Microencapsulation of DEET in Solid Lipid Microparticles: production, characterization and safety evaluation.

DEET is considered the gold standard for insect repellent products. However, it behaves as a strong skin permeant. DEET was encapsulated in Solid Lipid Microparticles (SLM) and characterized in terms of morphology, particle size, cytotoxicity and ex vivo permeation. The particles exhibited micrometric size with a spherical shape. In addition, we developed and validated an analytical method for DEET quantification by high performance liquid chromatography (HPLC), which was selective, linear, precise, accurate and robust. The toxicity test in cell culture of keratinocytes, fibroblasts and macrophages showed that the formulation did not present cytotoxicity. The SLM were able to decrease the skin permeation of DEET in relation to the free active in ethanol with gain in the safe. Microparticles were able to increase the skin retention of DEET, which can contribute to extend the time of repellent action. The results showed that Solid Lipid Microparticles are safe and promising topical formulation to insect bite prevention.

Gene homozygosis and mitotic recombination induced by camptothecin and irinotecan in Aspergillus nidulans diploid cells.

Mitotic recombination is a process involved in carcinogenesis which can lead to genetic loss through the loss of heterozygosity. The recombinogenic potentials of two anticancer drugs topoisomerase I inhibitors, camptothecin (CPT) and irinotecan (CPT-11), were evaluated in the present study. The homozygotization assay, which assess the induction of mitotic recombination and gene homozygosis, as well as the heterozygous A757//UT448 diploid strain of Aspergillus nidulans were employed. The three non-cytotoxic concentrations of CPT (3.5 ng mL-1, 10.5 ng mL-1 and 17.4 ng mL-1) were found to induce both mitotic recombination and gene homozygosis. CPT treatment produced three diploids homozygous, for nutritional and conidia color genes, and Homozygotization Indices (HI) significantly different from negative control. On the other hand, only the highest CPT-11 concentration tested (18 µg mL-1), corresponding to the maximal single chemotherapeutic dose, produced HI values higher than 2.0 and significantly different from negative control HI values. The recombinogenic effects of both topoisomerase I blockers were associated with the recombinational repair of DNA strand breaks induced by CPT and CPT-11. The anticancer drugs CPT and CPT-11 may be characterized as secondary malignancies promoters in cancer patients after chemotherapy treatment.

Genome sequence of the emerging pathogen Aeromonas caviae.

Aeromonas caviae is a Gram-negative, motile and rod-shaped facultative anaerobe that is increasingly being recognized as a cause of diarrhea in children. Here we present the first genome sequence of an A. caviae strain that was isolated as the sole pathogen from a child with profuse diarrhea.

High frequency of hemolytic and cytotoxic activity in Aeromonas spp. isolated from clinical, food and environmental in Rio de Janeiro, Brazil.

Molecular study of aerolysin and cytotonic enterotoxin genes by PCR and colony blot hybridization was performed in 117 strains of Aeromonas spp. isolated from different sources. Homogeneous distribution of these genes in A. hydrophila complex strains was observed. For A. caviae and A. sobria complex strains, aerolysin genes were more frequent than cytotonic enterotoxins genes. Of 64 A. caviae complex strains, only one (1.5%) amplified the 451 bp product for the aer gene, however, the same primers detected a 400 bp product in 50 (78%) strains. This product was sequenced and had two short regions with homology to several hemolysin genes. The genotype aer (+)/aerA(+)/hly (+)/ast (+)/alt (+) was detected in six A. hydrophila strains from food and environmental source. The most common genotype found in A. hydrophila strains was hly (+) (85%) and aerA(+) (78.7%), while in A. caviae complex strains was aerA(+) (32.8%). All A. veronii complex sobria strains were aer (+)/aerA(+). All A. caviae and A. hydrophila were positive when tested with aer probe using the colony blot test. Thirty-seven percent of A. hydrophila and 53% of A. caviae tested were positive for ast probe. Eighty-nine percent of samples were cytotoxic in Vero cells. Our data demonstrated that Aeromonas spp. can harbor and express virulence genes and reinforce the potential of Aeromonas as a human pathogen.

Impact of acquisition geometry, image processing, and patient size on lesion detection in whole-body 18F-FDG PET.

UNLABELLED: The aim of this work was to develop a rigorous evaluation methodology to assess performance of different acquisition and processing methods for variable patient sizes in the context of lesion detection in whole-body (18)F-FDG PET. METHODS: Fifty-nine bed positions were acquired in 32 patients in 2-dimensional (2D) and 3-dimensional (3D) modes 1-4 h after (18)F-FDG injection (740 MBq) using a BGO PET scanner. Three spheres (1.0-, 1.3-, and 1.6-cm diameter) containing (68)Ge were also imaged separately in air, at locations corresponding to possible lesion sites in 2D and 3D (590 targets per condition). Each bed position was acquired for 7 min in 2D and 6 min in 3D and corrected for randoms using delayed window randoms subtraction (DWS) or randoms variance reduction (RVR). Sphere sinograms were attenuated using the 2D or 3D attenuation map derived from the transmission scan of the patient, after scaling 2D and 3D sinograms with identical factors to ensure marginal detectability. Resulting 2D sinograms were reconstructed with filtered backprojection (FBP) and ordered-subsets expectation maximization (OSEM) without any scatter or attenuation correction (FBP-NATS and OSEM-NATS) or corrected for scatter and attenuation and reconstructed using FBP (FBP-ATT) or attenuation-weighted OSEM (AWOSEM). 3D sinograms were processed identically after Fourier rebinning. Next, reconstructed volumes were compared on the basis of performance of a 3-channel Hotelling observer (CHO-SNR [SNR is signal-to-noise ratio]) in detecting the presence of a sphere of unknown size on an anatomic background while modeling observer noise. The noise equivalent count (NEC) rate was computed in 2D and 3D for 3 different phantoms sizes (40, 60, and 95 kg) and compared with lesion detection SNR. RESULTS: 3D imaging yielded better lesion detectability than 2D (P < 0.025, 2-tailed paired t test) in patients of normal size (body mass index [BMI] < or = 31). However, 2D imaging yielded better lesion detectability than 3D in large patients (BMI > 31), as 3D performance deteriorated in large patients (P < 0.05). 2D and 3D yielded similar results for different lesion sizes. CHO-SNR were 40% greater for AWOSEM, FBP-ATT, and FBPNAT than for OSEM (P < 0.05), and AWOSEM yielded significantly better lesion detectability than did FBP. In all patients, RVR yielded a systematic improvement in CHO-SNR over DWS in both 2D and 3D. radicalNEC was characterized by a behavior similar to that of SNR(CHO) for the 3 different phantom sizes considered in this study.