bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear excitation profiles for three‐dimensional inflow MR angiography
Authors: Nägele Thomas , Klose Uwe , Grodd Wolfgang , Voigt Karsten , Nüsslin Fridtjof
Published: March 2007

An RF excitation pulse for three‐dimensional (3D) time‐of‐flight (TOP) MR angiography (MRA) with a nonlinear excitation profile was numerically calculated under the condition of uniform vessel signal across the excitation volume (slab), and the superiority of the optform pulse as compared with conventional RF pulses and TONE pulses was demonstrated. For this purpose we acquired MRA of the lower leg and of the carotid and vertebral arteries in a 30‐year‐old healthy volunteer. Although the flow velocity ranges in these two anatomic locations are different by about a factor of 10, in both cases the corresponding optform pulse provided the best signal homogeneity at the highest level.
Mr imaging of ventriculomegaly—a qualitative and quantitative comparison of communicating hydrocephalus, central atrophy, and normal studies
Authors: Kurihara Yoshiko , Simonson Tereasa M. , Nguyen Hoang D. , Fisher David J. , Sato Chin‐Shoou Lin Yutaka , Yuh William T. C.
Published: March 2007

Both communicating hydrocephalus and central atrophy cause ventricular dilatation. However, patients with hydrocephalus may require treatment. The aim of this study was to asscss qualitatively and quantitatively the cffcacy of MR imaging in the differentiation of communicating hydrocephalus from central atrophy. The midsagittal T1‐weighted MR images of 33 patients with communicating hydrocephalus, 31 patients with central atrophy, and 23 normal objects were evaluated qualitatively and quantitativly. This included configuration of the aqueduct; area of the sep‐tum pellucidum, third ventricle, and fourth ventricle; and morphology of the corpus callosum. Distal dilatation of the aqueduct was detected in 33.3% of patients with communicating hydroccphalus and in none of those with central atrophy. The corpus callosum was elevated in patients with communicating hydrocephalus when compared with that in patients with central atrophy. In conclusion, an analysis of midsagittal T1‐ weighted images has identified useful qualitative and quantitative criteris in the differentiation of communicating hydrocephalus from central atrophy. The configuration of the aqueduct with funneling at the fourth ventricular end strongly suggests the presence of communicating hydrocephalus rather than central atrophy alone.
Effects of MR exposure on akonal outgrowth in the sympathetic nervous system of the chick
Authors: Yip Yee Ping , Capriotti Christine , W. Y Joseph
Published: March 2007

The effects of MR exposure on the rate and specificlty of sympathetic preganglionic axonal outgrowth were examined in the chick embryo. Embryos were exposed to a static magnetic field of 1.5 T for 6 hours, 64 MHt RF field pulses, and a Switched magnetic field gradient of amplitude 0.6 G/cm for 4 hours. No significant difference in axonal outgrowth wm observed between MR‐exposed and control embryos. In addition. the distributionr of several major extracellular matrix (ECM) molecules, lpmlnln, fibronectin, and collagen N, were examined. Immunoetaining patterns of these ECM molecules duxing axonal outgrowth showed no difference between MR‐expored and control embryos. Our results suggert that the MR erporure conditions used in this study do not affect axonal outgrowth in the sympathetic nervous system of the chick.
Mr assessment of posttraumatic flexion contracture of the elbow
Authors: Fortier Marielle V. , Forster Bruce B. , Pinney Stephen , Regan William
Published: March 2007

Reoperative assessment of posttraumatic flexion contracture of the elbow includes plain radiographs and tomograms, which are dif0cult to obtain in the coronal plane due to the contracture. We conducted this study to determine the uaefulness of MR haghg in the work‐up of these patients. Twelve patients with flexion contracture of the elbow were studied. In addition to standard spin‐echo sequences, a sagittally acquired spoiled gradient‐recalled echo 3D data set of the flexed elbow was obtained and reformatted coronally using a curved plane of reconstruction. The MR hdings were compared to the plain filmrr. tomograms and surgical results. MRI allowed identification of loose bodies that were sometimes poorly visualized, or not seen. on plain films, and demonstrated degenerative changes eqdy as well M tomograms. MR showed soft tissue abnormalities including capsular and collateral ligament thickening. Cwillnear reconstructions were helpful in the assessment of collateral ligaments in patients with severe contractures. We conclude that MR is useful in the evaluation of elbow flexion contractures. particularly in assessing soft tissue causes.
Hr imaging and vascular access ports: Ex vivo evaluation of ferromagnetism, heating, and artifacts at 1.5 t
Authors: Shellock Frank G. , Nogueira Marcia , Morisoli Stacy
Published: March 2007

The purpose of our study was to asacsa Futomagneh. hating. ad artifactr, associated with vabcular access ports exposed to a 1.5‐T MR system. Tweaty‐cight different vabcular access port. were evaluated in thb investlgation. Fmmagnetism was determined by using two previouely de techniques. Temperature changes were measured immediately before and after performing a pulse sequence on the vascular access port6 for 80 min at a speciflc absorption rate of 3.1 W/kg. Artifacts were assessed h aesoclation with the use of a fht CRASS pulse sequence. None of the vascular access ports displayed ferromnlpletim. Heating was 0.2°or less. The prerence of adhcts varied. depending on the component materials. The Lack of fcrromagnetiam and negligible heating indicates that MR imaging performed at 1.6 T or lees may be conducted dely in patients with any of the vascular access port. tested. None of the associated artifacts produced by the vascdar access port. is comddercd to paw a rubsttantial problem for MR imaging.
Acute occlusive ischemia of the rat intestine: Early detection by MR imaging with polylysinemgd‐dtpa enhancement
Authors: Van Beers Bernard E. , Mottet Isabelle , Delos Monique , Goudemant Jean‐Franpis , Demeure Roger , Pringot Jacques
Published: March 2007

