Comparison of shear stress acting on the severely worn anterior canine restored with 2 different restorations: An in vitro study

Aim: To compare fracture resistance of severely destructed mandibular canine under oblique loading restored with Richmond crown verses zirconia endocrown. Materials and method: 10 mandibular canine were endodontically treated and divided into 2 group of 5 each both the group were cut 2mm above the cement enamel junction one group received endo crown and second group received cast metal post and core, both the group were subjected shear force on UTM at cross head speed of 1 mm/min the results obtained were calculated in newton’s and statistical analysis was carried out. Results: Cast metal post and core (972.4±217.51N) showed better resistance to fracture than Richmond crown group (1180.6±168.87N).statistical analysis done using unpaired t test (P value =0.1818) which was which was statistically insignificant. Conclusion: endocrown showed better resistance to fracture from shear forces than cast metal post and core.&nbsp

Human chorionic gonadotropin: An update on its receptor binding regions

448-455Human chorionic gonadotropin (hCG), an important member of the glycoprotein hormone family, plays a crucial role in the establishment and maintenance of pregnancy. Glycoprotein hormones are all heterodimers composed of a common α subunit and a hormone-specific β-subunit noncovalently linked. These hormones exert their action by binding to specific receptors on the target cells. As both the subunits are involved in receptor binding, the binding sites on the hormones have to be topographical extending across both subunits. This article attempts to critically review the work on the receptor binding regions of hCG in the α- and β-subunits. A variety of approaches like chemical modification, site-directed mutagenesis, hormone chimeras and synthetic peptides have been used to map the receptor binding regions of hCG. There is agreement on the involvement of a number of regions in the α- and β- subunits in receptor binding but, there are also some contrasting observations. The regions 30-45 and 81-92 in the α-subunit appear to be involved in receptor binding whereas 8-22, 85-95, 93-100 and 100-110 are the consensus receptor binding regions in the β-subunit. Using disulphide peptides of the β-subunit as probes, recently the regions around Cys(9-57) and Cys(23-72) disulphide bonds have been identified to be important for receptor binding. After sifting through the available data two potential receptor binding sites in the β-subunit have been proposed

Disulphide bond reduction and S-carboxamidomethylation of PSP94 affects its conformation but not the ability to bind immunoglobulin

Prostate secretory protein of 94 amino acids (PSP94) is a small non-glycosylated, cysteine rich protein with a molecular mass of 10 kDa. It has also been referred to as β-microseminoprotein (β-MSP) and proteins homologous to it have been reported in a number of species. Comparison of the amino acid sequence of these proteins suggests that, it is a rapidly evolving protein. However, all the ten cysteine residues are well conserved in these homologues, indicating their possible role in maintaining the structure and function of these proteins. In the present study, PSP94 was purified from human seminal plasma and characterized further and it showed the presence of five disulfide bonds. Reduction of disulphide bonds of PSP94 led to significant changes in the secondary and tertiary structure of PSP94. CD of disulphide bond reduced PSP94 indicates an overall decrease in the beta sheet content from 79.8% to 46.4%. Tertiary structural changes as monitored by fluorescence quenching reveal that reduction of disulphide bonds of PSP94 followed by the modification of the free thiol groups leads to complete exposure of Trp32 and Trp92 and that one or more side chain carboxyl groups move closer to their indole side chains. Antibodies against native and modified PSP94 demonstrated that the changes following reduction of disulphide linkages are within the immunodominant region of the protein. Changes induced in the functional properties of PSP94, if any, by modification were investigated with respect to IgG binding as PSP94 has been reported to be similar to immunoglobulin binding factor purified from seminal plasma. A novel finding from this study is that both native PSP94 as well as modified protein have the ability to bind human IgG, suggesting the involvement of sequential epitopes of PSP94 in IgG binding

Biosynthesis of colloidal gold nanoparticles by <i style="mso-bidi-font-style:normal">Streptomyces</i> sp. NK52 and its anti-lipid peroxidation activity

969-972Gold nanoparticles (Au-NPs) were synthesized from chloroauric acid using cell free supernatant of <i style="mso-bidi-font-style: normal">Streptomyces sp. NK52 grown in nutrient broth. These nanoparticles were synthesized by varying pH and temperature of the reaction mixture and chloroauric acid concentration. The nanoparticles were characterized by spectrometry, X-ray diffraction, Scanning electron microscopy and energy dispersive spectrometry. Au-NP ranged from 10-100 nm in size and exhibited a polydispersive nature with various shapes like rods, hexagons, triangles, spheres. The diffraction peaks at 2θ = 38.1◦ and 44.5◦ could be assigned to the (1 1 1) and (2 0 0) planes of a faced centre cubic (fcc) lattice of gold. Au-NP showed 47% inhibition of lipid peroxidation in vitro. To the best of our knowledge, this is the first report on the rapid biosynthesis of Au-NP using cell free supernatant of Streptomyces sp. and its evaluation for anti-lipid peroxidation

Expression of Bioactive Callithrix jacchus Follicle-Stimulating Hormone in Pichia pastoris

Callithrix jacchus (common marmoset) is a New World primate monkey, used as an animal model in biomedical research. Marmoset-specific follicle-stimulating hormone (FSH) preparation is required to improve superovulation protocols and to develop homologous FSH monitoring assays in these monkeys. In this study, we document the large-scale expression of recombinant marmoset FSH in methylotropic yeast, Pichia pastoris. The recombinant preparation was found to be immunologically active in Western blotting and radioimmunoassay. The preparation displayed receptor binding ability in radioreceptor assay. Based on the receptor binding ability, the yield of fermentation was estimated to be 7.2 mg/L. FSH-induced cAMP assay and estradiol assay revealed that the recombinant hormone is able to induce signal transduction. Both immunological and in vitro biological activity of marmoset FSH was found to be comparable to purified human pituitary FSH, which served as reference hormone for these assays. Thus, the study suggests that a Pichia expression system can be used for large-scale expression of bioactive recombinant marmoset FSH

A device for occlusal plane determination

The correct orientation of the occlusal plane is the first and one of the important steps while recording jaw relationships in an edentulous patient. One of the most popular methods is to orient the occlusal plane to interpupillary line anteriorly and ala-tragus lines posteriorly which is usually accomplished by repetitive adjustment of the maxillary rim until a hand-held Fox's plane appears to be parallel to these lines. However, this process is time-consuming and error-prone. The eventual plane is almost always an educated guess, and this can be difficult for a new student. The device presented in this article marks the occlusal plane on wax rims parallel to interpupillary line anteriorly and the ala-tragus lines posteriorly, and thus, occlusal plane can be oriented in one simple step, thereby saving time and increasing efficiency of the operator