bluuebunny/crossref_metadata_2025 huggingface dataset:
Liver microsomal biotransformation of nitro‐aryl drugs: mechanism for potential oxidative stress induction
Authors: Letelier M. E. , Izquierdo P. , Godoy L. , Lepe A. M. , Faúndez M.
Published: November 2004

Toxic effects of several nitro‐aryl drugs are attributed to the nitro‐reduction that may be suffered in vivo, a reaction that may be catalysed by different reductases. One of these enzymes is NADPH–cytochrome P450 reductase, which belongs to the cytochrome P450 oxidative system mainly localized in the endoplasmic reticulum of the hepatic cell. This system is responsible for the biotransformation of oxidative lipophilic compounds, so that oxidative and reductive metabolic pathways of lipophilic nitro‐aryl drugs can take place simultaneously. Because of the afﬁnity of nitro‐aryl drugs (xenobiotics) for the endoplasmic reticulum, we propose this subcellular organelle as a good biological system for investigating the toxicity induced by the biotransformation of these or another compounds.

In this work we used rat liver microsomes to assess the oxidative stress induced by nitro‐aryl drug biotransformation. Incubation of microsomes of rat liver with nifurtimox and nitrofurantoin in the presence of NADPH induced lipoperoxidation, UDP‐glucuronyltransferase activation and an increase in the basal microsomal oxygen consumption. Nitro‐aryl‐1,4‐dihydropyridines did not elicit these prooxidant effects; furthermore, they inhibited lipoperoxidation and oxygen consumption induced by Fe3+/ascorbate. Nifurtimox and nitrofurantoin modiﬁed the maximum absorption of cytochrome P450 oxidase and inhibited p‐nitroanisole O‐demethylation, an oxidative reaction catalysed by the cytochrome P450 system, signifying that oxidation may proceed in a similar way to that described for nitro‐aryl‐1,4‐dihydropyridines. Thus the balance between lipophilic nitro‐aryl drug oxidation and reduction may be involved in the potential oxidative stress induced by biotransformation. Copyright © 2004 John Wiley & Sons, Ltd.
Statistical correlation between cell adhesion and proliferation on biocompatible metallic materials
Authors: Bigerelle M. , Anselme K.
Published: November 2004

Our ambition for several years is to appreciate and quantify the long‐term adhesion of cells on materials at times where the interface between cells and substrate becomes more complex, more closed to the cell/matrix/substrate interface existing in vivo. With this objective, we quantified the long‐term adhesion and proliferation of human osteoblasts cultured from 24 h to 21 days on pure titanium, titanium alloy, and stainless‐steel substrates presenting six different surface morphologies and two different roughness amplitude. Hence, we did proceed to the statistical correlation of cell adhesion and cell proliferation on 30 different substrates. Additionally, we described surface topography not only by the roughness amplitude but also by the roughness morphology using new specific parameters. By multiple analysis of variance, we demonstrated that nor material composition nor surface roughness amplitude did influence cell proliferation, whereas a very significant influence of the process used to produce the surface was observed meaning that the main influent factor on cell proliferation was the surface morphology. The long‐term adhesion and proliferation capacity of cells were positively correlated on 23 types of substrates on 30, this positive correlation being statistically asserted on 13 types of substrates on 23. This study is the first demonstration of the existence of a statistical correlation between long‐term adhesion and proliferation capacity of human bone cells on substrates with various chemical composition, surface chemistry, and surface topography. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 36–46, 2005
Biaxial flexure testing of calcium phosphate bioceramics for use in tissue engineering
Authors: Meganck Jeffrey A. , Baumann Melissa J. , Case Eldon D. , McCabe Laura R. , Allar Jaclyn N.
Published: November 2004

This study analyzes data from 206 CaP specimens (68 HA, 70 BCP, and 68 β‐TCP) fractured via biaxial flexure testing. Specimens were divided into four groups: (a) Group I, dry; (b) Group II, wet (day 0, immersion time ∼ 5–10 s); (c) Group III, after immersion in media for 21 days (day 21); and (d) Group IV, after culturing osteoblasts (OBs) on the surface for 21 days (day 21 with cells). X‐ray diffraction verified the presence of minor second phases in HA and β‐TCP while BCP was a biphasic mixture of HA and β‐TCP with minor phases present. The statistical significance (p < 0.05) of differences in the measured biaxial flexure fracture strength, S, between groups was assessed via one‐way ANOVA with Tukey's test. Also, a two‐parameter Weibull analysis assessed the mechanical reliability of each group. Osteoblasts increase the biaxial flexure fracture strength in a statistically significant way compared to both the HA discs in Groups II and III. Scanning electron microscope examination revealed grain boundary grooving on the sintered surfaces and with thermal expansion anisotropy, likely leads to the observed rapid strength decline upon exposure to media found in Groups II, III and IV. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 115–126, 2005
Remythologizing culture: Narrativity, justification, and the politics of personalization
Authors: Quackenbush Steven W.
Published: November 2004

The thesis that the self is a story unfolding inprescriptivespace is typically embraced by social constructionists as a radical alternative to naturalistic accounts of human development. Yet, the Tree of Knowledge (ToK) System proposed by Henriques (2003) implies that events at multiple levels of analysis (i.e., matter, life, mind, and culture) can be considered as conditions of possibility for the emergence of meaningful personal narratives. Thus, the ToK System represents an opportunity to recast the work of naturalists and social constructionists in a framework that is at once scientific and humanistic. © 2004 Wiley Periodicals, Inc. J Clin Psychol.
Justifying the Justification Hypothesis: Scientific‐humanism, Equilintegration (EI) Theory, and the Beliefs, Events, and Values Inventory (BEVI)
Authors: Shealy Craig N.
Published: November 2004

