bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional and species specific bioaccumulation of major and trace elements in Arctic seabirds
Authors: Borgå Katrine , Campbell Linda , Gabrielsen Geir W. , Norstrom Ross J. , Muir Derek C.G. , Fisk Aaron T.
Published: October 2006

Twenty-five essential and nonessential elements were analyzed in Arctic seabirds to study the influence of phylogeny, tissue, Arctic region, and diet on avian element accumulation and to identify co-occurrence among metals. Muscle and liver concentrations were positively correlated, generally being higher in liver than in muscle, and generally did not differ by sex. Zinc showed the highest absolute concentrations in all samples (mean, 11.2–26.7 μg/g in muscle, depending on species and area), followed by copper (5.2–7.5 μg/g), arsenic (0.5–5.4 μg/g), selenium (1.0–5.8 μg/g), rubidium (1.4–2.2 μg/g), and cadmium (0.04–1.2 μg/g). Mercury levels ranged from 0.05 to 0.8 μg/g in muscle. The concentrations varied among species (dovekie [Alle alle], black guillemot [Cepphus grylle], thick-billed murre [Uria lomvia], black-legged kittiwake [Rissa tridactyla], northern fulmar [Fulmaris glacialis], ivory gull [Pagophila eburnean], Thayer's gull [Larus thayeri], and glaucous gull [Larus hyperboreus]), and between the northern Baffin Bay (Canada) and the Barents Sea, depending on the element. Whereas some elements (e.g., mercury and zinc) increased in absolute and standardized concentrations with trophic level in the northern Baffin Bay, most elements showed no relationship with trophic level or other dietary descriptors. In absolute concentrations, nonessential elements differed between regions, whereas essential elements differed among species but not within a species across the two regions. Standardized concentrations (element pattern) of both essential elements and nonessential elements generally did not differ between regions but was highly species specific and, thus, determined by the phylogenetic element regulation capacity. The usefulness of multivariate ordination in element wildlife studies is illustrated, which provides additional insight regarding element co-occurrence in wildlife, allows inclusion of species with low sample number, and reduces the possibility of type II errors created by low sample size.
Assessment of stress-related gene expression in the heavy metal-exposed nematodeCaenorhabditis elegans: A potential biomarker for metal-induced toxicity monitoring and environmental risk assessment
Authors: Roh Ji-Yeon , Lee Junho , Choi Jinhee
Published: October 2006

The toxicity of cadmium, lead, chromium, and arsenite on Caenorhabditis elegans was investigated to identify sensitive biomarkers for environmental monitoring and risk assessment. Effects of these metals on stress-related gene expression, growth, reproduction, and mortality of C. elegans were investigated under laboratory conditions. The possibility of using C. elegans as a biosensor for environmental toxicity monitoring was also tested using a green fluorescent protein transgenic nematode. The 24-h median lethal concentrations of cadmium, lead, chromium, and arsenite in C. elegans were 846, 34, 115, and 92 mg/L, respectively. Cadmium exposure led to an increase in the expression of most of the genes tested. The degree of increase was more than threefold compared to control in heat shock protein 16.2, heat shock protein 70, metallothionein 2, cytochrome P450 family protein 35A2, glutathione-S-transferase 4, superoxide dismutase 1, catalase 2, C. elegans p53-like protein 1, and apoptosis enhancer 1 genes. The lead-, chromium-, and arsenite-exposed nematode, on the other hand, showed little change in gene expression. Alterations in growth and reproduction were observed in cadmium- and chromium-exposed worms. To consider a transgenic nematode as a biosensor for toxicity monitoring, the responses of stress-related gene promoters need to be tested with a variety of metals. The overall results suggest that cadmium exhibits a high level of tolerance compared to the other metals tested. Use of the responses of stress-related gene expression therefore has considerable potential as a sensitive biomarker for the diagnosis of cadmium contamination, and C. elegans seems to be a good biological model for this approach.
Desorption resistance of polycyclic aromatic hydrocarbons and duration of exposure
Authors: Chai Yunzhou , Kochetkov Alexander , Reible Danny D.
Published: October 2006

The desorption-resistant fraction of laboratory-spiked phenanthrene in two Louisiana (USA) sediments was not observed to be significantly different, but the two sediments exhibited different condensed-phase organic carbon contents, as defined operationally by the organic carbon remaining after combustion of the sediment at 375°C. Only 3% of the original saturated phenanthrene in the sediments was not readily removed by exposure to a nonpolar polymeric resin and sorbent XAD-2. Allowing the laboratory-spiked contaminants to age for periods of up to three years yielded little difference in the desorption-resistant characteristics of the sediments. Field-contaminated sediments from Utica Harbor (Utica, NY, USA) and Rouge River (Detroit, MI, USA) that had a lengthy (decades to a century) period of contamination, however, exhibited significantly different desorption-resistant contaminant fractions, consistent with the fractions of condensed-phase organic carbon in the sediments. Measurements of the fraction that could be rapidly desorbed using the XAD-2 sorbent also accounted for essentially all desorption to pore water and, thus, provided a good prediction of effective bulk partition coefficients. It was concluded that the condensed-phase organic carbon was a good indicator of the potential for desorption resistance in field-contaminated sediments and that the rapidly desorbing fraction provided a quantitative indicator of its significance.
Development and application of oxygen production rate assessment to uptake of fluorinated organics byLemna minor
Authors: Reinhold Dawn Marie , Saunders F. Michael
Published: October 2006

