Search

Previous studies have indicated that volatile organic compounds specific to bladder cancer may exist in urine headspace, raising the possibility that they may be of diagnostic value for this particular cancer. To further examine this hypothesis, urine samples were collected from patients diagnosed with either bladder cancer or a non‐cancerous urological disease/infection, and from healthy volunteers, from which the volatile metabolomes were analysed using gas chromatography mass spectrometry. The acquired data were subjected to a specifically designed pattern recognition algorithm, involving cross‐model validation. The best diagnostic performance, achieved with independent test data provided by healthy volunteers and bladder cancer patients, was 89% overall accuracy (90% sensitivity and 88% specificity). Permutation tests showed that these were statistically significant, providing further evidence of the potential for volatile biomarkers to form the basis of a non‐invasive diagnostic technique.

In a previous canine study, we demonstrated that volatile organic compounds specific to bladder cancer are present in urine headspace, subsequently showing that up to 70% of tumours can be correctly classified using an electronic nose. This study aimed to evaluate the sensitivity and specificity which can be achieved by a group of four trained dogs. In a series of 30 double-blind test runs, each consisting of one bladder cancer urine sample placed alongside six controls, the highest sensitivity achieved by the best performing dog was 73% (95% CI 55-86%), with the group as a whole correctly identifying the cancer samples 64% (95% CI 55-73%) of the time. Specificity of the dogs individually ranged from 92% (95% CI 82-97%) for urine samples obtained from healthy, young volunteers down to 56% (95% CI 42-68%) for those taken from older patients with non-cancerous urological disease. Odds ratio comparisons confirmed a significant decrease in performance as the extent of urine dipstick abnormality and/or pathology amongst the control population increased. Importantly, however, statistical analysis indicated that covariates such as smoking, gender and age, as well as blood, protein and /or leucocytes in the urine did not significantly alter the odds of response to the cancer samples. Our results provide further evidence that volatile biomarkers for bladder cancer exist in urine headspace, and that these have the potential to be exploited for diagnosis.

Patch testing with chemical irritants almost always produces a striking variability in the intensity of reaction between individuals, even amongst normal, healthy subjects. Whilst there have been many attempts to define factors which predispose to heightened or, conversely, to diminished reactivity, the underlying cellular mechanisms responsible for the variability remain poorly understood. In this review, a number of possible explanations are proposed, with a particular emphasis on those which relate to the influence of pre-existing disease or to the genetic regulation of certain immunological and inflammatory processes.

The aims of this study were to utilize quantitative immunocytochemical techniques to determine the densities of keratin 16 (K16) and keratin 17 (K17) expressed by keratinocytes during the course of acute patch test reactions to sodium lauryl sulfate (SLS), and to relate these to the proliferative state of the epidermis, as assessed by Ki-67 immunolabelling. Significantly increased numbers of dividing keratinocytes were present in 48h and 96h reactions, concurrent with high levels of expression of K16 and more moderate expression of K17. Statistical analysis indicated a good correlation between K16 expression and the density of Ki-67+ keratinocytes present in the epidermis (r=0.843). This was not the case for K17 (r=0.396). The results demonstrate that both K16 and K17 expression are features of acute irritant contact dermatitis reactions, but suggest that the factors which influence and control their expression differ.

In previous studies, we showed that a number of aspects of the histopathology of irritant contact dermatitis arc profoundly influenced by the chemical nature of the irritant applied. We report here that this phenomenon also extends to the infiltration of leukocytes into the epidermis. Healthy volunteers were patch tested with the following irritants and their appropriate controls: benzalkonium chloride, sodium lauryl sulphate, crown oil, dithranol, nonanoic acid, and propylene glycol. After visually grading the intensity of the resulting inflammation, biopsies were removed and the major phenotypic classes of leukocytes identified immunocytochemically. Dermal and epidermal cell densities were determined, and the expression of several activation/proliferation antigens studied. We found a similar pattern of cellular infiltration in the dermis of all irritant groups; the densities of most of the cell types rising in line with the intensity of inflammation. Within the epidermis, however, there were marked differences in the patterns of cellular infiltration between the irritant groups, leading to poorer correlations between leukocyte density and visual grading. The greatest disparity occurred between croton oil and nonanoic acid biopsies, the former being characterized by the influx of large numbers of leukocytes, the latter showing remarkably little exocytosis. Infiltration of neutrophils occurred to varying degrees with all irritants, but a disproportionately large number were present in sodium lauryl sulphate biopsies. All control groups showed a rise in CD4 + cells, with distilled water also producing increases in CD11c+ cells and neutrophils. A selective influx of CD25 + cells occurred in the epidermis of both irritant and control groups. Our observations further highlight the heterogeneous nature of irritant contact dermatitis, and confirm previous findings that visually negative control patch tests show marked cellular reactivity.

