Effects of salt and serum on the sporicidal activity of liquid disinfectants

This study compares the effects of various concentrations of salt or serum in the killing of Bacillus subtilis spores by either glutaraldehyde, sodium hypochlorite, cupric ascorbate, hydrogen peroxide, peracetic acid, formaldehyde, or phenol. Salt affected only glutaraldehyde, its sporicidal activity increasing with an increase in concentration of sodium bicarbonate or sodium chloride. The sporicidal activity of glutaraldehyde was minimal when the concentrations of aldehyde groups and lysine residues from protein were similar. We present an equation describing the effect of serum on spore survival as a function of glutaraldehyde concentration that fits the data with a regression coefficient of 0.9. Cupric ascorbate and peracetic acid were inhibited by serum, but this effect was linked to a rise in pH. Sodium hypochlorite was the agent most sensitive to protein, with its sporicidal activity nearly disappearing in the presence of 2% serum or an equivalent amount of purified protein.     

Sporicidal activities of disinfectants on Paenibacillus larvae

Sporicidal activities of glutaraldehyde, sodium hypochlorite, povidone iodine, ethylene oxide gas, chlorhexidine gluconate, and didecyl dimethylammonium chloride on wet and dry spores of Paenibacillus larvae (basonym: Bacillus larvae) were evaluated for control of honeybee American foulbrood. Glutaraldehyde was found to have a strong and rapid effect on both the wet and the dry spores among the disinfectants tested.     

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.     

Chemical modification of amino acid residues in glycerinated Vorticella stalk and Ca(2+)-induced contractility

The effects of sodium dichloroisocyanurate (NaDCC) and Solprogel (Laboratorios Inibsa, S.A., Barcelona, Spain), a compound that contains NaDCC plus a biodegradable polymer of acrylic acid, on the activity of DNA polymerase (DNA-P) associated with hepatitis B virus in serum were evaluated. DNA-P positive and negative pools of human serum samples were used as positive and negative stock virus. Inhibition of DNA-P activity by NaDCC and the commercial product was found to be concentration-dependent. Two minutes exposure to the minimum effective concentration of NaDCC (1000 ppm available chlorine) or Solprogel 16% (960 ppm available chlorine) totally inhibited DNA-P activity.     

Relationship between the ultrastructure and biochemical composition of spores and their resistance to high temperature exposure and chemical agents

The author used the spores of B. cereus and of its two mutants (10id -- defective by spore coats, and No. 3 -- DPA-deficient). The mentioned microbes were subjected to the action of vapour (99 degrees), 5% sodium hydroxide solution at a temperature of 50 degreeC, and of 0.25% sodium hypochlorite solution. On the basis of the survival curves it was revealed that a mutant with defective coats possessed the least resistance to the factors under study. On these grounds a conclusion was drawn on the important portective function of the spore coat, and not simply of the presence of DPA, in the mechanism of thermo- and chemical resistance of spores.     

Apoptosis in cancer

The antiviral activities of sodium dichloroisocyanurate (NaDCC) and a commercial product (Solprogel 2%) against human immunodeficiency virus type 1 (HIV-1) were investigated using a quantitative suspension test method. Solprogel is a compound that contains NaDCC and a biodegradable polymer of acrylic acid. Viral suspensions were prepared containing 3.2 x 10(6) tissue culture infective dose 50 (TCID50) in culture media. Syncytium formation in the MT-2 line and HIV antigen p24 on the supernatant of the cultures were used to determine viral titre. Results indicate that satisfactory disinfection (1000-fold reduction in 5 min) can be achieved using NaDCC and Solprogel at concentrations of 100 and 120 ppm available chlorine, respectively.     

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。     

A practical approach to suspicious death in infancy--a personal view

Five commercially available liquid glutaraldehyde preparations (Glutaron II, Cidex 28, Glutalabor, Banicide, and Anti-G-Plus) were compared for effectiveness in sterilizing gutta-percha cones artificially contaminated with Bacillus subtilis ATCC 6633 spores. Sporicidal activity differed for the various brands of cones, but after 15 min all glutaraldehyde solutions were effective in eliminating the spores. However, three solutions (Cidex 28, Banicide, and Anti-G-Plus) showed sporicidal activity within a shorter time (10 min). All glutaraldehyde solutions tested may be used in endodontic practice for rapid decontamination of gutta-percha cones, thus contributing to the maintenance of the aseptic chain, an essential factor for successful root canal treatment.     

The Chinese total diet study in 1990. Part II. Nutrients

This paper reports the intakes of 72 nutrients and their dietary sources obtained from the Chinese total diet study in 1990. Most of the nutrient intakes are close or equal to their corresponding recommended daily allowances (RDAs). Both the total energy intake (2203 kcal) and the proportions contributed by protein, fat, and carbohydrate meet the current Chinese RDAs and the World Health Organization (WHO) nutrient goals. The average protein intake was 64 g/day. The intake of essential amino acids all exceeded the Chinese RDA, and their proportions were generally consistent with the WHO recommended pattern. The average fat intake was 51.2 g/day (21.2% of the total energy intake). However, the dietary fat intake has been increasing significantly in the Chinese diet and the proportion of animal fat has reached 53% of the total fat intake. The total saturated:total monounsaturated: total polyunsaturated fatty acid ratio was 1.0:1.5:1.0. Although the average cholesterol intake was only 179 mg/day, it was 248 mg/day in the South 1 region. The intakes of thiamine and riboflavin were below the RDA. Retinol intakes in all the 4 regions were low. Most (80%) of the retinol (equivalent) intakes were from carotenoids. The average intake of total tocopherol was 89% of the RDA, and among the 4 regions, only the South 2 region has relatively low intake. The intakes of iron, copper, manganese, sodium, and phosphorus were adequate. The intakes of calcium, zinc, and potassium were insufficient, and intakes of selenium and magnesium were a little low. High sodium and low potassium intake is a traditional problem in the Chinese diet.     

