RESUMEN
Efficient separation and storage of gas streams involving light hydrocarbons is essential for industrial applications. These hydrocarbons are widely used as energy resources and/or chemical raw materials in various chemical reactions. Here, we focus on the separation of acetylene from methane and carbon dioxide. The separation of acetylene from carbon dioxide is, in particular, challenging due to the similar kinetic diameters and boiling points of the molecules. In recent years, considerable progress has been made in adsorption-based separations using porous metal-organic frameworks (MOFs). Most reported studies are experimental. We present a computational study on these gas separations using a variety of MOFs. This allows investigation of the competitive gas adsorption, which is experimentally challenging, as well as understanding the adsorption mechanisms at the molecular level, which in turn allows further experimental MOF design for this application. MOFs with open metal sites, and particularly Fe-MOF-74, seem to be good for this separation, with a trade-off between physical adsorption capacity and selectivity. Based on experimental single-adsorption isotherms at various temperatures, we developed and validated a specific parameterization to account for the interactions of the olefin with the open metal sites. In addition to volumetric and calorimetric adsorption, we comprehensively investigate the characteristics of the interaction between the MOFs and the guest molecules in terms of binding sites and density profiles. The overall agreement of our simulated results with experimental data for pure components points to the reliability of the models and methods to successfully predict the separation of mixtures.
RESUMEN
This study investigated the effects of maternal separation on the feeding behavior of rats. A maternal separation model was used on postnatal day 1 (PND1), forming the following groups: in the maternal separation (MS) group, pups were separated from their mothers each day from PND1 to PND14, whereas in the control (C) group pups were kept with their mothers. Subgroups were formed to study the effects of light and darkness: control with dark and light exposure, female and male (CF and CM), and maternal separation with dark and light exposure, female and male (SDF, SDM, SLF and SLM). Female rats had higher caloric intake relative to body weight compared with male controls in the dark period only (CF=23.3±0.5 v. CM=18.2±0.7, P<0.001). Macronutrient feeding preferences were observed, with male rats exhibiting higher caloric intake from a protein diet as compared with female rats (CF=4.1±0.7, n=8 v. CM=7.0±0.5, n=8, P<0.05) and satiety development was not interrupted. Female rats had a higher adrenal weight as compared with male rats independently of experimental groups and exhibited a higher concentration of serum triglycerides (n=8, P<0.001). The study indicates possible phenotypic adjustments in the structure of feeding behavior promoted by maternal separation, especially in the dark cycle. The dissociation between the mother's presence and milk intake probably induces adjustments in feeding behavior during adulthood.
Asunto(s)
Preferencias Alimentarias/fisiología , Preferencias Alimentarias/psicología , Privación Materna , Saciedad/fisiología , Animales , Animales Recién Nacidos , Conducta Alimentaria/fisiología , Conducta Alimentaria/psicología , Femenino , Masculino , Embarazo , Ratas , Ratas WistarRESUMEN
Here we analyze the outcomes of unlimited access to a low-energy (LE) diet in dams and their offspring. At 3 weeks' gestation, pregnant Wistar rats were divided into two groups: (1) the control group received a normoenergetic diet; and (2) the experimental group received the LE diet. In dams, lactation outcomes, food intake, body weight, plasma IGF-1, prealbumin, transferrin and retinol-binding protein levels were evaluated; in offspring, biometric and biochemical parameters and food intake were evaluated. No differences were observed during pregnancy. However, after lactation, dams that received the LE diet demonstrated significant reductions in body weight (P<0.05), plasma IGF-1 (P=0.01), prealbumin and visceral fat (P<0.001). Pups born to dams that received the LE diet demonstrated reduced body length and weight at weaning (P<0.001) and were lighter than the control animals at the end of the experimental period. Pups also demonstrated reduced plasma, low-density lipoprotein (P=0.04), triglycerides (P=0.002) and glucose levels (P<0.05), and differences were noted in visceral fat. These results indicate that feeding dams with LE diet during the reproductive period induces acute malnutrition and impairs the growth and development of offspring, as well as certain metabolic parameters.
