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Biomedical subjects

H Schell

Publications and source records attributed to H Schell.

At least 37 records · Page 2Linked to original sources
PubMed1995

Clinical relevance of sonometry-derived tumour thickness in malignant melanoma--a statistical analysis.

High-frequency sonography has been shown to be a useful tool in planning operative strategy in the surgery of malignant melanoma (MM). The purpose of the present study was to compare sonometric and histometric data of tumour thickness in primary cutaneous MM, applying statistical methods in order to evaluate the pre-operative relevance of sonometry. The thickness of 259 melanomas was measured preoperatively by a 20-MHz B scan, and postoperatively by histometry. Statistical analysis was performed using Pearson's correlation coefficient and absolute and relative differences. Although the correlation between sonometry and histometry was good (r = 0.88), there was a mean difference of 0.39 mm (relative difference 28%). Overall, sonometry was in agreement with the corresponding histological classes in 75% of cases. However, tumours assessed by ultrasound as between 0.55 and 0.95 mm thick were incorrectly classified according to histology in 34%, and those between 1.30 and 1.70 mm were incorrectly classified in 50% of cases. Our data reveal greater differences between sonometry and histometry using appropriate statistical methods. A concept to assess differences between sonometry and histometry is recommended.

Adolescent↗
PubMed1994

[Hair growth promoters in androgenetic alopecia. Expectations and reality].

Androgenetic hair loss is the most frequent reason for the topical application of hair-growth-promoting agents. Such preparations should arrest or even reverse androgen-induced hair follicle regression as well as prolonging the hair cycles, especially of the shortened anagen phase, and thus protect from increased hair loss. True evidence of drug effects on hair growth is problematic, since trichograms, the method chiefly applied by the manufacturers, fail to reveal every factor involved in the follicular activity, especially the duration of anagen stage. For example, an increase in the anagen rate does not always reflect a lengthening of the anagen stage, but may also be due to shortened hair cycles. Accordingly, drug effects on hair growth should be investigated by methods that analyse the cell cycle kinetics. For this approach DNA-flowcytometry of the outer root sheath in plucked anagen hairs and of complete anagen hair bulbs taken by micropreparative techniques from scalp biopsies offers a reproducible method for quick and reliable evaluation of hair growth.

Alopecia↗
PubMed1994

Cell kinetics of anagen scalp hairs under physiological and pathological conditions.

The cell kinetics of anagen scalp hair bulbs taken by punch biopsies from healthy male volunteers (n = 50) were determined at defined bulbar hair segments using microdissection and DNA flow cytometry. The highest proliferative activity (S phase) was measured within the lower most bulbar segment (14.0%) but decreased to the Auber's segment (7.6%) and to the isthmus segment (5.9%). The results support histoautoradiographic data demonstrating most of the proliferative activity in the hair bulb below the Auber's level [1]. Furthermore, cell kinetic data of dissected anagen hair bulbs segmented at Auber's level from an androgen-sensitive scalp area were studied in male pattern baldness (n = 15, Hamilton IV) and hirsutism (n = 13). The results revealed a significant increase of S phase cells in male pattern baldness (8.9%) compared to healthy males (n = 10, 7.9%) as well as in hirsutism (10.2%) compared to healthy females (n = 10, 7.5%). In hirsutism the percentages of S phase cells ran parallel to the plasma levels of dehydroepiandrosterone sulfate whereas no correlation to testosterone could be proved. Similar, 6 hypothyroid and 6 hyperthyroid patients were studied. In hyperthyroidism an increase of S phase values (10.3%) was found, while it decreased in hypothyroidism (6.1%). A correlation between the height of S phase and plasma triiodothyronine level was noted. Our studies demonstrate that DNA flow cytometry is a suitable method for the evaluation of physiological or hormonal influences on cell cycle kinetics of human anagen hair bulbs in vivo.

Alopecia↗
PubMed1993

Sex hormones and antiandrogens influence in vitro growth of dermal papilla cells and outer root sheath keratinocytes of human hair follicles.

