bluuebunny/crossref_metadata_2025_split huggingface dataset:
Obstructive jaundice caused by hepatocellular carcinoma: Detection by endoscopic sonography
Authors: Lee Yi‐Chia , Wang Hsiu‐Po , Huang Shih‐Pei , Chang Yu‐Ting , Wu Chen‐Tu , Yang Chang‐Shyue , Wu Ming‐Shiang , Lin Jaw‐Town 
Published: August 2002

AbstractTumor thrombus in the extrahepatic biliary tree is a rare mechanism of obstructive jaundice. We present a patient with a minute hepatocellular carcinoma in the caudate lobe that invaded the common hepatic duct and caused biliary obstruction. Endoscopic sonography showed a tumor thrombus with central echogenicity and a “nodule‐in‐nodule” pattern and suggested the correct diagnosis. © 2001 John Wiley & Sons, Inc. J Clin Ultrasound 29:363–366, 2001.
A review of the epidemiological evidence on health effects of nitrogen dioxide exposure from gas stoves
Authors: Basu R. , Samet J.M. 
Published: August 2002

AbstractThis review addresses the evidence on the health effects of exposure to emissions of NO2 from gas stoves, covering findings of 45 epidemiological studies. These studies had addressed diverse outcome measures, including the risks of acute respiratory illness, decreased pulmonary function, respiratory symptoms and asthma exacerbation. Although most studies have focused on schoolchildren, studies of adults and more recently, prospective studies of infants have also been carried out. The findings have not been consistent across all studies in showing adverse effects. We conclude that the evidence does not support a causal relationship between exposure NO2 or use of a gas stove and increased risk for respiratory morbidity at the levels of NO2 typically associated with gas stoves. Some studies do show increased risk for respiratory health effects, however, and the evidence does not support the conclusion that NO2 emitted by gas stoves is risk‐free. Further research would be indicated if populations receiving exposures in a range of interest can be identified. Copyright © 1999 John Wiley & Sons, Ltd.This review addresses the evidence on the health effects of exposure to emissions of NO2 from gas stoves, covering findings of 45 epidemiological studies. These studies had addressed diverse outcome measures, including the risks of acute respiratory illness, decreased pulmonary function, respiratory symptoms and asthma exacerbation. Although most studies have focused on schoolchildren, studies of adults and more recently, prospective studies of infants have also been carried out. The findings have not been consistent across all studies in showing adverse effects. We conclude that the evidence does not support a causal relationship between exposure NO2 or use of a gas stove and increased risk for respiratory morbidity at the levels of NO2 typically associated with gas stoves. Some studies do show increased risk for respiratory health effects, however, and the evidence does not support the conclusion that NO2 emitted by gas stoves is risk‐free. Further research would be indicated if populations receiving exposures in a range of interest can be identified. Copyright © 1999 John Wiley & Sons, Ltd.
The use and misuse of surrogate variables in environmental epidemiology
Authors: Lipfert Frederick W. 
Published: August 2002

AbstractThis paper discusses some common statistical problems that are often encountered in the specification and interpretation of regression models used in environmental epidemiology; such models have been used to establish new or modified ambient standards intended to protect public health. These statistical problems include: collinearity (identifying the ‘correct’ pollutant), confounding (omission of other variables that may be correlated with both response and putative dose), the ‘ecological fallacy’ (aggregating individual doses and responses over space or time), measurement error (uncertainties in data, applicability and measurement per se) and linearity (identifying curvature or thresholds in dose‐response function). These problems occur in both time‐series and cross‐sectional studies. Although none of these potential problem areas is new, they have rarely been considered together or comprehensively. This paper considers them as specific instances of the general problem of surrogate variables, for which an analytical framework is presented together with some examples of their practical consequences and some guidelines for interpreting environmental epidemiology studies. Findings of the analysis include: single‐pollutant regression models are likely to overstate effects; although aggregation results in loss of information, it biases the estimates only when confounding is present; the traditional approaches to correcting for measurement errors implied by the difference between personal exposures and ambient air quality do not apply, but estimates may be based on consideration of the ‘error’ term as an additional source of exposure; it may not be possible to deduce the correct shape of a dose‐response function in the presence of measurement error and correlated covariates. These findings are intended to be descriptive rather than definitive; the main purpose is to stimulate the detailed research required to develop practical remedies that would allow epidemiology to be used appropriately in setting environmental standards.Copyright © 1999 John Wiley & Sons, Ltd.
Characterization of GFP‐MAL expression and incorporation in rafts
Authors: Caduff J. , Sansano S. , Bonnet A. , Suter U. , Schaeren‐Wiemers N. 
Published: August 2002

