Application of Raman spectroscopy for the determination of proteins denaturation and amino acids decomposition temperature.

Raman spectroscopy was employed to study the thermal denaturation of three different proteins, bovine serum albumin (BSA), lysozyme, ovalbumin; and the decomposition temperature of three amino acids, l-glutamine, l-cysteine, and l-alanine, all of them as lyophilized powders. All the Raman bands observed in the spectra obtained were recorded and analyzed at preset heating temperatures. The results obtained for either protein denaturation temperature TD and amino acid decomposition temperatures TM-dc, were compared with those measured by differential scanning calorimetry (DSC). The DSC and Raman results were additionally corroborated with a thermogravimetric analysis (TGA) for the case of proteins. This exercise indicated almost complete coincidence in the determination of these transition temperatures between the three techniques, evidencing the applicability of Raman spectroscopy in the study of denaturation and decomposition temperatures of proteins and amino acids.

Organochlorine Pesticides and Potentially Toxic Elements in Groundwater from a Protected Reserve in the Maya Region of Hopelchen, Mexico.

Water quality degradation by organochlorine pesticides and potentially toxic elements is of worldwide concern. This research explores groundwater conditions, regarding organochlorine pesticides and potentially toxic elements, in Hopelchen, Campeche, which is located in the buffer zone of the Calakmul Biosphere Reserve. Unfortunately, agriculture is allowed and agrochemical use is not monitored and sanctioned. Results show that Heptachlor, Endosulfan, and Dieldrin, all recognized carcinogens, had concentrations above the Mexican normative recommended values. Conversely, Cd and Ni concentrations were below recommended values. These results demonstrate that government intervention involving immediate control over agrochemical use is mandatory. Also, the results underscore the contamination of groundwater in several of the Calakmul Biosphere Reserve's buffer zones by organochlorine pesticides concentrations, posing a probable threat for local inhabitants who consume this water and use it for recreation.

Raman spectra of single walled carbon nanotubes at high temperatures: pretreating samples in a nitrogen atmosphere improves their thermal stability in air.

We present a combined experimental and theoretical study dedicated to analyzing the structural stability and chemical reactivity of single walled carbon nanotubes (SWCNTs) in the presence of air and nitrogen atmospheres in the temperature interval of 300-1000 K. The temperature dependence of the radial breathing mode (RBM) region of the Raman spectra is irreversible in the presence of air, but it is reversible up to 1000 K in a nitrogen atmosphere. Our density functional theory (DFT) calculations reveal that irreversibility is due to partial degradation of SWCNTs produced by dissociative chemical adsorption of molecular oxygen on intrinsic defects of the nanotube surface. Oxygen partially opens the nanotubes forming semi-tubes with a non-uniform diameter distribution observed by Raman scattering. In contrast, heating CNTs in a nitrogen atmosphere seems to lead to the formation of nitrogen-doped SWCNTs. Our DFT calculations indicate that in general the most common types of nitrogen doping (e.g., pyridinic, pyrrolic, and substitutional) modify the location of the RBM frequency, leading also to frequency shifts and intensity changes of the surrounding modes. However, by performing a systematic comparison between calculated and measured spectra we have been able to infer the possible adsorbed configurations adopted by N species on the nanotube surface. Interestingly, by allowing previously nitrogen-exposed SWCNTs to interact with air at different temperatures (up to 1000 K) we note that the RBM region remains nearly unperturbed, defining thus our nitrogen-pretreated SWCNTs as more appropriate carbon nanostructures for high temperature applications in realistic environments. We believe that we have implemented a post-growth heat-treatment process that improves the stability of carbon nanotubes preserving their diameter and inducing a defect-healing process of the carbon wall.

[Early clinical and radiological basic detection of congenital hip dysplasia at primary health care units]. / Detección temprana clínica y radiológica básica de la displasia congénita de cadera en unidades médicas del primer nivel de atención.

