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1.
Ecotoxicol Environ Saf ; 271: 115981, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38242046

RESUMEN

To better understand the fate and assess the ingestible fraction of microplastics (by aquatic organisms), it is essential to quantify and characterize of their released from larger items under environmental realistic conditions. However, the current information on the fragmentation and size-based characteristics of released microplastics, for example from bio-based thermoplastics, is largely unknown. The goal of our work was to assess the fragmentation and release of microplastics, under ultraviolet (UV) radiation and in seawater, from polylactic acid (PLA) items, a bio-based polymer, and from polypropylene (PP) items, a petroleum-based polymer. To do so, we exposed pristine items of PLA and PP, immersed in filtered natural seawater, to accelerated UV radiation for 57 and 76 days, simulating 18 and 24 months of mean natural solar irradiance in Europe. Our results indicated that 76-day UV radiation induced the fragmentation of parent plastic items and the microplastics (50 - 5000 µm) formation from both PP and PLA items. The PP samples (48 ± 26 microplastics / cm2) released up to nine times more microplastics than PLA samples (5 ± 2 microplastics / cm2) after a 76-day UV exposure, implying that the PLA tested items had a lower fragmentation rate than PP. The particles' length of released microplastics was parameterized using a power law exponent (α), to assess their size distribution. The obtained α values were 3.04 ± 0.11 and 2.54 ± 0.06 (-) for 76-day UV weathered PP and PLA, respectively, meaning that PLA microplastics had a larger sized microplastics fraction than PP particles. With respect to their two-dimensional shape, PLA microplastics also had lower width-to-length ratio (0.51 ± 0.17) and greater fiber-shaped fractions (16%) than PP microplastics (0.57 ± 0.17% and 11%, respectively). Overall, the bio-based PLA items under study were more resistant to fragmentation and release of microplastics than the petroleum-based PP tested items, and the parameterized characteristics of released microplastics were polymer-dependent. Our work indicates that even though bio-based plastics may have a slower release of fragmented particles under UV radiation compared to conventional polymer types, they still have the potential to act as a source of microplastics in the marine environment, with particles being available to biota within ingestible size fractions, if not removed before major fragmentation processes.


Asunto(s)
Petróleo , Contaminantes Químicos del Agua , Polipropilenos , Microplásticos , Plásticos , Rayos Ultravioleta , Inmersión , Poliésteres , Agua de Mar , Polímeros , Contaminantes Químicos del Agua/análisis
2.
Sci Rep ; 10(1): 3047, 2020 02 20.
Artículo en Inglés | MEDLINE | ID: mdl-32080305

RESUMEN

The springtail, Megaphorura arctica, is freeze-avoiding and survives sub-zero temperatures by cryoprotective dehydration. At the onset of dehydration there is some supercooling of body fluids, and the danger of inoculative freezing, which would be lethal. To see if the springtails are protected by antifreeze proteins in this pre-equilibrium phase, we examined extracts from cold-acclimated M. arctica and recorded over 3 °C of freezing point depression. Proteins responsible for this antifreeze activity were isolated by ice affinity. They comprise isoforms ranging from 6.5 to 16.9 kDa, with an amino acid composition dominated by glycine (>35 mol%). Tryptic peptide sequences were used to identify the mRNA sequence coding for the smallest isoform. This antifreeze protein sequence has high similarity to one characterized in Hypogastrura harveyi, from a different springtail order. If these two antifreeze proteins are true homologs, we suggest their origin dates back to the Permian glaciations some 300 million years ago.


