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PubMed1990

Colorimetric quantification of erythema--a comparison of two colorimeters (Lange Micro Color and Minolta Chroma Meter CR-200) with a clinical scoring scheme and laser-Doppler flowmetry.

Erythema elicited by the local irritant sodium lauryl sulphate was studied in comparison with unexposed skin. Colour coordinates of the CIE system were recorded using two commercially available colorimeters. With both colorimeters a positive movement of the alpha-axis (toward red, P less than 0.001) and a negative movement on the L-axis (toward dark, P less than 0.01) were registered. Technical and in-vivo experimentation showed the two pieces of equipment to be accurate. However, a simple conversion factor cannot be established. Both pieces of equipment correlated positively with clinical scoring of erythema and with measurement of cutaneous blood flow by laser-Doppler flowmetry. In conclusion, the two colorimeters appeared comparable. Colorimetry by the CIE system, which takes into account the non-linear colour perception of the human eye, was found useful with potential value in both experimental and clinical dermatology. The techniques appeared suitable for routine testing.

Adolescent↗

PubMed1977

A colorimetric study of coffee and tea staining of four composite resins.

Colorimetric measurements were made on four composite resins before and after controlled immersion treatments. The four composite resins were: Adaptic (Johnson and Johnson), Prestige (Lee Pharmaceuticals), Addent XV (3M Mfg. Co.) and Smile (Kerr Mfg. Co.). Specimens of each material were prepared with mylar surfaces and with abraded finished surfaces. Separate groups of specimens of the four materials were immersed in three separate solutions for 12 days at 55c. The three solutions used were: a control solution of distilled water and coffee and a solution of distilled water and tea. For all materials and surface finishes, immersion in coffee and tea produced significantly greater colour changes than distilled water. Coffee produced significantly greater colour changes than tea with the exception of 'Prestige' and 'Addent XV' with finished surfaces. When immersed in a tea solution, specimens of the same material with differing surface finishes showed greater differences in colour change than when immersed in control and coffee solutions. The relative colour changes of the four materials due to the immersion procedures were as follows: 'Adaptic' showed the least colour changes and "Smile' showed the most. 'Addent XV' and 'Prestige' tended to vary between the former two. Comparison and correlation of colorimetry results with visual assessment scores allowed for the expression of the objective measures in subjective terms suitable for clinical purposes.

Coffee↗

PubMed1994

Effects of softened and unsoftened fabrics on sensitive skin.

The effects of softened fabrics on the skin were evaluated by a forearm wet and dry test, under conditions simulating real-life skin contact with fabrics. 15 volunteers with sensitive skin according to dermatological assessment and their own recognition entered a double-blind 12 day, 3 sessions per day, forearm wetting and drying test, using cotton fabrics washed with a powder detergent and softened or not with a liquid fabric conditioner. To simulate conditions of skin damage, a dilute solution of sodium lauryl sulfate was applied under patch to the forearm before the start of the study. Skin effects were evaluated by visual grading (redness, dryness and smoothness), by noninvasive skin stripping and measuring of Chroma C* (squamometry), and by instrumental measurements (capacitance, transepidermal water loss, and colorimetry). Both the unsoftened and softened fabrics induced no deleterious effects on control or previously irritated skin. Furthermore, a mild beneficial effect was observed with the softened fabrics, particularly on previously irritated skin. The study findings suggest that softened fabrics may exert a reduced frictional effect on the skin.

Adult↗

PubMed1996

Ultrasound description and quantification of irritant reactions induced by dithranol at different concentrations. A comparison with visual assessment and colorimetric measurements.

