Intrathecal edaravone, a free radical scavenger, is effective on inflammatory-induced pain in rats

BACKGROUND

Free radicals have some roles in inflammation and systemic and local tissue injuries. (Free radical scavengers are neuroprotective against excitotoxic insults.) Therefore, we hypothesized that free radical scavenger would be analgesic on pain induced by excitotoxicity or inflammation. The purpose of this study was to investigate analgesic effects of intrathecally administered edaravone, a free radical scavenger, on thermal and inflammatory pain.

METHODS

Sprague-Dawley rats were implanted with lumbar intrathecal catheters. Edaravone 0.05, 0.1, 0.5, and 1 mg per 20 microl or saline 20 microl (control) were administered intrathecally, and the withdrawal response to thermal stimulation to the tail (tail-flick test) or flinch responses to subcutaneous formalin injection into the hind paw (formalin test) were tested. General behaviour and motor function were also examined. In each dose group, eight rats were used.

RESULTS

No dose-dependent analgesic effects were observed in the tail-flick test. However, dose-dependent analgesia was obtained in both phase 1 and 2 of the formalin test. The 50% effective dose values were 0.25 mg (95% confidence interval, 0.11-0.56 mg) in phase 1 and 0.25 mg (95% confidence interval, 0.061-1.05 mg) in phase 2. No behavioural side-effects nor motor dysfunction was observed, even with the maximum soluble dose (1 mg/20 microl).

CONCLUSION

Intrathecally administered edaravone, a free radical scavenger, had analgesic effects on inflammatory-induced acute and facilitated pain but not on acute thermal pain, without any behavioural side-effects.

Preemptive effect of intravenous ketamine in the rat: concordance between pain behavior and spinal fos-like immunoreactivity

BACKGROUND

The purpose of this study was to compare behavioral antinociceptive responses with spinal fos-like immunoreactivity (FLI) for a intravenous ketamine injection between pre vs. postformalin administration in rats.

METHODS

Sprague-Dawley rats (250-300 g) were prepared to receive either saline or ketamine. All rats were randomly divided into three groups: control, pretreatment and post-treatment group. Formalin (5%) 100 microl was injected into the hindpaw. Pain related behavior and FLI in the lumbar spinal cord was examined.

RESULTS

Flinches of phase 2 were 239.3 (22,8), 118.6 (7,5) (P < 0.05 vs. control and post-treatment group), and 186.7 (16,6) in the control, pre and, post-treatment groups, respectively. Fos-like immunoreactivity expression was significantly correlated with phase 2 flinching behavior (P < 0.001).

CONCLUSION

Pretreatment with intravenous ketamine inhibits inflammatory pain behavior and FLI expression following a formalin injection in rats, suggesting that pretreatment of ketamine plays an important role in preemptive analgesia.

Efficacy of an Iodophore Teat Disinfectant Against Staphylococcus aureus and Streptococcus agalactiae in Experimental Challenge

A 1.0% iodophore teat disinfectant (Full-Bac) was evaluated in comparison with a positive control (Bovadine), a commercially available 1.0% iodophore teat disinfectant. The study was conducted under conditions of experimental challenge, following the guidelines recommended by the National Mastitis Council. The test product and a positive control were compared in 41 cows, with 82 teats receiving each product at milking, during a 10-wk study period. There were no differences between the test product and the positive control in new intramammary infections due to Staphylococcus aureus, which averaged 13.4% in each of the 2 treatment groups. Additionally, no statistical difference was seen between the test product and positive control in new intramammary infections by Streptococcus agalactiae, which averaged 8.5 and 6.1% for the Full-Bac and Bovadine groups, respectively. Teat skin and teat end condition scores were statistically evaluated at wk 1, 5, and 9 of the study, and no significant differences were observed between the treatment groups. The test teat disinfectant provided similar germicidal activity to that of the positive control teat disinfectant with no adverse effects on teat skin or teat end condition during the warm-season study period.

