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Biomedical subjects

E Berardesca

Publications and source records attributed to E Berardesca.

At least 73 records · Page 4Linked to original sources
PubMed1989

Changes in the water holding capacity of psoriatic stratum corneum in vivo.

This study investigated the functional capacity of the stratum corneum of psoriatic skin to bind water in vivo during a relatively long period of time (water holding capacity--WHC). An electrical capacitance test was applied to the psoriatic skin on the elbows, perilesional skin and apparently normal skin of 11 patients and the elbows of 10 controls. Measurements of electrical capacitance were performed using a Corneometer Schwarzhaupt for 25 min. The WHC levels were calculated for this period. Our results demonstrate that the WHC of psoriatic stratum corneum does not differ from controls in the first 10 min. Only after the 20th min do the WHCs differ significantly (p less than 0.02). Despite the biochemical keratin changes in psoriatic plaque, the latter is highly hygroscopic, in particular in the first minute after bathing. Perilesional skin binds water like the stratum corneum of controls, though not beyond the 20th minute after bathing.

Adult↗
PubMed1989

[Changes in the biomechanic property of the skin after hemodialysis treatment].

Skin extensibility in 21 subjects (belonging to two different age groups) undergoing hemodialysis has been investigated. Measurements have been performed on the forearm before and after two hours of dialytic treatment. A significant decrease of skin extensibility (P less than 0.02) has been recorded in the elderly prior to the dialytic procedure; the data is consistent with an increased dermal water content. Water removal during treatment led to normalization of extensometric levels (P less than 0.05). However, improvement of skin extensibility is not directly related to the amount of water withdrawn. The study support the importance of water in determining skin viscoelastic responses; hemodialysis is a useful model to monitor the effects of water on skin biomechanics.

Age Factors↗
PubMed1988

In vitro transepidermal water loss: differences between black and white human skin.

In vivo transepidermal water loss studies are characterized by large inter-individual variability and biased by environmental effects and eccrine sweating. An in vitro technique for measuring transepidermal water loss (TEWL) was used to compare TEWL in two racial groups--blacks and whites. In both groups a significant correlation between skin temperature and increased TEWL was found (P less than 0.01). Furthermore, black skin had a significantly higher mean TEWL than white skin, corrected log TEWL 2.79 and 2.61 micrograms/cm2/h, respectively. The difference in TEWL between the groups could because measurements were made in the absence of eccrine sweating and other vital functions. The higher TEWL in black skin could be explained on the basis of a thermoregulatory mechanism. The anatomical and physiological differences in the stratum corneum between different races are discussed.

Adolescent↗
PubMed1988

Racial differences in sodium lauryl sulphate induced cutaneous irritation: black and white.

The different reactivity of black and white skin after exposure to sodium lauryl sulphate (SLS) has been investigated. 9 white and 10 black male volunteers entered the study. The tests were performed on the back at 3 sites: untreated skin, skin pre-treated with occlusion and skin pre-delipidized. Irritant reactions were elicited applying 0.5% and 2.0% SLS via Finn chamber patch tests and monitored by means of laser Doppler velocimetry (LDV), transepidermal water loss (TEWL) and stratum corneum water content (WC). Higher TEWL, LDV, and WC values were recorded for 2.0% SLS when compared to 0.5% SLS and baselines. Pre-treatment with short-term occlusion generally increased values, while delipidization produced flattening of the data more detectable in whites than in blacks. Significant TEWL differences for the two concentrations were recorded in whites for the occluded site (P less than 0.02) while in blacks in the untreated (P less than 0.04) and delipidized (P less than 0.03) sites. LDV revealed significant changes in the untreated and pre-occluded white skin (P less than 0.05 and 0.01, respectively). In blacks, the values were significantly different only in the pre-occluded skin (P less than 0.01). Water content correlated with the visual score and was greatly increased in sites with strongly positive reactions (P less than 0.01). It appears that there are significant differences in the modulation of irritation, in the behavior of water barrier function and of the erythematous response between blacks and whites. Clinical correlations are discussed.

Adult↗
PubMed1988

Bioengineering and the patch test.

Several non-invasive techniques based on different physical principles have been developed to investigate skin function and have been used for patch test assessment. In the present paper, the advantages and the defects of these methods are described in the light of the more recent data available in literature. Meanwhile, the eye and the fingers still remain the simplest method to assess skin irritancy. Bioengineering techniques could provide efficient recording systems for monitoring skin color, skin blood flow and barrier function damage, useful to the investigator rather than to the clinician.

Colorimetry↗
PubMed1988

Sodium-lauryl-sulphate-induced cutaneous irritation. Comparison of white and Hispanic subjects.

Reactivity of white and hispanic skin after exposure to sodium lauryl sulphate (SLS) has been investigated. The tests were performed on the back as follows: untreated skin, skin pre-treated with short-term occlusion and delipidized skin. Irritant reactions were induced by applying 0.5% and 2.0% SLS via Finn chamber patch tests and monitored by means of laser Doppler velocimetry (LDV), transepidermal water loss (TEWL) and stratum corneum water content (WC). Higher TEWL, LDV and WC were recorded for 2.0% SLS when compared to 0.5% SLS and baselines. Differences between white and hispanic skin reactivity were recorded. TEWL and WC responses showed a greater sensitivity in hispanics possibly reflecting a different modulation of the water barrier function after chemical exposure. On the other hand, the microcirculatory response, as long as detected with LDV, was similar in the 2 groups. Correlations between these data and findings observed in other races are discussed.

