Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
1.
PeerJ ; 11: e14840, 2023.
Article in English | MEDLINE | ID: mdl-36788808

ABSTRACT

The snail Pomacea flagellata inhabits aquatic systems with high calcium concentration and it is important to food webs; unfortunately, its natural populations are decreasing due to overfishing and habitat destruction. Here we tested the effect of three water calcium concentrations on the growth and hardness of snail shells in triplicate recirculation culture systems for 12 weeks. In each culture, 100 juvenile snails were seeded at constant density and fed with balanced tilapia feed. Thirty snails were randomly collected every 15 days and measured in length and total weight. The size, weight, and shell hardness of the snails for the 500 mg/L calcium treatment were significantly higher than the mean size of the snails in the other treatments (300 mg/L and 243.33 mg/L). The calcium supply in the culture promotes growth and allows the snails to produce healthier and stronger shells, in addition to improving their growth rate, which is important for the management of the species.


Subject(s)
Conservation of Natural Resources , Fisheries , Hardness , Water , Ecosystem , Calcium, Dietary
2.
Article in English | MEDLINE | ID: mdl-35162836

ABSTRACT

Self-perceived emotional intelligence in healthcare personnel is not just an individual skill but a work tool, which is even more necessary in times of crisis. This article aimed to determine emotional intelligence as perceived by students studying nursing at the University of Colima, Mexico, a year after the start of the COVID-19 pandemic. A cross-sectional survey of an academic year stratified population of 349 students was conducted, using the Trait Meta-Mood Scale-24 instrument. A global descriptive analysis was performed for each school year. Additionally, an ANOVA was performed, and a Multiple Correspondence Analysis was executed. It is essential to highlight the high percentages for emotional attention within the results. However, a large percentage of students required improvement in emotional attention, clarity, and repair. According to their school year, significant differences were observed among student groups within the three emotional intelligence subscales (p < 0.05). Second-year students had low levels in the three subscales of emotional intelligence, while fourth-year students had adequate levels. We established that the scores were different depending on the school year, with a significant decrease in second-year students. The implementation of educational programs could aid in the development of emotional skills in students from the health field, especially in times of crisis.


Subject(s)
COVID-19 , Students, Nursing , Cross-Sectional Studies , Emotional Intelligence , Humans , Pandemics , SARS-CoV-2
3.
Rev Alerg Mex ; 66(3): 308-313, 2019.
Article in Spanish | MEDLINE | ID: mdl-31606014

ABSTRACT

BACKGROUND: The diagnosis of asthma is confirmed with a spirometry: FEV1 ratio (forced expiratory volume in one second)/FVC (forced vital capacity) <80% with reversibility (FEV1 >12% or 200 mL) after using salbutamol. The peak expiratory flow is cheap and easy to use; it measures the forced expiratory flow, of which reversibility > 20% suggests asthma. OBJECTIVE: To know the sensitivity, specificity, and the positive and negative predictive values of the flowmeter. METHODS: A cross-sectional, observational, comparative study. Individuals aged >18 years without contraindications for spirometry were included. They underwent spirometry and peak expiratory flow, and the ACT (Asthma Control Test) questionnaire was applied to them. Sensitivity, specificity, positive predictive value and negative predictive value of the flowmetry were calculated. ROC curve was carried out in order to know the cut-off point of greater sensitivity and specificity. RESULTS: Of 150 patients, 66% were male; the median age was 38 years. According to the guidelines of GINA 2018 (Global Initiative for Asthma); 58.7% were controlled. The sensitivity of the peak expiratory flow was 47%, and the specificity was 87%, with a positive predictive value of 54.8% and a negative predictive value of 84%. The peak expiratory flow showed higher specificity with FEV1 <59%. The cut-off point of greater sensitivity and specificity was a reversibility of 8%, with an area under the curve of 0.70. CONCLUSIONS: The flowmeter has got greater sensitivity in airway obstructions; it is useful when a spirometer is not available.


