Search

Spatio-temporal precipitation is modelled for urban application at 1 h temporal resolution on a 2 km grid using a Spatio-Temporal Neyman--Scott Rectangular Pulses weather generator (WG). Precipitation time series for fitting the model are obtained from a network of 60 tipping-bucket rain gauges irregularly placed in a 40 by 60 km model domain. The model simulates precipitation time series that are comparable to the observations with respect to extreme precipitation statistics. The WG is used for downscaling climate change signals from Regional Climate Models (RCMs) with spatial resolutions of 25 and 8 km respectively. Six diferent RCM simulations are used to perturb the WG with climate change signals resulting in six very different perturbation schemes. All perturbed WGs result in more extreme precipitation at the sub-daily to multi-daily level and these extremes exhibit a much more realistic spatial pattern than what is observed in RCM precipitation output. The WG seems to correlate increased extreme intensities with an increased spatial extent of the extremes meaning that the climate-change-perturbed extremes have a larger spatial extent than those of the present climate. Overall, the WG produces robust results and is seen as a reliable procedure for downscaling RCM precipitation output for use in urban hydrology. [ABSTRACT FROM AUTHOR]

A major challenge in the emerging research field of coupling of existing regional climate models (RCMs) and hydrology/land-surface models is the computational interaction between the models. Here we present results from a full two-way coupling of the HIRHAM RCM over a 4000 km x 2800 km domain at 11 km resolution and the combined MIKE SHE-SWET hydrology and land-surface models over the 2500 km² Skjern River catchment. A total of 26 one-year runs were performed to assess the influence of the data transfer interval (DTI) between the two models and the internal HIRHAM model variability of 10 variables. DTI frequencies between 12 and 120 min were assessed, where the computational overhead was found to increase substantially with increasing exchange frequency. In terms of hourly and daily performance statistics the coupled model simulations performed less accurately than the uncoupled simulations, whereas for longer-term cumulative precipitation the opposite was found, especially for more frequent DTI rates. Four of six output variables from HIRHAM, precipitation, relative humidity, wind speed and air temperature, showed statistically significant improvements in root-mean-square error (RMSE) by reducing the DTI. For these four variables, the HIRHAM RMSE variability corresponded to approximately half of the influence from the DTI frequency and the variability resulted in a large spread in simulated precipitation. Conversely, DTI was found to have only a limited impact on the energy fluxes and discharge simulated by MIKE SHE. [ABSTRACT FROM AUTHOR]

EURO-CORDEX is an international climate downscaling initiative that aims to provide high-resolution climate scenarios for Europe. Here an evaluation of the ERA-Interim- driven EURO-CORDEX regional climate model (RCM) ensemble is presented. The study documents the performance of the individual models in representing the basic spatiotemporal patterns of the European climate for the period 1989–2008. Model evaluation focuses on near-surface air temperature and precipitation, and uses the E-OBS data set as observational reference. The ensemble consists of 17 simulations carried out by seven different models at grid resolutions of 12 km (nine experiments) and 50 km (eight experiments). Several performance metrics computed from monthly and seasonal mean values are used to assess model performance over eight subdomains of the European continent. Results are compared to those for the ERA40-driven ENSEMBLES simulations. The analysis confirms the ability of RCMs to capture the basic features of the European climate, including its variability in space and time. But it also identifies nonnegligible deficiencies of the simulations for selected metrics, regions and seasons. Seasonally and regionally averaged temperature biases are mostly smaller than 1.5 _C, while precipitation biases are typically located in the ±40% range. Some bias characteristics, such as a predominant cold and wet bias in most seasons and over most parts of Europe and a warm and dry summer bias over southern and southeastern Europe reflect common model biases. For seasonal mean quantities averaged over large European subdomains, no clear benefit of an increased spatial resolution (12 vs. 50 km) can be identified. The bias ranges of the EURO-CORDEX ensemble mostly correspond to those of the ENSEMBLES simulations, but some improvements in model performance can be identified (e.g., a less pronounced southern European warm summer bias). The temperature bias spread across different configurations of one individual model can be of a similar magnitude as the spread across different models, demonstrating a strong influence of the specific choices in physical parameterizations and experimental setup on model performance. Based on a number of simply reproducible metrics, the present study quantifies the currently achievable accuracy of RCMs used for regional climate simulations over Europe and provides a quality standard for future model developments. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increase in the number of climate studies addressing changes in extreme precipitation. A common step in these studies involves the assessment of the climate model performance. This is often measured by comparing climate model output with observational data. In the majority of such studies the characteristics and uncertainties of the observational data are neglected. This study addresses the influence of using different observational data sets to assess the climate model performance. Four different data sets covering Denmark using different gauge systems and comprising both networks of point measurements and gridded data sets are considered. Additionally, the influence of using different performance indices and metrics is addressed. A set of indices ranging from mean to extreme precipitation properties is calculated for all the data sets. For each of the observational data sets, the regional climate models (RCMs) are ranked according to their performance using two different metrics. These are based on the error in representing the indices and the spatial pattern. In comparison to the mean, extreme precipitation indices are highly dependent on the spatial resolution of the observations. The spatial pattern also shows differences between the observational data sets. These differences have a clear impact on the ranking of the climate models, which is highly dependent on the observational data set, the index and the metric used. The results highlight the need to be aware of the properties of observational data chosen in order to avoid overconfident and misleading conclusions with respect to climate model performance. [ABSTRACT FROM AUTHOR]

