RESUMO
Over the past two decades there have been significant advances in our understanding of both the anatomy and function of the melanopsin system. It has become clear that rather than acting as a simple irradiance detector the melanopsin system is in fact far more complicated. The range of behavioural systems known to be influenced by melanopsin activity is increasing with time, and it is now clear that melanopsin contributes not only to multiple non-image forming systems but also has a role in visual pathways. How melanopsin is capable of driving so many different behaviours is unclear, but recent evidence suggests that the answer may lie in the diversity of melanopsin light responses and the functional specialisation of photosensitive retinal ganglion cell (pRGC) subtypes. In this review, we shall overview the current understanding of the melanopsin system, and evaluate the evidence for the hypothesis that individual pRGC subtypes not only perform specific roles, but are functionally specialised to do so. We conclude that while, currently, the available data somewhat support this hypothesis, we currently lack the necessary detail to fully understand how the functional diversity of pRGC subtypes correlates with different behavioural responses, and ultimately why such complexity is required within the melanopsin system. What we are lacking is a cohesive understanding of how light responses differ between the pRGC subtypes (based not only on anatomical classification but also based on their site of innervation); how these diverse light responses are generated, and most importantly how these responses relate to the physiological functions they underpin.
Assuntos
Células Ganglionares da Retina/fisiologia , Opsinas de Bastonetes/fisiologia , Visão Ocular/fisiologia , Vias Visuais/fisiologia , Animais , Humanos , Luz , Células Ganglionares da Retina/classificação , Células Ganglionares da Retina/efeitos da radiaçãoRESUMO
The current study reports the preparation and stabilization of novel functional drinks based on fruit and vegetable juices incorporating bacterial cellulose from Acetobacter xylinum. Pineapple, musk melon, carrot, tomato, beet root and a blend juice containing 20 % each of carrot and tomato juice with 60 % beet root juice has been studied. These juices have been stabilized over a storage period of 90 days at 28 °C, by the use of nisin and maintaining a low pH circumventing the need for any chemical preservatives or refrigeration. Instrumental color values have been correlated with the pigment concentrations present in the fresh as well as stored juices. There was 36, 72 and 60 % loss of total carotenoids in the case of carrot, pineapple and musk melon juices respectively while the lycopene content remained unchanged after 90 days of storage. The betanin content decreased 37 % in the case of beetroot juice and 25 % in the case of beetroot juice blended with carrot and tomato juices. Sensory analysis has revealed a clear preference for the beetroot blended mixed juice.
RESUMO
AIMS: The predicted survival of Bacillus subtilis 168 spores from a polynomial regression equation was validated in milk. METHODS AND RESULTS: Bias factor suggested as an index of model performance was used to validate the polynomial model predictions in ultrahigh temperature (UHT) treated and sterilized whole and skim milk. Model predictions were fail safe, predicting higher D-values (decimal reduction times) in buffer than actually noted in milk. CONCLUSIONS: The D-values for spores were lower in milk as compared with those predicted in potassium phosphate buffer contrary to the popular expectation of better spore survival in complex food systems. The Bias factor, a quantitative measure of the model performance, indicated that on average the model predictions exceed the observations by 40% in the case of whole milk and by 60% in the case of skim milk. SIGNIFICANCE AND IMPACT OF THE STUDY: The present work is an attempt to ascertain the extent of reliability that one can safely place in polynomial model predictions, without compromising on the safety or palatability of foods where it is eventually intended to be applied. The work has also highlighted the differences in the thermal inactivation pattern of spores in buffer and in milk with a possible influence of the various constituents of milk. The work will assist the dairy industry to better design thermal processes to ensure longer shelf life of dairy foods.
Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Temperatura Alta , Leite/microbiologia , Animais , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/fisiologia , Leite/química , Modelos Biológicos , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/fisiologiaRESUMO
AIMS: The inactivation of Bacillus subtilis 168 spores subjected to the combined stress of pH, temperature and sodium chloride in a buffer system was modelled. METHODS AND RESULTS: Bacillus subtilis 168 spore suspension in 50 mmol l-1 potassium phosphate buffer was heated in an open system using a block heater. A second order polynomial equation was used to describe the relationship between pH, temperature, sodium chloride concentration and the logarithm of the decimal reduction time (D-value) of the spores. Response surface graphs were constructed to predict the inactivation within the experimental domain. The data obtained were also compared with those reported for B. subtilis in different media and foods included in a large reference-based database of thermal inactivation (ThermoKill Database, TKDB R9100), which was constructed in the laboratory. CONCLUSIONS: All the variables studied seemed to have a significant effect on the inactivation of B. subtilis 168 spores in potassium phosphate buffer. The coefficient of determination, r2, and an analysis of the residuals from the model indicated the adequacy of the model to predict the inactivation of B. subtilis spores within the range of the experimental variables studied. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of this study will enable a better understanding of the inactivation of B. subtilis spores under the influence of the studied environmental variables. The model can be used by food industries to assess and monitor the shelf life of food products in the event of a chance contamination by B. subtilis spores.
Assuntos
Bacillus subtilis/fisiologia , Manteiga/microbiologia , Microbiologia de Alimentos , Bacillus subtilis/efeitos dos fármacos , Temperatura Alta , Concentração de Íons de Hidrogênio , Matemática , Modelos Biológicos , Cloreto de Sódio/farmacologia , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/fisiologiaRESUMO
The increasing popularity of traditional milk-based foods has placed emphasis on the need for microbial safety in food-chain establishments, as there are ample possibilities for foodborne pathogens to occur as postprocessing contaminants. The behavioral pattern of an enterotoxigenic strain of Escherichia coli D 21 introduced as a postprocessing contaminant in shrikhand, a traditional sweetened lactic fermented milk product, was studied with variables of initial inoculum (4.3, 5.3, and 6.3 log10 CFU/g), storage temperature (4, 10, and 16 degrees C), and storage period (4, 9, and 14 days). During storage of shrikhand prepared individually with Lactobacillus delbruecki ssp. bulgaricus CFR 2028 and Lactococcus lactis ssp. cremoris B-634, there was a steady decrease in the viable count of E. coli that was proportional to the initial inoculum of E. coli introduced into shrikhand. The data were subjected to multivariate analysis, and equations were derived to predict the behavior of E. coli in shrikhand. The predicted values for the probable survival of E. coli showed good agreement with the experimental values with a majority of these predictions being fail-safe. The values of statistical indices showed that the model fits ranged between extremely good and satisfactory. Response surface plots were generated to describe the behavioral pattern of E. coli. The derived models and response surface plots enabled prediction of the survival of E. coli in shrikhand as a function of initial inoculum levels, storage temperatures, and storage periods of shrikhand. These predictions were valid within the limits of the experimental variables used to develop the model.
Assuntos
Escherichia coli/fisiologia , Contaminação de Alimentos , Leite/microbiologia , Animais , Contagem de Colônia Microbiana , Escherichia coli/crescimento & desenvolvimento , Fermentação , Ácido Láctico , Modelos Biológicos , Modelos Estatísticos , Temperatura , Fatores de TempoRESUMO
Three newborn infants with flank masses underwent magnetic resonance (MR) imaging after ultrasound (US) indicated adrenal hemorrhage and/or renal vein and inferior vena cava thrombosis. MR imaging was valuable in defining the hemorrhagic nature of echogenic and hypoechoic suprarenal masses and in delineating thrombi within the renal veins and inferior vena cava. Two infants with renal parenchymal damage had abnormal radionuclide scans and abnormal corticomedullary distinction on MR images. The major role of MR imaging may be in the early course of these conditions, when added diagnostic specificity is likely to affect patient management. In most instances, size of hemorrhage and intravenous clots, as well as renal size, may be accurately followed with US, while radionuclide scanning remains necessary for evaluation of renal functional impairment.