Asunto(s)
Fenómenos Fisiologicos de la Nutrición Prenatal , Animales , Peso Corporal , Ingestión de Alimentos , Metabolismo Energético , Femenino , Desarrollo Fetal , Desnutrición/etiología , Estado Nutricional , Valor Nutritivo , Embarazo , Ratas WistarRESUMEN
In early 2007, severe yellowing and chlorosis symptoms were observed in field-grown and greenhouse tomato (Solanum lycopersicum L.) plants in Costa Rica. Symptoms resembled those of the genus Crinivirus (family Closteroviridae), and large populations of whiteflies, including the greenhouse whitefly Trialeurodes vaporariorum (Westwood), were observed in the fields and on symptomatic plants. Total RNA was extracted from silica gel-dried tomato leaf tissue of 47 representative samples (all were from symptomatic plants) using TRI Reagent (Molecular Research Inc., Cincinnati, OH). Reverse transcription (RT)-PCR reactions were performed separately with each of the four primer sets with the Titan One-Tube RT-PCR Kit (Roche Diagnostics Corp., Chicago IL). Specific primers used for the detection of the criniviruses, Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV), were primer pair ToCV-p22-F (5'-ATGGATCTCACTGGTTGCTTGC-3') and ToCV-p22-R (5'-TTATATATCACTCCCAAAGAAA-3') specific for the p22 gene of ToCV RNA1 (1), primer pair ToCVCPmF (5'-TCTGGCAGTACCCGTTCGTGA-3') and ToCVCPmR (5'-TACCGGCAGTCGTCCCATACC-3') designed to be specific for the ToCV CPm gene of ToCV RNA2 (GenBank Accession No. AY903448) (2), primer pair ToCVHSP70F (5'-GGCGGTACTTTCGACACTTCTT-3') and ToCVHSP70R (5'-ATTAACGCGCAAAACCATCTG-3') designed to be specific for the Hsp70 gene of RNA2 of ToCV (GenBank Accession No. EU284744) (1), and primer pair TICV-CP-F and TICV-CP-R specific for the coat protein gene of TICV (1). Amplified DNA fragments (582 bp) were obtained from nine samples, four from the greenhouse and five from the open field, with the ToCV-p22 specific primers and were cloned into the pCRII TOPO cloning vector (Invitrogen, Carlsbad, CA). Nucleotide sequence analysis of all purified RT-PCR products verified their identity as ToCV, sharing 99.5 to 100% sequence identity among themselves and 96% to 98% sequence identity with previously reported ToCV p22 sequences from Florida (Accession No. AY903447), Spain (Accession No. DQ983480), and Greece (Accession No. EU284745). The presence of ToCV in the samples was confirmed by additional amplification and sequence analysis of the CPm (449-bp fragment) and Hsp70 (420-bp fragment) genes of ToCV RNA2 and sharing 98 to 99% sequence homology to Accession Nos. AY903448 and EU284774, respectively. One representative sequence of the p22 gene of the Costa Rican isolate was deposited at GenBank (Accession No. FJ809714). No PCR products were obtained using either the TICV-specific primers nor from healthy tomato tissue. The ToCV-positive samples were collected from a region in the Central Valley around Cartago, Costa Rica. To our knowledge, this is the first report of ToCV in Costa Rica. The economic impact on tomato has not yet been determined. Studies are underway to determine the incidence of ToCV in Costa Rica field-grown and greenhouse tomatoes. References: (1) A. R. A. Kataya et al. Plant Pathol. 57:819, 2008. (2) W. M. Wintermantel et al. Arch. Virol. 150:2287, 2005.
