Biomedical subjects

B S Strates

Publications and source records attributed to B S Strates.

At least 19 recordsLinked to original sources

PubMed1991

Healing of a large nonossifying fibroma after grafting with bone matrix and marrow. A case report.

Healing of a large tibial nonossifying fibroma in a 12-year-old girl occurred following excision, curettage, and filling of the bony defect with human demineralized bone matrix powder mixed with a small quantity of the patient's bone marrow. The use of this graft composite was successful in the treatment of the lesion and reduced the potential risk and morbidity associated with pediatric orthopedic surgical procedures with autogeneic iliac crest and other bone grafts.

Bone Marrow Transplantation↗

PubMed1991

Treatment of nonunion by percutaneous injection of bone marrow and demineralized bone matrix. An experimental study in dogs.

Successful treatment of nonunited fractures remains a major clinical challenge. Because bone marrow and demineralized bone matrix (DBM) are capable of stimulating osteogenesis, experiments were designed to test the effectiveness of bone marrow or DBM or both when injected percutaneously into a canine nonunion model. Six-millimeter segmental defects were created in the midtibial diaphysis of 24 adult mongrel dogs and held distracted by external fixation. For comparative purposes, a 0.5-mm osteotomy was created in five dogs. Five weeks later, the 6-mm defects were injected with either saline, autogeneic marrow, DBM powder, a composite of bone marrow and DBM, or treated by open grafting techniques with autogenic cancellous bone. Healing of the defect was evaluated roentgenographically, biomechanically (three-point bending), histologically, and biochemically 13 weeks postsurgery. Marrow and DBM stimulated defect healing. However, the combination of bone marrow with DBM produced a synergistic response in the defect, which was greater than the sum of either marrow or DBM alone. Healing in the composite-grafted dogs was comparable to those treated by standard cancellous bone grafting. These data suggest that percutaneous injection of bone marrow and DBM may be a potential alternative that offers numerous advantages over standard open grafting techniques in the treatment of fractures with nonunited defects.

Animals↗

PubMed1990

Quantitative roentgenographic densitometry for assessing fracture healing.

A noninvasive method was developed to assess fracture healing using optical densitometric methodology. Photometric measurements of osseous tissue density were based on illuminance or intensity of light, transmitted through standard roentgenograms. The method was tested in 6-mm tibial segmental defects and single-cut osteotomy defects in adult mongrel dogs. The lowest measureable bone density in the defect was compared to bending rigidity of the involved extremity. For both types of defect, an exponential relationship was found between the densitometric evaluation of the healing fracture gap and bending rigidity. This method proved superior to a roentgenographic scoring method and is capable of detecting small differences in mineral content using standard roentgenograms. The high correlation between densitometric evaluation and bone rigidity indicates this method has potential for use in the in vivo assessment of fracture healing.

Absorptiometry, Photon↗

PubMed1989

Osteogenesis in cranial defects and diffusion chambers. Comparison in rabbits of bone matrix, marrow, and collagen implants.

In rabbits, we compared calcification and bone formation by bone marrow, acid-demineralized bone matrix and glutaraldehyde-cross-linked Type I collagen implanted in intramuscular diffusion chambers or in trephine skull defects. The rabbits were killed 4 weeks postimplantation and calcification and osteogenesis were evaluated radiographically and histologically, and by calcium and alkaline phosphatase assays. Bone marrow produced bone and fibrous tissue within the chambers and had high alkaline phosphatase levels. Bone matrix in chambers with intact filters failed to induce bone formation within and outside the chambers, while glutaraldehyde-cross-linked collagen produced only scant calcific deposits following implantation in either diffusion chambers or skull defects. Central areas of skull defects implanted with bone marrow were partially repaired with new bone and had high calcium and alkaline phosphatase levels, but not as high as defects implanted with demineralized bone matrix.

Animals↗

PubMed1988

Biochemical differences between dystrophic calcification of cross-linked collagen implants and mineralization during bone induction.

