Non-invasive identification of melanoma with near-infrared and skin impedance spectroscopy.

BACKGROUND/PURPOSE: An early diagnosis of cutaneous malignant melanoma is of high importance for good prognosis. An objective, non-invasive instrument could improve the diagnostic accuracy of melanoma and decrease unnecessary biopsies. The aim of this study was to investigate the use of Near-infrared and skin impedance spectroscopy in combination as a tool to distinguish between malignant and benign skin tumours. METHODS: Near-infrared and skin impedance spectra were collected in vivo on 50 naevi or suspect melanomas prior to excision. Received data were analysed using multivariate techniques and the results were compared to histopathology analyses of the tumours. A total of 12 cutaneous malignant melanomas, 19 dysplastic naevi and 19 benign naevi were included in the study. RESULTS: The observed sensitivity and specificity of the proposed method were 83% and 95%, respectively, for malignant melanoma. CONCLUSION: The results indicate that the combination of near-infrared and skin impedance spectroscopy is a promising tool for non-invasive diagnosis of suspect cutaneous malignant melanomas.

Improved ability to work after one year of natalizumab treatment in multiple sclerosis. Analysis of disease-specific and work-related factors that influence the effect of treatment.

BACKGROUND: Multiple sclerosis (MS) constitutes one of the major diseases that leads to neurological impairment and as a consequence also reduces ability to work. OBJECTIVES: The purpose of this study was to analyze possible effects on work ability resulting from highly active anti-inflammatory treatment in MS. METHODS: We analyzed the effects of introducing an anti-inflammatory treatment, natalizumab, in MS, on factors related to work ability. This was done through a comprehensive questionnaire distributed to all patients in Sweden starting on natalizumab treatment between June 2007 and May 2008, identified via the Swedish National MS registry. RESULTS: MS patients who were receiving sickness benefit and were treated with natalizumab approximately doubled their working ability in relation to their total employment rate. We also documented a significant improvement of their ability to cope with work-related requirements after one year of natalizumab treatment, an improvement which was independent of the previous level of employment. Predictors of a positive effect on work ability were short disease duration, younger age and lower Expanded Disability Status Scale (EDSS) grade at treatment onset. CONCLUSIONS: Our data support the notion that early inflammatory control in MS is essential to preserve a healthy state in MS that counteracts the negative consequences of the disease both at a personal and at a societal level.

NIR and skin impedance spectroscopic measurements for studying the effect of coffee and alcohol on skin, and dysplastic naevi.

BACKGROUND/PURPOSE: Near infrared and impedance spectroscopy can be used for clinical skin measurements and need to be evaluated for possible confounding factors; (i) are skin conditions of the patient and the subsequent skin measurements influenced by alcohol and/or coffee consumption and (ii) are measurements of dysplastic naevi (DN) reproducible over time and significantly different compared to reference skin. METHODS: Near infrared and skin impedance spectroscopic data were analysed multivariately. In the first study, the skin characteristics of 15 healthy individuals were examined related to body location, gender, individual differences, and consumption of coffee or alcohol. The second study included five patients diagnosed with dysplastic naevi syndrome. Measurements were taken on DN and reference skin over time. RESULTS: In the first study, body location and gender had a major influence on measurement scores. Inter-individual skin characteristics and coffee or alcohol effects on skin characteristics were of minor importance. In the second study, it was shown that DN can be differentiated from reference skin and the measurements are stable over time. CONCLUSIONS: Moderate consumption of alcohol and coffee did not influence the results of the measurements. It is possible to follow, stable or changed, characteristics of DN over time.

Electrochemical impedance spectroscopy in label-free biosensor applications: multivariate data analysis for an objective interpretation.

Electrochemical impedance spectroscopy plays an important role in biosensor science thanks to the possibility of finding specific information from processes with different kinetics at a chosen electrode potential in one experiment. In this paper we briefly discuss label-free impedimetric biosensors described in the literature. A novel method for neutral interpretation of impedance data is presented that includes complex number chemometrics. Three examples are given based on impedance measurements on synthetic biomembranes, in this case a lipid monolayer deposited on a mercury electrode. The interaction of various compounds with the monomolecular lipid layer is illustrated with the following: (1) different concentrations of magainin (Geladi et al. in Proc. Int. Fed. Med. Biomed. Eng. 9:219-220, 2005); (2) different derivatives of gramicidin A (Lindholm-Sethson et al. in Langmuir 24:5029-5032, 2007), and (3) an antimicrobial peptide (Ringstad et al. in Langmuir 24:208-216, 2008).

