bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fetal atrioventricular valve junction in normal fetuses and in fetuses with complete atrioventricular septal defect assessed by 4D volume rendering
Authors: Viñals F. , Pacheco V. , Giuliano A. 
Published: May 2006

AbstractObjectivesTo assess the feasibility and clinical potential of 4D volume rendering of the atrioventricular (AV) valve junction, to standardize the acquisition method, and to display the AV valve junction morphology in normal fetuses and in those with a complete atrioventricular septal defect (AVSD).MethodsWe performed sonography in 40 normal fetuses and 10 fetuses with complete AVSD, and volume datasets were acquired from apical and lateral four‐chamber views. The render box was placed systematically. First, it included the AV valves, with the reference dot at the level of the crux of the heart. Then, it included the papillary muscles, with the reference dot in the interventricular septum at the level of the distal opening of the tricuspid valve leaflet.ResultsVolume acquisition and rendering were technically possible in all cases. Volume rendering of the left ventricle showed the position of the anterolateral and posteromedial papillary muscles in 36/40 normal fetuses (90%). At the level of the right ventricle, the septal, anterior and posterior papillary muscles were visualized in 33/40 normal fetuses (82%). In cases of complete AVSD, the AV valve has five leaflets, with anterosuperior and posteroinferior bridging leaflets straddling the septa. The morphology of the anterosuperior bridging leaflets and the abnormal position of the papillary muscles could be displayed in all cases.ConclusionsOur study suggests that some of the components of the AV junction can be reconstructed easily from sonographic volumes acquired from an apical or lateral four‐chamber view. This new technique may have a role in obtaining views that are not easily accessible by standard sonography, enabling a rapid complementary assessment of normal and abnormal intracardiac anatomy. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Evaluating the consequences of habitat fragmentation: a case study in the common forest herb Trillium camschatcense
Authors: Tomimatsu Hiroshi , Ohara Masashi 
Published: May 2006

AbstractThe effects of habitat fragmentation on remnant plant populations have rarely been studied extensively using a single species. We have attempted to quantify the effects of forest fragmentation (primarily that of population size) on populations of Trillium camschatcense, a representative spring herb in the Tokachi plain of Hokkaido, Japan. In this region, intensive agricultural development over the past 100 years has divided once‐large, continuous populations of this species into small, isolated fragments. Small populations generally produced fewer seeds than large populations, although this result differed between years. The level of seed production is unlikely to explain demographic structures based on life‐history stages. Instead, the stage structure was better explained by population size, seedling recruitment being limited in smaller populations. This could be associated with edge effects because the stage structure in small populations corresponded well to that observed in forest edges, where altered microclimatic conditions strongly limit seedling recruitment. Small populations also experienced stochastic loss of rare alleles at allozyme loci as well as biparental inbreeding. Although one consequence of these changes is reduced fertility, the long‐term effects on population growth can be controversial in long‐lived forest herbs, since the negative effect on fertility may vary across years, and population growth rate may not be sensitive to changes in fertility. Further studies of long‐term demography will reveal whether and how habitat fragmentation could limit population growth of remnant populations more than a century after fragmentation.
Soil nutrient status after bamboo flowering and death in a seasonal tropical forest in western Thailand
Authors: Takahashi Masamichi , Furusawa Hitomi , Limtong Pitayakon , Sunanthapongsuk Vanlada , Marod Dokrak , Panuthai Samruan 
Published: May 2006

AbstractWe have examined the surface (0–10 cm) soil characteristics of sites after bamboo (Cephalostachyum pergracile) mass flowering and death (DB sites) in comparison with sites with living bamboo (Bambusa tulda) (LB sites) in a seasonal tropical forest in Thailand. One year after bamboo flowering the DB sites were acidic with lower concentrations of exchangeable Ca and Mg and soil nitrogen than the LB sites. Therefore, although leaf and root litter of the dead bamboo was deposited in the DB sites after bamboo flowering, soil nutrient status decreased.
Involvement of muscarinic acetylcholine receptors in chloride secretion by cultured rat epididymal epithelium
Authors: Du Jian‐Yang , Zuo Wu‐Lin , Chen Min‐Hui , Xiang Hui , Zhou Wen‐Liang 
Published: May 2006

