Study of skin–fabric interactions of relevance to decubitus: friction and contact-pressure measurements

Background/purpose: Prolonged pressure as well as friction and shear forces at the skin–textile interface are decisive physical parameters in the development of decubitus. The present article describes the contact phenomena at the skin–textile interface and the development of a purpose-built textile friction analyser (TFA) for the tribological assessment of skin–fabric interactions, in connection with decubitus prevention.
Methods: Interface pressure distributions were recorded in the pelvic and femoral regions between supine persons and a foam mattress. Fabrics made of various natural and synthetic yarns were investigated using the TFA. A vertical load of 7.7 kPa was applied to the swatches, simulating high interface pressures at the skin–fabric interface and clinical conditions of bedridden persons. Fabrics were rubbed in reciprocating motions against a validated skin-simulating material to determine static as well as dynamic friction coefficients (COFs).
Results: Maximum contact pressures ranged from 5.2 to 7.7 kPa (39–58 mmHg) and exceeded the capillary closure pressure (32 mmHg) in all investigated bedding positions. For both COFs, a factor of 2.5 was found between the samples with the lowest and highest values. Our results were in a similar range to COFs found in measurements on human skin in vivo . The results showed that our test method can detect differences of 0.01 in friction coefficients.
Conclusion: TFA measurements allow the objective and reliable study of the tribology of the skin–textile biointerface and will be used to develop medical textiles with improved performance and greater efficacy for decubitus prevention.     

Adverse drug interactions and reactions in dermatology: current issues of clinical relevance

This article highlights several adverse drug interactions and reactions relevant to current dermatologic practice. Absorption interactions between drugs and compounds containing polyvalent cations, potential interactions between herbal and conventional medicines, the meaning of sulfa allergy, and adverse cutaneous reactions caused by epidermal growth factor receptor inhibitors are discussed.     

The decubitus ulcer: Facts and controversies

Defining the decubitus ulcer proves as difficult as agreeing on a name for the condition. Causes include pressure over bony prominences, shearing force, destruction of skin, and compromised blood flow. Evidence is emerging of the importance of ischemia as a primary causative agent, rather than pressure, which needs further investigation. Scales, staging, and treatment and prevention guidelines should be used with caution due to their arbitrary implementation and lack of evidence-based support. Unfortunately, much of the research and expert opinion developed by the government and touted as regulation lacks appropriate strength-of-evidence. Although decubitus ulcers should be prevented and treated to the best of our abilities, recognizing the possibility that the skin, like any other organ in the body, may fail is crucial.     

Surface adaptations of the vertebrate epidermis to friction.

Epidermal surfaces in representative vertebrates specialized for lowered or increased friction were studied with the scanning electron microscope. Microvillous and microridged patterns predominate in aquatic vertebrates. In squamate reptiles, the complex and varied ornamentation of the Oberh?utchen functions both in adhesive modifications and in modulating surface reflectivity. Frictional surfaces in birds and mammals are characterized more by anatomical than by cytologic specializations, the detailing of surface cells being mostly a function of turnover rate.     

Tissue stress and tumor promotion. Possible relevance to epidermolysis bullosa

Cutaneous carcinomas often arise in patients with severe epidermolysis bullosa (or other cutaneous ulcers) at multiple primary sites. Chronic tissue stress thus appears to promote carcinogenesis in preexisting somatic mutants in a stem cell population. Altered contractile properties of fibroblasts cultured from skin with epidermolysis bullosa may result from an altered interaction of these cells with their surrounding, chronically stressed, connective tissue matrix.     

Nanotechnology in medicine and relevance to dermatology: present concepts

Nanotechnology and nanomedicine are complementary disciplines aimed at the betterment of human life. Nanotechnology is an emerging branch of science for designing tools and devices of size 1-100 nm, with unique functions at the cellular, atomic and molecular levels. The concept of using nanotechnology in medical research and clinical practice is known as nanomedicine. Today, nanotechnology and nanoscience approaches to particle design and formulations are beginning to expand the market for many drugs and forming the basis for a highly profitable niche within the industry, but some predicted benefits are hyped. Under many conditions, dermal penetration of nanoparticles may be limited for consumer products such as sunscreens, although additional studies are needed on potential photooxidation products, experimental methods and the effect of skin condition on penetration. Today, zinc oxide and titanium dioxide nanoparticles (20-30 nm) are widely used in several topical skin care products such as sunscreens. Thus, in the present scenario, nanotechnology is spreading its wings to address the key problems in the field of medicine. The benefits of nanoparticles have been shown in several scientific fields, but very little is known about their potential to penetrate the skin. Hence, this review discusses in detail the applications of nanotechnology in medicine with more emphasis on the dermatologic aspects.     

