bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genomic in situ hybridization analysis of Brassica napus × Orychophragmus violaceus hybrids and production of B. napus aneuploids
Authors: Hua Y. W. , Li Z. Y. 
Published: March 2006

AbstractTo further utilize the valuable germplasm Orychophragmus violaceus for Brassica genetics and breeding, a B. napus × O. violaceus cross was repeated with embryo rescue. All F1 plants except one B. napus haploid were mixoploids (2n = 17–39 in ovaries) with 2n = 31, 37, 38 and 39 as the maximal chromosome numbers in individuals, but the higher numbers mostly appeared in pollen mother cells (PMCs) with a preponderance of 2n = 30, 37 and 38. Only one chromosome and one chromosome segment of O. violaceus were detected at a low frequency in some ovary cells and PMCs with 2n = 37, 38 and 39 as determined by genomic in situ hybridization analysis. The fatty acid profiles of seeds from the majority of the F1 and F2 plants were similar to those of female B. napus cv. ‘Oro’, but some were obviously different in the percentages of oleic, linoleic and erucic acids, and some F2 plants (2n = 38) with good seed set had high percentages of oleic (>70.0%) or linoleic (to 38.3%) acids and low erucic acid (<1%). Subsequently, many kinds of B. napus aneuploids (2n = 28, 30, 34, 36, 37, 39 and 42), without O. violaceus chromosomes, were derived from F2 progeny and microspores of partial F1 plants. Finally, the cytological mechanisms behind the variations in chromosome numbers were discussed together with the implications of these aneuploids for Brassica genome research and of the plants with altered fatty acid profiles for improving the oil quality of B. napus.
Field analyses of horizontal gene flow among Vigna angularis complex plants
Authors: Yamamoto Y. , Sano C. M. , Tatsumi Y. , Sano H. 
Published: March 2006

AbstractRecent studies have indicated that spontaneous interspecies crossing commonly occurs among vascular plants, and therefore that horizontal gene flow from transgenic plants into wild relatives is unavoidable. Few surveys, however, have been conducted to determine an actual flow frequency for individual plant species. For the present estimation of gene flow among Vigna angularis complex (small red bean) plants, randomly amplified polymorphic DNA was analysed, the patterns of which differ between a cultivar, var. angularis and its wild counterpart, var. nipponensis. Cultivars and wild‐type plants were planted alternately and approximately 1% of the screened F1 beans of wild type were hybrid. These F1 hybrids were selected, allowed to self to produce F2 beans, and subsequent crossing between the F2 plants and wild type resulted in that 3.7% of the F3 generation possessed DNA fragments specific to the cultivar. These results indicate that gene flow actually occurs among V. angularis complex plants, and that transferred genes might be stably maintained by the offspring. The present observation cannot be directly applied to transgenic plants due to the lack of information as to whether or not artificially introduced genes behave as do native genes after horizontal movement. However, as gene flow is found to be inevitable in this species, specific assessment of whether or not the gene to be introduced confers a significant selective advantage to the host is critical for utilization of genetically modified plants in future.
Indirect activation of neuronal noncapacitative Ca2+ entry is the final step involved in the neurotoxic effect of Tityus serrulatus scorpion β‐toxin
Authors: Grolleau Françoise , Stankiewicz Maria , Kielbasiewicz Ewa , Martin‐Eauclaire Marie‐France , Lavialle Céline , De Vente Jan , Lapied Bruno 
Published: March 2006

