The role of salt abuse on risk for hypercalciuria

Background: Elevated sodium excretion in urine resulting from excessive sodium intake can lead to hypercalciuria and contribute to the formation of urinary stones. The aim of this study was to evaluate salt intake in patients with urinary lithiasis and idiopathic hypercalciuria (IH).Methods: Between August 2007 and June 2008, 105 lithiasic patients were distributed into 2 groups: Group 1 (n = 55): patients with IH (urinary calcium excretion > 250 mg in women and 300 mg in men with normal serum calcium); Group 2 (n = 50): normocalciuric patients (NC). Inclusion criteria were: age over 18 years, normal renal function (creatinine clearance >= 60 ml/min), absent proteinuria and negative urinary culture. Pregnant women, patients with intestinal pathologies, chronic diarrhea or using corticoids were excluded. The protocol of metabolic investigation was based on non-consecutive collection of two 24-hour samples for dosages of: calcium, sodium, uric acid, citrate, oxalate, magnesium and urinary volume. Food intake was evaluated by the three-day dietary record quantitative method, and the Body Mass Index (BMI) was calculated and classified according to the World Health Organization (WHO). Sodium intake was evaluated based on 24-hour urinary sodium excretion.Results: The distribution in both groups as regards mean age (42.11 +/- 10.61 vs. 46.14 +/- 11.52), weight (77.14 +/- 16.03 vs. 75.99 +/- 15.80), height (1.64 +/- 0.10 vs. 1.64 +/- plusorminus 0.08) and BMI (28.78 +/- 5.81 vs. 28.07 +/- 5.27) was homogeneous. Urinary excretion of calcium (433.33 +/- 141.92 vs. 188.93 +/- 53.09), sodium (280.08 +/- 100.94 vs. 200.44.93 +/- 65.81), uric acid (880.63 +/- 281.50 vs. 646.74 +/- 182.76) and magnesium (88.78 +/- 37.53 vs. 64.34 +/- 31.84) was significantly higher in the IH group (p < 0.05). There was no statistical difference in calcium intake between the groups, and there was significantly higher salt intake in patients with IH than in NC.Conclusions: This study showed that salt intake was higher in patients with IH as compared to NC.

Urinary lithiasis and idiopathic hypercalciuria: the importance of dietary intake evaluation

PUSPOSE: To evaluate food intake of patients with urinary lithiasis and idiopathic hypercalciuria (IH). MATERIALS and METHODS: Between August 2007 and June 2008, 105 patients with lithiasis were distributed into 2 groups: Group 1 (n = 55) - patients with IH (urinary calcium excretion > 250 mg in women and 300 mg in men with normal serum calcium); Group 2 (n = 50) - normocalciuria (NC) patients . Inclusion criteria were: age over 18, normal renal function (creatinine clearance = 60 mL/min), absent proteinuria and negative urinary culture. Pregnant women, patients with some intestinal pathology, chronic diarrhea or using corticoids were excluded. The protocol of metabolic investigation was based on non-consecutive collection of two 24-hour samples for dosages of: calcium, sodium, uric acid, citrate, oxalate, magnesium and urinary volume. Food intake was evaluated through the quantitative method of Dietary Register of three days. RESULTS: Urinary excretion of calcium (433.33 ± 141.92 vs. 188.93 ± 53.09), sodium (280.08 ± 100.94 vs. 200.44.93 ± 65.81), uric acid (880.63 ± 281.50 vs. 646.74 ± 182.76) and magnesium (88.78 ± 37.53 vs. 64.34 ± 31.84) was significantly higher in the IH group in comparison to the NC group (p < 0.05). As regards the nutritional composition of food intake of IH and NC groups, there was no statistical significant difference in any nutrient evaluated. CONCLUSION: In our study, no difference was observed in the food intake of patients with urinary lithiasis and IH or NC.

Photo-Fenton degradation kinetics of low ciprofloxacin concentration using different iron sources and pH

The aim of the present study was to compare the degradation kinetics of low (1 mg L-1) and high (25 mg L-1) concentrations of ciprofloxacin (CIP) aiming to decrease the concentration of additives and evaluate the pH limitation by the use of low iron concentrations and organic ligands. A parameterized kinetic model was satisfactorily fitted to the experimental data in order to study the performance of photo-Fenton process with specific iron sources (iron citrate, iron oxalate, iron nitrate) under different pH medium (2.5, 4.5, 6.5). The process modeling allowed selecting those process conditions (iron source, additives concentrations and pH medium) which maximize the two performance parameters related to the global equilibrium conversion and kinetic rate of the process. For the high CIP concentration, degradation was very influenced by the iron source, resulting in much lower efficiency with iron nitrate. At pH 4.5, highest TOC removal (0.87) was achieved in the presence of iron citrate, while similar CIP conversions were obtained with oxalate and citrate (0.98 after 10 min). For the low CIP concentration, much higher conversion was observed in the presence of citrate or oxalate in relation to iron nitrate up to pH 4.5. This behavior denotes the importance of complexation also at low dosages. Appropriate additives load (320 μM H 2O2; 6 μM Fe) resulted in a CIP conversion of 0.96 after10 min reaction with citrate up to pH 4.5. © 2013 Elsevier B.V. All rights reserved.

Litíase urinária e hipercalciúria idiopática: importância da avaliação da ingestão alimentar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da influência da orientação nutricional e do tratamento medicamentoso na recorrência da litíase urinária

Pós-graduação em Bases Gerais da Cirurgia - FMB

Influence of clinical therapy and nutritional counseling on the recurrence of urolithiasis

PURPOSE: To evaluate the influence of combined clinical therapy and nutritional guidance on the recurrence of urolithiasis. METHODS: From our registry of patients with recurrent urolithiasis we selected 57 who had at least 5-years of follow-up. We collected 24h urine samples in order to analyze Ca, Na, uric acid, citrate, oxalate, and Mg concentrations and to assess urine volume. Patients filled out a clinical questionnaire before treatment, and abdominal radiographs and/or ultrasound were performed both before treatment and during the follow-up period. During follow-up, specific and individualized dietary advice was given based on the individual's metabolic disorders. Patients also received specific pharmacological treatment for their metabolic alterations. Outcome measures were metabolites in urine and the urolith recurrence rate. Pre- and post- intervention values were compared using tests as appropriate. RESULTS: Fifty six of the patients were male and the majority of patients were overweight. The mean BMI was 27 kg/m2. Urinary excretion of calcium, uric acid and sodium decreased significantly over the five year follow-up period. The number of uroliths that formed during the 5-year follow-up also decreased significantly compared to pre-treatment values. CONCLUSION: Individualized dietary advice combined with pharmacological treatment significantly reduces long-term urolithiasis recurrence.

Consumo de amido e proteína, excreção de oxalato e características da urina de gatos alimentados com ração seca

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

L'oxalate: un déchet organique peu soluble, avec conséquences [Oxalate: a poorly soluble organic waste with consequences].

Oxalate is a highly insoluble metabolic waste excreted by the kidneys. Disturbances of oxalate metabolism are encountered in enteric hyperoxaluria (secondary to malabsorption, gastric bypass or in case of insufficient Oxalobacter colonization), in hereditary hyperoxaluria and in intoxication (ethylene glycol, vitamin C). Hyperoxaluria causes a large spectrum of diseases, from isolated hyperoxaluria to kidney stones and nephrocalcinosis formation, eventually leading to kidney failure and systemic oxalosis with life-threatening deposits in vital organs. New causes of hyperoxaluria are arising recently, in particular after gastric bypass surgery, which requires regular and preemptive monitoring. The treatment of hyperoxaluria involves reduction in oxalate intake and increase in calcium intake. Optimal urine dilution and supplementation with inhibitors of kidney stone formation (citrate) are required. Some conditions may need vitamin B6 supplementation, and the addition of probiotics might be useful in the future. Primary care physicians should identify cases of recurrent calcium oxalate stones and severe hyperoxaluria. Further management of hyperoxaluria requires specialized care.

Extraction and concentration of biogenic calcium oxalate from plant leaves

The objective of this study was to extract and concentrate calcium oxalate (CaOx) crystals from plant leaves that form the above mentioned crystals. The chemical and physical studies of CaOx from plant to be performed depend on an adequate amount of the crystals. The plant used in this study was croton (Codiaeum variegatum). The leaves were ground in a heavy duty blender and sieved through a 0.20 mm sieve. The suspension obtained was suspended in distilled water. The crystals were concentrated at the bottom of a test tube. The supernatant must be washed until it is free of plant pigments and other organic substances. Biogenic CaOx crystals have well-defined and sharp peaks, indicating very high crystallinity. Moreover, the CaOx crystals were not damaged during the extraction procedure, as can be seen on the scanning electron microscope images. The porposed method can be considered efficient to extract and concentrate biogenic calcium oxalate.

Study of calcium oxalate monohydrate of kidney stones by X-ray diffraction

X-ray powder diffraction was used to study the phase composition of human renal calculi. The stones were collected from 56 donors in Vitoria, Espirito Santo state, southeastern Brazil. An XRD phase quantification revealed that 61% of the studied renal stones were composed exclusively of calcium oxalate [34% formed only by calcium oxalate rnonohydrate (COM) and 27% presents both monohydrate and dihydratate calcium oxalate]. The 39% multi-composed calculi have various other phases such as uric acid and calcium phosphate. Rietveld refinement of XRD data of one apparent monophasic (COM) renal calculus revealed the presence of a small amount of hydroxyapatite. The presence of this second phase and the morphology of the stone (ellipsoidal) indicated that this calculus can be classified as non-papillary type and its nucleation process developed in closed kidney cavities. In order to show some advantages of the X-ray powder diffraction technique, a study of the phase transformation of monohydrate calcium oxalate into calcium carbonate (CaCO(3)) was carried out by annealing of a monophasic COM calculi at 200, 300, and 400 degrees C for 48 h in a N(2) gas atmosphere. The results of the XRD for the heat treated samples is ill good agreement with the thermogravimetric analysis found in the literature and shows that X-ray powder diffraction can be used as a suitable technique to study the composition and phase diagram of renal calculi. (C) 2008 International Centre for Diffraction Data.

Effect of Oxalate Desensitizer on the Durability of Resin-Bonded Interfaces

Potassium oxalate desensitizers were previously shown to effectively reduce the immediate permeability of resin-bonded dentin. The current study evaluated whether the effect of the combined application of oxalate with etch-and-rinse adhesives interferes with the durability of resin-dentin bonds when using etch-and-rinse adhesives. The bond strength of resin-bonded dentin specimens composed of two-step or three-step etch-and-rinse adhesives (Single Bond, One-Step and Scotchbond Multi-Purpose, respectively) was tested immediately (24 hours) and after 12 months of water storage. The adhesives were used either according to the manufacturers` instructions (control groups) or after treating acid-etched dentin with a potassium oxalate gel (BisBlock, BISCO, Inc). The treatment of dentin with potassium oxalate was shown to negatively affect the baseline bond strength of resin-bonded dentin specimens, regardless of the adhesive used (p<0.05). After storage, the bond strength of the resin-bonded interfaces was significantly reduced for all the tested groups (p<0.001). Nevertheless, the rate of decreasing bond strength was significantly lower for oxalate-treated specimens than for the controls (p<0.05).

Functional characterization of the oxaloacetase encoding gene and elimination of oxalate formation in the beta-lactam producer Penicillium chrysogenum

Penicillium chrysogenum is widely used as an industrial antibiotic producer, in particular in the synthesis of g-lactam antibiotics such as penicillins and cephalosporins. In industrial processes, oxalic acid formation leads to reduced product yields. Moreover, precipitation of calcium oxalate complicates product recovery. We observed oxalate production in glucose-limited chemostat cultures of P. chrysogenum grown with or without addition of adipic acid, side-chain of the cephalosporin precursor adipoyl-6-aminopenicillinic acid (ad-6-APA). Oxalate accounted for up to 5% of the consumed carbon source. In filamentous fungi, oxaloacetate hydrolase (OAH; EC3.7.1.1) is generally responsible for oxalate production. The P. chrysogenum genome harbours four orthologs of the A. niger oahA gene. Chemostat-based transcriptome analyses revealed a significant correlation between extracellular oxalate titers and expression level of the genes Pc18g05100 and Pc22g24830. To assess their possible involvement in oxalate production, both genes were cloned in Saccharomyces cerevisiae, yeast that does not produce oxalate. Only the expression of Pc22g24830 led to production of oxalic acid in S. cerevisiae. Subsequent deletion of Pc22g28430 in P. chrysogenum led to complete elimination of oxalate production, whilst improving yields of the cephalosporin precursor ad-6-APA. (C) 2011 Elsevier Inc. All rights reserved.

Simultaneous Determination of Choline Citrate and Acetylmethionine in Injectable Solutions by High Performance Liquid Chromatography

Choline citrate (CC) and acetylmethionine (AM) are lipotropic drugs used in several pharmaceutical formulations. The objective of this research was to develop and validate a high performance liquid chromatographic (HPLC) method for simultaneous determination of CC and AM in injectable solutions, aiming its application in routine analysis for quality control of these pharmaceutical formulations. The method was validated using a Shim-Pack (R) C18 (250 x 4.6 mm, 5 mu m) column. The mobile phase was constituted of 25 mM potassium phosphate buffer solution, pH 5.7, adjusted with 10 % orthophosphoric acid, acetonitrile and methanol (88:10:2, v/v/v). The flow rate was 1.1 mL.min(-1) and the UV detection was made at 210 nm. The analyses were made at room temperature (25 +/- 1 degrees C). The method is precise, selective, accurate and robust, and was successfully applied for simultaneous quantitative determination of CC and AM in injectables.

Citrate and Phosphate Influence on Green Fluorescent Protein Thermal Stability

Protein structure and function can be regulated by no specific interactions, such as ionic interactions in the presence of salts. Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. The aim of this study was to evaluate the thermal stability of GFP in the presence of different salts at several concentrations and exposed to constant temperatures, in a range of 70-95 degrees C. Thermal stability was expressed in decimal reduction time. It was observed that the D-values obtained were higher in the presence of citrate and phosphate, when compared with that obtained in their absence, indicating that these salts stabilized the protein against thermal denaturation. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 27: 269-272, 2011

Liquid-liquid extraction of proteases from fermented broth by PEG/citrate aqueous two-phase system

This work deals with the use of an aqueous two-phase system (ATPS) of PEG/citrate to remove proteases from a Clostridium perfringens fermentation broth. To plan the experimental tests and evaluate the corresponding results, three successive experimental designs were employed, for which the PEG molar mass (M-PEG) and concentration (C-PEG), the citrate concentration (C-C) and the pH were selected as independent variables, while the purification factor (PF), the partition coefficient (K), the activity yield (Y) and the selectivity (S) were selected as responses. PF of proteases in the top phase was shown to increase with increasing MPEG and decreasing Cc, whereas a completely opposite trend was observed for K. On the other hand, Y was favored by simultaneous decreases in both these variables, while S decreased with increasing Cc. Therefore, selecting a simultaneous increase in PF and Y as the most desirable result, the best performance of the system was obtained using M-PEG = 10-000 g/mol C-PEG = 22% (w/w) and C-c = 8.0% (w/w) at pH 8.5. Under these conditions, the activity yield was very high (131 %) but the purification factor (4.2) and the selectivity (4.3) were lower than those ensured by more selective purification methods. According to these results, the ATPS seems to be an interesting alternative primary concentration/decontamination step for vaccine preparation from C. perfringens fermented broth. (C) 2007 Elsevier B.V. All rights reserved.