A global analysis of the reconstitution of PTEN function by translational readthrough of PTEN pathogenic premature termination codons.

The PTEN tumor suppressor gene is mutated with high incidence in tumors and in the germline of patients with cancer predisposition or with macrocephaly associated with autism. PTEN nonsense mutations generating premature termination codons (PTC) and producing nonfunctional truncated PTEN proteins are frequent in association with human disease. However, there are no studies addressing the restoration of full-length PTEN proteins from the PTC-mutated PTEN gene by translational readthrough. Here, we have performed a global translational and functional readthrough analysis of the complete collection of PTEN PTC somatic or hereditary mutations found in tumors or in the germline of patients (disease-associated PTEN PTCome), and we set standards for the analysis of the potential of readthrough functional reconstitution in disease-relevant genes. Our analysis indicates that prevalent pathogenic PTEN PTC mutations are susceptible to PTEN functional restoration in response to readthrough-inducing compounds. Comprehensive readthrough analyses of disease-associated PTComes will be valuable tools for the implementation of readthrough-based precision interventions in specific groups of patients.

Modeling human disease in yeast: recreating the PI3K-PTEN-Akt signaling pathway in Saccharomyces cerevisiae.

The yeast Saccharomyces cerevisiae is a model organism that has been thoroughly exploited to understand the universal mechanisms that govern signaling pathways. Due to its ease of manipulation, humanized yeast models that successfully reproduce the function of human genes permit the development of highly efficient genetic approaches for molecular studies. Of special interest are those pathways related to human disease that are conserved from yeast to mammals. However, it is also possible to engineer yeast cells to implement functions that are naturally absent in fungi. Along the years, we have reconstructed several aspects of the mammalian phosphatidylinositol 3-kinase (PI3K) pathway in S. cerevisiae. Here, we briefly review the use of S. cerevisiae as a tool to study human oncogenes and tumor suppressors, and we present an overview of the models applied to the study of the PI3K oncoproteins, the tumor suppressor PTEN, and the Akt protein kinase. We discuss the application of these models to study the basic functional properties of these signaling proteins, the functional assessment of their clinically relevant variants, and the design of feasible platforms for drug discovery.

Induction of Translational Readthrough on Protein Tyrosine Phosphatases Targeted by Premature Termination Codon Mutations in Human Disease.

Nonsense mutations generating premature termination codons (PTCs) in various genes are frequently associated with somatic cancer and hereditary human diseases since PTCs commonly generate truncated proteins with defective or altered function. Induced translational readthrough during protein biosynthesis facilitates the incorporation of an amino acid at the position of a PTC, allowing the synthesis of a complete protein. This may evade the pathological effect of the PTC mutation and provide new therapeutic opportunities. Several protein tyrosine phosphatases (PTPs) genes are targeted by PTC in human disease, the tumor suppressor PTEN being the more prominent paradigm. Here, using PTEN and laforin as examples, two PTPs from the dual-specificity phosphatase subfamily, we describe methodologies to analyze in silico the distribution and frequency of pathogenic PTC in PTP genes. We also summarize laboratory protocols and technical notes to study the induced translational readthrough reconstitution of the synthesis of PTP targeted by PTC in association with disease in cellular models.

Experience of percutaneous closure of small to large patent ductus arteriosus with Nit-Occlud® device in a tertiary referral hospital in Colombia.

Background: The decision to close patent ductus arteriosus should always be individualized and taken together with the child's family once the risks and benefits of both choices have been exposed. Objective: This study aims to report the experience and outcomes in patients undergoing endovascular closure of small to medium-size PDA with a Nit-Occlud® device in a tertiary referral hospital in Colombia. Methods: Longitudinal descriptive study, which included all patients under 18 years of age who underwent percutaneous ductal closure with Nit-Occlud® device between January 1, 2011, and February 1, 2023. Patients with associated complex congenital heart disease requiring surgical management, pregnant patients, and patients with incomplete data regarding studied variables were excluded from the study. Results: Eighty-seven patients were documented, with a mean age, weight, and height at closure of 51 months, 14 kg, and 95.83 cm, respectively. About 70% of the patients (n = 61) were female, 76% were under 6-years-old and only one patient was over 15. The average size of the ductus at the pulmonary end was 2 mm. Four of the total number of patients did not achieve PDA closure during the procedure. Of the remaining 83, complete immediate closure was achieved in 81 patients. A device exchange for a larger device was required during the same procedure in one of the cases. Two patients presented residual shunt of 0.5 mm during follow-up, and one required a new procedure for device closure 10 months later. Only one device presented repeatedly embolization to the aorta, requiring surgical removal. As a technical difficulty, one device presented repeated passage into the aorta, so it was decided to remove it before releasing it to avoid complications, and given the complex anatomy of the ductus, surgical closure was indicated. Among the complications, one patient presented a hematoma of the subcutaneous tissue in the right thigh, which improved with medical management, and no deaths related to the procedure were registered. Conclusions: Using the Nit-Occlud® device to close small to moderate-sized ductus remains a safe and effective strategy with successful closure rates at 1-year follow-up irrespective of age, weight, height, or whether it involves a small or medium-sized duct. Despite our limitations, results concerning adverse effects are comparable to those observed in multicentric studies conducted in other regions.