The effects of contaminant concentration on contaminant removal by Lemna minor were examined under elevated plant densities typical of full surface coverage. Uptake of 3-fluorophenol and 3-trifluoromethylphenol by L. minor was determined at concentrations from 10 to 1,750 μM. Because standardized toxicity tests typically do not measure plant activity of L. minor at high plant densities, an oxygen production rate (OP) assessment was developed with consideration of experimental parameters that may inhibit OP by L. minor, including concentrations of carbonate and phosphate buffer in the media, time of assessment, and mass of L. minor. The OP by L. minor was inhibited by increasing media pH and mass of L. minor. The developed assessment used 0.5 g of L. minor per 60 ml of modified Standard Methods medium. A total of 30 h was needed to determine toxicity of fluorinated phenols, with an exposure period of 24 h, an incubation time of 6 h, and negligible analysis time. At concentrations from 10 to 1,750 μM, 3-trifluoromethylphenol exhibited a sigmoidal toxicity response. However, 3-fluorophenol was neither toxic nor inhibitory at the experimental concentrations tested. Substantial decreases in uptake rate constants were observed for increasing concentrations of both contaminants, indicating that concentration may be a more important indicator of uptake by L. minor compared with decreasing plant activity because of toxicity.
Photoactivated polycyclic aromatic hydrocarbon toxicity in medaka (Oryzias latipes) embryos: Relevance to environmental risk in contaminated sites
Authors: Diamond Stephen A. , Mount David R. , Mattson Vincent R. , Heinis Larry J. , Highland Terry L. , Adams Andy D. , Simcik Matthew F.
Published: October 2006

The hazard for photoactivated toxicity of polycyclic aromatic hydrocarbons (PAHs) has been clearly demonstrated; however, to our knowledge, the risk in contaminated systems has not been characterized. To address this question, a median lethal dose (LD50) for fluoranthene photoactivated toxicity in medaka (Oryzias latipes) embryos was determined experimentally and then compared with ultraviolet-A (UV-A; 320–400 nm) radiation exposures in a PAH-contaminated field site. The dose metric, J/cm2/μg fluoranthene/g egg wet weight, provided the means to estimate risk as the depth where the LD50 level would be exceeded at realistic field PAH concentrations, based on estimates of UV-A exposure. The estimates were made using 30 years of solar radiation data for Duluth (MN, USA) and measurements of water-column UV-A transmittance in a PAH-contaminated field site. Medaka embryo failure was strongly related to tissue PAH concentration and UV-A exposure. The LD50 was estimated to be 12.64 J/cm2/μg fluoranthene/g egg wet weight; the 95% confidence interval was 8.46 to 19.7 J/cm2/μg fluoranthene/g egg wet weight. Embryo failures were characterized by undifferentiated cell proliferation that occurred very early in development. No partial effects or embryo/larval malformations were observed. Estimates of the depth at which the LD50 would be exceeded in the contaminated field site ranged from 10.7 cm (clear-sky conditions and lowest attenuation) to 0.0 cm (cloudy conditions and highest attenuation). Similar calculations were done using water-column attenuation estimates from 12 sites across the Great Lakes (USA). For these, the depths at which the LD50 would be exceeded ranged from 0.00 to 271.6 cm under the conditions described above. These results suggest that PAH phototoxicity may be a risk factor in specific contaminated sites, and they provide a framework for assessing that risk.
Impacts of aircraft deicer and anti-icer runoff on receiving waters from Dallas/Fort worth International Airport, Texas, USA
Authors: Corsi Steven R. , Harwell Glenn R. , Geis Steven W. , Bergman Daniel
Published: October 2006

From October 2002 to April 2004, data were collected from Dallas/Fort Worth (DFW) International Airport (TX, USA) outfalls and receiving waters (Trigg Lake and Big Bear Creek) to document the magnitude and potential effects of aircraft deicer and anti-icer fluid (ADAF) runoff on water quality. Glycol concentrations at outfalls ranged from less than 18 to 23,800 mg/L, whereas concentrations in Big Bear Creek were less because of dilution, dispersion, and degradation, ranging from less than 18 to 230 mg/L. Annual loading results indicate that 10 and 35% of what was applied to aircraft was discharged to Big Bear Creek in 2003 and 2004, respectively. Glycol that entered Trigg Lake was diluted and degraded before reaching the lake outlet. Dissolved oxygen (DO) concentrations at airport outfalls sometimes were low (<2.0 mg/L) but typical of what was measured in an urban reference stream. In comparison, the DO concentration at Trigg Lake monitoring sites was consistently greater than 5.5 mg/L during the monitoring period, probably because of the installation of aerators in the lake by DFW personnel. The DO concentration in Big Bear Creek was very similar at sites upstream and downstream of airport influence (>5.0 mg/L). Results of toxicity tests indicate that effects on Ceriodaphnia dubia, Pimephales promelas, and Selanastrum capricornutum are influenced by type IV ADAF (anti-icer), not just type I ADAF (deicer) as is more commonly assumed.
Multiphase biokinetic modeling of cadmium accumulation inDaphnia magnafrom dietary and aqueous sources
Authors: Guan Rui , Wang Wen-Xiong
Published: October 2006

