An evaluation of the present status of quality assurance program implementation in digital mammography facilities in a developing country.

Quality assurance program (QAP) implementation in mammography is a key aspect to guarantee the acquisition of -quality images and, thus, an opportune diagnosis of breast cancer. A QAP involves planned and systematic actions, such as quality control (QC) tests that will produce consistently high-quality images, while considering low radiation exposure for stakeholders. Currently, there is poor evidence of the current QAP implementation status in developing countries, particularly in Latin America. In this work, 47 Mexican digital mammography facilities were evaluated in terms of their QAP implementation's current status during the period October 2021 to April 2022. A survey of three key indicators of compliance/non-compliance with QAPs was carried out. Also, 17 QC test parameters were assessed in all mammography units according to an international framework. The Kruskal-Wallis test, McNemar test, and Spearman correlation were used to identify the significant correlation between the QC tests and QAP indicators. Statistical analysis showed a significant positive correlation between the QAP indicators and QC parameters that were evaluated, especially associated with an increase in image quality. Almost 90% of the facilities evaluated failed in some QAP indicators, and only 44.68% of the facilities had an updated and current QAP implemented. Successful QAP implementation directly impacted on the QC mammography test results, particularly in terms of image quality, thus conditioning a successful mammography acquisition chain. The results obtained in this work suggest that better regulations need to be implemented to guarantee QAP surveillance, which could mean an increase in opportune diagnosis and management of breast cancer, with improved radiological safety for patients and occupational exposure personnel.

[Self-reported prevalence of fructan food hypersensitivity in university students from the State of Mexico]. / Prevalencia de hipersensibilidad alimentaria a fructanos en estudiantes universitarios del Estado de México.

OBJECTIVE: To determine the self-reported prevalence of fructans food hypersensitivity in a sample of Mexican university students and to investigate the most frequent symptoms, the related foods involved, risk factors and gastrointestinal function status. METHODS: A cross-sectional, descriptive study was conducted in a convenience sample of 412 university students aged from 18 to 35 years. Data were collected about their personal and family history of gastrointestinal diseases, the presence of symptoms after consumption of certain foods, and the severity of their symptoms. RESULTS: The prevalence of fructans food hypersensitivity was 31.1 %; it was higher in women than in men. The most frequent gastrointestinal symptoms were bloating and flatulence. The most frequent extra-intestinal symptoms were fatigue and stress. The food groups related to the occurrence of symptoms were legumes, vegetables, and fruits. Significant association was found between female sex, personal and family history of gastrointestinal diseases and the presence of fructans food hypersensitivity (p < 0.05). Most individuals with fructans food hypersensitivity had mild gastrointestinal dysfunction (67.2 %). CONCLUSIONS: FFH is a common condition, it was found in one third of university students and occurs mainly in women. More research and diffusion about this pathology is required.

OBJECTIVO: Determinar la prevalencia por autorreporte de hipersensibilidad alimentaria a fructanos en una muestra de estudiantes universitarios e investigar los síntomas más frecuentes, los alimentos relacionados, los factores de riesgo y su función gastrointestinal. MÉTODOS: Se realizó un estudio transversal, descriptivo, en una muestra elegida por conveniencia de 412 estudiantes universitarios, de 18 a 35 años. Se recopilaron datos sobre antecedentes personales y familiares de enfermedades gastrointestinales, síntomas secundarios al consumo de ciertos alimentos y severidad de sus síntomas. RESULTADOS: La prevalencia de hipersensibilidad alimentaria a fructanos fue de 31.1 %, mayor en mujeres que en hombres. Los síntomas gastrointestinales más frecuentes fueron distensión y flatulencias y los extraintestinales, fatiga y estrés. Los grupos de alimentos relacionados con la aparición de síntomas fueron leguminosas, vegetales y frutas. Se encontró asociación significativa entre el sexo femenino, la historia personal y familiar de enfermedades gastrointestinales y la presencia de hipersensibilidad alimentaria a fructanos (p < 0.05). La mayoría de los individuos con hipersensibilidad alimentaria a fructanos tuvieron una disfunción gastrointestinal leve (67.2 %). CONCLUSIONES: La hipersensibilidad alimentaria a fructanos es común; se encontró en un tercio de los estudiantes universitarios, principalmente en mujeres. Se necesita mayor investigación y difusión sobre esta patología.

