PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Skin”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Comparison of secondary ischemia tolerance between free skin flap and island skin flap raised on the buttock of the pig].

OBJECTIVE: This study was to compare skin viability of the free skin flap and the island skin flap in the pig. METHODS: The comparison was made between the 8 cm x 11 cm surgically denervated free skin flap and the pedicle island skin flap raised contralaterally on the buttock of 50 pigs. The free flap and the pedicle flap were subjected to 2 h of primary warm ischemia followed by 12 h of reperfusion and 0, 2, 4, 6, 10 h of secondary warm ischemia (n = 10). Skin viability was assessed 7 days after secondary ischemia. RESULTS: Pedicle skin flaps tolerated up to 10 h secondary ischemia without skin necrosis. However, incidences of flap failure (partial or total) in free flaps subjected to 0, 2, 4, 6, 10 h of secondary ischemia were 0, 10%, 50%, 80%, 100%, respectively. In a separate experiment, skin blood flow was studied in contralateral free skin flaps and pedicle island flaps (n = 20) subjected to 4 h of secondary ischemia. The skin reperfusion was very slow in 8 out of 20 free skin flaps at 1, 5 h after secondary is chemia, and the mean skin blood flow measured by 15 microns microspheres in these 8 free skin flaps was only 8% of their contralateral pedicle skin flaps. The mean skin blood flow in the remaining 12 free skin flaps was 76% of their contralateral pedicle skin flap. CONCLUSION: These observations were interpreted to indicate that buttock free skin flaps in the pig were less tolerant to secondary ischemia compared with their contralateral pedicle skin flaps subjected to the same ischemic protocol, and this reduced ischemic tolerance in free skin flaps was associated with compromised skin blood flow.

Animals↗
PubMed1989

Effect of capsulectomy on the hemodynamics and viability of random-pattern skin flaps raised on expanded skin in the pig.

Skin flaps constructed on expanded skin usually include the underlying capsular tissue. It has been hypothesized that capsulectomy may jeopardize the viability of the expanded skin flap. The experiments reported herein were designed to test this hypothesis. Specifically, we studied the hemodynamics and viability of random-pattern skin flaps (8 X 20 cm) raised on delayed bipedicle flaps (group A) and on expanded skin pockets with capsulectomy at the time of flap elevation (group B) or with intact underlying capsular tissue (group C). Each group was randomly assigned to each flank in 16 pigs. Skin pockets were expanded by inflation of subcutaneous silicone tissue expanders with sterile saline (299 +/- 7 ml; X +/- SEM) over a period of 3 weeks. At the end of this period, the bipedicle flaps were constructed. Eight days later, random-pattern skin flaps were raised on bipedicle flaps and skin pockets. The length and area of skin flap viability, judged by the fluorescein dye test performed 1 day postoperatively, were not significantly different (p greater than 0.05) among groups A, B, and C (n = 31 to 32). There also were no significant differences (p greater than 0.05) in total skin capillary blood flow measured 1 day postoperatively (A = 2.6 +/- 0.4, B = 2.4 +/- 0.4, and C = 2.7 +/- 0.6 ml/min per flap; n = 15 to 16) and in skin viability assessed 7 days postoperatively (A = 74 +/- 2, B = 75 +/- 2, and C = 76 +/- 2 percent; n = 16) among delayed skin flaps and skin flaps raised on expanded skin pockets with or without capsulectomy. The results of this flap viability study were confirmed in 5 minipigs in a separate experiment. We conclude that capsulectomy did not have a detrimental effect on the hemodynamics and viability of random-pattern skin flaps raised on expanded skin. Furthermore, we hypothesize that skin flaps raised on expanded skin are similar to delayed skin flaps in that the skin blood flow is optimally augmented; therefore, the capsular tissue does not add significant blood supply to the overlying skin.

Animals↗
PubMed2005

A randomised controlled trial in the north of England examining the effects of skin-to-skin care on breast feeding.

