Hypothyroidism provides resistance to kidney mitochondria against the injury induced by renal ischemia-reperfusion

Massive Ca(2+) accumulation in mitochondria, plus the stimulating effect of an inducing agent, i.e., oxidative stress, induces the so-called permeability transition, which is characterized by the opening of a nonspecific pore. This work was aimed at studying the influence of thyroid hormone on the opening of such a nonspecific pore in kidney mitochondria, as induced by an oxidative stress. To meet this objective, membrane permeability transition was examined in mitochondria isolated from kidney of euthyroid and hypothyroid rats, after a period of ischemia/reperfusion. It was found that mitochondria from hypothyroid rats were able to retain accumulated Ca(2+) to sustain a transmembrane potential after Ca(2+) addition, as well as to maintain matrix NAD(+) and membrane cytochrome c content. The protective effect of hypothyroidism was clearly opposed to that occurring in ischemic reperfused mitochondria from euthyroid rats. Our findings demonstrate that these mitochondria were unable to preserve selective membrane permeability, except when cyclosporin A was added. It is proposed that the protection is conferred by the low content of cardiolipin found in the inner membrane. This phospholipid is required to switch adenine nucleotide translocase from specific carrier to a non-specific pore.     

Synthesis and potent antitumor activity of new arylamino derivatives of nor-beta-lapachone and nor-alpha-lapachone

Several arylamino derivatives of nor-beta-lapachone were synthesized in moderate to high yields and found to show very potent cytotoxicity against six neoplastic cancer cells: SF-295 (central nervous system), HCT-8 (colon), MDAMB-435 (breast), HL-60 (leukaemia), PC-3 (prostate), and B-16 (murine melanoma), with IC(50) below 1 microg/mL. Their cytotoxicities were compared to doxorubicin and with their synthetic precursors, beta-lapachone and nor-beta-lapachone. The activity against a normal murine fibroblast L-929 showed that some of the compounds were selective against cancer cells. The absence of hemolytic activity (EC(50)>200 microg/mL), performed with erythrocyte suspensions, suggests that the cytotoxicity of the compounds was not related to membrane damage of mouse erythrocytes. For comparison purposes, one isomeric compound based on nor-alpha-lapachone was also synthesized and showed lower activity than the related ortho-derivative. The modified arylamino quinones appear as interesting new lead compounds in anti-cancer drug development.     

Palmitoylation of inducible nitric-oxide synthase at Cys-3 is required for proper intracellular traffic and nitric oxide synthesis

A number of cell types express inducible nitric-oxide synthase (NOS2) in response to exogenous insults such as bacterial lipopolysaccharide or proinflammatory cytokines. Although it has been known for some time that the N-terminal end of NOS2 suffers a post-translational modification, its exact identification has remained elusive. Using radioactive fatty acids, we show herein that NOS2 becomes thioacylated at Cys-3 with palmitic acid. Site-directed mutagenesis of this single residue results in the absence of the radiolabel incorporation. Acylation of NOS2 is completely indispensable for intracellular sorting and .NO synthesis. In fact, a C3S mutant of NOS2 is completely inactive and accumulates to intracellular membranes that almost totally co-localize with the Golgi marker beta-cop. Likewise, low concentrations of the palmitoylation blocking agents 2-Br-palmitate or 8-Br-palmitate severely affected the .NO synthesis of both NOS2 induced in muscular myotubes and transfected NOS2. However, unlike endothelial NOS, palmitoylation of inducible NOS is not involved in its targeting to caveolae. We have created 16 NOS2-GFP chimeras to inspect the effect of the neighboring residues of Cys-3 on the degree of palmitoylation. In this regard, the hydrophobic residue Pro-4 and the basic residue Lys-6 seem to be indispensable for palmitoylation. In addition, agents that block the endoplasmic reticulum to Golgi transit such as brefeldin A and monensin drastically reduced NOS2 activity leading to its accumulation in perinuclear areas. In summary, palmitoylation of NOS2 at Cys-3 is required for both its activity and proper intracellular localization.     

DNA damage in peripheral blood lymphocytes in patients during combined chemotherapy for breast cancer

Combined chemotherapy is used for the treatment of a number of malignancies such as breast cancer. The target of these antineoplastic agents is nuclear DNA, although it is not restricted to malignant cells. The aim of the present study was to assess DNA damage in peripheral blood lymphocytes (PBLs) of breast cancer patients subjected to combined adjuvant chemotherapy (5-fluorouracil, epirubicin and cyclophosphamide, FEC), using a modified comet assay to detect DNA single-strand breaks (SSB) and double-strand breaks (DSB).

Forty-one female patients with advanced breast cancer before and after chemotherapy and 60 healthy females participated in the study. Alkaline and neutral comet assays were performed in PBLs according to a standard protocol, and DNA tail moment was measured by a computer-based image analysis system.

