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K Pettersson

Publications and source records attributed to K Pettersson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Cross-talk between ERs and signal transducer and activator of transcription 5 is E2 dependent and involves two functionally separate mechanisms.

Steroid hormone receptors and signal transducers and activators of transcription (STAT) factors constitute two distinct families of transcription factors activated by different signaling pathways. In previous reports, cross-talk between STAT5 and several steroid receptors has been demonstrated. We investigated putative cross-talk between ERalpha and ERbeta and STAT5. ERalpha and ERbeta were found to potently repress PRL-induced STAT5 transcriptional activity on a beta-casein promoter construct in a ligand-dependent manner. This down-regulation was found to rely on direct physical interaction between the ERs and STAT5, mediated via the ER DNA-binding domain (DBD). The contact between the ER DBD and STAT5 is highly specific; the interaction is abolished if the ERalpha DBD is replaced with the DBD of a closely related steroid receptor. The physical interaction, however, is insufficient to confer the repression of STAT5 activity, which in addition requires the ligand-activated C-terminal part of the ERs, although these domains are not in direct contact with STAT5. Negative cross-talk between ERs and STAT5 is thus mediated via several functionally separated domains of the ERs. Our findings may enhance the understanding of mechanisms of regulation of the different hormonal signaling pathways occurring during different functional events in tissues coexpressing ERs and STAT5.

Animals↗
PubMed2001

Immunological characterization of human luteinizing hormone with special regard to a common genetic variant.

Immunoassays are widely used for measuring gonadotropins, including luteinizing hormone (LH), as these are both specific and sensitive. Because LH is microheterogeneous it has been claimed that the specificity of monoclonal antibodies used in two-site immunoassays can limit their clinical utility. Furthermore, we reported earlier a common genetic variant form of LH due to amino acid alterations in the LHbeta gene that is poorly or not recognized by antibodies directed against epitopes present in the intact molecule. We here report the result of an LH epitope mapping using 30 different monoclonal antibodies. The antigenic area affected by the amino acid alterations is fairly large, as antibodies to the two intact domains are able to sandwich each other. Combinations of alpha-beta or beta-beta antibodies generally provide alternatives for unbiased detection of circulating LH and some have reasonably good discrimination of human chorionic gonadotropin. The beta-beta combinations exhibit a peculiarity in urine determinations as they detect the urinary beta-core fragment. Our aims were to study the altered immunoreactivity caused by the amino acid changes and to design two-site LH assays fully capable of recognizing the biologically active LH variant. We also conclude that the variability in recognizing the universally occurring LH variant is the most important factor contributing to the widely documented LH immunoassay discrepancies.

Antibodies, Monoclonal↗
PubMed2001

Measurement of circulating forms of prostate-specific antigen in whole blood immediately after venipuncture: implications for point-of-care testing.

BACKGROUND: The purpose of this study was to validate the use of whole-blood samples in the determination of circulating forms of prostate-specific antigen (PSA). METHODS: Blood samples of hospitalized prostate cancer and benign prostatic hyperplasia patients were collected and processed to generate whole-blood and serum samples. Three different rapid two-site immunoassays were developed to measure the concentrations of total PSA (PSA-T), free PSA (PSA-F), and PSA-alpha(1)-antichymotrypsin complex (PSA-ACT) to detect in vitro changes in whole-blood samples immediately after venipuncture. The possible influence of muscle movement on the release of PSA from prostate gland was studied in healthy men by measuring the rapid in vitro whole-blood kinetics of PSA forms before and after 15 min of physical exercise on a stationary bicycle. RESULTS: Rapid PSA-T, PSA-F, and PSA-ACT assays were designed using a 10-min sample incubation. No significant changes were detected in the concentrations of PSA-T, PSA-F, and PSA-ACT from the earliest time point of 12-16 min compared with measurements performed up to 4 h after venipuncture. Physical exercise did not influence the concentrations of the circulating forms of PSA. Hematocrit-corrected whole-blood values of PSA-T and PSA-F forms were comparable to the respective serum values. Calculation of the percentage of PSA-F (PSA F/T ratio x 100) was similar irrespective of the sample format used, i.e., whole blood or serum. CONCLUSIONS: We found that immunodetectable PSA forms are likely at steady state immediately after venipuncture, thus enabling the use of anticoagulated whole-blood samples in near-patient settings for point-of-care testing, whereas determinations of PSA (e.g., PSA-T, PSA-F, or PSA-ACT) performed within the time frame of the office visit would provide results equivalent to conventional analyses performed in serum.

