Digital Joint Reconstruction with Osteotendinous Joint Allograft: Experimental Study in Rats.

BACKGROUND: Fresh or frozen nonvascularized osteotendinous joint allografts (OTJA) have not been used previously, clinically or experimentally, for metacarpophalangeal joint reconstruction. Therefore, we evaluated the viability of OTJA for metatarsophalangeal joint (MTJ) reconstruction in rats. METHODS: In the experimental group of 12 Lewis rats, we reconstructed the MTJ of the third digit of the hindlimb with a fresh, nonvascularized OTJA obtained from the same digit from 12 donor rats. In the control group of 6 Lewis rats, an autologous composite osteotendinous graft of the MTJ of the same digit was obtained and repositioned in situ as an auto-transplant. Weight, pain, edema, dehiscence, and wound infection were evaluated every 24 hours for 30 days postoperatively. At the end of 30 days, we evaluated digit position, flexion and extension, passive mobility, radiological bone healing, and histological grades of rejection. RESULTS: We found no statistically different changes in weight, edema, pain, digit position, or radiological bone healing in either group. No wound dehiscence or infection was seen in any of the rats. Ten degrees of flexion and extension mobility were lost in the control group; the experimental group lost up to 30 degrees (P = 0.009). Histologically, 9 of the experimental group rats (9/12, 75%) showed rejection reactions compared with none of the controls (0%) (P = 0.009). CONCLUSIONS: Fresh nonvascularized OTJA caused an immune reaction without exposure of the graft, but with bone resorption. However, the rats maintained digital form and alignment with decreased passive flexion and extension of 10-30 degrees.

The antigen-antibody reaction in immunohistochemistry.

The problems of major concern in immunohistochemical practice are discussed in the following order: (a) the mechanism of the Ag-Ab reaction in fixed tissue as opposed to the in vitro reaction; (b) the chemistry of fixation and its influence on the final result of the immunohistochemical reaction; (c) the various procedures used for antigen retrieval in formaldehyde-fixed tissue; and (d) the consideration of the possible mechanism underlying heat-induced antigen retrieval. Suggestions for further work to attempt a clarification of the mechanism involved in the Ag-Ab reaction in immunohistochemistry resorting to existing histochemical methods for the demonstration of protein side groups are presented, together with some examples already published.

Síndrome de inmunodeficiencia adquirida (SIDA): una nueva entidad clínica / Acquired immunedeficiency syndrome (AIDS): a new clinical entity

En la primavera de 1980, se observaron en los Estados Unidos de Norteamérica los primeros casos de Síndrome de Inmuno-Deficiencia Adquirida (SIDA). Posteriormente han aparecido numerosas publicaciones en la Literatura Médica Mundial y en la Prensa Internacional. La observación clinica e inmunológica de laboratorio han hecho pensar en una etiología viral de esta enfermedad, sobre todo porque afecta los mismos grupos de alto riesgo de contraer Hepatitis B (homosexuales, drogadictos y pacientes que requieren uso continuo de hemoderivados)