bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ca2+ signals and T lymphocytes “New mechanisms and functions in Ca2+ signalling”
Authors: Randriamampita C. , Trautmann A. 
Published: January 2004

Abstract Interaction between a T cell and an antigen‐presenting cell leads to the rapid formation of an immunological synapse allowing antigen detection by the T cell and the development of an immune response. Antigen detection triggers various cellular responses including a modest but sustained T cell Ca2+ increase. In this review are discussed a series of related questions. What are the various molecular events by which a T cell Ca2+ response can be triggered in the immunological synapse by a very small amount of antigen ? How is Ca2+ released from intracellular stores and how can these stores remain empty for hours ? Through which channels does Ca2+ influx takes place, and how is Ca2+ influx coupled to Ca2+ release from intracellular stores ? What are the main immediate and indirect cellular targets of the Ca2+ increase ?
Yessotoxin affects fMLP‐induced cell shape changes inMytilus galloprovincialis immunocytes
Authors: Malagoli Davide , Ottaviani Enzo 
Published: January 2004

AbstractUsing computer‐assisted microscopic image analysis, we have found that algal yessotoxin (YTX) affects the immune response of Mytilus galloprovincialis. Indeed, YTX increases immunocyte cell motility through the involvement of both extracellular Ca2+and cAMP, but not through protein kinase A, protein kinase C or phosphoinositide 3‐kinase. Alone, however, the toxin does not induce any effect, as its action on cell motility is observed only after addition of the chemotactic substance N‐formyl‐Meth‐Leu‐Phe (fMLP). fMLP is known to induce cellular changes via both the phosphatidylinositol and cAMP pathways and, from this scenario, we can surmise that Ca2+and cAMP concentrations rise sufficiently in fMLP‐activated immunocytes to reveal YTX action. One possible explanation is that the toxin increases fMLP‐mediated cell activation by intervening in L‐type Ca2+‐channel opening through a cAMP‐dependent/PKA‐independent pathway.
Muscarinic acetylcholine receptors involved in the regulation of neural stem cell proliferation and differentiation in vitro
Authors: Zhou Chang , Wen Zhe‐xing , Shi Dong‐mei , Xie Zuo‐ping 
Published: January 2004

AbstractNeural stem cells (NSCs) are currently considered powerful candidates for cell therapy in neurodegenerative disorders such as Parkinson's disease. However, it is not known when and how NSCs begin to differentiate functionally. Recent reports suggest that classical neurotransmitters such as acetylcholine (Ach) are involved in the proliferation and differentiation of neural progenitor cells, suggesting that neurotransmitters play an important regulatory role in development of the central nervous system (CNS). We have shown by calcium imaging and immunochemistry that proliferation and differentiation are enhanced by M2 muscarinic Ach receptors (mAchR) expressed on the NSC surface and on their neural progeny. Moreover, atropine, an mAchR antagonist, blocks the enhancement and inhibits the subsequent differentiation of NSCs. Further understanding of this neural‐nutrition role of Ach might elucidate fetal brain development, the brain's response to injury, and learning and memory.
Primary cilia in vertebrate corneal endothelial cells
Authors: Collin Shaun P. , Collin H. Barry 
Published: January 2004

AbstractThe presence of primary cilia in corneal endothelial cells of a range of species from six non‐mammalian vertebrate classes (Agnatha, Elasmobranchii, Amphibia, Teleostei, Reptilia and Aves) is examined by scanning and transmission electron microscopy. Our aim is to assess whether these non‐motile cilia protruding into the anterior chamber of the eye are a consistent phylogenetic feature of the corneal endothelium and if a quantitative comparison of their morphology is able to shed any new light on their function. The length (0.42–3.80 μm) and width (0.12–0.44 μm) of the primary cilia varied but were closely allied with previous studies in mammals. However, interspecific differences such as the presence of a terminal swelling in the Teleostei and Amphibia suggest there are functional differences. Approximately one‐third of the endothelial cells possess cilia but the extent of protrusion above the cell surface varies greatly, supporting a dynamic process of retraction and elongation. The absence of primary cilia in primitive vertebrates (Agnatha and Elasmobranchii) that possess other mechanisms to control corneal hydration suggests an osmoregulatory and/or chemosensory function.
Influence of initial fixation protocol on the appearance of primary cilia on the rabbit corneal endothelial cell apical surface as assessed by scanning electron microscopy
Authors: Doughty Michael J 
Published: January 2004

