bluuebunny/crossref_metadata_2025 huggingface dataset:
Intracranial aneurysm stenting: Follow‐up with MR angiography
Authors: Lövblad Karl‐Olof , Yilmaz Hasan , Chouiter Amine , Ruiz Diego San Millan , Abdo German , Bijlenga Philippe , Tribolet Nicolas de , Ruefenacht Daniel A
Published: June 2006

Intracranial stenting is increasingly being used to treat intracranial aneurysms and stenoses. We wanted to assess the utility of magnetic resonance angiography (MRA) in the follow‐up of patients treated with various types of intracranial stents and to assess the utility of performing gadolinium‐enhanced MRA. A total of 19 patients having undergone intracranial stenting for aneurysms were imaged by MRI at 1.5T. A total of 20 stents were placed in 19 patients. In addition to conventional T2‐ and diffusion‐weighted MRI, 3D time‐of‐flight MRA was performed before and after contrast administration. In the case of metallic INX stents (N = 7), there was a signal drop at the level of the vessel. which did not allow to evaluating the parent vessel, whereas this was visible in Nitinol stents (N = 8). Additionally a stent with a wire had a small artifact (N = 3). Contrast administration also improved vessel lumen visualization. In the case of Nitinol stents, MRA can be used to reliably demonstrate the vessel lumen after intracranial stenting. The use of postcontrast 3D time‐of‐flight imaging helps improve the intraluminal definition. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Proton MR spectroscopy of the femoral head—Evaluation of patients at risk for avascular necrosis
Authors: Hou Chun‐han , Shih Tiffany Ting‐Fang , Liu Chieh‐Yu , Li Ying‐Ding , Enright Tony
Published: June 2006

Purpose

To detect alteration of the fatty component by measuring the in vivo lipid and water content of normal‐looking femoral heads of patients with and without risk for avascular necrosis (AVN) by using proton MR spectroscopy (MRS).

Materials and Methods

Marrow composition was measured by proton MRS (TR/TE = 5000/20 msec) in a sample volume placed in the epiphysis of the intact femoral heads of patients with unilateral osteonecrosis of the hip (group 1, N = 61, then excluding the post‐traumatic or steroid user, final N = 45) and age‐matched controls (group 2, N = 49). Three response variables were derived from MRS: the lipid linewidth (LW), water LW, and lipid/water ratio.

Results

Of the three variables, the lipid and water LWs differed significantly between groups (P < 0.001 and P = 0.05, respectively; t‐test). The lipid/water ratio had borderline significance (P = 0.06). The three variables differed significantly between groups when multivariate regression (P < 0.0001) was analyzed; and age and sex had no significant effect on the three dependent variables.

Conclusion

Proton MRS can depict alteration in the lipid and water composition of normal‐looking femoral heads with and without AVN on the contralateral hip. Proton MRS may be a potential tool for investigating of the femoral head component in vivo and predicting the risk for development of AVN. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Analysis Of A 105‐year time series of precipitation observed at Uccle, Belgium
Authors: De Jongh Inge L. M. , Verhoest Niko E. C. , De Troch FranÇOis P.
Published: June 2006

The yearly, monthly and seasonal total precipitation of a 105‐year precipitation time series of Uccle, Belgium, were analyzed. Statistically significant trends were found for the yearly total precipitation, for precipitation observed in the winter (DJF) and for the monthly total precipitation of March, using the Mann–Kendall trend test. The few statistically significant trends that were found are shown to be of no statistical significance when the length of the series is changed. Using the adaptive Kolmogorov–Zurbenko (KZA) filter, the droughts around 1920 and during the mid‐1970s and drier‐than‐normal conditions at the beginning of the twentieth century could be detected. Wavelet analysis of the monthly precipitation revealed an expected statistically significant yearly cycle in the data, together with multi‐annual components of 3 and 7 years, which were absent during the period 1935–1945. Copyright © 2006 Royal Meteorological Society
Evaluation of snow/ice albedo parameterizations and their impacts on sea ice simulations
Authors: Liu Jiping , Zhang Zhanhai , Inoue Jun , Horton Radley M.
Published: June 2006

Climate models use a variety of snow/ice albedo parameterizations for the ice covered ocean. In this study, we applied in situ measurements (surface temperature, snow depth and ice thickness) obtained from the Surface Heat Budget of the Arctic Ocean (SHEBA) as input values to four different snow/ice albedo parameterizations (representing the spectrum of parameterizations used in stand‐alone sea ice models, numerical weather prediction and regional climate models of the Arctic Basin, and coupled global climate models), and evaluated the parameterized albedos against the SHEBA observed albedo. Results show that these parameterizations give very different representations of surface albedo. The impacts of systematic biases in the input values on the parameterized albedos were also assessed. To further understand how sea ice processes are influenced by differences in the albedo parameterizations, we examined baseline sea ice characteristics and responses of sea ice to an external perturbation for the simulations of the albedo parameterizations using a stand‐alone basin‐scale dynamic/thermodynamic sea ice model. Results show that an albedo treatment of sufficient complexity can produce more realistic basin‐scale ice distributions, and likely more realistic ice responses as climate warms. Copyright © 2006 Royal Meteorological Society
An efficient multiwavelength light source based on ASE slicing
Authors: Harun S W , Rahman F A , Dimyati K , Ahmad H
Published: June 2006

