bluuebunny/crossref_metadata_2025 huggingface dataset:
Topologically Chiral Covalent Assemblies of Molecular Knots with Linear, Branched, and Cyclic Architectures
Authors: Lukin Oleg , Kubota Takateru , Okamoto Yoshio , Kaufmann Astrid , Vögtle Fritz
Published: April 2004

Selectively functionalized molecular knots (knotanes) of the amide‐type have been used as building blocks in syntheses of higher covalent assemblies composed of up to four knotane units. Preparation of linear and branched tetraknotanes consisted of the consecutive selective removal of allyl groups followed by linking of the intermediate hydroxyknotanes with biphenyl‐4,4′‐disulfonyl chloride. Macrocyclic knotane oligomers involving two, three, and four knotane moieties were obtained by high‐dilution cyclization of dihydroxyknotane and biphenyl‐4,4′‐disulfonyl chloride. Due to their relation with cyclophanes, the latter class of oligomeric knotanes was termed “knotanophanes“. Chiral resolution analysis of new oligoknotanes has been attempted on chemically bonded Chiralpak AD stationary phases, however met severe difficulties due to their complex isomeric compositions, and in most cases a significant overlap of the isomer fractions was observed. In spite of the limits of presently available chiral stationary phases that allowed only partial resolution of the synthesized topologies, oligoknotanes have been shown to be of high fundamental interest due to their unprecedented chirality. The chirality descriptions of topologically chiral unsymmetrical dumbbell 4, and the linear tetraknotane 5 are analogous to the Fischer projections of erythrose/threose and hexaric acid, respectively, while the isomeric composition of the branched tetraknotane 8 is completely unique. Moreover, the linear and branched tetraknotanes are constitutional isomers. Chirality of knotanophanes represents, in turn, analogies to known cyclic forms of peptides or sugars with multiple stereogenic centers.
Peralkynylated Buta‐1,2,3‐Trienes: Exceptionally Low Rotational Barriers of Cumulenic CC Bonds in the Range of Those of Peptide CN Bonds
Authors: Auffrant Audrey , Jaun Bernhard , Jarowski Peter D. , Houk Kendall N. , Diederich François
Published: April 2004

A variety of 1,1,4,4‐tetraal kynylbutatrienes and 1,4‐dialkynylbutatrienes was synthezized by dimerization of the corresponding gem‐dibromoolefins. Both 1H and 13C NMR spectroscopy indicated that the di‐ and tetraalkynylated butatrienes are formed as a mixture of cis and trans isomers. Variable temperature NMR studies evidenced a facile cis–trans isomerization, thus preventing the separation of these isomers by gravity or high‐performance liquid chromatography (HPLC). For 1,1,4,4‐tetraalkynylbutatrienes, the activation barrier ΔG≠ was measured by magnetization transfer to be around 20 kcal mol−1, in the range of the barrier for internal rotation about a peptide bond. Unlike the tetraalkynylated [3]cumulenes, 1,4‐dialkynylbutatrienes are more difficult to isomerize and could, in one case, be obtained isomerically pure. Based on experimental data, the rotational barrier ΔG≠ for 1,4‐dialkynylbutatrienes is estimated to be around 25 kcal mol−1. The hypothesis of a stabilizing effect of the four alkynyl substituents on the proposed but‐2‐yne‐1,4‐diyl singlet diradical transition state of this cis–trans isomerization is further supported by a computational study.
The association between 3‐hydroxy‐3‐methylglutaryl conenzyme A inhibitor use and breast carcinoma risk among postmenopausal women
Authors: Boudreau Denise M. , Gardner Jacqueline S. , Malone Kathleen E. , Heckbert Susan R. , Blough David K. , Daling Janet R.
Published: April 2004

BACKGROUND

Statin use has increased dramatically in the U.S. in the past decade. Animal and mechanistic studies suggested that statins may have an inhibitory effect on cancer proliferation, including breast carcinoma. However, statins have been found to be carcinogenic in rodents and one clinical trial found an excess of breast carcinoma cases in the treatment group.

METHODS

The current study assessed whether the use of statins altered the risk of breast carcinoma in older women. The population‐based, case–control study comprised female residents from three western Washington State counties. Cases included 975 women identified from the Cancer Surveillance System who were diagnosed with primary invasive breast carcinoma between 1997–1999, whose names appeared on a list of Social Security recipients provided by the Centers for Medicare and Medicaid Services. The cases were ages 65–79 years at the time of diagnosis. The comparison group was comprised of 1007 women without breast carcinoma who were randomly selected from the same list of Social Security recipients. Information pertaining to statin use, medical history, and health behaviors was ascertained through an in‐person interview.

RESULTS

Compared with nonusers, women who were currently using statins or had ever used statins were not found to be at an increased risk for breast carcinoma (odds ratios [OR] = 0.9; 95% confidence interval [95% CI], 0.7–1.2). There was some indication that long‐term statin use (> 5 years) was related to a slight decrease in breast carcinoma risk (OR = 0.7; 95% CI, 0.4–1.0).