The purpose of this study was to assess the potential role of MR h@ng with polylysine‐Gd‐DTPA enhancement in the early detection of acute occlusive inteetinal ischemia in a rat model. After deveecularhtion Of the distal ileum in 12 rats. T2‐Weighted fart spinecho MR images were acquired, followed by T1‐ weighted imagea before and after IV administration of 0.1 mmol/kg polylysine‐Gd‐DTPA. The signal intensity of the ischemic intestine did not differ signiflcantly from that of the normal intestine before the admlnistration of the contrast material. No mucoeal or submucosal edema or hemorrhage was found in the ischemic intestine at histologic examination. After the administration of polylysine‐Gd‐DTPA, the ischemic intestine lacked enhancement and its signal intensity was significantly lower than that of the normal inteatine. MR imaging with polylysine‐Gd‐DTPA enhancement can detect acute occlusive ischemia of the rat intestine at an carly stage.
Superparamagnetic Iron Oxide Hepatic MR Imaging: Efficacy and Safety Using Conventional and Fast Spin‐Echo Pulse Sequences
Authors: Schwartz Lawrence H. , Seltzer Steven E. , Tempany Clare M. C. , Silverman Stuart G. , Piwnica‐Worms David R. , Adams Douglass F. , Herman Lee , Herman Lisa A. , Hooshmand Roshann
Published: March 2007

The purpose of this study was to evaluate the technical efficacy and safety of iv ferumozldes (Feridexa), a superparamagnetic iron oxide contrast agent for detection of hepatic lesions using conventional spin‐echo and fast spin‐echo MR images. Precontract and postcontrast MR studies were performed on 25 patients with suspected focal hepatic lesions. Conventional Tl‐and T2‐weighted MR images, as well as fast spin‐echo and fat suppressed fast spin‐echo MR images, were evaluated. Quantitative assessment of the contrast agent was performed obtaining region of interest measurements of the liver, spleen, and selected hepatic lesions. The pulse sequences were also evaluated subjectively for overall image quality and a subjective assessment of lesion detection. The use of a superparamagnetic iron oxide contrast agent led to a decrease in hepatic signal intensity on all pulse sequences. Lesion‐to‐liver contrast increased 41.1%, 36.5%, and 32.0% on the conventional T2, fast spin‐echo, and fat suppressed fast spin echo pulse sequences, respectively. Lesion‐to‐liver contrast decreased on the T1‐weighted postcontrast pulse sequence by 23.8%. Despite Improvement in lesion‐to‐liver contrast, radiologists subjectively preferred the precontract sequences because of overall better image quality. At a dose of 10 μmol/kg, fenunoxides favorably impacts lesion‐to‐liver contrast, and may be useful in hepatic imaging, more with conventional T2‐weighted spin‐echo pulse sequences than with T2‐weighted fast spin‐echo pulse sequences.
Comparison of Ultrasound, CT, and MR Imaging in the Evaluation of Candidates for TIPS
Authors: Kraus Barry B. , Ros Pablo R. , Abbitt Patricia L. , Kerns Scott R. , Sabatelli Frank W.
Published: March 2007

To compare ultrasound (US), CT, and MRI in the evaluation of hepatic vascular anatomy, portal and splenic venous flow, and collateral pathways (varices and spontaneous shunts) in candidates for transjugular intrahepatic portosystemic shunting (TIPS), 17 patients with history of refractory variceal bleeding or intractable ascites underwent duplex US, contrast‐enhanced CT, and MRI before TIPS. The appearance of portal and hepatic anatomy was graded from 1 (not visible) to 4 (excellent visualization) independently by four radiologists. Presence and direction of portal and splenic venous flow, and presence and location of varices and spontaneous portosystemic shunts were also assessed. Results and effects of interobserver variation were assessed for significance using Friedman's ANOVA and Wilcoxon's signed‐rank test. MRI yielded higher scores than CT or US for hepatic veins (P <.0001) and inferior vena cava (P <.0001). MRI and CT scored better than US for portal vein branches (P =.012) and splenic vein (P =.0038). All tests demonstrated the main portal vein well, with no statistically significant difference. US and MRI were more sensitive than CT for detecting portal vein flow and direction (US 76%, CT 0%, MRI 82%). MRI was most sensitive for splenic vein flow and direction (US 41%, CT 0%. MRI 76%). CT and MRI were more sensitive than US in detecting varices (US 5%, CT 50%, MRI 58%) and spontaneous shunts (US 13%, CT 75%, MRI 75%). Interobserver variation did not influence results significantly P =.3691). MRI provides the most useful information and may be the preferred single imaging test prior to TIPS.
Validation of volume flow measurements with cine phase‐contrast MR imaging for peripheral arterial waveforms
Authors: McCauley Thomas R. , Pena Constantino S. , Holland Christy K. , Price Thomas B. , Gore John C.
Published: March 2007

