bluuebunny/crossref_metadata_2025 huggingface dataset:
Transport of inorganic phosphate in primary cultures of chondrocytes isolated from the tibial growth plate of normal adolescent chickens
Authors: Wu Licia N.Y. , Guo Yande , Genge Brian R. , Ishikawa Yoshinori , Wuthier Roy E.
Published: October 2002

This report describes Pi transport activity in chondrocytes isolated from the growth plate (GP) of normal adolescent chickens grown in primary cell culture. Our recent work showed that Pi transport in matrix vesicles (MV) isolated from normal GP cartilage was not strictly Na+‐dependent, whereas previously characterized Pi transport from rachitic GP cartilage MV was. This Na+‐dependent Pi transporter (NaPiT), a member of the Type III Glvr‐1 gene family, is expressed only transiently during early differentiation of GP cartilage, is enhanced by Pi‐deficiency, and is most active at pH 6.8. Since GP mineralization requires abundant Pi and occurs under slightly alkaline conditions, it seemed unlikely that this type of Pi transporter was solely responsible for Pi uptake during normal GP development. Therefore we asked whether the lack of strict Na+‐dependency in Pi transport seen in normal MV was also evident in normal GP chondrocytes. In fact, cellular Pi transport was found not to be strictly Na+‐dependent, except for a brief period early in the culture. Choline could equally serve as a Na+ substitute. Activity of choline‐supported Pi transport was optimum at pH 7.6–8.0. In addition, prior exposure of the cells to elevated extracellular Pi (2–3 mM) strongly enhanced subsequent Pi uptake, which appeared to depend on prior loading of the cells with mineral ions. Prevention of Pi loading by pretreatment with Pi transport inhibitors not only inhibited subsequent cellular Pi uptake, it also blocked mineral formation. Treatment with elevated extracellular Pi did not induce apoptosis in these GP chondrocytes. J. Cell. Biochem. 86: 475–489, 2002. © 2002 Wiley‐Liss, Inc.
BEACH family of proteins: Phylogenetic and functional analysis of six Dictyostelium BEACH proteins
Authors: Wang Ning , Wu Wei‐I , De Lozanne Arturo
Published: October 2002

The beige and Chediak‐Higashi syndrome (BEACH)‐domain containing proteins constitute a new family of proteins found in all eukaryotes. The function of these proteins, which include the Chediak‐Higashi syndrome (CHS) protein, Neurobeachin, LvsA, and FAN, is still poorly understood. To understand the diversity of this novel protein family, we analyzed a large array of BEACH‐family protein sequences from several organisms. Comparison of all these sequences suggests that they can be classified into five distinct groups that may represent five distinct functional classes. In Dictyostelium we identified six proteins in this family, named LvsA‐F, that belong to four of those classes. To test the function of these proteins in Dictyostelium we created disruption mutants in each of the lvs genes. Phenotypic analyses of these mutants indicate that LvsA is required for cytokinesis and osmoregulation and LvsB functions in lysosomal traffic. The LvsC‐F proteins are not required for these or other processes such as growth and development. These results strongly support the concept that BEACH proteins from different classes have distinct cellular functions. Having six distinct BEACH proteins, Dictyostelium should be an excellent model system to dissect the molecular function of this interesting family of proteins. J. Cell. Biochem. 86: 561–570, 2002. © 2002 Wiley‐Liss, Inc.
Associated proteins of lens adherens junction
Authors: Bagchi M. , Katar M. , Lewis J. , Maisel H.
Published: October 2002

Cytoplasmic proteins associated with adherens junctions were identified in the chicken ocular lens. The catenins, α, β, and γ, were present in epithelial and fiber cells, although their pattern of distribution changed with fiber cell differentiation. The sharp decline in α‐catenin with fiber cell formation and the increasing Triton‐insolubility of N‐cadherin suggests that another subtype of α‐catenin exists in the lens. J. Cell. Biochem. 86: 700–703, 2002. © 2002 Wiley‐Liss, Inc.
Role of c‐fos in the regulation of type X collagen gene expression by PTH and PTHrP: Localization of a PTH/PTHrP‐responsive region in the human COL10A1 enhancer
Authors: Riemer Silvia , Gebhard Sonja , Beier Frank , Pöschl Ernst , von der Mark Klaus
Published: October 2002