Antecdentes: La decisión de cerrar el conducto arterioso permeable (CAP) siempre debe ser individualizada y tomada en conjunto con la familia del niño una vez expuestos los riesgos y beneficios de ambas opciones. Objetivo: Este estudio tiene como objetivo informar la experiencia y los resultados en pacientes sometidos a cierre endovascular del CAP de tamaño pequeño a mediano con un dispositivo Nit-Occlud® en un hospital de tercer nivel de referencia en Colombia. Método: Estudio descriptivo longitudinal, que incluyó a todos los pacientes menores de 18 años a quienes se les realizó cierre ductal percutáneo con dispositivo Nit-Occlud® entre el 1 de enero de 2011 y el 1 de febrero de 2023. Se excluyeron: pacientes con cardiopatía congénita compleja asociada que requirieron manejo quirúrgico, pacientes embarazadas y pacientes con datos incompletos sobre las variables estudiadas. Resultados: Se documentaron 87 pacientes, con edad, peso y talla promedio al cierre de 51 meses, 14 kg y 95.83 cm, respectivamente. El 70% de los pacientes (n = 61) eran mujeres, el 76% tenían menos de seis años y solo un paciente tenía más de 15 años. El tamaño medio del conducto en el extremo pulmonar fue de 2 mm. Cuatro del total de pacientes no lograron el cierre del CAP durante el procedimiento. De los 83 restantes, se logró el cierre inmediato completo en 81 pacientes. En uno de los casos fue necesario cambiar el dispositivo por uno más grande durante el mismo procedimiento. Dos pacientes presentaron shunt residual de 0.5 mm durante el seguimiento y uno requirió un nuevo procedimiento para cierre del dispositivo diez meses después. Solo un dispositivo presentó embolización repetida en la aorta, requiriendo extracción quirúrgica. Como dificultad técnica, un dispositivo presentó paso repetido hacia la aorta, por lo que se decidió retirarlo antes de liberarlo para evitar complicaciones y dada la compleja anatomía del ductus se indicó cierre quirúrgico. Entre las complicaciones, un paciente presentó un hematoma del tejido subcutáneo en el muslo derecho, que mejoró con el manejo médico, y no se registraron muertes relacionadas con el procedimiento. Conclusiones: El uso del dispositivo Nit-Occlud® para cerrar conductos de tamaño pequeño a moderado sigue siendo una estrategia segura y eficaz con tasas de cierre exitoso al año de seguimiento, independientemente de la edad, el peso, la altura o si se trata de un conducto de tamaño pequeño o mediano. A pesar de nuestras limitaciones, los resultados sobre los efectos adversos son comparables a los observados en estudios multicéntricos realizados en otras regiones.

Functional analysis of PTEN variants of unknown significance from PHTS patients unveils complex patterns of PTEN biological activity in disease.

Heterozygous germline mutations in PTEN gene predispose to hamartomas and tumors in different tissues, as well as to neurodevelopmental disorders, and define at genetic level the PTEN Hamartoma Tumor Syndrome (PHTS). The major physiologic role of PTEN protein is the dephosphorylation of phosphatidylinositol (3,4,5)-trisphosphate (PIP3), counteracting the pro-oncogenic function of phosphatidylinositol 3-kinase (PI3K), and PTEN mutations in PHTS patients frequently abrogate PTEN PIP3 catalytic activity. PTEN also displays non-canonical PIP3-independent functions, but their involvement in PHTS pathogeny is less understood. We have previously identified and described, at clinical and genetic level, novel PTEN variants of unknown functional significance in PHTS patients. Here, we have performed an extensive functional characterization of these PTEN variants (c.77 C > T, p.(Thr26Ile), T26I; c.284 C > G, p.(Pro95Arg), P95R; c.529 T > A, p.(Tyr177Asn), Y177N; c.781 C > G, p.(Gln261Glu), Q261E; c.829 A > G, p.(Thr277Ala), T277A; and c.929 A > G, p.(Asp310Gly), D310G), including cell expression levels and protein stability, PIP3-phosphatase activity, and subcellular localization. In addition, caspase-3 cleavage analysis in cells has been assessed using a C2-domain caspase-3 cleavage-specific anti-PTEN antibody. We have found complex patterns of functional activity on PTEN variants, ranging from loss of PIP3-phosphatase activity, diminished protein expression and stability, and altered nuclear/cytoplasmic localization, to intact functional properties, when compared with PTEN wild type. Furthermore, we have found that PTEN cleavage at the C2-domain by the pro-apoptotic protease caspase-3 is diminished in specific PTEN PHTS variants. Our findings illustrate the multifaceted molecular features of pathogenic PTEN protein variants, which could account for the complexity in the genotype/phenotype manifestations of PHTS patients.

