bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional topography of the human nonREM sleep electroencephalogram
Authors: Finelli Luca A. , Borbély Alexander A. , Achermann Peter 
Published: March 2003

AbstractThe sleep EEG of healthy young men was recorded during baseline and recovery sleep after 40 h of waking. To analyse the EEG topography, power spectra were computed from 27 derivations. Mean power maps of the nonREM sleep EEG were calculated for 1‐Hz bins between 1.0 and 24.75 Hz. Cluster analysis revealed a topographic segregation into distinct frequency bands which were similar for baseline and recovery sleep, and corresponded closely to the traditional frequency bands. Hallmarks of the power maps were the frontal predominance in the delta and alpha band, the occipital predominance in the theta band, and the sharply delineated vertex maximum in the sigma band. The effect of sleep deprivation on EEG topography was determined by calculating the recovery/baseline ratio of the power spectra. Prolonged waking induced an increase in power in the low‐frequency range (1–10.75 Hz) which was largest over the frontal region, and a decrease in power in the sigma band (13–15.75 Hz) which was most pronounced over the vertex. The topographic pattern of the recovery/baseline power ratio was similar to the power ratio between the first and second half of the baseline night. These results indicate that changes in sleep propensity are reflected by specific regional differences in EEG power. The predominant increase of low‐frequency power in frontal areas may be due to a high ‘recovery need’ of the frontal heteromodal association areas of the cortex.
Long‐lasting hippocampal potentiation and contextual memory consolidation
Authors: Sacchetti Benedetto , Lorenzini Carlo Ambrogi , Baldi Elisabetta , Bucherelli Corrado , Roberto Marisa , Tassoni Giovanna , Brunelli Marcello 
Published: March 2003

AbstractIn order to ascertain whether there are hippocampal electrophysiological modifications specifically related to memory, exploratory activity and emotional stress, extracellular electrical activity was recorded in hippocampal slices prepared from the brains of male adult rats. Several groups of animals were employed: (i) rats which had freely explored the experimental apparatus (8 min exposure); (ii) rats which had been subjected, in the same apparatus, to a fear conditioning paradigm training entailing the administration of aversive electrical footshocks (8 min exposure); (iii) rats to which the same number of aversive shocks had been administered in the same apparatus, but temporally compressed so as to make difficult the association between painful stimuli and the apparatus (30 s exposure); (iv) naïve rats never placed in the apparatus. Half of the rats from each treatment group were used for retrieval testing and the other half for hippocampal excitability testing. The conditioned freezing response was exhibited for no less than 4 weeks. Hippocampal excitability was measured by means of input–output curves (IOC) and paired‐pulse facilitation curves (PPF). Retrieval testing or brain slices preparation were performed at increasing delays after the training sessions: immediately afterwards or after 1, 7 or 28 days. Only the rats subjected to the fear conditioning training exhibited freezing when placed again in the apparatus (retrieval testing). It was found that IOCs, with respect to naïve rats, increased in the conditioned animals up to the 7‐day delay. In free exploration animals the IOCs increased only immediately after the training session. In all other rats no modification of the curves was observed. IOC increases do not appear to imply presynaptic transmitter release modifications, because they were not accompanied by PPF modifications. In conclusion, a clear‐cut correlation was found between the increase in excitability of the Schaffer collateral–CA1 dendrite synapses and freezing response consolidation.
Phospholipase A2 mediates ischemic injury in the hippocampus: a regional difference of neuronal vulnerability
Authors: Arai Ken , Ikegaya Yuji , Nakatani Yoshihito , Kudo Ichiro , Nishiyama Nobuyoshi , Matsuki Norio 
Published: March 2003

