In vitro effect of nonindole compounds on oxidative activity of ceruloplasmin

1959 ◽  
Vol 14 (3) ◽  
pp. 363-367 ◽  
Author(s):  
K. M. Hanson ◽  
D. C. Austin ◽  
M. H. Aprison

It has already been shown that, in addition to ascorbic acid, 5-hydroxytryptamine and several other 5-hydroxyindole compounds affect the oxidative activity of ceruloplasmin and serum oxidase. Therefore, an in vitro study of the effect of several other normal metabolites and drugs on this enzyme system was undertaken. It was found that the compounds which affect this reaction fall into two classes. One group (cysteine, penicillamine and ascorbic acid) reacts with the oxidized form of the substrate reducing it back into the original compound, thereby producing a lag period in the reaction. The other group (DOPA and iproniazid) inhibits the reaction, probably by competing with the substrate molecules for the enzyme site. Submitted on November 17, 1958

Author(s):  
Barbara Kochańska ◽  
Mirela Łukaszewska ◽  
Jolanta Ochocińska

The aim of this work was to evaluate of hydrolytic activity of whole saliva using chitosan ascorbate as a substrate. In this aim, the concentrations of N-acetyl-D-glucosamine were determined in saliva before addition of chitosan ascorbate, directly after addition and during incubation with chitosan ascorbate by 20 hrs. In this in vitro study were used sterile chitosan ascorbate in the form of powder. Chitosan was obtained from krill chitin. The ratio of ascorbic acid to chitosan was 1:1. The unstimulated whole saliva showed the hydrolytic activity in the presence of the chitosan ascorbate as a substrate.


1970 ◽  
Vol 9 (4) ◽  
pp. 223-230
Author(s):  
Krishna Prasad Parvathaneni ◽  
Beena Rani Goel ◽  
Bharani Devi Parvathaneni

The main advantage of nickel titanium instruments is that they permit canal preparation with less transportation and ledging. Hand used Ni-Ti and rotary Ni-Ti instruments have a wider range of elastic deformation and greater flexibility. The aim of the present study was to evaluate and compare the preparation time, loss of working length, apical transportation, instrument deformation and fracture with stainless steel, Ni-Ti hand and Ni-Ti rotary endodontic instruments. Fifty freshly extracted human mandibular molars with curved roots were collected and stored in 10% formalin. The samples were divided into 3 groups of 15 each. The access opening was made for each tooth and the biomechanical preparation was carried out using crown down pressureless technique in all the groups. Group I was instrumented with stainless steel files, group II with hand Ni-Ti and group III with Ni-Ti rotary files. The preparation time to enlarge each canal was recorded in minutes and seconds, which included only active instrumentation. Following preparation, the final length of each canal was subtracted from the original length to give the loss of working length. SEM photographs of the deformed and fractured instruments were taken. The apical transportation was measured using computer software (Microdraw 4.1). The readings were noted and statistically analyzed.The results of this in vitro study showed that the mean preparation time was less with Ni- Ti rotary (1.85 min) when compared to hand Ni-Ti (6.33) and stainless steel files (6.73), which was statistically significant. The loss of working length was more for stainless steel group which was statistically significant (P<0.05) when compared with the other 2 groups.One instrument in stainless steel and one in Ni-Ti rotary files were fractured. Only one instrument in stainless steel file deformed permanently. Apical transportation was found to be greater in stainless steel group than other groups (P<0.01) which was statistically significant. Considering the parameters in this study, Ni-Ti rotary files proved to perform better than the other two groups. Key words: Canal preparation; crown-down pressure less technique; double exposure radiographic technique. DOI: 10.3329/bjms.v9i4.6689Bangladesh Journal of Medical Science Vol.09 No.4 July 2010 pp.223-230


2020 ◽  
Vol 14 (02) ◽  
pp. 189-193 ◽  
Author(s):  
Passent Aly ◽  
Cherif Mohsen