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.     

Fatty acids of vegetative cells and spores of Bacillus licheniformis

Lipids were extracted from vegetative cells and spores of Bacillus licheniformis. Vegetative cells were grown in nutrient broth and spores on nutrient agar. Total lipid approximated 2.89% of the dry weight of vegetative cells and 2.09% of the dry weight of spores. The fatty acids were prepared as methyl esters and analyzed by gas chromatography and mass spectrometry. There were six fatty acids in concentrations greater than 5% of the total lipid in both spores and vegetative cells, but only palmitic acid was common to both. Fatty acids from vegetative cells in quantities of 5% or more of the total lipid material were lauric, myristic, palmitic, palmitoleic, and linoleic acids. Fatty acids from spores in concentrations greater than 5% of the total lipid were isopentadecylic, palmitic, Carbon-17 iso, and three other long or branched chain fatty acids which were not identified. Spores contained more long and branched chain fatty acids with odd numbers of carbon atoms than did vegetative cells.     

Reaction of hypochlorous acid with bovine nasal cartilage comparison to pig articular cartilage

The action of sodium hypochlorite (NaOCl) on bovine nasal cartilage was studied by proton nuclear magnetic resonance (1H-NMR) spectroscopy in order to model degradation processes of cartilage caused by neutrophil-derived hypochlorous acid. Nasal cartilage was chosen as a mean of comparison because it differs from articular cartilage in its composition. It contains some more proteoglycans, i.e. polymeric carbohydrates and less collagen than articular cartilage. This is important for studying the influence of hypochlorous acid on cartilage components (collagen and polysaccharides). Cartilage samples were incubated at 37 degrees C with phosphate buffer in the presence or absence of NaOCl. Supernatants were collected and assayed by NMR-spectroscopy. In the presence of pure phosphate buffer, the supernatants of bovine nasal cartilage were less rich in low molecular mass metabolites (e.g. amino acids, lactate) than articular cartilage. However, intense signals for highly mobile N acetyl groups of cartilage polysaccharides were detectable in nasal cartilage. NaOCl caused an increase in signals for acetate and formiate. Signals for N-acetyl groups rose only during the first 25 minutes of incubation with NaOCl. Then, their concentration decreased markedly. These changes were related to an enhanced release of chondroitinsulfate from nasal cartilage.     

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.     

Disinfection of medical and surgical equipment: efficacy of chemical disinfectants and water and soap

In this experimental study we compared the previous descontamination efficacy of the medical surgical materials by the use of chemical disinfectants and the mechanical cleaning with water and soap, as well as verified the organic material interference in these procedures. To carry out this study, we used surgical pincers under contamination with: Staphylococcus aureus ATCC-6538, Salmonella cholerae suis ATCC-10708, and Pseudomonas aeruginosa ATCC-15442 in presence and absence of organic matter (fetal bovine serum). The following treatments: glutaraldehyde 2%, sodium hypochlorite 1%, hydrogen peroxide 6%, alcohol 70% and the mechanical cleaning with water and soap were compared with eight repetitions in a total of 480 observations. In the described conditions, the disinfectants had a good efficacy in the previous descontamination of the medical surgical materials and a less inactivation by the organic material. The mechanical cleaning with water and soap showed a reduction of the microrganism to safe levels, considered adequate for previous descontamination.     

次氯酸钠在宝钢生活水站应用前景研究

通过对次氯酸钠消毒方式的消毒效果、稳定性及经济性、安全性等各方面的论证,分析了宝钢生活水采用次氯酸钠消毒的优劣,认为采用次氯酸钠消毒,使用安全性有了很大提高,且设备成本大幅下降,但是次氯酸钠水溶液易分解,且运行成本较高。     

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.     

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。     

Low-frequency vibrations in the treatment of patients with acute maxillary sinusitis and ethmoiditis. Non-specific resistance and immunity

Effect of sodium hypochlorite disinfection of impressions on the size and quality of plaster models is studied. Twenty-minute submerging of silicone impressions in 0.5% sodium hypochlorite solution did not change their size and did not deteriorate the quality of surface and hardness of plaster models. Stomalgin impressions cannot be disinfected by sodium hypochlorite solution because of expressed destructive effect of this disinfectant on the impressions.     

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.     

Effective shelf-life of prepared sodium hypochlorite solution

Although the tissue solvent and bactericidal properties of sodium hypochlorite are well known, the effective shelf-life of prepared sodium hypochlorite solutions is not known. The stability of sodium hypochlorite is adversely affected by exposure to high temperature, light, air, and the presence of organic and inorganic contaminants. The purpose of this study was to investigate the variables of storage conditions and time on the tissue-dissolving capacity of three different concentrations of sodium hypochlorite. Fresh frozen human umbilical cord was used as the tissue sample for this experiment. Tissue samples were dissolved at time intervals ranging from 1 day to 10 wk in 5.25%, 2.62%, and 1.0% solutions of sodium hypochlorite. The tissue-dissolving ability of 5.25% sodium hypochlorite remains stable for at least 10 wk. The tissue-dissolving ability of 2.62% and 1.0% sodium hypochlorite remains relatively stable for 1 wk after mixing, then exhibits a significant decrease in tissue-dissolving ability at 2 wk and beyond.