Glutaraldehyde Group Research Articles

Preparation of Cross-Linked Bovine Tendon Acellular Fibers and Study of Their Biophysical and Chemical Properties

To explore the effect of glutaraldehyde (GA) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) cross-linking on the biophysical and chemical properties of acellular scaffold to better provide suitable donor materials for tendon reconstruction. GA and EDC with different concentrations and action time gradients were used to cross-link the acellular scaffold. By detecting the collagen content in the cross-linked scaffold and the cytotoxicity, the cross-linking scheme with minimal damage to the scaffold and minimal cytotoxicity was explored for subsequent studies. The biomechanical properties (durability, elastic modulus, stressmax) of the scaffolds in GA, EDC, acellular scaffold, and tendon groups were compared, and the scaffold rat models were constructed to further evaluate their in vivo histocompatibility. Under different concentration gradients, the collagen content of the scaffolds in the GA and EDC groups had no obvious difference. When 0.5% GA was cross-linked for 24 h, and the mass ratio of EDC (1:2) was cross-linked for 4 h, the inhibition rate of the scaffold extract on fibroblasts was the lowest. In the mechanical property test, the Stressmax, durability, and elastic modulus of the cross-linked acellular scaffolds were significantly improved than those before cross-linking, and the elastic modulus of the EDC acellular scaffold was similar to that of the bovine tendon. In the compatibility test, compared with the acellular scaffold group, fibroblast activity in the GA group decreased obviously, and the scaffold implanted in rat models led to a persistent chronic inflammatory reaction. However, cells in the EDC group could maintain good activity. Moreover, the scaffold had good compatibility with rats and did not cause an obvious inflammatory reaction. EDC cross-linking scheme will not damage the acellular scaffold, and the cytotoxicity of the obtained scaffold is controllable. Additionally, EDC cross-linked acellular scaffold has mechanical properties similar to normal tendons and excellent histocompatibility.

A Comparative Evaluation of the Effect of Ozonated Water and 2% Glutaraldehyde as disinfectants on the physical properties of polyvinyl siloxane impression material – An Invitro study

Aims: To compare the efficacy of ozone water and 2% glutaraldehyde in disinfecting polyvinyl siloxane impression and the effect of both disinfectants on the wettability, dimensional accuracy and surface detail reproduction of the material. Settings and Design: In vitro – comparative study Material and Methods: Samples (N =108) were subjected to disinfection either with 2% glutaraldehyde (group 1) or ozone water (group 2) for 15 minutes. To evaluate the efficacy, the samples were inoculated with Streptococcus mutans [ATCC 25175], Staphylococcus aureus [ATCC 25923] and Candida albicans [ATCC 10231]. Reductions in the number of microbial population after disinfection were determined by counting the colony forming units (CFU). The contact angle measurements on the impression surface were used to determine the wettability. Dimensional accuracy and surface detail reproductions of the samples were assessed with a stereomicroscope of 4X magnification. Statistical analysis used: paired t- test and chi-square test were used. Results: The efficacy of both disinfectants in reducing the microbial count found to be comparable. Both the disinfectants reduced the contact angle which improved the wettability of the material. Disinfection with 2% glutaraldehyde showed significant alteration in dimensional accuracy and surface detail reproduction (p<0.05) when compared to samples disinfected with ozone water, which preserves the dimensional accuracy and surface details. Conclusions: Ozone water treatment was identified as a potential method for the disinfection of polyvinyl siloxane impression as it increased the wettability of the material, showed least dimensional changes and preserved surface details more accurately.

