Ophthalmic manifestations of Rochalimaea species.

Rochalimaea henselae and R. quintana belong to the order Rickettsiales and are thought to be responsible for trench fever, bacillary angiomatosis, and cat scratch disease. We recently examined four patients with intraocular inflammation of unknown origin. Each patient had either unilateral or bilateral moderate loss of visual acuity ranging from 20/25 to counting fingers. Bilateral intraocular inflammation manifested by anterior and posterior segment cells, retinal lesions, macular exudate, and optic nerve head swelling was present to varying degrees. The R. henselae to R. quintana antibody titers were greater than or equal to 1:256 in each case. Marked improvement in vision occurred after treatment with either oral ciprofloxacin hydrochloride and prednisone or doxycycline hyclate. Rochalimaea species should be considered in the differential diagnosis of intraocular inflammation and inflammatory optic neuropathy. Appropriate treatment may result in marked improvement in visual acuity.

Anterior cruciate ligament allograft transplantation in dogs.

The biomechanical and clinical performance of bone-ligament-bone anterior cruciate ligament (ACL) allografts was studied in eight dogs. Allografts were collected from skeletally mature, healthy dogs using aseptic technique, and stored at -70 degrees for three to five weeks before implantation. The allografts were size-matched to the recipient dogs using ACL length and then rigidly fixed in position with interference screws and Kirschner wires. Three dogs regained a normal gait, and their grafts sustained breaking loads that were 25%, 41%, and 59% of controls. Partial or complete graft failure occurred in the other five dogs at some point in the study. Four had intraligamentous rupture and one had an avulsion fracture of the femoral attachment site. Joint-fluid cytology was normal in all eight dogs. Histologic examination showed persistent lymphoplasmacytic infiltrate. Eventually the allograft cores were incorporated in the host bed. Hyperplasia and fibrosis of the synovial membrane were diffuse and persisted as focal accumulations of mononuclear inflammatory cells.

Replacement of the anterior cruciate ligament. A comparison of autografts and allografts in dogs.

To compare the efficacy of allograft versus autograft replacement of the anterior cruciate ligament, 15 dogs had the ligament cut and replaced 1 month later: 11 dogs received a frozen bone-ligament-bone allograft cruciate ligament, while 4 dogs received a standard autogenous replacement with iliotibial band. Three of 11 allograft dogs developed postoperative infections and were removed from the study; and two of the remaining eight allograft ligaments were absent at autopsy. All the autograft ligaments were present. From serial clinical and radiographic examinations, there were no differences observed in the two groups. Autopsy studies at 4 months, however, showed an increased inflammatory, pannus-like reaction about the origins and insertions of the six allograft ligaments as compared with the four autografts. The ligament hydroxyproline uptake was lower in the allograft group, averaging 60 percent of the contralateral unoperated on control versus equal to the control in the autograft group. The tensile strength of the allografts reached only 17 percent of the control value versus 41 percent for the autografts. Lymphocytotoxicity testing at 1 month revealed a donor-specific antibody response in 4 of 8 allograft dogs; however, no histologic evidence of immune response was observed in the ligaments. The synovial fluid leukocyte count was elevated in the allograft group at 4 months. The increased synovial leukocyte counts and joint cartilage erosion, the decreased strength and metabolic activity of the grafts, and the evidence of an immune response in the allograft dogs do not support implantation of cadaver cruciate ligaments clinically at this time.

Effects of bone ingrowth on the strength and non-invasive assessment of a coralline hydroxyapatite material.

The dependence of strength on the amount of bone growth into a hydroxyapatite material made from coral was investigated. Block and granular forms of the material were implanted into cortical and trabecular regions of the skeletons of 16 dogs. The results were examined after 4, 8, 12 and 16 wk, with four dogs in each experimental group. When implanted into cortical bone, the bending strength of the implant material was found to be highly correlated with the amount of pore space which had become occupied by bone (r = 0.92, P less than 0.005 for the block form; r = 0.84, P less than 0.005 for the granular form). Multiple regression analysis showed that six histomorphometric measures of ingrowth accounted for 96% of the variability in bending strength of the block material, and there were no significant differences between block and granular forms of the material. On the other hand, when implanted into trabecular bone, the block form of the material achieved greater compressive strength than the granular form. While both strength and ingrowth increased with time, there were poor correlations between these two variables. Finally, when the material is implanted into trabecular bone, it becomes stronger in compression than the surrounding bone; when implanted in cortical bone, linear modelling suggests that resorption and replacement of the implant would be required to approximate the bending strength of the surrounding bone.

Mode of inheritance of Perthes' disease in Manchester terriers.

A test mating between two Manchester Terriers affected by Perthes' disease (PD) resulted in the birth of three affected males and two unaffected females. In the three puppies with PD, roentgenographically detectable changes in the affected femurs were observed two to three weeks before the onset of lameness and muscle atrophy in the corresponding limb. Analysis of the related pedigrees and of the results of the test mating indicated that PD is an inherited condition with high heritability.

Cement coating of osteoarticular allografts in rats to prevent the immune response.

Recently, more attention is being paid to the treatment of the articular surface defect in the young, active individual. Resurfacing or "shell" allografts are being considered as one of the alternatives for treatment. The immune response by the host may be the chief obstacle to the successful use of fresh osteoarticular allografts. Since proteins on the surfaces of allograft bone cells are considered to be the principal antigens eliciting the immune response, we hypothesized that mechanical masking of these cells by a biodegradeable blocking agent might prevent the immune response. Osteoarticular allografts of the distal femur were performed in rats and the cut surfaces of the graft were coated with cement before implantation. In a preliminary experiment, six biodegradeable cement materials were tried (bone wax, zinc polycarboxylate, collodion, fibrin adhesive, zinc oxide, and isobutyl-cyanoacrylate). Of these, the zinc oxide cement and isobutyl-cyanoacrylate were effective in inhibiting the immune response observed in control rat distal femur allografts. A second experiment was performed using nine rats with zinc oxide and nine rats with isobutyl-cyanoacrylate cements. These were compared with 20 control rats that had allografts without cement coating. Eighteen of the control rats (90%) developed an immune response, while only 22% (2/9) of the rats with zinc oxide coating and 33% (3/9) of the rats with isobutylcyanoacrylate developed an immune response. In a third experiment distal femur allografts were performed in 13 rats using only the liquid component of the zinc oxide cement.(ABSTRACT TRUNCATED AT 250 WORDS)