Photoprotective Activity of Buddleja cordata Cell Culture Methanolic Extract on UVB-irradiated 3T3-Swiss Albino Fibroblasts.

The research on compounds exhibiting photoprotection against ultraviolet radiation (UVR) is a matter of increasing interest. The methanolic extract of a cell culture of Buddleja cordata has potential photoprotective effects as these cells produce phenolic secondary metabolites (SMs). These metabolites are attributed with biological activities capable of counteracting the harmful effects caused by UVR on skin. In the present work, the methanolic extract (310-2500 µg/mL) of B. cordata cell culture showed a photoprotective effect on UVB-irradiated 3T3-Swiss albino fibroblasts with a significant increase in cell viability. The greatest photoprotective effect (75%) of the extract was observed at 2500 µg/mL, which was statistically comparable with that of 250 µg/mL verbascoside, used as positive control. In addition, concentrations of the extract higher than 2500 µg/mL resulted in decreased cell viability (≤83%) after 24 h of exposure. Phytochemical analysis of the extract allowed us to determine that it was characterized by high concentrations of total phenol and total phenolic acid contents (138 ± 4.7 mg gallic acid equivalents and 44.01 ± 1.33 mg verbascoside equivalents per gram of extract, respectively) as well as absorption of UV light (first and second bands peaking at 294 and 330 nm, respectively). Some phenylethanoid glycosides were identified from the extract.

Lyophilized Polyvinylpyrrolidone Hydrogel for Culture of Human Oral Mucosa Stem Cells.

This work shows the synthesis of a polyvinylpyrrolidone (PVP) hydrogel by heat-activated polymerization and explores the production of hydrogels with an open porous network by lyophilisation to allow the three-dimensional culture of human oral mucosa stem cells (hOMSCs). The swollen hydrogel showed a storage modulus similar to oral mucosa and elastic solid rheological behaviour without sol transition. A comprehensive characterization of porosity by scanning electron microscopy, mercury intrusion porosimetry and nano-computed tomography (with spatial resolution below 1 µm) showed that lyophilisation resulted in the heterogeneous incorporation of closed oval-like pores in the hydrogel with broad size distribution (5 to 180 µm, d50 = 65 µm). Human oral mucosa biopsies were used to isolate hOMSCs, expressing typical markers of mesenchymal stem cells in more than 95% of the cell population. Direct contact cytotoxicity assay demonstrated that PVP hydrogel have no negative effect on cell metabolic activity, allowing the culture of hOMSCs with normal fusiform morphology. Pore connectivity should be improved in future to allow cell growth in the bulk of the PVP hydrogel.

Metropolitan age-specific mortality trends at borough and neighborhood level: The case of Mexico City.

Understanding the spatial and temporal patterns of mortality rates in a highly heterogeneous metropolis, is a matter of public policy interest. In this context, there is no, to the best of our knowledge, previous studies that correlate both spatio-temporal and age-specific mortality rates in Mexico City. Spatio-temporal Kriging modeling was used over five age-specific mortality rates (from the years 2000 to 2016 in Mexico City), to gain both spatial (borough and neighborhood) and temporal (year and trimester) data level description. Mortality age-specific patterns have been modeled using multilevel modeling for longitudinal data. Posterior tests were carried out to compare mortality averages between geo-spatial locations. Mortality correlation extends in all study groups for as long as 12 years and as far as 13.27 km. The highest mortality rate takes place in the Cuauhtémoc borough, the commercial, touristic and cultural core downtown of Mexico City. On the contrary, Tlalpan borough is the one with the lowest mortality rates in all the study groups. Post-productive mortality is the first age-specific cause of death, followed by infant, productive, pre-school and scholar groups. The combinations of spatio-temporal Kriging estimation and time-evolution linear mixed-effect models, allowed us to unveil relevant time and location trends that may be useful for public policy planning in Mexico City.

Synthesis and characterization of a polymeric network made of polyethylene glycol and chitosan as a treatment with antibacterial properties for skin wounds.

