In vitro study of the effect of sodium hypochlorite and glutaraldehyde on substrate adherence capacity of macrophages

The purpose of this study was to investigate the in vitro effect of two irrigation solutions used in endodontics (5.25% sodium hypochlorite and 1% glutaraldehyde) on substrate adherence capacity of macrophages to determine if these substances can alter macrophage function. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Substrate adherence capacity assays were carried out in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index was calculated. Results showed that both sodium hypochlorite and glutaraldehyde significantly decreased the substrate adherence capacity of inflammatory macrophages. To take into account that adhesion is the first step in the phagocytic process of macrophages and in antigen presentation, sodium hypochlorite and glutaraldehyde could inhibit macrophage function and reduce inflammatory reactions in periapical tissues when they are used in root-canal therapy.     

Anaerobic tissue-dissolving abilities of calcium hydroxide and sodium hypochlorite

Closed root canals likely have an oxygen-free environment; most bacteria in canals are anaerobic. These bacteria and other debris are difficult to remove. Unknown is tissue dissolution with chemicals under these anaerobic conditions. This study evaluated and compared dissolving properties of calcium hydroxide (Ca(OH)2) and sodium hypochlorite (NaOCl) on bovine pulp tissue in aerobic and anaerobic environments. Sixty bovine pulp specimens were dried, then randomly divided into six groups. Groups A and B were immersed in Ca(OH)2 + water solution, whereas group C and D were in 2.5% NaOCl. Groups E and F (controls) specimens were placed in distilled water. Groups A, C, and E were incubated anaerobically, and groups B, D, and F were incubated under regular atmospheric conditions, all for 7 days. Percentages of weight loss were compared between groups. Results showed the following: (a) both chemicals partially dissolved pulp tissue, (b) anaerobic environment did not alter tissue-dissolving properties of Ca(OH)2 or NaOCl, and (c) Ca(OH)2 and NaOCl were equal and more effective than water.     

Changes in hemodynamics at different stages of laparoscopic cholecystectomy

The action of indirect electrochemical blood oxidation with 0.06% solution of sodium hypochlorite on kidney and urinary inflammation was studied in experiments on 60 non-inbred rat females of 200-250 g body weight. The animals were intravesically infected through the catheter with E. coli and Ps. aeruginosa. 3 days later, after histological verification of acute pyelonephritis, ureteritis, cystitis, the animals were injected intraperitoneally 1.0 and 2.0 ml daily of sodium hypochlorite solution (control animals) or 0.89% solution of sodium chloride. Though no reliable decrease of the bacterial contamination was achieved, histologically, there was a marked reduction in morphological signs of the inflammation in the kidneys, ureter and urinary bladder on the first day after beginning of electrochemical blood oxidation with solution of sodium hypochlorite in experimental groups. In experimental group rats morphological signs of urinary and renal inflammation for both infections disappeared on days 7 and 10, respectively. In the control animals morphological signs of the inflammation remained after 10 days. Moreover, purulent inflammation was registered in the controls infected with Ps. aeruginosa.     

Inactivation of respiratory syncytial virus by detergents and disinfectants

The activity of a number of detergents and disinfectants against respiratory syncytial virus (RSV) was evaluated in an in vitro assay system. Equal volumes of RSV and serial 10-fold dilutions of the test agents were mixed at 4 degrees C for 5 minutes. The RSV titer in each mixture was compared with that of untreated RSV alone. In 14 experiments with input RSV titers ranging from 2.6 x 10(3) to 2 x 10(7) plaque-forming units/ml, a 10-fold dilution of 5.25% sodium hypochlorite (generic bleach) inactivated (> or = 3-log reduction in titer) the virus. With lower RSV titers inactivation was also observed at a 100-fold dilution of bleach. Fetal calf serum concentrations up to 50% as an organic load did not diminish the bleach effect. The degree of RSV inactivation was also defined for Lysol, povidone-iodine, Amphyl, Hibiclens, Osyl, ethanol and Listermint. The short contact time, the reproducible nature of the findings and the continued effectiveness with increasing organic loads all suggest that detergents and disinfectants can potentially play an important role in decreasing the spread of RSV infection.     

Efficacy and mechanisms of action of sodium hypochlorite on Pseudomonas aeruginosa PAO1 phage F116

The Pseudomonas aeruginosa PAO1 phage F116 was used to investigate the viricidal activity and the mechanism of action of sodium hypochlorite. The bacteriophage was inactivated with a low concentration (0.0005% available chlorine) of the biocide prepared in tap water but it was less sensitive to a sodium hypochlorite solution prepared in ultra-pure water (0.0075% available chlorine). For all the effective concentrations of sodium hypochlorite (i.e. producing at least 4 log reduction in phage titre), F116 was readily inactivated within 30 s. Electron microscopical investigations of the phage particles challenged with sodium hypochlorite showed a wide variety of deleterious effects, some of which have not been previously observed with other biocides. The wide range of structural alterations observed suggested that sodium hypochlorite has multiple target sites against F116 bacteriophage. A 30 s exposure to sodium hypochlorite (0.001% available chlorine) produced severe damage, the number and severity of which increased with a higher concentration (0.0075% available chlorine) and with a longer contact time. These observations suggested that sodium hypochlorite inactivated F116 bacteriophage by causing structural alterations to the phage head, tail and overall structure, hence possibly releasing the viral genome from damaged capsids in the surrounding media.     