OBJECTIVE: to examine the effect of early skin-to-skin contact between mothers and their healthy full-term babies on initiation and duration of breast feeding. DESIGN: a randomised controlled trial comparing skin-to-skin with routine care. SETTING: Warrington Hospital, Cheshire, UK. PARTICIPANTS: 204 mother and baby pairs; 102 randomised to each group. OUTCOME MEASURES: success of first breast feed, maternal satisfaction with skin-to-skin care and preference for future post-delivery care, baby-body temperature 1 hr after birth, partial or exclusive breast feeding at 4 months. FINDINGS: in the skin-to-skin group, 89 out of 98 (91%) babies had a successful first feed compared with 82 out of 89 (83%) in the routine care group. The difference in the success rate was 8%, 95% confidence interval (CI) (-1.6%, 17.6%); chi(2)=2.7; df=1; P=0.10. Forty-two out of 97 (43%) babies given skin-to-skin were partially or exclusively breast feeding at 4 months compared with 40 out of 100 (40%) of babies in the routine care group. The difference in breast-feeding rate at 4 months was 3.3%, 95% CI (-10.3%, 16.7% ); chi(2)=0.22; df=1; P=0.64. The mean temperature 1 hr after birth was higher with skin-to-skin than routine care. The difference in means was 0.15 degrees C; 95% CI (0.03, 0.28); P=0.02. A larger proportion of mothers (87/97 [90%]) were very satisfied with skin-to-skin care, compared with 60 out of 102 (59%) in the control group; 83 out of 97 (86%) of the mothers in the intervention group said that they would prefer to receive the same care in the future compared with 31 out of 102 (30%) mothers in the control group. CONCLUSIONS: the difference between the groups in the success rate for the first breast feed and rates at 4 months was not statistically significant. However, mothers who had skin-to-skin contact enjoyed the experience, and most reported that they would choose to have skin-to skin care in the future. In this, the largest trial to date, previous concerns about baby-body temperature after skin-to-skin care were dispelled.

Adult↗
PubMed2001

A noninvasive method to assess skin irritation and compromised skin conditions using simple tape adsorption of molecular markers of inflammation.

BACKGROUND/AIMS: We have developed a simple noninvasive method to assess inflammatory changes in human skin, even in the absence of visible clinical irritation. Our approach is based on a simple tape (Sebutape) adsorption method to recover molecular mediators of skin inflammation (e.g., cytokines). This procedure has been used to investigate baseline cytokine levels on skin, to assess normal skin condition and to evaluate changes due to chemical insult, existing dermatitis, or sun exposure. METHODS: In clinical studies, Sebutape was applied to normal appearing uncompromised skin, as well as to compromised (diaper or heat rash), chemically treated (sodium laurel sulfate), or sun-exposed skin. Sebutape was applied to the skin for a 1 min collection interval. Tapes were extracted in saline using a 10 min sonication, and the extracts were analyzed for human interleukin-1alpha (IL-1alpha), IL-1 receptor antagonist (IL-1RA) and IL-8 using commercial immunoassay test kits. The cytokine levels recovered from each tape extract were normalized to total protein (TP) levels. In infant product use tests, the severity of skin irritation (diaper and heat rash or erythema) was also assessed using a visual grading scale. RESULTS: The method itself caused minimal, if any, skin damage. Additionally, Sebutape was shown to quantitatively adsorb detectable levels of cytokine from normal-appearing (control) or compromised (e.g., rashed or chemically treated) skin. In infant studies, significant increases in IL-1alpha levels were found in skin exhibiting diaper rash, heat rash and erythema compared with normal appearing control skin sites. When these results were normalized to total protein levels recovered from each tape, the significance was maintained. A positive correlation (r2=0.82) existed between IL-1RA levels and diaper rash severity. Significant increases in IL-8 levels were recovered from diaper rash versus control skin sites. There were differences in baseline cytokine levels in normal skin related to body site and sun exposure. The IL-1 RA/IL-1alpha ratios for sun-exposed skin of the face and lower leg were significantly (P<0.05) higher (3-6-fold) than those for skin sites that typically receive minimal sun exposure (i.e., underarm, upper leg and upper back). There was a significant increase in IL-1alpha and a directional increase in IL-8 levels in adult skin sites treated with the irritant, sodium lauryl sulfate, even in the absence of visible skin irritation (erythema). CONCLUSION: Our results demonstrate that this method is a useful noninvasive technique for assessing skin inflammatory events. In addition, the method is simple and easily applied in a clinical setting, whether on infants or adults.

