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At least 109 records · Page 6Linked to original sources
PubMed1995

Role of appendages in skin resistance and iontophoretic peptide flux: human versus snake skin.

PURPOSE: 1. The assessment of the role of hair follicles and sweat glands in skin resistance and percutaneous iontophoretic flux of 9-desglycinamide, 8-arginine vasopressin (DGAVP) by comparing two skin species: human stratum corneum which contained hair follicles, sweat and sebaceous glands, and shed snake skin which lacked all appendages. 2. The effect of 1-dodecylazacycloheptan-2-one (dodecyl-Azone, a lipid perturbing agent) on the iontophoretic DGAVP flux. METHODS: Iontophoresis in vitro was performed in a transport cell (0.79 cm2 area available for percutaneous transport) by 8-hours application of a pulsed constant current of 100 Hz, 50% duty cycle and 0.26 mA.cm-2 current density delivered by a pair of Ag/AgCl electrodes, of which the anode was facing the anatomical surface of the skin samples. RESULTS: The initial resistances of human stratum corneum and shed snake skin samples were of the same order of magnitude (20-24 k omega.cm2) and both skin species showed a comparable resistance-decrease profile during 8-hours iontophoresis, indicating that the resistances were mainly determined by the stratum corneum and not greatly influenced by the appendageal structures. The initial resistances of the skin samples pretreated with dodecyl-azone were less than 50% of the values of untreated samples. Because dodecylazone is known to perturb the ordering of the intercellular lipids, the effect of azone on the resistance confirms that the resistance mainly resides within the intercellular lipids of the stratum corneum. No correlation was found between the iontophoretic DGAVP-flux and the conductance of human skin. For shed snake skin, however, a good correlation was found, indicating that the iontophoretic permeability of human skin in vitro for a peptide such as DGAVP is, unlike shed snake skin, not related to its overall permeability to ions. While the initial resistances of both human and snake skin were in the same order of magnitude and showed the same declining profile during iontophoresis, the steady state iontophoretic DGAVP flux across human stratum corneum was approximately 140 times larger than through shed snake skin. These findings suggest that small ions follow pathways common to both skin types, presumably the intercellular route, while the peptide on the other hand is transported differently: across snake skin presumably along intercellular pathways only, but across human stratum corneum along additional pathways (most likely of appendageal origin) as well. This interpretation is supported by the observations made of the effects of dodecyl-azone on DGAVP-iontophoresis. Pretreatment with dodecyl-azone did not significantly change steady state fluxes and lag times of DGAVP-iontophoresis across human stratum corneum, but resulted in a significant 3-fold lag time decrease and a 3-fold flux increase of DGAVP-iontophoresis across snake skin. CONCLUSIONS: The results of these in vitro studies emphasize the importance of the appendageal pathway for iontophoretic peptide transport across human stratum corneum.

Adult↗
PubMed1953

The relationship of sodium uptake, potassium rejection, and skin potential in isolated frog skin.

1. Isolated surviving frog skin, when bathed with the same kind of diluted Ringer's solution on both sides, shows a negative correlation between net active salt uptake by the epithelium and spontaneous skin potential. Average values of 0.15 to 0.86 microeq. x hr.(-1) x cm.(-2) were measured and correlated with average skin potentials ranging from 107 to 25 mv. 2. Sodium uptake exceeded chloride uptake by about the same amount, irrespective of the height of the skin potential. 3. The same skins which exhibited a negative correlation between net uptake of sodium chloride and skin potential showed a positive correlation between net potassium rejection from the epithelium and skin potential, for voltages above 30 to 40 mv. In skins of voltages lower than this, potassium ions were taken up rather than rejected. Average values for rejection of +11.8 to -0.8 centi-microeq. x hr.(-1) x cm.(-2) were measured. 4. Net fluid uptake, associated with active uptake of sodium chloride, was small and occurred in the direction of the salt uptake. No dependence of net fluid uptake upon skin potential was observed. 5. Skins of winter frogs, pretreated with a commercial purified ACTH preparation, were less active than their respective controls with regard to uptake of sodium chloride. Rejection of potassium was the same in treated and untreated skins. Posterior pituitary factors, as possible contaminants, did not account for the effect of the ACTH preparation. 6. DOCA, DOC, and cortisone did not alter the normal correlation referred to under (1) and (3). 7. In interpreting the experimental results on theoretical grounds, it is suggested (a) that in normal skin, it is the variation in the electric conductance in skin of chloride ions which essentially, although not exclusively, determines the rate of net uptake of sodium chloride, (b) that a factor in the ACTH preparation used, possibly ACTH itself, may have lowered the electric conductance in skin of sodium ions either truly or apparently, (c) that potassium ions are treated by the skin primarily as passive ions. There is some indication that potassium ions are also actively taken up by the epithelium of skin.