Evaluating the shortest and most efficacious decontaminating method for endodontic files in Pediatric dentistry

Aim: To compare and evaluate the effectiveness of various pre-sterilizing techniques used for the sterilization of endodontic files used intermittently in between patients in the dental operatory.
 Materials and Methods: The current study involved investigating the effectiveness of 4 methods of pre-sterilizing endodontic files: Control group: no sterilization procedure was performed; Group A- chemical sterilization (with Glutaraldehyde), Group B- Autoclave, Group C- Ultraviolet Chamber and Group D- Ethanol. A total of 50 endodontic files for 10 patients indicated for pulp therapy in primary deciduous molars with 4 root canals each were selected for the study. After access opening, pulp was extirpated by 5 files each per patient.
 After access opening, 40 root canals in 10 patients were cleaned and shaped using conventional techniques. Each file was then allotted to each group and sterilized by the above mentioned methods and assessed for sterility by putting it in eppendorf tubes containing Brain Heart Infusion (BHI) broth and incubating it at 37oC for 24 hours. The bacterial cultures were then measured for their optical densities using the spectrophotometer. 
 Results: Maximum decrease in microbial cultures was noted in the Autoclave group followed by the Glutaraldehyde group with a non-significant difference. Ethanol and UV sterilization had non- significant results among them but were significantly different from Autoclave and Glutaraldehyde.
 Conclusion: Pre sterilization of files is an important step especially in these times and can be easily achieved by various methods.

Comparative study of poly tannic acid functionalized magnetic particles before and after modification for immobilized penicillin G acylase

In this work, Fe3O4 nanoparticles (NPs) was synthesized by inverting microemulsion method. After that, based on the physical and chemical properties of tannic acid (TA), poly tannic acid (PTA) was coated on Fe3O4 NPs surface. Fe3O4 NPs coated with PTA, on the one hand, was used to immobilize Penicillin G acylase (PGA) by physical adsorption. On the other hand, it was modified by glutaraldehyde (GA). GA grafting rate (Gr-GA ) was optimized, and the Gr-GA was 30.0% under the optimum conditions. Then, through the Schiff base reaction between the glutaraldehyde group and PGA amino group, this covalent immobilization of PGA was further realized under mild conditions. Finally, the structures of every stage of magnetic composites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibration magnetometer (VSM) and transmission electron microscopy (TEM), respectively. The results indicated that the enzyme activity (EA), enzyme activity recovery (EAR) and maximum load (ELC) of the immobilized PGA were 26843 U/g, 80.2% and 125 mg/g, respectively. Compared to the physical immobilization of PGA by only coating PTA nanoparticles, further modified nanoparticles by GA showed higher catalytic stability, reusability and storage stability.

Prevention of the calcification of porcine heart valve leaflets implanted subcutaneously in rats by an interleukin-8 receptors antagonist (SCH527123)

Bioprosthetic heart valve calcification may result from interactions between the host's immune system and the glutaraldehyde (GA)-fixed tissue that makes up the leaflets. We hypothesized that antagonizing interleukin-8 (IL-8) receptors, CXCR-1 and CXCR-2, may prevent the calcification of GA-fixed porcine aortic valves implanted subcutaneously in rats. Three-week-old Sprague Dawlay males were transplanted with 2 aortic valve leaflets isolated from pigs and implanted into the dorsal wall. Four groups of 3–4 rats (6–8 independent leaflets each time) were compared: glutaraldehyde (GA)-free leaflets, GA-fixed leaflets (0.6% GA for 24 h before implantation), GA-fixed leaflets and treatment of rats with 1 mg/kg SCH5217123 (a CXCR1/2 antagonist) injected once a day locally subcutaneously (SC) or intraperitoneally (IP). Fourteen days later, rats underwent blood leukocyte count and CT-scan, before porcine leaflets explantation and histology and biochemistry analyses. As expected, strong calcification of ectopic valves was induced by the GA. However, we observed a significant about 40% decrease in this effect when rats were treated with the SCH527123. These effects were confirmed by CT-scan acquisitions and Alizarin red staining of valves. Besides, GA pre-incubation of valves significantly increased leukocytes count in rat blood, an effect that is significantly prevented by IP SCH527123 (6.9, 16.6 and 6.8 × 10 9 /L in the GA-free, GA and GA + IP SCH527123 groups respectively, P = 0.0129). Immunohistochemistry of ectopic valves highlighted higher infiltration of CD3 (lymphocytes) and CD68 (macrophages) cells in the GA group compared to the GA-free and GA + SCH527123 groups. Therefore, the calcification of GA-fixed porcine aortic valve leaflets, implanted subcutaneously in rats, is significantly prevented by antagonizing IL-8 receptors with SCH527123. This effect might partly result from an inhibition of the GA-induced leukocytes activation and recruitment into the graft tissue.

