| 1. |
- Andersson, N. E., et al.
(författare)
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Methodological considerations on the determination of the APC response in plasma
- 1995
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Ingår i: Infusionstherapie und Transfusionsmedizin. - : S. Karger AG. - 1019-8466. ; 22:SUPPL. 1, s. 80-82
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Tidskriftsartikel (refereegranskat)abstract
- The performance of COATEST® APC® Resistance on different coagulation instruments has been further evaluated through analysis of plasma from 100 blood donors on KC 10, ST 4, ACL 300R, Electra 900 and Thrombolyzer. The electromechanical instruments KC-10 and ST 4 showed a lower response to APC than the turbidimetric or photometric instruments with median APC ratios of 2.7 and 2.8 for the two former versus 3.1, 3.4 and 3.5, respectively, for the other three, which is in agreement with earlier initial findings. Similarly, the cut-off value varied between 2.1 and 2.6 for these instruments. The correlation of APC ratios between instruments was strong with r values ranging between 0.71 and 0.93 and, furthermore, none of the six plasmas with the lowest APC ratios on the Thrombolyzer ranked higher than 8 on any of the other instruments. Analysis of control plasmas with six consecutive kit batches on ACL and ST4 resulted in APC ratio ranges of 3.3-3.7 and 2.7-3.0 for a normal control and 1.8-2.0 and 1.9-2.0 for an abnormal control on ACL and ST4, respectively, illustrating a high reproducibility between batches. Repeated freezing and thawing of samples is disrecommended since this often resulted in increased APC ratios. In contrast, in spite of up to 40% decrease in FVIII activity upon storage of 10 different plasma samples for 5 h, the effect on the APC ratio was only minor as was also the effect of addition of 1.0 IU/ml of FVIII. In neither case was any sample misclassified. Altogether, the results support the applicability of this kit for measuring the response of plasma to APC.
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| 2. |
- Blom, Anna, et al.
(författare)
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Mutations in alpha-chain of C4BP that selectively affect its factor I cofactor function
- 2003
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:44, s. 43437-43442
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Tidskriftsartikel (refereegranskat)abstract
- C4b-binding protein (C4BP) inhibits all pathways of complement activation, acting as a cofactor to the serine protease factor I (FI) in the degradation of activated complement factors C4b and C3b. C4BP is a disulfide-linked polymer of seven alpha-chains and a unique beta-chain, the alpha- and beta-chains being composed of eight and three complement control protein (CCP) domains, respectively. In previous studies we have localized cofactor activity and binding of C4b to alpha-chain CCP1-3 of C4BP, whereas the binding of C3b required additionally CCP4. Likewise, introduced point mutations that decreased binding of C4b/C3b caused a decrease in cofactor activity. In the present study, we describe two mutants of C4BP, K126Q/K128Q and F144S/F149S, clustered on alpha-chain CCP3, which selectively lost their ability to act as cofactors in the cleavage of both C4b and C3b. Both mutants show the same binding affinity for C4b/C3b as measured by surface plasmon resonance and have the same inhibitory effect on formation and decay of the classical pathway C3-convertase as the wild type C4BP. It appears that C4b and C3b do not undergo the same conformational changes upon binding to the C4BP mutants as during the interaction with the wild type C4BP, which then results in the observed loss of the cofactor activity.
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| 3. |
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| 4. |
- He, X., et al.
(författare)
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The gene encoding vitamin K-dependent anticoagulant protein C is expressed in human male reproductive tissues
- 1995
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Ingår i: Journal of Histochemistry and Cytochemistry. - : SAGE Publications. - 0022-1554 .- 1551-5044. ; 43:6, s. 563-570
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Tidskriftsartikel (refereegranskat)abstract
- Protein C is a vitamin K-dependent protein circulating in plasma as a zymogen to an anticoagulant serine protease. After its activation, protein C cleaves and inactivates coagulation factors Va and VIIIa. Human protein C is synthesized in liver and undergoes extensive post-translational modification during its synthesis. Recently, the protein C inhibitor was demonstrated to be synthesized in several organs of the human male reproductive tract. Moreover, vitamin K-dependent protein S, which functions as a co-factor to activated protein C, was found to be synthesized in the Leydig cells of human testis. The aim of this study was to elucidate whether the protein C gene is also expressed in the male reproductive system. Specific immunostaining of protein C was found in Leydig cells of human testis, in the excretory epithelium of epididymis, and in some epithelial glands of the prostate, whereas no immunostaining was detected in seminal vesicles. Northern blotting and non-radioactive in situ hybridization demonstrated protein C mRNA in Leydig cells, in the excretory epithelium of epididymis, and in some of the epithelial glands of the prostate. The mRNA was distributed perinuclearly and the localization was in accordance with the specific immunostaining for protein C. The epithelium of epididymis was also found to contain both protein S mRNA and immunoreactivity. The demonstration of both protein C and protein S immunoreactivities, as well as their mRNAs, in male reproductive tissues suggests as yet unknown local functions for these proteins.
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| 5. |
- Juzeniene, Asta, et al.
(författare)
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Solar radiation and human health
- 2011
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Ingår i: Reports on Progress in Physics. - : IOP Publishing. - 0034-4885 .- 1361-6633. ; 74:6
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Forskningsöversikt (refereegranskat)abstract
- The Sun has played a major role in the development of life on Earth. In Western culture, people are warned against Sun exposure because of its adverse effects: erythema, photoimmunosuppression, photoageing, photocarcinogenesis, cataracts and photokeratitis. However, Sun exposure is also beneficial, since moderate doses give beneficial physiological effects: vitamin D synthesis, reduction of blood pressure and mental health. Shortage of Sun exposure may be even more dangerous to human health than excessive exposure. Avoiding Sun exposure leads to vitamin D deficiency which is associated not only with rickets and osteomalacia, but also with increased risk of cardiovascular disease, multiple sclerosis, rheumatoid arthritis, diabetes, influenza, many types of cancer and adverse pregnancy outcomes. Solar radiation induces nitric oxide release in tissue and immediate pigment darkening which certainly play important roles, although these are still unknown. Action spectra relevant for health are described. We will also review what is known about spectral and intensity variations of terrestrial solar radiation as well as its penetration through the atmosphere and into human skin and tissue.
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| 6. |
- Lundwall, Åke, et al.
(författare)
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Isolation and sequence of the cDNA for human protein S, a regulator of blood coagulation
- 1986
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Ingår i: Proc Natl Acad Sci U S A. ; 83:18, s. 20-6716
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Tidskriftsartikel (refereegranskat)abstract
- Protein S is a cofactor of activated protein C; together they function as a regulator of blood coagulation. A human liver cDNA library constructed in bacteriophage lambda gt11 was screened with DNA fragments from a full-length bovine cDNA clone encoding protein S. Several cDNA clones were isolated and sequenced. The combined cDNA sequences encoded the mature protein and 15 residues of the leader sequence when compared to bovine protein S. Human protein S is a single-chain protein consisting of 635 amino acids with 82% homology to bovine protein S. After an NH2-terminal gamma-carboxyglutamic acid-containing region, there is a short region with thrombin-sensitive bond(s), followed by a region with four repeat sequences that are homologous to the precursor of mouse epidermal growth factor. In contrast to the other vitamin K-dependent plasma proteins, the COOH-terminal portion of human protein S does not show any resemblance to serine proteases.
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| 7. |
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