bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of simulated microgravity on avian primordial germ cell migration and reproductive capacity
Authors: Li Zandong , Song Yonghong , Ma Yuzhong , Wei Hua , Liu Chunhai , Huang Jinsong , Wang Ning , Sha Jin , Sakurai Fujiro 
Published: August 2002

AbstractFertilized eggs of chicken and quail were incubated under the simulated microgravity condition provided by a clinostat. The number of Primordial Germ Cells (PGCs) was counted in early embryogenesis, and the reproductive capacity of quail hatched following the simulated microgravity was investigated .Simulated microgravity caused significant decline of PGCs in the blood of early chicken embryos and in the gonads. The numbers of spermatogonia in the hatchling testis were also fewer than those in the control groups. Therefore, simulated microgravity may retard gonadial development and reduce the reproductive capacity. J. Exp. Zool. 292:672–676, 2002. © 2002 Wiley‐Liss, Inc.
Search for genes involved in the temperature‐induced gonadal sex differentiation in the tilapia, Oreochromis niloticus
Authors: D’Cotta Helena , Fostier Alexis , Guiguen Yann , Govoroun Marina , Baroiller Jean‐François 
Published: August 2002

AbstractIn the tilapia, Oreochromis niloticus, sex is determined by genetic factors (XX/XY) but temperature can also influence the gonadal sex differentiation. Elevated temperatures of 35°C can generate functional male phenotypes if applied before and during sexual differentiation. The genes and mechanisms by which temperature acts on the cascade leading to sex differentiation have been investigated. Two strategies have been followed: 1) Search for novel genes by differential display, and 2) Expression studies of candidate genes. Genetically all‐female and all‐male progenies were reared at 27°C (natural temperature) and at 35°C (masculinizing treatment) and gonads dissected. Using differential display, we isolated a 300 bp cDNA (MM20C) from temperature‐masculinized females. Virtual northern analysis revealed a 1.2 kb transcript in 35°C treated females and males, but hardly any expression in natural females (27°C). Semi‐quantitative RT‐PCR established a several‐fold increase in MM20C expression in 35°C masculinized fry. Elevated expression was observed in natural males (27°C) with higher levels detected in those reared at 35°C. Furthermore, we have analyzed as a candidate gene the P450 11β‐hydroxylase, an important androgen steroidogenic enzyme. Low levels of expression were found in natural males. This coincides with low concentrations of 11 ketotestosterone in the gonads before and during gonadal sex differentiation. Higher expression levels of 11β‐hydroxylase were detected in male gonads at 35°C but levels in phenotypic males were similar to those found for natural females. Previous results reported that expression of aromatase is repressed by masculinizing treatments. Our study demonstrated that masculinizing‐temperature can also stimulate the expression of other gene(s). J. Exp. Zool. 290:574–585, 2001. © 2001 Wiley‐Liss, Inc.
Sex reversal and aromatase in chicken
Authors: Vaillant Severine , Dorizzi Mireille , Pieau Claude , Richard‐Mercier Noelle 
Published: August 2002

AbstractAromatase inhibitors administered before sexual differentiation of the gonads can induce sex reversal in female chickens. To analyze the process of sex reversal, we have followed for several months the changes induced by Fadrozole, a nonsteroidal aromatase inhibitor, in gonadal aromatase activity and in morphology and structure of the female genital system. Fadrozole was injected into eggs on day four of incubation, and its effects were examined during the embryonic development and for eight months after hatching.In control females, aromatase activity in the right and the left gonad was high in the middle third of embryonic development, and then decreased up to hatching. After hatching, aromatase activity increased in the left ovary, in particular during folliculogenesis, whereas in the right regressing gonad, it continued to decrease to reach testicular levels at one month.In treated females, masculinization of the genital system was characterized by the maintenance of the right gonad and its differentiation into a testis, and by the differentiation of the left gonad into an ovotestis or a testis; however, in all individuals, the left Müllerian duct and the posterior part of the right Müllerian duct were maintained. In testes and ovotestes, aromatase activity was lower than in gonads of control females (except in the right gonad as of one month after hatching) but remained higher than in testes of control and treated males. Moreover, in ovotestes, aromatase activity was higher in parts displaying follicles than in parts devoid of follicles. The main structural changes in the gonads during sex reversal were partial (in ovotestes) or complete (in testes) degeneration of the cortex in the left gonad, and formation of an albuginea and differentiation of testicular cords/tubes in the two gonads. Testicular cords/tubes transdifferentiated from ovarian medullary cords and lacunae whose epithelium thickened and became Sertolian. Transdifferentiation occurred all along embryonic and postnatal development; thus, new testicular cords/tubes were continuously formed while others degenerated. The sex reversed gonads were also characterized by an abundant fibrous interstitial tissue and abnormal medullary condensations of lymphoid‐like cells; in the persisting testicular cords/tubes, spermatogenesis was delayed and impaired. Related to aromatase activity, persistence of too high levels of estrogens can explain the presence of oviducts, gonadal abnormalities and infertility in sex reversed females. J. Exp. Zool. 290:727–740, 2001. © 2001 Wiley‐Liss, Inc.
Early development of amphioxus nervous system with special reference to segmental cell organization and putative sensory cell precursors: A study based on the expression of pan‐neuronal marker gene Hu/elav
Authors: Satoh Gouki , Wang Yong , Zhang Peijun , Satoh Nori 
Published: August 2002