The Justification Hypothesis (JH; Henriques, 2003) is a basic, general, and macro‐level construct that is highly compelling. However, it needs greater specification (i.e., justification) regarding what it is, how it might be operationalized and measured, and what it does and does not predict in the real world. In the present analysis, the act of “justification” is conceptualized as the ongoing attempt to convince self and/or others that one's beliefs and values, which is to say one's “version of reality” or VOR, is correct, defensible, and good. In addressing these issues, this paper is divided into two complementary parts: (a) consideration of justification dynamics and exemplars from a scientific‐humanist perspective and (b) an examination of how justification systems and processes have been studied vis‐à‐vis research and theory on beliefs and values as well as an extant model—Equilintegration (EI) Theory—and method—the Beliefs, Events, and Values Inventory (BEVI). © 2004 Wiley Periodicals, Inc. J Clin Psychol.
Toward a useful mass movement
Authors: Henriques Gregg R.
Published: November 2004

Psychology has failed to reach its full potential as either a science or a profession. The inability of psychologists to generate a shared, general understanding of their subject matter and fundamental differences between scientific and nonscientific views of human behavior in society at large interact to render psychology's contributions to the world's most pressing problems much less potent than might otherwise be the case. The Tree of Knowledge (ToK) System affords new opportunities both to define the discipline of psychology and to examine the epistemological interrelations between the institution of science and other societal institutions, such as law, governance, health care, the arts, and religion. In this article I articulate how the foundation can be laid for the development of a useful mass movement that could transform the discipline of psychology in a manner that unleashes its constructive potential, while at the same time it attempts to address many of the concerns about the proposal raised by the contributors to these two special issues. © 2004 Wiley Periodicals, Inc. J Clin Psychol.
Sonography of entrapment neuropathies in the upper limb (wrist excluded)
Authors: Martinoli Carlo , Bianchi Stefano , Pugliese Francesca , Bacigalupo Lorenzo , Gauglio Cristina , Valle Maura , Derchi Lorenzo E.
Published: November 2004

The progressive refinement of broadband transducers with frequencies higher than 10 MHz and improved near‐field resolution has enhanced the potential of sonography to evaluate a variety of nerve entrapment syndromes occurring in the upper limb, such as suprascapular neuropathy in the area of the spinoglenoid‐supraspinous notch, the quadrilateral space syndrome (axillary neuropathy), radial neuropathy in the area of the spiral groove, the supinator syndrome (posterior interosseous neuropathy), the cubital tunnel syndrome (ulnar neuropathy), and the Kiloh‐Nevin syndrome (anterior interosseous neuropathy). In these settings, high‐resolution sonography can depict changes in the nerve's shape and echotexture and can depict many extrinsic causes of nerve entrapment. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:438–450, 2004
Sonography of the knee: Intra‐articular pathology
Authors: Court‐Payen Michel
Published: November 2004

MRI is the gold‐standard imaging technique for evaluation of the intra‐articular structures of the knee, and the use of sonography remains controversial. Sonography nevertheless is a useful alternative in several conditions: Inflammatory joint diseases, where it is appropriate for early diagnosis and follow‐up of joint effusion and synovitis; peri‐articular masses, where it is the best modality for guidance of needle puncture or biopsy; suspected meniscus or ligament lesion, where it may provide a positive diagnosis but is not sufficient to exclude intra‐articular lesions; and loose bodies, where it is an outstanding modality for diagnosing lesions not evident on radiographs. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:481–490, 2004
Sonography in wrist tendon pathology
Authors: Daenen Bénédicte , Houben Georges , Bauduin Emmanuel , Debry Roland , Magotteaux Paul
Published: November 2004

Wrist tendons may be affected by a variety of pathologic conditions, including those caused by trauma and overuse, inflammatory and metabolic disorders, or infection. Sonography is a very sensitive means of detecting tendinous pathology because of its spatial resolution and its comparative and dynamic capabilities. Its wide availability makes it the preferred first‐line imaging modality in the case of wrist pain. This article reviews the pathologic conditions that may involve the wrist and their sonographic appearances. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32: 462–469, 2004
Relaxation enhancing properties of MnDPDP in human myocardium
Authors: Skjold Arne , Vangberg Torgil R , Kristoffersen Anders , Haraldseth Olav , Jynge Per , Larsson Henrik B.W.
Published: November 2004

Purpose

To assess magnitude and duration of changes in myocardial longitudinal relaxation rate (R1) in humans following infusion of the manganese (Mn) releasing contrast agent MnDPDP (Mn‐dipyridoxyl‐diphosphate).

Materials and Methods

Fifteen healthy volunteers were divided into three groups. After initial myocardial and liver R1 measurements using an inversion recovery (IR) turbo fast low‐angle shot (FLASH) sequence at 1.5 Tesla, the groups were given different doses of intravenous MnDPDP: 5, 10 and 15 μmol/kg body weight, respectively, over 30 minutes. R1 measurements were then repeated at 1, 2, 4, 8, and 24 hours after the infusion ended.

Results

The left ventricular wall R1 prevalue was 0.98 second−1 (±0.04). R1 increased on average (all 15 subjects) 0.41 second−1 (±0.09). The increase was present one hour after the end of the infusion, remained relatively constant the next two hours, and then declined gradually. After 24 hours, there was still a moderate R1 elevation present, with an average R1‐value of 1.16 (±0.05). There were only small differences in myocardial R1 responses between the three doses investigated, which was contrasted by a marked dose‐response in liver tissue.

