Solid state NMR of salivary calculi: Proline-rich salivary proteins, citrate, polysaccharides, lipids, and organic–mineral interactions

Solid state NMR (ssNMR) can characterize mineral (31P) and organic (13C) components of human salivary stones (n = 8). All show apatitic 31P spectra. 13C ssNMR indicates more protein, of more consistent composition, than apatitic uroliths, with signals from Tyr, Phe and His prominent. Citrate and lipid, identified by dipolar dephasing (DD), and polysaccharides are also observable in varying amounts. 13C{31P} rotational echo double resonance (13C{31P} REDOR) identifies carbon atoms in close (< ca. 0.5 nm) proximity to phosphorus and therefore probably binding with mineral. Citrate, sugar and carboxylate signals undergo strong 13C{31P} REDOR, also seen to signals between 50 and 60 ppm, from protein α- carbons and, possibly, phosphoserines and phospholipids, and sometimes to a 35 – 40 ppm envelope containing Asp-Cβ and Glu-Cγ signals. Amino acid analysis indicates high proline and aromatic content. 13C ssNMR and amino acid composition is consistent with preponderance of proline-rich salivary proteins such as statherin.The U.K. EPSRC (Y. L.) and MRC (D. G. R.) for fundingThis is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.crci.2015.07.00

Urinary Calculi: Review of Classification Methods and Correlations with Etiology

Current physical and chemical methods available for urinary stones analysis are critically reviewed. No one method is sufficient to provide all the clinically useful information on the structure and composition of the stones. We show that a combination of refined morphological and structural examination of stone with optical microscopy, complemented by compositional analysis using infrared spectroscopy of the core, cross-section and surface of calculi, provides a precise and reliable method for identifying the structure and crystalline composition, and permits quantification of stone components while being highly cost effective. Using such morphoconstitutional studies leads to a classification of urinary stones in seven distinctive types and twenty-one subtypes among monohydrate (whewellite) and dihydrate (weddellite) calcium oxalates, phosphates, uric acid, urates, protein, and cystine calculi. Furthermore, all of the recognized sub-types exhibit correlations with specific pathophysiologic conditions. We conclude that such morphoconstitutional refined analysis and classification of urinary calculi is of interest to properly identify the type of stone disease and provides clues to etiopathogeny

Renal colic in a dialysis patient: a case of renal stone disease

Renal colic in a dialysis patient: a case of renal stone diseas

A Physiological Approach to Recurrent Nephrolithiasis and its Genetic Determinants

We report a case of a 63-year-old patient with recurrent nephrolithiasis for over 40 years and a significant family history of nephrolithiasis. The patient underwent full investigation at our department. He presented hypercalcemia, hypophosphatemia and hypercalciuria, with parathyroid hormone level in the normal range. A calcium load test and a fluorocholine PET-CT excluded primary hyperparathyroidism. Abnormal secretion of parathyroid hormone-related protein and sarcoidosis were also excluded. Genetic analysis showed mutations encoding for 25(OH)-vitamin D3-24-hydroxylase (CYP24A1) and Na-dependent phosphate cotransporter 2c (SLC34A3). This case affords insights into the biological pathways that underlie the role of genetic inheritance and accrued risk of development of nephrolithiasis.info:eu-repo/semantics/publishedVersio

Possible deviations from Griffith's criterion in shallow slabs, and consequences on slab avalanche release

International audiencePossible reasons for deviations from Griffith's criterion in slab avalanche triggerings are examined. In the case of a major basal crack, we show (i) that the usual form of Griffith's criterion is valid if elastic energy is stored in a shallow and hard slab only, and (ii) that rapid healing of broken ice bonds may lead to shear toughnesses larger than expected from tensile toughness experiments. In the case of avalanches resulting from failure of multi-cracked weak layers, where a simple Griffith's criterion cannot be applied, frequency/size plots obtained from discrete elements and cellular automata simulations are shown to obey scale invariant power law distributions. These findings are confirmed by both frequency/acoustic emission duration and frequency/size plots obtained from field data, suggesting that avalanche triggerings may be described using the formalism of critical phenomena

Methodological Aspects of Spontaneous Crystalluria Studies in Calcium Stone Formers

