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M Stücker

Publications and source records attributed to M Stücker.

88 records · Page 5Linked to original sources
PubMed1997

[High resolution 20 MHz ultrasound diagnosis in dermatology for noninvasive imaging of malignant melanomas].

For years, high-resolution b-scan ultrasound is a well established technique in dermatology regarding the preoperative determination of thickness of skin tumors like malignant melanoma or basal cell carcinoma. Most tumors appear as echopoor areas in high-frequency sonography. Until today, a differentiation between skin tumors by means of high-frequency ultrasound is not possible. This is also true concerning the differentiation between the tumor tissue itself and its subtumoral inflammatory infiltration. Therefore, this lack of differentiation leads to the fact that sonometric thicknesses of tumors often exceed the originally measured tumor thickness in histology. By means of three-dimensional reconstruction of serial b-scan images, it is possible to determine each tumor's volume and surface as well as the topographical arrangement of echopoor areas and sonographical structures. Besides high-frequency ultrasound, additional non-invasive techniques like MRI, ultrasound- or laser-doppler, computer-aided image analysis and epiluminescence microscopy are also available for diagnosing malignant melanoma. Epiluminescence microscopy is used today as a standard technique in the diagnosis of malignant melanoma due to the possibility of differential diagnosis. Latest techniques like OCT (optical coherence tomography) are not ready yet to be applied regularly in diagnosis of tumors in the field of dermatology.

Diagnosis, Differential↗
PubMed1995

Precision of laser Doppler scanning in clinical use.

Reactions of the cutaneous microcirculation to local stimuli have been quantitated in terms of area of erythema (planimetry), change in colour (colorimetry) and time-dependent changes in perfusion (one-dimensional laser Doppler fluxmetry (LDF)). Using the new technique of laser Doppler scanning (LDS) it is now possible to quantify and demonstrate two-dimensional patterns of microvascular perfusion in terms of intensity and extent. The precision of this new technique was compared with the previously established techniques by examining the reactions of 15 healthy volunteers to the intracutaneous injection of carbacholin and isotonic NaCl solutions. Both stimuli were applied paravertebrally, on the left and right side. Reactions were examined after 10 min. As a control for temporal reproducibility the examination was repeated on another day. All methods allowed the differentiation of reactions to carbacholin from those to NaCl (P < or = 0.0001). Only colorimetry and LDS provided data that were unequivocally reproducible when comparing both sides (r > or = 0.78). Using LDF or planimetry, reproducibility of values was lower (r < or = 0.58). When looking at measurements performed on different days, only values of LDS were reproducible (r > or = 0.77). Hyperaemic areas seen with LDS were significantly larger than those determined by planimetry. Results of LDS are reproducible spatially and temporally: the technique will allow time-course observations of skin reactions that are accompanied by medium-term changes in perfusion.

Adult↗
PubMed1995

Cutaneous microcirculation in skin lesions associated with chronic venous insufficiency.

BACKGROUND: There are various types of skin lesions in chronic venous insufficiency. OBJECTIVE: To determine an association between different skin lesions and different changes in the cutaneous vascular bed. METHODS: Twenty-eight patients with chronic venous insufficiency (CVI) without and with various types of skin lesions (ie, hyperpigmentation, lipodermatosclerosis, white atrophy, and venous ulcer) and 12 healthy control subjects were examined by video-capillaroscopy, transcutaneous oxygen tension measurement, photoplethysmography, and Doppler ultrasonography to detect disturbances of cutaneous microcirculation and venous macrocirculation. RESULTS: There were no significant differences between the different CVI groups with respect to their venous function disorder. However, important variations were noted in the cutaneous microcirculation. In all the patient groups, an increase in the mean halo diameter could be demonstrated even in clinically healthy skin. In all types of skin lesions, the mean capillary diameter was significantly enlarged. Severe morphological capillary changes and a significant reduction of the mean transcutaneous oxygen tension values were found in conjunction with lipodermatosclerosis and white atrophy and in the areas surrounding venous ulcers. CONCLUSION: The results of this study point to the conclusion that, once they have become established, microvascular disturbances play an independent role in the development of the skin lesions associated with CVI.