RESUMEN
A fish survey in 35 stream reaches (from 1st to 3rd order) with physicochemical and habitat assessment in the São José dos Dourados system, southeastern Brazil, was conducted. Most of the basin land cover (77.4%) is used for pasture. From the sampled stream reaches, 24 were of good physicochemical quality, 10 of fair quality, and only one of poor quality. A habitat assessment showed that 10 stream reaches were considered fair, 22 were poor, and 3 were very poor. Fifty species were collected and their abundances showed strong correlation with habitat descriptors. In addition to the correlation between fish abundance and habitat, some species also showed optimal distribution related to the degree of physical habitat conservation. Streams located in this region experience organic pollution, but the most important aspect is the decline of the instream physical habitat condition, especially in first order streams, which negatively affects coarse substrates and water column dependent fish species. Effluent control, riparian vegetation restoration programs, siltation control and adequate sustainable soil use are practices which could mitigate such impacts.
Asunto(s)
Ecosistema , Peces/clasificación , Ríos/química , Contaminación del Agua/análisis , Animales , Brasil , Fenómenos Químicos , Química Física , Densidad de Población , Estaciones del AñoRESUMEN
A ictiofauna de 35 trechos de riachos (de 1ª a 3ª ordem) no sistema do Rio São José dos Dourados, Sudeste do Brasil, foi estudada juntamente com a avaliação físico-química e física do hábitat. Na região estudada, 77,4% do solo é utilizado para pastagens. Quanto à avaliação físico-química da água, 24 trechos foram classificados como bons, 10 como regulares e um como pobre; quanto à avaliação física do hábitat, 10 foram considerados regulares, 22 como pobres e 3 como muito pobres. Cinqüenta espécies foram coletadas e suas abundâncias apresentaram forte correlação com descritores do hábitat. Em adição a esta correlação, observou-se que algumas espécies também demonstraram sua distribuição ótima coincidente com o grau de conservação do hábitat físico. Os riachos dessa região estão expostos a impactos provenientes de poluição orgânica, mas especialmente pequenos riachos de primeira ordem estão seriamente afetados pela perda de qualidade física do hábitat, que, negativamente, afeta tanto espécies de peixes dependentes de substratos rochosos como espécies que exploram a coluna d'água. Controle da entrada de efluentes, programas adequados de restauração da vegetação ripária, controle do aporte de sedimento e uso adequado e sustentável do solo são práticas que podem mitigar tais impactos.
Asunto(s)
Animales , Ecosistema , Peces/clasificación , Ríos/química , Contaminación del Agua/análisis , Brasil , Química Física , Densidad de Población , Estaciones del AñoRESUMEN
Studies in animals lacking the cellular prion protein (PrP(c)) gene (Prnp) showed higher neuronal excitability in vitro and increased sensitivity to seizures in vivo. The authors previously reported a rare polymorphism at codon 171 (Asn-->Ser) of human Prnp to be associated with mesial temporal lobe epilepsy related to hippocampal sclerosis. They demonstrated that the same variant allele is also associated with symptomatic epilepsies related to different forms of malformations of cortical development.
Asunto(s)
Sustitución de Aminoácidos , Amiloide/genética , Corteza Cerebral/anomalías , Epilepsia/genética , Polimorfismo de Nucleótido Simple , Precursores de Proteínas/genética , Adolescente , Adulto , Alelos , Apoptosis , Brasil/epidemiología , División Celular , Movimiento Celular , Corteza Cerebral/patología , Niño , Anomalías Congénitas/epidemiología , Anomalías Congénitas/genética , Anomalías Congénitas/patología , Análisis Mutacional de ADN , Epilepsia/epidemiología , Epilepsia/patología , Etnicidad/genética , Europa (Continente)/epidemiología , Femenino , Frecuencia de los Genes , Genotipo , Humanos , Masculino , Proteínas Priónicas , PrionesRESUMEN
BACKGROUND: Mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) is the most common surgically remediable epileptic syndrome. Ablation of the cellular prion protein (PrP(c)) gene (PRNP) enhances neuronal excitability of the hippocampus in vitro and sensitivity to seizure in vivo, indicating that PrP(c) might be related to epilepsy. OBJECTIVE: To evaluate the genetic contribution of PRNP to MTLE-HS. METHODS: The PRNP coding sequence of DNA from peripheral blood cells of 100 consecutive patients with surgically treated MTLE-HS was compared to that from a group of healthy controls adjusted for sex, age, and ethnicity (n = 180). The presence of PRNP variant alleles was correlated with clinical and presurgical parameters as well as surgical outcome. RESULTS: A variant allele at position 171 (Asn-->Ser), absent in controls, was found in heterozygosis (Asn171Ser) in 23% of patients (p < 0.0001). The PRNP genotypes were not correlated with any clinical or presurgical data investigated. However, patients carrying the Asn171Ser variant had a five times higher chance of continuing to have seizures after temporal lobectomy (95% CI 1.65 to 17.33, p = 0.005) than those carrying the normal allele. At 18 months after surgery, 91.8% of patients with the normal allele at codon 171 were seizure free, in comparison to 68.2% of those carrying Asn171Ser (p = 0.005). CONCLUSIONS: The PRNP variant allele Asn171Ser is highly prevalent in patients with medically untreatable MTLE-HS and influences their surgical outcome. The results suggest that the PRNP variant allele at codon 171 (Asn171Ser) is associated with epileptogenesis in MTLE-HS.
