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At least 613 records · Page 34Linked to original sources
PubMed2001

Isolating a pure population of epidermal stem cells for use in tissue engineering.

Continuously renewing tissues, such as the epidermis, are maintained by stem cells that slowly proliferate and remain in the tissue for life. Although it has been known for decades that epithelial stem cells can be identified as label-retaining cells (LRCs) by long term retention of a nuclear label, isolating a pure population of stem cells has been problematic. Using a Hoechst and propidium iodide dye combination and specifically defined gating, we sorted mouse epidermal basal cells into three fractions, which we have now identified as stem, transient amplifying (TA), and non-proliferative basal cells. More than 90% of freshly isolated stem cells showed a G0/G1 cell cycle profile, while greater than 20% of the TA cells were actively dividing. Both stem and TA cells retained proliferative capacity, but the stem cells formed larger, more expandable colonies in culture. Both populations could be transduced with a retroviral vector and used to bioengineer an epidermis. However, only the epidermis from the stem cell population continued to grow and express the reporter gene for 6 months in organotypic culture. The epidermis from the transient amplifying cell fraction completely differentiated by 2 months. This novel sorting method yields pure viable epithelial stem cells that can be used to bioengineer a tissue and to test permanent recombinant gene expression.

Animals↗
PubMed2001

A comparative study of the effects on the skin of a classical bar soap and a syndet cleansing bar in normal use conditions and in the soap chamber test.

BACKGROUND/AIMS: The skin irritation potential of a body cleansing product is often compared under exaggerated test conditions, although the product is intended to be used at home with repetitive and brief contact with the skin. The aim of this study was to determine how much patch testing is predictive of the clinical, sub-clinical and subjective cutaneous effects of products used at home by consumers for their normal hygienic cleansing. METHODS: A double-blind comparative study of the normal use of an alkaline soap bar and a syndet at home during 10 consecutive weeks was performed on two identical groups of 25 healthy female subjects. The eventual skin changes observed at different anatomical skin sites were evaluated by clinical visual examination and by bioengineering measurements before the start of the study and then every 2 weeks. The objective measurements were compared with the subject's perceptions of dryness, tightness and product irritancy during the testing. RESULTS: The bioengineering measurements did not show any significant changes on all the anatomical skin sites, except for a small increase in skin pH with the classical soap bar. However, a trend appeared, showing that the alkaline soap bar is perceived by the subjects themselves as more of an irritant than the syndet bar. In the soap chamber test, the bar soap showed a significantly higher irritancy than the syndet bar. CONCLUSION: This study showed that cutaneous irritation induced by cleansing products in patch testing is not necessarily predictive of the irritation likely to occur in normal use conditions. Finally, a clear relationship could be demonstrated between the results of the soap chamber test and the consumer perception of both cleansing bars.

Adult↗
PubMed2002

Spinal cord stimulation facilitates functional walking in a chronic, incomplete spinal cord injured.

