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Biomedical subjects

H Stege

Publications and source records attributed to H Stege.

48 records · Page 3Linked to original sources
PubMed1997

Evidence that singlet oxygen-induced human T helper cell apoptosis is the basic mechanism of ultraviolet-A radiation phototherapy.

Ultraviolet A (UVA) irradiation is effectively used to treat patients with atopic dermatitis and other T cell mediated, inflammatory skin diseases. In the present study, successful phototherapy of atopic dermatitis was found to result from UVA radiation-induced apoptosis in skin-infiltrating T helper cells, leading to T cell depletion from eczematous skin. In vitro, UVA radiation-induced human T helper cell apoptosis was mediated through the FAS/FAS-ligand system, which was activated in irradiated T cells as a consequence of singlet oxygen generation. These studies demonstrate that singlet oxygen is a potent trigger for the induction of human T cell apoptosis. They also identify singlet oxygen generation as a fundamental mechanism of action operative in phototherapy.

Antibodies, Blocking↗
PubMed1997

[Cream PUVA photochemotherapy].

Bath-PUVA-photochemotherapy lacks systemic side effects and requires low cumulative UVA doses, but a major disadvantage is the logistical requirement for bath tubs in a practice. We have developed an alternative form of topical PUVA therapy using a lipophilic emulsion vehicle for the photosensitizer 8-MOP (cream-PUVA-photochemo-therapy). A 0.0006% 8-MOP containing water-in-oil emulsion (30% H2O) was optimal for inducing photosensitivity in treated skin areas without increasing 8-MOP plasma levels. Increased skin photosensitivity was maximal 1 hour after cream application and persisted for 3 hours. We next assessed the effectiveness of cream-PUVA-photochemotherapy in the treatment of patients with chronic recalcitrant palmoplantar eczema (n = 10). In seven patients complete, and in two patients partial, remissions were observed after 40 treatments. Thus, cream-PUVA-photochemotherapy, which is easier to perform than bath-PUVA-photochemotherapy, is an effective, safe and low-cost modality, which may prove to become the topical PUVA therapy of choice for dermatological practitioners.

Dose-Response Relationship, Drug↗
PubMed1997

High-dose UVA1 radiation therapy for localized scleroderma.

BACKGROUND: Fibrotic skin lesions in patients with localized scleroderma can cause muscle atrophy, disfigurement, and flexion contractures. There is no effective therapy for this disease. Skin fibrosis is thought to be caused by decreased collagenase activity. Collagenase activity can be induced in dermal fibroblasts by UVA1 irradiation. OBJECTIVE: Our purpose was to assess whether UVA1 radiation therapy is effective for patients with localized scleroderma. METHODS: Patients with localized scleroderma (n = 17) were exposed 30 times to 130 J/cm2 UVA1 (high-dose UVA1 therapy; n = 10) or 20 J/cm2 UVA1 (low-dose UVA1 therapy; n = 7). Therapeutic effectiveness was assessed by evaluation of (1) clinical features, (2) thickness of sclerotic plaques, and (3) cutaneous elastometry. Sequential biopsy specimens from treated lesions were analyzed for collagenase I messenger RNA (mRNA) expression by semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS: In all patients, high-dose UVA1 therapy softened sclerotic plaques, and complete clearance was observed in four of 10 patients. High-dose UVA1 therapy significantly reduced thickness and increased elasticity of plaques. These changes could not be detected in unirradiated control plaques and were still present in 9 of 10 patients 3 months after cessation of therapy. For all factors assessed, high-dose UVA1 was superior to low-dose UVA1 therapy (p = 0.001). High-dose UVA1 therapy increased collagenase I mRNA expression about 20-fold in treated plaques. CONCLUSION: High-dose UVA1 therapy is effective in the treatment of localized scleroderma. Effectiveness is UVA1 dose dependent and is associated with induction of collagenase I expression.

Adult↗
PubMed1997

Chronically ultraviolet-exposed human skin shows a higher mutation frequency of mitochondrial DNA as compared to unexposed skin and the hematopoietic system.

