Background: Diagnosis of vitamin B12 deficiency is generally based on the measurement of serum vitamin B12 levels. However, in selected cases functional indices of vitamin B12, such as methylmalonic acid (MMA) and homocysteine (HCY), are needed. Here we compare the performance of four automated total vitamin B12 assays and also investigate how these assays relate to functional indices of vitamin B12 status. Methods: Total vitamin B12, MMA and HCY were measured in 69 serum samples from routine vitamin B12 assay requests. Serum vitamin B12 analysis was performed using four different immunoassay autoanalyzers: DxI 800 Unicel (Beckman Coulter, USA), ADVIA Centaur XP (Siemens Diagnostics, Tarrytown, NY, USA), Roche Cobas E601 (Roche Diagnostics, Germany), Architect i2000sr (Abbott Laboratories, Abbott Park, IL, USA). Serum MMA levels were determined by liquid chromatography-mass spectrometry (LC-MS) and serum homocysteine levels were determined by high pressure liquid chromatography (HPLC) methods. Results: Four immunoassay methods were comparable and correlated with each other. Correlation coefficients (r) ranged from 0.898 to 0.987, p<0.001. Highest correlation was observed between Roche Cobas – Architect i2000sr and poorest correlation was observed between DxI 800 Unicel – ADVIA Centaur comparison. DxI 800 Unicel assay demonstrated high mean bias [–122 pg/mL (–616–125 pg/mL)] and a concordance correlation coefficient (CCC) of 0.9161, lower than the others. MMA and HCY were correlated with the vitamin B12 results. The correlation coefficients with their 95% CI indicated that there was no statistically significant difference between the four methods according to their relationship with MMA and HCY. Conclusions: Total B12 assays correlate very well with each other. However, results of DxI 800 Unicel were lower compared to the other three autoanalyzers. All total vitamin B12 methods show similar relationships with HCY and MMA. Standardization of serum vitamin B12 assays is still not completed and further standardization studies are needed. Laboratory professionals and clinicians should be aware of this disagreement between assay methods and they should use these tests as ancillary tests.

Objective. The aim of the present study was to investigate whether pentraxin 3 (PTX3) can be a new noninvasive marker for prediction of liver fibrosis in patients with NAFLD. We also aimed to evaluate the relationship between PTX3 and atherosclerosis in patients with NAFLD.Method. Fifty-four male patients with biopsy-proven NAFLD and 20 apparently healthy male volunteers were included. PTX3 levels were determined, using an ELISA method (R&D Sysytems, Quantikine ELISA, USA). To detect the presence of subclinical atherosclerosis in NAFLD, measurements of CIMT, FMD, and cf-PWV levels were performed.Results. PTX3 levels in NAFLD patients with fibrosis were higher than both NAFLD patients without fibrosis and controls (P=0.032andP=0.028, respectively), but there was no difference between controls and NAFLD patients without fibrosis in terms of PTX3 levels (P=0.903). PTX3 levels were strongly correlated with cf-PWV (r=0.359,P=0.003), whereas no significant correlation was found with other atherosclerosis markers, CIMT and FMD.Conclusion. Elevated plasma PTX3 levels are associated with the presence of fibrosis in patients with NAFLD, independently of metabolic syndrome components. This study demonstrated that for the first time there is a close association between elevated PTX3 levels and increased arterial stiffness in patients with NAFLD.

Angiogenesis is the process of generating new blood vessels from preexisting vessels and is considered essential in many pathological conditions. The purpose of the present study is to evaluate the effect of aspartame on angiogenesis in vivo chick chorioallantoic membrane (CAM) and wound-healing models as well as in vitro 2,3-bis-2H-tetrazolium-5-carboxanilide (XTT) and tube formation assays. In CAM assay, aspartame increased angiogenesis in a concentration-dependent manner. Compared with the control group, aspartame has significantly increased vessel proliferation (p < 0.001). In addition, in vivo rat model of skin wound-healing study showed that aspartame group had better healing than control group, and this was statistically significant at p < 0.05. There was a slight proliferative effect of aspartame on human umbilical vein endothelial cells on XTT assay in vitro, but it was not statistically significant; and there was no antiangiogenic effect of aspartame on tube formation assay in vitro. These results provide evidence that aspartame induces angiogenesis in vitro and in vivo; so regular use may have undesirable effect on susceptible cases.

BACKGROUND:Angiogenesis is the formation of new blood vessels from pre-existing vasculature. Many factors and substances may stimulate angiogenesis and exhibit proliferative effect. In this study, we aimed to investigate the angiogenic and proliferat...

Patients with Klinefelter Syndrome (KS) have increased cardiometabolic risk however the pathogenesis is not clear. We investigated the presence of endothelial dysfunction, insulin resistance and inflammation in an unconfounded population of KS. A total of 32 patients with KS (mean age 21.59 ± 1.66 years) and 33 healthy control subjects (mean age: 22.15 ± 1.03 years) were enrolled. The demographic parameters, Asymmetric dimethylarginine (ADMA), homeostatic model assessment of insulin resistance (HOMA–IR) index and high–sensitivity C–reactive protein (hs–CRP) levels were measured. The patients had higher Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), insulin, HOMA–IR and ADMA levels (p < 0.001 for all) and lower High Density Lipoprotein Cholesterol (HDL–C) and total testosterone levels (p=0.002 and p<0.001, respectively), compared to the healthy controls. Total testosterone levels were significantly negatively correlated to ADMA (r = -0.479, p < 0,001), hs–CRP (r = -0.291, p = 0.034) and positively correlated to HDL–C (r = 0.429, p = 0.001) levels. The multivariate analysis has shown that total testosterone (β = -0.412, p = 0.001) and TG (β = 0.332, p = 0.009) levels were the significant independent determinants of the plasma ADMA levels. The results of the present study show that endothelial dysfunction and insulin resistance are prevalent even in the very young subjects with KS, who have no metabolic or cardiac problems at present. Also, hypogonadism seems to play an important role for increased cardiometabolic risk in patients with KS.