| 11. |
- Ahrén, C M, et al.
(författare)
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Comparison of methods for detection of colonization factor antigens on enterotoxigenic Escherichia coli.
- 1986
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 23:3, s. 586-91
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Tidskriftsartikel (refereegranskat)abstract
- Fecal Escherichia coli isolates from 196 patients with watery diarrhea and 68 healthy individuals (controls) were analyzed in Bangladesh immediately after isolation for the presence of colonization factor antigen (CFA) I or II (CFA/I or CFA/II, respectively) by a mannose-resistant hemagglutination (MRHA) test with six species of erythrocytes and by a slide agglutination test with absorbed CFA/I or CFA/II antisera. The presence of CFAs was confirmed by immunodiffusion analyses done in Sweden. By these methods, it was found that 49 of 69 enterotoxin-producing E. coli strains isolated from patients carried CFA/I or CFA/II, whereas none of the nonenterotoxigenic E. coli isolates or the three toxin-positive strains isolated from healthy individuals carried these adhesins. All E. coli strains retained their MRHA ability after transportation to Sweden followed by one subculture and after storage at -70 degrees C (but not at room temperature) for 1 to 2 years without further subculturing. After 5 to 10 subcultures of the fresh isolates, however, 70% of the initially CFA/I- and 80% of the initially CFA/II-carrying strains analyzed did not hemagglutinate. The efficacy of different methods for detecting CFAs on the fresh isolates was compared with that of immunodiffusion. The sensitivity of MRHA with human blood group A erythrocytes for the detection of CFA/I was high (97%), but the specificity was only 69%. The sensitivity of MRHA with bovine erythrocytes for the detection of CFA/II in Bangladesh was very low but increased considerably when chicken erythrocytes were also used. Whereas both false-positive and false-negative reactions were obtained when absorbed CFA antisera were used for agglutination, antisera against purified CFAs were equally effective as immunodiffusion in identifying CFA/I and CFA/II-carrying strains.
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| 12. |
- Alafuzoff, Irina, 1952-
(författare)
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Histopathological and immunocytochemical studies in age-associated dementias : the importance of rigorous histopathological criteria for classification of progressive dementia disorders
- 1985
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dementia is an age-associated organic brain disorder, recognizable by the essential features of psychological or behavioral abnormality associated with permanent dysfunction of the brain interfering with social and occupational functioning.There are two clinical and three histopathological forms of dementia 1) primary degenerative dementia, (PDD), or Alzheimer's dementia/Senile dementia of Alzheimers type (AD/SDAT) which is associated with clinical features of uniform progression and insidious onset of symptoms and histopathologically i- dentified by the occurrence of neurofibrillary tangles (NFT) and senile/neuritic plaques (SP/NP) in various cortical and subcor- tical regions; 2) vascular dementia, or multi-infarct dementia (MID), which is associated with clinical features of stepwise progress and patchy distribution of deficits, and histopathologically identified by the occurrence of multiple large and/or small haemorrhagic and/or ischaemic infarcts in various cortical and subcortical regions and 3) intermediate form of dementia or "mixed” ("combined") dementia (AD-MID), which is histopatho- logically associated with the coexistance of symptoms and lesions observed in AD/SDAT and MID, and clinically referred to the MID group. The DSM-III criteria separate the demented into two groups, AD/SDAT and MID, while there are no unique clinical criteria for the AD-MID patients. The clinical diagnosis of dementia according to the DSM-III criteria was shown to be insufficient . Histopathological diagnostic criteria were postulated by us for 1) pathological changes developing in mentallyunimpaired ageing, 2) AD/ SPAT, 3) MID and 4) AD-MID.These histopathological classes could be separated, by means of multivariate data analysis. The pathology in AD-MID was shown not to be merely a linear combination of the AD/SDATand MID pathology.Intrathecal synthesis of Ig, oligoclonal bands or other abnormal proteins in the CSF could not be demonstrated in aged non-demen- ted and demented patients.The blood-cerebrospinal barrier (B-CSF-B) or blood-brain barrier (BBB) function alters with age and this alteration was shown to be more pronounced in MID and AD-MID patients. In MID and AD-MID patients the BBB alteration involves primarily the grey matter while in AD/SDAT patients the alteration would appear to involve only the white matter. The BBB dysfunction and a possible complement activation, either through antibody-anti- gen activation or other complement activators, was visualized in MID and AD-MID patients as perivascular serum protein deposits in the grey matter, always with a capillary in the center. The occurrence of some serum proteins in plaques, and the previously descibed localization of plaques in close relationship to the capillaries, suggest that altered BBB function and serum factors may be involved in the etiology and maturation of plaques while the etiology and maturation of tangles may not be directly dependent on these factors, as they were never labelled with any of the antisera studied.