PTH and PTHrP have been shown to inhibit maturation of growth plate chondrocytes and the expression of type X collagen. In order to examine the regulatory mechanisms involved, fetal bovine growth plate chondrocytes were incubated for 24–48 h under serum‐free conditions with PTH and PTHrP and various aminoterminal, midregional, and carboxyterminal fragments of these hormones. Analysis of type X collagen mRNA levels by Northern hybridization showed a significant suppression by PTH (1–84), PTH (1–34), and PTHrP (1–40), but not by PTH (28–48) or PTH (53–84). PTH fragment (3–34) did not reduce α1(X) mRNA levels, while bis‐indolylmaleimide, an inhibitor of the protein‐kinase C pathway, did not affect α1(X) mRNA suppression by PTH, supporting the notion that the inhibition of type X collagen expression by PTH involves predominantly the adenylate cyclase pathway of the PTH/PTHrP‐receptor. Since PTH and PTHrP have been shown to induce c‐fos in osteoblasts and chondrocytes, the possibility was tested that c‐fos mediated the suppressive effect of PTH/PTHrP on collagen X expression. In fetal bovine hypertrophic chondrocytes PTH (1–34), but not PTH (3–34) nor the midregional or C‐terminal PTH fragments induced c‐fos expression. In order to identify cis‐ and trans‐acting elements in the COL10A1 gene involved in c‐fos‐mediated inhibition of collagen X expression by PTH/PTHrP, reporter gene constructs carrying various fragments of the human COL10A1 promoter coupled to the luciferase gene were transfected into hypertrophic chondrocytes. A tissue‐specific, strong enhancer region, which we had previously located in the promoter of the human type X collagen gene COL10A1, was further narrowed down to a 530‐bp sequence, located between − 1,870‐ and − 2,407 bp upstream of the transcription start site. The transcriptional activity of this enhancer element in transfected hypertrophic chondrocytes was significantly reduced after incubation with PTH (1–34) or PTHrP (1–40). Transcription of these reporter genes was also inhibited when chondrocytes were cotransfected with a c‐fos expression vector. These results indicate the presence of a PTH/PTHrP responsive element in the human COL10A1 enhancer, which may be represented by multiple putative AP‐1 sites located in this region. J. Cell. Biochem. 86: 688–699, 2002. © 2002 Wiley‐Liss, Inc.
Fanconi anemia protein complex is a novel target of the IKK signalsome
Authors: Otsuki Tetsuya , Young David B. , Sasaki Dennis T. , Pando Matthew P. , Li Jianwu , Manning Anthony , Hoekstra Merl , Hoatlin Maureen E. , Mercurio Frank , Liu Johnson M.
Published: October 2002

Fanconi anemia (FA), a genetic disorder predisposing to aplastic anemia and cancer, is characterized by hypersensitivity to DNA‐damaging agents and oxidative stress. Five of the cloned FA proteins (FANCA, FANCC, FANCE, FANCF, FANCG) appear to be involved in a common functional pathway that is required for the monoubiquitination of a sixth gene product, FANCD2. Here, we report that FANCA associates with the IκB kinase (IKK) signalsome via interaction with IKK2. Components of the FANCA complex undergo rapid, stimulus‐dependent changes in phosphorylation, which are blocked by kinase‐inactive IKK2 (IKK2 K > M). When exposed to mitomycin C, cells expressing IKK2 K > M develop a cell cycle abnormality characteristic of FA. Thus, FANCA may function to recruit IKK2, thus providing the cell a means of rapidly responding to stress. J. Cell. Biochem. 86: 613–623, 2002. © 2002 Wiley‐Liss, Inc.
Countertransference management and therapy outcome: An initial evaluation
Authors: Gelso Charles J. , Latts Mara G. , Gomez Maria J. , Fassinger Ruth E.
Published: October 2002

The relationship between therapist countertransference management ability and therapy outcome was examined. Participants were 32 therapist‐trainees and their clinical supervisors. Supervisors completed the Countertransference Factors Inventory (CFI) with regard to their supervisees. The CFI assesses five therapist characteristics thought to comprise countertransference management: Self‐Insight, Self‐Integration, Anxiety Management, Empathy, and Conceptualizing Skills. Both trainees and their supervisors rated the degree of improvement for each client seen in therapy. Results indicated that the CFI total score and the subscales of Anxiety Management and Conceptualizing Skills were positively related to both trainee and supervisor ratings of outcome; Self‐Integration was related to trainee, but not supervisor, outcome ratings. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 861‐867, 2002.
Patterns of substance use in treatment‐seeking problem gamblers: Impact on treatment outcomes
Authors: Toneatto Tony , Skinner Wayne , Dragonetti Rosa
Published: October 2002

Accumulating evidence suggests that treatment‐seeking problem gamblers have high rates of substance abuse. However, relatively little is known about the relation between gambling problems and specific psychoactive substances apart from alcohol and methadone‐treated opiate addicts. In this study of 169 individuals seeking outpatient treatment for problem gambling, lifetime drug use and medication use were very high. Approximately half of the sample were using a psychiatric medication at the time they sought gambling treatment while very few individuals were using other drugs. Gambling treatment outcomes were unrelated to history of drug or medication use. No evidence was found for substitution of psychoactive substance use for gambling during the follow‐up year. These findings indicate that gamblers are more likely to be involved with drug and medication use compared to the general population, but that such histories are not associated with gambling treatment outcomes. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 853‐859, 2002.
Induction or suppression of expression of cytochrome C oxidase subunit II by heregulin β 1 in human mammary epithelial cells is dependent on the levels of ErbB2 expression
Authors: Sun Yanbo , Lin Hong , Zhu Yunfeng , Ma Cuiling , Ye Jianping , Luo Jia
Published: October 2002

The ErbB family of receptor kinases is composed of four members: epidermal growth factor receptor (EGFR/ErbB1), ErbB2/neu, ErbB3, and ErbB4. Amplification of the ErbB2/neu is found in about 30% of breast cancer patients and is associated with a poor prognosis. Heregulin (HRG) activates the ErbB2 via induction of heterodimerization with ErbB3 and ErbB4 receptors. With suppression subtractive hybridization, we demonstrated that the expression of cytochrome c oxidase subunit II (COXII) is HRG‐responsive. Two nontransformed human mammary epithelial cell lines, the HB2 and the HB2ErbB2 (the HB2 engineered to overexpress ErbB2), displayed an opposite response to HRG‐mediated regulation. HRG upregulated mRNA expression of COXII in the HB2 cells, but suppressed COXII expression in the HB2ErbB2 cells. A human breast cancer cell line (T47D), which expresses ErbB2 at a level similar to that of the HB2 cells, also responded to HRG by increasing COXII mRNA levels. Therefore, HRG regulation of COXII expression depends on the levels of ErbB2 expression. Furthermore, the expression of COXII was inversely correlated to the levels of ErbB2, i.e., the cells overexpressing ErbB2 exhibited lower COXII levels. HRG‐evoked signal transduction differed between the cells with normal ErbB expression and the cells overexpressing ErbB2. The activation of both ERK and PI3‐K was essential for HRG regulation of COXII, i.e., blockage of either pathway eliminated HRG‐mediated alteration. This is the first report demonstrating that the expression of mitochondria‐encoded COXII is HRG‐responsive. The levels of ErbB2 expression are decisive for the diverse biological activities of HRG. © 2002 Wiley‐Liss, Inc.
Infiltration anesthetic lidocaine inhibits cancer cell invasion by modulating ectodomain shedding of heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF)
Authors: Mammoto Tadanori , Higashiyama Shigeki , Mukai Mutsuko , Mammoto Akiko , Ayaki Masako , Mashimo Takashi , Hayashi Yukio , Kishi Yoshihiko , Nakamura Hiroyuki , Akedo Hitoshi
Published: October 2002