Precise Immunodetection of PTEN Protein in Human Neoplasia.

PTEN is a major tumor-suppressor protein whose expression and biological activity are frequently diminished in sporadic or inherited cancers. PTEN gene deletion or loss-of-function mutations favor tumor cell growth and are commonly found in clinical practice. In addition, diminished PTEN protein expression is also frequently observed in tumor samples from cancer patients in the absence of PTEN gene alterations. This makes PTEN protein levels a potential biomarker parameter in clinical oncology, which can guide therapeutic decisions. The specific detection of PTEN protein can be achieved by using highly defined anti-PTEN monoclonal antibodies (mAbs), characterized with precision in terms of sensitivity for the detection technique, specificity for PTEN binding, and constraints of epitope recognition. This is especially relevant taking into consideration that PTEN is highly targeted by mutations and posttranslational modifications, and different PTEN protein isoforms exist. The precise characterization of anti-PTEN mAb reactivity is an important step in the validation of these reagents as diagnostic and prognostic tools in clinical oncology, including their routine use in analytical immunohistochemistry (IHC). Here, we review the current status on the use of well-defined anti-PTEN mAbs for PTEN immunodetection in the clinical context and discuss their potential usefulness and limitations for a more precise cancer diagnosis and patient benefit.

Expression of Human PTEN-L in a Yeast Heterologous Model Unveils Specific N-Terminal Motifs Controlling PTEN-L Subcellular Localization and Function.

The tumour suppressor PTEN is frequently downregulated, mutated or lost in several types of tumours and congenital disorders including PHTS (PTEN Hamartoma Tumour Syndrome) and ASD (Autism Spectrum Disorder). PTEN is a lipid phosphatase whose activity over the lipid messenger PIP3 counteracts the stimulation of the oncogenic phosphatidylinositol 3-kinase (PI3K) pathway. Recently, several extended versions of PTEN produced in the cell by alternative translation initiation have been described, among which, PTEN-L and PTEN-M represent the longest isoforms. We previously developed a humanized yeast model in which the expression of PI3K in Saccharomyces cerevisiae led to growth inhibition that could be suppressed by co-expression of PTEN. Here, we show that the expression of PTEN-L and PTEN-M in yeast results in robust counteracting of PI3K-dependent growth inhibition. N-terminally tagged GFP-PTEN-L was sharply localized at the yeast plasma membrane. Point mutations of a putative membrane-binding helix located at the PTEN-L extension or its deletion shifted localization to nuclear. Also, a shift from plasma membrane to nucleus was observed in mutants at basic amino acid clusters at the PIP2-binding motif, and at the Cα2 and CBR3 loops at the C2 domain. In contrast, C-terminally tagged PTEN-L-GFP displayed mitochondrial localization in yeast, which was shifted to plasma membrane by removing the first 22 PTEN-L residues. Our results suggest an important role of the N-terminal extension of alternative PTEN isoforms on their spatial and functional regulation.

Precise definition of PTEN C-terminal epitopes and its implications in clinical oncology.

