'Nosing Around' the human skin: What information is concealed in skin odour?

In today's world, natural body odour is mostly considered as being unpleasant and combated by intensive cleansing, deodorants and perfumes. However, there is evidence that volatile body compounds provide the recipient with important information. Here, we present the chemical identity of odorous compounds derived from odourless precursors within sweat and sebum. Moreover, distinct volatile markers may be relevant for the clinical diagnosis of disease. Interestingly, ageing seems to correlate with the appearance of specific compounds that convey the so-called old man smell. Finally, it is discussed if human skin odour has the quality to act as pheromone transmitting information between individuals in terms of major histocompatibility complex type or reproductive status.     

The antiproteolytic compound α 2 in human skin

Summary Monoclonal antibodies recognizing the antiproteolytic compound ₂-macroglobulin (MG) were used for immunohistological studies on normal human skin. MG-specific immunoreactivity was found to be localized to the papillary dermis and to be concentrated in the region of the epidermodermal junction. In view of these findings and the possible involvement of proteolytic enzymes and their inhibitors in blister formation, we asked whether MG occurs in the fluid of experimentally induced blisters. MG was identified (by western-blotting) and quantified (by a monoclonal antibody based enzyme immunoassay) in the fluid of experimentally induced suction blisters. Taken together, MG is present in such blister fluid in concentrations 6 times lower than in serum, but still in an antiproteolytic range. These findings allow suggestion of a possible role for the antiproteolytic compound MG in blister formation.     

Β-Adrenergic receptors in psoriasis: evidence for down-regulation in lesional skin

Lesional psoriatic skin displays reduced responsiveness to -adrenergic stimulating agents. To elucidate whether the receptor protein itself is responsible for this, lesional and non-lesional psoritatic skin was investigated ex vivo for maximal -adrenergic binding density (B _max) and -adrenergic binding affinity (K _D). Epidermal crude membrane homogenates (ECMH) were prepared from split-thickness skin biopsies and saturated with the lipophilic -adrenergic antagonist (—)-¹²⁵I-iodocyanopindolol (ICYP) as radioligand. Specific binding was saturable and Scatchard transformation of the binding data revealed a homogeneous class of -adrenergic receptors in all nine experiments. The maximal -adrenergic binding density was significantly less in lesional than in non-lesional psoriatic skin (B _max=49.7 ± 7.2 fmol/mg protein vs. 67.1 ± 2.2 fmol/mg protein, n=9, P<0.05). The binding affinity was similar in lesional and in non-lesional skin (K _D=9.0 ± 1.5 pmol/l vs. 8.0 ± 0.9 pmol/l). These results could at least partially explain the reduced responsiveness of the -adrenergic system in lesional psoriatic skin seen after stimulation with -adrenergic agonists.     

Helium–neon laser improves skin repair in rabbits

Abstract

The purpose of this study was to evaluate the influence of helium–neon laser on skin injury in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral skin damage in leg. Helium–neon laser light, at a fluence of 6?J∕cm² and wavelength of 632.8?nm, was applied on the left legs (laser group). The right leg lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections. The results showed little infiltration of inflammatory cells, with proliferation of fibroblasts forming a few fibrous connective tissue after 1 week post-injury. The lesion on the 3rd week was characterized by granulation tissue, which formed from proliferated fibrous connective tissue, congested blood vessels and mild mononuclear cell infiltration. On the 5th week, it was observed that debris material surrounded by a thick layer of connective tissue and dense collage, fibroblasts cells present in the dermis covered by a thick epidermal layer represented by keratinized epithelium. Taken together, our results suggest that helium–neon laser is able to improve skin repair in rabbits at early phases of recovery.     

Homocysteine may accelerate skin aging: a new chapter in the biology of skin senescence?

Skin aging has received tremendous attention in recent years by both scientists and the lay public. This article reviews the evidence that homocysteine, an intermediary sulfhydryl-containing amino acid implicated in atherosclerosis, can accelerate skin aging and the aging of internal organs (universal aging).     

How fast are UV-dimers repaired in human skin DNA in situ?

Sheehan et al (2002) published a paper on UV-dimers in human skin and their repair with contradictions in their own data. In one experiment they applied two doses, 0.65 and 2 MED, but the apparent dimer levels, measured by a immunohistochemical technique, only increased in skin of type II (Fig 2a). The authors offered as explanation that the level of DNA damage would saturate. The dimer levels reached are at around 1 dimer per 1 million nucleotides, and there has been no evidence for saturation when a quantitative postlabeling technique has been used (Bykov et al, 1998). There is no reason for saturation until most of the thydmidyl-thymidine positions would be occupied in DNA, which, based on literature with other intrastrand cross-linkers, would require dimer levels 1 : 100 (F?rsti et al, 1989), or 10,000 times higher levels of dimer than that obtained by an irradiation at a MED dose.     

