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J D Bos

Publications and source records attributed to J D Bos.

At least 37 records · Page 2Linked to original sources
PubMed2003

Evaluation of medium-dose UVA1 phototherapy in localized scleroderma with the cutometer and fast Fourier transform method.

PURPOSE: To evaluate the efficacy of medium-dose UVA1 phototherapy in patients with localized scleroderma. METHOD: A controlled pilot study with medium-dose UVA1 (48 J/cm2) was performed. The results were evaluated by means of a skin score and two objective methods for quantifying sclerosis (cutometer and fast Fourier transform method). Patients were treated 4 times a week for 5 weeks. The follow-up period was 12 weeks. RESULTS: All patients responded to therapy. Skin score and cutometer results showed improvement of skin elasticity of treated skin compared to control skin. Fast Fourier transform measurements showed no change in bundle orientation ratio and spacing. CONCLUSION: We concluded that treatment for 12 weeks 4 times a week with medium-dose UVA1 may be a beneficial therapy and a well-tolerated treatment modality for localized scleroderma (morphea). After 12 weeks, improvement of skin sclerosis can be detected by skin score and cutometer measurements but not by the fast Fourier transform method.

Adolescent↗
PubMed2003

Potential effect of patient-assisted teledermatology on outpatient referral rates.

We carried out a pilot study on the feasibility and accuracy of store-and-forward teledermatology based on patient-provided images and history as a triage tool for outpatient consultation. Patients referred by their general practitioner provided a history and images via the Internet. The information was reviewed by one of 12 teledermatologists and the patient then visited a different dermatologist in person within two days. Three independent dermatologists compared the remote and in-person diagnoses in random order to determine diagnostic agreement. Broader agreement was also measured, by comparing the main disease groups into which the two diagnoses fell. The teledermatologists indicated whether an in-person consultation or further investigations were necessary. There were 105 eligible patients, aged four months to 72 years, who were willing to participate. For the 96 cases included in the analysis, complete diagnostic agreement was found in 41% (n=39), partial diagnostic agreement in 10% (n=10) and no agreement in 49% (n=47). There was disease group agreement in 66% of cases (n=63). Nearly a quarter (23%) of participating patients could have safely been managed without an in-person visit to a dermatologist.

Adolescent↗
PubMed2002

Cyclosporin trough levels: is monitoring necessary during short-term treatment in psoriasis? A systematic review and clinical data on trough levels.

BACKGROUND: Cyclosporin is an effective treatment for severe plaque psoriasis. Unfortunately, its use may be limited by time- and dose-related nephrotoxicity. Serum trough levels may be useful for monitoring the risk of nephrotoxicity. OBJECTIVES: To determine whether monitoring of trough levels is necessary in psoriasis patients undergoing short-term treatment with cyclosporin. METHODS: A computerized and manual literature search identified studies on adults with plaque-type psoriasis treated with cyclosporin < or = 5 mg kg-1 daily, in which trough levels were measured in whole blood. Number of patients, treatment duration, formulation and dosage, renal function tests and trough levels were extracted. The association between renal function and trough levels was investigated. Additionally, in a randomized controlled trial on cyclosporin vs. methotrexate in moderate to severe psoriasis, cyclosporin trough levels were measured frequently in 20 patients during 12 weeks of treatment. The Pearson correlation coefficient between serum creatinine and cyclosporin trough levels was calculated. RESULTS: Fifty-six articles were found concerning cyclosporin trough level measurements in psoriasis patients, of which eight were analysed. Many studies were excluded due to inappropriate cyclosporin dosages used. As data were heterogeneous and lacked various key parameters, a correlation study and a meta-analysis could not be performed. Instead, a quantitative description of the literature was given. No high mean trough levels or elevations of serum creatinine were described. In our clinical study, all the mean trough levels in 17 patients treated with cyclosporin 3 mg kg-1 daily were within the therapeutic range (< 200 ng mL-1). Elevated trough levels were found in two of three patients treated with cyclosporin 3-5 mg kg-1 daily. No signs of renal dysfunction were seen. CONCLUSIONS: The literature does not provide a definitive answer on whether monitoring cyclosporin trough levels in patients with psoriasis should be standard practice. Our own data show no need for cyclosporin trough level monitoring during short-term treatment with cyclosporin 3 mg kg-1 daily. However, when cyclosporin doses are > 3 mg kg-1 daily, monitoring may be indicated.