We investigated the Cd accumulation dynamics in a freshwater cladoceran, Daphnia magna, and validated the biokinetic accumulation model under nonsteady-state conditions. All biokinetic parameters were monitored for the animals from birth to the adult stage. During the whole exposure period, two factors were observed to play critical roles in affecting Cd bioaccumulation. One was the Cd partitioning between the dissolved and dietary phases. Although the total Cd loads in the exposure media were kept constant, the increasing Cd partitioning from the water to the food promoted Cd bioaccumulation by approximately twofold. The other factor was the growth rate constant, which was comparable with the Cd efflux rate constant in daphnids and significantly influenced Cd accumulation because of its variation in different developmental stages. A multiphase modeling approach was used to simulate such a nonsteady-state process. This approach was viewed as a success, because the model simulations clearly aided in the interpretation of the experimentally observed temporal Cd accumulation in daphnids. Proper application of the kinetic bioaccumulation model undoubtedly will help us to understand time-dependent responses under the nonsteady state, which may be caused by episodic exposure or seasonal fluctuations in food/particle availability.
Metallodielectric Hollow Shells: Optical and Catalytic Properties
Authors: Pastoriza‐Santos Isabel , Pérez‐Juste Jorge , Carregal‐Romero Susana , Hervés Pablo , Liz‐Marzán Luis M.
Published: October 2006

Metallodielectric composites with tunable optical properties were prepared by layer‐by‐layer assembly of gold nanorods on polystyrene (PS) spheres and subsequent deposition of SiO2 or TiO2 encapsulating shells through a sol–gel process. The optical properties of the core‐shells were tailored in the visible and the near‐infrared region through the gold nanorod aspect ratio and the gold nanoparticle density. Removal of the PS core by dissolution in an appropriate solvent, such as THF, yielded metallodielectric hollow shells with optical properties identical to those of the original composites. The presence of gold and the porosity of the SiO2 or TiO2 shells, suitable to allow diffusion of reactants and products, make these materials of interest as catalysts, as demonstrated by the reduction of potassium hexacyanoferrate(III) with NaBH4.
Biogas plasticization coupled anaerobic digestion: Batch test results
Authors: Schimel Keith A.
Published: October 2006

Biogas has unique properties for improving the biodegradability of biomass solids during anaerobic digestion (AD). This report presents batch test results of the first investigation into utilizing biogas plasticization to “condition” organic polymers during active digestion of waste activated sludge (WAS). Preliminary design calculations based on polymer diffusion rate limitation are presented. Analysis of the 20°C batch test data determined the first order (k1) COD conversion coefficient to be 0.167 day−1 with a maximum COD utilization rate of 11.25 g L−1 day−1. Comparison of these batch test results to typical conventional AD performance parameters showed orders of magnitude improvement. These results show that biogas plasticization during active AD could greatly improve renewable energy yields from biomass waste materials such as MSW RDF, STP sludges, food wastes, animal manure, green wastes, and agricultural crop residuals. Biotechnol. Bioeng. 2007;97: 297–307. © 2006 Wiley Periodicals, Inc.
A gas‐inducible expression system in HEK.EBNA cells applied to controlled proliferation studies by expression of p27Kip1
Authors: Werner Nicola Susann , Weber Wilfried , Fussenegger Martin , Geisse Sabine
Published: October 2006

We describe an efficient inducible gene expression system in HEK.EBNA cells, a well‐established cell system for the rapid transient expression of research‐tool proteins. The transgene control system of choice is the novel acetaldehyde‐inducible regulation (AIR) technology, which has been shown to modulate transgene levels following exposure of cells to acetaldehyde. For application in HEK.EBNA cells, AlcR transactivator plasmids were constructed and co‐expressed with the secreted alkaline phosphatase (SEAP) gene under the control of a chimeric mammalian promoter (PAIR) for acetaldehyde‐regulated expression. Several highly inducible transactivator cell lines were established. Adjustable transgene induction by gaseous acetaldehyde led to high induction levels and tight repression in transient expression trials and in stably transfected HEK.EBNA cell lines. Thus, the AIR technology can be used for inducible expression of any desired recombinant protein in HEK.EBNA cells. A possible application for inducible gene expression is a controlled proliferation strategy. Clonal HEK.EBNA cell lines, expressing the fungal transactivator protein AlcR, were engineered for gas‐adjustable expression of the cell‐cycle regulator p27Kip1. We show that expression of p27Kip1 via transient or stable transfection led to a G1‐phase specific growth arrest of HEK.EBNA cells. Furthermore, production pools engineered for gas‐adjustable expression of p27Kip1 and constitutive expression of SEAP showed enhanced productive capacity. Biotechnol. Bioeng. 2007;96:1155–1166. © 2006 Wiley Periodicals, Inc.
Investigation of metabolic objectives in cultured hepatocytes
Authors: Uygun Korkut , Matthew Howard W.T. , Huang Yinlun
Published: October 2006

Using optimization based methods to predict fluxes in metabolic flux balance models has been a successful approach for some microorganisms, enabling construction of in silico models and even inference of some regulatory motifs. However, this success has not been translated to mammalian cells. The lack of knowledge about metabolic objectives in mammalian cells is a major obstacle that prevents utilization of various metabolic engineering tools and methods for tissue engineering and biomedical purposes. In this work, we investigate and identify possible metabolic objectives for hepatocytes cultured in vitro. To achieve this goal, we present a special data‐mining procedure for identifying metabolic objective functions in mammalian cells. This multi‐level optimization based algorithm enables identifying the major fluxes in the metabolic objective from MFA data in the absence of information about critical active constraints of the system. Further, once the objective is determined, active flux constraints can also be identified and analyzed. This information can be potentially used in a predictive manner to improve cell culture results or clinical metabolic outcomes. As a result of the application of this method, it was found that in vitro cultured hepatocytes maximize oxygen uptake, coupling of urea and TCA cycles, and synthesis of serine and urea. Selection of these fluxes as the metabolic objective enables accurate prediction of the flux distribution in the system given a limited amount of flux data; thus presenting a workable in silico model for cultured hepatocytes. It is observed that an overall homeostasis picture is also emergent in the findings. Biotechnol. Bioeng. 2007;97: 622–637. © 2006 Wiley Periodicals, Inc.
Late adverse effects of short-course preoperative radiotherapy in rectal cancer
Authors: Pollack J , Holm T , Cedermark B , Altman D , Holmström B , Glimelius B , Mellgren A
Published: October 2006