DESIGN: This paper describes a treatment paradigm to facilitate functional gait in a quadriplegic, ASIA C spinal cord injured (SCI), wheelchair-dependent subject who presented with some large fiber sensation, sub-functional motor strength in all lower limb muscles, and moderate spasticity. The study utilizes partial weight bearing therapy (PWBT) followed by epidural spinal cord stimulation (ESCS) with the assumption that both treatments would be necessary to elicit a well organized, near effortless functional gait with a walker. Function is defined in terms of accomplishing task-specific activities in the home and community. OBJECTIVES: To demonstrate the feasibility and benefits of combined PWBT and ESCS therapies aimed at promoting functional gait in a wheelchair-dependent ASIA C SCI subject. SETTING: The Clinical Neurobiology and Bioengineering Research Laboratories at Good Samaritan Regional Medical Center, Phoenix, Arizona, USA, and the Department of Bioengineering, Arizona State University, Tempe, Arizona, USA. METHODS: The study began with the application of PWBT. The subject walked on the treadmill until a plateau in gait rhythm generation was reached. Subsequently, ESCS, applied to the lumbar enlargement, was utilized to facilitate PWBT and, later, over-ground walking for a standard distance of 15 m. Gait performance was analyzed by measuring average speed, stepping symmetry, sense of effort, physical work capacity, and whole body metabolic activity. RESULTS: PWBT led to improved stereotypic stepping patterns associated with markedly reduced spasticity, but was insufficient for over-ground walking in terms of safety, energy cost, and fatigue. ESCS with PWBT generated immediate improvement in the subject's gait rhythm when appropriate stimulation parameters were used. When compared to the non-stimulated condition, over-ground walking with ESCS across a 15 m distance was featured by a reduction in time and energy cost of walking, sense of effort, and a feeling of 'lightness' in the legs. After a few months of training, performance in speed, endurance, and metabolic responses gradually converged with/without ESCS at this short distance, suggesting a learned response to these conditions. However, at longer distances (eg, 50-250 m), performance with ESCS was considerably superior. The subject was able to perform multiple functional tasks within the home and community with ESCS. CONCLUSION: We propose that ESCS augments the use-dependent plasticity created by PWBT and may be a valuable adjunct to post-SCI treadmill training in ASIA C subjects. We also conclude that ESCS elicits greater activation of an oxidative motor unit pool, thereby reducing the subject's sense of effort and energetic cost of walking.

Adult↗
PubMed2003

A new biological matrix for septal occlusion.

The ideal septal occluder scaffold should promote the healthiest and most complete healing response possible while eventually facilitating the full resorption of the material, leaving "native" tissue behind. An excellent biocompatibility of the scaffold tissue is a prerequisite for quick, complete, and firm ingrowth of the device, optimizing outcomes and minimizing the potential for complications. Intestinal collagen layer (ICL) is a highly purified (acellular) bioengineered type-1 collagen derived from porcine submucosa. It is gradually resorbed by the host organism and subsequently replaced by the host tissue. CardioSEAL occluders were modified by substituting the conventional polyester fabric for an intestinal collagen layer (ICL). Percutaneous transcatheter closure of interventionally created atrial septal defects was performed in lambs using these modified occluders. A complete pathomorphological investigation including histology was carried out after 2, 4, and 12 weeks follow-up. Standard CardioSEAL implants served as a control group. After 2 weeks in vivo the devices were already covered completely by neo-endothelium. Compared with the conventional synthetic scaffold, ICL devices showed a quicker endothelialization, decreased thrombogenicity, and superior biocompatibility with no significant cellular infiltration observed in the histology of explants with ICL fabrics. After 3 months in vivo the collagen layer remained mechanically intact, but began to show the first histological signs of mild disintegration, gradual resorption, and remodeling. In conclusion, short-term results from preliminary in vivo experiments using a bioengineered collagen matrix as the occluder tissue scaffold showed excellent biocompatibility. This resulted in superior overall results: quicker endothelialization, a decreased thrombogenicity, and decreased immunological host response.

Absorbable Implants↗
PubMedDate not supplied

Characteristics of self-estimated enhanced skin susceptibility.

A considerable number of people complain about enhanced skin sensitivity. The aim of this study was to investigate the characteristics of subjective statements and objective measurable parameters in subjects with self-estimated enhanced skin susceptibility. Four-hundred-and-twenty volunteers completed a questionnaire form with a self-estimation of skin susceptibility, possible triggering factors and other skin problems. In addition, basal values of transepidermal water loss, cutaneous blood flow and skin hydration were measured. One-hundred and fifty-two volunteers were also patch-tested with sodium lauryl sulphate 0.5% on the forearm and evaluated by bioengineering methods. We found no correlation between self-estimated skin susceptibility and bioengineering values, neither basal nor after sodium lauryl sulphate testing. These findings, along with interpretation of the questionnaire form, suggest that self-estimated enhanced skin susceptibility is a subjective problem mostly reported by women and of all ages.

