Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.101
Filtrar
1.
Phys Chem Chem Phys ; 22(8): 4788-4792, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32068201

RESUMO

Precipitation and dissolution of calcium oxalate monohydrate (CaOx) crystals are relevant due to their major role in kidney stone diseases. To such an extent, small molecules and ions can act as inhibitors to prevent the formation of calcium oxalate monohydrate crystals. Herein, we explored the role of citrate and the counter cation Na+ ions in the dissolution of CaOx crystals. Citrate binds on the Ca2+ sites of the CaOx crystals to form calcium citrate. Dissolution of CaOx increases with the increase in the concentration of citrate ions and time of incubation. We observed that corrugations were formed on the surface of the CaOx crystals after the sodium citrate treatment during the dissolution process. Theoretical studies revealed that Na+ occupies the vacant site of Ca2+ in CaOx making a strain on the surface which leads to the subsequent deformation of the crystal.


Assuntos
Oxalato de Cálcio/química , Citratos/química , Sódio/química , Cristalização
4.
Life Sci ; 241: 117108, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31786192

RESUMO

AIMS: Telmisartan (TLM), a highly selective angiotensin II type 1 receptor blocker (ARB) and partial PPAR-γ agonist, has versatile beneficial effects against oxidative stress, apoptosis, inflammatory responses and epithelial-mesenchymal transition (EMT). However, its underlying mechanism of inhibiting oxalate and calcium oxalate (CaOx) crystal-induced EMT by activating the PPAR-γ pathway remains unclear. MAIN METHODS: CCK-8 assays were used to evaluate the effects of TLM on cell viability. In addition, intracellular reactive oxygen species (ROS) levels were measured by the cell-permeable fluorogenic probe 2,7-dichlorofluorescein diacetate (DCFH-DA). Wound-healing and Transwell assays were used to evaluate the migration ability of HK2 cells exposed to oxalate. Moreover, immunofluorescence, immunohistochemistry and western blotting were used to examine the expression of E-cadherin, N-cadherin, vimentin and α-SMA and explore the underlying molecular mechanisms in HK2 cells and a stone-forming rat model. KEY FINDINGS: Our results showed that TLM treatment could protect HK2 cells from oxalate-induced cytotoxicity and oxidative stress injury. Additionally, TLM prevented EMT induction by oxalate and CaOx crystals via the PPAR-γ-AKT/STAT3/p38 MAPK-Snail pathway in vitro and in vivo. However, knockdown of PPAR-γ with small interfering RNA or the PPAR-γ-specific antagonist GW9662 abrogated these protective effects of TLM. SIGNIFICANCE: As a PPAR-γ agonist, TLM can ameliorate oxalate and CaOx crystal-induced EMT by exerting an antioxidant effect through the PPAR-γ-AKT/STAT3/p38 MAPK-Snail signaling pathway. Therefore, TLM can block EMT progression and could be a potential therapeutic agent for preventing and treating calcium oxalate urolithiasis formation and recurrence.


Assuntos
Transição Epitelial-Mesenquimal/efeitos dos fármacos , Oxalatos/toxicidade , PPAR gama/metabolismo , Telmisartan/farmacologia , Animais , Oxalato de Cálcio/toxicidade , Linhagem Celular , Transição Epitelial-Mesenquimal/fisiologia , Humanos , Túbulos Renais/citologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , PPAR gama/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley , Fator de Transcrição STAT3/metabolismo , Fatores de Transcrição da Família Snail/metabolismo , Fator de Crescimento Transformador beta1/toxicidade , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
5.
Int Braz J Urol ; 46(1): 70-80, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31851461