AbstractThe development of the nervous system of amphioxus was investigated at the cellular level based on the expression of the pan‐neuronal marker gene Hu/elav. In situ hybridization analysis showed that an amphioxus Hu/elav homolog (AmphiHu/Hel) was expressed in individual cells within the neural plate, but the cells exhibited no obvious arrangements in early embryos without distinct somites. However, in neurulae with somites, AmphiHu/Hel‐positive cells were clustered along the D‐V axis in close register with the boundaries of somites, resulting in reiterated cell arrangements that became evident along the neuraxis. Furthermore, AmphiHu/Hel‐positive cell clusters appeared one by one along with the development of underlying somites. Double‐staining in situ hybridization analysis with the islet gene revealed that the cell clusters contain presumptive motoneurons. In addition, AmphiHu/Hel expression was also observed outside the CNS, probably in the epithelial ectoderm, suggesting that amphioxus has a large number of putative sensory cell precursors as early as the early neurula stage. Taking recent gene expression studies and anatomical studies into consideration, we discuss ontogenetic and phylogenetic features of the amphioxus nervous system. J. Exp. Zool. (Mol. Dev. Evol.) 291:354–364, 2001. © 2001 Wiley‐Liss, Inc.
The evolution of genome size: What can be learned from anuran development?
Authors: Chipman Ariel D. , Khaner Oded , Haas Alexander , Tchernov Eitan 
Published: August 2002

AbstractDifferences in nuclear DNA content in vertebrates have been shown to be correlated with cell size, cell division rate, and embryonic developmental rate. We compare seven species of anuran amphibians with a three‐fold range of genome sizes. Parameters examined include the number and density of cells in a number of embryonic structures, and the change in cell number in the CNS during development. We show that genome size is correlated with cell proliferation rate and with developmental rate at different stages of embryonic development, but that the correlation between genome size and cell size is only evident at later stages. We discuss the evolution of genome size in amphibians. Our discussion takes into account data that reportedly support two conflicting hypotheses: the “skeletal DNA” hypothesis, which claims a selective role for differences in genome size, and the “junk DNA” hypothesis, which claims that differences in genome size are a random result of the accumulation of noncoding DNA sequences. We show that these supposedly conflicting hypotheses can be integrated into a more complex and inclusive model for the evolution of genome size. J. Exp. Zool. (Mol. Dev. Evol.) 291:365–374, 2001. © 2001 Wiley‐Liss, Inc.
Presence of two neuropeptides in the fusiform ganglion and reproductive ducts of Octopus vulgaris: FMRFamide and gonadotropin‐releasing hormone (GnRH)
Authors: Di Cristo Carlo , Paolucci Marina , Iglesias Josè , Sanchez Javier , Di Cosmo Anna 
Published: August 2002

