bluuebunny/crossref_metadata_2025 huggingface dataset:
Communal Roost Site Selection in a Neotropical Harvestman: Habitat Limitation vs. Tradition
Authors: Grether Gregory F. , Donaldson Zoe R.
Published: February 2007

Many species have been reported to form roosting (resting, sleeping) aggregations at ‘traditional’ sites, but the alternative hypothesis that specific sites are used repeatedly because of habitat limitation is rarely tested. We studied the roosting behavior of a species of harvestman (Opiliones, Prionostemma sp.) at a lowland rainforest site in Nicaragua. Both sexes roosted by day in spiny palm trees, dispersed at dusk to forage, and rejoined aggregations just before dawn. The distribution of harvestmen among spiny palms was significantly clumped, and harvestman density did not correlate with spiny palm density. Aggregations formed repeatedly in a small subset of the available spiny palms and the same sites were used in two different years (2001, 2003). Nevertheless, the membership of aggregations was fluid; individual harvestmen were found at multiple roosts and moved up to 0.2 km per night. Translocated animals often returned to the roost where they had been released or nearby roosts but were never found at previously unused sites. The high consistency of site use but low site fidelity of individuals suggests that roost sites differed conspicuously (to the harvestmen) from sites that were not used. We found no univariate or multivariate differences between used and unused sites, however, in the characteristics of the trees or microclimate. These results conflict with the habitat limitation hypothesis but are consistent with the traditional site use hypothesis. The tradition may be mediated by a site‐labeling chemical, a mechanism that does not require individual site fidelity. We discuss these results in relation to the proposed functions of roosting aggregations.
Effect of Various Degrees of Dystocia in Dairy Cattle on Calf Viability, Milk Production, Fertility and Culling
Authors: Tenhagen B.‐A. , Helmbold A. , Heuwieser W.
Published: February 2007

The objective of this study was to analyse the effect of dystocia on calf viability, milk production, fertility and culling under field (farm) conditions in a retrospective case–control study. A total of 253 calvings that were attended by a veterinarian were classified into three categories: mild dystocia (MD), severe dystocia (SD) and caesarean section (CS). For every case of dystocia, a control was chosen from the same farm and matched for calving month, breed and parity. Cases and controls were compared concerning calf viability, milk production, fertility and culling. The proportion of stillbirths was significantly higher in cows with dystocia compared with their controls. However, the difference was lower in CS cows than in the other two groups. MD had no significant effects on milk production, fertility and culling. There were no obvious effects of SD on monthly test day milk production, while CS cows produced significantly less milk than their controls. Compared with controls, less SD (50.0% versus 61.6%) and CS cows (48.6% versus 70.3%) conceived until 200 days in milk and more CS cows (31.1% versus 16.2%) were culled in the same time interval. These data demonstrate the scope of economic and animal welfare opportunities associated with the reduction of dystocia by management and breeding.
Pneumonia Disease Assessment using a Slaughterhouse Lung‐Scoring Method
Authors: Ostanello F. , Dottori M. , Gusmara C. , Leotti G. , Sala V.
Published: February 2007

The aims of this study were the evaluation of a quantitative method for the assessment of pneumonia lesions applied to heavy‐weight slaughtered pigs, the identification of risk factors connected with the increase in the prevalence and severity of the lesions and the evaluation of a possible correlation between the presence of pneumonia lesions and the decrease in the carcass quality. The lungs of 10 041 pigs (109 slaughtered batches) coming from 91 farms located in Northern Italy were examined. Lung lesions were scored using the method developed byMadec and Kobisch (Journ. Rech. Porc. Fr.,14, 1982, 405). Before the scoring, anamnestic information regarding the farm of origin of each batch were collected. For 41 batches (3603 pigs), information about carcass quality were also collected. Pneumonia lesions were found in 59.6% of the lungs (range 3–91%), and the average batch score was 2.11 (range 0.03–7.15). We identified as farm risk factors those related to an increase in the severity of the lung lesions, the presence of breeders within the herd, the starting of a growing cycle during the winter season and the lack of vaccination programmes toMycoplasma hyopneumoniae. Moreover, we also found a statistically significant association between the increase in the mean lung score of the batch and the decrease of the carcass quality.
Effects of temporal variation of the seaweed Caulerpa prolifera cover on the associated crustacean community
Authors: Emilio Sánchez‐Moyano Juan , García‐Asencio Isabel , Carlos García‐Gómez José
Published: February 2007

The aim of this study was to establish the effect of temporal variation of the alga Caulerpa prolifera cover on the composition and stability of the associated crustacean community. Forty‐five crustacean species were found, amphipods and tanaidaceans being the most abundant groups. The stations were grouped mainly based on the gradient of algal cover, independently of location or sampling period (MDS analyses). Considering separately epifaunal and infaunal species, the epifauna occurred mainly at high cover (HC) and medium–low cover (MLC) stations, while the infauna occurred at MLC and unvegetated (UV) stations. Infaunal species were predominant in all stations and sampling periods, and the abundance and numbers of epifaunal species showed a clear dependence of algal cover. To quantify the loss of biodiversity due to the plant cover variations, we applied the average and variation in taxonomic distinctness (Δ+ and Λ+, respectively). The HC stations, especially those with fewer algal cover variations along the study period, showed few fluctuations of Δ+,and Λ+ was usually located near mean; however, UV stations tended to fall in the area where the statistical power of the test is reduced and showed more oscillations of Λ+. The ability of these indices to test the fauna composition in function of the alga presence is discussed.
Cold‐seep assemblages on a giant pockmark off West Africa: spatial patterns and environmental control
Authors: Olu‐Le Roy K. , Caprais J.‐C. , Fifis A. , Fabri M.‐C. , Galéron J. , Budzinsky H. , Le Ménach K. , Khripounoff A. , Ondréas H. , Sibuet M.
Published: February 2007

