Effect of propranolol on capsular reaction around silicone implants in guinea pigs

PURPOSE: To evaluate the effect of propranolol on capsular architecture around silicone implants by measuring the inflammation, capsular thickness, and collagen fiber density, using a guinea pig experimental model. METHODS: Thirty six adult male guinea pigs randomly divided into two groups (n=18) were used. Each one received a silicone implant with textured-surface. The capsular tissue around implants from untreated or treated animals with the beta-adrenoceptor antagonist propranolol (10 mg/kg, dissolved in daily water) were analyzed for inflammation by histological scoring, capsular thickness by computerized histometry, and collagen fibers type I and Type III density by picrosirius polarization at different time points (7, 14 or 21 days after silicone implantation).RESULTS: Propranolol treatment reduced inflammation and impaired capsular thickness and delayed collagen maturation around the textured implant. CONCLUSION: Propranolol reduces the risk of developing capsular contracture around silicone implants with textured surface.(AU)

Histological study of rat ovaries cryopreserved by vitrification or slow freezing and reimplanted in the early or late postmenopausal stage

To compare two rat ovary cryopreservation techniques (vitrification vs. slow freezing) and two postmenopausal stages (early vs. late) with regard to graft take. Thirty-three Wistar rats were submitted to bilateral oophorectomy. One ovary was submitted to histological analysis while the other was cryopreserved by slow freezing or vitrification. The cryopreserved ovary was thawed and reimplanted in the greater omentum one week (early menopause) or one month (late menopause) after oophorectomy. One month after ovary reimplantation, the graft take was evaluated macroscopically and histologically. Six of the animals were used ascontrols and seven died. The histological findings of 20 animals included atretic follicles (n=4), primordial follicles (n=2), and corpus luteum with primordial follicles (n=3). No ovarian tissue was found in 11 animals. Vitrification resulted in a higher graft take rate than slow freezing (50% vs. 38.5%), but the difference was not statistically significant. However, the graft take rate was 9.3 times higher in the early than in the late postmenopausal stage (61.5% vs. 14.3%) (p=0.043). Vitrification was superior to slow freezing as ovarian cryopreservation technique, and grafting was significantly more successful when the ovary was reimplanted in the late postmenopausal stage.(AU)

Biomechanical properties of the biceps-labral complex submitted to mechanical stress / Propriedades biomecânicas do complexo labrum-glenóide bicipital superior submetido ao estresse mecânico

OBJETIVO: Determinar as propriedades biomecânicas do complexo labrum-glenóide bicipital superior submetido ao estresse mecânico contínuo ou repetitivo (repentino).MÉTODOS: Dezoito ombros provenientes de 15 cadáveres não reclamados, idades na faixa de 20 a 40 anos, foram submetidos aos testes de tração contínua ou repentina usando três diferentes máquinas de tração. Foram excluídos do estudo os ombros que apresentavam lesões degenerativas ou evidências de lesões traumáticas pré-existentes.RESULTADOS: Ocorreu ruptura da porção distal do tendão do bíceps sob a tensão contínua de 290 N e de 348N na tração repentina. Não foram observadas lesões no complexo labrum-bicipital.CONCLUSÃO: A simples tração contínua ou súbita do braço não produz lesões do complexo Labrum Glenóide Bicipital Superior (SLAP) na articulação do ombro.(AU)

PURPOSE: To determine biomechanical properties of the superior labrum-biceps tendon complex submitted to continuous and sudden mechanical strain. METHODS: Eighteen shoulder specimens from 15 unclaimed corpses, ages ranging from 20 to 40 years, were submitted to continuous or sudden tensile tests using 3 different traction machines. Shoulders presenting signs of degenerative diseases or preexisting traumatic lesions were excluded. RESULTS: Rupture of the distal portion of the long hand of the biceps occurred when stretching forces reached 290N in continuous traction and 384N in sudden traction. No labral-complex lesions were observed. CONCLUSION: Either a simple continuous or a sudden uniaxial traction of the arm do not play a role in the genesis of superior labrum anterior-posterior (SLAP) lesions in the shoulder joint produce.(AU)