CONCLUSIONS

The results of the current study provided some degree of reassurance to the increasing numbers of women using statins that such use is not associated with an increased risk of breast carcinoma. Although the data gave some support to a reduced risk of breast carcinoma among long‐term users of statins, further research is needed to confirm this association. Cancer 2004. © 2004 American Cancer Society.
A non‐linear triangular curved shell element
Authors: Wenzel T. , Schoop H.
Published: April 2004

The objective of this paper is to present and test a simple triangular finite shell element that uses five degrees of freedom at each node. The element is characterized by three position vectors and three unit directors. It depicts the plane stress state version of the element presented (Comput. Struct. 1989; 32(2):379). The element is of the ANS‐type (assumed natural strain (J. Appl. Mech. 1981; 48:587). All strains inside the element contain dot products of the six actual element nodal vectors. The construction of the element also allows non‐linear material behaviour. Since an enhancement of the membrane strains by the EAS (enhanced assumed strain method) is not possible inside a three node triangle element, the membrane strains perform poor. But via the DKT (discrete Kirchhoff theory) the three directors reveal an excellent bending behaviour for thin shells. The main concern of this paper is to test, if superimposing the CST (constant srain) with the classic DKT leads to good results in standard benchmark tests. Copyright © 2004 John Wiley & Sons, Ltd.
Local error estimation for dimensional reduction: application to special geometries
Authors: Vemaganti Kumar , Billade Nilesh
Published: April 2004

Dimensional reduction is commonly used to simplify problems posed on thin three‐dimensional domains to more manageable two‐dimensional problems. The resulting modelling error is usually assumed to be negligible. Recently, an approach has emerged wherein the modelling error in dimensionally reduced models of elliptic boundary value problems posed on thin flat plates is locally estimated using duality arguments. We extend this approach to elliptic boundary value problems posed on thin circular arches and spherical shells. Preliminary numerical examples show that bounds are accurate even for thick arches and shells. Copyright © 2004 John Wiley & Sons, Ltd.
Fluorescence resonance energy transfer (FRET)‐based specific labeling ofCryptosporidiumoocysts for detection in environmental samples
Authors: Chung J. , Vesey G. , Gauci M. , Ashbolt N.J.
Published: April 2004

Background

Accurate detection and quantification ofCryptosporidiumoocysts in water are a challenge to the water industry. This article demonstrates a way to fluorescently labelCryptosporidiumoocysts, based on fluorescence resonance energy transfer (FRET). Labeled oocysts can then be applied to environmental waters and their movement followed by flow cytometric detection and enumeration of the FRET‐labeled oocysts, as demonstrated here with environmental water samples.

Methods

Cryptosporidiumoocysts were labeled with three fluorochromes, FITC, Texas red, and Cy7, that through FRET yielded a Stokes shift of ∼272 nm with excitation from a standard argon laser emitting at 488 nm. Defined flow cytometric settings and gatings were used to select FITC/green (530‐nm), Texas red/red (650‐nm), and Cy7/infrared (780‐nm) fluorescing particles with light scatter properties similar to oocysts. Water concentrates were seeded with 10 tri‐labeled oocysts and were analyzed using flow cytometry. Unseeded water concentrates were also analyzed.

Results

Analysis of unseeded water concentrates detected no autofluorescent particle similar to the labeled oocysts. Labeled oocysts were detected successfully with up to 85% recovery in water concentrates spiked with 10 tri‐labeled oocysts.

Conclusions

Low numbers of FRET‐labeled oocysts can be quantified and clearly distinguished from autofluorescing background in environmental water concentrates. © 2004 Wiley‐Liss, Inc.
Oral spray insulin in treatment of type 2 diabetes: a comparison of efficacy of the oral spray insulin (Oralin) with subcutaneous (SC) insulin injection, a proof of concept study
Authors: Guevara‐Aguirre Jaime , Guevara Marco , Saavedra Jeannette , Mihic Marko , Modi Pankaj
Published: April 2004

Objective

Proof‐of‐concept study of evaluation of metabolic effect of novel oral spray insulin (Oralin) formulation at breakfast time in subjects with type 2 diabetes on multiple daily injections.

Research design and methods

This was an open‐label, crossover, randomized study in (n = 23) subjects with type 2 diabetes on multiple daily injections. Subjects received each treatment, in random order, 3 to 7 days apart—a daily dose of SC injection (0.1 u/kg) on one occasion and Oralin spray (100 u) at time 0 min on another occasion. Subjects were given a standard breakfast containing 360 cal (Sustacal liquid meal) 10 min after the dose. Blood samples were taken at regular intervals to measure glucose, insulin, and C‐peptide.

Results

The 30‐ and 60‐min postprandial glucose levels were significantly lowered with Oralin versus that with the injection treatment (146 ± 5 mg/dL Oralin vs 184 ± 7 mg/dL injection at 30 min and 192 ± 6 mg/dL Oralin vs 236 ± 9 mg/dL injection, p < 0.003 at 60 min). The rise in serum insulin levels was significantly higher (Cmax = 98 ± 6 uU/mL for Oralin at 30 min vs 65 ± 3 uU/ml injection, p < 0.001). The reduction in C‐peptide was greater in Oralin during the first 60 min (1.38 ± 0.21 ng/mL Oralin vs 1.75 ± 0.38 ng/mL injection, p < 0.001).

