Methodological Proposal for the Adequate Use of the Osteotechnics Technique / Propuesta Metodológica para el uso Adecuado de la Técnica Osteotécnica

SUMMARY: Osteotechnics is one of the different anatomical preservation techniques and can be defined as the technique designed to prepare, clean, obtain and preserve bone structures that can be used in the teaching, museographic or research field. The osteotechnical technique procedure consists of the following phases: debulk and disjoint, maceration, cooking, cleaning, degreasing, bleaching, and labeling to obtain bone material. Seven phases will be explained in detail, as well as the materials, instruments, quantities of the substances used, and the time required to obtain human bone material. We consider that this article can serve as a guide, given that all the experimentation was carried out with human biological material. This methodological proposal could be consolidated and established based on the experience acquired during the creation of the contemporary skeletal collection of the department of innovation in human biological material (DIMBIH). Therefore, the purpose of our proposal is to provide tools that facilitate the work of those who carry out this work and fundamentally to avoid irreversible or irreparable damage to the osteological material, since it is of great value and difficult to acquire for disciplines as anatomy, veterinary, physical and forensic anthropology, medicine, dentistry and biology.

La osteotecnia es una de las técnicas diferentes de conservación anatómica y puede definirse como la técnica destinada a preparar, limpiar, obtener y conservar estructuras óseas que pueden ser utilizadas en el ámbito docente, museográfico o de investigación. El procedimiento de la técnica osteotécnica consta de las siguientes fases: descarnado y desarticulado, maceración, cocción, limpieza, desengrase, blanqueo y marcaje para la obtención de material óseo. Se explicarán en detalle siete fases, así como los materiales, instrumentos, cantidades de las sustancias utilizadas y el tiempo necesario para obtener material óseo humano. Consideramos que este artículo puede servir de guía, dado que toda la experimentación se realizó con material biológico humano. Esta propuesta metodológica pudo consolidarse y establecerse a partir de la experiencia adquirida durante la creación de la colección esquelética contemporánea del Departamento de Innovación en Material Biológico Humano (DIMBIH). Por lo tanto, el propósito de nuestra propuesta es brindar herramientas que faciliten el trabajo de quienes realizan este trabajo y fundamentalmente evitar daños irreversibles o irreparables en el material osteológico, ya que es de gran valor y difícil adquisición para las disciplinas como la anatomía, veterinaria, antropología física y forense, medicina, odontología y biología.

Human papilloma virus presence and its physical status in primary pterygium.

Pterygium is one of the most frequent pathologies in ophthalmology, and is a benign, overgrowth of fibrovascular tissue, often with a wing-like appearance, from the conjunctiva over the cornea. It is composed of an epithelium and highly vascular, sub-epithelial, loose connective tissue. There is much debate surround the pathogenesis of pterygium and a number of theories have been put forward including genetic instability, cellular proliferation, inflammatory influence, and degeneration of connective tissue, angiogenesis, aberrant apoptosis and viral infection. At present, the involvement of human papillomavirus (HPV) in the genesis of pterygium is controversial, as have reported that HPV is present in 58% of cases, while others have failed to detect HPV in pterygium. In this study, we evaluated the presence and viral genotype of HPV DNA in pterygia and healthy conjunctiva sample, and virus integration into the cellular genome. Forty primary pterygia samples and 12 healthy conjunctiva samples were analyzed to HPV DNA presence by polymerase chain reaction, using MY09/MY11 primers of HPV-L1 gene. Viral genotype was identified by DNA sequence analysis of this amplicon. HPV integration into the cellular genome was analyzed by western blot detecting HPV-L1 capsid protein. Presence of HPV was observed in 19 of the 40 pterygia samples. In contrast, healthy conjunctiva samples were negative. To determine virus type, sequence analyses were performed. Interestingly, 11 out of the 19-pterygium samples were identified as HPV-11 type, meanwhile, the remaining 8 pterygium samples were identified as HPV-18. HPV-L1 capsid protein were found only in 3 out of the 10 samples studied. In conclusion, our study identified the presence of HPV DNA exclusively in pterygium samples and described HPV-11 and -18 genotypes. Our results suggest that HPV may be involved in the pathogenesis of pterygium. On the other hand, the expression of the L1-HPV protein suggests viral integration into the cellular genome.