AbstractInterweaving strategies of electrophysiology, calcium imaging and immunocytochemistry bring new insights into the mode of action of the Brazilian scorpion Tityus serrulatusβ‐toxin VII. Pacemaker dorsal unpaired median neurons isolated from the cockroach central nervous system were used to study the effects of toxin VII. In current‐clamp, 50 nm toxin VII produced a membrane depolarization and reduced spiking. At 200 nm, depolarization associated with multiphasic effects was seen. After artificial hyperpolarization, plateau potentials on which spontaneous electrical activity appeared were observed. In voltage clamp, toxin VII induced a negative shift of the voltage dependence of sodium current activation without significant effect on steady‐state inactivation. In addition, toxin VII produced a permanent TTX‐sensitive holding inward current, indicating that background sodium channels were targeted by β‐toxin. Cell‐attached patch recordings indicated that these channels were switched from unclustered single openings to current fluctuating between distinct subconductance levels exhibiting increased open probability and open‐time distribution. Toxin VII also produced a TTX‐sensitive [Ca2+]i rise. Immunostaining with Cav2.2(α1b) antibodies and calcium imaging data obtained with ω‐CgTx GVIA indicated that N‐type high‐voltage‐activated calcium channels initiated calcium influx and were an essential intermediate in the pathway linking toxin VII‐modified sodium channels to the activation of an additional route for calcium entry. By using inhibitors of (i) noncapacitative calcium entry (inhibitor LOE‐908), (ii) NO‐sensitive guanylyl cyclase (ODQ) and (iii) phosphodiesterase 2 (EHNA), together with cGMP antibodies, we demonstrated that noncapacitative calcium entry was the final step in a complex combination of events that was initiated by toxin VII‐alteration of sodium channels and then involved successive activation of other membrane ion channels.
S1P inhibits gap junctions in astrocytes: involvement of Giand Rho GTPase/ROCK
Authors: Rouach Nathalie , Pébay Alice , Même William , Cordier Jocelyne , Ezan Pascal , Etienne Eric , Giaume Christian , Tencé Martine 
Published: March 2006

AbstractSphingosine‐1‐phosphate (S1P) is a potent and pleiotropic bioactive lysophospholipid mostly released by activated platelets that acts on its target cells through its own G protein‐coupled receptors. We have previously reported that mouse striatal astrocytes expressed mRNAs for S1P1and S1P3receptors and proliferate in response to S1P. Here, we investigated the effect of S1P on gap junctions. We show that a short‐term exposure of astrocytes to S1P causes a robust inhibition of gap junctional communication, as demonstrated by dye coupling experiments and double voltage‐clamp recordings of junctional currents. The inhibitory effect of S1P on dye coupling involves the activation of both Giand Rho GTPases. Rho‐associated kinase (ROCK) also plays a critical role. The capacity of S1P to activate a Rho/ROCK axis in astrocytes is demonstrated by the typical remodeling of actin cytoskeleton. Connexin43, the protein forming gap junction channels, is a target of the Gi‐ and Rho/ROCK‐mediated signaling cascades. Indeed, as shown by Western blots and confocal immunofluorescence, its nonphosphorylated form increases following S1P treatment and this change does not occur when both cascades are disrupted. This novel effect of S1P may have an important physiopathological significance when considering the proposed roles for astrocyte gap junctions on neuronal survival.
In vivo optical recordings of synaptic transmission and intracellular Ca2+ and Cl– in the superior colliculus of fetal rats
Authors: Sakata Yoshiyuki , Fujioka Takashi , Endoh Hisashi , Nakamura Shoji 
Published: March 2006

AbstractAlthough the N‐methyl‐d‐aspartate (NMDA) receptor is known to play a crucial role in activity‐dependent remodeling of synaptic connections in the fetal superior colliculus (SC), its contribution to the electrical activity of fetal SC neurons has not been determined. Furthermore, whether γ‐aminobutyric acid (GABA)‐mediated inhibition occurs either as early as prenatal periods or only after eye opening has been controversial. We therefore performed optical recordings using voltage‐, Ca2+‐ and Cl–‐sensitive fluorescent dyes to analyse synaptic transmission and changes in intracellular Ca2+ and Cl– in the SC of fetal rats that were still connected with the dams by the umbilical cord. Excitatory and inhibitory responses were evoked by focal SC stimulation. The excitatory synaptic responses are composed of early and late components. The early component was mediated by both non‐NMDA and NMDA receptors, whereas the late component occurred mainly via NMDA receptors. Train pulse stimulation at higher currents was required for induction of the inhibition, which was antagonized by bicuculline, and blocking of the GABA‐mediated inhibition by bicuculline uncovered masked excitatory synaptic responses. Focal SC stimulation induced increases in [Cl–]i and [Ca2+]i that were mediated by GABA‐A receptors and mainly by NMDA receptors, respectively. GABA antagonists augmented SC‐induced increases in [Ca2+]i. These results indicate that, in the fetal SC, excitatory and inhibitory synaptic transmissions occur before birth, that the NMDA receptor is a major contributor to excitatory synaptic transmission and increased [Ca2+]i, and that the GABA‐A receptor is already functioning to inhibit excitatory neurotransmission.
Selective impairment of GABAergic synaptic transmission in the flurothyl model of neonatal seizures
Authors: Isaeva Elena , Isaev Dmytro , Khazipov Rustem , Holmes Gregory L. 
Published: March 2006

