bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epidermal differentiation during ontogeny and after hatching in the snake Liasis fuscus (Pythonidae, Serpentes, Reptilia), with emphasis on the formation of the shedding complex
Authors: Alibardi L. , Thompson M.B. 
Published: March 2003

AbstractDifferentiation and localization of keratin in the epidermis during embryonic development and up to 3 months posthatching in the Australian water python, Liasis fuscus, was studied by ultrastructural and immunocytochemical methods. Scales arise from dome‐like folds in the skin that produce tightly imbricating scales. The dermis of these scales is completely differentiated before any epidermal differentiation begins, with a loose dermis made of mesenchymal cells beneath the differentiating outer scale surface. At this stage (33) the embryo is still unpigmented and two layers of suprabasal cells contain abundant glycogen. At Stage 34 (beginning of pigmentation) the first layers of cells beneath the bilayered periderm (presumptive clear and oberhautchen layers) have not yet formed a shedding complex, within which prehatching shedding takes place. At Stage 35 the shedding complex, consisting of the clear and oberhautchen layers, is discernible. The clear layer contains a fine fibrous network that faces the underlying oberhautchen, where the spinulae initially contain a core of fibrous material and small beta‐keratin packets. Differentiation continues at Stage 36 when the beta‐layer forms and beta‐keratin packets are deposited both on the fibrous core of the oberhautchen and within beta‐cells. Mesos cells are produced from the germinal layer but remain undifferentiated. At Stage 37, before hatching, the beta‐layer is compact, the mesos layer contains mesos granules, and cells of the alpha‐layer are present but are not yet keratinized. They are still only partially differentiated a few hours after hatching, when a new shedding complex is forming underneath. Using antibodies against chick scale beta‐keratin resolved at high magnification with immunofluorescent or immunogold conjugates, we offer the first molecular confirmation that in snakes only the oberhautchen component of the shedding complex and the underlying beta cells contain beta‐keratin. Initially, there is little immunoreactivity in the small beta‐packets of the oberhautchen, but it increases after fusion with the underlying cells to produce the syncytial beta layer. The beta‐keratin packets coalesce with the tonofilaments, including those attached to desmosomes, which rapidly disappear in both oberhautchen and beta‐cells as differentiation progresses. The labeling is low to absent in forming mesos‐cells beneath the beta‐layer. This study further supports the hypothesis that the shedding complex in lepidosaurian reptiles evolved after there was a segregation between alpha‐keratogenic cells from beta‐keratogenic cells during epidermal renewal. J. Morphol. 256:29–41, 2003. © 2003 Wiley‐Liss, Inc.
Autapomorphies of the endophragmal system in trichodactylid freshwater crabs (Crustacea: Decapoda: Eubrachyura)
Authors: Sternberg Richard v. , Cumberlidge Neil 
Published: March 2003

AbstractAn examination of the thoracic endophragmal system in trichodactylid freshwater crabs revealed several derived features that appear restricted to this family. Trichodactylids have a highly reduced sella turcica with a rim‐like overall configuration; as a consequence of sella turcica reduction the median septum is dorsoventrally diminished and exposed along its length. In addition, interosternite 7/8 is medially erased with the remnants restricted to the lateral regions of the sternum. The configurations of the sella turcica and interosternite 7/8 in trichodactylids underscore the monophyly of this family. The Dilocarcininae is characterized by having interosternites 5/6 through 7/8 restricted to the lateral sectors of the sternum, the lateral remnants of interosternite 4/5 forming prominent, rib‐like ridges oriented diagonally to the longitudinal axis of the crab, and the median septum forming with interosternite 4/5 a Y‐shaped pattern. These autapomorphies of the endophragmal system separate the trichodactylids from all other eubrachyurans and emphasize the morphological distinctness of the group. A description of the trichodactylid endophragmal junction plate is also provided. J. Morphol. 256:23–28, 2003. © 2003 Wiley‐Liss, Inc.
Anatomical features of Leiopelma embryos and larvae: Implications for anuran evolution
Authors: Bell Ben D. , Wassersug Richard J. 
Published: March 2003

