| 11. |
- Padrela, Luis, et al.
(författare)
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Formation of indomethacin-saccharin cocrystals using supercritical fluid technology
- 2009
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 38:1, s. 9-17
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Tidskriftsartikel (refereegranskat)abstract
- The main objective of the present work is to check the feasibility of supercritical fluid (SCF) technologies in the screening and design of cocrystals (novel crystalline solids). The cocrystal formation tendencies in three different SCF techniques, focusing on distinct supercritical fluid properties - solvent, anti-solvent and atomization enhancer - were investigated. The effect of processing parameters on the cocrystal formation behaviour and particle properties in these techniques was also studied.A recently reported Indomethacin-Saccharin (IND-SAC) cocrystalline system was our model system. A 1:1 molar ratio of indomethacin (γ-form) and saccharin was used as a starting material. The SCF techniques employed in the study include the CSS technique (Cocrystallization with Supercritical Solvent), the SAS technique (Supercritical Anti-Solvent), and the AAS technique (Atomization and Anti-Solvent). The resulting cocrystalline phase was identified using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier Transform-Raman (FT-Raman). The particle morphologies and size distributions were determined using scanning electron microscopy (SEM) and aerosizer, respectively.The pure IND-SAC cocrystals were obtained from SAS and AAS processes, while partial to no cocrystal formation occurred in the CSS process. However, no remarkable differences were observed in terms of cocrystal formation at different processing conditions in SAS and AAS processes. Particles from CSS processes were agglomerated and large, whilst needle-to-block-shaped and spherical particles were obtained from SAS and AAS processes, respectively. The particle size distribution of these particles was 0.2 μm to 5 μm.Particulate IND-SAC cocrystals with different morphologies and sizes (nano-to micron) were produced using supercritical fluid techniques. This work demonstrates the potential of SCF technologies as screening methods for cocrystals with possibilities for particle engineering.
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| 12. |
- Albuquerque, Joaquim F. S., et al.
(författare)
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Adaptive changes of the enterochromaffin and gastrin cells in the rat gastrointestinal tract following subtotal colectomy
- 2006
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 41:8, s. 963-968
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Colectomized patients often have diarrhoea and increased gastric acid secretion. Although serotonin influences gastrointestinal (GI) motility and secretion, GI serotonin-producing enterochromaffin (EC) cells have not been investigated after colectomy, nor have the antral gastrin cells. The aim of this experimental study was to investigate the GI tract in rats 8 weeks after subtotal colectomy, with particular emphasis on the frequency and distribution of EC and gastrin cells. Material and methods. Immunohistochemical techniques were used to identify the two endocrine cell types. Results. The colectomized animals had diarrhoea. Body-weight was lower and the small intestine shorter in the colectomized animals compared with sham-operated and untreated controls. In the two surgically treated groups, the antral mucosa was thinner and the small intestinal mucosa was thicker compared with that of the untreated rats, whereas the thickness of the rectum of the colectomized rats was increased compared with that of the control groups. In the colectomized animals, the number of EC cells was increased in the small intestine and rectum, whereas the numbers of both EC and gastrin cells were decreased in the antrum. Conclusions. The results indicate that colectomy exerts a significant influence on the GI mucosa and on the endocrine cell systems studied. An increased number of EC cells can result in alterations in motility and secretion, which may be important in the pathogenesis of the diarrhoea that often occurs after colectomy.
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| 13. |
- dos Santos, F. Eroni P., et al.
(författare)
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Evaluation of the third-order nonlinear optical properties of tellurite glasses by thermally managed eclipse Z-scan
- 2009
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 105:2
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Tidskriftsartikel (refereegranskat)abstract
- The third-order nonlinearity is measured for TeO2-ZnO-Na2O (TZN) glasses codoped with BaO, Nb2O5, and La2O3. The results for the sign and magnitude of the nonlinearity were obtained using a combination of the eclipse Z-scan with thermal nonlinearity managed Z-scan, whereas the Kerr shutter technique was employed to obtain the electronic time response of the nonlinearity, all performed with 76 MHz repetition rate 150 fs pulses at 800 nm. The results show a fast response (< 200 fs) and a nonlinear refractive index varying from 1.5 to 3.5x10(-15) cm(2)/W, depending upon glass composition. At the peak power level employed, nonlinear absorption was negligible. The results obtained are in good agreement with other tellurite compositions reported, confirming the electronic origin of the nonlinearity.