AbstractNeonatal seizures can result in long‐term adverse consequences including alteration of seizure susceptibility and impairment in spatial memory. However, little is known about the effects of neonatal seizures on developmental changes occurring in synaptic transmission during the first postnatal weeks. The purpose of the present study was to examine the effect of neonatal seizures on several aspects of γ‐aminobutyric acid (GABA)ergic and glutamatergic synaptic transmission in the developing rat hippocampus. Flurothyl was used to induce multiple recurrent seizures in rat pups during the first postnatal days. Whole‐cell patch‐clamp recordings from the hippocampal CA3 pyramidal cell and extracellular recordings from the CA3 pyramidal cell layer were made in slice preparations. In rats that experienced neonatal seizures the amplitude of spontaneous inhibitory postsynaptic currents at P15–17 was decreased by 27% compared with controls, whereas neither frequency nor the kinetic properties were altered. Neonatal seizures did not affect the timing of the developmental switch in the GABAA signaling from excitatory to inhibitory. None of the studied parameters of glutamatergic postsynaptic currents was different between the flurothyl and control groups, including the amplitude and frequency of the spontaneous excitatory postsynaptic currents, the ratio of the amplitudes and frequencies of the α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) and N‐methyl‐d‐aspartate (NMDA)‐mediated spontaneous postsynaptic currents, and the kinetics of AMPA and NMDA mediated postsynaptic currents in the age groups P8–10 and P15–17. We suggest that the selective depression of the amplitude of GABAergic synaptic responses may contribute to the adverse neurological and behavioral consequences that occur following neonatal seizures.
What drives elevational patterns of diversity? A test of geometric constraints, climate and species pool effects for pteridophytes on an elevational gradient in Costa Rica
Authors: Kluge Jürgen , Kessler Michael , Dunn Robert R. 
Published: March 2006

ABSTRACTAim  We studied pteridophyte species richness between 100 m and 3400 m along a Neotropical elevational gradient and tested competing hypotheses for patterns of species richness.Location  Elevational transects were situated at Volcán Barva in the Braulio Carrillo National Park and La Selva Biological Station (100–2800 m) and Cerro de la Muerte (2700–3400 m), both on the Atlantic slope of Costa Rica, Central America.Method  We analysed species richness on 156 plots of 20 × 20 m and measured temperature and humidity at four elevations (40, 650, 1800 and 2800 m). Species richness patterns were regressed against climatic variables (temperature, humidity, precipitation and actual evapotranspiration), regional species pool, area and predicted species number of a geometric null model (the mid‐domain effect, MDE).Results  The species richness of the 484 recorded species showed a hump‐shaped pattern with elevation with a richness peak at mid‐elevations (c. 1700 m). The MDE was the single most powerful explanatory variable in linear regression models, but species richness was also associated strongly with climatic variables, especially humidity and temperature. Area and species pool were associated less strongly with observed richness patterns.Main conclusions  Geometric models and climatic models exclusive of geometric constraints explained comparable amounts of the elevational variation in species richness. Discrimination between these two factor complexes is not possible based on model fits. While overall fits of geometric models were high, large‐ and small‐ranged species were explained by geometric models to different extents. Species with narrow elevational ranges clustered at both ends of the gradient to a greater extent than predicted by the MDE null models used here. While geometric models explained much of the pattern in species richness, we cannot rule out the role of climatic factors (or vice versa) because the predicted peak in richness from geometric models, the empirical peak in richness and the overlap in favourable environmental conditions all coincide at middle elevations. Mid‐elevations offer highest humidity and moderate temperatures, whereas at high elevations richness is reduced due to low temperatures, and at low elevations by reduced water availability due to high temperatures.
Clinical Characteristics of Tension‐Type Headache and Migraine in Adolescents: A Student‐Based Study
Authors: Karlı Necdet , Akgöz Semra , Zarifoğlu Mehmet , Akış Nalan , Erer Sevda 
Published: March 2006