Conclusions

This proof‐of‐concept study results demonstrated that Oralin could be used as meal insulin in place of mealtime‐insulin injections in subjects with type 2 diabetes to regulate the postprandial glucose levels. Copyright © 2004 John Wiley & Sons, Ltd.
Performance improvement of disk array subsystems having shared cache and control memories
Authors: Takahashi Naoya , Kurosu Yasuo
Published: April 2004

Amid trends toward the unification of storage in information systems and improvements in their operating efficiency, increased speed and greater numbers of channels for host connections are needed in disk arrays. In this paper, the authors focus on the fact that for increasing speed the network structure is more useful than the bus structure in terms of an approach for several microprocessors which comprise a disk array and the memory connections shared with them. The authors then propose a hybrid star network configuration which uses a hierarchical star network with connections over switches to cache memory where data from the host is stored temporarily, and a star network with direct connections with control memory where control tables for cache memory and other types of control information are stored. The authors create a disk array with a 32‐channel host interface using their approach, and then implement a performance evaluation. The results show that sequential performance of 920 MB per second and transaction performance of 160 kIO per second are achieved. This is equivalent to a 5‐fold increase for the former and a 2.5‐fold increase for the latter compared to a disk array using a conventional bus setup. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(10): 1–14, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20103
A method for obtaining a foot region from time‐sequential images of foot pressure for gait guidance
Authors: Shimada Satoshi , Ohtsuka Sakuichi , Tomono Akira , Arai Masanobu
Published: April 2004

A method to analyze gait based on the foot pressure distribution for several steps performed in a natural state would be useful for analyzing gait attributes and walking motion. Extracting each foot region from the foot pressure distribution is a problem in this situation. In this paper, the authors propose a method to measure the position of the foot region by focusing on distinguishing between when the center path of the foot pressure distribution when walking approximates a sine wave or follows a straight line with respect to the walking direction, and to automatically extract the foot region based on grouping the regions around the estimated positions. Based on the results of evaluation experiments, fast, accurate extractions were confirmed for various gait patterns used when analyzing gaits in rehabilitation therapy. The extraction rate was 100% for natural gait in healthy people, and about 98% overall for people with gait impairment. This rate required roughly 1 second of processing. In addition, for gait with shoes, the extraction rate was 100% for natural gait, and 90% when subjects were walking irregularly. This shows that the authors' method can also be applied to the field of crowd dynamics if one person is walking alone, as when giving gait guidance to a healthy person. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(10): 15–26, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20104
Secure implementation method of POP before SMTP using a relay server with SSL protocol
Authors: Masui Kenji , Tomoishi Masahiko , Yonezaki Naoki
Published: April 2004

POP before SMTP is a method of e‐mail authentication in which users are authenticated by POP prior to SMTP connection. This method has been recognized by RFC2476, and is being increasingly employed. However, the danger of external attack is high if the POP server is operated in a demilitarized zone. In the implementation proposed in this study, POP server is protected by a firewall; for this purpose, POP connections to the gateway are relayed to an internal POP server, while the SMTP server remains in a demilitarized zone. In addition, security is improved by applying SSL to POP sessions between the relay server and clients. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(10): 27–34, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20105
Extraction of human face and transformable region by facial expression based on extended labeled graph matching
Authors: Murakami Makoto , Yoneyama Masahide , Shirai Katsuhiko
Published: April 2004

This paper considers the recognition of moving images and proposes a new framework in which the local features, the global structure, and motion information are handled comprehensively. The method is applied to the extraction of facial expressions and its effectiveness is demonstrated. In most conventional moving image recognition methods, recognition is performed on the basis of the sequence of recognition results for individual frames. However, the authors believe that the motion information should be more positively utilized in the recognition of the individual frames. When the time‐series data are combined into the recognition of a still image, however, the amount of information is tremendous, making the processing complicated. The method proposed in this paper extends the concept of the labeled graph matching method, which has been used for still images, to moving images. The proposed method handles sparse graphs and can prevent an increase in the amount of computation. By dynamically adjusting the features to be handled according to the stage of processing, complex processing in dynamic image recognition can be integrated in a simple and straightforward way. As practical examples, the human head, and parts of the head, are extracted, indicating the effectiveness of the proposed method. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(10): 35–43, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20106
A neural network model of hippocampus‐based ganglia for rat navigation tasks
Authors: Ito Makoto , Miyake Shogo , Sawada Yasuji
Published: April 2004

It is known that rats with hippocampal lesions exhibit abnormal spatial navigation behavior. In order to analyze the role of the hippocampus of the rat in performing spatial navigation tasks, this paper presents a hippocampus–basal ganglia model. The hippocampus in this model integrates multiple visual information inputs from the visual association area, and the basal ganglia perform reinforcement learning in order to acquire a stochastic mapping from the information obtained from the visual association area and the hippocampus to the output action. Assuming milk maze tasks with visible and invisible platforms, numerical simulations are performed using the proposed model. The result is that both normal rats and rats with hippocampal lesions can perform the milk maze task with a visible platform. In the milk maze task with an invisible platform, on the other hand, rats with hippocampal lesions require a longer time than normal rats to arrive at the platform. These results agree with the experimental results. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(10): 66–80, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20109
Preparation and Structural Characterization of [K(18‐crown‐6)]+ Salts of [RNSN]− Anions and the [NSN]2− Dianion
Authors: Borrmann Tobias , Lork Enno , Mews Rüdiger , Shakirov Makhmut M. , Zibarev Andrey V.
Published: April 2004

