| 1. |
- Buttle, D J, et al.
(författare)
-
Levels of neutrophil elastase and cathepsin B activities, and cystatins in human sputum: relationship to inflammation
- 1990
-
Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - 1502-7686. ; 50:5, s. 509-516
-
Tidskriftsartikel (refereegranskat)abstract
- Sputum samples from 25 patients with bronchiectasis were assayed enzymatically for myeloperoxidase, neutrophil elastase and cathepsin B, and immunologically for cystatin A, cystatin B, cystatin C, cystatin S and kininogen. High myeloperoxidase and neutrophil elastase levels were found in those sputum samples that were assessed visually to be purulent. These samples were also found to contain high levels of cathepsin B activity and cystatin A, but low levels of cystatin S and of the most effective cathepsin B inhibitor, cystatin C. In contrast, sputum samples that were low in myeloperoxidase and neutrophil elastase activities had low levels of cathepsin B and cystatin A, but high cystatin C and S levels. It is concluded that cathepsin B activity in sputum is positively correlated with the degree of inflammation and neutrophil recruitment. Although this may be due in part to reduced amounts of cathepsin B inhibitors, particularly cystatin C, theoretical considerations suggest that factors other than the gross level of inhibitors must be involved in the control of cathepsin B activity.
|
|
| 2. |
- Ekström, Ulf, et al.
(författare)
-
Insufficient mixing of thawed serum samples leading to erroneous results - experience from a field study and use of a correction procedure
- 2020
-
Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 80:2, s. 99-105
-
Tidskriftsartikel (refereegranskat)abstract
- Incorrect analysis results that are close to expected might not be recognized in scientific studies or routine patient care. In two field studies we obtained unexpected results in a large number of samples. The present study aimed to identify the source of error in the samples from these studies and to validate a method to obtain correct results. Pre-analytical procedures were scrutinized, giving no indications of inappropriate pre-analytical sample handling in the field or during transport in a tropical climate. Using a new set of samples from volunteers in simulation experiments, we observed the known concentration gradient of analytes sampled in gel as well as plain tubes after freezer storage and thawing. Experiments demonstrated that mixing of samples by vortexing alone was not sufficient to disrupt the gradient formed by freezing and thawing, which appeared to cause the problem encountered when we in field studies analyzed and biobanked large sample sets by robot pipetting. A correction procedure was introduced, in which the obtained value of an analyte was multiplied by a correction factor calculated for each sample using the expected sodium level (140 mmol/L) divided by the measured sodium value. When it was validated on results from the simulation experiments, we repeatedly found that the correction lead to results very close to true values for analytes of different size and charge. Usefulness of the procedure was demonstrated when applied to a large set of field study results.
|
|
| 3. |
- Leion, Felicia, et al.
(författare)
-
Estimating glomerular filtration rate (GFR) in children. The average between a cystatin C- and a creatinine-based equation improves estimation of GFR in both children and adults and enables diagnosing Shrunken Pore Syndrome.
- 2017
-
Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 77:5, s. 338-344
-
Tidskriftsartikel (refereegranskat)abstract
- Estimating glomerular filtration rate (GFR) in adults by using the average of values obtained by a cystatin C- (eGFRcystatin C) and a creatinine-based (eGFRcreatinine) equation shows at least the same diagnostic performance as GFR estimates obtained by equations using only one of these analytes or by complex equations using both analytes. Comparison of eGFRcystatin C and eGFRcreatinine plays a pivotal role in the diagnosis of Shrunken Pore Syndrome, where low eGFRcystatin C compared to eGFRcreatinine has been associated with higher mortality in adults. The present study was undertaken to elucidate if this concept can also be applied in children. Using iohexol and inulin clearance as gold standard in 702 children, we studied the diagnostic performance of 10 creatinine-based, 5 cystatin C-based and 3 combined cystatin C-creatinine eGFR equations and compared them to the result of the average of 9 pairs of a eGFRcystatin C and a eGFRcreatinine estimate. While creatinine-based GFR estimations are unsuitable in children unless calibrated in a pediatric or mixed pediatric-adult population, cystatin C-based estimations in general performed well in children. The average of a suitable creatinine-based and a cystatin C-based equation generally displayed a better diagnostic performance than estimates obtained by equations using only one of these analytes or by complex equations using both analytes. Comparing eGFRcystatin and eGFRcreatinine may help identify pediatric patients with Shrunken Pore Syndrome.
|
|
| 4. |
- Olafsson, Isleifur, et al.