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| 14. |
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| 15. |
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| 16. |
- Magalhães, Ana, et al.
(författare)
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Fut2-null mice display an altered glycosylation profile and impaired BabA-mediated Helicobacter pylori adhesion to gastric mucosa
- 2009
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 0959-6658 .- 1460-2423. ; 19:12, s. 1525-1536
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Tidskriftsartikel (refereegranskat)abstract
- Glycoconjugates expressed on gastric mucosa play a crucial role in host-pathogen interactions. The FUT2 enzyme catalyzes the addition of terminal alpha(1,2)fucose residues, producing the H type 1 structure expressed on the surface of epithelial cells and in mucosal secretions of secretor individuals. Inactivating mutations in the human FUT2 gene are associated with reduced susceptibility to Helicobacter pylori infection. H. pylori infects over half the world's population and causes diverse gastric lesions, from gastritis to gastric cancer. H. pylori adhesion constitutes a crucial step in the establishment of a successful infection. The BabA adhesin binds the Le(b) and H type 1 structures expressed on gastric mucins, while SabA binds to sialylated carbohydrates mediating the adherence to inflamed gastric mucosa. In this study, we have used an animal model of nonsecretors, Fut2-null mice, to characterize the glycosylation profile and evaluate the effect of the observed glycan expression modifications in the process of H. pylori adhesion. We have demonstrated expression of terminal difucosylated glycan structures in C57Bl/6 mice gastric mucosa and that Fut2-null mice showed marked alteration in gastric mucosa glycosylation, characterized by diminished expression of alpha(1,2)fucosylated structures as indicated by lectin and antibody staining and further confirmed by mass spectrometry analysis. This altered glycosylation profile was further confirmed by the absence of Fucalpha(1,2)-dependent binding of calicivirus virus-like particles. Finally, using a panel of H. pylori strains, with different adhesin expression profiles, we have demonstated an impairment of BabA-dependent adhesion of H. pylori to Fut2-null mice gastric mucosa, whereas SabA-mediated binding was not affected.
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| 17. |
- Nene, Vishvanath, et al.
(författare)
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Genome sequence of Aedes aegypti, a major arbovirus vector.
- 2007
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 316:5832, s. 1718-23
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Tidskriftsartikel (refereegranskat)abstract
- We present a draft sequence of the genome of Aedes aegypti, the primary vector for yellow fever and dengue fever, which at approximately 1376 million base pairs is about 5 times the size of the genome of the malaria vector Anopheles gambiae. Nearly 50% of the Ae. aegypti genome consists of transposable elements. These contribute to a factor of approximately 4 to 6 increase in average gene length and in sizes of intergenic regions relative to An. gambiae and Drosophila melanogaster. Nonetheless, chromosomal synteny is generally maintained among all three insects, although conservation of orthologous gene order is higher (by a factor of approximately 2) between the mosquito species than between either of them and the fruit fly. An increase in genes encoding odorant binding, cytochrome P450, and cuticle domains relative to An. gambiae suggests that members of these protein families underpin some of the biological differences between the two mosquito species.
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| 18. |
- Tamas, I, et al.
(författare)
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A combined approach exploring gene function based on Worm-Human Orthology
- 2005
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 6, s. 65-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Many aspects of the nematode Caenorhabditis elegans biology are conserved between invertebrates and vertebrates establishing this particular organism as an excellent genetic model. Because of its small size, large populations and self-fertilization of the hermaphrodite, functional predictions carried out by genetic modifications as well as RNAi screens, can be rapidly tested. Results: In order to explore the function of a set of C. elegans genes of unknown function, as well as their potential functional roles in the human genome, we performed a phylogenetic analysis to select the most probable worm orthologs. A total of 13 C. elegans genes were subjected to down-regulation via RNAi and characterization of expression profiles using GFP strains. Previously unknown distinct expression patterns were observed for four of the analyzed genes, as well as four visible RNAi phenotypes. In addition, subcellular protein over-expression profiles of the human orthologs for seven out of the thirteen genes using human cells were also analyzed. Conclusion: By combining a whole-organism approach using C. elegans with complementary experimental work done on human cell lines, this analysis extends currently available information on the selected set of genes.
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| 19. |
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| 20. |
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