Sol-Gel Synthesis and in Vitro Characterization of Bioactive Glass Ceramics using Rice Husk Ash Waste Material

Glass-ceramics materials share many properties with both glass and more traditional crystalline ceramics. It is formed as a glass, and then made to crystallize partly by heat treatment. . Bioactive glass-ceramics describes the beneficial or adverse effects of glass-ceramic with living tissue , when placed in body. Bioactive glasses and glass-ceramics are more and more studied because of their surface chemical reactivity when in contact with body fluids [1–3]; by a complex mechanism of ions leaching and partial dissolution of the glass surface, the precipitation of bone-like apatite from the solution provides a strong chemical bonding with tissues. Since bioactive glasses and glass-ceramic are brittle materials, they are especially used in the field of small bone defects reconstruction, or as coatings on inert substrates for load-bearing prostheses. Since the discovery of bioglass by Hench et al. [4] in the early 1970s, various types of ceramic, glass and glass–ceramic have been proposed and used as bone replacement biomaterials [5-7]. Specifically, these biomaterials have found clinical applications as coating for prostheses, bone filler, vertebral substitution and, in a porous form, as bone substitutes [8-15]. Most of them are based on the SiO2–P2O5–CaO–Na2O system. Bonding between bioactive glass or glass–ceramic and the surrounding tissues takes place through the formation of a hydroxyapatite layer, which is very similar to the mineral phase of bone. When the bioactive glass is placed in contact with physiological fluids, this layer is formed through a complex ion-exchange mechanism with the surrounding fluids, known as bioactivity. This biologically-active layer of hydroxyapatite can form on the surface of glasses having a wide compositional range, and is considered as self by the surrounding living tissue; its presence is widely recognized to be a sufficient requirement for the implant to chemically bond with the living bone. Kokubo et al. [16] proposed the Tris-buffered simulated body fluid (SBF) for the in vitro study of bioactive glass and glass–ceramic, since its ion concentration is almost equal to that of human blood plasma. Since then, in vitro tests in SBF have been widely used as preliminary tests on new candidate materials showing bioactive properties. The ion leaching phenomenon involves the exchange of monovalent cations from the glass, such as Na+ or K+, with H3O+ from the solution, and thus causes an increase in the pH of the solution. It is known that osteoblasts prefer a slightly alkaline medium [17, 18], but it is also known that severe changes in pH can inhibit osteoblast activity and cause cell necrosis or apoptosis [19-21]. Different bioactive glass and glass ceramics have been synthesized in order to get desired mechanical, chemical properties by obtaining required microstructure. Some of common components used are Na2O, CaO, P2O5, SiO2 for synthesis of 45S5 and S53P4. In addition to these above components, varying composition of K2O, MgO , B2O3 are used to get 13-93, 3-04, 18-04, 23-04. There are some other glass and glass ceramics which also include ZnO, Ag and Al2O3. In current study of bioactive glass ceramic we are using rice husk ash as raw material for synthesis of silica, which is amorphous in nature. It is cheap, easily available source with high content of silic

The Mbd1-Atf7ip-Setdb1 pathway contributes to the maintenance of X chromosome inactivation.

BackgroundX chromosome inactivation (XCI) is a developmental program of heterochromatin formation that initiates during early female mammalian embryonic development and is maintained through a lifetime of cell divisions in somatic cells. Despite identification of the crucial long non-coding RNA Xist and involvement of specific chromatin modifiers in the establishment and maintenance of the heterochromatin of the inactive X chromosome (Xi), interference with known pathways only partially reactivates the Xi once silencing has been established. Here, we studied ATF7IP (MCAF1), a protein previously characterized to coordinate DNA methylation and histone H3K9 methylation through interactions with the methyl-DNA binding protein MBD1 and the histone H3K9 methyltransferase SETDB1, as a candidate maintenance factor of the Xi.ResultsWe found that siRNA-mediated knockdown of Atf7ip in mouse embryonic fibroblasts (MEFs) induces the activation of silenced reporter genes on the Xi in a low number of cells. Additional inhibition of two pathways known to contribute to Xi maintenance, DNA methylation and Xist RNA coating of the X chromosome, strongly increased the number of cells expressing Xi-linked genes upon Atf7ip knockdown. Despite its functional importance in Xi maintenance, ATF7IP does not accumulate on the Xi in MEFs or differentiating mouse embryonic stem cells. However, we found that depletion of two known repressive biochemical interactors of ATF7IP, MBD1 and SETDB1, but not of other unrelated H3K9 methyltransferases, also induces the activation of an Xi-linked reporter in MEFs.ConclusionsTogether, these data indicate that Atf7ip acts in a synergistic fashion with DNA methylation and Xist RNA to maintain the silent state of the Xi in somatic cells, and that Mbd1 and Setdb1, similar to Atf7ip, play a functional role in Xi silencing. We therefore propose that ATF7IP links DNA methylation on the Xi to SETDB1-mediated H3K9 trimethylation via its interaction with MBD1, and that this function is a crucial feature of the stable silencing of the Xi in female mammalian cells

Pharmacologic approaches against advanced glycation end products (ages) in diabetic cardiovascular disease

Advanced Glycation End-Products (AGEs) are signaling proteins associated to several vascular and neurological complications in diabetic and non-diabetic patients. AGEs proved to be a marker of negative outcome in both diabetes management and surgical procedures in these patients. The reported role of AGEs prompted the development of pharmacological inhibitors of their effects, giving rise to a number of both preclinical and clinical studies. Clinical trials with anti-AGEs drugs have been gradually developed and this review aimed to summarize most relevant reports

