In vitro study of the efficacy of a two-way connection with disinfectant in the prevention of peritonitis.

A new connection system for continuous ambulatory peritoneal dialysis (CAPD) has been established, and its efficacy in preventing microbial contamination of the peritoneal cavity has been tested in vitro. The system consists of a Y-shaped channel formed in the bottom of a Plexiglas cup. The Luer-lock shaped ends of the Y-shaped channel are designed to host the connectors from the drainage bag, the catheter transfer set, and the bag of fresh dialysate. Because the connectors from the catheter transfer set and the fresh bag are located at the inner surface of the cup bed, and because the cup is filled with disinfectant during the entire exchange procedure, all at-risk steps are continuously protected by disinfectant (that is, removal of the caps from the connectors, connection and disconnection, replacement of the caps). Still, because the patient could inadvertently extract and contaminate one of the two connectors (although such a possibility is unlikely), the disinfecting efficacy of the system was tested in vitro. Despite contamination with various micro-organisms at the highest possible concentrations, all tests showed negative bacterial growth, thus confirming the absolute efficacy of the system in preventing exogenous transluminal peritonitis.

Mortality of plastic-ware workers exposed to radiofrequencies.

The mortality experience of a cohort of Italian plastic-ware workers exposed to radiofrequency (RF)-electromagnetic fields generated by dielectric heat sealers was investigated. Follow-up extended from 1962 to 1992. The standardised mortality ratio (SMR) analysis was restricted to 481 women workers, representing 78% of the total person-years at risk. Mortality from malignant neoplasms was slightly elevated, and increased risks of leukemia and accidents were detected. The all-cancer SMR was higher among women employed in the sealing department, where exposure to RF occurred, than in the whole cohort. This study raises interest in a possible association between exposure to RF radiation and cancer risk. However, the study power was very small, and the possible confounding effects of exposure to solvents and vinyl chloride monomer (VCM) could not be ruled out. The hypothesis of an increased risk of cancer after radiofrequency exposure should be further explored by means of analytical studies characterised by adequate power and more accurate exposure assessment.

New heterocyclic derivatives of benzimidazole with germicidal activity--XII--Synthesis of N1-glycosyl-2-furyl benzimidazoles.

Over the last decade, several derivatives of benzimidazole have been synthesized; some of them turned out to have a good antimicrobial activity; however, all of them were not soluble in water. Therefore the N1-heterosides of four derivatives of 2-(2'-furyl) benzimidazole, chosen from those with the highest biological activity have been now synthesized. These compounds were expected to have some new properties, including a good water-solubility and a higher or at least similar biological activity; furthermore, taking into account some previously published data on similar molecules, an antileukemic activity was expected. However, no one of these hypothesis was confirmed experimentally.

New heterocyclic derivatives of benzimidazole with germicidal activity--XI--Experimental validation of OSAR prediction on antibacterial and antimycotic activity of benzimidazole derivatives.

In continuation of previous studies, Authors describe the synthesis of three new derivatives of 2-(5'-nitro-2'-furyl) benzimidazole, having hydroxy, methoxy or amino group at position 5. The new compounds, synthesized as suggested by a previous chemometric study, were tested in vitro against 5 Gram + and 4 Gram- strains and the mycete C. albicans. Two derivatives (R = OH, NH2) showed a good degree of antibacterial activity, especially the 5-hydroxy derivative, but they were practically inactive against the mycete; these results are in agreement with the prediction of chemometric study.

New heterocyclic derivatives of benzimidazole with germicidal activity. X-In vivo toxicity of 5-fluoro-2-(5'-nitro-2'-furyl)-benzimidazole (F-O-NO2); preliminary observations.

The in vivo toxicity of 5-fluoro-2-(5'-nitro-2'-furyl) benzimidazole vehiculated in liposomes (L-FONO2), induced in mice by intraperitoneal injection, was evaluated. Toxicity was tested looking at the liver and kidney damage by determining some specific functional parameters (seric urea, seric GPT and urinary beta-NAG): no modifications were observed after administration of L-FONO2 for seven days.

New heterocyclic derivatives of benzimidazole with germicidal activity--IX--HPLC detection of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2) in biological samples.

The HPLC technique for the isolation and quantitation of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2), previously described by the same Authors, in biological samples from mice is reported. Evidence is given that the highest biological concentration and the time needed for reaching it depend both on the dose and on the administration route. In fact, almost the same maximal biological concentration of F-O-NO2 (about 0.18 micrograms/mouse) is reached after 60 min from either 40 mg/Kg IP or 200 mg/Kg os drug administration, whereas the maximal biological concentration of F-O-NO2 (5.75 micrograms/mouse) is reached after 30 min from 120 mg/Kg IP drug administration.

Methicillin-resistant staphylococcal strains isolated from clinical samples.

