Notizen: Summary Cutis marmorata telangiectatica congenita and vascular twin naevi are rare vascular anomalies in which focal acantholytic dyskeratosis is usually not observed. We describe a 44-year-old-man who presented for evaluation of skin lesions that had been present since birth. Physical examination revealed anaemic macules adjacent to a naevus telangiectaticus on the chest. Naevus anaemicus was also seen on the shoulders, arms, and left leg. There was bluish–reddish reticulate marking of the skin and cutaneous atrophy. Shortening and hypoplasia of the left leg was observed. Histologic examination of two biopsy specimens revealed focal acantholytic dyskeratosis. In vivo confocal laser scanning microscopy showed dilated capillaries and vessels of the upper dermal plexus in the telangiectatic and decreased capillary blood flow in the anaemic skin sites. The findings were consistent with a diagnosis of cutis marmorata telangiectatica congenita, vascular twin naevi, and incidental focal acantholytic dyskeratosis. The particularities of the present case are the following: firstly, the association of two rare vascular anomalies to which the genetic concept of mosaicism can be applied; secondly, the occurrence of incidental focal acantholytic dyskeratosis in sites of vascular naevi.

Notizen: Background  Apart from sunscreen lotions, clothing provides protection from acute and chronic sun damage. Therefore, it is very important to know the ultraviolet (UV) protection factor (UPF) of textiles, in particular of lightweight summer clothing. Usually, the UPF of a textile is determined by spectrophotometric assessment of the UV transmission (in vitro method). Objectives  To compare the relationship between in vitro tests and in vivo tests of UPF using solar simulators for determination of the minimal erythema dose (MED), applied to 30 different summer textiles. Methods  Thirty summer textiles were spectrophotometrically assessed, and UPFs were calculated with respect to the International Commission on Illumination (CIE) erythemal action spectrum.1 Based on the in vitro UPFs ‘on skin’ and ‘off skin’, in vivo testing was performed using a solar simulator for the determination of the MEDunprotected and MEDprotected. Results  The UPFs obtained from in vivo‘on skin’ testing were significantly (r = 0·95; P 〈 0·001) lower than the predicted in vitro UPFs. This disparity was also confirmed by chromometric assessment of the MED testing; the erythemal responses measured after textile protection were significantly (P 〈 0·001) higher than those obtained without protection. However, the in vivo‘off skin’ UPFs did not significantly (r = 0·98; P 〉 0·05) differ from the in vitro UPFs; comparison of the chromometrically assessed erythemal responses was also insignificant (P 〉 0·05). Conclusions  The different correlation between in vitro and in vivo measurements of the UPF may be due to the optical–geometrical properties of textiles and the different amount of direct and diffuse radiation passing through the spaces between the yarns. As spectrophotometric measurements of a textile may generally yield lower UPFs than those obtained under average field conditions, the in vitro test method provides ‘safe’ UPF values representing a ‘worst-case scenario’. In contrast to in vitro testing, in vivo methods are much more expensive and time-consuming. Thus, with respect to practicality, spectrophotometric measurements seem to be most suitable for the evaluation of UV protection of textiles.

Notizen: Using classical neuroanatomical retrograde tracing methods we investigated the retinal ganglion cells projecting to the nucleus of the optic tract and dorsal terminal nucleus of the accessory optic system (NOT-DTN) in macaque monkeys. Our main aim was to quantify the strength of the projection from the ipsilateral retina to the NOT-DTN. We therefore examined the number, distribution, and soma size of retinal ganglion cells involved in this projection. Electrophysiologically controlled small injections into the NOT-DTN revealed a clearly bilateral retinal projection originating mainly from the central retina but also involving peripheral retinal regions. Labelled cells were found nasally in the contralateral retina and temporally in the ipsilateral retina with some overlap in the fovea. The projection from the ipsilateral retina was 36–43% of that from the contralateral retina. On average, only 1–6% of the local population of ganglion cells projected to the NOT-DTN. Small soma size and large dendritic fields imply that in monkey rarely encountered, ‘specialized’ ganglion cells provide the direct retinal input to the accessory optic system (AOS). These results are discussed with respect to the symmetry of monocular horizontal optokinetic nystagmus (OKN) in primates.

Notizen: When reaching for an object we usually look at it before we touch it with the hand. This often unconscious eye movement prior to the arm movement allows guiding of the final part of the hand trajectory by visual feedback. We examined the temporal and spatial coordination of this control system by psychophysical measurements of eye and arm movements of naive human subjects looking or looking and pointing as fast as possible to visual targets in physical and virtual-reality setups. The reaction times of saccades to a step-displaced target were reduced, and the number of corrective saccades decreased, when the subject had to produce a corresponding simultaneous hand movement to the same target. The saccadic reaction time was increased when saccade and hand movement went in opposite directions. In a double-step task the reaction time for the second saccade was longer than for the first. Co-use of the hand leads to an additional increase of saccadic reaction time. Taken together this study shows an improvement in initial saccades if they are accompanied by hand movements to the same target. This effect might ensure that the reach target is foveated early and accurately enough to support the visual feedback control of the hand near the target. Longer reaction times for the second saccade to double-step displaced targets might reflect a saccadic refractory time intensified by simultaneous arm movements. These results are discussed in the light of recent findings from our laboratory on saccade- and reach-related neurons in the superior colliculus of macaque monkeys.