Asunto(s)
Proteínas Anticongelantes/metabolismo , Artrópodos/fisiología , Crioprotectores/metabolismo , Deshidratación/metabolismo , Congelación , Secuencia de Aminoácidos , Animales , Proteínas Anticongelantes/química , Cristalización , ADN Complementario/genética , Glicina/metabolismo , Modelos Moleculares , Isoformas de Proteínas/metabolismo
3.
Br J Nutr ; 121(6): 678-687, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30912737

RESUMEN

The second year of life is a period of nutritional vulnerability. We aimed to investigate the dietary patterns and nutrient intakes from 1 to 2 years of age during the 12-month follow-up period of the Growing Up Milk - Lite (GUMLi) trial. The GUMLi trial was a multi-centre, double-blinded, randomised controlled trial of 160 healthy 1-year-old children in Auckland, New Zealand and Brisbane, Australia. Dietary intakes were collected at baseline, 3, 6, 9 and 12 months post-randomisation, using a validated FFQ. Dietary patterns were identified using principal component analysis of the frequency of food item consumption per d. The effect of the intervention on dietary patterns and intake of eleven nutrients over the duration of the trial were investigated using random effects mixed models. A total of three dietary patterns were identified at baseline: 'junk/snack foods', 'healthy/guideline foods' and 'breast milk/formula'. A significant group difference was observed in 'breast milk/formula' dietary pattern z scores at 12 months post-randomisation, where those in the GUMLi group loaded more positively on this pattern, suggesting more frequent consumption of breast milk. No difference was seen in the other two dietary patterns. Significant intervention effects were seen on nutrient intake between the GUMLi (intervention) and cows' milk (control) groups, with lower protein and vitamin B12, and higher Fe, vitamin D, vitamin C and Zn intake in the GUMLi (intervention) group. The consumption of GUMLi did not affect dietary patterns, however, GUMLi participants had lower protein intake and higher Fe, vitamins D and C and Zn intake at 2 years of age.


Asunto(s)
Dieta , Alimentos Fortificados , Fórmulas Infantiles , Leche , Animales , Australia , Bovinos , Encuestas sobre Dietas , Método Doble Ciego , Ingestión de Energía , Conducta Alimentaria , Femenino , Estudios de Seguimiento , Humanos , Lactante , Fenómenos Fisiológicos Nutricionales del Lactante , Estudios Longitudinales , Masculino , Nueva Zelanda , Necesidades Nutricionales , Resultado del Tratamiento
4.
J Nutr ; 148(10): 1570-1579, 2018 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-30281106

RESUMEN

Background: Iron deficiency (ID) and vitamin D deficiency (VDD) are significant pediatric health issues in New Zealand and Australia and remain prevalent micronutrient deficiencies in young children globally. Objective: We aimed to investigate the effect of a micronutrient-fortified, reduced-energy growing-up milk (GUMLi) compared with cow milk (CM) consumed for 1 y on dietary iron and vitamin D intakes and the status of New Zealand and Australian children at 2 y of age. Methods: The GUMLi Trial was a multicenter, double-blind, randomized controlled trial in 160 healthy 1-y-old New Zealand and Australian children conducted in 2015-2017. Participants were randomly assigned 1:1 to receive GUMLi (1.7 mg Fe/100 mL; 1.3 µg cholecalciferol/100 mL) or CM (0.02 mg Fe/100 mL; 0.06 µg cholecalciferol/100 mL) for 12 mo. Secondary outcomes, reported here, included change in dietary iron and vitamin D intakes, iron status, and 25-hydroxyvitamin D [25(OH)D] concentrations from blood samples at age 2 y. All regression models were adjusted for baseline outcome and study center. Results: GUMLi was a large contributor to dietary intakes of iron and vitamin D after 12 mo when compared with intakes from food and CM. The adjusted mean difference between groups for serum ferritin concentrations was 17.8 µg/L (95% CI: 13.6, 22.0 µg/L; P < 0.0001), and for 25(OH)D it was 16.6 nmol/L (95% CI: 9.9, 23.3 nmol/L; P < 0.0001). After 12 mo, ID was present in 16 (24%) participants in the CM group and 5 (7%) participants in the GUMLi group (P = 0.009), and the prevalence of VDD in the CM group increased to 14% (n = 10) and decreased to 3% (n = 2) (P = 0.03) in the GUMLi group. Conclusion: In comparison with CM, GUMLi significantly improved dietary iron and vitamin D intakes and the iron and vitamin D status of healthy children at 2 y of age. This trial was registered with the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au) as ACTRN12614000918628.