Glutaraldehyde (GLA) Loaded Albumin Nanoparticles Mediated p53 Targeting Cervical Cancer

Nano-albumin-mediated different doses of glutaraldehyde (GLA) were used in cervical cancer nude mice to observe the expression of p53, Bax protein and genes in transplanted tumors and explore the mechanism of GLA on cervical cancer. Cervical cancer Hela cells were cultured. 20 nude BALB/C-nu female mice were selected to establish transplanted tumor models and separated into control group (n = 5) and GLA group (n = 15). Grouping of glutaraldehyde (GLA)-loaded human serum albumin nano-carriers (GLA-HSANC) drugs was done and separated into GLA low-dose (0.06 µmol/mg) and medium-dose (0.12 µmol/mg) and high-dose group (0.18 µmol/mg) followed by assessing xenograft tumor apoptosis, p53 and Bax expression and Hela cell cycle. The shape and structure of various organs of nude mice were normal. The volume of transplanted tumors, tumor markers CA125 and CEA in different dose groups were lower than the control group. The tumor inhibition rate, growth inhibition rate of transplanted tumors, the number of apoptotic cells in transplanted tumors, p53, Bax protein and mRNA expression were all opposite in a dose dependent manner. Compared with the control group, the number of cells in G1 phase of other groups was higher with lower cell number in S phase dose-dependently. GLA nano-albumin particles-mediated p53 targeting cervical cancer tumors can significantly promote tumor cell apoptosis possibly via upregulating p53 and Bax, and increasing cells in G1 phase.

Evaluation of Cymbopogon Citratus as Disinfectant and its Effect on the Dimensional Stability of the Resultant Gypsum Casts: An in Vitro Study.

BACKGROUND AND AIM: Proper disinfection of impression is probably the most important procedure for dental lab to render it safe for further handling without affecting the accuracy of fine details. In light of these intermingling facts, author aimed to 1) investigate the antimicrobial effect of Cymbopogon citratus on selected microorganism colony and 2) the effect of the disinfectant solution on the dimensional accuracy of the resultant gypsum casts. MATERIALS & METHOD: Initially, tropicalgin Alginate was mixed and total of 20 impressions of the alginate and painted with bacterial colonies. Swabs were further subjected to culture and sensitivity tests for predetermined bacterial strains. Alginate impressions were immersed in glutaraldehyde 2% and Cymbopogon Citratus 30% for 10 minutes (ten each). The swabs were wiped on glass Petri dish and inoculated. The colonial growth was transferred to the glass slide for Gram staining which confirmed presence of Staphylococcus aureus, Streptococcus mutans and Candida albicans in control group. Cross-arch distance between 16 and 26 of the poured samples were compared with the cross arch distance in the typhodont teeth using digimatic vernier caliper. RESULT: Statistical analysis was attempted using SPSS version 22.0. The results of dimensional accuracy of 2% Glutaraldehyde (Group A) mean reading was 55.114, Variance =0.00687 and standard deviation were 0.8289 obtained. The results of dimensional accuracy of 30% Cymbopogan Citratus (Group B) mean reading was 55.403, Variance = 0.0268 and standard deviation were 0.16384 obtained. CONCLUSION: Within the limitations of the study, authors concluded that anti-microbial efficacy of 2% Glutaraldehyde was less in comparison to 30% Cymbopogon Citratus on resultant selected microorganism in this study and dimensional accuracy was superior in Cymbopogan citratus in comparison to glutaraldehyde.

