A label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) based on platinum (II)-oligonucleotide coordination induced gold nanoparticles aggregation.

Herein, a gold nanoparticles (AuNPs) based label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) was constructed for the first time. Four bases (G-G mismatch) mismatched streptavidin aptamer (MSAA) was used to protect AuNPs from salt-induced aggregation and recognize Pt (II) specifically. Only in the presence of Pt (II), coordination occurs between G-G bases and Pt (II), leading to the activation of streptavidin aptamer. Streptavidin coated magnetic beads (MBs) were used as separation agent to separate Pt (II)-coordinated MSAA. The residual less amount of MSAA could not efficiently protect AuNPs anymore and aggregation of AuNPs will produce a colorimetric product. With the addition of Pt (II), a pale purple-to-blue color variation could be observed by the naked eye. A detection limit of 150nM and a linear range from 0.6µM to 12.5µM for Pt (II) could be achieved without any amplification.

Changes in Some Divalent Cations Concentrations In An Experimental Rat Model of Gentamicin-Induced Acute Renal Failure.

Aim: The changes in divalent cations concentration were assessed in and experimentally gentamicin-induced renal failure in white Wistar rats. Material and Methods: The white male Wistar rats were distributed into 4 groups of 7 animals each and were treated intraperitoneally as follows: Group I (Control): distilled water in a volume of 0.5ml/100g rat/day for10 days; Group II (Ge): gentamicin 80 mg/kbw/day for 7 days; Group III (Ge+Zn): gentamicin 80 mg/kbw/day for 7 days and ZnCl2 5 mg/kbw/day for 10 days prior to administration of Ge and then another 7 days simultaneously with Ge administration; Group IV (Zn): ZnCl2 5 mg/kbw/day for 17 days. Before starting the experiment (I0) and at 3, 7 and 10 days after the first Ge administration, magnesium, copper and zinc plasma concentrations and urinary magnesium levels were determined. Results: Zn administration significantly decreased (p<0.001) plasma Mg concentrations in Ge+Zn group compared to Ge group after 7 days in the experiment, and induced a lower urinary elimination of Mg in Ge+Zn group (p<0.05) than in Ge group (p<0.01). Also, Zn induced a slight augmentation of Cu concentration in Ge+Zn group (p<0.05) compared to Ge group after 7 and 10 days. Conclusions: The variation in divalent cation concentrations in the context of renal diseases may be helpful for an early diagnosis and effective alternative therapeutic measures.

DNA-functionalized upconversion nanoparticles as biosensors for rapid, sensitive, and selective detection of Hg(2+) in complex matrices.

We have developed a facile one-step approach to make hydrophilic and DNA-functionalizable upconversion nanoparticles (UCNPs), which are used to act as a biosensor for determining Hg(2+) in complex matrices. The proposed approach is simple and exhibits low background interference, high sensitivity and rapid response.

Analysis of renal stones by capillary isotachophoresis.

An analytical method for the determination of the composition of renal stones by capillary isotachophoresis with conductometric detection was developed. Using different leading/terminating electrolyte systems, the qualitative and quantitative analysis of organic compounds (urate, xanthate, oxalate) and inorganic ions (phosphate, Ca(2+), Mg(2+), Na(+), NH(4)(+)) species commonly present in mixed renal stones in three separate steps can be carried out with limits of detection about 10 µmol/L. The developed method was validated by the analysis of real samples and can be used for urinary calculi classification. In addition, it was verified that this method can also be employed for the determination of the above mentioned analytes in some other samples (bones, teeth) concerning apatite biominerals (fluoro-, carbonate-, chloro-apatite).

Divalent cations levels change in nephrotic syndrome.

UNLABELLED: Divalent cations (calcium, magnesium, zinc, cooper, manganese) play an important role in various biological processes. Different acute or chronic renal disorders in children or adults modify the urinary excretion of these cations and may influence their concentrations in organism. AIM: Evaluation of the changes of some divalent cations levels (Cu, Zn, Mg, Ca) in acute renal diseases. MATERIAL AND METHODS: We measured plasma concentrations and urinary excretion of cations in pediatric patients with acute urinary infections. We also evaluated malondyaldehide (MDA) and total antioxidant capacity (TAC) plasma levels. RESULTS: The obtained results show that serum levels of Ca, Cu, Zn are decreased in patients with acute urinary infections compared with a control group of healthy children, while urinary excretion of Cu and Zn there were higher in group study compared with control group. There are no significant differences of the serum magnesium concentration. Increased plasma MDA levels and decreased plasma TAC, Cu and Zn concentrations indicate an increased oxidative stress in patients with acute renal diseases. CONCLUSIONS: Our preliminary data show that in some acute urinary conditions, such as lower urinary tract infection and pyelonephritis, appear disturbances of plasma and urinary concentrations of divalent cations. We consi der that trace elements should be measured routinely in children with renal disorders.

