Search results for "Calcium"

Type V collagen counteracts osteo-differentiation of human mesenchymal stem cells

2014

In search of novel gene signatures for osteo-differentiation of mesenchymal stem cells (MSCs), we submitted cDNA preparations from undifferentiated and differentiating MSCs to differential display- and semiquantitative-PCR and found down-regulation of COL5A1 in osteo-induced cultures at days 21 and 28, when the mineralized matrix accumulates. We also cultured osteo-differentiating MSCs onto type V collagen substrates and found a decrease in the accumulation of extracellular calcium compared to those grown in uncoated flasks. To our knowledge, this is first evidence that type V collagen might represent a stromal component that impairs osteogenesis.

Association of low 25-hydroxyvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early puberta…

2003

Background: Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] and their effects on bone mass in children. Objective: We studied the associations of serum 25(OH)D and intact PTH (iPTH) with bone mineral content (BMC) and bone mineral density (BMD) at different bone sites and the relation between serum 25(OH)D and iPTH in early pubertal and prepubertal Finnish girls. Design: The subjects were 10‐12-y-old girls (n = 193) at Tanner stage 1 or 2, who reported a mean (± SD) dietary calcium intake of 733 ± 288 mg/d. 25(OH)D, iPTH, tartrate-resistant acid phosphatase 5b (TRAP 5b), urinary calcium excretion, BMC, areal BMD, and volumetric BMD were asses…

Modification of a commercial atomic force microscopy for low-noise, high-resolution frequency-modulation imaging in liquid environment.

2011

A key issue for high-resolution frequency-modulation atomic force microscopy imaging in liquids is minimizing the frequency noise, which requires a detailed analysis of the corresponding noise contributions. In this paper, we present a detailed description for modifying a commercial atomic force microscope (Bruker MultiMode V with Nanoscope V controller), aiming at atomic-resolution frequency-modulation imaging in ambient and in liquid environment. Care was taken to maintain the AFMs original stability and ease of operation. The new system builds upon an optimized light source, a new photodiode and an entirely new amplifier. Moreover, we introduce a home-built liquid cell and sample holder …

Direct Visualization of Molecule Deprotonation on an Insulating Surface

2012

Elucidating molecular-scale details of basic reaction steps on surfaces is decisive for a fundamental understanding of molecular reactivity within many fields, including catalysis and on-surface synthesis. Here, the deprotonation of 2,5-dihydroxybenzoic acid (DHBA) deposited onto calcite (101;4) held at room temperature is followed in situ by noncontact atomic force microscopy. After deposition, the molecules form two coexisting phases, a transient striped phase and a stable dense phase. A detailed analysis of high-resolution noncontact atomic force microscopy images indicates the transient striped phase being a bulk-like phase, which requires hydrogen bonds between the carboxylic acid moie…

THERAPEUTIC OPTIONS IN OSTEOPOROSIS

2010

Pro-Degradant Activity of Naturally Occurring Compounds on Polyethylene in Accelerate Weathering Conditions

2019

In this work, naturally occurring compounds, such as Vitamin E (VE) and Ferulic Acid (FA), at high concentrations, have been considered as pro-degradant agents for Low Density Polyethylene (PE). However, all obtained results using the naturally occurring molecules as pro-oxidant agents for PE have been compared with the results achieved using a classical pro-oxidant agent, such as calcium stearate (Ca stearate) and with neat PE. The preliminary characterization, through rheological, mechanical and thermal analysis, of the PE-based systems highlights that the used naturally occurring molecules are able to exert a slight plasticizing action on PE and subsequently the PE rigidity and crystalli…

Changes in physicochemical properties of soils in the area affected by lime industry

2016

Lime and cement industry belongs to the best developed branches of industry in Opole Voivodeship. The plants are located in eastern and central part of the province, in the vicinity of the city of Opole and the towns of Krapkowice and Strzelce Opolskie due to the location of the resources of calcareous raw materials (limestones and marls).The impact of lime and cement industry on the natural environment, especially soils, was studied by many authors, but these works do not concern the Province of Opole, which is one of the main centers of lime and cement industry in Poland for centuries. The article is an attempt to show changes in physicochemical properties of soils being under long lastin…

Aplidin® induces JNK-dependent apoptosis in human breast cancer cells via alteration of glutathione homeostasis, Rac1 GTPase activation, and MKP-1 ph…

2006

Aplidin® is an antitumor agent in phase II clinical trials that induces apoptosis through the sustained activation of Jun N-terminal kinase (JNK). We report that Aplidin® alters glutathione homeostasis increasing the ratio of oxidized to reduced forms (GSSG/GSH). Aplidin® generates reactive oxygen species and disrupts the mitochondrial membrane potential. Exogenous GSH inhibits these effects and also JNK activation and cell death. We found two mechanisms by which Aplidin® activates JNK: rapid activation of Rac1 small GTPase and downregulation of MKP-1 phosphatase. Rac1 activation was diminished by GSH and enhanced by L-buthionine (SR)-sulfoximine, which inhibits GSH synthesis. Downregulatio…

Rho GTPases are over-expressed in human tumors.

1999

Small GTPases of the Rho family are involved in the regulation of a variety of cellular processes, such as the organization of the microfilamental network, cell-cell contact and malignant transformation. To address the question of whether Rho proteins are involved in carcinogenesis in man, we compared their expression in tumors from colon, breast and lung with that of the corresponding normal tissue originating from the same patient. As shown by Rho-specific 32P-ADP-ribosylation, as well as Western-blot analysis, the amount of RhoA protein was largely increased in all 3 types of tumors tested. The most dramatic differences in the expression of Rho GTPases were observed in breast tissue. All…

Maxillary sinus lift with intraoral autologous bone and B ? Tricalcium Phosphate : histological and histomorphometric clinical study

2007

Introduction: Rehabilitation with implants in the upper maxilla often implies a challenge due to the shortage and quality of the remaining bone. Different kinds of grafts have been described in an endeavour to solve these problems. Aim: The purpose of this study was to assess the osteoconduction potential of an autogenous bone and B-Tricalcium Phosphate mixture, in the treatment of atrophic upper maxillae. Materials and Methods: 22 patients were treated using the "sinus lift" technique. All patients had residual bone equal to or greater than 5 mm, the sinus was lifted, bone grafted and implants installed during the same surgical procedure (autologous bone and B- Tricalcium Phospahate). Duri…