Dermatitis, Irritant↗
PubMed2006

Sharpening the tools: a summary of a National Institutes of Health workshop on new technologies for detection of fetal cells in maternal blood for early prenatal diagnosis.

In 2003 the National Institute of Child Health and Human Development (NICHD) sponsored a workshop entitled "Sharpening the Tools", which was designed to explore the then current state of prenatal diagnosis and screening using fetal cells in maternal blood. The goals of the workshop were to: review the then current state of the field and assess present capabilities, identify future research needs and challenges in this area, identify promising new and innovative approaches for future exploration, and provide a written summary of the conference for public distribution. The workshop featured brief presentations by experts from a wide range of scientific fields and by innovative bioengineering and technology leaders from academic centers and private industry. The workshop was divided into presentations on target cells, target approaches for separation, genetic and protein analysis, and "out of the box" (bioengineering) approaches. The passage of time since the workshop has allowed an objective assessment of where the research has progressed. A 2006 update on the field is included at the end of the summary.

Blood↗
PubMed2001

Only early intervention with gamma-aminobutyric acid cell therapy is able to reverse neuropathic pain after partial nerve injury.

Pharmacological treatment for neuropathic pain, although often effective for brief periods, can result in intractable persistent pain with certain patients. Cell therapy for neuropathic pain is a newly developing technology useful for an examination of enhanced normal sensory function after nerve injury with the placement of cells near the spinal cord, and grafts of immortalized cells bioengineered to chronically supply the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) have been used to reverse the chronic pain behaviors. However, it is not known whether there is a therapeutic window for the use of intervention with cell therapy after partial nerve injury. To investigate whether neuropathic pain is sensitive to the timing of placement of cell grafts, neuronal cells bioengineered to synthesize GABA were transplanted in the lumbar subarachnoid space one to four weeks after unilateral chronic constriction injury (CCI) of the sciatic nerve and sensory behaviors were evaluated before and after CCI and transplants. Both thermal hyperalgesia and tactile allodynia were reversed when transplants were placed either one or two weeks after partial nerve injury, compared to maintenance of these behaviors with the injury alone. However, if GABA cells were placed any later than 2 weeks after nerve injury, such intervention was ineffective to reverse the thermal and tactile hypersensitivities induced by the injury. This suggests that altered spinal GABA levels may contribute to the early development of chronic neuropathic pain and that early intervention with cellular therapy to restore GABA may prevent the development of that pain.

Animals↗
PubMed2002

Formation of vascularized meniscal tissue by combining gene therapy with tissue engineering.

Ingrowth of host blood vessels into engineered tissues has potential benefits for successful transplantation of engineered tissues as well as healing of surrounding host tissues. In particular, the use of a vascularized bioengineered tissue could be beneficial for treating injuries to the meniscus, a structure in the knee where the lack of a vascular supply is associated with an inadequate healing response. In this study, gene transfer using an adenovirus vector encoding the hepatocyte growth factor gene (AdHGF) was used to induce blood vessel formation in tissue-engineered meniscus. Bovine meniscal cells were treated with AdHGF, a vector encoding a marker gene E. coli beta-galactosidase (Adbetagal), or no virus. Cells were seeded onto poly-glycolic acid felt scaffolds and then transplanted into the subcutaneous pouch of athymic nude mice for 8 weeks. Expression of the marker gene and HGF was detectable for several weeks after gene transfer. Ink injection studies showed that AdHGF-treated meniscal cells formed tissue which contained fourfold more blood vessels at 2 weeks (p < 0.02) and 2.5-fold more blood vessels at 8 weeks (p < 0.001) posttransplantation than controls. This study demonstrates the feasibility of using adenovirus-mediated gene transfer to engineer a blood supply in the bioengineered meniscal tissue.

Adenoviridae↗
PubMed2006

To make a new intestinal mucosa.