A flow phantom was used to study MR volume flow measurements for monophasic and triphasic waveforms over the flow range expected in peripheral arteries at rest and with exercise (2–24 mL/sec, n = 50). The improvement in accuracy with phase‐correction image processing to eliminate errors caused by eddy currents was measured. Volume flow estimates with Doppler sonography were also measured. MR volume flow measurements correlated with volume collection with r = 0.996 and mean error = 4.6%. Phase–correction processing decreased mean error from 12.6% to 4.6% (P <.001, paired t‐test). Doppler sonography had a higher mean error of 10.3% (P <.001, unpaired t‐test). Cine phase‐contrast MR imaging provides accurate estimates of volume blood flow for waveforms and flow ranges expected in peripheral arteries.
Cocaine‐induced changes in time course of regional cerebral blood volume and transit time as determined by dynamic MR imaging
Authors: Li Ka‐Loh , Suojanen James N.
Published: March 2007

We examined cocaine‐mediated changes in regional cerebral blood volume (rCBV) and mean transit time (MTT) in central brain structures of rats using functional MR imaging techniques. Changes in MTT and rCBV in animals who had previously been given cocaine depended on the length of time between the last pretreatment injection and the acute injection and seemed to parallel cocaine‐mediated changes in extracellular dopamine concentrations.
Mr imaging of hepatic nodular regenerative hyperplasia
Authors: Siegelman Evan S. , Outwater Eric K. , Furth Emma E. , Rubin Raphael
Published: March 2007

Nodular regenerative hyperplasia (NRH), a rare condition that is commonly associated with noncirrhotic portal hypertension, is not well described in the MR literature. Three patients at two institutions were identified who had both abdominal MR imaging and pathologic evidence of NRH. All examinations were performed at 1.5 T and included axial T1‐ and T2‐weighted spin‐echo (SE) images. The MR studies were reviewed by two radiologists in consensus. Two patients had multiple liver lesions that had high signal components on T1‐weighted images and were predominantly isointense with liver on the T2‐weighted images. One patient had no focal lesions identified. NRH, when visualized on MR images, appears as multifocal masses with shortened Tl and T2 similar to liver. NRH should be considered in the differential diagnosis of hepatocellular tumors, especially in patients with a predisposing condition.
Visualizing tissue compliance with MR imaging
Authors: Plewes D. B. , Betty I. , Urchuk S. N. , Soutar I.
Published: March 2007

We propose a method for visualizing the mechanical properties of tissue based on the use of periodic mechanical compression in conjunction with phase‐contrast MR imaging. A specialized mechanical transducer was used to provide programmable compression pulses to the surface of compliant phantoms. These compression pulses were synchronized to a spin‐echo sequence with motion‐sensitizing gradients to generate phase information reflecting spin displacement throughout the phantom. This sequence was tested with two agarose gel phantoms. The first was a cylinder containing three parallel layers of varying compliance and the second was composed of a semirigid sphere suspended in a uniform layer of decreased elastic modulus. Images showed complex patterns of motion throughout the phantom, which correlated with expected motion behavior of the phantom structures. This indicates that the biomechanical properties of tissues may be elucidated through the use of motion‐sensitized MR imaging and suggests that a form of image contrast relating to tissue elasticity may be feasible.
Automated shimming at 1.5 t using echo‐planar image frequency maps
Authors: Reese Timothy G. , Davis Timothy L. , Weisskoff Robert M.
Published: March 2007

Using echo‐planar imaging, we developed an automated image‐based procedure to shim the static (B0) field. Our method uses the rapid acquisition capability of echo‐planar Imaging to collect the required frequency data rapidly, rendering the shim data acquisition time negligible in comparison with the total study time. We address image distortion issues involved in echo‐planar imaging acquisition of the data and formulate analytic methods for arriving at an optimal shim for the NMR imaging experiment in a single iteration. We investigated the use of cost functions other than least‐squares (Chebychev, high‐order numeric) and found that choice between the cost functions we tested was irrelevant to resultant image quality, at least when used in conjunction with low‐order shims. With appropriate integration, the method has become routine practice for investigators at our laboratory.
Functional MR imaging using gradient‐echo echo‐planar imaging in the presence of large static field inhomogeneities
Authors: Constable R. Todd
Published: March 2007

At 1.5 T, the field strength of most clinical MR imagers, gradient‐echo Imaging Is the primary imaging method for measuring brain activation, as such sequences are highly sensitive to changes in blood oxygenation or T2* effects. Unfortunately, gradient‐echo sequences are also extremely sensitive to magnetic field inhomogeneities, and this sensitivity has precluded examination of regions of cortex near field inhomogeneities with functional MR imaging. This article presents a gradient‐echo echo‐planar imaging method that uses variable amplitude scaling on the slice‐select refocusing lobe to generate images compensated for static field inhomogeneities. A technique for constructing composite Images to be used in statistical tests for activation is also presented. The method is shown to produce clean activation maps in the presence of large static field inhomogeneities. The technique retains the sensitivity of gradient‐ echo imaging to changes in blood oxygenation while removing the sensitivity to large static field inhomogeneities.
Fat suppression at 7t using a surface coil: Application of an adiabatic half‐passage chemical shift selective radiofrequency pulse
Authors: Yongbi Martin N. , Ding Shujun , Dunn Jeffrey F.
Published: March 2007

The selective suppression of fat using chemical shift selective (CHESS) sinc, gaussian presaturation, or binomial radiofrequency pulses are widely implemented techniques in magnetic resonance imaging. For applications wherein transmitter coils that generate inhomogeneous magnetic (B1) fields are used (eg. surface coils), adlabatic radiofrequency pulses that are less susceptible to spatial variations in B1 amplitude will improve the spatial homogeneity of spin excitation angle. Herein, we describe the application of an adiabatic half‐passage hyperbolic secant CHESS pulse suitable for acquiring fat‐suppressed magnetic resonance images with surface coils on high‐field systems. Images obtained from a water/fat phantom and from the abdominal region of a rat are presented indicating excellent suppression of fat signal from the entire coil‐sensitive volume.
Giant cell tumor of the tendon sheath in the ankle: MRI with pathologic correlation
Authors: Narra Vamsidhar R. , Shirkhoda Ali , Shetty Anil N. , Bis Kostaki G. , Armin Ali‐Reza , Gurgun Mehmet
Published: March 2007

