Metin Uyanik

Comparison of 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels using mass spectrometer and urine albumin creatinine ratio as a predictor of development of diabetic nephropathy.

Abstract Background. Measurement of urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) has recently become more popular as a means of assessing oxidative stress in the human body. The aim of this study is to compare the levels of urine 8-OHdG in patients with type 2 diabetes with and without nephropathy and to evaluate its role as a biochemical marker for distinguishing these patients from healthy and patients without complications. Methods. For this purpose, 52 patients with type 2 diabetes mellitus (32 with nephropathy (DMN), 20 without nephropathy (DM)) and 20 healthy control subjects (C) were included in this study. The urine concentrations of 8-OHdG were measured by modified LC-MS/MS method and compared with the first morning voiding urine albumin/creatinine ratio (UACR) and HbA1c values of the same patients. Results. The concentrations of urine 8-OHdG in DMN and DM patients were higher than those of the control subjects (3.47 ± 0.94, 2.92 ± 1.73, 2.1 ± 0.93 nmol/mol creatinine, respectively). But there was no statistical difference between DMN and DM (p = 0.115). There is significant correlation between urinary 8-OHdG and UACR (r = 0.501, p < 0.001). According to ROC analysis, the AUC value of HbA1c was higher than the value of the AUC of 8-OHdG (0.882 and 0.771, respectively). Conclusions. This study shows that the urine 8-OHdG levels increase in diabetic patients. However, urinary 8-OHdG is not a useful clinical marker, compared with UACR, to predict the development of diabetic nephropathy in diabetic patients.

Comparison of plasma and erythrocyte membrane fatty acid compositions in patients with end-stage renal disease and type 2 diabetes mellitus

BACKGROUND In this study, we aimed to compare the serum lipid profile and fatty acid (FA) compositions of erythrocyte membrane (EM) and plasma in three different patient groups (group 1: type 2 diabetes mellitus (T2DM)+end-stage renal disease (ESRD), group 2: ESRD, group 4: T2DM) and healthy controls (group 3) simultaneously. METHODS 40 ESRD patients treated with hemodialysis (HD) in Gulhane School of Medicine (20 with T2DM) and 32 controls (17 with T2DM, 15 healthy controls) were included in the study. Plasma and EM FA concentrations were measured by gas chromatography-flame ionization detector (GC-FID). RESULTS Plasma and EM palmitic acid (PA) and stearic acid (SA) levels were significantly higher in T2DM patients compared to controls (p=0.040 and p=0.002 for plasma, p=0.001 and p=0.010 for EM, respectively). EM docosahexaenoic acid (DHA) levels were also significantly lower in patients with ESRD+T2DM and ESRD compared to controls (p=0.004 and p=0.037, respectively). CONCLUSIONS Patients with insulin resistance display a pattern of high long chain saturated FAs (PA, SA and arachidic acids). However, while there are no recognized standards for normal EM DHA content, decreased levels of EM DHA in ESRD patient groups (groups 1 and 2) suggest that there may be reduced endogenous synthesis of DHA in HD subjects, due to the decreased functionality of desaturase and elongase enzymes. Because membrane PUFA content affects membrane fluidity and cell signaling, these findings are worthy of further investigation.

Neutrophil-lymphocyte ratio is useful for the prognosis of patients with hepatocellular carcinoma

There is increasing evidence that neutrophil-lymphocyte ratio (NLR) may play a role in predicting recurrence in patients with hepatitis B virus-related hepatocellular carcinoma (HCC) after liver transplantation. In the original study by Yan et al, it was aimed to determine whether an elevated NLR is associated with tumor recurrence. Total tumor size (> 9 cm) and macro-vascular invasion were found to be more significant than NLR according to the multivariate logistic regression analysis. Therefore, substantive significance should be emphasized rather than NLR because total tumor size and macro-vascular invasion are easier and more expressive than NLR in assessing HCC recurrence. NLR and platelet-lymphocyte ratio (PLR) are markers which are easy to obtain and can be used as inflammation indicators. Moreover, assessment of both NLR and PLR may add some value as a good predictor of risk for post-liver transplantation HCC recurrence. However, while the study was constructed on whole blood analysis, further details about the features and performance characteristics of the whole-blood analyzer, and preanalytical/analytical variables should also be mentioned.

