Bone tissue quality in patients with monoclonal gammopathy of uncertain significance.

INTRODUCTION: Monoclonal gammopathy of uncertain significance (MGUS) is highly prevalent in older adults and affects bone structure, with osteoporosis and increased risk of fractures in up to 14% of affected patients. Dual-energy X-ray absorptiometry (DXA), the standard technique for diagnosing osteoporosis, is ineffective to reveal microstructure and bone quality in this disease. MATERIALS AND METHODS: We conducted a cross-sectional study of patients with MGUS, recruited consecutively from the Hematology and Internal Medicine Departments of Hospital del Mar, Barcelona, between January 2011 and January 2018. Medical records, clinical results and spinal X-ray images were collected. Bone mineral density (BMD) at hip and spine was measured by DXA and Bone Material Strength index (BMSi) by impact microindentation on the tibial mid-shaft. RESULTS: Thirty-nine patients with MGUS and 65 age-matched controls without previous fractures were included. In the MGUS group, 11 (28.2%) patients had prevalent fractures, nearly half of them vertebral (n = 5, 45.45%). Compared to controls, MGUS patients had significantly lower BMSi, a mean (SD) of 70.72 (9.70) vs. 78.29 (8.70), p = 0.001, and lower spinal BMD values (0.900 [0.159] vs. 1.003 [0.168], respectively, p = 0.012), but no significant differences at femoral neck and total hip. No association was observed between BMSi and DXA. Bone remodeling markers (procollagen type-1 N propeptide, bone-alkaline phosphatase and C-terminal telopeptide of type I collagen) did not differ between the two groups. CONCLUSIONS: Spinal BMD and mechanical properties of bone tissue, as measured by impact microindentation, were impaired in patients with MGUS. These changes in bone tissue mechanical resistance were independent of DXA levels.

Cortical and Trabecular Bone Analysis of Patients With High Bone Mass From the Barcelona Osteoporosis Cohort Using 3-Dimensional Dual-Energy X-ray Absorptiometry: A Case-Control Study.

High bone mass (HBM), a rare phenotype, can be detected by dual-energy X-ray absorptiometry (DXA) scanning. Measurements with peripheral quantitative computed tomography at the tibia have found increased trabecular bone mineral density and changes in cortical bone density and structure, all of which lead to increased bone strength. However, no studies on cortical and trabecular bone have been performed at the femur. The recently developed 3-dimensional (3D)-DXA software algorithm quantifies the trabecular and cortical volumetric bone mineral density (vBMD) and the anatomical distribution of cortical thickness using routine hip DXA scans. We analyzed the femurs of 15 women with HBM and 15 controls from the Barcelona Osteoporosis (BARCOS) cohort using the 3D-DXA technique. The mean vBMD of proximal femur was 29.7% higher in HBM cases than in controls for the integral bone, 41.3% higher for the trabecular bone, and 7.3% higher for the cortical bone (p < 0.001). No differences in bone size were detected between cases and controls. Patients with HBM had a thicker cortex and higher trabecular and cortical vBMDs, as measured by 3D-DXA at the femur and compared to controls; bone size was similar in both groups. To the best of our knowledge, this is the first description of trabecular and cortical characteristics of the hip in patients with HBM.

Mujer de 31 años con lesiones osteolíticas múltiples asociadas a afectación linfática tisular / 31 years old woman with multiple osteolytic lesions associated with lymphatic tissue damage

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Ixodid ticks (Acari: Ixodidae) present at Parque Nacional El Rey, Argentina / Carrapatos (Acari: Ixodidae) do Parque Nacional El Rey, Argentina

Information on autochthonous ticks and their hosts is scarce in South America, especially in Argentina. To contribute to tick knowledge in the region, 2094 ticks were collected from the vegetation, humans, domestic and wild animals at a host-and-tick rich area of northern Argentina during six field trips conducted in 1999 (January and August), 2000 (March and November), and 2001 (March and June). The ticks were identified as Amblyomma cajennense (Fabricius), Amblyomma coelebs Neumann, Amblyomma sp., Haemaphysalis juxtakochi Cooley, H. leporispalustris (Packard), Ixodes pararicinus Keirans & Clifford, I. loricatus Neumann, I. longiscutatum Boero and Ixodes sp. Small mammals were mainly parasitized by immature stages of Ixodes; humans and domestic animals, predominantly by Amblyomma spp., and birds, mainly by nymphs and larvae of Haemaphysalis spp.

Informações sobre carrapatos autóctones e seus hospedeiros são escassas na América do Sul, especialmente para a Argentina. Com o objetivo de contribuir para o conhecimento dos carrapatos na região, 2094 carrapatos foram coletados da vegetação, de humanos e de animais domésticos e selvagens numa área no norte da Argentina rica em carrapatos e hospedeiros, durante seis viagens de campo conduzidas em 1999 (janeiro e agosto), 2000 (março e novembro) e 2001 (março e junho). Os carrapatos foram identificados como Amblyomma cajennense (Fabricius), A. coelebs Neumann, Amblyomma sp., Haemaphysalis juxtakochi Cooley, H. leporispalustris (Packard), Ixodes pararicinus Keirans & Clifford, I. loricatus Neumann, I. longiscutatum Boero e Ixodes sp. Pequenos mamíferos foram principalmente parasitados por estágios imaturos de Ixodes; humanos e animais domésticos, predominantemente por Amblyomma spp., e pássaros, principalmente por ninfas e larvas de Haemaphysalis spp.