We report a case of Giant cell tumor of the tendon sheath involving the ankle, wherein spin‐echo (T1‐ and T2‐weighted). gradient‐echo, and dynamic contrast‐enhanced sequences were performed, and the tumor was noted to be very vascular. To the best of our knowledge, the use of gradient‐echo sequences and the pattern of enhancement by time‐intensity curves has not been reported earlier.
Effect of flaxseed and wheat flour blends on dough rheology and bread quality
Authors: Koca A Faik , Anil Munir
Published: March 2007

The rheological and baking properties of flaxseed/wheat composite flours were studied. Flaxseed flour was used to replace 50, 100, 150 and 200 g kg−1 of wheat flour in bread. Farinographic studies showed that water absorption, dough development time and mixing tolerance index increased as the amount of flaxseed flour increased, while dough stability decreased at 100, 150 and 200 g kg−1 of flaxseed flour substitution. The extensographic energy of dough also decreased at 150 and 200 g kg−1 flaxseed levels. The addition of increasing amounts of flaxseed flour caused a decrease in extensibility. Doughs containing 100, 150 and 200 g kg−1 flaxseed flour showed resistance to extension comparable to that of control dough. The specific volume of flaxseed flour breads was similar to that of control bread. Crust L, a, b values of breads with flaxseed flour were lower than those of control bread. Breads with flaxseed flour gave lower crumb L and b values and higher a values than control bread. The sensory properties showed that an acceptable bread could be produced using flaxseed flour up to a level of 200 g kg−1. Copyright © 2007 Society of Chemical Industry
Effects of fermentation time and storage on the water‐soluble vitamin contents of tarhana
Authors: Certel Muharrem , Erbaş Mustafa , Uslu Mustafa K , Erbaş Mediha O
Published: March 2007

Changes in water‐soluble vitamins were investigated in tarhana dough during fermentation and in tarhana stored under a variety of conditions for up to 6 months. The contents of riboflavin (P < 0.01), thiamin, niacin, vitamin B6 and folic acid (P < 0.05) increased significantly during fermentation. The thiamin, riboflavin, niacin, vitamin B6 and folic acid contents of tarhana dough were 4.80, 1.85, 7.68, 15.30 and 2.25 mg kg−1 respectively at the beginning of fermentation and increased to 10.15, 5.15, 24.04, 19.35 and 6.10 mg kg−1 respectively at the end of fermentation. Thiamin, riboflavin and folic acid contents were significantly affected (P < 0.01) by storage type and period, but niacin and vitamin B6 contents were not affected (P > 0.05). The water‐soluble vitamin contents of tarhana stored wet were higher than those of tarhana stored dry. Drying resulted in a 24% reduction in riboflavin content and an 86% reduction in folic acid content. Copyright © 2007 Society of Chemical Industry
Size‐selective junctional barrier and Ca2+‐independent cell adhesion in the testis of Cynops pyrrhogaster: Expression and Function of Occludin
Authors: Jin Yuji , Uchida Ichiro , Eto Ko , Kitano Takeshi , Abe Shin‐ichi
Published: March 2007

In urodeles which has testicular structure different from that in mammals, blood–testis barrier was reported to exist like in mammals. However, molecular and functional analyses of the components of the blood–testis barrier in urodeles have not been reported yet. Toward elucidation of the barrier functions and their molecular components in newt testis, we aimed to isolate occludin cDNAs and obtained two kinds of occludin partial cDNAs (occludin 1 and 2) encoding the putative second extracellular loop. Immunoblot and immunofluorescence studies using antibodies against peptides each corresponding to a part of the second extracellular loop of occludin 1 and 2, and those against β‐catenin and zonula occludens‐1 (ZO‐1) showed that occludin, as well as β‐catenin and ZO‐1, was expressed not only in Sertoli cells but also in germ cells throughout all the stages from spermatogonia to elongate spermatids. Tracer experiments revealed a size‐selective barrier which allows small molecules (∼500 Da) to get into cysts through Sertoli cells' barrier, but not larger ones (>1.9 kDa) in the stages from spermatogonia to almost mature sperm. No occludin peptides corresponding to a part of the second extracellular loop destroyed the junctional barrier, while both the peptides and antibodies significantly inhibited reaggregation of the dissociated testicular cells which was to a large extent Ca2+‐independent. These results indicate that the second extracellular loop of occludin is involved in cell adhesion rather than in size‐selective barrier in newt testis, though the possibility cannot be excluded that the peptides were not long enough to inhibit the barrier function. Mol. Reprod. Dev. 75: 202–216, 2008. © 2007 Wiley‐Liss, Inc.
Dax1 suppresses P450arom expression in medaka ovarian follicles
Authors: Nakamoto Masatoshi , Wang De‐Shou , Suzuki Aya , Matsuda Masaru , Nagahama Yoshitaka , Shibata Naoki
Published: March 2007