In this study the potential increase of extreme precipitation in a future warmer European climate has been examined. Output from the regional climate model (RCM) HIRHAM4 covering Europe has been analysed for two periods, a control period 1961-1990 and a scenario 2071-2100, the latter following the IPCC scenario A2. The model has a resolution of about 12 km, which is unique compared with existing RCM studies that typically operate at 25-50 km scale, and make the results relevant to hydrological phenomena occurring at the spatial scale of the infrastructure designed to drain off rainfall in large urban areas. Extreme events with one- and 24-hour duration were extracted using the Partial Duration Series approach, a Generalized Pareto Distribution was fitted to the data and T-year events for return periods from 2 to 100 years were calculated for the control and scenario period in model cells across Europe. The analysis shows that there will be an increase of the intensity of extreme events generally in Europe; Scandinavia will experience the highest increase and southern Europe the lowest. A 20 year 1-hour precipitation event will for example become a 4 year event in Sweden and a 10 year event in Spain. Intensities for short durations and high return periods will increase the most, which implies that European urban drainage systems will be challenged in the future. [ABSTRACT FROM AUTHOR]

We investigated the effect of changing the horizontal resolution of a regional climate model (RCM) on the simulation of hydrological extremes. We employed the results of three experiments of the RCM HIRHAM using a grid size of approximately 12, 25 and 50 km. These simulations were used to drive the hydrological model LISFLOOD, developed for flood forecasting at European scale. The discharge simulations of LISFLOOD were compared with statistics of observed river runoff at 209 gauging stations across Europe. The largest discrepancies in peak flow occurred in climates with a seasonal snow cover, which may be explained by inaccuracies in the simulated precipitation that accumulate over winter. Although previous studies have found that high resolution climate simulations result in more realistic patterns of extreme precipitation, especially in mountainous regions, we did not find conclusive evidence that the 12-km HIRHAM run generally yields a better simulation of peak discharges. At some gauging stations the model performance is increasing with increasing horizontal resolution of the RCM, while at other stations it is decreasing. However, the differences between the three experiments become less important in larger river basins. Above about 30 000km[sup2] and 120 000km[sup2], respectively, the 25- and 50-km runs generally provided a good approximation of the simulations based on the 12-km climatology. Under the A2 scenario of climate change, the changes in extreme discharge levels were similar between the three experiments at continental scale. At the scale of individual river basins, however, there were occasionally important differences. If we assume the 12-km HIRHAM simulation to be more realistic, the use of lower-resolution climate simulations may lead to an underestimation of future flood hazard. This means that results obtained with lower-resolution RCM simulations should be interpreted with care, as the grid scale of the climate model adds to the uncertainty. [ABSTRACT FROM AUTHOR]

Background and Objective: Various factors such as hormones, drugs, and ultraviolet (UV) radiation may influence patch test reactions. The aim was to study the individual variation in nickel reactivity, also in relation to the menstrual cycle., Methods: Thirty women allergic to nickel were studied for 7 months with patch tests with a serial dilution of nickel sulfate in water on four different test occasions. The patients belonged to two different eczema groups, one with nickel allergy, atopy, and pompholyx (12 patients); and the other with nickel allergy, but without both atopy and hand eczema., Results: None of the patients showed the same patch test reactivity on all four occasions, and the highest individual difference noticed was 250 times for the four test occasions. Furthermore, two of the patients had completely negative test reactions on at least one test occasion., Conclusion: The variation in nickel reactivity as shown in this article is of great importance and should be kept in mind when a patient has a positive history of allergic contact dermatitis but negative patch test results to nickel.

