bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of task context on reaching performance in children with spastic hemiparesis
Authors: Volman M (Chiel) JM , Wijnroks A (Lex) , Vermeer Adri 
Published: January 2003

Objective: To investigate the effect of task context on the quality of reaching movements in children with spastic hemiparesis. Design: Randomized controlled experimental trial. Setting: Institute for the Study of Education and Human Development (ISED). Subjects: Twelve children (8–14 years of age) with spastic hemiplegic cerebral palsy. Interventions: Subjects made fast reaching movements with the affected or nonaffected arm on a digitizer in three context conditions: (a) reach to press a light switch to turn on a red light ( functional), (b) reach to press the light switch; no light ( semi-functional), and (c) reach to a marker ( nonfunctional). Main outcome measures: Kinematics of reaching movements of affected and nonaffected arms: movement time (MT), peak velocity (PV), time to PV, percentage of MT where peak velocity occurred (PPV), and smoothness (i.e. number of movement units (MU)). Results: The functional condition elicited better quality of reaching for the nonaffected, but particularly the affected arm. Reaching of the affected arm was faster (larger MT; F = 10.21, p < 0.01), smoother (fewer MU; F = 19.95, p < 0.001), and better-controlled (right shift of PPV; F = 16.03, p < 0.001) compared with the semi and nonfunctional condition. Reaching of the nonaffected arm was also faster (longer MT, F = 4.81, p < 0.05), and more smooth (fewer MU, F = 7.23, p < 0.05). Conclusions: These findings suggest that providing a functional context to perform a task may enhance the quality of reaching movements of the affected arm in children with spastic hemiparesis.
Analyses of nursing home residents in hospice care using the Minimum Data Set
Authors: Buchanan Robert J , Choi Maryann , Wang Suojin , Huang Chunfeng 
Published: January 2003

Objective: To present comprehensive profiles of residents in hospice care at admission to the nursing home using the Minimum Data Set (MDS). Design and Setting: We analysed 40,622 MDS admission assessments for nursing home residents in hospice care. The MDS contains resident-focused data on pain, cognitive patterns, physical function, disease diagnoses, medications, nutrition, and specific treatments received. Results: About four in five recently admitted hospice residents had ‘do not resuscitate’ orders and only 27% had a living will. Over 70% of recently admitted hospice residents experienced pain, with almost one half experiencing daily pain. Over one half of those hospice residents in pain experienced moderate pain and almost one third experienced horrible or excruciating pain. About 57% of recently admitted hospice patients had cancer, 21% had congestive heart failure, 20% had emphysema/chronic obstructive pulmonary disease, and 18% had depression. About one in two recently admitted hospice residents exhibited at least moderate impairment in cognitive function. Conclusions: There is a need to improve pain management, advanced directives, and mental health services for residents dying in nursing homes.
Effect of cardiac cycle on ultrasound assessment of endothelial function
Authors: Chuang Michael L , Douglas Pamela S , Bisinov Elizabeth A , Stein James H 
Published: January 2003

To investigate the effects of non-ECG-triggered imaging during ultrasound studies of endothelial function, brachial artery diameters were measured throughout the cardiac cycle at rest, during reactive hyperemia, and after administration of nitroglycerin. R-wave-triggered imaging using a 7.5-MHz ultrasound transducer with acquisition every 41.7-66.7 ms was performed in 24 subjects. Cardiac cycle-related variation was computed as the maximum per cent change from the end-diastolic diameter. The range of possible errors in flow-mediated dilation (FMD) and nitroglycerin-mediated vasodilation that may result from ignoring cyclic variations in diameter was determined for each condition. True FMD, true nitroglycerin-mediated vasodilation, and the maximum and minimum values that could be erroneously calculated for FMD if timing was ignored all differed dramatically (p 0.05). The range of apparent FMD values that could be measured was nearly three times the true FMD value. Ignoring temporal position within the cardiac cycle artifactually increased calculated FMD into the normal range, despite truly impaired FMD. Peak arterial dilation occurred before end-systole and greater baseline vessel compliance was associated with greater FMD. Brachial arterial diameters vary significantly throughout the cardiac cycle. The magnitude of this variation is similar to the arterial dilation induced by reactive hyperemia and nitroglycerin, making ECG-triggered imaging mandatory for accurate and reproducible clinical and research measurements of artery diameters and FMD. Measurement of diameters at end-diastole may be preferred to other time-points in the cardiac cycle.
Enhanced anaerobic degradation of polymeric azo compounds by Escherichia coli in the presence of low-molecular-weight redox mediators
Authors: Rau J , Maris B , Kinget R , Samyn C , van den Mooter G , Stolz A 
Published: January 2003