Despite nearly a half-century of study, the clinical value of spontaneous crystalluria (Cx) examinations in calcium stone formers (CaSF) is still uncertain. The analytical complexity of urine particle study is largely responsible for this situation. As a result, there is no consensus regarding technical methods in Cx with several techniques for urine sampling and three different instruments currently used for particle study, namely, particle counting (PC), light microscopy (LM) and petrographic microscopy (PM). In this work, we first examined urine sampling and instrument methods regarding their appropriateness for Cx studies. Then we performed a comparative analysis of Cx studies in CaSF. Despite many technical and clinical discrepancies, several studies agree that the frequency of all particles and of the weddellite and whewellite calcium oxalate (CaOx) crystalline phases are increased in CaSF as compared to normal subjects (NS). Particle sizes and aggregation ratio are also often increased. Altogether, these results reinforce the need for an efficient method for Cx studies in these patients. Examining each technique leads us to conclude that most particle parameters can be studied by direct LM observation of freshly voided urine samples, i.e., urine samples without any separation steps. For clinical applications, several examinations should be performed, first to define the specific Cx characteristics in a patient, then for the study of treatment efficiency on Cx control, and finally, during the patient follow-up. Due to Cx variability in each patient, the frequency of Cx examinations during each phase needs to be determined in long-term comparative prospective studies of CaSF

Calcium Tartrate Tetrahydrate, Case Report of a Novel Human Kidney Stone

Background: Calcium tartrate tetrahydrate has been reported as the main mineral in urinary stones in rats that have significant tartrate in their diet, but in humans, there has been only one mention of calcium tartrate stones in the form of bladder stone, and that case was in Africa., Case Presentation: Patient is a 34-year-old Caucasian male who presented with typical symptoms of nephrolithiasis. CT abd/pelvis (renal stone protocol) revealed a 2 cm nonobstructing stone of the right renal pelvis. Patient underwent an uncomplicated right percutaneous nephrolithotomy and was noted to be stone free after surgery. Stone analysis was difficult with regard to determining composition, but was finally identified as calcium tartrate tetrahydrate., Conclusion: This was an unusual case, as this is the first recorded case of a calcium tartrate tetrahydrate outside of Africa. This type of stone had only been mainly described in rat models with dl-bitartrate in their diet. Our patient was an otherwise healthy, relatively muscular individual with no obvious source for this stone other than a vitamin and amino acid supplement that he takes regularly that contains l-carnitine (as tartrate) and choline (as bitartrate and citrate). The prevalence of this stone type is presently unknown, as stone analysis laboratories have not had the ability to recognize it. Although a connection between the supplement and stone formation is conjecture at this time, we believe this necessitates further investigation

Morphologies of three-dimensional shear bands in granular media

We present numerical results on spontaneous symmetry breaking strain localization in axisymmetric triaxial shear tests of granular materials. We simulated shear band formation using three-dimensional Distinct Element Method with spherical particles. We demonstrate that the local shear intensity, the angular velocity of the grains, the coordination number, and the local void ratio are correlated and any of them can be used to identify shear bands, however the latter two are less sensitive. The calculated shear band morphologies are in good agreement with those found experimentally. We show that boundary conditions play an important role. We discuss the formation mechanism of shear bands in the light of our observations and compare the results with experiments. At large strains, with enforced symmetry, we found strain hardening.Comment: 6 pages 5 figures, low resolution figures

Shedding Light on the Chemical Diversity of Ectopic Calcifications in Kidney Tissues: Diagnostic and Research Aspects

In most industrialized countries, different epidemiologic studies show that chronic renal failure is dramatically increasing. Such major public health problem is a consequence of acquired systemic diseases such as type II diabetes, which is now the first cause for end stage renal failure. Furthermore, lithogenic diseases may also induce intratubular crystallization, which may finally result in end-stage renal failure (ESRF). Up to now, such rare diseases are often misdiagnosed. In this study, based on twenty four biopsies, we show that SR µFTIR (Synchrotron Radiation-µFourier transform infrared) spectroscopy constitutes a significant opportunity to characterize such pathological µcalcifications giving not only their chemical composition but also their spatial distribution in the tissues. This experimental approach offers new opportunities to the clinicians to describe at the cell level the physico-chemical processes leading to the formation of the pathological calcifications which lead to ESRF

7,9-Bis(hy­droxy­meth­yl)-7H-purine-2,6,8(1H,3H,9H)trione

The structure of the title uric acid derivative, C7H8N4O5, from human kidney stones, is characterized by the C and O atoms of one of the two hy­droxy­methyl groups being disordered nearly equally over three different sites. In the crystal, mol­ecules are connected by a three-dimensional hydrogen-bonding scheme though they look stacked in planes nearly parallel to (04)