| 1. |
- Pettersson, K, et al.
(författare)
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Free and complexed prostate-specific antigen (PSA) : in vitro stability, epitope map, and development of immunofluorometric assays for specific and sensitive detection of free PSA and PSA-alpha 1-antichymotrypsin complex
- 1995
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Ingår i: Clinical Chemistry. - 0009-9147. ; 41:10, s. 8-1480
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Tidskriftsartikel (refereegranskat)abstract
- Generation of 15 monoclonal antibodies (MAbs) allowed construction of epitope maps and specific two-site immunofluorometric assays for free prostate-specific antigen (PSA) and PSA complexed with alpha 1-antichymotrypsin (ACT). Close correlation of PSA concentrations obtained with the use of different assays of free PSA suggested extensive similarity in immunodetection of free PSA in serum. Assays of the PSA-ACT complex overestimated the concentration of PSA-ACT in serum because of nonspecific adsorbance of ACT or cathepsin G-complexed ACT to the solid phase. This interference was substantially decreased in the presence of heparin. In studying the stability of purified PSA and PSA-ACT complexes formed in vitro, we found that the free PSA was stable during storage for 4 weeks at 35 degrees C, whereas PSA-ACT complexes largely dissociated in these conditions. The instability of PSA-ACT complexes was counteracted by storage at low temperatures, by adjusting the pH of the storage buffer between 6.8 and 7.4, and through addition of 100-1000-fold molar excess of native ACT. The ease of calibration and the accuracy of free PSA assays in comparison with assays of the PSA-ACT complex suggest that measurements of free to total PSA most accurately reflect the inverse of the proportion of PSA complexed to ACT in serum.
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| 2. |
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| 3. |
- Lilja, H, et al.
(författare)
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Prostate-specific antigen in serum occurs predominantly in complex with alpha 1-antichymotrypsin
- 1991
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 37:9, s. 25-1618
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Tidskriftsartikel (refereegranskat)abstract
- Immunologic measurements of the serum concentration of prostate-specific antigen (PSA), an abundant prostatic-secreted serine proteinase, are frequently used to monitor patients with prostate cancer, though it has not been ascertained whether this immunoreactivity represents a PSA zymogen, the active proteinase, or PSA complexed to extracellular proteinase inhibitors. To characterize the PSA immunoreactivity in serum, we used monoclonal antibodies produced against PSA and a polyclonal rabbit IgG against alpha 1-antichymotrypsin in the design of three noncompetitive PSA assays: assay T, which detected PSA both when present as the active proteinase and when complexed to alpha 1-antichymotrypsin; assay F, which recognized the active proteinase but most poorly detected PSA complexed to alpha 1-antichymotrypsin; and assay C, which was specific for PSA complexed to alpha 1-antichymotrypsin. We used the three assays to measure PSA immunoreactivity in 64 patients' sera and in the effluent after gel chromatography of sera from four patients. This identified an 80- to 90-kDa complex between PSA and alpha 1-antichymotrypsin as the predominant fraction of the PSA immunoreactivity in blood plasma; an immunoreactive 25- to 40-kDa compound was the minor fraction.
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| 4. |
- Bjartell, A., et al.
(författare)
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Time-resolved fluorescence imaging (TRFI) for direct immunofluorescence of PSA and alpha-1-antichymotrypsin in prostatic tissue sections
- 1999
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Ingår i: Prostate Cancer and Prostatic Diseases. - : Springer Science and Business Media LLC. - 1365-7852 .- 1476-5608. ; 2:3, s. 140-147
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a direct immunofluorescence technique utilising chelates of the lanthanide ions europium and terbium conjugated to monoclonal IgGs (Mabs) against prostate-specific antigen (PSA) and alpha-1- antichymotrypsin (ACT) for the detection and quantification on the same tissue section. Strong signals without disturbance from tissue autofluorescence were demonstrated in paraffin sections of ten benign and six malignant prostate tissue specimens. The signal intensity increased linearly with the amount of labelled Mab until epitope saturation began. The highest concentrations of bound IgG in tissue sections were 27.3 fmol/pixel for ACT and 7.2 for PSA. Time-resolved fluorescence imaging (TRFI) offers an attractive method for histochemical studies based on specific and quantitative detection of fluorescent lanthanide chelates.
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| 5. |
- Dahlén, P, et al.