Ectopic calcification of diseased tissues or around prosthetic implants can lead to serious disability. Therefore, calcification of implants of glutaraldehyde-cross-linked collagenous tissues and reconstituted collagen was compared with mineralization induced by demineralized bone matrix (DBM). Whereas implants of DBM accumulated large amounts of calcium and a bone-specific gamma-carboxyglutamic acid protein (BGP or osteocalcin) following implantation in both young and older rats, implants of cross-linked pericardium calcified with only traces of BGP. Glutaraldehyde-cross-linked DBM failed to calcify after implantation in 8-month-old rats for 2-16 weeks. Implants of cross-linked type I collagen exhibited small calcific deposits 2 weeks postimplantation but calcium content eventually dropped to levels equal to those of soft tissues as the implants were resorbed. The calcium content of DBM implanted in 1- and 8-month-old rats reached comparable levels after 4 weeks, but the BGP content was approximately twice as high in the younger animals than in the older ones. Glutaraldehyde-cross-linked implants of DBM, tendon, and cartilage calcified significantly in young but not in old animals. This form of dystrophic calcification was associated with only trace amounts of BGP. Alkaline phosphatase activity was high in implants of DBM and undetectable in implants of cross-linked collagenous tissues. These results show that implants of glutaraldehyde-cross-linked collagenous tissues and reconstituted collagen calcify to different extents depending upon their origin and the age of the host, and that the mechanism of dystrophic calcification differs significantly from the process of mineralization associated with bone induction as reflected by alkaline phosphatase activity and BGP accumulation.

Alkaline Phosphatase↗

PubMed1988

Skeletal repair in the aged: a preliminary study in rabbits.

Bone mass loss associated with aging can lead to osteoporosis and multiple bone fractures with impaired healing requiring prolonged hospitalization and costly medical care. We have used an experimental implantation model to test the ability of old animals to form new bone. Bone repair inducers, consisting of demineralized bone matrix (DBM), bone marrow, and collagen, were implanted in the abdominal wall muscles of 1-month and 16-month old rabbits. DBM contains a bone morphogenetic protein (BMP) that induces the differentiation of primitive mesenchymal cells into bone producing cells. The stromal cells of bone marrow can differentiate into osteoblasts after implantation, while collagen could serve as a calcification nucleus or framework for new tissue formation. Animals were killed 4 to 6 weeks after implantation. Implants were X-rayed, examined histologically, and analyzed for water content, calcium, and alkaline phosphatase. Only the implants of bone marrow enclosed in filter chambers (0.45 micron pore diameter) were associated with bone formation. Intramuscular implants of DBM and bone marrow in the old animals induced the formation of new bone but contained less calcium and lower levels of alkaline phosphatase than implants in the young animals. Collagen implants were resorbed and failed to induce bone formation or calcify. The results indicate that formation of new bone, under the conditions of this study, is reduced with aging.

Aging↗

PubMed1988

Ectopic bone formation is enhanced in senescent animals implanted with embryonic cells.

Ectopic bone formation induced by the subcutaneous implantation of demineralized bone matrix (DBM) is very significantly reduced in older Fischer 344 rats. Cells originating from calvaria of 20-day-old embryo donors were introduced into cylinders of DBM sealed at the ends with a Millipore filter or collagen sponges prior to subcutaneous implantation. Cells within the chambers had access to vascular channels that could penetrate through the interstices of the DBM. After four weeks of implantation in 26-month-old rats, the cylinders were full of bone. This bone was assessed by histologic techniques, by calcium and bone gamma-carboxyglutamic acid (gla) protein (BGP) concentrations, and by alkaline phosphatase activity. Cylinders to which no cells were added produced no bone. Bone marrow cells enclosed in similar cylinders or injected weekly at the implantation site also enhanced new bone formation but to a much lesser extent. Embryonic muscle cells formed large amounts of cartilage and less bone. Fibroblasts were inactive in this system. Prior treatment of the DBM with trypsin inhibited the myoblast response but not that of calvaria cells.

Aging↗

PubMed1987

A randomized study of two preparations for large bowel radiology.

A randomized study was carried out in 195 out-patients, due to undergo large bowel radiological examination, to compare the efficacy, patient acceptance and incidence of side-effects of a commercially-available bowel evacuant kit (magnesium citrate oral solution, phenolphthalein tablets and a bisacodyl suppository) and castor oil with enemas. Overall evaluation by a radiologist of large bowel preparation, based on post-barium evacuation X-rays, was satisfactory in more than 98% of patients while bowel cleanliness, as determined by the ability to detect a 1 cm lesion, was adequate in 95% of patients using either preparation. Patient acceptance was in favour of the commercial preparation in that fewer patients using it found the procedure uncomfortable or indicated a preference for another evacuant than did those prepared with castor oil and enemas.

Adult↗

PubMed1976