Although the mechanism is unknown, infiltration anesthetics are believed to have membrane‐stabilizing action. We report here that such a most commonly used anesthetic, lidocaine, effectively inhibited the invasive ability of human cancer (HT1080, HOS, and RPMI‐7951) cells at concentrations used in surgical operations (5–20 mM). Ectodomain shedding of heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF) from the cell surface plays an important role in invasion by HT1080 cells. Lidocaine reduced the invasion ability of these cells by partly inhibiting the shedding of HB‐EGF from the cell surface and modulation of intracellular Ca2+ concentration contributed to this action. The anesthetic action of lidocaine (sodium channel blocking ability) did not contribute to this anti‐invasive action. In addition, lidocaine (5–30 mM), infiltrated around the inoculation site, inhibited pulmonary metastases of murine osteosarcoma (LM 8) cells in vivo. These data point to previously unrecognized beneficial actions of lidocaine and suggest that lidocaine might be an ideal infiltration anesthetic for surgical cancer operations. © 2002 Wiley‐Liss, Inc.
Sonographically guided hydrostatic reduction of intussusception in children
Authors: Crystal Pavel , Hertzanu Yancu , Farber Boris , Shabshin Noga , Barki Yehiel
Published: October 2002

Purpose.

The aim of this study was to assess the efficacy of sonographically guided hydrostatic enema in therapeutic reduction of intussusception in children and to determine whether certain factors may predict the outcome of this technique.

Methods.

We retrospectively reviewed the medical records and sonographic examinations of 83 consecutive children sonographically diagnosed with 101 cases of intussusception over a 40‐month period. In 99 cases, sonographically guided hydrostatic reduction was attempted. The presence of free peritoneal fluid, the presence of fluid inside the intussusception, and the initial location of the intussusception, as confirmed by sonography, along with the level of experience of the radiologist who performed the reduction were statistically analyzed to determine their effect on outcome. A p value less than 0.05 was considered significant.

Results.

In 88 (89%) of the 99 cases, hydrostatic reduction was successful. No complications during or after hydrostatic enema were noted. The success rate was significantly lower among patients whose intussusception was located in the left side of the abdomen (p < 0.01) or contained entrapped fluid (p < 0.02) or those in whom hydrostatic reduction was not performed by an experienced sonologist (p < 0.01). The presence of free peritoneal fluid was not a predictor of outcome (p > 0.1). No complications during or after hydrostatic enema were noted.

Conclusions.

Sonographically guided hydrostatic reduction of intussusception is safe and effective. We recommend that this method be attempted before surgery is considered, even in cases in which the intussusception contains entrapped fluid or is located in the left side of the abdomen. The level of experience of the radiologist who performs the reduction significantly affects the results of this procedure and should be carefully considered, particularly in cases in which initial sonography reveals the presence of risk factors. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30: 343–348, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.10085
Adrenergic regulation of bone metabolism: Possible involvement of sympathetic innervation of osteoblastic and osteoclastic cells
Authors: Togari Akifumi
Published: October 2002

It has been demonstrated that human osteoblastic as well as osteoclastic cells are equipped with adrenergic receptors and neuropeptide receptors and that they constitutively express diffusible axon guidance molecules that are known to function as a chemoattractant and/or chemorepellent for growing nerve fibers. These findings suggest that the extension of axons of sympathetic and peripheral sensory neurons to osteoblastic and osteoclastic cells is required for the dynamic neural regulation of local bone metabolism. Recently, bone resorption modulated by sympathetic stimulation was demonstrated to be associated with ODF (osteoclast differentiation factor) and OCIF (osteoclastogenesis inhibitory factor) produced by osteoblasts/stromal cells. This review summarizes the evidence implicating sympathetic neuron action in bone metabolism. The possible function of osteoclastogenesis, which could result in the initiation of sympathomimetic bone resorption, is also discussed. Microsc. Res. Tech. 58:77–84, 2002. © 2002 Wiley‐Liss, Inc.
Apoptosis in the mature and developing olfactory neuroepithelium
Authors: Cowan Catherine M. , Roskams A. Jane
Published: October 2002