[Evaluation in vitro of the antibacterial effectiveness of 2.5% sodium hypochlorite on endocanal bacteria related to the time contact within root canal]

INTRODUCTION

The aim of this study was to evaluate the antibacterial effectiveness of 2.5% sodium hypochlorite on endocanal bacteria related to the time contact Within root canal.

MATERIALS AND METHODS

110 teeth were prepared and inoculated with Enterococcus feacalis. All teeth were irrigated with a same volume and exposed a period ranging 1 to 10 min. Canals were sampled before and after time contact.

RESULTS

All time reduced the number of bacterial cells within the root canal (p > 0.05). There was no significant difference after the time contact of 3 min (p > 0.05). Lack of effectiveness might be caused by irrigant to reach microorganism in dentinal tubules.

Application of antimicrobial ice for reduction of foodborne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes) on the surface of fish

AIMS

The efficacy of antimicrobial ice was evaluated for the reduction of foodborne pathogens on the surface of fish.

METHODS AND RESULTS

Antimicrobial ice containing chlorine dioxide (ClO2) was utilized to control foodborne pathogens in laboratory media and on fish skin. Escherichia coli O157:H7, Salmonella serotype Typhimurium and Listeria monocytogenes strains were treated with antimicrobial ice for 30 min on plates of selective agar and for 120 min on fish skin at room temperature, and then incubated for enumeration. After treatment with 100 ppm ClO2 for 30 min, 5.4, 4.4 and 3.2 log10 reduction was obtained with E. coli O157:H7, Salm. Typhimurium and L. monocytogenes on laboratory media, respectively. When antimicrobial ice (100 ppm ClO2) was applied to fish skin for 120 min, total reduction of E. coli O157:H7, Salm. Typhimurium and L. monocytogenes was 4.8, 2.6 and 3.3 log10, respectively.

CONCLUSION

The initial load of foodborne pathogens was reduced by antimicrobial ice and the lowered microbial level was maintained during treatment.

SIGNIFICANCE AND IMPACT OF THE STUDY

The application of antimicrobial ice is a simple and effective method for the safe preservation of fish.

In Vitro Efficacy of a Polyhexamethylene Biguanide-Impregnated Gauze Dressing Against Bacteria Found in Veterinary Patients

OBJECTIVE

To evaluate the in vitro efficacy of polyhexamethylene biguanide (PHMB)-impregnated gauze dressing in limiting the growth of bacteria both within and underneath the dressing.

STUDY DESIGN

In vitro study.

METHODS

Squares of PHMB-impregnated and control gauze were placed on agar plates inoculated with 1 of 11 bacterial species, including 8 multi-resistant organisms. Growth under the gauze was assessed qualitatively after 24-hour incubation. Repeated use of sponges was used to evaluate residual inhibitory activity against Micrococcus lutea and Staphylococcus schleiferi ss. schleiferi. In a second procedure, PHMB-impregnated and control gauze squares were placed in sterile plastic wells and inoculated with 1 of 5 bacterial species, including Pseudomonas spp. and Klebsiella spp. Inhibition of bacterial growth within and underneath the dressing after 24-hour incubation was evaluated by quantifying the numbers of bacteria on the well floor and within each square.

RESULTS

PHMB-impregnated gauze provided greater inhibition of growth of 4/4 Gram-positive species and 2/6 Gram-negative species on inoculated plates compared with control gauze. Residual inhibitory activity of PHMB-impregnated gauze was significantly greater against M. lutea on all days and against S. schleiferi ss. schleiferi on days 1 and 4 compared with control. No bacteria were recovered from inoculated PHMB-impregnated gauze squares placed in sterile wells or from the well floor underneath. More than 9 x 10(5) colony-forming units (CFU) were recovered from inoculated control samples placed in sterile wells and more than 8.4 x 10(4) CFU were recovered from control well floors.