AbstractWe have found evidence of FMRFamide‐like and cGnRH‐I‐like immunoreactivity in the central nervous system (CNS) and in the reproductive ducts of both female and male cephalopod Octopus vulgaris. Cell bodies and fibers were immunolocalized in the fusiform ganglion from which the nerves that reach the female and male reproductive ducts arise. FMRFamide‐like and cGnRH‐I‐like immunoreactive nerve endings were present in the oviduct, and in the oviducal gland of the female and in the seminal vesicle of the male. The GnRH‐like peptide from the reproductive ducts has been partially characterized by HPLC. The retention time of the Octopus vulgaris GnRH‐like peptide was similar to the retention time of cGnRH‐I. Based on these observations we suggest that FMRFamide‐like and a novel GnRH‐like peptide are involved in the control of reproductive ducts of Octopus vulgaris. One possibility is that the peptides affect gamete transport. Another possibility is that they regulate secretory products such as mucus and mucilaginous substances from the oviducal gland and the seminal vesicle. Our data provide further evidence to support the hypothesis of the existence of a central and peripheral peptidergic control of reproduction of Octopus vulgaris. J. Exp. Zool. 292:267–276, 2002. © 2002 Wiley‐Liss, Inc.
Synthesis of N‐(2‐chloro‐3,4‐dimethoxybenzylideneamino)guanidinium acetate [α‐14C]
Authors: Almeida Maria , Boman Arne , Lundstedt Torbjörn 
Published: August 2002

Abstract14C‐Labelled N‐(2‐chloro‐3,4‐dimethoxybenzylideneamino)guanidinium acetate has been synthesized as a part of a four‐step procedure which involved decarboxylation of 2‐chloro‐3,4‐dimethoxybenzoic acid by Pb(OAc)4 to give 2‐chloro‐3,4‐dimethoxy‐1‐iodobenzene, followed by a selective lithiation at the iodine position and electrophilic substitution with N,N‐dimethylformamide [α‐14C] and final reaction with aminoguanidine bicarbonate. The specific activity was 59 mCi/mmol and the overall yield 49%. Copyright © 2002 John Wiley & Sons, Ltd.
Ultrastructure of the hindgut of Drosophila larvae, with special reference to the domains identified by specific gene expression patterns
Authors: Murakami Ryutaro , Shiotsuki Yumi 
Published: August 2002

AbstractThe hindgut of Drosophila larvae consists of nine domains that have been distinguished by specific gene expression patterns. In the present study, we examined the ultrastructure of the hindgut of Drosophila larvae, with special reference to the domains, in order to determine whether or not the domains are morphologically distinct functional units. Each domain showed specific ultrastructural features that suggested specific corresponding functions. According to the morphological features, terms are proposed for each domain: the imaginal ring; the “pylorus,” which has a thick cuticular layer and well‐developed sphincter muscles; the “large intestine,” which occupies a major middle portion of the hindgut and has a unique dorsal and ventral subdivision; “border cells,” which delineate the anterior and posterior borders of the large intestine and the border between the dorsal and ventral domains of the large intestine; and the “rectum,” which is situated at the posterior end of the hindgut and has a thick cuticular layer and sphincter muscles. The morphological features indicate that the large intestine has active absorptive activities. The domains, which have been distinguished by gene expressions, were demonstrated to be functional tissue units of the gut. J. Morphol. 248:144–150, 2001. © 2001 Wiley‐Liss, Inc.
Measurement of left ventricular dimensions and function in patients with dilated cardiomyopathy
Authors: Strohm Oliver , Schulz‐Menger Jeanette , Pilz Bernhard , Osterziel Karl‐Josef , Dietz Rainer , Friedrich Matthias G. 
Published: August 2002

AbstractStudies on medical therapy in heart failure are focused on changes of left ventricular (LV) dimensions and function. These changes may be small, requiring a large study group. We measured LV parameters (LV volumes, LV ejection fraction (LV‐EF), and left ventricular mass (LVM)) with two‐dimensional echocardiography (2D‐echo) and magnetic resonance imaging (MRI) in 50 patients. Based on the difference between the measurements, we determined the variance of the results and calculated the sample sizes needed to detect changes of baseline values. For the calculated and measured parameters we found significant differences between the two techniques: LV‐EF and LVM were higher in 2D‐echo, and LV dimensions were comparable. The sample size to detect relevant changes from baseline with MRI was significantly (P < 0.01) smaller than in 2D‐echo. We conclude that MRI is superior in clinical studies on left ventricular dimensional and functional changes, since measurements are more reproducible and the required sample size is substantially smaller, thereby reducing costs. J. Magn. Reson. Imaging 2001;13:367–371. © 2001 Wiley‐Liss, Inc.
Investigation of the factors responsible for burns during MRI
Authors: Dempsey Mary F. , Condon Barrie , Hadley Donald M. 
Published: August 2002

