The Spectrum of Kidney Diseases in Children Associated with Low Molecular Weight Proteinuria.

BACKGROUND: Proteinuria, in addition to haematuria, is the most important laboratory parameter in patients with nephro-urological diseases. Low molecular weight proteinuria (LMWP) is of particular importance because some diseases genetic and tubulointerstitial are diagnosed based on its presence. AIM: The purpose of this study is to describe the clinical features, the course and outcome of pediatric patients with a renal disease associated with LMWP. MATERIAL AND METHODS: This retrospective observational study included 250 pediatric patients with various kidney diseases in which the type of proteinuria was defined by 4-20% gradient gel sodium dodecyl sulphate polyacrylamide gel (SDS-PAG) electrophoresis. RESULTS: Isolated LMWP was detected in 12% of patients, while mixed glomerulotubular proteinuria was detected in 18% of patients. It was detected in all patients with the Dent-1/2 disease, Lowe's syndrome and secondary Fanconi syndrome. Transient LMWP was also detected in a series of 12 patients with distal renal tubular acidosis. In patients with nephrotic syndrome, it was associated with corticoresistence and unfavourable clinical course. CONCLUSION: This study contributes to the understanding of the clinical spectrum of various kidney diseases associated with LMWP, their natural course, and the effect of therapy.

Incidental Detection of Dent-2 Disease in an Infant with Febrile Proteinuria.

OBJECTIVE: Febrile proteinuria is functional proteinuria and is seen as a transitory phenomenon during acute febrile illness, mainly viral infections. It is a benign phenomenon and clears promptly with resolution of the infection. CLINICAL PRESENTATION AND INTERVENTION: In this report, we present a patient who was thought to have febrile proteinuria. Persistence of significant proteinuria after resolution of the infection prompted biochemical and genetic workup which led to the diagnosis of Dent-2 disease. CONCLUSION: We recommend the use of SDS-PAGE (sodium dodecyl sulfate electropheresis) for the detection of low molecular weight proteinuria.

Cholesteryl ester transfer protein, low density lipoprotein particle size and intima media thickness in patients with coronary heart disease.

Cholesteryl ester transfer protein (CETP) plays a key role in reverse cholesterol transport and high density lipoprotein (HDL) metabolism. Predominance of small, dense LDL particles is associated with an increased risk of atherosclerosis and coronary heart disease (CHD).The aim of the study was to determine the potential relationship between the CETP concentration and low density lipoprotein (LDL) particle size and their association with intima media thickness (IMT) in patients with CHD. Lipid parameters, CETP concentration and LDL particle size were determined in 100 healthy subjects (control group) and in 100 patients with CHD, aged 43 to 77 years. Plasma CETP concentrations were measured by an enzyme-linked immuno-sorbent assay with two different monoclonal antibodies. LDL subclasses were separated by nondenaturing polyacrilamide 3-31% gradient gel electrophoresis. CETP concentration was higher in patients compared to controls (2.02 ± 0.75 mg/ml vs. 1.74 ± 0.63 mg/ml, p<0.01). Mean LDL particle size (nm) was significantly smaller in patients than in controls (24.5 ± 1.1 vs. 26.1 ± 0.9; p<0.001). There was no relation between LDL particle size and CETP concentration (r=-0.1807, p=0.072). Age, diastolic blood pressure, CETP concentration and LDL particle size were independent factors for determing IMT by multiple linear regression analysis. They accounted for 35.2 % of the observed variability in IMT. CETP is not an independent contributor of LDL particle size. CETP might play a role in determining lipoprotein distributions, but did not seem to be the sole factor in the formation of small LDL particles.

Bioluminescence determination of enzyme activity of firefly luciferase in the presence of pesticides.

Firefly luciferase (EC 1.13.12.5) (FL) is the key enzyme in the firefly bioluminescence method (FB), which is widely used to determine the viability of living cells. The FB method can also be applied to monitoring the influence of different pollutants, such as pesticides. Firefly luciferase is a hydrophobic enzyme and its activity depends on the type of solvent, pH and substances present in the reaction mixture. The influence of three aromatic pesticides, including fenoxaprop-p-ethyl (I), diclofop-methyl (II) and metsulfuron methyl (III), on the enzyme activity was indirectly evaluated through the measurement of emitted light in the bioluminescence reaction, expressed in relative luminescence units (RLU). The reaction mixture used in the bioluminescence measurements consisted of: Tris buffer (pH 7.75), adenosine triphosphate (ATP) and ATP monitoring reagent, where FL is present. Ethanol-water solutions of each pesticide were then added at concentrations of 2.4 x 10(-4)-2.4 x 10(-8) mol/L. The FL activity inhibition factors (FL In%) were determined. The FL activity was maximally inhibited in the presence of all pesticides under study at a concentration of 2.4 x 10(-4) mol/L and was lowered by about 15-26% for pesticide I at concentrations of 2.4 x 10(-5)-2.4 x 10(-8) mol/L, whereas pesticides II and III, applied in the same concentration range, showed smaller FL inhibition values (5.3-20%). The pesticide degradation products (obtained after a 1 month period), measured in the same experimental conditions, in most cases exhibited a much less inhibitory effect on the enzyme activity than the corresponding initial pesticide.

Distribution of low density lipoprotein subclasses in Macedonian children.

