Examinando por Autor "Velasquez, Luis"

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    Chocolate, Air Pollution and Children's Neuroprotection: What Cognition Tools should be at Hand to Evaluate Interventions?
    (FRONTIERS MEDIA SA, 2016-08) Calderón-Garcidueñas, Lilian; San Juan Chávez, Vanessa; Vacaseydel-Aceves, Nora B.; Calderón-Sánchez, Raymundo; Macías-Escobedo, Edgar; Frías, Carmen; Giacometto, Marcela; Velasquez, Luis; Félix-Villarreal, Renata; Martin, Jessie D.; Draheim, Christopher; Engle, Randall W.
    Millions of children across the world are exposed to multiple sources of indoor and outdoor air pollutants, including high concentrations of fine particulate matter (PM2.5) and ozone (O-3). The established link between exposure to PM2.5, brain structural, volumetric and metabolic changes, severe cognitive deficits (1.5-2 SD from average IQ) in APOE 4 heterozygous females with >75 - <94% BMI percentiles, and the presence of Alzheimer's disease (AD) hallmarks in urban children and young adults necessitates exploration of ways to protect these individuals from the deleterious neural effects of pollution exposure. Emerging research suggests that cocoa interventions may be a viable option for neuroprotection, with evidence suggesting that early cocoa interventions could limit the risk of cognitive and developmental concerns including: endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, and metabolic detrimental brain effects. Currently, however, it is not clear how early we should implement consumption of cocoa to optimize its neuroprotective effects. Moreover, we have yet to identify suitable instruments for evaluating cognitive responses to these interventions in clinically healthy children, teens, and young adults. An approach to guide the selection of cognitive tools should take into account neuropsychological markers of cognitive declines in patients with Alzheimer's neuropathology, the distinct patterns of memory impairment between early and late onset AD, and the key literature associating white matter integrity and poor memory binding performance in cases of asymptomatic familial AD. We highlight potential systemic and neural benefits of cocoa consumption. We also highlight Working Memory Capacity (WMC) and attention control tasks as opened avenues for exploration in the air pollution scenario. Exposures to air pollutants during brain development have serious brain consequences in the short and long term and reliable cognition tools should be at hand to evaluate interventions.
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    Effect of single post-ovulatory administration of mifepristone (RU486) on transcript profile during the receptive period in human endometrium
    (BioScientifica Ltd., 2016-04) Cuevas, Catherina A.; Tapia-Pizarro, Alejandro; Salvatierra, Ana María; Munroe, David J.; Velasquez, Luis; Croxatto, Horacio B.
    Progesterone regulates uterine function during the luteal phase and is essential for the acquisition of endometrial receptivity. The objective of the present study was to identify endometrial transcripts whose expression is altered during the window of implantation after the administration of 200 mg of the antiprogestin mifepristone, 48 h after the LH peak (LHC2, LHC0ZLH peak), and to determine the relationship of these transcripts with those regulated during the acquisition of receptivity. Endometrial samples were obtained in LHC7 from seven women of proven fertility, each one contributing with one cycle treated with placebo and another with mifepristone. Additionally, endometrial samples were obtained in LHC2 and LHC7 during a single untreated spontaneous cycle from seven normal fertile women as a reference. DNA microarrays were used to identify transcripts significantly regulated (defined as R2.0-fold change with false discovery rate below 1% using t-test) with the administration of mifepristone vs placebo, or during the transition from pre-receptive to receptive (LHC2 vs LHC7). Approximately 2000 transcripts were significantly regulated in both comparisons (mifepristone vs placebo and LHC2 vs LHC7), but only 777 of them were coincident and displayed opposite regulation except for 25. The mRNA level for eight selected genes regulated by mifepristone was confirmed by real-time RT-PCR. We conclude that not all changes in endometrial transcript levels occurring in the transition from LHC2 to LHC7 seem to be regulated by the progesterone receptor and w37% of the genes whose transcript levels changed by effect of mifepristone could be associated with the acquisition of receptivity. Reproduction (2016) 151 331–349
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    Mycoplasmateceae species are not found in Fallopian tubes of women with tubo-peritoneal infertility
    (Brazilian Society of Infectious Diseases, 2012) Costoya, Alberto; Morales, Francisco; Borda, Paula; Vargas, Renato; Fuhrer, Juan; Salgado, Nicole; Cárdenas, Hugo; Velasquez, Luis
    BACKGROUND: The role of mycoplasmas on the development and sequelae of pelvic inflammatory disease remains controversial. The objective of the present study is to correlate directly the presence of Mycoplasmateceae through polimerase chain reaction (PCR) determinations in cervix and Fallopian tubes of infertile patients with tubo-peritoneal factor diagnosed through laparoscopy. METHODS: Thirty patients with tubo-peritoneal infertility and 30 normal fertile patients were included in the study; cervical samples and tubal flushings were obtained during laparoscopy. PCR determinations for the detection of genetic material of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealiticum, Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis in cervix and tubal flushings were performed. RESULTS: No Mycoplasmataceae species as "only" microorganisms were found in tubal flushings of tubo-peritoneal infertility patients, whereas three (10%) fertile patients with normal tubes were positive for mycoplasma presence. This difference was not significant (p = 0.237). Among the 30 patients suffering from tubal infertility diagnosed through laparoscopy, Mycoplasmatecae species were not detected in the Fallopian tubes by PCR determinations, while in normal tubes from fertile patients these and other microorganisms could be found without distorting tubal anatomy. CONCLUSION: Mycoplasmateceae species were not detected in Fallopian tubes of women with tubo-peritoneal infertility.
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    Superparamagnetic Poly (3-hydroxybutyrate-co-3 hydroxyvalerate) (PHBV) nanoparticles for biomedical applications
    (Pontificia Universidad Católica de Valparaíso, 2013) Vilos, Cristian; Gutiérrez, Marlen; Escobar, Roberto A.; Morales, Francisco; Denardin, Juliano C.; Velasquez, Luis; Altbir, Dora
    Background: The progress in material science and the recent advances in biodegradable/biocompatible polymers and magnetic iron oxide nanoparticles have led to develop innovative diagnostic and therapeutic strategies for diseases based on multifunctional nanoparticles, which include contrast medium for magnetic resonance imaging, agent for hyperthermia and nanocarriers for targeted drug delivery. The aim of this work is to synthesize and characterize superparamagnetic iron oxide (magnetite), and to encapsulate them into poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles for biomedical applications. Results: The magnetite nanoparticles were confirmed by X-ray diffraction and exhibited a size of 22.3 ± 8.8 nm measured by transmission electron microscopy (TEM). Polymeric PHBV nanoparticles loaded with magnetite (MgNPs) were analyzed using dynamic light scattering and showed a size of 258.6 ± 35.7 nm and a negative zeta potential (-10.8 ± 3.5 mV). The TEM examination of MgNPs exhibited a spherical core-shell structure and the magnetic measurements showed in both, non-encapsulated magnetite and MgNPs, a superparamagnetic performance. Finally, the in vitro studies about the magnetic retention of MgNPs in a segment of small intestine of rats showed an active accumulation in the region of the magnetic field. Conclusions: The results obtained make the MgNPs suitable as potential magnetic resonance imaging contrast agents, also promoting hyperthermia and even as potential nanocarriers for site-specific transport and delivery of drugs. Keywords: hyperthermia, magnetic resonance image (MRI), magnetite, PHBV, polymeric nanoparticles.