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  • 1980-1984  (7)
  • 1
    Electronic Resource
    Electronic Resource
    Renal clearance of digoxin in man after sodium loading or furosemide treatment (1983)
    Springer
    European journal of clinical pharmacology 25 (1983), S. 375-379 
    Details
    ISSN: 1432-1041
    Keywords: digoxin ; renal clearance ; natriuresis ; sodium loading ; sodium depletion ; furosemide ; diuretic effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To evaluate the influence of different types of natriuresis on the renal clearance of digoxin (Cldig) and the Cldig/Clcr ratio, studies were performed in which sodium-depleted patients were placed on a moderately high sodium diet for 6 days. In another group natriuresis was evoked by furosemide. In the first study, in 10 patients, there was a 10-fold increase in Na excretion and a small rise in diuresis (V) and Clcr, which was accompanied by an increase in Cldig from 57.5±32, and 60.7±27.3 (duplicate measurements) to 103.9±55.4 (p〈0.01) and 103.8±46.5 ml min−1 (p〈0.01). Cldig/Clcr rose from 0.60±0.24 and 0.61±0.16 to 0.91±0.31 and 0.91±0.21, respectively (bothp〈0.005). Serum digoxin concentration declined from 1.24±0.35 and 1.19±0.40 to 1.02±0.35 and 0.97±0.32 µg/l (bothp〈0.01) during the high sodium diet. In the furosemide — induced natriuresis (6 patients), changes in Na excretion and V were a multiple of those caused by Na loading, but the Cldig/Clcr ratio was not increased. The results are in accordance with the concept of digoxin backdiffusion in the proximal tubules, which is dependent on proximal Na reabsorption. In the more distal segments of the nephron, where the action of furosemide occurs, there does not appear to be any transtubular movement of digoxin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01037951
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  • 2
    Electronic Resource
    Electronic Resource
    Temperature, light, and photoperiod responses of some Northeast American and West European endemic rhodophytes in relation to their geographic distribution (1984)
    Springer
    Helgoland marine research 38 (1984), S. 273-304 
    Details
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between distributional boundaries and temperature responses of some Northeast American and West European endemic and amphiatlantic rhodophytes was experimentally determined under varying regimes of temperature, light, and daylength. Potentially critical temperatures, derived from open ocean surface summer and winter isotherms, were inferred from distributional data for each of these algae. On the basis of the distributional data the algae fall within the limits of three phytogeographic groups: (1) the Northeast American tropical-to-temperate group; (2) the warm-temperate Mediterranean Atlantic group; and (3) the amphiatlantic tropical-to-warm temperate group. Experimental evidence suggests that the species belonging to the northeast American tropical-to-temperate group(Grinnellia americana, Lomentaria baileyana, andAgardhiella subulata) have their northern boundaries determined by a minimum summer temperature high enough for sufficient growth and/or reproduction. The possible restriction of 2 species (G. americana andL. baileyana) to the tropical margins may be caused by summer lethal temperatures (between 30 and 35 °C) or because the gradual disintegration of the upright thalli at high temperatures (〉30 °C) promotes an ephemeral existence of these algae towards their southern boundaries. Each of the species have a rapid growth and reproductive potential between 15–30 °C with a broad optimum between 20–30 °C. The lower limit of survival of each species was at least 0 °C (tested in short days only). Growth and reproduction data imply that the restrictive distribution of these algae to the Americas may be due to the fact that for adequate growth and/or reproduction water temperatures must exceed 20 °C. At temperatures ≦15 °C reproduction and growth are limited, and the amphiatlantic distribution through Iceland would not be permitted. On the basis of experimental evidence, the species belonging to the warm-temperate Mediterranean Atlantic group(Halurus equisetifolius), Callophyllis laciniata, andHypoglossum woodwardii), have their northern boundaries determined by winter lethal temperatures. Growth ofH. equisetifolius proceeded from 10–25 °C, that ofC. laciniata andH. woodwardii from 5–25 °C, in each case with a narrow range for optimal growth at ca. 15 °C. Tetrasporelings ofH. woodwardii showed limited survival at 0 °C for up to 4 d. For all members of the group tetrasporangia occurred from 10–20 °C. The southern boundary ofH. equisetifolius andC. laciniata is a summer lethal temperature whereas that ofH. woodwardii possibly is a winter growth and reproduction limit. Since each member of this group has a rather narrow growth and survival potential at temperatures 〈5 °C and 〉20 °C, their occurrence in northeast America is unlikely. The (irregular) distribution ofSolieria tenera (amphiatlantic tropical-to-warm temperate) cannot be entirely explained by the experimental data (possibly as a result of taxonomic uncertainties).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01997485
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  • 3
    Electronic Resource
    Electronic Resource