(författare)
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Sensitive detection of genes by sandwich hybridization and time-resolved fluorometry
- 1987
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Ingår i: Molecular and Cellular Probes. - : Elsevier BV. - 0890-8508 .- 1096-1194. ; 1:2, s. 159-168
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Tidskriftsartikel (refereegranskat)abstract
- Europium has been used as a non-radioactive marker in immunoassays as this metal can be detected with high sensitivity by time-resolved fluorometry. In this work streptavidin labeled with europium was used to detect biotinylated probes in a sandwich nucleic-acid hybridization assay with microtitration strips as the solid phase. pBR 322 plasmids were detected with a sensitivity of 4 × 105 molecules. As the sample is added in solution in sandwich hybridization, fast and simple sample pre-treatment can be used without encountering background problems. The method was applied to test bacterial samples of uropathogenic Escherichia coli strains for the presence of the β-lactamase gene.
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| 6. |
- Denmeade, Samuel R., et al.
(författare)
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Activation of latent protease function of pro-hK2, but not pro-PSA, involves autoprocessing
- 2001
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Ingår i: The Prostate. - : Wiley. - 0270-4137. ; 48:2, s. 122-126
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Human glandular kallikrein 2 (hK2) and prostate-specific antigen (PSA) are members of an extensive kallikrein family of proteases. Both proteases are secreted as zymogens or proenzymes containing a seven amino acid propeptide that must be proteolytically removed for enzymatic activation. The physiological proteases that activate pro-hK2 and pro-PSA are not known. METHODS: The pro-hK2 peptide sequence is Val-Pro-Leu-Ile-Gln-Ser-Arg (VPLIQSR). For PSA, the amino acid sequence of the propeptide is Ala-Pro-Leu-Ile-Leu-Ser-Arg (APLILSR). Fluorescent substrates were made by coupling these peptide sequences to 7-amino-4-methylcoumarin (AMC). The hydrolysis of the VPLIQSR-AMC and APLILSR-AMC substrates by hK2, PSA, and a panel of purified proteases was determined. RESULTS: HK2 readily cleaved the pro-hK2 peptide substrate VPLIQSR-AMC with a rate of hydrolysis that was approximately 8-fold higher than an equimolar amount of purified trypsin. HK2 also had the highest hydrolysis rate from among a group of other trypsin-like proteases. In contrast, neither hK2 nor PSA was able to appreciably cleave the pro-PSA substrate APLILSR-AMC. The pro-PSA substrate was most readily hydrolyzed by urokinase and trypsin. CONCLUSIONS: HK2 can hydrolyze the pro-hK2 substrate suggesting that maturation of pro-hK2 to enzymatically active hK2 involves autoprocessing. As expected, PSA, a chymotrypsin-like protease, was unable to hydrolyze either of the propeptide substrates. Therefore, it is unlikely that PSA can auto-process its own enzymatic function. HK2 has trypsin-like specificity but was unable to hydrolyze the pro-PSA substrate. These results raise the possibility that an additional processing protease may be required to fully process PSA to an enzymatically active form.
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| 7. |
- Denmeade, Samuel R., et al.
(författare)
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Specific and efficient peptide substrates for assaying the proteolytic activity of prostate-specific antigen
- 1997
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Ingår i: Cancer Research. - 0008-5472. ; 57:21, s. 4924-4930
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Tidskriftsartikel (refereegranskat)abstract
- Prostate-specific antigen (PSA) is a serine protease secreted by hath normal prostate glandular celts and prostate cancer cells. The major proteolytic substrates for PSA are the gel-forming proteins in semen, semenogelin (Sg) I and II. On the basis of the PSA cleavage map for Sg I and II, a series of small peptides (ie., ≤ 7 amino acids) was synthesized and coupled at the COOH terminus to 7-amino-4-methyl coumarin. Using these fluorescently tagged substrates, K(m)s and k(cm)s were determined for PSA hydrolysis, and the substrates were also tested for activity against a panel of purified proteases. Previously, a variety of chymotrypsin substrates have been used to assay the enzymatic activity of PSA. The present studies have identified a peptide sequence with a high degree of specificity for PSA (i.e., no detectable hydrolysis by chymotrypsin) and improved K(m)s and k(cat)s over previously used substrates. On the basis of these parameters, the best peptide substrate for PSA has the amino acid sequence HSSKLQ. Using PC-82 human prostate cancer xenografts and human prostate tissues, this PSA substrate was used to document that prostate cancer cells secrete enzymatically active PSA into the extracellular fluid but that once in the blood, PSA is not enzymatically active. On the basis of this information, it should be possible to use the HSSKLQ peptide as a carrier to target peptide- coupled prodrugs for selective activation within sites of PSA-secreting, metastatic prostate cancer cells and not within the blood or other nonprostatic normal tissues.
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| 8. |
- Krause-Jensen, D, et al.