Adhesives↗
PubMed1984

Pathophysiology of skin flaps raised on expanded pig skin.

The pathophysiology of skin flaps raised on nonexpanded and expanded skin was studied in pigs. Skin expansion was achieved by gradual inflation of a subcutaneously implanted silicone tissue expander with sterilized isotonic saline over a period of 4 to 5 weeks. Comparisons were made of the skin flap viability and capillary blood flow among random acute and delayed skin flaps and skin flaps constructed on skin pockets implanted with noninflated or inflated tissue expanders. The extents of skin flap viability and capillary blood flow were similar among delayed skin flaps and skin flaps constructed on skin pockets but were significantly higher than those of acute random skin flaps raised on normal skin. It was concluded that skin viability and capillary blood flow in skin flaps raised on expanded skin were not compromised and the regulation of blood flow in skin flaps raised on nonexpanded or expanded skin pockets was similar to that seen in delayed skin flaps. The mechanisms of the delay phenomenon was discussed.

Animals↗
PubMed1997

Body temperatures and oxygen consumption during skin-to-skin (kangaroo) care in stable preterm infants weighing less than 1500 grams.

BACKGROUND: More and progressively smaller preterm infants are taken out of the incubator and placed skin to skin on their mother's chest to promote bonding, despite concerns that the infants are exposed to cold during this intervention. OBJECTIVE: To test the hypothesis that skin-to-skin care is a cold stress for preterm infants weighing less than 1500 gm, with a decrease in rectal temperature, a decrease in peripheral skin temperature, or an increase in oxygen consumption compared with conditions monitored during incubator care. STUDY DESIGN: We studied 22 stable, spontaneously breathing preterm infants weighing less than 1500 gm (appropriate in size for gestational age), who had their first skin-to-skin care in the first week of life. We continuously measured rectal temperature, peripheral skin temperature (foot), and oxygen consumption (indirect calorimetry) for 1 hour in a thermoneutral incubator, during 1 hour of skin-to-skin care, and for another hour in the incubator. Mean values for the three periods were compared by analysis of variance. RESULTS: During skin-to-skin care the mean rectal temperature was 0.2 degree C (p < 0.01) and the peripheral skin temperature was 0.6 degree C (p < 0.01) higher than during the preceding hour in the incubator. Back in the incubator, body temperatures returned to values recorded before skin-to-skin care. Oxygen consumption during skin-to-skin care (6.1 +/- 0.9 ml/kg per minute) was not significantly higher than in the incubator (5.8 +/- 0.8 ml/kg per minute). CONCLUSION: For stable preterm infants weighing less than 1500 gm and less than 1 week of age, 1 hour of skin-to-skin care is not a cold stress compared with care in a thermoneutral incubator.

Body Temperature↗
PubMed1997

Evaluation of Yucatan micropig skin for use as an in vitro model for skin permeation study.

Skin permeation rates of five non-steroidal anti-inflammatory drugs, three of them lipophilic (ibuprofen, indomethacin and ketoprofen) and two hydrophilic (sodium diclofenac and antipyrine), through Yucatan hairless micropig (YMP) full-thickness skin were determined in vitro using Franz-type diffusion cells, and the usefulness of YMP skin as an animal model skin was investigated. Five-month-old YMP skin showed small variation with respect to drug permeation rates, if the region of skin site was the same. But skin from 6-month-old YMPs showed faster and varied permeation rates due to skin defects. In the case of hydrophilic drugs, no effects on permeation due to the region from which the skin was obtained were observed, although higher permeation rates were observed through the flank than through dorsal skin in the case of ibuprofen and ketoprofen. For YMP skin, the permeation coefficients of drugs were lower than those for hairless rat skin, especially for hydrophilic drugs. Compared with reported human data on permeation coefficients, the permeation coefficients of drugs through YMP skin were 1/2-1/8 of those through human skin, regardless of whether the drugs were hydrophilic or lipophilic. YMP skin could be used as an in vitro animal skin model because of the reproducibility of the permeation rate of drugs through this skin and its similarity to human skin.

