Many drugs cannot be administered orally since they cannot be taken up by the intestines. All attempts to solve this problem have thus far resulted in unacceptable risks of side-effects, mainly because the intestinal wall is so severely impacted that not only the drug but other substances, including toxins, can be absorbed. Now a team of scientists from Uppsala University in Sweden have made a major discovery that may solve the problem.
The intestinal wall functions as an effective obstacle to keep various substances from passing from the intestine out into the body. Some drugs, like antibiotics, can use the transport canals that exist, while other important medicines cannot. The porosity of the intestinal wall is determined by a sort of “filter,” so-called “tight junctions,” consisting mainly of two types of proteins: claudins and occludins. Each such protein molecule interacts with a corresponding molecule in the adjacent cell by a loop-shaped bond consisting of peptides. To let more substances pass through, it’s necessary to temporarily increase the porosity of the filter--without damaging the cell. Thus far research has been directed toward changing the porosity via the claudins, which are more dynamic and changeable, but this has always brought with it undesired and irreversible effects that increase the risk of cell damage.
Instead, the Uppsala scientists, led by Professor Per Artursson, have focused on the other protein: the occludins, which are more static proteins. Experiments have been carried out on cells and have yet to be applied to living organisms. They synthesized peptides that correspond to different sequences in the loop that joins the canal between two cells. One of these peptides proved to increase the porosity of the intestinal wall when it was coupled with occludin molecules, but only from one side of the wall. From the other side, corresponding to the one from the intestine out into the body, the molecules proved to lump together or to be destroyed by enzymes before they had time to affect the filter. But the research team went one step further. By adding a fatty acid as a shield for the peptide part, they managed to increase the porosity from the other side as well. What’s more, the scientists succeeded in guiding the effect on the intestinal wall, from rapid and short to a longer lasting impact.
Anneli Waara | alfa
Why might reading make myopic?
18.07.2018 | Universitätsklinikum Tübingen
Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
19.07.2018 | Materials Sciences