Assessment of irradiated socket healing in the rabbit's mandible: Experimental study.

As bone healing is altered after external radiation therapy, its evaluation is mandatory and lacks in clinical practice. The aim of the pilot study was to validate micro computed tomography (microCT) as a simple and reliable technique for assessing irradiated bone healing in the rabbit's mandible and compare with histologic findings. Nineteen rabbits (female New Zealand white) were used. The radiation protocol consisted of 5 sessions delivering 8.5 Gy each. MicroCT was performed at D0, D7, D14, D28 and D42 for the control group and D0, D28 and D42 for the irradiated group. A modified Perry's score was determined on histologic samples, and comparison between microCT and histological findings was performed. The main differences between irradiated and non-irradiated rabbits were observed at Day 28 and 42. There was a strong correlation between imaging and histologic findings. Radiation decreases bone quality and bone mineral density. As the correlation was strong between microCT and histologic findings, micro imaging could be considered as a simple and reliable technique to assess bone healing after radiation therapy and allows an easy comparison between samples, without invasive procedures. Great attention should be kept on the parameters and on the region of interest. The development of in-vivo microCT enlarges the perspectives of microCT use in experimental studies, avoiding invasive procedures, and preserving animal lives and well-being, and furthermore lead to clinical applications.

ASSESSMENT OF THE LATE EFFECTS ON BONES AND ON BODY COMPOSITION OF CHILDREN AND ADOLESCENTS TREATED FOR ACUTE LYMPHOCYTIC LEUKEMIA ACCORDING TO BRAZILIAN PROTOCOLS. / AVALIAÇÃO DOS EFEITOS ÓSSEOS TARDIOS E COMPOSIÇÃO CORPORAL DE CRIANÇAS E ADOLESCENTES TRATADOS DE LEUCEMIA LINFOIDE AGUDA SEGUNDO PROTOCOLOS BRASILEIROS.

OBJECTIVE: To evaluate the impact of therapy on bone mineral density (BMD) and body composition in survivors of acute lymphoblastic leukemia (ALL) treated in accordance with Brazilian protocols by the Brazilian Cooperative Group of Treatment of Lymphoblastic Leukemia in Childhood (GBTLI) LLA-93 and LLA-99. METHODS: A cross-sectional study with 101 patients was performed. BMD and body composition were evaluated using bone densitometry and were interpreted according to the age group and the reference population. Values between -1.1 and -1.9 in the group of children under 20 years were considered as risk group for low BMD z-scores. BMD values were compared to clinical characteristics, treatment received and body composition. A chi-square test, Fisher's exact test, likelihood ratio and Student's t-test were applied, with a 5% significance level. RESULTS: The patients presented a frequency of fractures of 2%, of osteonecrosis, 2%, and of low BMD, 2.9%. In the group of 79 patients under 20 years of age, three had low BMD. The 16 that presented risk for low BMD, demonstrated lower valutes in lumbar vertebrae L1-L4 (p=0.01) and whole body (p=0.005), and smaller values of lean body mass (p=0.03). In the group of 22 patients over 20 years of age, ten had osteopenia. CONCLUSIONS: The low impact of treatment on BMD of this study confirms the concept that the bone mass gain occurs with increasing age and that the treatment does not influence the process. The population at risk for low BMD values presented lower bone mass values and could benefit from a long-term monitoring for possible bone toxicity.

OBJETIVO: Avaliar o impacto da terapia sobre a densidade mineral óssea (DMO) e composição corporal em sobreviventes da leucemia linfoide aguda (LLA), tratados de acordo com os protocolos brasileiros do Grupo Cooperativo Brasileiro de Tratamento de Leucemia Linfoide Aguda na Infância (GBTLI), LLA-93 e LLA-99. MÉTODOS: Em estudo transversal com 101 pacientes, avaliaram-se a composição corporal e a DMO por meio da densitometria óssea, interpretando-a conforme a faixa etária e a população de referência. Foi considerado grupo de risco para baixa DMO valores de z-escore entre -1,1 e -1,9 no grupo dos menores de 20 anos. Compararam-se os valores da DMO com características clínicas, tratamento recebido e composição corporal. Foram utilizados os testes qui-quadrado, exato de Fisher, razão de verossimilhança e t de Student, com nível de significância de 5%. RESULTADOS: Foram encontradas 2% de fraturas, 2% de osteonecrose e 2,9% de baixa DMO. No grupo de pacientes com menos de 20 anos, três apresentaram baixa DMO. Os 16 pacientes com risco para baixa DMO exibiram menores valores em vértebras lombares L1-L4 (p=0,01), corpo total (p=0,005) e valores mais baixos de massa magra (p=0,03). No grupo de 22 pacientes com mais de 20 anos, dez demonstraram osteopenia. CONCLUSÕES: O baixo impacto do tratamento sobre a DMO neste estudo ratifica o conceito de que o ganho de massa óssea ocorre com o aumento da idade e que o tratamento não influencia tal processo. A população de risco para baixa DMO demonstrou valores menores de massa óssea, podendo beneficiar-se de um acompanhamento em longo prazo para uma possível toxicidade óssea.