Background

Preoperative radiotherapy improves local control and survival in rectal cancer, but there are few reports on long-term morbidity. The aims of this study were to compare long-term morbidity and quality of life in patients undergoing rectal cancer surgery with or without preoperative radiotherapy.

Methods

A total of 252 patients, randomized within the two Stockholm trials on preoperative radiotherapy in rectal cancer, were alive at a mean of 15 years after surgery. Some 139 of these patients were available for follow-up by questionnaires and clinical examination. Questionnaires regarding medical history and quality of life were completed by all patients. All patients had a clinical examination, and those without a stoma underwent rigid sigmoidoscopy.

Results

Overall, patients who had preoperative radiotherapy experienced significantly more late complications than those who did not (69 versus 43 per cent; P = 0·002). This morbidity consisted mainly of cardiovascular disease (35 versus 19 per cent; P = 0·032), faecal incontinence (12 of 21 versus 11 of 42 patients having anterior resection; P = 0·013) and urinary incontinence (45 versus 27 per cent; P = 0·023). No significant differences between groups were found for hip or pelvic fractures, small bowel obstruction or global quality of life.

Conclusion

Preoperative short-course, high-dose radiotherapy in patients with rectal cancer increases the risk of anal and urinary dysfunction, and may lead to increased cardiovascular morbidity, at long-term follow-up.
Characterization of reflux events after fundoplication using combined impedance–pH recording
Authors: Roman S , Poncet G , Serraj I , Zerbib F , Boulez J , Mion F
Published: October 2006

Background

Laparoscopic fundoplication effectively controls symptoms of gastro-oesophageal reflux disease (GORD) and decreases acid reflux, but its impact on non-acid reflux is not known. The aim of the study was to characterize reflux events after fundoplication using oesophageal combined multichannel intraluminal impedance (MII)–pH monitoring, to demonstrate its efficacy on acid as well as non-acid reflux events.

Methods

Thirty-six patients in whom ambulatory MII–pH recording was performed after laparoscopic fundoplication were reviewed retrospectively. There were 23 symptomatic and 13 asymptomatic patients, whose results were compared with those of 72 healthy volunteers.

Results

Oesophageal acid exposure was low in all but one operated patient, and there was no difference between those with and without symptoms. The median number of reflux events over 24 h was lower after fundoplication (11 in operated patients compared with 44 in healthy volunteers; P < 0·001). Almost all reflux events were non-acid after surgery whereas acid reflux episodes were predominant in healthy volunteers. Proximal reflux events were less common in operated patients. Non-acid reflux events were significantly associated with symptoms after surgery in some patients.

Conclusion

Fundoplication restores a competent barrier for all types of reflux. Reflux events are mostly non-acid after surgery, and such events may be positively correlated with symptoms.
Tissue oxygen saturation, measured by near-infrared spectroscopy, and its relationship to surgical-site infections
Authors: Ives C L , Harrison D K , Stansby G S
Published: October 2006

Background

Surgical-site infections (SSIs) are common after major abdominal and groin bypass surgery. Tissue oxygen tension has been shown to predict these infections accurately. This study assessed whether a non-invasive measurement of tissue oxygenation, tissue oxygen saturation as measured by spectrophotometry, was as accurate.

Methods

Fifty-nine patients having major abdominal or groin bypass surgery had tissue oxygen saturation measured by near-infrared spectrophotometry at the incision site and in the arm before operation, and at 12, 24 and 48 h after surgery. Masked outcome assessments for SSI were made at 7 and 30 days after operation.

Results

In this retrospective analysis, 17 patients (29 per cent) developed an SSI. At 12 h after operation there was a significant difference in tissue oxygen saturation at the surgical site between patients who developed an SSI and those who did not (mean(s.d.) 43·4(18·1) versus 55·8(22·0) per cent; P = 0·032). These oxygen saturation readings were found to be more specific and sensitive in predicting SSIs than the National Nosocomial Infection Surveillance system.

Discussion

There is a difference in postoperative surgical-site oxygen saturation between patients who subsequently develop SSIs and those who do not. Prediction of SSIs provides opportunities for intervention and prevention.
Cancer of the gastric stump following distal gastrectomy for cancer
Authors: Ohashi M , Katai H , Fukagawa T , Gotoda T , Sano T , Sasako M
Published: October 2006

Background

Cancer of the gastric stump (CGS) after distal gastrectomy for cancer has not been characterized in a large study. The aim of this study was to investigate the clinicopathological features and outcome of CGS following distal gastrectomy for cancer.

Methods

Patients with CGS following distal gastrectomy for gastric cancer diagnosed between 1970 and 2002 were reviewed retrospectively.