Anti-PTEN monoclonal antibodies (mAb) are arising as important tools for immunohistochemistry (IHC) and protein quantification routine analysis in clinical oncology. Although an effort has been made to document the reliability of tumor tissue section immunostaining by anti-PTEN mAb, and to standardize their IHC use in research and in the clinical practice, the precise topological and biochemical definition of the epitope recognized by each mAb has been conventionally overlooked. In this study, six commercial anti-PTEN mAb have been validated and characterized for sensitivity and specificity by IHC and FISH, using a set of prostate and urothelial bladder tumor specimens, and by immunoblot, using PTEN positive and PTEN negative human cell lines. Immunoblot precise epitope mapping, performed using recombinant PTEN variants and mutations, revealed that all mAb recognized linear epitopes of 6-11 amino acid length at the PTEN C-terminus. Tumor-associated or disease-associated mutations at the PTEN C-terminus did not affect subcellular localization or PIP3 phosphatase activity of PTEN in cells, although resulted in specific loss of reactivity for some mAb. Furthermore, specific mimicking-phosphorylation mutations at the PTEN C-terminal region also abolished binding of specific mAb. Our study adds new evidence on the relevance of a precise epitope mapping in the validation of anti-PTEN mAb for their use in the clinics. This will be substantial to provide a more accurate diagnosis in clinical oncology based on PTEN protein expression in tumors and biological fluids.

A pathogenic role for germline PTEN variants which accumulate into the nucleus.

The PTEN gene encodes a master regulator protein that exerts essential functions both in the cytoplasm and in the nucleus. PTEN is mutated in the germline of both patients with heterogeneous tumor syndromic diseases, categorized as PTEN hamartoma tumor syndrome (PHTS), and a group affected with autism spectrum disorders (ASD). Previous studies have unveiled the functional heterogeneity of PTEN variants found in both patient cohorts, making functional studies necessary to provide mechanistic insights related to their pathogenicity. Here, we have functionally characterized a PTEN missense variant [c.49C>G; p.(Gln17Glu); Q17E] associated to both PHTS and ASD patients. The PTEN Q17E variant displayed partially reduced PIP3-catalytic activity and normal stability in cells, as shown using S. cerevisiae and mammalian cell experimental models. Remarkably, PTEN Q17E accumulated in the nucleus, in a process involving the PTEN N-terminal nuclear localization sequence. The analysis of additional germline-associated PTEN N-terminal variants illustrated the existence of a PTEN N-terminal region whose targeting in disease causes PTEN nuclear accumulation, in parallel with defects in PIP3-catalytic activity in cells. Our findings highlight the frequent occurrence of PTEN gene mutations targeting PTEN N-terminus whose pathogenicity may be related, at least in part, with the retention of PTEN in the nucleus. This could be important for the implementation of precision therapies for patients with alterations in the PTEN pathway.

Insights into the pathological mechanisms of p85α mutations using a yeast-based phosphatidylinositol 3-kinase model.

In higher eukaryotes, cell proliferation is regulated by class I phosphatidylinositol 3-kinase (PI3K), which transduces stimuli received from neighboring receptors by local generation of PtdIns(3,4,5)P3 in cellular membranes. PI3K is a heterodimeric protein consisting of a regulatory and a catalytic subunit (p85 and p110 respectively). Heterologous expression of p110α in Saccharomyces cerevisiae leads to toxicity by conversion of essential PtdIns(4,5)P2 into futile PtdIns(3,4,5)P3, providing a humanized yeast model for functional studies on this pathway. Here, we report expression and functional characterization in yeast of all regulatory and catalytic human PI3K isoforms, and exploitation of the most suitable setting to functionally assay panels of tumor- and germ line-associated PI3K mutations, with indications to the limits of the system. The activity of p110α in yeast was not compromised by truncation of its N-terminal adaptor-binding domain (ABD) or inactivation of the Ras-binding domain (RBD). In contrast, a cluster of positively charged residues at the C2 domain was essential. Expression of a membrane-driven p65α oncogenic-truncated version of p85α, but not the full-length protein, led to enhanced activity of α, ß, and δ p110 isoforms. Mutations impairing the inhibitory regulation exerted by the p85α iSH2 domain on the C2 domain of p110α yielded the latter non-responsive to negative regulation, thus reproducing this oncogenic mechanism in yeast. However, p85α germ line mutations associated with short stature, hyperextensibility of joints and/or inguinal hernia, ocular depression, Rieger anomaly, and teething delay (SHORT) syndrome did not increase PI3K activity in this model, supporting the idea that SHORT syndrome-associated p85α mutations operate through mechanisms different from the canonical disruption of inhibitory p85-p110 interactions typical of cancer.

Tailor-Made Protein Tyrosine Phosphatases: In Vitro Site-Directed Mutagenesis of PTEN and PTPRZ-B.

