| 1. |
- Löfberg, Helge, et al.
(författare)
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Demonstration and classification of amyloidosis in needle biopsies of the kidneys, with special reference to amyloidosis of the AA-type
- 1987
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 0108-0164. ; 95A:1-6, s. 357-363
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Tidskriftsartikel (refereegranskat)abstract
- To examine whether sequence-specific antibodies directed against serum amyloid A were useful in the demonstration and classification of amyloidosis, needle biopsy specimens from the kidneys of 152 cases with renal disorders were investigated using the avidin-biotin-peroxidase complex technique of immunohistochemistry. A distinct immunoreactivity of protein AA was seen in biopsies from all 42 individuals who were clinically classified as having the AA-type of amyloidosis. The stained areas coincided with deposits stained by Congo red. Four of these cases demonstrated immunoreactivity of both protein AA and light immunoglobulin chains and all biopsies except one showed immunoreactivity for the amyloid P-component. After treatment with potassium permanganate, the amyloid deposits in the biopsies of all 42 cases lost their affinity for Congo red. Ten patients with clinical and laboratory findings compatible with the AL-type of amyloidosis were also investigated. All their biopsies demonstrated Congophilic amyloid deposits but none of them showed any immunoreactivity of protein AA. Amyloid deposits of lambda light immunoglobulin chains-but not kappa-were demonstrated in biopsies from four patients. The amyloid P-component was found in biopsies from six individuals and positive Congo red staining after treatment with potassium permanganate was seen in biopsies from four of the cases. Biopsies of 100 patients suffering from non-amyloid renal disorders were also examined. None of them displayed any immunoreactive deposits of protein AA. The investigation shows that amyloid deposits of the AA-type can be identified in needle biopsies when sequence-specific antibodies against serum amyloid A are used in the avidin-biotin-peroxidase complex technique. Both the diagnostic sensitivity (42 of 42) and specificity (110 of 110) of the assay were optimal (1.0). The method was found to be superior to other investigated techniques and useful for classifying amyloidosis in formalin-fixed renal biopsies.
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| 2. |
- Peetre, Christina, et al.
(författare)
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A tumor necrosis factor binding protein is present in human biological fluids
- 1988
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Ingår i: European Journal of Haematology. - : Wiley. - 0902-4441 .- 1600-0609. ; 41:5, s. 414-419
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Tidskriftsartikel (refereegranskat)abstract
- Tumor necrosis factor (TNF) possesses both beneficial and toxic bioactivities. Mechanisms may operate to counteract harmful effects. We have identified a TNF binding protein (TNF-BP), which shows increased levels in serum and urine of patients on regular hemodialysis treatment (RDT). TNF-BP inhibited the specific binding of human recombinant TNF (rTNF) to its cell surface receptor. Results from gel chromatography demonstrated the presence in serum and urine of a macromolecule with an apparent molecular weight of 50,000, which formed a complex with rTNF. A 62-fold purification of TNF-BP from urine of patients on RDT was achieved by ion exchange chromatography and gel chromatography. Partially purified TNF-BP reduced the growth inhibitory effect of rTNF on a susceptible leukemia cell line. TNF-BP may act as a regulator of the biological activity of TNF and could have beneficial effects in certain inflammatory conditions.
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| 3. |
- Wirth, Michael, 1956, et al.
(författare)
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Interactions between DNA and mono-, bis-, tris-, tetrakis-, and hexakis(aminoacridines). A linear and circular dichroism, electric orientation relaxation, viscometry, and equilibrium study
- 1988
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 110:3, s. 932-939
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between DNA and a series of mono-, bis-, tris-, tetrakis-, and hexakis-intercalating 9-aminoacridines has been studied with flow linear dichroism (LD), circular dichroism (CD), electric orientation relaxation (EOR) techniques, and with viscometry and equilibrium analyses. The orientation of the 9-aminoacridine ligand relative to the average orientation of the DNA bases, measured by LD, shows that with both 9-aminoacridine and the bis(acridines) the in-plane short axes of the acridine ligands are oriented perfectly parallel to the planes of the DNA bases, as expected for classical intercalation, whereas the long axes are found to be significantly tilted. This is supported by the DNA lengthening measured by EOR, which for 9-aminoacridine is 1.5 base-pair units, compared with 1.0 for ethidium bromide. Also in case of the tris(acridines) LD, CD, viscometry, and equilibrium data indicate that all acridine ligands are intercalated. The binding analysis shows an increasing degree of cooperativity in the sequence 9-aminoacridine < bis(acridines) < tris(acridines), and the corresponding binding densities, 4, 8, and 11–14, respectively, are in good agreement with those expected from the nearest-neighbor exclusion principle. The LD and CD measurements show that the tetrakis- and hexakis(acridines), despite long and flexible links, bind to DNA with only three of the acridine ligands intercalated.
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| 4. |
- Grubb, Anders, et al.
(författare)
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Production of an amino acid sequence-specific antiserum against human amyloid A (AA) and serum amyloid A (SAA) protein
- 1987
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - 0036-5513. ; 47:6, s. 619-626
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Tidskriftsartikel (refereegranskat)abstract
- The hydrophilic nonapeptide Ser-Asp-Ala-Arg-Glu-Asn-Ile-Gln-Arg, identical with residues 59-67 of human amyloid protein A (AA) and serum amyloid protein A (SAA), was covalently bound via its carboxyl-terminal end to the carrier-protein keyhole limpet haemocyanin. The complex was injected subcutaneously into ten rabbits. All rabbits produced antisera which, unabsorbed, were specific for AA and SAA. The antisera and their isolated peptide specific antibodies were performance-tested and found to be excellent for demonstration of AA and SAA in immunoblotting and immunohistochemical techniques but unsuitable for immunoprecipitation. Since it is difficult to produce AA- and SAA-specific antisera by procedures earlier described and commercial supplies of good such reagents are unavailable, the easy production of sequence-specific such antisera will facilitate more extended studies of the corresponding antigens for diagnostic and scientific purposes.