Anagen hair bulb papillae, interfollicular dermal fibroblasts, and interfollicular keratinocytes isolated from fronto-parietal scalp biopsies as well as outer root sheath keratinocytes from plucked anagen hairs were separately grown in subculture for 14 d. The effect of different concentrations (2.4 nM-17.3 microM) of testosterone, dihydrotestosterone, and the antiandrogens cyproterone acetate or 17 alpha-propylmesterolone on growth behavior of the mesenchymal and epithelial cell types of the hair follicle were comparatively studied by means of growth curves, cell doubling times, and 3H-thymidine incorporation. For control, all cell lines were subcultured in hormone-free medium. Testosterone and dihydrotestosterone (345 nM) significantly reduced proliferation of papilla cells compared with dermal fibroblasts (p < 0.01) and outer root sheath keratinocytes compared with interfollicular keratinocytes (p < 0.01), as well as compared with cells cultured in control medium. Low concentrations of 17 beta-estradiol were ineffective, whereas doses of 180 nM 17 beta-estradiol increased the growth velocities of all cell types, especially of papilla cells, compared with dermal fibroblasts. Low doses of either cyproterone acetate (24 nM) or 17 alpha-propylmesterolone (29 nM) induced a growth enhancement, especially of papilla cells and outer root sheath keratinocytes, whereas high doses of cyproterone (1.20 microM) and 17 alpha-propylmesterolone (1.45 microM) had opposite effects. These changes were significant between papilla cells and dermal fibroblasts as well as between outer root sheath keratinocytes and interfollicular keratinocytes. Applying increasing doses of androgens to cyproterone acetate (24 nM)- or 17 alpha-propylmesterolone (29 nM)-containing media neutralized the growth-stimulating effect of antiandrogens, particularly in papilla cells and outer root sheath keratinocytes. However, minor differences between testosterone and dihydrotestosterone effects on cell growth were found. The data clearly demonstrate that the changes of in vitro growth of hair follicle cells depend on the concentrations of androgens and antiandrogens, as higher doses of both antiandrogens tested retarded the cell proliferation similar to testosterone or dihydrotestosterone. The papilla cells and outer root sheath keratinocytes reacted more sensitively to the hormones tested, thereby confirming the concept of a distinct androgen sensitivity of these specialized hair follicle cells.

Adult↗
PubMed1993

[Incidence of ocular pigment changes in patients with cutaneous melanoma].

Between October 1990 und April 1992, 116 patients with primary cutaneous melanoma and 6 with primary ocular malignant melanoma underwent both dermatological and ophthalmological examination, standardized personal and clinical criteria being applied. In addition to the record of the DDG melanoma file, the skin type, eye and skin colour, number of naevi, occurrence of any other cutaneous alterations, and the family history with respect to additional malignant neoplasms were documented. It was found that 18/116 patients with cutaneous melanoma also had naevi of the iris, but none had concomitant ocular melanoma. Notably, 32% of first degree relatives (n = 37) had a malignant neoplasm, as against 12% of the dermatological patients with no oncological conditions who acted as controls. Although the occurrence of additional changes in ocular pigmentation alterations in patients with malignant cutaneous melanoma cannot be regarded as significant on the basis of our prospective study, the eye, as a potential location of metastases or the original site in primary malignant melanoma, should be examined during staging and follow-up examinations, especially as isolated cases of oculo-cutaneous correlation have already been reported.

Adult↗
PubMed1992

Distribution of adhesion molecules, IgE, and CD23 in a case of angiolymphoid hyperplasia with eosinophilia.

Angiolymphoid hyperplasia with eosinophilia developed in a 13-year-old boy. The immune phenotype of infiltrating cells and the distribution of adhesion molecules of the integrin, immunoglobulin, and selectin families were analyzed with monoclonal antibodies. The infiltrate consisted mainly of helper lymphocytes, monocytes, eosinophils, CD1+ dendritic cells, and mast cells. A CD23/Fc epsilon receptor was present on 40% of these cells, and surface bound IgE was present on 30% of these cells. The latter was found on all cell types. A cellular adhesion molecule analysis revealed that the proliferating endothelial cells were expressing constitutive ICAM-1, LFA-3, VLA-1, VLA-3, VLA-5, alpha 6, and beta 3-integrin chain as well as activation-dependent VLA-2, VCAM-1, and human lymphocyte antigen-DR. The infiltrating cells expressed LFA-1 and CD2, the correlating ligands for ICAM-1 and LFA-3. Our studies support previous observations of an unusual IgE-mediated immune reaction, and suggest an additional pathogenic role for adhesion events in the development of the pathognomonic cellular composition in angiolymphoid hyperplasia with eosinophilia.

Adolescent↗
PubMed1992

In situ [3H]thymidine labelling of human hair papilla: an in vitro autoradiographic study.

The labelling index (LI) and the location of labelled cells in the papilla of human anagen scalp hair have been studied after in vitro [3H]thymidine (3H-TdR) pulse labelling. Forty-three anagen stage VI papillae from 2 individuals (both females, 25 and 55 years) obtained by micropreparation from deep scalp biopsies were analysed. Labelled cells were found only paraaxially in the basal third of the papilla, i.e. below Auber's line. The 3H-TdR-LI of the papilla cells (0.13 and 0.16%) is about 200-times lower than that of the hair matrix cells below the line of Auber (25.5 and 29.5%). The biological significance of this low proliferation rate in the anagen stage VI hair papilla of healthy human should be defined.

Adult↗
PubMed1991

Growth and cell kinetics of human hair papilla cells in vitro. An autoradiographic and flow cytometric study.

