| 1. |
- Ahrén, B, et al.
(författare)
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Effects of minor increase in serum calcium on the immunoheterogeneity of parathyroid hormone in healthy subjects and in patients with primary hyperparathyroidism
- 1995
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Ingår i: Hormone Research. - 0301-0163. ; 43:6, s. 9-294
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Tidskriftsartikel (refereegranskat)abstract
- To study possible influences of a mild increase in serum-ionized calcium concentration that is seen during daily life on circulating parathyroid hormone (PTH) immunoheterogeneity, we used sequence-specific PTH assays to determine serum intact PTH, C-terminal PTH and N-terminal PTH following oral calcium (1.5 g) in healthy subjects (n = 7). This was also performed in patients with primary hyperparathyroidism (pHPT; n = 10) to see if their regulation of circulating PTH molecular forms is normal. Compared to healthy subjects, the patients were hypercalcemic (p < 0.05) and had higher levels of PTH in all three assays (p < 0.001). Following the oral calcium load, serum-ionized calcium increased by 0.08 +/- 0.03 mmol/l in the patients and by 0.07 +/- 0.03 mmol/l in the healthy subjects after 90 min, whereas serum intact PTH, C-terminal PTH and N-terminal PTH were reduced, both in the healthy subjects and in the patients. Suppression by calcium of both intact PTH and C-terminal PTH were impaired in the patients (p < 0.05 and p < 0.001), whereas suppression of N-terminal PTH was normal. Furthermore, the C/i and N/i ratios were higher at the highest calcium concentration achieved after calcium intake in the healthy subjects than in the basal state in the patients (p < 0.05), in spite of the larger degree of hypercalcemia in the latter (1.40 +/- 0.06 vs. 1.31 +/- 0.02 mmol/l; p < 0.05). Thus, (1) a minor increase in serum-ionized calcium that is seen during daily life alters the relative circulating concentrations of PTH versus its fragments; (2) the impaired sensitivity to calcium in pHPT is not evident for the suppression of N-terminal PTH, and (3) pHPT is accompanied by altered immunoheterogeneity of circulating PTH.
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| 2. |
- Becker, Charlotte, et al.
(författare)
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Individual prostate-specific antigen (PSA) forms as prostate tumor markers
- 1997
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Ingår i: Clinica Chimica Acta. - 0009-8981. ; 257:1, s. 117-132
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Tidskriftsartikel (refereegranskat)abstract
- Prostate-specific antigen (PSA) is a kallikrein-like serine protease mainly expressed in the human prostate. It is responsible for the proteolysis of the gel-forming proteins in human semen. Two major extracellular protease inhibitors, alpha-1-antichymotrypsin (ACT) and alpha-2-macroglobulin (AMG) may inactivate PSA escaping from the prostate. The predominant immunodetected form of PSA in serum is complexed to ACT but PSA exists also in a free non-complexed form despite the large excess of inhibitors. The concentrations of PSA in serum are normally less than 4 micrograms/l. but elevated concentrations are found in a majority of patients with prostate cancer (CAP) and the analysis of PSA in serum has become invaluable in the detection and monitoring of patients with CAP. However, it is not an ideal tumor marker in the sense that there are CAP patients with normal PSA concentrations in serum and patients with benign hyperplasia of the prostate (BPH) with elevated PSA concentrations. Analysis of the various PSA forms in serum attracts much interest as there is a higher proportion of PSA in complex with ACT in patients with CAP than in those with BPH. Optimal combinations of monoclonal antibodies have been used to design sensitive noncross-reacting immunoassays for the detection of free PSA, PSA-ACT complexes and the detection of both free PSA and PSA complexes in an equimolar fashion (i.e. total PSA). Several studies have demonstrated that the analysis of the proportions of the free-to-total PSA in serum may increase the diagnostic specificity by 15-20% without significant loss in the sensitivity for detection of CAP.
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| 3. |
- Elneihoum, A. M., et al.
(författare)
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Leukocyte activation detected by increased plasma levels of inflammatory mediators in patients with ischemic cerebrovascular diseases
- 1996
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Ingår i: Stroke: a journal of cerebral circulation. - 0039-2499. ; 27:10, s. 1734-1738
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose: Leukocytes have been implicated in the development of ischemia atherosclerotic vascular disease. In a prospective study we investigated whether the plasma concentration of inflammatory mediator, ie, proteases and cytokine, as markers for systemic leukocyte activation, are increased in patient with acute ischemic cerebrovascular diseases. Methods: Using enzyme-linked immunosorbent assays, we measured the plasma level of neutrophil gelatinase-associated lipocalin (NGAL), neutrophil proteinase 4 (NP4), tumor necrosis factor-α (TNF)m and soluble TNF receptor protein-1 p55 (sTNFR-1) in 120 patients with acute ischemic cerebrovascular insult (72 with and 48 stroke and 48 with transient ischemic attack (TIAl) and in 35 age-and sex-matched healthy subject. Results: Compared with the control group, plasma NGAL levels were higher in the stroke group (P<.0001) and the TIA group (P<.01); plasma NP4 levels were higher in the stroke group (P<.0001) and the TIA group (P<.01); and plasma sTNFR-1 levels wee higher in the stroke group (P<.04). There was significant correlation between the plasma levels of fibrinogen and those of both sTNFR-1 (r=.32; P=32; P=.005) and NGAL 9r=.40; P=.0001) and between the erythrocyte sedimentation rate and the plasma levels of both sTNFR-1 (r=.35; P=.001) and NGAL (r=.34;P=.002). Conclusions: Our study demonstrated that marker for systemic leukocyte activation, ie, plasma levels of cytokine and protease, were higher in patients with acute ischemic cerebrovascular disease than in healthy control subject. Activated leukocytes and leukocytic mediator may have an important role in acute cerebrovascular ischemia and it consequences.
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| 4. |
- Hultberg, Björn, et al.
(författare)
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Concentrations of plasma methylmalonic acid in 80-year-olds show only weak relation to psychological performance
- 1999
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Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621. ; 37:10, s. 963-967
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Tidskriftsartikel (refereegranskat)abstract
- Most studies of the relation between psychological performance in the elderly and deficiencies of cobalamin and folate have used methods that determine the blood concentrations of these vitamins, which might not reflect the vitamin status in the tissues. Recently, two new markers, plasma homocysteine and methylmalonic acid, have attracted growing interest since they are considered to reflect the status of cobalamins and folates in the tissues. In a previous study, we noted a strong association between five parameters of well-being and lower concentrations of plasma homocysteine. In the present study, we have extended these observations by determination of plasma methylmalonic acid in the same healthy elderly population. In the present study, 18 out of 100 subjects had increased plasma methylmalonic acid and in 7 of these subjects, the concentrations of serum cobalamin, blood folate, plasma homocysteine and serum creatinine were within normal limits. The relation between plasma methylmalonic acid concentrations and concentrations of serum cobalamin and blood folates and five parameters of well-being were investigated. Concentrations of plasma methylmalonic acid were only weakly associated with the concentrations of serum cobalamin and lower scores on the logical reasoning test. The present study clearly shows that the levels of plasma methylmalonic acid show a much lesser association with the parameters of well-being than did plasma homocysteine.
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| 5. |
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