Kinetics and thermodynamics of irreversible inhibition of matrix metalloproteinase?2 by a Co(III) Schiff base complex

Cobalt(III) Schiff base complexes have been used as potent inhibitors of protein function through the coordination to histidine residues essential for activity. The kinetics and thermodynamics of the binding mechanism of Co(acacen)(NH(3))(2)Cl [Co(acacen); where H(2)acacen?is?bis(acetylacetone)ethylenediimine] enzyme inhibition has been examined through the inactivation of matrix metalloproteinase?2 (MMP-2) protease activity. Co(acacen) is an irreversible inhibitor that exhibits time- and concentration-dependent inactivation of MMP-2. Co(acacen) inhibition of MMP-2 is temperature-dependent, with the inactivation increasing with temperature. Examination of the formation of the transition state for the MMP-2/Co(acacen) complex was determined to have a positive entropy component indicative of greater disorder in the MMP-2/Co(acacen) complex than in the reactants. With further insight into the mechanism of Co(acacen) complexes, Co(III) Schiff base complex protein inactivators can be designed to include features regulating activity and protein specificity. This approach is widely applicable to protein targets that have been identified to have clinical significance, including matrix metalloproteinases. The mechanistic information elucidated here further emphasizes the versatility and utility of Co(III) Schiff base complexes as customizable protein inhibitors.     

Variegated silencing through epigenetic modifications of a large Xq region in a case of balanced X;2 translocation with Incontinentia Pigmenti-like phenotype

Molecular mechanisms underlying aberrant phenotypes in balanced X;autosome translocations are scarcely understood. We report the case of a de novo reciprocal balanced translocation X;2(q23;q33) presenting phenotypic alterations highly suggestive of Incontinentia Pigmenti (IP) syndrome, a genodermatosis with abnormal skin pigmentation and neurological failure, segregating as X-linked dominant disorder. Through molecular studies, we demonstrated that the altered phenotype could not be ascribed to chromosome microdeletions or to XIST-mediated inactivation of Xq24-qter. Interestingly, we found that the Xq24-qter region, which translocated downstream of the heterochromatic band 2q34, undergoes epigenetic silencing mediated by DNA methylation and histone alterations. Among the downregulated genes, we found the inhibitor of kappa light polypeptide gene enhancer in B cells, kinase gamma (IKBKG/NEMO), the causative gene of IP. We hypothesize that a mosaic functional nullisomy of the translocated genes, through a Position Effect Variegation-like heterochromatization, might be responsible for the proband's phenotypic anomalies. Partial silencing of IKBKG may be responsible for the skin anomalies observed, thereby mimicking the IP pathological condition. In addition to its clinical relevance, this paper addresses fundamental issues related to the chromatin status and nuclear localization of a human euchromatic region translocated proximally to heterochromatin. In conclusion, the study provides new insight into long-range gene silencing mechanisms and their direct impact in human disease.     

Metabolic profiling of human CD4+ cells following treatment with methotrexate and anti-TNF-α infliximab

The autoimmune process in rheumatoid arthritis depends on activation of immune cells, which utilize intracellular kinases to respond to external stimuli such as cytokines, immune complexes, and antigens. CD4+ T cells comprise a large proportion of the inflammatory cells that invade the synovial tissue and may therefore be a cell type of pathogenic importance. Both methotrexate and infliximab are effective in the treatment of inflammatory arthritis; however, the biological effects triggered by these treatments and the biochemical mechanisms underlining the cell response are still not fully understood. Thus, in this study the global metabolic changes associated with methotrexate or infliximab treatment of isolated human CD4+ T cells were examined using gas chromatography/mass spectrometry or liquid chromatography/mass spectrometry. In total 148 metabolites involved in selective pathways were found to be significantly altered. Overall, the changes observed are likely to reflect the effort of CD4+ cells to increase the production of cellular reducing power to offset the cellular stress exerted by treatment. Importantly, analysis of the global metabolic changes associated with MTX or infliximab treatment of isolated human CD4+ T cells suggested that the toxicity associated with these agents is minimal when used at clinically relevant concentrations.     

Intraoperative radiation therapy,opportunities for clinical practice normalization: MEDTING,a scientific platform

Aim

To use a platform to analyze a subgroup specialized in evaluation of patients candidates to IOERT.

Background

Medting is a project that was initiated to support daily clinical activity, knowledge management and medical education by sharing information with other physicians. The project began at the “Hospital General Universitario Gregorio Marañón”, which has a dedicated oncology physician''s multi-specialist committee. There are many scientific social networks all over the world. Medting is the only platform that specializes in healthcare and has been developed for hospital purposes.

Materials and methods

Medting brings all together the relevant clinical information from electronic medical records and picture archiving about the patient to study. Subplatform Medting-IORT was created on February 2, 2012 at the Hospital General Universitario Gregorio Marañon. It has 23 members, have been registered 18 cases with 238 multimedia images.

Results

Medting started with 28 physicians and five departments. After 6 months, proof of concept period, there are 225 physicians, more than 120 medical students and 39 departments in 3 hospitals using the scientific social network. Furthermore, the project is being extended on three more hospitals in Madrid.

Conclusion

Medting gives the opportunity to oncology physicians to access all relevant clinical information with the ability to discuss case notes and view images at any time. The impact of the Medting platform in a subgroup working team to evaluate IOERT patients candidates is included in the analysis. The use of a constantly updated repository based on real cases and the documentation of the internal activity of the tumor committee beyond the medical record, has become an extraordinary tool for teaching, training and learning.     

Affinities of the Canthonini dung beetles of the Eastern Arc Mountains

The Eastern Arc Mountains (EAM) consist of 13 separate mountain blocks running from southern Kenya through eastern Tanzania in an arc shape. Organisms occurring in the forests of these mountains are known for their high levels of endemism. Some of these organisms have their closest relatives in distant geographic regions. In this study, molecular phylogenetic methods, based on partial sequences of one nuclear (28S) and two mitochondrial (COI and 16S) genes, are used to determine the relationships of three Scarabaeinae genera (tribe Canthonini) endemic to the EAM. Janssensantus and Tanzanolus are found to have a sister relationship within a lineage of south-eastern African genera, while Madaphacosoma’s closest ties are with Oriental and Madagascan taxa Ochicanthon and Epactoides, respectively. Divergence time estimates suggest a Miocene origin for the ancestral lineages of the three genera with Janssensantus and Tanzanolus separating in the Pleistocene. Our results provide evidence for a Madagascan origin for the EAM genera.