RESUMO

OBJECTIVE: To analyze the compositions of upper urinary tract stones and investigate their distributions in different gender and age groups. MATERIALS AND METHODS: Patients diagnosed with upper urinary tract stone disease between December 2014 and March 2018 were retrospectively reviewed. Patient's age, gender, BMI, comorbidities, stone event characteristics, and compositions were collected, and proportions of stone components in different gender and age groups were analyzed. RESULTS: A total of 1532 stone analyses were performed (992 from males and 540 from females). The mean age was younger in males (p<0.001). Males included more cases with larger BMI, hyperuricemia, and obesity, while females had more urinary tract infections. Multiple components were present in 61.8% of stones. Calcium oxalate (CaOx) (67.0%) was the most common component, followed by uric acid (UA) (11.8%), infection stone (11.4%), calcium phosphate (CaP) (8.0%), cystine (1.1%), brushite (0.4%), and 2,8-dihydroxyadenine (0.2%). Men contributed with more CaOx stones than women at age 30-49 years (all p<0.01) and more UA stones at 30-59 years (all p<0.05). Women contributed with more infection stones than men in age groups 30-49 and 60-69 years (all p<0.05), and more CaP stones at 30-49 years. The prevalence peak was 50-59 years in men and 60-69 years in women. Both genders had the lowest prevalence in adolescence. Prevalence of UA stones increased while that of infection stones decreased with aging in both genders. CONCLUSIONS: Age and sex had a strong association with distribution of stone compositions in this Chinese cohort.


Assuntos
Cálculos Urinários/química , Cálculos Urinários/epidemiologia , Adenina/análogos & derivados , Adenina/análise , Adulto , Distribuição por Idade , Fatores Etários , Oxalato de Cálcio/análise , Fosfatos de Cálcio/análise , China/epidemiologia , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Fatores de Risco , Distribuição por Sexo , Fatores Sexuais , Ácido Úrico/análise , Cálculos Urinários/etiologia
6.
Urology ; 137: e6-e7, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31887350

RESUMO

Jackstone calculus is a rare bladder stone with a unique appearance, presenting a stippled and spiculated contour. Correct diagnosis is important because it may have therapeutic implications, as this distinctive shape correlates with a specific mineral composition of calcium oxalate dihydrate, which tend to be easily fragmented by lithotripsy, allowing to attempt an endoscopic treatment instead of surgery in larger stones. We present the case of a 77-year-old male where a 2 cm bladder calculus was incidentally found on CT, with features that allowed to make straightforward the diagnosis of a jackstone calculus.


Assuntos
Cálculos da Bexiga Urinária/patologia , Idoso , Oxalato de Cálcio/análise , Humanos , Achados Incidentais , Masculino , Tomografia Computadorizada por Raios X , Cálculos da Bexiga Urinária/química , Cálculos da Bexiga Urinária/diagnóstico por imagem
7.
Environ Sci Technol ; 53(23): 13794-13801, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31682103

RESUMO

Low-molecular-weight organic acids such as oxalate, which are ubiquitous in the environment, can control the solubility and bioavailability of toxic metals such as Pb in soils and water by influencing complexation and precipitation reactions. Here, we investigated Pb solubility in relation to Pb-oxalate precipitation at pH 5.0 in the absence and presence of calcium (Ca), a common cation in environmental matrices. At Pb mole fractions less than 0.10, sequestration of Pb into Ca oxalate to form a solid solution substantially lowered Pb solubility relative to that of pure Pb oxalate to an extent inversely proportional to the Pb mole fraction. Small Pb/Ca solid-solution distribution coefficients at these low mole ratios was largely attributed to the stronger complexation of Pb compared to Ca with oxalate to form soluble metal-oxalate complexes, which in turn limited Pb incorporation into the Ca-oxalate crystal lattice. Characterization of the Pb/Ca-oxalate coprecipitates by X-ray diffraction, optical microscopy, and Fourier transform infrared spectroscopy revealed that the whewellite (Ca-oxalate monohydrate) structure was destabilized by substitution of small amounts of Pb into the lattice, and thus, the formation of the Ca-oxalate dihydrate (weddellite) was favored over the monohydrate. At Pb mole fractions above 0.20, discrete crystallites of Pb oxalate were identified. These new findings imply that Pb/Ca-oxalate coprecipitates in the presence of Ca could reduce the solubility of Pb in Pb-contaminated acid soils.


Assuntos
Oxalato de Cálcio , Minerais , Compostos Orgânicos , Oxalatos , Solubilidade , Difração de Raios X
8.
Urologe A ; 58(11): 1281-1288, 2019 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-31501986

RESUMO

Knowledge of the risk factors for urolithiasis is the key for sufficient metaphylaxis and reduction of recurrence events. Modifiable risk factors include diet, drink quantity, occupation, environmental factors, number of pregnancies and the intestinal microbiome. The treatment of associated diseases, such as the various manifestations of metabolic syndrome can reduce the risk for urolithiasis and recurrences. Knowledge of non-modifiable risk factors, such as gender, ethnicity, positive family history as well as specific genetic defects and polymorphisms of the calcium and phosphate balance enables personalized counselling and follow-up of affected patients.


