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Biomedical subjects

M Heenen

Publications and source records attributed to M Heenen.

At least 73 records · Page 4Linked to original sources
PubMed1997

A case of pyoderma gangrenosum stabilized with lymecycline, topical benzoyl peroxide and treated by autograft.

Pyoderma gangrenosum is a chronic inflammatory ulcerative skin disease of unknown etiology, often associated with various systemic disorders such as inflammatory bowel disease, rheumatoid arthritis, chronic active hepatitis, diabetes mellitus and hematologic malignancies. The ulcers are characterized by their undermined violaceous borders. The disease remains a therapeutic challenge. Corticosteroids are the mainstay of therapy; however, side effects from this treatment and recalcitrant pyoderma gangrenosum require therapeutic alternatives. We report the case of a large subacute pyoderma gangrenosum stabilized with lymecycline, topical benzoyl peroxide and successfully treated by an autograft. This observation supports the opinion that the risk of pathergy of a graft can be avoided by the stabilization of the disease.

Acute Disease↗
PubMed1997

The growth fraction of normal human epidermis.

In human epidermis, germinative cell production is determined by three parameters: the cell cycle time, the loss of cycling cells by programmed cell death and the proportion of keratinocytes actively engaged in the cell cycle or growth fraction. The last parameter is still a subject of debate as the identification of a proliferative cell with certainty is impossible. Two indirect methods (grain count dilution of labelled cells and continuous labelling) suggest that non-proliferative cells may exist in the germinative compartment of human epidermis. Results obtained in vitro demonstrate that keratinocytes can be blocked in certain conditions in a state of quiescence similar to a G0 phase. Increasing evidence suggests that, as in mouse epidermis, the germinative compartment of human epidermis is and is divided into a small proportion of stem cells (10%) with a high proliferative potential, a larger proportion of transit-amplifying cells with a limited proliferative potential (50%) and postmitotic cells committed to undergo terminal differentiation (40%). In this hierarchical arrangement, most of the nonproliferative cells belong to the postmitotic compartment. If this model is correct, the germinative cell population in a quiescent or G0 state is a small proportion of the stem cell compartment and has therefore little influence on the kinetics of normal human epidermis.

Cell Division↗
PubMed1997

Overlap of sarcoidosis and rosacea.

Numerous descriptions have been applied to rosacea-like eruptions of the face, some of them remaining of questionable nosologic significance. A case of rosacea-like syndrome with lacrimal, ocular and salivary involvement is described. The differential diagnosis and therapeutic response of this unusual association are discussed.

Adult↗
PubMed1997

[Cell cycle: regulation and abnormalities in epidermal tumors].

The size of a tissue such as the epidermis, and its potential growth, results from the balance between cell production and loss. The mechanisms controlling these two parameters are still poorly understood. Major advances have however been recently achieved in our knowledge of cell cycle regulation and programmed cell death. Dysregulation could explain the development of neoplastic tumors. Basal cell carcinoma basically results from a fall in programmed cell death. Spindle cell carcinoma results from an increased cell production. Both mechanisms are involved in melanoma. One must however keep in mind the fact that we are dealing with hypotheses which remain to be verified.

Basal Cell Carcinoma↗
PubMed1996

Decreased skin reactivity to codeine in patients with the acquired immunodeficiency syndrome.

To evaluate the skin reactivity and the mast cell releasibility in the acquired immunodeficiency syndrome (AIDS), 24 patients with AIDS were skin tested with histamine (1 mg/ml) and codeine phosphate (0.9, 0.09, and 0.009 mg/ml), a mast cell degranulating agent. They were compared to 12 HIV-negative healthy volunteers and 16 urticaria-prone subjects. Reactivity to codeine phosphate was lower in patients with AIDS than in HIV-negative subjects. This difference in skin reactivity was the more significant when the AIDS group was compared to the urticaria-prone group. There was no correlation between the reactivity to codeine and the IgE levels. Possible explanations to the decreased skin reacting to codeine in patients with AIDS include a decrease of local mast cell density or releasibility. This suggests that a mechanism related to urticaria and involving mast cells is quite unlikely to be at the origin of the hypersensitivity reactions observed in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1996

p53 Protein overexpression in verrucous carcinoma of the skin.

BACKGROUND: Verrucous carcinoma is a rare variant of well-differentiated squamous cell carcinoma which is characterized by a marked local aggressivity and a poor metastatic potential. Until now, little has been known about the oncogenic mechanisms of this tumor. Recently, extensive investigations have shown that p53 protein, a nuclear protein with oncogene-suppressing activity, may play a crucial role in cell transformation and immunoreactivity for this protein is found in a wide variety of cancers. OBJECTIVE AND METHODS: The aim of the present study is to examine the frequency of immunohistochemically detectable p53 protein by using two monoclonal antibodies (D07 and BP53-12) in 8 cases of formalin-fixed and paraffin-embedded specimens of verrucous skin carcinoma. RESULTS: Overexpression of p53 protein was detected in 6 (75%) of the cases examined with the D07 antibody and in 5 (62.5%) cases with BP53-12. The p53 positivity was shown in a peripheral distribution affecting mainly the basal cell layers of tumoral islands. CONCLUSION: In a high percentage of verrucous carcinoma, p53 immunoreactivity has not been previously described in the literature and our findings suggest that abnormal expression of p53 tumor suppressor protein is a common event in the pathogenesis of this tumor.

Aged↗
PubMed1995

[Systemic sarcoidosis with cutaneous lesions: literature review].