Background: Chronic wounds have been shown to exhibit elevated levels of several classes of proteinases. Plasminogen activators (PAs) are proteinases which play a major role in the biological processes involved in wound healing and abnormalities in PAs may play a role in the pathology associated with chronic wounds. Here, we investigated the expression of tPA and uPA activities in chronic venous ulcer biopsies., Patients and Methods: In 22 patients with chronic venous leg ulcers, punch biopsies were taken from the ulcer base, ulcer margin and uninvolved skin from the thigh of the affected limb and PA activities were assessed using in situ histological zymography., Results: tPA is the main PA activity in uninvolved skin but was reduced in ulcer margin skin and venous leg ulcer tissue compared to normal skin. uPA activity appeared throughout the ulcer margin skin but was at low levels in normal skin. Ulcer base tissue appeared to exhibit a plasminogen-independent proteinase activity not seen in normal or ulcer margin skin., Conclusion: PA activities are altered in and around chronic venous leg ulcers and their distribution suggests that blood vessels in CVI may be damaged and that the tissue is in an inflamed state.

Several factors, such as amount of allergen, vehicle, anatomic site, immunologic status and previous eczema, may influence delayed hypersensitivity reactions. In an extended model, we have studied the significance of previous allergic contact dermatitis for elicitation of delayed hypersensitivity to nickel in 25 nickel-allergic females. On 3 occasions, 8, 4 and 1 months before the final challenge patch testing, an experimental allergic contact dermatitis from nickel was induced on the lower back. At the challenge patch testing, 4 identical dilution series of nickel were tested on 4 areas on the lower back 3 with previous but healed dermatitis and 1 control area. The tests were read in a blind way. A significantly higher test reactivity was found at the areas with a previous allergic contact dermatitis, the shorter the time interval between the previous provocation and the challenge, the stronger the reaction. These results may be of importance for the understanding of factors contributing to chronicity of allergic contact dermatitis.

In total, 256 patients with bacteriologically verified impetigo contagiosa were included in three double-blind, parallel group, randomized, multi-centre trials, where the efficacy of hydrogen peroxide cream (Microcid) was compared with that of fusidic acid cream/gel (Fucidin). The trials were performed at 47 centres in three countries, Sweden, Germany and UK, and the results are compiled in the present report. During the course of the 3-week treatment period, 92 patients out of 128 (72%) in the Microcid group were classified as healed, compared to 105 patients out of 128 (82%) in the Fucidin group. This difference was not statistically significant. The reduction in composite sign severity score (the sum of the score for erythema, vesiculation/bullae, weeping and crusting divided by four) in each separate study was 73%, 78% and 84% in the Microcid group and 85%, 85% and 84% in the Fucidin group. No statistically significant differences were found in the separate studies or when compiling the studies in a meta-analysis. When the patients had been classified as healed, beta-haemolytic streptococci were eliminated in all patients treated with Microcid cream. Since treatment started before the result of the bacteriology was known, another 135 patients with negative skin culture were enrolled in the trials, i.e. 391 patients were included in the safety analysis. Out of these, 23 patients reported the occurrence of adverse events, mainly classified as mild. In conclusion, Microcid cream has been documented as a topical alternative to fusidic acid in the treatment of impetigo.

The efficacy of UV-B irradiation, administered by a new unit, Handylux, in patients with chronic hand eczema was investigated. 15 patients were treated in the clinic and 11 patients at home. Treatments were performed 4-5 x weekly for approximately 10 weeks. According to the strict criteria used for clearing, none of the patients cleared during the study, but 18 of the 26 patients were defined as much improved by the investigator, while 17 of the patients considered themselves as > 80% improved. The compliance in both groups was very good and side-effects limited and dose-related. According to our experience, the effect of high dose UV-B in chronic hand eczema is almost comparable to PUVA, and offers an opportunity for patients to treat themselves at home.