(författare)
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Nordic Blue Carbon Ecosystems: Status and Outlook
- 2022
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 9
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Forskningsöversikt (refereegranskat)abstract
- Vegetated coastal and marine habitats in the Nordic region include salt marshes, eelgrass meadows and, in particular, brown macroalgae (kelp forests and rockweed beds). Such habitats contribute to storage of organic carbon (Blue Carbon – BC) and support coastal protection, biodiversity and water quality. Protection and restoration of these habitats therefore have the potential to deliver climate change mitigation and co-benefits. Here we present the existing knowledge on Nordic BC habitats in terms of habitat area, C-stocks and sequestration rates, co-benefits, policies and management status to inspire a coherent Nordic BC roadmap. The area extent of BC habitats in the region is incompletely assessed, but available information sums up to 1,440 km2 salt marshes, 1,861 (potentially 2,735) km2 seagrass meadows, and 16,532 km2 (potentially 130,735 km2, including coarse Greenland estimates) brown macroalgae, yielding a total of 19,833 (potentially 134,910) km2. Saltmarshes and seagrass meadows have experienced major declines over the past century, while macroalgal trends are more diverse. Based on limited salt marsh data, sediment C-stocks average 3,311 g Corg m-2 (top 40-100 cm) and sequestration rates average 142 g Corg m-2 yr-1. Eelgrass C-stocks average 2,414 g Corg m-2 (top 25 cm) and initial data for sequestration rates range 5-33 g Corg m-2, quantified for one Greenland site and one short term restoration. For Nordic brown macroalgae, peer-reviewed estimates of sediment C-stock and sequestration are lacking. Overall, the review reveals substantial Nordic BC-stocks, but highlights that evidence is still insufficient to provide a robust estimate of all Nordic BC-stocks and sequestration rates. Needed are better quantification of habitat area, C-stocks and fluxes, particularly for macroalgae, as well as identification of target areas for BC management. The review also points to directives and regulations protecting Nordic marine vegetation, and local restoration initiatives with potential to increase C-sequestration but underlines that increased coordination at national and Nordic scales and across sectors is needed. We propose a Nordic BC roadmap for science and management to maximize the potential of BC habitats to mitigate climate change and support coastal protection, biodiversity and additional ecosystem functions.
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| 9. |
- Lövgren, Janita, et al.
(författare)
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Production of recombinant PSA and HK2 and analysis of their immunologic cross-reactivity
- 1995
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Ingår i: Biochem Biophys Res Commun. - : Elsevier BV. ; 213:3, s. 888-895
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of prostate-specific antigen (PSA) in serum are widely used to monitor patients with prostate cancer, but the attenuation of the assay response by PSA complexed to protease inhibitors has been shown to affect the results in certain assay designs. Moreover, the human glandular kallikrein-2 (hK2), a kallikrein-like serine protease that is 80% similar to PSA, might interfere with the specific detection of PSA by immunological cross-reactivity. We have expressed hK2 and PSA in eucaryotic cells using the Semliki Forest Virus expression system and studied the reactivity of 18 monoclonal anti-PSA IgGs. Five of them cross-reacted with identical affinities to recombinant hK2 whereas 13 recognized PSA alone. The antibodies that recognized both PSA and hK2 bind to a region of the protein that is exposed when PSA is complexed to alpha-1-antichymotrypsin.
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| 10. |
- Rusaw, David, 1978-, et al.
(författare)
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Test-retest reliability of the Falls Efficacy Scale International for lower limb prosthesis users
- 2023
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Konferensbidrag (refereegranskat)abstract
- Introduction and ObjectiveFalling and the fear of falling are major issues for people with lower limb amputation. A number of tools have been developed to assess the fear of falling, these include The Falls Efficacy Scale – International (FES-I). As with any tool, it is important that the validity and reliability of the tool is established for specific target populations. The reliability of the FES-I has been established for multiple patients group. A previous study had established good relative reliability in a small sam- ple of lower limb prosthesis users (ICC = 0.87, 95% CI: 0.70-0.94) (Nugent et al. 2022). However, the current project aimed to evaluate the test-retest reliability and concurrent validity of the FES-I for lower limb prosthesis users with a larger sample. The current abstract outlines the assessment of test-retest reliability of the FES-I.Materials and MethodsForty lower limb prosthesis users with varying levels of amputation from Sweden (n=27) and England (n=13) completed an online questionnaire, which included the FES-I, on two separate oc- casions, separated by two weeks. Given the data distribution, Spearman’s rank correlation analysis was used to evaluate the test re-test reliability of the FES-I responses between these two occasions.ResultsA strong, positive, statistically significant correlation between the two occasions was indicated (rs (25)=0,902, p=< .001). This suggested that there was excellent test re-test reliability for the FES-I in a group of lower limb prosthesis users.ConclusionsThe FES-I shows excellent test-retest reliability (rs>.8) for lower limb prosthesis users, and re- searchers interested in utilizing this instrument can be confident in the reliability in this specific group. This is useful information, particularly for those involved in longitudinal assessment of falls efficacy.
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