Animals↗
PubMedDate not supplied

The impact of two transfer techniques used during skin-to-skin care on the physiologic and behavioral responses of preterm infants.

BACKGROUND: Conservation of energy assumes an important role in the care of infants requiring assisted ventilation, yet little research has been conducted on this group of infants in terms of thermoregulation, oxygenation, heart rate, or sleep states during skin-to-skin care. OBJECTIVES: To compare the impact of two different transfer techniques used in skin-to-skin care (nurse transfer and parent transfer) on physiologic stability and other descriptive measures of physiologic stability related to energy conservation in ventilated preterm infants during and after skin-to-skin care. METHOD: Fifteen ventilated preterm infants weighing a mean of 1,094 g were randomly assigned to receive either parent or nurse-to-parent transfer on the first of 2 consecutive days and the alternate method the following day. Temperature was taken before and after skin-to-skin care. Oxygen saturation and heart rate were recorded minute by minute, and the Assessment of Behavioral Systems Observation (ABSO) scale scores was used to measure physiologic organization, motor organization, self-regulation, and need for caregiver facilitation during transfer to and from the parent and during pre, post, and skin-to-skin periods. RESULTS: Temperature remained stable. Oxygen saturation decreased and heart rate increased when the infant was transferred to and from the parent, but returned to baseline levels during and after skin-to-skin care regardless of the transfer method. Infants showed more physiologic and motor disorganization, less self-regulation, and more need for caregiver facilitation during transfers to and from the parent than during the pre, post, and skin-to-skin care periods. CONCLUSIONS: Both transfer methods resulted in physiologic disorganization. However, during and after skin-to-skin care, infants exhibited no signs of energy depletion.

Adult↗
PubMed2005

Cultured skin loaded with tetracycline HCl and chloramphenicol as dermal delivery system: mathematical evaluation of the cultured skin containing antibiotics.

Dermal patches consisting of cultured human skin with antibiotics, which have a protective effect on wound skin as well as a preventative effect on second infection of the skin, were prepared and mathematically analyzed as a new drug delivery system (DDS) that can be applied to serious skin defects such as severe burns. In the present study, a three-dimensional cultured human skin model (living skin equivalent-high, LSE-high) was used as a cultured skin membrane and tetracycline HCl (TC-HCl) and chloramphenicol (CP) were used as antibiotics. At first, antibiotics were entrapped in the LSE-high from the dermal side through culture medium in order to obtain a drug-loaded LSE-high. The antibiotic release from the drug-loaded LSE-high was then examined and the resulting release data were used to calculate the effective diffusion coefficient of the antibiotics (D(LSE)) and initial loading concentration of the antibiotics (C0) in the LSE-high. The release profile of TC-HCl was represented by general diffusion-limited kinetics, whereas an initial burst effect was found in the release profile of CP. Therefore, the burst effect was taken into account for analyzing the release profile of CP. Stripped skin excised from hairless rats was used as a wound model, and the antibiotic permeation through the skin from aqueous solution was examined and evaluated using differential equations for Fick's second law of diffusion to obtain the effective diffusion coefficient of the antibiotics in the wound skin (D(skin)). Furthermore, the antibiotic permeation profile through the excised stripped skin from the drug-loaded LSE-high was measured and theoretically evaluated by Fick's second law of diffusion with previously obtained parameters (C0, D(LSE), D(skin)) using a newly constructed two- or three-layered diffusion model. The calculated concentrations of TC-HCl and CP in the upper epidermis of the model wound skin were over their minimum inhibitory concentration (MIC) for several hours against various bacteria, suggesting that this dosage system is useful for the treatment of severe burns. In addition, the present analytical method and diffusion model, with the drug-loaded LSE-high and stripped rat skin, are useful tools for evaluating this new DDS.

Administration, Cutaneous↗
PubMed1999

Eye and hair colour, skin type and constitutive skin pigmentation as risk factors for basal cell carcinoma and cutaneous malignant melanoma. A Danish case-control study.