Adult↗
PubMed1995

Two-dimensional blood flow determinations in allergic reactions using laser Doppler scanning.

The new technique of laser Doppler scanning (LDS) provides a 2-dimensional pattern of cutaneous microcirculation, which offers a visual image and can quantify the intensity and expansion of perfusion. With the help of this technique, we examined the microcirculatory pattern of Type IV reactions to recall antigens, which were applied using a test stamp (Multitest Merieux). The measurements were performed before application of the test stamp as well as 10 min, 24, 48 and 72 h afterwards. The inflammatory hyperemia was evaluated using LDS and unidimensional laser Doppler fluxmetry. The diameter of the inflammatory infiltrate was quantified by means of palpation, the thickness by means of high-resolution 20 MHz sonography. The clinically visible erythema was measured planimetrically. An unspecific hyperemia resulting from the trauma of the stamp revealed no evident infiltrate under sonography 10 min after the test application. Depending of the individual reaction, the mean flux and the expansion of the hyperemia were at their peak after 48 h. The flux values were at a maximum in the center of the inflammatory reaction and dropped continuously toward the periphery. The area of the hyperemia seen in the LDS image was significantly larger than the expansion of the erythema measured planimetrically, but there was a significant correlation. The perfusion correlated significantly with the infiltration diameter (24 h, 48 h, 72 h) and the infiltration thickness 48 h after testing. All in all, it was possible to measure directly and without touching the skin and to quantify a subclinical pattern of skin perfusion as a response to and inflammatory reaction on a 2-dimensional display.

Adult↗
PubMed1995

[Objectivity, reproducibility and validity of 3D ultrasound in dermatology].

Recently it has become possible to visualize the three-dimensional (3D) architecture of sonographic structures using high-resolution ultrasound above 20 MHz (Dermascan C, Denmark; DUB 20, Germany). We studied the objectivity, reproducibility, and validity of these two 3D analysis systems on 22 skin tumors. To validate both systems, we compared the sonometric and histometric volume in 4 tumors. The objectivity was calculated by repeated evaluation of the volume on the same serial B-scan sections at 3-month intervals. The two-dimensional B-scans and 3D images exhibited similar characteristics. Volumetric evaluations were reproducible with both systems (variation coefficient < or = 9.9%), when the applicator was oriented longitudinal to the body axis. By changing the orientation, the coefficient increased up to 58.1% (DUB 20). Sonometric and histometric volumes of a phantom model and of the tumors exhibited small deviations in the Dermascan C (< or = 8.1%) and in some tumors large deviations in the DUB 20 (< or = 93.1%). We can conclude that the 3D sonography is a reproducible method, which can be used to evaluate the volume of skin tumors and metastases under chemotherapy or radiotherapy. We suggest in particular to use the in-vivo tumor volume as a prognostic parameter for the malignant melanoma.

Adult↗
PubMed1994

[History of high frequency sonography].

The development of high frequency sonography (< 20MHz) has gained increasing importance since the last decade. In this field A-mode-scanner were used firstly in the measurement of skin thickness. 1987 the first commercial available 20 MHz B-scanning system was introduced. These systems provided the possibility of correlating the ultrasound images with the micromorphological findings in histology. With these correlations we were able to interpret ultrasound phenomena and in conclusion we were able to measure tumour thicknesses with direct impact on the therapeutic regimen. In inflammatory skin diseases the role of high frequency ultrasound in follow up investigations of morphea and systemic sclerosis must be underlined. We believe that in this field the technique is the "golden standard". In other inflammatory diseases (e.g. psoriasis) or wound healing ultrasound is mainly used for scientific purposes. The investigation of intraepidermal structures and differential diagnosis is only possible with higher frequencies than 20 MHz. Therefore we developed 50 and 100 MHz in vivo scanning systems. With resolution up to 11 microns (100 MHz) we hope to answer open questions in the future. Ultrasound microscopy is widely used for scientific evaluation of tissue morphology in vitro (resolution < 1 micron). Computer-based three-dimensional reconstructions provide additional information (e.g. tumour volume or tumour surface). These parameters are well suited to follow up the effect of systemic or local therapies on skin metastases of different cancers. However, also the tumour volume of the primary tumour (in vivo) might be of great interest as a prognostic parameter in future.(ABSTRACT TRUNCATED AT 250 WORDS)

