Neural Network Analysis of Crystalluria Content to Predict Urinary Stone Type.

PURPOSE: To investigate the relationship between urinary stone type and the type of crystals in the urine. PATIENTS AND METHODS: This retrospective study involved 485 patients with urinary stones treated at King Saud University Medical City from May 2015 to June 2017. Clinical data were obtained from medical records. Different statistical analysis methods were applied, including basic contingency analysis, analysis of variance, logistic regression, discriminant analysis, partition modeling, and neural network evaluations. RESULTS: Of 485 patients, 47 had crystals detected by urinalysis. The most common type of crystal was calcium oxalate (n = 31), which had the highest association with calcium oxalate stones. Uric acid crystals (n = 8) were associated with uric acid stones. The neural network model used for determining the sensitivity and specificity showed an R-square value of 0.88, with an area under the curve of 0.94 for calcium oxalate, 0.94 for carbonate apatite, and 1.0 for uric acid. CONCLUSION: The predictive algorithm developed in the present study may be used with a patient's clinical parameters to predict the stone type. This approach predicts the stone types associated with certain patient characteristics with a high sensitivity and specificity, indicating that the models may be a valuable clinical tool in the diagnosis, management, and monitoring of stone diseases.

Urinary crystal formation and urothelial effects of pyroxasulfone administered to male rats.

Pyroxasulfone induced a low incidence of urinary bladder tumors in male rats in a 2-year bioassay at 1000 and 2000 ppm, with occasional urinary calculi. No increased incidence of tumors of any tissue occurred in female rats or in mice of either gender. We performed three short-term studies to evaluate early development of pyroxasulfone-induced urinary crystals and urothelial cytotoxicity with consequent regenerative proliferation. First, male rats were treated with dietary 50, 1000 or 2000 ppm pyroxasulfone for 1, 3 or 7 days. The urothelium was examined by light and scanning electron microscopy (LM, SEM) and bromodeoxyuridine labeling index (BrdU LI). In two other studies, male rats were treated with dietary 20 000 ppm pyroxasulfone for 1 week. Urine collected at various times of day was examined by SEM and energy dispersive spectroscopy (EDS) or by LM, SEM, EDS, and infrared spectroscopy (IFS). Urinary crystals were present at various time points. EDS and IFS showed some contained calcium; others contained organic matter. Cytotoxicity was detected by SEM as cellular swelling, craters, and necrosis and by LM as cellular hypertrophy. Increased cell proliferation was detected by LM (hyperplasia), SEM (piling up of round cells), and by increased BrdU LI. There was no evidence of increased apoptosis. These findings support a mode of action for pyroxasulfone-associated bladder tumors in male rats involving formation of urinary crystals leading to urothelial cytotoxicity and regenerative proliferation. This is a high dose phenomenon, therefore, pyroxasulfone is not likely to be carcinogenic to humans at exposure levels that do not cause crystals with subsequent calculi formation in the urinary tract.

A virtuous diagnostic and therapeutic roadmap triggered by a motivated and skilful urinary sediment examination.

In this paper we describe how an accurate urinary sediment examination, which revealed the presence of a severe 2,8-dihydroxyadenine crystalluria, opened the way to an articulate and successful diagnostic and therapeutic roadmap for a rare and potentially severe renal disease.

Very unusual "needle- and pencil-like" uric acid crystals in the urine unmasked by infrared spectroscopy investigation.

In this paper we describe a case with very unusual "needle- and pencil-like" crystals, partly similar to those reported by other investigators, who considered them as due to uric acid. Quite importantly, infrared spectroscopy investigation which, to our knowledge, we have been the first to perform on this type of crystals, confirmed their nature as uric acid structures. This case demonstrates that the planet of urinary crystals still has several unknown facets and still deserves exploration.

"Daisy-like" crystals: A rare and unknown type of urinary crystal.

BACKGROUND: Crystals are well known structures of urinary sediment, most of which are identified by the combined knowledge of crystal morphology, birefringence features at polarized light, and urine pH. In this paper, we report on a cohort of subjects whose urine contained a very rare type of crystal, which we first described in 2004 and which, based on its peculiar morphology, we define as "daisy-like crystal" (DLcr). METHODS: Reports on DLcr were spontaneously sent to our laboratory over a 10.5-year period by different laboratory professionals and by one veterinary clinician who, in their everyday work, had come across DLcr. After the examination of DLcr images submitted, a number of other information were requested and partly obtained. RESULTS: DLcr were found in 9 human beings in 7 different laboratories, located in 4 countries (Italy, Belgium, Croatia, France). DLcr were found mostly in female (8/9), at all ages (3.5 to 93years), mostly in alkaline urine (pH6.0 to 7.5), at variable specific gravity values (1.010 to 1.030), either as isolated particles (2/8) or in association with other crystals (5/8) and/or leucocytes or bacteria (3/8). In addition, DLcr were found in the urine of a 1-year-old dog, examined in a veterinary clinic of Czech Republic. In 3 cases, DLcr were identified by manual microscopy, while in 7 cases by automated urine sediment analyzers. CONCLUSIONS: This paper confirms the possible presence in the urine of DLcr. However, further cases are needed to clarify their frequency, clinical meaning, and composition.

Litíase urinária e sua relação com os achados de cristalúria e hematúria na urinálise / Urolithiasis and its relation to the urinalysis findings of crystalluria and hematuria

Introdução: Litíase urinária é a formação de cálculos no trato urinário a partir de componentes presentes na urina. É uma doença crônica associada a um alto número de recorrência e hospitalizações. O objetivo do estudo foi verificar a frequência de cristalúria e a relação entre litíase urinária e os achados de cristalúria e hematúria em pacientes da região noroeste do estado do Rio Grande do Sul. Métodos: Estudo transversal no qual foram incluídos pacientes no período de março a dezembro de 2015. Exames qualitativos de urina e prontuários médicos foram revisados buscando-se dados de cristalúria e hematúria e diagnóstico da litíase. Resultados: Foram analisadas 688 amostras de urina, e 54 (7,85%) apresentaram cristalúria. Dos casos de cristalúria, cinco (9,3%) pacientes apresentaram litíase. Foi verificada significância estatística (p = 0,010) entre as variáveis de litíase e hemácias, mas não foi evidenciada significância estatística entre as variáveis de litíase e cristalúria (AU)

Introduction: Urolithiasis is the formation of stones in the urinary tract from urine components. It is a chronic disease associated high recurrence and hospitalization rates. The aim of this study was to determine the frequency of crystalluria and the relation between urolithiasis and crystalluria and hematuria findings in patients of northwestern Rio Grande do Sul. Methods: A cross-sectional study that enrolled patients from March to December of 2015. Urinalyses and medical records were reviewed searching for crystalluria and hematuria data, and diagnosis of lithiasis. Results: 688 urine samples were analyzed, and crystalluria was found in 54 (7.85%) of them. Considering the crystalluria cases, 5 (9.3%) of the patients also had lithiasis. Statistical significance was found (p = 0.010) between the variables of lithiasis and red blood cells, but no statistical significance was found between the variables of lithiasis and crystalluria. Conclusion: Crystalluria was not associated with lithiasis, while hematuria was associated with such disease (AU)