Polyethylene glycol has been widely investigated for wound healing and dressing applications. Despite its advantages (i.e. great biocompatibility), polyethylene glycol lacks antibacterial activity. For this reason, semi-interpenetrated polymeric networks were prepared by combining a chemically cross-linked polyethylene glycol network with chitosan. The aim of this work was to identify the best amount of chitosan able to improve the antibacterial properties against Staphylococcus aureus. Briefly, the networks were synthesized by a sequential method, adding chitosan in different proportion to the polyethylene glycol. The antibacterial activity was tested following the MGA 0100 of the Pharmacopeia of the United States of Mexico. Fourier-transform infrared with attenuated total reflection spectroscopy, scanning electron microscopy and swelling behavior PBS at 37° C and room temperature were also performed to characterize the polymeric networks. The results showed that PC-2% was able to inhibit the bacterial growth of Staphylococcus aureus even more than Fosfomycin antibiotic. The networks showed cylindrical pores of different sizes (50-100 µm). The maximum swelling of all the networks was achieved in PBS at 37°C (>315%). Free hemoglobin and hemolysis assays were also evaluated to know the compatibility with erythrocytes. Human dermal fibroblasts were used to evaluate direct cytotoxicity. Therefore, the produced gels exerted interesting antibacterial activity and showed good biocompatibility properties.

Spatio-Temporal Representativeness of Air Quality Monitoring Stations in Mexico City: Implications for Public Health.

Assessment of the air quality in metropolitan areas is a major challenge in environmental sciences. Issues related include the distribution of monitoring stations, their spatial range, or missing information. In Mexico City, stations have been located spanning the entire Metropolitan zone for pollutants, such as CO, NO2, O3, SO2, PM2.5, PM10, NO, NO x , and PM CO . A fundamental question is whether the number and location of such stations are adequate to optimally cover the city. By analyzing spatio-temporal correlations for pollutant measurements, we evaluated the distribution and performance of monitoring stations in Mexico City from 2009 to 2018. Based on our analysis, air quality evaluation of those contaminants is adequate to cover the 16 boroughs of Mexico City, with the exception of SO2, since its spatial range is shorter than the one needed to cover the whole surface of the city. We observed that NO and NO x concentrations must be taken into account since their long-range dispersion may have relevant consequences for public health. With this approach, we may be able to propose policy based on systematic criteria to locate new monitoring stations.

Construcción y validación de un cuestionario para medir función gastrointestinal en adultos / Construction and validation of a questionnaire to measure gastrointestinal function in adults

INTRODUCCIÓN: La función gastrointestinal puede alterarse por distintas circunstancias clínicas o por efectos secundarios de algún tratamiento, tal es el caso de los pacientes oncológicos, ya sea por la localización del tumor en el aparato digestivo o por los efectos que produce la quimioterapia, la radioterapia o la cirugía y manifestarse con síntomas que pueden poner en riesgo el estado de nutrición. OBJETIVO: Por la importancia de evaluar la función gastrointestinal el objetivo de este estudio fue crear y validar un cuestionario que permita medirla en población adulta. MATERIAL Y MÉTODOS: La construcción del cuestionario se basó en la realización de distintas versiones que se fueron modificando después de la opinión y observaciones de parte un panel de expertos y de un pilotaje a 100 pacientes con cáncer. La validación se basó en la aplicación del cuestionario a 898 personas con y sin cáncer; para analizar la validez se utilizó Análisis factorial exploratorio y para la confiabilidad Alpha de Cronbach. RESULTADOS: La versión final quedó compuesta por 9 ítems que miden tanto los síntomas gastrointestinales como el ritmo intestinal. Se obtuvo el valor KMO de 0.850 y la prueba de Esfericidad de Bartlett de 2914.41 (gl. de 36). La extracción de los factores mediante el método de Componentes Principales distribuyó a los 9 ítems en 2 dimensiones con pesos factoriales ≥ 0.40, los cuales representan una varianza acumulada del 58.89%. En cuanto a la confiabilidad, se determinó por el análisis de Alpha de Cronbach, para el total del instrumento (9 ítems) y se obtuvo un valor de 0.844. CONCLUSIONES: El diseño de este cuestionario permite conocer la función gastrointestinal en personas adultas ya que identifica el nivel de gravedad de los síntomas gastrointestinales. Los niveles de confiabilidad nos aseguran que el cuestionario valora adecuadamente la función gastrointestinal