Dax1 is a member of an unusual orphan nuclear receptor family, and is known to regulate P450arom in mammals and is involved in sex differentiation in some vertebrates. To investigate whether Dax1 is involved in the regulation of the steroidogenic pathway for estrogen biosynthesis in medaka ovarian follicles, we isolated Dax1 cDNA from adult medaka ovaries and analyzed its expression pattern in medaka gonads. In adult ovaries, Dax1 mRNA was detected only in postvitellogenic follicles and was not detected in previtellogenic and vitellogenic follicles. In adult testis, Dax1 mRNA was not detected. We compared the expression pattern of Dax1 with that of Foxl2, Ad4BP/Sf‐1, P450c17, and P450arom by in situ hybridization using adjacent sections. In contrast to Dax1 expression, these genes were co‐expressed in vitellogenic follicles but were not detected in postvitellogenic follicles. Thus, in medaka ovarian follicles, Dax1 did not show any overlapping expression patterns against Foxl2, Ad4BP/Sf‐1, P450c17, and P450arom. Moreover, co‐transfection experiments demonstrated that Dax1 inhibits Ad4BP/Sf‐1‐ and Foxl2‐mediated P450arom expression. On the other hand, during early sex differentiation, Dax1 mRNA was not detected in both males and females. Our results suggest that Dax1 down‐regulates Ad4BP/Sf‐1‐ and Foxl2‐mediated P450arom expression in medaka ovarian follicles. Mol. Reprod. Dev. 74: 1239–1246, 2007. © 2007 Wiley‐Liss, Inc.
Effects of fetal calf serum, phenazine ethosulfate and either glucose or fructose during in vitro culture of bovine embryos on embryonic development after cryopreservation
Authors: Barceló‐Fimbres M. , Seidel G.E.
Published: March 2007

This study investigated effects of hexoses, fetal calf serum (FCS), and phenazine ethosulfate (PES) during the culture of bovine embryos on blastocyst development and survival after cryopreservation by slow freezing or vitrification. The basal, control medium was chemically defined (CDM) plus 0.5% fatty acid‐free BSA. In vitro‐produced bovine zygotes were cultured in CDM‐1 with 0.5 mM glucose; after 60 hr, 8‐cell embryos were cultured 4.5 days in CDM‐2. The 8‐cell embryos were randomly allocated to a 2 × 3 × 2 × 3 factorial experimental design with two energy substrates (2 mM glucose or fructose); three additives (0.3 µM PES, 10% FCS, and control); two cryopreservation methods using no animal products (conventional slow freezing or vitrification); and semen from three bulls with two replicates for each bull. A total of 1,107 blastocysts were produced. Fructose resulted in 13% more blastocysts per oocyte than glucose (37.2% vs. 32.9%), and per 8‐cell embryo (51.3% vs. 45.3%; P < 0.01). No differences were found for additives (P > 0.1) control, FCS, or PES for blastocysts per oocyte or per 8‐cell embryo. There was a significant interaction (P < 0.05) between additives and hexoses for blastocyst production; although trends were similar, the benefit of fructose compared to glucose was greater for controls than for FCS or PES. Culture of embryos with PES, which reduces cytoplasmic lipid content, improved cryotolerance of bovine embryos; post‐cryopreservation survival of blastocysts averaged over vitrification and slow freezing (between which there was no difference) was 91.9%, 84.9%, and 60.2% of unfrozen controls (P < 0.01) for PES, control, and FCS groups, respectively. Mol. Reprod. Dev. 74: 1395–1405, 2007. © 2007 Wiley‐Liss, Inc.
Analysis and discussion of Anycast scalability in IPv6
Authors: Wang Xiaonan , Qian Huanyan
Published: March 2007

The existing designs for providing Anycast services are either to confine Anycast groups to a preconfigured topological region or to globally distribute Anycast groups across the whole Internet. The latter causes the routing tables to grow proportionally to the number of global Anycast groups in the entire Internet and both of the above designs restrict and hinder the application and development of Anycast services. In this paper a new kind of Anycast communication model is proposed on the basis of Anycast tree technology. Since this model adopts a dynamic Anycast group, allowing Anycast members to freely leave and join the Anycast group, it radically solves the existing scalability problem. In addition, this model accomplishes the distributed maintenance and transaction of Anycast service requests and information on the Anycast tree; thus it performs load balance. This paper analyzes and discusses the feasibility and validity of the communication model; the experimental data in IPv6 simulation demonstrate that the total response time of one Anycast service (e.g., file downloading) acquired through this communication model is shorter by 15% than that through the current communication model. Copyright © 2007 John Wiley & Sons, Ltd.
The HUPO Pre‐Congress Proteomics Standards Initiative Workshop HUPO 5th Annual World Congress Long Beach, CA, USA 28 October–1 November 2006
Authors: Orchard Sandra , Jones Andrew R. , Stephan Christian , Binz Pierre‐Alain
Published: March 2007

The plenary session of the Proteomics Standards Initiative of the Human Proteome Organisation provided an opportunity to update delegates on the progress of the work of the Human Proteome Organisation's Proteomics Standards Initiative (HUPO‐PSI) to develop and implement standards in the field of proteomics. Significant advances have been made since the previous congress, with several of the interchange standards and minimal requirements documents being submitted for publication in the literature and being more widely adopted by both manufacturers and data repositories. An exciting development over the interim twelve months is the ongoing merger of the two existing mass spectrometry standards, the PSI mzData and Institute for Systems Biology mzXML, into a single product. This should be achieved by early in 2007.
Synthesis and properties of novel electrophosphorescent polymers from quinoline‐ and pyridine‐end‐capped polyfluorenes with rhenium(I) chromophores
Authors: Lee Po‐I , Hsu Steve Lien‐Chung
Published: March 2007

