Equine demineralized bone matrix, particle size 2 to 4 mm, was implanted SC and IM in 4 foals and 4 adult horses. The implants were removed between 5 and 8 weeks after implantation. Bone formation was induced by SC and IM implantations in all animals. The implantation site had a marked effect on the amount of bone that developed, bone being formed earlier and in greater amounts when the matrix was implanted IM. The amount of bone formed increased with increasing time after matrix implantation at both sites. Demineralized bone matrix implantation also led to formation of small amounts of chondroid tissue; this tissue was more common in IM than SC matrix implants, and increased in amount with increasing time after implantation. Formation of this chondroid tissue did not precede the formation of bone, and there was no evidence that implantation of demineralized bone matrix in horses induced endochondral ossification. Age of the host did not appear to affect the response.

Microscopic examination of the nasal mucosa of clinically normal specific-pathogen-free pigs and of toxicogenic type-D Pasteurella multocida toxin challenge-exposed specific-pathogen-free pigs indicated that the surface epithelium in pigs of both groups was microscopically normal; erosions or appreciable inflammatory changes were not evident. In pigs of both groups and in aU 3 regions of the nasal cavity, the endothelial lining of all blood vessels appeared normal without detectable changes to the walls at postinoculation day 10. Vascular injury in the cartilage or the bone was not discernible in control or challenge-exposed pigs. There were marked differences in the osseous structures of the conchae when the 2 groups were compared. In control pigs, active bone formation and remodeling were observed, and the septal cartilage was normal. In toxin challenge-exposed pigs, there likewise was normal bone formation and remodeling in the vestibular region, and the septal cartilage was normal. In marked contrast, conspicuous changes were observed in the osseous core of the conchae of the respiratory and, sometimes, the olfactory regions. These changes consisted of bone necrosis and resorption by large numbers of osteoclasts with variable replacement by dense mesenchymal stroma, which resulted in conchal atrophy. In the absence of any discernible damage or injury (angiopathy) to the nasal vessels, it appears that the action of the dermonecrotoxin of P multocida serotype D is on the most active osteoblasts and the associated organic matrix of the bone, with subsequent disruption of normal bone formation and remodeling of the nasal conchae.

Cortical bone screws were implanted into the proximal portion of the right and left radius and ulna of 6 newborn Quarter Horse foals as radiographic markers for measurement of growth. Distance between markers on a lateral radiographic view was measured. Radiographs were taken at 2-week intervals until the horses were 8 weeks old, at 4-week intervals until they were 48 weeks old, and at 12-week intervals until they were 72 weeks old. The proximal radius and ulna grew at similar rates during the 72-week period of evaluation, and growth continued throughout 72 weeks. The proximal radius grew 3.5 cm, and the ulna grew 3.4 cm. Although the rates of growth were similar, growth from the ulnar physis contributed only to the length of the olecranon; growth was not transmitted to the ulnar diaphysis distal to the cubital joint. The proximal radius slid distally in relation to the ulna as growth occurred at the proximal radial physis. These findings suggest that transfixing the ulna to the radius while growth is occurring at the proximal radial physis impedes the natural shifting process, and subluxation of the elbow can result. Severity of subluxation would be inversely related to the age of the horse at the time of transfixation.

This study was undertaken to obtain basic data of the sternal development in Korean native cattle from the earliest sternal formation to the ossification using histological and histochemical methods. Thirty three sterna were collected from a series of embryos and fetuses ranging from 11 to 225mm (estimated age 37-120 days) in crown rump length. The bilateral sternal bars were observed in the 2nd group (CRL 21-30mm) of Korean cattle embryos. Those bars initiated to be fused in the 3rd group (CRL 31-40mm) and completed in the 7th group (CRL 71-80mm). The ossification centers were detected in the 8th group (CRL 81-90mm) also bilateral ossification centers were found in the same group. The typical epiphyseal plates, endochondral bone and calcium deposit were found in the 9th group (CRL 91-100mm). Osteocytes, osteoblasts, osteoclasts and myeloid cells appeared in ossification centers in the 10th group (more than CRL 101mm). The alcianophility responded markedly in the 9th group that was decreased and showed slightly positive reaction in territorial matrix of the 10th group. Marked positive reaction to PAS was observed in bony trabeculae in the 10th group. The positive reaction to calcium deposit by trichrome stain was observed initially in the hypertrophied zone of epiphyseal plate in the 9th group and was conspicuous in the calcified zone of epiphyseal plate in the 10th group. The 1st positive reaction to the von Kossa stain was observed in the 9th group.

Twenty-one dogs(male 11 heads, female 10 heads) which were about 16 months (16.3+_3.5) old and 10kg(10.1+_2.0) body weight, were allotted randomly into four groups as follows. Group I consisted of five dogs whose muscles were operated for sham muscle injuries. Group II consisted of seven dogs treated for cystic duct obstruction. Group III consisted of five dogs treated for the union fracture model. Group IV consisted of five dogs treated for the nonunion fracture model. Radiographical and histological observations were carried out to determine bone alkaline phosphatase(BALP) and total alkaline phosphatase(TALP) values of each group for 20 weeks after the treatments with the condition of new bone formation. And also the applicability of percentage of BALP values to TALP (B/T) was studied after BALP was compared respectively with TALP. The level of TALP was increased without any relation to bone formation in group II, and all levels of BALP and B/T were increased in group III. The mean of B/T was high in statistical significance, due to varied levels of B/T and BALP. The changes of rates of B/T were significantly increased only in the case of the active new bone formation in group III, union fracture model. It was recognized that the mean values of B/T were statistical significant of the high applicability of the B/T ratio as and index of bone formation.