Previous studies have indicated that volatile compounds specific to bladder cancer may exist in urine headspace, raising the possibility that headspace analysis could be used for diagnosis of this particular cancer. In this paper, we evaluate the use of a commercially available gas sensor array coupled with a specifically designed pattern recognition algorithm for this purpose. The best diagnostic performance that we were able to obtain with independent test data provided by healthy volunteers and bladder cancer patients was 70% overall accuracy (70% sensitivity and 70% specificity). When the data of patients suffering from other non-cancerous urological diseases were added to those of the healthy controls, the classification accuracy fell to 65% with 60% sensitivity and 67% specificity. While this is not sufficient for a diagnostic test, it is significantly better than random chance, leading us to conclude that there is useful information in the urine headspace but that a more informative analytical technique, such as mass spectrometry, is required if this is to be exploited fully.

The expression of three immunoregulatory surface antigens by epidermal keratinocytes was studied in irritant contact dermatitis (ICD), in order to assess whether keratinocytes have a modulatory role in the pathogenesis of this disorder. Biopsies were taken from 48-h patch test reactions to six structurally unrelated irritants, and frozen sections immunolabeled with monoclonal antibodies to the major histocompatibility complex class II antigen, HLA-DR, intercellular adhesion molecule-1 (ICAM-1), and the 88-Kd glycoprotein CD36 (OKM5), as well as to the CD3 (T cells) and CD11a (lymphocyte function associated antigen-1, LFA-1) antigens. We found that there was very limited expression of HLA-DR by keratinocytes, with no correlation between the extent of HLA-DR positivity and the degree of T cell infiltration into the epidermis and dermis, suggesting that interferon gamma may not be a significant mediator of ICD at 48 h. In contrast, keratinocytes showed extensive upregulation of ICAM-1, with an excellent spatial association between ICAM-1 expression and LFA-1 positive leucocytes in the epidermis. This indicates that keratinocyte ICAM-1 induction is not restricted to diseases in which antigen presentation is pivotal, but that it has a generalized role in cutaneous inflammatory reactions, promoting the infiltration of leucocytes into the epidermis. Immunolabeling with OKM5 revealed that CD36 is present to a variable degree on keratinocytes in normal skin. Differential changes in the pattern of keratinocyte expression occurred between irritants, in a manner that suggested that the CD36 antigen does not act as an adhesion molecule in ICD, but rather that its expression is related to the proliferative state of the epidermis. The results of this study demonstrate that immune-associated antigens are selectively expressed on the surface of keratinocytes in 48-h ICD biopsies, implying that these cells play an important regulatory role in the development of the inflammatory response to irritant chemicals.

In order to gain a greater insight into the complex mechanisms of action of different irritant chemicals on the skin, we have studied the behavior of epidermal CD1+ cells in experimentally induced irritant contact dermatitis. Healthy, human volunteers were patch tested for 48 h with the following six chemically unrelated irritants and their appropriate vehicle controls; benzalkonium chloride, sodium lauryl sulphate, dithranol, nonanoic acid, croton oil, and propylene glycol. After visually assessing and grading the resulting inflammatory reactions, punch biopsies were taken and the morphology and density of CD1+ cells in the epidermis studied using immunocytochemical techniques in combination with image analysis and electron microscopy. Statistically significant decreases in the epidermal density of CD1+ cells occurred in the responses to dithranol (p less than 0.05) and nonanoic acid (p less than 0.01). Importantly, these changes in density were not simply due to variations in the intensity of inflammatory response (r = 0.1157). Alterations in the length of the dendritic processes of CD1+ cells were also induced, and semi-quantitative analysis revealed significant decreases in dendrite length in the reactions to sodium lauryl sulphate (p less than 0.05), nonanoic acid (p less than 0.001), croton oil (p less than 0.05), and dithranol (p less than 0.005). Unlike epidermal density, however, this effect on cell morphology was directly related to the severity of inflammation (r = -0.74, p less than 0.01). Morphologic evidence of cellular injury to Langerhans cells was seen by electron microscopy in the majority of biopsies, although relatively few cells were affected in sodium lauryl sulphate and propylene glycol reactions. Benzalkonium chloride, unlike the other irritants, also induced a state of metabolic activation in a high proportion of epidermal Langerhans cells. Lymphocyte/Langerhans cell apposition was observed in most samples, but was particularly prevalent in the reactions to dithranol. The results of this study demonstrate that significant changes in the morphology and density of Langerhans cells occur in irritant contact dermatitis, some of which are directly influenced by the chemical nature of the irritant.

