Onder Sirikci

Macroprolactin does not contribute to elevated levels of prolactin in patients on renal replacement therapy

Objective  Three molecular forms of PRL with molecular weights of 23, 50–60 and > 100 kDa have been defined. The high‐molecular‐weight forms are called macroprolactin. Different immunoassays produce varyingly elevated results with macroprolactin‐containing sera. The kidneys are reported to clear 25% of PRL from the circulation. Hyperprolactinaemia is seen in 20–75% of patients with chronic renal failure (CRF). PRL clearance rate has been reported to be reduced in CRF and the resulting hyperprolactinaemia is due to reduced renal function.

Serum Erythropoietin, Insulin-like Growth Factor 1, and Vascular Endothelial Growth Factor in Etiopathogenesis of Retinopathy of Prematurity

BACKGROUND AND OBJECTIVE The role of growth factors in the pathogenesis of retinopathy of prematurity (ROP) is known. To better understand this issue, the authors investigated vascular endothelial growth factor (VEGF), insulin-like growth factor 1 (IGF-1), and erythropoietin (EPO) levels in the cord blood of premature newborns. PATIENTS AND METHODS IGF-1, VEGF, and EPO levels were measured in cord blood samples obtained from 93 infants less than 32 weeks of gestational age at birth, and their predictive value in the development of ROP was investigated. RESULTS The mean birth age and mean birth weight were 32.2 ± 1.5 weeks and 1,678 ± 326 g, respectively, in infants without ROP and 29.6 ± 2.3 weeks and 1,384 ± 343 g, respectively, in infants with ROP. Multivariate logistic regression analysis showed that only the gestational age and the serum VEGF at birth were independently associated with the risk of developing ROP (P = .002, Exp[B] = 0.514, CI = 95%: 0.341-0.775; P = .028, Exp[B] = 0.999, CI = 95%: 0.997-1.00). CONCLUSION Serum VEGF levels at birth were lower in infants who later developed ROP. This may have a predictive value for ROP and contribute to the pathogenesis, because affected infants may be more susceptible to extrauterine hyperoxic insult.

Prevention of Atherosclerosis by α-Tocopherol in Smooth Muscle Cells by a Mechanism Involving Signal Transduction Modulation

α-Tocopherol, the biologically most active form of Vitamin E, decreases in a concentration dependent way, proliferation of smooth muscle cells. At the same concentrations (10 – 50 μM) it induces inhibition of protein kinase C activity. Proliferation and protein kinase C inhibition by α-tocopherol, the lack of inhibition by β-tocopherol and the prevention by s-tocopherol indicate that the mechanism involved is not related to the radical-scavenging properties of these two molecules, which are essentially equal. All-rac-α-tocopherol is less potent than RRR-α-tocopherol on smooth muscle cell proliferation. probucol (10 – 50 μM), a potent lipophilic antioxidant, does not inhibit smooth muscle cell proliferation and protein kinase C activity. In rabbit studies, atherosclerosis was induced by a 2% cholesterol-containing, vitamin E poor-diet. Six different groups of rabbits each were received vitamin E, probucol; probucol plus vitamin E. After 4 weeks, aortas were analysed for protein kinase C activity. Their media smooth muscle cells exhibited an increase in protein kinase C activity. Vitamin E fully prevented cholesterol induced atherosclerotic lesions and the induction of protein kinase C activity. Probucol was not effective in preventing both cholesterol induced atherosclerotic lesions and the induction of protein kinase C activity. These results show that the protective effect of vitamin E against hypercholesterolemic atherosclerosis is not produced by an other antioxidant such as probucol and therefore may not be linked to the antioxidant properties of this vitamin. The effects observed at the level of smooth muscle cells ex-vivo and cell culture suggest an involvement of signal transduction events on the onset of atherosclerosis. It is at this level that the protective effect of vitamin E against atherosclerosis is exerted.

Abnormal gel flotation in a patient with apperant pneumonia diagnosis: a case report.

Introduction: Serum blood collection tubes with separator gel are widely used by many laboratories for chemistry analyses. We describe a case of a primary blood collection tube filled with blood sample and a floating separator gel. Materials and methods: The blood sample was collected from a 51 years old female in intensive care unit with the diagnosis of pneumonia into a BD Vacutainer SST tube (Becton Dickinson, NJ, USA) containing serum separator gel and conveyed to the core laboratory of Marmara University Hospital within 30 minutes from collection. Sample was immediately centrifuged at room temperature at 1500 × g for 10 minutes. Results: The analyses revealed a highly increased total protein concentration of 145 g/L (reference interval 64–83 g/L). The nephelometric analyses showed an elevated serum IgG concentration of 108 g/L (reference interval 6.5–16 g/L) and IgG lambda monoclonal band was determined by serum immunofixation electrophoresis. Conclusion: Limitation of the separator gel tubes in patients with a high plasma density and its possible effects on test results and laboratory costs should be remembered. The clinical diagnosis stated in the information system should also reveal known comorbid conditions besides the apparent admission reason. This information would avoid resampling, additional testing, and communication efforts with the clinicians.

The effect of different protease inhibitors on stability of parathyroid hormone, insulin, and prolactin levels under different lag times and storage conditions until analysis

Proteolytic cleavage through proteases affects peptide hormone levels, which is of particular significance when the time interval between sampling and analysis is prolonged. We evaluated the stability of parathyroid hormone, insulin, and prolactin molecules (i) with different protease inhibitors such as K2EDTA, aprotinin, and protease inhibitor cocktail (PIC), (ii) with different lag times (6‐72 hours), and (iii) under different storage temperatures (4°C vs room temperature [RT]) until analysis.

Have You Ever Seen a 21-mmol/L Serum K+ Concentration?

A blood sample from an 82-year-old man with non-Hodgkin lymphoma was analyzed. His chemistry results are shown in Table 1. The serum hemolysis index was negative. View this table: Table 1. Chemistry results. 1. What can cause spurious gross hyperkalemia? 2. What is the most likely type of preanalytical error involved in …