Adult↗
PubMed2002

Atopiform dermatitis.

It is proposed to introduce the term 'atopiform dermatitis' to describe patients who have dermatitis with many of the characteristics of true atopic dermatitis, but who are not atopic. Atopy should be defined as the genetically determined and environmentally influenced syndrome in which the primary immunological abnormality is the production of allergen-specific IgE. It is suggested that by making a distinction between atopiform dermatitis and true atopic dermatitis, subsequent genetic, immunological and therapeutic studies will be improved. Furthermore, atopiform dermatitis would be a more appropriate diagnosis for the atopic dermatitis-like skin diseases that may occur in syndromes such as phenylketonuria, Schwachman's syndrome, Wiskott-Aldrich syndrome, Netherton's syndrome, Job's syndrome, selective IgA deficiency, agammaglobulinaemia and ataxia telangiectasia. In contrast to patients with true atopy, patients with atopiform dermatitis can logically be advised that allergen avoidance is not required, as they have no allergen-specific IgE.

Dermatitis, Atopic↗
PubMed2002

Hyperproliferation of normally quiescent keratinocytes in non-lesional psoriatic skin due to high calcium concentration (an organotypic culture model).

Calcium plays an important role in the regulation of different functions of keratinocytes. In the present work we studied the effect of different extracellular calcium concentrations (0.01 mM-2.0 mM) on the proliferation and differentiation of human keratinocytes in normal human and non-lesional psoriatic skin. Using explant culture model, the proliferative and differentiated subsets of keratinocytes were detected by specific antibodies related to cell proliferation [beta-1 integrin (CD29), proliferating cell antigen (Ki67), proliferating cell nuclear antigen (PCNA)] and differentiation [differentiated cell cytokeratins (K1/K10) and differentiating cell antigen (lectin Ulex europaius agglutinin, UEA-1)]. After 4 days of culturing at high Ca2+ (2.0 mM) we observed marked hyperproliferation among the normally quiescent keratinocytes of non-lesional psoriatic skin. In normal uncultured and cultured skin and in uncultured and two-day-cultured non-lesional psoriatic skin both at normal (1.2 mM) and at high (2.0 mM) Ca2+ concentration only one layer of basal CD29+/Ki67+/K1/K10-/UEA-1- cell was observed. In sections from non-lesional psoriatic skin cultured for 4 days in the presence of high Ca2+ (2.0 mM) this cell population has expanded from at least three layers above the basement membrane. This expanded cell population of the 4-day high Ca2+ cultured non-lesional skin showed clear PCNA positive staining on frozen sections with the strongest positivity among the most basal localized cells. These data suggest that (i) extracellular Ca2+ concentration can influence the proliferation of basal ("stem") keratinocytes, (ii) the proliferative response to high Ca2+ concentration of psoriatic non-lesional basal keratinocytes differs from that of normal basal keratinocytes, (iv) changes in the extracellular Ca2+ milieu might play a role in the induction of the hyperproliferative psoriatic lesion.

