Role of biomarkers in adult sepsis and their application for a good laboratory practice: a pilot study.

This study measured Procalcitonin (PCT), Presepsin (PRE-S) and pro-Adrenomedullin (pro-ADM) in intensive care unit (ICU) patient’s blood to assess their contribution to accurate diagnosis of sepsis and potential predictive impact on prognosis. The final aim was to improve the use of infection biomarkers for optimizing the impact of laboratory medicine on clinical outcomes, focusing on the good management of resources designed to produce maximum effectiveness and efficiency. Sixty-four adult patients were studied during their hospitalization in ICU; blood samples were collected and categorized according to their clinical diagnosis and illness severity, and sepsis marker levels were measured on automated immunoassay platforms. PCT, PRE-S and pro-ADM infection markers were significantly lower in controls than in sepsis or septic shock groups. The area under the curve, by ROC curve analysis, was 0.945 for PCT, 0.756 for PRE-S and 0.741 for pro-ADM. Sepsis diagnostic accuracy was not improved by combining PCT, PRE-S and pro-ADM measures. Preliminary data demonstrated that, despite PRE-S and pro-ADM being able to differentiate between septic and non-septic patients with accuracy, PCT remains the most reliable marker available. The results obtained still do not allow us to consider a combination of markers, because it would merely increase laboratory costs without improving diagnostic performance. Furthermore, the results confirm a possible prognostic role of pro-ADM in septic states, but no correlation between biomarker levels and survival at 48 h was detected. Hence PCT, PRE-S, nor pro-ADM can be used to predict short-term prognosis.

Preliminary evaluation of the new TACR flex method versus MEIA method in the therapeutic monitoring of tacrolimus in organ transplantation.

Tacrolimus (FK506) is an effective macrolide immunosuppressant widely used to prevent organ rejection following transplantation. Monitoring blood levels of tacrolimus is essential to assess organ rejection versus toxicity, because of the narrow therapeutic range and pharmacokinetic variability. The increased request for therapeutic drug monitoring is an interesting challenge for clinical laboratories. The automated immunoassay methods provide correct results and a turnaround time considerably reduced compared to HPLC and HPLC-MS which remain the gold standard for accuracy and economical advantages. A new immunoassay method, TACR Flex Dimension, is a commercially available, automated pretreatment test. The purpose of this study was to compare two analytical methods: the MEIA II tacrolimus immunoassay using the IMx analyzer and the new TACR Flex tacrolimus immunoassay on the Dimension system. Tacrolimus results obtained using the two methods were compared using European control and 93 whole blood samples from kidney and liver transplant patients. The tacrolimus concentrations measured by Flex Dimension for all samples were higher (0.7 to 16.1 ng/mL) than results obtained with MEIA (0.2 to 13.4 ng/mL), a mean difference expressed in percentage of 31.7%, and a correlation coefficient of 0.85. The data obtained by both methods using three European controls showed similar concentrations. The TACR Flex Dimension method provided a higher automation level and therefore a lower incidence of preanalytical errors and a lower turnaround time.

Reactive oxygen intermediates mediate angiotensin II-induced c-Jun.c-Fos heterodimer DNA binding activity and proliferative hypertrophic responses in myogenic cells.

Angiotensin II (Ang-II) receptor engagement activates many immediate early response genes in both vascular smooth muscle cells and cardiomyocytes whether a hyperplastic or hypertrophic response is taking place. Although the signaling pathways stimulated by Ang-II in different cell lines have been widely characterized, the correlation between the generation of different second messengers and specific physiological responses remains relatively unexplored. In this study, we report how in both C2C12 quiescent myoblasts and differentiated myotubes Ang-II significantly stimulates AP1-driven transcription and c-Jun.c-Fos heterodimer DNA binding activity. Using a set of different protein kinase inhibitors, we could demonstrate that Ang-II-induced increase in AP1 binding is not mediated by the cAMP-dependent pathway and that both protein kinase C and tyrosine kinases are involved. The observation that in quiescent myoblasts Ang-II increase of AP1 binding and induction of DNA synthesis and, in differentiated myotubes, Ang-II stimulation of protein synthesis are abolished by the cysteine-derivative and glutathione precursor N-acetyl-L-cysteine strongly suggests a role for reactive oxygen intermediates in the intracellular transduction of Ang-II signals for immediate early gene induction, cell proliferation, and hypertrophic responses.

Reactive oxygen intermediates (ROIs) are involved in the intracellular transduction of angiotensin II signal in C2C12 cells.