    Temperature responses of some North AtlanticCladophora species (Chlorophyceae) in relation to their geographic distribution (1984)
    Springer
    Helgoland marine research 38 (1984), S. 349-363 
    Details
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The temperature responses for growth and survival have been experimentally tested for 6 species of the green algal genusCladophora (Chlorophyceae; Cladophorales) (all isolated from Roscoff, Brittany, France, one also from Connecticut, USA), selected from 4 distribution groups, in order to determine which phase in the annual temperature regime might prevent the spread of a species beyond its present latitudinal range on the N. Atlantic coasts. For five species geographic limits could be specifically defined as due to a growth limit in the growing season or to a lethal limit in the adverse season. These species were: (1)C. coelothrix (Amphiatlantic tropical to warm temperate), with a northern boundary on the European coasts formed by a summer growth limit near the 12°C August isotherm. On the American coasts sea temperatures should allow its occurrence further north. (2)C. vagabunda (Amphiatlantic tropical to temperate), with a northern boundary formed by a summer growth limit near the 15°C August isotherm on both sides of the Atlantic. (3)C. dalmatica, as forC. vagabunda. (4)C. hutchinsiae (Mediterranean-Atlantic warm temperate), with a northern boundary formed by a summer growth limit near the 12°C August isotherm, and possibly also a winter lethal limit near the 6°C February isotherm; and a southern boundary formed by a southern lethal limit near the 26°C August isotherm. It is absent from the warm temperate American coast because its lethal limits, 5° and 30°C, are regularly reached there. (5) Preliminary data forC. rupestris (Amphiatlantic temperate), suggest the southeastern boundary on the African coast to be a summer lethal limit near the 26°C August isotherm; the southwestern boundary on the American coast lies on the 20°C August isotherm. For one species,C. albida, the experimental growth and survival range was wider than expected from its geographic distribution, and reasons to account for this are suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02027686
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  • 4
    Electronic Resource
    Electronic Resource
    Phytogeographic distribution groups of benthic marine algae in the North Atlantic Ocean. A review of experimental evidence from life history studies (1982)
    Springer
    Helgoland marine research 35 (1982), S. 153-214 
    Details
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experimentally determined lethal temperatures and temperatures limiting growth or reproduction in the life histories of 15 benthic algal species were used to infer possible phytogeographic boundaries in the North Atlantic Ocean. These appeared to correspond closely with phytogeographic boundaries based on distribution data. Many boundaries appeared to be of a composite nature. For instance, the southern boundary ofNemalion helminthoides is interpreted as a “southern reproduction boundary” on the N. Atlantic E. shore and a “southern lethal boundary” on the N. Atlantic W. shore. The northern boundary on both sides of the ocean is a “northern reproduction boundary”.N. helminthoides is a typical representative of the “amphiatlantic temperate distribution group”, to which seven other of the fifteen investigated species belong (Chondrus crispus, Desmarestia aculeata, D. viridis, Monostroma grevillei, Acrosiphonia “arcta” with a comparable composite southern boundary;Rhodochorton purpureum with a “southern lethal boundary”).Polysiphonia ferulacea andDictyota dichotoma are treated as representatives of the “amphiatlantic tropical-to-warm-temperate distribution group”, andP. denudata as representative of the “amphiatlantic tropical-to-temperate group”.P. harveyi belongs to the N.E. American temperate group and is bounded by a “northern reproduction boundary” and a “southern reproduction boundary”. This is one of the very few species endemic to N.E. America. This poor endemism is ascribed to the vast adverse sediment shores and their additional acting as barriers to glacial northsouth displacements of the flora; it is not related to the wide annual temperature fluctuations (〉20 °C) typical for N.E. America. The temperate algal flora of Japan, however, which is extremely rich in endemic species is subject to equally wide annual temperature fluctuations.Bonnemaisonia hamifera is such a Japanese endemic, which has been accidentally introduced into the North Atlantic Ocean where its life history seems to be disrupted: it is maintained mainly by vegetative propagation of the heteromorphic tetrasporophyte. The species of the “warm temperate Mediterranean-Atlantic group” are probably too stenothermous for life on N.E. American shores; they need annual temperature fluctuations〈20 °C.Acrosymphyton purpuriferum seems to belong to this group, but arguments are presented to unite this species withA. caribaeum and to range it under the “amphiatlantic tropical-to-warm-temperate group”.Clathromorphum circumscriptum belongs to the “Arctic distribution group” and has a “southern reproduction boundary” across the ocean along the 3 °C February isotherm. This species is able to survive temperatures of about 20 °C. Five amphiequatorial temperate species discussed in this paper and four in another related paper have similar maximum winter temperatures of 14–17 °C (mean monthly values) allowing reproduction. Their amphiequatorial distribution can be explained by assuming similar low temperatures in the euphotic zone along E. Pacific and E. Atlantic equatorial coasts i.e. in narrow inshore belts of intensified upwelling during the presumably intensified glacial circulation of the ocean gyres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01997551