Antecedentes: El diagnóstico de asma se confirma con espirometría: VEF1 (volumen espiratorio forzado del primer segundo)/CVF (capacidad vital forzada) < 80 %, con reversibilidad (VEF1 >12 % o 200 mL) tras utilizar salbutamol. El flujómetro es barato y fácil de utilizar, mide el flujo espiratorio forzado, cuya reversibilidad > 20 % sugiere asma. Objetivo: Conocer sensibilidad, especificidad y valores predictivos positivos y negativo del flujómetro. Métodos: Estudio transversal, observacional, comparativo. Se incluyó a individuos > 18 años sin contraindicaciones para espirometría, quienes fueron sometidos a espirometría y flujometría y se les aplicó el Asthma Control Test. Se calculó sensibilidad, especificidad y valores predictivos positivo y negativo de la flujometría. Se realizó curva ROC para conocer el punto de corte de mayor sensibilidad y especificidad. Resultados: De 150 pacientes, 66 % fue del sexo masculino; la mediana de edad fue de 38 años. Conforme los criterios de Global Initiative for Asthma 2018, 58.7 % estaba controlado. La sensibilidad de la flujometría fue de 47 %, la especificidad de 87 %, valor predictivo positivo de 54.8 % y negativo de 84 %. La flujometría mostró mayor especificidad con VEF1 < 59 %. El punto de corte de mayor sensibilidad y especificidad fue una reversibilidad de 8 %, con área bajo la curva de 0.70. Conclusiones: El flujómetro tiene mayor sensibilidad en obstrucciones de vía aérea; es de utilidad cuando no se cuenta con un espirómetro.


Subject(s)
Asthma/diagnosis , Asthma/physiopathology , Peak Expiratory Flow Rate , Spirometry , Adult , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Sensitivity and Specificity
4.
J Food Prot ; 81(11): 1748-1754, 2018 11.
Article in English | MEDLINE | ID: mdl-30272999

ABSTRACT

Cheesemaking is one of the most important industries in Mexico. Among all the Mexican cheeses, fresh cheeses are the most popular and most consumed cheese in Mexico and Latin America. However, in Mexico fresh cheese is frequently made with unpasteurized milk and sold in public markets. This may increase the risk for contamination of dairy products with pathogenic bacteria. The presence of multidrug-resistant pathogenic bacteria in food is an important public health concern. Diarrheagenic Escherichia coli pathotypes (DEPs) are foodborne bacteria. This study investigated the presence of indicator bacteria and multidrug-resistant DEPs in fresh cheeses. A total of 120 fresh cheese samples were collected from public markets in the city of Pachuca, Mexico. The samples were analyzed for presence of fecal coliforms (FC), E. coli, and antibiotic resistant DEPs. FC and E. coli were analyzed using the most-probable-number technique. DEPs were identified using two multiplex PCR methods. Susceptibility to 16 antibiotics was tested for the isolated DEPs strains by the standard assay. The frequency of FC, E. coli, and DEPs in the cheese samples was 50, 40, and 19%, respectively. The identified DEPs included Shiga toxin-producing E. coli (STEC; 8%), enteropathogenic E. coli (EPEC; 6%), and enterotoxigenic E. coli (ETEC; 5%). All isolated strains exhibited resistance to at least five antibiotics. One, one, two, and three STEC strains were resistant to 14, 12, 11, and 10 antibiotics, respectively. One strain of EPEC was resistant to 11 antibiotics, three EPEC strains to 9, and one strain to 7. One, one, and two strains of ETEC were resistant to 10, 8, and 7 antibiotics, respectively. The results of the present study indicate that fresh cheeses made with unpasteurized milk could be a risk for consumers, both for native people and visitors to Mexico.


Subject(s)
Cheese , Drug Resistance, Multiple, Bacterial , Enteropathogenic Escherichia coli , Enterotoxigenic Escherichia coli , Food Contamination/analysis , Shiga-Toxigenic Escherichia coli , Cheese/microbiology , Enteropathogenic Escherichia coli/drug effects , Enteropathogenic Escherichia coli/isolation & purification , Enterotoxigenic Escherichia coli/drug effects , Enterotoxigenic Escherichia coli/isolation & purification , Mexico , Shiga-Toxigenic Escherichia coli/drug effects , Shiga-Toxigenic Escherichia coli/isolation & purification
5.
Korean J Physiol Pharmacol ; 21(4): 407-413, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28706454