CONCLUSION

PHMB-impregnated gauze dressing, when placed on inoculated agar plates, reduces growth of underlying bacteria, particularly Gram-positive species. Wet-inoculated PHMB-impregnated dressing prevents growth of Gram-positive and Gram-negative bacteria both within and underneath the dressing.

CLINICAL RELEVANCE

PHMB-impregnated dressings may be useful for reducing contamination of underlying wounds by bacterial pathogens.

Endotracheal Tubes Coated with Antiseptics Decrease Bacterial Colonization of the Ventilator Circuits, Lungs, and Endotracheal Tube

Background

Formation of a bacterial biofilm within the endotracheal tube (ETT) after tracheal intubation is rapid and represents a ready source of lung bacterial colonization. The authors investigated bacterial colonization of the ventilator circuit, the ETT, and the lungs when the ETT was coated with silver-sulfadiazine and chlorhexidine in polyurethane, using no bacterial/viral filter attached to the ETT.

Methods

Sixteen sheep were randomized into two groups. Eight sheep were intubated with a standard ETT (control group), and eight were intubated with a coated ETT (study group). Animals were mechanically ventilated for 24 h. At autopsy, the authors sampled the trachea, bronchi, lobar parenchyma, and ETT for quantitative bacterial cultures. Qualitative bacterial cultures were obtained from the filter, humidifier, inspiratory and expiratory lines, and water trap. ETTs were analyzed with light microscopy, scanning electron microscopy, and laser scanning confocal microscopy.

Results

In the control group, all eight ETTs were heavily colonized (10(5)-10(8) colony-forming units [cfu]/g), forming a thick biofilm. The ventilator circuit was always colonized. Pathogenic bacteria colonized the trachea and the lungs in five of eight sheep (up to 10(9) cfu/g). In the study group, seven of eight ETTs and their ventilator circuits showed no growth, with absence of a biofilm; one ETT and the respective ventilator circuit showed low bacterial growth (10(3)-10(4) cfu/g). The trachea was colonized in three sheep, although lungs and bronchi showed no bacterial growth, except for one bronchus in one sheep.

Conclusions

Coated ETTs induced a nonsignificant reduction of the tracheal colonization, eliminated (seven of eight) or reduced (one of eight) bacterial colonization of the ETT and ventilator circuits, and prevented lung bacterial colonization.

Effects of Applying Safe2 O Poultry Wash to Broiler Wings on Shelf Life, Listeria Monocytogenes, Pseudomonads, Staphylococcus Species, and Psychrotrophic Bacteria Levels After Three, Seven, and Ten Days of Storage

Bacterial contamination of raw processed poultry continues to be of concern to consumers as well as regulatory and health officials. For many years wings were considered a low-value product; therefore, shelf life of wings was not a major concern. Due to changes in consumer attitudes and increases in the fast-food market, wings are now a valuable commodity. Because wings have a shorter shelf life than most other raw poultry products, acceptable intervention to decrease the population of associated spoilage organisms and human enteropathogens are needed. Safe2O Poultry Wash was evaluated as a postchill treatment to reduce microbial contamination and increase shelf life. Ninety-six carcasses were obtained from a local processor prior to final wash. On arrival at the research facility all carcasses were inoculated with 1 mL of a culture with 10(3) cfu/mL Listeria monocytogenes. After a 30-min attachment time, carcasses were subjected to a 4-s in-out final wash, hung for 3 min, and chilled in ice-water for 45 min. After the chilling, wings were removed by hand with a knife, pooled together, and subjected to a hand spray (4 mL/wing) with deionized water or Safe2O Poultry Wash. Two wings were then placed in each of 96 ziplock type storage bags, and wings were held at 5 +/- 1 degrees C for 3, 7, 10, and 14 d. On the day of sample, weep was decanted, and 100 mL of Butterfield's phosphate buffer was added to each bag. Three sets of wings were shaken by hand for 1 min, and total aerobes, Pseudomonads, Staphylococcus sp., psychrotrophic bacteria, and L. monocytogenes in the rinsates were enumerated. By using 7 log10 recovery of total aerobes from rinsates as a spoilage baseline, all wings were spoiled by d 10, but the wings treated with water were approaching spoilage counts on d 7, (log10 6.8), whereas only log10 5.5 bacteria were recovered from the wings sprayed with Safe2O Poultry Wash. Fewer Pseudomonads, Staphylcoccus sp., L. monocytogenes, and psychrotrophic bacteria were recovered from wings treated with Safe2O Poultry Wash and stored for 10 d. Log10 counts for the organisms were Pseudomonas sp., 8.2 and 6.9; Staphylcoccus sp., 5.5 and 4.9; L. monocytogenes, 5.2 and 4.6; and psychrotrophs, 8.2 and 6.9 for the water and Safe2O Poultry Wash treatments, respectively. Use of the Safe2O Poultry Wash as a postchill treatment on wings could increase the shelf life of wings by up to 3 d.

