bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular characterization of MbADGF, a novel member of the adenosine deaminase‐related growth factor in the cabbage armyworm, Mamestra brassicae: the functional roles in the midgut cell proliferation
Authors: Zhang J. , Takeda M. 
Published: April 2007

AbstractTo clarify the functional mechanism of the adenosine deaminase‐related growth factor (ADGF) particularly in the regulation of insect development, the cDNA encoding a homologue of ADGF proteins was cloned from the cabbage armyworm, Mamestra brassicae, named MbADGF. The purified MbADGF recombinant protein stimulated cell proliferation in a dose‐dependent manner of SES‐MaBr‐4 and NIAS‐MaBr‐93 cell lines that were derived from fat bodies and haemocytes of M. brassicae. The adenosine deaminase activity of MbADGF was detected using adenosine and 2′‐deoxyadenosine as substrates. Northern analysis demonstrated that during the larval development the level of MbADGF in the midgut increased. In situ hybridization showed that MbADGF mRNA was expressed in midgut goblet cells and in the apical cytoplasm of columnar cells, which suggests that MbADGF protein may execute its adenosine deaminase activity at the apical cytoplasm of columnar cells to convert adenosine into inosine.
Fluorescence lifetime imaging microscopy ofChlamydomonas reinhardtii: non‐photochemical quenching mutants and the effect of photosynthetic inhibitors on the slow chlorophyll fluorescence transient
Authors: HOLUB O. , SEUFFERHELD M. J. , GOHLKE C. , GOVINDJEE  , HEISS G. J. , CLEGG R. M. 
Published: April 2007

SummaryFluorescence lifetime‐resolved images of chlorophyll fluorescence were acquired at the maximum P‐level and during the slower transient (up to 250 s, including P‐S‐M‐T) in the green photosynthetic algaChlamydomonas reinhardtii. At the P‐level, wild type and the violaxanthin‐accumulating mutant npq1 show similar fluorescence intensity and fluorescence lifetime‐resolved images. The zeaxanthin‐accumulating mutant npq2 displays reduced fluorescence intensity at the P‐level (about 25–35% less) and corresponding lifetime‐resolved frequency domain phase and modulation values compared to wild type/npq1. A two‐component analysis of possible lifetime compositions shows that the reduction of the fluorescence intensity can be interpreted as an increase in the fraction of a short lifetime component. This supports the important photoprotection function of zeaxanthin in photosynthetic samples, and is consistent with the notion of a ‘dimmer switch’. Similar, but quantitatively different, behaviour was observed in the intensity and fluorescence lifetime‐resolved imaging measurements for cells that were treated with the electron transport inhibitor 3‐(3,4‐dichlorophenyl)‐1,1‐dimethyl urea, the efficient PSI electron acceptor methyl viologen and the protonophore nigericin and. Lower fluorescence intensities and lifetimes were observed for all npq2 mutant samples at the P‐level and during the slow fluorescence transient, compared to wild type and the npq1 mutant.The fluorescence lifetime‐resolved measurements during the slow fluorescence changes after the P level up to 250 s for the wild type and the two mutants, in the presence and absence of the above inhibitors, were analyzed with a graphical procedure (polar plots) to determine lifetime compositions. At higher illumination intensity, wild type and npq1 cells show a rise in fluorescence intensity and corresponding rise in the species concentration of the slow lifetime component after the initial decrease following the P level. This reversal is absent in the npq2 mutant, and for all samples in the presence of the inhibitors. Lifetime heterogeneities were observed in experiments averaged over multiple cells as well as within single cells, and these were followed over time. Cells in the resting state (induced by several hours of darkness), instead of the normal swimming state, show shortened lifetimes. The above results are discussed in terms of a superposition of effects on electron transfer and protonation rates, on the so‐called ‘State Transitions’, and on non‐photochemical quenching. Our data indicate two major populations of chlorophyll a molecules, defined by two ‘lifetime pools’ centred on slower and faster fluorescence lifetimes.
Precision of light intensity measurement in biological optical microscopy
Authors: BERNAS TYTUS , BARNES DAVID , ASEM ELIKPLIMI K. , ROBINSON J. PAUL , RAJWA BARTEK 
Published: April 2007

