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Biomedical subjects

Peter Altmeyer

Publications and source records attributed to Peter Altmeyer.

At least 37 records · Page 2Linked to original sources
PubMed2006

A pilot study to optimize laser-assisted hair removal using real-time high-speed infrared imaging.

OBJECTIVE: The aim of this study was to investigate thermal effects on the skin surface during laser-assisted hair removal using real-time high-speed infrared imaging. BACKGROUND DATA: Although hair laser removal (HLR) can be considered an inherently safe treatment, there may be approaches to optimise the benefit/risk ratio of this common therapeutic and cosmetic procedure. METHODS: In this pilot study on three subjects, a ruby laser equipped with a cryogen spray cooling (CSC) system was used to investigate the effect of different CSC durations and delay times between CSC and the laser impulse. Skin surface temperature (SST) was assessed in real-time using a high-speed infrared camera (ThermaCam Phoenix) and a special image analysis software (analySIS Doku). RESULTS: There was no substantial difference of SST between the use of CSC spurts of 10 and 20 msec (6.1 degrees C versus 5.7 degrees C). The use of single laser and cooling parameters revealed baseline SST of 31.7 degrees C, immediately after CSC (10 ms) SST of 6.5 degrees C, and after laser pulse SST of 47 degrees C. Using fluences of 10-20 J/cm(2), a marked difference in temperature was observed between the skin surface and hair (e.g., 26.7 degrees C versus 57.5 degrees C). SST of 62-64 degrees C was observed using fluences of 18-20 J/cm(2), resulting in adverse effects. A maximum SST of 59 degrees C was observed using a CSC spurt of 40 msec, whereas a maximum SST of 60 degrees C was recorded for 30, 20, and 10 msec. The use of CSC delay time of 600 msec revealed baseline SST of 34.6 degrees C, immediately after CSC (10 msec) SST of 5.2 degrees C, after 600 msec delay SST of 21.5 degrees C, and SST of 60 degrees C following the laser pulse. By contrast, 100 msec delay time revealed baseline SST of 34.8 degrees C, immediately after CSC (10 ms) SST of 7 degrees C, after 100 msec delay SST of 7.5 degrees C, and SST of 55.2 degrees C following the laser pulse. CONCLUSION: Our preliminary data indicate that side effects of HLR can be avoided using CSC duration of 10 msec with a delay of about 200 msec. Short delay times between the CSC and laser pulse seem to result in lower post-irradiation SST and may therefore lead to less adverse effects. With regard to the fluence used in HLR, it is of importance that the maximum SST remains below 60 degrees C. Based on these preliminary results, real-time high-speed infrared imaging seems to be an interesting method to study the thermodynamics on skin surface during laser treatment.

Adult↗
PubMed2006

Surgical treatment of axillary hyperhidrosis: a study comparing liposuction cannulas with a suction-curettage cannula.

BACKGROUND: Suction-curettage is a minimally invasive surgical approach for the treatment of focal axillary hyperhidrosis. Studies comparing the efficacy of different surgical cannulas are missing. Therefore, we gravimetrically compared a specially designed cannula versus 2 standard liposuction cannulas. METHODS: Axillary suction-curettage was performed in 42 patients (n = 42). Fourteen patients (n = 14) were operated with a 1-hole liposuction cannula, 14 patients (n = 14) with a larger 3-hole liposuction cannula, and 14 (n = 14) with a sharp suction-curettage cannula. Sweat rates in mg/min were measured by gravimetry before and 6 months after surgery. RESULTS: Sweat rate in the 1-hole liposuction cannula group was significantly reduced from 57.65 +/- 5.85 mg/min to 32.58 +/- 4.64 mg/min (P < 0.001), corresponding to a reduction of 44.15%. Patients operated with the larger 3-hole liposuction cannula showed a significant reduction of sweat rate from 63.95 +/- 8.25 mg/min to 33.14 +/- 6.25 mg/min (P < 0.001), corresponding to a reduction of 49.19%. The largest reduction of sweat rates (63.07%) was achieved with the suction-curettage cannula (61.85 +/- 9.03 mg/min to 21.27 +/- 4.42 mg/min (P < 0.001). No severe side effects were observed. CONCLUSION: Due to the higher efficacy we recommend performing suction-curettage with a sharp suction-curettage cannula.

Adult↗
PubMed2006

Increased laser Doppler flow in skin tumors corresponds to elevated vessel density and reactive hyperemia.