Background and objectives.—Adolescent headaches, particularly migraine, might present with different features from adult headaches. The objectives of this study were to investigate the characteristics of tension‐type headache and migraine, to find the sensitivity and specificity of the diagnostic criteria of the IHS classification according to age and gender.Methods.—A multistep, stratified, cluster sampling method was used for subject selection. The estimated sample size was 2387. The study was conducted in two phases: the questionnaire and the face to face interview phases. During the semistructured interview, a clinical diagnosis has been made and clinical characteristics have been recorded.Results.—All headaches fulfilled the criteria of duration. The most common feature of migraine was moderate to severe (92.4%), pulsating pain (79.2%). For ETTH, bilateral localization (91.3%) and mild to moderate pain intensity (90.6%) were the most common features. Younger adolescents showed mixed headache characteristics. Highest sensitivities for migraine were duration (100%), moderate to severe pain (92.4%), and pulsating quality of pain (79.2%). Vomiting, trigger factors food and alcohol had a high specificity for migraine.Conclusions.—Our data strongly support continuum hypothesis. In early adolescence headaches might present with mixed headache characteristics. Age and gender have some influence on headache characteristics, particularly on migraine. The sensitivity and specificity of case definition criteria of ICHD‐2 for adolescent migraine is moderate and need to be reconsidered.
Characteristic and Overlapping Features of Migraine and Tension‐Type Headache
Authors: Turkdogan Dilsad , Cagirici Sultan , Soylemez Didem , Sur Haydar , Bilge Cevdet , Turk Ulku 
Published: March 2006

Objective.—This epidemiological survey was conducted to investigate comprehensive characteristic and overlapping features of migraine and tension‐type headache (TTH) disorders classified based on International Classification of Headache Disorders‐II.Methods.—The stratified cohort of this study was composed of 2504 schoolchildren aged 10 to 17 years. A 38‐item questionnaire inquiring all characteristic features of primary headache syndromes mandatory for classification was applied to selected 483 children with recurrent headache in the last 6 months.Results.—Migraine was diagnosed in 227 (47.0%) of 483 children and TTH in 154 (31.9%). Out of 125 children with definite migraine, 73 (58.4%) reported tension‐type symptoms and 94 (68.1%) of 138 children with definite TTH reported migraine‐type symptoms. Pressing pain (21%) and lack of aggravation of pain by physical activity (34%) were the major tension‐type features in patients with migraine. Throbbing quality (43%) and aggravation by physical activity (30%) determined the main migraine‐type features in patients with TTH.Conclusion.—The frequent co‐occurrence of migraine and TTH symptoms suggests the presence of a common pathogenesis.
Prevention of Migraine With Olmesartan in Patients With Hypertension/Prehypertension
Authors: Charles James A. , Jotkowitz Seymour , Byrd Lawrence H. 
Published: March 2006

Objective.—To explore the effects of olmesartan on frequency and severity of migraine attacks in patients with comorbid hypertension and prehypertension.Background.—A randomized, double‐blind, placebo‐controlled, crossover study with a total of 60 patients has demonstrated the efficacy and safety of the angiotensin II receptor blocker candesartan in migraine prophylaxis. We study the potential efficacy and tolerability of olmesartan in preventing migraine in patients with hypertension and prehypertension.Design/Methods.—Twenty‐four adults, aged 27 through 76, with either hypertension or prehypertension, were included in this open‐label study. Participants suffered from migraines (diagnosed according to International Headache Society classifications) for at least 3 months. Patients were treated with 10 to 40 mg of olmesartan per various observational periods of at least 3 months. Frequency and severity were recorded by office visits or by telephonic interview.Results.—Patients reported an 82.5% average reduction in the frequency of migraine attacks. Patients also experienced a 45% average reduction in the severity of migraine attacks measured on a numeric pain scale of 1 to 10. The only undesired effect was dizziness or presyncope. No serious adverse events occurred and no adverse event caused a premature termination. Two patients had no reduction in headache frequency, intensity, and blood pressure.Conclusions.—The favorable results and low rate of adverse effects, in this open migraine prevention study in patients with hypertension or prehypertension, are similar to results of the randomized, double‐blind, placebo‐controlled, crossover study in patients taking candesartan. Olmesartan shows a potential as an effective and well‐tolerated migraine prophylactic agent for patients with comorbid hypertension and prehypertension.
Assessment of Atrial Regional Wall Motion Using Strain Doppler Imaging During Biatrial Pacing in the Bradycardia‐Tachycardia Syndrome
Authors: MATSUMOTO KATSUMI , ISHIKAWA TOSHIYUKI , SUMITA SHINICHI , MATSUSHITA KOHEI , INOUE NORIKO , KOBAYASHI TSUKASA , UCHINO KAZUAKI , KIMURA KAZUO , UMEMURA SATOSHI 
Published: March 2006

