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Biomedical subjects

W Westerhof

Publications and source records attributed to W Westerhof.

At least 109 records · Page 6Linked to original sources
PubMed1987

Controlled double-blind trial of fibrinolysin-desoxyribonuclease (Elase) solution in patients with chronic leg ulcers who are treated before autologous skin grafting.

A controlled, randomized, double-blind trial was performed in 34 hospitalized patients with chronic leg ulcers: 37 ulcerous legs were treated with Elase solution or with saline (placebo) solution. Elase was statistically significantly better in effect on debridement (p less than 0.05) and on enhancing of granulation (p less than 0.05) than saline in patients with chronic venous stasis ulcers. In patients with complex ulcers no statistically significant difference between the two treatments was seen.

Aged↗
PubMed1987

Melanin-related metabolites as markers of the skin pigmentary system.

Three different groups of chemical intermediates are known to be formed during the synthesis of melanin in melanocytes: phenolic compounds, phenolic thio-conjugates, and indolic compounds. All these substances and their metabolites can be detected in urine. We measured the urinary excretion of 3,4-dihydroxyphenylalanine (dopa), 5-S-cysteinyldopa (5-S-CD), and 2 indolic compounds, namely 5-hydroxy-6-methoxyindole (5H6MI) and 5-hydroxy-6-methoxyindole-2-carboxylic acid (5H6MI2C) in urine samples of 4 groups of people with different contents of cutaneous melanin: Asian group, white group, and 2 groups of whites 1 with vitiligo and 1 with tyrosinase-negative oculocutaneous albinism. Dopa and 5-S-CD were determined with the method using high-performance liquid chromatography with an electrochemical detection. Indolic substances were measured by mass fragmentography with deuterium-labeled internal standards. Comparison of the melanin-related metabolites excreted in urine of people with different capacities for melanin biosynthesis indicates that, of all measured substances, 5H6MI2C is the best urinary marker of melanin formation in the skin pigmentary system.

Adolescent↗
PubMed1987

The morphology of keratohyalin granules in orthokeratotic and parakeratotic skin and oral mucosa.

We compared morphologic features of keratohyalin granules (KHG) that were directly related to keratinization in oral mucosa (tongue, cheek, gums, palate; n = 4) with those in parakeratotic epidermis (psoriasis, n = 2; pityriasis rubra pilaris, n = 1; acute dermatitis, n = 1) and normal orthokeratotic epidermis. Among others, the ultrastructural features of globular KHG were observed in the cheek, nonspecialized tongue mucosa, and parakeratotic epidermis occurring in psoriasis, pityriasis rubra pilaris, and acute dermatitis, whereas gums and palate showed a mixture of characteristics, also resembling stellate KHG as seen in normal skin. From literature as well as from our studies, the impression was gained that globular KHG were found especially in quickly dividing epithelia and could easily be distinguished from the irregular or stellate KHG that were found in slowly dividing normal epidermis. Therefore, we studied keratinization features on days 3, 7, and 14 after autografting normal human skin (n = 4), thus inducing high cell turnover. Stellate KHG, present in granular cells of normal skin, were almost absent on the third day. Active cell division on the seventh day resulted in sparse keratohyalin formation inside globular granules of low electron density, whereas numerous, rather electron-translucent lipid droplets occurred in upper spinous and horny cells. These two phenomena seemed to be interrelated. After 14 days, round and increasingly electron-dense KHG were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytoplasmic Granules↗
PubMed1986

Hypertelorism in neurofibromatosis.

In eight out of thirty-four patients with neurofibromatosis hypertelorism was seen. This hypertelorism was diagnosed by measuring the intercanthal distance and calculating the interpupillary distance from it. The high incidence of hypertelorism in our group of patients (24%) makes its direct association with neurofibromatosis feasible. Moreover, hypertelorism was found exclusively in neurofibromatosis patients with brain involvement (8 out 11) and therefore seems to herald a severe expression of Morbus Recklinghausen. The bones of the face and the base of the skull are mesenchymal structures of neural crest origin and skull dysplasias - e.g. hypertelorism - fit well into the neurocristopathy concept of neurofibromatosis. Its ease of clinical recognition and its presence at birth makes the hypertelorism an early diagnostic criterium.

Adolescent↗
PubMed1986

The morphological details of globular keratohyalin granules.

In quickly dividing epithelia such as that of the tongue, keratohyalin formation takes place in globular keratohyalin granules (KHG). This is in contrast with the irregular KHG as seen in normal, slowly dividing epidermis. The morphogenesis of the globular KHG is explained in this study. In small KHG, dense aggregates of ribosomes can be seen at the site of blebs. It is suggested that these blebs framed with ribosomes are internalized giving rise to "dense homogeneous deposits" or "single granules". Lipid droplets occur in the upper spinous and horny layer. Globular KHG also contain variable amounts of lipids, and the lipid content seems to be inversely related to the protein content, dependent on the degree of cell differentiation or on the rate of cell turnover. It is suggested that in epithelia with a high cell turnover few rigid keratohyalin components are dispersed in lipids, which maintain a globular shape due to the surface tension.

Cheek↗
PubMed1986

Langerhans' cell population studies with OKT6 and HLA-DR monoclonal antibodies in vitiligo patients treated with oral phenylalanine loading and UVA irradiation.

