ABSTRACT
PURPOSE: To study the main effects of local use of liquid nitrogen on bone marrow tissue in rats. METHODS: The femoral diaphyses of 42 Wistar rats were exposed to three local and sequential applications of liquid nitrogen for one or two minutes, intercalated with periods of five minutes of passive thawing. The animals were sacrificed after one, two, four and 12 weeks and the specimens obtained were analyzed histomorphologically. RESULTS: In the second experimental week of one-minute protocol, histological degree of inflammation obtained a mean score of one (mild), ranging from 0 (absent or scarce) and two (moderate) (Kruskal-Wallis test p=0.01). In the second experimental week of two-minute protocol, degree of inflammation to the medullar tissue obtained an average score of two (Kruskal-Wallis test p=0.01). CONCLUSION: The degree of inflammation of the bone marrow tissue was higher in protocol of three applications of two minutes compared to protocol of three applications of one minute.
OBJETIVO: Investigar os principais efeitos do uso local de nitrogênio líquido sobre o tecido medular ósseo em ratos. MÉTODOS: As diáfises femorais de 42 ratos Wistar foram expostas a três aplicações sequenciais locais de nitrogênio líquido por um ou dois minutos, intercaladas por períodos de cinco minutos de degelo espontâneo. Os animais foram sacrificados após uma, duas, quatro e 12 semanas e os espécimes obtidos foram analisados histomorfologicamente. RESULTADOS: Na segunda semana experimental do protocolo de um minuto, o grau histológico de inflamação obteve um escore médio de um (leve) variando entre 0 (ausente ou escarço) a dois (moderado) (Teste de Kruskal-Wallis p=0.01). Na segunda semana experimental do protocolo de dois minutos, o grau histológico de inflamação do tecido medular obteve um escore máximo de dois (moderado) (Teste de Kruskal-Wallis p=0.01). CONCLUSÃO: O grau de inflamação do tecido medular ósseo foi maior no protocolo de três aplicações de dois minutos comparado ao protocolo de três aplicações de um minuto.
Subject(s)
Animals , Male , Rats , Bone Marrow/drug effects , Cryotherapy/methods , Femur/drug effects , Nitrogen/pharmacology , Bone Marrow/pathology , Bone and Bones/drug effects , Bone and Bones/pathology , Cryosurgery/methods , Disease Models, Animal , Diaphyses/drug effects , Diaphyses/pathology , Femur/pathology , Nitrogen/therapeutic use , Osteomyelitis/pathology , Rats, Wistar , Time Factors , Treatment OutcomeABSTRACT
Bisphosphonates are potent inhibitors of bone resorption and widely used to treat osteoporosis. Extensive studies have shown that therapy with bisphosphonates improves bone density and decreases fracture risk. However, concerns have been raised about potential over-suppression of bone turnover during long-term use of bisphosphonates, resulting in increased susceptibility to and delayed healing of non-spinal fractures. We report a patient who sustained non-traumatic stress fractures in bilateral femoral shafts with delayed healing after long-term bisphosphonate therapy. She underwent open reduction and surgical internal fixation. Although bisphosphonates effectively prevent vertebral fractures, and their safety has been tested in randomized trials, we must emphasize the need for awareness of the possibility that long-term suppression of bone turnover with bisphosphonates may eventually lead to an accumulation of fatigue-induced damage and adverse skeletal effects such as delayed fracture healing.
Subject(s)
Female , Humans , Middle Aged , Bone Density/drug effects , Diaphyses/drug effects , Diphosphonates/adverse effects , Femoral Fractures/chemically induced , Fracture Fixation, Internal , Fracture Healing/drug effects , Fractures, Spontaneous/chemically induced , Fractures, Stress/chemically induced , Osteoporosis/drug therapy , Radiopharmaceuticals , Technetium Tc 99m Medronate/analogs & derivatives , Treatment Outcome , Whole Body ImagingABSTRACT
The development of the interface formed upon grafing porous hydroxyapatite ceramic in diaphyseal defecta of rabbits was assessed. An experimental study involved 24 animals where the right defected ulnae were grafted with the ceramic and compared with the left defect ungrafted serving as contralateral control site. Interfaces were examined for animals sacrificed after 12 and 18 weeks implantation. Scanning electron microscopy [SEM] was used to examine longitudinal sections [LS] passing the bone/graft interface [I], as well as those passing the middle [M] of the graft. The horizontal ones [HS] passing the graft with the developed structures were also studied. The pull- out technique was adopted to test the interface tensile strength of the grafts obtained from animals sacrified at 18 weeks in comparison with normal bone. Results were complimented radiologically and histologically. Results of the [LS] at the interface revealed direct apposition of the newly formed bone represented by a network of woven bone filing areas of contact. The porous structure of the hydroxyapatite implant facilitated bone infiltration. The importance of variable pore sizes was reflected as closure of some pores was completed by the newly formed biologic hydroxyapatite implant [HS]. Others are starting to show growth from the periphery of the wall of the pores via their cores. No signs of fibrous tissue or encapsulation could be observed accompanying the healing process while clearly shown in control site. The developed interface acquired 60% of the tensile strength of normal bone. This could be improved by long implantation period and or introduction of some morphogenic factors