CXC chemokine ligand 4 (CXCL4) is predictor of tumour angiogenic activity and prognostic biomarker in non-small cell lung cancer (NSCLC) patients undergoing surgical treatment

Objective: To evaluate the association of CXC chemokine ligand 4 (CXCL4) plasma levels with tumour angiogenesis in non-small cell lung cancer (NSCLC) and to assess association of CXCL4 with clinical outcomes.

Patients and methods: Fifty patients with early stage NSCLC who underwent pulmonary resection. CXCL4 levels were analysed by ELISA. Angiogenesis was assessed by immunohistochemistry, and microvessel density (MVD) count.

Results: There was positive correlation between MVD and CXCL4 levels. Patients with higher CXCL4 levels had worse overall and disease-free survival.

Conclusions: Plasma levels of CXCL4 are associated with tumour vascularity. Increased CXCL4 levels in NSCLC patients undergoing treatment may indicate active cancer-induced angiogenesis associated with relapse and worse outcome.     

Soluble RAGE, diabetic nephropathy and genetic variability in the AGER gene

Diabetes mellitus, especially when complicated with decline of renal function due to diabetic nephropathy (DN), is associated with accumulation of advanced glycation end products (AGEs) exerting their adverse effects via receptor of AGE (RAGE). Soluble RAGE (sRAGE) is a truncated form of RAGE functioning as an inhibitor of AGE-mediated signalling. We studied relationships between sRAGE, renal function and genetic variability in the AGER gene in diabetic subjects. Study comprised a total of 265 diabetics (type 1 or 2 or LADA) with normoalbuminuria (n = 94) or DN (n = 171). sRAGE (assessed by ELISA) was significantly higher in DN than normoalbuminuria subjects (P = 0.007) and positively correlated with age, S-urea, S-creatinine and albuminuria and AGEs (determined spectrofluorimetrically), negatively with GFR (all P < 0.05); however, multivariate regression revealed that GFR was the only independent variable associated with sRAGE (P = 0.047). sRAGE did not correspond with carrier state of risk-haplotype copies (RAGE2) (P > 0.05). In conclusion, GFR is a principal determinant of sRAGE concentration and gradual sRAGE increase in subjects with advancing impairment of renal function is paralleled by AGEs.     

The oligodeoxynucleotide sequences corresponding to never-expressed peptide motifs are mainly located in the non-coding strand

Background  

We study the usage of specific peptide platforms in protein composition. Using the pentapeptide as a unit of length, we find that in the universal proteome many pentapeptides are heavily repeated (even thousands of times), whereas some are quite rare, and a small number do not appear at all. To understand the physico-chemical-biological basis underlying peptide usage at the proteomic level, in this study we analyse the energetic costs for the synthesis of rare and never-expressed versus frequent pentapeptides. In addition, we explore residue bulkiness, hydrophobicity, and codon number as factors able to modulate specific peptide frequencies. Then, the possible influence of amino acid composition is investigated in zero- and high-frequency pentapeptide sets by analysing the frequencies of the corresponding inverse-sequence pentapeptides. As a final step, we analyse the pentadecamer oligodeoxynucleotide sequences corresponding to the never-expressed pentapeptides.     

Optimizing the medium perfusion rate in bone tissue engineering bioreactors

There is a critical need to increase the size of bone grafts that can be cultured in vitro for use in regenerative medicine. Perfusion bioreactors have been used to improve the nutrient and gas transfer capabilities and reduce the size limitations inherent to static culture, as well as to modulate cellular responses by hydrodynamic shear. Our aim was to understand the effects of medium flow velocity on cellular phenotype and the formation of bone‐like tissues in three‐dimensional engineered constructs. We utilized custom‐designed perfusion bioreactors to culture bone constructs for 5 weeks using a wide range of superficial flow velocities (80, 400, 800, 1,200, and 1,800 µm/s), corresponding to estimated initial shear stresses ranging from 0.6 to 20 mPa. Increasing the flow velocity significantly affected cell morphology, cell–cell interactions, matrix production and composition, and the expression of osteogenic genes. Within the range studied, the flow velocities ranging from 400 to 800 µm/s yielded the best overall osteogenic responses. Using mathematical models, we determined that even at the lowest flow velocity (80 µm/s) the oxygen provided was sufficient to maintain viability of the cells within the construct. Yet it was clear that this flow velocity did not adequately support the development of bone‐like tissue. The complexity of the cellular responses found at different flow velocities underscores the need to use a range of evaluation parameters to determine the quality of engineered bone. Bioeng. 2011; 108:1159–1170. © 2010 Wiley Periodicals, Inc.     