Estudio de los factores de riesgo de deterioro cognitivo en el medio rural: metodología y pilotaje desde la farmacia comunitaria / Assessing risk factors for cognitive impairment in rural areas: methodology and pilot study in community pharmacy

Introducción: el deterioro cognitivo está mediado por la exposición a una gran variedad de factores de riesgo, entre los que la edad es el más relevante. El fenómeno global del envejecimiento de la población hace que conseguir separar los conceptos de envejecimiento y enfermedad sea una tarea de gran interés. En España, la población rural es un estrato particularmente envejecido que puede tener dificultades de acceso a los servicios sanitarios. Las farmacias comunitarias están ampliamente distribuidas en nuestra geografía y el farmacéutico es el sanitario más accesible para esta población tan vulnerable. Métodos: se ha diseñado y pilotado una metodología para evaluar el deterioro cognitivo y el envejecimiento saludable desde la farmacia comunitaria en nuestro medio, utilizando un cuestionario ad hoc compuesto por tests validados para población española, dividido en cinco secciones: deterioro cognitivo, factores sociodemográficos, problemas de salud, estilo de vida y factores psicosociales. Resultados: la prevalencia encontrada para el deterioro cognitivo y el envejecimiento saludable fue de 28,2 % y 15,4 %, respectivamente. La prevalencia (o el valor medio poblacional) calculado para factores de riesgo o factores protectores de deterioro cognitivo resultó compatible con los datos publicados para población española. Los resultados mostraron que este cuestionario puede resultar adecuado para la recogida de información acerca de las variables relacionadas con el deterioro cognitivo en nuestro entorno. Conclusión: el estudio de la influencia de cada factor sobre el deterioro cognitivo debe ser abordado con detalle debido a las complejas interrelaciones existentes entre ellos. En este sentido, las variables más novedosas, como son los factores psicosociales, deben constituir uno de los objetivos prioritarios (AU)

Branched chain amino acids catabolism as a source of new drug targets in pathogenic protists.

Leucine, isoleucine, and valine, collectively termed Branched Chain Amino Acids (BCAA), are hydrophobic amino acids (AAs) and are essential for most eukaryotes since in these organisms they cannot be biosynthesized and must be supplied by the diet. These AAs are structurally relevant for muscle cells and, of course, important for the protein synthesis process. The metabolism of BCAA and its participation in different biological processes in mammals have been relatively well described. However, for other organisms as pathogenic parasites, the literature is really scarce. Here we review the BCAA catabolism, compile evidence on their relevance for pathogenic eukaryotes with special emphasis on kinetoplastids and highlight unique aspects of this underrated pathway.

Servicio de indicación farmacéutica a pacientes tratados con medicamentos de estrecho margen terapéutico / Minor ailment service for patients treated with narrow therapeutic index drug

Se estudian los casos de dos pacientes que demandan nuestro servicio de indicación farmacéutica porque presentan sintomatología digestiva inespecífica. Ambos están siendo tratados con fármacos de estrecho margen terapéutico (carbonato de litio y digoxina, respectivamente). Durante la indicación, el análisis de la medicación revela la posibilidad de que la clínica que ambos manifiestan guarde relación con estos tratamientos en distinta medida: en el caso del carbonato de litio, por tratarse de una reacción adversa frecuente en tratamientos prolongados, y en el de la digoxina, porque la sintomatología va acompañada de bradicardia. En consecuencia, se proponen dos intervenciones, siendo una de ellas la derivación urgente al médico de atención primaria. El análisis de los tratamientos farmacológicos crónicos prescritos a los pacientes, especialmente aquellos de estrecho margen terapéutico, durante el proceso de indicación, es un punto clave para discriminar entre clínica debida exclusivamente a síntomas menores y otras situaciones que pueden incluso comprometer la vida. (AU)

Predictores de muerte en pacientes hospitalizados por neumonía adquirida en la comunidad / Predictors of death in patients hospitalized for community-acquired pneumonia