[K(18‐crown‐6)]+ salts of the [RNSN]− anions (R = Alk, Ar) and the [NSN]2− dianion, which are thermally stable and very soluble in aprotic organic solvents, were prepared from [K(18‐crown‐6)]+[tBuO]− and the corresponding R−N=S=N−SiMe3 and (Me3Si−N=)2S, respectively. The salts are characterized by multinuclear (1H, 13C, 14N, 19F, 29Si and 39K) NMR spectroscopy in solution and by X‐ray diffraction in the solid state. The experimentally determined bond lengths confirm that the [RNSN]− anions are thiazylamides, R−N−−S≡N rather than sulfur diimides, R−N=S=N−. Relative to O=S=O, in the [NSN]2− dianion, which is the genuine aza‐analogue of sulfur dioxide, the bond lengths are elongated and the bond angle is widened. This might reflect electrostatic repulsion between the negatively charged N atoms. The experimental results are in agreement with theoretical calculations (RHF, B3LYP, MP2). In the nitrogen NMR spectra, when going from [AlkNSN]− to [ArNSN]−, the low‐field signal of the terminal (unsubstituted) N atom reveals further deshielding, whereas the high‐field signal of the internal (substituted) N atom displays further shielding. The 14N NMR resonance for the [NSN]2− dianion is practically insensitive to the counterion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
New approach to association testing in case‐parent designs under informative parental missingness
Authors: Chen Yi‐Hau
Published: April 2004

The transmission/disequilibrium test (TDT) and related methods using genotype data on diseased probands and their both parents (triads) have been popular for testing linkage or association between a disease and a candidate gene. The usefulness of the TDT‐type approaches lies mainly in their robustness, in the sense that they are valid under population stratification, arbitrary parental genotype distribution, and “informative” parental missingness where the parental missingness may depend on parental genotypes. Recently, a variety of extended TDTs were developed to accommodate parental missingness and to allow for using incomplete triads, including single‐offspring‐single‐parent families (dyads) and single offspring with no parents (monads). However, these methods usually do not preserve the full robustness of the original TDT. In this paper, we propose a new TDT‐type approach based on the conditional likelihood of the proband's genotype given the number and, if any, genotypes of the available parents, as well as the proband's phenotype. This new proposal keeps the full robust property of the original TDT. In addition, the new method is very easy to implement, without the need to specify models on parental mating‐type probabilities and on parental missingness. © 2004 Wiley‐Liss, Inc.
Decomposing the effects of children's health on mother's labor supply: is it time or money?
Authors: Gould Elise
Published: April 2004

In this paper, I explore how children's health influences the wages and work hours of their mother. Some children have illnesses that require expensive medicine or treatment, but demand little parental time. Others require extraordinary amounts of time; and still others require care at unpredictable times of the day. I construct a theoretical model of mother's labor supply that explicitly incorporates the financial and time costs associated with the presence of unhealthy children. The model predicts that children with time‐intensive illnesses and those with unpredictable illnesses negatively influence mother's labor supply, whereas children with illnesses with a strong financial component have a positive effect on mother's labor supply. In order to empirically test this, I organize a focus group of doctors to categorize illnesses and disabilities by the type of resources they require. Using the 1997 PSID Child Development Supplement, I estimate the effects of these requirements on mother's decision to work and work hours. After controlling for the financial burden of the illness, single mothers work fewer hours if their child has a time‐intensive illness and married mothers are less likely to work and work fewer hours if their child has a severe condition with an unpredictable time component. These findings are consistent with the theoretical model and highlight the need to decompose the effects of child health on mother's work status. Model specifications that aggregate across illnesses are incapable of disentangling these effects and may therefore underestimate the welfare costs of having a sick child in the family. Copyright © 2004 John Wiley & Sons, Ltd.
Are QALYs based on time trade‐off comparable? – A systematic review of TTO methodologies
Authors: Arnesen Trude , Trommald Mari
Published: April 2004

A wide range of methods is used to elicit quality‐of‐life weights of different health states to generate ‘Quality‐adjusted life years’ (QALYs). The comparability between different types of health outcomes at a numerical level is the main advantage of using a ‘common currency for health’ such as the QALY. It has been warned that results of different methods and perspectives should not be directly compared in QALY league tables. But do we know that QALYs are comparable if they are based on the same method and perspective?

The Time trade‐off (TTO) consists in a hypothetical trade‐off between living shorter and living healthier. We performed a literature review of the TTO methodology used to elicit quality‐of‐life weights for own, current health. Fifty‐six journal articles, with quality‐of‐life weights assigned to 102 diagnostic groups were included. We found extensive differences in how the TTO question was asked. The time frame varied from 1 month to 30 years, and was not reported for one‐fourth of the weights. The samples in which the quality‐of‐life weights were elicited were generally small with a median size of 53 respondents. Comprehensive inclusion criteria were given for half the diagnostic groups. Co‐morbidity was described in less than one‐tenth of the groups of respondents. For two‐thirds of the quality‐of‐life weights, there was no discussion of the influence of other factors, such as age, sex, employment and children. The different methodological approaches did not influence the TTO weights in a predictable or clear pattern. Whether or not it is possible to standardise the TTO method and the sampling procedure, and whether or not the TTO will then give valid quality‐of‐life weights, remains an open question.

This review of the TTO elicited on own behalf, shows that limiting cost–utility analysis to include only quality life weights from one method and one perspective is not enough to ensure that QALYs are comparable. Copyright © 2004 John Wiley & Sons, Ltd.
Thy1-positive mesenchymal cells promote the maturation of CD49f-positive hepatic progenitor cells in the mouse fetal liver
Authors: Hoppo Toshitaka , Fujii Hideaki , Hirose Tetsuro , Yasuchika Kentaro , Azuma Hisaya , Baba Shinji , Naito Masato , Machimoto Takafumi , Ikai Iwao
Published: April 2004

