bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of alendronate and vitamin D3 on fractional calcium absorption in a double-blind, randomized, placebo-controlled trial in postmenopausal osteoporotic women
Authors: Shapses Sue A , Kendler David L , Robson Richard , Hansen Karen E , Sherrell Robert M , Field M Paul , Woolf Eric , Berd Yulia , Mantz Ann Marie , Santora Arthur C
Published: March 2011

Menopause and increasing age are associated with a decrease in calcium absorption that can contribute to the pathogenesis of osteoporosis. We hypothesized that alendronate plus vitamin D3 (ALN + D) would increase fractional calcium absorption (FCA). In this randomized, double-blind, placebo-controlled multicenter clinical trial, 56 postmenopausal women with 25-hydroxyvitamin D [25(OH)D] concentrations of 25 ng/mL or less and low bone mineral density (BMD) received 5 weekly doses of placebo or alendronate 70 mg plus vitamin D3 2800 IU (ALN + D). Calcium intake was stabilized to approximately 1200 mg/d prior to randomization. FCA was determined using a dual-tracer stable-calcium isotope method. FCA and 25(OH)D were similar between treatment groups at baseline (0.31 ± 0.12 ng/mL and 19.8 ± 4.7 ng/mL, respectively). After 1 month of treatment, subjects randomized to ALN + D experienced a significant least squares (LS) mean [95% confidence interval (CI)] increase in FCA [0.070 (0.042, 0.098)], whereas FCA did not change significantly in the placebo group [−0.016 (−0.044, 0.012)]. After ALN + D treatment, patients had higher 25(OH)D levels (LS mean difference 7.3 ng/mL, p < .001). The rise in serum 1,25-dihydroxyvitamin D3 (p < .02) and parathyroid hormone (p < .001) were greater in the ALN + D group than in placebo-treated patients. ALN + D was associated with an increase in FCA of 0.07. To our knowledge, there is no other trial showing such a marked rise in calcium absorption owing to treatment with a bisphosphonate or owing to a small rise in 25(OH)D. This unique response of ALN + D is important for the treatment of osteoporosis, but the exact mechanism requires further study. © 2011 American Society for Bone and Mineral Research
Insight among psychotic patients with auditory hallucinations
Authors: Lera Guillem , Herrero Neus , González Jose , Aguilar Eduardo , Sanjuán Julio , Leal Carmen
Published: March 2011

Poor insight in psychosis has been described as a seeming lack of awareness of the deficits, consequences of the disorder, and of the need for treatment. The aim of this study is to investigate whether patients with auditory hallucinations have less insight than those without hallucinations, and to determine which hallucination characteristics are related to patient insight. Using the PANSS and PSYRATS, the authors have evaluated the lack of insight data corresponding to 168 psychotic patients divided into three groups: patients with a history of nonpersistent hallucinations, patients with persistent hallucinations, and patients without hallucinations. Patients with persistent hallucinations showed significantly less insight than patients without persistent hallucinations and patients without hallucinations, the farther away the hallucination is located, the greater the lack of patient insight. Patients who hear the hallucination inside their head rather than outside show better insight, possibly because such patients can understand the voice as being created by their own mind. © 2011 Wiley Periodicals, Inc. J Clin Psychol 67:701–708, 2011.
Wnt/β‐catenin signaling pathway and thioredoxin‐interacting protein (TXNIP) mediate the “glucose sensor” mechanism in metastatic breast cancer‐derived cells MDA‐MB‐231
Authors: Vaira Sergio , Friday Ellen , Scott Keith , Conrad Steven , Turturro Francesco
Published: March 2011

In this study we investigated the effect of glucose on GSK3β and β‐catenin expression and the involvement of the N‐linked glycosylation and hexosamine pathways in the Wnt canonical pathway in response to in vitro conditions resembling normoglycemia (5 mmol) and hyperglycemia (20 mmol) in the metastatic breast cancer‐derived cell line MDA‐MB‐231. We also investigated the relationship between this circuitry and the thioredoxin‐interacting protein (TXNIP) regulation that seems to be related. MDA‐MB‐231 cells were grown either in 5 or 20 mM glucose chronically prior to plating. For glucose shift (5/20), cells were plated in 5 mM glucose and shifted to 20 mM at time 0. Both protein and mRNA levels for GSK3β but only the protein expression for β‐catenin, were increased in response to high glucose. Furthermore, we assessed the response of GSK3β, β‐catenin, and TXNIP to inhibition of the N‐linked glycosylation, hexosamine, and Wnt pathways. Wnt signaling pathway activation was validated by specific reporter assay. We show that high levels of glucose regulate mRNA and protein expression of GSK3β, and consequently higher levels of activated β‐catenin protein, which locates to the nucleus and is associated with increased levels of cyclin D1 expression. This event coincides with increased level of N‐terminal Ser 9 phosphorylation of GSK3β protein. The inhibition of both the hexosamine pathway and N‐linked glycosylation along with Wnt signaling pathway by sFRP1 and DKK1 is associated with significant decrease of the protein levels of GSK3β, β‐catenin, and TXNIP RNA. Our work illuminates a novel and never described before function of this signaling pathway that relates glucose metabolism with redox regulation mechanism. J. Cell. Physiol. 227: 578–586, 2012. © 2011 Wiley Periodicals, Inc.
Modulation of the tumor cell death pathway by androgen receptor in response to cytotoxic stimuli
Authors: Frezza Michael , Yang Huanjie , Dou Q. Ping
Published: March 2011