Notizen: Electrophysiological studies in animals suggest that visuomotor control of forelimb and eye movements involves reciprocal connections between several areas (striate, extrastriate, parietal, motor and premotor) related to movement performance and visuospatial coding of movement direction. The extrastriate area MT [V5 (hMT+) in humans] located in the ‘dorsal pathway’ of the primate brain is specialized in the processing of visual motion information. The aim of our study was to investigate the functional role of V5 (hMT+) in the control of visually guided hand movements and to identify the corresponding cortex activation implicated in the visuomotor tasks using functional magnetic resonance imaging. Eight human subjects performed visually guided hand movements, either continuously tracking a horizontally moving target or performing ballistic tracking movements of a cursor to an eccentric stationary target while fixating a central fixation cross. The tracking movements were back-projected onto the screen using a cursor which was moved by an MRI-compatible joystick. Both conditions activated area V5 (hMT+), right more than left, particularly during continuous tracking. In addition, a large-scale sensorimotor circuit which included sensorimotor cortex, premotor cortex, striatum, thalamus and cerebellum as well as a number of cortical areas along the intraparietal sulcus in both hemispheres were activated. Because activity was increased in V5 (hMT+) during continuous tracking but not during ballistic tracking as compared to motion perception, it has a pivotal role during the visual control of forelimb movements as well.

Notizen: Lichen sclerosus et atrophicus (LSA) is a chronic inflammatory skin disease characterized by white porcelain-like sclerotic skin lesions. It is most commonly seen in adult females and usually affects the genitoanal area. Extragenital LSA appears in 15–20% of cases. We report a 9-year-old Caucasian girl suffering from extragenital LSA that was resistant to conventional treatment. After 40 treatment sessions with low-dose UVA1 phototherapy, all skin lesions were resolved completely. Moreover, the improvement of skin status has been sustained during 6-months of follow-up. Long-wave UVA irradiation has been shown to induce intensively collagenase activity in human dermal fibroblasts. We suggest that UVA1 irradiation could be an effective treatment in patients suffering from extragenital LSA.

Notizen: In histological studies, it has frequently been demonstrated that ultraviolet (UV) exposure, in particular UVB, can induce significant thickening of the viable epidermis and/or stratum corneum. Since skin biopsy alters the original skin morphology and always requires an iatrogenic trauma, we aimed to introduce optical coherence tomography (OCT) in vivo for the investigation of changes of epidermal thickness (ET) following UVA1 and UVB irradiation. Twelve healthy subjects received daily 60 J/cm2 of UVA1 and 1.5 minimal erythema doses UVB on their upper back over 3 consecutive days. Twenty-four hours after the last irradiation, OCT assessments were performed on UV exposed and adjacent nonirradiated control sites. Data of ET as expressed by comparison of the averaged A-scans differed significantly between nonirradiated (94.2 ± 15.7 µm), UVA1 (105.4 ± 12.8 µm) and UVB (125.7 ± 22.1 µm) exposed sites. In comparison to the nonirradiated sites, UVA1 exposed skin showed significant (P = 0.022) increase of ET of 11% and UVB exposed sites a significant (P 〈 0.001) increase of 25%. ET of UVA1 and UVB exposed skin sites differed significantly (P =0.005). Our results obtained from OCT in vivo measurements confirm data of previous histological studies indicating that not only erythemogenic doses of UVB, but also suberythemogenic doses of UVA1 may have a significant impact on ET. OCT appears to be a promising bioengineering technique for photobiological studies. However, further studies are needed to establish its measurement precision and validity, and to investigate in vivo spectral dependence on UV induced skin changes such as skin thickening.

Notizen: Background  Early detection of melanomas by means of diverse screening campaigns is an important step towards a reduction in mortality. Computer-aided analysis of digital images obtained by dermoscopy has been reported to be an accurate, practical and time-saving tool for the evaluation of pigmented skin lesions (PSLs). A prototype for the computer-aided diagnosis of PSLs using artificial neural networks (NNs) has recently been developed: diagnostic and neural analysis of skin cancer (DANAOS).Objectives  To demonstrate the accuracy of PSL diagnosis by the DANAOS expert system, a multicentre study on a diverse multinational population was conducted.Methods  A calibrated camera system was developed and used to collect images of PSLs in a multicentre study in 13 dermatology centres in nine European countries. The dataset was used to train an NN expert system for the computer-aided diagnosis of melanoma. We analysed different aspects of the data collection and its influence on the performance of the expert system. The NN expert system was trained with a dataset of 2218 dermoscopic images of PSLs.Results  The resulting expert system showed a performance similar to that of dermatologists as published in the literature. The performance depended on the size and quality of the database and its selection.Conclusions  The need for a large database, the usefulness of multicentre data collection, as well as the benefit of a representative collection of cases from clinical practice, were demonstrated in this trial. Images that were difficult to classify using the NN expert system were not identical to those found difficult to classify by clinicians. We suggest therefore that the combination of clinician and computer may potentially increase the accuracy of PSL diagnosis. This may result in improved detection of melanoma and a reduction in unnecessary excisions.