Gamma irradiation of HIV-1.

The potential for transmission of human immunodeficiency virus (HIV) type 1 has created serious concern for the continued clinical use of bone and soft-tissue allografts. Tissue banks have employed 1.5-2.5 Mrad for sterilization of bone and tendon allografts, which, according to the current literature, approaches the level at which the tissue quality is adversely affected for implantation. Our working hypothesis was that gamma irradiation at increasing doses can proportionately inactivate HIV type 1. The objective of this study was to inactivate HIV type 1 by irradiation, as determined by its capacity to infect human T-lymphocytes and established cell lines in vitro. The replicative competence of HIV type 1 was also assessed by the presence of reverse transcriptase activity, enzyme-linked immunoadsorbent assay (ELISA), immunofluorescence assays for p24 viral core antigen, and the formation of syncytia induced by HIV type 1 in the cultures inoculated with irradiated virus. The results demonstrated the presence of active viral replication in previously noninfected cells in the supernatant samples that were exposed to as much as 5.0 Mrad. The data for the 10-Mrad sample were indeterminate due to cellular damage. These data suggest that gamma irradiation (1.5-2.5 Mrad) does not constitute a virucidal dose for HIV type 1. Current technologies for screening have greatly improved, and the surgeon should rely on tissue bank screening procedures and other methods of preparation rather than sterilization by gamma radiation techniques in choosing allograft material.

An anatomical basis for the degree of displacement of the distal chevron osteotomy in the treatment of hallux valgus.

The purpose of this study was to define the amount of lateral displacement of the chevron osteotomy to obtain a 50% displacement of the capital fragment. While mathematical analyses exist to predict the degree of correction of the intermetartarsal 1-2 angle with a distal metatarsal osteotomy, no guidelines exist regarding the degree of displacement (translation) that allows sufficient bone contact to enhance union and maintain stability of the osteotomy. We have addressed this concern based on anatomical parameters. The mean metatarsal width of the male specimens measured at 15 mm from the medial osteochondral junction was 15.3 mm (range, 13-18 mm; standard deviation, 1.6). The mean width among the female specimens was 14.5 mm (range, 11-18 mm; standard deviation, 1.6). This difference was statistically significant (P = 0.003). From the results of this study, we have concluded that when using a distal metatarsal osteotomy of the chevron type, in 97.5% of the cases the distal fragment can be translated laterally 6.0 mm in males and 5.0 mm in females to displace it 50% of its diameter.

A case of germinal center formation by CD45RO T and CD20 B lymphocytes in rheumatoid arthritic subchondral bone: proposal for a two-compartment model of immune-mediated disease with implications for immunotherapeutic strategies.

In rheumatoid arthritis (RA) disease activity occurring as joint destruction of cartilage and bone is thought to be driven by inflammatory reactions which are initiated by exogenous microbial mechanisms and perpetuated by endogenous autoimmune mechanisms. According to the synovial model of RA, these reactions originate in the adjacent synovial tissues. The following set of observations is presented herein to suggest an alternate model involving subchondral bone. Lymphocytic infiltrates accompanied by immunoglobulin deposits were identified in rheumatoid subchondral bone near areas of cartilage undergoing destruction by local subchondral inflammation. CD45RO T lymphocytes also were identified with these infiltrates as well as with CD20 B lymphocytes in an area of subchondral bone containing a well-organized germinal center. Analysis of extracts of rheumatoid subchondral bone revealed a high incidence of autoantibodies directed against type II collagen, the major protein constituent of cartilaginous tissue. Analysis of IgG subclass and cyanogen bromide peptide specificity revealed a pathogenic subset of these autoantibodies. A passive transfer study utilizing similar antibodies from collagen arthritic animals confirmed that such autoantibodies would have the potential of contributing directly to disease activity observed in rheumatoid subchondral bone. These studies suggest that (i) subchondral bone may be playing an active role in RA as a local site of immune-mediated disease activity and (ii) basic and therapeutic studies aimed at understanding and eventually controlling RA should be diversified to include the study of not only synovial tissue, but also subchondral bone as a local source of the antigenic, cellular, and humoral immune components of joint destruction.

Comparison of antibiotic release from polymethylmethacrylate beads and sponge collagen.

The rates of elution of tobramycin in vitro were compared for polymethylmethacrylate beads impregnated with the powder form and an alternative biodegradable substance, sponge collagen. The impregnated polymethylmethacrylate beads initially had a lower zone of inhibition, but the rate of release was slow in comparison with that of the impregnated sponge collagen. The sponge collagen delivered a higher dose faster and with a shorter duration than the polymethylmethacrylate beads with the same antibiotic concentration in vitro, but the beads delivered a therapeutic concentration for longer periods. Because it deteriorates rapidly, sponge collagen may be unsatisfactory as an agent of antibiotic delivery in patients who have chronic osteomyelitis; however, it may be useful for patients who have acute trauma with highly contaminated bone or soft tissue, or during hemiarthroplasty revision, to deliver a high local concentration of antibiotic for a short period of time.

Prediction of angular deformity and leg-length discrepancy after anterior cruciate ligament reconstruction in skeletally immature patients.