Conclusion

MnDPDP gave a significant and prolonged rise in myocardial R1 even at a dose of 5 μmol/kg. The R1‐values in the myocardium did not increase linearly with higher doses. J. Magn. Reson. Imaging 2004;20:948–952. © 2004 Wiley‐Liss, Inc.
Near‐infrared fluorescence imaging and histology confirm anomalous edematous signal distribution detected in the rat lung by MRI after allergen challenge
Authors: Tigani Bruno , Gremlich Hans‐Ulrich , Cannet Catherine , Zurbruegg Stefan , Karmouty Quintana Harry , Beckmann Nicolau
Published: November 2004

Purpose

To address the issue concerning the predominant location, on the left anatomic side, of edematous signals detected by magnetic resonance imaging (MRI) in the lungs of actively sensitized rats following intratracheal (IT) allergen challenge.

Materials and Methods

Near‐infrared fluorescence (NIRF) imaging was used to detect the lobular distribution in the lungs of normal rats of an IT instilled fluorescent dye, Cy5.5. Actively sensitized Brown Norway rats were examined by MRI 24 hours after IT administration of ovalbumin. The perivascular edema was quantified by histology in the different lobes of lungs removed from the same animals immediately after the MRI acquisitions.

Results

An uneven distribution of Cy5.5 was found, predominantly on the left lobe, paralleling the localized development of allergic pulmonary inflammation in the left lobe detected as edematous signal by MRI and confirmed by histology. The patterns of the distributions of the dye between and within the lobes were very similar to those of perivascular edema assessed histologically.

Conclusion

The data indicate a relationship between the molecular deposition of the dye detected by NIRF in the lungs and the distribution of allergen eliciting the development of pulmonary inflammation in actively rats. The combination of MRI with NIRF imaging may provide important information in preclinical pharmacologic research in the area of airway diseases. While MRI is able to address the effects of compounds on the inflammatory response in models of airways diseases, NIRF imaging may provide important insights on drug distribution and interaction in the lung, being thus suited for molecular imaging studies. J. Magn. Reson. Imaging 2004;20:967–974. © 2004 Wiley‐Liss, Inc.
Quantitative cerebral perfusion using the PRESTO acquisition scheme
Authors: Pedersen Michael , Klarhöfer Markus , Christensen Søren , Ouallet Jean‐Christophe , Østergaard Leif , Dousset Vincent , Moonen Chrit
Published: November 2004

Purpose

To evaluate the feasibility of using the rapid principles of echo shifting with a train of observations (PRESTO) sequence for measurements of cerebral hemodynamic parameters based on first pass of a contrast agent.

Materials and Methods

Simulations were performed to investigate potential resolution loss due to relaxation effects. Experimental evaluation was conducted in healthy monkey brains using PRESTO and echo‐planar imaging (EPI).

Results

For short echo trains, an insignificant contribution of the longitudinal and transversal relaxation rates to the signal amplitude in white matter and gray matter was found, whereas a contribution as large as 40% was found in large vessels. Simulations of the point spread function demonstrated that PRESTO, despite its shorter readout trains, only has a small advantage in terms of maintenance of image resolution during bolus passage compared to EPI as long as the EPI echo train can be kept similar to the T2* value at the top of the bolus. Experimental studies revealed that the PRESTO and EPI gray matter to white matter ratio were similar with respect to cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT).

Conclusion

The study showed that PRESTO and EPI led to comparable quantitative perfusion parameters. J. Magn. Reson. Imaging 2004;20:930–940. © 2004 Wiley‐Liss, Inc.
Smooth muscle tumors of uncertain malignant potential and leiomyosarcomas of the uterus: MR findings
Authors: Tanaka Yumiko Oishi , Nishida Masato , Tsunoda Hajime , Okamoto Yoshikazu , Yoshikawa Hiroyuki
Published: November 2004

Purpose

To study the MR characteristics of nonbenign uterine smooth muscle tumors.

Materials and Methods

Nine patients with pathologically proven leiomyosarcomas, and three patients with smooth muscle tumors of uncertain malignant potential (SMTUMP) were included in this study. Twelve cases of benign uterine leiomyomas and variants, in which gynecologists suspected leiomyosarcomas, were also analyzed. In each case we studied the size, location, signal intensity, and contrast enhancement of the tumors.

Results

Nine of the 12 nonbenign characters had more than 50% of high‐intensity areas on T2‐weighted images (T2WI), and some hyperintense foci on T1‐weighted images (T1WI). In the contrast study, nine of 12 nonbenign characters had well‐demarcated unenhanced areas. On the other hand, only two of 12 benign characters showed such a signal intensity pattern, and none of them had a pocket‐like unenhanced area.

Conclusion

Although there were some exceptions, more than 50% of high signal on T2WI, and the presence of any small high‐signal areas on T1WI with unenhanced pockets were considered MR‐suggestive for SMTUMPs and leiomyosarcomas. J. Magn. Reson. Imaging 2004;20:998–1007. © 2004 Wiley‐Liss, Inc.
Three‐dimensional MR angiography in imaging platinum alloy stents
Authors: Trost David W. , Zhang Hong Lei , Prince Martin R. , Winchester Priscilla A. , Wang Yi , Watts Richard , Sos Thomas A.
Published: November 2004

Purpose

To evaluate visualization inside platinum stents with three‐dimensional contrast‐enhanced magnetic resonance angiography (CE‐MRA).

Materials and Methods

Breath‐hold three‐dimensional gadolinium (Gd) MRA was performed on 18 patients with 22 platinum stents in the renal (n = 18), celiac (n = 1), superior mesenteric (n = 1), and iliac (n = 2) arteries. Electronic calibers were used to measure the lumen diameter within the stent and just distal to the stent to calculate percent stenosis. MRA accuracy was determined from the difference between percent stenosis measured on MRA and digital subtracted angiography (DSA). The patients were imaged at flip angles of 45°, 60°, 75°, 90°, and 150°.

