Circulating Cell-Free DNA Extraction from Liquid Biopsy for Cancer Research.

As the number of cancer patients globally increases, a need for reliable biomarkers including circulating tumour DNA from liquid biopsy for diagnosis, prognosis and monitoring of the disease is rising. Currently, mainly tissue samples from biopsy are used, but there are certain limitations: firstly, it is an invasive technique, and secondly, in some cases it is almost impossible to obtain an acceptable tissue sample. This could be changed by using circulating cell-free DNA from liquid biopsy, which also gives the possibility of repeated examination. Here, we focus on the options of isolating circulating cell-free DNA from plasma samples using two isolation techniques: precision manual QIAamp Circulating Nucleic Acid Kit and automatic MagNA Pure Compact (MPC) using Nucleic Acid Isolation Kit I. Manual extraction gave significantly better yields of circulating tumour DNA (P < 0.05). This DNA also had less contaminants (organic compounds or proteins). DNA obtained by both tested methods of isolation is suitable for subsequent molecular genetic methods.

Time and Temperature Stability of TGF-ß1, EGF and IGF-1 in 20% and 100% Human Serum.

Autologous serum eye drops (ASEDs) are used as a treatment for severe dry eye disease. The concentration and stability of various growth factors in ASEDs is determinative for their efficiency. We therefore assessed the concentrations of transforming growth factor beta 1 (TGF-ß1), epidermal growth factor (EGF) and insulin-like growth factor 1 (IGF-1) in ASEDs following storage at 4-8, -20, -80 and -156 °C. Twenty % and 100% sera from eight healthy volunteers were analysed by the sandwich enzyme immunoassay at different time intervals up to seven months. The mean levels of TGF-ß1 and EGF in undiluted and 20% serum did not differ significantly from the baseline levels in fresh serum for any storage conditions after 7 days at 4-8 °C, as well as after 4- and 7-month preservation at sub-zero temperatures. In 20% serum, no IGF-1 concentration decrease was found following 7 days of preservation at 4-8 °C. However, a decrease to 78 % and 81 % (P < 0.01) of baseline values was found in 20% serum after 4-month storage at -20 °C and 7-month storage at -156 °C, respectively. A more pronounced decrease in IGF-1 was observed in undiluted serum. All assessed growth factors present in 20% frozen serum remained stable for up to 7 months. The highest stability was achieved at -80 °C. At -20 and -156 °C, some decrease in IGF-1 occurred. Our results indicate that 20% ASEDs can be stored frozen up to 7 months under proper conditions.

Prognostic factors of renal cell carcinoma.

Renal cell carcinoma represents 23% of all adult malignancies and its incidence in the Czech Republic is one of the highest worldwide. Until late stages this disease often remains asymptomatic, which makes its diagnosis difficult. Despite an increasing proportion of small, incidentally detected tumours on imaging, approximately one third of patients are still diagnosed with advanced disease. Moreover, a relapse occurs in up to 40% of patients after surgery for localized tumour. Increased availability of imaging investigations allowing an early detection of kidney carcinoma and advances in systemic treatment have favourably affected the outcome of patients with this type of tumour. Nevertheless, mortality of renal cell carcinoma remains the highest among urological malignancies. The individual course of the disease and its response to systemic treatment are difficult to predict. A number of prognostic factors of renal cell carcinoma have been identified, of which TNM classification and tumour grade remain the most important. Recently, several multivariate prognostic models have become available, allowing a more accurate prediction of the disease course. In localized disease, they are useful in identifying patients at higher risk of recurrence and allow optimization of follow-up after surgery. In metastatic disease, they are routinely used to stratify patients into risk groups for targeted treatment. There has been a long-term effort to identify a suitable biomarker useful for an early detection and assessment of the prognosis of renal cell carcinoma. At the same time, such a biomarker could improve the accuracy of established prognostic systems. This text presents an overview of prognostic factors of renal cell carcinoma, including a summary of potential biomarkers.

The Effects of Different Storage Conditions and Repeated Freeze/Thaw Cycles on the Concentration, Purity and Integrity of Genomic DNA.