Influence of therapy with metformin on the concentration of certain divalent cations in patients with non-insulin-dependent diabetes mellitus.

Research was performed on a group of 30 patients with non-insulin-dependent diabetes mellitus (NIDDM), who never received antidiabetic medication before, and on a group of 17 healthy adults. The patients were administered treatment with metformin, 1,000 mg/day. Plasmatic and urinary concentration of magnesium have been measured, copper and zinc along with the concentrations of glucose, HDL, LDL, cholesterol, tryglicerides, HbA1c, and total erythrocyte magnesium, in advance and after 3 months of treatment. Data showed significant differences in the NIDDM group vs the control group: for plasma magnesium-1.95 ± 0.19 vs 2.20 ± 0.18 mg/dl, p < 0.001; urine magnesium-237.28 ± 34.51 vs 126.25 ± 38.22 mg/24 h, p < 0.001; erythrocyte magnesium-5.09 ± 0.63 vs 6.38 ± 0.75 mg/dl, p < 0.001; plasma zinc-67.56 ± 6.21 vs 98.41 ± 20.47 µg/dl, p < 0.001; urine zinc-1,347.54 ± 158.24 vs 851.65 ± 209.75 µg/24 h, p < 0.001; plasma copper-111.91 ± 20.98 vs 96.33 ± 8.56 µg/dl, p < 0.001; and urine copper-51.70 ± 23.79 vs 36.00 ± 11.70 µg/24 h, p < 0.05. Treatment with metformin for 3 months modified significant erythrocyte magnesium-5.75 ± 0.61 vs 5.09 ± 0.63 mg/dl, p < 0.001 and urine magnesium-198.27 ± 27.07 vs 237.28 ± 34.51 mg/24 h, p < 0.001, whereas it did not modify significant the plasmatic and urinary concentration of the other cations. The erythrocyte magnesium concentration was inversely correlated with HbA1c (r = -0.438, p = 0.015). The plasma level of copper was positively correlated with HbA1c (r = 0.517, p < 0.003), tryglicerides (r = 0.534, p < 0.003), and cholesterol (r = 0.440, p < 0.05), and the plasma level of zinc was inversely correlated with glycemia (r = -0.399, p = 0.029). Our data show a significant action of metformin therapy, by increasing the total intraerythrocyte magnesium concentration and decreasing the urinary magnesium elimination, positively correlated with the decrease of glycemia and HbA1c in NIDDM patients.

Synthesis and application of alizarin complexone functionalized polyurethane foam: preconcentration/separation of metal ions from tap water and human urine.

A new chelating sorbent has been synthesized by the covalent condensation of alizarin complexone (ALC) to polyurethane foam (PUF) through -N=C- group. The material was characterized by IR, (1)H NMR and chemical proof. Iminodiacetic acid groups are found in the prepared sorbent and the reaction proceeded via condensation between the toluidine moieties in the PUF and non-hydrogen bonded carbonyl group in ALC. Also, the possibility of elimination reaction between the groups (NH(2), NH and OH) in the polymer and carboxylic groups in the reagent was excluded. The material has been used to separate/preconcentrate Cu(2+), Zn(2+) and Cd(2+) prior to their determination by flame atomic absorption spectrometry (FAAS). Chemical and flow variables such as sample pH, sorbent capacity, sample flow rate and interference from co-existing ions were investigated. All metal ions are quantitatively desorbed by 0.1 mol L(-1) nitric acid solution. The procedure provides concentration factor 100 and limits of detection 0.013 microg mL(-1). The method was validated by the analysis of certified reference materials and real samples such as tap water and human urine.

Reevaluation of the criteria for the clinical diagnosis of Gitelman syndrome.

A 16-year-old female had mutations in both alleles of the gene encoding her sodium-chloride cotransporter; one of these mutations is newly described. Her clinical findings were not typical because of the absence of hypocalciuria in 24-h urine samples, her maximum urine osmolality (U(osm)) was only 802 mosmol/kg H(2)O, and her plasma magnesium (Mg) concentration (P(Mg)) was easily maintained in the normal range with oral Mg supplements for 1 month. In detailed studies, the calcium/creatinine ratio in spot urines with a U(osm) >700 mosmol/kg H(2)O was very low, except during Mg therapy. Renal medullary function did not appear to be compromised because she had a non-urea U(osm)of approximately 600 mosmol/kg H(2)O, reflecting a very high non-urea osmole excretion rate (due to KCl supplements). At age 18 years, her P(Mg) became persistently low despite Mg therapy. We conclude that the clinical criteria for a provisional diagnosis of Gitelman syndrome should be revised. Hypocalciuria may only be evident initially in concentrated spot urine samples. Urine concentrating ability should include an analysis of the non-urea U(osm), especially when patients are taking large KCl supplements.

