Psychological and Cognitive Factors that Influence Post-Exercise Energy Intake in Normal Weight and Overweight Sedentary Males

The primary purpose of this study was to evaluate the effects of a single bout of moderate-intensity exercise on acute (ad libitum lunch) post-exercise energy intake (PE-EI) and 12-hour energy intake in normal-weight and overweight sedentary males. Accuracy in estimating energy intake (EI) and energy expenditure (EE), solid vs. liquid carbohydrate intake, mood, and perceived hunger were also assessed. The study consisted of two conditions, exercise and rest, with each subject participating in each condition, in a counterbalanced-crossover design on two days. The participants were randomly assigned to either the exercise or resting (seated) control condition on the first day of the experiment, and then the condition was reversed on the second day. Exercise consisted of walking on a treadmill at moderate-intensity for 60 minutes. Eighty males, mean age 30+8 years were categorized into five groups according to weight status (overweight/normal-weight), dietary restraint status (high/low), and dieting status (yes/no). The main effects of condition and group, and the interaction were not significant for acute (lunch) or 12-hour PE-EI. Overall, participants estimated EE for exercise at 46% higher than actual exercise EE, and they estimated EE for rest by 45% lower than actual resting EE. Participants significantly underestimated EI at lunch on both the exercise and rest days by 43% and 44%, respectively. Participants with high restraint were significantly better at estimating EE on the exercise day, and better at estimating EI on the rest day. Mood, perceived hunger, and solid vs. liquid carbohydrate intake were not influenced by dietary restraint, weight, or dieting status. In conclusion, a single bout of moderate-intensity exercise did not influence PE-EI in sedentary males in reference to dietary restraint, weight, and dieting status. Results also suggested that among sedentary males, there is a general inability to accurately estimate calories for moderate-intensity physical activity and EI. Inaccurate estimates of EE and EI have the potential to influence how males manage their weight.

Glycated hemoglobin, body weight and blood pressure in type 2 diabetes patients initiating dapagliflozin treatment in primary care:a retrospective study

Introduction - The present study aimed to describe characteristics of patients with type 2 diabetes (T2D) in UK primary care initiated on dapagliflozin, post-dapagliflozin changes in glycated hemoglobin (HbA1c), body weight and blood pressure, and reasons for adding dapagliflozin to insulin. Methods - Retrospective study of patients with T2D in the Clinical Practice Research Datalink with first prescription for dapagliflozin. Patients were included in the study if they: (1) had a first prescription for dapagliflozin between November 2012 and September 2014; (2) had a Read code for T2D; (3) were registered with a practice for at least 6 months before starting dapagliflozin; and (4) remained registered for at least 3 months after initiation. A questionnaire ascertained reason(s) for adding dapagliflozin to insulin. Results - Dapagliflozin was most often used as triple therapy (27.7%), dual therapy with metformin (25.1%) or added to insulin (19.2%). Median therapy duration was 329 days [95% confidence interval (CI) 302–361]. Poor glycemic control was the reason for dapagliflozin initiation for 93.1% of insulin-treated patients. Avoiding increases in weight/body mass index and insulin resistance were the commonest reasons for selecting dapagliflozin versus intensifying insulin. HbA1c declined by mean of 9.7 mmol/mol (95% CI 8.5–10.9) (0.89%) 14–90 days after starting dapagliflozin, 10.2 mmol/mol (95% CI 8.9–11.5) (0.93%) after 91–180 days and 12.6 mmol/mol (95% CI 11.0–14.3) (1.16%) beyond 180 days. Weight declined by mean of 2.6 kg (95% CI 2.3–2.9) after 14–90 days, 4.3 kg (95% CI 3.8–4.7) after 91–180 days and 4.6 kg (95% CI 4.0–5.2) beyond 180 days. In patients with measurements between 14 and 90 days after starting dapagliflozin, systolic and diastolic blood pressure decreased by means of 4.5 (95% CI −5.8 to −3.2) and 2.0 (95% CI −2.9 to −1.2) mmHg, respectively from baseline. Similar reductions in systolic and diastolic blood pressure were observed after 91–180 days and when follow-up extended beyond 180 days. Results were consistent across subgroups. Conclusion - HbA1c, body weight and blood pressure were reduced after initiation of dapagliflozin in patients with T2D in UK primary care and the changes were consistent with randomized clinical trials.