Dithranol (D) is used as a therapeutic topical agent to treat psoriasis, although it produces inflammation and staining of skin and clothing. D-induced irritation has been evaluated by visual scoring and by bioengineering techniques, evidencing modifications of the inflammatory parameters, but no alterations of the skin barrier. The aim of our study was to evaluate the irritant reactions induced by D using ultrasound, and to compare the B-scanning data with visual assessments and colorimetric measurements. 13 healthy women underwent 2, 3-h patch tests with, respectively, 0.02% and 0.1% D in white petrolatum and 1 24-h patch test with 2% sodium lauryl sulfate (SLS). For assessing skin reactions, clinical judgement, colorimetry and echography were employed. Echographic images were evaluated by skin thickness measurements and segmentation procedures, using an 0-30 interval, marking the hyporeflecting areas in the dermis, and a 201-255 interval, assessing the hyperreflecting components of the image (both epidermal and dermal). In all subjects, D produced uniform reactions, the intensity varying according to concentration. Both echographic parameters of inflammation (skin thickness and 0-30 areas) showed an increase at all times of assessment. The 201-255D/0-30 pixel ratio, describing the distribution of dermal edema, indicated that strong inflammatory reactions, such as those caused by the application of 0.1% D, are accompanied by edema in the lower portion of the dermis. Finally, in contrast to SLS reactions, where a 24-h reduction in epidermal reflectivity was observable, D reactions appeared with an accentuation of the 201-255 epidermal band at 24-96-h examinations.

Administration, Topical↗

PubMed1996

Efficacy of 4 commercially available protective creams in the repetitive irritation test (RIT).

Protective creams (PCs) play their part in the prevention of occupational contact dermatitis, even though efficacy data are frequently lacking. 4 different commercially-available PCs were evaluated against a set of 4 standard irritants (10% sodium lauryl sulfate (SLS), 1% sodium hydroxide (NaOH), 30% lactic acid (LA) and undiluted toluene (TOL)) in the repetitive irritation test (RIT) in humans described by Frosch and Kurte. 20 subjects were tested on the paravertebral skin on the mid-back. Irritation was assessed by visual scoring, transepidermal water loss (TEWL) as an indicator of epidermal barrier function, and colorimetry as a parameter of inflammation. Very different protective effects of the PCs on irritation by chemical substances were detectable. All products were very effective against SLS irritation. No PC provided significant protection against toluene. 3 products showed a partially protective effect against all ionic irritants, while the 4th showed less protection against SLS and NaOH, and even amplification of inflammation by TOL. Considering the range of PC effects from good protection to increased irritation, depending on the irritant, the need for careful selection of PCs for specific workplaces is stressed.

Administration, Topical↗

PubMed1996

Guidelines for measurement of skin colour and erythema. A report from the Standardization Group of the European Society of Contact Dermatitis.

This report reviews individual-related variables (age, sex, race, anatomical site, skin surface properties), intra- and interindividual variation (temporal, physical and mental activity, orthostatic effect, menstrual cycle/menopause), environment-related variables (light conditions, temperature) and various instrument-related variables that influence skin colour. CIE colorimetry (Minolta Chroma Meter) and spectrophotometric measurement (Derma Spectrometer) are considered. The guidelines give recommendations for measuring conditions and procedures.

Adult↗

PubMed1996

Sodium lauryl sulfate (SLS) induced irritant contact dermatitis: a correlation study between ceramides and in vivo parameters of irritation.

Sodium lauryl sulfate (SLS), a surfactant frequently used in the induction of experimental irritant contact dermatitis in animals and in humans, characteristically induces a dose-related increase in TEWL (transepidermal water loss). Ceramides are considered to be important in the regulation of the skin barrier. We therefore examined the relationship between initial ceramide content of stratum corneum and induced changes in skin color (erythema) and barrier function, after SLS application under occlusion (1% and 3% in water) to the forearm of 14 volunteers. Stratum corneum sheets were removed, stratum corneum lipids extracted, and ceramide composition determined from chromatograms (TLC) using densitometry. After determining baseline skin color and TEWL at each area, 2 samples of stratum corneum were obtained from each volunteer. Clinical and instrumental controls of the SLS-induced irritation were performed at 24, 48, 72 and 96 h. Erythema was evaluated by colorimetry: barrier impairment by changes in TEWL. We found inverse correlations between baseline ceramide 61 (weight) and the 24 h erythema score for SLS 3%, between ceramide 1 and 24 h TEWL, and between ceramide 611 and 72 h TEWL for SLS 3%. Our findings suggest that low levels of these ceramides may determine a proclivity to SLS-induced irritant contact dermatitis.

Adult↗

PubMed1996

Effect of barrier creams: human skin in vivo.