Novel electrophosphorescent polymers were prepared from quinoline‐ and pyridine‐end‐capped polyfluorenes reacted with 4,4′‐dimethyl‐2,2′‐bipyridyl (tricarbonyl)rhenium(I) chloride. Fourier transform infrared and photoluminescence spectroscopy confirmed that the rhenium complex was successfully incorporated into the polymer backbones. The energy transfer could be reached by an efficient intramolecular process. The emission contributions of the polyfluorene and organic complex were found from the electroluminescence spectra. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1492–1498, 2007
Bronchodilator response during acute viral bronchiolitis in infancy
Authors: Soto Manuel E. , Sly Peter D. , Uren Eric , Taussig Lynn M. , Landau Louis I.
Published: March 2007

Bronchodilator responsiveness was assessed by measuring specific respiratory conductance before and after inhalation of aerosolized bronchodilator in 50 infants who had acute bronchiolitis due to respiratory syncytial virus infection. Thirty per cent of the infants showed an improvement in specific conductance. Responders could not be differentiated from nonresponders by family histories of atopy, eosinophil counts, or immunoglobulin levels in blood and nasal secretions. Eighty‐three per cent of the families and 54% of the mothers of the infants were smokers. Babies of smoking mothers had lower specific conductances than did those of nonsmoking mothers but showed no differences in bronchodilator response. The clinical significance of this bronchodilator‐responsive subgroup has yet to be defined.
Ultrastructure of the bronchial epithelium in three children with asthma
Authors: Konrádová V. , Čopová C. , Suková B. , Houštěk J.
Published: March 2007

The ultrastructure of the bronchial epithelium of three asthmatic girls was studied from material obtained during bronchoscopy. In all patients the large bronchi were lined with an altered pseudostratified ciliated epithelium having a severely damaged ciliary border. Injury to the ciliated cells was manifested by apical bleb formation, destruction of free kinocilia, pathological ciliogenesis, dilation of the spaces of the endoplasmic reticulum and Golgi complex, an increase in the number of vacuoles and lysosomes, and the appearance of altered mitochondria. The most outstanding feature of the epithelium was the marked hyperplasia of the goblet cells with the development of intraepithelial mucous glands. The mucous elements of the epithelium had discharged their mucus. Further, there were signs of mucus cell injury and degeneration. Squamous metaplasia of the pseudostratified epithelium was not observed.
Breathing pattern of neonates during nonnutritive sucking
Authors: Mathew Oommen P. , Clark Mark L. , Pronske Maria H.
Published: March 2007

Alteration of the breathing pattern seen during oral feeding has been attributed to the behavioral activity of sucking, repeated swallowing, and laryngeal chemoreceptor stimulation. Because it preserves the behavioral activity of sucking but eliminates the laryngeal chemoreceptor stimulation and repeated swallowing that occurs during nutritive sucking, the effects of nonnutritive sucking was evaluated in 19 term infants. The suck‐pause pattern seen during nonnutritive sucking is similar to that of nutritive sucking. None of the variables measured (inspiratory duration, expiratory duration, breathing frequency, and tidal volume) were significantly altered during the overall period of nonnutritive sucking when compared with previously obtained control values. These results suggest that the alteration of breathing pattern observed during oral feeding cannot be accounted for by the behavioral activity of sucking per se. However, when the sucking phases of the nonnutritive period were compared with the intervening pauses, a reduction in the expiratory duration (P < 0.05) and a reduction in tidal volume (P < 0.05) were observed. Thus, the breathing pattern of human neonates is indeed altered during the sucking phase of the nonnutritive period; pressure changes associated with sucking may account for this alteration.
Clinical applications of ultrathin flexible bronchoscopes
Authors: Wood Robert E.
Published: March 2007

Three different models of ultrathin flexible fiberoptic bronchoscopes (1.8, 2.3, and 2.7 mm in diameter) were used in 190 examinations of pediatric patients. These instruments facilitate clinical procedures and evaluations that are difficult if not impossible with previous bronchoscopes. New applications include endoscopic transnasal intubation with endotracheal tubes as small as 3.0 mm (ID), inspection of the upper lobe segments in infants weighing less than 2.5 kg, and evaluation of the lower airways through endotracheal tubes as small as 2.5 mm (ID) or tracheostomy tubes as small as no. 00 (3.1 mm ID). Although these instruments have no suction channel and are thus incapable of removing airway secretions or obtaining specimens, they are extremely useful for many clinical purposes in infants and young children.
The effects of air pollution on the respiratory health of children: A cross‐sectional study
Authors: Spinaci S. , Arossa W. , Bugiani M. , Natale P. , Bucca C. , de Candussio G.
Published: March 2007

To investigate the effects of air pollution on the respiratory health of children, a subject of some controversy, a comparative study was undertaken of 2,385 school children who lived in central urban, peripheral urban, and suburban areas. Daily monitoring of sulphur dioxide and total suspended particle concentrations in all areas showed that pollutant concentrations in central and peripheral urban areas were above commonly accepted safety levels for respiratory health, while concentrations in the suburban area were within acceptable limits. A questionnaire administered to each mother assessed environmental exposure to pollutants in the household, the occurrence of respiratory symptoms as well as lung diseases as diagnosed by a physician, and general information. Children were interviewed about smoking habits and any acute respiratory symptoms. Children also performed standard lung function tests. Results showed that children from both urban areas had lessened pulmonary function and a higher prevalence of bronchial secretion with common colds than did those from the suburban area. These differences persisted after corrections for exposure to indoor pollutants, active or passive smoking, socieconomic status, and sex. Parental cigarette smoking was related to a fall in forced expiratory volume in 1 second and an increased incidence of acute respiratory illnesses and chronic cough in children. Although boys had higher lung volumes and lower air flow, regression analysis showed no significant influence of the interactions “sexgeographic area” and “sex‐smoking” on lung function. It was concluded that air pollution has a significant effect on the respiratory health of children. (Key words: active and passive smoking; respiratory health of children; sulphur dioxide; total suspended particle conc.;
urban vs suburban air pollution.) Pediatr Pulmonol 1985; 1:262‐266.
Observations on the limitations of two apnea/respiration monitors commonly used in the home
Authors: Macfadyen U. M. , Simpson H.
Published: March 2007

