Biomedical subjects

Roland Einarsson

Publications and source records attributed to Roland Einarsson.

6 recordsLinked to original sources

PubMed2004

Sensitive nonradiometric method for determining thymidine kinase 1 activity.

BACKGROUND: Thymidine kinase 1 (TK1) is a cytoplasmic enzyme, produced only in the S-phase of proliferating cells, that has potential as a tumor marker. Specific determination of TK1 in serum is difficult, in part because of differences in the physical properties of serum TK1 compared with cytoplasmic TK1. METHODS: The first step in the new assay was phosphorylation of 3'-azido-2',3'-deoxythymidine (AZT) to AZT 5'-monophosphate (AZTMP) by TK1 present in patient material. The AZTMP formed was measured in a competitive immunoassay with specific anti-AZTMP antibodies and AZTMP-labeled peroxidase. Results were compared with those of a TK radioenzyme assay (REA) for 78 samples from patients suffering from hematologic diseases. RESULTS: The detection limit was 78 microIU/L, and within-run CVs <20% were seen for samples with TK1 down to 130 microIU/L. Cross-determination of the mitochondrial isoenzyme TK2 activity was <0.1%. Between-assay imprecision (CV) was 3.5-7.4%, and the within-assay imprecision was 4.1-9.1%. In studies of recovery and linearity on dilution, measured values ranged from 84% to 115% of expected at concentrations of 0.26-10.4 mIU/L. Results of the new assay (mIU/L) = 0.109 x TK REA (U/L) + 0.092. Heterophilic antibodies did not interfere in the assay. The upper 95th percentile, in 100 healthy individuals, was 0.94 mIU/L, and the median value was 0.43 mIU/L. CONCLUSION: The TK1 enzyme-labeled immunoassay uses a stable substrate, is precise, appears to be accurate, and is resistant to interferences. It may provide a practical tool in the management of hematologic malignancies.

Biomarkers, Tumor↗

PubMed2004

Clinical utility of cytokeratins as tumor markers.

Cytokeratins, belonging to the intermediate filament (IF) protein family, are particularly useful tools in oncology diagnostics. At present, more than 20 different cytokeratins have been identified, of which cytokeratins 8, 18, and 19 are the most abundant in simple epithelial cells. Upon release from proliferating or apoptotic cells, cytokeratins provide useful markers for epithelial malignancies, distinctly reflecting ongoing cell activity. It appears that motifs in certain cytokeratins make them likely substrates for caspase degradation, and their subsequent release occurs during the intermediate events in apoptosis. The clinical value of determining soluble cytokeratin protein fragments in body fluids lies in the early detection of recurrence and the fast assessment of the efficacy of therapy response in epithelial cell carcinomas. The three most applied cytokeratin markers used in the clinic are tissue polypeptide antigen (TPA), tissue polypeptide specific antigen (TPS), and CYFRA 21-1. TPA is a broad spectrum test that measures cytokeratins 8, 18, and 19. TPS and CYFRA 21-1 assays are more specific and measure cytokeratin 18 and cytokeratin 19, respectively. By following patients with repeated testing during management, the oncologist may obtain critical information regarding the growth activity in symptomatic patients. Although their main use is to monitor treatment and evaluate response to therapy, early prognostic information particularly on tumor progression and metastasis formation is also provided for several types of cancers. Cytokeratin tumor markers can accurately predict disease status before conventional methods and offer a simple, noninvasive, cheap, and reliable tool for more efficient management.

Antigens, Neoplasm↗

PubMed2004

S100 proteins as cancer biomarkers with focus on S100B in malignant melanoma.

Although histochemical staining of the S100 protein family has been used for many years in the diagnosis of malignant melanoma, recent studies suggest one of the proteins comprising the S100 family, S100B, has particular utility in many aspects of the clinical management of malignant melanoma. This protein has been shown to be of use in staging malignant melanoma, in establishing prognosis, in evaluating treatment success and in predicting relapse. S100B is an independent prognostic factor and pretreatment circulating S100B concentrations predict duration of survival in melanoma patients. Survival is significantly longer in melanoma patients with normal S100B levels compared to those with elevated levels. Circulating S100B levels very sensitively detect metastatic growth of malignant melanoma, particularly in stage IV disease where S100B is certainly superior to other laboratory parameters. S100B concentrations reflect tumor mass. Serum S100B levels predict efficacy of treatment. Decreasing S100B concentrations reflect response to therapy while increasing S100B concentrations indicate tumor progression. Circulating S100B has a role to play in the decision to switch treatment regimens.

Biomarkers, Tumor↗

PubMed2002

Comparative analysis of CA125, tissue polypeptide specific antigen, and soluble interleukin-2 receptor alpha levels in sera, cyst, and ascitic fluids from patients with ovarian carcinoma.