The crucial requirement of molecular genetic methods is high-quality input material. The key question is "how to preserve DNA during long-term storage." Biobanks are recommended to aliquot isolated DNA into provided volumes. The aim of this study was to analyse the effect of repeated freezing and thawing on the genomic DNA integrity, quality and concentration. The aliquoted DNA isolated from blood cells using the automatic MagNA system and manual salting out method underwent freeze/thaw cycles at different storage conditions (-20 °C, -80 °C and liquid nitrogen). The average initial concentrations were 270.6 ng/µl (salting out method) and 125.0 ng/µl (MagNA). All concentration deviations relative to the concentration after the first freeze/ thaw cycle were less than 5 % for -20 °C and -80 °C cycling with both isolation methods. The average percentage differences of liquid nitrogen samples were higher, and the MagNA isolation method showed significant differences. There were no significant changes in the DNA purity or quality. The repeating freeze/ thaw up to 100 cycles (through -20 °C and -80 °C, respectively) did not significantly influence the integrity, concentration, or purity of genomic DNA, suggesting that storage of samples in high-volume pools without multiple aliquoting is possible. Storage in a freezer seems to be the most suitable way of long-term DNA preservation, because liquid nitrogen storage leads to formation of DNA clumps.

Plasma osteopontin levels, but not its myocardial expression, reflect heart failure severity in recently diagnosed dilated cardiomyopathy.

BACKGROUND: Elevated levels of the extracellular matrix glycoprotein osteopontin (OPN) may be detected in both myocardium and plasma under various pathological conditions affecting the heart. Several studies demonstrated increased plasma OPN levels in patients with heart failure due to dilated cardiomyopathy (DCM), while other studies showed high OPN expression levels in the myocardium of such patients. However, very little is known about OPN levels in both plasma and myocardium of the same individual with DCM. Therefore, we aimed to compare plasma OPN levels and levels of myocardial OPN expression in patients with recent-onset DCM (Ro-DCM). METHODS: We examined plasma OPN as well as creatinine, C­reactive protein (CRP), brain natriuretic peptide (BNP), and troponin I levels in 25 patients with Ro-DCM. Furthermore, all subjects underwent transthoracic echocardiography, selective coronary angiography, and endomyocardial biopsy (EMB) for the assessment of myocardial OPN expression. RESULTS: No significant correlation between myocardial OPN expression and clinical, biochemical, or echocardiographic parameters was found. In log transformation analysis, plasma OPN levels correlated significantly with BNP levels (r = 0.46, p = 0.031), with CRP levels (r = 0.52, p = 0.015), and with early diastolic mitral annular velocity (r = -0.57, p = 0.009). There was a borderline association between the plasma OPN log value and New York Heart Association class (p = 0.053). CONCLUSION: Plasma OPN levels reflect heart failure severity in patients with Ro-DCM. Myocardial OPN expression is not associated with either plasma OPN levels or markers of heart failure in these individuals.

The significance of calprotectin, CD147, APOA4 and DJ-1 in non-invasive detection of urinary bladder carcinoma.

Aim of the study is to define the diagnostic accuracy of selected urinary protein biomarkers in the non-invasive detection of primary and recurrent urothelial carcinoma of the urinary bladder. The urinary levels of calprotectin, CD147, APOA4 and protein deglycase DJ-1 were examined in 255 individuals, including 60 controls with non-malignant urological disease, 61 patients with a history of urinary bladder cancer with negative cytology and negative cystoscopy and 134 patients with urinary bladder cancer. Urinary concentrations of biomarkers were determined by Enzyme-Linked Immunosorbent Assay (ELISA). During the follow-up of patients with non-muscle invasive bladder cancer (NMIBC), a group of 44 patients with cancer recurrence was compared to the group of 61 patients with a history of NMIBC but with no evidence of disease. Urinary concentrations of the evaluated markers did not reveal any significant difference between these groups. During the primary diagnosis, a group of 90 patients with primary bladder cancer and 60 subjects with benign disease were compared. Urinary levels of CD147 were not significantly higher in patients with tumors. The greatest diagnostic accuracy was observed in APOA4 (sensitivity 55.6, specificity 83.3, AUC 0.75), and lesser in calprotectin (sensitivity 39.4, specificity 87.7, AUC 0.66) and in DJ-1 (sensitivity 61.1, specificity 66.7, AUC 0.64), respectively. Apolipoprotein A4 may be used potentially as a supplemental urinary marker in the diagnosis of primary bladder cancer.