Asunto(s)
Anemia Ferropénica/prevención & control , Alimentos Fortificados , Hierro/uso terapéutico , Leche , Estado Nutricional , Deficiencia de Vitamina D/prevención & control , Vitamina D/uso terapéutico , Anemia Ferropénica/sangre , Animales , Preescolar , Colecalciferol/sangre , Colecalciferol/uso terapéutico , Dieta , Suplementos Dietéticos , Método Doble Ciego , Femenino , Humanos , Hierro/sangre , Hierro de la Dieta/sangre , Hierro de la Dieta/uso terapéutico , Masculino , Micronutrientes/sangre , Micronutrientes/uso terapéutico , Vitamina D/análogos & derivados , Vitamina D/sangre , Deficiencia de Vitamina D/sangre , Vitaminas/sangre
5.
Appl Environ Microbiol ; 83(15)2017 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-28526788

RESUMEN

Zinc resistance in livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) sequence type 398 (ST398) is primarily mediated by the czrC gene colocated with the mecA gene, encoding methicillin resistance, within the type V staphylococcal cassette chromosome mec (SCCmec) element. Because czrC and mecA are located within the same mobile genetic element, it has been suggested that the use of zinc in feed as an antidiarrheal agent has the potential to contribute to the emergence and spread of methicillin-resistant S. aureus (MRSA) in swine, through increased selection pressure to maintain the SCCmec element in isolates obtained from pigs. In this study, we report the prevalence of the czrC gene and phenotypic zinc resistance in U.S. swine-associated LA-MRSA ST5 isolates, MRSA ST5 isolates from humans with no swine contact, and U.S. swine-associated LA-MRSA ST398 isolates. We demonstrated that the prevalence of zinc resistance in U.S. swine-associated LA-MRSA ST5 isolates was significantly lower than the prevalence of zinc resistance in MRSA ST5 isolates from humans with no swine contact and swine-associated LA-MRSA ST398 isolates, as well as prevalences from previous reports describing zinc resistance in other LA-MRSA ST398 isolates. Collectively, our data suggest that selection pressure associated with zinc supplementation in feed is unlikely to have played a significant role in the emergence of LA-MRSA ST5 in the U.S. swine population. Additionally, our data indicate that zinc resistance is associated with the multilocus sequence type lineage, suggesting a potential link between the genetic lineage and the carriage of resistance determinants.IMPORTANCE Our data suggest that coselection thought to be associated with the use of zinc in feed as an antimicrobial agent is not playing a role in the emergence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) ST5 in the U.S. swine population. Additionally, our data indicate that zinc resistance is more associated with the multilocus sequence type lineage, suggesting a potential link between the genetic lineage and the carriage of resistance markers. This information is important for public health professionals, veterinarians, producers, and consumers.


Asunto(s)
Antibacterianos/farmacología , Resistencia a la Meticilina , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/veterinaria , Enfermedades de los Porcinos/microbiología , Zinc/farmacología , Animales , Humanos , Meticilina/farmacología , Staphylococcus aureus Resistente a Meticilina/clasificación , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Tipificación de Secuencias Multilocus , Filogenia , Prevalencia , Infecciones Estafilocócicas/epidemiología , Porcinos , Enfermedades de los Porcinos/epidemiología , Estados Unidos/epidemiología
6.
Public Health Nutr ; 20(7): 1214-1225, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-27938461

RESUMEN

OBJECTIVE: Adequate nutrition is critical for optimal growth and development. However, young children may be at risk of nutrient deficiencies when transitioning to weaning foods for a variety of reasons. Supplementation with fortified milk may provide potentially lacking essential nutrients, but effects on growth and nutritional status are yet to be established. DESIGN: Five databases were searched for randomised controlled trials using fortified milk against control milk in young children. Outcomes were growth, body composition and/or biochemical markers. Pooled differences in means were calculated for continuous outcomes and odds ratios for binary outcomes. SETTING: Randomised controlled trials set in any country. SUBJECTS: Otherwise healthy children aged 6-47 months. RESULTS: Fifteen articles met the eligibility criteria. Fortification varied from Fe, Zn, vitamins, essential fatty acids, to pre- and/or probiotics. Frequently reported outcomes were weight, height and Fe status. Studies varied in geographical location, sample size and duration. Fortified milk had minimal effects on weight gain (mean difference=0·17 kg; 95 % CI 0·02, 0·31 kg) compared with control milk. The risk of anaemia was reduced in fortified milk groups (OR=0·32; 95 % CI 0·15, 0·66) compared with control groups. There were no significant effects on height gain, changes in body composition or Hb concentration. CONCLUSIONS: Fortified milk is an effective source of complementary nutrition to supplement children in need when consumed in appropriate amounts in addition to a normal diet. Due to compositional differences, further research on fortified milk is warranted before making global recommendations on benefits for growth and nutritional outcomes in young children.


