Search

The synthesis of new 2-(3-bromo-5-isoxazolylideneamino-oxy)acetic acids and their condensation derivatives with suitable beta-lactam nuclei is reported. Their antibacterial properties have been tested in vitro. An interesting activity against Gram-positive bacteria including beta-lactamase-producing microorganisms was found among the cephalosporanic acid derivatives.

The synthesis of 3-bromo-4,5,6,7-tetrahydro-1,2-benzoisoxazole derivatives and their activity against human pathogen fungi are reported. In particular, compound 3,5-dibromo-6,7-dihydro-1,2-benzoisoxazol-4-(5H)-one showed a broad antifungal spectrum and good fungicidal activity against Trichophyton mentagrophytes.

Simulation of a therapy head for 6 MeV electron beams. We present the results of a simulation, performed using a Monte Carlo method, of depth dose curves in water for electron beams of initial kinetic energy of 6.4 MeV, generated by a radiotherapy microtron MM22 Scanditronix. The Fortran code in EGS4: comparison is made between simulated curves, obtained using various approximation criteria, and the experimental one.

Human intestinal flora from normal subjects was incubated with chenodeoxycholic acid (CDCA), ursodeoxycholic acid (UDCA) and 7-ketolithocholic acid (7-keto-LCA) for various periods of time and the metabolites thus formed were quantitatively determined by gas chromatography (GC) and identified by gas chromatography-mass spectrometry (GC-MS). Results showed that: a) the 7 alpha-dehydroxylation of CDCA produced more lithocholic acid more rapidly than the 7 beta-dehydroxylation of UDCA; b) the oxidation of CDCA produced more 7-keto-LCA more rapidly than the oxidation of UCDA; and c) the transformation of 7-keto-LCA produced CDCA and UDCA peaks after 8 h of incubation and a lithocholic peak at the end of 24 h of incubation after rising from almost 0% at 4 h. The presence of 3 alpha-hydroxy-delta 6-5 beta-cholenic acid, a hypothetical unsaturated intermediate in the 7-dehydroxylation of CDCA and UDCA, could not be detected by GC-MS.

The release into environment of liquid radioactive wastes coming from the metabolic therapy department of the Spedali Civili in Brescia was monitored during six months, with a rate of release of about 20 divided by 50 mCi of 131I every 30 divided by 40 days. Samples of 10 liters of liquid, taken from sewers downstream from the release point during a release operation, was percolated on 50 cm3 of ionic exchange resin in order to achieve a suitable counting rate with a Ge(Li) crystal spectrometer, connected to a 2048 channel analyzer. From these measurements a dilution curve along the sewers course was obtained, allowing one to know, for a given radioiodine concentration at the release point, concentration at every point downstream. In this way, by means of a simple linear compartmental model, it is possible to calculate the average individual dose taken by individuals who are living in the region (250.000 inhabitants) in one year of release operations. In our case we considered, as critical pathways to man, cow milk, meat, cereals and fruits: we obtained for thyroid, which in the case of radioiodine is the critical organ, an individual annual dose of 5,41 x 10(-4) mrem, while for total body we obtained 9,49 x 10(-7) mrem.

The synthesis of new 2-(3-substituted-5-isoxazolyl)-2-methoxyiminoacetic acids and their condensation derivatives with a suitable cephalosporanic nucleus, is reported. Their antibacterial properties were tested in vivo and in vitro also against beta-lactamase producer microorganisms; particularly the oral bioavailability of some of these new derivatives was studied.

An in vitro study was made of the bactericidal activity against Escherichia coli of fosfomycin trometamol, a new fosfomycin salt characterized by high bioavailability in relation to the pH, inoculum and culture medium, the latter being nutrient broth or human urine. Cotrimoxazole and norfloxacin were used for comparison. The results obtained show that both in nutrient broth and human urine, fosfomycin trometamol had higher bactericidal action than that of the other two antimicrobial agents.

The in vitro transformation, under anaerobic conditions, of 3- and 7-monosulfated and unsulfated bile acids, was studied in incubates of fecal flora from three healthy subjects. Chenodeoxycholic acid 7 alpha-sulfate and ursodeoxycholic acid 7 beta-sulfate were recovered unchanged, in all cultures, at the end of the incubation time. 3-Sulfated bile acids were metabolized in a different way by the three stool specimens. During the transformation of chenodeoxycholic acid 3-sulfate, desulfation, 7-dehydroxylation and 3-epimerization were observed. In contrast, 3-epimerization was not noticed when ursodeoxycholic acid 3-sulfate and lithocholic acid 3-sulfate were metabolized, the latter being principally transformed into delta 3-cholenic acid, probably by a bacterially mediated trans-elimination of sulfate group. The results obtained seem to prove that the presence of a SO3H group in 7-position usually hinders microbial transformations, which are not affected by a sulfate group in 3-position. Moreover, the 3-sulfated bile acids proved to be less sensitive to the microbial action than the corresponding unsulfated acids, with exception of lithocholic 3-sulfate.

In vitro thiamphenicol antibacterial activity in the presence of N-acetylcysteine as sodium salt proved to be enhanced when compared with that of the antibacterial alone against both Gram-positive and Gram-negative bacterial strains. The in vitro results were confirmed in vivo in the guinea-pig, where the sera from animals previously treated by i.m. route with thiamphenicol glycinate acetylcysteinate, showed a higher antibacterial activity than sera from animals treated with thiamphenicol glycinate hydrochloride. The observation, even after allowing for differences between species might be of some interest in view of use of this chemotherapeutic agent in the treatment of respiratory infections.