DISCUSSION: The number of cases of late congenital hip dysplasia has increased, together with its sequelae, disability and absence of early diagnosis. The problem is that there is a difference between the sensitivity and the clinical exam, and the physicians knowledge of this topic is poor. We evaluated the quality of the training provided to the primary health care staff on congenital hip dysplasia. A prospective cohort study was undertaken to study 228 physicians for 3 years. A workshop was delivered and the physicians took a pre-workshop and a post-workshop exam. Then pelvic X-rays of infants under 6 months of age were taken and the X-ray references and measurements were assessed. The statistical analysis assesses the change in the pre-workshop and post-workshop grades in both the group that participated in the workshop and the group that did not. The statistical variables used included means, standard deviation, minimum and maximum grades, and the score differences. Students t test was used to prove the statistical significance of the differences, with n-1 degrees of freedom. Thirty-one pathological hips were detected in infants under 6 months of age in the group that took the workshop. The group that received the training shows that the latter may have a positive impact since an improvement in the grades (p 0.0001) was seen after the theoretical and practical course and after the X-ray measurements. A low knowledge level was observed. The training raised the awareness of the health care staff and a progressive increase was seen in the number of infants under 6 months of age who received a timely detection.

Hay un aumento en el número de casos de displasia de cadera congénita tardía, secuelas, discapacidad y falta de diagnóstico temprano. La problemática observada es que difieren la sensibilidad y exploración clínica y los conocimientos del tema en médicos son deficientes. Se evaluó la calidad de la capacitación en displasia congénita de cadera al personal del primer nivel de la atención médica. Se realizó un estudio de cohorte prospectiva estudiando a 228 médicos por tres años; se les aplicó un examen pre- y postcurso, se dio un taller. Posteriormente, se inició la toma de radiografías de pelvis en menores de seis meses, se evaluó la referencia y la medición radiográfica. El análisis estadístico valoró el cambio de calificación obtenida en las mediciones antes y después del taller, tanto en el grupo que lo recibió como en el que no lo llevó. Se utilizaron promedios, desviación estándar, mínimo y máximo para describir las calificaciones, así como para las diferencias de puntajes. Para probar la significancia en las diferencias, se utilizó «t¼ de Student, con n-1 grados de libertad. Se detectaron 31 caderas patológicas en menores de seis meses de vida con el taller. El grupo capacitado reflejó que el curso podría tener impacto positivo al mejorar significativamente la calificación (p 0.0001) posterior al curso tanto teórico como práctico y la medición radiográfica. Se evidenció un bajo conocimiento. La capacitación con el taller sensibilizó al personal médico y se observó un número progresivo de pacientes menores de seis meses con una detección oportuna.

Evaluation of the possible inclusion of certain fish species in chronic kidney disease diets based on their adverse and beneficial nutrient ratios.

The goal of this study was to quantify the adverse (phosphorus, protein, sodium, potassium and cholesterol) and beneficial [n-3 fatty acids: eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA); vitamins D(3) and E] nutrients in 14 fish species in order to evaluate their inclusion in chronic kidney disease (CKD) diets. Using AOAC methods, we obtained the following results per 100 g of fish: 50.86-227.52 mg phosphorus, 14.7-30.6 g protein and 3.83-1667.35 mg EPA+DHA. CKD patients with protein or phosphorus restrictions should avoid broadbill swordfish, black bullhead and spotted scorpionfish. However, patients may include parrot sand bass, black bullhead, broadbill swordfish, longjaw leatherjacket, oilfish, Atlantic tripletail, spotted scorpionfish and round herring in their diets based on the (P)/(EPA+DHA) ratios of these fish. Some fish species may be included in CKD diets because of their high biological value protein content - associated with cardiovascular and renal protective nutrients (EPA+DHA) - and low P, Na, K and cholesterol content, their consumption by CKD patients should be encouraged.

The effect of glucocorticoids on sex steroid synthesis in cultured Taenia crassiceps Wake Forest University (WFU) cysticerci.