INTRODUCTION: Gastrointestinal function can be altered by different clinical circumstances, for example side effects of a treatment. In cancer patients, the gastrointestinal function is modified either due to the location of the tumor in the digestive system or by the side effects of chemotherapy, radiotherapy or surgery. This can be manifested with symptoms that could be a nutritional risk. AIM: To create and validate a questionnaire to measure gastrointestinal function in adults. MATERIAL AND METHODS: The construction of the questionnaire was based on different versions. The questionnaire was modified after the opinion and observations of expert panels and a pilot study of 100 patients with cancer. The validation was performed based on the application of the questionnaire to 898 participants. For the statistical analysis Cronbach's Alpha and Exploratory Factor analysis was performed. RESULTS: The final version of the questionnaire was integrated with 9 items that measure both gastrointestinal symptoms and intestinal rhythm. The KMO value was 0.850 and Bartlett's Sphericity test was 2914.41 (gl. of 36). The extraction of the factors by Principal Components Analysis distributed the 9 items in 2 dimensions with factors ≥ 0.40, which represent an accumulated variance of 58.89%. About trustworthy was determined by Cronbach's Alpha analysis, for the total 9 items the value obtained was 0.844. CONCLUSIONS: The design of this questionnaire allows to measure the gastrointestinal function in adults, also the identification of the level of severity of the gastrointestinal symptoms. The confidence levels assure that the questionnaire assess the gastrointestinal function adequately

Effect of parenteral glutamine in patients with gastrointestinal cancer undergoing surgery / Efecto de la glutamina parenteral en pacientes con cáncer gastrointestinal sometidos a cirugía

Background and objective: malnutrition during cancer treatment is common in patients; therefore, nutritional intervention has an important role in cancer prognosis. Total parenteral nutrition is indicated for patients subjected to a major surgery with gastrointestinal complications. Nutritional support could be improved with glutamine (Gln). Therefore, in this work, the effect of parenteral glutamine in patients with gastrointestinal cancer undergoing surgery was studied. Material and methods: patients were classifi ed into two groups: non-supplemented and supplemented (Gln; 0.4 g/kg/day). Both groups received parenteral nutrition. One and seven days after surgery the nutritional status was evaluated. Hematic cytometry, protein metabolism and biochemical data were analyzed. A questionnaire was also applied to assess gastrointestinal function. Results: after the intervention, the nutritional status in both groups improved. However, the nutritional condition improved signifi cantly better (p = 0.008) in the supplemented group. According to the gastrointestinal function evaluation, the supplemented group changed from severe to mild dysfunction (p = 0.0001). The non-supplemented group progressed from moderate to severe dysfunction, but no changes in blood cell markers were observed. The supplemented group improved its concentration of lymphocytes (p = 0.014). The plasma albumin concentration did not change in groups, but prealbumin improved signifi cantly (p = 0.012) in the group that was supplemented with Gln. Conclusion: intravenous nutritional support supplemented with glutamine can improve gastrointestinal function, improving the absorption of nutrients, which leads to a better state of nutrition. It also has positive effects on plasma concentration of lymphocytes, monocytes and prealbumin