ABSTRACT

Vascular reactivity can be influenced by the vascular region, animal age, and pathologies present. Prostaglandins (produced by COX-1 and COX-2) play an important role in the contractile response to phenylephrine in the abdominal aorta of young rats. Although these COXs are found in many tissues, their distribution and role in vascular reactivity are not clear. At a vascular level, they take part in the homeostasis functions involved in many physiological and pathologic processes (e.g., arterial pressure and inflammatory processes). The aim of this study was to analyze changes in the contractile response to phenylephrine of thoracic/abdominal aorta and the coronary artery during aging in rats. Three groups of rats were formed and sacrificed at three distinct ages: prepubescent, young and old adult. The results suggest that there is a higher participation of prostanoids in the contractile effect of phenylephrine in pre-pubescent rats, and a lower participation of the same in old rats. Contrarily, there seems to be a higher participation of prostanoids in the contractile response of the coronary artery of older than pre-pubescent rats. Considering that the changes in the expression of COX-2 were similar for the three age groups and the two tissues tested, and that expression of COX-1 is apparently greater in older rats, COX-1 and COX-2 may lose functionality in relation to their corresponding receptors during aging in rats.

6.
Oxid Med Cell Longev ; 2016: 3850402, 2016.
Article in English | MEDLINE | ID: mdl-27990229

ABSTRACT

This work was performed to study the effect of allicin on hypertension and cardiac function in a rat model of CKD. The groups were control, CKD (5/6 nephrectomy), and CKD-allicin treated (CKDA) (40 mg/kg day/p.o.). Blood pressure was monitored (weekly/6 weeks). The cardiac function, vascular response to angiotensin II, oxidative stress, and heart morphometric parameters were determined. The CKD group showed hypertension and proteinuria. The coronary perfusion and left ventricular pressures were decreased in CKD group. In contrast, the vascular response to angiotensin II and expression of angiotensin II type 1 receptor (AT1R) were increased. These data were associated with the increment in morphometric parameters (weight of heart and left ventricle, heart/BW and left ventricular mass index, and wall thickness). Concurrently, the oxidative stress was increased and correlated inversely with the expression of Nrf2, Keap1, and antioxidant enzymes Nrf2-regulated. Allicin treatment attenuated hypertension and improved the renal and the cardiac dysfunctions; furthermore, it decreased the vascular reactivity to angiotensin II, AT1R overexpression, and preserved morphometric parameters. Allicin also downregulated Keap1 and increased Nrf2 expression, upregulated the antioxidant enzymes, and reduced oxidative stress. In conclusion, allicin showed an antihypertensive, nephroprotective, cardioprotective, and antioxidant effects, likely through downregulation of AT1R and Keap1 expression.


Subject(s)
Hypertension/drug therapy , Hypertension/physiopathology , Renal Insufficiency, Chronic/drug therapy , Renal Insufficiency, Chronic/physiopathology , Sulfinic Acids/therapeutic use , Animals , Antioxidants/metabolism , Blood Pressure/drug effects , Body Weight/drug effects , Disulfides , Heart Function Tests , Heart Ventricles/drug effects , Heart Ventricles/pathology , Heart Ventricles/physiopathology , Hypertension/complications , Hypertension/metabolism , Kidney/drug effects , Kidney/physiopathology , Kidney Function Tests , Male , Myocardium/enzymology , Myocardium/pathology , NF-E2-Related Factor 2/metabolism , Oxidative Stress/drug effects , Perfusion , Rats, Wistar , Receptor, Angiotensin, Type 1/metabolism , Renal Insufficiency, Chronic/complications , Renal Insufficiency, Chronic/metabolism , Sulfinic Acids/pharmacology , Systole/drug effects
7.
Arch. méd. Camaguey ; 18(2)feb.-abr. 2014.
Article in Spanish | CUMED | ID: cum-59446

ABSTRACT

Fundamento: la warfarina es el anticoagulante oral más usado en todo el mundo para la profilaxis de las complicaciones tromboembólicas que acompañan a diversas enfermedades cardiovasculares; la resistencia a este fármaco se convierte en un verdadero problema de salud para los pacientes que lo necesitan.Objetivo: revisar las diferentes causas que pueden influir en una mayor resistencia y sensibilidad a la warfarina. Método: se realizó una búsqueda bibliográfica en Scopus a través de HInari, en la BVS, en Scielo y en Medline a través de PubMed. Se utilizaron los siguientes descriptores: warfarina, anticoagulante, resistencia y sensibilidad, contraindicaciones. Se obtuvo un total de 234 referencias, de ellas, 94 fueron seleccionadas para este estudio. Según el tipo de referencia, incluían ocho revisiones sistemáticas, cuatro ensayos clínicos controlados además de estudios observacionales y presentaciones de casos clínicos, se creó una lista bibliográfica que permitió la acotación de las referencias.Desarrollo: actualmente la warfarina es el anticoagulante oral prescrito mayoritariamente para la prevención y el tratamiento de desórdenes tromboembólicos, pese a estar entre los medicamentos asociados con alta incidencia de efectos indeseables; su reacción adversa más común y peligrosa es el sangrado, que puede llegar a ser fatal y se agrega la gran variabilidad interindividual en la respuesta al tratamiento, así como sus numerosas interacciones farmacológicas, factores que se conjugan para hacer de la warfarina un medicamento difícil de manejar. Conclusiones: la alta variabilidad de los factores que pueden interferir con la warfarina, hace de este fármaco uno de los más difíciles en su manejo; la dieta, la asociación con otros fármacos y la base genética de los pacientes son los factores que mayormente intervienen en la resistencia y sensibilidad a este fármaco(AU)