Abstract Objectives The integration of computer-aided design and manufacturing technologies in diagnosis, treatment planning, and fabrication of prosthetic restoration is changing the way in which prosthodontic treatment is provided to patients. The aim of this study was to compare the accuracy of three-dimensional (3D) printed casts produced from the intraoral scanner using stereolithographic (SLA) 3D printing technique, their digital replicas, and conventional stone casts. Materials and Methods In this in vitro study, a typodont of maxillary and mandibular arches with full dentate ivory teeth was used as a reference cast. The typodont was digitized using Trios 3Shape intraoral scanner to create digital casts. The digital files were converted into 3D printed physical casts using a prototyping machine that utilizes the stereolithography printing technology and photocurable polymer as printing material. Linear measurements (mesiodistal and occlusocervical) and interarch measurements (intercanine and intermolar) were made for digital and prototyped models and were compared with the original stone casts. The reference teeth were canines, first premolars and second premolars in the maxillary and mandibular arches on the right and left sides. The measurements on printed and conventional casts were done by digital caliper while on digital casts; Geomagic Qualify software was used. Statistical Analysis One-way analysis of variance (ANOVA) was used to compare measurements among groups. Results Digital casts showed significantly higher error than the other two groups in all linear and interarch measurements. The mean errors of the digital cast in occlusocervical (OC) and mesiodistal (MD) measurements (0.016 and 0.006, respectively) were higher compared with those in the other two groups (OC, 0.004 and 0.007 and MD, 0.003 and 0.005 [p < 0.0001 and p = 0.02, respectively]). Also, digital mean error in intermolar width (IMW) and intercanine width (ICW) (0.142 and 0.113, respectively) were greater than the other two groups (IMW, 0.019 and 0.008 and ICW, 0.021 and 0.011 [p < 0.0001]). However, the errors were within the acceptable clinical range. Conclusion The 3D printed casts may be considered as a substitute for stone casts with clinically acceptable accuracy that can be used in diagnosis, treatment planning, and fabrication of prosthetic restorations.


2003 ◽  
Vol 353 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Pier Andrea Serra ◽  
Rossana Migheli ◽  
Gaia Rocchitta ◽  
Maria G. Taras ◽  
Maria P. Mura ◽  
...  

2021 ◽  
Vol 10 (1) ◽  
pp. 126-131
Author(s):  
Zakaria Karimi ◽  
Houda Saoui ◽  
Majid Sakout ◽  
Faiza Abdallaoui

Objectives: The aims of this in vitro study was to investigate the effects of bleaching agents commonly used in micromorphology of the enamel surface and to assess the effect of concentration and of adding fluoride in the bleaching agents. Methods: Sixty freshly extracted intact teeth were stored in distilled water. One half of each tooth was served as control, the other part was treated with bleaching agent. Samples were randomly divided into six groups of ten, according to the bleaching agents: G1- at-home-CP10; G2- at-home-CP16; G3- at-home-CP22; G4- in-office-CP35; G5- in-office-HP40 with fluoride; G6- in-office-HP40 without fluoride. Enamel specimens for each group were then submitted to a quantitative scanning electron microscopy. Number of pores and their diameter were measured to assess porosity of enamel surface. Results: SEM analysis revealed enamel surface porosity after bleaching. Significant increase in number and major diameter of pores in bleached samples (p<0.001) were observed. The comparison between samples treated with 10% PC and samples treated with 22% PC showed significant increase in number of pores (p=0.006) and major diameter (p=0.001) from samples treated with 22% PC. Statistical analyses showed significant increase in the number of pores (p=0.006) from samples treated with 40% HP without fluoride compared to samples treated with 40% HP containing fluoride. Conclusions: Bleaching products with low concentration cause less porosity at surface of the enamel compared to concentrated products. Adding fluoride in the bleaching agent appears to reduce porosity of enamel surface.


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