ABSTRACT
PURPOSE: To compare chemical to morphological kidney stone composition analysis based on a sample of 50 stones retrieved from patients at a nephrology service. METHODS: The chemical analysis was performed with a Bioclin® kit, while a 10-mm magnifying glass (10x; Prolabo, Paris, France) was employed in the morphological analysis. Findings obtained with the two methods were compared and classified as concordant (100 percent agreement), partly concordant (concordant for major components, discordant for minor components) or discordant (discordant for major components). RESULTS: In the chemical analysis, the most commonly observed major component was calcium (70 percent), followed by oxalate (66 percent), ammonium (56 percent), urate (28 percent) and carbonate (24 percent). In the morphological analysis, the most commonly observed major components were calcium phosphate and magnesium (32 percent each), followed by calcium oxalate monohydrate (24 percent), uric acid and urates (20 percent each), calcium oxalate dihydrate (18 percent) and cystine (6 percent). Infectious kidney stones were identified in 34 percent and 24 percent of cases by morphological and chemical analysis, respectively. Thirty-eight percent of the samples were classified as concordant, 52 percent were partly concordant and 10 percent were discordant. CONCLUSION: We suggest kidney stones be routinely submitted to both types of analysis for a better understanding of the mechanisms involved in lithogenesis.(AU)
OBJETIVO: Comparar a análise química com a análise morfológica de 50 cálculos urinários provenientes de pacientes em um serviço de nefrologia. MÉTODOS: A análise química foi realizada utilizando o kit da Bioclin®, enquanto que a morfológica foi realizada com auxílio de uma lupa de 10mm (Prolabo, Paris, France). A comparação entre as técnicas foi classificada em concordante (100 por cento de concordância), parcialmente concordante (componentes majoritários concordantes e minoritários discordantes) e discordante (discordância nos componentes majoritários). RESULTADOS: Na análise química os principais componentes majoritários foram cálcio (70 por cento), oxalato (66 por cento), amônio (56 por cento), urato (28 por cento) e carbonato (24 por cento). Na análise morfológica os principais componentes majoritários foram fosfato cálcico (PCa) e magnesiano-PCa (32 por cento), oxalato de cálcio monohidratado (24 por cento), ácido úrico e uratos (20 por cento), oxalato de cálcio dihidratado (18 por cento) e cistina (6 por cento). Cálculos de infecção foram identificados em 34 por cento e 24 por cento casos pela análise morfológica e química, respectivamente. Concordância total foi observada em 38 por cento, concordância parcial em 52 por cento e discordância em 10 por cento. CONCLUSÃO: Sugere-se a utilização simultânea das duas técnicas para melhor compreensão dos mecanismos litogênicos.(AU)
Subject(s)
Urinary Bladder Calculi/diagnosis , Urinary Bladder Calculi/ultrastructure , Kidney Calculi/diagnosis , Kidney Calculi/ultrastructure , Urinary Calculi/diagnosis , Urinary Calculi/ultrastructure , Double-Blind MethodABSTRACT
One of the defenses against nephrolithiasis is provided by macromolecules that modulate the nucleation, growth, aggregation and retention of crystals in the kidneys. The aim of the present study was to determine the behavior of two of these proteins, Tamm-Horsfall and uromodulin, in calcium oxalate crystallization in vitro. We studied a group of 10 male stone formers who had formed at least one kidney stone composed of calcium oxalate. They were classified as having idiopathic nephrolithiasis and had no well-known metabolic risk factors involved in kidney stone pathogenesis. Ten normal men were used as controls, as was a group consisting of five normal women and another consisting of five pregnant women. Crystallization was induced by a fixed supersaturation of calcium oxalate and measured with a Coulter Counter. All findings were confirmed by light and scanning electron microscopy. The number of particulate material deposited from patients with Tamm-Horsfall protein was higher than that of the controls (P<0.001). However, Tamm-Horsfall protein decreased the particle diameter of the stone formers when analyzed by the mode of the volume distribution curve (P<0.002) (5.64 +/- 0.55 microm compared to 11.41 +/- 0.48 microm of uromodulin; 15.94 +/- 3.93 microm and 12.45 +/- 0.97 microm of normal men Tamm-Horsfall protein and uromodulin, respectively; 8.17 +/- 1.57 microm and 9.82 +/- 0.95 microm of normal women Tamm-Horsfall protein and uromodulin, respectively; 12.17 +/- 1.41 m and 12.99 +/- 0.51 microm of pregnant Tamm-Horsfall protein and uromodulin, respectively). Uromodulin produced fewer particles than Tamm-Horsfall protein in all groups. Nonetheless, the total volume of the crystals produced by uromodulin was higher than that produced by Tamm-Horsfall protein. Our results indicate a different effect of Tamm-Horsfall protein and uromodulin. This dual behavior suggests different functions. Tamm-Horsfall protein may act on nucleation and inhibit crystal aggregation, while uromodulin may promote aggregation of calcium oxalate crystals.