How much skin protection cream is actually applied in the workplace? Determination of dose per skin surface area in nurses

Background. Skin protection creams (PCs) are used in the occupational setting to prevent irritant hand dermatitis. However, so far, the actual amounts of PC applied and the resulting dose per area unit on hands at work have not been a matter of systematic investigation. The quantities used in experimental studies investigating the efficacy of PCs range between 4 and 25 mg/cm². Objectives. To develop a practical and accurate method to analyse the actual consumed quantities of PCs at workplaces in relation to hand surface area. Methods. Thirty‐one hospital nurses without hand eczema were provided with a sample PC in special monitoring tubes with Medication Event Monitoring Systems (MEMS TrackCaps^®; Aardex Ltd, Zug, Switzerland), and used the product over 5 working days as usual. The consumption was calculated by weighing of the tubes and analysis of the application frequency, and related to the individual calculated hand surface area. Results. The mean PC dose applied was 0.97 ± 0.6 mg/cm². Conclusions. The amounts of PC applied by hospital nurses were significantly lower than the amounts that have been used in experimental studies. The method appears to be suitable for use in different in occupational settings. Further investigations are needed to gain realistic insights into consumers' attitudes regarding PCs.     

Sunscreens inadequately protect against ultraviolet-A-induced free radicals in skin: implications for skin aging and melanoma?

Sunscreens are employed to mitigate the adverse effects of sunlight on skin but are primarily designed to prevent ultraviolet-B-associated burning and damage. The increasingly recognized role of ultraviolet A in aging, and possibly melanoma, highlights the need to include ultraviolet A screens; however, validation remains difficult. We have used a novel method to establish the efficacy of sunscreens, by measuring ultraviolet-A-induced free-radical production (thought to contribute towards ultraviolet-A-related aging and malignant change). Electron spin resonance spectroscopy was used to detect free radicals directly in human Caucasian skin during irradiation with levels of ultraviolet comparable to solar intensities. Using this system the protection afforded by three high factor sunscreens (sun protection factor 20+) that claim ultraviolet A protection was examined. Each sunscreen behaved similarly: at recommended application levels (> or = 2 mg per cm2) the ultraviolet-induced free radicals were reduced by only about 55%, and by about 45% at 0.5-1.5 mg per cm (0.5 mg per cm2 reported for common usage). A "free-radical protection factor" calculated on the basis of these results was only 2 at the recommended application level, which contrasts strongly with the erythema-based sun protection factors (mainly indicative of ultraviolet B protection) quoted by the manufacturers (20+). The disparity between these protection factors suggests that prolonged sunbathing (encouraged by use of these creams) would disproportionately increase exposure to ultraviolet A and consequently the risk of ultraviolet-A-related skin damage.     

Squamous cell carcinoma in situ in skin: what does it mean?

Squamous cell carcinoma in situ (SCCIS) is a frequently reported diagnosis by pathologists. The dermatologists bases their management of the patient on this diagnosis. However, SCCIS can be seen in a variety of clinical situations. The pathologic diagnosis of SCCIS must be correlated with clinical data to arrive at a correct diagnosis and therefore appropriate management of the patient.     

Can the skin smear examination in NLEP be reconsidered?

Slit and skin smear examination is an important laboratory test which was made optional in the NLEP. In a laboratory managed by LEPRA Society, this test was provided to voluntary reporting cases and those referred by the general health service institutions of the area. Total cases tested were 1180, out of which 152 (12.9%) were positive. Of the 152 smear reports, 121 were from Koraput district and constitute the sample for this study. Regarding the spread of site wise highest BI, 56% cases had BI of 3.1+ to 6+. Of the 121 cases, 112 (92.6%) cases completed 12 doses of MDT. Seventy patients, from whom detailed information was collected by personal contact, responded well to MDT resulting in regression of lesions. Out of them, 46 cases had repeat smear showing negative smear in 39% and decline of 81 in the rest of cases. There are 16 contact cases with 2 family clusters. A rough block-wise mapping showed 4 strata with a dense clustering in the urban area where the laboratory facility is available. The probable reasons for uneven distribution of cases and causes for late diagnosis were discussed. The study reflects the leprosy problem in urban pockets which high infection pool. Together these two factors remain unexposed due to winding up of smear labs and pose a potential threat to elimination. The paper also emphasized on the reasons for past failure of the test along with suggestions to revive this facility with minor modifications.     

Expression of the collagen VI α5 and α6 chains in normal human skin and in skin of patients with collagen VI-related myopathies

Collagen VI is an extracellular matrix protein with critical roles in maintaining muscle and skin integrity and function. Skin abnormalities, including predisposition to keratosis pilaris and abnormal scarring, were described in Ullrich congenital muscular dystrophy (UCMD) and Bethlem myopathy (BM) patients carrying mutations in COL6A1, COL6A2, and COL6A3 genes, whereas COL6A5, previously designated as COL29A1, was linked to atopic dermatitis. To gain insight into the function of the newly identified collagen VI α5 and α6 chains in human skin, we studied their expression and localization in normal subjects and in genetically characterized UCMD and BM patients. We found that localization of α5, and to a lesser extent α6, is restricted to the papillary dermis, where the protein mainly colocalizes with collagen fibrils. In addition, both chains were found around blood vessels. In UCMD patients with COL6A1 or COL6A2 mutations, immunolabeling for α5 and α6 was often altered, whereas in a UCMD and in a BM patient, each with a COL6A3 mutation, expression of α5 and α6 was apparently unaffected, suggesting that these chains may substitute for α3, forming α1α2α5 or α1α2α6 heterotrimers.     

