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At least 127 records · Page 7Linked to original sources

PubMed2002

Deep skin slough following skin traction for hip fractures.

INTRODUCTION: Elderly patients who fracture their hips are susceptible to complications associated with bed rest before surgery. In some institutions a skin traction device is used in order to relieve pain before surgery. The authors followed ten patients who developed severe (deep) skin slough and evaluated the relationship to the skin traction device. The need for use of a skin traction device is debated and the need for multidisciplinary treatment if this complication develops is emphasised. PATIENTS AND METHODS: All patients who had serious skin slough between January and December 2000 were evaluated. A serious skin slough was defined as any new and abrupt case of a full-thickness skin loss involving damage or necrosis of subcutaneous tissue, but not through the underlying fascia and not extending to underlying bone, tendon or joint capsule. Preoperative assessment including background illness and medications, the application of a skin traction device, the type of surgery that was performed, and complications were noted. RESULTS: Ten patients (nine females and one male) aged 76-90 years met the criteria of serious skin slough. The leading chronic illness was cardiovascular. Among these patients there were intertrochanteric fractures (n = 5), subcapital fractures (n = 4) and a subtrochanteric fracture (n = 1). In all patients a skin traction device was used. In seven out of the ten patients the skin slough occurred during or immediately after surgery. Other postoperative complications included uncontrolled glucose levels (> 130 mg/dl during fasting) (two cases) and urinary tract infections (two cases). The skin slough was treated with a daily wound care regimen by a trained nurse and included daily changing of wet dressings and application of Vaseline gauze. All patients were allowed immediate ambulation after the surgery and were discharged 9-15 days after the surgery. Although improvement of the slough was noted in all patients, none of them had fully recovered, and they had to continue treatment in outpatient clinics. DISCUSSION: The main goal of treatment in elderly patients who fractured their hips is to return them to their previous activities of daily living. A skin traction device, although useful for many of the patients, has the disadvantage of causing serious skin slough. This complication can interfere with the normal curve of rehabilitation and cause prolonged hospital stay. Whenever this complication is expected, the application of the skin traction device should be avoided. Moreover, careful handling of the patients by physicians, physiotherapists and nurses is mandatory. If this complication develops, vigorous multidisciplinary care is recommended.

Aged↗

PubMed2003

Reactivity of resident immunocytes in normal and prepsoriatic skin using an ex vivo skin-explant model system.

CONTEXT: While it is well known that both exogenous and endogenous stimuli can trigger appearance of psoriatic lesions, the initial cellular and molecular events mediated by immunocompetent cells normally resident in prepsoriatic (PN) skin are not well understood. Moreover, it is unclear whether there are any fundamentally important differences in the innate immune response of normal healthy skin (NN skin) versus PN skin. Since acute tissue responses to stimuli involve both resident cells and immunocytes recruited rapidly from circulation, it is difficult to discern the contribution of endogenous cells normally present in skin. OBJECTIVE: To solely characterize the reactivity of resident immunocytes using an experimental system. DESIGN: To probe the activation potential of resident immunocytes in NN (n = 18) and PN skin (n = 10), a short-term ex vivo organ culture system containing interleukin (IL)-2 was established and characterized. To mimic exogenous or environmental trigger factors, bacteria-derived superantigens and lipopolysaccharide were added to the skin-explant assays, whereas endogenous trigger factors were investigated using heat shock proteins. RESULTS: Using this skin-explant assay, both NN and PN skin gave rise to an expansion of various T-cell subsets, which could differentially produce various cytokines and a growth factor (keratinocyte growth factor), depending on the stimulus and source of skin. Bacterial superantigens were relatively potent inducers of interferon-gamma, and natural killer-T cells were observed proliferating from PN skin. CONCLUSIONS: Despite relatively few T cells normally residing in either NN or PN skin, initiation of skin explants from both sets of individuals in the presence of IL-2 triggered vigorous T-cell proliferation and cytokine/growth factor release. These results demonstrate the utility of this skin-explant assay system to further investigate quantitative and qualitative immune responses of NN and PN skin.

Adolescent↗

PubMed1992

Comparisons of different animal skins with human skin in drug percutaneous penetration studies.

