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Biomedical subjects

B Staberg

Publications and source records attributed to B Staberg.

At least 37 records · Page 2Linked to original sources

The effects of antipsoriatic treatment on cutaneous blood flow in psoriasis measured by 133Xe washout method and laser Doppler velocimetry.

In 8 patients with psoriasis vulgaris, the cutaneous blood flow (CBF) was measured simultaneously in both involved and uninvolved psoriatic skin before (i.e., on the first day of hospitalization) and on the 3rd, 7th, 14th, and 28th days of treatment with tar. The 133Xe washout method was used after epicutaneous labeling and compared to the laser Doppler velocimetry (LDV) technique. Control experiments were performed in 10 normal individuals. Before treatment the mean CBF in involved psoriatic skin was 62.6 +/- 18.7 SD ml X (100 g X min)-1, which is significantly higher than CBF of uninvolved skin in psoriatic patients, 9.5 +/- 4.0 SD ml X (100 g X min)-1, (p less than 0.01) and is 13.6 times higher than CBF in the normal individuals (p less than 0.01). Fifty hours following onset of treatment (i.e., after only 2 applications of tar), mean CBF of the involved psoriatic skin had decreased significantly to 35.0 +/- 13.9 SD ml X (100 g X min)-1, (p less than 0.01), which was not statistically different from the CBF on the 7th day. During the following weeks, the CBF in involved psoriatic skin decreased at a more moderate rate than that observed during the first week and was 15.0 +/- 6.1 SD ml X (100 g X min)-1 on the 28th day. This value is not significantly different from the CBF of uninvolved skin in these patients. At the end of treatment, the CBF of the uninvolved skin had decreased significantly (p less than 0.05) in all the patients to values similar to those observed in the skin of normal individuals. A parallel decline was observed in a clinical psoriatic score index; however, it is not known whether the observed decrease in CBF was preceded or succeeded by the clinical improvement. A comparison of the 133Xe measurements and LDV measurements in the normal individuals by linear regression analysis yielded a correlation coefficient of -0.24 (N = 20, p greater than 0.05). In the skin of psoriatic patients the correlation coefficient was 0.01, (N = 47, p greater than 0.05) for unaffected skin, and 0.61 (N = 47, p less than 0.001) in the involved psoriatic skin sites. The LDV measurements did not reflect changes in the uninvolved skin in psoriatic patients during treatment and resulted in a remarkably high C.V. in the bilateral measurements of skin in normal individuals (43.8%) compared to the C.V. of 133Xe flow measurements (14.8%). It is concluded that while the LDV method gives a rough estimate of blood flow in cutaneous tissue with a high capillary perfusion rate, inaccurate measurements are made in skin areas with normal to twice the normal CBF range.

Adolescent↗

Quantification of weal reactions with laser Doppler flowmetry. Comparative blood flow measurements of the oedematous centre and the perilesional flare of skin-prick histamine weals.

Skin-prick experiments with different concentrations of histamine (0.1 mg/ml, 1.0 mg/ml, 10.0 mg/ml) and isotonic NaCl solution for control were performed on the forearms of 10 healthy volunteers. Regular recordings of the cutaneous blood flow by laser Doppler flowmetry were performed in the centre of the weals and 5, 10, 15 and 20 mm from the centre representing the zone of perilesional flare. In the weal centre the blood flow was increased but neither different concentrations of histamine nor the control reaction could be differentiated. Recordings performed 5 and 10 mm from the centre showed, however, significant differences between the different solutions of histamine tested as well as the control reaction. The better differentiation was obtained 5 and 10 min after skin-prick. In conclusion, laser Doppler flowmetry with recordings of the perilesional flare is found useful for quantification of weal reactions.

Adult↗

Interaction between 8-methoxypsoralen and phenytoin. Consequence for PUVA therapy.

A patient with epilepsy and psoriasis in phenytoin therapy was treated with PUVA with no effect at all. The PUVA treatment failure was demonstrated as being due to abnormally low serum levels of 8-methoxypsoralen (8-MOP) during phenytoin therapy, while normal serum levels of 8-MOP were observed after phenytoin was discontinued. The effect is probably due to an induction of the hepatic enzyme system by phenytoin, leading to an increased metabolism of 8-MOP. Other drugs with hepatic enzyme inducing properties might possibly also interfere with psoralen metabolism with further consequences for PUVA therapy.

Drug Interactions↗

Quantitation of contact allergy in guinea pigs by measuring changes in skin blood flow and skin fold thickness.

Skin blood flow determined by laser Doppler flowmetry (LDF) and skin fold thickness (SFT) have been used to quantitate allergic contact dermatitis in the guinea pig maximization test (GPMT) using chlorocresol as the allergen. The closed patch test procedure itself influenced both LDF and SFT measurements when determined in 12 sham-treated guinea pigs. The LDF was maximal at 24 hours and the SFT at 48 hours. Before correlating the quantitative measurements with the conventional visual scoring in test and control animals the value from a nearby control site was subtracted from the test site values. The correlations were highly significant (p less than 0.001-0.05) indicating that the quantitative methods were useful supplements to the visual scoring as a measure of interobserver and interlaboratory differences.