Asunto(s)
Desarrollo Infantil , Alimentos Fortificados , Leche/química , Estado Nutricional , Anemia Ferropénica/sangre , Anemia Ferropénica/prevención & control , Animales , Biomarcadores/sangre , Composición Corporal , Peso Corporal , Preescolar , Humanos , Lactante , Micronutrientes/administración & dosificación , Micronutrientes/sangre , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Riesgo , Sensibilidad y Especificidad , Resultado del Tratamiento
7.
Ann Nutr Metab ; 67(2): 119-32, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26360877

RESUMEN

BACKGROUND: There are no internationally agreed recommendations on compositional requirements of follow-up formula for young children (FUF-YC) aged 1-3 years. AIM: The aim of the study is to propose international compositional recommendations for FUF-YC. METHODS: Compositional recommendations for FUF-YC were devised by expert consensus based on a detailed literature review of nutrient intakes and unmet needs in children aged 12-36 months. RESULTS AND CONCLUSIONS: Problematic nutrients with often inadequate intakes are the vitamins A, D, B12, C and folate, calcium, iron, iodine and zinc. If used, FUF-YC should be fed along with an age-appropriate mixed diet, usually contributing 1-2 cups (200-400 ml) of FUF-YC daily (approximately 15% of total energy intake). Protein from cow's milk-based formula should provide 1.6-2.7 g/100 kcal. Fat content should be 4.4-6.0 g/100 kcal. Carbohydrate should contribute 9-14 g/100 kcal with >50% from lactose. If other sugars are added, they should not exceed 10% of total carbohydrates. Calcium should provide 200 mg/100 kcal. Other micronutrient contents/100 kcal should reach 15% of the World Health Organization/Food and Agriculture Organization recommended nutrient intake values. A guidance upper level that was 3-5 times of the minimum level was established. Countries may adapt compositional requirements, considering recommended nutrient intakes, habitual diets, nutritional status and existence of micronutrient programs to ensure adequacy while preventing excessive intakes.


Asunto(s)
Fórmulas Infantiles/química , Fórmulas Infantiles/normas , Fenómenos Fisiológicos Nutricionales del Lactante/normas , Academias e Institutos , Preescolar , Carbohidratos de la Dieta/análisis , Grasas de la Dieta/análisis , Ingestión de Energía , Estudios de Seguimiento , Humanos , Lactante , Lactosa/administración & dosificación , Lactosa/análisis , Micronutrientes/análisis , Micronutrientes/deficiencia , Proteínas de la Leche/administración & dosificación , Proteínas de la Leche/análisis , Estado Nutricional , Ensayos Clínicos Controlados Aleatorios como Asunto , Ingesta Diaria Recomendada/legislación & jurisprudencia , Tailandia
8.
Nutr Res ; 33(10): 781-8, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24074735