Asunto(s)
Epilepsia del Lóbulo Temporal/fisiopatología , Epilepsia del Lóbulo Temporal/cirugía , Variación Genética/genética , Priones/genética , Esclerosis/genética , Adulto , Sustitución de Aminoácidos , Química Encefálica , ADN/análisis , Supervivencia sin Enfermedad , Epilepsia del Lóbulo Temporal/complicaciones , Etnicidad/estadística & datos numéricos , Femenino , Frecuencia de los Genes , Hipocampo/patología , Humanos , Imagen por Resonancia Magnética , Masculino , Oportunidad Relativa , Esclerosis/complicaciones , Esclerosis/patología , Distribución por Sexo , Resultado del TratamientoRESUMEN
OBJECTIVE: To assess the effectiveness of the combination of colchicine and vitamin E (which has anti-fibrotic, anti-mitotic and anti-inflammatory effects) in modifying the early stages of Peyronie's disease, by evaluating pain relief, correction of deformities and plaque size. PATIENTS AND METHODS: In all, 45 patients were divided into two groups and treated from January 1998 to November 2001. Their mean (range) age was 53.4 (40-62) years, the time from onset of the disease < 6 months and they had penile deformity of < 30 degrees; no patient had erectile dysfunction. Twenty-two patients were given ibuprofen 400 mg/day for 6 months, whilst 23 received a combination of vitamin E 600 mg/day plus colchicine 1 mg every 12 h. Pain, plaque size and penile deformity were assessed at 6 months. RESULTS: There were no statistically significant differences between the groups at baseline in age, time from onset of the disease until the initial evaluation or plaque size. Although the proportion of patients reporting pain relief was higher amongst those receiving colchicine plus vitamin E (91% vs 68%) this was not significantly different, but differences in plaque size and penile curvature were significant. CONCLUSIONS: The use of colchicine plus vitamin E during the early stages of Peyronie's disease (time from onset < 6 months) in patients with penile curvature of < 30 degrees and no erectile dysfunction is an effective and well-tolerated way to stabilize the disease. A more extensive study is needed, comparing these results with other oral therapies.
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Antiinflamatorios/uso terapéutico , Antioxidantes/uso terapéutico , Colchicina/uso terapéutico , Induración Peniana/tratamiento farmacológico , Vitamina E/uso terapéutico , Adulto , Edad de Inicio , Antiinflamatorios no Esteroideos/uso terapéutico , Quimioterapia Combinada , Humanos , Masculino , Persona de Mediana Edad , Dolor/etiología , Dolor/prevención & control , Erección Peniana , Método Simple CiegoRESUMEN
Despite the essential role played by myelin basic protein (MBP) in stabilizing the multilamellar structure of the myelin membrane, attempts at deciphering the structure of MPB have so far failed. Given that MBP is known to specifically interact with the membrane's lipid components, this study was designed to explore the effects of these lipids on the conformation of the protein by examining its interaction with the lipid triphosphoinositide (TPI). MBP was identified by high-performance liquid chromatography (HPLC) in myelin extracted from cow's brain and its molecular weight determined. In aqueous solution, MBP showed a random coil structure confirmed by its circular dichroism (CD) spectra. Possible structural changes to the protein induced by different proportions of TPI were also explored. The CD spectra of these mixtures indicated that this lipid fails to induce the adoption of a secondary structure by MBP. We then performed monolayer experiments to evaluate the type of interaction that occurs between MBP and TPI. First, the molecular weight of the protein sample was established to determine the state of the MBP within the monolayer by applying the equation for gases to the so-called gaseous zone of the monolayer for the conditions under which the expression holds. The similar molecular weights yielded by HPLC performed on dissolved samples and by the monolayers suggests that, as in solution, in the membrane the protein exists as a monomer. Monolayer data suggest forces of attraction between the two components and, through thermodynamic calculations, it was established that this interaction is spontaneous and the interaction is of the electrostatic type.