The performance of two types of respiration monitor was studied with regard to detection of central apnea and individual breaths. Each monitor detected central apnea more frequently than routine intermittent nursing observation. Both false alarms, when the monitor failed to detect breathing movements (false positive for apnea), and false respiration signals, when the monitor failed to detect the absence of breathing movements (false negative for apnea) were found. The latter sometimes prevented alarms. It was found that a trial period of monitoring under the controlled conditions described permitted adjustments to be made which eliminated or minimized these sources of error. This should be considered when the monitors are issued for use in the home. It is important that persons issuing the monitors be aware of their limitations.
The delivery of therapeutic aerosols through endotracheal tubes
Authors: Ahrens Richard C. , Ries Rebecca A. , Popendorf William , Wiese James A.
Published: March 2007

We used an in vitro model system to examine the sites of deposition of aqueous therapeutic aerosols administered through 3‐mm, 6‐mm, and 9‐mm endotracheal tubes (commonly used in infants, children, and adults) at clinically relevant inspiratory flow rates. Aerosol was delivered to the endotracheal tube via a “T” piece and a 90° elbow. Aerosol exiting the endotracheal tube passed through an appropriately sized Plexiglas model of the trachea and mainstem bronchi, and then into an 80‐liter bag. Aerosol deposited in the “T” and elbow, endotracheal tube, large airway model, and collection bag was quantitated separately using 0.1% uranine as a tracer. Study of a conventional aerosol typical of those in common clinical use (aerodynamic mass median diameter = 3.95 μm) showed that most of the aerosol delivered into each endotracheal tube was deposited before leaving the mainstem bronchi. Substitution of an alternative nebulizer that produced a much smaller aerosol particle size (aerodynamic mass median diameter = 0.54 μm) dramatically decreased aerosol deposition in the “T” and elbow, endotracheal tube, and large airway model, and increased the quantity of aerosol penetrating beyond the mainstem bronchi up to ninefold. The mass median particle diameter of the conventional aerosol was reduced during endotracheal tube and large airway passage by poorly defined aerodynamic mechanisms that selectively removed larger particles. The smaller submicron aerosol was not similarly affected. Thus, conventional therapeutic aerosols appear to penetrate poorly through endotracheal tubes. Use of smaller particle size aerosols in treatment of intubated patients may be an effective way to circumvent this problem.
Diagnostic implications and treatment of massive spontaneous atelectasis in childhood
Authors: MÜLler Wolfgag , Hardt Horst Von Der , Rieger Christian H. L.
Published: March 2007

During a 5‐month period five children were treated for spontaneously occurring massive lung atelectasis. In three patients the underlying disease was bronchial asthma; in one patient idiopathic plastic bronchitis; and in another patient, infection with anaerobic Corynebacteria may have been a contributing factor. Types I and III hypersensitivity reactions were not considered to be likely causal factors. The clinical manifestations and management of this relatively rare event are described.
Intralobar pulmonary sequestration (a nonentity?)
Authors: Holder Pamela D. , Lansston Claire
Published: March 2007

Intralobar pulmonary sequestration has generally been considered a congenital malformation in which an accessory lung bud develops, is enveloped by normal lung, and retains its systemic arterial supply. Also usually included in the “sequestration spectrum” are aberrant arteries to normal lung with either normal or anomalous venous connection. We reviewed all surgical pathology specimens and autopsies performed at Texas Children's Hospital from 1955 through 1984. There were 15 cases with an aberrant systemic artery to normal or abnormal lung. Nine were cases of structurally normal lung with an aberrant systemic artery, and five were cystic adenomatoid malformations with a systemic artery. In one older child some features of intralobar sequestration were present, but a major bronchial connection was retained. We propose that most intralobar sequestrations represent either cystic adenomatoid malformations that clinically are unrecognized until they become secondarily infected or developmentally normal lung supplied by a systemic artery.
Liposyn infusion increases plasma prostaglandin concentrations
Authors: Hunt Carl E. , Pachman Lauren M. , Hageman Joseph R. , Cobb Michael A. , Klemka Linda
Published: March 2007

To determine whether Liposyn infusion results in increased plasma prosta‐glandin (PG) concentrations, the following study was performed in 33 adult rabbits with chronically implanted arterial and venous catheters. Plasma PG concentrations were determined by radioimmunoassay for two vasodilators, PGE2 and PGI2 (as measured by its metabolite 6‐keto‐PGF1α), and two vasoconstrictors, thromboxane (TX) A2, and PGF2α, as measured by their metabolites TXB2 and PGF2α‐M, respectively. A 1‐hour infusion of Liposyn at 4 ml per kg resulted in statistically significant increases in arterial and venous concentrations of PGE2 and 6‐keto‐PGF1α (p < 0.001) and of TXB, (p < 0.04). There were no significant changes in PGF2α‐M plasma concentrations. Liposyn infustion also resulted in a small but statistically significant increase in Pao2 of 4.7 ± 1.5 torr (p < 0.01). It is concluded that Liposyn infusion results in statistically significant increases in plasma concentrations of PGE2, 6‐keto‐PGF1α, and TXB2.
Management of children hospitalized for laryngotracheobronchitis
Authors: Wagener Jeffrey S. , Landau Louis I. , Olinsky Anthony , Phelan Peter D.
Published: March 2007