AbstractThe aim of our present study was to investigate the short‐circuit current response to carbachol in cultured rat cauda epididymal epithelia and the signal transduction mechanisms involved. Carbachol added basolaterally induced a concentration‐dependent increase in short‐circuit current (Isc) across the epididymal epithelium consisting of a rapidly rising phase and a long term sustained response. The response was almost abolished by removing Cl− from the extracellular medium and blockable by pretreating the tissues with DPC, indicating a substantial contribution of Cl− secretion to the carbachol‐induced response. The muscarinic acetylcholine receptor antagonist atropine inhibited the response, but the nicotinic acetylcholine receptors antagonist curarine had no effect, suggesting that only the muscarinic acetylcholine receptors mediated the secretory response of the basolateral side of rat cauda epididymal epithelium to carbachol. Addition of carbachol to the apical side of the tissue was found not to elicit an Isc response. These results suggested that muscarinic receptors are present in the basolateral side of rat cauda epididymal epithelium. Activation of these receptors by acetylcholine released from the nerve endings regulates epididymal transepithelial Cl− secretion. Cholinergic stimulation therefore contributes to the formation of luminal fluid microenvironment.
Electrosurgical endoscopic cordectomy with microdissection electrodes: a comparative study with CO2 laser
Authors: Basterra J , Zapater E , Moreno R , Hernández R 
Published: May 2006

Microdissection electrodes (MEs) have previously been used to perform endoscopic cordectomies.We designed a prospective study in order to compare the ME with the CO2 laser technique. Over two years, 20 patients with T1 glottic carcinoma were operated on with CO2 laser and 20 with MEs. The device was chosen alternatively for each new patient. Two patients in both treatment groups had slight glottic incompetence. Three patients in each group showed web formation. The only granuloma was observed in a CO2 laser patient. Seven of the ME patients developed slight dysphonia, 10 developed medium grade dysphonia and three developed severe dysphonia. Seven of the CO2 laser patients developed slight dysphonia, seven developed medium grade dysphonia and six developed severe dysphonia. No statistically significant differences were observed on comparing the grade of dysphonia with patient age, T stage, type of cordectomy or surgical device.We consider the ME to be a useful and inexpensive alternative to CO2 laser.
Auditory neuropathy in a patient with mitochondrial myopathy and multiple mtDNA deletions
Authors: Forli F , Mancuso M , Santoro A , Dotti M T , Siciliano G , Berrettini S 
Published: May 2006

Auditory neuropathy (AN) is a hearing disorder characterized by the absence or severe distortion of the auditory brainstem responses, in the presence of preserved otoacoustic emissions. This peculiar combination suggests the presence of a defect impinging upon the functional complex formed by inner hair cells, the primary afferents (spiral ganglion neurones) and the first order synapses between hair cells and the cochlear nerve. Typically, AN patients show a severe speech perception impairment, which appears reduced out of proportion to pure tone threshold, but the clinical presentation of AN is quite complex.Hearing loss is a common symptom associated with mitochondrial diseases; however, AN has only rarely been reported in these disorders.Here we report a rare association, the first case observed in Italy, in a patient with autosomal recessive mitochondrial myopathy and mitochondrial DNA multiple deletions, and a hearing deficit with the audiological and electrophysiological features of AN.
Reinke's oedema, hormones and hormone replacement therapy
Authors: Tsikoudas A , Kochillas X , Vernham G 
Published: May 2006

Objective: To study the implications of hormone replacement therapy (HRT) treatment in the pathogenesis of Reinke's oedema (via a possible pseudo-hypothyroidism effect), and also to study why the disease affects a predominantly post-menopausal female population.Design: Prospective case series study.Setting: Two teaching hospitals and two district general hospitals in Scotland, UK.Subjects: Thirty-three patients diagnosed with Reinke's oedema who presented in the out-patient department before or after treatment.Results: Thyroid function tests were normal in all but two cases. Only three patients were receiving HRT treatment.Conclusions: The study produced no evidence to support a relationship between HRT treatment and the pathogenesis of Reinke's oedema; this supports previous studies which concluded that thyroid function was not related to the development of Reinke's oedema. Some new ideas regarding hormonal factors in Reinke's oedema are discussed.
Loss-cone index in distribution function in a hot magnetized plasma
Authors: SINGHAL R. P. , TRIPATHI A. K. 
Published: May 2006

