Search results for " Density"
showing 10 items of 2709 documents
The impact of isolated lesions on white-matter fiber tracts in multiple sclerosis patients
2015
Infratentorial lesions have been assigned an equivalent weighting to supratentorial plaques in the new McDonald criteria for diagnosing multiple sclerosis. Moreover, their presence has been shown to have prognostic value for disability. However, their spatial distribution and impact on network damage is not well understood. As a preliminary step in this study, we mapped the overall infratentorial lesion pattern in relapsing–remitting multiple sclerosis patients (N = 317) using MRI, finding the pons (lesion density, 14.25/cm3) and peduncles (13.38/cm3) to be predilection sites for infratentorial lesions. Based on these results, 118 fiber bundles from 15 healthy controls and a subgroup of 23 …
Age-dependence of bone material quality shown by the measurement of frequency of resonance in the ulna
1994
In women before and after the age of peak bone mass, identical values of bone mineral density (BMD) can be obtained. However, there is a much higher incidence of osteoporotic fractures in older women. We investigated whether a deterioration of bone material quality with increasing age might contribute to this phenomenon. Material properties of bone tissue can be characterized by the modulus of elasticity, which is correlated to the square of sound transmission velocity. In this study, sound transmission velocity was determined in cortical bone by measuring the frequency of resonance in the ulna in the direction of the bone's longitudinal axis and correcting the values by multiplying by ulna…
Trait-specific tracking and determinants of body composition: a 7-year follow-up study of pubertal growth in girls
2008
Abstract Background Understanding how bone (BM), lean (LM) and fat mass (FM) develop through childhood, puberty and adolescence is vital since it holds key information regarding current and future health. Our study aimed to determine how BM, LM and FM track from prepuberty to early adulthood in girls and what factors are associated with intra- and inter-individual variation in these three tissues. Methods The study was a 7-year longitudinal cohort study. BM, LM and FM measured using dual-energy X-ray absorptiometry, self-reported dietary information, leisure time physical activity (LTPA) and other factors were assessed one to eight times in 396 girls aged 10 to 13 years (baseline), and in 2…
Risk of low bone mineral density and low body mass index in patients with non-celiac wheat-sensitivity: a prospective observation study.
2014
Background Non-celiac gluten sensitivity (NCGS) or ‘wheat sensitivity’ (NCWS) is included in the spectrum of gluten-related disorders. No data are available on the prevalence of low bone mass density (BMD) in NCWS. Our study aims to evaluate the prevalence of low BMD in NCWS patients and search for correlations with other clinical characteristics. Methods This prospective observation study included 75 NCWS patients (63 women; median age 36 years) with irritable bowel syndrome (IBS)-like symptoms, 65 IBS and 50 celiac controls. Patients were recruited at two Internal Medicine Departments. Elimination diet and double-blind placebo controlled (DBPC) wheat challenge proved the NCWS diagnosis. A…
Differences in Corneal Anatomy in a Pair of Monozygotic Twins Due to Continuous Contact Lens Wear
2003
Purpose To study the differences in the corneal anatomy in a pair of 31-year-old monozygotic female twins, one of whom has been a contact lens wearer for the past 15 years and the other is a nonwearer. Methods We analyzed the corneal thickness and the corneal endothelial cell density of the monozygotic twins and of two age-matched control groups, one made up of non-contact lens wearers (35 eyes of 35 patients; mean age, 29.32 +/- 2.83 years) and the other made up of soft contact lens wearers (30 eyes of 30 patients; mean age, 33.08 +/- 3.72 years; mean duration of contact lens use, 10.62 +/- 4.32 years). Five corneal thickness measurements were carried out with the Orbscan Topography System…
Differential Effects of Exercise on Tibial Shaft Marrow Density in Young Female Athletes
2013
Increased mechanical loading can promote the preferential differentiation of bone marrow mesenchymal stem cells to osteoblastogenesis, but it is not known whether long-term bone strength-enhancing exercise in humans can reduce marrow adiposity.Our objective was to examine whether bone marrow density (MaD), as an estimate of marrow adiposity 1) differs between young female athletes with contrasting loading histories and bone strengths and 2) is an independent predictor of bone strength at the weight-bearing tibia.Mid-tibial MaD, cortical area (CoA), total area, medullary area, strength strain index (SSI), and cortical volumetric bone mineral density (vBMD) (total, endocortical, midcortical, …
Bone’s Structural Diversity in Adult Females Is Established before Puberty
2009
Bone must be rigid for leverage yet light for mobility. We studied how bone modeling and remodeling fashioned differences in bone size, shape, and mass during growth to achieve these properties in adulthood.We measured the structural features of a tibial cross-section using quantitative computed tomography and markers of remodeling in 258 10- to 13-yr-old girls during 2 yr and in 108 of their mothers.Tibia total cross-sectional area and mass correlated between daughters and their mothers (r = 0.34 and 0.44, respectively, both P0.01). The location of a daughter's tibial total cross-sectional area, medullar area, and bone mass in the lower, middle, or upper part of the sample distribution was…
Nephrolithiasis, bone mineral density, osteoporosis, and fractures: a systematic review and comparative meta-analysis
2016
Summary: Our meta-analysis demonstrates that people with nephrolithiasis have decreased bone mineral density, an increased odds of osteoporosis, and potentially an elevated risk of fractures. Introduction: People with nephrolithiasis might be at risk of reduced bone mineral density (BMD) and fractures, but the data is equivocal. We conducted a meta-analysis to investigate if patients with nephrolithiasis have worse bone health outcomes (BMD), osteoporosis, and fractures versus healthy controls (HCs). Methods: Two investigators searched major databases for articles reporting BMD (expressed as g/cm2 or a T- or Z-score), osteoporosis or fractures in a sample of people with nephrolithiasis, and…
Hypogonadism and Hormone Replacement Therapy on Bone Mass of Adult Women with Thalassemia Major
2002
We studied bone mass and metabolism in 30 adult women (age 28.5 +/- 1.3) with thalassemia major (TM) and evaluated whether prolonged hormone replacement therapy (HRT) was able to optimize bone accrual. TM patients had reduced bone mass, increased bone turnover and lower serum gonadotropin and estradiol levels compared with 10 normal women of similar age. A significant correlation was found between bone mass and sex hormone levels. Six TM patients with normal ovarian function had normal bone turnover markers and modestly low bone mass (lumbar spine -1.29 +/- 0.31; femoral neck -0.60+/-0.21; Z-score). The other 24 TM women were hypogonadic and had significantly lower bone mass for age (lumbar…
Collagen copolymer posterior chamber phakic intraocular lens for hyperopia correction: three-year follow-up.
2013
Purpose To assess the efficacy, predictability, safety, and stability of the Visian V3 Implantable Collamer Lens posterior chamber phakic intraocular lens (PC pIOL) for moderate to high hyperopia. Setting Private clinic, Oviedo, Spain. Design Prospective nonrandomized clinical study. Methods The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, endothelial cell density, intraocular pressure (IOP), central vault, and adverse events were evaluated for 3 years postoperatively. Results The study comprised 73 eyes of 44 patients. The mean spherical equivalent decreased from +4.84 diopters (D) ± 1.6 (SD) (range +1.00 to +7.75 D) preoperatively to −0.13 ± 0.39 …