BACKGROUND/PURPOSE: Tumor angiogenesis plays a key role in tumor growth and formation of metastasis. Quantitative analysis of tumor blood flow is a prerequisite for developing novel treatment strategies such as antiangiogenic and antivascular treatment options. Laser Doppler flow in malignant melanomas has been shown to be increased compared with normal skin and melanocytic nevi. This study investigated whether this phenomenon is originated by elevated blood vessel density or by reactive hyperemia. METHODS: Laser Doppler flow was studied in 35 melanocytic nevi, 22 malignant melanomas and three basal cell carcinomas. After excision digital imaging analysis was performed in microtome sections (factor VIII-associated antigen and CD 31 labelled). The ratio of vessel area in histological sections from tumor tissue and in non-lesional skin was calculated and related to Doppler flow values. RESULTS: Malignant melanomas demonstrated an enlargement of vessel cross-sectional area by factor 3.7+/-1.9 and of Doppler flow by factor 10.56+/-10.7, and melanocytic nevi accomplished increase of vessel cross-sectional area by factor 1.7+/-0.9 and of Doppler flow by factor 2.7+/-3.5. CONCLUSION: The laser Doppler flow is influenced by the number and the velocity of erythrocytes in the tissue. The greater increase of laser Doppler flow than of vessel density in histological sections demonstrates that the flow signal in skin tumors is caused by neovascularization as well as by functional hyperemia. Laser Doppler perfusion imaging is a useful method for non-invasive, repeated and quantitative assessment of tumor vascular network and effects of antiangiogenic treatment directed vs. tumor vasculature in vivo, but it cannot distinguish between increased vessel density and reactive hyperemia.

Adult↗
PubMed2006

Angiokeratoma circumscriptum arranged in a systematized band-like pattern suggesting mosaicism.

A 10-year-old girl with vascular lesions that had been present since birth is reported. Initially, small red macules were limited to the legs, but later the lesions became more extensive. A hyperkeratotic aspect of the lesional skin surface had developed at the age of 2 years. On clinical examination, hyperkeratotic vascular lesions in a band-like distribution on the trunk, legs and face were observed. The type of lesion varied from discrete macules with no or slight hyperkeratosis to confluent, protruding verrucous plaques. The clinical and histopathological findings were consistent with a diagnosis of angiokeratoma circumscriptum. The systematized band-like arrangement observed in the present case strongly supports the concept that angiokeratoma circumscriptum reflects a mosaic state of a mutation that is so far unknown.

Angiokeratoma↗
PubMed2006

Erbium:YAG laser-assisted preparation of a combined dermal/full thickness sandwich skin graft.

BACKGROUND: Skin grafting is a common procedure to close defects after tumor resection. However, delicate areas such as the heel or the sole of the foot can be closed with a specially designed graft as described in this article. OBJECTIVE: To describe a surgical technique by means of erbium:YAG laser-assisted preparation of a combined dermal/full-thickness sandwich skin graft that facilitates the closure of defects, especially at mechanically stressed anatomic sites. METHODS: Tumor defects on the sole of the foot of 28 patients were closed with a new dermal/full-thickness sandwich skin graft. To obtain this special graft, half of a full-thickness skin graft twice the size of the wound defect was deepithelialized with an erbium:YAG laser. After complete defatting of the transplant, the deepithelialized part was folded beneath the full-thickness part (upside down) resulting in a sandwich graft, enabling contact of the papillary dermis with the wound surface. Graft results were graded as excellent when more than 75%, good if 50-75%, fair if 25-50%, and poor if less than 25% of the transplant healed. RESULTS: Results were graded as excellent in 32%, good in 54%, fair in 11%, and poor in 3% of the patients. Total graft loss was experienced in 1 of 28 patients. Complications such as bulky margins or infection were encountered in 14% of the patients. CONCLUSION: The laser-assisted preparation of the combined dermal/full-thickness sandwich skin graft is a new technique that facilitates the closure of defects in delicate anatomic locations with high mechanical stress like the plantar sole.

Aged↗
PubMed2006

Safety and efficiency of perilesional sclerotherapy in leg ulcer patients with postthrombotic syndrome and/or oral anticoagulation with phenprocoumon.

BACKGROUND: The positive effects of perilesional sclerotherapy for venous leg ulcers is well documented. Although many patients with venous leg ulcers require oral anticoagulation or have had a deep vein thrombosis, the effects of these factors on perilesional sclerotherapy are unknown. The aim of this study was to review effects of oral anticoagulation and/or postthrombotic syndrome on perilesional sclerotherapy. PATIENTS AND METHODS: 28 patients with venous leg ulcers were observed. 12/28 had a postthrombotic syndrome, 5/12 were on oral anticoagulants (phenprocoumon with INR 2-3). During each treatment session, 1 ml sclerosing foam (1:5, polidocanol 2 %, method of Tessari) was injected. Treatment was continued until all extrafascial veins in the 15cm surrounding the ulcer were closed. RESULTS: Closure of the perilesional veins was achieved in all patients with 2.5 +/- 1.8 injections. In 10 of 28 patients (35.7 %), just one injection was needed. More injections were needed, both in patients with postthrombotic syndrome (3.3 +/- 2.1 vs. 1.8 +/- 1.3) and on anticoagulation with phenprocoumon (4.2 +/- 1.2 vs. 2.1 +/- 1.7). There were only two complications: an ascending phlebitis up to the accessory saphenous vein and a superficial erosion at an injection site which healed within 1 week. CONCLUSIONS: Perilesional sclerotherapy with foam is a safe and efficient therapy for patients with chronic venous leg ulcers even with postthrombotic syndrome and/ or ongoing anticoagulation.