Conjugates of adenosine mimetics and arginine-rich peptides serve as inhibitors and fluorescent probes but not as long-lifetime photoluminescent probes for protein arginine methyltransferases

The conjugates of an adenosine mimetic and oligo-l -arginine or oligo-d -arginine (ARCs) were initially designed in our research group as inhibitors and photoluminescent probes targeting basophilic protein kinases. Here, we explored a panel of ARCs and their fluorescent derivatives in biochemical assays with members of the protein arginine methyltransferase (PRMT) family, focusing specifically on PRMT1. In the binding/displacement assay with detection of fluorescence anisotropy, we found that ARCs and arginine-rich peptides could serve as high-affinity ligands for PRMT1, whereas the equilibrium dissociation constant values depended dramatically on the number of arginine residues within the compounds. The fluorescently labeled probe ARC-1081 was displaced from its complex with PRMT1 by both S-adenosyl-l -methionine (SAM) and S-adenosyl-l -homocysteine (SAH), indicating binding of the adenosine mimetic of ARCs to the SAM/SAH-binding site within PRMT1. The ARCs that had previously shown microsecond-lifetime photoluminescence in complex with protein kinases did not feature such property in complex with PRMT1, demonstrating the selectivity of the time-resolved readout format. When tested against a panel of PRMT family members in single-dose inhibition experiments, a micromolar concentration of ARC-902 was required for the inhibition of PRMT1 and PRMT7. Overall, our results suggest that the compounds containing multiple arginine residues (including the well-known cell-penetrating peptides) are likely to inhibit PRMT and thus interfere with the epigenetic modification status in complex biological systems, which should be taken into consideration during interpretation of the experimental data.     

"In vivo" (35S)methionine interaction with rat liver tRNA

As part of a study to characterize the methionine role in tumorigenesis, we report that methionine sulfur interacts with rat liver tRNA "in vivo" (35S) radioactivity remained associated to the nucleic acid after a number of treatments, including tRNA deacylation. Similar data were obtained after administration of (methyl-3H) methionine, while no comparable tRNA labelling was detected when the aminoacid labelled in the aliphatic chain was given. Hplc analysis of (35S) tRNA enzymic hydrolysate showed two unidentified UV-absorbing radioactive peaks. NMR spectra of these two peaks did not reveal any thiomethyl group.     

Indirect estimation of reference intervals for thyroid parameters using advia centaur XP analyzer

BackgroundThe aim of this study was to determine the reference intervals (RIs) for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) and FT3/FT4 ratio using indirect methods.MethodsWe analyzed 1256 results TSH, FT4 and FT3 collected from a laboratory information system between 2017 and 2021. All measurements were performed on a Siemens ADVIA Centaur XP analyzer using the chemiluminescent immunoassay. We calculated the values of the 2.5th and 97.5th percentiles as recommended by the IFCC (CLSI C28-A3).ResultsThe RIs derived for TSH, FT4, FT3 and FT3/FT4 ratio were 0.34-4.10 mIU/L, 11.3-20.6 pmol/L, 3.5-6.32 pmol/L and 0.21-0.47, respectively. We found a significant difference between calculated RIs for the TSH and FT4 and those recommended by the manufacturer. Also, FT3 values were significantly higher in the group younger than 30 years relative to the fourth decade (5.26 vs. 5.02, p=0.005), the fifth decade (5.26 vs. 4.94, p=0.001), the sixth decade (5.26 vs. 4.87, p<0.001), the seventh decade (5.26 vs. 4.79, p<0.001) and the group older than 70 years old (5.26 vs. 4.55, p<0.001). Likewise, we found for TSH values and FT3/FT4 ratio a significant difference (p <0.001) between different age groups.ConclusionsThe establishing RIs for the population of the Republic of Srpska were significantly differed from the recommended RIs by the manufacturer for TSH and FT4. Our results encourage other laboratories to develop their own RIs for thyroid parameters by applying CLSI recommendations.