Development of an in vitro, isolated, infected spore testing model for disinfectant testing of Microsporum canis isolates

The isolated infected hair model is a commonly used technique to test the fungicidal efficacy of topical therapies against Microsporum canis. The most commonly used model uses mats of infective hairs, and results from various laboratories have differed. The objectives of this study were to develop a method to produce spores for testing when only mycelial forms were available and to develop a semiquantitative testing method that used only infective spores from hairs, and not pooled hair samples for testing. Ten isolates of M. canis were used in this study. Juvenile guinea pigs were easily infected using mycelial forms of M. canis and large numbers of spores were easily harvested for testing. Eight dilutions of disinfectants were tested. Fungal culture data were evaluated using an endpoint dilution at which there was 100% fungicidal activity, i.e. no growth on the plates. The 10 samples showed identical results. Chlorhexidine and Virkon(R) S were ineffective even when used at x4 the manufacturer's recommended dilution. Lime sulphur (1 : 33), enilconazole (20 microL mL(-1)), and bleach (1 : 10) were consistently effective when used at the recommended dilution. In addition, lime sulphur and enilconazole were 100% fungicidal even when the recommended concentration was diluted 1 : 4 or x4 as dilute as recommended.

Use of a topical disinfectant as part of a hoof care programme for horses with diseases of the hoof capsule

Twenty-three horses with persistent hoof horn defects were treated topically with a hoof disinfectant as part of a hoof care programme for a year. The active ingredients of the disinfectant were a poloaximer-iodine complex, ethylenediamine dihydriodide, isopropyl alcohol and propylene glycol. Hoof trimmings were taken at the start of the study and every six weeks, and examined by scanning and transmission electron microscopy. At the beginning of the study all the horn samples contained large numbers of bacteria, and samples from eight of the horses also had fungal hyphae intermingled with the bacteria. After the application of the hoof disinfectant and adjustments to their diet, there were rapid improvements in the gross appearance of the feet of all the horses; some of them improved within two to three weeks and by 12 weeks the horn quality of all the horses had greatly improved.

Biocide squirting from an elastomeric tri-layer film

Protective layers typically act in a passive way by simply separating two sides. Protection is only efficient as long as the layers are intact. If a high level of protection has to be achieved by thin layers, complementary measures need to be in place to ensure safety, even after breakage of the layer-an important issue in medical applications. Here, we present a novel approach for integrating a biocide liquid into a protective film (about 300-500 microm thick), which guarantees that a sufficient amount of biocide is rapidly released when the film is punctured. The film is composed of a middle layer, containing the liquid in droplet-like compartments, sandwiched between two elastomeric boundary layers. When the film is punctured, the liquid squirts out of the middle layer. A theoretical model was used to determine the size and density of droplets that are necessary to ensure a sufficient quantity of biocide is expelled from an adequately elastic matrix to provide protection at the site of damage. We demonstrate the utility of this approach for the fabrication of surgical gloves.