Neuronal apoptosis is important in the developmental sculpting of a normal nervous system and also in the loss of neurons caused by neurodegenerative disease, ischemia or trauma. In a developing embryo, exquisite mechanisms of regulation exist to balance factors that control neuronal birth and death within a given neuronal group, so that sufficient neurons develop and survive to elicit normal function. Postnatally, the only part of the mammalian nervous system where many of these regulatory balance mechanisms are retained is the olfactory epithelium (OE). During the last 30 years, researchers investigating olfactory receptor neuron cellular and developmental biology have focussed on the regeneration of the neuronal population within the olfactory neuroepithelium, following the induced death of the mature neuronal population. This body of work has thus far overshadowed the equally important and intrinsically linked phenomenon of the death of mature olfactory receptor neurons, which is required to initiate regeneration. The purpose of this review is to reveal what has been established about the different forms of cell death that can occur in neurons of the olfactory epithelium, and highlight the identified pro‐ and anti‐apoptotic pathways that control the normal and induced turnover of olfactory receptor neurons. Microsc. Res. Tech. 58:204–215, 2002. © 2002 Wiley‐Liss, Inc.
Pheromone detection by mammalian vomeronasal neurons
Authors: Zufall Frank , Kelliher Kevin R. , Leinders‐Zufall Trese
Published: October 2002

The vomeronasal organ (VNO) of mammals plays an essential role in the perception of chemical stimuli of social nature including pheromone‐like signals but direct evidence for the transduction of pheromones by vomeronasal sensory neurons has been lacking. The recent development of electrophysiological and optical imaging methods using confocal microscopy has enabled researchers to systematically analyze sensory responses in large populations of mouse vomeronasal neurons. These experiments revealed that vomeronasal neurons are surprisingly sensitive and highly discriminative detectors of volatile, urinary metabolites that have pheromonal activity in recipient mice. Functional mapping studies of pheromone receptor activation have uncovered the basic principles of sensory processing by vomeronasal neurons and revealed striking differences in the neural mechanisms by which chemosensory information is detected by receptor neurons in the VNO and the main olfactory epithelium. These advances offer the opportunity to decipher the logic of mammalian pheromonal communication. Microsc. Res. Tech. 58:251–260, 2002. © 2002 Wiley‐Liss, Inc.
Mechanical performance and glycolytic requirement in trout ventricular muscle
Authors: Gesser Hans
Published: October 2002

The glycolytic pathway seems to be coupled to the aerobic performance in mammalian cardiac muscle. Because many conditions are different in ectotherms, its influence on twitch force and resting force was recorded at 15°C in isometric ventricular preparations from rainbow trout. To reduce glycolytic activity, preparations were exposed to 0.4 mmol l−1 iodoacetate for 35 min or alternatively to 120 min anoxia in a glucose‐free solution containing 10 μmol l−1 adrenaline in an attempt to remove glycolytic substrates. The anoxic period was followed by recovery in an oxygenated solution containing aerobic substrates but no glucose. Control experiments indicated that this treatment, like iodoacetate, inhibits glycolysis, although glycogen was reduced by one half only. In fully oxygenated preparations with access to mitochondrial substrates, both attempts to reduce glycolytic activity tended to increase both resting force and the reductions in twitch force during high activity imposed by high stimulation rates and exposure to 10 μmol l−1 adrenaline. Thus, the glycolytic pathway appears to be of specific importance under aerobic conditions also in the heart of ectotherms. J. Exp. Zool. 293:360–367, 2002. © 2002 Wiley‐Liss, Inc.
Improved synthesis of 13C,2H3‐ and 2H3‐salmeterol by Cs2CO3‐mediated monoalkylation of a primary amine
Authors: Molinski Tadeusz F. , Stanley Scott D.
Published: October 2002

An abbreviated synthesis of isotopically labelled salmeterol has been achieved. The key improvement utilizes a highly selective Cs2CO3‐mediated one‐pot alkylation of benzylamine by 6‐bromo‐1‐(4′‐phenylbutoxy)hexane to prepare the limiting reagent, 6‐N‐benzylamino‐1‐(4′‐phenylbutoxy)hexane without overalkylation. The method was applied to synthesis of the title compounds in >97 at% isotopic purity. Copyright © 2002 John Wiley & Sons, Ltd.
Architecture of the integument in lower teleostomes: Functional morphology and evolutionary implications
Authors: Gemballa Sven , Bartsch Peter
Published: October 2002

A bony ganoid squamation is the plesiomorphic type in actinopterygians. During evolution, it was replaced by weak and more flexible elasmoid scales. We provide a comparative description of the integument of “ganoid” fishes and “nonganoid” fishes that considers all dermal components of mechanical significance (stratum compactum, morphology of ganoid scales, and their regional differences) in order to develop a functional understanding of the ganoid integument as a whole. Data were obtained for the extant “ganoid” fishes (Polypteridae and Lepisosteidae) and for closely related “lower” actinopterygians (Acipenser ruthenus, Amia calva) and “lower” sarcopterygians (Latimeria chalumnae, Neoceratodus forsteri). Body curvatures during steady undulatory locomotion, sharp turns, prey‐strikes, and fast starts in “ganoid” fishes were measured from videotapes. Extreme body curvatures as measured in anesthetized specimens are never reached during steady swimming, but are sometimes closely approached in certain situations (sharp turns, prey‐strike). During extreme body curvatures we measured high values of lateral strain on the convex and on the concave side of the body. Scale overlap changes considerably (66–127% in Lepisosteus, 42–140% in Polypterus). The ganoid squamation forms a protective coat, but at the same time it permits extreme body curvatures. This is reflected in characteristic morphological features of the ganoid scales, such as an anterior process, concave anterior margin, and peg‐and‐socket articulation. These characters are most pronounced in the anterior body region, where maximum changes in scale overlap are required. The anterior processes and anterior concave margin, together with the attached stratum compactum, guide movements in a horizontal plane during bending. Displacements of scales relative to each other are possible for scales of different scale rows, but are impeded in scales of the same scale row due to the peg‐and‐socket articulation. Furthermore, ganoid scale rows, fibers of collagen layers of the stratum compactum, and the lateral myoseptal structures follow the same oblique orientation, which is needed to achieve extreme body curvatures. There is no evidence that body curvatures are limited by the ganoid squamation in Polypterus or Lepisosteus to any larger extent than by a type of integument devoid of ganoid scales in teleostomes of similar body shape. Our results essentially contradict former functional interpretations: 1) Ganoid scales do not especially limit body curvature during steady undulatory locomotion; 2) They do not act as torsion‐resisting devices, but may be able to damp torsion together with the stratum compactum and internal body pressure. J. Morphol. 253:290–309, 2002. © 2002 Wiley‐Liss, Inc.
Pelvic and hindlimb musculature of Tyrannosaurus rex (Dinosauria: Theropoda)
Authors: Carrano Matthew T. , Hutchinson John R.
Published: October 2002