Introducción y objetivo: los pacientes con cáncer desarrollan desnutrición durante el tratamiento antineoplásico, es por ello que el soporte nutricio tiene un rol importante. La nutrición parenteral es el soporte indicado para pacientes que fueron sometidos a cirugía con complicaciones gastrointestinales; este soporte puede ser suplementado con glutamina. Evaluamos el efecto de la glutamina parenteral en pacientes con cáncer gastrointestinal sometidos a cirugía. Material y métodos: se aleatorizaron los pacientes en dos grupos. Ambos grupos recibieron nutrición parenteral, en un grupo no suplementada y en otro grupo suplementada con glutamina (0,4 g/kg/día). Las medidas se tomaron el día uno y el día siete posteriores a la cirugía; en ambas mediciones se evaluó el estado nutricional, se tomó una muestra sanguínea para analizar parámetros bioquímicos y se aplicó un cuestionario de función gastrointestinal. Resultados: después de la intervención, el estado nutricional mejoró en ambos grupos, sin embargo, en el grupo suplementado mejoró significativamente (p = 0,008). De acuerdo a la función gastrointestinal, el grupo suplementado progresó de disfunción severa a leve (p = 0,0001), mientras que el grupo no suplementado progresó de disfunción moderada a severa. En cuanto a los parámetros bioquímicos, no hubo cambios en el grupo no suplementado. En ambos grupos no hubo cambios en las concentraciones plasmáticas de albúmina. En el grupo suplementado mejoraron de manera significativa las concentraciones de linfocitos (p = 0,014) y prealbúmina (p = 0,012). Conclusión: el apoyo nutricio endovenoso suplementado con glutamina puede mejorar la función gastrointestinal, mejorando la absorción de nutrimentos, lo que conlleva a un mejor estado de nutrición. Asimismo, tiene efectos positivos en las concentraciones plasmáticas de linfocitos y monocitos y prealbúmina

[Allergy to cow's milk protein, or lactose intolerance: a cross-sectional study in university students]. / Alergia a la proteína de la leche de vaca o intolerancia a lactosa: un estudio transversal en estudiantes universitarios.

BACKGROUND: Factors like ethnic origin and geographical area affect the frequency of cow's milk protein allergy (CMPA) and lactose intolerance (LI). Epidemiological information about the non-pediatric population is still missing. OBJECTIVE: To determine the prevalence of CMPA and LI in university students. METHODS: A cross-sectional study of 1200 students of 18 to 25-year-old. A structured questionnaire was applied in order to identify the clinical manifestations triggered by the intake of cow's milk (CM), and these were categorized as linked to CMPA or linked to LI. RESULTS: Thirty students met the criteria for CMPA (prevalence of 2.5 %; CI 95 % = 1.7-3.6 %) and 128 for LI (prevalence of 10.7 %, CI 95 % = : 9.0 % - 12.5 %). The frequency of personal history of food allergy and dust mite allergy was higher in students with CMPA than in students with LI. Oral pruritus, skin and respiratory discomforts were predominant in CMPA. Abdominal cramps and flatulence were predominant in LI. CONCLUSIONS: IL is more frequent than CMPA; which frequency was one in every 10 students; and the frequency of CMPA was one in 400.

Antecedentes: El origen étnico y la zona geográfica influyen en la frecuencia de la alergia a la proteína de leche de vaca (APLV) y de intolerancia a la lactosa. Faltan datos epidemiológicos en población no pediátrica.Objetivo: Determinar la prevalencia de APLV e intolerancia a la lactosa en estudiantes universitarios.Métodos: Estudio transversal de 1200 estudiantes de 18 a 25 años. Se aplicó cuestionario estructurado para identificar manifestaciones clínicas desencadenadas por la ingesta de leche de vaca y fueron categorizadas como relacionadas con APLV o intolerancia a la lactosa.Resultados: 30 estudiantes cubrieron criterios para APLV (prevalencia de 2.5 %; IC 95 % = 1.7-3.6) y 128 para intolerancia a la lactosa (prevalencia de 10.7 %, IC 95 % = 9.0-12.5). Los estudiantes con APLV tuvieron mayor frecuencia de historia personal de alergia a alimentos y alergia a ácaros del polvo casero, comparados con los estudiantes con intolerancia a la lactosa. El prurito oral y las molestias cutáneas y respiratorias predominaron en la APLV. El cólico abdominal y las flatulencias predominaron en la intolerancia a la lactosa.Conclusiones: La intolerancia a la lactosa fue más frecuente que la APLV; se observó en uno de cada 10 estudiantes y la APLV en uno de cada 400.

Tailoring Proteins to Re-Evolve Nature: A Short Review.