AbstractDuring myelin formation, membrane‐associated proteins have to be sorted and transported in specified membrane regions such as compact and non‐compact myelin membranes. One protein that may be involved in such a process is the Myelin and Lymphocyte protein MAL (VIP17/ MVP17). MAL was identified as a novel myelin membrane component expressed by oligodendrocytes and Schwann cells. Since MAL has been shown to be important in the apical sorting machinery of polarized cells, we have started to investigate the possible functional role of MAL in sorting myelin membrane‐associated molecules. In this study, we have generated cDNA constructs with green fluorescent protein (GFP) either at the N‐ or C‐terminus of MAL. Transfection experiments showed that GFP‐MAL expression resembles that of normal MAL, whereas the MAL‐GFP fusion construct was not properly transported within the cell. Furthermore, we could demonstrate that GFP‐MAL is enriched in detergent insoluble glycolipid‐enriched microdomains as already seen for untagged MAL. As a prerequisite for the generation of transgenic mice expressing GFP‐MAL under the control of its own regulatory elements, we have generated a cDNA construct with an 8‐kb MAL promotor fragment fused to GFP‐MAL. Transfection experiments of the Oli‐neu oligodendrocyte cell line showed that GFP‐MAL was expressed, but only in cells, which were stimulated for differentiation with cAMP. In summary, the results confirm that the fusion protein GFP‐MAL is incorporated into detergent‐insoluble complexes and the 8‐kb MAL promotor fragment is sufficient to be activated in oligodendrocytes. Microsc. Res. Tech. 52:645–655, 2001. © 2001 Wiley‐Liss, Inc.
Testing the vulnerability of the phylotypic stage: On modularity and evolutionary conservation
Authors: Galis Frietson , Metz Johan A.J. 
Published: August 2002

AbstractThe phylotypic stage is the developmental stage at which vertebrates most resemble each other. In this study we test the plausibility of the hypotheses of Sander [1983, Development and Evolution, Cambridge University Press] and Raff [1994, Early Life on Earth, Columbia University Press; 1996, The Shape of Life, University of Chicago Press] that the phylotypic stage is conserved due to the intense and global interactivity occurring during that stage. First, we test the prediction that the phylotypic stage is much more vulnerable than any other stage. A search of the teratological literature shows that disturbances at this stage lead to a much higher mortality than in other stages, in accordance with the prediction. Second, we test whether that vulnerability is indeed caused by the interactiveness and lack of modularity of the inductions or, alternatively, is caused by some particularly vulnerable process going on at that time. From the pattern of multiple induced anomalies we conclude that it is indeed the interactiveness that is the root cause of the vulnerability. Together these results support the hypotheses of Sander and Raff. We end by presenting an argument on why the absence of modularity in the inductive interactions may also be the root cause of the conservation of the much discussed temporal and spatial colinearity of the Hox genes. J. Exp. Zool. (Mol. Dev. Evol.) 291:195–204, 2001. © 2001 Wiley‐Liss, Inc.
Sex reversal and aromatase in the European pond turtle: Treatment with letrozole after the thermosensitive period for sex determination
Authors: Belaid Baya , Richard‐Mercier Noelle , Pieau Claude , Dorizzi Mireille 
Published: August 2002