Comparison of blood gas, electrolyte and metabolite results measured with two different blood gas analyzers and a core laboratory analyzer

Abstract Background. Blood gas analyzers (BGAs) are important in assessing and monitoring critically ill patients. However, the random use of BGAs to measure blood gases, electrolytes and metabolites increases the variability in test results. Therefore, this study aimed to investigate the correlation of blood gas, electrolyte and metabolite results measured with two BGAs and a core laboratory analyzer. Methods. A total of 40 arterial blood gas samples were analyzed with two BGAs [(Nova Stat Profile Critical Care Xpress (Nova Biomedical, Waltham, MA, USA) and Siemens Rapidlab 1265 (Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA)) and a core laboratory analyzer [Olympus AU 2700 autoanalyzer (Beckman-Coulter, Inc., Fullerton, CA, USA)]. The results of pH, pCO2, pO2, SO2, sodium (Na+), potassium (K+), calcium (Ca+ 2), chloride (Cl−), glucose, and lactate were compared by Passing-Bablok regression analysis and Bland-Altman plots. Results. The present study showed that there was negligible variability of blood gases (pCO2, pO2, SO2), K+ and lactate values between the blood gas and core laboratory analyzers. However, the differences in pH were modest, while Na+, Cl−, Ca2+ and glucose showed poor correlation according to the concordance correlation coefficient. Conclusions. BGAs and core laboratory autoanalyzer demonstrated variable performances and not all tests met minimum performance goals. It is important that clinicians and laboratories are aware of the limitations of their assays.

Accurate use of neutrophil/lymphocyte ratio from the perspective of laboratory experts

Dear editor I read with great interest the recent published article “Neutrophil/lymphocyte ratio in patients with atrial septal aneurysm” by Demir and Demir.1 In this study, researchers compared the neutrophil/lymphocyte ratio (NLR) between patients with atrial septal aneurysm (ASA) and controls. It was reported that patients with ASA have higher NLR compared with controls.1 There are some points that we would like to address from this study. Firstly, a white blood cell (WBC) count of more than 12,000 cells per μL, or less than 4,000 cells per μL, was mentioned as one of the exclusion criteria.1 However, the authors did not state why these values were used as the limits for inclusion. Whether a WBC count of more than 12,000 cells per μL is accepted as an indicator of inflammation or infection is unclear, and there is no mention of the literature that this value is based on, or which device (brand/model) was used for the WBC count. The WBC reference ranges may vary depending on many factors such as the population studied, the individual laboratory, and the instruments (eg, types of collection tubes) or measurement methods used (eg, waiting period prior to analysis).2,3 Secondly, despite comparing groups based on neutrophil and lymphocyte counts, there was no exclusion criteria specified for these parameters. According to Horne et al,4 and as stated in the study,1 high neutrophil, monocyte, and NLR counts, as well as low lymphocyte counts, are independently related to increased cardiovascular events. However, in this study, Table 2 shows an increased total lymphocyte count (TLC) in controls (2,911±837 cells per mm3) draws attention rather than the low TLC of patients (1,862±625 cells per mm3).1 A TLC significantly higher than 2,900 lymphocytes in a μL of blood is generally considered to be an indicator of lymphocytosis in adults.3 If you accept 2,900 cells per mm3 as the upper limit of the TLC, the differential diagnosis of lymphocytosis should be given to the controls included in the study. However, in several other sources 4,000 cells per mm3 is regarded as the upper limit of the TLC.5,6 Additionally, although the TLC obtained from the patient group was relatively lower than in the control group, all results were within the reference values.3 Therefore, it would not be correct to declare that the patient group had a low TLC. On the basis of this information, evaluation of the percentage of lymphocytes and neutrophils may also be important in patient groups with borderline TLC values. Automated blood counting instruments should provide percentage values for each type of WBC count. Thirdly, the measurement of NLR was suggested as an indicator of increased risk of arrhythmia, based on the association found between ASA and NLR in the study, however the physiopathological causes supporting this conclusion were not thoroughly discussed.1 NLR has been used frequently to predict outcomes in patients with cancer and coronary artery disease.7,8 Systemic inflammation is thought to be a risk factor for cardiovascular disease, and NLR, which integrates the detrimental effects of neutrophilia (an indicator of inflammation) and lymphopenia (an indicator of physiological stress), has emerged as a useful prognostic marker.8 Possible causes affecting neutrophil/lymphocyte counts and the confounding factors which have a considerable effect on the clinical availability of NLR should be discussed in more detail in this study population. Finally, NLR itself alone without other inflammatory markers may not accurately provide information about the prognosis of the patients. There are studies evaluating soluble P- and E-selectin, interleukin-6, and high-sensitivity C-reactive protein (hs-CRP) as indices of prothrombogenic and proinflammatory activity in a similar group of patients.9,10 While assessing the predictive values of parameters like NLR (derived from the ratios), and comparing them for validity and accuracy, proven markers will provide more reliable results every time. In conclusion, the types of collection tubes, waiting period prior to analysis, instrumental parameters and reference ranges for each parameter must be specified as they are easily affected by analytical and preanalytical variables in studies based on laboratory results.11

