| 1. |
- Ali, L, et al.
(författare)
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Free and bound sodium in pancreatic beta-cells exposed to glucose and tolbutamide.
- 1989
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - 0006-291X .- 1090-2104. ; 164:1, s. 212-8
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Tidskriftsartikel (refereegranskat)abstract
- The effects of glucose and tolbutamide on the sodium handling of the pancreatic beta-cells were evaluated by measuring the total sodium content in intact islets from ob/ob-mice by integrating flame photometry and the free ion in individual beta-cells by dual wavelength fluorometry. Whereas increasing the glucose concentration from 3 to 20 mM resulted in a lowering of sodium, the addition of 100 microM tolbutamide caused a rise. The above-mentioned effects were most marked (about 50%) for the physiologically significant free sodium. The data indicate a more important role for Na+ in the regulation of insulin release than so far acknowledged. Increase of Na+ may contribute to the secretory response to hypoglycemic sulfonylureas by providing an additional rise of cytoplasmic Ca2+.
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| 2. |
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| 3. |
- Lund, P E, et al.
(författare)
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Leucine induces initial lowering of cytoplasmic Ca2+ in pancreatic beta-cells without concomitant inhibition of insulin release.
- 1989
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Ingår i: Biochemistry international. - 0158-5231. ; 19:1, s. 83-7
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Tidskriftsartikel (refereegranskat)abstract
- The early effects of glucose and leucine on cytoplasmic Ca2+ and insulin release were compared in suspensions of cells prepared by dispersal of the beta-cell-rich pancreatic islets of ob/ob-mice. Adequate temporal resolution was achieved by continuously recording the 340/380 nm fluorescence excitation ratio from cells loaded with the Ca2+ indicator fura-2 and measuring insulin in the perifusate from cells mixed with polyacrylamide beads. Raising the glucose concentration from 3 to 20 mM resulted in concomitant reductions of cytoplasmic Ca2+ and insulin release during the first minute. Whereas 10 mM leucine was as efficient as glucose in inducing temporary lowering of cytoplasmic Ca2+, this amino acid did not depress insulin release. It is concluded that the initial decrease of cytoplasmic Ca2+ is a phenomenon coupled to stimulation of the metabolism. The leucine-induced lowering of Ca2+ may essentially reflect changes in cytoplasmic pools other than in a peripheral one regulating insulin release.
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| 4. |
- Behrens, K., et al.
(författare)
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Reflection seismic measurements across the Granulite Belt of the POLAR Profile in the northern Baltic Shield, Northern Finland
- 1989
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Ingår i: Tectonophysics. - : Elsevier BV. - 0040-1951 .- 1879-3266. ; 162:1-2, s. 101-111
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Tidskriftsartikel (refereegranskat)abstract
- Reflection seismic measurements were carried out in 1985 on the central part of the POLAR refraction seismic profile in Northern Finland. The survey was planned and executed jointly by the Universities of Helsinki, Uppsala and Hamburg, using digital equipment with a total of 144 channels. By repeating the shots and moving the geophone spreads every day we were able to observe a 42-50 km recording spread. Referred to reflection elements, a line of 84 km total length through the source-receiver midpoints was recorded. We processed the results up to normal moveout-corrected time sections.A number of reflectors dipping 8°-15° to the northeast were recorded in the Lapland Granulite Belt range. These represent a system of sheared granulites which were observed on the surface in the southern part of the profile. From gravity modelling, the bottom of the dipping layers coincides with the lower boundary of the granulites. Between the depths of 22 and 35 km the crust in this area seems to be transparent to seismic signals. This leads to the assumption that the middle part of the crust is characterized by gentle velocity and density gradients. The crust-mantle boundary seems to be a layered Moho with good reflectors lying at depths between 40 and 44 km.
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| 5. |
- Kimberling, William J., et al.
(författare)
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Usher syndrome : clinical findings and gene localization studies
- 1989
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Ingår i: The Laryngoscope. - : Wiley. - 0023-852X .- 1531-4995. ; 99:1, s. 66-72
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Tidskriftsartikel (refereegranskat)abstract
- The issue of genetic heterogeneity is a critical problem in the localization of the gene(s) for Usher syndrome. Based on the data obtained on families studied to date, the differences between type I and type II Usher syndrome appear quite distinct with regard to auditory and vestibular function. Although the majority of families can be confidently diagnosed as typical type I or type II, clinical investigations revealed four families with findings that did not fit into either of the two more common subtypes. These findings emphasize the critical importance of an indepth clinical analysis concomitant with the linkage investigation to assure accurate subtyping of Usher syndrome. Based on an analysis of only those families with definite type I or type II Usher syndrome, approximately 17% of the genome can be excluded as a potential site of the gene for type I, and 14% can be excluded as the site for the type II gene. This study will continue until the Usher gene(s) is successfully localized.
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| 6. |
- Lund, B, et al.
(författare)
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Differential expression of interferon genes in a substrain of Namalwa cells.
- 1985
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Ingår i: Journal of interferon research. - 0197-8357. ; 5:2, s. 229-38
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Tidskriftsartikel (refereegranskat)abstract
- A substrain of Namalwa cells producing a high ratio of beta-interferon (IFN-beta) versus alpha-interferon (IFN-alpha) was investigated by constructing a cDNA library after induction with Sendai virus. The library was screened by two synthetic oligonucleotides, one specific for IFN-alpha and one complementary to both IFN-alpha and IFN-beta. Rescreening the library with two full-length cDNAs encoding IFN-alpha and IFN-beta, respectively, revealed that the frequency of the IFN-alpha and IFN-beta clones reflected the activities of IFN-alpha and IFN-beta obtained by functional assays. On the cDNA level, the dominating species was identical with the type of IFN-alpha A or IFN-alpha 2; however, one new type of cDNA also was found that was similar to the previously described IFN-alpha C. Only one type of cDNA was found encoding IFN-beta, although several IFN-beta proteins have been detected in the analyzed cell line.
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