A multiwavelength light source based on a flat-gain
erbium-doped fiber amplifier (EDFA) and loop mirror is
experimentally demonstrated for single-pass and double-pass
scheme. IsoGainTM erbium-doped fiber is used as a gain
medium for the EDFA, which has a flat-gain of 13.5 dB for the
input power of 0 dBm with gain flatness of less than 1 dB at
wavelength region from 1530 nm to 1570 nm. The loop mirror is
constructed using a 3 dB coupler and polarization maintaining
fiber (PMF). The source generates up to 25 channels within 10 nm
bandwidth of 1550 nm region with a channel spacing of 0.4 nm. The
channel spacing can be varied by controlling the length of the
PMF. The output power of double-pass scheme is obtained at about
-41 dBm, which is more than 15 dB higher compared with
single-pass scheme. However, the signal to noise ratio is only
about 4 dB for the double-pass scheme compared with more than
60 dB for the single-pass scheme.
Self-Q-switched Ytterbium-doped all-fiber laser
Authors: Kir'yanov A V , Barmenkov Yu O
Published: June 2006

We report an experimental realization and study of a
self-Q-switched diode-pumped all-fiber Ytterbium laser. Possible
mechanisms leading to establishing of self-Q-switching in the
laser are discussed.
Ytterbium fiber laser emitting at 1160 nm
Authors: Kurkov A S , Paramonov V M , Medvedkov O I
Published: June 2006

We have realized ytterbium fiber laser emitting at
1160 nm. To avoid a competition with a spontaneous lasing at
shorter wavelengths we pumped laser into the core at wavelength of
1070 nm. Cladding pumped Yb-laser was used as a pump source. Also,
the active fiber was heated up to 70°C to increase the
absorption of the pump power and suppress the spontaneous
emission. The lasing efficiency slope of 45% was measured. A
maximum output power of 3.2 W was achieved.
Stimulated femtosecond photon echo in a dye-doped polymer
film at room temperature
Authors: Lobkov V S , Leontiev A V , Salikhov K M , Samartsev V V , Safiullin G M , Zuikov V A
Published: June 2006

It is reported about the first observation (in a
solid-state sample) and detailed investigation of the stimulated
femtosecond photon echo (SFPE) signals at room temperature in a
polyvinylbutural film doped with molecules of phthalocyanine of HW
1009 type at the wavelength of 788 nm. A dependence of relative
intensity of these echo-signals on time intervals between the
second and the third exciting pulses was studied and the SFPE
spectrum was investigated with respect to the spectra of both
exciting pulses and signals of self-diffraction. It was found that
the linear electron-phonon coupling is weak and the influence of
the phonon-side band of the absorption line on the SFPE signals is
less significantly than on the signals of primary photon echo.
Experimental study of sealed off operation of a high repetition rate
TEA CO2 laser
Authors: Torkamany M J , Kavian M , Zand M
Published: June 2006

Design and construction of a high repetition rate low
average power TEA CO2 laser with ultra violet pre ionization is
presented. Replacing thyratron with a high voltage semiconductor
switch and magnetic pulse compressor considering the highest peak
power achievable is investigated. When using semiconductors as
main switch of laser excitation circuit the output energy and
laser power is lower about 5–10% relative to thyratron
excitation circuit but the sealed off operation of laser is more
uniform.
Cover Picture: Macromol. Chem. Phys. 12/2006
Authors: Mori Hideharu , Ookuma Hiroshi , Nakano Shuji , Endo Takeshi
Published: June 2006

Cover: The graphic shows the use of the xanthate‐type chain transfer agent for controlled radical polymerization of N‐vinylcarbazole. Good control of the polymerization was confirmed by the narrow polydispersity of the products, feasibility to control molecular weight based on the monomer to chain transfer agent ratio (left figure), linear increase in molecular weight with the conversion (middle figure), and ability to extend the chains by the second addition of the monomer (right figure). Further details can be found in the Full Paper by H. Mori,* H. Ookuma, S. Nakano, and T. Endo* on page 1005.
Polymers for tissue engineering, medical devices, and regenerative medicine. Concise general review of recent studies
Authors: Jagur‐Grodzinski Joseph
Published: June 2006

Recently investigated applications of polymeric materials for tissue engineering, regenerative medicine, implants, stents, and medical devices are described in the present review. Papers published during the last 2 years about polymeric materials used for preparation of various polymeric scaffolds, methods of fabrication of such scaffolds and their effectiveness in providing support for cell growth and development into various tissues and enhancing or mimicking an extracellular network (ECM's) have been cited. Papers describing the use of such polymeric materials for tissue engineering of cartilage and bones were cited. The exciting developments in the field of regenerative medicine, based on application of the self‐assembled biocompatible polymeric scaffolds for regeneration of tissues and organs are described in some detail. The use of the biocompatible and biodegradable collapsible polymeric stents, as well as the use of biocompatible, but not necessarily biodegradable polymeric materials for protective coatings of metallic stents and reservoirs of drugs, preventing restenosis and other post‐operative complications that may occur after insertion of a stent, have been reviewed. Clinical results pointing out the advantages of such treatments, as well as results indicating their limitations, have been cited. New formulas, for coating implants, stents, and other medical devices, have been discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis, characterization and liquid crystal‐aligning properties of new poly{3‐[4‐(n‐alkyloxy)phenyloxy]pyromellitimide}s
Authors: Lee Jin Kook , Lee Seong Jun , Jung Jin Chul , Zin Wang‐Cheol , Chang Taihyun , Ree Moonhor
Published: June 2006