Catheter associated urinary tract infection and encrustation.

This paper examines the relationship between urinary pH, infection and urinary catheter encrustation and discusses the current management and problems of catheter associated urinary infection and encrustation.

Serum and urinary divalent cations and plasma renin activity in women with mild pregnancy-induced hypertension.

Serum concentrations and urinary output of calcium, magnesium, sodium and potassium were analysed in normotensive pregnant women and in women with pregnancy-induced hypertension during the third trimester. In addition, plasma renin activity (PRA) was also determined. Significantly lower serum total calcium, urinary calcium and magnesium excretions and plasma renin activity were evident in women with PIH. Urine output and creatinine clearance were not significantly different between the two groups. No significant correlation was evident between serum calcium, magnesium and PRA. The relationship between these parameters and high blood pressure is not immediately apparent. They nevertheless suggest of a disturbance in electrolyte metabolism in women with PIH, that may underly the pathogenesis of this disorder.

The association between blood pressure, calcium and other divalent cations: a population study.

This report investigated the associations between blood pressure and the levels of various divalent cations in blood and urine in the population at large. The 1,982 participants (963 men and 1019 women; mean age 48 years) constituted a stratified random sample of the population of 4 Belgian districts. Systolic/diastolic pressure averaged 133/78 mmHg in men, and 128/76 mmHg in women. Serum total calcium (2.37 mmol/l), serum magnesium (1.00 mmol/l) and blood cadmium (10.0 nmol/l) were on average similar in the two sexes. By contrast, serum zinc (13.1 and 12.6 mumol/l, respectively), blood lead (0.56 and 0.36 mumol/l) and the urinary excretions of calcium (4.86 and 3.95 mmol/24h), copper (0.16 and 0.13 mumol/24h), and cadmium (9.4 and 7.2 nmol/24h) were significantly higher in men than in women. After adjustment for significant blood pressure covariates (age, body mass index, pulse rate, log gamma-glutamyltranspeptidase, smoking habits, and in women the contraceptive pill), serum total calcium was independently and positively correlated with systolic pressure in both sexes, and with diastolic pressure in women. After similar adjustments systolic pressure was positively correlated with urinary copper in men and women. In addition, systolic pressure and blood lead, and diastolic pressure and urinary cadmium were negatively correlated in men. In conclusion, this population study demonstrated a positive relationship between systolic blood pressure and both serum total calcium and urinary copper.

Renal excretion of divalent ions in response to chronic acidosis: evidence that systemic pH is not the controlling variable.

Although metabolic acidosis produces calciuric, phosphaturic, and magnesiuric effects, the consequences of chronic respiratory acidosis are unclear. To examine the role of systemic pH on renal divalent metabolism, 4-day balance studies were performed in rats with both metabolic acidosis induced by adding 1.5% NH4Cl to the drinking water, and respiratory acidosis produced by exposure to 10% atmospheric CO2 in an environmental chamber, and in controls pair-fed with each group. By the fourth day, blood pH had decreased to an identical degree with both chronic metabolic and respiratory acidosis and averaged 7.28. As anticipated, chronic metabolic acidosis resulted in significant calciuria, magnesiuria, and phosphaturia. However, despite the similar decrement in blood pH, calcium, phosphorus, and magnesium excretion was similar to that in the pair-fed controls with chronic respiratory acidosis. These findings indicate that a low systemic pH, per se, does not account for the modifications in urinary divalent ion handling that accompany chronic metabolic acidosis. However, additional observations suggest that differences in the intracellular pH of the proximal tubular epithelium may be an important regulatory variable.

Structural and functional adaptation after reduction of nephron population.

This review of adaptive changes in renal structure and function in subjects with reduced renal mass has two primary goals. One is to provide a description of the remarkable compensatory increases in glomerular filtration rate (GFR), and renal blood flow, at the level of individual nephrons, and the alterations in water and electrolyte transport by tubular epithelium. These processes preserve fluid and electrolyte balance in subjects with progressive renal failure, until whole kidney GFR is reduced to about 20 percent of normal, and provide the basis for conservative clinical medical management. The other aim is an attempt to provide an understanding of the mechanisms involved in compensatory adaptation, since this information, in addition to amplifying our understanding of renal transport processes, helps to elucidate the functional limitations placed on subjects with renal insufficiency. An attempt has been made to analyze both clinical observations and relevant experimental models and an effort has been made to correlate renal function with different patterns of renal injury.