Hair papilla, a distinct specialized dermal compartment, plays a fundamental role in the biology of hair growth. Recently some attention has been focused on hair papilla cells (HPC) as possible targets for drugs influencing the hair growth. Isolation and cultivation of the HPC facilitates screening for such drugs. In the present work, growth and cell kinetics of human occipital scalp follicle HPC have been studied in vitro. HPC grow according to a Gompertz function, i.e. with considerable growth delay long before becoming confluent cultures, due probably to elongation of the potential doubling time (Tpot) and to a parallel increasing cell loss rate. The [3H]dT labelling index of the HPC strongly depends on the age of the subculture; the cycle time being about 4 days. A potential doubling time of about 93 h, indicative of growth fraction (GF) = 1, and a duration of S phase and G2 + M phase of about 8 h each were found by the combined application of continuous labelling with [3H]dT and DNA flow cytometry.

Adult↗
PubMed1991

Cell cycle kinetics of human anagen scalp hair bulbs in thyroid disorders determined by DNA flow cytometry.

In both, 6 hyperthyroid and 6 hypothyroid patients as well as 10 healthy volunteers, cell cycle kinetics of dissected anagen scalp hair bulbs were determined by means of DNA flow cytometry (DNA-FCM). Compared with the healthy control group in patients with thyroid disorders striking differences of cell kinetic data were evaluated. In hyperthyroidism a significant increase (30%) and in hypothyroidism a significant decrease (15%) of S and G2+M phase cell percentages was found. The proliferation index (S+G2+M %) calculated revealed similar results. A correlation between the height of S phase percentages and plasma T3 levels was recognizable but could not be proven statistically. By means of DNA-FCM the study demonstrates for the first time the influence of thyroid hormones on in vivo cell cycle kinetics of human scalp hair bulbs.

Adult↗
PubMed1990

Segmental cell kinetics of the human anagen hair: a DNA-flow cytometric analysis.

The cell kinetics of anagen scalp hair taken by punch biopsies from 70 healthy male volunteers were determined at nine different defined bulbar and follicular hair segments using microdissection and DNA-flow cytometry. The highest mean proliferative activity (S-phase) was measured within the lowermost bulbar segment (14.0%), but decreased to 7.6% at Auber's segment and to 5.9% at the follicle isthmus. Notably, the S-phase data of the upper follicular segments (subdermal 2.4%, infundibular 2.4%) were found to be similar to those of the epidermis (2.5%). This study supporting and supplementing former autoradiographic investigations on human hair matrix epithelium clearly demonstrates the main proliferative activity of the anagen hair follicle being localized in the bulbar segments below Auber's level. Moreover, the method described is well suited for studying the effects of agents influencing cell growth (e.g., hormones or drugs) on the cell kinetics of different anagen hair compartments.

Adult↗
PubMed1990

In vitro effects of testosterone, dihydrotestosterone and estradiol on cell growth of human hair bulb papilla cells and hair root sheath fibroblasts.

The influence of testosterone, dihydrotestosterone (each 10 ng/ml up to 300 ng/ml) and estradiol (0.2 ng/ml up to 10 ng/ml) on the growth behaviour (cell count, [3H]thymidine uptake, cell doubling time) of subcultured human hair bulb papilla cells and hair root sheath fibroblasts was studied. Papilla cells and root sheath fibroblasts were isolated by microdissection from the same anagen hair follicles obtained from biopsies of androgen-sensitive scalp regions in 6 healthy male subjects. Dihydrotestosterone and testosterone concentrations above 30 ng/ml significantly reduced the growth of both cell types; lower doses had no effect. Estradiol had no distinct influence on the growth curves of either cell type up to 10 ng/ml, whereas higher concentrations significantly increased the growth of both cell types as shown by [3H]thymidine uptake. Papilla cells reacted more sensitively than root sheath fibroblast to dihydrotestosterone and testosterone, as shown by the growth curves, [3H]thymidine uptake, and cell doubling time.

Adult↗
PubMed1990

[Paraneoplastic Bazex acrokeratosis--disease course in palliative therapy of cancer of the base of the tongue].

A 62-year old quarryman developed distinct, erythematosquamous and keratotic lesions associated with subungual hyperkeratosis and nail detachment on all fingertips within 9 months. Subsequently, scaly erythema of the nose and of the auricles appeared. Clinically paraneoplastic acrokeratosis Bazex (APB) was diagnosed. Thorough endoscopic examination revealed an asymptomatic squamous cell carcinoma at the base of the tongue, which had already metastasized to the regional lymph nodes. Impressive regression of most of the relevant skin symptoms occurred during combined neck dissection and radiotherapy. A survey of recent reports on APB in the literature is given.

Acrodermatitis↗
PubMed1990

[Objective assessment of therapeutic hair growth--methods, possibilities and problems].

With regard to hair growth induced by therapeutics, we have to consider various aspects of the activity of the hair follicle. This means that a study on the efficacy of hair growth therapeutics requires a selective investigation of different kinds of follicular activity. The decision which of the non-invasive, semi-invasive or invasive techniques available should be applied in a specific case depends on the reliability of the method in relation to the technical requirement, on the one hand, and the acceptance by the volunteer as well as the clinical type and degree of hair loss, on the other. Trichorhizogram results as the only means of evaluating the efficacy of hair growth therapeutics seem problematical, since an increase of the anagen rate does not absolutely correlate with a prolongation of the anagen phase.

Administration, Topical↗