RESUMEN
The objective of this study was to better understand the effect of butter composition and emulsion structure on growth and survival of Clostridium sporogenes, used as a surrogate for C. botulinum in canned butter. The lack of a thermal process step in commercially available canned butter raises questions of potential safety, because it is hermetically sealed and generally exhibits anaerobic growth conditions, which are optimal for Clostridium botulinum growth. Without thermal processing, low-acid canned foods must have inhibitory factors present to prevent C. botulinum growth. Some potential intrinsic inhibitory factors, or hurdles, within butter include: reduced water activity, acidity in cultured products, elevated salt content, and the micro-droplet nature of the aqueous phase in the butter emulsion. It was hypothesized that a normal, intact butter emulsion would have sufficient hurdles to prevent C. botulinum growth, whereas a broken butter emulsion would result in a coalesced aqueous phase that would allow for C. botulinum growth. Batch-churned butter was inoculated with C. sporogenes; butter samples with varying salt contents (0, 0.8, 1.6, and 2.4% wt/wt NaCl) were prepared and stored in coated steel cans for varying times (1 or 2 wk) and temperatures (22 or 41°C) to determine temperature and emulsion structure effects on C. sporogenes growth. Samples stored at 41°C showed a significant increase in C. sporogenes growth compared with those stored at 22°C. Furthermore, NaCl addition was found to have a significant effect on C. sporogenes growth, with 0.8% NaCl promoting more growth than 0%, but with decreases in growth observed at 1.6 and 2.4%. Uninoculated control plates were also found to have bacterial growth; this growth was attributed to other anaerobic bacteria present within the cream. It was concluded that removal of the hurdle created by the micro-droplet size of the emulsion aqueous phase could result in C. botulinum growth even at elevated salt levels and, therefore, home preparation of canned butter is not advisable. It is also possible that commercially canned butter, if heat abused, could potentially allow for C. botulinum growth and, therefore, consumption is not recommended.
Asunto(s)
Mantequilla/microbiología , Clostridium botulinum/crecimiento & desarrollo , Clostridium/crecimiento & desarrollo , Mantequilla/normas , Emulsiones , Calidad de los Alimentos , Tecnología de Alimentos/métodos , Microscopía ConfocalRESUMEN
Drosophila rdgC (retinal degeneration-C) mutants show normal retinal morphology and photoreceptor physiology at young ages. Dark-reared rdgC flies retain this wild-type phenotype, but light-reared mutants undergo retinal degeneration. rdgC photoreceptors with low levels of rhodopsin as a result of vitamin A deprivation or a mutant rhodopsin (ninaE) gene fail to show rdgC-induced degeneration even after prolonged light treatment, demonstrating that degeneration occurs as a result of light stimulation of rhodopsin. Analysis of norpA; rdgC flies shows that the norpA-encoded phospholipase C, the target enzyme of the G protein activated by rhodopsin, is not required for rdgC-induced degeneration. Thus the rdgC+ gene product is required to prevent retinal degeneration that results from a previously unrecognized consequence of rhodopsin stimulation.
Asunto(s)
Drosophila/genética , Mutación , Células Fotorreceptoras/fisiología , Degeneración Retiniana , Pigmentos Retinianos/fisiología , Rodopsina/fisiología , Envejecimiento , Animales , Mapeo Cromosómico , Drosophila/fisiología , Electrofisiología/métodos , Luz , Microscopía Electrónica , Fenotipo , Células Fotorreceptoras/crecimiento & desarrollo , Células Fotorreceptoras/ultraestructura , Fosfolipasas de Tipo C/metabolismoRESUMEN
There is a growing debate with regards to the appropriate methods of analysis of growth trajectories and their association with prospective dependent outcomes. Using the example of childhood growth and adult BP, we conducted an extensive simulation study to explore four two-stage and two joint modelling methods, and compared their bias and coverage in estimation of the (unconditional) association between birth length and later BP, and the association between growth rate and later BP (conditional on birth length). We show that the two-stage method of using multilevel models to estimate growth parameters and relating these to outcome gives unbiased estimates of the conditional associations between growth and outcome. Using simulations, we demonstrate that the simple methods resulted in bias in the presence of measurement error, as did the two-stage multilevel method when looking at the total (unconditional) association of birth length with outcome. The two joint modelling methods gave unbiased results, but using the re-inflated residuals led to undercoverage of the confidence intervals. We conclude that either joint modelling or the simpler two-stage multilevel approach can be used to estimate conditional associations between growth and later outcomes, but that only joint modelling is unbiased with nominal coverage for unconditional associations.
