Fibrin adhesive derived from snake venom in periodontal surgery: histologicalanalysis

BACKGROUND: A new fibrin adhesive made of buffalo plasma-derived fibrinogen and a thrombin-like snake venom enzyme, has been successfully used to immobilize free gingival grafts. This case series histologically compared sutured grafts (control group) with others immobilized by using the fibrin adhesive (experimental group). CASE DESCRIPTION: The grafts were placed in the contralateral mandibular bicuspids of 15 patients, so that each subject received one treatment of each type. Five biopsies of each group were collected at 7, 14 and 45 days of healing, which were histologically and morphometrically analyzed as regards the relative volume density of the different connective tissue components. RESULTS: The sites in the control group presented a higher inflammatory cell density at 7 days and a tendency towards a lower collagen density. In the experimental group, the grafts had an appearance of more advanced healing. Tissue maturity characteristics progressed until 14 and 45 days, but no difference between groups could be noted at these times. Conclusions: Within the limits of the present study, it may be suggested that the alternative fibrin adhesive tested could represent an alternative to sutures in gingival grafts procedures.

Bone regeneration after demineralized bone matrix and castor oil (Ricinus communis) polyurethane implantation

Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial.

Anomalías vasculares de partes blandas: imágenes diagnósticas / Vascular anomalies of soft tissues: diagnostic images

Vascular anomalies include different pathologies as hemangiomas and vascular malformations, however they usually are reported together and confusion is created. Mülliken and Glowacki proposed a classification posteriorly, modificated, adapted and actually in use. Unfortunately is not sufficiently known for our radiologist. Classification and imaging correlation of soft-tissue vascular anomalies are revised, since a exact diagnosis is a great value for appropriate treatment and prognosis.

Las anomalías vasculares han sido tradicionalmente tratadas en conjunto aun cuando engloban patologías tan diferentes como hemangiomas y malformaciones vasculares. La clasificación dada a conocer por Mülliken y Glowacki, modificada posteriormente, no es suficientemente conocida ni usada en nuestro medio. Se revisa la clasificación actual y la correlación con imágenes de aquellas anomalías vasculares situadas en partes blandas, dada la importancia que tiene un correcto diagnóstico para la terapéutica y pronóstico de los pacientes con estas lesiones.

Keloid heterograft in the hamster (mesocricetus auratus) cheek pouch

OBJETIVO: Investigar a integração do transplante heterólogo de quelóide na bolsa jugal do hamster (Mesocricetus auratus). MÉTODOS: A amostragem consiste de 18 hamsters machos, heterogênicos, com 10 a 14 semanas de idade. Fragmentos de quelóide foram obtidos de cicatrizes queloidianas da região mamária de paciente adulta parda. Cada hamster foi enxertado em ambas as bolsas com fragmentos de quelóide, totalizando 36 fragmentos enxertados. Os animais foram distribuídos em 6 grupos para exame dos fragmentos enxertados, com 5, 12, 21, 42, 84 e 168 dias. Uma avaliação macroscópica é realizada comparando a bolsa contendo o fragmento enxertado em cada período com a mesma bolsa no pós-operatório imediato, mediante a comparação de fotografias padronizadas. À microscopia, considera-se a presença de vasos sangüíneos no tecido conjuntivo do fragmento enxertado como critério de integração do mesmo. Outros eventos, como secreção de queratina, presença de infiltrados celulares e aspecto do epitélio e das fibras colágenas do quelóide, também são observados. RESULTADOS: A macroscopia revela intensa vascularização na bolsa até 12 dias de enxertia, e a presença constante de pigmentação castanho-escura nos fragmentos de quelóide enxertados. Na microscopia constata-se a integração dos fragmentos de quelóide pela presença de capilares sangüíneos no tecido conjuntivo. Observa-se, também, a presença de intenso infiltrado celular do tipo inflamatório até 12 dias, a permanência do epitélio do quelóide até 21 dias, e o aparecimento de melanócitos a partir de 42 dias. CONCLUSÃO: A bolsa jugal do hamster representa, a priori, modelo experimental para investigação do quelóide.