bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of sex and hormones on new cells in the developing rat hippocampus: a novel source of sex dimorphism?
Authors: Zhang Jian‐Min , Konkle Anne T. M. , Zup Susan L. , McCarthy Margaret M. 
Published: March 2008

AbstractThe hippocampus is a key brain region regulating complex cognitive and emotional responses, and is implicated in the etiology of depressive and anxiety disorders, many of which exhibit some degree of sex difference. The male rat hippocampus is consistently reported to be slightly but significantly larger than the female. The majority of studies on the development of volumetric sex differences have focused on the effects of estradiol (E2), with relatively few focusing on androgens. We examined the impact of both E2 and androgens on newly born cells in the developing rat hippocampus, and report that neonatal males have significantly more 5‐bromo‐2′‐deoxyuridine‐5′‐monophosphate (BrdU)+ cells than females. Both testosterone (T) and dihydrotestosterone treatment of females significantly increased the number of BrdU+ cells, an effect blocked by the androgen receptor antagonist, flutamide. However, only T significantly increased the number of neuronal nuclear antigen+ neurons in the female rat hippocampus. Interestingly, E2 treatment also increased BrdU+ cells in females, but had no effect on neuron number. Instead, E2 and T significantly increased the number of newly born glial fibrillary acidic protein or glutamine synthetase+ glial cells in females, indicating that androgens and E2 may act independently to achieve distinct endpoints. Quantification of pyknotic cells at two different developmental time points indicates no sex difference in the number of cells dying, suggesting, but not proving, that gonadal steroids are promoting cell genesis.
The neural dynamics of timed motor tasks: evidence from a synchronization–continuation paradigm
Authors: Serrien Deborah J. 
Published: March 2008

AbstractDistinct processing that integrates an accurate time scale is necessary for optimal motor behaviour. In the present study, corticocortical interactions as determined by EEG coherence were assessed in a synchronization–continuation paradigm during which subjects initially performed tapping movements in synchrony with external cues, followed by internal pacing of the target interval when the metronome was switched off. Unimanual and bimanual tasks were executed, and continuation of tapping was conducted with the same or different effector(s). The data showed an increased degree of mesial–central connectivity in the unpaced as compared to paced performance that was independent of task complexity, pointing to a general intensified demand of temporal processing when external cues are unavailable. When switching temporal information between effectors, coherence increased across the motor network. This increase depended upon preceding task complexity, and was most prominent for interhemispheric connections when performing unimanual tasks following bimanual pacing. Overall the data illustrate that timing of skilled actions can easily be transferred between effectors, although increased neural resources are required to conform to the temporal and motor constraints.
L‐type calcium channels are involved in fast endocytosis at the mouse neuromuscular junction
Authors: Perissinotti Paula P. , Tropper Bárbara Giugovaz , Uchitel Osvaldo D. 
Published: March 2008

AbstractWe used fluorescence microscopy of FM dyes‐labeled synaptic vesicles and electrophysiological recordings to examine the functional characteristics of vesicle recycling and study how different types of voltage‐dependent Ca2+ channels (VDCCs) regulate the coupling of exocytosis and endocytosis at mouse neuromuscular junction.Our results demonstrate the presence of at least two different pools of recycling vesicles: a high‐probability release pool (i.e. a fast destaining vesicle pool), which is preferentially loaded during the first 5 s (250 action potentials) at 50 Hz; and a low‐probability release pool (i.e. a slow destaining vesicle pool), which is loaded during prolonged stimulation and keeps on refilling after end of stimulation.Our results suggest that a fast recycling pool mediates neurotransmitter release when vesicle use is minimal (i.e. during brief high‐frequency stimulation), while vesicle mobilization from a reserve pool is the prevailing mechanism when the level of synaptic activity increases.We observed that specific N‐ and L‐type VDCC blockers had no effect on evoked transmitter release upon low‐frequency stimulation (5 Hz). However, at high‐frequency stimulation (50 Hz), L‐type Ca2+ channel blocker increased FM2‐10 destaining and at the same time diminished quantal release. Furthermore, when L‐type channels were blocked, FM2‐10 loading during stimulation was diminished, while the amount of endocytosis after stimulation was increased.Our experiments suggest that L‐type VDCCs promote endocytosis of synaptic vesicles, directing the newly formed vesicles to a high‐probability release pool where they compete against unused vesicles.
Electroconvulsive seizure restores neurogenesis and hippocampus‐dependent fear memory after disruption by irradiation
Authors: Warner‐Schmidt Jennifer L. , Madsen Torsten M. , Duman Ronald S. 
Published: March 2008