Previously, we reported a system to enrich mouse fetal hepatic progenitor cells (HPCs) by forming cell aggregates. In this study, we sorted two cell populations, CD49f+Thy1−CD45− cells (CD49f-postive cells) and CD49f±Thy1+CD45− cells (Thy1-positive cells), from the cell aggregates using a flow cytometer. CD49f-positive cells stained positive for endodermal specific markers such as α-fetoprotein (AFP), albumin (ALB), and cytokeratin 19 (CK19), and are thus thought to be HPCs. However, Thy1-positive cells were a morphologically heterogeneous population; reverse-transcription polymerase chain reaction (RT-PCR) and immunocytochemical analyses revealed the expression of mesenchymal cell markers such as α-smooth muscle actin, desmin, and vimentin, but not of AFP, ALB, or CK19. Therefore, Thy1-positive cells were thought to be of a mesenchymal lineage. When these two cell populations were co-cultured, the CD49f-positive colonies matured morphologically and stored a significant amount of glycogen. Furthermore, real-time RT-PCR demonstrated an increased expression of tyrosine amino transferase and tryptophan oxygenase mRNA, and transmission electron microscopy confirmed that co-cultured cells produced mature hepatocytes. However, when CD49f-positive cells were cultured alone or when the two populations were cultured separately, the CD49f-positive cells did not mature. These results indicate that CD49f-positive cells are primitive hepatic endodermal cells with the capacity to differentiate into hepatocytes, and that Thy1-positive cells promote the maturation of CD49f-positive cells by direct cell-to-cell contact. In conclusion, we were able to isolate CD49f-positive primitive hepatic endodermal cells and Thy1-positive mesenchymal cells and to demonstrate the requirement of cell-to-cell contact between these cell types for the maturation of the hepatic precursors. (Hepatology 2004;39:1362-1370.)
Activation of hepatic Nrf2 in vivo by acetaminophen in CD-1 mice
Authors: Goldring Christopher E. P. , Kitteringham Neil R. , Elsby Robert , Randle Laura E. , Clement Yuri N. , Williams Dominic P. , McMahon Michael , Hayes John D. , Itoh Ken , Yamamoto Masayuki , Park Kevin B.
Published: April 2004

The transcription factor NF-E2-related factor 2 (Nrf2) plays an essential role in the mammalian response to chemical and oxidative stress through induction of hepatic phase II detoxification enzymes and regulation of glutathione (GSH). Enhanced liver damage in Nrf2-deficient mice treated with acetaminophen suggests a critical role for Nrf2; however, direct evidence for Nrf2 activation following acetaminophen exposure was previously lacking. We show that acetaminophen can initiate nuclear translocation of Nrf2 in vivo, with maximum levels reached after 1 hour, in a dose dependent manner, at doses below those causing overt liver damage. Furthermore, Nrf2 was shown to be functionally active, as assessed by the induction of epoxide hydrolase, heme oxygenase-1, and glutamate cysteine ligase gene expression. Increased nuclear Nrf2 was found to be associated with depletion of hepatic GSH. Activation of Nrf2 is considered to involve dissociation from a cytoplasmic inhibitor, Kelch-like ECH-associated protein 1 (Keap1), through a redox-sensitive mechanism involving either GSH depletion or direct chemical interaction through Michael addition. To investigate acetaminophen-induced Nrf2 activation we compared the actions of 2 other GSH depleters, diethyl maleate (DEM) and buthionine sulphoximine (BSO), only 1 of which (DEM) can function as a Michael acceptor. For each compound, greater than 60% depletion of GSH was achieved; however, in the case of BSO, this depletion did not cause nuclear translocation of Nrf2. In conclusion, GSH depletion alone is insufficient for Nrf2 activation: a more direct interaction is required, possibly involving chemical modification of Nrf2 or Keap1, which is facilitated by the prior loss of GSH. (Hepatology 2004;39:1267-1276.)
The zonal distribution of megamitochondria with crystalline inclusions in nonalcoholic steatohepatitis
Authors: Le Tri H. , Caldwell Stephen H. , Redick Jan A. , Sheppard Bonnie L. , Davis Christine A. , Arseneau Kristen O. , Iezzoni Julia C. , Hespenheide Elizabeth E. , Al-Osaimi Abdullah , Peterson Theresa C.
Published: April 2004

Megamitochondria with crystalline inclusions (MMC) have been previously described in nonalcoholic fatty liver; however, their distribution within hepatic zones is unknown. We sought to determine this distribution from the core liver biopsy specimens of 31 patients: 8 males and 23 females, age range 21 to 72 years. Twenty-nine showed evidence of nonalcoholic steatohepatitis (NASH) on biopsy with steatosis, inflammation, varying degree of fibrosis, ballooned hepatocytes, and Mallory hyaline, and two patients had cryptogenic cirrhosis thought to represent “burned out” NASH. Identified by transmission electron microscopy, the abundance of MMC was compared between low-stage (fibrosis stages 1 and 2) and high-stage (fibrosis stages 3 and 4) groups and between zones with or without difference in fibrosis stage. Regardless of stage, the MMC were distributed equally in all zones and were abundant similarly in low- and high-stage groups. This abundance did not correlate with the degree of oxidative stress (4-hydroxynonenal staining) or with the abundance of ballooned hepatocytes. Consistent with age as a risk factor for more severe disease, the median age for the low-stage group was significantly lower than that of the high-stage group (P = .003). In conclusion, in NASH, the MMC seem to be distributed randomly among zones and without variation in abundance, regardless of the fibrosis stage. The exact function of these structures remains to be defined. In this study, their presence did not seem to correlate with the light microscopic injury pattern represented by ballooned hepatocytes or degree of oxidative stress defined by immunostaining for 4-hydroxynonenal. (Hepatology 2004;39:1423-1429.)
Liver NK cells expressing TRAIL are toxic against self hepatocytes in mice
Authors: Ochi Makoto , Ohdan Hideki , Mitsuta Hiroshi , Onoe Takashi , Tokita Daisuke , Hara Hidetaka , Ishiyama Kohei , Zhou Wendy , Tanaka Yuka , Asahara Toshimasa
Published: April 2004