Proteins are key biomolecules for most biological processes, their function is related to their conformation that is also dictated by their sequence of amino acids. Through evolution, nature has produced an immense variety of enzymatic tools of high efficiency and selectivity, and thanks to the understanding of the molecular basis of life and the technological advances, scientists have learned to introduce mutations and select mutant enzymes, to optimize and control their molecular fitness characteristics mainly for industrial, medical and environmental applications. The relationship between protein structure and enzymatic functionality is essential, and there are various experimental and instrumental techniques for unravelling the molecular changes, activities and specificities. Protein engineering applies computational tools, in hand with experimental tools for mutations, like directed evolution and rational design, along with screening methods to obtain protein variations with the desired properties under a short time frame. With innovations in technology, it is possible to fine tune properties in proteins and reach new frontiers in their applications. The present review will briefly discuss these points and methods, with a glimpse on their strengths and pitfalls, while giving an overview of the versatility of synthetic proteins and their huge potential for biotechnological and biomedical fields.

Self-reported prevalence of clinical features of allergy to nuts and seeds, and seafood in university students.

BACKGROUND: In developing countries, there is a lack of epidemiological information related to food hypersensitivity, including nuts and seafood. OBJECTIVE: The aim was to determine the prevalence of allergic reactions and clinical manifestations associated with the consumption of nuts and seeds or seafood in university students. METHODS: We designed an observational cross-sectional study. A structured questionnaire was applied to Mexican university students to identify allergic reactions associated with the consumption of nuts and seeds, and seafood. RESULTS: A sample of 1,200 students was included; mean age of 19.7 ± 1.7 years. Prevalence of symptoms associated with the consumption of nuts and seeds, and seafood were 2.8% (33 of 1,200) and 3.5% (42 of 1,200) respectively. The main clinical manifestations were abdominal pain (63.6% in nuts and seeds), flushing (50% in seafood), and pharyngeal oppression (19% in seafood). Prevalence of perceived, probable and systemic allergy to nuts and seeds was 2.8% (95% confidence interval [CI], 2.5%-3.0%), 0.8% (95% CI, 0.3%-1.3%) and 0.2% (95% CI, 0%-0.4%) respectively. On the other hand, the prevalence (perceived, probable, and systemic) associated with seafood consumption was 3.5% (95% CI, 2.5%-4.5%), 1.8% (95% CI, 1.0%-2.5%), and 0.5% (95% CI, 0.1%-0.9%). Walnut and shrimp were the most frequently reported foods. CONCLUSION: For every 100 Mexican university students, approximately 3 or 4 perceived to have allergy attributed to the consumption of some nuts and seeds or seafood, while 1 or 2 students would have a probable reaction to this same type of food. Walnut and shrimp would be causing the higher quantity of food allergic reactions.

Self-report prevalence and associated factors to drug hypersensitivity in Mexican young adults.

BACKGROUND: Drug hypersensitivity is defined as any unfavorable reaction that occurs after the administration of any drug. It may or may not be mediated by the involvement of the immune system. Epidemiological data related to drug hypersensitivity reactions in our country are scarce. OBJECTIVE: To determine the prevalence of drug hypersensitivity in a group of young adults, as well as to identify associated factors. METHODS: A structured questionnaire was applied to young people aged 18 to 25 years. The instrument was oriented to identify reactions of drug hypersensitivity, as well as the most prevalent drugs involved. In addition, a personal and family history of atopic diseases was included. Analysis for associations between variables was been done through logistic regression. RESULTS: The prevalence of drug hypersensitivity reactions was 12% (144 of 1,200). The antibiotics were the agents most related to hypersensitivity reactions (9.8%) followed by nonsteroidal anti-inflammatory drugs (1.6%). Factors associated with drug hypersensitivity were a personal history of asthma, odds ratio (OR) 3.15 (95% confidence interval [CI], 1.44-6.91), maternal and paternal history of drug hypersensitivity, OR 2.33 (95% CI, 1.21-4.48) and OR 3.11 (95% CI, 1.22-7.92), respectively. CONCLUSION: The results of this research show that drug hypersensitivity in young adults is a highly prevalent event and it is associated with personal history of asthma and history of drug hypersensitivity in parents.

Preparation of Quantum Dots Hydrogel Nanocomposites with Improved Cytotoxicity.