AbstractOngoing neurogenesis in the adult hippocampus is thought to play a role in learning and memory processes, and in response to antidepressant treatments. Low doses of irradiation (IRR) produce a significant long‐lasting inhibitory effect on hippocampal neurogenesis that correlates with long‐lasting behavioral deficits. Here we report that electroconvulsive seizure (ECS), which robustly increases adult neurogenesis in naïve animals, also reverses the disruption of neurogenesis produced by IRR exposure. Moreover, we find that vascular endothelial growth factor (VEGF) is an essential mediator of this effect. Expression of VEGF in the granule cell layer (GCL) of the hippocampus is decreased by IRR, and ECS administration reverses this deficit in VEGF. There is a corresponding alteration in the number of endothelial cells, which express VEGF, in the hippocampal GCL following IRR and ECS. We also find that blockade of VEGF signaling attenuates ECS‐induced proliferation, and VEGF infusion partially restores proliferation in irradiated animals. To examine the functional consequences of IRR and ECS on neurogenesis, hippocampus‐dependent contextual fear conditioning was assessed. We found that following disruption by IRR, ECS restores contextual learning to baseline levels at time points consistent with its effects on neurogenesis. These findings demonstrate that ECS, in part via induction of VEGF, can reverse long‐term neurogenesis deficits resulting from IRR, and that these effects have functional consequences on hippocampus‐dependent fear memory.
Forebrain dopamine depletion impairs motor behavior in lamprey
Authors: Thompson R. H. , Ménard A. , Pombal M. , Grillner S. 
Published: March 2008

AbstractThe structure of the basal ganglia appears to be conserved throughout vertebrate evolution, with characteristic cellular and transmitter components in each area, and the same types of afferent input. As described in rodents and primates, depletion of the striatal dopamine results in characteristic motor deficits. To explore if this role of the basal ganglia in modulating motor function was present early in vertebrate evolution, we investigated here the effects of striatal dopamine depletion in the lamprey, a cyclostome, which diverged from the main vertebrate line around 560 million years ago. The lamprey striatum contains the same cellular elements as found in mammals, and receives the same types of input, including a prominent dopamine innervation. We show here that MPTP (1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine; 100 mg/kg i.p.), a neurotoxin, depletes forebrain and striatal dopamine levels in lamprey to 15% of control values, and has profound effects on motor performance. Twenty‐four and 48 h after MPTP injection, lampreys demonstrated marked reductions in spontaneous swimming and the duration of each swimming episode. Impairments in the ability to initiate movements were shown by a decreased rate of initiation. Furthermore, the initiation and maintenance of locomotion induced by olfactory mucosa stimulation was severely impaired, as was the coordination of different motor tasks. These deficits were ameliorated by the dopamine agonist apomorphine. The motor deficits arising after striatal dopamine depletion are thus qualitatively similar in cyclostomes and mammals. The role of the dopamine innervation of the striatum thus appears to be conserved throughout vertebrate evolution.
Abundance and composition of ammonia‐oxidizing bacteria and ammonia‐oxidizing archaea communities of an alkaline sandy loam
Authors: Shen Ju‐pei , Zhang Li‐mei , Zhu Yong‐guan , Zhang Jia‐bao , He Ji‐zheng 
Published: March 2008