A giant pockmark colonised by dense cold‐seep assemblages near 3160 m depth along the Congo‐Angola margin has been surveyed by the ROV Victor 6000. The quantitative distribution of chemosynthetic communities was mapped along the dive tracks from a video study using GIS and image mosaicking. Several types of faunal assemblages, either dominated by bivalves of the families Mytilidae (Bathymodiolus sp.) or Vesicomyidae (Calyptogena sp., ‘Vesicomya’ aff. chuni), or by Siboglinidae polychaetes (Escarpia southwardae) were mapped over the 800‐m diameter pockmark area and sampled for fauna, water and sediment. The isotopic analyses (δ13C) of tissues from symbiont‐bearing species were within the range typical of nutrition via symbiosis using methane for mussels and sulphide for vesicomyids and siboglinids. The living chemosynthetic communities were distributed on a SW‐NE axis, corresponding to the expression at the sediment surface of a main buried channel providing fluids to the pockmark. The site was characterised by a more active central part in a depression with abundant carbonate concretions where high‐density clusters of siboglinids and mytilids dominate. Large fields of dead and live vesicomyids with a lower mean density were observed in the external areas. The mean coverage of each of the three symbiotic taxa in these two contrasted areas was estimated from mosaic analysis and was up to 30% in the central area dominated by E. southwardae bushes (23%). Symbiont‐bearing species distribution was consistent with methane concentrations in seawater that were generally higher in mytilid beds than in the vicinity of siboglinids and vesicomyids. A Principal Component Analysis performed on environmental factors at the ten sampling sites revealed that 37% of the observed variance in the distribution of symbiont‐bearing species may be explained by variation in both methane and oxygen concentrations, while a Canonical Redundancy Analysis selected methane concentration as the only variable which explains symbiont‐bearing species densities. This spatial distribution of chemosynthetic species at the pockmark scale may reflect temporal patterns of succession of both substrate and fauna, and may be related to different individual pockmarks visible on the microbathymetry mapped using ROV data.
Exploiting natural genetic diversity and mutant resources of Arabidopsis thaliana to study the A. thaliana–Plasmodiophora brassicae interaction
Authors: Alix K. , Lariagon C. , Delourme R. , Manzanares‐Dauleux M. J.
Published: February 2007

Clubroot, caused by the obligate biotroph Plasmodiophora brassicae Woron., is one of the most damaging diseases of Brassica crops in the world. Because the pathogen can infect all the Brassicaceae, including Arabidopsis thaliana, possible advantages have been found by identifying sources of resistance to P. brassicae in this model plant. Fifty‐seven ecotypes of A. thaliana, including the INRA Arabidopsis core collection, were assessed for resistance to clubroot disease. Ecotypes Burren (Bur‐0), Tsu (Tsu‐0) and Kaunas (Kn − 0) were identified as partially resistant to P. brassicae isolates eH and/or Ms6. Fifteen Arabidopsis mutant lines known for certain physiological processes potentially involved in the host‐pathogen interaction were evaluated for their resistance/susceptibility to P. brassicae. Mutant axr3‐1 appeared to be less susceptible than the wild type Columbia, supporting the hypothesis of the involvement of the auxin pathway in the development of clubs.
Prospects of breeding biofortified pearl millet with high grain iron and zinc content
Authors: Velu G. , Rai K. N. , Muralidharan V. , Kulkarni V. N. , Longvah T. , Raveendran T. S.
Published: February 2007

Development of crop cultivars with elevated levels of micronutrients is being increasingly recognized as one of the approaches to provide sustainable solutions to various health problems associated with micronutrient malnutrition, especially in developing countries. To assess the prospects of this approach in pearl millet (Pennisetum glaucum), a diverse range of genetic materials, consisting of 40 hybrid parents, 30 each of population progenies and improved populations, and 20 germplasm accessions, was analysed for grain iron (Fe) and zinc (Zn) content, deficiencies of which adversely affect human health. Based on the mean performance in two seasons at ICRISAT, Patancheru, India, large variability among the entries was found, both for Fe (30.1–75.7 mg/kg on dry weight basis) and Zn (24.5–64.8 mg/kg). The highest levels of grain Fe and Zn were observed in well‐adapted commercial varieties and their progenies, and in the parental lines of hybrids, which were either entirely based on iniari germplasm, or had large components of it in their parentage. There were indications of large within‐population genetic variability for both Fe and Zn. The correlation between Fe and Zn content was positive and highly significant (r = 0.84; P < 0.01). These results indicate that there are good prospects of simultaneous selection for both micronutrients, and that selection within populations, especially those with the predominantly iniari germplasm, is likely to provide good opportunities for developing pearl millet varieties and hybrid parents with significantly improved grain Fe and Zn content in pearl millet.
Development, characterization and utilization of microsatellite markers in pigeonpea
Authors: Odeny D. A. , Jayashree B. , Ferguson M. , Hoisington D. , Crouch J. , Gebhardt C.
Published: February 2007