Objective To determine whether dogs can be trained to identify people with bladder cancer on the basis of urine odour more successfully than would be expected by chance alone. Design Experimental, “proof of principle” study in which six dogs were trained to discriminate between urine from patients with bladder cancer and urine from diseased and healthy controls and then evaluated in tests requiring the selection of one bladder cancer urine sample from six controls. Participants 36 male and female patients (age range 48-90 years) presenting with new or recurrent transitional cell carcinoma of the bladder (27 samples used for training; 9 used for formal testing); 108 male and female controls (diseased and healthy, age range 18-85 years—54 samples used in training; 54 used for testing). Main outcome measure Mean proportion of successes per dog achieved during evaluation, compared with an expected value of 1 in 7 (14%). Results Taken as a group, the dogs correctly selected urine from patients with bladder cancer on 22 out of 54 occasions. This gave a mean success rate of 41% (95% confidence intervals 23% to 58% under assumptions of normality, 26% to 52% using bootstrap methods), compared with 14% expected by chance alone. Multivariate analysis suggested that the dogs’ capacity to recognise a characteristic bladder cancer odour was independent of other chemical aspects of the urine detectable by urinalysis. Conclusions Dogs can be trained to distinguish patients with bladder cancer on the basis of urine odour more successfully than would be expected by chance alone. This suggests that tumour related volatile compounds are present in urine, imparting a characteristic odour signature distinct from those associated with secondary effects of the tumour, such as bleeding, inflammation, and infection.

Udgivelsesdato: 2004-May A multicentre, randomized, double-blind, crossover study was designed to investigate the effects of prednisone on allergic and irritant patch test reactions. 24 subjects with known allergy to nickel were recruited and patch tested with a nickel sulfate dilution series in aqueous solution, 5% nickel sulfate in petrolatum and 2 dilution series of the irritants nonanoic acid and sodium lauryl sulfate. The subjects were tested x2, both during treatment with prednisone 20 mg oral daily and during placebo treatment. The total number of positive nickel patch test reactions decreased significantly in patients during prednisone treatment. The threshold concentration to elicit a patch test reaction increased and the overall degree of reactivity to nickel sulfate shifted towards weaker reactions. The effect of prednisone treatment on the response to irritants was divergent with both increased and decreased numbers of reactions, although there were no statistically significant differences compared with placebo. It is concluded that oral treatment with prednisone suppresses patch test reactivity to nickel, but not to the irritants tested.

The ultrastructural changes seen in acute contact dermatitis vary according to the chemical nature and concentration of the substance applied to the skin, the intensity of the response and the time of biopsy. In general, irritants have a greater impact on the stratum corneum than allergens, and produce a wider variety of morphological changes in the viable layers of the epidermis, a reflection of the heterogeneity in their mechanisms of action. Allergic contact dermatitis reactions are generally more uniform, the predominant ultrastructural changes being spongiosis, vesiculation and exocytosis. Epidermal Langerhans cells within both allergic and irritant patch test reactions show ultrastructural evidence of activation and degeneration, and are frequently seen in apposition to lymphocytes. Oedema and capillary dilation are the most commonly described features within the dermis of allergic and irritant patch test reactions. Our knowledge of the ultrastructure of chronic contact dermatitis remains limited.