In this article, we develop a new reconstruction of the pelvic and hindlimb muscles of the large theropod dinosaur Tyrannosaurus rex. Our new reconstruction relies primarily on direct examination of both extant and fossil turtles, lepidosaurs, and archosaurs. These observations are placed into a phylogenetic context and data from extant taxa are used to constrain inferences concerning the soft‐tissue structures in T. rex. Using this extant phylogenetic bracket, we are able to offer well‐supported inferences concerning most of the hindlimb musculature in this taxon. We also refrain from making any inferences for certain muscles where the resulting optimizations are ambiguous. This reconstruction differs from several previous attempts and we evaluate these discrepancies. In addition to providing a new and more detailed understanding of the hindlimb morphology of T. rex—the largest known terrestrial biped—this reconstruction also helps to clarify the sequence of character‐state change along the line to extant birds. J. Morphol. 253:207–228, 2002. © 2002 Wiley‐Liss, Inc.
In the absence of rauber's sickle material, no blood islands are formed in the avian blastoderm
Authors: Callebaut Marc , Van Nueten Emmy , Bortier Hilde , Harrisson Fernand
Published: October 2002

Using the quail‐chick chimera technique, we followed the fate of Rauber's sickle cells in older whole blastoderms (cultured for approximately 2 days): after removal of the autochthonous Rauber's sickle from an unincubated chicken blastoderm, a quail Rauber's sickle was grafted isotopically and isochronically in its place. In transverse sections through these chimeras, the grafted quail Rauber's sickle cells were seen to have transformed into a broad row or ridge of quail junctional endoblast cells extending at the inner border of the area containing blood islands. After unilateral removal of the junctional endoblast from an intermediate streak chicken blastoderm (Stage 3; Hamburger and Hamilton [1951] J Morphol 88:49–92), we observed during further in vitro culture that at the operated side, in the area previously occupied by this junctional endoblast, blood islands no longer developed. If after such a unilateral removal of the chicken junctional endoblast quail junctional endoblast was apposed in its place, then blood islands reappeared in the operated area. The intimate contact between the apposed quail junctional endoblast and the recently formed blood islands, derived from peripherally migrating mesoderm, was very obvious on sections through such chimeras. We further demonstrate that Rauber's sickle vs. junctional endoblast is indispensable for the anlage of blood islands in avian blastoderms. Indeed, in the absence of Rauber's sickle material no blood islands develop (even when mesoderm is present after ingression of the upper layer via a primitive streak) in the isolated central region of the area centralis of unincubated chicken blastoderms after culture in vitro. Also, no junctional endoblast and no sickle canal appear in these explants. By contrast, if a Rauber's sickle fragment is placed on such an isolated central blastoderm region, then blood islands develop. These blood islands start to develop from peripherally migrating mesoderm in the neighborhood of the Rauber's sickle‐derived junctional endoblast. J. Morphol. 253:132–147, 2002. © 2002 Wiley‐Liss, Inc.
Gill‐derived glands in glandulocaudine fishes (teleostei: Characidae: Glandulocaudinae)
Authors: Bushmann Paul J. , Burns John R. , Weitzman Stanley H.
Published: October 2002

The Glandulocaudinae is a subfamily of neotropical characid fishes from Central and South America. A unifying feature of the subfamily is the caudal gland, found almost exclusively in males. The gland consists of tissue on the base of the caudal fin covered in part by hypertrophied scales. Scale movement as the caudal fin is flexed appears to facilitate the release of chemical compounds from the glandular tissue. We describe here a different structure, found in the gill cavity of mature males in 12 of 17 glandulocaudine genera examined. Termed a gill gland, it develops as a male secondary sex character and appears morphologically suited to release chemical signals. The gland forms by the growth of tissue over and around 4–13 anterior gill filaments on the first gill arch, forming chambers with ventral openings. Within the gland chambers, gill secondary lamellae usually shorten and may disappear. When secondary lamellae persist, simple columnar epithelial cells develop between them. In the absence of secondary lamellae, the gland chambers are lined with a simple cuboidal or columnar epithelium. Gland size and the degree of gill modification vary among species. Gill glands appear absent in five glandulocaudine genera, suggesting character reversals based on current phylogenetic hypotheses and systematic classification. Gill gland morphology suggests that this structure releases chemical compounds into the gill current. The presence of gill glands only in mature males suggests a function in reproduction and/or male aggression. Together with studies of the caudal gland, this research suggests that chemical signals may play important roles in glandulocaudine reproduction. J. Morphol. 253:187–195, 2002. © 2002 Wiley‐Liss, Inc.
Comparative structural connectivity spectra analysis (CoSCoSA) models of steroids binding to the aromatase enzyme
Authors: Beger Richard D. , Wilkes Jon G.
Published: October 2002