The in vitro penetration of theophylline, sodium diclofenac and benzoic acid through artificial cellulose membrane and eight animal skins was investigated. The intact animal skins including stratum corneum (SC) and viable epidermis were taken from frog, snake with or without scales, nude mice, Sprague-Dawley rat, porcine and human prepuce and thigh skin. The results indicated that the penetration was fastest through cellulose membrane and frog skin and slowest through human prepuce and thigh skin. The snake skin with scales slowed down the penetration rate more significantly than the scaled skin. Benzoic acid was the fastest penetrant through all animal skins. The permeable behaviors of sodium diclofenac through SC and intact skin of snake, porcine and human were compared. In porcine, sodium diclofenac penetrated through SC at a rate 33 times higher than through intact skin, but in snake and human skin, the rate through SC was only 2.2 and 1.6 times higher than through intact ones. This implies that both viable epidermis and SC were the major rate limiting barriers in drug penetration. DSC thermograms and IR spectra showed that the SC of snake, porcine and human thigh were very similar in structure and components. The study suggests that snake skin, porcine skin and human prepuce skin could replace the human skin in in vitro drug penetration experiments.

Animals↗

PubMed2001

Modulation of skin collagen metabolism in aged and photoaged human skin in vivo.

To the best of our knowledge, no study has been conducted to date to directly compare the collagen metabolism of photoaged and naturally aged human skin. In this study, we compared collagen synthesis, matrix metalloproteinase-1 levels, and gelatinase activity of sun-exposed and sun-protected skin of both young and old subjects. Using northern blot analysis, immunohistochemical stain, and Western blot analysis, we demonstrated that the levels of procollagen type I mRNA and protein in photoaged and naturally aged human skin in vivo are significantly lower than those of young skin. Furthermore, we demonstrated, by northern blot analysis, that the procollagen alpha1(I) mRNA expression of photoaged skin is much greater than that of sun-protected skin in the same individual. In situ hybridization and immunohistochemical stain were used to show that the expression of type I procollagen mRNA and protein in the fibroblasts of photoaged skin is greater than for naturally aged skin. In addition, it was found, by Western blot analysis using protein extracted from the dermal tissues, that the level of procollagen type I protein in photoaged skin is lower than that of naturally aged skin. The level of matrix metalloproteinase-1 protein and the activity of matrix metalloproteinase-2 were higher in the dermis of photoaged skin than in naturally aged skin. Our results suggest that the natural aging process decreases collagen synthesis and increases the expression of matrix metalloproteinases, whereas photoaging results in an increase of collagen synthesis and greater matrix metalloproteinase expression in human skin in vivo. Thus, the balance between collagen synthesis and degradation leading to collagen deficiency is different in photoaged and naturally aged skin.

Adult↗

PubMed1999

Evaluation of skin viscoelasticity and anisotropy by measurement of speed of shear wave propagation with viscoelasticity skin analyzer.

Skin viscoelasticity was evaluated by a fast, noninvasive assay based on the measurement of the speed of elastic shear wave propagation in the skin by a new portable and user-friendly viscoelasticity skin analyzer. The range of speed of elastic shear wave propagation measured by viscoelasticity skin analyzer allows the evaluation of the stiffness of a wide spectrum of artificial materials as well as the viscoelasticity of skin of laboratory animals and human subjects. The directional nature of the measurement enables to monitor the anisotropy of the materials tested. The speed of elastic shear wave propagation was shown to have a positive correlation with the stiffness of the material tested. In symmetric contralateral areas of intact skin in rabbit ears, similar viscoelasticity and anisotropy were observed. Twenty-four hours after the induction of local edema by croton oil, skin stiffness and anisotropy were significantly increased. In healthy human subjects of both sexes significant variations in skin stiffness and anisotropy were observed in three different skin areas along the forearms, but the speed of elastic shear wave propagation was similar in the symmetric contralateral areas. Age (17-65 y) seemed to have a limited effect on the viscoelasticity of the forearm skin. Hydrating creams decreased the stiffness of the forearm skin for only approximately 3 h. The stiffness and anisotropy of the skin of the breasts in female volunteers (20-86 y) increased with age, but the speed of elastic shear wave propagation was similar in symmetric contralateral areas in the same individuals. Based on these results, we propose the application of the viscoelasticity skin analyzer in experimental and clinical practice for quantitative evaluation of skin condition.