To assess the importance of hair and eye colour, skin type and constitutive skin pigmentation as risk factors for basal cell carcinoma and cutaneous malignant melanoma in fair-skinned Caucasians, we conducted two identical case-control studies in Denmark. We studied 145 cases with basal cell carcinoma and 174 matched controls, and 168 cases with cutaneous malignant melanoma and 176 matched controls. Controls were matched on age, gender and place of residence. Subjects indicated their hair colour before 7 years of age, and at 25 years of age and their skin phototype. Interviewers assessed the present hair colour and eye colour, and the constitutive skin pigmentation was measured objectively by skin reflectance of UV unexposed buttock skin. There were no differences between basal cell carcinoma cases and controls in hair colour or eye colour or constitutive skin pigmentation, but more cases were of skin type II than skin type IV; skin type 11 was a risk factor for basal cell carcinoma with an odds ratio (OR) of 2.3. For cutaneous malignant melanoma, more cases than controls were red-haired or blond and of skin type II, but there was no difference in constitutive skin pigmentation. Hair colour and skin type were found to be independent risk factors for cutaneous malignant melanoma; red hair vs. black/brown: OR >9.7, blond hair vs. brown/black: OR = 2.4, and skin type 11 vs. type IV: OR=2.0. There were no gender-related differences in risk factors for basal cell carcinoma and cutaneous malignant melanoma.

Adult↗
PubMed2003

Impact of atopic skin diathesis on occupational skin disease incidence in a working population.

Present evidence convincingly indicates that workers with occupational skin disease are more frequently affected by atopic skin diathesis than the general working population. Population-based studies estimating the impact of atopic skin diathesis on occupational skin disease in various occupations have not been reported to date. We analyzed data of all initial reports of occupational skin diseases recorded in the register of occupational skin diseases in northern Bavaria, Germany, from 1990 to 1999. The main outcome measure was the attributable risk of atopic skin diathesis on occupational skin disease within 24 occupational groups that are most hazardous to the skin. Of the 5285 registered cases, 3730 had a confirmed occupational causation. Among these, 1366 workers (37%) presented an atopic skin diathesis. Assuming a prevalence of atopic skin diathesis of 20% in the total population, we found that 21.6% (95% confidence interval 19.4; 23.7) of occupational skin disease cases within 24 occupational groups may be ascribed to this endogenous risk factor. The attributable risk of atopic skin diathesis helped to explain a large proportion of occupational skin diseases. Empirical evidence supports the importance of surveying atopic skin diathesis as part of an occupational skin disease prevention strategy.

Adult↗
PubMed2005

Newborn temperature during skin-to-skin breastfeeding in couples having breastfeeding difficulties.

BACKGROUND: Kangaroo (skin-to-skin contact) care facilitates the maintenance of safe temperatures in newborn infants. Concern persists that infants will become cold while breastfeeding, however, especially if in skin-to-skin contact with the mother. This concern might be especially realistic for infants experiencing breastfeeding difficulties. The objective was to measure temperature during a study of mothers and infants who were having breastfeeding difficulties during early postpartum and were given opportunities to experience skin-to-skin contact during breastfeeding. METHOD: Forty-eight full-term infants were investigated using a pretest-test-posttest study design. Temporal artery temperature was measured before, after, and once during 3 consecutive skin-to-skin breastfeeding interventions and 1 intervention 24 hours after the first intervention. RESULTS: During skin-to-skin contact, most infants reached and maintained temperatures between 36.5 and 37.6 degrees C, the thermoneutral range, with only rare exceptions. CONCLUSIONS: The temperatures of study infants reached and remained at the thermoneutral range during breastfeeding in skin-to-skin contact. The data suggest that mothers may have the ability to modulate their infant's temperature during skin-to-skin contact if given the opportunity. Hospital staff and parents can be reassured that, with respect to their temperature, healthy newborn infants, with or without breastfeeding difficulties, may safely breastfeed in skin-to-skin contact with their mothers.

Adult↗
PubMed2004

Microvascular response in guinea pig skin to histamine challenge with and without application of skin window.

We measured the microvascular response to histamine in guinea pig skin. Histamine (40 mg ml(-1)) was given either as a skin prick test or applied topically onto a skin window. The skin window was prepared by applying suction and gentle warming to the skin so that a blister was formed, and by removing the top of the blister. The microvascular response was measured as the accumulation of radiolabelled transferrin in the skin in vivo, reflecting a combination plasma exudation and vasodilatation. In the control (saline) challenge, the response was slightly greater in the skin window than after skin prick challenge and the scatter was larger. Histamine challenge resulted in a significant microvascular response with respect to the control situation when measured immediately after provocation for both challenge techniques. Ten minutes after challenge, a smaller response was measured, which was still significantly greater than control for the skin prick challenge, but not for topical provocation using the skin window technique. We conclude that the microvascular response to histamine after provocation with the skin prick technique is similar to that after topical provocation using the skin window technique. The skin window technique may have a lower sensitivity than the skin prick technique owing to a higher scatter in the control situation. This difference should be considered when performing and interpreting studies of the microvascular reaction in the skin.