Animals↗

Bioavailability study of two different 8-methoxypsoralen (8-MOP) preparations in patients receiving PUVA therapy.

A bioavailability study was performed with a pill containing microcrystalline 8-MOP and a soft gelatine capsule containing dissolved 8-MOP in 35 patients receiving PUVA treatment. Peak plasma levels were almost doubled after ingestion of the capsule preparation in comparison with those recorded from the pill takers. The pharmaceutical formulation of 8-MOP preparations is of decisive importance for the bioavailability of the drug. Variations in degree of absorption from different 8-MOP preparations and the existence of a metabolic first-pass effect probably explain the great inter-patient variability in therapeutic response. It is therefore advisable to individualize the dose of 8-MOP, primarily in slow responders, with the aim of obtaining a faster clearance but also to reduce the amount of UVA light involved.

Biological Availability↗

Dermal elastosis in hairless mice after UV-B and UV-A applied simultaneously, separately or sequentially.

The elastosis-inducing capacity of UV-A and UV-B was studied in the skin of hairless mice. After irradiation with UV-B and UV-A applied either simultaneously, separately or sequentially, the degree of elastosis in the dermis was microscopically evaluated. This semi-quantitative method showed no significant elastosis in the UV-A irradiated mice, and moderate elastosis in the UV-B irradiated mice. Heavy elastosis was observed when the mice were exposed sequentially to UV-B and a large dose of UV-A, but if a moderate dose of UV-A was given simultaneously with UV-B, the degree of elastosis was slightly reduced compared with the elastosis induced by UV-B alone.

Animals↗

The effect of phototherapy on extracellular water and transvascular protein exchange in psoriasis.

Seven patients with stable psoriasis vulgaris were treated with phototherapy (Goeckerman or PUVA) for 3 to 4 weeks. By combining the suction blister technique with studies on labelled albumin and inulin, the intra- and extravascular fluid volumes, the leakage of albumin from the total and the skin microvasculature, and the intra- and extravascular masses of albumin were measured before and after therapy. In accordance with previous studies, a shift of fluid from the intra- to the extravascular spaces, an increased leakiness of the involved skin microvasculature, and a lowered total mass of body albumin were found before therapy. Treatment induced a minor increase of the extracellular fluid volume [mean, 6.20 +/- 1.16 l/m2 (SD) v. 6.73 +/- 0.95 l/m2 (SD), P less than 0.1], a reduced vascular leakage of albumin from the involved skin vessels, and a significant increase of the total mass of albumin [mean, 124 +/- 20 g/m2 (SD) v. 139 +/- 30 g/m2 (SD), P less than 0.05]. The other measured variables did not change significantly. It is suggested that the observed change in extracellular fluid volume was mainly due to a treatment-induced decrease of the transepidermal water loss and/or a subclinical oedema of the skin, whereas the increase in total albumin mass was due to a reduction of the catabolism of the endogenous albumin caused by the decrease in the microvascular leakiness of the involved skin vessels.

Adult↗

Subcutaneous measurements of 133Xe disappearance with portable CdTe(Cl) detectors: elimination of interference from combined convection and diffusion.

Portable, solid state, cadmium telluride [CdTe(C1)] detectors were used for measurements of 133Xe-disappearance rate constants as a measure of subcutaneous (s.c.) blood flow. To eliminate the disturbance on the measurements from combined local convection and diffusion of xenon in the s.c. tissue, two methods were demonstrated to be feasible in both control persons and anaesthetized rabbits. A small volume (50-80 microliters) was injected into the s.c. tissue at a depth of 5 mm and the CdTe(C1) detector elevated 20 mm above the skin surface. In this situation identical disappearance rate constants were recorded by the CdTe(C1) detector and the NaI(T1) reference detector at 15-20 cm from the depot. Similiar results were obtained when either a large volume (greater than or equal to 800 microliters of Xe in humans) was injected into the s.c. tissue or the labelling was performed with a smaller volume in an atraumatic uniform manner to obtain a constant Xe concentration exceeding the field of view of the CdTe(C1) detector, which in these cases was attached directly to the skin surface. The coefficients of variation (CV) of the disappearance rate constants measured by the CdTe(C1) detector were 9% and 11%, and these values did not differ significantly from each other (P greater than 0.2), or from CV-values calculated from measurements with NaI(T1) detectors.

Adolescent↗

Quantification of cutaneous oedema in patch test reactions by measurement of skin thickness with high-frequency pulsed ultrasound.