Although it is known that activation of natural killer (NK) cells causes liver injury, the mechanisms underlying NK cell-induced killing of self-hepatocytes are not clear. We demonstrated that liver NK cells have cytotoxicity against normal syngeneic hepatocytes in mice. Polyinosinic-polycytidylic acid (poly I:C) treatment enhanced hepatocyte toxicity of liver NK cells but not that of spleen NK cells. Unlike NK cells in other tissues, approximately 30%-40% of liver NK cells constitutively express tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). An in vitro NK cell cytotoxic assay revealed that hepatocyte toxicity of liver NK cells from both naïve and poly I:C-treated mice was inhibited partially by an anti-TRAIL monoclonal antibody (mAb) alone and completely by the combination with anti-Fas ligand (FasL) mAb and a perforin inhibitor, concanamycin A, indicating contribution of TRAIL to NK cell-mediated hepatocyte toxicity. The majority of TRAIL+ NK cells lacked expression of Ly-49 inhibitory receptors recognizing self-major histocompatibility complex class I, indicating a propensity to targeting self-hepatocytes. Poly I:C treatment significantly upregulated the expression of Ly-49 receptors on TRAIL− NK cells. This might be a compensatory mechanism to protect self-class I-expressing cells from activated NK cell-mediated killing. However, such compensatory alteration was not seen at all in the TRAIL+ NK cell fraction. Thus, liver TRAIL+ NK cells have less capacity for self-recognition, and this might be involved in NK cell-dependent self-hepatocyte toxicity. In conclusion, our findings are consistent with a model in which TRAIL-expressing NK cells play a critical role in self-hepatocyte killing through poor recognition of MHC. (Hepatology 2004;39:1321-1331.)
Improved prediction of fibrosis in chronic hepatitis C using measures of insulin resistance in a probability index
Authors: Sud Archana , Hui Jason M. , Farrell Geoffrey C. , Bandara Priyanka , Kench James G. , Fung Carolyn , Lin Rita , Samarasinghe Dev , Liddle Christopher , McCaughan Geoffrey W. , George Jacob
Published: April 2004

We sought to develop a clinically useful index comprising standard and physiologically relevant variables to predict the probability of significant hepatic fibrosis in subjects with chronic hepatitis C virus (HCV) infection. Fibrosis was graded as mild (stages F0 or F1) or significant (stages F2-F4). Thirty-five clinical and laboratory parameters were analyzed initially in 176 patients with detectable HCV RNA to derive a fibrosis probability index (FPI) to predict significant fibrosis. This index then was validated in a second group of 126 subjects. Among 18 variables associated with severe fibrosis on univariate analysis, multiple logistic regression analysis identified age, aspartate aminotransferase (AST), total cholesterol level, insulin resistance (by homeostasis model), and past alcohol intake as independent predictors of significant fibrosis. The area under the receiver operating characteristic (ROC) curves was 0.84 for the initial cohort and 0.77 for the validation cohort. In the initial cohort, the sensitivity of the FPI based on these five predictors was 96%, and the negative predictive value was 93% at a score of ≥0.2. At scores ≥0.8, the FPI was 94% specific and had a positive predictive value of 87%. In conclusion, an FPI using routinely assessed markers and incorporating a measure of insulin resistance can reliably predict the probability of significant hepatic fibrosis in most patients with chronic HCV infection. Such an index should prove useful to guide decision making regarding the need for liver biopsy, and potentially for avoiding or deferring biopsy in a large proportion of patients with mild liver disease. (Hepatology 2004;39:1239-1247.)
Low membrane protein sulfhydrils but not G6PD deficiency predict ribavirin-induced hemolysis in hepatitis C
Authors: Grattagliano Ignazio , Russmann Stefan , Palmieri Vincenzo O. , Jüni Peter , Bihl Florian , Portincasa Piero , Palasciano Giuseppe , Lauterburg Bernhard H.
Published: April 2004

Hemolysis is a frequent adverse effect of ribavirin (RBV). It has been suggested that oxidative stress plays a role, but mechanisms and predictive risk factors for severe forms remain unknown. Markers of redox status were determined in erythrocytes of 34 patients with hepatitis C—four of them with glucose-6-phosphate-dehydrogenase (G6PD) deficiency—before and during treatment with RBV and interferon (IFN) and were compared with 10 healthy control subjects. In addition, erythrocytes were incubated with RBV, and the effects of dipyridamole (DPD), diethylmaleate (DEM), and glutathione ester (GSHE) were studied in vitro. Of the 30 patients without G6PD deficiency who were treated with RBV and IFN-α, five developed major hemolysis (Δ hemoglobin > 6 g/dL) and 25 developed minor hemolysis (Δ hemoglobin < 2.5 g/dL). Patients with major hemolysis had lower median pretreatment values of membrane protein sulfhydrils than patients with minor hemolysis (28.4 vs. 36.7 nmol/mg, P < .001). Erythrocytes of G6PD-deficient patients were not more susceptible to RBV-induced hemolysis. In in vitro incubations of erythrocytes, DEM enhanced the RBV-induced decrease of glutathione, protein sulfhydrils, and osmotic resistance. Supplementation of GSHE and DPD prevented the RBV-induced decrease in osmotic resistance, adenosyl triphosphate (ATP), and 2,3-diphosphoglycerate (DPG), the loss of glutathione and protein sulfhydrils, and the formation of thiobarbituric acid reactive substances (TBARs). In conclusion, the data indicate that low membrane protein sulfhydrils prior to therapy but not G6PD deficiency are predictive of RBV-induced major hemolysis. In vitro, GSHE and DPD reduce the RBV-associated oxidative stress in erythrocytes and prevent the increase in osmotic fragility, suggesting that these compounds might decrease the risk of hemolysis in patients. (Hepatology 2004;39:1248-1255.)
New ent‐Abietanoids from Isodon rubescens
Authors: Han Quan‐Bin , Li Rong‐Tao , Zhang Ji‐Xia , Sun Han‐Dong
Published: April 2004