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| 13. |
- Alafuzoff, I, et al.
(författare)
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Histopathological criteria for progressive dementia disorders : clinical-pathological correlation and classification by multivariate data analysis.
- 1987
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Ingår i: Acta Neuropathologica. - 0001-6322 .- 1432-0533. ; 74:3, s. 209-25
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Tidskriftsartikel (refereegranskat)abstract
- Autopsied brains from 55 patients with dementia between 59-95 years of age (mean age 77.9 +/- 8.1 years) and 19 non-demented individuals between 46-91 years of age (mean age 74.3 +/- 10.5 years) were examined to establish histopathological criteria for normal ageing, primary degenerative [Alzheimer's disease (AD)/senile dementia of Alzheimer type (SDAT)] and vascular (multi-infarct) dementia (MID) disorders. Senile/neuritic plaques, neurofibrillary tangles, microscopic infarcts and perivascular serum protein deposits were quantified in the frontal lobe (Brodmann area 10) and in the hippocampus. The demented patients were classified according to the DSM-III criteria into AD/SDAT and MID. Operationally defined histopathological criteria for dementias, based on the degree/amount of the histopathological changes seen in aged non-demented patients, were postulated. The demented patients were clearly separable into three histopathological types, namely AD/SDAT, MID and AD-MID, the dementia type where both the degenerative and the vascular changes are coexistent in greater extent than are seen in the non-demented individuals. Using general clinical, gross neuroanatomical and histopathological data three separate dementia classes, namely AD/SDAT, MID and AD-MID, were visualized in two-dimensional space by multivariate data analysis. This analysis revealed that the pathology in the AD-MID patients was not merely a linear combination of the pathology in AD/SDAT and MID, indicating that AD-MID might represent a dementia type of its own. The clinical diagnosis for AD/SDAT and MID was certain in only half of the AD/SDAT and one third of the MID cases when evaluated histopathologically and by multivariate data analysis. AD/SDAT, MID and AD-MID were histopathologically diagnosed in 49%, 24% and 27%, respectively, of all the dementia cases studied. Opposite correlation between the number of tangles, plaques and the patient age in non-demented and AD/SDAT cases were observed, indicating that the pathogenesis of tangles and plaques in the two groups of patients might be different and that AD/SDAT might not be a form of an exaggerated ageing process.
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| 14. |
- Albiin, Nils, 1955-
(författare)
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Middle ear structure in relation to function : the rat in middle ear research
- 1985
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present study was undertaken to evaluate the rat as a model for middle ear research. The rat was chosen primarily because the gross structure of its middle ear shows several similarities to that of man. It was considered of great importance to make a thorough structural study of the rat middle ear and to compare the results with those reported for the human middle ear. The thesis therefore includes independent studies on various aspects of rat middle ear structure and function as well as a review of the literature. The most pertinent findings in the experimental part of this study were the following.The rat Eustachian tube consists of a nasopharyngeal, and a cartilaginous and bony portion. The orifice of the nasopharyngeal portion is composed of two soft tissue lips, which appear to be opened mainly by the action of the salpingopharyngeal muscle, but also by the levator and tensor veli palatini muscles. The cartilaginous portion appears to be opened solely by the tensor veli palatini muscle. The tensor tympani muscle seems to have no effect on the tube.A ciliated and secretory epithelium lines the inferomedial walls of the tube throughout its length. In the tympanic cavity these thelial cell types extend as two tracts - one anterior and the other inferoposterior to the promontory - which communicate with the epitympanic/attic compartments. The remaining parts of the tube and the tympanic cavity are covered by a squamous/cuboidal, non-ciliated epithelium. The subepithelial loose connective tissue contains vessels, nerves, and connective tissue cells, among these mast cells. The mast cells are confined to areas covered by the ciliated epithelium, and in the floor of the bulla, in the pars flaccida, and along the manubrial vessels. Glands are restricted to the Eustachian tube.In the clearance/transport of serum-like material, from the epitympanum towards the tube, hydrostatic forces appear to be important.The tympanic membrane is vascularized from meatal and tympanal vessels. Meatal vessels branch in the pars flaccida and along the handle of the malleus, where they are localized directly beneath the outer, keratinizing, stratified, squamous epithelium. Furthermore, meatal vessels form a vascular network at the junction between the fibrocartilaginous annulus and the tympanic sulcus. Tympanal vessels send branches to the periphery of the pars tensa, where they run immediately beneath the tympanal, simple, squamous epithelium. In the major portion of the pars tensa, no blood vessels were found.The rat stapedial artery is a thin-walled vessel with a wide lumen. Without branching, it runs through the tympanic cavity to the extratympanal regions it supplies. In contrast to the corresponding artery in man, the rat stapedial artery persists throughout life. The artery does not seem to be affected by the fluid produced during experimentally induced otitis media with effusion.The middle ear structure in the rat and in man show both similarities and differences. If the differences are kept in mind and considered, it would seem that the rat is indeed a suitable model for experimental middle ear research.