Abstract
The effects of the redox mediator lawsone (2-hydroxy-1,4-naphthoquinone) on the ability of Escherichia coli to reduce anaerobically polymeric azo compounds were analysed. Two types of polymeric azo compounds were tested, that have been proposed as putative tools for the site-specific targeting of drugs to the colon. The first group of polymers consisted basically of linear chains of polymethacrylic acid or polymethylmethacrylate which were interrupted by subunits of 4,4′-bis-(methacryloylamino)azobenzene. These polymers differed significantly in their hydrophilicity according to the relative proportion of polymethacrylic acid used for the polymerization procedure. The second group of polymers consisted of almost water-insoluble poly(ether-ester)azo polymers that were composed of 4-(6-hydroxyhexyl)oxy-phenylazobenzoate and 16-hydroxyhexadecanoate. The addition of lawsone to the anaerobically incubated cultures of E. coli resulted in a pronounced increase in the reduction rates of the water-soluble poly(methacrylate-co-4,4′-bis(methacryloyl-amino)azobenzene) and in a much smaller, but significant, increase in the reduction rates of the hydrophobic poly(ether-ester)azo polymers. An increase in the amount of azo groups resulted, for the hydrophobic poly(ether-ester)azo polymers, in an increased reduction rate in the presence of the redox mediator lawsone.
Assessment of estrogenic activity in some common essential oil constituents
Authors: Howes M-J R , Houghton P J , Barlow D J , Pocock V J , Milligan S R 
Published: January 2003

Abstract
Estrogenic responses have not only been associated with endocrine function, but also with cognitive function. Several studies have indicated that estrogen replacement therapy has favourable effects on cognition, and may have potential in the prevention and treatment of Alzheimer's disease. Thus, ligands for the estrogen receptor, that have a better efficacy and adverse-effect profile than drugs currently available, require investigation. This study was undertaken to investigate the potential estrogenic activity of a number of essential oil constituents. Initially, estrogenic activity was determined by a sensitive and specific bioassay using recombinant yeast cells expressing the human estrogen receptor. At high concentrations, estrogenic activity was detected for citral (geranial and neral), geraniol, nerol and trans-anethole, while eugenol showed anti-estrogenic activity. Molecular graphics studies were undertaken to identify the possible mechanisms for the interaction of geranial, neral, geraniol, nerol and eugenol with the ligand-binding domain of the estrogen α-receptor, using the computer program HyperChem. Citral, geraniol, nerol and eugenol were also able to displace [3H]17β-estradiol from isolated α- and β-human estrogen receptors, but none of these compounds showed estrogenic or anti-estrogenic activity in the estrogen-responsive human cell line Ishikawa Var I at levels below their cytotoxic concentrations, and none showed activity in a yeast screen for androgenic and anti-androgenic activity. The potential in-vivo estrogenic effects of citral and geraniol were examined in ovariectomized mice, but neither compound showed any ability to stimulate the characteristic estrogenic responses of uterine hypertrophy or acute increase in uterine vascular permeability. These results show that very high concentrations of some commonly used essential oil constituents appear to have the potential to interact with estrogen receptors, although the biological significance of this is uncertain.
Rapid effect of progesterone on the contraction of rat aorta in-vitro
Authors: Zhang Meili , Wang G J , Benishin Christina G , Pang Peter K T 
Published: January 2003

Abstract
Progesterone induced rapid relaxation of KCl-induced contraction of rat aortic rings. The relaxant effect of progesterone on aortic rings was concentration-dependent (over the range of 10−10 to 10−5M) and partially dependent on the endothelium. Application of a nitric oxide (NO) synthase antagonist NG-monomethyl-L-arginine (L-NMMA, 10−5M) after progesterone treatment partially inhibited the relaxant effects of progesterone. This suggested that part of the effect was through the production of nitric oxide. Washing out the steroid hormone in the bath solutions could quickly reverse the inhibitory effects of progesterone on phasic tension generation in aortic rings. Five minutes after washout, the tension generation in aortic rings was completely restored. Cultured endothelial cells from rat aorta increased release of NO into culture media in response to a 60-min exposure to progesterone. Aldosterone and dexamethasone were also tested, and failed to relax KCl- induced contraction of aortic rings. These data suggest that the vascular effects of progesterone are not mediated by a genomic action of this steroid, and that the vascular effects are mediated partially through endothelial NO production.
Redox signaling in the growth and development of colonial hydroids
Authors: Blackstone Neil W. 
Published: January 2003