AbstractThe objective was to examine primary cilia at the apical surface of corneal endothelial cells after using different fixatives. Female albino rabbits (2 kg) were euthanised at 15:00 h and the corneas fixed immediately (usually with an isotonic 2% glutaraldehyde—cacodylate fixative) either after dissection, by application fixative at 4 °C, by immersion of the eyeball in fixative at room temperature (RT), or by application of an isotonic or a hypertonic (Karnovsky‐type) fixative at RT. Images at 2000× were taken from the central corneal region, and number and length of primary cilia assessed. The length was the same regardless of method (overall average of 1.67±0.70 μm), but the incidence of primary cilia was hypertonic fixative (87% of cells) >cold drop fixation (71%), >whole globe immersion (68%) >dissect then fix methods (67%) >RT drop fixation (34%). The first four methods however yielded cells with unacceptable artefacts (especially distortion). More details should be provided of the primary fixation method used.
Aspects of nitrogen use efficiency of cauliflower I. A simulation modelling based analysis of nitrogen availability under field conditions
Authors: KAGE H. , ALT C. , STÜTZEL H. 
Published: January 2004

Data from several field experiments (eight crops grown under a widely varying nitrogen supply on a loess loam soil) were used for a simulation modelling based analysis of nitrogen availability of cauliflower. The model was built out of components describing root growth, nitrate transport to the roots and the vertical nitrate transport within the soil.Root observations obtained over 2 years indicated an increased fraction of dry matter allocated to the fine roots under N deficiency. An adopted version of a root growth model for cauliflower described the rooting data with an R2=0·75. Based upon an acceptable description of the soil water budget, vertical nitrate movement during the growth period of cauliflower was accurately described. The magnitude of this movement, however, was limited to soil depths of about 60 cm even after periods of high rainfall, because of a high soil water holding capacity. An analysis of the factors determining nitrate availability indicated that apparent mass flow was only of high importance for conditions of extremely high N supply where high amounts of nitrate nitrogen remain in the soil up to the end of the growing season. Otherwise, the dominating fraction of nitrate has to be transported to the roots by diffusion. Single root model based calculations of maximum nitrate transport to roots overestimated N availability as indicated by estimates of critical soil nitrate N that were too low. The introduction of a restricted uptake activity period of the roots was used to bridge the gap between theoretical calculations and empirical results. Scenario calculations were carried out to obtain functional relationships between N supply and residual soil nitrate levels for different soil conditions and management practices.
Precession-driven migration of water in the surficial layers of Mars
Authors: Tokano Tetsuya 
Published: January 2004

A linear correlation analysis between the Mars Odyssey neutron fluxes and various surface parameters indicates that the annual maximum surface temperature is the most important factor controlling the soil water content in the surficial (upper few tens of centrimetres) layers of the Martian soil. This is likely to be associated with the higher enthalpy of hydration of minerals in comparison with the enthalpy of sublimation of ice, which is presumably almost absent in the surficial layer. While presently the maximum surface temperature occurs near 30° S because of perihelion in late southern spring, the season of perihelion periodically migrates by virtue of precession. Consequently, the maximum surface temperature as well as the driest place on Mars should move from one hemisphere to the other with a period of about 51 000 yr. A significant amount of surficial (adsorbed) water would then be exchanged between the hemispheres and between the soil and other reservoirs, especially the polar caps and the polar layered deposits, and is probably borne out by the stratigraphic structure of these deposits. It is suggested that the water migration driven by the orbital eccentricity and precession may be as important as the obliquity-driven exchange of water, particularly very close to the surface, where ground ice is unstable.The zones of liquid water stability oscillate somewhat in a north–south direction in the course of the precession cycle, but are most prevalent in parts of the low and mid northern latitudes as well as in the Hellas Basin. The thermal stability of liquid water tends to be high where the near-surface soil water content is low, indicating that the periodic melting of ground ice by solar heating is not a likely source of liquid water on the surface, but some episodic processes should provide water, if any.An enhanced soil water content near the surface is always accompanied with a reduced peak ultraviolet flux, both reducing the chemical reactivity of the soil. In the present epoch the northern hemisphere may represent astrobiologically more clement environmental conditions.
Intravasal microdialysis is superior to intramyocardial microdialysis in detecting local ischaemia in experimental porcine myocardial infarction
Authors: Bäckström T. , Franco‐Cereceda A. 
Published: January 2004