Infections caused by methicillin-resistant Staphylococcus strains (MRSS) have become an increasing problem both as community-acquired and nosocomial infections. In order to eradicate colonization as well as to cure infections, optimal antibiotic treatment is required. In this study we examined the incidence of MRSS in clinical samples and compared the antibiotic susceptibility pattern of methicillin-resistant Staphylococcus aureus with that of methicillin-resistant Staphylococcus non-aureus strains. All the MRSS were resistant to penicillin. Among them there was a variation in the percentage of strains resistant to various antimicrobial agents. Within MRSS the most frequent resistances were those to erythromycin and norfloxacin. Ciprofloxacin and teicoplanin were the most effective antibiotics tested against MRSS, followed in activity by vancomycin and imipenem. The incidence of antibiotic resistance among MRSS was significantly higher than that among methicillin-susceptibility staphylococcal species.

Chemometric approach in a QSAR study: the antibacterial and antimicotic activities of benzofused heteroaromatic derivatives.

In order to establish quantitative relationships between the antibacterial activities of a number of thienyl- and furyl-benzimidazoles and benzoxazoles, the biological data were measured homogeneously for a selected set of 16 representative compounds of the available set of 103. The data were analyzed by the PLS method. The results of linear PLS modelling and PLS response surface modelling permitted a straightforward interpretation of the structural features relevant to the activities and the prediction of a possible optimal structure.

New heterocyclic derivatives of benzimidazole with germicidal activity--VII--2-(5'-nitro-2'-furyl or 2'-thienyl) benzimidazoles with different substituents in the 5-position.

In continuation of our previous research, the synthesis of 13 2-(5'-nitro-2'-furyl or 2'-thienyl) benzimidazoles with different substituents in 5 position is described. The new compounds were tested in vitro against 5 (Gram+) and 4 (Gram-) strains and a mycete Candida Albicans. All the derivatives showed a certain degree of antibacterial and antimycotic activity, which in some cases was fairly good.

[New heterocyclic derivatives with germicidal activity. VI. Synthesis and activity of new 2-benzoxazoyl-2'-furanes and -thiophenes variously substituted in 5 and 5' positions]. / Nuovi derivati eterociclici ad attività germicida. VI. Sintesi ed attività di nuovi 2-benzossazolil-2'-furani e-tiofeni, variamente sostituiti in 5 e 5'.

Seventeen derivatives of 2'-furyl-2-benzoxazole and three derivatives of 2'-thienyl-2-benzoxazole, having different substituents in the benzene moiety (position 5) and in the furanic or thiophenic ring (position 5'), are described, with the aim of studying antibacterial and antimycotic structure-activity relationships. None of the compounds show an important antibacterial and/or antimycotic activity, when tested against nine bacteria and Candida albicans cultures; in any case it was much lower than that previously reported for the corresponding benzimidazoles. It seems that the = NH group of the imidazole ring, which is absent in the benzoxazole derivatives, might be important for the biological activity of this class of compounds.

[New heterocyclic derivatives of benzimidazole with germicidal activity. V. Synthesis and activity of new derivatives of di-2-benzimidazolyl-2,5-furan]. / Nouveaux derives heterocycliques du benzimidazole a activite germicide. V. Synthese et activité de nouveaux di-2-benzimidazolyl-2,5-furranes asymétriques.

In continuation of the research in the field of germicidal and antimycotic agents, the synthesis of 14 new derivatives of di-2-benzimidazolyl-2,5-furan is described. These derivatives are differently substituted (R not equal to R') in the position 5 of the two benzene rings. These new compounds showed no germicidal or fungicidal activity, when tested on different cultures. New compounds are under investigation.

Microbial flora of surface versus core tonsillar cultures in recurrent tonsillitis in children.

Surface and 'core' tonsillar specimens were collected from 60 children, between 2 and 14 years of age, suffering from recurrent tonsillitis, in order to establish the reliability of surface tonsillar swabbing technique and to define the most frequently involved aerobic and anaerobic microorganisms. From the qualitative point of view, the same mixed aerobic and anaerobic flora were obtained in both samples thus demonstrating the reliability of the surface swabbing technique. From the quantitative point of view, 187 microorganisms, 129 (69.2%) aerobes and 58 (30.8%) anaerobes were isolated from surface cultures while 184, 109 (59.2%) aerobes and 75 (40.8%) anaerobes from the core cultures, thus demonstrating a greater number of anaerobes in the core of the tonsil. The most common isolated aerobic microorganisms were the alpha- and beta-hemolytic Streptococci, the Neisseriae and the Staphylococcus aureus; the predominant anaerobic ones were the Fusobacterium nucleatum, the Bacteroides sp. and the Veillonella parvula. The isolated staphylococcus aureus and the bacteroides sp. were all beta-lactamase producers.