AbstractA controversial issue in anuran systematics is the relationship of Leiopelma to other anurans because recent phylogenetic constructions imply different relationships among the basal frogs. Of particular evolutionary interest is whether early development of Leiopelma resembles an ancestral salamander‐like larva, an anuran tadpole, or neither. In the 1950s, Neville G. Stephenson hypothesized that direct development is the primary mode of development in amphibians, based on the fact that Leiopelma spp. lack a free‐living (=feeding) larval stage. Although this hypothesis has not been generally accepted, it has not been formally refuted. We review Stephenson's work on Leiopelma and examine the anatomy of embryos/“larvae” of the four extant Leiopelma species for evidence of vestigial larval features that might refute the “direct‐developing ancestor” hypothesis. We describe internal oral features in early developmental stages of Leiopelma and compare Leiopelma with a closely related basal anuran, Ascaphus, to assess whether their early developmental stages share any derived features. In Leiopelma hochstetteri, embryos/larvae have open gill slits and some faint rugosities around one gill slit that may be vestiges of gill rakers or filters. They also have more intestinal loops, indicative of an elongated alimentary tract, at earlier rather than late embryonic/larval stages. Collectively, these features support the view that the ancestor of Leiopelma had a free‐swimming, free‐feeding, aquatic larva. The palatoquadrate of Leiopelma archeyi reorients approximately 40° from a more horizontal to a more vertical position through embryonic/“larval” development. This amount of cranial remodeling is intermediate between that seen in salamanders (17–27°) and that reported for Ascaphus (64°) and other basal frogs (71–78°) at metamorphosis. We found no internal oral features that Leiopelma shares specifically with Ascaphus. However, Leiopelma embryos have a ventrally positioned mouth and a downturned rostrum, characteristic of Ascaphus and other stream‐adapted tadpoles. J. Morphol. 256:160–170, 2003. © 2003 Wiley‐Liss, Inc.
Mutational patterns of paired blood and rectal biopsies in HIV‐infected patients on HAART
Authors: Monno Laura , Punzi Grazia , Scarabaggio Teresa , Saracino Annalisa , Brindicci Gaetano , Fiore José Ramon , Caputi Iambrenghi Onofrio , Di Stefano Mariantonietta , Pastore Giuseppe , Angarano Gioacchino 
Published: March 2003

AbstractBlood and concurrent rectal biopsy samples of human immunodeficiency virus type 1 (HIV‐1)‐positive highly active antiretroviral therapy (HAART)‐treated patients were tested for genotypic resistance by direct sequencing of reverse transcriptase (RT) and protease (PR) regions to compare the patterns of resistance in these compartments. Fourteen subjects (five with undetectable plasma viral load (pVL) and nine persistently viremic) were studied. Four of five patients with undetectable pVL also had undetectable mucosal HIV RNA; sequence analyses from proviral DNA (PBMCs and rectal biopsy) were obtained with none or few resistance‐associated mutations and no alteration of susceptibility profile. All viremic patients, and one with negative pVL, had detectable levels of mucosal HIV RNA (1.93–4.21 log10 copies/mg); sequences of HIV RNA (plasma and/or rectal biopsy) were also obtained, and multiple mutations generally compatible with current/past medications were detected. Overall, 40 HIV‐1 PR and 42 RT sequences were analyzed, yielding a total of 42 PR and 47 RT sequence pairs (plasma/tissue‐RNA; plasma‐RNA/tissue‐DNA; PBMC/tissue‐DNA; tissue‐DNA/RNA; tissue‐RNA/PBMC‐DNA; PBMC‐DNA/plasma‐RNA), which almost always differed at the total amino acid level (median percentage discordance 8.08% in the PR, 4.8% in RT). The median percentage of resistance position discordance equaled 88.8% (IQR = 20–100) in the PR and 74.55% (IQR = 31.75–100%) in the RT pairs, respectively. Different resistance levels were detected by means of a computer‐assisted interpretation of mutational profiles. The results support the multiform evolution of HIV genotype in various body compartments and emphasize the participation of intestinal mucosa in HIV genotype selection. Samples from diverse tissues should be used for resistance evaluation to obtain a complete picture of drug resistance for antiretroviral‐treated patients. J. Med. Virol. 70: 1–9, 2003. © 2003 Wiley‐Liss, Inc.
Elevated levels of total and dengue virus‐specific immunoglobulin E in patients with varying disease severity
Authors: Koraka Penelopie , Murgue Bernadette , Deparis Xavier , Setiati Tatty E. , Suharti Catarina , van Gorp Eric C.M. , Hack C.E. , Osterhaus Albert D.M.E , Groen Jan 
Published: March 2003