Pigeonpea is a major legume of the semi‐arid tropics that has been neglected in terms of molecular breeding. The objectives of this study were to develop microsatellite markers and evaluate their potential for use in pigeonpea genetics and breeding. Two hundred and eight microsatellite loci were isolated by screening a non‐enriched partial genomic library. Primers were designed for 39 microsatellite loci, 20 of which amplified polymerase chain reaction products of the expected size. Nineteen of the primer pairs were polymorphic amongst 15 cultivated and nine wild pigeonpea accessions providing evidence for cross‐species transferability within the genus Cajanus. A total of 98 alleles were detected at the 19 polymorphic loci with an average of 4.9 alleles per locus. The observed heterozygosity ranged from 0.17 to 0.80 with a mean of 0.42 per locus. Less allelic variation (31 alleles) was observed within the cultivated species than across the wild species (92 alleles). The diversity analysis readily distinguished all wild relatives from each other and from the cultivated germplasm. Development of more microsatellites is recommended for future genomic studies in pigeonpea.
Comparative study of the discriminating capacity and effectiveness of AFLP, STMS and EST markers in assessing genetic relationships among evergreen azaleas
Authors: Scariot V. , De Keyser E. , Handa T. , De Riek J.
Published: February 2007

The application of amplified fragment length polymorphism (AFLP), sequence tagged microsatellite site (STMS) and expressed sequence tag (EST) markers to study the genetic relationships in an evergreen azalea gene pool was investigated. STMS and EST markers revealed a higher genetic distance detection capacity than AFLPs, which, nevertheless, were the most efficient marker system due to their highest polymorphism detection capacity. Similarity matrices showed weak, yet significant, correlations when Mantel's test was applied. To assess the usefulness of the overall information provided by these marker data for establishing phylogenetic relationships and horticultural classification, cluster analysis was performed. The joint AFLP, STMS and EST data were demonstrated to be remarkably effective for group discrimination and phylogenetic studies. The use of these polymerase chain reaction marker systems is discussed in terms of the choice of appropriate marker techniques for different aspects of evergreen azalea germplasm evaluation.
How to use medicines in children: Principles of paediatric clinical pharmacology
Authors: Sinha Yashwant , Cranswick Noel E
Published: February 2007

Abstract:  Knowledge of drug administration in children and infants has significantly lagged behind that of adults. Despite several paediatric therapeutic mishaps that have been a catalyst for major regulatory reform, the majority of registered medicines do not have indications or dosing for children. This paper will briefly summarise key issues in paediatric pharmacology, including differences in prescribing for children, off‐label and unlicensed prescribing and conduct of paediatric clinical trials. A particular emphasis will placed on the situation in Australia.
Prescribing safely for children
Authors: Sinha Yashwant , Cranswick Noel E
Published: February 2007

Abstract:  This paper is the second in a series of two and will attempt to highlight important issues in prescribing for children, including principles of safe prescribing, adverse drug reaction assessment and common drugs including paracetamol and ibuprofen. A list of drug information resources is included, which may be useful for clinicians.
Indigenous child oral health at a regional and state level
Authors: Jamieson Lisa M , Parker Eleanor J , Armfield Jason M
Published: February 2007

Aim:  To compare the dental disease experience of Indigenous and non‐Indigenous children in South Australia’s mid‐north region (regional area) and to assess Indigenous oral health differences at a regional‐ and state‐level.

Methods:  Data were collected from a School Dental Service based in an Aboriginal‐owned medical health service and standard school dental clinics in the regional area from March 2001 to March 2006. State‐level data were obtained over a 12‐month period in 2003. Caries prevalence (per cent dmft or DMFT >0) and severity (mean dmft or DMFT, SiC and SiC10) measures were used to assess dental disease experience.

Results:  In the regional area, Indigenous children aged <10 years had 1.6, 1.9, 1.6 and 1.4 times the percent dmft >0, mean dmft, SiC primary and SiC10 primary, respectively, of their non‐Indigenous counterparts, while Indigenous children aged 6+ years had 1.3, 1.7, 1.7 and 1.6 times the percent DMFT > 0, mean DMFT, SiC permanent and SiC10 permanent, respectively, of non‐Indigenous children. Indigenous children in the regional area had significantly higher caries prevalence and severity than Indigenous children at a state‐level.

Conclusion:  Indigenous children in South Australia’s mid‐north region are dentally disadvantaged in comparison with their non‐Indigenous counterparts and with the general South Australian Indigenous child population.
Comparison of mental health symptoms between children attending developmental/behavioural paediatric clinics and child and adolescent mental health service
Authors: Roongpraiwan Rawiwan , Efron Daryl , Sewell Jill , Mathai John
Published: February 2007

Aim: Australian paediatricians are being referred many children with severe and complex behavioural presentations. Australian paediatricians are being referred many children with severe and complex behavioural presentations. The aim of this study was to compare patients seen in the developmental/behavioural paediatric clinic (DBP) with those seen in the community child and adolescent mental health service (CAMHS) of a paediatric teaching hospital. We hypothesised that the burden of emotional‐behavioural symptoms of children referred to these two services would be similar.