Patients with nickel allergy and different types of eczema with and without atopy were given a single oral dose of nickel sulfate. Blood levels and urinary excretion were determined by atomic absorption spectrophotometry. Urinary excretion of nickel was found to be dependent on age, decreasing with increasing age. When difference in age between the eczema groups was taken into account, the level of nickel in urine was significantly (p < 0.005) higher in the two atopy groups compared to the controls. This may indicate a higher intestinal absorption of nickel in atopic skin disease.

Chronic leg ulcer is a disease of long duration, occurring predominantly in elderly people. Traditionally, little interest has been devoted to the study of the impact of this disease on life quality. In the present study the Nottingham Health Profile (NHP) was used to assess disease influence on six areas of daily life, namely: pain, physical mobility, sleep, energy, emotional reactions and social isolation. Standard questionnaires were distributed to patients with chronic leg ulcers of venous, arterial or mixed venous-arterial origin, treated at the Department of Dermatology. Complete data were obtained from 125 patients. The disease had a marked impact on the patient's subjectively perceived health. Males exhibited remarkably elevated scores, compared to the normative scores for men, especially in the areas of pain, emotional reactions, social isolation and physical restrictions. For women the impact of leg ulcer disease, although obvious, seems much less marked than for males. An exceptionally long median duration of leg ulcer disease was found among shop-assistants. It is possible that preventive measures should be undertaken in this group. The duration of leg ulcer disease did not seem to influence the quality of life. Patients with long disease duration in fact reported fewer problems than those with shorter duration, suggesting adaptive mechanisms. This study indicates that male leg ulcer patients should be more closely observed for symptoms of emotional stress, pain, social isolation and impaired physical mobility. More efforts should be made to alleviate pain. Above all this study underlines the importance of considering not only the ulcer but the whole patient.

Chronic leg ulcers represent a major health-care problem with considerable socioeconomic impact. Patients with seemingly therapy-resistant leg ulcers are common to all clinics. The purpose of the present study was to (1) examine a group of patients with nonhealing venous leg ulcers treated with a double-layer bandage and (2) evaluate whether the addition of an interactive hydrocolloid wound dressing could initiate healing in these patients. Twenty-two patients with ulcers caused by venous insufficiency were included. The patients had a mean ulcer duration of 27.6 years. Duration of the present ulcer was at least 1 year (mean >/= 4.1 years). Twenty of the 22 patients showed massive lipodermatosclerosis. Before inclusion, all patients had used double-layer bandage consisting of a zinc-impregnated bandage or stocking and a self-adhesive compression bandage for 1 year or longer without improvement. The new regimen was a triple-layer treatment with the hydrocolloid water applied over the ulcer and the traditional double-layer bandage unchanged. Three patients were dropped from the study. Nineteen patients were followed until healing or for 10 months. Nine of the 19 patients who completed the study healed. Ulcer area was reduced by 70% or greater in 7 patients and by 30% to 40% in two patients. One ulcer did not respond to the treatment and worsened slightly. The results of this study were encouraging and indicate that the triple-layer treatment with the hydrocolloid dressing applied to the ulcer should be evaluated in a randomized, controlled study in patients with less pessimistic prognoses.

By means of a questionnaire sent to all medical units in Malmö, including primary care, homes for the elderly, and industrial health clinics, 275 patients with leg and foot ulcers were identified. With a population of 232,908 in Malmö, this corresponds to a prevalence of 0.12%, which is lower than reported by others. Since the response rate was high (88% total, Primary Care: 100%), the prevalence of 0.12% is, however, believed to be real and might be explained by the urban area investigated, with easy access to care and proximity to one somatic hospital. 50% of the patients with leg and foot ulcers were treated in Primary Care, and 30% of the leg ulcer patients were treated at the Department of Dermatology. 88% of leg and foot ulcer patients were over 75 years of age. Median age was 79.5 years, with 80 for women and 76.5 for men. In Primary Care the median age was 82. There was a predominance of women in the study population with an overall sex ratio of 3:1. A higher proportion of patients living alone was found in Primary Care. The etiology of the ulcers was considered to be "unknown" or "other" or else no statement was given in 36% of the leg ulcer- and 22% of the foot ulcer patients. This might reflect an overall uncertainty about the underlying etiological cause. Medially and laterally located leg ulcers were reported equally often, but there was also a great proportion of wholly or partially circumferential ulcers. 76% of the foot ulcers were located on the toes.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed hypersensitivity retest reaction 3 and 6 weeks after induction of allergic and irritant inflammation, was studied in 13 females with known hypersensitivity to nickel. An increased retest reaction compared to controls was observed only in sites of earlier specific allergic inflammation. Also a general down-regulation of the degree of hypersensitivity was observed at retesting.