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Proteína Básica de Mielina/química , Fosfatos de Fosfatidilinositol/química , Animales , Calibración , Bovinos , Cromatografía Líquida de Alta Presión , Dicroismo Circular , Proteína Básica de Mielina/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Presión , Temperatura , Termodinámica , Factores de TiempoRESUMEN
The effect of the malnutrition during suckling on the aggressiveness was investigated in adult rats treated or not with citalopram, a selective serotonin reuptake inhibitor (SSRI). The animals were divided into two groups according to the diet used: nourished group - the rats received the control diet with 23% protein during the life; and malnourished group - the rats had its mothers submitted to diet with 7.8% protein during suckling. At 120 days of age, each group was sub-divided according to the treatment: acute - consisting a single i.p. injection of saline solution or 20-mg/Kg citalopram; chronic - consisting the single injections (1 per day during 14 days) of saline or 20 mg/Kg citalopram. The acute or chronic treatment with SSRI reduces aggressive response in nourished rats, but not in malnourished ones. Thus, the malnutrition during the critical period of brain development seems to induce durable alterations in the function of the serotoninergic neurotransmission
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Agresión/efectos de los fármacos , Conducta Animal/efectos de los fármacos , Citalopram/farmacología , Trastornos Nutricionales/complicaciones , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Animales , Animales Lactantes , Peso Corporal , Encéfalo/crecimiento & desarrollo , Dieta , Femenino , Lactancia , Masculino , Trastornos Nutricionales/metabolismo , Ratas , Ratas WistarRESUMEN
OBJECTIVE: To assess the safety and efficacy of sildenafil citrate in renal transplant patients with erectile dysfunction, as up to half of men with renal failure may be affected and only 60-75% recover potency after transplantation. PATIENTS AND METHODS: Fifty patients with erectile dysfunction and a functioning renal transplant were treated using sildenafil (mean age 54 years, mean time on dialysis 35 months, mean time from transplantation 20 months). The hypogastric artery was not used during transplantation in any patient. Sildenafil citrate was prescribed at doses of 25 or 50 mg depending on baseline creatinine values and on the response, and plasma levels of cyclosporin/FK506 were monitored. RESULTS: Thirty patients (60%) had a satisfactory response, with a mean time on dialysis of 23 months. Six patients (12%) did not take the sildenafil and in 14 (28%) the drug was ineffective. The mean time on dialysis in this group was 43 months. Six patients (12%) had side-effects that in no case led to withdrawal of treatment. Plasma levels of cyclosporin/FK506 remained within the safety and efficacy limits in all patients. CONCLUSIONS: Treatment with sildenafil citrate in renal transplant patients with erectile dysfunction is an effective and safe option, with few side-effects. Plasma levels of immunosuppressants are unchanged. The response was more effective in patients with a shorter time on dialysis, as penile vascular disease is less advanced.