Plasma osteopontin levels in patients with dilated and hypertrophic cardiomyopathy.

BACKGROUND: Osteopontin (OPN) is an extracellular matrix glycoprotein that plays a role in a variety of cellular activities associated with inflammatory and fibrotic responses. Increased OPN levels in myocardium and plasma have been demonstrated in patients with dilated cardiomyopathy (DCM). However, nothing is known about OPN levels in patients with hypertrophic cardiomyopathy (HCM). Therefore, the aim of our study was to compare plasma OPN levels in patients with these two most common cardiomyopathies. PATIENTS AND METHODS: We examined plasma OPN as well as creatinine, C­reactive protein (CRP), brain-type natriuretic peptide (BNP), and troponin I levels in 64 patients with DCM, 43 patients with HCM, and 75 control subjects. Transthoracic echocardiography was also performed on all cardiomyopathy patients. RESULTS: Plasma OPN levels were significantly elevated in patients with DCM compared with HCM patients (95 ± 43 vs. 57 ± 21 ng/ml; p < 0.001) and control subjects (54 ± 19 ng/ml; p < 0.001); however, there was no difference between HCM patients and control subjects. New York Heart Association (NYHA) class III or IV disease was more frequently present in DCM patients than in HCM subjects (44 % vs. 2 %, p < 0.0001). In multivariate analysis, BNP and CRP levels together with NYHA class were found to be significant predictors of plasma OPN levels in DCM patients (p = 0.002, p = 0.029, and p < 0.001 for BNP, CRP, and NYHA, respectively). CONCLUSION: Plasma OPN levels were associated with overall heart failure severity rather than with specific cardiomyopathy subtype in patients suffering from DCM or HCM, respectively.

Matrix Metalloproteinases and Their Tissue Inhibitors: an Evaluation of Novel Biomarkers in ANCA-Associated Vasculitis.

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) may play an important role in both inflammation with subsequent fibrosis and in repair and healing in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We evaluated the circulating levels of MMPs, including pregnancy-associated plasma protein A (PAPP-A), and TIMPs in patients with AAV. PAPP-A, MMP-2, MMP-3, MMP-7, MMP-9, TIMP-1, TIMP-2 and selected parameters were measured in 100 AAV patients (36 patients with active disease and 64 patients in remission) and 34 healthy subjects. The levels of MMP-2, MMP-3, MMP-7, MMP-9, TIMP-1, TIMP-2, and PAPP-A in AAV were all found to be different to those of the controls. The MMP-7 and PAPP-A concentrations were increased in active disease in comparison to the controls (MMP-7: 13 ±.7 vs. 2 ± 0.6 ng/ml, PAPP-A: 14 ± 18 vs. 6.8 ± 2.6 ng/ml, both P < 0.005). The MMP-2 and TIMP-2 levels were increased in remission when compared to the controls (MMP-2: 242 ± 50 ng/ml vs. 212 ± 26 ng /ml, TIMP-2: 82 ± 14 ng/ml vs. 68 ± 93 ng/ml) and to the active AAV (MMP-2: 242 ± 50 vs. 219 ± 54 ng/ml, TIMP-2: 82 ± 14 ng/ml vs. 73 ± 15 ng/ml, all P < 0.005). MMP-3, MMP-7, TIMP-1, and PAPP-A correlated with serum creatinine. The serum levels of MMPs, TIMPs and PAPP-A are all altered in AAV. MMP-2, MMP-7 and TIMP-2 appear to be promising markers in distinguishing active AAV from remission. MMP-3, MMP-7, TIMP-1, and PAPP-A are associated with kidney function in AAV. Further studies are needed to delineate the exact roles of circulating MMPs, TIMPs and PAPP-A in patients with AAV.