AbstractThe kinetics of total and dengue virus‐specific immunoglobulin E (IgE) were studied in serial serum samples obtained from 168 patients, 41 of whom suffered from primary dengue virus infection and 127 suffered from secondary dengue virus infection. Seventy‐one patients were classified as dengue fever, 30 as dengue hemorrhagic fever, and 67 as dengue shock syndrome. A control group included single serum samples from patients with a herpes virus infection (n = 14), non‐dengue febrile patients (n = 10), and healthy blood donors (n = 10). Patients with dengue virus infection had higher levels of total and dengue virus‐specific IgE than non‐dengue patients (P < 0.05). Patients with secondary dengue virus infections had not significantly increased levels of both total and dengue virus‐specific IgE in the acute phase of disease compared to patients with primary dengue virus infections. Dengue virus‐specific IgE was significantly higher in dengue hemorrhagic fever and/or dengue shock syndrome patients compared to dengue fever and non‐dengue patients (P < 0.05). In conclusion, this study showed elevated total and dengue virus‐specific IgE serum antibody levels in the acute stage of disease. Therefore, measurement of both total and dengue virus‐specific IgE serum antibodies can be used as an additional prognostic marker in the development of severe complications in dengue virus infections. In addition, the presence and increase of dengue virus‐specific IgE serum antibodies in patients with dengue virus infections is suggestive of the pathogenetic role that IgE may play in the hemostatic disorders observed in dengue hemorrhagic fever and dengue shock syndrome. J. Med. Virol. 70:91–98, 2003. © 2003 Wiley‐Liss, Inc.
Recombinant murine L20B cell line supports multiplication of group A coxsackieviruses
Authors: Nadkarni Sushma S. , Deshpande Jagadish M. 
Published: March 2003

AbstractSensitive, reliable, and rapid methods of virus culture are essential for wild poliovirus isolation and identification from stool specimens collected from cases of acute flaccid paralysis. Recently, recombinant murine cell lines expressing human poliovirus receptor (CD155) on the cell surface have become available. These cells are sensitive selectively to poliovirus because the poliovirus receptor is not used by other enteroviruses. In early field studies non‐polio enteroviruses were not isolated from stool samples of cases of acute flaccid paralysis using L20B cells. For the past 3 years, L20B cells were used extensively in our laboratory for virus culture. The objective of the present study was to identify non‐polio enteroviruses causing cytopathic changes in L20B cells. Stool specimens collected from 1,153 cases of acute flaccid paralysis and 2,670 apparently healthy children were tested for enteroviruses using RD and L20B cell lines. A small number of viruses other than poliovirus causing cytopathic effect in L20B cells were isolated. Such isolates detected in other polio network laboratories in India were also included. The virus isolates were typed using partial VP1 nucleotide sequence analysis and virus neutralization tests. Of the 111 viruses studied, 8 were non‐enteroviruses. Among the 103 non‐polio enteroviruses, 73 were identified as group A coxsackieviruses. Of the 30 isolates that could not be characterized, 1 remained unidentified even by sequence analysis and 29 did not reach high titers in L20B as well as RD cells. In conclusion, coxsackie A viruses multiply in L20B cells causing cytopathic effect. Coxsackievirus A8 and coxsackievirus A10 were predominant among the eight coxsackie A virus types so far identified. J. Med. Virol. 70:81–85, 2003. © 2003 Wiley‐Liss, Inc.
Inhibition of enterovirus 71‐induced apoptosis by allophycocyanin isolated from a blue‐green alga spirulina platensis
Authors: Shih Shin‐Ru , Tsai Kun‐Nan , Li Yi‐Shuane , Chueh Chuang‐Chun , Chan Err‐Cheng 
Published: March 2003

AbstractEnterovirus 71 infection causes significant morbidity and mortality in children, yet there is no effective treatment. In this study, a protein‐bound pigment, allophycocyanin purified from blue‐green algae is first reported to exhibit anti‐enterovirus 71 activity. Allophycocyanin neutralized the enterovirus 71‐induced cytopathic effect in both human rhabdomyosarcoma cells and African green monkey kidney cells. The 50% inhibitory concentration of allophycocyanin for neutralizing the enterovirus 71‐induced cytopathic effect was approximately 0.045 ± 0.012 μM in green monkey kidney cells. The cytotoxic concentrations of allophycocyanin for rhabdomyosarcoma cells and African green monkey kidney cells were 1.653 ± 0.003 μM and 1.521 ± 0.012 μM, respectively. A plaque reduction assay showed that the concentrations of allophycocyanin for reducing plaque formation by 50% were approximately 0.056 ± 0.007 μM and 0.101 ± 0.032 μM, when allophycocyanin were added at the state of viral adsorption and post‐adsorption, respectively. Antiviral activity was more efficient in cultures treated with allophycocyanin before viral infection compared with that in the cultures treated after infection. Allophycocyanin was also able to delay viral RNA synthesis in the infected cells and to abate the apoptotic process in enterovirus 71‐infected rhabdomyosarcoma cells with evidence of characteristic DNA fragmentation, decreasing membrane damage and declining cell sub‐G1 phase. It is concluded that allophycocyanin possesses antiviral activity and has a potential for development as an anti‐enterovirus 71 agent. J. Med. Virol. 70:119–125, 2003. © 2003 Wiley‐Liss, Inc.
Introduction of HIV type 1 non‐B subtypes into Eastern Andalusia through immigration
Authors: Alvarez Marta , García Federico , Martínez Nora Mariela , García Fernando , Bernal Carmen , Vela Carmen Maroto , Angulo Gonzalo Piédrola , Quero José Hernández 
Published: March 2003