Fundamento: la neumonía adquirida en la comunidad constituye un importante problema de salud dada su elevada incidencia y relación con la mortalidad. Objetivo: Evaluar la asociación de factores seleccionados con la letalidad en pacientes hospitalizados por neumonía adquirida en la comunidad. Método: estudio descriptivo que incluyó 1.809 pacientes con neumonía hospitalizados entre los años 2012 y 2020. Fueron evaluados factores relacionados con el paciente, con la enfermedad y con la intervención terapéutica, como variables independientes; como variable dependiente fue considerado el estado al alta. En el análisis estadístico, que incluyó análisis bivariado y multivariado (regresión logística), se utilizó el odds ratio y su intervalo de confianza de 95%. Resultados: Se demostró asociación significativa entre varias condiciones evaluadas y la letalidad por neumonía; los factores que mostraron mayor fuerza de asociación fueron la edad de 60 años o más (OR 4,8[2,9;7,9]), el estado de gravedad al ingreso (OR 2,7[2;3,5]), el encamamiento durante la hospitalización (OR 2,5[1,9;3,3]), el encamamiento previo al ingreso (OR 2[1,5;2,7]), el no tratamiento adecuado de las comorbilidades (OR 1,8[1,07;3,3]) y la extensión radiológica del proceso neumónico más allá de un lóbulo (OR 1,7[1,3;2,2]). Conclusiones: Se reafirma el relevante papel que desempeñan una serie de factores relacionados con condicionantes del paciente, con la propia enfermedad y con la intervención médica, en las probabilidades de morir por esta afección. (AU)

Background: community-acquired pneumonia is an important health problem given its high incidence and relationship with mortality. Objective: to evaluate the association of selected factors with lethality in patients hospitalized for community-acquired pneumonia. Method: descriptive study that included 1,809 patients with pneumonia hospitalized between 2012 and 2020. Factors related to the patient, the disease, and the therapeutic intervention were evaluated as independent variables; The state at discharge was considered as the dependent variable. In the statistical analysis, which included bivariate and multivariate analysis (logistic regression), the odds ratio and its 95% confidence interval were used. Results: a significant association was demonstrated between several conditions evaluated and the lethality due to pneumonia; the factors that showed the greatest strength of association were age 60 years or older (OR 4.8[2.9;7.9]), severity status at admission (OR 2.7[2;3.5] ), bedridden during hospitalization (OR 2.5[1.9;3.3]), bedridden prior to admission (OR 2[1.5;2.7]), failure to adequately treat comorbidities ( OR 1.8[1.07;3.3]) and radiological extension of the pneumonic process beyond one lobe (OR 1.7[1.3;2.2]). Conclusions: the relevant role played by a series of factors related to the patient's conditions, to the disease itself and to medical intervention, in the chances of dying from this condition is reaffirmed. (AU)

Automatic feedback control by image processing for mixing solutions in a microfluidic device.

Two approaches of an automatic control were studied through mathematical fitting obtained from color mixing saturation curves in polydimethylsiloxane microfluidic devices: The integrative control with variable integral gain and integrative control with constant integral gain. The aim of this work is to control the color percentage decrement when dye is injected. The results indicate that microfluidic systems are very sensitive to changes in flow and the control variable needs to change slowly; that is, it must be small (at least 100 times less than the theoretically calculated values). The control and stabilization of the microfluidic system were achieved for dye percentages above 60%. The controlling color percentage could provide a tool to regulate other parameters' concentration applied to cell culture and alkalinity control (pH) of solutions in microfluidic devices.

Production of bacterial cellulose tubes for biomedical applications: Analysis of the effect of fermentation time on selected properties.

Biosynthesis of bacterial cellulose (BC) in cylindrical oxygen permeable molds allows the production of hollow tubular structures of increasing interest for biomedical applications (artificial blood vessels, ureters, urethra, trachea, esophagus, etc.). In the current contribution a simple set-up is used to obtain BC tubes of predefined dimensions; and the effects of fermentation time on the water holding capacity, nanofibrils network architecture, specific surface area, chemical purity, thermal stability, mechanical properties, and cell adhesion, proliferation and migration of BC tubes are systematically analysed for the first time. The results reported highlight the role of culture time on key properties of the BC tubes produced, with significant differences arising from the denser and more compact fibril arrangements generated at longer fermentation intervals.

miR-19b-3p and miR-20a-5p are associated with the levels of antiphospholipid antibodies in patients with antiphospholipid syndrome.