An in vivo method was developed to measure the effectiveness of skin protective creams against 2 dye indicator solutions: methylene blue in water and oil red O in ethanol, representative of model hydrophilic and lipophilic compounds. 3 representative barrier creams commercialized as effective against lipophilic, hydrophilic, or lipophilic and hydrophilic substances were assayed by measurements of the dye in cyanoacrylate strips of protected skin samples after various application times. The flexural surfaces of the forearms of 6 normal volunteers (3 female and 3 male, mean age 26.8 +/- 4.1 years) were treated. The method was as follows: solutions of 5% methylene blue in water and 5% oil red O in ethanol were prepared, and applied to untreated skin and protective-cream-pretreated skin with the aid of aluminum occlusive chambers, for 0 h and 4 h, respectively. At the end of the application time, the creams were removed. Consecutive skin surface biopsies (SSB) from 1 to 4 strips were taken. The amount of stain in each strip was determined by colorimetry, and the cumulative amount of stain from 1 to 4 strips in each measurement was calculated. The cumulative amount represents the amount of permeation of each solution at each time point, and the efficacy of skin barrier cream. The results showed one formulation at both 0 h and 4 h reduced the amount of permeation of methylene blue (p < 0.01) and oil red O (p < 0.01) compared with the control group. Another formulation was protective against the permeation of oil red O (p < 0.01), but not against methylene blue at 0 h and 4 h; it was not significantly different at 0 h versus 4 h. The 3rd formulation produced increased cumulative amounts to oil red O at both 0 h and 4 h (p < 0.05); it also increased permeation amounts to methylene blue (p < 0.05) after 4 h. This model appears a facile, rapid and objective early screen to evaluate the efficacy of skin barrier creams in vivo, as well as their individual ingredients.

Adult↗

PubMed1982

Effect of cadmium on calcium, magnesium and phosphorus content of rat molars.

Eleven groups of Wistar rats, 10 animals in each group, received graded doses of CdCl2 in the drinking water from conception until sacrifice at the age of 10 weeks. The Ca and Mg contents of whole molars as well as enamel and dentin for each group were recorded by atomic absorption spectrophotometry (AAS). The inorganic P content of the control and three experimental groups was measured by colorimetry. Four molars from each of eight additional animals, four controls and four from the 22.5 parts/10(6) Cd group were ground transversely and subjected to X-ray microanalysis. AAS analyses showed that the Ca level of whole molars increased significantly with a Cd supply above 2.5 parts/10(6). The Ca content was significantly correlated with the Cd contents of the same teeth. The increased Ca seemed to be in the enamel. The Mg content decreased significantly with Cd doses below 12.5 parts/10(6). This decrease seemed to be in dentin. The P level of the molars increased following Cd supply, but not significantly so. The X-ray spectra demonstrated that there were no significant differences between the Ca/P ratios of the two groups, either in enamel or in dentin. It is concluded that absorption of Cd alters the normal Ca, Mg and P levels in rat molars. This may reflect a disturbance of Ca, P and Mg metabolism in the organism generally.

Animals↗

PubMed2005

Influence of smoking on metallothionein level and other proteins binding essential metals in human milk.

AIM: To assess the influence of smoking on the level of total protein, metallothionein (MT), albumin and lactoferrin in human breast milk. METHODS: Samples of whole milk and supernatants of milk after centrifugation at 10 000 x g and 105 000 x g were analysed. Cadmium was determined by graphite furnace atomic absorption spectrometry (GFAAS). The concentration measurements employed the following methods: total protein by Lowry, albumin by colorimetry, cotinine and lactoferrin by ELISA tests, metallothionein by 109Cd/haemoglobin assay. RESULTS: The assessment of tobacco smoke exposure was based on concentrations of cotinine in breast milk (197 +/- 98 ng/ml in smokers and 23 +/- 11 ng/ml in non-smokers; p < or = 0.001) and serum (179 +/- 87 ng/ml and 32 +/- 19 ng/ml, respectively; p < or = 0.001). The level of cadmium was four times higher in the milk of smoking women than in non-smokers. The concentration of total protein was lower in smoking (37.3 +/- 10.6 mg/ml) than in non-smoking mothers (51.8 +/- 13.8 mg/ml; p < or = 0.02). No significant differences between albumin and lactoferrin concentrations were observed. The level of metallothionein was over twice as low in smokers (5.1 +/- 1.9 microg/ml) than in non-smokers (13.4 +/- 3.0 microg/ml; p < or = 0.001), and an inverse correlation between MT level and cadmium concentration (r = -0.86; p = 0.001) was noticed. CONCLUSIONS: The breast milk of smoking mothers might be of lower nutritive value. The amount of MT transported by milk to the mammary gland is smaller in smokers than in non-smokers, which may prove to be advantageous to an infant because of the higher toxicity of the Cd-MT complex than that of inorganic Cd salts.