Blood Specimen Collection↗
PubMed2001

Discrimination of prostate cancer from benign disease by plasma measurement of intact, free prostate-specific antigen lacking an internal cleavage site at Lys145-Lys146.

BACKGROUND: The proportion of free prostate-specific antigen (PSA) is higher in the sera of patients with benign prostatic hyperplasia compared with patients with prostate cancer (PCa). We developed an immunoassay that measures intact, free PSA forms (fPSA-I), but does not detect free PSA that has been internally cleaved at Lys145-Lys146 (fPSA-N), and investigated whether this form could discriminate patients with PCa from those without PCa. METHODS: The assay for fPSA-I uses a novel monoclonal antibody (MAb) that does not detect PSA that has been internally cleaved at Lys145-Lys146. A MAb specific for free PSA was used as a capture antibody, and purified recombinant proPSA was used as a calibrator. The concentrations of fPSA-I, free PSA (PSA-F), and total PSA (PSA-T) were analyzed in EDTA-plasma samples (n = 276) from patients who participated in a screening program for PCa (PSA-T, 0.83-76.3 microg/L). RESULTS: The detection limit of the fPSA-I assay was 0.035 microg/L. Both the measured concentrations of fPSA-I and the concentrations of fPSA-N (calculated as PSA-F - fPSA-I) provided statistically significant discrimination of the two clinical groups. By contrast, PSA-F did not discriminate between these groups. Each of the ratios fPSA-I/PSA-F, fPSA-N/PSA-T, and PSA-F/PSA-T separated cancer samples from noncancer samples in a statistically significant manner (P <0.0001). The ratio fPSA-I/PSA-F was significantly higher in cancer (median, 59%) compared with noncancer samples (47%). CONCLUSIONS: The ratio fPSA-I/PSA-F is significantly higher in cancer compared with noncancer. The percentages of both fPSA-N/PSA-T and fPSA-I/PSA-F may provide interesting diagnostic enhancements alone or in combination with other markers and require further studies.

Aged↗
PubMed2001

N,N'-diacetyl-L-cystine (DiNAC), the disulphide dimer of N-acetylcysteine, inhibits atherosclerosis in WHHL rabbits: evidence for immunomodulatory agents as a new approach to prevent atherosclerosis.

Oxidation of lipoprotein-derived lipids is generally accepted to be important in atherogenesis, and lipophilic antioxidants have been suggested as potential antiatherosclerotic agents. The antiatherogenic effects observed by certain antioxidants, especially probucol, in different animal models support this suggestion. There are however also cases where other lipophilic antioxidants have not been able to support this hypothesis. This has raised the question whether the effects of probucol and similar compounds are mainly due to some other property, unrelated to their antioxidant efficacy. For example, probucol is shown to possess immunomodulatory properties. Immune reactions are known to occur during atherogenesis. We therefore tested the dimer of N-acetylcysteine, DiNAC, which is a disulfide with immunomodulating properties and enhances oxazolone-induced contact sensitivity (CS) reactions in mice, for effects on atherosclerosis. When given to male heritable hyperlipidemic rabbit (WHHL) rabbits from 10 to 22 weeks of age, this compound reduced by 50% thoracic aorta atherosclerosis (p < 0.05), without affecting plasma lipid levels. Here we also show that probucol and a close chemical analog, both known to prevent atherosclerosis in WHHL rabbits, enhance the CS reaction in mice, while two other related antioxidants did not affect the CS reaction. At least one of these is also without effect on atherosclerosis in WHHL rabbits. The results show that DiNAC might represent a new treatment modality for atherosclerosis-related disease, and suggest that some antioxidants may have antiatherosclerotic properties more related to "immunomodulatory" properties than to antioxidant properties in general.

Acetylcysteine↗
PubMed2000

Estrogen receptor beta acts as a dominant regulator of estrogen signaling.

