Salazar Vazquez B.Y.,Universidad Juarez del Estado de Durango |
Martini J.,Innsbruck Medical University |
Chavez Negrete A.,Instituto Mexicano Of Seguro Social |
Tsai A.G.,University of California at San Diego |
And 4 more authors.
Clinical Hemorheology and Microcirculation | Year: 2010
Decreasing blood viscosity has been proposed since the advent of hemodilution as a means for increasing perfusion in many pathological conditions, and increased plasma viscosity is associated with the presence of pathological conditions. However, experimental studies show that microvascular functions as represented by functional capillary density in conditions of significantly decreased viscosity is impaired, a problem corrected by increasing plasma and blood viscosity. Blood viscosity, primarily dependent on hematocrit (Hct) is a determinant of peripheral vascular resistance, and therefore blood pressure. In the healthy population Hct presents a variability, which is not reflected by the variability of blood pressure. This is due to a regulatory process at the level of the endothelium, whereby the increase of Hct (and therefore blood viscosity) leads to increased shear stress and the production of the vasodilator nitric oxide (NO), a finding supported by experimental studies showing that the acute increase of Hct lowers blood pressure. Studies that in the healthy population show that blood pressure and Hct have a weak positive correlation. However, when the effect of blood viscosity is factored out, blood pressure and Hct are negatively and significantly correlated, indicating that as blood viscosity increases, the circulation dilates. Conversely, lower Hct and blood viscosity conditions lead to a constricted circulation, associated with a condition of decreased NO bioavailability, and therefore a pro-inflammatory condition. © 2010-IOS Press and the authors. All rights reserved.
Ramirez-Ortiz M.A.,Hospital Infantil de Mexico Federico Gomez |
Ponce-Castaneda M.V.,Instituto Mexicano Of Seguro Social |
Cabrera-Munoz M.L.,Hospital Infantil de Mexico Federico Gomez |
Medina-Sanson A.,Hospital Infantil de Mexico Federico Gomez |
And 2 more authors.
Cancer Epidemiology Biomarkers and Prevention | Year: 2014
Background: More invasive retinoblastoma, characterized by increased morbidity and mortality, with lower rates of eye salvage and higher rates of extraocular dissemination, seems more prevalent in resource-poor countries. The relationship of diagnostic delay (lag time) and sociodemographic factors on the extent of disease at diagnosis has not been examined separately for unilateral and bilateral retinoblastoma. Methods: At diagnosis, consenting parents of 179 Mexican children with retinoblastoma were interviewed about initial symptoms and household demographic characteristics. Clinical presentation was classified using St. Jude's, International Staging System (ISS), and International Intraocular Retinoblastoma Classification (IIRC) criteria. Lag time (delay between noting symptoms and diagnosis) and sociodemographic factors were examined as predictors for higher stage at diagnosis and overall survival (OS). Results: In bilateral disease, lag time predicts stage at diagnosis using St. Jude's, and ISS criteria (P < 0.005 in multivariate regression), and OS (P < 0.05, Cox hazards), but not extent of intraocular disease (by IIRC). In unilateral disease, lag time predicts neither extent of disease (using ISS, St Jude's, and IIRC), nor OS. Indicators of prenatal poverty, including lower maternal education and the presence of dirt flooring in the home, predict more advanced disease by IIRC for bilateral retinoblastoma, and for unilateral by ISS, and St Jude's (P < 0.001) as well as OS (P < 0.05). Conclusion: These results suggest unilateral and bilateral retinoblastoma differs in factors governing progression and extraretinal extension, possibly reflecting underlying biologic heterogeneity. Impact: This demonstrates differing effect of social factors on extent of intra- and extraocular disease depending on laterality with implications for screening strategies. © 2014 American Association for Cancer Research.