In vitro site-directed mutagenesis (SDM) of protein tyrosine phosphatases (PTPs) is a commonly used approach to experimentally analyze PTP functions at the molecular and cellular level and to establish functional correlations with PTP alterations found in human disease. Here, using the tumor-suppressor PTEN and the receptor-type PTPRZ-B (short isoform from PTPRZ1 gene) phosphatases as examples, we provide a brief insight into the utility of specific mutations in the experimental analysis of PTP functions. We describe a standardized, rapid, and simple method of mutagenesis to perform single and multiple amino acid substitutions, as well as deletions of short nucleotide sequences, based on one-step inverse PCR and DpnI restriction enzyme treatment. This method of SDM is generally applicable to any other protein of interest.

One-Tube-Only Standardized Site-Directed Mutagenesis: An Alternative Approach to Generate Amino Acid Substitution Collections.

Site-directed mutagenesis (SDM) is a powerful tool to create defined collections of protein variants for experimental and clinical purposes, but effectiveness is compromised when a large number of mutations is required. We present here a one-tube-only standardized SDM approach that generates comprehensive collections of amino acid substitution variants, including scanning- and single site-multiple mutations. The approach combines unified mutagenic primer design with the mixing of multiple distinct primer pairs and/or plasmid templates to increase the yield of a single inverse-PCR mutagenesis reaction. Also, a user-friendly program for automatic design of standardized primers for Ala-scanning mutagenesis is made available. Experimental results were compared with a modeling approach together with stochastic simulation data. For single site-multiple mutagenesis purposes and for simultaneous mutagenesis in different plasmid backgrounds, combination of primer sets and/or plasmid templates in a single reaction tube yielded the distinct mutations in a stochastic fashion. For scanning mutagenesis, we found that a combination of overlapping primer sets in a single PCR reaction allowed the yield of different individual mutations, although this yield did not necessarily follow a stochastic trend. Double mutants were generated when the overlap of primer pairs was below 60%. Our results illustrate that one-tube-only SDM effectively reduces the number of reactions required in large-scale mutagenesis strategies, facilitating the generation of comprehensive collections of protein variants suitable for functional analysis.

Factores de riesgo asociados al síndrome metabólico en conductores del transporte público en Cochabamba Bolivia / Risk factors associated with Metabolic Syndrome in car drivers of the public transport from Cochabamba Bolivia

Introducción: el Síndrome Metabólico es un desorden complejo que incrementa el riego de desarrollar Diabetes Mellitus tipo 2 y Enfermedades cardiovasculares. Objetivo: analizar la prevalencia de factores de riesgo asociados al síndrome metabólico en conductores del transporte público en Cochabamba-Bolivia. Métodos: estudio observacional, analítico de corte transversal, en una población de referencia de N=246 conductores de 6 líneas de transporte de la zona sud de Cochabamba-Bolivia; alcanzando una muestra de n=69 sujetos de estudio y aplicando la metodología STEPS de la OPS/OMS. Se utilizó Chi cuadrado (X²) para la asociación estadística con el sexo; regresión logística bi-variada y multivariada para la obtención del OR crudo y ajustado en relación a los factores de riesgo asociados al SM. Resultados: las prevalencias de los factores de riesgo asociados a Síndrome Metabólico fueron: STEP-1: Tabaquismo 20,3%; consumo actual de alcohol 63,8%; bajo consumo de frutas y vegetales 94,2%; sedentarismo o bajo nivel de actividad física 66,7%. STEP-2: sobrepeso 47,8%; obesidad 37,7%; cintura de riesgo u obesidad abdominal 37,7% y presión arterial elevada en 36,4%. STEP3: Glicemia alterada en ayunas 43,9%; Resistencia a la Insulina 47,8%; colesterol total elevado 56,1%; Triglicéridos elevados 66,7% y HDL-colesterol reducido en el 60,6%. Conclusión: el síndrome metabólico es altamente prevalente en la población de conductores del transporte público de la zona sud de la ciudad de Cochabamba (79,3%); asociado al tiempo de trabajo en el rubro, el incremento de edad, la ausencia de pareja y la situación de trabajo.