Monocytes play a key role in pathophysiology of antiphospholipid syndrome (APS), nevertheless it is unclear if microRNA expression is associated with particular APS features. Identify whether miR-19b-3p and miR-20a-5p expression in monocytes are associated with hallmarks of the APS. Fifty-seven APS patients and 18 healthy controls were studied. Expression of miR-19b-3p and miR-20a-5p was measured in monocytes by RT-qPCR. Both miR-19b-3p (AUC = 0.835, 95% CI 0.733-0.938; P < 0.001) and miR-20a-5p (AUC = 0.857, 0.757-0.957; P < 0.001) discriminated APS patients from healthy individuals. A cut-off point of 1.98 for miR-19-3p and 2.18 for miR-20a-5p showed that APS patients with low microRNA expression had higher levels of IgM and IgG anticardiolipin antibodies than patients with high microRNA expression. In addition, APS patients with low microRNA expression had higher IgG anti-ß2 glycoprotein I antibody levels than their counterparts with high microRNA expression. Finally, miR-19b-3p and miR-20a-5p expression levels were significantly higher in APS patients using oral anticoagulants. Monocyte expression of miR-19b-3p and miR-20a-5p is low in APS, and patients with the lowest microRNA expression presented the highest levels of antiphospholipid antibodies.

High-Fidelity Software-Defined Quantum Logic on a Superconducting Qudit.

We present an efficient approach to achieving arbitrary, high-fidelity control of a multilevel quantum system using optimal control techniques. As an demonstration, we implement a continuous, software-defined microwave pulse to realize a 0↔2 SWAP gate that achieves an average gate fidelity of 99.4%. We describe our procedure for extracting the system Hamiltonian, calibrating the quantum and classical hardware chain, and evaluating the gate fidelity. Our work represents an alternative, fully generalizable route towards achieving universal quantum control by leveraging optimal control techniques.

Nicotine modulates molecules of the innate immune response in epithelial cells and macrophages during infection with M. tuberculosis.

Smoking increases susceptibility to becoming infected with and developing tuberculosis. Among the components of cigarette smoke, nicotine has been identified as the main immunomodulatory molecule; however, its effect on the innate immune system is unknown. In the present study, the effect of nicotine on molecules of the innate immune system was evaluated. Lung epithelial cells and macrophages were infected with Mycobacterium tuberculosis (Mtb) and/or treated with nicotine. The results show that nicotine alone decreases the expression of the Toll-like receptors (TLR)-2, TLR-4 and NOD-2 in all three cell types, as well as the production of the SP-D surfactant protein in type II pneumocytes. Moreover, it was observed that nicotine decreases the production of interleukin (IL)-6 and C-C chemokine ligand (CCL)5 during Mtb infection in epithelial cells (EpCs), whereas in macrophages derived from human monocytes (MDMs) there is a decrease in IL-8, IL-6, tumor necrosis factor (TNF)-α, IL-10, CCL2, C-X-C chemokine ligand (CXCL)9 and CXCL10 only during infection with Mtb. Although modulation of the expression of cytokines and chemokines appears to be partially mediated by the nicotinic acetylcholine receptor α7, blocking this receptor found no effect on the expression of receptors and SP-D. In summary, it was found that nicotine modulates the expression of innate immunity molecules necessary for the defense against tuberculosis.

Levels of anti-Müllerian hormone in premenopausal women with the antiphospholipid syndrome and its association with the risk of clinical complications.

OBJECTIVE: The study aims to investigate the ovarian reserve in premenopausal women with antiphospholipid syndrome (APS) and to evaluate whether it is associated with cumulative organ damage or the risk of clinical complications. METHODS: This single-center study was conducted in 23 premenopausal female patients (10 with primary APS and 13 with secondary APS) and 24 healthy volunteers. Serum anti-Müllerian hormone (AMH) levels were measured by enzyme-linked immunoassay. Disease-specific organ damage (DIAPS score) and the risk of clinical complications (aGAPSS score) were additionally evaluated in APS patients. RESULTS: Serum AMH levels were similar in APS patients (median 6.06, interquartile range 4.31-7.54 ng/ml) and in controls (4.87, 2.64-6.40 ng/ml; P = 0.116), and no differences were observed between the primary (6.60, 5.49-8.88 ng/ml) and secondary (6.06, 3.91-7.30 ng/ml; P = 0.532) forms of the syndrome. In individuals with APS, serum AMH levels correlated inversely with the aGAPSS score (rho-0.421, 95% confidence intervals -0.716 to -0.001; P = 0.045), while no associations were observed with the DIAPS score (rho-0.001, -0.423 to 0.422; P = 0.996). CONCLUSIONS: Ovarian reserve is not reduced in premenopausal women with APS. In addition, serum AMH levels may reflect the risk of APS-related clinical complications but not the burden of disease-specific organ damage.

Effect of ultrasound pre-treatment on the physicochemical composition of Agave durangensis leaves and potential enzyme production.