Despite an initial response from androgen deprivation therapy, most prostate cancer patients relapse to a hormone‐refractory state where tumors still remain dependent on androgen receptor (AR) function. We have previously shown that AR breakdown correlates with the induction of cancer cell apoptosis by proteasome inhibition. However, the involvement of AR in modulating the cell death pathway has remained elusive. To investigate this, we used an experimental model consisting of parental PC‐3 prostate cancer cells that lack AR expression and PC‐3 cells stably overexpressing wild type AR gene. Here, we report that both chemotherapeutic drugs (cisplatin) and proteasome inhibitors induced caspase‐3‐associated cell death in parental PC‐3 cells whereas non‐caspase‐3 associated cell death in PC3‐AR cells. The involvement of AR in modulating tumor cell death was further confirmed in PC‐3 cells transiently expressing AR. Consistently, treatment with the clinically used proteasome inhibitor Bortezomib (Velcade/PS‐341) of (AR+) LNCaP prostate cancer cells caused AR cleavage and cell death with low levels of caspase activation. However, co‐treatment with Bortezomib and the AR antagonist Bicalutamide (Casodex) caused significant decrease in AR expression associated with an increase in caspase‐3 activity in both LNCaP and PC3‐AR cells. Thus our results provide compelling evidence for involvement of AR in deciding types of tumor cell death upon cytotoxic stimuli, and specifically, blockade of AR activities could change necrosis to apoptosis in tumor cells. Our findings may help guide clinicians based on AR status in the design of favorable treatment strategies for prostate cancer patients. J. Cell. Physiol. 226: 2731–2739, 2011. © 2011 Wiley‐Liss, Inc.
Regulation of reactive oxygen species in stem cells and cancer stem cells
Authors: Kobayashi Chiharu I. , Suda Toshio
Published: March 2011

Stem cells are defined by their ability to self‐renew and their multi‐potent differentiation capacity. As such, stem cells maintain tissue homeostasis throughout the life of a multicellular organism. Aerobic metabolism, while enabling efficient energy production, also generates reactive oxygen species (ROS), which damage cellular components. Until recently, the focus in stem cell biology has been on the adverse effects of ROS, particularly the damaging effects of ROS accumulation on tissue aging and the development of cancer, and various anti‐oxidative and anti‐stress mechanisms of stem cells have been characterized. However, it has become increasingly clear that, in some cases, redox status plays an important role in stem cell maintenance, i.e., regulation of the cell cycle. An active area of current research is redox regulation in various cancer stem cells, the malignant counterparts of normal stem cells that are viewed as good targets of cancer therapy. In contrast to cancer cells, in which ROS levels are increased, some cancer stem cells maintain low ROS levels, exhibiting redox patterns that are similar to the corresponding normal stem cell. To fully elucidate the mechanisms involved in stem cell maintenance and to effectively target cancer stem cells, it is essential to understand ROS regulatory mechanisms in these different cell types. Here, the mechanisms of redox regulation in normal stem cells, cancer cells, and cancer stem cells are reviewed. J. Cell. Physiol. 227: 421–430, 2012. © 2011 Wiley Periodicals, Inc.
Non‐dispersive absorption for CO2 capture: from the laboratory to industry
Authors: Luis Patricia , Van der Bruggen Bart , Van Gerven Tom
Published: March 2011

Research on capture and recovery of CO2 has become a critical topic in the development of technological answers to the greenhouse effect. Conventional industrial processes do not fit into the philosophy of process intensification in which a radically new approach should lead to environmentally friendly methods with minimal use of natural resources and production of secondary waste. Conventional processes involve the use of large amounts of toxic organic solvents, such as diethylamine, and large equipment (e.g. absorption columns). Although CO2 recovery began in industrial operation more than fifty years ago and, in spite of the clear potential for intensified processes demonstrated in the scientific literature, there is no real evidence that new processes for CO2 recovery will achieve industrial implementation in the short term. In this perspective, the main limitations of membrane systems based on non‐dispersive absorption using porous membranes are outlined, in order to identify the main challenges that still have to be solved to achieve an industrially attractive process for CO2 recovery. Copyright © 2011 Society of Chemical Industry
A novel Doppler spectral index for differentiating benign from malignant lung tumors
Authors: Wu Tsung‐Ju , Shiao Judith Shu‐Chu , Lu Jau‐Yeong
Published: March 2011

Purpose:

It has been reported that the resistance index (RI) and pulsatility index (PI) are of limited value in differentiating lung cancers from benign lesions. We hypothesized that a vascular work index (VWI), derived from Doppler spectral waveforms, would yield better results.

Methods:

Forty‐one patients were enrolled, 20 of them having malignancies and 21 having benign lesions. The VWI was defined as the square of peak systolic velocity times the time‐velocity integral. Maximal VWI, minimal RI, and minimal PI of each tumor were used for analysis.

Results:

Significantly higher VWI values were found in malignant tumors compared with benign lesions (p < 0.0001). VWI was shown by analysis of the receiver operating characteristic curve to be a best predictor of lung malignancies than PI and RI (p < 0.05), with a 0.89 (95% confidence interval, 0.80–0.98) area under the receiver operating characteristic curve.