SummaryThe abundance and composition of soil ammonia‐oxidizing bacteria (AOB) and ammonia‐oxidizing archaea (AOA) communities under different long‐term (17 years) fertilization practices were investigated using real‐time polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE). A sandy loam with pH (H2O) ranging from 8.3 to 8.7 was sampled in years 2006 and 2007, including seven fertilization treatments of control without fertilizers (CK), those with combinations of fertilizer nitrogen (N), phosphorus (P) and potassium (K): NP, NK, PK and NPK, half chemical fertilizers NPK plus half organic manure (1/2OMN) and organic manure (OM). The highest bacterial amoA gene copy numbers were found in those treatments receiving N fertilizer. The archaeal amoA gene copy numbers ranging from 1.54 × 107 to 4.25 × 107 per gram of dry soil were significantly higher than those of bacterial amoA genes, ranging from 1.24 × 105 to 2.79 × 106 per gram of dry soil, which indicated a potential role of AOA in nitrification. Ammonia‐oxidizing bacteria abundance had significant correlations with soil pH and potential nitrification rates. Denaturing gradient gel electrophoresis patterns revealed that the fertilization resulted in an obvious change of the AOB community, while no significant change of the AOA community was observed among different treatments. Phylogenetic analysis showed a dominance of Nitrosospira‐like sequences, while three bands were affiliated with the Nitrosomonas genus. All AOA sequences fell within cluster S (soil origin) and cluster M (marine and sediment origin). These results suggest that long‐term fertilization had a significant impact on AOB abundance and composition, while minimal on AOA in the alkaline soil.
Changes in muscle, fat and bone mass after 36 weeks of maximal androgen blockade for prostate cancer
Authors: Galvão Daniel A. , Spry Nigel A. , Taaffe Dennis R. , Newton Robert U. , Stanley John , Shannon Tom , Rowling Chris , Prince Richard 
Published: March 2008

OBJECTIVETo assess the effects of androgen deprivation therapy (ADT) on whole‐body and regional muscle, fat and bone mass in men with prostate cancer without metastatic bone disease.PATIENTS AND METHODSSeventy‐two men aged 44–88 years underwent spine, hip and whole‐body dual‐energy X‐ray absorptiometry scans at baseline and after 36 weeks of ADT. The change in whole‐body and regional lean mass (LM), fat mass (FM), and bone mineral content and density (BMD) were determined. In addition, the prostate specific antigen (PSA), serum testosterone and haemoglobin levels were measured, and the level of physical activity and fatigue assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire‐30.RESULTSThe upper limb, lower limb, trunk and whole‐body LM decreased by a mean (sem) of 5.6 (0.6)%, 3.7 (0.5)%, 1.4 (0.5)% and 2.4 (0.4)% (P < 0.01), respectively, while FM increased by 20.7 (3.3)%, 18.7 (2.7)%, 12.0 (2.5)% and 13.8 (2.3)% (P < 0.001). Hip, spine, whole‐body and upper limb BMD decreased by 1.5 (0.5)%, 3.9 (0.4)%, 2.4 (0.3)% and 1.3 (0.3%) (P < 0.001), but not lower limb BMD. Serum testosterone, PSA and haemoglobin levels decreased by 93.3 (0.4)%, 98.2 (0.5)%, and 8.8 (0.9)% (P < 0.001), respectively. In addition, physical activity levels decreased and levels of fatigue increased.CONCLUSIONAfter 36 weeks of ADT there was a significant decrease in whole‐body and regional LM and bone mass, while whole‐body and regional FM increased in older men with prostate cancer. Strategies to counteract changes in soft tissue and bone mass during ADT should be formulated to minimize the risk of sarcopenia, osteoporosis and obesity.
Microsatellite analysis of allelic imbalance in tumour and blood from patients with prostate cancer
Authors: Schwarzenbach Heidi , Chun Felix K.‐H. , Müller Imke , Seidel Christoph , Urban Karoline , Erbersdobler Andreas , Huland Hartwig , Pantel Klaus , Friedrich Martin G. 
Published: March 2008

OBJECTIVETo investigate whether a high frequency of allelic imbalance (AI) is associated with clinicopathological variables of patients with prostate cancer.PATIENTS AND METHODSWe analysed loss of heterozygosity (LOH) and microsatellite (MS) instability (MSI) on circulating plasma DNA in a polymerase chain reaction (PCR)‐based MS study of 230 patients with prostate cancer and 43 with benign prostatic hyperplasia (BPH) using a panel of 13 polymorphic MS markers.RESULTSThe overall incidence of AI was significantly higher in primary tumours (34%) than in blood plasma samples from patients with prostate cancer (11%). Although LOH (2.0%) and MSI (1.5%) were also found in BPH plasma samples, their frequencies were low. AI identified in plasma samples from patients with prostate cancer could be retrieved in 63% of the paired tumour samples. The highest concordance of AI and retention of heterozygosity between tumour and plasma samples was 83% at the marker D8S360. There were high frequencies of LOH at the markers THRB, D7S522 and D8S137 in both types of specimens. The markers D11S898 and D11S1313 on the chromosome arm 11q showed frequent MSI. The comparison with established risk factors showed significant associations of an increase in prostate volume with AI at the combined markers D6S474/D7S522 in tumour tissues and at D7S522 in plasma samples (P < 0.04). In the primary tumours there was a further correlation of LOH at D11S1313 with increasing tPSA value (P = 0.005). The combination of total prostate‐specific antigen (PSA) and % free PSA was associated with LOH at THRB in plasma samples.CONCLUSIONSPlasma‐based MS analysis may have clinical value for the molecular staging of prostate cancer.
Hypermethylation of the thrombospondin‐1 gene is associated with poor prognosis in penile squamous cell carcinoma
Authors: Guerrero David , Guarch Rosa , Ojer Amaya , Casas Juan Manuel , Ropero Santiago , Mancha Ana , Pesce Carlo , Lloveras Belen , Garcia‐Bragado Federico , Puras Ana 
Published: March 2008