Abstract.The components of the dielectric tensor for the distribution function given by Leubner and Schupfer have been obtained. The effect of the loss-cone index appearing in the particle distribution function in a hot magnetized plasma has been studied. A case study has been performed to calculate temporal growth rates of Bernstein waves using the distribution function given by Summers and Thorne and Leubner and Schupfer. The effect of the loss-cone index on growth rates is found to be quite different for the two distribution functions.
Weakly nonlinear waves in magnetized plasma with a slightly non-Maxwellian electron distribution. Part 1. Stability of solitary waves
Authors: ALLEN M.A. , PHIBANCHON S. , ROWLANDS G. 
Published: May 2006

Abstract.Weakly nonlinear waves in strongly magnetized plasma with slightly non-isothermal electrons are governed by a modified Zakharov–Kuznetsov (ZK) equation, containing both quadratic and half-order nonlinear terms, which we refer to as the Schamel–Korteweg–de Vries–Zakharov–Kuznetsov (SKdVZK) equation. We present a method to obtain an approximation for the growth rate, γ, of sinusoidal perpendicular perturbations of wavenumber, k, to SKdVZK solitary waves over the entire range of instability. Unlike for (modified) ZK equations with one nonlinear term, in this method there is no analytical expression for kc, the cut-off wavenumber (at which the growth rate is zero) or its corresponding eigenfunction. We therefore obtain approximate expressions for these using an expansion parameter, a, related to the ratio of the nonlinear terms. The expressions are then used to find γ for k near kc as a function of a. The approximant derived from combining these analytical results with the ones for small k agrees very well with the values of γ obtained numerically. It is found that both kc and the maximum growth rate decrease as the electron distribution becomes progressively less peaked than the Maxwellian. We also present new algebraic and rarefactive solitary wave solutions to the equation.
CD9 protein appears on growing mouse oocytes at the time when they develop the ability to fuse with spermatozoa
Authors: Komorowski Sebastian , Baranowska Barbara , Maleszewski Marek 
Published: May 2006

SummaryCD9 is a member of the tetraspanin superfamily proteins and is the only protein on the mouse oocyte which is known to be indispensable in sperm–egg fusion. Here, using indirect immunofluorescence we show that CD9 appears on the oolemma during the early stages of the growth of the oocyte, when it measures 13–22 μm in diameter. When the oocyte reaches a diameter of 17–22 μm, the density of CD9 in its oolemma is similar to the density of this protein in the cell membrane of the fully grown secondary oocyte. The appearance of CD9 in growing oocytes correlates with the previously reported time of the acquisition of fusibility between the spermatozoon and the egg. Accordingly we propose that during oogenesis the development of the ability of the oolemma to fuse with sperm may be regulated by synthesis of CD9 by the oocyte.
Developmental capacity of Antarctic minke whale (Balaenoptera bonaerensis) vitrified oocytes following in vitro maturation, and parthenogenetic activation or intracytoplasmic sperm injection
Authors: Fujihira Takuma , Kobayashi Mariko , Hochi Shinichi , Hirabayashi Masumi , Ishikawa Hajime , Ohsumi Seiji , Fukui Yutaka 
Published: May 2006