AbstractObjective:  A novel application of microdialysis was studied, where myocardial outflow of energy metabolites was monitored by intravasal microdialysis in the myocardial venous outflow during ischaemia and reperfusion. These levels where related to levels monitored by microdialysis catheters placed intramyocardially.Methods:  Microdialysis catheters were introduced into the great cardiac vein (GCV), ischaemic myocardium and non‐ischaemic myocardium in 10 anaesthetized pigs. The left anterior descending coronary artery was occluded for 60 min in five pigs and five pigs served as controls. Ischaemia was followed by 120 min of reperfusion. Microdialysis samples were analysed for glucose, lactate, pyruvate and glycerol. Venous lactate and glucose levels were measured by blood samples from the femoral vein.Results:  All animals subjected to ischaemia developed myocardial infarction. Lactate, lactate/pyruvate ratio and glycerol increased in the microdialysis samples from the GCV and the catheter placed in ischaemic myocardium while no changes were detected in samples from the catheter placed in the non‐ischaemic myocardium.Conclusion:  In this study, we have demonstrated that intravasal microdialysis catheters rapidly and reliably detect local myocardial ischaemia, while intramyocardially placed microdialysis catheters will not show these changes if placed in a non‐ischaemic area.
Stimulation of HSP72 expression following ATP depletion and short‐term exercise training in fast‐twitch muscle
Authors: Ecochard L. , Roussel D. , Sempore B. , Favier R. 
Published: January 2004

AbstractAim:  Previous data have reported increases in HSP72 expression in skeletal muscles after endurance training but the physiological and biochemical signals that induce HSP72 accumulation remain largely unknown. In this study, we tested the hypothesis that energy status is a key regulatory event for HSP72 accumulation in skeletal muscles.Methods:  Reduction of high‐energy phosphate levels was induced by supplementation with a creatine analogue, beta‐guanidinopropionic acid (GPA) for 3 weeks while control rats received distilled water in the same conditions. Half of the animals were kept sedentary while the others were submitted to a short‐term (2 weeks) training program on a treadmill (30 m min−1, 0% slope; 50–70 min day−1).Results:  GPA supplementation resulted in a large drop (∼50%) in adenosine triphosphate (ATP) level in both fast and slow muscles whether the animals were trained or remained sedentary. HSP72 level did not change with GPA alone, but the training‐induced increase in HSP72 level was strongly enhanced by superimposition of GPA diet in fast but not in slow skeletal muscles. The changes in HSP72 level were not linked to changes in fibre typology and/or mitochondrial capacities.Conclusions:  The results of the present investigation indicate that levels of high‐energy phosphate per se do not play a direct role in determining HSP72 level in skeletal muscles. However, during superimposition of training to GPA, then the adaptive strategy of fast‐twitch muscle (e.g. plantaris) seems to be directed towards appearance of some properties of red, oxidative fibres (increase in oxidative capacities and HSP72 level).
Effect of anaesthetic and rat strain on heart rate responses to simulated haemorrhage
Authors: Holobotovskyy V. V. , Arnolda L. F. , McKitrick D. J. 
Published: January 2004

AbstractAim and methods:  Haemorrhage is characterized by two distinct responses, sympathoexcitation that evokes tachycardia and supports blood pressure, followed by sympathoinhibition contributing to bradycardia and hypotension. It has been shown that anaesthetics alter the response to haemorrhage and we hypothesized that rat strain may also influence the response. We investigated the effect of simulated haemorrhage on heart rate (HR) responses in three strains of conscious rats, and the effect of three common anaesthetics, by comparing HR responses under anaesthesia to the conscious response. Haemorrhage was simulated by constricting the inferior vena cava. We demonstrate differential effects of anaesthetics, including both maintenance and elimination of HR responses to haemorrhage depending on anaesthetic.Results:  We also show that both phases of the HR response differ in different conscious rat strains, and we have demonstrated a transient increase in HR during the decompensatory phase of haemorrhage, a novel ‘second HR peak’ with advanced hypotension.Conclusion:  Both rat strain and anaesthetic influence HR responses to haemorrhage, and some anaesthetics appear less suitable than others for studies of haemodynamic responses in rats. There was evidence of an additional compensatory mechanism that operates at advanced levels of hypotension in the rat.
Sweating responses during activation of the muscle metaboreflex in humans is altered by time of day
Authors: Aoki K. , Kondo N. , Shimomura Y. , Yokoi M. , Iwanaga K. , Harada H. , Katsuura T. 
Published: January 2004

