The Interaction Between Nephrocalcin and Tamm-Horsfall Proteins with Calcium Oxalate Dihydrate

Studies of crystals of calcium oxalate dihydrate (COD) grown by vapor diffusion from solutions contain-ing 5.1 x 10-7, 1.5 x 10-6, and 1.0 x 10-5 M nephrocalcin (NC), indicate that NC profoundly affects COD\u27s habit, size and structure. The decrease in COD size is such that at 1.0 x 10-5 M NC, the dimensions of the crystals are reduced about five-fold with respect to those of a NC-free control. In addition, the planes of the {101} form disappear, the original habit is lost, and the diffraction pattern deteriorates to such an extent that only the 200 reflections are recorded. The results are quite different when NC is adsorbed upon rigid substrates. Under such conditions, NC acts as a promoter and not as an inhibitor of growth and thus nucleates COD from its {100} planes. Consequently, COD grows systematically juxtaposed on NC. This effect is highly reproducible and stereospecific. COD crystals grown by vapor diffusion from solutions exposed to increasing concentrations of Tamm-Horsfall protein (THP) exhibit a drastic decrease in COD\u27s self-association. In sharp contrast with the results obtained for NC, precession photographs taken of COD samples exposed to 1.2 x 10-5 M THP do not show evidence of deterioration of COD diffraction patterns with respect to a protein-free control. Furthermore, THP neither nucleates COD, nor does it appear to influence its growth or habit even when THP is immobilized upon a rigid substrate

Three-dimensional biofabrication of an aragonite-enriched self-hardening bone graft substitute and assessment of its osteogenicity in vitro and in vivo

A self-hardening three-dimensional (3D)-porous composite bone graft consisting of 65 wt% hydroxyapatite (HA) and 35 wt% aragonite was fabricated using a 3D-Bioplotter®. New tetracalcium phosphate and dicalcium phosphate anhydrous/aragonite/gelatine paste formulae were developed to overcome the phase separation of the liquid and solid components. The mechanical properties, porosity, height and width stability of the end products were optimised through a systematic analysis of the fabrication processing parameters including printing pressure, printing speed and distance between strands. The resulting 3D-printed bone graft was confirmed to be a mixture of HA and aragonite by X-ray diffraction, Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy. The compression strength of HA/aragonite was between 0.56 and 2.49 MPa. Cytotoxicity was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro. The osteogenicity of HA/aragonite was evaluated in vitro by alkaline phosphatase assay using human umbilical cord matrix mesenchymal stem cells, and in vivo by juxtapositional implantation between the tibia and the anterior tibialis muscle in rats. The results showed that the scaffold was not toxic and supported osteogenic differentiation in vitro. HA/aragonite stimulated new bone formation that bridged host bone and intramuscular implants in vivo. We conclude that HA/aragonite is a biodegradable and conductive bone formation biomaterial that stimulates bone regeneration. Since this material is formed near 37°C, it will have great potential for incorporating bioactive molecules to suit personalised application; however, further study of its biodegradation and osteogenic capacity is warranted. The study was approved by the Animal Ethical Committee at Tongji Medical School, Huazhong University of Science and Technology (IACUC No. 738) on October 1, 2017

Phase Transitions of Calcium Oxalate Trihydrate and Epitaxy in the Weddellite-Whewellite System

The phase changes calcium oxalate trihydrate-weddellite, weddellite-calcium oxalate monohydrate and calcium oxalate trihydrate-whewellite are individually examined at the atomic level from a theoretical point of view; concomitantly the topological requirements necessary for phase stability are clarified for each structure type. In solution a sequential series of phase transitions according to the steps calcium oxalate trihydrate-weddellite-whewellite is not likely to be energetically favoured; direct conversion of calcium oxalate trihydrate to whewellite should be, instead, ordinarily expected. It is formally demonstrated that along two axial directions a set of atoms is in essentially identical positions in both weddellite and whewellite. This notwithstanding, it is concluded that epitactic catalysis cannot and should not be considered a common mechanism for the formation of whewellite from weddellite (and vice versa) or of kidney stones in general

Cavernous hemangioma: a term to be canceled

Many Authors still refer to “cavernous hemangioma”. To be correct, the term should indicate a tumor. Are cavernous hemangioma tumors? No. In a recent research Rootman et al. have demonstrated that CHs are non-infiltrating, focal venous malformations. They lack hyperplasia, that is, the cell turnover rate is not altered and they grow (when they do it, by an average 10 % per year) owing to phenomena of localized intravascular coagulation (LIC) and subsequent inflammation. Just like other Puig Type I venous malformations, they are (almost) excluded from the general circulation. Since isolated venous malformations of the orbit are not tumors, indications for surgery and, especially, the related informed consent must take this into consideration. Only those malformations presenting clear symptoms, like reduction in visual acuity and/or diplopia should be managed surgically. Another, less agreed on, indication is morphologically significant exophthalmos. Small, asymptomatic malformations, especially those located intraconally, can be just observed over time. Nonsurgical measures such as low molecular weight heparin could be used to stem episodes of LIC. Thus we believe that the term “cavernous hemangioma” should be canceled and replaced by Venous Malformation of the Orbit

