Mapping the human face: biophysical properties

Background: Facial skin exhibits unique biophysical properties that are distinct from skin belonging to other areas of the body. Small to large regional differences in biophysical properties between facial sites are observed. Technological advances in dermatological research allow a quantitative study of the biophysical qualities of the face and its relation to skin elsewhere. However, comprehensive studies examining inter‐regional variations using each of the six standard biophysical parameters have been few. We summarize findings on the biophysical parameters used to explore the human face as well as regional differences in skin reactivity to chemical irritants. Methods: We performed a literature search using Pubmed, Embase, Science Citations Index, and the UCSF's dermatological library on biophysical parameters and skin physiology pertaining to the human face. Results: Distinct regional differences in transepidermal water loss (TEWL), capacitance, blood flow, sebum, pH, and temperature were demonstrated in facial skin. However, studies cannot be compared with each other because each uses different anatomical sites, skin conditions, and measurement techniques. Intraregional differences in TEWL, sebum, and temperatures were observed on the cheeks and appeared to follow characteristic distribution patterns. Higher blood flow levels and skin temperatures were generally observed in areas with dense networks of blood vessels such as the nose and perioral region. Areas such as the forehead, nose, and chin consistently showed higher sebum casual levels, but variability in sebum levels between sites was also observed. The susceptibility of the face to hexyl nicotinate, sodium lauryl sulfate, and benzoic acid differed depending on location and age. Conclusion: Establishing a standardized biophysical profile of the human face will help to improve therapeutics, and further our understanding of differences in chemical reactivity and disease distribution. Future research necessitates standardization of the anatomical sites studied, sample size, and experimental protocols.     

Topical corticosteroids in psoriasis: strategies for improving safety

Corticosteroids are a mainstay of topical therapy for psoriasis. While efficacious and relatively safe when used carefully, the potential for side effects, notably skin atrophy and adrenal suppression, have been associated with excesses in potency, prolonged or widespread use. The International Psoriasis Council Working Group on Topical Therapy has reviewed the efficacy and safety of topical corticosteroids and recommends strategies for safe, long‐term use of these agents.     

Electron paramagnetic resonance: a new techniquein skin research

Electron paramagnetic resonance (EPR) spectra of nitroxide spin probes have been used for studying biological membranes and chemical‐membrane interaction. We have investigated the influence of surfactants on the intercellular lipid structure of cadaver stratum corneum and the possibility of EPR spectral measurements on the stripped stratum corneum utilizing cyanoacrylate resin, which might reflect the actual skin lipid conditions. Conclusion: EPR spectra are useful in evaluating the fluidity measurement of stratum corneum of cadaver skin and stripped stratum corneum.     

Flare-up reactions and desensitization from oral dosing in chromate-sensitive guinea pigs

Flare-up reactions were induced in potassium dichromate hypersensitive guinea pigs by a single oral dose of 55 mg/kg. This dose is systemically toxic and higher than the dose required to induce the same reactions in humans. A total oral dose of potassium dichromate of 90-115 mg/kg induced immunological unresponsiveness for at least 6 weeks. With limitations, the guinea pig model may be helpful in screening the hyposensitization capacity of different haptens dosed orally.     

Pathophysiology and management of sensitive skin: position paper from the special interest group on sensitive skin of the International Forum for the Study of Itch (IFSI)

The special interest group on sensitive skin of the International Forum for the Study of Itch previously defined sensitive skin as a syndrome defined by the occurrence of unpleasant sensations (stinging, burning, pain, pruritus and tingling sensations) in response to stimuli that normally should not provoke such sensations. This additional paper focuses on the pathophysiology and the management of sensitive skin. Sensitive skin is not an immunological disorder but is related to alterations of the skin nervous system. Skin barrier abnormalities are frequently associated, but there is no cause and direct relationship. Further studies are needed to better understand the pathophysiology of sensitive skin – as well as the inducing factors. Avoidance of possible triggering factors and the use of well-tolerated cosmetics, especially those containing inhibitors of unpleasant sensations, might be suggested for patients with sensitive skin. The role of psychosocial factors, such as stress or negative expectations, might be relevant for subgroups of patients. To date, there is no clinical trial supporting the use of topical or systemic drugs in sensitive skin. The published data are not sufficient to reach a consensus on sensitive skin management. In general, patients with sensitive skin require a personalized approach, taking into account various biomedical, neural and psychosocial factors affecting sensitive skin.     

Adjuvant perioperative portal vein or peripheral intravenous chemotherapy for potentially curative colorectal cancer: long-term results of a randomized controlled trial

Background and aims  The perioperative use of a single course adjuvant portal vein infusion chemotherapy in patients with potentially curable colorectal cancer has been shown to significantly improve overall survival but did not reduce the occurrence of liver metastases (SAKK 40/81) [Swiss Group for Clinical Cancer Research (SAKK) Lancet 345(8946):349–353, 1995]. The objective of the present prospective, three-arm randomized multicenter trial was to assess whether peripheral venous administration of adjuvant chemotherapy regimen based on 5-fluorouracil (5-FU) and mitomycin C decreases the occurrence of liver metastases as well as prolongs disease-free and overall survival. Materials and methods  Stages I–III colorectal cancer patients (n = 753) were randomized to receive either surgery alone (control arm), surgery plus postoperative portal venous infusion of 5-FU 500 mg/m² plus heparin given for 24 hours for seven consecutive days plus mitomycin C 10 mg/m² given on the first day (arm 2), or surgery and the same chemotherapy regimen administered by peripheral venous route (arm 3). Results  The 5-year disease-free survival for the three treatment groups were 65% (control group), 60% (portal vein infusion, hazard ratio 1.18, p = 0.23), and 64% (intravenous infusion, hazard ratio 1.04, p = 0.76); the 5-year overall survival was 72% (control group), 69% (portal vein infusion, hazard ratio 1.21, p = 0.2), and 74% (intravenous infusion, hazard ratio 1.03, p = 0.86), respectively. A significant accumulation of early deaths were observed in the portal vein infusion group (p = 0.015). Conclusions  The present prospective randomized multicenter trial provides compelling evidence that short-term perioperative chemotherapy does not improve disease-free and overall survival in patients with potentially curative colorectal cancer. In contrary, the chemotherapy regimen administered in the present investigation seems to have potentially harmful effects, a finding which should be carefully considered in the planning of future trials. Postoperative short-term administration of 5-FU plus mitomycin C either through portal infusion or a central venous catheter is not recommended for routine use in patients with potentially curable colorectal cancer. M. Lorenz deceased.