Comparative in vitro activity of imipenem against gram-positive and gram-negative aerobic bacteria from clinical isolates.

Imipenem is a member of a new class of beta-lactam antibiotics, carbapenems, with a very broad antibacterial spectrum. In this work we evaluated the in vitro activity of imipenem against a variety of bacterial strains isolated from clinical specimens as well as the activity of other beta-lactam antibiotics. The results obtained with 501 bacterial strains show that imipenem is active on both gram-negative and gram-positive microorganisms isolated from different infections. The in vitro inhibitory activity is greater than that of aztreonam, cefotaxime, ceftriaxone, piperacillin, amikacin, and netilmicin, against the majority of strains tested.

New heterocyclic derivatives of benzimidazole with germicidal activity. IV--In vivo anticandida activity of 5-fluoro-2-(5'-nitro-2'-furyl) benzimidazole (F-O-NO2).

We have studied the possible in vitro and in vivo antibacterial activity of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2). Our data demonstrate that F-O-NO2 is able to inhibit the in vitro growth of different mycetes and bacteria, including Candida albicans and Cryptococcus neoformans. We also tested the possible in vivo activity against Candida albicans. The results clearly show that treatment with F-O-NO2 is able to significantly augment the survival of all treated animals; in particular, when injected i.p. at the dose of 120 mg/kg, 30' or 1 hr after Candida albicans challenge, it givens a MST (Medium Survival Time) longer than 60 days. These data demonstrate that F-O-NO2 has antibacterial and antimycotic activity.

Microbial flora of nose and paranasal sinuses in chronic maxillary sinusitis.

Nasal secretions, maxillary sinus aspirates and specimens of the maxillary sinus mucosa were collected in 44 patients aged between 25 and 60 affected by mono- or bilateral chronic maxillary sinusitis, in order to establish the best sampling technique for microbiological purposes, the most frequently involved bacteria and the physiopathological mechanism underlying chronic maxillary disease. The sinusal mucosa resulted to be the most reliable sample as it reduces contamination and microbial variability. Anaerobic bacteria were isolated in nasal swab (15.6%), in maxillary sinus aspirates (30.4%) and in maxillary sinus mucosa (36.4%) of maxillary sinusitis patients. In controls anaerobic bacteria were isolated only in one nasal swab (2.3%), while they could not be isolated in maxillary sinus aspirates and in maxillary sinus mucosa. The presence of anaerobic bacteria in chronic maxillary sinusitis patients and their absence in controls seem to confirm that anaerobic microorganisms represent the main pathogenetic agents of chronic maxillary sinusitis. The possible physiopathological mechanisms underlying chronic maxillary sinus disease are finally discussed.

[New heterocyclic derivatives of benzimidazole with germicidal activity. III. Synthesis and activity of derivatives of (formyl-5'-furyl-2')-2-benzimidazole with different substitutions at position 5]. / Nouveaux dérivés hétérocycliques du benzimidazole à activité germicide. III--Synthèse et activité de derivés du (formyl-5'-furyl-2')-2-benzimidazole, différemment substitués en position 5.

The synthesis and germicidal properties of 28 new derivatives of furyl-2-benzimidazole are described. The compounds are substituted both in position 5 of the benzene moiety and in position 5' of the heterocycle moiety. The germicidal properties of the new molecules were tested using 9 strains of bacteria and Candida albicans. Some of them exhibited germicidal properties versus Gram + bacteria and versus Candida. Some derivatives were also tested using Mycobacterium aurum: two isonicotinoylhydrazones derivatives exhibited tubercolostatic activity comparable to that of streptomycin and not much lower than that of isoniazide.

Turkey red blood cell passive haemagglutination assay as guideline for specific prevention of tetanus in injured persons.

Turkey red blood cell passive haemagglutination assays (TRBC-HA) were carried out on serum samples from 873 injured patients in order to compare individual prophylactic treatment against tetanus based on the anti-tetanus antibody levels with interventions based on anamnestic criteria. The results showed a great difference: according to the anamnesis 124 persons (14.2%) were protected, 253 (29%) were partially protected, and 496 (56.8%) were unprotected; according to the TRBC-HA assay, 479 (54.9%) were protected, 279 (32%) partially protected, and 115 (13.2%) unprotected.The efficiency of the prophylactic treatments given on the basis of the two criteria was also compared in a study of 129 injured patients who were divided in two groups: group 1 (50 patients) received 250 IU of human tetanus immunoglobulin (HTI) regardless of their tetanus immunity, and group II (79 patients) received appropriate or no treatment depending on the level of anti-tetanus antibodies determined by TRBC-HA assay. The results showed that prophylactic interventions based on the anti-tetanus antibody levels can give protection in 100% of injured patients at minimum cost and risk.