AbstractNumerous reported burn injuries have been sustained during clinical MRI procedures. The aim of this study was to investigate the possible factors that may be responsible for such burns. Experiments were performed to investigate three possible mechanisms for causing heating in copper wire during MRI: direct electromagnetic induction in a conductive loop, induction in a resonant conducting loop, and electric field resonant coupling with a wire (the antenna effect). Maximum recorded temperature rises were 0.6°C for the loop, 61.1°C for the resonant loop, and 63.5°C for the resonant antenna. These experimental findings suggest that, contrary to common belief, it is unlikely that direct induction in a conductive loop will result in thermal injury. Burn incidents are more likely to occur due to the formation of resonant conducting loops and from extended wires forming resonant antenna. The characteristics of resonance should be considered when formulating safety guidelines. J. Magn. Reson. Imaging 2001;13:627–631. © 2001 Wiley‐Liss, Inc.
Rapid screening and identification of cytochalasins by electrospray tandem mass spectrometry
Authors: Prasain Jeevan Kumar , Ueki Masashi , Stefanowicz Piotr , Osada Hiroyuki 
Published: August 2002

AbstractThe cytochalasin class of fungal metabolites was analyzed by electrospray ionization tandem mass spectrometry (ESI‐MS/MS) with the aim of developing a methodology for their rapid identification in microbial extracts. ESI‐MS analyses of reference cytochalasins were performed and several product ions were produced in MS/MS experiments on parent ions that are structurally characteristic. A precursor ion search was performed to detect cytochalasins in an ethyl acetate extract of fungal strain RK97‐F21. Three cytochalasins were detected and one of the components was identified as epoxycytochalasin H by comparing the tandem mass spectra of the product ions with those of reference compounds. This finding was further validated by LC/MS and LC/MS/MS experiments. Copyright © 2002 John Wiley & Sons, Ltd.
Electrospray ionization mass spectrometry of ginsenosides
Authors: Miao Xiu‐Sheng , Metcalfe Chris D. , Hao Chunyan , March Raymond E. 
Published: August 2002

AbstractGinsenosides Rb1, Rb2, Rc, Rd, Re, Rf, Rg1, Rg2 and F11 were studied systematically by electrospray ionization mass spectrometry in positive‐ and negative‐ion modes with a mobile‐phase additive, ammonium acetate. In general, ion sensitivities for the ginsenosides were greater in the negative‐ion mode, but more structural information on the ginsenosides was obtained in the positive‐ion mode. [M + H]+, [M + NH4]+, [M + Na]+ and [M + K]+ ions were observed for all of the ginsenosides studied, with the exception of Rf and F11, for which [M + NH4]+ ions were not observed. The signal intensities of [M + H]+, [M + NH4]+, [M + Na]+ and [M + K]+ ions varied with the cone voltage. The highest signal intensities for [M + H]+ and [M + NH4]+ ions were obtained at low cone voltage (15–30 V), whereas those for [M + Na]+ and [M + K]+ ions were obtained at relatively high cone voltage (70–90 V). Collision‐induced dissociation yielded characteristic positively charged fragment ions at m/z 407, 425 and 443 for (20S)‐protopanaxadiol, m/z 405, 423 and 441 for (20S)‐protopanaxatriol and m/z 421, 439, 457 and 475 for (24R)‐pseudoginsenoside F11. Ginsenoside types were identified by these characteristic ions and the charged saccharide groups. Glycosidic bond cleavage and elimination of H2O were the two major fragmentation pathways observed in the product ion mass spectra of [M + H]+ and [M + NH4]+. In the product ion mass spectra of [M − H]−, the major fragmentation route observed was glycosidic bond cleavage. Adduct ions [M + 2AcO + Na]−, [M + AcO]−, [M − CH2O + AcO]−, [M + 2AcO]2−, [M − H + AcO]2− and [M − 2H]2− were observed at low cone voltage (15–30 V) only. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization of tick‐borne encephalitis virus from latvia: Evidence for co‐circulation of three distinct subtypes
Authors: Lundkvist Åke , Vene Sirkka , Golovljova Irina , Mavtchoutko Violeta , Forsgren Marianne , Kalnina Vaira , Plyusnin Alexander 
Published: August 2002