The physiological effects of estrogens are mediated by two intracellular transcription factors, the estrogen receptors (ERs), that regulate transcription of target genes through binding to specific DNA target sequences. Here we describe alterations in cellular responses to different ER agonists and to the anti-estrogenic compound tamoxifen resulting from co-expression of the two ERs in transient co-transfection experiments. Our results demonstrate that ERbeta can act as a negative or positive dominant regulator of ER activity. This is manifested through reduced transcriptional activity at low concentrations of estradiol (E2); increased antagonistic effects of tamoxifen on E2 stimulated activity; and enhanced agonistic action of the phytoestrogenic compound genistein. Furthermore, using chimeric proteins lacking the N-terminal activation function 1 (AF-1), we show that the differential responses of ERalpha and ERbeta to different agonists and antagonists are primarily dictated by inherent differences in the C-terminal ligand-binding domains of the receptors, whereas the magnitude of transcriptional activity is influenced by ERalpha AF-1, but not ERbeta AF-1. The ERalpha AF-1 activity appears to be modulated upon co-expression of both ERs. The alterations in transcriptional activity resulting from co-expression of ERalpha and ERbeta are probably due to the formation of alpha/beta heterodimeric complexes. This study demonstrates that co-localization and subsequent heterodimerization of ERalpha and ERbeta may result in receptor activity distinct from that of ER homodimers.

Cell Line↗
PubMed2000

Time-resolved fluorescence imaging for specific and quantitative immunodetection of human kallikrein 2 and prostate-specific antigen in prostatic tissue sections.

OBJECTIVES: To design protocols for specific and quantitative immunohistochemical detection of human kallikrein 2 (hK2) using lanthanide chelate-labeled monoclonal antibodies (Mabs) and time-resolved fluorescence imaging. METHODS: Anti-prostate-specific antigen (PSA) Mabs were tested in microtiterplate assays for their ability to prevent PSA from cross-reacting with the anti-hK2 Mab 6H10. Europium-labeled 6H10 and terbium-labeled anti-PSA Mab 2E9, selected as the best blocker antibody, were used for dual-label immunodetection in routinely fixed benign (n = 7) and malignant (n = 5) prostate specimens. The amounts of IgG bound in tissue were calculated from drops containing known Mab concentrations. RESULTS: The use of anti-PSA Mab 2E9 for blocking diminished the cross-reaction from 5% to 0.3%. In the analyzed tissues, there was considerable variation in staining intensity for both proteins; PSA signals varied from 0.1 to 36.6 times that of hK2, with on average 10-fold more bound anti-PSA Mab than anti-hK2 Mab. In malignant tissue, the amounts of bound IgGs were lower and more variable than in benign tissue using both the anti-PSA Mab and the anti-hK2 Mab. The variation in signal intensities for PSA and hK2 correlated significantly in benign tissue (P >0.05), but not in benign hyperplastic and malignant specimens (P <0.05). CONCLUSIONS: Quantification of two lanthanide chelate-labeled antibodies bound in the same tissue section enabled comparison of PSA and hK2 content in individual cells. The average cellular content of hK2 relative to that of PSA was consistent with previous mRNA studies. The time-resolved fluorescence imaging-based quantification method has universal applicability in fixed tissue specimens.

Antibodies, Monoclonal↗
PubMed2000

Level of circulating phospholipase A2 in prediction of the prognosis of patients with suspected myocardial infarction.

OBJECTIVES: Atherosclerotic lesions result from inflammatory-proliferative responses of the endothelium and smooth muscle of the arterial wall. Poor prognosis of acute myocardial infarction (AMI) patients has been associated with elevated levels of acute phase proteins including C-reactive protein. We investigated the significance of circulating phospholipase A2 in the long-term prognosis of suspected AMI patients. METHODS: The concentration of phospholipase A2 was measured by an immunoassay in sera of 100 suspected AMI patients. Admission phospholipase A2 95 % fractile outliers were excluded to eliminate the effect of acute infectious diseases. The total and atherosclerotic mortalities were followed for a 4-year period. RESULTS: The most powerful prognostic limit for both admission (p = 0.02, RR = 2.6 and 95% CI = 1.2 to 5.6) and maximal (p = 0.06, RR = 2.4 and 95% CI = 0.96 to 5.9) phospholipase A2 groups was > or =8 microg/l. The admission phospholipase A2 level had an independent prognostic significance for atherosclerotic mortality (p = 0.04, RR = 2.4 and CI = 1.02 to 5.8) in multivariate analysis with CK-MB and age. CONCLUSIONS: The elevated serum phospholipase A2 level at admission is an independent predictor of long-term atherosclerotic mortality in patients with suspected AMI. The prognostic significance of phospholipase A2 weakens during hospitalisation concomitant to the onset of the acute inflammatory response to myocardial injury.