Adult↗

PubMed1992

Indirect spectral transmission ratio measurements of the aging crystalline lens nucleus.

A new objective approach to characterize color and opalescence in the lens nucleus, using wavelength indexed transmission ratios (TR) is described. Transmission ratios, i.e. the transmissivity per unit lens thickness, for the whole visible spectral range (390-720 nm) were calculated using fast scanning spectral colorimetry (FSSC). The lowest transmission ratios values were obtained in the blue part of the spectrum in general and at 450 nm in particular. They inversely followed the subjectively determined LOCS II color grading. The difference between transmission ratios at the absorbed part of the spectrum (less than 500 nm) and the non-absorbed part (greater than 550 nm) also reflects the LOCS II color grading. The overall mean transmission ratios for all wavelengths in the spectrum gives an index that closely followed the nuclear opalescence grading of the LOCS II system. The transmission ratios are theoretically independent of the spectral characteristics of the incident light as long as it contains suprathreshold energies in the whole measured spectral range.

Absorption↗

PubMed2004

The practical application of reflectance spectrophotometry for the demonstration of haemoglobin and its degradation in bruises.

AIMS: To develop a non-invasive method to demonstrate the presence of haemoglobin and its degradation products in bruises in live human subjects for the purposes of objectively assisting in the determination of the age of a bruise. METHODS: The cuvette holder unit of a Cary 100 Bio UV-Visible Spectrophotometer was replaced with the manufacture's fibre optic cable and optical reflectance probe. The probe was placed on the skin surface. The absorption spectrum from 780 to 380 nm was collected and transformed into the first derivative. Calculation of the first derivative permits absorption attributed to haemoglobin degradation (primarily to bilirubin, but also haemosiderin) to be separated from absorption by haemoglobin. First derivative and colorimetry values, expressed as CIEL*a*b data, were derived from scans of 50 bruises. RESULTS: The fibre optic cable and probe allowed the spectrophotometer to collect reproducible absorption spectra of bruises in the skin of living subjects. A bruise at three days has greater negative first derivative values at 480 and 490 nm than does a fresh bruise, indicating the local degradation of haemoglobin. Correlation between the first derivative and the CIEL*a*b "b" values in a series of bruises indicates that the yellow colour in a bruise is proportional to the amount of local haemoglobin breakdown. CONCLUSION: The ability to demonstrate the presence of haemoglobin and measure its degradation in bruises in living human subjects by a non-invasive method has not been described previously, and may be of use in the objective ageing of bruises for forensic purposes.

Bilirubin↗

PubMed1970

An evaluation of the automated assay of urinary oestrogens in pregnant women.

An automated assay suitable for estimating urinary oestrogens in pregnant women has been investigated. Fluorimetry was found to have considerable advantages over colorimetry. The fluorimetric assay was simpler, more precise, more sensitive, and eliminated the need for correction for non-specific chromogens; in the assay of oestriol in pregnant women there was no need for correction for non-specific fluorescence. Spectrofluorimetric and photometric analyses, recoveries, and reproducibility show that the method offers a robust means of providing values for urinary oestrogen in pregnant women on a scale of up to 100 tests a day, the time of the assay being one and a half hours.

Autoanalysis↗

PubMedDate not supplied

Predicting visual assessment of allergic patch test reactions by non-invasive measurements.

The quantification of allergic patch test reactions to several compounds was evaluated on patients using laser Doppler velocimetry (LDV), transepidermal water loss and colorimetry. The correlation between visual scores and instrumental measurements was investigated by the implementation of a modern statistical method: a classification tree. The LDV showed the highest correlation with the severity of the reaction. The best prediction model was obtained when the data of the three instruments were considered together. Using the classification tree methodology, a model of classification, independent of human observation, was developed. The technique can not only predict an allergic reaction for a new patient, but can also give a measure of how reliable its predictions are. This new method, when entirely standardised and approved, could help in the harmonisation of patch test reactions in different laboratories, thus allowing a more homogenous interpretation of these reactions.

Adult↗

PubMed1988

New aspects on the metabolism of the sennosides.