Treatment of decubitus ulcer with Crilanomer and dextranomer

In a clinical study on decubital ulcers, 95 patients in 10 hospitals were treated with dextranomer and crilanomer. The size of the ulcer surface and the physician's evaluation of the healing status at the end of treatment served as the most important criteria for our assessment of the curative effect. Both preparations proved equivalent in the statistical test. Crilanomer revealed slightly better results than dextranomer with regard to the physician's overall evaluation al well as odor, exudation, and cleansing. Both modes of treatment were accompanied by local incompatibility reactions of a minor degree; there were no systemic side effects in either preparation.     

Pseudoangiosarcomatous squamous cell carcinoma of skin arising adjacent to decubitus ulcers

Pseudoangiosarcomatous, or pseudovascular, squamous cell carcinoma of skin is an unusual form of acantholytic (adenoid, pseudoglandular) squamous cell carcinoma that mimics the histolopathologic appearance of angiosarcoma. We report a case of pseudoangiosarcomatous squamous cell carcinoma arising adjacent to decubitus ulcers. The histopathologic examination of a wedge biopsy specimen revealed infiltrative cords of neoplastic cells that formed interanastomosing channels imitating angiosarcoma. Immunohistochemical staining was negative for the endothelial markers (CD31, CD34, and factor VIII-related antigen) and positive using cytokeratin antibodies (AE1/AE3 and 34 betaE12). Because of metastatic disease, palliative measures were undertaken and the patient died four months later. To our knowledge, our patient is the first with pseudoangiosarcomatous squamous cell carcinoma of skin developing within decubitus ulcer.     

Information excess in medicine. Overview, relevance to dermatology, and strategies for coping.

BACKGROUND--The amount of biomedical information contained in scientific journals has grown to the point that complete coverage of this material is impossible. The number of articles and journals being published has been growing at an exponential rate since 1750. Thirty-four thousand references from 4000 journals are added each month to the National Library of Medicine MEDLINE database from among the more than 100,000 scientific journals now published. This increase in scientific literature reflects not greater productivity but simply a larger number of scientists at work. Most articles written are eventually published in the medical literature, but a large number of scientific articles are of less than optimal quality, and most scientific articles that are published are never cited. Articles of higher quality and usefulness cluster in a few journals that enjoy great use in medical libraries and high scores on bibliometric scores such as the Science Citation Index. OBSERVATIONS--To assess the reading habits of dermatologic trainees and evaluate how they cope with this information excess, a survey was distributed to 36 residents in three training programs. The average number of medical journal reading hours per month was 17; the number of hours devoted to reading issues of the Archives of Dermatology, the Journal of the American Academy of Dermatology, and the Journal of Investigative Dermatology were 3.2, 5.0, and 1.4, respectively; and the average resident read seven peer-reviewed journals, two to four dermatologic tabloids, and four peer-reviewed medical journals. CONCLUSIONS--Critically and consistently reading a limited number of high-quality peer-reviewed journals as well as taking advantage of information available through computer networks and bibliographic and full-text databases is the best approach to coping with the volume of medical literature. Translating this information into a change in attitude and modification of physician behavior is best accomplished when local role models incorporate new ideas into their practice and teaching. Modifications that would, in fact, bring about truly useful changes, such as decreasing the number of new publications, melding journals already present into smaller numbers of publications rather than instituting new journals, altering the "publish-or-perish" rules, and writing more comprehensive articles rather than multiple small contributions, all await fundamental alterations in long-accepted policies in medicine.     

Peptidylarginine deiminases and deimination in biology and pathology: relevance to skin homeostasis

Deimination corresponds to the transformation of arginine residues within a peptide sequence into citrulline residues. Catalyzed by peptidylarginine deiminases, it decreases the net positive charge of proteins, alters intra and intermolecular ionic interactions and probably the folding of target proteins. Deimination has recently been implicated in several physiological and pathological processes. Here, we describe the enzymes involved in this post-translational modification, focusing on their expression, location and roles in skin, as well as their known protein substrates in the epidermis and hair follicles. We discuss also the potential involvement of deimination in human diseases including cutaneous disorders.     

Episodic angioedema with eosinophilia: precursor lesions and relevance of histology. A case report.

A 59-year-old patient suffered from persistent angioedema-like swellings and blood eosinophilia. The disease was preceded by an erythema multiforme-like exanthema and urticarial papules. Persistent eosinophilia with exclusion of its known causes and skin biopsy helped to establish the diagnosis of the benign variant of hypereosinophilic syndrome known as 'episodic angioedema with eosinophilia'. Corticosteroid therapy was successful. The therapeutic alternatives are discussed.