Assuntos
Doenças das Glândulas Suprarrenais/diagnóstico , Hemorragia/diagnóstico , Imageamento por Ressonância Magnética , Veias Renais , Trombose/diagnóstico , Doenças das Glândulas Suprarrenais/complicações , Glândulas Suprarrenais/patologia , Hemorragia/complicações , Humanos , Recém-Nascido , Masculino , Veias Renais/patologia , Trombose/complicações , Veias Cavas/patologiaRESUMO
Findings on plain chest radiographs of patients with aortic dissection are variable and often overlap those of patients without dissection. To determine which findings were most useful in predicting aortic dissection, plain chest radiographs from 36 patients with aortographically proven aortic dissection and 36 patients from a control population were randomized and analyzed independently by five radiologists for the presence of various radiographic features associated with this condition. A widened aortic knob, widened descending aorta, and widened mediastinum showed the greatest interobserver agreement (p less than .001) although the overall interobserver agreement was poor. The final conclusion of the radiologists was a better predictor of dissection than any of the individual radiographic features alone. Widening of the mediastinum (p less than .001) and widening of the aortic knob (p less than .012) were the only two radiographic features of significance in predicting dissection. In a stepwise multiple logistic regression model, the radiologists achieved an overall accuracy of 85%, a sensitivity of 81%, and a specificity of 89%. Although this illustrates the usefulness of plain chest radiographs in diagnosing aortic dissection, poor interobserver agreement dictates that further definitive investigation be undertaken.
Assuntos
Aneurisma Aórtico/diagnóstico por imagem , Dissecção Aórtica/diagnóstico por imagem , Estatística como Assunto , Adolescente , Adulto , Idoso , Aortografia , Feminino , Humanos , Masculino , Mediastino/diagnóstico por imagem , Pessoa de Meia-Idade , Radiografia Torácica , SoftwareRESUMO
An unusual case of hemopericardium and presumed fatal cardiac tamponade complicating attempted right internal jugular vein catheterization by the posterior approach is reported. Reports of complications in a series of internal jugular vein catheterizations using various approaches (posterior, central, anterior, supraclavicular) and subclavian vein catheterizations are reviewed. Internal jugular vein catheterization is not necessarily safer than subclavian vein catheterization: numerous factors determine success rate and complication rate in central venous catheterizations.
Assuntos
Cateterismo/efeitos adversos , Veias Jugulares , Derrame Pericárdico/etiologia , Idoso , Tamponamento Cardíaco/etiologia , Cateterismo/métodos , Feminino , Humanos , Veia SubcláviaRESUMO
A 13-year-old girl developed Addison's disease during antituberculous therapy for presumed tuberculous ventriculitis. CT of the abdomen showed diffusely enlarged hypodense adrenals and a hypodense lesion in the lower pole of the left kidney. Biopsy of the renal lesion revealed caseating and noncaseating granulomas.
Assuntos
Doença de Addison/diagnóstico , Tuberculose Endócrina/diagnóstico , Adolescente , Feminino , HumanosRESUMO
Biochemical and histochemical studies have indicated that there is specific cellular activity in the region of the calcification front of articular cartilage implying that a regulation process takes place there. Using scanning and transmission electron microscopy and light microscopy to examine tissue sections of both undecalcified and decalcified articular cartilage in the region of the calcification front, we have looked at its morphology with particular reference to its cellular control. Our observations show that physiological calcification is an active process under cellular control and is related to the presence of extracellular membrane-bound matrix vesicles.
Assuntos
Calcificação Fisiológica , Cartilagem Articular/fisiologia , Animais , Matriz Óssea/ultraestrutura , Cartilagem Articular/ultraestrutura , Cães , Técnicas Histológicas , Microscopia Eletrônica/métodos , Microscopia Eletrônica de VarreduraRESUMO
The high-affinity antagonist, 3-quinuclidinyl benzilidate (QNB), was used to analyze muscarinic-cholinergic receptor activity in the optic tectum of goldfish and optic lobe of developing chicks and adult pigeons after deafferentation. After deafferentation no significant loss of total or specific muscarinic receptor binding activity was observed in contrast to prior experiments where there was a marked and rapid loss of nictonic-cholinergic receptor binding activity, as measured by alphabungarotoxin binding. The relative stability of the muscarinic site as opposed to the instability of the nicotinic site in these experiments is discussed.