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J Welzel

Publications and source records attributed to J Welzel.

16 recordsLinked to original sources
PubMed2006

Evaluation of the atrophogenic potential of different glucocorticoids using optical coherence tomography, 20-MHz ultrasound and profilometry; a double-blind, placebo-controlled trial.

BACKGROUND: Skin atrophy is one of the main side-effects of topical corticosteroid therapy. Although the use of high-frequency ultrasound is an established method that has been studied previously, it allows measurements of the slow-reacting dermal thickness only. OBJECTIVES: To investigate the decreasing epidermal thickness, which occurs earlier, we used optical coherence tomography (OCT), a high-resolution noninvasive imaging technique, and compared it with 20-MHz ultrasound and profilometry. PATIENTS/METHODS: In this double-blind placebo-controlled trial 20 healthy volunteers applied four different corticosteroids and the cream base formulation as placebo to the volar part of both arms once a day over a 4-week period. The epidermal thickness, the dermal thickness and the skin surface roughness were assessed using OCT, high-frequency ultrasound and profilometry. RESULTS: Each of the three methods allowed the detection and monitoring of significant corticosteroid-induced skin atrophy and its reversibility. The changes correlated with the potency of the steroids. The epidermal thickness decreased significantly in all test areas, even in the placebo and the untreated fields. As expected, the reduction in epidermal thickness was more pronounced and could be detected earlier by OCT than the reduction of dermal thickness using ultrasound. The epidermal surface roughness investigated using profilometry showed a slight smoothing. CONCLUSIONS: OCT allows a simple, fast and noninvasive in vivo measurement of the epidermal thickness. To evaluate the atrophogenic potential of corticosteroids it is more suitable than high-frequency ultrasound as epidermal thickness decreases earlier. In addition, epidermal thickness is a more sensitive indicator of steroid atrophy as the degree of thinning is much higher compared with the dermal atrophy. Profilometry might give further information; however, it would not be suitable for clinical use as the results were generally less pronounced. In the future, OCT might be useful to detect corticosteroid-induced side-effects at the beginning for monitoring the therapy.

Adult↗
PubMed2004

Changes in function and morphology of normal human skin: evaluation using optical coherence tomography.

BACKGROUND: Optical coherence tomography (OCT) is a noninvasive morphological method for investigating human skin. It allows high-resolution in vivo imaging of inflammatory skin diseases and tumours. Because it is a newly developed method, systematic studies on standardization and on evaluation of factors influencing the representation of the skin have not yet been performed. OBJECTIVES: In this study, normal human skin was treated with various external stimuli which induce changes of function and morphology. Changes in stratum corneum thickness as well as changes induced by pigmentation, oedema and erythema were investigated using OCT. METHODS: Healthy skin of human volunteers was treated with tape stripping, ultraviolet A irradiation, water, histamine, nicotinic acid and various ointments. RESULTS: In the tape stripping experiment, the thickness of the horny layer was quantified and monitored. Pigmentation increased the light attenuation of the tissue, whereas hydration and erythema led to a slight decrease of scattering. Topical treatment of the skin gave a nonspecific increase of penetration depth of the light due to the lower reflectivity of the surface. CONCLUSIONS: There are various physiological conditions which influence optical properties of the skin. These parameters should be considered when performing standardized OCT studies.

Adult↗
PubMed2001

Optical coherence tomography in dermatology: a review.

