Characterization of a new extra-axonemal structure in the Giardia intestinalis flagella

The inner structure of the flagella of Giardia intestinalis is similar to that of other organisms, consisting of nine pairs of outer microtubules and a central pair containing radial spokes. Although the 9+2 axonemal structure is conserved, it is not clear whether subregions, including the transition zone, are present in the flagella of this parasite. Giardia axonemes originate from basal bodies and have a lengthy cytosolic portion before becoming active flagella. The region of the emergence of the flagellum is not accompanied by any membrane specialization, as seen in other protozoa. Although Giardia is an intriguing model of study, few works focused on the ultrastructural analysis of the flagella of this parasite. Here, we analyzed the externalization region of the G. intestinalis flagella using ultra-high resolution scanning microscopy (with electrons and ions), atomic force microscopy in liquid medium, freeze fracture, and electron tomography. Our data show that this region possesses a distinctive morphological feature - it extends outward and takes on a ring-like shape. When the plasma membrane is removed, a structure surrounding the axoneme becomes visible in this region. This new extra-axonemal structure is observed in all pairs of flagella of trophozoites and remains attached to the axoneme even when the interconnections between the axonemal microtubules are disrupted. High-resolution scanning electron microscopy provided insights into the arrangement of this structure, contributing to the characterization of the externalization region of the flagella of this parasite.

Mechanical properties of polypropylene mesh used in pelvic floor repair

The aim of this study was the comparison of the stiffness of different meshes under two types of mechanical tests. Five different mesh types were mechanically tested. The methods used consisted on uniaxial tension test (tensile stiffness) and tape ring tests, experimental continuous compression of the mesh loops (flexural stiffness). The most significant difference of tensile stiffness behaviour appears between Aris and TVTO. From the analysis of the experimental data, we divided the flexural stiffness, in two main groups. The first group includes Auto Suture and Aris meshes. The two meshes seem to have a similar flexural behaviour. The second group includes TVTO, Uretex and Avaulta. The difference between these two groups is clearly evident comparing TVTO and Aris. This study shows that there are significant differences on the mechanical properties between urogynecology meshes.

[Estrogen and progesterone receptors in the human placenta]

The author demonstrates the presence of estrogen and progesterone receptors in the trophoblast. He also refers to their distribution within the cytosol and the nucleus, and also discusses their diversity in the various parts of the placenta. He did not detect any difference between placentas obtained from normal deliveries and those obtained after cesarean deliveries.