Stability of vinblastine sulphate in 0.9% sodium chloride in polypropylene syringes

The stability of vinblastine sulphate diluted in 0.9% sodium chloride solution for injection was studied. Vinblastine sulphate was reconstituted with 0.9% sodium chloride solution for injection to concentration of 1.0 mg/mL and stored in polypropylene syringes at 25 degrees C +/- 1 degree C protected from light. On different days the solutions were analysed and the vinblastine concentration was determined by high-performance liquid chromatography. An high-pressure liquid chromatographic method is described for the quantitative determination of vinblastine in the presence of its degradation products. The degradation of vinblastine was studied by examining the percentage changes from the theoretical concentrations for each solution. The results of these studies indicate that vinblastine solutions in 0.9% sodium chloride solution for injection (1 mg/mL) in polypropylene syringes at 25 degrees C +/- 1 degree C protected from light are stable for up to one month.     

Stability of ondansetron hydrochloride and 12 medications in plastic syringes

The stability and compatibility of ondansetron hydrochloride with neostigmine methylsulfate, naloxone hydrochloride, midazolam hydrochloride, fentanyl citrate, alfentanil hydrochloride, atropine sulfate, morphine sulfate, meperidine hydrochloride, propofol, droperidol, metoclopramide monohydrochloride, and glycopyrrolate were studied. Ondansetron 1.33 or 1.0 mg/mL was combined with 0.9% sodium chloride injection and each of the 12 drugs in duplicate in plastic syringes (or glass for propofol). The syringes were stored at 21.8-23.4 or 4 degrees C in the dark, except for those containing propofol, which were stored at ambient temperature. Samples were removed at 0, 4, 8, and 24 hours for analysis by high-performance liquid chromatography and pH measurement; the propofol-containing samples were removed at 0, 1, 2, and 4 hours. Syringes were visually assessed for color and clarity, and particulate content was measured with a particle counter at the end of the study period. All solutions containing ondansetron retained more than 90% of their initial ondansetron concentration. Solutions containing each of the other drugs except droperidol retained more than 90% of their initial concentration of these drugs. The solutions containing droperidol retained more than 90% of their initial droperidol concentration for up to eight hours at ambient temperature but precipitated quickly at 4 degrees C. In combinations of ondansetron 1.33 or 1.0 mg/mL and 10 of 12 drugs, all drugs were stable for 24 hours in plastic syringes at 23 and 4 degrees C; ondansetron hydrochloride 1.0 mg/mL and propofol 1.0 and 5.0 mg/mL in admixtures were stable for 4 hours, and droperidol on its own and combined with ondansetron 1.0 mg/mL was stable for no more than 8 hours at ambient temperature.     

Effectiveness of two methods of denture sterilization

Species of Candida and in particular Candida albicans may be involved in the aetiology of denture stomatitis. Studies have shown that Candida and other oral micro-organisms including Streptococcus gordonii are associated with denture plaque; hence denture hygiene is an important factor in the prevention and treatment of the disease. The aim of this investigation was to test in vitro the efficacy of two methods of denture sterilization: (1) microwave irradiation and (2) sodium hypochlorite soak. Twenty upper acrylic dentures were prepared for microbiological assay; 10 were inoculated with C. albicans H1 and 10 with S. gordonii LGR2. Within each group, five dentures were tested in a domestic microwave oven for optimal exposure time and temperature to ensure sterilization; the five control dentures were not microwaved. Microbiological analyses showed that the inoculated dentures became sterile after six min of irradiation at medium setting (2450 MHz, 350 W). Damage to the microorganisms after microwave irradiation was clearly visible by scanning electron microscopy (SEM). Following the same protocol as above, experimental dentures were soaked for 8 h in either 0.02%, or 0.0125% sodium hypochlorite solution and control dentures soaked in distilled water. Microbiological analyses showed that the experimental dentures inoculated with C. albicans H1 became sterile. By contrast, those inoculated with S. gordonii LGR2 did not become sterile, and the SEM procedures confirmed these findings. The results of this study indicate that microwaving may be a more effective method of denture sterilization than denture soaking in sodium hypochlorite. However, compared with microwaving, hypochlorite reduces the levels of residual non-viable micro-organisms attached to the denture surface.     