Calcium↗
PubMed2001

Oxidative breakdown and conversion of urocanic acid isomers by hydroxyl radical generating systems.

cis-Urocanic acid (cis-UCA), formed from trans-urocanic acid (trans-UCA) by photoisomerization, has been shown to mimic suppressive effects of UV on the immune system. It is our hypothesis that UCA oxidation products in the skin play a role in the process of immunosuppression. Recently, both UCA isomers were found to be good hydroxyl radical scavengers and in this context we investigated the formation of products resulting from the interaction of hydroxyl radicals with UCA. Hydroxyl radicals were generated by (1) UV/H(2)O(2) (photooxidation), (2) ferrous ions/H(2)O(2) (Fenton oxidation) and (3) cupric ions/ascorbic acid. Oxidation products were identified by spectrometric methods and assessed by reversed-phase HPLC analysis. The photooxidation of UCA was induced by UV-B and UV-C, but not by UV-A radiation. Photooxidation and Fenton oxidation of trans-UCA, as well as of cis-UCA yielded comparable chromatographic patterns of UCA oxidation products. Several of the formed products were identified. The formation of three identified imidazoles was shown in UV-B exposed corneal layer samples, derived from human skin.

Buffers↗
PubMed2001

SDZ ASM 981: an emerging safe and effective treatment for atopic dermatitis.

BACKGROUND: SDZ ASM 981 is a selective inhibitor of the production of pro-inflammatory cytokines from T cells and mast cells in vitro. It is the first ascomycin macrolactam derivative under development for the treatment of inflammatory skin diseases. OBJECTIVES: This study was designed to determine the safety and efficacy of SDZ ASM 981 cream at concentrations of 0.05%, 0.2%, 0.6% and 1.0% in the treatment of patients with atopic dermatitis and to select the concentration to be used in phase III studies. METHODS: This was a double-blind, randomized, parallel-group, multicentre dose-finding study. A total of 260 patients were randomly assigned to treatment with SDZ ASM 981 cream at concentrations of 0.05%, 0.2%, 0.6%, or 1.0%, matching vehicle cream, or the internal control 0.1% betamethasone-17-valerate cream (BMV). Treatment was given twice daily for up to 3 weeks. RESULTS: A clear dose-response relationship for SDZ ASM 981 was evident, with 0.2%, 0.6% and 1.0% SDZ ASM 981 creams all being significantly more effective than vehicle (P = 0.041, 0.001 and 0.008, respectively) in terms of baseline to end-point changes in the Eczema Area Severity Index (EASI) and pruritus score. The 1.0% cream was the most effective SDZ ASM 981 concentration. BMV was more effective than the SDZ ASM 981 creams tested in this study. It appears that the efficacy plateau was not reached with the SDZ ASM 981 creams within 3 weeks treatment. SDZ ASM 981 was well tolerated. Burning or a feeling of warmth were the only adverse events reported more frequently in the 0.6% and 1.0% SDZ ASM 981 treatment groups than in the vehicle treatment group (42.9%, 48.9% and 34.9%, respectively). Few systemic adverse events were reported during the study (headache was the most frequent systemic event reported by 15 of 252 patients) and none was considered to be related to treatment. The local tolerability profile of the 1.0% cream was similar to that of the lower concentrations. CONCLUSIONS: 1.0% SDZ ASM 981 cream, which was shown to be safe, well tolerated and the most effective concentration in this study, was selected as the concentration to be further developed in phase III studies.

Adolescent↗
PubMed2001

Natural course of physical and chronic urticaria and angioedema in 220 patients.

BACKGROUND: Information about spontaneous remission of chronic urticaria is limited. OBJECTIVE: To investigate the natural course of urticaria, we followed up 220 adults in a prospective study. METHODS: Patients were followed up for 1 to 3 years to evaluate interventions, to detect latent causes, and to study the natural course of urticaria. The diagnosis was made by detailed history-taking as well as laboratory and provocation tests. RESULTS: Thirty-five percent of all patients were free of symptoms after 1 year. In 28.9% of patients, symptoms had decreased. Spontaneous remission occurred in 47.4% of the patients in whom no cause of their urticaria and/or angioedema could be identified and in only 16.4% of the patients with physical urticaria. A cause could be identified in 53.1% of the patients. Thirty-six percent of the patients had idiopathic urticaria. Chronic idiopathic urticaria combined with physical urticaria occurred in 10.9%. CONCLUSION: In general, the prognosis for spontaneous remission is reasonable, with the exception of the subgroup (33.2%) with physical urticaria.