Cavernous hemangioma: a term to be canceled

Many Authors still refer to “cavernous hemangioma”. To be correct, the term should indicate a tumor. Are cavernous hemangioma tumors? No. In a recent research Rootman et al. have demonstrated that CHs are non-infiltrating, focal venous malformations. They lack hyperplasia, that is, the cell turnover rate is not altered and they grow (when they do it, by an average 10 % per year) owing to phenomena of localized intravascular coagulation (LIC) and subsequent inflammation. Just like other Puig Type I venous malformations, they are (almost) excluded from the general circulation. Since isolated venous malformations of the orbit are not tumors, indications for surgery and, especially, the related informed consent must take this into consideration. Only those malformations presenting clear symptoms, like reduction in visual acuity and/or diplopia should be managed surgically. Another, less agreed on, indication is morphologically significant exophthalmos. Small, asymptomatic malformations, especially those located intraconally, can be just observed over time. Nonsurgical measures such as low molecular weight heparin could be used to stem episodes of LIC. Thus we believe that the term “cavernous hemangioma” should be canceled and replaced by Venous Malformation of the Orbit

High performance tunable piezoresistive pressure sensor based on direct contact between printed graphene nanoplatelet composite layers

This article details the development of a thin film piezoresistive screen printed pressure sensor on a flexible substrate using a composite ink based on functionalised graphene nanoplatelets (GNPs). The sensor operates through direct interfacial contact between two distinct films of the composite ink deposited over conductive substrates, without requiring any intermediate gap through spacers. The sensors showed consistent results and sensitivity forces ranging between 10 N to 2000 N. The piezoresistive range of the sensor can be tuned with the number of layers deposited per side

The infrahyoid flap: A comprehensive review of an often overlooked reconstructive method.

The infrahyoid flap is a myocutaneous pedicled flap mainly nourished by the superior thyroid vessels through the perforators of theinfrahyoidmuscles. This thin and pliableflap provides a skin island of about 7 by 4cm from the central part of the anterior neck. Theflapcan be transferred on its pedicle of superior thyroid artery and vein to reconstruct medium sized head and neck defects created aftercancer ablation. We have successfully used this flap in a series of 40 cases with no total flap loss and with 1 case of superficial skin necrosis. The aim of this review is to highlight the clinical usefulness of this pedicled flap even in the microvascular free flap era. A comprehensive review of the available literature reporting on the infrahyoid flap has been carried out using a web search. The history of the infrahyoid flap, the surgical technique with technical innovations, the clinical utility and limitations of this flap, are reported and discussed. Among the 7 larger series (cohort larger than 50 cases) a total of 956 flaps were performed, and the global success rate was 91.7\%, with failures being mainly related to partial skin necrosis, as the rate of total (skin and muscle) flap necrosis was only 1\%. This flap is reliable, easy to harvest during neck dissection, oncologically safe, it does carry a negligible donor site morbidity. This paper highlights how the infrahyoid flap can represent an excellent reconstructive solution in selected patients and head and neck sites

Sustainable Recycling of Insoluble Rust Waste for the Synthesis of Iron-Containing Perovskite-Type Catalysts

Insoluble rust waste from the scraping of rusted iron-containing materials represents a cheap, eco-friendly, and available source of iron. LaFeO3 perovskite-type powders were successfully prepared by solution combustion synthesis using rust waste from an electricity transmission tower manufacturer. Solution combustion synthesis enabled introduction of this insoluble iron precursor directly into the final product, bypassing complex extraction procedures. Catalytic activity in the propylene oxidation of the waste-derived LaFeO3 with stoichiometric Fe/La ratio was almost identical to the commercial iron nitrate-derived LaFeO3 , thus demonstrating the viability of this recycling solution. The amount of waste iron precursor was varied and its effect on the powder properties was investigated. A lesser stoichiometric amount of precursor produced a LaFeO3 -La2O3 binary system, whereas a higher stoichiometric amount led to a LaFeO3 -Fe2O3 binary system. Catalytic activity of iron-rich compositions in the propylene oxidation was only slightly lower than the stoichiometric one, whereas iron-poor compositions were much less active. This eco-friendly methodology can be easily extended to other iron perovskites with different chemical compositions and to other iron-containing compounds

Crystal Growth of Calcium Oxalate Monohydrate and Calcium Carbonate from Dilute Solutions

By controlling evaporation, calcium carbonate (calcite) is precipitated together with calcium oxalate monohydrate from equimolar (1 x 10-5 M) solutions of calcium chloride and sodium oxalate under decreasing (37.5° - 32.7°C) and increasing temperature (22°-42°, 22°-45°, 22°-50°C), and initial pH\u27s of 6.6 and 6, respectively. If, however, the pH of the solutions is, respectively, 8 and 8.5 and the temperature is 32°C, oxalate breaks down to carbonate and calcium precipitates solely as calcite. This process materializes as the pH of both solutions initially adjusts to about 7.5. Both the quality and the size of the crystals of calcite and calcium oxalate monohydrate varied markedly. Euhedral crystals of calcite, measuring in excess of 200 micrometers in cross-section, and grown at 37.5°C were remarkably ordered as shown by the lack of twinning, streaks and/or diffuseness around the diffracta, which is evidenced by single-crystal x-ray diffraction analysis. In contrast, calcium oxalate monohydrate was almost always disordered due to twinning along the (101) plane and never exceeded 100-150 micrometers along a coordinate axis