The objective of this study was to compare the clinical efficacy and acceptability of two dithranol creams (Micanol and Amitase) in patients with plaque type psoriasis treating themselves daily at home. Thirty-five patients started with Amitase (0.1%) and 37 with Micanol (0.1%) applied at night in this 6-week single-blind parallel groups comparison study. Patients who responded more slowly than a theoretically estimated "standard" rate of improvement had their concentration increased to 0.25% at the visit after 2 or 4 weeks. By the end of the study slightly more than half of the number of patients remained on 0.1%. There was no difference between the treatment groups. In comparison with the level at start the composite sign severity score for patients in the Amitase group was reduced by 24% after 1 week, 36% after 2 weeks, 49% after 4 weeks and 62% after 6 weeks. The reduction in the Micanol group was similar. Patients in the Micanol group showed after 1 week of treatment more irritative reactions than patients in the Amitase group. At all follow-up visits, staining of perilesional skin was more prevalent in the Micanol group. Staining of clothing was, however, far more prevalent and severe for patients given the Amitase cream. It may be concluded that Micanol is an important alternative for home treatment of psoriasis.

Questionnaires concerning nursing care of leg and foot ulcer patients in three major care-giving sectors of the national health service, namely the Department of Dermatology, general hospital wards/clinics, and primary care, have been analysed. The overall response rate was 88% (primary care: 100%). Forms regarding 193 patients with leg ulcers and 64 patients with foot ulcers were analysed. Substantial differences in nursing care were noted between the three sectors. In 55% of the leg ulcers and 45% of the foot ulcers fibrin slough was present in the ulcer. Black, necrotic tissue was present in 8% of the leg ulcers and 22% of the foot ulcers. Profuse ulcer-exudation was most commonly reported for leg ulcer patients treated at the Department of Dermatology, while the majority of foot ulcers had only a mild exudation. Frequency of dressing changes varied between 1.4 times/week for leg ulcers at the Department of Dermatology and 9.2 times/week (foot ulcers 11.6) at general hospital clinics. Local wound dressings were exclusively chosen by physicians at the Department of Dermatology, mainly by physicians at general hospital clinics, and equally often by physicians and nurses in primary care. Time since last evaluation of the ulcer by a physician varied. At the general hospital clinics, 89% of the patients with leg ulcers had been seen by a physician within the last 2-month period. At the Department of Dermatology, 89% and in primary care 61% of the patients were examined within this period. 11% of the patients in primary care had never consulted a physician for their ulcers.(ABSTRACT TRUNCATED AT 250 WORDS)

The clinical effect, side effects, cosmetic properties and the patients preference between Micanol and other dithranol formulations were investigated in three separate studies combining UV-B phototherapy and a short contact dithranol regimen. Good clinical results without difference between Micanol and other dithranol formulations were obtained. Side effects, cosmetic properties and preferences were mostly in favor of Micanol. Therefore, a high patient compliance can be obtained with the new dithranol formulation.

There is concern about the long-term carcinogenic effects of psoralen and ultraviolet A radiation (PUVA) therapy for treatment of skin disorders. A study of 4799 Swedish patients (2343 males, 2056 females; mean age at first treatment 45.3 years, range 6-93; mean follow-up 6.9 years males, 7.2 years females) who received PUVA between 1974 and 1985 showed a dose-dependent increase in the risk of squamous cell cancer of the skin. Male patients who had received more than 200 treatments had over 30 times the incidence of squamous cell cancer found in the general population. Significant increases (p less than 0.05) were also found in the incidences of respiratory cancer in males and females, pancreatic cancer in males, and kidney and colonic cancer in females. This study confirms previous reports of a dose-dependent increase in the incidence of squamous cell cancer in patients treated with PUVA.