Administration, Topical↗

PubMed1993

Sunlight, keratotic skin lesions and skin cancer in renal transplant recipients.

In a retrospective follow-up study, 36 renal transplant recipients with, and 101 without, skin cancer, who had received their first transplant before January 1981 and who were still alive with a functioning graft on 1 August 1989, were assessed to determine the risk of non-melanoma skin cancer in relation to exposure to sunlight during childhood and adolescence. The contribution of the number of keratotic skin lesions to the skin cancer risk was also assessed. The estimated relative risks (odds ratios) of skin cancer in relation to exposure to sunlight and the presence of keratotic skin lesions were calculated by maximum likelihood estimation in a logistic model. The majority of skin cancers and keratotic skin lesions were confined to sun-exposed skin. After adjustment for possible confounding variables, the odds ratios of skin cancer for moderate and high cumulative life-time exposure to sunlight, respectively, compared with low exposure, were 2.4 (95% confidence interval [CI] 0.64-9.3) and 47.6 (95% CI 5.4-418). Exposure to sunlight before the age of 30 contributed more to the risk of developing skin cancer later in life than exposure after the age of 30. No association was found between cumulative life-time exposure to sunlight and the number of keratotic skin lesions. Nevertheless, these lesions behaved as a strong independent risk factor in the development of skin cancer. The adjusted odds ratio of skin cancer for 50-99 lesions compared with < 50 lesions was 4.5 (95% CI 1.1-18.2); the adjusted odds ratio for > or = 100 lesions compared with < 50 lesions was 20.8 (95% CI 5.3-81.7).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed2004

Increased risk of skin cancer associated with the presence of epidermodysplasia verruciformis human papillomavirus types in normal skin.

BACKGROUND: Human papillomaviruses (HPVs) are found in normal skin and in benign and malignant skin conditions. Epidermodysplasia verruciformis (EV) HPV types are those most plausibly linked to the development of squamous cell carcinomas of the skin. OBJECTIVES: To assess the risk of nonmelanoma skin cancer (NMSC) associated with the presence of EV HPV in normal skin in immunocompetent (IC) individuals and renal transplant recipients (RTRs). METHODS: Using a degenerate and nested polymerase chain reaction technique, HPV DNA was sought in 124 normal skin samples from sun-exposed and nonsun-exposed sites, from 39 IC individuals and 38 RTRs, both with and without NMSC. Data were analysed using the Mantel-Haenszel test and by logistic regression analysis. RESULTS: HPV DNA was detected in 58/67 (87%) and 20/57 (35%) samples from renal transplant and IC patients, respectively. There was no difference in either the prevalence or spectrum of HPV types found in sun-exposed and nonsun-exposed normal skin. However, there was significant association between NMSC and the presence of EV HPV DNA. Multivariate analysis provided an odds ratio of 6.41 (95% confidence interval 1.79-22.9) for the association of EV HPV DNA in normal skin (irrespective of site) and NMSC status, even after stratifying for patient group and adjusting for the clustering effect of multiple sampling. Conversely, there was no association between skin cancer status and the presence of cutaneous or mucosal HPV types in either sun-exposed or nonsun-exposed skin. CONCLUSIONS: HPV DNA is widespread in normal adult skin, particularly in transplant patients. In our study, the presence of EV but not cutaneous HPV DNA in normal skin was significantly associated with NMSC status and may prove to be of predictive value for skin cancer risk. These data provide reason to focus on EV HPV types as causal agents in skin cancer.

Adult↗

PubMed2004

Ovariectomy is sufficient to accelerate spontaneous skin ageing and to stimulate ultraviolet irradiation-induced photoageing of murine skin.