Method: The Strengths and Difficulties Questionnaire was completed by parents of children seen in both the DBP and the CAMHS of a paediatric teaching hospital over a 6‐month period. The self‐report version was completed by patients aged over 11 years. Data were compared both continuously and categorically, for total scores and subscale scores.

Results: For patients aged 4–10 years, the total scores were higher for the CAMHS (mean = 20.4) than the DBP (mean = 16.6) sample (P < 0.001). For patients aged 11–17 years, there was no difference between the groups in either the parent report total scores (CAMHS 19.4; DBP 19.3,P = 0.92) or the self‐report total scores (CAMHS 17.5; DBP 15.7,P = 0.11).

Conclusion: Children referred to a DBP clinic had a comparable burden of emotional/behavioural symptoms to those referred to a CAMHS service, although the degree of impairment was higher in the CAMHS sample. The complexity and severity of clinical work undertaken in DBP services needs to be taken into account in paediatric training, and in the broad planning of child and adolescent mental health service delivery.
Occurrence and management of acute respiratory illnesses in early childhood
Authors: Kusel Merci MH , De Klerk Nicholas , Holt Patrick G , Landau Louis I , Sly Peter D
Published: February 2007

Aim:  Acute respiratory illnesses (ARI) impose massive economic burden on health services. The growing costs, limited benefits of pharmacotherapeutic agents, and alarming rise in antibiotic resistance poses a major health challenge. Analysis of the nature and burden of ARI through well‐designed epidemiologic studies will help in the development of a uniform public health approach to identify methods to reduce disease transmission and maximise prevention strategies. The aim of this study was to analyse the nature and magnitude of the burden of ARI encountered by a cohort of children in the first 5 years of life.

Methods:  This community‐based prospective study of ARI followed a cohort of children from birth until 5 years of age. Information on all episodes of ARI encountered, and their management, was collected through daily symptom diary and fortnightly telephone calls.

Results:  Four episodes of ARI/year were reported in the first 2 years and 2–3 episodes/year between 2 and 5 years. The majority were upper respiratory infections. 53% had at least one lower respiratory infection in the first year. For the majority, symptoms lasted 1–2 weeks. 53% were treated with antitussives or cough mixtures, 44% with paracetamol and 23% with antibiotics. A total of 46% of the episodes presented to a family physician, with younger children and those with lower respiratory infection more likely to seek attention.

Conclusion:  ARI are common in childhood and although symptoms may last for 4 weeks, the majority resolve spontaneously. Use of medication does not appear to significantly alter the course or duration of symptoms of ARI.
Survival by ethnicity for children diagnosed with cancer in New Zealand during 1990–1993
Authors: Douglas Nicholas M , Dockerty John D
Published: February 2007

Aim: This study aimed to assess survival by ethnicity for all New Zealand children (0–14 years) diagnosed with cancer during 1990–1993 and second, to determine the accuracy of the children’s routinely collected ethnicity information.

Methods: Four hundred and nine children were followed up using two largely independent sources. We compared survival using the Cox model.

Results: Maori and Pacific Island children had the same survival as non‐Maori/non‐Pacific children for ‘all cancers combined’ (hazard ratios (HR): 0.98; 95% confidence interval (CI): 0.64–1.50 and 1.01; 95% CI: 0.53–1.89 respectively) and acute lymphoblastic leukaemia (HR: 1.09; 95% CI: 0.45–2.62 and 0.99; 95% CI: 0.24–4.16, respectively). The ethnicity data stored within the National Health Index and the New Zealand Cancer Registry showed reasonably close agreement with ethnicity data provided by the children’s mothers at interview (Kappa statistics: 0.82 and 0.81 respectively) while the Mortality Collection showed only moderate agreement (Kappa statistic: 0.63).

Conclusion: The point estimates in this study provide no evidence of ethnic disparities in survival from childhood cancer in New Zealand. However, even in this national study there were small numbers of Maori and Pacific children leading to wide confidence intervals. We therefore recommend cautious interpretation.
Encephalopathy after furosemide use in nephrotic syndrome
Authors: Sharma Ajay P , Grimmer Joanne
Published: February 2007

Abstract:  An 18‐year‐old girl with nephrotic syndrome presented with a life‐threatening respiratory failure and a severe encephalopathy, shortly after being started on furosemide. The evaluation confirmed furosemide as the sole culprit for the clinical manifestations. This case highlights an unpredictable dose–response relationship of furosemide. The pathophysiological basis, differential diagnosis and clinical implications of the observed findings are discussed.
Antisperm antibodies in infertile men and their correlation with seminal parameters
Authors: GARCIA PATRICIA C. , RUBIO ELIANA M. , PEREIRA ODUVALDO C.M.
Published: February 2007

Aim:  Antisperm antibodies (ASA) in males cause the autoimmune disease ‘immune infertility’. The present study intended to detect the presence of ASA and their incidence in men with unexplained infertility, as well as to evaluate the correlation between the presence of ASA and semen parameter alterations.

Methods:  Blood and sperm assessment were collected to carry out a direct and indirect mixed antiglobulin reaction (MAR) test and semen analysis in infertile and fertile men from the University Hospital of the Faculty of Medicine, Sao Paulo State University, Sao Paulo.