Administration, Topical↗
PubMed1995

Biophysical properties of dry atopic and normal skin with special reference to effects of skin care products.

During recent years several highly developed non-invasive methods for evaluation of skin physiology and pathology have been introduced. Against this background, the present studies were undertaken with the primary aim of assessing the effects of various skin care products on some properties of the skin. Skin topography was measured by profilometry on skin replicas, friction with a newly developed friction instrument, capacitance with a Corneometer, and barrier function both with an Evaporimeter to assess transepidermal water loss (TEWL) and by application of an irritant followed by measurement of the resulting irritative reaction. Initially some of the techniques were used to further characterize the differences between dry atopic skin and normal skin. Dry skin exhibits increased values of roughness parameters and a reduced number of topographical peaks. TEWL is increased, indicating impaired barrier function. The friction and capacitance are lower and correlate significantly to each other, whereas TEWL does not appear to relate to either of these parameters. The use of a scrub cream removes the outermost part of the stratum corneum, resulting in a smoother skin. Application of moisturizers modifies the frictional response of the skin. The friction instrument gave results comparable to those of panelists trained in sensory evaluation. The study suggests that measurement of skin friction can be used to predict the degree of liking of moisturizers. Furthermore, moisturizers increase the skin hydration. They provide water directly to the skin from their water phase. Skin hydration also increases with increased degree of occlusion, as measured as a decrease in TEWL. Moisturizers may also alter the diffusional resistance of the stratum corneum and reduce the skin susceptibility to the surfactant sodium lauryl sulphate (SLS). Lipids in moisturizers may influence already developed SLS-induced irritation. A significantly lower degree of irritation was found in areas treated with canola oil and its sterol-enriched fraction than in an area treated with water. These findings emphasize that skin care products do not only form an inert, epicutaneous layer, but that they may penetrate and influence the structure and function of the skin.

Adolescent↗
PubMedDate not supplied

Parents' perception of skin-to-skin care with their preterm infants requiring assisted ventilation.

OBJECTIVE: To explore parents' perception of skin-to-skin care with their preterm infant who is on assisted ventilation, and to elucidate factors influencing the decision to continue or discontinue skin-to-skin care. DESIGN: Naturalistic inquiry, using open-ended, transcribed and audiotaped face-to-face and telephone interviews. SETTING: Tertiary neonatal care setting and homes of parents. PARTICIPANTS: Eight mothers and one father who participated in skin-to-skin care. INTERVENTIONS: Two 60-minute skin-to-skin care sessions. RESULTS: Three themes emerged: (a) ambivalence of parents toward skin-to-skin care, including subthemes of yearning to hold the infant and apprehension to do so; (b) need of a supportive environment; and (c) special quality of the parent-infant interaction, including subthemes of intense connectedness and active parenting. Perceptions of apprehension, need for a supportive environment, and active parenting differed between parents who continued skin-to-skin care during their infants' hospitalization and parents who did not. Three of the four parents who discontinued skin-to-skin care in the hospital resumed when their infants were home. CONCLUSIONS: Differences in narratives of parents highlighted the importance of individualizing the skin-to-skin experience to the needs of parent and infant. Parents who resumed skin-to-skin care at home valued the experience while their infant was hospitalized but needed intervention to alleviate their apprehension, enhance their feeling of autonomy, and modify the environment.

