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- Arvidsson, Ann-Kristin, et al.
(author)
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Tyr-716 in the platelet-derived growth factor beta-receptor kinase insertis involved in GRB2 binding and Ras activation
- 1994
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In: Molecular and Cellular Biology. - : American Society for Microbiology. - 0270-7306 .- 1098-5549. ; 14:10, s. 6715-6726
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Journal article (peer-reviewed)abstract
- Ligand stimulation of the platelet-derived growth factor (PDGF) beta-receptor leads to activation of its intrinsic tyrosine kinase and autophosphorylation of the intracellular part of the receptor. The autophosphorylated tyrosine residues mediate interactions with downstream signal transduction molecules and thereby initiate different signalling pathways. A pathway leading to activation of the GTP-binding protein Ras involves the adaptor molecule GRB2. Here we show that Tyr-716, a novel autophosphorylation site in the PDGF beta-receptor kinase insert, mediates direct binding of GRB2 in vitro and in vivo. In a panel of mutant PDGF beta-receptors, in which Tyr-716 and the previously known autophosphorylation sites were individually mutated, only PDGFR beta Y716F failed to bind GRB2. Furthermore, a synthetic phosphorylated peptide containing Tyr-716 bound GRB2, and this peptide specifically interrupted the interaction between GRB2 and the wild-type receptor. In addition, the Y716(P) peptide significantly decreased the amount of GTP bound to Ras in response to PDGF in permeabilized fibroblasts as well as in porcine aortic endothelial cells expressing transfected PDGF beta-receptors. The mutant PDGFR beta Y716F still mediated activation of mitogen-activated protein kinases and an increased DNA synthesis in response to PDGF, indicating that multiple signal transduction pathways transduce mitogenic signals from the activated PDGF beta-receptor.
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| 3. |
- Arkhammar, P., et al.
(author)
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Protein kinase C modulates the insulin secretory process by maintaining a proper function of the beta-cell voltage-activated Ca2+ channels
- 1994
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In: Journal of Biological Chemistry. - : Baishideng Publishers. - 0021-9258 .- 1083-351X. ; 269:4, s. 2743-2749
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Journal article (peer-reviewed)abstract
- In the present study an attempt was made to further elucidate the molecular mechanisms whereby protein kinase C (PKC) modulates the beta-cell stimulus-secretion coupling. Regulation of Ca2+ channel activity, [Ca2+]i, and insulin release were investigated in both normal pancreatic mouse beta-cells and in similar beta-cells deprived of PKC activity. [Ca2+]i was measured with the intracellular fluorescent Ca2+ indicator fura-2 and the Ca2+ channel activity was estimated by the whole cell configuration of the patch-clamp technique. To reveal the various isoenzymes of PKC present in the mouse beta-cell, proteins were separated by one-dimensional gel electrophoresis and Western blotting was performed. The production of inositol phosphates was measured by ion-exchange chromatography and insulin release was measured radioimmunologically. Acute stimulation with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate resulted in suppression of both the carbamylcholine-induced increase in [Ca2+]i and production of inositol 1,4,5-trisphosphate. Under these conditions the increase in [Ca2+]i in response to glucose was similar to that found in control cells. When beta-cells were deprived of PKC, by exposure to 200 nM 12-O-tetradecanoylphorbol-13-acetate for 24-48 h, there was an enhanced response to carbamylcholine. This response constituted increases in both the [Ca2+]i signal and production of inositol 1,4,5-trisphosphate. Interestingly, cells with down-regulated PKC activity responded more slowly to glucose stimulation, when comparing the initial increase in [Ca2+]i, than control cells. On the other hand, the maximal increase in [Ca2+]i was similar whether or not PKC was present. Moreover, PKC down-regulated cells exhibited a significant reduction of maximal whole cell Ca2+ currents, a finding that may explain the altered kinetics with regard to the [Ca2+]i increase in response to the sugar. Both the alpha and beta 1 forms of the PKC isoenzymes were present in the mouse beta-cell and were also subjected to PKC down-regulation. Hence, either of these isoenzymes or both may be involved in the modulation of phospholipase C and Ca2+ channel activity. Since insulin release under physiological conditions is critically dependent on Ca(2+)-influx through the voltage-gated L-type Ca2+ channels, the kinetics of hormone release was expected to demonstrate a similar delay as that of the [Ca2+]i increase. Although not as pronounced, such a delay was indeed also observed in the onset of insulin release. There was, however, no effect on the total amounts of hormone released. There was,h owever, no effect on thet otal amounts of hormone released. The present study con- firms that PKC has multiple roles and thereby interacta at different sites in the complex series of events consti- tuting the #?-cell signal-transduction pathway. It is sug- gested that PKC may be tonically active and effective in the maintenance of the phosphorylation state of the voltage-gated L-type Ca2+ channel, enabling an appro- priate function of this channel in the insulin secretory process.
