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Biomedical subjects

M Bruze

Publications and source records attributed to M Bruze.

At least 145 records · Page 8Linked to original sources
PubMed1989

Cyclobuta-dithymidine induction by solar-simulating UV radiation in human skin: II. Individual responses.

The purpose of this study was to examine cyclobuta-dithymidine (T*T) photoproduct induction and persistence in human skin exposed in situ to simulated solar UV radiation. Small areas of untanned skin in nineteen individuals were exposed using a solar UV apparatus that simulates both the spectrum and intensity of the UV portion of summer midday sunlight at 39 degrees N latitude. The equivalent of approximately 60 min of sunlight exposure (72KJ/m2) was administered, and T*T photoproducts were quantitated by enzyme-linked immunosorbent assay (ELISA) of DNA extracted from skin punch biopsies. Net yields of T*T photoproducts were determined in 10 individuals, with the majority (7 of 10) between 0.02 and 0.12 T*T per kilobase (Kb). The three remaining individuals had higher levels of photoproducts but were not unusually sensitive to solar UV as determined by minimal erythema dose (MED). Percentage loss of T*T photoproducts 4 h after exposure was determined in nine individuals to be 80.2 +/- 14.0%.

Adult↗
PubMed1988

Occupational dermatoses in workers exposed to resins based on phenol and formaldehyde.

During December 1985 and February 1986, an investigation was carried out into skin diseases among workers in a plant producing decorative equipment built of paper sheets impregnated with resol resins based on phenol and formaldehyde (P-F-R). A questionnaire was sent to all 238 employees and it was answered by 218 (91.6%). Previous and current dermatoses were reported by 98 workers and 89 of these were examined and patch tested. The patch testing was conducted with a standard test series and products from the working environment and revealed contact allergy to P-F-R in 9 persons and to formaldehyde in 1. Besides these 10 individuals with occupational allergic contact dermatitis, occupational dermatoses were diagnosed in an additional 20 workers; irritant contact dermatitis in 19 and chemical burn in 1. In total, the figure for occupational dermatoses was 30 (12.6%).

Adolescent↗
PubMed1988

Patch testing with a mixture of 2 phenol-formaldehyde resins.

1310 patients were routinely patch tested with a paratertiary-butylphenol-formaldehyde resin (PTBP-F-R), a resol resin based on phenol and formaldehyde (P-F-R-2), and a mixture of these 2 resins. Approximately 2.5 times more patients with contact allergy to phenol-formaldehyde resins were diagnosed when routinely patch tested with P-F-R-2 in addition to PTBP-F-R. Although patch testing with a mixture of both resins was not as good as patch testing with the 2 resins separately, it was better than testing only with PTBP-F-R, since 1.6 times more patients with contact allergy to phenol-formaldehyde resins were still diagnosed. P-F-R-2 is therefore recommended for routine patch testing, preferably as a separate patch test but otherwise as a mixture with PTBP-F-R.

Dermatitis, Contact↗
PubMed1988

Patch testing with nickel sulphate under occlusion for five hours.

Routine patch testing is usually performed with the allergens under occlusion for 48 h, but a shorter occlusion time would of course be more convenient for the patient. In this study, nickel was chosen as the substance with which to investigate whether routine patch testing with allergen exposure for 5 h is possible. Patch testing, using dilutions of nickel sulphate under occlusion for 48 h and 5 h, was compared in 8 nickel-sensitive females. The results show that equivalent patch test reactions were achieved when using higher concentrations of the nickel solutions under occlusion for 5 h.

Female↗
PubMed1988

Cyclobuta-dithymidine induction by solar-simulating UV radiation in human skin. I. Protection by constitutive pigmentation.

The induction and persistence of cyclobuta-dithymidine (T less than greater than T) photoproducts in human skin samples was measured following exposure to artificial solar radiation. DNA extracted from human epidermis, irradiated with the equivalent of 15 to 120 min of midday sunlight, was analyzed by enzyme-linked immunosorbent assay (ELISA). Heavily pigmented skin required 2- to 4-fold higher doses than non-pigmented skin to produce similar amounts of T less than greater than T photoproducts. These results demonstrate the effectiveness of constitutive epidermal pigmentation in protecting epidermal cell DNA from solar UV-induced damage.

DNA Damage↗
PubMed1988

Contact and photocontact allergy to glyceryl para-aminobenzoate.

High-purity glyceryl para-aminobenzoate was produced from a commercial source of the chemical by using a chromatographic technique. Negative test reactions to this purified substance were obtained when it was patch/photopatch-tested on 2 patients with contact and photocontact allergy to a nonpurified batch of glyceryl para-aminobenzoate.

4-Aminobenzoic Acid↗
PubMed1987

Contact allergy to the active ingredients of Kathon CG.

The preservative Kathon CG is a commercial preparation, consisting of 2 active ingredients and other components. 28 patients with contact allergy to Kathon CG participated in a study in which patch testing was performed with serial dilutions, and with 5 chromatographically separated fractions. All reacted to fraction IV, and 2 patients also to fraction II. Mass spectrometry and nuclear magnetic resonance spectrometry identified fraction II and IV to be the active ingredients; 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one.

Dermatitis, Contact↗
PubMed1987

Contact allergy to the active ingredients of Kathon CG in the guinea pig.