Enzymatic Polymerization of High Molecular Weight DNA

The use of DNA as a polymeric building material transcends its function in biology and is exciting in bionanotechnology for applications ranging from biosensing, to diagnostics, and to targeted drug delivery. These applications are enabled by DNA’s unique structural and chemical properties, embodied as a directional polyanion that exhibits molecular recognition capabilities. Hence, the efficient and precise synthesis of high molecular weight DNA materials has become key to advance DNA bionanotechnology. Current synthesis methods largely rely on either solid phase chemical synthesis or template-dependent polymerase amplification. The inherent step-by-step fashion of solid phase synthesis limits the length of the resulting DNA to typically less than 150 nucleotides. In contrast, polymerase based enzymatic synthesis methods (e.g., polymerase chain reaction) are not limited by product length, but require a DNA template to guide the synthesis. Furthermore, advanced DNA bionanotechnology requires tailorable structural and self-assembly properties. Current synthesis methods, however, often involve multiple conjugating reactions and extensive purification steps.

The research described in this dissertation aims to develop a facile method to synthesize high molecular weight, single stranded DNA (or polynucleotide) with versatile functionalities. We exploit the ability of a template-independent DNA polymerase−terminal deoxynucleotidyl transferase (TdT) to catalyze the polymerization of 2’-deoxyribonucleoside 5’-triphosphates (dNTP, monomer) from the 3’-hydroxyl group of an oligodeoxyribonucleotide (initiator). We termed this enzymatic synthesis method: TdT catalyzed enzymatic polymerization, or TcEP.

Specifically, this dissertation is structured to address three specific research aims. With the objective to generate high molecular weight polynucleotides, Specific Aim 1 studies the reaction kinetics of TcEP by investigating the polymerization of 2’-deoxythymidine 5’-triphosphates (monomer) from the 3’-hydroxyl group of oligodeoxyribothymidine (initiator) using in situ 1H NMR and fluorescent gel electrophoresis. We found that TcEP kinetics follows the “living” chain-growth polycondensation mechanism, and like in “living” polymerizations, the molecular weight of the final product is determined by the starting molar ratio of monomer to initiator. The distribution of the molecular weight is crucially influenced by the molar ratio of initiator to TdT. We developed a reaction kinetics model that allows us to quantitatively describe the reaction and predict the molecular weight of the reaction products.

Specific Aim 2 further explores TcEP’s ability to transcend homo-polynucleotide synthesis by varying the choices of initiators and monomers. We investigated the effects of initiator length and sequence on TcEP, and found that the minimum length of an effective initiator should be 10 nucleotides and that the formation of secondary structures close to the 3’-hydroxyl group can impede the polymerization reaction. We also demonstrated TcEP’s capacity to incorporate a wide range of unnatural dNTPs into the growing chain, such as, hydrophobic fluorescent dNTP and fluoro modified dNTP. By harnessing the encoded nucleotide sequence of an initiator and the chemical diversity of monomers, TcEP enables us to introduce molecular recognition capabilities and chemical functionalities on the 5’-terminus and 3’-terminus, respectively.

Building on TcEP’s synthesis capacities, in Specific Aim 3 we invented a two-step strategy to synthesize diblock amphiphilic polynucleotides, in which the first, hydrophilic block serves as a macro-initiator for the growth of the second block, comprised of natural and/or unnatural nucleotides. By tuning the hydrophilic length, we synthesized the amphiphilic diblock polynucleotides that can self-assemble into micellar structures ranging from star-like to crew-cut morphologies. The observed self-assembly behaviors agree with predictions from dissipative particle dynamics simulations as well as scaling law for polyelectrolyte block copolymers.

In summary, we developed an enzymatic synthesis method (i.e., TcEP) that enables the facile synthesis of high molecular weight polynucleotides with low polydispersity. Although we can control the nucleotide sequence only to a limited extent, TcEP offers a method to integrate an oligodeoxyribonucleotide with specific sequence at the 5’-terminus and to incorporate functional groups along the growing chains simultaneously. Additionally, we used TcEP to synthesize amphiphilic polynucleotides that display self-assemble ability. We anticipate that our facile synthesis method will not only advance molecular biology, but also invigorate materials science and bionanotechnology.