Belinson J.L.,Cleveland Clinic |
Salmeron J.,Instituto Mexicano Of Seguro Social
International Journal of Cancer | Year: 2011
Even in the era of highly effective human papillomavirus (HPV) prophylactic vaccines, substantial reduction in worldwide cervical cancer mortality will only be realized if effective early detection and treatment of the millions of women already infected and the millions who may not receive vaccination in the next decade can be broadly implemented through sustainable cervical cancer screening programs. Effective programs must meet three targets: (i) at least 70% of the targeted population should be screened at least once in a lifetime, (ii) screening assays and diagnostic tests must be reproducible and sufficiently sensitive and specific for the detection of high-grade precursor lesions (i.e., CIN2+), and (iii) effective treatment must be provided. We review the evidence that HPV DNA screening from swabs collected by the women in their home or village is sufficiently sound for consideration as a primary screening strategy in the developing world, with sensitivity and specificity for detection of CIN2+ as good or better than Pap smear cytology and VIA. A key feature of a self-collected HPV testing strategy (SC-HPV) is the move of the primary screening activities from the clinic to the community. Efforts to increase the affordability and availability of HPV DNA tests, community education and awareness, development of strong partnerships between community advocacy groups, health care centers and regional or local laboratories, and resource appropriate strategies to identify and treat screen-positive women should now be prioritized to ensure successful public health translation of the technologic advancements in cervical cancer prevention. Copyright © 2011 UICC.
Jauregui-Renaud K.,Instituto Mexicano del Seguro Social |
Cruz-Gomez N.S.,Instituto Mexicano del Seguro Social |
Villanueva-Padron L.A.,Instituto Mexicano Of Seguro Social
Archives of Medical Research | Year: 2013
Background and Aims: We undertook this study to estimate the limits of agreement of repeated measures of static posturography on healthy adults and to assess the use of those limits on the interpretation of variations observed during vestibular rehabilitation of patients with chronic, peripheral vestibular disease. Methods: Twenty healthy adults and 30 vestibular patients accepted to participate. At baseline and at weeks 4, 6 and 8 of follow-up, posturography was performed with the eyes open or closed, while adding or not a layer of foam rubber to the base of support. The Dizziness Handicap Inventory was administered to patients prior to rehabilitation and at week 8. Results: At baseline, a difference between groups was observed on the sway area (. p < 0.05). Healthy subjects showed no statistical difference among the four recordings (repeatability of measurements from 85-100%). Vestibular patients showed differences among the four recordings on the area and the length/average speed of sway (. p <0.05); individual differences from baseline exceeding the limits of agreement were observed on the sway area. A decrease on the Dizziness Handicap Inventory (≥18 points) was observed on 19 patients, from whom 12 (63, 95% CI 53-73%) showed a change on the sway area (eyes closed) that was larger than the limits of agreement. Conclusions: In healthy subjects, intra-subject repeated recordings of the area and the length/average speed of sway may be reliable at intervals of 4, 6 and 8 weeks. The sway area (without vision) may be a useful sway component, among others, to follow-up vestibular patients with chronic, peripheral disease during rehabilitation. © 2013 IMSS.
Pineda A.,Instituto Mexicano Of Seguro Social |
Verdin-Teran S.L.,National Autonomous University of Mexico |
Camacho A.,Instituto Mexicano Of Seguro Social |
Moreno-Fierros L.,National Autonomous University of Mexico
Archives of Medical Research | Year: 2011
Background and Aims: Few studies have examined the presence of Toll-like receptors (TLRs) in term placentas from women with preeclampsia, such, have focused on TLR-4 and TLR-2 analysis. Whereas an increase in TLR-4 immunostaining has been observed in preeclampsia, it is even higher in placentas with chorioamnionitis compared with normal pregnancy. Expression of TLR-2 has not been associated with preeclampsia. The relationship of TLR-3 and TLR-9, which may recognize dsRNA or DNA, either derived either from microorganisms or from apoptotic cells and thus may be involved with this pathology, has not been studied in term placentas. We undertook this study to determine if there are changes in the expression and localization of TLR-2, TLR-4, TLR-3 and TLR-9 in preeclamptic term placentas as compared with normal placentas. Methods: A prospective, cross-sectional and comparative study was done in a group of ten patients with 38-40 gestation weeks, both in preeclamptic and control cases. Immunofluorescence detection of TLRs was performed in samples of placenta and analyzed by confocal microscopy. Results: It was observed that TLR-2, TLR-3, TLR-4 and TLR-9 were expressed both in normal and preeclamptic placentas, in the trophoblast, at the vascular endothelium (where TLR-2 and TLR-9 staining was pronounced), and at placental villous stroma, although increased expression was detected in preeclampsia. In addition, co-localization of TLR-2 and TLR-4 as well as of TLR-3 and TL9 was found in the trophoblast. Conclusions: TLR-2, -3, -4 and -9 expressions are increased in preeclamptic placentas. However, more studies are required to determine the role of TLRs in pregnancy immunology and to establish its relationship with preeclampsia. © 2011 IMSS.