Renal function outcomes after nephrectomy for kidney cancer in elderly patients

The kidneys are organs with multiple functions and essential to maintain life. Ablative procedures, such as nephrectomy, diminish nephron mass and can have a potentially negative impact on renal function. We investigated renal function outcome in patients who underwent nephrectomy for renal cell cancer with special emphasize on elderly patients. Data from 104 patients who underwent nephrectomy for kidney cancer in the Department of Urology, University Hospital Rijeka from January 2005 to December 2010 were retrospectively analyzed. All patients had a normal concentration of serum creatinine and a normal contralateral kidney before surgery. Renal function, as estimated by the glomerular filtration rate (eGFR), was determined before and after nephrectomy using the abbreviated Modification of Diet in Renal Disease equation. We compared the eGFR before and after nephrectomy in the patients of different age. The mean preoperative eGFR was 75.2 mL/min, and the mean postoperative eGFR was 52.7 mL/min (p < 0.0001). In the group of patients > or = 65 years old, the mean preoperative GFR was 69.2 mL/min, and the mean postoperative eGFR was 47.4 mL/min (p < 0.0001). Our data indicate that the eGFR significantly decreased after nephrectomy for kidney cancer. In elderly patients, diminished renal function following nephrectomy was more prominent.     

Membrane cholesterol content plays a key role in the neurotoxicity of β-amyloid: implications for Alzheimer's disease

Beta amyloid (βA) plays a central role in the pathogenesis of the most common and devastating neurodegenerative disorder, Alzheimer's disease (AD). The mechanisms of βA neurotoxicity remain controversial, but include dysregulation of calcium homeostasis and oxidative stress. A large body of data suggest that cholesterol plays a significant role in AD. In mixed cultures containing hippocampal neurons and astrocytes, we have shown that neurotoxic βA peptides (1-42 and 25-35) cause sporadic cytosolic calcium ([Ca(2+) ](c) ) signals in astrocytes but not in neurons, initiating a cascade that ends in neuronal death. We now show, using the cholesterol-sensitive fluorescent probe, Filipin, that membrane cholesterol is significantly higher in astrocytes than in neurons and mediates the selective response of astrocytes to βA. Thus, lowering [cholesterol] using mevastatin, methyl-β-cyclodextrin or filipin prevented the βA-induced [Ca(2+) ](c) signals, while increased membrane [cholesterol] increased βA-induced [Ca(2+) ](c) signals in both neurons and astrocytes. Addition of βA to lipid bilayers caused the appearance of a conductance that was significantly higher in membranes containing cholesterol. Increasing membrane [cholesterol] significantly increased βA-induced neuronal and astrocytic death. We conclude that a high membrane [cholesterol] promotes βA incorporation into membranes and increased [Ca(2+) ](c) leading to cell death.     

Presenilin-1 Delta E9 Mutant Induces STIM1-Driven Store-Operated Calcium Channel Hyperactivation in Hippocampal Neurons

Presenilins regulate calcium homeostasis in the endoplasmic reticulum, and dysregulation of intracellular calcium has been implicated in the pathogenesis of Alzheimer disease. Elevated presenilin-1 (PS1) holoprotein levels have been detected in postmortem brains of patients carrying familial Alzheimer disease (FAD) PS1 mutations. This study examines the effect of the FAD presenilin mutant that lacks the ninth exon (PS1 ?E9) and does not undergo endoproteolysis on store-operated calcium (SOC) entry. Significant enhancement of SOC channel activation was detected by electrophysiological measurements in hippocampal neurons with PS1 ?E9 mutant expression. Here, we show that (i) the hyperactivation of SOC channels is mediated by the STIM1 sensor and can be attenuated by STIM1 knockdown or 2-aminoethoxydiphenyl borate application, (ii) the STIM2 is not involved in pathological changes of SOC entry, (iii) the pathological SOC entry demonstrates properties of both TRPC and Orai subunit composition, and (iiii) transgenic Drosophila flies with PS1 ?E9 expression in the cholinergic neuron system show short-term memory loss, which can be abolished by 2-aminoethoxydiphenyl borate feeding.     