In this review, the concepts of hyposensitization, tolerance and hardening are defined. Studies concerning hyposensitization by different routes of allergen administration are mentioned. The most important studies in humans, as well as in experimental animals, regarding oral hyposensitization are then gone into more thoroughly. The possible mechanisms of hyposensitization are discussed. It is concluded that oral hyposensitization in humans is indeed possible. Furthermore, the reaction is antigen-specific, diminishes quickly, and it is probably the dose administered at a certain moment rather than the total amount of allergens ingested that is crucial when receiving hyposensitization. However, further performed studies do not justify the routine use of oral hyposensitization.

Several reports indicate that the prevalence of nickel sensitivity among females in the general population is around 10 per cent and probably is increasing, especially in schoolchildren. It has been claimed that there is such a high correlation between a positive history of nickel hypersensitivity and patch-test results that testing is unnecessary if there is a history of hypersensitivity. This is not true. Nickel hypersensitivity itself is not a serious health problem for the individual. However, when hand eczema also is present, the situation is quite different. Concerns about medical metal implants in nickel-sensitive persons appear to have been exaggerated, and nickel intake in food probably is not a serious difficulty, although some persons may be unusually sensitive. In dealing with the clinical problems of nickel dermatitis, we must not overlook prophylaxis. It seems important to introduce safe methods of ear piercing (a primary source of nickel hypersensitivity) and to spread information about the health hazard potential of the seemingly harmless sensitivity to nickel.

Salpeter-induced calcium deposits in ten patients showed a close clinical and histopathological similarity to the lesions of pseudoxanthoma elasticum. By electron microscopy and selected area diffraction analyses of the calcium deposits we find the changes indistinguishable from the changes previously described in involved skin of patients suffering from PXE. Clinically our patients were compared with the fourteen patients with traumatic calcification previously described.

22 DNCB sensitized guinea pigs were challenged with varying amounts dissolved in alcohol, acetone and olive oil. DNCB applied in alcohol resulted in almost 100% positive reactions; the test scores correlated to dose. When similar amounts were applied in alcohol and acetone, the former produced a significantly higher degree of positivity. The importance of defining allergen concentration, volume or weight of test substance applied and test area size, when comparing test results in guinea pigs and humans, is emphasized.

The flare-up reaction of old patch test sites following oral intake of antigen have been shown to be site and antigen specific reactions. Using enzyme and immunohistochemistry, the morphology of 6- to 8-week-old patch test sites, before and after oral challenge with nickel, was investigated. Before oral challenge, small scattered perivascular cell infiltrates consisting of macrophages, mast cells, T-lymphocytes, and OKT6+ dendritic cells were found in old patch test sites. In early and strong flare-up reactions combined with systemic toxicoderma-like reactions, polymorphonuclear leukocytes and lysed granular fragments from these cells were prominent. In slower flare-up reactions with little systemic involvement, T-lymphocytes predominated. We conclude that cells, probably macrophages, which are able to secrete inflammatory mediators promoting chemotaxis for polymorphonuclear leukocytes and/or T-lymphocyte proliferation, may play an important role in initiation of the flare-up reaction.

In the present study we produced allergic, irritant, ultraviolet and liquid nitrogen inflammation in human volunteers. Biopsies were taken from each test site and adjacent normal skin as control 4-5 weeks later. The monoclonal antibodies OKT 6 and HLA-DR were used for light microscopic detection of Langerhans' cells (LC). At all 4 post-inflammatory test sites the number of epidermal LC (OKT 6 positive as well as HLA-DR positive) were significantly increased compared to normal skin. Also, the density of dermal dendritic cells was increased in post-inflammatory test sites. The increased number of epidermal LC seems to be a result of inflammation and not a specific event strongly related to certain cutaneous inflammatory disorders. The present investigation supports the theory that epidermal LC play a role in skin homeostasis.

Serum from guinea pigs exposed to a single high dose of UVB and from controls was injected into the spleen of normal animals 5 days prior to sensitization. When 1.0 ml was transferred 4.5 h after irradiation, immunosuppression was obtained. Transfer of 1.5 ml of serum 2.5 h after irradiation failed to induce immunosuppression. This experimental model in guinea pigs might be valuable in further studies investigating the effect of other modalities of ultraviolet exposure (e.g., PUVA or high-dose UVA) on the release of soluble serum factor(s) inducing immunosuppression in allergic contact dermatitis.