Dermatitis↗
PubMed1994

Evaluation of the efficacy of H1 blockers by noninvasive measurement techniques.

BACKGROUND: Evaluation techniques for determining the strength of action and the onset of activity of H1 receptor blockers have not yet been sufficiently standardized. OBJECTIVE: The clinical efficacy of the H1 receptor blocker loratadine was to be measured upon a wheal response subsequent to an intracutaneous injection of 0.1 ml histamine (0.1%). METHODS: In a pilot study, 10 patients were treated with the H1 receptor blocker loratadine for a period of 7 days. Various noninvasive measurement techniques, i.e. 20-MHz sonography, laser-Doppler flowmetry, chromatometry using the Lab* system and computer-assisted planimetry, were applied to provide a quantitative evaluation of the wheal and the marginal erythema. Using these quantification methods, the development of the urticarial reaction 20 min after injection and its decline were evaluated. RESULTS: The urticarial reaction was reduced substantially under treatment with 10 mg loratadine over a period of 7 days. The methods we used could accurately quantify different aspects of the urticarial reaction noninvasively. CONCLUSIONS: All of the chosen measurement techniques are widely recognized. For objective assessment of the urticarial reaction with high-frequency ultrasound, we recommend the measurement of the distance between skin entrance echo and fascia since the demarcation of the wheal is often impossible by ultrasound. In order to improve comparison of results of various workgroups in the future, we therefore suggest the use of the selected combination of noninvasive procedures as a standard for evaluating the efficacy of H1 receptor blockers.

Administration, Oral↗
PubMed1994

Assessment of actinic skin damage by 20-MHz sonography.

Ninety people were evaluated on age-related changes of the dermal connective tissue in light-exposed and protected skin areas non-invasively by 20-MHz sonography. The method allows sonographic structures to be measured and densitometric values to be quantified in a region of interest. Sonography of sun-exposed skin regions shows an echo-poor band in the upper dermis, which corresponds to actinic elastosis in the histological picture. The band is sharply demarcated from the entry echo. The border towards the non-actinically altered dermis below is often serrated. The sonographic phenomena can be explained by the micromorphological changes that develop in the upper dermis in actinic elastosis. An increased amount of elastic material and the destruction of the fiber architecture as well as an increase in ground substance and a mild inflammatory reaction cause a reduction in echogenicity. The extent of elastotic alterations and their progression is expressed in the densitometric values. These are low in areas of high sun exposure (the forehead and the infraorbital region). The echogenicity of the echolucent band (ELB) diminishes with increasing age. In highly exposed regions we found the lowest densitometric values already in the 41- to 50-year-olds. However, the width of the ELB remains relatively constant, extending in all locations to the middle dermis. This finding differs from earlier publications. On the buttock skin as a nonexposed area, an ELB could only be found in 6.7% of the cases.

Adipose Tissue↗
PubMed1994

The hyperperfusion of the psoriatic plaque correlates histologically with dilatation of vessels.