Preservative Kathon CG (K-CG) is a commercial preparation, consisting of the two active ingredients (a.i.), 2-methyl-4-isothiazolin-3-one (243-K-CG) and 5-chloro-2-methyl-4-isothiazolin-3-one (5243-K-CG) and also of other components. Both a.i. are known contact sensitizers in humans. In this study guinea pig maximization tests were performed with the a.i. in order to assess and compare the degrees of the sensitizing capacities. The animals were also rechallenged with the sensitizer and 4 chemically related compounds, all being preservatives or known ingredients in preservatives, in order to study the cross-reaction patterns. 5243-K-CG was demonstrated to be a strong sensitizer and 243-K-CG a weak sensitizer. With 5243-K-CG as the sensitizer, 4.5-dichloro-2-methyl-4-isothiazolin-3-one was a possible cross-reacting compound. Possible cross-reactivity was indicated between the a.i. when 243-K-CG was the sensitizer.

Animals↗
PubMed1987

Leukocyte migration in vivo and in vitro in patients with psoriasis.

Leukocyte migration in vivo was studied with a skin chamber technique in 21 patients with active psoriasis vulgaris and 18 with cleared psoriasis vulgaris. Measuring over 24 h, no difference was found between healthy volunteers and most patients with active psoriasis, although a subgroup of patients with long-lasting relapses showed subnormal migration values. In patients with cleared psoriasis on the other hand the in vivo leukocyte migration values were increased. In addition, leukocyte migration in vitro under agarose was studied, but no difference was found between healthy controls and patients with psoriasis, active or cleared.

Adult↗
PubMed1986

Contact allergy to 4,4'-dihydroxy-(hydroxymethyl)-diphenyl methanes: sensitizers in a phenol-formaldehyde resin.

A particular phenol-formaldehyde resin of the resol type (P-F-R-2) was shown in a previous study to be a good tracer of patients with contact allergy to phenol-formaldehyde resins. Eleven patients with sensitivity to P-F-R-2 participated in the study in which chromatographically separated fractions of P-F-R-2 were patch tested. This procedure was repeated until a positive reaction to a single substance was noted. In this study 3 new sensitizers are reported. Investigations by mass spectrometry and nuclear magnetic resonance spectrometry identified the compounds to be 4,4'-dihydroxy-3-(hydroxymethyl)-diphenyl methane (4,4'-H-3-HPM), 4,4'-dihydroxy-3,3'-di-(hydroxymethyl)-diphenyl methane (4,4'-H-3,3'-HPM), and 4,4'-dihydroxy-3,5-di-(hydroxymethyl)-diphenyl methane (4,4'-H-3,5-HPM). Six of the 11 patients reacted to at least one of these compounds. All 6 patients reacted to 4,4'-H-3,3'-HPM and 5 reacted simultaneously to 4,4'-H-3-HPM. Four patients reacted to all 3 compounds tested. By patch testing with serial dilutions (ethanol 99.5%) of the three 4,4'-H-HPM, positive reactions were noted down to 0.5 X 10(-6)%, 1.0 X 10(-6)%, and 1.3 X 10(-3)% w/v for 4,4'-H-3-HPM, 4,4'-H-3,3'-HPM, and 4,4'-H-3,5-HPM, respectively.

Allergens↗
PubMed1986

Sensitizing capacity of 2-methylol phenol, 4-methylol phenol and 2,4,6-trimethylol phenol in the guinea pig.

The sensitizing capacities of 2-methylol phenol (2-MP), 4-methylol phenol (4-MP) and 2,4,6-trimethylol phenol (2,4,6-MP) were investigated with the guinea pig maximization test. These compounds are known sensitizers in phenol-formaldehyde resins. The study was performed in order to assess and compare the degree of the sensitizing capacities of these chemically related substances. The animals were also rechallenged with the sensitizer and 5 chemically related compounds in order to study the cross-reaction patterns. 2-MP was demonstrated to be a strong sensitizer, 4-MP a moderate sensitizer and 2,4,6-MP a weak sensitizer. With 2-MP as the sensitizer, o-cresol and 2,4-dimethyl phenol were possible cross-reacting substances. p-cresol and 2,4,-dimethylol phenol were possible cross-reacting compounds for 4-MP. The chemical investigation by high pressure liquid chromatography indicated that the compounds tested were pure and separable.

Animals↗
PubMed1986

Contact allergy to the preservative Kathon CG.

Of 976 patients routinely patch tested with Kathon CG (Rohm & Haas), 300 ppm, 43 (4.4%) gave a positive reaction. Of 170 patients routinely tested with Kathon CG 250 ppm, 10 (5.9%) gave a positive reaction. Out of 34 patients tested with serial dilutions of Kathon CG, 17 (50%) reacted to 100 ppm, 8 to 30 ppm and 2 to 10 ppm. The concentration of 1000 ppm of Kathon CG was irritant in some cases, but 300 ppm was not irritant. Of the 976 patients tested with Kathon CG 300 ppm, 8 (0.8%) showed a "flare-up" reaction, indicating patch test sensitization. Of the 170 tested with Kathon CG 250 ppm, 2 (1.2%) were sensitized. When the patch-test-sensitized patients were retested with serial dilutions, they showed the same pattern as the other patients. 13 sensitized patients were use tested and 7 (54%) gave responses. In the literature, Kathon CG 100 ppm is recommended as the routine patch test concentration. However, 50% of the sensitive persons may then be overlooked. In our clinics, Kathon CG has become the second most common contact sensitizer, but the sensitivity cannot be traced in all patients with clinically relevant allergy without an unacceptable risk of patch test sensitization.

Biopsy↗