Foraminifera Mg/Ca, test weight and XDX for sediment core WIND28K

A record of deep-sea calcite saturation (D[CO3**-2]), derived from X-ray computed tomography-based foraminifer dissolution index, XDX, was constructed for the past 150 ka for a core from the deep (4157 m) tropical western Indian Ocean. G. sacculifer and N. dutertrei recorded a similar dissolution history, consistent with the process of calcite compensation. Peaks in calcite saturation (~15 µmol/kg higher than the present-day value) occurred during deglaciations and early in MIS 3. Dissolution maxima coincided with transitions to colder stages. The mass record of G. sacculifer better indicated preservation than did that of N. dutertrei or G. ruber. Dissolution-corrected Mg/Ca-derived SST records, like other SST records from marginal Indian Ocean sites, showed coolest temperatures of the last 150 ka in early MIS 3, when mixed layer temperatures were ~4°C lower than present SST. Temperatures recorded by N. dutertrei showed the thermocline to be ~4°C colder in MIS 3 compared to the Holocene (8 ka B.P.).

Geometric versus Model Predictive Control based guidance algorithms for fixed-wing UAVs in the presence of very strong wind fields.

The recent years have witnessed increased development of small, autonomous fixed-wing Unmanned Aerial Vehicles (UAVs). In order to unlock widespread applicability of these platforms, they need to be capable of operating under a variety of environmental conditions. Due to their small size, low weight, and low speeds, they require the capability of coping with wind speeds that are approaching or even faster than the nominal airspeed. In this thesis, a nonlinear-geometric guidance strategy is presented, addressing this problem. More broadly, a methodology is proposed for the high-level control of non-holonomic unicycle-like vehicles in the presence of strong flowfields (e.g. winds, underwater currents) which may outreach the maximum vehicle speed. The proposed strategy guarantees convergence to a safe and stable vehicle configuration with respect to the flowfield, while preserving some tracking performance with respect to the target path. As an alternative approach, an algorithm based on Model Predictive Control (MPC) is developed, and a comparison between advantages and disadvantages of both approaches is drawn. Evaluations in simulations and a challenging real-world flight experiment in very windy conditions confirm the feasibility of the proposed guidance approach.

Large-Scale Controlled-Condition Experiment to Evaluate Light Weight Deflectometers for Modulus Determination and Compaction Quality Assurance of Unbound Pavement Materials

Compaction control using lightweight deflectometers (LWD) is currently being evaluated in several states and countries and fully implemented for pavement construction quality assurance (QA) by a few. Broader implementation has been hampered by the lack of a widely recognized standard for interpreting the load and deflection data obtained during construction QA testing. More specifically, reliable and practical procedures are required for relating these measurements to the fundamental material property—modulus—used in pavement design. This study presents a unique set of data and analyses for three different LWDs on a large-scale controlled-condition experiment. Three 4.5x4.5 m2 test pits were designed and constructed at target moisture and density conditions simulating acceptable and unacceptable construction quality. LWD testing was performed on the constructed layers along with static plate loading testing, conventional nuclear gauge moisture-density testing, and non-nuclear gravimetric and volumetric water content measurements. Additional material was collected for routine and exploratory tests in the laboratory. These included grain size distributions, soil classification, moisture-density relations, resilient modulus testing at optimum and field conditions, and an advanced experiment of LWD testing on top of the Proctor compaction mold. This unique large-scale controlled-condition experiment provides an excellent high quality resource of data that can be used by future researchers to find a rigorous, theoretically sound, and straightforward technique for standardizing LWD determination of modulus and construction QA for unbound pavement materials.