Four new polypyromellitimides (MCm‐PPIs and MCm‐OPIs, m = 6, 8) that are singly substituted with a flexible n‐alkyloxy side branch at the pyromellitimide ring were prepared by the two‐step polycondensation of 3‐[4‐(n‐alkyloxy)phenyloxy]pyromellitic dianhydrides (MCm‐PMDAs, m = 6, 8) with p‐phenylenediamine (PDA) and 4,4′‐oxydianiline (ODA), respectively. The dianhydride monomers were synthesized from durene via several reaction steps. Inherent viscosities of the precursor poly(amic acid)s ranged from 0.57 to 1.58 dl/g. After chemical structures of the polyimides had been characterized, their thermal properties, crystalline structures, and liquid crystal (LC) aligning abilities on their rubbed thin films were determined and discussed in comparison to the polypyromellitimides that are doubly substituted at the pyromellitimide ring with the same side branches. For all polymers thermogravimetric analysis (TGA) programs showed a typical two‐step degradation behavior with onset temperatures in the 430–455°C range. In X‐ray scattering studies all the samples were found to be amorphous, but the presence of a loosely developed layer structure could be confirmed, in which two main chains gather together to form a double‐strand backbone layer and n‐alkyl branches fill the space between the layers. On the rubbed surfaces of the polyimide thin films LCs uniformly aligned parallel to the rubbing direction with the pre‐tilt angles 5–7° in MCm‐OPIs and 18–32° in MCm‐PPIs. Copyright © 2006 John Wiley & Sons, Ltd.
Statin therapy induces ultrastructural damage in skeletal muscle in patients without myalgia
Authors: Draeger A , Monastyrskaya K , Mohaupt M , Hoppeler H , Savolainen H , Allemann C , Babiychuk EB
Published: June 2006

Muscle pain and weakness are frequent complaints in patients receiving 3‐hydroxymethylglutaryl coenzymeA (HMG CoA) reductase inhibitors (statins). Many patients with myalgia have creatine kinase levels that are either normal or only marginally elevated, and no obvious structural defects have been reported in patients with myalgia only. To investigate further the mechanism that mediates statin‐induced skeletal muscle damage, skeletal muscle biopsies from statin‐treated and non‐statin‐treated patients were examined using both electron microscopy and biochemical approaches. The present paper reports clear evidence of skeletal muscle damage in statin‐treated patients, despite their being asymptomatic. Though the degree of overall damage is slight, it has a characteristic pattern that includes breakdown of the T‐tubular system and subsarcolemmal rupture. These characteristic structural abnormalities observed in the statin‐treated patients were reproduced by extraction of cholesterol from skeletal muscle fibres in vitro. These findings support the hypothesis that statin‐induced cholesterol lowering per se contributes to myocyte damage and suggest further that it is the specific lipid/protein organization of the skeletal muscle cell itself that renders it particularly vulnerable. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Calculation of proton affinity using the CR‐CCSD[T]/ECP method
Authors: Morgon Nelson H.
Published: June 2006

High‐level calculations of proton and electron affinities (PA and EA) of CH2X− and CH2CHCHX− (with X = F, Cl, Br, and I) systems were obtained. The methodology employed in the PA and EA calculations is based on CR‐CCSD[T]/B1//MP2/B0 and CCSD(T)/B1//MP2/B0 levels, respectively. B0 is a (small) valence basis set developed by Stevens and colleagues (SBKJC), and B1 is a larger basis set, with extra diffuse and polarization functions (B0 + s, p, d, and f functions). This scheme has been tested on systems containing H, C, and X atoms, and is shown to give good results. The differences between calculated results of PA and EA and the experimental values are in the range of 0.2–4.5 kJ · mol−1 and 0.01 to 0.10 eV, respectively. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Adapted relativistic prolapse‐free Gaussian basis sets for closed shell atoms up to nobelium and to be used with the uniform sphere nucleus model
Authors: De Macedo Luiz Guilherme M. , Haiduke Roberto L. A. , Comar Moacyr , Da Silva Albérico B. F.
Published: June 2006

Prolapse‐free relativistic Gaussian basis sets are presented for all the closed‐shell elements up to nobelium, using the spherical nuclear model. These relativistic Gaussian basis sets were generated using the polynomial version of the generator coordinate Dirac–Fock (p‐CGDF) method with the goal of obtaining an energy difference with respect to numerical results in the millihartree order of magnitude, resulting in a good balance between cost and accuracy. The discretization parameters for generating the Gaussian exponents are also presented. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
A spatial scan statistic for ordinal data
Authors: Jung Inkyung , Kulldorff Martin , Klassen Ann C.
Published: June 2006

Spatial scan statistics are widely used for count data to detect geographical disease clusters of high or low incidence, mortality or prevalence and to evaluate their statistical significance. Some data are ordinal or continuous in nature, however, so that it is necessary to dichotomize the data to use a traditional scan statistic for count data. There is then a loss of information and the choice of cut‐off point is often arbitrary. In this paper, we propose a spatial scan statistic for ordinal data, which allows us to analyse such data incorporating the ordinal structure without making any further assumptions. The test statistic is based on a likelihood ratio test and evaluated using Monte Carlo hypothesis testing. The proposed method is illustrated using prostate cancer grade and stage data from the Maryland Cancer Registry. The statistical power, sensitivity and positive predicted value of the test are examined through a simulation study. Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of the short form‐36 (SF‐36): the beta‐binomial distribution approach
Authors: Arostegui Inmaculada , Núñez‐Antón Vicente , Quintana José M.
Published: June 2006