A method that combines NMR spectral and structural information into a constructed three‐dimensional (3D)‐connectivity matrix is developed for modeling biological binding activity of small molecules. The 3D‐connectivity matrix for a molecule is defined by associating the distances between all possible carbon‐to‐carbon connections with their assigned carbon NMR chemical shifts. In this project we selected from the total 3D‐connectivity matrix a subset, the two‐dimensional (2D) 13C‐13C COSY and a theoretical long range 2D 13C‐13C distance connectivity spectral plane. Patterns of 13C chemical shifts observed at these two relative distances for 50 steroids were used to produce a mathematical relationship for the steroids' relative binding affinity (pKi) to the aromatase enzyme. We call this technique comparative structural connectivity spectra analysis (CoSCoSA) modeling. Using combinations of the 2D COSY and 2D long‐range distance spectra as modeling parameters, we built four CoSCoSA models. One model was made from the 2D COSY spectra alone and another was developed using only the 2D long‐range distance spectra. Then the COSY and long‐distance spectra were combined in two different ways: starting with the combined principal components (PCs) from the separately calculated COSY and distance spectra or using the combined raw spectra (3D). The best CoSCoSA model was based on the combined PCs from COSY and distance spectra. This model had an r2 of 0.96 and a leave‐one‐out cross‐validation (q2) of 0.92. In general CoSCoSA modeling combines the quantum mechanical information inherent in NMR chemical shifts with internal molecular atom‐to‐atom distances to give a reliable and straightforward basis for predictive modeling. The technique has the flexibility and accuracy to outperform not only the cross‐validated variance q2 of previously published quantitative structure–activity relationships (QSAR) but also those obtained by related quantitative spectral data–activity relationships (QSDARs) lacking connectivity dimensions. Copyright © 2002 John Wiley & Sons, Ltd.
Comparison of first‐pass Gd‐DOTA and FAIRER MR perfusion imaging in a rabbit model of pulmonary embolism
Authors: Keilholz Shella D. , Mai Vu M. , Berr Stuart S. , Fujiwara Naomi , Hagspiel Klaus D.
Published: October 2002

Purpose

To compare the sensitivity of contrast‐enhanced magnetic resonance imaging (MRI) and arterial spin labeling to perfusion deficits in the lung.

Materials and Methods

A rabbit model of pulmonary embolism was imaged with both flow‐sensitive alternating inversion recovery with an extra radiofrequency pulse (FAIRER) arterial spin labeling and Gd‐DOTA enhanced MRI. The signal‐to‐noise ratio (SNR) was measured in the area of the perfusion deficit and the normal lung for both techniques.

Results

The defect was readily visible in all images. The normal lung had an average of 3.8 ± 1.2 times the SNR of the unperfused lung with the arterial spin labeling technique, and approximately 13.7 ± 3.3 times the SNR with the contrast‐enhanced technique.

Conclusion

Gd‐DOTA enhanced MRI provides higher SNR in pulmonary perfusion imaging; however, arterial spin labeling is also adequate and may be used when repeated studies are indicated. J. Magn. Reson. Imaging 2002;16:168–171. © 2002 Wiley‐Liss, Inc.
Epstein‐Barr virus and human immunodeficiency virus serological responses and viral burdens in HIV‐infected patients treated with HAART
Authors: O'Sullivan Cathal E. , Peng RongSheng , Cole Kelly Stefano , Montelaro Ronald C. , Sturgeon Timothy , Jenson Hal B. , Ling Paul D.
Published: October 2002

Epstein‐Barr virus (EBV) associated non‐Hodgkin lymphoma is recognized as a complication of human immunodeficiency virus (HIV) infection. Little is known regarding the influence of highly active antiretroviral therapy (HAART) on the biology of EBV in this population. To characterize the EBV‐ and HIV‐specific serological responses together with EBV DNA levels in a cohort of HIV‐infected adults treated with HAART, a study was conducted to compare EBV and HIV serologies and EBV DNA copy number (DNAemia) over a 12‐month period after the commencement of HAART. All patients were seropositive for EBV at baseline. Approximately 50% of patients had detectable EBV DNA at baseline, and 27/30 had detectable EBV DNA at some point over the follow‐up period of 1 year. Changes in EBV DNA copy number over time for any individual were unpredictable. Significant increases in the levels of Epstein‐Barr nuclear antigen (EBNA) and Epstein‐Barr early antigen (EA) antibodies were demonstrated in the 17 patients who had a good response to HAART. Of 29 patients with paired samples tested, four‐fold or greater increases in titers were detected for EA in 12/29 (41%), for EBNA in 7/29 (24%), for VCA‐IgG in 4/29 (14%); four‐fold decreases in titers were detected in 2/29 (7%) for EA and 12/29 (41%) for EBNA. A significant decline in the titer of anti‐HIV antibodies was also demonstrated. It was concluded that patients with advanced HIV infection who respond to HAART have an increase in their EBV specific antibodies and a decrease in their HIV‐specific antibodies. For the cohort overall, there was a transient increase in EBV DNA levels that had declined by 12 months. J. Med Virol. 67:320–326, 2002. © 2002 Wiley‐Liss, Inc.
Direct evidence for GB virus C/hepatitis G virus (GBV‐C/HGV) superinfection: Elimination of resident viral strain by donor strain in a patient undergoing liver transplantation
Authors: Fan Xiaofeng , Xu Yanjuan , Detre Katherine , Di Bisceglie Adrian M.
Published: October 2002