Quantification of the human postural control system to perturbations

Human standing posture is inherently unstable. The postural control system (PCS), which maintains standing posture, is composed of the sensory, musculoskeletal, and central nervous systems. Together these systems integrate sensory afferents and generate appropriate motor efferents to adjust posture. The PCS maintains the body center of mass (COM) with respect to the base of support while constantly resisting destabilizing forces from internal and external perturbations. To assess the human PCS, postural sway during quiet standing or in response to external perturbation have frequently been examined descriptively. Minimal work has been done to understand and quantify the robustness of the PCS to perturbations. Further, there have been some previous attempts to assess the dynamical systems aspects of the PCS or time evolutionary properties of postural sway. However those techniques can only provide summary information about the PCS characteristics; they cannot provide specific information about or recreate the actual sway behavior. This dissertation consists of two parts: part I, the development of two novel methods to assess the human PCS and, part II, the application of these methods. In study 1, a systematic method for analyzing the human PCS during perturbed stance was developed. A mild impulsive perturbation that subjects can easily experience in their daily lives was used. A measure of robustness of the PCS, 1/MaxSens that was based on the inverse of the sensitivity of the system, was introduced. 1/MaxSens successfully quantified the reduced robustness to external perturbations due to age-related degradation of the PCS. In study 2, a stochastic model was used to better understand the human PCS in terms of dynamical systems aspect. This methodology also has the advantage over previous methods in that the sway behavior is captured in a model that can be used to recreate the random oscillatory properties of the PCS. The invariant density which describes the long-term stationary behavior of the center of pressure (COP) was computed from a Markov chain model that was applied to postural sway data during quiet stance. In order to validate the Invariant Density Analysis (IDA), we applied the technique to COP data from different age groups. We found that older adults swayed farther from the centroid and in more stochastic and random manner than young adults. In part II, the tools developed in part I were applied to both occupational and clinical situations. In study 3, 1/MaxSens and IDA were applied to a population of firefighters to investigate the effects of air bottle configuration (weight and size) and vision on the postural stability of firefighters. We found that both air bottle weight and loss of vision, but not size of air bottle, significantly decreased balance performance and increased fall risk. In study 4, IDA was applied to data collected on 444 community-dwelling elderly adults from the MOBILIZE Boston Study. Four out of five IDA parameters were able to successfully differentiate recurrent fallers from non-fallers, while only five out of 30 more common descriptive and stochastic COP measures could distinguish the two groups. Fall history and the IDA parameter of entropy were found to be significant risk factors for falls. This research proposed a new measure for the PCS robustness (1/MaxSens) and a new technique for quantifying the dynamical systems aspect of the PCS (IDA). These new PCS analysis techniques provide easy and effective ways to assess the PCS in occupational and clinical environments.

The effects of PVP(FE(III)) catalyst and polymer molecular weight on gene delivery via biodegradable crosslinked polyethylenimine

Human gene therapy has faced many setbacks due to the immunogenicity and oncogenity of viruses. Safe and efficient alternative gene delivery vehicles are needed to implement gene therapy in clinical practice. Polymeric vectors are an attractive option due to their availability, simple chemistry, and low toxicity and immunogenicity. Our group has previously reported biodegradable polyethylenimines (PEI) that show high transfection efficiency and low toxicity by cross-linking 800 Da PEI with diacrylate cross-linkers using Michael addition. However, the synthesis was difficult to control, inconsistent, and resulted in polymers with a narrow range of molecular weights. In the present work, we utilized a heterogenous PVP(Fe(III)) catalyst to provide a more controllable PEI crosslinking reaction and wider range of biodegradable PEIs. The biodegradable PEIs reported here have molecular weights ranging from 1.2 kDa to 48 kDa, are nontoxic in MDA-MB-231 cells, and show low toxicity in HeLa cells. At their respective optimal polymer:DNA ratios, these biodegradable PEIs demonstrated about 2-5-fold higher transfection efficiency and 2-7-fold higher cellular uptake, compared unmodified 25 kDa PEI. The biodegradable PEIs show similar DNA condensation properties as unmodified PEI but more readily unpackage DNA, based on ethidium bromide exclusion and heparan sulfate competitive displacement assays, which could contribute to their improved transfection efficiency. Overall, the synthesis reported here provides a more robust, controlled reaction to produce cross-linked biodegradable PEIs that show enhanced gene delivery, low toxicity, and high cellular uptake and can potentially be used for future in vivo studies.