RESUMEN

Although obesity is a key predisposing risk factor in the development of insulin resistance (IR) and type 2 diabetes mellitus, not all obese individuals develop IR. This study aimed to identify key anthropometric and biochemical parameters that predict insulin sensitivity in overweight and obese adults. Based on previous literature, we hypothesized that markers of insulin sensitivity would be negatively correlated with plasma concentrations of free fatty acids and liver enzymes. Forty nondiabetic adult participants (body mass index ≥ 25.0 kg/m²) were recruited. Data collection included anthropometric measurements and fasting plasma samples for the quantification of liver enzymes (alanine transaminase, aspartate transaminase, γ-glutamyl transpeptidase), blood lipid profile, and markers of insulin sensitivity. Questionnaires relating to dietary intake, physical activity, and fatigue were also completed. Insulin and Homeostasis Model of Assessment (HOMA) scores were significantly correlated with indirect measures of central obesity (P < .05). Glycosylated hemoglobin, insulin, and HOMA scores for IR were all positively correlated with selected liver function markers (P < .05). Scores of HOMA-IR were significantly positively correlated with plasma phospholipid levels of n-3 fatty acids (P = .04) and ratio of n-3/n-6 fatty acids (P < .05) and negatively correlated with n-6 fatty acids (P = .03). No significant correlations were found between markers of insulin sensitivity and cholesterol levels, physical activity, or self-reported fatigue. These results have reinforced the integral role of liver function in the development of IR. Despite previous data linking elevations in free fatty acid to the development of IR, we found no relationship between these variables in this study.


Asunto(s)
Índice de Masa Corporal , Ácidos Grasos no Esterificados/sangre , Hemoglobina Glucada/metabolismo , Resistencia a la Insulina , Insulina/sangre , Hígado/fisiopatología , Obesidad/fisiopatología , Adulto , Alanina Transaminasa/sangre , Aspartato Aminotransferasas/sangre , Biomarcadores/sangre , Colesterol/sangre , Diabetes Mellitus , Ejercicio Físico/fisiología , Fatiga/metabolismo , Ácidos Grasos Omega-3/sangre , Ácidos Grasos Omega-6/sangre , Femenino , Humanos , Hígado/enzimología , Masculino , Persona de Mediana Edad , Obesidad/sangre , Obesidad/enzimología , Obesidad Abdominal/sangre , Obesidad Abdominal/enzimología , Obesidad Abdominal/fisiopatología , Sobrepeso , Fosfolípidos/sangre , Valores de Referencia , gamma-Glutamiltransferasa/sangre
9.
Cardiovasc Res ; 99(2): 315-27, 2013 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-23619421

RESUMEN

Atherosclerosis initiates at predictable focal sites and develops to a spatially regional disease with limited distribution. There is compelling evidence that links haemodynamics to the localized origin of atherosclerotic lesions. Arterial flow in vivo is unsteady, dynamically complex, and regionally variable. Sites susceptible to atherosclerosis near arterial branches and curves are associated with regions of disturbed blood flow that contain repetitive phases of flow reversal resulting in steep multidirectional temporal and spatial gradients of wall shear stresses. Endothelium in atherosusceptible regions relative to protected sites shows activation of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR), the altered expression of pro-inflammatory Nuclear Factor kappa B (NFκB) and oxidant/antioxidant pathways, and low expression of major protective factors, notably endothelial nitric oxide synthase and Kruppel-like Factors KLF2 and KLF4. At some atherosusceptible locations, reactive oxygen species levels are significantly elevated. Here we describe flow-related phenotypes identified in steady-state in vivo and outline some of the molecular mechanisms that may contribute to pre-lesional atherosusceptibility as deduced from complementary cell experiments in vitro. We conclude that disturbed flow is a significant local risk factor for atherosclerosis that induces a chronic low-level inflammatory state, an adaptive response to ensure continued function at the expense of increased susceptibility to atherogenesis. Surprisingly, when challenged by short-term hypercholesterolaemia in vivo, atherosusceptible endothelial phenotype was resistant to greater pro-inflammatory expression, suggesting that sustained hyperlipidaemia is required to overcome these protective characteristics.