The viral genome of GB virus C/hepatitis G virus (GBV‐C/HGV), a single‐strand RNA virus, is subject to considerable variability and at least four genotypes have been suggested based on phylogenetic analysis. While co‐infection of GBV‐C/HGV with other infectious agents such as hepatitis C virus (HCV) has been frequently observed, there is no report whether or not co‐infection and/or superinfection occurs among different GBV‐C/HGV strains. By studying a GBV‐C/HGV positive recipient/donor pair in the context of undergoing liver transplantation, we have sequenced multiple clones derived from serum samples serially collected over four years. Detailed phylogenetic analyses have been performed with these sequences. The donor was infected with GBV‐C/HGV genotype 1 and this strain completely replaced recipient GBV‐C/HGV strain (genotype 2) after liver transplantation. The recipient's original viral strain became undetectable during follow‐up. Sequence analysis failed to identify genetic recombination between the two genotypes, at least in whole structural domain. This study, therefore, provides direct evidence for GBV‐C/HGV superinfection of one strain by another with one of them predominating probably due to replication competition. J. Med. Virol. 68:76–81, 2002. © 2002 Wiley‐Liss, Inc.
Sequence analysis of pre‐S/surface and pre‐core/core promoter genes of hepatitis B virus in chronic hepatitis C patients with occult HBV infection
Authors: Kao Jia‐Horng , Chen Pei‐Jer , Lai Ming‐Yang , Chen Ding‐Shinn
Published: October 2002

Although occult hepatitis B virus (HBV) infection in individuals without detectable hepatitis B surface antigen (HBsAg) may occur and has been reported to be common in patients with chronic hepatitis C, the related molecular mechanisms remain unknown. With the polymerase chain reaction, serum HBV DNA was sought in 100 HBsAg‐negative patients with chronic hepatitis C virus (HCV)‐infection. In those with occult HBV infection, possible genomic variability of HBV was evaluated by amplification and direct sequencing of pre‐S, surface, and pre‐core/core promoter genes. In total, 10 of the 100 patients (10%) had detectable serum HBV DNA, documenting an occult HBV infection. A deletion mutant in the pre‐S gene was found in one patient and mutations of the a determinant of HBsAg were observed in 2. In addition, a novel core promoter mutant (a dinucleotide substitution: T‐to‐C at nucleotide 1,802 and T‐to‐G at nucleotide 1,803, T1802C/T1803G) was found frequently in patients with occult HBV infection as compared to sex‐ and age‐matched HBsAg‐positive patients (80 vs. 10%, P < 0.001). In conclusion, the data suggest occult HBV infection is not uncommon in chronic hepatitis C patients in Taiwan, and a novel core promoter mutant may be associated with the absence of circulating HBsAg in these patients. J. Med. Virol. 68:216–220, 2002. © 2002 Wiley‐Liss, Inc.
A note on the thermal modelling of power semiconductor devices using the network analogue
Authors: Chung Wong Chi
Published: October 2002

The aim of this note is to point out that the boundary condition for the network modelling of thermal problems may have been incorrectly used in some previous studies. It is shown that the accuracy of the network analogue or the equivalent finite‐difference method is on the par with the finite‐element method for very fast transient thermal simulations. Copyright © 2002 John Wiley & Sons, Ltd.
Molecular mechanisms of enhanced susceptibility to apoptosis in differentiating oligodendrocytes
Authors: Osterhout D.J. , Marin‐Husstege M. , Abano P. , Casaccia‐Bonnefil P.
Published: October 2002

Several studies have shown that the progression of oligodendrocyte progenitors along the lineage correlates with increased susceptibility to death stimuli. The molecular basis of this phenomenon remains unclear. This study demonstrates that the protein levels of several proapoptotic molecules, including Bax, Bad (nonphosphorylated form), and certain caspase proforms, increase during oligodendrocyte development. In contrast, the steady‐state levels of antiapoptotic molecules, such as Bcl2 and BclXL, remain constant. This altered equilibrium between proapoptotic and antiapoptotic molecules correlates with increased cytochrome C in the cytosol. We conclude that, as oligodendrocytes mature, their susceptibility to apoptosis increases because of a change in the balance between protective mechanisms and proapoptotic pathways. This suggests the possible existence of a death susceptibility program, which is intrinsic to differentiating oligodendrocyte progenitors. © 2002 Wiley‐Liss, Inc.
Fractalkine and fractalkine receptors in human neurons and glial cells
Authors: Hatori Kozo , Nagai Atsushi , Heisel Rochelle , Ryu Jae K. , Kim Seung U.
Published: October 2002

Fractalkine has been identified as a novel chemokine that exhibits cell adhesion and chemoattractive properties in the central nervous system (CNS), and the fractalkine receptors, CX3CR1, are also expressed in the CNS. In the present study, the expression of fractalkine and fractalkine receptors was investigated in enriched populations of human CNS neurons, astrocytes, and microglia. In addition, the regulatory role played by protein kinase C (PKC) in fractalkine secretion in neurons was determined in A1 human hybrid neuronal cell line produced between a human cerebral neuron and a human neuroblastoma cell. Human neurons and astrocytes expressed fractalkine mRNA as determined by the revserse transcriptase‐polymerase chain reaction (RT‐PCR) analysis, while human microglia preparation did not express the fractalkine message. Human neurons and microglia expressed CX3CR1 mRNA, but astrocytes did not. These results suggest that fractalkine secreted by CNS neurons and astrocytes produce biological effects in neurons and microglia. Although phorbol ester did not change the expression of fractalkine mRNA level in A1 hybrid neurons, it did upregulate fractalkine secretion over unstimulated controls. This upregulation of fractalkine production was suppressed by the treatment with Ro32‐0432, a PKC inhibitor. These results indicate that intracellular signals transduced by PKC play an important role in the regulation of soluble fractalkine at the post‐transcriptional level in human neurons. As for the biological function of fractalkine, extracellularly applied fractalkine increased the number of bromodeoxyuridine‐labeled microglia 3‐fold over the untreated controls, indicating fractalkine induces proliferation of human microglia. These observations suggest that fractalkine released by injured neurons could induce proliferation, activation and/or migration of microglia at the injured brain sites. © 2002 Wiley‐Liss, Inc.
Cerebral postischemic reperfusion‐induced demethylation of the protein phosphatase 2A catalytic subunit
Authors: Martín de la Vega Cristina , Burda Jozef , Toledo Lobo M.V. , Salinas Matilde
Published: October 2002

