bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel methods to evaluate fracture risk models
Authors: Donaldson Meghan G , Cawthon Peggy M , Schousboe John T , Ensrud Kristine E , Lui Li-Yung , Cauley Jane A , Hillier Teresa A , Taylor Brent C , Hochberg Marc C , Bauer Douglas C , Cummings Steven R ,   for the Study of Osteoporotic Fractures (SOF)
Published: February 2011

Fracture prediction models help to identify individuals at high risk who may benefit from treatment. Area under the curve (AUC) is used to compare prediction models. However, the AUC has limitations and may miss important differences between models. Novel reclassification methods quantify how accurately models classify patients who benefit from treatment and the proportion of patients above/below treatment thresholds. We applied two reclassification methods, using the National Osteoporosis Foundation (NOF) treatment thresholds, to compare two risk models: femoral neck bone mineral density (BMD) and age (simple model) and FRAX (FRAX model). The Pepe method classifies based on case/noncase status and examines the proportion of each above and below thresholds. The Cook method examines fracture rates above and below thresholds. We applied these to the Study of Osteoporotic Fractures (SOF). There were 6036 (1037 fractures) and 6232 (389 fractures) participants with complete data for major osteoporotic and hip fracture, respectively. Both models for major osteoporotic fracture (0.68 versus 0.69) and hip fracture (0.75 versus 0.76) had similar AUCs. In contrast, using reclassification methods, each model classified a substantial number of women differently. Using the Pepe method, the FRAX model (versus the simple model) missed treating 70 (7%) cases of major osteoporotic fracture but avoided treating 285 (6%) noncases. For hip fracture, the FRAX model missed treating 31 (8%) cases but avoided treating 1026 (18%) noncases. The Cook method (both models, both fracture outcomes) had similar fracture rates above/below the treatment thresholds. Compared with the AUC, new methods provide more detailed information about how models classify patients. © 2011 American Society for Bone and Mineral Research
WHO absolute fracture risk models (FRAX): Do clinical risk factors improve fracture prediction in older women without osteoporosis?
Authors: Hillier Teresa A , Cauley Jane A , Rizzo Joanne H , Pedula Kathryn L , Ensrud Kristine E , Bauer Douglas C , Lui Li-Yung , Vesco Kimberly K , Black Dennis M , Donaldson Meghan G , LeBlanc Erin S , Cummings Steven R
Published: February 2011

Bone mineral density (BMD) is a strong predictor of fracture, yet most fractures occur in women without osteoporosis by BMD criteria. To improve fracture risk prediction, the World Health Organization recently developed a country-specific fracture risk index of clinical risk factors (FRAX) that estimates 10-year probabilities of hip and major osteoporotic fracture. Within differing baseline BMD categories, we evaluated 6252 women aged 65 or older in the Study of Osteoporotic Fractures using FRAX 10-year probabilities of hip and major osteoporotic fracture (ie, hip, clinical spine, wrist, and humerus) compared with incidence of fractures over 10 years of follow-up. Overall ability of FRAX to predict fracture risk based on initial BMD T-score categories (normal, low bone mass, and osteoporosis) was evaluated with receiver-operating-characteristic (ROC) analyses using area under the curve (AUC). Over 10 years of follow-up, 368 women incurred a hip fracture, and 1011 a major osteoporotic fracture. Women with low bone mass represented the majority (n = 3791, 61%); they developed many hip (n = 176, 48%) and major osteoporotic fractures (n = 569, 56%). Among women with normal and low bone mass, FRAX (including BMD) was an overall better predictor of hip fracture risk (AUC = 0.78 and 0.70, respectively) than major osteoporotic fractures (AUC = 0.64 and 0.62). Simpler models (eg, age + prior fracture) had similar AUCs to FRAX, including among women for whom primary prevention is sought (no prior fracture or osteoporosis by BMD). The FRAX and simpler models predict 10-year risk of incident hip and major osteoporotic fractures in older US women with normal or low bone mass. © 2011 American Society for Bone and Mineral Research
Chlorthalidone improves vertebral bone quality in genetic hypercalciuric stone-forming rats
Authors: Bushinsky David A , Willett Thomas , Asplin John R , Culbertson Christopher , Che Sara PY , Grynpas Marc
Published: February 2011

We have bred a strain of rats to maximize urine (u) calcium (Ca) excretion and model hypercalciuric nephrolithiasis. These genetic hypercalciuric stone-forming (GHS) rats excrete more uCa than control Sprague-Dawley rats, uniformly form kidney stones, and similar to patients, demonstrate lower bone mineral density. Clinically, thiazide diuretics reduce uCa and prevent stone formation; however, whether they benefit bone is not clear. We used GHS rats to test the hypothesis that the thiazide diuretic chlorthalidone (CTD) would have a favorable effect on bone density and quality. Twenty GHS rats received a fixed amount of a 1.2% Ca diet, and half also were fed CTD (4 to 5 mg/kg/d). Rats fed CTD had a marked reduction in uCa. The axial and appendicular skeletons were studied. An increase in trabecular mineralization was observed with CTD compared with controls. CTD also improved the architecture of trabecular bone. Using micro–computed tomography (µCT), trabecular bone volume (BV/TV), trabecular thickness, and trabecular number were increased with CTD. A significant increase in trabecular thickness with CTD was confirmed by static histomorphometry. CTD also improved the connectivity of trabecular bone. Significant improvements in vertebral strength and stiffness were measured by vertebral compression. Conversely, a slight loss of bending strength was detected in the femoral diaphysis with CTD. Thus results obtained in hypercalciuric rats suggest that CTD can favorably influence vertebral fracture risk. CTD did not alter formation parameters, suggesting that the improved vertebral bone strength was due to decreased bone resorption and retention of bone structure. © 2011 American Society for Bone and Mineral Research
Post–hip fracture use of prescribed calcium plus vitamin D or vitamin D supplements and antiosteoporotic drugs is associated with lower mortality: A nationwide study in Finland
Authors: Nurmi-Lüthje Ilona , Sund Reijo , Juntunen Merja , Lüthje Peter
Published: February 2011