Asunto(s)
Aterosclerosis/fisiopatología , Endotelio Vascular/fisiopatología , Hemodinámica , Mecanotransducción Celular , Animales , Aterosclerosis/metabolismo , Aterosclerosis/patología , Fenómenos Biomecánicos , Células Endoteliales/metabolismo , Células Endoteliales/patología , Endotelio Vascular/metabolismo , Endotelio Vascular/patología , Humanos , Hipercolesterolemia/metabolismo , Hipercolesterolemia/patología , Hipercolesterolemia/fisiopatología , Inflamación/metabolismo , Inflamación/patología , Inflamación/fisiopatología , Factor 4 Similar a Kruppel , Fenotipo , Flujo Sanguíneo Regional , Estrés Mecánico
11.
Trop Med Int Health ; 15(12): 1481-90, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20958890

RESUMEN

OBJECTIVE: To assess the efficacy of weekly zinc or zinc plus retinol as adjuncts for the treatment of pulmonary tuberculosis. METHODS: Double-blind, randomized, placebo-controlled trial in 350 patients >15 years old with smear-positive tuberculosis in Nigeria (ISRCTN36636609). In addition to antituberculous treatment, patients were randomly allocated to weekly supplements of zinc (90 mg), zinc plus retinol (5000 IU) or placebos for 6 months. Primary outcomes were time to sputum smear conversion and resolution of radiographic abnormalities. RESULTS: After 8 weeks of treatment, 68% had achieved sputum smear conversion, and the median conversion time was 6.5 weeks. Hazard ratios (HR, 95%CI) for sputum conversion relative to the placebo group were not significant for zinc (1.07, 0.92-1.29) or zinc plus retinol (0.89, 0.76-1.07). Significant predictors of time to sputum conversion were lung abnormality score, sputum smear grade, age and serum C-reactive protein. HIV co-infection and gender were not independent predictors of time to sputum conversion. There were no significant differences between supplement groups in clinical, radiological or laboratory outcomes at 2 months or 6 months. There were 9, 9 and 2 deaths in patients receiving zinc, zinc plus retinol or placebos, respectively. Mortality in those who received zinc (HR 1.71, 0.88-3.58) or zinc plus retinol (HR 1.54, 0.78-3.26) did not differ significantly from those who received placebos. Most deaths occurred in patients co-infected with HIV. CONCLUSIONS: Supplementation with zinc or zinc plus retinol did not lead to better outcomes than placebos, and caution is warranted regarding routine micronutrient supplementation, particularly in patients co-infected with HIV.


Asunto(s)
Antituberculosos/uso terapéutico , Suplementos Dietéticos , Tuberculosis Pulmonar/tratamiento farmacológico , Vitamina A/uso terapéutico , Zinc/uso terapéutico , Adolescente , Adulto , Tos/microbiología , Método Doble Ciego , Esquema de Medicación , Quimioterapia Combinada , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/aislamiento & purificación , Radiografía , Esputo/microbiología , Resultado del Tratamiento , Tuberculosis Pulmonar/complicaciones , Tuberculosis Pulmonar/diagnóstico por imagen , Adulto Joven
13.
Am J Physiol Cell Physiol ; 289(5): C1134-44, 2005 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15958527

RESUMEN

Inward rectifier K(+) channels (Kir) are a significant determinant of endothelial cell (EC) membrane potential, which plays an important role in endothelium-dependent vasodilatation. In the present study, several complementary strategies were applied to determine the Kir2 subunit composition of human aortic endothelial cells (HAECs). Expression levels of Kir2.1, Kir2.2, and Kir2.4 mRNA were similar, whereas Kir2.3 mRNA expression was significantly weaker. Western blot analysis showed clear Kir2.1 and Kir2.2 protein expression, but Kir2.3 protein was undetectable. Functional analysis of endothelial inward rectifier K(+) current (I(K)) demonstrated that 1) I(K) current sensitivity to Ba(2+) and pH were consistent with currents determined using Kir2.1 and Kir2.2 but not Kir2.3 and Kir2.4, and 2) unitary conductance distributions showed two prominent peaks corresponding to known unitary conductances of Kir2.1 and Kir2.2 channels with a ratio of approximately 4:6. When HAECs were transfected with dominant-negative (dn)Kir2.x mutants, endogenous current was reduced approximately 50% by dnKir2.1 and approximately 85% by dnKir2.2, whereas no significant effect was observed with dnKir2.3 or dnKir2.4. These studies suggest that Kir2.2 and Kir2.1 are primary determinants of endogenous K(+) conductance in HAECs under resting conditions and that Kir2.2 provides the dominant conductance in these cells.