Nickel concentration in serum and whole blood as well as nickel excretion in urine was assayed at different time intervals before and after ingestion of nickel sulfate in eight healthy volunteers during a three days study. The peak level of nickel in blood was reached 2.5 hours after nickel ingestion and the maximal urinary excretion of nickel was during the first eight hours after ingestion. Great individual variations in nickel concentrations in blood and nickel excretion in urine were observed. Analysis of nickel in both urine and serum reflects ingestion of a soluble nickel salt, but urine seems to be most reliable to follow.

63 female patients with nickel allergy and hand eczema were reinvestigated 6 years after the primary investigation. 30% of the patients were healed. Patients with the pompholyx-type eczema had the worst prognosis. The start of hand eczema was not correlated to any particular occupation. There was a strong correlation between a history of metal sensitivity and a positive patch test reaction. High frequencies of personal and family atopy were found, and atopy made the prognosis worse. Determination of serum IgE was not found to be of any use in predicting the prognosis in patients with nickel allergy and hand eczema.

Two cases with recurrent annular lesions of similar clinical appearance and course are described. The histopathological investigations showed in both cases dense and diffuse infiltrates mainly of polymorphonuclear neutrophilic leucocytes in the mid dermis. No fever, leucocytosis or elevated ESR were observed. Systemic corticosteroid treatment controlled symptoms but recurrence after treatment was withdrawn occurred in both cases. It is discussed if we are dealing with a variant of Sweet's syndrome or a new entity.

Chinese cabbage plants were watered with different concentrations of NiCl2 solutions and the effect on growth and uptake of nickel in the plants were studied. No toxic effect on plant growth was observed. A higher content of nickel was found in the plants exposed to more concentrated nickel solutions. Nickel contamination and its clinical consequences are discussed.

Open, closed and intradermal testing with NiCl2 was performed in 15 subjects with patch-test-proven allergy to 5% NiSO4 in pet. Intradermal testing proved to be a reliable method in confirming nickel sensitivity within 24 h. Open testing with non-toxic concentrations of NiCl2 in alcohol resulted in 73% and 93% positive reactions at 24 h and 48 h readings, respectively. This test method can be used as a reliable screening method in nickel allergy. Open testing often resulted in positive reactions within a few hours. This makes it possible to investigate pathogenetic events of acquired allergic contact dermatitis at a much earlier stage than with the usual 48-h occlusion. 24-h occlusion with Finn Chambers is not sufficient if one is to avoid false negative reactions in nickel allergy. Occlusion with Finn Chambers seems to delay the reaction.

Previous studies in humans and guinea pigs indicate that Langerhans cells (LC) participate in elicitation of allergic contact dermatitis. The number and morphology of LC was determined in acute and healed allergic patch test sites, control (petrolatum) sites and normal skin in nickel-sensitive individuals using OKT6 monoclonal antibody and avidin-biotin/peroxidase labeling. Compared to normal skin, the staining intensity and number of epidermal LC was significantly increased in allergic (p less than 0.02) and petrolatum control (p less than 0.02) sites, and in 6- to 8-week old allergic patch test sites (p less than 0.006). The in situ changes in LC induced by petrolatum alone may be a result of the occlusive patch test, or may suggest that petrolatum is not as neutral as previously believed. The nickel-induced increase in LC may indicate changes in the LC present in the epithelium at the time of testing, or migration of additional LC into the epithelium, which can then remain in situ for weeks after the antigenic challenge. The specificity of the LC increase in allergic contact dermatitis is questioned on the basis of the increase noted with petrolatum.

Five patients were each challenged orally with a drug which had previously induced a fixed drug eruption. A positive reaction occurred in all the patients. Punch biopsies were taken 6-12 h, 24 h and 3 weeks after challenge. The specimens were tested with different mouse anti-human monoclonal antibodies to identify T lymphocytes and phenotypic subsets, natural killer cells, B lymphocytes, OKT-6 and HLA-DR-positive cells. T suppressor/cytotoxic cells seemed to play a major role in initiating the flare-up reaction and preserving the cutaneous memory function of the fixed drug eruption.

Sodium cromoglycate was applied to the forearm of 9 subjects with known delayed hypersensitivity, and to the back of 14 dinitrochlorobenzene-sensitized guinea pigs before challenge with the allergen and sodium lauryl sulphate. Sodium cromoglycate did not decrease the intensity of allergic of toxic-irritant reactions in either humans or guinea pigs.