Six new ent‐abietane diterpenoids, rubescensins I–M (1–5) and P (6), along with two related acetonide derivatives (7 and 8), were isolated from Isodon rubescens. Their structures were elucidated by detailed spectroscopic analysis. Compound 5 is the first N‐containing diterpenoid from the genus Isodon, exhibiting notable cytotoxicity against human tumor K562 cells.
Diastereoselective Electrophilic Amination of Chiral 1‐Benzoyl‐2,3,5,6‐tetrahydro‐3‐methyl‐2‐(1‐methylethyl)pyrimidin‐4(1H)‐one for the Asymmetric Syntheses of α‐Substituted α,β‐Diaminopropanoic Acids
Authors: Castellanos Elena , Reyes‐Rangel Gloria , Juaristi Eusebio
Published: April 2004

The chiral compounds (R)‐ and (S)‐1‐benzoyl‐2,3,5,6‐tetrahydro‐3‐methyl‐2‐(1‐methylethyl)pyrimidin‐4(1H)‐one ((R)‐ and (S)‐1), derived from (R)‐ and (S)‐asparagine, respectively, were used as convenient starting materials for the preparation of the enantiomerically pure α‐alkylated (alkyl=Me, Et, Bn) α,β‐diamino acids (R)‐ and (S)‐11–13. The chiral lithium enolates of (R)‐ and (S)‐1 were first alkylated, and the resulting diasteroisomeric products 5–7 were aminated with ‘di(tert‐butyl) azodicarboxylate’ (DBAD), giving rise to the diastereoisomerically pure (≥98%) compounds 8–10. The target compounds (R)‐ and (S)‐11–13 could then be obtained in good yields and high purities by a hydrolysis/hydrogenolysis/hydrolysis sequence.
Reaction of Phenanthrene‐9,10‐dione with Phenanthrene‐9,10‐diol: Synthesis and Characterization of the First ortho‐Quinhydrone Derivative
Authors: Calderazzo Fausto , Forte Claudia , Marchetti Fabio , Pampaloni Guido , Pieretti Laura
Published: April 2004

Treatment of phenanthrene‐9,10‐dione (PQ) with phenanthrene‐9,10‐diol (PQH2), as prepared by catalytic hydrogenation of PQ, in toluene solution or in the solid state afforded crystalline ‘9,10‐phenanthrenequinhydrone’ (PQH), the first example of an ortho‐quinhydrone. PQH was characterized by analytical and spectroscopic methods, including X‐ray and CP/MAS 13C‐NMR analyses. The crystal structure of PQH showed pairs of planar molecules linked by H‐bonds and organized in columns parallel to the crystallographic axis a. The solid‐state structure of PQH was compared with those of the parent compounds, PQ and PQH2, the latter being reported for the first time. PQH was found to be stable in the solid state only, the components PQ and PQH2 being formed upon dissolution in media of even low polarity such as toluene.
Reactions of Sulfanyl Chlorides with Thiocamphor and Thiofenchone: WagnerMeerwein Rearrangement of an Intermediate Thiocarbonylium Ion
Authors: Majchrzak Agnieszka , Mlostoń Grzegorz , Linden Anthony , Heimgartner Heinz
Published: April 2004

The reaction of sulfanyl and disulfanyl chlorides with thiocamphor (6) in the presence of Et3N leads to unsymmetrical di‐ and trisulfanes, respectively (Schemes 2 and 4). A reaction mechanism via a thiocarbonylium ion, which is immediately deprotonated, is proposed. The formation of a minor product 10 in the absence of a base, resulting from a WagnerMeerwein rearrangement, is an additional evidence for the intermediacy of a thiocarbonylium ion (Scheme 3). On the other hand, the non‐enolizable thiofenchone (13) reacts with sulfanyl chlorides in CH2Cl2/Et3N to give exclusively products with a rearranged bicyclic skeleton (Scheme 5). A WagnerMeerwein rearrangement of the intermediate thiocarbonylium ion is the key step. The structures of the products 10 and 14, which have rearranged bicyclic systems, have been established by X‐ray crystallography.
Novel Naphthoquinones from Heterophragma adenophyllum
Authors: Jassbi Amir Reza , Singh Pahup , Jain Sonakshi , Tahara Satoshi
Published: April 2004

A new symmetric naphthoquinone dimer, dilapachone (1), and a novel asymmetric naphthoquinone dimer, adenophyllone (2), were isolated from the heartwood of Heterophragma adenophyllum. Their structures were elucidated by spectroscopic means including high‐resolution mass, UV, IR, 1D‐ and 2D‐NMR spectroscopy.
Structure‐Based Design and Synthesis of Regioisomeric Disubstituted Aminoanthraquinone Derivatives as Potential Anticancer Agents
Authors: Huang Hsu‐Shan , Chiu Hui‐Fen , Yeh Pen‐Fong , Yuan Chun‐Lung
Published: April 2004