Asunto(s)
Células Endoteliales/metabolismo , Regulación de la Expresión Génica/fisiología , Canales de Potasio de Rectificación Interna/biosíntesis , Aorta/citología , Bario/farmacología , Membrana Celular/fisiología , Células Cultivadas , Células Endoteliales/efectos de los fármacos , Humanos , Concentración de Iones de Hidrógeno , Potenciales de la Membrana/fisiología , Potasio/metabolismo , ARN Mensajero/biosíntesis
14.
Mar Pollut Bull ; 51(1-4): 174-85, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15757719

RESUMEN

Nutrient and suspended sediment concentrations were measured in the dry season and during the rising and falling stages of flood events in the Annan and Daintree rivers to estimate catchment exports. These flood events were also sampled along the salinity gradient in the estuary and nearshore shelf to quantify the modification of terrestrial sediment and nutrient loads as they pass through estuaries into the Great Barrier Reef lagoon. In the Daintree River TSS concentrations were found to increase between the catchment and the estuary plume. The source of TSS may have been scour of the estuarine channel or from land use in the catchment of the lower estuary. In the dry season nitrogen enters the Annan and Daintree estuaries predominantly in the form of PON and DON in roughly equal proportions. Nitrogen exports to the GBR are mostly in the form of DON. In the wet season the majority of nitrogen enters the estuaries as DON and leaves as PON. Nitrogen removal in the estuaries and plumes appears to be biologically mediated once suspended sediment concentrations decrease to a point where phytoplankton growth is not light limited. In the dry season phosphorus enters and leaves the estuaries primarily in organic form. PIP is the dominant form of phosphorus in river water, but leaves the estuary more evenly distributed between all forms. These estuarine processes result in less nitrogen and phosphorus being delivered to the GBR lagoon than is exported from the catchment. The differences between these estuaries highlights the need for further work to explore modifications in estuaries that drain into the Great Barrier Reef lagoon.


Asunto(s)
Conservación de los Recursos Naturales , Sedimentos Geológicos/química , Nitrógeno/análisis , Fósforo/análisis , Animales , Antozoos , Desastres , Ecosistema , Monitoreo del Ambiente , Queensland , Ríos , Movimientos del Agua
15.
Plant Physiol ; 132(1): 106-17, 2003 May.
Artículo en Inglés | MEDLINE | ID: mdl-12746517

RESUMEN

Potato (Solanum tuberosum) homeobox 1 (POTH1) is a class I homeobox gene isolated from an early-stage tuber cDNA library. The RNA expression pattern of POTH1, unlike that of most other class I knotted-like homeobox genes, is widespread in the cells of both indeterminate and differentiated tissues. Using in situ hybridization, POTH1 transcripts were detected in meristematic cells, leaf primordia, and the vascular procambium of the young stem. Overexpression of POTH1 produced dwarf plants with altered leaf morphology. Leaves were reduced in size and displayed a "mouse-ear" phenotype. The mid-vein was less prominent, resulting in a palmate venation pattern. The overall plant height of overexpression lines was reduced due to a decrease in internode length. Levels of intermediates in the gibberellin (GA) biosynthetic pathway were altered, and the bioactive GA, GA(1), was reduced by one-half in sense mutants. Accumulation of mRNA for GA 20-oxidase1, a key biosynthetic enzyme, decreased in overexpression lines. In vitro tuberization was enhanced under both short- and long-day photoperiods in several POTH1 overexpression lines. Sense lines produced more tubers at a faster rate than controls. These results imply that POTH1 mediates the development of potato by acting as a negative regulator of GA biosynthesis.