Adolescent↗
PubMed2000

Treatment of generalized vitiligo in children with narrow-band (TL-01) UVB radiation therapy.

BACKGROUND: Only a few clinical trials have been performed on the treatment of generalized vitiligo in children. Recently, narrow-band UVB therapy has been reported to be an effective and safe therapeutic option in adult patients with vitiligo. OBJECTIVE: We studied the efficacy and safety of UVB (311 nm) therapy in children with generalized vitiligo and evaluated the effect of the therapy on the quality of life in these children. METHODS: In an open trial, 51 children (20 males, 31 females) with generalized vitiligo were treated twice weekly with narrow-band UVB radiation therapy for the maximum period of 1 year. The Children's Dermatology Life Quality Index (CDLQI) was used to evaluate the psychosocial impact of disease and treatment and was scored before and after therapy. RESULTS: The treatment resulted in more than 75% overall repigmentation in 53% of patients and in stabilization of the disease in 80%. Responsiveness to therapy was positively correlated with localization of the lesions and the patients' compliance. Adverse events were limited and transient. The better the repigmentation grade, the better the CDLQI scores had improved. CONCLUSION: Narrow-band UVB therapy is effective and safe in childhood vitiligo; it also may significantly improve the quality of life.

Child↗
PubMed2000

The 500 Dalton rule for the skin penetration of chemical compounds and drugs.

Human skin has unique properties of which functioning as a physicochemical barrier is one of the most apparent. The human integument is able to resist the penetration of many molecules. However, especially smaller molecules can surpass transcutaneously. They are able to go by the corneal layer, which is thought to form the main deterrent. We argue that the molecular weight (MW) of a compound must be under 500 Dalton to allow skin absorption. Larger molecules cannot pass the corneal layer. Arguments for this "500 Dalton rule" are; 1) virtually all common contact allergens are under 500 Dalton, larger molecules are not known as contact sensitizers. They cannot penetrate and thus cannot act as allergens in man; 2) the most commonly used pharmacological agents applied in topical dermatotherapy are all under 500 Dalton; 3) all known topical drugs used in transdermal drug-delivery systems are under 500 Dalton. In addition, clinical experience with topical agents such as cyclosporine, tacrolimus and ascomycins gives further arguments for the reality of the 500 Dalton rule. For pharmaceutical development purposes, it seems logical to restrict the development of new innovative compounds to a MW of under 500 Dalton, when topical dermatological therapy or percutaneous systemic therapy or vaccination is the objective.

Absorption↗
PubMed2000

Dermal organization in scleroderma: the fast Fourier transform and the laser scatter method objectify fibrosis in nonlesional as well as lesional skin.

Scleroderma, a chronic, progressive disorder, is characterized by dermal fibrosis with collagen bundles orientated parallel to the epidermis. Simple objective parameters to evaluate disease progression and therapies are needed. We describe two methods, the laser scatter method and the fast Fourier transform (FFT), to measure collagen bundle orientation and spacing. Lesional sclerodermic skin (LS), nonlesional sclerodermic skin (nonLS), and control skin (CS) sections were evaluated for orientation ratio using the laser scatter method. The FFT was used to calculate orientation ratio, variation, and spacing of collagen bundles. Parameters were correlated with local and mean skin score measurements, on a scale of 0 (normal) to 3 (severely sclerotic). With both the laser scatter method and the FFT, orientation ratios of LS (respectively, 2.16 +/- 0.33 and 1.83 +/- 0.62) were significantly higher than CS (respectively, 1.70 +/- 0.35 and 1.38 +/- 0.15). NonLS orientation ratios (respectively, 1.92 +/- 0.15 and 1.48 +/- 0.44) were between LS and CS ratios. Orientation variation and bundle spacing of LS (respectively, 57.3 +/- 19.4 and 15.7 +/- 5.6 microm) were significantly reduced compared to CS (respectively, 73.8 +/- 15.0 and 18.9 +/- 1.9 microm). NonLS orientation ratios (respectively, 57.2 +/- 29.0 and 15.6 +/- 6.1 microm) were similar to LS. Bundles in LS are more parallel, show less variation in orientation, and are more densely packed than in CS. There was a linear correlation between mean skin score and orientation ratio. Local skin score was not linearly correlated to orientation ratio. Our findings suggest that nonLS dermis without clinical sclerosis already shows fibrotic characteristics. Both techniques were easy to use and suitable for objectifying dermal fibrosis in scleroderma lesions. FFT is more accurate and reproducible than the laser scatter method and allows simultaneous pathological evaluation of the location of the analyzed tissue sections. Future studies will need to focus on the correlation between clinical disease severity and collagen bundle characteristics.