We previously found a positive association between calcium plus vitamin D and antiosteoporotic drugs and survival among hip fracture patients. Our aim was to verify this observation using a nationwide database. A retrospective cohort of home-discharged hip fracture patients aged 50 years or older (n = 23,615) was enrolled from the national database. Primary exposure was medical treatment for osteoporosis, and the outcome was all-cause mortality. Cumulative mortalities were calculated using the Kaplan-Meier estimator. The relationship between mortality and medication purchases was modeled using Cox's proportional hazards regression with time-dependent covariates for medication use. One in 4 women and 1 in 10 men with a hip fracture were treated for osteoporosis in Finland. Unadjusted 1-year mortality was lower among patients who purchased calcium plus vitamin D or vitamin D supplements and antiosteoporotic drugs than among those who did not purchase these medications [hazard ratio (HR) = 0.74, 95% confidence interval (CI) 0.67–0.81]. The difference in unadjusted cumulative mortality remained in favor of the drug users for at least 5 years. Among men, the use of calcium plus vitamin D or vitamin D supplements was associated with lower 1-year mortality even after adjustments for observed confounders (HR = 0.74, 95% CI 0.56–0.97). Among women, the use of antiosteoporotic drugs was associated with lower mortality (HR = 0.79, 95% CI 0.67–0.93). There was a tendency to even better survival in both genders if calcium plus vitamin D or vitamin D supplements and antiosteoporotic drugs were used simultaneously, the HR being 0.72 (95% CI 0.50–1.03) in men and 0.62 (95% CI 0.50–0.76) in women. © 2011 American Society for Bone and Mineral Research
Levels of serotonin, sclerostin, bone turnover markers as well as bone density and microarchitecture in patients with high-bone-mass phenotype due to a mutation in Lrp5
Authors: Frost Morten , Andersen Tom , Gossiel Fatma , Hansen Stinus , Bollerslev Jens , van Hul Wim , Eastell Richard , Kassem Moustapha , Brixen Kim
Published: February 2011

Patients with an activation mutation of the Lrp5 gene exhibit high bone mass (HBM). Limited information is available regarding compartment-specific changes in bone. The relationship between the phenotype and serum serotonin is not well documented. To evaluate bone, serotonin, and bone turnover markers (BTM) in Lrp5-HBM patients, we studied 19 Lrp5-HBM patients (T253I) and 19 age- and sex-matched controls. DXA and HR-pQCT were used to assess BMD and bone structure. Serum serotonin, sclerostin, dickkopf-related protein 1 (DKK1), and BTM were evaluated. Z-scores for the forearm, total hip, lumbar spine, forearm, and whole body were significantly increased (mean ± SD) between 4.94 ± 1.45 and 7.52 ± 1.99 in cases versus −0.19 ± 1.19 to 0.58 ± 0.84 in controls. Tibial and radial cortical areas, thicknesses, and BMD were significantly higher in cases. In cases, BMD at the lumbar spine and forearm and cortical thickness were positively associated and trabecular area negatively associated with age (r = 0.49, 0.57, 0.74, and −0.61, respectively, p < .05). Serotonin was lowest in cases (69.5 [29.9–110.4] ng/mL versus 119.4 [62.3–231.0] ng/mL, p < .001) and inversely associated with tibial cortical density (r = −0.49, p < .05) and directly with osteocalcin (OC), bone-specific alkaline phosphatase (B-ALP), and procollagen type 1 amino-terminal propeptide (PINP) (r = 0.52–0.65, p < .05) in controls only. OC and S-CTX were lower and sclerostin higher in cases, whereas B-ALP, PINP, tartrate-resistant acid phosphatase (TRAP), and dickkopf-related protein 1 (DKK1) were similar in cases and controls. In conclusion, increased bone mass in Lrp5-HBM patients seems to be caused primarily by changes in trabecular and cortical bone mass and structure. The phenotype appeared to progress with age, but BTM did not suggest increased bone formation. © 2011 American Society for Bone and Mineral Research
Better skeletal microstructure confers greater mechanical advantages in Chinese-American women versus white women
Authors: Liu X Sherry , Walker Marcella D , McMahon Donald J , Udesky Julia , Liu George , Bilezikian John P , Guo X Edward
Published: February 2011

Despite lower areal bone mineral density (aBMD), Chinese-American women have fewer fractures than white women. We hypothesized that better skeletal microstructure in Chinese-American women in part could account for this paradox. Individual trabecula segmentation (ITS), a novel image-analysis technique, and micro–finite-element analysis (µFEA) were applied to high-resolution peripheral quantitative computed tomography (HR-pQCT) images to determine bone microarchitecture and strength in premenopausal Chinese-American and white women. Chinese-American women had 95% and 80% higher plate bone volume fraction at the distal radius and tibia, respectively, as well as 20% and 18% higher plate number density compared with white women (p < .001). With similar rodlike characteristics, the plate-to-rod ratio was twice as high in the Chinese-American than in white trabecular bone (p < .001). Plate-rod junction density, a parameter indicating trabecular network connections, was 37% and 29% greater at the distal radius and tibia, respectively, in Chinese-American women (p < .002). Moreover, the orientation of the trabecular bone network was more axially aligned in Chinese-American women because axial bone volume fraction was 51% and 32% higher at the distal radius and tibia, respectively, than in white women (p < .001). These striking differences in trabecular bone microstructure translated into 55% to 68% (distal radius, p < .001) and 29% to 43% (distal tibia, p < .01) greater trabecular bone strength, as assessed by Young's moduli, in the Chinese-American versus the white group. The observation that Chinese-American women have a major microstructural advantage over white women may help to explain why their risk of fracture is lower despite their lower BMD. © 2011 American Society for Bone and Mineral Research
Vibrational spectral signatures of peptide secondary structures: N‐methylation and side chain hydrogen bond in cyclosporin A
Authors: Qu Zheng‐Wang , Zhu Hui , May Volkhard
Published: February 2011