Administration, Oral↗
PubMed2005

Acute skin alterations following ultraviolet radiation investigated by optical coherence tomography and histology.

Optical coherence tomography (OCT) appears to be a promising technique to study skin in vivo. As part of an exploratory study to investigate UV induced effects non-invasively we aimed to evaluate the kinetics of acute UVB- as well as UVA1 induced skin alterations by means of OCT, and to correlate the results obtained with routine histology. Twelve healthy subjects received daily 60 J/cm2 of UVA1 and 1.5 minimal erythema doses of UVB on their upper back over three consecutive days. One day (24 h) after the last UV exposure, OCT measurements and skin biopsies were performed in four subjects (day 1) on the centre of the irradiated sites and an adjacent non-irradiated control site. The same procedure was performed in four subjects 3 days and 6 days after irradiation, respectively. Prior to OCT assessment two waterproof marks were drawn on the centre of UVB and UVA1 exposed sites and the control site. The OCT scanner, SkinDex 300, was used in the RI1D measurement modus in order to investigate morphological features, epidermal thickness, and scattering coefficients. Immediately after OCT assessment, 4 mm punch biopsies were taken from the previously marked sites. OCT as well as histological examinations performed on day 1, 3, and 6, revealed markedly higher values for epidermal thickness on UVB exposed skin sites, and slightly increased epidermal thickening in UVA1 exposed sites. UVB exposed sites showed disruption of the entrance signal in the B-scan of OCT resulting in a thickened layer with a signal-poor centre corresponding to hyperkeratosis and parakeratosis as confirmed by routine histology. Surprisingly, the mean scattering coefficients of the epidermis were slightly lower on UVA1 exposed sites, as compared to non-irradiated skin. By contrast, the scattering coefficient of the upper dermis of UVA1 irradiated skin was hardly altered. Moreover, the scattering coefficient of the upper dermis assessed on UVB exposed skin on day 1 was clearly smaller than the scattering coefficient observed on non-irradiated and UVA1 exposed skin. Conclusively, it was possible to demonstrate by means of OCT differences of epidermal thickness and pathological features of the stratum corneum following UV exposure. UVA1 induced epidermal pigmentation as well as UVB induced dermal inflammation may affect the light attenuation in the tissue indicated by a decrease of the scattering coefficient. OCT seems to be a useful tool to monitor UV induced effects in vivo.

Adult↗
PubMed2005

Applications of optical coherence tomography in dermatology.

Histology represents the gold standard for morphological investigation of the skin, though biopsy may alter the original morphology, is non-repeatable on the same site and always requires an iatrogenic trauma. In the past decade, advances in optics, fibre as well as laser technology have enabled the development of a novel non-invasive optical biomedical imaging technique, optical coherence tomography (OCT). The latter is based on a classic optical measurement method known as low-coherence interferometry that enables non-invasive, high resolution, two- or three-dimensional, cross-sectional imaging of microstructural morphology in biological tissue in situ. Using conventional OCT with a lateral resolution of 10-15 microm, the stratum corneum of glabrous skin (palmoplantar), the epidermis and the upper dermis can usually be identified, as well as skin appendages and blood vessels. For example, non-invasive monitoring of cutaneous inflammation, hyperkeratotic conditions and photoadaptive processes is possible by means of OCT. Furthermore, the development of high-output broadband light sources, e.g. femtosecond Ti:sapphire laser, might soon enable ultrahigh image resolutions of about 1 microm in order to investigate skin tissue on the cellular level, which could potentially allow the differentiation between benign and malignant tissues. Beyond a high resolution morphology in OCT images, tissue characterization by additional local physical parameters, such as the scattering coefficient and refractive index may be of great value, in particular in cosmetics and the pharmaceutical industry. Functional OCT imaging based on spectroscopy, tissue birefringence, elastography and Doppler flow reveals further information on tissue properties and represents an important progress of OCT technique in the field of dermatology. Therefore, the advanced versions of OCT technique might not only lead to significant new insights in skin physiology and pathology, but also in diagnosis and therapeutic control of cutaneous disorders with respect to non-invasive diagnosis of conditions and monitoring of disease activity in addition to treatment effects over time.

Humans↗
PubMed2005

Pulsed high-dose corticosteroids combined with low-dose methotrexate in severe localized scleroderma.