The importance of serum osteopontin and stanniocalcin-1 in renal cell carcinoma.

A total of 56 RCC patients with staging ≥ pT1b were enrolled in a prospective study to assess the prognostic importance of serum levels of osteopontin (OP), stanniocalcin-1 (SC), FGF-23, alpha Klotho and 25-OH-D at the time of diagnosis in renal cell carcinoma (RCC) patients. The relationship between the serum level of the analyzed parameters and recurrence-free survival (RFS), overall survival (OS) and cancer-specific survival (CSS) was examined, and our control group consisted of 20 patients without cancer. The levels of osteopontin, stanniocalcin-1, FGF-23 and alpha Klotho were determined by Enzyme-Linked Immunosorbent Assay (ELISA) and 25-OH-D by chemiluminiscence immunoanalysis (CLIA). The follow-up period median was 46 months. Renal cell carcinoma recurred in 9 patients and 20 patients died during follow-up; 12 of them from RCC. The level of osteopontin and stanniocalcin-1 varied between the control group and RCC patients (at p=0.02 and p=0.0003). Higher levels of stanniocalcin-1 were detected in the metastatic RCC group than in the localized RCC group (p=0.003). Only the stanniocalcin-1 level at the time of surgery was associated with RFS (p=0.0004). Both OS and CCS were associated with the osteopontin, stanniocalcin-1 and FGF preoperative level. Patients with stanniocalcin-1 level over 1,277 pg/ml and osteopontin level over 100 ng/ml had 17.8 times higher and 7.9 times higher risk of dying from RCC progression, respectively (p<0.001 and p=0.002). High levels of osteopontin, stanniocalcin-1 and FGF 23 at the time of surgery are important prognostic factors related to CSS and OS. Patients with high stanniocalcin-1 level were at risk of tumor recurrence.

RAGE and its ligands in cancer - culprits, biomarkers, or therapeutic targets?

Receptor for advanced glycation end products (RAGE) plays a central role in the regulation of tissue homeostasis, regeneration and resolution of inflammation, but under pathological conditions RAGE-mediated pathways may induce diminished apoptosis, but enhanced autophagy and cell necrosis. These mechanisms may contribute to malignant transformation, cancer progression and metastases. Soluble RAGE may bind natural RAGE ligands and counteract some of the RAGE-mediated effects. Activation of RAGE was demonstrated in different types of cancer (including colon, pancreatic and breast cancer). Expression of RAGE and serum levels of soluble RAGE may serve as cancer biomarkers and strategies aimed at interfering with RAGE signaling might be promising anticancer drugs.

Trefoil factor family (TFF) proteins as potential serum biomarkers in patients with metastatic colorectal cancer.

Trefoil factor family (TFF) is composed of three secretory proteins (TFF1, TFF2 and TFF3) that play an important role in mucosal protection of gastrointestinal tract. Their overexpression in colorectal tumors seems to be associated with more aggressive disease. We collected serum samples from 79 healthy controls and 97 patients with metastatic colorectal cancer at the time of diagnosis or at progression. Serum levels of TTF1-3, CEA and CA19-9 were measured by ELISA. Serum TFF1 and TFF3 levels were significantly higher in patients with colorectal cancer compared to healthy controls (p < 0.0001). Moreover, serum levels of TFF3 correlated with extent of liver involvement in patient without pulmonary metastases and patients with higher TFF3 levels had significantly worse outcome (p < 0.0001). Compared to CEA and CA19-9, TFF3 had higher sensitivity and the same specificity. Our results indicate that TFF3 is an effective biomarker in patients with metastatic colorectal cancer with higher sensitivity than CEA a CA19-9. TFF3 levels strongly correlate with extension of liver disease and seem to have prognostic value.

Tumor markers in colorectal cancer, gastric cancer and gastrointestinal stromal cancers: European group on tumor markers 2014 guidelines update.