Molecular dynamics simulations are performed to explore important conformations of cyclosporin A, an immunosuppressive cyclic undecapeptide drug, in different media including gas‐phase, chloroform, and acetonitrile. Density functional theory calculations are used to refine the low‐lying conformers and to predict their infrared and vibrational circular dichroism spectra. Vibrational spectral signatures in the important amide II, I, and A regions are identified for typical peptide secondary structures including β‐turn (type II′ or I), antiparallel β‐sheet (flat or twisted), inverse γ‐turn, N‐methylated peptide bond, and side chain H‐bond. New insights into the spectral signatures of secondary structures especially with N‐methylation and side chain hydrogen bond are provided, which can be very useful for further peptide conformation analysis in general. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
The finite‐size effect on the transport properties in edge‐modified graphene nanoribbon‐based molecular devices
Authors: Ding Zongling , Jiang Jun , Xing Huaizhong , Shu Haibo , Huang Yan , Chen Xiaoshuang , Lu Wei
Published: February 2011

The size‐dependence on the electronic and transport properties of the molecular devices of the edge‐modified graphene nanoribbon (GNR) slices is investigated using density‐functional theory and Green's function theory. Two edge‐modifying functional group pairs are considered. Energy gap is found in all the GNR slices. The gap shows an exponential decrease with increasing the slice size of two vertical orientations in the two edge terminated cases, respectively. The tunneling probability and the number of conducting channel decreases with increasing the GNR‐slices size in the junctions. The results indicate that the acceptor‐donor pair edge modulation can improve the quantum conductance and decrease the finite‐size effect on the transmission capability of the GNR slice‐based molecular devices.
Assessment of hoarding
Authors: Frost Randy O. , Hristova Veselina
Published: February 2011

Various questionnaires and interviews have been created over the years to assess compulsive hoarding. In this article, we summarize existing measures, offer practice‐friendly suggestions for assessment of hoarding, and address frequent problems in its clinical evaluation. Existing measures for hoarding can be divided into those that are subscales of general measures of obsessive‐compulsive disorder (e.g., Obsessive‐Compulsive Inventory and Yale‐Brown Obsessive‐Compulsive Scale) and those that were developed specifically for hoarding and related phenomena. The former were largely developed without the benefit of research identifying the nature of hoarding, while the latter capture the specific dimensions of hoarding and are recommended for clinical use. We provide a case illustration and additional clinical considerations in the assessment of hoarding as well. © 2011 Wiley Periodicals, Inc. J Clin Psychol: In Session 67:1–11, 2011.
Neuropsychological and neural correlates of hoarding: a practice‐friendly review
Authors: Mataix‐Cols David , Pertusa Alberto , Snowdon John
Published: February 2011

Hoarding can be a symptom of multiple neurological and psychiatric disorders, including obsessive‐compulsive disorder (OCD). Recent evidence suggests that, in many cases, hoarding can also be a standalone problem that presents independently from other conditions; this has led to the proposal of a new diagnostic entity named hoarding disorder. This article reviews the neuropsychological and neuroimaging research on pathological hoarding. Most research in humans has been conducted in the context of individuals with brain damage, dementia, or OCD. Studies of well‐characterized samples of individuals with hoarding disorder are extremely rare. Although not possible to establish firm conclusions at this stage, we conclude with a series of observations and recommendations for clinical practice. © 2011 Wiley Periodicals, Inc. J Clin Psychol: In Session 67:1–10, 2011.
Cognitive‐behavioral therapy for hoarding in the context of contamination fears
Authors: Steketee Gail , Tolin David F.
Published: February 2011

Difficulty discarding and excessive acquiring can be treated using specialized cognitive‐behavioral treatment that includes motivational interviewing, skills training, practice sorting and discarding, and cognitive restructuring. Early psychotherapy efforts to treat hoarding have proved less effective than this combination of methods targeted at the characteristic features of hoarding. Treatment strategies are illustrated through a case example of a woman struggling with both hoarding and contamination concerns. © 2011 Wiley Periodicals, Inc. J Clin Psychol: In Session 67:1–12, 2011.
Primary cilia regulates the directional migration and barrier integrity of endothelial cells through the modulation of Hsp27 dependent actin cytoskeletal organization
Authors: Jones Thomas J. , Adapala Ravi K. , Geldenhuys Werner J. , Bursley Chris , AbouAlaiwi Wissam A. , Nauli Surya M. , Thodeti Charles K.
Published: February 2011