Results:  In the MAR test, 18.18% of infertile men were positive for ASA. In fertile men, no positivity was found. A significant correlation between the presence of ASA with an increased white blood cell count plus a decreased hypoosmotic swelling test result was observed.

Conclusions:  The results indicate that ASA are involved in reduced fertility. It is not ASA detection per se that provides conclusive information about the occurrence of damage to fertility. The correlation between infertility and altered seminal parameters reinforce the ASA participation in this pathology. (Reprod Med Biol 2007; 6: 33–38)
Estrogen to progesterone ratio affects hormonal and lipid follicular fluid profiles in dairy cows
Authors: RENAVILLE BENEDICTE , COMIN ANTONELLA , FAZZINI UBERTO , MARCHINI ELENA , MAIERO STEFANO , MARCHI VITTORIO , PRANDI ALBERTO
Published: February 2007

Aim:  The present study described hormonal and lipids concentrations of follicles that develop under high progesterone plasmatic levels, mimicking the second follicular wave.

Methods:  All follicles were removed by aspiration in order to generate a new follicular wave. Follicular fluid was then obtained from either 3 day old follicles (F3) or 6 day old follicles (F6). This experimental protocol was carried out at 20 days and 90 days post‐partum on Frisian dairy cows that had already returned to cyclicity.

Results:  Estrogen active follicles (ratio of estrogen to progesterone in follicular fluid higher than 1) have higher levels of VEGF, IGF‐I and linoleic acid, and have lower levels of NEFA, oleic and arachidonic acid. Non‐estrogen active follicular fluid concentrations of IGF‐I and NEFA were similar to plasma concentrations. In contrast, estrogen active follicles showed higher IGF‐I and lower NEFA levels than plasmatic ones that could be used to sustain follicular growth.

Conclusions:  The results show that estrogen active follicles might have their own metabolism. (Reprod Med Biol 2007; 6: 45–51)
Clinical outcomes of two different endometrial preparation methods for cryopreserved‐thawed embryo transfer in patients with a normal menstrual cycle
Authors: KAWAMURA TOSHIHIRO , MOTOYAMA HIROSHI , YANAIHARA ATSUSHI , YORIMITSU TAKESHI , ARICHI AKANE , KARASAWA YASUHIRO , SUGA KAHORI , MIYA KAORU , ISHIKAWA SEIKA , MIZUSHIMA SHIHO , KAWAMURA MAKIKO
Published: February 2007

Aim:  To compare the clinical outcomes of cryopreserved‐thawed embryo transfer among patients with a normal menstrual cycle who had natural or hormone‐replacement cycles.

Methods:  From January 2004 to June 2006, cryopreserved embryos following conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) were thawed and transferred in a total of 720 natural cycles and 136 hormone‐replacement cycles.

Results:  Cryopreserved‐thawed embryo transfer in patients who had a natural or hormone‐replacement cycle resulted in clinical pregnancy in 43.1% and 40.4%, respectively; a rate of miscarriage of 14.5% and 23.6%, respectively; and a rate of ongoing pregnancy and delivery of 36.5% and 30.9%, respectively. None of these differences were statistically significant.

Conclusions:   Patients with a normal menstrual cycle who have natural or hormone‐replacement cycles can be expected to have comparable clinical outcomes with cryopreserved‐thawed embryo transfer. (Reprod Med Biol 2007; 6: 53–57)
Importance of early lighting conditions in maternal care by dam as well as anxiety and memory later in life of offspring
Authors: Toki Shigeru , Morinobu Shigeru , Imanaka Akihiro , Yamamoto Shigeto , Yamawaki Shigeto , Honma Ken‐ichi
Published: February 2007

Rodent studies have revealed that the early rearing environment plays an important role in the development of stress vulnerability, memory and cognition. Although early lighting conditions (ELC) are involved in these neuronal developments through both maternal and offspring behavior, their influence has not been fully elucidated. Thus, by using Sprague‐Dawley rats, we examined whether ELC affected maternal care by the dam and the subsequent neurodevelopment of the offspring. Prolonged dark phase conditions (PDC) (light/dark, 6/18 h) and prolonged light phase conditions (light/dark, 18/6 h) were administered from postnatal day 2 to postnatal day 14. Throughout this period, maternal care and the circadian rhythmicity of dams were investigated. In adolescence and adulthood of the offspring, we measured anxiety‐like behavior, social interaction, object recognition memory, activity rhythm and corticosterone response to stress with hippocampal expression of N‐methyl‐d‐aspartate and glucocorticoid receptor mRNAs. PDC altered maternal care and circadian rhythmicity in the dam compared with normal lighting conditions and prolonged light phase conditions. PDC markedly increased anxiety‐like behavior, decreased social interaction and object recognition memory, and inhibited corticosterone feedback in offspring later in life. Furthermore, hippocampal levels of glucocorticoid receptor mRNA and N‐methyl‐d‐aspartate receptor 2B mRNA in rats subjected to PDC were significantly lower than in animals subjected to normal lighting conditions. In the adult offspring, the circadian rhythm of locomotor activity was not affected. These findings suggested that ELC affect mother–infant interactions and subsequently at least partially alter the neurobehavioral development of offspring.
Microglia‐derived interleukin‐6 and leukaemia inhibitory factor promote astrocytic differentiation of neural stem/progenitor cells
Authors: Nakanishi Masaya , Niidome Tetsuhiro , Matsuda Satoru , Akaike Akinori , Kihara Takeshi , Sugimoto Hachiro
Published: February 2007