Biomarkers currently play an important role in the detection and management of patients with several different types of gastrointestinal cancer, especially colorectal, gastric, gastro-oesophageal junction (GOJ) adenocarcinomas and gastrointestinal stromal tumors (GISTs). The aim of this article is to provide updated and evidence-based guidelines for the use of biomarkers in the different gastrointestinal malignancies. Recommended biomarkers for colorectal cancer include an immunochemical-based fecal occult blood test in screening asymptomatic subjects ≥50 years of age for neoplasia, serial CEA levels in postoperative surveillance of stage II and III patients who may be candidates for surgical resection or systemic therapy in the event of distant metastasis occurring, K-RAS mutation status for identifying patients with advanced disease likely to benefit from anti-EGFR therapeutic antibodies and microsatellite instability testing as a first-line screen for subjects with Lynch syndrome. In advanced gastric or GOJ cancers, measurement of HER2 is recommended in selecting patients for treatment with trastuzumab. For patients with suspected GIST, determination of KIT protein should be used as a diagnostic aid, while KIT mutational analysis may be used for treatment planning in patients with diagnosed GISTs.

Endotelial activation and flow-mediated vasodilation in young patients with breast cancer.

Endothelial activation and dysfunction may play a significant role in the progression of breast cancer. In our study we examined markers of endothelial activation (soluble ICAM-1, P-selectin, E-selectin) in 98 young patients with breast cancer (< 40 years). In 50 of them (and 20 age-matched controls) we also measured flow mediated vasodilation. Patients with breast cancer had significantly higher serum levels of soluble E-selectin, P-selectin and ICAM-1, P-selectin was higher in patients with larger tumors, node involvement and seemed to be apredictor of poor outcome. We were unable to find significant difference in the parameters of flow mediated vasodilation between patients with breast cancer and healthy subjects, although both peak blood flow (PBF) and flow mediated vasodilation (FMD) seemed to be skewed compared to healthy subjects toward mean and lower levels. Cluster analysis enabled us to distinguish several larger groups of patients with different degree of endothelial activation and function and different outcome. Group of patients with high E-selectin, high ICAM-1 (higher endothelial activation) and low VEGF (putative endothelial damage) had more frequently negative estrogen receptors and had worse outcome compared to the group of patients with lower E-selectin, lower ICAM-1 and mostly positive estrogen receptors. Further studies of larger groups of patients should help to identify the panel of endothelial markers which could help in predicting the outcome of young patients with breast cancer.

Pregnancy-associated plasma protein A polymorphisms in patients with risk pregnancies.

Pregnant women are often threatened by hypertension, symptoms of preterm labour, hepatopathy, and other. These complications might be the consequence of genetic factors together with involvement of environmental factors. We were searching for three polymorphisms Arg654Lys, Ala678Pro and Thr686Ala in exon 5, and two polymorphisms Phe802Leu, Ser827Ser/Leu in exon 7, and for the new mutations in exons 5 and 7 of the pregnancy-associated plasma protein A gene in the studied group consisting of 203 women - 79 pregnant women in time of preterm labour, 24 pregnant women suffering from preeclampsia, and 100 healthy pregnant and non-pregnant women serving as controls. We did not find any divergence from wild-type form of these polymorphisms in any of the studied groups, which led us to the hypothesis that these polymorphisms are not associated with our studied group of Caucasian origin. However, further studies with a larger group of subjects are needed to confirm our results.

Pancreatic stellate cells - rising stars in pancreatic pathologies.

Pluripotent pancreatic stellate cells (PSCs) receive growing interest in past decades. Two types of PSCs are recognized -vitamin A accumulating quiescent PSCs and activated PSCs- the main producents of extracellular matrix in pancreatic tissue. PSCs plays important role in pathogenesis of pancreatic fibrosis in pancreatic cancer and chronic pancreatitis. PSCs are intensively studied as potential therapeutical target because of their important role in developing desmoplastic stroma in pancreatic cancer. There also exists evidence that PSC are involved in other pathologies like type-2 diabetes mellitus. This article brings brief characteristics of PSCs and recent advances in research of these cells.