AVALIAÇÃO DOS EFEITOS ÓSSEOS TARDIOS E COMPOSIÇÃO CORPORAL DE CRIANÇAS E ADOLESCENTES TRATADOS DE LEUCEMIA LINFOIDE AGUDA SEGUNDO PROTOCOLOS BRASILEIROS / ASSESSMENT OF THE LATE EFFECTS ON BONES AND ON BODY COMPOSITION OF CHILDREN AND ADOLESCENTS TREATED FOR ACUTE LYMPHOCYTIC LEUKEMIA ACCORDING TO BRAZILIAN PROTOCOLS

RESUMO Objetivo: Avaliar o impacto da terapia sobre a densidade mineral óssea (DMO) e composição corporal em sobreviventes da leucemia linfoide aguda (LLA), tratados de acordo com os protocolos brasileiros do Grupo Cooperativo Brasileiro de Tratamento de Leucemia Linfoide Aguda na Infância (GBTLI), LLA-93 e LLA-99. Métodos: Em estudo transversal com 101 pacientes, avaliaram-se a composição corporal e a DMO por meio da densitometria óssea, interpretando-a conforme a faixa etária e a população de referência. Foi considerado grupo de risco para baixa DMO valores de z-escore entre -1,1 e -1,9 no grupo dos menores de 20 anos. Compararam-se os valores da DMO com características clínicas, tratamento recebido e composição corporal. Foram utilizados os testes qui-quadrado, exato de Fisher, razão de verossimilhança e t de Student, com nível de significância de 5%. Resultados: Foram encontradas 2% de fraturas, 2% de osteonecrose e 2,9% de baixa DMO. No grupo de pacientes com menos de 20 anos, três apresentaram baixa DMO. Os 16 pacientes com risco para baixa DMO exibiram menores valores em vértebras lombares L1-L4 (p=0,01), corpo total (p=0,005) e valores mais baixos de massa magra (p=0,03). No grupo de 22 pacientes com mais de 20 anos, dez demonstraram osteopenia. Conclusões: O baixo impacto do tratamento sobre a DMO neste estudo ratifica o conceito de que o ganho de massa óssea ocorre com o aumento da idade e que o tratamento não influencia tal processo. A população de risco para baixa DMO demonstrou valores menores de massa óssea, podendo beneficiar-se de um acompanhamento em longo prazo para uma possível toxicidade óssea.

ABSTRACT Objective: To evaluate the impact of therapy on bone mineral density (BMD) and body composition in survivors of acute lymphoblastic leukemia (ALL) treated in accordance with Brazilian protocols by the Brazilian Cooperative Group of Treatment of Lymphoblastic Leukemia in Childhood (GBTLI) LLA-93 and LLA-99. Methods: A cross-sectional study with 101 patients was performed. BMD and body composition were evaluated using bone densitometry and were interpreted according to the age group and the reference population. Values between -1.1 and -1.9 in the group of children under 20 years were considered as risk group for low BMD z-scores. BMD values were compared to clinical characteristics, treatment received and body composition. A chi-square test, Fisher’s exact test, likelihood ratio and Student’s t-test were applied, with a 5% significance level. Results: The patients presented a frequency of fractures of 2%, of osteonecrosis, 2%, and of low BMD, 2.9%. In the group of 79 patients under 20 years of age, three had low BMD. The 16 that presented risk for low BMD, demonstrated lower valutes in lumbar vertebrae L1-L4 (p=0.01) and whole body (p=0.005), and smaller values of lean body mass (p=0.03). In the group of 22 patients over 20 years of age, ten had osteopenia. Conclusions: The low impact of treatment on BMD of this study confirms the concept that the bone mass gain occurs with increasing age and that the treatment does not influence the process. The population at risk for low BMD values presented lower bone mass values and could benefit from a long-term monitoring for possible bone toxicity.

