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Biomedical subjects

R M R Pereira

Publications and source records attributed to R M R Pereira.

7 recordsLinked to original sources
PubMed2006

Balance training program is highly effective in improving functional status and reducing the risk of falls in elderly women with osteoporosis: a randomized controlled trial.

INTRODUCTION: The purpose of this study was to investigate the effect of a 12-month Balance Training Program on balance, mobility and falling frequency in women with osteoporosis. METHODS: Sixty-six consecutive elderly women were selected from the Osteometabolic Disease Outpatient Clinic and randomized into 2 groups: the 'Intervention', submitted for balance training; and the 'Control', without intervention. Balance, mobility and falling frequency were evaluated before and at the end of the trial, using the Berg Balance Scale (BBS), the Clinical Test Sensory Interaction Balance (CTSIB) and the Timed "Up & Go" Test (TUGT). Intervention used techniques to improve balance consisting of a 1-hour session each week and a home-based exercise program. RESULTS: Sixty women completed the study and were analyzed. The BBS difference was significant higher in the Intervention group compared to Control (5.5 +/- 5.67 vs -0.5 +/- 4.88 score, p<0.001). Similarly, the number of patients in the Intervention group presented improvement in two conditions of CTSIB compared to Control (eyes closed and unstable surface condition: 13 vs one patient, p < 0.001 and eyes open, visual conflict and unstable surface condition: 12 vs one patient, p<0.001). Additionally, the differences between the TUGT were reduced in the Intervention group compared to Control (-3.65 +/- 3.61 vs 2.27 +/- 7.18 seconds, p< 0.001). Notably, this improvement was paralleled by a reduction in the number of falls/patient in the Intervention group compared to Control (-0.77 +/- 1.76 vs 0.33 +/- 0.96, p=0.018). CONCLUSION: This longitudinal prospective study demonstrated that an intervention using balance training is effective in improving functional and static balance, mobility and falling frequency in elderly women with osteoporosis.

Accidental Falls↗
PubMed2006

Comparative study of axial and femoral bone mineral density and parameters of mandibular bone quality in patients receiving dental implants.

INTRODUCTION: In view of the increase in the life expectancy of humans and in edentulism of the population above 50 years of age, in which the prevalence of osteoporosis is also higher, it is fundamental to better understand the effects of systemic bone mass loss on the healing process of dental implants and to determine the quality of the bone that surrounds them. The objective of the present study was to compare systemic osteoporosis (axial and femoral) and parameters of mandibular bone quality, and to evaluate osseointegration in postmenopausal women receiving dental implants. METHODS: The sample consisted of 39 women aged 48-70 years, 19 with a densitometric diagnosis of osteoporosis in the lumbar spine and femoral neck and 20 controls with a normal densitometric diagnosis. Bone mineral density was measured in the patients and controls by dual-energy X-ray absorptiometry. Eighty-two osseointegrated dental implants were placed in the mandible, 39 of them in the osteoporosis group and 43 in the control group. Mandibular bone quality was evaluated by classifying mandibular inferior cortical and trabecular bone on panoramic radiographs and by histomorphometric analysis of a mandibular bone biopsy. Osseointegration was analyzed after 9 months. RESULTS: No significant difference was observed between patients with osteoporosis and controls when comparing individuals with a normal cortex and those with a severely or moderately eroded cortex determined on panoramic radiographs. Histomorphometric analysis also revealed no difference in the parameters of bone formation or resorption between the two groups. Implant failure was observed in only one case. CONCLUSION: We conclude that there is no association between systemic osteoporosis (axial and femur) and parameters of poor mandibular bone quality. The loss of one implant (1.2%) is compatible with the literature and cannot be attributed to systemic osteoporosis.

Aged↗
PubMed2005

Low bone density and low serum levels of soluble RANK ligand are associated with severe arterial calcification in patients with Takayasu arteritis.

OBJECTIVE: Takayasu arteritis (TA) is a chronic inflammatory disorder affecting the aorta and its branches. Vascular calcification has been described in 29-54% of cases of TA, although its aetiology remains unknown. Recently the osteoprotegerin/RANKL/RANK system has emerged as an important contributing factor to atherogenesis and osteogenesis. Our aim is to investigate the association between vascular calcification, bone mineral density (BMD) and the osteoprotegerin/RANK/RANKL system in TA. METHODS: Thirty pre-menopausal female TA patients and 30 age- and sex-matched controls were studied. BMD was measured by dual X-ray absorptiometry. Arterial calcification in TA patients was analysed by computed tomography in thoracic and abdominal sites. Serum levels of osteoprotegerin and soluble receptor activator of nuclear factor kappaB ligand (sRANKL) were quantified by enzyme-linked immunosorbent assay. RESULTS: Patients with severe arterial calcification showed lower BMD values than controls in lumbar spine (0.965 +/- 0.055 vs 1.126 +/- 0.153 g/cm2, P = 0.009) and total body (0.993 +/- 0.065 vs 1.085 +/- 0.082 g/cm2, P = 0.019). In contrast, TA patients without calcification presented BMD values similar to controls (P > 0.05). Interestingly, lower serum levels of sRANKL (1.89 +/- 2.35 vs 2.80 +/- 2.23 pg/ml, P = 0.031) and a longer disease duration (12.20 +/- 6.61 vs 3.56 +/- 5.33 yr, P = 0.004) were observed in TA patients with severe calcification compared with patients without calcification. CONCLUSIONS: Severe arterial calcification in TA is associated with low values of BMD and sRANKL, reinforcing the possible link between bone and vascular disease.