The effect of surgery on the levels of matrix metalloproteinases in patients with inguinal hernia.

Matrix metalloproteinases (MMPs) are associated with the alteration of extracellular matrix. The purpose of this study was to investigate how the levels of matrix metalloproteinases and their inhibitors - TIMPs are influenced by the presence of inguinal hernia as well as by its surgical treatment. The studied group consisted of 25 patients with inguinal hernia and 21 healthy controls for comparison. Two blood samples - before and after the treatment were collected from patients. Serum concentrations of MMPs and TIMPs were analysed by multiplex immunoassays. There was a difference in circulating levels of MMPs in patients before the surgery compared to healthy controls - the concentrations of MMP-2 and MMP-9 were significantly lower (p=0.026, p=0.018, respectively). After the surgery, the levels of MMPs, especially MMP-2 (p<0.0001), were significantly decreased in patients compared to the preoperative values, apart from MMP-9. On the contrary, MMP-9 showed significant increase after the surgery (p<0.0001). Circulation levels of TIMP-2 in patients were significantly decreased in comparison with controls (p=0.004), whereas levels of TIMP-1 were similar to controls. Both tested metalloproteinase inhibitors showed a significant decrease in detected levels (TIMP-1 p=0.0004; TIMP-2 p<0.0001) after the procedure compared to the preoperative values. The levels of MMPs, especially MMP-2 and MMP-9, and their inhibitors TIMP-1 and TIMP-2 are involved by the presence of inguinal hernia as well as are influenced by the surgery.

Levels of circulating biomarkers at rest and after exercise in coronary artery disease patients.

As traditional risk factors are unable to fully explain the pathogenesis of coronary artery disease (CAD), novel mechanisms became a target of many investigations. Our aim was to study the response of selected markers to physical exercise. High-sensitive C-reactive protein (hs-CRP), matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), advanced oxidation protein products (AOPP), soluble receptor for advanced glycation end-products (sRAGE), pregnancy-associated plasma protein A (PAPP-A), E-selectin, vascular endothelial growth factor (VEGF) and B-type natriuretic peptide (BNP) levels were measured in serum of 21 CAD patients and in 22 healthy controls at rest and after exercise bicycle stress test performed up to the maximal tolerated effort. At rest, hs-CRP, AOPP, MMP-9 and BNP were significantly elevated in the CAD patients as compared with controls. In contrast, P-selectin was significantly lower in CAD patients and a tendency to lower levels of sRAGE was noted. After exercise MMP-9 and BNP, increased significantly in both groups. In conclusions, CAD patients have elevated hs-CRP, AOPP, MMP-9 and BNP--novel markers related to cardiovascular risk or left ventricular overload. MMP-9 and BNP increase significantly with exercise in both healthy individuals and CAD patients.

Is maternal progesterone actually independent of the fetal steroids?