Cilia are mechanosensing organelles that communicate extracellular signals into intracellular responses. Altered functions of primary cilia play a key role in the development of various diseases including polycystic kidney disease. Here, we show that endothelial cells from the oak ridge polycystic kidney (Tg737orpk/orpk) mouse, with impaired cilia assembly, exhibit a reduction in the actin stress fibers and focal adhesions compared to wild‐type (WT). In contrast, endothelial cells from polycystin‐1 deficient mice (pkd1null/null), with impaired cilia function, display robust stress fibers, and focal adhesion assembly. We found that the Tg737orpk/orpk cells exhibit impaired directional migration and endothelial cell monolayer permeability compared to the WT and pkd1null/null cells. Finally, we found that the expression of heat shock protein 27 (hsp27) and the phosphorylation of focal adhesion kinase (FAK) are downregulated in the Tg737orpk/orpk cells and overexpression of hsp27 restored both FAK phosphorylation and cell migration. Taken together, these results demonstrate that disruption of the primary cilia structure or function compromises the endothelium through the suppression of hsp27 dependent actin organization and focal adhesion formation, which may contribute to the vascular dysfunction in ciliopathies. J. Cell. Physiol. 227: 70–76, 2012. © 2011 Wiley Periodicals, Inc.
The connexin mimetic peptide Gap27 increases human dermal fibroblast migration in hyperglycemic and hyperinsulinemic conditions in vitro
Authors: Wright Catherine S. , Pollok Simone , Flint David J. , Brandner Johanna M. , Martin Patricia E.M.
Published: February 2011

Significant increases in skin wound healing rates occur by reducing connexin‐mediated communication (CMC). Gap27, a connexin (Cx) mimetic peptide targeted to the second extracellular loop of Cx43, which inhibits CMC, increases migration of human keratinocytes and dermal fibroblasts. To examine the efficacy of Gap27 in a hyperglycemic and hyperinsulinemic in vitro environment, cell migration, gap junction, and Cx hemichannel functionality and cell–substrate adhesion assays were performed on human dermal fibroblasts and diabetic fibroblast and keratinocytes. To investigate fibroblast genes involved in these processes, extra‐cellular matrix (ECM) and adhesion gene expression was determined with a PCR array. Gap27 increased fibroblast migration in both euglycemia/euinsulinemia and hyperglycemia/hyperinsulinemia, and influenced migration in diabetic keratinocytes. Hyperglycemia/hyperinsulinemia reduced gap junction coupling in fibroblasts and Gap27 reduced CMC and cell adhesion to substrata in fibroblasts cultured in high glucose. Migrating dermal fibroblast ECM and cell adhesion genes were found to be differentially regulated by Gap27 in euglycemia and hyperglycemia. The PCR array showed that Gap27 upregulated 34 genes and downregulated 1 gene in euglycemic migrating fibroblasts. By contrast in hyperglycemia, Gap27 upregulated 1 gene and downregulated 9 genes. In euglycemic conditions, Gap27 induced upregulation of genes associated with ECM remodeling, whereas in hyperglycemia, ECM component genes were downregulated by Gap27. Thus, Gap27 improves cell migration during scrape‐wound repair in hyperglycemia/hyperinsulinemia conditions in vitro, although migration of diabetic cells is less influenced. Our results suggest that this increase in motility may occur by decreasing gap junction and hemichannel activity and altering gene expression in the adhesion and ECM pathway. J. Cell. Physiol. 227: 77–87, 2012. © 2011 Wiley Periodicals, Inc.
Biodiesel production from Stichococcus strains at laboratory scale
Authors: Olivieri Giuseppe , Marzocchella Antonio , Andreozzi Roberto , Pinto Gabriele , Pollio Antonino
Published: February 2011

BACKGROUND: This paper reports the results of an experimental campaign of autotrophic cultures of Stichococcus strains aiming at selecting the most promising strain for biofuel production. The strain selected—S. bacillaris 158/11—was cultivated in 1 L lab‐scale bubble column photobioreactors under fed‐batch and semi‐continuous conditions. A Bold basal medium supplemented with NaNO3 as nitrogen source was adopted. Tests were carried out at 23 °C, 140 µE m−2 s−1, and air flow rate ranging between 0.4 and 4 vvm. Cultures were characterized in terms of pH, concentration of total nitrogen, total organic carbon, total inorganic carbon, biomass, lipid fraction and methyl‐ester distribution of transesterified lipids.

RESULTS: S. bacillaris 158/11 proved to be the best strain to produce biodiesel. Methyl‐ester distribution was characterized by a large fraction of methyl palmitate, methyl linolenate, methyl linoleate, and methyl oleate along with phytol. The process photosynthetic efficiency—fraction of available light stored as chemical energy ‐ was about 1.5%. Specific biomass productivity was ∼60 mgDM L−1 day−1 under the semi‐continuous conditions tested. Total lipid productivity was 14 mg L−1 day−1 at a dilution rate of 0.050 L day−1.

CONCLUSION: S. bacillaris 158/11 is a potential strain for massive microalgae cultures for biofuel production. Higher biomass/total‐lipid productivity could be obtained in sunlight. Copyright © 2011 Society of Chemical Industry
Variation of the specific surface area and porosity of anhydrous zinc oxalate with water vapour pressure
Authors: Mikhail Raouf Sh. , Guindy Nabila M. , Ali Ismail T.
Published: February 2011

Specific surface areas and pore structure studies were carried out on two sets of samples of anhydrous zinc oxalate prepared from the dihydrate by heating at 130 and 180°C in various atmospheres of differing water vapour pressure. The two sets of samples were freshly prepared and aged samples. The variation of specific surface areas with water vapour pressure was found to behave in accordance with the Smith‐Topley effect, with a minimum SBET value located at 3.0 mmHg of water vapour. Analysis of the nitrogen adsorption isotherms by the t‐method revealed the existence of both micropores and mesopores in the freshly prepared samples heated both at 130 and 180°C in 8.0 mmHg water vapour, and also in the aged samples prepared at 130°C in vacuo, and at 180°C in 8.0 mmHg water vapour. The rest of the samples possess only wide pores. Complete pore structure analysis for both micro‐ and mesopores was carried out for all samples investigated, and an attempt was made to correlate the factors affecting the development of surface area and pore structure, both in the presence and absence of water vapour, with those affecting the dehydration rate, and which occasionally lead to the Smith‐Topley effect.
Recovery of boric acid from ulexite by leaching with hydrochloric acid derived from waste chlorine gas and froth flotation
Authors: Yarar Baki
Published: February 2011

