Fluorescence Values (fluorescence + value)

Distribution by Scientific Domains


Selected Abstracts


Comparison of two laser fluorescence devices for the detection of occlusal caries in vivo

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2007
Felix Krause
Laser fluorescence measurements have been shown to be well suited for caries diagnosis. The aim of this study was to compare two laser fluorescence devices and to correlate the respective values with the visual and radiographic assessment and with the extent of the carious lesion. Ninety-four clinically non-cavitated occlusal carious lesions in the premolars and molars of 82 patients were examined. Laser fluorescence values on the surface were measured with a conventional laser fluorescence system and a novel laser fluorescence pen device. When operative intervention at a site was indicated, the extent of caries was determined after its removal. Readings obtained with both systems were significantly different with an interdevice factor of 0.64. Sensitivity and specificity for operative care were 92.6% and 53.7%, respectively, for the conventional, and 88.9% and 53.7%, respectively, for the pen device. For both devices, a correlation between laser fluorescence values and the visual and radiographic assessment and with the extent of the lesion was shown. The study indicates that the novel laser fluorescence device seems to be suitable for occlusal caries diagnosis. However, proposed guidelines for the clinical use of laser fluorescence readings of the conventional device cannot be transferred to the novel pen system. [source]


An in vitro study of the reliability of DIAGNOdent® measurements

JOURNAL OF ORAL REHABILITATION, Issue 9 2004
J Kühnisch
summary, Aim of this in vitro study was to assess the reliability of measurements by a laser fluorescence technique for occlusal caries detection. Four dentists using four DIAGNOdent® devices (Dds) according to manufacturer's instructions examined 80 carefully cleaned extracted molars with non-cavitated occlusal lesions. Inter- and intra-examiner reproducibility were calculated using Lin's intra-class correlation coefficient (ICCLin) and the limits of agreement by Bland and Altman (Comp Biol Med 1990;20:337). An excellent intra-examiner reproducibility was found for all dentists (ICCLin 0·93,0·98). The inter-examiner reliability was proved to be good and excellent (ICCLin 0·74,0·98). By reason of the registered lower mean fluorescence values of dentist 3 compared with his/her colleagues all these measurements were excluded from further calculations. Differences between Dd instruments were not evident. When the values of the Dd were categorized according to the treatment related cut-off limits a substantial reproducibility was found in the range of 0,14 (ICCLin 0·66; DIFF 4·0/,3·5) and >30 (ICCLin 0·6% of all Dd measurements were reproduced in the range 15,30 (ICCLin 0·16; DIFF 8·1/,7·3). The results suggest that dentists should be trained before using Dd. The low reliability in the interval of 15-30 could indicate a limited use for a longitudinal caries monitoring on pits and fissures; further research should be focused on this clinically important interval. [source]


Chemistry and genotoxicity of caramelized sucrose

MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 12 2006
David D. Kitts
Abstract Caramelization of a 1% sucrose solution at 180°C accompanied characteristic changes in pH, Mr, UV-absorbance, and fluorescence values as well as increased reducing power activity after 40,60 min. Similar changes occurred to sucrose heated at 150°C, after 150,240 min. Bioactivity of caramelized sucrose samples was tested for mutagenic activity, using Salmonella typhimurium strains TA-98 and TA-100, respectively, as well as the Saccharomyces D7 yeast strain for mitotic recombination and Chinese hamster ovary cells (CHO) to assess clastogenicity. Caramelized sucrose expressed no mutagenicity in the TA-98 strain, but gave positive (p < 0.05) results with the TA-100, base-pair substitution strain. Similarly, mitotic recombination in the Saccharomyces D7 yeast strain and clastogenic activity in CHO cells were induced when exposed to caramelized sucrose. In the all cases, preincubation with S-9 reduced (p < 0.05) the mutagenic activities of caramelized sucrose. Fractionation of the caramelized sucrose into volatile and nonvolatile compounds was performed and tested for clastogenicity using CHO cells. Volatile components contributed approximately 10% to total clastogenicity, which was enhanced by the presence of S-9. Nonvolatile components recovered, consisting of relatively lower Mr, gave highest (p < 0.05) clastogenic activity, denoting that higher Mr caramel colors are relatively free of this property. [source]