SUMMARY
Redox signaling provides a quick and efficient mechanism for clonal or colonial organisms to adapt their growth and development to aspects of the environment, e.g. the food supply. A `signature' of mitochondrial redox signaling, particularly as mediated by reactive oxygen species (ROS), can be elucidated by experimental manipulation of the electron transport chain. The major sites of ROS formation are found at NADH dehydrogenase of complex I and at the interface between coenzyme Q and complex III. Inhibitors of complex III should thus upregulate ROS from both sites; inhibitors of complex I should upregulate ROS from the first but not the second site, while uncouplers of oxidative phosphorylation should downregulate ROS from both sites. To investigate the possibility of such redox signaling, perturbations of colony growth and development were carried out using the hydroid Podocoryna carnea. Oxygen uptake of colonies was measured to determine comparable physiological doses of antimycin A1 (an inhibitor of complex III),rotenone (an inhibitor of complex I) and carbonyl cyanide m-chlorophenylhydrazone (CCCP; an uncoupler of oxidative phosphorylation). Using these doses, clear effects on colony growth and development were obtained. Treatment with antimycin A1 results in `runner-like'colony growth, with widely spaced polyps and stolon branches, while treatment with CCCP results in `sheet-like' growth, with closely spaced polyps and stolon branches. Parallel results have been obtained previously with azide, an inhibitor of complex IV, and dinitrophenol, another uncoupler of oxidative phosphorylation. Perhaps surprisingly, rotenone produced effects on colony development similar to those of CCCP. Assays of peroxides using 2′,7′-dichlorofluorescin diacetate and fluorescent microscopy suggest a moderate difference in ROS formation between the antimycin and rotenone treatments. The second site of ROS formation (the interface between coenzyme Q and complex III) may thus predominate in the signaling that regulates colony development. The fat-rich, brine shrimp diet of these hydroids may be relevant in this context. Acyl CoA dehydrogenase, which catalyzes the first step in the mitochondrial β-oxidation of fatty acids,carries electrons to coenzyme Q, thus bypassing complex I. These results support a role for redox signaling, mediated by ROS, in colony development. Nevertheless, other redox sensors between complexes I and III may yet be found.
The snakeheadChanna asiaticaaccumulates alanine during aerial exposure, but is incapable of sustaining locomotory activities on land through partial amino acid catabolism
Authors: Chew Shit F. , Wong Mei Y. , Tam Wai L. , Ip Yuen K. 
Published: January 2003

SUMMARYThe freshwater snakehead Channa asiatica is an obligatory air-breather that resides in slow-flowing streams and in crevices near riverbanks in Southern China. In its natural habitat, it may encounter bouts of aerial exposure during the dry seasons. In the laboratory, the ammonia excretion rate of C. asiatica exposed to terrestrial conditions in a 12h:12h dark:light regime was one quarter that of the submerged control. Consequently, the ammonia contents in the muscle, liver and plasma increased significantly, and C. asiatica was able to tolerate quite high levels of ammonia in its tissues. Urea was not the major product of ammonia detoxification in C. asiatica, which apparently did not possess a functioning ornithine urea cycle. Rather, alanine increased fourfold to 12.6μmolg-1 in the muscle after 48h of aerial exposure. This is the highest level known in adult teleosts exposed to air or an ammonia-loading situation. The accumulated alanine could account for 70% of the deficit in ammonia excretion during this period, indicating that partial amino acid catabolism had occurred. This would allow the utilization of certain amino acids as energy sources and, at the same time, maintain the new steady state levels of ammonia in various tissues, preventing them from rising further. There was a reduction in the aminating activity of glutamate dehydrogenase from the muscle and liver of specimens exposed to terrestrial conditions. Such a phenomenon has not been reported before and could, presumably, facilitate the entry of α-ketoglutarate into the Krebs cycle instead of its amination to glutamate, as has been suggested elsewhere. However, in contrast to mudskippers, C. asiatica was apparently unable to reduce the rates of proteolysis and amino acid catabolism, because the reduction in nitrogenous excretion during 48 h of aerial exposure was completely balanced by nitrogenous accumulation in the body. Alanine accumulation also occurred in specimens exposed to terrestrial conditions in total darkness, with no change in the total free amino acid content in the muscle. Exercise on land led to a decrease in glycogen content, and an increase in lactate levels, with no significant effect on ammonia and alanine contents in the muscle of C. asiatica. Hence, unlike the mudskipper Periophthalmodon schlosseri,C. asiatica was incapable of increasing the rate of partial amino acid catabolism to sustain locomotory activities on land. Alanine formation therefore appears to be a common strategy adopted by obligatory air-breathing fishes to avoid ammonia toxicity (not a strategy to detoxify ammonia) on land,but not all of them can utilize it to fuel muscular activities.
Biological impacts of deep-sea carbon dioxide injection inferred from indices of physiological performance
Authors: Seibel Brad A. , Walsh Patrick J. 
Published: January 2003