Decellularized nerve extracellular matrix/chitosan crosslinked by genipin to prepare a moldable nerve repair material.

Decellularized nerve extracellular matrix (NECM) composited with chitosan are moldable materials suitable for spinal cord repair. But the rapid biodegradation of the materials may interrupt neural tissue reconstruction in vivo. To improve the stability of the materials, the materials produced by NECM and chitosan hydrogels were crosslinked by genipine, glutaraldehyde or ultraviolet ray. Physicochemical property, degradation and biocompatibility of materials crosslinked by genipin, glutaraldehyde or ultraviolet ray were evaluated. The scaffold crosslinked by genipin possessed a porous structure, and the porosity ratio was 89.07 + 4.90%, the average diameter of pore was 85.32 + 5.34 μm. The crosslinked degree of the scaffold crosslinked by genipin and glutaraldehyde was 75.13 ± 4.87%, 71.25 ± 5.06% respectively; Uncrosslinked scaffold disintegrated when immerged in distilled water while the scaffold crosslinked by genipin and glutaraldehyde group retained their integrity. The scaffold crosslinked by genipin has better water absorption, water retention and anti-enzymatic hydrolysis ability than the other three groups. Cell cytotoxicity showed that the cytotoxicity of scaffold crosslinked by genipin was lower than that crosslinked by glutaraldehyde. The histocompatibility of scaffold crosslinked by genipin was also better than glutaraldehyde group. More cells grew well in the scaffold crosslinked by genipin when co-cultured with L929 cells. The decellularized nerve extracellular matrix/chitosan scaffold crosslinked by the genipin has good mechanical properties, micro structure and biocompatibility, which is an ideal scaffold for the spinal cord tissue engineering.

Assessment of Effect of Different Sterilization Agents on Dimensional Accuracy of Different Impression Materials in Implant Prosthesis - An In vitro Study.

Aim:Sterilization of impression materials is of paramount importance. The present study was conducted to compare the effect of different disinfectants on dimensional accuracy of elastomeric impression materials used for implant prosthesis and other routine treatments.Materials and Methods:The present study was conducted with polyvinyl siloxane (PVS) (regular body), PVS (medium body), PVS (heavy body), and polyether (medium body) impression materials. Glutaraldehyde (2%) and sodium hypochlorite (NaOCl, 0.525%) were the disinfectant solutions employed in the study. After 16 h, the specimens were measured under Leica WILD stereomicroscope and dimensions were compared with master die.Results:The dimensional change in the Controls, 2% glutaraldehyde (Group I), and 0.525% NaOCl (Group II) was non significant where as Group III and Group IV showed statistically significant difference (P < 0.05). Results also showed significantly higher tear strength (newton/millimeter) in Control group followed by Group I and Group II.Conclusion:PVS (heavy body) was found to be most stable, and polyether was seen to be stable of all the impression materials.

Various Disinfecting Methods of Orthodontic Pliers in Daily Clinical Practice: A comparative Study

Introduction: Orthodontic pliers are essential armamentarium in every orthodontic office and should be used&#x0D; once for one patient, then autoclaved before next use. Clinical orthodontics with higher volume of patients,&#x0D; requires a quick chair side disinfection method for pliers, also in rural centres with minimum infrastructure&#x0D; it is a challenge to maintain sterilisation protocols. Various disinfecting agents include alcohols , quaternary&#x0D; ammonium salts, formaldehyde, chloramine, sodium hypochlorite, spirit, glutaraldehyde etc. are available.&#x0D; Out of these we compared the commonly available disinfectants including ethyl alcohol, 5% glutaraldehyde,&#x0D; and 6% sodium hypochlorite to assess their disinfection efficacy after clinical use.&#x0D; Materials and method: 20 orthodontic pliers were inoculated with Coagulase negative streptococci. The&#x0D; pliers were divided in 4 groups with 5 pliers in each group. Each group was subjected to different disinfectant&#x0D; solution with one group aiding as control. The disinfectants used were: spirit (group 1), 5% glutaraldehyde&#x0D; (group 2), 2% sodium hypochlorite (group 3) and distilled water (control group).&#x0D; Results: spirit and 5% glutaraldehyde have shown to be potent disinfectants.&#x0D; Conclusions: Based on these results, we concluded that among the tested methods, disinfection of orthodontic&#x0D; pliers with spirit and 5% glutaraldehyde are the efficient methods for chair-side disinfection.