Nanocomposites are materials with unique properties and a wide range of applications. The combination of different nanostructures with traditional materials gives a variety of possibilities that should be analyzed. Especially, functional fluorescent semiconductor quantum dots (QDs) embedded in polymeric matrices have shown promising fluorescence and biocompatibility properties. These hybrid materials can be used in medical applications such as biodiagnostic and bioimaging. In this study, two hydrogels, one of polyethylene glycol diacrylate (PEGDA) and other of polyacrylamide (PAAm), were prepared with quantum dots of CdTe (4 nm of diameter) and characterized. The aim of this research was to analyze the optical properties of the nanocomposites and their cell viability. QDs nanocomposites were fabricated by a free radical polymerization process. The optical studies showed that the nanocomposites have well defined properties of fluorescence. To study the biocompatibility of the nanocomposites, metastatic B16f10 cell line were used and MTT assay was performed. The nanocomposites had a significant improved cell viability compared with QDs solutions.

Hydrogels based on poly(ethylene glycol) as scaffolds for tissue engineering application: biocompatibility assessment and effect of the sterilization process.

Hydrogels are suitable materials to promote cell proliferation and tissue support because of their hydrophilic nature, porous structure and sticky properties. However, hydrogel synthesis involves the addition of additives that can increase the risk of inducing cytotoxicity. Sterilization is a critical process for hydrogel clinical use as a proper scaffold for tissue engineering. In this study, poly(ethylene glycol) (PEG), poly(ethylene glycol)-chitosan (PEG-CH) and multi-arm PEG hydrogels were synthesized by free radical polymerization and sterilized by gamma irradiation or disinfected using 70 % ethanol. The biocompatibility assessment in human fibroblasts and hemocompatibility studies (hemolysis, platelet aggregation, morphology of mononuclear cells and viability) in peripheral blood from healthy volunteers (ex vivo), were performed. The sterilization or disinfection effect on hydrogel structures was evaluated by FT-IR spectroscopy. Results indicated that hydrogels do not induce any damage to fibroblasts, erythrocytes, platelets or mononuclear cells. Moreover, there was no significant difference in the biocompatibility after the sterilization or disinfection treatment. However, after gamma irradiation, several IR spectroscopic bands were shifted to higher or lower energies with different intensity in all hydrogels. In particular, several bands associated to carboxyl or hydroxyl groups were slightly shifted, possibly associated to scission reactions. The disinfection treatment (70 % ethanol) and γ-irradiation at 13.83 ± 0.7 kGy did not induce morphological damages and yielded sterile and biocompatible PEG hydrogels potentially useful for clinical applications.

In vitro evaluation of the mutagenic and cytostatic effect of Tamaron, Lannate and Manzate alone and in mixture.

Pesticides are often used in agriculture, especially in floriculture. They are frequently applied in binary or ternary mixtures. Nevertheless, their impact on the genetic material has been scarcely explored. In this study, the mutagenic and cytostatic effect of three widely used pesticides, alone and combined, were analyzed. Briefly, lymphocytes cultures were obtained from peripheral blood samples of five healthy donors to determine the sister chromatid exchange and the replicative index (RI). Then, lymphocytes were exposed to Tamaron (100 ppm), Lannate (200 ppm) and Manzate (300 ppm) alone and combined. For the binary mixtures, the concentrations used were 50 ppm of Tamaron, 100 ppm of Lannate and 150 ppm of Manzate. For the ternary mixtures the following concentrations were used: Tamaron (33 ppm), Lannate (70 ppm) and Manzate (100 ppm). Finally, differential staining was performed. It was found that the frequency of SCE/cell showed a significant difference (P ≤ 0.05) between the control (2.66) and the individual treatments of Tamaron (4.87), Lannate: (5.12) and Manzate (4.23). Also, the values of the SCE in the binary mixture of Tamaron+Lannate (5.57), Tamaron+Manzate (6.06) and Lannate+Manzate (6.22) and the ternary mixture (6.63) were statistically different compared to the control. In the RI there was a significant difference between the control (1.98) and the Manzate (1.87). RI differences were also statistically significant (P ≤ 0.05) in mixtures of Tamaron+Lannate (1.64), Tamaron+Manzate (1.63), Lannate+Manzate (1.69) and total mixture (1.53). Therefore, it is suggested that these pesticides alone and in mixtures have both mutagenic and cytostatic synergistic effect in human lymphocytes in vitro.