Conclusions:

VWI may be a useful index to help differentiate malignant from benign lung tumors. © 2011 Wiley Periodicals, Inc. J Clin Ultrasound 2011;
Infarction of lesser omental fat mimicking an exophytic pancreatic tumor by sonography
Authors: Kim Hyun Cheol , Yang Dal Mo , Jin Wook , Joh Jin Hyun
Published: March 2011

We report a case of infarction of lesser omental fat in a 30‐year‐old woman who presented with epigastric pain. Sonography revealed a painful echogenic mass in the epigastrium that could not be separated from the adjacent hyperechoic pancreas and mimicked an exophytic pancreatic tumor. On CT, the mass was identified as an inflammatory lipomatous mass in the lesser sac, leading to the diagnosis of infarction of lesser omental fat. The patient was successfully treated conservatively. © 2011 Wiley Periodicals,Inc. J Clin Ultrasound, 2011
Sonographic evaluation of the development of the fetal rectum and anal canal
Authors: Su Yi‐Ming , Ye Zhen , Chen Xiao‐Yu , Liu Xin‐Xiu , Chen Shu‐Qiang
Published: March 2011

Purpose.

To describe the sonographic (US) appearance of fetal anal canal and rectum and establish nomograms of their normal measurements.

Methods.

This was a prospective, cross‐sectional study of 524 healthy women (mean age, 27 years; range, 21–37 years) with normal singleton pregnancy between 18 and 40 weeks of gestational age (GA). High‐resolution transabdominal US was used to visualize and measure the normal fetal anal canal and rectum.

Results.

Satisfactory images and measurements of the fetal anal canal and rectum were obtained in 496 normal fetuses. The diameters of the normal anal canal and rectum were plotted as a function of GA in a sigmoid curve. The curve estimations were expressed by the following cubic regression equations with R2 of 0.87 and 0.88, respectively (p < 0.001): anal canal diameter (mm) = 18.272 − 2.151 × GA + 0.0095 × GA2 − 0.0011 × GA3, and rectal diameter (mm) = 18.545 − 2.543 × GA + 0.1237 × GA2 − 0.0016 × GA3.

Conclusions.

The fetal anal canal and rectum are visible sonographically between 18 and 40 weeks of GA. The knowledge of their normal US appearance and size from the second trimester of pregnancy onwards may help identify developmental anomalies. © 2011 Wiley Periodicals, Inc. J Clin Ultrasound, 2011
Nutcracker syndrome in a patient with a history of inferior vena cava ligation
Authors: Peker Ahmet , Yagmurlu Aydın , Ekim Mesiha , Gokcora Haluk , Fitoz Suat
Published: March 2011

We report the case of a child with clinical and radiological signs of nutcracker syndrome who had a history of inferior vena cava ligation during a previous surgery. He was referred for evaluation of abdominal pain and hematuria. Entrapment of the left renal vein between the superior mesenteric artery and the aorta with aneurysmal dilatation was detected on Doppler ultrasonography. Magnetic resonance angiography revealed paravertebral and epidural collateral vessels.© 2011 Wiley Periodicals, Inc. J Clin Ultrasound, 2011
Routine 3D magnetic resonance imaging of joints
Authors: Kijowski Richard , Gold Garry E.
Published: March 2011

Due to its high spatial resolution and excellent tissue contrast, magnetic resonance imaging (MRI) has become the most commonly used imaging method to evaluate joints. Most musculoskeletal MRI is performed using 2D fast spin‐echo sequences. However, 3D sequences have also been used for joint imaging and have the advantage of acquiring thin continuous slices through joints, which reduces the effects of partial volume averaging. With recent advances in MR technology, 3D sequences with isotropic resolution have been developed. These sequences allow high‐quality multiplanar reformat images to be obtained following a single acquisition, thereby eliminating the need to repeat sequences with identical tissue contrast in different planes. Preliminary results on the diagnostic performance of 3D isotropic resolution sequences are encouraging. However, additional studies are needed to determine whether these sequences can replace currently used 2D fast spin‐echo sequences for providing comprehensive joint assessment in clinical practice. J. Magn. Reson. Imaging 2011;33:758–771. © 2011 Wiley‐Liss, Inc.
Magnetization‐prepared IDEAL bSSFP: A flow‐independent technique for noncontrast‐enhanced peripheral angiography
Authors: Çukur Tolga , Shimakawa Ann , Yu Huanzhou , Hargreaves Brian A. , Hu Bob S. , Nishimura Dwight G. , Brittain Jean H.
Published: March 2011

Purpose:

To propose a new noncontrast‐enhanced flow‐independent angiography sequence based on balanced steady‐state free precession (bSSFP) that produces reliable vessel contrast despite the reduced blood flow in the extremities.

Materials and Methods:

The proposed technique addresses a variety of factors that can compromise the exam success including insufficient background suppression, field inhomogeneity, and large volumetric coverage requirements. A bSSFP sequence yields reduced signal from venous blood when long repetition times are used. Complex‐sum bSSFP acquisitions decrease the sensitivity to field inhomogeneity but retain phase information, so that data can be processed with the Iterative Decomposition of Water and Fat with Echo Asymmetry and Least‐Squares Estimation (IDEAL) method for robust fat suppression. Meanwhile, frequent magnetization preparation coupled with parallel imaging reduces the muscle and long‐T1 fluid signals without compromising scan efficiency.

Results:

In vivo flow‐independent peripheral angiograms with reliable background suppression and high spatial resolution are produced. Comparisons with phase‐sensitive bSSFP angiograms (that yield out‐of‐phase fat and water signals, and exploit this phase difference to suppress fat) demonstrate enhanced vessel depiction with the proposed technique due to reduced partial‐volume effects and improved venous suppression.