Approximately 1 million tons of agave plants are processed annually by the Mexican tequila and mezcal industry, generating vast amounts of agroindustrial solid waste. This type of lignocellulosic biomass is considered to be agroindustrial residue, which can be used to produce enzymes, giving it added value. However, the structure of lignocellulosic biomass makes it highly recalcitrant, and results in relatively low yield when used in its native form. The aim of this study was to investigate an effective pre-treatment method for the production of commercially important hydrolytic enzymes. In this work, the physical and chemical modification of Agave durangensis leaves was analysed using ultrasound and high temperature as pre-treatments, and production of enzymes was evaluated. The pre-treatments resulted in modification of the lignocellulosic structure and composition; the ultrasound pre-treatment improved the production of inulinase by 4 U/mg and cellulase by 0.297 U/mg, and thermal pre-treatment improved ß-fructofuranosidase by 30 U/mg.

Increased Training Intensity Induces Proper Membrane Localization of Actin Remodeling Proteins in the Hippocampus Preventing Cognitive Deficits: Implications for Fragile X Syndrome.

Behavioral intervention therapy has proven beneficial in the treatment of autism and intellectual disabilities (ID), raising the possibility of certain changes in molecular mechanisms activated by these interventions that may promote learning. Fragile X syndrome (FXS) is a neurodevelopmental disorder characterized by autistic features and intellectual disability and can serve as a model to examine mechanisms that promote learning. FXS results from mutations in the fragile X mental retardation 1 gene (Fmr1) that prevents expression of the Fmr1 protein (FMRP), a messenger RNA (mRNA) translation regulator at synapses. Among many other functions, FMRP organizes a complex with the actin cytoskeleton-regulating small Rho GTPase Rac1. As in humans, Fmr1 KO mice lacking FMRP display autistic-like behaviors and deformities of actin-rich synaptic structures in addition to impaired hippocampal learning and synaptic plasticity. These features have been previously linked to proper function of actin remodeling proteins that includes Rac1. An important step in Rac1 activation and function is its translocation to the membrane, where it can influence synaptic actin cytoskeleton remodeling during hippocampus-dependent learning. Herein, we report that Fmr1 KO mouse hippocampus exhibits increased levels of membrane-bound Rac1, which may prevent proper learning-induced synaptic changes. We also determine that increasing training intensity during fear conditioning (FC) training restores contextual memory in Fmr1 KO mice and reduces membrane-bound Rac1 in Fmr1 KO hippocampus. Increased training intensity also results in normalized long-term potentiation in hippocampal slices taken from Fmr1 KO mice. These results point to interventional treatments providing new therapeutic options for FXS-related cognitive dysfunction.

Evidence of respiratory syncytial virus and parainfluenza-3 virus in Mexican sheep.

This is a first report in Mexico of the presence of antibodies against respiratory syncytial virus (RSV) and parainfluenza-3 virus in Mexican sheep in different productive stages. We determine the association of serological positivity with age and production system, and obtain molecular evidence of infection by both virus. RSV prevalence in adult sheep was 47% (49/105) at the tropic and 64% (63/99) at the uplands. A significant difference in RSV seropositivity between animals from the tropic and the uplands was observed (P < 0.05). Seropositivity correlated with production system (P = 0.003, OR = 2.042), with a risk of showing antibodies was 2.042 times higher in sheep under an extensive production system. A significant difference in PI3V seropositivity between animals from either provenance (P = 0.017, OR = 0.475) were also found, with a risk of showing antibodies 0.475 times higher in sheep under an extensive production system. Genetic material from RSV and PI3V was identified by RT-PCR in nasal swab samples from clinically healthy lambs and confirmed by sequencing and phylogenetic analysis. Serological results show that sheep are susceptible to infection by both viruses, and molecular results suggest that the identified antibodies are result of natural infections and reinfections.

Intraocular pressure control in patients with primary open angle glaucoma and diabetes mellitus.

OBJECTIVE: To determine the number of hypotensive drugs required to control the intraocular pressure (IOP) in patients with primary open angle glaucoma (POAG) and diabetes mellitus (DM), as well as describing their demographic characteristics. DESIGN: Observational, cross-sectional, and descriptive study. METHODS: Twenty four patients (47 eyes) with definitive diagnosis of DM and POAG were included for a six month follow up, recording demographic data and IOP control. RESULTS: The mean age was 67.04±8.9 years, and 79% of patients were female. Mean time from diagnosis of DM was 13.87 years, and 6.21 years for POAG. No statistical difference was observed between initial and final visual acuity (P = 0.49). There was a statistical difference between initial and final IOP once treatment was started (P = 0.002), requiring 1.9 hypotensive drugs (P < 0.05). Beta-blockers were the most used hypotensive drugs for the initial (41%), as well as the final IOP control medication (28%). CONCLUSION: The mean IOP in patients with DM and POAG was 16.8 mmHg, with the use of 1.9 hypotensive drugs.