SummaryThe present study investigated the effects of the sexual maturity of oocyte donors on in vitro maturation (IVM) and the parthenogenetic developmental capacity of fresh minke whale oocytes. The effects of cytochalasin B (CB) pretreatment and two types of cryoprotectant solutions (ethylene glycol (EG) or ethylene glycol and dimethylsulfoxide (EG + DMSO)) on the in vitro maturation of vitrified immature whale oocytes were compared, and the developmental capacity of vitrified immature whale oocytes following IVM and intracytoplasmic sperm injection examined (ICSI). The maturation rate did not differ significantly with sexual maturity (adult, 60.9%; prepubertal, 53.1%), but the parthenogenetic activation rate of oocytes from adult donors (76.7%) was significantly higher (p < 0.05) than that of oocytes from prepubertal donors (46.4%). The maturation rates after vitrification and warming were not significantly different between the EG (22.2%) and EG + DMSO groups (30.2%), or between the CB-treated (30.4%) and non-CB-treated groups (27.3%). These results indicate that parthenogenetic activation of in vitro matured oocytes from adult minke whales was superior to that from prepubertal whales, but that the developmental capacity of the whale oocytes after parthenogenetic activation or ICSI was still low. The present study also showed that CB treatment before vitrification and two kinds of cryoprotectants did not improve the IVM rate following the vitrification of immature whale oocytes.
The localization of LAP2β during pronuclear formation in bovine oocytes after fertilization or activation
Authors: Isaji Mamiko , Iwata Hisataka , Harayama Hiroshi , Miyake Masashi 
Published: May 2006

SummaryWe have shown that the assembly of lamin-associated polypeptide (LAP) 2β was detected surrounding the chromatin mass around the time of extrusion of the second polar body (PB) in some fertilized oocytes, but not in most activated oocytes, by using A23187 and cycloheximide (CaA + CH). Here, we immunohistologically analysed the correlation between LAP2β assembly and chromatin condensation in fertilized and activated oocytes during the second meiosis. In bovine cumulus cells, the onset of LAP2β assembly was observed around anaphase chromosomes with strongly phosphorylated histone H3. No LAP2β assembled around the chromosomes in the first and second polar bodies and the alternative oocyte chromatin (oCh) if histone H3 was phosphorylated. Only histone H3 of oCh was completely dephosphorylated during the telophase II/G1 transition (Tel II/G1), and then LAP2β assembled around only the oCh without phosphorylated histone H3. In the oocytes activated by CaA + CH, LAP2β did not assemble around the condensed oCh during the Tel II/G1 transition, although their histone H3 dephosphorylation occurred rather rapidly compared with that of the fertilized oocytes. The patterns of histone H3 dephosphorylation and LAP2β assembly in oocytes activated by CaA alone showed greater similarity to those in fertilized oocytes than to those in oocytes activated by CaA + CH. These results show that LAP2β assembles around only oCh after complete dephosphorylation of histone H3 after fertilization and activation using CaA alone, and that the timing of histone H3 dephosphorylation and LAP2β assembly in these oocytes is different from that of somatic cells. The results also indicate that CH treatment inhibits LAP2β assembly around oCh but not histone H3 dephosphorylation.
Requirement for a localized, IP3R-generated Ca2+transient during the furrow positioning process in zebrafish zygotes
Authors: Lee Karen W. , Webb Sarah E. , Miller Andrew L. 
Published: May 2006

SummaryWe report that the first localized Ca2+transient visualized in the blastodisc cortex of post-mitotic zebrafish zygotes has unique features. We confirm that this initial ‘furrow positioning’ Ca2+transient precedes the physical appearance of the first cleavage furrow at the blastodisc surface and that it has unique dynamics, which distinguish it from the subsequent furrow propagation transients that develop from it. This initial transient displays a distinct rising phase that peaks prior to the initiation of the two linear, subsurface, self-propagating Ca2+waves that constitute the subsequent furrow propagation transient. Through the carefully timed introduction of the Ca2+buffer, dibromo-BAPTA, we also demonstrate the absolute requirement of this initial rising phase Ca2+transient in positioning the furrow at the blastodisc surface: no rising phase transient, no cleavage furrow. Likewise, the introduction of the inositol 1,4,5-trisphosphate receptor (IP3R) antagonist, 2-aminoethoxydiphenyl borate, eliminates both the rising phase transient and the appearance of the furrow at the cell surface. On the other hand, antagonists of the ryanodine receptor and NAADP-sensitive channels, or simply bathing the zygote in Ca2+-free medium, have no effect on the generation of the rising phase positioning transient or the appearance of the furrow at the surface. This suggests that like the subsequent propagation and deepening/zipping Ca2+transients, the rising phase furrow positioning transient is also generated specifically by Ca2+released via IP3Rs. We propose, however, that despite being generated by a similar Ca2+release mechanism, the unique features of this initial transient suggest that it might be a distinct signal with a specific function associated with positioning the cleavage furrow at the blastodisc surface.
Expression of mRNA and protein localization of epidermal growth factor and its receptor in goat ovaries
Authors: Silva José R.V. , van den Hurk Robert , Figueiredo José R. 
Published: May 2006