Background: warfarin is the most used oral anticoagulant in the world for treating the tromboembolic complications of prophylaxis that come with several cardiovascular diseases. Resistance to this medicine becomes a real health problem for those patients who need it.Objective: to revise the different causes that can have an influence on a greater resistance and sensibility to warfarin.Method: a bibliographic review in Scopus through HInari and in the BVS, in Scielo and in Medline through PubMed, was made. The following descriptors were used: warfarin, anticoagulant, resistance and sensibility, and contraindications. A total of 234 references were obtained; 94 of them were selected for this study. According to the type of reference, they included eight systematic reviews, four controlled clinical trials, and some observational studies and clinical case presentations. A bibliographical list that permitted the annotation of references was created.Development: nowadays, warfarin is the anticoagulant mainly prescribed for the prevention and treatment of tromboembolic disorders in spite of being among the medicaments associate to a high incidence of undesirable effects. The most common and dangerous adverse reaction of warfarin is bleeding which may even be fatal; to this is added the interindividual variability in the response to the treatment; as well as its many pharmacological interactions. All these factors together can make of warfarin a difficult medicine to handle.Conclusions: the high variability of these factors that may interfere with warfarin, make of this medicament one of the most difficult ones to handle. Diet, association with other medicine and the genetic base of the patients are the factors that can mainly intervene in the resistance and sensibility to this medicament(AU)


Subject(s)
Humans , Warfarin/therapeutic use , Anticoagulants/adverse effects , Anticoagulants/therapeutic use , Anticoagulants , Thromboembolism
8.
Arch. méd. Camaguey ; 18(2): 226-239, feb.-abr. 2014.
Article in Spanish | LILACS | ID: lil-715484

ABSTRACT

Fundamento: la warfarina es el anticoagulante oral más usado en todo el mundo para la profilaxis de las complicaciones tromboembólicas que acompañan a diversas enfermedades cardiovasculares; la resistencia a este fármaco se convierte en un verdadero problema de salud para los pacientes que lo necesitan. Objetivo: revisar las diferentes causas que pueden influir en una mayor resistencia y sensibilidad a la warfarina. Método: se realizó una búsqueda bibliográfica en Scopus a través de HInari, en la BVS, en Scielo y en Medline a través de PubMed. Se utilizaron los siguientes descriptores: warfarina, anticoagulante, resistencia y sensibilidad, contraindicaciones. Se obtuvo un total de 234 referencias, de ellas, 94 fueron seleccionadas para este estudio. Según el tipo de referencia, incluían ocho revisiones sistemáticas, cuatro ensayos clínicos controlados además de estudios observacionales y presentaciones de casos clínicos, se creó una lista bibliográfica que permitió la acotación de las referencias. Desarrollo: actualmente la warfarina es el anticoagulante oral prescrito mayoritariamente para la prevención y el tratamiento de desórdenes tromboembólicos, pese a estar entre los medicamentos asociados con alta incidencia de efectos indeseables; su reacción adversa más común y peligrosa es el sangrado, que puede llegar a ser fatal y se agrega la gran variabilidad interindividual en la respuesta al tratamiento, así como sus numerosas interacciones farmacológicas, factores que se conjugan para hacer de la warfarina un medicamento difícil de manejar. Conclusiones: la alta variabilidad de los factores que pueden interferir con la warfarina, hace de este fármaco uno de los más difíciles en su manejo; la dieta, la asociación con otros fármacos y la base genética de los pacientes son los factores que mayormente intervienen en la resistencia y sensibilidad a este fármaco.