A number of clinical conditions are caused by disorders affecting the mucosal lining of the gastrointestinal tract. Some patients suffer from a loss of mucosal surface area due to congenital defects or due to surgical resections ("short bowel syndrome"). Other patients have inborn or acquired defects of certain mucosal functions (e.g., glucose-galactose malabsorption, bile acid malabsorption). Many patients with these mucosal disorders could be more effectively treated if healthy mucosa were available in larger quantities as a replacement or functional supplement. We therefore developed methods to transplant mucosal stem cells from one part of the intestine to another and to make bioengineered intestinal mucosa. We generated an animal model of bile acid malabsorption using rats that underwent resection of the distal 25% of their small intestine (ileum). This resulted in significant losses of bile acids with the fecal excretions in these animals. We subsequently harvested ileal stem cell clusters from neonatal donors, removed the mucosa from a segment of proximal intestine (jejunum), and implanted the stem cell clusters into the debrided segment of jejunum. After four weeks, the animals had developed a functional "neomucosa." We inserted the "neo-ileal" segment into continuity as a substitute ileum. Postoperative measurements of fecal bile acid excretion showed that we were able to reverse the malabsorption syndrome in this model. This was the first reported neo-mucosa-based treatment of a malabsorption syndrome in vivo. We subsequently studied different biodegradable PGA and PLLA scaffoldings to generate bioengineered intestinal mucosa. We implanted these materials into omentum of rats and were able to identify a PGA/PLLA hybrid material on which engraftment rates of 36% of the available surface area could be achieved. Most recently, we developed a novel technique that permits direct observation of cell-biomaterial interactions after implantation into omentum or intestine in vivo. This method will help to optimize engraftment conditions for stem cell clusters on biomaterials.

Animals↗
PubMedDate not supplied

Tissue-engineered hybrid tooth and bone.

Tooth loss accompanied by alveolar bone resorption presents a significant clinical problem. We have investigated the utility of a tissue-engineering approach to provide corrective therapies for tooth-bone loss. Hybrid tooth-bone tissues were bioengineered as follows. Tooth implants were generated from pig third molar tooth bud cells seeded onto polyglycolide (PGA) and polyglycolide-colactide (PLGA) scaffolds, and grown for 4 weeks in the omenta of adult rat hosts. Bone implants were generated from osteoblasts induced from bone marrow progenitor cells obtained from the same pig, seeded onto PLGA fused wafer scaffolds, and grown for 10 days in a rotational oxygen-permeable bioreactor system. The tooth and bone implants were harvested, sutured together, reimplanted, and grown in the omenta for an additional 8 weeks. Histological and immunohistochemical analyses of the excised hybrid tooth-bone constructs revealed the presence of tooth tissues, including primary and reparative dentin and enamel in the tooth portion of hybrid tooth-bone implants, and osteocalcin and bone sialoprotein-positive bone in the bone portion of hybrid tooth-bone constructs. Collagen type III-positive connective tissue resembling periodontal ligament and tooth root structures were present at the interface of bioengineered tooth and bone tissues. These results demonstrate the utility of a hybrid tooth-bone tissue-engineering approach for the eventual clinical treatment of tooth loss accompanied by alveolar bone resorption.

Animals↗
PubMed2006

Embryonic myocardium shows increased longevity as a functional tissue when cultured in the presence of a noncardiac tissue layer.