Results

MRA demonstrated the stent lumen in all of the patients, with a mean difference between MRA and DSA of 21%. For stents oriented parallel to B0 (iliac arteries) the difference was only 10%, as compared to 22% for stents perpendicular to B0. The flip angle with the best agreement between MRA and DSA was 75° (16%).

Conclusion

The lumen of a platinum stent can be imaged with three‐dimensional CE‐MRA, although grading of restenosis has limited accuracy. The best results were obtained with a flip angle of 75° and for stents in the iliac arteries parallel to B0. J. Magn. Reson. Imaging 2004;20:975–980. © 2004 Wiley‐Liss, Inc.
Muscle kinematics during isometric contraction: Development of phase contrast and spin tag techniques to study healthy and atrophied muscles
Authors: Sinha Shantanu , Hodgson John A. , Finni Taija , Lai Alex M. , Grinstead John , Edgerton V. Reggie
Published: November 2004

Purpose

To develop and compare phase‐contrast (PC) and spin‐tag (ST) MR imaging techniques for accurate quantification of velocity and displacement distribution in the muscle tendon complex of the lower leg during isometric contractions under in vivo conditions, in healthy subjects and subjects with atrophy.

Materials and Methods

Techniques were developed to acquire PC and ST dynamic images, gated to the force exerted by a subject during isometric contraction. Algorithms were optimized for correction of phase shading errors. Flow velocity quantification was validated in phantoms and ex vivo rabbit muscles. Trajectories of pixels calculated from PC images were compared with those in ST images. Velocity distributions were determined in healthy muscles, those atrophied by four weeks of suspension, and during physiotherapy‐induced recovery.

Results

The technique developed allowed acquisition of images retrospectively gated to the isometric contraction performed with the subject in the scanner. Significant phase shading errors in PC images (≈3 cm/second over the field of view) were reduced to the background noise level by the correction algorithm. Tissue trajectories calculated from PC images agreed very well with those from ST images both in human and excised animal tissues. Peak velocities in atrophied muscles were significantly lower compared to the preatrophy state but recovered to baseline values after six weeks of therapy.

Conclusion

We show the feasibility of monitoring muscle velocity and tissue displacement during voluntary contractions in humans under in vivo conditions using MR tissue motion mapping methods. The clinical feasibility of this technique in monitoring atrophied muscle is also demonstrated. J. Magn. Reson. Imaging 2004;20:1008–1019. © 2004 Wiley‐Liss, Inc.
High‐resolution, multicontrast three‐dimensional‐MRI characterizes atherosclerotic plaque composition in ApoE–/– mice ex vivo
Authors: Schneider Jürgen E. , McAteer Martina A. , Tyler Damian J. , Clarke Kieran , Channon Keith M. , Choudhury Robin P. , Neubauer Stefan
Published: November 2004

Purpose

To systematically investigate intrinsic MR contrast mechanisms that would facilitate plaque characterization and quantification in the aortic root and brachiocephalic artery of ApoE–/– mice ex vivo.

Materials and Methods

To establish unambiguous MR parameters for routinely analyzing atherosclerotic plaque ex vivo at 11.7 T, relaxation times of plaque components were quantitatively assessed. Magnetization transfer and lipid‐proton three‐dimensional MR imaging was investigated for visualization of collagen‐ and lipid‐rich plaque regions, respectively. A three‐dimensional multiecho sequence with a spatial resolution of 47 × 47 × 63 μm was implemented providing a variable degree of T2‐weighting.

Results

Relaxation time measurements showed clear tissue heterogeneity between atherosclerotic plaque components in the T2‐values, but similar T1‐values at 11.7 T (T1/T2 mean ± SD; cellular plaque component: 1.2 ± 0.3 seconds/26.3 ± 0.4 msec; fibrofatty plaque component: 1.1 ± 0.2 seconds/13.7 ± 2.0 msec). The three‐dimensional multiecho sequence allowed the calculation of the intrinsic proton density and T2‐maps. The sum of the multiecho data provided strong T2‐weighting that facilitated quantification of various components of atherosclerotic plaque in the mouse aortic root and correlated well with histology (P < 0.0001).

Conclusion

High‐resolution MRI allows for accurate classification and quantification of atherosclerotic plaque components in the aortic root of mice. J. Magn. Reson. Imaging 2004;20:981–989. © 2004 Wiley‐Liss, Inc.
Neurochemistry of late‐life major depression: A pilot two‐dimensional MR spectroscopic study
Authors: Binesh Nader , Kumar Anand , Hwang Sun , Mintz Jim , Thomas M. Albert
Published: November 2004

Purpose

To evaluate a two‐dimensional localized chemical shift correlated spectroscopy (L‐COSY) sequence in elderly patients with major depression.

Materials and Methods

A total of 33 healthy elderly subjects and 15 elderly patients with major depression were investigated. A voxel size of 3 × 3 × 3 cm3 was chosen in the dorsolateral prefrontal region with predominantly white matter, with the use of three slice‐selective radiofrequency (RF) pulses (90°, 180°, and 90°). A chemical shift‐selective (CHESS) sequence was used prior to volume localization for the presaturation of water. The two‐dimensional raw data matrix consisted of 1024 complex points along the detection period (t2), and 100 increments along the evolution period (t1), resulting in a total acquisition time of approximately 27 minutes per acquisition. The metabolite ratios were calculated using the two‐dimensional peak volumes with respect to the diagonal peak volume of total creatine (Cr) at 3.0 ppm.

Results

In the 33 elderly subjects, the mean ratio of choline (Cho) to Cr was 10% higher in men compared to women (P < 0.05), consistent with earlier findings obtained by one‐dimensional MRS. When the metabolite ratios were compared in a subsample of 16 elderly female controls and 12 depressed female patients, the depressed geriatric patients had higher levels of myoinositol (mI), phosphoethanolamine (PE), and glutamate/glutamine (Glx) than the controls, although the differences were not statistically significant.