In vitiligo patients, treated with oral phenylalanine loading combined with UVA irradiation (Phe-UVA), Langerhans' cells (LC) were counted in pigmented and depigmented skin. The LC, which were labelled with OKT6 and HLA-DR monoclonal antibodies, were expressed per linear mm epidermis. Before treatment the number of OKT6(+) cells was significantly increased in vitiliginous skin especially in the basal layer. Under treatment the number went down and was comparable to normal skin. When using HLA-DR labelling the number of LC increased in vitiliginous skin which had been treated with Phe-UVA. The influence of Phe-UVA on the shift of LC subpopulations is discussed.

Adult↗
PubMed1986

Quantification of UV-induced erythema with a portable computer controlled chromameter.

A sensitive computer controlled tristimulus color analyzer (Minolta Chromameter II Reflectance) was used to measure UV-induced erythema quantitatively. Of the 5 available chromaticity measuring modes in the instrument, one of the values (a*) was enough to specify the erythema quickly. A comparison has been made between results using the instrument and a graded score based on visual perception of erythema. This easy to operate instrument is suitable for both clinical and field conditions.

Adult↗
PubMed1985

Phenylalanine and UVA light for the treatment of vitiligo.

The administration of phenylalanine (Phe) combined with UVA exposure was found to be effective in vitiligo. Phe is an amino acid which constitutes part of the daily dietary protein, and when orally administered in a dose of 50 mg/kg body weight, it results in an elevated plasma level. Since peak concentrations of Phe in the blood are reached between 30 and 45 min after ingestion, UVA exposure was administered at this time. After 4 months (32 treatments) reasonable repigmentation preferentially occurred in the skin area of subcutaneous fat (adipose tissue). Apart from the repigmentation of hypo-pigmented macules, vitiligo patients can tolerate more sun than usual, especially at the vitiliginous lesion, and they experience no sunburn as a result of Phe-UVA therapy. Normal skin also tans very well.

Adolescent↗
PubMed1985

Possibilities of liposomes as dynamic dosage form in dermatology.

Local application of substances in different vehicles for the care of the skin and the treatment of skin diseases have been used since antiquity. With the present state of technology a modern dosage form allowing chemical engineering can be devised. Liposomes which consist of lipid bilayers engulfing an aqueous solution fulfill the sophisticated requirements. With a lipid and an aqueous compartment these liposomes can contain lipophilic and hydrophilic medicaments. The lipid composition and the incorporation of charged carrier protein molecules can be varied, affecting the rate of drug release to the skin. In this way active substances are either retained on the skin (pertinent to sunscreening agents) or liberated from the liposome depot to the skin layers (corticosteroids). The highly organized membrane structures containing lysine or hydrolysine can be fixed to the skin enzymatically avoiding temporal removal from the skin and supporting depot function and protective film function. Studying the surface lipid and epidermal lipid composition, lipid membranes can be composed which do not cause hypersensitivity reactions and form a substitute in case of deficient barrier function of the skin.

Dermatologic Agents↗
PubMed1985

Comparison of bioavailability and phototoxicity of two oral preparations of 5-methoxypsoralen.

5-Methoxypsoralen (5-MOP) (Psoraderm 5) tablets obtained from France and 5-MOP micronized in capsules (manufactured in our pharmacy department) were administered to seven psoriasis patients in a 1.2 mg/kg body weight dose schedule. Bioavailability and phototoxicity were compared. It was found that the maximum serum concentration and the area under the concentration curve were significantly higher (P less than 0.01) after administration of the capsules, indicating higher bioavailability. No erythema developed in any of the patients after administration of the tablets, whereas with the capsules four of the patients developed erythema at the test site. The absence of erythema following the use of the tablets is probably due to the poor bioavailability of this preparation.

5-Methoxypsoralen↗
PubMed1984

[Vitiligo].

Explore the source record for details and available documents.

Administration, Topical↗
PubMed1984

Neurofibromatosis and hypertelorism.

Hypertelorism was observed in eight of 34 patients with neurofibromatosis. This diagnosis was made by measuring the intercanthal distance and calculating the interpupillary distance from it. The bones of the base of the skull and of the face are mesenchymal structures of neural crest origin. Skull dysplasias, in which hypertelorism can be included, fit well into the neurocristopathy concept of neurofibromatosis. Hypertelorism seems to herald a severe expression of neurofibromatosis, eg, with brain involvement, and would therefore be an indication for doing a computed tomographic scan. The high prevalence of hypertelorism in our group of patients (24%) makes its direct association with neurofibromatosis highly feasible. Its ease of clinical recognition and its presence at birth would make it a valuable early diagnostic criterion.

Adolescent↗
PubMed1983

Albinism: phenotype or genotype?

As part of a combined ophthalmological, genetic, clinical, biochemical, ultrastructural and electro-physiological study of albinism we have examined over one hundred albinos, together with their heterozygote family members. Given this substantial number, we have developed a diagnostic protocol to facilitate albino classification and heterozygote detection. The major difficulty in the detection and differential diagnosis of albinism is that for a given albino, not all symptoms, either ophthalmological or cutaneous, may be manifest, whereas several may be in a non-albino. To compensate for the wide diversity in albino expression, diagnosis is typically based on the results of combinations of tests.

Adolescent↗