BACKGROUND/AIMS: Optical coherence tomography (OCT) is a non-invasive technique for morphological investigation of tissue. Since its development in the late 1980s it is mainly used as a diagnostic tool in ophthalmology. For examination of a highly scattering tissue like the skin, it was necessary to modify the method. Early studies on the value of OCT for skin diagnosis gave promising results. METHODS: The OCT technique is based on the principle of Michelson interferometry. The light sources used for OCT are low coherent superluminescent diodes operating at a wavelength of about 1300 nm. OCT provides two-dimensional images with a scan length of a few millimeters (mm), a resolution of about 15 microns and a maximum detection depth of 1.5 mm. The image acquisition can be performed nearly in real time. The measurement is non-invasive and with no side effects. RESULTS: The in vivo OCT images of human skin show a strong scattering from tissue with a few layers and some optical inhomogeneities. The resolution enables the visualization of architectural changes, but not of single cells. In palmoplantar skin, the thick stratum comeum is visible as a low-scattering superficial well defined layer with spiral sweat gland ducts inside. The epidermis can be distinguished from the dermis. Adnexal structures and blood vessels are low-scattering regions in the upper dermis. Skin tumors show a homogenous signal distribution. In some cases, tumor borders to healthy skin are detectable. Inflammatory skin diseases lead to changes of the OCT image, such as thickening of the epidermis and reduction of the light attenuation in the dermis. A quantification of treatment effects, such as swelling of the horny layer due to application of a moisturizer, is possible. Repeated measurements allow a monitoring of the changes over time. CONCLUSION: OCT is a promising new bioengineering method for investigation of skin morphology. In some cases it may be useful for diagnosis of skin diseases. Because of its non-invasive character, the technique allows monitoring of inflammatory diseases over time. An objective quantification of the efficacy and tolerance of topical treatment is also possible. Due to the high resolution and simple application, OCT is an interesting addition to other morphological techniques in dermatology.

Dermatology↗
PubMed2001

Influence of body water distribution on skin thickness: measurements using high-frequency ultrasound.

BACKGROUND: Although it is known that the skin acts as a water reservoir and participates in the fluid content of the whole body, no method has been established to quantify the fluid shifts in superficial tissue. OBJECTIVES: The aim of this study was to investigate changes in dermal and subcutis thickness and echodensity at the forehead and lower leg by high-frequency (20 MHz) ultrasound under various physiological conditions influencing water balance. METHODS: These parameters were measured in the skin of 20 healthy male volunteers at baseline and successively at 30 min after lying down, in a head-down position, after physical activity and after infusion of 10 mL kg-1 body weight of Ringer's solution. RESULTS: Dermal thickness at the forehead showed a significant increase from baseline to a horizontal position and a further increase in the head-down position. Physical activity did not lead to further changes, whereas after fluid infusion the dermal thickness also increased markedly. The echodensity showed inverse changes, with decreasing values. The thickness of the subcutis increased slightly from baseline to a lying position and decreased in the head-down position and after fluid infusion. At the lower leg, skin thickness decreased slightly in the head-down position with elevated legs, and increased after fluid infusion. CONCLUSIONS: Our results show that slight changes in the water distribution of the body influence the thickness and the echodensity of the dermis. Changes are more pronounced at the forehead than on the lower legs. Further, the fluid storage takes place mainly in the dermis and not in the subcutis. High-frequency ultrasound is able to quantify these effects and is a sensitive method for measuring fluid intake and balance during anaesthesia and therapy.

Adult↗
PubMed1999

[Ranking of 20 MHz sonography of malignant melanoma and pigmented lesions in routine diagnosis].

PURPOSE: Eleven dermatology clinics from all over Germany took part in our multicenter prospective study with the aim of evaluating 20 MHz sonography in the preoperative diagnosis of malignant melanomas and other pigmented skin tumours. It was to be assessed how effective sonographic measurement of thickness would compare to histology and the clinical palpation of tumour thickness and also the significance of differential diagnosis in sonography of malignant melanomas. METHOD: The prospective multicenter study proceed as follows. To the end of August 1997 264 patients with a primary malignant melanoma and 417 patients with benign skin tumours were examined via 20 MHz sonography. Two different examiners estimated the clinical thickness of the tumour by palpation. The tumour was then excised and examined for postoperative correlation with the histology sections. RESULTS: The final results showed good correlation between the histological and sonographic estimation of tumour thickness (r = 0.97). Estimation of tumour thickness by palpation showed no correlation with the histology (r = 0.59). Most of the benign (44%) and malignant tumours (38.7%) were spindle shaped. There was no significant difference between the benign and malignant tumour groups in relation to the sonographic presented shapes or echo signs. No different diagnosis could be made. CONCLUSION: The technique of high frequency sonography in relation to preoperative diagnosis of malignant melanomas has high priority. In contrast to clinical estimation of tumour thickness, sonography provided a good correlation to histology. The effectiveness of sonography with regard to the valence of the skin tumours is limited and there is no possibility of differentiating between malignant and benign tumours from the morphological face value. Hence, there is a demand for developing a 150 MHz apparatus which will be able to supply evidence regarding the valence of skin tumours.

Diagnostic Tests, Routine↗
PubMed1998

SLS-irritated human skin shows no correlation between degree of proliferation and TEWL increase.