SummaryStandardization and calibration of optical microscopy systems have become an important issue owing to the increasing role of biological imaging in high‐content screening technology. The proper interpretation of data from high‐content screening imaging experiments requires detailed information about the capabilities of the systems, including their available dynamic range, sensitivity and noise. Currently available techniques for calibration and standardization of digital microscopes commonly used in cell biology laboratories provide an estimation of stability and measurement precision (noise) of an imaging system at a single level of signal intensity. In addition, only the total noise level, not its characteristics (spectrum), is measured. We propose a novel technique for estimation of temporal variability of signal and noise in microscopic imaging. The method requires registration of a time series of images of any stationary biological specimen. The subsequent analysis involves a multi‐step process, which separates monotonic, periodic and random components of every pixel intensity change in time. The technique allows simultaneous determination of dark, photonic and multiplicative components of noise present in biological measurements. Consequently, a respective confidence interval (noise level) is obtained for each level of signal. The technique is validated using test sets of biological images with known signal and noise characteristics. The method is also applied to assess uncertainty of measurement obtained with two CCD cameras in a wide‐field microscope.
Challenges faced by general practitioners and allied mental health services in providing mental health services in rural Queensland
Authors: Bambling Matthew , Kavanagh David , Lewis Gisela , King Robert , King David , Sturk Heidi , Turpin Merrill , Gallois Cindy , Bartlett Helen 
Published: April 2007

AbstractObjective:  To examine the views of rural practitioners concerning issues and challenges in mental health service delivery and possible solutions. Design:  A qualitative study using individual semi‐structured interviews. Setting:  Eight general practices from eight rural Queensland towns, three rural mental health services and two non‐government organisations, with interviews being conducted before recent changes in government‐subsidised access to allied health practitioners. Participants:  A sample of 37 GPs, 19 Queensland Health mental health staff and 18 participants from community organisations. Main outcome measures:  Analysis of qualitative themes from questions about the key mental health issues facing the town, how they might be addressed and what challenges would be faced in addressing them. Results:  There was substantial consensus that there are significant problems with inter‐service communication and liaison, and that improved collaboration and shared care will form a critical part of any effective solution. Differences between groups reflected differing organisational contexts and priorities, and limitations to the understanding each had of the challenges that other groups were facing. Conclusions:  Improvements to mental health staffing and to access to allied health might increase the ability of GPs to meet the needs of less complex patients, but specific strategies to promote better integrated services are required to address the needs of rural and regional patients with complex mental health problems. The current study provides a baseline against which effects of recent initiatives to improve mental health care can be assessed.
SPONTANEOUS OSCILLATORY CONTRACTIONS IN AORTAS OF RATS WITH ARTERIAL PRESSURE LABILITY CAUSED BY SINOAORTIC DENERVATION
Authors: Rocha Matheus L , Bendhack Lusiane M 
Published: April 2007

SUMMARY

The spontaneous variation of blood pressure is defined as arterial pressure lability. Sinoaortic denervation (SAD) is characterized by arterial pressure lability without sustained hypertension.
The phenomenon of spontaneous oscillatory contractions (SOCs) occurs more frequently in the vascular beds of hypertensive animals. In large arteries, such as the aorta, SOCs occur only occasionally or they can be initiated by application of chemical stimuli.
In the present study, we investigated whether the arterial pressure lability evoked by SAD could be related to the emergence of SOCs in the aorta of rats submitted to SAD compared with sham‐operated rats (SO). Three days after surgery (SAD or SO), aortic rings were placed in an organ chamber and the incidence (percentage of rats presenting SOCs), frequency (number of SOCs in 10 min) and amplitude (mN) of SOCs were measured. The participation of external Ca2+ and K+ channels in the maintenance of SOCs was also verified.
The incidence and frequency of SOCs were higher in endothelium‐denuded aortas from SAD rats (82% and 38 ± 4 SOCs/10 min, respectively) than in aortas from SO rats (40% and 14 ± 2 SOCs/10 min, respectively). In aortas from SAD rats, verapamil (0.2 µmol/L), pinacidil (0.3 µmol/L) and tetraethylammonium (TEA; 5 mmol/L) totally inhibited SOCs, whereas increasing the CaCl2 concentration to 2.0 and 2.5 mmol/L increased the frequency of SOCs. Interestingly, increasing the concentration of CaCl2 to 3.5 mmol/L inhibited these contractions in aortas from SAD rats.
These results show that although SAD rats did not become hypertensive, their aortas were capable of initiating SOCs without the application of any chemical stimuli. The SOCs seem to be dependent on Ca2+ influx sensitive to verapamil and also involve K+ channels sensitive to pinacidil and TEA.
MAXIMAL LACTATE STEADY STATE IN RUNNING MICE: EFFECT OF EXERCISE TRAINING
Authors: Ferreira Julio CB , Rolim Natale PL , Bartholomeu Jan B , Gobatto Claudio A , Kokubun Eduardo , Brum Patricia C 
Published: April 2007