We examined psoriatic lesions on the upper legs in 20 patients, using a two-dimensional Laser-Doppler-Scanner (Laser Doppler Perfusion Imager LDI, Lisca Development, Linköping/Sweden). The plaques were evaluated weekly during therapy with dithranol. Five plaques were reconstructed three-dimensionally before and after therapy (reconstruction program ANAT 3D, SIS, Münster, Germany). The psoriatic plaque was represented in the Laser Doppler Perfusion image as a sharply demarcated, hyperperfused area. The perfusion of the plaques dropped during therapy with dithranol to just slightly increased values, compared with normal skin (2.04 arbitrary units AU, healthy skin 1.1 AU). Using three-dimensional reconstruction, we investigated the volume of dermal vessels and the density of papillae. When compared, the volume of papillary vessels was twice as large in psoriatic as in healthy skin. The number of the papillae per square millimetre, detected by three-dimensional reconstruction, was not reduced significantly during therapy. We think that the increased perfusion of the psoriatic plaque is due to the combination of morphological (dilatation of vessels), dynamic (increased blood flow) and optical effects (reduced scattering and increased sampling depth of the laser-beam in acanthotic tissue).

Anthralin↗
PubMed1992

[An inverse course of Darier dyskeratosis follicularis].

A 56-year-old female patient had suffered from isolated, unclassified palmoplantar keratosis since childhood. During the climacteric horny papules appeared for the first time on the extremities and trunk. Histologically, the efflorescences on the body and the palmoplantar keratosis were classifiable as keratosis follicularis. Predilection sites of Darier's disease were spared. Altogether, the usual pattern of involvement was reversed.

Biopsy↗
PubMed1990

[1989 Bochum health education program for malignant melanoma].

The incidence rate of all skin cancer forms has been increasing during the last few decades. The incidence of malignant melanoma is important due to its very high malignancy and its growing spread especially among young patients. Malignant melanoma is mainly observed on the external skin and is therefore well suited for screening methods. During a campaign in the city of Bochum, 1226 patients were examined. A total of 9 malignant melanomas and 10 basal cell carcinomas were discovered. The statistical data show that most of the patients could be motivated to participate by regional media and not by supraregional media. The wide acceptance of our prevention week shows that prevention campaigns are feasible, important and necessary.

Adolescent↗
PubMed1990

[Digital 20 MHz sonography of basalioma in the B-scan].

Digital 20 MHz b-scan sonography is a new non-invasive tool in dermatological routine diagnostics. The 20-MHz linear scanner employed in this study has a signal penetration of 7 mm, a lateral resolution of 200 microns and an axial resolution of 80 microns. Seventy-five basal cell carcinomas were examined by ultrasound. An exact correlation of histological slides and sonographic images allowed us to explain the sonographic phenomena of basal cell carcinoma (BC). BCs exhibit a well-defined area with poor echoes; they sometimes even show a total loss of reflection. In the tumor parenchyma inhomogenously distributed internal echos were found. Below the tumor post-tumoral enhancement of the signal reflection is common (depending on the type of BC -up to 70%). Our results prove that digital 20 MHz ultrasonic imaging systems are well suited for studying the extension, thickness and tissue texture of basal cell carcinoma.

Adult↗
PubMedDate not supplied

UV transmission and UV protection factor (UPF) measured on split skin following exposure to UVB radiation--correlation with the minimal erythema dose (MED).