AbstractA study of the distribution of HIV‐1 subtypes in the native and immigrant populations of Eastern Andalusia (Southern Spain) was conducted to determine any changes between 1983 and 2001 and to identify antiretroviral resistance mutations in non‐B subtype strains among the immigrant population. The study included 111 native patients from Eastern Andalusia: 94 infected with HIV before 1996 and 17 infected since 1996. A parallel study was conducted on 26 HIV‐positive immigrants from Africa. Subtyping was done with the heteroduplex mobility assay. Resistance mutations were determined by line probe assay. A total of 137 patients were studied: 9.2% had subtype A (n = 12), 80.8% subtype B (n = 105), and 1.5% subtype C (n = 2). Among the Eastern Andalusia population infected before 1996, 10.9% had non‐B subtypes, compared with 23.5% of those infected after that year. The greatest percentage of non‐B subtypes (52.4%) was found among the immigrant population. Resistance mutation K70R was detected in one of the six immigrants with non‐B subtype and M41L in another. There has been a slight increase in the diversity of HIV‐1 subtypes in Eastern Andalusia over the past few years, possibly influenced by non‐B subtypes introduced by immigrants from sub‐Saharan Africa. J. Med. Virol. 70: 10–13, 2003. © 2003 Wiley‐Liss, Inc.
Epstein‐barr virus infection of rat lymphocytes expressing human CD21 results in restricted latent viral gene expression and not in immunoblastic transformation
Authors: Yang Lixin , Ikeda Hitoshi , Lai Yurong , Yoshiki Takashi , Takada Kenzo 
Published: March 2003

AbstractTransgenic rats expressing human CD21 gene (hCD21) driven by the mouse immunoglobulin enhancer were generated. hCD21 was expressed in lymphoid tissues, especially in the spleen and in the brain. Flow cytometric analysis indicated that about 20% of spleen cells, most having a B‐lymphocyte marker, expressed hCD21. After Epstein‐Barr virus (EBV) infection of spleen cells, EBV‐determined nuclear antigen (EBNA) was first detected on Day 4 and reached a maximum of 0.3% on Day 5, but the infection was abortive and was not followed by blastogenesis, cellular DNA synthesis or proliferation. Reverse transcription‐polymerase chain reaction (RT‐PCR) analyses demonstrated that EBV‐infected spleen cells expressed EBNA1 and EBV‐encoded small RNA (EBER), but not other latent EBV products. EBNA promoter analysis by RT‐PCR indicated that the Q promoter was active, whereas C and W promoters were not active. The present findings indicate that human and rat lymphocytes respond to EBV infection differently in vitro. J. Med. Virol. 70:126‐130, 2003. © 2003 Wiley‐Liss, Inc.
GB Virus C genotype determination in GB Virus‐C/HIV co‐infected individuals
Authors: Muerhoff A. Scott , Tillmann Hans L. , Manns Michael P. , Dawson George J. , Desai Suresh M. 
Published: March 2003

AbstractSeveral recent studies have indicated that patients infected with human immunodeficiency virus (HIV) exhibit a beneficial effect of co‐infection with GB virus C (GBV‐C). The benefit is demonstrated by slower progression to acquired immunodeficiency syndrome (AIDS) and prolonged survival time after the development of AIDS. In some but not all studies, a significant association between GBV‐C/HIV co‐infection and increased CD4+ cell counts has been reported. To understand further the possible role that GBV‐C might play in the reduced morbidity and mortality among HIV‐infected patients, we sought to examine the presence of different GBV‐C genotypes in a cohort of co‐infected patients. PCR products derived from the 5′‐untranslated region (5′‐UTR) and the second envelope gene (E2) were sequenced directly and genotyped by phylogenetic analysis. While 5′‐UTR analysis delineated the major type, analysis of the complete E2 gene was required for identification of group 2 subtypes, designated 2a and 2b. Among 35 patients tested, GBV‐C genotype was determined for 33: two patients were infected with genotype 1, 12 with type 2a, and 19 with type 2b. Clinical data were available for 25 genotyped patients: one infected with genotype 1, nine with genotype 2a, and 15 with type 2b. CD4 cell counts tended to be lower in patients infected with genotype 2a compared with those with genotype 2b (310 ± 136 vs 430 ± 199, P = 0.054). Additional studies with larger cohorts from separate geographical regions are needed to determine whether a particular GBV‐C genotype is associated with reduced morbidity or mortality among HIV co‐infected patients. J. Med. Virol. 70:141–149, 2003. © 2003 Wiley‐Liss, Inc.
Time‐domain simulation of the full hydrodynamic model
Authors: Aste Andreas , Vahldieck Rüdiger 
Published: March 2003