Asunto(s)
Giberelinas/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Plantas/genética , Solanum tuberosum/genética , Northern Blotting , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Proteínas de Homeodominio/metabolismo , Hibridación in Situ , Datos de Secuencia Molecular , Fenotipo , Filogenia , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , ARN Mensajero/genética , ARN Mensajero/metabolismo , Solanum tuberosum/crecimiento & desarrollo
16.
FEBS Lett ; 532(3): 401-6, 2002 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-12482600

RESUMEN

Limb girdle muscular dystrophy type 2A is linked to a skeletal muscle-specific calpain isoform known as p94. Isolation of the intact 94-kDa enzyme has been difficult to achieve due to its rapid autolysis, and uncertainty has arisen over its Ca2+-dependence for activity. We have expressed a C-terminally truncated form of the enzyme that comprises the protease core (domains I and II) along with its insertion sequence, IS1, and N-terminal leader sequence, NS. This 47-kDa p94I-II mini-calpain was stable during purification. In the presence of Ca2+, p94I-II cleaved itself within the NS and IS1 sequences. Mapping of the autolysis sites showed that NS and IS1 have the potential to be removed without damage to the protease core. Ca2+-dependent autolysis must be an intramolecular event because the inactive p94I-II C129S mutant was not cleaved by incubation with wild-type p94I-II. In addition, the rate of autolysis of p94I-II was independent of the concentration of the enzyme.


Asunto(s)
Calcio/metabolismo , Calpaína/farmacología , Autólisis , Sitios de Unión , Clonación Molecular , Cisteína Endopeptidasas/metabolismo , ADN Complementario/metabolismo , Electroforesis en Gel de Poliacrilamida , Humanos , Músculo Esquelético/metabolismo , Mutagénesis Sitio-Dirigida , Péptidos/química , Plásmidos/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Tiempo
17.
Biochem J ; 367(Pt 1): 263-9, 2002 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-12014988

RESUMEN

The mu- and m-calpains are closely related Ca(2+)-dependent cysteine proteases having different in vitro Ca(2+) requirements ( K (d)), of approx. 25 and 325 microM respectively. The two isoforms are heterodimers of slightly different large (80 kDa) subunits and an identical small (28 kDa) subunit, so that the difference in K (d) values must reside in the large subunits. As assayed here, these K (d) values relate to the Ca(2+) required for the first phase of calpain activation and do not reflect the lower Ca(2+) then required by fully activated calpain. On the basis of sequence comparison and the X-ray structure of m-calpain, many m-type residues in the C-terminal EF-hand-containing domain IV were converted into the corresponding mu-type residues, but these mutations did not produce the expected decrease in K (d). In a series of hybrid (mu/m) large-subunit calpains, the K (d) values decreased progressively towards that of mu-calpain as the proportion of mu-type sequence increased from 0 to 90%. K (d) values cannot therefore be ascribed to one or a few specific intramolecular interactions, but reflect the global response of the whole molecule to Ca(2+) binding. Nonetheless, 25% of the difference in K (d) values between mu- and m-calpain can be ascribed to the N-terminal peptide of the large subunit, whereas the C-terminal EF-hand-containing domain IV accounts for 65% of the difference.


Asunto(s)
Calcio/metabolismo , Calpaína/metabolismo , Secuencia de Aminoácidos , Animales , Sitios de Unión , Calpaína/genética , Caseínas/metabolismo , ADN Complementario/metabolismo , Relación Dosis-Respuesta a Droga , Escherichia coli/metabolismo , Cinética , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Mutación , Plásmidos/metabolismo , Estructura Terciaria de Proteína , Ratas , Homología de Secuencia de Aminoácido
19.
Br. homoeopath. j ; 78(4): 2l0-3, Oct. 1989. tab
Artículo en Inglés | HomeoIndex | ID: hom-42

RESUMEN

Research was carried out to determine whether or not there was difference in the health beliefs, expectations and behaviour of a sample of 92 patients attending a dermatological or rheumatological outpatient clinic which offered either homoeopathic treatment (N=47) or conventional treatment (N=45). Self-administered questionnaires were used which examined patients'pathwaysto care, expectations, beliefs, behaviour and multidimensional health locus of control. The two key differences between those seeking homoeopathic and those seeking conventional medicine were in terms of their reasons for attending a homeopathic or conventional clinic, and their beliefs about their presenting dermatological or rheumatological condition


Asunto(s)
Humanos , Masculino , Femenino , Actitud Frente a la Salud , Hábitos , Conducta , Homeopatía , Practicas Alopaticas
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