Aged↗
PubMed2000

Cardiac decompensation during an ischemic event weakens the predictive power of myocardial injury markers.

Our objection was to find determinants of long-term outcome in routine data collected for differential diagnosis of suspected acute myocardial infarction. Study population consisted of 263 discharged patients who were initially hospitalized for differential diagnosis of suspected acute myocardial infarction between October 1992 and January 1993. Follow-up time for all cause and cardiac mortality was 5 years. The variables studied as predictors of outcome were computerized ECG, peak creatine kinase isoenzyme MB, peak troponin I, radiographic evidence of pulmonary congestion (cardiac decompensation), treatment for hyperlipidemia, hypertension or diabetes, smoking, previous myocardial infarction, age and gender. Total mortality was 32% at 5 years, of which 77% (64/83) was of cardiac origin. Pulmonary congestion in chest X-ray was the most powerful predictor of outcome (RR=3.3, 95% CI=2.0-5.2, P<0.001). In multivariate analysis congestion (RR=3.3, CI=2.0-5.2) was the only independent predictor of 5-year total mortality in addition to age (RR=1.06, CI=1.04-1.08). These two variables together with previous myocardial infarction (RR=1.9, CI=1.2-3.1) and hyperlipidemia (RR=2. 0, CI=1.1-3.5) were independent predictors of cardiac mortality. Radiographic evidence of cardiac decompensation during hospitalization is a strong and independent predictor of long-term outcome in unselected patients with suspected AMI. The predictive power of cardiac markers is confined to patients without pulmonary congestion.

Aged↗
PubMed2000

Clinical value of human glandular kallikrein 2 and free and total prostate-specific antigen in serum from a population of men with prostate-specific antigen levels 3.0 ng/mL or greater.

OBJECTIVES: To investigate the clinical value of human glandular kallikrein 2 (hK2) compared with free (f) and total (t) prostate-specific antigen (PSA) in the early detection of prostate cancer (PCa). METHODS: In PCa screening conducted in 1995 to 1996 in Göteborg, Sweden, 5853 of 9811 randomly selected men (aged 50 to 66 years; median 61) accepted PSA testing; those with tPSA levels of 3. 0 ng/mL or greater were offered digital rectal examination, transrectal ultrasound, and sextant biopsies. Serum from 604 of 611 biopsied men (18% with positive digital rectal examinations, tPSA range 3.0 to 220 ng/mL, 144 men with PCa) was analyzed for hK2 (research assay) and tPSA and fPSA (Prostatus). Sera were stored at -20 degrees C for a maximum of 2 weeks for tPSA and fPSA and 3 years for hK2. RESULTS: hK2 levels and hK2 x tPSA/fPSA values were significantly elevated in men with PCa. Receiver operating characteristic data revealed that the area under the curve for hK2 x tPSA/fPSA was significantly greater than that for tPSA and greater, but not significantly greater, than that for percent fPSA. Also, the cancer-detecting sensitivity was significantly improved (P <0.05) using hK2 x tPSA/fPSA compared with tPSA and percent fPSA at specificity levels of 75% to 90%. At 75% specificity, a sensitivity of 74% was obtained compared with 64% or 54% using percent fPSA or tPSA; at 90% specificity, the corresponding sensitivity level was 55%, 41%, and 36%, respectively. CONCLUSIONS: Discrimination of men with and without PCa in a randomly selected population was improved by measuring hK2 in addition to tPSA and fPSA.

Aged↗
PubMed2000

Human glandular kallikrein as a tool to improve discrimination of poorly differentiated and non-organ-confined prostate cancer compared with prostate-specific antigen.