Health‐related quality of life (HRQoL) is an important indicator of health status and the Short Form‐36 (SF‐36) is a generic instrument to measure it. Multiple linear regression (MLR) is often used to study the relationship of HRQoL with patients' characteristics, though HRQoL outcomes tend to be not normally distributed, skewed and bounded (e.g. between 0 and 100). A sample of 193 patients with eating disorders has been analysed to assess the performance of the MLR under non‐normality conditions. Normal distribution was rejected for seven out of the eight domains. A beta‐binomial distribution is suggested to fit the SF‐36 scores. The beta‐binomial distribution is not rejected for five out of the eight domains. Thus, a beta‐binomial regression (BBR) is suggested to analyse the SF‐36 scores. Results using MLR and BBR have been compared for real and simulated data. Performance of the BBR is shown to be better than MLR in the HRQoL domains with few ordered categories and very similar to MLR in the more continuous domains. Moreover, the interpretation of the estimates obtained with BBR is clinically more meaningful. A common technique of statistical analysis is preferable for all the HRQoL dimensions. Therefore, the BBR approach is recommended not only to detect significant predictors of HRQoL when SF‐36 is used, but also to analyse and interpret the effect of several explanatory variables on HRQoL. Further work is required to test the better performance of BBR against standard methods for other HRQoL outcomes, populations or interventions. Copyright © 2006 John Wiley & Sons, Ltd.
A systematic review of the accuracy of first‐trimester ultrasound examination for detecting major congenital heart disease
Authors: Rasiah S. V. , Publicover M. , Ewer A. K. , Khan K. S. , Kilby M. D. , Zamora J.
Published: June 2006

Objective

To evaluate the accuracy of first‐trimester ultrasound examination in detecting major congenital heart disease (CHD) using a systematic review of the literature.

Methods

General bibliographic and specialist computerized databases along with manual searching of reference lists of primary and review articles were used to search for relevant citations. Studies were included if a first‐trimester ultrasound scan was carried out to detect CHD that was subsequently verified by a reference standard. Data were extracted on study characteristics and quality, and 2 × 2 tables were constructed to calculate sensitivity and specificity.

Results

Ten studies (involving 1243 patients) were suitable for inclusion. Of these, four used transabdominal ultrasonography, four used transvaginal and two used a combination. Pooled sensitivity and specificity were 85% (95% CI, 78–90%) and 99% (95% CI, 98–100%), respectively.

Conclusion

Ultrasound examination of the fetus in the first trimester is feasible for accurately detecting major CHD. It may be offered to women at high risk of having children with CHD. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis and outcome for fetuses with congenital absence of the pulmonary valve
Authors: Galindo A. , Gutiérrez‐Larraya F. , Martínez J. M. , del Rio M. , Grañeras A. , Velasco J. M. , Puerto B. , Gratacos E.
Published: June 2006

Objectives

To analyze fetal echocardiographic findings of absent pulmonary valve syndrome (APVS), its association with chromosomal and extracardiac anomalies including nuchal translucency (NT) and the outcome after diagnosis.

Methods

Data of 14 fetuses with confirmed APVS retrospectively collected in two tertiary referral centers between 1998 and 2004 were analyzed. The variables examined were: reason for referral, gestational age at diagnosis and associated abnormalities, including first trimester NT thickness. Cardiac evaluation included measurement of cardiothoracic ratio, diameter of pulmonary arteries and Doppler flow in the pulmonary trunk. Information was retrieved from clinical files, recorded videotapes and stored images. Karyotyping including examination for the 22q11 deletion was performed in all cases.

Results

Mean gestational age at diagnosis was 28 weeks, with 5/14 (36%) diagnosed before 22 weeks. In 13/14 (93%) there was an associated ventricular septal defect (subaortic in 12 fetuses and inlet‐type in one) and all 13 had tetralogy of Fallot. Enlargement of the central pulmonary arteries and cardiomegaly were present in all cases diagnosed after 22 weeks. Of the five fetuses in which APVS was detected before 22 weeks, four (80%) had a normal pulmonary trunk diameter, two (40%) had normal pulmonary branches and three (60%) had normal cardiac size. The arterial duct was absent in 11/14 (79%). A correlation between presence of the arterial duct and the size of the central pulmonary arteries or cardiomegaly could not be established. Increased NT was observed in 4/10 cases (40%) for which this information was available. 22q11 microdeletion was diagnosed in three fetuses (21%). There were five terminations of pregnancy, one intrauterine death, five neonatal deaths and one infant death. Of the six neonates with respiratory distress, only one (17%) survived and of the eight babies in whom there was an intention to treat, two survived (25%).

Conclusions

APVS can be accurately diagnosed by fetal echocardiography but screening ultrasound in the mid‐second trimester is likely to have a low detection rate, probably due to the incomplete expression of the disease at this point. Many fetuses with APVS have an increased NT in the first trimester and this may help an earlier recognition of the defect. The most common associated karyotype anomaly is 22q11 microdeletion. Enlargement of the central pulmonary arteries is mainly related to the gestational age at diagnosis. Our results confirm that the outlook for these patients is extremely poor. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound‐guided injection and occlusion of the trachea in fetal sheep
Authors: David A. L. , Weisz B. , Gregory L. , Themis M. , Cook T. , Roubliova X. , Deprest J. , Coutelle C. , Rodeck C. H. , Peebles D. M.
Published: June 2006

Objectives

To access the fetal sheep trachea by ultrasound‐guided transthoracic injection in order to deliver gene therapy vectors or occlude the trachea with a detachable balloon.

Methods

Fetal sheep were operated on at a mean gestational age of 102 (range, 81–116) days (term = 145 days). Under ultrasound guidance, either a 20‐G spinal (for vector delivery) or a 16‐G Kellett (for placement of an occlusive balloon) needle was inserted via the fetal thorax into the fetal trachea.