Real-time measurement of nitric oxide in single mature mouse skeletal muscle fibres during contractions

THE JOURNAL OF PHYSIOLOGY, Issue 1 2007
Deborah Pye
Nitric oxide (NO) is thought to play multiple roles in skeletal muscle including regulation of some adaptations to contractile activity, but appropriate methods for the analysis of intracellular NO activity are lacking. In this study we have examined the intracellular generation of NO in isolated single mature mouse skeletal muscle fibres at rest and following a period of contractile activity. Muscle fibres were isolated from the flexor digitorum brevis muscle of mice and intracellular NO production was visualized in real-time using the fluorescent NO probe 4-amino-5-methylamino-2,,7,-difluorofluorescein diacetate (DAF-FM DA). Some leakage of DAF-FM was apparent from fibres loaded with the probe, but they retained sufficient probe to respond to changes in intracellular NO following addition of the NO donor 3-(2-hydroxy-1-methyl-2-nitrosohydrazino)- N -methyl-1-propanamine (NOC-7) up to 30 min after loading. Electrically stimulated contractions in isolated fibres increased the rate of change in DAF-FM fluorescence by ,48% compared to non-stimulated fibres (P < 0.05) and the rate of change in DAF-FM fluorescence in the stimulated fibres returned to control values by 5 min after contractions. Treatment of isolated fibres with the NO synthase inhibitors NG -nitro- l -arginine methyl ester hydrochloride (l -NAME) or NG -monomethyl- l -arginine (l -NMMA) reduced the increase in DAF-FM fluorescence observed in response to contractions of untreated fibres. Treatment of fibres with the cell-permeable superoxide scavenger 4,5-dihydroxy-1,3-benzenedisulphonic acid (Tiron) also reduced the increase in fluorescence observed during contractions suggesting that superoxide, or more probably peroxynitrite, contributes to the fluorescence observed. Thus this technique can be used to examine NO generation in quiescent and contracting skeletal muscle fibres in real time, although peroxynitrite and other reactive nitrogen species may potentially contribute to the fluorescence values observed. [source]


Facial skin fluorescence as a marker of the skin's response to chronic environmental insults and its dependence on age

BRITISH JOURNAL OF DERMATOLOGY, Issue 1 2006
G.N. Stamatas
Summary Background, Throughout life facial skin is exposed to a variety of adverse environmental conditions and is constantly required to repair itself. The rate of epidermal cell proliferation is indicative of the skin's repair rate and can be monitored noninvasively in vivo using skin intrinsic fluorescence markers. Objectives, The goal of the present study was to assess the effects of ageing, geographical region, ethnic origin and season on the ability of facial skin to repair itself in the presence of chronic environmental insults using in vivo fluorescence spectroscopy. Methods, Skin fluorescence emission was measured on the cheeks of 522 individuals in winter and repeated in summer in five different geographical locations in the Asia-Pacific region. Fluorescence emission was also measured from 80 caucasians of fair complexion in the United States (New Jersey area) on the face and on a relatively protected area (upper inner arm). The age range of the participants was 14,75 years. Results, We found that epidermal proliferation rates decrease monotonically with age, while the fluorescence of collagen and elastin cross-links increases with age indicating accumulation of advanced glycation end-products. These trends were independent of geographical region, ethnic origin and season of measurement. Epidermal proliferation rates of facial skin were higher than those of unexposed sites; they may be 10 times higher in younger (second decade) than in older (seventh decade) individuals, and they decrease with age at rates 10 times faster compared with those of unexposed sites. Conclusions, This is the first time that epidermal proliferation and its dependence on ageing have been measured noninvasively on the human face. The higher tryptophan fluorescence values on the face vs. the protected site are indicative of accelerated rates of epidermal proliferation in the presence of chronic environmental insults. The repair potential of facial skin, i.e. its ability to maintain high proliferation rates, is maximal in younger populations and gradually decreases with age. [source]