OBJECTIVES: Human glandular kallikrein (hK2) possesses 80% structure identity with prostate-specific antigen (PSA) and is secreted by identical prostate epithelial cells. Although increasing with pathologic stage, PSA is not clinically sufficient to predict histologic grade and pathologic stage of prostate cancer (PCa) in individual cases. To address this issue, serum hK2 in various PCa grades was investigated. METHODS: Sera from 122 consecutive patients with PCa, graded as well-differentiated (G1, n = 35); moderately differentiated (G2, n = 61), and poorly differentiated (G3, n = 26) PCa, was studied. In patients who underwent radical prostatectomy (n = 42), 24 had organ-confined (pT2a-b) and 18 extracapsular (pT3a or greater) disease. hK2 was measured by an indirect immunofluorometric assay with a functional sensitivity of 0.03 ng/mL. Total PSA (tPSA), free PSA (fPSA), and PSA bound to alpha(1)-antichymotrypsin (PSA-ACT) were also measured. Multivariate logistic regression analysis was used for evaluation of the best combinations of tumor markers. RESULTS: Median hK2 and tPSA increased twofold from G1 to G2 tumors (hK2 0.07 versus 0.14 ng/mL, P <0.002; tPSA 6.1 versus 12.1 ng/mL, P <0.0002). Between G2 and G3 tumors, hK2 increased threefold (0.14 versus 0.43 ng/mL, P <0.02), and tPSA showed no significant increase (12.1 versus 26.5 ng/mL, P <0.18). The f/t PSA ratio decreased between G1 and G2 cancers (0.15 vs. 010, P <0.001); no difference was found between G2 and G3 tumors (0.10 versus 0.11, P = 0.93). However, the hK2/fPSA ratio distinguished between G1 and G3 tumors and G2 and G3 tumors (0.085 [G1] and 0.11 [G2] versus 0.22 [G3], P <0.0002 and P <0.002, respectively). Using multivariate regression analysis, the fPSA/(tPSA x hK2) ratio differentiated G2 and G3 tumors (P <0.01). In the tPSA range of 3 to 15 ng/mL, hK2, the hK2/fPSA ratio, and the fPSA/(tPSA x hK2) ratio differentiated between the G1/G2 and G3 tumors, and tPSA, the f/t PSA ratio, and PSA-ACT did not. In radical prostatectomy cases, hK2 (0.06 versus 0. 156, P <0.005) and the fPSA/(tPSA x hK2) ratio (2.104 versus 0.828, P <0.005) discriminated between pT2a-b and pT3a or greater PCa. CONCLUSIONS: hK2 significantly improved the identification of poorly differentiated (G3) tumors compared with PSA. By multivariate logistic regression analysis, the hK2/fPSA and fPSA/(tPSA x hK2) ratios further improved the detection of PCa grade. This improvement was also seen with the intermediate range of tPSA. hK2 was also helpful in the prediction of organ-confined disease. Thus, hK2 may be a useful tool for more accurate prediction of tumor grade or stage and allow better clinical decision-making.

Aged↗
PubMed2000

Anti-atherogenic effect of coenzyme Q10 in apolipoprotein E gene knockout mice.

Oxidation of low-density lipoprotein (LDL) lipid is implicated in atherogenesis and certain antioxidants inhibit atherosclerosis. Ubiquinol-10 (CoQ10H2) inhibits LDL lipid peroxidation in vitro although it is not known whether such activity occurs in vivo, and, if so, whether this is anti-atherogenic. We therefore tested the effect of ubiquinone-10 (CoQ10) supplemented at 1% (w/w) on aortic lipoprotein lipid peroxidation and atherosclerosis in apolipoprotein E-deficient (apoE-/-) mice fed a high-fat diet. Hydroperoxides of cholesteryl esters and triacylglycerols (together referred to as LOOH) and their corresponding alcohols were used as the marker for lipoprotein lipid oxidation. Atherosclerosis was assessed by morphometry at the aortic root, proximal and distal arch, and the descending thoracic and abdominal aorta. Compared to controls, CoQ10-treatment increased plasma coenzyme Q, ascorbate, and the CoQ10H2:CoQ10 + CoQ10H2 ratio, decreased plasma alpha-tocopherol (alpha-TOH), and had no effect on cholesterol and cholesterylester alcohols (CE-OH). Plasma from CoQ10-supplemented mice was more resistant to ex vivo lipid peroxidation. CoQ10 treatment increased aortic coenzyme Q and alpha-TOH and decreased the absolute concentration of LOOH, whereas tissue cholesterol, cholesteryl esters, CE-OH, and LOOH expressed per bisallylic hydrogen-containing lipids were not significantly different. CoQ10-treatment significantly decreased lesion size in the aortic root and the ascending and the descending aorta. Together these data show that CoQ10 decreases the absolute concentration of aortic LOOH and atherosclerosis in apoE-/- mice.

Animals↗
PubMed2000

Functional differences between the amino-terminal domains of estrogen receptors alpha and beta.