(författare)
-
Production, characterization and use of monoclonal antibodies against the major extracellular human cysteine proteinase inhibitors cystatin C and kininogen
- 1988
-
Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 48:6, s. 573-582
-
Tidskriftsartikel (refereegranskat)abstract
- Murine monoclonal antibodies against the major cysteine proteinase inhibitors of human biological fluids, cystatin C and kininogen, were produced. The cystatin C antibody, HCC3, with a Ka of 2times107 l/mol, increased the inhibition of papain by cystatin C and was suitable for use in immunoblotting, immunohistochemistry and in the construction of a sensitive sandwich enzyme immunoassay for quantification of cystatin C. It recognized not only free cystatin C but also cystatin C in complexes with cysteine proteinases. The kininogen antibody, HK4, was directed against the third, cysteine proteinase inhibitory domain of the heavy chain of kininogen (Ka=1times107 l/mol), but did not influence the papain inhibitory activity of kininogen. It reacted with free kininogen as well as kininogen in complex with cysteine proteinases. Both antibodies could be used for the production of specific immunosorbents.
|
|
| 5. |
- Olafsson, I, et al.
(författare)
-
The aminoterminal portion of cerebrospinal fluid cystatin C in hereditary cystatin C amyloid angiopathy is not truncated. Direct sequence analysis from agarose gel electropherograms
- 1990
-
Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - 1502-7686. ; 50:1, s. 85-93
-
Tidskriftsartikel (refereegranskat)abstract
- The isolated amyloid substance in hereditary cystatin C amyloid angiopathy (HCCAA) is mainly composed of a cystatin C variant devoid of the 10 amino terminal amino acid residues of extracellular cystatin C from healthy individuals. We have developed a procedure for protein sequencing directly from agarose gel electropherograms and used this in conjunction with isoelectric focusing to investigate the amino terminal sequence of cerebrospinal fluid (CSF) cystatin C in HCCAA patients. The amino-terminal sequence determined for cystatin C from a HCCAA patient CSF sample, Xaa-Ser-Pro-Gly-Lys-Pro-Pro-Xaa-Leu-Val-Gly-Gly-Pro-Met-Xaa-Ala-Xaa-Val, showed that the protein was not amino-termi-nally truncated. CSF cystatin C from all nine HCCAA patients investigated was found to have an isoelectric point identical to that of native cystatin C, and the truncated form of cystatin C isolated from amyloid deposits was shown to contribute to less than 1 % of the total amount of cystatin C in CSF. The total cysteine proteinase inhibitory capacity of CSF from HCCAA patients was lower than that of CSF from other patients. This decreased CSF inhibitory capacity in HCCAA patients was caused by decreased levels of cystatin C, since the levels of the other two cysteine proteinase inhibitors found in CSF, oc2-macroglobulin and kininogen, were significantly higher than in CSF from non-HCCAA patients.
|
|
| 6. |
- Åkesson, Anna, et al.
(författare)
-
Shrunken pore syndrome and mortality : a cohort study of patients with measured GFR and known comorbidities
- 2020
-
Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 80:5, s. 412-422
-
Tidskriftsartikel (refereegranskat)abstract
- Shrunken pore syndrome (SPS) is defined by a cystatin C-based estimation of glomerular filtration rate (eGFRCYS) being less than 60% or 70% of a creatinine-based GFR estimation (eGFRCR) in the absence of extrarenal influences on cystatin C or creatinine concentrations. SPS has been associated with a substantial increase in mortality or morbidity in all investigated populations. However, in these studies, neither the diagnoses, nor causes of death were described, and only estimated GFR was available. The present study concerns 2781 individuals with measured GFR (mGFR), known diagnoses, and known causes of death during 5.6 years in median. Cox multivariate proportional hazards regression model was used to estimate hazard ratios (HR) for all-cause and cancer, cardiovascular, diabetes or chronic kidney disease (CKD) as cause-specific mortality among patients with SPS. At an eGFRCYS/eGFRCR-ratio <0.70, the adjusted SPS death risk in the total cohort (HR 3.0, 95% CI 2.4-3.7) was clearly higher than that for the other diagnosis groups. In a sub-cohort of 1300 persons with or without diagnosis, but with normal mGFR, the all-cause mortality of SPS was markedly increased (HR 4.1, 95% CI 2.6-6.5). In a sub-cohort of 567 persons with normal mGFR and no diagnosis, the all-cause mortality of SPS was even more increased (HR 7.3, 95% CI 2.3-23). The prevalence of SPS in the total cohort was 23% and in the sub-cohorts 17 and 12%, respectively. As SPS is associated with a high mortality, occurs in the absence of reduced mGFR and albuminuria, it expands the spectrum of kidney disorders.
|
|