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  • 5
    Electronic Resource
    Electronic Resource
    World-wide latitudinal and longitudinal seaweed distribution patterns and their possible causes, as illustrated by the distribution of Rhodophytan genera (1984)
    Springer
    Helgoland marine research 38 (1984), S. 227-257 
    Details
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The degree of similarity between red algal generic floras in each pair of 22 climatically defined biogeographic regions was established on a world-wide scale by Jaccard's similarity index and by an hierarchical clustering with an agglomerative centroid method. Two clusterings were carried out, the first one on the basis of all 637 genera, and the second one on the basis of genera not occurring in the tropics and non-endemic to any one of the 22 regioms (145 genera). This latter clustering served to detect better the relationships among non-tropical floras. The results indicate the following division of the earth's rhodophytan seaweed floras: (1) A rich tropical-warm temperate "Tethyan" group including the rich tropical Indo W Pacific and W Atlantic floras, and the rich warm temperate NW Pacific and NE Atlantic floras; (2) the depauperate extensions of the above group (the tropical E Pacific and E Atlantic floras, and the warm temperate NW and SW Atlantic floras); (3) a cold temperate and a warm temperate N Pacific group; (4) an Arctic-cold temperate N Atlantic group and a NE Atlantic warm temperate flora; (5) an Antarctic-cold temperate southern hemisphere group including the cold temperate SE Pacific, SW Atlantic, SE Atlantic floras, and the Antarctic flora; (6) the two highly individual, but slightly related warm temperate SE Atlantic flora (S. Africa) and SW Pacific flora (Southern Australia and Northern New Zealand); (7) the depauperate warm temperate SE Pacific flora. Although the northern and southern hemisphere temperate and polar floras are quite unrelated (on the basis of genera lacking in the tropics), they share nonetheless a number of cool water genera which apparently have succeeded in passing the adverse tropical belt. The rich tropical-warm temperate group is thought to consist of vicariant portions of a formerly continuous Tethyan flora. The N Pacific and N Atlantic temperate floras are thought to have developed independently since the Oligocene (~ 40.106 y) deterioration of the climate and to have partially mixed their cool water genera only after the Pliocene inundation (2.106 y) of the Bering Land Bridge. The warm-temperate floras of S Africa and southern Australia probably owe their richness and individuality to a very long isolation (already at the start of the Cenozoicum) and a continued residence in warm temperate conditions with small seasonal fluctuations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01997483
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  • 6
    Electronic Resource
    Electronic Resource
    Foreword (1984)
    Springer
    Helgoland marine research 38 (1984), S. 225-225 
    Details
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01997482
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  • 7
    Electronic Resource
    Electronic Resource
    Search for possible latitudinal ecotypes inDumontia contorta (Rhodophyta) (1984)
    Springer
    Helgoland marine research 38 (1984), S. 389-399 
    Details
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of daylength and temperature on the formation of erect fronds (macrothalli) from crusts (microthalli) ofDumontia contorta (S. G. Gmel.) Rupr. from three localities in Nova Scotia and one locality in Southern Iceland were investigated and compared to such effects shown by strains from three different East Atlantic localities (Isle of Man; Zeeland, S. W. Netherlands; and Roscoff, Brittany, France). Although these strains showed small differences in their temperature-daylength responses, these could not be interpreted as latitudinal adaptations, and consequently no latitudinal ecotypes could be found forDumontia contorta in the N. Atlantic Ocean. Upright fronds are formed at a broad temperature range of about 4°–18°C and at daylengths ≤ 13 h. Only in the southernmost part of its distribution area can high autumnal temperatures be expected to block the reappearance of upright fronds after passage of the critical daylength in September. In the larger part of the distribution area even summer temperatures are not high enough to block formation of uprights and here apparently only short daylengths initiate the reappearance of young upright fronds in autumn. The consequences of these aspects of the life history regulation for the geographic distribution are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02027688
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