What is the role of mitochondrial dysfunction in skin photoaging?

Skin ageing is a complex process involving both internal and external factors, which leads to a progressive loss of cutaneous function and structure. Solar radiation is the primary environmental factor implicated in the development of skin ageing, and the term photoaging describes the distinct clinical, histological and structural features of chronically sun‐exposed skin. The changes that accompany photoaging are undesirable for aesthetic reasons and can compromise the skin and make it more susceptible to a number of dermatological disorders. As a result, skin ageing is a topic that is of growing interest and concern to the general population, illustrated by the increased demand for effective interventions that can prevent or ameliorate the clinical changes associated with aged skin. In this viewpoint essay, we explore the role that mitochondria play in the process of skin photoaging. There is continuing evidence supporting the proposal that mitochondrial dysfunction and oxidative stress are important contributing factors in the development of skin photoaging. Further skin‐directed mitochondrial research is warranted to fully understand the impact of mitochondrial status and function in skin health. A greater understanding of the ageing process and the regulatory mechanisms involved could lead to the development of novel preventative interventions for skin ageing.     

What can we learn about skin of color in dermatopathology?

As the US population becomes increasingly diverse, more patients of color seek dermatologic care and often have concerns that are unique to their skin color. Therefore, it is critically important that the knowledge gap in skin of color dermatology be urgently addressed. In addition to addressing the clinical gap in recognizing dermatologic disease in patients of color, the role of dermatopathology in bridging this gap remains unaddressed. Given the impact that skin color can have on the presentation and subsequent management of dermatologic diseases, understanding the current knowledge of the unique structural and histologic characteristics in skin of color may help give us insight on the role skin color should play in histopathologic diagnosis. In this paper, we bring insights into the role dermatopathology plays in addressing our knowledge of cutaneous disease in patients with skin of color. After we highlight issues to consider, we can begin to identify gaps in knowledge that still exist within dermatopathology that need to be addressed to ensure patients of all backgrounds receive equitable dermatologic care.     

Ultrastructural observations of skin lesions in MRL mice —dermoepidermal junction

Summary The MRL-lpr/lpr (MRL/1) mouse, a new animal model for the study of human systemic lupus erythematosus (SLE), shows characteristic skin manifestations in addition to several systemic autoimmune phenomena. The ultrastructural changes observed in the dermoepidermal junction (DEJ) and in the uppermost dermis were: (1) infolding of the DEJ; (2) deformities of the basal lamina, — partial disappearance, thickening, hanging down, duplication, and separation from the basal cell membrane; (3) basal laminalike dense material in the uppermost dermis and increased anchoring fibrils; (4) particles composed of circulated half-desmosomes between the basal cells and the basal lamina, and in the uppermost dermis with or without an enclosing basal lamina; (5) cell processes of the basal cells; and (6) invagination of the basal lamina in the basal cells. Most of these findings were similar to the ultrastructural changes observed in the skin lesions of human SLE. The skin eruptions of MRL/l mice might be a new aid in the investigation of the pathogenesis of the skin lesions of human SLE.This is the third part of a series of papers entitled pathogénesis of lupus dermatoses in autoimmune mice.     

Should the skin cancer examination be taught in medical school?

BACKGROUND: The fact that thin melanomas are associated with a greater than 95% survival rate, while later, more deeply invasive melanomas have a 5-year survival rate of less than 10%, demonstrates the potential personal and public health impact of early detection. The majority of patients with skin lesions are seen by nondermatologists who infrequently counsel patients about skin cancer prevention or perform a complete skin examination as part of routine care. We documented the antecedents of physician practice by evaluating medical students' observation, training, performance, and self-reported skill level for the skin cancer examination and sun protection counseling. METHODS: Surveys were administered and completed in classrooms and student workshops in each of the 4 medical school years during the spring of 1996 and 1997. We concentrate our analysis on the graduating fourth-year students. RESULTS: Of the 302 fourth-year students enrolled at Boston University School of Medicine, Boston, Mass, in 1996 and 1997, 223 (74%) completed surveys. Among fourth-year students, 52% rated themselves as unskilled in skin cancer examinations. Twenty-eight percent of fourth-year students had never observed a skin cancer examination, 40% had received no training, and 35% had never practiced the examination. However, fourth-year students reporting at least 1 opportunity to observe, train, or practice an examination were 3 times as likely to report themselves as moderately to very skilled as students without such opportunities. CONCLUSION: If medical student training rates for the skin cancer examination are equally low elsewhere, as is likely, the present data suggest that even brief additions to the current curriculum, integrated into systems teaching, would augment student exposure and likely boost student skill levels.