Background: warfarin is the most used oral anticoagulant in the world for treating the tromboembolic complications of prophylaxis that come with several cardiovascular diseases. Resistance to this medicine becomes a real health problem for those patients who need it. Objective: to revise the different causes that can have an influence on a greater resistance and sensibility to warfarin. Method: a bibliographic review in Scopus through HInari and in the BVS, in Scielo and in Medline through PubMed, was made. The following descriptors were used: warfarin, anticoagulant, resistance and sensibility, and contraindications. A total of 234 references were obtained; 94 of them were selected for this study. According to the type of reference, they included eight systematic reviews, four controlled clinical trials, and some observational studies and clinical case presentations. A bibliographical list that permitted the annotation of references was created. Development: nowadays, warfarin is the main oral anticoagulant prescribed for the prevention and treatment of tromboembolic disorders in spite of being among the medicaments associate to a high incidence of undesirable effects. The most common and dangerous adverse reaction of warfarin is bleeding which may even be fatal; to this is added the interindividual variability in the response to the treatment; as well as its many pharmacological interactions. All these factors together can make of warfarin a difficult medicine to handle. Conclusions: the high variability of these factors that may interfere with warfarin, make of this medicament one of the most difficult ones to handle. Diet, association with other medicine and the genetic base of the patients are the factors that can mainly intervene in the resistance and sensibility to this medicament.

10.
MEDICC Rev ; 14(2): 23-9, 2012 04.
Article in English | MEDLINE | ID: mdl-22580550

ABSTRACT

INTRODUCTION: Studies of neuroplasticity have shown that the brain's neural networks change in the absence of sensory input such as hearing or vision. However, little is known about what happens when both sensory modalities are lost (deaf-blindness). Hence, this study of cortical reorganization in visually-impaired child cochlear implant (CI) candidates. OBJECTIVE: Assess cross-modal plasticity, specifically cortical reorganization for tactile representation in visually-impaired child CI candidates, through study of topography of somatosensory evoked potentials (SEP). METHODS: From April through September 2005, SEP from median and tibial nerve electrical stimulation were studied in 12 visually-impaired child CI candidates aged 3-15 years and 23 healthy controls. Following placement of 19 recording electrodes using the International 10-20 System , SEP were recorded and then processed. Topographic maps were obtained for SEP N20 (median nerve) and SEP P40 (tibial nerve), permitting assessment of cortical reorganization by comparing visually-impaired, deaf children's maps with those of healthy children by means of visual inspection and statistical comparison using a permutation test. RESULTS: SEP N20 topography was significantly more extensive in visually-impaired child CI candidates than in healthy children. An asymmetrical pattern occurred from the expansion of hand tactile activation into the temporal and occipital regions in the left hemisphere on right median nerve stimulation. This did not occur for SEP P40 on tibial nerve stimulation (right and left). Magnitude of expanded SEP N20 response was related to severity of visual impairment and longer duration of dual sensory loss. CONCLUSIONS: Changes in SEP N20 topography are evidence of cross-modal plasticity in visually-impaired child CI candidates, appearing to result from a complex interaction between severity of visual impairment and duration of multisensory deprivation.


Subject(s)
Cochlear Implants , Deaf-Blind Disorders/physiopathology , Evoked Potentials, Somatosensory/physiology , Neuronal Plasticity/physiology , Adolescent , Case-Control Studies , Child , Child, Preschool , Cochlear Implants/psychology , Cuba , Deaf-Blind Disorders/rehabilitation , Female , Humans , Male , Prospective Studies , Tibial Nerve/physiopathology
11.
J Insect Sci ; 12: 142, 2012.
Article in English | MEDLINE | ID: mdl-23461766

ABSTRACT

Descriptions of the immature stages of Taosa (Cuernavaca) longula Remes Lenicov (Hemiptera: Fulgoroidea: Dictyopharidae) and a key for their identification is provided for specimens collected on the water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Commelinales: Pontederiaceae), in northeastern Argentina and Peru. Newly emerged nymphs from eggs collected in the field were reared in rearing chambers, and each stage was fixed to microscopic examination and illustration. Fifth nymphal instars can be easily recognized from congeners by the brown marked pattern coloration, shorter vertex, and the distinguishable median carina along the frons. Information on behavior and developmental time is also included.