Saposin A mobilizes lipids from low cholesterol and high bis(monoacylglycerol)phosphate-containing membranes: patient variant Saposin A lacks lipid extraction capacity

Saposin A (Sap-A) is one of five known sphingolipid activator proteins required for the lysosomal degradation of sphingolipids and for the loading of lipid antigens onto antigen-presenting molecules of the CD1 type. Sap-A assists in the degradation of galactosylceramide by galactosylceramide-beta-galactosidase in vivo, which takes place at the surface of intraendosomal/intralysosomal vesicles. Sap-A is believed to mediate the interaction between the enzyme and its membrane-bound substrate. Its dysfunction causes a variant form of Krabbe disease. In the present study we prepared glycosylated Sap-A free of other Saps, taking advantage of the Pichia pastoris expression system. Using liposomes and surface plasmon resonance spectroscopy, we tested the binding and lipid mobilization capacity of Sap-A under different conditions. Along the endocytic pathway, the pH value decreases, and the lipid composition of intraendosomal and intralysosomal membranes changes drastically. In the inner membranes the cholesterol concentration decreases, and that of the anionic phospholipid bis(monoacylglycero)phosphate increases. Here, we show that Sap-A is able to bind to liposomes and to mobilize lipids out of them at acidic pH values below pH 4.7. Low cholesterol levels and increasing concentrations of bis(monoacylglycero)phosphate favor lipid extraction significantly. Galactosylceramide as a bilayer component is not essential for lipid mobilization by Sap-A, which requires intact disulfide bridges for activity. We also show for the first time that glycosylation of Sap-A is essential for its lipid extraction activity. Variant Sap-A proteins, which cause storage of galactosylceramide in humans (Krabbe disease, Spiegel, R., Bach, G., Sury, V., Mengistu, G., Meidan, B., Shalev, S., Shneor, Y., Mandel, H., and Zeigler, M. (2005) Mol. Genet. Metab. 84, 160-166) and in mutant mice (Matsuda, J., Vanier, M. T., Saito, Y., Tohyama, J., and Suzuki, K. (2001) Hum. Mol. Genet. 10, 1191-1199) are deficient in lipid extraction capacity.     

Reagents for the selective immobilization of oligonucleotides on solid supports

New reagents (CPGs and phosphoramidites) for automatic solid phase synthesis of modified oligonucleotides were designed. Three oligonucleotides carrying fluorescent label at the 5'-terminus and an anchor group at the 3'-terminus were prepared and their immobilization in orthogonal conditions on solid supports was studied.     

5-arylethynyl-2'-deoxyuridines: energy transfer and SNP-detection

Energy transfer between different fluorescent 5-alkynyl-2' -deoxyuridines in complementary and mismatched duplexes was studied.     

LH2 Complex from Sulfur Bacteria Allochromatium vinosum – Natural Singlet Oxygen Sensor

Biochemistry (Moscow) - It was established that in a heterogeneous model system, which consisted of two types of complexes: reaction center or core complex of photosystem 2 of higher plants and LH2...     

'Cyclic alopecia' in Msx2 mutants: defects in hair cycling and hair shaft differentiation

Msx2-deficient mice exhibit progressive hair loss, starting at P14 and followed by successive cycles of wavelike regrowth and loss. During the hair cycle, Msx2 deficiency shortens anagen phase, but prolongs catagen and telogen. Msx2-deficient hair shafts are structurally abnormal. Molecular analyses suggest a Bmp4/Bmp2/Msx2/Foxn1 acidic hair keratin pathway is involved. These structurally abnormal hairs are easily dislodged in catagen implying a precocious exogen. Deficiency in Msx2 helps to reveal the distinctive skin domains on the same mouse. Each domain cycles asynchronously - although hairs within each skin domain cycle in synchronized waves. Thus, the combinatorial defects in hair cycling and differentiation, together with concealed skin domains, account for the cyclic alopecia phenotype.     

Effect of ammonium concentration on protein and chlorophyll contents and the number of ribosomes in the cells of soybean mixotrophic callus

The effects of exogenous ammonium concentrations on the contents of protein and chlorophyll and also the number of ribosomes in the cells of the mixotrophic callus of soybean (Glycine max L.) were studied. The curves of protein and chlorophyll contents differed at ammonium concentrations exceeded 20 mM. An increase in the content of protein and chlorophyll was observed in the range of ammonium concentrations between 2 and 10 mM. At lower concentrations, their contents were equal to control values. In the absence of ammonium from the nutrient medium, the number of ribosomes in the cells was low. The presence of ammonium in medium (0.01–20.0 mM) induced a manifold increase in the number of ribosomes, which did not depend on the ammonium concentration. It is supposed that ammonium is a factor controlling the formation and functioning of the protein-synthesizing machinery; its indirect effect on the content of the green pigment in chloroplasts of the mixotrophic callus cells is also discussed.