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Disfunción Eréctil/tratamiento farmacológico , Trasplante de Riñón/efectos adversos , Inhibidores de Fosfodiesterasa/administración & dosificación , Piperazinas/administración & dosificación , Humanos , Masculino , Persona de Mediana Edad , Satisfacción del Paciente , Cuidados Posoperatorios/métodos , Purinas , Citrato de Sildenafil , Sulfonas , Resultado del TratamientoRESUMEN
Prions have been extensively studied since they represent a new class of infectious agents in which a protein, PrPsc (prion scrapie), appears to be the sole component of the infectious particle. They are responsible for transmissible spongiform encephalopathies, which affect both humans and animals. The mechanism of disease propagation is well understood and involves the interaction of PrPsc with its cellular isoform (PrPc) and subsequently abnormal structural conversion of the latter. PrPc is a glycoprotein anchored on the cell surface by a glycosylphosphatidylinositol moiety and expressed in most cell types but mainly in neurons. Prion diseases have been associated with the accumulation of the abnormally folded protein and its neurotoxic effects; however, it is not known if PrPc loss of function is an important component. New efforts are addressing this question and trying to characterize the physiological function of PrPc. At least four different mouse strains in which the PrP gene was ablated were generated and the results regarding their phenotype are controversial. Localization of PrPc on the cell membrane makes it a potential candidate for a ligand uptake, cell adhesion and recognition molecule or a membrane signaling molecule. Recent data have shown a potential role for PrPc in the metabolism of copper and moreover that this metal stimulates PrPc endocytosis. Our group has recently demonstrated that PrPc is a high affinity laminin ligand and that this interaction mediates neuronal cell adhesion and neurite extension and maintenance. Moreover, PrPc-caveolin-1 dependent coupling seems to trigger the tyrosine kinase Fyn activation. These data provide the first evidence for PrPc involvement in signal transduction
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Humanos , Animales , Ratones , Proteínas de la Membrana/fisiología , Enfermedades por Prión/fisiopatología , Proteínas PrPC/fisiología , Cobre/metabolismo , Endocitosis , Laminina/fisiología , Ligandos , Proteínas de la Membrana/genética , Fenotipo , Proteínas PrPC/genética , Proteínas PrPC/aislamiento & purificación , Proteínas PrPSc/genéticaRESUMEN
Prions have been extensively studied since they represent a new class of infectious agents in which a protein, PrPsc (prion scrapie), appears to be the sole component of the infectious particle. They are responsible for transmissible spongiform encephalopathies, which affect both humans and animals. The mechanism of disease propagation is well understood and involves the interaction of PrPsc with its cellular isoform (PrPc) and subsequently abnormal structural conversion of the latter. PrPc is a glycoprotein anchored on the cell surface by a glycosylphosphatidylinositol moiety and expressed in most cell types but mainly in neurons. Prion diseases have been associated with the accumulation of the abnormally folded protein and its neurotoxic effects; however, it is not known if PrPc loss of function is an important component. New efforts are addressing this question and trying to characterize the physiological function of PrPc. At least four different mouse strains in which the PrP gene was ablated were generated and the results regarding their phenotype are controversial. Localization of PrPc on the cell membrane makes it a potential candidate for a ligand uptake, cell adhesion and recognition molecule or a membrane signaling molecule. Recent data have shown a potential role for PrPc in the metabolism of copper and moreover that this metal stimulates PrPc endocytosis. Our group has recently demonstrated that PrPc is a high affinity laminin ligand and that this interaction mediates neuronal cell adhesion and neurite extension and maintenance. Moreover, PrPc-caveolin-1 dependent coupling seems to trigger the tyrosine kinase Fyn activation. These data provide the first evidence for PrPc involvement in signal transduction.