Results

Using the 20‐G spinal needle the trachea was accessed successfully in 33/36 fetuses, with 97% survival. Failure to inject was related to fetal position and gestational age. Blood vessel damage causing significant morbidity occurred in two fetuses (6%). Tracheal occlusion was achieved by puncturing the trachea with the 16‐G needle and advancing an endoluminal balloon in three out of five attempts in a mean time of 17 (range, 16–19) min, with 100% survival. In one case, the balloon became sited within the accessory lobe bronchus and was not inflated. At postmortem examination 21 days later, all balloons remained inflated and occluded the trachea, and the lung‐to‐body weight ratio and airways morphometric indices were consistent with relative pulmonary hyperplasia in the obstructed lungs.

Conclusions

Ultrasound‐guided transthoracic tracheal puncture is a reliable technique in fetal sheep, with low morbidity and mortality. Using this technique, a detachable endotracheal balloon can be placed to provoke pulmonary growth. Advances in needle design and balloon size may improve the success rate. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Novel application of 4D sonography with B‐flow imaging and spatio‐temporal image correlation (STIC) in the assessment of the anatomy of pulmonary arteries in fetuses with pulmonary atresia and ventricular septal defect
Authors: Volpe P. , Campobasso G. , Stanziano A. , De Robertis V. , Di Paolo S. , Caruso G. , Volpe N. , Gentile M.
Published: June 2006

Objectives

To assess the reliability of two‐dimensional gray‐scale (2D) and color Doppler echocardiography in the study of the size and anatomy of the central pulmonary arteries and of the sources of pulmonary blood flow in a case series of fetuses with pulmonary atresia and ventricular septal defect (PA‐VSD), and to evaluate whether the use of 4D ultrasound with B‐flow imaging and spatio‐temporal image correlation (STIC) can improve prenatal diagnostic accuracy.

Methods

The study population comprised a group of seven PA‐VSD fetuses that had been examined by 2D and color Doppler echocardiography exclusively, and a group of five additional cases identified initially by conventional echocardiography and examined further by 4D ultrasound, for all of which a thorough postnatal or autopsy study of the size and anatomy of the pulmonary arteries and blood supply was available.

Results

2D and color Doppler echocardiography failed to assess the anatomy of the central pulmonary arteries and the source of the pulmonary blood supply in 33% and 25% of the 12 cases, respectively. 4D ultrasound with B‐flow imaging and STIC assessed successfully the anatomy of the pulmonary arteries and the source of pulmonary blood supply in all five fetuses examined.

Conclusions

The prognosis of PA‐VSD is influenced by the anatomy of the pulmonary arteries and the sources of the pulmonary blood supply, and by coexisting extracardiac and genetic anomalies. Our findings, although limited to a small sample size, suggest that 4D echocardiography with B‐flow imaging and STIC, unlike 2D ultrasound, can provide thorough visualization of very small vessels and of the arterial blood supply to the lungs of fetuses with PA‐VSD. 4D ultrasound may be used in the future to improve and help to detail the diagnosis of other fetal cardiac defects. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Simple approach to prenatal diagnosis of transposition of the great arteries
Authors: Viñals F. , Ascenzo R. , Poblete P. , Comas C. , Vargas G. , Giuliano A.
Published: June 2006

Objective

To analyze the most relevant anomalies, seen in a sequential segmental transverse views approach to imaging the fetal heart, that provide clues to the diagnosis of complete transposition of the great arteries (TGA).

Methods

We reviewed retrospectively all the cases of isolated TGA diagnosed in our center or submitted for a second opinion through the spatio‐temporal image correlation (STIC) telemedicine (TELE‐STIC) program. Only transverse cardiac sweeps were obtained. Digital video clips and STIC volumes were reviewed. The abnormal features on four‐chamber, five‐chamber, three‐vessel (3V) and three vessels and trachea (3VT) views were analyzed.

Results

The study population consisted of eight fetuses with TGA with normal extracardiac anatomy. The gestational age ranged from 13 to 32 (mean, 23) weeks. The maternal age ranged from 25 to 42 (mean, 32) years. A normal four‐chamber view was seen in seven cases. Only one case demonstrated a significant ventricular septal defect. At the level of the five‐chamber view a straight course arterial vessel arose from the left ventricle with lateral branches in all fetuses. In the 3V view, the ascending aorta was seen reaching more anteriorly than was the pulmonary artery in six cases. At the level of the 3VT view, two vessels (transverse aortic arch and superior vena cava) rather than three were seen in all cases.

Conclusion

Our proposed sequential segmental approach to imaging the fetal heart apparently allows, in five‐chamber and 3VT views, clear and confident signs to be detected that aid diagnosis of TGA. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Development of hypoplastic left heart syndrome after diagnosis of aortic stenosis in the first trimester by early echocardiography
Authors: Axt‐Fliedner R. , Kreiselmaier P. , Schwarze A. , Krapp M. , Gembruch U.
Published: June 2006

We describe a case of aortic stenosis in the first trimester that progressed to hypoplastic left heart syndrome. At 11 + 3 weeks' gestation the four‐chamber view was normal but evidence of increased aortic blood velocity prompted the diagnosis of aortic outflow obstruction. At 16 + 6 weeks' gestation the left ventricle was hyperechogenic, globular and dysfunctional, suggesting the development of hypoplastic left heart syndrome. The aortic valve was small and there was no flow across the mitral or aortic valves. From 17 + 3 weeks increased reversed flow in the pulmonary veins suggested restriction of the foramen ovale. Follow‐up echocardiographic examinations were performed every 2–3 weeks until delivery at term. Postnatal intervention included a Norwood I operation performed on the 5th postnatal day.