Adult↗
PubMed2005

Salivary cortisol and mood and pain profiles during skin-to-skin care for an unselected group of mothers and infants in neonatal intensive care.

OBJECTIVES: Mother-infant separation after birth is a well-known source of stress. Parents and preterm infants in neonatal intensive care are separated immediately after birth. Skin-to-skin care is 1 possible method to reduce the separation-dependent stress. The aim of the present study was to investigate how skin-to-skin care influences stress for the mother and the infant in neonatal intensive care. METHODS: Seventeen mother-infant pairs were included at their first and fourth skin-to-skin care. The infants were 25 to 33 weeks' gestational age, with birth weights ranging from 495 to 2590 g. In mothers, salivary cortisol, heart rate, mood scale, and stress measured on a visual analog scale (VAS) were analyzed. In infants, salivary cortisol and heart rate were analyzed, and because pain is one facet of stress, 2 different pain scales were used. RESULTS: In mothers, the skin-to-skin care decreased salivary cortisol (32%), heart rate (7%), and VAS (89%), whereas mood increased (6%). Before the fourth skin-to-skin care, mothers rated less stress on VAS, and salivary cortisol and heart rate improved faster. The infants' cortisol either increased or decreased. Their heart rates and pain scores decreased during skin-to-skin care. CONCLUSIONS: Our results lend additional support to the value of skin-to-skin care in neonatal intensive care. Variable stress responses in preterm infants favor the need for individualized care. The mothers' need for support seem to be more pronounced in the first skin-to-skin session as our results show a higher degree of stress as compared with later skin-to-skin care.

Adult↗
PubMed2002

Skin permeation enhancement effect and skin irritation of saturated fatty alcohols.

Though the skin permeation enhancement effect of chemical penetration enhancers has been studied extensively, their skin irritation potential has not been adequately investigated. The objective of this study was to evaluate the skin permeation enhancement effect and skin irritation of saturated fatty alcohols using melatonin as a model compound. A saturated solution of melatonin in a mixture of water and ethanol (40:60) containing 5% w/v of saturated fatty alcohol was used in the skin permeation studies using Franz diffusion cells. For skin irritation studies, 230 microl of fatty alcohol solution was applied on the dorsal surface of the hairless rats using Hill top chamber. The skin irritation was evaluated by visual scoring method and bioengineering methods such as measurement of transepidermal water loss (TEWL) and skin blood flow. The flux of melatonin across hairless rat skin was found to be dependent on the carbon chain length of the fatty alcohols, with decanol showing the maximum permeation of melatonin. All fatty alcohols increased the TEWL and skin blood flow significantly compared with the vehicle. The fatty alcohols (decanol, undecanol and lauryl alcohol), which showed greater permeation of melatonin, also produced greater TEWL, skin blood flow and erythema. Tridecanol and myristyl alcohol showed lower permeation enhancement effect but caused greater skin irritation. Octanol and nonanol may be the most useful enhancers for the transdermal delivery of melatonin considering their lower skin irritation and a reasonably good permeation enhancement effect. However, further studies are needed to ascertain their safety as skin penetration enhancers. Skin permeation and skin irritation in experimental animals such as rats are generally higher compared with human skin. Further studies in human volunteers using fatty alcohols at the concentrations of 5% or lower may provide useful information on the utility of these fatty alcohols as permeation enhancers.

Administration, Cutaneous↗
PubMed1999

Cutaneous side effects from laser treatment of the skin: skin cancer, scars, wounds, pigmentary changes, and purpura--use of pulsed dye laser, copper vapor laser, and argon laser.