CONTROL OF SIZE AND MAGNETIC PROPERTIES OF CARBOXYL-FUNCTIONALIZED MAGNETITE PARTICLES: SYNTHESIS PROCEDURES, CHARACTERIZATIONS, AND APPLICATIONS

Magnetic nanoparticles (MNPs) are known for the unique properties conferred by their small size and have found wide application in food safety analyses. However, their high surface energy and strong magnetization often lead to aggregation, compromising their functions. In this study, iron oxide magnetic particles (MPs) over the range of nano to micro size were synthesized, from which particles with less aggregation and excellent magnetic properties were obtained. MPs were synthesized via three different hydrothermal procedures, using poly (acrylic acid) (PAA) of different molecular weight (Mw) as the stabilizer. The particle size, morphology, and magnetic properties of the MPs from these synthesis procedures were characterized and compared. Among the three syntheses, one-step hydrothermal synthesis demonstrated the highest yield and most efficient magnetic collection of the resulting PAA-coated magnetic microparticles (PAA-MMPs, >100 nm). Iron oxide content of these PAA-MMPs was around 90%, and the saturation magnetization ranged from 70.3 emu/g to 57.0 emu/g, depending on the Mw of PAA used. In this approach, the particles prepared using PAA with Mw of 100K g/mol exhibited super-paramagnetic behavior with ~65% lower coercivity and remanence compared to others. They were therefore less susceptible to aggregation and remained remarkably water-dispersible even after one-month storage. Three applications involving PAA-MMPs from one-step hydrothermal synthesis were explored: food proteins and enzymes immobilization, antibody conjugation for pathogen capture, and magnetic hydrogel film fabrication. These studies demonstrated their versatile functions as well as their potential applications in the food science area.

Impact of weight reduction program on serum alanine aminotransferase activity and immunologic response in obese hepatitis B patients.

Background: Globally, chronic B viral hepatitis (HBV) is a major health problem. Obesity is a common problem among patients with HBV. Several studies have reported that obesity is an important risk factor that alters immune system response in individuals with no underlying cause of liver disease. However, there is a strong association between BMI and the human immune system among HBV patients. Objective: This study was to examine the correlation between body mass index, serum alanine aminotransferase activity (ALT) and immunologic response in obese hepatitis B patients. Material and methods: One hundred fifty male patients with chronic hepatitis B virus, their age ranged from 30 to 45 (38.64 ± 7.12) years and their BMI ranged from 30-35 kg/m2. All Subjects were included in two groups: The first group received weight reduction program in the form of treadmill aerobic exercises in addition to diet control whereas the second group received no therapeutic intervention. Parameters of serum alanine aminotransferase (ALT), CD3, CD4 and CD8 were quantified; Leukocyte, differential counts and body mass index (BMI) were measured before and after 3 months at the end of the study. Results: There was a 24.7%, 36.8%, 30.8%, 40.7%, 28.6%, 25.9%, 33.3% and 14.3 % reduction in mean values of alanine aminotransferase (ALT), white blood cells, total neutrophil count, monocytes, CD3, CD4 ,CD8 and BMI respectively in group (A) at the end of the study. In addition, there were significant differences between mean levels of the investigated parameters in groups. Conclusion: Based on our findings, weight loss modulates serum alanine aminotransferase and immune system parameters of patients with hepatitis B virus infection.

Spatiotemporal neuromodulation therapies engaging muscle synergies improve motor control after spinal cord injury.

Electrical neuromodulation of lumbar segments improves motor control after spinal cord injury in animal models and humans. However, the physiological principles underlying the effect of this intervention remain poorly understood, which has limited the therapeutic approach to continuous stimulation applied to restricted spinal cord locations. Here we developed stimulation protocols that reproduce the natural dynamics of motoneuron activation during locomotion. For this, we computed the spatiotemporal activation pattern of muscle synergies during locomotion in healthy rats. Computer simulations identified optimal electrode locations to target each synergy through the recruitment of proprioceptive feedback circuits. This framework steered the design of spatially selective spinal implants and real-time control software that modulate extensor and flexor synergies with precise temporal resolution. Spatiotemporal neuromodulation therapies improved gait quality, weight-bearing capacity, endurance and skilled locomotion in several rodent models of spinal cord injury. These new concepts are directly translatable to strategies to improve motor control in humans.

A randomised controlled trial comparing weight adjusted dose versus fixed dose prophylactic phenylephrine infusion on maintaining systolic blood pressure during caesarean section under spinal anaesthesia.