Conclusion:

Magnetization‐prepared complex‐sum bSSFP with IDEAL fat/water separation can create reliable flow‐independent angiographic contrast in the lower extremities. J. Magn. Reson. Imaging 2011;33:931–939. © 2011 Wiley‐Liss, Inc.
Effect of MRI strength and propofol sedation on pediatric core temperature change
Authors: Isaacson Diane L. , Yanosky Daniel J. , Jones Richard A. , Dennehy Nancy , Spandorfer Philip , Baxter Amy L.
Published: March 2011

Purpose:

To determine core body temperature variations in children undergoing MRI exams on 1.5 Tesla (T) and 3T magnetic field strengths and with and without propofol sedation.

Materials and Methods:

Temporal artery temperatures were prospectively collected on 400 consecutive patients undergoing 1.5 Tesla (T) or 3.0T MRI scans. A cumulative logistic regression model was created using age, weight, MRI protocol, sedation status, pre‐MRI temperature and MRI strength to assess risk of temperature change.

Results:

For patients with complete pre‐ and post‐MRI temperature data, mean temperatures did not significantly change (−0.0155°C, 95%CI, −0.035, 0.064; n = 385). Temperature changes differed significantly between propofol‐sedated and nonsedated patients (−0.26°C ± .44 versus 0.24°C ± 0.42;P< 0.0001), as did temperature changes for patients on the 3T (0.076°C ± 0.52) versus 1.5T (−0.06°C ± 0.48;P= 0.011). Sedation status, age, MRI strength, and MRI protocol accounted for 44.17% of temperature variance. The temperatures of 15 patients' (3.9%) decreased >1°C; 12 were on the 1.5T. All 7 patients (1.8%) who increased >1°C were non‐sedates.

Conclusion:

Clinically significant core body temperature change is uncommon in children undergoing MRI with different magnetic field strengths, and with and without propofol sedation. J. Magn. Reson. Imaging 2011;33:950–956. © 2011 Wiley‐Liss, Inc.
Automated ischemic lesion detection in a neonatal model of hypoxic ischemic injury
Authors: Ghosh Nirmalya , Recker Rebecca , Shah Amul , Bhanu Bir , Ashwal Stephen , Obenaus Andre
Published: March 2011

Purpose:

To develop and compare an automated detection system for ischemic lesions in a neonatal model of bilateral carotid artery occlusion with hypoxia (BCAO‐H) from T2 weighted MRI (T2WI) to the currently used “gold standard” of manual segmentation.

Materials and Methods:

Forty‐three P10 BCAO‐H rat pups and 8 controls underwent T2WI at 1 day and 28 days. A computational imaging method, Hierarchical Region Splitting (HRS), was developed to automatically and rapidly detect and quantify 3D lesion and normal appearing brain matter (NABM) volumes.

Results:

HRS quantified lesion and NABM volumes within 15 s in comparison to 3 h for its manual counterpart, with a high correlation for injury (r2 = 0. 95; P = 8.6 × 10−7) and NABM (r2 = 0. 92; P = 1.4 × 10−22). Average lesion volumes for mild, moderate, and severe injuries were 3.85%, 28.85%, and 52.98% for HRS and 0.51%, 24.22%, and 48.74% for manual detection. Lesion volumes and locations were similar for both methods (sensitivity: 0.82, specificity: 0.86, and similarity: 1.47).

Conclusion:

HRS is an accurate, objective, and rapid method to quantify injury evolution in neonatal hypoxic ischemic injury models. J. Magn. Reson. Imaging 2011;33:772–781. © 2011 Wiley‐Liss, Inc.
Quantification of vertebral bone marrow fat content using 3 tesla MR spectroscopy: Reproducibility, vertebral variation, and applications in osteoporosis
Authors: Li Xiaojuan , Kuo Daniel , Schafer Anne L. , Porzig Anne , Link Thomas M. , Black Dennis , Schwartz Ann V.
Published: March 2011

Purpose:

To determine the reproducibility of proton MR spectroscopy (1H‐MRS) for assessing vertebral bone marrow adiposity at 3 Tesla (T); to evaluate variation of marrow adiposity at different vertebral levels; and to demonstrate the feasibility of using 1H‐MRS at 3T for evaluating marrow adiposity in subjects with low bone density.

Materials and Methods:

Single voxel MRS was acquired at vertebral body L1 to L4 at 3T in 51 postmenopausal females including healthy controls (n = 13) and patients with osteoporosis/osteopenia (n = 38). Marrow fat contents were compared between vertebral levels and between groups using analysis of variance (ANOVA). Six subjects were scanned twice to evaluate technique reproducibility.

Results:

The average coefficient of variation of vertebral marrow fat content quantification was 1.7%. Marrow fat content significantly increased from L1 to L4. The average fat content was significantly elevated in patients with osteoporosis/osteopenia compared with controls, adjusted for age and body mass index (P < 0.05).

Conclusion:

In vivo MRS at high field strength provides reliable measurement of marrow adiposity with excellent reproducibility and can be a valuable tool for providing complementary information on bone quality and potentially also fracture risk. J. Magn. Reson. Imaging 2011;33:974–979. © 2011 Wiley‐Liss, Inc.
Impact of nonrigid motion correction technique on pixel‐wise pharmacokinetic analysis of free‐breathing pulmonary dynamic contrast‐enhanced MR imaging
Authors: Tokuda Junichi , Mamata Hatsuho , Gill Ritu R. , Hata Nobuhiko , Kikinis Ron , Padera Robert F. , Lenkinski Robert E. , Sugarbaker David J. , Hatabu Hiroto
Published: March 2011

Purpose:

To investigates the impact of nonrigid motion correction on pixel‐wise pharmacokinetic analysis of free‐breathing DCE‐MRI in patients with solitary pulmonary nodules (SPNs). Misalignment of focal lesions due to respiratory motion in free‐breathing dynamic contrast‐enhanced MRI (DCE‐MRI) precludes obtaining reliable time–intensity curves, which are crucial for pharmacokinetic analysis for tissue characterization.