Subject(s)
Hemiptera/anatomy & histology , Animals , Argentina , Hemiptera/classification , Hemiptera/growth & development , Hemiptera/physiology , Nymph/anatomy & histology , Nymph/classification , Nymph/growth & development , Nymph/physiology , Ovum/growth & development , Ovum/physiology , Peru , Pigmentation
12.
J Environ Manage ; 95 Suppl: S325-31, 2012 Mar.
Article in English | MEDLINE | ID: mdl-21802196

ABSTRACT

The bacterial diversity and community structure were surveyed in intertidal petroleum-influenced sediments of ≈ 100 km of a beach, in the southern Gulf of Mexico. The beach was divided in twenty sampling sites according to high, moderate and low petroleum influence. Densities of cultured heterotrophic (HAB) and hydrocarbon degrading bacteria (HDB) were highly variable in sediments, with little morphological assortment in colonies. PCR-RISA banding patterns differentiated distinct communities along the beach, and the bacterial diversity changed inversely to the degree of petroleum hydrocarbon influence: the higher TPH concentration, the lower genotype diversity. Seven DNA sequences (Genbank EF191394 -EF191396 and EF191398 -EF191401) were affiliated to uncultured members of Gemmatimonas, Acidobacterium, Desulfobacteraceae, Rubrobacterales, Actinobacterium and the Fibrobacteres/Acidobacteria group; all the above taxa are known for having members with active roles in biogeochemical transformations. The remaining sequences (EF191388 - EF191393 and EF191397) affiliated to Pseudoalteromonas, and to oil-degrading genera such as Pseudomonas, Vibrio and Marinobacter, being the last one an obligate oil-degrading bacterium. An exchange of bacteria between the beach and the oil seep environment, and the potential cleaning-up role of bacteria at the southern Gulf of Mexico are discussed.


Subject(s)
Bacteria/genetics , Biodiversity , Geologic Sediments/microbiology , Petroleum Pollution/analysis , Acidobacteria/classification , Acidobacteria/genetics , Bacteria/classification , Environment , Fibrobacteres/classification , Fibrobacteres/genetics , Geologic Sediments/chemistry , Gulf of Mexico , Hydrocarbons/analysis , Marinobacter/classification , Marinobacter/genetics , Mexico , Phylogeny , Polymerase Chain Reaction
13.
Pak J Biol Sci ; 12(9): 683-9, 2009 May 01.
Article in English | MEDLINE | ID: mdl-19634471

ABSTRACT

The diversity of bacterial communities of shallow (< or = 100 m depth) oil seep marine sediments from the southern Gulf of Mexico was evaluated. The geochemical properties of seep sediments were characterized as well as their microbial diversity in oil seep and control sediments. Bacteria were identified through molecular tools as belonging to the genera Marinobacter, Idiomarina, Marinobacterium, Frauteria and an unknown bacterium. Bacteria might be important components of microbial communities in Total Petroleum Hydrocarbon (TPH)-containing environments, displaying either facultative metabolism or able to grow only in petroleum-containing media. The identification of bacteria in shallow oil seep sediments could be used as indicators of marine hydrocarbons in southeastern Gulf of Mexico.


Subject(s)
Bacteria , Biodiversity , Geologic Sediments/microbiology , Seawater , Bacteria/classification , Bacteria/genetics , Bacterial Typing Techniques , DNA, Bacterial/genetics , DNA, Ribosomal/genetics , Hydrocarbons/chemistry , Mexico , Phylogeny , Water Microbiology
14.
Phys Rev E Stat Nonlin Soft Matter Phys ; 77(5 Pt 1): 051801, 2008 May.
Article in English | MEDLINE | ID: mdl-18643091

ABSTRACT

We investigate the effects of clay proportion and nanoscale dispersion in the dielectric response of poly(vinyl alcohol)-bentonite nanocomposites. The dielectric study was performed using the thermally stimulated depolarization current technique, covering the temperature range of the secondary and high-temperature relaxation processes. Important changes in the secondary relaxations are observed at low clay contents in comparison with neat poly(vinyl alcohol) (PVA). The high-temperature processes show a complex peak, which is a combination of the glass-rubber transition and the space-charge relaxations. The analysis of these processes shows the existence of two segmental relaxations for the nanocomposites. Dielectric results were complemented by calorimetric experiments using differential scanning calorimetry. Morphologic characterization was performed by x-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM and XRD results show a mixture of intercalated and exfoliated clay dispersion in a trend that promotes the exfoliated phase as the bentonite content diminishes. Dielectric and morphological results indicate the existence of polymer-clay interactions through the formation of hydrogen bounds and promoted by the exfoliated dispersion of the clay. These interactions affect not only the segmental dynamics, but also the secondary local dynamics of PVA.