Continuing our ongoing studies on cytotoxic substances, we report the synthesis and cytotoxic properties of a series of symmetric 1,5‐diamino‐9,10‐anthraquinones with potentially bioreducible groups. Symmetric amination of 1,5‐dichloro‐9,10‐anthraquinone with the appropriate primary amines in the presence of DMF furnished the structurally related aminoanthraquinone analogs 1–19. Their in vitro cytotoxic activity was evaluated using rat glioma C6 cells, human hepatoma G2 cells, and 2.2.15 cells. Several compounds exhibited very high antitumor activities in these assays. Compound 4 efficiently inhibited C6 cells, human hepatoma G2 cells, and 2.2.15 cells, as determined by means of the XTT colorimetric assay. The antiproliferative activity of 4 was markedly enhanced, reaching a potency comparable to those of the powerful anticancer agents mitoxantrone, adriamycin, and cisplatin. Biological evaluations and structure/activity relationships within this class of novel aminoanthraquinones are discussed.
Osteoblast responses to tape‐cast and sintered bioactive glass ceramics
Authors: Gough J. E. , Clupper D. C. , Hench L. L.
Published: April 2004

The advantage of tape‐cast bioactive glasses lies in the manufacturing procedure, which allows the build‐up of layers and, therefore, the production of complex shapes. This, therefore, has applications to tissue engineering, where specific shapes are required such as repair of craniofacial defects. The bioactivity of tape‐cast discs sintered at temperatures ranging from 800°C to 1000°C and for 3 or 6 h was analyzed by FTIR. Tape‐cast discs were used to culture primary human osteoblasts, and cell attachment, cell death, collagen production, nodule formation, and mineralization were studied. These responses were dependent upon Si and Na release profiles of the tape‐cast discs, and development of the hydroxyapatite layer. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 621–628, 2004
Ultrastructural comparison of dissolution and apatite precipitation on hydroxyapatite and silicon‐substituted hydroxyapatite in vitro and in vivo
Authors: Porter Alexandra E. , Botelho Claudia M. , Lopes Maria A. , Santos José D. , Best Serena M. , Bonfield William
Published: April 2004

Recent histological studies have demonstrated that the substitution of silicate ions into hydroxyapatite (HA) significantly increases the rate of bone apposition to HA implants. The enhanced bioactivity of silicon‐substituted HA (Si‐HA) over pure HA has been attributed to the effect of silicate ions in accelerating dissolution. In the present study, high‐resolution transmission electron microscopy (HR‐TEM) was employed to compare dissolution of HA and Si‐HA in an acellular simulated body fluid (SBF) to dissolution in an in vivo model. HR‐TEM observations confirmed a difference in morphology of apatite precipitates in vivo and in SBF: apatite deposits were platelike in vivo and nodular in SBF. Compositional mapping suggested that preferential dissolution of silicon from the implant promotes the nucleation of carbonate apatite around the implant. The in vivo findings illustrated an absence of dissolution at the bone–HA or Si–HA interface, whereas dissolution was extensive from within the implant. The amount of dissolution in acellular SBF was similar to dissolution from within the implant, although the site at which the dissolution nucleates was different: dissolution predominates at the crystallite surfaces in SBF, whereas grain boundary dissolution predominates in vivo. These findings suggest that proteins in the in vivo milieu modify the processes of dissolution from the implant. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 670–679, 2004
The role of implant alignment on stability and particles on periprosthetic osteolysis—A rabbit model of implant failure
Authors: Fornasier V. L. , Goodman S. B. , Protzner K. , Kamel M. , Song Y. , Shojaci A.
Published: April 2004

The study objective was to determine the tissue response to polyethylene and/or titanium particles and the role that these play in peri‐prosthetic osteolysis in a rabbit model of implant failure. Twenty‐two mature rabbits were used. Unilateral tibial arthroplasty was performed on all of them. The test animals received implants that were intentionally rotationally unstable with reference to the host tibia in order to create a model of failure. The test rabbits were divided into three groups. Group 1 consisted of seven rabbits in which only the carrier was implanted. Group 2 consisted of seven rabbits that received only polyethylene particles suspended in the carrier. Group 3 consisted of eight rabbits that received a mixture of polyethylene and titanium alloy particles suspended in the carrier. The rabbits were sacrificed at 6 months post surgery. The entire knee, together with the immediately surrounding soft tissue, was retrieved. The position of the implant in each rabbit was assessed with reference to its alignment to the tibia. The number of inflammatory, foreign‐body reactive cells, the presence of neovascularization, edema, and necrosis in the periprosthetic zones were recorded and assessed in a qualitative and semiquantitative manner. Quantitative histomorphometry was used to determine the proportion of implant surface that interfaced with osseous or fibrous tissue. Also assessed was the thickness and maturity of the fibrous tissue and the endosteal remodeling activity in the peri‐implant bone counting both osteoclastic and osteoblastic activity. The results showed that implanted particles and misalignment of the implants combined to produce peri‐prosthetic bone resorption. Bone resorption was found to be proportional to the degree of misalignment. The animals that received combined polyethylene/titanium particles had a greater degree of foreign‐body and inflammatory response with osteolysis than the other groups. The combination of bio‐material particles (polyethylene and titanium alloy) produced a greater degree of bone resorption than the single biomaterial particles (polyethylene). The amount of bone resorption surrounding the implant was directly proportional to the degree of misalignment of the implant. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 179–186, 2004