We have shown the feasibility and utility of early fetal echocardiography and that a left heart obstruction diagnosed in the first trimester can progress to left heart hypoplasia during the early second trimester. This information is important for planning prenatal and perinatal management. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Reference ranges for Doppler parameters of the fetal aortic isthmus during the second half of pregnancy
Authors: del Río M. , Martínez J. M. , Figueras F. , López M. , Palacio M. , Gómez O. , Coll O. , Puerto B.
Published: June 2006

Objective

To establish reference ranges for blood flow velocity waveforms (FVW) of the fetal aortic isthmus (AoI) during the second and third trimesters of pregnancy.

Methods

This was a prospective cross‐sectional observational study involving 458 uncomplicated singleton pregnancies between 19 and 37 weeks of gestation. Fetal AoI Doppler parameters were assessed in either the longitudinal aortic arch view or the three vessels and trachea view. Regression analysis was used to determine gestational‐age‐specific reference ranges and to construct nomograms for the following Doppler parameters: pulsatility index (PI), resistance index (RI) and peak systolic (PSV), end‐diastolic (EDV) and time‐averaged maximum (TAMXV) velocities. Intra‐ and interobserver reproducibility were evaluated by calculating intraclass correlation coefficients (ICCs) and limits of agreement.

Results

Reliable FVW in the AoI were obtained in all cases. Acceptable intra‐ and interobserver reproducibility was obtained. With advancing gestation, there was a significant increase in PSV, TAMXV and PI, whereas RI and EDV remained constant during the second half of pregnancy. No cases of absent or reversed flow during diastole were detected.

Conclusion

Normal data of the fetal AoI blood FVW throughout the second and third trimesters of pregnancy are provided. The reported Doppler profiles may be of clinical use in the assessment of hemodynamically compromised growth‐restricted fetuses. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Wolfram syndrome‐associated mutations lead to instability and proteasomal degradation of wolframin
Authors: Hofmann Sabine , Bauer Matthias F.
Published: June 2006

Wolfram syndrome is caused by mutations in WFS1 encoding wolframin, a polytopic membrane protein of the endoplasmic reticulum. Here, we investigated the molecular pathomechanisms of four missense and two truncating mutations in WFS1. Expression in COS‐7 cells as well as direct analysis of patient cells revealed that WFS1 mutations lead to drastically reduced steady‐state levels of wolframin. All mutations resulted in highly unstable proteins which were delivered to proteasomal degradation. No wolframin aggregates were found in patient cells suggesting that Wolfram syndrome is not a disease of protein aggregation. Rather, WFS1 mutations cause loss‐of‐function by cellular depletion of wolframin.
Oxygen binding and NO scavenging properties of truncated hemoglobin, HbN, of Mycobacterium smegmatis
Authors: Lama Amrita , Pawaria Sudesh , Dikshit Kanak L.
Published: June 2006

Unraveling of microbial genome data has indicated that two distantly related truncated hemoglobins (trHbs), HbN and HbO, might occur in many species of slow‐growing pathogenic mycobacteria. Involvement of HbN in bacterial defense against NO toxicity and nitrosative stress has been proposed. A gene, encoding a putative HbN homolog with conserved features of typical trHbs, has been identified within the genome sequence of fast‐growing mycobacterium, Mycobacterium smegmatis. Sequence analysis of M. smegmatis HbN indicated that it is relatively smaller in size and lacks N‐terminal pre‐A region, carrying 12‐residue polar sequence motif that is present in HbN of M. tuberculosis. HbN encoding gene of M. smegmatis was expressed in E. coli as a 12.8 kD homodimeric heme protein that binds oxygen reversibly with high affinity (P
50
∼ 0.081 mm Hg) and autooxidizes faster than M. tuberculosis HbN. The circular dichroism spectra indicate that HbN of M. smegmatis and M. tuberculosis are structurally similar. Interestingly, an hmp mutant of E. coli, unable to metabolize nitric oxide, exhibited very low NO uptake activity in the presence of M. smegmatis HbN as compared to HbN of M. tuberculosis. On the basis of cellular heme content, specific nitric oxide dioxygenase (NOD) activity of M. smegmatis HbN was nearly one‐third of that from M. tuberculosis. Additionally, the hmp mutant of E. coli, carrying M. smegmatis HbN, exhibited nearly 10‐fold lower cell survival under nitrosative stress and nitrite derived reactive nitrogen species as compared to the isogenic strain harboring HbN of M. tuberculosis. Taken together, these results suggest that NO metabolizing activity and protection provided by M. smegmatis HbN against toxicity of NO and reactive nitrogen is significantly lower than HbN of M. tuberculosis. The lower efficiency of M. smegmatis HbN for NO detoxification as compared to M. tuberculosis HbN might be related to different level of NO exposure and nitrosative stress faced by these mycobacteria during their cellular metabolism.
Explaining the Sources of de facto Federalism in Reform China: Intergovernmental Decentralization, Globalization, and Central–Local Relations
Authors: ZHENG YONGNIAN
Published: June 2006

China does not have a federalist system of government. Nevertheless, with deepening reform and openness, China's political system in terms of central–local relations is functioning more and more like federalism. Federalism as a functioning system in China has been understudied. This paper defines the political system existing in China as de facto federalism, and attempts to explore the sources and dynamics of this de facto federalism. China's de facto federalism was mainly driven by two related factors, i.e. decentralization and globalization. This paper argues that while economic decentralization in the 1980s led to the formation of de facto federalism, globalization since the 1990s has accelerated this process and generated increasingly high pressure on the Chinese leadership to institutionalize existing de facto federalism.
The Non-Linear Process of Institutional Change: The Bank of Japan Reform and Its Aftermath
Authors: LUKAUSKAS ARVID J. , SHIMABUKURO YUMIKO
Published: June 2006