It has been the intention of this thesis to increase the knowledge on the development of cutaneous side effects from treatment with the argon laser, the copper vapor laser, and the pulsed dye laser, which represent technical developments within laser systems used for treatment of vascular lesions. To reach that goal, the investigations focused on patient and lesional characteristics (skin pigmentation, skin redness, and epidermal thickness) and on the importance of UV irradiation before and after dermatological laser treatment. The aspect of UV irradiation was added because vascular lesions frequently involve the face and, therefore, may be exposed to sunlight in relation to laser treatment. Risk assessments were performed on clinically visible side effects in order to improve the preoperative information to the patients about their individual risks of obtaining side effects from dermatological laser treatment. The laser-induced side effects were evaluated by systematic clinical assessments, by histological and biochemical examinations, by skin reflectance measurements, optical profilometry, and ultrasonography. The term side effects is associated with both transient and permanent skin reactions such as purpura, wounds, textural changes, scars, pigmentary changes, and squamous cell carcinomas. Lightly pigmented, hairless hr/hr C3H/Tif mice, hairless, albino hr/hr MORO/Ibm mice, human, healthy volunteers, and children with port-wine stains were included in the studies. This thesis represents the first systematic and experimental approach to selected side effects from laser treatment of the skin. The argon laser (AL) and the copper vapor laser (CVL) The results from AL and CVL treatments are described together because these lasers are continuous/quasicontinuous lasers that do not meet the requirements for selective photothermolysis, which represents the most selective delivery of energy to cutaneous vessels. In normal-skinned human volunteers, the postoperative development of scars and pigmentary alterations depended on the preoperative constitutive skin pigmentation degree. Significant correlations were found between the preoperative skin pigmentation and the clinically scored pigmentary changes and scarring 1, 2, and 6 months postoperatively, indicating that dark-pigmented skin types respond with more heavy skin reactions than fair-pigmented skin types. Pigmentary changes occurred at lower intensity levels than scarring. No difference was seen between the AL and the CVL concerning the risk of inducing these side effects. In hairless, albino hr/hr MORO/Ibm mice increasing epidermal thicknesses reduced CVL-induced wounds and scars. Significant negative correlations were found between preoperative epidermal thicknesses and CVL-induced skin reactions. In lightly pigmented, hairless hr/hr C3H/Tif mice, CVL treatment induced an increase in skin pigmentation, evaluated by a semiquantitative technique. Postoperative UV irradiations with simulated solar UV increased the CVL-induced skin pigmentation additionally. The size of CVL-induced wounds and scars tended to enlarge by preoperative UV irradiations. In contrast, CVL-induced wounds were diminished and had a prolonged wound healing time when postoperative UV irradiations were given. This may indicate a deep constricted skin damage. Moreover, the histologically evaluated fibrosis and the frequency of bulging infiltration were increased by postoperative UV irradiation. When taking the liberty to extend the obtained results from the animal studies to humans, these results support the importance of pre- and postoperative sunprotection. Regarding skin cancer, in hairless mice it was found that one treatment with the CVL did not have a malignant potential itself. Pretreatment with the CVL at the highest intensity level (1.4W) delayed UV-induced photocarcinogenesis significantly. The pulsed dye laser (PDL) The PDL is described separately because it is the only laser in this thesis that fulf

Adult↗
PubMed2002

Autologous skin transplantation: comparison of minced skin to other techniques.

BACKGROUND: Skin grafting may be necessary to close nonhealing skin wounds. This report describes a fast and minimally invasive method to produce minced skin suitable for transplantation to skin wounds. The technique was evaluated in an established porcine skin wound healing model and was compared to split-thickness skin grafts and suspensions of cultured and noncultured keratinocytes. MATERIALS AND METHODS: The study included 90 wounds on 3 pigs. Fluid-treated full-thickness skin wounds were grafted with minced skin, split-thickness skin grafts, noncultured keratinocytes, or cultured keratinocytes. Controls received either fluid or dry treatment. The wound healing process was analyzed in histologies collected at Days 8 to 43 postwounding. Wound contraction was quantified by photoplanimetry. RESULTS: Wounds transplanted with minced skin and keratinocyte suspension contained several colonies of keratinocytes in the newly formed granulation tissue. During the healing phase, the colonies progressed upward and reepithelialization was accelerated. Minced skin and split-thickness skin grafts reduced contraction as compared to keratinocyte suspensions and saline controls. Granulation tissue formation was also reduced in split-thickness skin-grafted wounds. CONCLUSIONS: Minced skin grafting accelerates reepithelialization of fluid-treated skin wounds. The technique is faster and less expensive than split-thickness skin grafting and keratinocyte suspension transplantation. Minced skin grafting may have implications for the treatment of chronic wounds.

