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Biomedical subjects

D van Neste

Publications and source records attributed to D van Neste.

9 recordsLinked to original sources

Dermal objective pharmacodynamic profile of cetirizine and epinastine: two controlled, randomised, double-blind, crossover studies.

Two double-blind clinical pharmacology studies were performed in healthy volunteers to compare the dermal pharmacodynamic profile of epinastine with cetirizine, a well-documented anti-H1 antagonist, after oral administration at the usual recommended dosage, i.e. 10 mg cetirizine and 20 mg epinastine (versus placebo). Histamine skin challenges (prick test) were evaluated before and at 1, 2, 4, 8 and 24 hr after drug intake by measuring the wheal and flare area (studies 1 and 2) along with laser Doppler monitoring of the microvascular responses (study 2). A decrease in wheal and flare areas was observed following intake of both drugs compared with placebo controls. With the notable exception of 1 hr post dose wheal values, which were consistently smaller after epinastine, cetirizine was superior to epinastine for both wheal and flare at all other times. At the prick test site, treatment with epinastine and cetirizine accentuated the increase in blood flow induced by histamine. This reflects the decrease of the whealing but there was no significant difference between the two active test compounds. At 1 cm from the prick test site, the administration of both active treatments inhibited the increase of blood flow, and cetirizine showed a more potent inhibitory effect from 8 hr post dose. This reflects the reduction of the flare induced after histamine-receptor activation of the axon reflex. In conclusion, epinastine shows a rapidly greater (within 1 hr post dose on the wheal only) but vanishing effect than cetirizine. At all other time points, cetirizine was generally more effective than epinastine.

Administration, Oral↗

A new case of isolated trichothiodystrophy.

We describe a new case of isolated trichothiodystrophy. This entity is characterized by sparse and brittle hair, low sulfur hair content, tiger tail pattern of the hair under polarizing microscopy, clean transverse fractures through the hair shaft and absent or defective hair cuticles. To our knowledge there are only two reported cases of isolated trichothiodystrophy without associated additional ectodermal or neuroectodermal dysplasias. Polarized microscopy of cut hair showed transverse fracture points (trichoschisis) and alternating dark and bright bands. Low sulfur content of the hairs was confirmed by amino acid analysis. Many acronyms and eponyms have been created to describe sulfur-deficient brittle hair associated with neuroectodermal abnormalities, leading to confusion. We suggest to use a simple classification scheme, according to increasing severity of associated features as proposed by Van Neste.

Child, Preschool↗

Monitoring of skin response to sodium lauryl sulphate: clinical scores versus bioengineering methods.

The present trial was designed to evaluate clinical scores (single observer) of sodium lauryl sulphate (SLS)-induced skin irritation in a group of subjects (n = 10) over a 10-day period along with various skin function parameters. In order to avoid significant variations due to secondary phenomena, the following parameters were recorded with non-invasive instruments in this order: skin capacitance (C1; arbitrary units; CM420 Corneometer), transepidermal water loss (TEWL; g/m2.h; Evaporimeter) and laser Doppler flowmetry (CBFV: cutaneous blood flow values; Periflux). All examinations were performed during winter on reclined relaxed subjects present for at least 10 min in a test room with controlled temperature and relative humidity (t degrees: 19.5-20.7 degrees C and RH: 47.3-60.3%). The analysis of differential data (delta = value at tx-value before test; 2-way ANOVA) was made on single parameters as a function of site (volar forearm versus neck) and time (from 24 h after 48-h occlusion with 5% SLS up to 10 days later). The profile of erythema scores over time differed between neck and forearm, but the delta CBFV readings with the laser Doppler instrument did not detect significant site-time interactions. Roughness (blind evaluation with palpating finger) and capacitance readings (delta C1) showed significant differences between sites, but the profile over time was similar in both locations. delta TEWL did not differ according to anatomical location. The reason for different erythema scores on neck and forearm might be related to inherent regional variation of optical properties of the skin or to a substantial contribution of SLS-induced roughness to the readings of erythema.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

In vivo evaluation of unbound water accumulation in stratum corneum. The influence of acute skin irritation induced by sodium laurylsulfate.

In a series of previous experiments, we showed that the inflammatory response associated with skin barrier function damage induced by sodium laurylsulfate (SLS) was correlated with the concentration of SLS and with the duration of application under occlusion of the surfactant. In this experiment, we measured accumulation of unbound water that occurred when occlusive contact was maintained during a short period of time between the skin and the probe head of an electrometric device. Accumulation of unbound water was expressed as area under the curve (sum of increments of skin capacitance during a 45-second period of time; AUCC). For comparative purposes, we also measured transepidermal water loss (TEWL). Both skin function parameters were established for each individual skin site before and 24 h after removal of SLS patches (10, 5, 1 and 0% control solution under occlusion for 48 h). After SLS insult, AUCC and TEWL were increased, and changes were related to SLS concentration (p less than 0.0002). There was a linear correlation between AUCC and log TEWL (p less than 0.0002). On normal skin before application of SLS both parameters were also correlated (p less than 0.04). The regression line between AUCC and log TEWL of normal skin differed however from that observed on SLS-pretreated sites. This indicates that electrometric data are able to simultaneously characterize changes in skin hydration, a rather static parameter, and changes in the amount of unbound water accumulation (AUCC), a dynamic parameter which proved to reflect TEWL.

Acute Disease↗

Epidermal changes in atopic dermatitis.

The epidermal changes occurring in various lesions of atopic dermatitis are reported. Quantitative evaluation or epidermal thickening suggests that both differentiated and undifferentiated compartments are increased in lichenified lesions. In dry skin (xerosis) of atopic dermatitis moderate but obvious inflammatory changes are observed. There is a mild increase of the epidermal volume without folding of the dermo-epidermal interface. The latter is most prominent in exudative and lichenified lesions where a fourfold overall increase of epidermal volume is observed.

Biopsy↗

Histological assessment of skin damage by irritants: its possible use in the evaluation of a 'barrier cream'.

The histological changes induced by topical application of selected irritants are reported. The possible application of this methodology to the evaluation of the protective value of a silicone-containing barrier cream is discussed. Although this crude method only allows objectivity of the later stages of a toxic reaction, it gives useful information about the potential protective effect of a silicone-containing barrier cream.

Animals↗

A new way to evaluate the germinative compartment in human epidermis, using [3H]thymidine incorporation and immunoperoxidase staining of 67 K polypeptide.

We have used tritiated thymidine (3HT) labelling and immunoperoxidase staining of 67 K polypeptide in human epidermis to study normal skin before and after irritation induced by application of croton oil (20% and 50% in olive oil). By this double labelling method, it was possible to identify, on the same skin section, DNA-synthesizing nuclei and epidermal cells which contained 67 K polypeptide. Our results clearly indicate that the germinative compartment of normal epidermis is a mixed population comprising basal and adjacent suprabasal cells; as a rule, absence of expression of 67 K polypeptide, which characterizes all basal cells, could not be regarded as a good marker to distinguish the germinative from the differentiating compartments. In mild primary irritation, the ratio of 3HT-labelled undifferentiated cells to keratinizing ones was similar to that observed in normal epidermis. In severe irritation, this homeostatic process was altered, as 3HT-labelled cells were mainly 67 K negative.

Aged↗