In 1997, the Japanese Diet revised the Bank of Japan law thereby granting the central bank greater independence in monetary policy making. The revision was an attempt by Japan's political class to weaken the authority of the powerful Ministry of Finance over the central bank and augment its own influence. The Bank of Japan, however, gained more autonomy than politicians ever intended, leading to frequent confrontations between the government and the central bank over monetary policy. This paper explores the new strategic relationship that emerged between the Bank of Japan and government and the nature of monetary policy implemented in the post-reform period. We demonstrate that several factors contributed to the Bank's unexpected ability to enhance its independence: the astute leadership of the first post-reform governor Hayami Masaru; the Bank's ability to turn politicization of monetary policy to its advantage; and its pursuit of a ‘power through knowledge’ strategy achieved by augmenting its own research capacity. On a theoretical level, our findings show that the passage of a new legal framework only marks the completion of one stage of institutional change and the start of the next; post-enactment politics have as much importance as pre-enactment politics in shaping outcomes. In the post-enactment phase, various factors, including the state of the economy and informal institutions or processes, matter greatly and may shift the direction of institutional change away from the intended path.
Thailand's Missed Opportunity for Democratic Consolidation
Authors: FREEDMAN AMY
Published: June 2006

The year 1997 was critical for Thailand. A severe economic crisis hit in July calling into question years of economic growth and increasing prosperity. A few months later Thailand adopted a new Constitution that aimed at reforming the political system, and at making corruption and vote buying less prevalent. While this article shows that the economic turmoil was a prime catalyst for political change, it was not as simple as saying that public outcry over the economic crisis forced conservative parliamentarians into voting to accept the proposed constitution. While public outcry did matter, what is vitally important is that elite political leaders, the heads of the major parties, ministers, and generals, were renegotiating their alliances and ties both with one another, and with various groups in society that were pushing for change. Elite resignation to political pressure and policy shifts among the top leaders is what ultimately allows for the passage of the constitution and for Prime Minister Chavalit's departure. This article takes a closer look at Thai politics and tries to answer the following questions: Did the economic crisis lead to (meaningful) political reform and why or why not? Since the codification of the 1997 constitution has Thai politics become more democratic? It is my analysis that the consolidation of democracy was in reach in 1997 but today has slipped further from Thai citizens' grasp. The explanations, or the independent variables for both the successful reforms of the political system in 1997 and the backsliding away from democratization, are largely the same. When both internal and external pressures prod democracy along, reforms take place. When pressures are pushing in different directions democratic reforms become threatened. Internal pressures include the military, civil society, and the behavior and power of political and economic elites; and external ones are the IMF, national security concerns, and globalization in general. When conditions or variables change, and when elite priorities or preferences shift, as this article will show, we can see the results in Thai politics.
Quantifying Social Capital in Central and South Asia: Are There Democratic, Developmental, and Regionalizing Potentials?
Authors: INOGUCHI TAKASHI , HOTTA ZEN-U LUCIAN
Published: June 2006

This paper aims to apply the methodology used in Inoguchi's former paper (2004c) and build on to the findings concerning social capital in Asia. The previous paper used ten Asian countries from the AsiaBarometer 2003 survey; this time we are using the 14 Central and South Asian countries – Kazakhstan, India, Pakistan, Afghanistan, Sri Lanka, Bangladesh, Maldives, Bhutan, Mongolia, Nepal, Tajikistan, Turkmenistan, Kyrgyzstan, and Uzbekistan – from the AsiaBarometer 2005 survey.
Das Magenkarzinom – Risikofaktoren und internistische Therapie
Authors: Harder  , Opitz
Published: June 2006

Das Magenkarzinom ist nach wie vor die vierthäufigste Tumorentität und die zweithäufigste tumorassoziierte Todesursache weltweit. Die distalen Magenkarzinome sind zwar in ihrer Inzidenz abnehmend, aber durch ihre hohen Mortalitätsraten weiter ein bedeutendes klinisches Problem. Im Gegensatz hierzu sind die Tumoren des gastro-ösophagealen Übergangs die am stärksten zunehmenden Neoplasien der westlichen Welt. Das Magenkarzinom wird meistens erst in fortgeschrittenen Stadien diagnostiziert, zu einem Zeitpunkt bei dem die Behandlungsmöglichkeiten schon sehr eingeschränkt sind. Dies führt insgesamt zu einer nach wie vor sehr schlechten Prognose dieser Tumorerkrankung. Über die letzten 15 Jahre wurden einige Fortschritte im Verständnis der Risikofaktoren und Pathogenese des Magenkarzinoms gemacht. Als wichtigster, exogener Risikofaktor wurde Helicobacter pylori von der WHO als ein Klasse-I-Karzinogen eingestuft. Ebenso konnten in den letzten Jahren verschiedene genetische Veränderungen, die mit einem erhöhten Risiko eines Magenkarzinoms assoziiert sind, definiert werden. Auch im Bereich der Therapie des Magenkarzinoms sind durch neue multimodale Strategien, wenn auch erst langsam, Fortschritte erzielt worden. In Zukunft könnten diese Errungenschaften zum einen zu einer besseren Früherkennung von Risikopatienten, zum anderen, durch den gezielten Einsatz von derzeit multimodalen und in Zukunft vielleicht gezielten Therapieansätzen, zur Verbesserung der Prognose dieser Tumorentität führen.
Barrettkarzinom
Authors: Messmann
Published: June 2006