We have shown previously that cultured Taenia crassiceps Wake Forest University (WFU) and Taenia solium cysticerci, as well as the adult worms, synthesize sex steroid hormones from [3H]steroid precursors and that androgens and oestrogens influence the in vitro development of the parasites. Glucocorticoids (GCs) are used to control the inflammation caused by T. solium cysticerci in the brain. These steroids stimulate oestrogen synthesis in several tissues. Since there is no information on the effect of GC on the endocrine function of cysticerci, we investigated the effect of natural and synthetic GCs on the synthesis of oestrogens in cultured T. crassiceps WFU cysticerci. The cysticerci were obtained from the peritoneal cavity of infected female BALB/c mice; the cysts were washed extensively and pre-cultured in Dulbecco's Modified Eagle's Medium (DMEM) plus antibiotics for 5 days. The parasites were further cultured with different doses of corticosterone, dexamethasone or the vehicle for 5 days. [3H]Dehydroepiandrosterone (3H-DHEA) was added to the media and the cysticerci were further incubated for 6 or 24 h. Media were then removed and the steroids ether-extracted. Aliquots of the media were seeded on silica gel plates and developed in solvent systems. Parasites incubated in the presence of 3H-DHEA synthesized [3H]androstenediol, [3H]testosterone and [3H]17ß-oestradiol ([3H]17ß-E2). The addition of 100 nm or higher corticosterone doses to the media increased [3H]17ß-E2 synthesis fourfold after 24 h. Dexamethasone also increased [3H]17ß-E2 synthesis. The experiments presented here show for the first time that corticosterone and the synthetic GC dexamethasone modulate the synthesis of oestrogens by cysticerci.

[Quality of life of patients after periprosthetic hip fracture surgery]. / Calidad de vida en los pacientes postoperados de fracturas periprotésicas de cadera.

INTRODUCTION: The quality of life of patients with periprosthetic fracture is complex; it interacts with the severity of the lesion, their independence level, and available resources, all of which could cause alterations secondary to their condition. OBJECTIVE: To know the quality of life and clinical course of patients after periprosthetic hip fracture surgery. MATERIAL AND METHODS: Patients with periprosthetic hip fracture were assessed. Physical exam was performed and the SF-36 questionnaire was applied. RESULTS: A total of 15 patients were included, 8 (53.3%) females and 7 (46.7%) males, with mean age 74 years (SD 12.51). Concerning underlying conditions, 5 patients had none (33.3%), one had hypertension (6.7%), one had a neoplasia (epidermoid), and 8 had more than one underlying condition. A predictive variable model was designed. In the overall score a 75.6% positive correlation was found, and a 57.2% determination coefficient. There was no statistical significance (p = 0.162). The same variables as in the previous model were included. Correlation was 0.678 and determination 45.9%, without statistical significance, p = 0.332. CONCLUSIONS: Patients reported feeling fair from the perspective of their overall health, physical function, physical role, emotional role, and social function; mental health wise, 50% reported feeling calm and full of life, and 50% reported anxiety and fear.

[Renal patient's diet: Can fish be included?]. / La dieta del paciente renal: ¿Se puede incluir pescado?