Adult↗
PubMed2005

RANK, RANKL and osteoprotegerin in arthritic bone loss.

Rheumatoid arthritis is characterized by the presence of inflammatory synovitis and destruction of joint cartilage and bone. Tissue proteinases released by synovia, chondrocytes and pannus can cause cartilage destruction and cytokine-activated osteoclasts have been implicated in bone erosions. Rheumatoid arthritis synovial tissues produce a variety of cytokines and growth factors that induce monocyte differentiation to osteoclasts and their proliferation, activation and longer survival in tissues. More recently, a major role in bone erosion has been attributed to the receptor activator of nuclear factor kappa B ligand (RANKL) released by activated lymphocytes and osteoblasts. In fact, osteoclasts are markedly activated after RANKL binding to the cognate RANK expressed on the surface of these cells. RANKL expression can be upregulated by bone-resorbing factors such as glucocorticoids, vitamin D3, interleukin 1 (IL-1), IL-6, IL-11, IL-17, tumor necrosis factor-alpha, prostaglandin E2, or parathyroid hormone-related peptide. Supporting this idea, inhibition of RANKL by osteoprotegerin, a natural soluble RANKL receptor, prevents bone loss in experimental models. Tumor growth factor-beta released from bone during active bone resorption has been suggested as one feedback mechanism for upregulating osteoprotegerin and estrogen can increase its production on osteoblasts. Modulation of these systems provides the opportunity to inhibit bone loss and deformity in chronic arthritis.

Animals↗
PubMed2004

Overexpression of insulin-like growth factor binding protein-5 decreases osteoblastic function in vitro.

Skeletal cells synthesize insulin-like growth factors (IGF) and their binding proteins (IGFBP). The effects of IGFBP-5 on bone cell growth and osteoblastic function are controversial, and transgenic mice overexpressing IGFBP-5 exhibit osteopenia. The mechanisms were not explored, and in this study, we investigated the effects of IGFBP-5 overexpression in MC3T3 cells in vitro. MC3T3 cells were transduced with a retroviral vector (pLPCX) or a vector directing IGFBP-5 transcription under the control of a constitutive promoter. Untreated MC3T3 cells expressed alkaline phosphatase, and osteocalcin mRNA 1 week after confluence and at 4 weeks of culture they formed mineralized nodules. IGFBP-5 overexpression delayed the appearance of alkaline phosphatase and osteocalcin mRNA, decreased type I collagen and osteopontin mRNA and alkaline phosphatase activity (APA), and inhibited the formation of mineralized nodules. IGFBP-5 caused a modest stimulation of DNA synthesis. In conclusion, overexpression of IGFBP-5 decreases osteoblastic function possibly by binding IGFs in the bone microenvironment.

3T3 Cells↗
PubMedDate not supplied

Systemic sclerosis and bone loss: the role of the disease and body composition.

OBJECTIVES: Studies on body composition are not available in systemic sclerosis (SSc). As this variable may play an important role in bone loss we have analysed bone mineral density (BMD) and body composition in SSc patients and healthy controls. METHODS: Forty-three postmenopausal SSc patients and 47 healthy postmenopausal women were studied. Patients with intestinal malabsorption, renal failure, current or past history of smoking or using osteopenic drugs were excluded. BMD and body composition was evaluated by dual X-ray absorptiometry (DXA). RESULTS: A higher frequency of osteoporosis in the lumbar spine (32.5%) and femoral neck (51.1%) was observed in SSc patients when compared to controls (14.8% vs. 19.1%; p<0.01). Multiple linear regression analysis revealed an association between the presence of SSc and low BMD. Body composition showed a reduced lean mass (33.15 vs. 39.99 g; p<0.01) and fat mass (21.05 vs. 26.82 g; p<0.01) in SSc when compared to controls. Lean mass was an important factor related to BMD in the lumbar spine and femoral neck. CONCLUSION: SSc may be an independent factor for low BMD. The low lean mass in these patients emphasizes the need for appropriate additional therapeutic measures to reduce bone loss in SSc patients.

Absorptiometry, Photon↗