BACKGROUND: Wrinkling and sagging of the skin during photoageing is physiologically associated with diminished elasticity, which can be attributed to increased fibroblast-derived elastase activity. This degrades the dermal elastic fibres needed to maintain the three-dimensional structure of the skin. We previously reported that ovariectomy accelerates ultraviolet (UV)B-induced wrinkle formation in rat hind limb skin by altering the three-dimensional structure of elastic fibres. OBJECTIVES: In this study, we used hairless mice to assess the effects of ovariectomy with or without chronic UVA or UVB radiation on sagging and wrinkling of skin, on the elasticity of skin, as well as on matrix metalloproteinase activities in the skin. METHODS: Ovariectomies or sham operations were performed on 6-week-old female ICR/HR hairless mice. RESULTS: Even in the ovariectomy group without UV irradiation, the skin elasticity was significantly decreased during the 3-13 weeks after ovariectomy, which was accompanied by a significant increase in elastase activity in the skin. After UVA or UVB irradiation, skin elasticity was significantly decreased to a greater extent in the ovariectomy group than in the sham operation group, and this was accompanied by a reciprocal increase in elastase activity but not in the activities of collagenases I or IV in the skin. Consistent with the decreased skin elasticity, UVA irradiation for 12 weeks elicited more marked sagging in the ovariectomy group than in the sham operation group. UVB irradiation for 12 weeks also induced more marked wrinkle formation in the ovariectomy group than in the sham operation group. CONCLUSIONS: These results suggest that ovariectomy alone is sufficient to accelerate skin ageing and to increase UV sensitivity, which results in the further deterioration of the skin and photoageing, and may account for the accelerated skin ageing seen in postmenopausal women.

Animals↗

PubMed1980

Localization of the defect in skin diseases analyzed in the human skin graft-nude mouse model.

Human skin can be grown away from its donor for prolonged periods as grafts on congenitally athymic "nude" mice. This system has been used to analyze the defect in several skin diseases, specifically to localize the site of the defect to the skin itself or to the epidermal or dermal components of the skin. In order to validate the use of the nude mouse human skin graft system in the analysis of skin defects, we have demonstrated that a systemic metabolic defect which involves the skin, namely essential fatty acid deficiency, can be differentiated from a defect residing primarily in the skin itself. Skin-marker systems have been developed for use with the nude mouse-human skin graft model to document the identity of human skin grafts and epidermal and dermal components of the grafts after prolonged periods of growth on the nude athymic mice. Y-body, a small fluorescent segment of the Y-chromosome seen in interphase cells, is used as a sex marker and serves to distinguish sex differences between the graft and the mouse recipient or between skin components of the graft. The ABH "blood-group" antigens are present on differentiated epidermal cell surfaces and identify the grafted epidermis according to the blood groups of the donor. In previous studies, lamellar ichthyosis was shown to be well maintained after prolonged periods of growth on nude athymic mice, indicating that the defect in this disease resides in the skin itself. Recombinant grafts composed of normal and lamellar ichthyosis epidermis and dermis further localize the defect to lamellar ichthyosis epidermis. Psoriasis is well maintained on the nude mouse-skin graft model. The epidermal hyperplasia and hyperproliferative epidermal cell kinetics of psoriasis are manifested in the grafts of active psoriasis maintained for prolonged periods on the nude mice, but the inflammatory component of psoriasis is absent. Recombinant graft studies utilizing normal and psoriatic epidermis and dermis demonstrate psoriasis only in recombinant grafts composed of both psoriatic epidermis and dermis. These studies indicate that psoriasis requires both psoriatic epidermis and dermis for its expression.

ABO Blood-Group System↗

PubMed1995

Objective assessment of the skin of children affected by atopic dermatitis: a study of pH, capacitance and TEWL in eczematous and clinically uninvolved skin.