Is increased red cell distribution width an indicating marker of nonalcoholic steatohepatitis and fibrotic stage

Red cell distribution width (RDW) may play an important role in predicting steatohepatitis and liver fibrosis. In the original study, it was aimed to determine whether RDW could be used for this purpose or not. There are studies indicating that higher RDW is correlated well with components of metabolic syndrome. Because nonalcoholic fatty liver disease is now recognized as the hepatic manifestation of metabolic syndrome, possible impact of the accompanying confounders on the study findings should have been detailed. There may be a patient selection bias due to use of improper cut-off values for alcohol consumption and inclusion of only subjects with normal aminotransferase levels and normal abdominal ultrasonography. Patients without hepatosteatosis on ultrasonography and with any restriction of aminotransferase levels should have been included in the control group, because isolated aminotransferase elevation is not decisive in the diagnosis of hepatosteatosis. Although iron, vitamin B12 and folic acid deficiencies were included in exclusion criteria, functional forms of these molecules like methylmalonic acid, homocysteine, ferritin levels and total iron binding capacity, which are more sensitive and specific parameters for vitamin B12 and folic acid deficiencies, were not mentioned. Consequently, RDW, an inexpensive, non-invasive, but powerful indicator overlooked on whole blood analysis, itself without other inflammatory markers may not accurately provide information about progression of nonalcoholic steatohepatitis and fibrosis.

Freezing of Apheresis Platelet Concentrates in 6% Dimethyl Sulfoxide: The First Preliminary Study in Turkey.

Objective: Transfusion of platelet suspensions is an essential part of patient care for certain clinical indications. In this pioneering study in Turkey, we aimed to assess the in vitro hemostatic functions of platelets after cryopreservation. Materials and Methods: Seven units of platelet concentrates were obtained by apheresis. Each apheresis platelet concentrate (APC) was divided into 2 equal volumes and frozen with 6% dimethyl sulfoxide (DMSO). The 14 frozen units of APCs were kept at -80 °C for 1 day. APCs were thawed at 37 °C and diluted either with autologous plasma or 0.9% NaCl. The volume and residual numbers of leukocytes and platelets were tested in both before-freezing and post-thawing periods. Aggregation and thrombin generation tests were used to analyze the in vitro hemostatic functions of platelets. Flow-cytometric analysis was used to assess the presence of frozen treated platelets and their viability. Results: The residual number of leukocytes in both dilution groups was <1x106. The mean platelet recovery rate in the plasma-diluted group (88.1±9.5%) was higher than that in the 0.9% NaCl-diluted group (63±10%). These results were compatible with the European Directorate for the Quality of Medicines quality criteria. Expectedly, there was no aggregation response to platelet aggregation test. The mean thrombin generation potential of post-thaw APCs was higher in the plasma-diluted group (2411 nmol/L per minute) when compared to both the 0.9% NaCl-diluted group (1913 nmol/L per minute) and the before-freezing period (1681 nmol/L per minute). The flow-cytometric analysis results for the viability of APCs after cryopreservation were 94.9% and 96.6% in the plasma and 0.9% NaCl groups, respectively. Conclusion: Cryopreservation of platelets with 6% DMSO and storage at -80 °C increases their shelf life from 7 days to 2 years. Besides the increase in hemostatic functions of platelets, the cryopreservation process also does not affect their viability rates.