Human estrogen receptors alpha (ERalpha) and beta (ERbeta) are ligand-inducible transcription factors that are highly homologous in their central DNA-binding and carboxyl-terminal ligand-binding domains. In contrast, there is very little conservation between ERalpha and ERbeta in the amino-terminal domain. Using different human cell lines, we show that wild-type ERbeta transcriptional activity is lower or similar to that of ERalpha, depending on the cell type. Deletion of the amino-terminal domain in both ER subtypes resulted in no or a lower decrease of transcriptional activity of ERbeta compared with ERalpha, suggesting that the ERbeta amino-terminal domain contains a weaker transcriptional activation function-1. Using ERalpha and ERbeta deletion mutants, we showed that the amino-terminal transcriptional activity of ERbeta maps to amino acids 1-31. Interestingly, this domain contains a six amino-acid motif (amino acids 5-10 in human ERbeta) that is part of the ERalpha-activation function-1 region (amino acids 49-54 in human ERalpha) and highly conserved among all mammalian ERalpha amino-terminal domains. Despite this similarity between the two ER subtypes, no autonomous and ligand-independent activity of the ERbeta-amino-terminal domain was observed in yeast and mammalian cells in contrast to ERalpha. This study provides a molecular basis for the difference in transcriptional activity between ERalpha and ERbeta and establishes that ERbeta contains a structurally and functionally restricted amino-terminal transcriptional activity.

Cells, Cultured↗
PubMed2000

Site-specific antiatherogenic effect of probucol in apolipoprotein E-deficient mice

-The lipid-lowering antioxidant probucol can inhibit atherosclerosis in animals and restenosis in humans. However, probucol has been shown to promote atherosclerosis in the aortic root of apolipoprotein E-deficient (apoE-/-) mice. In the current study, we examined the effects of probucol on both lesion formation at 4 sites along the aorta and lipoprotein oxidation in the plasma and aortas of apoE-/- mice receiving a diet containing 21.2% (wt/wt) fat and 0. 15% (wt/wt) cholesterol without or with 1% (wt/wt) probucol. After 6 months, controls had developed lesions at all sites investigated. Lesion development was strongly (P=0.0001) affected by probucol, but this effect was not uniform: lesion size was increased in the aortic root but significantly decreased in the arch, the descending thoracic aorta, and proximal abdominal aorta. Plasma and aortas of probucol-treated mice contained high concentrations of probucol and its metabolites (bisphenol and diphenoquinone); increased vitamin C; markedly decreased very low density lipoprotein (but not low density lipoprotein and high density lipoprotein); and decreased cholesterol, cholesteryl esters, triglycerides, vitamin E, and oxidized lipids compared with controls. Interestingly, probucol treatment did not decrease the proportion of aortic lipids that were oxidized. Plasma vitamin C and bisphenol, but not probucol, protected plasma lipids from ex vivo oxidation by peroxyl radicals. These results show that as in other species, probucol can inhibit lesion formation in most parts of the aorta of apoE-/- mice. This effect may involve lipid oxidation-independent mechanisms localized within the vessel wall as well as lipid lowering.

Journal Article↗
PubMed2000

Strong prediction of fractures among older adults by the ratio of carboxylated to total serum osteocalcin.

We examined serum total osteocalcin (TOC), carboxylated osteocalcin (COC), and their ratio (COC/TOC) by one-step two-site immunofluorescent assays in 87% (n = 792) of all home-dwelling persons of 70 years or older living in a defined area in northern Finland. Other baseline subject-related risk factors of fractures were assessed by postal questionnaires, interviews, clinical examinations, and tests. During a 5-year follow-up period, all falls and fractures (n = 106) were recorded by regular phone calls and by examining all the medical records yearly. Serum TOC and COC concentrations increased with advancing age and were higher in women than in men, but corresponding differences were not found in the case of COC/TOC. The adjusted relative risk of fracture was elevated in association with low (< or =-1 SD from the mean) COC; hazard ratio (HR, 95% CI) 2.00 (1.20-3.36) and low COC/TOC; HR 5.32 (3.26-8.68), the relative risk being highest in the population older than 80 years; and HR 7.02 (2.42-20.39). The predictive value of low COC/TOC lasted 3 years. The multivariable-adjusted relative risk of hip fracture (n = 26) in regard to low COC/TOC ratio was 3.49 (1.12-10.86), as compared with the persons who did not suffer hip fractures. Our results suggest that serum COC concentrations and, more strongly, COC/TOC, predict the occurrence of fractures in older community-dwelling adults. The risk of fracture associated with low COC/TOC equals the hip fracture risk previously verified for concomitant high serum undercarboxylated OC concentrations and low bone mineral density.