OBJECTIVETo evaluate the presence of human papillomavirus (HPV) infection, the methylation status in the promoter region of thrombospondin‐1 (TSP‐1), RAS association domain family 1A (RASSF1‐A) and p16 genes, and the expression of TSP‐1, CD31, p16 and p53 proteins in patients diagnosed with penile cancer, and the possible associations between these variables and clinical and pathological features.PATIENTS AND METHODSHPV types, gene promoter hypermethylation and protein expression were analysed by reverse line blot, methylation‐specific polymerase chain reaction, and immunohistochemistry, respectively, in 24 penile squamous cell carcinomas.RESULTSHPV infection was detected in 11 of 24 cases (46%), and TSP‐1, RASSF1‐A and p16 genes were hypermethylated in 46%, 42% and 38% of the tumours, respectively. TSP‐1 hypermethylation was associated with unfavourable histological grade (grade 3; P = 0.033), vascular invasion (P = 0.023), weak expression of TSP‐1 protein (P = 0.041), and shorter overall survival (P = 0.04). TSP‐1 expression was not associated with microvessel density. However, RASSF1‐A hypermethylation was more frequent in T1 tumours (P = 0.01), and p16 hypermethylation was not associated with any of the tested variables except for absence of p16 expression (P = 0.022).CONCLUSIONIn summary, the epigenetic inactivation of TSP‐1 and RASSF1‐A genes is associated with pathological variables and seems to be of prognostic significance in penile cancer.
Clusterin knockdown using the antisense oligonucleotide OGX‐011 re‐sensitizes docetaxel‐refractory prostate cancer PC‐3 cells to chemotherapy
Authors: Sowery Richard D. , Hadaschik Boris A. , So Alan I. , Zoubeidi Amina , Fazli Ladan , Hurtado‐Coll Antonio , Gleave Martin E. 
Published: March 2008

OBJECTIVESTo characterize changes in secretory clusterin (sCLU) expression in prostate cancer cells after treatment with docetaxel and to determine whether sCLU knockdown can re‐introduce chemosensitivity in a docetaxel‐resistant, androgen‐independent human prostate cancer model.PATIENTS AND METHODSA tissue microarray was constructed for 84 radical prostatectomy (RP) specimens from a multicentre Phase II trial of neoadjuvant combined androgen ablation and docetaxel (CUOG‐P01a) and assessed for changes in the expression of the cytoprotective chaperone sCLU. The human prostate cancer cell line PC‐3 was repeatedly exposed to docetaxel chemotherapyin vitro, and a docetaxel‐resistant cell subline (PC‐3dR) was developed and analysed.RESULTSsCLU levels were significantly higher in RP specimens treated with neoadjuvant combined androgen ablation and docetaxel than in untreated specimens. Similarly, sCLU expression increased 2.5‐fold in the newly developed docetaxel‐refractory PC‐3dR cell line compared with parental PC‐3 cells. There was a dose‐dependent and sequence‐specific decrease in sCLU levels in PC‐3dR cells using OGX‐011, an antisense oligonucleotide against human sCLU. OGX‐011 and small‐interference RNA both chemosensitized PC‐3dR cells to docetaxel and mitoxantronein vitroand apoptotic rates in PC‐3dR cells were significantly increased when OGX‐011 was combined with docetaxel.In vivo,growth of PC‐3dR xenografts in nude mice was synergistically inhibited by OGX‐011 combined with paclitaxel or mitoxantrone (by 76% and 44% compared with their mismatch controls, respectively).CONCLUSIONThe present findings indicate that targeted knockdown of sCLU enhances the effects of cytotoxic chemotherapy in docetaxel‐refractory cells, and provide preclinical proof of principle for clinical trials testing OGX‐011 in second‐line chemotherapy regimens for patients with docetaxel‐refractory prostate cancer.
Confronting complexity: insights from the details of behavior over multiple timescales
Authors: Samuelson Larissa K. , Horst Jessica S. 
Published: March 2008