Assuntos
Urolitíase , Oxalato de Cálcio , Humanos , Síndrome Metabólica , Recidiva , Fatores de Risco
9.
J Vet Intern Med ; 33(5): 2090-2095, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31471926

RESUMO

BACKGROUND: Positive health implications of early recognition of calcium oxalate (CaOx) urolithiasis include increased opportunity for nonsurgical removal, early dietary modification to minimize urolith growth, early removal to avoid urinary obstruction, and early recognition of genetic and metabolic diseases before they contribute to additional morbidity. OBJECTIVES: To identify high- and low-risk dog breeds for CaOx uroliths and to determine the relationship of age and sex to the development of CaOx uroliths. ANIMALS: Calcium oxalate urolith submissions between 2010 and 2015. METHODS: A comparative cross-sectional study was conducted to identify high- and low-risk breeds for CaOx uroliths by comparing cases to multiple comparison groups. At-risk breeds were identified if odds ratios were significant (P value <.05) across all comparison groups. RESULTS: Of 258 898 urolith submissions, 124 285 were CaOx. Calcium oxalate was identified in 212 breeds. Twelve breeds were identified as high-risk breeds, and 14 breeds were identified as low-risk breeds. All high-risk breeds were small dog breeds, and all low-risk breeds were medium to large dog breeds. Overall, the mean age ± standard deviation of the first CaOx urolith was 8.4 ± 2.8 years. CONCLUSIONS AND CLINICAL IMPORTANCE: To achieve the health benefits of preclinical evaluation, breeds at high risk for CaOx urolithiasis should be screened at 5 to 6 years of age, which is 2 to 3 years before likely development of clinical urolithiasis.


Assuntos
Doenças do Cão/epidemiologia , Nefrolitíase/veterinária , Cálculos Urinários/veterinária , Fatores Etários , Animais , Oxalato de Cálcio/análise , Estudos Transversais , Doenças do Cão/genética , Cães , Feminino , Predisposição Genética para Doença , Masculino , Nefrolitíase/epidemiologia , Nefrolitíase/genética , Fatores de Risco , Fatores Sexuais , Estados Unidos , Cálculos Urinários/química , Cálculos Urinários/epidemiologia
10.
Kidney Blood Press Res ; 44(4): 777-791, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31408871

RESUMO

BACKGROUND: M2 macrophages have important roles in diseases such as tumours, cardiovascular diseases and renal diseases. This study aimed to determine the effects and protective mechanism of M2 macrophages against oxidative stress injury and apoptosis induced by calcium oxalate crystals (CaOx) in renal tubular epithelial cells (HK-2) under coculture conditions. METHODS: THP-1 cells were induced to differentiate into M2 macrophages by using phorbol-12-myristate-13-acetate, IL-4 and IL-13. Morphological features were observed by microscopy. Phenotypic markers were identified by reverse transcription-polymerase chain reaction, Western blot and enzyme-linked immunosorbent assay (ELISA). HK-2 cells were treated with 0.5 mg/mL CaOx crystals and co-cultured with M2 macrophages or apocynin. The viability of HK-2 cells was detected by CCK-8 assay. The lactate dehydrogenase (LDH) activity of HK-2 cells was analysed using a microplate reader. The apoptosis of HK-2 cells was examined by flow cytometry and Hoechst 33258 staining. Reactive oxygen species (ROS) expression and mitochondrial membrane potential in HK-2 cells were detected by a fluorescence microplate reader. Western blot analysis was conducted to detect the expression of p47phox, Bcl-2, cleaved caspase-3, cytochrome c, p38 MAPK, phospho-p38 MAPK, Akt and phospho-Akt. RESULTS: The results of morphology, reverse transcription-polymerase chain reaction, Western blot and ELISA showed that THP-1 cells were successfully polarised to M2 macrophages. The results of co-culture suggested that M2 macrophages or apocynin significantly increased the cell viability and decreased the LDH activity and apoptosis rate after HK-2 cells were challenged with CaOx crystals. The expression of the p47phox protein and the concentration of ROS were reduced, the release of mitochondrial membrane potential and the expression of the Bcl-2 protein were upregulated and the protein expression of cleaved caspase-3 and cytochrome c was downregulated. The expression of the phosphorylated form of p38 MAPK increased. Under coculture conditions with M2 macrophages, the Akt protein of HK-2 cells treated with CaOx crystals was dephosphorylated, but the phosphorylated form of Akt was not reduced by apocynin. CONCLUSIONS: M2 macrophages reduced the oxidative stress injury and apoptosis of HK-2 cells by downregulating the activation of NADPH oxidase, reducing the production of ROS, inhibiting the phosphorylation of p38 MAPK and enhancing the phosphorylation of Akt. We have revealed one of the possible mechanisms by which M2 macrophages reduce the formation of kidney stones.