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| 5. |
- Löfberg, Helge, et al.
(författare)
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The prevalence of renal amyloidosis of the AA-type in a series of 1,158 consecutive autopsies
- 1987
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 0108-0164. ; 95A:1-6, s. 297-302
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Tidskriftsartikel (refereegranskat)abstract
- To determine the prevalence of renal amyloidosis of the AA-type in a defined population, formalin-fixed specimens from the kidneys of all the cases autopsied in 1983 at The General Hospital of Malmö, Sweden, were investigated using immunohistochemical techniques. Amyloid deposits of protein AA were found in 10 of 1,158 investigated cases and the calculated prevalence was 0.86 per cent. The mean age at death of the individuals with the AA-type of amyloidosis was 79 years. Six of the cases with amyloidosis had rheumatoid arthritis. The avidin-biotin-peroxidase complex technique was found to be superior to the immunofluorescence method and a high sensitivity and specificity was achieved when sequence-specific antibodies against a synthetized nonapeptide corresponding to a hydrophilic segment of the polypeptide chain of protein AA were used in the assay. Nine cases with other types of amyloid deposits in the kidneys were also detected. None of these cases showed any AA immunoreactivity but all of them demonstrated Congophilic deposits which were immunohistochemically stained by antibodies against the amyloid P-component. The prevalence of renal amyloidosis comprising all types of amyloid protein deposits was 1.64 per cent.
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| 6. |
- Gabrielsson, Britt, 1957, et al.
(författare)
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Effects of divalent metal ions on the uptake of glutamate and GABA from synaptosomal fractions
- 1986
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Ingår i: Brain Research. - 0006-8993. ; 384:2, s. 218-23
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Tidskriftsartikel (refereegranskat)abstract
- The effects of divalent metal ions on high affinity uptake glutamate and GABA were examined, using crude and purified synaptosomal fractions prepared from brains of DBA/2CBI. The uptake velocities of both amino acids are severely reduced in the presence of Cu2+, Fe2+ and Zn2+ but remain unaffected by Co2+.
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| 7. |
- Nilsson Ekdahl, Kristina, et al.
(författare)
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Effects of epinephrine, glucagon and insulin on the activity and degree of phosphorylation of fructose-1,6-bisphosphatase in cultured hepatocytes.
- 1987
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Ingår i: Biochimica et Biophysica Acta. Molecular Cell Research. - 0167-4889 .- 1879-2596. ; 929:3, s. 318-326
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Tidskriftsartikel (refereegranskat)abstract
- The effects of epinephrine, glucagon and insulin on the activity and degree of phosphorylation of fructose-1,6-bisphosphatase in isolated hepatocytes maintained in cell culture for 24 h were investigated. Epinephrine caused a rapid decrease in the apparent Km monitored as the activity ratio between the activity at 12.5 and 83 microM fructose-1,6-bisphosphate, reaching a maximum after 5 min. Glucagon caused a slower and less pronounced activation, and insulin caused an equally slow increase in Km. The effect of epinephrine and glucagon was completely reciprocated by insulin and the action of insulin was totally erased by the other two. Glucagon stimulated the incorporation of [32P]phosphate into fructose-1,6-bisphosphatase from about 2.5 to 4.2 mol/mol enzyme and epinephrine to 3.5 mol/mol. The effect of the two hormones acting together was cumulative. Insulin brought about a decrease in the degree of phosphorylation to 2.0 mol/mol. The effect of epinephrine was shown to be caused by the beta-receptors, since it was completely blocked by propanolol (a beta-antagonist) and remained unaffected by the presence of phentolamine (an alpha-antagonist).
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| 8. |
- Nilsson Ekdahl, Kristina, et al.
(författare)
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Fructose-1,6-bisphosphatase from rat liver. A comparison of the kinetics of the unphosphorylated enzyme and the enzyme phosphorylated by cyclic AMP-dependent protein kinase.
- 1985
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 260, s. 14173-14179
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Tidskriftsartikel (refereegranskat)abstract
- A purification procedure for rat hepatic fructose-1,6-bisphosphatase, described earlier, has been improved, resulting in an enzyme preparation with a neutral pH optimum and with both phosphorylatable serine residues present. The subunit Mr was 40,000. Phosphorylation in vitro with cyclic AMP-dependent protein kinase resulted in the incorporation of 1.4 mol of phosphate/mol of subunit and led to an almost 2-fold decrease in apparent Km for fructose-1,6-bisphosphate. In contrast to yeast fructose-1,6-bisphosphatase, fructose-2,6-bisphosphate had no effect on the rate of phosphorylation or dephosphorylation of the intact enzyme. The effects of the composition of the assay medium, with regard to buffering substance and Mg2+ concentration, on the apparent Km values of phosphorylated and unphosphorylated enzyme were investigated. The kinetics of phosphorylated and unphosphorylated fructose-1,6-bisphosphatase were studied with special reference to the inhibitory effects of adenine nucleotides and fructose-2,6-bisphosphate. Unphosphorylated fructose-1,6-bisphosphatase was more susceptible to inhibition by both AMP and fructose 2,6-bisphosphate than phosphorylated enzyme, at high and low substrate concentrations. Both ATP and ADP had a similar effect on the two enzyme forms, ADP being the more potent inhibitor. Finally, the combined effect of several inhibitors at physiological concentrations was studied. Under conditions resembling the gluconeogenic state, phosphorylated fructose-1,6-bisphosphatase was found to have twice the activity of the unphosphorylated enzyme.
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