Introduction: Biatrial pacing is expected to have preventive effects on atrial fibrillation.
Methods: We evaluated atrial regional wall motion by strain Doppler imaging (SDI) in 6 patients (62.5 ± 11.3 [SD] years), who suffered from atrial fibrillation, with an implanted biatrial pacemaker. SDI was performed and atrial regional wall motion was estimated during biatrial (BiA) and right atrial appendage (RAA) pacing.
Results: There was no significant difference in the interval from the pacing spike to the peak strain of the atrium in the lateral right atrium (LRA) between BiA and RAA pacing. However, there was a significant difference in the septal atrium (SA) between BiA and RAA pacing (225.0 ± 19.9 vs 267.2 ± 15.7 ms, P < 0.0001) and in the lateral left atrium (LLA) between BiA and RAA pacing (216.7 ± 21.6 vs 275.0 ± 16.2 ms, P < 0.0001). There were significant differences in the time difference of peak strain between BiA and RAA pacing in each atrial segment (LRA‐AS: 2.2 ± 5.9 vs 45.0 ± 11.9 ms, P = 0.0016, SA‐LLA: −8.3 ± 5.5 vs 7.8 ± 2.7 ms, P < 0.0011, LRA‐LLA: −6.1 ± 3.9 vs 52.8 ± 13.2 ms, P = 0.0002). There was no significant difference in the interval from the pacing spike to the inflection point of atrial strain (S‐I) of LRA. However, there were significant differences in S‐I of SA (83.9 ± 24.1 vs 129.9 ± 30.6 ms, P = 0.0086) and LLA (102.2 ± 37.9 vs 166.1 ± 13.4 ms, P = 0.0028).
Conclusion: BiA pacing improved the synchronicity of regional wall motion of both atrium.
Reduction of Right Ventricular Pacing in Patients with Dual‐Chamber ICDs
Authors: OLSHANSKY BRIAN , DAY JOHN , McGUIRE MAUREEN , HAHN STEPHEN , BROWN SCOTT , LEREW DARIN R. 
Published: March 2006

Background: Unnecessary right ventricular (RV) pacing in patients with implantable cardioverter defibrillators (ICD) may adversely affect heart failure morbidity and total mortality. Inhibition of Unnecessary RV Pacing with AV Search Hysteresis in ICDs (INTRINSIC RV) is a prospective, multicenter, randomized trial evaluating outcomes in ICD recipients programmed to single‐chamber pacing (VVI) versus dual‐chamber (DDDR) pacing with AV search hysteresis (AVSH).
Methods: Patients underwent ICD implant (for standard indications). The ICD was programmed to DDDR with AVSH regardless of any need for pacing. Rate‐adaptive pacing was set at 60–130 ppm with dynamic AV delay from 200 to 90 ms. AVSH was programmed to search every 32 intervals and extend the AV delay by 50%. One week post‐implant patients with ICDs were interrogated to assess the percentage of RV pacing with the expectation that most would have <20% RV pacing and would be randomized into INTRINSIC RV. Early analysis showed that targets for randomization were not met. AVSH parameters were modified under a protocol amendment to increase AV delay extension to 100%. We report findings related to this programming change based upon analyses of (nonrandomized) data pre‐ and post‐amendment.
Results: Twenty‐one percent of patients (n = 314) were enrolled pre‐amendment and 79% (n = 1,216) were enrolled post‐amendment. The mean percentage of RV pacing at the 1‐week visit was 41.4 ± 29.6% pre‐amendment and 14.7 ± 22.6% post‐amendment (P < 0.0001). The proportion of patients eligible for randomization (RV pacing <20% at the 1‐week visit) was 31.2% pre‐amendment and 76.8% post‐amendment (P < 0.0001).
Conclusion: AVSH can dramatically reduce the percentage of RV pacing among ICD recipients.