Results

A total of 108 patients was identified. The median interval between the initial gastrectomy and resection for CGS was 7·5 (range 1–41) years. The depth of tumour invasion was T1 in 67 patients, T2 in 16, T3 in eight and T4 in 17 patients. Endoscopic mucosal resection was performed in 25 patients with T1 tumours. R0 resection was achieved in 103 patients. The overall 5-year survival rate was 53·1 per cent. The 5-year survival rates for patients with T1, T2, T3 and T4 disease were 76, 40, 13 and 9 per cent respectively.

Conclusion

The outcome for patients with non-early CGS was poor. Early detection of CGS is important following distal gastrectomy for gastric cancer and strict surveillance is recommended for at least 10 years after the initial gastrectomy.
Negative stress-coping strategies among novices in surgery correlate with poor virtual laparoscopic performance
Authors: Hassan I , Weyers P , Maschuw K , Dick B , Gerdes B , Rothmund M , Zielke A
Published: October 2006

Background

This study explored the impact of habitual stress-coping strategies on the laparoscopic performance of novices in surgery using a virtual reality simulator.

Methods

The SVF78 stress-coping questionnaire was administered to 12 medical students in their final year of medical school (camera holders) and to 12 inexperienced surgical residents (postgraduate years 1–3). The questionnaire included devaluation during stressful situations, distractions from stressful situations, control over stressful reactions and negative coping strategies such as stress avoidance and need for social support. Assessment of laparoscopic dexterity was based on the results of performance on a virtual reality simulator. The variables of time taken to complete the task, errors and economy of motion were analysed, with a higher score indicating poor performance. Pearson and non-parametric Spearman correlations were used to compare the subjects' results on the SVF78 with those on the LapSim®.

Results

Time taken to complete the task correlated with high values in distractive stress-coping strategies (P = 0·002) and high values in negative stress-coping strategies (P = 0·042).

Conclusion

Ineffective stress-coping strategies correlate with poor virtual laparoscopic performance. The need for effective intraoperative stress-coping strategies is evident.
Laparoscopy as a routine approach for left lateral sectionectomy
Authors: Chang S , Laurent A , Tayar C , Karoui M , Cherqui D
Published: October 2006

Background

Since 1997, the authors have performed laparoscopic left lateral sectionectomy of lesions of the liver in preference to open surgery. The aim of this study was to assess the outcome.

Methods

Between October 1997 and March 2005, 36 laparoscopic left lateral sectionectomies were performed using five trocars and a small incision for specimen retrieval. Liver resection was performed mainly using a harmonic scalpel and staplers. The Pringle manoeuvre was used in 24 patients.

Results

The mean patient age was 55·2 (range 31–80) years. Twelve patients had underlying cirrhosis. Surgery was performed for 20 malignant lesions and 16 benign lesions with a mean size of 42·7 (range 5–110) mm. Conversion to laparotomy occurred in one patient. The mean operating time was 171·5 (range 90–240) min. Operatiing time and use of the Pringle manoeuvre were significantly decreased in the second half of the series. Mean blood loss was 208 (range 50–600) ml. No transfusion was required. There were no deaths. Two patients had postoperative complications (one incisional hernia and one pneumonia). The median postoperative stay was 5·2 days.

Conclusion

The laparoscopic approach to left lateral sectionectomy was safe and feasible in this series and could be considered as a routine approach in selected patients.
The metamerism potentiality of a color recipe
Authors: Peyvandi Shahram , Hossein Amirshahi Seyed
Published: October 2006

The weighted spectrophotometric color matching method with the optimum weighting to the spectrophotometric equations in each particular wavelength proportional to the viewing condition is applied for minimizing the color difference of instrumental color formulation of textile materials. The work is based on the one‐constant Kubelka–Munk theory. The sensitivity of a recipe to small perturbation of deviation between the reflectance of target and matched samples in the visible spectrum is determined as the metamerism potentiality of proposed recipe. Its correlation with metamerism index was also studied for some metameric pairs. Metamerism potentialities are also appraised under several light sources by using equilibrate matching strategy. The results show that the outputs of colorimetric color matching are exactly identical with the weighted spectrophotometic match under the same viewing condition. According to the numerical results for matching of 58 target samples, there is a good statistical correlation between metamerism indices and the metamerism potentialities of each recipe. Our results show that the quantitative value of the metamerism potentiality of each recipe can reasonably predict the metamerism indices of applied formulation. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 483–490, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20261
Reflection of light from semi‐infinite absorbing turbid media. Part 1: Spherical albedo
Authors: Kokhanovsky Alexander A. , Sokoletsky Leonid G.
Published: October 2006

The purpose of this article is to study the accuracy of a number of simple approximate equations for the spherical albedo r (or the hemispherical reflectance under diffuse illumination conditions) of semi‐infinite light scattering absorbing media, using numerical solutions of the nonlinear integral equation for the reflection function of a semi‐infinite turbid medium, as formulated by V. A. Ambartsumian. We find that the van de Hulst approximation provides the most accurate approximation for the diffuse reflectance r under diffuse illumination conditions. The value of r depends almost exclusively on the value of the similarity parameter $s=\sqrt{(1-{\omega}_{0})(1-g{\omega}_{0})^{-1}}$, where ω0 is the single scattering albedo and g is the asymmetry parameter.