Materials and Methods:

Single‐slice 2D DCE‐MRI was obtained in 15 patients. Misalignments of SPNs were corrected using nonrigid B‐spline image registration. Pixel‐wise pharmacokinetic parameters Ktrans, ve, and kep were estimated from both original and motion‐corrected DCE‐MRI by fitting the two‐compartment pharmacokinetic model to the time–intensity curve obtained in each pixel. The “goodness‐of‐fit” was tested with χ2‐test in pixel‐by‐pixel basis to evaluate the reliability of the parameters. The percentages of reliable pixels within the SPNs were compared between the original and motion‐corrected DCE‐MRI. In addition, the parameters obtained from benign and malignant SPNs were compared.

Results:

The percentage of reliable pixels in the motion‐corrected DCE‐MRI was significantly larger than the original DCE‐MRI (P = 4 × 10−7). Both Ktrans and kep derived from the motion‐corrected DCE‐MRI showed significant differences between benign and malignant SPNs (P = 0.024, 0.015).

Conclusion:

The study demonstrated the impact of nonrigid motion correction technique on pixel‐wise pharmacokinetic analysis of free‐breathing DCE‐MRI in SPNs. J. Magn. Reson. Imaging 2011;33:968–973. © 2011 Wiley‐Liss, Inc.
Diagnostic usefulness of water‐to‐fat ratio and choline concentration in malignant and benign breast lesions and normal breast parenchyma: An in vivo 1H MRS study
Authors: Thakur Sunitha B. , Brennan Sandra B. , Ishill Nicole M. , Morris Elizabeth A. , Liberman Laura , Dershaw D. David , Bartella Lia , Koutcher Jason A. , Huang Wei
Published: March 2011

Purpose:

To compare total choline concentrations ([Cho]) and water‐to‐fat (W/F) ratios of subtypes of malignant lesions, benign lesions, and normal breast parenchyma and determine their usefulness in breast cancer diagnosis. Reference standard was histology.

Materials and Methods:

In this HIPPA compliant study, proton MRS was performed on 93 patients with suspicious lesions (>1 cm) who underwent MRI‐guided interventional procedures, and on 27 prospectively accrued women enrolled for screening MRI. (W/F) and [Cho] values were calculated using MRS data.

Results:

Among 88 MRS‐evaluable histologically‐confirmed lesions, 40 invasive ductal carcinoma (IDC); 10 invasive lobular carcinoma (ILC); 4 ductal carcinoma in situ (DCIS); 3 invasive mammary carcinoma (IMC); 31 benign. No significant difference observed in (W/F) between benign lesions and normal breast tissue. The area under curve (AUC) of receiver operating characteristic (ROC) curves for discriminating the malignant group from the benign group were 0.97, 0.72, and 0.99 using [Cho], (W/F) and their combination as biomarkers, respectively. (W/F) performs significantly (P < 0.0001;AUC = 0.96) better than [Cho] (AUC = 0.52) in differentiating IDC and ILC lesions.

Conclusion:

Although [Cho] and (W/F) are good biomarkers for differentiating malignancy, [Cho] is a better marker. Combining both can further improve diagnostic accuracy. IDC and ILC lesions have similar [Cho] levels but are discriminated using (W/F) values. J. Magn. Reson. Imaging 2011;33:855–863. © 2011 Wiley‐Liss, Inc.
Multimode intravascular RF coil for MRI‐guided interventions
Authors: Kurpad Krishna N. , Unal Orhan
Published: March 2011

Purpose:

To demonstrate the feasibility of using a single intravascular radiofrequency (RF) probe connected to the external magnetic resonance imaging (MRI) system via a single coaxial cable to perform active tip tracking and catheter visualization and high signal‐to‐noise ratio (SNR) intravascular imaging.

Materials and Methods:

A multimode intravascular RF coil was constructed on a 6F balloon catheter and interfaced to a 1.5T MRI scanner via a decoupling circuit. Bench measurements of coil impedances were followed by imaging experiments in saline and phantoms.

Results:

The multimode coil behaves as an inductively coupled transmit coil. The forward‐looking capability of 6 mm was measured. A greater than 3‐fold increase in SNR compared to conventional imaging using optimized external coil was demonstrated. Simultaneous active tip tracking and catheter visualization was demonstrated.

Conclusion:

It is feasible to perform 1) active tip tracking, 2) catheter visualization, and 3) high SNR imaging using a single multimode intravascular RF coil that is connected to the external system via a single coaxial cable. J. Magn. Reson. Imaging 2011;33:995–1002. © 2011 Wiley‐Liss, Inc.
Improved spatial coverage for brain 3D PRESS MRSI by automatic placement of outer‐volume suppression saturation bands
Authors: Ozhinsky Eugene , Vigneron Daniel B. , Nelson Sarah J.
Published: March 2011

Purpose:

To develop a technique for optimizing coverage of brain 3D 1H magnetic resonance spectroscopic imaging (MRSI) by automatic placement of outer‐volume suppression (OVS) saturation bands (sat bands) and to compare the performance for point‐resolved spectroscopic sequence (PRESS) MRSI protocols with manual and automatic placement of sat bands.