AbstractIn the European pond turtle (Emys orbicularis), gonadal sex differentiation is temperature‐dependent. The temperature sensitive period (TSP) of gonadogenesis lies between stages 16 and 22 of embryonic development. Previous studies have shown that embryos incubated at 30°C, a temperature yielding 100% phenotypic females, can be sex reversed by treatments with an aromatase inhibitor administered during TSP or even somewhat after TSP (as of stage 22+).The goal of the present study was to determine whether the ovary still retains male potential at later stages of embryonic development and whether the induced male characters persist after hatching. For this purpose, eggs of E. orbicularis were treated with letrozole, a nonsteroidal aromatase inhibitor, at or as of stages 23, 24 or 25, then gonadal aromatase activity in each individual and the related gonadal structure were studied at hatching (stage 26) and for one year after hatching. Two kinds of treatments were carried out: 1) repeated applications of 10 μg of letrozole in ethanolic solution onto the eggshell; and 2) a single injection of 10 μg of letrozole in olive oil. Similar results were obtained with either application or injection of the aromatase inhibitor. In treatments as of or at stage 23, individuals with gonadal aromatase activity lower than 20 fmoles/hour/gonad had ovotestes, i.e., 22% of the treated individuals. At hatching, the inner part of these ovotestes contained testicular cords and also mixed lacunae presenting various degrees of transdifferentiation of the epithelium into a Sertolian epithelium. The cortex was maintained, although some germ cells degenerated within it. These processes continued after hatching. However, at 12 months, gonads were still ovotestes displaying some follicles with a growing oocyte in the remaining parts of the cortex. In treatments as of or at stages 24 or 25, only a few individuals were masculinized. One had ovotestes; in others, the cortex was absent in some parts and when it was present oocytes were degenerating. These results show that in the European pond turtle, differentiation of ovotestes from ovaries can be induced by treatment with an aromatase inhibitor starting at late stages of embryonic development (between the end of TSP and hatching), although such differentiation is less frequent as embryonic development proceeds. Sex reversal persists for at least one year after hatching. J. Exp. Zool. 290:490–497, 2001. © 2001 Wiley‐Liss, Inc.
Obstruction sets for outer‐cylindrical graphs
Authors: Archdeacon Dan , Bonnington C. Paul , Dean Nathaniel , Hartsfield Nora , Scott Katherine 
Published: August 2002

AbstractA graph is outer‐cylindrical if it embeds in the sphere so that there are two distinct faces whose boundaries together contain all the vertices. The class of outer‐cylindrical graphs is closed under minors. We give the complete set of 38 minor‐minimal non‐outer‐cylindrical graphs, or equivalently, an excluded minor characterization of outer‐cylindrical graphs. We also give the obstruction sets under the related topological ordering and Y Δ‐ordering. © 2001 John Wiley & Sons, Inc. J Graph Theory 38: 42–64, 2001
Comparative study of the cuticle in some aquatic oligochaetes (Annelida: Clitellata)
Authors: Gustavsson Lena M. 
Published: August 2002

AbstractAn examination of the cuticle of six aquatic oligochaete species using transmission electron microscopy revealed a larger morphological variation than previously known. Three freshwater species, Aulodrilus pluriseta, Spirosperma ferox (both Tubificidae), and Pristina breviseta (Naididae), and three marine species, Clitellio arenarius, Heterochaeta costata (both Tubificidae), and Paranais litoralis (Naididae), were investigated. The arrangement of the collagen fibers in the cuticle differs among the studied species. Only S. ferox shows an “orthogonal grid,” i.e., layers of parallel fibers perpendicular to each other, as earlier described for lumbricids and enchytraeids. Clitellio arenarius and H. costata have fibers arranged in layers, while A. pluriseta and P. litoralis have irregularly distributed fibers. Pristina breviseta lacks cuticular fibers. The matrix surrounding the collagen fibers (when present) continues outside the fiber layer, making up a thin epicuticle, which has a unique banding in each of the studied species. The external surface of the epicuticle is covered with epicuticular projections. Their number, shape, and attachment to the epicuticle vary among the studied species. Furthermore, a distinctive internal substructure of the projections was observed in H. costata, A. pluriseta, S. ferox, and P. breviseta. Microvilli, extensions from the epidermal cells, penetrate the cuticle and terminate at its outer surface. In three species microvilli were observed to pinch off the epicuticular projections. The size, number, and shape of the latter vary; no typical microvilli were observed in S. ferox. J. Morphol. 248:185–195, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of female intrapelvic tumors by clinical proton MR spectroscopy
Authors: Okada Toshiko , Harada Masafumi , Matsuzaki Kenji , Nishitani Hiromu , Aono Toshihiro 
Published: August 2002