Patch testing is an invaluable tool for the experimental induction of acute irritant contact dermatitis (ICD), with a variety of chamber systems available for use. Ideally, the inflammatory reactions produced should be of uniform intensity across the test area, thereby facilitating grading of the response and tissue sampling for histopathological studies. Unfortunately, annular, follicular and/or blotchy erythema frequently occur. In this study, we set out to compare the performance of 5 patch test systems (8 mm, 12 mm and 18 mm Finn Chambers; 19 mm and 25 mm Hilltop chambers) when testing normal healthy volunteers with sodium lauryl sulfate at concentrations selected to produce mild, moderate and moderately severe reactions. Visual assessment of the patch test sites revealed good dose responses with all 5 chamber types. Uniformity of erythema across the test site was more closely linked to the actual intensity of response than the delivery system itself, mild reactions being far less likely to display homogeneous erythema than moderately severe reactions. Extra large chambers did not perform significantly better than smaller chambers. Balancing the need for a uniform reaction pattern and adequate tissue sampling area, against the exposure risk, we conclude that 12 mm Finn Chambers represent the optimum patch test system for acute SLS-induced irritation where histopathological investigations are the ultimate aim.

Chronic hand dermatitis is a common and distressing condition with a complex, multifactorial aetiology. In order to better understand its pathophysiology and hopefully improve diagnosis, we have begun a systematic histopathological study of various forms of hand dermatitis, with a particular emphasis on those in which exposure to irritants and allergens is strongly implicated. Suitable patients were recruited from amongst those presenting at the contact dermatitis clinic. Detailed past and present medical and personal histories, clinical examination, patch testing and prick testing were conducted in order to classify the eczema into one of several broad entities e.g. chronic irritant contact dermatitis (CICD), with or without atopy. After performing a range of bio-engineering measurements on a pre-selected affected area of the hand, biopsies were removed and processed for high resolution light microscopy and immunocytochemistry. Age/sex matched, healthy, non-atopic individuals provided control skin from similar sites of the hand. Using a range of antibodies and quantification techniques, we examined the status and expression of certain immune-associated cells and receptor/adhesion molecules. Of note amongst these, were the differences in epidermal CD1a+ cell density between groups. Non-atopics with CICD, for example, had significantly fewer CD1a+ cells than both atopics with CICD and those with normal skin. CD54 (ICAM-1) and several cytokine/chemokine receptors were more widely and strongly expressed by keratinocytes in those with an atopic diathesis. Although preliminary in nature at this stage, our results suggest that different forms of hand dermatitis display characteristic immunopathological features which may possibly be of diagnostic value.

Alterations in the proliferative capacity of human epidermis following topical exposure to structurally unrelated chemical irritants were investigated, with the aim of improving our understanding of the cellular changes that take place during the development of irritant contact dermatitis (ICD). Healthy volunteers were patch tested for 48h with the following six irritants and their appropriated vehicle and occlusion controls: 5% sodium lauryl sulphate (SLS), 0.5% benzalkonium chloride, 80% nonanoic acid (NAA), 0.02% dithranol, 0.8% croton oil, and 100% propylene glycol (PG). After the degree of inflammation induced was visually graded, biopsy samples were removed and the dividing keratinocytes were identified immunocytochemically by using the monoclonal antibody Ki-67, with quantification being performed on the basis of the number of positive cells/100 basal keratinocytes. statistically significant increases in the density of proliferating cells occurred in the density of proliferating cells occurred in the reaction to SLS, NAA, and PG, whereas, in contrast, dithranol caused a marked decrease in the number of dividing keratinocytes. Overall, the density of proliferating keratinocytes did not show a linear relationship with the visually assessed intensity of inflammation, indicating that the changes observed were related to the chemical nature of the individual irritants and their specific biochemical interactions with the keratinocytes, rather than being the consequence of a generalized inflammatory response. Differential release of epidermal cytokines and mediators by the six irritants may account for these varying states of keratinocyte proliferation. Application of the Spearman rank coefficient of correlation revealed that the changes in mitotic activity of keratinocytes were unrelated either to the total density of leukocytes infiltrating the epidermis and dermis, or to the individual densities of the major phenotypic classes of inflammatory cells present. This makes it unlikely that the localized release of cytokines by infiltrating leukocytes is, by itself, the primary factor in the alteration in epidermal cell kinetics seeen in ICD. Our results provide a further demonstration of the diverse actions of different chemical irritants on human skin and emphasize the need to regard ICD as a heterogeneous disorder.