Pure sennoside B was administered to rats. On appearance of the first wet faeces, sennoside B and its metabolites were determined in different parts of the alimentary tract, in faeces and in the urine. The total recovery of unchanged sennoside B and its metabolites was determined by alkali fusion followed by colorimetry and high-pressure liquid chromatography (HPLC). Alkali fusion in 1 N sodium hydroxide solution formed red solutions with sennosides and sennoside derivatives. The molar absorbance of sennosides A and B, sennidin B monoglucoside, sennidins, rhein, danthron, dithranol, rhein-8-glucoside and rhein anthrone at wavelengths of 505-530 nm related approximately to the number of ionizable hydroxy groups in the molecule. Brown polymerized products were isolated from the senna drug. The colour intensity of these products was approximately the same by weight as that of the sennosides themselves, although sennidins could no longer be freed from these by acid hydrolysis. After administration of sennoside B, the average sum of unchanged glucoside and known metabolites in different parts of the gastrointestinal tract and faeces of rats was 61.6% according to HPLC and 92.8% according to the alkali fusion procedure. This difference is indicative of the presence of substances which are no longer identifiable as sennoside derivatives, either by HPLC or by other classical chromatographic methods. Sennosides seem to be partly present in the alimentary tract in polymerized or bound form. The alkali fusion method may be useful in connection with the isolation of as yet unknown metabolites of the sennosides in the gastrointestinal tract.

Alkalies↗

PubMed1993

Kinetics of sebum excretion evaluated by the Sebutape--Chromameter technique.

We present a novel method for studying the changing characteristics of sebum excretion of facial skin over a 3-hour period. Sebum production can be quantified by analysis of the pore patterns formed on a sebum-sensitive tape (Sebutape). We applied the CIE principles of reflectance colorimetry by measuring L*, a* and b* of Sebutapes every 15 min during 3 h of sebum collection. This combined technique yielded valuable new informations on the kinetics of sebum excretion, allowing the distinction between the follicular reservoir effect and the sebum flow.

Adult↗

PubMed1997

Effect of organic solvents on normal human stratum corneum: evaluation by the corneoxenometry bioassay.

BACKGROUND: Organic solvents alter the stratum corneum structure and barrier function. OBJECTIVE: To measure the effect of various solvents upon human stratum corneum using the ex vivo corneoxenometry bioassay which is a variant of corneosurfametry. METHODS: Corneoxenometry entails collection of human stratum corneum by cyanoacrylate. The material is immersed in organic solvents for periods ranging from 1 to 120 min. After staining the samples with a toluidine blue-basic fuchsin solution, the color is measured using reflectance colorimetry. Solvent aggressivity to the stratum corneum correlates with the color darkening of the samples. RESULTS: The least aggressive solvent was hexane, followed by ethanol, methanol, hexane-ethanol, chloroform, chloroform-methanol and hexane-methanol. The influence of contact time between solvents and the stratum corneum showed a logarithmic pattern which varied according to the solvent. CONCLUSION: Data are in line with previous experiments conducted in vivo and in vitro, thus indicating the predictive value of corneoxenometry. Such a bioassay may avoid hazards of some in vivo human testings.

Alcohols↗

PubMed1997

Petrolatum prevents irritation in a human cumulative exposure model in vivo.

BACKGROUND: Protective creams (PCs) have been studied in different models indicating a protective effect of some products. In order to compare PCs in different studies, a generic reference standard should be available. OBJECTIVE: The purpose of this study was to investigate if petrolatum prevents epidermal barrier disruption induced by various irritants in a repetitive irritation test (RIT) and to assess its potential as a standard reference product. METHODS: White petrolatum was evaluated against a set of 4 irritants [10% sodium lauryl sulphate (SLS), 1% sodium hydroxide (NaOH), 30% lactic acid (LA) and undiluted toluene (TOL)] in the RIT. Twenty subjects were tested on the paravertebral skin of the midback. Irritation was assessed by visual scoring, transepidermal water loss and colorimetry. RESULTS: Petrolatum was very effective against SLS, NaOH and LA irritation, and it provided a moderate protection against TOL. CONCLUSION: Petrolatum can be recommended as a standard reference substance against which PCs may be compared as it is effective against water-soluble and water-insoluble irritants in a standardized test procedure.

Adolescent↗