Materials and Methods:

The automated OVS procedure includes the acquisition of anatomic images from the head, obtaining brain and lipid tissue maps, calculating optimal sat band placement, and then using those optimized parameters during the MRSI acquisition. The data were analyzed to quantify brain coverage volume and data quality.

Results:

3D PRESS MRSI data were acquired from three healthy volunteers and 29 patients using protocols that included either manual or automatic sat band placement. On average, the automatic sat band placement allowed the acquisition of PRESS MRSI data from 2.7 times larger brain volumes than the conventional method while maintaining data quality.

Conclusion:

The technique developed helps solve two of the most significant problems with brain PRESS MRSI acquisitions: limited brain coverage and difficulty in prescription. This new method will facilitate routine clinical brain 3D MRSI exams and will be important for performing serial evaluation of response to therapy in patients with brain tumors and other neurological diseases. J. Magn. Reson. Imaging 2011;33:792–802. © 2011 Wiley‐Liss, Inc.
Fast monitoring of T1, T2, and relative proton density (M0) changes in skeletal muscles using an IR‐TrueFISP sequence
Authors: de Sousa Paulo Loureiro , Vignaud Alexandre , Fleury Servanne , Carlier Pierre G.
Published: March 2011

Purpose:

To investigate the feasibility of fast and simultaneous assessment of T1, T2, and M0 (relative proton density) changes in skeletal muscle studies using an inversion recovery true fast imaging with steady‐state precession (TrueFISP) sequence.

Materials and Methods:

NMR signal dynamics in calf muscles were analyzed under four different conditions: intravenous injection of a low‐molecular weight Gd contrast agent (CA), postarterial occlusion reactive hyperemia, local cooling, and an exercise bout. Experiments were conducted on a clinical 3T whole‐body scanner.

Results:

At rest, average muscle T1 and T2 values obtained from the IR‐TrueFISP experiments were 1.34 ± 0.13 seconds and 45 ± 5 msec, respectively (median ± standard deviation). 1) Noticeable T1 decreases (ΔT1 max ≈−30%) were measured in the calf muscles after CA injection, while no significant changes were observed for T2 and M0. 2) T2 increased rapidly during reactive hyperemia and reached a peak value (+6%) at about 1 minute postischemia. During ischemia, a significant decrease was observed only in the soleus muscle. No significant paradigm‐related changes in M0 and T1 were noted in all muscle groups, except in the m. soleus (ΔT1 ≈+1% during reactive hyperemia). 3) Opposite variations in muscle T1 (ΔT1 max ≈−30%) and M0 (ΔM0 max ≈+25%) associated with local cooling were detected. 4) Concomitant changes in T1 (ΔT1 max ≈+15%), T2 (ΔT2 max ≈+35%), and M0 (ΔM0 max ≈+16%) were observed in the activated muscles following the exercise bout.

Conclusion:

IR‐TrueFISP was sufficiently fast and sensitive to detect small and transient T1, T2, and M0 changes in the calf muscles under different experimental conditions. The sequence offers a time‐resolution adequate to track rapid physiological adaptations in skeletal muscle. J. Magn. Reson. Imaging 2011;33:921–930. © 2011 Wiley‐Liss, Inc.
Choline metabolism, proliferation, and angiogenesis in nonenhancing grades 2 and 3 astrocytoma
Authors: McKnight Tracy R. , Smith Kenneth J. , Chu Philip W. , Chiu King S. , Cloyd Colleen P. , Chang Susan M. , Phillips Joanna J. , Berger Mitchel S.
Published: March 2011

Purpose:

To study choline metabolism in biopsies from nonenhancing Grade 2 (AS2) and Grade 3 (AS3) astrocytomas to determine whether (1) phosphocholine (PC) dominates in AS3, and (2) PC is associated with proliferation or angiogenesis. PC and glycerophosphocholine (GPC) are involved in phospholipid metabolism that accompanies mitosis. PC is the predominant peak in Grade 4 astrocytoma (GBM) while GPC dominates in AS2.

Materials and Methods:

We used high resolution magic angle spinning magnetic resonance spectroscopy to compare the concentrations of 10 metabolites in 41 biopsies (16 AS2 and 25 AS3) from 24 tumors. Immunohistochemistry was performed on paired biopsies to determine the cell density, Ki‐67 proliferation index, and vascular endothelial growth factor (VEGF) angiogenic marker expression.

Results:

AS3 had higher PC than AS2; however, the PC:GPC was less than 1 in all cases irrespective of tumor grade. Within tumors, GPC increased with Ki‐67 and PC and tCho increased with cell density. There was no association between any choline compound and VEGF.

Conclusion:

These data suggest that PC:GPC less than 1 is not unique to low grade glioma. Furthermore, the PC concentration that is a marker of aggressive glial tumors is not tightly linked to cell proliferation or angiogenesis in nonenhancing astrocytomas. J. Magn. Reson. Imaging 2011;33:808–816. © 2011 Wiley‐Liss, Inc.
Predictive model to describe water migration in cellular solid foods during storage
Authors: Voogt Juliën A , Hirte Anita , Meinders Marcel BJ
Published: March 2011

BACKGROUND: Water migration in cellular solid foods during storage causes loss of crispness. To improve crispness retention, physical understanding of this process is needed. Mathematical models are suitable tools to gain this physical knowledge.