Agents for intraocular surgery

No single viscoelastic material has all the properties required for every surgical procedure. Ophthalmic surgeons should be familiar with the advantages and disadvantages of several viscoelastics and realize the limitations encountered if the surgeon chooses to rely on a single viscoelastic. It is possible in the future that newer viscoelastics may become available offering aspects of cohesive and dispersive properties that make them easy to remove and not associated with postoperative hypertension. Investigation into other types of viscoelastic materials, such as poly-acrylamide (Orcolon) [33,51,52], human collagen [33,53], polytriethylene-glycol monomethacrylate, and polyglycerol monomethacrylate [48], may result in the availability of synthetic viscoelastic materials. Rethinking how we use viscoelastics may also be indicated. The approach of a single or repeat instillation of a viscoelastic only to have it aspirated during the procedure could be modified by using a continuous infusion ofa dilute viscoelastic [54]. One study diluted hyaluronic acid to a concentration of 0.06% to 0.12% and maintained continuous infusion of the viscofluid through the PE irrigation line [54]. It has been suggested that this may reduce turbulence and improve tissue protection [54].

Formalin assay parameters differ in confirming the antinociceptive mechanism of domperidone in mice

Domperidone, a prokinetic drug with minimal extrapyramidal side-effects was investigated for its antinociceptive response in mice using formalin assay procedure. Two parameters namely the pain score and the time spent by the animal in licking/biting the formalin injected paw were considered. Domperidone (1, 2.5 or 5 mg/kg; ip) injected 15 min prior to formalin effectively reduced the pain score bringing it to zero at the 15th minute and was also effective till 30 min but to a lesser degree. This effect of domperidone (2.5 mg/kg) was significantly attenuated in naloxone pretreated mice indicating a partial role for opioid pathways. In the other parameter i.e. time spent in licking/biting, domperidone in all the doses employed failed to modify significantly the same by the animal in the early phase. In contrast, a dose related inhibition of the time spent was recorded in the late phase. Besides, a trend towards the enhancement of the inhibitory effect of domperidone (2.5 mg/kg) in the late phase was noticed in naloxone pretreated mice. Possibly, the peripheral analgesic mechanisms may play a role in this response since the late phase was considered akin to inflammation. The results confirm the antinociceptive effect of domperidone and suggest that caution be exercised while selecting the parameters when formalin assay is employed.

Ear cleaning: the UK and US perspective

Ear cleaning helps maintain the normal otic environment and is important in the treatment of otitis. Over cleaning, however, may trigger otitis through maceration of the epidermal lining. Simple manual cleaning is useful for routine cleansing but doesn't remove tightly adherent debris. Bulb syringes are more vigorous but may damage the ear in inexperienced hands. Devices using mains water pressure or dental machines are also available. Thorough cleaning of the ear canals and middle ear cavity can only be achieved by retrograde flushing using specially adapted catheters, feeding tubes or video otoscopes under anaesthesia. Myringotomy, inspection and cleaning of the middle should be performed if the tympanic membrane appears abnormal. There are a wide variety of cleaning fluids available. Ceruminolytics soften and dissolve cerumen to facilitate cleaning. Surfactants emulsify debris, breaking it up and keeping it in solution. Astringents dry the ear canal surface, preventing maceration. Maintaining a low pH and incorporating antimicrobial agents can inhibit microbial proliferation and glucocorticoids can be used to reduce inflammation. Adverse effects and contraindications following ear cleaning can include maceration, contact reactions, otitis media, ear canal avulsion, vestibular syndrome, Horner's syndrome, facial nerve paralysis and deafness. Care should be exercised in selecting cleaning fluids if the tympanic membranes are ruptured.