In order to obtain objective data on skin functions in subjects with atopic dermatitis (AD), according to the different phases of the disease, we evaluated the skin of children with AD instrumentally and compared it to that of healthy subjects of the same age group. One hundred patients, aged 3 to 12, and 21 healthy children were studied by means of measurements of pH, capacitance and transepidermal water loss (TEWL) at 8 different skin sites. At the moment of the investigation 55 children out of 100 presented skin lesions on at least one of the assessed skin areas, whereas 45 had been free from eczema for at least 1 month. Considering all skin sites together, significant differences were found between mean values of pH, capacitance and TEWL of eczematous skin, both in respect to those referring to apparently healthy skin in the same patients and in respect to the skin of control subjects. Moreover, TEWL, pH and capacitance values referring to uninvolved skin of AD patients significantly differed from those of healthy subjects. Finally, when values referring to patients with skin lesions and to patients without lesions were separately considered, significant differences concerning the parameters of uninvolved skin were observed. These data show that, in subjects with AD, skin functions undergo fluctuations according to the phase of the disease and support the hypothesis that the presence of active eczema determines an impairment of the barrier of uninvolved skin, even at sites far from active lesions.

Child↗

PubMed1998

Interdependence of eye and hair colour, skin type and skin pigmentation in a Caucasian population.

Eye colour, hair colour and skin colour are important risk factors for malignant melanoma and non-melanoma skin cancers. There are few studies in which the distribution of these pigmentary factors in risk populations has been assessed. The purpose of this study was to investigate the prevalence of the major eye and hair colours and the distribution of skin types and skin pigmentation in a Caucasian population. In 892 Danish Caucasians, eye colour, hair colour and skin type were assessed and facultative and constitutive skin pigmentation were measured objectively using skin reflectance spectroscopy. Blue eye colour and blond hair colour and skin type II were the most frequent (60%, 67% and 33% of subjects, respectively). All four major eye colours and four major hair colours (with the exception of red hair colour) were found within skin types I-IV and we could not predict the skin type or the constitutive skin pigmentation. Skin type could not be taken to classify individuals reliably according to their facultative or constitutive skin pigmentation.

Adolescent↗

PubMed2003

Early skin-to-skin contact for mothers and their healthy newborn infants.

BACKGROUND: Early skin-to-skin contact involves placing the naked baby prone on the mother's bare chest at birth or soon afterwards (< 24 hour). This could represent a 'sensitive period' for priming mothers and infants to develop a synchronous, reciprocal, interaction pattern, provided they are together and in intimate contact. Routine separation shortly after hospital birth is a uniquely Western cultural phenomenon that may be associated with harmful effects including discouragement of successful breastfeeding. OBJECTIVES: To assess the effects of early skin-to-skin contact on breastfeeding, behavior, and physiology in mothers and their healthy newborn infants. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group and Neonatal Group trials registers (December 2002), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2002), MEDLINE (1976 to 2002). SELECTION CRITERIA: Randomized and quasi-randomized clinical trials comparing early skin-to-skin contact with usual hospital care. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. We contacted study authors for additional information. We collected adverse effects information from the trials. MAIN RESULTS: Seventeen studies, involving 806 participants, were included. We found statistically significant and positive effects of early skin-to-skin contact on breastfeeding at one to three months postbirth (odds ratio (OR) 2.15, 95% confidence interval (CI) 1.10 to 4.22), breastfeeding duration (weighted mean difference (WMD) 41.99, 95% CI 13.97 to 70.00), maintenance of infant temperature in the neutral thermal range (OR 12.18, 95% CI 2.04 to 72.91), infant blood glucose (WMD 11.07, 95% CI 3.97 to 18.17), infant crying (OR 21.89, 95% CI 5.19 to 92.30) and summary scores of maternal affectionate love/touch (SMD 0.73, 95% CI 0.36 to 1.11) during an observed breastfeeding within the first few days postbirth. We found no statistically significant benefit of early skin-to-skin contact for other major clinical variables: breastmilk maturation, maternal chest circumference, infant heart rate. REVIEWER'S CONCLUSIONS: Limitations included the methodological quality of the studies, variations in the implementation of the intervention and outcome variability. Early skin-to-skin contact appears to have some clinical benefit especially regarding breastfeeding outcomes and infant crying and has no apparent short or long-term negative effects. Further investigation is recommended. To facilitate meta-analysis of the data, future research in this area should involve outcome measures consistent with those used in the studies included here. Published reports should also clearly indicate if the intervention was skin-to-skin contact and include means, standard deviations and exact probability values.

Breast Feeding↗

PubMed1995

Serial fluorometric assessments of skin perfusion in isolated perfused human skin flaps.