A major aim of regenerative medicine is the construction of bioengineered organs and tissue for transplantation into human patients; yet living tissue is dynamic, and thus arranging cellular and extracellular constituents into an architecture resembling normal adult organs may not be sufficient to maintain tissue stability. In this study, we used cultures of embryonic chick heart tissue as a model to explore how newly formed cardiac tissue constructs can sustain their morphological structure and functional capabilities over extended periods. During the initial days of incubation, embryonic cardiac explants will thrive as beating three-dimensional tissue aggregates. However, within the first week of culture, cardiac aggregates lose their contractile function and flatten. After 2 weeks of incubation, the cardiac cells will have spread out into a homogeneous monolayer and dedifferentiated to a noncardiac phenotype. In contrast, when the embryonic heart tissue was co-cultured with a noncardiac cell layer obtained from adult bone marrow, the cardiac aggregates maintained their contractile function, three-dimensional tissue morphology, and myocyte phenotype for a full month of incubation. The capacity of this noncardiac cell layer to sustain the phenotype and morphology of the cardiac explants was partially replicated by treatment of the heart tissue with conditioned media from bone marrow cells. These findings are discussed in regard to the importance of adjacent cell layers for facilitating organogenesis in the developing embryo and having potential utility in producing stable bioengineered tissue constructs.

Animals↗
PubMed2005

Characterization of the initial response of engineered human skin to sulfur mustard.

We have used a new approach to identify early events in sulfur mustard-induced, cutaneous injury by exposing human, bioengineered tissues that mimic human skin to this agent to determine the morphologic, apoptotic, inflammatory, ultrastructural, and basement membrane alterations that lead to dermal-epidermal separation. We found distinct prevesication and post-vesication phases of tissue damage that were identified 6 and 24 h after sulfur mustard (SM) exposure, respectively. Prevesication (6 h) injury was restricted to small groups of basal keratinocytes that underwent apoptotic cell death independent of SM dose. Immunoreactivity for basement membrane proteins was preserved and basement membrane ultrastructure was intact 6 h after exposure. Dermal-epidermal separation was seen by the presence of microvesicles 24 h after SM exposure. This change was accompanied by the dose-dependent induction of apoptosis, focal loss of basement membrane immunoreactivity, increase in acute inflammatory cell infiltration, and ultrastructural evidence of altered basement membrane integrity. These studies provide important proof of concept that bioengineered, human skin demonstrates many alterations previously found in animal models of cutaneous SM injury. These findings further our understanding of mechanisms of SM-induced damage and can help development of new countermeasures designed to limit the morbidity and mortality caused by this chemical agent.

Animals↗
PubMedDate not supplied

Does leaf water efficiency vary among eucalypts in water-limited environments?

There is a need to generalize water use behavior of eucalypts to facilitate bioengineering and landscape remediation programs in a wide range of Australian environments. A critical question can be stated as a null hypothesis: tree water use per unit leaf area (leaf efficiency) is independent of eucalypt species. This is implicitly equivalent to the hydrological equilibrium hypothesis that states that leaf area is a function of climate, at least in cases where transpiration and growth are limited by soil water. Failure to reject this null hypothesis simplifies (a) the selection of tree species for water balance management, (b) the generation of regional-scale expectations of leaf area index, and (c) the estimation (monitoring) of the effectiveness of plantations in controlling site water balance. The hypothesis was tested with tree water use data collected in natural multi-species stands across Australia, including sites in the wet-dry season tropical woodlands of the Northern Territory, the Mediterranean climate forests of Western Australia, and a woodland system in southern New South Wales receiving an even distribution of rainfall throughout the year. We also tested the hypothesis in a multi-species tree plantation growing on a saline gradient. In each case, we could not reject the hypothesis of constant leaf efficiency among eucalypts. In every case there was a common, strong, linear relationship among tree leaf area and mean daily water use by all tree species in a sample. Single factor (species) analysis of variance did not detect significant differences between leaf water efficiencies of species. For the jarrah forest (Eucalyptus marginata J. Donn ex Sm., E. calophylla R. Br. ex Lindl.), the null hypothesis held in both spring (wet) and autumn (dry) conditions. The null hypothesis held in the mixed species woodland of New South Wales (E. macrorhynca F.J. Muell. ex Benth., E. blakelyi Maiden., E. polyanthemos Schauer.) under summer and autumn conditions, and across five species in the wet-dry tropical woodland (E. miniata A. Cunn. ex Schauer, E. tetrodonta F.J. Muell., E. porecta S.T. Blake, Erythrophleum chlorostachys F.J. Muell., and Terminalia ferdinandiana Exell.). The null hypothesis also held for a plantation of E. occidentalis Endl. and provenances of E. camaldulensis Dehnh. growing on a shallow saline gradient; i.e., leaf water efficiency remained constant across species and varieties despite obvious effects of salinity on the size of individual canopies. We conclude that there is little evidence for rejecting the hypothesis that leaf efficiency does not vary significantly among sympatric eucalypt species in rainfall-limited (soil-water-limited) systems. These findings open the way for useful bioengineering generalities about the hydrological role of trees in the Australian landscape.