69 doubtful and positive patch test readings (?+21, +23, ++18, 7) in 15 contact dermatitis patients were studied by measurement of skin thickness as an expression of allergic oedema. Exposed skin was compared with a regional control. Skin thickness was measured by 15 MHz pulsed ultrasound (A-scan) to 0.1 mm accuracy. The ?+, +, ++, and reactions could be separated by measurements of absolute difference in thickness (p less than 0.001, p less than 0.001, p less than 0.02) between exposed and non-exposed skin; the mean increases were 0.14, 0.49, 0.93, and 1.37 mm. The ?+, +, and ++ reactions, but not the reactions, could also be separated by measurements of relative increase in skin thickness (p less than 0.001, p less than 0.001, n.s.); the mean increases were 7%, 25%, 50% and 55%. The normal thickness of the skin of the back was shown to have increased (p less than 0.02) in patients with reactions only. It is concluded that the high-frequency ultrasound method is suitable for quantification of doubtful and positive patch test reactions. The reactions are probably explained by the normal thick skin of the back, and they need no separate recording in patch testing. Standards of increase in skin thickness in doubtful and positive patch tests are defined: absolute increase (mm) was ?+ less than or equal to 0.2; +0.3-0.7; ++0.8-1.3 ( greater than or equal to 1.4); relative increases were ?+ less than 15%; +15-45%, ++ ( included) greater than 45%.

Adult↗

Serum vitamin D metabolites in normal subjects after phototherapy.

The serum concentrations of the major vitamin D metabolites (25-hydroxyvitamin D(2 + 3) (25-OH-D), 1,25-dihydroxyvitamin D(2 + 3) (1,25-(OH)2-D), and 24,25-dihydroxyvitamin D(2 + 3) (24,25-(OH)2-D) were studied in 22 healthy male volunteers before and after one or two treatments with whole body UVB or PUVA in conventional doses. The effect of UVB was investigated in the autumn and early spring, whereas the effect of PUVA was investigated only in the autumn. The pre-treatment values of two metabolites were significantly reduced in the spring compared to the autumn level (25-OH-D: 14.0 ng/ml versus 22.0 ng/ml, P less than 0.02; and 24,25-(OH)2-D: 1.23 ng/ml versus 2.74 ng/ml, P less than 0.01), whereas the serum concentration of 1,25-(OH)2-D was not significantly reduced in the spring. After UVB, a small, but not significant, rise in all metabolites was observed in the spring, whereas virtually no changes were measured after UVB or PUVA in the autumn. We conclude that UVB and PUVA do not lead to harmful concentrations of vitamin D metabolites in the blood of healthy subjects.

24,25-Dihydroxyvitamin D 3↗

Suction blisters of the skin: a compartment with physiological, interstitium-like properties.

In six young men without known skin disease we evaluated whether mild suction to the skin significantly alters the properties of the underlying capillaries or whether suction blisters can be regarded as an interstitium-like compartment with dynamic physiological properties. Instead of the usual technique where the tracer is administered intravenously prior to the suction, we postponed the administration of the tracer (99mTc-DTPA) to 15 min after the suction blisters had been formed on the abdominal skin. We found that the final slope of average interstitium 99mTc-DTPA was almost parallel to that of the final slope of 99mTc-DTPA in the blister fluid (r = 0.917). During the period 120-240 min after the injection where the final slopes could be defined, the ratio between the amount of 99mTc-DTPA present in the interstitium and the amount of 99mTc-DTPA present in a blister fluid volume equal to interstitial fluid volume was 1.3. It is concluded that suction blisters of the skin behave like a dynamic interstitium-like compartment.

Adult↗

Activation of complement in the skin after PUVA therapy.

Suction blister fluid from the abdominal skin of 14 healthy subjects was examined for the presence of split products of complement C3 (C3-split) as an indicator of complement activation before and after treatment with either UVA or PUVA. Following PUVA a significant increase in C3-split was found (p less than 0.05) in both irradiated and non-irradiated skin areas. Following UVA the increase in C3-split was less pronounced. The activation of complement may play an important role in the maintenance of the delayed erythema that appears after irradiation with long-wave ultraviolet light.

Adult↗

Skin blood flow in psoriasis during Goeckerman or beech tar therapy.

Skin blood flow (SBF) was measured by the laser Doppler technique in lesional and clinically normal skin of 8 patients with psoriasis vulgaris during Goeckerman or beech tar therapy. The SBF measurements were performed before therapy and 1, 2, and 3-4 weeks after treatment was initiated. The results were compared to a clinical psoriasis index based on the objective assessment of infiltration, erythema, and scaling of the psoriatic plaques. The pre-treatment value of SBF in lesional skin was about 9 times higher than that of clinically normal skin. During therapy SBF of involved skin decreased rapidly approaching that of uninvolved skin after 3-4 weeks. Furthermore, there was a significant linear correlation between the SBF values and the clinical psoriasis index. It is concluded that SBF in psoriatic lesions decreases significantly during Goeckerman or beech tar therapy, and that this variable might be used to obtain a quantitative measure of the disease activity.

Adult↗

Patch test responses evaluated by cutaneous blood flow measurements.

We measured the cutaneous blood flow in positive standard patch test reactions by use of the laser-Doppler technique. The results were compared with conventional visual readings to develop a quantitative method. Compared with the basal blood flow in negative or nontested sites, the blood flow was significantly increased about fivefold in the doubtful reactions (?+), and about tenfold in both weak (1+) and strong (2+) positive reactions. The blood flows in the 1+ and 2+ reactions did not differ significantly from each other. No 3+ positive reactions were measured. We conclude that this method might be used to separate negative, doubtful, and positive reactions, whereas weak and strong positive reactions have to be differentiated by other means.

Adult↗