Background: metabolic Syndrome is a complex disorder that increases the risk of developing Diabetes Mellitus type 2 and cardiovascular diseases. Objective: to analyze the prevalence of risk factors associated with the metabolic syndrome in drivers of public transport in Cochabamba, Bolivia. Methods: a cross-sectional study was conducted, in a reference population of N= 246 car drivers of 6 transport lines in the south zone forme Cochabamba-Bolivia; reaching a sample of n = 69 study subjects and applying the PAHO / WHO STEPS methodology. Chi-square (X²) was used for the statistical association with sex; bi-varied and multivariate logistic regression to obtain the crude and adjusted OR, in relation to the risk factors associated with the MetS. Results: the prevalences of risk factors associated with Metabolic Syndrome were: STEP-1: Smoking 20,3%; current alcohol consumption 63,8%; low consumption of fruits and vegetables 94,2%; sedentary lifestyle or low level of physical activity 66,7%. STEP-2: overweight 47.8%; obesity 37.7%; waist risk or abdominal obesity 37,7% and high blood pressure in 36,4%. STEP3: Hyperglycemia in fasting 43,9%; Insulin resistance 47,8%; high total cholesterol 56.1%; Triglycerides elevated 66,7% and HDL-cholesterol reduced 60,6%. Conclusion: the metabolic syndrome is highly prevalent in the population of drivers of public transport in the south zone from Cochabamba city (79,3%); associated with working time in driving, increase with age, in singles and the employers.

Motivos para el consumo de alcohol y tabaco en estudiantes de la licenciatura de enfermería / Reasons for the consumption of alcohol and tobacco in undergraduate nursing students

Resumen

Introducción: el consumo de alcohol y tabaco es un problema de salud pública. Los motivos para su consumo, en los estudiantes, frecuentemente están relacionados con ambientes estresantes y pueden de origen social, psicológico y físico.

Objetivo: describir la frecuencia de los motivos sociales, psicológicos y físicos que influyen en los estudiantes para el consumo de alcohol y tabaco.

Metodología: estudio descriptivo transversal en 216 estudiantes de licenciatura en enfermería. Se aplicaron dos escalas de motivos, una para el consumo de tabaco y otra para el consumo de alcohol.

Resultados: el 91.2% de los estudiantes consumen alcohol, el 22.4% son hombres y 77.6% son mujeres; más de la mitad (53.7%) de los estudiantes consumen tabaco, siendo, en su mayoría, mujeres (70.6%). Para el consumo de alcohol, el motivo que se presentó con mayor frecuencia fue el social, y para el consumo de tabaco fue el motivo psicológico.

Conclusiones: el consumo de alcohol y tabaco por los estudiantes, es mayor en mujeres que en hombres. Es relevante que el motivo con mayor frecuencia sea el de carácter social y psicológico.

Abstract

Introduction: The consumption of alcohol and tobacco is a public health problem. The reasons for its consumption in students are related to stressful environments and of social, psychological and physical origin.

Objective: To describe the frequency of social, psychological and physical reasons that influence students for alcohol and tobacco use.

Methods: Cross-sectional descriptive study in 216 undergraduate nursing students. Two scales of reasons were applied, one for the consumption of tobacco and another one for the consumption of alcohol.

Results: 91.2% of the students consume alcohol, 22.4% are men and 77.6% are women; more than half (53.7%) of students consumed tobacco, most of them women (70.6%). For the consumption of alcohol the reason that was presented with more frequency was the social and for the consumption of tobacco was the psychological reason.

Conclusions: The consumption of alcohol and tobacco by students is higher in women than in men. It is relevant that the most frequent reason is the social and psychological.

Masa grasa corporal en escolares y adolescentes en la zona de la Tamborada Cochabamba, Bolivia / Mass body fat in schoolchildren and adolescents in the area of the Tamborada Cochabamba, Bolivia

Objetivo: determinar la proporción de masa grasa corporal cuantificada con pliegues subcutáneos en escolares y adolescentes de la zona de Tamborada de Cochabamba. Metodos: estudio descriptivo y transversal. Se evaluaron a 158 escolares y adolescentes de ambos sexos entre 7 a 17 años de edad, que asisten a guarderías y centros de apoyo escolar dependientes del Centro de Desarrollo Integral (CDI). Se evaluó el IMC según edad y sexo. Para el estudio de la distribución grasa corporal, se midieron los cuatro pliegues cutáneos, pliegue tricipital, bicipital, subescapular y suprailíaco, a partir de las ecuaciones de regresión múltiple de Brook y Siri, se obtuvo la densidad y con ello el volumen total de grasa corporal de cada sujeto. Resultados: para el indicador antropométrico IMC no se encontraron diferencias estadísticamente significativas para la variable sexo (p = 0,165). la masa grasa corporal en porcentaje (%); en el género masculino se puede observar que ésta aumenta progresivamente hasta los 12 años y posteriormente disminuye también progresivamente. En el caso de las mujeres desde el inicio se evidencia un ascenso hasta los 13 años, para luego descender en el porcentaje de masa grasa corporal. la asociación entre los valores del porcentaje de grasa corporal y las cifras del índice de masa corporal, hay una correlación muy alta entre ambas variables (r = 0,861; p < 0,001). Discusión y Conclusión: estos datos indican que el índice de masa corporal se incrementa entre los sujetos y las cifras de porcentaje de grasa mostraron un incremento en modo paralelo.