The role of urinary nerve growth factor for the diagnosis and assessment of the biofeedback success in children with dysfunctional voiding.

INTRODUCTION Dysfunctional voiding (DV) occurs in neurologically normal children who are not able to establish brain control on detrusor muscle contractions (DMCs). It is also reported to be the result of incorrect voiding habits during toilet training. Children contract pelvic floor muscles (PFMs) to suppress DMC and DV begins. Urinary nerve growth factor (uNGF) is necessary for the synthesis and regulation of neurotransmitters, development of dorsal root ganglia (sensory neurons), and development of sympathetic cells during embryonic and post-natal life. uNGF has also a role in the intracellular signal transduction in nerve cells towards the target organ. To our knowledge, no study has investigated the association between uNGF, biofeedback treatment and DV in children. OBJECTIVES The aim was to examine the potential effect of uNGF in the assessment of the effectiveness of biofeedback success in children with lower urinary tract disorders. STUDY DESIGN Fifty-two children with the suspicion of DV and 48 children from a primary school reporting no urinary complaints were enrolled in this study from October 2010 to April 2013 in the Urology Department. uNGF levels were compared. RESULTS The mean uNGF/creatinine (Cr) level was 0.23 ± 0.26 in the control group and 0.96 ± 0.88 in the DV group (p < 0.001). The mean uNGF/Cr levels in the DV group at baseline and at the end of biofeedback therapy at 6 and 12 months were 0.90 ± 0.78, 0.26 ± 0.32, and 0.40 ± 0.50, respectively (p < 0.001) (Figure). DISCUSSION To our knowledge this study is the first to show the correlations between uNGF levels and biofeedback therapy in children with DV. Tissue NGF in 12 patients with overactive bladder (OAB)/detrusor overactivity and 15 healthy women was previously compared and it was suggested that there was no correlation between bladder tissue NGF and OAB. uNGF levels in the bladder in patients with interstitial cystitis and idiopathic sensorial urgency were evaluated previously, and uNGF levels reported. Similar to these reports, most of the previous studies handled uNGF in patients with diseases such as interstitial cystitis, OAB, urinary tract infections, urolithiasis, spinal cord injury, and prostate cancer, and found significantly higher uNGF levels. These studies were generally in adults. A previous study about uNGF comprised 40 children with OAB, in contrast to other studies. According to this study, 40 children diagnosed with OAB were administered anti-muscarinic therapy (oxybutynin 0.3-0.5 mg/kg/day). It was reported that uNGF/Cr levels of the OAB group were higher than control group. In the current study, we evaluated the uNGF difference in DV and the effect of biofeedback treatment on uNGF levels. CONCLUSIONS uNGF levels were higher in children with DV and decreased after biofeedback therapy. uNGF levels could be used for the diagnosis and the assessment of biofeedback success in these children.