BACKGROUND: Current reports claim that small and dense LDL particles are more atherogenic than larger LDL particles. There are many studies presenting LDL subclass distribution in adults, but there is not enough data regarding children in the literature on this problem. The aim of our study was to examine LDL subclass distribution in healthy children in the Republic of Macedonia. MATERIALS/METHODS: Plasma LDL subclasses in 100 children aged 9-18 years were analyzed using non-denaturing polyacrilamide gradient (3-31%) gel electrophoresis. Conventional plasma lipid and apoprotein parameters thought to be related to LDL size were determined as well. RESULTS: The results obtained showed the prevalence of large LDL subclasses (phenotype A) in 89% of the children, whereas small LDL subclasses (phenotype B) were observed in 11%. The mean LDL size was 26.37 +/- 0.68 nm, and there was no difference between gender groups. No association was noted between LDL size and plasma lipid and apoprotein levels, age, or BMI. CONCLUSIONS: LDL size and distribution is not gender- or age-dependent, or influenced by plasma lipid and apoprotein concentrations in childhood. This suggests that analysis of LDL subclass phenotype may provide better information on the risk of atherosclerosis development in adulthood.

LDL and HDL subclass distribution in patients with end-stage renal diseases.

OBJECTIVES: To examine the alterations in LDL and HDL subclass distribution in ESRD patients compared with a control group and to investigate the relationship of LDL particle size to the other plasma lipoproteins levels. DESIGN AND METHODS: Plasma lipids, LDL and HDL subclasses were determined in 63 hemodialysis patients (HD), 42 predialysis patients and 345 control subjects. Lipoprotein subclasses were separated by polyacrylamide 3 to 31% gradient gel electrophoresis. RESULTS: In predialysis group, 88% subjects had small LDL particles compared with 58.5% of hemodialysis patients and 16.5% of control subjects. Mean LDL size particle diameter was significantly smaller in HD and predialysis patients in comparison with controls (p < 0,0005, p < 0,0001; respectively). Significant inverse correlation between LDL particle size and triglyceride level was observed for both patient groups. Decreased levels of the largest HDL2b subclass was found in both predialysis (16.5%) and in HD patients (30%) as compared with controls (50%), and increased levels of the small HDL3a subclass was found only in predialysis group (21%) in comparison with controls (4.5%). CONCLUSIONS: Alterations in LDL and HDL subclass distribution toward smaller particles is the main lipid abnormality associated with atherogensis found in ESRD. ESRD is associated with reduced levels of HDL2b subclass and increased levels of HDL3c subclass, which occurs in coronary artery disease (CAD) as well.

Low density lipoprotein particle size phenotyping in healthy persons and patients with myocardial infarction.

AIM: To determine distribution, size, and phenotype of low density lipoprotein (LDL) subclasses and examine the influence of plasma lipid concentrations on lipoprotein particle size in both healthy population and patients with myocardial infarction. METHOD: Nondenaturing gradient (3-31%) gel electrophoresis for lipoprotein separation was used to determine the distribution and size of LDL subclasses in 132 patients with myocardial infarction and 334 healthy control subjects. RESULTS: Large LDL subclasses (LDL1, LDL2, phenotype A) were dominant in 88.5% of the healthy population, whereas in most patients with myocardial infarction (81%) the dominant subclasses were LDL3 and LDL4 (phenotype B). Only 19% of the patients belonged to the phenotype A (LDL1 and LDL2). Mean LDL subclass size (nm) was significantly smaller in patients with myocardial infarction than in controls (24.381.07 nm vs 25.940.89 nm; p<0.001). In both groups, LDL size was independent of LDL plasma cholesterol but associated with high triglyceride plasma concentrations. CONCLUSION: Coronary artery disease is associated with the predominance of small LDL particles and high plasma triglyceride concentrations. The risk of development of cardiovascular disease can be assessed more accurately by determining lipoprotein subclasses.

Gradient gel electrophoretic separation of LDL and HDL subclasses on BioRad Mini Protean II and size phenotyping in healthy Macedonians.

BACKGROUND: Lipoprotein subclass determinations provide a more detailed reflection of lipoprotein metabolism and an accurate prediction for risk of cardiovascular disease. Gradient gel electrophoresis for lipoprotein separation on Pharmacia electrophoretic apparatus has been most commonly used for many years. METHODS: In this paper, we describe a new method for separating LDL and HDL subclasses by nondenaturing polyacrylamide gradient (3-31%) gel electrophoresis, using BioRad Mini Protean II electrophoretic cells. RESULTS: The mean particle diameters of cholesterol-stained LDL and HDL lipoproteins were estimated after calibrating the gels with size standards, using fractional absorbance profiles. For the first time in the Republic of Macedonia, lipoprotein distribution and size phenotyping were studied in 345 healthy individuals. Large LDL subclasses (phenotype A) were dominant in 88.5% of the population, whereas small LDL subclasses (phenotype B) were dominant in 11.5%. The mean dominant LDL size was 26.08+/-0.8 nm. Five HDL subclasses were separated on the same gels, and HDL2b and HDL2a (larger) were dominant in healthy Macedonians. CONCLUSION: Antiatherogenic, larger LDL and HDL particles are most commonly found in healthy populations in the Republic of Macedonia.