Adult↗
PubMed1988

Skin occlusion: treatment or drug-like device?

The effects of occlusion on skin function are described and reviewed. Occlusion seems to be not only a device applied on the skin surface, but, under certain conditions, a powerful treatment capable of inducing several changes on epidermal metabolism, skin flora, sweat glands and epidermal morphology.

Animals↗
PubMed1988

Topical spironolactone inhibits dihydrotestosterone receptors in human sebaceous glands: an autoradiographic study in subjects with acne vulgaris.

The interaction between spironolactone and dihydrotestosterone (DHT) receptors was evaluated with an autoradiographic technique. The inhibition of DHT receptors by spironolactone was found to be related to the decrease of tritiated DHT granules in the sebaceous glands of the treated site. 6 male patients affected by acne vulgaris entered the study. The acute study was performed by applying to 25 cm2 of the back a cream containing 5% spironolactone under occlusive dressing. The dosage of spironolactone applied was 4 mg/cm2 for 48 h. The long-term study was performed by applying the same amount to the entire back, without occlusion, twice daily for 1 month. Skin biopsies were taken at the end of the treatment, incubated with tritiated DHT and processed for autoradiography. Both the acute and the long-term study revealed a decrease of the autoradiographic granules in the treated site. This effect is related to the binding of spironolactone with dihydrotestosterone receptors in the sebaceous glands. Our study demonstrates that 5% topical spironolactone cream acts as an antiandrogen in human sebaceous glands, competing with DHT receptors and producing a decrease of labelled DHT. At the concentrations used the effect has been only local. No side-effects were recorded during both studies.

Acne Vulgaris↗
PubMed1988

Contact dermatitis in blacks.

Black skin is characterized by structural and functional differences such as increased stratum corneum cohesion, melanin content, and stratum corneum layers. These differences seem to make black skin difficult for irritants and light to penetrate, thus explaining the common opinion that skin in blacks is harder and develops contact dermatitis less frequently. The paucity of interpretable epidemiologic data and of clinical and experimental studies does not permit confirmation of this hypothesis, and the few data available are controversial. This article describes the main physiologic differences between black and white barrier function and reviews the literature on irritation, sensitization, and transcutaneous penetration. We found that the data are still too incomplete to generalize on the resistance, or lack thereof, of black skin (versus white skin) to chemical irritation, sensitization, and penetration.

Black People↗
PubMed1988

Assessment of the effects of a topical product containing glycosaminoglycans in cutaneous hydration.

The hydrating power of a topically applied mixture of glycosaminoglycans has been evaluated by means of an electrical impedance method. The electrical parameters investigated, namely angle alpha and R infinity, are related to the permeability and the hydration of deeper tissues. The study revealed lowering of alpha levels after the application of the product, thus signifying an accumulation of electrical charges in the epidermis consistent with the penetration of glycosaminoglycans. After 15 days of treatment, significant reduction of R infinity levels was recorded. The relationship between R infinity levels, dermal water content and glycosaminoglycans is discussed.

Administration, Topical↗
PubMed1988

Normal sensitivity to mutagens, spontaneous chromosome breakage, and mutation frequency in nevoid basal cell carcinoma syndrome.

Genetic instability in nevoid basal cell carcinoma syndrome (NBCCS) was investigated by measuring in lymphocytes obtained from four patients the level of UV-induced DNA repair synthesis, the DNA replication rate after treatment with different mutagens (UV light, mono- and bifunctional alkylating agents), the baseline mutation frequency, and the spontaneous chromosome breakage. All the parameters analyzed showed normal values; only the response to mitogens in NBCCS lymphocytes was delayed in comparison to that in normal donors. Our findings indicate that chromosomal instability and cellular UV hypersensitivity described in some NBCCS patients are not distinctive and constant features of NBCCS.

Adolescent↗
PubMed1982

Effect of solid detergent washing on values of skin electrical impedance.

We have studied the electrical behaviour of the skin on 20 volunteers, before and after cleaning with solid detergent. The aim was to study one of the possible variables of the measurements. The results have shown that the cleaning has globally reduced the electrical skin parameters of the forehead, without influencing other parts examined (dorsal and palmar surfaces of the hand). The result has been attributed to the elimination of the hydrolipidic film of the surface and in particular that of the sebum of the forehead. The data give an idea as to how to obtain more homogeneous final results, as well as studying the sebum production function.

Adolescent↗
PubMedDate not supplied

Predicting visual assessment of allergic patch test reactions by non-invasive measurements.

The quantification of allergic patch test reactions to several compounds was evaluated on patients using laser Doppler velocimetry (LDV), transepidermal water loss and colorimetry. The correlation between visual scores and instrumental measurements was investigated by the implementation of a modern statistical method: a classification tree. The LDV showed the highest correlation with the severity of the reaction. The best prediction model was obtained when the data of the three instruments were considered together. Using the classification tree methodology, a model of classification, independent of human observation, was developed. The technique can not only predict an allergic reaction for a new patient, but can also give a measure of how reliable its predictions are. This new method, when entirely standardised and approved, could help in the harmonisation of patch test reactions in different laboratories, thus allowing a more homogenous interpretation of these reactions.

Adult↗