Objective: to determine the proportion of body fat mass quantified with subcutaneous folds in school children and adolescents in the area of "La Tamborada", Cochabamba. Methods: it is a descriptive and transversal study. A total of 158 schoolchildren and adolescents from both sexes and between 7 and 17 years of age that attend day care centers and school support centers under the Integral Development Center (CDI) were evaluated. BMI was assessed by age and sex. For the study of the body fat distribution, the four skinfolds, triceps, bicipital, subscapular and suprailiac fold were measured from Brook's and Siri multiple regression equations, the density was obtained and thus the total volume of Body fat of each subject. Results: for the anthropometric indicator BMI no statistically significant differences were found for the gender variable (p = 0.165). Body fat mass in percentage (%); in the masculine gender it is possible to be observed that this increases progressively until the 12 years and later also diminishes progressively. In the case of women from the beginning, an ascent up to the age of 13 is evident, in order to decrease the percentage of body fat. The association between body fat percentage values and body mass index values, there is a very high correlation between both variables (r = 0.861, p <0.001). Discussion and Conclusion: these data indicate that body mass index is increased between subjects and fat percentage figures showed an increase in parallel mode.

Cell adhesion and proliferation onto chitosan-based membranes treated by plasma surface modification.

Surface properties play a vital role in the functioning of a biomaterial. Cellular adherence and growth onto biomaterials can be enhanced in biomaterial modifications of their surface. In this work, the cell behavior on chitosan membranes modified by argon and nitrogen-plasma treatments was investigated. Characterization of the membranes was performed using atomic force microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. Cytotoxicity assessment and direct contact assay were carried out for untreated and treated chitosan membranes using L929 fibroblast-like cells. Cell morphology and cell viability were assessed to evaluate the cell attachment and proliferation. Changes in terms of roughness, surface chemistry, and hydrophilicity/hydrophobic balance of chitosan-modified membranes were observed. Regarding cell studies, the findings revealed that the extracts of all membranes do not induce cytotoxic effects. Moreover, the in vitro assays evidenced an improvement of the L929 adhesion and attachment when compared to untreated chitosan membranes. Overall, the data obtained clearly demonstrated that plasma treatments constitute an effective way of improving the biocompatibility of chitosan membranes towards to their use in biomedical applications.

Evaluación de los parámetros seminales en pacientes con sospecha de infertilidad en Cochabamba, Bolivia / Assessment of the sperm parameters in patients with suspected of infertility in Cochabamba, Bolivia

Objetivo: evaluar los parámetros seminales en varones con sospecha de infertilidad. Métodos: se analizaron 138 muestras seminales. La evaluación se realizó mediante análisis seminal según criterios de la OMS 2010. Resultados: la edad de los pacientes estaba comprendida entre los 20 a 57 años, con un promedio de 32,8 ± 6,7. El 61,6 % de los pacientes tenían normozoospermia, 9,4 % tenían azoospermia y 0,7% aspermia, el 28,3% presentaron uno o más parámetros alterados (4,3% presentaron alteración en volumen, 5,1% alteración en concentración espermática, 6,5% alteración en movilidad, 0,7% alteración en morfología y 0,7% alteración en vitalidad, el 11% presento más de una alteración). Se observó diferencia significativa entre muestras normozoospermicas y con alteración: en volumen (p=0,02), en la concentración espermática, N° total de espermatozoides, total de espermatozoide motiles (TEM), motilidad espermática, vitalidad y morfología normal con un valor de (p=0,00). Conclusiones:el estudio muestra que, a mayor edad, existe un incremento en las alteraciones seminales. Los parámetros seminales como volumen, concentración, vitalidad, motilidad progresiva y morfología, muestran un alto porcentaje de anormalidad. Siendo la movilidad progresiva el parámetro más afectado.