Accurate Use of Neutrophil to Lymphocyte Ratio in Predicting Prognosis of Papillary Thyroid Carcinoma

We read with great interest the recently published article by Lang et al. [1]. Their study evaluated the utility of a preoperative neutrophil to lymphocyte ratio (NLR) for determining disease-free survival (DFS) and for predicting occult central nodal metastasis (CNM) in patients with a cN0 papillary thyroid carcinoma (PTC). They concluded that there was no significant association between a high NLR and poor DFS or higher risk of occult CNM in cN0 PTC. We would like to share our thoughts about their study. First, they excluded some clinical conditions that might have affected the total and differential white blood cell (WBC) counts in an attempt to avoid possible confounders for the NLR. However, in studies aimed at determining predictive markers based on laboratory results, it might be better to identify a specific WBC count range within the exclusion criteria. It is well known that WBC reference ranges vary depending on such factors as the population studied, the individual laboratory performing the counts, the instruments (e.g., type of collection tube), and the measurement methods (e.g., waiting period prior to analysis) [2]. Determining a specific WBC count range and the clinical conditions likely to affect the WBC count could avoid possible bias during patient selection. Second, Lang et al. stated that patients were categorized into NLR tertiles: NLR \ 1.93, 1.93–2.79, and [2.79. Their results indicated that the mean (±SD) and median (range) for NLR were 2.68 ± 1.84 and 2.29 (0.52–16.6), respectively. The authors, however, did not refer to the literature to determine the NLR cutoff values. Various NLR cutoff values have been determined and used in other studies that focused on similar patient groups [3, 4]. Therefore, for the present study population it would be more appropriate to perform receiver operating characteristic analysis to determine the most appropriate cutoff values for the NLR. Third, systemic inflammation commonly occurs in the presence of many human cancers, including thyroid carcinoma. The NLR alone—without other inflammatory markers (e.g., C-reactive protein, erythrocyte sedimentation rate, tumor necrosis factor-a, interleukin 6)—may not accurately predict a patient’s prognosis [5]. In conclusion, instrumental parameters and reference ranges for each parameter must be specified as they are easily affected by analytical and preanalytical variables in studies based on laboratory results. Thus, when assessing a predictive value for a parameter such as the NLR (derived from ratios), proven markers can provide more reliable results.

Importance of the selected cut-offs for serum uric acid and lipids levels.

We read with great interest the recently published article “The prevalence of nonalcoholic fatty liver disease and relationship with serum uric acid level in Uyghur population” by Cai et al. [1]. Authors have investigated the prevalence of nonalcoholic fatty liver disease (NAFLD) and the association of serum uric acid (SUA) level with NAFLD in Uyghur people. They concluded that SUA level was significantly associated with NAFLD, and the prevalence rate of NAFLD increased with progressively higher SUA levels. However, we think that there are some points that should be emphasized about this study. Firstly, the cut-off value for fasting plasma glucose (FPG) was taken as 6.10 mmol/L in Table 5, while it was determined as 5.6 mmol/L in the section Diagnostic Criteria. Due to this difference, P value, determined by multivariate logistic regression analysis, may vary and even become meaningless while it was statistically significant. Secondly, since total cholesterol (TC) is defined as the sum of HDL-C, LDL-C, and VLDL-C, it has to be technically higher than LDL-C. However, in Table 5 the same regression cut-off values were used for TC and LDL-C. This improper preference may lead to incorrect results in regression analysis. In addition, as can be seen in Table 6, authors included three lipid parameters (TC, TG, and HDL-C) into the multivariate logistic regression analysis. However, since these parameters are tightly correlated with each other, results, especially odds ratio and Wald value, can easily be affected. Adding or removing only a single parameter to multivariate logistic regression analysis will change all of the results, due to the relative effect of each parameter. Thirdly, in many studies, different diagnostic criteria for hyperuricemia were used for males (>7 mg/dL or >420 μmol/L) and females (>6 mg/dL or >360 μmol/L), as indicated in the original study [2–4]. However, this distinction was not taken into consideration when comparing the NAFLD group with non-NAFLD group in Table 2. 42.8% of non-NAFLD and 72.4% of NAFLD patients were male. This big difference of 29.6% may be the reason for the statistical significance. When patients were divided according to the gender, this significance may not be seen. In conclusion, in multivariate logistic regression analysis included and removed parameters are highly important since the relative effect of each parameter is calculated in this analysis. It is also important to use the gender specific reference ranges for SUA.