Breast cancer patients before treatment had higher increased background levels of SSB and DSB as compared to healthy women. During treatment, a significant increase in DNA damage was observed after the 2nd cycle, which persisted until the end of treatment. Eighty days after the end of treatment the percentage of PBLs with SSB and DSB remained elevated, but the magnitude of DNA damage (tail moment) returned to baseline levels. There was no correlation between PBL DNA damage and response to chemotherapy.

DNA-SSB and DSB in PBLs are present in cancer patients before treatment and increase significantly after combined chemotherapy. No correlation with response to adjuvant chemotherapy was found. Biomonitoring DNA damage in PBLs of cancer patients could help prevent secondary effects and the potential risks of developing secondary cancers.     

Cognitive impairment and the risk of falling in the elderly

Risk of fall is significantly increased in old people with cognitive decline due to specific associations between gait parameters and cognition. This association has recently been demonstrated, there being increasing evidence that cognitive domains such as attention, executive function and types of memory are critical for the correct regulation of gait. Gait disturbances can appear as early predictors of dementia in elderly patients. In the assessment of the fall risk, the use of dual tasks is novel, simple and relevant, especially in cognitive decline. Evidence for interventions in this population is limited, with vitamin D and physical exercise being the most encouraging, for decreasing the risk of fall in dementia.     

Synthesis, characterization and antiproliferative studies of the enantiomers of cis-[(1,2-camphordiamine)dichloro]platinum(II) complexes

The platinum(II) complex cis-[(1S,2R,3S)-1,7,7-trimethylbicyclo[2.2.1]heptane-2,3-diamine]dichloroplatinum(II) (1) and its enantiomer (2) have been synthesized and physically and spectroscopically characterized. To obtain the enantiopure complexes the chiral pool approach was applied. The synthetic pathway has four steps, starting from (+/-)-diphenylethylenediamine (DPEDA) (3) and the natural products (1S)-camphorquinone or (1R)-camphorquinone to obtain enantiomers 1 and 2, respectively. The interaction of the Pt(II) complexes with DNA was studied by several techniques: circular dichroism, electrophoresis on agarose gel and atomic force microscopy (AFM). These studies showed differences in the degree of interaction between both enantiomers and DNA (calf thymus DNA and plasmid pBR322 DNA). The cytotoxicity of enantiomers 1 and 2 against the HL-60 cell line was studied by in vitro tests of antiproliferative activity, incubating during both 24 h and 72 h. An important difference of activity was found between both enantiomers regarding the IC50 data at 24 h of incubation. Thus, complex 1 showed to be much more active than its enantiomer 2.     

Differentiation of Human Umbilical Cord Matrix Mesenchymal Stem Cells into Neural-Like Progenitor Cells and Maturation into an Oligodendroglial-Like Lineage

Mesenchymal stem cells (MSCs) are viewed as safe, readily available and promising adult stem cells, which are currently used in several clinical trials. Additionally, their soluble-factor secretion and multi-lineage differentiation capacities place MSCs in the forefront of stem cell types with expected near-future clinical applications. In the present work MSCs were isolated from the umbilical cord matrix (Wharton''s jelly) of human umbilical cord samples. The cells were thoroughly characterized and confirmed as bona-fide MSCs, presenting in vitro low generation time, high proliferative and colony-forming unit-fibroblast (CFU-F) capacity, typical MSC immunophenotype and osteogenic, chondrogenic and adipogenic differentiation capacity. The cells were additionally subjected to an oligodendroglial-oriented step-wise differentiation protocol in order to test their neural- and oligodendroglial-like differentiation capacity. The results confirmed the neural-like plasticity of MSCs, and suggested that the cells presented an oligodendroglial-like phenotype throughout the differentiation protocol, in several aspects sharing characteristics common to those of bona-fide oligodendrocyte precursor cells and differentiated oligodendrocytes.     

Learning Probabilistic Features for Robotic Navigation Using Laser Sensors

SLAM is a popular task used by robots and autonomous vehicles to build a map of an unknown environment and, at the same time, to determine their location within the map. This paper describes a SLAM-based, probabilistic robotic system able to learn the essential features of different parts of its environment. Some previous SLAM implementations had computational complexities ranging from O(Nlog(N)) to O(N²), where N is the number of map features. Unlike these methods, our approach reduces the computational complexity to O(N) by using a model to fuse the information from the sensors after applying the Bayesian paradigm. Once the training process is completed, the robot identifies and locates those areas that potentially match the sections that have been previously learned. After the training, the robot navigates and extracts a three-dimensional map of the environment using a single laser sensor. Thus, it perceives different sections of its world. In addition, in order to make our system able to be used in a low-cost robot, low-complexity algorithms that can be easily implemented on embedded processors or microcontrollers are used.