Administration, Topical↗
PubMed2006

A skin color mutation of grapevine, from black-skinned Pinot Noir to white-skinned Pinot Blanc, is caused by deletion of the functional VvmybA1 allele.

A white-wine grape, Pinot Blanc, is thought to be a white-skinned mutant of a red-wine grape, Pinot Noir. Pinot Noir was heterozygous for VvmybA1. One allele was the non-functional VvmybA1a, and the other was the functional VvmybA1c. In Pinot Blanc, however, only VvmybA1a was observed, and the amount of VvmybA1 DNA in Pinot Blanc was half that in Pinot Noir. These findings suggest that deletion of VvmybA1c from Pinot Noir resulted in Pinot Blanc.

Alleles↗
PubMed1980

Chronic hydroquinone poisoning of the skin from skin-lightening cosmetics. A South African epidemic of ochronosis of the face in dark-skinned individuals.

Attention is drawn to the widespread use of bleaching preparations by Black women. These products often contain hydroquinone. They act efficiently as bleaching agents, but chronic oversaturation of the skin with hydroquinone eventually produces ochronosis. This complication has reached epidemic proportions in the Transvaal. Although the assay of hydroquinone in cosmetic products has not yet been standardized, we present some provisional results. The clinical, social and industrial aspects are also significant.

Black or African American↗
PubMed1987

Possible functional impairment of Langerhans' cells in vitiliginous skin. Reduced ability to elicit dinitrochlorobenzene contact sensitivity reaction and decreased stimulatory effect in the allogeneic mixed skin cell lymphocyte culture reaction.

We used patch testing to compare the ability to elicit contact sensitivity to dinitrochlorobenzene (DNCB) of uninvolved with vitiliginous skin of 31 patients with vitiligo. The induction of DNCB contact sensitivity was possible in the vitiliginous skin in the same way as in normal skin. The DNCB contact sensitivity reactions, however, were generally diminished in vitiliginous skin, although the number of cases showing similar DNCB contact reactivity between normal and vitiliginous skin increased when the sensitization procedure was performed in vitiliginous skin instead of normal skin. On the other hand, delayed skin reactions to intradermally injected Candida albicans antigen were not suppressed in vitiliginous skin. The number of Langerhans' cells was not decreased in vitiliginous skin as compared with that of normal skin. The epidermal cells derived from vitiliginous skin, however, tended to show a lower stimulatory effect in the allogeneic mixed skin cell lymphocyte culture reaction than those from normal skin. These results suggest a possibility of functional impairment of Langerhans' cells in vitiliginous skin.

Antigens, Fungal↗
PubMedDate not supplied

Quantification of skin elasticity changes associated with pulsed carbon dioxide laser skin resurfacing.

BACKGROUND: While skin resurfacing using pulsed carbon dioxide lasers appears to have a skin-tightening effect clinically, the debate continues over its actual effects on dermal collagen. OBJECTIVES: To provide quantitative measures of skin elasticity changes associated with pulsed carbon dioxide laser skin resurfacing and to introduce to the facial plastic surgery community the Cutometer SEM 575 skin elasticity meter, an instrument that is useful in the measurement of skin elasticity. SETTING: University-based facial plastic surgery clinic and wound healing laboratory. DESIGN: Intervention. MAIN OUTCOME MEASURES: Measurements taken prior to and 6 months after procedure. SUBJECTS AND INTERVENTION: Thirty-two patients undergoing pulsed carbon dioxide full-face laser skin resurfacing participated. There were 12 test sites measured in 6 aesthetic units per participant. The Cutometer SEM 575 skin elasticity meter was used to measure skin elasticity changes accompanying this procedure. This device measures skin deformation with an accuracy of 10 microns. RESULTS: The change in elastic recovery (Ur/Ue) was determined. At all 6 of the facial sites, there was a statistically significant increase in skin elasticity (P < .001). Overall, there was an 18.2% improvement in skin elasticity. Site-specific changes ranged from 9% (forehead) to 22% (prejowl and periorbital). CONCLUSIONS: Skin resurfacing with the pulsed carbon dioxide laser produces a true skin-tightening effect. The Cutometer is a valuable instrument that permits accurate quantification of skin elasticity and may be useful in the evaluation of other facial plastic procedure results.

Adult↗