Background: Spinal anaesthesia is the standard of care for elective caesarean delivery. It has advantages over general anaesthesia. However the sympathetic blockade induced by spinal anaesthesia results in an 80 percent incidence of hypotension without prophylactic management. Current evidence supports co-loading with intravenous fluids in conjunction with the use of vasopressors as the most effective way to prevent and treat the hypotension. Phenylephrine is the accepted vasopressor of choice in the parturient. A prophylactic phenylephrine infusion combined with a fluid co-load is proven to be an effective and safe method of maintaining maternal hemodynamic stability. While most published studies have assessed the effectiveness of a prophylactic phenylephrine fixed dose infusion, few studies have assessed the effect of a prophylactic phenylephrine weight adjusted dose infusion on maintaining maternal hemodynamic stability following spinal anesthesia for a cesarean delivery. Objective: To compare the incidence of hypotension between women undergoing elective caesarean section under spinal anaesthesia, receiving prophylactic phenylephrine infusion at a fixed dose of 37.5 micrograms per minute versus a weight adjusted dose of 0.5 micrograms per kilogram per minute. Methods: One hundred and eight patients scheduled for non-urgent caesarean section under spinal anaesthesia were randomized into 2 groups; control group and intervention group using a computer generated table of numbers. Control group; Received prophylactic phenylephrine fixed dose infusion at 37.5 micrograms per minute. Intervention group; Received prophylactic phenylephrine weight adjusted dose infusion at 0.5 micrograms per kilogram per minute Results: The two groups had similar baseline characteristics in terms of ; Age, sex, weight and height. There was a 35.2% incidence of hypotension in the fixed dose group and an 18.6% incidence of hypotension in the weight adjusted dose group. This difference was found to be of borderline statistical significance p-value 0.05, and the difference in the incidence rates between the two groups was found to be statistically significant p= 0.03. The difference in the incidence of reactive hypertension and bradycardia between the two groups was not statistically significant: p-value of 0.19 for reactive hypertension and p-value of 0.42 for the incidence of bradycardia. There was also no statistically significant difference in the use of phenylephrine boluses, use of atropine, intravenous fluid used and the number of times the infusion was stopped. Conclusion: Among this population, the incidence of hypotension was significantly less in the weight adjusted dose group than in the fixed dose group. There was no difference in the number of physician interventions required to keep the blood pressure within 20% of baseline, and no difference in the proportion of reactive hypertension or bradycardia between the two groups. Administering prophylactic phenylephrine infusion at a weight adjusted dose of 0.5 micrograms per kilogram per minute results in a lower incidence of hypotension compared to its administration at a fixed dose of 37.5 micrograms per minute.

Impact of weight loss on oxidative stress and inflammatory cytokines in obese type 2 diabetic patients.

Background: Type 2 diabetes mellitus is associated with abnormal markers of inflammatory cytokines and oxidative stress markers. Although, these abnormalities could be modulated with weight reduction; there is limitation in clinical studies that have addressed the beneficial effects of weight reduction in modulating biomarkers of inflammatory cytokines and oxidative stress for obesity associated with type 2 diabetes mellitus. Objective: This study was designed to detect the effects of weight loss on the inflammatory cytokines, oxidative stress markers in obese type 2 diabetic patients. Material and Methods: Eighty obese patients with type 2 diabetes mellitus, their age ranged from 35-57 years and their body mass index ranged from 31-35 kg/m2 were equally assigned into 2 groups: the weight reduction group received aerobic exercises, diet regimen, where as the control group received medical treatment only for 12 weeks. Results: The mean values of body mass index (BMI), tumor necrosis factor–alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (sCRP), conjugated dienes (CD) and malondialdehyde (MDA) were significantly decreased, while the mean values of glutathione peroxidase (GPx), superoxide dismutase (SOD) and glutathione (GSH) were significantly increased in patients of group (A), while changes were not significant in group (B). Also, there were significant differences between mean levels of the investigated parameters in group (A) and group (B) at the end of the study. Conclusion: Weight loss ameliorates inflammatory cytokines and oxidative stress markers in obese type 2 diabetic patients.