AbstractAlthough it is well known that the hippocampal CA1 subfield is highly vulnerable to ischemic injury, cellular mechanisms leading to this neuronal degeneration are not fully understood. Using organotypic cultures of rat hippocampal slices, we determined whether phospholipase A2 (PLA2) is activated in response to ischemic conditions (OGD; oxygen and glucose deprivation). The PLA2 activity in the pyramidal cell layer increased immediately following a 35‐min exposure to OGD, which was likely to be mediated by selective activation of cytosolic Ca2+‐dependent PLA2 subtype (cPLA2). This enhancement lasted for at least 24 h. Interestingly, no apparent increase was detected in the dentate gyrus. Twenty‐four hours after the OGD exposure, neuronal death was detected mainly in the CA1 region of hippocampal slices. To examine whether the PLA2 activation is causally or protectively involved in the ischemic injury, we investigated the effect of pharmacological blockade of PLA2 on the OGD‐induced neuronal death. The PLA2 inhibitor bromophenacyl bromide efficiently prevented the cell death in a concentration‐dependent manner. Similar results were obtained for the selective cPLA2 inhibitor AACOCF3. However, the Ca2+‐independent PLA2 inhibitor bromoenol lactone and the secretory PLA2 inhibitor LY311727 were virtually ineffective. These results suggest that cPLA2 plays a causative role in the neuronal death following OGD exposure. Thus, the present study may provide novel therapeutic targets for the development of neuroprotective agents.
Blockade of superoxide generation prevents high‐affinity immunoglobulin E receptor‐mediated release of allergic mediators by rat mast cell line and human basophils
Authors: Yoshimaru T. , Suzuki Y. , Matsui T. , Yamashita K. , Ochiai T. , Yamaki M. , Shimizu K. 
Published: March 2003

SummaryBackground Previous studies have shown that rat peritoneal mast cells and mast cell model rat basophilic leukaemia (RBL‐2H3) cells generate intracellular reactive oxygen species (ROS) in response to antigen challenge. However, the physiological significance of the burst of ROS is poorly understood.Objective The present study was undertaken to investigate the role of superoxide anion in mediator release in rat and human cell systems.Methods RBL‐2H3 cells were directly stimulated with anti‐rat FcεRI α‐subunit monoclonal antibody (mAb). For the analysis of human cell system, leucocytes were isolated by dextran sedimentation from healthy volunteers or from patients, and challenged either with anti‐human FcεRI mAb or with the relevant antigens. Superoxide generation was determined by chemiluminescence‐based methods. The releases of histamine and leukotrienes (LT)s were determined by enzyme‐linked immunosorben assay (ELISA).Results Cross‐linking of FcεRI on RBL‐2H3 cells or on human leucocytes from healthy donors by the anti‐FcεRI mAb resulted in a rapid generation of superoxide anion, as determined by chemiluminescence using superoxide‐specific probes. Similarly, leucocytes from patients generated superoxide anion in response to the challenge with the relevant allergen but not with the irrelevant allergen. Furthermore, diphenyleneiodonium (DPI), a well‐known inhibitor of flavoenzymes suppressed the superoxide generation and the release of histamine and LTC4 induced by the anti‐FcεRI mAb or by allergen in parallel.Conclusion These results indicate that both RBL‐2H3 cells and human basophils generate superoxide anion upon FcεRI cross‐linking either by antibody or by allergen challenge and that blockade of the generation prevents the release of allergic mediators. The findings strongly support the role of superoxide generation in the activation of mast cells and basophils under both physiological and pathological conditions. The findings suggest that drugs regulating the superoxide generation have potential therapeutic use for allergic disorders.
Effects of birch pollen and traffic particulate matter on Th2 cytokines, immunoglobulin E levels and bronchial hyper‐responsiveness in mice
Authors: Fernvik E. , Peltre G. , Sénéchal H. , Vargaftig B. B. 
Published: March 2003

SummaryBackground Health effects due to air pollution arizing from motor vehicles are a major public and political concern world‐wide. Epidemiological studies have shown that the manifestations of asthma are increased by air pollution in already affected individuals.Objective To investigate the potential role of air‐polluted tunnel dust (traffic particulate matter, TPM) or pure carbon core particles in the initiation and persistence of experimental allergic inflammation.Methods BP2 mice were immunized with birch pollen alone (group B) or pollen together with TPM (group A), or with birch pollen and Al(OH)3 (group C), or with birch pollen and carbon core particles (group D). Before methacholine challenge they were challenged intranasally and thereafter bronchial hyper‐reactivity (BHR) was evaluated in a whole‐body plethysmograph. Levels of Th2 cytokines, fibronectin and lactate dehydrogenase (LDH) were determined, and differential counts were performed in the bronchoalveolar lavage (BAL) fluid. Sera were collected for determination of antibody titres and cytokine levels.Results Specific IgE titres, BHR, the number of recruited eosinophils and levels of fibronectin and LDH in BAL were increased in mice immunized and challenged with a mixture of birch pollen and TPM. However, mice immunized with birch pollen alone and challenged intranasally with pollen or a mixture of pollen and TPM demonstrated the highest levels of IL‐4 and IL‐5.Conclusion This study highlights the importance of the exposure to a combination of particulate matters and pollen allergens, in the induction of allergic disease in the airways, and we have demonstrated that polluted tunnel dust has an effect on both the inflammatory and immunological components of experimental allergy. Immunization and challenge with carbon core particles together with birch pollen increased neither the BHR nor the specific IgE production significantly. Our results therefore strongly suggest that it is most likely to be the organic phase bound to the carbon core of the diesel exhaust particles that might have an important adjuvant effect in the induction of experimental allergy.
Cell migration and organization in the intestinal crypt using a lattice‐free model
Authors: Meineke F. A. , Potten C. S. , Loeffler M. 
Published: March 2003

Abstract.We present a novel class of spatial models of cell movement and arrangement applied to the two‐dimensional cellular organization of the intestinal crypt. The model differs from earlier approaches in using a dynamic movement on a lattice‐free cylindrical surface. Cell movement is a consequence of mitotic activity. Cells interact by viscoelastic forces. Voronoi tessellation permits simulations of individual cell boundaries. Simulations can be compared with experimental data obtained from cell scoring in sections. Simulation studies show that the model is consistent with the experimental results for the spatial distribution of labelling indices, mitotic indices and other observed phenomena using a fixed number of stem cells and a fixed number of transit cell divisions.
The use of emergency contraception in Australasian emergency departments
Authors: Millar J Robert , Leach Deborah S , Maclean Andrew V , Kovacs Gabor T 
Published: March 2003

AbstractObjective:To review the prescribing of emergency contraception by emergency departments in Australasia and compare it with other providers.Methods:A postal questionnaire was sent to the director of each of the 79 Australasian College for Emergency Medicine accredited emergency deparatments in Australasia inquiring about the availability and prescribing habits for emergency contraception within each department.Results:Of the 79 emergency departments, 69 (87.3%) responded to the questionnaire and were aware of the ‘emergency contraception regimen’. The majority of departments prescribed appropriately (56%) and only one department did not arrange adequate follow up. Anti‐emetics are always used by 45 departments (78.9%). Discussion of future contraceptive needs at the time of presentation was only undertaken by 25 departments (43.9%). Written clinical guidelines for emergency contraception were present in 28 departments (40.6%).Conclusions:Emergency departments are accessed by patients requesting contraception following unprotected intercourse or contraceptive failure. The prescribing of emergency contraception in Australasian emergency departments is comparable with other providers but substantial improvements could be made. Suggestions to assist this improvement include written clinical guidelines and patient information and purpose‐made medication packs.
Emergency department triage of indigenous and non‐indigenous patients in tropical Australia
Authors: Johnston‐Leek Malcolm , Sprivulis Peter , Stella Julian , Palmer Didier 
Published: March 2003

AbstractObjective:To examine the relationship between ethnicity and triage at a tertiary hospital emergency department.Methods:Electronic Emergency Department Information System data analysis was used to examine the relationship between ethnicity and triage allocation and process times between 1 April 1999 and 29 June 1999. Outcome measures were waiting times by triage category and admission rate by triage category.Results:There were 9614 attendances: 1949 indigenous (20.3%), 7328 non‐indigenous (76.2%) and 337 (3.5%) had no ethnicity recorded. Indigenous patients were more often female (1033; 53%, CI 51–55%) than non‐indigenous patients (3078; 42.0%, CI 41–43%,P < 0.001). Indigenous patients presented more often with illness (70% CI 68–72%) rather than injury (30%, CI 28–32%), compared with the non‐indigenous patients, illness (64%, CI 63–65%), injury (36%, CI 35–37%,P < 0.001). Indigenous patients were more likely to be triaged to national triage scale categories 1, 2 or 3 (36%, CI 34–38%) than non‐indigenous patients (32%, CI 31–33%,P = 0.011). Admission rates for indigenous patients were higher than non‐indigenous patients across all urgency categories and were within national triage scale guidelines. Non‐indigenous admission rates were well below national triage scale guidelines for all urgency categories. The overall admission rate for indigenous patients was double (33%, CI 31–35%) that for non‐indigenous patients (16%, CI 15–17%,P < 0.001). There was no significant difference between indigenous and non‐indigenous waiting times.Conclusion:Indigenous patients are more likely to present with illness rather than injury and are more likely to require admission than non‐indigenous patients. Indigenous patients are triaged in accordance with Australasian triage guidelines. Many non‐indigenous patients should be triaged to lower urgency categories to allow resource allocation towards higher acuity indigenous and non‐indigenous patients.
Comparative sequence analysis of four myosin heavy chain isoforms expressed in porcine skeletal muscles: Sequencing and characterization of the porcine myosin heavy chain slow isoform
Authors: CHIKUNI Koichi , MUROYA Susumu , TANABE Ryo‐ichi , NAKAJIMA Ikuyo 
Published: March 2003

ABSTRACTA nucleotide sequence including the full coding region for the myosin heavy chain (MyHC) slow isoform was determined from the longissimus skeletal muscle. The deduced amino acid sequence was 1935 residues, which was the same length as the human and rat MyHC‐slow isoforms. The porcine MyHC‐slow isoform showed 97.6% and 97.4% amino acid identities to the human and rat isoforms on their entire regions, respectively. The functional regions were also highly conserved among mammalian MyHC‐slow isoforms. Amino acid substitutions between the porcine MyHC‐slow and MyHC‐fast isoforms were concentrated on the functional regions. Loop 1, the controlling region of nucleotide binding and release, was conserved among the fast isoforms, but not between the slow and fast isoforms. Loop 2, a part of the actin binding region, was not conserved among any of the isoform types, and the most substitutions in this region were found in the slow isoform. The myosin essential light chain binding region was conserved among the fast isoforms, except for some substitutions in the 2b isoform, but was clearly different in the slow isoform. The myosin regulatory light chain binding region was conserved among the fast isoforms, but not between the slow and fast isoforms. These results indicate that the functional difference between the porcine MyHC‐slow and ‐fast isoforms are controlled by the sequence diversity at the four functional regions compared.
Partitioning of genetic values associated with identified genotype and residual genotype
Authors: LIN Ching Y. 
Published: March 2003

ABSTRACTA simplified partition procedure was developed to partition the genetic value associated with the identified genotype (a combined genotype of all quantitative trait loci (QTL) identified) and residual genotype. The simplified partition procedure does not require the construction of mixed model equations for both identified and residual genotypes, and therefore drastically reduces the computing requirements as compared with the direct partition procedure. Both the simplified and the direct partition procedures were shown to be equivalent theoretically and experimentally. The simplified partition procedure also applies to the partitioning of other random effects such as the partition of sire effect into two components (constant and interaction sire effects) without actually solving the mixed model equations of the partitioned sire model. The relative contribution of the identified loci and the residual genotypes to the genetic value of a trait depends on their correlation (ρqr) and the ratio of their genetic variances (σ2q/σ2r). Identifying more QTL or increasing QTL variance would add to the contribution of identified QTL to the total genetic value of a quantitative trait. However, the additional contribution of identifying each extra QTL increases at a decreasing rate when the correlation between identified and residual genotypes is positive, but at an increasing rate when the correlation is negative. An effective QTL‐assisted selection program should consider both direct and associated effects of the identified loci.
Age‐related changes in contractions of chicken aorta and ischiadic artery
Authors: ABE Asaki , OHTSUKI Kazumasa , SUZUKI Yoshiki , TAKAHASHI Takiko , KONDO Yasuhiro 
Published: March 2003

ABSTRACTThe characteristics of the contraction of vascular smooth muscle were examined in thoracic aorta and ischiadic artery of chickens aged 3, 6, 10 and 18 weeks. High K+ solution induced a sustained contraction in smooth muscle preparations of aorta and ischiadic artery in vitro. The contraction of the ischiadic artery became greater with age, whereas the contraction of the aortic preparation did not. In the ischiadic artery, the magnitude of the contraction divided by the weight of the muscle preparation was constant at all ages studied. However, those in the aortic preparation decreased with age. These results suggest that the changes in the contractile responses of vascular smooth muscle owing to the age of chickens vary widely according to the preparations of blood vessels, and that the functional smooth muscle cells in the thoracic aorta of chicken do not increase with age.
Increase in expression of growth hormone secretagogues receptor on differentiation of ovine preadipocytes
Authors: ROH Sang‐gun , CHOI Ki‐choon , SHRESTHA Yogendra B. , YOON Chang , Woo Jung‐Hee , SASAKI Shin‐ichi 
Published: March 2003

ABSTRACTThe mechanism by which ghrelin (endogenous growth hormone secretagogues; GHS) is involved with the differentiation of preadipocytes to adipocytes has remained largely unknown. To investigate this issue, we monitored the level of GHS receptor (GHS‐R) mRNA during the differentiation of primary cultured ovine preadipocytes. The preadipocytes, which were obtained from ovine subcutaneous adipose tissues, were proliferated to confluence and then differentiated to adipocytes in differentiation medium for 10 days. The confluent preadipocytes and differentiated adipocytes at Days 3, 7 and 10 were harvested for total RNA extraction and semiquantitative reverse transcription–polymerase chain reaction analysis of GHS‐R mRNA. The level of GHS‐R mRNA was significantly increased during the differentiation process, whereas it was undetectable in the confluent preadipocytes. Our results demonstrate that GHS‐R exists in adipocytes and ghrelin may be a new regulatory factor in the process of differentiation of ovine preadipocytes.
Effects of dietary energy levels on plasma leptin in sheep
Authors: TOKUDA Tomomi , DELAVAUD Carole , CHILLIARD Yves 
Published: March 2003

AbstractThis experiment investigates the changes in the plasma leptin levels of sheep fed a diet of three energy levels (low, moderate and high). Four mature wethers were used for this experiment. For the first 4 weeks, the sheep were fed diets to provide 1.2 times the maintenance metabolizable energy requirements, low energy levels (LE). During the second 4 weeks, the sheep were fed diets to provide 1.5 times the maintenance metabolizable energy requirements, moderate energy levels (ME). During third 4‐week period, the sheep were fed a diet to provide 1.8 times the maintenance metabolizable energy requirements, high energy levels (HE). Body weight was determined every week. Blood samples were collected prior to the morning meal at 3 days intervals throughout the experiment, and plasma leptin, insulin and nonesterified fatty acid (NEFA) concentrations were assayed. Body weight decreased in week 1 after the start of the experiment, it continued to decrease during the LE feeding, but it gradually increased until the end of HE period. Similarly, plasma leptin concentration decreased during LE feeding, but increased during the HE feeding. Additionally, positive correlation was obtained between leptin and insulin or glucose concentrations, whereas no clear relationship with circulating NEFA was observed. In conclusion, it was suggested that plasma leptin concentrations were affected by the metabolizable energy in feed.
Immunohistochemical study of matrix metalloproteinase‐3 (MMP‐3) at the articular cartilage in osteochondrotic pigs
Authors: OHATA Hiroyoshi , ZUSHIDA Kenji , SUGIYAMA Toshie , KUSUHARA Seiji 
Published: March 2003

ABSTRACTIn order to understand the mechanism of osteochondrosis in the pig, articular cartilage was taken from the distal femoral condyles of Duroc pigs exhibiting leg weakness and then examined immunohistochemically for the localization of matrix metalloproteinases‐3 (MMP‐3), one of the enzymes involved in the resolution of cartilage matrix. The articular cartilage had the typical characteristics of osteochondrotic lesions, such as abnormal calcification, clefts of cartilage, disappearance of proteoglycan, and necrotic chondrocytes. The immunoreaction of MMP‐3 was observed in chondrocytes at the boundary between normal cartilage and proteoglycan‐deficient area. Moreover, chondrocytes expressing MMP‐3 showed normal morphology, but the surrounding cartilage matrix did not stain with toluidine blue, which indicated a lack of glycosaminoglycans. These results suggest that MMP‐3 is highly involved in the appearance and expansion of osteochondrotic lesions.