Quality assessment for processed and sterilized bone using Raman spectroscopy.

To eliminate the potential for infection, many tissue banks routinely process and terminally sterilize allografts prior to transplantation. A number of techniques, including the use of scanning electron microscopy, bone graft models, and mechanical property tests, are used to evaluate the properties of allograft bone. However, as these methods are time consuming and often destroy the bone sample, the quality assessment of allograft bones are not routinely performed after processing and sterilization procedures. Raman spectroscopy is a non-destructive, rapid analysis technique that requires only small sample volumes and has recently been used to evaluate the mineral content, mineral crystallinity, acid phosphate and carbonate contents, and collagen maturity in human and animal bones. Here, to establish a quality assessment method of allograft bones using Raman spectroscopy, the effect of several common sterilization and preservation procedures on rat femoral bones were investigated. We found that freeze-thawing had no detectable effects on the composition of bone minerals or matrix, although heat treatment and gamma irradiation resulted in altered Raman spectra. Our findings suggest Raman spectroscopy may facilitate the quality control of allograft bone after processing and sterilization procedures.

Quantitative histomorphometric assessment of regenerate cellularity and bone quality in mandibular distraction osteogenesis after radiation therapy.

BACKGROUND: The use of mandibular distraction osteogenesis (MDO) for tissue replacement after oncologic resection in head and neck cancer could have immense therapeutic ramifications. We have previously demonstrated significantly decreased mechanical and microdensitomeric metrics of our MDO regenerate after 36-Gy radiation. Quantitative histomorphometry, a third metric, would permit objective investigation of the effects of radiation on tissue and cellular composition. Our hypothesis is that radiation-induced cellular depletion and diminution in function impair optimal bone regeneration. METHODS: Five rats received radiation to the left mandible; 5 received none. All animals underwent surgical placement of external fixators, creation of mandibular osteotomies, distraction to a 5.1-mm gap width, and consolidation. Point counting and color thresholding were performed. RESULTS: There was a significant increase in empty lacunae and a corresponding diminution in osteocytes after radiation. Whereas the volume fraction of mineralized, mature bone was not different, that of nonmineralized, immature osteoid was significantly increased in the radiated group compared with that in the nonradiated group. CONCLUSIONS: Our findings confirm our prior 2 metrics. Actually, all 3 diverse metrics--microdensitometry, biomechanical analysis, and histomorphometry--corroborate our hypothesis of cellular depletion and diminution of function as the potential mechanism of radiation-induced attenuation in the distracted regenerate. Furthermore, our findings of tissue and cellular changes in the irradiated regenerate elucidate the pathophysiology of decreased bone quality when amalgamated with our previous results. Therapeutic agents may now be introduced, and their effects on the irradiated regenerate critically measured, so that MDO may be used as a viable reconstructive option in patients with head and neck cancer.

[The percutaneous irradiation of osteolytic bone metastases--a course assessment]. / Perkutane Radiatio osteolytischer Knochenmetastasen--eine Verlaufsbeurteilung.

Percutaneous radiotherapy is the most effective modality for treatment of metastatic bone cancer. Local irradiation improves overall quality of life by relieving pain in most patients. It also helps preventing complications as pathological fractures in lytic bone lesions by new bone formation. In a retrospective study on 100 patients, irradiated for lytic bone metastases, the radiotherapeutic effect on alleviation of pain and on recalcification rate was investigated. In our experience in 84% of the cases pain and disability associated with bone metastases could be decreased. 38% of the patients had complete relief of symptoms. A correlation between subjective therapy effect and histology of the primary tumor was not demonstrated. Remineralization was found in 67% of all irradiated skeletal areas (n = 137) (recalcification rate in breast cancer 77%, in bronchial carcinoma 27%, and in renal cell carcinoma 25%). After a total dose of 30 Gy reduction of the metastases-associated pain was achieved in 81% of the cases and remineralization was observed in 70% of the cases.