AbstractViruses of the tick‐borne encephalitis (TBE) antigenic complex within the family Flaviviridae cause a variety of diseases, including uncomplicated febrile illness, meningoencephalitis, and hemorrhagic fever. Different domesticated animals or wildlife species often act as reservoir hosts and ixodid ticks serve as vectors. Although TBE is a serious problem in Latvia, the knowledge concerning TBE virus (TBEV) strains circulating in the country is most limited. Only two strains (Latvia‐1‐96 isolated from a TBE patient, and RK1424 originating from an Ixodes persulcatus tick), which belonged to the Siberian and the Far Eastern subtypes of TBEV, respectively, have previously been characterized. In the present study, we concentrated on the western and central regions of Latvia, with predominantly Ixodes ricinus ticks. Five virus strains were isolated from serum samples of patients with clinical symptoms of an acute TBE infection. Nucleotide sequences encoding the envelope (E) protein of TBEV, which were recovered from the five TBEV isolates, showed the highest level of identity to the corresponding sequences of the prototype strain Neudoerfl and other European strains of the Western TBEV subtype characterized previously. Accordingly, phylogenetic analysis placed the new Latvian isolates within the Western genetic lineage of TBEV. Taken together with earlier observations, the results proved that all three TBEV subtypes are co‐circulating in Latvia and indicated that the genetic diversity of TBEV within certain geographical areas is much more complex than previously believed. J. Med. Virol. 65:730–735, 2001. © 2001 Wiley‐Liss, Inc.
Herpes simplex virus isolates with reduced adefovir susceptibility selected in vivo by foscarnet therapy
Authors: Bestman‐Smith Julie , Boivin Guy 
Published: August 2002

AbstractSequential herpes simplex virus (HSV) isolates from AIDS patients receiving foscarnet therapy were evaluated for susceptibility to adefovir. Foscarnet‐resistant isolates with DNA polymerase mutations in regions II, VI, and between I and VII were also associated with an important decrease in susceptibility to adefovir (mean IC50 increase: 4.6‐fold compared to pre‐foscarnet or wild‐type isolates) suggesting that adefovir‐resistant HSV could be selected in vivo by foscarnet therapy. J. Med. Virol. 67:88–91, 2002. © 2002 Wiley‐Liss, Inc.
Immunisation of Balb/c mice with severely attenuated murine cytomegalovirus mutants induces protective cellular and humoral immunity
Authors: Morley Peter J. , Ertl Peter , Sweet Clive 
Published: August 2002

AbstractPreviously, we showed that two temperature‐sensitive mutants of murine cytomegalovirus (tsm5 and tsm30) expressed immediate‐early (IE‐1), early (E‐1), and late (gB) phase genes in the tissues of immunocompetent Balb/c mice, yet failed to produce infectious progeny virus in any tissue at any time at 1–21 days post‐infection. Mice inoculated intraperitoneally with tsm5 became latently infected, but this latent virus could not be reactivated as an infectious virus after immunosuppression, although all three transcripts were produced. Immunocompetent mice infected with tsm30 did not become latently infected. In the present study, immunodeficient SCID mice supported productive infection of both mutants, suggesting that low‐level viral replication does occur in immunocompetent mice, but that it is limited by the host immune response. This is supported by the observation that immunocompetent mice were protected against virulent K181 challenge even after immunisation with as few as 40 pfu of mutant virus, whereas UV‐inactivated mutant or K181 virus was not immunoprotective at doses of 40,000 pfu. Immunity induced by subcutaneous inoculation was also protective, whereas that induced by intragastric immunisation was not. Protection was lifelong (18 months). Although tsm5 induced high antibody titres, there was little evidence of an antibody response to tsm30. In contrast, a significant CD8+ CTL response to the Balb/c immunodominant IE‐1 nonapeptide (YPHFMPTNL) was elicited by both mutants, as determined by an interferon‐γ ELISPOT assay, although this response was lower than that induced by K181 infection. In addition, CTLs specific for m04 (YGPSLYRRF) and M84 (AYAGLFTPL) peptides could be detected at low frequency after K181, tsm5, and tsm30 immunisation. Such protective immunity did not prevent the challenge K181 virus from entering the latent state, but it appeared to reduce the frequency of reactivation. J. Med. Virol. 67:187–199, 2002. © 2002 Wiley‐Liss, Inc.