SummaryTo examine the possibility that epidermal growth factor (EGF) and its receptor (EGF-R) are expressed throughout folliculogenesis, we studied the presence and distribution of EGF and EGF-R in goat ovaries. Ovaries of goats were collected and either fixed in paraformaldehyde for immunohistochemical localization of proteins, or used for the isolation of follicles, luteal cells and ovarian surface epithelium to study mRNA expression for EGF and EGF-R, using the reverse transcriptase polymerase chain reaction. EGF protein and mRNA were found in primordial, primary and secondary follicles as well as in small and large antral follicles and in surface epithelium, but in corpora lutea only the protein could be detected. Antral follicles expressed EGF mRNA in oocyte, cumulus, mural granulosa and theca cells. For EGF-R, both protein and mRNA were present at all stages of follicular development and in all antral follicular compartments. EGF-R protein and mRNA were also found in corpora lutea and surface epithelium. It is concluded that EGF and its receptor are expressed in goat ovarian follicles at all stages of follicle development, in corpora lutea, and in ovarian surface epithelium.
Behaviour of the vitelline envelope inBufo arenarumoocytes maturedin vitroin blockade to polyspermy
Authors: Oterino J. , Sánchez Toranzo G. , Zelarayán L. , Ajmat M.T. , Bonilla F. , Bühler M.I. 
Published: May 2006

SummaryDuring activation of amphibian eggs, cortical granule exocytosis causes elaborate ultrastructural changes in the vitelline envelope. These changes involve modifications in the structure of the vitelline envelope and formation of a fertilization envelope (FE) that can no longer be penetrated by sperm. InBufo arenarum, as the egg traverses the oviduct, the vitelline envelope is altered by a trypsin-like protease secreted by the oviduct, which induces an increased susceptibility of the vitelline envelope to sperm lysins. Full-grown oocytes ofB. arenarum, maturedin vitroby progesterone, are polyspermic, although cortical granule exocytosis seems to occur within a normal chronological sequence. These oocytes can be fertilized with or without trypsin treatment, suggesting that the vitelline envelope is totally sperm-permeable. Vitelline envelopes without trypsin treatment cannot retain either gp90 or gp96. This suggests that these glycoproteins are involved in the block to polyspermy and that trypsin treatment of maturedin vitrooocytes before insemination is necessary to enable vitelline envelopes to block polyspermy. The loss of the binding capacity in vitelline envelopes isolated fromB. arenarumoocytes maturedin vitrowith trypsin treatment and activated by electric shock suggests that previous trypsin treatment is a necessary step for sperm block to occur. Whenin vitromatured oocytes were incubated with the product of cortical granules obtained fromin vitromatured oocytes (vCGP), vitelline envelopes with trypsin treatment were able to block sperm entry. These oocytes exhibited the characteristic signs of activation. These results support the idea thatB. arenarumoocytes can be activated by external stimuli and suggest the presence of unknown oocyte surface receptors linked to the activation machinery in response to fertilization. Electrophoretic profiles obtained by SDS-PAGE of solubilized vitelline envelopes from oocytes maturedin vitrorevealed the conversion of gp40 (in vitromatured oocytes, without trypsin treatment) to gp38 (ascribable to trypsin activity or cortical granule product activity, CGP) and the conversion of gp70 to gp68 (ascribable to trypsin activity plus CGP activity). Taking into account that only the vitelline envelopes of in vitromatured oocytes with trypsin treatment and activated can block sperm entry, we may suggest that the conversion of gp70 to gp68 is related to the changes associated with sperm binding.