15.
MEDICC Rev ; 10(2): 14-20, 2008 04.
Article in English | MEDLINE | ID: mdl-21483363

ABSTRACT

Introduction: Obesity is a social disease constituting a global pandemic. It is present in 90% of diabetic and 65% of hypertensive patients. It is associated with cardiometabolic syndrome and with damaging physiopathological mechanisms, particularly for the vascular system and the kidneys. On Cuba's Isle of Youth, a community-based epidemiological study of chronic kidney disease (CKD), hypertension (HTN), diabetes mellitus (DM) and cardio-cerebral vascular disease was carried out in total population, including an examination of common risk factors. Objective: Based on the Isle of Youth Study (ISYS) data, determine prevalence of obesity and overweight, and their association with CKD, HTN, DM, and shared risk factors for all these conditions in total population of the Isle of Youth, Cuba. Methods: Phase 1: Population diagnosis (November 2004-April 2006): 96.6% of the Isle of Youth's total population (80,117) was studied, including all ages and both sexes. Information was offered to the public, and written informed consent obtained. Screening was conducted by participant questionnaire including risk factors, physical measurements (weight, height, blood pressure and body mass index), and a single first-morning urine sample to determine the presence of vascular-renal damage markers ­ proteinuria and hematuria (Combur 10 Test, Roche), and microalbuminuria (Micral Test, Roche). When results were positive, serum creatinine was determined and glomerular filtration rate (GFR) estimated with Modification of Diet in Renal Disease (MDRD) formula for adults and Schwartz formula for children <15 years. Data obtained were analyzed to determine association of participants' nutritional status with prevalence of chronic kidney disease, hypertension and diabetes mellitus, as well as a set of common risk factors. Results: Population <20 years: Obesity prevalence 3.2%; positive urine markers in 56.9% of obese and 8.9% of non-obese participants; positive albuminuria in 38% of obese and 3% of non-obese. Obese participants were found to be hyperfiltrating. DM prevalence was 9.5% in obese and 1.1% in non-obese participants. Population ≥20 years: Overweight, 31.3%; obese, 13.4%. Positive markers in normal-weight, overweight and obese individuals were 18.3%, 21.2% and 32.7%, respectively; microalbuminuria values increased with weight. Obese individuals were found to be hyperfiltrating. HTN prevalence in normal-weight, overweight and obese individuals was 18.3%, 31.5%, and 51.0% respectively; DM rates were 2.8%, 5.2% y 11.3%, respectively. Conclusion: In Cuba, obesity poses significant risk for vascular and renal damage and should be the focus of increased prevention efforts.

16.
Biomacromolecules ; 8(3): 941-8, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17261065

ABSTRACT

In the present work, we have studied the effect of the piezoelectricity of elastically deformed cortical bone collagen on surface using a biomimetic approach. The mineralization process induced as a consequence of the piezoelectricity effect was evaluated using scanning electron microscopy (SEM), thermally stimulated depolarization current (TSDC), and differential scanning calorimetry (DSC). SEM micrographs showed that mineralization occurred predominantly over the compressed side of bone collagen, due to the effect of piezoelectricity, when the sample was immersed in the simulated body fluid (SBF) in a cell-free system. The TSDC method was used to examine the complex collagen dielectric response. The dielectric spectra of deformed and undeformed collagen samples with different hydration levels were compared and correlated with the mineralization process followed by SEM. The dielectric measurements showed that the mineralization induced significant changes in the dielectric spectra of the deformed sample. DSC and TSDC results demonstrated a reduction of the collagen glass transition as the mineralization process advanced. The combined use of SEM, TSDC, and DSC showed that, even without osteoblasts present, the piezoelectric dipoles produced by deformed collagen can produce the precipitation of hydroxyapatite by electrochemical means, without a catalytic converter as occurs in classical biomimetic deposition.


