Faecal microbiota transplantation-A clinical view

Faecal microbiota transplantation has gained increasing attention over the last decade as various phenotypes could be transferred from a donor to a recipient in different animal models. Clinically, however, the sole indication with evidence from a randomized placebo controlled trial is refractory Clostridium difficile infection. Despite revealing successful clinical outcomes, questions concerning regulatory affairs, the identification of the best donor, the optimal mixture of the transplant as well as the preferred route of administration remain to be clarified even for this indication. Initiated by the idea that alterations in the composition of the intestinal microbiota are associated with intestinal inflammation in inflammatory bowel disease, several studies investigated whether faecal microbiota transplantation would be an equally suitable approach for these devastating disorders. Indeed, the available data indicate changes in the microbiota composition following faecal microbial transplantation depending on the degree of intestinal inflammation. Furthermore, first data even provide evidence that the transplantation of an "optimized" microbiota induces clinical remission in ulcerative colitis. However, despite these intriguing results it needs to be considered that not only "a cure of inflammation", but also risk factors and phenotypes including obesity can be transferred via faecal microbiota transplantation. Thus, a deeper understanding of the impact of a distinct microbiota composition is required before "designing" the optimal faecal microbiota transplant.

Regulation of type 2 nitric oxide synthase by type 1 interferons in macrophages infected with Leishmania major

We recently reported that the infection of macrophages with Leishmania major led to the release of type 1 interferons (IFN-alpha /beta ). Moreover, at day 1 of infection of mice with L. major, IFN-alpha /beta was required for the expression of type 2 (inducible) NO synthase (NOS2 or iNOS) which, however, was restricted to a few macrophages in the dermis. Here, we further characterized the regulation of NOS2 by IFN-alpha /beta. Macrophages that were either simultaneously or sequentially exposed to L. major promastigotes and IFN-alpha /beta expressed NOS2 and anti-leishmanial activity. In contrast, when high amounts of IFN-alpha /beta were used or when IFN-alpha /beta was added to the macrophages 2 h prior to the parasites, almost no induction of NOS2 was observed. After pretreatment with IFN-alpha /beta, tyrosine phosphorylation and nuclear DNA binding of Stat1alpha, the degradation of the NF-kappaB inhibitor (IkappaBalpha and beta), and the nuclear translocation of NF-kappaB were strongly impaired compared with macrophages exposed to IFN-alpha /beta and L. major simultaneously. Thus, IFN-alpha /beta exerts agonistic or antagonistic effects on the expression of NOS2 in macrophages infected with a microbial pathogen, depending on the sequence of the stimuli and the amount of IFN-alpha /beta added. The limited number of NOS2-positive macrophages at day 1 of infection in vivo might result from a blockage of non-infected macrophages by IFN-alpha /beta that is released by neighboring infected cells.

Non-invasive temperature mapping using MRI: comparison of two methods based on chemical shift and T1-relaxation

PURPOSE

To implement and evaluate the accuracy of non-invasive temperature mapping using MRI methods based on the chemical shift (CS) and T1 relaxation in media of various heterogeneity during focal (laser) and external thermal energy deposition.

MATERIALS AND METHODS

All measurements were performed on a 1.5 T superconducting clinical scanner using the temperature dependence of the water proton chemical shift and the T1 relaxation time. Homogeneous gel and heterogeneous muscle phantoms were heated focally with a fiberoptic laser probe and externally of varying degree ex vivo by water circulating in a temperature range of 20-50 degrees C. Magnetic resonance imaging data were compared to simultaneously recorded fiberoptic temperature readings.

RESULTS

Both methods provided accurate results in homogeneous media (turkey) with better accuracy for the chemical shift method (CS:+/-1.5 degrees C, T1:+/-2.0 degrees C). In gel, the accuracy with the CS method was +/-0.6 degrees C. The accuracy decreased in heterogeneous media containing fat (T1:+/-3.5 degrees C, CS: +5 degrees C). In focal heating of turkey muscle, the accuracy was within 1.5 degrees C with the T1 method.

CONCLUSION

Temperature monitoring with the chemical shift provides better results in homogeneous media containing no fat. In fat tissue, the temperature calculation proved to be difficult.