| 1. |
- Graham, J. B., et al.
(författare)
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The Malmo polymorphism of coagulation factor IX, an immunologic polymorphism due to dimorphism of residue 148 that is in linkage disequilibrium with two other F.IX polymorphisms
- 1988
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Ingår i: American Journal of Human Genetics. - 0002-9297. ; 42:4, s. 573-580
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Tidskriftsartikel (refereegranskat)abstract
- A mouse monoclonal antibody (MAB 9,9) to coagulation factor IX (F.IX) detects a polymorphism in the plasma of normal people. Its epitope has been narrowed down to <6 amino acids in the activation peptide of the X-linked F.IX protein. The activation peptide contains a dimorphism - Thr:Ala - at position 148 of the protein. Using synthetic oligonucleotides, we have demonstrated that (1) the F.IX which reacts with 9.9 has Thr at position 148 and (2) that which does not has Ala. Positive reactors (148(thr)) are designated Malmo A, and negative reactors (148(ala)) are designated Malmo B. The plasma levels of AA women are indistinguishable from those of A men, and both B men and BB women are null against MAB 9.9. The plasma level of Malmo A in AB women is approximately half that of AA women, and 'lyonization' is clearly operating in the heterozygotes. The dimorphism is in strong linkage disequilibrium with two other intragenic RFLPs, TaqI and XmnI. Furthermore, intragenic crossing-over - including double crossing-over - appears to have occurred between the three sites. Seven of the eight possible haplotypes have been identified, five in men and two others in women. The immunoassay that identifies ~50% of the AB women in the pool of Malmo A females with 95% confidence identifies men unambiguously as A or B. The assay would be very useful for population-genetic studies of the Malmo epitope if the studies were limited to men.
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| 2. |
- Molin, M, et al.
(författare)
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Mercury, selenium, and glutathione peroxidase in dental personnel.
- 1989
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Ingår i: Acta Odontologica Scandinavica. - 0001-6357 .- 1502-3850. ; 47:6, s. 383-90
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Tidskriftsartikel (refereegranskat)abstract
- Eighteen persons, dentists and nurses, with urinary mercury levels higher than the group median value of all dental personnel in the country of Västerbotten were compared with a group consisting of 15 persons with low urinary mercury levels working in the same clinics. A statistically significant difference between the high urinary mercury group and the low urinary mercury group could be seen in the plasma mercury level. In each group a statistically significant relation could be seen between the plasma mercury level and the total number of amalgam surfaces. The two groups did not differ with regard to the levels of plasma selenium and erythrocyte glutathione peroxidase, and no correlation between these two variables and the plasma mercury levels could be found. To evaluate organ functions, a large number of supplementary analyses were performed. These analyses did not indicate any influence on organ functions. Although the persons in the present study were occupationally exposed to mercury, none of the biologic variables analyzed seemed to be affected. Even among dental personnel who handle amalgam professionally the number of amalgam surfaces is a major contributory factor to the P-mercury level.
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| 3. |
- Clarke, D J, et al.
(författare)
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Synaptogenesis of grafted cholinergic neurons
- 1987
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 495:1, s. 268-282
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Falkenberg, C, et al.
(författare)
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Purification of streptococcal protein G expressed by Escherichia coli by high performance liquid affinity chromatography using immobilized immunoglobulin G and albumin
- 1987
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 2:5, s. 5-221
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Tidskriftsartikel (refereegranskat)abstract
- A one-step HPLC method was developed for the purification of protein G, a cell wall molecule from group C and G streptococci with immunoglobulin G- and albumin-binding properties. Lysed Escherichia coli bacteria infected with lambda-phages containing the protein G gene from group G streptococci were used as a starting material for the preparations. The lysate was applied to a column with immobilized human immunoglobulin G or human serum albumin. Protein G was selectively bound and eluted at pH 2.0. A 750-fold purification was achieved. Sodium dodecylsulfate + polyacrylamide gel electrophoresis showed that the highly purified protein G consisted of three sets of doublets with the apparent molecular weight of 64 and 67, 56 and 58, and 45 and 47 kilodaltons, respectively. A specific method for quantitation of small amounts of protein G was developed and used for specific tracing of the protein after the affinity chromatography. Goat polyclonal antibodies were bound to an antigen coated to the plastic walls of microtiter plates, causing the Fc-region of the immunoglobulins to be directed outwards. Unknown samples of protein G were then allowed to compete with radio-iodinated protein G (solid phase radioassay) or protein G coupled to alkaline phosphatase (enzyme linked sorbent assay) for the Fc-regions.
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| 5. |
- Fredrikson, G, et al.
(författare)
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Use of protein G for preparation and characterization of rabbit antibodies against rat adipose tissue hormone-sensitive lipase
- 1987
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Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 0022-1759. ; 97:1, s. 65-70
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Tidskriftsartikel (refereegranskat)abstract
- The newly described immunoglobulin G-binding streptococcal surface protein, protein G, was used to prepare and characterize rabbit antibodies. The antibodies were directed against rat hormone-sensitive lipase, the rate-limiting enzyme in the hydrolysis of the triacylglycerols stored in adipose tissue. Antiserum was obtained after two injections with 20 micrograms enzyme protein, and the immunoglobulin fraction was obtained using a protein G-based solid-phase radioimmunoassay. The hydrolysis of acylglycerols by the enzyme was inhibited by the antibodies, and the enzyme could be efficiently removed from a solution using the antibodies and heat-killed streptococci expressing surface protein G. By Western blot and detection with 125I-protein G, the antibodies were found to selectively bind to hormone-sensitive lipase and to a smaller extent to two minor contaminants, possibly proteolytic fragments of the lipase. The amount of 125I-labelled protein G bound to the lipase on the blot was quantitatively related to the amount of enzyme protein down to the detection limit 10 ng.