Adolescent↗
PubMed2000

Calcipotriol ointment and cream or their vehicles applied immediately before irradiation inhibit ultraviolet B-induced erythema.

Results of ultraviolet (UV) B phototherapy can be improved by the application of calcipotriol, but studies are needed to decide how the two treatments should be combined. We studied the effect of UVB after application of calcipotriol ointment (50 microg g-1) and calcipotriol cream (50 microg g-1) and determined the optimal time of application of calcipotriol when combined with UVB phototherapy (280-350 nm), in a single-blinded randomized vehicle-controlled study of 37 healthy adult volunteers. Calcipotriol ointment or cream was applied randomly on five areas on the back at different time intervals from UVB irradiation. One area was left untreated as the control. Application times were the evening before, the morning before, 2 h before, immediately before, and immediately after irradiation. UVB irradiation was administered by TL20W/12 fluorescent tube lamps at increasing doses (20, 25, 32, 40, 50 and 64 mJ cm-2) to six subunits of each test area. Clinical assessment was performed 24 h after UVB irradiation by a blinded investigator. Calcipotriol ointment and cream were applied in 19 and 18 subjects, respectively, and erythema was measured for each application time quantified. We found that erythemal reactions were significantly smaller when calcipotriol ointment or cream was applied immediately before irradiation compared with all other application times. To explain these findings, a vehicle control study was performed. No difference in erythema was seen between calcipotriol medication and the vehicle controls. Spectrophotometric analysis of the calcipotriol cream and ointment showed no UV absorbance in the UVB range. No signs of photosensitization were noted. In conclusion, the vehicles of the calcipotriol ointment and cream inhibit the induction of erythema by UVB irradiation if applied immediately before phototherapy. Consequently, calcipotriol ointment and cream should not be applied directly before UVB irradiation; however, they may be applied at any time up to 2 h prior to or immediately after UVB irradiation. Possible explanations for this sunscreen activity are discussed.

Adolescent↗
PubMed2000

Synthesis of complement components C3 and factor B in human keratinocytes is differentially regulated by cytokines.

The complement system plays an important part in host defense and inflammation. Locally synthesized complement may perform these functions at tissue and organ level. In skin the keratinocyte is the major cell type, it is known to produce two soluble complement components, C3 and factor B. In this study we investigated the regulation of synthesis of these components in foreskin keratinocytes by cytokines. Human keratinocytes were cultured in the presence of supernatant of activated peripheral blood mononuclear cells, interleukin-1alpha, interleukin-2, interleukin-6, transforming growth factor-beta1, tumor necrosis factor-alpha, or interferon-gamma. C3 and factor B proteins were measured in culture supernatant by enzyme-linked immunosorbent assay and C3 and factor B transcripts in harvested cells by reverse transcriptase-polymerase chain reaction. Cultured keratinocytes constitutively produced C3 and factor B. Supernatant of activated mononuclear cells upregulated C3 and factor B production by 27- and 15-fold, respectively. interleukin-1alpha, interferon-gamma, and tumor necrosis factor-alpha upregulated C3 synthesis by 7-, 8-, and 22-fold, and interleukin-1alpha, interleukin-6, and interferon-gamma upregulated factor B synthesis by 3-, 3-, and 34-fold, respectively. Tumor necrosis factor-alpha induced production of C3 and interferon-gamma induced production of factor B were inhibited by cycloheximide. Cytokine induced upregulation of C3 and factor B proteins was always associated with the upregulation of levels of C3 and factor B mRNA. This indicated that, as expected, cytokine-induced enhancement in C3 and factor B levels was due to an increase in synthesis rather than their possible release from intracellular stores. In conclusion, synthesis of C3 and factor B in keratinocytes is regulated by some cytokines, known to be produced by inflammatory cells and keratinocytes.

