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- Agardh, Carl-David, et al.
(författare)
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Hypoglycemic brain injury. I. Metabolic and light microscopic findings in rat cerebral cortex during profound insulin-induced hypoglycemia and in the recovery period following glucose administration
- 1980
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Ingår i: Acta Neuropathologica. - 1432-0533. ; 50:1, s. 31-41
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Tidskriftsartikel (refereegranskat)abstract
- Profound hypoglycemia causing the disappearance of spontaneous EEG activity was induced by insulin in rats. For analysis of cerebral cortical concentrations of labile phosphates, glycolytic metabolites and amino acids, the brain was frozen in situ. For microscopic analysis of the corresponding cerebral cortical areas the brain was fixed by perfusion. Hypoglycemia with an isoelectric EEG for 30 and 60 min caused severe perturbation of the cerebral energy metabolites. After both 30 and 60 min of isoelectric EEG, two microscopically different types of nerve cell injury were seen. Type I injury was characterized by angulated, darkly stained neurons with perineuronal vacuolation, mainly affecting small neurons in cortical layer 3. Type II injured neurons, mainly larger ones in layers 5–6, were slightly swollen with vacuolation or clearing (depending on the histotechnique used) of the peripheral cytoplasm, but had no nuclear changes. Recovery was induced by glucose injection. Improvement in the cerebral energy state occurred during the 30 min recovery period even after 60 min of hypoglycemia. However, the persisting reduction in the size of adenine nucleotide and amino acid pools after 30 or 180 min recovery suggested that some cells remained damaged. In confirmation many type I injured neurons persisted during the recovery suggesting an irreversible injury. The disappearance of virtually all type II injuries indicated reversibility of these histopathological changes. The microscopic changes in hypoglycemia were different from those in anoxia-ischemia suggesting a dissimilar pathogenesis in these states despite the common final pathway of energy failure.
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| 2. |
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| 3. |
- Alm, P., et al.
(författare)
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Immunoglobulin-A producing probably primary lymphoma of the breast
- 1983
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Ingår i: Virchows Archiv. - 1432-2307. ; 399:3, s. 355-360
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Tidskriftsartikel (refereegranskat)abstract
- A breast tumour from a 65-year old woman was found to be a primary non-Hodgkin lymphoma, a very rare primary malignancy in this location. The lymphoma was of a diffuse histiocytic type according to the classification of Rappaport, or polymorphic immunocytoma according to the Kiel classification. Immunohistochemistry, not previously reported for breast lymphomas, revealed the production of IgA. In the serum this appeared as an IgA M-component which was greatly reduced after tumour removal. Immunological properties of primary breast lymphomas are reviewed, we suggest further extended studies with the immunohistochemical use of marker substances for the evaluation of prognosis. © 1983 Springer-Verlag.
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| 4. |
- Aronsson, Gunnar
(författare)
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On certain singular solutions of the partial differential equation ux2uxx+2uxuyuxy+uy2uyy=0
- 1984
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Ingår i: Manuscripta mathematica. - 0025-2611 .- 1432-1785. ; 47:1-3, s. 133-151
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Tidskriftsartikel (refereegranskat)abstract
- The partial differential equation treated here is the formal limit of the p-harmonic equation in R2, for p →∞. Questions related to the smoothness of solutions and the possible existence of stationary points are central for the theory. The singular solutions constructed here bring new light on these questions.
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| 5. |
- Bengtsson, Hans, et al.
(författare)
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Parental feeding rate in relation to begging behavior in asynchronously hatched broods of the great tit Parus major: An experimental study.
- 1983
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Ingår i: Behavioral Ecology and Sociobiology. - 1432-0762. ; 12:3, s. 243-251
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Tidskriftsartikel (refereegranskat)abstract
- Four experiments manipulated the stimulus situation encountered by great tits on their feeding visits to the brood in order to explore its effect on feeding rate. Three broods containing 8, 8, and 10 nestlings were studied. A higher feeding rate was observed under the following conditions: (1) after a period of food deprivation, as compared with normal conditions and satiation through artifical feeding; (2) in periods when recorded begging calls were played during feeding visits, as compared with control periods; and (3) after temporary removal from the nest of heavier, as compared with lighter, siblings. The lighter nestlings benefitted more (in terms of weight gain) from the increase in parental feeding rate following the playing of begging calls than did the heavier nestlings. Differences in weight within broods did not affect the amount of food the parents brought. It is concluded that parental feeding rate is affected not simply by the begging of the hungriest nestling but rather by the behavior of all the nestlings, which makes possible an adjustment of the feeding rate to the average hunger level of the brood.
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| 6. |
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| 7. |
- Berglund, Anders, et al.