Conclusion

Our pilot study shows the feasibility of performing two‐dimensional L‐COSY successfully in elderly subjects and patients with late‐life mood disorders. These findings are consistent with and expand on our earlier findings in major depressive disorder (MDD) detected with one‐dimensional MRS. J. Magn. Reson. Imaging 2004;20:1039–1045. © 2004 Wiley‐Liss, Inc.
Nitrate stability in loess soils under anaerobic conditions—laboratory studies
Authors: Włodarczyk Teresa , Stępniewski Witold , Brzezińska Małgorzata , Stępniewska Zofia
Published: November 2004

The objective of this laboratory study with six loess soils (three Eutric CambisoIs and three Haplic Phaeozems) incubated under flooded conditions was to examine the effect of a wide range of NO$ _3^- $ doses under anaerobic conditions on soil redox potential and N2O emission or absorption. Due to the fact that loess soils are usually well‐drained and are expected to be absorbers during prevailing part of the season, the study aimed at determination of the conditions decisive for the transition from emission to absorption process. On the basis of the response to soil nitrate level, the two groups of soils were distinguished with high and low denitrification capacity. The soil denitrification activity showed Michaelis‐Menten kinetics with respect to soil nitrate content with KM in the range 50–100 mg NO$ _3^- $‐N kg–1. Percentage of nitrates converted to N2O increased linearly with nitrate concentration in the range from 25 to 100 mg NO$ _3^- $‐N kg–1 up to 43% and decreased linearly at higher concentrations reaching practically zero at concentrations about 600 mg NO$ _3^- $‐N kg–1. No denitrification was observed below 25 mg NO$ _3^- $‐N kg–1. Nitrous oxide absorption in soil occurred only at nitrate concentrations to 100 mg NO$ _3^- $‐N kg–1 and in this concentration range was proportional to the denitrification rate. Nitrous oxide was formed at redox potentials below +200 mV and started to disappear at negative Eh values.
Limits imposed by salt to the growth of the halophyte Sesuvium portulacastrum
Authors: Messedi Dorsaf , Labidi Nehla , Grignon Claude , Abdelly Chedly
Published: November 2004

The growth of the halophyte Sesuvium portulacastrum, commonly known as sea purslane, is impeded by NaCl only at high (600–1000 mM) concentration. Therefore, the goal of this investigation was to identify the mechanisms which set the limit of the salt resistance of S. portulacastrum. 21‐day‐old cuttings were grown for 45–50 d under split‐root conditions in which one half of the root system was immersed in complete nutrient solution supplemented with 800 mM NaCl, while the other half was immersed in a NaCl‐free medium, containing all nutrients or being deprived of potassium or calcium or nitrogen. Using this approach, we demonstrate that K+ and N uptake was impaired in roots exposed to NaCl. Concerning Ca2+, there was no indication of uptake inhibition by NaCl. However, restriction of K+ uptake by roots was compensated by an increase in the K+‐use efficiency, so that growth was not inhibited. Concerning N, our analysis shows that NO$ _3^- $ and/or NH$ _4^+ $ uptake, but not their assimilation, was limited by salt treatment. Thus, we conclude that at high salinity levels, the growth of S. portulacastrum is limited by the restrictions imposed by NaCl on N uptake, perhaps in addition to inhibiting effects of excessive Na+ accumulation in shoot.
Reaktion der Zuckerrübe (Beta vulgaris var. altissima) auf die Kaliumdüngung – ein 20‐jähriger Feldversuch
Authors: Römer Wilhelm , Claassen Norbert , Steingrobe Bernd , Märländer Bernward
Published: November 2004

Die Untersuchungen hatten das Ziel, in einer Zuckerrrüben‐Weizen‐Gerste‐Fruchtfolge auf einem Auenboden (toniger Schluff) in Südniedersachsen eine K‐Düngungsstrategie für hohe und stabile Erträge (hier fokussiert auf die bereinigten Zuckererträge = BZE) zu erarbeiten. Hierzu gab es, bei generellem Verbleib von Stroh und Rübenblatt auf dem Feld, seit 1983 folgende Kalium‐Düngungsvarianten: 1) jährliche K‐Zufuhr in Höhe des 0‐, 0,5‐, 1‐, 1,5‐, 3‐ und 9fachen Ersatzes der einfachen mittleren jährlichen K‐Abfuhr (0, 29, 58, 87, 174 bzw. 524 kg K ha–1 a–1), wobei die Parzellen mit dem 3‐ bzw. 9fachen Ersatz seit 1995 nur noch je 174 kg K ha–1 alle 3 Jahre erhielten (Fruchtfolge‐Düngung); 2) die jährliche K‐Gabe (58 kg K ha–1) mit einer 3‐jährlichen K‐Gabe (174 kg K ha–1); 3) die jährliche K‐Gabe (87 kg K ha–1) als Applikation im Herbst oder Frühjahr; 4) die jährliche K‐Gabe in mineralischer oder in „organischer”︁ Form als Ganzpflanzenrecycling (Korn plus Stroh, Rüben plus Blatt) und 5) die Applikation einer zusätzlichen NaCl‐Gabe (29 kg ha–1) zur einfachen K‐Gabe (58 kg ha–1) vor den Zuckerrüben.