Curcumin-crosslinked acellular bovine pericardium for the application of calcification inhibition heart valves

Glutaraldehyde (GA) crosslinked bovine or porcine pericardium tissues exhibit high cell toxicity and calcification in the construction of bioprosthetic valves, which accelerate the failure of valve leaflets and motivate the exploration for alternatives. Polyphenols, including curcumin, procyanidin and quercetin, etc, have showed great calcification inhibition potential in crosslinking collagen and elastin scaffolds. Herein, we developed an innovative phenolic fixing technique by using curcumin as the crosslinking reagent for valvular materials. X-ray photoelectron spectroscopy and Fourier transform infrared spectrometry assessments confirmed the hydrogen bond between curcumin and acellular bovine pericardium. Importantly, the calcification inhibition capability of the curcumin-crosslinked bovine pericardium was proved by the dramatically reduced Ca2+ content in the curcumin-fixed group in in vitro assay, a juvenile rat subcutaneous implants model, as well as an osteogenic differentiation model. In addition, the results showed that the curcumin-fixed bovine pericardium exhibited better performance in the areas of mechanical performance, hemocompatibility and cytocompatibility, in comparison with the GA group and the commercialized product. In summary, we demonstrated that curcumin was a feasible crosslinking reagent to fix acellular bovine pericardium, which showed great potential for biomedical applications, particularly in cardiovascular biomaterials with calcification inhibition capacity.

Shallow porous microsphere carriers with core-shell structure based on glass beads cross-linking chitosan for immobilizing inulinase

We develop a new type of shallow porous microsphere carriers with core-shell structure by using glass beads as cores, chitosan as coating layer, glutaraldehyde as cross-linking agent and stearic acid powder as porogen. The characterization of FT-IR, SEM, XRD, TGA-DSC and XPS demonstrates that the modification in each step is feasible and chitosan forms a uniformly coated graft layer on the surface, accounting for 40 % of the total weight. Then, this study focuses on immobilization of inulinase on the shallow porous microsphere carriers. The optimal conditions for immobilization are: pH value is 5.0; cross-linking time is 2.5 h; the molar ratio of free enzyme, glutaraldehyde and carrier amino group is 5.0 × 10−3:0.3:1. Among them, pH value has the most significant influence on the reaction process. The prepared immobilized inulinase preserves 73 % activity of free inulinase, and the suitable ranges of pH and temperature widen. Thermal stability experiments are operated at 70 °C for 3 h, when immobilized inulinase still maintains 69.20 % of initial activities whereas free inulinase only maintains 33.79 %. The immobilized inulinase still maintains 77.93 % of initial activities after 10 reuses, and its calculated half-life is 22 times, demonstrating developmental potential in industrial application.

Comparison of disinfection effects of three disinfectants on gastroscope: a meta analysis