OBJECTIVE: To evaluate the efficacy of pulsed high-dose corticosteroids combined with orally administered low-dose methotrexate therapy in patients with severe localized scleroderma (LS). DESIGN: A prospective, nonrandomized, open pilot study. SETTING: Dermatology department at a university hospital in Bochum, Germany. Patients Fifteen patients with histologically confirmed severe LS. Interventions Oral methotrexate (15 mg/wk) combined with pulsed intravenous methylprednisolone (1000 mg for 3 days monthly) for at least 6 months. MAIN OUTCOME MEASURES: Treatment outcome was evaluated by means of a clinical score, 20-MHz ultrasonography, and histopathologic analysis. Safety assessment included the monitoring of adverse effects and clinical laboratory parameters. RESULTS: One patient discontinued therapy. In most of the remaining 14 patients, significant elimination of all signs of active disease (inflammation) and remarkable softening of formerly affected sclerotic skin that resulted in a decrease of the mean +/- SD clinical score from 10.9 +/- 5.3 at the beginning to 5.5 +/- 2.5 at the end of therapy was observed (P < .001). Clinical improvement was confirmed by histologic and ultrasonographic assessments. No serious adverse effects were noted. CONCLUSIONS: These data suggest that pulsed high-dose corticosteroids combined with orally administered low-dose methotrexate therapy is beneficial and safe in the treatment of patients with LS. This treatment regimen should especially be considered for severe forms of LS in which conventional treatments have failed.

Administration, Oral↗
PubMed2005

Erbium:YAG laser treatment of post-burn scars: potentials and limitations.

Erbium:YAG lasers are successfully used to treat a variety of epidermal and dermal lesions, including rhytides, dyschromias, and certain types of scars. To date, however, no report has focused on the experiences with this laser in reconstructive burn surgery. Since 2001, the Erbium:YAG laser has become an integral part of the treatment of postburn scars at the Berlin Burn Center. This paper presents the techniques applied and clinical experiences obtained. In addition, a new stripe technique is introduced, which avoids healing disturbances in scars following deep burns. In conclusion, the Erbium:YAG laser has proven to be a valuable supplementary tool for the improvement of cosmetically disturbing mild postburn scars. It is particularly handy in areas difficult to treat, such as the eyes, nose, lips, and fingers. The individual advantages of the Erbium:YAG laser, other laser systems, and dermabrasion for the treatment of burn scars are compared in a brief survey.

Adolescent↗
PubMed2005

Narrowband UVB phototherapy in skin conditions beyond psoriasis.

BACKGROUND: Narrowband (NB) UVB phototherapy has been proven to be clearly more effective than broadband UVB and safer and/or more practicable than psoralen-UVA in the management of psoriasis. However, the role of NB UVB seems to be less clear in the management of skin conditions beyond psoriasis. OBJECTIVES: We sought to give an update on clinical experiences in NB UVB of nonpsoriatic skin conditions, and to establish its current position within the spectrum of competing photo(chemo)therapeutic options. METHODS: The computerized bibliographic database PubMed, without time limits, and other sources were screened for clinical trials on NB UVB. Included were research articles of randomized controlled trials, open prospective studies, and retrospective observations on NB UVB in skin disorders other than psoriasis. RESULTS: A total of 28 articles met our eligibility criteria including 6 randomized controlled studies, 16 open prospective studies, and 6 retrospective observations. NB UVB is effective in patients with chronic atopic dermatitis (AD) (n = 719) and generalized vitiligo (n = 305) and appears to have some advantages over competing photo(chemo)therapeutic regimens. NB UVB also seems to be effective in patients with polymorphic light eruption (n = 25), early stages of cutaneous T-cell lymphoma (n = 108), chronic urticaria (n = 88), lichen planus (n = 15), pruritus associated with polycythemia vera (n = 10), seborrheic dermatitis (n = 18), actinic prurigo (n = 6), and acquired perforating dermatosis (n = 5). The quality of evidence determined for the aforementioned diagnoses ranged from high to moderate to very low. CONCLUSIONS: The best currently available data on NB UVB in nonpsoriatic conditions exist for AD and generalized vitiligo. In view of its efficacy, benefit/risk profile, and costs, NB UVB may be considered the first-line photo(chemo)therapeutic option for moderately severe AD and widespread vitiligo. In the treatment of most other nonpsoriatic conditions, NB UVB appears to be effective, but current data allow no definitive conclusions as to whether NB UVB should be preferred to competing photo(chemo)therapeutic options such as UVA1 and psoralen-UVA regimens. Because NB UVB may have a wider indication spectrum, including AD, vitiligo, and early-stage T-cell lymphoma, and appears to be equally effective or even more effective than broadband UVB, a switch from broadband UVB to NB UVB seems to be justified.

Dermatitis, Atopic↗