Die Rübenerträge stiegen bis zur höchsten K‐Gabe an, bei gleichzeitigem Anstieg der lactatlöslichen Boden‐K‐Gehalte. Die bereinigten Zuckergehalte erreichten bei einer jährlichen K‐Gabe von 174 kg K ha–1 ihr Maximum. Der BZE stieg im Mittel aller Versuchsjahre bis zur höchsten jährlichen K‐Gabe an. Es gab keinen Unterschied in der K‐Düngewirkung in Bezug auf den BZE zwischen Herbst‐ und Frühjahrsdüngung. Kalium aus Mineraldünger und organischem Material hatte ähnliche Wirksamkeit. Eine zusätzliche NaCl‐Gabe erhöhte den BZE nur in einzelnen Jahren um wenige Prozentpunkte. Als ökonomisch empfehlenswert ergab sich eine K‐Fruchtfolgedüngung vor den Zuckerrüben in Höhe von 174 kg K ha–1. Mit niedrigprozentigen Kali‐Salzen kann der NaCl‐Effekt nutzbar gemacht werden. Der lactatlösliche K‐Gehalt im Grenzbereich der Gehaltsklassen B/C (ca. 110 mg K (kg Boden)–1) ist für den geprüften Standort ausreichend für hohe BZE.
Depletion of non‐exchangeable NH$ _4^+ $ at the root–soil and hyphae–soil interface of VA mycorrhizal maize (Zea mays) and parsley (Petroselinum sativum)
Authors: Scherer Heinrich W. , Frost Maren
Published: November 2004

Mobilization of non‐exchangeable ammonium (NH$ _4^+ $) by hyphae of the vesicular‐arbuscular mycorrhizal (VAM) fungus Glumus mosseae was studied under controlled experimental conditions. Maize (Zea mays) and parsley (Petroselinum sativum) were grown either alone or in symbiosis with Glomus mosseae in containers with separated compartments for roots and hyphal growth. In one experiment, 15NH$ _4^+ $ was added to the soil to differentiate between the native non‐exchangeable NH$ _4^+ $ and the non‐exchangeable NH$ _4^+ $ derived from N fertilization. Non‐exchangeable NH$ _4^+ $ was mobilized by plant growth. Plant dry weight and N uptake, however, were not significantly influenced by mycorrhizal colonization of the roots. The influence of root infection with mycorrhizal fungus on the mobilization of non‐exchangeable NH$ _4^+ $ was negligible. In the hyphal compartment, hyphal uptake of N resulted in a decrease of NH$ _4^+ $ in the soil solution and of exchangeable NH$ _4^+ $. However, the NH$ _4^+ $ concentration was still too high to permit the release of non‐exchangeable NH$ _4^+ $. The results demonstrate that, in contrast to roots, hyphae of VAM fungi are not able to form a non‐exchangeable‐NH$ _4^+ $ depletion zone in the adjacent soil. However, under conditions of a more substantial depletion of the exchangeable NH$ _4^+ $ in the mycorrhizal sphere (e.g., with longer growth), an effect of mycorrhiza on the non‐exchangeable NH$ _4^+ $ might be found.
Application of ground‐penetrating radar to determine the thickness of Pleistocene periglacial slope deposits
Authors: Sauer Daniela , Felix‐Henningsen Peter
Published: November 2004

Wide areas of the mountainous regions of Germany have rock covered by Pleistocene periglacial slope deposits (PPSD), formed by gelifluction during the cold periods of the ice ages in non‐glaciated areas. The PPSD provide the parent material for soil development, and their physical characteristics affect several stabile soil properties. Because the PPSD play a significant ecological role, we studied the spatial distribution and properties of the PPSD in order to assess the distribution of the stabile soil properties. The high stone content of the PPSD greatly hinders augering and digging. Hence, we tested the use of ground‐penetrating radar (GPR) as a potentially time‐saving, non‐destructive method to determine the thickness of the PPSD. In several study areas of the Rhenish Massif, GPR investigations of single soil profiles and soil transects along an exposed gas‐pipeline ditch were carried out. The GPR images were compared to the actual thickness of the layers of the PPSD exposed in the profiles and the ditch. In the GPR images usually at least one distinct boundary could be identified, which occurs at the transition between the loose material and the hard rock, mostly ranging between 50 and 150 cm depth. In some cases, in which stone content changed abruptly between different layers of the PPSD, also the boundaries between these layers could be identified in the GPR image. On the other hand, in areas where remnants of the Mesozoic‐Tertiary weathering mantle are preserved, the boundary between the saprolite and the overlying basal layer of the PPSD is ambiguous or not at all visible.
Predictions of soil water and crop growth dynamics using the agroecosystem models THESEUS and OPUS
Authors: Wegehenkel Martin , Mirschel Wilfried , Wenkel Karl‐Otto
Published: November 2004

The agroecosystem models THESEUS and OPUS were tested with data obtained from three agricultural experimental field plots on sandy soils without groundwater located at the moraine landscape in East Brandenburg, Germany. At each of these plots, a separate agricultural management practice was applied. Measurements of soil water contents, pressure heads, above‐ground crop biomass, and crop yield from these three plots were compared with the corresponding simulation results of both models. The comparisons of simulated with measured outputs were analyzed using the modeling‐efficiency index IA. According to these analyses, both models simulated adequately the time courses of volumetric soil water contents and above‐ground crop biomass, but the time courses of pressure heads were predicted with a lower quality by both models. As for the pressure heads, the yields simulated with both models showed greater discrepancies in comparison with the observed ones. This indicates the need of a site‐specific parameter calibration of the crop‐growth modules, especially for that included in OPUS.
Combined orthotopic heart and liver transplantation: The need for exception status listing1 †
Authors: Porrett Paige M. , Desai Shashank S. , Timmins Kathleen J. , Twomey Carol R. , Sonnad Seema S. , Olthoff Kim M.
Published: November 2004