Sarcoidosis is a systemic disease of unknown etiology. The diagnosis is based on consistent clinical, biological and radiological findings supported by histologic evidence of noncaseating epithelioid granulomas. Skin lesions occur in about a quarter of patients with sarcoidosis. The purpose of this article is to analyse through the clinical presentation of dermatological lesions, a potential link with systemic disease.

Adolescent↗
PubMed1995

Proliferating cell nuclear antigen distribution in verrucous carcinoma of the skin.

Verrucous carcinoma (VC) of the skin is a rare variety of well-differentiated squamous cell carcinoma (SCC) characterized by aggressive local growth and a low metastatic potential. These tumours are known to have histological and virological features similar to classic warts or condylomata. The aim of the present study was to map the proliferative compartment in VC (n = 7) in comparison with warts (n = 10) and typical well-differentiated SCC (n = 10). The proliferating cells were detected by immunostaining of proliferating cell nuclear antigen (PCNA) in formalin-fixed, paraffin-embedded tissue sections, using the commercially available anti-PCNA monoclonal antibody PC10. Normal epidermis served as a positive control and reference. In VC and warts, the PCNA-positive cells were principally located at the periphery of lesions, in the basal layer of the tumour islands. In some warts, however, stronger PCNA expressed was noted in the superficial layers, of the lesions corresponding to virus-infected keratinocytes (koilocytotic cells). In contrast, in SCC, PCNA-positive cells were randomly scattered throughout the tumours. Our findings suggest that, on the basis of mapping of PCNA distribution, VC resembles large warts or condylomata rather than typical SCC. Thus, VC appears to be a distinct clinical entity, intermediate between these two types of lesions, not only because of its clinical entity, intermediate between these two types of lesions, not only because of its clinical and virological features, but also with regard to its proliferative organization.

Carcinoma, Squamous Cell↗
PubMed1994

FB1, a monoclonal antibody reacting with a keratin 14 epitope, stains only a small subset of psoriatic basal keratinocytes.

A murine monoclonal antibody, FB1, reacted with the basal keratinocytes of human stratified epithelia. One-dimensional and two-dimensional immunoblotting assays, performed on keratins extracted from HaCat cells and normal human keratinocytes, showed that FB1 recognizes K14. When LL002, another K14 monoclonal antibody is added, the FB1 stained area in the 2D-immunoblot seems to cover a fraction of the LL002 spot. Immunohistochemical data obtained from studies on normal human tissues supported the K14 specificity of FB1, but when compared with two other monoclonal antibodies, LL002 and RCK107 reacting with K14, some differences appeared. These differences were mainly seen in sweat glands, hair follicles, psoriatic epidermis and salivary glands. In psoriatic epidermis, FB1 showed a heterogeneous pattern of staining of the basal cell compartment. Intense reactivity was only observed at the bottom of the rete ridges. Staining diminished and finally disappeared in the basal cells above the dermal papillae. This observation supports the view that an increased germinative cell population in psoriasis involves a partially differentiated amplifying compartment in which the number of cell divisions is increased.

Animals↗
PubMed1994

Transformation of common warts into squamous cell carcinoma on sun-exposed areas in an immunosuppressed patient.

We report one case of renal transplant recipient who developed widespread multiple verrucous skin lesions. Histologic examination revealed typical warts and, only from several sites exposed to sun (hands and face), a development of dysplasia within the warts and a transformation of some of them toward infiltrating squamous cell carcinoma (SCC). Human papillomavirus (HPV) testing for DNA by polymerase chain reaction DNA amplification identified HPV type 1 in both warts and SCC. Our findings suggest that classic warts may progress to high-grade lesions and that, in addition to the oncogenic potential of the virus alone, other factors including the host's immunosuppressed state and ultraviolet radiation seem to be essential to malignant transformation.

Adult↗
PubMed1994

The heterogeneity of the germinative compartment in human epidermis and its implications in pathogenesis.

In mouse epidermis keratinocytes of the basal layer seem to belong to 3 different subpopulations: stem cells, transit cells and postmitotic cells. Each subpopulation assumes a specific role in epidermal homeostasis. Recent data tend to display a similar heterogeneity among basal keratinocytes in human epidermis. This concept opens the door to an integrated understanding of epidermal renewal but also suggests new hypotheses in pathogenesis. Psoriasis, a typical example of epidermal hyperplasia, is considered from this point of view.

Animals↗
PubMed1994

Clinical experience with short schedules of itraconazole in the treatment of tinea corporis and/or tinea cruris.

BACKGROUND: Superficial fungal infections have usually been considered to be caused only by dermatophytes. In recent years their epidemiology has been changing with other fungi being isolated and, thus, antifungal agents with a broad spectrum of activity, such as itraconazole, may be particularly useful. The risk/benefit ratio for any such treatment is determined by its tolerability profile and the duration of therapy. OBJECTIVE: The aim was to compare the efficacy and tolerance of a shorter treatment regimen, using a higher dose of itraconazole, with a standard itraconazole regimen in the treatment of tinea corporis/cruris. METHODS: An open study compared oral itraconazole 200 mg daily for 7 days with oral itraconazole 100 mg for 15 days in 153 patients with tinea corporis/cruris. RESULTS: At follow-up all patients in both groups were clinically cured or markedly improved. However, mycological cures were greater in the 7-day treatment group (90%), and the onset of clinical and mycological cure was faster in this group. CONCLUSIONS: Itraconazole, 200 mg daily for 7 days, offers a short convenient and effective treatment option for tinea corporis and tinea cruris.

Administration, Oral↗