Asunto(s)
Proteínas de la Membrana/fisiología , Proteínas PrPC/fisiología , Enfermedades por Prión/fisiopatología , Animales , Cobre/metabolismo , Endocitosis , Humanos , Laminina/fisiología , Ligandos , Proteínas de la Membrana/genética , Ratones , Fenotipo , Proteínas PrPC/genética , Proteínas PrPC/aislamiento & purificación , Proteínas PrPSc/genética , Transducción de SeñalRESUMEN
Objetivos. Los sarcomas primarios de mama son procesos patológicos poco frecuentes (< 1 por ciento). Después de tratar 3 casos en nuestro servicio, revisamos la casuística nacional con el objetivo de conocer mejor su comportamiento clínico y el tratamiento más adecuado. Material y métodos. Revisamos 11 casos de sarcoma primario de mama, publicados desde 1988 hasta el momento actual. Todas las pacientes fueron mujeres, de edades comprendidas entre 40 y 81 años (media 56,8). Estudiamos factores pronósticos como el tipo y el grado histológico, el tamaño del tumor y el tratamiento efectuado, para relacionarlos con su evolución y supervivencia. Resultados. Los tipos histológicos hallados corresponden a 4 liposarcomas, 2 angiosarcomas, 2 histiocitomas fibrosos malignos, un leiomiosarcoma, un osteosarcoma y un sarcoma estromal. El tamaño tumoral máximo osciló entre 13 y 1,5 cm (media, 5,5). Sólo en un caso se describió un bajo grado histológico. En 9 casos a la mastectomía se asoció una linfadenectomía y en cuatro se asoció radioterapia postoperatoria. Las 2 pacientes que fallecieron lo hicieron por diseminación metastásica. Conclusiones. El factor pronóstico que más se relaciona con la incidencia de metástasis y la mortalidad es el tipo histológico (angiosarcoma y osteosarcoma); el tamaño tumoral y el grado histológico son factores coadyuvantes menos importantes y sin repercusión en las recidivas y la supervivencia. El tratamiento quirúrgico está sobrevalorado, con un 81,8 por ciento de linfadenectomías innecesarias (AU)
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Adulto , Femenino , Persona de Mediana Edad , Humanos , Neoplasias de la MamaRESUMEN
The objective of this work is to study the interaction of a copolymer, poly methyl vinyl ether/maleic anhydride (PMV/MA) used in pharmaceutical dosage form and a phospholipid L-alpha-dimiristoyl phosphatidylcholine (DMPC) with the aim of developing a bioadhesive system. Glycerine is the plastifiant used to make PMV/MA insoluble. We have studied copolymer-plastifiant compatibility with differential scanning calorimetry and we have studied the influence that the solvents produce on the copolymer by infrared spectroscopy. Monolayer experiments were carried out with a Wilhelmy-type surface balance. The purpose of these experiments is to obtain molecular information about interaction PMV/MA-glycerine system with DMPC. The results show that there are attractive forces and it is a spontaneous process.
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Dimiristoilfosfatidilcolina/química , Maleatos/química , Fosfatidilcolinas/química , Poliésteres/química , Polietilenos/química , Acetona , Rastreo Diferencial de Calorimetría , Preparaciones de Acción Retardada , Dioxanos , Glicerol/química , Vehículos Farmacéuticos , Solventes , Espectrofotometría InfrarrojaRESUMEN
Asthma is the most common chronic disease among children and adolescents, and in recent decades dramatic increases in its prevalence have been reported around the world. However, previous studies have been based on a variety of methodological approaches, making it difficult to compare the results. That situation led a group of international researchers to prepare a standardized self-administered questionnaire to carry out cooperative international studies for the International Study of Asthma and Allergies in Childhood (ISAAC). During April 1996 a cross-sectional study using the ISAAC questionnaire was performed in the city of Campos Gerais, Minas Gerais, Brazil, to determine the prevalence of wheezing and other signs and symptoms related to bronchial asthma among schoolchildren. Two medical students interviewed a randomly selected sample of 200 adolescents 13-14 years old registered in public schools in the city. The sample was equally distributed by sex and age. Of the schoolchildren, 28.5% (95% CI: 22.3%-35.3%) had had wheezing or whistling in the chest at some point in the past. In the preceding 12 months, 6% of them (95% CI: 3.1%-10.5%) had had at least one wheezing episode. A comparison of these results with ones from larger Brazilian cities studied showed that higher prevalence rates were associated with higher population densities and greater urbanization and industrialization. These results strengthen theories supporting an association between asthma and environmental factors. From this it follows that it is necessary to deal with asthma as an important public health problem in Brazil.