During a 12‐month period, 527 consecutive admissions for laryngotracheobronchitis (LTB) were reviewed to determine the epidemiology of hospitalized LTB patients and to better define patients who may benefit from therapy other than close observation. Viral cultures were obtained in 442 patients and were positive in 70%. Disease severity at the time of admission was unrelated to patient age or sex. Duration of hospitalization, however, was inversely related to age (p < 0.001). Laboratory investigations were rarely abnormal or of therapeutic value. Patients who on admission had stridor without sternal and chest wall retractions recovered rapidly and spontaneously; they were frequently discharged within 48 hours and never required artificial airways. Children who had sternal and chest wall retractions on admission experienced longer hospitalizations, frequently received medical intervention such as aqueous mist therapy or racemic epinephrine, and had a 6% risk of requiring artificial airway support. This group of children should be studied selectively for the benefits of specific medical therapies and diagnostic evaluations.
Alterations in plasma amino acid levels in children with asthma: A preliminary investigation
Authors: Inselman Laura S. , Khan Farida , Evans Hugh E.
Published: March 2007

Concentrations of plasma amino acids and cortisol were measured in 27 children with status asthmaticus, moderate, or mild asthma and in 7 controls without lung disease. Individuals with conditions potentially altering amino acid levels were excluded. Measurements were made at 8 A.M. and 4 P.M. on the same day. Of the 24 amino acids analyzed, threonine, serine, citrulline, tyrosine, proline, alanine, cystine, isoleucine, ornithine, lysine, and arginine were decreased at 8 A.M. or 4 P.M. and plasma cortisol was elevated at 4 P.M. in patients with status asthmaticus when compared with the other groups (p < 0.05). Normal diurnal variations of amino acids and cortisol were preserved in all groups. Sequential daily determinations in eight patients with status asthmaticus showed progressive increases in total and many individual amino acids as symptoms subsided. These studies demonstrate a decrease of certain gluconeogenic amino acids in the plasma in status asthmaticus. This diminution could reflect the need for maintenance of normal glucose concentrations in status asthmaticus. The decrease in gluconeogenic amino acid levels may play a role in the severity of asthma.
Airway hyperreactivity and a history of clinical manifestations of asthma in childhood
Authors: Mark John D. , McBride John T. , Brooks John G. , McConnochie Kenneth M. , Hall William J.
Published: March 2007

The relationship between airway hyperreactivity and a history of the clinical manifestations of asthma was investigated in 54 children between the ages of 8 and 12. Airway reactivity was assessed by measuring the change in pulmonary function following the hyperventilation of subfreezing air. Clinical manifestations of asthma were assessed by a standardized questionnaire regarding lower respiratory symptoms and by medical records review. The subjects were participating in a study of the sequelae of bronchiolitis; 25 had seen a physician for mild bronchiolitis during the first 2 years of life, and the remainder had not. Airway hyperreactivity was demonstrated in 8 of the 54 children and correlated with use of medication for asthma in the 2 years before pulmonary testing and positive parental response to the question, “Does your child wheeze apart from colds?” Airway hyperreactivity did not correlate with a history of other respiratory symptoms or with a history of physician‐diagnosed wheezing or asthma. No questionnaire or chart review item identified over 50% of the children with reactive airways, and most subjects identified by each of the items did not demonstrate hyperreactive airways. These data suggest that airway reactivity is only weakly associated with a history of the clinical manifestations of asthma in childhood, in part because children with clinically inactive asthma do not consistently demonstrate airway hyperreactivity and in part because many children with hyperreactive airways have never had respiratory symptoms.
Determinants of the first inspiratory volume and functional residual capacity at birth
Authors: Vyas H. , Field D. , Milner A. D. , Hopkin I. E.
Published: March 2007

We have investigated the pattern of pressure and volume changes that occur in vaginally delivered, full‐term infants during the onset of spontaneous respiration. Within a few seconds of delivery of the head, simultaneous measurements were made of stomach and esophageal pressure changes together with volume changes determined at the mouth. Values obtained for volume were very similar, but pressure changes were of a greater magnitude than previously reported. A significant correlation has been shown between first inspiratory volume and functional residual capacity (FRC) at the end of the first breath (p < 0.004). No significant relationship was found between first inspiratory pressure and FRC. However, using a calculated index of inspiratory pressure and time (“inspiratory effort”), a significant relationship of this to FRC was observed (p < 0.02).
Diaphragmatic pressures in piglets: Transvenous versus direct phrenic nerve stimulation
Authors: Watchko J. F. , Mayock D. E. , Standaert T. A. , Woodrum D. E.
Published: March 2007

We examined transdiaphragmatic pressure (Pdi) generation during both direct (DPNS) and transvenous (TVPNS) modes of phrenic nerve stimulation in anesthetized piglets of varying postnatal age. Pdi measurements during TVPNS were not statistically different from those obtained during DPNS (p > 0.10). Furthermore, a good correlation (r = 0.98, p < 0.001) was obtained when the mean Pdi measurements obtained by both methods were compared. We conclude that TVPNS can be used in lieu of DPNS to generate Pdi. Furthermore, our data suggest that this technique can be used to study the effects of various experimental manipulations on diaphragmatic force output within a developmental context.