SUMMARYA recent proposal to store anthropogenic carbon dioxide in the deep ocean is assessed here with regard to the impacts on deep-living fauna. The stability of the deep-sea has allowed the evolution of species ill-equipped to withstand rapid environmental changes. Low metabolic rates of most deep-sea species are correlated with low capacities for pH buffering and low concentrations of ion-transport proteins. Changes in seawater carbon dioxide partial pressure (PCO2) may thus lead to large cellular PCO2 and pH changes. Oxygen transport proteins of deep-sea animals are also highly sensitive to changes in pH. Acidosis leads to metabolic suppression, reduced protein synthesis,respiratory stress, reduced metabolic scope and, ultimately, death. Deep-sea CO2 injection as a means of controlling atmospheric CO2levels should be assessed with careful consideration of potential biological impacts. In order to properly evaluate the risks within a relevant timeframe,a much more aggressive approach to research is warranted.
Maneuverability by the sea lionZalophus californianus: turning performance of an unstable body design
Authors: Fish Frank E. , Hurley Jenifer , Costa Daniel P. 
Published: January 2003

SUMMARYManeuverability is critical to the performance of fast-swimming marine mammals that use rapid turns to catch prey. Overhead video recordings were analyzed for two sea lions (Zalophus californianus) turning in the horizontal plane. Unpowered turns were executed by body flexion in conjunction with use of the pectoral and pelvic flippers, which were used as control surfaces. A 90° bank angle was used in the turns to vertically orient the control surfaces. Turning radius was dependent on body mass and swimming velocity. Relative minimum radii were 9-17% of body length and were equivalent for pinnipeds and cetaceans. However, Zalophus had smaller turning radii at higher speeds than cetaceans. Rate of turn was inversely related to turn radius. The highest turn rate observed in Zalophus was 690 degrees s-1. Centripetal acceleration measured up to 5.1 g for Zalophus. Comparison with other marine mammals indicates that Zalophus has a morphology that enhances instability,thus providing enhanced turning performance. Enhanced turning performance is necessary for sea lions to forage after highly elusive prey in structurally complex environments.
Central effects of various ligands on drinking behavior in eels acclimated to seawater
Authors: Kozaka Tomohiro , Fujii Yasuaki , Ando Masaaki 
Published: January 2003

SUMMARYIntracranial injection of eel angiotensin II (eANG II,5×10-13-5×10-8 mol), acetylcholine (ACh,5×10-12-5×10-9 mol), substance P(5×10-10 mol) and isoproterenol (a β-adrenoceptor agonist, 5×10-11-5×10-9 mol) enhanced water intake in the seawater eel. The effects of eANG II, ACh and isoproterenol were dose-dependent. By contrast, water intake was inhibited by intracranial injection of eel atrial natriuretic peptide (eANP,5×10-13-5×10-10 mol), serotonin (5-HT,5×10-12-5×10-8 mol), ghrelin(5×10-12-5×10-10 mol), γ-amino butyric acid (GABA, 5×10-11-5×10-8 mol), prolactin(PRL, 5×10-10-5×10-9 mol), arginine vasotocin (AVT, 5×10-12 mol), vasoactive intestinal peptide(VIP, 5×10-11 mol), noradrenaline (5×10-9mol l-1) and phenylephrine (α-adrenoceptor agonist,5×10-11-5×10-9 mol). The inhibitory effects of eANP, 5-HT, ghrelin, GABA, PRL and phenylephrine were dose-dependent. The intracranial stimulatory effect of eANG II was relatively long-lasting compared with the intravenous effect. The stimulatory effect of intravenous eANG II disappeared immediately, and was followed by an inhibition, which could be well explained by an increase in eANP secretion from the atrium.
Mechanics of cuticular elastic energy storage in leg joints lacking extensor muscles in arachnids
Authors: Sensenig Andrew T. , Shultz Jeffrey W. 
Published: January 2003