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| 7. |
- Börjesson, Thomas S., et al.
(author)
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Off-odorous compounds produced by molds on oatmeal agar : Identification and relation to other growth characteristics
- 1993
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In: Journal of Agricultural and Food Chemistry. - Washington : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 41:11, s. 2104-2111
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Journal article (peer-reviewed)abstract
- Ten Penicillium and Aspergillus species, four with a strong musty off-odor and six reference fungi without any characteristic odor, were cultivated on oatmeal agar for 5 days in cultivation vessels provided with an inlet and an outlet for air. Samples of volatile metabolites were collected on a porous polymer adsorbent attached to the outlet from day 2 through day 5 after inoculation. Adsorbed compounds were desorbed thermally and analyzed with GC/MS and a combined GC and sensory analysis, the GC sniff technique. Multivariate analysis of GC/MS and fungal odor data revealed strong associations between 6 of 65 volatile compounds and musty off-odor. The GC sniff technique showed that five of these, dimethyl disulfide, 1-octen-3-ol, 2-methylisoborneol, and two C11H18 compounds, had prominent off-odors. In addition, geosmin, 1-methoxy-3-methylbenzene, and methylphenol were produced in large amounts by some off-odorous fungi and contributed to their unpleasant odor. 3-Methylfuran, 2-methyl-1-propanol, and 3-methyl-1-butanol were much more commonly produced than the off-odorous compounds. Both odorous and other volatile metabolites could be detected after 2 days of fungal growth. The production of odorous metabolites was enhanced at the time of sporulation.
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| 8. |
- Doherty, Patrick, 1957-, et al.
(author)
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Fuzzy if-then-unless rules and their implementation
- 1993
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In: International Journal of Uncertainty Fuzziness and Knowledge-Based Systems. - : World Scientific. - 0218-4885. ; 1:2, s. 167-182
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Journal article (peer-reviewed)abstract
- We consider the possibility of generalizing the notion of a fuzzy If-Then rule to take into account its context dependent nature. We interpret fuzzy rules as modeling a forward directed causal relationship between the antecedent and the conclusion, which applies in most contexts, but on occasion breaks down in exceptional contexts. The default nature of the rule is modeled by augmenting the original If-Then rule with an exception part. We then consider the proper semantic correlate to such an addition and propose a ternary relation which satisfies a number of intuitive constraints described in terms of a number of inference rules. In the rest of the paper, we consider implementational issues arising from the unless extension and propose the use of reason maintenance systems, in particular TMS's, where a fuzzy If-Then-Unless rule is encoded into a dependency net. We verify that the net satisfies the constraints stated in the inference schemes and conclude with a discussion concerning the integration of qualitative IN-OUT labelings of the TMS with quantitative degree of membership labelings for the variables in question.
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| 9. |
- Ehnfors, Margareta, 1941-, et al.
(author)
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Nursing care as documented in patient records
- 1993
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In: Scandinavian Journal of Caring Sciences. - Oslo, Norway : Wiley-Blackwell. - 0283-9318 .- 1471-6712. ; 7:4, s. 209-20
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Journal article (peer-reviewed)abstract
- A review of 106 nursing records from 12 wards was conducted to categorize and quantify the content of the documentation and to consider the comprehensiveness of the recording for individual nursing problems. Audit instruments, based on a model for nursing documentation were developed and applied. The results show that admission assessment was missing in slightly less than half of all records, two-thirds had no nursing care plan and about one-third had no documentation on nursing outcome. About 90% of the records had no nursing diagnosis, no objective or no nursing discharge note. Notes on nursing status and nursing interventions were most common. Only one-third of the nursing problems identified had recording that gave information about the progress of the patient's problem. The analyses performed give information on the quality of nursing records which may be used to evaluate the quality of nursing care.
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| 10. |
- Gullberg, Mats T, et al.
(author)
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Ability to solve problems, professionalism, management, empathy, and working capacity in occupational therapy : The Professional Self Description Form
- 1994
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In: Scandinavian Journal of Caring Sciences. - : Wiley. - 0283-9318 .- 1471-6712. ; :8, s. 173-178
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Journal article (peer-reviewed)abstract
- The majority of occupational therapists in Sweden previously worked on large occupational therapy wards. Health care policy has changed over the years and the system has been reorganized accordingly. The employment situation for occupational therapists has also changed. This paper focuses on the perception of professional self among occupational therapists. The objective was to explore the professional self and to suggest components important to the occupational therapist profession. The Professional Self Description Form (PSDF) was used for the exploration of self. The 19 items in the PSDF cover areas relevant to professional functioning and activity. Sixty-eight employed occupational therapists participated. The results of the PSDF were subjected to factor analysis and five factors were obtained; Ability to solve problems, Professionalism, Management, Empathy, and Working capacity. We believe that these five factors can function as improving domains of the role of the professional occupational therapist in Sweden
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