Objetives: evaluate seminal parameters in males suspected with infertility. Methods: 138 seminal samples were analyzed. The evaluation was performed using seminal analysis according to the criteria of OMS 2010. Results: the patients age was understood to be between 20 to 57 years, with a median age of 32,8± 6,7. The 61,6% of patients were normozoospermics, 9,4 % were azoospermic and 0,7% as-permic, 28,3% had one or more altered parameters (4,3% showed alteration in volume, 5,1% altered in spermatic concentration, 6,5% alter in mobility, 0,7% altered in morphology and 0,7% change in vitality, the 11% was shown to have more than one alterations). It was observed that there was a significant amount of difference between normozoospermics samples and with change: in volume (p=0,02), in spermatic concentration, total number of sperm, total sperm motile (TEM), sperm motility, vitality and normal morphology with a value of (p=0,00). Conclusions: The results of this study show that at an older age, there is an increase in the seminal alteration. The parameters of the volume, spermatic concentration, vitality, progressive motility and normal morphology, show a high percentage of abnormality, being the most affected parameter progressive motility.

Plasma surface modification of chitosan membranes: characterization and preliminary cell response studies.

Surface modification of biomaterials is a way to tailor cell responses whilst retaining the bulk properties. In this work, chitosan membranes were prepared by solvent casting and treated with nitrogen or argon plasma at 20 W for 10-40 min. AFM indicated an increase in the surface roughness as a result of the ongoing etching process. XPS and contact angle measurements showed different surface elemental compositions and higher surface free energy. The MTS test and direct contact assays with an L929 fibroblast cell line indicated that the plasma treatment improved the cell adhesion and proliferation. Overall, the results demonstrated that such plasma treatments could significantly improve the biocompatibility of chitosan membranes and thus improve their potential in wound dressings and tissue engineering applications.

Evaluación del sstado nutricional en escolares adolescentes del programa de eescolarización del niño, niña y adolecente trabajador de cochabamba 2066 / Assessment of nutritional status in children and adolescents in the school program of child and adolescent workers of Cochabamba 2006

El Programa de escolarización del niño, niña y adolescente trabajador planteó realizar una evaluación del estado nutricional de estos con el fin de ejecutar un apoyo nutricional y lograr un mayor rendimiento escolar. Este estudio es transversal, descriptivo. Se estudiaron 729 niños y niñas adolescentes trabajadores pertenecientes al programa PENNAT del área periurbana de Cochabamba. El estado nutricional se determinó a través de los indicadores Talla-Edad (T/E), Peso-Talla (P/T), y el índice de Masa Corporal (IMC). Según (T/E) el 15,9% de los niños tienen talla baja; el 39,2% talla en riesgo; 44,8% talla normal y 0,1 % talla alta. Según el (P/T) el 10 % indico desnutrición aguda (DNT 1 8,6 %, DNT 2 1,1 5 y DNT 3 0,3 %), el 12% sobrepeso y el 78% normal. El IMC indicó 12 % elevado (10 % sobrepeso y 2 % obesidad); 76,23% peso normal y 12 % de desnutrición. La presencia de sobrepeso y desnutrición, en estos niños(as) indica que existe malnutrición. Es necesario corregir esta situación, poniendo mayor énfasis en el grupo de los 7 a 10 años donde todavía es posible tener la oportunidad de una recuperación y éxito en el desarrollo físico e intelectual del niño. El presente estudio muestra que: "Debemos mejorar la calidad de los alimentos, aumentando las proteínas, vitaminas y minerales." Es por lo tanto válida la preocupación del PENNAT de mejorar la nutrición para brindar igualdad de oportunidades de estudios al niño/a y adolescente trabajador.

The Program of the boy's schollard, girl and hard-working adolescent outlined to carry out an evaluation of the nutritional state of these with the purpose of to execute a nutritional support and to achieve a bigger school yield. This study is traverse, descriptive. 729 children and adolescent girls hard-working belonging to the program PENNAT of the outlying área of Cochabamba was studied. The nutritional state was determined through the indicative Size-age (T/E), Peso-size (P/T), and the Index of Corporal Mass (IMC). According to (T/E) 15,9% of the children has low size; 39,2% carves in risk; 44,8 normal size and 0,1% carve high. According to the (P/T) 10% indicates sharp malnutrition (DNT 1 8,6%, DNT 2 1,1 5 and DNT 3 0,3%), 12% overweight and 78 normal%. The IMC indicated 12 high% (10% overweight and 2% obe-sity); 76,23% weighs normal and 12% of malnutrition. The presence of overweight and malnutrition, in these boys and girls it indicates that malnutrition exists. It is necessary to correct this situation, putting bigger emphasis in the group from the 7 to 10 years where it is still possible to have the opportunity of a recovery and success in the physical deve-lopment and the boy's intellectual. The present study shows that: We should improve the quality of the foods, increa-sing the proteins, vitamins and minerals." It is therefore valid the concern of the PENNAT of improving the nutrition to offer equality of opportunities of studies to the boys and girls hard-working adolescent.