RESULTS: Water migration in cellular solid foods involves migration through both the air cells and the solid matrix. For systems in which the water migration distance is large compared with the cell wall thickness of the solid matrix, the overall water flux through the system is dominated by the flux through the air. For these systems, water migration can be approximated well by a Fickian diffusion model. The effective diffusion coefficient can be expressed in terms of the material properties of the solid matrix (i.e. the density, sorption isotherm and diffusion coefficient of water in the solid matrix) and the morphological properties of the cellular structure (i.e. water vapour permeability and volume fraction of the solid matrix). The water vapour permeability is estimated from finite element method modelling using a simplified model for the cellular structure.

CONCLUSION: It is shown that experimentally observed dynamical water profiles of bread rolls that differ in crust permeability are predicted well by the Fickian diffusion model. Copyright © 2011 Society of Chemical Industry
Interactive effects of vegetation structure and composition describe bird habitat associations in mixed broadleaf–conifer forest
Authors: Seavy Nathaniel E. , Alexander John D.
Published: March 2011

The effects that changes in forest structure and composition have on wildlife have often been considered independently, such that the potential for interactive effects has received relatively little attention. We investigated the importance of vegetation structure, floristic composition, and their interaction for predicting bird distribution in mixed broadleaf–conifer forest. We collected vegetation and bird data at 979 stations in a watershed in southern Oregon in the spring of 2001. At each station, we described the vegetation using measures of structure (total vegetation volume) and of floristic composition (broadleaf–conifer composition). We then used logistic regression to model the probability of occurrence of bird species as a function of these 2 variables, their quadratic terms, and their interaction. Using stepwise model selection we identified the best model for each species and used area under the curve (AUC) scores to evaluate model performance. Of the 44 bird species we investigated, 20 had models with AUC scores ≥0.70. Of the best models for these 20 species, 1 included vegetation composition alone, 12 included just the main effects of vegetation composition and structure, and 7 included both the main effects and interaction terms. In summer of 2001 a wildfire burned 2,500 ha of the study area, resulting in substantial changes in the vegetation structure and composition. We used 4 yr of postfire bird and vegetation surveys to test the predictive performance of the habitat models for 9 species that occurred at >15% of the burned stations. Models for 3 of these species performed poorly (AUC < 0.7) in all 4 yr. For the other 6 species, predictive performance was low in the first year after fire and improved during subsequent years, suggesting a lagged response to changes in vegetation structure and composition. Quantifying the interactive effects of vegetation structure and composition improves our understanding of how birds respond to forest management and large‐scale disturbances, such as wildfires. © 2011 The Wildlife Society.
Spread of plague among black‐tailed prairie dogs is associated with colony spatial characteristics
Authors: Johnson Tammi L. , Cully Jack F. , Collinge Sharon K. , Ray Chris , Frey Christopher M. , Sandercock Brett K.
Published: March 2011

Sylvatic plague (Yersinia pestis) is an exotic pathogen that is highly virulent in black‐tailed prairie dogs (Cynomys ludovicianus) and causes widespread colony losses and individual mortality rates >95%. We investigated colony spatial characteristics that may influence inter‐colony transmission of plague at 3 prairie dog colony complexes in the Great Plains. The 4 spatial characteristics we considered include: colony size, Euclidean distance to nearest neighboring colony, colony proximity index, and distance to nearest drainage (dispersal) corridor. We used multi‐state mark–recapture models to determine the relationship between these colony characteristics and probability of plague transmission among prairie dog colonies. Annual mapping of colonies and mark–recapture analyses of disease dynamics in natural colonies led to 4 main results: 1) plague outbreaks exhibited high spatial and temporal variation, 2) the site of initiation of epizootic plague may have substantially influenced the subsequent inter‐colony spread of plague, 3) the long‐term effect of plague on individual colonies differed among sites because of how individuals and colonies were distributed, and 4) colony spatial characteristics were related to the probability of infection at all sites although the relative importance and direction of relationships varied among sites. Our findings suggest that conventional prairie dog conservation management strategies, including promoting large, highly connected colonies, may need to be altered in the presence of plague. © 2011 The Wildlife Society
Sharp‐tailed grouse lek attendance and fidelity in upper Michigan
Authors: Drummer Thomas D. , Corace R. Gregory , Sjogren Stephen J.
Published: March 2011

To assess and improve existing monitoring protocols for sharp‐tailed grouse (Tympanuchus phasianellus) in the eastern Upper Peninsula of Michigan, we used data from 58 radio‐collared grouse (46 M, 12 F) monitored within 3 openland landscape types: a xeric, conifer‐dominated site, a wetland‐dominated site, and a site dominated by low‐intensity agriculture. We used lek counts and radio telemetry to determine lek attendance rates, factors affecting lek attendance rates, lek fidelity, and inter‐sexual variation in these parameters. Our analysis indicated lek attendance varied with respect to sex of bird, day of year, time after sunrise, and wind speed. Peak male lek attendance rates exceeded those of females by up to 40%, and peak lekking activity for both males and females occurred during the second and third weeks of April. Male lekking activity occurred earlier and was sustained longer than that of females. Lekking activity was negatively related to time of day and wind speed. We observed strong lek fidelity as radio‐collared birds attended a primary lek 94% of the time, indicating a low probability of multiple counting of individual birds. We also proposed a method to adjust lek count data for the probability that birds are on a lek during lek counts. Our proposed method can be used by researchers and managers to improve estimates of the number of birds attending a lek by reducing the negative bias associated with observed counts. © 2011 The Wildlife Society.
Non‐permanent radiotelemetry leg harness for small birds
Authors: Kesler Dylan C.
Published: March 2011