A process for producing boric acid from ulexite and the recovery of the product by flotation is described. It was found that the degree of conversion of ulexite to boric acid decreased with rising HCl concentration. The undissolved mineral, together with other impurities such as clays, could be depressed by Quebracho, Orzan‐S, Daxad‐23 or starch, the first two being more effective. Concentrates assaying 97.1% H3BO3 were obtained without resorting to recrystallisation of the product. No flotation reagents other than the above‐mentioned were necessary for the process.
Diurnal dynamics of S‐phase entry of germ cells in the secondary testis of the bambooleaf wrasse (Pseudolabrus sieboldi)
Authors: Kitano Hajime , Irie Susumu , Yamaguchi Akihiko , Matsuyama Michiya
Published: February 2011

The diversity of reproductive strategies found in fish is attributed to the adaptation of gametogenesis to different habitats. To date, however, information about the dynamics of male gametogenesis and its molecular mechanisms of control by the brain–pituitary–gonadal (BPG) axis, a well‐known facet of the endocrine system in vertebrates, is not sufficient to explain the variation in spawning and regulatory mechanisms among species. The bambooleaf wrasse (Pseudolabrus sieboldi) is a protogynous hermaphrodite fish that shows clear diurnal fluctuations in gonadotropin gene expression and serum sex steroid levels associated with spawning. In this study, morphometrical and histological analyses were performed to determine the number of spermatogonial generations in the testis of the sex‐changed male (secondary testis). In addition, the diurnal dynamics of S‐phase entry of germ cells was explored by measuring the frequency of BrdU‐incorporating germ cells at different times of day. We found that the bambooleaf wrasse spermatozoa were generated through nine spermatogonial generations, followed by meiotic divisions accompanied by loss of some spermatocytes and spermatids through apoptosis. BrdU analyses revealed a high frequency of entry into S‐phase of undifferentiated type A spermatogonia at 03:00 hr. On the other hand, the frequency of spermatocytes at S‐phase of the cell cycle decreased during 00:00–09:00 hr. This study demonstrates for the first time the daily fluctuations of S‐phase entry of male germ cells in fish. These results will provide a useful foundation for understanding the roles of endocrinological and cytological regulation of fish spermatogenesis.J. Exp. Zool. 315A:232–241, 2011. © 2011 Wiley‐Liss, Inc.
Quantitative analysis of sperm plane circular movement in the blue mussels Mytilus edulis, M. trossulus and their hybrids
Authors: Liu Guangxu , Innes David , Thompson Raymond J.
Published: February 2011

Fertilization success of free spawning organisms such as Mytilus species depends on gamete interactions. Therefore, gamete traits such as sperm movement are important for determining fertilization success in free spawning organisms. Since little is known about sperm movement pattern in Mytilus species, the purpose of this study was to investigate sperm movement pattern of blue mussel M. edulis, M. trossulus and their hybrids using computer‐assisted sperm movement video analysis. Sperm of all genotypes were found to conduct circular movement in a two‐dimensional plane. Furthermore, new sperm movement parameters, real time radius (R), angle change rate (θ) and the center of circular track (Ot) were developed to verify and quantitatively describe the plane circular movement pattern using software (Image‐J) that may be widely applied to sperm movement study in other organisms. Angle change rate was positively correlated to fertilization success. However, no correlation between fertilization and real time radius was detected. Although no interspecific differences were found in the radius, the F1 (first generation) hybrid sperm had a lower angle change rate than M. edulis and M. trossulus. Published studies have shown that sperm circular movement is more prevalent in aquatic broadcast spawning species than in species with mating behavior or internal fertilization. Therefore, a two‐dimensional circular movement pattern in sperm may represent a trait that increases fertilization success for broadcast spawning species by either increasing gamete interaction rate at a small scale and/or avoiding swimming further away from the eggs before sperm detects the chemoattractant gradient. J. Exp. Zool. 315:280–290, 2011. © 2011 Wiley‐Liss, Inc.
Cytosine, the double helix and DNA self‐assembly
Authors: Timsit Youri , Varnai Peter
Published: February 2011

DNA self‐assembly has crucial implications in reading out the genetic information in the cell and in nanotechnological applications. In a recent paper, self‐assembled DNA crystals displaying spectacular triangular motifs have been described (Zheng et al., 2009). The authors claimed that their data demonstrate the possibility to rationally design well‐ordered macromolecular 3D DNA lattice with precise spatial control using sticky ends. However, the authors did not recognize the fundamental features that control DNA self‐assembly in the lateral direction. By analysing available crystallographic data and simulating a DNA triangle, we show that the double helix geometry, sequence‐specific cytosine–phosphate interactions and divalent cations are in fact responsible for the precise spatial assembly of DNA. Copyright © 2011 John Wiley & Sons, Ltd.
Looking at the proteases from a simple perspective
Authors: Castro Helena C. , Abreu Paula A. , Geraldo Reinaldo B. , Martins Rita C.A. , dos Santos Ruben , Loureiro Natália I.V. , Cabral Lúcio M. , Rodrigues Carlos R.
Published: February 2011

