Instituto Politécnico Nacional

About: Instituto Politécnico Nacional is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Population & Context (language use). The organization has 43351 authors who have published 63315 publications receiving 938532 citations. The organization is also known as: Instituto Politécnico Nacional & Instituto Politecnico Nacional.

Tetracyclines: a pleitropic family of compounds with promising therapeutic properties. Review of the literature

Abstract: There must be something unique about a class of drugs (discovered and developed in the mid-1940s) where there are more than 130 ongoing clinical trials currently listed. Tetracyclines were developed as a result of the screening of soil samples for antibiotic organisms. The first of these compounds chlortetracycline was introduced in 1948. Soon after their development tetracyclines were found to be highly effective against various pathogens including rickettsiae, Gram-positive, and Gram-negative bacteria, thus, becoming a class of broad-spectrum antibiotics. The mechanism of action of tetracyclines is thought to be related to the inhibition of protein synthesis by binding to the 30S bacterial ribosome. Tetracyclines are also an effective anti-malarial drug. Over time, many other "protective" actions have been described for tetracyclines. Minocycline, which can readily cross cell membranes, is known to be a potent anti-apoptotic agent. Its mechanism of action appears to relate to specific effects exerted on apoptosis signaling pathways. Another tetracycline, doxycycline is known to exert antiprotease activities. Doxycycline can inhibit matrix metalloproteinases, which contribute to tissue destruction activities in diseases such as gingivitis. A large body of literature has provided additional evidence for the "beneficial" actions of tetracyclines, including their ability to act as oxygen radical scavengers and anti-inflammatory agents. This increasing volume of published work and ongoing clinical trials supports the notion that a more systematic examination of their possible therapeutic uses is warranted. This review provides a summary of tetracycline's multiple mechanisms of action and while using the effects on the heart as an example, this review also notes their potential to benefit patients suffering from various pathologies such as cancer, Rosacea, and Parkinson's disease.

Effect of Colchicine vs Standard Care on Cardiac and Inflammatory Biomarkers and Clinical Outcomes in Patients Hospitalized With Coronavirus Disease 2019: The GRECCO-19 Randomized Clinical Trial.

Abstract: Importance Severe acute respiratory syndrome coronavirus 2 infection has evolved into a global pandemic Low-dose colchicine combines anti-inflammatory action with a favorable safety profile Objective To evaluate the effect of treatment with colchicine on cardiac and inflammatory biomarkers and clinical outcomes in patients hospitalized with coronavirus disease 2019 (COVID-19) Design, Setting, and Participants In this prospective, open-label, randomized clinical trial (the Greek Study in the Effects of Colchicine in COVID-19 Complications Prevention), 105 patients hospitalized with COVID-19 were randomized in a 1:1 allocation from April 3 to April 27, 2020, to either standard medical treatment or colchicine with standard medical treatment The study took place in 16 tertiary hospitals in Greece Intervention Colchicine administration (15-mg loading dose followed by 05 mg after 60 min and maintenance doses of 05 mg twice daily) with standard medical treatment for as long as 3 weeks Main Outcomes and Measures Primary end points were (1) maximum high-sensitivity cardiac troponin level; (2) time for C-reactive protein to reach more than 3 times the upper reference limit; and (3) time to deterioration by 2 points on a 7-grade clinical status scale, ranging from able to resume normal activities to death Secondary end points were (1) the percentage of participants requiring mechanical ventilation, (2) all-cause mortality, and (3) number, type, severity, and seriousness of adverse events The primary efficacy analysis was performed on an intention-to-treat basis Results A total of 105 patients were evaluated (61 [581%] men; median [interquartile range] age, 64 [54-76] years) with 50 (476%) randomized to the control group and 55 (524%) to the colchicine group Median (interquartile range) peak high-sensitivity cardiac troponin values were 00112 (00043-00093) ng/mL in the control group and 0008 (0004-00135) ng/mL in the colchicine group (P = 34) Median (interquartile range) maximum C-reactive protein levels were 45 (14-89) mg/dL vs 31 (08-98) mg/dL (P = 73), respectively The clinical primary end point rate was 140% in the control group (7 of 50 patients) and 18% in the colchicine group (1 of 55 patients) (odds ratio, 011; 95% CI, 001-096;P = 02) Mean (SD) event-free survival time was 186 (083) days the in the control group vs 207 (031) in the colchicine group (log rankP = 03) Adverse events were similar in the 2 groups, except for diarrhea, which was more frequent with colchicine group than the control group (25 patients [455%] vs 9 patients [180%];P = 003) Conclusions and Relevance In this randomized clinical trial, participants who received colchicine had statistically significantly improved time to clinical deterioration There were no significant differences in high-sensitivity cardiac troponin or C-reactive protein levels These findings should be interpreted with caution Trial Registration ClinicalTrialsgov Identifier:NCT04326790

Phosphate starvation induces a determinate developmental program in the roots of Arabidopsis thaliana.

Abstract: When growing under limiting phosphate (P) conditions, Arabidopsis thaliana plants show dramatic changes in root architecture, including a reduction in primary root length, increased formation of lateral roots and greater formation of root hairs. Here we report that primary root growth inhibition by low P is caused by a shift from an indeterminate to a determinate developmental program. In the primary root, the low P-induced determinate growth program initiates with a reduction of cell elongation followed by the progressive loss of meristematic cells. At later stages, cell proliferation ceases and cell differentiation takes place at the former cell elongation and meristematic regions of the primary root. In low P, not only the primary but also almost all mature lateral roots enter the determinate developmental program. Kinetic studies of expression of the cell cycle marker CycB1;1:uidA and the quiescent center (QC) identity marker QC46:GUS showed that in low P conditions, reduction in proliferation in the primary root was preceded by alterations in the QC. These results suggest that in Arabidopsis, P limitation can induce a determinate root developmental program that plays an important role in altering root system architecture and that the QC could act as a sensor of environmental signals.

An Introduction to General Relativity and Cosmology

Abstract: 1. How the theory of relativity came into being (a brief historical sketch) Part I. Elements of Differential Geometry: 2. A short sketch of two-dimensional differential geometries 3. Tensors, tensor densities 4. Covariant derivatives 5. Parallel transport and geodesic lines 6. Curvature of a manifold: flat manifolds 7. Riemannian geometry 8. Symmetries of Rieman spaces, invariance of tensors 9. Methods to calculate the curvature quickly - Cartan forms and algebraic computer programs 10. The spatially homogeneous Bianchi-type spacetimes 11. The Petrov classification by the spinor method Part II. The Gravitation Theory: 12. The Einstein equations and the sources of a gravitational field 13. The Maxwell and Einstein-Maxwell equations and the Kaluza-Klein theory 14. Spherically symmetric gravitational field of isolated objects 15. Relativistic hydrodynamics and thermodynamics 16. Relativistic cosmology I: general geometry 17. Relativistic cosmology II: the Robertson-Walker geometry 18. Relativistic cosmology III: the Lemaitre-Tolman geometry 19. Relativistic cosmology IV: generalisations of L-T and related geometries 20. The Kerr solution 21. Subjects omitted in this book References.