从难处理金精矿氯化浸金溶液中吸附金

对国内某难处理金精矿高压氧化渣进行氯化浸出及吸附试验。结果表明,在下述最佳条件下浸金率达到96.5%:次氯酸钠浓度10g/L、pH=4、氯化钠浓度75g/L、温度40℃、液固比3∶1、搅拌速度300r/min、时间120min。浸金液在室温采用1g/L的717阴离子交换树脂吸附30min,金吸附率达到99.2%。该方法污染少、操作简单、反应速度快。     

某难浸金矿的次氯酸钠浸出研究

采用次氯酸钠对贵州某难浸金矿进行浸出,考察次氯酸钠浓度,浸出时间和温度对金浸出率的影响。结果表明,次氯酸钠不仅可氧化分解矿石中的FeAsS和FeS2,同时还可以打开包裹的金;在下述优化条件下,金浸出率可达到75%以上:次氯酸钠质量浓度0.6mol/L,pH 13～14,液固比6,35℃浸出4h。     

钴电积氯气回收副产次氯酸钠系统的优化改造

在氯化钴密闭电解生产实践中,针对氯气吸收副产次氯酸钠运行存在的问题进行工艺研究、设备优化、增加自动控制系统。通过进气温度、吸收温度、吸收液余碱浓度对氯气吸收的影响试验,确定了氯气吸收控制条件及吸收终点的pH与氧化还原电位和电导率的关系;吸收系统增加了吸收系统温度自动控制,吸收终点的pH、氧化还原电位、电导率联合控制系统,有效提高了氯气吸收系统的运行稳定性,保证了次氯酸钠的产品品质。改造后氯气吸收系统运行稳定,次氯酸钠产品质量得到明显提高,有效氯12%~14%、余碱0.6%~1.0%,每吨钴的液碱(32%)消耗降低了260kg,有效降低了生产的成本,提高了企业的经济效益和市场竞争力。     

金精矿无污染提金新技术的研究

采用次氯酸钠从烟台地区金精矿中提取金银，金银浸出率分别达９８％和５４％，浸取周期仅为常规氰化法的１／３。对主要影响因素包括次氯酸钠浓度、浸取时间、浸取温度进行了考察。     

Resistance of Pseudomonas aeruginosa PAO1 phage F116 to sodium hypochlorite

The development of viral resistance to sodium hypochlorite was investigated using the Pseudomonas aeruginosa bacteriophage F116 as a model system. This phage was chosen because of its structural characteristics and former investigations conducted in this laboratory. F116 was shown to be sensitive to a sodium hypochlorite concentration of 0.0075 gl-1 (available chlorine) which produced a 5 log10 reduction in titre in a suspension test. Survival bacteriophages challenged with this sodium hypochlorite concentration were isolated, propagated and challenged again with the same and higher concentrations of the biocide. It was observed that progeny virions were becoming increasingly resistant to sodium hypochlorite challenges up to a concentration of 0.0175 gl-1 of available chlorine. It was also noticed that 1-2 log10 of F116 virions from resistant phage lysates remained sensitive to the biocide. An electron microscopical investigation of F116 resistant lysates showed that the phage resistance to sodium hypochlorite was not caused by F116 particles aggregation. Furthermore, no morphological difference between the sensitive and resistant F116 particles to sodium hypochlorite was identified.     

液氯化法浸出硫化金精矿压热氧化渣的电位变化研究

根据氯化物体系中金的浸出热力学,预测合理的电位和pH值范围。通过对硫化金精矿压热预处理后的氧化渣进行液氯化浸出试验,考察了浸出过程中电位变化与浸金率之间的关系。氯化浸出金适宜的热力学条件为pH值8以下、电位0.9 V以上。从次氯酸钠溶液的氧化能力角度考虑,pH值在4～5.5时其氧化能力较强,此时溶液中氧化剂以HClO为主。对金精矿压热氧化渣的次氯酸钠浸出,为得到较高的浸金率,必须控制至少2 h电位在1.0 V以上。若在浸出过程中电位低于1.0 V,已溶解生成的金氯络合物会再沉淀,使浸金率下降。在初始有效氯质量分数为0.5%、初始pH值为4.0时,可保证2 h内电位在1.0 V以上,此时浸金率可达到96%以上。     

