Ultrastructure of the digestive system and the fate of midgut during embryonic development in Porcellio scaber (Crustacea: Isopoda).

Microscopic anatomy of the digestive system in embryos and larvae of the terrestrial isopod crustacean Porcellio scaber was investigated by light bright field, fluorescence and electron microscopy. During marsupial ontogenetic development the event-dependent staging was used to discriminate the various embryonic stages. At the late embryo stage the differentiation of the ectodermal part of the gut into the complex filtering foregut and the hindgut with absorptive and transporting functions is accomplished. The gut of the marsupial manca larva is fully developed and similar to that of the adult. In early embryos the endodermal midgut gland primordia are filled with yolk and lipid globules. In late embryos the epithelium of paired midgut gland tubes is composed of two cell types; one of them exhibits orange autofluorescence. The endodermal cells located between the foregut and the midgut glands of late embryos form the prospective midgut. The cells have electron dense cytoplasm, abundant glycogen fields, endoplasmic reticulum, dictyosomes and numerous vesicles. In the adults the endodermal cells of the midgut remain only in the midgut gland ducts which connect the midgut glands and the foregut. Details of the cellular ultrastructure and morphogenesis of the ectodermal and endodermal parts of the digestive system during embryonic development of Porcellio scaber provide data for further phylogenetic and comparative studies in peracaridan crustaceans and other arthropods.

Cytotoxicity of different platinum (II) analogues to human tumour cell lines in vitro and murine tumour in vivo alone or combined with electroporation.

BACKGROUND: The in vitro cytotoxic activity of two new platinum(II) complexes (3P-SK and PtAMP) in comparison with cisplatin (CDDP), oxaliplatin (OXA) and carboplatin (CARBO) was determined in four different human tumour cell lines. The in vivo efficiencies of CDDP and 3P-SK in MCA mammary carcinoma tumours induced in CBA mice were compared. MATERIALS AND METHODS: The in vitro cytotoxicity of the platinum (II) complexes was determined by the colorimetric MTT assay. The tumours were treated with different doses of platinum compounds, alone or combined with the local application of electric pulses to the tumour (electrochemotherapy). The antitumour effectiveness was determined by tumour growth inhibition. RESULTS: CDDP and OXA were the most cytotoxic in all cells tested. 3P-SK was more cytotoxic when compared to CARBO in all cells tested, except in MCF7. Intratumoral injection of 3P-SK alone or combined with electroporation (electrochemotherapy) induced significant tumour growth delay and tumour cure. CONCLUSION: 3P-SK was found to be less cytotoxic to human tumour cell lines than CDDP and OXA, but displayed a higher cytotoxicity compared to CARBO. In the experimental tumour model of mammary carcinoma, treatment with 3P-SK, alone or in combination with electroporation, was less effective compared to CDDP, but nevertheless resulted in tumour growth inhibition after a single application.