In this study the ultraviolet (UV) transmission of split skin exposed to UVB radiation and of non-exposed skin was compared in the 280-390 nm wavelength range and quantified. In addition, the correlation between the increase in the minimal erythema dose (MED) associated with a defined exposure to UVB and the ultraviolet protection factor (UPF) calculated from the transmission data was investigated. The study population consisted of 12 patients. Two pieces of split skin of the same thickness (0.3 mm) were taken from the right thigh of each patient. One specimen was removed from an area of non-exposed healthy skin and the other from an area which had been exposed to UVB radiation for a period of 12 days in which the initial dose of 1/3 MED was raised by 1/3 MED every 4 days. The split skin specimens were stretched over a special frame; subsequently, the UV transmission was determined with a spectrophotometer. The mean values obtained for UV transmission were all significantly below the initial data for non-exposed split skin. In the UV range of 280--390 nm, the transmission measured in the exposed specimens was 49.1% of the value measured in the non-exposed split skin (P<0.05). The corresponding values for the UVA range (315--390 nm) and the UVB range (280--315 nm) were 50.1% and 29.5%, respectively (P<0.05), based on the initial transmission data obtained from non-exposed skin. The clinical determination of MED after 12 days of exposure to UVB yielded mean values that were 3.2 times the initial values. Moreover, the mean UPFs calculated from the transmission data measured at the end of the 12-day exposure period were also about three times the initial values. The present study has thus established a significant correlation between the clinical MED values and the UPFs calculated from the transmission data measured following exposure to UVB.

Adult↗
PubMedDate not supplied

Differences in the two-dimensionally measured laser Doppler flow at different skin localisations.

The cutaneous microcirculation shows a significant heterogeneity. With high-resolution two-dimensional laser Doppler perfusion imaging (LDPI), spatial and temporal reproducible perfusion measurements can be reached. The objective of this study was the quantification of skin perfusion in 20 defined skin areas with LDPI, in 60 healthy young and old volunteers. The perfusion of the face was significantly higher than that of the trunk and extremities. The highest perfusion values were seen at the lips, 1.47 arbitrary units (AU), followed by the chin (0.99 AU), the nose (0.95 AU), the forehead (0.73 AU) and the cheek (0.72 AU). Mean perfusion, between 0.40 and 0.49 AU, was seen at the extremities and at the trunk. The lowest perfusion was found at the bottom (0.37 AU), on the back of the foot (0.36 AU) and on the soles (0.31 AU). There was a tendency to show higher perfusion values in men than in women (0.60 +/- 0.31 vs. 0.53 +/- 0.26 AU). Age-related differences in perfusion could not be demonstrated. In the evaluation of the perfusion of pathological skin, regional perfusion differences must be considered, whereas moderate age or gender differences between different investigation groups can be tolerated.

Adult↗
PubMedDate not supplied

The effect of the base on the kinetics of action of the capsaicinoid nonivamide: evaluation with a hyperemic test.

Because of their selective receptor-mediated action on cutaneous nociceptive C-fibers, the interest in capsaicinoids as topical analgetic drugs has been constantly growing over the past years. Knowledge of the pharmacokinetics seems particularly important for potential future clinical applications. Therefore, the aim of the present study was to investigate the influence of the type of preparation on the time course of action of the capsaicinoid nonivamide monitored by the axon-reflex-induced hyperemic action and area of erythema. Sixteen healthy subjects were included in the study. The hyperemic responses after application of nonivamide in an oil-in-water (O/W) emulsion and in a water-free ointment were assessed both by laser Doppler perfusion imaging and planimetry after 0, 15, 30, 45, 60, 120 and 240 min. They were compared with the reaction after application of the nicotinic ester nicoboxil and a combination of nonivamide and nicoboxil in the same preparations. Applied as a water-free ointment, nonivamide showed a slow onset of hyperemic action, reaching its maximum 45 min after application. When applied as an O/W emulsion, however, the increase in effect was high, reaching its maximum already after 30 min. Application of the nicoboxil preparations revealed a clearly lesser influence of the base regarding the onset of maximum effect. The combination of both substances showed an additive effect for both bases, and a maximum effect was found already after 15 min with both the water-free ointment and the O/W emulsion base. In conclusion, the results of the present study show that there appears to be a strong influence of the vehicle on the kinetics of action of capsaicinoids, and that the hyperemic test used in this paper is very useful for the quantitative determination of the pharmacokinetic properties of capsaicinoids. Moreover, the C-fiber-stimulating effect of capsaicinoids can, at least in part, be enhanced by combination with a nicotinic ester, even though these substances have no direct effect on the C-fibers.

Adolescent↗