RESUMO
An efficient asymmetric synthesis of trans-4,5-disubstituted γ-butyrolactones from aldehydes and enantioenriched γ-carbamate alkenylboronates is reported. The cornerstone of this strategy is the implementation of sequential [3,3]-allyl cyanate rearrangement/allylboration/nucleophilic addition/cyclisation reactions. Diverse γ-butyrolactones such as the flavouring compounds, (+)-trans-whiskey lactone and (+)-trans-cognac lactone, as well as an advanced intermediate towards the first synthesis of natural products, (-)-nicotlactone B and (-)-galbacin, have thus been obtained.
RESUMO
Computer-assisted microscope analyses of Feulgen-stained nuclei were used to quantitatively describe the chromatin pattern and to determine the DNA ploidy level in a series of 70 cases including 46 low-grade (benign) ependymomas, 17 anaplastic (malignant) ependymomas, 3 choroid plexus papillomas (benign) and 4 choroid plexus carcinomas (malignant). While the quantitative description of the chromatin pattern was carried out by means of 14 morphonuclear parameters relating to geometric, densitometric and textural features, the DNA ploidy level was assessed by means of DNA histogram typing. Of these 70 cases, proliferative activity was assessed on 24, for which tissue was still available after the digital cell image analyses. This assessment was carried out by means of the determination of the immunohistochemical MIB-1 staining relating to the Ki-67 antigen. The results show that the determination of morphonuclear characteristics did not make it possible to distinguish between ependymal and choroid plexus tumours. Furthermore, neither the computer-assisted microscope analyses of morphonuclear characteritics nor the DNA ploidy level determination made it possible to distinguish between low-grade and anaplastic ependymomas. In sharp contrast, the determination of proliferative activity by means of the Ki-67 antigen immunohistochemical staining enabled such a distinction to be made.
RESUMO
The chromatin pattern in Feulgen-stained nuclei from soft tissue tumors was quantitatively described by means of computer-assisted microscope analysis. The morphonuclear parameters described densitometric, run length, and co-occurrence matrix features. The present series of cases, which relied upon archival (ie, formalin-fixed, paraffin-embedded), tissues, included 19 benign (9 lipomas and 10 leiomyomas) cases, and 49 malignant (31 primitive non-recurrent, 14 primitive locally recurrent, and 4 metastatic) cases. The 31 primitive nonrecurrent cases included 12 liposarcomas, 11 leiomyosarcomas, 4 rhabdomyosarcomas, and 4 malignant fibrohistiocytomas. The results show that the quantitative description of chromatin patterns in Feulgen-stained nuclei made it possible to distinguish between certain benign and malignant soft tissue tumors. However, this was true only when specific histopathologic groups were taken into consideration. Indeed, the lipomas were markedly different from the liposarcomas, whereas the leiomyomas closely resembled the leiomyosarcomas. The quantitative description of the chromatin patterns also made it possible to identify certain clinically aggressive soft tissue tumors. In this context, the authors observed that the chromatin pattern in the cell nuclei from the group of patients whose tumors had recurred less than 10 months after first surgery was significantly more heterogeneous and less condensed than in the cell nuclei from patients whose tumors had recurred more than 10 months after this surgery. In the same manner, the morphonuclear parameters under study made it possible to establish a more marked distinction between the primitive and recurrent soft tissue tumors that developed a metastasis between 3 and 48 months after the diagnosis, and those tumors free of metastasis until 38 months after the diagnosis. The former group exhibited cell nuclei with a chromatin pattern markedly more condensed and heterogeneous than in the case of the cell nuclei belonging to the latter group.