AbstractWe measured metabolites in large tumors of the female pelvis (23 cases total: 6 malignant cases, 17 benign cases) using single‐voxel proton magnetic resonance (MR) spectroscopy and evaluated the clinical significance of this method in the differential diagnosis of female pelvic tumors. The characteristically obtained signal was lactate, which was detected not only in all the malignant tumors but also in some of the benign tumors. However, the lactate signals of the malignant tumors tended to form higher peaks than those of benign tumors, which was a finding consistent with the result of the earlier in vitro study reported in ovarian tumors. The signal of choline‐containing compounds (Cho) was found only in solid tumors, and the signal intensity varied among different histological types of tumors, possibly reflecting metabolic activity of the cell membrane. We considered that proton MR spectroscopy (MRS) of intrapelvic tumors would be useful for the diagnosis of the nature of female intrapelvic tumors. J. Magn. Reson. Imaging 2001;13:912–917. © 2001 Wiley‐Liss, Inc.
Functional MRI with simultaneous EEG recording: Feasibility and application to motor and visual activation
Authors: Lazeyras François , Zimine Ivan , Blanke Olaf , Perrig Stephen H. , Seeck Margitta 
Published: August 2002

AbstractThe possibility of combining the high spatial resolution of functional magnetic resonance imaging (fMRI) with the high temporal resolution of electroencephalography (EEG) may provide a new tool in cognitive neurophysiology, as well as in clinical applications such as epilepsy. However, the simultaneous recording of EEG and fMRI raises important practical problems: 1) the patients' safety, in particular the risk of skin burns due to electrodes heating; 2) the impairment of the EEG recording by the static magnetic field, as well as by RF and magnetic field gradients used during MRI; and 3) the quality of MR images, which may be affected by the presence of conductors and electronic devices in the MRI bore. Here we present our experiences on 19 normal volunteers who underwent combined fMRI and 16‐channel EEG examination. Consistent with previous reports, safety could be assured when performing EEG recordings during fMRI acquisition. Electrophysiological signals recorded with surface EEG were similar inside and outside the 1.5 T magnet. Furthermore, fMRI using motor or visual tasks revealed similar areas of activation when performed with and without 16‐channel EEG recording. J. Magn. Reson. Imaging 2001;13:943–948. © 2001 Wiley‐Liss, Inc.
Distribution of hepatitis C virus infection in liver biopsies from children and adults with chronic hepatitis C
Authors: de Lucas Susana , Bartolomé Javier , Rodríguez‐Iñigo Elena , Casqueiro Mercedes , Millán Antonio , Ruiz‐Moreno Mercedes , Oliva Horacio , Carreño Vicente 
Published: August 2002

AbstractChronic hepatitis C in children is characterized by milder forms of liver damage than those found in adults. Such a difference has been attributed to a low viral load in children that may lead to poor recognition of infected cells by the immune system. One approach that could be used to confirm this hypothesis may be to examine the number of infected hepatocytes in liver biopsies. Paraffin embedded liver biopsies from 21 children and 15 adults with chronic hepatitis C virus (HCV) infection (with a similar duration of the infection) were hybridized in situ and the percentage of infected hepatocytes was correlated with the histological activity index, alanine aminotransferase levels and HCV viraemia levels. Histological activity index and HCV viraemia levels were statistically higher (P < 0.05 and P < 0.01 respectively) in adults than in children, and the percentage of infected hepatocytes was higher in adults (11.0 ± 19.7%) than in children (4.6 ± 3.6%), although it did not reach statistical significance. Also, the percentage of infected hepatocytes correlated with HCV‐RNA concentration in serum in both children (r = 0.683, P = 0.001) and adults (r = 0.768, P = 0.001). The results show that liver damage in children with chronic hepatitis C is not related to the extent of infection in the liver. This findings support the hypothesis of that liver injury in chronic HCV infection is mediated by the host immune response. J. Med. Virol. 64:1–5, 2001. © 2001 Wiley‐Liss, Inc.
Genetic relatedness of Cuban HAV wild‐type isolates
Authors: Diaz Belkis I. , Sariol Carlos A. , Normann Andrea , Rodríguez Licel , Flehmig Bertram 
Published: August 2002