Die Inzidenz des Barrettösophagus, sowohl des Long-Segment als auch Short-Segment, hat in den letzten Jahren deutlich zugenommen. Ein wesentlicher Grund liegt hier aber in der Zunahme der Endoskopiezahlen. Gleichzeitig nimmt in der westlichen Welt aber auch das Barrettadenokarzinom zu, während die Inzidenz des Plattenepithelkarzinoms abnimmt. Neben einer verbesserten endoskopischen Detektion scheinen hier aber andere Faktoren, insbesondere exogene wie Ernährung, Reflux und Adipositas eine Rolle zu spielen.Aufgrund der jetzigen Datenlage kann man festhalten, dass das Risiko des Barrettadenokarzinoms überschätzt wurde. Dies lag v.a. an einem Publikationsbias. Das Risiko für ein Barrettadenokarzinom wird derzeit mit 0.5%/Jahr angegeben. Sowohl in deutschen als auch in den amerikanischen Leitlinien wird eine Screeningendoskopie generell nicht empfohlen, lediglich bei langjährigem Reflux sollte eine Ösophago-Duodeno-Gastroskopie (ÖGD) vorgenommen werden. Die Diagnose des Barrettösophagus ist eine endoskopisch-histologische, d.h. die Entnahme von 4-Quadrantenbiospien in 1–2 cm Abständen ist derzeitiger Goldstandard. Möglicherweise können Färbemethoden (Methylenblau, Essigsäure) in Kombination mit der Zoomendoskopie die Diagnose erleichtern. Beim gesicherten Barrettösophagus werden regelmässige Überwachungsendoskopien je nach Vorhandensein von intraepithelialen Neoplasien empfohlen.Während beim Barrettösophagus ohne bzw. mit leichtgradigen intraepithelialen Neoplasien nur Überwachungen erforderlich sind, sollte beim Nachweis von schwergradigen intraepithelialen Neoplasien eine Therapie durchgeführt werden. Bei sichtbaren Läsionen hat sich zunehmend die EMR als erfolgversprechend gezeigt, da sie bei gleicher Effektivität eine niedrigere Mortalität und Morbidität aufweist als die Operation. Bei nicht sichtbaren intraepithelialen Neoplasien ist die photodynamische Therapie ein Erfolg versprechendes Verfahren. In Analogie zu den schwergradigen intraepithelialen Neoplasien können mukosale Barrettadenokarzinome ebenso endoskopisch behandelt werden. Beim Nachweis eines submukosalen Karzinoms ist die Operation erforderlich.
Magenfrühkarzinom – Diagnostik und Therapie
Authors: Kolfenbach  , Malfertheiner
Published: June 2006

Das Magenfrühkarzinom ist definiert als ein auf die Mukosa oder Submukosa beschränkter invasiv wachsender Tumor vom intestinalen Typ. Mit der endoskopischen Mukosektomie steht ein neues, viel versprechendes, den Patienten wenig belastendes Resektionsverfahren zur Verfügung. Hierdurch kann ausgewählten Patienten eine Operation erspart werden. Die EMR ist eine viel versprechende minimal invasive Methode für Patienten mit einem Magenfrühkarzinom vom intestinalen Typ.
Thresholds for bed load transport and channel initiation in a chert area in Ashio Mountains, Japan: An empirical approach from hydrogeomorphic observations
Authors: Hattanji Tsuyoshi , Onda Yuichi , Matsukura Yukinori
Published: June 2006

We examined the effect of bed load transport on channel‐head locations where shallow landsliding is infrequent. Area‐slope thresholds for bed load transport estimated from hydrogeomorphic observations were compared with certain area‐slope relations at 24 channel heads in a chert area, the Ashio Mountains, Japan. The hydrogeomorphic observations include (1) spring discharge at 12 sites, (2) rainfall intensity, and (3) peak discharge and bed load transport immediately below two channel heads of differing gradient. We confirmed an increase of spring discharge in proportion to drainage area during a stormflow. We performed regression analyses involving the peak 4‐hour rainfall and the peak discharge per unit area to give the optimal rainfall‐runoff equation. The bed load yield increases abruptly when the peak discharge exceeds a critical discharge. We calculated area‐slope thresholds for bed load transport for 1‐year and 100‐year rainfalls, combining the rainfall‐runoff equation with the critical discharge. More than half of all channel heads are located where peak discharge produced by frequent rainstorms (return intervals of less than 100 years) is sufficient to transport bed load. In mountains where shallow landsliding is infrequent, bed load transport has a strong influence on channel‐head location.
Radiation impedance over a thunderstorm
Authors: Farrell W. M. , Goldberg R. A. , Blakeslee R. J. , Desch M. D. , Mach D. M.
Published: June 2006

In the summer of 2002 the Altus Cumulus Electrification Study obtained radiated Poynting flux measurements in the near vicinity of lightning discharge events. These measurements not only allow a determination of radiated power but also allow a calculation of the radiation impedance above a thunderstorm when the thunderstorm was acting as an antenna. This impedance is significant since it defines the level of displacement currents propagating into the middle atmosphere and, as applications demonstrate, is a critical quantity in understanding the relationship between power and displacement current in the near vicinity of a thunderstorm. We find that the radiation impedance of the thunderstorm is surprisingly low in the VLF and varies inversely with frequency consistent with a capacitive‐like coupling from the thunderstorm to middle atmosphere.