Journal Article↗
PubMed2006

Long- and short-chain plant-produced bacterial N-acyl-homoserine lactones become components of phyllosphere, rhizosphere, and soil.

Two N-acyl-homoserine lactone (acyl-HSL) synthase genes, lasI from Pseudomonas aeruginosa and yenI from Yersinia enterocolitica, were introduced into tobacco, individually and in combination. Liquid chromatograph-tandem mass spectrometry and thin-layer chromatography confirmed products of lasI and yenI activity in single and cotransformants. Cotransformants expressing plastid-localized LasI and YenI synthases produced the major acyl-HSLs for each synthase in all tissues tested. Total acyl-HSL signals accumulated in leaf tissue up to 3 pmol/mg of fresh weight, half as much in stem tissue, and approximately 10-fold less in root tissues. Acyl-HSLs were present in aqueous leaf washes from greenhouse-grown transgenic plants. Transgenic lines grown for 14 days under axenic conditions produced detectable levels of acyl-HSLs in root exudates. Ethyl acetate extractions of rhizosphere and nonrhizosphere soil from transgenically grown plants contained active acyl-HSLs, whereas plant-free soil or rhizosphere and nonrhizosphere soil from wild-type plants lacked detectable amounts of acyl-HSLs. This work shows that bioactive acyl-HSLs are exuded from leaves and roots and accumulate in the phytosphere of plants engineered to produce acyl-HSLs. These data further suggest that plants that are bioengineered to synthesize acyl-HSLs can foster beneficial plant-bacteria communications or deter deleterious interactions. Therefore, it is feasible to use bioengineered plants to supplement soils with specific acyl-HSLs to modulate bacterial phenotypes and plant-associated bacterial community structures.

4-Butyrolactone↗
PubMed2000

Wall Street's assessment of plastic surgery--related technology: a clinical and financial analysis.

Many plastic surgeons develop technologies that are manufactured by Wall Street-financed companies. Others participate in the stock market as investors. This study examines the bioengineered skin industry to determine whether it integrates clinical and financial information as Wall Street tenets would predict, and to see whether the financial performance of these companies provides any lessons for practicing plastic surgeons. In efficient markets, the assumptions on which independent financial analysts base their company sales and earnings projections are clinically reasonable, the volatility of a company's stock price does not irrationally differ from that of its industry sector, and the buy/sell recommendations of analysts are roughly congruent. For the companies in this study, these key financial parameters were compared with a benchmark index of 69 biotech companies of similar age and annual revenues (Student's t test). Five bioengineered skin companies were included in the study. Analysts estimated that each company would sell its product to between 24 and 45 percent of its target clinical population. The average stock price volatility was significantly higher for study companies than for those in the benchmark index (p < 0.05). Similarly, buy/sell recommendations of analysts for the study companies were significantly less congruent than those for the benchmark companies (p < 0.05). These results indicate clinically unrealistic projections for market penetration, significantly high price volatility, and significantly high discordance among professional analysts. In all cases, the market is inefficient-an unusual finding on Wall Street. A likely explanation for this market failure is a cycle of poor clinical correlation when assigning sales projections, which in turn leads to price volatility and discordance of buy/sell recommendations. This study's findings have implications for plastic surgeons who develop new technology or who participate in the equities markets as investors. Plastic surgeons who develop new medical devices or technology cannot universally depend on the market to drive clinically reasonable financial performance. Although inflated sales estimates have benefits in the short term, failure to meet projections exacts severe financial penalties. Plastic surgeons who invest in the stock market, because of their unique clinical experience, may sometimes be in the position to evaluate new technologies and companies better than Wall Street experts. Well-timed trades that use this expertise can result in opportunities for profit.