Deficiencias minerales en bovinos para carne: diagnóstico, caracterización y control

La demanda de una producción de alimentos cada vez mayor a nivel mundial sumado a la tecnificación y al ritmo acelerado del progreso de las explotaciones agropecuarias actuales hacen que el ganado deba soportar elevadas presiones de producción aumentando los requerimientos de nutrientes. Este es el caso de los minerales considerados actualmente elementos esenciales para los animales, aunque tradicionalmente fueron definidos como los nutrientes pobres de la nutrición y alimentación animal. Actualmente se ha demostrado con evidencia clínica y productiva, el importante rol metabólico de los minerales en el animal sano y productivo, como también se ha definido qué elemento mineral y porcentaje del mismo es requerido para el normal funcionamiento del organismo. Los macro-minerales (calcio, magnesio, fósforo, sodio, potasio, cloro y azufre) y los oligo-minerales (cobre, zinc, hierro, selenio, cobalto, iodo, manganeso, molibdeno y cromo) son elementos esenciales y necesarios para transformar la proteína y la energía de los alimentos en componentes del organismo o en productos animales como leche, carne, crías, piel, lana. Además, ayudan al organismo a combatir las enfermedades, manteniendo al animal en buen estado de salud. Se ha considerado a los minerales como el tercer grupo limitante en la nutrición animal, siendo a su vez, el que mayor potencial y menor costo tiene para incrementar la producción del ganado. Los minerales desempeñan funciones tan importantes como ser constituyentes de la estructura ósea y dental, de tejidos blandos y líquidos corporales. Están involucrados en el funcionamiento celular, siendo activadores de más de trescientas enzimas, constituyentes esenciales de vitaminas, hormonas y pigmentos respiratorios y facilitando la actividad de los microorganismos del rumen. Cuando el aporte de minerales en la ración no es el adecuado en calidad y/o cantidad se originan las deficiencias minerales, encuadradas dentro de las enfermedades metabólicas o enfermedades de la producción. Estas han sido informadas en casi todo el mundo y son responsables de importantes pérdidas económicas en los rodeos de bovinos para carne. Las deficiencias y/o desequilibrios minerales pueden causar los siguientes trastornos en los animales: bajo porcentaje de parición, mayor número de servicios por concepción, abortos, retenciones placentarias, incremento del intervalo entre partos, baja producción de leche, menor peso al nacimiento y al destete, menor porcentaje de destete, menor ganancia de peso, mayor incidencia de enfermedades infecciosas, fracturas espontáneas, diarrea, deformación de huesos y mortandad. Así cobra importancia el diagnóstico mediante el análisis de la sangre de los animales, del pasto y el agua que consumen y la caracterización de estas deficiencias en primarias o secundarias con el objetivo de poder realizar un control de las mismas mediante un adecuado plan de suplementación mineral acorde a las necesidades de los distintos establecimientos agropecuarios.

Factors associated with obesity in Brazilian children enrolled in the School Health Program: a case-control study

Case-control studies evaluating the factors associated with childhood obesity are scarce in Brazil. We aimed to analyze the factors associated with obesity in Brazilian schoolchildren enrolled in the School Health Program.A case-control study was conducted on 80 schoolchildren aged 7 to 9 years, 40 of them obese and 40 of normal weight according to the cut-off points established by the World Health Organization (2007). Weight, height and waist circumference were obtained. Socioeconomic, demographic, health, eating behavior and lifestyle data were collected by applying a questionnaire to the person responsible and by determining his/her nutritional status. A binary unconditional logistic regression model (univariate and multivariate) was used for data analysis. The prevalence of obesity was 7.21%. The final model showed that duration of breast-feeding ≥6 months of age (OR 5.3; 95% CI: 1.3-22.1), excess weight of the person responsible (OR 7.1; 95% CI: 1.2-40.2), a sedentary level of physical activity (OR 4.1; 95% CI: 1.115.5), and fast chewing (OR 7.4; 95% CI: 2.1-26.9) were significantly associated with childhood obesity. The factors associated with obesity in schoolchildren were duration of breast-feeding ≥6 months, persons responsible with excess weight, and sedentary children who chew fast. The present study contributes information to be used for the health actions planned by the School Health Program.