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Biomedical subjects

O B Christensen

Publications and source records attributed to O B Christensen.

At least 37 records · Page 2Linked to original sources
PubMed1989

Clinical response and side-effects in the treatment of psoriasis with UV-B and -A novel dithranol formulation.

A new dithranol formulation (Dithranol-Biogram), in which the dithranol is microencapsulated by crystalline monoglycerides, has been developed. This stable formulation has pharmaceutical and cosmetic properties which overcome several draw-backs associated with conventional dithranol preparations. The clinical efficacy and side-effects of Dithranol-Biogram were compared to a conventional ex-tempore formulation in the treatment of 33 patients at a day-care centre. The study was designed as a randomized, single-blind, within-patient comparison. Patients were treated 4 times weekly for up to 6 weeks. Each session started with suberythematous UV-B doses followed by application of 1% dithranol for 20 min. There was no difference in clinical efficacy between treatments. Within 2-6 weeks the lesions in 21 of the 33 patients were classified as healed. The average reduction in severity score was 39%, 62% and 79% after 2, 4 and 6 weeks, respectively. The incidence of perilesional irritation was, however, several times higher for the ex-tempore treated sides. At the end of the study 21 patients preferred the Dithranol-Biogram formulation, 6 the ex-tempore formulation and 6 had no preference. The results of this study suggest that this novel formulation may become an important contribution to the management of psoriasis.

Adolescent↗
PubMed1987

Oral hyposensitization in nickel allergy.

In two controlled studies, each including 24 patients with contact allergy to nickel, different protocols were designed in an attempt to diminish the patients' hypersensitivity by oral administration of the antigen. With doses of 5.0 mg nickel sulfate taken once a week for 6 weeks, but not with 0.5 mg daily, the degree of contact allergy was significantly lowered, measured as patch test reactions before and after nickel administration.

Administration, Oral↗
PubMed1987

Fixed drug eruption: an immunohistochemical investigation of the acute and healing phase.

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.

Acute Disease↗
PubMed1987

UVB serum factor: suppression of allergic contact dermatitis in guinea pigs.

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.

Animals↗
PubMed1987

Open, closed and intradermal testing in nickel allergy.

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.

Adolescent↗
PubMed1987

Long term effect on epidermal dendritic cells of four different types of exogenous inflammation.

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.

Adult↗
PubMed1987

Local and systemic effect of UVB irradiation in patients with chronic hand eczema.

The effect of local as well as whole body irradiation with UVB was investigated in patients with chronic hand eczema not responding to conventional topical treatment. UVB irradiation of the hands was significantly more effective than placebo. Whole body UVB irradiation combined with additional irradiation of the hands proved to be even more effective than local treatment in clearing chronic hand eczema. Due to the relatively fast relapse of the hand eczema after the UVB treatment period maintenance treatment is warranted. This could possibly be carried out by the patients at home, but under surveillance by a dermatologist.

Adult↗
PubMed1986

Expression of OKT6 antigen by Langerhans cells in patch test reactions.

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.

Adult↗
PubMed1986

Does sodium cromoglycate have an effect on contact dermatitis?

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.

Administration, Cutaneous↗
PubMed1986

Natural history of dermatitis herpetiformis in southern Sweden.

A retrospective clinical survey of 96 patients with dermatitis herpetiformis (DH) was performed in two defined populations of 425,000 in southern Sweden. The incidence of DH was 1.05-1.13/100,000 inhabitants/year and the prevalence was approximately 20-25/100,000 inhabitants. In one-third of DH patients the age at onset was greater than 60 years. In women with DH a strong connection to thyroid dysfunction was observed, but also other conditions of probable autoimmune pathogenesis were found in both sexes. No connection to malignant disease was observed. DH seems to be less active the later in life it starts. Several patients with DH manage without dapsone or need dapsone just occasionally in connection with bouts. This is the case even without a gluten-free diet. Many mild cases of DH were observed without a gluten-free diet; therefore, this restricting regimen should be prescribed only in more active cases of DH.

Adolescent↗
PubMed1986

Local and systemic effect of ultraviolet irradiation (UVB and UVA) on human allergic contact dermatitis.

In subjects hypersensitive to nickel we have investigated local and systemic effect of whole body exposure of cumulative suberythema UVB doses as well as solarium-UVA exposure. UVB possesses both locally and systemically a suppressive effect on human allergic contact dermatitis, but UVA has no such effect. The systemic suppressive effect of UVB might be of therapeutic importance in patients with severe chronic dermatitis of the hands when adding this effect to a local suppressive effect. Also, patch testing should not be performed during UVB and/or overt sun exposure.

Adult↗
PubMed1985

Single exposure to ultraviolet irradiation and elicitation of human allergic contact dermatitis.

Ultraviolet radiation has been stated to inhibit afferent as well as efferent phases of allergic contract dermatitis. In this controlled study 17 female patients with nickel allergy were studied by three different protocols after an initial determination of their degree of hypersensitivity. They were patch tested with nickel sulfate immediately after UVB, 4-6 days after UVB, or immediately after external PUVA. Neither depressing nor enhancing of the allergic reaction was observed when compared to non-irradiated controls. The role of Langerhans cells as antigen-presenting cell playing an important role in the elicitation phase of allergic contract dermatitis is discussed and questioned.

Adolescent↗
PubMed1985

Pathogenesis of orally induced flare-up reactions at old patch sites in nickel allergy.

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.

Administration, Oral↗
PubMed1984

Effect of vehicle on elicitation of DNCB contact allergy in the guinea pig.

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.

Animals↗
PubMed1984

Flare-up reactions and desensitization from oral dosing in chromate-sensitive guinea pigs.

Flare-up reactions were induced in potassium dichromate hypersensitive guinea pigs by a single oral dose of 55 mg/kg. This dose is systemically toxic and higher than the dose required to induce the same reactions in humans. A total oral dose of potassium dichromate of 90-115 mg/kg induced immunological unresponsiveness for at least 6 weeks. With limitations, the guinea pig model may be helpful in screening the hyposensitization capacity of different haptens dosed orally.

Administration, Oral↗
PubMed1984

The Langerhans cells in healed patch tests reactions, before and after oral administration of nickel.

Langerhans cells (LC) were studied at the light and electron microscopic levels in normal skin and in positive patch test areas after long-term healing before and after the flare-up reaction induced by oral administration of nickel. A number of reactive changes indicating increased cell activity, similar to those found in positive patch tests 72 hours after allergen application, were registered in the test areas. Thus, strong reactive changes persist in the LC system after a fulminant contact allergic dermatitis, even beyond clinical healing. Some cellular reactions, especially pronounced after oral nickel provocation, indicate that much of the LC activity takes place on a superficial level of the epidermis. Oral nickel administration induced, among other things, an intense formation of lipid-like inclusions in the LC, formerly observed only in contact allergic reaction to nickel. Goniometric analysis of the LC cytomembrane showed that the concept "spotty damage" is probably erroneous and that the LC are not targets of destruction in contact allergy. Keratinocytes adjacent to LC exhibited membrane and cytoplasmic changes indicative of interaction between these two cell types. Combined fluorescence and electron microscopic analyses of contact allergic dermatitis using long series of sections have disclosed a variety of reactive changes in, and an increased activity of, the Langerhans cell system (1, 2). In the present study Langerhans cells (LC) have been scrutinized for reactive changes after long-term healing of challenged epidermis and after oral nickel provocation causing a flare-up reaction of healed patch test areas.

Administration, Oral↗
PubMed1982

Prognosis in nickel allergy and hand eczema.

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.

Cobalt↗