Injuries to the anterior cruciate ligament (ACL) in young children and adolescents are becoming more common as more youngsters participate in organized sports. The dilemma for the orthopaedic surgeon is that untreated ACL ruptures may result in meniscal damage and joint degeneration, whereas surgical treatment may result in physeal arrest, with shortening and angular deformity. To help determine the appropriate timing for ACL repair in skeletally immature patients, graphs have been developed to predict the amount of shortening and angular deformity to expect after repair.

Leg length discrepancy associated with vivid cutis marmorata.

Cutis marmorata telangiectatica congenita (CMTC), a rare benign condition usually present at birth, is characterized by areas of cutaneous marbling that often become more pronounced with low temperatures. The skin lesions typically become less prominent with age, but may be associated with a variety of abnormalities. Reported are three patients with vivid cutis marmorata who had leg length discrepancies (LLD) which, unlike most limb discrepancies caused by vascular malformations, involved relative growth retardation of the affected leg.

Effect of fetal thyroid hormone (RT3) on sarcoma cells in culture.

Fetal thyroid hormone (RT3) is considered metabolically inactive and is present in high concentration in fetuses and in some patients with end-stage malignant disease. In a virus-induced erythroleukemia cell model, RT3 was found to stimulate the growth of the erythroleukemia cells in culture. The focus of this research was to test the effect of RT3, at several concentrations, on the growth of naturally occurring human sarcomas in cell culture. Cloned cell lines of Ewing sarcoma, rhabdomyosarcoma, and osteogenic sarcoma were grown in multiple flasks of serum-free medium containing varying concentrations of RT3, ranging from 10(-8)-10(-5) M. Cells grown in serum-free medium containing no RT3 were used as a control. RT3 significantly increased the growth (total protein) of the rhabdomyosarcoma cell line in culture at concentrations between 10(-8) and 10(-6) M, with the maximum effect at 10(-7) M. The growth of one cell line of Ewing sarcoma was not affected by RT3 for any of the concentrations tested. The growth of two Ewing sarcomas and one osteogenic sarcoma was significantly stimulated by RT3 but only at the highest concentration of 10(-5) M. The growth of the other osteogenic sarcoma cell line was significantly increased at concentrations of 10(-6) and 10(-7) M. The stimulatory effect of RT3 on several sarcoma cell lines in culture suggests the presence of a specific receptor in the neoplastic cells and the possibility that RT3 may be useful as a model for new chemotherapeutic agents.

The Chevron bunionectomy: a trigonometric analysis to predict correction.

A trigonometric analysis was developed in an attempt to predict the postoperative hallux valgus angles and intermetatarsal angles after Chevron bunionectomy. This analysis was used in 20 feet to predict postoperative angles, and these predicted values were compared with actual measured roentgenographic values. The postoperative intermetatarsal angles were evaluated to determine their correction to postoperative hallux valgus angles of 20 degrees or less. Using the trigonometric analysis, the postoperative intermetatarsal angles were highly predictable, but the hallux valgus angle could not be reliably predicted for individual patients. The intermetatarsal angle obtained at surgery, however, was indicative of the final hallux valgus angle: 75% of feet with intermetatarsal angles of more than 11 degrees had postoperative hallux valgus angles of more than 20 degrees. Thus, when an intermetatarsal angle of 11 degrees or less can be obtained surgically, the hallux valgus angle can be corrected to 20 degrees or less in most patients.

Tissue distribution of 125I-labeled fetal thyroid hormone in nude mice xenografted with Ewing sarcoma.

Biodistribution of fetal thyroid hormone (RT3) was studied in nude mice with Ewing's sarcoma xenografts. At 30 min and 1, 2, 4, 8, and 12 hr after injection, blood, tumor and normal organs were measured to determine the amount of radioactivity per gram of tissue. The amount of radioactivity in the blood of tumor-bearing mice decreased sharply from 7.64% of injected dose per gram of tissue (% ID/g) at 30 min after inoculation to 0.45%/ID/g at 12 hr. The % of injected dose per gram for 125I-labeled RT3 in the tumor reached 1.92 at 1 hr after injection and decreased to 0.22 at 12 hr. The radiolocalization indices for tumor to other organs at 12 hr ranged from 1.35 to 4.43. This study suggests increased localization of RT3 in the Ewing's sarcoma as compared to other tissues in the nude mouse.

Neurologic complications after K-wire fixation of supracondylar humerus fractures in children.

A retrospective review of 143 supracondylar humerus fractures in children treated with K-wire fixation disclosed four neurologic complications after treatment. There were two late ulnar neuropraxias. One ulnar nerve injury and one radial nerve injury resulted from direct trauma during insertion of a K-wire. All patients regained full neurologic function.

Radiation exposure to patients receiving routine scoliosis radiography measured at depth in an anthropomorphic phantom.

Concern about the amount of radiation received during scoliosis evaluation and treatment led us to measure radiation exposure in an anthropomorphic phantom to determine the increased risk of breast cancer in young women with scoliosis. Assuming that 22 radiographic examinations were performed over the course of scoliosis treatment, the increased relative risk of breast cancer was determined to be 0.22% in these patients.