Neural stem/progenitor cells (NSPCs) proliferate and differentiate depending on their intrinsic properties and local environment. It has been recognized that astrocytes promote neurogenic differentiation of NSPCs, suggesting the importance of cell–cell interactions between glial cells and NSPCs. Recent studies have demonstrated that microglia, one type of glial cells, play an important role in neurogenesis. However, little is known about how activated microglia control the proliferation and differentiation of NSPCs. In this study, we investigated the possibility that microglia‐derived soluble factors regulate the behaviour of NSPCs. To this end, NSPCs and microglial cultures were obtained from rat embryonic day 16 subventricular zone (SVZ) and rat postnatal 1 day cortex, respectively, and the conditioned medium from microglia was prepared. Microglial‐conditioned medium had no significant effect on the proliferation of NSPCs. In contrast, it increased the percentage of cells positive for a marker of astrocytes, glial fibrillary acidic protein (GFAP) during differentiation. The induction of astrocytic differentiation by microglial‐conditioned medium was reduced by the inhibition of the Janus kinase/signal transducer and activation of transcription (JAK/STAT) and mitogen‐activated protein kinase (MAPK) pathways. Furthermore, microglia‐derived interleukin (IL)‐6 and leukaemia inhibitory factor (LIF) were identified as essential molecules for this astrocytic differentiation using neutralizing antibodies and recombinant cytokines. Our results suggest that microglia as well as astrocytes contribute to the integrity of the local environment of NSPCs, and at least IL‐6 and LIF released by activated microglia promote astrocytic differentiation of NSPCs via the activation of the JAK/STAT and MAPK pathways.
Impaired spatial working memory but spared spatial reference memory following functional loss of NMDA receptors in the dentate gyrus
Authors: Niewoehner B. , Single F. N. , Hvalby Ø. , Jensen V. , Meyer zum Alten Borgloh S. , Seeburg P. H. , Rawlins J. N. P. , Sprengel R. , Bannerman D. M.
Published: February 2007

Novel spatially restricted genetic manipulations can be used to assess contributions made by synaptic plasticity to learning and memory, not just selectively within the hippocampus, but even within specific hippocampal subfields. Here we generated genetically modified mice (NR1ΔDG mice) exhibiting complete loss of the NR1 subunit of the N‐methyl‐d‐aspartate receptor specifically in the granule cells of the dentate gyrus. There was no evidence of any reduction in NR1 subunit levels in any of the other hippocampal subfields, or elsewhere in the brain. NR1ΔDG mice displayed severely impaired long‐term potentiation (LTP) in both medial and lateral perforant path inputs to the dentate gyrus, whereas LTP was unchanged in CA3‐to‐CA1 cell synapses in hippocampal slices. Behavioural assessment of NR1ΔDG mice revealed a spatial working memory impairment on a three‐from‐six radial arm maze task despite normal hippocampus‐dependent spatial reference memory acquisition and performance of the same task. This behavioural phenotype resembles that of NR1ΔCA3 mice but differs from that of NR1ΔCA1 mice which do show a spatial reference memory deficit, consistent with the idea of subfield‐specific contributions to hippocampal information processing. Furthermore, this pattern of selective functional loss and sparing is the same as previously observed with the global GluR‐A l‐α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazelopropionate receptor subunit knockout, a mutation which blocks the expression of hippocampal LTP. The present results show that dissociations between spatial working memory and spatial reference memory can be induced by disrupting synaptic plasticity specifically and exclusively within the dentate gyrus subfield of the hippocampal formation.
Doublecortin‐like, a microtubule‐associated protein expressed in radial glia, is crucial for neuronal precursor division and radial process stability
Authors: Vreugdenhil Erno , Kolk Sharon M. , Boekhoorn Karin , Fitzsimons Carlos P. , Schaaf Marcel , Schouten Theo , Sarabdjitsingh Angela , Sibug Rosana , Lucassen Paul J.
Published: February 2007

During corticogenesis, progenitors divide within the ventricular zone where they rely on radial process extensions, formed by radial glial cell (RG) scaffolds, along which they migrate to the proper layers of the cerebral cortex. Although the microtubule‐associated proteins doublecortin (DCX) and doublecortin‐like kinase (DCLK) are critically involved in dynamic rearrangement of the cytoskeletal machinery that allow migration, little is known about their role in early corticogenesis. Here we have functionally characterized a mouse splice‐variant of DCLK, doublecortin‐like (DCL), exhibiting 73% amino acid sequence identity with DCX over its entire length. Unlike DCX, DCL is expressed from embryonic day 8 onwards throughout the early neuroepithelium. It is localized in mitotic cells, RGs and radial processes. DCL knockdown using siRNA in vitro induces spindle collapse in dividing neuroblastoma cells, whereas overexpression results in elongated and asymmetrical mitotic spindles. In vivo knockdown of the DCLK gene by in utero electroporation significantly reduced cell numbers in the inner proliferative zones and dramatically disrupted most radial processes. Our data emphasize the unique role of the DCLK gene in mitotic spindle integrity during early neurogenesis. In addition, they indicate crucial involvement of DCLK in RG proliferation and their radial process stability, a finding that has thus far not been attributed to DCX or DCLK.
EphA5 and ephrin‐A2 expression during optic nerve regeneration: a ‘two‐edged sword’
Authors: Symonds A. C. E. , King C. E. , Bartlett C. A. , Sauvé Y. , Lund R. D. , Beazley L. D. , Dunlop S. A. , Rodger J.
Published: February 2007