Cells, Cultured↗
PubMed2000

Exposure to UVB induces accumulation of LFA-1+ T cells and enhanced expression of the chemokine psoriasin in normal human skin.

Normal human skin shows preferential (epi)dermal infiltration of CD4+ T cells upon acute UV exposure. To study the mechanism behind this feature we locally exposed healthy volunteers to doses of UV commonly encountered by the population. Expression of integrins on T cells and expression of adhesion molecules on dermal endothelial cells were quantitatively assessed by immunohistochemistry in situ. We also investigated the effects of ultraviolet-B (UVB) exposure on psoriasin and IL-16, two specific chemoattractant factors for CD4+ T cells, at messenger RNA (mRNA) level by semiquantitative reverse transcriptase-polymerase chain reaction and at protein level by immunohistochemistry. We found, at day 2 after exposure to four minimal erythema doses of UVB, predominant accumulation of LFA-1+/CLA-/VLA-4- T cells in the dermis. Concomitantly the expression of ICAM-1, but not that of E-selectin and VCAM-1, was upregulated on dermal endothelial cells. The increase in the number of dermal T cells was not due to proliferation because only 2% of the UVB-induced dermal T cells expressed the marker of proliferation Ki-67. Whereas exposure to 35 J/cm2 of ultraviolet-A (UVA), like UVB, induced a loss of intraepidermal T cells at day 2 after exposure, UVA induced neither any influx of T cells into the dermis nor any adhesion molecule upregulation on endothelial cells. In response to UVB exposure, the expression of psoriasin mRNA, but not of IL-16 mRNA, was upregulated; the expression of psoriasin protein was also found to be upregulated. These results suggest that LFA-1/ICAM-1 pathway and psoriasin are both involved in the accumulation of CD4+ T cells into UVB-irradiated skin, possibly via a recruitment mechanism.

Base Sequence↗
PubMed1999

Differential modulation of human epidermal Langerhans cell maturation by ultraviolet B radiation.

UVB irradiation of the skin causes immunosuppression and Ag-specific tolerance in which Langerhans cells (LC) are involved. We tested the effect of UVB on LC that had migrated out of cultured epidermal sheets derived from the skin that was irradiated ex vivo (200, 400, 800, or 1600 J/m2). Two separate subpopulations of LC were distinguished: large-sized LC with high HLA-DR expression, and HLA-DR-low, small LC. UVB stimulated the maturation of the former LC subset as demonstrated by enhanced up-regulation of CD80, CD86, CD54, CD40, and CD83 and reduced CD1a expression in comparison with unirradiated controls. In contrast, the latter LC exhibited little or no up-regulation of these molecules except for high CD1a expression and high binding of annexin V, indicating that they were apoptotic, although their CD95 expression was relatively low. Stimulation of enriched LC with CD40 ligand-transfected cells and IFN-gamma revealed that the release of IL-1beta, IL-6, IL-8, and TNF-alpha was enhanced by UVB. In comparison with HLA-DR-low LC, HLA-DR-high LC were the principal IL-8 producers as demonstrated by intracellular cytokine staining, and they retained more accessory function. There was no detectable secretion of IL-12 p70, and IL-18 production was neither affected by any stimulus nor by UVB. These results suggest a dual action of UVB on LC when irradiated in situ: 1) immunosuppression by preventing maturation and inducing apoptotic cell death in part of LC, and 2) immunopotentiation by enhancing the up-regulation of costimulatory molecules and the production of proinflammatory cytokines in another part.

Apoptosis↗