A simple approach to derive the normalized absorption spectra of particulate matter from reflectance measurements is proposed. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 491–497, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20262
The half-life of hepatitis B virions
Authors: Murray John M. , Purcell Robert H. , Wieland Stefan F.
Published: October 2006

The virion half-life of hepatitis B virus (HBV) is currently estimated at approximately 1 day. This estimate has been obtained from drug perturbation experiments with reverse transcriptase inhibitors. However, the analyses of those experiments have not considered the export of virions produced from preformed mature DNA-containing HBV capsids in infected cells. Data from 3 acutely infected chimpanzees indicates that there is approximately 10-fold more total intracellular HBV DNA than HBV DNA in blood, and therefore the half-life of virions for chimpanzees during acute infection is 10-fold shorter at 3.8 hours than the half-life associated with export of total intracellular HBV DNA. Mathematical model simulations duplicating the viral dynamics observed in drug perturbation experiments suggest a half-life of at most 4.4 hours for HBV virions in chronically infected humans, significantly shorter than current estimates, but consistent with the half-lives of virions for hepatitis C virus and HIV. This faster turnover of HBV in blood indicates a correspondingly higher replication rate and risk of mutation against hepatitis B antiviral therapy.

In conclusion

, we find the half-life of HBV virions is approximately 4 hours, significantly shorter than current estimates of 1 day. This new value is consistent with virion half-life estimates for HIV and hepatitis C virus.
Cellular and humoral autoimmunity directed at bile duct epithelia in murine biliary atresia
Authors: Mack Cara L. , Tucker Rebecca M. , Lu Brandy R. , Sokol Ronald J. , Fontenot Andrew P. , Ueno Yoshiyuki , Gill Ronald G.
Published: October 2006

Biliary atresia is an inflammatory fibrosclerosing lesion of the bile ducts that leads to biliary cirrhosis and is the most frequent indication for liver transplantation in children. The pathogenesis of biliary atresia is not known; one theory is that of a virus-induced, subsequent autoimmune-mediated injury of bile ducts. The aim of this study was to determine whether autoreactive T cells and autoantibodies specific to bile duct epithelia are present in the rotavirus (RRV)- induced murine model of biliary atresia and whether the T cells are sufficient to result in bile duct inflammation.

In vitro

analyses showed significant increases in IFN-γ–producing T cells from RRV-diseased mice in response to bile duct epithelial autoantigen. Adoptive transfer of the T cells from RRV-diseased mice into naïve syngeneic SCID recipients resulted in bile duct–specific inflammation. This induction of bile duct pathology occurred in the absence of detectable virus, indicating a definite response to bile duct autoantigens. Furthermore, periductal immunoglobulin deposits and serum antibodies reactive to bile duct epithelial protein were detected in RRV-diseased mice.

In conclusion,

both cellular and humoral components of autoimmunity exist in murine biliary atresia, and the progressive bile duct injury is due in part to a bile duct epithelia–specific T cell–mediated immune response. The role of cellular and humoral autoimmunity in human biliary atresia and possible interventional strategies therefore should be the focus of future research.
Protection against Western diet–induced obesity and hepatic steatosis in liver fatty acid–binding protein knockout mice
Authors: Newberry Elizabeth P. , Xie Yan , Kennedy Susan M. , Luo Jianyang , Davidson Nicholas O.
Published: October 2006

Liver fatty acid–binding protein (L-Fabp) regulates murine hepatic fatty acid trafficking in response to fasting. In this study, we show that L-Fabp−/− mice fed a high-fat Western diet for up to 18 weeks are less obese and accumulate less hepatic triglyceride than C57BL/6J controls. Paradoxically, both control and L-Fabp−/− mice manifested comparable glucose intolerance and insulin resistance when fed a Western diet. Protection against obesity in Western diet–fed L-Fabp−/− mice was not due to discernable changes in food intake, fat malabsorption, or heat production, although intestinal lipid secretion kinetics were significantly slower in both chow-fed and Western diet–fed L-Fabp−/− mice. By contrast, there was a significant increase in the respiratory exchange ratio in L-Fabp−/− mice, suggesting a shift in energy substrate use from fat to carbohydrate, findings supported by an approximately threefold increase in serum lactate. Microarray analysis revealed increased expression of genes involved in lipid synthesis (fatty acid synthase, squalene epoxidase, hydroxy-methylglutaryl coenzyme A reductase), while genes involved in glycolysis (glucokinase and glycerol kinase) were decreased in L-Fabp−/− mice. Fatty acid synthase expression was also increased in the skeletal muscle of L-Fabp−/− mice.

In conclusion

, L-Fabp may function as a metabolic sensor in regulating lipid homeostasis. We suggest that L-Fabp−/− mice are protected against Western diet–induced obesity and hepatic steatosis through a series of adaptations in both hepatic and extrahepatic energy substrate use.

Supplementary material for this article can be found on the HEPATOLOGY website
(http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).
Sustained activation of Rac1 in hepatic stellate cells promotes liver injury and fibrosis in mice
Authors: Choi Steve S. , Sicklick Jason K. , Ma Qi , Yang Liu , Huang Jiawen , Qi Yi , Chen Wei , Li Yin-Xiong , Goldschmidt-Clermont Pascal J. , Diehl Anna Mae
Published: October 2006

Rac, a small, GTP-binding protein in the Rho family, regulates several cellular functions, including the activation of NADPH oxidase, a major intracellular producer of reactive oxygen species (ROS). Hepatic stellate cells (HSCs) isolated from mice that are genetically deficient in NADPH oxidase produce less ROS, and their activation during chronic liver injury is abrogated, resulting in decreased liver fibrosis. Therefore, we hypothesized that HSC ROS production and activation would be enhanced, and fibrosis worsened, by increasing Rac expression in HSCs. To achieve this, we used transgenic mice that express constitutively active human

Rac1

under the control of the α-smooth muscle actin (α

-sma

) promoter, because α

-sma

expression is induced spontaneously during HSC activation. Transgene expression was upregulated progressively during culture of primary Rac-transgenic HSCs, and this increased HSC ROS production as well as expression of activation markers and collagen. Similarly, Rac mice treated with carbon tetrachloride (CCl4) accumulated greater numbers of activated HSCs and had more liver damage, hepatocyte apoptosis, and liver fibrosis—as well as higher mortality—than CCl4-treated wild-type mice.