INTRODUCTION: Medical and nutritional treatment for renal disease, now a major public health issue, is highly complicated. Nutritional therapy must seek to retard renal dysfunction, maintain an optimal nutritional status and prevent the development of underlying pathologies. OBJECTIVE: To analyze ten fish species to identify those that, because of their low phosphorus content, high biological value protein and elevated n-3 fatty acids EPA and DHA, could be included in renal patient's diet. MATERIALS AND METHODS: The following fish species (Litte tunny, Red drum, Spotted eagleray, Escolar, Swordfish, Big-scale pomfret, Cortez flounder, Largemouth blackbass, Periche mojarra, Florida Pompano) were analyzed according to the AOAC and Keller techniques to determine their protein, phosphorus, sodium, potassium, cholesterol, vitamins D(3) and E, and n-3 EPA+DHA content. These results were used to calculate relations between nutrients. RESULTS: The protein in the analyzed species ranged from 16.5 g/100 g of fillet (Largemouth black bass) to 27.2 g/100 g (Red drum); the lowest phosphorus value was 28.6 mg/100 g (Periche mojarra) and the highest 216.3 mg/100 g (Spotted eagle ray). 80% of the fish presented > 100 mg EPA + DHA in 100 g of fillet. By its Phosphorus/gProtein ratio, Escolar and Swordfish could not be included in the renal diet; Little tunny, Escolar, Big-scale pomfret, Largemouth black-bass, Periche mojarra and Florida Pompano presented a lower Phosphorus/EPA + DHA ratio. CONCLUSIONS: Florida pompano is the most recommended specie for renal patients, due to its optimal nutrient relations. However, all analyzed species, except Escolar and Swordfish, could be included in renal diets.

Historia de la ventilación mecánica / Children's Hospital "Ricardo Gutiérrez"

Siglos de aciertos y errores en el entendimiento de la fisiología pulmonar fueron la base para el desarrollo de los primeros aparatos de ventilación artificial. En los pasados cien años, desde que la humanidad avanzó hacia el sostén artificial del pulmón, el progreso fue vertiginoso. La asistencia respiratoria mecánica a presión negativa, inicialmente, dominó la tecnología de la época, y los "pulmones de acero" en las graves epidemias de poliomielitis, fueron los protagonistas. Pronto la historia demostró la infalibilidad de aquellos. En la ciudad de Copenhague, en Dinamarca, los sucesos relacionados con la epidemia de poliomielitis de 1952, modificaron la historia, y la asistencia respiratoria mecánica a presión positiva empezó a ganar la batalla en la insuficiencia respiratoria. Este trabajo intenta contar, a través de las palabras y anécdotas de muchos de los personajes que vivieron esta historia, los sucesos fundamentales que llevaron a la comprensión y utilización de la ventilación artificial, tal como la conocemos hoy en día. (AU)

Centuries of strengths and weaknesses in the understanding of pulmonary physiology, were the basis for the development of the first devices for artificial ventilation. In the last 100 years, since mankind advanced towards the artificial support of the lung, the progress was rapid. Negative pressure mechanical ventilation, initially dominated the technology of the era, and the "iron lungs" were the protagonists during the severe epidemics of poliomyelitis. Soon the history proved their infallibility. In the city of Copenhagen, Denmark, the events associated with the polio epidemic of 1952 changed history, and positive pressure mechanical ventilation began winning the battle in respiratory failure. Through the words and experiences of many of the characters who lived this story, this work attempts to tell the fundamental events that led to the understanding and use of artificial ventilation as we know it today.(AU)

Labor force growth and the environment in Costa Rica.

PIP: The introduction to this report of a study that examines the potential environmental impacts of labor force growth (LFG) in Costa Rica under LFG scenarios notes that LFG is an economically critical aspect of population growth that can affect the environment by expanding the economy's production possibilities frontier and/or by increasing consumption. The introduction also explains why Costa Rica is ideal for this study and identifies the study as unique because it constructs a computable general equilibrium (CGE) model using 10 environmental indicators and because it models uncertainty regarding the values of the economic parameters. The report continues by reviewing the literature linking population and environmental issues; detailing the CGE model; discussing the 10 environmental indicators (deforestation, erosion, pesticide use, overfishing, hazardous wastes, inorganic wastes, organic wastes, greenhouse gas emissions, air pollution, and water/sewer usage) used in the model; and explaining the method used to simulate the impacts of LFG. The major conclusions that emerged from the results of this study are that 1) the economy-wide impacts of LFG (and, thus, population growth) on the environment are important and vary significantly according to the amounts of physical and human capital present in the labor force and 2) the impacts of LFG vary substantially among environmental indicators.^ieng