Proteases have received enormous interest from the research and medical communities because of their significant roles in several human diseases. Some examples include the involvement of thrombin in thrombosis, HIV‐1 protease in Acquired Immune Deficiency Syndrome, cruzain in Trypanosoma cruzi infection, and membrane‐type 1 matrix metalloproteinase in tumor invasion and metastasis. Many efforts has been undertaken to design effective inhibitors featuring potent inhibitory activity, specificity, and metabolic stability to those proteases involved in such pathologies. Protease inhibitors usually target the active site, but some of them act by other inhibitory mechanisms. The understanding of the structure‐function relationships of proteases and inhibitors has an impact on new inhibitor drugs designing. In this paper, the structures of four proteases (thrombin, HIV‐protease, cruzain, and a matrix metalloproteinase) are briefly reviewed, and used as examples of the importance of proteases for the development of new treatment strategies, leading to a longer and healthier life. Copyright © 2011 John Wiley & Sons, Ltd.
Hemodynamic aspects of mitral regurgitation assessed by generalized phase‐contrast MRI
Authors: Dyverfeldt Petter , Kvitting John‐Peder Escobar , Carlhäll Carl Johan , Boano Gabriella , Sigfridsson Andreas , Hermansson Ulf , Bolger Ann F. , Engvall Jan , Ebbers Tino
Published: February 2011

Purpose:

To investigate the utility of MRI measurement of left atrial (LA) flow patterns and turbulent kinetic energy (TKE) in patients with clinically significant mitral regurgitation.

Materials and Methods:

Three‐dimensional cine phase‐contrast MRI (PC‐MRI) data were acquired in five patients with posterior mitral leaflet prolapse and two normal volunteers. LA flow patterns were assessed using particle trace visualization. Specifically, vortices were recognized by closed streamlines. LA flow distortion was assessed by estimation of TKE. In addition, the regurgitant volume was measured.

Results:

Four of the mitral regurgitation patients had eccentric regurgitant jets directed toward the septum; one patient had a central jet. The dominant systolic vortex was located in proximity to the regurgitant jet. The LA flow was highly disturbed with elevated values of TKE; peak LA TKE ranged from 13 to 37 mJ and occurred consistently at late systole. The average LA TKE per cardiac cycle was significantly related to the regurgitant volume (TKE = 0.573 + 0.179·RegVol, R2 = 0.983).

Conclusion:

MRI permits investigations of atrial flow patterns and TKE in significant mitral regurgitation. The degree of LA flow distortion, as measured by the average LA TKE over one cardiac cycle, appears to reflect the severity of regurgitation. J. Magn. Reson. Imaging 2011;33:582–588. © 2011 Wiley‐Liss, Inc.
Active Crohn's Disease in the small bowel: Evaluation by diffusion weighted imaging and quantitative dynamic contrast enhanced MR imaging
Authors: Oto Aytekin , Kayhan Arda , Williams Joshua T.B. , Fan Xiaobing , Yun Laura , Arkani Sanaz , Rubin David T.
Published: February 2011

Purpose

To determine relative diagnostic value of MR diffusion and perfusion parameters in detection of active small bowel inflammation in patients with Crohn's disease (CD).

Materials and Methods

We reviewed 18 patients with active CD of terminal ileum (TI) who underwent MR enterography (MRE; including dynamic contrast enhanced MRI and diffusion‐weighted MRI). Conventional MRI findings of TI were recorded. Regions of interest were drawn over TI and normal ileum to calculate apparent diffusion coefficient (ADC), the volume transfer constant (Ktrans) and the contrast media distribution volume (ve). Receiver operating characteristic analysis was used to determine their diagnostic performance.

Results

Among conventional MR findings, mural thickening and increased enhancement were present in all actively inflamed small bowel. Ktrans, ve, and ADC values differed significantly between actively inflamed TI and normal ileum (0.92 s−1 versus 0.36 s−1; 0.31 versus 0.15 ± 0.08; 0.00198 mm2/s versus 0.00311 mm2/s; P < 0.001). Area under the curve (AUC) for Ktrans, ve, and ADC values ranged from 0.88 to 0.92 for detection of active inflammation. Combining Ktrans and ADC data provided an AUC value of 0.95.

Conclusion

Dynamic contrast‐enhanced MRI (DCE‐MRI) and diffusion‐weighted imaging (DWI) provide quantitative measures of small bowel inflammation that can differentiate actively inflamed small bowel segments from normal small bowel in CD. DWI provides better sensitivity compared with DCE‐MRI and combination of ADC and Ktrans parameters for analysis can potentially improve specificity. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.
Diffusion‐weighted imaging for prediction of volumetric response of leiomyomas following uterine artery embolization: A preliminary study
Authors: Hecht Elizabeth M. , Do Richard K.G. , Kang Stella K. , Bennett Genevieve L. , Babb James S. , Clark Timothy W.I.
Published: February 2011

Purpose

To determine if pretreatment apparent diffusion coefficient (ADC) of leiomyomas could predict volumetric response (VR) following uterine artery embolization (UAE).

Materials and Methods

We retrospectively studied 11 women who underwent pelvic MRI before and >120 days following UAE. MRI included conventional and diffusion weighted imaging sequences. Percentage change in leiomyoma volume was determined by multiplanar T2‐weighted imaging. A Pearson correlation coefficient was calculated between leiomyoma VR following UAE and the following pre‐embolization parameters: initial volume, relative enhancement, relative T2 signal intensity (SI) and ADC. Receiver operating characteristic (ROC) curve analysis was used to determine the sensitivity and specificity of ADC for predicting volumetric response.

Results

Twenty‐eight leiomyomas were included with a mean interval from UAE to follow‐up MRI of 207 days. The preprocedural volume of the leiomyomas ranged from 18 to 182 cm3 (median 47 cm3). and ADC ranged from 0.37 to 1.71 mm2/s (mean 0.80 mm2/s). All leiomyomas were 100% necrotic following UAE. Leiomyoma VR following UAE was 48% ± 3.5%. with significant correlation between VR and ADC (r = 0.41; P = 0.017) but no correlation with initial leiomyoma volume, relative T2 SI, or relative enhancement. Using a threshold of 0.875 × 10−3 mm2/s, ADC could predict > 50% VR with sensitivity and specificity of 70% and 83%, respectively.