Fibromyalgia beyond reductionism. Heart rhythm fractal analysis to assess autonomic nervous system resilience.

OBJECTIVES: The prevailing linear reductionist medical model seems unable to explain complex multisymptomatic illnesses such as fibromyalgia (FM) and similar maladies. Paradigms derived from the complexity theory may provide a coherent framework for these elusive illnesses. Along these lines is the proposal that FM represents a degradation of our main complex adaptive system (the autonomic nervous system, ANS), in a failed effort to adjust to a hostile environment. Healthy complex systems have fractal structures. Heart rate fractal-like variability reflects resilient ANS performance. Our aim was to measure the heart rate variability (HRV) fractal scaling index in FM patients and to correlate this index with clinical symptoms. METHOD: We studied 30 women with FM and 30 controls. All participants filled out questionnaires assessing the severity of FM. The HRV fractal scaling index was estimated during 24 h using detrended fluctuation analysis (DFA). RESULTS: The fractal scaling index alpha-1 was higher in FM patients than in controls (mean ± sd: 1.22 ± 0.10 vs. 1.16 ± 0.09; p = 0.031). There was a positive correlation between the fractal scaling index alpha-1 and the visual analogue scale (VAS) for depression (Spearman's ρ = 0.36, p = 0.04). CONCLUSIONS: The heart rate fractal exponent alpha-1 is altered in FM patients, suggesting a rigid ANS performance. This tangible non-linear finding supports the notion that FM may represent a degradation of our main complex adaptive system, namely the ANS.

miR-509 suppresses brain metastasis of breast cancer cells by modulating RhoC and TNF-α.

The median survival time of breast cancer patients with brain metastasis is less than 6 months, and even a small metastatic lesion often causes severe neurological disabilities. Because of the location of metastatic lesions, a surgical approach is limited and most chemotherapeutic drugs are ineffective owing to the blood brain barrier (BBB). Despite this clinical importance, the molecular basis of the brain metastasis is poorly understood. In this study, we have isolated RNA from samples obtained from primary breast tumors and also from brain metastatic lesions followed by microRNA profiling analysis. Our results revealed that the miR-509 is highly expressed in the primary tumors, whereas the expression of this microRNA is significantly decreased in the brain metastatic lesions. MicroRNA target prediction and the analysis of cytokine array for the cells ectopically expressed with miR-509 demonstrated that this microRNA was capable of modulating the two genes essential for brain invasion, RhoC and TNF-α that affect the invasion of cancer cells and permeability of BBB, respectively. Importantly, high levels of TNF-α and RhoC-induced MMP9 were significantly correlated with brain metastasis-free survival of breast cancer patients. Furthermore, the results of our in vivo experiments indicate that miR-509 significantly suppressed the ability of cancer cells to metastasize to the brain. These findings suggest that miR-509 has a critical role in brain metastasis of breast cancer by modulating the RhoC-TNF-α network and that this miR-509 axis may represent a potential therapeutic target or serve as a prognostic tool for brain metastasis.

A mutant p53/let-7i-axis-regulated gene network drives cell migration, invasion and metastasis.

Most p53 mutations in human cancers are missense mutations resulting in a full-length mutant p53 protein. Besides losing tumor suppressor activity, some hotspot p53 mutants gain oncogenic functions. This effect is mediated in part, through gene expression changes due to inhibition of p63 and p73 by mutant p53 at their target gene promoters. Here, we report that the tumor suppressor microRNA let-7i is downregulated by mutant p53 in multiple cell lines expressing endogenous mutant p53. In breast cancer patients, significantly decreased let-7i levels were associated with missense mutations in p53. Chromatin immunoprecipitation and promoter luciferase assays established let-7i as a transcriptional target of mutant p53 through p63. Introduction of let-7i to mutant p53 cells significantly inhibited migration, invasion and metastasis by repressing a network of oncogenes including E2F5, LIN28B, MYC and NRAS. Our findings demonstrate that repression of let-7i expression by mutant p53 has a key role in enhancing migration, invasion and metastasis.