During development, gradients of EphA receptors (nasallow–temporalhigh) and their ligands ephrin‐As (rostrallow–caudalhigh) are involved in establishing topography between retinal ganglion cells (RGCs) and the superior colliculus (SC). EphA5‐expressing RGC axons are repulsed by ephrin‐A2‐expressing SC neurones. In adult rats RGCs maintain graded EphA5 expression but ephrin‐A2 expression is down‐regulated in the SC to a weak gradient. At 1 month after optic nerve transection, EphA5 expression is reduced in the few remaining RGCs and is no longer graded; by contrast, SC ephrin‐A2 is up‐regulated to a rostrallow–caudalhigh gradient. Here we examined expression in adult rat 1 month after bridging the retina and SC with a peripheral nerve graft, a procedure that enhances RGC survival and permits RGC axon regeneration. Double labelling with cell markers revealed preservation of a nasallow–temporalhigh EphA5 gradient in RGCs and establishment of a rostrallow–caudalhigh ephrin‐A2 gradient within neurones of the SC. The results suggest a potential for guidance cues to restore the topography of RGC axons in the SC. However, high ephrin‐A2 levels were also found in astrocytes surrounding the peripheral nerve graft insertion site. The repulsive ephrin‐A2 environment offers at least a partial explanation for the observation that only a limited number of RGC axons can exit the graft to enter target central nervous system tissue.
Optimal sustained attention is linked to the spectral content of background EEG activity: greater ongoing tonic alpha (∼10 Hz) power supports successful phasic goal activation
Authors: Dockree Paul M. , Kelly Simon P. , Foxe John J. , Reilly Richard B. , Robertson Ian H.
Published: February 2007

Efficient executive control frequently requires the timely activation or re‐activation of a task‐goal to enable purposeful behaviour. Additionally, more generalized factors such as alertness or neurological health will influence the efficiency with which control can be implemented. Goal‐directed processes have been investigated by examining event‐related potentials (ERPs), but much less is known about the involvement of background or ‘tonic’ processes reflected in the ongoing electroencephalogram (EEG), and how these affect the phasic processes expressed in the broad‐band ERP. Here, we investigate the relationship between a key attention‐sensitive tonic process – the alpha rhythm – and relevant phasic processes observed during a sustained attention paradigm in neurologically healthy subjects. We report that subjects with relatively higher tonic alpha power (∼10 Hz) show a larger‐amplitude late positive ERP component that is thought to index goal activation and has been found to predict good sustained attention performance as defined by correct response patterns. Source localization results suggest that the neural generators responsible for oscillatory alpha activity, which are found primarily in the parietal and occipital lobes, are distinct from those giving rise to the late positive component. The results are discussed in terms of increased alpha synchrony facilitating goal‐directed behaviour.
Contribution of NMDA receptor NR2B subunit to synaptic plasticity during associative learning in behaving rats
Authors: Valenzuela‐Harrington Mauricio , Gruart Agnès , Delgado‐García José M.
Published: February 2007

The difference in the amounts of NR2 subunits contained in NMDA receptors of the hippocampus has been related to their different involvement in activity‐dependent synaptic plasticity. Here, we show that Ro 25‐6981, a high‐affinity and selective blocker of NMDA receptors containing NR2B subunits, is able to block the acquisition of a trace conditioning paradigm in adult rats, a task that requires the active participation of hippocampal circuits. Reconditioning with the same trace paradigm was also prevented by Ro 25‐6981. In addition, we show that the slope of monosynaptic field excitatory postsynaptic potentials evoked at the dentate gyrus by single pulses presented to the medial perforant pathway increases significantly across conditioning sessions and during reconditioning, in a linear relationship with the increase in the number of classically conditioned eyelid responses. Administration of Ro 25‐6981 prevented these learning‐related changes in synaptic strength at the perforant pathway–dentate granule cell synapse. The present results suggest the involvement of NR2B‐containing NMDA receptors in hippocampal functions related to both associative learning and activity‐dependent synaptic plasticity.
Evaluation of transcranial magnetic stimulation for investigating transmission in descending motor tracts in the rat
Authors: Nielsen J. B. , Perez M. A. , Oudega M. , Enriquez‐Denton M. , Aimonetti J.‐M.
Published: February 2007