Conclusion

Pre‐UAE ADC of leiomyomas correlated significantly with percent VR following UAE. In contrast, no correlation was seen between VR post‐UAE and conventional imaging findings. This suggests that VR following UAE depends on leiomyoma histology reflected in DWI rather than features revealed by conventional MRI. J. Magn. Reson. Imaging 2011;33:641–646. © 2011 Wiley‐Liss, Inc.
Pediatric magnetic resonance urography
Authors: Jones Richard A. , Grattan‐Smith J. Damien , Little Stephen
Published: February 2011

Magnetic resonance urography (MRU) is a powerful clinical tool that fuses anatomic information with functional data in a single test without the use of ionizing radiation. This article provides an overview of the technical aspects, as well as common clinical applications with an emphasis on the evaluation of hydronephrosis. A fluid challenge is an essential part of our MRU protocol and enables the definition of compensated or decompensated kidneys within the spectrum of hydronephrosis. This classification may have prognostic implications when surgery is being considered. In addition, underlying uropathy can be identified on the anatomical scans and renal scarring can be seen on both the anatomical and dynamic scans. MRU can identify and categorize dysmorphic kidneys in vivo and may provide insight into congenital abnormalities seen in conjunction with vesicoureteric reflux. MRU is still in its infancy and as the technique develops and becomes widely available, it seems likely that it will supplant renal scintigraphy in the evaluation of renal tract disorders in children. J. Magn. Reson. Imaging 2011;33:510–526. © 2011 Wiley‐Liss, Inc.
Noninvasive assessment of bleomycin‐induced lung injury and the effects of short‐term glucocorticosteroid treatment in rats using MRI
Authors: Babin Anna L. , Cannet Catherine , Gérard Christelle , Wyss Daniel , Page Clive P. , Beckmann Nicolau
Published: February 2011

Purpose:

To demonstrate the feasibility of proton MRI to noninvasively quantify bleomycin‐induced injury and the effects of glucocorticosteroids in a rat model of lung fibrosis.

Materials and Methods:

Sprague‐Dawley rats received bleomycin intra‐tracheally and underwent MRI up to day 70 following injury onset. A subgroup of animals was treated with budesonide.

Results:

The response in the first 2 weeks post‐bleomycin, characterized by diffuse MRI signals, was related primarily to inflammation as confirmed by histology. Later, increased signals reflected principally tissue remodeling involved in fibrosis development, as suggested by histological analysis revealing collagen deposition in the same areas where MRI signals had been detected. Budesonide administration at days 6 and 13 after bleomycin resulted in decreased MRI signals 24 h after each corticosteroid application. However, no complete signal resolution was observed. Histology showed that budesonide affected inflammation but not fibrosis.

Conclusion:

The ability of MRI to noninvasively quantify lung injury in bleomycin‐treated rats will facilitate in vivo pharmacological studies in this model of pulmonary fibrosis. Repetitive measurements open new avenues in testing compounds as the responses at several time points during the course of treatment can be easily compared. Specifically, studies at the chronic phase, when fibrosis is already established, become amenable. J. Magn. Reson. Imaging 2011;33:603–614. © 2011 Wiley‐Liss, Inc.
Amide proton transfer MR imaging of prostate cancer: A preliminary study
Authors: Jia Guang , Abaza Ronney , Williams JoAnna D. , Zynger Debra L. , Zhou Jinyuan , Shah Zarine K. , Patel Mitva , Sammet Steffen , Wei Lai , Bahnson Robert R. , Knopp Michael V.
Published: February 2011

Purpose:

To evaluate the capability of amide proton transfer (APT) MR imaging for detection of prostate cancer that typically shows a higher tumor cell proliferation rate and cellular density leading to an MRI‐detectable overall elevated mobile protein level in higher grade tumors.

Materials and Methods:

Twelve patients with biopsy‐proven prostate cancer were imaged on a 3 Tesla MR imaging system before prostatectomy. APT‐MR images were acquired by means of a single‐slice single‐shot turbo spin echo sequence with a saturation prepulse preparation using 33 different frequency offsets (−8 to 8 ppm, interval 0.5 ppm). For quantification we used the APT ratio (APTR) based on the asymmetry of the magnetization transfer ratio at 3.5 ppm in respect to the water signal. Tumor and peripheral zone benign regions of interest (ROIs) were delineated based on whole mount pathology slides after prostatectomy.

Results:

APTR in prostate cancer ROIs was 5.8% ± 3.2%, significantly higher than that in the peripheral zone benign regions (0.3% ± 3.2%, P = 0.002).

Conclusion:

APT‐MR imaging is feasible in prostate cancer detection and has the potential to discriminate between cancer and noncancer tissues. J. Magn. Reson. Imaging 2011;33:647–654. © 2011 Wiley‐Liss, Inc.
Quantitative analysis of vertebral bone marrow perfusion using dynamic contrast‐enhanced MRI: Initial results in osteoporotic patients with acute vertebral fracture
Authors: Biffar Andreas , Schmidt Gerwin P. , Sourbron Steven , D'Anastasi Melvin , Dietrich Olaf , Notohamiprodjo Mike , Reiser Maximilian F. , Baur‐Melnyk Andrea
Published: February 2011

Purpose:

To evaluate the potential of quantitative dynamic contrast‐enhanced MRI (DCE‐MRI) in vertebral bone marrow (vBM) of patients with acute osteoporotic vertebral compression fractures.