EDITOR—We were well aware of the need to consider lifestyle and environmental factors associated with bladder cancer. As stated in our methods section, we collected comprehensive data on each participant, including occupation, dietary intake, hobbies, drug treatment, and, most importantly, smoking habits. We specifically designed the training regimen to take into account the association between smoking, bladder cancer, and the possible presence of tobacco related odours in …

Assessment of erythema in experimentally-induced irritant contact dermatitis has been performed visually and using the laser Doppler flowmeter (LDF). A close correlation was shown between the 2 methods (r = 0.9079, p less than 0.001), with the LDF producing mean blood flow values which were able to discriminate between the different visual scores. Of the 100 patch tests evaluated, 3 gave poor correlations between their visual and LDF readings, including 2 dithranol reactions and 1 sodium hydroxide response. Patch tests with no visible erythema had blood flow values similar to those of normal untreated skin. Although the LDF was an easy instrument to operate, it was not considered suitable for use in the routine patch test clinic, due mainly to the unacceptable length of time required to measure each patch test.

SUMMARY The histopathological features of allergic contact dermatitis were compared with those of irritant contact dermatitis in a group of 17 subjects. Each patient received simultaneous patch tests of a known allergen and a standardized irritant (benzalkonium chloride). The cellular changes occurring between 3 h and 7 days after patch test application were studied by light and electron microscopy and immunocytochemistry. No differences were observed between the induced allergic contact dermatitis (ACD) and the irritant contact dermatitis (ICD), either in the responding cell types or the sequence of cellular events. Both reactions showed a predominantly T lymphocyte infiltrate with no polymorphonuclear leukocyte involvement. Apposition of Langerbans cells to lymphocytes in the epidermis was seen in both types of response. Considerable variability in the intensity of reaction to irritant and allergen occurred within individuals. There was no statistically significant difference between the intensity of the reactions to the irritant and the allergen.

Patch testing with 7 irritants has been performed on a panel of 42 healthy volunteers, with the aim of determining concentrations which would induce mild to moderate reactions in at least 75% of individuals tested. The irritants studied and their optimum concentrations were as follows: benzalkonium chloride, 0.5%; sodium lauryl sulphate, 5%; croton oil, 0.8%; dithranol, 0.02%; nonanoic acid, 80%; propylene glycol, 100%; sodium hydroxide, 2%. Responder rates lower than 75% had to be accepted for benzalkonium chloride and sodium hydroxide in order to prevent overly severe reactions, whilst propylene glycol proved to have only marginal irritant properties.

The histopathology of the primary irritant reactions induced after 48 h in human volunteers by benzalkonium chloride, sodium lauryl sulphate, croton oil, nonanoic acid, dithranol, and propylene glycol has been investigated. Patterns of epidermal damage were identified for each irritant, reflecting their differing chemical interactions with the cellular components of the skin.

Irritant contact dermatitis may be induced by many chemicals and has a far greater incidence than allergic contact dermatitis. Despite this, it receives relatively little attention and its pathogenesis remains poorly understood. To gain a greater understanding of the interaction of irritants with the skin, we investigated the histopathological changes resulting from the topical application of a series of structurally unrelated irritants. Human volunteers were patch-tested with appropriate concentrations of nonanoic acid, sodium lauryl sulphate, dithranol, benzalkonium chloride, croton oil, and propylene glycol, which produced generally mild to moderate responses. Biopsy specimens were taken after 48 h and examined by light and electron microscopy. Spongiosis and the infiltration of predominantly mononuclear cells were observed in the epidermis of the majority of biopsy specimens, and were particularly pronounced and extensive in croton oil reactions. In addition, several irritants induced distinct and characteristic patterns of keratinocyte damage. Nonanoic acid and sodium lauryl sulphate caused morphologic changes indicative of disturbances in keratinocyte metabolism and differentiation, giving rise to dyskeratosis and parakeratosis respectively, while dithranol induced marked swelling of keratinocytes in the upper epidermis. The results suggest that there is a diversity and specificity in the histopathology of irritant contact dermatitis, reflecting the different ways in which chemicals may interact with components of the skin.