Through May 2004, 33 combined orthotopic heart-liver transplants (OHT/OLT) have been performed nationwide. No published data exist to date regarding outcomes of patients awaiting such transplants, although progression of two organ disease processes may contribute to premature death for waiting patients. Retrospective data were collected on patients listed for combined OHT/OLT from both an individual tertiary care transplant center and the national UNOS registry to delineate listing criteria and evaluate patient outcomes in both the pre- and post-MELD eras. All patients who survived to transplantation or died on the waiting list were included in the analysis. Results show that 29.6% of patients registered nationally and 42% of patients listed institutionally survived to transplantation. Survival to transplantation was associated with less severe liver disease, though patients with MELD scores ranging from 19 to 26 had significantly higher wait list mortality than expected when compared to single-organ liver transplants. Following combined orthotopic heart-liver transplantation, 80% and 70% of patients survive 1 and 3 years, respectively. In conclusion, combined OHT/OLT is a successful therapy, but current organ allocation policies may not ensure expeditious transplantation in critically ill patients with dual vital organ failure. Providing exception status listing to these patients would ensure more expeditious transplantation and potentially contribute to improved survival. (Liver Transpl 2004;10:1539-1544.)
Hepatocellular proliferation and changes in microarchitecture of right lobe allografts in adult transplant recipients†
Authors: Huang Ruoqing , Schiano Thomas D. , Amolat May Jennifer , Miller Charles M. , Thung Swan N. , Saxena Romil
Published: November 2004

Imaging studies show complete restoration of liver volume in adult recipients of right lobe allografts within 2-3 weeks of living donor transplantation (LDLT). However, it is not known if this growth is associated with restoration of hepatic microarchitecture. We compared 21 biopsies without significant pathology from LDLT recipients with 23 biopsies from adult recipients of cadaveric donor liver transplantation (CDLT) performed within 3 months of transplantation. The difference in the number of portal tracts per cm was statistically significant (P < .0001) between CDLT (9.08 ± 1.74) and LDLT recipients within 3 months (6.26 ± 1.62), as well as after 3 months following transplantation (6.56 ± 1.44). The coefficient of correlation between length of biopsy specimens and the number of portal tracts in these 3 groups was .94, .93, and .85, respectively. Proliferative activity demonstrated by immunohistochemical staining for MIB-1 was seen predominantly in hepatocytes in both groups; bile ducts only occasionally stained positive. The difference between labeling indices of hepatocytes was statistically significant (P = .00056) between CDLT and LDLT recipients within 3 months of transplantation (.82 ± .63 and 4.53 ± 3.72), and between LDLT recipients within 3 weeks and after 3 weeks of transplantation (5.97 ± 3.78 and 1.80 ± 1.37, P = .0074). In conclusion, restoration of liver volume following LDLT occurs by proliferation of hepatocytes in the immediate posttransplant period. There is a decrease in number of portal tracts in these volume-restored allografts. Volume restoration is therefore, not accompanied by restoration of hepatic microarchitecture. (Liver Transpl 2004;10:1461-1467.)
Analysis of a successful HCV-specific CD8+ T cell response in patients with recurrent HCV-infection after orthotopic liver transplantation† ‡
Authors: Gruener Norbert Hubert , Jung Maria-Christina , Ulsenheimer Axel , Gerlach Joern Tilman , Zachoval Reinhart , Diepolder Helmut Michael , Baretton Gustavo , Schauer Rolf , Pape Gerd Rudolf , Schirren Carl Albrecht
Published: November 2004

Virus-specific CD8+ T cells play a major role in antiviral immune defenses; their significance in the transplant setting, however, is unclear. In the present study, we asked whether hepatitis C virus (HCV)-specific CD8+ T cells were detectable in the presence of an immunosuppressive treatment and whether the HCV-specific CD8+ T cell response correlates with treatment outcome in patients who receive interferon (IFN)-α / ribavirin therapy after orthotopic liver transplantation (OLTx). Liver- and blood-derived T cell lines of 21 patients after OLTx were studied before, at the end of, and after antiviral treatment. Virus-specific IFN-γ production in response to a panel of previously identified HCV-specific epitopes restricted by the human leukocyte antigen (HLA) class I molecules A2, A3, B7, B35, and B44 of structural and nonstructural HCV protein was determined by enzyme-linked immunospot (ELISPOT) assay. Before treatment, only low numbers of HCV-specific CD8+ T cells were detectable. In 6 patients with a sustained virological response, a significant, multispecific, and sustained CD8+ T cell response was detectable, which was mainly found in the peripheral blood. Nonresponders and transient responders showed undetectable, weak, or transient HCV-specific CD8+ T cell responses. (Sustained responders vs. transient and nonresponders: Wilcoxon rank-signed test; P < .01). In conclusion, our data indicate that despite immunosuppression, HCV-specific CD8+ T cells are detectable in patients with recurrent HCV infection after OLTx and that a significant, multispecific, and long-lasting HCV-specific CD8+ T cell response contributes to viral elimination. (Liver Transpl 2004;10:1487-1496.)
Factors that identify survival after liver retransplantation for allograft failure caused by recurrent hepatitis C infection
Authors: Neff Guy W. , O’Brien Christopher B. , Nery Jose , Shire Norah J. , Nishida Seigo , delaGarza Julia , Montalbano Marzia , Safdar Kamran , Ruiz Phillip , Rideman Eric , Gascon Jose A. , Tzakis Andreas G. , Madariaga Juan , Rudich Steven M.
Published: November 2004