Objective To evaluate the disinfect effects of glutaraldehyde, ortho-phthalaldehyde (OPA) and peracetic acid on gastroscopy disinfection. Methods Relevant literature from PubMed, Cochrane Library, web of science, Embase, CNKI, CBM, VIP were retrieved to collect the randomized controlled trials on disinfection by glutaraldehyde, OPA and peracetic acid on gastroscope. Literature was selected according to the inclusion and exclusion criteria. The RevMan 5.3.4.0 statistic software was used to extract data and a meta-analysis was performed. Results A total of 18 RCT were included. There were significant differences in the disinfect effects between the OPA group and the glutaraldehyde group (OR=2.02, 95%CI: 1.88-1.27, P<0.000 01), and between the peracetic acid group and the glutaraldehyde group (OR=2.79, 95%CI: 1.52-5.11, P=0.000 9). There were no significant differences in the disinfection effect between the OPA group and peracetic acid group (OR=1.30, 95%CI: 0.62-2.73, P=0.49). Conclusion The disinfect effects of OPA and peracetic acid are similar, which are superior to glutaraldehyde. Compared with OPA and glutaraldehyde, peracetic acid is a better choice considering its good disinfect effect and low cost. Key words: Gastroscopes; Disinfection; Glutaraldehyde; Ortho-phthalaldehyde; Peracetic acid

Characterization of Chitosan-Gelatin Blend Scaffolds

Vacuum freeze-drying was used to prepare chitosan-gelatin (CG) scaffolds from hydrogels, with glutaraldehyde (GA) used as a crosslinker. The effects of the changes in volume ratios of the 2 wt% CG and GA solutions on scaffold performance were studied. The ratio of chitosan to gelatin solution volumes, vr(C/G), was adjusted to 1/2 or 1/1, with the 0.25 wt% GA volume at 3, 6, or 8% of the CG/GA volume. Six groups of CG scaffolds were fabricated and the scaffolds performance compared. After the cells were incubated for 4 days, hematoxylin eosin (HE) staining was used to observe the spreading of human skin keratinocyte (HaCaT) cells on these scaffolds, with the MTT method also used to detect the cells proliferation. The inhibition zone method was used on cells cultures to determine the antibacterial properties of the scaffolds against S. aureus and E. coli. Scaffolds were also examined for degradation in lysozyme and their compression properties were tested after degradation. The results showed that the HaCaT cells grew well on these scaffolds and proliferated significantly, indicating that these scaffolds possessed good cytocompatibility. With increased chitosan volume, the antibacterial properties of the scaffolds against S. aureus increased, however, there was no significant change in the antibacterial properties toward E. coli. Increased volumes of chitosan and GA decreased the scaffolds degradation rates and improved the elastic compressive moduli of the scaffolds after degradation. The scaffolds in the vr(C/G) = 1/1, 8% GA group have potential application prospects in the field of skin regeneration.

Comparative evaluation of the effect of electrolyzed oxidizing water on surface detail reproduction, dimensional stability and Surface texture of poly vinyl siloxane impressions.

Aim:The aim of this in vitro study was to comparatively evaluate the effect of chemical disinfectants on the surface detail reproduction, dimensional stability and surface texture of polyvinyl siloxane (PVS) impressions.Materials and Methods:The impressions were then divided into five groups (fifteen samples per group) and subjected to a ten minutes immersion with 2% glutaraldehyde (Group I), 1% sodium hypochlorite (Group II), freshly prepared electrolyzed oxidizing water (EOW) with different pH values - acidic (Group III), alkali (Group IV) and neutral (Group V). The samples were examined pre and post-immersion under visual observation for surface detail reproduction, travelling microscope for measurement of dimensional stability and surface profilometer (3D) for evaluation of surface texture. A standardized master die was fabricated and seventy-five PVS test samples were made. The samples were subjected to immersion disinfection and studied for surface detail reproduction, dimensional stability and surface texture. Post-hoc test, paired t test and ANOVA were used to analyze dimensional stability statistically both within and between the test groups.Results:The surface detail reproduction was satisfactory with both pre and post-immersion test samples. A statistically significant dimensional change was observed post-immersion in Groups II, III and V test samples and a statistically insignificant dimensional change was observed in Groups I and IV test samples. There was a negligible change in surface texture post-immersion in Groups I, III, IV and V test samples with a slight increase in surface roughness post-immersion in Group II samples.Conclusion:In this study, all the test disinfectants produced satisfactory surface detail reproduction on Polyvinyl siloxane impressions. 2% glutaraldehyde and electrolyzed oxidizing water (alkali) have resulted in statistically insignificant dimensional change, while 1% sodium hypochlorite, electrolyzed oxidizing water (acidic) and electrolyzed oxidizing water (neutral) have resulted in statistically significant dimensional changes. All the test disinfectants except 1% sodium hypochlorite showed a reduction in surface roughness (Ra) values.