It is well known that cutaneous irritants influence epidermal proliferation but the pathogenesis is poorly understood. Recent investigations have shown that the skin barrier integrity influences the proliferation of the basal keratinocytes. Our question was whether the proliferating activity of keratinocytes is indeed regulated by the degree of skin barrier damage or by a direct toxic action of the irritant on the keratinocytes. Therefore various degrees of skin irritation were induced by the application of 0.1%, 0.5% and 2% sodium lauryl sulphate (SLS) solution to the forearm skin of six healthy volunteers. This experiment was performed to evaluate the relationship between SLS concentration and epidermal proliferation. In a second experiment another 14 volunteers were treated with a single SLS concentration (0.5%) to look for interindividual differences in the patterns of skin reaction and susceptibility to the irritant. Skin barrier function was evaluated by measurements of transepidermal water loss (TEWL) before and after irritation. Punch biopsies were taken after 96 h from exposed areas and from unexposed normal skin. Dividing keratinocytes were identified immunocytochemically using three different monoclonal antibodies: PCNA, MIB 1 and KiS1. Exposure to SLS resulted in concentration-dependent increases in both TEWL and epidermal proliferation. However, no significant correlation could be found between the degree of hyperproliferation and the TEWL changes. The results suggest that epidermal proliferation is modulated by a direct interaction of the surfactant with the keratinocytes and/or by release of mediators rather than the consequence of a barrier disturbance.

Adult↗
PubMed1998

The influence of female sex hormones on skin thickness: evaluation using 20 MHz sonography.

Changes in skin thickness and echodensity during the spontaneous menstrual cycle, in women taking hormonal contraceptives and pregnant women were investigated by high-frequency (20 MHz) ultrasound. Women with a spontaneous ovulatory menstrual cycle (group I), women taking one-phase contraceptives (group II), women taking three-phase contraceptives (group III) and pregnant women (group IV) were measured at the following locations: proximal and distal forearm and lower leg on both sides. The skin was investigated during three phases of the menstrual cycle: days 2-4 (phase A), days 12-14 (phase B) and days 20-22 (phase C). Oestradiol and progesterone levels were determined at each phase. The pregnant women were investigated 2 weeks prepartal and 6 weeks after delivery. Group I showed a statistically significant increase in the skin thickness from phase A to phase B, but not from phase B to phase C. Group II showed no significant changes in skin thickness, whereas the skin thickness increased from phase A to phase B in group III. In group IV, the skin was significantly thicker prepartal than after delivery. The measured echodensity showed a negative correlation with skin thickness in group III and in pregnant women. We were able to demonstrate that the status of female sex hormones influences the thickness of the skin. These results can be explained by hormone-induced water retention in the skin. Sonography at 20 MHz is able to quantify these effects, which should be considered when performing ultrasound measurement in women.

Adult↗
PubMed1998

Tropical rat mite dermatitis: case report and review.

Six medical students inhabiting a centuries-old, rat-infested house in Lübeck, in northern Germany, were suffering from itching papules and seropapules. Prior to these patients' visit to our institute, their conditions had been diagnosed as pediculosis, scabies, or pulicosis and treated unsuccessfully with the antiparasitic agent lindane (0.3%). The final diagnosis, tropical rat mite dermatitis, was based on the identification of the arthropod Ornithonyssus bacoti, which has an unsegmented body with eight legs. No treatment was recommended, and the dermatitis disappeared within 2 weeks. Measures taken to prevent reinfestation included extermination of the rats and treatment of the rooms of the house with the acaricide benzyl benzoate. Because the mite O. bacoti spends a relatively short time on a host and penetrates the skin for feeding only, the application of an antiparasitic agent is not necessary. If indicated, treatment should be symptomatic.

Adult↗
PubMed1998

Cardiomyopathic lentiginosis/LEOPARD syndrome presenting as sudden cardiac arrest.

A 26-year-old apparently healthy man with numerous pigmented skin lesions collapsed during an evening party and was resuscitated from ventricular fibrillation. Hypertrophic cardiomyopathy and subaortic tunnel were disclosed by angiocardiography. A diagnosis of cardiomyopathic lentiginosis/lentigines (multiple), electrocardiographic abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of the genitalia, retardation of growth, and deafness (sensorineural) syndrome was made. The patient then underwent treatment with an implantable pacer-cardioverter-defibrillator device. Further evaluation revealed several well-established features of the disorder. This is the first reported case of survival from ventricular fibrillation associated with this rare and little known multifaceted syndrome. Disseminated lentiginosis must prompt clinicians to evaluate such cases further since underlying disorders may be associated with considerable morbidity and, apparently, sudden death.