Chronic leptomeningitis and spinal intradural mass secondary to Alternaria infection in a patient with ventriculoperitoneal shunt

Fungal infection following placement of ventriculostomy or ventriculoperitoneal (VP) shunt is uncommon. We report the first case of Alternaria related central nervous system (CNS) shunt infection in a patient with CNS ependymoma manifesting as leptomeningitis and a spinal intradural mass. This case illustrates the diagnostic and management challenges

Soil Chemical Properties Under Conservation Agriculture and Cereal-Based Cropping System in Eastern Tarai of Nepal

Field experiments were conducted for four years (2014-2017) at five locations namely Salbani, Bhokraha, Simariya, Bhaluwa and Kaptanganj of Sunsari district to assess the changes in soil chemical properties under conservation agriculture (CA)-based practices in two cropping systems namely rice-kidney bean-maize at Salbani and rice-wheat at rest of the locations. In rice-wheat cropping system, there were four treatments: (1) conventional tillage (CT) for rice transplantation and subsequent wheat sowing, (2) conventional tillage rice transplantation followed by zero tillage (ZT) wheat, (3) unpuddled rice transplantation followed by zero tillage wheat, (4) zero tillage in both rice and wheat. Similarly, in rice-kidney bean-maize cropping system, there were four treatments; (1) conventional tillage for rice transplantation and sowing of both kidney bean and maize, (2) conventional tillage rice transplantation followed by zero tillage in both kidney bean and maize, (3) unpuddled rice transplantation followed by zero tillage in both kidney bean and maize, (4) zero tillage in all three crops. Soil samples were taken at initial and every year after rice harvest.The soil samples were analyzed for total nitrogen, available phosphorus, available potassium, pH and soil organic matter.Total nitrogen (N) showed a slightly decreasing trend in the first three years and showed a slight increase at the end of experiment under ZT in all locations. The total N under ZT changed from 0.12 to 0.13%, 0.05 to 0.06%, 0.10 to 0.12%, 0.11 to 0.08% and 0.09 to 0.13% in Salbani, Bhokraha, Simariya, Bhaluwa and Kaptanganj, respectively.  All locations showed the positive values of available potassium; Salbani  revealing considerable change of 64.3 to 78.5 mg/kg in CT while 68.4 to 73.3 mg/kg in ZT condition. The treatment where rice was transplanted in unpuddled condition and zero tilled to wheat, had a mean value of available phosphorus and potassium as 87.3 and 81.9 mg/kg respectively. Soil pH ranged from 4.8 to 7.1 in CT while it was 5.2 to 6.8 in ZT across the locations. The change in soil organic matter in CT of all locations except Salbani was narrower as compared to ZT

Učinak vrućice uzrokovane endotoksinom bakterije E. coli na farmakokinetiku i doziranje ceftriaksona u ovaca (Ovis aries).

The effect of fever was studied on the pharmacokinetics of ceftriaxone (CTRX) following intravenous administration at the rate of 50 mg/kg b.m. in Chhotanagpuri sheep. Fever was induced by intravenous administration of E. coli serovar O126:B8 lipopolysaccharide, and plasma CTRX concentration was estimated by HPLC. The plasma drug concentration versus time curve best fitted a two compartment open model. The maximum plasma drug concentration was 16.33 per cent lower in febrile sheep (FS) in comparison to normal sheep (NS). In FS, t1/2α was lower, while t1/2β was higher than in NS. Vdarea and P: C ratio was higher in FS, but ClB and AUC did not differ significantly between the two groups. The results of the present study indicate that CTRX has greater distribution in the peripheral compartment during pyrexia. High values of K12/K /K21 ratio also indicated rapid drug distribution in various body fluids and compartments. The suitable dosage regimen of CTRX in FS by the intravenous route was calculated to be 15 mg/kg b.m. at a 5 h interval.Istraživan je učinak vrućice na farmakokinetiku ceftriaksona (CTRX) nakon njegove intravenske primjene u dozi od 50 mg/kg tjelesne mase u ovaca pasmine Chhotanagpuri. Vrućica je bila uzrokovana intravenskom primjenom lipopolisaharida serovara O126:B8 bakterije E. coli. Koncentracija cefriaksona u plazmi bila je određivana visokotlačnom tekućinskom kromatografijom. Koncentracija lijeka u plazmi u odnosu na vremensku krivulju bila je najsličnija modelu dvaju odjeljaka. Najveća koncentracija lijeka bila je 16,33% manja u febrilnih ovaca u odnosu na nefebrilne. U febrilnih je ovaca t1/2α bio manji, a t1/2β veći nego u nefebrilnih. Prividni volumen raspodjele (Vdarea) i omjer P:C bili su veći u febrilnih ovaca dok se ClB (ukupni klirens lijeka iz organizma) i AUC (površina ispod koncentracijske krivulje lijeka u plazmi) nisu značajno razlikovali između dviju skupina. Rezultati ovog istraživanja naznačuju da ceftriakson ima bolju raspodjelu u perifernom odjeljku za vrijeme vrućice. Velike vrijednosti odnosa K12/K21 također upućuju na brzu raspodjelu lijeka u različitim tjelesnim tekućinama i odjeljcima. Izračunato je da je ceftriakson u febrilnih ovaca najbolje davati intravenski u dozi od 15 mg/kg tjelesne mase u razmaku od pet sati