Asunto(s)
Presión Sanguínea , Desarrollo Infantil , Estudios Longitudinales , Estudios Prospectivos , Adulto , Sesgo , Tamaño Corporal , Niño , Preescolar , Intervalos de Confianza , Crecimiento , Humanos , Recién NacidoAsunto(s)
Síndrome de Inmunodeficiencia Adquirida/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/farmacología , Proteasa del VIH/efectos de los fármacos , VIH-1/enzimología , Aprobación de Drogas , Inhibidores de la Proteasa del VIH/uso terapéutico , VIH-1/efectos de los fármacos , Humanos , Indinavir , Isoquinolinas/farmacología , Isoquinolinas/uso terapéutico , Piridinas/química , Piridinas/farmacología , Piridinas/uso terapéutico , Quinolinas/farmacología , Quinolinas/uso terapéutico , Ritonavir , Saquinavir , Tiazoles/farmacología , Tiazoles/uso terapéutico , Estados Unidos , United States Food and Drug Administration , Valina/análogos & derivados , Valina/farmacología , Valina/uso terapéuticoAsunto(s)
Vacunas contra el SIDA , Síndrome de Inmunodeficiencia Adquirida/prevención & control , Proteína gp120 de Envoltorio del VIH/inmunología , Vacunas contra el SIDA/efectos adversos , Vacunas contra el SIDA/inmunología , Síndrome de Inmunodeficiencia Adquirida/epidemiología , Ensayos Clínicos Fase III como Asunto , Humanos , National Institutes of Health (U.S.) , Tailandia/epidemiología , Estados UnidosAsunto(s)
Síndrome de Inmunodeficiencia Adquirida/complicaciones , Caquexia/tratamiento farmacológico , Cannabis , Control de Medicamentos y Narcóticos , Caquexia/etiología , Protocolos Clínicos/normas , Política de Salud , Humanos , Fumar Marihuana , Estados Unidos , United States Food and Drug AdministrationAsunto(s)
Síndrome de Inmunodeficiencia Adquirida , Infecciones por VIH , VIH , Síndrome de Inmunodeficiencia Adquirida/prevención & control , Síndrome de Inmunodeficiencia Adquirida/terapia , Infecciones por VIH/prevención & control , Infecciones por VIH/terapia , Humanos , Política , Estados UnidosAsunto(s)
Síndrome de Inmunodeficiencia Adquirida/tratamiento farmacológico , Antivirales/provisión & distribución , Redes de Comunicación de Computadores , Servicios de Información sobre Medicamentos , Salud Global , Síndrome de Inmunodeficiencia Adquirida/economía , Antivirales/economía , Antivirales/uso terapéutico , Catálogos de Medicamentos como Asunto , HumanosAsunto(s)
Antivirales/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/uso terapéutico , Isoquinolinas/uso terapéutico , Quinolinas/uso terapéutico , Aprobación de Drogas , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Comercialización de los Servicios de Salud , Saquinavir , Estados Unidos , United States Food and Drug AdministrationAsunto(s)
Infecciones por VIH/tratamiento farmacológico , Antivirales/uso terapéutico , Recuento de Linfocito CD4 , VIH/aislamiento & purificación , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Inhibidores de la Proteasa del VIH/uso terapéutico , Humanos , Medicina , EspecializaciónAsunto(s)
Síndrome de Inmunodeficiencia Adquirida/fisiopatología , Hormona del Crecimiento/fisiología , Síndrome de Inmunodeficiencia Adquirida/tratamiento farmacológico , Hormona del Crecimiento/uso terapéutico , Hormona de Crecimiento Humana , Humanos , Proteínas Recombinantes/uso terapéutico , Pérdida de PesoRESUMEN
The quality of dehydrated taro slices in accelerated storage (45°C and 75% RH) was determined as a function of initial water activity (aw) and package type. Color, rehydration capacity, thiamin content, and α-tocopherol content were monitored during 34 weeks of storage in polyethylene and foil laminate packaging at initial storage aw of 0.35 to 0.71. Initial aw at or below 0.54 resulted in less browning and higher rehydration capacity, but not in significantly higher α-tocopherol retention. Foil laminate pouches resulted in a higher rehydration capacity and increased thiamin retention compared to polyethylene bags. Type of packaging had no effect on the color of the samples. Product stability was highest when stored in foil laminate pouches at 0.4aw. Sensory panels were held to determine the acceptability of rehydrated taro slices using samples representative of the taro used in the analytical tests. A hedonic test on rehydrated taro's acceptability was conducted in Fiji, with panelists rating the product an average of 7.2 ± 1.5 on a discrete 9-point scale. Using a modified Weibull analysis (with 50% probability of product failure), it was determined that the shelf life of dehydrated taro stored at 45°C was 38.3 weeks.