Abnormalities, Multiple↗
PubMed1997

Optical coherence tomography of the human skin.

BACKGROUND: Optical coherence tomography (OCT) is a new diagnostic method for tissue characterization. OBJECTIVE: We investigated normal and pathologic structures in human skin in several locations to evaluate the potential application of this technique to dermatology. METHODS: Based on the principle of low-coherence interferometry, cross-sectional images of the human skin can be obtained in vivo with a high spatial resolution of about 15 microns. Within a penetration depth of 0.5 to 1.5 mm, structures of the stratum corneum, the living epidermis, and the papillary dermis can be distinguished. RESULTS: Different layers could be detected that were differentiated by induction of experimental blisters and by comparison with corresponding histologic sections. Furthermore, OCT images of several skin diseases and tumors were obtained. CONCLUSION: OCT is a promising new imaging method for visualization of morphologic changes of superficial layers of the human skin. It may be useful for noninvasive diagnosis of bullous skin diseases, skin tumors, and in vivo investigation of pharmacologic effects.

Adult↗
PubMed1996

Skin permeability barrier and occlusion: no delay of repair in irritated human skin.

It has been reported that occlusive treatment of irritated skin results in a reduction of barrier repair activities in hairless mice. In contrast, the clinically observed benefit of occlusion in the treatment of hand eczema and other chronic skin diseases with a perturbed barrier function is well-known. While the beneficial effect of occlusion has been proven for the treatment of psoriasis there are no controlled clinical studies of the effect of occlusion on irritated human skin. We have therefore evaluated the effect of various occlusive treatments on repair of the human skin permeability barrier under controlled experimental conditions. Barrier perturbation was induced either by application of sodium lauryl sulfate (SLS) or by repeated tape stripping. This was followed by treatment with different occlusive and semipermeable dressings, partly after pre-treatment with petrolatum. Repair of water barrier function was evaluated by daily measurements of transepidermal water loss (TEWL) for 1 week. SLS irritation and tape stripping led to a 6-fold increase in TEWL as a sign of severe water barrier perturbation, followed by a stepwise decrease over the following days. Occlusion did not significantly delay barrier repair as measured by TEWL. Only in tape-stripped skin did TEWL stay at high levels during treatment with self-adhesive dressings. This may be explained by damage of newly formed stratum corneum caused by changing of these membranes. Our results indicate that, in contrast to earlier observations in hairless mouse skin, permeability barrier repair activities are not significantly delayed by occlusive treatment in human skin.

Adult↗
PubMed1994

[Dermatoliposclerosis in 20 MHz ultrasound].

The degree of lipodermatosclerosis in chronic venous insufficiency was determined by high-resolution 20 MHz ultrasound. For comparison, skin biopsies were taken and examined by light microscopy. With increasingly extensive sclerosis, ultrasound showed increasing thickness of the dermis with a poorly defined border from the subcutaneous fat. In addition, an echolucent band appeared in the upper dermis, corresponding to regions of glomerular capillaries in histology. In our experience, high-resolution ultrasound examination allows rapid and objective quantification of lipodermatosclerosis.

Adipose Tissue↗
PubMed1993

[Localization and degree of expression of dermatoliposclerosis can be well evaluated with 20 MHz ultrasound].

33 legs of patients with chronic venous insufficiency and 21 legs of healthy persons were examined by high resolution 20 MHz ultrasound. With increasing lipodermatosclerosis--which was most pronounced in the medium part of the lower leg--an increase of thickness and a decrease of echo density of the dermis could be seen. The first sign of decreased density was an echolucent band in the upper part of the dermis. While in healthy subjects dermis and subcutaneous fat were clearly separated in ultrasound, in mild sclerosis differentiation was more difficult; in extensive lipodermatosclerosis it often was not possible to distinguish these parts of the skin. Localisation and extent of lipodermatosclerosis can be well demonstrated and evaluated by 20 MHz ultrasound.

Adipose Tissue↗