Simple horizontal averaging programme enables shade correction for image analysis in psoriasis

Potential mobile units drive the horizontal transfer of phytoplasma effector phyllogen genes

Phytoplasmas are obligate intracellular plant pathogenic bacteria that can induce phyllody, which is a type of abnormal floral organ development. Phytoplasmas possess phyllogens, which are effector proteins that cause phyllody in plants. Phylogenetic comparisons of phyllogen and 16S rRNA genes have suggested that phyllogen genes undergo horizontal transfer between phytoplasma species and strains. However, the mechanisms and evolutionary implications of this horizontal gene transfer are unclear. Here, we analyzed synteny in phyllogen flanking genomic regions from 17 phytoplasma strains that were related to six 'Candidatus' species, including three strains newly sequenced in this study. Many of the phyllogens were flanked by multicopy genes within potential mobile units (PMUs), which are putative transposable elements found in phytoplasmas. The multicopy genes exhibited two distinct patterns of synteny that correlated with the linked phyllogens. The low level of sequence identities and partial truncations found among these phyllogen flanking genes indicate that the PMU sequences are deteriorating, whereas the highly conserved sequences and functions (e.g., inducing phyllody) of the phyllogens suggest that the latter are important for phytoplasma fitness. Furthermore, although their phyllogens were similar, PMUs in strains related to 'Ca. P. asteris' were often located in different regions of the genome. These findings strongly indicate that PMUs drive the horizontal transfer of phyllogens among phytoplasma species and strains. These insights improve our understanding of how symptom-determinant genes have been shared among phytoplasmas.

Incorporating Colour Information for Computer-Aided Diagnosis of Melanoma from Dermoscopy Images: A Retrospective Survey and Critical Analysis

Cutaneous melanoma is the most life-threatening form of skin cancer. Although advanced melanoma is often considered as incurable, if detected and excised early, the prognosis is promising. Today, clinicians use computer vision in an increasing number of applications to aid early detection of melanoma through dermatological image analysis (dermoscopy images, in particular). Colour assessment is essential for the clinical diagnosis of skin cancers. Due to this diagnostic importance, many studies have either focused on or employed colour features as a constituent part of their skin lesion analysis systems. These studies range from using low-level colour features, such as simple statistical measures of colours occurring in the lesion, to availing themselves of high-level semantic features such as the presence of blue-white veil, globules, or colour variegation in the lesion. This paper provides a retrospective survey and critical analysis of contributions in this research direction.

Measurement of body surface area in atopic dermatitis using specific PC software (ScoradCard)

In skin diseases, evaluation of involved surface area is a crucial factor in grading the degree of severity. We examined the reliability of body surface area assessment and relative inter-observer and intra-observer variability using new software (ScoraCard), specifically designed to evaluate automatically the extension of the involved area in the SCORAD index. Twenty pediatricians, untrained in the evaluation of skin disease, estimated the percentage of surface area involved in photo-tests of two children with artificial well-delimited lesions, at first by sight and then through software. As "gold standard" the exact amount of pixels was counted for the whole body surface of the children, for the different body zones and for the painted artificial lesions, expressed as percentage of the respective zone. For photo 1, gold standard was 38.06% and median percentage was 43.44% (95% CI 40.7-46.21) by sight (p = 0.002) and 37.99% (95% CI 36.04-39.94) by ScoradCard (p = 0.79). For photo 2, gold standard was 27.84%, median percentage was 30.44% (95% CI 28.25-32.63) by sight (p = 0.047) and 27.8% (95% CI 26.55-29.04) by ScoradCard (p = 0.79). The level of agreement (kappa statistic), cumulative for the two photo tests, was 0.38 (fair agreement) by sight method and 0.67 (good agreement) by ScoradCard. Among the 10 pediatricians who repeated the computer aided evaluation 3 months apart, the intra-observer variability was not significantly different: the median percentage was 31.5% (95% CI 27.0-49.4) at time 0 and 29.0% (95% CI 26.7-47.2) 3 months later (p = 0.76). This new software could be a useful tool in evaluating skin lesions extension, minimizing inter- and intra-observer variability, which is an important goal in multi-centre studies.

Measurement of epidermal thickness in a patient with psoriasis by computer-supported image analysis

The aim of the present study was to measure full epidermal thickness, stratum corneum thickness, rete length, dermal papilla widening and suprapapillary epidermal thickness in psoriasis patients using a light microscope and computer-supported image analysis. The data obtained were analyzed in terms of patient age, type of psoriasis, total body surface area involvement, scalp and nail involvement, duration of psoriasis, and family history of the disease. The study was conducted on 64 patients and 57 controls whose skin biopsies were examined by light microscopy. The acquired microscopic images were transferred to a computer and measurements were made using image analysis. The skin biopsies, taken from different body areas, were examined for different parameters such as epidermal, corneal and suprapapillary epidermal thickness. The most prominent increase in thickness was detected in the palmar region. Corneal thickness was more pronounced in patients with scalp involvement than in patients without scalp involvement (t=-2.651, P=0.008). The most prominent increase in rete length was observed in the knees (median: 491 microm, t=10.117, P=0.000). The difference in rete length between patients with a positive and a negative family history was significant (t=-3.334, P=0.03), being 27% greater in psoriasis patients without a family history. The differences in dermal papilla distances among patients were very small. We conclude that microscope-supported thickness measurements provide objective results.

Optical non-invasive approaches to diagnosis of skin diseases

A number of noninvasive approaches have been developed over the years to provide objective evaluation of the skin both in health and in disease. The advent of computers, as well as of lasers and photonics, has made it possible to develop additional techniques that were impossible a few years ago. These approaches provide the dermatologist with sensitive tools to measure the skin's condition in terms of physiologic parameters (e.g., color, erythema and pigmentation, induration, sebaceous and stratum corneum lipids, barrier function, etc.). Yet, a typical dermatologic diagnosis relies primarily on the trained eyes of the physician and to a lesser extent on information from other senses, such as touch and smell. The trained senses of the dermatologist backed by his/her brain form a powerful set of tools for evaluating the skin. The golden rule in diagnosis remains the histologic examination of a skin biopsy, a rather invasive method. These tools have served the profession well. The advent of ever faster and cheaper computers and of sensitive, inexpensive optical instrumentation of minimal dimensions provides the professional with the possibility of making objective measures of a number of skin parameters.