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1.
Org Biomol Chem ; 10(2): 361-6, 2012 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-22080402

RESUMO

The synthesis of a novel D-ring modified docetaxel analogue, in which the oxetane ring is replaced with a γ-lactone, was achieved from 10-deacetylbaccatin III. The key steps of the synthesis include the direct acetylation of the secondary hydroxyl group at C-5 and D-ring opening and intramolecular aldol reaction to form the γ-lactone. In MTT assays, this analogue proved to have equipotent cytotoxicity relative to paclitaxel towards HCT8, HePG2 and BGC23 cancer cell lines, and be more potent than paclitaxel against A549 and A375. It represents the first example of D-ring modified taxoids with significant cytotoxicity.


Assuntos
Antineoplásicos/farmacologia , Lactonas/química , Taxoides/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Docetaxel , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Conformação Molecular , Estereoisomerismo , Relação Estrutura-Atividade , Taxoides/síntese química , Taxoides/química
2.
J Spinal Disord Tech ; 24(6): E49-56, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21685804

RESUMO

STUDY DESIGN: An in vitro biomechanical cadaver study. OBJECTIVES: To evaluate the pull-out strength after 5000 cyclic loading among 4 revision techniques for the loosened iliac screw using corticocancellous bone, longer screw, traditional cement augmentation, and boring cement augmentation. SUMMARY OF BACKGROUND DATA: Iliac screw loosening is still a clinical problem for lumbo-iliac fusion. Although many revision techniques using corticocancellous bone, larger screw, and polymethylmethacrylate (PMMA) augmentation were applied in repairing pedicle screw loosening, their biomechanical effects on the loosened iliac screw remain undetermined. METHODS: Eight fresh human cadaver pelvises with the bone mineral density values ranging from 0.83 to 0.97 g/cm were adopted in this study. After testing the primary screw of 7.5 mm diameter and 70 mm length, 4 revision techniques were sequentially established and tested on the same pelvis as follows: corticocancellous bone, longer screw with 100 mm length, traditional PMMA augmentation, and boring PMMA augmentation. The difference of the boring technique from traditional PMMA augmentation is that PMMA was injected into the screw tract through 3 boring holes of outer cortical shell without removing the screw. On an MTS machine, after 5000 cyclic compressive loading of -200∼-500 N to the screw head, axial maximum pull-out strengths of the 5 screws were measured and analyzed. RESULTS: The pull-out strengths of the primary screw and 4 revised screws with corticocancellous bone, longer screw and traditional and boring PMMA augmentation were 1167 N, 361 N, 854 N, 1954 N, and 1820 N, respectively. Although longer screw method obtained significantly higher pull-out strength than corticocancellous bone (P<0.05), the revised screws using these 2 techniques exhibited notably lower pull-out strength than the primary screw and 2 PMMA-augmented screws (P<0.05). Either traditional or boring PMMA screw showed obviously higher pull-out strength than the primary screw (P<0.05); however, no significant difference of pull-out strength was detected between the 2 PMMA screws (P>0.05). CONCLUSIONS: Wadding corticocancellous bone and increasing screw length failed to provide sufficient anchoring strength for a loosened iliac screw; however, both traditional and boring PMMA-augmented techniques could effectively increase the fixation strength. On the basis of the viewpoint of minimal invasion, the boring PMMA augmentation may serve as a suitable salvage technique for iliac screw loosening.


Assuntos
Cimentos para Ossos , Parafusos Ósseos , Ílio/cirurgia , Vértebras Lombares/cirurgia , Falha de Prótese , Idoso , Fenômenos Biomecânicos , Feminino , Humanos , Fixadores Internos , Masculino , Pessoa de Meia-Idade , Reoperação
3.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 3): o577, 2011 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-21522339

RESUMO

The title compound, C(18)H(21)NO(3), was obtained via a double Mannich condensation reaction of 6-methyl-tetra-hydro-isobenzofuran-1,7(3H,7aH)-dione with formaldehyde and benzyl-amine. The mol-ecule contains three fused rings of which the cyclo-hexa-none and piperidine rings adopt chair conformations and the furan-one ring assumes an envelope conformation. An inter-molecular C-H⋯π inter-action is present in the crystal structure.

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