MDCK cells (epithelioid of renal origin) form monolayers which are structurally and functionally similar to transporting epithelia. One of these similarities is the ability to form occluding junctions and act as permeability barriers. This article studies the junctions of MDCK monolayers formed on a permeable and transparent support (a disk of nylon cloth coated with collagen) by combining two different approaches: (i) Scanning of the electric field: the disk is mounted as a flat sheet between two Lucite chambers and pulses of 20--50 microA cm-2 are passed across. The apical surface of the monolayer is then scanned with a microelectrode to detect those points where the current is flowing. This shows that the occluding junctions of this preparation are not homogeneous, but contain long segments of high resistance, intercalated with sites of high conductance. (ii) Freeze fracture electron microscopy: the junctions are composed of regions of eight to ten strands intercalated with others where the strands are reduced to one or two ridges. The sites of high conductance may correspond to those segments where the number of junctional strands is reduced to 1 or 2. It is concluded that the occluding junctions of MDCK monolayers are functionally and morphologically heterogeneous, with "tight" regions intermixed with "leaky" ones.

No abstract

This Viewpoint discusses the World Health Organization's Declaration on 1 February 2016 that the epidemic infection caused by the Zika virus is a public health emergency of international concern - the basis of the decision and controversy surrounding it.

auto injector and the use of documents related with corporal mass and biotype patients. Results: All the patients learned the techniques and performed the auto injection without problems. These patients showed clinical improvement confirmed by MRI. Conclusions: Our results demonstrated that it is possible to educate patients how to perform injections at different sites. This guarantees adequate administration of the drug and contributes to the clinical improvement of the patients.