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| 15. |
- Allard, Per, et al.
(författare)
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Age-correlated loss of dopamine uptake sites labeled with [3H]GBR-12935 in human putamen.
- 1989
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Ingår i: Neurobiology of Aging. - 0197-4580 .- 1558-1497. ; 10:6, s. 661-4
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Tidskriftsartikel (refereegranskat)abstract
- The effects of age (19-100 years) upon dopamine uptake sites labeled with [3H]GBR-12935 in human postmortem putamen from 20 individuals were studied. There was a 70% decrease in binding density (Bmax) over the adult age range. No significant changes in binding affinity (Kd) were detected, the mean Kd being 1.0 +/- 0.2 nM (mean +/- S.E.M.). Nor were there any changes in binding related to the postmortem delay. Based on the findings that [3H]GBR-12935 labels the uptake site for dopamine, it is suggested that the age-related loss of [3H]GBR-12935 binding in human putamen reflects a degeneration of dopamine neurites.
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| 16. |
- Allergren, Björn, et al.
(författare)
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Studiehandbok
- 1981
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 17. |
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| 18. |
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| 19. |
- Alm, Håkan, 1948-
(författare)
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Learning of probabilistic inference tasks : effects of uncertainty and function form
- 1982
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is concerned with the problem of how people learn to use uncertain information for making judgments. The general framework for the thesis is Social Judgment Theory (SJT). First the S3T paradigm, and some research conducted within the paradigm, is briefly described, and a series of four empirical studies is summarized. The studies are concerned with two factors that have been found to have great effect on subjects achievement in cue probability learning (CPL) tasks: task predictability, and the form of the function relating cue and criterion. The effects of these two factors were studied in experiments employing cue-probability learning tasks. The studies concerned with task predictability addressed the following questions (a) Do subjects understand the probabilistic nature of CPL-tasks? (b) Are subjects able to detect that a random task is, in fact, random, a study undertaken to test an aspect of Seligmans "theory of helplessness". This was also an attempt to bring emotional factors more in foeus.(c) Do subjects use data from the task only to test hypotheses, or do they use data also to construct hypotheses?The results showed that (a) subjects do not seem to be able to cope with probabilistic tasks in an optimal statistical manner. Instead they seem to use a deterministic approach to the tasks, because they do not understand the probabilistic nature of the task, (b) Task predictability affecs subjects mood, but not in the way predicted by Seligman, (c) Subjects seem to use data frorn the task only to test their hypotheses. The results thus supported the hypotheses sampling model for the learning of CPL-tasks.As for the factor of function form, the following questions were addressed, (a) What hypotheses about relations between variables do subjects have? (b) Is the difficulties subjects have in learning complex rules in CPL-tasks due to a low availability of hypotheses about complex rules? The results showed that, (a) the hypothesis hierarchy as revealed in the present experiments was in general agreement with earlier results. However, few nonlinear hypotheses were observed, and other rules than functional rules were observed, (b) The difficulties subjects have to learn complex rules in CPL-tasks do not seem to be caused by low availability of rules.Finally, some suggestions are given for how the SJT-paradigm should be developed. Specifically, it is suggested that the effects of emotional factors should be given more attention, and that the paradigm should be turned into a more general hypothesis testing model
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| 20. |
- Anderson, Bo, 1931-, et al.
(författare)
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Om sociala näverk och hälsa
- 1989
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Ingår i: Socialmedicinsk Tidskrift. - Stockholm. - 0037-833X. ; :5-6, s. 223-229
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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