Leaching of Chalcopyrite with Sodium Hypochlorite

A laboratory study was conducted on the leaching of chalcopyrite with NaOCl (sodium hypochlorite). Experiments were carried out in the following two stages: (1) Chalcopyrite was converted to CuO (cupric oxide) with a sodium hypochlorite solution, and (2) cupric oxide was dissolved to cupric ions with 1 normal sulfuric acid at room temperature. In the first-stage leaching, the initial pH varied from 12.5 to 13.7, the temperature from 35 °C to 75 °C, the sodium hypochlorite concentration from 0.2 to 0.85 molar, and the chalcopyrite dosage from 1 to 10 g/500 ml. The leaching conversion showed a maximum (68.3 pct) around a pH of 13.2 at 0.5 molar OCl^– (hypochlorite) concentration and at 65 °C in 1 hour. The reagent consumption ratio—defined as the number of moles of hypochlorite consumed to leach 1 mole of chalcopyrite—was much higher than its stoichiometric ratio of 8.5. It reached 57.6 when the solid dosage was 1 g/500 ml and decreased to 12.9 when the solid dosage was increased to 10 g/500 ml. The leaching rate of chalcopyrite in the first stage was controlled by a chemical reaction with the activation energy of 50.2 kJ/mol (12.0 kcal/mol). A leaching scheme was identified in which 98 pct of the chalcopyrite was leached by adding hypochlorite stock solution stepwise in less than 3 hours.     

Chemical ablation of the gallbladder: evaluation of multiple agents in vitro

PURPOSE: To find a more effective chemical regimen for transcatheter ablation of the gallbladder in an in vitro model. MATERIALS AND METHODS: Sectioned and whole pig gallbladders were exposed in vitro to 12 different chemical solutions at varying conditions of exposure time, pH, and temperature. RESULTS: In the in vitro studies, 0.1 N and 1.0 N solutions of sodium hydroxide in water or ethanol and 3% hydrogen peroxide were the most effective sclerosant agents. Ethanol and hydrochloric acid failed to completely eliminate the epithelium from the gallbladder sections. Increasing exposure time from 10 to 20 minutes or increasing the temperature of the solutions from 37 degrees C to 50 degrees C did not alter these results. Sequential 15-minute exposures to 0.1 N sodium hydroxide in ethanol followed by peroxide completely eliminated the epithelium from whole gallbladders in vitro. CONCLUSION: Alkaline solutions and hydrogen peroxide are more effective than ethanol alone, acids, or detergents in eliminating gallbladder epithelium in this model. Further evaluation of these agents in vivo is merited.     

A scanning electron microscopic study of the cleansing effectiveness of three irrigating modalities on the tubular structure of dentin

This is a scanning electron microscope study of the cleaning effectiveness of three irrigating modalities on root dentin. When hydrogen peroxide was followed by sodium hypochlorite, it effectively cleaned the dentinal tubules of the root. When RC-Prep was reacted with sodium hypochlorite, it proved to be a more efficient irrigating method than the hydrogen peroxide and sodium hypochlorite solution. When a new improved RC-Prep with 15% carbanide peroxide was reacted with sodium hypochlorite, it proved to be a superior cleansing method for root dentin.     

次氯酸钠高碱高盐氧化分解贵州某难处理金矿载金硫化矿的研究

在我国南方广泛发育着产在富亩有机质的海相细粒碳酸盐型沉积碎屑岩系的碳质难处理金矿在这类金矿中金以微细粒自然金赋存在黄铁矿等载金矿物中,常规氰化难以浸出,浸出率大约为10% 。去除载金硫化矿物的包裹干扰是实现金浸出的有力措施．次氯酸钠作为一种强氧化剂特别适台碳酸盐岩矿浆舟质中氧化分解硫化矿去除金浸出的包裹干扰。黄铁矿的氧化分解受有效氯浓度、氯化钠浓度、液固比及pH等多种因素的干扰,经次氯酸钠氧化分解后,金的包裹干扰已基本消除,金的浸出率可达85%     

Intraocular pressure-raising potential of 1.0% rimexolone in patients responding to corticosteroids

OBJECTIVE: To compare the intraocular pressure (IOP) elevating potential of 1.0% rimexolone and 0.1% fluorometholone alcohol ophthalmic suspensions in patients known to have responded to corticosteroids. DESIGN: In a double-masked, randomized, single-eye, crossover protocol, corticosteroid responsiveness initially was verified in 40 asymptomatic known steroid responders by challenge with either 0.1% dexamethasone sodium phosphate or 1.0% prednisolone acetate for up to 6 weeks. After a 1-month medication washout, subjects randomly received either rimexolone or fluorometholone for 6 weeks. Medications were again discontinued for 1 month, and subjects then received the alternate drug for 6 weeks. RESULTS: There was no significant difference between rimexolone and fluorometholone in the number of subjects demonstrating a 10-mm Hg increase in IOP or in the mean number of weeks required to achieve a 10-mm Hg response. Responses occurred in significantly more subjects receiving dexamethasone sodium phosphate (P = .001) or prednisolone acetate (P < .001) and in a significantly shorter interval than in subjects receiving rimexolone. CONCLUSIONS: Rimexolone has a low IOP-elevating potential, comparable to that of fluorometholone and less than that of dexamethasone sodium phosphate and prednisolone acetate.