The applicability of serial skin surface fluorometry for repeated assessments of skin flap perfusion was investigated using the isolated perfused human transverse paraumbilical (TP) skin flap model. The flow rate, perfusion pressure and skin surface temperature were kept constant in seven human TP skin flaps and a low dose of fluorescein (3 x 10(-5) M) was used for each assessment. It was observed that the mean values for total dye fluorescence measured by a fluorometer and the maximum distance of perfusion estimated by dye fluorescein index remained consistent in five repeated assessments at 15 min interval. The variation in the maximum distance of perfusion within each TP skin flap over 5 repeated assessments was also relatively small, as judged by the mean coefficient of variation (6.1%; SEM 0.4%). Furthermore, a highly significant correlation between microsphere (15 microns) radioactivity index and dye fluorescence index was observed at corresponding locations in these seven TP skin flaps (r = 0.81; p < 0.001, n = 75). Taken together, these observations indicate that serial skin surface fluorometry provided consistent repeated assessments of skin perfusion in human skin flaps in vitro and the dye fluorescence index provided a consistent assessment of skin perfusion distance along the length of the TP skin flap. These observations lead us to speculate that critical (threshold) dye fluorescence index determined at various postoperative time points should be useful for prediction of skin viability in clinical skin flaps; thus, a clinical investigation is recommended.

Acetylcholine↗

PubMed2006

Skin cancer in skin of color.

UNLABELLED: Skin cancer is less common in persons with skin of color than in light-skinned Caucasians but is often associated with greater morbidity and mortality. Thus, it is crucial that physicians become familiar with skin cancer in persons of color so as to maximize the likelihood of early detection of these tumors. In dark-skinned ethnic groups, squamous cell carcinoma is most common; squamous cell carcinoma and melanoma usually occur on nonsun-exposed sites; and ultraviolet radiation is not an important etiologic factor for skin cancer with the exception of basal cell carcinoma. Races of intermediate pigmentation, such as Hispanics and Asians, share epidemiologic and clinical features of dark-skinned ethnic groups and Caucasians. Skin cancers pose a significant risk in skin of color and clinicians should focus on preventive measures in these groups such as regular skin exams, self-examination, public education, and screening programs. LEARNING OBJECTIVE: At the completion of this learning activity, participants should be familiar with the epidemiology and unique clinical features of skin cancer in skin of color and be aware of strategies to prevent skin cancer in skin of color.

Humans↗

PubMed1999

Vaccination with irradiated cercariae of Schistosoma mansoni preferentially induced the accumulation of interferon-gamma producing T cells in the skin and skin draining lymph nodes of mice.

Cytokine response to schistosomula of Schistosoma mansoni was evaluated in the skin of mice during the initial 72 h following infection. These studies showed a significant increase in the levels of IL-4 and IL-10 message in the skin in areas of cercarial penetration. The IL-4 message was detectable in the skin as early as 8 h after infection and the message for IL-10 appeared from 16 h after infection. However, mRNA for IFN-gamma was undetectable in the skin samples for up to 72 h after infection with normal cercariae. In sharp contrast, vaccination with irradiated cercariae induced IFN-gamma and IL-2 responses in the skin within 24 h. Analysis of the cytokine profile of cells isolated from the skin during these early time points showed that T cells are probably not a source of IL-4 or IL-10 in the skin of mice infected with normal cercariae. However, in vaccinated animals, the majority of the IFN-gamma is derived from skin-residing T cells. In vaccinated animals, responses in the skin were mirrored in the skin-draining lymph nodes as well. Analysis of the CD4/CD8 ratio showed a significant decrease in the skin following vaccination suggesting an increase in CD8+ cells. Interestingly however, when vaccinated animals were challenged with normal cercariae, there was a significant reduction in IFN-gamma response in the skin and its draining lymph nodes. These results show that vaccination with irradiated cercariae of S. mansoni, preferentially induce the accumulation of IFN-gamma producing T cells in the skin and skin-draining lymph nodes of mice.

Animals↗

PubMed2000

A human skin equivalent model that mimics the photoproduction of vitamin D3 in human skin.