Materials and Methods:

Twenty‐six patients with acute osteoporotic fractures (16 female, 10 male, median age 72, range 48–89) and 10 subjects without known history of osteoporosis (6 female, 4 male, median 65, range 31–77) were examined 2D‐DCE‐MRI. Region of interest (ROI) data in fractured (n = 26) and normal‐appearing vertebrae (n = 271) were analyzed with a two‐compartment tracer‐kinetic‐model, providing estimates of at least three independent parameters: plasma flow (PF), plasma volume (PV), and extraction flow (EF). Parameters were correlated with dual x‐ray absorptiometry (DXA) (n = 15) and quantitative computed tomography (QCT) densitometry (n = 10).

Results:

Mean PF was significantly higher in fractures than in normal‐appearing vertebrae (69.37 vs. 11.72 mL/100 mL/min). Similarly, mean PV and EF differed significantly. Mean PF was significantly decreased in normal‐appearing vBM osteoporotic patients compared to the control group. Mean PF and PV were significantly decreased in lumbar compared to thoracic vertebrae. PV showed a significant correlation with QCT.

Conclusion:

Perfusion parameters were decreased significantly in normal‐appearing vBM of patients. Furthermore, significant perfusion alterations were observed in acute osteoporotic vertebral fractures compared to normal‐appearing vertebrae. J. Magn. Reson. Imaging 2011;33:676–683. © 2011 Wiley‐Liss, Inc.
Clinical evaluation of MR temperature monitoring of laser‐induced thermotherapy in human liver using the proton‐resonance‐frequency method and predictive models of cell death
Authors: Kickhefel Antje , Rosenberg Christian , Weiss Clifford R. , Rempp Hansjörg , Roland Joerg , Schick Fritz , Hosten Norbert
Published: February 2011

Purpose:

To assess the feasibility, precision, and accuracy of real‐time temperature mapping (TMap) during laser‐induced thermotherapy (LITT) for clinical practice in patients liver with a gradient echo (GRE) sequence using the proton resonance frequency (PRF) method.

Materials and Methods:

LITT was performed on 34 lesions in 18 patients with simultaneous real‐time visualization of relative temperature changes. Correlative contrast‐enhanced T1‐weighted magnetic resonance (MR) images of the liver were acquired after treatment using the same slice positions and angulations as TMap images acquired during LITT. For each slice, TMap and follow‐up images were registered for comparison. Afterwards, segmentation based on temperature (T) >52°C on TMap and based on necrosis seen on follow‐up images was performed. These segmented structures were overlaid and divided into zones where the TMap was found to either over‐ or underestimate necrosis on the postcontrast images. Regions with T>52°C after 20 minutes were defined as necrotic tissue based on data received from two different thermal dose models.

Results:

The average intersecting region of TMap and necrotic zone was 87% ± 5%, the overestimated 13% ± 4%, and the underestimated 13% ± 5%.

Conclusion:

This study demonstrates that MR temperature mapping appears reasonably capable of predicting tissue necrosis on the basis of indicating regions having greater temperatures than 52°C and could be used to monitor and adjust the thermal therapy appropriately during treatment. J. Magn. Reson. Imaging 2011;33:704–712. © 2011 Wiley‐Liss, Inc.
Blood oxygen level‐dependent (BOLD) MRI of diabetic nephropathy: Preliminary experience
Authors: Wang Zhen J. , Kumar Rahi , Banerjee Suchandrima , Hsu Chi‐yuan
Published: February 2011

Purpose:

To evaluate the blood oxygen level‐dependent (BOLD) magnetic resonance imaging (MRI) findings in kidneys of patients with diabetic nephropathy.

Materials and Methods:

BOLD MRI of the kidneys (1.5 T, multigradient‐recalled‐echo sequence with 12 echoes) was performed in 20 patients with diabetic nephropathy (moderate to severe chronic kidney disease: n = 14; mild chronic kidney disease: n = 6), and seven healthy volunteers. The medullary and cortical R2* values were compared between patients with diabetic nephropathy and healthy volunteers using Student's t‐tests.

Results:

The mean medullary R2* values were lower in patients with diabetic nephropathy compared to healthy volunteers (13.8 ± 2.4 sec−1 vs. 19.3 ± 1.2 sec−1, P = 0.0002). The cortical R2* values were not significantly different between the two groups (11.1 ± 0.9 sec−1 vs. 11.5 ± 0.7 sec−1, P = 0.7). A multiple logistic regression model using patient age, gender, and degree of chronic kidney disease (none, mild, or moderate to severe) as variables showed that the degree of kidney disease was independently associated with a decrease in medullary R2* values (P = 0.005).

Conclusion:

The medullary R2* values were lower in patients with diabetic nephropathy compared to healthy volunteers. J. Magn. Reson. Imaging 2011;33:655–660. © 2011 Wiley‐Liss, Inc.
Iron deposition surrounding the hepatic veins of cirrhotic patients on MRI
Authors: Horowitz Jeanne M. , Nikolaidis Paul , Chen Zong‐Ming E. , Siegelman Evan , Garg Akash , Feng Chun , Miller Frank H.
Published: February 2011

Purpose:

To provide the first description of a pattern of iron deposition surrounding the hepatic veins in patients with alcoholic cirrhosis and postulate the reason for these findings.

Materials and Methods:

Two institutions' teaching files were searched for abdominal MRI studies between January 2003 and April 2009 which showed iron deposition within the liver surrounding the hepatic veins. MRI exams were reviewed by two radiologists for iron deposition and signs of portal hypertension. Liver explant pathology reports were also reviewed.

Results:

Four patients with alcoholic cirrhosis demonstrated perihepatic vein low signal intensity on T1 gradient echo images correlating with iron overload confirmed at histopathologic evaluation of explanted livers.

Conclusion:

This is the first described uncommon distribution of iron deposition surrounding the hepatic veins. This pattern is well seen on in‐phase T1 gradient echo sequences because of the T2* effects in this sequence. J. Magn. Reson. Imaging 2011;33:598–602. © 2011 Wiley‐Liss, Inc.