AbstractAim: The aim of the present study was to test for a time‐of‐day effect on sweating responses to activation of the muscle metaboreflex.Methods: Eight male subjects each participated in two exercise sessions, one in the morning and one in the evening. Within each session there were two 60‐s bouts of isometric handgrip (IHG) exercise at 50% maximal voluntary contraction. Prior to IHG, whole body warming by a water‐perfused suit initiated mild sweating. The first bout of IHG exercise began at 06.00 hours (am) and 18.00 hours (pm). Blood circulation to the forearm was occluded for 120 s, beginning 5 s before the end of the second bout of IHG to activate the muscle metaboreflex.Results: During both bouts of exercise, sweating rate (SR) on both the chest and right forearm significantly increased from the pre‐exercise period in bothamandpmsessions. SR rapidly decreased during first minute of recovery after the first bout of IHG exercise. However, during post‐exercise ischaemia (PEI) after the second bout of IHG exercise, SR was maintained significantly above the pre‐exercise level only in thepmsession. The increases in SR on the chest and right forearm during PEI were significantly greater in thepm, than in theam, session. However, SR of the palm was not maintained during PEI.Conclusions: We conclude that under mild hyperthermic conditions, the sweating response in non‐glabrous skin to activation of the muscle metaboreflex exhibits a time‐of‐day effect.
Reopening of L‐type calcium channels in human ventricular myocytes during applied epicardial action potentials
Authors: Fülöp L. , Bányász T. , Magyar J. , Szentandrássy N. , Varró A. , Nánási P. P. 
Published: January 2004

AbstractAims:  Present study was performed to compare the dynamics of human L‐type calcium current (ICa,L) flowing during rectangular voltage pulses, voltage ramps, and action potentials (APs) recorded from epicardiac and endocardiac canine ventricular cells.Methods:  I
Ca,L was recorded in single myocytes isolated from undiseased human hearts using the whole cell voltage clamp technique.Results:  The decay of ICa,L was monotonic when using rectangular pulses or endocardial APs as voltage commands, whereas the current became double‐peaked (displaying a second rise and fall) during epicardial (EPI) APs or voltage ramps used to mimic EPI APs. These ICa,L profiles were associated with single‐hooked and double‐hooked phase‐plane trajectories, respectively. No sustained current was observed during the AP commands. Kinetics of deactivation and recovery from inactivation of human ICa,L were determined using twin‐pulse voltage protocols and voltage ramps, and the results were similar to those obtained previously in canine cells under identical experimental conditions.Conclusions:  I
Ca,L can inactivate partially before and deactivate during the phase‐1 repolarization of the epicardiac AP, and reopening of these channels seems to be associated with formation of the dome.
Stretch reflex excitability of the anti‐gravity ankle extensor muscle in elderly humans
Authors: Kawashima N. , Nakazawa K. , Yamamoto S.‐I. , Nozaki D. , Akai M. , Yano H. 
Published: January 2004

AbstractAim:  To examine whether the stretch reflex excitability of the soleus muscle changes with age, stretch reflexes at rest (REST) and during weak voluntary contractions (ACT) were elicited in 18 older and 14 younger subjects.Method:  The amplitude of the stretch reflex responses and gain, defined as the gradient of the regression line for the relation between stretch reflex responses against the angular velocity of the applied perturbation, were evaluated in each short‐latency (M1) and two long‐latency components (M2 and M3).Results:  It was found that in the older group, both the amplitude and gain of the M1 component did not change from the REST to the ACT conditions, whereas in the younger group both variables significantly increased from the REST to ACT conditions. The latency of the M1 component was significantly shorter under the REST condition (older vs. younger: 51.8 ± 7.37 vs. 55.1 ± 8.69 ms), while no group differences were found in those variables under the ACT condition, suggesting that the muscle‐tendon complexes of SOL muscles of the older subjects were less elastic and had less slack, probably due to age‐related histochemical alterations. Further, the Hoffman reflex (H‐reflex), elicited during the REST condition in 10 older and 11 younger subjects showed no significant differences, suggesting that the soleus motoneuron response to the Ia input was comparable between the two subject groups.Conclusion:  The histochemical alterations occurring with the ageing process might augment the short‐latency stretch reflex in the SOL muscle without enhancement of motoneuronal excitability, and this effect might be masked when the muscle is voluntarily activated.
Effective high‐dose chemotherapy combined with CD34+‐selected peripheral blood stem cell transplantation in a patient with cutaneous involvement of nasal NK/T‐cell lymphoma
Authors: Koizumi Kazuki , Fujimoto Katsuya , Haseyama Yoshihito , Endo Tomoyuki , Nishio Mitsufumi , Yokota Kouichi , Itoh Tomoo , Sawada Ken‐ichi , Koike Takao 
Published: January 2004

Abstract:The prognosis of nasal natural killer (NK)/T‐cell lymphoma with cutaneous involvement especially is morbid despite intensive chemotherapy and radiotherapy. We treated a 52‐yr‐old Japanese woman with cutaneous dissemination of nasal NK/T‐cell lymphoma. Six cycles of chemotherapy, irradiation to skin lesion were administered and complete remission (CR) was attained. High‐dose chemotherapy (HDC; etoposide 750 mg/m2 × 2 d, cyclophosphamide 60 mg/kg × 2 d, total body irradiation 12 Gy two daily fractions × 3 d) followed by CD34+‐selected autologous peripheral blood stem cell transplantation (CD34+‐APBSCT) was then prescribed. Complete remission (CR) was obtained and she has been free of disease for 34 months since CD34+‐APBSCT. We suggest that marrow‐ablative chemotherapy facilitated by autologous stem cell transplantation should be considered part of the primary therapy for subjects with a poor prognosis for nasal NK/T‐cell lymphoma with cutaneous involvement.
Quality of life and brain function following high‐dose recombinant human erythropoietin in low‐risk myelodysplastic syndromes: a preliminary report
Authors: Clavio Marino , Nobili Flavio , Balleari Enrico , Girtler Nicola , Ballerini Filippo , Vitali Paolo , Rosati Paola , Venturino Claudia , Varaldo Riccardo , Gobbi Marco , Ghio Riccardo , Rodriguez Guido 
Published: January 2004

Abstract:Objective:  In this prospective study we evaluate the effects of high‐dose recombinant human erythropoietin (rHuEPO) on quality of life (QOL) and brain function in patients with low‐risk myelodysplastic syndromes (MDS) (<10% marrow blasts). Preliminary data are reported.Methods:  Eleven consecutive patients were given rHuEPO (40 000 IU two times a week) for 12 wk. Responsive patients continued with 40 000 IU/wk for further 12 wk. Changes in QOL were assessed by the Functional Assessment of Cancer Therapy‐Anemia (FACT‐An) self‐report. Neurophysiological evaluation at the start of the therapy (t0) included duplex scanning of neck vessels, transcranial Doppler sonography (TCD), a complex neuropsychological evaluation, and quantitative electroencephalography (qEEG). Eight patients completed the neurophysiological evaluation after 24 wk (t1).Results:  Six patients (55%) achieved an erythroid response after 12 wk, which was maintained after 24 wk of treatment. FACT‐An score showed a relevant improvement between t0 and t1 in these patients. At baseline, TCD showed a mean cerebral blood flow (CBF) velocity in the upper normal range. Abnormalities in brain function were observed in five patients. In the eight patients who were re‐evaluated at t1, improvement was observed in three responding patients, two of them with abnormal values at t0. A strict correlation between QOL and neurophysiological improvements was not observed.Conclusions:  A high‐dose induction phase with rHuEPO followed by maintenance therapy may be an effective therapeutic schedule for low‐risk MDS patients. The erythroid response was associated with positive changes in the QOL. Neurophysiological improvements occurred only in a part (50%) of responding patients, mainly those who showed altered results at baseline.