Effect of Titanium Implants Coated with Radiation-Crosslinked Collagen on Stability and Osseointegration in Rat Tibia.

This study aimed to evaluate the titanium (Ti) implants coated with collagen type I crosslinked using gamma-irrigation or glutaraldehyde (GA). The in vitro surface observations, quantification assay, and cell studies using human mesenchymal stem cells (hMSCs) were conducted. For in vivo experiments, the implants were divided into three groups and inserted into the rat tibias: control group (non-treated Ti implant), GA group (Ti implants coated with GA-crosslinked collagen) and 25 kGy group (Ti implants coated with gamma-radiation-crosslinked collagen at dose of 25 kGy). The animals were sacrificed at 4 weeks after implantation and the tissue sections were obtained. New bone volume (mm3) and bone-to-implant contact (BIC, %) within the region of interest (ROI) was measured. The in vitro results showed the highest osteogenic differentiation and levels of osteogenesis-related gene expressions in the 25 kGy group without cytotoxicity. The new bone volume of GA group was significantly higher than the control (p < 0.05). In the result of the BIC, the 25 kGy group was significantly higher than the control (p < 0.05). However, there was no significant difference between the experimental groups. Within the limitations of this study, Ti implant coated with gamma-radiation-crosslinked collagen has potential utility without side effects from chemical agents.

Comparative evaluation of a low-level laser and topical desensitizing agent for treating dentinal hypersensitivity: A randomized controlled trial.

Aim:The aim of this randomized, controlled, double-blinded, clinical study is to evaluate and compare the clinical effectiveness of low-level diode GaAlAs laser and glutaraldehyde-based topical desensitizing agent on cervical dentin hypersensitivity with the help of visual analog scale (VAS).Materials and Methods:Fifty teeth of patients aged between 20 and 50 years were included, and VAS was used to assess the dentin hypersensitivity. The teeth were randomly allocated to either Group 1 or 2 using flip coin technique. Group 1 received glutaraldehyde desensitizer and Group 2 received 905 nm low-level laser. The sensitivity scores were recorded, immediately, after1 week and 3 months after therapy. Data was analyzed using Mann-Whitney U test for intergroup comparison and Friedman's test for intragroup comparison.Results:There was a significant reduction in pain in both the groups at 3 months evaluation (P = 0.001).However, Group 2 showed a significant decrease in mean VAS scores when compared with Group 1 at both the one week and three month follow ups (P = 0.04, P = 0.03, respectively).Conclusion:Although topical desensitizer and Low Level Laser are both effective in reducing dentinal hypersensitivity, Low Level Lasers are comparatively more effective at the studied time intervals.

New Heterofunctional Supports Based on Glutaraldehyde-Activation: A Tool for Enzyme Immobilization at Neutral pH.

Immobilization is an exciting alternative to improve the stability of enzymatic processes. However, part of the applied covalent strategies for immobilization uses specific conditions, generally alkaline pH, where some enzymes are not stable. Here, a new generation of heterofunctional supports with application at neutral pH conditions was proposed. New supports were developed with different bifunctional groups (i.e., hydrophobic or carboxylic/metal) capable of adsorbing biocatalysts at different regions (hydrophobic or histidine richest place), together with a glutaraldehyde group that promotes an irreversible immobilization at neutral conditions. To verify these supports, a multi-protein model system (E. coli extract) and four enzymes (Candida rugosa lipase, metagenomic lipase, β-galactosidase and β-glucosidase) were used. The immobilization mechanism was tested and indicated that moderate ionic strength should be applied to avoid possible unspecific adsorption. The use of different supports allowed the immobilization of most of the proteins contained in a crude protein extract. In addition, different supports yielded catalysts of the tested enzymes with different catalytic properties. At neutral pH, the new supports were able to adsorb and covalently immobilize the four enzymes tested with different recovered activity values. Notably, the use of these supports proved to be an efficient alternative tool for enzyme immobilization at neutral pH.