(författare)
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Biotic and abiotic factors determining the distribution of two prawn species: Palaemon adspersus and P. squilla
- 1981
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Ingår i: Oecologia. - 0029-8549 .- 1432-1939. ; 49:3, s. 300-304
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Tidskriftsartikel (refereegranskat)abstract
- The reasons behind the absence of the prawn Palaemon adspersus and the presence of P. squilla in rockpools and on bare sand bottoms were studied. Some maximal abundances in different habitats are given. Introduction experiments into natural and artificial rockpools and measurements of tolerance towards low oxygen levels showed that nocturnal hypoxia excluded P. adspersus which was significantly more sensitive to oxygen depletion. Respiration rates measured by the closed-bottle method showed no interspecific difference. On bare sand bottoms P. aspersus was probably excluded by predators, since predator exclusion experiments in cages and predator inclusion experiments in containers showed that P. adaspersus was more vulnerable to predation than P. squilla.The costs for being able to cope with a wide array of habitat in P. squilla are probably balanced by the benefits of access to habitats such as intertidal rockpools, very shallow bottoms and deeper sand bottoms. Tolerance towards abiotic factors extends its habitat range upwards into shallower waters, and tolerance towards biotic factors, i.e. predation, extends it downwards.
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| 8. |
- Berglund, Anders
(författare)
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Coexistence, size overlap and population regulation in tidal vs non-tidal Palaemon prawns
- 1982
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Ingår i: Oecologia. - 0029-8549 .- 1432-1939. ; 54:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The effect of increased habitat heterogeneity in tidal areas on coexistence between Palaemon prawns was studied at eight sites along the European Atlantic coast. Two species which are sympatric in non-tidal areas, Palaemon adspersus Rathke and P. squilla (L.) are largely allopatric in tidal areas, and the sympatric size difference decreases in allopatry. In tidal areas the smaller species, P. squilla, is restricted to brown algal belts and rockpools. A third species, P. serratus (Pennant), larger than the others, occurs under oceanic salinities in subtidal brown algal belts and there has forced P. squilla to restrict its habitat distribution to adjacent intertidal rockpools. At estuarine salinities, however, P. squilla also inhabits the brown algal belts. A larger diel variation in stomach fullness index in P. squilla than in P. adspersus persists in non-tidal areas. Abiotic factors probably restrict the two largest species, viz. P. adspersus and P. serratus, to subtidal environments; these species are sensitive to the extremes in salinity, temperature or O2 levels characteristic of the intertidal zone. Competition and/or predation probably relegates P. squilla to the intertidal zone. In non-tidal areas, where this zone is reduced, P. squilla increases its niche width and coexists with P. adspersus, and the size differentiation associated with sympatry may reduce interspecific competition.
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| 9. |
- Berglund, Anders, et al.
(författare)
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Genetic differentiation in populations of two Palaemon prawn species at the Atlantic east coast : does gene flow prevent local adaptation?
- 1983
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Ingår i: Marine Biology. - 0025-3162 .- 1432-1793. ; 77:1, s. 49-57
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Tidskriftsartikel (refereegranskat)abstract
- Two Palaemon prawn species, P. adspersus Rathke and P. squilla (L.), occur along the European Atlantic coast. In areas heavily affected by tides (Netherlands and France), one species, P. squilla, inhabits the intertidal zone, and P. adspersus is found subtidally in the Zostera marina meadows. In areas with small tidal ranges (Sweden) both species occur in the Z. marina zone, and here the body size of P. squilla is reduced, something that in turn reduces reproductive output in this species. Is adaptive improvement in non-tidal P. squilla populations prevented by too extensive gene flow from tidal areas? To wanswer this, genetic differentiation was studied by horizontal starch gel electrophoresis. Each of the two species was sampled at five sites along the European Atlantic coast. Twenty-two enzymes representing 25 loci were scored. Significant genetic heterogeneity between sites was found in both species. Thus the extensive gene flow hypothesis was not supported by the results, and non-tidal populations ought to have the possibility to adapt to local conditions.
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| 10. |
- Berglund, S., et al.
(författare)
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Arsenopyrite and sphalerite as T-P indicators in sulfide ores from northern Sweden
- 1980
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Ingår i: Mineralium Deposita. - 0026-4598 .- 1432-1866. ; 15:2, s. 175-187
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Tidskriftsartikel (refereegranskat)abstract
- The compositions of arsenopyrite and sphalerite from five Swedish metamorphosed Cu, Zn-sulfide deposits are related to T and P, according to the methods described by Kretschmar and Scott (1976) and Scott (1973). The As/S ratio of arsenopyrite indicates an equilibrium temperature around 400°C for all the deposits studied, whereas the sphalerite barometer shows pressures between 5 and 7 kb. The mineral assemblages of the bedrocks indicate a similar temperature but a lower pressure. A constant fs2 is probably only effective over distances of millimetres or a few centimetres in the samples studied. The fs2 has always been lower in the surrounding rocks than in the ores as indicated by a higher As/S in arsenopyrite, more FeS in sphalerites and the absence of pyrite.
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