First finding of tiemannite, HgSe, in human bladder stones: An electron microprobe study

Human bladder stones, surgically removed from a 4 years old boy, were studied by X-ray diffraction (XRD) and by electron microprobe analyses (EPMA). XRD data show that the bladder stones are mainly composed of struvite with minor apatite. Tiny particles, <10 μm in size, composed of mercury (Hg) and selenium (Se) were found using scanning electron microscopy (SEM) and quantitative analysis by wave-length dispersive system (WDS). On the basis of their composition, the particles consist of tiemannite, a rare mineral with the ideal formula HgSe. The young patient was not exposed to relevant mercury contamination and has no teeth fillings of amalgam. Although this observation is not conclusive, we suggest that Hg was introduced as methylmercury by food. The discovered tiemannite can be classified as endogenous mineral, i.e., directly precipitated from the same fluids that formed the host bladder stones. This assumption is supported by the fact that tiemannite and struvite can crystallize at the same temperature and pH values. As proposed for the formation of tiemannite previously reported in the liver of cetaceans, we suggest that the tiemannite in the human body represents a probable product of demethylation of Hg. In this contribution, we suggest that Hg and Se were initially collected by urine in the human body and finally precipitated to form tiemannite under appropriate chemical-physical conditions together with the formation of the host bladder stone. This observation suggests that the precipitation and accumulation of metals, including Hg and Se, in the human body can be considered a physiological response to eliminate part of these trace elements, thus enabling detoxification.

Microwave dielectric property based classification of renal calculi: Application of a kNN algorithm

The proper management of renal lithiasis presents a challenge, with the recurrence rate of the disease being as high as 46%. To prevent recurrence, the first step is the accurate categorization of the discarded renal calculi. Currently, the discarded renal calculi type is determined with the X-ray powder diffraction method which requires a cumbersome sample preparation. This work presents a new approach that can enable fast and accurate classification of discarded renal calculi with minimal sample preparation requirements. To do so, first, the measurements of the dielectric properties of naturally formed renal calculi are collected with the open-ended contact probe technique between 500 MHz and 6 GHz with 100 MHz intervals. Cole-Cole parameters are fitted to the measured dielectric properties with the generalized Newton-Raphson method. The renal calculi types are classified based on their Cole-Cole parameters as calcium oxalate, cystine, or struvite. The classification is performed using k-nearest neighbors (kNN) machine learning algorithm with the 10 nearest neighbors, where accuracy as high as 98.17% is achieved.

Mineralogy and chemistry of urinary stones: patients from North Jordan

Urinary stone diseases are increasing in the Middle East. The majority of urinary stone cases are found in the northern part of the country. Stone samples taken from patients living in the Irbid area were collected from Princess Basma Hospital. The present study concentrates on the mineralogical and chemical composition of the urinary stones and on the effective environmental factors that assist in developing the different types of urinary stones. Using X-ray diffraction techniques, the mineralogical composition of the urinary stones was found to be as follows: oxalate, cholesten, and uric acid, with cystine stones occuring more frequently than the others. Cholesten and calcium oxalate stones are the most dominant types of stones. Calcium oxalate is the most common type of oxalate stone. Calcium oxalate is represented in: whewellite, wheddellite, and calcium carbonate oxalate hydrate minerals, in addition to other minerals such as brushite, ammonium phosphate, vaterite, valleriite, and bobierrite from other types of stones. Bobierrite (phosphate group) is a new mineral reported in urinary stones, and this has not been determined in any previous study worldwide. Apatite (calcium phosphate) is deduced using scanning electron microscope (SEM) images. The SEM technique determined crystal forms and systems, shapes, morphological features, and the names of the minerals forming urine stones, while optical properties are studied by polarizing microscope. X-ray fluorescence technique determined the concentrations of major and some trace elements. It revealed that Ca is the main constituent of the urinary stones, especially those composed of calcium oxalate and calcium phosphate. The concentration of trace elements was Ba = 1.57, P = 3.61, Fe = 1.78, S = 2.08, Zr = 4.63, Mo = 3.92, Cu = 1.89, Co = 1.56, and F = 4.2% and was higher in the urinary stones of Jordanian patients than in foreigners in the country. Questionnaires completed by patients suggest that the most significant factors directly effecting the formation of stones are water, climate conditions, food rich in protein and rich in different chemicals. Moreover, some drugs and diseases might also help in developing other stones.

Renal stone analysis: is there any clinical value?

It has usually been assumed that the analysis of recovered renal stones should be routinely done. This concept has recently been challenged. Very little work has been done to correlate analytical results with clinical findings and the impact of this information on clinical management. This paper reviews current concepts of stone formation, how this information can be used to interpret stone analysis results and how stone analyses results can be used in clinical-decision-making.

Urinary calculi: microbiological and crystallographic studies

Although referred to as "urinary calculus disease", the formation of stone in the urinary tract is not caused by a single etiological agent. As such, diverse clinical investigations to diagnose the cause of stone formation must be carried out and the course of management after diagnosis must inevitably be different in each case. This review will cover all aspects of calculus formation, but will give particular attention to calculi caused by infection of the urinary tract with urease-producing bacteria. This is a recurrent, potentially life-threatening disease which has led clinicians to refer to the condition as "stone cancer". Because the etiology of infection stones is so different from stones caused by metabolic disorders, the two disease patterns should be considered separately, a fact often overlooked in epidemiological studies of stone formation. The importance of analysis of calculi as an aid to management is thus emphasized; identification of stone type will help to indicate appropriate therapy. A review of methods of analysis will be covered, particularly crystallographic analysis. Inhibition of bacterial urease as a means of management of infection stones will be discussed together with problems encountered and brighter hopes for the future.

Estimation by infrared spectrophotometer of the calcium oxalate dihydrate to calcium oxalate monohydrate ratio

According to the theoretical expression for calibration curve as a function of the optical absorption ratio of two peaks and with the analysis of the infrared spectra of the mixture samples of commercial calcium oxalate monohydrate and synthesized calcium oxalate dihydrate, the following quadratic equation was obtained; Y = 1.79 X2 - 30.90 X + 107.04 in which Y is the percentage of the purity of calcium oxalate dihydrate and X is the ratio of the relative optical absorption at 660 cm.-1 (the wave number at a characteristic absorption peak of calcium oxalate monohydrate) to that at 610 cm.-1 (that of calcium oxalate dihydrate) by regarding the line as a base-line that links the absorption valley at around 700 cm.-1 with that at 550 cm.-1 The linear correlation coefficient of the actual purity to the estimated purity obtained from this formula of calcium oxalate dihydrate is 0.995. When this formula is applied to the results derived from the infrared spectra of the mixture samples of commercial calcium oxalate monohydrate and calcium oxalate dihydrate obtained from urinary stones in duplicate in each percentage, the linear correlation coefficient is 0.991. This estimation method by infrared spectrophotometer of the calcium oxalate dihydrate to calcium oxalate monohydrate ratio gave a very close correlation between actual and estimated purity of calcium oxalate dihydrate and seems useful in the study of calcium oxalate urolithiasis.