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  • 1
    ISSN: 1432-1041
    Keywords: alfuzosin ; prazosin ; alpha1-adrenoceptor antagonist ; noradrenaline ; pharmacokinetics ; pharmacodynamics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In an open dose ranging study with random inclusion of placebo, alfuzosin (α1-adrenoceptor antagonist) 1, 2.5 and 5 mg was administered to 6 healthy volunteers, 3 of the volunteers received 10 mg alfuzosin. Supine systolic blood (SBP) pressure was not reduced by alfuzosin although significant increases occurred in supine heart rate (HR) after 2.5 and 5 mg. In the standing position, SBP was reduced at 2 and 4 h with 5 mg alfuzosin; significant increases in HR occurred following 1, 2.5 and 5 mg at 2, 4, 6 and 8 h after administration. Exercise SBP was not reduced; diastolic blood pressure was significantly reduced at 4 and 6 h with 5 mg alfuzosin. More marked effects were seen in the 3 subjects who received 10 mg alfuzosin. After 1 and 5 mg, tmax ranged from 1–2 h; Cmax (4.1 to 20.8 ng · ml−1; AUC (0–24) 20 to 132 ng · ml−1 · h (1 and 5 mg respectively) increased progressively with dose indicating dose dependent kinetics; no significant changes occurred in the visual analogue scale for sedation. A comparison of alfuzosin 5 mg, prazosin 1 mg and placebo each administered for 4 days, indicated that alfuzosin did not significantly reduce standing SBP on either Day 1 or Day 4; prazosin reduced SBP at 2 and 4 h on Day 1 and 6 h on Day 4 compared to placebo. Standing HR was increased by alfuzosin at 2 h on Day 1 and Day 4; increases occurred with prazosin at 2, 4, 6 and 8 h on Day 1 and 6 h on Day 4. Supine plasma noradrenaline increased with alfuzosin and prazosin at 2 and 4 h on Days 1 and 4; the increases were not significantly different. The plasma elimination half-life (t1/2) for alfuzosin was 3.4 h and 3.1 h after acute and chronic administration; (t1/2) for prazosin was 2.6 and 2.9 h. In conclusion alfuzosin causes small reductions in systolic blood pressure, accompanied by a dose dependent increase in heart rate in the supine and standing position and following exercise.
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  • 2
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Glutamate (10–100 μM) reversibly depolarizes guinea-pig cerebral cortical synaptosomes. This does not appear to be because of a conventional autoreceptor. Neither kainate at 1 mM, 100 μMn-methyl-D-aspartate (NMDA), 100 μM L-2-amino-4-phosphonobutanoate (APB), nor 100 μM quisqualate affects the Ca2+-dependent release of glutamate from suboptimally depolarized synaptosomes. However, kainate, quisqualate, and the quisqualate agonists β-N-ox-alylamino-L-alanine and α-amino-3-hydroxy-5-methylisox-azole propionate cause a slow Ca2+-independent release of glutamate from polarized synaptosomes. However, unlike kainate, quisqualate does not inhibit the acidic amino acid carrier. APB, NMDA, and the NMDA receptor-mediated neurotoxin β-N-methylamino-L-alanine do not influence Ca2+-independent release at 100 μM. The depolarization of the plasma membrane by glutamate can be mimicked by D-aspartate, can be blocked by the transport inhibitor dihydro-kainate, and is accompanied by the net uptake of acidic amino acids. L-Glutamate or D-aspartate at 100 μM increases the cytoplasmic free Ca2+ concentration. D-aspartate at 100 μM causes a Ca2+-dependent release of endogenous glutamate, superimposed on the Ca2+-independent heteroexchange with glutamate through the acidic amino acid carrier. The results suggest that the glutamatergic subpopulation of synaptosomes can be depolarized by exogenous glutamate.
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  • 3
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Potential exposure to pesticide residues resulting from burning wood treated with phenoxy and pyridine herbicides was assessed. Wood samples from trees treated with 2,4-D [2,4-dichlorophenoxy acetic acid], dicamba [3,6-dichloro-o-anisic acid], dichlorprop [2-(2,4-dichlorphenoxy) propionic acid], picloram [4-amino-3,5,6-trichloropicolinic acid], and triclopyr (3,5,6-trichloro-2-pyri dinyl)oxy acetic acid contained variable amounts of parent compound residues at 4, 8, and 12 months after application. At the time of the latter sampling, residues of 2,4-D, dicamba, and picloram were 〈2.1 mg/kg on a fresh weight basis. Mean residue concentrations of triclopyr and dichlorprop were somewhat higher at 3.5 and 13.0 mg/kg, respectively. In a laboratory experiment, samples with known amounts of herbicide residue were subjected to either slow or rapidly burning conditions in a tube furnace. During slow combustion, relatively stable compounds such as 2,4-D, dicamba, and dichlorprop were released in significant amounts. Rapid combustion greatly enhanced decomposition of 2,4-D, dicamba, dichlorprop, picloram, and triclopyr. A well-developed fire in a wood stove or fireplace, with active flaming combustion, where temperatures commonly reach 800–l,000°C, should result in greater than 95% thermal decomposition of the herbicides examined in this study. Burning of herbicide-treated wood under smoldering conditions could result in very low levels of herbicide residue in ambient indoor air. However, the exposure levels are less than 0.3% of the threshold limit value for 2,4-D and triclopyr. The exposure is also more than 3 orders of magnitude lower than the established acceptable daily intakes for these products.
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  • 4
    ISSN: 1600-0560
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A case of primitive neuroectodermal tumor of an 81-year-old man is presented, which was located in the cutis. The occurrence in this age and this superficial location is unusual and raises wide differential diagnostic possibilities. The tumor demonstrated Homer Wright rosettes, was positive for neuron-specific enolase and ultrastructurally revealed neurosecretory granules. These features support the diagnosis of a peripheral neuroblastoma. We discuss the controversy about the terminology of peripheral neuroblastoma vs. neuroepithelioma, as well as the differential diagnosis of these tumors.
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  • 5
    ISSN: 1420-908X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Exposure of the urinary bladder of rats to chemical irritants such as turpentine produces a long lasting inflammatory response. Chemosensitive primary afferent fibres supplying the bladder are excited by the irritants. Dorsal horn cells in L6, S1 are also excited, and show slowly developing and persistent increases in ongoing activity, responses to electrical stimulation of vesical afferents and distension of the bladder. These changes may provide an explanation for the sensory and reflex disturbances that occur in cystitis in man.
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 339 (1989), S. 592-592 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] "Of all the objects located beyond our Galaxy, only one, the great spiral nebula in Andromeda, can be glimpsed by the unaided eye in the northern celestial hemisphere." Thus begins Extragalactic Astronomy by Professor Vorontsov-Vel'yaminov of the Sternberg Astronomical Institute, Moscow University, ...
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  • 7
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The oxygen and carbon dioxide transporting properties of the haemolymph from an amphibious Australian crab,Holthuisana transversa were investigated. Within the temperature range 15 to 35°C increasing temperature markedly decreased oxygen affinity (ΔH=−54 kJ·mol−1). The Bohr effect was small at all temperatures with a mean value of −0.13. Over the temperature range 15–35°C there was a significant increase in the cooperativity of oxygen binding. Changing the concentration of Ca,l-lactate or haemocyanin in the haemolymph could elicit no significant change in either O2 affinity or cooperativity of O2 binding. There was no evidence in support of a specific effect of CO2 on oxygen affinity of either non-dialysed or dialysed haemolymph. The amount of CO2 that could be carried byH. transversa haemolymph was significantly reduced by increased temperature (approx. 14 to 12.5 mmol·l−1 CO2). Comparisons of oxygenated and deoxygenated haemolymph at a fixed pH were unable to demonstrate the presence of a significant Haldane effect. Combining data from oxygenated and deoxygenated haemolymph the buffer value was calculated to be in the range −6.2 to −8.5 mmol·l−1 HCO 3 − ·pH unit−1. The insensitivity ofH. transversa haemocyanin function to all modulating influences except temperature is discussed with respect to the ecology of this crab.
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  • 8
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Wild populations of white suckers (Catostomus commersoni) were exposed to a fluctuating ambient pH regime (pH 7 to 4 to 7 to 4) in natural soft water. Blood and muscle ionic composition together with the net flux rate of acid-base equivalents, other ion transfers as well as unidirectional Na+ and Cl− exchanges were measured simultaneously in intact fish. Exposure to a shift in water pH from 7 to 4 for 12 h resulted in a marked net influx of both H+ (or loss of base) and SO 4 2− concomitant with net losses of other major body ions (Na+, Cl−, K+, Ca2+, Mg2+) as well as inhibition of gill NaCl influx and stimulation of gill diffusional efflux, depressed plasma ion levels (Na+, Cl−, Ca2+) and epaxial white muscle intracellular ion loss (K+, Mg2+). These responses slowly reversed when the water pH was elevated back to pH 7 for 12 h. Complete recovery was not achieved for some variables, however, even by 48 h. The responses upon re-exposure to water pH 4 for 12 h paralleled those seen during the initial acid exposure period, indicating that the introduction of a short period of neutral pH between two periods of acid exposure, was not ameliorative. Exposure to a fluctuating ambient pH regime, therefore, seemed to be more detrimental to the fish than continued, gradual or prior acid exposure. A regression analysis was performed on the ion transfer rates measured simultaneously in individual fish over the fluctuating pH regime. The results showed that exchange diffusion appears to be an important mechanism of NaCl transfer in white suckers and that the net flux rate of acid/base equivalents via the gill is closely correlated with the difference between all major cation (Na+, K+, Ca2+, Mg2+) and anion (Cl−, SO 4 2− ) net transfer rates.
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  • 9
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 336 (1988), S. 530-530 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] CONSIDER the following paradox. Studies are made of a kangaroo hopping and a man running. Both are filmed using highspeed cine cameras, and both run over force platforms capable of measuring the ground reaction force. Calculations based on the measurements show that the energy lost and regained per ...
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  • 10
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] At present, quasars are the only objects that can be found in significant numbers at large redshifts and are useful in a variety of studies related to the early history of the Universe. Individual quasars are interesting in themselves and they may also be used as probes, to study the properties of ...
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