Increasing evidence suggests that angiotensin II may act as a growth factor for several muscle cell types. Angiotensin II stimulation activates many immediate early response genes like c-Fos, c-Jun, c-Myc and Egr-1 in both vascular smooth muscle cells and cardiomyocytes, independently of whether a hyperplastic or hypertrophic response is taking place. In this study we report that angiotensin II significantly stimulates AP1-driven transcription in mouse skeletal muscle cells C2C12 stably transfected with a TRE-tk-CAT plasmid in a dose-dependent manner (peak stimulation at 10(-5) M of angiotensin II). Moreover, angiotensin II increases the binding of the AP1 complex to its DNA target in both quiescent C2C12 myoblasts and in differentiated C2C12 myotubes. Most of the TRE-bound complexes in both unstimulated and angiotensin II-treated cells consist of c-jun/c-fos heterodimers. Using a set of different protein kinase inhibitors, including HA1004, H7, tyrphostin, genistein and staurosporine, we could demonstrate that the angiotensin II-induced AP1 binding increase is not mediated by the cAMP-dependent pathway and that protein kinase C and tyrosine kinases are involved. Treatment of C2C12 cells with H2O2 induces a dose-dependent increase in c-jun/c-fos heterodimer binding, specifically reverted by the cysteine derivative and glutathione precursor N-acetyl-L-cysteine (NAC). The observation that the induction by angiotensin II of both the AP1 DNA binding activity and DNA synthesis in quiescent C2C12 myoblasts is abolished by NAC strongly suggests a role for reactive oxygen intermediates (ROIs) in the intracellular transduction of angiotensin II signals for immediate early gene induction and for cell proliferation.

Modulation of intracellular signal transduction pathways by the hepatitis B virus transactivator pX.

The mechanisms by which pX, the transactivator of the hepatitis B virus (HBV), exerts its effects on transcription of viral and cellular genes and affects cell-growth regulation have not yet been fully defined. Previous reports suggested the possibility of a direct interaction of pX, which lacks intrinsic DNA-binding activity, with components of the cellular transcription machinery. More recent investigations support the hypothesis that pX might activate cellular kinases involved in transcriptional regulation and growth control. We characterized the mechanisms of AP-1 transcription factor activation by pX and, in particular, the role of cellular proteins involved in the intracellular signal transduction of growth-factor receptors. The observation that the overexpression of c-fos and c-jun in the cells results in a clear augmentation of the effects of pX on TRE-directed transcription and the induction of the DNA-binding activity of c-jun/c-fos heterodimers by AP1-depleted nuclear extracts from pX-expressing cells strongly supports the involvement of post-translational modifications. In both HeLa and undifferentiated F9 cells, pX was able to increase the activity of exogenous transfected c-jun but not of c-jun mutants bearing mutations in the serine residues located in the amino-terminal transcriptional activation domain. Moreover, by use of Ha-ras and Raf-1 dominant negative mutants, we show that both Ha-ras and Raf-1 are required for pX-induced activation of c-jun transcriptional activity.(ABSTRACT TRUNCATED AT 250 WORDS)

The hepatitis B virus (HBV) pX transactivates the c-fos promoter through multiple cis-acting elements.

The hepatitis B virus (HBV) X protein (pX) stimulates transcription regulated by cis-acting elements that control many viral and cellular genes, including the c-myc and the c-fos proto-oncogenes. Using several c-fos promoter deletion mutants, we found the serum-responsive element (SRE) located at -315, the modified TPA-responsive element located at -296 (fos-AP-1 binding site, FAP) and the region spanning from nucleotide -220 to -120, which contains an NF1-like site and several stretches of sequence homologous to the AP-2 consensus binding sites, to be responsive to pX. pX does not modify the pattern of the retarded complexes bound to the SRE/FAP region which, in our system, appears to be occupied by SRE-binding factors. The activation of the SRE does not involve complex formation between SRE-binding factors and pX, it is not associated with an increase in serum response factor binding to the SRE and it does not determine changes in SRE mobility-shift pattern.

Characterization of the hepatitis B virus preS/S region encoded transcriptional transactivator.

A transactivating function generated by carboxy-terminal truncation of the HBV envelope proteins has been recently described. To characterize the preS/S protein domains responsible for transactivation, preS1/S2/S and preS2/S 3' deletion mutants under the control of the adenoviral major late promoter were tested for their transactivating potential in cotransfection experiments using the c-myc and c-fos regulatory sequences as targets. Deletion of the carboxyterminal hydrophobic domain of the S protein and the presence of the endoplasmic reticulum insertion signal I (ER signal I) are required for the generation of the preS/S transactivating function. Multiple transcription factors binding sites (i.e., TRE, SRE, and NFkB sites) mediated the truncated preS/S-induced activation of the target regulatory sequences. The transactivation phenomenon is linked, at least in part, to the protein kinase C signaling pathway.

Truncated pre-S/S proteins transactivate multiple target sequences.

In order to investigate the transactivational function of HBV truncated preS/S proteins we have constructed two sets of plasmids and have tested their transactivational potential on the c-myc regulatory sequences and the TPA-responsive element. We found that preS/S proteins only become transactivationally active when truncated at the carboxy terminal end. Furthermore, using immunofluorescence microscopy we determined that the proteins are located exclusively in the cytoplasm, apparently ruling out DNA binding and activation of factors in the nucleus.