A human skin equivalent was prepared by culturing human keratinocytes on the surface of nylon filtration meshes containing human skin fibroblasts and by growing the epidermal cells at the air-liquid interface. This human skin equivalent model was used to mimic the photoproduction of vitamin D3 in human skin. It was found that the concentration of 7-dehydrocholesterol and its photoconversion to previtamin D3 and its subsequent thermal isomerization to vitamin D3 in the human skin equivalent was essentially identical to that of human skin. The 7-dehydrocholesterol content in the skin equivalent and human skin was 2187 +/- 296 and 2352 +/- 320 ng/cm2, respectively. The percentage of the major photoproducts of 7-dehydrocholesterol in the skin equivalent following ultraviolet B radiation (0.5 J/cm2) was 35% pre-vitamin D3, 29% lumisterol, and 6% tachysterol; 30% remained as 7-dehydrocholesterol. Similarly, in human skin they were 36%, 29%, 7%, and 28%, respectively. After incubation at 37 degrees C for 30 min, 11% and 12% of the previtamin D3 had thermally isomerized to vitamin D3 in the skin equivalent and human skin. In conclusion, compared with cultured keratinocytes or fibroblasts, the human skin equivalent model provides a superior in vitro system that better mimics the physiology and biochemistry of the photosynthesis of vitamin D3 in human skin.

Cholecalciferol↗

PubMed2004

[Gene expression of angiogenesis-related factors in fetal skin at different developmental stages and childhood skin].

OBJECTIVE: To explore the change in gene expression of angiogenesis-related factors vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1), acid fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF), in fetal skin at different developmental stages and children skin and their potential biological significances. METHODS: Fetal skin samples of human embryo were obtained from spontaneous abortion at different gestational ages ranging from 13 to 32 weeks, and children skin specimens were collected from child patients (4-12 years) undergoing plastic surgery. After morphological characteristics of skin at different developmental stages were defined histologically gene expressions of VEGF, Ang-1, aFGF and bFGF were examined with reverse transcription-polymerase chain reaction analysis (RT-PCR). RESULTS: The trend of changes in gene expression of VEGF, Ang-1, aFGF and bFGF was not same for different skin specimens at various developmental stages. In early gestational fetal skin, genes of VEGF and Ang-1 were strongly expressed, while in late gestational and childhood skins, gene expressions of VEGF and Ang-1 were apparently decreased. In skin of middle gestational stage, the level of aFGF gene expression was highest, and then it was progressively reduced. In childhood skin, this gene was weakly expressed. In marked contrast, the contents of transcripts of bFGF showed no substantial change in fetal skin at different developmental stages, whilst the mRNA content of bFGF was significantly decreased in childhood skin. CONCLUSION: VEGF, Ang-1, aFGF and bFGF might be involved in regulating angiogenesis in skin from fetuses of different gestational stages and children. The relative increase in gene transcription of VEGF and Ang-1 in younger fetal skin might be one of the reasons why cutaneous cells proliferate rapidly and the wounds heal without scar.

Angiogenic Proteins↗

PubMed1990

Energy conservation during skin-to-skin contact between premature infants and their mothers.

The effects of skin-to-skin contact on three indexes of energy expenditure: heart rate, activity level, and behavioral state, were examined in a pilot study. It was hypothesized that skin-to-skin contact, because of its soothing effects, would increase sleep, lower activity level, and reduce heart rate. Eight healthy preterm infants in a neonatal intensive care unit, who had reached 34 to 36 weeks gestation, experienced one session of skin-to-skin contact for an interfeeding interval. Observations were made once each minute using continuous videotape throughout three consecutive interfeeding intervals (before, during, and after skin-to-skin contact). Significant treatment effects were found by repeated-measures analysis of variance for behavioral state and activity level; pair-wise comparisons showed that quiet sleep frequency was significantly increased and activity level reduced during skin-to-skin contact. Infants had longer durations of quiet sleep during skin-to-skin contact. The Pearson product-moment correlation between heart rate and behavioral state was robust and generally linear, supporting use of heart rate as a measure of energy expenditure in these subjects. The findings suggest that skin-to-skin contact is a simple, cost-effective intervention that reduces activity and state-related energy expenditure.

Adult↗