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Centrifugation separates particles within the specimen according to their shape, dimensions, and density and basically can be defined as a separation method. The centrifuge is an essential device in medical laboratories to prepare the serum, plasma, and urine samples for analysis. It is basically an electric device composed of the stationary (motor) and the motile (rotor) part. The centrifugation depends on two main variables: relative centrifugal force (RCF) and centrifugation time. The physical impact separating the specimen into its components in the centrifuge known as RCF is expressed as the multiples of gravitational acceleration (×g). RPM, defined as the number of rotations of the centrifuge per minute, shows the speed of the centrifuge. RCF value can be calculated by using RPM, and the centrifuge radius. Because models and sizes of centrifuges vary considerably, the use of gravity (g) forces instead of RPM is suggested. The centrifuges can be classified according to their usage, speed, technical specifications, and rotor type. An accurate and precise centrifugation process is essential to prevent errors in the preanalytical phase. The purpose of this document is to ensure the standardization of a good, precise protocol for the centrifugation process among the medical laboratories.

Objective: In this study, we firstly aimed to determine components of biological variations (BVCs) in levels of glucose and glycated hemoglobin (HbA1c) in detail based on guidance from relevant organizations and experts. We also investigated whether reference intervals for both analytes were useful for evaluations, particularly consecutive test results. Methods: The study group consisted of 36 healthy volunteers. Samples were collected from each individual 4 times every 2 weeks for 45 days. All samples were assayed in duplicate within a single run. Finally, we estimated BVCs and the analytical performance specifications of both analytes. Results: Our results were fairly compatible with current biological variations (BVs) in both analytes reported in a database. It was calculated as within biological variation (CVI)=4.2% and between-subject variation (CVG)=5.3% for glucose while calculating as CVI=1.7% and CVG=4.5% for HbA1c. According to these results, the index of individuality (II) of glucose was higher than 0.6 while HbA1c’s II was lower than this value. Conclusion: We thought that guidelines from relevant international organizations should be followed to standardize the study design and to appropriately calculate BVCs for any analyte in BV studies. Finally, reference change value should be used to evaluate meaningful differences in HbA1c levels instead of reference interval.

Objective:In this study, we investigated the correlation between coronary lesion complexity as characterized by syntax score (SS) with circulating adiponectin and adipocyte-fatty acid binding protein (A-FABP4) concentrations in the presence of stable coronary artery disease affecting three coronary vessels (three-vessel stable CAD).Methods:The study groups consisted of 41 control subjects (28 males and 13 females, non-CAD group) and 115 affected subjects (79 males and 36 females, three-vessel stable CAD group). We divided into tertiles the three-vessel stable CAD group according to SS and estimated circulating concentrations of adiponectin and A-FABP4.Results:We did not find any correlation between the coronary lesion complexity with either the adiponectin and/or A-FABP4. We found lower the A-FABP4 of the non-CAD group than those of the groups with three-vessel stable CAD (pConclusion:Adiponectin is not a suitable parameter for demonstrating the existence of CAD or predicting coronary lesion complexity. A-FABP4 is more useful for the proof of the presence of CAD but A-FABP4 are not correlated with the severity of CAD.

Introduction:The aim of our study was to investigate the vascular endothelial growth factor levels in joint swelling-positive and joint swelling-negative rheumatoid arthritis patients and to then examine the relationship between conventional parameters such as the erythrocyte sedimentation rate and the levels of C-reactive protein, rheumatoid factor, and anti-cyclic citrullinated protein.Methods:Fifty-nine (52 women and seven men) rheumatoid arthritis patients and 25 (20 women and five men) healthy individuals volunteered for this study. The patient group was divided into two sub-groups based on whether or not they exhibited joint swelling.Results:The levels of vascular endothelial growth factor in the joint swelling-negative group were significantly different from those in the joint swelling-positive group, but they were not different from those in the control group (p=0.001 and p=0.72, respectively). We investigated the correlation between vascular endothelial growth factor and C-reactive protein levels (r=0.37, p=0.001). We also evaluated the diagnostic adequacy of vascular endothelial growth factor and created a ROC curve. The area under the curve was calculated to be 0.767.Conclusion:Vascular endothelial growth factor is an adequate diagnostic biomarker and can successfully be used to predict the occurrence of rheumatoid synovitis based on local inflammation.

Objective:Gastric cancer is one of the most common malignancies worldwide. The risk factors for gastric cancer include environmental and genetic factors. Inflammation and the immune system are known to contribute to the development of the gastric cancer. We examined the influence of critical polymorphisms of CTLA-4 and CD28 genes and circulating protein levels on the etiology of gastric cancer.Methods:Genotyping of SNPs was performed in 55 gastric cancer patients and 105 healthy individuals using the PCR-RFLP method, and circulating levels of sCTLA-4 and sCD28 were measured.Results:There were no significant differences in the genotype and allele distributions of the evaluated SNPs [CTLA-4-318 C>T (rs5742909), CTLA-4+49 A>G (rs231775), CD28 C>T (rs3116496)] between gastric cancer patients and controls (p=0.36, p=0.78, and p=0.80, respectively). The circulating levels of sCTLA-4 and sCD28 were significantly different between the gastric cancer group and the control group (pConclusion:The present results suggest that the CTLA-4 and CD28 gene polymorphisms that were evaluated do not play an important role in Turkish patients with gastric cancer. However, sCTLA4 and sCD28 levels were higher in cancer patients and may be useful as an auxiliary parameter in the diagnosis and monitoring of gastric cancer.

The presence of a chronic inflammatory state has also been widely documented in end-stage renal disease patients receiving maintenance hemodialysis (HD). It is commonly attributed to the constantly renewed activation of circulating neutrophils and monocytes following blood passage through dialysis circuits and subsequent generation of activated complement components due to contact of plasma with bioincompatible membranes and/or transfer of endotoxins from the dialyzate to the blood compartment. This conjunction leads to a massive generation of reactive oxygen species (ROS), for example, superoxide anion, hydrogen peroxide, hydroxyl radical, and chlorinated oxidants, such as hypochlorous acid by activated neutrophils. The exquisite vulnerability of proteins to ROS is now well documented. Oxidation of amino acid residues, such as tyrosine, leads to the formation of dityrosine, protein aggregation, cross-linking, and fragmentation. Dityrosine-containing protein cross-linking products in the plasma of dialysis patients are named as advanced oxidation protein products (AOPP). In addition, advanced glycation end-products (AGE) is a protein carbonyl compound and produced by protein–ROS interaction. We investigated both the effect of the renewed activation of the immune cells, due to blood–dialyzer interaction over protein oxidation products like AOPP and AGE, among chronic renal failure (CRF) patients receiving maintenance HD, and choice of dialyzers like high flux or the other group on protein oxidation product levels.