Biomedical Engineering↗
PubMed2003

Assessment of irritant skin reactions using electrical impedance--a comparison between 2 laboratories.

To assess interlaboratory variability in the measurement of skin electrical impedance (IMP), we evaluated irritant reactions to sodium lauryl sulfate (SLS) (2%) and nonanoic acid (NAA) (40%) in 2 laboratories. We studied the patch test responses in 40 healthy male and female volunteers between 20 and 30 years of age (20 in each laboratory) with an instrument for measuring IMP. 2 other bioengineering methods and visual scoring were also used to facilitate further illumination of any findings. A strict protocol including all details of the measurement procedure was carefully implemented in both laboratories. The skin reactions were evaluated at 23 h and at 3, 7 and 14 days after exposure. Our findings show that both irritants caused distinct dynamic responses detectable with the bioengineering techniques. Interestingly, the IMP baseline values varied between the 2 laboratories. Moreover, at early stages in the development of irritation (day 1), the irritants induced changes in IMP indices in the opposite direction, which accords with the concept of various IMP patterns of contact dermatitis caused by different irritants. Although the absolute values of IMP differed in both laboratories, the dynamic response patterns were the same.

Adult↗
PubMed2005

Transepidermal water loss and incidence of hand dermatitis in a prospectively followed cohort of apprentice nurses.

The purpose of the study was to evaluate the incidence of hand dermatitis, the impact of potential risk factors and the efficacy of skin bioengineering in a prospectively followed cohort of apprentice nurses. 104 participants were prospectively followed for 3 years. Before the start of training, after about 1 year and in the third year of occupational exposure, a standardized questionnaire was distributed, and a clinical examination with skin bioengineering of the dorsum of hand and forearm was performed. The 12-month period prevalence of self-reported symptoms of hand dermatitis was 36.5%[95%-confidence interval (CI) 27.3-46.6] at intermediate follow-up and 43.3% (95%-CI 33.6-53.3) at the final examination. Apprentices with self-reported symptoms at the final examination showed a significant increase of transepidermal water loss (TEWL) at the dorsal hand from 10.15 g/m2h to 13.55 g/m2h. TEWL at this site did, at the initial examination, not differ significantly between persons who later reported symptoms of hand dermatitis at the final examination and those who did not (10.50 g/m2h versus 10.15 g/m2h, respectively). Our results do not support the notion that an increased basal TEWL is a good indicator for hand dermatitis risk.

Adult↗
PubMed1989

Quantification of the DMSO-response--a test for assessment of sensitive skin.

The DMSO-test has been suggested as a means of assessing skin sensitivity. When DMSO is applied to the skin a whealing response is provoked, and the magnitude of the response depends on the susceptibility of the individual. In this study clinical grading, along with transepidermal water loss measurement (TEWL), electrical conductance, laser Doppler flowmetry and ultrasound skin thickness measurement have been used for quantification of the DMSO-response. It is concluded that TEWL measurement, electrical conductance and ultrasound skin thickness measurement are all suitable methods for quantifying the DMSO-response, while laser Doppler flowmetry, due to interference from oedema formation, should not be used for this purpose. The ultrasound technique was quick and simple to handle as compared to the other bioengineering methods. The DMSO-test is an interesting and realistic possibility as a test for skin sensitivity and, with new bioengineering methods, the separate phenomena comprising the response can be evaluated and quantified, improving the objectivity of the test.

Adult↗