AbstractA simple upwind discretization of the highly coupled non‐linear differential equations which define the hydrodynamic model for semiconductors is given in full detail. The hydrodynamic model is able to describe inertia effects which play an increasing role in different fields of opto‐ and microelectronics. A silicon n+−n−n+‐structure is simulated, using the energy‐balance model and the full hydrodynamic model. Results for stationary cases are then compared, and it is pointed out where the energy‐balance model, which is implemented in most of today's commercial semiconductor device simulators, fails to describe accurately the electron dynamics. Additionally, a GaAs n+−n−n+‐structure is simulated in time domain in order to illustrate the importance of inertia effects at high frequencies in modern submicron devices. Copyright © 2003 John Wiley & Sons, Ltd.
Hydroxyl radical formation is greater in striatal core than in penumbra in a rat model of ischemic stroke
Authors: Liu Shimin , Liu Miao , Peterson Steven , Miyake Minoru , Vallyathan Val , Liu Ke Jian 
Published: March 2003

AbstractAlthough hydroxyl radical (•OH) formation has been implicated in the pathophysiological changes of ischemic stroke, •OH production in the core and penumbra regions is not clear. It is extremely important to distinguish penumbra from ischemic core in focal cerebral ischemia studies, because the penumbra contains viable tissue, which can be salvaged by appropriate treatment. This study evaluated •OH production in both core and penumbra regions of ischemic striatum during ischemia and reperfusion. Microdialysis probes were placed in striatal tissue of rats subjected to the middle cerebral artery occlusion model of ischemic stroke. The •OH‐trapping agent 4‐hydroxybenzoic acid (4‐HBA) was administered by both i.v. and probe infusion. Dialysate levels of the 4‐HBA oxidation products, 3,4‐dihydroxybenzoic acid (3,4‐DHBA), were determined by HPLC‐ECD. After microdialysis probe delivery of 4‐HBA, •OH production was significantly increased in the striatal core during both ischemia and reperfusion. Penumbra •OH production increased only during reperfusion. Alterations of 3,4‐DHBA concentration in dialysate following i.v. 4‐HBA administration were likely related to alterations in tissue blood flow. The findings were confirmed by a greater oxidation of dihydroethidium in the ischemic core than in the penumbra as determined by fluorescent microscopy. The findings of •OH production in ischemic striatum are the opposite of those reported for ischemic cortex and suggest critical regional variations in •OH production that may have significant clinical implications in the treatment of ischemic stroke. © 2003 Wiley‐Liss, Inc.
Neurotoxicity from glutathione depletion is dependent on extracellular trace copper
Authors: White Anthony R. , Cappai Roberto 
Published: March 2003

AbstractGlutathione (GSH) is an important antioxidant, and its depletion in neurons has been implicated in several neurodegenerative disorders. Aberrant copper metabolism is also implicated in neurodegeneration and may result in the generation of toxic free radicals. However, little is known about the relationship between GSH depletion and copper homeostasis. In the present study, we examined the role of extracellular trace biometals in neuronal cell death induced by GSH depletion. Treatment of primary cortical neurons with buthionine sulfoximine (BSO), an inhibitor of GSH synthesis, induced a rapid loss of intracellular GSH, leading to decreased neuronal cell viability. Neuronal cell death induced by GSH depletion was dependent on trace levels of extracellular copper in the culture medium (1.6 μM). Neurons were protected against GSH depletion‐mediated toxicity when cultured in Chelex 100‐treated medium containing tenfold less copper (0.16 μM) than normal medium. The addition of copper, but not iron or zinc, to Chelex 100‐treated medium restored the neurotoxicity induced by GSH depletion. Moreover, BSO toxicity in normal medium was inhibited by copper chelators. The neurotoxic effects of copper in GSH‐depleted neurons involved generation of copper(I) and subsequent free radical‐mediated oxidative stress. These studies demonstrate a critical role for extracellular trace copper in neuronal cell death caused by GSH depletion and may have important implications for the understanding of toxic processes in neurodegenerative diseases. © 2003 Wiley‐Liss, Inc.