SUMMARYCertain leg joints in arachnids lack extensor muscles and have elastically deformable transarticular sclerites spanning their arthrodial membranes, an arrangement consistent with a model in which flexor muscles load transarticular sclerites during flexion and energy from elastic recoil is used for extension. This study quantifies the potential contribution of elastic recoil to extension torque at joints of the fourth leg of representative arachnids. Extension torques of isolated joints with and without transarticular sclerites were measured as the joint was rotated through angles and at angular velocities comparable with those used by walking animals. The procedure was repeated with the joint subjected to different internal fluid pressures in order to assess the potential role of hydraulically induced extension.The efficiency of elastic energy storage (resilience) in the absence of internal fluid pressure was 70-90% for joints with well-developed transarticular sclerites, and the magnitude of torque was similar to those produced by different joint extension mechanisms in other arthropods. Increased internal fluid pressure acted synergistically with transarticular sclerites in some joints but had little or no effect in others. Joints that lacked both extensor muscles and transarticular sclerites appeared to be specialized for hydraulic extension, and joints operated by antagonistic muscles lacked apparent specializations for either elastic or hydraulic extension. It is well known that elastic energy storage is a significant contributor to propulsion in running vertebrates and certain arthropods, where elastic elements are loaded as the center of mass falls during one phase of the locomotor cycle. However, transarticular sclerites are apparently loaded by contraction of flexor muscles when the leg is not in contact with the substratum. Hence the mechanism of a transarticular sclerite is more similar to the flight and jumping mechanisms of other arthropods than to running vertebrates. The evolutionary significance and potential mechanical advantages of the transarticular elastic mechanism are discussed.
Measuring wing kinematics, flight trajectory and body attitude during forward flight and turning maneuvers in dragonflies
Authors: Wang Hao , Zeng Lijiang , Liu Hao , Yin Chunyong 
Published: January 2003

SUMMARYA robust technique for determining the wing kinematics, body position and attitude of a free-flight dragonfly is described. The new method is based on a projected comb-fringe technique combined with the natural landmarks on a dragonfly, allowing us to establish the local body-centered coordinate system with high accuracy, and to measure the body attitude at any instant. The kinematic parameters, including wingbeat frequency, flapping angle, angle of attack, torsional angle and camber deformation, required no assumptions to be made with respect to wing geometry, deformability (except the assumption of rigid leading edges) or bilateral wing symmetry. Two typical flight behaviors,forward flight and turning maneuvers, of dragonflies Polycanthagyna melanictera Selys were measured and analyzed.
Oligonuclear Metal-Assembly of Antiferromagnetic Ni4 and Ferromagnetic Ni6 Clusters with Non-Schiff-Base Tetradentate Ligand
Authors: Mikuriya Masahiro , Tanaka Kumiko , Inoue Nozomi , Yoshioka Daisuke , Lim Jong-Wan 
Published: January 2003

Abstract
Tetranuclear and hexanuclear nickel(II) complexes with N,N′-bis(2-hydroxy-3,5-dimethylbenzyl)-N,N′-dimethyl-1,2-ethanediamine (H2L), [Ni4L2(CH3COO)4]·4THF and [Ni6L3(OH)4(NO3)2(H2O)2]·2DMF, have been synthesized and characterized by X-ray crystallography, electronic spectroscopy and magnetic susceptibility measurement.
Haemangiopericytoma of the submental region
Authors: Constantinides H. , Toh C. , Warfield A. T. , Johnson A. P. 
Published: January 2003

Haemangiopericytoma refers to an uncommon vascular/perivascular neoplasm of which a minority of cases arise in the head and neck. It comprises a group of lesions with marked clinical and pathological heterogeneity and a lack of positive criteria by which to make a definitive diagnosis.We describe an unusual case of such a tumour in the submental region, review its pathological features and discuss issues in management and prognosis.