AbstractYoung children tend to generalize novel names for novel solid objects by similarity in shape, a phenomenon dubbed ‘the shape bias’. We believe that the critical insights needed to explain the shape bias in particular, and cognitive development more generally, come from Dynamic Systems Theory. We present two examples of recent work focusing on the real‐time decision processes that underlie performance in the tasks used to measure the shape bias. We show how this work, and the dynamic systems perspective, sheds light on the controversy over the origins and development of the shape bias. In addition, we suggest that this dynamic systems perspective provides the right level for explanations of development because it requires a focus on the details of behavior over multiple timescales.
Young children's spontaneous use of geometry in maps
Authors: Shusterman Anna , Ah Lee Sang , Spelke Elizabeth S. 
Published: March 2008

AbstractTwo experiments tested whether 4‐year‐old children extract and use geometric information in simple maps without task instruction or feedback. Children saw maps depicting an arrangement of three containers and were asked to place an object into a container designated on the map. In Experiment 1, one of the three locations on the map and the array was distinct and therefore served as a landmark; in Experiment 2, only angle, distance and sense information specified the target container. Children in both experiments used information for distance and angle, but not sense, showing signature error patterns found in adults. Children thus show early, spontaneously developing abilities to detect geometric correspondences between three‐dimensional layouts and two‐dimensional maps, and they use these correspondences to guide navigation. These findings begin to chart the nature and limits of the use of core geometry in a uniquely human, symbolic task.
Verbal self‐instructions in task switching: a compensatory tool for action‐control deficits in childhood and old age?
Authors: Kray Jutta , Eber Jutta , Karbach Julia 
Published: March 2008

AbstractThis study examined the influence of verbal self‐instructions on age differences in task switching. Task‐switching ability, measured as the difference between performance in single‐task blocks and in mixed‐task blocks in which participants switch between two tasks (mixing costs), increases during childhood and decreases in old age. To measure the influence of language on task switching, we compared conditions in which participants either (a) named the next task to be performed (i.e. task‐relevant verbalization), (b) verbalized words not related to the task at hand (i.e. task‐irrelevant verbalization), or (c) did not verbalize (control condition). Results indicated that mixing costs were substantially reduced under task‐relevant verbalization and increased under task‐irrelevant verbalization. Moreover, age‐related differences in mixing costs were increased when the use of inner speech was disrupted and were reduced when participants performed task‐relevant verbalization. These findings suggest that verbal self‐instructions are a useful tool for retrieving the next task goal and for reducing action‐control deficits in younger children and older adults.
Functional neuroimaging of speech perception during a pivotal period in language acquisition
Authors: Redcay Elizabeth , Haist Frank , Courchesne Eric 
Published: March 2008

AbstractA pivotal period in the development of language occurs in the second year of life, when language comprehension undergoes rapid acceleration. However, the brain bases of these advances remain speculative as there is currently no functional magnetic resonance imaging (fMRI) data from healthy, typically developing toddlers at this age. We investigated the neural basis of speech comprehension in this critical age period by measuring fMRI activity during passive speech comprehension in 10 toddlers (mean ± SD; 21 ± 4 mo) and 10 3‐year‐old children (39 ± 3 mo) during natural sleep. During sleep, the children were presented passages of forward and backward speech in 20‐second blocks separated by 20‐second periods of no sound presentation. Toddlers produced significantly greater activation in frontal, occipital, and cerebellar regions than 3‐year‐old children in response to forward speech. Our results suggest that rapid language acquisition during the second year of life may require the utilization of frontal, cerebellar, and occipital regions in addition to classical superior temporal language areas. These findings are consistent with the interactive specialization hypothesis, which proposes that cognitive abilities develop from the interaction of brain regions that include and extend beyond those used in the adult brain.