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| 6. |
- Goobar, E., et al.
(författare)
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Measurement of a VPE-transported DFB laser with blue-shifted frequency modulation response from DC to 2 GHz
- 1988
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Ingår i: Electronics Letters. - 0013-5194 .- 1350-911X. ; 24, s. 746-747
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Tidskriftsartikel (refereegranskat)abstract
- The frequency modulation characteristics of a VPE-transported 1.53 mu;m wavelength GaInAsP-InP DFB semiconductor diode laser was measured. Below approximately 0.7 mW optical output power per facet, it exhibited a smooth, blue-shifted, frequency modulation response from DC to 2 GHz. In the modulation frequency range of 10 MHz to 100 MHz it exhibited a | Delta;f/ Delta;I| of 0.5-1.8 GHz/mA, depending on the biasing level
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| 7. |
- Goobar, E., et al.
(författare)
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Pure frequency modulation or intensity modulation with suppressed frequency chirp using active Bragg reflector integrated laser
- 1989
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 25, s. 304-305
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Tidskriftsartikel (refereegranskat)abstract
- The modulation properties of a laser structure which consists of an active Bragg reflector (300 mu m) integrated with an uncorrugated gain region (600 mu m) have been measured. The laser exhibited a flat FM response and very low spurious intensity modulation when modulating the current in the Bragg reflector. Furthermore, broadband intensity modulation with suppressed frequency chirp could also be achieved. An inhomogeneous linewidth enhancement factor alpha caused by the uneven carrier density distribution between the two sections gives a qualitative explanation to our results.
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| 8. |
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| 9. |
- Sandler, S, et al.
(författare)
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Cryopreservation of mouse pancreatic islets : effects of human serum on islet survival.
- 1987
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Ingår i: Upsala Journal of Medical Sciences. - 0300-9734 .- 2000-1967. ; 92:2, s. 177-184
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare the survival of cryopreserved mouse pancreatic islets frozen in the presence of either a simple salt solution (Hanks' balanced salt solution) or a complete tissue culture medium (RPMI 1640). Moreover, the addition of 10% human serum to the freezing solutions was evaluated. Collagenase isolated islets were kept in culture for three days, before being cooled at a rate of 5 degrees C/min or 25 degrees C/min to -70 degrees C, at which temperature the islets were transferred to liquid nitrogen. All freezing media were supplemented with 2 M dimethylsulphoxide as cryoprotectant. The islets were rapidly thawed at 37 degrees C and subsequently cultured for another three days. The recovery of islets was higher when the more rapid cooling rate was used and the addition of serum further improved the recovery. Compared to non-frozen cultured islets there was a loss of cells in all groups of cryopreserved islets, as measured by their DNA content, and this was accompanied by a lowered insulin content. All groups of frozen-thawed islets responded to a high glucose stimulus in vitro with a 5-9 fold increase in insulin secretion. There was no obvious advantage of using a complete tissue culture medium for islet cryopreservation, but the addition of serum had some beneficial effects. Data obtained from non-frozen control islets suggest that human serum slightly impairs the function of mouse pancreatic B-cells.
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| 10. |
- Valdemarsson, S, et al.
(författare)
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Platelet and adipocyte thermogenesis in hypothyroid patients: a microcalorimetric study
- 1985
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Ingår i: Acta Endocrinologica. - 0001-5598. ; 108:3, s. 361-366
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Tidskriftsartikel (refereegranskat)abstract
- Direct microcalorimetry was used for measurements of heat production in cell suspensions of platelets and adipocytes, obtained from hypothyroid patients before and after 3 months on full L-thyroxine substitution. Platelet heat production was significantly lower than normal before treatment and increased in all 10 patients studied; the mean value increased from 51.3 +/- 1.6 fW/cell before to 57.1 +/- 1.8 fW/cell after therapy (P less than 0.001). Similarily, adipocyte heat production was initially significantly lower than normal and increased during treatment in all 6 patients investigated. The mean value for heat production per adipocyte was 18.8 +/- 1.7 pW/cell before and 32.4 +/- 2.5 pW/cell after therapy (P less than 0.025), which is still below the level recorded in lean healthy subjects. The adipocyte size did not change significantly. The increase in adipocyte heat production was correlated to the increase in S-triiodothyronine levels (r = 0.84, P less than 0.05). In hypothyroidism, the total metabolic activity seems to be comparatively more reduced in adipocytes than in platelets. A difference may exist between these cells with regard to recovery of normal metabolic activity during treatment for hypothyroidism. Direct microcalorimetry appears to be an adequate method for monitoring net metabolic effects of thyroid hormones in these cells.
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