Nephrolithiasis Associated with Nephrocalcinosis Is Primarily Composed of Carbonate Apatite.

INTRODUCTION: This study was designed to determine the mineral composition of calculi in nephrocalcinosis with nephrolithiasis, diagnose the underlying disease, and monitor the course of renal function in patients with nephrocalcinosis-nephrolithiasis. METHODS: Renal calculi extruded in a series of 8 patients with nephrocalcinosis were analysed using Fourier transmission infrared spectrometry. In 4 patients, next-generation sequencing using a nephrocalcinosis-nephrolithiasis panel was performed to determine the nature of the underlying disease. In addition, longitudinal analysis of renal function was performed in all patients. RESULTS: Seven patients revealed carbonate apatite as the sole constituent of renal calculi. One patient showed a mixed composition of dicalcium phosphate dihydrate/carbonate apatite at first analysis yet in subsequent episodes also had calculi composed of pure carbonate apatite. Further molecular analysis displayed distal renal tubular acidosis in 2 of 4 patients who consented to sequencing. No known genetic defect could be found in the other two cases. In line with prior reports, decline of renal function was dependent on underlying disease. Distal renal tubular acidosis revealed a progressive course of renal failure, whereas other causes showed stable renal function in long term analysis. CONCLUSION: Nephrocalcinosis with nephrolithiasis is a rare condition with heterogeneous aetiology. Yet mineral composition of renal calculi predominantly consisted of pure carbonate apatite. This uniform finding is similar to subcutaneous calcifications of various origins and might propose a general principle of tissue calcification. Progressive decline of renal function was found in distal renal tubular acidosis, whereas other conditions remained stable over time.

Common Histological Features Suggesting Enchondral Ossification Pathways in Calciphylaxis of Various Origins: A Study of Human Subcutaneous Tissue Biopsies.

Calciphylaxis is a rare, yet underdiagnosed condition causing high mortality in patients with severe renal and cardiovascular disease. Since knowledge of the pathophysiology of calciphylaxis is limited, a differential analysis of histological alterations in patient subgroups with various comorbidities might expose different disease phenotypes and allow deeper insights into the pathophysiology of the condition. Histological markers of osteogenesis and calcification were investigated in a group of 18 patients with clinically and histologically verified calciphylaxis, using immunohistochemical staining. Analysis of staining intensity and distribution of marker proteins in histological structures was performed to evaluate distinct patterns between subgroups with different clinical comorbidities in comparison with a control group. In all cases, immunohistochemical staining for bone matrix proteins, bone-morphogenic proteins and matrix-Gla proteins co-localized with subcutaneous vascular and interstitial calcifications. Significant expression of bone-morphogenic protein-7 and active matrix-Gla protein was observed. Mortality was associated with renal comorbidities and increased expression of bone-morphogenic protein-7. However, no distinct histological patterns were found between subgroups with renal disease, warfarin intake or coexisting micro- and macro-angiopathies. The upregulation of osteogenic markers (including bone-morphogenic protein-7) plays a major role in the development of calciphylaxis. Clinical outcome correlates with kidney function and phosphate handling, suggesting different pathophysiological mechanisms. However, biopsy  at late-stage disease shows a common histological phenotype, involving enchondral ossification.

Life-threatening vitamin D intoxication due to intake of ultra-high doses in multiple sclerosis: A note of caution.

Knowledge about complications of chronic ultra-high dose vitamin D supplementation is limited. We report a patient with primary progressive multiple sclerosis (MS) who presented with generalized weakness caused by hypercalcemia after uncontrolled intake of more than 50,000 IU of cholecalciferol per day over several months. Various treatment strategies were required to achieve normocalcemia. However, renal function improved only partly and further progression of MS was observed. We conclude that patients need to be informed about the risks of uncontrolled vitamin D intake and neurologists need to be alert of biochemical alterations and symptoms of vitamin D toxicity.

Mineral Depositions of Calcifying Skin Disorders are Predominantly Composed of Carbonate Apatite.

Subcutaneous calcifications can lead to complications, including pain, inflammation, ulceration and immobilization. Studies on the pathophysiology of mineral compositions and effective treatment modalities are limited. We therefore studied 14 patients with subcutaneous calcifications. Mineral material was collected and analysed by Fourier transform infrared spectrometry. Blood analyses were run to evaluate systemic alterations of mineral metabolism. Carbonate apatite (CAP) was found to be the single constituent in the majority of patients (n = 9, 64.3%), 3 cases (21.4%) had a composition of CAP and calcium oxalate dihydrate and one case had a combination of CAP and magnesium ammonium phosphate, whereas CAP was the major component in all 4 cases. Only one case showed predominantly calcium oxalate. Thus, CAP was found to be the only or predominant component in most cases of subcutaneous calcifications. Chemical analyses of the mineral compositions may aid in the development of new treatment regimes to improve the solubility of mineral components and to decrease extraosseous calcifications.

Clinical implications of fetuin-A.

Fetuin-A, also termed alpha2-Heremans-Schmid glycoprotein, is a 46kDa hepatocyte derived protein (hepatokine) and serves multifaceted functions.

The influence of two variants in the adenosine triphosphate-binding cassette transporter 1 gene on plasma lipids and carotid atherosclerosis.

Variants in the adenosine triphosphate-binding-cassette transporter 1 (ABCA1) gene are known to affect high-density lipoprotein cholesterol and plasma triglycerides and the development of atherosclerosis. We investigated the influence of the R219K and I883M variants in the ABCA1 gene on plasma lipids and carotid intima media thickness and plaque extent in 688 healthy men (40-60 years old). The R219K variant showed no effect on plasma lipids, but carriers of the K allele displayed a lower intima media thickness (P = .001) and a reduced risk of advanced plaque extent (odds ratio [OR], 0.59; 0.39-0.88; P = .009) compared with noncarriers. However, this risk reduction was observed in nonsmokers only (OR, 0.47; 0.27-0.80; P < .001), but not in smokers (OR, 0.75; 0.41-1.39; P = .2). The I883M variant showed no effect on plasma lipids or carotid atherosclerosis. Risk of advanced plaque extent was reduced in subjects carrying the R219K variant alone (OR, 0.59; 0.38-0.94; P = .025), but not in subjects carrying both variants. Haplotype distribution did not differ between subjects with and without advanced atherosclerosis irrespective of smoking history. We conclude that smoking abrogates the protective effect of the R219K.

Comparison of real-time PCR signal-amplified in situ hybridization and conventional PCR for detection and quantification of human papillomavirus in archival cervical cancer tissue.

Archival paraffin-embedded tumor specimens offer a wealth of information for both cancer research and for routine clinical applications. However, the use of formalin-fixed, paraffin-embedded specimens for quantitative real-time PCR is not yet a standard diagnostic method in many laboratories, in particular for the quantification of human papillomavirus (HPV). Particularly high-risk HPV types are involved in almost 100% of the carcinogenesis of cervical cancer. We compared the diagnostic applicability and sensitivity of real-time PCR to that of chromogenic tyramide-signal-amplified in situ hybridization and conventional PCR for the detection of HPV from archival tissue in 164 cases of carcinoma in situ and cervical cancer. Furthermore, we examined whether the viral load of HPV is of prognostic relevance. Our findings indicate that patients in tumor stage I with a lower viral load of HPV type 16 (HPV16; up to 1,000 copies/ng of DNA) had a significantly better survival than HPV 16-negative patients (P = 0.037). We observed a greater sensitivity of both real-time PCR and conventional PCR for the detection of HPV16 and -18 compared to signal amplified in situ hybridization. We found a considerable concordance between HPV16 (kappa = 0.661) and HPV18 (kappa = 0.781) status as measured by real-time PCR and conventional PCR, indicating similar sensitivities. We recognized an inhibitory effect of formalin fixation and paraffin embedding on the evaluation of real-time PCR quantification.