A distributed-parameter model for formaldehyde uptake and disposition in the rat nasal lining

DNA-protein cross-links (DPX) serve as a dosimeter for inhaled formaldehyde and are associated with tumor induction in rat nasal passages after chronic exposure to 6 ppm and above. To determine the role of epithelium-specific morphometry in formaldehyde-induced patterns of injury, we developed a mathematical model that links airflow-driven formaldehyde uptake with DPX formation in regions of the rat nose with high and low tumor incidence. A three-dimensional, anatomically accurate computational fluid dynamics model of rat nasal airflow and inhaled gas uptake was integrated with a physiologically based mathematical model incorporating tissue thickness, formaldehyde diffusion, its removal by enzymatic and nonenzymatic processes, and DNA distribution in the nasal mucosa to predict DPX formation. The model implicitly incorporates the reversible conversion of formaldehyde to methylene glycol. Where possible, parameter values were taken from the literature or estimated using published correlations. The Michaelis-Menten kinetic constants Vmax and Km, as well as a first-order constant for formaldehyde removal, were left as fitted parameters. The resultant model fit to the experimentally measured DPX in the high- and low-tumor-incidence regions of the rat nasal passages was very good. Sensitivity analysis indicates that among the fitted parameters, model fits are most sensitive to Vmax and that predictions were sensitive to changes in tissue thickness when all other parameters are held constant. The model structure facilitates extrapolation to primates and humans and application to other soluble, reactive gases.

[Pseudomonads in a new hospital building]

Testing the piping of a new hospital showed that the drinking water was contaminated with Pseudomonas aeruginosa. Because of pollution the plumbing system was treated with oxidizing biocides and air-water flushing for several times, unfortunately without stopping the bacterial recontamination. The reasons were firstly stagnation due to dead legs in the piping system, oversized pipes, very low water exchange rates and the installation of a catch water system, secondly low flow velocity because of low water pressure. After these sources of recontamination had been repaired, chlorine dioxide sanitization could be stopped successfully

Swelling of cattle heel horn by urine

OBJECTIVES

To understand the likely mechanisms responsible for heel horn softening when cattle stand in their own effluent. To examine the effectiveness of some footbath chemicals in preventing heel horn softening.

PROCEDURE

Shavings from the heels of cattle were used in a laboratory test to examine the swelling effects of cow urine, urea, sulphide and ammonia. Formalin, glutaraldehyde, glyoxal, zinc sulphate, copper sulphate, alum, tannic acid and a compound containing nitrocellulose plus nylon, were compared for their ability to prevent swelling in heel shavings induced by urea plus 2-mercaptoethanol.

RESULTS

Cow urine caused heel horn to swell. Urea caused swelling at concentrations normally found in cow urine. Sulphide caused swelling at concentrations normally found in cow slurry. Low concentrations of ammonia solution also resulted in swelling. Formalin and glutaraldehyde prevented swelling induced by high concentrations of urea plus 2-mercaptoethanol. Copper sulphate had a moderate anti-swelling effect. Zinc sulphate, alum, tannic acid, and nitrocellulose plus nylon were relatively ineffective in preventing swelling.

CONCLUSIONS

Cow urine can cause degradation of heel horn in cattle feet. The chemical agents that cause this could be urea, sulphide anions and ammonia. Degradation by urine can be prevented by pretreating heel horn with formalin. Glutaraldehyde may be an effective noncarcinogenic alternative to formalin.

A 3‐Year Follow‐Up Study of Anti‐ Legionella Antibodies in Users of Japanese 24‐Hour Hot Water Baths

