145 research outputs found

    Hyperbaric Oxygen Therapy Does Not Have a Negative Impact on Bone Signaling Pathways in Humans

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    Introduction: Oxygen is emerging as an important factor in the local regulation of bone remodeling. Some preclinical data suggest that hyperoxia may have deleterious effects on bone cells. However, its clinical relevance is unclear. Hence, we studied the effect of hyperbaric oxygen therapy (HBOT) on serum biomarkers reflecting the status of the Wnt and receptor activator of NF-?B ligand (RANKL) pathways, two core pathways for bone homeostasis. Materials and methods: This was a prospective study of 20 patients undergoing HBOT (mean age 58 yrs., range 35?82 yrs.) because of complications of radiotherapy or chronic anal fissure. Patients were subjected to HBOT (100% oxygen; 2.4 atmospheres absolute for 90 min). The average number of HBOT sessions was 20 ± 5 (range 8?31). Serum hypoxia-inducible factor 1-? (HIF1-?), osteoprotegerin (OPG), RANKL, and the Wnt inhibitors sclerostin and dickkopf-1 (DKK1) were measured at baseline and after HBOT by using specific immunoassays. Results: HIF-1? in eight patients with measurable serum levels increased from 0.084 (0.098) ng/mL at baseline to 0.146 (0.130) ng/mL after HBOT (p = 0.028). However, HBOT did not induce any significant changes in the serum levels of OPG, RANKL, sclerostin or DKK1. This was independent of the patients? diagnosis, either neoplasia or benign. Conclusion: Despite the potential concerns about hyperoxia, we found no evidence that HBOT has any detrimental effect on bone homeostasis

    Epidemiología molecular de Bartonella henselae en gatos callejeros y de albergue en Zaragoza, España

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    Fundamentos: Bartonella henselae produce la enfermedad del araña- zo del gato en las personas y se considera infradiagnosticada. El objetivo fue detectar y cuantificar la carga de ácido desoxiribonucleico (ADN) de B. henselae en muestras de sangre y orales de gatos callejeros y de albergue de Zaragoza, España y analizar su relación con factores epidemiológicos y clínicos. Métodos: Se estudiaron 47 gatos. El ADN de B. henselae,se detectó mediante reacción en cadena de la polimerasa en tiempo real (qPCR) en sangre y muestras orales. Se usó el paquete estadístico SPSS para analizar la positividad de las muestras pareadas y su relación con factores epidemioló- gicos (edad, sexo, origen, mes de muestreo, presencia de pulgas/garrapatas) y clínicos (estado de salud y presencia de lesiones orales). Se realizó un análisis de regresión logística para conocer la asociación entre la presencia en sangre y cavidad oral y el resto de las variables. Resultados: el 23,40% de las muestras de sangre y el 27,65% de las orales portaba el ADN de B. henselae. Se observó débil correlación de la positividad de las muestras pareadas (kappa= 0,33; p 0,05) entre la presencia de ADN de B. henselae en las muestras y los factores epidemiológicos y clínicos. Los gatos con lesiones orales portaban una carga más elevada de ADN (3,12/1x106 células) en la boca que los que no tenían lesiones (2,58 /1por106 células), (p=0,032). Conclusiones: La detección de ADN de B. henselae en sangre no pare- ce estar relacionada con su presencia en cavidad oral y viceversa. Los gatos positivos con lesiones orales pueden significar mayor riesgo de infección por B. henselae para las personas que los manejan