I developed a modified leg harness for mounting radiotelemetry transmitters to small birds, which includes a weak link that allows telemetry equipment to be shed. Over 4 years, I mounted 62 transmitters on 49 Tuamotu kingfishers (Todiramphus gambieri) using weak‐link harnesses. Kingfishers retained 86% of transmitters for the duration of monitoring periods (23–66 days) whereas 22 of 23 transmitters were shed from birds resighted after 6–15 months. Apparent mortality was no higher for radio‐marked birds than for birds without transmitters. The weak‐link harness is an improvement to existing transmitter attachment techniques and provides a useful, effective, and ethical means of studying bird movements. © 2011 The Wildlife Society.
A component system for broadcasting sound for research and management
Authors: Farrell Shannon L. , Campomizzi Andrew J.
Published: March 2011

We designed, deployed, and evaluated a sound broadcast system for use in an experiment investigating response of songbirds to conspecific vocalizations in habitat selection; the system was functional, flexible, and allowed for easy assembly, customization, and repair. Broadcast of sound in the field can enable study of animal response to predators, conspecifics, heterospecifics, noise, and other stimuli and is being considered for a variety of management applications. However, no published method is available for building a sound broadcast system from readily available components for use in the field. © 2011 The Wildlife Society.
A preliminary study assessing risk to Tasmanian devils from poisoning for red foxes
Authors: Hughes Channing , Gaffney Robbie , Dickman Christopher R.
Published: March 2011

The recent introduction of red foxes (Vulpes vulpes) to Australia's island state of Tasmania represents a major threat to native fauna. In response, the Tasmanian government has begun a fox eradication program using Foxoff®, a bait containing the poison sodium monofluoroacetate (commonly known as 1080). The bait is potentially attractive to native Tasmanian carnivores as well as to foxes. Of particular concern is the endangered Tasmanian devil (Sarcophilus harrisii), which is already at risk from an emergent infectious disease, devil facial tumor disease (DFTD). In both a captive and a field study using non‐toxic Foxoff bait, we assessed bait palatability and possible effects of demographics, hunger level, bait age, and bait burial method on the likelihood of bait uptake by Tasmanian devils. Captive devils showed varying interest in the bait, but wild devils appeared to find it uniformly palatable. In the captive study, males and younger, captive‐born animals were more likely to excavate and remove bait. Subterranean burial at 15 cm was the most effective deterrent to bait excavation; effectiveness decreased at shallower depths and with surface‐level bait buried beneath soil mounds. Our findings suggest that the current fox‐baiting campaign may negatively impact individual devils. More extensive study is necessary to assess potential risk at the population level. © 2011 The Wildlife Society.
Estimating utilization distributions with kernel versus local convex hull methods
Authors: Lichti Nathanael I. , Swihart Robert K.
Published: March 2011

Estimates of utilization distributions (UDs) are used in analyses of home‐range area, habitat and resource selection, and social interactions. We simulated data from 12 parent UDs, representing 3 series of increasingly intense space‐use patterns (clustering of points around a home site, restriction of locations to a network of nodes and corridors, and dominance of a central hole in the UD) and compared the ability of kernel density estimation (KDE) and local convex hull (LCH) construction to reconstruct known UDs from samples of 10, 50, 250, and 1,000 location points. For KDE, we considered 4 bandwidth selectors: the reference bandwidth, least‐squares cross‐validation (LSCV), direct plug‐in (DPI), and solve‐the‐equation (STE). For the sample sizes and UD patterns tested here, KDE achieved significantly higher volume‐of‐intersection (VI) scores with known parent UDs than did LCH; KDE also provided less biased home‐range area estimates under many conditions. However, LCH minimized the UD volume that occurred outside the true home range boundary (Vout). Among the KDE bandwidth estimators, relative performance depended on the type and intensity of space use patterns, sample size, and the metric used to evaluate performance. Biologists should use KDE for UD and home range estimation within a probabilistic context, unless their objective is to exclude potentially unused areas by defining the area delimited by data. © 2011 The Wildlife Society.
Effects of sagebrush treatments on multi‐scale resource selection by pygmy rabbits
Authors: Wilson Tammy L. , Howe Frank P. , Edwards Thomas C.
Published: March 2011

The effects of widespread sagebrush removal treatments on pygmy rabbits (Brachylagus idahoensis) are not well understood. Due to reliance on sagebrush, pygmy rabbits are among the species for which these treatments may be detrimental. Our objectives were to evaluate the effects of experimental sagebrush treatment on 8 radio‐collared pygmy rabbits between and within home range habitat selection using Monte Carlo simulation from null models. Pygmy rabbits were not extirpated from plots containing habitat treatments, and we found no evidence that treatments affected home range placement. The mean treatment distance of observed home range centers did not differ from repeated trials of random points. However, we found evidence of within home range selection against treatments from 2 of 8 rabbits located close to the treatments. The mean treatment distance of all observed locations for these 2 rabbits was greater than expected based on a null model. We also used snow tracking to show that pygmy rabbits entered treatments in 4 out of 21 trials, which was less often than expected by chance (G2 = 8.662, P = 0.003). Conservatively, sagebrush removal treatments should not be conducted on active or recently active pygmy rabbit burrows. Elsewhere near known pygmy rabbit sites, treated patches should be small and connected by untreated corridors to prevent potentially limiting movement of rabbits among the untreated habitat. © 2011 The Wildlife Society.