Self-reported prevalence and risk factors associated with food hypersensitivity in Mexican young adults.

BACKGROUND: Food hypersensitivity (FH) is defined as any unfavorable reaction after the ingestion, contact, or inhalation of a food. Few FH prevalence studies have been performed in the Mexican adult population. OBJECTIVE: To determine the prevalence of self-reported FH and probable food allergy (FA) among a sample of Mexican young adults and to determine the most commonly involved foods, associated symptoms, and risk factors. METHODS: We designed an observational, cross-sectional study in which 1,253 young adults (aged 18-25 years) born in the State of Mexico answered a questionnaire concerning FH. We obtained information on personal and familial histories of allergic diseases, the involved foods, and the subsequent adverse reactions to their consumption. RESULTS: The prevalence of FH was 30.1% and was significantly higher in women than in men (P < .001). The prevalence of probable FA was 5.9% and was also higher in women (P = .02). Gastrointestinal symptoms were reported in 83.1% of FH cases, whereas cutaneous symptoms and oral allergy syndrome were reported in FA cases. The food groups most associated with FH were dairy products (13.2%), vegetables (10.0%), and fruits (8.0%). The food groups most associated with FA were fruits (3.0%) and seafood (1.8%). Female sex, personal history of allergic diseases, maternal history of atopic dermatitis, and parental history of urticaria were significantly associated (P < .05) with the presence of FH. CONCLUSION: FH in young adults might be more common than previously thought, especially in women. However, further studies are needed to confirm this situation in the Mexican population.

Peripheral Pathways in the Food-Intake Control towards the Adipose-Intestinal Missing Link.

In the physiological state a multitude of gut hormones are released into the circulation at the same time depending on the quality and quantity of the diet. These hormones interact with receptors at various points in the "gut-brain axis" to affect short-term and intermediate-term feelings of hunger and satiety. The combined effects of macronutrients on the predominant gut hormone secretion are still poorly understood. Besides, adipokines form an important part of an "adipoinsular axis" dysregulation which may contribute to ß -cell failure and hence to type 2 diabetes mellitus (T2DM). Even more, gestational diabetes mellitus (GDM) and T2DM seem to share a genetic basis. In susceptible individuals, chronic exaggerated stimulation of the proximal gut with fat and carbohydrates may induce overproduction of an unknown factor that causes impairment of incretin production and/or action, leading to insufficient or untimely production of insulin, so that glucose intolerance develops. The bypass of the duodenum and jejunum might avoid a putative hormone overproduction in the proximal foregut in diabetic patients that might counteract the action of insulin, while the early presentation of undigested or incompletely digested food to the ileum may anticipate the production of hormones such as GLP1, further improving insulin action.

Nanoscopic mechanical anisotropy in hydrogel surfaces.

The bulk mechanical properties of soft materials have been studied widely, but it is unclear to what extent macroscopic behavior is reflected in nanomechanics. Using an atomic force microscopy (AFM) imaging method called force spectroscopy mapping (FSM), it is possible to map the nanoscopic spatial distribution of Young's modulus, i.e. "stiffness," and determine if soft or stiff polymer domains exist to correlate nano- and macro-mechanics. Two model hydrogel systems typically used in cell culture and polymerized by a free radical polymerization process, i.e. poly (vinyl pyrrolidone) (PVP) and poly(acrylamide) (PAam) hydrogels, were found to have significantly different nanomechanical behavior despite relatively similar bulk stiffness and roughness. PVP gels contained a large number of soft and stiff nanodomains, and their size was inversely related to crosslinking density and changes in crosslinking efficiency within the hydrogel. In contrast, PAam gels displayed small nanodomains occuring at low frequency, indicating relatively uniform polymerization. Given the responsiveness of cells to changes in gel stiffness, inhomogeneities found in the PVP network indicate that careful nanomechanical characterization of polymer substrates is necessary to appreciate complex cell behavior.