Subject(s)
Biocompatible Materials/chemistry , Bone and Bones/metabolism , Collagen/chemistry , Durapatite/chemistry , Animals , Biomimetics , Calorimetry, Differential Scanning , Electrochemistry/methods , Extracellular Matrix/metabolism , Macromolecular Substances , Microscopy, Electron, Scanning , Osteoblasts/metabolism , Rabbits , Temperature
17.
Rev. cuba. med ; 44(5-6)sept.-dic. 2005. tab
Article in Spanish | CUMED | ID: cum-33277

ABSTRACT

La desnutrición en el paciente con cáncer avanzado favorece la inmunosupresión e implica un bajo índice de Karnofsky, pobre tolerancia y respuesta a los tratamientos oncoespecíficos, ya sea con intención curativa o paliativa, alta susceptibilidad a las infecciones y, por tanto, disminuye la calidad de vida. Los pacientes con tumores localizados en cabeza y cuello en etapas avanzadas (III-IV), constituyen uno de los grupos de alto riesgo de malnutrición por la reducción de ingresos de nutrientes, la anorexia, alteraciones del mecanismo de la deglución, obstrucción mecánica de las vías digestivas superiores, entre otras. Numerosos estudios demuestran la conveniencia del soporte nutricional en estos pacientes durante el tratamiento oncoespecífico. Se realizó un estudio prospectivo que incluyó 15 pacientes con neoplasias localizadas en cabeza y cuello en etapas avanzadas, clínicamente con signos de malnutrición, para evaluar el aporte calórico-energético adicional; a todos se les administró un soporte nutricional oral (Adn-22 por ciento) durante el tratamiento radiante para evaluar la posibilidad de mejoría en cuanto a la tolerancia y respuesta al tratamiento. De los 15 casos estudiados, 13 presentaron complicaciones al tratamiento, pero en su mayoría de ligera intensidad, sin afectar de forma significativa el tiempo de duración y la dosis total de tratamiento, con respuesta favorable en relación con el tumor(AU)


Subject(s)
Humans , Nutritional Support/methods , Nutritional Support/statistics & numerical data , Radiation, Ionizing , Protein-Energy Malnutrition/therapy , Head and Neck Neoplasms/complications
18.
Rev. cuba. med ; 44(5/6)sep.-dic. 2005.
Article in Spanish | LILACS | ID: lil-628853

ABSTRACT

La desnutrición en el paciente con cáncer avanzado favorece la inmunosupresión e implica un bajo índice de Karnofsky, pobre tolerancia y respuesta a los tratamientos oncoespecíficos, ya sea con intención curativa o paliativa, alta susceptibilidad a las infecciones y, por tanto, disminuye la calidad de vida. Los pacientes con tumores localizados en cabeza y cuello en etapas avanzadas (III-IV), constituyen uno de los grupos de alto riesgo de malnutrición por la reducción de ingresos de nutrientes, la anorexia, alteraciones del mecanismo de la deglución, obstrucción mecánica de las vías digestivas superiores, entre otras. Numerosos estudios demuestran la conveniencia del soporte nutricional en estos pacientes durante el tratamiento oncoespecífico. Se realizó un estudio prospectivo que incluyó 15 pacientes con neoplasias localizadas en cabeza y cuello en etapas avanzadas, clínicamente con signos de malnutrición, para evaluar el aporte calórico-energético adicional; a todos se les administró un soporte nutricional oral (Adn-22 %) durante el tratamiento radiante para evaluar la posibilidad de mejoría en cuanto a la tolerancia y respuesta al tratamiento. De los 15 casos estudiados, 13 presentaron complicaciones al tratamiento, pero en su mayoría de ligera intensidad, sin afectar de forma significativa el tiempo de duración y la dosis total de tratamiento, con respuesta favorable en relación con el tumor.


Malnutrition in the patient with advanced cancer favors immunosuppresion and implies a low Karnofsky index, poor tolerance and response to the oncospecific curative or palliative treatments, high susceptibility to infections and, as a result, a decline of the quality of life. Patients with head and neck tumors in advanced stages (III-IV) are one of the groups of high risk for malnutrition due to the reduction of the intake of nutrients, anorexia, alterations of the deglution mechanism, and mechanical obstruction of the upper digestive tract, among other causes.Numerous studies show the convenience of the nutritional supplement in these patients during the oncospecific treatment. A prospective study that included 15 patients with head and neck neoplasias in advanced stages, and with clinical signs of malnutrition, was conducted in order to evaluate the necessary calorie-energy supplement. All of them were administered an oral nutritional supplement (Adn-22 %) during the radiation treatment to assess the possibility of improving their tolerance and response to the treatment. Of the 15 studied cases, 13 presented complications in connection with the treatment, but most them were mild, and they did not affect in a significant way the time of duration and the total dose of treatment. There was a favorable response in relation to the tumor.

SELECTION OF CITATIONS
SEARCH DETAIL