Progesterone and estradiol are the foremost steroid hormones in human pregnancy. However, the origin of maternal progesterone has still not been satisfactorily explained, despite the generally accepted opinion that maternal LDL-cholesterol is a single substrate for placental synthesis of maternal progesterone. The question remains why the levels of progesterone are substantially higher in fetal as opposed to maternal blood. Hence, the role of the fetal zone of fetal adrenal (FZFA) in the synthesis of progesterone precursors was addressed. The FZFA may be directly regulated by placental CRH inducing an excessive production of sulfated 3beta-hydroxy-5-ene steroids such as sulfates of dehydroepiandrosterone (DHEAS) and pregnenolone (PregS). Due to their excellent solubility in plasma these conjugates are easily transported in excessive amounts to the placenta for further conversion to the sex hormones. While the significance of C19 3beta-hydroxy-5-ene steroid sulfates originating in FZFA for placental estrogen formation is mostly recognized, the question "Which maternal and/or fetal functions may be served by excessive production of PregS in the FZFA?" - still remains open. Our hypothesis is that, besides the necessity to synthesize de novo all the maternal progesterone from cholesterol, it may be more convenient to utilize the fetal PregS. The activities of sulfatase and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) are substantially higher than the activity of cytochrome P450scc, which is rate-limiting for the placental progesterone synthesis from LDL-cholesterol. However, as in the case of progesterone synthesis from maternal LDL-cholesterol, the relative independence of progesterone levels on FZFA activity may be a consequence of substrate saturation of enzymes converting PregS to progesterone. Some of the literature along with our current data (showing no correlation between fetal and maternal progesterone but significant partial correlations between fetal and maternal 20alpha-dihydroprogesterone (Prog20alpha) and between Prog20alpha and progesterone within the maternal blood) indicate that the localization of individual types of 17beta-hydroxysteroid dehydrogenase is responsible for a higher proportion of estrone and progesterone in the fetus, but also a higher proportion of estradiol and Prog20alpha in maternal blood. Type 2 17beta-hydroxysteroid dehydrogenase (17HSD2), which oxidizes estradiol to estrone and Prog20alpha to progesterone, is highly expressed in placental endothelial cells lining the fetal compartment. Alternatively, syncytium, which is directly in contact with maternal blood, produces high amounts of estradiol and Prog20alpha due to the effects of type 1, 5 and 7 17?-hydroxysteroid dehydrogenases (17HSD1, 17HSD5, and 17HSD7, respectively). The proposed mechanisms may serve the following functions: 1) providing substances which may influence the placental production of progesterone and synthesis of neuroprotective steroids in the fetus; and 2) creating hormonal milieu enabling control of the onset of labor.

[Progesterone neuroactive metabolites in human pregnancy]. / Progesteron a jeho neuroaktivní metabolity v mechanismu porodu.

OBJECTIVE: Review of the physiological role of neuroactive and neuroprotective steroids in human pregnancy. DESIGN: A review article. SETTING: Gynecological-Obstetrical Clinic, 1st Medical Faculty, Charles University and General Hospital, Prague. CONCLUSION: Human parturition is a multi-factorial process. Various mechanisms related to the onset of labor were suggested. Estrogens show accelerating increase in late pregnancy, which probably reflect the increasing activity of fetal zone of the fetal adrenal. This zone is stimulated by progressive increase of placental CRH resulting in excessive production of conjugated 3beta-hydroxy-5-en-steroids, which are transported by circulation to placenta and further metabolized to active hormones. Some progesterone metabolites probably participate in pregnancy sustaining via modulation of ligand-gated ion channels in the CNS and periphery. In this review, the question was addressed whether the catabolism of pregnancy sustaining progesterone metabolites accelerate like the estrogen formation.

Comparison of three methods for determination of glucose.

Study refers comparison of three methods for glucose determination - precision (repeatability, reproducibility), traceability to SRM 965a NIST, comparability in blood-pools and in patients' samples: Electrochemical determination on Super GL (DiaSys, Germany) in hemolyzate - GL method, spectrophotometric determination using hexokinase (Glucose System Reagent 800, Olympus) - HKL method - and using glucose dehydrogenase (Glucose Gluc-DH, EcolineS+, DiaSys, Germany) - GDL method - in hemolyzate. For showing differences between the concentration of glucose in hemolyzed blood and corresponding plasma, spectrophotometric determination using hexokinase in plasma was used (Glucose System Reagent 800, Olympus) - HKP method. Coefficients of variation characterizing precision under repeatability and reproducibility conditions are not higher than 3.0% for the GL method, 6.3% for the GDL method and 15.8% for the HKL method with low sensitivity. For glucose concentration less than 8 mmol/l, HKL tends to give lower results than GDL, and GL tends to give higher results than GDL. For glucose concentration about 2 mmol/l, the results of glucose in plasma - HKP method - tend to be significantly lower (by more than ten percent) than in corresponding total (hemolyzed) blood. HKL method can be reasonably used in a high number of parallel determinations. For glucose 8 mmol/l and lower, comparability of results given by HKL, GDL and GL methods gradually worsens, while for glucose between 8 and 34 mmol/l results of the three mentioned methods are well comparable.