Although it has been found that legionellae can exist in a 24-h hot water bath (24HHWB), which has been used recently in Japan, whether longer use of the 24HHWB causes legionellosis is unclear. The present longitudinal study was conducted in 2000 to investigate the 3-yr change in antibody titers in association with the continuous use, non-use, or canceling the use of the 24HHWB, and possible factors relating to the antibody changes. Ninety-two subjects (85 males and 7 females), who had had their anti-Legionella pneumophila (Lp) serum antibody titers measured in our initial study in 1997 and consented to blood sampling 3 yr later, were selected as subjects. There were no clinical cases who had experienced Legionnaires' disease or Pontiac fever during the 3 yr. The continuous users showed no significant changes in antibody titers within 3 yr, whereas the continuous non-users had a significant increase in antibody titers against the Lp serogroup (SG) 5 and 6. Eleven ex-users of the 24HHWB showed a significant decrease in antibody titers against Lp SG 6. The changes in the 24HHWB use, job sector, stress coping strategies, and alcohol-drinking habit were associated with the changes in antibody titers against Lp SG 1, 5 or 6. The anti-Lp antibodies were considered to be IgM dominant. In conclusion, this study indicates that 24HHWB use by healthy subjects does not tend to result in a higher onset risk of legionellosis, even if it is continuously used for 3 yr, although 24HHWB use is likely to induce production of antibodies against legionellae.

Acute neuropathy and erythromelalgia following topical exposure to isopropanol

Adverse effects resulting from topical exposure to isopropanol appears exceptional in adults with intact skin. We describe the case of a young woman who developed an acute sensori-motor axonal polyneuropathy after walking bare-feet for several hours on carpets soaked by a disinfectant containing isopropanolol. The persistence and severity of symptoms raised the possibility of her neuropathy being partly related to immunizations she received 1 mo earlier. The occurrence shortly after contact, however, strongly suggested responsibility of the dermal isopropanol exposure. This case being, to our knowledge, the second reported, peripheral nerve toxicity appears possible in adults on prolonged topical exposure, probably in susceptible individuals.

Dissolution of pulp tissue by aqueous solution of chlorhexidine digluconate and chlorhexidine digluconate gel

AIM

To evaluate the activity of various root canal irrigants on bovine pulp tissue.

METHODOLOGY

The irrigants tested were: 0.5, 1.0 and 2.5% sodium hypochlorite; 2% aqueous solution of chlorhexidine digluconate; 2% chlorhexidine digluconate gel (Natrosol); and distilled water as control. Bovine pulp fragments were weighed and placed in contact with 20 mL of each tested substance in a centrifuge at 150 r.p.m. until total dissolution. Dissolution speed was calculated by dividing pulp weight by dissolution time. Statistical analysis was performed using the Kruskal-Wallis test.

RESULTS

Distilled water and both solutions of chlorhexidine did not dissolve the pulp tissue within 6 h. Mean dissolution speeds for 0.5, 1.0 and 2.5% sodium hypochlorite solutions were 0.31, 0.43 and 0.55 mg min(-1), respectively. The solvent ability of chlorhexidine solutions was similar to that of distilled water. The results for sodium hypochlorite solutions, chlorhexidine solutions and distilled water were statistically different (P>0.01).

CONCLUSIONS

Both chlorhexidine preparations and distilled water were not able to dissolve pulp tissue. All sodium hypochlorite solutions were efficient in dissolving pulp tissue; the dissolution speed varied with the concentration of the solution.

[Prevention and control of respiratory tract infections in the network of Italian Centers for Cystic Fibrosis]

Infections caused by respiratory pathogens such as Burkholderia cepacia and Pseudomonas aeruginosa are associated with an increased morbidity and mortality in people affected by cystic fibrosis, the most common lethal genetic disease in Caucasian populations. Preventing the acquisition of these pathogens is paramount for these patients. The goal of this survey was to assess the distribution and the prevalence of the measures adopted for the prevention and control of infections caused by respiratory pathogens in the 28 italian centres for cystic fibrosis. 21 questionnaires were returned and some important differences can be observed in the adoption of segregation measures. Although results may be influenced by other factors, specific segregation policies appear to be more directly associated than other measures (e.g., intensive disinfection; behavioural rules to minimise patient' contacts) with lower prevalence of Pseudomonas aeruginosa (OR 0.36 CI95% 0.31-0.42), of multidrug-resistant Pseudomonas aeruginosa (OR 0.30 CI95% 0.22-0.40), and of methicillin-resistant Staphylococcus aureus (OR 0.67 CI95% 0.48-0.94).