In conclusion

, sustained activation of Rac in HSCs perpetuates their activation and exacerbates toxin-induced liver injury and fibrosis, prompting speculation that Rac may be a therapeutic target in patients with cirrhosis.
Sphingosine 1-phosphate protects rat liver sinusoidal endothelial cells from ethanol-induced apoptosis: Role of intracellular calcium and nitric oxide
Authors: Zheng Dong-Mei , Kitamura Tsuneo , Ikejima Kenichi , Enomoto Nobuyuki , Yamashina Shunhei , Suzuki Satoko , Takei Yoshiyuki , Sato Nobuhiro
Published: October 2006

In alcoholic liver disease, ethanol-induced damage to sinusoidal endothelial cells (SECs) appears to be important in the progression of liver damage. However, little is known about the mechanisms responsible for protection of SECs against ethanol-induced injury. To elucidate the role of sphingosine 1-phosphate (S1P), which is stored in platelets and may be released from them on their activation, we investigated the effect of S1P on rat liver SECs in primary culture. Pretreatment of cells with 1 μmol/L S1P attenuated ethanol-induced apoptosis. Electron microscopy confirmed this protective effect of S1P on damaged SECs in liver tissues after perfusion of ethanol. In the absence of ethanol, S1P increased DNA synthesis as determined via incorporation of bromodeoxyuridine. S1P also ameliorated the decreased DNA synthesis of cells induced by ethanol. Addition of S1P to cells induced an increase in intracellular calcium concentrations and NO production in cells. Western blotting revealed that S1P significantly induced the activation of endothelial NO synthase (eNOS), but not Akt, and that S1P-induced activation of eNOS was blocked by trifluoperazine, a calmodulin inhibitor. Furthermore,

N

G-nitro-L-arginine methyl ester, a NO synthase inhibitor, cancelled the effect of S1P on DNA synthesis, apoptosis, and NO production

in vitro

as well as the protective effect of S1P on cell damage

in situ

.

In conclusion

, the biological effect of S1P is at least partially mediated by Ca2+-sensitive eNOS activation and subsequent NO formation; extracellular S1P could contribute to sinusoidal protection and remodeling in alcoholic liver injury.

Supplementary material for this article can be found on the HEPATOLOGY website
(http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).
Beyond randomized controlled trials: A critical comparison of trials with nonrandomized studies
Authors: Sφrensen Henrik Toft , Lash Timothy L. , Rothman Kenneth J.
Published: October 2006

Observational analogs of randomized clinical trials (RCTs) are well accepted in the study of disease risk factors, diagnosis, and prognosis. There is controversy about observational studies when the focus is on the intended benefit due to lack of blinding and poor control for unmeasured confounding. Well-designed randomized clinical trials are costly both in time and money. Therefore, existing databases are used increasingly and are often the only feasible source with which to examine delayed health effects. We reviewed the reasons for possible discrepancies between RCTs and observational studies. There can be different patient populations, differences in therapeutic regimen, control of confounding, follow-up, measuring outcome, and differences arising from the intention-to-treat analysis. Observational studies cannot replace trials, nor do trials make observational studies unnecessary. Both designs are susceptible to particular bias, so neither provides perfect information.
Food groups and renal cell carcinoma: A case–control study from Italy
Authors: Bravi Francesca , Bosetti Cristina , Scotti Lorenza , Talamini Renato , Montella Maurizio , Ramazzotti Valerio , Negri Eva , Franceschi Silvia , La Vecchia Carlo
Published: October 2006

Although nutrition and diet have been related to renal cell carcinoma (RCC), the role of specific foods or nutrients on this cancer is still controversial. We evaluated the relation between a wide range of foods and the risk of RCC in an Italian case–control study including 767 patients (494 men and 273 women) younger than 79 years with incident, histologically confirmed RCC, and 1,534 controls (988 men and 546 women) admitted to the same hospitals as cases for a wide spectrum of acute, non‐neoplastic conditions, not related to long term diet modifications. A validated and reproducible food frequency questionnaire, including 78 foods and beverages, plus a separate section on alcohol drinking, was used to assess patients' dietary habits 2 years before diagnosis or hospital admission. Multivariate odds ratios (OR) were obtained after allowance for energy intake and other major confounding factors. A significant direct trend in risk was found for bread (OR = 1.94 for the highest versus the lowest intake quintile), and a modest excess of risk was observed for pasta and rice (OR = 1.29), and milk and yoghurt (OR = 1.27). Poultry (OR = 0.74), processed meat (OR = 0.64) and vegetables (OR = 0.65) were inversely associated with RCC risk. No relation was found for coffee and tea, soups, eggs, red meat, fish, cheese, pulses, potatoes, fruits, desserts and sugars. The results of this study provide further indications on dietary correlates of RCC, and in particular indicate that a diet rich in refined cereals and poor in vegetables may have an unfavorable role on RCC. © 2006 Wiley‐Liss, Inc.
p73 gene promoter methylation in Epstein‐Barr virus‐associated gastric carcinoma
Authors: Ushiku Tetsuo , Chong Ja‐Mun , Uozaki Hiroshi , Hino Rumi , Chang Moon‐Sung , Sudo Makoto , Rani Barua Rita , Sakuma Kazuya , Nagai Hideo , Fukayama Masashi
Published: October 2006