Assuntos
Apoptose/efeitos dos fármacos , Oxalato de Cálcio/farmacologia , Túbulos Renais/efeitos dos fármacos , Macrófagos/fisiologia , Estresse Oxidativo , Acetofenonas/farmacologia , Antioxidantes/farmacologia , Linhagem Celular , Técnicas de Cocultura , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Humanos , Cálculos Renais , Túbulos Renais/lesões , Túbulos Renais/patologia , Fosforilação , Espécies Reativas de Oxigênio/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
11.
Urologe A ; 58(11): 1272-1280, 2019 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-31432240

RESUMO

The process of kidney stone formation is complex and still not completely understood. Supersaturation and crystallization are the main drivers for the etiopathogenesis of uric acid, xanthine and cystine stones but this physicochemical concept fails to adequately explain the formation of calcium-based nephrolithiasis, which represents the majority of kidney stones. Contemporary concepts of the pathogenesis of calcium-based nephrolithiasis focus on a nidus-associated stone formation of calcium-based nephrolithiasis on Randall's plaques or on plugs of Bellini's duct. Randall's plaques originate from the interaction of interstitial calcium supersaturation in the renal papilla, vascular and interstitial inflammatory processes and mineral deposits of calcifying nanoparticles on the basal membrane of the thin ascending branch of the loop of Henle; however, plugs of Bellini's duct are assumed to be caused by mineral deposits on the wall of the collecting ducts. Aggregation and overgrowth are influenced by the interaction of matrix proteins with calcium supersaturated urine, by an imbalance between promoters and inhibitors of stone formation in the calyceal urine. Current research has elucidated many factors contributing to stone formation by revealing novel insights into the physiology of nephron and papilla, by analyzing vascular, inflammatory and calcifying processes in the renal medulla, by examining the proteome, the microbiome, promoters and inhibitors of stone formation in the urine and by conducting the first genome-wide association studies; however, more future research is mandatory to fill the gap of knowledge and hopefully, to obtain novel prophylactic, therapeutic and metaphylactic tools beyond the current state of knowledge.


Assuntos
Nanopartículas Calcificantes , Cálculos Renais , Nefrolitíase , Cálculos Urinários , Oxalato de Cálcio , Humanos , Medula Renal/fisiopatologia
17.
Artigo em Inglês | MEDLINE | ID: mdl-31255901

RESUMO

Urolithiasis is a common urological disease with a high morbidity and recurrence rate, of which calcium oxalate (CaOx) is the most common type of stone that underlies the disease. However, the potential metabolic mechanisms of CaOx urolithiasis remain unclear. The present study aimed to seek potential biomarkers and metabolic mechanisms of CaOx urolithiasis in adults. Urine samples were collected from 36 healthy individuals and 36 patients diagnosed with bilateral upper-urinary-tract stones. All of the stones were composed of CaOx. Ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was used to perform a metabolic fingerprinting analysis. Principal component analysis (PCA) and orthogonal partial least-squares determinant analysis (OPLS-DA) were carried out to analyze the multivariate data. There were 18 differential metabolites identified, which mainly involved caffeine, phenylalanine, galactose, and tyrosine metabolism. The results revealed potential urinary biomarkers, via metabolic fingerprinting of adults with CaOx urolithiasis, which may help to improve future metabolic evaluation of urolithiasis. The elucidated metabolic pathways may have potential applications as novel treatment targets of CaOx urolithiasis. Additionally, our study suggests that the UPLC-Q-TOF/MS platform may offer new insights into the pathobiology of urolithiasis.