BACKGROUND: The serum markers CA125, tissue polypeptide specific antigen (TPS), and soluble interleukin-2 receptor alpha (sIL-2Ralpha) concentrations were determined in sera, cyst, and ascitic fluids from patients with malignant and benign ovarian neoplasms. METHODS: CA125, TPS, and sIL-2Ralpha concentrations were measured in sera, cyst, and ascitic fluids by immunoassays in 67 patients with carcinoma and in 32 patients with benign ovarian neoplasms. RESULTS: CA125, TPS, and sIL-2Ralpha levels were elevated significantly in sera from patients who had ovarian carcinoma compared with patients who had benign neoplasms (P < 0.001). Patients who had International Federation of Gynecology and Obstetrics (FIGO) Stage III-IV disease had significantly higher serum levels for the markers studied compared with patients who had FIGO Stage I-II disease (P < 0.001 for CA125; P = 0.02 for TPS and sIL-2Ralpha). Concurrent measurement of CA125 and sIL-2Ralpha in sera identified 100% of ovarian carcinomas in FIGO Stage I-II. All patients with carcinoma demonstrated markedly higher levels of CA125 and TPS for both cyst and ascites compared with corresponding sera (P < 0.001). The level of sIL-2Ralpha was higher statistically in ascitic fluid compared with the level in serum (P < 0.001); however, its values in sera and cyst fluids were comparable. In ascitic fluid, the CA125 level was significantly higher in patients who had FIGO Stage III-IV disease compared with patients who had FIGO Stage I-II disease (P = 0.002), whereas such correlations were not found for TPS or sIL-2Ralpha. In cyst fluids, the levels of all studied markers were independent of the FIGO stage. In cyst fluids from patients with benign ovarian neoplasms, TPS and sIL-2Ralpha levels were significantly lower compared with the levels in patients with ovarian carcinoma (P < 0.001), whereas the values of CA125 were overlapping. CA125 and TPS concentrations were higher in cyst fluids compared with corresponding sera, whereas sIL-2Ralpha levels were comparable and low in cyst fluids and in the circulation of patients with benign neoplasms. CONCLUSIONS: In patients with ovarian carcinoma, TPS and CA125 concentrations were significantly higher in the place of their generation compared with the concentrations in blood circulation. sIL-2Ralpha values were higher in ascites compared with the values in corresponding sera, and its concentrations in sera and cyst fluids were comparable. The assessment of serum sIL-2Ralpha levels showed potential complementary value to CA125 for the detection of ovarian carcinoma in early FIGO stages; however, a 9% false positive rate limited the significance of cumulative value for a combination of these circulating markers.

Ascitic Fluid↗

PubMedDate not supplied

Tumor markers in breast cancer- European Group on Tumor Markers recommendations.

Recommendations are presented for the routine clinical use of serum and tissue-based markers in the diagnosis and management of patients with breast cancer. Their low sensitivity and specificity preclude the use of serum markers such as the MUC-1 mucin glycoproteins (CA 15.3, BR 27.29) and carcinoembryonic antigen in the diagnosis of early breast cancer. However, serial measurement of these markers can result in the early detection of recurrent disease as well as indicate the efficacy of therapy. Of the tissue-based markers, measurement of estrogen and progesterone receptors is mandatory in the selection of patients for treatment with hormone therapy, while HER-2 is essential in selecting patients with advanced breast cancer for treatment with Herceptin (trastuzumab). Urokinase plasminogen activator and plasminogen activator inhibitor 1 are recently validated prognostic markers for lymph node-negative breast cancer patients and thus may be of value in selecting node-negative patients that do not require adjuvant chemotherapy.

Biomarkers, Tumor↗

PubMedDate not supplied

Serum thymidine kinase activity in dogs with malignant lymphoma: a potent marker for prognosis and monitoring the disease.

Serum thymidine kinase (sTK) activity was evaluated as a tumor marker for canine malignant lymphoma (ML). The objective was to investigate if sTK, as in humans, could be used as a prognostic marker for survival time in dogs with ML and if sTK could identify early signs of progression of disease in treated dogs. Serum samples from 52 dogs with ML were tested for initial TK activity. Samples from 21 normal dogs and 25 dogs with nonhematologic neoplasms were used for comparison. Forty-four dogs with ML were treated. Serum TK activity was measured in treated dogs before each treatment and every 4 weeks thereafter until relapse. Dogs with ML had 2-180 times higher TK activity (TK 5-900 U/L) than normal dogs (TK <7 U/L) based on the mean + 2 standard deviations. In the group of other neoplasms, only 2 dogs had a moderate increase (6.4 and 7.5 U/L) compared with the controls. Mean sTK activities in the dogs with ML that had gone into complete remission (CR) were not significantly different from activities in healthy controls (P = .68). Mean sTK at least 3 weeks before and at the time of relapse was significantly higher than activity measured at CR (P < .0001). Dogs with ML that initially had sTK >30 U/L had significantly shorter survival times (P < .0001). Furthermore, sTK activity reflected the clinical staging of ML. Measuring sTK can be used as a powerful objective tumor marker for prognosis and for predicting relapse before recurrence of clinically detectable disease in dogs with ML undergoing chemotherapy.

Animals↗