored by 59Fe incorporation into protein-bound heme. These findings imply a role for extracellular collagenous matrix in cell differentiation.

The matrix of rat calvarium as transformant of fibroblasts

Allogeneic transplantation of coarse powders of the rat calvarial matrix to subcutaneous spaces resulted in transformation of fibroblasts to chondroblasts and osteoblasts. The emergence of new phenotypes was quantitated by determination of alkaline phosphatase activity and 45Ca incorporation. A comparison of the matrices from rat calvarium and diaphyseal bone revealed that matrix of the shaft of long bones is more potent as transformant than matrix of the vault of the skull.

[Reaction of the bone- and soft tissues to implanted bone wax in the sheep]

2,5 gr. of bone wax (Knochenwachs) were implanted in the iliac crest of 10 sheep. The induction of a foreign body reaction and chronic inflammation was proven demonstrable until the 12th week after implantation of the bone wax. In this period only partial resorption of the wax occurred simultaneously with significantly retarded osseous regeneration. From a clinical point of view it therefore seems necessary when using bone wax to pay particular attention to inflammatory reactions, reduced new bone formation and eventual occurrence of pseudo-arthrosis.

Use of marrow-cancellous bone grafts in maxillary alveolar and palatal clefts

Autogenous particulate cancellous bone and marrow grafts were studied in bilateral, surgically produced palatal and alveolar clefts in six young rhesus monkeys. Fluorescence and routine light microscopy indicated complete osseous regeneration of the cleft areas. Tooth buds on either side of the surgical area were not disturbed by the grafting procedure.