Assuntos
Biomarcadores/urina , Oxalato de Cálcio/urina , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas/métodos , Nefrolitíase/diagnóstico , Adulto , Feminino , Humanos , Masculino , Metabolômica , Pessoa de Meia-Idade , Nefrolitíase/urina , Adulto Jovem
18.
Int J Nanomedicine ; 14: 4277-4292, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31239679

RESUMO

Background: Kidney stone formation is closely related to renal epithelial cell damage and the adhesion of calcium oxalate crystals to cells. Methods: In this research, the adhesion of human kidney proximal tubular epithelial cells (HK-2) to calcium oxalate monohydrate crystals with a size of approximately 100 nm was studied. In addition, the inhibition of crystal adhesion by four tea polysaccharides (TPS0, TPS1, TPS2, and TPS3) with the molecular weights of 10.88, 8.16, 4.82, and 2.31 kDa, respectively were compared. Results: When oxalic acid-damaged HK-2 cells were repaired, cell viability increased. By contrast, reactive oxygen species level, phosphatidylserine eversion, and osteopontin expression decreased, thus indicating that tea polysaccharides have a repairing effect on damaged HK-2 cells. Moreover, after repairing the damaged cells, the amount of adherent crystals was reduced. The repair effect of tea polysaccharides is closely related to molecular weight, and TPS2 with the moderate molecular weight displayed the best repair effect. Conclusion: These results suggest that tea polysaccharides, especially TPS2, may inhibit the formation and recurrence of calcium oxalate kidney stones.


Assuntos
Oxalato de Cálcio/farmacologia , Polissacarídeos/farmacologia , Chá/química , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Cristalização , Fluorescência , Humanos , Nanopartículas/química , Osteopontina/metabolismo , Espécies Reativas de Oxigênio/metabolismo
19.
Urologiia ; (1): 28-34, 2019 Apr.
Artigo em Russo | MEDLINE | ID: mdl-31184014

RESUMO

INTRODUCTION: In recent years, a large number of studies has been published that proved a very significant role of diabetes mellitus type 2 for development of urolithiasis. The aim of our work was to conduct a comparative study of biochemical parameters of blood and urine as well as chemical composition of urinary stones in urolithiasis patients in the general population and in patients with diabetes mellitus type 2. MATERIALS AND METHODS: The work was divided into 2 stages. During the first stage an analysis of chemical composition of urinary stones in the general population (n=5669) and in patients with diabetes mellitus type 2 was carried out (n=350). During the second stage an analysis of biochemical parameters of blood and urine in urolithiasis patients in the general population (n=101) and in patients with diabetes mellitus type 2 was conducted (n=350). RESULTS: In the general population calcium oxalate stones was predominated (56.8%), while phosphate (24.9%) and urate (17.4%) stones were less frequent. In a subgroup of patients with diabetes mellitus type 2 uric acid stones were predominated (74.3%), significantly exceeding calcium oxalate (15.1%) and calcium phosphate (10.6%) stones. In the general population of patients with urolithiasis, hypercalciuria, hyperuricosuria, hyperuricemia and hypomagnesiuria was detected in 60.4%, 42.6%, 26.7% and 43.5% of cases, respectively. In patients with concomitant diabetes mellitus type 2, hypercalciuria, hyperuricosuria, hyperuricemia was observed in 9.4%, 26.7% and 42.5%, respectively. In 60.3% of patients with diabetes mellitus type 2 marked acidity of the morning urine was detected (pH<6.0). CONCLUSION: Correction of metabolic disorders in patients with urinary stone disease and diabetes mellitus type 2 should be aimed at increasing of urine pH and reducing the level of uric acid in the blood and urine.


Assuntos
Diabetes Mellitus Tipo 2 , Cálculos Urinários , Urolitíase , Oxalato de Cálcio , Diabetes Mellitus Tipo 2/complicações , Humanos , Ácido Úrico , Urolitíase/complicações , Urolitíase/patologia
20.
Urologiia ; (1): 105-112, 2019 Apr.
Artigo em Russo | MEDLINE | ID: mdl-31184027

RESUMO

All theories of stone formation are based on the common condition, which is the supersaturation of stone-forming elements. The microelements involved in the stone formation, the most common metabolic disorders and their role in stone formation are discussed.


Assuntos
Doenças Metabólicas , Cálculos Urinários , Urolitíase , Oxalato de Cálcio , Humanos , Incidência , Fatores de Risco , Cálculos Urinários/epidemiologia , Urolitíase/epidemiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA