Electrocrystallization of calcium carbonate on carbon-based electrodes

Calcium carbonate was deposited by electrochemical reduction of oxygen to hydroxyl ions at various carbon-based electrodes. Although some vaterite was observed during earlier stages of the electrodeposition, the predominant polymorph during later stages was calcite. The average crystal size reached a value of 15 μm after 10 h at a glassy carbon electrode but the crystal growth rate was substantially accelerated when oxygen was catalytically reduced. The same average size of the calcite crystals in this case (Pt/C electrode) was reached within a period of 1.5 h. Efficient removal of CaCO₃ from water was demonstrated when using a porous aerogel carbon electrode and a potential sufficiently negative to promote reduction of water molecules within the pores.     

Studies on subcutaneous fat necrosis of the newborn

Summary Biopsy specimens from the skin and subcutaneous fat tissue of four cases with neonatal subcutaneous fat necrosis were made and investigated by light and electron microscopy at 2, 4, and 6 weeks, and 5 months (Case 2) from the onset of the disease. Three stages of ultrastructural change of fat cells were observed. The evolution of crystal formation in the fat cells was seen and phagocytosis of crystals and fat droplets by macrophages and foreign-body giant cells was also noted. In the light microscope accumulation of calcium concretions in the spaces between and inside the fat cells was found. In the electron microscope we detected foci of highly electrondense granules, which were similar in distribution and structure to calcium salts stained with the von Kossa method. Changes in small and medium size blood vessels were observed.This work was written during a stay supported by Max-Planck-Gesellschaft from Dec. 1. 1973 to March 31. 1975 in the Max-Planck-Institut für Klinische und Physiologische Forschung (W.G. Kerckhoff-Institut), Bad Nauheim, West Germany (Director: Prof. Dr. Wolfgang Schaper)     

丹红注射液减轻草酸钙结晶肾损伤的实验研究

目的：探讨丹红注射液对小鼠体内草酸钙结晶性肾损伤的影响。方法：36只C57BL／6小鼠随机分为6组,空白对照组（A组）、正常对照组（B组,生理盐水100mg／kg）、单纯结晶组（c组,乙醛酸盐100mg／kg）、丹红干预低剂量组（D组,100mg／kg）、中剂量组（E组,200mg／kg）、高剂量组（F组,300mg／kg）,丹红干预组为乙醛酸盐诱导结晶肾损伤基础上加用不同浓度的丹红注射液,在连续给药7d后,检测各组小鼠血生化指标,肾组织钙含量水平,比较各组小鼠超氧化物歧化酶（SOD）、谷胱甘肽还原酶（GSH）、过氧化氢酶（CAT）和丙二醛（MDA）含量或活力水平及光镜下观察各组小鼠肾组织切片中草酸钙结晶体分布及组织病理改变。结果：与单纯结晶组相比,给予丹红注射液后的小鼠肾脏组织SOD、GSH和CAT显著上升,而MDA、血清尿素氮（BUN）及肌酐（Scr）水平、肾组织钙含量显著下降（P〈0．05）,肾组织草酸钙结晶沉积及肾脏病理组织损伤均低于单纯结晶组（P〈0．05）。结论：丹红注射液可能通过抑制过氧化应激途径减轻小鼠草酸钙结晶性肾损伤。     

输尿管支架管结壳患者尿液菌群的分布特点

目的探讨输尿管支架管结壳患者尿液菌群的分布特点。方法选取2018年10月至2019年3月在山东省立第三医院、山东大学齐鲁医院、济南市中心医院和济南市济钢医院就诊的35例输尿管支架管置入术后患者。纳入标准:年龄18~65岁;输尿管镜碎石术后留置内支架管4周。排除标准:尿液细菌培养阳性;严重肉眼血尿;近期口服抗生素;存在明显残石患者。本研究采用横断面研究方法(临床研究注册号为ChiCTR1800020025),根据有无支架管结壳将患者分为结壳组23例和无结壳组12例。收集拔管当日患者尿液行细菌16s DNA检测。使用UPARSE、UCHIME和RDP calssifier等软件分析两组患者尿液菌群分布特点,明确两组患者尿液中细菌种类总数、细菌丰度,以及丰度占比较大的细菌类别,比较两组患者尿液细菌种类、数量及细菌丰度的差异,明确结壳组患者尿液中丰度占比较大的细菌菌属。结果两组患者的年龄、性别、体质指数、置管侧别、内支架管型号及结石成分差异均无统计学意义(P>0.05)。16s DNA检测结果显示,结壳组丰度占比>1%的菌属数量为11个,丰度占比>0.01%的菌属数量为74个;无结壳组丰度占比>1%的菌属数量为7个,丰度占比>0.01%的菌属数量为11个,两组丰度占比>1%的菌属数量比较差异有统计学意义(t=5.12,P=0.000)。结壳组中菌属丰度占比前3位分别为乳杆菌属(23.1%)、拟杆菌属(18.8%)和未分级拟杆菌属(17.1%),非结壳组中菌属丰度占比前3位分别是为埃希菌-志贺菌属(32.2%)、肠球菌属(24.9%)和假单胞菌属(18.2%)。两组间差异最大的3种细菌是乳杆菌属(P=0.010),拟杆菌属(P=0.004)和未分级拟杆菌属(P=0.004)。结论支架管结壳患者尿液中细菌种类和数量都明显多于非支架管结壳患者。拟杆菌属细菌在支架管结壳患者尿液中的细菌种类丰度较大。     

草酸钙结晶肾损伤模型小鼠肾小管上皮细胞转分化的实验研究

目的:研究乙醛酸盐诱导所致草酸钙结晶肾损伤模型小鼠中肾小管上皮细胞转分化的发生情况。方法:选择C57BL/6J小鼠连续腹腔注射乙醛酸盐建立草酸钙结晶肾损伤模型,应用HE染色及冯库萨染色分别观察肾组织结构变化及钙盐沉积情况,并应用免疫荧光双染、Western-blot观察肾小管上皮细胞间充质转分化(epithelial mesenchymal transtion,EMT)的情况。结果:随着连续腹腔注射乙醛酸盐时间的延长,小鼠肾组织HE染色结果显示,近端肾小管管腔逐渐扩张,且肾小管上皮细胞逐渐出现肿胀及变形,基底膜逐渐裸露;冯库萨染色结果显示近端小管腔内黑色钙盐沉积逐渐增加;免疫荧光双染、Western blot结果均显示肾小管上皮标志E-cadherin及Pan-ck逐渐丢失,而间质标志α-SMA及Vimentin的表达则逐渐增加,Western blot检测结果显示随着乙醛酸盐干预的增强,Rho相关卷曲螺旋形成蛋白激酶(rho associated coiled coil forming protein kinase,ROCKI)表达也逐渐增加,且在干预第3天即达高峰。结论:乙醛酸盐诱导所致草酸钙结晶肾损伤模型早期即出现EMT,启动了肾间质纤维化的进程。     

The dual effect of urinary macromolecules on the crystallization of calcium oxalate endogenous in urine

Summary The nucleation-promoting and growth-inhibiting activities of urinary macromolecules on the crystallization of calcium oxalate endogenous in urine of stoneformers and normal controls were studied by freezing the ultrafiltrate and retentate fractions of concentrated whole urine (pH 5.3, 1,250 mosmol/kg). Among the normal controls, macromolecules nominally of 10–20 kDa showed nucleation-promoting and growth-inhibiting activities; the 5–10 kDa population was incapable of such effects but did cooperate with molecules >10 kDa in enhancing the effect. In the case of stone-formers, molecules in the nominal ranges of 5–10 kDa and 10–20 kDa when considered separately were not active in the aspects studied but collectively could cooperate to produce pronounced effects. Application of the test to urine ultrafiltrate reconstituted with polyanionic macromolecules recovered from urine indicated that molecules from stoneformers were more powerful than those from normal controls in bringing about promotion of nucleation and inhibition of growth of crystals from urinary calcium oxalate.     

Nucleation efficacy and flexural strength of novel leucite glass-ceramics

ObjectivesTo optimize the nucleation mechanism in leucite glass-ceramics to allow more efficacious glass-ceramic manufacture and improvements in microstructure and mechanical reliability.Materials and methodsAn alumino-silicate glass was designed and synthesized using melt quench methods. The glass was crushed and milled using various milling times (48–93 h) and spray drying. Nucleation and growth heat treatment schedules were applied to synthesize glass-ceramics. Glass/glass-ceramic powders and frit specimens were characterized using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), magic angle spinning nuclear magnetic resonance spectroscopy (MAS-NMR) and X-ray diffraction analyses (XRD). Glass-ceramic specimens were tested using the biaxial flexural strength test (BFS).ResultsApplication of defined nucleation heat treatments resulted in the synthesis of Na/Ca titanates. NMR indicated changes to the ²³Na glass spectra in the nucleated glass and TEM/EDX the presence of Na/Ca/Ti domains (<200 nm) within the leucite crystals and associated with the nucleation of the leucite phase. XRD confirmed the presence of a bulk leucite phase in the glass-ceramics. SEM/TEM confirmed the crystallization of the leucite phase (65.5–69.3%) in a thermally matched glass, in conjunction with the nano Na/Ca titanate phase. The leucite glass-ceramics resulted in a high BFS (255–268 MPa), with reduction in powder milling time prior to heat treatments having no significant effect on flexural strength and reliability (p > 0.05).SignificanceNa/Ca titanates were synthesized in leucite glass-ceramics for the first time and associated with its nucleation and efficacious growth. This nucleation optimization provides opportunities for more efficient manufacturing and microstructural/mechanical reliability improvements. Improved synthesis of high strength/reliable leucite glass-ceramics is useful for construction of esthetic minimally invasive restorations.     

Fine structure and mineral components of fibrous stonelike masses obtained from the human mesenteries

We investigated the fine structure and mineral components of 29 stonelike masses obtained from the mesenteries of four adult cadavers, using optical microscopy, backscattered electron imaging, scanning electron microscopy, energy-dispersive X-ray microanalysis, and X-ray diffraction. Although the overall appearance of the stonelike masses measuring about 5–20mm in diameter and 0.06–3.1g in dry weight was roughly grouped into smooth bulb- and uneven bulk-shaped types, all the calcified masses basically consisted of core and mantle regions. The smooth bulb-shaped masses had a broad mantle with many concentric rings, whereas the uneven bulk-shaped masses contained a large core. In their core regions, spherulitic and short bundle-shaped deposits composed of needle-shaped apatite crystals were mainly found among loose collagen fibers. Their mantle regions, on the other hand, showed the concentric structures of dense collagen fibers in the intra- and/or extrafibrous calcification with fine sandy grain-shaped deposits. The mineral elements were mainly Ca and P, and the major crystals were hydroxyapatite. Hexahedral whitlockite containing Mg was a minor component. The fiber-rich mantle regions showed lower calcification and lesser crystallization than the fiber-poor core region. When necrotic or some tumor adipose tissues and necrotic lymphoid tissues that might have been caused by some digestive diseases are recognized as foreign matter, their tissues occasionally will be calcified and grow into stonelike masses. These stonelike masses tend to occur more often in women than in men.     

Crystallization and preliminary X-ray diffraction analysis of human adenovirus

Replication-defective and conditionally replicating adenovirus (AdV) vectors are currently being utilized in ∼ 25% of human gene transfer clinical trials. Unfortunately, progress in vector development has been hindered by a lack of accurate structural information. Here we describe the crystallization and preliminary X-ray diffraction analysis of a HAdV5 vector that displays a short flexible fiber derived from HAdV35. Crystals of Ad35F were grown in 100 mM HEPES pH 7.0, 200 mM Ca(OAc)₂, 14% PEG 550 MME, 15% glycerol in 100 mM Tris-HCl 8.5. Freshly grown crystals diffracted well to 4.5 Å resolution and weakly to 3.5 Å at synchrotron sources. HAdV crystals belong to space group P1 with unit cell parameters a = 854.03 Å, b = 855.17 Å, c = 865.24 Å, α = 119.57°, β = 91.71°, γ = 118.08° with a single particle in the unit cell. Self-rotation and locked-rotation function analysis allowed the determination of the particle orientation. Molecular replacement, density modification and phase-extension procedures are being employed for structure determination.     

In vitro studies of epithelium-associated crystallization caused by uropathogens during urinary calculi development

Infectious urinary stones account for about 10% of all urinary stones. In 50% of cases urolithiasis is a recurrent illness, which can lead to the loss of a kidney if not properly treated. One of the reasons for recurrence of the disease may be the ability of bacteria to invade urothelial cells, persist in the host cells and serve as potential reservoirs for infection. Various uropathogens are associated with the formation of bacteria-induced urinary stones but Proteus mirabilis is the most commonly isolated (70%). An in vitro model was used in this study to analyze intracellular growth and crystallization in the presence of P. mirabilis, Klebsiella pneumoniae and Escherichia coli. Human ureter (Hu 609) and bladder (HCV 29) epithelial cell lines were infected with bacteria and incubated (3–72 h) in the presence of synthetic urine and amikacin to prevent extracellular bacterial growth. During the incubation the number of bacteria (CFU/ml) inside epithelial cells and the intensity of crystallization were established. Crystallization was determined as an amount of a calcium radioisotope. The chosen strains of uropathogens were able to invade both types of epithelial cells but the Hu 609 cells were invaded to a higher extent. However, crystallization occurred only in the presence of P. mirabilis strains which were invasive and urease-positive. The highest intensity of cell-associated crystallization was observed when the number of bacteria within the urothelium remained stable during the time of incubation. These results show that P. mirabilis has an ability to form crystals inside the host cells. Under these conditions bacteria are protected from antibiotic killing, which leads to persistent and recurrent infections. We also suspect that this phenomenon may be an important stage of kidney stones formation.