In the rat, non‐invasive transcranial magnetic stimulation (TMS) has shown promise for evaluation of transmission through the spinal cord before and after repair strategies, but it is still unclear which pathways are activated by TMS. The aim of the present study was therefore to identify these pathways and to analyse the effect of TMS on spinal neurons. In 19 rats, TMS evoked responses bilaterally in forelimb (biceps brachii; BB) and hindlimb muscles (tibialis anterior). The latency and amplitude of these motor‐evoked responses (MEPs) were highly variable and depended strongly on the coil position and the stimulation intensity. The most frequently observed latencies for the BB MEPs could be divided into three groups: 3–6 ms, 8–12 ms and 14–18 ms. Lesions in the dorsal columns, which destroyed the corticospinal tract at C2 and C5, significantly depressed MEPs in the mid‐ and high‐latency ranges, but not those in the low‐latency range. Lesions in the dorsolateral funiculus, which interrupted the rubrospinal tract, had no effect on MEPs in any of the latency ranges. By contrast, bilateral lesion of the reticulospinal tract and other ventro‐laterally located descending pathways abolished all responses. Intracellular recordings from 54 cervical motoneurons in five rats revealed that TMS evoked excitatory postsynaptic potentials (EPSPs) at latencies that corresponded well with those of the BB MEPs. The short‐latency EPSPs had rise times of around 1 ms, suggesting that they were mediated by a monosynaptic pathway. EPSPs with longer latencies had considerably longer rise times, which indicated conduction through polysynaptic pathways. Selective electrical stimulation of the pyramidal tract in the brainstem was performed in seven rats, where intracellular recordings from 70 motoneurons revealed that the earliest EPSPs and MEPs evoked by TMS were not mediated by the corticospinal tract, but by other descending motor pathways. Together, these results showed that in the rat TMS activates several descending pathways that converge on common spinal interneurons and motoneurons. Our observations confirm that the corticospinal tract has weak (and indirect) projections to cervical spinal motoneurons.
Diversity of GABAA receptor synaptic currents on individual pyramidal cortical neurons
Authors: Ing Timothy , Poulter Michael O.
Published: February 2007

Miniature GABAA receptor‐mediated inhibitory postsynaptic currents (mIPSCs) in cortical pyramidal neurons have previously been categorized into two types: small amplitude mIPSCs with a mono‐exponential deactivation (mono‐mIPSCs) and relatively larger mIPSCs with bi‐exponential deactivation (bi‐mIPSCs). The aim of this study was to determine if the GABAA channels that underlie these mIPSCSs are molecularly distinct. We found, using non‐stationary noise analysis, that the difference in their amplitude could be not accounted for by their single channel conductance (both were 40 pS). Next, using α subunit selective GABAA receptor modulators, we examined the identity of the α subunits that may be expressed in the synapses that give rise to these mIPSCs. Zolpidem (100 and 500 nm, α1 selective) affected the deactivation of a subset of the mono‐mIPSCs, indicating that α1 subunits are not highly expressed in these synapses. However, zolpidem (100 nm) prolonged the deactivation of all bi‐mIPSCs, indicating a high abundance of α1 subunits in these synapses. SB‐205384 (α3 selective) had no effect on the mono‐mIPSCs but the bi‐mIPSCs were prolonged. Furosemide (α4 selective) reduced the amplitude of only the mono‐mIPSCs. L655,708 (α5 selective) reduced the amplitude of both populations and shortened the duration of the mono‐mIPSCs. Finally, we found that the neuroactive steroid pregesterone sulphate reduced the amplitude of both mIPSC types. These results provide pharmacological evidence that synapses on cortical pyramidal neurons are molecularly distinct. The purpose of these different types of synapses may be to provide different inhibitory timing patterns on these cells.
Inflammatory responses following Chlamydia pneumoniae infection of glial cells
Authors: Boelen E. , Steinbusch H. W. M. , Pronk I. , Grauls G. , Rennert P. , Bailly V. , Bruggeman C. A. , Stassen F. R. M.
Published: February 2007

Recently, infections have been implicated in the pathogenesis of Alzheimer's disease. Apart from the direct effects of pathogens, it can be hypothesized that inflammatory mechanisms, such as the production of pro‐inflammatory mediators by resident glia, may result in neurotoxicity. Here, we examined the inflammatory responses in murine microglial cell (MMC) and murine astrocyte cell (MAC) lines following infection with Chlamydia pneumoniae (Cpn), a pathogen that has recently been associated with Alzheimer's disease. Furthermore, we determined whether these inflammatory responses are sufficient to cause neuronal cell death in vitro. MMCs and MACs were infected with Cpn. Subsequently, various chemo‐ and cytokines were determined in the culture supernatant fluid of infected/control cells at different time points post‐infection. Significantly higher levels of monocyte chemoattractant protein 1, interleukin (IL)‐6, tumour necrosis factor (TNF)‐α and IL‐1β were found in supernatant fluids of infected MMCs compared with controls. In contrast, in the supernatant fluid of infected MACs, only monocyte chemoattractant protein 1 and IL‐6 displayed significantly higher levels compared with controls. Moreover, neurotoxicity was examined up to 72 h after transferring the conditioned supernatant fluid to a neuronal cell layer. No neuronal cell death was observed when supernatant fluids from infected/mock‐treated MACs were transferred. However, when neurones were exposed to conditioned supernatant fluid from infected MMCs, a significant increase in cell death was observed compared with mock. Furthermore, adding neutralizing antibodies against IL‐6 and TNF‐α to that conditioned supernatant fluid prevented neuronal cell death by ∼50%. In conclusion, these data suggest that Cpn infection results in a pro‐inflammatory milieu, particularly by activating MMCs, that ultimately results in neurodegeneration with prominent roles for both IL‐6 and TNF‐α.