    Diverging results of areal and volumetric bone mineral density in Down syndrome

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    Population with Down syndrome (DS) has lower areal BMD, in association with their smaller skeletal size. However, volumetric BMD and other indices of bone microarchitecture, such as trabecular bone score (TBS) and calcaneal ultrasound (QUS), were normal. INTRODUCTION: Patients with DS have a number of risk factors that could predispose them to osteoporosis. Several studies reported that people with DS also have lower areal bone mineral density, but differences in the skeletal size could bias the analysis. METHODS: Seventy-five patients with DS and 76 controls without intellectual disability were recruited. Controls were matched for age and sex. Bone mineral density (BMD) was measure by Dual-energy X-ray Absorptiometry (DXA), and volumetric bone mineral density (vBMD) was calculated by published formulas. Body composition was also measured by DXA. Microarchitecture was measured by TBS and QUS. Serum 25-hidroxyvitamin D (25OHD), parathyroid hormone (PTH), aminoterminal propeptide of type collagen (P1NP), and C-terminal telopeptide of type I collagen (CTX) were also determined. Physical activity was assessed by the International Physical Activity Questionnaires (IPAQ-short form). To evaluate nutritional intake, we recorded three consecutive days of food. RESULTS: DS individuals had lower height (151 ± 11 vs. 169 ± 9 cm). BMD was higher in the controls (lumbar spine (LS) 0.903 ± 0.124 g/cm2 in patients and 0.997 ± 0.115 g/cm2 in the controls; femoral neck (FN) 0.761 ± .126 g/cm2 and 0.838 ± 0.115 g/cm2, respectively). vBMD was similar in the DS group (LS 0.244 ± 0.124 g/cm3; FN 0.325 ± .0.073 g/cm3) and the controls (LS 0.255 ± 0.033 g/cm3; FN 0.309 ± 0.043 g/cm3). Microarchitecture measured by QUS was slightly better in DS, and TBS measures were similar in both groups. 25OHD, PTH, and CTX were similar in both groups. P1NP was higher in the DS group. Time spent on exercise was similar in both groups, but intensity was higher in the control group. Population with DS has correct nutrition. CONCLUSIONS: Areal BMD is reduced in DS, but it seems to be related to the smaller body and skeletal size. In fact, the estimated volumetric BMD is similar in patients with DS and in control individuals. Furthermore, people with DS have normal bone microarchitecture

    Tribological behaviour of microalloyed and conventional C–Mn rail steels in a pure sliding condition

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    This paper compares the tribological behaviour of microalloyed rail steel with conventional C–Mn rail steel under different test conditions (load, temperature and humidity). Pin-on-disc tribological tests were performed inside a climate chamber under different loads (20, 30 and 40 N), relative humidity (15, 55 and 70%) and temperatures (20 and 40 ℃). After the friction and wear tests, the worn surfaces were analysed using both confocal and scanning electron microscopies. The results obtained show that the use of microalloyed steel in railway applications under severe conditions (high loads and humidity) could lead to increased service life of the rails and could extend the time between maintenance operations

    Genetic polymorphisms are associated with serum levels of sex hormone binding globulin in postmenopausal women

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    <p>Abstract</p> <p>Background</p> <p>Estrogen activity plays a critical role in bone homeostasis. The serum levels of sex hormone binding globulin (SHBG) influence free estrogen levels and activity on target tissues. The objective of this study was to analyze the influence of common polymorphisms of the <it>SHBG </it>gene on serum SHBG, bone mineral density (BMD), and osteoporotic fractures.</p> <p>Methods</p> <p>Four biallelic polymorphisms of the <it>SHBG </it>gene were studied by means of Taqman assays in 753 postmenopausal women. BMD was measured by DXA and serum SHBG was measured by ELISA.</p> <p>Results</p> <p>Age, body weight, and two polymorphisms of the <it>SHBG </it>gene (rs6257 and rs1799941 [A/G]) were significantly associated with serum SHBG in unadjusted and age- and weight-adjusted models. Alleles at the rs1799941 locus showed the strongest association with serum SHBG (p = 0.0004). The difference in SHBG levels between women with AA and GG genotypes at the rs1799941 locus was 39%. There were no significant differences in BMD across SHBG genotypes. The genotypes showed similar frequency distributions in control women and women with vertebral or hip fractures.</p> <p>Conclusion</p> <p>Some common genetic variants of the <it>SHBG </it>gene, and particularly an A/G polymorphism situated in the 5' region, influence serum SHBG levels. However, a significant association with BMD or osteoporotic fractures has not been demonstrated.</p
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