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Abstract: The aim of this study is to describe the early stages of spermatogenesis of the Pacific oyster Crassostrea gigas using both light and electron microscopy. The gonad is formed by gonadal tubules invaginated in a connective tissue constituting a storage tissue. Myoepithelial cells surround each gonadal tubule and are associated with an acellular matrix delimiting the outer part of the tubule, the inner part is composed by intragonadal somatic cells associated with germinal lineage. Two types of spermatogonia are identified, where type I spermatogonia (Spg I) are large, scarce and pale cells leaned against the base of the tubule (nuclear diameter: 5.5±0.5μm). Type II spermatogonia (Spg II) are clustered and dark cells which appear smaller than type I (nuclear diameter: 4.3±0.3μm). The aspect of nuage-like material in cytoplasm is described from pale spermatogonia to primary spermatocytes (nuclear diameter: pachytene 3.6±0.3μm, diplotene 3.4±0.3μm), while no structure related to a chromatoid body was observed in oyster spermatocytes and spermatids. [Copyright &y& Elsevier]

Pyridoclax is an original lead, recently identified as very promising in treatment of chemoresistant ovarian cancers. To correct the unfavorable intrinsic physico-chemical properties of this BCS II drug, a formulation strategy was implied in the drug discovery step. Pyridoclax-loaded nanoemulsions (NEs) were developed to permit its preclinical evaluation. The resulting nanoemulsions displayed a mean size of about 100 nm and a high encapsulation efficiency (>95%) at a drug loading of 2 wt%, enabling a 1,000-fold increase of the Pyridoclax apparent solubility. NEs have enabled a sustained release of the drug as assayed by a dialysis bag method. In addition, anti-tumor effects of the Pyridoclax-loaded nanoemulsions (PNEs) showed a 2.5-fold higher activity on chemoresistant ovarian cancer cells than free Pyridoclax. This effect was confirmed by a drastic increase of caspase 3/7 activation from 10 µM PNEs, as newly objectified by real time apoptose imaging. The Pyridoclax bioavailability was kept unchanged after encapsulation in nanoemulsions as determined in a mice model after oral administration. Thus, NEs should permit valuable Pyridoclax oral administration, and valorization of this promising anticancer drug by maintaining its original anticancer activity, and by reducing the Pyridoclax therapeutic concentration. [ABSTRACT FROM AUTHOR]