Brain reperfusion after a period of global ischemia induces changes in the phosphorylation state of a great number of proteins. Neuronal responses to ischemia and reperfusion are quite different depending on the brain region, and phosphorylation changes may be implicated in this tissue‐specific response. For this reason, we have used both biochemical and immunohistochemical methods to investigate the potential role of PP2A, the most abundant Ser/Thr phosphatase in the brain, in ischemic injury. PP2A activity as measured with phosphorylase a as substrate was slightly inhibited after 30 min ischemia followed by 30 min reperfusion, and this inhibition correlated with an increased S6K1 and ERK1/2 phosphorylation. Using a monoclonal antibody unable to recognize the methylated form of PP2Ac, we demonstrated that the catalytic subunit of PP2A (PP2Ac) was highly methylated in the brain. In addition, the postischemic reperfusion‐induced changes in PP2Ac methylation were studied in sections from cerebral cortex, hippocampus and striatum. Regional differences in PP2Ac methylation were observed within control brains, and the postischemic reperfusion caused a generalized demethylation of PP2Ac. Those regions in the control brains containing highest levels of methylated PP2Ac were the most intensively demethylated after reperfusion and corresponded to the regions most vulnerable to ischemic damage. © 2002 Wiley‐Liss, Inc.
Differential lineage restriction of rat retinal progenitor cells in vitro and in vivo
Authors: Yang Peng , Seiler Magdalene J. , Aramant Robert B. , Whittemore Scott R.
Published: October 2002

To identify and characterize the lineage potential of rat neural retina progenitor cells (NRPCs) in vitro and engrafted into rats with retinal degeneration, NRPCs were isolated from neural retinas of embryonic day 17 Long Evans rats and cultured in serum‐free or serum‐containing media with fibroblast growth factor 2 and neurotrophin 3. After expansion, cellular differentiation was initiated by the withdrawal of these growth factors. Despite forming primary neurospheres, NRPCs cultured in serum‐free medium survived poorly after passage. In contrast, NRPCs cultured in serum‐containing medium could be expanded for up to 12 passages and differentiated into glial fibrillary acidic protein‐positive glial cells and retina‐specific neurons expressing rhodopsin, S‐antigen, calbindin, recoverin, and calretinin. For in vivo analysis, passage 1 (P1) undifferentiated NRPCs were labeled with bromodeoxyuridine (BrdU), implanted into the subretinal space of Royal College of Surgeons (RCS) rats, and analyzed immunohistochemically 4 weeks postgrafting. The grafted NRPCs showed extensive glial differentiation, irrespective of their topographic localization. A few BrdU‐labeled grafted NRPCs expressed protein kinase C, a marker for bipolar and amacrine interneuron‐specific differentiation. Other retina‐specific or oligodendrocytic differentiation was not detected in the grafted cells. Although NRPCs are capable of self‐renewal and multilineage differentiation in vitro, they developed mostly into glial cells following engraftment into the adult retina. These data suggest that the adult retina retains epigenetic signals that are either restrictive for neuronal differentiation or instructive for glial differentiation. Induction of lineage‐specific cell differentiation of engrafted NRPCs to facilitate retinal repair will likely require initiation of specific differentiation in vitro prior to grafting and/or modification of the host environment concomitantly with NRPC grafting. © 2002 Wiley‐Liss, Inc.
Self‐esteem, appraisal and coping: a comparison of unemployed and re‐employed people
Authors: Waters Lea E. , Moore Kathleen A.
Published: October 2002

The negative effects of unemployment on psychological health are well documented, yet Kasl's (1982) reverse causation hypothesis is that positive psychological health, and in particular self‐esteem, facilitates re‐employment. The aim of this study was to investigate this proposal by assessing levels of self‐esteem, cognitive appraisals and coping efforts among unemployed persons and relating these factors to their employment status six months later. Two hundred and one unemployed (49 per cent female, 51 per cent male; mean age = 32.41 ± 10.18 years) and 128 employed respondents (59 per cent female, 41 per cent male; mean age = 35.0 ± 11.73 years) participated in the study. Participants completed the Adult Self‐Perception Profile, Access to Categories of Experience, Locus of Control, Deakin Coping Scale, and the Meaningful Leisure Activities Questionnaire at baseline and at six‐month follow‐up using a mail‐out survey. Comparison of baseline appraisals revealed that future re‐employed participants rated their latent deprivation lower and their internal locus of control higher than those continuously unemployed, and they also derived more internal meaning from leisure activities. Overall, the results provide support for Kasl's reverse causation hypothesis extended to these other domains of psychological health. Intervention strategies designed to incorporate the promotion of these factors are discussed. Copyright © 2002 John Wiley & Sons, Ltd.