ABSTRACT
BACKGROUND: Animal models are important tools for studies in skin physiology and pathophysiology. Due to substantial differences in skin characteristics such as thickness and number of adnexa, the results of animal studies cannot always be directly transferred to the human situation. Therefore, transplantation of human skin on to SCID (severe combined immunodeficiency) mice might offer a promising tool to perform studies in viable human skin without the direct need for human volunteers. OBJECTIVES: To characterize the physiological and anatomical changes of a human skin transplant on a SCID animal host. METHODS: In this study human skin was transplanted on to 32 SCID mice and followed for 6 months. Barrier function was assessed by transepidermal water loss (TEWL; tewametry) and moisture content of the stratum corneum was studied by measurement of electrical capacitance (corneometry). RESULTS: The results showed considerable deviations of TEWL values and skin hydration between the grafts and human skin in vivo. The human skin showed epidermal hyperkeratosis and moderate sclerosis of the corium 4 and 6 months after transplantation on to SCID mice. CONCLUSIONS: Our results indicate that human skin does not completely preserve its physiological and morphological properties after transplantation on to SCID mice. Therefore, results from experiments using this model system need to be discussed cautiously.
Subject(s)
Disease Models, Animal , Skin Transplantation/pathology , Transplantation, Heterologous/pathology , Animals , Body Water/metabolism , Electric Capacitance , Epidermis/metabolism , Epidermis/physiology , Female , Humans , Mice , Mice, SCID , Skin Transplantation/physiology , Transplantation, Heterologous/physiology , Water Loss, InsensibleABSTRACT
Sunlight induces clinical, histological and physiological changes in the skin that are known as photoageing. As the population ages, prevention and treatment of photoageing is a growing challenge because of its association with skin cancer as well as for cosmetic reasons. Therefore, it is of interest to assess the degrees of photoageing by developing valid and comprehensive grading systems. Several different methods have been proposed. These include descriptive grading scales, visual analogue scales and photographic grading scales. The merits and inconveniences of these different approaches are discussed.
ABSTRACT
With respect to the clinical advantages known for bath PUVA therapy, it was of interest to compare the plasma levels of 8-methoxypsoralen (8-MOP) in bath therapy with those after oral administration for a better insight into the pharmacokinetics of 8-MOP following different modes of application. Considerable high plasma levels of 8-MOP were observed after bath therapy with interindividual variability. The half-life of plasma 8-MOP was markedly shorter after bath PUVA than after oral application. The pharmacokinetic profile of 8-MOP differs according to the mode of application.
Subject(s)
Baths , Methoxsalen/administration & dosage , Methoxsalen/blood , PUVA Therapy , Photosensitizing Agents/administration & dosage , Photosensitizing Agents/blood , Administration, Cutaneous , Administration, Oral , Adolescent , Adult , Aged , Aged, 80 and over , Area Under Curve , Biological Availability , Female , Half-Life , Humans , Male , Methoxsalen/pharmacokinetics , Middle Aged , Photosensitizing Agents/pharmacokinetics , Skin Absorption , Skin Diseases/drug therapy , Skin Diseases/metabolism , Time Factors , WaterABSTRACT
Chronic exposure to sunlight induces clinical, histological and physiological changes that are described as photoaging. To assess the resulting skin changes different clinical and photographic scores have been evaluated. Regarding different scoring systems a standardized grading system would be useful in a variety of indications, in particular to improve the quality of epidemiologic and clinical studies of photodamage. Photonumeric grading is considered superior to descriptive scales; however, the combination of both may suggest an advanced assessment of photodamage.
Subject(s)
Photography , Skin Aging/radiation effects , Sunlight/adverse effects , Humans , Reproducibility of Results , Skin Physiological PhenomenaABSTRACT
With aging, morphologic organ changes due to arteriosclerosis, hypertension, or diabetes increase, and renal transplantation tends to become less successful. We analyzed the outcome of transplantation in 123 recipients who underwent renal transplantation between January 1988 and December 1989. We assessed patient and graft survival after 1, 5, and 6 years as well as mortality and transplant failure and the incidence of rejections. We compared the results of patients aged under 60 years (group 1, n = 60) with the findings of patients aged over 60 years (group 2, n = 63). Immunosuppression was with cyclosporin A and prednisolone without exception. In patients under the age of 60, the overall patient survival at 1, 5, and 6 years was 97, 95, and 90% and was significantly compromised in recipients over the age of 60 (92, 80, and 75%). The 1-, 5- and 6-year graft survival rates were 92, 90, and 90% in recipients aged over 60 years and 88, 82, and 79% in recipients under the age of 60 years. The incidence of rejection was significantly higher in recipients under the age of 60. Patient mortality was mainly due to cardiovascular complications and transplant failure mainly related to transplant thrombosis. In older patients, renal transplantation is thought to be an option of survival rate improvement in comparison with hemodialysis. The incidence of transplant rejection is significantly lower, and this indicates a promising result regarding the long-term prognosis. As cardiovascular complications present as the main mortality factors of both transplant and patient, the prognosis is considered to be highly dependent on screening and treatment of these risk factors.
Subject(s)
Aging/physiology , Kidney Transplantation , Age Factors , Aged , Cardiovascular Diseases/epidemiology , Case-Control Studies , Female , Graft Rejection/epidemiology , Graft Survival , Humans , Immunosuppression Therapy , Incidence , Kidney Transplantation/mortality , Kidney Transplantation/physiology , Male , Middle Aged , Prognosis , Risk Factors , Survival RateABSTRACT
Irritant contact dermatitis has a broad spectrum of clinical features and is a leading cause of occupational disease worldwide. It has been shown previously that a combination of chemically different irritants may cause an additive effect compared to single application of these substances. In this study, tandem application of sodium lauryl sulfate and n-propanol was investigated in 20 human volunteers using non-invasive bioengineering methods, such as measurement of transepidermal water loss and chromametry. N-propanol did not enhance cumulative skin irritation when used with sodium lauryl sulfate, as has been reported for toluene. As n-propanol is the active ingredient in many disinfectants, this is of particular interest regarding occupational skin irritation in health care workers.