Hepatitis C virus (HCV) is becoming the most common indication for liver retransplantation (ReLTx). This study was a retrospective review of the medical records of liver transplant patients at our institution to determine factors that would identify the best candidates for ReLTx resulting from allograft failure because of HCV recurrence. The patients were divided into 2 groups on the basis of indication for initial liver transplant. Group 1 included ReLTx patients whose initial indication for LTx was HCV. Group 2 included patients who received ReLTx who did not have a history of HCV. We defined chronic allograft dysfunction (AD) as patients with persistent jaundice (> 30 days) beginning 6 months after primary liver transplant in the absence of other reasons. HCV was the primary indication for initial orthotopic liver transplantation (OLT) in 491/1114 patients (44%) from July 1996 to February 2004. The number of patients with AD undergoing ReLTx in Groups 1 and 2 was 22 and 12, respectively. The overall patient and allograft survival at 1 year was 50% and 75% in Groups 1 and 2, respectively (P = .04). The rates of primary nonfunction and technical problems after ReLTx were not different between the groups. However, the incidence of recurrent AD was higher in Group 1 at 32% versus 17% in Group 2 (P = .04). Important factors that predicted a successful ReLTx included physical condition at the time of ReLTx (P = .002) and Child-Turcotte-Pugh score (P = .008). In conclusion, HCV is associated with an increased incidence of chronic graft destruction with a negative effect on long-term results after ReLTx. The optimum candidate for ReLTx is a patient who can maintain normal physical activity. As the allograft shortage continues, the optimal use of cadaveric livers continues to be of primary importance. The use of deceased donor livers in patients with allograft failure caused by HCV remains a highly controversial issue. (Liver Transpl 2004;10:1497-1503.)
Expanded criteria donor grafts for deceased donor liver transplantation under the MELD system: A decision analysis
Authors: Amin Manish G. , Wolf Michael P. , TenBrook John A. , Freeman Richard B. , Cheng Steve J. , Pratt Daniel S. , Wong John B.
Published: November 2004

Expanded criteria donor (ECD) liver grafts have a higher likelihood of primary graft failure (PGF) compared with standard criteria donor (SCD) grafts. Given a choice between an available ECD graft versus waiting for an SCD graft that may not always become available, what should liver transplant candidates do? The study’s aim was to estimate 1-year survival comparing immediate ECD liver grafting with waiting for an SCD organ. Using UNOS data, published literature estimates, and expert opinion, we constructed a Markov decision analytic model to estimate survival while waiting for an SCD transplant and survival with immediate ECD transplant. Sensitivity analyses were performed by varying model parameters individually and simultaneously with a second-order Monte Carlo simulation. For all patients with MELD scores >20, survival was higher with immediate ECD transplant despite the additional increased risk for PGF. Survival was better with an immediate ECD transplant unless the probability of PGF exceeded 23%, 72%, and 88% for recipients with MELD scores of 11-20, 21-25, and 26-30 respectively. For patients with MELD scores >30, the survival benefit with the immediate ECD strategy persisted at even higher rates of PGF. In conclusion, our results suggest that, despite the higher risk for PGF, transplantation with an available ECD graft should be preferred over waiting for an SCD organ for patients with advanced MELD scores. At less advanced MELD scores, the survival benefit depends on the risk of PGF associated with the ECD organ. (Liver Transpl 2004;10:1468-1475.)
Determination of the optimal model for end-stage liver disease score in patients with small hepatocellular carcinoma undergoing loco-regional therapy
Authors: Huo Teh-Ia , Wu Jaw-Ching , Lin Han-Chieh , Lee Fa-Yauh , Hou Ming-Chih , Huang Yi-Hsiang , Lee Pui-Ching , Chang Full-Young , Lee Shou-Dong
Published: November 2004

The model for end-stage liver disease (MELD) has been a prevailing system to prioritize cirrhotic patients awaiting liver transplantation. An “exceptional” MELD score of 20 and 24 points is assigned for stage T1 and T2 patients with small hepatocellular carcinoma (HCC), respectively. However, this strategy is based on scarce data and the optimal score for these patients remains uncertain. We investigated 238 patients with small HCC who were candidates for liver transplantation and underwent arterial chemoembolization or percutaneous injection therapy using acetic acid or ethanol. Tumor stage (P = .001) and Child-Turcotte-Pugh (CTP) class (P < .001) were independent risk factors predicting tumor progression or death in survival analysis. The risk of disease progression in HCC patients stratified by tumor stage was mapped and equated with the risk of mortality of 456 cirrhotic patients without HCC. The 6- and 12-month rates of disease progression were 4% and 6%, respectively, for stage T1 HCC patients (n = 50; mean MELD: 9.5). These rates were close to and no higher than the mortality rate in MELD category 8-12 at the corresponding time period (7.1% and 11.3%, respectively; n = 141). For stage T2 patients (n = 188; mean MELD: 9.3), the corresponding rates were 5.3% and 13.8%, respectively, which were close to and no higher than the mortality rate in MELD category 10-14 (9.0% and 13.9%, respectively, n = 166). In conclusion, the risk of disease progression is quite low for selected HCC patients undergoing loco-regional therapy. A lower MELD score may be suggested to be equivalent to the risk of short- and mid-term mortality in the cirrhosis group. (Liver Transpl 2004;10:1507-1513.)
A time domain FEM approach based on implicit Green's functions for non‐linear dynamic analysis
Authors: Soares D. , Mansur W. J.
Published: November 2004

The present paper describes an unconditionally stable algorithm to integrate the equations of motion in time. The standard FEM displacement model is employed to perform space discretization, and the time‐marching process is carried out through an algorithm based on the Green's function of the mechanical system in nodal co‐ordinates. In the present ‘implicit Green's function approach’ (ImGA), mechanical system Green's functions are not explicitly computed; rather they are implicitly considered through an iterative pseudo‐forces process. Under certain simplifying hypothesis, iterations are not necessary and the ImGA becomes cheaper than standard Newmark/Newton–Raphson algorithm. At the end of the paper numerical examples are presented in order to illustrate the accuracy of the present approach. Copyright © 2004 John Wiley & Sons, Ltd.