Aged↗
PubMed2000

Discrimination of men with prostate cancer from those with benign disease by measurements of human glandular kallikrein 2 (HK2) in serum.

PURPOSE: To investigate the clinical value of measuring human glandular kallikrein 2 (hK2) compared with free and total prostate specific antigen (PSA-F and PSA-T) in serum from patients with prostate disease. MATERIALS AND METHODS: Serum from healthy controls, from men with benign prostate hyperplasia (BPH), clinically localized prostate cancer (PCa), and advanced PCa were analyzed for hK2 (using an in-house-research assay with detection limit of 0.05 ng./mL and <0.1% cross-reaction with PSA) and for PSA-F and PSA-T (using the Dual Prostatus assay from EG&G Wallac). RESULTS: HK2 concentrations were <0.05 ng./mL in 50/50 healthy volunteers but significantly higher (p <0.0001) and > or =0.05 ng./mL in 28/54 (52%) patients with BPH. In comparison to these men, the hK2 levels were significantly higher (p <0.0001, median 0.085 ng./mL) and > or =0.05 ng./mL in 100/136 (74%) men with clinically localized PCa. Compared with localized PCa, the hK2 levels were significantly higher (p <0.0001, median 0.57 ng./mL) and > or =0.05 ng./mL in 55/57 (96%) patients with advanced PCa. The median hK2 levels ranged from 1.3 to 1.6% of those of PSA-T in all three patient groups, whereas percent hK2/PSA-F and hK2 x PSA-T/PSA-F levels were significantly higher in cancer patients compared with those with BPH. In the discrimination of clinically localized PCa from BPH, hK2 x PSA-T/PSA-F gave the largest area under the receiver operating curve (AUC = 0.81) and significantly (p = 0.025) larger AUC than PSA-T alone (0.70). Further, at 95% sensitivity there was significant gain in specificity, and at specificity levels of 90 to 95% there was significant gain in sensitivity using the measurements of PSA-T+PSA-F+hK2 compared with analysis of PSA-T and/or percent free PSA. CONCLUSIONS: Discrimination of patients with benign prostate disease from those with prostate cancer was significantly enhanced using measurements of hK2 in addition to those of PSA-T and PSA-F. Percent hK2/PSA-F was higher in PCa than in BPH, a phenomena not yet understood.

Adult↗
PubMed2000

Sensitive and specific immunodetection of human glandular kallikrein 2 in serum.

BACKGROUND: Human glandular kallikrein 2 (hK2) is expressed in the prostate and is present in serum from men with prostate cancer. Specific detection in serum is difficult mainly because of low concentrations and immunological cross-reactivity with prostate-specific antigen (PSA). Our objectives were to design an assay with improved analytical detection and functional sensitivity and nonsignificant cross-reactivity with PSA, and to characterize different immunoreactive forms of hK2. METHODS: In the assay, critical PSA epitopes were blocked with four monoclonal antibodies (MAbs) specific for PSA. Subsequently, hK2 was captured using a MAb against hK2 (5% cross-reactivity with PSA), and after washing, hK2 was detected by a europium-labeled MAb with identical affinity for hK2 and PSA. RESULTS: The analytical detection limit was <10 ng/L, and functional sensitivity was 30 ng/L. Cross-reaction with PSA was <0.01%. Between-assay imprecision was 3.1% for 1600 ng/L hK2 and 4. 8% for 160 ng/L hK2; corresponding values for within-assay precision were 1.9% and 4.5%, respectively. Complexes of hK2-alpha(1)-antichymotrypsin (ACT) were detected in vitro with -6% bias compared with the free form of hK2. Gel filtration of patient samples showed that hK2 correlated in size mainly with free hK2; only 4-19% corresponded to hK2 possibly complexed with ACT or protein C inhibitor. CONCLUSIONS: Our assay had extremely low cross-reactivity with PSA, provided a very low detection limit, and allowed close to equimolar detection of the free and complexed forms of hK2. Moreover, we found that free hK2 is the predominant immunoreactive form of hK2 in serum.

Adolescent↗