Animals↗
PubMed2003

Differential expression of cornified cell envelope precursors in normal skin, intraorally transplanted skin and normal oral mucosa.

BACKGROUND: Skin flaps have routinely been used as substitutes for oral mucosa after extensive resection of oral tissues. However, it remains unknown how the transplanted skin flaps perform as a host defence in the new environment of the oral cavity. OBJECTIVES: To evaluate the expression of cornified cell envelope (CCE) precursors in pretransplanted (normal) skin, intraorally transplanted skin and normal oral mucosa, because CCEs are highly responsible for a protective barrier in each type of epithelium. METHODS: We used immunohistochemistry and immunoelectron microscopy to examine the expression of CCE precursors, small proline-rich protein (SPR) 2 and 3 and loricrin, in biopsy specimens of normal skin, transplanted skin and normal oral mucosa, including buccal and lingual (non-keratinized) mucosae, and palatal (keratinized) mucosa. RESULTS: Transplanted skin flaps were classified into two groups. About two-thirds of the transplanted skin flaps displayed a reddish appearance and were devoid of the stratum corneum (SC) together with a psoriasiform inflammatory tissue reaction. Others showed a native appearance, retaining the SC. While SPR2 expression was limited to the stratum granulosum (SG) in both normal and transplanted skin retaining the SC, it extended to the stratum spinosum (SS) of the transplanted skin lacking the SC and that of the normal oral mucosa. Although SPR3 expression was not found in normal skin or in the transplanted skin retaining the SC, it was strongly expressed in the SS of the transplanted skin lacking the SC and the non-keratinized oral mucosa, and in the SS and SG of the keratinized oral mucosa. Loricrin, which was expressed in the SG of normal skin, the transplanted skin retaining the SC and the keratinized oral mucosa, was not detected in the transplanted skin lacking the SC or in the non-keratinized oral mucosa. Immunoelectron microscopy confirmed the ultrastructural localization of SPR3 directly under the cytoplasmic membrane of keratinocytes of the transplanted skin lacking the SC and that of the oral mucosa. CONCLUSIONS: The altered expression of SPR2, SPR3 and loricrin reflects the possible adaptation of epidermal keratinocytes in the new environment of the oral cavity.

Cheek↗
PubMed2002

Rapid alignment of collagen fibers in the dermis of undermined and not undermined skin stretched with a skin-stretching device.

A controlled, quantitative histochemical study was performed in five piglets to establish changes in undermined and not undermined stretched skin. The skin was stretched with a stretching device for 30 minutes to close a large skin defect. On each flank of the piglet, at a standard position, 9 x 9-cm wounds were created under general anesthesia. On one flank, the surrounding skin was undermined cranially and caudally over a 10-centimeter area. Sections of skin biopsies obtained during stretching were stained with picrosirius red and studied with routine light microscopy and polarized light microscopy in combination with image analysis. The length of collagen fibers was analyzed as a parameter of changes in the dermis resulting from skin stretching. This newly developed quantitative method appeared to be valid, specific, and reproducible, allowing for objective determination of changes in the length of the fibers in the plain of the sections. Changes in the orientation of collagen fibers in the dermis as a result of skin stretching were thereby determined. Epidermal thickness did not change significantly under the influence of stretching forces in both undermined and not undermined skin. However, the orientation of the collagen fibers changed significantly as a result of skin stretching. In undermined wounds, parallel alignment and elongation of the fibers in the plane of the sections was already observed after 15 minutes of stretching. The fibers became aligned in the direction of the stretching force, perpendicular to the wound margin. After 30 minutes of stretching, the mean major axes of the collagen fibers were longest in the plane of the sections (p < 0.001). This meant that elongation and parallel alignment of the collagen fibers had occurred. Stretching of not undermined skin for 15 minutes resulted in significantly stronger parallel alignment in the plane of the sections as compared with undermined skin. This was less well defined after 30 minutes of stretching in not undermined skin. It is concluded that skin stretching with a skin-stretching device for 30 minutes results in significant histomorphological changes of collagen fibers in the dermis of both undermined and not undermined skin. The fibers realign rapidly as a result of stretching forces and become aligned in the direction of the stretching force, perpendicular to the wound margin. These dynamic changes in collagen fibers explain the significantly decreased wound closing tension resulting from skin stretching and explain how skin stretches beyond its inherent extensibility.