Normal ageing processes are associated with an accumulation of mutations within the mitochondrial (mt) DNA. The most frequent mutation is a 4977 base pair (bp) deletion known as common deletion. In order to test the hypothesis that chronically sun-exposed skin is characterized by an increased mutation frequency of mtDNA, the mutation frequency of the common deletion between skin and another replicating tissue (the hematopoietic system) and chronically sun-exposed versus sun-protected skin was compared in the same individuals. This was done by comparing the amount of mutated mtDNA molecules with the whole mitochondrial genome in the same specimen with a semiquantitative polymerase chain reaction method, thus allowing direct comparison of different tissues. In all skin specimens the common deletion could be observed. In contrast only 3 of 10 blood samples revealed detectable amounts of the common deletion. Comparison of sun-exposed versus sun-protected skin exhibited a higher content of the common deletion in sun-exposed skin in 7 of 10 individuals. Additionally, a hitherto undescribed mtDNA mutation was detected exclusively in human skin. These studies indicate that exposure of human skin to solar radiation leads to an accumulation of mtDNA mutations, possibly via oxidative damage, which may play an important role in photoageing.

Adult↗
PubMed1995

Use of duplex sonography to investigate the effect of active and passive movement at the ankle joint for promoting venous return.

Among the joint and muscle pumps that are hemodynamically active and, in particular, bring about venous return in the lower limb, the so-called ankle pump is of paramount importance. The basic anatomical relationship of the talocrural joint to the venous network around the ankle is reviewed. Duplex sonographic measurement of the rate of blood flow in the great saphenous vein at the saphenous opening, at rest and during active and passive movements at the ankle joint, shows that such movements have an important effect on the rate of flow through the adjacent veins. Passive movement of the foot relative to the leg was brought about by a newly developed apparatus that can be either pneumatically or electrically operated. The action of the ankle pump against venous stasis, the arthrogenic congestive syndrome, and chronic venous insufficiency has demonstrated the prophylactic importance of this physiological mechanism. It can, when necessary, be replaced by an appropriately designed apparatus.

Adult↗
PubMedDate not supplied

Green light is effective and less painful than red light in photodynamic therapy of facial solar keratoses.

Photodynamic therapy (PDT) with topically applied delta-aminolevulinic acid (ALA) is increasingly employed to treat patients with multiple solar keratoses and superficial skin tumors. For these indications, ALA-PDT has been shown to be highly efficient. Treatment of multiple or extended lesions, however, is substantially hampered by the fact that ALA-PDT is associated with burning pain during the irradiation procedure. The standard irradiation devices commonly used for ALA-PDT emit red light around 630 nm. In the present half-side comparison study we have observed that ALA-PDT employing a green light irradiation device (543-548 nm) is equally effective, as compared with standard red light ALA-PDT. In contrast to red light ALA-PDT, however, green light ALA-PDT caused only little tingling and burning but no pain. These observations indicate that green light ALA-PDT is superior to standard ALA-PDT, because it is associated with less unwanted side effects.

Aged↗
PubMedDate not supplied

A new Salmonella surveillance and control programme in Danish pig herds and slaughterhouses.

The Danish Salmonella Surveillance and Control Programme for pigs operates at all stages of the production chain and has been applied nationally since 1995. Due to the program the level of Salmonella in Danish pork has declined from 3.5% in 1993 to 0.7% in the year 2000. Simultaneously, the number of human cases with salmonellosis due to pork has declined from approximately 1,144 in 1993 to 166 in 2000. In year 2001, the programme has been improved at a number of stages. A new classification scheme for the serological surveillance of finisher herds has been developed. The individual test cut-off in the mix-ELISA has been reduced to 20 OD%. Only herds producing more than 200 finishers/year are sampled. Based on the serological result from the last 3 months a new weighted salmonella index is calculated: The Danish Bacon and Meat Council has agreed on a new stricter penalty system. Level 2 and 3 herds get a penalty of 2% and 4% of the value per slaughter carcass, respectively. A new method of Salmonella testing on carcasses has been introduced; 5 carcasses per slaughter day are swabbed at 3 defined areas at 100 cm2 for each sample. This method is more sensitive than the one used previously. Herds infected with multiresistant Salmonella Typhimurium DT104 have to follow special restrictions. These include a requirement for a herd intervention plan, restriction on livestock trade, and a requirement for special slurry handling. Carcasses from DT 104 herds must be heat-treated or decontaminated with hot water.

Abattoirs↗