Comparison of three instrumental methods for the objective evaluation of radiotherapy induced erythema in breast cancer patients and a study of the effect of skin lotions.

A non-blinded three armed study of the effect of Aloe vera, Essex and no lotion on erythema was performed. The erythema is an effect of radiotherapy treatment in breast cancer patients. The study required testing of objective methods for measuring the erythema. The chosen experimental methods were Near Infrared Spectroscopy, Laser Doppler Imaging and Digital Colour Photography. The experimental setup was made in such a way that in parallel with testing the effect of the lotions there was also a test of the sensitivity of the instruments. Fifty women were selected consecutively to participate in the study. They were all subjected to treatment with high-energy electrons (9-20 MeV) after mastectomy, 2 Gy/day to a total dose of 50 Gy. Measurements were performed before the start of radiotherapy and thereafter once a week during the course of treatment. Aloe vera and Essex lotion were applied twice every radiation day in selected sites. The increase in skin redness could be monitored with all techniques with a detection limit of 8 Gy for Digital Colour Photography and Near Infrared Spectroscopy and 18 Gy for Laser Doppler Imaging. In clinical practice our recommendation is to use Digital Colour Photography. No significant median differences were observed between the pairs no lotion-Essex, no lotion-Aloe vera and Essex-Aloe vera for any of the techniques tested.

Objective measurements of radiotherapy-induced erythema.

BACKGROUND/AIMS: The development of acute radiation erythema is a common phenomenon among patients under-going radiotherapy treatment. Because of the absence of reliable objective classification methods, the degree of skin reaction can at present mainly be judged subjectively in the clinic. This has motivated the present preliminary study,concerning the first steps in the development of an objective method for skin reaction classification. METHODS: Three non-invasive techniques were used:near-infrared (NIR) spectroscopy, laser Doppler perfusion imaging and digital photography. The NIR spectra were analysed with principal component analysis (PCA), and the results from the other two with traditional univariate methods. Measurements were made on breast cancer patients who had been exposed to different irradiation doses. A total of 28 breast cancer patients participated one to three times each; 12 were treated with photons at 4 or 6MeV and 16 were treated with high-energy electrons between 10 and 20 MeV to a maximum dose of 50 Gy. RESULTS: PCA of NIR spectra shows that information on radiation dose lies mainly in the first principal component. It is observed that the higher the dose the higher the score value. The results from the laser Doppler measurements show that in 79% of the cases the perfusion increases significantly with radiation dose. Analysis of the digital photography shows that a proposed skin redness index(SRI), increases with a higher radiation dose. However,the increase in most cases is not significant. By combining all data, correlation to radiation doses was seen for 74% of the patients who participated more than once. CONCLUSION: All three non-invasive methods correlate with the radiation dose but to various degrees. NIR spectroscopy, laser Doppler and a combination of the three techniques are the most promising methods for characterising erythema.

Are biosensor arrays in one membrane possible? A combination of multifrequency impedance measurements and chemometrics.

A novel concept of a membrane-based micro-array biosensor is presented. The methodology is based on a single lipid membrane interrogated with electrochemical impedance techniques followed by multivariate data analysis. A single membrane is designed so that relaxation processes with a range of time constants can be probed at different potentials. A range of other approaches cited in the literature is reviewed.

Gramicidin A interaction at a dioleoyl phosphatidylcholine monolayer on a mercury drop electrode.

A biosensor where the sensing surface is a fluid dioleyl phosphatidylcholine monolayer (DOPC) deposited on a mercury drop was used. The lipid monolayer was held in 0.1 M NaCl and a concentration of gramicidin A in the range 0-12 nM was used. Electrochemical impedance spectroscopy in the frequency range 0.1-65 kHz was employed to investigate how the defect-free monolayer responds to interactions of gramicidin A in solution. The data was analyzed both with multivariate data analysis and classical electrochemical methods. The principal component analysis of the resulting impedance spectra gave a linear dependence on the concentration of gramicidin A. An increasing permittivity was observed in the low-frequency regime with increasing concentration of gramicidin A in solution.