Animals↗
PubMed1997

From newborn to adult: phenotypic and functional properties of skin equivalent and human skin as a function of donor age.

The skin's most important function is to act as a barrier against fluid loss, microorganism infections, and percutaneous absorption. To fulfill this role, keratinocytes proliferate and differentiate to produce a protective layer: the stratum corneum. Because stem cells are responsible for the production of differentiated progeny and stem cells (K19-expressing cells) are less abundant in skin from older donors, the purpose of this study was to establish whether histological and functional properties of differentiating skin is influenced by donor age. The in vitro model developed for the evaluation of skin properties (Michel et al., 1995) was used to produce skin equivalents from newborn, child, and adult keratinocytes. Throughout maturation, skin equivalents were compared with corresponding skin biopsies for keratin, filaggrin, and transglutaminase expression. Percutaneous absorptions of hydrocortisone also were measured and correlated with lipid content. After 1 wk of immersed culture, the epidermal layer of newborn skin equivalents was thicker than child and adult epidermis. As expected, a greater proportion of cutaneous stem cells was present in newborn compared with children and adult skin equivalents. No age-related difference was observed for differentiation markers. When skin equivalents were cultured at the air-liquid interface, cell differentiation and stratum corneum formation were induced, and the age-related variation in the thickness of the epidermal layer disappeared. Percutaneous absorption through these matured skin equivalents did not vary with age. Their lipid density and profile were similar. Accordingly, skin biopsies exhibited comparable percutaneous absorption profiles independently of donor age. In conclusion, although newborn skin equivalents, or skin biopsies, contained more stem cells than child and adult counterparts, no age-related histological difference was observed in the differentiated tissues. Moreover, the functional barrier property of skins and matured skin equivalents did not vary with age. Therefore, both newborn and adult keratinocytes produce useful in vitro models to study epidermal differentiation processes involved in both normal and pathological states.

Absorption↗
PubMed2001

Comparison of human skin or epidermis models with human and animal skin in in-vitro percutaneous absorption.

For the study of in-vitro skin penetration of candidate drugs, excised animal skin is frequently used as a replacement for human skin. Reconstructed human skin or epidermis equivalents have been proposed as alternatives. We compared the penetration properties of human, pig and rat skin with the Graftskin LSE (living skin equivalent) and the Skinethic HRE (human reconstructed epidermis) models using four topical dermatological drugs (salicylic acid, hydrocortisone, clotrimazole and terbinafine) with widely varying polarity. In agreement with published data, pig skin appeared as the most suitable model for human skin: the fluxes through the skin and concentrations in the skin were of the same order of magnitude for both tissues, with differences of at most two- or fourfold, respectively. Graftskin LSE provided an adequate barrier to salicylic acid, but was very permeable for the more hydrophobic compounds (e.g. about 900-fold higher flux and 50-fold higher skin concentrations of clotrimazole as compared to human skin), even more than rat skin. In the case of the Skinethic HRE, we found similar concentrations of salicylic acid as in human skin and an approximately sevenfold higher flux. In contrast, the permeation of hydrophobic compounds through the epidermal layer was vastly higher than through split-thickness human skin (up to a factor of about 800). To conclude, currently available reconstituted skin models cannot be regarded as generally useful for in-vitro penetration studies.

Animals↗