Type 2 diabetes and uric acid stones: A powder neutron diffraction investigation

International audienceBackground: Recent epidemiologic investigations have identified an association between type 2 diabetes and uric acid kidney stones. This association was more apparent in women than in men. However, male patients are more prone than women to form uric acid stones in upper and lower urinary tract. In addition, uric acid stone morphology may be different according to stone location. Finally, it was shown that uric acid stone prevalence is increasing with the patient’s age. Aim of the study: To compare uric acid crystal size as determined by powder neutron diffraction with clinical data and the gender of patients. Material and methods: Uric acid stones from 43 patients (24 males, 19 females) identified by Fourier transform infrared spectroscopy were investigated using Environmental Scanning Electron Microscopy and Powder neutron diffraction.Results: Uric acid anhydrous was the main crystalline form of the stones. The mean size of the crystals was 91.3 ± 28.5 nm. No significant differences were found regarding uric acid crystal size in the stones by comparison to the stone location or the patient’s age. However, particle sizes of uric acid kidney stones were significantly different between male and female patients (84.7 ± 5.3 vs. 140.2 ± 6.7 nm, p < 0.000003) in the absence of diabetes mellitus. Interestingly, when type 2 diabetes appeared, this structural difference between male and female vanished (76.1 ± 3.9 vs. 78.8 ± 4.2 nm, not significant). Thus, the complete set of structural data is in line with observations regarding epidemiological data. Some explanations based on supersaturation are discussed

From urolithiasis to pathological calcifications: A journey at the interface between physics, chemistry, and medicine. A tribute to Michel Daudon

International audienceMichel Daudon is a worldwide recognized biologist who performed several major breakthroughs in the field of urolithiasis. It is indeed difficult to address his outstanding personality and his great contributions to urolithiasis. Michel Daudon studied many aspects of urolithiasis, from urine crystals to kidney stone morphoconstitutional analysis. He is the author of more than 500 scientific articles on urolithiasis, and more generally on pathological calcifications, including several books and nice articles in the New England Journal of Medicine, The Lancet, Kidney International, among many others. Michel Daudon is not only a prolific writer; his broad fields of interests range from chemistry to biology or renal pathology, but also clinical bedside subjects explain his success and his attractive way of explaining pathophysiological processes. He has already given more than 300 lectures, in France as abroad

Chronic urine acidification by fludrocortisone to treat infectious kidney stones

Chronic urinary tract infections by urease-producing bacteria may increase urine pH and promote thereby the formation of recurrent kidney stones made of highly carbonated calcium phosphate apatite and struvite, a magnesium ammonium phosphate. To date, there is no safe and effective treatment decreasing urine pH on a long term. We hypothesized that fludrocortisone, a mineralocorticoid, would decrease urine pH by increasing proton secretion in the kidney collecting tubule. We report three cases of patients with kidney stone suffering from chronic urinary infection by urease-producing germs, treated by fludrocortisone on a long term. Urine pH decreased sustainably over several months and tolerance was good

Chronic urine acidification by fludrocortisone to treat infectious kidney stones

Chronic urinary tract infections by urease-producing bacteria may increase urine pH and promote thereby the formation of recurrent kidney stones made of highly carbonated calcium phosphate apatite and struvite, a magnesium ammonium phosphate. To date, there is no safe and effective treatment decreasing urine pH on a long term. We hypothesized that fludrocortisone, a mineralocorticoid, would decrease urine pH by increasing proton secretion in the kidney collecting tubule. We report three cases of patients with kidney stone suffering from chronic urinary infection by urease-producing germs, treated by fludrocortisone on a long term. Urine pH decreased sustainably over several months and tolerance was good

Foreword to microcrystalline pathologies: combining clinical activity and fundamental research at the nanoscale

This contribution underlines the key role of physicochemical characterisation techniques in the area of medical research. The starting point centres on the Mid-InfraRed platform located at the Tenon hospital and dedicated to multidisciplinary functional investigations. In the last two decades, we have enhanced this platform by creating a network combining researchers from varied disciplines such as physicists, chemists, and clinicians. The resultant research dynamism is underscored by metrics such as 71 references in Pubmed and 129 in Web of Science, and the high impact of the journals in which we have published (New England Journal of Medicine, Kidney International, Chemical Review...). It is of paramount importance to disseminate these physicochemical techniques among young doctors, and to establish collaborations with appropriate private companies

Foreword to microcrystalline pathologies: combining clinical activity and fundamental research at the nanoscale

This contribution underlines the key role of physicochemical characterisation techniques in the area of medical research. The starting point centres on the Mid-InfraRed platform located at the Tenon hospital and dedicated to multidisciplinary functional investigations. In the last two decades, we have enhanced this platform by creating a network combining researchers from varied disciplines such as physicists, chemists, and clinicians. The resultant research dynamism is underscored by metrics such as 71 references in Pubmed and 129 in Web of Science, and the high impact of the journals in which we have published (New England Journal of Medicine, Kidney International, Chemical Review...). It is of paramount importance to disseminate these physicochemical techniques among young doctors, and to establish collaborations with appropriate private companies

Crystal size in μ\mu crystalline pathologies and its clinical implication

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“Trust my morphology”, the key message from a kidney stone

International audienceThe Consensus Conference Group recently published an article in Urolithiasis highlighting the importance of urine and stone analysis in the metabolic evaluation of kidney stone formers (KSF) [1]. Indeed, each kidney stone contains the imprints of the conditions which created them during their 'lifetime in the kidney'. The morpho-constitutional classification method (MCC) established by Prof Michel Daudon correlates the morphological characteristics of stones with specific metabolic disorders [2]. Briefly, it distinguishes 7 types and 21 subtypes according to the crystalline composition and shape, color and structure of stones identified using an optical stereomicroscope (Table 1). This very specific method is easy to learn and provides the opportunity to quickly identify highly recurrent diseases, sometimes serious in their clinical consequences. Indeed, subtypes Ic, Ie, IIId, IVa2 and

XANES spectroscopy for the clinician

XANES spectroscopy, which uses synchrotron radiation as a probe, offers substantial information about the local structure of biological samples, encompassing those without long range order such as Pt anticancer molecules, and nanometre scale or amorphous particles of calcium phosphate. Its subcellular spatial resolution, as well as its capacity to operate at room temperatures and pressures represent major advantages for medical research. Moreover, paraffin embedded biopsy samples can be analysed without any further preparation, Key publications which illustrate these capacities are presented

XANES spectroscopy for the clinician

XANES spectroscopy, which uses synchrotron radiation as a probe, offers substantial information about the local structure of biological samples, encompassing those without long range order such as Pt anticancer molecules, and nanometre scale or amorphous particles of calcium phosphate. Its subcellular spatial resolution, as well as its capacity to operate at room temperatures and pressures represent major advantages for medical research. Moreover, paraffin embedded biopsy samples can be analysed without any further preparation, Key publications which illustrate these capacities are presented