SUMMARY

Maximal lactate steady state (MLSS) corresponds to the highest blood lactate concentration (MLSSc) and workload (MLSSw) that can be maintained over time without continual blood lactate accumulation and is considered an important marker of endurance exercise capacity. The present study was undertaken to determine MLSSw and MLSSc in running mice. In addition, we provide an exercise training protocol for mice based on MLSSw.
Maximal lactate steady state was determined by blood sampling during multiple sessions of constant‐load exercise varying from 9 to 21 m/min in adult male C57BL/6J mice. The constant‐load test lasted at least 21 min. The blood lactate concentration was analysed at rest and then at 7 min intervals during exercise.
The MLSSw was found to be 15.1 ± 0.7 m/min and corresponded to 60 ± 2% of maximal speed achieved during the incremental exercise testing. Intra‐ and interobserver variability of MLSSc showed reproducible findings. Exercise training was performed at MLSSw over a period of 8 weeks for 1 h/day and 5 days/week. Exercise training led to resting bradycardia (21%) and increased running performance (28%). Of interest, the MLSSw of trained mice was significantly higher than that in sedentary littermates (19.0 ± 0.5 vs 14.2 ± 0.5 m/min; P = 0.05), whereas MLSSc remained unchanged (3.0 mmol/L).
Altogether, we provide a valid and reliable protocol to improve endurance exercise capacity in mice performed at highest workload with predominant aerobic metabolism based on MLSS assessment.
INTERPLAY OF REACTIVE OXYGEN SPECIES AND NITRIC OXIDE IN THE PATHOGENESIS OF EXPERIMENTAL LEAD‐INDUCED HYPERTENSION
Authors: Vaziri ND , Khan M 
Published: April 2007

SUMMARYLead is a common environmental and industrial toxin that can cause a variety of acute and chronic illnesses. For example, chronic exposure to low levels of lead has been shown to raise arterial pressure and promote renal and cardiovascular complications.Several mechanisms have been identified by which chronic lead exposure can cause hypertension and cardiovascular disease. In recent years, increasing evidence has emerged pointing to the role of oxidative stress as a major mediator of lead‐induced hypertension.The present article provides an overview of the published studies on this subject.
TIME‐DEPENDENT COURSE OF HYPERBARIC OXYGEN‐INDUCED OXIDATIVE EFFECTS IN RAT LUNG AND ERYTHROCYTES‡
Authors: Ay Hakan , Topal Turgut , Uysal Bülent , Özler Mehmet , Öter Sükrü , Korkmaz Ahmet , Dündar Kadir 
Published: April 2007

SUMMARY

The oxygen toxicity of hyperbaric oxygen (HBO) treatment has long been of interest. There is an extensive amount of information regarding the role oxidative stress plays after HBO exposure in different tissues, but the question of the persistence of this oxidative effect has not been thoroughly elucidated.
The present study was performed to elucidate the persistence of the oxidative effects of HBO on rat lungs and erythrocytes after they had been subjected to 100% oxygen exposure.
Rats were divided into five groups. All animals, except those in the control group, were subjected to 100% oxygen for 2 h at 3 ATA (≡ 300 kPa). Rats were killed at 30, 60, 90 or 120 min after exposure and thiobarbituric acid‐reactive substances (TBARS) levels and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were determined.
Thiobarbituric acid‐reactive substances levels and SOD and GPx levels were found to be significantly increased in lung tissue up to 60 min after exposure. Superoxide dismutase activity persisted at significantly high values for 90 min after exposure in erythrocytes and the lung. The TBARS levels in erythrocytes were also significantly higher for 60 min, whereas increased GPx activity was observed to persist for only 30 min.
The oxidative effect of HBO exposure declines to physiological levels within 90 min at most for erythrocytes and in lung tissue in rats. Further studies should focus on the molecular mechanisms that can be activated during this time interval.
PROTECTIVE EFFECTS OF ICARIIN AGAINST LEARNING AND MEMORY DEFICITS INDUCED BY ALUMINIUM IN RATS
Authors: Luo Yong , Nie Jing , Gong Qi‐Hai , Lu Yuan‐Fu , Wu Qin , Shi Jing‐Shan 
Published: April 2007

SUMMARY

The present study examined the protective effects of icariin against the learning and memory deficits in aluminium‐treated rats and its potential mechanisms of action.
Qualified rats were treated with 1600 p.p.m. AlCl3 in drinking water for 8 months and the ability of spatial learning and memory was tested by the Morris water maze. In the place navigation test, aluminium administration significantly increased the mean escape latency and searching distance. In space probing test, aluminium markedly decreased the searching time and searching distance in the quadrant where the platform was originally located. All tests indicated deficits in rat spatial learning and memory induced by aluminium. Icariin treatment (60 and 120 mg/kg, by gavage for 3 months) dose‐dependently protected against the development of aluminium‐induced spatial learning and memory deficits.
To examine the mechanisms responsible for the protection afforded by icariin, the superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in the hippocampus were assayed biochemically and the level of Aβ1−40 in the hippocampus was determined immunohistochemically. Icariin treatment significantly increased SOD activity and decreased MDA and Aβ1−40 content in the hippocampus of aluminium‐intoxicated rats.
In conclusion, the present study demonstrates that icariin is effective in improving the spatial learning and memory of aluminium‐intoxicated rats. The mechanisms responsible appear to be due, at least in part, to an increased anti‐oxidant capacity and decreased lipid peroxidation and Aβ1−40 levels in the rat hippocampus.
CEREBRAL UPTAKE OF DRUGS IN HUMANS
Authors: Upton Richard N 
Published: April 2007

SUMMARYDrugs that target the central nervous system (CNS) are under‐represented in the pharmacopoeia because of the difficulties of overcoming passive and active defences of the blood–brain barrier (BBB). Methods have been developed in drug discovery to make decisions about whether a compound crosses the BBB. Less is known about how the rate and extent of CNS penetration of a drug affects its clinical behaviour, largely because of past difficulties in measuring the cerebral uptake of drugs in humans. Three methods for doing so are reviewed.Microdialysis is sometimes used as a clinical tool for monitoring the brain in neurointensive care and opportunistic pharmacological studies are possible. The method is relatively cheap and simple, measures free drug concentrations and is better suited to characterizing slowly changing brain drug concentrations.Measuring cerebral drug uptake using positron emission tomography imaging requires the use of short‐lived isotopes (labelled drug or labelled receptor ligand). Data with high spatial and temporal resolution can be collected, but the method requires expensive infrastructure.Jugular bulb catheters collect pure brain venous blood and are sometimes placed for neuromonitoring. Cerebral drug uptake is inferred from the arterial to cerebral venous concentration difference. The method is relatively cheap and simple and allows global brain concentrations to be estimated. It is better suited to characterizing rapidly changing brain concentrations and effects.The cerebral kinetics of a cerebro‐active drug can make substantial contributions to its clinical behaviour. For example, loperamide is a peripherally acting opioid that has little CNS effect due to the active efflux transport of loperamide from the brain back into the blood by transporters including P‐glycoprotein. The opioids alfentanil and fentanyl differ in their duration of action largely because of differences in their cerebral distribution volume rather than differences in systemic kinetics. The onset of anaesthesia of the intravenous anaesthetic propofol is governed almost completely by the kinetics of the first‐pass passage of the drug through the brain and is more affected by changes in cerebral blood flow than hepatic clearance.Continuing to exploit and develop these methods may provide new avenues to enhance the safety and efficacy of cerebro‐active drugs in clinical practice.
Using domain‐general principles to explain children's causal reasoning abilities
Authors: McClelland James L. , Thompson Richard M. 
Published: April 2007

AbstractA connectionist model of causal attribution is presented, emphasizing the use of domain‐general principles of processing and learning previously employed in models of semantic cognition. The model categorizes objects dependent upon their observed ‘causal properties’ and is capable of making several types of inferences that 4‐year‐old children have been shown to be capable of. The model gives rise to approximate conformity to normative models of causal inference and gives approximate estimates of the probability that an object presented in an ambiguous situation actually possesses a particular causal power, based on background knowledge and recent observations. It accounts for data from three sets of experimental studies of the causal inferencing abilities of young children. The model provides a base for further efforts to delineate the intuitive mechanisms of causal inference employed by children and adults, without appealing to inherent principles or mechanisms specialized for causal as opposed to other forms of reasoning.
On the relation between the acquisition of singular–plural morpho‐syntax and the conceptual distinction between one and more than one
Authors: Barner David , Thalwitz Dora , Wood Justin , Yang Shu‐Ju , Carey Susan 
Published: April 2007

AbstractWe investigated the relationship between the acquisition of singular–plural morpho‐syntax and children's representation of the distinction between singular and plural sets.Experiment 1tested 18‐month‐olds using the manual‐search paradigm and found that, like 14‐month‐olds (Feigenson & Carey, 2005), they distinguished three objects from one but not four objects from one. Thus, they failed to represent four objects as ‘plural’ or ‘more than one’.Experiment 2found that children continued to fail at the 1 vs. 4 manual‐search task at 20 months of age, even when told, via explicit morpho‐syntactic singular–plural cues, that one or many balls are being hidden. However, 22‐ and 24‐month‐olds succeeded both with and without verbal cues. Parental report data indicated that most 22‐ and 24‐month‐olds, but few 20‐month‐olds, had begun producing plural nouns in their speech. Also, the success among the older children was due to those children who had reportedly begun producing plural nouns. We discuss a possible role for language acquisition in children's deployment of set‐based quantification and the distinction between singular and plural sets.
Perception of object shape and texture in human newborns: evidence from cross‐modal transfer tasks
Authors: Sann Coralie , Streri Arlette 
Published: April 2007

Abstract The present research investigates newborn infants’ perceptions of the shape and texture of objects through studies of the bi‐directionality of cross‐modal transfer between vision and touch. Using an intersensory procedure, four experiments were performed in newborns to study their ability to transfer shape and texture information from vision to touch and from touch to vision. The results showed that cross‐modal transfer of shape is not bi‐directional at birth. Newborns visually recognized a shape previously held but they failed to tactually recognize a shape previously seen. In contrast, a bi‐directional cross‐modal transfer of texture was observed. Taken together, the results suggest that newborn infants, like older children and adults, gather information differently in the visual and tactile modes, for different object properties. The findings provide evidence for continuity in the development of mechanisms for perceiving object properties.
Gravity bias in young and adult chimpanzees (Pan troglodytes): tests with a modified opaque‐tubes task
Authors: Tomonaga Masaki , Imura Tomoko , Mizuno Yuu , Tanaka Masayuki 
Published: April 2007

AbstractYoung human children at around 2 years of age fail to predict the correct location of an object when it is dropped from the top of an S‐shape opaque tube. They search in the location just below the releasing point (Hood, 1995). This type of error, called a ‘gravity bias’, has recently been reported in dogs and monkeys. In the present study, we investigated whether young and adult chimpanzees also show such a gravity bias in a modified version of the original opaque‐tube task. The original task by Hood and colleagues required the subject to search in a location after the object had fallen, while in the task reported here, subjects were required to predict the location before the object was dropped. Thus the present procedure does not involve explicit invisible displacement operations, one of the important components of the original procedure. InExperiment 1both young (1.5–2.5‐year‐old) and adult chimpanzees predicted the location of falling food items below the releasing point even when crossed tubes were used. These gravity errors remained after the extensive experience of using the tubes themselves.Experiment 2further tested adult and 4‐year‐old chimpanzees under the set‐up in which the straight and crossed tubes were simultaneously presented. The results were the same as those in the previous test, suggesting that developmental changes and learning effect do not affect the gravity bias in chimpanzees.