AbstractKnowledge of the nucleotide sequence in the region of the putative VP1/2A junction of the Hepatitis A virus (HAV) genome has enabled differentiation of HAV strains and their classification into seven genotypes, in some of which sub‐genotypes A and B can be defined. A 168 base segment encompassing the putative VP1/2A junction of 27 clinical wild‐type isolates of HAV from Cuba was amplified by reverse transcriptase‐polymerase chain reaction and then sequenced. The Cuban isolates are clustered within sub‐genotype IA. A single amino acid substitution, which does not correspond with any of the reported changes for other strains, was observed. A new sub‐genotype variant is therefore postulated. This study provides new data on the genetic relatedness of HAVs from Cuba and on the distribution of sub‐genotype IA in the Caribbean area. J. Med. Virol. 64:96–103, 2001. © 2001 Wiley‐Liss, Inc.
Induction of mucosal IgA following intravaginal administration of inactivated HIV‐1‐capturing nanospheres in mice
Authors: Kawamura Masaki , Naito Taichi , Ueno Masamichi , Akagi Takami , Hiraishi Katsuya , Takai Izumi , Makino Masahiko , Serizawa Takeshi , Sugimura Kazuhisa , Akashi Mitsuru , Baba Masanori 
Published: August 2002

AbstractConcanavalin A‐immobilized polystyrene nanospheres (Con A‐NS) were developed for the HIV‐1 vaccine capable of preventing sexual transmission. Con A‐NS could capture efficiently HIV‐1 irrespective of their cell tropism (R5 or X4). Furthermore, Con A‐NS captured equally infectious and heat‐inactivated HIV‐1. Inactivated HIV‐1‐capturing Con A‐NS (HIV‐NS) were intravaginally administered to mice. Heat‐inactivated HIV‐1 alone and Con A‐NS alone were also administered as control immunogens. Vaginal fluids were collected during and after immunization and analyzed for their anti‐HIV‐1 antibody levels. Although the anti‐HIV‐1 IgG antibody was undetectable in any groups, increased anti‐HIV‐1 IgA antibody response was identified in the vaginal fluids of immunized mice with HIV‐NS. The vaginal fluids obtained from the HIV‐NS‐administered mice showed neutralizing activity against the immunizing HIV‐1 strain. A marked difference in vaginal distribution was observed between HIV‐NS and other immunogens, and the toxicity of Con A was reduced by conjugation with nanospheres. Thus, HIV‐NS may have great potential as a prophylactic HIV‐1 vaccine and should be examined further for its efficacy in non‐human primates. J. Med. Virol. 66:291‐298, 2002. © 2002 Wiley‐Liss, Inc.
Hybrid modelling for echo location and surface characterization
Authors: de Cogan D. , Morton M. , Peel D. , Sant V. 
Published: August 2002

AbstractThe scattering of sound from surfaces by rotating sources such as the tips of helicopter rotor blades can be used as a method of locating and ranging obstructions which may represent a physical danger to the craft. Modelling such systems presents some difficulties but these can be overcome using a combination of TLM and phase‐coherent ray‐tracing. This paper describes the hybrid approach, particularly, the techniques for interfacing. The application to the specific problem of the scattering of rotor‐tip noise from realistic targets involved the use of a simple PML and surface‐conforming boundaries. Copyright © 2001 John Wiley & Sons, Ltd.
TLM‐based FDTD modelling of optical bistability
Authors: Hruskovec Tomislav , Chen Zhizhang 
Published: August 2002

AbstractThe TLM‐based FDTD method is extended to the modelling of optical bistability caused by the saturable Kerr‐effect of a GaAs–GaAsAl multiple quantum well (MQW) like medium. This structure is one of the possible candidates to be used as an all‐optical switch in high‐speed communication systems. The purpose of this paper is to demonstrate the capability of the TLM‐based FDTD method in handling the non‐linear medium problems, by performing a time‐domain simulation starting from the basic equations that represent the problem. A recursive formulation is derived to account for the saturable Kerr properties of the material and a physically realizable Fabry–Perot cavity is simulated. The numerical results confirm the effectiveness of the TLM‐based FDTD method for bistability modelling, and thus provide the foundations for further work and the simulation of more complicated and realistic bistable structures promising for high‐speed all‐optical digital signal processing. Copyright © 2001 John Wiley & Sons, Ltd.
Application of the argument principle method to the calculation of DFB laser diode modes
Authors: Barlow G. F. , Shore K. A. 
Published: August 2002

AbstractA convenient technique for the exact determination of the longitudinal cavity modes of a distributed feed‐back (DFB) laser is presented. The method employs the argument principle method (APM) to find the singular points of the characteristic equation derived from consideration of the counter propagating coupled modes within the cavity. The method is applied to both linear and circular grating laser diodes. Copyright © 2001 John Wiley & Sons, Ltd.