To clarify the significance of p73 in Epstein‐Barr virus (EBV)‐associated gastric carcinoma (GC), the immunohistochemical expression and CpG‐island methylation of p73 were evaluated in cancer tissues and adjacent nonneoplastic tissues of GC with and without EBV infection. Loss of p73 expression by immunohistochemistry was specific to EBV‐associated GC (11/13) compared to EBV‐negative GC (3/38), which was independent of abnormal p53 expression. With methylation‐specific polymerase chain reaction (MSP), the aberrant methylation of p73 exon 1 was similarly specific to EBV‐associated GC (12/13), and also rare in EBV‐negative GC (2/38). Bisulfite sequencing for p73 exon 1 and its 5′ region confirmed the MSP results, showing uniform and high‐density methylation in EBV‐associated GC. Comparative MSP analysis of p14, p16 and p73 methylation, using 20 cases each of formalin‐fixed and paraffin‐embedded tissues of early GC with and without EBV infection, confirmed 2 types of methylation: global methylation with increased rates (p14 and p16) and specific methylation of p73 in EBV‐associated GC. In nonneoplastic mucosa, p14, p16 and p73 methylation occurred in both EBV‐associated (8/33, 6/34 and 3/38, respectively) and EBV‐negative GC (6/23, 4/35, and 1/35). p73 methylation was observed in the mucosa without H. pylori infection in all 4 samples. Loss of p73 expression through aberrant methylation of the p73 promoter occurs specifically in EBV‐associated GC, together with the global methylation of p14 and p16. A specific type of gastritis, prone to a higher grade of atrophy and p73 methylation, may facilitate the development of EBV‐associated GC. © 2006 Wiley‐Liss, Inc.
Silibinin polarizes Th1/Th2 immune responses through the inhibition of immunostimulatory function of dendritic cells
Authors: Lee Jun Sik , Kim Sang Gap , Kim Hyung Keun , Lee Tae‐Hyung , Jeong Young‐Il , Lee Chang‐Min , Yoon Man‐Soo , Na Yong Jin , Suh Dong‐Soo , Park Nam Cheol , Choi In‐hak , Kim Gi‐Young , Choi Yung Hyun , Chung Hae Young , Park Yeong‐Min
Published: October 2006

Silibinin is the primary active compound in silymarin. It has been demonstrated to exert anti‐carcinogenic effects and hepato‐protective effects. However, the effects of silibinin on the maturation and immunostimulatory activities exhibited by dendritic cells (DCs) remain, for the most part, unknown. In this study, we have attempted to determine whether silibinin can influence surface molecule expression, dextran uptake, cytokine production, capacity to induce T‐cell differentiation, and the signaling pathways underlying these phenomena in murine bone marrow‐derived DCs. Silibinin was shown to significantly suppress the expression of CD80, CD86, MHC class I, and MHC class II in the DCs, and was also associated with impairments of LPS‐induced IL‐12 expression in the DCs. Silibinin‐treated DCs proved highly efficient with regard to Ag capture via mannose receptor‐mediated endocytosis. Silibinin also inhibited the LPS‐induced activation of MAPKs and the nuclear translocation of the NF‐κB p65 subunit. Additionally, silibinin‐treated DCs evidenced an impaired induction of Th1 response, and a normal cell‐mediated immune response. These findings provide new insight into the immunopharmacological functions of silibinin, especially with regard to their impact on the DCs. These findings expand our current understanding of the immunopharmacological functions of silibinin, and may prove useful in the development of therapeutic adjuvants for acute and chronic DC‐associated diseases. J. Cell. Physiol. 210: 385–397, 2007. © 2006 Wiley‐Liss, Inc.
Inter‐ and intraobserver variability in the evaluation of dynamic breast cancer MRI
Authors: Beresford Mark J. , Padhani Anwar R. , Taylor N. Jane , Ah‐See Mei‐Lin , Stirling J. James , Makris Andreas , d'Arcy James A. , Collins David J.
Published: October 2006

Purpose

To quantify variations within and between observers ascribable to manual region of interest (ROI) placement in patients with breast cancer undergoing dynamic MRI.

Materials and Methods

Expert and nonexpert observers independently outlined tumor ROIs on 30 dynamic T1‐weighted (T1W) MRI scans on five occasions over two months. Lesion size (number of pixels) and kinetic parameter estimates, including the transfer constant (Ktrans), were calculated for each ROI placement. Inter‐ and intraobserver variability was assessed with respect to the interval between drawings, lesion morphology, and observer experience.

Results

For the nonexpert, the variability reduced with decreasing time intervals between ROI drawings (the coefficient of variance (wCV) values at two months, two weeks, one day, and same‐day time intervals were respectively 11.6%, 10.7%, 4.8%, and 2.6% for lesion size, and 8.9%, 9.7%, 6.7%, and 3.2% for Ktrans). For the expert observer, the variability was smaller overall and more constant, but improved for same‐day ROI placements (region size wCV: 7.5%, 6.2%, 7.1%, and 3.7%; Ktrans wCV: 5.4%, 5.3%, 5.6%, and 4.5%).

Conclusion

Significant observer variability in manual ROI placement occurs in dynamic MRI of breast cancer. For serial patient studies, ROI placements should be outlined at the same sitting to minimize observer error. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.