Comparison of efficacy and cost-effectiveness of 0.55% ortho-phthalaldehyde and 2% glutaraldehyde for disinfection of laryngoscopes: A prospective pilot study.

Background and Aims:The laryngoscope is a potential source of cross-infection as it involves contact with the mucous membrane, saliva and occasionally blood. This study compared efficacy and cost-effectiveness of two Centre for Disease Control approved agents for disinfection of laryngoscope blades.Methods:One hundred and sixty patients requiring laryngoscopy and intubation for general anaesthesia were randomly allocated into two groups. After tracheal intubation, used laryngoscope blades were cleaned with tap water. The blades were then immersed in either 2% w/v glutaraldehyde for a contact time of 20 min or 0.55% w/v ortho-phthalaldehyde (OPA) for 10 min. The handles were wiped with 0.5% w/v chlorhexidine wipes. Samples were collected using sterile cotton swabs from the tip, flange and light bulb area of the laryngoscope blade and one from the handle. They were cultured aerobically on blood and McConkey agar.Results:In 2% glutaraldehyde group, of 240 samples sent from the blades, 2 (0.8%) showed the growth of methicillin-resistant coagulase-negative staphylococci (MRCONS) and Enterobacter. In OPA group, of 240 samples, 2 (0.8%) showed growth of MRCONS. Thus, 2% glutaraldehyde and 0.55% OPA were comparable in terms of efficacy of disinfection. Growth was seen on 4 out of 160 handles.Conclusions:We suggest OPA for high-level disinfection of laryngoscope blades as it is equally efficacious as compared to glutaraldehyde, with a shorter contact time and available as a ready to use formulation.

Evaluation of Contamination Reduction on Gypsum Casts from Alginate Impressions Disinfected with Four Different Materials

&lt;p&gt;&lt;strong&gt;INTRODUCTION:&lt;/strong&gt; Infection control is one of the most important aspects in dentistry. According to the special features of dentistry, this profession can have a very important role in transmission of infection. This study was conducted by comparing the effects of four common disinfectants on the microbial contamination of alginate impressions and corresponding gypsum casts.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;METHODS &amp;amp; MATERIAL:&lt;/strong&gt; In this experimental study, eleven patients aged 20-30 years old were selected by convenience sampling method. Six alginate impressions for each patient were formed by 24-hour intervals. These sixty six alginate impressions were divided in six groups (control-no wash, wash with water, Micro10, 2% Glutaraldehyde, 5.25% Sodium hypochlorite and Deconex). Disinfection methods were done by spraying (except for glutaraldehyde group that was done by immersing method) and then the alginate impressions were placed in plastic bags for 10 minutes to prevent the evaporation of disinfectants. Sixty six gypsum casts were made from alginate impressions. Microbial swabs were collected from mid palatal region of alginate impressions and gypsum casts for all groups by dried sterile cotton. The swabs were cultured for bacteria by inoculation on Blood Agar at 37°C for 3 days. The positive cultures were counted and the data was analyzed by software SPSS21.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;RESULTS:&lt;/strong&gt; The counting colonies of gypsum casts and alginate impressions which were disinfected by Micro10, 2% Glutaraldehyde, 5.25% Sodium hypochlorite and Deconex were not statistically significant and meaningful.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;CONCLUSION:&lt;/strong&gt; All disinfectants used in this study, had the same and acceptable effect.&lt;/p&gt;